Environmental chemistry. A review of the literature published up to mid-1980

E nviron me nt a I C he m ist ry Volume 2 A Specialist Periodical Report Environmental Chemistry Volume 2 A Review ...

Author: H.J.M. Bowen

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E nviron me nt a I C he m ist ry Volume 2

A Specialist Periodical Report

Environmental Chemistry Volume 2

A Review of the Literature published up t o m i d - I 980

Senior Reporter

.

H J. M. Bowen, Department of Chemistry, University of Reading

R eporters M. L. Berrow, Macaula y Institute for Soil Science, Aberdeen J. D. Burton, University of Southampton P. A. Cawse, AERE, Harwell D. S. P. Patterson, Central Veterinary Laboratory, Weybridge P. J. Statham, University of Southampton A. M. Ure, Macaulay Institute for Soil Science, Aberdeen

The Royal Society of Chemistry Burlington House, London, W I V OBN

British Library Cataloguingin Publication Data Environmental chemistry. - Vol. 2. - (Specialist periodical report/Royal Society of Chemistry) 1. Environmental chemistry - Periodicals I. Royal Society of Chemistry 574.5 QD31.2

ISBN 0-85 186-765-0 ISSN 0305-7712

Copyright 0 1982 The Royal Society of Chemistry

All Rights Reserved No part of this book may be reproduced or transmitted in anyform or by any means - graphic, electronic, including photocopying, recording, taping, or information storage and retrieval systems - without written permissionfrom The Royal Society of Chemistry

Printed in Great Britain by Spottiswoode Ballantyne Ltd. Colchester and London

Preface

When the first volume of this series was published in 1975, it was hoped to produce a sequel within two years. In the event a change of editorship, combined with a certain inertia, have greatly extended the publication gap beyond what was originally intended. During this period the subject has passed through successive phases of hysteria (with respect to Cd, Hg, Pb, PCBs, efc.) and grant-grabbing (a governmental response to the first phase), and has now achieved moderate respectability in the more forward-looking academic centres. It is still a young subject and there are immense areas of ignorance inviting future study. The first volume emphasized environmental organic chemistry and this second volume is deliberately slanted towards inorganic chemicals, covering the broad fields of the atmosphere and the hydrosphere, soils, and human diets. Reviewers of all these subjects agree that far too little information is available on the chemical forms of the elements in environmental reservoirs, thus laying down a challenge to analytical chemists. Patterson’s broad review of mycotoxins is included partly to redress the balance of inorganic topics and partly because his article was produced far ahead of the deadline for contributions. 0 si sic omnes! It is not proposed to segregate organic, inorganic, and physical contributions in future volumes of this series, though the editor would be glad to hear from anyone who thinks this is desirable. He would also welcome suggestions for reviews in subsequent volumes.

November 1981 H. J. M. BOWEN

Contents Chapter 1 Inorganic Particulate M a t t e r in t h e Atmosphere By P. A. Cawse

1

1 Introduction Terminology

1 2

2 Methods of Sampling and Analysis Collection Systems Filters Methods for Specific Aerosols Collection of Dry Deposition and Rainwater Total Suspended Particulates Measurement of Particle Size Determination of Atmospheric Turbidity Remote Sensing of the Atmosphere Microscopy of Dusts and Fibres Biological Sampling and Monitoring Techniques Methods of Analysis

3 3 4

3 General Physical and Chemical Composition of Particulates Background Aerosols Marine Aerosols The Stratospheric Background Urban Aerosols Inorganic Particulate-Organic Interations Particle-size Associations of Elements Photochemical and Gas-phase Reactions Atmospheric Monitoring and Surveillance Networks Trends in Atmospheric Particulate Concentrations 4 Characteristics of Emissions from Specific Sources

Resuspension of Soil Resuspension of Marine Aerosol Volcanic Emissions Forest Fires Plants Combustion of Fossil Fuels Other Industrial Processes Emission from Motor Vehicles Source Identification Studies and Methods vii

5

6 7 7

10 10 11 13 15 17 17 20 21

22 25 25 27 28

30 32 32 33 34 35 36 36 38

39 40

viii

Contents 5 Atmospheric Transport and Dispersion of Particulates Regional and Long-distance Transport Dispersion Modelling Cycling of Elements and Global Inventories

42 42 45 47

6 Removal of Particulates from the Atmosphere Dry Deposition to Land Precipitation Scavenging Total (Wet + Dry) Deposition The Air-Sea Interface

50 50 52 53 56

7 Effects of Airborne and Deposited Particulates Hazard to Man Air-quality Indices and Standards for Particulate Pollutants Effects on Visibility Effects on Global Albedo and Climate

57 57 61 63 64

8 Future Research Needs and Conclusions

68

Chapter 2 The Elemental Content of Human Diets and Excreta BY H. J. M. Bowen 1 2 3 4

Introduction Outline of Ingestion, Absorption, and Excretion Methodological Problems Inputs, Outputs, Deficient Concentrations, and Oral Toxicities of the Elements Group IA: Li, Na, K, Rb, Cs Group IB : Cu, Ag, Au Group IIA: Be, Mg, Ca, Sr, Ba, Ra Group IIB : Zn, Cd, Hg Group IIIA: B, Al, Sc, Y, Lanthanides, and Actinides Group IIIB: Ga, In, T1 Group IVA: Ti, Zr, Hf Group IVB: Si, Ge, Sn, Pb Group VB: P, As, Sb, Bi Group VIB: S, Se, Te, Po Group VIIB: F, C1, Br, I Transition Metals of Groups V-VII: V, Nb, Ta; Cr, Mo, W; Mn, Re Transition Metals of Group VIII: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt 5 Summary

70 70 70 72 82 82 83 83 84 86 87 87 87 88 89 90 91 92 93

Contents

ix

Chapter 3 The Elemental Constituents of Soils ByA. M. Ure andM. L. Berrow

94

1 Introduction

94

2 The Alkali Metals: Lithium, Sodium, Potassium, Rubidium, and Caesium Geochemistry Weathering and Mobility Soil Contents

96 96 97 97

3 The Alkaline Earth Elements: Beryllium, Magnesium, Calcium, Strontium, and Barium Beryllium Geochemistry Weathering and Mobility Soil Contents Magnesium Geochemistry Weathering and Mobility Soil Contents Calcium Geochemistry Weathering and Mobility Soil Contents Strontium Geochemistry Weathering and Mobility Soil Contents Barium Geochemistry Weathering and Mobility Soil Contents

101 101 101 101 101 102 102 102 102 103 103 104 104 105 105 105 105 106 106 107 107

4 Titanium, Zirconium, and Hafnium Titanium Geochemistry Weathering and Mobility Soil Contents Zirconium Geochemistry Weathering and Mobility Soil Contents Hafnium Geochemistry Soil Contents

108 108 108 108 109 109 109 110 111 111 111 111

Contents

X

5 Vanadium, Niobium, and Tantalum Vanadium Geochemistry Weathering and Mobility Soil Contents Niobium Geochemistry Soil Contents Tantalum Geochemistry Soil Contents

111 111 111 112 112 113 113 113 114 114 114

6 The Lanthanides or Rare Earth Elements, and Yttrium and Scandium The Lanthanides and Yttrium Geochemistry Weathering and Mobility Soil Contents Scandium Geochemistry Weathering and Mobility Soil Contents

114 114 114 115 116 118 118 118 118

7 Molybdenum and Tungsten Geochemistry Weathering and Mobility Soil Contents

119 119 120 120

8 Chromium, Manganese, Iron, Cobalt, and Nickel

123 123 123 123 123 125 125 126 126 129 129 129 130 131 131 131 132 133 133 134 134

Chromium Geochemistry Weathering and Mobility Soil Contents Manganese Geoc hemistry Weathering and Mobility Soil Contents Iron Geochemistry Weathering and Mobility Soil Contents Cobalt Geochemistry Weathering and Mobility Soil Contents Nickel Geochemistry Weathering and Mobility Soil Contents

Contents

xi

9 Copper, Zinc, and Cadmium Copper Geochemistry Weathering and Mobility Soil Contents Zinc Geochemistry Weathering and Mobility Soil Contents Cadmium Geochemistry Weathering and Mobility Soil Contents 10 The Noble Metals Silver Geochemistry Weathering and Mobility Soil Contents Gold and the Platinum Metals Geochemistry Weathering and Mobility Soil Contents 1 1 Mercury Geochemistry Weathering and Mobility Soil Contents 12 Boron, Aluminium, Gallium, Indium, and Thallium Boron Geochemistry Weathering and Mobility Soil Contents Aluminium Geochemistry Weathering and Mobility Soil Contents Gallium Geochemistry Weathering and Mobility Soil Contents Indium Geochemistry Weathering and Mobility Soil Contents Thallium Geochemistry Weathering and Mobility Soil Contents

136 136 136 136 138 139 139 139 140 143 143 143 143 146 146 146 146 147 147 147 148 149 150 150 151 15 I 155 155 155 156 156 157 157 158 158 159 159 160 160 161 161 161 161 162 162 162 162

Contents

xii 13 Carbon, Silicon, Germanium, Tin, and Lead Carbon Geochemistry Weathering and Mobility Soil Contents Silicon Geochemistry Weathering and Mobility Soil Contents Germanium Geochemistry Weathering and Mobility Soil Contents Tin Geochemistry Weathering and Mobility Soil Contents Lead Geochemistry Weathering and Mobility Soil Contents

162 162 162 163 163 164 164 164 165 166 166 166 166 167 167 167 167 168 168 168 169

14 Nitrogen, Phosphorus, and Sulphur Nitrogen Geochemistry Weathering and Mobility Soil Contents Phosphorus Geochemistry Weathering and Mobility Soil Contents Sulphur Geochemistry Weathering and Mobility Soil Contents

173 173 173 173 174 175 175 175 175 176 176 176 177

15 Hydrogen and Oxygen Hydrogen Geochemistry Weathering and Mobility Soil Contents Oxygen Geochemistry Weathering and Mobility Soil Contents

179 179 179 179 179 179 179 180 180

...

Contents

xi11

16 The Halogens: F, Cl, Br, and I

Fluorine Geochemistry Weathering and Mobility Soil Contents Chlorine Geochemistry Weathering and Mobility Soil Contents Bromine Geochemistry Weathering and Mobility Soil Contents Iodine Geochemistry Weathering and Mobility Soil Contents 17 Arsenic, Selenium, Antimony, and Bismuth Arsenic Geochemistry Weathering and Mobility Soil Contents Selenium Geochemistry Weathering and Mobility Soil Contents Antimony Geochemistry Soil Contents Bismuth Geochemistry Soil Contents 18 Thorium and Uranium Geochemistry Weathering and Mobility Soil Contents 19 Radionuclides 20 Organic Soils 21 Conclusions

Chapter 4 Mycotoxins By 0.S. P. Patterson

180 180 180 18 1 182 183 183 183 183 184 184 185 185 186 186 186 186 188 188 188 188 189 19 1 19 1 192 192 194 194 194 195 195 195 196 196 196 197 199 20 1

203 205

1 Introduction

205

2 Biogenesis of Mycotoxic:

206

Contents

xiv

3 The Importance of Mycotoxins in the Environment Mycotoxins in Food and Feeds Toxicological Potencies of Mycotoxins General Attributes of Mycotoxic Disease Clinical Diseases of Farm Animals Caused by Mycotoxins Human Mycotoxicosis

209 209 209 212 213 213

4 Analysis of Mycotoxins The Analytical Problem Sampling Procedures Analytical Methods 5 Occurrence in Food and Animal Feed Contamination Resulting from Direct Fungal Attack Indirect Contamination of Food

216 216 217 218 22 1 22 1 223 224 2 24 227 227 229 229 230 230 23 1 23 1 23 1 23 1 232 233 233

6 Metabolism and Mode of Action of Mycotoxins

Metabolic Activation and Detoxification Reactive Toxin Molecules Aflatoxin and Related Compounds Ochratoxin A T2-toxin and Related Trichothecenes Zear alenone Metabolism and Toxic Residues 7 Control of Mycotoxins in the Food Chain Genera1 Control of Fungal Infection Control by Selection Detoxification of Aflatoxin Promising Decontamination Processes Mycotoxins other than Aflatoxin

Chapter 5 Occurrence, Distribution, and Chemical Speciation of some Minor Dissolved Constituents in Ocean Waters By J. D. Burton and P. J. Statham 1 Introduction 2 Individual Elements C aesium Barium Aluminium Thallium Germanium Tin Lead Arsenic Antimony

234 234 235 235 235 237 238 238 238 238 240 242

xv

Contents

Bismuth Selenium Iodine Zinc Cadmium Mercury Vanadium Chromium Manganese Iron Cobalt Nickel Copper Molybdenum Silver Gold 3 Additional Aspects of Chemical Speciation

Author I ndex

242 242 244 246 249 250 25 2 252 25 3 257 259 25 9 260 263 26 3 263 263 26 7

1 Inorganic Particulate Matter in the Atmosphere ~~

BY P. A. CAWSE

1 Introduction Inorganic particulate matter that is raised to the atmosphere by both natural and artificial (anthropogenic) sources is mainly distributed in the lower troposphere. The upper boundary of the troposphere, the tropopause, is found at 11-17 km above the earth's surface depending on latitude. Volcanic eruptions may inject particles through the tropopause boundary to the stratosphere, which extends to the stratopause at -SO km altitude. Interplanetary debris from micrometeors may also provide a small contribution to particle loads in the atmosphere. Particulates in the stratosphere will be subject to a global distribution, whereas material injected to the troposphere will be transported in the zonal circulation before returning to the earth's surface. These transport pathways from sources to sinks determine the local, regional, and global nature of pollution, and eventually, possible effects on biological targets.' The inorganic fraction generally comprises 80-90% of the total suspended particulates (TSP) in the atmosphere; of the remainder, benzene-saluble organic compounds may amount to 5% and biological debris, including bacterial and fungal spores, are also present. In the Antarctic aerosol practically all of the mass is attributed to SO:-,* but in a non-urban area at Chilton (Oxon) for example, 50% of TSP was accounted for by SO:-, NOT, NH;, and NaCl with a further 3% from Ca, K, and Mg:3 Fe and A1 can typically account for 2-3% of the particulate m a s 3 Potentially toxic metals such as Pb can constitute 1% in urban environments, but 0.1% in remote areas.4 Concentrations of suspended particulates in urban environments throughout the world show annual mean values between 60 and 500 pg m-3.5 The changing quality of the atmosphere in England since medieval times6 and public concern towards increasing industrial pollution demonstrate the historical importance of anthropogenic inputs to the atmosphere and disturbance to the natural background of airborne particulates. Today we are faced with changes in I

T. M. Sugden, Philos. Trans. R . SOC.London, Ser. A , 1979,290,469. W. Maenhaut and W. H. Zoller, J. Geophys. Res., 1979,842421. P. A. Cawse, AERE Harwell Report R 7669, H.M.S.O., London, 1974. W. Bach, Rev. Geophys. Space Phys., 1976, 14,429. World Health Organisation, Environ. Health Criteria 8, W.H.O., Geneva, 1979. P. Brimblecombe, J. Air Pollut. Control Assoc.. 1976. 26, 94 1. P. Brimblecombe, J . Air Polluf.Control Assoc., 1978, 28, 115.

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systems of energy production and manufacturing processes that will affect both the output and nature of particulate emissions. Trends in atmospheric composition must therefore be recorded to assess the impact of these changes on the environment and to decide on the need for controls on emissions. The annual consumption of coal in England and Wales is now approaching 80 million tonnes, a record level, and activities of this magnitude demand very careful assessment of environmental consequences.* Total particulate concentrations in the atmosphere and levels of associated elements of potential toxicity such as As, Cd, Pb, and Se may present a nuisance or serious hazard to man and animals by inhalation and ingestion of contaminated food. Deposition of aerosols may induce a response in soil and water ecosystems, for example by acidification and accumulation of metals. Deterioration in visibility caused by suspended particulates and their role in modification of the world climate by disturbing the transfer of radiant energy are of major concern.’ The presence of increased concentrations of water soluble ions such as SO:- and NO: in polluted aerosols may influence natural processes of nucleation.’ Hence, pollution is now being recognized as a complex international as well as a national problem. This report is aimed at broad coverage of recent advances in research on inorganic particulates in the atmosphere, mainly from 1975 onwards. Studies on the fate and effects of such materials are included. Within this remit, some 1500 references have been identified of which a selection are quoted here to demonstrate the diversity of research developments. Advances in industrial engineering techniques to control emissions and improve workroom atmospheres are extensively reviewed elsewhere. ’O-I4 Over the past 25 years, a contrast is evident between earlier localized investigations of the atmosphere and present day research projects on a global scale not only in the troposphere but also extending to the ~tratosphere.’~ Classification of papers submitted to ‘Atmospheric Environment’ from 1973-1977 has shown more emphasis on aerosol (physico-chemical) research, comprising 46% of papers, than on gaseous species (34%); atmospheric transport and modelling account for 20% and cover both particulate and gaseous forms.I6 In fact the total number of articles has increased exponentially since 1960. l 6 Research on inorganic particulates in the atmosphere, their transfer pathways and effects has now become more inter-disciplinary, demanding the efforts of meteorologists, oceanographers, agriculturists, and medical and veterinary specialists, in addition to atmospheric chemists and physicists. Terminology.-An aerosol is a system of fine solid or liquid particles in gaseous suspension, collectively referred to as ‘particulates’. Dust refers to a relatively

lo

C . England, C.E.G.B. News Letter, 112, 1980. World Meteorological Organisation. Spec. Environ. Rep. 10, W.M.O., Geneva, 1977. H. E. Hesketh. ‘Understanding and Controlling Air Pollution’, 2nd Edn., Ann Arbor, Michigan, 1974.

H. E. Hesketh. ‘Fine Particles in Gaseous Media’, Ann Arbor, Michigan, 1977. R. Dennis (ed.), ‘Handbook on Aerosols’, NTIS, Springfield, VA, 1976. l 3 L. Theodore and A. J. Buonicore, ‘Jndustrial Air Pollution, Control Equipment for Particulates’, CRC Press, Cleveland. Ohio, 1976. l 4 A. C. Stern (ed.), ‘Air Pollution’, Academic Press. New York. 1977, Vol. IV. I ’ 1 - l . W. Georgii, Pugeoph. B a s k , 1978, 116, 215. l 6 R. R. Husar,Afmos. Environ., 1979, 13, I 1 1 . I’

Inorganic Particulate Matter in the Atmosphere

3

coarse range of solid particles (diameter, d > 1 pm), produced by disintegration of minerals or from resuspension by wind when sand-blasting of soil particles may often cause comminution. Fine particles formed from the gas phase by condensation are termed ‘smoke’ and ‘fume’. In the case of fume the particles are generally from 0.01-1 pm diameter, and are often observed as agglomerates of smaller particles. Suspended particulate matter < 15 ,um diameter is usually defined as smoke. Liquid droplets are often referred to as mists (d > 40 pm) and fogs (d = 5 - 4 0 pm). Small hygroscopic particles, or condensation nuclei, are classified into Aitken nuclei (d < 0.2 p),large (d = 0.2-2 pm), and giant (d > 2 p )types. The term ‘haze aerosol’ is frequently encountered in optical studies and includes any airborne particles that affect visibility. The fundamental properties and behaviour of aerosols and their formation from gases are the subject of several texts,11,17~18 Research on aerosol electrical properties have been discussed by several authors at a recent conference. l9

2 Methods of Sampling and Analysis

Collection Systems.-Several collection systems are available for sampling ‘total’ particulates in the atmosphere by filtration, for determination of mass or detailed chemical analysis;20 the EPA High Volume sampler and the German ‘LIB’ unit21 are examples. However, errors in sampling associated with various systems and devices used out-of-doors are well r e ~ o g n i z e d . ~Errors ~ - ~ ~may result from particle impaction or diffusion to the sampling probe or inlet manifold, and from the influence of increasing wind speed on the inertia of larger particles and thus on the particle size spectrum that is collected at a given intake velocity. The intake efficiency of 17 sampling devices under outdoor conditions showed great variation for particles between 20-50 pm diameter.25 Tests on a sampler with inlet velocity of 70 cm s-I established that at wind velocities >4 m s-l, particles over 10 pm diameter were collected with < 15% efficiency: 26 sampling of this restricted range of particle size may be considered adequate if the objective is to assess respirable particles. Other workers have recommended that high volume samplers are operated inside shelters to prevent particles being deposited on2’ or blown off 28 the filter during idle hours. B e n a ~ - i concluded e~~ from laboratory tests of the EPA High Volume sampler K . Friedlander, ‘Smoke, Dust and Haze’, J . Wiley, New York, 1977. A. C. Stern (ed.), ‘Air Pollution’, Academic Press, New York, 1976, Vol. 1. l9 H. Dolezalek, R. Reiter, and H. Landsberg, ‘Electrical Processes in Atmospheres’, D. Steinkopff, Darmstadt, 1977. A. C. Stern (ed.), ‘Air Pollution’, Academic Press, New York, 1976, Vol. 111. E. Herpetz, Staub. Reinhalt. L u f , 1969, 29, 408. 22 N. A. Fuchs, Atmos. Environ., 1975, 9,697. l 3 J. P. Lodge, ‘Accuracy in Trace Analysis’, ed. P. D. La Flew, N.B.S., Washington DC, 1976, p. 3 11. 24 M. Zier, Z . Meteorol., 1977, 21, 35 1. 25 K. R. May, N. P. Pomeroy, and S . Hibbs, J . AerosolSci., 1976, 7,53. 26 N. J . Pattenden and R. D. Wiffen, Atmos. Environ., 1977, 11,677. H. S. Chahal and D. J. Romano, J. Air Pollut. Control Assoc., 1976. 26,885. 28 L. C. Thanukos, J. A. Taylor, and R. E. Kary, J . Air Pollut. ControlAssoc., 1977, 21, 1013. l9 M.M. Benarie, Atmos. Environ., 1977, 11, 527. ” S.

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under turbulent rather than laminar air-flow conditions, that outdoor sampling can be achieved without significant distortion of the size spectrum of urban particulate matter that is collected. Special procedures are required for certain types of aerosol. Mercer 30 describes a technique for collection of sulphuric acid mist and particles emitted by copper smelters. For Saharan dust an isokinetic sampler is proposed, which is battery with an efficiency > 90% for operated and collects by electrostatic pre~ipitation,~’ most particle^.^' To separate fibrous material from spherical particulates, the aerosol can be electrically charged and separated in an electric mobility spectrometer, when fibres show high mobility.33An impingement sampler has been designed to collect salt aerosols at maritime locations or from cooling tower drift near to power stations.34 Stratospheric aerosols have been collected by balloon-borne equipment designed to impact particles on carbon or copper films for subsequent electron m i c r o ~ c o p y , ~ ~ or by direct photoelectric counting of particles in sit^.^^ Measurements by both techniques have been c~mpared.~’ Collection of large (d > 50 pm) cosmic dust particles was made by balloon-borne apparatus at an altitude of -30 km.38 Development of personal air samplers has continued and is reviewed by Wallace.39General approaches to air sampling for occupational hygiene purposes are discussed by M o l y n e ~ x A .~~ miniature prototype personal dust sampler, the ‘CIP’, is based on the annular impaction principle within a rotating housing to achieve separation into respirable and non-respirable particle^.^' Another prototype instrument relies on the particle charging principle and was originally designed for detection of fire hazard in mines by spontaneous combustion: it is adapted for continuous monitoring of submicrometre particles in ambient air and is portable.42 Two types of self-contained personal samplers are available to measure respirable and non-respirable fractions of dust in quarries.43 Filters.-The selection of filters for collection of air particulates must take into account not only collection efficiencies and effects of loading on flow rates but also interferences from metals present in the filter medium and its hygroscopic nature. These properties must be considered in relation to the objectives of the sampling ~ acetate, glass fibre, and polytetrafluoroand the method of a n a l y ~ i s .Cellulose ethylene filters showed higher efficiencies (> 99%) for ambient dust particles C. J. Mercer, ‘Proc. 4th Joint Conf. Sensing Environ. Pollutants’, Am. Chem. SOC.,Washington DC, 1978, p. 34. 3 1 B. Steen, ‘Saharan Dust’, ed. C. Morales, J. Wiley, New York, 1979, p. 279. 32 B. Steen, Atmos. Environ., 1977, 11,623. 3 3 G. Zebel, D. Hochrainer, and C. Boose, J . Aerosol Sci., 1977,8, 205. 34 B. C. Moser, ‘Cooling Tower Environment’, NTIS, Springfield, VA, 1975, p. 353. E. K. Bigg, J. A m o s . Sci., 1975, 32,910. 36 D. J. Hoffmann, J. M. Rosen, and T. J. Pepin, Rep. DOT-TSC-OST-74-15, NTTS, Springfield, VA, 1974. 37 J. L. Gras, Nature (London), 1978, 271,23 1. 38 R. Wlochowicz, C. L. Hemenway, D. S. Hallgren, and C . D. Tackett, Can. J . Phys., 1976, 54, 3 17. 39 L. Wallace, in ref. 30, p. 390. 40 M. K. Molyneux, Safety Surveyor, 1977, 5, 11. 4 1 P. Courbon, ‘Atmospheric Pollution 1978’, ed. M. M. Benarie, Elsevier, Amsterdam, 1978, p. 83. 4 2 C. D. Litton, M. Hertzberg, and L. Graybeal, in ref. 30, p. 712. 43 Health and Safety Executive, ‘Airborne Dust in Quarries’, H.M.S.O., London, 1976. 30

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Inorganic Particulate Matter in the Atmosphere

5

than nucleopore (0.8 pm) and Whatman 41 cellulose filters, which were 72% and 64% efficient at a face velocity of 49 cm s - ’ . ~Although ~ the collection efficiency of cellulose fibre filters increases markedly with loading, other types of filter are preferred for retention of Pb in urban aerosol if only light loadings are c o l l e ~ t e d .In ~ ~fact, Whatman 1 and 40 grade cellulose filters approached 100% efficiency after 24 hours collection of the ambient aerosol at Stevenage, UK,46but this was dependent on particle size and face velocity. In the Cleveland USA environment, a side-by-side comparison of total suspended particulate retained by Whatman 41 cellulose filters with glass fibre filters showed no difference at 16 sampling sites operated for 13 months.47 The collection of aerosols by nuclepore filters has been reviewed by M a n t ~ n ~ * * ~ ~ with respect to impaction, interception at the pore orifice, and diffusion by Brownian motion both to the filter face and to the walls of the pores. Problems of pore clogging have been investigated by both theoretical and experimental appro ache^.^^^ 5 1 Two modes of clogging are recognized, namely uniform pore filling and cap formation, the latter being pred~minant.~’ Evaluation of four types of glass filters for high-volume air sampling revealed small differences in collection of TSP and Pb, but large variations in SO:- and NO, : catalytic oxidation of SO, and NO, on the filter surface was suspected.s2This reaction may add 64% to true SO:- levels and 5% to TSP; because filter alkalinity is implicated, use of the neutral pH quartz fibre type is advised if glass fibre must be used.53 Methods of generation of fine particle aerosols (d < 3.5 pm) for research and calibration purposes are the subject of a symposium-revie~.~~ The practice of collection and storage of aerosols in aluminized mylar bags prior to analysis may lead to loss of submicrometre particles by electrostatic precipitation, but this can be alleviated by the use of antistatic agents.ss

Methods for Specific Aerosols.-Techniques for collection of sulphate aerosols prior to determination of total SO:- or sulphate species are summarized by B l ~ k k e r ,with ~ ~ a review of the behaviour of sulphates in the atmosphere. The problem of SO, conversion to SOP during sampling is insignificant if filters of PTFE microfibre or matrix are used, or alternatively, acid-treated quartz filtemS7 W. John and G . Reischl, Atmos. Environ., 1978, 12, 2015. B. Biles and J. McKellison, Atmos. Enuiron., 1975,9, 1030. 46 P. Clayton, Rep. LR 280(AP), Warren Spring Lab., Stevenage, Herts, 1978. 4’ H. E. Neustadter, S. M. Sidik, R. B. King, J. S. Fordyce, and J. C. Burr, Atmos. Environ., 1975, 9, 101. M. J. Manton, Atmos. Environ., 1978, 12, 1669. 49 M. J. Manton, Atmos. Environ., 1979, 13, 525. 5 o K . R. Spumy, J. Havlova, J. P. Lodge, E. R. Ackermann, D. C. Sheesley, and B. Wilder, Staub. Reinhalt. Luji., 1975, 35, 77. ” K. C. Fan, C. Leaseburge, Y. Hyun, and J. Gentry, Atmos. Environ., 1978, 12, 1797. 5 2 S. Witz and R. D. MacPhee, J. Air Pollut. Control Assoc., 1977, 27, 239. W. R. Pierson, R. H. Hammerle, and W. W. Brachaczek, Anal. Chem., 1976,48, 1808. J4 B. Y. H. Liu (ed.), ‘Fine Particles’, Academic Press, New York, 1975. 5 5 G . Cooper, G . Langer, and J. Rosinski, J. Appl. Meteorol., 1979, 18, 57. ” P . C. Blokker, CONCAWE Rep. 7/78, Den Haag, 1978. J 7 R. L. Tanner, R. Cederwall, R. Garber, D. Leahy, W. Marlow, R. Meyers, M. Phillips, and L. Newman, Atmos. Environ., 1977, 11, 955. 44

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The use of glass fibre filters to sample particulate NO; is beset with interferences from gaseous N compounds, mainly HONO, and NO,.58This is more serious than Of several types of filters tested for accumulation the formation of artifact of artifact NO; only a teflon type (‘Fluoropore’) gave negligible error.6o Determination of particulate and vapour-phase arsenic has been made by using a nuclepore pre-filter to retain particulate As and impregnated cellulose fibre filters to absorb As vapour; collection efficiencies were established with arsenic trioxide vapour.61 From measurements in the ambient atmosphere, most As was in the particulate form.61 A similar scheme was reported for determination of particulate and gaseous Br, C1, and I;62 low uptake of gaseous halogens by the nuclepore pre-filter is an advantage when sampling in remote continental regions where the gaseous halogens exceed particulate forms by two orders of magnitude. A sampling technique has been devised to permit collection of particulate (organic + inorganic) and volatile organic pollutants separately for analysis.63 Methods for sampling and identification of asbestos and asbestiform minerals are given by several authors at a recent Workshop.64 The UK Health and Safety Commission65 have made recommendations for monitoring asbestos dust (chrysotile, amosite, and crocidolite) in both non-occupational and workplace environments. Collection of Dry Deposition and Rainwater.-Steen 66 has summarized current techniques for measuring dry deposition of particulates from the atmosphere by direct accumulation on flat filter plates, natural surfaces, vertical deposit gauges, or open buckets of various diameter. From a theoretical examination of the British Standard Directional Dust Gauge it was concluded6’ that chemical analysis of the deposit would help to identify different sources and their strengths: the gauge is strongly directional. A method of short-term dustfall measurement was developed to study nuisance levels up to 1.2 km from a cement plant, to relate to complaints by residents: monthly operated gauges were misleading and inappropriate for this purpose.68 Rainwater is most frequently collected together with the dry deposition to the funnel, and in many cases deliberately, to represent the total (wet + dry) deposition to the ground. To exclude the dry deposition, various mechanical devices are now available that incorporate a moisture sensor to trigger exposure of the rain collector ’O Results from one such device, originally only when precipitation C. W. Spicer and P. M. Schumacher, Atmos. Enuiron., 1979, 13,543. R. W. Coutant, Environ. Sci. Technol., 1977, 11, 873. “ B. R. Appel, S. M. Wall, Y. Tokiwa, and M. Haik, Atmos. Environ., 1979, 13, 319. 6 1 P. R. Walsh, R. A. Duce, and J. L. Fasching, in ref. 9. p. 140. 6 2 K. A. Rahn, R. D. Borys, and R. A. Duce, in ref. 9, p. 172. 63 W. Cautreels and K. van Cauwenberghe, Atmos. Environ., 1978, 12, 1133. 64 C. C. Gravatt, P. D. La Fleur, and K. F. J. Heinrich, Natl. Bur. Stand. ( U S . ) ,Spec. Publ., 1978, 506. 65 Health and Safety Commission, ‘Asbestos. Measuring and Monitoring Asbestos in Air’, H.M.S.O., London, 1978. 66 B. Steen, in ref. 3 1, p. 287. 67 A. W. Bush, M. Cross, R. D. Gibson, and A. P. Owst, Atmos. Environ., 1976, 10,991. R. H. Williamson, J. H. Erkins, and A. Cantrell, in ref. 41, p. 175. 6 9 H . L. Volchok and R. T. Graveson, ‘Proc. 2nd Fed. Conf. Great Lakes’, Great Lakes Basin Commission, 1976, p. 259. D. G. Benham and K. Mellanby, Weather, 1978, 33, 151. 5n

J9

’”

Inorganic Particulate Matter in the Atmosphere

7

developed to separate wet and dry deposition of radioactive fallout71 have been obtained by operation for one year at Chilton, Oxon, with monthly sample changes72(see also Section 6, Total Deposition). Special apparatus is described to collect rainwater in forests, as throughfall and ~ t e m - f l o w . ~ ~ Total Suspended Particulates.-Standard methods for sampling and measuring total suspended particulate matter (TSP) are listed in a manual issued by the W.H.0.74 to encourage their use and thereby assist comparisons of data from worldwide networks of monitoring stations. Three methods are based on gravimetry, and employ pre-weighed glass fibre filters. They are suitable for standard 24 h sampling periods and are (i) a high-volume method with constant flow, (ii) an EPA high-volume method, constant flow not maintained, and (iii) an OECD method, modified by the British Standards Institute. Two photometric methods are described, using sampling periods from 1-24 h:74the soiling of glass fibre or cellulose filters is measured in a reflectometer. Improved accuracy in weighing particulates collected on cellulose and other filters is obtained by using a constant temperature and humidity chamber for all handling operation^.^^ Comparative studies with filter tape samplers, whereby the thickness of particulate deposit is measured by attenuation of beta-radiation, prove the value of this technique to measure short-term (3 h) concentrations of TSP.76 A semicontinuous beta-monitor (Philips 9790) has been successfully used by B e t ~ a r i e . ~ ~ Infrared extinction has been applied to measurement of aerosol mass this method requires concentration, at wavelengths between 9 and 12 knowledge of the average refractive index and mass density of particles, but extinction is independent of particle size distribution at the selected wavelengths. Measurement of Particle Size.-Various aspects of particle size analysis are presented in a series of conference papers, which includes a description of standard particulate reference materials for checking and calibration purposes.78 Determination of particle-size distributions by impactor devices is reviewed by S h a ~ . ~ ~ Operational difficulties with high-volume cascade impactors occur mainly from particle bounce effects that cause displacement from the impaction surface to the smaller size stages of the collector.80-82Modifications to the design of cascade impactors to improve performance have been proposed and tested.83 Wangens4

’I

R. S. Cambray, E. M. R. Fisher, L. Salmon, and W. L. Brooks, AERE Harwell Report R 5898,

H.M.S.O., London, 1970. P. A. Cawse, ‘Inorganic Pollution and Agriculture’, H.M.S.O., London, 1980, p. 22. 7 3 J. D. Miller and H. G. Miller, Lab. Practice, 1976, 25, 850. 74 W.H.O., ‘Selected Methods of Measuring Air Pollutants’, World Health Organisation, Geneva, 1976. 7s J. Strand, T. Stolzenberg, and A. W. Andren, Atrnos. Environ., 1978. 12. 2027. 76 S. Dalager, Atrnos. Environ., 1975, 9, 687. 77 P. Chylek, J. T. Kiehland, and M. K. W. KO, Atmos. Enniron., 1979, 13, 169. 7 8 M. J. Groves, ‘Particle Size Analysis’, Heylen, London, 1978. 79 D. T. Shaw, ‘Fundamentals of Aerosol Science’, J. Wiley, New York, 1978. T. Allen, ‘Particle Size Measurement’, 2nd Edn., Chapman and Hall, London, 1975. P. R. Walsh, K. A. Rahn, and R. A. Duce, Atrnos. Environ., 1978, 12, 1793. 82 A . K. Rao and K. T. Whitby, J . Aerosol Sci., 1978,9, 77. 83 G. J. Newton, 0. G. Raabe, and B. V . Mokler, J . Aerosol Sci., 1977,8, 339. 84 L. E. Wangen, J . Air Pollut. Control Assoc., 1978, 28, 5 5 . 72

Environmental Chemistry

8

coated nuclepore (polycarbonate) filters with grease to reduce particle bounce on impaction and obtained a multi-element analysis of the particulates without interferences except for C1 and Cr. Investigations on bounce-off and wall-loss of fly ash particles sampled by a seven-stage impactor are reported;85the use of scanning electron microscopy to confirm impactor sizing data is advised, particularly for particles collected on the final ‘backup’ filter. Alterations to the sampler inlet and stages of an Andersen cascade impactor are described 86 that improve the collection of larger particles by reducing the effects of wind and turbulence, and reduce wall losses from 32% to 9% for test particles of 10 ,um diameter. A cascade quartz crystal microbalance has been used to measure the size The crystal micdistribution of particulates from a rocket exhaust robalance is basically a cascade impactor with a piezo-electric crystal as an impinging surface.88A decrease in resonant frequency occurs as the deposited mass increases and subsequently, scanning electron microscopy may be carried out on particles adhering to the face of the crystals. The great sensitivity of this instrument means that a sampling time of 6 min is adequate at TSP loadings of 50-100 ,ug m-3

89

As an alternative to cascade impactors, centrifugal particle-size separators (cyclones) have been adapted to high-volume measurements, with continuous operation for a week in urban atmospheres to obtain five size fractions.90 For measurement of specific particle-size ranges, the application of inertial, diffusion, optical, and electrical methods, and statistical treatment of data are the subject of recent b o o k ~ . ’ *The * ~cloud ~ ~ ~condensation ~ nucleus (CCN) fraction of TSP has been measured by a real-time aircraft borne detector to evaluate the effect A modified of CCN (d = 0.01-1 ,um) on cloud microstrilcture and precipitati~n.~~ Aitken nucleus (AN) counter that will operate automatically has been developed for the NASA Global Atmospheric Sampling Programme: it can detect particle - ~has’been used at flight altitudes between 6 and concentrations of < 10 AN ~ m and 13 km.93 The instrument is calibrated against a Pollak (photoelectric nucleus) counter. The integrating nephelometer can provide continuous measurement of particle mass in the accumulation mode, within the size range 0.1-2 pm, by relating light scattering to TSP.94p9 5 In the Chicago environment the light scattering coefficient was highly correlated with particulate weights in the size range 0.38-1.3 ,um obtained by cascade impactor, and was independent of humidity.96 The nephelometer is suited to short-term measurements of peak concentrations of airborne

particulate^.^^ J. M. Ondov, R. C. Ragaini, and A. H. Biermann, Atmos. Environ., 1978, 12, 1175. A. R. McFarland, J. B. Wedding, and J. E. Cermak, Armos. Environ., 1977, 11, 535. 87 R. L. Chuan and D. C. Woods, in ref. 30, p. 610. 88 J. R. McNesby, ‘Proc. Int. Symp. Recent Advances in Assessment of Health Effects of Environmental Pollution’, Rep. EUR 5360, C.E.C., Luxembourg, 1975, p. 1371. 89 R. L. Chuan, in ref. 54, p. 763. 90 D. M. Bernstein, M. T. Kleinman, T. J. Kneip, T. L. Chan, and M. Lippmann, J . Air Pollut. Control Assoc., 1976, 26, 1069. 91 R. D. Cadle, ‘The Measurement of Airborne Particles’, J. Wiley, New York, 1975. 92 V. K. Saxena and N. Fukuta, ‘Proc. Int. Conf. Cloud Phys.’, Boulder, CO, 1976, p. 607. 93 T. W. Nyland, N.A.S.A. Tech. Paper 1415, 1979. 94 A. G . Clarke, M. A. Moghadissi, and A. Williams, J . Aerosol Sci., 1977, 8, 73. 8s 86

Inorganic Particulate Matter in the Atmosphere

9

Separate collection of non-respirable and respirable fractions of ‘I’SP suitable for elemental analysis has been achieved by using two nuclepore filters in series, with pore diameters of 12 pm and 0.2 pm, respectively, at 12.7 cm s-’ face velocity for acceptable collection effi~iency.~’ Coarse and fine fractions of the TSP have been collected by a two-stage impactor suitable for on-line measurements, based on the beta-attenuation principle.98 The ‘anthropogenic’ fraction of TSP has been derived from analysis of air-filter deposits for C1 and Si to eliminate the contribution from soil dust, and is claimed to show better correlation with public concern and reduction in v i ~ i b i l i t y . ~ ~ Continuous measurement of carbonaceous particles is reported using a spectrophone to measure their light absorption.Io0 The absorption coefficient for aerosols of graphitic carbon type (rather than natural ‘organic’ type) is 17 m2 g-’ carbon at 416.6 nm, employing a helium-cadmium laser source.1ooSizing of single particles by laser interferometry using a cross beam laser velocimeter is described by Roberds,lo1and relies on forward scattering of light by the particle to obtain size information by means of data-inversion methods. lo2 Submicrometre particle size distributions have been determined by application of three continuous integral aerosol sensors, namely a condensation nucleus counter, an electrical aerosol charger, and an integrating nephelometer to measure the number, surface, and volume parameters of the aeros01.l~~ The authors apply a special data-inversion procedure to derive the particle-size distribution. Subsequently, this method was used to study power station plumes.’o4 Recent types of Knollenberg (light scattering) aerosol counters have been evaluated with monodisperse test aerosols in the size range 0.1-10 pm, with the conclusion that resolution was poor for particles >0.5 pm radius.lo5 Other laboratory and field tests on optical particle counters indicated that frequent calibration is necessary, but agreement was generally good for submicrometre particles.lo6Ilo’ Calibration in the field is possible with a specially designed inertial impactor. lo* A particle-size spectrometer supplemented by a microcomputer can obtain a differential size distribution for the ambient aerosol over 19 intervals of equal logarithmic size from 0.3-11 pm diameter, with the option to select a number, surface, or volume representation.lo9 J. C. Kretzschrnar, Atmos. Environ., 1975, 19, 931. P. A. Scheff and R. A. Wadden. Atmos. Environ., 1979. 13,639. 97 R . D. Parker, G. H. Buzzard, T. G . Dzubay, and J. P. Bell, Atmos. Environ., 1977, 11,617. 98 E. S. Macias and R. B. Husar, ‘Proc. 2nd Int. Conf. Nucl. Methods Environ. Res.’, J. R. Vogt and W. Meyer (ed.), Univ. Missouri, 1974, p. 4 13. 9’) D. A. Levaggi, J . S. Sandberg, M. Feldstein, and S. Twiss, J. Air Pollut. Control Assoc., 1976, 26, 554. T. J. Truex and J. E. Anderson, Atmos. Environ., 1979, 13, 507. ‘‘I D. W. Roberds, Appl. Optics, 1977, 16, 1861. A. L. Fymat, in ref. 30, p. 7 19. G. M. Sverdrup and K. T. Whitby, Environ. Sci. Techno[.,1977, 11, 117 1. lo4 G. M. Sverdrup, Atmos. Environ., 1978, 12, 2005. Io5 R. G. Pinnick and H. J. Auvermann, J. Aerosol Sci., 1979, 10,55. ‘06 E. E. Hindman, G . L. Trusty, J . G. Hudson, J . W. Fitzgerald, and C. F. Rogers, Atmos. Environ., 1978, 12, 1195. lo’ J . Kruger and A. H. Leuschner, Atmos. Enoiron., 1978, 12, 201 1. V . A. Marple and K. L. Rubow, J. Aerosol Sci., 1976, 7,425. lo’) C. W. Lewis and P. J. Lamothe, J. Aerosol Sci.,1978, 9, 39 1. 95

96

Environmental Chemistry

10

Analysis of particle size and shape by holography has been further developed by introduction of new systems for automatic analysis of three-dimensional aerosol images, to overcome tedious manual recording Determination of Atmospheric Turbidity.-Measurement of the integrated aerosol content of the atmosphere has been made for many years by sun photometers and pyrheliometers. A new sun photometer is now proposed to improve reliability, and typical errors experienced with current apparatus using 380 nm and 500 nm filters are summarized.112It is recognized that the pyrheliometric method is the most stable and is best for recording low turbidities at baseline stations."* Several types of sun photometers were intercalibrated and applied to measurement of dust in the Saharan air layer over the N. Atlantic ocean: the turbidity data was examined in relation to mineral and sea salt components of particulates collected on air filters at ground l e ~ e 1 . lSahara ~~ dust episodes at Monte Cimone and Sestola, Italy, have been measured with Volz sun photometers operated at four wavelength intervals, and related to particle-size spectra at ground level.114The authors conclude that the large particle mode (radii 0.3-1.2 pm) is mainly responsible for wide variations in optical thickness of the atmosphere. Relationships between the physical properties of the atmosphere and the angular and total scattering of light by haze aerosols are reported by McCa~tney."~ A valuable list of measurements of scattering in the free atmosphere is classified into optical probing, contrast and visibility, and day sky radiance.'I5 Remote Sensing of the Atmosphere.-Satellites have been used to observe the source and trajectories of haze, soil dust, volcanic debris, factory plumes, and smoke from forest fires. The geostationary orbiting satellites (SMS/GOES system) operated by the US National Oceanic and Atmospheric Administration provide visible imagery and infrared data, and Parmenter116 describes results from two satellites operating over the equator at 135O W and 75 OW. Studies of smoke plumes by the general purpose LANDSAT-1 satellite can cover a large area of country in great detail, with a resolution of -70 m.117*'18 Differences in absorption by aerosol in the plumes are detected by a multi-spectral scanner that operates over four wavebands."' LANDSAT images of the UK have been analysed at the University of East Anglia;Il8 problems of distinguishing plumes from clouds have received special attention. Developments in high-power tunable lasers covering the range -400-40 pm have led to increasing application to optical spectroscopy for monitoring both

I"

R. Bexon, J. Gibb, and G. D. Bishop, J. Aerosol Sci.,1976, 7, 397. J. D. Trolinger, U.S. Environ. Prot. Agency Rept 600/2-79/005. 1979.

lI3

J. M. Prospero, D. L. Savoie, T. N. Carlson, and R. T. Nees, 'Proc. 1 Ith Tech. Conf. Hurricanes and

'lo

C. Frohlich, in ref. 9, p. 12 and p. 89.

'I4 'I5 'I6 11' ll*

Tropical Meteorol.', Am. Meteorol. SOC.,Boston, MA., 1978, p. 163. C. Tomasi, F. Prodi, and F. Tampieri, Beit. Physik. Atmos., 1979, 52, 215. E. J . McCartney, 'Optics of the Atmosphere-Scattering by Molecules and Particles', J. Wiley, New York, 1976. F. C. Parmenter, in ref. 30, p. 254. T. T. Alfoldi, in ref. 30, p. 258. P. Brimblecomhe, A. Armstrong, and T. Davies,J. Br. Interplaner. Soc., 1978, 31, 11.

Inorganic Particulate Matter in the Atmosphere

11

particulate and gaseous pollutants.119 An airborne down-looking lidar (light detection and ranging) is advantageous for research on plume dispersion. l Z o Zuev”’ refers to two simultaneously operating lidars, one ground based and the other airborne, to record vertical profiles of the volume backscattering and total scattering co-efficients and their ratio (lidar ratio value). Heighthime cross-sections of the aerosol over Munich have been recorded by an airborne Nd-glass laser at 1.06 A mobile ground-based ruby laser radar unit has been developed for particulate dispersion measurements. lZ3 Basic principles of measurements by lidar and the ‘DIAL’ system (differential absorption lidar), which employs a pulsed tunable laser source to obtain long path absorption data, are discussed by Svanberg. lz4 Remote sensing and characterization (complex refractive index and size distribution) of stratospheric aerosols by lidar, by a dustsonde (balloon-borne optical counter), and by satellite-borne photometer have been discussed at a recent Workshop.125Temporal and spatial variations in the stratospheric aerosol detected by lidar are shown to respond to meteorological influences and extension of this technique to observe stratospheric-tropospheric interchange of aerosols is proposed. 126 With a ground-based ruby lidar system, the backscattering from aerosols is obtained by comparing the total backscattering profile with the expected return from the dominant molecular component in the atmosphere. 127.128 Fluctuations in the stratospheric aerosol load from 1970- 1977 are discussed with special reference to particles of volcanic and extra-terrestrial origin,lZ9as observed by lidar. Iwasaka 130 used a two-colour lidar at A 0.6943 pm and 1.06 pm to record the size distribution function and density of stratospheric aerosols with 0.1-1 Fm radii, assuming a refractive index of 1.42; since the measurement time is short, about 100 s, changes in vertical profiles caused by atmospheric processes can be km altitude), the existence of aerosol studied. In the mesosphere (from -50-60 layers containing N a and K are confirmed by fluorescence lidar.’31*’32 Microscopy of Dusts and Fibres.-Combinations of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence, and

C. K. N. Patel, Science, 1978, 202, 157. A. Eckert and R. B. Evans, ‘Proc. 1 lth Symp. Remote Sensing Environ.’, Ann Arbor, MI, 1977, p.

I2O J.

353.

V. E. Zuev, Dev. Atmos. Sci., 1978, 9, 265. C. Werner, G. S. Kent, and F. Kopp, ‘Proc. 4th Symp. Meteorol. Obs. Instrum.’, Am. Meteorol. SOC., Boston, Mass, 1978, p. 197. 12’ R. M. Hoff and F. A. Froude, Atmos. Environ., 1979, 13,35. l z 4 S. Svanberg, ‘Surveillance of Environmental Pollution and Resources by Electromagnetic Waves’. ed. T. Lund, D. Reidel, Dordrecht, Holland, 1978, p. 37. 1 2 5 A. Deepak (ed.), ‘Inversion Methods in Atmospheric Remote Sounding’, Academic Press. New York. I2l

122

1977.

F. G. Fernald and B. G. Schuster, J. Geophys. Res., 1977, 82,433. 12’ P. B. Russell, V. Viezee, R. D. Hake, and R. T. H. Collis, Q.J.R. Meteorol. Soc.. 1976, 102,675. 128 R. Reiter, H. Jaeger, W. Carnuth, and M. Littfass, Dev. Atrnos. Sci., 1978, 9, 277. 129 B. R. Clemesha and D. M. Simonich, J . Geophys. Res., 1978, 83, 2403. Y. Iwasaka, J . Meteorol. SOC.Jpn., 1977, 55,457. G. Megie, F. Bos., J. E. Blamont, and M. L. Chanin, Planet. Space Sci., 1978, 26, 21. 132 B. R. Clemesha, V. W. J. H. Kirchoff, and D. M. Simonich. Planet. Space Sci., 1979, 27, 909. lz6

12

Environmental Chemistry

diffraction analysis have been developed to give valuable information on the depth and surface properties of particles that facilitates identification of sources.133-136 For analysis of fly ash particles, combination of SEM with energy dispersive X-ray analysis (EDXRFA) provides simultaneous colour mapping to show the spatial distribution of Ca, Fe, and K ; some 100 particles can be scanned in 3 min.I3' A similar technique was used to analyse dust particles in pulmonary tissues for Al, Ca, Fe, Mg, S, Si, and Ti.138Combination of SEM with X-ray diffraction analysis of Sahara dust enabled distinction between clay and quartz particles of diameter 0.08-7 Other applications of SEM and EDXRFA have been made to analysis of particulates collected by a piezoelectric cascade impactor, during aircraft sampling of rocket exhaust87 and volcanic plumes.140 Distinct morphological and chemical differences are related to particle size fractions. Thus in volcanic-derived aerosols impure sulphuric acid droplets were seen with some large crystals rich in A1 and Zn, and fragments of basaltic glass and p l a g i o ~ l a s e . ' ~ ~ Studies on Antarctic aerosols utilized the resolution obtained by TEM photographs for counting and sizing purposes.141X-Ray energy spectra showed that over 50% of Aitken particles (d < 0.2 pm) contained A1 and S, 35% contained Si, but few trace elements which were predominant in larger parti~1es.I~~ Particulates scavenged by snow and rain and deposited on coniferous trees have been characterized by TEM, SEM, and EDXRFA, with aggregates of small soot particles best observed by TEM.'42 Gonzales and Murr143developed a TEM method to examine particulates scavenged by single raindrops, and demonstrated that in New Mexico these particles are mainly polycrystalline aggregates of layer silicates from 0.0 1-3 pm in diameter. Quantitative analysis of SO:- in individual particles from 0.01 ,um to a few micrometers diameter is possible by collecting them on electron microscope screens and coating with BaCI,, after which the growth rings of BaSO, are recorded by TEM.144v145 A similar technique has been used to analyse non-volatile nitrates in particles >0.2 pm diameter, by reaction with nitron reagent to produce needles surrounding the particles. 146 Many improvements have been made to methods for sampling, analysis, and '~~ identification of asbestos fibres by TEM, SEM, and X-ray s p e c t r ~ m e t r y . Fibre counting and size measurements from SEM can be related to analysis of elements, H. Malissa and M. Grasserbauer, Mikrochim. Acta, 1975, No. 2,325. L. D. Hulett, H. W. Dunn, J . M. Dale, J . F. Emery, W. S. Lyon, and P. S. Murty, 'Measurement Detection and Control of Environmental Pollutants', I.A.E.A., Vienna, 1976, p. 29. R. W. Linton, P. Williams, C. A. Evans, and D. F. S . Natusch, Anal. Chem., 1977, 49, 15 14. 1 3 6 F. Parungo, E. Ackerman, H . Proulx. and R. Pueschel, Atmos. Environ., 1978, 12,929. J. B. Pawley and G . L. Fisher, J . Microsc., 1977, 110, 87. 1 3 8 A. Brody, N. V. Vallyathan, and J. E. Craighead, 'Scanning Electron Microscopy', Pt. 3, I.I.T. Research Inst., Chicago, IL., 1976, 9,477. F. Prodi and G . Fea, J . Geophys. Res., 1979,84,6951. I4"R. D. Cadle, A. L. Lazrus, B. J. Huebert, L. E. Heidt, W. 1. Rose, D. C. Woods, R. L. Chuan, R. E. Stoiber, D. B. Smith, and R. A. Zielinski, J . Geophys. Res., 1979,84,6961. I 4 l F. Parungo, E. Ackerman, W. Caldwell, and H. K. Weickmann, Tellus, 1979, 31, 521. 14* J. Gether, G. Lunde, and J. Markali, SNSF Project Res. Rep. FR 7/76, Nisk, Norway, 1976. ' 4 3 T. W. Gonzales and L. E. Murr, J . Geophys. Res., 1977, 82, 3161. 144 Y. Mamane and R. G. de Pena, Atmos. Environ., 1978, 12,69. 14' G. P. Ayers. Atmos. Environ., 1978, 12, 16 13. 146 G. P. Ayers, Atmos. Environ., 1978, 12, 1227. '41 I. J. Selikoff and D. H. K. Lee, 'Asbestos and Disease', Academic Press, New York, 1978. 13'

134

Inorganic Particulate Matter in the A tmosphere

13

e.g., Al, Ca, Fe, Mg, Na, and Si,148,149 and inter-element ratios assist identification of the main form of asbestos. In a recent comprehensive review of SEM and TEM methods applied to fibrous particles that occur in ambient air, an informative series of scanning electron micrographs is shown which includes ammonium sulphate and gypsum particles in addition to glass and asbestos Nuclepore filters of different pore diameters are preferred for sampling prior to SEM, to partially separate asbestos from larger non-fibrous particles.150 De Nee151 reported improvements in back-scattered electron imagery with SEM that can reveal asbestos microfibres of higher atomic number than organic material in the filter or lung tissue matrix. A computerized SEM system combines image analysis of fibres with EDXRFA of their chemical composition, to identify asbestos fibres from other particulate matter.ls2 The detailed particle atlas by McCrone and Delly 153 provides a unique collection of photomicrographs to assist in characterization of airborne materials from observations with SEM, TEM, and the polarizing microscope. Biological Sampling and Monitoring Techniques.-Examination of relative levels of particulate metals in the atmosphere and input to the ground by the use of plants as bioindicators and collectors has continued, often with bioassay of phytotoxic gaseous pollutant^.'^^ Apart from analysis of the indigenous flora such as epiphytic bryophytes,ls5 test plants may be exposed over definite periods (transplant technique). This method is required in many areas where pollution has eliminated the local flora. Lichens are attractive as indicator plants and the value of various species and their identification has been reviewed.lS6 Characteristics of species with respect to selective uptake of metals must be recognized, in addition to the possibility of heavy metal toxicity that could result in threshold levels for metal intake by the thalli.157 Lead concentrations in native lichens (Hypogyrnnia physodes) growing close to a motorway were one third of levels in the substrate which was bark of Pinus syluestris, and in this case it was concluded that bark sampling was a better indicator of pollution by motor vehicles up to 200 m from the road.lS8 Air pollution from metal industry at Kokkola, Finland was best indicated by accumulation of Fe, S, and Zn in indigenous epiphytic bark lichens and Zn in pine needles, but increases in V in lichens were attributed to emissions from fuel oil combustion. 159 In a subsequent study of emissions from wood pulping industry, native lichens were K. R. Spurny and W. Stober, ‘Proc. 3rd Int. Conf. Nuclear Methods Environ. Energy Res.’, USERDA, Columbia, Missouri, 1977, p. 69. 149 K. R. Spurny, W. Stober, H. Opiela, and G. Weiss, Sci. Total Environ., 1979, 11, 1. K. R. Spurny, W. Stober, E. R. Ackerman, J. P. Lodge, and K. Spurny, J. Air Pollut. Control Assoc., 1976, 26,496. P. B. De Nee, ‘Symp. Electron Microscopy of Microfibres’, M. Asher and P. P. McGrath (ed.), U.S.F.D.A., Rockville, MD, 1977, p. 68. I5*T. Werlefors, C. Eskilsson, S. Ekelund, S. Krantz, and C. Tillman, ‘Proc. Int. Symp. Control Air Pollut. Work. Environ., Stockholm, 1978, p. 255. 153 W. C. McCrone and J. G. Delly, ‘The Particle Atlas’, 2nd Edn., Ann Arbor, MI, 1973, Vol. 1 - 4 . 154 W. A. Feder, Environ. Health Perspect., 1978, 21, 139. L. Rasmussen, Environ. Pollut., 1977, 14, 37. D. L. Hawksworth and F. Rose, ‘Lichens as Pollution Monitors’, E. Arnold, London, 1976. 15’ M. R. D. Seaward, Lichenologist, 1975, 6, 158. lSB K. Laaksovirta, H. Olkkonen, and P. Alakuijala, Environ. Pollut.. 1976, 11,247. I S 9 K. Laaksovirta and H. Olkkonen, Ann. Bot. kenn., 1977, 14, 12. 14*

14

Environmental Chemistry

analysed for seven elements to indicate the distribution of pollutants, in preference to pine needles.160Atmospheric heavy metal pollution in the Copenhagen area was examined by analysis of epiphytic lichens (Lecanora conizaeoides), epigeic bryophytes (Brachythecium rutabulum and R hytidiadelphus squarrosus), bulk precipitation, and top regional differences in deposition isopleths found for Pb, V, and Zn showed good agreement for all media. Significant decreases in concentrations of Ca, F, Li, Se, Sr, and U were found in a terricolous lichen (Purmelia chlorochroa) along transects radiating up to 64 km from a fossil-fuel power station.16* Hypogymnia physodes is noted as more resistant to SO, than either Alectoria capillaris or Usnea ~ p p . ' ~ ~ The transplant technique for lichens usually involves removal on tree bark or branches, which are then mounted on a suitable base for placement in industrial regions. Steinnes and Krog'64 reported order of magnitude increases in Hg (from 0.4 p g g-I background) in Hypogymnia physodes after a month in urban conditions. In North-Rhine Westphalia, FRG, both lichen and rye-grass transplants were analysed. 165 Native mosses (Dicranellu heteromalla and Ceratodon purpureus) and grass (Holcus lunatus) contained 1240 and 130 pg Pb g-', respectively, as a result of pollution from a battery factory.166Hypnum cupressiforme growing within 14 km of Consett iron and steel complex in N.E. England contained high levels of Cu, Mn, Pb, and Zn in addition to Fe.I6' In Norway, Hylocomium splendens from rural sites showed 20-fold differences in accumulation of As, Pb, Sb, and Se that were directly related to precipitation,168and it is noted e l ~ e w h e r e that ' ~ ~ most metals present in moss originate from direct dustfall, precipitation, and stem-flow, since the chemical composition of moss and bark is very different (except for K). Hylocomium splendens from Polish National Parks accumulated more Cd and Cu, but less,Pb and Zn than Pleurozium hylocomium and patterns of regional pollution were e~tablished."~Emissions from a coal-fired power plant in Fort Union Basin, Montana led to significant accumulations of As in forage plants of the region including Agropyron spicatum and Artemisia cana, used as indicators of pollution. 1 7 1 The use of small moss bags for regional aerosol monitoring is recently reviewed.I7* These are prepared from specially cleaned moss from rural areas, and the bags are normally exposed for 1-6 weeks at 1.5-2 m above ground. After exposure, analysis may be made by atomic absorption following wet ashing in K. Laaksovirta and H. Olkkonen. Ann. Bof. Fenn., 1979, 16, 285. A. Andersen, M. F. Hovmand, and I. Johnsen, Enuiron. Polluf.. 1978, 17, 133. I b 2 L. P. Cough and J . A. Erdman. Bryologisl. 1977, 80,492. K. Laaksovirta and J. Silvola,Ann. Bot. Fenn., 1975, 12, 81. lh4 E. Steinnes and H. Krog, Oikos, 1977, 28, 160. I h 5 B. Prinz and G . Schull. Schrifl. Landes Nordrhein- Wesffalen, 1978, 46, 25. l h 6 J. M. Ratcliffe".Atrnos. Eni!iron., 1975, 9, 623. 1 6 7 G . Ellison. J . Newham. M. J. Pinchin. and 1. Thompson, Environ. Pollut., 1976, 11, 167. I h H E. Steinnes, Inst. Atomic Energy Rep. K R 154, Kjeller, Norway, 1977. l b 9 L. Rasmussen and I. Johnsen, Oikos. 1976, 27,483. K. Grodzinska, Water Air Soil Pollut., 1978. 9, 83. J. J. O'Toole. T. E. Wessels, and K. L. Malaby, Rep. IS-M-205. U.S. Dept. Energy, Office of Health and Environ. Res., 1978. G. T. Goodman. M. J. Inskip. S. Smith, G. D. R. Parry. and M. A. S. Burton. in ref. 3 I . p. 2 11. Ih"

'"

Inorganic Particulate Matter in the Atmosphere

15

HNO,. 173 Mosses have a high cation-exchange capacity, therefore leaching of metals by rainfall during exposure is minimized.172Surveys in S.W. England for metals in air particulate have been made by moss bags alone,173or in combination with air filtration and a resin-impregnated material (TAK) to retain air particulate^.'^^ Moss bag exposure was able to show unsuspected areas of metal pollution, but was difficult to relate to air concentrations from filter analysis.174A similar conclusion was reached following a combined survey in the Swansea Valley, using moss bags, air filters, and dust and rainwater C10ugh’~~ reported that deposition of particles to moss bags (Hypnurn cupressiforrne) is similar to a flat surface of rye-grass and they are useful dry deposition monitors; because the collection efficiency of moss changes rapidly with particle size and is low for submicron particles, it is less valuable for monitoring concentrations of elements in air particulate than in dry deposition. Methods of Analysis.-Advances in the application of various methods to analysis of air particulates will only be referred to in brief, since detailed discussion of this topic and methodology is made e1~ewhere.l~~. 178 Several new techniques have been applied to multielement analysis of inorganic particulate material collected from the atmosphere by filters or impactor devices. These techniques can analyse specific size fractions or individual particles from such material and provide better chemical characterization to help identify natural and industrial sources of particulates in the ambient atmosphere. For example, X-ray fluorescence (XRF) analysis of trace elements has been aided by developments in semiconductor detectors. This has led to increasing application of energy dispersive X R F analysis with excitation of photons by X-rays,’79 or by bombardment of air-filter deposits with 3-5 MeV protons (particle-induced X-ray emission: ‘PIXE’). lso> Proton elastic scattering analysis (‘PESA’), using higher energy protons than PIXE, has been applied where light elements are of main concern e.g., from F to S, and reduces problems of attenuation of soft x-ray^.'^*,'^^ The sensitivity of automated energy dispersive X R F permits multielement analysis of filters exposed on high-volume air samplers for only 10-20 h.ls4 Minimum detectable limits are reported in the range 2.5-8 ng cm-’ filter for As, Br, Cd, Cu, Ga, Hg, Ni, Pb, Rb, Sb, Se, Sn, Sr, and ZII.”~ BirksIs5 concludes that energy dispersion methods are more suited to general element surveys in unfamiliar samples, while wavelength R. Gill, M. H. Martin, G. Nickless, and T. L. Shaw, Chemosphere, 1975,4, 113. L. E. Robson, ‘A Survey of Airborne Metals’, Rept. Avon Glos. Somerset Environ. Monitoring Ctee., Bath, 1977. L. E. Robson, ‘Rept. Collab. Study on Certain Elements in Air, Soil, Plants, Animals and Humans in the Swansea-Neath-Port Talbot Area’, Welsh Office, Cardiff, 1975. 1 7 6 W. S. Clough, Atmos. Environ., 1975, 9. 11 13. H. Malissa (ed.), ‘Analysis of Airborne Particles by Physical Methods’, C R C Press, Boca Raton, FL, 1978. M. Katz, J . Air Pollut. ControlAssoc., 1980, 30, 528. J. M. Jaklevic, R. C. Gatti, F. S. Goulding, B. W. Loo, and A. Thompson, in ref. 30, p. 697. T. B. Johansson, M. Ahlberg, R. Akselsson, G. Johansson. and K. Malmqvist, J . Radioanal. Chem., 1976. 32, 207. “ I J. W. Winchester, in ref. 148, p. 1. K. Kemp, in ref. 41, p. 57. J. W. Nelson, in ref. 186, p. 19. In4 P. Van Espen. H. Nullens, and F. C. Adams, Z . Anal. Chem., 1977,285,215. L. S. Birks, in ref. 186, p. 57. 174

”’

16

Environmental Chemistry

dispersion achieves better resolution of elements and is appropriate for routine analysis of large numbers of samples; it can also distinguish the valence and bonding of elements such as S present as sulphate, sulphite, and sulphide compounds. Problems associated with preparation of thin layer standards to calibrate X R F techniques and corrections for attenuation have been reviewed by Dzubay.lg6 Analysis of individual particles of fly ash has been made by ion microprobe mass spectrometry and auger electron spectrometry to reveal the surface predominance of Cr, Mn, Pb, and TI, which is explained by a volatilization-condensation mechanism.135The application of emission spectrographic methods to multielement analysis of air particulates is reviewed by Skogerboe.lg7With this procedure, porous cup graphite electrodes may be used as air filters and are very suitable for short sampling periods of 4-1 h in urban areas, to follow the time variation of element concentrations.I g 7 Neutron-activation analysis has been widely applied to measure some 30 to 40 elements in air p a r t i c ~ l a t e . ' ~Re ~ -cent ~ ~ ~developments include cyclic activation, using a series of neutron irradiation-transfer-count-return to irradiation system steps to allow detection of short-lived isotopes such as 207mPb(0.8 s half-life), 20F, and 77mSe.191.192 Analysis of B in addition to other elements is achieved by measurement of prompt gamma-ray emission during neutron a ~ t i v a t i 0 n . lSome ~~ laboratories have used gamma photon activation analysis to include Bi, Sn, Pb, and Zr in the suite of elements a n a 1 y ~ e d . l ~ ~ An X-ray diffraction technique can detect microgram quantities of chrysotile asbestos in respirable Infrared spectrometry has been applied to analysis of quartz dust 196 and asbestos minerals in air particulate^.'^^ Differential thermal analysis offers specific measurement of free crystalline quartz in respirable dust that contains clay minerals, as frequently collected by personal air samplers.198 For characterization of particulates from a polluted atmosphere, the use of raman spectra has been examined between 920 and 1950 ~ m - ' ; ' distinctive ~~ spectra are given by (NH,),SO,, NH,HSO,, and H,$O,, and primary particulate carbon from vehicle exhaust. However, a large fluorescence background limits general sensitivity. Newmanzoo has reviewed current methods for analysis of sulphur compounds in the atmosphere, including laser raman spectroscopy.

T. G . Dzubay (ed.),'X-ray Fluorescence Analysis of Environmental Samples', Ann Arbor, MI, 1977. R. K. Skogerboe, in ref. 23, p. 791. Ia8 L. Salmon, AERE Harwell Report R 7859, H.M.S.O., London, 1975. la9 J . Radioanal. Chem. 1977, 37, Part 2. 190 S. Amiel (ed.), 'Nondestructive Activation Analysis', Elsevier, Amsterdam, 1980. 1 9 1 N. M. Spyrou, P. Maheswaran, K. Nagy, and F. Ozek, in ref. 134, p. 15 I. I P 2 N. M. Spyrou and S. A, Kerr, J . Radioanal. Chem., 1979,48, 169. 193 G . E. Gordon, D. L. Anderson, M. P. Failey, W. H. Zoller, W. B. Walters, and R. M. Lindstrom, in ref. 148, p. 83. 194 J. S. Hislop and D. R. Williams, J . Radioanal. Chem., 1973, 16, 329. 195 B. A. Lange and J . C . Haartz, Anal. Chem., 1979,51,520. 196 J. P. Coates, Am. Lab., 1977, 9, 105. I y 7 J. P. Coates, Am. Lab., 1977, 9, 57. 198 J. P. Schelz, Thermochirn. Acta, 1976, 15, 17. 199 H. Rosen, A. D. A. Hansen, and T. Novakov, in ref. 30, p. 703. 2uo L. Newman, A m o s . Environ., 1978, 12, 113.

Ia6

la'

Inorganic Particulate Matter in the Atmosphere

17

Continuous in situ measurement of sulphur aerosols is now possible by flame photometry with separate determination of H,SO, and its ammonium salts.201,202 Many laboratories without extensive analytical facilities require simple methods of analysis for limited investigations. A laboratory manual compiled by SCOPE 203 describes sampling and analysis of several particulate metals in air, avoiding sophisticated techniques. Further practical details are available in the book by K a t ~Eleven . ~ ~ particulate ~ metals collected on polycarbonate membrane filters have been determined by atomic absorption spectroscopy.20sA new colorimetric method for analysis of microgram amounts of SO:- in water extracts from air filters is reported, using barium-nitrosulphonazo(m) chelate.*06 To establish the accuracy of reported results, intercomparison of trace element analysis by different techniques has been made at 21 laboratories by distribution of simulated (spiked) air filter samples:207results for Hg and Mo were particularly divergent. The NBS standard fly ash reference material (SRM-1633) has now been supplemented by SRM- 1648, urban particulate matter, certified for 9 elements, which was collected from the St. Louis, Missouri, urban atmosphere.208A reference material has recently been prepared by the E.E.C. Community Bureau of Reference using air particulates collected from industrial regions of Belgium. Intercomparison of analysis of filter deposits by separate techniques showed that variability was least for As, Co, Pb, and Se, intermediate for Cr, Cu, Fe, Mn, Ni, and Zn, and largest for Cd; problems of incomplete dissolution of Cr, Fe, and Ni by wet ashing were

3 General Physical and Chemical Composition of Particulates Background Aerosols.-Research on background concentrations of aerosols in the troposphere and their composition has proceeded in several remote regions, where little interference from industrial sources is anticipated. Although it is possible to talk in broad terms of continental and maritime background aerosols in addition to rural background measurements that are often used to compare with urban pollution,210natural sources may cause wide variations in regional backgrounds and make the siting of background stations and assessment of anthropogenic influences difficult.211 The chemical composition of the aerosol near the Amundsen-Scott South Pole Station212is shown in Table 1, together with concentrations observed at other

J . J. Huntzicker, R. S. Hoffman, and C. S . Ling, Atmos. Environ., 1978, 12,83. W. G. Cobourn, R. B. Husar, and J. D. Husar, A m o s . Enuiron., 1978, 12, 89. 203 SCOPE 6, 'Environmental Pollutants, Selected Analytical Methods', Butterworth, London, 1975. 204 M. Katz (ed.), 'Methods of Air Sampling and Analysis', 2nd Edn.. Am. Publ. Health Assoc., Washington, DC, 1977. 205 B. C. Begnoche and T. H . Risby, Anal. Chem., 1975,47, 1041. *06 E. M. Hoffer, E. L. Kothny, and B. R. Appel, Amos. Environ.. 1979, 13, 303. '07 A. Tugsavul, R. Dybczynski, and 0. Suschny, Environ. Int., 1979, 2, 19. 'On Anon, Dimensions, 1979, 63, 19. '09 P. A. Cawse, AERE Harwell Report R 8191, H.M.S.O., London, 1976. 2'o P. A. Cawse, AERE Harwell Report R 9164, H.M.S.O., London, 1978. 2 1 ' E. S. Selezneva, Sou. Meteorol. Hydrol., 1978, 1, 3 1. 'I2 W. Maenhaut and W. H. Zoller, J. Radioanal. Chem., 1977, 37. 637.

202

Environmental Chemistry

18

Table 1 Concentrations of elements in air at remote locations and in urban areas (ng kg-I air)* Element

Collafirth, Jundrau , Shetland Is., UK. Central Europe. Maritime Inland background * l o background * I 5 42 A1 43 0.19 <0.3 As 1.1 6.7 Br 200 Ca 0.4 <0.8 Cd Ce 0.079 2100 5.9 CI 0.037 0.040 co 0.29 (0.2 Cr 0.0 18 0.0 12 cs 0.72 cu < 12 29 40 Fe (0.0 1 0.024 Hg 0.22 I (1 0.0008 In (0.02 16 1100 K 240 8.2 Mg 1.2 1.8 Mn 0.24 (0.3 Mo 1200 18 Na Ni (2 11 Pb 3.6 0.16 Sb 0.24 0.0063 0.010 sc Se 0.3 1 0.034 Ti 2.0 < 12 0.24 V 1.3 8.1 6.5 Zn

* 1 m3 air at

Urban

Background S . Pole. Remote sire *

*

0.6 7 0.006 1.1 0.40

20 sites average in UK 2'9 6.4 __

Centra1 S wanseaZ2O S. Wales 3 70 15 3 20

-

-

-

2.8

2.1

-

-

1.4 14

0.80 4600 4.5 6.1 0.27 57 940

(0.03 0.024 0.5 1 -

0.068 -

0.56 0.59

-

-

19 6 80 -

-

-

-

-

(0.7 -

-

31

-

-

-

2.7

-

-

13 340 7.3

1960 66 5 00 4.0 0.16 2.7

-

-

0.005 (3.08 -

0.027

-

-

39 17 260

25

-

21 3 10

15 O C , 760 mm Hg (Standard Cubic Metre) = 1.226 kg.

remote and urban locations. Hogan213 found particle concentrations of 50- 100 cm-3 with geometric mean radius from 10-15 nm in the Antarctic during summer, but order of magnitude increases in concentration of very small particles occurred, possibly from subsiding air, when the tropopause height lowered to 380 mb. Element concentrations that are recorded in remote polar regions must be accounted for in terms of long-distance transport from crustal weathering, sea salt, volcanic activity, or anthropogenic s o ~ r c e s . ~ ~ * * ~ ~ ~ In central Europe, background aerosols have been studied at mountain observatories on the Jungfraujoch * I 5 (Table 1) and Zugspitze peak near

A. W. Hogan, J . Appl. Mcteorol.. 1975, 14. 550. R. A. Duce. G. L. Hoffmann, and W. H . Zoller. Science. 1975. 187,59. ' I 5 R. Dams and J. de Jonge, AImos. Enriron., 1976, 10. 1079.

213

19

Inorganic Particulate Matter in the Atmosphere

loooor

1loOo0

1

0 C .c F

a C, I 0;

0

1 1213141112131411 1213141112131411 12l3141112131411121314l1121314,~"ARTER 1971 I 1972 I 1973 I 1974 I 1975 I 1976 1 1977 I 1978

Figure 1 Quarterly elemental concentration in air near ground level at Wraymires, Cumbria ( 197 1- 1978) (Reproduced by permission from AERE Harwell Report R9484)

Garmi~ch-Partenkirchen.~'~,'~~ Measurements from 1972-1977 have shown 217 that continental air masses contain 2-3-fold more Al, Ca, Fe, K, Si, N H f , SO:-, and TSP than do maritime air masses. Together, SO:-, NH:, and NO5 can comprise -77% of the continental aerosol and -59% of the maritime aerosol mass.217Background aerosols in the southern hemisphere are being sampled at 5250 m altitude, on Chacaltaya Mountain, Bolivia."* At Mauna Loa Observatory, Hawaii (3380 m above sea level), optical characteristics of vertically integrated background aerosol have been measured above the trade wind inversions, where Aitken nuclei counts are only a few hundred per cm3.221Incursions of aged continental tropospheric aerosol to Mauna Loa from N. America caused an increase of -0.007 in absorbance at 500 nrn above the natural background (-0.0 15) and from the enhancement in spectral extinction under the influence of continental aerosol, the point-mass loading of such particulates in a 5 km column above the Observatory is estimated at 1 pg m-3.221 Seasonal variations in concentrations of elements in air are reported in non-urban regions of the UK222and typical results at one station are shown in Figure 1. From

-

R. Reiter, R. Sladkovic, and K. Potzl, Meteorol. Rundsch., 1975, 28, 37. R. Reiter, R. Sladkovic, and K. Potzl, Ber. Bunsenges Phys. Chem., 1978, 82, 1188. * 1 8 F. Adams, R. Dams, L. Guzman, and J . W. Winchester, Atmos. Environ., 1977, 11, 57 1. 'I9 G. McInnes, Rep. LR 305 (AP). Warren Spring Lab., Stevenage, 1979. 220 N. J. Pattenden, AERE Harwell Report R 7729, H.M.S.O., London, 1974. 2 2 ' G. E. Shaw, J . Atmos. Sci., 1979, 36, 862. 222 P. A. Cawse, AERE Harwell Report R 9484, H.M.S.O., London, 1980. 'Ib

2'7

20

Environmental Chemistry

average results at four non-urban stations,222the highest increase in winter was observed for Br (2.6 fold), with 1.5-2-fold increase for As, C1, Cr, Co, Cu, Mn, Na, Ni, Pb, Sb, Se, V, and Zn. Little seasonal difference was noted for Al, Ce, Sc, and TSP. However, at the Jungfraujoch Observatory the opposite was found, with minimum elemental concentrations in the winter months,215which was attributed to snow cover and remoteness from industry: in April, levels of elements and TSP increased by an order of magnitude and fell again in October. In Northern Nigeria, under ‘dry season’ conditions of dust-laden Harmattan wind from the Sahara desert, concentrations in air of Al, Br, C1, Co, Fe, Na, Pb, Sc, V, and Zn at a rural site increased by an order of magnitude above levels in the rainy season, from April to September, when a maritime tropical air mass was dominant.223 Bromine is present in the troposphere in both particulate and gaseous phases, the latter usually at 5-20 times greater concentration, and it is known that gaseous Br may act as a catalyst for recombination of ozone in the strat0sphe1-e.~~~ Particulate Br levels in non-urban regions of the UK are usually between 10-100 ng mC3air,3 although a sudden increase from December 1972 to January 1973 was seen to coincide with intense volcanic activity in Iceland.z25 Marine Aerosols.-The importance of marine aerosols, radii <0.2 pm, in the formation of clean air aerosols has encouraged detailed study of their composition.226Thus the main constituent in pure Atlantic air was S (0.2 pg m-3) and the fact that Ca, C1, and K were at least an order of magnitude lower and Br was (0.002 pg indicated the absence of sea salt in this particle-size range.226 reported that the mid-latitude oceanic regions of both North and South hemispheres show atmospheric concentrations of 300-500 particles cmP3 mainly in the size range 20 nm < r < 1 pm. Prospero228found that mineral aerosol levels were highest in the Tropical North Atlantic (14 pg m-3), the Indian Ocean (4.8 pg m-3), and the Mediterranean (4.3 pg m-3) indicating the influence of arid regions. Levels were reduced to 0.35-0.7 pg mP3 in the central and northern North Atlantic, the South Atlantic and Pacific oceans. However, the sea-salt aerosol measured by high-volume air sampling was relatively constant, from 3.3-8.7 pg m-3

228

Increases in ratios of S 0 4 / N a in marine aerosols relative to bulk seawater are reported over waters off North Brittany229and in sub-Antarctic areas of the Indian Ocean.230 Oxidation of biogenic gaseous sulphur compounds, mainly dimethyl sulphide to SO, and then to SO:- is believed responsible.230 G r a v e n h ~ r s t ~ ~ l described both excess SO:- and NH: in submicrometre aerosols over the North F. Beavington and P. A. Cawse, Sci. Total Environ., 1978, 10, 239. S. C. Wofsy, M. B. McElroy, and Y . L. Yung, Geophys. R e s . Lett., 1975.2,215. 2 2 5 P. A. Cawse, A E R E Harwell Report R 7669. H.M.S.O.. London, 1974. 226 P. Winkler, Geophjs. Res. Lett., 1975. 2,45. *” A. W. Hogan, ‘Proc. 9th Int. Conf. Atmos. Aerosols. Condensation and Ice Nuclei’, Galway, Ireland, 1977. p. 152. 2 2 x J . M . Prospero, J . Geophys. Res.. 1979, 84. 725. 2 2 y B. Bonsang, B. C. Nguyen, A. Gaudry, and G. Lambert. in ref. 227. p. 154. B. Bonsang, B. C. Nguyen, A. Gaudry. and G. Lambert, ‘Proc. Comm. Atmos. Chern. Global Pollut., Trace Gases and Aerosols,’ 1979. G. Gravenhorst, Atmos. Environ., 1978, 12. 707.

223

224

”(’

’”

Inorganic Particulate Matter in the Atmosphere

21

Atlantic, probably formed by gas to particle conversion to form SO:- aerosols that absorb NHZ. Concentrations of SO:- and SO, reported in marine and background continental locations are reviewed by M e s z a 1 - 0 ~over : ~ ~the ~ oceans the excess SO$is about twice the amount contributed by sea-salt aerosol. At 40”N in the North Atlantic the SO, concentration is found to increase by an order of magnitude to 2 pg mP3, possibly caused by a reduction in photochemical conversion rate or by advection of industrial-derived SO,. 232 Apart from this exception, which lowers the ratio S 0 4 / S 0 2to 0.4, the ratio is between 1 and 10 over the oceans and is higher than over continents. Marine aerosols from the Gulf of Mexico contained an average of 3030 ng mP3of particulate and inorganic gaseous C1, with an equivalent amount as organic gaseous Cl.233The proportion of gaseous to particulate C1 varied in the range 0.5-100.233 Marine aerosols have been examined in coastal regions to estimate trace-element fluxes to continental areas 234 and to study interactions between sea-salt aerosols, soil and mineral particles, and anthropogenic aerosols.235Maritime-background aerosol sampled on the coastline of Washington state, for trajectories with at least 3 days of oceanic traverse, contained 25 ,ug Fe m-3 and 1.9 pg Pb m-3: eleven other elements were measured.236In Central Queensland, Australia, the sea-salt aerosol at cloud-base level only decreased by a factor of 5 up to 1100 km inland, at mean wind velocities of 5 m s - ~ . * ~Maritime-background ’ aerosols are sampled by the Japanese Meterological Institute at Bonin Is, 27*N, and at Marcus Is, 24ON, as part of a W.M.O. network of baseline air monitoring stations.238Anthropogenic influences are believed to contribute significantly to I, Sb, Se, and Zn in these aerosols.238 Further research on enrichment of elements in marine aerosols is discussed in Section 4. The Stratospheric Background.-The importance of variations in the stratospheric aerosol concentration on solar radiation received by the earth 239 has encouraged investigations using direct sampling techniques in addition to indirect optical methods, to establish the normal background composition and mass, and to record disturbances from volcanic explosions and stratospheric aircraft flights. Current knowledge of stratospheric aerosols (and gaseous species) has been reviewed in 1975240and by several working groups in 1979.241Cadle and have discussed the optical properties. Sulphate aerosols formed in the stratosphere by oxidation of SO, and precursors such as COS and CS,243at mid-latitudes (in the E. Meszaros, Atmos. Environ., 1978, 12,699. W. W. Berg and J. W. Winchester, J . Geophys. Res., 1977,82, 5945. 234T.B. Johansson, R. E. van Grieken, and J . W. Winchester, Florida State Univ. Tech. Rep. 7-75, Tallahassee, FL, 1975. 235 K. Isono and Y. Ishizaka, in ref. 227, p. 82. 236 J. D. Ludwick, T. D. Fox, and S. R. Garcia, Atmos. Enuiron., 1977, !I, 1083. 237 W. D. King and C. T. Maher, Tellus, 1976, 28, 11. 238 Japanese Meteorol. Inst. Tech. Rep. I, Tokyo, 1978, p. 6. 239 C . Junge, Promet. Met. Fortbild, 1975, 5,9. *‘O CIAP Monograph, ‘The Natural Stratosphere of 1974’, US Dept. Commerce, Springfield, VA, 1975. 241 R. D. Hudson and E. 1. Reed (ed.), NASA Ref. Publ., 1049, 1979. 242 R. D. Cadle and G. W. Grams, Rev. Geophys. Space Phys., 1975, 13, 475. 243 P. J. Crutzen, Geophys. Res. Lett., 1976, 3, 73. 232 233

Environmental Chemistry

22

absence of volcanic eruptions) are usually in the concentration range 0.3-1.5 ng gg' of air, and the highest concentrations in this range are found in a 'layer' at 18-20 krn.*,, Nitrate, Br, C1, Na, and Si are generally detected at lower concentrations than SO,.241Gas reactions of NO, with SO, or gas-particle reactions between NO, and H,SO, are believed responsible for formation of NOHSO, and NOHS207, tentatively identified in stratospheric aerosols.245Much information on the global composition of the stratosphere and troposphere between 6-1 3.5 km altitude is being gathered by the NASA aircraft sampling programme for 'GASP' (global measurements of atmospheric species), initiated to study the effects of aircraft exhaust emissions on the upper atmosphere.246Between 3 0 4 5 ON latitudes, SO:levels of 0.2-0.4 pg rn-, are reported in the upper troposphere, increasing to 0.5-1.4 pg rn-, in the lower ~tratosphere.~,~ Theoretical considerations of the formation and growth of H,SO, particles indicate that at normal stratospheric water-vapour concentrations of 1-2 p.p.m., growth of existing particles by vapour condensation is more important than formation of new particles by heteromolecular nucleation reactions for altitudes of 12-2 1 km.247 At altitudes of 18-20 km, general aerosol concentrations are 3 particles cm-, ( r 2 0.1 pm) decreasing to 2 at the North polar region.248 Eruption of the Fuego volcano in Guatemala in October 1974 caused a sudden increase in stratospheric aerosol loading above background, in a layer between 15 and 22 km altitude.249Volcanic eruptions can result in 1 to 2 orders of magnitude increase in stratospheric SO:-, returning to background 1 to 13 years after the event.250.251Although the SO:- and NH; inventory of the stratosphere was increased by the Fuego volcano, no increases in particulate C1 or HNO, vapour were seen and initial injection of S to the stratosphere in the gaseous phase is likely.251 In the Southern hemisphere at Mildura (34OS, 142OE), G r a ~ reported ,~ that SO:- was a major constituent of stratospheric particles from 0.03-1 pm radius, with an estimated mass of 1.1 x 10-lo kg H,SO, in a 1 cm2 column between the tropopause (12.9 km) and 30 km altitude. In 1977 a major incursion of NH, to 16-28 km was observed, causing a change from a predominant sulphuric acid aerosol to ammonium ~ulphate.,~

-

-

Urban Aerosols.-Absolute concentrations of elements in urban atmospheres of the UK are compared in Table 1 with levels at Collafirth, Shetland Is., a remote background station. In many comparative studies the observed concentrations are referred to a single element, selected to represent a natural source material such as soil or marine aerosol. Thus the choice of reference elements to indicate the

244

245

A. L. Lazrus and B. W . Gandrud, Geophvs. Res. Lett., 1977,4, 521. N . H. Farlow, K. G . Snetsinger, D. M. Hayes, H. Y. Lem, and B. M. Tooper,J. Geophys. Res., 1978,

83, 6207. D. J. Gauntner, J. D. Holdeman, D. Briehl, and F. M. Humenik, NASA Tech. Mem. TM-73781, 1977. 247 G. M. Hidy, J. L. Katz, and P. Mirabel, Atmos. Environ., 1978, 12, 887. 248 N. H. Farlow and G. V. Ferry, J . Geophys. Res., 1979. 84, 1 3 3 . 249 M. P. McCormick, T. J . Swissler, W . P. Chu, and W . H. Fuller, J . Atmos. Sci., 1978, 35, 1296. 250 A. W. Castleman, H1 R. Munkelwitz, and B. Manowitz, Tellus, 1974, 26, 222. 2 5 1 A. L. Lazrus, R. D. Cadle. B. W. Gandrud, and J. P. Greeberg.J. Geophys. Res.. 1979,84, 7869. 246

Inorganic Particulate Matter in the Atmosphere

23

contribution to the aerosol from soil or earths crust may be made from Al, Ce, Fe, Sc, Si, or Ti, while for sea salt, Na is the obvious definitive marker element. Enrichment factors for individual elements in the aerosol are then calculated from the following relationship, where Sc is selected as a reference element: = Enrichment factor for element X (Ex)

X/Sc in aerosol ~

X/Sc in source (using average soil or crustal concentrations) It follows that: [Element Xl soil Element X in the aerosol from resuspension = [Sc] atmosphere x [Scl soil An intercomparison of aerosol-crust-enrichment factors recorded at urban and rural locations throughout the world has been made by Rahn.252Enrichments of several orders of magnitude are frequent in industrial atmospheres and the mechanism of enrichment has been related to high volatility of chalcophilic elements, e.g. Cd, Pb, and Zn compared to lithophilic elements such as Al, Fe, and Sc.215,253 The volatile metals show preferential condensation on submicron airborne particles with relatively high surface area.215,253 Some element enrichments recorded in non-urban regions 254 are compared in Figure 2. At latitudes remote from heavy industry such as N. Nigeria, element enrichments in air particulate are significantly lower than at non-urban locations in the UK (Figure 2), where metals such as As, Pb, Se, and Zn are enriched by 2-3 orders of magnitude above soil reference values and are associated with small sub-micrometre particles typically produced by industrial combustion and condensation processes.255These high enrichments of metals at non-urban sites in the UK are very uniform, even though the absolute concentration may differ considerably, and similarity with more distant stations at comparable latitudes is also noted;255widespread industrial influences are implicated. Vertical profiles of aerosols over the Los Angeles basin have shown that concentrations of condensation nuclei (d < 0.1 pm) and secondary aerosols (d 0.1-1 pm) fall by an order of magnitude above the mixing layer at -900 m, with values at the surface usually in the range 50-100 x lo3 cm-3.256Measurements of vertical profiles 21 km downwind of an urban area detected decreases of -50% up to 900 m for Br, Ca, Fe, Mn, and Pb with further decreases in concentration approaching an order at magnitude of 900-1 200 m, but no profile differences were found for S, SO,, or Zn.257 However, measurements over Hungary showed increasing S 0 4 / S 0 , ratios from 0.6 at ground level to 6 at 3 km altitude, similar in

-

K. A. Rahn, The Chemical Composition of the Atmospheric Aerosol. Tech. Rep. Univ. Rhode Is.. Kingston, 1976. 253 R. Heindryckx, Atmos. Environ.. 1976. 10, 65. 254 D. H. Peirson and P. A. Cawse. Philos. Trans. R . SOC. London., Ser. B , 1979, 288.41. *H P. A. Cawse, AERE Harwell Report R 8869, H.M.S.O., London, 1977. 2 5 6 R. B . Husar and D. E Patterson, J . Appl. Meteorol., 1977, 16. 1089. 2s7 J . A. Young and A. J. Alkezweeny. Ann. Rep. Pacific Northwest Lab., Part 3 . Richland, WA., 1978, p. 1 and p. 42.

252

Environmental Chemistry

24

1ooc

-u

v)

0

c

x

in = 100 0

E0

a e C

*

* 2

.

10

I-

Z W

z I

0

a 1.0

Z W

0.1

I 1

3 4

L I

1 2 3 4

Fe

Mn

v

L

L

4

As

cu

Zn

Se

Pb

Figure 2 Air particulate enrichment factors at non-urban locations (1976). Site 1, Chilton, Oxon. UK; 2, Leiston, Suflolk UK; 3, Plynlimon, Powys UK; 4, Bagauda, N. Nigeria

* Enrichment Factor =

Air concentration of element Air concentration of Sc

I

Average soil concentration of element Average soil concentration of Sc

(Reproduced by permission from AERE Harwell Report R8869)

fact to ratios over maritime areas.258Layered aerosol patterns are reported up to 3 km over central European USSR from profile studies by optical methods under stable anticyclonic weather conditions.25 Further details of urban aerosols are discussed in subsequent paragraphs on monitoring networks and trends in aerosol concentrations.

25n

G. Varhelyi, Tellus, 1978, 30, 542.

259

Y. P. Dyabin, M. V. Tantashev, S. 0. Mirumyants, and V. D. Marusyak, Izv. A m o s . Ocean. Phys., 1977, 13, 831.

25

Inorganic Particulate Matter in the Atmosphere

Inorganic Particulate-Organic Interactions.-The adsorption of organic components on airborne inorganic particulate matter is important when estimating health hazards of dust and in the dispersion and transport of pollutants. Soot particles can contain several polycylic aromatic hydrocarbons 260 and N-containing aromatic compounds such as aza-arenes.26’ Mutagenic tests on polycyclic aromatic hydrocarbon compounds extracted from air particulate showed that benzo[ alpyrene quinones were direct acting mutagens.262During photochemical smog episodes in Pasadena when the TSP loading reached 300 pg m-3, the organic carbon fraction comprised about 43%.263 Adsorption of tetraethyl-lead vapour by silica and carbon black is reported from laboratory tests, leading to greatest enrichment of Pb in the smaller particle range.264In an urban atmosphere, 0.2-1.2% of total particulate Pb was accounted for by sorbed ~ r g a n o - P bFibres . ~ ~ ~ of chrysotile asbestos adsorbed up to 10 times more organic test compounds than the crocidolite form.266 Air particulates from various parts of Belgium contained 90% of the total mass of benzo[alpyrene on particles <2 pm diameter with residence times of 10-100 h, with potential for long-distance transport. Paraffinic compounds, mainly C 18--c35, associated with larger particles and were less liable to dispersion over long distances.267From research on photochemical decomposition of chloromethanes and N 2 0 adsorbed on sand particles, a surface-sensitized photolysis mechanism is indicated that can enhance destruction of these gases in the troposphere, to correspond with observed residence times.268 the range of particle diameter Particle-size Associations of Elements.-Within 0.005-100 pm, frequently observed bimodal distributions of aerosol mass are an expression of condensation- and combustion-derived aerosols that contribute to the small particle mode and mechanically-generated aerosols from resuspension of soil Some authors have reported trimodal dust, with diameters from 5-100 distributions for urban aerosols caused by the separation of fine submicrometre particles into an accumulation mode at d 0.1-0.5 p m from coagulation and condensation of primary particles, and a smaller or ‘nuclei’ mode ( d 0.02 pm) from direct combustion-derived particle^.^^^.^^^ The difficulty of representing particle-size concentration relationships in the atmosphere by the Junge-type (log-radius number) continuous distribution, which is inadequate for the diversity of sizes and sources often encountered, has been

-

-

260D. Hoffman and E. L. Wynder, Am. Chem. SOC.,Monogr., 1976, 173,324. S. Krishnan, D. A. Kaden, W. G. Thilly, and R. A. Hites, Environ. Sci. Technol., 1979, 13, 1532. 262 M. F. Salamone, J. A. Heddle, and M. Katz, Environ. Int., 1979, 2, 37. 263 D. Grosjean and S . K. Friedlander, J . A i r Pollut. Control Assoc., 1975, 25, 1038. 2 6 4 H .W. Edwards, R. J. Rosenvold, and H. G. Wheat, Trace Subst. Environ. Health, ed. D. D. Hemphill, Univ. Missouri Press, 1975, 9, 197. 265 R. M. Harrison and D. P. H. Laxen, Atmos. Environ., 1977, 11, 201. 266 J. P. Contour, I. Guerin and G. Mouvier, in ref. 41, p. 255. 26’ F. De Wiest, Atmos. Environ., 1978, 12, 1705. R.E. Rebbert and P. J. Auslous, W.M.O. Rep. 551, World Meteorol. Org., Geneva, 1978, p. 31. 269 D. A. Lundgren and H. J. Paulus,J. Air Pollut. ControlAssoc., 1975,25, 1227. 270 K . T. Whitby, Atmos. Environ., 1978, 12, 135. 271 D. N. Kelkar and P. V. Joshi,Atmos. Emiron., 1977, 11, 531. 261

Environmental Chemistry

26

discussed, with preferred interpretation from mass and volume d i s t r i b ~ t i o n s . ~ ~ ~ - ~ ~ ~ The detailed components of particle-size spectra, representing contributions from natural and pollution sources are outlined by S1in1-1~~~ using log area distributions 270 reviewed various forms of presentation of particle-size (um’ ~ m - ~ )Whitby . distributions with special reference to sulphur aerosols. The increase in particle size of SO:- aerosol with increasing humidity is close to theoretical curves for ammonium sulphate 277 and changes in relative humidity are important when interpreting particle-size data.278Above relative humidities of -0.9, water uptake of a mixture of salts typical of aerosols is almost equal to uptake by all individual Properties of particulate sulphur aerosols and associated metal and organic inclusions are reviewed with reference to their hygroscopic growth within the accumulation mode range of approximatley 0.1 < d < 1.0 pm, which includes most SO:- particles in the ambient atmosphere.280 Large particles with diameters between 5 and 55 p m occurred both upwind and downwind of St. Louis, Missouri at 300 m altitude, where active mixing in the boundary layer must have reduced the effectiveness of removal by sedimentation.281 Within the urban plume of St. Louis, particles in the size range 0.1-1 pm showed in 1.5 h by gas to particle conversion: the growth from 45 pm3 cmP3to 66 pm3 concentration of particles decreased with time, confirming a coagulation mechanism.282 Aerosols from industrial areas of Ghent and Toronto showed association of oxyphilic elements of low enrichment factor mainly with larger particles ( d > 1 pm), whereas chalcophilic elements of high enrichment were associated with submicrometre sizes.253,283 However, near a battery re-cycling plant in Toronto the As, Pb, and Sb were also found in larger particles (d > 3.3 pm), where the source of Pb was identified as automobile exhaust by good correlation with Br.283In Japan, an episode of loess aerosol incursion to the Osaka area affected ‘normal’ particle-size associations around 4 pm, with order of magnitude increases in concentrations of Al, Co, Cr, Fe, K, Th, and V.284For Br, C1, Sb, Se, and Zn the concentration was increased in the smaller particles (d 1 pm) suggesting attachment of urban aerosols to soil particles. Aerosols sampled by cascade impactor over the Arabian sea along 20° N latitude contained a large amount of continental-derived material, judged by the presence of Cr, Fe, Mn, and S C . ’ ~ ~ MeszarosZE6examined seasonal differences in airborne particles from residential Budapest: summer increases in the surface distribution of soluble relative to

-

C. N. Davies, Aerosol Sci., 1974, 5. 293. K. Willeke and K. T. Whitby, J . Air Pollut. Control Assoc., 1975, 25, 529. 274 R. Jaenicke and C. N. Davies, J . Aerosol Sci., 1976, 7 , 255. 27s H. A. Bridgman, Atmos. Enuiron., 1979, 13, 629. 17’ W. G. N. Slinn, Atmos. Environ., 1975, 9, 763. 277 M. S. Ahlberg and J. W. Winchester, Atmos. Environ., 1978, 12, 163 1. 278 G. Hanel, Adv. Geophvs., 1976, 19, 73. 279 G. Hanel and B. Zankl, Tellus, 1979, 31,478. ”” R. J. Charlson, D. S. Covert, T. V. Larson, and A. P. Waggoner, Atmos. Enuiron., 1978, 12, 39. 28’ D. B. Johnson, Science, 1976, 194, 942. 2R2 A. J. Alkezweeny, J . Appl. Meteorol., 1978, 17, 609. 2n3 J . J . Paciga and R. E. Jervis, Environ. Sci. Technol., 1976, 10, 1124. ZR4 A. Mizohata, T. Matsunami, and T. Mamuro, Annu. Rep. Radiar. Cent. Osaka. 1976. 17, 1. 283 S. Sadasivan, Atmos. Environ.. 1978, 12. 1677. 286 A. Meszaros. Atmos. Eni?iron.,1977. 11. 1075.

272

271

Inorganic Particulate Matter in the Atmosphere

27

insoluble particles were attributed to photo-oxidation of SO,, but in winter the latter were predominant in the same size mode (d 0.07 pm). In the Nagoya industrial area of Japan, nitrate aerosols showed a bimodal size distribution, with NH,NO, Absolute predominant at d = 0.4-0.6 pm and NaNO, at d = 3-5 concentrations ranged from 1.2-5.7 pg m-3, but whereas in autumn and winter the NO, was mainly associated with submicrometre particles the reverse was true in Diurnal variations for summer under conditions of southerly maritime NO, aerosols were reported in the California South Coast Air Basin, with larger particles of diameter 0.3- 1.6 p m found mainly in early morning when humidity was high.288Increases in particle concentrations in early morning with a minimum in the afternoon were observed in Tel AvivZS9and in the rural N. pen nine^.^^^ Size distributions and electron micrographs of stratospheric aerosols from 0.09-1.4 p m in diameter were reported by Bigg,291who noted a marked seasonal variation in the lower stratosphere at a height of 10-16 km.

-

Photochemical and Gas-phase Reactions.-Research on transformations of gaseous species to particulate forms by gas-phase interactions and by reactions between liquid droplets and particulates has ~ o n t i n u e d . ~Co ~ x~ -has ~ ~reviewed ~ studies on the photoinitiated gas-phase oxidation of SO, and in W. Europe oxidation rates up to 4% h-’ are predicted for a hydrocarbon-nitrogen oxide polluted atmosphere under ambient summer conditions. It is considered that oxidation by free radicals such as OH, HO,, and their organic analogues plays a major role.295 In power station emissions, oxidation rates for SO, to particulate SO:- of 1-3% h-’ were found in summer, but much less (<0.5%) in winter, mainly from homogeneous gas-phase reactions.296 These reactions may form submicrometre particles of H,SO,, NH,HSO,, and (NH,),SO, as indicated by infrared spectra.297 Cosmic-ray-produced 38Sis suggested as a possible tracer to study SO, oxidation rates.298 Differences in rates of removal of SO, by heterogeneous reactions with particulate materials such as fly ash and mineral oxides to form particulate SO:- are reported.299In the aqueous phase, oxidation of 35S0,tracer dissolved in rainwater was catalysed very effectively by Mn and to a lesser extent V, but showed little resonse to Fe.300

287

S. Kadowaki, Afmos. Environ., 1977, 11, 67 I . B. R. Appel, E. L. Kothny, E. M . Hoffer, G. M. Hidy, and J. J. Wesolowski, Emiron. Sci. Techtiol., 1978, 12,418.

’” Z. Levin and J. D. Lindberg,J. Geophvs. Res., 1979.84.6941. S. G. Jennings and R. K. Ellison, Afmos.Environ., 1977, 11, 36 1. E. K . Bigg, J . Atmos. Sci., 1976, 33, 1080. 292 S. P. Sander and J. H. Seinfeld, Environ. Sci. Technof., 1976, 10, 1 1 14. 293 T. V. Larson and H. Harrison, Atmos. Environ., 1977, 11, 1133. 294 A. J. Alkezweeny and D. C. Powell, Atmos. Environ.. 1977, 11, 179. 295 R. A. Cox, Philos. Trans. R . SOC.London, Ser. A , 1979, 290, 543. 296 M. A Lusis, K. G. Anlauf, L. A. Barrie, and H. A. Wiebe. Atmos. Environ., 1978, 12, 2429. 2y’ P. T. Cunningham and S. A. Johnson, Science, 1976, 191, 71. 298 W. Roedel, W. Junkermann, and L. Leidner, Nature (London), 1977,268,320. 299 H. S. Judeikis, T. B. Stewart, and A. G . Wren, Atmos. Environ., 1978, 12, 1633. 300 S. A. Penkett, B. M. R. Jones, and A. E. J. Eggleton,Atmos. Environ.. 1979, 13. 139. 30’ D. Grosjean (ed.), ‘Nitrogenous Air Pollutants - Chemical and Biological Implications‘, Ann Arbor. MI. 1979. 290

291

28

Environmental Chemistry

Formation of nitrate aerosols by chemical reactions in polluted atmospheres 301 has received less attention than sulphates, although tests in reaction chambers have provided evidence on the significance of gas-phase and aqueous-phase r e a ~ t i o n s ,which ~ ~ ~ is , ~discussed ~~ by Orel and S e i r ~ f e l dIn . ~ laboratory ~~ tests, loss of NO: from aerosol particles was detected, probably as HNO,, during photo-oxidation of SO, to H,S04, but the NH6 content remained unaffected.303The presence of particulates containing oxides of Cu, Mo, and Zn increased the initial formation rate of HNO, from NO,, accompanied by morphological changes in the aerosol.305In Tokyo, the daily maximum particulate NO; concentrations in air ,ug m-3.306The urban aerosol in St. Louis, Missouri, were mainly from 0.4-1 contained 4.7% of the total particulate load as N H t and 0.62% as NO?, with NO, not detectable: altogether, these three species accounted for 83% of total N in the The volatile and particulate fractions of certain metals have also been investigated; at Long Island Sound, Connecticut, volatile Hg (fraction passing a 0.4 pm glass fibre filter) was present at 7.5-9.5 ng mP3compared to 0.29 ng m-3 in the particulate form.30s A ratio of 22 f 12 was found for particulate/vapour phase As in the New York atmosphere, at mean particulate As concentrations of 3.6 ng mP3, while near a copper smelter this ratio increased to -70 at levels of 2000 ng rnd3 of particulate As.309 Atmospheric Monitoring and Surveillance Networks.-The objectives of national or regional networks may be 'surveillance', defined as the procedure for assessing concentrations of atmospheric contaminants to meet air quality needs, or 'monitoring' to assess short- or long-term changes in air quality for control, basic research, or epidemiological purposes. Suess 310 has reviewed the principles and objectives of the World Health Organisation global environmental monitoring system (GEMS), initiated within the United Nations Environmental Programme (UNEP) to develop a global and regional strategy in collaboration with the W.M.O. Over 60 countries and 200 monitoring stations are now co-operating to provide data on urban311 and rural concentrations of TSP and gaseous pollutants: it is also intended to include Pb. The baseline and regional air-pollution monitoring stations operated by the W.M.O. in 20 countries provide data on atmospheric turbidity and precipitation chemistry of major ions.312No significant changes in land use must be expected for at least 50 years within 100 km of a baseline W.M.O. station. Guidelines for basic W. E. Clark, D. A. Landis, and A. B. Harker, A m o s . Environ., 1976, 10, 637. A. B. Harker, L. W. Richards, and W. E. Clark,Atmos. Environ., 1977, 11, 87. jo4A. E. Orel and J. H. Seinfeld, Environ. Sci. Technol., 1977, 11, 1000. ' 0 5 H. M . ten Brink, J. A. Bontje, H. S. Poelstra, and J. F. van de Vate, in ref. 41, p. 239. '06 T. Okita, S. Morimoto, and M. Izawa, Atmos. Environ., 1976, 10, 1085. '07 C. W. Spicer, Atmos. Environ., 1977, 11, 1089. W. F. Fitzgerald and G. A. Gill, Anal. Chem.. 1979, 51, 17 14. ' 0 9 P. R Walsh, R. A. Duce, and J. L. Fasching, J . Geophys. Res., 1979,84, 1710. 'lo M. J . Suess, Atmos. Environ., 1979, 13, 21 1. W.H.O. Offset Publ. 30, 'Air Quality in Selected Urban Areas', World Health Organisation, Geneva, 1976. ' I 2 'Global Monitoring of the Environment for Selected Atmospheric Constituents', Rep. Natl. Ocean. Atmos. Admin., Environ. Data Services, Washington DC, 1977. '02

jo3

'""

Inorganic Particulate Matter in the Atmosphere

29

air-monitoring projects in urban areas to observe long-term trends in air quality are available.313Project ‘OPAQUE’ was started by NATO in 1976 to examine changes in optical atmospheric quantities in Europe in relation to geography and weather, and includes particle-size distribution and refractive-index data, in addition to optical measurements from ground level to 5000 m.314An Arctic air-sampling network of some 13 stations is being established,315and preliminary measurements have shown that V and SO:- increase by 10-50 times in winter when the polar front moves southward and encompasses industrialized regions within the polar air mass.316 Hence, non-maritime SOP at Barrow, Alaska, can reach 2 pg m-3 in

-

inter.^ l 6 A network of rural stations throughout South America has indicated sulphur concentrations of -150 ng m-3 in interior Brazil compared with 10 ng m-3 in South Chile;317 heavy metals are also inve~tigated.~ Trace and major elements in air particulates from non-urban locations in the UK have been measured since 1972.222 The US Environmental Measurements Laboratory has continued to record concentrations of metals in air at 42 non-urban and urban stations from latitudes 71°N to 90°S.318 Monitoring networks for trace elements in air particulates have frequently been designed to compare both urban and rural sites within a region. A survey of heavy metals over 5 years at 15 such stations in Belgium showed highest inter-site variability for Cu and Zn followed by Ba, Cd, Fe, and Mn, reflecting the influences of point sources of emission, but Cr, Ni, Pb, and V were less variable and typical of more diffuse origin.319 Measurements in the Ostend area indicated extensive pollution by continental air relative to maritime airflows from northerly quarters.320 At severely polluted sites in a network of stations throughout N. Bohemia the dust As up to 0.5 pg m-3 and Zn to 0.98 pg m-3.321In levels reached 850 ,ug M - ~ with , France, warning networks are established in industrial and agricultural areas, while observation networks are operated to record potentially hazardous emissions from specific sources; in Paris, particulate Pb is measured at 11 In South Africa, 23 trace elements are analysed in air filters from 2 1 urban and rural stations.323 Multielement studies of air pollution reported in specific industrial zones and cities of the world include Milan and Paderno Dugnano, Italy,324Hobart, Tasmania,325Trombay, India,326Birmingham and the Black Country, UK,327and W.H.O. Offset Publ. 33, ‘Air Monitoring Programme Design for Urban and Industrial Areas’, World Health Organisation, Geneva, 1977. 3’4 T. S. Cress and R. W. Fenn, Proc. SOC.Photo. Opt. Instrum. Eng., 1978, 142,45. 3 1 5 K. A. Rahn, Arctic Bull., 1978, 2, 343. 3L6K. A. Rahn and R. J. McCaffrey, ‘Proc. Conf. Aerosols: Anthropogenic and Natural Sources and Transport’, New York Acad. Sci., New York, 1979. j L 7 D. R. Lawson and J. W. Winchester, Geophys. Res. Lett., 1978,5, 195. 3 1 8 US Environ. Meas. Lab. Rep. EML-344, Dept. of Energy, New York, 1978. ’I9 J. G. Kretzschmar, I. Delespaul, and T. de Rijck, Sci. Total Environ., 1980, 14, 85. 320 J. G. Kretzschmar and G. Cosemans, Atmos. Environ., 1979, 13, 267. 3 2 1 J. Santroch and I. Obrusnik, Ochrana Ovzdusi, 1975, 7 , 129. 3 2 2 J. Vareille, in ref. 41, p. 21. 323 C. M. Vlegaar, J. L. Watkins, B. Wells, and A. Briggs, Health Phys.. 1979, 36, 555 J24 L. Alessio, G. Cambiaghi, E. Croce, P. Frigieri, and R. Trucco, Med. Lavoro, 1979. 1, 24. jZ5 H. S. Goodman, B. N. Noller, G. I. Pearman, and H. Bloom, Clean Air, 1976, 10, 38. 326 R. Sequeira and D. N. Kelkar, Indian J . Meteorol. Hydrol. Geophys., 1975, 26, 113. 327 A. C. Turner and C. M. Killick, Rep. LR 303 & 304, Warren Spring Lab., Stevenage, 1979.

Environmental Chemistry

30

other cities of the UK.328These investigations involve continuous measurements for at least 6 months and often several years. However, short-term examination of 2-24 h fluctuations in concentrations of elements in relation to meteorological factors has been used to identify related aerosol constituents and their local s o u ~ c e s329 .~~~~ In Japan, TSP measurements at 177 monitoring stations in 79 cities showed that 24% attained the standard of 100 ,ug m-3 as a long-term daily average.330TSP data from 29 urban sites in Canada have been summarized.331 Only half the monitoring stations in Belgium met the EPA primary air-quality standard of 75 ,ug m-3 332 Daily measurements of smoke concentrations in the UK are provided by a National Survey,333and results from 1960 are summarized in pollution statistics.334 Earlier data from country sites showed that annual average levels of 10 ,ug smoke m-3 increased by -4-fold in winter, caused by dispersion from industrial regions such as Walsall, where smoke levels reached 230 ,ug mP3in calm weather.335Large variability between stations of smokeshade and SO, data was reported in New York City,336and E l ~ o m ~applied ~ ’ spatial correlation analysis to similar data from the UK: he established better correlations for smoke than for SO,, possibly owing to larger differences in emission heights of the gas that affects dispersion patterns. Precipitation chemistry stations have been established in Europe (EACN-IMI network) and the USA.338Additional networks have been operated in Sweden339 and S. Florida.340In St. Louis the sampling of precipitation and aerosols is being made to examine effects of urbanization, under project ‘ M e t r o m e ~ ’Trace . ~ ~ ~ and major element analysis is reported from an on-going network of rain and air stations in Holland.342Dust deposit gauges at sites in the Meuse industrial basin indicated deposition of 180 mg m-2 day-’ in rural areas, increasing to 3000 mg m-* day-’ near to steelworks:343zones of heavy deposition were found for Cd, Cr, F, Hg, Pb, and Zn, and more intensive sampling is in progress. Near Liege, deposition of Cd is 650 times the background level of 0.0004 mg m-* day-1.343

-

Trends in Air Particulate Concentrations.-Trends in total suspended particulates and changes in concentrations of elements in the atmosphere are reported from long-term measurements in urban and non-urban regions. Trends in TSP in N.E. USA are being examined as part of the ‘Multi-State Atmospheric Power Production

’**M. Demuynck, K. A. Rahn, M. Janssens, and R. Dams, Afmos. Environ., 1976, 10, 21. J. 0. Pilotte, J. W. Winchester, and J. W. Nelson, J . Appl. Meteorol., 1978, 17, 627. Japan Environ. Summary, Environment Agency, Tokyo, 1979. 7, p. 1. 3 3 1 P. Ricci, H. Inhaber, and M. Pinchuk, Atmos. Environ., 1978, 12, 2369. 3 3 2 M. Demuynck and R. Dams, Atmos. Environ., 1975, 9, 1033. Anon., ‘The lnvestigation of Air Pollution; National Survey of Smoke and SO,. Apr. 1977-March 1978’, Warren Spring Lab., Stevenage, 1979. 334 Dept. of Environment, ‘Digest of Environmental Pollution Statistics 2’, H.M.S.O., London, 1979. R. A. Barnes, ‘Science, Technology and Environmental Management’, R. D. Hey and T. D. Davies (ed.), Lexington Books. Lexington, New York, 1975, p. 165. I. F. Goldstein and L. Landovitz, Atmos. Enuiron., 1977, 11,47. 337 D. M. Elsom, Atmos. Environ., 1978, 12, 1103. 3 3 8 J. M. Miller, in ref. 573, p. 639. 3 3 9 L. Granat, in ref. 573, p. 53 I . 340 J. Wisniewski and W. R. Cotton, in ref. 573, p. 61 I D. F. Gratz in ref. 573. p. 7 1. 342 Provinciale Waterstaat van Noord-Holland. Half-yearly Rep. Summer 1979, Haarlem, 1980. 343 W. Duhameau and R. Noel, in ref. 41, p. 29. 32y 330

’”

”’

j4’

31

Inorganic Particulate Matter in the A tmosphere

Table 2 Trends in element concentrations in air at rural locations in England ( 1970- 19 78)222 Slope*, percent yr-’ at:

Element Chilton, Oxon. A1

As Cr Fe Pb

Zn Na and CI

1972-1978

Styrrup, Notts. 1972- 1978

-8.4 -14 -15 -6.0 -8.5 -19

-1 1 -17 -17 - 14 -16 -19

ns

ns

Wraymires, Cumbria 19 70- 19 7 8 -7.2 -3.3 -12

ns -12 -18

ns

*Slope i s expressed as percent yr-’ of the mean annual air concentration from 1972-1978, or 1970-78 at Wraymires. ns indicates no significant trend.

Pollution Study’ (MAP3S),344while some earlier data in the US showed a downward trend of -20% for urban stations but little change in non-urban areas with -30 pg TSP m-3.4 In the US National Energy Plan it is predicted that by 1985 the annual emissions of TSP will have decreased by -10% but SO, will increase by -19%.345 An apparent decrease in TSP since 1960 at Newark, N.J. is correlated with a decrease in humidity, probably from local changes in land use.346In Canadian cities, visibility improved from 1953- 1963 and showed less marked changes in following years, but the reverse was noted in rural areas.347Trends in particulate air pollution near Tel Aviv were deduced from decreases in atmospheric electrical conductivity measurements that also agreed with deteriorating visibility, both consistent with increases over 9 years in submicrometre particles.34s It is now possible to examine trends in concentrations of particulate elements in air at non-urban sites in the UK over 8 years222 (Table 2) and earlier data (1957-1974) from Chilton, Oxon, is reported elsewhere.349A general impression is obtained of decreasing trends for many elements that are in broad agreement with decreases in black smoke and in Pb emissions from motor vehicles.334Downward trends for As, Cr, Pb, and Zn are not paralleled by maritime-derived elements such as Na and C1, and are greater than shown by elements that are associated with soil dust, such as Al, Fe, and Sc (Table 2).222A reduction in lead additive in petrol in W. Germany from 0.6 to 0.15 g Pb I-’ between 1971-1976 resulted in falls of 50% in airborne Pb in cities, but less in industrial regions with non-automobile sources of pollution.350 In Los Angeles County, atmospheric Pb fell by 50% between 1971-1976 and it is predicted that by 1982 the Pb concentrations should be 25% of 1976 levels (generally 2-4 ,ug m-3).351 Estimates of US automobile-Pb R. M. Brown and S. Sethuraman, in ref. 30, p. 3 18. Anon., Environ. Sci. Technol., 1978, 12, 376. 346 N. M. Reiss and J . J. Mangano, in ref. 30, p. 836. 34’ H. Inhaber, Nature (London), 1976, 253, 129. 348 A. Manes, in ref. 19, p. 109. 3 4 9 L. Salmon, D. H. F. Atkins, E. M. R. Fisher, and D. V. Law, J . Radioanal. Chew., 1977, 37, 867. 350 D. Jost and R. Sartorius, Atmos. Emiron., 1979, 13, 1463. M. C. Hoggan, A. Davidson, M. F. Brunelle, J. S. Nevitt, and J. D. Gins. J . Air Pollut. Control Assoc., 1978, 28, 1200.

344 ’45

32

Environmental Chemistry

emissions have been made to the year 2000 assuming phased reductions of Pb in fuel, economy standards, and emissions control Downward trends in the total (wet + dry) deposition to the ground at rural sites from 1971-1978 are reported for As, Co, Cr, Fe, Pb, and Sc at Chilton (Oxfordshire) and for Co, Fe, Sb, Sc, and Zn at Wraymires (Cumbria), in the absence of trends in In Denmark, falling trends were noted for deposition of Cd, Pb, and Zn, of -30% yr-’ from 1973-1975.353 Accumulation of metals deposited from the atmosphere was evident by increases of 23-7696 in concentrations of Cr, Cu, Fe, Ni, Pb, V, and Zn in epiphytic bryophytes from rural Denmark, collected between 1951-1975.’55 Temporal changes in heavy-metal deposition from the atmosphere have been studied by analysis of snow cores and fossil ice. In Poland, concentrations of Pb in ice increased 30 times between 1870 and the 1 9 6 0 ’ ~while , ~ ~ snow ~ cores from Mt. Blanc massif (Central Europe) covering the period 1948-1 974 showed -2-3-fold increases in Cd, Pb, and V concentrations since 1950 and a large excess of C1 from non-maritime sources, indicating anthropogenic inputs from the atmosphere.355 Other workers have found that enrichment factors (normalized to A1 in crustal rock) for Cd and Zn in Arctic snow are lower than in air parti~ulate,~’~ and therefore advise caution when using analysis of snow to interpret trends in element concentrations in the atmosphere; a sampling artifact or aerosol/snow fractionation may be responsible for this observation. 4 Characteristics of Emissions from Specific Sources

Resuspension of Soil.-Soils in the USA have been classified into seven wind-erosion groups,357the least erodible being group 7, the silts and non-calcareous silty clay loams. A soil with moderate wind-erodibility grouping (4), having 15-35% of dry soil aggregates >0.84 mm, has an erodibility index of 193 tonnes ha-’ yr-l, occurring by saltation and suspension by The annual flux of particulates from wind erosion over the Great Plains alone is estimated at 77 x lo6 tons yr-1,358 which may be compared with 35 x lo6 tons yr-l from other primary and anthropogenic sources in the US. Aerosols produced from dust storms in the US showed bimodal particle-size distributions with maximum diameters between 1-30 pm and 40-80 pm measured near to the ground, and differences in oxygen isotopic ratios were found in coarse and fine quartz, that are related to eroding soil sources.359 G. Provenanzo, J . Air Pollut. ControlAssoc., 1978, 28, 1193. M. F. Hovmand, ‘Atmospheric Metal Deposition in Denmark, 1975-6’, Rep. Tech. Univ. Lyngby, Denmark, 1977. 354 Z. Zaworowski, J. Bilkiewicz, M. Bysiek, D. Grzybowskya, L. Kownacka, and S. Wlodek, ‘Biological Implications of Metals in the Environment’, USERDA Symp. Series 42, NTIS, Springfield, VA, 1977, p. 628. 355 M. Briat, in ref. 41, p. 225. 356 K. A. Rahn and R. J. McCaffrey, Nature (London), 1979,280, 479. 35’ L. Lyles, Trans. ASAE., 1977, 20, 280. 358 L. J. Hagen and N. P. Woodruff, J . Air Pollut. Control Assoc., 1975, 25, 860. 359 D. A. Gillette, R. N. Clayton, T. K . Mayeda, M. L. Jackson, and K. Sridhar, J . Appl. Meteorol., 1978, 17, 832. 352

353

Inorganic Particulate Matter in the Atmosphere

33

In windblown dust from a sandy soil in the High Plains area of W. Texas, clay-coated quartz grains were predominant in the radius range 10-100 pm with illite and mixed-layer clays mainly in the range 1-10 pm.360The sandblasting effect from wind erosion appears to remove clay platelets from the surfaces of quartz grains.360In a semi-arid zone in S. Israel, the influence of soil dusts from the Dead Sea area was identified by concentrations of Co, Cr, Fe, Sc, Th, and Na, while urban aerosol incursions were associated with increases in Br and Hg.361The characteristics of resuspended soil dust from the Sahara desert are described by several authors.362In the Sahara Trade-Wind aerosol over the Atlantic the major components are 79% mineral dust, 16% sea salt, 3% (NH,),SO,, and 2% total organics; the majority of elements have enrichment factors close to unity indicating crustal origin.362 Bain and Tait 363 identified the mineral palygorskite in dust deposited on the Isle of Skye, Scotland, and suggested that it is a useful indicator of transport of soil dusts from N. Africa. In fact, the Arctic haze reported on many occasions over Alaska was shown to originate from resuspension of desert soils of E. With the onset of haze the enrichment factor of V was reduced to unity, indicating a crustal rather than pollution Crust-air fractionation of certain elements may occur during resuspension of specific particle-size fractions of soil Under dust storm conditions an enrichment of 20-fold for organic carbon was found at 3.5 m above ground for To identify major source areas of soil dust, particulates of diameter 5- 150 research is required to relate aerosol composition to that of the parent soil. Wind-tunnel experiments have provided valuable data on the effects of sandblasting, wind speed, soil consolidation, and surface texture on soil erosion.367Garland 36R measured significant resuspension from bare soil and grass of tungstic oxide particles labelled with lg5Wand of silt labelled with 114mIn, in controlled wind-speed experiments. Health hazards associated with contamination of surface soil by toxic materials have prompted the development of models to predict redistribution of soil dust at various wind speeds and to estimate air c ~ n c e n t r a t i o n s . ~ ~ ~ * ~ ~ ~ Resuspension of Marine Aerosol.-Further consideration has been given to the ocean as a major natural source of atmospheric particulates, as well as a 'sink' for material deposited from the atmosphere (see Section 6). It is estimated that 10'5-1016 g yr-1 of sea-salt particles with radii <20 p m are emitted, or between 30-75% of the total global production of particulates from natural sources.371 Probably 10% of these emitted salts are subsequently deposited to land, the remainder to the ocean. However, the elemental composition of the resuspended D. A. Gillette and T. R. Walker, Soil Sci., 1977, 123, 97. G. Shani and D . Cohen. Tellus, 1977, 29, 535. 362 'Saharan Dust, Scope 14', ed. C. Morales, Wiley, New York, 1979. 363 D. C. Bain and J . M. Tait, Clay Minerals, 1977, 12, 353. 364 K. A. Rahn, R. D. Borys, and G. E. Shaw, Nature (London), 1977,268,713. 365 K. A. Rahn, Atmos. Environ., 1976, 10, 591. 366 A. C. Delany and S. Zenchelsky, Soil Sci., 1976, 121, 146. 367 D. A. Gillette,Atrnos. Environ., 1978, 12, 1735. 368 J . A. Garland, AERE Harwell Rep. R9452, H.M.S.O., London, 1979. 369 J . R. Travis, Rep. LA-6035-MS, UC 11, USERDA. NTIS, Springfield, VA, 1975. T. W. Horst, Atmos. Environ., 1978, 12, 797. 37' R. A. Duce and E. J . Hoffman, Annu. Rev. Earth Planet. Sci.. 1976.4, 187.

360

361

34

Environmental Chemistry

marine aerosol is greatly influenced by materials deposited in the ocean, by the existence of a sea surface microlayer with different elemental composition to bulk seawater and by the spray-generation Thus enrichments of Cu, Fe, and Zn in the microlayer are reported373and Cu enrichments of 2 x lo4 relative to bulk seawater are found in marine aerosols near Tasmania, decreasing exponentially with altitude above sea Chemical fractionation of I gives enrichments of 100---1000 in marine aerosols.371 Alteration of Cl/Na ratios in precipitation samples collected at coastal sites in the EACN network have been questioned as an analytical artefact, and need not demonstrate fractionation in the sea-salt aerosol or alternative non-maritime sources of C1 or Na.375 Volcanic Emissions.--Volcanoes may inject particulate and gaseous material into the lower stratosphere and upper troposphere, and a large part of these emissions may be transported on a global scale to influence the chemistry of the background aerosol. Emission rates varying from 4-150 Tg yr-’ are estimated for total global particulate inputs from volcanic activity to the a t m ~ s p h e r e . Increases ~ in stratospheric aerosols were detected in 1975 following the eruption of the Fuego volcano in Guatemala in October 1974.376-37*In 1975 the emissions from Mt. Baker (N. Cascade Mts., Washington) suddenly The eruptions from Mt. Augustine in S. Alaska at the end of January 1976 did not penetrate to the stratosphere;380 analysis of particulates and gases from the plume showed that the volatile elements As, Br, C1, Sb, and Se were released early in the eruption.381 The enrichments of volatile elements in particulate emissions from volcanoes follow a similar sequence to the enrichments measured in aerosols from remote areas ~ ~the ~ * contribution ~ of such as the N. Atlantic Ocean and the A n t a r c t i ~ ~ *and volcanic activity to the chemistry of the background aerosol appears to be significant. Trace elements in particulate emissions ( d < 10 pm) from Mt. Etna in 1976 have been compared with estimates of anthropogenic emissions to the atmosphere from countries bordering the Mediterranean Sea:384 the volcanic discharge of Pb appeared insignificant, but was comparable to human emissions for Cd, Cu, Hg, and Zn, and was predominant for Se. These particulates from Mt. Etna possessed enrichment factors (normalized to Al) of 2100 for Cu, Pb, Zn, Sb, As, Ag, Cd, Au,

”*

P. S. Liss, ‘Chemical Oceanography’, 2nd Edn., ed. J . P. Riley and G . Skirrow. Academic Press, London. 1975. Vol. 2, p. 193. 3 7 3 R. A. Duce, G. L. Hoffman, B. J. Ray, I . S. Fletcher, G. T. Wallace, J. L. Fasching, S. R. Piotrowicz, P. R. Walsh, E. J. Hoffman, J. M. Miller. and J. L. Heffter, ‘Marine Pollutant Transfer’, ed. H. L. Windom and R. A. Duce. Heath and Co.. Lexington, MA., 1976, p. 77. 374 F. C . R. Cattell and W. D. Scott. Science, 1978, 202, 429. ’15 M. P. Paterson and R. S. Scorer, Nature (London), 1975, 254,491. 3 7 h F. E. Volz, Science, 1975, 189, 48. 171 R. W. Fegley and H. T. Ellis, Geophys. Res. Left.. 1975, 2, 139. 3 7 n D. J. Hofmann and J. M. Rosen, EOS Trans. A m . Geophys. Union, 1975, 56, 995. j7’ L. F. Radke, P. V. Hobbs. and J. L. Stith, Geophm. Res. Lett., 1976, 3,93. A. B. Meinel, M. P. Meinel, and G. E. Shaw, Science, 1976, 193, 420. ”’ W. H. Zoller, E. A. Lepel, E. J. Mroz, and K . M. Stefansson, in ref. 9, p. 157. E. J. Mroz and W . H. Zoller. Science, 1975, 190, 461. 383 E. A. Lepel. K . M. Stefansson, and W. H. Zoller, J. Geophvs. Res. 1978, 83, 62 13. 1R4 P. Buat-Menard and M. Arnold. Geophys. Res. Lett., 1978, 5, 245.

35

Inorganic Particulate Matter in the Atmosphere

Hg, and Se (in increasing In 1975, Mt. Etna released SO, at a mean rate of 3740 tonnes day-’, which is available for oxidation to form SO:- aerosols,385and any fraction of metals that are still in a gaseous state may later form condensation aerosols and could increase the reported significance of volcanic sources. A historical record of volcanic events may be retrieved by measuring the accumulation rate of volcanic glass (<6 1 pm) in deep-sea sediments.386 Sampling by aircraft of plumes from five Alaskan volcanoes and from Mt. Baker has indicated that a large fraction of the small particles and gaseous S can be emitted during less violent eruptive periods, therefore further attention should be given to such emissions as a source of particulates in the troposphere.387From St. Augustine an estimated 6 Tg was emitted over 1 yr, of which only 0.25 Tg was attributed to particles ( 5 p m diameter.387 Halo-type patterns given by some particles under the electron microscope are probably associated with acid sulphates, pm.387 and large amounts of Fe were present on particles with d = 0.3-1 Differences in concentrations of Al, Ca, Fe, S, and Si in particles with d = 4-1 1 p m are believed to result either from chemical differentiation in the lava or from interactions between the molten lava and the wall of the volcano.3ss Forest Fires.-A special feature of forest fires is that they produce large numbers of cloud condensation nuclei that may be transported for long distances, although the total mass of aerosol involved may be small relative to other sources of particulate emissions. Aerosols sampled in W. Africa during the dry season contained significant amounts of Ca, Mg, Na, and K, mainly from transport of particulates from fires in the Guinea savanna, and the Sudan savanna and forest regions: for K.389 In Georgia example, particulates <0.6 p m in diameter contained 2-3% (USA) -1 million acres of agricultural and forestry land are deliberately fired each year, emitting 29 000 tons of particulates to the atmosphere, but meteorological conditions favour rapid dispersal when burning occurs, mainly from January to March.390 Forest fires in W. Australia produce -lo5 tonnes of smoke yr-I by burning aboilt 200000 ha as forest management practice, with the main environmental nuisance being reduction in visibility.391Aircraft sampling in a forest fire plume that attained 1800 m and dispersed to 12 km width indicated an emission factor (particle mass produced per unit mass of material burned) of 4%;392 in 1 day of burning, an estimated 4.6 x lo6 kg fuel was ignited and about 80% of the particulate mass released was in the size range 0.1-1 pm. Sandberg and Martin 393 examined wood-fire smokes and reported single spherical submicrometre particles, chains of particles up to 4 pm long, solid near-spherical particles from 1-1 2 p m diameter, and solid angular particles up to 20 p m diameter. Some 80% of particles had aerodynamic diameters <0.3 pm.

-

R. Haulet, P. Zettwoog, and J. C. Sabroux, Nature (London), 1977,268, 715. T. C. Huang, N. D. Watkins, and D. M. Shaw, Deep Sea Res., 1975, 22, 185. 387 J . L. Stith, P. V. Hobbs, and L. F. Radke, J . Geophys. Res., 1978,83,4009. Iaa R. D. Cadle and E. J. Mroz, Science, 1978, 199,455. G. Crozat, J. L. Domergue, J. Baudet, and V . Bogui, Atmos. Environ., 1978, 12, 1917. I9O D. E. Ward and E. R. Eliott, J . Air Pollut. Conlrol Assoc., 1976, 26, 216. 19’ D. R. Packham and R. G. Vines, J . Air Pollut. Control Assoc., 1978, 28, 790. 392 L. F. Radke, J. L. Stith, D. A. Hegg, and P. V. Hobbs, J . Air Pollut. Control Assoc., 1978, 28, 30. 393 D. V. Sandberg and R. E. Martin, ‘Particle Sizes in Slash Fire Smoke’, USDA Forest Service Res Paper PNW-199, Portland, Oregon, 1975.

Environmental Chemistry

36

Characteristics of particles emitted from the combustion of different crop wastes and the emission factors have been described.394In Hawaii, burning the residues of sugar cane increased short-term particulate concentrations to 2000 pg mP3 at 0.5 km distance and 500 pg m-3 at 2.5 km downwind, compared to ambient values of 5 0 p g m-3.395 Plants.-In

tropical forests of the Ivory Coast, W. Africa, release of aerosols (d

<

0.5 pm) rich in K is reported, particularly at night during heavy g ~ t t a t i o nThe . ~ ~K~ is water soluble and is readily extracted from air filters. The release of Pb and Zn by leaf surfaces has been demonstrated by radioisotope experiments, possibly by surface bending and abrasion of leaves, with typical rates of release being -5 g of ~’ of plant organic Pb and 9 kg of Zn from 1 km2 vegetation ~ r - ’ . ~Decomposition residues in equatorial forest is believed to contribute significantly to the regional concentration of SO, that is liable to oxidation to form SO:- aerosols.398

-

Combustion of Fossil Fuels.-The magnitude of both particulate and gaseous emissions from coal-fired power plants has received detailed attention to establish input-output mass balances. At the Allen 870 MW(e) plant in Memphis, atmospheric discharges of 0.2-0.4 g min-l were found for As, Cd, Co, Pb, Sb, and Se.399Recovery of Hg in ashes was only -10% of the input in coal4O0and large amounts of B are also emitted to the atmosphere.401 At the Valmont coal-fired power station (180 MW) in Colorado, concentrations of As, Cu, Mo, Pb, Sb, Se, and Zn increased progressively through the flow stream, but concentrations of Al, Fe, Nb, Rb, Sr, and Y were fairly constant in all outlet Large enrichment factors relative to input coal are established for As, Sb, and Se in stack aerosols.403Using data from the Allen plant the combustion of 6 x lo8 US tons of coal yr-I would release the following tonnages of elements in particulate and gaseous form: Hg 60, Pb 12 000, Cd 240, As 3000, Se 3000, Sb 2400, V 15 000, and Zn 120 OO0.404 By 1990, US coal consumption is expected to increase seven times to 25 x 10’ tonnes yr-l, emitting -5.1 x lo6 tonnes of particulates yr-l, or 21% of the US anthropogenic emission inventory.405 Coal and coke burning facilities around the Gulf of Mexico are believed responsible for inputs of -65 x lo4 tonnes yr-l of black magnetic spherules, having a basic magnetite (Fe304)matrix, F. Darley, ‘Emission Factors from Burning Agricultural Wastes Collected in California’, Rep. ARB-R-001-77-59, Univ. California, 1977. 39J B. D. Root, W. Bach, and A. Daniels, J . Air Pollut. Control Assoc., 1975, 25,637. 3y6 G. Crozat, Tellus, 1979, 31, 52. 39’ W. Beauford, J. Barber, and A. R. Barringer, Science, 1977, 195, 571. 398 R. Delmas, J. Baudet, and J . Servant, Tellus, 1978, 30, 158. 39y D. H. Klein, A. W. Andren, J. A. Carter, J. F. Emery, C. Feldman, W. Fulkerson, W. S. Lyon, J. C. Ogle, Y. Talmi, R. I. Van Hook, and N. Bolton, Enuiron. Sci. Technol., 1975, 9,973. 400 G. W. Kalb, in ‘Trace Elements in Fuel’, ed. S. P. Babu, Am. Chem. SOC.,Washington DC, 1975, p. 154. 401 E. S. Gladney, L. E. Wangen, D. B. Curtis, and E. T. Jurney, Environ. Sci. Technol., 1978, 12, 1084. 402 J. W. Kaakinen, R. M. Jorden, M. H. Lawasani, and R. E. West., Enuiron. Sci. Technol., 1975, 9, 862. 403 R. C. Ragaini and J. M. Ondov, Rep. UCRL 77669, Lawrence Livermore Laboratory, Livermore, USA, 1977. 404 N. E. Bolton, J. A. Carter, J. F. Emery, C . Feldman, W. Fulkerson, L. D. Hulett, and W. S . Lyon, in ref. 400, p. 175. 405 J. M. Ondov, R. C. Ragaini, and A. H. Biermann, in ref. 148, p. 338. 3y4 E.

Inorganic Particulate Matter in the Atmosphere

37

into the E. Gulf area.4o6At Cape Bathurst in N.W. Canada, spontaneous burning of bituminous shales releases large quantities of As, Br, Sb, and Se that affects the surrounding tundra.407 The formation and characterization of submicrometre fly ash particles from coal-fired power stations is of concern owing to their potential for dispersion and i n h a l a t i ~ n . ~Bursting ~ ~ . ~ ~of~ large particles during gas expansion followed by coagulation may produce submicrometre fly ash particles for which chemical uniformity is reported for some 14 elements, including As, Hg, Pb, Se, V, and Zn.408 As the size range increases from 1-10 pm, concentrations of these elements but the reverse is noted for Ca, Sr, Y, and rare earths in the region of 5 p m diameter.410 Eleven distinct morphological types of coal fly ash particles have been identified,411 of which the finest fraction (d = 2.4 pm) consisted mainly of non-opaque glassy spheres and 8% cenospheres, while coarser particles consisted of 41% cenospheres and 26% non-opaque spheres; a fly ash morphogenesis scheme is presented to indicate particle relationships on the basis of shape and opacity. Although magnetic particles constitute only 1% of total fly ash they are highly enriched in metals, whereas the non-magnetic group contains more non-metals, being the silicate fraction.412Preferential concentration of Cl, S, and heavy metals in a thin surface layer on fly ash particles is related to coal type and combustion conditions 135*413,414 and is attributed to volatilization-condensation p r o c e ~ s e s . ~ ~ ~ . ~ ~ Collection of fly ash emissions to the atmosphere rather than sampling of material collected by control devices has been achieved by aircraft.136 A coal-fired power station released particulates with bimodal size distribution near to the stack (peaks at d = 0.04 and 0.25 pm), but this became unimodal at 5 miles downwind, possibly from coagulation during dispersion of the plume. 136 The effectiveness of particulate-emission-control devices have been compared for a coal-fired power plant, a steel plant, and a cotton gin with respect to the release of trace metals to the atmosphere.417Recent estimates indicate considerable differences in releases from major industrial processes, as shown for some metals in Table 3.418 Particulate emissions from combustion of heavy fuel oil showed relatively high concentrations of V but low C content in the submicrometre fraction, but the reverse was true for larger cenospheres from 10-50 p m diameter.419Problems of cleaning

406

L. J. Doyle, T. L. Hopkins, and P. R. Betzer, Science, 1976, 194, 1157.

407T. C. Hutchinson, W. Gizyn, M. Havas, and V. Zobers, in ‘Trace Substances in Environmental Health’, ed. D. D. Hemphill, Univ. Missouri, 1978, Vol. 12. R. D. Smith, J. A. Campbell, and K. K. Nielson, Atmos. Enuiron., 1979, 13, 607. 409 F. B. Meserole, K. Schwitzgebel, R. A. Magee, and R. M. Mann, Trans. ASME, 1979, 101,620. 410 J. A. Campbell, J . C. L a d , K. K. Nielson, and R. D. Smith, Anal. Chem., 1978, 50, 1032. 411 G. L. Fisher, B. A. Prentice, D. Silberman, J. M. Ondov, A. H. Biermann, R. C. Ragaini, and A. R. McFarland, Environ. Sci. Technol., 1978, 12,447. 412 K. H. Abel and L. A. Rancitelli, in ref. 400, p. 118. 413 R. Pueschel, Geophys. Res. Lett., 1976, 3, 65 1. 4 1 4 R. W. Linton, A. Loh, D. F. S. Natusch, C . A. Evans, jun., and P. Williams, Science, 1976, 191, 853. 4’5 J. A. Campbell, R. D. Smith, and L. E. Davis, Appl. Spectrosc., 1978, 32, 316. 416 J. A. Campbell, R. D. Smith, L. E. Davis, and K. L. Smith, Sci. TotalEnuiron., 1979, 12, 75. 4 1 7 R. E. Lee, jun., H. L. Crist, A. E. Riley, and K. E. Macleod, Enuiron. Sci. Technol., 1975, 9,643. 418 R. B. Jacko and D. W. Neuendorf, J . Air Pollut. ControlAssoc., 1977,27,989. 419 H. L. Goldstein and C. W. Siegmund, Environ. Sci. Technol., 1976, 10, 1109. 408

38

Environmental Chemistry

Table 3 Emission rates of trace metal particulate to the atmosphere (kg h-1)418 Industrial process

Size fraction R" Nh R N

Open hearth furnace, 400 ton capacity, no emission controls Open hearth furnace, 400 ton capacity, emissions control by electrostatic precipitator (ESP) Zinc sinter plant, cyclone and ESP controlled Municipal incinerator, 204 metric tons day-' capacity, scrubber controlled Coal-fired power station, 220 000 kg h-' steam, ESP controlled

Cd 0.066 0.063 0.0016 0.000 46

Pb 8.9 2.8 0.11 0.033

Zn 40 12 0.72 0.29

TSP 198 79 4.5 1.1

R N R N

5.1 3.4 0.039 0.02

3.5 2.5 1.1 0.15

6.3 6.7 2.4 0.98

26 39 9.9 16

R N

0.000 37 0.000 80

0.029 0.078

2.9 14

a R = respirable fraction <2 pm aerodynamic diameter; aerodynamic diameter.

-

-

N

=

non-respirable fraction > 2 p m

up oil spills in the Canadian Arctic prompted research on metal and soot emissions from burning in sit^.^^' Particulate emission factors from wood-burning stoves were from 2.5-7.5 g kg-', relatively large during the smouldering stage and greater for pine than oak Other Industrial Processes.-Incineration of municipal refuse is an important source of particles that are enriched in Ag, Cd, In, Sb, Sn, and Zn, mainly in the smaller size fraction, d < 2 An enrichment of surface layers of particles has been reported for K, Mn, Ni, and S.423Although the use of refuse incinerators is decreasing in the US,424refuse-derived fuel may be used in future in power stations; burnt with coal, emissions of As, Be, Cd, C1, and Pb are increased but Hg, S, and Se are decreased relative to coal In the UK, modern incinerators release -0.5-1.5 kg of particulates per ton of refuse, or an order of magnitude less than emissions from older installations built before 1960.426 Enrichments of several elements including Ag, As, Cd, Sb, Se, and Pb are reported in particulate emissions from lead smelters.427In flue dusts from copper and lead smelters the following were identified: As203,PbSO,, PbO PbSO,, ZnO, Fe304, and Fe203.428Gold smelting industry at Yellowknife, N.W. Canada, has released 19 000 long tons of As to the atmosphere between 1947 and 1974: rapid condensation of As,O, vapour and deposition of particulate As is indicated.429 T. Day, D. Mackay, S. Nadeau, and R. Thurier, Water Air Soil Pollut., 1979, 11, 139. S. S. Butcher and D. I. Buckley, J. Air Pollut. Control Assoc., 1977, 21, 346. 422 R. R. Greenberg, W. H. Zoller, and G. E. Gordon, in ref. 30, p. 8 17. 02' J. J. Singh, Rep. NASA-TM-78630, 1978. 424 R. R. Greenberg, G. E. Gordon, W. H. Zoller, R. B. Jacko, D. W. Neuendorf, and K . J. Yost, Environ. Sci. Technol., 1978, 12, 1329. 425 H. R. Shanks, J . L. Hall, and A . W. Joensen, in ref. 30, p. 739. 4 2 6 M. J. Fisher, Clean Air, 1978, 8, 5. 427 R. C. Ragaini, H. R. Ralston, and N. Roberts, Enuiron. Sci. Technol.', 1977, 11, 773. 4 2 8 D .J. Eatough, N. L. Eatough, M. W. Hill, N. F. Mangelson, J. Ryder, L. D. Hansen, R. G. Meisenheimer, and J. W. Fischer. Atmos. Environ., 1979, 13,489. 429 D. Hocking, P. Kuchar, J. A. Plambeck, and R. A. Smith, J . Air Pollut. Control Assoc.. 1978, 28, 133. 420

42'

Inorganic Particulate Matter in the Atmosphere

39

Scrap metal recovery factories may be an important source of Cd and Pb in the atmosphere, with dust from households near to such industry showing 190 pg Cd g-’ and 3400 pg Pb g-1.430Phosphorus reduction plants that use fluorapatite ore can release Be, Li, Pb, U, V, and Zn in addition to particulate and gaseous Evaporative cooling systems of power-generating stations may release drift droplets and mineral residues to the atmosphere, which is particularly significant if zinc phosphate or chromate compounds are circulated as ~ c a l e - r e t a r d a n t s .High ~~~ pm) and ‘giant’ (d > 1 pm) concentrations of particles, both ‘large’ (d = 0.1-1 have been found in emissions from a paper mill, with evidence of particle coagulation occurring in the plume at 7 km distance.434

F.4319432

Emissions from Motor Vehicles.-Primary exhaust aerosols are produced within the size range 0.01-0.1 pm and photochemical reactions may lead to the formation of secondary aerosols in the submicrometre range.273*435 Although the Pb is added to motor fuel in organic form as tetraethyl- or tetramethyl-lead, the particulate emissions are composed of inorganic oxides, sulphates, halides, and carbonates. The eventual particle-size range of this aerosol is affected by coagulation with the urban aerosol, which may result in particles up to 5 pm diameter.436Aerosol sampled by the M4 motorway in London contained an opaque, discrete rounded fraction (d < 0.1 pm), diaphanous chain aggregates (d = 0.1-1 pm), and larger dense flaky or amorphous particles (d = 0.5-5 pm) mainly of carbonaceous origin.436 Quantitative aspects of the release of Pb from motor vehicles are reviewed: it is estimated that for a traffic flow of 100 vehicles h-l, the output of Pb is 10 mg s-’ km-l (assuming 0.49 g Pb 1-’ in petrol and 0.24 1 consumption, with 75% emission).436About 6-10% of Pb emitted is generally deposited within 100-1 50 m from the m o t o r ~ a y . ~ ~In’ ,the ~ ~aged * (48 h) exhaust aerosol, (NH,),SO, - PbSO, has been identified as a major constituent, with PbSO, and PbBrCl present as minor components.439Photochemical and other factors that influence the formation of Pb compounds from vehicle exhaust are discussed ~ e p a r a t e l y . ~ The ~ ~ ratios , ~ ~ ~ of Br :Pb in exhaust emissions are closely related to the fuel formulation, so that in Perth, W. Australia, ratios of 0.61 and 0.59 are found in motor spirit and in air particulate, respectively, while in the US lower ratios of 0.39 and 0.29 have been

C. J. Muskett, L. H. Roberts, and B. J . Page, Sci. Total Environ., 1979, 11, 73. L. K. Thompson, S. S. Sidhu, and B. A. Roberts, Environ. Pollut., 1979. 18. 221. 4 3 2 R. C. Severson and L. P. Gough, J . Environ. Qual., 1976, 5, 476. 4 3 3 F. G. Taylor, jun., L. K. Mann, R. C. Dahlman, and F. L. Miller, in ‘Cooling Tower Environment 1974’, USERDA Conf. 740302. NTIS, Springfield. VA, 1975. p. 408. 4 3 4 E. E. Hindman 11, P. V. Hobbs. and L. F. Radke, J . Air Pollut. Control Assoc., 1977, 27,224. 4 3 5 D. F. Miller, A. Levy, D. Y. H. Pui, K. T. Whitby, and W. E. Wilson, jun., J . Air Pollut. Control Assoc., 1976, 26, 576. 43h A. C. Chamberlain, M. J. Heard, P. Little, and R. D. Wiffen, Philos. 7rans. R . SOC.London, Ser. A , 1979,290,577, 4 3 7 J . J. Huntzicker, S. K. Friedlander, and C. I. Davidson, Environ. Sci. Technol.. 1975, 9, 448. P. Little and R. D. Wiffen, Armos. Environ., 1978, 12, 1331. 43y P. D. E. Biggins and R. M. Harrison, Nature (London),1978, 272, 53 I . 44u R. M. Harrison and R. Perry, Atmos. Environ., 19’18, 12, 957. 4 4 1 P. D. E. Biggins and R. M. Harrison, Enilirotz. Sci. Techno/., 1979, 13, 558. 442 B. H. O’Connor. G. C. Kerrigan. W. W. Thomas. and A. T. Pearce, Atmos. Enriron., 1977. 11, 635. 43u 431

”’

40

Environmental Chemistry

An alternative to the use of Pb-halide compounds in motor fuel as ‘anti-knock’ additives is ‘MMT’ (methylcyclopentadienyl-Mn tricarbonyl), which results in exhaust emissions of Mn 304.443 Typical emission rates from vehicles powered with petroleum spirit were 0.08 mg Mn km-I in 1977, or -15% of the Mn added to the Exhaust from a light-duty diesel engine released -0.15 g particulates km-I at 60 km h-I, consisting of 60-75 wt% organic compounds and <1% SO:- and metals.445The emission of SOP aerosols by catalyst-fitted vehicles in the US was 8 mg km-l, or an order of magnitude greater than from non-equipped vehicles.446In the case of diesel trucks, 44 mg SO:- km-’ was released together with SO,.446 Source Identification Studies and Methods,-The identification of natural and man-made sources of air particulates in rural atmospheres and estimation of relative strengths of particulate pollution sources in urban areas has received further attention by the application of improved analytical and statistical techniques. Microscopical analysis of particles collected on high-volume air filters at rural and urban sites in the US showed the following percentage contributions from four main categories of sources for organic and inorganic particulate^:^^'

(i) minerals, 72-9 1940, e.g., soil particles, haematite, mica, and talc; (ii) combustion products, 1-lo%, e.g., coal and oil soot, fly ash, burned paper, and vegetable matter; (iii) biological materials, 2-lo%, e.g., pollen, spores, paper, starch, plant tissues, and diatoms; (iu) miscellaneous matter, trace-8%, e.g., salt, rubber, iron/steel, paint pigment, and humus. Gatz448 described the selection of tracer elements for each major source contributing to the urban aerosol, as a first step in the calculation of source co-efficients to obtain quantitative estimates of inputs from various types of emission. Corrections are made for secondary sources of an element. Thus Gatz448 estimated the following source contributions to the total Chicago aerosol: automobile (primary emissions) 2.8%, fuel oil 1.4%, cement manufacture 3.2%, steel manufacture 3.9%, coal burning 6.4%, soil dust 18%, sulphates 11.5%, and nitrates 5.3%. Contributions of air pollution sources to TSP in New York aerosol have been calculated by a regression analysis model, using the source-tracer elements: Pb for automobiles, V for fuel oil emissions, Cu for incineration, Mn for soil, and SO:- for oxidation of SO, from local or distant sources.449The independent (or predictor) variables, i.e., levels of 11 metals in air, were initially examined by factor analysis, G. I. Ter Haar, M. E. Griffing, M. Brandt, D. G. Oberding, and M. Kaprou, J . Air Pollut. Control Assoc., 1975, 25, 858. 444 W . R. Pierson, D. E. McKee, W . W. Brachaczek, and J. W. Butler, J. Air Pollut. Control Assoc., 1978,28,692. 445 A. Laresgoiti, A. C. Loos, and G. S . Springer, Environ. Sci. Technol., 1977, 11,973. 446 W. R. Pierson, W. W. Brachaczek, and D. E. McKee, J . Air Pollut. Control Assoc., 1979, 29, 255. 447 E. W. Klappenbach and S. K. Goranson, ‘Ann. Meeting Air Pollut. Control Assoc.’, Toronto, June 1977, paper 77-4.6. 448 D. F. Gatz, Atmos. Environ., 1975, 9. 1. 449M.T. Kleinrnan, B. S . Pasternack. M. Eisenbud, and T. J . Kneip, Environ. Sci. Technol., 1980, 14, 62. 443

Inorganic Particulate Matter in the Atmosphere

41

which revealed ‘clusters’ or associations and enabled selection of individual tracer elements for specific sources. This model allocated -75% of TSP levels to the nominated sources with some 20-25% of this attributed to automobiles, -40% from natural or secondary sources, 10% from fuel oil burning, and 5% from incineration. Similar approaches have been made with data from other rural and urban areas in the US,450-455 sometimes using different combinations of tracer elements. By application of emissions factor data for various sources to Belgian industry it has been estimated that combustion accounts for 2 1% of total particulate emissions and metallurgical industries emit 50%, but for small particles (d < 10 pm) combustion accounts for 33%, metallurgy 18%, and the cement industry 28%.456A method of labelling pollutant sources with stable rare earth elements Ce, Dy, La, and Sm, has been applied to several industries to evaluate source contributions and dispersion patterns;457these elements are analysed by neutron-activation. Changes in the isotopic ratio of natural 34S:32Sin fuel oil may be used to follow oxidation reactions of SO, emitted from a power Further studies on the increase in S :C1 ratios in marine aerosols relative to ratios in bulk seawater have been made by using 34S:32Sratios to differentiate between a sea-spray source and a biogenic source of S.459 Sulphur compounds of biogenic origin, such as H,S and (CH,),S, show lower ratios of these isotopes than fossil-fuel sources or bulk seawater. Consequently, the low ratios in Californian marine aerosols are only compatible with biogenic origin.459 A high pollution episode in Greater London during 2 days in December 1975, when hourly smoke concentrations approached 1000 ,ug m-3, was examined by a long period average dispersion model to estimate major sources of emission; this showed that over 30% of the smoke levels were contributed by motor vehicles, 24% by combustion of domestic solid smokeless fuel, 17% by domestic coal burning, and 20% by pollution sources outside London.460A recent study of smoke (and SO,) concentrations in the Forth Valley, Scotland provided comprehensive emission inventories for domestic and industrial sources.461The contribution of motor vehicles and domestic emissions to dark smoke levels in Greater London, as recorded by smoke-shade measurements, was estimated from Pb concentrations and TSP levels: on this basis vehicle emissions contributed 77-89% to dark smoke concentrations.462 450G.M. Hidy, B. R. Appel, R. J. Charlson, W. E. Clark, S. K. Friedlander, D H. Hutchinson, T. B. Smith, J. Suder, J. J. Wesolowski, and K. T. Whitby, J . Air Pollut. Control Assoc., 1975, 25, 1 106. 4 5 ’ P. K. Hopke, E. S. Gladney, G. E. Gordon, W. H. Zoller, and A. G. Jones. A m o s . Environ., 1976, 10, 1015. 4 5 2 H. E. Neustadter, J. S. Fordyce, and R. B. King, J . Air Pollut. Control Assoc., 1976, 26, 1079.

P. D. Gaarenstroom, S. P. Perone, and J. L. Moyers, Environ. Sci. Technol., 1977, 11, 795. D. F. Gatz, in ref. 30, p. 443. J 5 5 G . S. Kowalczyk, C. E. Choquette, and G . E. Gordon, Atmos. Enciron.. 1978. 12, 1143. 45b M. Demuynck, Water Air Soil Pollut., 1975, 5, 3 . 4 s 7 Y. S. Shum, W. D. Loveland. and E. W. Hewson, J . Air Pollut. Control Assoc., 1975. 25. 1123. 4J8 L. Newman. J . Forrest, and B. Manowitz. A m o s . Enz1iron.. 1975,9. 959. 4 5 9 F. L. Ludwig, Tellus, 1976, 28,427. 460 A. J. Apling, A. W. C. Keddie, M. Weatherley, and M. L. Williams. Warren Spring Laboratory Rep. LR 263(AP), Stevenage, 1977. 4 6 1 A. W. C. Keddie, J. S. Bower, R. A. Maughan. G. H. Roberts, and F. P. Williams. Warren Spring Laboratory Rep. LR 278(AP), Stevenage. 1978. 46* D. J. Ball and R. Hume, Amos. Enoiron.. 1977, 11, 1065. 453

4s4

42

Environmental Chemistry 5 Atmospheric Transport and Dispersion of Particulates

Transport and dispersion of particulate material in the atmosphere may occur on a global scale by vertical transport, meridional circulation, eddy mixing, stratosphere-troposphere interchange, and inter-hemisphere exchange. Regional scale transport of particulates is usually interpreted as movement up to 1000 km from the source, and movement up to 100 km distance is termed local. Regional and Long-distance Transport.-The transport of SO, and associated particulate SO:- pollutants has been a major field for research, as reviewed by W h e l ~ d a l e .In ~ ~1977, ~ a summary report on the long-range transport of air pollutants (LRTAP)464throughout ten countries in Europe concluded that in half of them the major fraction of S deposition from the atmosphere originated outside their borders. In areas of greatest SO, emission, the total S deposition estimated from dispersion models was 10 g S m-*, with a dry :wet deposition ratio of 1.7.464 Furthermore it appears that -20% of S emissions occurring within the European study area was ‘exported’ by long-distance transport processes.464Similar work is in progress in Canada and the US (Multi-State Atmospheric Power Production Pollution Study MAP3 S).465 Wilson466has reviewed results from project ‘MISTT’ (Midwest Interstate Sulphur Transformation and Transport), and implementation of ‘SURE’ (Sulphate Regional Experiment) in the N.E. region of the US is detailed by per ha^.^^' It has been concluded from monitoring at coastal sites in Denmark, Germany, and England that air trajectories from the continent are responsible for increases in ground concentrations of smoke, SO:-, and NO; in E. England.468Long-distance transport of Pb to Denmark is held to account for -70% of total (dry + wet) deposition of Pb in rural areas, away from roads, and air-mass trajectories from the UK and Central Europe gave precipitation with relatively high Pb content.469Laser radar systems have been successfully used to track dispersion of industrial emissions over long d i s t a n ~ e s . ~Furthermore, ~~.~~’ the urban plume from St. Louis, Missouri, was detected as far as 120 km downwind by differences in particle-size spectra of air particulate relative to background air.472 Studies on transport of air particulates from natural sources have been mainly concerned with the movement of soil dust. Research into the mobilization and long-distance transport of Sahara dust and the ecological and climatological implications has been reported at a recent workshop,362with particular reference to mineral dust loadings in the N.E. trade wind towards the Caribbean Sea, some 5000 km from the source. The estimated source strength of the Sahara is 260 x lo6tons

-

D. M . Whelpdale, M A R C Rep. No. 7. SCOPE/ICSU. Chelsea Coll.. Univ. London. 1978. O E C D Programme on Long Range Transport of Air Pollutants, Measurements and Findings, O E C D , Paris. 1977. 4b5 D. M. Whelpdale, Atmos. Environ., 1978, 12.66 1. ‘tx W. E. Wilson. Atmos. Eni3iron.. 1978. 12. 537. 4 h 7 R. Perhac. Rep. EA- 1066, Electric Power Res. Inst.. Palo Alto. CA, 1979. 4hH R. A. Barnes and A. E. J. Eggleton. Atmos. Enitiron.. 1977. 11. 879. 4h9 M. F. Hovmand, Tellus, 1980, 32.42. 47” E. V. Browell, in ref. 30, p. 395. 4 7 1 E. E. Uthe and W. E. Wilson, in ref. 30. p. 407. 412 J. F. Stampfer, jun. and J. A . Anderson, Atmos. Enisiron., 1975. 9. 301. 461

4h4

Inorganic Particulate Matter in the A tmosphere

43

Figure 3 Estimated trajectory f o r transport of Sahara dust to Ireland and the U K , March 1977. Pressure levels (mbar) o f t h e isentropic surface 8 = 300 K f o r 0001 GMT, 6th March 1977. . . . . trajectory of air assuming motion along 700 mbar surface and ---- trajectory of air assuming isentropic flow along 8 = 300 K surface. Position of air marked bj! or x refers to 000 1 GMT. (Reproduced by permission from Weather, 1978, 33,48)

44

Environmental Chemistry

yr-I of mineral dust and even after 1000 km trajectory the deposition to the ocean is -39 x lo6 tons yr-1.473L e ~ p l considered e ~ ~ ~ the chemical effects of this aeolian input of Si and phosphate to the N.E. Atlantic, while Johnson475reviewed the occurrence of sea haze from windborne soil dust and reported that in the N.E. trade winds dust loadings were 4 orders of magnitude greater than in N. Atlantic westerlies. Transport of Sahara dust to the UK occurred in 1968 and more recently in March 1977 when depositions were noticed in N. Ireland and the Isle of Skye, with an estimated trajectory as shown in Figure 3.47hA heavy fall of dust took place in E. and S.E. Europe in April 1973 from an air mass which passed over N. Africa 2 days before.477Sahara dust can reach an altitude of 5000 m by association with European polar front depressions.478 Measurements of air conductivity with balloon-borne radiosondes indicate 1500 pg rnp3 of Sahara dust in air in a dust layer over the N. Atlantic at altitudes between 1.2-3.7 km.479The dust outflow from N.W. Africa has been tracked by satellite from measurements of nadir radiance,480 by the SMS- 1 (synchronous meteorological satellite), which takes pictures with 2-4 km resolution in the visible spectrum116 and by a network of land- and ship-based stations over the entire equatorial N. Atlantic Ocean.'I3 Particle trajectories for dust storms in the E. Mediterranean region indicate that 20-30 x lo6 tons yr-l is transported from the deserts of Libya, Egypt, Sinai, and the Negev to be deposited mainly into the Mediterranean Sea, although significant deposits of loess are found in Israeli soils.481Dust plumes that pass over Alaska are estimated to transport 0.5 x lo6 tons of particulates in a 5 day episode of poor visibility, and originate by resuspension of desert soils of E. The seasonal transport of soil dust ('Kosa') from N. China to Japan was shown to alter the particle-size distribution of urban aerosols in Nagoya, introducing a coarser fraction with mean diameter 5.8 p m that contained 95% of the total Al and Si present.482 The role of wind in dispersion of specific pollutants has received attention with respect to fluctuations in SO, levels in Toronto483and the occurrence of acute Seasonal pollution episodes in rural areas up to 80 km from industrial differences in TSP concentrations in New York City are far more apparent when the data is normalized for effects of wind speed and height of the atmospheric mixing layer.485Deterioration of air quality in slow moving high-pressure systems is

"' R. Jaenicke, in ref. 362, p. 233. F. Lepple. 'Eolian Dust Over the N . Atlantic Ocean'. Ph.D Thesis, Univ. Delaware, 1975. L. R. Johnson, Mur. Obs. 1978, 48, 23. 476 M. T. Tullett, Weather. 1978, 33. 48. 47' K. Cehak. Weiler Leben. 1976, 28. 9 1. 4 7 x J . Dubief, in ref. 362. p. 27. 47y W. Gringel and R. Muhleisen. Beitr. Phis. Afntus.. 1978. 51. 121. 4xu R. S. Fraser. Appl. Optics, 1976. 15, 2411. 4x' D. H. Yaalon and E. Ganor, in ref. 362. p. 187. 482 S. Kadowaki. Eniiiron. Sci. Technol., 1979. 13. 1 130. B. Padmanabhamurty, J . Air Pollui. Conirol Assoc.. 1975. 25. 956. 4n4 C. Ronneau. J. L. Navarre. P. Priest. and J. Cara. A ~ m o s En~~iron.. . 1978, 12. 877. 4 x 5 M. T. Kleinrnan. T. J. Kneip, and M., Eisenbud. Atmos. Ewiron.. 1976, 10. 9. 474 475

Inorganic Particulate Matter in the A tmosphere

45

related to increases in TSP and gaseous pollutants in eastern US regions486and increases in particulate NO, in S. Ontario.487

Dispersion Modelling.-Air-quality modelling has been studied extensively over the last few years to evaluate the effect of particulate (and gaseous) emissions on ambient air quality and compliance with national standards.488A guideline on the use of air-quality models is now available,489 and a users network for applied modelling of air pollution (‘UNAMAP’) offers 11 types of dispersion models, which are all based on the Gaussian modelling approach that is best suited to relatively inert plumes where gas-to-particle conversion is not taken into account.490Turner491 has recently published a critical review covering photochemical modelling, improvement, and evaluation of models. To facilitate the estimation of pollutant dispersal on a regional scale from industrial areas representing a continuous source, M a ~ h t has a ~ ~prepared ~ a valuable guide to derive the seasonal ground-level air concentration, deposition rate, horizontal flux, and the magnitude and probability of peak air concentrations and deposition. Changes in the vertical structure and turbulence of the atmospheric boundary layer affect estimates of dispersion and dilution of pollutants, and the importance of temperature inversions as barrier layers for turbulent exchange is r e c ~ g n i z e d . ~ ~ ~ . ~ ~ The fundamental principles of air pollution meteorology and problems encountered in studies on regional scale dispersion are reviewed by M ~ n n Plume-rise . ~ ~ ~ studies are notoriously difficult owing to atmospheric turbulence effects: for example, building-plume interactions can increase turbulent mixing and downwash with the result that ground-level air concentrations may increase by 2 to 5 fold.496Plume dispersion in wind-tunnel experiments may be compared with theoretical prediction^.^^' Improvements in the assessment of plume-rise by a puff-diffusion model, with consideration of wind-shear effects, are recommended for situations exposed to lake or sea breezes where unsteady dispersion and non-uniform flow conditions are experienced.498Acoustic radar is being applied to define the heights of inversion bases and the vigour of atmospheric mixing processes at various stages in a pollution episode499.500and also to ‘TAPAS’ (Topographic Air Pollution

F. M. Vukovich, Atmos. Environ., 1979, 13, 255. K. C. Heidorn, Water Air Soil Pollut., 1979, 11, 225. 488 Papers in ‘Proc. 4th Symp. Turbulence, Diffusion and Air Pollution’, Am. Met. SOC.,Boston, 1979. 48y ‘Guidelines on Air Quality Models’, Rep. EPA-450/2-78-027, US Environ. Protection Agency, N. Carolina, 1978. 4y0 D. B. Turner and A. D. Busse, in ‘Proc. 8th Int. Tech. Meeting Air Pollution Modelling and Application’, NATO, Brussels, 1977, p. 248. 4 q ‘ D. B. Turner, J . Air Pollul. Control Assoc., 1979, 29, 502. 4q2 L. Machta, MARC Rep. No. 11, Chelsea Coll., Univ. London, 1979. 493 ‘Boundary Layer Climates’, T. R. Oke, Methuen, London, 1978. 4y4 W.M.O. Rep. 510, Geneva, 1978. 4 y 5 R. E. Munn, in W.H.O. Spec. Publ. No. I , Copenhagen, 1976, p. 101. 4q6 D. J. Wilson and D. D. T. Netterville, Atmos. Environ., 1978, 12, 1051. 4q7 A. G. Robins, Almos. Environ., 1978, 12, 1033. 498 C. M. Sheih, Atmos. Environ., 1978, 12, 1933. 49y P. B. Russell and E. E. Uthe, Atmos. Environ., 1978, 12, 1061. 500 R. B. Hicks and T. Mathews, Water Air Soil Pollut., 1979, 11, 159. 486 481

46

Environmental Chemistry

Analysis System). which is a box model designed for mountain valley airsheds where inversions are f r e q ~ e n t . ~ " Dispersion modelling of pollutants in regions with significant topography or land-sea effects is achieved by an 'overlay technique', whereby each receptor height in a grid of 11 km side is classified into a topography layer: data from this is used to modify a standard climatological dispersion model to improve correlations between observed and predicted concentrations of TSP at ground level.so2For modelling the dispersion of particulate pollutants near motorways, a simple line-source model is proposed as an alternative to the conventional 'HIWAY' line-source model, to consider the effects of mechanical mixing and plume rise owing to heated exhaust.503-505Recommendations for modification of point-source-plume models (Pasquill-Gifford system) have been made with special reference to dispersion of pollutants from airport sources.5o6 A grid-based mesoscale air-quality model has been applied to assess visibility and SO:- dispersion from a coal development area in the US."' Trajectory models were less suited to this multiple-source situation than the Eulerian approach, and results were expressed in terms of predicted surface uptake, scattering coefficients, and visual ranges.507 Modelling and budgeting the transfer of SO:- and gaseous S pollutants over W. Europe is discussed by Smith and Hunt,508together with problems arising in analysis of air trajectories. In the US, SF, has been used to trace pollutant trajectories and dispersion processes in the development of a large-scale atmospheric diffusion model for a power station.509The suitability of data bases needed for modelling the dispersion of plumes from tall-stack emissions and a list of intensive field projects on several industrial plants in Canada and the US are surnmari~ed.~'~ The effects of dry deposition and washout by rain on plume depletion, particularly of SO:- aerosols and SO, are evaluated by several workers to improve the accuracy of long-distance transport r n o d e l ~ . ~ ' Application of a short-term local urban air-quality model to predict SO:- and SO, concentrations was improved by consideration of both a first-order 'decay' (oxidation) process for SO, and a second-order catalytic oxidation possibly caused by V,O, coatings on fly ash particles or by Fe2+,Fe3+,and Mn2+.,I5 Global-circulation models have been used to study the dispersion of volcanic

E. A. Howard and D. G. Fox, in ref. 488. p. 182. J. W. S. Young. in ref. 41. p. 193. '03 D. P. Chock. Atmos. Etiuiroti.. 1977. 11. 553. 5'4 D. P. Chock. Artnos. Environ., 1978. 12. 823. 'OS S. H. Cadle. D.P. Chock, P. R. Monson. and J. M. Heuss. J. A i r Pollut. Corilrol Assoc.. 1977. 27. 33. snh F. Pasquill. J . A i r Pollut. Control A s s or... 1979. 29. 1 1 7. "" C. Shepherd Burton and M. K. Liu. in ref. 41. p. 187. "* F. B. Smith and R. D. Hunt. Philos. Trails. R. Sor. London. Ser. A . 1979. 200. 523. '09 B. K. Lamb. A. Lorenzen. and F. H. Shair,A/rnos. Er?viron.. 1978. 12. 2089. 'Ir' K. C. Sclarew and A. Joncich. Rep. EA-I 159. Electric Power Res. Inst.. Palo Alto. CA. 1979. '" R. A. Scriven and B. E. A. Fisher. A/mos. Em?irot?..1975, 9. 49. 5 1 2 T. A. McMahon. P. J . Denison. and R. Fleming. Artnos. Enviroti.. 1076. 10. 75 I . '" R. R. Draxler and W. P. Elliott.A/mos. Enuiror?.. 1977. 11. 35. 5 ' 4 L. P. Prahm and R. Berkowicz. Nature (Lorldot~). lc)78. 271. 232. ' I 5 A. R. Laird and R. W. Mikbad. J. A i r Polhit. Coritrol Assoc.. 1979. 29. 147. ''I

"I2

Irzorganic Particulate Matter in the Atmosphere

47

emissions and penetration of this material to the ~tratosphere.”~5 1 x Hudson and Reed241 have reviewed stratospheric aerosol models developed to examine nucleation, vapour condensation-evaporation, coagulation, sedimentation, and transport processes. Cycling of Elements and Global Inventories.-Cycling of atmospheric trace metals has been considered on both regional and global bases to examine the relative importance of disturbances to natural cycles caused by artificial inputs of elements that may function as nutrients or pollutants. In a global context, estimates of particulate inputs to the lower troposphere from natural and anthropogenic sources are summarized by Dittberner.’” For an estimated anthropogenic input of particulates (d < 5 pm) of 692 x lo6 tonnes yr-I, 47% is attributed to use of fossil fuels, 26% to man’s ‘energetics’ (i.e., soil dust raised by agricultural activities), and 20% to agricultural burning. The natural input, which is estimated at 1093 x lo6 tonnes yr-l, is mainly from sea spray (46%), wind-blown dust (1 l%), and natural decay processes that give rise to NO,, SO:-, and hydrocarbons. A volcanic input of dust and SO:- is separately estimated at 67-405 x lo6 tonnes yr-’.’I9 Thus from a grand total of 1852-2 190 x lo6 tonnes yr-’ some 32-37% of particulates originate from input by man. Junges20 estimated tropospheric dust burdens of 3 x lo6 tons in the N. hemisphere and 1 x lo6 tons in the S. hemisphere with possible additional contributions from the Sahara plume of 1 . 2 4 x lo6 tons. A relatively small urban area such as Perth, Australia was reported to generate a total particle flux of 4 x lOI9 s-’, which is relatively large compared to natural sources of the region.’,’ The residence time for tropospheric aerosols with mean d = 0.3 p m is between 18 and 96 days depending on the altitude of injection, and while dry deposition is more important than precipitation scavenging in the removal of low-level emissions, the reverse is true for aerosols in the mid to upper troposphere.522 In the upper stratosphere and mesosphere residence times of 5-10 yr are indicated by the behaviour of debris from high-yield nuclear weapons that penetrate the t r o p o p a ~ s e . ’For ~ ~ aerosols in the lower polar stratosphere, residence times of 2-4 months are usual, increasing to 6-12 months for the tropical lower stratosphere and to 1-4 yr for the mid-~tratosphere.’~~ days For SO:- aerosols, the average tropospheric residence time is 3-8 compared with 1-3 days for the precursor Average residence times of S compounds in the atmosphere in a temperate climate are discussed by R ~ d h e ’ ,and ~ by Schwartz.’,’ In a study of the regional residence times of SO, in the mixing layer R. D. Cadle. C. S. Kiang, and J. F. Louis. J . Geophys. Res., 1976. 81. 3125. R. D. Cadle. F. G . Fernald. and C. L. Frush.J. Geophys. Rrs., 1977. 82. 1783. ‘Ix B. G . Hunt, Monthly Weather Reis.. 1977. 105. 247. 5 1 y G. J. Dittberner, in ‘Proc. Conf. Climate and Energy‘. Am. Met. SOC.. Boston, 1978. p. 101. C. Junge. in ref. 362. p. 49. E. K. Bigg and D. E. Turvey, A/mos. Enuiron., 1978. 12. 1643. A . Marenco and J . Fontan. U S E R D A Symp. Ser. No. 38. NTIS, Springfield, VA, 1976, p. 54. D. H. Peirson. in ‘The Ecology of Resource Degradation and Renewal‘. ed. M. J. Chadwick and G . T. Goodman. Blackwell. Oxford. 1975. p. 81. 5’J A. D. Christie. in ref. 523. p. 91. H. W . Georgii. Dev. A~ntos.Sci.. 1979. 10. 18 1. H. Rodhe. Atmos. Etiuirow., 1978. 12, 67 1. 5 2 ’ S .E. Schwartz. Tellus, 1979. 31, 530.

‘I”

‘I’

’*’

’** ’*’

’’’

Environmental Chemistry

48 Table 4 Estimated worldwide emissions of trace Period

1850 to 1900 1901 to 1950 1951 to 1980 Annual

Global eriiissiorisfroin anthropogeriic sources ( x lohkg)

Cd

cu

Pb

19 73 162

92 5 14 1250

1100 5395 10 663

Ni 12 179 812

Zn 84 1 3212 7138

Global emissions from natural sources ( x lo6 kg) 0.83 19 26 25 44

under conditions in the eastern US,528data on microphysical removal processes showed that scavenging is generally more efficient in continental rather than maritime cloud. In the stratosphere, a residence time of 1 1.7 months was calculated for SO:- aerosol derived from the Fuego volcanic er~ption,’~’ in good agreement ~ ~ ~residence with lidar observations of decreases in aerosol b a ~ k s c a t t e r i n g .The times of stratospheric pollutants in general and the effects of Hadley circulation and large-scale eddies on stratospheric-tropospheric exchange processes are reviewed by Reiter.529 In an industrialized region it was concluded that the residence time of suspended particulate material in the atmosphere is between 5-16 h,530but is of course dependent upon weight-size distributions of the aerosol. Residence times of heavy metals in the atmosphere (generally <40 days) have been compared with behaviour in the hydrosphere, in soil, and in man.531The global tropospheric residence time of As is - 9 days, with a tropospheric burden of 7.7 x 10* g As and a global source strength of 31 x lo9 g As yr-I, from a detailed consideration of natural and anthropogenic sources and fluxes of the element.532 The global release of metals to the atmosphere from anthropogenic sources and dispersal to terrestrial and marine environments have been estimated (Table 4),533 these releases being enhanced by contributions from natural emissions such as sea-spray, soil dust, and volcanic eruptions, in addition to volatilization (de-gassing) of rocks which may be important for Cd, Cr, Hg, Sb, Se, and Zn.534Comparison of observed enrichment factors for trace metals in air particulate with values predicted from estimates of surface to atmosphere transfer rates has shown higher enrichments for the atmophile metals notably As, Hg, and Se, at high latitudes of Norway and Antarctica, and an additional flux from the sea surface to the atmosphere is Comprehensive volumes are available on the global cycling of Cd,536C U , ~ ~ ’ T. Henmi, E. R. Reiter, and R. Edson, Rep. EPA 600/4-78-003, Univ. Colorado, 1978. E. R. Keiter, Rev. Geophys. Space Phys., 1975, 13,459. 5 3 0 D. M. Whelpdale, Water Air Soil Pollut., 1974. 3, 293. 5 3 1 H. J. M. Bowen. in ‘Proc. Int. Symp. Heavy Metals in the Environment’, ed. T. C. Hutchinson, Univ. Toronto Press, 1975, Vol. 1, p. I . s 3 2 P. R. Walsh, R. A. Duce, and J . L. Fasching, J . Geophys. Res., 1979,84, 1719. s 3 3 J . 0. Nriagu, Nature (London), 1979, 279,409. 5 3 4 G. Desaedeleer and E. D. Goldberg, Geochem. J . , 1978, 12, 75. J’s R. J. Lantzy and F . T. Mackenzie, Geochim. Cosmochim. Acla., 1979,43,5 1 I. ”‘‘Cadmium in the Environment’, ed. J . 0. Nriagu, Wiley, New York. 1979. ’j7 ‘Copper in the Environment’, ed. J. 0. Nriagu, Wiley, New York, 1979. 52”

529

Inorganic Particulate Matter in the Atmosphere

49

Hg,538 Pb,53YS,540 and Zn 5 4 1 with detailed discussion of tropospheric transfer pathways. The environmental inorganic chemistry of both major and trace elements has been summarized with special emphasis on cycling processes.542It is estimated that some 50--60% of the global S cycle (omitting sea-spray SO:-) is contributed by man’s activities, with -20-50% of SO, emissions to the atmosphere being oxidized to SO:- aerosols.525The bacteriogenic production of H,S in anoxic muds is considered to be the main source of an estimated 100-200 x lo6 tons yr-1 of biogenic S entering the global atmosphere.543From a review of results on global cycling of Hg it is concluded that -30% of current levels of Hg in air and rainwater originate from man’s activities.544 The local and regional cycling of elements has also been examined. Investigations over the past 7 years on cycling of Cd, Pb, and other trace metals in the atmospheric and terrestrial environment, sponsored by the US National Science Foundation, are summarized by W i x ~ o n In . ~one ~ ~ such study in N.W Indiana the atmospheric input and fate of Cd, Cu, Pb, and Zn has been studied in dune, marsh, and floodplain ecosystems.546A water-catchment area (Walker Branch Watershed, Oak Ridge, Tennessee) retained over 82% of Cd, Cu, and Pb inputs, but 57-75% of Cr, Mn, Hg, and Zn inputs from the the relative importance of natural and anthropogenic inputs to the soil is assessed by comparison of enrichment In the Los Angeles basin (area of 4430 km2) some 12 tons Pb day-’ are estimated to be deposited to soil with 6 tons Pb day-’ advected out of the region.437 Accumulation of Pb in street dust and removal by storms contributes 0.4 tons day-’ to coastal waters with further inputs of 1 ton Pb day-’ from sewage, dry deposition, and rainout-wa~hout.~~’ Only 2% of atmospheric Pb deposited to a deciduous forest was removed by stream runoff although -30% of Cd and Zn inputs were lost in this way.549 Local cycling of Hg deposited to soil as inorganic salts is complicated by The re-emission, possibly following formation of methyl Hg and elemental Hg.5507551 migration of Cd in the environment and potential dangers to man of accumulation in air and in soil is reviewed by Hiatt and Disturbance to ecosystems has been ‘Biogeochernistry of Mercury in the Environment’, ed. J. 0. Nriagu, Elsevier, Amsterdam, 1979. ‘Biogeochemistry of Lead in the Environment’, Ecological Cycles, ed. J. 0. Nriagu, Elsevier, Amsterdam, 1978, Vol. IA. 540 ‘Sulphur in the Environment’, Part I, The Atmospheric Cycle, ed. J . 0. Nriagu, Wiley, New York, 1978. 5 4 ’ ‘Zinc in the Environment’, Part 1, Ecological Cycling, ed. J. 0. Nriagu, Wiley, New York, 1980. 542 ‘Environmental Chemistry of the Elements’, H. J . M. Bowen, Academic Press, London, 1979. 543 D. R. Hitchcock, J . Air Pollut. ControlAssoc., 1976, 26, 210. J44 ‘Environmental Health Criteria No. 1, Mercury’, W.H.O. Geneva, 1976. 545 B. G . Wixson, in ‘Environmental Geochemistry and Health’, The Royal Society, London, 1980, p. 179. 546 W. R. Chaney, R. A. Greenkorn. W. W. McFee, G . R. Parker, and J. M. Kelly, in ‘The Environmental Flow of Cadmium and other Trace Metals’, Section 11-1, Rep. GI-35106, Purdue Univ., Indiana, 1975. 547 A. W. Andren, S. E. Lindberg, and L. C. Bate, Environmental Sciences Publ. 728, Oak Ridge Natl. Lab., Tennessee, 1975. 548 A. W. Andren and S. E. Lindberg, Water Air Soil Pollut., 1977,8, 199. 549 R. I. Van Hook, W. F. Harris, and G. S. Henderson, Ambio, 1977,6, 281. 5 5 0 R. D. Rogers, Rep. EPA 600/3-77-007, US Environ. Protection Agency, N. Carolina, 1977. 5 5 1 U. Hogstrom, L. Enger, and I. Svedung, Atmos. Environ., 1979, 13,465. 5 5 2 V. Hiatt and J. E. Huff, Znt. J . Environ. Studies, 1975, 7 , 277. 53n 539

Environmental Chemistry

50

studied by the exposure commitment approach, applied to the migration of Hg553 and Pb.554

6 Removal of Particulates from the Atmosphere The mechanisms and rates of removal of particulates from the atmosphere by dry-deposition processes of sedimentation, impaction and diffusion, and by rainout and washout have received detailed attention. Dry Deposition to Land.-Physical processes associated with dry deposition of particles are discussed by S l i r ~ nwith ~ ~ ~reference to five layers, namely aloft, boundary, canopy, deposition, and edaphic layers. Experimental approaches to measurement of vertical fluxes of pollutants above natural surfaces under field conditions are reviewed,556and theoretical estimates of dry and wet deposition are compared with field and laboratory Factors that influence transport of airborne particles across viscous boundary layers that surround individual leaves and the outer part of the boundary layer in plant canopies are identified by Chamberlain.S5* The viscous sub-layer of the leaf has an important influence on ‘blow-off of deposited particles and larger particles (d > 5 pm) may tend to rebound (‘bounce-off effect);558physiological factors such as stickiness and hairiness of leaves can increase the collection efficiency of particles compared with a smooth, glabrous lamina.559* 560 Combustion-derived aerosols containing heavy metals are a greater potential hazard to grazing animals from ingestion than by the inhalation pathway and the normalized specific concentration factors (NSC) where NCS =

amount of pollutant kg-l dry wt. foliage 3

amount of pollutant deposited

for several metals are 30-60 m-2 days kg-1.558An inverse m-2 day-’ relationship is established between the deposition velocity (V,) of elements, that is related to particle size, and their enrichment factors as shown in Figure 4561 where V,(cm s-’) =

rate of dry deposition, in pg cm-* s-l concentration in air, in pug

A mean Vg of 0.025 cm s-’ was found for a SO:- aerosol with most of the mass in the size range 0.1-1 pm, although occasional larger particles from 1-20 pm diameter showed higher Vgfrom 0.06-2.5 cm s - ’ . ~ ~ ~ P. T. Barry, MARC Tech. Rep. No. 12, Chelsea Coll., Univ. London, 1979. G. B. Wiersma. MARC Tech. Rep. No. 15, Chelsea Coll., Univ. London. 1979. W. G. N. Slinn, in USERDA Symp. Ser. No. 38, NTIS, Springfield. VA, 1976, p. 1. B. B. Hicks and M. L. Wesely, Rep. PB-285-765, NTIS, Springfield, VA. 1978. s57 W. G. N. Slinn, Water A i r Soil Pollut., 1977, 7, 5 13. 5 5 8 A . C . Chamberlain, in ‘Vegetation and the Atmosphere’, ed. J. L. Monteith. Academic Press. New York, 1975, Vol. 1, p. 155. s 5 9 J. B. Wedding, R. W. Carlson, J. J. Stukel. and F. A. Bazzaz, EnL>iron.Sci. Technol., 1975, 9, 15 1. 560 P. Little and R. D. Wiffen, Atmos. Enciron., 1977, I I , 437. P. A. Cawse, AERE Harwell Rep. R9886, H.M.S.O., London. 1981. s62 J. A. Garland, Atmos. Enuiron.. 1978, 12, 349.

ss3

5s4

51

Inorganic Particulate Matter in the Atmosphere

c U

73

\

N ._ -

xSb

m

\, \

E,

-

\

\

C

L

0 c

10 r

x Na

x v

m

x Cr

X

Lc c

x co

C

E -c

X

La

.-0

---_

1 T

L

U CI

o

t.

0

l

'

~

'

0.5

~

'

~

~

~

"

"

~

1.5 Dry deposition velocity, crn s 1

"

'

~

2

t

'

'

2.5

'

Figure 4 Enrichment factors and dry deposition velocities of elements in air particulate at Styrrup, Notts., 1919 (Reproduced by permission from AERE Harwell Report R 9886)

The net daily particle exchange between the atmosphere and natural surfaces has been studied using fast response sensors to record vertical wind speed and particle c ~ n c e n t r a t i o n .At ~ ~ ~night, upward particle fluxes were found from grass, pine forest, and maize, but downward fluxes occurred in part of the day: over snow and wet soil the fluxes were upward at all times.564Dry deposition of particulate Pb to tree leaves in an urban area was measured from the difference in the ratio 210Pb/Pb in air (0.13 d.p.m.* lug-') and Pb of soil origin (0.04 d.p.m. From wind-tunnel tests with 203Pb-labelledexhaust it was found that compared with bare soil, the Vg to grass-covered soil (of non-aggregated aerosol) was increased by 4-fold to 0.14 cm s - ' . ~ ~ O Similar tests are described on the deposition of 212Pb-taggedaerosols to barley, filter paper (ideal smooth surface), and simulated grass.566 Relative contributions of sedimentation, inertial impaction, and eddy diffusion to dry deposition of Cd, Pb, and Zn to Avenafatua indicated impaction as the main mechanism.567The Vgfor particulate Cd, Pb, and Zn to grass agreed well with values derived from micrometeorological methods and indicated deposition

* d.p.m. = disintegrations per minute. M. L. Wesely, B. B. Hicks, W. P. Dannevik. S. Frisella, and R. B. Husar, A m o s . Envirotz., 1977, 11, 561. 564 M. L. Wesely and B. B. Hicks, in 'Proc. 4th Symp. Turbulence, Diffusion and Air Pollution, Reno 1978', Am. Met. SOC.,Boston, 1979, p. 5 10. 565 J. Servant, in USERDA Symp. Ser. No. 38. NTIS. Springfield, VA. 1976. p. 87. 566 A. Ahmed, J. Porstendorfer, and G. Robig. in ref. 41. p. 279. 567 C. 1. Davidson and S. K . Friedlander. J . Geophys. Res.. 1978, 83, 2343.

563

52

Environmental Chemistry

rates of Cd, 2; Pb, 95; and Zn, 160 kg km-' yr-' in the Rhine-Ruhr area:568 however, the V g for Cd and Pb decreased with increasing concentrations of these elements in air and may indicate a saturation mechanism.568For SO,, a V gof 0.9 cm s-' to mixed forest exceeded a V gof -0.1 cm s-' for particulate The multielement composition of dry deposition collected in non-urban regions of the UK has been reported together with data on dry-deposition velocities of elements obtained by simultaneous measurement of air concentrations.222 Deposit gauges show that in urban regions the undissolved deposit is frequently from 200-600 mg m-, day-' or an order of magnitude more than in rural areas of the UK.570In New York City, the average dustfall of metals is Cd 0.0067, Cu 0.033, Fe 5.7. Ni 0.13, Pb 0.83, V 0.17, and Zn 0.83 mg m-' Removal by dry deposition of emissions from a coal-fired power station is estimated as -10% for particles with V g = 1 cm s-I, deposited in a 22.5" sector within 50 km, but -25% for larger particles with Vg= 3 cm

Precipitation Scavenging.-A detailed summary of both theoretical and field studies on in-cloud ('rainout') and below-cloud ('washout') scavenging of aerosols by rain and snow was presented at the 1974 Illinois Conference.573Measured washout factors for some 20 elements, defined as ratio of concentration in surface level precipitation average concentration in surface level air

9

are listed,574and the tendency for these factors to increase with particle size is discussed by gat^.^^^ Washout ratios of 300-1000 are expected for SO:- aerosols in situations not influenced by large SO:- inputs from s e a - s ~ r a y . ~The ~ , relative importance of direct SO:- scavenging by precipitation and removal following oxidation of SO, has been examined.576 Experimentally determined washout coefficients (fractional amount of pollutant aerosol removed per unit time by precipitation) of particles from 0.01-1 ,urn diameter ranged from 2 x to 1 x s-I, or at least an order of magnitude above estimates derived from theoretical considerations, and the influence of coagulation and condensation growth of particles on this difference is inferred.577A relatively large scavenging collection efficiency (SCE, or collision efficiency x retention efficiency) of precipitation is observed for particles from 0.0 1-0.05 pm diameter (SCE 0.8), and is attributed to an increasing hygroscopic component with D. H. Schwela, Ecotoxicol. Environ. Safety, 1'979, 3. 174. J. S. Eaton, G . E. Likens, and F. H. Bormann, Tellus. 1978. 30. 546. 570 'The Investigation of Air Pollution; Deposit Gauges', Rep. Warren Spring Laboratory, Dept. of Industry, London, 1978. 5 7 1 M. T. Kleinman. T. J . Kneip, D. M . Bernstein. and M. Eisenbud. in USERDA Symp. Ser. No. 42.. NTIS, Springfield, VA. 1977, p. 144. s 7 2 L. E. Wangen, in Rep. LA 8023-PR, LASL Health Division, 1979, p. 159. 5 7 3 'Precipitation Scavenging (1974)', USERDA Symp. Ser. No. 41.. NTIS, Springfield, VA, 1977. 574 W. G. N. Slinn, L. Hasse, B. B. Hicks, A. W. Hogan, D. Lal. P. S. Liss, K. 0. Munnich. G . A. Sehmel, and 0. Vittori, Atmos. Eni,iron., 1978. 12, 2055. 575 D. F. Gatz. Water Air Soil Pollut., 1975, 5 , 239. 5 7 6 J. M. Hales, Armos. Eniiiron., 1978, 12, 389. 5 7 7 H. M. Davenport and L. K. Peters, Atrnos. Enuiron., 1978, 12, 997. 568

569

Inorganic Particulate Matter in the Atmosphere

53

decreasing size in this range.578With particles from 1-4 pm diameter, SCE again increases with size, removal being mainly by inertial impaction with Models have been developed to compute the effects of humidity and electric charge on precipitation scavenging. 580 A high collection efficiency for below-cloud scavenging of aerosols by snow crystals has been confirmed by direct observation of attached particles from the ambient atmosphere, mainly from 0.5-1.5 pm diameter.581The primary capture mechanism by snow appears to be simple interception.582In large hailstones from an arid region, concentrations of large particles (d = 40-60 pm) were typically 104- lo6 kg-I of ice.583In snow samples from Antarctica, 60% of the crystal nuclei contained clay minerals such as illite and kaolinite and 20% contained NaC1.584 Analysis of snow has been used to indicate current industrial p o l l ~ t i o n , ~and ~~-~~~ alkaline snowfalls have occurred by scavenging of Ca and Mg carbonates in dust emissions from cement industries.589Snow profiles from Antarctica, deposited from 1914-1974, have revealed comparable concentrations of Ag, Cd, Cu, Pb, and Zn at all depths, possibly from a natural origin such as volcanic or maritime-derived a e r o s 0 1 s . ~A ~ ~similar , ~ ~ ~ feature in pre-1900 ice cores from Greenland has provided analytical data that suggests an input by aerosol deposition following crustal outgassing and volcanic activity rather than continental dust or maritime 593

Total (Wet + Dry) Deposition.-The input of elements from the atmosphere to the ground by wet and dry deposition is of particular interest to agriculturalists and ecologists to establish nutritional or toxic effects and cycling of elements in terrestrial and aquatic environments. The accumulation of such deposition in soil has indicated the extent of industrial pollution. From analysis of rainwater and dry deposition, the total deposition of 40 elements was recorded each month at rural locations in the UK from 19721975.72The solubility of elements in this deposition was high for As, Cu, Ni, Pb, Se, and Zn, but lower for elements mainly associated with larger particles, namely Al, Eu, Fe, Sc, Sm, and Ti, which would be less available to biological Analysis of the soluble fraction was made from 1967-1972 at rural sites in

L. F. Radke, M. W. Eltgroth, and P. V. Hobbs, in ‘Proc. Am. Met. SOC.Conf. Cloud Physics and Atrnos. Electricity’, Washington, 1978, p. 44. 579 S. N. Grover, H. R. Pruppacher, and A. E. Hamielec, J . Atmos. Sci., 1977, 34, 1655. 5 8 0 P. K. Wang, S. N. Grover, and H. R. Pruppacher,J. Atmos. Sci., 1978, 35, 1735. 5 8 ’ C. Magono, T. Endoh, F. Veno, S. Kubota, and M. Itasaka, Tellus, 1979, 31, 102. 5 n 2 E. 0. Knutson, S. K. Sood, and J. D. Stockham, Atmos. Enuiron., 1976, 10, 395. 583 J. Rosinski, K. A. Browning, G. Langer, and C. T. Nagamoto, J . Atmos. Sci., 1976, 33, 530. *84 M. Kurnai, J . A m o s . Sci., 1976, 33, 833. 5 8 5 E. J. Forland and Y. T. Gjessing, Atmos. Environ., 1975,9, 339. m A. W. Struempler, Atmos. Environ., 1976, 10, 33. 5n7 P. J. Galvin and J. A. Cline, Atmos. Enuiron., 1978, 12, 1163. W. G . Franzin, G. A. McFarlane, and A. Lutz, Environ. Sci. Technol., 1979, 13, 15 13. 589 R. J . Allan and I. R. Jonasson, A m o s . Enuiron., 1978, 12, 1169. C. Boutron and C . Lorius, Nature (London), 1979,277,55 1. s 9 1 C. Boutron, Nature (London), 1980, 284, 575. 59*M. M. Herron, C . C. Langway, jun., H. V. Weiss, and J . H. Cragin, Geochim. Cosmochim Acta., I977,41, 9 15. 593 H. V. Weiss, M. M. Herron and C. C. Langway, jun., Nature (London), 1978, 274, 353.

57n

54

Environmental Chemistry

England where weights of insoluble deposit ranged from 20-250 kg ha-' yr-I, being directly related to proximity of industry.5y4 In the Nigerian savanna, total deposition of Br, Ca, Co, Cu, Fe, Ni, Sc, Sm, Th, V, Zn, NH;, NO;, and SO:- showed an order of magnitude increase in the rainy season (April to October) compared with the dry season.s95It was noted that enrichment factors (normalized to Sc in average soil) for As, Ni, Pb, Sb, Se, and V in this deposition in Nigeria were generally an order of magnitude below those recorded at Chilton, Oxfordshire U K , reflecting industrial influences at high latitudes in the N. hemisphere.595In Trinidad, major anions and cations essential to plants have been measured in rainfall and deposited Analysis of rainwater samples from Norway has shown similar regional deposition patterns for As, Cd, Pb, Sb, Se, and V, which is mainly attributed to the transport of aerosols from industrial regions of Europe, although for Se a contribution from maritime-derived aerosols is indicated.s97A comparison of rural and urban deposition rates of some metals reported in the literature is made in Table 5. Much attention has been given to the acidity of precipitation and deposition of SO:-, particularly in Canada and Scandinavia, to investigate the disturbance of soil, forest, and aquatic ecosystems.600-604In Ontario, episodes of acid precipitation gave pH 3.0 in rainwater605 and acidification of a lake was related to scavenging of H,SO, aerosols, probably derived from local smelting industry.606 In Norway, deposition of non-maritime SO:- is heaviest in the south (4 g SO:- rn-, yr-') and precipitation has an average pH of 4.3; about 75% of the SO:- is deposited as wet d e p o ~ i t i o n . ~In~ ' the rural E. Midlands of the UK it is reported that rainwater acidity decreases from west to east, away from major combustion sources of SO,.6o8 In W. Germany, deposition of S from the atmosphere to spruce forest (80-86 kg ha-' yr-') exceeded accumulations in beech woodland (47-51 kg ha-' yr-') and on bare soil (23 kg ha-' ~ r - ' ) ,indicating ~ ~ ~ more efficient interception of aerosols by the canopy.609 Measurement of the true contribution of rainwater to total (dry + wet) deposition was made over one year at a rural site in S. England (Chilton, O ~ f o r d s h i r e ) .The ~~ rain collection funnel was covered during dry weather by an automatically operated screen so that this rainwater sample could be compared with a permanently exposed collector: over 76% of the total deposition of Co, Cu, Pb, Se, and Zn was G . A. Wadsworth and J . Webber, in ref. 72. p. 47. F. Beavington and P. A. Cawse. Sci. Total En~iron..1979. 13. 263. s96 R. C. Dalal, Water Resources Res.. 1979. 15, 1217. "' A. Semb, Res. Rep. F R 13/78, SNSF Project. Aas. Norway. 1978. P. A. Cawse, A E R E Harwell Rep. G1343, Didcot, Oxon.. 1980. 599 J . Ruppert, Waier Air Soil Pollui.. 1975. 4. 447. 6oo E. Gorham, Water Air Soil Pollut.. 1976, 6. 457. '"C. L. Schofield, Ambio, 1976, 5, 228. 602 W. W. McFee, J. M.Kelly. and R. H. Beck. Water Air Soil Pollui.. 1977, 7,401. '03 J . 0. Reuss. Water Air Soil Pollut., 1977, 7. 46 1. 6"4 'Proc. N A T O Conf. Effects Acid Precipitation on Terrestrial Ecosystems', ed. T. C. Hutchinson and M. Havas, Plenum Press, New York, 1980. '"'P. J Dillon, D. S. Jeffries, W. Snyder, R. Reid, N. D. Yan. D. Evans, J. Moss, and W . A. Scheider. J . Fisheries Hes. Bd. Canada, 1978, 35, 809. 'Ob R. J . Beamish and J . C . Van Loon, J . Fisheries Res. Bd. Canada, 1977. 34, 649. '"'F. H. Braekke, Res. Rep. FR6/76, SNSF Project, Aas, Norway, 1976. 60R A. Martin and F. R. Barber, A tmos. Enriron.. 19 78. 12. I48 1. 6oy R. Mayer and B. Ulrich, Atmos. Enuiron., 1978, 12, 375.

594

s93

'''

1.5

0.02 0.14 9.5 0.82 -

502

x 0.1 = kg hectare-'.

1.2 28 2.8 0.6 1 4.9 643

(0.5

Chilton, Oxon., Background station, UK12 Denmark 3 5

* ,pg cm-'

Rainfall, mm yr-'

Zn

v

Fe Pb

cu

Cd

Element

Rural

3.7 -

-

Membach, A rdennes, Belgium343 0.0 15 84 1.8 <0.2 6.7 155
Northern Nigeria 595

Table 5 Total deposition of metals to rural and urban areas (pug cm-* yr-')*

10 1160

3.6 135 6.2 0.8 1

S wansea, S. Wales 220

-

91 740

Walsall ( S .W.) W. Midlands, UK598 1.2 147 48 3.5

Urban

4.7 6 70

-

0.039 1.1 96 2.3

Gottingen, W. Germany599

2

3u

5

'8

3

%

56

Environmental Chemistry

contributed by rainwater, but dry deposition provided >85% of Al, Sc, and Fe and 15% of Ca, Mn, and V.72 The Air-Sea Interface.-The downward flux and mechanisms by which atmospheric particles are deposited to the ocean are difficult to establish, being complicated by sea-air transfer processes that cause particulate matter to be ejected in bubble bursting and as spray formed during intense ocean turbulence. Many particulate metals (Al, Cd, Cr, Cu, Fe, Mn, Pb, and V) are known to be enriched in the sea surface microlayer compared to bulk seawater, either from transport to the surface by bubble flotation or by deposition of atmospheric trace elements.371Where atmospheric input fluxes are sought, the re-cycling of sea-salt particles and associated metals may distort the true net flux from air to sea. Recommendations are made for modelling the transfer of metals to oceans by wet and dry deposition,610and development of a multilayer model to describe transfer of air particulates past the air-sea interface is reviewed.574Dry deposition of particles to ocean surface films can be followed using radionuclides from nuclear weapon fallout as tracers, but complexities in mass-transfer rates arise from the presence of monolayer or multilayer films (organic and/or inorganic) and variable wind speeds that affect the shear of such films.611 The flux of metals from the atmosphere to the N. Atlantic Ocean has been estimated.610Atmospheric inputs to the North Sea of Cu and Pb were estimated as nearly 3 times the amounts discharged through the River Rhine, while for Mn, Ni, and Zn the relative inputs were almost The transport of Pb to the oceans and its subsequent fate has been examined:613industrial inputs of Pb to the world oceans are estimated as 4 x lo4tons yr-’ from the atmosphere and some 6 x lo4 tons yr-l by rivers and sewers, or about 40 times greater than the ‘neolithic rate’ of The flux of V from air to sea between latitudes 30°-600N is -2 x lo6 kg yr-l, or about 10% of the anthropogenic emissions from continental regions.614 In oceanic regions remote from industry such as the Gulf of Alaska, the input of Fe from the atmosphere is apparently an important source of Fe that is available to marine organism^.^'^.^^^ Interest in atmospheric inputs of elements to the Great Lakes system with respect to nutrient budget, acidity, and accumulation of heavy m e t a W 7 has led to specific modelling estimates of the dry deposition, allowing for local meteorological features,61Eand an appraisal of experimental appro ache^.^'^ Gatz 5 7 5 estimated that element inputs to Lake Michigan from wet and dry deposition are approximately ‘The Tropospheric Transport of Pollutants and other Substances to the Oceans’, US Natl. Acad. Sci./Natl. Res. Council, Washington DC, 1978. 6 1 1 G. A. Sehmel, in Rep. Batelle Pacific N.W. Labs., BNWL-SA-5597, Richland, WA, 1975, p. 1. 612 R. S. Carnbray, D. F. Jefferies, and G. Topping, Mar. Sci. Commun., 1979, 5, 175. 6 1 3 C. Patterson, D. Settle, B. Schaule, and M . Burnett, in ref. 373, p. 23. 6 1 4 R. A. Duce and G. L. Hoffman, Afmos. Enuiron., 1976, 10,989. 6 1 s W. C. Weimer and J . C . Langford, Armos. Environ., 1978, 12, 1201. 6 1 6 W. C. Weimer, J . C. Langford, and C. E. Jenkins, Rep. Batelle Pacific N.W. Labs., PNL-2280, UC 1 I , Richland, WA, 1978. 617 F. C. Elder, R. A. Fleming, and P. J Denison, in ‘Proc. 2nd Conf. Am. Met. SOC. on Hydrometeorology’, Toronto, 1977, p. 156. 6 1 8 H. Sievering, in ref. 564, p. 5 18. 61y J. W. Winchester, J . Great Lakes Res., 1976, Vol. 2 , Suppl. 1. 610

Inorganic Particulate Matter in the Atmosphere

57

equal; for Fe and Pb the atmospheric inputs are about double the soluble inputs of these elements by streams. In the southern basin of Lake Michigan, surface enrichment of Cd, Cu, Pb, and Zn occurred mainly in the particulate phase being mainly associated with fly ash, other particles of anthropogenic origin and diatom fragments.620In fact, a flux of 106--107 fly ash particles cm-2 yr-’ is estimated.621 With respect to phosphorus it is reported that 18% of the total P budget of Lake Michigan is probably contributed by atmospheric deposition.622The deposition flux to Lake Huron averaged 1.4 ,ug P cm-2 day-’, with 29% of the P on particles (0.5 pm diameter.623 The dry and wet deposition of available P (i.e. water and acid-soluble P) was approximately equal and comprised 44% of total P in the 7 Effects of Airborne and Deposited Particulates

The effects of air particulates may be considered by reference to targets;625damage to the target or receptor organism may be acute (short exposures to high concentrations of pollutants) or chronic (exposures to lower concentrations over longer periods). Effects on biological targets may be expressed directly by physical or chemical mechanisms, or indirectly by alteration of the habitat.625The possibility of synergistic action by pollutants must also be considered.625Effects on human health, animals, plants, and weather have been reviewed.626

Hazard to Man.-Inorganic particulates that are inhaled into the respiratory tract are deposited mainly by impaction, sedimentation, interception, and d i f f ~ s i o n . ~ ~ ~ - ~ ~ The coarser fraction of the inhaled particles (d > 5 pm) are deposited in the nasal passages, nasopharynx, oral passages, and larynx. The next main region of deposition is the tracheobronchial zone and finally, for inhaled particles with aerodynamic diameters from 0.1-2 pm, deposition occurs mainly in the alveolar region of the lung beyond the terminal bronchioles. For subjects breathing particles of 0.1-4 pm diameter via the nose, alveolar deposition is -20%.627The density, shape and solubility as well as size of inhaled particles is of primary importance in deposition, retention, and clearance from the respiratory tract: tissue and cellular reactions to the particulates, including problems of asbestosis and silicosis are

A. W. Elzerman, D. E. Armstrong, and A. W. Andren, Entiiron. Sci. Technol., 1979, 13, 720. J. J. Alberts, J. Burger, S. Kalhorn, C. Seils, and T. Tisue, in ref. 148, p. 379. 622 T. J. Murphy and P. V. Doskey, Rep. EPA-600/3-005, US Environ. Protection Agency, Duluth, MN, 620

621

1975. R. Delumyea and R. L. Petel, Atmos. Enuiron., 1979, 13, 287. 624 R. Delumyea and R. L. Petel, Water Air Soil Pollur., 1978, 10, 187. 6 2 5 M. W. Holdgate, Philos. Trans. R. Soc. London, Ser. A , 1979, 290, 59 I . 626 ‘Air Pollution’, Vol. 2, 3rd Edn., ‘The Effects of Air Pollution‘, ed. A. C. Stern, Academic Press, New York, 1977. M. Lippmann and B. Altshuler, in ‘Proc. 20th Ann. O H O L O Biol. Conf. Air Pollut. Lung’, ed. E F. Aharonson and A. Ben-David, Wiley, New York, 1975, p. 25. R. Hounam and A. Morgan, in ‘Lung Biology in Health and Disease’, Vol. 5, ‘Respiratory Defence Mechanisms’, Part I , ed. J . D. Brain, D. F. Proctor, and L. M. Reid, Marcel Dekker, New York, 1 9 7 7 , ~ 125. . 62y M. Lippmann, in Handbook of Physiology, Section 9. ed. H. L. Falk, Williams and Wilkins, Baltimore, 1977, Ch. 14, p. 213.

623

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recently r e v i e ~ e d . ~ ~Inhalation O - ~ ~ ~ of metallic aerosols may damage arterial, renal, and nervous ~ y ~ t e m ~ . ~ ~ ~ - ~ ~ ~ The haemolytic properties of elements in particulate form followed the order Si > Ni > Co > Cr > Fe > Mo > Ti > Cd > Zn and an initial direct interaction between the red cell membrane and particle surface was indicated, with the additional possibility of toxicity from dissolved At the cellular level, excessive concentrations of heavy metals can inhibit or inactivate enzyme systems.637 Table 6 Research on toxicity of dusts to man and animals Type of dust or major element contained A1 (+Zr) Be Cd co F Fe Mn Ni NO3 Pb

Si

Ta Zn Asbestos dusts including amphiboles and serpentine (chrysotile) forms

A uthorslR eferences Styles and Wilson63x Zorn et al.639 Asvadi and Hayes;64nBus et Oberg;h42 G e ~ r g i a d iPopov ; ~ ~ ~ et ~ 1 . ' ~ ~ Kinkead et ~ 1 . ' ~ ~ Nettesheim et al.647 Bergstrom and R ~ l a n d e rCoulston ; ~ ~ ~ and Griffin;649 Singh et al.650 Camner et Bell and Hackney652 Bouley et al.;653Griffin el al.;654Hapke and Abe1;655 Morgan and H o l m e ~ Schultz ; ~ ~ ~ and Skerfving'jS7 Adamis and ti ma^-;^^' Le Bouffant et al.;"' Keusch and Ruettner;66nSingh et a1.66' Bell et Bruch et al.;663Sackner et al.;664 Schlesinger et aL6'j5 Nemetschek-Gander et a1.666 Rosenberger and GruendeP7 Leong et a1.;668Morgan et al.;h699670 Rahman et al.;671 Singh et a1.;6'2 Wagner;"7' Wehner el al."'

J. S. Harrington and A. C. Allison, in ref. 629, p. 263. 'Inhaled Particles Vol. 4', Part 2, ed. W. H. Walton and B. McGovern, Pergamon Press, Oxford, 1977. 632 'Airborne Particles', Natl. Res. Council USA, Univ. Park Press, Baltimore, 1979. 633 'Environmental Hazards of Metals'. I.T. Brakhnova, Consultants Bur., New York, 1976. '"J. Calop, P. lsoard, and R. Fontanges, Bull. Med. Leg. Urgence Med.. Cenf. Anti-Poisons. 1977, 20, 404. ""Handbook on the Toxicology of Metals', ed. L. Friberg, G . F. Nordberg, and V. B. Vouk, Elsevier/N. Holland Biomedical Press, Amsterdam, 1979. 636 T. Rae, J . Pafhol., 1978, 125, 8 I . 6 1 7 G. L. Eichorn, in 'Ecological Toxicology Research', ed. A. D. Mclntyre and C. F. Mills. Plenum Press, New York, 1976, p. 123. 63M J . A. Styles and J. Wilson,Ann. Occup. Hjjg., 1976, 19, 63. 639 H. Zorn, T. Stiefel, and H. Diem. Zenrralbl. Arbeitsmed. Arbeitsschutz Proph.d., 1977, 27. 83. 640 S. Asvadi and J. A. Hayes, A m . J . Pathol., 1978. 90. 89. 64 I J. S. Bus, A. Vinegar, and S. M. Brooks, A m . Reu. Respir. Dis.. 1978, 118. 513. b42 S. G. Oberg, Diss. Abstr. In(. B . , 1977, 37, 4030. 64' R. M. Winston, Br. Med. J.. 1975, May 15, 401. 644 G. A. Georgiadi, Zh. Ushn. Nos. Gorl. Bolezn., 1978, No. 1.63. L. N. Popov. T. A. Kochetkova. M. I. Gusev, N. A. Markina, E. V. Flfimova. and M. A. Timonov. Gig. Sanit., 1977, No. 6 , 12. b4b E. R. Kinkead, K. 1. Darmer, jun.. L. C. DiPasquale, and C. C. Haun. Rep. AMRL-TR, Aerospace Med. Res. Lab., Univ. California, Irvine, 1975. 6 4 7 P. Nettesheim. D. A. Creasia. and T. J . Mitchell, J . N a f l . Cancer Inst.. 1975. 55. 159. 63"

Inorganic Particulate Matter in the Atmosphere

59

Examples of recent research into biochemical and toxicological properties to man and animals of inhaled dusts are listed in Table 6. Cytotoxicity of inhaled Pb aerosols towards alveolar macrophages, which provide defence against respiratory infection, has been d e m ~ n s t r a t e d . Other ~ ~ ~ , ~workers ~~ have applied methanol extracts of air particulates from urban areas to test bacteria, to show mutagenic activity from organic pollutants associated with inorganic The high incidence of respiratory disease in many industrial areas of the UK especially prior to control legislation in 1960 is confirmed by data from other polluted cities of the world;680however, recent improvements in health cannot yet be attributed to a lower concentration of any specific pollutant.680 The ‘Environmental Health Criteria Programme’ organized by the W.H.O. in 1973 was designed to study the relationship between exposure to pollutants and health and to identify new or potential pollutants. A series of reports are now available that discuss Hg,544Pb,681 and sulphur oxide^.^ Health effects of R. Bergstrom and R. Rylander, in ref. 152, p. 178. F. Coulston and T. Griffin, Rep. PB-268643, NTIS, Springfield, VA, 1977. ‘”J. Singh, J. L. Kaw, and S. H. Zaidi, Toxicology, 1977,8, 177. 651 P. Camner, A. Johansson, and M. Lundborg, Enuiron. Res., 1978, 16,226. 6J2 K. A. Bell and J. D. Hackney, Rep. PB-257745, NTIS, Springfield, VA, 1976. 653 G. Bouley, A. Dubreuil, F. Arsac, and C. Boudene, in ref. 4 1, p. 127. 654 T. B. Griffin, F. Coulston, H. Wills, and J. C . Russell, Environ. Qual. S a j Suppl., 1975, 2, 202. 655 H. J. Hapke and J. Abel, Dtsch. Tieraerztl. Wochenschr., 1978, 35, 288. ‘S6 A. Morgan and A. Holmes, Enuiron. Res., 1978, 15,44. 657 A. Schutz and S. Skerfving, Scand. J . Work, Environ. Health, 1976, 2, 176. 658 Z. Adamis and M. Timar, Br. J. Exp. Pathol., 1978, 59,411. 6 5 9 Le Bouffant, H. Daniel, J . C. Martin, and S. Bruyere, C. R . Hebd. Seances Acad. Sci., Ser. D , 1977, 285,599. 66u F. Keusch and J. R. Ruettner, Exp. Cell Biol., 1978, 46, 257. J. Singh, P. N. Viswanathan and S. H. Zaidi, in ‘Proc. 1st Int. Symp. Environ. Pollut. Human Health, 1977, p. 3 14. K . A. Bell, W. S. Linn, and J . D. Hackney, Rep. PB-275789, NTIS, Springfield, VA, 1978. 663 J. Bruch, G . H. M. Krause, and H. D. Rogge, VDI Bericht. 1978, 314, 159. 664M. A. Sackner, D. Ford, R. Fernandez, J. Cipley, D. Perez, M. Kwoka, M. Reinhart, E. D. Michaelson, R. Schreck, and A. Wanner, Am. Rev. Respir. Dis., 1978, 118,497. h65 R. B. Schlesinger, M. Lippmann, and R. E. Albert, J . Am. Ind. Hyg. Assoc., 1978, 39, 275. 666 H. Nemetschek-Gansler, Th. Nemetschek, H. Polley, H. Wesch, H. D. Renovanz, and H. Franz, Pneumonologie, 1975, 152, 299. G. Rosenberger and H. D. Gruender, in ‘Proc. 20th World Vet. Congr., Vol. 3’. 1975, 2059. 668 B. K. J. Leong, R. J. Kociba, H. C. Pernell, R. W. Lisowe, and L. W. Rampy, J. Toxicol. Environ. Health., 1978, 4,645. 669 A. Morgan, P. Davies, J. C. Wagner, G. Berry, and A. Holmes. Br. J . Exp. Pathol., 1977, 58,465. 670 A. Morgan, A. Holmes, and R. J. Talbot, Ann. Occup. Hyg., 1977, 20. 39. 6 7 1 Q. Rahman, M. U. Beg, P. N. Viswanathan, and S. H. Zaidi, Scand. J . Work, Enuiron. Health, 1975, 1, 50. 6 7 2 J . Singh, M. U. Beg, J. L. Kaw, P. N. Viswanathan, and S. H. Zaidi, Acra Pharmacol. Toxicol., 1976, 39,77. h73 J . C. Wagner, Ann. Anaf. Pathol., 1976, 21, 21 1. 674 A. P. Wehner, G. E. Dagle, W. C. Cannon, and R. L. Buschbom, Environ. Res., 1978, 17,367. 675 H. W. Schlipkoter, G. H. M. Krause, R. Stiller-Winkler, and A. Brockhaus, Zhl. Bakt. Hyg. I Aht. Orig., 1977, B165, 251. 676 C. Aranyi, F. J. Miller, S. Andres. R. Ehrlich, J. Fenters, D. E. Gardner, and M. D. Waters, Environ. Res., 1979, 20, 14. 6 7 7 H. Tokiwa, K. Morita, H. Takeyoshi, K . Takahashi, and Y. Ohnishi, Mutation Res., 1977. 48, 237. 67x W. Dehnen, N. Pitz, and R. Tomingas, Cancer Letf., 1977,4, 5 . 679 R. Talcot and E. Wei, J. Natl. Cancer Inst.. 1977, 58,449. J. McK. Ellison and R. E. Waller, Enuiron. Res., 1978, 16, 302. ‘Environmental Health Criteria No. 3, Lead’. W.H.O. Geneva, 1977. m2 ‘Environmental Health Criteria No. 5 , Nitrates’, W.H.O. Geneva, 1977. 648 649

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As, Cd, Cr, Hg, Ni, and Pb in air, food, and water were reviewed at an E.E.C. Symposium,683and in a special report on Cd684it is estimated that 13--19% of inhaled Cd is absorbed by adults. The inhalation risks from Cd, Hg, and Pb are also examined in a consensus report of specialists.685Separate reviews of environmental hazards are available for Ag,686Be,687Cd,688Cr,689In,690and Tl.691Potential hazards to health of man, animals, and plants by trace-metal emissions from combustion of coal have been discussed by several a ~ t h o r s . ~ ~ ~ - ~ ~ ’ Particulate Pb in the atmosphere may enter man by direct inhalation or following contamination of Inhalation by adults of air containing 1 pg Pb m-3 can lead to accumulation of 1.2 pg Pb/100 ml of blood,697while oral intake of 100 ,ug Pb would contribute -6-18 pg Pb/100 m1;68’ normal diets give an intake of 200-300 pg Pb day-1.681A recent review has been made of factors affecting the deposition of Pb aerosols in the human lung, the blood Pb levels and eventual It is found that dusts from urban roads storage in the body, mainly in bone may contain up to 3600 pg Pb g-’ and 10 pg Cd g-’ and represent a potential health hazard to children in particular.699Much research into the uptake an& metabolism of Pb by man and animals has been made using specific Pb isotope ratios as marker^."^*^^^ In one such experiment a decrease in ratios of natural 206Pb/204Pb and 206Pb/207Pb in blood of adults in winter was attributed to a release of skeletal Pb deposits that are of different geological age, having lower isotope ratios than Pb in current air and diet.’O1 The carcinogenic and fibrogenic effects of fibrous dusts originating from asbestos, building, and textile (glass fibre) industries have been demonstrated in animal and Pott 703 advocates inclusion of other inhalable fibres in ‘Trace Metals, Exposure and Effects’, C E C Rep. EUR6389, E.E.C. Luxembourg, 1979. ‘Criteria (Dose/Effect Relationships) for Cadmium’, C E C Rep. EUR5697, E.E.C. Luxembourg, 1978. ‘Effects and Dose-Response Relationships for Toxic Metals’, ed. G . F. Nordberg, Elsevier, Amsterdam, 1976. ‘Trace Metals in the Environment, Vol. 2, Silver’, I. C . Smith and B. L. Carson, Ann Arbor Press, MI, 1977. 6 R 7 Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 6, Beryllium, USEPA, 1978. Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 4, Cadmium, USEPA, 1978. ‘Kg Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 3, Chromium, USEPA, 1978. 690 ‘Trace Metals in the Environment Vol. 5 , Indium’, 1. C . Smith and B. L. Carson, Ann Arbor Press, MI, 1978. 6 9 ’ ‘Trace Metals in the Environment, Vol. 1, Thallium’, I. C. Smith and B. L. Carson, Ann Arbor Press, MI, 1977. D. L. Davidson and E. M. Cause, in ‘Proc. Ann. Conf. Microbeam Anal. Soc.’, 1978, 13, Paper 59a. 693 E. Piperno, in ref. 400, p. 192. 694‘Effects of Trace Contaminants from Coal Combustion’, ed. R. I. Van Hook and W. D. Shults, USERDA Rep. 77-64, NTIS, Springfield, VA, 1977. 69s A. Robson, Rep. PL-GS/E/5/79, CEGB, London, 1979. 696 ‘Lead and Health’, Rep. D.H.S.S. Working Party on Lead in the Environment, H.M.S.O., London, 1980. 697 A. C . Chamberlain, W. S. Clough, M. J . Heard, D. Newton, A. N. B. Stott, and A. C. Wells, Proc. R . SOC.London, Ser. B., 1975, 192. 77. A. C. Chamberlain, M. J. Heard, P. Little, D. Newton, A. C. Wells, and R. D. Wiffen, A E R E Harwell Rep. R9198,H.M.S.O., London. 1978. R. M. Harrison, Sci.Total Enciron.. 1979, 11, 89. R. B. Holtzrnan, in ref. 539, p. 37. W. 1. Manton, Arch. Environ. Hlth., 1977, 32, 149. ’ 0 2 H. W. Schlipkoter and K. H. Friedrichs, Klima Kaelte Ing.. 1975, 3, 359. ’03 F. Pott, Staub. Reinhalt. Luji, 1978, 38,486. h83

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addition to asbestos when evaluating carcinogenic potency. Relationships between exposure to asbestos fibres and subsequent development of pulmonary disease are discussed in a recent v01ume.l~~ A bibliography of 1425 references is now available on asbestos in the environment, covering physico-chemical properties and biological In cities, 2000-6000 fibres m-3 are reported, increasing to 11 000 fibres mP3 near an asbestos factory.702In a survey of 49 US cities, chrysotile asbestos fibres were mainly in the range 1-5 ng mP3, but attained 30 ng mP3near industrial users. 705 The accumulation in soil of inorganic particulate pollutants deposited from the atmosphere has been used to examine the severity and dispersion of industrial p011ution,~~~-~~* and damage to amenity f o r e s t ~ ,711 ~ 'and ~ ~ crops. 175,708 Contamination of crops by direct deposition of metals from the atmosphere or by uptake of metals from polluted soil may be hazardous to man712,713 and grazing At 10 m from a motonvay, soil contained 1200 pg Pb g-l, but since only 10% of Pb emitted from exhausts is deposited locally, contamination of rural areas is expected;716such depositions are reported to contribute >90% of total Pb in grass in rural Denmark.717In a forest ecosystem, Cd, Cu, Pb, and Zn deposited in dusts from a lead smelter retarded the biological decomposition of litter and humus.71*

-

Air-quality Indices and Standards for Particulate Pollutants.-The abatement and control of air pollution by technical and legislative procedures is now an established part of urban and national planning, to achieve short- and long-term goals for levels of particulates in the a t m o ~ p h e r e .In ~ ~the~ UK * ~ ~a ~system of control by the 'Best Practicable Means' approach has evolved since the first Alkali Act in 1863; thus 'Presumptive Limits' are set by the Health and Safety Executive and may be varied 722 In the US, the to meet special operating conditions at individual '04

J. H. Tucker, P. M. Cook, G. L. Phipps, G. N. Stokes, and P. H. Lima, Rep. EPA/600/3-78/066, US Environ. Protection Agency, N. Carolina, 1978.

705 L. Bruckman and R. A. Rubino, J . Air Pollut. ControlAssoc., 1978, 28, 1221. lo6J. H. Horton, R. S . Dorsett and R. E. Cooper, Rep. DP1475, Savannah River Lab., Aiken, S. Carolina, 1977. '01 V. Masek, Staub. Reinhalt. Luft, 1978, 38,493. ' 0 8 'Trace Element Contamination of the Environment', D. Purves, Elsevier, Amsterdam, 1977. ' 0 9 L. Lerman and E. F. Darley, in 'Responses of Plants to Air Pollution', ed. J. B. Mudd and T. T. Kozlowski, Academic Press, New York, 1975, p. 141. 'lo D. Auclair, Ann. Sci. Forest., 1977, 34,47. 7 1 1 M. Swieboda, Acta SOC. Bot. Pol., 1976, 45, 17. 7 1 2 F. Beavington,Environ. Pollut., 1979, 9, 21 1. 7 1 3 R. Guderian, G. H. M. Krause, and H. Kaiser, Schriftenr. Landesanst. Immisionsschutz Landes Nordrhein- Westfalen, 1977, 40, 23. 714 C. R. Dorn, J. 0. Pierce, G . R. Chase, and P. E. Phillips, Environ. Res., 1975, 9, 159. 'I5 G. Rosenberger, H. D. Griinder, and G. Crossman, Dtsch. Tierartzl. Wochenschr., 1976, 83,478. 716 G. L. Wheeler and G. L. Rolfe, Environ. Pollut., 1979, 18, 265. 7 1 7 J. C. Tjell, M. F. Hovmand, and H. Mossbaek, Nature (London), 1979,280,425. D. R. Jackson and A. P. Watson, J . Environ. Qual., 1977,6, 33 1. 'I9'Manual on Air Quality Management', ed. M. J. Suess and S. R. Craxford, W.H.O. Reg. Publ. I, W.H.O., Copenhagen, 1976. 720 'The Pollution Control Policy of The European Communities', S. P. Johnson, Graham and Trotman, London, 1979. 7 2 1 F. E. Ireland and D. J. Bryce, Philos. Trans. R . SOC.London, Ser. A , 1979,290,625. 122 E. Briggs, in 'Eurochem. Conf. Chem. Engng. in Hostile World,' Birmingham, England, 1977, Paper 6-28- 1.

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Environmental Protection Agency (EPA) has set national ambient air-quality standards (NAAQS) to protect public health against pollution by Pb, sulphur oxides, and total suspended particulates, in addition to emission standards for specific source^.^^^-'^^ The assessment of health hazards in an adequate manner to set regulatory limits for pollutants is well recognized as a complex and onerous t a ~ k . ~However, ~ ~ - ~increases ~ ~ in deaths in urban populations during acute pollution episodes in London, the Meuse Valley, Osaka, New York, and Donora (Pennsylvania) and detailed epidemiological studies have led to the introduction of pollution indices to relate health and For total suspended particulates (TSP) the W.H.O. has put forward a tentative interim guideline of 60-90 pg m-3 as an annual mean beyond which effects of long-term exposure on health are p r ~ b a b l e ,For ~ short-term exposures, the 24 h guideline is 150-230 pg m-3.5 In the case of smoke, guidelines for exposure limits are 100-150 pg mP3(24 h mean) and 40-60 pg mP3 (annual arithmetic mean).5 The Greater London Council guideline for TSP is 40 ,ug m-3 as an annual mean measured in daily intervals, with 98% of observations below 120 pug m-3.731In the US the primary air-quality standard for TSP is 75 pg m - 3 (annual geometric mean, 24 h values), with 260 pg m-3 as a 24 h value not to be exceeded more than once a year;’2a a standard for the fine particle fraction of TSP is under review. Dangers of pneumoconiosis from dust in quarries have been assessed by comparison with the UK coal mines (respirable dust) limit of 4.3 mg dust rnb3 at the coal face, that contains ( 5 % A pollutant standards index (PSI) based on TSP and levels of four gaseous pollutants gives a dimensionless value intended for public information purposes;732 the PSI concept and guidelines are approved by the EPA.733For example, a daily air-quality index is published by the New Jersey Bureau of Air Pollution Control, In Canada, good correlations based on measurement of TSP, SO,, and are reported between hospital admissions for respiratory complaints and a calculated air-pollution index (API) from measurements of haze and Subsequently, a new urban air-quality index was applied to 11 Canadian cities, taking into account both the magnitude and frequency of short-term (daily) pollution episodes and also annual concentrations of pollutants, namely TSP, SO,, CO, NO,, and 03.736 Effects on man of exposure to H,S04 aerosols and SO:- have

’”‘Air Pollution’.

3rd Edn., Vol. 5, ‘Air Quality Management’. ed. A. C . Stern, Academic Press, New Ynrk, 1977. de Nevers. J . Air Pollut. Control Assoc., 1977, 27. 197. US Environ. Protection Agency, Federal Regisier. 1978. 43. 9452. 7 2 h S L. Wilcox, E. L. Keitz. and L. J. Duncan. in ref. 88, p. 124 I . 72”lmpact of Energy Production on Human Health‘. ed. E. C. Anderson and E. M. Sullivan, USERDA Symp. Ser. 39. NTIS, Springfield, VA. 1976. 12’ B. G. Ferris, J . Air Pollut. Control Assoc., 1978. 28.482. 7 2 y H. Kolb, We//erLeben, 1978. 30, 230. W. R. Ott and G. C. Thom, J . Air Pollut. ControlAssoc.. 1976, 26,460. 7 3 ’ M. J . Gittins, Clean Air, 1978. 8, 19. 7 3 * W. R. Ott and W. F. Hunt. jun., J . Air Pollui. Control Assoc., 1976, 11, 1050. ’ j 3 US Environ. Protection Agency, Publ. EPA-450/2-76-013. N. Carolina, 1976. 7 3 4 V. J. Marchesani, J. N. DePierro, T. A. Juchnowski, R. J. Pfannenstiel, J. J. Serkies, and A. S. Thornton, Atmos. Environ.. 1975. 9. 683. 7 3 5 D. Levy, M. Gent, and M. Newhouse, in ref. 88, p. 1263. 7 3 h M. H. Doan and C. East, WaferAir Soil Polhi., 1977. 8, 4 4 I .

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been discussed r e ~ e n t l y ,although ~ guidelines are not yet available from W . H . 0 . 5 The secondary nature of these pollutants presents a complex problem, but it is considered that in the first instance, standards could be based on total water-soluble SO$- in air particulates, perhaps within the range 5-15 pg m-) as an annual average. 7 3 7 A Cumulative Hazard Index (CUMEX) has been developed to assess intake and absorption of single pollutants by man, and is applied to releases of Cd by a smelter The index is the ratio of integrated exposure to the body or critical organ to the limit assigned from considerations of health risk. Hazards to man from airborne metals have sometimes been estimated by comparison with Threshold Limit Values (TLV) for the workroom e n v i r o n m e r ~ t ,by ~ ~using ~ . ~ ~h ~t h of the TLV as a guideline for maximum acceptable levels in the ambient atmosphere, although this is not specifically recommended by the originators of T L V ' S . It ~ ~is~noted that in urban areas, Pb concentrations may reach 1% of the TLV for industrial workers, a level not usually attained by other metals.741 National ambient air-quality standards for metals have been summarized;723in 1979 the USEPA issued a revised standard of 1.5 pg Pb mP3 (based on 3 month average) intended to prevent levels in children's blood exceeding 30 pug Pb/100 ml.742In some countries, standards are set for deposited particulates,723e.g., 0.65 g rn-' day-' (as monthly average) in W. Germany. Effects on Visibility.-A reduction in visual range in the atmosphere, caused by an increase in airborne particles that affects light scattering and attenuation, involves both primary and secondary aerosols, and may be experienced in rural as well as urban area^.^^^*^^^*^^^ The implications for agriculture of reduction in intensity of light at ground level have been ons side red,^^^,^^^ in addition to requirements of a visibility impairment model to assess the impact of near-source and regional pollution by excessive particulate loadings.746However, visual opacity of smoke plumes is not well related to mass emissions of particulates and other factors such as physical properties of the TSP and observer location must also be considered to avoid rni~interpretation.~~~ Particulates have sometimes caused atmospheric discolouration by wavelength-dependent light scattering as in Los Angeles smog.748

M. D. Rowe. S. C . Morris, and L. D. Hamilton. J . A i r Pollut. Control Assoc., 1978, 28. 772. P. J . Walsh, G. G . Killough, D. C . Parzyck, P. S. Rohwer, E. M . Rupp, B. L. Whitfield. R. S. Booth, and R. J . Raridon, Rep. O R N L 5263. Oak Ridge Natl. Lab., Tennessee. 1977. '" 'Threshold Limits for Chemical Substances in Workroom Air', Am. Conf. Govt. Indust. Hygienists, Cincinnati, Ohio. 1979. 74"'Threshold Limit Values for 1977', Health and Safety Executive Guidance Note EH 15/77, H.S.E., London. 1977. ''' 'Pollution in the Atmosphere', Study Group Rep. R. Soc., London, 1978. 742 'Air Quality Criteria for Lead'. US Environ. Protection Agency, N. Carolina, 1978. 7 4 ' C . N. Davies, J . Aerosol Sci.. 1975, 6, 335. 744 H. A. Bridgman. Solar Energy, 1978, 21, 139. 745 Report E R D A - 12 17-75. Chemist/Meteorologist Workshop (USERDA), NTIS, Springfield, VA, 1975. 74h R. W . Bergstrom and D. A. Latimer, in 'Proc. 3rd Conf. Atmos. Radiat.', Am. Met. Soc., Boston, 1978. p. 14. 747 A. Weir, jun., D. G . Jones. L. T. Papay, S. Calvert. and S. C. Yung, Enzyiron. Sci. Techno/., 1976. 10, 539. 74R R. B. Husar and W . H . White, Amos. Enzliron.. 1976. 10, 199.

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64

Environmental Chemistry

In rural areas, constants relating visibility to the mass concentration of particles showed wide variation between 2 x lo-* and 1 x lo-’ g m-3 km during wind erosion of soil, with higher values under drought conditions, and it proved difficult to predict mass concentrations of dust from measurements of ~isibility.’~~ In an urban aerosol analysed for particle-size associations of 8 elements and total mass at four levels of visibility, it was found that increases in fine particles (d = 0.1-1 pm) were particularly associated with a decrease in visibility and that these contained high mass concentrations of SO:- relative to NO;, C1, NH:, and C.750At a visual range of 8-13 km the TSP load was 232 pg m-3 compared with 59 pg mP3for visual range >26 km in a background area.75oSignificant effects of SO:- aerosols on reduction in visibility are reported by other w o r k e r ~ ~ ~ and l *G ~ e~ ~* r g i i ~ has *~ reviewed the sources, global distribution, and effects of SO:- particles on light scattering and absorption. Photochemical pollution in London in 1976 was considered a major factor in formation of haze,753and reduction in visibility caused by SO:- aerosols in photochemical smog is particularly evident at low humidities.754 In Los Angeles aerosol, SO:- and NO; contributed nearly 60% to the total m-1.755 light-scattering coefficient (b,,,,) of 6.4 x Examination of air trajectories over Sweden has shown that maximum light scattering and absorption is coincidental with peak levels of SO:-, NH:, and TSP loading experienced during airflow from S.E. to W. In the stratosphere, formation of haze clouds at 25 km altitutde in the absence of volcanic dust incursions are believed to result from interchange of particles across the tropopau~e.~~~ Effects on the Global Albedo and Climate.-Increases in particulate matter in the atmosphere may affect cloud droplet formation and precipitation, reduce the amount of solar radiation that reaches the ground, reduce the cooling of the surface layer of the earth at night and influence the global However, controversy still remains as to whether the presence of particulate material exerts a net warming or cooling effect to enhance or offset the global warming predicted In general it is from increases in CO, and chlorofluoromethanes in the atm~sphere.~ believed that aerosols are less important than CO, with respect to the global heat balance although regional effects of high TSP are not excluded.762In addition,

E. M. Patterson and D. A. Gillette, Atmos. Enuiron., 1977, 11, 193. R. K. Patterson and J. Wagman, J. Aerosol Sci., 1977,8,269. 7 5 1 J. B. Barone, T. A. Cahill, R. A. Eldred, R. G. Flocchini, D. J. Shadoan, and T. M. Dietz, Amos. Enuiron., 1978, 12,2213. 752 B. P. Leaderer, T. R. Holford, and J. A. J. Stolwijk, J . Air Pollut. Control Assoc., 1979, 29, 154. 753 D. J. Ball and R. E. Bernard, Nature (London), 1978,271, 733. 754 W. H. White, Nature (London), 1976, 264, 735. 755 W. H. White and P. T. Roberts, Atmos. Enuiron., 1977, 11, 803. 756 J. Heintzenberg and C. Tragardh, Rep. AC-48, Dept. Meteorology, Internat. Meteorol. Inst., Univ. Stockholm, 1979. 757 F. W. Gibson, Nature (London), 1976, 263,487. 758 L. A. Barrie, D. M. Whelpdale, and R. E. Munn, Ambio, 1976, 5 , 209. 7 5 9 G. D. Robinson, in ‘Energy and Climate’, Natl. Acad. Sci., Washington DC, 1977, p. 61. 760 H. Hidalgo, IEEE Trans. Geosci. Electron., 1978, 16,4. 761 E. W. Barrett, IEEE Trans. Geosci. Electron., 1978, 16, 62. 762 W. W. Kellogg and S. H. Schneider, IEEE Trans. Geosci. Electron., 1978, 16,44.

749

750

Inorganic Particulate Matter in the Atmosphere

65

considerable changes in global and surface albedo have been caused by deforestation, salinization, and d e ~ e r t i f i c a t i o n .As ~ ~ Flohn ~ 764 has pointed out, the role of particulates and CO, on global temperature changes must be viewed against a background of natural effects such as volcanic eruptions and changes in Arctic sea ice, snow cover, and oceanic evaporation. Bolin and Charlson 765 reported that scattering of solar radiation by tropospheric SO:- aerosols might lower the average temperature of the N. hemisphere by 0.1 "C, excluding any effects of this aerosol on the infrared flux or on cloud formation. Some workers believe that with less particulate pollution, by emissions controls on industry, a cooling effect of particles will no longer offset global warming (greenhouse effect) from anthropogenic emissions of CO,, with the possibility of -0.5 "C increase from 1970 to 2000.766 From an inventory of particulate production estimates and a historical summary of anthropogenic aerosols and climatic change, Dittberner 7 6 7 considers that the importance of volcanic emissions, industrial-derived aerosols, and CO, on climatic change is roughly comparable. A layer of Sahara dust over the Cape Verde Is. in July 1974 depleted -20% of the direct solar energy flux mainly by absorption but with some b a c k s ~ a t t e r i n g . ~ ~ ~ The estimated average solar heating rate of a Sahara dust layer at 1-5 km over the tropical Atlantic (for optical depth 2.0,and dust loading of 7.5 g rn-, under clear sky conditions) was 3.1 "C day-', rising to 4.3 "C day-' with overcast conditions below the dust layer base:769this aerosol absorbs strongly in the short-wave region of the solar spectrum so that increasing dust load gives relatively large heating rates in the lower troposphere and cooling near the A modified radiative transfer model has been used to examine the effects of heavy dust layers on infrared radiative cooling of arid regions with special reference to the Rajasthan Desert in N.W. India and indicates an increase in such cooling in the lower troposphere of Modifications by cloud layers to the influence of aerosols on the radiative heat balance of the earth have been e ~ a m i n e d . ~ ~ ~ . ~ ~ ~ With respect to the influence of stratospheric aerosols on climate, the presence of submicrometre particles derived mainly from volcanic activity and supersonic transports (SSTs), having long residence times of -3-10 yr, has received a t t e n t i ~ n . Past ~ ~ ~volcanic - ~ ~ ~ activity such as the 1963 Mt. Agung eruption are well correlated with elevated atmospheric heating rates and a temporary reduction in surface temperatures of the earth, whereas such climatic impact is not anticipated

-

C. Sagan, 0. B. Toon, and J. B. Pollock, Science, 1979,206, 1363. H. Flohn, in 'Global Chemical Cycles and their Alteration by Man', ed. W. Stumm, Dahlem Konferenzen, Berlin, 1977, p. 207. 765 B. Bolin and R. J. Charlson, Ambio, 1976, 5,47. 766 M. I. Budyko and K. Ya. Vinnikov, in ref. 764, p. 190. 767 G. J. Dittberner, IEEE Trans. Geosci. Electron, 1978, 16,50. 768T. N. Carlson and R. S. Caverly,J. Geophys. Res., 1977, 82, 3141. 769 T. N. Carlson and R. S . Caverly. in ref. 113, p. 160. 710 Harshvardhan and R. D. Cess, J . Quant. Spectrosc. Radiat. Transfer, 1978, 19,621. 7 7 1 S. Moriyama, Atmos. Environ., 1978, 12, 1875. 772 Harshvardhan and R. D. Cess, Tellus, 1976, 28, 1. 7 7 3 B. M. Herman, S . R. Browning, and R. Rabinoff,J. Appl. Meteorol., 1976, 15. 1057. 774 J. A. Coakley and G. W. Grams,J. Appl. Meteorol., 1976, 15,679. 775 J. Bensimon and B. Dehove, Met. (Paris) 6th Ser., 1977, No. 10, 15. 763

764

Environmental Chemistry

66 2600 i2200

1400 1200

1800

1000

1400

800

LL 0

2

600

1000

1400 I I I I I 600 I 19461950 1954 1958 1962 1966 1970 1974

I

Figure5 Injuence of volcanic dust at high latitudes. Annual (T, + T,) MDD totals at Thule, northwestern Greenland, showing the abrupt decrease in overall Summer warmth' after the eruption of Mount Agung in 1963. A melting degree day ( M D D ) is the difference between 0 " C and daily maximum (T,MDD) or minimum (T, MDD) temperatures, wher?the latter are above 0 "C (Reproduced by permission from Nature (London), 1978,271,735)

from S S T S . Observations ~~~ of the number and SO:- content of volcanic dust bands in ice cores from Greenland and Antarctica indicate the important influence of volcanic activity on cooling during the 'Little Ice Age' (- 1450-19 15) and on later stages of the last major ice age (the Wisconsin, -75 000-12 000 BP).F76 Details of 28 volcanic eruptions between 1883 and 1968 that caused stratospheric dust injections over latitudes 39"s to 64"N are listed by Oliver.777 From a study of the stratospheric dust veil index (DVI: a time- and area-weighted radiation loss parameter) and CO, levels from 1870-1969, it was found that these factors accounted for 65% of the variance in N. hemisphere temperature^.^^^,^'^ Values of DVI in the N. hemisphere in the mid-1960's were 1100 (after Mt. Agung event), the greatest since the eruption of Krakatau in 1883, which gave DVI values of 1500;7R0high levels of diffuse radiation after 1964 and relatively low values of direct solar radiation, typical of volcanic dust, appear to have decreased the summer warmth in the Canadian Arctic (Figure 5) with the result that melting of snow and ice is reduced7*0 (Figure 6). Heterogeneous reactions between volcanicderived particles and trace gases such as C1 injected to the stratosphere possibly cause ozone column depletion of < 1% for a major eruption equal to Mt. A g ~ n g . ~ ~ ' Inadvertent modification of climate on a local, regional, and global scale by enhanced formation of cloud condensation nuclei (CCN) and ice nuclei (IN) also demands c ~ n s i d e r a t i o n . ~In~ ' the US east coast region, CCN concentrations in urban air were from 1000-3500 crnp3, an order of magnitude greater than in continental or maritime atmospheres.782On a global scale, formation of CCN from B. Baldwin. J. B. Pollack, A. Summers. 0. B. Toon. C. Sagan, and W. Van Camp, Nature (London). 1976,263,551. 7 7 7 R. C. Oliver, J . Appl. Meteorol., 1976, 15, 993. "* M. K. Miles and P. B. Gildersleeves. Meteorol. Magazine, 1977. 106, 314. 7 7 9 M. K. Miles and P . B. Gildersleeves. Nafure (London), 1978, 271, 735. 7Rfl R. S. Bradley and J . England, Nature (London), 1978, 271. 736. 7 8 1 R. S. Stolarski and D. M . Butler, Pure A p p l . Geophys. (Bade). 1979. 117, 486. 782 L. F. Radke and P. V . Hobbs, Science, 1976, 193. 999. 776

lnorganic Particulate Matter in the Atmosphere

67

0 -500

- 1000

-1 500 NI

E 0

A

-2000 -2500

-3000

-3500

-4000

I

1

1

1

1

1

1

1950 1955

1

~

l1 , , , , I , , * , l , , , ,

1960 1965 1970

Figure 6 Glacier mass balance at high latitudes. Reconstruction of cumulative mass loss on the north-west Devon Ice Cap since 1947. The abrupt change in net loss since 1963 is clearly shown (Reproduced by permission from Nature (London), 1978,271, 735)

anthropogenic sources may be comparable to a natural production rate of s - ’ . ~ ~Basic , processes by which ice-forming nuclei induce vapour and liquid nucleation have been reviewed.783The formation of CCN in urban pollution episodes is accelerated by sunlight and results from coagulation and photolytic reactions to give larger, more water soluble particles.784 Project ‘Metromex’ was initiated in 1969 to study the influence of the St. Louis (Missouri) metropolitan area on temperature, cloud microstructure, and p r e ~ i p i t a t i o n plumes ; ~ ~ ~ of SO, undergo gas to particle conversion to form Aitken particles, which then grow to CCN. Zones of higher rainfall than the area average A scavenging effect of fog on CCN in are identified up to 30 km from the the St. Louis atmosphere has been shown by aircraft surveys with a CCN spectrometer.786An increase in rainfall downwind of industrial zones of Bombay is also related to greater numbers of CCN.787Plumes from paper mills increased the concentrations of large (d = 0.1-1 pm) and giant (d > 1 pm) CCN by five-fold with a corresponding increase in concentrations of large droplets (d 2 30 pm) in clouds located in the plume, that results in frequent rain showers at 2-5 km H. K . Weickmann, in ‘Proc. 3rd Int. Workshop Ice Nucleus Measurements’, ed. G . Vali, UGGI/IAMAP, 1976, p. 16. 784 C. C. Van Valin, R. F. Pueschel, F. P. Parungo, and R. A. Proulx, Atmos. Environ., 1976, 10, 21. 78s R. R. Braham, in Proc. 2nd W.M.O. Scient. Conf. Weather Modification, W.M.O. Rep. 443, Geneva, 1976, p. 435. m6 V. K. Saxena, in ref. 30, p. 152. 787 A. M. Selvam, A. S . Ramachandra Murty, S. K. Paul, R. Vijayakumar, and Bh. V. Ramana Murty, Atmos. Environ., 1978, 12, 1097. 783

68

Environmental Chemistry

downwind.’** The evidence for effects of power stations on precipitation has been summarized. 789 Submicrometre aerosols emitted from a copper smelter were reported as active CCN, although the relatively narrow size distribution inhibits coalescence and consequently a haze or fog may appear.79oThe fact that more IN appeared downwind was explained by near-distance deactivation of plume aerosols by gaseous emissions, such as SO, and NO,, that volatilize during dispersion to distant regions.79oWith reference to fly ash, if the volatile surface coating is evaporated, it enhances the relatively poor ability of these particles as IN.136Analysis of active IN from rocket exhaust aerosol indicated that most contain mixed particles of Al, Ca, and S.791 It is proposed that weather could be modified on a mesoscale by dispersal of submicrometre carbon particles in the upper troposphere.792This would absorb solar energy and assist cirrus cloud formation, leading to a lower daytime surface temperature of benefit to agriculture in certain seasons. A reduction in long-wave radiative cooling at night would lessen damage by frost.

8 Future Research Needs and Conclusions Recognition of the potential for long-distance transport of pollutants in the atmosphere and their complex effects on biological systems has helped to initiate interdisciplinary studies in recent years, and continued attention has been given to control of emissions by industry. In 1977 approval was made for continuation of the European Communities Environmental ‘Programme of Action’ designed to develop environmental quality objectives and standards for control of air and water pollution, to examine global aspects of pollution, and to study management of natural resources.793 Requirements for atmospheric pollution research on global, regional, and local scales were reviewed by a Royal Society Study areas for further work on inorganic particulates were identified as ( i ) high altitude aerosols and their influence on climate, (ii) removal and effects of metals and SO, deposited to soil, plants, and water, (iii) impact of accidental discharges, and (iv) transport processes. In the US, recommendations have been made for research to assess the environmental effects of fossil-fuel combustion in the next decade.794 The significance of climatic change following increases in particulate matter and CO, in the atmosphere is not well established, although these factors have been implicated with expansion of the Sahara desert into agricultural regions.795Recent eruptions of Mount St. Helens volcano, Washington, in May 1980 have made substantial contributions to the stratospheric dust and modern remote sensing techniques should yield valuable data on dust trajectories and residence times of particulates.

”’ E. E. Hindman, P. M. Tag, B. A. Silverman, and P. V. Hobbs, in ref. 785, p. 21. S . R. Hanna, in ref. 519, p. 88. F. Parungo and R. Pueschel, in ref. 30, p. 156. 79‘ F. Parungo and P. A. Allee, . I Appl. . Meteorol., 1978, 17, 1856. 792 W. M. Gray, W. M. Frank, M. L. Corrin, and C. A. Stokes, in ref. 785, p. 425.

789 790

CEC, ‘State of the Environment’, 2nd Rep., E.E.C. Luxembourg, 1979. D. Cohan and D. W. North, Rep. EA-1018, Electric Power Res. Inst., Palo Alto, CA, 1979. 7 9 5 J. 0. Ayoade, Arch. Meterol. Geoph. Bioklimatol. Ser. B., 1971, 25, 61. 796 A. Tucker, Manchester Guardian, 1980, 2nd June, p. 3. 793 794

Inorganic Particulate Matter in the Atmosphere

69

Improved information is needed on biogeochemical cycling of elements for an accurate appreciation of disturbances caused by excessive release to the atmosphere and subsequent deposition to terrestrial and aquatic ecosystems; it is now believed that the rainfall flux of Hg to the open ocean has been over-estimated by more than an order of magnitude.797The removal rates of pollutants from the atmosphere by wet and dry deposition should be examined in detail under seasonal conditions that influence soil and plant cover. Little information exists on the chemical forms and oxidation states of metals in air and rainwater. Detailed recommendations for further research into sulphur emission, behaviour, and modelling were made by four workshops following the Dubrovnik Symposium.798Since the oxidation of SO, to SO$ can be catalysed by Mn and other metals, studies on the transport and fate of SO, should consider the concentrations of particulate metals in the atmosphere. New combined techniques of microscopy and multi-element analysis are proving extremely valuable to characterize particles emitted by natural and industrial sources. Wider application of these methods is anticipated to examine the distribution and correlations of elements in particle-size modes, and particulate composition in relation to sources and air-mass trajectories. Intercalibration of sampling and analytical methods is essential, particularly to improve the reliability of global monitoring and international projects on transport of pollutants. Application of physical and chemical methods of analysis to measurements in the field could reduce problems of sample contamination and deterioration in storage. Continuous measurement of airborne particulate matter is essential in urban areas to record high episodic levels of pollutants and for public reassurance on health risks. Information on long-term trends in concentrations of pollutants is required to relate to changes in major industrial activities and energy production. Development and application of personal air monitors is important to improve exposure estimates of residents to elements in urban areas within which the pollution levels may be very variable.745The Health and Safety Commission has recently advised that exposure of individuals to asbestos in the non-occupational environment should be measured.65 The possibility of synergistic effects of pollutants on human health requires careful attention; urban pollution being seldom restricted to single elements or gaseous species. Entry of airborne metal pollutants into the body by ingestion of contaminated vegetables and water, in addition to inhalation, has received little attention in studies on urban pollution but may contribute significantly to the intake of metals such as Cd and Pb.

Acknowledgments. I am very grateful to Mrs. Joyce Cowlard, Meteorological Office Library, Bracknell, Berks., and Margaret Cann, Environmental and Medical Sciences Division, AERE, Harwell for their co-operation with the literature survey work I carried out within the scope of this review.

'" T. R. Fogg and W. F. Fitzgerald, J . Geophys. Res., 1979,84,6987. '"Anon., Atmos. Environ., 1978, 12, I .

The Elemental Content of H u m a n Diets and Excreta BY H. J. M. BOWEN

1 Introduction The inorganic constituents of human diets have been studied for two reasons. Diets deficient in any of the essential elements can lead to numerous and varied malfunctions, which can often be cured by restoring the missing element.’V2Diets containing excessive amounts of almost any element can be toxic, but a change to a normal diet may not relieve the toxic symptoms quickly, as the retention time in the body may be long. Although information about the tolerable limits of concentration of elements in diets is meagre, it seems that both deficient and toxic diets are rare and local among human populations, and are more often seen in animals.2 2 Outline of Ingestion, Absorption, and Excretion The physiology of ingestion and excretion is too well known to need further description. Normal adults are in a steady state with respect to elemental inputs and outputs. Reference Man, a convenient fiction supposed to weigh 70 kg, is assumed to eat 750 g dry matter and drink 1.95 1 water per day; his excretion averages 30 g faeces (dry matter) and 1.4 1 urine per day.3 He also breathes 23 m3 of air each day, which contains traces of all the chemical elements. However, for almost all the elements more than 90% of the mass ingested comes from food. In exceptional localities, drinking water can provide a significant fraction of the intake of a r s e n i ~ , ~ f l ~ o r i n e ,selenium,6 ~ and uranium.’ Excretion in sweat, in hair, or in other ways appear to be of minor importance compared with urine and faecese3 Human diets are notoriously variable, but data on the relative proportions of the

’ A. S. Prasad and D. Oberleas (ed.), ‘Trace Elements in Human Health and Disease’, Academic Press, London, 1976. J. Underwood, ‘Trace Elements in Human and Animal Nutrition’, 4th Edn., Academic Press, London, 1977. W. S. Snyder (ed.), ‘Report of Task Group on Reference Man’. Pergamon, London, 1975. J . M. Harrington, J . P. Middaugh, D. L. Morse, and J. Housworth, A m . J . Epidemiol., 1978, 108, 317. C . M. Jones, J. M. Harries, and A. E. Martin, J . Sci.Fd. Agric., 1971, 22, 602. I. Rosenfeld and 0. A. Beath, ‘Selenium’, Academic Press, London, 1964. p. 286. A. V. Berdnikova, Vopr. Pitan., 1964, 23, 17.

* E.

70

The Elemental Content of Human Diets and Excreta

71

main components are available for some countries.8*yAs most common foodstuffs have been analysed, some authors have combined data to calculate average dietary intakes from these countries.'O Examples of diets with abnormal amounts of trace elements include those containing unusual amounts of sea food (rich in As, Br, Cd, Hg, I, Se, and Zn) or Brazil nuts (rich in Ba, Se, and Sr). Urban and institutional diets have been most studied, and since the food sources are numerous and widespread it is perhaps not surprising that their elemental contents are similar all over the world. More studies are needed on rural populations living almost exclusively on local foods. These can illustrate surprising results, such as zinc deficiency in Iran and excessive iron in parts of Africa,l3~l4and selenium toxicity in Colombia.6*l 5 Selenium deficiency has recently been reported in part of China (see ref. 101). Although specified concentrations of elements such as iron and zinc have been recommended in the USA,' it has not been proved that these apply to all individuals or to all countries. In particular, countries where the mean adult weight is lower than in the USA may have lower dietary requirements. Since few human feeding experiments are carried out for periods of more than one year (0.015 x lifetime), evidence on this point is hard to obtain. A few hospital patients are fed on artificial diets of constant elemental composition, but a recent review concludes that these are not cost effective (see ref. 262). While measurements of the masses of food ingested are straightforward, estimates of elemental absorption across the gut wall are more controversial. As a rough approximation, we can estimate the percentage absorption of any element across the gut from the ratio of urinary excretion to dietary intake. This is a fairly good approximation for mobile, rapidly metabolized elements, but takes no account of two side effects. These are (i) re-excretion of absorbed elements from the bile duct into the faeces, and (ii) the long retention times of some absorbed elements by specific organs, e.g., cadmium in kidney; iron in ferritin; barium, calcium, lead, strontium, etc. in bone.I6 A powerful method for studying absorption and retention by the body involves the occupancy principle. l 7 This method, which compares the oral and intravenous administration of radioactive tracers, has been used to show that the bromide ion is almost totally absorbed across the gut wa11.18 Note that the inhalation of elements into the lung can be the equivalent of an intravenous injection, so that inhalation of poisonous materials is more hazardous than ingesting them orally. However most F.A.O., Per capita food consumption data, Food balance sheets, average for 1964-6, Food and Agriculture Organization, Rome, 197 1. J . T. Tanner and M. H. Friedman,J. Radioanal. Chem., 1977, 37. 529. l o G. N. Schrauzer, D. A. White, and C. J . Schneider. Bioinorg. Chern., 1977, 7. 35. H. A. Ronaghy, in 'Clinical Applications of Zinc Metabolism', ed. W. J . Pories, W. H. Strain, J. M. Hsu, and R. L. Woosley. C. C. Thomas, Springfield, IL, 1974. p. 119. l 2 A. S. Prasad, 'Trace Elements and Iron in Human Metabolism', J . Wiley, New York, 1978. l 3 C. I. Waslien in ref. I , VoI. 2, p. 347. l 4 D. J. Horvath, in 'Trace Substances and Health', ed. P. M. Newberne, M. Dekker, New York, 1976, p. 319. ''J. Ancizar-Sordo, Soil Sci.,1947, 63, 431. l 6 H. J. M. Bowen, 'Environmental Chemistry of the Elements', Academic Press. London. 1979. " J . S. Orr and F. C. Gillespie, Science, 1968, 162. 138. I s F. C. Gillespie, J. Shimmins, and J. M. A. Lenihan. Radiochem. Radioanal. L.eti.. 1970. 4, 43.

Environmental Chemistry

72

elements will be inhaled as particulate matter, whose rate of absorption from the lungs will be determined by the solubility of the particles in blood. In the Chemical Industry, toxicity is sometimes caused by inhalation of excessive As, Be, Cr, Mn, Ni, Pb, Sb, V, and other elements, but there is little quantitative data relating inhalation rates to t o ~ i c i t y . ’ ~ Investigations of absorption across the gut wall are hampered by our ignorance of the chemical nature of most elements in prepared or partially digested food. For example, much of the iron in the diet is ingested as pcrphyrin derivatives such as myoglobin, but it is not known how much of the metal is set free on digestion or which chemical form of iron is most readily absorbed. In addition common organic constituents of foods, such as phytates, have substantial effects on the absorption of calcium, iron,” and zinc.I2 Aluminium is not normally regarded as toxic,19but may become so in the diets of patients undergoing dialysis.*’ Organometallic derivatives of lead and mercury have quite different lipid solubilities from those of the cations of these metals, so that their percentage absorption is increased.’,22 This needs further study since it now appears that several B-Group elements, notably arsenic, selenium, and tin, can occur as methyl derivatives in the e n ~ i r o n r n e n t . ~ ~ - ~ ~ As well as interactions with organic substances, there are almost certainly many mutual interactions between elements with respect to human dietary ab~orption.~’ Examples of such interactions include copper and molybdenum,2 and mercury and selenium,2* which have been investigated in mammals other than man. It is worth pointing out here that any extrapolation from the diets of laboratory animals or farm stock to those of human beings must be interpreted with caution. Thus studies of rodents give useful information on elemental t o x i c i t i e ~but , ~ ~ are limited by the short life-span of the animals.30In experiments with farm animals, whose life-span is also much shorter than that of man, the possession of a rumen by cows and sheep makes their digestive system rather different. Grazing mammals ingest much more soil and atmospheric fall-out than do humans, and neither wash nor cook their food before they eat it.

3 Methodological Problems The collection of food samples, including daily diets, for analysis is subject to an uncertain degree of contamination from dust, container materials, and laboratory handling. 24-h urine samples can readily be obtained from inmates of institutions, E. Browning, ‘Toxicity of Industrial Metals’, 2nd Edn., Butterworths, London, 1969. S . R. Williams, ‘Nutrition and Diet Therapy’, C. V. Mosby, St Louis, MO, 1977. 2 1 H. L. Elliott, F. Dryburgh, G. S . Fell, and A. I. Macdougall, Br. Med. J., 1978, 1, 1101. 22 S . Moeschlin, ‘Poisoning’, Grune and Stratton, New York, 1965. 23 R. S . Braman and C. C . Foreback, Science, 1973, 182, 1247. 24 J. M. Wood, H. J. Segall, W. P. Ridley, A. Cheh, W. Chudyk, and J. S . Thayer, in ‘Heavy Metals in the Environment’, ed. T. C. Hutchinson, Toronto, 1975, Vol. 1, p. 49. M. 0. Andreae, Anal. Chem., 1977,49,820. 26 R. S . Braman and M. A. Tompkins, Anal. Chem., 1979,51, 12. 27 C. H. Hill, in ref. 1, Vol. 2, p. 28 1. 28 J. Parizek and I. Ostadalova, Experienria, 1967, 23, 142. 29 B. Venugopal and T. D. Luckey, ‘Metal Toxicity in Mammals’, Plenum Press. New York, 1978, Vol. 2. 30 H. A. Schroeder and D. K . Darrow, in ‘Chemical Analysis of the Environment and Other Modern Techniques’, ed. S . Ahuja, E. M. Cohen, et al., Plenum Press, New York, 1973. l9

2o

’’

73

The Elemental Content of Human Diets and Excreta Table 1 Elemental content of adult human diets mg X day-'

X

A g 0.07

Al

As

Country

0.027 tO.0004--0.007 0.002-0.016 0.04

Many UK Italy Sweden USA

0.02?

Median

45 (7-500) 2.3 0.04- 1.4 20 5.3-9

Many UK Sweden USA USA

I O?

Median

1

0. I 0.055 0.08 (0.006-0.19) 0.027 (0.014-0.04) 0.07-0. I7 0.32 0.23-0.75 calc. 0.0 I

Many UK Scotland Germany Austria Japan Korea Many USA

0. I

Median

Au (0.007 0.002 (
Ref. 3 40 42 38 34

3,36 40 38,43 9, 34 35

3.36 40 44 37 45 46-48 49 10

50

UK Germany

40 37

Sweden

38,43

X

B

Median

2.8 1.3 0.39 0.6-1.6

UK USA USA USA

1.3

Median

Ba 0.6 0.44 (0.01-1.7) 0.75 (0.44-1.8) 1.6 <0.2 5 -0.7 2 0.5 Re 0.012 <0.015

UK Germany USA USA USA

Cd 0.15 0.09-0.39 calc. 0.064 0.02 I 0.04 I 0.01-0.02 0.04-0.18 0.04-0.059 0.054-0.13 0.013-0.016 0.03-0.05

Median USA UK

3,36 40

~~

Bi

Br

(0.01

Median

t0.005 0.02

UK USA

40 3.36

7.5 (0.8-12) 8.4 2.5 (1-5) 1.5-6 0.8 2.3

Many UK Germany Sweden Russia Korea

3,36 40 37 38,43 51 49

4

Median

Counrrr Many UK Germany India Canada USA USA USA

R4 3 40 37 52 53 54 9.34 35.55

Median Many Many UK Germany Italy Sweden Russia Japan USA USA USA

3 10 40 56 57 38,43 58 59,60 32 61 50,62-64

0.04

Median

Ce 0.0 16-0.24

Sweden

38

CI

Many UK Germany USA

3 40 37 9

5200 (900-12000) 5 400 6000 (2600- I 1 000) 6600 5 800

40 3.36 34 35

40 37 3. 36 34 35

I

1100

Co

0.000 I ?

mgXday

C a 1100 I400 380 (35-880) 710 880 960-1980 760- 1300 1000- I400

Many Germany Italy Russia Sweden Canada USA USA USA

0.02

Median

Cr 0.15 0.036-0.07 calc. 0.32 0.062 (0.01 1-0.19) 0.0054.44 0.694.82 0.13-0.1 7 0.15 0.13 (0.076-1.1) 0.0394.19 0.28 0.034.4 0.37-0.82

cs

Median

0.3 0.017 (0.003-0.046) 0.0 1 (0.002-0.03) 0.03 0.0075-0.01 7 0.1 0.04 0.16 0.64- 1.4

Many Many UK Germany Italy Russia Japan India Egypt NZ Canada USA USA

0.05

Median

0.01 0.0 13 0.013 (0.004-0.027) 0.031 (0.001-0.12) 0.0 1-0.0 I5 0.01 1

Many UK Germany Italy Sweden Japan

0.013

Median

3, 36 37 39.42 65 38.43 66 9 34 32

3 10 40 37 39,42, 57 13 13 52 67 68 66 13,34,36, 69 32

3 40 37 39-42 38.43 70

Environmental Chemistry

74 X

mgXday-l

F

Fe

Many Many UK Germany Italy Sweden Russia Japan Korea India NZ Canada USA USA USA

2.5

Median

1.8 (0.3-2.5) 0.3-0.5' 5.5 1.2 4.5 0.2-0.45* 0.9 I- 1.7 2-5

Many UK UK Russia Japan USA USA USA

2

Median

I6 (9-20) 11-14 23 14 (5-32) 9 (1.8-22) 4-20 19-39 9--39 20-22 19 6.5-30 17-4 1 59-390

Many Europe UK Germany Italy Sweden Russia Asia Australia Canada USA S. America Africa ~

3, 36 40,7l 37 57,72 38,43 13 2,46 49 52 68 66 9 64.73-15 35

3, 36 40.76 77 78 79

5 80 81

1.5 Hg 0.015(0.002-0.031) 10.016 0.06 0.012 (O.oOl--O.l5) <0.0005-0. I 0.004-0.003 0.014 0.02 0.0 1 0.006 0.0029

0.01

3,36 13 40 37 39.42 38,43 13 13,52 13 66 9. 13. 35, 55 13 13

~~

UK USA

40 3

Many UK Scotland Germany Italy Sweden Belgium Korea Canada USA USA

3, 36 40.82 83 31 39.42. 57, 84 38.43,85 86a 49 66 9 50

Median

0.2 (0.05-0.6) 0.22

Many UK

3, 36 40

~

0.2

Median

0.001

UK

mg X day-'

Many UK Germany Japan Korea India USA

3300

Median

40

3 40 31 70 49 52 9.35

La 0.13 (0.0 I 1-0.85) 0.006

Germany Sweden

37 38

Li

0.11 (0.1 2

UK India USA

40 52 3. 36

O.l?

Median

Mg 340(160-410) 480-960 250 740 240 I40400

Mn 3.7 (2.2-9) 1.3-3.2 calc. 2.1 4.6 2.7 (1.4-5.2) 2.6 8.7 (2.3-10) 6.8 8.3 2.9 0.8-7. I (0.4-5 0.7-7 1-3.5 2.9--4.1 4 M o 0.3 0.13 0.07 (0,005- I ) 0.22-0.6 0.12-0.24 0.1

0.2 N a 4400 (200-27000) 4600 4500 (1900-8200) 6700 25 00-4500 4200-7200

4500 Nb 0.02

Ir

Country

3300 (1400-6500) 2800 2400 (1200-4 100) 1600 2100 4 100 34004800

400

Median

G e 0.37

X K

10

~~

16

I

R eJ

Country

C U 35 (0.7-5) 1.6-3.4 1.5-3.1 2.7 (0.6--12.3) 2.4-3.7 0.85-1.3 1.3-4.3 3.6 2.5 5.8 2.4 2.2 3 0.76-1.7 (0.3-0.6

0.62

Many Many UK India Canada USA

3,36 87 40,7l 52 88 9, 35. 55.89

Median Many Many UK UK Germany Italy Japan Korea India NZ NZ USA USA USA Canada

3, 36 10 40 90 37

51 13.46 49 52 68 91 13 9,35 32.64 66.92,93

Median Many UK Germany Sweden USA USA

3. 36 40 37 38.43 94 34

Median Many UK Germany India USA USA

3. 36 40 37 52 9 35

Median UK USA

40 95

The Elemental Content of Human Diets and Excreta

X

mg X day-'

Ni 0.4(0.2-0.6) 0.17 (0.3 0.3 (0.3-0.5 0.4

R ec

Counrrv

USA USA UK Russia Italy

3 96 40 65 39.42

UK

40

P

1590 1260-2450 1200-2000

Many UK India Canada USA USA

3. 34 40 52 53 54 3s

I400

Median

0.44 (0.15-0.44) 0.32 0.55 0.35-0.5 0.12 0. IS (0.09-0.18)

IS00

Pb

0.06

Many UK Italy Russia Germany Japan Canada USA

0.3

Median

UK

40

UK Germany Italy Sweden Japan India USA

40 37 39.42 38.43 70 52 3. 36

0.11

Pt

Rb 4.35 1.9 (0.7-3.2) 4.1 (0.5-21) 2-5 1.6 2.7 1.5-2.7 2

3. 36 40 51 51 97 46,98 66 50

'

Many 3. 36 Many 10 UK 40 UK 99 Germany 37 Italy 39.42. 84 Sweden 38.43 Egypt 67 Japan 100 China 101 NZ 102 NZ 103 NZ 1040 Venezuela 1046 USA 9. SO. 105 USA (Dakota) 86h 106 Canada

0.15

Median

18? 22-46 I200?

Many USA UK

3 55 40

Germany

37

0.19 0.94 (0.33-1.4) 4 (1-40)

UK Italy USA

40. 1070 107h 3. 34. 36

I '!

Median

0.86 4 1.9 (1.3-2.2) 0.36- I .Y

UK India USA USA

I .5

Median

Sm 0.013 (<0.0010.08)

Sr

ReJ

Couniri,

0.15 (0.05-0.35) 0 . 1 6 - 0 . 3 calc. 0.2 0.06 0.059 ( 0 . 0 0 9 4 . 1 7 ) 0.023 (0.003-0.064) 0.12-0.14 0.029 (0.003-0.37) GO. I5 0.03 0.006-0.07 0.028 0.56 0.33 0 . 1 3 4 . I5 0.22 0.2 (0.1-0.22)

40 52 3. 34. 36 35

Median UK

40

S

850(800-930) 940 1200

Many UK India

3 40 52

900

Median

sc

Si

Sn

Re <0.001

Sb 0.05 0.034 0.023 (0.005-0.074) 0.0016 (0.000080.009) 0.008-0.065 0.4-0.87

Se

Median

0 s <0.001 1400(600-2800) 1900

mgXday

X

75

Estimate UK Germany Italy

3 40 37 39.42

Sweden USA

38.43 32

0.0 I5?

Median

0.001 0.000 15 (0.000030.003) 0.00004-0.0005

Germany Italy

37 39,42

Sweden

38-43

0.000 I

Median

Ta 0.001

UK

40

Te 0.6 0.I 1

USA USA

3 36

UK USA

40. 108

0.8 0.85 (0.1-3) 0.3Y

UK USA USA

40 3. 36 34

0.8

Median

0.0015 (0.002

Many UK

40

0.0019 0.001 0.013-0.3 0.0015-0.0045 0.00 13

Many UK Russia Japan USA

3 40. 109 7 110. I l l 112

0.0015

Median

Th

Ti

TI

u

3

3

76

Environmental Chemistry

X v

w

Y

mg X d a y - '

Countrv

R el:

X

mgXday-l

3.36 96 I07

Zn

13(10--15) 4.6-21 calc. 9.1-14 7.6-10 6-40 12 (4.2-25) 77 (2.3- 17)

Many Many UK W . Scotland Europe Germany Italy

6-15 9-16 6-36 II 8.9 (1.6-25) 9.7 5-22.5

Sweden Russia Asia Japan India NZ Mexico USA

11-18

USA

12-20

Canada

13

Median

0.053 4.2(1-6)

UK USA

2 0.02 0.01 (0.008-0.012)

Many USA Italy

0.0 1

Median

<0.001 0.01 (<0.0050.034) 0.0 I

UK Germany

40 37

Sweden

38,43

0.01?

Median

0.016

UK

16

40

Zr

*

=

R eJ:

Countrv

3,36 10

40. 71 113 13 37 39,42,57. 114 38,43 13 13 46 52 68 115

13,32,7375 9, 31, 50. 64. 116-1 18 66, 119

40 3

intake in food alone, not including drink. calc. : calculated.

Table 2 Elemental content of 24 hour urine samples from adults X

R eJ:

Cauntry

rng Xday-I

Ag 0.009 (0.0006-0.0 I ) Many (0.003 Italy 0.0054.00 1 Sweden 0.00 16 USA

0.00 1

Median

0.1 0.57-0.8

Many USA

0.1?

Median

As 0.05 0.009-1.2 0.022- 1.6 0.0065-0.6

Many Scotland Belgium Sweden

3.34 42 38, 120. 121 122

X rng X d a y - ' Be 0.001 <0.0002 < 0.00007

Bi Al

0.047

USA

0.05

Median

AU 0.0000010.000 08

B

Sweden

0.00004?

Median

1 0.57-

Many USA

1.1

3, 36 34. 123

3 44 31 38.43, 120. 121. 124, I25 126

38,43. 120, 121, 125

3,36 34. 123

Median

I ~~

Ba 0.05 (0.007-0.56) 0.014 (0.008--0,039) 0.052 0.027 0.025

Many UK Sweden USA Median

3. 34 127, 128 125 I23

R eJ 3,36 129 130

Cauntr,v Many Germany USA

<0.000 1

Median

0.016(<0.000.0024)

USA

131

7 (0.8-122) 3.5-10.5 3.8 I .5-7

Many Belgium France Sweden

3-8

Japan

3,36 31 132 38,43, 120. 121 133

~~~

Br

~~~~~

4 C a 180 130-340 140-240 140-200 2 1 1 (145-460) C d 0.1 0.0059 0.015 0.00 1 0.001-0.005

~

-

~~

~

-

Median Many UK Belgium USA

3 128 31 34

Mean

41

Many UK Germany Germany Sweden

3 I34 I29 135 38.43, 120. 121 136 59 137 36,64 61 138

0.00025-0.0004 0.003 0.000 1 5 4 . 0 0 2 0.0 14-0.03 0.00 1 0.005

Sweden Japan USA USA USA USA

0.00 I ?

Median

77

The Elemental Content of Human Diets and Excreta Cou n I ry

R eJ

Ce 0.0015-0.036

Sweden

46. 121

CI

4400 (2200--13000) 2900-1 1000 4 700-6500

Many Belgium Switzerland

3 31 139

4400

Median

0.2 0.000 75 0.0005-0.0027 0.002 (0.00030.016) 0.0005-0.0038

Many

0.00 18 0.0 1 0.0044

USA USA USA

0.00 1

Median

X

co

mg X day-'

Cr 0.07 0.0006 0.0006-0.001 2 t0.005 0.0022-0.0037 0.0034.027 0.01 1 0.001 1 0.0074.009 0.018

0.00 I

UK Belgium Italy Sweden

Many

UK Belgium Italy Finland Sweden Turkey

USA USA USA

X

3, 34, 36 140 31 39,42 38,43. 120. 125 131 141 142

3 140 31 39 143, 144 43, 125 145 146, 147 36, 148~1,149 141

I

K

Country

0.0074.026 0.0014

USA USA

0.004

Median

0.17 (0.009-1.3) 0.096-0.92 0.05 0.15-0.36 0.13-0.25 0.15-1. I 0.34.38

Many Belgium Finland Japan

0.17

Median

2800 (1 100-4900) 2500 1800-5900 1800-2200

Many

2800

Median

La 0 . 0 0 0 2 8 4 . 0 0 0 9

Ref.

Many Belgium Germany ltaly ltaly Sweden

3. 36 31 155 84 39.42 38,43, 120. 125 156~1,b 1S7n

3,36, 1576 31 158 150 149, 159 160 141. 161

USA USA USA

3 162 31 139

UK Belgium Switzerland

Sweden

38, 120, 125

UK

USA

163 3.36

Many Many USA

3 87 164a

Median Li

Cs 0.009 0.0067-0.02 0.052 (0.005-0.33) 0.014.05

0.0 I

Many Belgium ltaly Sweden

3 3I 39,42 38,43, 120, 121, 125

-

Belgium Sweden

3.36 64, 1486 31 38.43, 120

0.049

Mean

41

l(0.214.5) 3.1 0.8 1 0.45-20

Many Japan

3, 36 150 151 152

1.7

Median

Fe 0.25 ( 0 . 0 8 4 . 3 2 ) 0.092-0.2 (0.2 0.134.3 1

Many

USA

USA USA

Many Czech. Italy Sweden

0.014

USA

0.2

Median

0.69 0.8

Mg 130(60--1670) 200- 1200 246

Median

Cu 0.05 0.022 0.0115-0.034 003 54.05

F

rng Xday-'

Hg 0.0005-0.09 0.0023-0.01 1 0.0043 0.0037 <0.002-0.022 0.00 1-0.003

114(60--154)

41 ~~

Mn 0.03 (0.0 1 4 . 3 4 ) 0 . 0 0 0 0 9 - O . ~ 067 0.0 13 0.0014.006 0.0124.016 0.00009-0.0029 0.0004?

M o 0.15 (0.01---0.94) 0.3 0.081-0.2 0.049

3,36 153 39,42 39,43, 120, 121, 125 138

Mean

0.061 ( 0 . 0 4 9 4 . 1 5 ) Na 3300 (1400-7800) 4000 2 100-8400 2900-4600

Many Belgium Israel

USA USA USA

3, 1646 3I 165 166- 168 64, 141 169

Median Many Belgium Sweden

USA

3, 36 170 38,43, 120 13 1

Mean

41

Many

3 162 31 139

UK Belgium Switzerland

-

G a 0.042

Russia ~

Ge 1.4

154

3 300

Median

~~

USA

3

N b 0.36

USA

95

78 X Ni

Environmental Chemistry mg X day-'

R eJ:

X

3.36 171 39.42 172-17s 176 122. 141. 177

Si

Coun~rj,

0.01 I(0.0014-0.33) 0.0009

t0.08

Many Holland Italy

0.0024-0.0052 0.0067 0.0 12-0.02

USA USA USA ~~

0.01? P

Many

9 00

Median

Pb 0.045 (0.01-0.08) 0.018 0.062 0.007-0.03 1 0.0764.09 (0.03

0.047 R b 1.9 1.1--4 1.5-2.4

S

Sb

sc

UK USA USA

Srn 0.00 1-0.0028

Sweden

38. 121. 125

Sn

0.02 (0.0007-1. 1 ) 0.026 (0.004--0.058) 0. I 0.0 17-0.026

Many

3, 36

USA USA USA

34 122, 131

0.02

Median

0.34 (0.24-0.44) 0.14-0.36

USA UK

3. 34 128

Many

0.24 (0.11-0.39)

Mean

41

0.053?

USA

185

Yugoslavia

186 3 187

Sr

3.36 I3 I I38 137 I79 I80

Mean

41

Many Belgium Sweden

3 3I 38.43, 120. 121. 125 39.42 36. 181

3 . I (0.5-9) I . 1-2.3

USA

1.5

Median

800 (270-2600) 1320

Many Switzerland

800

Median

<0.0003 0.001-4.01 1

Italy Sweden

39. 42 38.43. 120. 121

0.04

USA

3

Italy

Median

<0.00001

<0.0000050.00008 0.000 52-0.00057

Italy Sweden

39.42 38.43

Sweden

120. 125

0.00004:'

Median Many Belgium Belgium Italy

3. 36 31 182 39,42. 84

Sweden

38. 43. 120. 121 103 183

0.0 13 0.02

NZ

0.05

Median

USA

Te

Th 0.00011 0.000 1 0.000002 8

184

USA USA

0.33 0.43

USA

3, 36 34

TI

0.0002--0.0008

Germany

188

U

<0.0005 t0.00045 0.00046 0.000 34 0.000 14 (0.000060.0003)

Many Germany Yugoslavia India

3

0.0003

Median

0.015 <0.0002 0.0084.046

Many Yugoslavia

3, 36

USA

192

t0.0002

Best value

0.0002-0.02

Sweden

0.007

Median

Ti

3 140

0.002?

Se 0.05 (0.002-0.99) 0.02-0.09 0.15-0.24 0.013 (0.00230.075) 0.025-0.07

3

3 I28 34 I78

USA USA USA USA USA

R eJ

Coiinrry

Many

Median

900 470- 1390 I200 540

mg X day-' lO(4.2--15)

V

w

Many

Zn 0.5 0.0864.75 0.47 (0.077-1.2) 0.3-1 0.14-0.4 1 0.14-0.78

USA

Zr

0.15

19 1

38. 43, 120, 121. 125

Many Belgium Italy Sweden

3 . 36 31 39.42 38.43. 120 I3 I. 165 193.64

USA USA

~~~

0.44 (0.042-

189 186 190 112

~~

I .25)

Mean

41

USA

I94

The Elemental Content of Human Diets and Excreta

79

R. Cornelis, A. Speecke, and J . Hoste, Anal. Chim. Acta, 1975, 78, 317. G. K. Murthy, U. Rhea, and J . T. Peeler, Environ. Sci. Technol., 1971, 5,436. 3 3 G . D. Christian, Fortschr. Chem. Forsch., 1972, 26,77. ” 32

I. H. Tipton, P. L. Stewart, and P. G. Martin, Health Phys., 1966, 12, 1683. A. Gormican, J . Am. Diet. Assoc., 1970, 56, 397. 36 H. A. Schroeder and A. P. Nason, Clin. Chem., 1971, 17,461. ” R. Schelenz, J . Radioanal. Chem., 1977, 37, 539. 3n P. 0. Wester, Acta Med. Scand., 1971, 190, 155. 39 G . F. Clemente, J . Radioanal. Chem., 1976, 32, 25. 4n E. I. Hamilton and M. J. Minski, Sci. Total Environ., 1973, 1, 375. 4 1 G. V. Iyengar, W. E. Kollmer, and H. J. M. Bowen, ‘The Elemental Composition of Human Tissues and Body Fluids’, Verlag Chemie, Weinheim and New York, 1978. 4 2 G. F. Clemente, L. C . Rossi, and G . P. Santaroni, J . Radioanal. Chem., 1977, 37, 549. 4 3 P. 0. Wester, Atherosclerosis, 1974, 20, 207. 44 J . D. Cross, I. M. Dale, H. Smith, and L. B. Smith, Radiochem. Radioanal. Lett., 1978, 34, 345. “ H. Woidich and W. Pfannhauser, Deufsch. Lebensmitt. Rundsch., 1979, 75, 190. 46 S. Horiguchi, K. Teramoto, T. Kurono, and K. Ninemiya, Osaka City Med. J., 1978, 24, 13 1. 4’ M. Nakao, Osaka Shiritsu Daigaku Igaku Zasshi, 1960,9, 541. 48 M. Ishizaki, Nippon Eiseigaku Zasshi, 1979, 34, 605. 49 C. Lee, N. B. Kim, and I. C. Lee, J. Korean Nucl. SOC.,1976,8, 195. K. R. Mahaffey, Environ. Health Perspect., 1975, 12. 63. M. G . Kolomiitseva, Gig. Pitan., 1966, 121. ” S. D. Soman, V. K. Panday, K. T. Joseph, and S. J . Raut, Health Phys., 1969, 17,35. 53 U. S. Srivastava, A. K. Rakshit, and I. Khare, Nutr. Rep. Int., 1978, 18, 313. 5 4 W. H. Moon, J. L. Malzer, and H. E. Clark, J . A m . Diet. Assoc., 1974, 64, 386. 5 5 J. L. Kelsay, K. M. Behall, and E. S. Prather, Am. J . Clin. Nutr., 1979, 32, 1876. 5 6 W. Raffke, in ‘Kadmium Symposium 1977’, ed. F. Bolck, Jena, 1979, p. 217. ” G. Santoprete, Riv. Merceol., 1979, 18, 149. 5 8 R. Rantu and A. Sporn, Nahrung, 1970, 14, 25. 5 9 S. Kojima, Y. Haga, T. Kurihara, T. Yamawaki, and T. Kjellstrom, Enoiron. Res., 1977, 14, 436. 6o N. Yamagata and I. Shigematsu, Bull. Inst. Publ. Health, 1970, 9, 1. 6 1 N. E. Kowal, D. E. Johnson, D. F. Kraemer, and H. R. Pahren, J . Toxicol. Environ. Health, 1979, 5, 995. 6 2 J. S. Drury and A. S. Hammons, Report ORNL/EIS-149, 1979. 63 B. Harland, P. Corneliussen, L. Prosky, and J. E. Vanderveen, in ‘Kadmium Symposium 1977’, ed. F. Bolck, Jena, 1979, p. 215. 6 4 H. Spencer, C. R. Asmussen, R. B. Holtzman, and L. Kramer, Am. J . Clin. Nutr., 1979, 32, 1867. ” P. I. Nodiya, Gig. Sanit., 1972, 37, 108. 66 J. C. Meranger and D. C. Smith, Can. J . Publ. Health, 1972,63, 53. 67 V. Maxia, S. Meloni, M. A. Rollier, A. Brandone, V. N. Patwardhan, C . I. Waslien, and S. El Shami, in ‘Nuclear Activation Techniques in the Life Sciences’, IAEA, Vienna, 1972, p. 527. 6R B. E. Guthrie, Proc. Univ. Otago Med. Sch., 1973, 51,47; Proc. Nutr. SOC.N Z , 1977, 2, 39. 69 R. A. Levine, D. H. P. Streeten, and R. J. Doisy,Meiab. Clin. Exper., 1968, 17, 114. 7fl N. Yamagata, Nature (London), 1962, 196.83. ’I J. A. Spring, J. Robertson, and D. H . Buss, Br. J . Nutr., 1979,41,487. 7 2 P. Orlando, F. Perdelli, J. Franco, and A. Pietrini-Pallotta, G. Ig. Med. Prev., 1976, 17, 70. 7 3 D. B. Milne, D. D. Schnakenberg, H. L. Johnson. and G . L. Kuhl, J . Am. Diet. Assoc., 1980, 76,4 1. 74 L. M. Klevay, S. J. Reck, and D. F. Barcome, J . Am. Med. Assoc., 1979, 241, 1916. ” J. M. Holden, W. R. Wolf, and W. Mertz, J . A m . Diet. Assoc., 1979, 75, 23. “ J . Longwell, R. SOC.Health J., 1957, 77, 361. 7 7 H. A. Cook, Lancet. 1969, 2, 329. 7 8 R. D. Gabovich, Gig. Pifan.. 1966, 69. l9 T. Okamura and T. Matsuhisa, J . Jpn. Soc. Food Nutr.. 1968, 21, 236. 8fl L. Singer, R. H. Ophaug, and B. F. Harland, Am. J . Clin. Nutr., 1980, 33, 328. J. R. Marier and D. Rose, J . Food Sci.. 1966. 31. 94 1. D. C. Abbott and J. 0%.Tatton, Pestic. Sci., 1970, 1. 99. 83 J. D. Cross, I. M. Dale. H. Smith, and L. B. Smith, J . Radioanal. Chem., 1979, 48, 159. 84 L. C. Rossi, G. F. Clemente, and G. Santaroni, Arch. Enoiron. Health, 1976. 31, 160. 85 0. I. Joenssuu et al., V i r . Foda., 1974. 24, 59. u6u A. Fouassin and M. Fondu, Arch. Belg. Med. SOC.Hyg. Med. Trav. Med. Leg., 1978, 36,48 1 866 0. E. Olson and 1. S. Palmer, Proc. S. Dak. Acad. Sci., 1978, 57, 113. 87 J. K. Aikawa, in ref. 1, Vol. 2, p. 47. 8R U. S. Srivastava, M. H. Nadeau, and L. Gueneau, Nutr. Rep. Int., 1978, 18, 235. R9 R. Schwartz, H. Spencer, and R. A. Wentworth. Clin. Chim. Acfa, 1978, 87, 265. 34

35

*’

80

Environmental Chemistry

’” R. W. Wenlock, D. H. Buss, and E. J. Dixon, Br. J . Nufr., 1979,41, 253. B. E. Guthrie and M. F. Robinson, Br. J . Nutr., 1977. 38, 5 5 . D. C. Kirkpatrick and D. E. Coffin, Can. J . Publ. Health, 1977,68, 162. 9 3 U. S. Srivastava, M. H. Nadeau, and N. Carbonneau, Nutr. Rep. Znt., 1978, 18, 325. 94 T. A. Tsongas, R. R. Meglen, P. A. Walravens, and W. R. Chappell, Am. J . Clin. Nutr., 1980, 33, 1103. 95 H. A. Schroeder and J. J. Balassa, J . Chron. Dis., 1965, 18, 229. 9 6 D .R. Myron, T. J . Zimmerman, T. R. Shuler, L. M. Klevay, D. E. Lee, and F. H. Nielsen, Am. J . Clin. Nutr., 1978, 31, 527. 97 B. Boppel, Z . Lebensm. Unters. Forsch., 1975, 158,287. 9n Y. Imamura, Osaka City Med. J., 1967, 3, 167. 99 J. Thorn, J. Robertson, D. H. Buss, and N. G. Bunton, Br. J . Nutr., 1978, 39, 391. loo H. Sakurai and K. Tsuchiya, Environ. Physiol. Biochem., 1975, 5, 107. l o l Keshan disease research group, Chin. Med. J., 1979,92,471 and 477. Io2 N. M. Griffiths, Proc. Univ. Otago Med. Sch., 1973, 51, 8. lo’ C. D. Thomson and M. F. Robinson, Am. J . Clin. Nutr., 1980, 33,303. J. H. Watkinson, N Z M e d . J., 1974, 80, 202. 104bM. C. Mondragon and W. G. Jaffe, Arch. Latinoam. Nutr., 1976,26,343. Io5 V. C. Morris and 0. A. Levander,J. Nutr., 1970, 100, 1383. Io6 J. N. Thompson, P. Erdody, and D. C. Smith, J . Nutr., 1975, 105, 274. E. I. Hamilton, M. J. Minski, J. J. Cleary, and V. S. Halsey, Sci. Total Environ., 1972, 1, 205. A. R. Byrne and L. Kosta, Sci. Total Environ., 1979, 13, 87. Io8 R. J. Clifton, M. Farrow, and E. I. Hamilton, Ann. Occup. Hyg., 1971, 14, 303. Io9 E. I. Hamilton, Health Phys., 1972, 22, 149. ‘lo T. Nozaki, M. Ichikawa, T. Sasuga, and M. Inarida, J . Radioanal. Chem., 1970, 6, 33. Il1T. Yamamoto, E. Yunoki, M. Yamakawa, M. Shimizu, and K. Nukada, J . Radiat. Res., 1974, 15, 156. G. A. Welford and R. Baird, Health Phys., 1967, 13, 1321. T. D. B. Lyon, H. Smith, and L. B. Smith, Br. J . Nutr., 1979,42,413. ‘14 P. Orlando, F. Perdelli, J. Franco, and A. Pietrina-Pallotta, G. Ig. Med. Prev., 1976, 17, 79. I ” I. F. Hunt, N. J. Murphy, J. Gomez, and J. C. Smith, Am. J . Clin. Nutr., 1979, 32, 15 11. E. D. Brown, M. A. McGuckin, M. Wilson, and J. C. Smith, J . Am. Diet. Assoc., 1976, 69,632. ‘ I 7 D. Osis, L. Kramer, E. Wiatrowski, and H. Spencer, Am. J . Clin. Nutr., 1972, 25, 582. H. S. White, J. Am. Diet. ASSOC.,1976, 68, 243. U. S. Srivastava, M. H. Nadeau, and N. Carbonneau, J . Can. Diet Assoc., 1977, 38, 302. I Z 0 P. 0. Wester, Acfa Med. Scand., 1973, 194, 505. Iz1 H. Bostrom and P. 0. Wester, Acta Endocrinol., 1969,60, 380. 1 2 * H. M. Perry and E. F. Perry, J . Clin. Invest., 1959, 38, 1452. Iz3 I. H. Tipton, P. L. Stewart, and J. Dickson, Health Phys., 1969, 16,455. 124 D. Brune, K. Samsahl, and P. 0. Wester, Clin. Chim. Acta, 1966, 13, 285. 125 H. Bostrom and P. 0. Wester, Acta Med. Scand., 1968, 183,209. 126 S. L. Wagner, P. Weswig, and C. Ore, Arch. Environ. Health, 1974, 28, 77. 12’ G. E. Harrison and W. H. A. Raymond, J . Nucl. Energy, 1955, 1, 290. 12’ T. E. F. Carr and A. Sutton, in ‘Neutron Activation Analysis in the Life Sciences’, IAEA, Vienna, 1976, p. 445. I Z 9 R. Barchet, J. Biermann, M. Feucht, T. Haag, H. Jori, and G. Wilk, Deutsch. Lebensmitt. Rundschau, 1972,68, 69. I 3 O D. C. Sutton, U.S. Atomic Energy Commission Rep. HASL 134, 1963. I 3 I L. E. Meltzer, J. Rutman, P. George, R. Rutman, and J. R. Mitchell, Am. J . Med. Sci., 1962, 244, 83. 132 H. Sklavanitis and D. Comar, in ‘Neutron Activation Analysis in the Life Sciences’, IAEA, Vienna, 1967, p. 435. 1 3 3 S . Ohno, Analyst (London), 1971,96,423. 134 G. S. Fell, J. M. Ottoway, F. E. R. Hussein, R. G . Michel, and M. L. Hall, in ‘Clinical Chemistry and Clinical Toxicology of Metals’, ed. S. S. Brown, Elsevier, Amsterdam, 1977, p. 367. 13’ G. Lehnert, K. H. Schaller, and T. Haas, Z . Klin. Chem. Klin. Biochem., 1968, 6 , 174. 136 C. G. Elinder, T. Kjellstrom, T. Linnman, and G. Pershagen, Environ. Res., 1978, 15,473. P. A. Legotte, W. C. Rosa, and D. C. Sutton, Talanta, 1980, 27,39. J. S. Elliot and M. E. Ribeiro, Invest. Urol., 1973, 10,253. 1 3 9 Documenty Geigy, 7th Ed., Geigy AG, Basle, 1968. 140 R. F. Coleman, J. Herrington, and J. T. Scales, Br. Med. J., 1973, 1, 157. 141 C . F. Consolazio, R. A. Nelson, L. 0. Matoush, R. C. Huges, and P. Urone, U.S. Army Med. Res. Nutr. Lab. Rep. 284, 1, 1964. 142 M. J. Harp and F. I. Scoular, J. Nutr., 1952, 41,67. 91

y2

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S. Punsar. W. Wolf, W. Mertz, and M. J. Karvonen, Ann. Clin. Res., 1977, 9. 79. J. Kumpulainen, Anal. Chim. Acta, 1980, 113. 355. 145 C. T. Gurson and G. Saner, Am. J. Clin. Nutr., 1978, 31, 1162. 146 K. Beyermann, H. J. Rose, and R. P. Christian, Anal. Chim. Acta, 1969. 45, 5 I . 147 M. W. Routh, Anal. Chem., 1980, 52, 182. 148a F. W. Mitman, W. R. Wolf, J. L. Kelsay, and E. S. Prather, J. Nutr., 1975, 105, 64. 148b C. J. Gubler, H. Brown, H. Markowitz, G . E. Cartwright, and M. M. Wintrobe, J . Clin. Invest., 1957, 36, 1208. 149 K. M. Hambridge, Anal. Chem., 1971, 43, 103. IJ0S. Ohno, M. Suzuki, K. Sasajima, and S. Iwata, Analyst (London), 1970, 95, 260. lS1 M. Vandeputte, J. De Cock, L. Dryon, A. Vercruysse, F. Alexander, and D. L. Massart, Clin. Chim. Acta, 1977, 75,205. I s 2 J. D. Neefus, J. Cholak, and B. E. Saltzman, Am. Ind. Hyg. Ass. J . , 1970, 31,96. 1 5 3 M. Brodanova and V. Hoenig, Scand, J . Gastroenterol., 1968, 1, 167. lJ4 E. S. Belozerov, Bull. Exper. Biol. Med., 1966,62, 114 1. 155 K. M. Schaller, P. Strasser, R. Woitowitz, and D. Szadkowski, 2. Anal. Chem., 1971, 256, 123. K. J. Rohm and W. C. Purdy, Anal. Chim. Acta, 1974, 72, 177. 0. S . Gibbs, J . Pharmacol. Exper. Therup., 194 1, 72, 16. 157u N. P. Kubasik, H. E. Sine, and M. T. Volosin, Clin. Chem., 1972, 18, 1326. 157b M. Heurtebise and W. J. Ross, Anal. Chem., 1971, 43, 1438. IJ8 B. A. Lamberg, P. Wahlberg, 0. Wegelius, G. Hellstrom, and P. I. Forsius, J. Clin. Endocrinol., 1958, 18,991. IJ9 M. Bruger, J. W. Hinton, and W. F. Lough, J . Lab. Clin. Med., 1941, 26, 1942. I6O A. J. Blotcky, D. M. Duven, N. M. Grauer, and E. P. Rack, Anal. Chem., 1974, 46,838. 1 6 1 D. A. Fisher and T. H. Oddie, J. Clin. Endocrinol., 1964, 24, 1143. 162 S. G. Welshman and M. G. McGeown, Br. J . Urol., 1975,47,237. 163N . L. Kent and R. A. McCance, Biochent. J., 1941,35,837. 143

144

C. K. Kim and W. W. Meinke, in ‘Modern Trends in Activation Analysis’, College Station, Texas, 1965, p. 316. 164b H . A. Schroeder, J. J. Balassa, and I. H. Tipton, J . Chron. Dis.,1966, 19,545. 165 B. Moav, Int. J . Appl. Radial. Isot., 1965, 16,365. 166 D. G. Van Ormer and W. C. Purdy, Anal. Chim. Acta, 1973,65,93. E. A. Levri and C. N. Angel, Trace Subst. Environ. Health, 1968,4, 207. 168E.D. Bird, W. H. Ellis, and W. C. Thomas, in ‘Modern Trends in Activation Analysis’, College Station, Texas, 1965, p. 216. 169E.L. Kanabrocki, L. F. Case, T. Fields, L. Graham, E. B. Miller, Y. T. Oester, and E. Kaplan, J. Nucl. Med., 1965, 6, 780. G. D. Christian and G. J. Patriarche,Anal. Lett., 1979, 12, 1 1 . D. Spruit and P. M. Bongaarts, in ‘Clinical Chemistry and Clinical Toxicology of Metals’, ed. S. S. Brown, Elsevier, Amsterdam, 1977, p. 261. 172 M. D . McNeely, M. W. Nechay, and F. W. Sunderman, Clin. Chem., 1972, 18,992, 1 7 3 S. Nomoto and F. W. Sunderman, Clin. Chem., 1970, 16,477. 174 E. J. Bernacki, G. E. Parsons, B. R. Roy, M. Mikac-Devic, C. D. Kennedy, and F. W. Sunderman, Ann. Clin. Lab. Sci., 1978, 8, 184. 1 7 3 D. Mikac-Devic, F. W. Sunderman, and S. Nomoto, Clin. Chem., 1977, 23, 948. 176 I. Andersen, W. Torjussen, and H. Zachariasen, Clin. Chem., 1978, 24, 1198 177 F. W. Sunderman, Am. J . Clin. Pathol., 1965, 44, 182. 178 B. S. Walker, J . Lab. Clin. Med., 1932, 17, 347. G. A. Rechnitz and N. C. Kenny, Anal. Lett., 1970, 3,259. P. A. Pleban and K. H. Pearson, Anal. Lett., 1979, 12,935. 181 0. L. Wood, Biochem. Med., 1970, 3,458. Is2 G. J. Patriarche, Anal. Lett., 1972, 5,45. IB3 W. J. R. Camp and V. A. Cant, Fed. Proc., 1949,8, 219. Ig4 L. L. Nunnelley, W. R. Smythe, A. C. Alfrey, and L. S. Isbels, J. Lab. Clin. Med.. 1978, 91, 72. lS5 H. A. Schroeder, J. Buckman, and J. J. Balassa, J . Chron. Dis.,1967, 20, 147 and erratum. Is6 M. Picer and P. Strohal, Anal. Chim. Acta, 1968,40, 131. B. L. Twitty and M. W. Boback, Anal. Chim. Acta, 1970,49, 19. E. Weinig and P. Zink, Arch. Toxikol., 1967, 22, 255. IE9 K. Irlweck and S. Streit, Mikrochim. Acta, 1972, 2, 63. lgo A. K. Ganguly, IAEA Tech. Rep.-I 18, Vienna, 1970. 191 A. R. Byrne and L. Kosta, Sci. Total Environ., 1978, 10, 17. 192 G. D. Christian,Anal. Lett., 1971, 4, 187. 193 S. Meret and R. I. Henkin, Clin. Chem., 1971, 17, 369. 194 H. A. Schroeder and J. J. Balassa, J . Chron. Dis.,1966, 19, 573.

164u

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but less readily from working subjects. Suitable containers and precautions with Quantitative collection regard to storage of urine are discussed by Cornelis et of faeces is notably difficult and is usually only attempted in balance studies by dedicated volunteers. The total elemental analysis of whole diets and urine is not yet feasible, though most of the elements can be determined by such techniques as atomic absorption emission s p e c t r ~ m e t r y , ~neutron ~ - ~ ~ activation9*3 1 * 3 7 - 3 9 and s p e c t r ~ m e t r y3 ,3 ~ ~ ~ spark-source mass s p e ~ t r o m e t r y Most . ~ ~ of the lanthanides, the platinum metals, and Ga, Hf, In, Re, Ta, and Y have never been satisfactorily determined in diets or urine. Technically speaking, the analysis of these matrices is difficult because of the very small masses of the elements sought, and because of the large number of interfering substances present. Hence it is not surprising that disagreements still arise in the literature. While agreement between analytical techniques is fairly good for some elements, the discussion below indicates that major discrepancies in published figures remain for Ag, Bi, Cd, Co, Cr, Li, Nb, Sb, Th, V, and Zr in diets and for Ag, As, Ba, Be, Cd, Co, Cr, Mn, Ni, Sb, Sn, Th, and V in urine. Tables I and 2 give a selection of recent data for the elemental contents of diets and urine in mg day-’; some of the data is taken from earlier review^.^,^^ An attempt has been made to pick out best values and normal ranges for many elements, and to compare these with the values recommended in the compilation by Snyder,3 whose results are strongly influenced by an earlier review due to Schroeder and N a ~ o n Significant .~~ differences will be noticed for several rare elements. In view of the uncertainties, suggested values for urinary excretion as a percentage of dietary intake are mostly provisional. The data in Tables 1 and 2 form a basis for the discussion below, in which the elements are subdivided according to their position in the periodic table.

4 Inputs, Outputs, Deficient Concentrations, and Oral Toxicities of the Elements Group IA: Li, Na, K, Rb, Cs.-The analytical data for the alkali metals, apart from lithium, are reasonably consistent. Sodium and potassium are two of the most common elements in the diet, and are also essential. The other three metals are much rarer and are probably inessential. The variation in sodium and potassium intake with age has been r e ~ i e w e d Sodium .~ is more variable in the diet than is potassium, because of differences in salt addiction. All the metals are well absorbed and 75-85% of the intake is excreted in urine; losses in perspiration are highly variable. Some faecal excretion of potassium occurs by loss through the colon into the b0we1s.l~~ Sodium and potassium deficiency have not proved to occur in human populations (excessive loss of salts through sweating may cause cramps, but could be a chloride deficiency symptom). Extrapolation from animal diets suggests that less than 45 mg Na day-’ or 70 mg K day-’ in the diet could be harmful. With g potassium ions (as KCI) or 230 g respect to toxicity, an oral dose of 8.5-14 sodium (as NaCl) are considered to be letha1.22-’96In view of its emetic properties, 19’

G. Wiseman, ‘Absorption from the Intestine’, Academic Press. London, 1964. E. M. Boyd. ‘Toxicity of Pure Foods’, Chem. Rubber Co., Cleveland, Ohio. 1975.

The Elemental Content of Human Diets and Excreta

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oral poisoning by common salt is very unlikely. Miller considers that sodium intake should be between 2 and 10 g Na day-'.I9' Lithium toxicity is of some importance in view of the use of this ion in treating schizophrenics. 90-200 mg Li day-' can be tolerated without toxic symptoms, but acute doses of 650-800 mg Li lead to poisoning.22 Rubidium and caesium have about the same toxicity to rats as has

Group IB: Cu, Ag, Au.-Dietary copper has often been measured since the metal was proved to be essential, and is ingested at an average rate of 2.5 mg Cu day-'. Lower values have been found in hospital diets35 and have not given rise to deficiency symptoms, which have been noted in children on very poor diets.lY8 Urinary excretion is about 2% of the dietary intake, but 32-60% of dietary copper ~ that biliary excretion takes place. Chemical is said to be a b ~ o r b e d ,suggesting forms of copper in common foods are not known, but free copper(I1) ions are unlikely to be present in either foods or natural waters.IgYUnderwood has reviewed those dietary constituents known to affect copper absorption. Cases of copper sulphate poisoning suggest that the acute lethal dose of copper(I1) ions by mouth is 7.5 g cu.22 Dietary silver is either highly variable or subject to analytical errors. Recent work suggests that both dietary input and urinary output are lower than the values given by Snyder.3 Values probably differ in individuals using silver cutlery from those using other materials. The percentage absorption is uncertain, but should be quite high for Ag' cations. Silver is not known to be essential, but is mildly toxic, causing symptoms of argyrosis when acute doses of more than 60 mg Ag are ingested. 1.3-19 g Ag' is said to be lethal to man.200 Dietary gold is very small but measurable by neutron activation, and is of the order of 10-100 ng Au day-'. Metallic gold can be absorbed in the colloidal state, while anionic chloro- or cyano-gold complexes should be absorbed quite well. Urinary gold may account for 50% of the intake. Gold is used in the treatment of arthritis in various chemical forms, all of which have toxic side effects.zo' Group IIA: Be, Mg, Ca, Sr, Ba, Ra.-Magnesium and calcium are both important and essential dietary constituents, while the other four elements are much rarer and the evidence for their essentiality is minimal. Snyder has plotted the intake of both magnesium and calcium as a function of age, and shown that there is little variation over the age range between 5 and 70 years. The best value for the daily intake of beryllium is an upper limit.40 Despite analytical problems, the urinary outputs of all the alkaline earth metals are reasonably well established, except for beryllium where recent upper limits are much lower than the provisional figure suggested by Snyder.3 The absorption of beryllium is believed to be poor; otherwise the percentage absorbed decreases steadily down the group, e.g., Mg 38-55%: 189,202 Ca 16%: Sr 12%: Ba 5%: Ra 12y7130

D. S. Miller, Proc. Nutr. Soc., 1979, 38, 197. G. G. Graham and A. Cordano, in ref. 1, Vol. 1, p. 363. ' 9 9 M. J. Stiff, Water Res., 1971, 5, 585. T. Sollmann, 'A Manual of Pharmacology', W. B. Saunders, Philadelphia. 1957. 201 C. J. Polson and R. N. Tattersall, 'Clinical Toxicology', Pitman, London. 1969. 19'

198

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Environmental Chemistrv

3.5%. However these percentages have large standard deviations. Roth and Wernerzo2used 28Mg to study magnesium absorption in man and concluded that the absorption curve has a linear and saturable component. Radiotracer studies of human absorption of the alkaline earths have been summed up by Newton et dZo The 3 relatively poor absorption of these divalent metals compared to the alkali metals implies that they form stable complexes with dietary components, for example phytic acid, or perhaps with undigested polymeric material. Calcium has been particularly well studied and two findings are worth mention. One is the steady increase in urinary excretion with age,3 which can give rise to serious losses of calcium from bone.204 The other is the improved absorption of calcium in the presence of Vitamin D. Other dietary components also affect calcium absorption, but none in so marked a manner.2 Absorption of calcium declines in men over seventy years Magnesium deficiency has been found in volunteers after many days ingesting a diet containing 12 mg Mg day-’, which is far lower than any known natural diet.206 Calcium deficiency is known to cause rickets in children and bone-wastage in the aged. Most diets contain far more than the recommended minimum of 220 mg Ca da~-’.~O’Low values of as little as 35 mg Ca day-’ reported for some German diets3’ are probably in error and need confirmation. No toxic limits for calcium or magnesium have been reported. Intestinal absorption adapts rapidly to dietary concentrations ranging from 300 to 2000 mg C a day-1.208Strontium is not toxic if plenty of calcium is available. Barium, in soluble form such as BaCO,, gives rise to toxic symptoms at doses of 200 mg Ba day-’, and may be lethal in acute doses of 560-2800 mg Ba.22*201 Beryllium is probably still more toxic, but no quantitative figures have been traced for man. Humans are said to vary widely in sensitivity of response, but extrapolation from experiments on rats suggests that 700 mg Be might be lethal as a single dose. Group IIB: Zn, Cd, Hg.-These three elements have been intensively studied in recent years, zinc because of its essentiality, and the other metals because local pollution of river basins has resulted in human mortality. The concentration of zinc in normal diets ranges from 4-25 mg Zn day-’, and the lower limit may be close to causing deficiency symptoms. Zinc deficiency certainly occurs in a few individuals living in the Middle East, whose diet consists largely of unleavened bread and This may well be due to poor absorption of the element, as according to intakes appear to be above normal.’ Absorption of zinc is 30-50% Snyder,3 but excretion in the urine is only 4% of intake, so biliary excretion is probably important. Absorption is depressed by phytates, high calcium or high phosphate diets, and is improved by casein extract or liver hydrolysate.* The P. Roth and E. Werner, I n f . J . Appl. Radiat,Isot., 1979, 30, 523. D. Newton, J. Rundo, and G.E. Harrison, Health Phys., 1977,33,45. 2n4 S. H. Cohn, 1. Zanzi. A. Vaswani, S. Wallach, J. Aloia, and K. J. Ellis, Calc$ Tissue Res., 1976, 21, Suppl., 375. 2n5 J. C. Gallagher. B. L. Riggs, J. Eisrnan, A. Hamstra, S. B. Arnaud, and H. F. De Luca, J . Clin. Invest., 1979, 64, 729. M. E. Shils, Am. J. Clin.Nutr., 1964, 15, 133. 207 H. H. Mitchell, ‘Comparative Nutrition of Man and Domestic Animals’, Academic Press, London, 1962, Vol. 1, p. 262, 208 P. Ireland and J. Fordtran, J . Clin. Invest., 1973, 52,2672.

*02

203

The Elemental Content of Human Diets and Excreta

85

pancreas secretes a peptide that acts as a ligand for zinc(I1) cations in the Urinary zinc increases during starvation and after administration of tetracycline drugs.21o Dietary supplements of at least 40 mg Zn day-’ have caused dramatic effects on zinc-deficient dwarves from the Middle East.12 Toxic effects have been found in a subject ingesting 1.4 g Zn’1,211and the acute lethal dose lies between 1.2 and 13 g Zn as zinc sulphate.22*20’ Cadmium may turn out to be an essential element.212Analytical precision is There is some controversy over the amounts in normal diets, as recent measurements have a median of about 0.04 mg Cd day-’,3s,40,43,56,57,59-63, 134* 13’ while earlier value^'^^^^^^^*^^ came nearer to the value of 0.15 mg Cd day-’ proposed by Snyder,3 perhaps from inaccurate analyses. The former value gives a Zn/Cd ratio in the diet much nearer to the ratio in igneous rocks16 than does the latter. Recent values for urinary cadmium are much lower than the 0.1 rng Cd day-’ given by Snyder,3 and suggest that the percentage urinary excretion for cadmium is close to that of zinc. Radiotracer experiments have given useful information on the retention of Io9Cdby volunteer^.^'^ Methyl cadmium derivatives have been reported in the environment but not ~haracterized.~’~ More or less definite symptoms of toxicity have been reported for humans ingesting 3-330 mg Cd11.20’The acute lethal dose is 1.5-9 g Cd”, which is about the same as for zinc,216though lower figures have beer! suggested.22 Mercury is a rare but variable dietary component. It is not easily determined in foods and is readily lost by volatilization. Normal rates of ingestion are probably around 10 pg Hg day-’, but fish-eaters may take in much more, and mercury inhalation is an occupational hazard of some trades and professions, such as dentistry.217Approximately 40% of dietary mercury is excreted in the urine. Rahola et al. have studied long-term excretion of ’03Hg ingested by volunteers.218It is now realized that substantial, and variable, amounts of mercury in the diet are present as methyl mercury derivatives, which are absorbed and metabolized independently and differently from inorganic Absorption of mercury(I1) is 5-1596 220 and is depressed by some natural dietary items as well as by doses of EDTA.2 On the other hand absorption of methyl mercurials is 90-100%.220

W. Evans, C. I. Grace, and H. J. Votava, Am. J . Physiol., 1975, 228, 501. H. Spencer, D. Osis, L. Kramer, and C. Norris, in ref. 1, Vol. 1, p. 345. 211 J. V. Murphy, J. A m . Med.Assoc., 1970, 212, 21 19. 212 K . Schwarz and R. E. Spallholz, in ‘Cadmium 77’, Metal Bulletin, Ltd, London, 1978. *13 P. E. Paulev, P. Solgaard, and J. C. Tjell, Clin. Chem., 1978, 24, 1797. 214 T. Rahola, R. K. Aaran, and J. K. Miettinen, in ‘The Assessment of Radioactive Organs and Body Burdens’, IAEA, Vienna, 1972, p. 553. 215 C. L. Huey, F. E. Brinckmann, W. P. Iverson, and S. 0. Grim, in ‘Heavy Metals in the Environment’, Toronto, 1975, Abstr. C-214. * I 6 C.E.C. (Commission of European Communities), ‘Criteria (Dose/Effect Relationships) for Cadmium’, Pergamon, London, 1978. 2 * 7 L. J. Goldwater and W. Stopford, in ‘The Chemical Environment’, ed. J. M. A. Lenihan and W. W. Fletcher, Blackie, Glasgow, 1977, p. 38. 218 T. Rahola, R. K . Aaran, and J. K. Miettinen, in ‘Proc. Int. Radiat. Protect. Assoc., 2nd Eur. Congr. Radiat. Protect.’, ed. E. Bujdoso, Akad. Kiado, Budapest, 1973, p. 213. 219 J. K. Miettinen, in ‘Ecological Toxicology Research’, ed. A. D. McIntyre and C. F. Mills, Plenum Press, New York, 1 9 7 5 , ~215. . 220 J. J. Vostal and T. W. Clarkson,J. Occup. Med., 1973, 15,649. 209 G. 210

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Mercury is one of the more toxic elements, but its toxicity depends markedly on its chemical form. Thus mercury(0) is scarcely toxic by mouth, and one individual is reported as surviving after taking 9.5 kg2O1The acute lethal dose of mercury(1) is 1.3 g Hg201As little as 28 mg Hg" day-' in the diet can cause toxic symptoms,220 and an acute dose of 130-750 mg Hg" can be fata1.22+201 Methyl mercury derivatives are still more toxic, and cause detectable effects at intake rates of 0.3 mg Hg day-'.220 Acceptable daily intakes of total mercury are 0.06-0.1 mg Hg day-' and assume a high methyl mercury content.22' Group IIIA: B, Al, Sc, Y, Lanthanides, and Actinides.-None of these elements is known to be essential and they have not been studied in detail. They seem to fall into three classes with regard to their metabolism: ( a ) anions, e.g., borate, which is well absorbed and moderately toxic; (b) cations, e.g., M3+ or M4+ are poorly absorbed and scarcely toxic; (c) complex cations, e.g., UOz+ ( + N p O t + and PuOt+), which are moderately to poorly absorbed and highly toxic. Boron enters the diet largely as borates (or derivatives) from plant material, as it is essential to plants.16 Borates are well absorbed and about 75% of the ingested dose is excreted in the urine. Ingestion of an acute dose of 2.6 to 3.5 g B as boric acid has caused death;201normal amounts in the diet are much lower. The amount of aluminium in a given diet depends on such factors as the amount of soil adhering to the food, whether aluminium cooking vessels are used, and the .~ are also analytical problems, notably the amount of baking powder p r e ~ e n t There failure to dissolve particles containing aluminium after dry ashing, and susceptibility to contamination by dust. Tanner and Friedman found 65% of dietary aluminium came from cereal^.^ Absorption is poor, though it is affected by the amount of fluoride in the diet,2 and excretion is at least 99% faecal. The toxicity of aluminium metal is low.l9 However, aluminium(III) sulphate, added to drinking water to clarify it, has proved highly toxic to patients undergoing dialysis treatment in West Scotland.2' A few figures are available for the amounts of Ce, La, Sc, Sm, and Y in diets and urine. These are provisional, but serve to show that intake is less than 1 mg day-' for all these elements, and that urinary excretion is probably < 1 % of intake (except for samarium, for which the urinary analyses should be repeated). None of these elements are particularly toxic. Thorium(1v) follows the same pattern with extremely low concentrations in urine.'72 The dietary concentration of uranium is of the order of 1.5 pg U day-' but can be much higher in uranium-rich regions in R ~ s s i a .The ~ urinary excretion rate is variable, but is reported as only 0.05-1% of intake in enriched areas,' and as 0.1-0.5 p g U day-' elsewhere. The percentage absorption of uranium is 0.55%.222An acute dose of 36 mg U t V is lethal to rats,223which suggests that the corresponding dose for humans would be about 8 g. Uranium has a unique chemistry among the actinides because of the stability of the uranyl cation and its J. G. Saha and K. S. McKinlay, in 'Analytical Aspects of Mercury and other Heavy Metals in the Environment', ed. R. W. Frei and 0. Hutzinger, Gordon and Breach, New York. 1975, p. 1. 222 J. B. Hursh, W. P. Neuman, T. Toribara, H. Wilson, and C. Waterhouse, Health Phvs., 1969. 17, 619. 223 W. S. Spector, 'Handbook of Toxicology'? W. B. Saunders. Philadelphia, 1956. 22i

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complexes. Other actinides are of interest to health physicists studying the ingestion of radioactivity, but are present in very low concentrations and are poorly absorbed. Radioactive measurements are available for plutonium 189,224 and thorium. log Group IIIB: Ga, In, TI.-Very little information is published on these three rare metals. A single report gives a value for urinary excretion of gallium as 42 ,ug G a d a ~ - ' . ' ~When ~ gallium(u1) citrate was intravenously injected, 4-43% was excreted in the urine within one day.225No references to indium have been traced, but thallium has been studied because of its involvement in poisoning. Normal ingestion is perhaps 1.5 pg T1 d a ~ - ' ,while ~ urinary excretion ranges from 0.2-0.8 pg day-l.lg8 One might expect TI' to be much better absorbed than Ga"' or In"'. Certainly, thallium is about a hundred times more toxic to rats than the other two 226 The acute lethal dose for humans is between 0.6 and 1.2 g T1'.Iy-22* 201 Group IVA: Ti, Zr, Hf.-These three metals are much commoner in rocks, soils, and dusts than in foods, so there are contamination problems in analysing diets and excreta. For titanium, the mean dietary intake of 0.8 mg Ti day-' and urinary output of 0.3 mg day-' are supported by the few measurements made.3.34-40 Corresponding values for zirconium are uncertain, since there is a major disagreement between two sets of worker^.^^*'^^ No values have been traced for hafnium, but one would expect the Zr/Hf ratio in diets to be about 35, as it is in the geosphere.16 The absorption of these elements is probably low, though the value for titanium in urine is surprisingly high, and they are scarcely toxic by oral ingestion. Group IVB: Si, Ge, Sn, Pb.-Silicon and tin are both probably essential, while lead has been extensively studied because of its toxicity. There do not appear to be any reliable determinations of silicon in diets or f a e ~ e sbut , ~ an estimate of 1.2 g Si day-' seems reasonable for intake.40 For germanium, the measured values of 1.5 mg Ge day-' (ref. 3) and 0.4 mg Ge day-' (ref. 40) in diets are not wildly dissimilar but need confirmation, as the Si/Ge ratio in rocks is about lo5.The amount of tin in the diet is affected by the proportion of canned food ingested, as quite large amounts of tin are dissolved by some canned products.'29Recent analyses suggest that the daily intake may be nearer 1 mg Sn day-' than the 4 mg day-' proposed by Snyder,3 which exceeds the dietary requirernent.'O Dietary lead is about 0.3 mg Pb day-', and analytical precision is fairly The percentage absorption of silicon and germanium is uncertain, as are the chemical forms found in foods. Urinary excretion is about 10 mg Si day-', but the The value of 1.4 mg Ge day--' seems far too high and needs c~nfirmation.~ absorption of tin is about 2%, while studies with *I2Pb have indicated that absorption of lead is 1.3 to 16%.2277228 Some 10-40% of urinary lead (labelled with z03Pb)is in a form that will not co-precipitate with calcium phosphate.229The P. J. Magno, P. E. Kauffmann, and B. Shleien. Healfh Phw., 1967, 13, 1325. J. 1. Munn, N. H. Walters, and H. C. Dudley, J . Lab. Clin. Med., 195 1, 37, 676. 226 V. Zitko, Sci. Total Enuiron., 1975, 4, 185. "'J. B. Hursh and J . Suomela. US Atomic Energy Commission Rep. U C R L - 18 140, 1968. p. 2 17. 22a M. R. Moore. Pmc. Nufr. SOC.. 1979. 38, 243. 229 M. J. Heard and P. Little. UK Atomic Energy Authority Rep. AERE-PR E M S 6, 1979. p. 5 1. 224

225

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absorption of lead is depressed by high levels of calcium, phosphates, or sulphates in the diet,2 and excretion is greatly increased by dosing with chelating agents such ~'~ as EDTA.I9 High concentrations of tin in urine are associated with ~ r a e m i a .Oral silicates, germanates, and both tin(") and tin(Iv) inorganic species appear to be of low toxicity; 500 mg Sn day-' has been tolerated.200Toxic effects of lead have been claimed when the diet contains 1 mg Pb" day-1.20' Acute toxicity arises from ingesting 350 mg Pb" 201 and the lethal dose is between 5.5 and 1 1 g Pb11.200 Dimethyl- and trimethyl-tin compounds occur naturally in human urine,26 and tetramethyl-lead has been found to be produced by bacteria.230Many organo-tin compounds are used in food processing and packaging, while tetra-alkyl-leads escape into the environment when they are used as additives in petrol. In view of the very high toxicity of trimethyl- and triethyl-tin more studies on their concentration in diets are needed. The absorption and highly toxic action of tetra-alkyl-leads have been well d o c ~ m e n t e d . ' ~After . ~ ~ ~ inhalation of the tetra-alkyl-, dialkyl-, and perhaps trialkyl-leads have been found in the urine.229

Group VB: P, As, Sb, Bi.-The total phosphorus in the diet is about 1.4 g P day-' and about 64% of this is excreted in the urine.3 All dietary phosphorus is believed to be Pv in the form of esters of phosphoric acid or its polymers, as natural compounds containing carbon-phosphorus bonds are rare.I6 Neither phosphorus deficiency nor toxicity has been reported for man, though rickets probably involves deficiencies of both phosphorus and calcium. The estimated daily requirement is 0.5-1 gP Elemental white phosphorus (P4) is not a natural component of food, but is toxic in acute doses of only I5 mg, while 50-500 mg is lethal.201 Arsenic is now believed to be an essential trace element, and the wide range of concentrations reported for human diets mostly lie between 0.05 and 1 mg As day-', with a few lower values from germ an^^'.^^ and the USA.s0Nielsen et al.232 found that rats showed deficiency symptoms on a dietary intake of 0.45 pg As day-', suggesting that the human requirement may be of the order of 0.1 mg As day-'. Sea foods are rich in arsenic,44 and contain organo-arsenicals such as a r ~ e n o b e t a i n e 234 . ~ ~Widely ~. scattered localities in the world have high arsenic ~ New Zealand,236and concentrations in drinking water, e.g., in A l a ~ k a ,Chile,235 In Alaska, individuals may ingest up to 0.32 mg As day-' and excrete 0.18 mg day-' in the urine without any toxic ~yrnptoms.~ The percentage absorption is uncertain, but is probably high for both Asi1' and AsV. Urinary excretion of arsenic is extremely variable and depends on recent dietary intake. Methyl arsonic acid, dimethyl arsinic acid, and trimethylarsine oxide have been found in human urine and are probably normal metabolic waste p r o d ~ c t s . ~ ~ ~ ~ ~ U. Schmidt and F. Huber, Nature (London), 1976,259, 157. P. 3. Smith, 'Toxicological Data on Organotin Compounds', Int. Tin. Res. Inst., Greenford, Middx., 1978. 232 F. H. Nielsen, S. H. Givand, and D. R. Myron, Fed. Proc., 1975,34,923. 233 J. S. Edmonds, K. A. Francesconi, J. R. Cannon, C. L. Raston, B. W. Skelton, and A. H. White, Tetrahedron Lett., 1977, 18, 1543. 234 J. R. Cannon, J. S. Edmonds, K. A. Francesconi, and J. B. Langsford, lnt. Conf. Manage. Control Heavy Metals Environ., C E P Consultants, Edinburgh, 1979. p. 283. 235 R. Zaldivar and A. Guillier, Z . Bakt, Parasitenk, Jnfekt. Hyg. B , 1977, 165.226. 2 3 b P. F. Reay, J. Appl. Ecol., 1972, 9, 557. 237 W. P. Tseng, Environ. Health Perspect., 1977, 19, 109.

230

231

The Elemental Content of Human Diets and Excreta

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In mammals, arsenic(v) is probably the main chemical form in the diet: it is rapidly excreted in the urine and has not been shown to be reduced to As"'. Arsenic(ir1) compounds are more strongly retained from the diet, and are slowly oxidized to arsenic(v) in the body or excreted in bile.238Arsenobetaine in the diet is rapidly excreted in Arsenic(iii) gives rise to toxic symptoms at 5-50 mg As day-' and the acute lethal dose to man is 90-2100 mg As.~',~O'Arsenic(v) is much less toxic and experimental doses of at least 18 mg As day-' have been tolerated.200 The estimate of 50 pg Sb day-' in diets by Snyder is rather higher than values ' ~ ~ ~ , median ~ ~ ~ ~ ~ is nearer 15 pg Sb day-'. published ~ u b s e q u e n t l y , ~ ~ - ~ whose , ~ ~ may Hospital diets have been reported to contain 400-900 pg Sb d a ~ - ' which be caused by use of enamel food vessels, or reflect inaccurate analyses. Urinary excretion ranges from
90

En u ironmen f aI Chemistry

(0.006 mg Se day-' may well be deficient for humans, but lower intakes have been reported from Italy 3 9 , 4 2 and New Zealand.'02 Endemic cardiomyopathy among the population of Keshan, China, where selenium is deficient, has been cured by supplementing the diet with 0.065-0.13 mg Se" day-'.'O' In other locations, grazing cows and horses have been poisoned by ingesting too much selenium, but such toxic effects are very rare for humans.6*'5A reasonable estimate for the acute oral toxicity to man might be 250-500 mg Se"; 72 mg Se" has proved fatal to a child.201 The amount of tellurium in the diet is uncertain. The only measured values ~ need confirmation. The appear in a correction to a paper by Schroeder et ~ 2 1 . ' ~and urinary excretion figures from the same workers also seem high. Tellurium is probably well absorbed as Te". Doses of 1-10 pg Te" cause exhalation of dimethyl telluride, which smells of garlic.2002 g tellurium(1v) accidentally given by catheter have proved Tellurium(v1) is less toxic, and an individual is known to have eaten 140 mg TeV1over a period without lasting effects.200 Polonium is a very rare element whose great toxicity is due to its alpharadioactivity. Concentrations of about 0.15 Bq 210Poday-' occur in the diet,246and 90% of this is excreted in the faeces.247 Group VIIB: F, CI, Br, 1.-With the probable exception of bromine, all the halogens are essential to mammals. Chlorine is a major dietary constituent, in variable amounts depending on salt addiction. Fluorine, bromine, and iodine are minor components whose dietary intakes per day are thought to be about 2 mg F, 4 mg Br, and 0.2 mg I. All are believed to be ingested mainly as halide anions, which are well absorbed,I8 75-95% of the intake appearing in the urine. Many organic chlorides, bromides, and iodides, and a few fluorides, occur naturally, and could be ingested in sea foods, especially those made from red algae.I6 Some iodine may occur as iodate(IV)in foods or iodized salt. The absorption of fluoride is said to be depressed by high aluminium in the diet,2 and is reduced from 100% to 60% by intake of milk Diets containing 70 mg CI day-' are said to be deficient, but are not found naturally. The optimum amount of fluoride in the diet has given rise to much c o n t r ~ v e r s y In . ~ Britain and North America, food alone provides 0.2-0.5 mg F day-', with as much again or more in drinking water. When fluoridated water is drunk, the intake may rise to 5 mg F d a ~ - ' .Both ~ sea foods and infusions of tea are rich in fluorine, so it is not surprising that Japanese diets contain 4.5 mg F d a ~ - ' . ~ ~ Rats show fluorine deficiency symptoms when fed less than 5 pg F day-1,24ywhich suggests but does not prove that humans require at least 1 mg F day-'. Fluorine deficiency in children is associated with increased tooth decay. l 4 Dietary needs of iodine are said to be 70-100 pg I day--'.20p207 Diets containing 15 pg I day-' are deficient and are one cause of goitre.14 It has been suggested that urinary excretion of less than 40 pg I day-' indicates iodine deficiency.25o E. Cerwenka and W . C. Cooper, Arch. Environ. Health, 196 1 , 3, 189. Y. D. Parfenov. Atom. Energy Rev., 1974, 12, 75. 247 S . Jackson and G. W. Dolphin, Health Phvs., 1966, 12.48 1 . 24a J. Ekstrand and M. Ehrnebo, Eur. J. Clin. Pharmacol., 1979, 16. 2 11. 249 K. Schwarz and D. B. Milne, Bioinorg. Chem., 1972, I . 33 1. 2 5 0 R. H. Follis, Am. J. Clin. Nutr., 1964, 14. 253. 245

246

The Elemental Content of Human Diets and Excreta

91

It is difficult to eat too much chloride and the anion is practically non-toxic. Higher valency states such as chlorates (Cl') are more toxic and an acute dose of 2.9 g Clv has proved fatal.22Bromides are soporifics and an acute dose of 2-3 g Br is toxic, while 20-80 g Br is lethal.201Bromates (Br') are rather more toxic,20' and elemental bromide (Br2) is very poisonous. Fluoride toxicity is known from parts of India where the drinking water is rich in the element.251More than 20 mg F day-' in the diet leads first to mottling of the teeth and then to crippling bone diseases.14 An acute dose of 170 mg F ingested accidentally was toxic, and the acute lethal dose is 1.1-4.5 g F.201No toxic effects of iodides were found in subjects taking 4.6 g I day-1.200The lethal dose is probably of the same order as that for bromides, about 30 g I; 48 g I given intravenously has proved Transition Metals of Groups V-VII: V, Nb, Ta; Cr, Mo, W; Mn, Re.-Among these metals, manganese and molybdenum are certainly essential, and occur in specific proteins, chromium and vanadium are probably essential, and the rest are uncertain. All of them show a wide range of valency states, and all except manganese occur in the environment as anions in their highest valency state. CrIII, Mn", and perhaps V" probably occur as cations in foods. Recent analyses 43.96*107, 191 suggest that the vanadium content of diets and urine is two orders of magnitude lower than the figures given by Snyder.3Absorption of vanadium is poor, probably less than 2%, but urinary concentrations are too low to determine by any known method. These studies raise the question as to whether vanadium is truly essential, and render earlier observations on its adequacy in the diet obsolete. Toxic to lethal effects have been reported from an intravenous dose of 18 mg Vv.I9 Analysis of a diet by Hamilton and Minski40 gave one thirtieth of the intake of 0.62 mg Nb day-' found earlier,95so the urinary excretion figures given in the latter paper need confirmation. Tracer studies with 95Nbshow that about 1% of Nb" is absorbed.252Information about the chemically similar element tantalum is restricted to a single report of less than 1 ,ug Ta day-' in the diet.40 There has been controversy about the reliability of chromium analyses, and recent work suggests that the intake may be closer to 0.05 mg Cr day-' rather than the 0.15 mg day-' favoured by Snyder.3 Urinary excretion is probably about 0.00 1 mg Cr d a ~ - ' , ~but ' analyses are subject to contamination, i n t e r f e r e n ~ e , ' ~ and ',~~~ loss problems so that many reported values are higher. The dietary need for chromium is said to be 0.01-0.03 mg Cr day-1,254but lower intakes have been found in Italy and USA.39*42-255 Absorption is about 0.5% for Cr"' and
252

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German diets.37 U p to 15 mg Mo day-' may be ingested in molybdenum-rich regions, and this increases the urinary excretion of copper.2 Absorption of Movl is good, with about 75% of the ingested molybdenum appearing in the urine, but is depressed when the diet contains large amounts of sulphates.' Neither molybdenum deficiency nor toxicity have been reported from human populations, and animal experiments indicate that Mo'' is about as toxic as CU".~' The dietary intake of tungsten is probably about 0.01 mg W day-', and a reasonable median for urinary excretion is 0.007 mg W day-'. Absorption of Wvl is probably about the same as that of Mo", and the toxicity to animals is also similar.,' Manganese in diets averages about 4 mg Mn day-', which is not much greater than the estimated requirement of 2.5 mg Mn day-'.*O Somewhat lower values have been reported.', 1 3 , 3 5 Most dietary manganese comes from plant foods, notably from tea,' and it appears that Asian diets are rich in the element.'3p45,49It is poorly absorbed, but strongly retained, by the body. Urinary concentrations are now thought to be extremely 10w,31*169 although analysts continue to report values one or two orders of magnitude greater. Manganese toxicity has been seen in abnormally exposed populations such as miners. Mn" is not very toxic, but permanganates are more poisonous and an acute dose of 3.5-7 g MnVl1is lethal.'"' Hamilton and Minski4' found <1 pg Re day-' in a UK diet, but nothing more is known about the absorption and excretion of this rare metal by man. has Transition Metals of Group VIII: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt.-Iron been thoroughly investigated because of its metabolic importance. Cobalt and nickel, which are also essential, have received less attention, and the platinum metals have been almost totally neglected. The dietary intake of iron is about 16 mg Fe day-', and its variation with age has been p10tted.~Dietary requirements are said to be 5-9 mg Fe 6-100 mg Fe d a ~ - ' , 'or~ ~10-18 mg Fe day-',,O and intakes at the lower end of this range are not uncommon, when they may lead to iron defi~iency.'~ About half the dietary iron occurs in cereals,' and much of it is in the form of haems, especially in meats and legumes. Absorption is poor, and urinary excretion is about 1% of intake. Factors affecting iron absorption have been reviewed,'g3 and it emerges that iron(I1) is better absorbed than is iron(III), and that women absorb iron better than men do. Some African diets, especially those containing the cereal teff, contain as much as 390 mg Fe day-' which can cause chronic iron i n t o ~ i c a t i o n . The ' ~ ~ ~acute ~ lethal dose of iron(I1) is about 2.3 g Fe.22 Concentrations of dietary cobalt are a matter of controversy, as recent work 9 . 3 7 - 3 9 , 4 2 , 4 3 supports a daily intake of about 20 pg Co, which is an order of magnitude less than that given in Snyders reviewq3The mean intake of Vitamin B,, in Britain is 6.6 pug day-','' corresponding to 0.28 pg C o day-'; hence deficient diets should contain less than 0.2 pg Co day-'. Although cobalt deficiency has been found in grazing animals' it has never been noted in human pop~1ations.l~ Absorption is uncertain, since there is no agreement about the amounts in urine. Careful work by Cornelis el al. indicates that urinary excretion is of the order of 1 pg C o day-' rather than the 200 pg Co day-' given by Snyder.3 Natural cobalt toxicity is unknown, but an acute dose of 230 mg Co" is toxic.*'

The Elemental Content of Human Diets and Excreta

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Dietary nickel is probably about 0.4 mg Ni day-', and occurs mainly in plant foods.2 The normal intake is more than the suggested dietary need of 0.035-0.06 mg Ni d a ~ - - ' . Absorption ~~' is poor, and urinary excretion is about 2.5% of intake. Nickel(i1) is moderately toxic to rats.29The precision of urinary analysis is poor.258 Workers in industry can excrete up to 3 mg Ni day-' in urine but this is exceptional. 260 Our only information on the platinum metals in the diet comes from the work of Hamilton and M i n ~ k i , ~who ' give upper limits of 1 pg day-' for the intake of osmium, iridium, and platinum. The actual values are probably one to three orders of magnitude less than this and offer a challenge to current analytical methods. Some forms of the platinum metals can be rather toxic, notably RuVII1and 0sV1I1, but also compounds of Pd" and Pt". 2599

2599261

5 Summary

Knowledge of the current daily intakes of most elements is fairly good, but analytical problems beset the determination of the rarer elements and are particularly troublesome for urine samples. With regard to deficiencies we know much more about the dietary needs of the laboratory rat than those of human beings, but some natural diets may possibly be deficient in As, Cr, Cu, F, Fe, I, Se, and Zn. Information on the acute oral toxicity of elements to man has been gleaned from very few cases of accidental poisoning. It seems clear that chronic toxic limits are rarely exceeded in natural diets with the possible exception of As, F, Fe, and Se. We are notably ignorant of the predominant chemical forms of most elements in both diet and urine, and until these are better known we cannot hope to understand the more complex problems of intestinal absorption and excretion.

F. H. Nielsen, in ref. 1, Vol. 2, p. 379. D. B. Adams, S. S. Brown, F. W. Sunderman, and H. Zachariasen, Clin. Chern., 1978, 24,862. 259 I. C. Smith and B. L. Carson, 'Trace Metals in the Environment', J. Wiley, New York, Vol. 4. 260 H. Hagedorn-Gotz, G. Kiippers, and M. Stoeppler, Arch. Toxicol., 1977, 38, 275. 261 R. D. Gillard, in 'New Trends in Bio-inorganic Chemistry', ed. R. J . P. Williams and J. R. R. F. D a Silva, Academic Press, London, p. 85. 262 R. L. Koretz and J . H. Meyer, Gasfroenterology, 1980, 78, 393.

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3 The Elemental Constituents of Soils BY A. M. URE AND M. L. BERROW

1 Introduction

The general principles that determine the levels of occurrence of trace elements in soils have been reviewed by Mitchell.’**The total contents of relatively young soils in cool temperate regions, such as those in Scotland, are related primarily to the geological nature of the rocks from which their parent materials are derived. In such soils, the normal pedological processes have brought about little or no depth differentiation in the total contents of trace elements within the p r ~ f i l e Numerous .~ other workers in many different countries have confirmed that the total trace element content of a soil is basically determined by the content of the parent material when it has been only slightly This relationship holds for metallic trace elements as well as for those such as B ” and SeI8 which exist in rocks and soils largely in anionic form. For some trace elements the total content may vary by a hundred or even a thousandfold from soil to soil depending upon its origin. The total contents of the major constituents (0, Si, Al, Fe, Ca,. Na, K, Mg, Ti, and P), however, which constitute over 99% of the total element content of the earth’s crust, seldom vary from soil to soil by more than five fold.’ Differences in total contents of the major elements in soils are not therefore so indicative of their geological origin.

’ R. L. Mitchell. in ‘Chemistry of the Soil’, 2nd Edn., ed. F. E. Bear, Reinhold, New York, 1964, p. 320. ’ D. J. Swaine and R. L. Mitchell, J . Soil Sci., 1960. 11, 347. N. Wells, J . Soil Sci., 1960, 11, 409. ’ F. C. Archer,J. Sail Sci., 1963, 14, 144. J. C. Burridge and P. M. Ahn, J . Soil Sci., 1965, 16, 296. ’G. R. Webber and J. U. Jellema, Can. J . Earth Sci.. 1965, 2, 44.

’ R. L. Mitchell, Geol. SOC.Am. Bull., 1972. 83, 1069.

I”

S. Lentschig and H. J. Fiedler, Abh. Sraatl. Mus. Mineral. Geol. Dresden, 1966, 1 I,28 I . J. Laruelle and G . Stoops, Pedologie Cand., 1967, 17, 232. G. A. Fleming, T. Walsh, and P. Ryan, Trans. 9th Int. Congr. Soil Sci.. 1968, 2 34 1.

I’

P. V. Klimovich, Geogr. Doslidzh Ukr., 1969, 29: Chem. Abstr., 1971. 75, 79 201. R. H. Follett and W. L. Lindsay, Colorado State University Exper. Sta. Technical Bulletin, 1970, 110.

K . P. P. Nair and A. Cottenie, Geoderma., 1971, 5 , 81. l 4 G. Stoilov and I . Atanasov, Izv. Timiryazevsk. S’kh. Akad., 1971, No. 3, 141. l 5 E. Barragan Landa and J . Iiiiguez Herrero, A n . Edafol. Agrobiol., 1973. 32, 89. I 6 T. Higashi, Bull. Fac. AKric. Yamaguti Unit)., 1973, No. 24, 673. ” J. Maurice, Ann. Agron., 1973, 24, 465. M . Levesque, Can. J . Soil Sci., 1974, 54, 63. I3

94

The Elemental Constituents of Soils

95

In soils in which considerable weathering of the primary rock-forming minerals has taken place the behaviour of the trace elements is controlled by other factors including the nature of the accessory primary minerals, the nature of the secondary minerals being formed, the extent of leaching and the degree of organic matter accumulation. The relationship between parent material and soil trace element content can be expected to be maintained, even in strongly weathered soils, for those trace elements that occur in very stable minerals or are strongly bound to the secondary weathering products and are thus not subject to leaching. The situation is different, however, for readily mobilized constituents in such soils. From a study of Queensland soils, no simple relationship between the trace element content of the surface soils and of the parent material was f ~ u n d . This ' ~ is presumably because these Australian soils have undergone intense weathering over long periods. On the basis of a study of 54 soils profiles from Queensland, Central Australia, and Tasmania, however, a significant correlation between the trace element content of the parent materials as represented by the C horizons and the weighted means of the A and B horizons (the solum) has been demonstrated.20 Under tropical conditions, where weathering is more intense than in temperate climates, the trace element content of a soil is very dependant upon pedogenetic factors, as has been found in Burma,21 in Madagascar,** and in C a m e r o ~ n The .~~ geochemical principles controlling the distribution of trace elements in soils have been discussed by Pedro and D e l m a ~ These . ~ ~ authors have concluded that their contents depend ( a ) on the nature of the parent material, particularly on the forms in which the trace elements occur, and ( b ) on the extent of modification it has undergone during soil development, i.e., on the age of the soil and the prevailing pedologic a1 we athering. Other sources of trace elements which can affect levels in soils are beneficial agricultural additives, including lime, fertilizers, manure, herbicides, fungicides, and irrigation waters, as well as other materials such as sewage sludge, composts, fly ash, mine waste, and atmospheric deposition, the compositions of which are affected by man's industrial activities. The relative importance of these sources have been discussed by Berrow and B ~ r r i d g e . 'Pollution ~ sources of metals in the United States have been discussed by Cannon.2h In the following sections detailed consideration is given to the soil contents of almost all the naturally occurring chemical elements. A few elements, notably the rare gases, rhenium, and tellurium are omitted because of the lack of information. In the tables of soil contents, the values quoted are given in order of date of publication, as it is likely that the more recent values may be more reliable. An indication of the biological importance of the elements is included and a brief " J . B. Giles, C S l R O Div. of Soils, Divisional Report, 1959. No. 1/59. A. C. Oertel. J . Soil Sci., 196 1, 12, 1 19. 'I A. 1. Obukhov, S O P Soil . Sci., 1968. No. 2, 224. ** L. Nalovic and M. Pinta, Geoderma, 1969, 3. 117. 23 L. Nalovic and M. Pinta. Geoderma, 1972, 7, 249. 24 G . Pedro and A.-B. Delmas, Ann. Agron., 1970, 21.483. 2 5 M. L. Berrow and J . C. Burridge, Proc. Int. Con$ Management and Control of Heavy Metals in the Enuironmenr, London.. C E P Consultants Ltd.. Edinburgh. 1979,304. 26 H. L. Cannon, in 'Geochemistry and the Environment'. National Academy of Sciences. Washington DC, 1978. Vol. 111, 17. 2o

En u iron men fa1 Chemistry

96

account of their geochemistry, largely based on Handbook of Geochemistry, Vol. I1 edited by K. H. Wedepohl is also given. 2 The Alkali Metals: Lithium, Sodium, Potassium, Rubidium, and Caesium

Geochemistry.-These reactive elements occur almost entirely bonded to oxygen in silicates or halogen in halides. The bulk of the alkali metals in the earth’s crust is to be found in the alkali feldspars and micas, although Li occurs to a considerable extent in phosphates as well as in silicates. Differences in their properties and the extent to which mutual substitution occurs in minerals are largely a consequence of differences in their atomic and ionic radii. Hence, K - and Na-feldspars, for example, form solid solutions only in minerals formed at high temperatures. Sodium and calcium occur in the solid solution series of plagioclase feldspars, from albite, NaAlSi,O,, to anorthite, CaAI,SiO,, and the phase relations of K, Na, and C a feldspars have been widely discussed (see for example ref. 27). Li and Rb form no specific minerals in which they are principal components. Lithium with its smaller atomic and ionic radii seldom replaces Na in minerals but can replace A13+,Fez+, and particularly Mg2+. Lithium partly replaces Mg in some tourmalines and Mg and A1 in Li-rich micas such as lepidolite and chlorite. The similar radii of K + and Pb2+ account for the traces of PbZ+ found in K-minerals, and the similar crystallochemistry of K and Ba results in the occurrence of Ba as a minor constituent in these minerals. Li, Rb, and Cs are dispersed mainly in the K-minerals where they replace K, but Cs does form the mineral pollucite in pegmatites. Rb and T1 are associated in, for example, muscovite and microcline. The K-feldspars are not formed to any extent in the early stages of magmatic differentation, whereas Na-feldspars are found throughout the differentiation process. Potassium contents and those of Li, Rb, and Cs increase during differentiation but K :Rb and K :Cs ratios decrease as this process relatively enriches the later stages with respect to Rb and Cs. The K :Rb ratio is generally in the range 1 6 L 6 0 0 , averaging about 230.28The geochemistry of the alkali metals is comprehensively reviewed by W e d e p ~ h l . ~ ~ The average K content of igneous rocks (Australia) is quoted as 2.33%30with a crustal average of 1.08%.3’ The principal K-minerals in igneous and metamorphic rocks are the feldspars, micas, leucite, and nepheline. The average Na-content of the earth’s crust is estimated at about 2.37%.31 The average crustal contents are, for Li, 20 mg kg-’;29 for Rb, 100 mg kg-1;32 and for Cs, 3 mg kg-’.29 Highest Cs contents are found in muscovite, beryl, and in the Li-rich micas for which the analytical data has been reviewed.33

*’T. F. W. Barth, ‘Feldspars’, Interscience, Chichester, 1969.

K . S. Heier and J . A. S. Adams, Phys. Chem. Earth., 1964, 5 , 253. K . H. Wedepohl (ed), ‘Handbook of Geochemistry’, 1111/3, 11-1/11, 11-1/19, 11-4/37, 11-4/55, Springer-Verlag,Berlin. 30 G. A. Joplin, Bur. Min.Res. Geol. Geophys. Bull., 1963, No. 65,446 pp. ” S. R. Taylor and A. J. R. White, Bull. Volcanol., 1966, 24, 177. 3 2 P. M. Hurley, Geochim. Cosmochim.Acta, 1968, 32, 273. 3 3 N. D. Foster, US Geol. Suru. Prof. Pap., 1960, No. 354-E, 115. 29

The Elemental Constituents of Soils

97

Weathering and Mobility.-Lithium-containing minerals weather to produce Lit, which can be lost by leaching or adsorbed by clays. Losses in the weathering processes are, however, small (see ref. 48). In general Li is not readily leached from soil, since, although it does not play a role in the readily exchangeable sites in clays, it can substitute in the octahedral layer where it is retained against normal leaching processes. In poorly drained (Scottish) soils, Li is concentrated in clays relative to sands but this is not found in freely drained soils.’ Podzolization can produce losses of Li from topsoils.34 A high correlation between Mg and Li contents is observed in lagunal sediments.35 Lithium has been suggested36 as an indicator of marine deposition in shales. It is not bound by humic materials in soils. Sodium is much less strongly bound on soil exchange surfaces than K since the effective (hydrated) radius of Na+ is greater. Sodium is therefore more easily leached from soils than K and the N a :K ratio decreases during pedogenesis.2s The K content of very young soils derived from granitic parent materials is controlled by the weathering rate of K-feldspars,28 a rate affected by pH, the concentration of A1 and Si in solution, and the rate of formation of hydrated A1 silicates.37*38 Potassium released by weathering is adsorbed by soil colloids and clays but may form K-minerals such as illite. No chelates or insoluble salts of K exist in soils nor is K fixed in organic c ~ m b i n a t i o nLosses . ~ ~ by K by leaching are small except in light or sandy soils where K may be concentrated in the subsoils. The mechanisms of fixation and release of K in clay minerals is discussed by Beckett40 and its soil mineralogy by The concentration of K contributed to soil by rainfall has been calculated (New Zealand) as 3 g m-z year-14* and equated with drainage losses by C ~ o k e . ~ ~ Rubidium is more firmly adsorbed by clays than is K and the K : R b ratio decreases during weathering. Caesium is preferentially adsorbed by most clays.29 The deposition by fall-out from the atmosphere of the radioactive isotope I3’Cs on soils is briefly considered in a later section (Radionuclides). The distribution and loss of K-Rb-Cs from a watershed in Sierra Nevada have been determined in a study of weathering and d e n ~ d a t i o n . ~ ~ Soil Contents.-Lithium. Soil contents given for Li in Table 1 average some 31.4 mg kg-I with a range from 1.5-530 mg kg-I. The distribution in soil profiles shows no pronounced features although the contents of organic soils are low, especially in forest litters where it averages only 1.7 mg kg-1.34The effect of saline 34

N. Wells and J. S. Whitton, N . Z . J . Sci., 1972, 15, 90.

’’ Y. Tardy, G. Krempp, and N. Trauth, Geochim. Cosmochim. Acta, 1972, 36,397.

M. L. Keith and E. T. Degens, in ‘Researches in Geochemistry’, ed. P. H. Abelson, John Wiley, New York, 1959, ‘Geochemical indicators of marine and fresh water sediments’. 37 J. H. Feth, C. E. Robertson, and W. L. Polzer, US Geol. Surv. Wafer-Supply Pap., 1964, No. 1535-1. 38 R. Wollast, Geochim. Cosmochim. Acta, 1967, 31,635. 3 y P. B. Tinker, Chilean Nitrate Agric. Service Information., 1967, No. 97, 12 pp. 40 P. H. T. Beckett, Ministry of Agric., Fish and Food, Tech. Bull., HMSO, London, 197 1, No. 20, p. 183. 4 1 C . I. Rich, Am. SOC.Agron.. Crop Sci. SOC.Am., Soil Sci. SOC.Am., Madison, Wisc., USA, 1968, p. 79. 4 2 R. Miller, N . Z . J . Sci., 196 1, 4, 844. 4 3 G . W. Cooke, Potash Review, No. 7, Rothamsted Experimental Station, Harpenden, 1974, 2 pp. 44 T. Hinkley, Geol. SOC. A m . Bull., 1974, 85, 1333. 36

98

En vironmen ta 1 Chemistry

Table 1 Lithium soil contents (mg Li kg - I ) Soils

Range

1 17 soils; Compilation up to 1965 6-200 4 1 soils, Scotland, 8 profiles 3-530 1 13 soils, Madagascar, 26 profiles 9.6-43 110 soils, Cameroon, 18 profiles 1.5-175 72 topsoils, New Zealand 5-136 9 I2 topsoils, USA 65 soils, India, 9 profiles 29.O-3 6.8 USSR soils 5 1 topsoils, Denmark 7-200 10 topsoils, Scotland 6-40 23 soils, Scotland, 4 profiles Overall Mean 3 1.4 mg Li kg-' 1514 Soils

Mean 26 80 86.4 15

50 24.7 33 65 8.6 54 25

ReL 29 3 22 23 34 a h C

d

H. T. Shacklette, J. G. Boerngen, J. P. Cahill, and R. L. Rahill, US Geol. Surtl. Circ., 1973, No. 673, pp. 8; * U. C. Shukla and K. G . Prasad, Indian J . Agric. Sci., 1973. 43,934; ' B. K . Shakuri, Sot.. Soil Sci., 1976, (8). 498: d J . C. Tjell and M. F. Hovmand, Acra Agric. Scand.. 1978. 28. 81: ' A . M. Ure, J. R. Bacon, M. L. Berrow. and J. J . Watt, Geoderma, 1979, 22, 1:JM. L. Berrow and R. L. Mitchell, Trans. R . Soc. Edinburgh: Earth Sci., 1980, 71, 103

waters in increasing Li contents and on its profile distribution are discussed by Gupta et Lithium is not an essential element, but has important biological and toxicological effects in plants, soils,46and man. Toxic effects in sensitive plants such as citrus have been attributed to Li in irrigation waters4' and abnormally high Li has been found in plants grown in soils illuviated by hydrothermal waters.48 A discussion of Li toxicity in grass seedlings has recently been published.49 In a study of the bioge~chemistry~'of Li, plant uptake was found not to be correlated with total Li content but depended on soil type, salinity, and water-soluble Li contents.

Sodium. Sodium contents of soils are presented in Table 2 and the calculated average of 1207 soils is 1.09% Na with a range of < O.OO5-10%. Sodium is an Table 2 Sodium soil contents (% Na) Soils Range 175 soils: Compilation up to 1966 134 topsoils, S.W. Pacific 863 topsoils. USA <0.005--10 0.5-2.5 23 soils, Scotland, 4 profiles 12 topsoils, S.E. USA 0.007-0.22 1207 Soils Overall Mean 1.09% Na

Mean 0.62 1

.oo

1.2 1.53 0.090

R ef: a 4 b c

d

"'Handbook of Geochemistry'. ed. K. H. Wedepohl. I 1 1 / 1 1. Springer Verlag, Berlin: H. T. Shacklett, J. C. Hamilton. J. G. Boerngen. and J . M. Bowles. U S Geol. Sun>.ProJ Pap., 1971, No. 574D: ' M . L. Berrow and R. L. Mitchell, Trans. R. SOC.Edinburgh: Earih Sci.. 1980. 71. 103: P. J. Lechler. W. R. Roy. and R. K . Leininger. Soil Sci., 1980. 130,238 I. C. Gupta. S. K. Singha, and G. P. Bhargava, 1.Indian Soc. Soil. Sci.. 1974, 22, 88. G. R. Bradford, in 'Diagnostic Criteria for Plants and Soils', ed. H. D. Chapman, University of California. 1966, p. 2 18. 47 G. R. Bradford, Soil Sci., 1963, 76. 77, 48 N. Wells and J. S. Whitton, N.Z. J . Sci., 1966, 9, 982. 49 F. A. Sneva. Plant Soil., 1979, 53, 219. 50 J . Bolton, J . Sci. Food Agric.. 1973, 24, 721. 4s

46

99

The Elemental Constituents of Soils

essential element and additions of sodium chloride to soils can provide increased yields of some plants. Some show no response to added sodium, some respond when K levels are low and others even when K levels are adequate. Some degree of overlap exists in the roles of Na and K in plant nutrition and this aspect is discussed in detail by Tinker.39

Potassium. The overall mean content of 2011 soils is 1.83% K, Table 3, with a The fact that the bulk of K in most soils is in the silt and range of 0.005-7.9%. clay fraction^^^.^^ accounts for the distribution of K in profiles. A correlation coefficient of 0.81 was obtained between the K and clay contents of an extensive range of 204 soils in Finland.52As depth increased from 0-30 to 40-1 10 cm in Armenian brown soils, K decreased from 1.5 to 1.1%.53Potassium is an essential element for plants and animals and its key role in agriculture is reflected in a vast literature on available, extractable, and exchangeable K in soils and its uptake by plants, an aspect not wholly pertinent to this work. General treatments of these aspects of K in soils, plants, and agriculture can be found for example in

Table 3 Potassium soil contents (% K) Soils Range 119 soils; compilation up to 1965 0.04-7.9 134 topsoils, S.W. Pacific 139 soils, Quebec, B-horizons 193 topsoils, USSR 0.7-3.8 863 topsoils, USA 0.005-7 USSR Chernozems I .86-2.2 1 15 1 soils, W. Indies 0.07-5.2 22 topsoils, India 0.79-1.36 4 topsoils, Malaya 0.03-1.19 102 surface soils, Finland 102 subsoils, Finland 40 Rice field soils, India 0.20-1.91 10 surface soils, India 0.82-2.4 0.90-1.86 10 subsoil, India Alluvial soils, Colombia/Venezuela 87 soils, Algeria, A horizons 23 soils, Scotland, 4 profiles 0.45-2.7 12 topsoils, S.E. USA 0.058-2.52 201 1 Soils Overall Mean 1.83% K

Mean 1.39 0.68 1.37 2.04 2.3 -

1.14 1.10 0.37 2.20 2.50 1.06 1.46 I .44 0.78 1.03 I .42 0.67

R ef: a 4 7 b 77 63* 59 57 50 52 52 58 C C

61 64 d e

* Not included in Mean ‘Handbook of Geochemistry’, ed. K. H . Wedepohl, 11-2/19; V. F. Brendakov, S. V. lokhelson, and V. N. Churkin, Soc. Soil Sci., 1967, (1). 3 1. ‘J. S. Choudhari and B. L. Pareek, J. Indian SOC.Soil Sci., 1976, 24, 57; M. L. Berrow and R. L. Mitchell, Trans. R . SOC.Edinburgh: Earth Sci.,1980. 71, 103; P. J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci.. 1980, 130, 238 a

’’M. I. Perevalov and N. N. Poddubnyi, Izv. Timiryazevsk. S’kh. Akad., 1974, No. 1, 74. 52

53

A. Kaila, J . Sci. Agric. SOC.,Finland, 1973, 45, 254. L. A. Araratyan, Biol. Z h . Armenia., 1971, 24, 75.

Environmental Chemistry

100

references.39354-56 Recent publications on the K status of agricultural soils include 5 8 Finland,52 West in die^,^^ Ghana,60 Colombia/ studies on soils of India,57* Venezuela,61 Tonga,62 USSR,5’363and Algeria.64 The effect of controlled fire in increasing the topsoil K content has been disc~ssed.~’

Rubidium. The range of Rb contents in Table 4 was 1.5-1800 mg kgg’ and the mean content of Rb calculated for some 972 soils was 120 mg kg-’, in good agreement with the mean of 140 given in an earlier c ~ m p i l a t i o nRubidium .~~ is not an essential element but is taken up by plants. In plants a K :Rb ratio of 1000 has been indicated.66 Caesium. Information on Cs contents of soils is scant although early workers indicated a range of 0.3-25.7 mg kg-’ for soils of France and Italy,67a mean value Table 4 Rubidium soil contents (mg Rb kg-’) Soils Range Compilation up to 1965 1.5- 1800 4 1 soils, Scotland, 8 profiles 30- 1500 139 soils, Quebec, B horizon 113 soils, Madagascar, 26 profiles 10-920 110 soils, Cameroon, 18 profiles 22.6-225 7 soils, Brazil 4-80 40 soils, Bulgaria 63-420 259 topsoils, Wales 29- 160 230 subsoils, Wales 47-170 10 topsoils, Scotland, Different parent mat. 35-190 23 soils, Scotland, 4 profiles 6-150 972 Soils Overall Mean 120 mg Rb kg-’

Mean 140 302 100 212 96.3 30 179 89 99 91 60

Re$ a* 3 7 22 23 6 c

d d e

f

* Not included in Mean ‘Handbook of Geochemistry’, ed. K. H. Wedepohl, 11-4/37: C. C. Dantas and H. Ruf, Radiochim. Aria, 1975, 22, 192; “ M . Naidenov and A. Travesi, Soil Sci., 1977, 124, 152; “ R . I. Bradley, C. C. Rudeforth, and C. Wilkins, J . Soil Sci., 1978, 29, 258; ’ A . M. Ure, J . R. Bacon, M. L. Berrow, and J. J. Watt, Geoderma, 1979, 22, I ; ’M. L. Berrow and R. L. Mitchell, Trans. R . Soc. Edinburgh: Earth Sci., 1980, 71, 103 Ministry of Agric., Fish and Food Tech. Bull., HMSO, London, 1967, No. 14, 195 pp. V . J. Kilmer, S . E. Younts, and N. C. Brady (ed.), ‘Role of Potassium in Agriculture’, Am. SOC. Agron., Crop Sci. SOC.Am., Soil Sci. SOC.Am., Madison, Wisc. USA., 1968, 509 pp. 5‘ Ministry of Agric. Fish and Food., Tech. Bull. ‘Residual Value of Applied Nutrients’, HMSO, London, 1971, No. 20. 5 7 R. K. Bhatnagar, G. P. Nathani, S. S. Chouhan, and S. P. Seth, J . Indian Soc. Soil Sci., 1973, 21, 429. ” S. S. Devi and R. S. Ayer, J . Indian SOC.Soil Sci., 1974, 22, 32. 5 9 N. Ahmad, I. S. Cornforth, and D. Walmsley, Plant Soil, 1973, 39,635. 6o D. K. Acquaye, Proc. 10th Colloq. Internat. Potass. Inst. Abidjan., 1973, 51. T. F. Fuentes and J. J. Gamboa, Turrialba., 1975,25, 371. R. Lee and J. P. Widdowson, Trop. Agric., 1977, 54, 25 1. 6 3 P. G. Aderikhin and A. B. Belyaev, Pochuovedenie., 1973, No. 10.99. “ H. Mutscher, Beitr. Trop. Landwirtsch. Veterinarmed., 1978, No. 1.43. J. R. Boyle, Commun. Soil.Sci. Plant Anal., 1973, 4, 369. “ M. Florkin and H. S. Mason, (ed.), ‘Comparative Biochemistry IV’, Academic Press, New York, 1962. G. Bertrand and D. Bertrand. C.R. Hebd. Seances Acad. Sci., 1949, 229, 533. 54 55

‘’

‘’

The Elemental Constituents of Soils

101

of 5 mg kg-' for soils of the Russian plain, and 1 mg kg-' for Japanese soils.68 Recent work on 10 Scottish topsoils derived from different materials gives an average Cs content of 3.6 mg kg-' and a range of 1.7-5.7 mg kg-1,69 while 4 Brazilian soils had a mean content of 2.25 mg kg-' and a range of 0.6-6 mg kg-'.70 The average Cs content of soils can only be assigned, therefore, a tentative value of about 3 mg kg-'.

3 The Alkaline Earth Elements: Beryllium, Magnesium, Calcium, Strontium, and Barium Beryllium.-Geochemistry. Beryllium is more abundant in siliceous than in subsilicic rocks and is highly accumulated in alkalic rocks. The Be content of ultrabasic rocks averages < 0.25 mg kg-', while in granitic rocks it varies from 1 to about 30 mg kg-I, averaging about 5 mg kg-'. In intermediate rocks Be contents of more than 10 mg kg-' are produced by metasomatic processes. In granitic rocks micaceous minerals such as muscovite have relatively high Be contents of up to 50 mg kg-'.71 Weathering and Mobility. The most abundant Be minerals, beryl or chrysoberyl, are highly insoluble. During weathering, however, a fraction of the primary Be is mobilized and partly fixed in clay minerals. Clay minerals from weathered alkalic rocks can contain about 100 mg Be kg-', while bauxites and clay minerals formed by the weathering of Be-rich rocks contain up to 60 and 100 mg Be kg-', respectively. Be and Sr were lost during the weathering of the Carmenellis granite, C~rnwall.~* Soil Contents. L i ~ reports k ~ ~ the approximate concentration of Be in soils to be 6 mg kg-', while B ~ w e n reports '~ a median of 0.3 mg kg-I and a range of 0.01-40 mg kg-'. The crustal average for Be is 2.6 mg kg-1.75 A d e t a i l e d ' s t ~ d yof~ ~the pedochemistry of Be in soils of the Black Forest showed that the Be content increased from sand to silt to clay. The pedochemical behaviour of Be was found to be very similar to that of A1 and it was shown that Be was not incorporated into soil humus. The uptake of Be by spruce was very low even in soils of pH as low as 5. The total Be contents in thirteen profile subsoils ranged from 2.5 to 8.7, mean 4.6 mg kg-'.76 Total contents in 863 surface soils from the USA ranged from < 1 to 7, mean 1 mg kg-1,77in 14 surface soils from Japan 0.5 to 1.95, mean 1.32 mg kg-1,78

A. P. Vinogradov, 'The Geochemistry of Rare and Dispersed Chemical Elements in Soils', Consultants Bureau, New York, 1959. 69 A. M. Ure, J. R. Bacon, M. L. Berrow, and J. J. Watt, Geoderma, 1979,22, 1 . 'O C . C . Dantas and H. Ruf, Radiochim. Actu, 1975,22, 192. 7 1 K . H. Wedepohl (ed.), 'Handbook of Geochemistry', 11- 1/4, Springer Verlag, Berlin. " C. M. Rice, Mineral Mag., 1973, 39,429. l 3 D. J. Lisk, Adv. Agron., 1972, 24, 267. 74 H. J. M. Bowen, 'Environmental Chemistry of the Elements', Academic Press, London, 1979. l J S. R. Taylor, Geochim. Cosmochim. Acta, 1964, 28, 1273. 76 K. Keilen, K. Stahr, H. von den Goltz, and H. W. Zottl, Geoderma, 1977, 17, 3 15. 7 7 H. T. Shacklette, J. C. Hamilton, J . G. Boerngen, and J . M. Bowles, US Geol. Surv. Prof: Pap., GPO, Washington DC, 1971, No. 574-D. la T. Asami, J . Sci. Soil.Manure, Jpn., 1975,46,421. 68

102

Environmental Chemistry

and in 10 surface soils from Scotland 0.8 to 5.6, mean 2.7 mg kg-1.6y In 41 samples from eight Scottish soil profiles total Be ranged from < 5 to 30, mean 6.2 mg kg--1,3 while in 19 samples from four German profiles total Be ranged from < 3 to 10, mean 3.7 mg kg- ' (see ref. 8 I). On the basis of these analyses a tentative value of about 1.5 mg kg-I might be suggested as a mean soil content. Beryllium is accumulated in coals compared with detrital sedimentary rocks. Be in coals is generally inversely correlated with ash content suggesting that the Be occurs mainly associated with organic ~ e s i d u e s . ~Be ' is taken up by plants from high-Be soils but is generally accumulated in the roots and not readily translocated to other tissue^.'^ Be was found to be toxic to plants in an acid sandy loam but was not toxic in a soil containing free calcium carbonate.RoBe is toxic to humans and animals.

Magnesium.-Geochemistry. Magnesium is an important constituent of a large number of common rock-forming silicates i.e., olivines, pyroxenes, amphiboles, and micaceous and clay silicates. It also forms a large variety of carbonate minerals. Magnesium is relatively concentrated in the early crystalline precipitates in igneous rocks and there is a steady decrease in the Mg content through the calc-alkali series rocks ranging from gabbro to granite (and from basalt to rhyolite)." The crustal average for Mg reported by Taylor75is 2.33%. Weathering and Mobility. The most important Mg-minerals of igneous and metamorphic rocks which decompose during weathering are olivines, pyroxenes, amphiboles, biotites, and chlorites (the ferromagnesian minerals), and of sediments, dolomite, Mg-calcite, and chlorite. The ferromagnesian minerals are among the first to decompose during the process of rock weathering. Soil Contents. The total Mg content in 2723 soils from different parts of the world varies between 50 and 160 000 mg kg-' with a mean of 8262 mg kg-' (Table 5). For many soils, however, magnesium contents lie in the ranges of 0.2-0.8** or 0.04-0.9%74 Mg with a quoted median value of 0.5%.74Magnesium in soils exists in exchangeable, organically complexed, acid-soluble, and primary mineral forms. Most soil-Mg is in silicate minerals with relatively small amounts in the exchangeable and water-soluble forms. The Mg-containing silicate minerals include micas, micaceous clays, chlorites, vermiculites, and various ferromagnesian minerals, which are generally easily weathered and have a rather short life in soils. If not taken up by crops, labile Mg in the soil is vulnerable to leaching at a rate which depends upon the amount of soluble anions in the soil. Leached Mg may often accumulate in the subsoil. The combined losses by leaching and crop removal may be 1 1-55 kg Mg Some Mg, like K, may well be fixed in expanded 2 : 1 clays. Soils in temperate regions containing Mg-rich silicate minerals are, on average, higher in Mg than acid soils of the humid tropical regions. The relationship of Mg E. M. Romney and J. D. Childress, Soil Sci., 1965, 100, 210. R. J. B. Williams and H. H. Le Riche, Plant Soil, 1968.29,317. *'K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-1/12, Springer Verlag, Berlin. 82 R. C. Salmon, J . Sci. Food. Agric., 1963, 14, 605. l9

The Elemental Constituents ojSoils

103

Table 5 Magnesium soil contents (mg Mg kg-I) Soils Range 20 surface soils, New Jersey 240-1 1 670 18 soils, USA, 6 profiles 200-26 000 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 960- 18 600 108 soils, Ghana, 19 profiles (300--3000 195 soils, California, 50 profiles 1200- I 6 0 000 5 surface soils, North Carolina 89-302 37 soils, Poland, 13 profiles 6000- 17 500 863 surface soils, USA 50-100 000 9 1 soils from 14 profiles 201-6602 10 surface soils, UK and Malaya 600-4700 2 10 surface and subsoils, Finland 2000-23 000 698 soils, New Zealand, 168 profiles 97-51 923 44 surface soils, N.W. India 10 944-19 699 5 1 surface soils, Denmark 185 soils, Canada, 54 profiles 300-45 000 23 soils, Scotland, 4 profiles 2000-20 000 12 topsoils, S.E. USA 180-24 600 2723 Soils Overall Mean 8262 mg Mg kg-l

Mean 5 144 5940 I I 400 8380 950 13 000 18Y 11 200 9200 2355 25 10 10 400 653 I 15 280 1420 8 200 10 780 4750

R eJ a

b 4 92 6 C

d e 77 83

50 52

1' '9 h 1

.i k

a A. L. Prince, M . Zimmerman, and F. E. Bear, Soil Sci.. 1947, 63, 69; J . Connor. N. Shrimp, and J . C. F. Tedrow, ibid.. 1957, 83, 383: G . R. Bradford, R. J. Arkley, P. F. Pratt, and F. L. Blair, Hilgardia, 1967, 38, 54 I ; H . B. Rice. and E. J . Kamprath, Soil Sci. Soc. Am. Proc.. 1968, 32, 386; 'B. Dobrazanski and J . Glinski, Rocz. Glebozn.. 1971, 21, 365; 'A. J. Metson, E. J . Gibson, and R. Lee, N . Z . Soil Bur. Sci. Rep.. No. 31, 100 pp.: P. K. Sharma, B. P. Kaistha. B. R. Tripathi. and R. D. Gupta. Agrochimica. 1977. 21. 529: J. C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28. 81: ' J. A. McKeague. J. G. Desjardins. and M. S. Wolynetz. Agric. Canada. Ottawa 1979. LRRT Publ. 21: ' M . L. Berrow and R. L. Mitchell, Trans. R. Soc. Edinburgh: Earth Sci.. 1980, 71. 103: P. J. Lechler, W. R. Roy, and R. K. Leininger. SoilSci.. 1980. 130, 228

content to soil development and degree of weathering has been studied by Mokwunye and M e l ~ t e d . *The ~ silt and clay fractions in the soils chosen for this study contained more than 95% of the total soil Mg. Comparisons between temperate and tropical soils showed why highly weathered tropical soils are almost always deficient in Mg for plant growth. In a comprehensive study of Mg in New Zealand soils, the wide variations in total contents observed could be related to soil parent materials and degree of soil development as expressed in the genetic soil clas~ification.~~ Magnesium is essential to the growth of both plants and animals. It is an essential constituent of chlorophyll, but most of the Mg in plants is present in other forms. Magnesium is an activator of more enzymes than any other element; it is also involved in ion transport and cation balance in plants. Magnesium is also essential to the growth of humans and

Calcium.-Geochemistry. Calcium occurs in the upper continental crust of the earth to the extent of about 3.5% by weight and is fifth in the order of abundance

'' A. U. Mokwunye and S. W. Melstead. Cornmun. Soil Sci. Plan( Anal., 1973. 4. 397. 84

A. J. Metson and E. J . Gibson. N . Z . J . Agric. Res.. 1977. 20, 163.

'' J . B. Jones. jun., M. C . Blount, and S. R. Wilkinson, 'Magnesium in the Environment, Soils, Crops, Animals and Man'. Proc. Symp. Fort Valley. Georgia, USA. 1972. Fort Valley State College. 1972.

104

Env ironmen ta 1 Chemistry

(following 0, Si, Al, and Fe). It forms a large number of minerals, some of them being major constituents of rocks, including aluminosilicates, phosphates, carbonates, sulphates, and fluorides. Calcium aluminium silicate minerals formed at high temperatures, include plagioclase feldspars, pyroxenes, and amphiboles, while, of those formed at lower temperatures, calcite, aragonite, gypsum, dolomite, and high-Mg calcite are the most important. In sediments and sedimentary rocks Ca is mainly present in limestones or dolomites.86

Weathering and Mobility. The most important Ca-bearing minerals of igneous and metamorphic rocks that decompose during weathering are the plagioclases, pyroxenes, amphiboles, and epidote and in sedimentary rocks, calcite, dolomite, anhydrite, and gypsum. Experimental studies on the weathering of Ca silicates have produced solutions with a range of Ca concentrations, < 1-90, mean 15 mg kg-’, similar to those found in river waters. Surface sea water is normally saturated or nearly saturated with respect to CaCO, and a small amount of evaporation can cause precipitation.86 The geobiology of C a has been recently reviewed by Delwi~he.~~ Soil Contents. The mean total C a content in 1757 topsoil and soil profile samples from various parts of the world and derived from a wide range of parent materials is 1.96% with a range of 0.01-32% Ca (Table 6). The range of Ca contents in soils has been reported by B ~ w e n ’to~ be 0.07-50%, mean 1.5% Ca. Of those which are free of calcium carbonate, analyses have been reported showing values ranging from 0.086 to over 2%. Calcareous soil contents will vary from less than 1 to more than 25%. Extremely sandy soils in humid regions are frequently very low in total Ca content.88 Calcium occurs in soils ( a ) in primary mineral form, (b) as a constituent of inorganic compounds, (c) complexed or combined with organic matter, and (d) held by cation exchange. It is the major exchangeable cation in most soils and can be lost from soils by (i) leaching, (ii) crop uptake and removal, and (iii) erosion. In temperate humid conditions more Ca is lost by leaching than by cropping, and losses are replaced mainly by the application of lime. Calcium is a basic cation and thus neutralizes soil acidity. It also acts as a flocculator and this helps in maintaining the granular structure of soil particles.89 Lime is added to soils for several reasons which include (a) increasing the soil pH, (b) supplying Ca or C a and Mg, (c) obtaining optimum availability of nutrient cations, ( d ) increasing the availability of P and Mo, (e) increasing the rate of mineralization of nitrogen, and (f)reducing the activity of A1 ions in the soil to non-toxic levels. Calcium is essential to the growth of both plants and animals and plays a structural role as a constituent of cell walls in plants and as an essential component of the skeleton of many animals. The calcium ion is also involved in a number of metabolic processes. 8b

K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-2/20., Springer Verlag, Berlin. C. C. Delwiche, Commun. Soil Sci. Plant Anal., 1975, 6, 207. H. D. Chapman, ‘Diagnostic Criteria for Plants and Soils’, Univ. of California, Div. of Agric. Sci., 1966.

89

R. 0. McLean, Commun. Soil Sci. Plant Anal., 1975,6, 219.

The Elemental Constituents of Soils

105

Table 6 Calcium soil contents (% Ca) Mean Ref: Soils Range 4 1.32 134 topsoils, S.W. Pacific 92 0.983 trace-3.99 19 soils, USA, 4 profiles 0.46 0.107- 1.21 6 108 soils, Ghana, 19 profiles 7 139 soils Quebec, B horizons 3.69 77 2.40 863 surface soils, USA (0.0 15-3 2 0.327 50 0.01-0.96 10 surface soils, UK and Malaya 52 1.08 0.28-1.9 2 10 surface and subsoils, Finland a 1.39-16.65 5.65 4 soils, Canada b 0.347 5 1 surface soils, Denmark C 1.50 184 soils, Canada, 54 profiles 0.03-1 3.1 d 2.22 23 soils, Scotland, 4 profiles 1.O-4.6 e 1.72 0.02 1-1 3.29 12 topsoils 1757 Soils Overall Mean 1.96% C a “ R . D. Koons and P. A. Helmke, Soil Sci. SOC.A m . J., 1978, 42, 237; ‘ J . C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28, 81; J . A. McKeague, J. G. Desjardins, and M. S. Wolynetz, Agric. Canada, Ottawa 1979. LRRI Publ. 21: M. L. Berrow and R. L. Mitchell. Trans. R. SOC.Edinburgh: Earth Sci., 1980, 71, 103; P. J . Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130,238

Strontium.-Geochemistry. The bulk of the Sr in the earth’s crust occurs as a trace element dispersed in rock-forming and accessory minerals. The distribution of Sr(Sr2+, 1.13 A) in rock-forming minerals is controlled by its diadochy with Ca(Ca2+, 0.99 A) and K (K+, 1.33 A), and it commonly occurs in plagioclases and K-feldspars. The Sr levels found in other rock-forming minerals are considerably lower than those in the feldspars and are particularly low in micas. Among sedimentary rocks, limestones often contain high levels of Sr, up to 11 000 mg kg-’, whereas sandstones generally only contain 40-1 50 mg kg-’ and greywackes 100-400 mg Sr kg-’.90 The chief minerals of Sr are the sulphate and the carbonate and these occur as molecular deposits in sedimentary rocks or as veins possibly of hydrothermal origin. The crustal average Sr content is 375 mg kg-1.75 Weathering and Mobility. Losses of Sr during the weathering of rocks have been reported by Butler,” Short,92 and Rice,’* all indicating that Sr is a rather mobile element during rock weathering, particularly under conditions where decomposition of feldspars occurs. About 80% of the Sr in the rivers of the world is derived from the weathering of carbonates and sulphates, the remaining 20% being from silicates. Thus the major rock type involved in the Sr cycle is limestone.

Soil Contents. The range of Sr contents in topsoils and soil profile samples from various parts of the world and derived from a wide range of parent materials is <3--3500, with a mean of 278 mg kg-’ (Table 7). Of a quoted average abundance of 200 mg kg-’ up to about 20 mg kg-’ are soluble in neutral normal ammonium

K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-4/38, Springer Verlag, Berlin. J. R. Butler, Geochim. Cosmochim.Acla, 1953,4, 157. 92 N. M. Short, J. Geol., 196 1,69,534.

106

Environmental Chemistry

Table 7 Strontium soil contents (mg Sr kg-‘) Soils Range 40-800 41 soils, Scotland, 8 profiles 134 topsoils, S.W. Pacific 32-540 19 soils, USA, 4 profiles 93-920 360 soils, China, 11 1 profiles (3-3000 108 soils, Ghana, 19 profiles 139 soils, Quebec, B horizons 10-300 19 soils, Germany, 4 profiles <10-200 34 soils, Galapagos, 13 profiles 24-300 34 soils, Poland, 9 profiles 3-930 113 soils, Madagascar, 26 profiles <5-3000 863 surface soils, USA 46-496 110 soils, Cameroon, 18 profiles 26-234 260 topsoils, Wales 9-430 227 subsoils, Wales 75-3 5 00 66 soils, USSR, 19 profiles 200- 1 500 23 soils, Scotland, 4 profiles 7-186 12 topsoils, S.E. USA 30-500 173 soils, Canada, 53 profiles Overall Mean 278 mg Sr kg-’ 2735 Soils

Mean 282 226 234 270 126 1576 91 109 72 157 240 207 80 90 483 8 10 69 210

R eJ

3 4 92 U

6 7 8 9 b 22 77 23 C C

d e

f g

a C. L. Fang, T. C. Sung, and Bing Yeh, Acta Pedologica Sinica, 1963, 11, 130; J. Glinski, J. Melke, and S. Uziak, Rocz. Glebozn., 1968, 19, 73; R. 1. Bradley, C. C. Rudeforth, and C . Wilkins, J . Soil Sci., 1978, 29, 258; d B . K . Shakuri, Sou. Soil Sci., 1978, (lo), 189; ‘M. L. Berrow and R. 1,. Mitchell, Trans. R . SOC.Edinburgh: Earth Sci., 1980, 71, 103; ’P. J. Lechler, W. R. Roy, and R. J. Leininger, Soil Sci., 1980, 130,238; R J. A. McKeague and M. S. Wolynetz, Geoderrna, 1980, 24,299

acetate.93 The Sr contents in soils have also been reported to range from 4-2000, with a median of 250 mg kg-1.74The bulk of total Sr in profile samples is contained in the coarse and fine sand (2-0.02 mm) and in sand and silt fractions,95 probably in feldspar minerals, while very little Sr accumulated in the clay fraction.’ The retention of Sr by soils has been studied by Juo and Barber,94 who found that sorption increased with increasing pH of the system. Strontium is one of several elements that do not seem to be essential to the growth of any plant or of benefit to it. Strontium is also scarcely toxic to plants and no naturally occurring excesses of Sr in amounts sufficient to be toxic have been reported.88 There is no conclusive evidence that Sr is essential to animals,96 but it can be Barium-Geochemistry. In igneous rocks of the earth’s crust Ba usually does not form minerals of its own but is distributed among various silicate structures, mainly feldspars and micas. The most important substitution is for K owing to the nearly identical ionic sizes. The Ba content of igneous rocks normally increases as the SiO, concentration increases. Substitution for C a is observed in plagioclases, pyroxenes, and amphiboles, while apatite and calcite are the most important rock-forming D. J. Swaine, ‘The Trace Element Content of Soils’, Commonwealth Bur. Soil Sci., Tech. Communication No. 48, Commonwealth Agric. Bureau, Harpenden, England, 1955. 157 pp, 94 A. S. R. Juo and S. A. Barber, Soil Sci., 1970, 109, 143. 95 H. H. Le Riche and A. H. Weir, J . Soil Sci., 1963, 14, 225. 96 E. J. Underwood, ‘Trace Elements in Human and Animal Nutrition’, 4th Edn., Academic Press, London, 1977.545 pp. 93

The Elemental Constituents of Soils

107

Table 8 Barium soil contents (mg Ba kg-') Soils Range 4 1 soils, Scotland, 8 profiles 250-3000 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 322-2930 360 soils, China, 11 1 profiles 200-1 loo 108 soils, Ghana, 19 profiles < 10-10 000 19 soils, Germany, 4 profiles 10-2000 34 soils, Galapagos, 13 profiles < 100-440 80-4 15 34 soils, Poland, 9 profiles 24-4400 1 13 soils, Madagascar, 26 profiles 863 surface soils, USA 15-5000 110 soils, Cameroon, 18 profiles 188-748 7 soils, Brazil 545-925 43 soils, Bulgaria 366-2368 252-8 1 1 4 soils, Canada 23 soils, Scotland, 4 profiles 300-2000 12 topsoils, S.E. USA 37-648 1924 Soils Overall Mean 568 mg Ba kg-'

Mean 1243 49 6 I147 570 568 493 216 153 697 554 420 720 655 659 1052 250

R ef:

3 4 92 a 6 8 9 b 22 77 23 70 C

d e

f

a C. L. Fang, T. C. Sung, and Bing Yeh, Acfa Pedologica Sinica, 1963, 11, 130; J. Glinski, J. Melke, and S. Uziak, Rocz. Glebozn., 1968, 19, 73; 'M. Naidenov and A. Travesi, Soil Sci., 1977, 124, 152; R. D. Koons and P. A. Helmke, Soil Sci. SOC.A m . J., 1978, 42, 237; M. L. Berrow and R. L. Mitchell, Trans. R. SOC.Edinburgh: Earth Sci., 1980, 71, 103;'P. J . Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130, 238

non-silicates containing Ba. In sedimentary rocks and hydrothermal deposits barite is the least soluble and most abundant Ba mineral.97 The abundance of Ba in important masses of the earth's crust has been calculated by W e d e p ~ h l : ~the ' mean contents of igneous instrusive rocks being 728 mg kg-I, including: gabbroic rocks 246, granites 732, granodiorites and quartz diorites 873, and diorites 714 mg kg-'. The mean contents of sediments is 538 mg kg-', including: sandstones and greywackes 3 16, shales 546, and carbonate rocks 90 mg kg-'. The crustal average reported by Taylor" is 425 mg kg-'. Weathering and Mobility. Barium is released during the weathering of micas while feldspars are generally more resistant. In the naturally occurring weathering series biotite hydrobiotite --r vermiculite a decrease in Ba content from 3500 to 230 mg kg-' has been observed.97 In studies on trace elements in particle size separates from Scottish soils derived from igneous rocks it was found' that 60-90% of the total Ba was in the sands (2-0.02 mm), while similar studiesgs on some English soils showed that Ba occurred mainly in the sand and silt, probably in feldspars. +

Soil Contents. The range of Ba contents in topsoils and soil profile samples from various parts of the world and derived from a wide range of parent materials is < 10-10 000, mean 568 mg kg-' (Table 8). Most soils contain 10-3000 mg Ba kg-' of which up to about 30 mg kg-' is

97 98

K.H. Wedepohl ed., 'Handbook of Geochemistry', 11-4/56, Springer Verlag, Berlin. D. C. Bain, J . Soil Sci., 1976, 27,68.

Environmental Chemistry

108

extractable by neutral normal ammonium acetate.93 Very sandy soils composed largely of silica can contain as little as about 10 mg Ba kg-I, while the highest value which S ~ a i n reports e ~ ~ (3.3% Ba) comes from an area where barite was mined. Secondary barite is formed in soils under certain condition^.^^ There is no conclusive evidence that Ba performs any essential function in living organisms. Barium is accumulated in some plants, however, and brazil nuts often contain 3000-4000 mg Ba kg-I with no accumulation of Sr. Certain other plants species can accumulate large amounts of Ba from Ba-rich soils.97

4 Titanium, Zirconium, and Hafnium These elements, which fall in Group IVA of the Periodic Table, occur mainly in minerals that are generally resistant to weathering in normal soil conditions. Such minerals are normally more abundant in soils than in rocks. Titanium.-Geochemistry. Most minerals which contain Ti as a major constituent are either oxides or silicates. There are three oxides of Ti, rutile, anatase, and brookite which have the composition TiO,. Rutile is found widely in igneous rocks as a fine-grained accessory mineral and it also occurs extensively in metamorphic rocks. Anatase, occurring in sediments, is generally considered to be of secondary origin, while brookite in metamorphic rocks is rarer than rutile or anatase. Sphene (CaTiSiO,) is also present in igneous and some metamorphic rocks and is particularly abundant in granites. It is not as stable as rutile and is therefore less common in sedimentary rocks. Ilmenite (FeTiO,), like rutile, is found as fine grains in most igneous and metamorphic rocks. Many silicates in rocks, particularly micas, can also contain large amounts of Ti. The Ti oxides and ilmenite are very resistant to weathering and occur undecomposed in soils. If silicates containing Ti break down, the Ti released is transformed to anatase or rutile. Measureable dissolution of Ti from a volcanic glass at pH 3, but not at pH 5, 8, or 9 has been reported by Hoppe.*O' The geochemistry of Ti has been reviewed by Wedepohl.lo' Weathering and Mobility. The Ti-minerals, being very resistant to weathering in normal soil environments, usually accumulate in soils95* 102-104 and there is little indication of downward leaching of Ti through the soil profile during soil development. There is, however, good evidence of mobility of Ti in environments characterized by intense weathering over long periods of time as, for example, in tropical soils and laterites.106.lo' Evidence of Ti-solubilization has also been obtained from a Ti-rich peaty podzoL9* The clay formed in the A , horizon of this C. W. Childs, P. L. Searle, and A. V. Weatherhead N . Z . J. Sci., 1975, 18, 227. H-J. Hoppe, Chern. Erde, 1941, 13, 484. l o ' K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-2/22, Springer Verlag, Berlin. lo' R. Weyl, Pjlanzenerrraehr. Dueng. Bodenkde., 1952, 57, 135. Io3 H. H. Le Riche, Rep. Welsh Soils Discuss. Group, 1968, 9, 17. Io4 J. T. Hutton, in 'Minerals in Soil Environments'. ed. J. B. Dixon and S. B. Weed, Soil Sci. SOC.Am., Madison, Wisc., 1977, p. 673. Io5 G. D. Sherman, Soil. Sci.SOC.Am., Proc., 1952, 16, 15. J. T. Hutton, C. R. Twidale, A. R. Milnes, and H. Rosser, J . Geol. Soc. Ausr., 1972, 19, 31. lo' A. R. Milnes and J. T. Hutton, Search, 1974, 5 , 153. 99

I""

109

The Elemental Constituents of Soils Table 9 Titanium soil contents (mg Ti kg-') Soils

Range

18 soils, USA, 6 profiles 1000-6600 10 topsoils, New Jersey 3000-6 600 1000-25 000 4 1 soils, Scotland, 8 profiles 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 2 200-8 5 70 15 soils, Wales, 5 profiles 500-> 6000 1100-15 000 360 soils, China, 11 1 profiles 600-13 900 108 soils, Ghana, 19 profiles 139 soils, Quebec, B horizons 3300-16 500 34 soils, Galapagos, 13 profiles 1800-9900 6 1 soils, Burma, 17 profiles 650-34 000 1 13 soils, Madagascar, 26 profiles 1460-6 3 20 29 soils, Portugal, 6 profiles 300-15 000 863 topsoils, USA 12 soils, Scotland (60-16 400 19 1 soils, Canada, 8 1 profiles 400- 18 000 10 topsoils, Scotland 1900- 15 000 23 soils, Scotland, 4 profiles 2000-26 000 2 160-8270 12 topsoils, S.E. USA Overall Mean 509 1 mg Ti kg-' 2192 Soils

Mean 4 200 4 700 8085 72 10 4860

>4450 6500 3830 10 500 9350 43 10 7470 3004 3000 4730 4400 6400 10 960 4360

R ex 228 a 3 4 92 5 b 6 7 9 21 22 C

77 108

d 69

e

f

a A. L. Prince, Soil Sci., 1957, 84, 413; C. L. Fang, T. C. Sung, and Bing Yeh, Acta Pedologica Sinica, 1963, 11, 130; A. S. Coutinho, A. J. Das Texieira, E. M. De Sequeira, and M. D. Lucas, Agron. Lusit., 1973, 33, 257; J. A. McKeague, J. G . Desjardins, and M. S. Wolynetz, Agric. Canada, Ottawa, 1979, L R R l Publ. 21; e M . L. Berrow and R. L. Mitchell, Trans. R . SOC.Edinburgh: Earth Sci., 1980, 71, 103;fP. J. Lechler, W. R.Roy, and R.K. Leininger, Soil Sci., 1980, 130,238

soil, derived from chlorite schist, contained 7% Ti, almost entirely in the form of cryptocrystalline anatase. The A horizons of Scottish podzols often contain unusually large amounts (up to 140 mg kg-') of Ti extractable by edta. This form of Ti appears to be derived from the dissolution of Ti-minerals followed by Titanium has been found to be reprecipitation in situ in secondary form.108*109 subject to mobilization in four Canadian soils, thus making it unreliable as a weathering index."O Organic acids in soils may be involved in the mobilization of Ti as has been shown by Dumon.lll

Soil Contents. The mean Ti contents of 2192 soils on a world wide basis is calculated to be 5091 mg kg-' as shown in Table 9 with a range of <60-34 000 mg kg-'. ,~~ The distribution of Ti in soils has been well documented by S ~ a i n e Wells,4 Jackson,l12 Mitchell,' and Hutton.lo4The abundance in the lithosphere is 5700 mg kg-1,75and normal soils contain 150-25 000, median 5000 mg kg-1.74

Zirconium.-Geochemistry. Zirconium occurs in oxides and silicates in rocks as Zr4+ and the geochemistry of Zr is dominated by its lithophile nature and the behaviour of the commonest Zr mineral zircon (ZrSiO,). Zirconium also occurs as M. L. Berrow, M. J. Wilson, and G. A. Reaves, Geoderma, 1978,21,89. R. W. Fitzpatrick, J. Le Roux, and U. Schwertmann, Clays Clay Minerals, 1978, 26, 189. M. D. Sudom and R. J. St. Arnaud, Can. J. Soil Sci., 1971,51, 385. "'J. C. Dumon, Bull. SOC.Geol. Fr., 1976, 18, 75. 'lZ M. L. Jackson, in 'Chemistry of the Soil', 2nd Edn., ed. F. E. Bear, Reinhold, New York, 1964, p. 71.

Enuironmental Chemistry

110

the rare mineral baddeleyite, ZrO,. There is a general increase in Zr content in rocks following the sequence ultrabasic, basic, intermediate and acidic. Zircon occurs mainly in granitic rocks as small resistant zircon crystals but is also found in metamorphic and some sedimentary rocks. Zircon is relatively resistant to weathering but considerable amounts of Zr may be released during the weathering of other minerals which contain Zr as a minor component. Various estimates of the abundances of Zr in different rock types have been tabulated by Wedepohl'13 and these range from 115-240 mg kg- I . The abundance in the lithosphere is 165 mg kg-1.7s Because of the extreme immobility of the Zr it is unlikely that significant quantities will be accumulated in plant although it is concentrated in some coals. I I 5 Weathering and Mobifily. Because of the stable nature of zircon during the process of weathering and soil formation, Zr has been used as a weathering index in soils. Both quartz and Zr were found to be reliable indices against which to evaluate the movement of elements during pedogenic processes when the total contents in the >2p fraction were used."O Losses of 30--50% of the rock Zr, during the weathering of 12 soils derived from granite in Australia, have, however, been reported by Wild.116 Because of the possibility of solution of small crystals it was suggested that the larger grains of zircon of fine sand size may be a better index of profile changes than total soil Zr. Table 10 Zirconium sail contents (mg Zr kg- I ) Soils Range 134 topsoils, Finland < 10-3000 4 1 soils, Scotland, 8 profiles 70-> 1000 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 48-1 170 82 soils, Australia, 12 profiles 50-1 180 109 soils, Ghana, 19 profiles 20-2000 139 soils, Quebec, B horizons 34 soils, Galapagos, 13 profiles 62-540 1 13 soils, Madagascar, 26 profiles 20-1850 863 topsoils, USA < 10-2000 110 soils, Cameroon, 18 profiles 470-1054 26 I topsoils, Wales 60-970 227 subsoils, Wales 73-468 10 topsoils, Scotland 230- 1000 23 soils, Scotland, 4 profiles 20-400 Overall Mean 345 mg Zr k g - ' 2299 Soils

Mean 239 632 496 5 I6 263 275 960 227 363 240 676 265 28 5 604 208

R eJ:

a 3 4 92 1 I6 6 7 9 22 77 23 h h 69 122

" J . Lounamaa, Ann. Bot. SOC.Vunumo, 1956. 29; I, R. 1. Bradley, C . C. Rudeforth, and C . Wilkins, J . Soil. Sci., 1978, 29, 258.

K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-4/40. Springer Verlag, Berlin. R. R. Brooks. 'Geobotany and Biogeochemistry in Mineral Exploration'. Harper and Row, New York, 1972. ' I 5 V. M. Goldschmidt, 'Geochemistry', ed. A. Muir. Clarendon Press, Oxford, 1954. ' I 6 A. Wild. A us[. J . Agric. Res.. 196 1. 12. 300. 'I3

'I4

111

The Elemental Constituents of Soils

Soil Contents. The mean content of Zr in 2299 soils sampled world-wide was calculated (Table 10) to be 345 mg kg-' with a range of < 10-3000 mg kg-I. Other estimates of the abundance of Zr in the soils of the world by various authors have been summarized by W e d e p ~ h l . "A ~ typical range is 50-2000 mg kg-' with a mean of 300 mg kg-I. The range of Zr contents of 3 179 soil samples from the United States has been given at <30-2000 mg kg-' with a mean of 264 mg kg-'.l17 The mean content found in 10 Scottish soils69was 3.7 times the crustal abundance indicating an accumulation of Zr in soils relative to rocks.

Hafnium.-Geochemistry. The element Hf is so close to Zr in its chemistry and ionic size that it always accompanies Zr in nature. Hafnium is readily admitted into the structure of Zr minerals and, with a terrestrial abundance roughly one fiftieth of that of Zr, discrete Hf minerals are extremely rare. Zircon and baddeleyite are the most important sources of Hf and these minerals usually contain up to 2% Hf."* The crustal abundance of Hf is low at 3.0 mg kg-*,75but there is a general increase in content in the sequence ultrabasic + basic + intermediate granitic rocks, as is found for Zr. -+

Soil Contents. Most of the Hf, and Zr, in an eroding profile is preserved intact in detrital zircon and there can be no great changes in the Zr :Hf ratio of the alluvial products. Hafnium is in general, however, more basic, precipitates at a higher pH in most media, hydrolyses less readily and forms less stable complexes. For these reasons Hf does not follow Zr quite as closely in the supergene cycle as it does in magmatic processes. In sedimentary rocks the 1000 results available"* support the view of Vlasov that there is no marked accumulation of Hf in sedimentary rocks. . ~ suggested ~ ~ that Zr forms soluble humic complexes more readily Ronov et ~ 7 1have than Hf and is therefore more mobile in the presence of dissolved organic acids. The Hf contents of 10 Scottish topsoils derived from a wide range of geological parent rocks ranged from 4.4-34 mg kg-', mean 14.4 mg kg-'. The mean content is 4.8 times the crustal abundance value, which is consistent with the accumulation of Hf in weathered topsoils.69 The Hf contents of 40 Bulgarian soils mainly topsoils, were found to range between 1.95 and 18.7 mg kg-', mean 6.06 mg kg-1.5"4An overall range of Hf contents in soils of 0.5-34 mg kg-I, median 6 mg kg--', has been reported.74 Although Hf has been detected in plant and animal tissues'*' it appears that its presence is not essential. 5 Vanadium, Niobium, and Tantalum

Vanadium.-Geochemistry. The trivalent ion V3+ has an octahedral radius (0.6 1 A) almost identical with that of Fe3+ (0.63 A) so it follows iron in mineral formation and is found as a minor constituent in magnetite, pyroxene, amphibole, and I"

'IR I19

J. J . Connor and H . T. Shacklette, U.S. Geol. Suril. ProJ Pap.. 1975, No. 574-F. 168 pp. K . H. Wedepohl (ed.), 'Handbook of Geochemistry', I 1 5/72, Springer Verlag, Berlin. A. B. Ronov, E. E. Vainshtein, and A . M . Tuzova. Geochemistry, 1961, 3. 343. A. J . Erlank and J. P. Willis. Geochim. Cosrnochirn. Acta, 1964, 28, 1715.

En vironmen ta 1 Chemistry

112

biotite.121Vanadium contents are therefore higher in basic igneous than in granitic rocks. The average crustal content is about 135 mg kg-1.75

Weathering and Mobility. Vanadium is contained in the more easily weathered minerals of igneous rocks and as much as 20% of the total soil content can be released from such minerals by pedological weathering, particularly under poor drainage conditions.'22 In a study of rocks and their weathering products Butlerg1 found that V remains in the residual rock-forming and iron-bearing minerals and/or enters minerals in the silt or clay fractions. Vanadium can be adsorbed as the vanadyl cation (V0)2f, incorporated in clay mineral structures as suggested by Berrow et al.,lo8 adsorbed by iron oxide coating^,"^ or complexed by soil organic materials (see ref. 25 1). Soil Contents. The mean content for a world-wide series of soils, 2308 in number, calculated in Table 11, is 108 mg kgg' with a range of 3-1000 mg kg-*. The total V contents in soils normally fall within the range 20-500 rng kg-1,93 while a median content of 90 mg kg-' has been reported.74 The stability range of the Table 1 1 Vanadium soil contents (mg V kg-I) Soils

Range

Mean

Ref:

18 soils, USA, 6 profiles 10 topsoils, New Jersey 4 1 soils, Scotland, 8 profiles 134 topsoils, S.W. Pacific region 19 soils, USA, 4 profiles 15 soils, Wales, 5 profiles 360 soils, China, 111 profiles 33 surface soils, Georgia, USSR 108 soils, Ghana, 19 profiles 19 soils, Germany, 4 profiles 34 soils, Poland, 9 profiles 2 10 topsoils, Burma 68 soils, Burma, 17 profiles 1 13 soils, Madagascar, 26 profiles 64 soils, Poland, 22 profiles 863 surface soils, USA 110 soils, Cameroon, 18 profiles

9-96 11-1 19 15-300

56 54 140 132 194 112 92

a

-

30-5 20 15-200 16-166 70-1 80 3-500 300-1000 32-1 10

-

38-346 19-5 30 30-429 < 7-500 65-169 <26--162 9 soils, Brazil 0.8-200 12 soils, Scotland 66 soils, USSR, 18 profiles 14-380 50- 150 23 soils, Scotland, 4 profiles 18-263 12 topsoils, S.E. USA 2308 Soils Overall Mean 108 mg V kg-'

b 3 4 92 5 C

-

74 606 57 184 171 113 120 76 139 58 59 128 95 150

d 6 8 e

21 21 22

f 77 23

70 108

g

122 h

"J. Connor, N. Shrimp, and J. C. F. Tedrow, Soil Sci.. 1957, 83, 383; A. L. Prince, ibid., 1957, 84, 413; ' C. L. Fang, T. C. Sung, and Bing Yeh, Acta Pedologica Sinica, 1963, 11, 130; V. 1. Kobiashvili, Soobschch. Akad. Nauk. Gruzin S S R , 1964, 34, 67; J. Glinski, J. Melke, and S . Uziak, Kocz. Glebozn., 1968, 19, 73; f B . Dobrzanski and J . Glinski, ibid., 1971, 21, 365; B. K. Shakuri, Sou. Soil Sci.. 1978, (lo), 189; P. J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130, 238

K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-2/23, Springer Verlag, Berlin. M. L. Berrow and R. L. Mitchell, Trans. R. SOC.Edinburgh: Earth Sci., 1980, 71, 103. 123 R. M. Taylor and J. B. Giles, J . Soil. Sci., 1970, 21, 203. 122

The Elemental Constituents of Soils

I13

various V oxides in terms of pH and Eh124 suggest that the vanadyl cation (VO)2t may be an important form of V in many acid soils. The presence of organic acids may also be of importance since humic acid is able to reduce the metavanadate (V0,)- anion to the vanadyl (VO)'+ ~ a t i o n . ' ~Vanadium ~ , ' ~ ~ is also present in the soil in the form of van ad ate^,'^' while Bloomfield and Kelso 128 have shown that Mo, V, and U are mobilized as anions by anaerobically decomposing plant matter. Vanadium-fulvic acid chemistry has been studied using electron spin probe methods.129Vanadium is strongly accumulated in marine sediments and especially in bituminous formations where it occurs in porphyrin complexes. The V, Cr, and Ti contents of Russian soils and their distribution in profiles130have been discussed in terms of their soil parent materials and processes of soil formation. Sources of V in the atmosphere'31 and in the environment, and its effects on biological systems have also been d i s c ~ s s e d . ' ~ ~

Niobium.-Geochemistry. Biotite, amphiboles, and Ti-minerals are the major host phases of Nb in igneous rocks. The average crustal abundance of Nb has been calculated to be 20 mg kg-'.75*'33 Soil Contents. A range of 10 to 34, mean 24 mg kg-' was found in 20 lateritic soils from West Africa by Grimaldi and Berger.'34 Four other soils from near a N b mg kg-'. Total contents in 863 surface soils from the deposit contained 79-87 United States range from (10-100 mg kg-', mean 13 mg kg '. In a series of Scottish soils derived from a wide range of parent materials the Nb content is 25-300 mg kg-', mean 78 mg kg-', one soil developed from trachyte having the unusually high content of 300 mg kg-'. The mean soil content is nearly 4 times the crustal abundance figure suggesting that Nb accumulates in soil during weathering processes.6' Some American bauxites have been reported to contain high Nb contents averaging around 500 mg kg-'. The presence of citric, tartaric, and oxalic acids is known to produce a marked increase in the water solubility of both Nb and Ta because of chelation effects,'33 and Nb can migrate as soluble fulvic acid complexes.135The mean N b content of 139 B-horizon soils from Mont. St. Hilaire, Quebec, sampled at a depth of a few inches to 1 foot is 303 mg kg-' with a median of 240 mg kg-'. The N b contents of 34 soils from 13 profiles of Galapagos soils range from (6-33 mg kg-', mean 8.2 mg kg-1.9 An overall range for Nb in soils of 6-300 mg kg-', median 10 mg kg-', has also been rep~rted.'~.

124

H. T. Evans,jun. and R. M. Garrels, Geochim. Costnochim. Acta, 1958, 15, 13 I .

12'

A . Szalay and M. Szilagyi, Geochim. Cosmochim. Acta. 1967, 31, I .

j2'

IZs Iz9

I"

13*

B. A. Goodman and M. V. Cheshire, Geochirn. Cosmochim. Acta. 1975, 39, 17 1 1 . H. L. Cannon, Soil Sci., 1963, 96, 196. C. Bloomfield and W. I. Kelso, J . Soil.Sci., 1973, 24, 368. G. D. Templeton 111 and R. M. Chasteen, Geochim. Cosrnochirn.Acta, 1980,44, 74 I . Z. V. Patsukevich and M. I . Gerasimova., Moscow Unil?.Soil Sci. Bull.. 1976, 31, 64. W. H. Zoller, G. E. Gordon, E. S. Gladney, and A. G. Jones. 'Trace Elements in the Environment', ed. E. L. Kothny, Am. Chem. SOC..Washington DC, 1973, 31. US Natl. Acad. Sci. Committee on Biological Effects of Atmospheric Pollutants. 'Medical and Biological effects of Environmental Pollutants', Natl. Acad. Sci.. Washington DC, 1974. 1 I7 pp. K.H. Wedepohl (ed.), 'Handbook of Geochemistry', lI-4/4 1. Springer Verlag, Berlin. F. S. Grimaldi and 1. A. Berger, Geochim. Cosmochirn. Acfa. I96 1, 25, 7 1. N. A. Tyotina and V. B. Aleskovskii, Vopr. Mineral. Geokhim. Redkich Elernentoc., 196 I . 71.83.

114

Environmental Chemistry

Tantalum.-Geochemistry. Tantalum has almost the same ionic radius as Nb which causes close relationships in the crystal chemistry of the two elements. Biotite, amphiboles, and Ti-minerals are the major host minerals for Ta in igneous rocks and the Ta content in igneous rocks of the continental crust has been computed as 2.1 mg kg-l 1 3 6 and a crustal average of 2 mg kg-' reported by Taylor.75Tantalum occurs as Ta5+in natural compounds mainly replacing Fe or Ti, and on weathering is distributed between the residual primary minerals and secondary weathering products. Soil Contents. Few analyses of Ta in soils have been reported. Burstall and Williams137found 80 mg kg-' in a Ugandan soil but this was probably situated near an ore deposit. The Ta contents of 29 Bulgarian soils, mainly topsoils, range from 0.36 to 3.84 mg kg-', mean 1.19 mg kg-' (see ref. 504).

6 The Lanthanidesor Rare Earth Elements, and Yttrium and Scandium The Lanthanides and Yttrium.-Geochemistry. The lanthanides are not, strictly speaking, very rare (Ce, La, and Nd are more abundant in igneous rocks than Pb, Co, Sn, Mo, and W),138but are nevertheless commonly referred to as the rare earth elements (REE). Their chemical properties are closely similar and they behave as a coherent group in many geochemical processes. The decrease in ionic radius with increasing atomic number, the lanthanide c o n t r a ~ t i o n ,140 ' ~ ~is~reflected in a progressive gradation in chemical properties from La to Lu which leads to fractionation effects. Enhancements of heavy relative to light REE contents and vice versa can occur, for example, as a consequence of the greater stability of heavy REE complexes. This, in the past, has led to REE contents being considered in terms of a heavy REE, or yttrium group and a light REE or cerium group whose relative contents are expressed as the contents ratio C(La-Eu)/C(Gd-Lu, Y). Although the segregation into two groups is somewhat arbitrary and not usually so clearly defined,I4' minerals nevertheless occur with distinctive patterns of REE contents. The association of yttrium with the lanthanides, and with the heavy REE in particular, arises in the first place from its ~ it also resembles ionic radius which falls between those of Dy and H o . ' ~Chemically the heavy REE elements in many respects. Sometimes the element scandium, because of its position in the periodic table, is also associated with the REE but geochemically the similarities are few and Sc is treated separately below. Individual elements such as Eu (and perhaps Yb) can assume the divalent instead of the usual trivalent state of the REE in nature, and replacement of Ca2+ in plagioclase can, for example, give rise to Eu a n ~ r n a l i e s . ' ~Change * * ~ ~ ~of valence of Ce3+to Ce4$ also leads to differentiation and enrichment particularly in weathering K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/73, Springer Verlag, Berlin. F . H. Burstall and A. F. Williams, Analyst (London), 1952, 77,983. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/39. 57-7 I. Springer-Verlag. Berlin. ' 3 9 L. H. Ahrens, Geochim. Cosmochim. Acta, 1952, 2, 155. '41 J. Zeman, 'Kristalchemie Samrnlung Goschen Bd', 1220/ 1220a. Berlin, W. de Gruyter, 1966. 14' M. Fleischer, Geochim. Cosmochim. Acta, 1965. 29, 755. 1 4 2 M. J. Drake, Geochim. Cosmochim. Acta. 1975, 39. 55. 143 R. V . Morris. Geochim. Cosmochim. A d a . 1975. 39. 621. 13'

13'

The Elemental Constituents of Soils

115

Table 12 Average abundances of Y and REE in crustal igneous rocksa (mg kg-') Element La Ce

Pr Nd Sm Eu Gd Tb DY (Y) Ho Er Tm Yb Lu CY,La - Lu E(La - Eu)/C(Gd - Lu, Y)

Basaltic Rocks 6. I 16 2.7 14 4.3 1.5 6.2 1.1 5.9 32 1.4 3.6 0.60 3.2 0.55 599 0.98

Intermediate Rocks 31 60 7.4 31 6.2 1.3 6.8 1.1 6.1 35 1.5 3.9 0.65 3.8 0.62 ~196 2.3

Granitic Rocks 55 104 12 47 8 1.1 7.4 1. I 6.2 38 1.5 4.2 0.69 4.3 0.68 ~290 3.5

A. G . Herrmann; in 'Handbook of Geochemistry', ed. K . H. Wedepohl, 11-5/39, 57-7 I

products, hydrolysate minerals, and marine 145 Cerium can also be depleted in some basalts and granites.146Extensive use has therefore been made of the REE as tracer elements in the study of geochemical processes. The element promethium, Pm, is omitted because it does not occur in natural materials. The geochemistry of the REE has been reviewed by many author^.'^^-'^' Average contents of Y and REE in basaltic, intermediate, and granitic igneous rocks are listed in Table l2,I5l which highlights the increasing contents of the REE in acid igneous rocks and also the increasing ratio of the sum of the light REE, to that of the heavy REE and Yttrium (Gd-Lu, Y) from basic to acid igneous material. REE are also concentrated in pegrnatites, C = 7500 mg kg-', compared to an average C of 241 mg kg-' in igneous rocks.151 Weathering and Mobility. Dissolution occurs most readily by weathering of rocks at low pH, while at high pH the REE are precipitated and immobilized in the same way as a l ~ m i n i u r n . 'As ~ ~ a consequence of the higher stability of fluoride and E. D. Goldberg, M. Koide, R. A . Schmitt, and R. H. Smith, J. Geophj?s.Res., 1963, 68, 4209. J. H. Carpenter and V. E. Grant,J. Mar. Res.. 1967, 25, 228. '41 L. A. Haskin, F. A. Frey, and T. R. Wideman, in 'Origin and Distribution of the Elements'. ed. L. H. Ahrens, I n f . Ser. Monogr. Earth. Sci., 1968, 30, 889. 14' L. A. Haskin, F. A. Frey, R. A. Schmitt, and R. M. Smith, in 'Physics and Chemistry of the Earth', ed. L. H. Ahrens, Pergamon, Oxford, 1966, Vol. 7, p. 169. 14* J. L. Graf, jun., 'Rare earth elements as hydrothermal tracers during the formation of massive sulfide deposits and associated iron formations in New Brunswick', Ph.D. Thesis, Yale, University, 1975. 149 Yu. A. Balashov, 'Geochemistry of the Rare Earth Elements'. Nauka, Moscow, 1976. 'sI E. Roaldset, 'Mineralogical and chemical changes during weathering transport and sedimentation in different environments with particular reference to the distribution of yttrium and the lanthanoid elements', Ph.D. Thesis, University of Oslo. 1978. ''I K. H . Wedepohl (ed.), 'Handbook of Geochemistry'. 11-5/39,57-7 1 Springer Verlag, Berlin. l S 2 Yu. A. Balashov, A. B. Ronov. A. A. Migdisov, and N. V. Turanskaya, Geochem. Int.. 1964, 10, 951. 144

'41

116

Environmental Chemistry

carbonate complexes, the heavy rare earths are preferentially leached as indicated by Volga river water Burkov and PodporinaIS4on the other hand suggest that in an acid environment the lighter REE are more readily mobilized in the weathering of granites. Other Russian studies have indicated that no significant fractionation occurs in processes of weathering and sedimentation in arid environments but that in humid conditions enrichment of Y and REE in clay relative to sand fractions from decomposing feldspars etc. can occur. 1 5 2 , 1 5 5 , l S 6 Further recent studies of weathering and sedimentation processes have been made.150, 157-159 The REE can accumulate in weathered materials such as bauxite and laterite by coprecipitation with, or by adsorption on, Mn/Fe hydroxides 1 6 " , 1 6 1 and are enhanced in Jurassic Fullers earths.'62

Soil Contents. Few studies of the R E E and Y contents of soils have been made although an early reference quotes La and Y contents in soils of up t o 500 g ~ ~ 40 mg La kg-I and 50 mg Ce ton-' 163 (-500 mg kg-I), while B ~ w e nsuggests kg-' as median soil concentrations. Contents of La and Y in soils have been reported by a number of authors. The overall range and mean contents of La reported in Tables 13a and b, comprising 1019 samples in all, is 2.1-200 mg kg-', mean 4 1.2 mg kg-I. The overall range and mean contents of Y in 1490 soils is 5-2 13 mg kg-', mean 27.7 mg kg-' (Table 13b). More recent data for REEs in soils, with mean contents and ranges, are summarized in Table 13a. The contents of Sc in soils of highly diverse origin were found to correlate with those of Eu, Fe, and C o but not with La content^.'^^*'^^ Contents for Y and all the REE in a series of 10 Scottish arable topsoils developed on a wide range of parent materials have been determined by spark source mass s p e ~ t r o m e t r y Unlike .~~ the contents of rocks in Table 12, there was little evidence of increased total R E E and Y contents in soils derived from acid igneous parent materials compared to more basic materials. The highest contents occur in soils on metamorphic parent materials (granitic gneiss and quartz-mica-schist), and the lowest in a sandstone-derived soil. The potential value of REE and Y analysis of soils as a means of identifying parent materials, at least in the case of relatively young soils has been illustrated.'66 The enrichment of the REE in soil clays from weathered volcanic ash in Oregon, USA has been reported 16' and

Is' IS'

Is* 16" "I

IbJ lh4 I"

16'

Yu. A. Balashov and L. M. Khitrov, Geochem. Int,, 1967, 14,404. V. V. Burkov and Y. K. Podporina, Dokl. Acad. Sci. USSR, Earth Sci. Sect., 1967, 177, 214. A. B. Ronov, Yu. A. Balashov, and A. A. Migdisov, Geochem. lni., 1967, 14, 1. A. B. Ronov, Yu. A. Balashov. Yu.P. Girin, and R . Kh. Bratishko, Sedimentologv., 1974, 21, 171. Yu. A. Balashov and Yu. A. Kudinov, 'Novye dannye o mineralach SSSR, mineralogitesky muzey im', ed. A. E. Fersmana, vyp. 17, Izdatel'stvo Nauka, Moskva, 1966, p. 176. R. L. Cullers, L. G. Medaris, and L. A. Haskin, Geochim. Cosmochim. Acta. 1973. 37, 1499. Yu. A. Balashov and A. 1. Tugarinov, Geochem. J., 1976. 10. 103. S. Calliere, A . Maksimovic. and Th. Pobequin, 7'rar. ICSOAA, 1976, 13. 233. Z . Maksimovic. Trail. ICSOBA. 1976. 13. I . C. V. Jeans, R. J . Merriman. and J. G. Mitchell, Clay Mineral. 1977. 12, 1 I . R. L. Mitchell. Proc. Nutr. Soc., 1944. 1. 183. J. R. Kline, J. E. Foss, and S. S. Brar, Soil Sci. SOC.A m . Proc., 1969. 33. 287. J. R. Kline and S. S. Brar, Soil Sci.Snc. Am. Proc.. 1969. 33. 234. J. R. Bacon and A. M. Ure, Anal. Chim. Acia.. 1979, 105, 163. G. A. Borchardt, M. E. Harward, and G. E. Knox, Clays Clay Minerals, 1971, 19,375.

I17

The Elemental Constituents of Soils Table 13a REE mean soil contents (mg kg-I) Element No. of Soils La 77 Ce 924 Pr 10 Nd 920 Sm 72 Eu 72 Gd 10 Tb 57 Dy 10 Ho 10 Er 10 Tm 10 Yb 915 Lu 57

Ref. 70

Ref. a

Ref. b

73.8 107

36 76

36.6 50.5

13.4t 86$

36 7 804*

20.3 5.74 1.36

45$ 2.82f 0.74t

0.9

0.85

2.5 0.37

2.51 0.46

9.0 1.2

3.02

Overall Range (2.1-183) (9.8- 300) (3.4-12) (4.1-300) (0.6- 23) (0.1-2.6) (1.7-6.2) (0.1 1-1.71) (2.2- 12 .O) (0.39- 1.8 1) (1.4-6.2) (0.34-1.2) (0.04-50) (0.1-0.95)

Ref. 165f Ref. 69 Overall or Ref 7 7 t Mean

4.0$

34.7 67.9 6.46 29.3 5.77 1.23 3.50 0.84 5.66 0.80 3.01 0.62 4.43 0.5 1

37.4 84.2 6.46 43.6 5.98 1.28 3.50 0.85 5.66 0.80 3.01 0.62 3.94 0.46

* Not included in overall Mean and Range

Table 13b Additional lanthanum and yttrium values Soils Range Mean Lanthanum 41 soils, Scotland, 8 profiles
R ef. 3 5 77 122

C

3 9 77 d d 69 122 e

R . D. Koons and P. A. Helmke, Soil Sci. Soc. Am. J., 1978,42,237; * M. Naidenov and A. Travesi, Soil Sci., 1977, 124, 152; " J . R. Butler, J . Soil Sci., 1954, 5, 156; d R . J. Bradley, C. C. Rudeforth, and C. Wilkins, ibid., 1978, 29, 258; ' P . J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130,238

their distribution in clays discussed.'68,'69Enrichment of the REE, and Dy and Tb in particular, has been found in Fe/Mn concretions in New Zealand soils.'69 The elements have been reported to be exchangeable in soils.'7o The ratio of Zr and Y E. Roaldset, Bull. Gr. Fr. Argiles., 1974, 26, 201. P. C. Rankin and C. W. Childs, Chem. Geol., 1976, 18, 55. 'lo W. 0. Robinson, H. Bastron, and K. J. Murata, Geochim. Cosmochim. Acta, 1958, 14, 55. lb9

118

Environmental Chemistry

concentrations, Zr/Y, with an average value of 9.7 has been suggested as suitable, because of its constancy, for relating soils and sediments to their parent rocks."' While little evidence for their importance or essentiality for biological systems has been offered, the REE are accumulated by a few plants, notably hickory trees,'70.172--174 lichens and m o ~ s e s , ' ~and ~ , ' a~ yeast. ~ 177 Accumulation by some aquatic plant^"^^ 179 including species of water-lily, has been found, but this has not been confirmed in the water-lily, Nuphar lutea, in Scottish conditions."' Scandium.-Geochemistry. It is generally accepted that, despite the common membership of Sc, Y, and La in Group I11 of the periodic table, the geochemical behaviour of Sc is quite unlike that of Y and the lanthanides. Scandium is a dispersed element in the lithosphere and the great bulk of the element is contained in ferromagnesian minerals in igneous rocks, particularly pyroxenes. Only three rare minerals are known in which Sc occurs as a major constituent. Excluding rocks containing much olivine, which generally has a low Sc content, Sc in igneous rocks increases with decreasing content of SO,. The Sc contents of igneous rocks vary widely, those tabulated by WedepohlIx1 ranging from 0.6-200 mg kg-'. In common sedimentary rock types Sc is contained chiefly in shales, clays, greywackes, and argillites, generally in the range 10-25 mg Sc kg-', and is very low, usually only a few mg Sc kg-', in carbonate rocks and non-argillaceous sandstones. A relatively high Sc content is found in some bauxites, phosphorites, and residual deposits. In metamorphic rocks garnet is a host mineral for S C . ' ~The ' crustal average reported for Sc by Taylor75is 22 mg kg-I. Weathering and Mobility. The Sc3+ion, on release by mineral weathering, has a marked tendency to form complex ions of considerable stability. The most effective precipitant of Sc from solution is the phosphate ion, but the soluble complexes of Sc tend to hydrolyse or form insoluble basic salts. A possible linear relation between Sc and Fe3+ in sedimentary rocks has been indicated by Norman and Haskin.'** Scandium would be expected to coprecipitate with ferric oxide or to adsorb on collodial iron oxyhydroxides because the hydroxides of both Sc3+ and Fe3+ are quite insoluble. Soil Contents. The overall mean of 1056 soil analyses from various parts of the world reported in Table 14 is 10.1 mg Sc kg-' and Sc contents range from 0.5-55 mg kg-I. Earlier work reports the total Sc contents for 167 Scottish soil profile samples to range from < 10 to 25 mg kg-', mean 7.4 mg kg-1.93More recent data74 E. Murad, J . Soil Sci., 1978, 29, 219. W. 0. Robinson, R. Whetstone, and B. F. Scribner. Science., 1938. 87. 470. I J 3 1. D. Bornernan-Starinkevitsch and S. A. Borovik. C.R. Dokl. Acnd. Sci. U R S S , 1941, 30, 229. W. A . Thomas. Can. J . Bot., 1975, 53, 1159. H. T. Shacklette, U S Geol. Surzi. Bull., 1965. No. 1198 D. ' 7 6 0. Erarnetsa and I. Yliruokanen, Suorn. Kemisfil., 1971, 844, 121. V. T. Bowen and A. C. Rubinson, Nature (London), 195 I , 167. 1032. U. M. Cowgill. Appl. Specfrosc., 1973, 27. 5. 17' U. M. Cowgill, Geochim. Cosmochim. Acta. 1973. 37. 2329. A. M. Ure and J. R. Bacon, Geochim. Cosmochim. Acta, 1978,42,651. I * * K. H. Wedepohl (ed.). 'Handbook of Geochemistry', II-2/2 I., Springer Verlag, Berlin. I X 2J . C. Norman and L. A. Haskin, Geochim. Cosmochim. Acta. 1968, 32,93. "I

IJ2

119

The Elemental Constituents of Soils Table 14 Scandium soil contents (mg Sc kg-I) Mean Soils Range 3-20 8.2 4 1 soils, Scotland, 8 profiles 17.4 4-5 3 19 soils, USA, 4 profiles 1.3-4 1.0 10.7 13 soils, world-wide 5.1-1 0.9 8.0 33 soils, USA, 3 profiles 10 863 surface soils, USA (5-50 3.1-5.9 4.3 8 soils, Ontario 7.3 0.5-18.0 9 soils, Brazil 15.5 3.4-55.4 43 soils, Bulgaria 5.0-1 7.7 10.5 4 soils, Canada 8.3 23 soils, Scotland, 4 profiles (5-20 Overall Mean 10.1 mg Sc kg-' 1056 Soils

R ef: 3 92

165 164 77 a 70 b C

122

A. Chattopadhyay and R. E. Jervis, Anal. Chem., 1974, 46, 1630; M. Naidenov and A. Travesi, Soil Sci.. 1977, 124, 152; '~ R. D. Koons and P. A. Helmke, Soil Sci. Soc.Am. J., 1978,42,237

shows the range of contents to be 0.5-55 mg Sc kg-I, with a median of 7 mg kg-I. Little information is available on the behaviour of Sc in pedological processes, although in four profiles from the USA, Shortg2found that the soils showed a net gain in Sc with respect to the original parent rock composition. Scandium contents in soils have been found to correlate with those of C O . ' ~Sc~is probably adsorbed by colloidal clay particles and by hydrous A1 and Fe oxides during pedological weathering and there is little evidence that it moves down the profile due to l e a ~ h i n gIt. ~shows little or no accumulation in natural waters. 181 Scandium is not known to be essential to the growth of plants or animals and natural toxicities of the element are unknown. It is a trace constituent of various marine organisms and of plants. The ashes of peat, coal, and crude oil contain significant amounts of S C . ' ~ ~

7 Molybdenum and Tungsten Geochemistry.-Molybdenum and tungsten are transition metals separated by the lanthanide elements and in consequence of the lanthanide contraction are of almost identical radius. Their chemical behaviour is therefore very similar, with isomorphism playing an important role. Their distribution does, however, differ in some geological materials because, for example, the solubility of the sulphide of tungsten is greater than that of molybdenum. The geochemistry of Mo and W is reviewed by W e d e p ~ h l . ' ~I x~4, In oxidizing conditions Mo occurs as Mo"' and in reducing conditions commonly as Mo", but all oxidation states Mo"' to MoV1can occur in nature. The common ore mineral of Mo is the sulphide, molybdenite, and M o can occur with sulphides of Cu, Fe, Pb, and Zn, whereas the more soluble tungsten sulphide is seldom found. Tungsten minerals are almost always tungstates of which the most important are the C a (Scheelite) and the Fe/Mn (Wolframite) tungstates. A Mo-analogue of Scheelite also occurs.

184

K. H. Wedepohl (ed.), 'Handbook of Geochemistry'. 11-4/42. Springer-Verlag, Berlin. K. H. Wedepohl (ed.), 'Handbook of Geochemistry'. 11-5/74, Springer-Verlag, Berlin.

120

Environmental Chemistry

Mol-ybdenum. The similarity in size permits substitution of Mo for Al, Fe, Ti, and perhaps Si. Molybdenum is enriched in minerals containing Ti4+ and F e 3 + and particularly in W-minerals. Average contents for M o are 1.4 mg kg-' in basic rocks, 1 mg kg-I in acid rocks, and 2 mg kg in sedimentary rocks.'xs Black bituminous shales, however, have much higher average contents estimated at about 70 mg kg-'.IR3 In granitic rocks some 80% of the Mo occurs in the feldspars with significant amounts in biotite.'86 The crustal abundance of Mo is quoted by Ronov and Yaroshev~kii'~' as 1.2 mg kg-l and by Taylor7sas 1.5 mg kg-'. Tungsten. Tungsten contents tend to increase from ultrabasic rocks, with average contents 0.1-0.8 mg kg-I, and basic rocks with 0.5-1 mg kg-', to granitic rocks with 1.5 mg kg-'.lS4 The abundance of W in sedimentary rocks is of the same order as in igneous rocks, and unlike Mo, it is as abundant in sandstones as in shales.'" In igneous rocks W is associated with granitic materials and with quartz veins in pegmatites, where it often occurs with cassiterite, molybdenite, arsenopyrite, and bismuth minerals. Substitution of W for N b and T a accounts for the high contents of W in Nb- and Ta-minerals. Weathering and Mobility.-Molybdenum. Molybdenite oxidizes fairly readily through a soluble intermediate, MoO,SO, to a final product H , M o O ~ which ' ~ ~ can migrate easily, with subsequent loss either by leaching or by adsorption on Al, Fe, and Mn oxides as well as in organic rich sediments, coals, etc.lx6Molybdenum is mobilized in soils by aerobically decomposing plant material and can be fixed by colloidal organic materials at pHs of 1-4.12R The importance of the pH of humic materials in mobilizing Mo has been discussed by S ~ i l a g y i . ' ~ ~ Tungsten. Weathering of wolframite and scheelite is slow. Placer deposits of resistate material left by weathering are found and the brittleness of these two minerals is adduced to explain their dispersal as fine-grained sedimentary complexes at slightly acid pH.l9' Soil Contents.-Molybdenum. Average soil contents for 2568 soils have been calculated at 1.92 mg Mo kg-' in Table 15, a value in close agreement with the average for 2 mg kg-' reported in earlier corn pi la ti on^.^^$^^ Reported values, Table 15, for normal soils, range from 0.07-28 mg Mo kg-I. Soil contents are enhanced, however, in soils developed on black shales, which can contain up to 100 mg Mo kg-1.'923193For example, mean contents for 177 soils of this type in England A. P. Vinogradov, Geochemislry, 1962, 7, 641. S. M. Manskaya and T. Z. Drozdova, 'Geochemistry of Organic Substances', Pergamon, 1968, p. 221. 18' A. B. Ronov and A. A. Yaroshevskii, in 'Encylopedia of Geochemistry and Environmental Sciences 4A', ed. R. W. Fairbridge, Van Nostrand-Reinhold, New York, 1972. 188 U. Wiendl, 'Zur Geochernie und Lagerstatterkunde des Wolframs', Diss. Tech. Univ. Clausthal., 1968. N. I. Chitarov and L. A. Ivanov, Geochim. Coll., 1937, 1, 13. 19" M. Szilagyi, Geochemistry., 1967, 12, 1489. I9'S. Doucet, Bull. SOC.Fr. Mineral. Cristallogr., 1966, 89, 120. 1 9 * P. Doyle, W. K. Fletcher, and V. C. Brink, Can. J . Bol., 1973, 51,421. 193 I. Thornton and J. S. Webb, 'Symposium on Copper in Farming', Imperial College, Copper Development Association, London, 1975, p. 3.

In'

IE6

12 1

The Elemental Constituents of Soils Table 15 Molybdenum soil conterits (mg M o kg-I) Range

Soils Compilation normal soils up to 1965 Soils, Poland Soils, Poland 24 soils, India, 863 topsoils, USA Topsoils, USSR Soils, Serbia 227 soils, Brazil, 28 profiles Soils, Germany 134 topsoils, S.W. Pacific

-

Mean 2.00

0.65-3.50 Trace-8.5 0.5-2.4 <3-1 0.5 1-1.17 0.60-5.15 0.12-5.74 0.58-5.73 -

360 soils, China, 1 11 profiles 0.1-7.0 108 soils, Ghana, 19 profiles (3-20 82 topsoils, Victoria, Aust. 0.3-9.3 195 soils, California, 50 profiles 0.22-27.5 44 I surface soils, USSR 27 surface soils, Uttar Pradesh, India 62 soils, Spain, 22 profiles 0.07-5.0 64 soils, Poland, 12 profiles 0.08-1.79 32 organic soils, Sri Lanka 0.25-3.50 844 topsoils, USSR 48 soils, USSR, A horizons 0.75-2.5 8 1 soils, Brazil, profiles 0.09-5.84 90 soils, Ukraine 2568 Soils Overall Mean 1.92 mg Mo kg-

Ref: a* b* 197* 198* 77* 199* C*

d* 2.54 2.2 2.94 2.98 2.50 1.46 2.65 0.62 0.35 2.10 1.78 1.99 1.40 2.13

e* 4

f 6 g h 1

211 j k 203 I rn

d 200

* Not

included in overall Mean ‘Handbook of Geochemistry’, ed. K. H. Wedepohl, 11-4/43. Springer-Verlag, Berlin; N . Piotrowska, Pam Pulawski, 1967, No. 30. 99: < N . Markovic, Arch. Pooopriu. Nauk., 1975. 28, 67: 0. C. Battaglia, P. R. Furlani, and J. M. A. S. Valadares, Ann. 1st Brazil Congr. Soil Sci., 1976. Brazil SOC. Soil Sci., Campinas, 107; 0. Horak, Bodenkuliur. 1977. 28, 405; f C . L. Fang, T. C. Sung. and Y . Bing, Acta Pedologica Sinica. 1963, 1 I, 130; R. M. McKenzie, Ausl. J . Exp. Agric. Anim. Husb., 1966, 6, 170; G. R. Bradford, R. J . Arkley, P., F. Pratt, and F. L. Blair, Hilgardia. 1967, 38, 541: ‘ N . G. Zyrin, Sou. Soil Sci., 1968, (7), 933; ’E. Barragan Landa and J. 1. Herrero, An. EdaJol. Agrubiol., 1973, 32, 89; W. Dzieciolowski and Z. Kocialkowski, Rocz. Glebozn., 1973, 24 241; ‘ Y u . N. Zborishchuk and N. G. Zyrin., S O P .Soil Sci., 1974, (6), 209; S. Kh. Dekhkankhodzhayeva and Ye. K. Kruglova, ibid., 1975, (7). 314 a

averaged 7.1 m g Mo kg-’.193Molybdenum is probably present in soils principally as a complex anion but it c a n exist in exchangeable cationic forms produced b y reduction with organic matter128. or in association with clay-sized mineral particles in organo-mineral complexes.196 Total Mo contents are well correlated with the fine fractions’973198 but not with the organic content in Indian soils.IYRIts distribution in soil fractions shows a maximum content in clay fractions and a minimum in coarse sand fractions.199 C l a y soils have higher M o contents than sandy, calcareous, or siliceous soils.2ooCorrelation of Mo contents with Fe contents 1947195

194

19’

A. Szalay, Geochim. Cosmochim. Acta, 1964,28, 1605. A. Szalay, Ark. Mineral. Geol., 1969, 5, 23.

R. L. Mitchell, in ‘Trace Elements in Soils’, Tech. Bulletin Min. Agric. Fish. Food, HMSO, London, 1971, No. 21, p. 8. K . Czarnowska, Rocz. Nauk. Roln., Ser. A , 1968,94, 5 1 I . 19R T. Balaguru and A. D. Mosi, Madras, Agric. J., 1973, 60, 147. I’’ S. Mirchev and E. Fotakieva, Pochuozn. Agrokhim., 1975, 10, 3. 2oo A. Ye. Gorbacheva, Sou. Soil Sci., 1976, (8), 33 I . 196

122

Environmental Chemistry

in fine earth fractions has been demonstratedlZ3 and in acid soils Mo can be immobilized by adsorption on Fe and other oxides.201 Soil contents are generally closely related to those of the soil parent materialzo0 and in soil profiles are usually evenly distributed.202Subsoils tend to be somewhat richer in Mo than surface horizons203especially in freely or imperfectly drained soils although not in poorly drained soils.196Some accumulation has been observed ' ~ ~ in humic horizons of in as well as in C horizons in c h e r n o z e r n ~and forest (Taiga) soils.2o4 Molybdenum has considerable biological importance in agriculture, both as an essential element in plants and, also, because of its toxic effects in animals. It plays a part in the fixation of atmospheric nitrogen by soil ~ ~has . ~ ~been ~ organisms and in the reduction of nitrate in plant m e t a b ~ l i s r n . It shown to increase soil phosphate activity.206 Excessive Mo in herbage induces copper deficiency disease in animals96*207*208 and interactions with S in animal metabolism208 and in plant uptake209 occur. Deficiencies in plants grown in acid soils have been attributed to AI/Mo and Mn/Mo antagonisms2I0in the soil. From the agricultural point of view interest is principally in the available soil Mo contents and a wide body of literature exists in this area which is not germane to the present work. Total Mo nevertheless correlates well with available Mo,211v212 and various soil extractants have been assessed as a measure of availability in toxic soils.213 Molybdenum availability increases with soil pH 196*2053214-216 and with increased organic carbon content.'96 High Mo uptake can occur at low pH in highly organic soils.216The identification of areas of potential Mo toxicity by the analysis of soils and stream sediments has been d i s c ~ s s e d . ' ~An ~*~ assessment ~' of Mo reserves in Slovakian soils has been made.z18The analysis of wood from pine tree has been shown to be more successful than soil analyses219for prospecting. The use of peat analysis for this purpose is discussed by Peterson220and by Quin and Brooks221 who quote contents in plant-ash of up to 1500 mg Mo kg-I. The agricultural role of Mo in soils, plants, and animals has been reviewed by several workers. 193,208,222,223. B. H. Smith and G. W. Leeper, J . Soil Sci., 1969, 20, 246. P. G. Aderikhin and N. A. Protasova, Agrokhimiya, 1970, No. 9, 109. 203 V. Pavanasasivam and F. S. C. P. Kalpage, J . Indian SOC.Soil. Sci., 1974, 22, 352. Io4 A. S. Sharova, G. A. Sklyarov, and K. A. Artem'eva, Agrokhimya, 1970, No. 8, 94. 205 E. Gorlach, Acta. Agrar. Silvestria., 1967, 7, 79. 206 S. P. Gorbanov, Pochvozn. Agrokhim., 1975, 10,97. *O' J. Kubota, V. A. Lazar, G. H. Simonsen, and W. W. Hill, Soil Sci. SOC.Am. Proc., 1967, 31, 667. 2ow N. F. Suttle, in 'Trace Elements in Soil Plant Animal Systems', ed. D. J. D. Nicholas and A. R. Egan, Academic Press, New York, 1975, p. 271. *"'J. Delas, C. Juste, and J. Tauzin, Sulphur lnsr. J., 1972, 8, 14. 'lo B. T. Cheng and G. J. Ouellette, Soils Ferf., 1973, 36, 207. 2 1 ' S. G. Misra and K. C. Misra, J. Indian SOC.Soil Sci., 1972, 20, 193. 212 S. Singh and B. Singh. J. Indian SOC.Soil Sci., 1966, 14, 19. 2 1 3 C. Williams and I . Thornton, Plant Soil.,1973, 39, 149. *14 J. S. Grewal, D. R. Bhumbla, and N. S. Randhawa, J. Indian Soc. SoiiSci.. 1969, 17. 27. ' I J 1. Thomson, I. Thornton, and J. S. Webb, J . Sci. Food Agric.. 1972, 23, 87 1. 216 T. Walsh. M. Neenan. and L. B. O'Moore, Nature (London). 1953.9, 1120. 2 1 7 I. Thornton, G. F. Kershaw. and M. K. Davies, J . Agric. Sci.. 1972, 78, 157. 2 1 B C. Juran and M . Grodovsky, Ved. Pr. Vvsk. Ustavu. Rasil. Vyroby Piestanoch., 1966, 4, 115. 'I9 Anon.. Nature (London), 1969, 223, 888. 220 P. J. Peterson, Sci. Progr, 197 I , 59. 505. 2 2 ' B. F. Quin and R. R. Brooks. N.Z. J . Sci., 1972, 15, 308. 222 P. Sequi, Agrochimica, 1972, 17, 119. 223 V. V. Koval'skii and G. A. Yarovaya, Agrokhimiya, 1966. No. 8,68. 'OL

202

The Elemental Constituents of Soils

123

Tungsten. The average content of W in ten soils on different parent materials was found to be 1.13 mg kg-I with a range of 0.50-2.7 mg kg-16' but little other information is available for soils from unmineralized areas. Higher concentrations have been found in soils in mineralized areas and W ranged from 1-130 mg kg-I Soil contents ranging from 1-1800 mg W kg on soils developed on have been found in regions with scheelite ore bodies.225Few firm conclusions are available on the distribution in profiles although some suggestion of concentration Studies with W isotopes have in B horizons in Indian soils has been demonstrated that the movement of W up and down soils is dependent on the presence of high concentrations of exchangeable Na and K.79 Solubility and availability of W is lower at low pH.225Like Mo, it probably exists in soils mainly in anionic forms, is associated with Fe and Mn oxides and is concentrated largely in the finer soil fractions. A range of 0.5-83 mg W kg-', median 1.5 mg kg-', has been reported by B ~ w e n . ~ " Although biological effects have been demonstrated for W, the evidence suggests that W is not essential to plants but can substitute for Mo in its N-fixation role when Mo is absent or deficient.226

8 Chromium, Manganese, Iron, Cobalt, and Nickel Chromium.-Geochemistry. During magmatic fractionation, Cr is incorporated in the early formed minerals and is closely associated with Mg and Ni in igneous rocks. Chromite, FeCr204,most commonly occurs in ultrabasic rocks but many reports suggest that a major portion of the Cr in basaltic magmas can also be incorporated into the early crystallized Cr-rich spinel. Olivines are generally poor in Cr but pyroxenes, amphiboles, and micas can be relatively rich. Chromium is most sensitive to magmatic fractionation and there exists, therefore, a wide range of Cr contents in different rock types. Generally, however, the abundances of Cr in rocks are: ultrabasic rocks 2600 mg kg-', basalts 100-300 mg kg-', diorites and andesites 25-100 mg kg-', granites and rhyolites 1-30 mg kg-'. The average content of 3904 shales is 83 mg kg-' and of 21 19 sandstones 27 mg kg-', whereas various groups of limestones had average contents ranging from 1-16 mg Cr kg-1.227The crustal average for Cr has been reported to be 100 mg kg-I, with basalts averaging 200 mg kg-I and granites 4 mg kg-1.75 Weathering and Mobility. Because Cr3+ closely resembles A13+ and Fe3+ in its chemical properties and ionic size, it will behave similarly to these ions during weathering processes, and will tend to be concentrated in clays. The average Cr content for recent shallow-water clay sediments is 60 mg kg-' and for sandy sediments is 26 mg kg-'.227 Soil Contents. The mean content of some 3290 soils sampled world-wide was calculated (Table 16) to be 84 mg Cr kg-I with a range of 0.9-1500 mg kg-'. The range of Cr contents in soils has also been reported by B ~ w e to n ~be~5-1500 mg Y. G. Dekate, Econ. Geol., 1967, 62 556. B. F. Quin and R. R. Brooks, Plant Soil., 1974, 41, 177. 226 H. J . M. Bowen and P. A. Cawse, Nature (London), 1962, 194, 399. 227 K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-3/24, Springer-Verlag. Berlin. 224

225

En vironmen ta1 Chemistry

124

Table 16 Chromium soil contents (mg Cr kg-’) Range Soils <3-300 106 topsoils, Finland 7-5 1 18 soils, USA, 6 profiles 7-300 36 soils, Scotland, 8 profiles 129 topsoils, S.W. Pacific 9-226 19 soils, USA, 4 profiles 15-400 15 soils, Wales, 5 profiles 16-3 10 360 soils, China, 1 1 1 profiles 10-300 109 soils, Ghana, 19 profiles 6 0 - 1000 19 soils, Germany, 4 profiles 16-6 1 34 soils, Poland, 9 profiles 2 10 topsoils, Burma 60-3 80 68 soils, Burma, 17 profiles 20-930 1 13 soils, Madagascar. 26 profiles 13-333 64 soils, Poland, 22 profiles 1-1500 863 topsoils, USA 49-32 1 1 10 soils, Cameroon, 18 profiles 4-1 10 6 soils, Brazil 14-38 39 topsoils, Canada 10-46 296 topsoils, Ontario 36 1 topsoils, Sweden 0.9-5 7 55- 1085 37 soils, Bulgaria 12-189 4 soils, Canada 66 soils, USSR, 18 profiles 10-300 10-150 23 soils, Scotland, 4 profiles 3 1-691 12 topsoils, S.E. USA 10-100 173 soils, Canada, 53 profiles 3290 Soils Overall Mean 84 mg Cr kg-’

Mean 135 23 133 192 69 192 103 82 339 33 160 138 210 53 53 177 35 23 22 16 258 76 69

Ref:

44 129 43

122 k 1

a 228 3 4 92 5 b 6 8 C

21 22 d 77 23 70 e

.f g

h I

j

“ L . Lounamaa, A n n . Bot. SOC. Vanamo, 1956, 29: b C . L. Fang, T. C. Sung, and Yeh Bing. Acta Pedologica Sinica, 1963, 11, 130; “ J . Glinski. J . Melke. and S. Uziak, Rocz. Glebozn., 1968, 19, 73; B. Dobrzanski and J . Glinski, ibid.. 1971, 21. 365; ’ J . G. Mills and M. A. Zwarich, Can. J . Soil.Sci., 1975, 5 5 , 295;’ R. Frank, K. Ishida. and P. Suda. ibid.. 1976, 56, 18 I ; A. Anderson, Swed. J . Agric. Res., 1977, 7. 7: M. Naidenov and A. Travesi, Soil Sci.. 1977, 124, 152: R. D. Koons and P. A. Helmke, J . Soil Soc. A m . , 1978. 42. 237; ’ B . K . Shakuri, Sot!. Soil Sci., 1978, (10). 189; P. J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130, 238; ‘ J . A. McKeague and M. S. Wolynetz, Geoderma. 1980. 24. 299

kg-’ with a median of 70 mg kg-I. In some podzolic soils, particularly those developed on serpentine rocks, the C r contents of the A horizons are lower than the B horizons suggesting the possibility of leaching of Cr from the upper horizon where weathering is most intense.3*206,228 In soils derived from basic rocks, much of the Cr is present in chromite, magnetite, and ilmenite, which are resistant to weathering and accumulate in sand fractions. In soils low in Cr, however, Cr released by weathering is concentrated in the clay fraction. Several workers have found that soluble Cr, added to soil either as Cr3+or chromate, becomes strongly

22R

J. Connor, N. Shrimp. and J . C. F. Tedrow. Soil Sci..1957, 83, 65.

The Elemental Constituents of Soils

125

bound in the soil in insoluble forms,229-23z which are mainly hydrated oxides of Cr3+ mixed with, or occluded in, iron oxides. Chromate Cr can be reduced to Cr3+ more rapidly in acid than in alkaline soils. A review of the work on Cr in the soils of Poland has been prepared by Boratynski et al.233 Numerous studies have been made that report the total Cr contents in soils . Cr ~ in ~these~soils~ is often ~ ~ developed on ultrabasic serpentine ~ o c ~ sTotal of the order of 0.3% but can exceed several per cent. Because of this, serpentinic soils have been excluded from Table 16. A comprehensive review of the ecology of serpentine soils has been prepared by Proctor and W0ode11.~~~ Plants absorb small amounts of Cr from the soil and sensitive analytical methods now consistently detect Cr in plants and animals. Some high Cr levels reported in plants can, however, be attributed to soil ont tarn in at ion.^^'-^^^ Some authors have attributed the limited vegetation on serpentine soils to Cr-toxicity, whereas others have demonstrated an increase in the yield of potatoes following addition of Cr to the Although Cr is not known to be essential to plant life it is essential to the growth of animals.96

Manganese.-Geochemistry. Manganese is found in naturally occurring minerals as the ions Mn2+ or Mn3+ but in magmatic and metamorphic systems is usually in the divalent state. Divalent manganese, replacing ferrous iron, magnesium, and other ions of similar size in silicates and oxides, is partially oxidized during chemical weathering of magmatic, metamorphic, and some sedimentary rocks. Tetravalent manganese forms oxides of very low solubility at the site of rock decomposition and a small fraction is mobilized as Mn2+. The low concentrations of manganese in surface water indicates a restricted mobility of this element during rock weathering. Manganese correlates with ferrous ions in igneous rocks at an average Mn/Fe ratio of about 0.0 15-0.02. As rock-forming ferromagnesian minerals contain much more manganese (1000-4000 mg kg-I) than feldspars (10-50 mg kg-’) and quartz (< 10 mg kg-’), basic and ultrabasic rocks contain more manganese than granitic rocks. Wedepohl 243 estimates that the manganese contents of various rock types are: ultrabasics 1050, basalts 1300, gabbros 1100-1300, granites 350, rhyolites 620, limestones 550, gneisses and mica schists 600 mg kg-I with an overall average content of 773 mg Mn kg-’ in the upper continental crust. A crustal R. J . Bartlett and J. M. Kimble, J . Environ. Qua!., 1976, 5 , 383. P. R. Shewry and P. J. Peterson, J . Ecol., 1976, 64, 195. 2 3 1 E. E. Cary, W. H. Allaway, and 0. E. Olson, J . Agric. Food. Chem., 1977, 25, 305. 232 J. H. Grove and B. G . Ellis, J . Soil Sci. SOC.Am., 1980, 44, 238. 233 K. Boratynski, E. Roszyk, and M. Zietecka, Rocz. Glebozn., 1972.23, 285. 234 B. E. Kilpatrick, Colorado Sch. Mines Quart., 1969,64, 323. 23s E. M. de Sequeira, Agron. Lusit., 1969, 30, 115. 236 S. Suzuki, N. Mizuno, and K. Kimura, Soil Sci. Plant Nufr., 197 1, 17, 195. 237 A. J. Anderson, D. R. Meyer, and F. K . Meyer, Aust. J . Agric. Res., 1973, 24, 557. 238 J. Lee, R. R. Brooks, R. D. Reeves, C. R. Boswell and T. Jaffre, Plant Soil.,1977, 46, 675. 239 M. J. Wilson and M. L. Berrow, Chem. Erde, 1978, 37, 18 1. 24n J. Proctor and S. R. J. Woodell, Adu. Ecol. Res., 1975,9, 255. 24’ M. L. Berrow and J. C. Burridge, in ‘Inorganic Pollution and Agriculture’, M A F F Ref. Book 326, HMSO, London, 1980, p. 159. 242 L. 0. Tiffin, in ‘Micronutrients in Agriculture’, ed. J. J. Mortvedt, P. M. Giordano. and W. L. Lindsay, Soil Sci. SOC.Am. Inc.. Madison, Wisc., USA., 1972, p. 199. 243 K . H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-3/25, Springer Verlag, Berlin. 229

230

~

~

126

Environmental Chemistry

average for manganese of 950 mg kg I, with an average for basalts of 1500 mg kg-' and for granites 400 mg kg I, have also been r e p ~ r t e d . ' ~ Weathering and Mobilitjj. Manganese released by rock weathering in oxidizing systems at low temperatures forms various oxides and hydroxides, often of poor crystallinity which are thus difficult to identify. In addition to elements like Ba, K, Li, Na, Pb, and Zn which can be major constituents of manganese oxide minerals, appreciable contents of Co, Mo, TI, V, and W have been recorded in manganese oxides of certain contental deposits. Deep-sea manganese nodules have specifically accumulated Co, Cu, Ni, Mo, Pb, T1, and Zn, the first three elements being in economically attractive concentrations (0.5 to 3%).243 Because of the low solubility of manganese in oxidizing systems at pH levels near or a little above neutrality, small changes in E h or pH can be important in the mobilization of manganese during weathering. In aqueous systems Mn2+is the most important valence state and exists as a hexa-aquo ion similar in size to the Fe(H,O)it ion. The availability of manganese and iron in aqueous systems has been investigated by Hem244who found that ferrous iron is more easily oxidized than the manganese ion under most natural Eh-pH conditions. The solubility of Mn2+ in natural waters under reducing conditions may be limited by the presence of carbonate, sulphide, or hydroxide. Because of its size, Mn2 fits into the calcite and, more easily, into the dolomite structural lattice. As a result dolomite contains about 20 times as much Mn as co-existing calcite. Primary calcite precipitated from normal sea water contains manganese concentrations as low as 20 mg kg-I. The high mean value of 550 mg Mn kg in limestones obtained by Wedepohl is influenced by a few samples with relatively high manganese contents. I t is suggested that the higher manganese abundances in carbonate rocks probably result from diagenetic mobilization of manganese under reducing conditions.243 Soil Contents. The overall mean content of 8354 soils detailed in Table 17 is 761 mg Mn kg-', with a range of < 1-18 300 mg Mn kg-'. The total manganese content in most soils has been reported to be in the range 200-3000 mg kg-'.93

Table 17 Manganese soils confents (mg Mn k g - ' ) R arige

Soils 44 soils, E. Canada, 8 profiles 134 topsoils, Finland 18 soils, USA, 6 profiles 124 topsoils, Queensland 122 soils, Australia, 20 profiles 4 1 soils, Scotland, 8 profiles 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles I5 soils, Wales, 5 profiles 360 soils, China, 1 1 1 profiles 108 soils, Ghana, 19 profiles 139 soils, Quebec, B horizons 34 soils, Galapagos, 13 profiles I95 soils, California, 50 profiles 244

250-1 380 30-6000 20-5 20 6-3800 39- 1000 50- 7000 -

20-3040 1000-3000 63-2 100 30-3000 -

920-4400 34-3320

J. D. Hem. Geol. SOC. Am.. Spec. Pap. 1972. No. 140. p. I7

Meat?

R eJ:

800 1487 198 1159 363 1898 2333 926 2 180 840 90 7 1680 2232 632

a 382 228 19 h 3 4 92 5 C

6 7 9 d

127

The Elemental Constituents of Soils Table 17 (cont.) Range

Soils 34 soils, Poland, 9 profiles 2 10 topsoils, Burma 68 soils, Burma, 17 profiles 160 topsoils, India 427 topsoils, USSR I 13 soils, Madagascar, 26 profiles 29 soils, Papua-New Guinea, 6 profiles 19 1 soils, Colorado, 37 profiles 57 soils, India, 10 profiles 40 soils, India, 7 profiles 64 soils, Poland, 22 profiles 74 soils, United Arab Rep. 6 1 soils, New Brunswick, 13 profiles 863 topsoils, USA 44 soils, India, 1 1 profiles 110 soils, Cameroon, 18 profiles 5 1 soils, Israel, 12 profiles 36 soils, Israel, 10 profiles 62 soils, Spain, 32 profiles 64 soils, Poland, 12 profiles 30 soils, Japan, 8 profiles 10 topsoils, India 1204 topsoils, European USSR 9 soils, Brazil 296 topsoils, Ontario 46 soils, Poland, 9 profiles 36 1 topsoils, Sweden 26 1 topsoils, Wales 23 1 subsoils, Wales 4 soils, Canada 1182 topsoils, Ukraine 2 16 soils, Louisiana, 72 profiles 5 1 topsoils, Denmark 23 soils, Scotland, 4 profiles 12 topsoils, S.E. USA 173 soils, Canada, 53 profiles 8354 Soils

390-

1065

-

178-1450 700-2300 50-18 300 104-8 700 68- 1340 200-449 135- I005 44-3000 250-1938 <80-2900 < 1-7000 247-840 1 1 1-2165 34-903 172-7 12 20- 1 600 26-590 199-4890 421-1998 -

20-6 14 90-3000 63- 1600 12-1840 46--8423 54-79 14 550-910 25-2229 300- 1500 3 1-1936 I 00- 1200

Mean

R eJ

643 587 688 1227 952 1612 21 I8 385 31 1 456 702 1248 586 560 439 663 53 1 442 337 100 1270 938 652 24 7 530 456 405 1230 95 8 705 65 8 395 279 800 336 520

e 21

f

505 22 g 12 h i

j k 252 77 1 23

m ?I 0

P 16 4 r 70 S

I U

U

v U’ Y

253

Y 122 805 Z

Overall Mean 761 mg Mn kg-’

‘I J. R. Wright, R. Levick, and H. J. Atkinson, Soil Sci. SOC. Am. Proc.. 1955, 19, 340: R. M. McKenzie. CSIRO (Australia) Div. Soils 1960. Div. Report 6/60, 17 pp: (‘C.L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica, 1963. 11, 130: “ G . R. Bradford. R. J. Arkley. P. F. Pratt. and F. L. Blair. Hilgardia, 1967, 38, 541; (’J. Glinski, J. Melke, and S. Uziak. Rocz. Glebozn., 1968, 19. 73: ’0. P. Sharma and D. A. Shinde, J. fndian Soc. Soil Sci., 1968, 16. 65; g P . Bleeker and M. P. Austin, Aust. J . Soil Res., 1970, 8. 133: h M . Singh, Agrochimica. 1970, 14, 565; ‘ P . N. Takkar, Geoderma. 1970. 3. 215: ’B. Dobrzanski and J. Glinski. Rocz. Glebozn.. 1971. 21, 365: k A . H. El-Damanty. H. Hamdi, and A. A. Orabi., UAR J . Soil Sci., 1971, I f . 7; ‘R. Mishra and B. R. Tripathi, Indian J. Agric. Sci..1972, 42, 585; S. Ravikovitch and J. Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric.. 1972. 1-12, pp. 20: “ J . Navrot and S. Ravikovitch. Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric.. 1972, 13-20, pp. 20: “ E . Rarragan Landa and J. 1. Herrero, An. Edafol. Agrobiol., 1973. 32. 89: W. Dzieciolowski and Z. Kocialowski, Rocz. Glebozn., 1973, 24, 24 1: F . La1 and T. D. Biswas. J . Indian Sac. Soil Sci..1973. 21.455: Yu. N. Zborishchuk and N. G . Zyrin, Sov. Soil Sci., 1974. (6), 209; ’ R. Frank. K. Ishida. and P. Suda, Can. J . Soil Sci.. 1976. 56, 181; ‘ A . Sapek and P. Sklodowski, Rocz. Glebozn., 1976, 27, 137: ‘A. Andersson. Swedish J . Agric. Res., 1977. 7. 7: ” R. 1. Bradley. C. C. Rudeforth, and C. Wilkins. J . Soil Sci.. 1978. 42. 237: R. D. Koons and P. A. Helmke. J . Soil Sci. Soc. A m . , 1978. 4 2 237: N. K. Krupskiy, L. P. Golovina. A. M. Aleksandrova. and T. I. Kisel, Sou. Soil Sci., 1978. (6). 670; J. C. Tjell and M. F. Hovmand. Actu Agric. Scarzd.. 1978, 28,8 1 : ‘ J. A. McKeague and M. S. Wolynetz, Geoderma, 1980, 24, 299

128

Environmenlal Chemistr-v

From a world-wide sampling, Vinogradov68 reports a mean of 850 mg Mn kg-’, whereas B ~ w e n ’reports ~ a range of 20-10 000 with a median of 1000 mg kg-’. Manganese in soil can be divided into two main forms (a) the manganese present in primary minerals, the nature of which will depend upon the type of parent material undergoing weathering and (b) the manganese present in secondary minerals, which are important because of their high surface activity. The oxidation of manganese in soils is rapid and may be accomplished by oxygen from the air, or by biological means. The commonest forms of mineralized manganese in soils are birnessite, lithiophorite, and hollandite, while todorokite has also been The manganese dioxides in soils have a high sorption capacity and they can accumulate large amounts of other ions from the soil solution. The sorption of cobalt is particularly strong and it can be fixed in a form unavailable to plants. The sorption of trace elements on to manganese and iron oxides and also on to clay minerals has recently been extensively reviewed by Jenne.246 The mobility of manganese in soils and its availability to plants are related to the solubility of manganese oxides and are, therefore, very dependent on oxidizing conditions and pH. Under slightly acid soil conditions below a pH of about 6, manganese is sufficiently soluble to make deficiencies unlikely. As the soil becomes more acid, leaching of manganese occurs and it is translocated from A to B horizons. In acid podzols, particularly those developed on coarse textured parent material, manganese is mobilized and precipitated at considerable depth in the form of manganese pans which can contain several per cent manganese. Such pans form well below the depth at which iron pans are formed and manganese is generally more susceptible to downward movement than iron.247*248 In fine-textured soils, which generally have a higher than average pH, mobilized manganese is often precipitated in soil B horizons as concretions or nodule^.^^*-^^^ Manganese is generally not strongly complexed by soil organic matter251but can often accumulate in profile A , horizons, probably as MnO,, in a gradient of increasing oxidation.252The distribution of manganese in soil profiles can show great variability since it depends on soil type and on such factors as soil drainage, pH, and oxidation-reduction condition^.'^.^^^ The biological oxidation of manganese as it affects availability to plants has also been comprehensively studied (see ref. 324). The manganese cycle in soils and the factors affecting uptake of manganese by plants 254 and availability to animals 2 5 5 have been reviewed. A survey

R. M. McKenzie, Z . Pflanzernaehr. Dueng. Bodenkde., 1972, 131,22 1. E. A. Jenne, in ‘Symp. on Molybdenum in the Environment’, ed. W. Chappel and K. Petersen, 1977, Vol. 2, p. 425. 24’S. Gotoh, Soil Sci. Plant Nutr., 1976, 22, 335. 248 C. W. Childs and D. M. Leslie, Soil Sci., 1977, 123, 369. 249 D. H. Yaalon, C. Jungreis, and H. Koyumidjisky, Geoderma, 1972, 7, 71. K. Norrish, in ‘Trace Elements in Soil-Plant-Animal Systems’, ed. D. J. D. Nicholas and A. R. Egan, Academic Press, London, 1975, p. 55. 2 s 1 M. V. Cheshire, M. L. Berrow, B. A. Goodman, and C . M. Mundie, Geochim. Cosmochim. Acfa, 243 24h

1977,41. 113 1.

2J2E.W. Presant, Geol. Suru. Can. Bull., 1971, No. 174,93. 253 J. E. Sedberry, H. Karim, and B. J. Miller, Commun. Soil Sci. Plant. Anal., 1978, 9, 389. 2s4 B. T. Cheng, Agrochimica, 1973, 17, 84. 2 J 5 D. J. Horvath, Geol. SOC. Am. Bull., 1972, No. 83,451.

The Elemental Constituents of Soils

129

of investigations on manganese in Polish soils has been carried-out by Boratynski et a1.256

Manganese is essential to the growth of both plantsESand animals.96Deficiencies of manganese in crops such as cereals and legumes are often found on neutral or alkaline soils, usually above pH 6.5, whereas under strongly acid conditions plants can suffer from toxicity owing to excessive uptake of manganese. In biological systems manganese functions as an enzyme activator and participates in physiological redox systems.

Iron.-Geochemistry. The geochemistry of iron is largely determined by the ease with which its valence state changes in response to physicochemical conditions. Iron commonly occurs in the form of oxides, sulphides, phosphates, and in silicates in rocks. Iron, together with magnesium, plays an important role in the formation of a number of rock-forming silicates such as olivines, pyroxenes, amphiboles, and micas. In contrast, the framework-type silicates like quartz, feldspars, and zeolites contain only trace amounts of iron. The geochemical behaviour of iron at the earth’s surface is intimately linked to the chemistries of 0, S, and C. These three elements, along with iron and manganese, are the most abundant of the elements which exhibit variable valence states and, as a result, important redox reactions with iron occur. Atmospheric oxygen reacts with primary ferrous minerals during weathering to form ferric oxides (hematite, goethite). In sediments, organic carbon is utilized by bacteria to reduce ferric oxides to ferrous compounds and dissolved sulphate to sulphide. In the presence of sufficient dissolved sulphide, iron sulphides may form. If sulphide is low, oxidized carbon in the form of dissolved carbonate may react with ferrous iron to form siderite. If both dissolved sulphide and carbonate are low and silica is abundant, iron silicates, such as glauconite may form. In this manner silicon, although not a variable valence state element, is also involved in the sedimentary geochemistry of iron.257The crustal average for iron has been reported to be 5.63% with an average for basalts of 8.56% and for granites 2.70%.”. Weathering and Mobility. Weathering of igneous rocks often involves the attack by C0,-rich solutions on silicate minerals to form new aluminosilicates (clays) together with dissolved cations, silica, and bicarbonate in solution. During the weathering of ferromagnesian minerals, ferrous iron is released from crystal lattices and upon oxidation forms ferric oxides such as hematite (Fe20,) or ferric oxyhydroxides such as goethite, (a-FeOOH) and lepidocrocite (YFeOOH), the latter being restricted to gleyed soils. Ferric oxides formed by weathering are invariably very fine-grained and form coatings on clays and sands or react with organic matter. Because clays have a greater specific surface area than sands, they accumulate more iron and, thus, iron is concentrated in fine-grained sediments. This is one of the reasons why shales are often richer in total iron than sandstones. Hematite is the stable form of iron expected under high pH and aerobic conditions where little or no decomposable organic matter is present and this accounts for the colour of many so called red 2J6 K.

Boratynski, E. Roszyk, and M. Zietecka, Rocz. Glebozn., 1971,22, 205.

En u ironmen ta I Chemistry

130

Soil goethites are very fine grained, as small as 0.02 pm, and hence, like manganese oxides, can contribute significantly to the surface activity of soils.25o Soil Contents. The total iron contents in 3 13 1 soils from various parts of the world are detailed in Table 18 and range from 0.01-21.0%, with a mean of 3.20%. The total iron in soils has been reported to lie within the range 0.2-55%, with a median content of 4.0%.74In temperate latitudes iron released by pedological weathering is often leached from A horizons and precipitated in underlying B horizons. The results of this process are particularly evident in acid podzol profiles where the breakdown of iron-containing minerals in the A horizon leads to the formation of a bleached 'ash-grey' layer, while the translocated iron can often accumulate strikingly as a thin iron pan in the B , horizon. Such iron pans can contain up to 50% total iron.25RIn brown earths, where the pH is generally higher than in podzols, the translocated iron is precipitated through the B horizon as Table 18 Iron soil contents (5% Fe) Soils Range 18 soils, USA, 6 profiles 0.23-7.0 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 1.2- 1 3.4 108 soils, Ghana, 19 profiles 0.9 1-2 1.O 139 soils, Quebec, B horizons 195 soils, USA, 50 profiles 1.03- 10.3 13 topsoils, world-wide 0.2-19.2 19 1 soils, Colorado, 3 7 profiles 0.26-6.75 1.75-4.50 40 soils, India, 7 profiles 37 soils, Poland, 13 profiles 1.01-2.87 61 soils, New Brunswick, 13 profiles 0.09-7.26 863 topsoils, USA 0.01-> 10.0 62 soils, Spain, 22 profiles 0.06-8.10 10 topsoils, India 1.02-4.99 37 soils, New Zealand, 10 profiles 1.4-1 1.2 296 topsoils, Ontario 0.26-3.89 43 soils, Bulgaria 0.09- 1.37 260 topsoils, Wales 0.56-8.7 5 230 subsoils, Wales 1.05- 13.7 4 soils, Canada 1.5 1-5.99 5 1 topsoils, Denmark 285 soils, Canada. 8 1 profiles 0.1-12.2 23 soils, Scotland, 4 profiles 1.2- 13.8 12 topsoils, S.E. USA 0.4 1-10.6 3131 Soils Overall Mean 3.20% Fe

Mean 2.99 6.86 5.92 4.8 1 6.45 3.72 4.52 1.81 3.53 I .99 3.32 2.50 1.39 2.7 1 4.16 1.45 0.45 4.06 4.4 1 3.83 0.93 2.6 6.57 5.15

R ef 228 4 92 6 7 a 165 12 b C

252 77 d e

f R 5 04

h h i j

k 122 805

G. R. Bradford, R. J . Arkley, P. F. Pratt. and F. L. Blair. Hilgardia. 1967, 38. 54 1 : P. N. Takkar, Geoderma. 1970. 3, 215; " B. Dobrzanski and J. Glinski. Rocz. Glebozn., 1971, 21, 365; "E. Barragan Landa and J. I. Herrero. A n . Edufol. Agrohiol.. 1973, 32, 89; F. La1 and T. D. Biswas. J . Indian SOC. Soil Sci., 1973, 21. 455:'L. F. Molloy and L. C. Blakemore, N . Z . J . Sci., 1974. 17. 233: Y R .Frank, K. Ishida, and P. Suda, Can. J . Soil Sci.. 1976, 56, 181: R. I. Bradley, C. C. Rudeforth. and C. Wilkins, J . Soil. Sci.. 1978. 29. 258: ' R. D. Koons and P. A . Helmke, J . Soil Sci. Soc. Am.. 1978, 42. 237: 1 J. C. Tjell and M. F. Hovmand. Acfa Agric. Scanti., 1978. 28, 81: J. A. McKeague. J . G. Desjardins. and M. S. Wolynetz, Agric. Canada, Ottawa. 1979. LRR 1 Publ. 21

257 258

K. H. Wedepohl. 'Handbook of Geochemistry', 11-3/26. Springer Vcrlag. Berlin. R . A. Goodman and M. L. Berrow. J . Phys.. 1976. 37, C6. 849.

The Elemental Constituents of Soils

131

surface coatings giving rise to red or yellowish-brown colours. Under poor drainage conditions, where anaerobic conditions prevail, reduction of iron take.; place which gives rise to the green, blue-green, or grey colours characteristic of gley soils. Under the intensive weathering conditions of tropical climates, secondary iron can accumulate in surface horizons forming lateritic soils. A recent review of iron in soils has been prepared by Dixon and Weed.259 Iron is essential to the growth of both plants and animals. In green plants it is a constituent of chloroplasts and is necessary for photosynthesis. When plants lack sufficient iron, chlorosis, or yellowing of the leaves takes place and this usually arises on high pH soils where the availability of iron in the soil has been reduced. Iron is also an essential constituent of haemoglobin which is involved in the transport of oxygen in the blood of humans and animals.

Cobalt.-Geochemistry. There are no common rock-forming minerals of Co but it frequently occurs with Ni, replacing Mg and Fe in a number of minerals. In basic and ultrabasic rocks there is a strong correlation between the Co and the sum of the Fe and Mg contents. In granitic rocks the correlation of Co is primarily with Mg and because Mg generally follows the content of Ca, there is a higher Co concentration in high-Ca granitic rocks than in corresponding low-Ca rocks. In the sequence from ultrabasic rocks to basalts and andesites there is a decrease in the Ni:Co ratio from 13.3 to 2.8 to 1.5. In sediments and sedimentary rocks the distribution of cobalt closely follows that of iron. Minerals such as quartz, feldspar, and pure calcium carbonate generally have very low cobalt contents (less than 0.5 mg kg-I). Rocks such as arkoses and greywackes can have considerably higher Co concentrations which usually reflect the amounts of mafic minerals which they can contain. No major redistribution of C o takes place during metamorphism, and shales and schists often contain similar Co contents. Gneisses are indistinguishable from granites in the close association of Co with Mg.260The crustal average for Co has been reported to be 25 mg kg-I with an average for basalts of 48 mg kg-' and for granites 1 mg kg-1.75 Weathering and Mobility. Cobalt is relatively easily mobilized during weathering and unlike nickel does not form residual minerals. The distribution of cobalt after release by weathering is dependent upon the type of clay being formed and on the formation of iron and manganese oxide phases. In the weathering of igneous rocks, the cobalt, which is a constituent of readily-weathered minerals, passes chiefly into argillaceous rocks such as shales. These, in general, have a cobalt content similar to the weighted mean content of all types of igneous rocks, some 24-40 mg kg-'.*'j' In an examination of 779 black shales from North America a median content of 10 mg kg-I was found,262this low content suggesting that Co is not accumulated in organic matter. Cobalt released by weathering is strongly accumulated in soils,

259

J. B. Dixon and S. 0. Weed, (ed.), 'Minerals in Soil Environments', Soil Sci. SOC. Am.,Madison,

Wisc.. USA, 1977. K . H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-3/27, Springer-Verlag, Berlin. R. L. Mitchell, Proc. 1X Int. Symp. 'Trace Elements in Plant Nutrition', Punta Ala. 1972, p. 521. 262 J. D. Vine and E. B. Tourtelot, Econ. Geol., 1970, 65, 253. 260

Environmental Chemistry

132

and in deep sea manganese nodules,26"which are now being manganese exploited for cobalt and other metals.

Soil Contents. The total cobalt contents of 5504 samples of soil detailed in Table 19 range from 0.3-200 mg kg-I with a mean of 12.0 mg kg-'. A range of 0.05-65 mg Co kg-' with a median content of 8 mg kg-' has been reported by B ~ w e n and '~ a range of 1-40 mg kg-' by S ~ a i n e . ~ ~ The chemistry of soil cobalt and its relationship to the uptake of cobalt by plants has been discussed by Tiller, Honeysett, and H a l l ~ w o r t h ,Mitchell,26' ~~~ and McKen~ie.*~~ In young soils total Co can be predicted reasonably accurately from a knowledge of the geological nature of their parent materials. In more mature soils which have Table 19 Cobalt soil contents (mg Co kg-') Soils 44 soils, E. Canada, 8 profiles 100 topsoils, Finland 18 soils, USA, 6 profiles 124 topsoils, Queensland 122 soils, Australia, 20 profiles 36 soils, Scotland, 7 profiles 129 topsoils, S.W. Pacific 23 soils, Israel, 8 profiles 19 soils, USA, 4 profiles 375 topsoils, Finland 15 soils, Wales, 5 profiles 360 soils, China, 111 profiles 108 soils, Ghana, 19 profiles 19 soils, Germany, 4 profiles 195 soils, California, 50 profiles 210 topsoils, Burma 68 soils, Burma, 17 profiles 238 topsoils, USSR 12 soils, world-wide 1 13 soils, Madagascar, 26 profiles 863 topsoils, USA 110 soils, Cameroon, 18 profiles 36 soils, Israel, 10 profiles 5 1 soils, Israel, 12 profiles 27 soils, Japan, 7 profiles 1084 topsoils, European USSR 9 soils, Brazil 295 topsoils, Ontario 46 soils, Poland, 9 profiles 36 1 topsoils, Sweden 43 soils, Bulgaria 4 soils, Canada 5 1 topsoils, Denmark 421 topsoils, England and Wales

Range 0.8-18.2

< 10-60

ND-12 1-120 (2-43 <1-40

Mean 8.9 17.2 3.8 24.6 6.5 18.8

-

18.4

1.7- 10.6 <3--171 7-23 3-30 5-47 < 10-200 20-100 2.O-7 8.5 6-2 1

5.9 37.2 14.1 18.3 23 16.6 60.5 17.1 11.2 13.4 7.4 14.1 17.3 10 1.69 4.7 9.4 60.6 7.34 7.6 4.4 4.05 4.8 19.9 12.0 23 median 8

-

0.4-64.9 3-46 <3-70 6.7-52 < 1-10 <1-26 35-104 -

0.5- 17 1.O- 16.7 0.8-24.0 0.3-17 3.0-64.8 4.9-28 -

< 1-40

R eJ: a 3 82 228 19 b 3 4 C

92 d 5

e 6 8

f 21

505 165 22 77 23 g h 16 i

70 j

k

I 504 m n 299*

"'R. M. McKenzie, in 'Trace Elements in Soil-Plant-Animal Systems', ed. D. J . D. Nicholas and A. R. 264

Egan, Academic Press. London, 1975, p. 83. K. G . Tiller, J. L. Honeysett, and E. G. Hallsworth, Ausf.J . Soil Res., 19fi9, 7,43.

133

The Elemental Constituents of Soils

Table 19 (con!.) Soils

Range

Mean

23 soils, Scotland, 4 profiles 2-40 17.3 173 soils, Canada, 53 profiles 5-50 21.0 Overall Mean 12.0 mg Co kg-’ 5504 Soils

Ref. 122 0

* Not included in Mean J. R. Wright, R. Levick, and H. J. Atkinson, Soil Sci. SOC.Am. Proc., 1955, 19, 340; R. M. Mackenzie, C.S.I.R.O. (Australia) Div. Soils Divl. Rep., 6/60, pp. 17; S. Ravikovitch, M. Margolin, and J. Navrot, Soil Sci., 1961, 92, 85; 0. Makitie, Maataloust, Aikak.. 1962, 34, 91; ‘C. L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica, 1963, 11, 130; ’G.R. Bradford, R. J. Arkley, P. F. Pratt, and F. L. Blair, Hilgardia, 1967, 38, 541; S. Ravikovitch and J. Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, pp. 20; J. Navrot and S. Ravikovitch, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, pp. 20; Yu. N. Zborishchuk and N. G . Zyrin, Sou. Soil Sci., 1974, 6, 209; j R. Frank, K. Ishida, and P. Suda, Can. J. Soil Sci., 1976, 56, 181; A. Sapek and P. Sklodowski, Rocz. Glebozn., 1976, 27, 137; ‘A. Anderson, Swedish J. Agric. Res., 1977, 7, 7; R. D. Koons and P. A. Helmke, Soil Sci. SOC.Am. J., 1978, 42, 237; * J. C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28, 81; O J. A. McKeague and M. S. Wolynetz, Geoderma, 1980, 24,299

undergone several cycles of weathering, such as those in parts of Australia, much of the total cobalt in the soil may be associated with manganese oxide minerals.250 During pedological weathering cobalt released from primary minerals can 267 and manganese Cobalt accumulate on clay minerals,265iron oxides,266* does not appear to be strongly associated with organic matter in soils and, where secondary manganese oxides are a significant phase, these appear to be the most active in adsorbing Cobalt is adsorbed much more strongly on to manganese than on to iron oxides and the adsorption appears to be specific since, unlike Cu and Ni, the adsorbed Co is not easily r e l e a ~ e d . ~ ~ * * ~ ~ ~ Interest in the presence of cobalt in soils developed after 1935 when it was discovered that an adequate supply of cobalt in pastures is essential to the health of grazing animals. The manner in which soil factors such as drainage,’22pH,2*270 and manganese contentz7’affect the mobilization and plant uptake of cobalt have been described. While the chief interest in soil cobalt lies in its importance for ruminant animals, in which it is essential for the production of vitamin BI2,there is also evidence that it plays some part in plant nutrition and this aspect has been reviewed by C ~ m h a i r eThe . ~ ~biology ~ and biochemistry of cobalt has been reviewed recently by Young.273

Nickel.-Geochemistry. There are no common rock-forming minerals of nickel but some Ni-rich sulphides occur in basic and ultrabasic rocks as accessories. Olivine is the major host mineral for Ni in ultrabasic rocks and often contains 3000 mg Ni K. G. Tiller, J. F. Hodgson, and M. Peech, Soil Sci., 1963,95, 392. H. Grimme, Z . Pflanzenernaehr. Bodenkde., 1968, 121,58. 267 H. H. Le Riche, Geoderma, 1973,9,43. 26R R. M. McKenzie, Aust. J . Soil Res., 1967, 5 , 235. 269 R. M. McKenzie, Aust. J . Soil Res., 1970, 8, 97. 270 J. W. S. Reith and R. L. Mitchell, Plant Anal. Fert. Probl., 1964, 4, 24 1. 2 7 1 S. N. Adams, J. L. Honeysett, K. G. Tiller, and K. Norrish, Aust. J . Soil. Res., 1969, 7, 29. 272 M. Comhaire, Agric. Digest., 1968, No. 14, 9. 2 7 3 R. S. Young, ‘Cobalt in Biology and Biochemistry’, Academic Press, London, 1979, 144 pp. 265 266

Environmental Chemistry

134

kg--l. Nickel also enters other ferromagnesian minerals such as pyroxenes, amphiboles, and serpentine in lesser amounts and contents in igneous rocks generally fall in the order ultrabasic > basalts > andesites > granites and rhyolites. Contents of Ni in rocks are often correlated with those of Mg, Co, or Cr.274The crustal average for Ni has been reported to be 75 mg kg -'with averages for basalt of 150 mg kg-' and for granite of 0.5 mg kg-'.75

Weathering and Mobility. Nickel is relatively easily mobilized during weathering because it is contained in the more easily weathered ferromagnesian minerals. It is, however, coprecipitated with iron and manganese oxides. In tropical climates, where ultrabasic rocks rich in Ni are weathered, a residual Ni-rich lateritic soil develops which is of economic importance. The common Ni-mineral associated with these deposits is garnierite which is now the source of about half the total annual Ni production. Nickel, together with other metals, is also concentrated in marine manganese nodules.274 Soil Contents. The total nickel contents of 4625 samples of soil detailed in Table 20 range from 0.1-1523 mg kg-' with a mean of 33.7 mg kg-'. Soil nickel Table 20 Nickel soil contents (mg Ni kg-') Soils 100 topsoils, Finland 18 soils, USA, 6 profiles 36 soils, Scotland, 7 profiles 129 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 375 topsoils, Finland 360 soils, China, 11 1 profiles 108 soils, Ghana, 19 profiles 68 soils, Spain, 23 profiles 19 soils, Germany, 4 profiles 195 soils, California, USA, 50 profiles 34 soils, Galapagos, 13 profiles 34 soils, Poland, 9 profiles 210 topsoils, Burma 68 soils. Burma, 17 profiles 113 soils, Madagascar, 26 profiles 64 soils, Poland, 22 profiles 863 topsoils, USA 110 soils, Cameroon, 18 profiles 27 soils, Japan, 7 profiles 39 topsoils, Canada 293 topsoils, Ontario 46 soils, Poland, 9 profiles 36 1 topsoils, Sweden 260 topsoils, Wales 230 subsoils, Wales 66 soils, USSR, 18 profiles 5 1 topsoils, Denmark 752 topsoils, England and Wales 274

Range

< 10-300 2-77 4- I50 -

5-27 13-46 11-180 < 10-200 3.2-957 20-300 4.2- 1 5 23 20-270 16-35 -

12-93 3-530 12-92 <5-700 12-380 24-322 13-145 1.3-1 19 4.4-3 1 0.1-64 9- 142 8-70 10-70 -

4.4-228

Mean 86 26 53 43 13 24 51 32 52 111 81 120 26 31 42 74 39 20 63 105 43 16 13 8.7 29 33 31 7.4 (median 26)

K. H . Wedepohl, 'Handbook of Geochemistry', 11-3/28, Springer-Verlag, Berlin.

R eJ:

382 228 3

4 92 a b 6 c

8 d 9 e 21 21 22

f

77 23 16 475 g

h I

j

.i k

1

299*

135

The Elemental Constituents of Soils Table 20 (cont.) Soils

Range

Mean

ReJ

20

122

23 soils, Scotland, 4 profiles 6-60 12 1 topsoils, Wales 12 topsoils, S.E. USA 8-247 173 soils, Canada, 53 profiles 5-50 4625 Soils Overall Mean 33.7 mg Ni kg

20

m

55

805 n

20

* Not included in Mean “ 0 .Makitie, Maaraloust. Aikak., 1962, 34. 91: ’C. L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica. 1963, 11, 130; T. C. Fernandez, M. M. Taboadela, and F . G. Ojea, An. Edafol. Agrobiol., 1965, 24,267: G. R. Bradford. R. J . Arkley, P. F. Pratt, and F. L. Blair, Hilgardia. 1967, 38. 541; “J. Glinski, J. Melke, and S. Uziak. Rocr. Glebozn., 1968, 19, 73: f B . Dobrianski and J. Glinski, ibid., 1971, 21, 365: x R . Frank, K. Ishida, and P. Suda, Can. J . Soil. Sci.,1976, 56, 181: A. Sapek and P. Sklodowski, Rocz. Glebozn., 1976. 27. 137; Andersson. Swedish J . Agric. Res., 1977, 7, 7:’ R. 1. Bradley, C. C. Rudeforth, and C. Wilkins, J. Soil Sci..1978, 29, 258; B. K. Shakuri, sou. soil Sci., 1978, (lo), 189; ‘ J . C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28, 81; R. 1. Bradley, Geoderma, 1980, 24, 17; J . A. McKeague and M . S. Wolynetz, ibid., p . 299 [

concentration ranges of 5-500 mg kg-’ y3 and 2-750 mg kg-I 74 and mean and ~,’~ median contents of 40 and 5 0 mg kg-I, respectively, have been r e p ~ r t e d . ~Soil contents are generally related to those of their parent rocks. Other factors also affect the nickel content of soils including soil type, degree of development, content of clay, and secondary sesquioxides and organic matter content. During pedological weathering nickel is released from primary minerals and this process is intensified under poor drainage conditions. I n a soil developed on basic igneous parent material about 50% of the total nickel was mobilized.’22 There is little evidence that nickel is removed by leaching from soil profiles and, in temperate climates, mobilized nickel tends to accumulate in clays as shown by Shorty2and Le Riche and Weir,95 and in secondary Fe and Mn oxides. Soils derived from serpentine and basic rocks contain larger amounts of nickel than those derived from granite or sandstone. Numerous analyses for total nickel have been made of soils developed on ultrabasic rocks in many parts of the ~ o r l d . ~ Total ~ ~nickel ~ ~contents ~ ~ in - these ~ ~ soils ~ .are~generally ~ ~ within the range 1000-5000 mg kg-I. The figures in Table 20 have excluded values for serpentine soils as these are a special case. A comprehensive review of the ecology of serpentine soils has been prepared by Proctor and Woodell.240 Nickel contents in soils can be increased by the use of some sewage sludges as fertilizer^,^^' whereas nickel levels in soils one mile from a smelter in South Wales have been increased to 1150 mg kg-’.276 A survey of investigations on the nickel content of Polish soils has been prepared by Boratynski et al.233 Nickel occurs as a trace element in all organisms but an essential function in the metabolism of animals has only recently been establishedg6 Nickel accumulator plants associated with soils developed on ultrabasic rocks are well known277*27R and because nickel is readily taken up into the aerial portions of plants biogeochemical prospecting is a useful technique in the search for ore bodies. D. R. Slingsby and D. H. Brown,./. Ecol., 1977, 65, 597. W. M. Ashton, Nature (London), 1972, 237, 46. 277 R. R. Brooks, J. Lee, and T. Jaffre,J. Ecol., 1974, 62,493. 278T.Jaffre, R. R. Brooks, J. Lee, and R. D. Reeves, Science. 1976. 193. 579. 275

276

En vironmen la I Chemistry

136

9 Copper, Zinc, and Cadmium Copper.-Geochemistry. Chalcopyrite CuFeS, is a common accessory mineral in igneous rocks and particularly in the more basic types. Average copper contents in rock-forming minerals are olivines 1 15, pyroxenes 120, amphiboles 78, biotites 86, plagioclases 62, and magnetites 76 mg kg-I. These averages and the large overlap of concentration ranges indicate that there is no strong tendency for copper to be incorporated into any particular crystal structure. The minerals probably contain intergrowths or inclusions of copper ~ulphides.~’~ Average copper concentrations in different rock types are: ultrabasic rocks 47, basalts and gabbros 40-60, alkalic rocks <20, intermediate rocks 10-20, granitic rocks 12-15, greywackes, etc. 30, argillaceous rocks 20-40, carbonate rocks 6, schists and gneisses 22 mg kg-’.279 Weathering and Mobility. Copper is released from silicates, sulphides, and oxides when rocks decompose on weathering and the released copper is adsorbed by clay minerals, iron and manganese oxides, and organic matter. The generally low concentration of copper in fresh waters indicates its restricted mobility. Mobilization of copper is probably related to the oxidation of chalcopyrite in the Table 21 Copper soil contents (mg Cu kg-’) Soils 44 soils, E. Canada, 8 profiles 13 1 topsoils, Finland 18 soils, USA, 6 profiles 124 topsoils, Queensland, Australia 122 soils, Australia, 20 profiles 4 1 soils, Scotland, 8 profiles 134 topsoils, S.W. Pacific 20 soils, Israel, 7 profiles 19 soils, USA, 4 profiles 15 soils, Wales, 5 profiles 360 soils, China, 1 1 1 profiles 108 soils, Ghana, 19 profiles 82 topsoils, Victoria, Australia 195 soils, California, USA, 50 profiles 34 soils, Galapagos, 13 profiles 34 soils, Poland, 9 profiles 2 10 topsoils, Burma 68 soils, Burma, 17 profiles 325 topsoils, USSR I 13 soils, Madagascar, 26 profiles 29 soils, Papua-New Guinea, 6 profiles 190 soils, Colorado, USA, 37 profiles 20 topsoils, South Africa 64 soils, Poland, 22 profiles 261 soils, New Brunswick, 56 profiles 44 topsoils, Rajasthan, India 863 topsoils, USA 50 soils, Japan, profiles 279

Range 1-23 <30-300 4-98 1-190 3.5- 150 3-50 14-6 1.5 5-203 3-150 4-72 10-I00 2-50 0-1 12 7- 130 1 1.5-36 4-48 5-9 1 27-135 2-92 2.1-30 4.8-89 <5-230 20-229 < 1-300 2-160

Mean 11.2 85.7 28 43.4 19.2 23 .O 49.1 31.3 60.6 44.4 22 26.7 9.9 31.5 50 21 16.6 19.1 15.2 36.7 79.1 16.2 14.7 21.7 14.5 68.4 25 45.0

K. H. Wedepohl, ‘Handbook of’Geochemistry’, 11-3/29, Springer-Verlag. Berlin.

R ef: a 302 228 19 b 3 4 C

92 5

d 6

e

f 9 g

21 505 22 h 12 i j

252 k 77

I

137

The Elemental Constituents of Soils Table 21 (cont.) Soils Range Mean 31.3 1 1.5-68 110 soils, Cameroon, 18 profiles 15.4 2.7-34 30 soils, Israel, 10 profiles 22.9 1.9-57 5 1 soils, Israel, 12 profiles 21.9 1.4-19 1 62 soils, Spain, 22 profiles 2.8-27 7.5 64 soils, Poland, 12 profiles 42.9 12-107 30 soils, Japan, 8 profiles 29.5 3.5-72 25 soils, Egypt, mainly topsoils 13-100 53.4 10 topsoils, Rajasthan, India 20.0 6.0-139 75 topsoils, Salamanca, Spain 20.1 4.4-64 24 topsoils, Britain 19.5 3-8 1 162 topsoils, Nova Scotia 31.8 14-84 35 topsoils, India 21.5 1298 topsoils, European USSR 24.4 8-6 1 39 topsoils, Canada 16-150 48.6 3 7 topsoils, England 54.5 1-389 227 soils, Brazil, 28 profiles (median 14) 3-80 46 topsoils, England 3 1-50 43 20 topsoils, India 25.4 2.1-144 295 topsoils, Ontario 18.8 1-65 13 soils, Britain 20.3 3.G49.0 216 soils, Louisiana, 72 profiles 1.6-29.0 8.8 46 soils, Poland, 9 profiles 14.6 1.5-190 36 1 topsoils, Sweden 34 14-73 261 topsoils, Wales 32 9-76 230 subsoils, Wales 12.5 5 1 topsoils, Denmark 22.9 1.8-70 1300 topsoils, European USSR 1.8-195 (median 17) 75 1 topsoils, England and Wales 11.5 23 soils, Scotland, 4 profiles < 5-40 11.0 12 1 topsoils, Wales 26.2 5-74 12 topsoils, S.E. USA 22.0 5-50 173 soils, Canada, 53 profiles Overall Mean 25.8 mg Cu kg-' 78 19 Soils

R eJ:

23 m n 0

P 16 9

r S

28 1 t U 11

475 193 301 298* W X

292 289 V

z aa aa bb 300 299* 122 cc

805 dd

* Not included in Mean J. R. Wright, R. Levick. and H. J. Atkinson, Soil Sci. SOC.Am. Proc., 1955. 19, 340; R. M. McKenzie, C.S.I.R.O. (Australia) Div. Soils Div. Report, 1960, 6/60. 17 pp: S. Ravikovitch, M. Margolin, and J. Navrot, Soil Sci., 1961, 92, 85; C. L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica, 1963, 11, 130; R. M. McKenzie, Aust. J . Exp. Agric. Anim. Husb., 1966, 6, 170: fG.R. Bradford, R. J. Arkley, P. F. Pratt, and F. L. Blair, Hilgardia, 1967, 38, 541; g J. Glinski, J. Melke, and S. Uziak, Rocz. Glebozn., 1968, 19, 73: P. Bleeker and M. P. Austin, Aust. J . Soil Res., 1970, 8, 133; 'C.P. de L. Beyers and T. Hammond, Agrochernophysica, 1971, 3, 23: 'B. Dobrazanski and J . Glinski, Rocz. Glebozn., 1971, 21, 365; S. P. Seth, R. K. Bhatnagar. G. P. Nathani, and Q. U. Zaman, Soil Sci. Plant Nutr., 1971, 15, 17: ' J . Masui, S. Shoji. and K. Minami, ibid., 1972, 18, 31: S. Ravikovitch and J. Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp, 13-20; " S. Ravikovitch and J. Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp, 1-12; " E . Barragan Landa and J. I. Herrero, An. Edafol. Agrobiol., 1973, 32, 89: P W . Dzieciolowski and Z. Kocialkowski, Rocz. Glebozn., 1973, 24. 241: 'JF. M. Kishk, M. N. Hassan, I. Ghanem, and L. El-Sissy, Plant Soil, 1973, 39, 487: F. La1 and T. D. Biswas, J. Indian SOC.Soil Sci., 1973, 21, 455; F. D. Macias, Soil Sci., 1973, 115, 276: ' K . S. MacLean and W. M. Langville, Commun. Soil Sci. Plant Anal., 1973, 4, 495; B. M. Sharma and D. L. Deb. J . Indian SOC.Soil Sci., 1974, 22, 145; " Yu. N. Zborishchuk and N. G. Zyrin, Sou. Soil Sci., 1974, (6), 209; K. N . Dwivedi and H. Shanker, Indian J. Agric. Res., 1976, 10, 43: R. Frank, K . Tshida, and P. Suda, Can. J. Soil Sci., 1976, 56, 181; A. Sapek and P. Sklodowski, Rocz. Glebozn., 1976. 27, 137; :A. Andersson, Swedish J . Agric. Res., 1977, 7, 7; u' R. I. Bradley, C. C. Rudeforth, and C. Wilkins, J . Soil Sci., 1978, 29, 258; J. C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28. 81: cc R. I. Bradley, Geoderma. 1980, 24, 17; dd J. A. McKeague and M. S. Wolynetz, ibid., p. 299 (I

138

Environmental Chemistry

more basic rocks and to the weathering of biotite in other rocks. In a study of Iaterization of granite Wedepohl found that a fresh granite in India contained 8 mg Cu kg-I and 26% quartz, whereas the average kaolinized granite contained 6 mg Cu kg-' and 68% quartz. Much of the original copper had been lost and accumulated in horizons with ferruginous concentrations in the kaolinized The degree of weathering and release of copper is probably much less extensive in temperate regions.

Soil Contents. The usual total copper content of soils lies in the range 2 to 100 mg kg-I 93 with most values in the range 25-60 mg kg-1.280 A scheme distinguishing five different Cu-containing fractions in twenty-four British soils has been devised.281The distribution of copper fractions in seven profiles of grey-brown podzolic soils developed on loess has also been studied by Grimme282using a selective extraction procedure. Mobile copper in soils is adsorbed by manganese oxides,268iron ~ x i d e s , ~ ~ ? ~ ~ organic matter,284 and clay minerals.28s More recently McLaren and Crawford286 have shown that organic matter and manganese oxides dominate the specific adsorption of soil copper. Copper absorption on soil constituents follows the order manganese oxides > organic matter > iron oxides > clay minerals. Because copper is rapidly adsorbed by clay minerals and secondary weathering products, fine textured alluvial soils are generally richer in total copper than sandy soils.2R7Changes in total copper content with increase in depth in soil profiles, particularly cultivated profiles, are generally small. Copper sometimes accumulates to some degree in illuvial horizon^.^^^,^^^ Accumulation of copper in upper horizons of p r ~ f i l e iss normally ~ ~ ~ ~ most ~ ~ ~striking in those where there has been extensive A ~portion ' of the development of a surface humus horizon e.g. in peaty p o d ~ o l s . ~ copper in humic acids extracted from cultivated and uncultivated soils and also peats is present as a copper-porphyrin complex. 292 Copper contents in soils can be greatly increased (by several hundred mg kg-I) by the regular use of copper fungicides on crops such as vines293and and by the disposal of distillery waste,295and sewage sludge.241The disposal of pig slurry D. D. Hemphill, Ann. N . Y . Acad. Sci., 1972, 199,46. R. G . McLaren and D. V. Crawford, J . Soil Sci.,1973,24, 172. la2H. Grimme, Z . Pflanrenernaehr. Dueng. Bodenkde., 1976. 116, 125. 2R3 E. A. Forbes, A. M. Posner, and J. P. Quirk, J . Soil Sci., 1976, 27, 154. 2R4 F. J . Stevenson and M. S. Ardakani, in 'Micronutrients in Agriculture' ed. J . J . Mortvedt, P. M. Giordano, and W. L. Lindsay, Soil Sci. SOC.Am. Inc., Madison, Wisc., USA, 1972, p. 79. 28s A. Heydemann, Geochim. Cosmochim. Acta, 1959, 15,305. 28h R. G. McLaren and D. V. Crawford, J . Soil Sci., 1973, 24,443. "' F. M. Kishk, M. N. Hassan, 1. Ghanem, and L. El-Sissy, Plant Soil,1973, 39.487. *" A. A. Daerbaev, Pochuoaedenie, 1973, No. 12. IS. 289 H. Karim, J. E. Sedberry, and B. J. Miller, Commun. Soil Sci. Plant Anal., 1976, 7,437. 290 M. S. Panin, Agrokhimiya, 1972, No. 2, 126. 2 y I M . V . Cheshire, M. L. Berrow, B. A. Goodman, and C. M. Mundie, Proc. Int. Colloq. C N R S in 'Migrations organo-minerales dans les sols temperes', Nancy 1979, in press, 198 1. 2 y 2 B. A. Goodman and M. V . Cheshire, Soil Sci., 1976, 27, 337. 293 J. Delas, Agrochimica., 1963, 7, 258. 294 F. Hoed, A. Speleers. G. Dardenne, and P. H. Martens, Meded. Lartdh. Hogesch. Gent., 1961, 26,

28u "I

2y5

1484. J. W. S . Reith, M. L. Berrow, and J. C. Burridge, Proc. Int. Conf. Heavy Metals in the Environment, London. C.E.P. Consultants Ltd., Edinburgh, 1979, p. 537.

The Elemental Constituents of Soils

139

from animals receiving copper supplements can also lead to a slow build up of copper in the It has been estimated that the addition of 250 mg Cu kg-' as copper sulphate to pig rations could supply 1.5-3.0 mg kg-' to the surface soil annually where the manure is applied as a source of nitrogen to maize.297 The average total copper content in 7819 uncontaminated soil samples from various parts of the world is 25.8 mg kg-I, Table 21. This compares with median contents of 14298and 17299mg kg-' in 46 and 751 topsoils, respectively, from various parts of Britain. The overall mean content in Table 21 is close to the median n ~ to ~ the mean contents of the topsoils contents of 30 mg kg-' quoted by B ~ w e and of 28 different Russian soil types, comprising some 1300 topsoils, of 22.9 mg kg-'.300 Early estimates by Vinogradov6' gave a mean of 20 mg kg-I. A review of work carried out on copper in Polish soils has been published by Boratynski et al.256 Copper is essential to the growth of plants but can also cause toxicity problems when soil levels are high. Copper deficiency symptoms in plants occur most often in peat and muck soils, sandy soils,3o2calcareous sands, leached acid sands and soils heavily fertilized with nitrogen.303Plants growing in high copper environments often translocate surprisingly little copper to their leaves but generally accumulate large amounts of copper in their roots.304 Copper is also essential to the growth of animals but can be toxic, particularly to

Zinc.-Geochemistry. Zinc substitutes for ferrous iron and magnesium (or other ions with about 0.8 A radius) in silicate and oxide minerals but can also occur as the mineral sphalerite, ZnS, in some rocks. Magnetite is probably the most important zinc-carrier in basaltic gabbroic rocks and biotite in granitic rocks. Where the two minerals coexist in the same rock biotite usually contains more zinc. Average zinc concentrations in different rock types are: ultrabasic rocks 56, basalts and gabbros 100, alkalic rocks 70, intermediate rocks 70, granitic rocks 50, greywackes 100, argillaceous rocks 120, bituminous clays 200, limestones 20, quartz sandstones and arkoses 30, and schists and gneisses 65 rng Zn kg-'. The abundance of zinc in the earth's crust has been computed as 60305 and 70 rng kg-'.75 Weathering and Mobility. Zinc, occurring primarily in the structure of silicates and oxides, goes into solution during the chemical weathering of these minerals. Sulphide weathering gives rise to relatively high concentrations of dissolved zinc because of the solubility of zinc ~ u l p h a t eThe . ~ ~released ~ zinc is generally absorbed R. J . Unwin, in 'Inorganic Pollution and Agriculture', M A F F Reference Book 326, HMSO, London. 1980, p. 306. 2q7 D. E. Baker, Fed. Proc.. 1974, 33, 1 188. 298 B. J . Alloway, J . Agric. Sci., Camb.. 1976, 86, 93. 299 F. C. Archer, in 'Inorganic Pollution and Agriculture', M A F F Ref. Book 326, HMSO, London, 1980. p. 184. 'On Yu. N. Zborishchuk and N . G. Zyrin, Sou. Soil Sci., 1978. (10). 27. 3n1 J. M. A. S. Valadares, Braganria., 1975, 34. 125. 3"2 D. Purves and J. M. Ragg. J . Soil Sci., 1962, 13, 24 1. '03 W. Reuther and C . K. Labanauskas, in 'Diagnostic Criteria for Plants and Soils', ed. H. D. Chapman, Univ. of California, Div. of Agric. Sci., Riverside, California, 1966, p. 157. '04 S. G. Jarvis and L. H. P. Jones, J . Sci. Food Agric.. 1979. 30. 742. 305 K . H. Wedepohl (ed.), 'Handbook of Geochemistry', I1 3/30. Springer-Verlag, Berlin. 306 H. F. Massey and R. 1. Barnhisel, Soil Sci., 1972. 113, 207. 2yb

Environmental Chemistry

140

by clays and secondary oxides unless the solution is unusually acid, and the low concentration of zinc (10 pug I-') in natural surface waters indicates restricted mobility.

Soil Contents. The total Zn contents of 7402 soils listed in Table 22 range from 1.5-2000 mg kg-', with an overall mean of 59.8 mg kg-'. This compares with the Table 22 Zinc soil contents (mg Zn kg-') Soils 44 soils, E. Canada, 8 profiles 18 soils, USA, 6 profiles 124 topsoils, Queensland, Australia I2 1 soils, Australia, 20 profiles 20 soils, Israel, 7 profiles 360 soils, China, I 1 1 profiles 139 soils, Quebec, B horizons 82 topsoils, Victoria, Australia I95 soils, California, USA, 50 profiles 34 soils, Galapagos, 13 profiles 28 1 topsoils, USSR 29 soils, Papua-New Guinea, 6 profiles 27 soils, Nebraska, USA, 4 profiles 191 soils, Colorado, USA, 37 profiles 26 1 soils, New Brunswick, 56 profiles 44 topsoils, Rajasthan, India 863 topsoils, USA 120 topsoils, Indore, India 86 topsoils, British Columbia 50 soils, Japan, profiles 5 1 soils, Israel, 12 profiles 36 soils, Israel, 10 profiles 69 topsoils, Nova Scotia 690 soils, Poland, 173 profiles 29 soils, Portugal, 6 profiles 35 topsoils, Delhi, India 64 soils, Poland, 12 profiles 286 topsoils, Madhya Pradesh, India 10 topsoils, Rajasthan, India 75 topsoils, Salamanca, Spain 28 topsoils, Western Nigeria 36 soils, Nainital Tarai, India 25 1 soils, New Zealand, 33 profiles 54 1 topsoils, European USSR 9 topsoils, Brazil 39 topsoils, Manitoba and Winnipeg 37 topsoils, England 46 topsoils, England 20 topsoils, Bundelkhand, India 296 topsoils, Ontario 2 16 soils, Louisiana, USA 98 soils, Spain, 2 1 profiles 46 soils, Poland, 9 profiles 36 1 topsoils, Sweden 260 topsoils, Wales

Range 10-150 14-3 20 5-180 11-86 48-214 12-250 -

1.5-100 28-2 12 22- 170 -

27-92 43- 120 8- 148 10-330 5 .O-9 5 (25-2000 40-13 1 -

Mean 62 148 62 40 107 85 189 16 81 65 45 53 70 58 80 37 54 71 105 108 75 53

55-205 16-169 14-92 14-108 54 3.5-90 28 (5-93 42 28-1 26 61 2-175 47 6.9-131 34 3 3-90 59 7.0-125 45 7.5-39 19 79 49-1 1 1 14-200 56 40 72 5-131 109 56-350 42-284 117 23-184 (median 67) 53-65 59 4.6- 162 54 7-1 50 42 28-420 144 32-235 79 4.0-3 10 59 14-229 70

R ef a 228 19 b c

d 7

e

f

9 505 g

321 12 252 h 77 i j

k 1

m n 0

P 9

r S

t U

315 V

308 W

7 475 193 298* X

v 3 12 z aa bb cc

14 1

The Elemental Constituents of Soils Table 22 (cont.) Soils

Range

230 subsoils, Wales 10-183 43 soils, Manitoba, 8 profiles 7.5-137 4 soils, Canada 56-164 5 1 topsoils, Denmark 600 topsoils, USSR 3.5-139 26 topsoils, Egypt 39-99 47 soils, Nigeria, 1 1 profiles 9-84 748 topsoils, England and Wales 5-816 23 soils, Scotland, 4 profiles 20- I00 12 1 topsoils, Wales 12 topsoils, S.E. USA 15-103 173 soils, Canada, 5 3 profiles 10-200 7402 Soils Mean Content 59.8 mg Zn kg-'

Mean 62 56 110 31 50?' 76 42 (median 77) 60 73 70 74

Ref: CC

dd ee

ff

300* gg

3 10 299* 122 hh 805 ii

* Not included in Mean t Mean of Means J. R. Wright, R. Levick, and H. J. Atkinson, Soil Sci. SOC.Am. Proc., 1955, 19, 340: R. M. McKenzie, C.S.I.R.O. (Australia) Div. Soils, Div. Rep, 1960, 6/60, 17 pp: S. Ravikovitch, M. Margolin, and J. Navrot, Soil Sci., 1961, 92, 85; d C . L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica, 1963, 11, 130; R. M. McKenzie, Aust. J. Exp. Agric. Anim. Husb., 1966, 6, 170; 'G. R. Bradford, R. J . Arkley, P. F. Pratt, and F. L. Blair, Hilgardia, 1967, 38, 541; P. Bleeker and M. P. Austin, Aust. J . Soil Res., 1970, 8, 133; h S . P. Seth, R. K. Bhatnagar, G. P. Nathani, and Q. U. Zamau, Soil Sci. Plant Nutr., 1971, 17, IS; I G. P. Gupta and D. Singh, J . Indian SOC.Soil Sci., 1972, 20, 49; j M. K. John, Soil Sci., 1972, 113, 222; J. Masui, S. Shoji, and K. Manami, Soil Sci. Plant. Nutr., 1972, 18, 31; 'S. Ravikovitch and J. Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp., 1-12; J. Navrot and S. Ravikovitch, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp., 13-20; R. F. Bishop and C. R. Maceachern, Commun. Soil Sci. Plant Anal., 1973, 4, 41; " Z. Chudecki, H . Grienert, E. Neidzwiecki, and Z. Zablocki, Pol. J. Soil Sci., 1973, 6, 37; A. S. Coutinho, A. J. S . Teixeira, E. M. Sequeira, and M. D. Lucas, Agron. Luist.. 1973, 33. 257; D. L. Deb and B. M. Sharma, fndian J . Agric. Sci., 1973, 43, 424; W. Dzieciolowski 'and Z. Kocialkowski, Rocz. Clebozn., 1973, 24, 241; ' B. L. Ganjir, S. B. Sinha, and B. S. Bhargava, J. Indian SOC.Soil Sci.. 1973, 21, 441; * F. La1 and T. D. Biswas, ibid., p. 455; D. F. Macias, Soil Sci., 1973, 115, 276; " K. P. R. Vittal and M. S . Gangwar, J. Indian SOC.Soil Sci., 1974, 22, 151; "Yu. N. Zborishchuk and N. G. Zyrin, Sou. Soil Sci., 1974, (61, 209; K. N. Dwivedi and H. Shanker, fndian J.Agric. Res., 1976, 10,43; R. Frank, K. Ishida, and P. Suda, Can. J . Soil Sci., 1976, 56, 181; G. F. Ojea and A. M. L. Couce, A n . Edafol. Agrobiol., 1976, 35, 1191; ua A. Sapek and P. Sklodowski, Rocz. Glebozn., 1976, 27, 137; bb A. Andersson, Swedish J . Agric. Res., 1977, 7, 7; cC R. I. Bradley, C. C. Rudeforth, and C. Wilkins, J . Soil Sci., 1978, 29, 258; dd M. Kalbasi and G. J. Racz, Can. J . Soil Sci., 1978, 58, 61; re R. D. Koons and P. A. Helmke,SoilSci.Soc.Am. J., 1978,42,237;ffJ. C.Tjelland M. F. Hovmand, Acta Agric. Scand., 1978, 28, 8 I ; gg I. H. Elsokkary, Plant Soil. 1979. 53, 117; hh R. I. Bradley, Geoderma, 1980, 24, 17; ' I J. A. McKeague and M. S. Wolynetz, ibid., p. 299 a

mean of the average contents of the topsoils of 25 different Russian soil types comprising some 600 samples of 50.3 mg Zn kg-'.300 A world-wide average Zn content, based on 2000 analyses, is quoted as 50 mg kg-"j8 and a compilation by a normal content in the range 1-900 mg kg-' with a median of 90 B ~ w e n reports '~ mg kg-I. The normal soil content had earlier been stated to be between 10-300 mg kg-'.93 A comprehensive review covering different aspects of zinc in soils has been prepared by Lindsay.307Studies of zinc in New Zealand soils,3o8,in Brazilian soils,3o9and in Nigerian soils31ohave confirmed the dependence of total zinc content W. L. Lindsay, Adu. Agron., 1972, 24, 147. J. S. Whitton and N. Wells, N.Z. J . Sci., 1974, 17, 35 1. 309 J . M. A. S. Valadares and R. A. Catani, Bragantia, 1975, 34, 133. 'lo E. J . Udo and A. A. Fagbami, Commun. Soil Sci. Plant Anal., 1979, 10, 1141. 3v7

142

E t t c'iro n men t a 1 Chem istry

of soils on the geological nature of the parent materials as discussed by Krauskopf."' A survey of investigations on zinc in Polish soils has been prepared by Boratynski et A pedochemical survey of zinc in New Zealand has been carried out by Whitton and and the ranges and mean values of the zinc contents of New Zealand rocks, soils, plants, waters, effluents, and fertilizers reported. They found that acid peats, podzols, and gley podzols had low zinc contents because of losses through leaching. There was no regular pattern, however, of vertical distribution of total zinc in soil profiles. There was a tendency for zinc to accumulate in some surface soils particularly those rich in clay or organic matter. In some soil profiles there is a tendency for zinc to be highest in the subsurface horizon,312while in others there is little change in total content with increase in depth.26j,3 10.3 13 Important factors, other than parent materials, which control the amount of zinc in soils are clay content, iron oxides, organic matter, and pH. Total zinc in soils is often strongly correlated with clay,310*312~314-3'6 iron,305*310,315 3 1 7 and organic matter contents.31xThe fixation of zinc in some calcareous soils has been studied by Navrot el and the relationships between soil pH, availability, and plant The accumulation of zinc in the clay fractions uptake of zinc by Tiller et separated from soils has been reported by Short,92 Dankert and Drew,32' Meelu and Randhawa (see ref. 806) and others. Studies have been made of mechanisms of zinc adsorption on ~ l a y s ,on~ iron ~ ~ , ~ ~ ~ oxides,266v2R' on iron and aluminium oxides,32sand by organic matter.284The soil chemistry of zinc has been studied in detail in twenty-five Australian surface soils representing nine major soil groups.320*326 The total zinc content of these soils ranged from 4-1 83 mg kg-I, with a mean of 46.0 mg kg-I. Zinc is essential to the growth of plants and can also be toxic when present in excess in soilsg8It functions as a specific activator of certain enzymes including of zinc usually arise on soils of peptidases and carbonic a n h y d r a ~ e . ~Deficiencies ~' '*~~~ high pH or following heavy nitrogen or phosphorus f e r t i l i ~ a t i o n . ~ ~ ~A* "review of zinc deficiency problems in the United States dealing with sources and availability of soil zinc, crop requirements, and soil tests has been compiled by K. B. Krauskopf, in 'Micronutrients in Agriculture', ed. J . J. Mortvedt. P. M. Giordano, and W. L. Lindsay, Proc. Syrnp. Soil Sci. SOC.Am.. Madison. Wisc., USA. 1972, p. 7. 3 1 2 H. Karim and J. E. Sedberry, jun., Cotnmun. Soil Sci.Plant Atiul.. 1976. 7.453. J 1 l A. Bauer, Soil Sci. I'lutit Anal.. 1971. 2, 161. J ' 4 M. Kurki, J . Sri. Agric. Soc., k'inland. 1974, 46, 208. ' I J 0 . A. Osiname. E. E. Schulte. and R. B. Corey, J . Sci. Food Agric.. 1973, 24. 134 I . ' I h M. Kalbasi and G. J. Racz. Cun. J . Soil Sci.. 1978. 58. 6 1. ' I 7 R. D. Koons. P. A. Helmke, and M. L. Jackson,./. Soil Sci.. Soc. Am., 1980, 44, 155. A. M. L. Couce and C. F. Ojea. A n . EdaJbl. Agrobiol.. 1976, 35. 1205. J. Navrot. B. Jacoby. and S. Ravikovitch. Pltnc Soil, 1967. 27. 14 I . K . G. Tiller. J . L. Honeysett. and M. P. C . De Vries. A u s t . J . Soil Rcs., 1972. 10, 165. 3 2 1 W. N. Dankert and J . V. Drew. Soil Sci. Soc. A m . Proc., 1970, 34, 916. K. Wada and Y. Kakuto. Cluj~sC l u Mincrals. ~~ 1980, 28, 321. 3 2 3 K. Wada and A. Abd-Elfattah. J . Soil Sci., 1979, 30. 28 I . m S. M. Bromfield. Planl Soil. 1978. 49, 23. '15 D. A. Stanton and R. du T. Burger, Agrochemophjaica, 1970. 2. 65. K. G. Tiller. J. L. Honeysett, and M. P. C. de Vries. Ausf. J . Soil Res.. 1972. 10. 15 1. 327 F. T. Binghani. Soil Sci.. 1959. 88, 7. 32R V. P. Badanur and B. V . Venkata Rao. Soil Sci.. 1974. 116. 292. 311

"" '*' '*"

The Elemental Constituents oJSoils

143

B a ~ e r . Problems ~’~ of zinc toxicity have occurred in the vicinity of mine dumps and zinc smelters and also as a result of the use, as fertilizers, of sewage sludges or town composts which may contain large amounts of zinc in a mobile form.25*329 Zinc is also essential t o the healthy growth of animals.v6 Cadmium.-Geochemistry. In all known compounds of cadmium its valency is two and it is closely related to zinc in rocks and minerals. It occurs in large amounts in zinc minerals such as sphalerite, ZnS, which usually contains 1000 to 5000 mg Cd kg-I. The concentration of cadmium in zinc ores is usually directly related to their zinc content. The average cadmium content of granitic rocks is between 0.1 and 0.2 mg kg-I, whereas shales contain an average of 0.8 mg kg-’ and limestones 0.035 mg kg-l. High contents of cadmium (5.1 and 8.4 mg kg-I) have been observed in manganese nodules.330 The abundance of cadmium in common rock types has been listed by average of 0.2 mg kg-’ has been reported by Page and B i ~ ~ g h a m A . ~ crustal ~’ T a y l ~ r , ’ ~whereas , Heinrichs et ul.332have estimated the average abundance of cadmium in the continental crust as 0.098 mg kg-I. The geochemistry of cadmium in some sedimentary rocks has been reported by Gong, Rose, and S ~ h r . ~ ~ ~ Weathering and Mobility. During weathering cadmium goes into solution and the most important factors which control the cadmium ion concentration in natural waters are pH and oxidation potential. Cadmium can react with goethite at pH values below its isoelectric point,283so iron oxides may act as adsorbing agents for cadmium in soils. The average cadmium content of 37 surface waters from the Irish Sea and English Channel was 0.1 1 b g I-’, ranging from 0.024-0.25 pg I-’, while the average content of 72 Californian spring waters was 8 pg

Soil Contents. The mean total cadmium content of 1642 soils sampled from largely uncontaminated areas in different parts of the world is 0.62 mg kg-’ (Table 23). A range of from 0.001-0.7 mg kg-I, with a mean of 0.1 mg kg-’, has been reported for the cadmium contents of soils of the Russian Plain by Vinogradov,68 who concluded that the character of the parent rock was the main factor determining the cadmium content in soils. A range of 0.01-2 mg Cd kg--’ with a median content of 0.35 mg kg-’ has been reported by B ~ w e n . ’From ~ the available data on cadmium in rocks, Page and B i r ~ g h a m ~and ~ ’ have suggested that soils derived from igneous rocks should contain about 0.1-0.3 mg kg-’, those from metamorphic rocks 0.1-1.0 mg kg-I, and those from sedimentary rocks 0.3-1 I mg kg.’. Uptake d cadmium by plants from the soil is controlled by many factors

729

D. Purves, in ‘Trace Element Contamination of the Environment’. Elsevier. Amsterdam, 1977, 260

PP. K. H . Wedepohl (ed.), ‘Handbook of Geochemistry’, 11 4/48. Springer-Verlag. Berlin.

’” A. L. Page and F. T. Bingham. Residue Reti.. 1973,48, I .

”*

H. Heinrichs. B. Schultz Dobrick, and K . H. Wedepohl. Geochim. Cosr~iochit~~. Acla, 1980. 44, 15 19. H. Gong. A. W. Rose. and N . H. Suhr. Geochirn. Costnorhim. Acta. 1977. 41. 1687.

Environmental Chemistry

144

Table 23 Cadmium soil contents (mg Cd kg-') Soils

Range

Mean

0.12- 1.82 0.56 36 soils, USA, 12 profiles 0.88
ReJ

573 360 476 338 a 475 193 445 445 b C

d

e

f 69 299* 122 k! 343 h h

* Not included in Mean

"R. E. Jervis, B. Fiefenbach, and A. Chatopadhyay. Can. J . Chem., 1974, 52, 3008; * R. Frank, K. Ishida, and P. Suda, Can. J . Soil Sci., 1976, 56, 181; C . H. Williams and D. J. David, Soil Sci., 1976, 121, 86; A. Andersson, Swedish J. Agric. Res., 1977, 7, 7; E. Steinnes, Talanta, 1977, 24, 121; /J. C . Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28, 81; g R. I. Bradley, Geoderma, 1980, 24, 17; M. L. Berrow (unpublished results)

including the plant i t ~ e l f , but ~ ~ soil ~ - pH ~ ~is~a particularly important f a c t o ~ . ~ ~ ' - ~ ~ ' The solubility of both cadmium and lead were found to decrease in soils as pH increased.342The sorption of cadmium by ten agricultural topsoils from Engiand and Wales has been measured and it was found that cadmium was strongly sorbed by soils of pH above 6.0, adding emphasis to the importance of liming as a means of reducing the mobility of cadmium in soils.343 Clay content and cation-exchange capacity of soil also influence plant uptake of cadmium.340Studies have been made of the sorption of cadmium by clays 344 and

F. Haghiri, J . Environ. Quai., 1973, 2, 93. M. K . John, Environ. Pollut., 1973, 4, 7. 336 C. H. Williams, J . Ausl. Inst. Agric. Sci., 1977, 43, 99. 3 3 7 M. K. John, Sci. Total Environ., 1972, 1, 303. 3 3 8 C. H. Williams and D. J. David, Aust. J . Soil Res., 1973, 11,43. 3 3 9 A. Andersson and K. 0. Nilsson, Ambio, 1974, 3, 198. 340 J. E. Miller, J. J. Hassett, and D. E. Koeppe, 9.Environ. Quai., 1976, 5, 157. '' W. R. Chaney, R. C. Strickland. and R. J. Lamoreaux, Plant Soil., 1977,41, 275. 342 J. Santillan-Medrano and J. J. Jurinak, Soil Sci. SOC.Am. Proc., 1975, 39, 851. 343 S. C. Jarvis and L. H. P. Jones, J . Soil Sci., 1980, 31,469. 344 J. Garcia-Miragaya and A. L. Page, J . Soil Sci. Soc. Am., 1972,41, 718. 334 335

145

The Elemental Constituents of Soils

by different soils.345- 3 4 H The influence of soil organic matter content on plant uptake has been studied349*350 and the influence of organic matter on the uptake of heavy metals generally has been reviewed by Kirkham.351High cadmium contents in soils, whether natural or arising from contamination, are often associated with high zinc and the Zn concentration can also influence the uptake of cadmium by plants. The influence of zinc on cadmium uptake has been considered by several workers.349~352,353 A table of cadmium contents in soils, many contaminated by smelter and other activities, has been compiled by Fleischer et al.,354in which cadmium contents of up to 450 mg kg-’ are reported. Cadmium is not essential to the growth of plants or animals but is highly toxic to both. Its long-term persistence in soils, rapid uptake by plants, and the accumulation of injurious concentrations by plants and animals gives some cause for concern over cadmium levels in soils. Many recent reviews and papers33’,354-358 have focused attention on the extent of environmental pollution by cadmium. Sources of cadmium have been reviewed by L i ~ and k ~ by ~ Page and Bingham.”’ Because of its toxicity to plants and animals considerable attention has been paid to the course of transfer of cadmium through agricultural ecosystems from sources such as the dispersal of mine spoil,359 ~ m e I t i n g , ~ ~sewage O - ~ ~ ~sludge disposal on land,363-366 and phosphate fertilizers. 367 Cadmium levels in plants have been studied by S h a ~ k l e t t eand ) ~ ~Haghi~-i,”~ and 3369

M. K. John, Can. J . Soil Sci., 1972, 52, 343. J. V. Lagerwerff and D. L. Brower, Soil Sci. SOC.A m . Proc., 1972, 36, 734. 347 R. Levi-Minzi, G. F. Soldatini, and R. Riffaldi, J . Soil Sci., 1976, 27, 10. 34n J. J. Street, W. L. Lindsay, and B. R. Sabey, J . Environ. Qual., 1977,6, 72. 349 F. Haghiri, J . Environ. Qual., 1974, 3, 180. 350 R. C. Strickland, W. R. Chaney, and R. J. Lamoreaux, Plant Soil, 1979, 52, 393. 3 5 ’ M. B. Kirkham. Compost Sci., 1977, 18. 18. 3sz H. Mizuno and Y. Yamagami, Soil Sci. Plant Nutr., 1972, 20, 204. 3 5 3 K. G. Tiller, V. K. Nayyar, and P. M. Clayton, Aust. J . SoilRes., 1979, 17, 17. 3s4 M. Fleischer, A. F. Sarofin, D. W. Fassett, P. Hammond, H. T. Shacklette, 1. C. T. Nisbet, and S. Epstein, in ‘Environmental Impact of Cadmium’, Environmental Health Perspectives Exp. Issue No. 7, 1974, p. 253. 355 J. V. Lagerwerff, in ‘Micronutrients in Agriculture’ ed. J. J. Mortvedt. J. M. Giordano, and W. L. Lindsay, Soil Sci. SOC.,Am., Madison, Wisc., USA, 1979, p. 593. 356 W. Fulkerson and H. E. Goeller (ed.), ‘Cadmium the Dissipated Element’, Oak Ridge National Laboratory, ORNL NSF-EP-2 1, Oak Ridge, Tennessee, 1973. 3 5 7 L. Friberg, M. Piscator, G. F. Nordberg, and T. Kjellstrom, ‘Cadmium in the Environment’, 2nd Edn, Chemical Rubber Co., Cleveland, 1974, 248 pp. 3 5 * US Environmental Protection Agency, ‘Health Assessment Document for Cadmium’, EPA600/8-79-003, US Environmental Protection Agency, Research Triangle Park, N.C., 1979, 29 1 pp. 359 B. E. Davies and L. J. Roberts, Sci. Total Environ., 1975.4, 249. 360 M. K. John, H. H. Chuah and C. J. Van Laerhoven, Environ. Sci. Technol., 1972, 6, 5 5 5 . 3 6 ’ P. Little and M. H. Martin, Enuiron. Pollut., 1972, 3, 241. ’62 M. H. Martin, P. J. Coughtrey, S. W. Shales, and P. Little, in ‘Inorganic Pollution and Agriculture’, MAFF Ref. Book 326, HMSO, London, 1980, p. 56. 363 F. T. Bingham, A. L. Page, R. J. Mahler, and T. J. Ganje, J. Enciron. Quai., 1975, 4, 207. 364 F. T. Bingham, A. L. Page, R. J. Mahler, and T. J. Ganje. J . Environ. Qual., 1976. 5, 57. 36s R. L. Chaney, P. T. Hundernann, W. T. Palmer, R. J. Small, M. C . White, and A. M. Decker, in Proc. Nat. Conf. on Composting of Municipal Residues and Sludges, Information Transfer Inc., Hazardous Materials Control Research Institute, US Dept. of Agric., Research Services, 1977, p. 86. ’ 6 6 T. D. Hinesly, R. L. Jones, E. L. Ziegler, and J. J. Tyler, Environ. Sci. Techiiol., 1977, 11, 182. T. Stenstrom and M. Vahter, Ambio, 1974, 3, 9 I . H. T. Shacklette ‘Cadmium in Plants’, U S Geol. Surr. Bull. 1972. No. 13 14-G, US Govt. Printing Office, Washington, 28 pp. 34s

346

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the roots of ryegrass plants have been found to accumulate cadmium and restrict its transport to the A review of microelements as related to plant deficiencies and toxicities, including cadmium levels in plants, has been prepared by Chaney and G i ~ r d a n o . ~The ~ ' effects on animals of diets containing enhanced Cd levels have also been 10 The Noble Metals

Silver.-Geochemistry. Silver occurs in nature in its native state and in alloys with gold etc., but is most commonly found as the sulphide in minerals such as galena and pyrite and in combination with Sb, As, Te, and Se in a variety of minerals. It forms halides and a basic sulphate is also found. Crustal average Ag contents have been reported in early work as 80 ,ug kg-'.374Its abundance in the upper lithosphere is about 0.10 mg kg-' with contents in igneous and sedimentary rocks ranging from 0.05-0.12 mg kg-1.375It occurs as a trace in most silicates and may replace Na in silicates rich in An average content of 0.040 mg Ag kg-' for 80 igneous rocks has been Weathering and MobiZity. Silver salts are more soluble in acid conditions than in less acid or alkaline conditions where precipitation of acidic and basic salts and oxides or hydrated oxides may occur. Acid waters tend therefore to transport higher silver concentrations than neutral or alkaline waters. The solubility of silver increases in the presence of sulphate, nitrate, and bicarbonate and is decreased by phosphate, halide, chromate, or arsenate ions, while the presence of hydrogen sulphide or sulphide ions will precipitate silver. The silver contents of stream waters in the USA, reported by Kharkar et ~ f . , ~average ~ ' 0.30 ,ug Ag 1-', but in metalliferous regions the concentrations can be enhanced by up to 100 times."' The transport of silver from silver deposits is illustrated by the enhanced surface soil contents in the Bathurst/Newcastle area (Canada) where extensive sulphide mineralization occurs.z52 The mobility of silver is strongly influenced by the ratio of Fe2+to Fe3+in solution, the silver being precipitated in the presence of high Fe2+and maintained in solution by high Fe3+. The role of manganese is similar.378In soils silver is relatively immobile at pHs > 4 and is strongly adsorbed by organic materials with consequent enrichment in surface horizons; it is similarly relatively immobile in peats, although some organic acids can mobilize silver. Hydrated iron and manganese oxides and S. C. Jarvis and L. H. P. Jones, Plant Soil, 1978,49, 333. 37UR.L. Chaney and P. M. Giordano, in 'Soils for the Management of Organic Wastes and Waste Waters', Am. SOC,Agron., Madison, Wisc., USA, 1977, p. 234. 3 7 1 A. K. Furr. G. S. Stoewsand, and D. J. Lisk, Arch. EnLliron. Health, 1976, 31, 87. "* R. L. Chaney, G. S . Stoewsand, C. A. Bache, and D. J. Lisk, J. Agric. Food Chem., 1978.26.992. '13 C. L. Heffron, J. T. Reid, D. C . Elfving, G. S. Stoewsand. W. A. Haschek. J. N. Telford, A. K. Furr, T. F. Parkinson, C. A. Bache, W. H. Gutenmann, P. C. Wszolek, and D. J. Lisk, J . Agric. Food Chem., 1980, 28,58. 374 H. Hamaguchi and P . Kuroda, Geochim. Cosmochim. Acfa, 1959, 17,44. 37s R. W . Boyle, 'The Geochemistry of Silver and its Deposits', Geol. Surv. Can. Bull., 1968, No. 160, Dept. of Energy Mines and Resources, Ottawa, Canada, 264 pp. ' 1 6 8. J . Fryer and R. Kerrich, AI. Absorpr. Newsl., 1978, 17, 4. 3 7 7 D. P. Kharkhar, K. K . Turekian. and K. K. Bertine, Geochim. Cosrnochim. A c f a , 1968, 32, 285. 17' K . H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-4/47. Springer Verlag. Berlin. 36y

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basic iron sulphates can scavenge and accumulate silver in soil horizons375and manganese oxides play the more important scavenging role, at least in stream sediments.379In clay minerals Agf may substitute for K+ in conditions of low acidity. Soil clay fractions of New Zealand soils contained more Ag (> 0.5-7 mg kg-I) than silt fractions (0.5-2 mg kg-1).380

Soil Contents. A bibliography of references to silver in plants and soils has been published381and a few early workers have reported the contents of silver in soils. mg Ag kg-I, and L o ~ n a m a a ~reports ~* S ~ a i n egives ~ ~ a range of <0.01-5 average values, for Finnish soils on different parent materials, ranging from 0.3-0.45 mg Ag kg-I. The average Ag content of ten Scottish topsoils on different parent materials was found to be 0.41 mg kg-1,69 not greatly different from the for soils in non-mineralized areas. The value of 0.30 mg kg-’ reported by Ag contents of 61 soils from 13 profiles in non-mineralized areas in New Brunswick, Canada, ranged from 0.1-7.8 mg kg-I, with a mean of 0.56 mg kg-’ 2 5 2 and of 5 muck soils from Ontario 0.4-0.92 mg kg-I, mean 0.67 mg kg-’ (see ref. 525). Soils, and organic-rich surface soils in particular, thus show an enrichment in silver relative to the crustal contents and average soil contents can therefore be tentatively assessed as approximately 0.4 mg kg-’. Gold and the Platinum Metals.-Geochemistry. The geochemistry of gold383-387 and the platinum metals388.389 have been reviewed. The abundance of gold in igneous rocks is in the range 0.5-5 pg kg-’ 3 8 7 with a mean value of about 1 pg kg-’ 376 and an average crustal abundance of about 2 S p g kg-1.39uFor the platinum metals abundances are not well established because of analytical problems at the low levels encountered in natural materials. Most analyses reported have been for Pd and Pt only. The values for crustal abundances quoted by G o l d s ~ h m i d t Au, , ~ ~ 5~; Jr, 0.4; Os, 0.4; Pd, 4; Pt, 2; Rh, 0.4, and Ru, 0.4 ,ug kg-I, and similar values by Vinograd~v,‘~’ have not been convincingly improved upon. The crustal abundance for Pd has been quoted as 0.01-0.02 pg kg-’.388 Values for various geological

37y

380

T. T. Chao and B. J. Anderson, Chem. Geol., 1974, 14, 159. R. J. W. McLaughlin, Geochim. Cosmochim. Acta, 1955,8, 109.

Tennessee Valley Authority, ‘Silver in Plants and Soils’, T.V.A., No. 15 14, 1976, 3 pp. J. Lounamaa, Ann. Bot. SOC.Vanamo., 1956, 29, 196 pp. 383 R. S. Jones and M. Fleischer, ‘Gold in Minerals and the Composition of Native Gold’, US Geol. Surv. Circ., 1969, No. 6 12, 117 pp. 384 R. S. Jones, ‘Gold Content of Water Plants and Animals’, US Ceol. Surv. Circ., 1970, N o . 625, 15 PP. 385 W. D. Ehmann, in ‘Handbook of Elemental Abundances’, ed. B. Mason. Gordon and Breach, London, 1971, p. 479. 3R6 D. Gottfried, J. J. Rowe, and R. I. Tilling, ‘Distribution of Gold in Igneous Rocks’. US Geol. Surv. ProJ Pap.? 1972, No. 121,42 pp. K . H. Wedepohl (ed.). ‘Handbook of Geochemistry’, 11-5/79, Springer-Verlag, Berlin. 388 T. Wright and M. Fleischer, ‘Geochemistry of the Platinum metals’, U S Geol. Surv. Bull., 1965. N o . 1 2 1 4 - 4 Addendum 1967. 389 K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-5/44 to 46 and 76 to 78, Springer-Verlag, Berlin. A. R. De Grazia and L. Haskin, Geochim. Cosmochim. Acta, 1964, 28, 559. 381

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En t i iron mental Chemistry

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Table 24391Noble metal contents of geological materials (pg kg-') Mean contents (pg kg-') Ir Pd 0.4 6 0.3 4

Au 2.8 0.75 3.5 2.9

8.5

5.3

Material

Basic and intermediate igneous rocks Acid igneous rocks Deep sea sediments Manganese nodules

materials are summarized391for Au, Ir, and Pd in Table 24 in which it is worth noting that the high Ir contents in manganese nodules resemble chondrite values. Weighted average values of 13 pg Pd kg-' and 32 ,ug Pt kg-' for ultrabasic rocks and 21 pg Pd kg-' and 30 pg Pt kg-' in basalts and gabbros have been pre~ented,~" whereas values for the Au, Ir, Pd, and Pt contents of U.S. Geol. Survey standard rocks PCC- 1, DTS- I , and W- I are also a ~ a i l a b l e . " ~ ~ " ~ It is generally considered that gold and the platinum metals are depleted in the acid igneous rocks during the processes of magmatic differentiation but may be enriched in accessory minerals in granitic pegmatites. Palladium and platinum are enriched in chromite-bearing rocks and in some serpentinites. These elements occur as the native metals. Gold also occurs in alloys with Cu, Ag, Pd, and Hg and in combination with Te. In addition the platinum metals are commonly associated with Cu and Ni in sulphide deposits and occur as arsenides, antimonides, selenides, and tellurides in basic and ultrabasic rocks. Analytical methods for the noble metals have been comprehensively s u r ~ e y e d The . ~ ~ occurrence ~ ~ ~ ~ ~ and biological effects of Pd and 0 s in the environment have been discussed by Smith et al.396who drew attention to the use, in the USA, of noble metal, catalytic after-burners in car exhausts and estimated that, in 1979, 1240 kg Pd would be dispersed in the atmosphere from this source.

Weathering and Mobility. Information is scant on the behaviour of the platinum metals in the weathering cycle but the literature relevant to gold has been reviewed387 and discussed in depth by Lakin et al."* Early experimental work reviewed by Krauskopf 399*400 indicated that acidic, chloride-rich water containing MnO,, Fe3+, and Cu2+could mobilize gold, while in alkaline conditions gold was soluble in the presence of HS-. Other ions forming stable gold complexes, including CN-, CNS-, and S @ - , play an important role in the mobilization and transport of J. H. Crockett, J. D. MacDougal. and R. C. Harriss, Geochim. Cosmochirn. Acta, 1973, 37, 2547. E. N. Gilbert. G . V. Veriovkin, and V. A. Mikhailov, J . Radioanal. Chern., 1976, 31, 365. J93 I. Ahmad, S. Ahmad, and D. F. C. Morris,Analysl (London), 1977, 102, 17. 394 F. E. Beamish, 'The Analytical Chemistry of the Noble Metals', Pergamon, Oxford, 1966, 608 pp. 39s F. E. Beamish and J . C. Van Loon, 'Recent Advances in the Analytical Chemistry of the Noble Metals', Pergamon, Oxford, 1972, 5 1 1 pp.

j9'

392

C. Smith, B. L. Carson, and T. L. Ferguson. in 'Trace Metals in the Environment. Vol. 4 Palladium and Osmium', Ann. Arbor Science Publishers, Michigan, 1978. 193 pp. 397 Commonwealth Bureau of Soils, 'Some References to Radium Beryllium, Silver, Gold, Uranium and Thorium in Soils and Plants', Annotated Bibliog., 1974, No. 1645. 19* H. W. Lakin, G . C. Curtin, A. E. Hubert, H. T. Shacklette. and K. G . Doxtader, 'Geochemistry of Gold in the Weathering Cycle', U S Geol. Sun.. Bull., US Govt. Printing Office, Washington, 1974, No. 1330.80 pp. 3yL) K. B. Krauskopf. Econ. Grol.. 195 1.46. 858. 4"" K. B. Krauskopf. 'Introduction to Geochemistry'. McGraw Hill, New York. 1967. '"1.

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gold.401The role of cyanide has particular relevance to the soil situation since some plants and soil fungi produced it. Gold cyanide may be the principal soluble form in soils and is probably taken up by plants. This aspect is also discussed by Lakin et Organic acids do not appear to dissolve gold, but may inhibit the precipitation of gold The transport of gold in iron-rich waters from weathered sulphide deposits and subsequent deposition with limonite has been observed403and gold enrichment been seen to occur in weathered basalts 391 and quartz-mica

Soil Contents. Insufficient data exist for the assignment of typical values of the soil contents of gold and the platinum metals, although contents for 3 Arctic island soils have been reported for gold and palladium: Au, mean 1.0 pg kg-',391 range 0.3-1.8 pg kg-' and Pd, mean 1.1 pg kg-I, range 0.7-1.6 ,ug kg-'.391 Gold are contents for soils and soil profiles, reported, for example, by Lakin et mainly from gold-bearing localities. Typical contents for normal soils can only be surmised from the abundance values reported for crustal rocks, which are themselves too scarce to be entirely reliable. The distribution of gold in soils is affected by two opposing factors. The first concentrates gold in upper horizons, humus layers, and forest mulls or litters by biological a c c ~ m ~ l a t i o nwhile , ~ ~ the ~ - ~second ~ ~ factor produces enrichment of the basal horizons by gravitational mechanisms facilitated by the high density of gold. Gold has also been associated in soils with iron hydroxides and clays4" and with secondary iron minerals.409Forest mull samples have widely been used as an aid to gold The use of plants as indicators of gold mineralization has also been s t ~ d i e d . ~ I ' - ~ ~ ~ The gold contents of waters, plants, and animals have been reviewed comprehensively by Jones.384The gold contents of plant standard reference materials, have been d i s c u ~ s e d and ~~~ those ~ ~ of ' ~ other biological standard reference materials by Nadkarni and Morrison.416Schiller et aL414have discussed the contents of plants from gold-bearing areas in Slovakia. Palladium has also been reported4I7as being H. W. Lakin, G. C . Curtin, and A. E. Hubert, in 'Geochemical Exploration', ed. R. W. Boyle and J. I. McGerrigle, Canadian Inst. Min. and Metall., 197 1, 11, 196. 402 H. L. Ong and V. E. Swanson, Colorado Sch. Mines Quart., 1969,64,395. '03 A. R. Kinkel and F. G. Lesure, in 'Residual Enrichment and Supergene Migration of Gold, Southeastern United States', US Geol. Surv. Prof. Pap., 1968, No. 600-D. 174. 404 F. G. Lesure, Econ. Geol., 1971, 66, 178. 405 G. C. Curtin, H.W. Lakin, G. J. Neuerberg, and A. E. Hubert, US Geol. Surv. Circ., 1968, No. 562, 1 1 PP. 406 G . C. Curtin, H. W. Lakin, and A. E. Hubert, US Geol. Surv. ProJ Pap, 1970, No. 700-C, C127. 407 Yu. A. Aferov, V. G. Zvyagin, N. V. Roslyakova, N. A. Roslyakov, L. L. Shabynin, and I. N. Epov, Vopr. Geol. Pribaikal, Zabaikal, 1968, 3, 146. '08 L. V. Razin and I. S. Rozhkov, 'Geochemistry of Gold in the Weathered Crust and Biosphere of Gold Deposits of the Kuranakh Type', Nauka, Moscow, 1966. '09 Kh. Aripova and R. M. Talipov, Uzb. Geol. Zh., 1966, 10. 45. 4 1 0 W. L. Rice, US Bur. Mines Rep. Inv., 1970, 8425, 14 pp. 4 1 1 H. L. Cannon, Science, 1960, 132, 591. 4 1 2 H. L. Cannon, H. T. Shacklette, and H. Bastron, U S Geol. Suro. Bull., 1968, No. 1278 A, 1. 4 1 3 C. A. Girling, P. J. Peterson, and M. J. Minski, Sci.Total Enoiron., 1978, 10, 79. 4 1 4 P. Schiller, G. B. Cook, A. Kitzinger, and E. W O l f l , A n a l j (London), ~ 1972, 97, 601. M. J . Minski, C . A . Girling, and P. J. Peterson, Radiochern. Radioanal. Left., 1977, 30, 179. 4 ' 6 R. A . Nadkarni and G. H. Morrison, J . Radioanal. Chem., 1977,38,435. 4 1 ' E. L. Kothny, Plant Soil, 1979, 53, 547. 401

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taken up by plants, with plant-ash/soil content ratios generally > I , and water extraction of soils has been used t o assess the uptake of Io6Ru by clover.418 An annotated bibliography”’ with some references to gold (and silver) in soils and plants is available. 11 Mercury

The recent expansion in the literature on mercury and its determination stems largely from the interest in environmental effects although considerable importance still attaches to the use of mercury as a guide in mineral prospecting. This expansion has been facilitated by the current availability of sensitive atomic absorption spectrometric methods of analysis which have been reviewed by many The occurrence and the effects of mercury in the environment and on man have also been comprehensively s ~ r v e y e d . ~Reviews ~ ~ - ~ ~of~ the general geochemistry of mercury have also been p ~ b l i s h e d . ~ ” ~ ~ ~ ’ Geochemistry.-Mercury occurs in nature principally as cinnabar and as complex sulphides with zinc, iron, and other metals, but only to a small extent as native metal. Mercury can also replace Ag, Au, Ba, Bi, Cd, Pb, Sr, and Zn in other minerals.438 The average abundance of mercury in the earth’s crust has been calculated to be 0.08 mg kg-’.438 This value may be somewhat high in view of more recent work by Ehmann and L ~ v e r i n gwhich , ~ ~ ~suggests that a value of about 0.02 mg kg-I would be more realistic. Recent measurements of the average contents of sedimentary rocks in the USA, sandstones 0.007, shales 0.023, and limestone 0.009 R. K. Schultz and K. K. Babcock, Soil Sci., 1974, 117, 171. J . D. Brooks and W. E. Wolfram, Chem. Eng. News, 1970,48,37. 42n D. C. Manning, Atom. Absorpt. News/., 1970, 9, 97. 4 2 1 V. G. Feklichev and V. P. Pashutin, in ‘Metod Mineral, Issled.’, ed. E. I . Semenov, Nauka, Moscow, 1971, p. 38. 4 2 2 F. Yamauchi and Y. Katsumo, Soda To Enso, 197 I , 22,303. 423 R. S. Reiners, W. D. Burrows, and P. A. Krenkel, J . Water Pollut. Control Fed., 1973, 45, 814. A. M. Ure, Anal. Chim. Acta, 1975, 76, 1. 4 2 5 J. G. Saha, Residue Rev., 1972, 42, 103. 4 2 6 Anon., ‘Mercury Contamination in Man and his Environment’, lnt. At. Energy. Tech. Rep. 137, Vienna, 1972, 181 pp. 42’ I. R. Jonasson. in ‘Mercury in the Natural Environment. A Review of Recent Work’ Geol. Surv. of Canada, Paper 70-57, Ottawa, Canada, 1970, 39 pp. 42R R. Hurtung and B. D. Dinman, ‘Environmental Mercury Contamination’ Ann Arbor Science, 1972, 349 pp. 4 2 y E. L. Kothny, in ‘Trace Elements in the Environment’. ed. E. L. Kothny, Am. Chem. SOC.1973, p. 48. 4 3 ” M. E. Barnes (ed.), ‘Mercury Contamination in the Natural Environment’, PB192910, US Dept. of Interior, Washington, 1970. 4 3 ’ R. Rehfus, ‘Mercury Contamination in the Natural Environment’. Office of Library Services, US Dept. of Interior, Washington, 1970. 32 pp. 4 3 2 R. A. Wallace, W . Fulkerson. W. D. Shults, and W . S. Lyon, ‘Mercury in the Environment - the Human Element’, Natl. Tech. Inf. Service, ORNL-NSF-EP-I. US Dept. Commerce. 1971. h l pp. 4 3 3 E. A. Jenne and W. Sanders, J . Water Pollur. Control. Fed., 1973. 45, 1952. 4 3 4 D. Taylor, ‘Mercury as an Environmental Pollutant: A Bibliography’, ICI Brixham Laboratory. England, 3rd Edn. 1973. ‘j5 Anon. U S Geol. Surv. ProJ Pap., US Govt. Printing Office, Washington, 1970. No. 713. I. R. Jonasson and R. W. Boyle, Can. Min. Metall. Bull., 1972, 65, 32. 4’7 1. R. Jonasson, J. J. Lynch. and L. J. Trip, Geol. Surtl. Can. Pap., 1973. No. 73-21. 438 K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-5/80. Springer-Verlag, Berlin. 439 W. D. Ehmann and J. F. Lovering, Geochirn. Cosmochirn. Acta, 1967, 31. 357. 418 41y

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mg Hg kg-1,440are lower than those for the Russian plain of 0.039, 0.035, and Other recent mean Hg values for sedimentary 0.031 mg Hg kg-’, re~pectively.~~’ rock contents include 0.513 and 0.129 mg kg-’ for different types of Canadian shales, 0.04 mg kg-I for world-wide limestones and dolomites, and 0.05 mg kg-I for sandstones, arkoses, and conglomerates.442Soils and marine sediments can be enriched relative to consolidated sedimentary rocks by a factor of ten,44’ while stream sediments may also be enriched by factors of 2-12 times over those of the parent Weathering and Mobility.-Cinnabar, HgS, is resistant to the normal processes of oxidation and weathering and is at the same time extremely insoluble. Where, however, oxidation of other sulphide ores occurs the resultant ferric sulphate has been shown experimentally, to facilitate the oxidation of cinnabar, particularly in the presence of sodium That this, or a similar process occurs in nature, however slowly, is evidenced by the formation of secondary deposits of cinnabar and by the enriched soil contents in the vicinity of major mineral deposits in British Colombia to the extent of 10-20 mg kg-’ compared to the uncontaminated soil from a base-metal contents in the range 0.25-2.5 mg kg-’.444 Similar mining area in Great Britain, indicated a maximum content of 1.78 mg Hg kg-’ in the flood plain of a river polluted by mine-waste compared to background soil content of 0.093 mg kg-I. The solubility of elemental mercury in natural waters is low, ca. 0.025 mg kg-1,446but the presence of chloride in oxygenated water greatly increases its s o l ~ b i l i t y . ~ ~ ’ The immobilization of mercury in soils is a consequence of its ability to form stable complexes with organic matter and to its adsorption on iron oxides, clay minerals, and soil colloids. A discussion of these aspects comprehensive up to 1970, has been presented by J o n a s ~ o n , ~with ” literature too voluminous to repeat here. The formation of strong complexes of mercury with humic and fulvic acid fractions of soil has been c ~ n f i r m e d , ~although ~ * * ~ ~in~ salt water only the humic acid, but not the fulvic acid, from soil or peat was found to complex mercury.45oBy exposing surface soils to mercury vapour L a ~ ~ d was a ~ ~able ’ to show that the mercury absorbed was retained as an organic complex. Soil Contents.-The occurrence and distribution of mercury in different soils and soil profiles reflects both these complex interactions of mercury with organic material and clay minerals. It has usually been found that top soils and surface J. M. McNeal and A. W . Rose, Geochim. Cosmochim. Acta, 1974, 38, 1759. N. A. Ozerova and N. Kh. Aidin’yan, Lithol. Miner. Resour. ( U S S R ) , 1966, 312. 442 E. M. Cameron and I. R. Jonasson, Geochim. Cosmochim. A c ~ a 1972, , 36, 985. 443 A. A. Saukov and N. Kh. Aidin’yan, Akad. Nauk, SSSR, Trudy. Inst. Geol. Nauk No. 39. Mineral. Geokhim., Ser. No. 8, 1940, p. 37. 444 H. V. Warren, R. E. Delavault, and J. Barakso, Econ. Geol., 1966, 61, 1010. 4 4 s B. E. Davies, Geoderma. 1976, 16, 183. 446 J. D. Hem, in ‘Mercury in the Environment’, U.S. Geol. Surv. Prof. Pap., 1970, No. 7 13, 19. 447 T. Anfalt, D. Dyrssen, E. Ivanova, and D. Jagner. Szien. Kem. Tidskr., 1968,80, 340. 44” V. Cheam and D. S. Gamble, Can. J. Soil Sci.. 1974, 54, 413. 449 P. Strohal and D. Huljev, in ‘Nuclear Techniques in Environmental Pollution’, IAEA Vienna. 1971, p. 439. 4 5 0 G. E. Millward and J. D. Burton, M a r . Sci.Cornmun., 1975, 1. 15. 4 5 ‘ E. R. Landa. Geochim. Cosmochim. Acta. 1978. 42. 1407. 440 44’

152

En cironmen fa1 Chemistry

horizons with their higher organic matter content have the highest concentration of m e r ~ ~ r yIn. ~comprehensive ~ ~ * ~ ~ ~studies of 273 Swedish soils, topsoil contents exceeded subsoil contents by factors of 5-10. At low pH (4-7) mercury was mainly adsorbed in humus, but at higher pH was increasingly adsorbed by soil minerals.452 Similar conclusions were drawn in a study of Dutch soils.454A significant relationship between mercury contents and organic matter has been shown in soils from mercuriferous regions in British Colombia.455 In some Canadian chernozems and luvisols, however, no significant difference was observed between A and C horizons, and mercury contents correlated, not with organic carbon, but with clay contents.456Other studies in the same country457have found lower mercury contents in surface horizons of chernozems than in C horizons, whereas for eluviated soils they were lowest in A and highest in B horizons. What may be regarded as typical profile distributions for field, paddy, and forest soils on igneous (acidic t o basic) parent materials in Kyushu, Japan are given by Gotoh et al.458and generally show highest contents in A horizons decreasing down the profile t o the C horizon. In a few cases, however, mercury contents were uniform down the profile. This situation has also been observed exceptionally in Scottish soil profiles (Ure and Berrow, unpublished) in which elevated lead and other heavy-metal contents were also present in the basal horizons. This implies that the mercury input occurred at the lower levels and migrated upwards with eventual loss to the atmosphere as suggested by Dudas and P a w l ~ k . ~Mechanisms ~’ for upward transport of mercury in pellicular waters, as metal ions or as humus complexes, have been suggested in addition to migration as mercury v a p o ~ r . ~ ~ ~ Enrichment factors of 12-34 relative to TiO,, have been reported.458In these soils mercury contents were significantly correlated with those of carbon but less so with cation-exchange capacity and clay contents and negatively with pH. In Morrow (USA) plot soils sampled over 63 years, however, no correlation with carbon content was The adsorption of phenyl mercuric acetate by soil colloids occurred in the order kaolinite + allophane < m ~ n t m o r i l l o n i t e ~and ~ ’ the mercury was more easily leached from allophane than from r n ~ n t m o r i l l o n i t e . ~ ~ ~ While mercury can, then, exist in soils in a variety of solid phases, such as primary mineral sulphide, complexed with organic material, adsorbed on clay minerals, and in dissolved forms, it has also been shown to exist in volatile phases including inorganic mercury Recent studies have shown that the evolution of elemental mercury by reduction of the mercuric ion is mediated by the humic acid content and the pH of soils.465The loss of volatile mercury from soils A. Anderson, Grundforbattring, 1967, 20, 95. A. Anderson, Oikos, 1967, Suppl. No. 9, 13. 454 P. Poelstra, M. J . Frissel, N. Vander Klugt, and D. W. Bannink, Neth. J . Agric. Sci., 1973, 21, 77. 4J5 M. K. John, C. J. Van Laerhoven, V . E. Osborne, and I. Cotic, Water, Air Soil Pollut., 1975, 5, 213. 456 H. I. Gracey and J . W. B. Stewart, Can. J . Soil Sci., 1974, 54, 105. 4 5 7 M. J. Dudas and S. Pawluk, Can. J . Soil Sci.. 1976, 56,413. 4 5 8 S. Gotoh, S. Tokudome, and H. Koga, Soil Sci. Plant Nutr.. 1978. 24, 391. 459 J. R. Jonasson, Nature (London), 1973, 241,447. 46u R. L. Jones and T. D. Hinesly, Soil Sci. SOC.A m . Proc.. 1972, 36,921. 4 6 ’ S. Aomine, H. Kawasaki, and K. Inoue, Soil Sci. Plant Nutr., 1967, 13, 186. 462 K. Inoue and S. Aomine, Soil Sci. Plant Nutr., 1969, 15. 86. 463 A. E. Hitchcock and P. W. Zimmerman, Ann. N.Y. Acad. Sci., 1957.65,474. 464 Y. Kimura and V. L. Miller, J . Agric. Food. Chem., 1964, 12, 253. 465 J. J. Alberts. J. E. Schindler. R. W. Miller, and D. E. Nutter, jun., Science, 1974, 184, 894. 452

4J3

The Elemental Constituents of Soils

153

treated with inorganic mercury compounds is a function of the solubility of the compound and perhaps of the soil texture.466 Other addition studies of volatility losses in soils have been made.451,467+468 The measurement of the mercury contents in the air above and in the soil has been widely used as an aid in mineral prospecting.469In a discussion of the soil balance for mercury in Dutch bulb soils, losses were attributed to evaporation as well as to leaching of mercury,454and a study of soil-profile distributions and mercury contents of particle-size separates from Canadian soils also suggest loss of mercury to the atmosphere from surface horizons.457The formation of methylmercury compounds by biological especially in aquatic environments is now well established and similar processes have been indicated in terrestrial Methylmercury has also been found to occur above soils treated with mercuric chloride.472Methylation was found to be directly proportional to clay and moisture content, to temperature, and to mercury content. Demethylation processes also occur 466 and in paddy field organo-mercurial pesticides are largely converted to inorganic compounds within eight years.473Other workers suggest that the production of methylmercury in most agricultural soils is too small to present significant problems. This has been demonstrated by incubating soils which had been doped with organic and inorganic mercury compounds.473It has, however, been estimated that up to 30% of the mercury in soils is present as volatile organic Although, for many agricultural soils, problems of industrial pollution by mercury are small and the mercury contents are determined largely by geological factors,475for soils in urban or industrial areas mercury contents can be enhanced. Soils in rural, residential, and industrial areas and in the vicinity of an airport have been compared and show higher mercury contents in the latter two environments476 with an industrial area average of 0.14 mg kg-' compared with a rural average of 0.1 1 mg kg-'. Garden soils from areas of the UK with Hg contents, attributed to geological factors, ranging from 0.25-15 mg kg-I have been reported,477but Scottish garden soils, even where calomel was extensively used as a fungicide in brassica cultivation, did not exceed 1 mg kg-' (Ure and Berrow, unpublished). High Hg contents in the soils from golf course greens (mean 53 mg kg-I) and turf (mean 57 mg kg-') have, however, been attributed to the use of mercurial fungicides.47x Other soil additives, of which sewage sludges are perhaps the most important, can

R. D. Rogers, J . Environ. Qual., 1976, 5, 454. E. R. Landa, Soil Sci., 1978, 126, 44. 46m E. R. Landa, Soil Sci., 1979, 128, 9. 469 L. M. Azzaria, Quebec (Prov.) Dep. Nat. Resour., 1973, No. S-136. 4 70 S. Jensen and A. Jernelov. Nature, (London), 1969, 233, 753. 4 7 ' W. F. Beckert, A. A. Moghissi, F. G. F. Au, E. W. Bretthauer, and J. C. McFarlane. Nature, (London), 1974,249,674. 4 7 2 R . S. Braman and D. L. Johnson, in Proc. 2nd Ann. NSF RANN Trace Contaminants in the Environment, ed. E. D. Copenhauer, 1974, Oak Ridge Natl. Lab. Tennessee. USA, 1974, p. 75. 4 7 3 H. G. Van Fassen, Plant Soil, 1976, 44, 505. 4 7 4 B. G. Weissberg, Econ. Geol., 1971, 66, 1042. 475 J. G. Mills and M. A. Zwarich, Can. J . Soil Sci., 1975, 5 5 , 295. 476 D. H. Klein, Environ. Sci. Technol., 1972, 6, 560. 4 7 7 H. V. Warren and R. E. Delavault, Oikos, 1969, 20. 537. 478 A. J. MacLean, B. Stone. and W. E. Cordukes, Cmn. J . Soil Sci., 1973, 53. 130. 46b 467

154

Environmental Chemistry

contribute to soil c o n t e n t ~ ~ ' ~but - ~ ~most ' other fertilizer materials have low mercury contents. The combustion of fossil fuels such as coal make a major contribution to the atmospheric mercury burden 482,483 and as a consequence some 1.2 g ha-' yr-' of mercury is delivered to soil by rain.484In urban soils with a range of 0.24-1.5 mg kg-' the mercury content correlated with the particulate f a l l - o ~ t . ~ ~ ~ The complex relationships involved in the cycles of mercury in the environment have been quantitatively assessed by K ~ t h n y A. ~comprehensive ~~ review of the effects of mercury in the Canadian environment has also been made (see ref. 824). Ranges and mean contents for some 3049 soils are listed in Table 25 and cover a wide range of countries. Mercury contents range from 0 . 0 0 4 4 . 6 with an average 0.098 mg kg-I. Other values reported, but not quoted in Table 25, include an average of 0.03 mg kg-' in N. Dakota and a topsoils (0-3") range of 0.05-0.10 mg kg-' in Eastern United States.486Surveys of Israel soils and waters have been made487 and the mercury and iodine distribution in Scandinavian forest soils investigated.488 The most important biological effect of mercury is its toxicity to animals and man, both in its inorganic form and more especially in organic forms such as methylmercury. Although uptake of mercury by plants grown in mercury treated soils has been d e m ~ n s t r a t e d the , ~ ~amounts ~ ~ ~ ~ ~entering the food chain by this route are generally minimal. Smart 491 in reviewing the literature on the contamination of crops with mercury used in normal agricultural practice concluded that mercury residues seldom exceed 0.1 mg kg-' in apples, tomatoes, eggs, and meat, 0.5 mg kg-' in potatoes, and 0.02 mg kg-* in wheat and barley. Wheat and barley have been shown to contain 0.008-0.016 mg Hg kg-' whether grown from treated or untreated seed,492although significant uptake by wheat grown from treated seed has been reported.493 Mercury levels in cereals4y4 and other crops have been The mercury burden of eight tree and shrub species from rural areas (USA) was found to exceed slightly 0.5 mg kg-' and only one was in excess of 1 mg kg-1.495 The principal impact of mercurial seed dressings has in fact been on seed-eating A. Anderson and K. 0. Nilsson, Ambio, 1972, 1, 176. A. Anderson, Grundforbattring, 1967, 314, 149. 481 J . C. Van Loon, Environ. Pollut., 1974, 7, 14 1. 482 0. I. Joensuu, Science, 1971, 172, 1027. 483 C. F. Billings and W. R. Matson, Science. 1972, 176, 1232. 484 A. Anderson and L. Wiklander, Grundforbattring, 1965, 18, 171. 485 M. S. Buraiky and C. J . Ritter, Environ. Geol., 1976, 1, 295. 486 J. L. Sell, F. D. Dietz, and M.L. Buchanan, Arch. Environ. Contam. Toxicol., 1975, 3. 275. 487 S. M. Siegel and B. Z. Siegel, Water, Air Soil Pollut., 1976. 5. 263. 488 J . L6g and E. Steinnes, Proc. Symp. Nuclear Technology in Environmental Pollution Vienna, 1970, International Atomic Energy Agency, Vienna. 197 I , p. 249. 4ny M. K. John. Bull. Environ. Contam. 7oxicol., 1972, 8, 77. duo A. J. MacLean. Can. J . Soil Sci., 1974, 54, 287. 4 9 ' N. A. Smart, Residue Rev., 1968, 23, 1. 492 J . G. Saha, Y. W. Lee, R. D. Tinline, S. H. F. Chinn, and H. M. Austenson, Can. J. Plant Sci.. 1970. 50, 597. 493 P. E. James, J. V. Lagerwerff, and R. F. Dudley, in 'Identification and Measurement of Environmental Pollutants', Proc. Int. Symp., Ottawa, 197 1. 4 y 4 R. Tkachuk and F. D. Kuzina, J . Sci. Food. Agric., 1972, 23. I1 83. 495 W. H . Smith, Science, 1972. 176. 1237. 496 K. Borg, H. Wanntorp, K. Erne. and E. Hank0.J. Appl. Ecol. Suppl. 3, 1966, 17 1. 4 y 7 K . Borg, H. Wanntorp. K. Erne. and E. Hanko. Swedish WildliJie. 1969,6, 299. 4 y x S. Tejning. Oikos. 1967, 18. 334.

47y

480

155

The Elemental Constituents of Soils Table 25 Mercury soil contents (mg Hg kg-I) Soils 273 soils, Sweden 14 soils, Africa 200 topsoils, Sweden 1 topsoil, France 3 topsoils, Sweden 9 12 soils, USA 2 soils, USA 9 1 soils, rural, USA 86 soils, industrial, USA 70 soils, residential, USA 40 soils, Austria, profiles 8 topsoils, Holland 4 topsoils 13 topsoils, Scotland 27 soils, Canada, A horizons 233 soils, Canada, 65 profiles 65 topsoils, Canada Topsoils, 0-3” E. USA 109 topsoils, Scotland 354 topsoils and profile soils, Scotland 13 A horizon, Japan 39 topsoils, Canada 296 topsoils, Ontario, Canada 5 3 topsoils, England and Wales 23 soils, Scotland, 4 profiles 173 soils, Canada, 53 profiles 3049 Soils

Range 0.004-0.9 22 -

0.020-0.290 -

<0.010-4.6 0.20-0.24 -

0.005-0.340 0.07-0.35 0.039-0.07 1 0.09-4.26 <0.005---0.036 -

Mean 0.06 1 0.023 0.070 0.050 0.030 0.1 12 0.22 0.1 1 0.14 0.10 0.095 0.133 0.054 0.138 0.022 0.08 1 0.064

0.026-0.1 1 1 0.05-0.10 0.O 3-0.3 7 0.to (0.0 1- 1.7 1 0.13 0.064-0.459 0.197 0.033 0.02-4.053 0.01-1.14 0.1 1 0.008-4.19 (median 0.04) 0.01-0.20 0.094 0.059 0.005-0.1

R eJ 452 452 453 453 453 77 a 476 476 476 b 454 c

d 456 e e

f* g g

458 475 h 299* 122 1

Mean Content 0.098 mg Hg kg-’

* Not included in Mean “ I . K. Iskandar, J. K. Syers, L. W. Jacobs, D. R. Kennedy, and J. T. Gilmour, Anaivst (London), 1972, 97, 388; J. Wirnrner and E. Haunold, Bodenkultur, 1973, 24, 25: J. W. Hamm and J. W. B. Stewart, Commun. Soil Sci. Plant Anal., 1973,4,233; A. M. Ure and C. A. Shand, Anal. Chim. Acta., 1974, 72,63; ‘J. A. McKeague and B. L. Kloosterman, Can. J. Soil Sci.. 1974,54,503: I G . B. Wiersma and H. Tai, Pestic. Monitor. J., 1974, 7, 214: g A. M. Ure and M. L. Berrow, unpublished results: R. Frank. K. Ishida, and P. Suda, Can. J. Soil Sci., 1976, 56, 181; J. A. McKeague and M. S. Wolynetz, Geoderma, 1980, 24, 299 12 Boron, Aluminium, Gallium, Indium, and Thallium

Boron.-Geochemistry. Boron is one of the less abundant elements in the earths crust, 10 mg kg-1.75 Large quantities are concentrated, however, in deposits of hydrated borate minerals formed in closed basins and under arid conditions. The B content of most minerals and rocks varies over a wide range due, probably, to the generally volatile nature of B-compounds. If the amount of B available during the crystallization of major minerals is too low to allow for the formation of B-minerals such as tourmaline, B will replace major elements in these minerals. Tourmaline can contain 2.8-3.6% B and is the most important of the B-minerals. Phyllosilicates in rocks contain more B than other silicates and B contents in rocks tend to increase in the sequence basic + intermediate -+ granitic. The B contents of normal granitic rocks varies over a wide range, however, from about 0.3-300 mg kg-I with much higher contents in tourmaline granites.499 Boron is often high in coal ashes and 4yy

K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11- 1 /5, Springer-Verlag. Berlin.

156

Environmental Chemistry

particularly so in those from New Zealand where levels of up to 9000 mg kg-' have been r e p ~ r t e d . ~ " Weathering and Mobility. During weathering, the rock-forming silicates containing B, such as alkali feldspars and micas, break down and release B into solution. Borate minerals are relatively soluble but boron silicates such as tourmaline are resistant to weathering. Boron is present in water as the B(0H); ion, undissociated boric acid B(OH), and as NaB(OH), (in sea water) and its concentration in water is primarily controlled by adsorption or incorporation into illite minerals. Illite and other micas can take up boron in a non-exchangeable form, a major portion of the adsorbed boron being incorporated into the illite structure.499 Because of the solubility and mobility of boric acid, B is accumulated in sea water, 4.5 mg kg-I, and marine sediments. Argillaceous sediments (clays and shales) are by far the most abundant sedimentary rocks and are the important B carriers. A mean value of 100 mg B kg-' for clays and shales has been computed by Harder,5o1this value being about 10 times the average for B in igneous rocks. A good correlation ( r = 0.976) has been reported between the B content of rocks and associated soils.'02

Soil Contents. An overall mean of 38.3 mg B kg-' in 3731 soils from various parts of the world, with a range of 0.9-1000 mg B kg-I, is reported in Table 26. The median boron content of soils has been reported by Bowen', to be 20 mg kg-', with a range of 2-270 mg kg-I. Swainey3has reported that the total B in most soils is in the range 2-100 mg kg-I, while Jackson reports a range of 4-98 mg kg-I with an average of about 30 mg kg-I. In Russia two distinct regions can be distinguished on the basis of the B contents of their soils.68The tundra podzolic soils and grey forest soils of the ancient plains have low levels of B, and the sierozems, solonetz, and red-earth desert soils of the arid zone have high B contents. The B contents of 173 New Zealand topsoils range from < 1-70 mg kg-I, mean 21.3 mg kg-'.503 Topsoils with high levels of B were rendzinas, saline grey soils, and brown-grey earths. Topsoils with low levels of B are brown granular clays, red and brown loams, brown granular loams, organic soils, and recent soils from volcanic ash. A survey of investigations on boron in soils and plants carried out in Poland has been published by Boratynski et al.256 Boron is not essential to animals but is required for the growth of plants. The availability of soil boron is reduced by liming and where soils are deficient in available B, it is added to fertilizers in a soluble form. On sandy soils low in humus, however, a water soluble boron fertilizer will only have a small residual effect, as it is rapidly washed out of the soil if the season is wet.5'' Crops such as brassicas,

'""R. Soong and M . L. Berrow. N.Z. J . Sci.,1979. 22. 229. '"I

H. Harder. Nuchr Ahad. Wiss. Gottingeti, Math.-Ph-vs. Kl. 2. 1959, 67.

'"'J. Maurice, A m . Agron., 1973. 24. 465.

"' N . Wells and J . S. Whitton, N . Z . J . Sci.. 1977, 20. 317. '04

M. Naidenov and A. Travesi, Soil Sci.. 1977. 124. 152.

"' N. G. Zyrin, Sou. Soil Sci., 1968. (7). 933.

The Elemental Constituents of Soils

157

Table 26 Boron soil contents (mg B kg-’) Range Soils 3-300 123 topsoils, Finland 15-92 360 soils, China, 1 1 1 profiles < 10-200 19 soils, Germany, 4 profiles 7.5-40 30 topsoils, India 45- 124 108 topsoils, Canada 0.9-4 1.6 20 soils, USSR, 4 profiles 58 topsoils, USSR 210 topsoils, Burma 16-120 68 soils, Burma, 17 profiles 128 topsoils, USSR 25-363 30 soils, California, 10 profiles (20-300 863 topsoils, USA 2.7- 18.2 110 soils, Cameroon, 18 profiles 12-72 5 1 soils, Israel, 12 profiles 14-70 36 soils, Israel, 10 profiles 2.1-39 64 soils, Poland, 12 profiles 13.1-58.5 10 topsoils, Rajasthan, India 28-94 325 topsoils, France 50-1000 65 soils, India, 9 profiles 6-78 25 soils, Georgia, USSR, 8 profiles 2.8-53.1 56 soils, Rajasthan, India 0.94- 129.3 800 topsoils, European USSR 173 topsoils, New Zealand < 1-70 7-7 1 227 topsoils, England and Wales 3731 Soils Overall Mean 38.3 mg kg-’

Mean 57.6 46 34.7 33.1 77.5 15.5 33.1 32.6 39.8 32.8 74.5 34 5.2 33.9 38.5 11.3 28.9 49.9 288.6 36.3 22.0 25.2 21.3 (median 33)

R4 382 a 8 b C

d

21 505 e 77 23

f g

h I

513 j k 1 rn 502 299*

* Not included in Mean C. L. Fang, T. C. Sung, and Yeh Bing. Acfa Pedologica Sinica., 1963, 11, 130; B. L. Baser and S . N. Saxena, J . Indian SOC.Soil Sci., 1967, 15, 135; ‘U. C . Gupta, Proc. Soil Sci. SOC.Am., 1968, 32,45; A. N. Gyul’akhmedov and Ya. M . Peysakhov, Sou. Soil Sci., 1968, (6), 801; F. T. Bingham, R. J. Arkley, and N. T. Coleman, Hilgardia, 1970,40, 193;/S. Ravikovitch and J . Navrot, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp, 1-12: J. Navrot and S. Ravikovitch, Unnumbered Publ. Hebrew Univ. Jerusalem Fac. Agric., 1972, 20 pp, 13-20; W. Dzieciolowski and Z . Kocialkowski, Rocz. Glebozn., 1973, 24, 24 1 ; F. La1 and T. D. Biswas, J. Indian SOC.Soil Sci., 1973, 21, 455; j U . S. Shukla and K. G . Prasad, Indian J. Agric. Sci., 1973, 43, 934; N. G. Zyrin, G . V. Motuzova, and T. A. Sokolova, Pochuouednie, 1973, 7, 149; ’N. R. Talati and S . K. Agarwal, J. Indian SOC.Soil Sci.,1974, 22, 262; N. G . Zyrin and Yu. N. Zborishchuk, Sou. Soil Sci., 1975, (7). 330

which have a high boron requirement, often need boronated fertilizers, whereas cereals and grasses have a low boron requirement. Boron is toxic in excess, however, and toxicity problems have arisen where crops in arid areas have been irrigated with B-rich waters. Water-extractable B has been found useful as a diagnostic tool in assessing B deficiency in crops.5o6Recent work on the role of boron in plant growth has been reviewed by D ~ g g e r . ~ ’ ~

Aluminium.-Geochemistry. The only stable valence state of A1 in natural mineralogical systems is the A13+ cation. Aluminium plays a dual role in the F. T. Bingham, in ‘Trace Elements in the Environment’, ed. E. L. Kothny, Am. Chem. SOC., Washington, DC, 1973, p. 130. W. M. Dugger, in ‘Trace Elements in the Environment’, ed. E. L. Kothny, Am. Chem. SOC., Washington, DC, 1973, p. 1 12.

Environmenta I Chernistrji

158

rock-forming silicate minerals ( i ) as an octahedrally and (ii) as a tetrahedrally co-ordinated cation in minerals such as amphiboles, pyroxenes, and phyllosilicates. It is also a major component of feldspars. The most important structural units of the alurninosilicate minerals are the silica and alumina tetrahedras which are linked to form the framework of different minerals. Because A13+ fits poorly into four-fold co-ordination, the larger the number of alumina tetrahedras in a structure, the weaker it will be. Structures with A1 octahedras, as in gibbsite, Al(OH), form a much more stable structure and this is consistent with the fact that gibbsite is the end-product of the weathering of biotite, muscovite, and other aluminosilicates. Aluminium is the third most abundant element in the earth's crust and the A1 content in many rocks averages around 15% Al,O, (7.9% Al).

Weathering and Mobility. In general the solubility of A1 in weathering processes is low, which promotes its retention in the weathering products of low solubility. These products are among the most stable minerals in the zone of weathering and A1 is therefore conserved. Aluminium ions released by weathering from feldspars or other aluminosilicates attain a hydrated form almost immediately, Al(H,0),.508

Soil Contents. Aluminium is a major constituent of soils and in a survey of 1770 soils from various parts of the world the overall mean content was 6.65% with a range of 0.07-20.3% (Table 27). These values are similar to the median content of 7.1% and range of 1--30% Al quoted by B ~ w e n . 'A~ better understanding of soil A1 has had profound effects on the interpretation of many aspects of soil chemistry.509Once released by weathering the trivalent A1 ion assumes octahedral Table 27 Aluminium soil contents (Yo Al)

Soils 18 soils, USA, 6 profiles 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 108 soils, Ghana, 19 profiles 195 soils, California, 50 profiles 37 soils, Poland, I3 profiles 863 topsoils, USA 29 soils, Portugal, 6 profiles 37 soils, New Zealand, 10 profiles 285 soils, Canada, 8 1 profiles 10 topsoils, Scotland 23 soils, Scotland, 4 profiles 12 topsoils, S.E. USA

Range 0.39- 12.4

-

4.75-10.80 0.90-20.3 1.20-8.46 2.94-7.99 0.07-> 10.0 1.15-1 1.60 7.2- 10.0 0.1-1 1.5 4 .O-7.6 4.1-9.6 0.79- 14.55

Mean 6.40 9.03 7.77 8.16 5.03 5.62 6.60 4.37 8.78 6.2 5.69 7.44 7.75

R eJ 228 4 92 6 a

b 77 C

d

e 69 122 805

1770 Soils Overall Mean 6.65% AI ' G. R. Bradford. R. J. Arklev. P. F. Pratt. and F. L. Blair. Hikardia., 1967, 38, 541; ' B . Dobrianski and J. Glinski. Rocz. Glehozn., 1971. 21, 365: ' A. S. Coutinho. A. J . Das Texiera, E. M. De Sequeira. and M. D. Lucas. Agron. Lusif., 1973. 33, 257; " L . F. Molloy and L. C. Blakemore, N . Z . J. Sci.. 1974, 17, 233; ('J. A. McKeague, J . G . Desjardins, and M. S. Wolynetz. Agric. Canada, Ottawa 1979. LRRI Publ. 2 1

50R 5n9

K. H. Wedepohl (ed.). 'Handbook of Geochemistry'. 11- 1 /13. Springer Verlag, Berlin. E. 0. McLean, Cornrnun. Soil Sci. Plan1 Anal.. 1976. 7. 6 19.

The Elemental Constituents of Soils

159

co-ordination with six OH, groups from each of which a hydrogen ion dissociates sequentially as the pH increases. The resulting hydroxo-A1 ions are adsorbed onto the cation-exchange system of the soil where they can obstruct the exchange of cations. Mobile A1 also reacts readily with soluble phosphates converting them to relatively insoluble and unavailable forms. The acidic nature of adsorbed and polymerized Al can lead to a misinterpretation of the true lime requirement of soil. In addition it can also affect the apparent requirement by its effect on the buffers used in the lime-requirement test. The level of exchangeable Al may therefore be an adequate index of lime requirement on highly weathered soils.5o9 During the podzolization process A1 and Fe move down the soil profile, being removed from the eluvial A horizons to be deposited in the illuvial horizons of accumulation, the B horizons. It has been commonly argued that the formation of podzols involves the transport of Al and Fe as organic c o r n p l e x e ~ but , ~ ~recent ~ ~ ~ evidence ~~ for the presence of imogolite and proto-imogolite allophane in podzol B horizons suggests that A1 moves in the form of a mobile ahminosilicate complex.512 The natural occurrence of allophane and imogolite in a soil environment has been recently reviewed.513The origin, composition, and structure of the oxides of aluminium, iron, and manganese in clays has been reviewed by Mackenzie et al.,514and the occurrence of amorphous materials of aluminium, iron, and silica in soils has been reviewed by Mitchell et al.515The formation of aluminium oxyhydroxides in soils has been recently reviewed by H s u . ~ ' ~ The Al-hydroxide layers in clay minerals and individual crystals, or in polymerized particles of gibbsite, contain positively charged adsorption sites which may play important roles in soils as points where anionic nutrient species (e.g., nitrate or borate) can be retained for later extraction by plant roots. Although the essentiality of Al for plant or animal growth has not been proved, A1 in soil is of great importance in the growth of plants. Soluble A1 is toxic to most plants and problems of toxicity can occur in acid soils. Some plant species accumulate Al, however, and Al succinate has been found to be exuded in the acid sap of some accumulator plants.s08It has also been found that bryophytes (mosses) contain a higher percentage of Al in their ashes than is common in the higher plant forms. These primitive plants play a significant role in weathering and in the development of soil on exposed rock surface^.^'^,^^'

Gallium.-Geochemistr. Although Ga is widespread in nature, its minerals are extremely rare and this element is generally associated with Al in the common minerals. The main feature of the distribution of G a in igneous rocks is its rather McKeague, G . J. Ross, and D. S. Gamble, in 'Quaternary Soils: 3rd Conf. on Quaternary Research'. ed. W. C. Mahaney, Geo. Abstracts Ltd., Norwich, 1978. p. 27. "' E. W. Russell, 'Soil Conditions and Plant Growth'. 10th Edn., Longman. London, 1973. 'I2 V . C. Farmer, J . D. Russell. and M. L. Berrow. J . Soil Sci.. 1980. 31. 673. ' I 3 K . Wada, in 'Minerals in Soil Environments', ed. J . B. Dixon, and S. B. Weed. Soil Sci. Soc. Am., Madison, Wisc., USA, 1977, p. 603. 'I4 R. C. Mackenzie, E. A. C. Follett, and R. Meldau. in 'The Electron optical Investigation of Clays', ed. J . A. Gard, Min. Soc. Monogr. No. 3, 197 1, p. 3 15. B. D. Mitchell. V. C. Farmer, and W. J . McHardy, A h . Agron., 1964, 16, 327. 5 ' 6 P. H. Hsu, in 'Minerals in Soil Environments', ed. J . B. Dixon and S. B. Weed. Soil Sci. SOC.Am., Madison, Wisc.. USA, 1977, p. 99. 5 ' 7 D. Jones, M. J. Wilson. and J . M. Tait, Lichenologisl. 1980, 12. 277.

s'" J . A.

En u iron men ta 1 Chemistry

160

uniform occurrence in most basic, intermediate, and granitic rocks. This is related to the role of feldspars as the main carriers of G a in these rocks. A\ :Ga ratios vary from 2500 to 50 000 in rocks with a mean of about 5000. The average concentration of G a in basalts is 17 mg kg-' and in granites to 18.5 mg kg-', these values being consistent with a figure of 18 mg kg-', which appears to be the best estimate of the crustal abundance of Ga.518Gallium levels are generally higher in freshwater than in marine argillaceous deposits. The low levels of G a in sandstones accord with the known depletion of the element in quartz. A crustal average content for gallium of 15 mg kg-' has been reported by Taylor.75

Weathering and Mobility. Gallium, like Al, is enriched in the products of intense weathering; it is more mobile than Al, however, and the ratio A1:Ga commonly increases in the residual materials in the weathering process. The element exists as Ga3+ in natural environments and the most important factor affecting its behaviour in the cycle of weathering and sedimentation is the low solubility of the hydroxide. Gallium is therefore not readily transported by most natural waters. Soil Contents. The mean gallium content in 1615 soils sampled world-wide was mg G a calculated (Table 28) to be 21.1 mg kg-' with a range of about 2-200 kg-'. This is in good agreement with the data of B ~ w e n , a' ~median value of 20 mg G a kg-' and a range of 1-200 mg G a kg-'. Gallium is present in most soils where it occurs mainly in aluminosilicates, isomorphously replacing A1 in the structure, and many soils thus have total A1:Ga ratios of -5000-10000. The general tendency for G a to be concentrated in residual materials, even though generally to a lesser degree than Al, is reflected in the fact that in many soil profiles the concentration of G a is positively correlated with the amount of clay. The usual trend in soil profiles is for a slight increase in G a content with increase in depth.518 There is little variation in the Ga content in soils from different climatic zones:

Table 28 Gallium soil contents (mg G a kg-') Soils Range 134 topsoils, Finland <3-60 18 soils, USA, 6 profiles 2-2 1 4 1 soils, Scotland, 8 profiles 8-70 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 8-2 1 15 soils, Wales, 5 profiles 20-50 108 soils, Ghana, 19 profiles 3-200 19 soils, Germany, 4 profiles 3-30 1 13 soils, Madagascar, 26 profiles 3-78 863 topsoils, USA 5-70 110 soils, Cameroon, 18 profiles 13-43 8 soils, Brazil 9-26 10 topsoils, Scotland 2 1-43 23 soils, Scotland, 4 profiles 10-25 16 15 Soils Overall Mean 2 1.1 mg G a kg-'

)I8

Mean 18.5 10.3 33.0 26.3 15.0 32.7 27.4 8.2 17.9 19.0 29.9 16.7 31.1 19.1

Ref: 382 228 3 4 92 299 6 8 22 77 23 70 69 122

K. H. Wedepohl (ed.), 'Handbook of Geochemistry', I1-3/3 1, Springer-Verlag, Berlin.

The Elemental Constituents of Soils

161

temperate regions 10-70 mg kg-I; arid regions 3-60 mg kg-I, mean 20-30 mg kg-l; tropical humid regions < 2.6-100 mg kg-', mean 20-30 mg kg-'.5'9 Gallium has no known function in plant or animal metabolism and is not essential for growth. In land plants there appears to be a tendency for the Al:Ga ratio to be somewhat lower than in soils from which the elements are derived.'75 In the upper horizons of profiles rich in organic matter increased extractability of G a has been found, the ratio of A1:Ga extracted being as low as 1500: 1, which suggests that there could be some preferential plant uptake of Ga.122

Indium.-Geochemistry. Indium exhibits a distinctly chalcophile behaviour in the minerals of the earth's crust and is present either as an inclusion, or occupying a lattice site in a host mineral. It concentrates in sulphide minerals, especially those having tetrahedral co-ordination about the principal metal, iron. In granites the In content decreases with decrease in total iron content. There is some concentration of In in early crystallizing rocks (basalts and gabbros) and also in the later stage rocks when sulphide formation takes place. The ranges and mean In contents of some common rock types are: ultrabasic rocks, 0.005-0.06 mg kg-I, 0.02 mg kg-'; basalts and gabbros, 0.015-0.32 mg kg-', 0.07 mg kg-'; granites, 0.01-2.0 mg kg-', 0.05 mg kg-'; shales, 0.03-0.23 mg kg-I, 0.06 mg kg-', and pelagic clays, (0.02-0.28 mg kg-I, 0.07 mg kg-'.520 The average In content of rocks is 0.056 mg kg-I and the contents in eighteen samples of sphqlerite and chalcopyrite ranged from 0.5-343 mg kg-I, mean 76 mg kg-'.521 The In content of 168 coal ashes from Bulgaria ranged from 0.005-0.57 mg kg-' and In is associated with both the organic and the inorganic matter in Weathering and Mobility. During weathering, In dissolves as In3+ and disperses following Fe3+ and Mn4+ ions.523It precipitates under conditions that favour the formation of hydrous and is associated with iron and manganese in some hydrolysate sediments.524

Soil Contents. There is little published information on indium in soils. Seven soils from Brazil have In contents ranging from 0.07-0.5 mg kg-I, mean 0.15 mg kg-1,70 whereas eight soils from Ontario, Canada, have contents ranging from 0.56-2.95 mg kg-', mean 1.71 mg kg-1.525It is suggested that the total indium content of soils might fall within the range 0.7-3.0 mg kg-' with a median value of 1.0 mg k-'.74 These values, based on limited evidence, may well be high. Indium is toxic to rats74 and can also be toxic to plants,526the effects being similar to those caused by an excess of aluminium. The plant uptake of trivalent cations including indium has been studied by Dekock and H. Aubert and M. Pinta, 'Trace Elements in Soils', Elsevier, Amsterdam, 1977, 395 pp. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-4/49, Springer-Verlag, Berlin. 5 2 1 G. M. Eskenazy and E. Mincheva, Analyst (London), 1978, 1 1, 1 179. 5 2 2 G. M. Eskenazy, Geochim. Cosmochim. Acta, 1980,44, 1023. 5 2 3 D. M. Shaw, Geochim. Cosmochim. Acta, 1952,2, 185. 524 D. M. Shaw, Phys. Chem. Earth, 1957,2, 164. "' A. Chattopadhyay and R. E. Jervis, Anal. Chem., 1974,46, 1630. 526 G. F. Liebig, A. P. Vanselow, and H. D. Chapman, Soil Sci., 1943, 56, 173. J 2 7 P. C. Dekock and R. L. Mitchell, Soil Sci., 1957, 84, 55. 519

J20

Environmental Chemistry

162

Thallium.-Geochemistry. Thallium minerals are of very rare occurrence in nature and TI usually occurs in rock-forming minerals by isomorphous replacement, particularly in those rich in potassium, such as biotite and potassium feldspars. The T1 contents of rocks generally increase from basic to acidic and the following ranges have been found in various rock types: ultrabasic, 0 . 0 7 - 0 . 3 0 mg kg-I; basic, mg kg-'; granitic-rhyolitic rocks, 0.05-0.7 mg kg-'; intermediate, 0.15-1.4 0.6-3.5 mg kg-I; sedimentary, 0.1-2.0 mg kg-'.52s Argillaceous rocks and coal may be relatively rich in TI, containing up to 2.2 or 3.0 mg kg-I. Secondary minerals rich in T1 are jarosite and manganese oxides. Thallium seems to precipitate together with Mn, probably as T1203in strong oxidizing environments. The potassium manganese oxide, cryptomelane, identified in a manganese deposit in Banffshire, contains 170 mg T10, kg-1.529 The crustal abundance of TI in the rocks of the earths crust is 0.45 mg kg-1,75 whereas the mean content of 68 rocks (mostly basic) analysed by De Albuquerque et ~ 2 1 . ~is~0.19 ' mg kg-'. Weathering and Mobility. During erosion TI goes into solution as the univalent cation but is removed thereafter by adsorption on clays.53' Clay separated from the Boshan adamellite in Cornwall contained the same amount of TI as the unaltered rock,91 although the weathering of a granodiorite, an andesite, and a shale showed an enrichment of TI in their respective weathering products in the order weathered mantle > clay > loam and silt.532It appears therefore that T1 is largely retained in the products of weathering and may well show some enrichment in soils. Decaying organic matter may well concentrate TI as it has been shown to be enriched in sedimentary rocks containing carbonaceous matter.531 Soil Contents. Information on the TI content of soils is limited. A median value of 0.2 mg T1 kg-' and a range of 0.1-0.8 mg T1 kg-' has been quoted for soils by B ~ w e n .The ~ ~ T1 contents of ten Scottish topsoils on a wide range of parent materials69 has a mean value of 0.3 1 mg kg-' and a range of 0.11-0.76 mg kg-I, but the mean content of 4 Ontario525 soils is 0.19 mg kg-I with a range of 0.17-0.22 mg kg-I. A mean soil content of 5 mg T1 kg-' has, however, been reported.73In the absence of comprehensive information the mean value can only be tentatively assessed therefore at about 0.25 mg TI kg-I.

13 Carbon, Silicon, Germanium, Tin, and Lead Carbon.-Geochemistry. In magmatic rocks carbon occurs in carbonates, in carbides, in elementary form as graphite, and in gaseous or fluid inclusions. Carbon is not likely to replace Si4+in crystal lattices. A calculated mean value for carbon in granites is 160 mg C kg-' (= 600 mg kg-' as carbonate). Other acid, intermediate, gabbroic, and ultrabasic rocks have similar carbon contents. Calcite is one of the

'" K. H. Wedepohl (ed.), 'Handbook of Geochemistry', I1-5/8 1, Springer-Verlag, Berlin. '29

M. J. Wilson, M. L. Berrow. and W. J . McHardy, Mineral. Mag., 1970. 37, 618.

'" C. A. R. De Albuquerque, J . R. Muysson, and D. M . Shaw. Chem. Gcol., 1972, 10.41. 53' 512

D. M. Shaw. Geochim. Cosrnochim. A c ~ a 1952. . 2, 118. M. S. Kurbanayev, Geochern. In,.. 1966,568.

The Elemental Constituents of Soils

163

most common gangue minerals formed from ore-forming fluids, while carbonatites are carbonate-rich rocks crystallized from a carbonate magma. Sediments usually contain twenty times more carbon than magmatic rocks, but metamorphic rocks, even though they frequently contain graphite, have carbon contents similar to those of igneous rocks. Biologically produced organic compounds also occur in rocks, particularly sediments. Carbon is present in these organic compounds, which include proteins, carbohydrates, and fats, and in organic accumulations such as coal and petroleum, which are fossilized vegetable or animal matter.533A crustal average for carbon of 200 mg kg-’ has been reported by Taylor,75with basalt and granite averages of 100 and 300 mg kg-’, respectively.

Weathering and Mobility. During volcanic activity, in the oxidative decomposition of organic matter, and during plant growth, carbon is released into the atmosphere as CO,. Its content in the atmosphere is 0.03 vol.% and it is essential to photosynthesis and plant growth, The level of CO, in the atmosphere is fairly constant because it is in equilibrium with that dissolved in sea water. Many reactions in natural waters are thus controlled by the CO, content in the atmosphere. Carbonic acid takes part in the weathering of rock and soil minerals. The bicarbonate ion HCO; forms about 50% of the total amount of dissolved material in river water and is a major dissolved component of rainwater. Organic acids derived from plant residues or produced by soil bacteria also take part in the weathering of rocks and soil minerals.534 Soil Contents. In soils, carbon is present as inorganic carbonates, as organic matter derived from plant and animal residues and as carbon dioxide in the soil atmosphere or dissolved in the soil solution. Calcite and dolomite constitute most of the soil carbonate minerals. These are either inherited from the original soil parent materials or formed as a result of pedogenic processes. The behaviour of calcium and magnesium carbonates in soils has been discussed by Doner and Lynn.53sCarbon dioxide from the atmosphere is converted by plants into various organic substances that are added to the soil when plants decay or when animal wastes are returned to the soil. Carbon is thus strongly enriched in soils relative to rocks. Much of the carbon present in soils is in organic form as carbohydrates, proteins, fats, and waxes or other higher-molecular weight complex molecules that comprise soil humic substances. Organic-matter transformations and the cycle of carbon in soils has been discussed by Stevenson,536 and the chemistry of soil organic colloids by Hayes and Swift.537Where the decomposition of plant residues is inhibited by low temperature, poor drainage, etc., plant residues can accumulate to considerable depth as peat which contains very little mineral matter. Soil organic matter has many important properties including the provision of nutrients such as K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11- 1/6, Springer-Verlag, Berlin. R. B. Duff, D. M. Webley, and R. 0. Scott, Soil Sci., 1963, 95, 105. J35 H. E. Doner and W. C. Lynn, in ‘Minerals in Soil Environments’, ed. J. B. Dixon and S. B. Weed, Soil Sci. SOC.Am. Madison, Wisc, USA, 1977, p. 75. 536 1. L. Stevenson, in ‘Chemistry of the Soil’, ed. F. E. Bear, Reinhold, NY, 1964, p. 242. 537 M. H. B. Hayes and R. S. Swift, in ‘The Chemistry of Soil Constituents’, ed. D. J. Greenland and M. H. B. Hayes, 1 9 7 8 , ~ 179. . J33

534

I64

En vironmen ta 1 Chemistry

N, P, and S, the control of the supply of other nutrients such as Cu, the improvement of soil structure, and the formation of organic growth substances. The role of organic matter in soil fertility has been recently reviewed by and the turnover of soil organic matter in some of the Rothamsted classical long-term experiments investigated by Jenkinson and R a ~ n e r A. ~model ~ ~ of the transformation of organic matter in soil indicated that a portion, the chemically stabilized organic matter, was extremely persistent and had a half-life of 1980 years. A recent estimate of the amount of carbon in soil organic matter throughout the world has been made by Bohn5,’ and amounts to nearly 30 x lo1, kg. Soil organic matter can become intimately mixed with the mineral fraction and the reactions of minerals with soil humus substances has been reviewed by Schnitzer and K ~ d a m a . The ~ ~ ’cycle of carbon in the environment has been discussed by Bowen’, who reports that the mean organic carbon content of soils ranges between 0.7 and 50%, with a median content of 2.0%. Silicon.-Geochemistry. The geochemistry of silicon in the earth’s crust is essentially the geochemistry of silica, SO,, and the common silicates. Silicon in its combined form, as the tetrahedral SiO, group, is a major constituent of the majority of the common rock-forming minerals. Most of the silicon in the earth’s crust occurs in plagioclase, the most abundant mineral, while much less occurs as quartz. Silicon, expressed as SiO,, usually ranges from -35--85% in igneous rocks. There is an increase in silicon content from the ultrabasic igneous rocks (peridotite etc.) through the sequence of rocks formed during magma crystallization to the acid igneous rocks (granites etc.). Metamorphic rocks such as gneisses, schists, and slates contain 60-70% SiO,, whereas amphibolites and eclogites contain 45-50% SO,. Sedimentary rocks also vary widely in their silicon contents. Most detrital sandstones and conglomerates contain 65-95% SO,, whereas arkoses and greywackes contain 40-85% SiO,. Some chemical sediments such as cherts, siliceous earths, and sinters may be close to 100% SiO, but can also be as low as 64% SiO,, while limestones contain varying amounts of SiO,. Various estimates of the abundance of silicon, expressed as silica, in the earth’s crust, are close to 60 & 3% Si02.542The structure and composition of the ortho-, chain, sheet, and framework silicates in rocks have been fully documented by Deer et a1.543 Weathering and Mobility. Silicate minerals can be divided into three broad groups on the basis of their behaviour during weathering: (a) those that are easily weathered such as the relatively simple-structured olivine and pyroxenes, (b) those that are moderately resistant to weathering such as the more complex layer and framework silicates including the micas and feldspars, and (c) those that are essentially resistant, typified by quartz. The three silicates that persist as detritus in greatest abundance are quartz, feldspar, and mica. As silicates weather and E. W. Russell, Philos. Trans. R. SOC. London. Ser. B, 1977, 281, 209. D. S. Jenkinson and J. H. Rayner, Soil Sci., 1977, 123, 298. 540 H. L. Bohn. J. Soil Sci. SOC. Am., 1976, 40,468. M. Schnitzer and H . Kodarna, in ‘Minerals in Soil Environments’, ed. J. B. Dixon and S. B. Weed, Soil Sci. SOC.Am.. Madison, Wisc., USA, 1977, p. 741. 342 K . H. Wedepohl (ed.). ‘Handbook of Geochemistry’, 11-2/14, Springer-Verlag, Berlin. 5 4 3 W. A. Deer, R. A. Howie. and J. Zussrnan, ‘Rock-forming Minerals’, Longmans, 1962, Vol. 1-4. ’38 ‘j9

165

The Elemental Constituents of Soils

hydrolyse in water they release silica into solution in concentrations in the range 10-30 mg kg at normal temperatures. Analyses of river and sea waters have shown that monomeric silicic acid, H,SiO, or Si(OH),, is the dominant species present, the median concentrations of SiO, in streams world-wide being approximately 13 mg kg-I. Most natural waters are in the pH range 5-9, but in alkaline solutions, above pH 9, the ionization of the silicic acid becomes appreciable and polymerization of charged and uncharged species begins leading to the eventual synthesis of clay minerals. At normal temperatures the weathering of silicates also produces the secondary oxides and clay minerals that comprise the clay fraction of soils.542

Soil Contents. The silicon content, expressed as SiO,, makes up the bulk of those mineral soils that have not been greatly modified from the rocks from which they were derived. The SiO, content of many soils ranges from 50-70%, which approximates to the crustal average of 60.3% SiO, (28.15% Si) reported by Taylor.75In organic soils and in the A horizons of soil profiles the silicon content is decreased by dilution with organic matter. Many soils in the humid tropics which have been subjected to intensive weathering and leaching are depleted of silicon. In addition to quartz, feldspars, and micas in soils, other common detrital silicates include the clay minerals and a variety of accessory heavy minerals. The occurrence of silica in soils, largely in the forms of quartz and less commonly cristobalite, Quartz, cristobalite, and tridymite, and opal, has been reviewed by Wilding et al.544 tridymite are largely inherited from the parent rock, whereas most opal found in soils is of biogenic origin.545Biogenic opal is a minor ubiquitous constituent of most soils commonly ranging in amount from <0.1-3% on a total soil basis. The formation and occurrence of the aluminosilicate clay minerals, the micas, vermiculites, montmorillonite, chlorite, kaolinite, and other soil minerals have been comprehensively discussed by many author^."^^ Th e composition and identification of accessory heavy minerals in soils has been reviewed by A few groups of invertebrate aquatic animals secrete silica as skeletal material, but most animals excrete silica rather than incorporate it into body tissues. Silicon has, however, been proved essential to the growth and skeletal development of rats and Plants typically contain silica and the opaline form is found in the tissue of many vascular plants. Opal phytoliths, very small pure amorphous silica grains of many and varied shapes and sizes (usually ( 5 pm), are formed by many plants. Silicification in cellular tissues and walls occurs in the aerial tissues of most plants and in the rhizomes of certain grasses. Monocotyledons contain 10 to 20 times the silica contents of dicotyledons, and grasses commonly contain 3-5% SiO, on a dry-weight The rice plant readily takes up silicon and nutritional 25935467547

L. P. Wilding, N. E. Smeck, and L. R. Drees, in ‘Minerals in Soils Environments’, ed. J. B. Dixon and S. B. Weed, Soil Sci. SOC. Am. Madison, Wisc., USA, 1977, p. 471. 545 L. H. P. Jones and K. A. Handreck.Adu. Agron., 1967, 19, 107. 546 J . E. Gieseking, ‘Soil Components, Vol. 2. Inorganic Components’, Springer-Verlag, Berlin, 1975, 684 PP. 547 G. Brown, A. C. D. Newman, J. H . Rayner, and A. H. Weir, in ‘The Chemistry of Soil Constituents’, ed. D. J . Greenland and M. H. B. Hayes, John Wiley and Sons, 1978, p. 29. 548 W. A. Mitchell, in ‘Soil Components, Vol. 2, Inorganic Components’, ed. J . E. Gieseking, Springer-Verlag, Berlin, 1975, p. 449. 544

166

Environmental Chemistry

studies have been carried out in attempts to establish the essentiality of silicon for this crop.549

Germanium.-Geochemistry. The germanium contents of most silicate rocks, igneous as well as sedimentary and metamorphic, vary from about 0.5-3 mg kg-' and the contents of the rock-forming minerals are of the same order of magnitude. There are no significant differences between the germanium contents of basic and granitic rocks, but greisen, pegmatite, and sulphide formations are often rich in germanium. The correlation of fluorine and germanium concentrations in greisenized rocks indicates that fluorine is important in germanium transport. The principal host mineral for germanium in pegmatites is topaz, while sphalerite may contain up to 1000 mg G e kg-I. Low germanium contents are found in sandy sediments and sandstones (mean 1.2 mg kg-I), and carbonate rocks (mean about 0.2 mg kg-I), but relatively high contents (mean 2 mg kg-') are found in argillaceous sediments and clays. The average abundance of germanium in metamorphic rocks is close to 1.7 mg kg-'.550 The average content of the rocks of the earths crust has been reported to be 1.5 mg kg-1.75 Weathering and Mobility. Germanium in natural waters is always present in the tetravalent state and most is present in true solution. Sea and river waters are, however, very low in germanium with contents of about 0.05 pg kg-'. During weathering germanium is partly removed from rocks, but the bulk remains in the solid products of weathering, most likely in clay minerals. It is structurally incorporated into the clay minerals of deep sea sediments. No accumulation of germanium in the manganese nodules of ocean floors has been reported and it is not concentrated in bauxites (range 1-3.6 mg k-I, mean 2.4 mg kg-I) as compared with other The accumulation of germanium in coal, humus, peat, and even petroleum is well known and the burning of coal and oil releases considerable quantities.68Coal ashes can contain several per cent germanium but it is irregularly distributed in coal seams. It is predominantly bound to the organic matter of coals and is probably of secondary origin as a result of infiltration of water during or after coalification, underground water being generally richer in germanium than surface waters.550 Soil Contents. Data on the germanium content of soils is very limited. A value of about 1 mg kg-I has been reported as the germanium content of soils of the USSR,68whereas values up to 10 mg kg-I have been reported for some surface soils in Scotland and up to about 50 mg kg-' in some Czechoslovakian soils.93A range of 0.1-50 mg G e kg-', with a median content of 1.0 mg Ge kg-', has been reported by B ~ w e nMany . ~ ~ soils in arid and tropical regions contain less than 3 mg G e kg-' but some soils from Madagascar contained up to 17 mg Ge kg-'.5'9 Germanium accumulates in humus soils and it has been suggested that it is strongly adsorbed by the OH-groups of humic This is consistent with the detection of germanium in organic horizons of some Scottish podz01s.~Using spark source S. Mitsui and H. Takatoh, Soil Sci.Plant Nutr., 1963, 9, 49. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-3/32, Springer-Verlag, Berlin. 5 5 ' S . A. Gordon and A. G . Motina. Nauchn. Tr. Mosk. Corn. Inst., 1959, 27. 51. 549

"O

The Elemental Constituents of Soils

167

mass spectrometry, the germanium content of ten typical Scottish topsoils has been determined and found to range between 1.2 and 9.9 mg kg--', mean 3.1 mg kg-'.6' Germanium does not appear to be essential to the growth of plants or animals, but it has been shown to be toxic to rice plants in soils to which 10 mg kg-' had been added. The rice shoots accumulated up to 2000 mg Ge kg-I with growth reductions of 20-30%.552 Although Ge. like Si, accumulates in rice plants it has been found that the physiological actions of the two elements are quite different. Unlike Si, the action of Ge in rice is very toxic and causes the appearance of necrotic spots on leaf blades.s53Most plant ashes, however, normally contain less than 10 mg Ge kg - I . Germanates have a low order of toxicity in mice and rats and dietary germanium, although well adsorbed, is excreted largely via the kidneys in man.96

Tin,-Geochemistry. Tin is rare in early magmatic sulphides, being enriched particularly in pneumatolytic and hydrothermal formations. In rocks formed at high temperatures it occurs almost exclusively in oxygen-bearing compounds, often as cassiterite (SnOh, the most important ore of tin and the most common of all tin minerals. Cassiterite occurs in veins or metasomatic deposits closely associated with highly siliceous igneous rocks and is highly resistant to weathering. Tin also occurs in 'dark minerals' such as sphene, hornblende, and biotite in igneous rocks where it replaces titanium and trivalent iron. The average tin contents of different types of rock are; silicic rocks 3.5, intermediate rocks 1.4, basic rocks 1.0, ultrabasic rocks 0.45, and shales and clays around 5 mg kg-1.554A value of 2 mg kg-' has been reported as the crustal average for tin.75 Weathering and Mobility. Minerals containing tin, particularly cassiterite, are strongly resistant to weathering. Some tin is dissolved in natural waters, however, and its fate is determined by several factors, including oxidation-reduction conditions. Stannic tin is probably the only stable ionic species in the weathering cycle because divalent tin is readily oxidized. Tin becomes enriched in aluminiumrich resistates such as bauxites but its mobility is very low and about the same as that of Ba, Ti, and Zr.5s4 Soil Contents. The overall mean Sn content of 6 18 soil samples from various parts of the world, reported in Table 29, is 5.8 mg kg-I with a range of 0.1-40 mg kg-'. A median value for Sn soil contents of 4 mg kg and a range of 1-200 mg kg-' have been r e p ~ r t e d , ' ~although an earlier suggests that normal soils probably contain up to 10 mg Sn kg-I. Soils from arid and tropical humid regions contain from < 1-60 mg Sn kg-' and tin was found to accumulate in clay and organic matter.s19High Sn levels have been found in soils near tin mineralized areas in south-west England with levels of (10-250 mg kg-'. mean 70 mg kg-1.555 Under Scottish conditions, enrichment of Ag, Cu, Mo, Pb, and Sn has been found in j5'

K. Tensho and K . L. Yeh, Soil Sci.Plant Nutr., 1973, 18, 173.

'" H. Matsurnoto, S. Syo. and E. Takahashi, Soil Sci. Plant Nutr.. 1975, 21, 273. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-4/50.Springer Verlag. Berlin. A. P. Millman. Geochim. Cosmochim. Acta, 1957. 12, 85.

jS4

555

En u iron men ta 1 Chemistry

168

Table 29 Tin soil contents (mg Sn kg-') Soils Range 20 soils, England, 4 profiles 4-40 10-30 134 topsoils, Finland 2-19 18 soils, USA, 6 profiles 1-1 1 10 topsoils, New Jersey, USA 1-12 360 soils, China, 11 1 profiles 58 soils, New Brunswick, 13 profiles 0.1-11 8 soils, Ontario, Canada 10.1-14.2 2.1-8.4 10 topsoils, Scotland Overall Mean 5.8 mg Sn kg-' 6 18 Soils

Mean 16.4 4.3 7.9 3.0 6.0 3.4 12.7 3.8

Ref: a 382 228 b C

25 2 525 69

a J. R. Butler, J . Soil Sci., 1954, 5, 156; A. L. Prince, Soil Sci., 1957, 84, 413; ' C. L. Fang, T. C. Sung, and Yeh Bing, Acta Pedologica Sinica, 1963, 11, 130

uncultivated organic-rich surface horizons of profiles.' This may well be due to the strong association of these metals with soil organic matter. Unlike lead, tin is generally a biologically innocuous element and plants absorb it only to a very slight extent,556although in some plant species levels as high as 4 6 mg kg-' in the ash have been reported.554Pasture herbage in Scotland contains 0 . 3 - 0 . 4 mg Sn kg-' (dry-weight Tin has now been shown to be an essential nutrient for the growth of rats. Because of its poor absorption 96 humans and experimental animals are extremely tolerant of fruit juices and other food contaminated with tin from containers.

Lead.-Geochemistry. Because of its similarity in ionic size to potassium, Pb2+ replaces potassium in silicates, and particularly in potassium feldspars and biotite. There is generally an increase in lead content in the sequence from ultrabasic to granitic rocks. The lead content of granitic intrusives is mainly controlled by their potassium feldspar content. The arithmetic mean calculated for lead in 1220 granitic rocks was found to be 2 3 mg kg-1.558In sedimentary rocks, sands are generally poorer in lead than shales. The mean lead content of 924 sands and sandstones was found to be 10 mg kg-', of 363 clays and shales 23.3 mg kg-', and of 779 black shales 23.8 mg kg-I. The abundance of lead in metamorphic rock types is generally less than in granitic rocks, the average of 3846 gneisses and schists being 17 mg kg-'.558 A crustal abundance of 12.5 mg kgg' for lead has been reported by Taylor.75 Weathering and Mobility. In igneous and metamorphic rocks lead occurs primarily in potassium feldspars and micas which are moderately resistant to weathering.' As a result the rate of mobilization of lead is low. During the chemical weathering of granitic rocks biotite is probably the first lead-containing mineral to break down and, although lead occurs naturally in both the divalent and tetravalent forms, the former predominates. Most salts of Pb2+with naturally occurring anions are only slightly soluble. In addition, adsorption of mobilized lead on clay minerals and organic substances will limit freshwater lead concentrations. The average lead m E. F. Wallihan, in 'Diagnostic Criteria for Plants and Soils'. ed. H. D. Chapman, Univ. of California,

Div. Agric. Sci., 1966, p. 476. R. L. Mitchell, Research, 1948, 1, 159. J J 8 K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/82, Springer-Verlag, Berlin.

ss7

The Elemental Constituents of Soils

169

concentration in continental surface waters from remote areas largely free from pollution is 3 ,ug kg-1.55RThe solubility and occurrence of lead in surface water has been reviewed by Hem559and a review of lead in the hydrosphere prepared by

Soil Contents. The world-wide average P b content of 4970 soils calculated in Table

< 1-888 mg kg-’. The lead content of immature soils tends to be correlated directly with its concentration in the parent material. For

30 is 29.2 mg kg-’ with a range of

Table 30 Lead soil contents (mg P b kg-’)

Soils Range 2 1 soils, England, 4 profiles 15-160 44 soils, E. Canada, 8 profiles 6-108 134 topsoils, Finland < 10-600 6-155 18 soils, USA, 6 profiles 14-96 10 topsoils, USA 4 1 soils, Scotland, 8 profiles 10-80 19 soils, USA, 4 profiles < 10-24 15 soils, Wales, 5 profiles 8-200 360 soils, China, 11 1 profiles < 1-49 113 soils, Madagascar, 26 profiles 8-175 26 1 soils, New Brunswick, 56 profiles <5-420 110 soils, Cameroon, 18 profiles 12.2-1 27 32 soils, Ontario 8.2-4 5.0 20 topsoils, England 23.0-53.0 44 1 topsoils, British Columbia 39 topsoils, Canada 7-43 37 topsoils, England 48-307 296 topsoils, Ontario 1.5-888 46 soils, Poland, 9 profiles 3.3-102 964 topsoils, USA < 10-700 2.2-364 36 1 topsoils, Sweden 5 1 topsoils, Denmark 500 topsoils, Wales < 1-356 208 soils, Scotland, 4 1 profiles <3-400 752 topsoils, England and Wales 5- 1200 23 soils, Scotland, 4 profiles 6-20 12 1 soils, Wales 12 topsoils, S.E. USA 7-5 7 173 soils, Canada, 53 profiles 5-50 4970 Soils Overall Mean 29.2 mg Pb kg-’

Mean 47.8 2 1.0 135 75.8 44.1 24.1 13.4 96.9 26 32 26.5 28.3 23.0 41.2 10.4 20.7 114 45.8 20.8 20.0 15.9 24.1 39 30.0 (median 42) 6.7 41 29.2 20

R eJ: a b 382 228 C

3

4 5 d 22 25 2 23 525 e

f

415 193 g h

1

.i

k I

56 1 299* 122 rn

805

n

* Not included in Mean J. R. Butler, J . Soil Sci., 1954, 5, 156; J. R. Wright, R. Levick, and H. J. Atkinson, Soil Sci. Soc. Am. Proc. 1955, 19, 340;‘ A . L. Prince, Soil Sci., 1957, 84, 413;d C . L. Fang, T. C. Sung, and Yeh Bing, Acfa Pedologica Sinica, 1963, 3. 117;‘C. Williams, J. Agric. Sci. Carnb., 1974,82, 189;’M. K. John. Symp. Proc. Int. Conf. Heavy Metals in the Environment, Toronto, Canada, 1975, 365; R. Frank, K. Ishida, and P. Suda, Can. J . Soil Sci., 1976. 56. 181; Ir A. Sapek and P. Sklodowski, Rocz. Glebozn., 1976,27,137;* R.R.Tidball, US Geol. Suru. ProJ Pap., 1976,957,43;’A.Andersson,Swedish, J . Agric. Res., 1977, 7, 7 ; J. C . Tjell and M. F. Hovmand. Acfa Agric. Scund.. 1978, 28, 81; ‘ C . Williams, Environ. Pollul., 1978, 15. 23; “ R . I. Bradley, Geodrrrna, 1980, 24, 17; J. A. McKeague and M. S. Wolynetz, ibid.. p. 299

s5y s60

J. D. Hem, J. Am. Water Works. Assoc., 1973.65.562. T.J. Chow, Pure Appl. Chem., 1978,50,395.

170

Environmental Chern istry

example, higher concentrations of lead have been found in soils derived from granite compared with a range of other parent material^.^,^^' Many of the averages reported for lead in soils are similar to the average concentration in the lithosphere of 16 mg kg-' 115 and range between values of 10 and 40 mg kg-'. In most soils from non-mineralized areas lead contents range from 2-200 mg kg-1,93but the lead content of the soils of the Russian plain ranges from 3.7-43.3 mg kg-', mean 12 mg kg-1.68 A range of 2-300 mg Pb k g ' , median 35 mg Pb kg-', has been reported by B ~ w e nand ~ ~an average lead content of 15-20 mg kg-' in soils world-wide by Aubert and P i r ~ t a . ~ ' ~ Many w ~ r k e r ~ ' , ~have ~ , established' ~ ~ . ~ ~ that ~ - the ~ ~highest ~ concentrations of lead in soil profiles generally occur in the surface horizons, probably as a result of enrichment by deposition from the atmosphere, by biological cycling, or by both processes. A highly significant correlation between total lead content and loss-on-ignition was found in 208 samples from 41 soil profiles in S.W. Scotland,561 while strong retention of lead, together with Hg, Bi, and TI in organic surface layers of soils in European forest ecosystems has been reported by Heinrichs and

ma ye^.^^^ In subsoil horizons, lead released by pedological weathering is adsorbed by clay minerals, secondary oxides, and organic matter. Enrichment of lead in the clay fraction of soils derived from basalt has been reported by Short9* and in soils derived from g r a ~ ~ i t e .The ~ ' . adsorption ~~ of lead and other heavy metals on oxides of manganese and iron has been studied by M ~ K e n z i eand , ~ ~the ~ fixation of lead by humic acids in soils has also been A review covering most of the literature pertinent to the behaviour of lead in soils and plants has been prepared by Zimdahl and Arvik.j70 The lead content of soils can be greatly affected by contamination from various sources including outwash from dumps near old metal-mining areas, by aerial deposition near ore-crushing plants, by the dumping of paints, old motor-car batteries, e t ~ . , ' ~and by the use of lead arsenate as an insecticide. Much work has been done world-wide on the effects of automobile exhausts on the lead contents of soils and plants particularly along major highways. These have generally supported the findings of Page et al., 5 7 1 who showed that the amounts of lead in and on the surface of crops grown close to freeways in Southern California were influenced by ( a ) distance from the highway, (b) extent of surface exposed, (c) nature of the collecting surface, ( d ) duration of exposure, (e) motor vehicle traffic density, and (f)direction of the prevailing winds. Contamination from this source can considerably increase the levels of lead in surface soils; up to 403 mg kg-I in

G. A. Reaves and M. L. Berrow, J . Sci. Food Agric., 1979, 30. I. V. M. Goldschmidt, J. Chem. SOC.,1937, Part 1, 655. 5 h 3 A. S. Dolobovskaya, Sou. Soil Sci., 1975, (7), 189. J64 H. Heinrichs and R. Mayer, J. Environ. Qual., 1977,6, 402. 565 R. M. McKenzie, Aust. J. Soil Res., 1980, 18, 6 1. 566 H. Van Dijk, Geoderma., 1971, 5, 5 3 . 567 E. E. Hildebrand and W . E. Blum, Naturwissenschafen, 1974,61, 128. E. E. Hildebrand and W. E. Blum, Z. P'anzenernaehr. Bodenkde., 1975, 138, 279. F. J. Stevenson, Soil Sci., 1977, 123, 10. 570 R. L. Zimdahl and J. M. Arvik, Crit. Reo. Environ. Contr. 1973. 3, 213. A. L. Page, T. S. Ganje. and M . S. Joshi, Hilgardia, 1971. 41, I.

"I

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The Elemental Constituents ojsoils

171

Maryland, USA;572540 mg kg-' in USA;573543 mg kg-' in Virginia, USA;5741100 mg kg.-';575 3064 mg kg-1576in some New Zealand soils, although other authors have reported lower values. These include maximum lead values of 78 mg kg-' in Germany,577130 mg kg-I in England,57xand 43 mg kg-I in Italy"' presumably due to lower traffic densities. Little elevation of lead levels in subsoils along major roads has been found, h o w e ~ e r , ~ and ~ ~ ,elevated ~~' total levels in topsoils are often confined to areas within 100 m of the roadway.58' The average lead content of roadside dusts in Christchurch, New Zealand was 1790 mg kg-l, similar to levels found in cities in England and the USA. The lead contents were found to be related to traffic density.582The principal constituent of the soil derived from automotive sources appears to be lead s ~ l p h a t e . ~An ~ ~ assessment ?~*~ of the health hazards arising from lead in urban dust has been made by Duggan (see ref. 830). Mining activities can produce wastes high in lead and other heavy metals. Dusts from waste dumps can contaminate soils, 585-5y0 increasing soil levels to the order of 1% in some cases. Soils containing up to 2.5%, and vegetation up to 400 mg Pb kg-', have been reported from five sites in Norway where natural lead poisoning of soils and vegetation has been produced by underlying galena Soils near lead-zinc smelters can accumulate large amounts of lead from atmospheric deposition. Contamination declines with distance from the smelters, but can be detected 40-65 km from the source depending upon wind direction.592 In the plough layer less than 500 m from a smelter in south Finland an average soil content of 378 mg 1-' was found, some 70 times that found in normal field soils in Finland.593Other soils near smelters have been found to contain up to 1930 mg Pb

T. J. Chow, Nature, (London), 1970, 225, 295. J. V. Langerwerff and W. A. Specht, Enciron. Sci. Technol., 1970,4. 583. '14 H. D. Quarles 111, R. B. Hanawelt, and W. E. Odum,J. Appl. Ecol., 1974, 11, 937. '15 N. I. Ward, E. Roberts, and R. R. Brooks, N.Z. J . Sci., 1977,20,407. ' 1 6 N. I. Ward. R. R. Brooks, E. Roberts, andlC. R. Boswell, Environ. Sci. Technol., 1977. 11. 917. G . Sommer, A. Rosopulo, and J . Klee. Z . PJlanzenernuehr. Bodenkde.. 197 1. 130, 193. B. E. Davies and P. L. Holmes, J . Agric. Sci., 1972, 79,479. 'lY C. Sapetti and E. Arduino, Agrochirnicu, 1973, No. 6, 540. "OJ. J. Connor, J. A. Erdman, J . D. Sims, and R. J . Ebens, in 'Trace Substances in Environmental Health', ed. D. D. Hemphill, Univ. of Missouri, Columbia, 1970, Vol. 4, p. 26. H. L. Motto, R. H. Daines, D. M. Chilko, and C. K. Motto, Entiiron. Sci. Technol., 1970. 4, 23 1. 5 8 2 J . P. Day, N.Z. J. Sci., 1977, 20, 395. 5 8 3 K . Olson and R. K. Skogerboe. Enuiron. Sci. Techno!., 1975,9, 227. 584 R. M. Harrison and D. P. H. Laxen. Chern. Br., 1980, 16. 3 16. €3. J . Alloway and B. E. Davies, Geoderma, 1971.5. 197. 5 8 6 B. E. Davies, Oikos, 1971, 22, 366. 5 x 7 D. D. Hemphill, C. J. Marienfeld, R. S. Reddy, and J. 0. Pierce, Arch. Enziiron. Health, 1974. 28, 190. 588 N . E. Ward, R. R. Brooks, and R. D. Reeves, N . Z . J . Sci., 1976, 19, 81. P. Colbourn and 1. Thornton, J . Soil Sci., 1978, 29, 5 13. 590 A. Oxbow and J. Moffat. Plan( Soil, 1979, 52, 127. 59' J . L i g and B. Bolviken, Nor. Geol. Under. Publ., 1974, No. 304, 73. ' 9 2 B. Cartwright, R. H. Merry, and K. G. Tiller, Aust. J . Soil Res., 1977, 15, 69. 593 R. Ervio and E. Lakanen, A n n . Agric. Fenrt., 1973, 12, 200.

572

'13

'" "'

172

Environmental Chemistry

kg-' in south east 9000 mg Pb kg-' in Yugoslavia,5951173 mg Pb kg-' in North Humberside, and 12.6% in New Zealand.575 Lead tends to become firmly fixed in topsoils particularly those rich in organic matter, presumably because the Pb2+ion has a high stability constant with organic chelating groups.2x4The inorganic salts of lead are generally highly insoluble and lead can therefore be precipitated as sulphate, carbonate, or phosphate in soils. After the closure of a smelter in South Wales the level of lead extractable by acetic acid was found to decrease from 300 to 200 mg kg ' over a period of 16 months, presumably as the exchangeable lead became fixed in less extractable forms.597The leachability of lead from an organic forest soil has been studied by Tyler,5Y8who used a contaminated soil and artificial rainwater, acidified to a pH of 4.2, to predict that it would take more than 200 years to decrease the total lead content by 10% at normal rainfall rates. The concentrations of Pb and Zn in organic horizons of soils in a remote forested areas of Northern New England were found to be high and comparable with those for the margins of busy roads.59YIt was suggested that deposition rates are highest in subalpine forests where there is a combination of high winds and ample interceptive plant surfaces. Lead is not essential to growth and is highly toxic to both plants and a n i r n a l ~ . It~ accumulates ~.~~~ in the roots of plants and is not readily transported to the shoots as shown by solution culture The uptake of lead by plants is influenced by soil properties including soil pH, organic-matter content, soil phosphorus, and cation-exchange ~ a p a c i t y . The ~ ~ ~uptake - ~ ~ of ~ lead by plants has been reviewed by Jones and Clement607and Zimdahl and Koeppe.608 There have been many cases reported of lead poisoning of farm animals owing to consumption of lead contaminated herbage or ingestion of soil with a high lead

G. L. Rolfe and J . C . Jennet, in Proc. Int. Conf. Heavy Metals in the Aquatic Environment, ed. P. A. Krenkel. Nashville, Tennessee, Pergamon Press, 1973, p. 23 1. s y 5 Z . Kerin, in Symp. Proc. Heavy Metals in the Environment, Toronto, Canada 1975, Vol. 11, Part 2, p. 487. 5y6 A. H. Adamson, in 'Inorganic Pollution and Agriculture', M A F F Reference Book 326, HMSO London, 1977, p. 77. "'T. M. Roberts and G. T. Goodman, in 'Trace Substances in Environmental Health', ed. D. D. Hemphill, Univ. of Missouri, Columbia, 1974, Vol. VII, p. 105. G. Tyler, Water, Air Soil Pollut.. 1978, 9, 137. 5 9 9 W. A. Reiners, R. H. Marks, and P. M.Vitousek, Oikos, 1975, 26, 264. "" R. F. Brewer, in 'Diagnostic Criteria for Soils and Plants'. ed. H. D. Chapman, Univ. of California, Div. of Agric. Sci. 1966, p. 2 13. T . C. Broyer, C. M. Johnson, and R. E. Paull, Plant Soil, 1972. 36, 301. Oo2 L. H. P. Jones. C. R. Clement, and M. J. Hopper. Plant Soil, 1973, 38,403. '"'S. C. Jarvis. L. H. P. Jones, and C. R. Clement, Plant Soil, 1977, 46, 371. Oo4 A. J . MacLean, R. L. Halstead, and B. J. Finn, Can. J . Soil Sci..1969. 49, 327. J. E. Miller, J. J. Hassett, and D. E. Koeppe, Commun. Soil Sci.Plant Anal.. 1975, 6,349. R. L. Zimdahl and J. M. Foster, J . Enuiron. Qual., 1976, 5 , 31. "' L. H. P. Jones and C. R. Clement, in 'Lead in the Environment', ed. P. Hepple, Applied Science Publishers, Barking, Essex. 1972, p. 29. R. L. Zimdhal and D. E. Koeppe, in 'Lead in the Environment', ed. W. R. Boggess and B. G. Wixson, Natl. Science. Foundation Washington DC, Rep. No. NSF/RA770214. Castle House Publications Ltd.. 1979, p. 99. sy4

The Elemental Constituents of Soils

173

content.60yv610The biologic effects of lead in fish6" and in domestic animals612 have been reviewed and a comprehensive assessment of the behaviour of lead in human and animal nutrition has been made by Underwood." Literature reviews on the behaviour of lead in the environment have been prepared by L a g e r ~ e r f f ,Bethea ~ ~ ~ and Bethea,613 Nriagu,'I4 and Boggess and Wix~on."~ 14 Nitrogen, Phosphorus, and Sulphur

Nitrogen.-Geochemistry. Nitrogen is the major constituent of the earth's atmosphere and, because of the stability of the gaseous N,molecule, it is enriched in the atmosphere relative to the earths crust in the proportion of 3 : 1 by weight. In the minerals of igneous rocks N is present largely in a 'fixed' ammonium form. The N content of minerals and rocks varies widely but the levels in some minerals are: quartz 0-27 mg kg-l, mean 13 mg kg- I, plagioclase 3-48 mg kg-l, mean 22 mg kg-', and biotite 10-266 mg kg-', mean 55 mg kg-'. Nearly all intrusive rocks contain nitrogen varying from 2 to about 50 mg kg-I by weight. Volcanic rocks generally contain about twice the nitrogen content of intrusive rocks and average 37 mg kg-'. The occurrence of nitrate nitrogen in igneous magmas is improbable because of the low oxygen potential. Nitrate nitrogen is found, however, in natural waters and sediments, with near-shore sediments often containing up to ten times the N content of deep-sea sediments. Although nearly 80% of the atmosphere is nitrogen, atmospheric nitrogen is thought to amount to only 6% of the total N of the whole earth with almost all the rest contained in the deep-seated rocks of the The crustal average for nitrogen has been estimated to be 20 mg kg-1.75 Weathering and Mobility. Nitrogen released by the weathering of rocks generally undergoes oxidation. Under natural conditions nitrate is the predominant stable nitrogen compound and all nitrogen converted into this form biologically is probably carried into the oceans as NO;. The bulk of the nitrogen in ocean waters is, however, in the form of N,, the ratio of molecular to combined N being about 25. Ammonia, nitrite, and nitrate play an important role in the biological cycle in natural water. Nitrate in river waters worldwide averages 1 mg kg-' and drinking water should not contain more than 10 mg nitrate per litre. Ammonium forms are only a transitory constituent in waters as it is easily absorbed. Ammonium nitrogen is adsorbed and fixed by micas and other layer lattice silicates, and biotite appears to be particularly effective in fixing ammonia. Upon release from rocks or fixation from the atmosphere by micro-organisms, nitrogen is incorporated into organic matter, mainly as proteins or amino-acids. H. J. Hapke and E. Prigge, Berlin. Muench. Tieraerztl. Wochenschr., 1973,86,410. D. J. Kelliher and D. B. R. Poole, lsr. J. Agric. Res.. 1973. 12. 259. A. L. Aronson, J. Wash. Acad. Sci., 1971, 61, 124. 6 1 2 A. L. Aronson,J. Wash. Acad. Sci., 1971, 61, 110. 6 1 3 R. M. Bethea and N. J . Bethea, Residue Rev., 1975, 54, 55. 6i4 J . 0. Nriagu (ed.), 'The Biogeochernistry of Lead in the Environment. Part A. Ecological Cycles', Elsevier, 1978,422 pp. 6 ' 5 W. R. Boggess and B. G. Wixson, ed. 'Lead in the Environment', National Science Foundation Rep. No. NSF/RA-770214, Castle House Publications Ltd., 1979. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-1/7, Springer-Verlag, Berlin. '09

610

174

En L' ironm en ta1 Chemistry

Soil Contents. In comparison with the original rocks, soils are greatly enriched in nitrogen, even though the N present in soils is a negligible part of the global total. The bulk of soil nitrogen is in organic forms6" largely accumulated from the elemental form in the atmosphere by microbiological fixation processes. In agriculture, an important part of the nitrogen used by plants is supplied by nitrogenous fertilizers, derived mainly from elemental nitrogen by industrial chemical-fixation processes. Nitrogen is one of the primary constituents of all living matter. The average N content of plants is 3% of the dry matter and much organic nitrogen is returned to the soil upon decay of plant materials. The nitrogen content of soils is highly variable: desert soils contain about 0.1% N and highly organic soils up to 2% N. Most values in normal soils lie between 0.2 and 0.3'%.61x Bremner6IYhas reported that the total N content of soils ranges from < 0.02% in subsoils to > 2.5% in peats; the surface layer of most cultivated soils contains between 0.06 and 0.5% N. The ploughed layer of the majority of cultivated soils contains between 0.02 and 0.4% nitrogen by weight,620however, a range of 0.02--0.5% with a mean of 0.2% has been reported by B ~ w e n . ' ~ Elemental nitrogen (N,) is present in gaseous form in the soil atmosphere, which often occupies about one quarter of the soil volume, and in dissolved form in the soil water, which also occupies about one quarter of the soil volume. In inorganic combined form, nitrogen also occurs in soils as nitrous oxide (N,O), nitric oxide (NO), nitrogen dioxide (NO,), ammonia (NH,), ammonium (NH;), nitrite (NO;), and nitrate (NOT). The latter three are ionic forms found in the soil solution and are the forms used by plants although they may together constitute less than 2% of the total nitrogen in soils. Most of the N present in soils is in organic forms, and the organic N added to soils in plant and animal residues is largely proteinaceous in nature. Upon decomposition by microbes proteins release amino-acids, aminosugars, and other products into the soil, including inorganic forms which may then become available to plants. The nitrogen cycle and the chemical and biological transformations of nitrogen in soils have been discussed by many aUthors.74.5Il,620-624 V arious aspects of the chemistry and availability of nitrogen in soils have been reviewed in a monograph edited by Bartholomew and Clark,625and the global biogeochemical cycles of nitrogen, phosphorus, and sulphur have been reported in a SCOPE Report edited by Svensson and Soderlund.626 J . M. Bremner. in 'Soil Nitrogen', ed. W. V. Bartholomew and F. E. Clark. Am. SOC.Agron, Madison, Wisc.. USA. Monogr. No. 10, 1965. p. 63. 'IR F. J . Stevenson. in 'Soil Nitrogen'. ed. W . V . Bartholomew and F. E. Clark. Am. SOC. Agron. Madison, Wisc., USA, Monogr. No. 10, 1965. p. I . b ' Y J . M. Bremner, in 'Methods of Soil Analysis. Pt. 2, Chemical and Microbiological Properties', ed. C. A. Black, el a/., Am. SOC.Agron. Madison. Wisc.. USA. Monogr. No. 9. 1965. 1149. C. A. Black. 'Soil Plant Relationships'. 2nd. Edn.. J . Wiley and Sons. N.Y.. 1968. 792 pp. '2' I. L. Stevenson, 'Biochemistry of Soil' in 'Chemistry of the Soil'. 2nd Edn. ed. F. E. Bear. ACS Monogr., No. 160. Reinhold. N.Y.. 1964. p. 242. '*'J. W. Parsons and J. Tinsley. 'Nitrogenous Substances' in 'Soil Components. Vol. 1, Organic Components'. ed. J. E. Gieseking. Springer-Verlag, N.Y.. 1975. p. 263. R. D. Hauck and J . M. Bremner,Adr..Agron.. 1976. 28. 2!9. '24 J. 0. Nriagu (ed.), 'Environmental Biogeochemistry'. Proc. 2nd Int. Symp. on Environmental Biogeochemistry, Ann Arbor Science. Michigan, 1976. p. 225. 6 2 5 W. V. Bartholomew and F. E. Clark (ed.). 'Soil Nitrogen', Am. Soc. Agron. Inc.. Madison, Wisc., IJSA, Monogr. No. 10. 1965. pp. 615. B. H. Svensson and R. Soderlund (ed.). S C O P E Report 7. Ecological Bulletin No. 22. Swedish National Sci. Res.. Council. Stockholm. 1975, 192 pp.

'I7

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The Elemental Constituents of Soils

175

Phosphorus.-Geochemistry. The most important and abundant phosphate mineral is apatite Ca,(F, CI, OH)[PO,J,, the structure of which tolerates numerous replacements both for calcium (Na, Sr, Ba, Cd, Pb, Re, Th, U), and for PO,(SO,, SiO,, CO,, AsO,, VO,). Some phosphorus is present in silicate minerals owing to isomorphous replacement of Si4+by P5+in SiO, tetrahedra. The phosphorus content of igneous rocks generally varies between 0.0 and 0.9% and there is a great variation in content even within rocks of a similar type. There is, however, a gradual decrease in phosphorus content in magmatic rocks from ultrabasic to acid igneous types. A crustal average of 1050 mg P kg-' has been reported with a basalt average of 1400 mg P kg-' and a granite average of 700 mg P kg-1.75 Weathering and Mobility. Practically all of the phosphorus in nature is present as phosphate, which is released by weathering of the phosphate minerals. Apatite is soluble in acid solutions and much of the released phosphate can be precipitated as Al-phosphate (variscite) under such conditions. The low solubilities of Ca-, Fe-, Al-, and Pb-orthophosphates, greatly influence the behaviour of phosphorus in natural processes. Adsorption processes are also important particularly in soils where clay minerals and also iron, aluminium, and manganese hydroxides interact with phosphate ions in the soil solution. Soil Contents. Phosphate ions, whether released by mineral weathering or applied as fertilizer, are rapidly adsorbed in soils by several mechanisms. Over the range of phosphate concentrations found in soil solutions, Fe3'-phosphate complexes are the predominant species in solutions of pH less than 1.3, A13+-phosphate complexes in the range pH 1.3-4.3, and hydrolysed phosphate ions in the range pH 4.3-7.2 (see ref. 894). At a pH greater than 7.2 calcium phosphate and magnesium phosphate complexes are predominant. Phosphorus is relatively stable in soils, and is not lost readily by volatilization or leaching. This is in contrast to the behaviour of inorganically combined forms of nitrogen, which are much less stable in soils and are lost by both processes. The total phosphorus content of soils is, however, relatively low, most soils in the USA containing between 0.022 and 0.083% total P. An average of 0.062% in the plough layer of the cropland of the USA has been reported,620however, a range of from 0.002-0.6% in 863 topsoils from the United States, with a mean of 0.042% has also been f o ~ n d . 'A~ range of from 0.0035-0.53, with a median content of 0.08% has also been reported.74 The phosphorus in soils occurs almost exclusively as orthophosphate in either inorganic or organic combination, but small amounts of phosphonate have recently been detected in some New Zealand soils (see ref. 895). The nature and behaviour of inorganic phosphorus in soils has been reviewed by L a r ~ e n " and ~ the chemistry of phosphate minerals in soils by Lindsay and Vlek.62RStudies on the chemical nature of organic phosphorus in soils have shown that inositol phosphates predominate, in some cases accounting for more than 50% of the organic phosphorus and about 25% of the total soil phosphorus. Phospholipids and nucleic acids 627 628

S. Larsen. A h . Agron., 1967. 19, I5 I . W. L. Lindsay and P. L. G. Vlek, in 'Minerals in Soil Environments'. ed. J . B. Dixon and S. B. Weed, Soil Sci. Soc. Am.. Madison. Wisc.. USA. 1977. p. 639.

176

Environmental Chemistry

have also been identified.629The nature of organic phosphorus compounds in soils has been reviewed by Anderson630and Dalal."' The phosphorus cycle in soils has been reviewed by several

Sulphur.-Geochemistry. Sulphur, in its various forms, is distributed rather heterogeneously throughout the earth's crust. Much is concentrated in sedimentary materials and the oceans are the largest reservoir of dissolved sulphate. Sulphur occurs in four oxidation states in geological environments: as S2- in sulphides etc., as S, in elemental sulphur, as S'" in sulphur dioxide and as Svl in gases and sulphates and these are present in solid, liquid, and gaseous phases in the lithosphere, the atmosphere, the hydrosphere, and the biosphere. The sulphur content of rock-forming silicates is usually less than 100 mg kg-'. Metal sulphides often exist, however, as minute inclusions in all kinds of silicate minerals especially in basic rocks. Sulphate, on the other hand, is more homogeneously distributed in silicates. Pyrite (FeS,) and pyrrhotite ( F e n s n + are the most common sulphide minerals in the earths crust and many of the metals of economic importance occur as sulphides precipitated in hydrothermal or liquid magmatic ore-forming processes. The average sulphur content of ultrabasic rocks is 2850 mg kg-', of basalts 520 mg kg-', and of basaltic glasses 1020 mg kg-'; of granitic rocks 300-400 mg kg-I, and of pelitic sediments 2400 mg kg-'. The mean S contents of various groups of metamorphic rocks, amounting to 175 samples in all, ranged between 680 and 1050 mg kg-1.637The crustal average has been reported to be 260 mg S kg-1,75but the biogeochemistry of sulphur has been discussed by T r ~ d i n g ewho r ~ ~reports ~ that the average concentration of sulphur in the earths' crust is about 500 mg S kg-'. Weathering and Mobility. The sulphur released by decomposition of rocks may often be precipitated in sediments as sulphides, commonly with iron, released as gaseous H2S or oxidized to relatively soluble sulphate. In the atmosphere, sulphide species whether they are aqueous, solid, or gaseous are rapidly oxidized to sulphate. In the E , and p H conditions found in the environment of weathering rocks, the important forms of sulphur are SO:-, HS-, and H,S aq. Pyrite and other sulphide material in mining spoil heaps and waste dumps, upon oxidation give rise to waters of low pH containing large amounts of sulphates and high metal concentration^.^^^ This often arises in coal-waste dumps, as coal typically contains 1% sulphide. Sulphate produced by weathering processes is generally rapidly lost in run-off water G. Anderson, in 'Soil Biochemistry', ed. A. D. McLaren and G . H. Peterson, Dekker, N.Y., 1967, Vol. 1, p. 67. 630 G. Anderson, in 'Soil Components, Vol. 1, Organic Compounds', ed. J. E. Gieseking, SpringerVerlag, Berlin, 1975, p. 305. 631 R. C. Dalal, A d v . Agron., 1977, 29, 83. 6 3 2 D. S. Hayman, in 'Soil Microbiology, A Critical Review', ed. N. Waller, Butterworths, London, 1975, p. 67. 6 3 3 B. J. Halm, J. W. B. Stewart, and R. L. Halstead, in 'Isotopes and Radiation in Soil-Plant Relationships including Forestry', IAEA, Vienna, 1972, p. 57 1. 634 R. L. Halstead and R. B. McKercher, in 'Soil Biochemistry', ed. E. A. Paul and A. D. McLaren, Dekker, N.Y., 1975, Vol. 4 , p . 31. 635 U. Pierrou, Ecol. Bull., Swedish National Science Research Council, 1975, No. 22, p. 75. 636 B. L. Baser and S. N. Saxena, J . Indian SOC.Soil Sci., 1967, 15, 135. 6 3 7 K. H. Wedepohl (ed.), 'Handbook of Geochemistry', I1-2/ 16, Springer-Verlag, Berlin. 63R P. A. Trudinger, in 'Sulphur in Australian Agriculture', ed. R. D. McLachlan. Sydney Univ. Press, 1975, p. 1 I .

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177

The Elemental Constituents of Soils

except for that fraction taken up by plants or micro-organisms. Soluble sulphate is carried by rivers into the oceans which contain 7% of the total crustal sulphur. Sulphate concentrations may reach high levels in closed basins and can be precipitated, generally as gypsum, CaS04,2H,0, on evaporating. Sulphur is released into the atmosphere as H,S by natural processes and as SO, from industrial sources. Oxidation of these sulphur gases in the atmosphere produces acid rainfall (pH 4.0). Sulphur is essential to most forms of life, which convert much of it to organic compounds. The great majority of crude oils contain 0.1-3% S, whereas organic sulphur in coal ranges between 0.5 and about 5%.

Soil Contents. The range of total sulphur contents in 1267 soils from various parts of the world is from 3-8200 mg kg-' with a mean of 433 mg kg-' (Table 31). Total sulphur in the soils listed by Whitehead639range from 22-8000 mg kg-', excluding marine and tidal marsh soils which contain up to 3.5% S. In most soils, total sulphur values fall within the range 100-500 mg kg-', although high levels are found in peats, saline soils, and acid sulphate soils.640A range of total sulphur in soils of 30-1600 mg kg-' with a median of 700 mg kg-' has been reported by B ~ w e n . ' ~ The geochemical cycles of C, H, 0, N, P, and S are inter-related in the biosphere because these elements are accumulated by photosynthesis and other biological growth processes, transformed together by respiration and other metabolic Table 3 1 Sulphur soil contents (mg S kg-') Soils Range 80- 1094 30 soils, Canada, 15 profiles 13 1-940 18 topsoils, Minnesota, USA 64- 1400 15 topsoils, Queensland, Australia 138-7408 16 topsoils, England 56-6 18 37 topsoils, Iowa, USA 38-302 3 1 subsoils, Iowa, USA 88-760 54 topsoils, Canada 120-8200 104 top and subsoils, Finland 43-580 12 topsoils, Brazil and Iowa 199-3 39 2 267 topsoils, Wales 115-1344 268 subsoils, Wales 25-290 45 topsoils, Nigeria 10- 1630 156 topsoils, New Zealand, 52 profiles 300- 1790 50 topsoils, Scotland 3-725 165 soils, Queensland, Australia, 55 profiles Overall Mean Content 433 mg S kg-' 1267 Soils

Mean 364 50 1 426 91 1 292 122 284 608 243 7 10 356 74 440 639 145

ReJ a b C

d 645 645 e

f g h

h 1

j 646 649

a L. E. Lowe, Can. J . Soil Sci., 1965, 45, 297; G. W. Rehm and A . C. Caldwell, Soil Sci., 1968, 105, 355; 'J. R. Freney, G. E. Melville, and C. H. Williams, ibid., 1970, 109, 310; d L . H. P. Jones, D. W. Cowling, and D. R. Lockyer, ihid., 1972, 114, 104; J. R. Bettany, J. W. B. Stewart, and E. H . Halstead, Soil Sci. SOC.Am. Proc., 1973, 37, 915;/J. Korkman. J . Sci. Agric. Soc. Finland, 1973, 45. 121; R A .M. L. Neptune, M. A. Tabatabai, and J. J. Hanway, Soil Sci. Soc. Am. Proc., 1975, 39, 51; C. Williams, J . Agric. Sci., 1975, 84, 445; ' W. 0. Enwezor. Geoderma, 1976, 15, 40 I ; j A. J. Metson and T. W. Collie, N . Z . J . Sci., 1976, 19, 223

639 640

D. C. Whitehead, Soils Fert., 1964, 27, 1. J. D. Beaton, G. R. Burns, and J. Platou, Sulphur Institute Tech. Bull. 14, 1968, 56 pp.

178

En vironmen ta I Chemistry

processes, and released into various organic and inorganic products of decay. The sulphur cycle is one of the most complex because sulphur forms a large variety of organic and inorganic species and microbiological transformations are often involved. The cycle of sulphur in the e n ~ i r ~ n m e n t , and ~ ~ in * ~soils639*641-645 ~~*~~~*~~~ has been reviewed and discussed. Inputs of sulphur into soils, whether from rainfall or from fertilizers, are normally in the form of water-soluble sulphates and this is the form in which plant roots absorb sulphur from the soil solution. Sulphate is adsorbed by soils to a greater extent than nitrate but much less strongly than phosphate so there is little sulphate accumulation in most soils except where these are calcareous. The inorganic fraction of sulphur in soils, which is mainly sulphate, is partly retained by clay minerals and partly exists as water-soluble sulphates. Most sulphur in surface soils is present, however, in soil organic matter and thus its distribution in soils is very In a group of acid surface much associated with that of organic C and N.6399646 soils, derived from a range of parent materials, over 90% of the total sulphur has been found to be in organic ~ o m b i n a t i o n The . ~ ~organic ~ ~ ~ ~fraction ~ of sulphur is thought to contain two main groups of compounds, organic sulphates and carbon-bonded The carbon-bonded sulphur appears to be a stable and integral part of humus and consists mainly of the amino-acids, methionine and cysteine and their derivatives. Subsoils usually contain less total sulphur than topsoils, but a higher proportion is inorganic.650 The chemical nature of sulphur compounds in soils has been reviewed by Williams651*652 and a review of sulphur in New Zealand soils prepared by M e t ~ o n . ~ ~ ~ Sulphur is a major nutrient element and is essential to plant growth for the synthesis of the amino-acids, methionine and cysteine, and thus for the formation of proteins. It is also a component of some enzymes, vitamins, and oils and is essential to the growth of animals.654

“’ R. W. Fairbridge (ed.), ‘The Encyclopedia of Geochemistry and Environmental Sciences’, Academic Press, 1972, 1321 pp. J. R. Freney and A. J. Nicholson (ed.), ‘Sulphur Cycling in Australian Ecosystems’, Aust. Acad. Sci., 1980,268 pp. b43 K. D. McLachlan (ed.), ‘Sulphur in Australian Agriculture’, Sydney Univ. Press., 1975, 261 pp. 644 M. J . Frissel (ed.), Proc. Symp. Cycling of Mineral Nutrients in Agricultural Ecosystems, Amsterdam, Elsevier, 1978, 356 pp. 645 B. W. Bache and N. M. Scott, in Proc. Int. Symp. Sulphur Emissions and the Environment, SOC. Chem. Ind., London, 1979, p. 242. 646 M. A. Tabatabai and J. M. Bremner, Soil Sci., 1972, 114, 380. 64’ N. M. Scott and G. Anderson, J . Sci. Food. Agric., 1976, 21, 358. 648 M. A. Tabatabai and J. M. Bremner, Agron. J., 1972, 64,40. 649 G. Anderson, in ‘Soil Components, Vol. 1, Organic Components’, ed. J . E. Gieseking, Springer-Verlag, N.Y., 1 9 7 5 , ~333. . 650 M. E. Probert, CSIRO, Australia Div. Soils, Tech. Pap. No. 31, 1977, 20 pp. 6 J 1 C. H. Williams, in ‘Handbook on Sulphur in Australian Agriculture’, ed. K. D. McLachlan, CSIRO. Melbourne, Australia, 1974, p. 16. C . H. Williams, in ‘Sulphur in Australian Agriculture’, ed. K. D. McLachlan, Sydney Univ. Press, 1975, p. 21. 653 A. J. Metson, N.Z. J . Agric. Res., 1979, 22, 95. 654 W. G. Hoekstra, Ann. N . Y . Acad. Sci., 1972, 199, 182. 642

The Elemental Constituents of Soils

179

15 Hydrogen and Oxygen

Hydrogen.-Geochemistry. Hydrogen occupies a structural position in about one third of all known minerals. It is normally bonded to oxygen and is present as hydroxyl groups in a variety of minerals. Hydrogen is present in the water molecule, the principal component of the hydrosphere, but water is also present in many rock-forming minerals. Hydrogen also occurs rarely as the ammonium ion, NH4+, sometimes replacing K+ in a few minerals, as CH,, and as free hydrogen gas which is present in the atmosphere to the extent of 0.5 mg kg-I. Water has been estimated to make-up 1.3% of the earths crust.’12 Weathering and Mobility. The geochemistry of hydrogen is largely that of water which takes part in the breakdown of rocks and the formation of sediments. Water is therefore one of the principal agents in the chemical weathering of rocks and in the transport of weathered material in solution and suspension into the rivers and oceans. The cycle of hydrogen in the environment has been discussed by B ~ w e n ~ ~ and the hydrologic cycle, the continuous circulation of water and water vapour over and Fairb~-idge.~~l the entire earth, by Soil Contents. Hydrogen in soils is present largely as water or in the hydroxyl groups of soil minerals and to a small extent in organic matter. The water content of soils is highly variable depending upon rainfall and soil-drainage conditions, but the liquid phase can often occupy one quarter of the soil volume. Hydroxides and oxyhydroxides of elements such as aluminium and iron, together with clay minerals which contain water and OH-, are some of the major weathering products of rocks and minerals and play an active part in the surface reactivity and nutrient supplying processes of soils. Water is essential to all organisms and plants die when the soil contains insufficient water to support growth, as in times of drought. The amounts of hydrogen converted into organic matter by plants are small compared with the mass of water transpired. Exchangeable hydrogen in the soil represents only a small proportion of the total content but has a large influence on reactions in soils. Hydrogen ion activity in soils, usually measured as the soil pH, has a large influence on the loss of nutrients by leaching, on the availability of nutrients, and on plant growth. Oxygen.-Geochemistry. Oxygen is by far the most abundant element in the earth’s crust and occurs in well over half the known minerals as simple oxides, complex oxides, oxyanions, hydroxides, and hydrates. Most of the rock-forming minerals have oxygen contents in the range 30-50% by weight, whereas igneous rocks contain 40-50%. There is a good correlation between the oxygen and the S O , contents of igneous rocks. Most sedimentary rocks contain between 40 and 50% oxygen and the purest quartzites approach 53%. Pure limestones have oxygen contents between 48% (calcite) and 52% (dolomite), whereas shales and clays generally contain 48%.656A crustal average of 46.2% has been estimated by Taylor. 75 6s5

65b

V . T. Chow, in ‘Handbook of Applied Hydrology’, McGraw Hill, N.Y., 1964, p. 1 . K . H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-1/8, Springer-Verlag, Berlin.

Enilironmental Chemistry

180

Weathering and Mobility. The oxygen cycle is the most complicated of all the element cycles because of the large number of inorganic chemical species containing the element. Oxygen is more widely distributed than any other element owing to its presence in a great variety of silicates and metallic oxides. It is a component of water, is important in organic compounds and life processes, and exists as free oxygen in the atmosphere. The earth's atmosphere contains about 2 1% oxygen and many weathering processes involve oxidation coupled with hydration. The cycle of oxygen in the environment has been discussed by Fairbridge"' and B ~ w e n . ~ ~ Soil Contents. The solid phases (mineral and organic) frequently make up only about 50% of the soil volume, the other half being occupied by the soil solution and the soil atmosphere. The liquid and gas phases vary rapidly in their relative proportions as the liquid phase (water) drains away or is used by plants. The soil atmosphere has a composition of approximately 80% nitrogen, 20% oxygen, and small amounts of carbon dioxide."* Measurements of the oxygen and carbon dioxide contents of soil atmospheres have been reviewed by the oxygen contents of different soils ranging between 10 and 21% by volume depending upon such factors as type of cropping and time of year. The bulk of the inorganic material of soils consists of the four elements 0, Si, Al, and Fe and at least 90% of the mineral matter of most soils is composed of minerals containing the combined oxides of Si, Al, and Fe, although calcareous soils can contain as much as 20-50% CaCO,. Most organisms require oxygen for respiration and other biochemical and metabolic processes. During photosynthesis carbon dioxide from the atmosphere is absorbed by plants and incorporated into carbohydrates, cellulose, and other oxygen-containing organic molecules that ultimately decompose in the soil. Soil organic matter retains many oxygen-containing reactive groups, such as -OH and -COOH, which play an active part in soil processes. A median value for the oxygen content of soils of 49% has been reported by B ~ w e n . ~ ~ 16 The Halogens: F, CI, Br, and I

C ~ r r e n s , ~in~a' general review of the geochemistry of the halogens, has suggested that a portion of the halogens found in soils is contributed by rainfall but that the major part comes from rock weathering.

Fluorine.-Geochemistry. Fluorapatite Ca,F(PO,),, mica, and fluorite CaF, are common F-containing minerals in granites, apatite being stable, mica moderately stable, and fluorite more readily soluble. Fluorine replaces OH in the structure of apatite, a common accessory mineral in rocks, and fluorapatite is the least soluble of the apatites. The average contents of F in various rock types in mg kg-l have been reported to be: basalt, 360; andesite, 210; rhyolite, 480; phonolite, 930; gabbro and diabase, 420; granite and granodiorite, 870; alkalic rocks, 1000; limestone, 220; dolomite,

'"C. W. Correns. Phys. Chem. Earth, 1956, 1, 18 I .

The Elemental Constituents of Soils

181

260; sandstone and greywacke, 180; shale, 800; and oceanic sediments, 730.65' In general, ultrabasic rocks (mean, 100 mg F kg-') and intermediate rocks (mean, 400 mg F kg-') have lower F contents than rocks higher in silica (mean, 800 mg F kg-1).659

Weathering and Mobility. The suggestion that F is lost during the weathering of F-containing rocks and minerals is borne out by the following comparison of soil and rock contents. In a study of 46 Russian profile soil6' there was a tendency for F contents to increase with increase in depth. Contents were higher in clayey than in sandy soils. On the basis of about 250 analyses of soils from various parts of the world it was concluded that the average F content of soils is about 200 mg kg-', which contrasts sharply with the value of 650 mg kg-' reported by Fleischer and Robinson658as the average content of the continental rocks of the earths crust. Koritnig660has reported that F was leached out very soon after the onset of weathering of a granitic rock. In a study of 10 Scottish soils, derived from different parent materials, the average F content was 410 mg kg-', again considerably lower than the crustal rock average, and soils on acid igneous parent materials had the lowest contents.69 Much of the F in soils is in insoluble forms. It has been shown by several workers that the amount of F taken up by plants from the soil is usually unrelated to the F content of the soil. Soil type, calcium and phosphorus content, and soil reaction (pH) are controlling factors in the mobility of F. It has been shown that addition of large quantities of soluble fluoride-containing minerals to unlimed acid soils will result in increased fluoride uptake by the plant and possible injury, similar to that caused by exposing the leaves to hydrogen fluoride.661MacIntire et aL6'j2have shown, however, that the high F in phosphatic fertilizers had no detrimental effect on germination or plant growth in well-limed, neutral soils. Analyses of rain water indicate that significant amounts of F are washed down from the atmosphere 663 especially in populated areas where coal burning and manufacturing processes, such as aluminium smelting and brick making, may 665 Fluorine recovery systems have been installed in phosphorusrelease F.6647 processing plants after it was recognized that effluent fumes could contribute to atmospheric-derived contamination of forage crops and to the related fluorosis in livestock. Considerable amounts of F are also released during volcanic eruptions in gaseous forms and in ash.666 M. Fleischer and W. 0. Robinson, R . SOC.Can. Spec. Pap. 1963, No. 6,58. K . H. Wedepohl (ed.), 'Handbook of Geochemistry', 11- 1/9, Springer-Verlag, Berlin. 660 S. Koritnig, Geochim. Cosmochim. A c f a , 195 1, 1, 89. 6b1 R. F. Brewer, in 'Diagnostic Criteria for Plants and Soils', ed. H. D. Chapman, Univ. California, Div. Agric. Sci., Riverside, 1966, p. 180. 662 W. H. Maclntire, S. H. Winterburg, J. G. Thomson, and B. W. Hatcher, Ind. Eng. Chem., 1942, 34, 1469. 6 6 3 W. H. MacIntire, L. J. Hardin, and M. H. Buehler, Uniu. Tennessee Agric. Expt. Sla. Bull., 1958, No. 219,33 pp. 664 H. Robak, in 'Air Pollution', Proc. 1st. Europ. Congress on the Influence of Air Pollution on Plants and Animals, Pudoc, Wageningen, The Netherlands, 1969, p. 27. '"R. Allcroft, K . N. Burns, and C. N. Herbert, 'Fluorosis in Cattle', Animal Diseases Surv. Report. No. 2, HMSO, London, 1965. 666 E. H. Einarsson, Arsrit. Raeklunarfelags Nordurlands, 1974, 71, 96. 658

659

Environmental Chemistry

182 Table 32 Fluorine soil contents (mg F kg-I) Range Soils 10-7070 302 soils (various locations) earlier compilation reporting values up until 1958 130-5600 3 3 1 topsoils, Tennessee 104-284 9 topsoils, Tennessee 65 soils, India, 9 profiles 6-62 22-230 20 topsoils, New Zealand 70-618 20 1 topsoils, Illinois 40 topsoils, Illinois 275-390 23-700 10 topsoils, Scotland 136-990 55 topsoils, Pennsylvania 693 Soils Overall Mean 270 mg F kg-'

Mean 295

R eJ 658

849 189 30 134 271 348 410 377

663 663 a b 672 613 69 C

* Omitting values in ref. 663 because many are contaminated a U . C. Shukla and K. G. Prasad, Indian J. Agric. Sci.,1973, 43, 934; T. R. Manley, J. J. Stewart, J. A. White, and J. L. Harrison, N . Z . J . Sci., 1975, 18, 433; L. Gilpin and A. H. Johnson, J . Soil Sci. SOC.Am., 1980,44,255

Soil Contents. The total F contents of 693 soils from various parts of the world range from 6 to 7070 mg kg-' with a mean content of 270 mg kg-' (Table 32). An earlier c ~ m p i l a t i o nreports ~~ the range of total F in soils to be 20-700 mg kg-', with a median content of 200 mg kg-'. Many soils, especially those with high apatite contents, contain relatively large amounts of F. Phosphatic fertilizers usually contain appreciable amounts (commonly more than 1% F), as do certain slags and liming r n a t e r i a l ~ . ~Use ~ ' of these as fertilizers would add to the natural fluorides in the soil. Since the early study of Vinogradov,6Rwork on the F content of soils has been concentrated mainly in areas where soil levels are naturally high or where they have been increased by industrial activity. Phosphorites contain on average 3 1 000 mg F kg-' and the element is always present in phosphatic fertilizers, soils, and plants. The fluorine concentration in these materials, though variable, is respectively of the order 3 x lo4, 3 x l o 2 and 3 x loo mg kg-' and thus falls by two orders of magnitude at each stage in the sequence: fertilizers --+ soils + plants.669 Several workers have found that, in general, the total F content of soils increases with increase in depth and also that F is considerably concentrated in the soil colloidal matter and have suggested that the main source of F in ordinary soil may be micaceous clays.68~670*671 This conclusion is supported by the work of Omueti and Jones6'* who carried out a detailed study of the regional distribution of F in 201 Illinois soils. Fluorine was found to be most abundant in the clay-rich soils of central and north-eastern Illinois, but there was no clear-cut distribution pattern related to either parent material or to soil genesis. A statistical evaluation showed that the contents of clay and organic carbon and soil pH level were the soil D. J. Swaine, 'The Trace Element Contents of Fertilizers', Commonwealth Bureau of Soils, Harpenden, Tech. Commun. No. 52, 1962. M. Fleischer, Ann. N . Y . Acad. Sci., 1972, 199, 6. h69 S. Larsen and A. E. Widdowson, J . Soil Sci., 197 1, 22, 210. 670 M. Piotrowska and K . Wiacek, Rocz. Nauk. Roln., Ser. A , 1975, 101, 93. 6 7 1 J. A . 1. Omueti and R. L. Jones, J . Soil Sci. Soc. Am., 1980, 44, 247. 6 7 2 J. A. 1. Omueti and R. L. Jones, J . Soil Sci.SOC. Am., 1977, 41. 77 1.

667

The Elemental Constituents of Soils

183

parameters primarily responsible for the origin and for retention of native F in Illinois soils. In an extensive study of F in the soils of Maury County, Tennessee,663 where livestock problems owing to fluorosis had been encountered, soil levels in 33 1 surface samples ranged from 130-5600 mg kg-' with an unusually high mean figure of 849 mg kg-'. An interesting study of the F content of soils to which rock phosphate or superphosphate had been applied over a period of 67 years has been carried out."' Between 1904 and 1971, the mean contents in Morrow plot soils varied from 275-390 mg kg-I. The cause of the variation in F content was shown to be related to phosphorus fertilization practices. Much of the F added to soils in the form of rock phosphate between 1904 and 1924, was still retained in 1955. The average loss of F from the soil per annum between 1924 and 1944 was calculated to be about 2.5 mg kg-I. Fluorides added to soils also form insoluble compounds such as calcium fluoride, fluorapatite, or aluminium fluorosilicates. Fluorine was readily lost, however,67' from minerals in acid horizons of soils developed in humid temperate climates and soil organic matter was found to contain only 9 mg F kg-' and therefore contributed very little to the total F content of soils. Fluorine is not essential to the growth of plants, but is essential to the growth of animals and for the production of sound teeth in mammals.96 Most food and feed crops contain between 1-3 mg F kg-' and it is recommended that drinking water should contain 1 mg F kg-I. Fluorine can also be detrimental to health and most problems arise due to air pollution from industrial activities such as aluminium smelting and brick-making. Some animals may be detrimentally affected by eating forage containing more than about 40 mg F kg-1.96Most cases of high F contents in herbage arise from material deposited from the atmosphere onto the leaves of plants rather than from uptake by plants through the roots.

Chlorine.-Geochemistry. Varying amounts of water-soluble chlorine have been found in igneous rocks; some of this is probably due to contamination by seawater and other fluids. Sedimentary rocks deposited in a marine environment would derive sodium chloride from sea water, whereas chloride is the major anion in marine evaporites. There is considerable variation in the CI content of similar rock types but many igneous rocks contain 50-400 mg C1 kg-I (see ref. 813) and a crustal average of 130 mg C1 kg-' has been reported.75 Weathering and Mobility. Much of the chlorine in minerals is present as chloride. Most chlorides are ionic in character and much of the chloride released during weathering is easily soluble in water. In natural waters it occurs almost exclusively as the chloride anion which is not adsorbed to any marked degree on mineral surfaces. Much chloride therefore enters the oceans. Soil Contents. Few analyses of total CI in soils have been published. Total C1 contents in 844 soils from several countries, but mainly from Norway, range from 18-1806 mg kg-I, with a mean of 485 mg kg-I (Table 33). Much of the early Russian work has been summarized by VinogradoP who reported Cl contents in 3 1 Russian soils of 18-900 mg kg-', mean 83 mg kg-'. L i g and S t e i n n e have ~~~~ 673 674

J . A. I. Omueti and R. L. Jones. J . Soil Sci.SOC.Am.. 1977, 41, 1023. J . Lag and E. Steinnes, Geoderma, 1976, 16, 3 17.

Environmental Chemistry

184

Table 33 Chlorine soil contents (mg C1 kg-’) Range Mean Soils 18-900 83 3 1 soils, USSR 5 soils, Brazil 50-1680 485 174-1806 559 700 topsoils, Norway 105 89-110 98 uncult. topsoils, Japan 10 topsoils, Scotland 34-840 310 Overall Mean 485 rng C1 kg-’ 844 Soils

ReJ: 68 70 674 688 69

studied the regional distribution of C1 and the other halogens in Norwegian forest soils. The concentrations of C1, Br, and I showed a rapid decrease at increasing distances from the ocean, indicating that the supply of these elements to the soil is mainly through precipitation from the atmosphere. Strong correlations between C1 and exchangeable Na and Mg in the soils suggested an atmospheric input to soils for these two cations as well. Although chloride is readily leached from soils by rain, substantial amounts are taken up by crops and thus carried over in the plant material from one year to the Chlorine may be introduced into soil through CaCl, or NaCl used as road salt and also from KCl used as a potash fertilizer. Anions such as chloride were found to be more readily leached from soils with high cation-exchange capacities probably as a result of anion exclusion from the immediate vicinity of negatively-charged soil parti~les.~~~-~~~ Environmental pollution involving chloride caused by the use of excessive amounts of salt often arises from the application of de-icing salt to roadways with resultant harmful effects on plants. This has been reported in England,679Sweden,680 Germany,681Canada,682and the USA.683 Chlorine as the chloride anion is an essential element for many animal and plant Chlorine in plants is present groups and is the major anion in mammalian mainly as the chloride anion, but some organic chlorine-containing compounds have been found in marine algae (see ref. 813). The beneficial and toxic effects of chloride in plants have been discussed in a monograph by Arnold684 and the behaviour of chloride in soils and plants reviewed by E a t ~ n . ~ ~ ~

Bromine.-Geochemistry. There are very few naturally occurring bromine minerals. The similarity in the ionic radii of CI (1.8 A) and Br (1.96 A) suggests that the bromide ion might replace the chloride ion in lattice sites. On the other hand C o r r e n ~suggests ~ ~ ~ that Br in minerals probably occurs mainly within liquid inclusions. There is no marked variation in the Br contents between various rock F. M. Eaton, in ‘Diagnostic Criteria for Plants and Soils’, ed. H. D. Chapman, Univ. of California, Div. Agric. Sci., Riverside, 1966, p. 98. 67h G. W. Thomas and A. R. Swoboda, Soil Sci., 110, 163. 677 S. J. Smith, Soil Sci., 1972, 114, 259. 678 D. R. Cameron, C. G. Kowalenko, and K. C. Ivarson, Can. J . Soil Sci., 1978, 58,77. 679 A. W. Davidson, J. Appl. Ecol., 1971, 8, 555. R. Horntvedt, Tidsskr.Skogbruk, 1975, 83, 371. 681 K. Kreutzer, Forslwiss. Centralbl., 1976, 96, 76. 682 R. Hall, G. Hofstra, and G. P. Lumis, Can. J. For. Res., 1972, 2, 244. 6 8 3 A. H. Westing, Phytopathology,1969, 59, 1174. 684 A. Arnold, in ‘Die Bedeutung der Chlorionen fur die Pflanze’. G. Fischer Jena, 1955, 148 pp. 675

The Elemental Constituents of Soils

185

types although volcanic rocks contain more than crystalline rocks. The geochemistry of Br in igneous rocks is very similar to that of C1 and the Br :C1 ratio varies within narrow limits. Bromine is enriched in organic matter and a strong correlation of Br with organic carbon has been shown to exist in sedimentary rocks. W e d e p ~ h suggests l ~ ~ ~ an upper limit of 1 mg Br kg-' for average igneous rocks, although a crustal abundance of 2.5 mg Br kg-' has been reported by Taylor.75

Weathering and Mobility. During the weathering of a granite rock it has been shown that the Br :C1 ratio increased from the unaltered rocks to reach a maximum in the near-surface soil horizons. Only 31Y0 of the Br in the surface horizons was leachable suggesting that the Br is strongly bound by organic matter. Whereas in igneous rocks and volcanic gases Br closely follows C1, in soils and sediments Br behaves similarly to I as both are strongly biophilic and are enriched in organic matter. Most of the world's Br is found in the oceans.685 Soil Contents. Total Br in 1459 soils from various parts of the world ranges from 0.27-848 mg kg-', mean 42.6 mg kg-I (Table 34), which compares with a range from 1-1 10 mg kg-I, median 10 mg kg-' reported in an earlier ~ o m p i l a t i o n . ~ ~ Bromine contents in the A , B, or C horizons of some Russian soil profiles have been reported by Vinogradov68 who noted an accumulation of Br in surface horizons and also in the fine fractions of soils. Bromine was also found to have accumulated in the organic material of muds, soil organic matter, and especially peats. Chlorine, on the other hand, had not accumulated and the C1: Br ratio therefore decreased from the ratio of about 200 found in igneous rocks. The content of Br was greatest in humic horizons and particularly in peats which contained up to 60 mg Br kg-'. L i g and S t e i n n e ~have ~ ~ ~studied Br in 700 Norwegian forest soils and found that Br contents showed a rapid decrease with increasing distance from the ocean. A compilation of Br contents in 79 Japanese soils has been prepared by Yuita and S h i b ~ y a The . ~ ~ samples ~ were from topsoil, subsoil, and soil profiles developed Table 34 Bromine soil contents (mg Br kg-') Soils Range Mean R eJ 4 topsoils, USA 7.4-5 6.5 37 a 54 soils, USSR 0.2 7-4 3 .O 5.7 68 20 soils, Israel, 7 profiles 0.6-8.6 5.8 b 79 soils, Japan 5-848 140 687 6 soils, Brazil 0.9-3 3.0 10 70 700 topsoils, Norway 24 674 4.5-99.6 26 1 topsoils, Wales 11-219 52 C 227 subsoils, Wales < 1-455 48 C 98 forest soils, Japan 60-102 688 93 3.3-25 10 topsoils, Scotland 69 13 1459 Soils Overall Mean 42.6 mg Br mg-I Z. Stelmach, Soil Sci., 1959, 88, 61; 'S. Ravikovitch, M. Margolin, and J . Navrot, ibid., 1961, 92,

85; ' R. I. Bradley, C. C. Rudeforth, and C. Wi1kins.J. Soil Sci., 1978, 29, 258

'"K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-3/35, Springer-Verlag, Berlin. '*'C. Wilkins, J. Agric. Sci., 1978, 90, 109. 6Rl

K. Yuita and M. Shibuya, J . Sci. Soil Manure, Japan, 1973.44, 69.

186

En vironmen tu 1 Chemistry

mainly on volcanic ashes which have high Br contents but some upland and alluvial paddy soils with lower Br contents were also included. Yuita et ~ 1have. reported ~ ~ ~ the contents of Br, I, and C1 in some uncultivated Japanese forest soils. Using an isotope tracer technique, the average retentions of Br, I, and C1 were found to be 74.0, 98.5, and 20.3%, respectively. It was concluded that the accumulation of Br and I in uncultivated soils is due to direct retention of these elements from rain water. Br levels in soils can be enhanced by the use of CH,Br as a soil fumigant,689 or from automobile exhausts 690 where the Br originates from ethylene dibromide used to scavenge Pb from automobile engines using leaded petrol. These latter found, in Glasgow roadside and park-land surface soils, values up to 5 times the 'natural' levels of 11 to 18 mg Br kg-'. No clear relationship has been found, however, between total Br in Pembrokeshire soils and the amount taken up by herbage growing on the same sites.686A literature review on bromine in soils and crops has been prepared by Van E y ~ i n g a . ~ ~ ~ Bromine has not been conclusively shown to perform any essential function in plants, micro-organisms, or animals, although bromide and chloride readily exchange to some degree in body

Iodine.-Geochemistry. Iodine occurs as a minor constituent of various minerals but only rarely forms specific I-minerals. The I contents of all minerals are very similar, there being no enrichment in any particular group probably because it is present as fluid inclusions. It is a biophile element and much of its geochemistry is connected with its involvement in biological processes. Iodine shows little variation in content in igneous rocks with differing silica contents, although in sedimentary rocks, it is often strongly correlated with organic matter. The average I content of most igneous rock groups is within the range 0.08-0.15 mg kg-I, although the average value for alkalic rocks is possibly somewhat higher.691A crustal average for I of 0.5 mg kg-' has been reported by Taylor.75 Weathering and Mobility. According to Goldschmidtlls weathering of rocks results in the release of much of their iodine to form soluble compounds. There is a very marked increase in the iodine content of soils compared with the rocks from which they are formed and many authors, including Goldschmidt, have suggested that much of the I in soils is derived from atmospheric sources. Acid conditions in soils favour the leaching of iodine, whereas the presence of carbonate tends to act as a natural barrier to iodine migration. The clay fractions of soils also fix iodine, a feature which is most marked for illite.691 Soil Contents. The total I contents in 8440 soils from various parts of the world mg kg-', mean 7.08 mg kg-I (Table 35) which compares range from (0.09--210 with range of 0.1-50 mg kg-', mean 5 mg kg-' reported by Vinogradov68and ~ early work on the I 0.1-25 mg kg-', median 5 mg kg-' reported by B ~ w e n . 'The

''' K. Yuita, M. Shibuya, and T. Nozaki, Proc 1lth Int. Congress Soil Sci., Edmonton, Canada, 1978, 1, 260 pp. J. P. N. L. R. Van Eysinga, in 'Bromine in Soils and Crops. A Literature Review'. Rapport Inst. voor Boden Vruchtbarrheid, 1975, No. 5-75,4 pp. 6yo J. G. Farmer and J. D. Cross, Water, Air Soil Pollut., 1978, 9. 193. 69' K . H. Wedepohl (ed.), 'Handbook of Geochemistry'. 11-4/53, Springer-Verlag, Berlin. 68y

The Elemental Constituents of Soils

187

Table 35 Iodine soil contents (mg I kg-I) Mean R e$ Soils Range 692 8.0 trace-2 10 4694 soils, 33 different countries 68 2000 soils, world-wide 0.1-50 5 .O a 0.3-1 1.6 5.5 20 soils, Israel, 7 profiles 230 topsoils, USSR b 1.7 400 topsoils, European USSR 2.65 C 7 6.5 600 topsoils, Norway 2.8-16.6 696 6.5 0.4-25.1 154 soils, England and Wales, 18 profiles 688 39 98 soils, Japan 33-4 1 69 1.3 10 topsoils, Scotland <0.09-2.9 697 9.2 132 topsoils, United Kingdom 0.5-98.2 Overall Mean 7.08 mg I kg-' 8440 Soils a S. Ravikovitch, M. Margolin, and J. Navrot, Soil Sci., 1961, 92,85; N. G. Zyrin, Sou. Soil Sci., 1968, (71, 933; Yu. N. Zborishchuk and N. G . Zyrin, ibid., 1974, (6), 209

content of Russian soils has been summarized by Vinogradov.68 Rocks usually contain very small amounts of I (0.2-4.8 mg kg-') and its accumulation in soils and marine muds relative to its contents in rocks is a striking feature of the geochemistry of I. In general, soils are 20-30 times richer in I than their parent rocks. The amount of I in soils depends largely on the contents of silt and clay, and also on the content of organic matter. Podzols and sandy soils have low I contents but chernozems and chestnut soils are relatively rich. Peats and peaty soils generally have high I contents. Significant correlations have been found between the I content of soils and the incidence of endemic goitre in the population. This commonly occurs in mountainous inland areas where the soils are leached and podzolized and have very low I contents. On the basis of 4696 analyses of I in soils from 33 different countries compiled by the Chilean Iodine Education Bureau covering the period 1825-1956, a range of contents from 'trace' to 210 mg kg-', and a mean of 8.0 mg kg-' can be calculated.692 Much of the more recent work on I in soils has been tabulated by Aubert and P i ~ ~ t aValues . ~ ' ~ in all the soils reported range from 0.07-52 mg kg-' and mean contents in groups of soils from different regions in USSR were 3.07, 0.62, 0.92, 9.61, 0.81, and 2.5 mg kg-'. The average total content of I in the plough layers of soils of the European USSR calculated from all the available data is reported by Zyrin and Z b o r i s h c h ~ kto~ be ~ ~2.65 mg kg-'. The I content of samples from 19 series constituting various soil types in Spain ranges from 0.40-52.0 mg kg-', some 50% of the samples containing less than 3 mg kg-'. Calcareous rocks generally contain more I than siliceous rocks, and clay soils, mean 2.88 mg kg-', are richer than sandy soils, mean 1.37 mg kg-'.694 The mobility of l3II added to meadow and ploughed soils has been studied by Prister et al.695 A rapid volatilization of I was observed in the initial phase as well as considerable leaching but the strength of bonding of I with soil increased with the passage of time. Chilean Iodine Educational Bureau, 'Geochemistry of Iodine. Bibliography 1825-1 954', Chilean Iodine Educational Bureau, London, 1956, 150 pp. by3 N. G . Zyrin, and Yu. N. Zborishchuk, Sou. Soil Sci., 1975, (7), 558. h94 R. Gallego and S. Oliver, A n . Edufol. Fisiol. Veg., 1959, 18, 207. 6yJ B. S. Prister, T. A. Grigor'yeva, V. M. Perevezentsev, F. A. Tikhornirov, V. G . Sal'nikov, I. M. Ternovskaya, and T. T. Karaban, Sou. Soil Sci., 1977. (91, 3 16. 6y2

188

Environmental Chemistry

Aluminium and iron oxides and organic matter are the soil components most but their effectiveness is influenced by effective in sorbing iodine from pH. The I contents of 700 humus topsoils from Norway were found to decrease with increasing distance from the sea,674a finding of several other workers.6Y1 The results of an investigation into I in the UK environment, with particular reference to agriculture, has been published by Whitehead.6y7 Iodine is essential to the growth of animals. The healthy human adult body contains a total of 15-20 mg I, of which 70-80% is present in the thyroid gland and so far as is known the entire functional significance of I is accounted for by its presence in the thyroid hormones. A deficiency of I causes goitre in humans and this has been found to occur in areas where soil I contents are low. Iodine deficiency has not been encountered in plants but recently a disease of rice plants, 'Akagare disease', has been identified as due to an excess of iodine.698Both soils and affected plants have high I contents and it was concluded that the cause of the disease is induced by excessive absorption of solubilized iodine when the soil has been strongly reduced.

17 Arsenic, Selenium, Antimony, and Bismuth Arsenic occurs in various mineral forms, principally as Arsenic.-Geochemistry. arsenides in sulphide minerals and as arsenates. In the latter form its crystal chemistry is similar to that of phosphates, vanadates, silicates, or sulphates. The most common mineral is arsenopyrite, FeAsS. Arsenic can replace Si4+,A13+,Fe3+, and Ti4+ in rock-forming minerals. Other forms in which it can occur include arsenites, oxides, and alloys. The average contents of igneous rocks is 1.5 mg As kg-I with average contents for basaltic, gabbroic, and granitic rocks of 1.5, 1.4, and 1.5 mg As kg-', respectively. Of sedimentary rock contents that of shales is considerably higher, at about 13 mg As kg-', than those of sandstone and carbonates with 1 mg As kg-'.69y Phosphate rocks, important in a soil context because of their use as fertilizers, have an average content of 21 mg As kg-' derived from over 200 samples world wide.700The As content of fertilizer materials has recently been surveyed. '01 Weathering and Mobility. Little precise information is available on the weathering behaviour of arsenic in rocks and minerals. The oxides As,O,. and As,O, are water-soluble but the sulphides, particularly As2S3,are relatively insoluble.699In the weathering of sulphides, arsenic can be oxidized to arsenite and arsenate, and arsenite has been ascribed a half-life in soils of 6.5 k 0.4 years.7o2Conversion of arsenite to arsenate can occur in alkaline soil conditions and under the influence of

D.C. Whitehead, J . Soil Sci., 1978, 29, 88. D. C. Whitehead, J. Appl. Ecol., 1979, 16, 269. M. Tanno, T. Yamarnori, M. Inoue, and K. Yuita, Bull. Toyama. Agric. Exp. Stn., 1977, 8, 55. hYY K. H. Wedepohl (ed.),'Handbook of Geochemistry', 11-3/33, Springer-Verlag, Berlin. loo T. H. Tremearne and K. D. Jacob, in 'Arsenic in Natural Phosphates and Fertilizers', US Dept. Agric. Tech. Bull. No. 781, I94 1. '01 N. Senesi, M. Polemio, and L. Lorusso, Commun. Soil Sci. Plant Anal., 1979, 10, 1109. '** P. M. Tammer and M. M. de Lint, Neth.1. Agric. Sci., 1969, 17, 128. 696

The Elemental Constituents of Soils

189

ferric oxide.703 With the exception of the alkali-metal arsenates, most metal arsenates are poorly soluble. Much work has been done, with agricultural objectives, on the adsorption of arsenite and arsenate by soils. The adsorption of arsenite is influenced by the soil contents of sesquioxides, clay,7o4exchangeable The adsorption of arsenate calcium and magnesium and by the pH of the s0il.703~705 by soils resembles that of phosphate and the close association of adsorbed arsenate with Fe minerals, such as goethite, has been demonstrated by electron microprobe analysis.250It is strongly adsorbed both by hydrated Fe and A1 and by amorphous Fe and A1 components of soils.7o7Arsenic mobilized by the weathering of rocks and minerals is thus readily fixed and accumulated in clays and in iron and aluminium oxides in soils.

Soil Contents. Soils are enriched in arsenic relative to igneous rocks. The average arsenic contents for 1193 soils, calculated from the recent literature and quoted in Table 36, is 11.3 mg kg-', compared with the average igneous rock content of only 1.5 mg kg-'. The origin or arsenic in soils is considered to be mainly geological708 although industrial processes can make a contribution. For example the burning of coal, containing 0.53 to 1.04 kg As ton-', in an aluminium plant produced a local Table 36 Arsenic soil contents (mg As kg-I) Soils Range 11 surface soils, USA 3-14.1 0.1-42 195 profile soils, USA 3.1-13.3 9 subsurface soils, USA 0.4-2.8 23 soils, Israel, 8 profiles Trace-7.9 25 soils, Nova Scotia 24 soils, USA 6 1 soils, New Brunswick, 13 profiles <5-40 37 soils, USA 0-4 1 1.1-15.3 5 soils, USA 0.42-1.72 8 soils, Ontario 207 topsoils, Ontario 1.1-16.7 260 topsoils, Wales 3-194 228 subsoils, Wales < 1-46 0.1-40 10 surface soils, Scotland 90 soils, Canada, 26 profiles 1-20 1193 Soils Overall Mean 11.3 mg As kg-I

Mean 8.2 7.7 7.7 1.3 1 4.94 5.83 8.6 13 6.96 1.09 6.27 20 15 8.37 5.2

Ref. a b 717 c

d 7 26 25 2 728 e 525

f

g g 69

h

a J. S. Jones and M. N. Hatch, Soil Sci., 1937, 44, 37; K. T. Williams and R. R. Whitestone, U S Dept. Agric. Tech. Bull., 1940, No. 732, 20 pp; 'S. Ravikovitch, M. Margolin, and J. Navrot, Soil Sci., 1961, 92, 85; * R . F. Bishop and D. Chisholm, Can. J. Soil Sci., 1962, 42, 77; e J . R. Melton, W. L. Hoover, J. L. Ayers, and P. A. Howard, Soil Sci. SOC.Am. Proc., 1973, 37, 558; 'R. Frank, K. Ishida, and P. Suda, Can. J. Soil Sci., 1976, 56, 181; ". I. Bradley, C. C. Rudeforth, and C. Wilkins, J . Soil Sci., 1978, 29, 258; J. A. McKeague, J. G . Desjardins, and M. S . Wolynetz, Agri. Canada, Ottawa, 1979, LRRI Publ. 21

S. G. Misra and R. C. Tiwari, Indian J. Appl. Chem., 1963,26, 117. D. K. Sundd, Indian J . Appl. Chem., 1966, 29, 23. ' 0 5 S. G. Misra and R. C. Tiwari, Soil Sci. Plant Nutr. 1963,9, 2 16. K. Holobrady, J. Galba, and E. Chrenekova, Pol'nohaspodarstuo, 1969, 15, 956. lo' L. W. Jacobs, J. K. Syers, and D. R. Keeney, Proc. Soil Sci. SOC.Am., 1970, 34,750. J . Lig and E. Steinnes, Geoderma, 1978, 20, 3.

'03

lo4

190

Environmental Chemistry

fall-out of 41.4 kg As km-* yr-', which is equivalent to 232 mg As kg-' in the t.op~oil.~O~ The distribution of arsenic, and other elements from foundry smoke has been shown, however, to be confined to A horizons.710 The use of arsenic contents of soils as indicators of mineralization and as an aid 7 1 2 and the exceptionally high to geochemical prospecting has been studied,711* contents in Douglas fir have been used as a guide to precious and base metal 714

Soil contents of arsenic may be profoundly affected by arsenical compounds such as lead arsenate, used as fungicides and pesticides especially in orchards. Many early workers demonstrated greatly enhanced orchard soil contents of arsenic. O v e ~ l e y for , ~ ~example, ~ quotes orchard soil contents of 366-732 mg kg-I. These residues from the use of arsenicals have long been recognized as stable and persistent in soils716-719 and of sufficient magnitude to be toxic to soft fruit and vegetable crops.72oTotal arsenic contents of >50 mg kg-I were regarded as potentially toxic to susceptible plants by McPhee et al.721who also compared 25 Canadian non-orchard and orchard soils and found a mean content of 4.94 mg kg-I for the former and 61.95 mg kg-I for the latter. The use of methane-arsonate herbicide also affected soil contents.722Much of the arsenic remains in the upper 30 cm associated with the clay fraction and aluminium. The determination and distribution of toxic levels of arsenic in soils have been discussed by Arnott and Leaf723who suggest that -3000 mg As kg-' in soil is a level that can be used for phytotoxic purposes. The toxicity of As to biological systems has been Improved growth of chickens and pigs (see ref. 822) fed with arsenic has also been noted, although the effect may be that of toxicity to parasites. Plant uptake and phytotoxicity has recently been well-studied by a number of authors 726--731 with special regard to the modifying influences of soil concomitants, such as phosphorus,

E. Hluchan, M. Jenik, and M. Sedlak, Cesk. Hyg., 1968, 13, 591. H. J . Roesler, P. Beuge, and E. Mueller, Bergakademie, 1969, 21, 386. 'I1 J. R. Merefield, Geol. Mag.. 1973, 110, 165. P. Colbourn, B. J. Alloway, and I. Thornton. Sci. Total Environ., 1975,4, 359. 7 1 3 H. V. Warren, R. E. Delavault, and J. Barakso, Econ. Geol., 1964, 59, 1381. 7 1 4 H. V. Warren, R . E. Delavault. and J. Barakso, Can. Min. Mefall. Bull.. 1968, I . "' F. L. Overley, Wash. Agr. Exp. Stn. Bull., 1950, 5 14. 7 1 6 P. L. Gile, J . Agric. Res., 1936, 52, 477. 7 ' 7 J. S. Jones and M. B. Hatch, Soil Sci., 1945, 60, 217. 7 1 8 L. Wiklander and L. Fredriksson, Acta Agric. Suec., 1946, I, 345. 7 1 9 R. E. Hess and R. W. Blanchar, J . Soil Sci. SOC. Am., 1971,40, 847. 720 L. C. Vincent, Wash. Agr. Exp. Sln. Bull., 1944,437. 7 2 1 A. W. McPhee, D. Chisholm, and C. R. MacEachern, Can. J . SoilSci.. 1970, 40, 59. 7 2 2 L. R. Johnson and A. E. Hiltbold, Soil Sci. SOC. Am. Proc., 1969,33,279. 7 2 3 J . T. Arnott and A. L. Leaf, Weeds, 1967, 15, 121. 724 M. Covello, Farmaco Ed. Prat., 1960, 15. 345. 72J G. Schoenhard and W. Koenig, Z . Pflanzenkr. P'anzenschutz., 1975,82,329. 726 J. R. Miles, J. Agric. Food. Chem., 1968, 16, 620. 727 L. W. Jacobs, D. R. Keeney, and L. M. Walsh, Agron. J., 1970,62, 588. 728 E. A. Woolson, J. H. Axley, and P. C. Kearney, Soil Sci. SOC.Am. Proc., 197 I , 35,938. lZyE. Chrenekova and K. Holobrady, Sci. Agr. Bohemoslozi., 1972, 4. 87. ''O R. N. Carrow, P. E. Rieke. and B. G. Ellis, Soil Sci. SOC.Am. Proc., 1975, 39, 1121. 7 3 1 T. Hara, Y. Sonoda, and I. Iwai, Soil Sci. Plant Nutr.. 1977, 23. 253. 709

710

191

The Elemental Constituents of Soils

The potentially toxic arsenic which inhibit the toxic effects of As on levels in sludges from tannery works applied to agricultural soils736has been noted. The occurrence and distribution of As in plants and soils has recently been con~ i d e r e as d ~has ~ ~the choice of soil extractants for As.738

Selenium.-Geochernistly. Selenium, like arsenic, is closely related in its occurrence in igneous rocks to that of sulphur, which it can replace in sulphides. Selenides and selenites are also found but selenate is rare. The average contents of igneous rocks (of the USSR) is given by S i n d e e ~ as a ~0.14 ~ ~ mg Se kg-'. Sulphur to selenium ratios for rocks and sediments are shown in Table 37.740The S :Se ratio for the lithosphere is about 6000, and using this ratio the average Se content in igneous rocks is calculated to be 0.05 mg kg-', (Table 37). The Se content of shales is considerably higher than most other materials. The ability of Se to enter the molybdenite crystal lattice is relevant to the occurrence together of high Se and Mo contents in some soils.741Molybdenites may contain up to 240 mg Se kg-'.742-744A significant contribution to the Se content of sediments and soils is probably made by volcanic action. Contents of Se in the range 20-1040 mg kg-' have been found in volcanic The As:Se ratio in the lithosphere has been quoted as 35 IE5 and the ratio for soils, derived from Tables 36 and 38 is 28.2. Ratios of 2.5 and 7 have been reported by L i g and Steinnes708who suggest, for different areas of Norway, that sources other than geological, contribute to the Se content of soils and sediments, whereas for As weathered geological materials are the main contributors. An annotated bibliography of the geology of Se, 1958-1974, is available.746The relation of the geochemistry of Se to its occurrence in soils has 753

Table 37 Se contents of geological materials mg Se kg-' Igneous rocks Shales Sandstones Carbonates Deep sea sediments

0.05*

0.6 0.05 0.08 0.17

* Calculated from average S contents and a S : Se ratio of 6000, ref.

S :Se ratio 6000 4000 4800 15 000 7700 740

C. B. Rumberg, R. E. Engel, and W. F. Meggitt, Agron J., 1960. 52,452. E. A. Woolson, J . Sci. Food. Agric., 1972, 23, 1477. 734 D. R. Steevens, L. M. Walsh, and D. R. Keeney, J . Eni1ii-m. Quai., 1972, 1, 301. 7 3 5 E. A. Woolson, J. H. Axley, and P. C . Kearney, Soil Sci. SOC. Am. Proc., 1973, 37, 254. K. Maiwald, Forsch. Dienst., 1940, 10, 236. 7 3 7 L. M. Walsh, M. E. Sumner, and D. R. Keeney, Environ. Healfh Perspect., 1977, 19,67. 7 3 8 S. E. Johnston and W. M. Barnard, J. Soil Sci. SOC. Am.. 1979, 43, 304. 719 N. D. Sindeeva, 'Mineralogy and Types of Deposit of Selenium and Tellurium', Engl. Trans]. E. Ingerson, Interscience, N.Y. 1964. 740 K. K. Turekian and K. H. Wedepohl. Bull. Geol. SOC. Am., 1961,72, 175. 7 4 1 J. S. Webb, 1. Thornton, and W. K. Fletcher, Nature (London). 1966, 211, 327. 7 4 2 N. A. ChrusEov, V. G. Kruglova, and V. M. Pensionerova, Miner. Rohsfofl., 1960. 1,86. 743 G. Tischendof, Freiberg. Forschungsh. C, 1965, 186, 26 1. 744 M. KvaEek and Z . TrdliEka, Acta Unic. Carol. Geol., 1970, 2, 69. 745 B. I. Srebrodol'skiy and V. D. Sidelnikova, Geochemisfry, 1970, 8, 803. 746 C. A. Gent, U S Geol. Surv. Bull., 1976, No. 1419.

732

733

192

Environmental Chemistry

been reviewed (see ref. 798) and the importance of iron in the geochemistry of Se discussed (see ref. 799).

Weathering and Mobiliry. In the process of weathering, sulphides can be oxidized to sulphates which are readily leached from soils. Selenium on the other hand is oxidized in the weathering of sulphides to selenite and only exceptionally, in conditions of very high oxidation potential, to selenate. The predominant form of Se in soils is probably selenite, although a small fraction of the total may be present as selenate produced by biological oxidation.747Oxidation to selenate is more likely to occur in alkaline and neutral soils 74R and although alkali and alkaline-earth selenites are relatively soluble, ferric selenites and the compounds formed with basic iron hydroxides are not.749Selenium is therefore immobilized in inorganic soils by the iron hydroxides,750possibly as a basic ferric selenite.75'The retention of selenite by soils may also, in part, be due to adsorption by aluminium hydroxide752and by soil ~ l a y s and ~ ~this~ is3 consistent ~ ~ ~ with the maximal leaching of selenium occurring in sandy soi1s.753*755 Selenate is not so easily immobilized by iron hydroxides and is therefore more readily leached.748In highly organic soils Se is present in combination with organic matter747and, in this form, leaching is minima1.753v755 As a consequence of their contrasting behaviour during the processes of weathering and in their mobility, Se is strongly differentiated from sulphur in its distribution and is accumulated in soils relative to sulphur in the weathering of s~lphides.~~~ Soil Contents. Selenium is accumulated in soils relative to its abundance in rocks. The figures in Table 38, quoted from the recent literature, show that the average contents for Se in 1623 soils is 0.41 mg kg-' with an overall range of 0.03-2.0 mg kg-'. This average is 8 times that quoted in Table 37 for igneous rocks. The distribution of Se in soils is primarily a function of their parent and contents are likely to be low in soils derived from granites, sandstones, rhyolites, mica schist, and non-volcanic greywackes which are themselves low. On the other hand higher contents can be anticipated in soils derived from andesitic, basaltic, and argillaceous materials. Topsoils are enriched in Se, largely on account of their higher organic matter content, relative to s ~ b s o i l s . ' ~ ~ ~ ~ ~ Soils with very high Se contents, which have given rise to problems of toxicity, occur in many parts of the world. They are usually alkaline or neutral in nature and found in areas of low rainfall. In most cases the high Se contents are derived from A. A. Hamdy and G. Gissel-Nielsen, Res. Establishment Rim. Report, 1976, No. 349. 13 pp. 9. Bisbjerg, Res. Establishment Risn Report, 1972, No. 200, 148 pp. 749 E. E. Cary, G . A. Wieczorek, and W. H. Allaway, Soil Sci. SOC.Am. Proc., 1967, 31,21. 750 E. E. Cary and G. Gissel-Nielsen, Soil Sci. SOC.Am. Proc., 1973, 37, 590. 7 5 ' H. G. Geering, E. E. Cary, L. H. P. Jones, and W. H. Allaway, Soil. Sci. SOC. Am. Proc., 1968, 32, 35. 7J2 V . I. Plotnikov, Kuss. J . Inorg. Chem. (Engl. Transl.), 1960, 5, 351. 753 G. 9. Jones and G. B. Belling, Aust. J . Agric. Res., 1967, 18, 733. 754 N. Wells, N . Z . J . Sci., 1967, 10, 142. 752 H. Gissel-Nielsen and A. A. Hamdy, Z . PJanzenernaehr. Bodenkde., 1977, 140, 193. 756 F. Leutwein and R. Starke, Geologie, 1957,6, 349. 757 G. P. Dubikovskii and V. N. Lebedev,Agrokhimiya., 1973, 5 , 113. 747

748

193

The Elemental Constituents of Soils Table 38 Selenium soil contents (mg Se kg-I) Soils Range Mean Ref: 7 soils, Denmark a 0.1-1.5 0.4 8 soils, USA 0.06-0.62 0.3 749 62 soils, New Zealand 0.60 754 18 soils, India 0.1424.678 0.375 b 24 soils, Sweden 0.165-0.976 0.39 778 1 1 soils (grassland), Denmark 0.21-1.44 0.57 748 1140 topsoils, USA 0.40 C 106 soils, India d 0.158-0.7 10 0.4 1 8 soils, Canada 0.53-1.43 0.96 525 10 soils, Canada 0.197-0.744 0.438 18 56 soils, Scotland 0.1 1-1.59 0.69 e 114 topsoils, England and Wales 0.2-1.8 (median 0.6) 299* 173 soils, Canada, 53 profiles 0.03-2 0.2 1577 Soils Overall Mean 0.40 mg kg - I

s

* Not included in Mean B. Gregers-Hansen, Trans. 8th Int. Congr. Soil Sci. Publ. House Acad. Roumania, Bucharest, 1964,

3, 63; b C . A. Pate1 and B. V. Mehta, Indian J . Agric. Sci., 1970, 40, 389; “Geochemical Survey Missouri, 6th Open File Report, 1972; d S . G. Misra and N. Tripathi, Indian J . Agric. Sci., 1972, 42, 182; A. M. Ure and M. L. Berrow, unpublished: f J. A. McKeague and M. S . Wolynetz. Geoderma. 1980,24,299

the weathering of seleniferous sedimentary materials, especially shales. 748 The ability of soil organic matter to immobilize soluble Se species is well illustrated by the Se-toxic soils of Ireland where Se, carried by drainage water from the 7 5 9 The weathering of pyritiferous shales, is trapped in organic-rich highest soil contents of Se, 1200 mg kg-I, have been reported from these regions of Ireland. 760 Soil contents may be enhanced to a limited extent by fertilizers and soil additives, of which the most important are the phosphate fertilizer^."'^^^^+^^^ Aerial contributions, from from the burning of solid wastes and petroleum and from the enhanced Se contents of marine aerosols765-766 may also be factors. and from soils during drying747have Losses of selenium from soil been studied. The production of volatile selenium compounds by several soil and by microbial action have also been reported.769

T. Walsh, G. A. Fleming, R. O’Connor, and A. Sweeney, Nature (London), 195 I , 168, 88 1. T. Walsh and G. A. Fleming, Trans. 2nd and 4th Comm. I n l . Soc. Soil Sci., 1952, 2, 178. 760 G . A. Fleming, Soil Sci., 1962, 94, 28. 7 6 1 C. W. Robbins and D. L. Carter, Soil Sci. Soc. Am. Proc., 1971. 34, 506. G. Gissel-Nielsen, J . Agric. Food Chem., 197 1, 19, 564. 763 J. Kubota, E. E. Cary, and G. Gissel-Nielsen, in ‘Trace Substances in Environmental Health’, ed. D. D. Hemphill, Univ. ofMissouri, Columbia, 1975, Vol. 9. p. 123. 764 Y. Hashimoto, J. Y. Hwang, and S. Yanagisawa, Enuiron. Sci. Technol., 1970, 4, 157. 765 R. A. Duce, J. G. Quinn, C. E. Olney, S. R. Piotrowicz, B. J. Ray, and T. L. Wade, Science, 1972. 176, 161. 766 R. E. Van Grieken, T. B. Johansson, and J. W. Winchester, Rech. Atmos., 1974, 8 , 6 I I. 767 G . M. Abu-Erreisch, E. I. Whitehead, and 0. E. Olson, Soil Sci.. 1968, 106,415. 768 L. Barkes and R. W. Fleming, Bull. Environ. Contam. Toxicol., 1974, 12, 308. 76q J. W. Doran and M. Alexander, 2. PJanzenernaehr Bodenkde., 1976, 139.697. 758 75y

194

Environmental Chemistry

Selenium is essential for animal health,77"--773 deficiency producing white muscle disease in cattle, sheep, pigs, and poultry and infertility in sheep. Fodder variously reported as containing less than 0.1-0.2 mg Se kg-' can produce deficiency symptoms in farm animals.774-778Selenium responsive diseases of livestock have been r e ~ i e w e d . ~ ~ ~ - ~ ~ * The whole subject of the role of Se in the environment has been r e v i e ~ e d . ~ Shrift ~ ~ *786 ~ ~summarizes ~ - ~ ~ ~ some of the biological pathways of selenium in the environment including the metabolic conversion of selenate or selenite to selenide by bacteria, fungi, and higher plants, and the biological synthesis of seleno amino-acids and dimethylselenide. Selenium toxicity to animals is likely at fodder contents greater than 1 mg Se kg-'.748

Antimony.-Geochemistry. In its crystal chemistry and geochemistry Sb strongly resembles its neighbours, As and Bi, in the periodic table. It occurs in minerals as the element, as antimonides, sulphides, complex sulphides and oxides, its most common mineral being stibnite (Sb,S,). It can replace iron in rock-forming minerals and shows a preference for olivine and ilmenite. For basic rocks average Sb contents are probably about 0.1-0.2 mg kg-I and about 0.2 mg kg-I for intermediate and acidic rocks, with an overall average igneous rock content of approximately 0.2 mg kg-'. The antimony content of shales is variable, averaging some 1-2 mg kg-1.787 Soil Contents. A few early references to antimony contents exist7"~789 indicating ~~" soil contents of a few mg kg-l. The few recent reports include that of B ~ y l e , who found a range of 1-3 mg kg-I with an average content of 1.9 mg kg-' for Canadian (Yukon) soils. In 6 1 samples from 13 profiles sampled in non-mineralized areas of New Brunswick a range of < 1-4, mg Sb kg-I, mean 1.8 mg Sb kg-' has K . Schwartz and C. M. Foltz, J . Am. Chem. SOC.,1957, 79,3292. K. Schwartz and C. M. Foltz, J . Biol. Chem., 1958, 233, 245. '12 K. Schwartz, J. A. Stesney and C. M. Foltz, Metab. Clin. Exp., 1959, 8,88. 11' H. Dam and E. S~ndergaard,Experientia, 1957, 13,494. 114 J . E. Oldfield, J . R. Schubert, and 0. H. Muth, J . Agric. Food. Chem., 1963, 11, 388. '15 M. R. Gardiner and R. C. Gorman, Aust. J . Exp. Agric. Anim. Husb.. 1963, 3, 284. 176 W. H. Allaway and J . F. Hodgson,J. Anim. Sci., 1964, 11, 609. 11' W. J. Hartley, in 1st Int. Symp. on Se in Biomedicine, Oregon State University, 1966, ed. 0. H. Muth, AVI Publ. Co., Westport, Conn., USA., 1967. p. 79. 11' P. Lindberg and S. Bingefors, Acfa Agric. Scand.. 1970, 20, 133. '19 W. J . Hartley and A. B. Grant, Fed. Proc., 1961, 20,679. l h nJ. H. Watkinson. Trans. Comm. IV & V, Int. SOC.Soil Sci., 1962, ed. G . J. Neale, N.Z. Soil Bureau, Lower Hutt, 1963, p. 149. l R '0. H. Muth and W. H. Allaway, J . Am. Vet. Med. Assoc., 1963, 142. 1379. lHZ K . L. Blaxter. Rr. J . Nufr., 1963. 17. 105. 183 I. Rosenfeld and 0. A. Beath, in 'Selenium - Geobotany, Biochemistry Toxicity and Nutrition', Academic Press. N.Y.. 1964. lR4M. S. Anderson. H. W. Lakin, K . C. Beeson, F. F. Smith, and E. Thacker, US Dept. Agric. Handbook, 196I , No. 200,65 pp. lR5H. W. Lakin, in 'Trace Elements in the Environment'. ed. E. L. Kothny. 1973, p. 96. lR6A . Shrift. Nature (London), 1964. 201, 1304. lR1K . H. Wedepohl (ed.), 'Handbook of Geochemistry', II-4/5 1, Springer-Verlag, Berlin. 188 F. N. Ward and H. W. Lakin, Anal. Chem.. 1954, 26, 1168. ''' H. E. Hawkes, U S Geol. S u n 3 .Bull.. 1954. No. 1000-B. 5 I . 19" R. W. Boyle, Geol. Surzl. Can. Bull., 1965, No. 1 1 I .

'lo

11'

The Elemental Constituents of Soils

195

been reported,252whereas a range of 0.66-2.1 1 mg kg-', mean 1.16 mg kg-' has been reported in 8 samples from a 'muck' soil from Holland Marsh, Ontario.525 Anomalous Sb contents averaging 84.8 mg kg-' in UK soils791and two brown earths containing 2000 and 1500 mg kg-l have been reported.792More recent values mg Sb kg-' with a mean include 4 normal UK topsoils ranging from 1.1-8.6 content of 4.6 mg kg-' (Cawse, personal commun. 1973) and, for ten Scottish topsoils on different parent materials, contents ranging from 0.29-1.3 mg kg-' with a mean of 0.64 mg kg-'.69 Antimony contents in 14 soils from Bulgaria, determined by neutron activation analysis, ranged from 0.82-2.32 mg Sb kg-I, mean 1.32 mg Sb kg-'.504 Tentatively, a value of about 1 mg kg -'can therefore be assigned as the average soil content. Antimony, like arsenic, would appear to be enriched in soils relative to the content in igneous rocks. Radioactive lz5Sb(half-life 2.7 years) from fall-out has been determined in soils.793

Bismuth.-Geochemistry. Geochemically Bi resembles As and Sb, occurring mainly in sulphide deposits. In its electronic structure Bi3+is similar to Pb2+and Bi often occurs in association with lead, in for example, galena. The ionic radius of Bi3+ is close to that of Y2+ and the rare earth elements, and some geochemical The average contents in basic and association of Bi and Y has been acid igneous rocks have been reported to be 0.15 mg Bi kg-' and 0.18 mg Bi kg-', re~pectively,~ the ~ ~range . ~ ~ ~ of contents being considerable. The most recent estimate of the crustal abundance of Bi is 0.17 mg kg-'.753796In common silicate minerals Bi is usually present at levels of < 1 mg kg-', but Bi minerals have been found in granite pegmatite~."~The most common bismuth minerals are bismuthinite (Bi2S3) and bismite (Bi203). Bismuth is enriched in organic sedimentary materials such as coal and bitumen.797

Soil Contents. Little appears to have been published recently on Bi contents of soils. In a study of 10 Scottish soils derived from different parent material^,^^ however, a range of 0.13-0.42 mg Bi kg-I with an average of 0.23 mg Bi kg-', was found. A range of <1--1.52 mg Bi kg-', mean 1.0 mg Bi k g ' , has also been reported in 8 samples from a 'muck' soil from Holland Marsh, Ontario.525These levels are of the same order as those for igneous rocks. The highest Bi content reported in soils is 13 mg kg-' in a mangrove soil from M a d a g a ~ c a r . ~ ' ~

R. E. Stanton and A. J. McDonald, Anal-vsf (London), 1962,87, 299. D. J. Nicholas, Anal. Chim. Acta, 1971, 5 5 , 59. 793 A. Kasai and Y. Yanase, Radioisotopes, Tokyo, 1965, 14, 518. 7y4 K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/83, Springer-Verlag, Berlin. 7y3 R. R. Brooks, L. H. Ahrens, and S . R. Taylor, Geochim. Cosmochim. Acta, 1960, 18, 162. 79b R. R. Brooks and L. H. Ahrens, Geochim. Cosmochim. Acta, 1961,23, 100. 19' M. I. Brandenstein, J. Schroll, and E. Schroll, Tschermaks. Mineral. Petrogr. Mitt., 1960, 7, 260. 798 H. W. Lakin and D. F. Davidson, 1 s t Int. Symp. Selenium in Biomedicine, Oregon State Univ., ed. 0. H. Muth, AVI Publ. Corp., Westport, USA, 1967, p. 27. 799 J. H. Howard, Geochim. Cosmochim.Acta, 1977,41, 1665. 79'

7y2

Environmental Chemistry

196 18 Thorium and Uranium

Geochemistry.-Reviews of the geochemistry of these elements have included The organic geochemistry of accounts for Th,800for U,Roland for Th and U.8027803 U has also been comprehensively d i s c ~ s s e d . ' ~ ~ ~ ~ ~ ~ Uranium occurs widely in trace concentration in major minerals such as quartz and feldspar (0.1-10 mg kg-') and in high concentrations in some uraniferous accessory minerals. The most abundant uranium mineral, an oxide mineral, is uraninite (pitchblende). Whereas in basic igneous rocks the uranium is uniformly distributed, in granitic rocks much of it is in small crystals of accessory minerals. Uranium is enriched in granite and syenite pegmatites. The uranium contents of various igneous and sedimentary rocks have been summarized.668 Thorium is also dispersed in a variety of minerals and occurs as a major constituent only in accessory minerals. Thorium substitutes for Zr in zirconium minerals. Both Th and U contents increase with increasing silica contents in igneous rocks and, in a wide range of these the K :Th ratio is reasonably constant at lo3 and the K : U ratio at about 104.807The average T h : U ratio in igneous rocks has an approximately constant value of 3.5-4.800

-

Weathering and Mobility.-In igneous rocks U is usually present in quadrivalent form but is readily oxidized, by weathering processes in surficial materials, to the sexavalent (uranyl) form, which is relatively soluble compared with the corresponding Th form. This gives rise to differentiation between Th and U in sedimentary rocks and in soils. Thorium accumulates in residual soils and weathered rocks such as bauxiteRo8and also in the less soluble (resistate) materials ~ ~ ~ ~on~ the ' ~ other hand is depleted in weathered and in residual ~ l a y s . Uranium granites by the loss of mobilized material.811This differentiation in part accounts for the departure in sedimentary materials of the Th :U ratio from the constant value 3.5-4 obtained in igneous rocks. Uranium, immobilized by phosphate in the presence of Ca, Pb, and C U , ~ ' *is widespread in clays and carbonate rocks and reaches high concentrations (> 100 mg kg-I) in black, bituminous shales of marine origin, perhaps owing to the formation of stable complexes with chitin in shells and fungi.'86 The ability of uranium to be concentrated by organic matter,ls6 unlike thorK. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/90. Springer-Verlag, Berlin. K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-5/92, Springer-Verlag, Berlin. xo2 J . A. S. Adams, J. K. Osmond, and J. J. W. Rogers, Phq's. Chem. Eurlh, 1959, 3, 298. '03 I. J. Dybek, 'Clausthaler Hefte Lagerstattenkunde und Geochemie der Mineralogischen Rohstaffe', 1962, Vol. I , 163 pp. '04 1. A. Breger and M. Deul, US Geol. Surv. ProJ Pup., 1956, 300, 505. ' 0 5 P. J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130. 238. '06 0. P. Meelu and N. S. Randhawa J . Indian SOC.Soil Sci., 1973, 21, 235. '07 K . S. Heier and J. J. W. Rogers, Geochim. Cosmochim. Actu, 1963, 27. 137. 808 J. A. S. Adams and K. A. Richardson, Econ. Geol., 1960,55, 1653. J. A. S. Adams and C. E. Weaver, Bull. A m . Assoc. Pelrol. Geol., 1958.42, 381. 'lo R. Pliler and J. A. S. Adams, Geochim. Cosmochim. Actu, 1962,26, 11 15. K. A. Richardson, in 'The Natural Radiation Environment, ed. J . A. S. Adams, and W. M. Lowder, Chicago Univ. Press., Chicago, USA, 1964, p. 47. ' I 2 M. S. Lambert and D. S . Nikolaev, Dokl. Akud. Nuuk. US S R , 1962, 142, 681. 'O0

Rol

The Elemental Constituents of Soils

197

iumX14, 8 15

contributes further to the differentiation of U and Th in organic rich sediments, peats, and soils. Soil Contents.-Thorium. Despite the low mobility of Th compared with U, movement in soil from the A , horizons to illuvial horizons occursxt6 but concentrations of mobile T h are Some evidence of the association of Th with humus in soils has also been reported,'l* as has the accumulation of Th with sesquioxide.xly The contents of Th in 115 soils, summarized in Table 39, have a mean of 14 mg kg-' and a range of 0.5-72 mg Th kg-'. Ranges of T h contents of 9-1 1821 and 7-14.7 mg kg-lXo6for USA soils and mean values for Estonian bog soils ranging from 0.06-2.8 mg kg-' 823 have been reported. Bowen 74 quotes a range of 1-35 mg Th kg-I and a median soil content of 9 mg Th kg-I. In addition to the soils in Table 39, Robtsov820also reports soil profile contents for regions of high y-radiation in which surface and near surface Th contents exceeded 500 mg kg-'.

Table 39 Thorium soil contents (mg Th kg-I) Soils 19 soils (compilation) 4 soils, Poland 17 profile soils, USSR 9 soils, Brazil 40 soils, Bulgaria 4 soils, C a n a d a 10 soils, Scotland 12 soils, USA 115 Soils

Range

Mean Re$ 11.5 93 10.2 a 31.8 819 19.0 70 9.74 50 4 8.0 b 11.2 69 9.1 805 Overall M e a n 14.0 mg Th kg-I 0.5-56 8.6-12 13-72 3.3-35 3.6-17.8 4.2-14 4.1-18 2-13

M. Gorski and S. Zmysowska, Post. Nauk., 1956, 3, 1 I ;* R. D. Koons and P. A. Helmke, Soil Sci. SOC.Am. J . , 1978,42,237

'I3

'I4

K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-2/17, Springer-Verlag, Berlin. V. I. Baranova and N. A. Titaeva, Geokhimiya, 1961, No. 2, 110. V. I. Baranova, N. G . Morozova, K. G. Kunaskeva, and G. 1. Grigorev, Pochuovedenie, 1963, No. 8, 11.

'"V.

I . Baranova, N. G. Morozova, and K. G. Kunasheva, Radioaktiv. Pochv. Metodv Opr. Akad. Nauk, S S S R , 1966, 195. Yu. V. Alekseev, Zap. Leningr. S'kz. Insl., 1967, No. 5, 105. 818 G. E. Pashneva, T. P. Slavnina, and V. V. Serebrennikov, Izv. Sib. Otd. Akad. Nauk S S S R , Ser. Biol-med. Nauk, 1965, I, 48. "'0. Talibudeen, Soils Fert., 1964, 27, 347. ''O D. M. Robtsov, Sou. Soil Sci., 1966, 290. R. 0. Hansen, Soil Sci., 1970, 110, 3 1. 8 2 2 Anon., Chem. Eng. News, 1966, 44, 48. 823 V. I. Baranov, N. G. Morozova, and K . G. Kunasheva, Pochvovede, 1971, No. 10, 112. National Research Council of Canada, 'Effects of Mercury in the Canadian Environment', N R C C Assoc. Comm. Sci. Crit. Environ. Qual. Report No. 16739, Ottawa, Canada, 1979.

Environmental Chemistry

198

Uranium. Although in granitic soils U is often largely in the resistate minerals such as zircon the interactions of uranium with organic material can have profound effects on its distribution in soils.'y4Uranium can accumulate in soils and peats near sites of U-mineralization as a result of mobilization and redeposition in association with organic matter.825It can be transported above pH 8 as fulvic acid complexes but is immobilized at lower pH by humic and fulvic acid fractions of peat.8263s27 Peaty soils in Ireland have been reported to contain up to 550 mg U kg-I, probably derived from drainage waters from uraniferous shales.828The accumulation of U in the illuvial horizons of some USSR dernopodzolic soils has also been noted.82YThe mobilization and fixation of U by aerobically decomposing plant material has been discussed. 128 The accumulation of U in soils can result from prolonged application of s ~ p e r p h o s p h a t e .The ~ ~ ~analytical methodology for U in soils has been considered by several w o r k e r ~ . ' ~ ~ Contents -'~~ of U in 283 soils are listed in Table 40, and further discussion of the distribution of U in soils and soil profiles has been made by several a ~ t h o r s .In~ ~a study ~ , ~ of ~ ~some 300 soils from Spain, Portugal, Australia, and Germany, contents seldom exceeded 4.2 mg U kg-'. This study also indicated that the U contents of A and B horizons of dystrophic cambisols were not elevated, even in regions of uranium mineralization, although adjacent rock deposits and gleyed soils showed enrichments with contents of up to 850 mg U kg-'.837A review of Th and U in soils and geological materials is available.838 Table 40 Uranium soil contents (mg U kg-I) Soils 10 soils, USSR 250 soils, USSR 9 soils, Brazil 10 soils, Scotland 4 soils, Canada 283 Soils

Range Mean Re5 0.9-5.8 2.5 93 0.8-3.6 2.1 829 1-3.6 2.3 70 4.0 69 1.2-14 1.25 u 0.76-2.1 Overall Mean 2.18 mg U kg-'

R. D. Koons and P. A. Heimke. Soil Sci. SOC.Am.J., 1978,42,237

G. Armands and S. Landergren. Int. Geol. Congr. Rep. 21 Sess., Norden. 1960. Pt. XV. 51. S. M. Manskaya, T. V . Drozdova. and M. P. Emelyanova. Geokhimiva, 1956. No. 4, 10. 827 N. A. Titaeva. Geakhimiya. 1967. No. 12, 1493. C. Williams and G. Brown, Geoderma, 1971,6, 223. 829 S. A. Tikhonov, Dokl. Akad. Nauk. Belarus, SSR.. 1963, 7. 405. M. J. Duggan, Water, Air Soil Pollut., 1980. 14,309. H. P. Rothbaum, D. A. McGaveston, T. Wall. A. E. Johnston, and G. E. G . Mattingly, J . Soil Sci., 1979, 30, 147. A. Szekely, Agrokem. Talajtan, 1960, 9,38 1. D. Purushottam, J . Sci. Indian Res. 1960, 19B,449. 8 3 4 E. S . Gladney, W. K. Hensley, and M. M. Minor, Anal. Chem., 1978,50,652. G . V. Gurskii and S. A. Tikhonov, Dokl. Akad. Nauk. B. S S R , 1966, 10, 763. 836 L. M. Moreira-Nordemann and G. Sieffermann, Soil Sci., 1979. 127. 275. "'H. W. Scharpenseei, F. Pietig, and E. Kruse. 2. Pflanzenernaehr. Bodenkde.. 1975, 138. 13 1. C. M. Bunker and C. A. Bush, US Geol. Surre-c.Prof: Pap., 1968, No. 600-8, 7 1. 826

199

The Elemental Constituents of Soils

No evidence exists for the biological essentiality of these elements, but there is evidence of the accumulation of U in plant material^"^-^^^ and of the uptake of Th843*844 as well as the stimulation of the growth of nitrifying bacteria by Th.84sA bibliography of the biological effects of Th is available.846The principal biological interest in these two elements lies in their radioactivity but an account of this would not be appropriate here. 19 Radionuclides

It would be inappropriate in this work to deal in depth with this specialized subject but a brief review of some recent literature on the occurrence of radionuclides in soils is presented below. Data on radionuclides in the environment, and in rocks and soils in particular, has recently been reviewed by B ~ w e and n ~ ~soil contents are summarized in Table 4 I from this source. The radioactivity of soils is mainly due to their contents of 40K and 87Rband the disintegration of U and Th. In addition to these natural sources an additional contribution is provided by fall-out of artificial radionuclides from nuclear explosions and by contamination from the industrial use of nuclear fission for electric power generation. The addition of potassic and phosphatic fertilizers, the latter often rich in U, may contribute annually to arable soils some 5.2 x l O I 4 Bq of 40K and 4.1 x lOI3 Bq of 238U.This contribution to radioactivity from fertilizer applications may often exceed that from fall-out from nuclear bomb te~ting.'~ Mean concentrations of naturally occurring radionuclides for New Zealand soils of 22.9 Bq kg-' for 226Ra,29 Bq kg-I for 232Th,and 370 Bq kg-' for 40K, have been

Table 41 Mean and (range) of radionuclide contents of soils? (expressed in terms of radioactivity) Natural radionuclide 14C 40 K *loPb 210Po 226Ra R7Rb 230Th 232Th 234

u

2 3 8 u

Soil content Bq kg-'** 4 (1.5-6) 440 (0.2-1200) (75-6300) (8-220) 30 (7-180) 140 (20-560) 100 (3700- 16 000) 37 (4-78) 26 (9-120) 24 (8- I 10)

Artificial radionuclide

** 1 Bq = 2.70 x lo-" Ci = 27.0 pCi. * Bq m * soil. of the Elements'. Academic Press, London, 1979. p. 205

'3'CS

Fe 54Mn 55

23XPU 2 3 Y t 240pu

241Pu 'OSr

Soil contenl Bq kg-I** 63 (18-90) 7 loo* 7.4 (0.007-0.0 7) (0.05- 1.4) 16 35 (20-55)

t H. J . M. Bowen. 'Environmental Chemistry

*'')0. P. Golikov, Fizio1.-Biokhim Oshovi Pidvishchennya Productivn. Rod.,

1963, 225. L. Raikov, M. Yanachkova, and M. lotov. Pochvozn. Agrokhim.. 1961. 1, 155. 8 4 1 V. V. Koval'skii and 1. E. Vorotnitskaya, Ukr. Biokhim. Zh.. 1966, 38, 419. w42 M. K. Nagpal, K. K. Nagpal, and A. K. Bhan, Curr. Sci., 1974. 43. 8. 843 V. 1. Baranov and K. G. Kunasheva, Tr. Biogeokhim. Lab. Akad. Nauk., S S S R , 1954. 10,94. 844 C. T. Horovitz, H. H. Schock, and L. A. Horovitz-Kisimova, Planf Soil, 1974. 40, 397. R 4 J S. P. Tandon. S. K. De, and R. C. Rastogi, Agrokem. Talajran, 1963. 12. 293. 846 E. Hutchinson, US A / . Energy Comm. Rep.. 1960, UR563.47 pp.

R40

200

Environmental Chemistry

reported.847The variability was found to be too great to allow any conclusions relating radioactivity and soil type to be drawn. Soil-profile studies in New Zealand have yielded ranges for 210Pbof 10-30 Bq kg-’ and for 226Raof 15-30 Bq kg-’ and the conclusion that 210Pbis accumulated in the surface layers.848 In size fractions from a weathered granite soil the Ra content was found to increase with decreasing particle size.849Data on radionuclides of K, Ra, and Th in USSR soils are given by Brendakov et who quote concentration ranges for Ra in upper layers of Caucasus soils of 2.6-16.7 x g Ra g-’ and 2.8-9.5 x g Ra g-I in soils from the Russian platform and Crimea. In a study of some 200 New Zealand soils the equilibrium between 238Uand 226Raand the Th :U ratio were found to be affected by the Fe content and these relationships depended on the soil parent material.851The forms of 226Rahave been studied in soil horizons with high concentrations of this nuclide852and the contents of Ra and Th in Armenian soils have been discussed.853 Carbon-14 has been used to establish soil-formation times and, by this method, the ages of chernozems from USSR have been put at between 8000 and 9000 years.854Other radio-carbon studies include references 855-85 7. The mobility of sodium and iodine in soils has been studied by monitoring added r a d i o - s ~ d i u m ~ ’ ~ and added r a d i o - i ~ d i n e . ~ ~ ~ Of the radionuclides produced by nuclear fission and contributed to soils as atmospheric fall-out, most attention has been paid to 90Sr and 13’Cs. An average value for 90Sr accumulated in Japanese paddy soils86oof 5220 MBq km-2 and a range of 3.7-13 Bq kg-’ in Hungarian soilss61have been quoted. Soil profile contents of 90Sr(and 210Pband 137Cs)sareconsidered by Kodaira et al.862and current evidence suggests that this nuclide is more mobile in the soil profile than I3’Cs. The removal of 90Sr from soils by leaching and by plant uptake and the affect of agricultural practices on this, are treated by Haghiri and hi me^.^^^ Uptake and accumulation by crops is reviewed by Arkhipov et a1.864

J . E. Dobbs and K. M. Matthews, N.Z. J. Sci., 1976, 19, 243. T. Baltakmens, N.Z. J . Sci., 1974, 17,435. 849 K. Megumi and T. Mamuro, J . Geophys. Res., 1974,79, 3357. 850 V. F. Brendakov, S. V. Iokhel’son, and V. N. Churkin, Sou. Soil Sci., 1967, (l), 31. 851 T. Baltakmens, N.Z. J . Sci., 1976, 19, 375. 8 5 2 A. I. Taskayev, V. Ya. Ovchenkov, and R. M. Aleksakhin, Sou. Soil Sci., 1978, (l), 45. 853 V. L. Ananyan and A. S . Avetisyan, Akad. Nauk. Armyan. SSR., 1971, 11,5. 8 5 4 E. V. Rubilin, M. G. Kozyreva, and A. I. Zubkov, Trans. 10th Int. Congr. Soil Sci. IV, 1974, Part 11, 347. 8 5 5 H. W. Scharpenseel and F. Pietig, Radiocarbon, 1971, 13, 189. J. D. Stout and B. J . O’Brien, N . Z . Soil Bur. Publ., 1973, No. 63 1, 12 pp. *” H. W. Scharpenseel, Trans. 10th Int. Congr. Soil Sci., 1974, Part VI, 315. A. Grauby and A. Saas, Trans. 10th Int. Congr. Soil Sci., 1974, Part X, 92. x 5 9 V. M. Prokhorov, A. B. Shchukin, 0. M. Kvetnaya, and P. Sh. Malkovich, Sou. Soil Sci.,1978, (6)’ 663. 860 K. Kawase and E. Yokoyama, Trans. 10th Int. Congress Soil Sci. 1974, Part 11, 195. E. Kalmar, Agrokem. Talajtan, 1974, 23, 35 1. 862 M. Kodaira, M. Kato, and M. Ishekawa, Radiosotopes, Tokyo, 1973,22, 33 I. F. Haghiri and F. L. Himes, Res. Bull. Ohio. Agric. Res. Dev. Center, Wooster, USA, 1974, No. 1072, 14pp. 864 N. P. Arkhipov, E. A. Fedorov, P. F. Bondar, R. Maleksakhin, G. N. Romanov, and L. T. Fevraleva, Pochuovedenie, 1974, 7,61. 847 848

The Elemental Constituents of Soils

20 1

The range of 137Csvalues found in cultivated and uncultivated watershed soils of USA865was 2070-5510 Bq m-*, with mean values for cultivated soils of 2780 Bq m-2 and for uncultivated soils of 3850 Bq m-2. The contents of 137Csin the reservoir sediments, into which these watersheds drained, were found to be 2.8-4.0 times the contents of the watershed soils866 but the bulk of the fall-out 137Csremained in the grass cover. The 137Csis readily sorbed by soils, soil clays, and peaty soils867-86y and the sorbed 137Csexceeds the exchange capacity of the soil, especially in vermiculite and clay loam soil.x6yN o fixation was observed, however, in montmorillonite or kaolinite. The effect of soil properties on the The accumulation of 137Csand 90Sr in crops is considered by Abbazov et sorption properties of 137Cscombined with its accumulation in surface organic litters71tend to confine the deposited 137Csto the upper layers of soil. Soils at Nagasaki, contaminated by the 1945 atomic bomb explosion, and investigated some 25 years later, still contained ten times as much 239Puas samples contaminated only by fall-out from subsequent nuclear test explosions.872Similar long-term studies of bomb-site soils have been made by Nyhan et al.873Although Pu disintegration products, Am and Cm, have been determined in fall-out collected on lichens,874 their presence in soils has not been reported. Addition studies, however, on Pu, Am, and Cm migration, extraction, and behaviour in soils have A correspondence has been shown been made and their uptake by plants between soil and barley contents of Pu.876 At soil contents (370 Bq g-I the plant/soil concentration factor increased suggesting either a concentration dependent change in availability or a plant toxic effect at higher concentrations. A report on the concentration of actinides in the food chain, including details of levels in soils and uptake into plants, has been 20 Organic Soils

Plant residues are added to the topsoil by the normal growth and decay of vegetation. Where conditions restrict or prevent the oxidation and decomposition of plant residues, these may accumulate and peat start to form. This normally happens when aeration of the surface soil is prevented by waterlogging and dead material may accumulate until the greater part of the soil is organic matter. Other factors

J. C. Ritchie and J. R. McHenry, J. Environ. Quai., 1978, 7,40. J. C. Ritchie, J. R. McHenry, and A. C. Gill, Ecology, 1974, 55, 887. K. Smierzchalska, Rocz. Nauk Roln., Ser. A . , 1973,99, 39. S. Csupa, Pol’nohaspodarstvo, 1974, 20, 1 14. 869 R. K. Schultz, R. Overstreet, and I. Barshad, Soil Sci., 1960, 189, 16. M. A. Abbazov, 1. D. Dergunov, and R. G. Mikulin, Sou. Soil Sci., 1978, ( I ) , 52. 8 7 1 L. Salmon, U.K. Atomic Energy Authority Res. Group Report., AERE-R4OI8, 1962,9 pp. 8 7 2 M. Sakanque and T. Tsuji, Nature (London), 1971. 234, 92. 8 7 1 J. W. Nyhan, F. R. Miera, jun., and R. E. Neher, J. Environ. Quai., 1976, 5,43 1 . 874 E. Holm and B. R. R. Person, Nature (London),1978, 273, 289. R. A. Bulman, Naturwissenschaflen, 1978, 65, 137. R. E. Wildung and T. R. Garland, J . Agric. Food. Chem., 1974, 22, 836. 865

866

*”

R. A. Bulman, National Radiological Protection Board, Report 44, 1976,48 pp.

202

Environmental Chemistry

that favour the development of peat are low temperature, high acidity, and nutrient deficiency, all of which reduce microbiological activity. Such organic soils, sometimes called peats or mucks, are defined as those containing 25% or more of organic matter. Peat deposits that have developed under the influence of ground water often reach depths of 10 metres or more and exhibit a complex and varied stratification. Where climate is the chief factor influencing bog development, deposits are on the whole less deep and seldom show marked horizon differentiation.878 The chemical composition of peat, particularly of the lower horizons, is influenced to some extent by the composition of the mineral substrate on which the peat is developed. Other sources of input are sea-spray, air-borne dust, and precipitation. The composition of peat is also influenced by the mineral content of the water associated with peat formation since this controls the type of plants involved. Plant communities associated with soils and waters rich in nutrients (eutrophic conditions) give rise to a type of peat different from that formed where conditions are acid and base deficient (oligotrophic conditions). Much work has been done on the chemical composition of peats, particularly on major element (Ca, Na, K, Mg, P, and N) composition and such analyses are reported, for example, in Memoirs of the Soil Survey of Great Britain, Scotland published by HMSO. Analyses of major elements in peat profiles have also been reported by Chapman 879 and by Stewart and Robertson.880 Approximate ranges and average contents of 27 elements in organic soils have been reported by Davis and Lucas.881Comparison of their typical average figures for organic soils with the median figures reported by Bowen74for mineral soils show, as might be anticipated, that organic soils are much richer in C and N but much poorer in Al, Si, Ti, Fe, Mn, Ba, K, and Na than mineral soils. Many trace elements are also lower in peats than in mineral soi1s.882*883 In a study of trace element distribution in Finnish peatsgg4it was found that the contents of Zn, Pb, Mn, Sr, Sn, and V were considerable in the surface horizons, minimal in the middle of the profile, and maximal in the underlying mineral soil. The trace element content within these profiles decreased as the thickness of the peat increased. Analyses of some deep peat profiles from Scotland have shown, however, than in certain lower layers, at depths of 100-600 cm, zones of accumulation of some trace elements occur where the content may be up to 100 times that in other horizons of the same profile.885Other studies of trace element distribution in peat profiles include those of Priemskaya,886T a n ~ k a n e n , ~ ~ ~

R. A. Robertson, Sci. Hortic., 1962163. 16.42. S. B. Chapman, J . Ecol., 1964, 52, 3 15. J . M. Stewart and R. A. Robertson, Proc. 3rd Int. Peat Congress, Quebec, Canada, Dept. of Energy, Mines and Resources and the Natl. Res. Council o f Canada, 1968, 190. J. F. Davis and R. E. Lucas, Dept. Soil Sciences, Agric. Expr. Stan. Michigan. State Univ., East Lansing, Michigan, Special Bull., No. 425, 1959, 156 pp. R82 M. Sillanpaa, Proc. 4th Int. Peat Congress I-IV, Helsinki, Int. Peat Society, Helsinki. 1972, p. 185. f183 M. Kurki, SUO,1975, 26, 93. n’4 M. Sillanpaa, Suo, 1975, 26, 83. 13’ R. L. Mitchell, Proc. Int. Peat Symp., Dublin, Section B3. 1954. A. E. Priemskaya, Pochvovedenie, 1969.4, 59. *” H. Tanskanen, Sua, 1972, 23.63. 878 f179

203

The Elemental Constituents of Soils

Kurki,883Casagrande and Erchull,sXRPakarinen and T o l ~ n e n , ~Rump ~ ~ . ~el~a/.,89' " Y l i r u ~ k a n e n ,and ~ ~ Largin ~ . ~ ~ ~et

21 Conclusion The total contents of elemental constituents in soils are summarized in Table 42, which presents the means and ranges for 68 elements compiled from data in the text ~ ~ also * ~ ~presented and in Tables 1-41. Values reported in earlier c o r n p i l a t i ~ n sare together with crustal average figures calculated by Taylor.75 Some elements, notably C, N, C1, Br, I, As, Se, and possibly Ag and Sn, are considerably richer in soils than in crustal rocks, but for most elements, including the rare earths, the average contents are similar to the crustal average values suggesting that most elements are largely retained during the breakdown and weathering of rocks to form soils. There appears to have been some overall loss, however, of Mg, Ca, and Na together with Co, Ni and Cu during soil formation, as suggested for the latter two elements by Ure et a1.'jY

Table 42 Total crustal rock and soil contents summarized. Means and (Ranges) in mg kg--I . Means in parentheses* are tentative values Atomic Number 3 Li 4 Be 5 B 6 C 7 N 8 0 9 F 11 Na 12 Mg 13 A1 14 Si 15 P 16 S 17 C1 18 K 20 Ca 21 s c 22 Ti 23 V 24 Cr

Crustal Average75 20 2.8 10 0.02% 20 46.4% 625 2.36% 2.33% 8.23% 28.15% 1050 260 130 2.09% 4.15% 22 0.57% 135 100

Soils68 30 6 10 2.0% 1000 49.0% 200 0.63% 0.63% 7.13% 3 3.O% 800 850 100 1.36% 1.37% 7 0.46% 100 200

Soils74 medians and (ranges) 25 (3-350) 0.3 (0.01-40) 20 (2-270) 2.0% (0.7--50%) 2000 (200-5000) 49% 200 (20-700) 0.50% (0.015-2.5%) 0.50% (0.04-0.9%) 7.10% ( 1.O-30%) 33.0% (25-4196) 800 (35-5300) 700 (30-1600) 100 (8- 1800) 1.4% (0.008-3.7%) 1.5% (0.07-50%) 7 (0.5-55) 0.50% (0.015-2.5%) 90 (3-500) 70 (5-1500)

Soils (this work) 31.4 (1.5-530) (1.5)* (0.5-30) 38.3 (0.9-1000) 2500 270 (6-7070) 1.09% (<0.005- 10%) 0.83% (0.005- 16%) 6.65% (0.07-20.3%) 433 (3-8200) 485 (18-1806) 1.83% (0.005-7.994)) 1.96% (0.01-32%) 10.1 (0.5-55) 0.5 1% (<0.006-3.4%) 108 (0.8-1000) 84 (0.9-1500)

D. J . Casagrande and L. D. Erchul, Geochim. Cosmochim. Acta. 1976, 40, 387. P. Pakarinen and K . Tolonen, Oikos, 1977. 28, 69. 890 P. Pakarinen and K . Tolonen. SUO,1977. 28,95. 8 9 ' H. H. Rump, K. Van Werden, and R. Herrmann, Caferia, 1977, 4, 149. 892 I. Yliruokanen, 5th Proc. Int. Peat Congress., 1976, 2, 276. 893 I. Yliruokanen, Kem-Kemi., 1980, I, 447. a94 K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-2/15, Springer-Verlag. Berlin. 895 G . Anderson, in 'The Role of Phosphorus in Agriculture'. ed., M. Stelly. Am. Soc. Agron., Crop Sci. SOC.Am., Soil Sci. SOC.Am.. Madison, Wisc.. USA. 1980, p. 412. R96 I. F. Largin, S. E. Priemskaya, A. N. Sventikhovskaya. and S. N . Tyuremnov, Proc. 4th Int. Peat Congress. Otaniemi, Finland, 1972, 77. 889

204

Environmen ta 1 Chemistry

Table 42 (cont.) Atomic Number

25 26 27 28 29 30 31 32 33 34 35 37 38 39 40 41 42 47 48 49 50 51 53 55 56 57 58 59 60 62 63 64 65 66 67 68 69 70 71 72 73 74 80 81 82 83 90 92

Mn Fe Co Ni Cu Zn Ga

Ge As Se Br Rb Sr

Y Zr Nb Mo Ag Cd In Sn Sb I cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta

w

Hg T1 Pb Bi Th U

Crusta 1 Average15 950 5.63% 25 75 55 70 15 1.5 1.8 0.05 2.5 90 375 33 165 20 1.5 0.07 0.2 0.1 2 0.2 0.5 3 425 30 60 8.2 28 6.0 1.2 5.4 0.9 3 .O 1.2 2.8 0.48 3 .O 0.50 3 2 1.5 0.08 0.45 12.5 0.17 9.6 2.7

Soils'" medians and (ranges)

Soils (this work)

1000 (20- 10 000) 4.0% (0.2-55%) 8 (0.05-65) 50 (2-750) 30 (2-250) 90 (1-900) 20 (2- 100) 1 (0.1-50) 6 (0.1-40) 0.4 (0.01-2) 10 (1-1 10) 150 (20-1000) 250 (4-2000) 40 (10-250) 400 (60-2000) 10 (6-300) 1.2 (0.1-40) 0.05 (0.01-8) 0.35 (0.01-2) 1 (0.7-3) 4(1-200) l(O.2-10) 5 (0.1-25) 4 (0.3-20) 500 (100-3000) 40 (2-180) 50 (3-170) 7 (3-12) 35 (4-63) 4.5 (0.6-23) 1 (0.1-3.2) 4 (2-6) 0.7 (0.1-1.6) 5 (2-12) 0.6 (0.4-2) 2 (0.6-6) 0.6 (0.3-1.2) 3 (0.04-12) 0.4 (0.1-0.7) 6 (0.5-34) 2 (0.4-6) 1.5 (0.5-83) 0.06 ( 0 . 0 1 4 . 5 ) 0.2 (0.1-0.8) 35 (2-300) 0.2 (0.1- 13) 9 (1-35) 2 (0.7-9.0)

760 (< 1-18 300) 3.2% (0.01-21%) 12 (0.3-200) 33.7 (0.1-1520) 25.8 (< 1-390) 59.8 (1.5-2000) 21.1 (2-200) (3.0)* (0.1-50) 11.3 (0.1-194) 0.4 (0.03-2) 42*6(0.27-850) 120 (1.5-1800) 278 (<3-3500) 27.7 (5-213) 345 (< 10-3000) (14)* (<6-300) 1.92 (0.07-27.5) (0.4)* (0.01-8) 0.62 ((0.005--8.1) (1.0)* (0.07-3) 5.8 ( 0 . 1 4 0 ) 1.7 (0.29-8.6) 7.08 ((0.09--210) (3)* (0.3-20) 568 (< 1-10 000) 4 1.2 (2.1-200) 84.2 (9.8-300) 6.5 (3.4-12) 43.6 (4.1-300) 6.0 (0.6-23) 1.28 (0.1-2.6) 3.5 (1.7-6.2) 0.85 (0.1 1-1.7) 5.66 (2.2-12) 0.80 (0.39-1.8 1) 3.0 (1.4-6.2) 0.62 (0.34-1.2) 3.94 (0.04-50) 0.46 ( 0 . 1 0 4 . 9 5 ) (7.7)* (0.5-20) ( 1.2)* (0.4-4) ( 1.1)* (0.5-3) 0.098 (0.004-4.6) (0.25)* (0.1-0.8) 29.2 (<1-888) (0.5)* (0.1- 13) 14 (0.5-72) 2.18 (0.76-14)

Mycotoxins BY D. S. P. PATTERSON

1 Introduction

It has long been known that certain moulds and larger fungi can be harmful to man and animals. Ergot and toadstool poisoning are obvious examples of the earliest known forms of fungal toxicity. But, by convention, toxins causing the latter form of poisoning are seldom termed mycotoxins. These then, are all formed by microscopic fungi or moulds, usually associated with foodcrops or animal feeds. In the 1940’s and 1950’s certain fungal metabolites were found to possess useful properties and, particularly following the discovery of penicillin, many substances with antibiotic properties were isolated from laboratory cultures. All such substances were mycotoxins by definition but their unique property was their selective toxicity towards pathogenic micro-organisms while remaining relatively harmless to man and animals undergoing treatment. At about the same time it was also suspected that some diseases could be attributed to fungal toxins that were ingested involuntarily in food. Thus, in Russia, an epidemic of a fatal disease known as Alimentary Toxic Aleukia (ATA) swept through the Ukraine following the use of over-wintered wheat in local bread making and in the United States serious losses of livestock were caused by ‘mouldy feed toxicosis’. The former disaster was investigated by Soviet scientists but at that time little of this was known to the world at large, and in general, illnesses associated with mouldy food or feeds attracted so little scientific attention that in 1962 Forgacs and Carll described rnycotoxicoses as ‘neglected diseases’ and in a text-book of veterinary toxicology published at about that time Garner2 stated that ‘in only a few instances has it been shown that extracts from fungi are harmful’. The situation suddenly began to change when aflatoxin was discovered as the cause of ‘Turkey X disease’, an epidemic that had been responsible for the death of thousands of poultry in the UK during 1960. As soon as it was realized that this newly described toxin not only caused acute liver disease but induced hepatomas in the trout and laboratory animals, research on aflatoxin gathered momentum on both sides of the Atlantic. Today there is a vast literature

’ J. Forgacs and W. T. Carll. A d ! ) V e f .Sci.,1962, 7, 273.

* R. J. Garner, ‘Veterinary Toxicology’, 2nd Ed, Bailliere, Tindall and Cox, London, 196 1, p. 303. 205

Environmental Chemistry

206

on the subject (see various reference works””) and even this is steadily being matched by research carried out on many more toxic metabolites of quite commonly occurring fungi. It is not possible to comprehensively review the literature in a short report of this kind: instead, a broad overview of the subject has been attempted. This has entailed a degree of selection and simplification but sufficient references have been provided for the reader to obtain detail when this is required. It will be seen that mycotoxins are to some extent inescapable contaminants of many foods and animal feedstuffs and as many are at least potentially harmful to man and animals they are worthy of serious consideration. Besides, it will also be evident that in the study of mycotoxins there is enormous scope for the chemist with interests in the biosynthesis of natural products, trace analysis, metabolism, molecular pathology, and even chemical engineering. 2 Biogenesis of Mycotoxins Growth of a fungus on cereal or other substrates does not necessarily denote the presence of my cotoxin because not all species and strains of fungi produce toxins and environmental conditions favouring optimal growth rarely coincide with those best suitable to toxin biosynthesis. Indeed, a number of physical, chemical, and biological factors’*#l 3 combine together to determine whether a particular mycotoxin is eventually produced on the substrate in question. H e ~ s e l t i n e ’has ~ listed the following determinants; moisture (relative humidity in the field, drying or re-wetting after harvest), temperature, mechanical damage (bruising, insects, birds, etc.), blending with other grain, influence of ‘hot spots’, time interval before harvest and length of storage period, gaseous environment (especially carbon dioxide and oxygen), chemical composition of the substrate, mineral nutrition, chemical treatment of the crop, plant ‘stress’, invertebrate vectors, spore load, plant varietal differences, fungal strain differences, and the nature of the microbiological ecosystem. Consequently, although the presence of potentially toxigenic species of the fungus can be established by mycological examination in the laboratory, it can L. A. Goldblatt (ed.), ‘Aflatoxin: Scientific Background, Control and Implications’, Academic Press, New York and London, 1969. A. Ciegler, S. Kadis, and S. J. Ajl (ed.), ‘Microbial Toxins’, Vol. VI, ‘Fungal Toxins‘. Academic Press, New York and London, 197 1. S. Kadis. A. Ciegler. and S. J . Ajl (ed.), ‘Microbial Toxins’. Vol. VII, ‘Algal and Fungal Toxins’, Academic Press. New York and London. 1972. I. F. H. Purchase (ed.), ‘Mycotoxins’. Elsevier Scientific Publishing Co., Amsterdam, Oxford and New York, 1974. J . V . Rodricks (ed.), ‘Mycotoxins and other Fungal Related Food Problems’, Adr. Chem. Ser., American Chemical Society, Washington DC. 1976. No. 149. J. V . Rodricks, C . W . Hesseltine, and M. A. Mehlman (ed.), ‘Mycotoxins in Human and Animal Health’, Pathotox Publishers Inc., Park Forest South, Illinois, 1977. 9 T . D. Wyllie and L. G . Morehouse (ed.), ‘Mycotoxic Fungi, Mycotoxins, Mycotoxicoses: an Encyclopedic Handbook’, 3 Vols. Marcel Dekker, New York and Basel, 1977 and 1978. loK. Uraguchi and K. Yamazaki (ed.), ‘Toxicology, Biochemistry and Pathology of Mycotoxins’, Kodansha Ltd.. Tokyo and John Wiley, New York. 1978. I I J . G. Heathcote and J. R. Hibbert. ‘Aflatoxins: Chemical and Biological Aspects’, Elsevier Scientific Publishing Co., Amsterdam, Oxford and New York. 1978. J . Lacey. S. T. Hill, and M. A. Edwards. Trop. Stored Prod. InJ, 1980. 39. 19. I ’ C . W. Hesseltine, i n ‘Mycotoxins and other Fungal Related Food Problems’, ed. J. V . Rodricks, A&. Chem. Ser., American Chemical Society, Washington DC. 1976, No. 149, p. 1.

’

‘

’

’*

Mycotoxins

20 7 x

F w C

4

3

208

Environmental Chemistry

never provide certain evidence for the presence in food of the relevant mycotoxin. This can only be done by direct chemical analysis (see Section 4). It is possible to distinguish two broad types of fungal metabolism, primary and secondary. Primary metabolism, while cells are still multiplying, involves aerobic and anerobic respiration, the energy-requiring processes of cell growth, maintenance, and division, and the synthesis of structural and functional macromolecules. Secondary metabolism, is a characteristic of the senescent organism and, for example, is observable in a laboratory culture following a period of exponential growth when there is no longer an increase in the biomass. At this stage different use is made of certain basic intermediate metabolites, such as acetate, malonate, mevalonate, pyruvate, and amino-acids, which are utilized in the synthesis of complex molecules having no obvious physiological function 1 4 . These ‘secondary metabolites’ constitute a chemically diverse group of compounds that can readily be classified into closely related families such as coumarins, flavonoids, ketides, macrolides, pyrroles, and terpenoids. Many are pigments and others possess antibiotic or toxic properties. It is the latter type of compound that concerns us at present and in Figure 1 is shown the broad relationship between primary and secondary metabolism and the origins of some mycotoxins. Citrinin (see Figure 2) provides a simple example and is synthesized by the so-called polyketide pathway. which involves the head-to-tail condensation of 5 acetate units, cyclization, and the insertion of two methyl groups from methionine. Sterigmatocystin and aflatoxin arise by a fairly complex route but this too initially involves the formation of a polyketide chain. The isocoumarin moiety of the ochratoxin A molecule is formed from one acetate and 4 malonate units followed by chlorination and the subsequent condensation with phenylalanine. Many of the trichothecene mycotoxins (see Figure 2 for their general structure) are sesquiterpenes and are derived through the mevalonate pathway with the basic trichothacene skeleton being formed from farnesyl pyrophosphate. An early catalogue of fungal metabolites was compiled by TurnerI5 in 1971 and biosynthetic pathways were considered in an even earlier symposium.16 Individual chapters of the various treatises 3-11 have subsequently provided detail of the pathways relating specifically to mycotoxins and an authoritative account of their biosynthesis has just (1 980) become available.” A given mycotoxin often appears to be produced by a restricted number of fungal species but this is not generally so. For example. patulin, which at one time was tested clinically for its antibiotic potential. can be produced by at least 12 Penicillium species, three Aspergillus species, three Aspergillus species, one or more species of B-vssochlamys and perhaps other fungi.

l4 l5

I‘

E. D. Weinburg, Perspect. B i d . Med., 1971, 14. 5 6 5 . W. B. Turner, ‘Fungal Metabolites’, Academic Press. New York and London. 197 1. Z. Vanek and Z. Hostalek (ed.), ‘Riogenesis of Antibiotic Substances‘. Academic Press. New York and London, 1965. P. S. Steyn (cd.). ‘The Biosynthesis of Mycotoxins. A Study in Secondary Metabolism’. Academic Press. New Yark, London, Toronto, Sydney and San Francisco. 1980.

M y cotoxins

209

3 The Importance of Mycotoxins in the Environment This can be assessed in at least two ways; first, by their frequency of detection in food and animal feeds and secondly, according to their toxicological potency. Mycotoxins in Food and Feeds.-Fungal contamination of the basic food commodities can arise either when a plant is growing in the field or after harvest when stored. Manufactured or prepared food can also become contaminated during storage. For example, amongst other fungal species, living plants may be colonized by Fusarium graminearum (producing zearalenone) and Aspergillus fravus (aflatoxin), while stored material can support the growth of A . flavus and A . parasiticus (both producing aflatoxin), A . uersicolor (sterigmatocystin), A . ochraceus (ochratoxin A), and several Fusarium species (zearalenone and trichothecene mycotoxins). Some 30 mycotoxins have been found to be occasional contaminants of food or animal feed but they are not equally common. Indeed in the UK traces of only the following mycotoxins have so far been d e t e ~ t e d : ’ ~aflatoxins -~~ B,, B,, GI, G,, and M citrinin, ochratoxin A, patulin, sterigmatocystin, T2-toxin, vomitoxin, and zearalenone (Figure 2). Toxicological Potencies of Mycotoxins.-LD,, values determined in the rat do not provide a very satisfactory means of assessing the relative importance of different mycotoxins as they generally fall within a fairly close range of 7-25 mg kg-’ body weight. Altogether different values may be obtained in other laboratory animals, although sex, strain, various dietary factors, and the route of administration also influence the determination of an LD,, value. The only toxin that is evidently different from the others on this basis is zearalenone, which has been said to have an LD,, value in excess of 16 g kg-’ body weight 24 and, although this compound is usually termed a mycotoxin, it is therefore not an acute toxin at all. It is a potent oestrogen, however, particularly in the pig.25 When mycotoxins are considered as largely inevitable environmental contaminants, perhaps their potential for causing chronic toxicity is a more important attribute. At least in man, single large dose acute toxicity is unlikely to occur because high toxin concentrations are often accompanied by macroscopic moulding of food which then has an unpleasant appearance and flavour. Therefore chronic exposure to very small amounts of mycotoxin would appear to present the greater risk to man. Animals also resist eating mouldy feed but not always to the

’’ B. J. Shreeve. D. S. P. Patterson, and B. A. Roberts, Vet. Rec.. 1975, 97,275. ’’D. S. P. Patterson. B. A. Roberts, B. J . Shreeve, A. E. Wrathall, and M . Gitter, Ann. Nutr. Aliment., 1977. 31. 643. D. S. P. Patterson, E. M. Glancy, and B. A. Roberts, Food Costnet. Toxicol., 1980, 18, 35. ” D. C. Hunt, L. A. Philp, and N. T. Crosby,Ana!,ist (London), 1979, 104, 1171. 2 2 A. E. Buckle, Proc. 2nd. int. Confr. Vet. Pharrnacol. Toxicol. Therap., 198 1, in press. 23 Anon., Food Surveillance Paper No. 4. ‘Survey of Mycotoxins in the United Kingdom’, H.M.S.O., London. 1980. 24 D. E. Bailey. G. E. Cox, K. Morgareide. and J. Taylor. Toxicol. A p p l . Pharrnacol., 1976, 37, 144. 2 5 C. J. Mirocha and C. M. Christensen, in ‘Mycotoxins’, ed. I. F. H. Purchase, Elsevier Scientific Publishing Co.. Amsterdam, Oxford and New York, 1974, p. 129.

2o

2 10

Environmental Chemistry

0

0

-CH

-CH2-CH,-

113)

= CH-CH,OH

-CH,OH

-C=O

-CH=CH-

1121

ill1

CS

c,

c,

1171

116)

115)

4

-0COCH3 -H

-OH

-OCOCH,

R2

-OH

-OH

R'

-OH

-0COCH3

-0COCH3

R3

'14'

P4

,,

-OH

-H

-H

I

OH

Figure 2 Structural formulae of some mycotoxins and their metabolites; (1) aflatoxin B ( 2 ) aflatoxin B,, ( 3 ) aflatoxin MI, (4) aflatoxin G , , ( 5 ) aflutoxin, G,, ( 6 ) uflatoxicol, ( 7 ) sterigrnatocystin, (8) ochratoxin A, (9) citrinin, (10) patulin, (1 1) zearalenone, (12) zearalenol, (13) zearalanol, (14) general structure of trichothecene mycotoxins, (1 5 ) diacetoxyscirpenol, ( 16) T2-toxin, (1 7 ) deoxynivalenol (vomitoxin)

HO

COOH

=O

-0COCH2CHICH312

-H

P5

Environmental Chemistry

212

point of starvation and as compounded feeds are usually flavoured, the presence of trace amounts of mycotoxins does not usually diminish palatibility. Numerous environmental chemicals including some mycotoxins have now been screened for embryotoxic, teratogenic, mutagenic, and carcinogenic properties. The pregnant rat, mouse, or guinea-pig are the usual laboratory test animals for embryotoxic and teratogenic effects.26 Mutagenicity is usually determined in an in vitro bacterial test system, with 27 or without 28 prior ‘activation’ by rodent-liver microsome preparations, and susceptible strains of the rat 29 or the rainbow trout 30 are used for carcinogenicity trials. Table 1 summarizes these biological effects of aflatoxins B and M,, ochratoxin A, patulin, sterigmatocystin, and T2-toxin. Ochratoxin A and T2-toxin are teratogenic and aflatoxin B, and patulin may be also. Aflatoxin B, and M , and sterigmatocystin behave as mutagens in one test system and patulin and sterigmatocystin in another. Where both biological activities have been tested for, mutagenicity seems to correlate with carcinogenic potential. In unconfirmed reports, ochratoxin A31,32has been shown to be carcinogenic and patulin induces tumours only at an intradermal injection site.32 The only other common toxins which are known to be carcinogenic are aflatoxin B,, aflatoxin MI, penicillic acid, and sterigmatocy~tin.~~ All except penicillic acid have been detected in food or animal feeds in the UK, but because of their more frequent detection in albeit low concentrations the aflatoxins would certainly appear to possess the greatest potential to harm animal and public health. Table 1 Biological effects of some mycotoxins Mvcotoxin Aflatoxin B, Aflatoxin M, Citrinin Ochratoxin A Patulin Sterigmatocy stin T2-toxin Zearalenone

Target organ

Acute toxicity LD5, mg kg liver 0.36 ( o ; d ) liver 0.32 (0:d) kidney 35 (sc; rn) kidney, liver 2 0 - 2 2 (0: r) nervous system. 10 (sc: rn) visceral organs liver, kidney 120 (o:r) skin (contact). stomach. 4 ( 0 : r) bone marrow reproductive 16 000 ( 0 ; r) system

‘

Embryotoxic

Teratogenic

Mutagenic

+

+

nt

nt

+ +

+

-

+ +

+

nt

nt

+ +

*

+ -

+

Carcinogenic

+

+

-

+ +

+

+

+

-

f

-

+

nt

Adapted from, B. J. Wilson and A. W. Hayes, in ‘Toxicants Occurring Naturally in Foods’, National Academy of Sciences, Washington DC. 1973, p. 372: A. W. Hayes, M.vcopa/ho/ogia.1978. 65,29: Clin. Toxicol., 1980. 17,45 Abbreviations: o = oral, sc = subcutaneous, d = duckling. m = mouse. r = rat, nt : not tezted

General Attributes of Mycotoxic Disease.-Mycotoxins are chemically diverse (see Figure 2) and their toxic effects are just as varied since they can interact with almost any organ or physiological system of the body (Table 1). Consequently the A. W. Hayes, R. D. Hood, and H. L. Lee, Teratology, 1974,9,93. B. N. Ames, W. E. Durston, E. Yamasaki, and F. D. Lee, Proc. Null. Acad. Sci. USA., 1973, 70, 228 1. 28 Y. Ueno and K. Kubota, Cancer Res., 1976, 36,445. 2y International Agency for Research on Cancer, IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man, Vol. 10,‘Some naturally occurring substances’, IARC, Lyon, 1976. R. 0. Sinnhuber, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks, C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc., Park Forest South, Illinois. 1977, p. 7 3 1 . 3 1 M. Kanisawa and S. Suzuki, Gann, 1978, 69,599. 32 M. Kanisawa and S. Suzuki, Abs. Annu. Meet. Am. SOC. Microbiol., 1979, Abs. 205. 3 3 F. Dickens and H. E. H. Jones, Br. J. Cancer, 1961, IS, 85. 26

27

Mycotoxins

213

characteristics of mycotoxic disease can only be defined in the broadest of terms, although the cardinal feature of all such diseases is that they are food or feed related. The following diagnostic criteria are based on those originally proposed by Forgacs and Carl1 and, essentially, the same criteria apply to mycotoxic disease of man: (1) the illness under investigation has no readily identifiable cause, (2) the condition is not transmissible, (3) syndromes are associated with particular consignments or batches of feed, (4) treatment with antibiotics or vitamins has little effect, and ( 5 ) outbreaks are often seasonal because weather conditions influence the growth of mould on harvested crops or stored feed.

2, adapted Clinical Diseases of Farm Animals Caused by Mycotoxins.-Table from ref. 34, lists the clinical conditions of farm animals that have arisen naturally or have been produced experimentally following the ingestion of feeds contaminated with certain mycotoxins. Here the list has been extended to include a few toxins that are so far unknown in the UK as natural contaminants, but which have been encountered in animal feeds in the United States and on the continent of Europe. Whenever mycotoxicosis has been suspected in the field, it has always been difficult reliably to establish causal relationships between clinical disease and the presence of mycotoxins in animal feeds. This is partly because contamination is almost always patchy and truly representative samples can rarely have been obtained for chemical analysis. Another difficulty is that naturally moulded feeds are usually contaminated with several fungal species and while more than one may be toxigenic, the predominance of one toxin or the availability of analytical methods may in practice determine which mycotoxin is actually detected. Human Mycotoxicosis.-Amongst the metabolic products of microscopic fungi, 4 toxins have been implicated in human disease; ergot, trichothecene mycotoxins (probably T2-toxin), aflatoxin B,, and ochratoxin A. Ergotism in man is a well-known hazard of contaminated food35 and was the first such disease known to man, outbreaks in the Middle Ages being called ‘St. Anthony’s Fire’. The last outbreak of note36probably attributable to ergot occurred in France in 195 1. The war-time epidemic of ATA in Russia, mentioned briefly above, has been described in some detail by J ~ f f e . ~ ’An ? ~ authentic * sample of crude toxin originally isolated from food implicated in the outbreaks of disease during the 1940’s has recently been found to contain 3 trichothecene mycotoxins (T2-toxin, neosolaniol, T2-tetraol) and ~ e a r a l e n o n eConsequently, .~~ the presence in food of one or more of B. J. Shreeve and D. S. P. Patterson, Vet. Rec., 1975, 97, 279. S. J. van Rensburg and B. Altenkirk, in ‘Mycotoxins’, ed. I. F. H. Purchase, Elsevier Scientific Publishing Co., Amsterdam, Oxford and New York, 1974. p. 69. 36 Anon., L f e , 1951, 31. 25 (cited by B. J . Wilson and A. W. Hayes in ‘Toxicants Occurring Naturally in Foods’, Natl. Acad. Sci. USA, Washington DC, 1973, p. 372.) 37 A. Z. Joffe, in ‘Microbial Toxins’, Vol. VII, ed. S. Kadis, A. Ciegler, and S. J. Ajl, Academic Press, New York and London, 1971, p. 139. 38 A. Z. Joffe, in ‘Mycotoxins’, ed. I. F. H. Purchase, Elsevier Scientific Publishing Co., Amsterdam, Oxford and New York, 1974. p. 229. 3y C . J. Mirocha and S. V. Pathre, Appl. Microbiol., 1973. 26, 7 19. 34

35

!earalenone

rrichothecenes (T2-toxin detected)

Patulin

Sporidesmin

M n d i f i ~frnm I R 1 Phrepve and

Neither a toxigenic fungal strain nor the toxin known in the UK

n <

A . ochraceus

Ochratoxin A

P Pattercon Vot R o r

Pithomwes chartarum

1 9 7 2 07 379

Dead ryegrass

Stored feed. pasture soil

P. qdopium

P. raistrickii

Standing crops

Maize. grain

F. tnoniliforme

F. graminearum

Hay. straw

Stored cereals

F. tricinctum

Stachj-botrrs alternans

Stored feed. silage Fescue grass

Stored cereals. feeds

Stored feeds and growing crops (especially oil seeds) Ryegrass and other pasture

Substrate

P . urticae Byssochlamys spp. F. tricinctum

P. uiridicatum

Claikeps p ii rpu rea

A . parasiticus

A.Jlovus

Typical fungal species (slrain dlfferences exist)*

Ergot alkaloids

Aflatoxin B ,

Mycotoxin

of fungus isolated Verruculogen in the UK

Mycotoxins detected in animal feeds in the UK

Category

Table 2 Diseases of farm animals caused by m-vcotoxins

*A

Cattle

Abortion. oestrogenic effects (vulvo-vaginitis) As for cattle

Emesis. intestinal haemorrhage. death

Pol ydipsia. polyuria. enlarged kidney

Reduced fertility. agalactia

Unthriftiness. jaundice. liver failure

Pigs

Animal rpecies

P = Penicillium

Facial eczema. photosensitization syndrome

As for cattle

= A ~ n ~ r ~ i l l Fu v =. Fuwrium. and

Trembling. ataxia. recumbency. death

Haemorrhages. death ‘Fescue foot’ (gangrene) ‘Mouldv corn toxicosis’. widespread haemorrhage. death Stomatitis. scouring. death

Gangrene of feet

Reduced growth rate. drop in milk production

~~

Poirltry

Horsey

-

-

Dvspnoea. trembling. ataxia

Stomatitis. throm boc yt open I a. death Leukoencephalitis. ataxia. circling. death

-

-

Small eggs. drop in egg production

-

‘Moldy corn disease’. oral lesions

Poor growth rate. drop in egg production. acute liver haemorrhage -

Mycotoxins

215

these toxins, and particularly T2-toxin, may have been responsible for the outbreak of ATA. In India40-43 and e l ~ e w h e r e aflatoxin ~ ~ . ~ ~ B , has been detected in food eaten by patients or their domestic pets suffering from acute liver failure, and there is some epidemiological evidence to suggest a link between the ingestion of aflatoxincontaminated food and Reye’s syndrome (encephalopathy with fatty degeneration of the viscera) in ~ h i l d r e n ~and ~ -primary ~~ liver-cell cancer in a d ~ l t s . ~ ~ , ~ ~ Ochratoxin A has been identified as one of the contributory causes of porcine nephropathy, mainly in Denmark.” A comparable illness of man in the Balkan _ _ fungus

/

,

-

/

toxlns produced in laborotory cultures

J* growing crops

\

i

stored cereals and nuts

I I

/

I

, /

/

fungal extracts, pure toxins

/ /

\ /

*

i

\ * 4

\

food for human consumption

I animal feed

\ \

occupational exposure animals

* waste

animal products (human f o o d )

*

=possible control points

Figure 3 Mycotoxins in the environment. Growing or harvested crops may be infected with a fungus and the toxin it produces passed directly or indirectly to man’s food. Pathways f o r occupational exposure to mycotoxins are also indicated

K. A. V. R. Krishnamachari, R. V. Bhat, V. Nagarajan, and T. B. G. Tilak, Lancet, 1975, ii, 1061. K. A. V. R. Krishnamachari, R. V. Bhat, V. Nagarajan, and T. B. G. Tilak, Indian J . Med. Res., 1975,63, 1036. 4 2 B. N. Tandon, L. Krishnamurthy, A. Koshy, H. D. Tandon. V. Ramalingaswami, J. R. Bhandari, M. M . Mathur, and P. D. Mathur, Gastroenterology, 1977, 72,488. 4 3 H. D. Tandon, B. N. Tandon, and V. Ramalingaswami,Arch. Pathol. Lab. Med., 1978, 102,372. 44 T. C. Campbell and L. Stoloff, J. Agric. Food Chem., 1974, 22, 1006. ” Anon., The Weekly Review (Nairobi), Nov. 10, 1978, p. 24; J. E. Price and R. Heinonen, Kenya Vet., 1978,2,45. 46 R. C. Shank, C. H. Bourgeois, N. Keschamaras, and C. Chandavimold, Food Comet. Tuxicol., 1971. 9, 501. 4’ I. Dvorackova, V . Kusak, D. Vesely, J. Vesela, and P. Nesdinol, Ann. Nutr. Aliment., 1977, 31.977. 48 G. R. Hogan, N. J . Ryan, and A. W. Hayes, Lancet, 1978, i, 56 I. 49 F. G. Peers and C. A. Linsell, Ann. Nutr. Aliment., 1977, 31, 1005. 50 World Health Organization, Environmental Health Criteria, No. I 1, ‘Mycotoxins’, W.H.O. Geneva, 1979. J 1 P. Krogh in ‘Mycotoxins’, ed. I. F. H. Purchase, Elsevier Scientific Publishing Co., Amsterdam, Oxford and New York. 1974, p. 419.

40

“

Environmental Chemistyy

216

countries has also been tentatively attributed to this toxinS2but the causes of this and other forms of mycotoxic n e p h r ~ p a t h yare ~ ~probably complex. A report published by the World Health OrganizationS0 considered the public health implications of mycotoxins in detail and the essential problem posed by mycotoxins as contaminants of the environment is illustrated diagramatically in Figure 3. It shows three routes by which man may become exposed to mycotoxins: ( a ) directly by eating cereals, nuts, and other vegetable products that are contaminated by toxigenic fungi, (b) indirectly by consuming meat, milk, and eggs that might contain residues of mycotoxins or their metabolites ‘carried over’ from contaminated animal feeds. (c) as an occupational hazard workers in the food and feed industries may inhale dust or otherwise be exposed to contaminated ingredients, and (d) certain laboratory workers may face similar hazards when they prepare or use crude and pure toxins prepared from fungal cultures.

4 Analysis of Mycotoxins simplest task for the analyst is to determine The Analytical Problem.-The quantities of mycotoxins formed in laboratory cultures of specific toxigenic fungi. Concentrations of the toxin can be high (several mg g-I) and extracts in organic solvents are usually relatively free from interfering substances. The sensitivity of detection systems are often such that purification is unnecessary and the extract can be diluted before quantification. The more usual problem facing the agricultural and food chemist is much more difficult. He is required to identify and determine trace amounts ( p g k g - ’ ) of a particular toxin in one of a range of chemically complex matrices including cereals, nuts, pasture samples, hay, straw, silage, mixed animal feeds, processed and cooked food, meat. eggs, and milk. In some cases possible interfering substances may actually have been added. Thus mixed anim,al feeds contain added oil, vitamins, antibiotics, and antioxidants and human foods contain various preservatives as well as artifacts produced by cooking or processing. Just as specific methods are needed for the quantitative analysis of a given toxin, a specific extraction and purification procedure ideally is required for each type of sample. But, in practice, this is not possible and methods are usually applicable to a narrow range of similar foods or feeds. The problem is further complicated because the analyst frequently does not know which, if any, mycotoxin is present in the suspect sample submitted to him. and this has led to the development of the multimycotoxin screening P. Krogh. N. H. Axelsen. F. Elling, N. Gyrd-Hansen. B. Hald. J . Hyldgaard-Jensen. A. E. Larsen, A. Madsen, H. P. Mortensen, T. Mailer, 0. K. Petersen, U . Ravnskov, M . Rostgaard, and 0. Aalund, Acla. Palhol. Microbiol. Scatid., Secl. A , 1974. Suppl. 246, p. I . 53 G. C. Peristianis, P. K. C. Austwick. and K. L. Carter, Yirchows Archizl. R , 1978, 28. 321. 5 4 R. M. Eppley. J . Assoc. O f i Anal. Chem.. 1968. 5 1. 74. L. Stoloff. S. Nesheim, J. V . Rodricks, M. Stack, and A . D. Campbell. J. Assoc. Oif Anal. Chem., 1971. 54, 91. 56 B. A. Roberts and D. S . P. Patterson, J . Assoc. OjJ Anal. Chcm.. 1975. 58, I 178. D. S. P. Patterson and B. A. Roberts. J . Assoc. OJK A n a l . Chcm.. 1979. 62, 1265. 6. G. E. Josefsson and T. E. Moller, J . Assoc. O f l A n a l . Cheni.. 1977.60. 1369. 5 9 A. Gimeno, J . Assoc. Off: Anal. Chetn.. 1979. 62. 579. 6o Y . E. Takeda. E. Isohata. R. Amano. and M. Uchiyarna. J . Assoc. O f l A n a l . Chem.. 1979. 62. 573. 52

’’

’’ ’’

217

Mycotoxins Table 3 Chemical analyses of mvcotoxins infood and feedstugs Basic steps (1) Sampling, sample preparation (2) Extraction (3) Purification (clean-up)

(4) Final separation

( 5 ) Detection, quantitation

(6) Confirmation

Brief description of general or alternative procedures mix, grind, sub-sample (general) agitate dry or wet sample with organic solvent (general) liquid-liquid partition precipitate impurities with salts of divalent metals column chromatography preliminary development of t.1.c. plate with diethyl ether dialysis t.1.c. (one- or two-dimensional) h.p.1.c. g.c. miniature multi-layer chromatography column (rapid screening method) fluorescence (t.l.c.*, h.p.1.c.) absorbance (t.l.c.*, h.p.1.c.) visible reaction product (t.l.c.*) flame ionization (g.c., derivative) electron capture (g.c., derivative) co-chromatography (t.l.c., h.p.1.c.) derivative (t.l.c., h.p.1.c.) mass spectrometry biological test

* Quantitation on t.1.c. is by densitometry or semi-quantitative visual comparison with standards

which is an analytical compromise. Such a method has as high as possible sensitivity for a small number of toxins that are thought likely to be present in food or animal feed of inferior quality and is applicable to as wide a range of commodities as possible. When the result of the 'screen' is positive it would be followed by a specific quantitative analysis. Estimates of the concentrations of mycotoxins in food or feeds are markedly dependent upon the sample selected for chemical analysis. As already mentioned, moulding and the mycotoxin Contamination are generally uneven and, for example, in a 50 g sample of peanuts with a mean concentration of 30 pg aflatoxin B, kg-' it is quite conceivable that the entire content of 1.5 pg aflatoxin B, could be located in a single nut. Similarly, pockets of moulded animal feed may contain high concentrations of a toxin while the bulk of the feed is relatively uncontaminated. This uneven distribution of mycotoxins may well be of some significance in the epidemiology of mycotoxin-induced disease, but for regulatory and investigational purposes representative well-mixed samples of food or feed are required for chemical analysis. The basic steps involved in mycotoxin analysis are summarized in Table 3. Sampling Procedures.-Because of the very uneven distribution of mycotoxins in crops and stored commodities sampling is subject to considerable error. Thus, it has been shown6' that even when large samples (21.8 kg) were taken from consignments of peanuts with a mean aflatoxin concentration of 20 pg kg-', the coefficient of variation (CV) due to sampling was 60%. With its greatly reduced

218

En u ironrn en t aI C hem is t ry

particle size the CV of a smaller sub-sample (1.1 kg) of ground peanuts was only 18% compared with 16% for the chemical analysis. The mathematical and statistical t h e o r i e ~ ~ lapplicable -~~ to mycotoxin contamination have been developed by several investigators and in the case of aflatoxin contamination samples procedures have been devised6’ so as to give optimum protection to the consumer and the US Peanut Industry alike. Practical sampling plans concerned with mycotoxin surveys have also been r e ~ i e w e d . ~ ~ , ~ ~ In the UK, legally valid analytical figures for aflatoxin and certain other contaminants of agricultural commodities may be obtained only when sampling procedures laid down in the appropriate Fertilisers and Feeding Stuffs Regulations66 have been followed. For example, when applied to a consignment of 100 packages of feed in the form of a meal, this involves taking a similar quantity from 10 or, in general, the square root of the number of packages. The individual samples are thoroughly mixed in a manner described and by a process of ‘quartering’ reduced to a sub-sample of 1-2 kg. Before analysis, it is finally ground in a suitable mill. Representative samples of fruit, meat, and eggs can be obtained by homogenizing appropriate quantities in a food blender, whereas already homogenous foods like milk and fruit juice can be taken directly for analysis without preparatory treatment. Preparation of samples is discussed in detail by Jones,67 in the official methods of analysis of the Association of Official Analytical Chemists,68 and in a review by Schuller et Analytical Methods.-Chemical analysis, bioassay, and radioimmunoassay have all been used for the detection and measurement of mycotoxins in food and feeds. Details of only one bioassay are included in the AOAC Official Methods of Analysis6* and this is for aflatoxin using the chick embryo as the test system. Possibly, the brine shrimp larva ( Artemia salina) test 69 has found wider application as a general screen for mycotoxins but it is subject to interference from other toxic extractants including fatty acids.70 Radioimmunoassay systems assay procedures have been developed for the a f l a t o x i n ~ ochratoxin ,~~ A,72 and T 2 - t o ~ i nbut ~ ~it is almost impossible to devise an assay that is sufficiently specific for a single member of a group of closely related mycotoxins (e.g., the aflatoxins) and the sensitivity of T. B. Whitaker, Pure Appl. Chem., 1977, 49, 1709. G. Berry and N. E. Day, Am. J. Epidemiol., 1973, 97, 160. W. F. Kwolek and E. B. Lillehoj, J. Assoc. O f l Anal. Chem., 1976,59, 787. 64 P. L. Schuller, W. Horwitz, and L. Stoloff, J . Assoc. OffAnal. Chem., 1976, 59, 13 15. 6J N. D. Davis, J. W. Dickens, R. L. Freie, P. B. Hamilton, 0. L. Shotwell, T. D. Wyllie, and J. F. Fulkerson, J. Assoc. O f l Anal. Chem., 1980, 63, 95. 66 Anon., Fertilisers and Feeding Stuffs Regulations, Statutory Instrument No. 1521, 1973, H.M.S.O., London. 67 B. D. Jones, ‘Methods of Aflatoxin Analysis’, Report G70, Tropical Products Institute, London, 1972. Association of Official Analytical Chemists, ‘Official Methods of Analysis’, 13th Edn., Chapter 26 ‘Natural Poisons’ (issued separately), 1980, AOAC Washington DC. 69 J. Harwig and P. M. Scott, Appl. Microbiol., 1971, 21, 1011. lo R. F. Curtis, D. T. Coxon, and G . Levett, Food Cosmef. Toxicol., 1974, 12,233. ” G. Yang, S. Nesheim, J. Benavides, I. Ueno, A. D. Campbell, and A. Pohland, Zenfralbl.Bakf., 1980, Suppl. 8, 329. ” F. S. Chu, F. C. C. Chang, and R. D. Hinsdall, Appl. Enuiron. Microbiol., 1976, 31, 831. 73 F. S. Chu, S. Grossman, R.-D. Wei, and C. J. Mirocha, Appl. Enoiron. Microbiol., 1979, 37. 104.

M y cot oxins

219

these assays are little different from t.1.c. or h.p.1.c. methods. Official quantitative AOAC methods (as at 1980; ref. 68) still involve t.l.c., although the current trend in mycotoxin methodology is to use h.p.1.c. instead. A case can be made for the use of both, the one technique complementing the other. Only collaboratively tested methods are recommended by the AOAC and at present these are limited to the following mycotoxins in food and animal feed; aflatoxins B,, B,, G,, G,, and M,, ochratoxin A, patulin, and sterigmatocystin.68 In the UK the Tropical Products Institute was first to issue a handbook of recommended methods6’ for aflatoxin and a method for aflatoxin B,74 used throughout the European Economic Community (E.E.C.) is laid down by the current Fertilisers and Feeding Stuffs Regulations. This has an analytical limit of about 10 ,ug aflatoxin B, kg-’, employs t.l.c., and is very similar to the ‘CB’ method.68 In these procedures separate extraction and clean-up steps are generally recommended for the specific toxins and different types of food and feedstuff. Determination by t.1.c. is by visual or densitometric comparison with standard amounts of pure toxin applied to the same chromatoplate as the extract. This is done either directly after evaporating the developing solvent or subsequently after reaction with a spray or dip reagent. Plates are viewed or scanned under visible or U.V. illumination. As shown in Table 4, of the commonly occurring mycotoxins, aflatoxin B is most appropriately determined by t.l.c., sub-nanogram amounts being readily detected. Confirmation of the identity of a mycotoxin usually involves co-chromatography (the standard toxin is mixed with the unknown on the chromatoplate prior to t.1.c.) in several developing solvents and derivitization followed by t.1.c. with the pure toxin treated ~imilarly.~*.’~

,

Table 4 Minimum quantities ofpure mycotoxins detected on t.1.c. Mycotoxin and how visualized Nativefluorescence in U.V. light Aflatoxin B, Citrinin Zearalenone Spray reagent producing or increasing fluorescence in u.v. light T2-toxin Ochratoxin A Sterigmatocystin Diacetoxy scirpenol Spray reagent producing a visible spot Patulin Penitrem A

Quantity detected (ng) 0.4 10

Moles detected relative to aflatoxin B I

20

1 31 49

10 20 20 50

39 48 108

20 1000

100 1215

16

Data from, B. A. Roberts and D. S . P. Patterson, J. Assoc. OffAnal. Chem., 1975, 58, I178 Anon., Fertilisers and Feeding Stuffs (Amendment) Regulations, Statutory Instrument No. 840, 1976, H.M.S.O., London. l5 B. A. Roberts and D. S . P. Patterson, Proc. 2nd Meet. Mvcotoxins Animal Disease, Aberdeen, 1976, p. 42. 74

220

Environmental Chemistry

A group of 30 to 40 mycotoxins formed by Fusariurn and certain other fungal species, known collectively as the trichothecene mycotoxins, possess few exploitable chemical properties and, indeed, the sole functional groups of many members consist of an isolated double bond and an epoxide (see Figure 2). They do not fluoresce or absorb U.V. light to any significant extent and on t.1.c. milligram amounts of untreated trichothecene would be undetectable. However, they are converted to unknown but highly fluorescent derivatives by strong acids and the epoxide reagent of Hammock et al.,76 4-(p-nitrobenzyl)pyridine, permits the detection of about 200 pg T2-toxin kg-I animal feed77 and provides some specificity. Suitable extracts of contaminated feed may also be assayed biologically making use of the fact that about 0.5 pg of diacetoxyscirpenol and T2-toxin produce an erythematous skin reaction in the guinea-pig. This permits the detection of trichothecene mycotoxins at concentrations of about 100 pg kg-I of feedstuff.78 Gas chromatography-mass spectrometry (g.c.-m.s. with selected ion monitoring) is a powerful tool for the identification and quantification of my cot ox in^^^ but this technique is currently the preserve of the specialist laboratory. As an example of its application to the analysis of trichothecenes in agricultural commodities, it has been recorded** that, although t.1.c. and dermal bioassay failed to detect the presence of epoxide-containing skin irritants in appropriate feedstuff extracts, g.c.-m.s. confidently revealed the presence of 10 pg T2-toxin kg-' of barley. Fast semi-quantitative methods have a special place in mycotoxin analysis as the suitability of consignments of agricultural commodities often need to be decided quickly. Peanuts (groundnuts) or corn (maize) kernels contaminated with aflatoxin fluoresce under U.V. light, partly due to the intrinsic fluorescence of aflatoxin B, and partly due to the fluorescence of other fungal metabolites, notably kojic acid [5-hydroxy 2-(hydroxymethyl)4 pyrone1.80It has been found empirically that there is a good correlation between bright greenish yellow (BGY) fluorescence and aflatoxin contamination," and it has therefore been possible to devise electronic sorting procedures 82 to separate substandard kernels mechanically. Another screening method for aflatoxin c o n t a r n i n a t i ~ n ~depends ~ * ' ~ upon the fact that crude organic extracts of corn fluoresce when treated with an iodine reagent. This is slightly more elaborate than the BGY test but it is claimed to be more specific. Increased specificity and semi-quantitative assessment can be achieved with various 'mini-column' methods, some of which have been tested collaboratively and L. G. Hammock, B. D. Hammock, and J . E. Casia, Bull. Environ. Contam. Toxicol., 1974, 12, 759. S. Takitani, Y. Asabe, T. Kato, M. Suzuki, and Y. Ueno,J. Chromatogr., 1979, 172, 3 5 5 . '' D. S. P. Patterson, B. J. Shreeve, and B. A. Roberts, Zentalbl. Bakt., 1980, Suppl. 8, 321. 7y C. J. Mirocha, S. V. Pathre, and C . M. Christensen in 'Mycotoxic Fungi, Mycotoxins, Mycotoxicoses: an Encyclopedic Handbook', Vol. I, ed. T. D. Wyllie and L. G. Morehouse, Marcel Dekker Inc., New York and Basel. 1977, p. 365. 8o D. 1. Fennell, R. J. Bothast, E. B. Lillehoj, and R. E. Peterson, Cereal Chem., 1973, 50,404. E. B. Lillehoj and C. W. Hesseltine, in 'Mycotoxins in Human and Animal Health', ed. J. V. Rodricks, C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc., Park Forest South, Illinois, 1977, p. 107. L. J. Ashworth, J. L. McMeans, J. L. Pyle, C. M. Brown, J. W. Osgood, and R. Ponton, Phytoparho1og.v. 1968, 58, 102. 8 3 N. D. Davis and U. L. Diener, J. Appl. Biochem., 1979, I. 115. 84 N. D. Davis and U. L. Diener, J. Appl. Biochem.. 1979, 1. 123. 76

77

M y cotoxins

22 1

recommended in the book of AOAC official methods. Extraction and column chromatography steps are scaled down and by using layers of appropriate absorbents aflatoxin is trapped as a concentrated band on the minature column. Appropriate measurement is made by viewing in U.V.light and comparing with columns containing standard amounts of pure toxin. A similar method is available for ochratoxin A.68 Two recent developments have sped up and increased the reliability of quantitative t.1.c. analysis. First, column chromatography can be performed in a fraction of the usual time if commercially available chromatography cartridges attached to 25 ml glass syringes are used in place of conventional chromatography columns. As in the mini-column methods, small volumes of food or feedstuff extract are required and with the use of smaller quantities of eluting solvent, the analyst is exposed to less toxic solvent vapour. Secondly, many interfering substances can be distinguished from aflatoxin and other mycotoxins by using 2-dimensional t.l.c., which can now be carried out quickly and precisely with small (10 x 10 cm2) aluminium backed ready-spread silica chromatographic plates. With this technique as little as 0.01 pg aflatoxin B , kg-' has been detected in compounded animal feeds.85 Progressively smaller amounts of many mycotoxins are being measured and, for example, with laser fluorimetry as an h.p.1.c. detection system concentrations measured in pg kg-I would seem to be a possibility. However, little regard is paid to the need for high levels of sophistication. A brief consideration of sterigmatocystin will serve as an example. This is a biosynthetic precursor of aflatoxin B, but has an oral LD,, in the rat some 30 times larger.86p87It is found less often as a contaminant of animal feeds, is 125 times less effective than aflatoxin B in initiating bile-duct hyperplasia in a standard duckling bioassay and some 250 times less effective as a liver carcinogen.88 Analytical limits for the measurement of aflatoxin B , in most food and animal feedstuffs is about 10 pg kg-' 67 and from the above comparisons of toxicological potential it can be argued that the need is to detect 300-2500 pg sterigmatocystin kg-I, whereas several methods are currently available for the determination of sterigmatocystin in various foods with detection of 5-50 pg kg-',89790As in other fields of environmental toxicology trace mycotoxin analysis tends to become an end in itself.

5 Occurrence in Food and Animal Feed Contamination Resulting from Direct Fungal Attack.-The natural moulding of food has been discussed in an earlier section and Table 5 lists various foods that have been shown at one time or another to contain traces of mycotoxins. Cereals, nuts, and foods manufactured from them are especially susceptible. The same commodities form the basis of many animal feedstuffs, and from Table 6 it will be

'' B. A Roberts, E. M. Glancy, and D. S. P. Patterson. J. Assoc. OffAnal. Chem.. 1981. 64, 961. K. J. van der Watt, in 'Mycotoxins', ed. I . F. H. Purchase. Elsevier Scientific Publishing Co.. Amsterdam, Oxford, and New York, 1974, p. 369. E. B. Lillehoj and A. Ciegler, Mycopath. Mvcol. Appl., 1968, 35. 373. F. Dickens, H. E. H. Jones, and H. B. Waynforth, Br.J. Cancer. 1966,20, 134. 89 G. M. Shannon and 0. L. Shotwell, J . Assoc. OffAnal. Chem., 1976.59.963. 90 H. P. van Egmond, W. E. Paulsch, E. Deijill, and P. Schuller, .I. Assoc. Of Anal. Chem., 1980, 63,

86

110.

Eni7ironmental Chemistry

222

Table 5 The natural occurrence of mvcotoxins as contaminants of food and animal

feedingstufls

-

E

-

L

a x .-.

3

s z

+ +

Peanuts, groundnut meal Brazil nuts, pistachio nuts, pecans, almonds, walnuts, filberts Cotton seed Copra Various seed oils (unrefined only) Sorghum Barley Corn/Maize Oats RYe Rice Wheat Soya bean White, navy, field beans Coffee beans Peppers, spices Dried figs Apples, apple juice, pears, peaches, apricots, bananas, pineapple, grapes Dairy products: milk, cheese Pig meat Meat products: sausages Mixed animal feeds H aY Silage

+ + + + + +

+ + +

+ + +

+ +

+

+

+

+ +

+

+

+?

+

+

Data from, L. Stoloff, in 'Mycotoxins and Other Fungal Related Food Problems', ed. J. V. Rodricks, Adv. Chem. Ser., American Chemical Society, Washington D C , 1976, No. 149, p. 23; H. K. Frank, Ann. Nutr. Aliment., 1977. 31, 459; D. S. P. Patterson, B. A. Roberts, B. J. Shreeve, A. E. Wrathall, and M. Gitter, Ann. Nutr. Aliment., 1977, 31, 643; Anon., Food Surveillance Paper No. 4, 'Survey of Mycotoxins in the United Kingdom', H.M.S.O., London, 1980

Table 6 Mycotoxins in home grown cereals and animal feeds (based on observations made during 1966- 1979) Torn/ No. Home grown cereals Compound animal feeds Groundnut mealh Detection limits

523 8 12 31 ~

No. somples contaminated with mycoroxin"

AJlaloxin B , 3

Citrinin

Ochrnloxin A

Sterigmarocystin

I1

67 27

17

8

-

-

-

-

10

40

47

30

-

0.2

20

5

Zearalenone

( p g kg-')''

'Some samples were contaminated with more than one toxin: ' a component of compound animal feeds; approximate figures: limits vary with the type of feed analvsed Data from. A. E. Buckle, Pror. 2nd In!. Cortfr. Vet. Pharmrrcol. Toxicvl. Therap.. 1981. in press: D. S. P. Patterson and B. A. Roberts. Vet. Key., 1080. 107. 240

M-vcotoxins

223

seen that in the UK aflatoxin has recently been a common contaminant of groundnut meal, and ochratoxin A is an occasional contaminant of barley. Other my cotoxins have been found less frequently. Indirect Contamination of Food.-Mycotoxins present in animal feeds may appear as residues in the tissues and products of farm animals but, in general, concentrations are many times lower than in the feed. Indeed, farm animals behave as very effective filters for feed-borne mycotoxins. Aflatoxin will be used to illustrate this general principle of mycotoxin ‘carry-over’. So small is the degree of residue accumulation that with rations containing 300-500 pg aflatoxin B, kg--’ it has been found that pigs had to be fed this diet for 17 weeks or longer before measurable amounts of aflatoxin B , could be found in the meat.91 Furthermore, the toxic diet induced such an erratic effect on the liver, that by no means all were condemned at routine meat inspection and of those that were acceptable to the Meat Inspector not all were found to contain aflatoxin B , on chemical analysis. In this experiment, the levels of aflatoxin were far in excess of those permitted by current UK Fertilisers and Feeding Stuffs regulation^.^^ The proportion of dietary aflatoxin B, ‘carried-over’ into meat and liver of cattle has been estimated to be about 0.1 and 0.3%, respectivelyY2with similar quantities of aflatoxin M I detectable. Only with aflatoxin B , at dietary concentrations of at least 1-2 pg g-l could residues be detected that were in excess of West German tolerances for food (10 pg total aflatoxins kg-’, 5 pg aflatoxin B, kg-l). The hen seems to be an even better filter for dietary aflatoxin than large farm animals. Thus aflatoxin residues have been only detectable in hens eggs when dietary levels of 3-4 pg aflatoxin B, g-’ (white and brown laying birds) were reached and corresponding maximum concentrations in the eggs were only 0.4 and 0.2 pg kg-1.93 Aflatoxin is readily transferred to cows’ milk predominantly in the form of aflatoxin M, and it has been shown that its concentration in milk is directly related to the daily dietary intake of aflatoxin B,.94-96Levels of milk contamination can be predicted from a detailed knowledge of dietary aflatoxin intakes, but alternatively it has been shown that the concentration of aflatoxin M, in milk is very approximately a 300th of the concentration of aflatoxin B, in a dairy ration.97 This approximation takes no account of breed differences, stages of lactation, milk yield, etc., but it has been used98 to demonstrate that with current regulations governing aflatoxin B contamination in animal feeds,74the maximum expected concentration of aflatoxin M, in milk would be around 0.1 pg I-,,

,

P. Krogh, B. Hald, E. Hasselager, A. Madsen, H. P. Mortensen, A. E. Larsen, and A. D. Campbell, Pure Appl. Chem., 1973,35,275. ’*R. Loetzsch and L. Leistner, Chem. Abstr., 1975, 85, 158 076; Proc. In(. Conf. Mycotoxins, Munich, 1978, p. 32. 9 3 R. Loetzsch and L. Leistner, Fleischwirtschafi, 1976, 56, 1777. 94 I . F. H. Purchase, Food Cosmet. Toxicol., 1972, 10,53 1. 95 F. Kiermeier, Pure Appl. Chem., 1973, 35, 271. y6 D. S. P. Patterson, in ‘Mycotoxic Fungi, Mycotoxins, Mycotoxicoses: an Encyclopedic Handbook’, Vol. 1, ed. T. D. Wyllie and L. G. Morehouse, Marcel Dekker Inc., New York and Basel, 1977, p. 159. 97J. V. Rodricks and L. Stoloff, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks, C. W. Hesseltine, and M. A. Mehlman. Pathotox Publishers Inc., Park Forest South, Illinois, 1977, p. 67. y8 B. J. Shreeve, D. S. P. Patterson, and B. A. Roberts. Food Cosmef. Toxicol., 1979, 17, 15 1. 9*

224

Environmental Chemistry

a figure which compared very favourably with observed v a l ~ e s and ~ ~ is, ~ ~ ~ ~ much lower than the tolerances for aflatoxin B, in human food of about 5 pg kg-I set by law in certain Western countries.99 With the food industry’s increasing awareness of the mycotoxin problem, the introduction of tolerances and our natural reluctance to eat obviously mouldy food, there is only a slight risk of acute aflatoxin poisoning due to high levels of aflatoxin in nuts, nut products, and similar foods. The indirect contamination of milk is different in that milk in one form or another is such a constant part of man’s diet, especially that of infants. And, although levels of aflatoxin M, in milk are low (sub-micrograms l-’), it obviously constitutes a significant form of chronic exposure. There is an epidemiologically demonstrable association between dietary aflatoxin and the risk of developing liver cancer49~so~100 and so chronic human exposure should be kept to an absolute minimum.50In the case of milk this has been done by reducing levels of aflatoxin B, in the rations of dairy COWS'^*^^ and also by choosing ‘action levels’ for aflatoxin M , in milk (e.g., 0.5 ,ug 1-’ in the United States).

6 Metabolism and Mode of Action of Mycotoxins Twenty years after its discovery, the relationship between aflatoxin metabolism and its toxic action is still being explored and in the case of the other toxins known occasionally to be present in animal feedstuffs in the UK very little is known of this aspect of metabolism. Several reviewers93.lo*-’ l o have considered the relationships between the metabolism of aflatoxin, sterigmatocystin, ochratoxin A, and Fusarium toxins (trichothecenes and zearalenone), their toxicology, their mode of action, and their potential for accumulating toxic residues in animal tissues. A brief account of this topic follows and, although some recent or important references are listed, many more referring to original work are to be found in the reviews cited above. Metabolic pathways for 10 mycotoxins have been summarized in Table 7. Metabolic Activation and Detoxification.-Like other xenobiotics, mycotoxins may be metabolized to physiologically inactive or more readily excreted molecules, usually by the hepatic mixed-function oxidases, in a process of detoxification. Alternatively they may be ‘activated’ by conversion to highly reactive derivatives, P. Krogh, Pure Appl. Chem., 1977.49. 17 19. F. G. Peers. Zentralbl. Bakt., 1980, Suppl. 8. 279. Anon., Food Chem. News, 1977, 19.38. lo‘ D. S. P. Patterson, Food Cosmet. Toxicol., 1973. 11. 287. lo’ D. S. P. Patterson, Cah. Nutr. Dietet.. 1976. Suppl. 2. 71. I o 4 D. S. P. Patterson, Pure Appl. Chem., 1977, 49. 1723. lo‘ D. S. P. Patterson, in ‘Mycotoxins and Liver Injury’. ed. T. F. Slater. Academic Press, London and New York, 1978, p. 403. I”‘ D. S. P. Patterson, in ‘Natural Toxins’, ed. D. Eaker and T. Wadstrom. Pergamon Press, Oxford and New York. 1980. p. 681. lo’ Y. Ueno, Proc. Jpn. Assoc. Mycotoxicol., 1976. No. 314, 25. lo* Y. Ueno, Pure Appl. Chem., 1977,49, 1737. j o y D. P. H. Hsieh. Z. A. Wong, J. J. Wong, C. Michas, and R. H. Ruebner, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks, C. W. Hesseltine. and M. A. Mehlman, Pathotox Publishers Jnc., Park Forest South. Illinois, 1977. p. 37. ’ l o T. C. Campbell. in ‘Mycotoxins in Human and Animal Health’, ed. J. V . Rodricks. C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc.. Park Forest South, Illinois. 1977. p. 687. 99

loo

-+

-+

-+

-+

-+

-+

-+

-+

-+

+ aflatoxin M, 4-hydroxy lation aflatoxin P, 0-demethylation 22-hydroxylation (cyclopentenone aflatoxin Q, ring) corresponding glucuronides conjugation of aflatoxins M,, P , , Q, + glutathione conjugate conjugation of 2,3-oxide + aflatoxicol (reversible reaction: also cyclopentenone reduction (cytosol aflatoxin Q, aflatoxicol H , ) and microsomal dehydrogenase) - as for aflatoxin B, except for activation reaction ? 2,3-dehydrogenation aflatoxin B, - as for aflatoxin B, except for reactions involving the cyclopentenone moiety - see remarks under aflatoxins B, and G, - as for aflatoxin B, except for 4-hydroxylation 0-demethylation demethyl sterigmatocystin conjugation glucuronide phenylalanine + dihydroisohydrolysis (carboxypeptidase A) coumaric acid (ochratoxin a) -+ 4-hydroxyochratoxin A h ydrox ylation none defined hydrolysis (p-acetyl) + HT2-toxin (P-hydroxyl) glutathione conjugate conjugation (cytosol transferase) NADP/NADP linked dehydrogenases -+ several reduced forms of (cytosol enzymes) ? conjugation zearalenone reactions

DetoxiJcation path wavs"

rnicrosomal enzymes except where stated; by analogy with aflatoxin B,

Zearalenone

Patulin T-2 toxin

Ochratoxin A

Aflatoxin G, Aflatoxin G, Aflatoxin M, Sterigmatocy stin

Aflatoxin B,

Aflatoxin B,

Mycotoxin ( f o r structural formula, see Figure 2 )

Table 7 Metabolism of mycotoxins: detoxijication and activation in the liver

zearalenol may be an 'active' metabolite

none known none known

none known

for aflatoxin B, none possible - as for aflatoxin B I b oxidation + 2,3-oxideb - as

none possible

dihydrodiol (? acute toxicity)

1

oxidation + 2,3-oxide (chronic effects)

Activation reactiona

z

0

2.3 oxid.

B2

a] a 1

B1

conjugated with glutathione or metabolized to the 2,3-dihydrodiol ( 3 ) . A t physiological p H the dihydrodiol rearranges to a dialdehyde, which forms Schiff bases with primary amino-groups of protein molecules (4). Aflatoxin B,, (herniacetal),produced by reacting aflatoxin B with dilute mineral acid (9, is a model compound ( 6 ) (see also Figure 6). Hydroxylated metabolites (7-9) are also formed, bv mixedfunction oxidases. Other hydroxylated metabolites (aflatoxicol and the analogue, H I )f o r m reversibly in reactions catalped by NADP-dependent cytoplasmic and microsomal dehydrogenases. Aflatoxin B, may be converted to aflatoxin B, (1 l), but is otherwise metabolized bypathways 7-10

Figure 4 Pathwaysfor the metabolism of afatoxin B, in the liver. AJatoxin 2,s-oxide isformed by microsornal enzymes (1). It alkjdates D N A (2). may be

D N A odduct

Dihydrodiol

it4-vcotoxins

227

which then interact with functional macromolecules (often DNA) at specific locations in the target organ. On the basis of our present knowledge it is believed that only mutagenic and carcinogenic mycotoxins undergo metabolic activation as well as detoxification (see Table 7, adapted from ref. 105). The precise outcome of ingesting my cotoxin is highly species dependent because comparative studies show that metabolic pathways are developed to varying extent in different animal species.

Reactive Toxin Molecules.-AJatoxin and Related Compounds. The metabolism of aflatoxin B , is summarized in Figure 4. Metabolic activation for aflatoxin B, has been inferred from the fact that this toxin is a potent carcinogen and that it becomes a bacterial mutagen in vitro only after prior incubation with a preparation with liver microsomes. By analogy with the carcinogenic polycyclic hydrocarbons, it was therefore proposed that the mutagenic and presumably the carcinogenic properties of aflatoxin B, involved its prior conversion to the 2,3-oxide after which it exerted these effects by alkylating DNA molecules of bacterial or liver cells. There is experimental evidence for the covalent attachment of labelled aflatoxin molecules to DNA in vitro and in vivo. Thus, aflatoxin 2,3-dihydrodiol, presumably a metabolite of the 2,3-oxide, has been isolated from liver microsome preparations incubated with aflatoxin and DNA and from liver tissues of dosed experimental animals (see Figure 5). Synthetic aflatoxin 2,3-dichloride has been used as a model compound for the epoxide, which is probably very reactive, may have only a transient existence, and has not yet been isolated or detected directly. The 2,3-vinyl ether double bond also occurs in the molecular structures of aflatoxin G I and M, and sterigmatocystin besides several other related compounds and metabolic activation similar to that described for aflatoxin B, is at least A f l o t o x i n B , dlhydrodiol

1lT-p Aflotoxin B ,

2.3

+

DNA

' o

oxide /

other products

Figure 5 Aflatoxin B , 2,3-oxide (the activated form of aflatoxin, shown as its partial

structure) alkylates DNA to form a N1-guanyl derivative. On acid hydrolysis or spontaneously in the liver, the DNA adduct breaks down to form ajlatoxin B, 2,3-dihydrodiol and DNA. Other less important reactions give rise to aguanic DNA amongst other products (after Tzu-chien V. Wang, and P. Cerutti, Biochemistry, 1980, 19, 1962). Formation of the dihydrodiol is a well developed merabolic pathway in livers of animal species that are particularly susceptible to acute ajlatoxin poisoning (G. E. Neal. D. J. Judah, F. Stirpe, and D. S. P. Patterson, Toxicol. Appl. Pharrnacol., 1981, 58,431)

HO

(A,,

363m)

resonance forms of Bza phenokik ion ( Amax approx. 400rwn )

OHC

Figure 6 Rearrangement of the aflatoxin B,, molecule and its reaction with amino-acids (after A. E. Pohland, M. E. Cushmac, and P. J. Andrellos, J . Assoc. Ofl. Anal. Chem., 1968, 5 1,907). Afi’atoxin B , 2,3-dihydrodiolis believed to react similarly

oflatoxm herniacetal or BzO

amino acids and proteins

pH74

at

or above

OHC

Schiff base

My cotoxins

229

theoretically possible. The fact that aflatoxin G , and M I and sterigmatocystin are reactive in the Ames test for bacterial mutagens'' supports the proposition that these toxins are also activated to the respective 2,3-oxides (Table 8). The conversion by the liver of a high proportion of incoming aflatoxin B, molecules to its 2,3-dihydrodiol appears to be a characteristic of animal species that are highly susceptible to acute aflatoxin poisoning and it is probable that in this form it interacts with key enzymes leading to hepatocellular necrosis. Thus, at physiological pH, the hemiacetal rearranges to the resonant hybrids of a dialdehydic phenolate ion when it can react with amino-acids and proteins including enzymes to form Schiff bases (see Figure 6). In particular, it has recently been shown that aflatoxin 2,3-dihydrodiol inhibits protein synthesis in uitro. l 1 Aflatoxin B2a, the hemiacetal of aflatoxin B,, is formed by the acid-catalysed addition of water across the isolated vinyl ether double bond and with a structure closely related to that of the 2,3-dihydrodiol (see Figures 4 and 6) its chemical properties are also similar. In particular, it also undergoes rearrangement to the corresponding dialdehyde at pH 7 and above, has an u.v.-absorption spectrum identical to that of the dihydrodio1112and is thought to react with primary amines and proteins to form Schiff bases. For this reason, in the early 1970's it had been incorrectly concluded from in vitro metabolism studies that the hemiacetal was a major metabolic product of certain animal species'02 and that its role in the pathogenesis of acute liver necrosis was that now ascribed to the dihydrodiol."' Only recently has this rather confusing aspect of aflatoxin metabolism been resolved owing to the discovery that tris[ (hydroxymethy1)aminomethanel derivatives of the two compounds could be separated readily by an h.p.1.c. m e t h ~ d . ~ ~ ' * ~ ~ ~ The unchanged aflatoxin B molecule is probably also intrinsically reactive. Thus, probably by virtue of its coumarin-type structure it inhibits the synthesis of vitamin K-dependent blood-coagulation factors, and in addition it behaves as a pseudosteroid reacting with steroid-binding sites on the hepatic endoplasmic reticulum and the soluble 17-hydroxysteroid dehydrogenase of the liver cytoplasm.

Ochratoxin A . The two known routes for the metabolism of ochratoxin A (see Table 7 ) lead to a loss of toxicity and it is therefore probable that the unchanged toxin is the reactive molecular species. Other than determining its propensity for protein binding, the mode of action at the molecular level has not been studied although it is known that the site of toxin action in the kidney is remarkably specific, being confined to the proximal tubules. T2-toxin and Related Trichothecenes. Little is known of the mode of action of the trichothecene mycotoxins in vivo although T2-toxin is an inhibitor of protein synthesis in vitro and its ingestion causes a sub-optimal production of blood coagulation factors in avian liver. Based on the clinical course of ATA and a similar disease experimentally reproduced in the cat, it is believed to have an affinity for the bone marrow. Trichothecenes applied topically to the skin cause a severe necrotic reaction but when the 12,13-epoxide group (Figure 2) is selectively destroyed (e.g., Ill

'Iz 'I3

G. E. Neal, D. J . Judah, F. Stirpe, and D. S. P. Patterson, Toxicol.Appl. Pharmacol., 198 1, 58,431 D. H. Swenson, J. A. Miller, and E. C. Miller, Biochem. Biophys. Res. Cornrnun., 1973,53, 1260. G. E. Neal and P. J. Colley, Biochern.J . , 1978, 174,839.

E nu ironmenta 1 Chem istry

230

by reduction with lithum aluminium hydride) they are no longer reactive. It is for this reason that it is believed that the epoxide group of the unchanged molecule is the probable reactive site. Zearalenone. Assayed biologically in immature female mice this mycotoxin and its reduction products are oestrogenic but much less so than oestradiol or the synthetic diethylstilboestrol. One such product, zearalanol (9,lO double bond and the 6-0x0 group of the undecenyl ring are reduced; see Figure 2) is a permitted growth promotant for livestock. a-Hydroxysteroid dehydrogenase, an enzyme contained in the cytosol of hepatic cells, is able to catalyse the reduction of zearalenone to the corresponding alcohol, zearalenol (only the 6-0x0 group reduced) and other active metabolite^.^^^^"^ Thus, with a steroid-metabolizing pathway implicated, it is possible that zearalenone interacts with target cells (e.g., in the uterus) in that form. Metabolism and Toxic Residues.-Residues of mycotoxins appear in animal tissues and their products but, although a steady state is reached in a few days, at least in the case of aflatoxin they do not seem to accumulate. From Table 8 it can be seen that all the metabolites of aflatoxin B , are less toxic than the parent toxin measured in terms of LD,, values for day-old ducklings or chick embryos. Several of these metabolites retain the important 2,3-vinyl ether grouping, however, and are therefore potentially carcinogenic. But aflatoxin M the only metabolite so far tested is still somewhat less potent than aflatoxin B , . The activated forms of Table 8 Acute toxicities of aflatoxin B , and its metabolites AJatoxin Bl

MI PI Ql

Aflatoxicol Aflatoxicol H I

B,, (hemiacetal) 2,3-oxide (epoxide)

Type of metabolite (parent toxin)

Toxicity relative to BIa 100

72b formed by liver microsomal enzymes reduction products of microsomal and cytosol deh ydrogenases model compound for the dihydrodiol 'activated metabolite' formed by liver microsomal enzymes

v. low" 5d

6e v. lowf v.

IOWK

presumably a transient metabolite

Calculated from toxicity data given in the respective references; * LD,, determined in day-old duckling: value for aflatoxin B , about 0.3 mg kg-I body wt, C. W. Holzapfel, P. S. Steyn, and I. F. H. Purchase, Tetrahedron Lett., 1966, 2799; 'Chick embryo LD,,, L. Stoloff, M. J . Verrett, J . Dantzman, and E. F. Reynoldo. Toxicol. Appl. Pharmacol.. 1972. 23. 528: Chick embryo LD,,, D. P. H. Hsieh, A. S. Salhab, J. J. Wong, and S. L. Yang, Toxicol. Appl. Pharmacol.. 1974, 30, 231; Bile-duct hyperplasia assay, day-old duckling, R. W. Detroy and C. W. Hesseltine, Nature (London), 1968. 219, 967: /Chick embryo LD,,, A. S. Salhab and D. P. H. Hsieh, Res. Commun. Chem. Pathol. Pharmacol., 1975, 10, 419; a Bile-duct hyperplasia assay, day-old duckling, E. B. Lillehoj and A. Ciegler. Appl. Microbiol.. 1969, 17. 5 16

'I4

'I5

F. Tashiro. Y. Kawabata, M . Naoi. and Y. Ueno. Zentralbl. Bakt.. 1980, Suppl. 8. 3 1 I . M. Olsen, H. Pettersson. and K.-H. Kiessling. Toxicon, 1979. Suppl. I , 134.

23 1

Mycotoxins

aflatoxin do not present a residue problem at all as they are incapable of further activity after interaction with protein or DNA. Consequently, apart from the unchanged aflatoxin B , , the sole problem would appear to arise from residues of aflatoxin M , in the tissues and milk of farm animals. Similar considerations would apply to other mycotoxins and their metabolites but relevant data is scarce. 7 Control of Mycotoxins in the Food Chain

General.-Four types of control have received attention in recent years:’ 1 6 - ’ l 9 (1) prevention of fungal infection in the crops, (2) prevention of moulding during storage, (3) selection of shipments with minimal mycotoxin contamination, and (4) decontamination of commodities containing mycotoxins (see Figure 3). Control of Fungal Infection.-For many years aflatoxin contamination was thought to result from bad storage. This is still true but it has gradually become apparent that pre-harvest contamination also occurs. In corn and peanuts, for example, fungal infection of this kind may be largely unavoidable. Early studies of the post-harvest problems centred on the control of the environment and the use of antifungal agents during storage. But emphasis is now placed on good farm practice generally.l18 This includes insect control 120 because damage caused by insects is a major predisposing factor, the prompt harvesting of crops at maturity, and the use of cultivars of food plants’21*’22 that tend to resist insect damage and fungal infection. It is also sensible to segregate evidently mouldy crops to avoid the further spread of contamination during storage. Control by Selection.-Mycotoxin contamination commonly occurs in food or feed commodities imported from tropical or sub-tropical countries and whenever a choice can be made it is clearly desirable to use shipments with little or no contamination. Selection can be voluntary as for example where compounders of animal feeds follow an established ‘code of practice’123or adhere to official guideline^'.'^^ It can also be compulsory and in many countries the use of

L. A. Goldblatt and F. G. Dollear, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks. C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc.. Park Forest South. Illinois, 1977, p. 139. 11’ L. A. Goldblatt and F. G . Dollear, Pure Appl. Chem., 1977, 49, 1759. 118 L. A. Goldblatt and F. G. Dollear, in ‘Interactions of Mycotoxins in Animal Production’. Proc. Symp. 13 July 1978 Michigan State Univ., National Academy Sciences, Washington DC. 1979, p. 167. ‘I9 K . Aibara and N. Yano, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks, C. W. Hesseltine. and M. A. Mehlman, Pathotox Publishers Inc., Park Forest South, Illinois, 1977. p. 151. I2O E. B. Lillehoj, W. F. Kwolek, A. Manwiller, J. A. D u Rant, J. C. La Prade. E. S. Horner, J. Reid, and M. S. Zuber, Crop Sci., 1976. 16,483. A. C. Mixon, in ‘Mycotoxins in Human and Animal Health’, ed. J. V. Rodricks, C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc., Park Forest South, Illinois, 1977, p. 163. 122 M. S. Zuber, in ‘Mycotoxins in Human and Animal Health’, ed. J. V . Rodricks, C. W. Hesseltine, and M. A. Mehlman, Pathotox Publishers Inc., Park Forest South, Illinois, 1977, p. 173. 1 2 3 Anon., Report, Interdepartmental Working Party ‘Toxicity associated with certain samples of groundnuts’, 1962, p. 21 (cited by P. K. C . Austwick, p. 296 in Vol. 2, ref. 9). 124 J . V. Rodricks and H. R. Roberts. in ’Mycotoxins in Human and Animal Health’. ed. J . V. Rodricks, C. W. Hesseltine. and M. A. Mehlman, Pathotox Publishers Inc.. Park Forest South. Illinois. 1977, p. 753. II6

Environmental Chemistry

23 2

aflatoxin-contaminated food or feed commodities is restricted by statutory

regulation^.^^

3”

Effective selection is necessarily dependent on reliable chemical analysis and methods of sampling, screening, and rapid aflatoxin or ochratoxin analysis have already been referred to (see also ref. 125).

,

Detoxification of Aflatoxin.-Heat treatment and various reactions of aflatoxin B with common laboratory reagents have been studied with a view to developing methods for the decontamination of aflatoxin contaminated commodities. Thus, aflatoxin B, has been found to be stable to heat in the dry state up to its melting point (268-269 OC),ll* but in the presence of moisture the lactone moiety of the molecule probably opens and the o-coumaric acid so formed may subsequently undergo decarboxylation.’26 Hydrolysis of the lactone ring occurs in alkaline At elevated temperatures solution but aflatoxin B reforms on a~idificati0n.l~~ (about 100 O C) irreversible changes occur with ring-opening, decarboxylation, and loss of the single methoxy group from the aromatic ring.12*Similar reactions occur with ammonia (gaseous or aqueous) and certain amines to form products with much lower toxicity compared with the parent toxin. 1 2 9 , 1 3 0 In the presence of mineral acid, water is added across the biologically active vinyl ether double bond of aflatoxins B, or G, to form the corresponding relatively non-toxic hemiacetals, B,, and H2,.13141 3 * Destruction of aflatoxin is achieved by the addition of various oxidizing agents and for example, sodium hypochlorite is widely used to decontaminate laboratory glassware used for aflatoxin or other mycotoxin analyses. l 3 Aflatoxins B, and G , are also degraded by U.V.radiation134and this is readily observed when the toxins are absorbed onto the silica of a t.1.c. plate. The hemiacetal or their alkoxy-derivatives are formed when aflatoxins B , and G, are irradiated in phosphate buffer or in alcoholic s o l ~ t i o n . ~ Dry ~ ~films - ~ ~of~aflatoxin B, are resistant to gamma radiation but destruction has been observed when the toxin was dissolved in chloroform and particularly in water.13*

,

B. Lillehoj. in ‘Interactions of Mycotoxins in Animal Production’. Proc. Symp. 13 July 1978. Michigan State Univ., National Academy of Sciences, Washington DC, 1979, p. 139. I26 T. J. Coomes, P. C. Crowther, A. J. Feuell. and B. J. Francis, Nature (London). 1966, 209,406. 12’ J. de Iongh. R. K. Beerthuis, R. 0. Vles, C. B. Barrett, and W. 0. Ord. Biochim. Biophjs. Acta, 1962, 65, 548. 12’ F. Kiermeier and L. Ruffer, Z . Lebensm. (Inters.Forsch., 1974, 155, 129. Iz9 R. F. Vesonder. A. C. Beckwith, A. Ciegler, and R. J. Dimler, J . Agric. Food Chem.. 1975, 23. 242. I3O L. S. Lee, J. B. Stanley. A. F. Cucullu. W. A. Pons, and L. A. Goldblatt, J . Assoc. Of( Anal. Chem., 1974, 57,626. 1 3 ’ A. E. Pohland, M. E. Cushrnac, and P. J. Andrellos, J . Assoc. 08 Anal. Chem., 1968, 51.907. 1 3 * A. Ciegler and R. E. Peterson, Appl. Microbial.. 1968, 16,665. 13’ L. Stoloff and W. Trager, J . Assoc. OffAnal. Chem., 1965.48.681. 134 P. J. Andrellos, A. C . Beckwith. and R. M . Eppley, J . Assoc. OffAnal. Chem., 1967. 50, 346. 135 D. A. Lillard and R. S. Lantin, J . Assoc. Off: Anal. Chem., 1970, 53. 1060. 1 3 6 A. C. Waiss and M. Wiley. J. Chem. Soc., Chem. Commun.. 1969. 5 12. 1 3 ’ R.-D. Wei and F. S. Chu. J . Assoc. Off Anal. Chem.. 1973. 56. 1425. H. K. Frank and T. Grunewald, Food Irrad., 1970, 11, 15. ‘I5 E.

M y cotoxins

233

Promising Decontamination Processes.-Aflatoxin residues are reduced considerably by roasting peanuts,’39 pecans,*4ocorn (maize) and oil-seed residues14* and the toxin is removed from vegetable oils during normal refining processes since it is concentrated in the soap More than 60 chemical treatments have been screened for decontaminating animal feeds mainly involving alkalis. 144 Ammonia gas provides the most promising treatment as indicated by chemical analysis and livestock feeding trials with ammoniated corn, cotton seed, and groundnut meals.11s,145, 146 Accordingly, ammoniation plants are beginning to operate commercially in some parts of the world. Mycotoxins other than Aflatoxia-As sterigmatocystin is structurally closely related to aflatoxin it is therefore likely to respond to similar detoxification procedures. Although other mycotoxins are destroyed by strong oxidizing agents there have been no comparable decontamination studies. Good husbandry and careful storage of food or feed crops are the two basic means available for the control of mycotoxins generally.

L. S. Lee, A. F. Cucullu, A. 0. Franz. and W. A. Pons, J . Agric. Food Chem., 1969, 17.451. F. E. Escher, P. E. Koehler, and J. C. Ayres, J. Food Sci., 1973, 38, 889. 14‘ H. F. Conway, R. A. Anderson, and E. B. Bagley, Cereal Chem.. 1978. 5 5 . 1 15. 14* G. E. Mann, L. P. Codifer, and F. G. Dollear. J. Agric. Food Chem., 1967. 15. 1090. 14’ W. A. Parker and D. Melnick, J. Am. Oil Chem. SOC.,1966. 43,635. 144 G. E. Mann, L. P. Codifer, H. K. Gardiner. S. P. Koltun. and F. G. Dollear, J. Am. O il Chem. SOC., 1970, 47, 173. 145 H. K. Gardiner, S. P. Koltun, F. G. Dollear, and E. T. Rayner, J . A m . Oil Chem. Soc., 1971. 48, 70. 146 A. C. Key1 and W. P. Norred. in ‘Interactions of Mycotoxins in Animal Production’, Proc. Symp. 13 July 1978, Michigan State Univ., National Academy of Sciences. Washington DC, 1979, p. 185.

139 I4O

5 Occurrence, Distribution, and Chemical Speciation of Some Minor Dissolved Constituents in Ocean Waters BY J. D. BURTON AND P. J. STATHAM

1 Introduction

Since Brewer’ reviewed the topic of the minor elements in sea water there has been a great advance in accurate determination of many of these elements and, related to this, in our knowledge of their occurrence and distribution in the ocean. The inadequacies of the data available by the mid 1970s have been discussed by Brewer and Spencer.* Subsequent work has confirmed that many previous studies on commonly determined elements were invalidated by errors, mainly due to contamination, in sampling or analysis; for some elements much of the literature must now be regarded as a record of analytical noise. This review deals primarily with advances, since Brewer’s account, in knowledge of the dissolved minor elements ( i e . , those occurring at concentrations below 1 mg 1-l) in oceanic waters, excluding radioactive nuclides and the principal micronutrient elements (nitrogen, phosphorus, and silicon). Work on particulates and processes at the ocean boundaries has not been included, unless particularly relevant to the main theme. This applies also to studies of the composition of coastal and estuarine waters, and partially enclosed seas, which are in many cases influenced by local factors and for which there is often considerable uncertainty still regarding the comparability of analytical data. For oceanic waters there are now reasonably objective criteria by which to assess the quality of data on the basis of either the compatibility of observations with known oceanographic phenomena, or by the analytical agreement between laboratories and between different methods of determination. Studies of chemical speciation have been included in the review where they relate to open ocean waters. Earlier work on this topic was discussed by Stumm and B r a ~ n e r Various .~ aspects of the marine geochemistry of the minor

I

P. G. Brewer, in ‘Chemical Oceanography’, 2nd Edn., ed. J. P. Riley and G. Skirrow, Academic Press, London, 1975, Vol. 1, pp. 4 1 5 4 9 6 . P. G. Brewer and D. W. Spencer, in ‘Marine Chemistry in the Coastal Environment’, ed. T. M. Church, American Chemical Society, Washington DC, 1975, pp. 80-96. W. Stumm and P. A. Brauner, in ‘Chemical Oceanography’, 2nd Edn. ed. J. P. Riley and G. Skirrow, Academic Press. London, 1975, Vol. 1, pp. 173-239.

234

Constituents in Ocean Waters

235

elements that are not discussed here have been covered in recent reviews on suspended material,4 the air-sea i n t e r f a ~ e and , ~ estuarine processes.6 Workers studying the distributions of trace elements in oceanic waters have adopted various approaches as regards the initial treatment of samples. Some analyses have been made on filtered samples, usually employing filtration with nominal pore diameters of 0.4 or 0.45 pm, which is the conventional operational basis for distinguishing particulate and dissolved fractions. Other measurements have been made on unfiltered samples: for most elements in the open ocean the contributions made to these analyses by particulate fractions can be considered negligible and the values regarded as characterizing the dissolved fraction. In a few cases the analyses represent the dissolved material following acidification, i.e. that which was in solution in the original sample together with that released from particulates at low pH. Attention has been drawn to such differences in treatment only when it seems that they are of possible significance in relation to the interpretation of the results. Various units are used for reporting concentrations of elements in sea water. Reported values have been converted here to sub-units of either mol kg-' or mol I-'. The individual elements are considered in the periodic order adopted by Brewer.'

2 Individual Elements Caesium.-Measurements' of caesium in waters from various depths in the northeastern Pacific Ocean emphasize the nearly conservative behaviour of the element but suggest a significant although small trend with changing depth. In surface waters the concentration, normalized to a salinity of 35%, was 2.25 nmol km showed a ratio of kg-', whereas samples collected at depths from 1-4 concentration of caesium t o salinity that was 1.4% lower. Barium.-Barium has continued to receive attention mainly because of its close chemical similarity t o 226Ra,which is of interest as a tracer for water mixing and circulation. The need to understand the influence of particulate transfer on the distribution of radium has led to especial interest in the degree of geochemical coherence of the two elements and in their transport with biogenous particles from surface to deeper waters and the regenerative cycles of biological material. Measurements have been reported* for barium in two profiles in the IndianAntarctic Ocean, one north and one south of the Antarctic Convergence. North of the Convergence the concentrations increased from 54 nmol kg-' at the surface to 105 nmol kg-' at 3704 m. South of the Convergence the surface concentration was considerably higher (75 nmol kg-I) as a result of upwelling of deep water in the circumpolar region. The concentrations of barium showed a close linear correlation with those of 226Ra.Calculations using a two-box mixing model suggested that, in 4 D . Lal, Science, 1977, 198, 997; W. M . Sackett in 'Chemical Oceanography'. 2nd Edn., ed. J . P. Riley and R. Chester, Academic Press, London, 1978, Vol. 7, pp. 127-172. R. A. Duce and E. J. Hoffman. Annu. Rev. Earth Planet. Sci., 1976. 4. 187. ti S. R. Aston, in 'Chemical Oceanography'. 2nd Edn., ed. J . P. Riley and R. Chester. Academic Press. London, 1978. Vol. 7, pp. 3 6 1 4 4 0 : E. Olausson and I. C a t 0 (ed.). 'Chemistry and Biogeochemistry of Estuaries'. Wiley, C hichester. 1980. 452 pp. ' T. R. Folsom, Nature (London), 1974. 248. 2 16. ' Y. H.Li, T. L. Ku, G . G . Mathieu. and K . Wolgemuth. Earrh Planet. Sci. Lett.. 1973. 19, 352.

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Environmental Chemistry

the world ocean, about 85% of the barium transported with the particulate flux from surface to deeper waters is recycled. Chung9 examined the data on barium and 226Rafor Antarctic and Pacific waters and concluded that their concentrations are not linearly correlated overall. The results indicate a tendency for the ratio of 226Rato barium to increase from surface water to bottom water. This reflects the differences in input mechanisms for the elements, 226Rabeing supplied dominantly by release from sediments, whereas this route is minor for barium.8 An examinationlo of data for GEOSECS stations in the Atlantic and Pacific Ocean showed a similar effect in the North Pacific. With the N

Figure 1 Distribution of barium, in a north-south section in the western Atlantic Ocean, based on nine vertical projiles. Isolines show concentrations of barium (nmol kg-' ).

(Redrawn from a figure in Deep-sea Res., 1977, 24,613; with permission of Pergamon Press Ltd.)

exception of this region, and possibly the Cape Basin, there was, however, a linear correlation of 226Raand barium at all stations, within the analytical uncertainties. The slope of this relationship was about 4.6 nmol 22hRaper mol Ba and there was an intercept for zero concentration of 226Racorresponding to about 4 nmol Ba kg-'. A more detailed analysis has been given" of the data from the Atlantic GEOSECS stations. Vertical profiles of barium closely resemble those of silicon and alkalinity. Nutrient-depleted surface waters contain 36-44 nmol kg-I, whereas the highest concentrations occurred in Antarctic Bottom Water which contained 100-106 nmol kg-I. The distribution for the Western Atlantic Ocean is shown in Figure 1. The dominant factors influencing this distribution are the physical circulation and the downwards transport of barium by biogenous particulate In

Y.X. Chung, Earth Planet. Sci.Lett., 1974, 23, 125. L. H. Chan, J . M. Edmond, R. F. Stallard, W. S. Broecker, Y.C. Chung, R. F. Weiss. and T. L. Ku, Earth Planet. Sci.Lett., 1976, 32 258. L. H. Chan, D. Drummond, J. M. Edmond. and B. Grant, Deep-sea Res., 1977, 24. 6 13.

Constituents in Ocean Waters

237

material. The data indicate that barium, like silicon, enters into a deep cycle of regeneration and dissolution, characteristic of skeletal components such as calcium carbonate and opal or other slowly dissolving mineral phases. Aluminium.-The operational definition of ‘dissolved’ fractions of aluminium based on membrane filtration may lead to uncertainty as to the forms included in this fraction in the case of fresh waters, but for a coastal sea water the concentration of the element in the filtrates has been shown1* not to differ significantly when the nominal pore diameter of the filter was varied over the range of 0.1-1.2 pm. In North Sea surface waters concentrations decrease away from the coast; l 2 the mean concentration for samples with salinities greater than 34Y& was 5 6 nmol I-’. Similar concentrations have been reported 3 , l 4 for the Mediterranean Sea. Mackenzie et aZ.13 reported, for a vertical profile near Corsica, a decrease from the surface concentration of ca. 90 nmol I-’ to a value of ca. 35 nmol 1-’ in the thermocline region, between 40-40 m, and a subsequent increase to ca. 185 nmol I-’ by 600 m; a significant correlation with silicon was observed. Caschetto and Wollast14 made seasonal observations in the same general area and found that in the upper 100 m, concentrations showed both temporal variations and variations with depth, usually in the range of 20-75 nmol 1-I. An increase in concentration with depth occurred, deeper waters characteristically containing about 150 nmol I-’. The distribution resembled that of silicon and inorganic combined nitrogen. In both accounts it was suggested that planktonic activity leading to uptake of aluminium and its removal from the euphotic zone was an important control on the concentration of dissolved aluminium. HydesIs has, however, emphasized the importance of inorganic processes in the control of aluminium concentrations in sea water. Although analyses on acidified stored GEOSECS samples showed essentially uniform distributions with depth, the data showed considerable scatter. A later profile in the North Atlantic, determined on unacidified samples, showed systematic trends with depth, with less scatter. Concentrations decreased from surface values of about 35 nmol I-l, to about 20 nmol I-’ at 1 km depth, followed by an increase to about 35 nmol l-l below 3.5 km. Concentrations of aluminium did not show a positive correlation with those of silicon. The absence of such a correlation was also indicated by the fact that the analyses on the GEOSECS samples, albeit showing unsatisfactory scatter, give lower values for the Pacific Ocean than the Atlantic Ocean. Somewhat similar values to those of HydeslL5but with some higher concentrations and irregular changes with depth, were reported for the Atlantic Ocean by Alberts et Experimental studies” have shown that the growth of a diatom in artificial sea water can reduce initial concentrations of added aluminium of up to 925 nmol1-l to (20 t- 20 nmol 1-’. Dissolution of aluminosilicates added to seawaterI8 yielded concentrations of 48-280 nmol 1-l, a higher range than is probable for open-ocean

’

l2

l3 l4

Is l6

D. J. Hydes and P. S. Liss. Estuarine Coastal Mar. Sci., 1977, 5, 755. F. T. Mackenzie, M. Stoffyn, and R. Wollast, Science, 1978, 199, 680. S. Caschetto and R. Wollast, Mar. Chem., 1979, 7 , 141. D. J . Hydes, Science.1979, 205, 1260. J. J. Alberts, D. E. Leyden, and T. A. Patterson. Mar. Chem., 1976. 4. 5 1. M. Stoffyn, Science, 1979. 203, 651. D. J. Hydes, Nature (London), 1977, 268, 136.

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surface waters. Higher concentrations were obtained in experiments in which aluminium was precipitated in sea water." Stoffyn l 7 considers that the concentration of dissolved aluminium in surface oceanic waters is less than would be expected on the basis of aluminosilicate interactions and stresses control by uptake into planktonic organisms, especially diatoms. Although some transport with biogenous particles must occur, the Atlantic Ocean profile reported by Hydes15 suggested that it may not dominate over other processes. He points out resemblances between that profile and some of the profiles reportedlo for copper in the Atlantic Ocean and discussed in a subsequent Section. He suggests that it may be generated by mechanisms similar to those proposed for copper, namely an atmospheric input to the surface waters, scavenging by particles at mid-depths, and an input from bottom sediments. On the basis of equilibrium calculations of the solubility of AI(OH),, Ahrland2' suggests that the concentration of dissolved aluminium found in seawater is consistent with its presence mainly as AI(0H);. There is uncertainty as to whether AI(0H); is a significant species. Thallium.-Recent measurements of dissolved thallium have been reported l2 only for near coastal waters but the samples included one of the surface seawater taken some 15 km from the New South Wales coast. This sample contained 65 pmol l-l, a value comparable to those found for inshore waters. Equilibrium calculations 22 suggest that the oxidation state in seawater should be dominantly T1"' with TI(0H); as the major species. Germanium.-A close linear correlation between concentrations of germanium and silicon has been reported23 for a profile in the northwestern Pacific Ocean. Concentrations of germanium increased from (5 pmol 1-' in surface waters to about 105 pmol I-' in deep water. The findings indicate the close involvement of germanium in the formation and dissolution of biogenous silica. Tin.-Concentrations of tin@) in near surface samples from Californian coastal pmol 1-'. There was no evidence for waters have been found2* to be 2.5-7 the presence of methylated tin compounds in these waters, although compounds that react with sodium borohydride to yield mono- and di-methyltin hydrides were detected in surface waters from San Diego Bay, that contained higher amounts of tin. Lead.-An investigation of the occurrence of lead in the northeastern Pacific Ocean has been undertaken by Schaule and Patterson. 2 5 * 2 6 Rigorous attention was given " J . D. Willey. Mar. Chem., 1975, 3, 227. E. A. Boyle. F. R. Sclater. and J. M. Edmond. Earth Planet. Sci.Lett., 1977, 37, 38. * I S. Ahrland. in 'The Nature of Seawater'. ed. E. D. Goldberg, Dahlem Konferenzen, Berlin. 1975. pp. I"

2 19-244.

G. E. Batlev and T. M . Florence. J . Electroanal. Chem. Inte~facialElectrochem., 1975. 61, 205. P. N. Froelich and M. 0. Andreae. Trans. A m . Geophys. Union. 1980. 61. 987 (Abstract). *'V. F. Hodge. S. L. Seidel. and E. D. Goldberg. Anal. Chem.. 1979, 5 1. 1256. '' B. Schaule and C. C. Patterson. in 'Lead in the Marine Environment'. ed. M. Branica and Z . Konrad. Pergamon Press. Oxford. 1980, pp. 3 1-43. 26 R. Schaulc and C. C. Patterson. Earlh Planet. Sci. Lett., 1981. 54. 97. 22

Constituents in Ocean Waters

239

to methods of collecting and analysing samples without significant contamination and the results supersede those from earlier studies, which gave substantially higher values. Concentrations in surface waters decreased in going from the mid-oceanic gyre region t o 200 km off the Californian coast, from 75-25 pmol kg-l; closer to shore concentrations generally increased again. The dominant supply of lead is atmospheric and the surface concentrations reflect this supply, the surface water movements, and the regionally variable efficiency of scavenging by particles,

Figure 2 Vertical distributions of dissolved (closed circles) and particulate (open circles) lead at a station in the central northeastern Pacific Ocean (32'41"' 145"OO'W). (Redrawn from a figure in 'Lead in the Marine Environment', ed. M. Branica and Z. Konrad, Pergamon Press, Oxford, 1980; with permission.)

including biogenous material, in the water column. The results for a vertical profile in the central ocean region are shown in Figure 2. Values for particulate lead are also shown as this becomes a substantial fraction of the total in deeper waters although amounting to 10% or less in most other samples. The concentration is fairly uniform from the surface to the thermocline region and then decreases markedly: deep water concentrations are as low as 5 pmol kg-I. This profile also reflects the atmospheric input, which is estimated to have been increased through anthropogenic mobilization t o about ten times the prehistoric oceanic input, with the result that the vertical distribution is probably not in a steady state. Schaule and

240

Environmental Chemistry

Patterson estimate the residence times for lead to be about 2 years in the upper 100 m of the open ocean, not less than 20 years in the thermocline, and some 80 years in deep waters. The distribution of lead in the ocean, reflecting as it does an unusual pattern of input, is unlike those known for other trace metals. It resembles manganese in some respects but, as discussed by Schaule and Patterson,26 there are significant disparities which probably reflect differences in sources. This matter is considered further in the subsequent discussion of manganese. Numerous calculations have been made of the equilibrium distribution of lead between the various complexes formed with inorganic ligands in sea water.* Dyrssen and W e d b ~ r gestimated ~~ the major species to be PbCl: (42%) and PbCI+ (19%) with PbC1; (9%), PbOHf (lo%), and PbOHClO (9%) as other significant complexes. The importance of complexing by chloride is again suggested by the calculations of Morgan and Sibley,28 and also those of Long and an gin^,^^ who estimate PbCIS to be the main complex, with significant amounts of PbCO:, PbCI:, and Pb2+. Other m o d e l ~ , ~however. ~ , ~ ' indicate that 65-68% of the element exists as PbCO!, one3l suggesting also PbCIi- as a major species (29%). The lack of agreement between equilibrium speciation models, not only for lead but for many other elements, arises mainly because of differences in the complexes selected for inclusion in the models, and different choices of stability constants for the complexes from the often disparate values given in the literature. For lead, a critical evaluation of the relevant data has been made by Whitfield and Turner.32 They arrive at the following speciation: PbCO! (55%), PbCI: ( 1 1%). Pb(C0,)Cl(lo%), and PbCI+ (7%): no other species comprises >5% of the total. Pb2+ accounting for only 2%. Mixed ligand complexes have frequently been neglected in speciation models but are significant for lead, particularly at higher pH. The importance of mixed ligand complexes for several elements was emphasized by Dyrssen and W e d b ~ r g . * ~ Arsenic.-Recent work on arsenic has often used methods capable of providing information on the chemical form of the element. Arsenite (As"') is thermodynamically unstable in sea water and from equilibrium considerations the element should be present as arsenate (As"). The rate of oxidation of arsenite, added to water from the Sargasso Sea, has been studied e ~ p e r i m e n t a l l yand ~ ~ was found to be significantly influenced by temperature, salinity, pH, and initial arsenite concentration. Direct sunlight increased the oxidation rate by a factor of 5-10. * Unless otherwise stated the results quoted for equilibrium models are for seawater at a pH close to 8. a temperature of 20-25 "C, under a total pressure of 1 atm.. and containing free dioxygen. *'D. Dyrssen and M. Wedborg, in 'The Sea. Volume 5: Marine Chemistry'. ed. E. D. Goldberg. Wiley-Tnterscience. New York. 1974, pp. 18 1-195. J. J . Morgan and T. H. Sibley. in 'Proceedings Civil Engineering in the Oceans/IlI'. American Society of Civil Engineers, New York, 1975. Vol. 2, pp. 1332-1352: T. H. Sibley and J . J. Morgan. in Proceedings of International Conference on Heavy Metals in the Environment. ed. T. C. Hutchinson, University of Toronto, 1975, Vol. 1, pp. 319-338. 2 9 D. T. Long and E. E. Angino, Geochim. Cosmochim. Aclu, 1971,41. 1183. 3" T. M. Florence and G. E. Batley, Talanfa,1976, 23, 179. 3 1 J. C . S. Lu and K. Y. Chen, Entiiron. Sci. Techno/., 1977. 11. 174. '*M. Whitfield and D. R. Turner in 'Lcad in the Marine Environment'. cd. M. Branica and Z. Konrad. Pergamon Press. Oxford. 1980. pp. 109-148. 1 3 D. L. Johnson and M. E. Q. Pilson. Emiron. Lcll.. 1975. 8. 157.

Constituents in Ocean Waters

241

With an arsenite concentration of 10 nmol 1-' the initial oxidation rate under characteristic conditions for oceanic deep water was estimated as 23 nmol I-' year-'. Slower initial rates would apply at the lower concentrations of As"' recently reported for deep waters. The occurrence of monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) in shore samples of sea water was reported by Braman and F ~ r e b a c k . ~ ~ Andreae35 carried out detailed studies of the occurrence of these forms, and of arsenite and arsenate, in samples from the Southern Californian Bight; mono-, di-, and tri-methyl arsines and trimethyl arsine oxide were sought but not detected. The organic forms (MMAA and DMAA) were generally confined to the euphotic zone; their distributions and correlations with chlorophyll concentrations and rates of carbon fixation, indicated their production either by phytoplankton or by associated heterotrophic micro-organisms. The distributions of the two organic forms in the euphotic zone were similar, concentrations decreasing markedly around the base of the euphotic zone. In the uppermost 20 m, DMAA concentrations ranged from 1.4-3.5 nmol I-' and those of MMAA from <0.03-0.4 nmol I-'. Apart from stations affected by eutrophication, where up to 84% of the total inorganic arsenic could be present as As"', concentrations of arsenite were usually from 0.1-0.4 nmol 1-', these amounting to up to 2.5% of the inorganic arsenic. In some profiles arsenite occurred quite uniformly in the euphotic zone, whereas in others it showed a marked increase near the base of the euphotic zone and extending below it. Total dissolved arsenic increased in concentration down the profile, most markedly over the depth range 1 0 0 - 4 0 0 m, to about 24 nmol I-], as compared with an average concentration of about 18 nmol I-' at the surface. In samples from below the euphotic zone, As"' amounted in some cases to <1% of the total arsenic. Results36 for marginal basins off southern California and in the northeastern Pacific Ocean extend these findings. Arsenic (v) increased with depth and for deep-water stations concentrations become fairly uniform below 1 km with an average value of 24 nmol I-' : As"' amounted to about 0.1 nmol 1-' at these depths. A fairly uniform distribution of total arsenic for five widely separated vertical profiles in the western basin of the Atlantic Ocean has been r e p ~ r t e d , ~the ' average concentration being 2 1 nmol I-'. Other reports on the oxidation state of arsenic include measurements on Sargasso Sea waters38 showing 0.9-5.3 (mean 3.2) nmol As"' 1-' in samples to 100 m, and 18-25 (mean 21) nmol As" 1-' in samples to 700 m, and the finding39 that 7-20% of the total arsenic existed as As"' in coastal surface waters containing found that 70% or more of the arsenic 19-33 nmol total As I-'. Carpenter et in typical Puget Sound sea waters, containing 20-23 nmol I-', was present as arsenate. For the shelf waters of the Georgia Bight (average concentration of arsenic of 15 nmol I-'), up to 20% of the total occurs as As"' and DMAA.4' R. S . Braman and C. C. Foreback, Science, 1973, 182. 1247. M . 0. Andreae, Deep-sea Res.. 1978, 25, 391. 36 M. 0. Andreae, Limnol. Oceanogr., 1979. 24,440. '' D. E. Robertson, Trans. A m . Nucl. SOC..1977, 27, 170. '*D. L. Johnson and R. S . Braman, Deep-sea Res., 1975. 22. 503. lY S. Gohda, Bull. Chem. SOC.Jpn., 1975, 48, 1213. 40 R. Carpenter, M. L. Peterson, and R. A. Jahnke in 'Estuarine Interactions', ed. M. L. Wiley, Academic Press. New York. 1978, pp. 4 5 9 4 8 0 . 4 1 D. G. Waslenchuk. Mar. Chern.. 1978. 7. 39. 34

35

242

Environmentai Chemistry

The occurrence of As"' and methylated arsenic compounds in surface waters reflects their formation by biological processes. Transport with biogenous particulates can account for the increase in concentration of arsenic in deeper waters. This increase is, however, much less marked than for the micronutrients and certain trace metals, such as barium, zinc, and cadmium, indicating a relatively minor role for the process. This is also shown by the small difference between the concentration of arsenic in deep waters of the Atlantic and Pacific Oceans. The existence of a detectable, albeit very low, concentration of As"' in deep is not expected on the basis of thermodynamic calculations and is presumed to reflect an environmental oxidation rate sufficiently low to allow the detectable amounts to persist in a steady-state condition, following formation and transport. This behaviour is in contrast to that of selenium which is discussed below. Apparent dissociation constants of arsenic acid have been determined4* in artificial sea water for various values of salinity and temperature. The results show that for typical sea water at 25 "C about 97% of As" exists as HAsOt-. Antimony.-A concentration of 3.6 nmol kg-' has been reported43for a composite of three samples of water from 3000 m in the Caribbean Sea. Bismuth.--Analysi~~~of a sample from 2550 m in the North Pacific Ocean gave a concentration of 0.2 nmol kg-'. As with antimony, the general features in the distribution of this element remain uninvestigated. Selenium.-As with arsenic, a main interest concerning selenium in seawater has been the oxidation state of the element. Thermodynamic equilibrium considerations indicate that the dissolved element should occur as selenate (SeV1)in the oceans, but substantial evidence has recently been obtained for the occurrence of significant amounts of selenite (Se'"). Surface waters of the western North Pacific were reported by Sugimura et al.44to contain 760-1520 pmol 1-' with 50-80% as SeIV.Three vertical profiles showed total selenium to be uniform in the mixed layer (890-1140 pmol I-'), with an increase in deeper water, samples below 1 km containing on average 1880 pmol l-I. Concentrations of Se" were also nearly constant in the mixed layer (630-760 pmol I-') and there was only a moderate increase with depth, to 760-1 140 pmol 1-I.

Whereas these profiles suggested that the main increase in concentration of total selenium with depth is due to an increased concentration of Sev', investigations in the eastern North Atlantic Ocean4' presented a different picture. For stations in the area 20-25ON, 18-3 1O W concentrations of SeIV were generally undetectable (below 25 pmol 1-I) at the surface and increased with depth reaching 380-505 pmol 1-' in deep water. Profiles in the western Atlantic Ocean around the latitude of the Strait of Gibraltar were similar, except that advected Mediterranean water led to distinctly lower concentrations of SeIV at intermediate depths. Concentrations of D. H. Lowenthal, M. E. Q. Pilson, and R. H. Byrne, J. Mar. Res., 1977, 3 5 , 6 5 3 . T. R. Gilbert and D. N. Hume, Anal. Chim. Acta, 1973, 65,45I. 44 Y. Sugimura, Y. Suzuki, and Y. Miyake, J . Oceanogr. SOC.Jpn., 1976. 3 5 235. 45 C. I. Measures and J. D. Burton, Earth Planet. Sci. Lett., 1980, 46, 385. 42

43

Constituents in Ocean Waters

243

total Se in the profiles increased from 320-950 pmol I-’ in the uppermost 100 m to 990-1750 pmol I-’ in waters below 1 km. Examples of the different situations reported for the two regions are shown in Figure 3. Regression analysis45 of the data for the Atlantic Ocean, suggests that SeIV may be more closely correlated with silicon than with phosphate, while the reverse is true for Sevl (calculated as the difference between total Se and Se”). Some of the transport of selenium to deeper waters in association with biogenous material, must Se/pmol I-’

Se/pmol I-’

0

500

1000

1500

2000 0

500

1000

1500

2000

0

1

E

< 5 Q

e,

n

3

4

Figure 3 Vertical distributions of selenium(1v) (closed circles) and total dissolved selenium (open circles) at two stations in the northeastern Atlantic Ocean: (a) 23”06’N, 27O52’W; (b) 36O01’N, 1Oo49’W. (Redrawn from figures in Earth Planet Sci. Lett., 1980, 46, 385; with permission of Elsevier Scientific Publishing Co.)

however occur in the form of Se-I1 sinCe the element is to some degree metabolized along reductive pathways analogous to those for sulphur. Very low concentrations (<25-80 pmol I-’) of lower oxidation states, i.e. Se-I*.O, have been reported for nearshore samples of sea water.46 The persistence of Se’” as a major form in deep waters, which contrasts markedly with the case of arsenic, discussed in an earlier section, may be due to its kinetic stability in the oxidative cycle of the element. A detailed study4’ of a vertical profile of a station in the northeastern Pacific Ocean shows a distribution with the same general characteristics outlined above for 46 47

H. Uchida, Y. Shimoishi, and K. T6ei. Environ. Sci. Technol., 1980, 14, 541. C . 1. Measures. R. E. McDuff, and J. M. Edmond, Earth Planer. Sci. Lerr., 1980, 49, 102.

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Environmental Chemistry

the Atlantic Ocean. Concentrations increased from surface to deep water from 50-800 pmol kg-' for SeIVand 500-1 500 pmol kg-' for Sev'. Several stations in the Indian Ocean48 also showed low surface values of SeIVof 70-125 pmol I-', increasing to 710-870 pmol I-' in bottom water; values for SeV1ranged from 330-390 pmol I-' at the surface to 1140-1420 pmol 1-' near the bottom. At one station with a broad dioxygen-minimum zone there was evidence of the loss of some selenate from the water column. There thus appears to be an approximate doubling in the concentration of SeIVin deep water of the North Pacific Ocean as compared with the North Atlantic Ocean, comparable with the increase in phosphate, although the corresponding increase in total selenium is only about 45%. This suggests the importance of the downward transference of selenium in oxidation states lower than (vI). Concentrations of Sex" of <65 pmol I-' have been reported49 for Californian nearshore waters that contained 740-1015 pmol I-'; in the Santa Catalina Basin, concentrations of Se'" increased from <65 pmol 1-' at the surface to 890 pmol I-' at ~ ~ reported , ~ ~ significant but very variable the bottom (13 10 m). Other ~ o r k e r shave proportions of SeIVin coastal waters. Iodine.-The chemistry of iodine in sea water is complex, since although the only clearly identified species are in oxidation states (-I) (iodide) and (v) (iodate), additional oxidation states of (0) (molecular iodine) and (I) (hypoiodite) are involved as intermediates in the marine cycle of the element. At thermodynamic equilibrium at a p E of 12.5, iodate is the only stable dissolved form of iodine in sea water, but iodide forms a significant proportion of the total iodine in some circumstances. The distribution of iodide suggests that its presence reflects inputs or in situ production of the reduced form. WongS1 presented an oxidation-state diagram for the aqueous iodine system, which shows that iodide should be the most stable species in anoxic waters under both acidic and basic conditions and, which demonstrates the stability of iodate in normally oxygenated sea water (see Figure 4). It has been shown e ~ p e r i m e n t a l l y ~ 'that * ~ * molecular iodine is unstable in sea water. The rate of reduction found by T r ~ e s d a l eexceeded ~~ that of disproportionation to iodide and iodate; there appeared to be two reduction processes with different rate constants and the results suggested that part of the dissolved organic matter has a reducing capacity that was saturated at the concentrations studied. The amount of analytically reactive iodine in coastal and shelf sea waters is increased by about 1-1 3% when organic matter is photo-oxidized,s3 suggesting the presence of an organically bound fraction of the element. Wong5' concluded from experimental studies that the reaction of molecular iodine in sea water probably involved dominantly hydrolysis to hypoiodite (which may react with organic matter, with iodide and iodinated organic compounds as possible products), or 4 R C .1. Measures. R . J. Mangum, and J. M. Edmond. Trans. Am. Geophys. Union. 1980. 61. 987 (Abstract). 4y G. A. Cutter, Anal. Chim. A d a , 1978, 98, 59. Y . Shimoishi. Anal. Chim. Acfa, 1973. 64. 465: Y. Shimoishi and K. T6ei. ihid.. 1978. 100, 65. 5 ' G. T. F. Wong, Mar. Chem.. 1980. 9. 13. 5 2 V. W. Truesdale. Deep Sen Rey.. 1974. 21. 761. 53 V. W. Truesdale. Mar. Chern., 1975. 3. 1 1 1.

Constituents in Ocean Waters

245

autodecompose to iodide. The mechanism for the oxidation of iodide to the thermodynamically stable iodate remains unclear. Wong and Brewers4 measured iodate in three profiles in the South Atlantic Ocean. In the Argentine Basin, iodate concentrations increased from about 4 0 0 nmol 1-l at the surface to 475-510 nmol 1-' below 4 km. The changes with depth 10

-

I

8 '

1

6 .

0

+

h

-

I

0

c

a,

m .-

0

4 '

3

u + -

.c. -

0

>

0

> 2

' -1

0 I

d

Oxidation S t a t e

-2 Figure 4 Oxidation-state diagram of the aqueous iodine system. The diagram shows the llolt equivalent f o r each oxidation state for: anoxic conditions at pH 0 (closed circles); anoxic conditions at p H 14 (open circles): normal oxygenated sea water conditions. pH 8, 0.21 atm. of oxygen (crosses). The volt equivalent is the product of the oxidation-state number and its redox potential (European comention) relative to the element in its standard state: mimimum i7alues indicate the most srahle oxidation state. (Redrawn from a figure in Mar. Chem., 1980. 9, 13: with permission of Elsevier Scientific Publishing Co.)

correlated closely with nitrate, phosphate, and, to a lesser extent, with the apparent dioxygen utilization, and suggest an appreciable flux of iodine associated with the biogenous particulate material. In the Angola Basin, the surface concentration was lower (275 nmol 1 - l ) and the correlation with the micronutrients was weaker. The j4

G. T. F. Wonp and P. G. Brewer, J . Mnr. Res.. 1914. 32. 25.

246

Environmental Chemistry

distribution of iodate in the Venezuela Basin55 (Figure 5a) accords with the findings for the Argentine Basin. A maximum is apparent coinciding with that for phosphate and with the dioxygen minimum; iodide was only detectable in the upper 200 m. Extensive r n e a s ~ r e m e n t sin~ ~the equatorial Atlantic Ocean showed a marked depletion of iodate in the upper 30-40 m, with concentrations below 300 nmol 1-’. A continuous lens (10-20 m thick) of water with maximum iodate concentrations in the range 450-600 nmol I-’ was observed, coinciding with the core of high salinity water associated with the Equatorial Undercurrent; this high iodate is probably an advective feature. A profile of iodide showed significant concentrations in near surface waters, amounting to about 25% of the total iodine; below 200 m the iodide concentration was only a few per cent of the total. Results for several stations in the North Atlantic Ocean and the tropical Western Indian Ocean are given by T r ~ e s d a l e , ~who ’ stresses the lack of evidence from his own findings and those of other workers for significant variations in the concentrations of iodate with depth below the uppermost 200 m. He also found no systematic seasonal variations in the concentrations of iodate and total iodine over an annual cycle in coastal temperate waters. Data55 for two anoxic basins, the Cariaco Trench and the Black Sea, show a pronounced contrast in behaviour associated with the drastic reduction in p E in deeper waters where sulphide is present. This is shown by the results for the Cariaco Trench in Figure 5b. For the Black Sea there was evidence for a significant input of iodide from bottom sediments. A similar alteration in speciation associated with changes in the redox conditions in the water column has been found in Saanich Inlet;58 it was again shown that iodide formed a significant fraction of the total iodine in the surface waters despite its thermodynamic instability under these conditions. Zinc.-Problems of contamination, during sampling and analysis, have been acute for zinc. Determinations of the element taking the fullest precautions to overcome this problem have been made in the North Pacific Ocean by Bruland and his c o - w o r k e r ~ The . ~ ~results ~ ~ ~ for a series of samples taken between California and Hawaii show variations in surface waters from 0.34 nmol kg-l at a coastal station where upwelling occurred, t o a mean value of 0.07 nmol kg-I in the oligotrophic central oceanic gyre region; at one station the surface concentration was as low as 0.01 nmol kg-’. Even the higher surface concentrations found by Bruland and his co-workers are several orders of magnitude below others reported recently, values and in those studies where vertical distributions were examined showed unsystematic variations with depth in contrast with the four profiles examined in the North Pacific Ocean. These show an increase to concentrations of about 9 nmol kg-I in deep water and a very close linear correlation ( r = +0.996) 16v61-63

16762*63

G. T. F. Wong and P. G. Brewer. Geochim. Cosmochim. Acta, 1977. 41, 151. G. T. F. Wong, Deep-sea Res.. 1977,24, I 15. 5 7 V. W. Truesdale. Mar. Chem., 1978, 6, 1. 5 H S. Emerson, R. E. Cranston, and P. S. Liss, Deep-sea Res., 1979, 26, 859. J y K. W. Bruland, G. A. Knauer, and J . H. Martin. Nature (London). 1978, 271, 741. 60 K. W. Bruland, Earrh Planet. Sci.Lett., 1980, 47, 176. 6 1 R. Chester and L. H. Stoner, Mar. Chern., 1974, 2, 17. K. Kremling and H. Petersen. “Meteor”ForschunRserReb., Reihe A . 1977, No. 19, 10. 6 3 L.-G. Danielsson. Mar. Chem., 1980, 8, 199. ST

56

4.0

3.0

2.0

r

0.1

0.2

0.3

0.4

r

0.5

E

5n

\ Y

1.4

1.2

1.o

0.8

0.6

0.4

0.2

0

0 0.1

0.2

0

0.3

I/pmol I-'

I

I

0.4

0

0

0

0

.

0

0.5

0.6

;igure 5 Vertical distributions of iodine (closed circles) and iodate (open circles) at two stations in the western Atlantic Ocean: (a) the Venezuela Basin (13O22'N, 64O43'W); (b) the Cariaco Trench ( 10°32'N, 64O45'W). Hatched lines indicate depth at sea bed. (Redrawn from figures in Geochim. Cosmochim. Acta, 1977, 41, 15 1; with permission of Pergamon Press Ltd.)

n

P)

E e 5 Q

1 .o

0.2 0.2

0

I/pmol I-'

-I

P

h)

cl

248

Environmental Chemistry

with those of silicon. This suggests that the transport of zinc involves primarily a phase, probably skeletal material, with a deep regeneration cycle. Results from one of these profiles are shown in Figure 6. Zn/nmol I-' 0

3

6

0

40

80

9

12

0

1 E . . Y

5 Q

n 2

3 120

160

Si/pmol I-'

Figure 6 Vertical distribution of zinc (closed circles) and silicon (open circles) in the eastern

North Pac8c Ocean (37'05'N, 123'22'W). (Redrawn from a figure in Nature (London), 1978. 271, 741: with permission of Macmillan Journals Ltd.)

The inorganic speciation of zinc in seawater has been calculated by several workers using ion-association equilibrium models, as summarized in Table 1. Morgan and SibleyZscalculated that chloro complexes formed the major fraction of zinc species, with the free ion of next greatest significance. Long and Angino2Y estimated Zn(0H); to be the dominant species with the free ion of next importance: Table 1 Percentage distribution of zinc between its principal inorganic species irr sea water Zn2+

16 55

47 6 38 O4

ZnOH+

Zn(0H);

ZnCI+

2 2
-

44 31 20

<1 72 30

10

18

ZnCIy Zn(0H)CI" ZnCO!

ZnSOt

Ref.

15

13

-

-

2 6 10 2

27 21 64 30 31

10 5 7

3 6 -4

2 -

4

R . F. C. Mantoura. A . Dickson. and J . P. Riley. Estuarine Coastal Mar. Sci.. 1978. 6. 387.

Constituents in Ocean Waters

249

the dominance of Zn(0H): increased markedly with increase of pH. The main reasons for major disagreements between equilibrium models have already been indicated. Cadmium.-The first detailed observations of concentrations of cadmium in ocean waters, showing distributions that resemble those of the principal micronutrient . former ~ ~ workers elements, were reported by Boyle et a1.'j5 and Martin et ~ 1 The investigated three profiles in the Pacific Ocean representing widely differing oceanographic conditions. In the upwelling region of the Bering Sea the surface concentrations were 0.6 1 nmol kg-I, whereas lower concentrations of about 0. I 2 nmol kg-I were found at the stations in the temperate mid-Pacific and south of New Zealand. The concentrations increased sharply with depth to a maximum somewhat over 1 nmol kg-I. The distribution was closer to that of phosphate than of silicon suggesting regeneration in a shallower cycle than has been indicated for zinc. In a study66 of the California Current region, near-surface concentrations for offshore stations were found to average 0.05 -t 0.01 nmol I-'. An increase in concentration occurred in the pycnocline with up to 0.6 nmol I-' being found at 8 0 m; the increase paralleled those of phosphate and nitrate. Samples collected by screen from the ocean-atmosphere interface showed a definite enrichment in cadmium, concentrations ranging from 0.13-0.5 nmol I-'. Nearshore stations in the South California Bight region showed significant increases in concentration throughout the water column. Further data have been reported for surface and deep waters off California6' and on a section between California and Hawaii.60 In the latter work an extremely low concentration of 0.002 nmol kg-' was determined for the central oceanic gyre region. Close correlations of the concentrations were found again with phosphate and also with nitrate. The relationship with phosphate given by Bruland60 is Cd(nmol kg-')

= (0.347

-t 0.007) PO,(pmol kg-I)

-

(0.068 k 0.01 7)

with a correlation coefficient, r, of 0.992. From these studies it was suggested that a close relationship between cadmium and phosphate applies generally to the ocean except in areas directly influenced by localized inputs. Brewer and Hao68 have pointed out that the close correlation with phosphate indicates that the deep-water scavenging of cadmium must be small. By the application of advection-diffusion modelling to data for one of the Pacific stations they estimate the lower limit for the scavenging residence time of cadmium to be about 1.8 x lo5 yr. Data for the Indian Ocean63also show an increase in concentration of cadmium with depth and a correlation with the concentrations of phosphate and nitrate. Significant correlations were only obtained, however, when the data were grouped in two sets according to region. The slopes of the regression relationships differed E. A. Boyle, F. Sclater, and J. M. Edmond, Nature (London), 1976, 263, 42. J. H . Martin, K. W. Bruland, and W. W. Broenkow, in 'Marine Pollutant Transfer', ed. H. L. Windom and R. A. Duce. Lexington Books, Lexington, 1976. pp. 159-184. '' K . W. Bruland, G. A . Knauer, and J . H. Martin, Limnol. Oceanogr., 1978, 23.618. 68 P. G. Brewer and W. M. Hao. in 'Chemical Modeling in Aqueous Systems', ed. E. A. Jenne. American Chemical Society. Washington. DC, 1979. pp. 261-274. h6

250

Environmental Chemistry

appreciably, although the intercepts were similar. For five stations concentrations in near-surface and deep water were 0.13 k 0.04 and 0.57 k 0.16 nmol I - I , respectively. The distribution of cadmium in the Atlantic Ocean requires fuller investigation. For the Sargasso Sea, Bender and Gagnefj9 concluded that the probable concentration in surface water was less than 0.05 nmol I-’ and that in deep waters (1.8-4 km) it was about 0.22 nmol I-’. An average concentration of 0.4 nmol I-’ has been r e p ~ r t e d ’for ~ Central Atlantic water upwelling off Nova Scotia. Other measurements on samples from vertical ~ e c t i o n s ’ ~ *and ~ ~ *on’ ~various surface waters6’ have given generally higher concentrations, and profiles which could not be related to the distribution of the micronutrient elements. S t ~ d i e s ~ ~ofi ~the~ -speciation ~ ~ - ~ ~of cadmium based on equilibrium ionassociation models are in agreement in showing the dominance of chloro complexes with only a small fraction (< 1-3%) present as the unassociated cation. There has been less agreement as to the relative importance of the various chloro species, Reported numerical data are summarized in Table 2. Long and an gin^^^ and Mantoura et al.64show CdCI: and CdCI+ as the dominant species.

Table 2 Distribution of cadmium between its chloro species in sea water* CdCl+ 29 34 28 57

CdCI! 38 51 30

CdCl; 28 12 26 9

15 * Values are percentages of total cadmium

CdClz-

R eJ

-

-

9 10

-

27 21 30 31

CdC1:-

-

9

Mercury.-As a result of concern about pollution with mercury in certain very restricted marginal regions and the high concentrations, now recognized to be natural, in top-predator fishes, tuna and swordfish, from the open ocean, considerable effort was devoted up to the mid 1970s to establishing the base-line concentrations of this element in oceanic waters. Even with the more recent of these s t ~ d i e s , ~ ~many * ~ ~ -of’ ~the data fail to fit any coherent picture consistent either M. L. Bender and C. Gagner, J. Mar. Res., 1976, 34, 327. J. M. Bewers, B. Sundby, and P. A. Yeats, Geochim. Cosmochim. Acta, 1976,40,687. 71 A. Eaton, Mar. Chem., 1976, 4, 141. 72 P. M. Williams and H. V. Weiss, J. Fish., Res. Board Can., 1973, 30, 293; R. Chester, D. Gardner, J. P.Riley, and J. Stoner, Mar. Pollut. Bull., 1973, 4, 28; T. M. Leatherland, J. D. Burton. F. Culkin. M. J. McCartney, and R. J. Morris, Deep-sea Res., 1973, 20, 679; R. A. Fitzgerald, D. C. Gordon, jun., and R. E. Cranston, ibid., 1974,21, 139; D. Gardner and J. P. Riley, J. Cons., Cons.Int. Explor, Mer. 1974, 35, 202: J. 6lafsson, Anal. Chim Acta, 1974, 68, 207; P. M. Williams, K. J. Robertson, K. Chew, and H. V. Weiss,Mar. Chem., 1974, 2,287. ” W . F. Fitzgerald and C . D. Hunt, J . Rech. Atmos., 1Y74, 8, 629; W. E. Fitzgerald, in ‘Analytical Methods in Oceanography’, ed. T. R. P. Gibb, American Chemical Society, Washington, DC 1975, pp. 99-109. 74 R. A. Carr, M. M. Jones, and E. R. Russ, Nature (London). 1974, 251,489; R. A. Carr,M. M. Jones, T. B. Warner, C. H. Cheek, and E. R. Russ, ibid., 1975, 258,588. 7s K. Matsunaga, M. Nishimura, and S . Konishi, Nature (London), 1975, 258, 224. 76 J. 6lafsson, Nature (London), 1975, 255, 138. 77 H. L. Windom, F. E. Taylor, and E. M. Waiters, Deep-sea Res., 1975,22,629. H. L. Windom and F. E. Taylor, Deep-sea Res., 1979,26, 283. 7 9 J. D. Burton, G. B. Jones, and H. S. Matharu, in Deep-sea Research Supplement ‘A Voyage of Discovery’, ed. M. Angel, Pergamon Press, Oxford, 1977, pp. 147-156.

69

70

Constituents in Ocean Waters

25 1

between investigations or with the distributions of other oceanographic variables. I n view of the apparent analytical 'noisiness' of many data an extended discussion of the findings is unwarranted. Recent measurementsso on a profile in the Gulf Stream at 39O 10" 65O3OfW, show systematic variations with depth. Concentrations were at the extreme low end of the range reported for sea water, the values for reactive mercury (that fraction reduced to the element by stannous chloride under acidic conditions) averaging 20 pmol I-' with a standard deviation of 5 pmol I-'. The concentrations of mercury were significantly correlated with those of dissolved silicon. Similarly low concentrations have been for the Kuroshio and Oyashio regions and the Japan Sea with values of 25 It 2.5 pmol I-' for waters down to about 1200 m, but systematic variations as found in the Gulf Stream were not demonstrated. A mean pmol I-') was found73 for total concentration of 40 pmol I-' (range 25-60 northwest Atlantic Ocean waters and similarly low values for some oceanic waters were given in several of the other reports. The view that the typical concentration of mercury in open ocean waters is substantially below 50 pmol I-' is supported also by findingss' of total mercury concentrations averaging 40 pmol I-' in surface waters around the United Kingdom, excluding certain high values associated with pollution sources or unusually high amounts of suspended matter. In coastal regions a considerable proportion of the mercury present can be associated with particulates. In this work it was shown that only some 25-50% of the mercury found in samples subjected to oxidation was analytically available if this treatment were omitted. Matsunaga et aZ.75also consider that there was an analytically unavailable fraction, amounting to at least some 30%, in their samples of oceanic waters. Use of photo-oxidation for the decomposition of organic material in sea water has, however, not shown the although such a existence of a significant unreactive fraction in open ocean fraction has been found in some coastal water^.^^^^^ Although recent studies suggest a low characteristic concentration for mercury in oceanic waters, there is substantial evidence for much higher concentrations in waters affected by local inputs. Perhaps the most clearly defined influence is that of submarine geothermal activity. Thus, high concentrations have been observed intermittently in near-bottom waters of the FAMOUS area of the mid-Atlantic Ridge.74 On different sampling occasions, individual samples showed a range of 60-7 100 pmol l-l, median concentrations varying between 330-5400 pmol I-*. Waters near Iceland influenced by the Heimaey eruption contained76up to 2400 pmol I-'. A further influence on the concentration of mercury in surface ocean waters may be the atmospheric input from terrestrial sources. Windom et al.77 found that in surface waters of the southwestern North Atlantic continental shelf there was a marked seasonal variation in concentration related to meteorological conditions. Concentrations were higher following periods of predominantly westerly winds than following periods dominated by easterly winds. Subsequent work 7s indicates that P. Mukherji and D. R. Kester, Science, 1979, 204, 64. C. W. Baker, Nature (London), 1977, 270, 230. ** W. F. Fitzgerald and W. B. Lyons, Nature (London), 1973, 242,452; W. F. Fitzgerald, W. B. Lyons, and C. D. Hunt, Anal. Chern., 1974,46, 1881.

25 2

Environmental Chemistry

atmospheric inputs of mercury to the shelf waters of the South Atlantic Bight are about an order of magnitude greater than the river inputs: the dominant control on the concentrations in these waters, however, is the inflow of Gulf Stream waters. The use of equilibrium association modelling to calculate the speciation of mercury in sea water shows that chloro complexes are dominant. The concentration of the uncomplexed mercuric cation has been estimated2*to be about fourteen orders of magnitude lower than those of the chloro complexes. According to Dyrssen and Wedborg2' and Ahrland,21HgCIi- accounts for 66% of the total, with significant fractions existing as HgC1; (12%) and HgCI3Br2- (12%). The . ~ similar ~ importance for HgC12,- and HgCIy, but model of Mantoura et ~ 1 indicates suggests that HgCI! and HgC1,Br2- each account for about 5% of the total. Lu and Chen3' also calculate HgCl2,- (80%) and HgCI, (15%) to be the principal species in oxidizing conditions, and show HgSi- as the only significant species in anoxic waters. Vanadium.-Determinations of vanadium have been madeE3on a section in the northeastern Atlantic Ocean, with samples from the surface to 1 km. Concentrations ranged from 16-3 1 nmol I-' with a mean of 23 nmol I-'. Most of the variation was probably accounted for by the analytical precision. This study suggests rather similar behaviour for vanadium and molybdenum (see below) although the concentrations of the two elements do not appear to be correlated, presumably because analytical variability is a major factor and the concentration ranges are rather narrow. Ahrland2' concluded from thermodynamic calculations that the main species of vanadium present in sea water are probably the mononuclear ions H2V0, and HVOZ-, with the latter slightly predominant. Chromium.-From thermodynamic considerations,21 chromium would be expected to occur in sea water essentially entirely in the (VI) oxidation state, as the chromate ion, CrO:-. There is, however, as with other redox couples discussed previously, a significant role of the reduced state, C P , in natural waters, as shown by environmental measurements. This is despite the fact that laboratory experimentsg4 suggest that CrIrlis rapidly oxidized to CrV1in sea water. In a detailed profile in the northeastern Pacific Ocean,85 concentrations of chromium increased with depth from about 1.7 nmol I-' at the surface to about 3 nmol I-' at 3 km depth. Chromium(m) was a significant fraction only in the euphotic zone where it showed a peak at 75 m, coinciding with the primary nitrite maximum. Average concentrations of CrV1for the region were 2.0 & 0.4 nmol I-' above 100 m and 2.8 k 0.7 nmol I-' below 100 m, with corresponding values for Cr"' of 0.15 f 0.13 and 0.04 k 0.04 nmol 1-'. The changes in concentration of Crvl with depth were closely correlated with those of silicon. Higher concentrations of chromium of about 4 nmol I-' were reported by Shigematsu et aLS4for two samples from the upper 100 m at a station in the northwestern Pacific Ocean, with Cr"' A. W. Morris, Deep-sea Res., 1975. 22, 49. T. Shigematsu. S. Gohda, H. Yarnazaki, and Y. Nishikawa. Bull. Insr. Chem. Res., Kyoto Uniii., 1977, 55, 429. R5 R. E. Cranston and J. W . Murray, Anal. Chim. Acta, 1978,99, 275.

13'

u4

Constituents in Ocean Waters

253

accounting for 5--14%; these workers give the fraction of Cr"' in coastal waters, containing higher concentrations of chromium. as ranging from 3-57%. Concentrations of chromium for two stations in the northwestern Atlantic Ocean were found by Campbell and Yeahs6 to be about 3.5 nmol 1-I in surface waters, increasing with depth to some 5 nmol I-' at about 3 km, with possibly a slight decrease in concentration below that depth. There were significant correlations of the concentrations of chromium with those of phosphate and silicon, the latter being more significant. A profile was examined in Baffin Bay, in which a surface layer of reduced salinity overlaid Arctic and Labrador Sea water masses. The concentrations of chromium increased from 3.2-3.9 nmol 1-' in the upper layers to an average value of 4.6 nmol I-' for samples from 30-2300 m. In the Labrador Sea the concentrations were fairly uniform with depth, ranging from 4.1-5.0 nmol I-' in the upper 1 km, despite considerable increases in the concentrations of phosphate and silicon over this depth range. The values for the Atlantic Ocean are higher than reported for the northeastern Pacific Ocean, but Campbell and Yeats refer to unpublished data of Cranston for the Pacific Ocean which extend over a similar range. The investigations discussed above have all given lower concentrations for total dissolved chromium in oceanic waters than were reported by Grimaud and M i ~ h a r for d ~ the ~ equatorial Pacific Ocean. These workers give values of 6.7-10.6 nmol I-' and claim that most of the chromium was present as Cr"'. The majority of the recent data for chromium suggest a distribution with a general tendency for increases in concentration with depth, related to the transport and dissolution of biogenous particulate material, but with a relatively small enrichment in the deep water as compared with such elements as zinc and cadmium. There is also a clear indication from the work of Cranston and Murrays5 that changes in the oxidation state may play a significant role in the behaviour of the element in the open oceanic water column. A marked change in oxidation state occurs between the oxic and anoxic layers of Saanich Inlet.58.85Chromium(v1) accounts for almost all the dissolved chromium in the upper oxic layer. Chromium(II1) becomes a more significant fraction near the interface between the oxygenated and sulphide-containing layers and becomes the dominant oxidation state in the anoxic zone. A decrease in the concentration of total dissolved chromium and an increase in that of particulate chromium occurs in the anoxic layers; this is in accordance with the fact that Cr"' occurs in a cationic form which is more readily taken up by particles than is the readily soluble chromate ion. The dominant species of Cr"' in both oxygen-containing and anoxic 31 waters are hydroxyl complexes.28* Manganese.-Several recent investigations of manganese in ocean waters have given results providing a consistent picture of the behaviour of the element. In a unfiltered samples were acidified to pH 2 before analysis so study by Bender et that the fraction of the element determined included dissolved forms leached from particulates under these conditions; it was suggested, however, that there was only a J . A. Campbell and P. A . Yeats, Earth Planel. Sci. Lett., 1981. 53,427. D. Grimaud and G. Michard, Mar. Chem.. 1974.2, 229. R R M . L. Bender, G. P. Klinkhammer, and D. W. Spencer, Deep-sea Res.. 1977, 24, 799. n7

254

Environmental Chemistry

minor contribution to this total dissolvable manganese (TDM) from particulate material that would be retained by a 0.6 pm filter. Measurements in the Sargasso Sea gave concentrations of about 2 nmol kg-I in near surface waters, 0.55 k 0.2 nmol kg-I between 1 . 8 4 km, and about 3 nmol kg-I in deep water. In the North Atlantic Ocean, values were more scattered but were around 2 nmol kg-I from 600-3100 m, with increases to >3.5 nmol kg-' in near-bottom waters. In the East Pacific Ocean at 33ON, surface waters contained 1.5 nmol kg-' and deeper waters 0.55 nmol kg-', but there was an increase to about 1.5 nmol kg-' in the dioxygen minimum region, which here contained only some 10 p m o l 0 , kg-I. Some earlier measurements of dissolved manganese in the Atlantic Ocean had indicated comparable concentrations to those found for TDM by Bender et a1.88 Thus concentrations of 0.5-1.6 nmol I-' were found in surface waters collected off the shelf west of Scotland.89A geometric mean concentration of 1.5 nmol I-' has been given70 for Atlantic Slope water off Nova Scotia; concentrations in Central Atlantic water in the same region were below 0.75 nmol I-'. Klinkhammer and Benderg0 reported vertical distributions of TDM for 13 stations in the Pacific Ocean. Concentrations of particulate manganese ranged from 5-50% of those of TDM and the trends in the two quantities were not generally related except in some bottom waters. Profiles in the Northern Hemisphere typically showed surface maxima of 1-3 nmol kg-I, concentrations decreasing below the mixed layer to about 1 nmol kg-I. In the dioxygen minimum zone increases in concentration of TDM, up to 3.9 nmol kg-I at one station, were often found, and below this zone, concentrations decreased to about 0.5 nmol kg-'. At some stations, increases in concentration occurred near the sea-bed. Profiles in the South Pacific Ocean mostly showed surface maxima but with concentrations (<1.5 nmol kg-I) lower than typical of the North Pacific Ocean; deep water concentrations were usually around 0.5 nmol kg-'. Concentrations of dissolved manganese in the surface mixed layer of the North Pacific have been shown9' to decrease from 1.0 to 0.6 nmol kg-' in going from the central oceanic gyre to the western boundary of the California Current and then to increase to 2-6 nmol kg-I near the coastal boundary. Maximum values (10-1 2 nmol kg-I) were found at 15-35 m on the eastern boundary of the California Current. In surface waters particulate manganese was only about 1% of the total; the proportion was higher in deeper waters but the particulates appear to contribute significantly to TDM only in near-bottom waters. The vertical distributions confirmed the earlier findings that maxima usually occur at the surface and can arise at the depth of the dioxygen minimum zone; results for one station are shown in Figure 7. Deep water concentrations were about 0.2 nmol kg-I. Similar surface concentrations of dissolved manganese of 3-9 nmol 1-I were reported9* for deep water stations close to the central Californian coast. Concentrations were m and similar in deep water. characteristically 0.9 nmol I-' between 150-300 Small maxima (ca. 1.5 nmol 1-') were associated with the dioxygen minimum zone. In summary, the above studies show a pronounced enhancement of con89

A. Preston, D. F. Jefferies, J . W. R. Dutton, B. R. Harvey, and A. K. Steele, Enuiron. Polluf., 1972,

3, 69. G. P. Klinkhammer and M . L. Bender, Earth Planet. Sci.Lett., 1980, 46, 36 1. 9 ' W. M. Landing and K . W. Bruland, Earth Planet. Sci.Lett., 1980, 49,45. 92 J. H. Martin and G. A. Knauer. E u r f h Planef. Sci. L e f f . ,1980, 51, 266. 90

Constituents in Ocean Waters

255

centration of manganese in surface waters, suggesting the effects of an external input and the scavenging of the element from deeper waters. The input of manganese to the surface mixed layer may reflect an atmospheric source. Klinkhammer and Bender9’ considered that this was supported by the similarity in the distributions of manganese and 210Pbin surface waters, the latter being known to have a dominantly atmospheric origin. Landing and B r ~ l a n d , however, ~’ showed that surface manganese concentrations increase markedly close to the continental boundary, whereas in this region concentrations of *loPb decrease, possibly as a Mn/n rnol kg-’

0

1

2

3

4

5

2

E \ Y

5Q n

Figure 7 Vertical distributions of dissolved manganese (closed circles) and total dissolvable

manganese (open circles) in the eastern North Pacijic Ocean (37O05’N, 1 2 4 O 12’W). (Redrawn from a figure in Earth Planet, Sci. Lett., 1980, 49, 45; with permission of Elsevier Scientific Publishing Co.)

consequence of increased scavenging by biogenous particulates associated with higher primary productivity. It is possible that because of the differences in the oxidation-reduction behaviour of the elements, the cycles of manganese and zlOPb are not coupled. Another possible input of manganese to surface waters is by advection from coastal waters where manganese is introduced from rivers and by remobilization from sediments under reducing conditions. Schaule and Pattersonz6 have pointed out that manganese (together with copper and nickel) shows an opposite trend to that of lead in its decrease in concentration in surface waters from the Californian coast towards the central ocean region: a comparison of the

256

Environmental Chemistr-v

near-shelf and oceanic vertical profiles for manganese and lead was also consistent with a difference in the dominant source of the elements, suggesting that the supply of manganese is not mainly aeolian. Where clearly defined subsurface maxima in the concentration of manganese have been observed they occurred either in the dioxygen minimum zone or in near-bottom waters. Maxima in the dioxygen minimum zone are almost always associated with concentrations of dissolved dioxygen below 100 pmol kg-' and, although possible influences of advection cannot be discounted, it seems probable that these maxima reflect in situ processes. Klinkhammer and Bendergo present detailed calculations which suggest that the in situ oxidation of organic matter with release of its manganese content may not be adequate to supply the observed concentrations. They consider the possibility that the concentrations are controlled by equilibrium with a solid phase and its variation in response to changes in the oxidation-reduction potential. The observed concentrations appear to fit more closely the equilibrium with hausmannite (Mn,O,) than with other manganese oxides which were considered. Under the fully anoxic conditions established intermittently in the bottom waters of Saanich Inlet very high concentrations of manganese, up to ca. 6 pmol 1-I occur.58 Concentrations of the order of 1 pmol 1-' exist in water containing low concentrations of oxygen just above the interface with sulphide-containing waters, reflecting the slow rate of oxidation of Mn". A marked increase in the concentration of dissolved manganese occurs also in the anoxic layers of the Cariaco Trench.93 The anoxic waters contain about 350 nmol kg-', with slightly higher values in the upper part of the anoxic zone: these values are about an order of magnitude higher than in the surface oxygenated waters. A pronounced maximum in particulate manganese occurs around the interface between the oxygenated and sulphidecontaining waters. In this zone manganese diffusing upwards becomes oxidized and precipitates: the settling particles re-enter the anoxic layer where they dissolve. Maxima in waters close t o the sea-bed in the open ocean may arise from inputs due to the hydrothermal interactions between sea water, and new basaltic crustal material, and by mobilization from sediments through interstitial waters. The latter process may involve transfer by diffusion across the sediment-water interface or may occur in association with resuspension of settled ~ e d i m e n t . ~Hydrothermal ' inputs are limited to regions of active sea-floor spreading. Klinkhammer er U I . ~ ~ found that in the Galapagos Rift region concentrations of T D M increase with depth from 0.8 nmol kg-' to 16 nmol kg-I, with the maximum values occurring at the depth of the ridge crest. Data for the water column overlying the Galapagos Rift have been fittedg5to a one-dimensional first-order scavenging model; the scavenging rate constant corresponds to a residence time for manganese in this water column of 51 years. Use of a one-dimensional horizontal model suggests that inputs may be propagated horizontally for a distance of the order of 1000 km. An increase in concentrations of particulate manganese, t o some fifty times the normal values, has been observedg6 in the bottom 600 m of water in the region of the Galapagos 9'

M. P. Bacon. P. G. Brewer. D. W. Spencer. J. W. Murray. and J. Goddard, Deep-sea Res., 1980,27.

119. G. Klinkhammer, M. Bender, and R. F. Weiss, Nature (London), 1977, 269. 319. 95 R. F. Weiss, Earth Plane!. Sci.Lett., 1977, 37. 257. 9 b G . W. Bolger, P. R . Betzer. and V. V. Gordeev, Deep-Sea Res.. 1978. 25. 72 1. 94

Constituents in Ocean Waters

257

Spreading Centre. The results of leaching experiments on the particulate material were consistent with the occurrence of the excess manganese in the form of amorphous hydroxyoxides. In oxygenated sea water, the only significant species of manganese would be M n 0 2 if equilibrium were attained.21 The observed concentrations of dissolved manganese are explicable in terms of the slow rate of oxidation of Mn". The metastable character of Mn" in sea water is clearly shown by the oxidation diagram for the element.97The equilibrium ion association models of Morgan and Sibley28 and Lu and Chen31 show chloro complexes as the dominant species of MnIXwith a significant amount of the unassociated cation, but Mantoura et aZ.64estimate the latter to be the major species. According to Lu and Chen3' the speciation is closely similar in dioxygen- and sulphide-containing waters. Iron.-The recent major advances in knowledge of the concentration ana behaviour of many trace metals have not extended to iron despite the geochemical importance of this element. D a n i e l ~ s o nhas ~ ~ emphasized two main problems in this regard. First, there is the possibility, as with other ubiquitous trace elements, that measurements have been affected by contamination during sampling and analysis, since the degree of precaution used, for example, in most recent studies of zinc and lead has not yet been applied in investigations of iron. Secondly, the chemical speciation of iron is unusually complicated because of its tendency to form a colloid of hydrous oxide. Different analytical methods may perhaps measure different fractions of the element in samples, which are either unfiltered or filtered through membranes that do not remove colloidal material. It has been shown in experiment^^^ on the solubility of hydrous ferric oxide in sea water that there is about an order of magnitude difference in the concentration of iron passed by a 0.45 ,um filter as compared with a 0.05 ,um filter. The operational definition of the dissolved fraction by conventional methods using filters with pore diameters about 0.45 pm is thus especially unsatisfactory for iron. Measurements of iron in surface waters of various regions61 gave a mean concentration of 25 nmol I-', similar to that found in the same study for waters nearer to the continents. A mean value of dissolved iron of 32 nmol I-' was reported 'O for Central Atlantic water upwelling in the Nova Scotia region; although there was a reservation that this value could include an uncorrected blank contribution of 9 nmol 1-' the results suggested little difference in concentration of iron between this water mass and the shelf and slope waters. For samples covering depths to 3 km in the Iceland-Faroe Ridge region, a mean value of 16 nmol I-' has been given;62most values were within the limits of analytical error about this mean, nmol I-'. A wide range of concentrations although the overall range was <4-145 (3-180 nmol I-') has also been found63for samples from profiles in the Indian Ocean, but excluding a few high values the mean was 8 nmol I-' with a standard deviation of 5 nmol I-'. Thermodynamic calculation^^^^^^ show that in sea water containing free oxygen, Fell1 is the strongly favoured oxidation state but that Fe" is the stable oxidation 9'G.T. F. Wong. Mar. Chem., 1980,9,1. 90 R. H. Byrne and D. R. Kester, Mar. Chern., 1976,4,255. 99

D. R. Kester, R. H. Byrne, jun., and Y.-J. Liang, in 'Marine Chemistry in the Coastal Environment'. ed. T. M. Church, American Chemical Society, Washington. DC, 1975, pp. 56-79.

25 8

Environmental Chemistry

state in sulphide-containing waters. measurement^^^ of the rate of oxidation of Fell showed that for water from the Sargasso Sea, in equilibrium with atmospheric oxygen, the time required to halve the concentration of Fe" was 3.3 min at pH 8 and 330 min at pH 7. The rate constant was approximately twice that for coastal water but about two orders of magnitude below that expected on the basis of other measurements on sodium bicarbonate solutions. The reduction of iron in sulphide-containing waters is reflected in the dissolved concentrations, which are much higher than those in dioxygen-containing waters. Concentrations of Fe" have been shown58to increase markedly below the interface of the oxygenated and anoxic layers in Saanich Inlet, reaching a maximum concentration of about 1 pmol I-'. In the water column overlying the Cariaco Trench93the concentrations of dissolved iron increase from about 180 nmol kg-1 in the.oxygenated waters, which extend to about 250 m, to a maximum of about 450 nmol kg-' around 500 m. The dissolved concentrations show a decrease in the deeper waters, accompanied by an increase in particulate iron, probably reflecting the precipitation of ferrous sulphide. Kester and c o - w ~ r k e r have s ~ ~ used ~ ~ ~their measurements of stability constants for important FeIII species to derive an equilibrium model for the inorganic speciation of Fe"'. They find Fe(0H); to be the dominant species formed with the ligands considered (OH-, C1-, SO:-, F-), at pH 8.0, with Fe(OH),f accounting for ( 5 % of the total. The treatment of Fe(0H); as a complex in solution in the model does not exclude the possibility that the iron thus represented may be colloidal, since in the determination of the stability constant the species is characterized operationally and could include small colloidal as well as truly dissolved forms. In Ahrland's calculations," Fe(0H); was not included, for lack of data. He calculated Fe(OH),f to be the dominant species, but estimated the concentration of this species in equilibrium with solid FeO(0H) to be only mol I-', i.e., considerably below measured concentrations of iron in sea water, consistent with the view that dissolved Fe(0H); or a dispersed hydroxyoxide phase is the dominant form. Zafiriou and True'OO have derived rates for the interconversion of Fe(0H); and Fe(OH),f. They conclude that this process is rapid in sea water and that Fe(0H); is unlikely to form a major fraction of the mononuclear species of iron. According to Lu and Chen,31 Fe(0H); is the major species, although Byrne and K e ~ t e r ~ ~ consider it to be of no importance. The speciation of Fe" in sea water at pH 8 is dominated by FeOHS (88%) with only 4% as the unassociated cation, according to Kester et ~ 2 1Davison's .~~ model'O' gives a completely different description of the speciation with 75% as hydrated Fez+ and < 1% as FeOH+. The importance of the unassociated cation is indicated also in the model of Morgan and Sibley.28Sulphide associations have not been evaluated in these calculations. .~~ Organic ligands were considered in the calculations by Kester et ~ 2 1 Although they are not significant for either oxidation state in equilibrium systems, their possible significance in environmental systems remains to be assessed. Organic associations of FeI1 provide one possible explanation of the retardation of its showed that a large fraction of the oxidation rate in sea water.99Sugimura et loo lo'

Io2

0.C. Zafiriou and M. B. True, Mar. Chem., 1980,8,28 1. W. Davison, Geochim. Cosmochim. Acta, 1979,43, 1693. Y. Sugimura, Y.Suzuki, and Y. Miyake, Deep-sea Res., 1978,25,309.

Constituents in Ocean Waters

259

iron in filtered ocean water was retained on the macroreticular resin XAD-2 and interpreted this to indicate the presence of the element in organically associated forms.

Cobalt.-Daniel~son~~ analysed for cobalt in unfiltered samples from various depths in the Indian Ocean. Concentrations were usually below the limit of detection, which was either 50 or 170 pmol 1-' in different series of measurements: the range was from <50-270 pmol I-'. Detectable concentrations were found only in the upper part of the water column, above 500 m. These concentrations are lower than most of those determined previously although some similar values have been reported. For samples of oceanic, slope, and shelf waters off Nova Scotia a mean concentration of 270 pmol I-' was found,70but a considerable proportion of the samples had concentrations less than the limit of detection of 120 pmol 1-'. Values measured37on several profiles in the western Atlantic Ocean showed unsystematic variations in concentration with depth, from .around 100 pmol 1-l to >680 pmol I-'. Concentrations were more uniform and low, however, in a profile near the Antarctic, with values in the range of 85-150 pmol I-' at many of the depths sampled. Higher concentrations than those found in the studies discussed above have been reported for the northwestern Atlantic Ocean. l 6 Recent developments concerning other trace metals suggest that a systematic pattern in the distribution of cobalt should become evident with the application of more sensitive techniques to samples collected with rigorous attention to contamination problems. There is disagreement between the several equilibrium ion association models for the speciation of cobalt in sea water, partly due to the lack of information on the stability of carbonato complexes. Ahrland21 estimates Co2f (54%) and CoCl+ (3 1%) to be the most important species. Chloro complexes appear as the dominant ~~ species in the model of Morgan and Sibley.28A more recent c a l ~ u l a t i o nsuggests, however, that CoCO! is the most important species, with a considerable fraction also of unassociated cations but a negligible fraction of CoCI+. Nickel.-Sclater et aZ.'03 found values, determined on samples from four GEOSECS profiles in the Atlantic and Pacific Oceans, which were more than five times lower than those previously reported. Concentrations ranged from 3 nmol kg-' in surface waters to 12 nmol kg-' in deep North Pacific Ocean waters. The distribution relative to those of micronutrient elements suggested that the transport of nickel in association with biological material involves components with shallow and deep regeneration cycles. Although analyses of some samples collected prior to 1975 gave higher value^,'^*^' the low values were supported by less detailed In the information for the Sargasso Sea69and by data for waters off Nova Sc~tia.~O latter region, upwelling Central Atlantic water was found to have an average concentration of 4 nmol 1-', and similar values were found for the slope and shelf waters. The findings of Sclater et a1.Io3were confirmed by subsequent measurements in the northeastern Pacific Ocean.60The distribution of nickel in this region in relation Io3

F. R. Sclater, E. Boyle, and J. M. Edmond, Earth Planer. Sci.Lett., 1976, 31, 119.

Environmental Chemistry

260

to those of the micronutrients was best described by the multiple regression equation: Ni(nmo1 kg-') = (0.95 f 0.08) PO,(pmol kg-l)

+ (0.033 k 0.001) Si(pmo1 kg-') + 2.74

with r = +0.995. For surface waters there was a decrease in concentration from 3.7 nmol kg-' in the California Current to 2.1 nmol kg-' in the central oceanic region, which paralleled the changes in concentration of phosphate. Results for one station in the Pacific Ocean have been used6g in an advection-diffusion model to estimate the scavenging residence time for nickel; a maximum value of 1.6 x lo4 yr was obtained, intermediate between the values for copper and cadmium. Data for the Indian Ocean63 fit well into the above picture with average concentrations of 5.1 2 1.5 nmol 1-' in waters above 100 m and 9.4 & 3.1 nmol I-' for deeper waters. The deep water concentrations are, as expected on the basis of a close relationship with the micronutrients, intermediate between those for the deep Atlantic and Pacific Ocean waters. In the Indian Ocean, however, a clear correlation of nickel with micronutrients was found for only two out of five stations and for these the correlation with silicon alone was closer than that with phosphate or nitrate, or with those nutrients in combir,ation with silicon. According to the equilibrium ion association model of Ahrland2' the speciation of nickel is very similar to that which he estimated for cobalt, with 53% present as Ni2+ and 31% as NiCl+. A similar importance for these two species is indicated by Lu and Chen,31 but Morgan and Sibley28 calculate chloro complexes to be dominant. As with cobalt, Mantoura et al.64suggest a far greater importance for the carbonato complex, the main species in their model being NiCO! (-50%), NiC1+ ( 20%), and Ni2+( 20%). N

-

Copper.-In the early 1970s the typical concentration of copper in oceanic waters was thought to be about 15 nmol I-'. Many values from analyses of surface and deep samples collected at that time were in this although lower values with a geometric mean concentration of 4 nmol 1-' were reported for samples from the shelf west of Scotlandg9 and most of the samples collected from the Iceland-Faroe Ridge area62gave values of 3-6 nmol 1-'. Boyle and EdmondIo4 reported concentrations of 1-3 nmol kg-' for surface waters south of New Zealand to 69"s. This region shows clear changes in surface concentrations of nutrients as a consequence of upwelling, and a significant positive correlation ( r = +0.88) of the concentrations of copper and nitrate was found. Measurementslo5 on samples from the eastern Atlantic Ocean between 23"N and 47"N gave concentrations of 1.4-3.6 nmol I-', and variations with depth which, although not pronounced, suggested a slight depletion in the euphotic zone relative to underlying waters. Similar values were found69 in the Sargasso Sea with estimated probable concentrations of 1.9 nmol kg-' for surface waters and 2.4 nmol kg-' for waters between 1.8 and 4 km. A mean value of 6 nmol kg-' was reported70 for waters off Nova Scotia. Io4 Io5

E. Boyle and J. M. Edmond. Nature (London), 1975, 253, 107. R. M.Moore and J. D. Burton, Nature (London), 1976, 264. 242.

Constituents in Ocean Waters

26 1

Six detailed profiles in the Pacific Ocean were examined by Boyle et aLzoThere were considerable differences in distribution in the top 1 km, but all showed an increase in concentration from intermediate to bottom waters. In the Central Pacific gyre region a clear subsurface minimum occurred, as shown by the example in Figure 8. Concentrations were in the range 2.4-3.5 nmol kg-' in surface waters, decreased to as little as 1.5 nmol kg-I in the minimum zone, extending to 500-750 m, and then increased markedly to 1 km, with further increases in the bottom water to 6-9 nmol kg-'. In the boundary regions, a surface maximum was not found.

C u/n mo I kg-' 0

2

4

6

8

10

0 0

0

0

1

.

.......

0..

0

.

*......

*...........4 2

0

E

0 .

5 n

0

A --.

n

3

0

8 0

0

4

0 0.

5

Figure 8 Distribution of copper in the North Pacific Ocean ( 10°28'N, 123O38'W). Connected points are replicates of the same sample. (Redrawn from a figure in Earth Planet. Sci. Lett., 1977, 37, 38: with permission of Elsevier ScientificPublishing Co.)

The authors attributed the enhanced surface concentrations observed in some profiles t o input from the atmosphere. These distributions show only a general resemblance to those of the micronutrients. At four stations the characteristics of mixing in the deep water allowed the application of a steady-state one-dimensional advection-diffusion This indicates an input of copper into the deep water which is considered to result from diagenetic release of copper from settled particles which have previously taken up the element from the water column. Brewer and Hao68have recalculated the scavenging rate constant obtained from this model to take account of the fact that in the deep water there occur simultaneously the release of copper by '06

H. Craig, Earth Planet. Sci.Lett., 1974, 23, 149.

26 2

Environmental Chemistry

decomposition of biogenous particulate material and scavenging of the element by other particles. The scavenging residence time estimated in this way is 1 . 1 x lo3yr. Most of the findings of the above study are reinforced by measurements6" on additional profiles in the northeastern Pacific Ocean. In this work there was, however, no evidence of enrichment in the mixed layer and it was suggested that the earlier surface values may have been affected by contamination. The surface concentrations decreased from 1.2 nmol kg-' in the California Current to 0.4-0.5 nmol kg-I in the central oceanic region. As with nickel these changes were correlated with those in phosphate. Further measurements lo7 on the eastern North Atlantic Ocean also show consistently a depletion in the upper water column with concentrations from 1.1-1.7 nmol 1-1 and no indication of significant surface enhancement. These profiles commonly showed an intermediate maximum at depths of 250-500 m. Increases in near-bottom water were observed and their magnitude was related to the nature of bottom sediments. Maximum concentrations were about 10 nmol I-' over red clays; less pronounced increases were observed for bottom waters overlying calcareous sediments. Values for surface waters in the Blake Plateau region of the Atlantic Ocean have been reported lo* to average 3.1 nmol kg-' ; Gulf Stream waters in the same latitudes contained on average 2.2 nmol kg-I, and the adjacent shelf waters showed similar or lower concentrations. The mean concentration of copper in surface waters of the Indian Ocean has been reported63 t o be 3.6 & 0.5 nmol I-'. Northernmost stations (4OS-19ON) showed a minimum in concentration at about 200 m followed by a steady increase with depth: concentrations of copper and silicon were closely correlated for samples below 150 m but surface samples were higher in copper than would have been predicted on this basis. Further south ( 10-15°S) the subsurface minimum was not found and the mean concentration below 100 m was similar to that in the upper layer. There has been little agreement among the various equilibrium ion association models proposed for the speciation of copper in sea water. The numerical values from three models are given in Table 3: the reasons for differences of the kind

Table 3 Percentage distribution of copper between its principal inorganic species in sea water Cu2+

CuOH'

Cu(OH)!

CuCl+

Cu(0H)CI"

CuCO!

Ref.

0.7 17 0.3

4 22

-

6 10

65

22 49

1

94

27 21 10

-

0.4

-

4

shown have already been outlined in the section on lead. A major difference is the importance of the mixed ligand complex Cu(0H)ClO considered in the model of Dyrssen and W e d b ~ r g . *This ~ model, with that of Florence and Batley30 indicates that the fraction of unassociated cupric ions is < 1%. All other speciation models, except that of Ahrland2I agree that the free cation is a minor species but there are wide differences otherwise. Morgan and Sibley 28 calculate the chloro complexes to I"'

lo'

R . M . Moore, Earth Planer. Sci.Lett., 1978, 41,461. H. L. Windom and R. G. Smith, jun., Mar. Chem., 1979. 7, 157.

Constituents in Ocean Waters

263

be the dominant species, whereas Lu and Chen3' estimate complexes with borate and carbonate ions to be of major importance. The models of Long and an gin^^^ and Mantoura et af.64agree in showing Cu(0H); to be the dominant species. The latter model considers humic material and the results suggest that at equilibrium copper is the only metal of those considered which is complexed to a significant extent with this material, some 10% occurring thus. working on northeastern Atlantic Ocean waters, measured Moore and the fraction of dissolved copper, which was made analytically available by photo-oxidation, and that which was extractable into chloroform ; each accounted found that much of the for at most 10% of the total copper. Sugimura et dissolved copper in surface waters from the western North Pacific Ocean was adsorbed on the macroreticular resin XAD-2 and this was interpreted as indicating a correspondingly high degree of organic association. Lu and Chen3' calculate that in sulphide-containing waters the only significant species formed by Cu" is Cu(HS);. Ahrland's calculationsz1indicate, however, that Cu" will be reduced at the p E of such a system. Molybdenum.-Analyses have been reported83 of molybdenum in surface waters and subsurface waters from depths up to 1 km in the northeastern Atlantic Ocean. Concentrations lay in a narrow range of 90-135 nmol I-' with a mean of 110 nmol I-'. No systematic variations with location or depth were found and the average ratio of concentration of molybdenum to salinity was less than 2% higher than that found in the same study for surface coastal waters from the eastern Irish Sea. Measurements of molybdenum have also been made79on surface waters on a section from Great Britain to Barbados and in the eastern Caribbean Sea, and on samples from two vertical profiles in the Tobago Basin and one in the mid-ocean ridge region; the deepest sample was taken below 3 km at the latter station. The range (95-135 nmol I-') and mean (1 15 nmol l-I) are almost identical with those found for the higher latitude region investigated by Morris.83These data agree with the majority of earlier findings that molybdenum is a relatively abundant trace constituent which behaves rather conservatively in the ocean. Silver.-The average concentration of silver in profiles from the western Atlantic Ocean has been reported37 as about 45 pmol l-l, with individual samples ranging from 4-185 pmol 1-I. Ahrland's equilibrium ion association modelz1indicates the most important species to be AgC1:- (54%), AgCIi- (24%), and AgCl, (1 7%). Gold.-The speciation of gold has been considered by Ahrland.zl At p E 12.6 Aul is the dominant oxidation state. Its major species is AuCl,, which accounts for 94% of the total, with AuClBr- amounting to 6%. The calculations suggest that metallic gold may be formed at lower pEs.

3 Additional Aspects of Chemical Speciation The chemical speciation of the minor elements has been studied almost entirely by the use of ion-association models. These models can provide values for the fraction lo9

Y. Sugimura, Y . Suzuki, and Y.Miyake, J. Oceanogr. Soc. Jpn, 1978, 34, 93.

264

Environmental Chemistry

of the total concentration that is present as the uncomplexed ion, and, by use of an estimated free-ion activity coefficient, the activity of the ion can be calculated. WhitfieldI'O has used an alternative method in applying the specific ion interaction approach of Bransted and Guggenheim, and the ionic interaction equations of Pitzer, t o estimate the total single-ion activity coefficients for several minor ions in sea water. For the trace metals, however, various interactions, which the ion-association models show to be important, were not considered for lack of experimental data. A value for the p E of oxygenated sea water of about 12.5 has generally been assumed in modelling oxidation-reduction equilibria, this corresponding to the oxidation-reduction potential for the oxygen-water redox couple at pH 8.1. There is considerable debate, however, as to whether this assumption is appropriate and, indeed, as to whether modelling on the basis that other couples are poised by a single dominant couple in sea water is meaningful. It is apparent that kinetic factors are important in determining whether or not there is a significant persistence in the environment of an oxidation state, which is thermodynamically unstable, once it has been introduced from an external source or by in situ biological processes. This has been illustrated in the previous discussions of arsenic, selenium, iodine, chromium, and manganese. It is nevertheless useful, if it can be done, to establish the equilibrium speciation that provides a boundary condition against which to consider environmental observations. Breck ' has considered the equilibrium speciation of various elements at different pEs. He suggested that a p E lower than 12.5 such as might arise through control by the oxygen-hydrogen peroxide rather than the oxygen-water couple, is more compatible with observed speciations. emphasizes the likely role of hydrogen peroxide and the probability that the redox potential of sea water is a mixed potential. The limitations of measurements of redox potential in terms of quantitative interpretation of oxidation-reduction behaviour in such a system have been discussed by Stum111.l'~ In previous sections attention has been drawn to the difficulties in modelling the equilibrium distribution of metal ions between the various ligands with which they form complexes in sea water. Experimental data on the forms present in open ocean waters is almost wholly lacking. A few approaches have been indicated in previous sections. Sugimura et u1.'09 have extended to a range of metals their attempt to use the macroreticular resin XAD-2 to separate organically associated forms. For coastal waters significant fractions of some metals are not immediately reactive in terms of analytical procedures, such as ion exchange on chelating resins, electrodeposition at mercury electrodes, and solvent extraction following chelation. Operationally defined fractions of metals have been measured in terms of changes in analytical availability following various treatments such as photo-oxidation and

'In Ill

'I2

M. Whitfield, Geochim. Cosmochim. AcIa. 1975, 39, 1545. W. G. Breck, in 'The Sea. Volume 5: Marine Chemistry', ed. E. D. Goldberg, Wiley-Interscience. New York, 1974, pp. 153-179. R. Parsons in 'The Nature of Seawater', ed. E. D. Goldberg. Dahlem Konferenzen. Berlin. 1975, pp. 505-522; R. Parsons, Thalassia Jugosl.. 1978. 14. 193. W. Stumm, Thalassia Jugosl.. 1978, 14. 197.

Constituents in Ocean Waters

265

acidification. These approaches are exemplified in several 'I4 and have been reviewed by Florence and Batley.115 The equilibrium model of Mantoura et al.64 suggests that complexation of trace metals by humic materials in sea water is negligible for zinc, cadmium, mercury, manganese, cobalt, and nickel, and is minor for copper. Studies with model ligands, summarized by Raspor et ul.,'l6 also suggest that the formation of complexes with recognized ligand types is not significant for zinc, cadmium, and lead. There is thus considerable uncertainty as to whether analytical observations are to be interpreted in terms of the occurrence of dissolved organic complexes or of associations with organic and inorganic colloidal material. For copper it has now been possible to obtain less equivocal evidence for an organically associated fraction of the element in waters from Narragansett Bay117and the Baltic Sea.118 There is at present a contrast in the status of work on near-shore and oceanic environments, as regards the trace metals. For the open ocean, rigorous attention to contamination control has led to a major advance in the availability of high quality data on distributions but experimental work on chemical forms, apart from the study of oxidation states, has scarcely begun, not surprisingly in view of the effort that has been required to obtain the present data. For coastal waters, more work has been undertaken on chemical forms but there is a need to re-examine the status of data on the occurrence of some elements in the light of the recent advances for oceanic waters.

'I4

J. C. Duinker and C. J . M. Kramer. Mar. Chem., 1977, 5, 207: H. W. Nurnberg. P. Valenta. L. Mart,

B. Raspor, and L. Sipos. Fresenius' Z. Anal. Chem., 1976, 2 8 2 357: G. E. Batley and T. M. Florence, Mar. Chem., 1976, 4, 347: G. E. Batley and D. Gardner. Estuarine Coastal Mar. Sci., 1978, 7,59. 'Is T. M. Florence and G. E. Batley, Talanta, 1977, 24, 15 1; T. M. Florence and G. E. Batley, Crii. Rev. Anal. Chern., 1980, 9.219. ' I h B. Raspor, H. W. Niirnberg. P. Valenta, and M. Branica in 'Lead in the Marine Environment'. ed. M. Branica and Z. Konrad, Pergamon Press, Oxford, 1980, pp. 18 1 -195. ' I 7 G . L. Mills and J . G . Quinn, Mar. Chem., 198 1. 10.93. 'IxK. Kremling, A. Wenck. and C. Osterroht, Mar. Chem.. 1981. 10. 209.

Author Index Aalund, 0..2 I6 Aaran, R. K., 85 Abbazov. M. A., 201 Abd-Elfattah, A., 142 Abel, J., 59 Abel, R. H.. 37 Abelson, P. H., 97 Abbott, D. C., 79 Abu-Erreisch, G. M., I93 Ackerman, E., 12, 13 Acquaye, D. K.. 100 Adamis, Z., 59 Adams, D. B., 9 3 Adams, F. C., 15, 19 Adams, J. A. S., 96, 196 Adams, S. N., 133 Adamson, A. H.,. I72 Aderikhin, P. G., 100, 122 Aferov, Yu. A., 149 Agarwal, S. K., 157 Aharonson, E. F.. 57 Ahlberg, M., 15, 26 Ahmad. I., 148 Ahmad. N., 100 Ahmad, S., 148 Ahmed, A., 5 1 Ahn, P. M., 94 Ahrens, L. H., 114, 115, 195 Ahrland, S., 238 Ahuja, S., 72 Aibara, K., 23 1 Aidin'yan, N. Kh., 15 1 Aikawa, J. K., 79 Ajl, S. J., 206, 2 16 Akselsson, R., 15 Alakuijala, P., 13 Albert, R. E., 59 Alberts, J. J., 57, 152, 237 Aleksakhin, R. M., 200 Aleksandrov, A. M., 127 Alekseev, Yu.V., 197 Aleskovskii, V. B., 113 Alessio, L., 29 Alexander, F., 8 1 Alexander, M., 193 Alfoldi, T. T., 10 Alfrey, A. C., 8 1 Alkezweeny, A. J., 23, 26, 27 Allan, R. J., 53 Allaway, W. H., 125, 192, 194 Allcroft, R., 181 Allee, P. A.. 67 Allen, T., 7 Allison, A. C., 58

Alloway, B. J., 139, 171, 190 Aloia, J.. 8 4 Altenkirk, B., 2 13 Altshuler, B., 57 Amano, R., 2 16 Ames. B. N., 2 12 Amiel, S., 16 Ananyan. V. L., 200 Ancizar-Sordo, J., 7 1 Andersen, A., 14 Andersen, 1.. 8 I Anderson, A. J., 125 Anderson, B. J., 147 Anderson, D. L.. 16 Anderson, E. C., 62 Anderson, G., 176, 178, 203 Anderson, J. A., 42 Anderson, J. E., 9 Anderson, M. S., I94 Anderson, R. A., 233 Andersson, A., 124, 127, 133, 135, 137, 141, 144, 152. 154, 169 Andreae, M. O., 72,238,241 Andrellos, P. J., 228, 232 Andren, A. W., 36,49, 57 Andres, S., 59 Anfalt, T., 15 1 Angel, C. N., 8 1 Angel, M., 250 Angino, E. E., 240 Anlauf, K. G., 27 Aomine, S., I52 Apling, A. J.. 4 I Appel, 9. R., 6, 17, 2 7 , 4 1 Aranyi, C., 59 Araratyan, L. A., 99 Archer, F. C., 94, I39 Ardakani, M. S., 138 Arduino, E., 17 1 Aripova, Kh., 149 Arkhipov, N. P., 200 Arkley, R. J., 103, 121, 127, 130, 133, 135, 137, 141, 157. 158 Armands, G., 198 Armstrong, A., 10 Armstrong, D. E., 57 Arnaud, S. B., 84 Arnold, A., 184 Arnold. E., 13 Arnold, M., 34 Arnott, J. T.. 190 Aronson, A. L., 173

Arsac, F., 59 Artem'eva, K. A.. 122 Arvik. J. M., 170 Asabe. Y.. 220 Asami, T.. 101 Asher. M.. 13 Ashton, W. M.. 135 Ashworth. L. J., 220 Asmussen, C. R., 79 Aston, S. K.. 235 Asvadi, S., 58 Atanasov, 1.. 94 Atkins, D. H. F.. 3 I Atkinson. H. J., 127, 133, 137, 141, 169 Au, F. G. F., 153 Aubert. H., I6 1 Auclair, D., 6 I Auslous, P. J., 25 Austenson, H. M., 154 Austin, M. P., 127, 137, 14 I Austwick. P. K. C., 216 Auvermann, H. J., 9 Avetisyan, A. S., 200 Axelsen, N. H., 2 16 Axley, J. H., 190, 191 Ayer, R. S., 100 Ayers, G. P., 12 Ayers, J. L., I89 Ayoade, J. O., 68 Ayres, J. C., 233 Azzaria, L. M., 153 Babcock, K. K., 150 Babu, S. P., 36 Bach, W., 1, 36 Bache, B. W., 178 Bache, C. A., 146 Bacon, J. R., 98, 100. 101, 116, 118 Bacon, M. P., 256 Badanur, V. P., 142 Bagley, E. B., 233 Bailey, D. E., 209 Bain, D. C., 33, 107 Baird, R., 8 0 Baker. C. W., 25 1 Baker, D. E., 139 Balaguru, T., 12 1 Balashov, Yu, A., 1 15, I I6 Balassa, J. J., 80, 81, 89 Baldwin. B., 66 Ball, D. J., 41, 64

A ut hor Index

268 Baltakrnens, T., 200 Bannink, D. W., 152 Barakso, J., 151, 190 Baranova, V. I., 197. 199 Barber, F. R., 54 Barber, J., 36 Barber, S. A,, 106 Barchet, R., 8 0 Barcome, D. F., 79 Barkes, L., 193 Barnard, W. M.. 19 I Barnes, M. E., 150 Barnes, R. A., 30,42 Barnhisel, R. I., 139 Barone, J . B., 64 Barragan Landa, E., 94, 121, 127, 130, 137 Barret, C. B., 232 Barrett, E. W., 64 Barrie, L. A., 27, 64 Barringer, A. R., 36 Barron, V. J., 89 Barry, P. T., 50 Barshad, I., 20 I Barth, T. F. W., 96 Bartholomew, W . V., 174 Bartlett, R. J., 125 Baser, B. L., 157, 176 Bastron, H., 117, 149 Bate, L. C., 49 Batley, G. E., 238, 240.265 Battaglia, 0. C., 12 1 Baudet, J., 35, 36 Bauer, A., 142 Bazzaz, F. A., 50 Beamish, F. E., 148 Beamish, R. J., 54 Bear, F. E., 94, 103, 109, 174 Beath, 0. A.. 70, 194 Beaton, J . D., 177 Beauford, W., 36 Beavington, F., 20, 54. 6 1 Beck, R. H.. 54 Beckert. W . F., 153 Beckett. P. H. T.. 97 Beckwith, A . C., 232 Beerthuis. R. K., 232 Beeson. K . C., 194 Beg. M . U.. 59 Begnoche. B. C., 17 Belhall, K. M.. 79 Bell, J . P.. 9 Bell, K . A.. 59 Belling, G. B.. I92 Belozerov. E. S., 8 I Belyaev. A. B., 100 Benarie. M. M., 3 Ben-David, A.. 57 Bender. M. L., 250. 253. 254, 256 Bcnham, D. G., 6 Bcnsirnon, J., 65 Bcrdnikova, A. V.. 70 Berg. W . W .. 2 I Bcrger. I . A.. I 13

Bergstrorn, R., 5 9 , 6 3 Berkowicz, R., 46 Bernacki, E. J., 8 I Bernard, R. E., 64 Bernstein, D. M., 8, 52 Berrow, M. L., 95, 98, 99, 100, 101, 103, 105, 106, 107, 109, 112, 122, 125. 128, 130, 138, 144, 155, 156, 159, 170. 193 Berry, G., 59, 2 18 Bertine, K. K., 146 Bertrand, D., 100 Bertrand, G., 100 Bethea, N. J., 173 Bethea, R. M., 173 Bettany, J . R., 177 Betzer, P. R.,37, 256 Beuge, P., 190 Bexon, R., 10 Beyermann, K., 8 0 Beyers, C. P. de L., 137 Bhan, A. K., 199 Bhandari, J . R., 2 15 Bhargava, B. S., 141 Bhargava, G. P., 98 Bhat, R. V., 2 15 Bhatnagar, R. K., 100, 137, 141 Bhumbla, D. R., 122 Biermann, A. H., 8, 36, 37 Biermann, J., 8 0 Bigg, E. K.. 4, 27,47 Biggins, P. D. E., 39 Biles, B., 5 Bilkiewicz, J., 32 Billings, C. F., 154 Bingefors, S., 194 Bingham. F. T., 142, 143, 145, 156, 157 Bing Yeh, 106, 107, 109, 112. 121. 124, 127. 133. 135, 137. 141. 157, 168. 169 Bird. E. D., 8 1 Birks, L. S.. 15 Bisbjerg, B., 192 Bishop, G. D.. 10 Bishop, R. F., 14 I , 189 Biswas, T. D., 127. 130. 137. 141. 157 Black, C. A., I74 Blair. F. L.. 103. 121, 127. 130. 133. 135, 137. 141. 158 Blakemore. L. C.. 130. 158 Blamont. J . E.. I 1 Blanchar. R. W.. 190 Blaxter. K . L.. 194 Bleeker. P.. 127, 137, 141 Blokker. P. C.. 5 Bloom. H.. 29 Bloorntield, C.. 1 I3 Blotcky. A . J.. 8 I Blount. M . C.. 103 Blurn. W . E.. 170 Boback. M. W.. 8 I Bdvikcn, B.. I7 I

Boerngen, J . G . . 98. 101 Boggess, W. R.. 172. 173 Bogui, V., 35 Bohn, H. L.. 164 Boiteau, H. L., 89 Bolin, B., 65 Bolger, G. W., 256 Bolton, J., 98 Bolton, N. E., 36 Bondar, P. F., 200 Bongaarts, P. M., 8 1 Bonsang, B., 20 Bontje. J. A., 28 Boose. C., 4 Booth, R. S., 6 3 Boppel, B., 80 Boratynski, K., 125, 129 Borchardt, G. A., 116 Borg. K., 154 Bormann. F. H., 52 Borys, R. D.. 6, 33 Bos, F., 1 1 Bostrom, H., 8 0 Boswell, C. R., 125, 171 Bothast, R. J., 220 Boudene, C.. 59 Bouley, G., 59 Bourgeois, C. H., 2 15 Boussicault, C., 89 Boutron, C.. 53 Bowen, H. J. M., 48.49, 71, 79, 101, 199 Bowen, V. T., 1 18 Bower, J . S.. 4 1 Bowles, J. M., 98. 101 Boyd, E. M.. 82 Boyle. E. A.. 249. 258.259, 260 Boyle, J . R., 100 Boyle, R. W., 146. 149, 150. I94 Brachaczek, W . W.. 5.40 Bradford, G. R., 98. 103, 21, 127. 130. 133. 135. 137. 41. 158 Bradley, R. I . , 100. 106, 10. 117. 127. 130, 135, 137. 4 I. 144. 169. 185. 189 Bradley. R. S.. 66 Brady. N . C., 100 Braekke. F. H., 54 Braharn, R . R.. 67 Brain. J . D.. 57 Brakhnova. I. T.. 58 Brarnan. R. S.. 72. 153. 24 I Brandenstein. M . 1.. 195 Brandone. A., 79 Brandt, M.. 40 Branica. M.. 238. 240. 265 Brar. S. S.. 1 I6 Bratishko. R. Kh.. I I6 Brauner. P. A.. 234 Breck. W . G.. 264 Breger. 1. A.. 196 Brcmner. J . M.. 174. 178 Brendakov. V. F.. 99. 200

Author Index Bretthauer, E. W.. 153 Brewer, P. G., 234, 245, 246, 249,256 Brewer, R. F., 172, 181 Brewers, J . M., 250 Briat, M., 32 Bridgman, H. A.. 26, 63 Briehl, D., 22 Briggs, A.. 29 Briggs, E., 6 1 Brimblecombe, P., 1, 10 Brinckmann, F. E., 85 Brink, V . C., 120 Brockhaus, A., 59 Brodanova, M.. 8 1 Brody, A., 12 Broecker, W. S., 236 Broenkow. W . W.. 249 Bromfield, S. M., 142 Brooks. J . D., 150 Brooks, R. R., 110, 122, 123. 125, 135, 171, 195 Brooks. S. M., 58 Brooks. W. L.. 1 Browell, E. V.. 42 Brower, D. L., 145 Brown, C. M., 220 Brown, D. H.. 135 Brown, E. D.. 80 Brown. G., 165, 198 Brown. H., 8 1 Brown, R. M., 3 1 Brown, S. S.. 80, 81. 89. 93 Browning, E., 12 Browning, K. A.. 53 Browning, S. R.. 65 Broyer. T. C.. 172 Bruch, J.. 59 Bruckman, L., 6 1 Bruger. M., 8 1 Bruland, K. W.. 246. 249. 254 Brune. D.. 80 Brunelle. M. F.. 3 1 Bruyere. S.. 59 Bryce. D. J., 6 1 Buat-Menard. P.. 34 Buchanan. M. L.. 154 Buckle. A. E.. 209. 222 Buckley. D. 1.. 38 Buckman. J.. 8 I Budyko. M. 1.. 65 Buehler. M. H.. 181 Bujdoso. E.. 85 Bulman. R . A.. 201 Bunker. C. M.. 198 Bunton. N. G.. 80 Buonicore. A. J.. 2 Buraiky. M. S.. I54 Burger. J.. 57 Burger. R. du T.. 142 Burk. R. F.. 89 Burkov. V. V.. I I6 Burnett. M.. 56 Burns. G. R.. I77 Burns. K. N.. 18 I

269 Burns, R., 89 Burr, J. C., 5 Burridge, J . C., 94, 95. 125. 138 Burrows, W. D., I50 Burstall. F. H.. 114 Burton, J. D., 151. 242. 250. 260 Burton, M. A. S . . 14 Bus, J . S., 58 Buschbom, R. L., 59 Bush, A. W.. 6 Bush, C. A., 198 Buss. D. H., 79, 80 Busse, A. D., 45 Butcher, S. S., 38 Butler, D. M., 66 Butler, J . R., 10.5, 117. 168. 169 Butler. J . W., 40 Buzzard. G. H., 9 Byrne. A. R., 80.8 1 Byrne, R. H.. 242. 257 Bysiek. M., 32 Cadle. R. D., 8, 12. 21. 22. 35. 41 Cadle. S. H., 46 Cahill. J. P., 98 Cahill. T. A.. 64 Caldecott. R. S.. 9 1 Caldwell. A . C.. 177 Caldwell. W., 12 Calliere. S., 116 Calop. J., 58 Calvert. S., 63 Cambiaghi. G., 29 Cambray. R. S.. 7. 56 Cameron, D. R.. 184 Cameron. E. M.. 15 I Camner, P.. 59 Camp, W. J. R.. 81 Campbell. A. D.. 2 16. 2 18. 223 Campbell. J . A.. 37. 253 Campbell. T. C.. 2 15. 224 Cannon. H. L.. 95. 113. 149 Cannon. J . R.. 88 Cannon. W . C.. 59 Cantrell, A.. 6 Cara. J.. 44 Carbonneau. N.. 80 Carll. W. T.. 205 Carlson. R. W.. 50 Carlson. T. N.. 10. 65 Carnuth. W.. 1 I Carpenter. J. H.. 115 Carpenter. R.. 24 I Carr. R. A.. 250 Carr. T. E. F.. 80 Carrow. R. N.. 190 Carson. B. L.. 60. 93. 148 Carter. D. L.. 193 Carter. J. A,. 36 Carter. R. L.. 2 I6 Cartwright. B.. I 7 I Cartwright. G. E.. 8 1 Car?. E. E.. 125. 192. 193

Casagrande. D. J.. 203 Caschetto. S.. 237 Case, L. F., 81 Casia. J . E., 220 Castleman. A. W.. 22 Catani. R. I., 141 Cato. I.. 235 Cattell. F. C . R.. 34 Cautreels. W., 6 Caverly. R. S.. 65 Cawse. P. A., 1. 7. 17. 19. 20. 23, 50. 54. 123 Cederwall. R., 5 Cehak. K., 44 Cermak, J. E.. 8 Cerutti. P.. 227 Cerwenka. E., 90 Cess. R. D,.65 Chadwick. M. J.. 47 Chahal. H. S.. 3 Chamberlain. A. C.. 39. 50. 60 Chan. L. H.. 236 Chan. T. L.. 8 Chandavimold. C., 2 15 Chaney. R. L., 145. 146 Chaney. W. R.. 49. 144. 145 Chang. F. C. C.. 218 Chanin. M . L.. 11 Chao. T. T.. 147 Chapman. H. D.. 104. 139. 161. 168. 172. 181. 184 Chapman. S. B.. 202 Chappel. W.. 128 Chappell. W. R.. 80 Charlson. R. J.. 26. 41. 65 Chase. G. R.. 6 1 Chasteen. R. M.. 1 13 Chattopadyay. A.. 119. 144. 161

Cheam. V.. 15 1 Cheek. C. H.. 250 Cheh. A.. 72 Chen. K . Y . . 240 Cheng. B. T.. 122. 128 Cheshire. M. V.. 113. 128. 138 Chester. R.. 235. 246. 250 Chew. K.. 250 Childress. J . D.. 102 Childs. C. W.. 108. 117. 128 Chilko. D. M.. 17 1 Chinn. S. H. F.. 154 Chisholm. D.. 189. 190 Chitarov. N . 1.. 120 Chock. D. P.. 46 Cholak. J.. 81 Choquette. C . E.. 41 Choudhari. J. S.. 99 Chouhan. S. S.. 100 Chow. T. J.. 169. I 7 I Chow. V. T.. 179 Chrenekova. E.. 189. 190 Christensen. C. M.. 209. 220 Christian. G. D.. 7Y, 8 I Christian. R. P.. 8 I Christie. A. D.. 47

A u t hor Index

270 Chrustov, N. A., 191 Chu, F. S., 2 18, 232 Chu, W . P.. 22 Chuah. H. H.. 145 Chuan. R. L., 12 Chudecki, Z., 141 Chudyk, W., 72 Chung, Y.-C., 236 Church. T. M., 234, 257 Churkin. V. N., 99, 200 Chylek. P., 7 Cieglqr, A., 206, 2 13, 22 I , 230. 23 1 Cipley, J., 59 Clark. F. E.. 174 Clark. H. E., 79 Clark, W. E.. 28,4 I Clarke, A. G., 8 Clarkson, T. W., 85 Clayton, P., 5 Clayton, P. M., 145 Clayton, R. N., 32 Cleary, J. J., 80 Clement, C. R., 172 Clemente, G. F., 79 Clemesha, B. R., 1 I Cler, J . M., 89 Clifton, R. J., 80 Cline, J. A., 53 Clough, W. S., 15,60 Coakley, J. A., 65 Coates, J . P., 16 Cobourn, W. G., 17 Codifer, L. P., 233 Coffin, D. E., 80 Cohan, D., 68 Cohen, D., 33 Cohen, E. M., 72 Cohn, S. H., 84 Colbourn, P., 171, 190 Coleman, N. T., 157 Coleman, R. F., 80 Colley, P. J., 229 Collie. T. W., 177 Collis, R. T. H., I 1 Comar, D., 80 Comhaire, M., 133 Connor, J., 103, 112, 124 Connor,J.J., 111, 171 Consolazio, C. F., 80 Contour, J. P., 25 Conway, H. F., 233 Cook, H. A., 79 Cook, P. M., 6 1 Cooke, G. W., 97 Coomes, T. J., 232 Cooper, G., 5 Cooper, R. E., 6 1 Cooper, W. C., 90 Copenhauer, E. D., 153 Cordano, A., 83 Cordukes, W. E., 153 Corey, R. B.. 142 Cornelis, R., 79 Corneliussen, P., 79

Cornforth, I . S., 100 Correns, C . W., 180 Corrin, M. L., 67 Cosemans, G., 29 Cotic, I., 152 Cottenie, A.. 94 Cotton, W. R., 30 Couce, A . M. L., 141. 142 Coughtrey, P. J.. 145 Coulston, F., 59 Courbon, P., 4 Coutant, R. W., 6 Coutinho. A. S., 109, 141, 158 Covello, M., 190 Covert, D. S., 26 Cowgill, U. M., 118 Cowling, D. W., I77 Cox, G. E., 209 Cox, R. A,, 27 Coxon. D. T., 2 18 Coyle, P., 89 Cragin, J. H., 53 Craig, H., 26 1 Craighead, J. E., 12 Cranston, R. E., 246, 250, 252 Crawford, D. V., 138 Craxford, S. R., 6 1 Creasia, D. A., 58 Cress, T. S., 29 Crist, H. L., 37 Croce, E., 29 Crockette, J. H., 148 Crossman, G., 6 1 Crosby, N. T., 209 Cross, J. D., 79, 186 Cross, M., 6 Crowther, P. C., 232 Crozat, G., 35, 36 Crutzen, P. J., 2 1 Csupa, S., 201 Cucullu, A. F., 232, 233 Culkin, F., 250 Cullers, R. L., 116 Cunningham, P. T., 27 Curtin, G. C., 148, 149 Curtis, D. B., 36 Curtis, R. F., 2 18 Cushmac, M. E., 228,232 Cutter, G. A., 244 Czarnowska, K., 12 1 Daerbaev, A. A., 138 Dagle, G. E., 59 Dahlman, R. C., 39 Daines, R. H., I7 1 Dalager, S., 7 Dalal, R. C., 54, I76 Dale, 1. M., 79 Dale, J. M., 12 Dam, H., 194 Dams, R., 18, 19, 30 Daniel, H., 59 Daniels, A., 36 Danielsson, L.-G., 246 Dankert. W . N., 142

Dannevik, W. P., 5 1 Dantas, C. C.. 100, 101 Dantzman, J., 230 Dardenne, G., 138 Darley, E. F., 36, 6 1 Darmer, K . I., jun., 58 Darrow, D. K., 72 Da Silva, J . R. R. F., 93 Das Texieira, A. J., 109, 141, 158 Davenport, H. M., 52 David, D. J., 144 Davidson, A., 3 1 Davidson, A. W., 184 Davidson, C . I., 39, 5 1 Davidson, D. F., 195 Davidson, D. L.. 60 Davies, B. E., 145, 15 I , 17 1 Davies, C . N., 26, 63 Davies, M. K., 122 Davies, P., 59 Davies, T., 10 Davies, T. D., 30 Davis, J. F., 202 Davis, L. E., 37 Davis, N. D., 2 18, 220 Davison, W., 258 Day, J. P., 171 Day, N. E.. 218 Day, T., 38 De, S. K., 199 De Albuquerque, C. A. R., 162 Deb, D. L., 137, 141 Decker, A. M., 145 De Cock, J., 8 I Deepak, A., I 1 Deer. W. A., 164 Degens, E. T., 97 De Grazia, A. R., 147 Dehnen, W., 59 Dehove, B., 65 Deijill, E., 221 de Iongh, J., 232 de Jonge, J., 18 Dekate, Y. G ., 122 Dekhkankhodzhayeva, S. Kh., 121 Dekock, P. C., 161 Delany, A. C., 33 Delas, J., 122, 138 Delavault, R. E., 151, 153, 190 Delespaul, I., 29 de Lint, M. M., 188 Delly, J. G., 13 Delmas, A.-B., 95 Delmas, R., 36 Delobel, R., 89 De Luca, H. F., 84 Delumyea, R., 57 Delwiche, C. C., 104 Demuynck, M., 30,4 1 De Nee, P. B., 13 de Nevers, N., 62 Denison, P. J., 46, 56 Dennis, R., 2

A uthor Index de Pena, R. G.. 12 De Pierro. J . N., 62 Dergunov, I . D., 20 I de Rijck. T.. 29 Desaedeleer, G., 48 de Sequeira, E. M., 109, 125, 141, 158 Detroy, R. W., 230 Deul, M.. 196 Devi, S. S., 100 de Vries, M. P. C., 142 De Wiest, F., 25 Dickens, F., 2 I2,22 1 Dickens, J. W., 2 18 Dickson, A., 248 Dickson, J., 80 Diem, H., 5R Diener, U . L., 220 Dietz, F. D.. 154 Dietz, T. M., 64 Dillon, P. J., 54 Dimler, R. J., 232 Dinman, B. D.. 150 DiPasquale, L. C., 58 Dittberner, G. J., 47, 65 Dixon, E. J., 80 Dixon. J . B., 108, 131, 159, 163, 164, 165. 175 Doan, M. H., 62 Dobbs, J . E., 200 Dobrazanski, B., 103, 1 12, 124, 127. 130, 135, 137, 158 Doisy, R. J., 79, 9 1 Dolezalek, H., 3 Dollear, F. G., 23 I , 233 Dolobovskaya, A. S., 170 Dolphin, G. W., YO Domergue, J. L., 35 Doner, H. E., 163 Doran, J. W., 193 Dorn, C. R., 6 1 Dorsett, R. S., 6 I Doskey, P. V., 57 Doucet, S., 120 Doxtader. K. G.. 148 Doyle, L. J., 37 Doyle, P., 120 Drake, M. J., 114 Draxler, R. R., 46 Drees, L. R., 165 Drew, J. V., 142 Drozdova, T. Z., 120, 198 Drummond, D., 236 Drury, J . S., 79 Dryburgh, F., 72 Dubief, J., 44 Dubikovskii, G. P., 192 Dubreuil, A., 59 Duce, R. A., 6, 8. 18, 28, 33, 34,48, 56, 193, 235, 249 Dudas, M. J., 152 Dudley, H. C., 87 Dudley, R. F., 154 Duff, R. B., 163 Duggan, M. J., 198

27 1 Dugger, W . M., 157 Duhameau. W., 30 Duinkcr, J . C.. 265 Dumon. J . C.. 109 Duncan, L. J., 62 Dunn, H. W., 12 Du Rant. J . A.. 23 1 Durston, W. E.. 2 12 Dutton, J. W. R., 254 Duven, D. M., 8 1 Dvorackova, I., 2 15 Dwivedi, K . N.. 137, 141 Dyabin, Y . P., 24 Dybek, I. J.. 196 Dybzynski, R., I7 Dyrssen, D., 15 I , 240 Dzieciolowski, W., 121, 127, 137, 141, 157 Dzubay. T. G., 9, 16 Eaker, D., 224 East, C., 62 Eaton, A., 250 Eaton, F. M., 184 Eaton, J . S.. 52 Eatough, D. J.. 38 Eatough, N. L., 38 Ebens, R. J.. 17 1 Eckert, J . A., 1 1 Edmond, J. M., 236, 238, 243. 244, 249,259.260 Edmonds, J. S., 88 Edson, R., 48 Edwards, H . W., 25 Edwards, M. A., 206 Egan, A. R., 122, 128, 132 Eggleton, A. E. J., 28, 42 Ehmann, W. D., 150 Ehrlich, R., 59 Ehrnebo, M., 90 Eichorn, G. L., 58 Einarsson, E. H., I8 1 Eisenbud, M., 40,44, 52 Eisman, J.. 84 Ekelund, S., 13 Ekstrand, J., 90 El-Damanty, A. H., 127 Elder, F. C., 56 Eldred, R. A., 64 Elfimova, E. V., 58 Elfving, D. C., 146 Elgroth, M. W., 53 Elinder, C. G., 80 Eliott, E. R., 35 Elling, F., 2 16 Elliot, J . S., 80 Elliott, H. L., 72 Elliott, W. P., 46 Ellis, B. G., 125, 190 Ellis, H. T.. 34 Ellis, K. J.. 84 Ellis, W . H., 81 Ellison, G.. 14 Ellison, J . McK.. 59 Ellison, R. K., 27

El Shami, S., 79 El-Sissy, L., 137. 138 Elsokkary, I. H., 14 I Elsom. D. M.. 30 Elzerman. A. W., 57 Ernelyanova. M. P., 198 Emerson, S . , 246 Emery. J. F., 12, 36 Endoh, T.. 53 Engel, R. E., 19 1 Enger, L., 49 England, G.. 2 England, J., 66 Enwezor, W. O., 177 Epov, I. N., 149 Eppley, R. M., 216. 232 Epstein, S., 145 Erametsa. O., 1 18 Erchul, L. D., 203 Erdman. J . A.. 14. 171 Erdody. P.. 80 Erkins. J . H.. 6 Erlank, A. J., 1 1 1 Erne, K., 154 Ervio. R., 17 1 Escher, F. E., 233 Eskenazy, G. M., 16 1 Eskilsson, C., 13 Evans, C. A., jun.. 12, 37 Evans, D.. 54 Evans, G. W.. 85 Evans, H. T., jun., 113 Evans, R. B.. I I Fagbami. A . A.. 141 Failey. M . P., 16 Fairbridge, R. W., 120. 178 Falk. H. L.. 57 Fan, K. C., 5 Fang, C. L., 106, 107, 109, 112. 121. 124, 127, 133, 135, 137, 141, 157, 168. 169 Farlow, N. H., 22 Farmer, J. G., 186 Farmer, V. C., 159 Farrow, M.. 80 Fasching, J. L., 6. 28, 34. 48 Fassett, D. W., 145 Fea, G.. I2 Feder. W. A.. 13 Fedorov. E. A.. 200 Fegley, R. W., 34 Feklichev, V . G.. 150 Feldman. C.. 36 Feldstein. M., Y Fell. G. S., 72. 80 Fenn, R. W., 29 Fennell. D. I., 220 Fenters. J.. 59 Ferguson. T. L., 148 Fernald. F. G.. 1 1 . 47 Fernandez. R.. 59 Fernandez. T. C.. 135 Ferris. B. G.. 62 Ferry, G. V.. 22

Author Index

272 Fersmana, A. E., 116 Feth. J . H., 97 Feucht, M., 80 Feuell. A. J., 232 Feve, J. R., 89 Fevraleva, L. T., 200 Fiedler, H. J., 94 Fiefenbach, B.. 144 Fields. T., 8 1 Finn, B. J., 172 Fisher, B. E. A,, 46 Fisher. D. A.. 8 1 Fisher, E. M. R., 7, 3 1 Fisher, G. L., 12. 37 Fisher, J. W., 38 Fisher, M. J., 38 Fitzgerald. J . W., 9 Fitzgerald, R. A.. 250 Fitzgerald, W . F., 28, 69, 250, 25 1 Fitzpatrick, R. W., 109 Fleischer, M.. 114, 145, 147, 181, 182 Fleming, G. A., 94, 193 Fleming, R. A., 46, 56 Fleming, R . W.. 193 Fletcher, I. S., 34 Fletcher. W. K., 120, I9 I Fletcher, W . W., 85 Flocchini. R. G., 64 Flohn, H.. 65 Florence, T. M.. 238,240, 265 Florkin, M., 100 Fogg, T. R., 69 Follett, E. A. C., 159 Follett, R. H.. 94 Follis, R. F., 90 Folsom, T. R., 235 Foltz, C. M., 194 Fondu. M., 79 Fontan, J., 47 Fontanges. R.. 58 Forbes, E. A., 138 Ford, D., 59 Fordtran, J., 84 Fordyce, J . S.. 5, 4 1 Foreback, C. C.. 72, 24 I Forgacs, J., 205 Forland, E. J., 53 Forrest, J.. 4 1 Forsius, P. 1.. 8 I Foss, J . E., 116 Foster, J. M., I72 Foster, N. D., 96 Fotakieva, E.. 12 1 Foussain, A.. 19 Fox, I).G., 46 Fox, T. D.. 2 1 Francesconi, K . A.. 88 Francis, B. J.. 232 Franco. J., 79. 80 Frank, H. K., 222,232 Frank, R., 124, 127, 130, 133. 135. 137, 141, 144, 155, 169. 189

Frank, W. M., 67 Franz, A. 0..233 Franz, H., 59 Franzin, W. G., 53 Fraser, R. S., 44 Fredriksson, L., I90 Frei, R. W., 86 Freie. R. L., 218 Freney. J. R., 177, 178 Frey. F. A.. 115 Friberg. L., 58, 145 Friedlander, S. K., 3, 25, 39,41, 51 Friedman, M. H., 7 1 Friedrichs, K. H., 60 Frigieri, P., 29 Frissel, M. J., 152, 178 Froelich, P. N., 238 Frohlich, C., 10 Froude, F. A.. I 1 Frush, C. L.. 47 Fryer, B. J., 146 Fuchs, N. A., 3 Fuentes, T. F., 100 Fukuta, N., 8 Fulkerson, J . F., 2 18 Fulkerson, W., 36, 145, 150 Fuller, W. H., 22 Furr, A. K., 146 Fymat. A. L., 9 Gaarenstroom, P. D., 41 Gabovich, R. D., 79 Gagner, C., 250 Galba, J., 189 Gallagher, J. C., 84 Gallego, R., 187 Calvin, P. J., 53 Gamble, D. S., 151, 159 Gamboa, J. J., 100 Gandrud, B. W., 22 Ganguly, A. K., 8 1 Gangwar, M. S., 141 Ganje, T. J., 145, 170 Ganjir, B. L., 141 Ganor, E., 44 Gant, V. A., 8 1 Garber, R., 5 Garcia, S. R., 2 1 Garcia-Miragaya, J., 144 Card, J. A., 159 Gardiner, H. K., 233 Gardiner, M. R., 194 Gardner. D., 250, 265 Gardner, D. E., 59 Garland. J . A., 33, 50 Garland, T. R., 201 Garner, R. J., 205 Carrels, R. M., 1 I3 Gatti, R. C.. 15 Gatz, D. F., 40. 41. 52 Gaudry, A., 20 Gauntner, D. J., 22 Cause, E. M.. 60 Geering, H. G., 192

Gent, C. A., 19 1 Gent, M., 62 Gentry, J., 5 George, P., 80 Georgiadi, G. A., 58 Georgu, H. W., 2,47 Gerasimova, M. I., 113 Gether, J., 12 Ghanem. 1.. 137, 138 Gibb, J., 10 Gibb, T. R. P., 250 Gibbs, 0. S., 8 1 Gibson, E. J., 103 Gibson. F. W., 64 Gibson, R. D., 6 Gieseking, J. E.. 165, 174, 176, 178 Gilbert, E. N., 148 Gilbert, T. R., 242 Gildersleeves, P. B., 66 Gile, P. L.. 190 Giles, J. B., 95, 112 Gill, A. C . , 201 Gill, G. A., 28 Gill, R., 15 Gillard, R. D., 93 Gillespie, F. C., 71 Gillette, D. A., 32, 33, 64 Gilmour, J. T., 155 Gilpin, L., 182 Girneno, A., 2 16 Gins, J. D., 3 1 Giordano. P. M.. 125, 138, 142. 145, 146 Girin, P. Yu., 116 Girling, C. A., 149 Gissel-Nielsen, G., 192, 193 Gitter, M., 222 Gittins, M. J., 62 Givand, S. H., 88 Gizyn, W., 37 Gjessing, Y. T., 53 Gladney, E. S., 36,41, 113, 198 Glancy, E. M., 209,22 1 Glinski, J., 103, 106, 107, 112, 124, 127, 130, 135, 137, 158 Goddard, J., 256 Goeller, H. E., 145 Gohda, S . , 24 1, 252 Goldberg, E. D., 48, 115. 238, 240,264 Goldblatt, L. A., 206, 231, 232 Goldschmidt. V. M., 1 10. 170 Goldstein, H. L., 37 Goldstein, 1. F.. 30 Goldwater, L. J.. 85 Golikov, 0. P.. 199 Gomez. J., 80 Gong, H., 143 Gonzales, T. W.. 12 Goodman, B. A,, 113. 128, 130, 138 Goodman, G. T., 14.47, 172 Goodman, H. S., 29 Goranson. S. K., 40

Author Index Gorbacheva, A. Ye., 12 1 Gorbanov, S. P., 122 Gordeev, V . V., 256 Gordon. D. C., jun., 250 Gordon. G . E.. 16, 38, 41. 113 Gordon, S. A., 166 Gorham, E.. 54 Gorlach, E., 122 Gorman, R. C.. 194 Gormican, A., 79 197 Gorski, M.. Gotoh, S., 128, 152 Gottfried, D., 147 Gough, L. P., 14, 39 Goulding, F. S., 15 Grace, C. I., 85 Gracey, H. I., 152 Graf. J. L., jun., 1 15 Graham, G . G., 83 Graham, L., 8 1 Grams, G. W., 2 1,65 Granat, L., 30 Grant, A. B.. 194 Grant, B., 236 Grant, V. E., 1 1 5 Gras, J . L., 4 Grasserbauer. M., 12 Gratz, D. F., 30 Grauby, A., 200 Grauer, N. M., 8 1 Gravatt, C . C., 6 Gravenhorst, G., 20 Graveson. R. T., 6 Gray, W. M., 67 Graybeal, L., 4 Greeberg, J. P., 22 Greenberg, R. R., 38 Greenkorn, R. A., 49 Greenland, D. J., 163, 165 Gregers-Hansen, B., I93 Grewal, J . S., 122 Grienert, H., 14 1 Griffin, T. B., 59 Griffing, M . E., 40 Griffiths, N . M., 80 Grigorev, G . I., 197 Grigor’yeva, T. A., 187 Grim, S. 0..85 Grimaldi, F. S., I13 Grimaud, D.. 253 Grimme, H., 133, 138 Gringel, W.. 44 Grodovsky, M . , 122 Grodzinska. K., 14 Grosjean. D., 25, 28 Grove, J. H., 125 Grover, S. N., 53 Groves, M. J., 7 Gruender, H . D., 5Y. 6 I Grunewald. T., 232 Grzybowskya, D.. 32 Gubler, C . J.. 81 Guderran, R.. h I Guencau, L., 79 Guerin, I., 25

273 Gurson, C. T., 8 1 Guillier, A., 88 Gupta, G. P., 141 Gupta, I. C., 98 Gupta, R. D., 103 Gupta, U. C., 157 Gurskii, G . V., 198 Gusev, M. I., 58 Gutenmann, W. H., 146 Guthrie, B. E.. 79. 80, 9 1 Guzman, L., 19 Gyrd-Hansen, N.. 2 16 Gyul’akhmedov, A. N., 157 Haag, T., 8 0 Haas, T., 8 0 Haatz, J. C., 16 Hackney, J. D., 59 Haga, Y., 79 Hagedorn-Gotz, H., 93 Hagen, L. J., 32 Haghiri, F., 144, 145, 200 Haik, M., 6 Hake, R. D., 1 I Hald, B., 223 Hales. J. M., 52 Hall, J. L., 38 Hall, M . L., 8 0 Hall, R., 184 Hallgren, D. S., 4 Hallsworth, E. G., 132 Halm, B. J., 176 Halsey, V. S., 80 Halstead, R. L., 172, 176, 177 Hamaguchi, H., 146 Hambidge, K . M., 8 I Hamdi, H., 127 Hamdy, A. A., 19 I Hamielec, A. E., 53 Hamilton, E. I., 79, 8 0 Hamilton, J. C., 98, 101 Hamilton, L. D., 63 Hamilton, P. B., 2 18 Hamm, J . W., 155 Hammerle, R. H., 5 Hammock, R. D., 220 Hammock, L. G., 220 Hammond, P.. 145 Hammond, T., 137 Hammons. A . S., 79 Hamstra, A., 84 Hanawelt, R . B., 17 1 Handreck, K . A.. 165 Hanel, G., 26 Hanko, E., 154 Hanna. S. R., 67 Hansen, A . D. A., I6 Hansen. L. D., 38 Hansen, R. O., 1Y7 Hanway, J . J . , I77 Hao, W . M.. 249 Hapke. H . J., 5Y, 173 Hara, T.. I90 Harder, H.. 156 Hardin, L. J.. 18 I

Harker, A. B.. 28 Harland, B. F., 79 Harp, M. J., 8 0 Harries, J . M., 70 Harrington, J. M., 70 Harrington, J . S., 58 Harris, W. F., 49 Harrison, G . E., 80, 8 4 Harrison, H., 27 Harrison, J . L., 182 Harrison, R. M., 25, 39, 60, 171 H a r r i s , R. C., 148 Harshvardhan, 65 Hartley, T. F., 89 Hartley, W. J., 194 Harvey, B. R., 254 Harward, M. E., 116 Harwig, J., 2 18 Haschek. W. A., 146 Hashimoto, Y., 193 Haskin, L. A., 115, 116, 118, 147 Hassan, M. N., 137, 138 Hasse, L., 52 Hasselager, E., 223 Hassett, J . J., 144, 172 Hatch, M . B., 190 Hatcher, B. W., 181, 189 Hauck, R. D., 174 Haulet, R., 35 H a m , C . C., 58 Haunold, E., 155 Havas, M.. 37, 54 Havlova, J., 5 Hawkes. H. E., 194 Hawksworth, D. L., 13 Hayes, A. W., 212,213,215 Hayes, D. M., 22 Hayes, M . H. B., 163, 165 Hayman, D. S.. 176 Heard, M . J., 39, 60, 87 Heathcote, J . G., 206 Heddle, J . A., 25 Heffron, C. L., 146 Heffter, J . L., 34 Hegg, D. A., 35 Heidorn. K. C.. 45 Heidt, L. E., 12 Heier, K. S., 96, 196 Heindryckx. R., 23 Heinonen. R., 2 15 Heinrich, K . F. J., 6 Heinrichs, H.. 143, 170 Heintpenberg, J., 64 Helmke, P. A.. 105, 107, 117, 119, 124, 127, 130, 133, 141, 142, 197, 198 Hellstriim, G.. 8 1 Hem, J . D., 126, 151, 169 Hemenway. C. L., 4 Hemphill. D. D., 37, 138. 171, 172. 193 Henderson. G . S.. 49 Henkin, R . I . , 8 I Henmi. T.. 48

Author Index Hensley. W. K., 198 Hepple, P., 172 Herbert, C. N., 181 Herman. B. M., 65 Herpetz. E., 3 Herrero, J. 1.. 94, 12 I , 127. 130, 137 Herrington, J., 8 0 Herrmann. A . G., 115 Herrmann, R., 203 Herron, M. M., 53 Hertzberg, M., 4 Hesketh, H. E., 2 Hess, R. E., 190 Hesseltine, C. W., 206, 212, 220,223,224.230.23 1 Heurtebise, M.. 8 I Heuss, J. M.. 46 Hewson. E. W., 4 1 Hey, R. D.. 30 Heydemann. A., 138 Hiatt, V., 49 Hibbert, J. R.. 206 Hibbs. S., 3 Hicks, R. B., 45, 50. 51, 52 Hidalgo. H.. 64 Hidy, G. M., 22. 2 7 , 4 1 Higashi, T.. 94 Hildebrand. E. E.. 170 Hill. C. H.. 72 Hill. M. W.. 38 Hill. S. T., 206 Hill, W. W., I22 Hiltbold. A. E.. 190 Himes. F. L., 200 Hindman. E. E.. 9. 39, 67 Hinesly, T. D.. 145, 152 Hinkley. T.. 97 Hinsall. R. D.. 2 I8 Hinton, J . W., 81 Hislop, J. S.. 16 Hitchcock. A . E., 152 Hitchcock, D. R.. 49 Hites, R. A,. 25 Hluchan, E., 190 Hobbs, P. V.. 34, 35. 39. 53, 66, 67 Hochrainer. D., 4 Hocking, D., 38 Hodge, V . F., 238 Hodgson. J. F.. 133 Hoed. F.. 138 Hoekstra. W. G.. 178 Hoenig, V., 8 I Hoff. R. M.. 1 I Hoffer. E. M.. 17, 27 Hoffman, D.. 25 Hoffman, E. J., 33, 34, 235 Hoffman, R . S.. 17 Hoffmann. D. J.. 4 , 3 4 Hoffmann, G. L.. 18.56 Hofstra. G.. 184 Hogan. A . W.. 18.20.52 Hogan. G. R.. 2 15 Hoggan. M. C., 3 1

Hogstrom. U., 49 Holdeman. J. D., 22 Holden, J. M., 79 Holdgate, M. W.. 57 Holford. T. R.. 64 Holm, E., 201 Holmes, A., 59 Holmes. P. L., 171 Holobrady. K., 189, 190 Holtzman, R. B., 60, 79 Holzapfel, C. W., 230 Honeysett, J. L., 132, 133, 142 Hood, R. D.. 2 12 Hoover, W. L., 189 Hopke, P. K., 41 Hopkins, T. L., 37 Hoppe. H.-J.. 108 Hopper, M. J.. 172 Horak. O., 12 1 Horiguchi, S., 79 Horner. E. S.. 23 I Hornvedt, R.. 184 Horst, T. W., 33 Horovitz, C. T., 199 Horovitz-Kisimova. L. A.. 199 Horton, J. H., 61 Horvath, D. J.. 71, 128 Horwitz, W., 218 Hostalek, Z., 208 Hoste. J.. 79 Hounam, R., 57 Housworth. J.. 70 Hovmand, M. F., 14, 32. 42. 61, 98, 103, 105, 127. 130, 133. 135, 137, 141, 144, 169 Howard, E. A., 46 Howard, J. H.. 195 Howard, P. A., 189 Howie. R. A., 164 Hsieh, D. P. H., 224, 230 Hsu, J. M., 7 1. 9 1 Hsu. P. H., 15Y Huang, T. C . , 35 Huber. F.. 88 Hubert, A. E., 148. 149 Hudson, J. G.. 9 Hudson, R. D., 2 1 Huebert, B. J.. 12 Huey, C. L.. 85 Huff, J. E.. 49 Hughes, R. C., 8 0 Hulett, L. D., 12, 36 Huljev. D.. 15 1 Hume, D. N., 242 Hume, R.. 4 1 Hurnenik. F. M.. 22 Hundemann. P. T., 145 Hunt. B. G., 47 Hunt. C. D.. 250. 25 1 Hunt. D. C.. 209 Hunt. I. F., 8 0 Hunt, R. D.. 46 Hunt. W. F., jun.. 62 Huntzicker. J. J.. 17. 39 Hurley. P. M.. 96

Hursh, J. B., 86, 87 Hurtung, R., 150 Husar. J. D., 17 Husar. R. B., 2. 9, 17. 23, 51. 63 Hussein. F. E. R.. 8 0 Hutchinson. D. H.. 4 I Hutchinson, E.. 199 Hutchinson, T. C., 37, 48, 54, 72,240 Hutton, J. T., 108 Hutzinger, 0..86 Hwang. J. Y., 193 Hydes, D. J., 237 Hyldgaard. J., 216 Hyun, Y., 5 Ichikawa, M., 8 0 Imamura, Y.. 8 0 Inarida, M.. 80 Ingerson. E.. 19 I Inhaber, H.. 30, 3 1 Inoue, K.. 152 Inoue, M.. 188 Inskip, M. J., 14 lokhel’son, S. V., 99, 200 lotov, M., 199 Ireland. F. E., 6 1 Ireland, P.. 84 Irlweck, K., 8 1 Isbels, L. S., 8 1 Ishekawa, M., 200 Ishida, K., 124. 127. 130. 133, 135. 137, 141, 144. 155, 169, 189 Ishizaka, Y., 21 Ishizaki, M., 7Y Iskandar, I. K . , 155 Isoard, P., 58 Isohata, E.. 2 16 Isono, K., 21 Itasaka. M.. 53 Ivanov, L. A., 120 Ivanova, E.. 15 1 Iverson, W. P., 85 Iwai. I., 190 lwasaka, Y., 1 1 Iwata, S., 8 I lyengar, G. V., 79 Izawa. M., 28 Jacko, R. B.. 37. 38 Jackson. D. R., 6 I Jackson. M. L.. 32, 109. 142 Jackson. S., 9 0 Jacob. K . D.. 188 Jacobs. L. W.. 155. 189, 190 Jacoby. B., 142 Jaeger. H., I 1 Jaenicke, R., 26. 44 Jaffre, T., 125. 135 Jaffe. W . (3..80 Jagner. D.. 15 I Jahnke, R. A.. 24 1

275

Author Index Jaklevic, J. M., 15 James, P. E., 154 Janssens, M., 30 Jarvis, S. G., 139, 144, 146, 172 Jeans, C. V., I16 Jeffries, D. F., 56, 254 Jeffries, D. S., 54 Jellema, J. U., 9 4 Jenik, M., 190 Jenkins, C. E., 56 Jenkinson, D. S., 164 Jenne, E. A., 128, 150,249 Jennet, J. C., 172 Jennings, S. G., 27 Jernelov, A., 153 Jervis, R. E.. 26, 119, 144, 161 Joensen, A. W., 38 Joenssuu, 0. I., 79, 154 Joffe, A. Z., 2 13 Johansson, A., 59 Johansson, G., 15 Johansson, T. B., 15,2 I , 193 John, M. K., 141, 144, 145, 152, 169 John, W., 4 Johnsen, I., 14 Johnson, A. H., 182 Johnson, C. M., 172 Johnson, D. B., 26 Johnson, D. E., 79 Johnson, D. L., 153,240,241 Johnson, H. L., 79 Johnson, L. R., 44, 1 YO Johnson, S. A., 27 Johnson, S. P., 6 I Johnston, A. E., 198 Johnston, S. E., 19 1 Jonasson, 1. R., 53, 150, 151, 152 Joncich, A., 46 Jones, A . G., 41, 113 Jones, B. D., 2 18 Jones, B. M. R.. 28 Jones, C. M., I Jones, D., 159 Jones, D. G., 63 Jones, G. B., 192, 250 Jones, H. E. H., 2 12, 22 1 Jones, J. B., 103 Jones, J. S., 189, 190 Jones, L. H. P., 139, 144, 146, 165, 172, 177, 192 Jones, M. M., 250 Jones, R. L., 145, 152, 182. 183 Jones, R. S., 147 Joplin, G. A., 96 Jorden, R. M., 36 Jori, H., 80 Josefsson, B. G. E., 2 16 Joseph, K. T., 79 Joshi, M . S., 170 Joshi, P. V., 25 Jost, D., 3 I Juchnowski, T. A., 62 Judah, D. J., 227,229

Judeikis, H. S., 27 Junge, C., 21,47 Jungreis, C., 128 Junkerman, W., 27 Juo, A. S. R., 106 Juran, C., 122 Jurinak, J. J., 144 Jurney, E. T., 36 Juste, C., 122 Kaakinen, J. W., 36 Kaden, D. A., 25 Kadis, S., 206, 2 13 Kadowaki, S.. 27.44 Kaila, A,, 99 Kaiser, H.. 6 1 Kaistha, B. P., 103 Kakuto, Y., 142 Kalb, G. W., 36 Kalbasi, M., 141, 142 Kalhorn, S., 57 Kalmar, E., 200 Kalpage, F. S. C. P., 122 Kamprath, E. J., I03 Kanabrocki, E. L., 8 1 Kanisawa, M., 2 12 Kaplan, E., 8 1 Kaprou, M.. 40 Karaban, T. T., 187 Karim, H., 128, 138, 142 Karvonen, M. J., 8 0 Kary, R. E., 3 Kasai, A., 195 Kato, M., 200 Kato, T., 220 Katsumo, Y., 150 Katz, J. L., 22 Katz, M., 15, 17, 25 Kaufmann, P. E., 8 7 Kaw, J. L., 59 Kawabata, Y., 230 Kawasaki, H., 152 Kawase, K., 200 Kearney, P. C., 190, 191 Keddie, A. W . C.. 4 1 Keeney, D. R., 189, 190, 19 1 Keilen, K., 101 Keith, M. L., 97 Keitz, E. L., 62 Kelkar, D. N., 25, 29 Kelliher, D. J., 173 Kellogg, W. W., 64 Kelly, J. M., 49, 54 Kelsay, J. L., 79, 8 1 Kelso, W. I., I13 Kemp, K., 15 Kennedy, C. D., 8 1 Kennedy, D. R., 155 Kenny, N. C., 8 1 Kent, G. S.. I I Kent, N. L., 8 1 Kerin, Z., 172 Kerr, S. A., 16 Kerrich, R., 146 Kerrigan, G. C., 39

Kershaw, G. F., 122 Keschamaras, N., 2 I5 Kester, D. R., 25 I , 257 Keusch, F., 59 Keyl, A. C., 233 Khare, I., 79 Kharkhar, D. P., 146 Khitrov, L. M., 116 Kiang, C. S., 47 Kiehland, J. T., 7 Kiermeier, F., 223. 232 Kiessling, K.-H., 230 Killick, C. M., 29 Killough, G. G., 6 3 Kilmer, V . J., 100 Kilpatrick, B. E., 125 Kim, C. K., 81 Kim, N. B., 79 Kimble, J. M., 125 Kimura, K., 125 Kimura, Y.. 152 King, R. B., 5, 4 1 King, W . D., 2 1 Kinkel, A. R., 149 Kinkead, E. R.. 58 Kirchoff, V. W. J. H., 1 1 Kirkham, M. B., 145 Kirkpatrick, D. C.. 80 Kisel, T. 1.. 127 Kishk, F. M., 137, 138 Kitzinger, A., 149 Kjellstrom., T., 79, 80, 145 Klappenbach, E. W., 40 Klee, J., 17 I Klein, D. H., 36, 153 Kleinman, M. T., 8, 40.44, 52 Klevay, L. M., 79,80 Klimovich, P. V., 94 Kline, J. R., 116 Klinkhammer, G. P., 253, 254. 256 Kloosterman, B. L., I55 Knaeuer. G. A., 246, 249, 254 Kneip, T. J., 8,40, 52 Knox, G. E., 116 Knutson, E. O., 53 KO, M. K. W., 7 Kobiashvili, V . I., 112 Kochetkova, T. A., 58 Kocialkowski, Z., 12 I , 1 2 7. 137, 141, 157 Kociba, R. J., 59 Kodaira, M., 200 Kodama, H., 164 Koehler, P. E., 233 Koenig, W., 190 Koeppe, D. E.. 144. 172 Koga, H., 152 Koide, M., 114, 115 Kojima, S., 79 Kolb, H., 62 Kollmer, W . E., 79 Kolomiitseva, M. G.. 79 Koltun, S. P., 233 Konishi, S., 250

Author Index

276 Konrad, Z., 238,240,265 Koons, R. D., 105, 107, 117, 119. 124, 127, 130, 133, 141, 142, 197, 198 Kopp, F., 11 Koretz, R. L., 93 Koritnig, S., 18 1 Korkman, J., 177 Koshy, A., 2 15 Kosta, L., 80, 8 1 Kothny, E. L., 17, 27, 113, 149, 150, 157, 194 Koval’skii, V. V., 122, 199 Kowal, N. E., 79 Kowalczyk, G. S., 4 1 Kownacka, L., 32 Koyumidjisky, H., 128 Kozlowski, T. T., 6 1 Kozyreva, M. G., 200 Kraemer, D. F.. 79 Kramer, C. J. M., 265 Kramer, L., 79, 80, 85 Krause, G. H. M., 5 9 , 6 I Krauskopf, K. B., 142 Kremling, K., 246, 265 Krempp, G., 97 Krenkel, P. A., 150, 172 Kretzschmar, J. C., 9, 29 Kreutzer. K., 184 Krishnamachri, K. A. V. R., 215 Krishnamurthy, L.. 2 15 Krishnan, S., 25 Krog, H.. 14 Krough, P., 2 15, 2 16, 223, 224 Kruger, J., 9 Kruglova, V. G., 191 Kruglova, Ye. K., 12 1 Krupskiy, N . K., 127 Kruse, E., 198 Ku, T. L., 235, 236 Kubasik, N . P., 8 1 Kubota, J., 122, 193 Kubota, S., 53 Kuchar, P., 38 Kudinov, Yu. A,, 116 Kuhl, G. L., 79 Kumai, M., 53 Kumplainen, J .. 8 1 Kunaskeva, K. G.. 197, 199 Kuppers, G., 93 Kurbanayev, M. S., 162 Kurihara, T., 79 Kurki, M., 142, 202 Kuroda, P., 146 Kurono, T., 79 Kusak, V., 2 15 Kuzina, F. D., 154 Kvatek. M., 191 Kvetnaya, 0. M., 200 Kwoka. M.. 59 Kwolek. W. F., 2 18. 23 1 Laaksovirta, K., 13, 14 Labanauskas, C. K.. 139

Lacey, J., 206 LBg, J., 154, 171, 183, 189 La Fleur, P. D., 6 Lagerwerff, J. V., 145, 154, 171 Laird, A. R., 46 Lakanen, E., 17 1 Lakin, H. W., 148, 149, 194, 195 Lal, D., 52, 235 Lal, F., 127, 130, 137, 141, 157 Lamb, B. K., 46 Lamberg, B. A., 8 1 Lambert, G., 20 Lambert, M. S., 196 Lamoreaux. R. J., 144, 145 Lamothe, P. J., 9 Landa, E. R., 151, 153 Landergren, S., 198 Landing, W. M., 254 Landis, D. A., 28 Landowitz, L., 30 Landsberg, H., 3 Lange, B. A., 16 Langer, G., 5, 53 Langford, J. C., 56 Langham, W. H., 9 1 Langsford, J. B., 88 Langville, W. M., 137 Langway, C. C., jun., 53 Lantin, R. S., 232 Lantzy, R. J., 4 8 La Prade, J. C., 23 1 Laresgoiti, A., 4 0 Largin, 1. F., 203 Larsen, A. E., 2 16, 223 Larsen, S., 175, 182 Larson, T. V., 26, 27 Laruelle, J.. 94 Latimer, D. A,, 63 Laul, J. C., 37 Law, D. V., 3 I Lawasani, M. H., 36 Lawson, D. R., 29 Laxen, D. P. H., 25. 171 Lazar, V. A., 122 Lazrus, A. L., 12.22 Leaderer, B. P., 64 Leaf, A. L., 190 Leahy, D., 5 Leaseburge, C.. 5 Leatherland, T. M.. 250 Lebedev. V . N., 192 Le Bouffant, L., 59 Lechler, P. J., 98. 99, 103, 105, 106, 107, 109, 112, 117, 124, 196 Lee, C., 79 Lee, D. E.. 8 0 Lee, D. H. K . . 12 Lee, H. L., 2 12 Lee. I. C., 79 Lee. J., 125. 135 Lee. L. S.. 232,233 Lee, R.. 100. 103 Lee, R. E.. jun., 37

Lee, Y.W., 154 Leeper, G. W., 122 Leidner, L., 27 Legotte, P. A., 8 0 Lehnert, G., 8 0 Leininger, R. K.. 98, 99, 103, 105, 106, 107, 109, 112, 117, 124, 196 Leistner. L., 223 Lem, H. Y., 22 Lenihan, J. M. A., 7 1, 85 Lentschig, S.. 94 Leong, B. K. J.. 59 Lepel, E. A., 34 Lepple, F., 44 Le Riche, H. H., 102, 106. 108, I33 Lerman, L., 6 1 Le Roux, J., 109 Leslie, D. M.. 128 Lesure, F. G., 149 Leuschner, A. H., 9 Leutwein, F., 192 Levaggi, D. A., 9 Levander, 0. A., 80, 89 Levesque, M., 94 Levett, G., 2 18 Levick, R., 127. 133. 137. 141, 169 Levi-Minzi, R., 145 Levin. Z.. 27 Levine, R. A., 79 Levri, E. A,, 8 I Levy, A., 39 Levy, D., 62 Lewis, C. W., 9 Leyden, D. E., 237 Li, Y. H., 235 Liang, Y.-J., 257 Liebig, G. F.. 16 1 Lillehoj, E. B., 218, 220, 221, 230, 23 1,232 Lilliard, D. A., 232 Lima, P. H., 6 1 Lindberg, J. D., 27 Lindberg, P., 194 Lindberg, S. E., 49 Lindsay, W . L., 94. 125, 138, 141, 142, 175 Lindstrom, R. M., 16 Ling, C. S., 17 Likens, G. E., 52 Linn, W. S., 59 Linnman, T., 8 0 Linsell, C. A., 215 Linton, R. W.. 12, 37 Lippmann, M., 8. 57, 59 Lisk, D. J.. 101, 146 Lisowe, R. W., 59 Liss, P. S., 34. 52, 237. 246 Littfass, M.. 1 1 Little. P.. 39. 50. 60. 87. 145 Litton. C. D.. 4 Liu, B. Y. H., 5 Liu, M. K., 46

Author Index Lockyer, D. R., 177 Lodge, J. P., 3, 5 , 13 Loetzsch, R.. 223 Loh, A., 37 Long, D. T., 240 Longwell, J . , 79 Loo, B. W., 15 Loos, A. C., 4 0 Lorenzen, A., 46 Lorius, C., 53 Lorusso, L., 188 Louis, J. F., 47 Lough, W. F., 8 I Lounamaa, J., 110, 124. 147 Loveland, W . D., 4 1 Lovering, J. F., 150 Lowder, W . M., 196 Lowe. L. E., 177 Lowenthal, D. H., 242 Lu. J . C. S., 240 Lucas, M. D., 109, 141, 158 Lucas. R. E., 202 Luckey, T. D., 72 Ludwick. J. D., 2 I Ludwig, F. L., 4 1 Lumis, G. P., 184 Lund, T., 1 1 Lundborg, M., 59 Lunde, G., 12 Lundgren. D. A., 25 Lusis, M. A., 27 Lutz, A., 53 Lyles, L., 32 Lynch, J. J., 150 Lynn, W. C., 163 Lyon, T. D. B., 8 0 Lyon, W. S.. 12, 36, 150 Lyons. W. B.. 25 1 McCaffrey, R. J., 29, 32 McCance, R. A., 8 I McCartney, E. J.. 10 McCartney. M. J.. 250 McCormick. M. P.. 22 McCrone, W. C.. 13 McDonald, A. J., 195 MacDougal, J. D., 148 Macdougall, A. I., 72 McDuff, R. E., 243 MacEachern, C . R., 141. 190 McElroy, M. B.. 20 McFarland, A . R., 8, 37 McFarlane, G. A., 53 McFarlane, J. C., 153 McFee, W. W.. 49, 54 McGaveston, D. A,, 198 McGeown, M. G.. 8 1 McGerrigle. J. 1.. 149 McGovern, B.. 58 McGrath, P. P., 13 McGuckin. M. A., 80 McHardy. W. J.. 159. 162 McHenry. J. R., 201 Machta, L.. 45 Macias, D. F.. I4 I

277 Macias. E. S., 9 Macias, F. D., 137 Mclnnes, G., 19 Maclntire. W. H . . 181 Mclntyre, A. D., 58. 85, 86 Mackay. D.. 38 McKeague, J. A., 103. 105, 106, 109, 124. 127. 130. 133. 135, 137. 141. 155, 158, 159, 169, 189. 193 McKee, D. E., 40 McKellison, J., 5 Mackenzie, F. T., 48,237 Mackenzie. R. C., 159 McKenzie, R. M.. 121, 127, 128, 132. 133, 137. 141, 170 McKercher, R. B., 176 McKinlay, K. S., 86 McLachlan, R. D., 176. 178 McLaren, A . D., I76 McLaren, R. G., 138 McLaughlin, R. J. W., 147 MacLean, A. J., 153, 154, 172 McLean. E. 0.. 158 MacLean, K. S., 137 McLean, R. 0.. 104 Macleod, K . E., 37 McMahon, T. A., 46 McMeans, J. L., 220 McNeal, J. M., 15 I McNeely, M. D., 8 1 McNesby, J. R., 8 McPhee, A. W., 190 MacPhee, R. D., 5 Madsen, A,, 2 16,223 Makitie, O., 133, 135 Maenhaut, W., 1, 17 Magee. R. A.. 37 Magno, P. J., 87 Magono, C., 53 Mahaffey, K. R., 79 Mahaney, W. C.. 159 Maher, C . T., 2 I Maheswaran. P.. 16 Mahler, R. J.. 145 Maiwald, K., 19 1 Maksimovic, A., 1 16 Maksimovic. Z., 116 Malaby, K. L.. 14 Maleksakhin. R., 200 Malissa, H., 12. 15 Malkovich, P. Sh., 200 Malmqvist, K., 15 Maker, J. L., 79 Mamane, Y., I2 Mamuro, T., 26, 200 Manami, K., 141 Manes, A., 3 1 Mangano, J . J., 3 1 Mangelson. N. F., 38 Mangum, B. J., 244 Manley, T. R., 182 Mann, G. E.. 233 Mann, L. K.. 39 Mann. R. M.. 37

Manning, D. C., 150 Manowitz. B., 2 2 , 4 1 Manskaya, S. M.. 120, 198 Manton, M. J., 5 Manton. W. I.. 6 0 Mantoura, R. F. C., 248 Manwiller, A., 23 1 Marchesani, V . J., 62 Marenco, A., 47 Margolin, M., 133, 137, 141, 185, 187. 189 Marienfeld, C. J., 17 1 Marier, J . R., 79 Markali. J.. 12 Markina, N. A.. 58 Markovic, N., 12 1 Markowitz. H., 8 1 Marks, R. H., 172 Marlow, W., 5 Marple, V. A.. 9 Mart, L., 265 Martens, P. H., 138 Martin, A.. 54 Martin, A. E., 70 Martin, J.-C., 59 Martin, J. H., 246. 249, 254 Martin, M. H., 15, 145 Martin, P. G., 79 Martin, R. E.. 35 Marusyak, V. D., 24 Masek, V., 6 1 Mason, H. S., 100 Massart. D. L., 8 1 Massey, H. F., 139 Masui, J . , 137. 141 Matharu, H. S., 250 Mathe, J . F., 89 Mathews, T., 45 Mathieu, G. G., 235 Mathur, M. M., 2 I5 Mathur. P. D., 2 I5 Matoush, L. 0.. 8 0 Matson, W. R.. 154 Matsuhisa, T.. 79 Matsumoto, H., 167 Matsunaga. K.. 250 Matsunami. T., 26 Matthews. K. M., 200 Mattingly. G. E. G.. I98 Maughan, R. A.. 41 Maurice, J.. 94. I56 May. K. R., 3 Mayeda, T. K.. 32 Mayer, R.. 54, I70 Maxia. V.. 79 Measures, C. I.. 242. 243. 244 Medaris, L. G., 116 Meelu, 0. P.. 196 Meggitt. W. F., 19 I Megie. G.. 1 I Meglen. R. R., 80 Megumi. K.. 200 Mehlman. M. A,, 212.220.223. 224.23 1 Mehta, B. V., 193

278 Meinel, A. B., 34 Meinel, M. P., 34 Meinke, W . W., 81 Meisenheirner, R. G.. 38 Meldau, R., 159 Melke, J., 106, 107, 112, 124. 127, 135, 137 Mellanby, K., 6 Melnick, D., 233 Meloni, S., 79 Melstead, S. W., 103 Melton, J. R., 189 Meltzer, L. E., 8 0 Melville, G. E., 177 Meranger, J. C., 79 Mercer, C. J., 4 Merefield, J. R., 190 Meret, S., 8 1 Merriman, R. J., I16 Merry, R. H., 17 I Mertz, W., 79, 8 0 Meserole, F. B., 37 Meszaros, E., 21, 26 Metson, A. J., 103, 177, 178 Meyer, D. R., 125 Meyer, F. K., 125 Meyer, J. H., 9 3 Meyers, R., 5 Michaelson, E. D.. 59 Michard, G., 253 Michas, C., 224 Michel, R. G., 8 0 Middaugh, J. P., 70 Miera, jun., F. R., 201 Miettinen, J. K . , 85 Migdisov, A. A., 115, 1 16 Mikac-Devic, M., 8 1 Mikhailov, V. A., 148 Miksad, R. W., 46 Mikulin, R. G., 201 Miles, J. R., 190 Miles, M. K., 66 Miller, B. J., 128, 138 Miller, D. F., 39 Miller, D. S., 83 Miller, E. B., 8 1 Miller, E. C.. 229 Miller, F. J., 59 Miller, F. L., 39 Miller, H. G., 7 Miller, J. A., 229 Miller, J. D., 7 Miller, J. E., 172 Miller, J. M., 30, 34 Miller, J. O., 144 Miller, R., 97 Miller, R. W., 152 Miller, V. L., 152 Millman, A. P., 167 Mills, C. F., 58, 85 Mills, G. L., 265 Mills, J . C., 124, 153 Millward, G . E., 15 1 Milne, D. B.. 79, 9 0 Milnes, A. R., 108

Author Index Minami, K., 137 Mincheva, E., I6 I Minor, M. M., 198 Minski, M. J., 79, 80, 149 Mirabel, P.. 22 Mirchev, S., 12 1 Mirocha, C. J., 209, 213, 218, 2 20 Mirumyants, S . 0.. 24 Mishra, B., 127 Misra, K. C., 122 Misra, S. G., 122, 189, 193 Mitchell, B. D., 159 Mitchell, H. H., 84 Mitchell, J. G., I16 Mitchell, J. R.. 80 Mitchell, R. L., 94, 98, 99, 100, 103, 105, 106, 107, 109, 112, 116, 121, 131. 133. 161, 168, 202 Mitchell, T. J., 58 Mitchell, W. A., 165 Mitman, F. W., 81 Mitsui, S., 166 Mixon, A. C., 23 1 Miyake, Y., 242,258,263 Mizuno, H., 145 Mizuno, N., 125 Moav, B., 8 1 Msller, T., 2 16 Moller, T. E., 2 16 , Moeschlin, S., 72 Moffat, J., 171 Moghadissi, M. A., 8 Moghissi, A. A., 153 Mokler, B. V., 8 Mokwunye, A. U., 103 Molloy, L. F., 130, 158 Molyneux, M. K., 4 Mondragon, M. C., 8 0 Monson, P. R., 46 Monteith, J. L., 50 Moon, W. H., 79 Moore, M. R., 87 Moore, R. M., 260, 26 1 Morehouse, L. G., 206, 220, 223 Moreira-Nordemann, L. M., 198 Morgan, A., 57,59 Morgan, J. J . , 240 Morgareide, K., 209 Morimoto, S . , 28 Morita, K., 59 Moriyama, S., 65 Morozova, N. G., 197 Morris, A. W., 252 Morris, D. F. C., 148 Morris, R. J., 250 Morris, R. V., 114 Morris, S. C., 6 3 Morris, V. C., 8 0 Morrison, G. H., 149 Morse, D. L.. 70 Mortensen, H. P., 2 16, 223

Mortvedt, J. J., 125, 138, 142, 145 Moser, B. C., 4 Mosi, A. D., I2 1 Moss, J., 54 Mossbaek, H.. 6 I Motina, A. G., 166 Motto, C. K., 171 Motto, H. L., 171 Motuzova, G. V., 157 Mouvier, G., 25 Moyers, J. L.. 4 1 Mroz, E. J., 34, 35 Mudd, J . B., 6 1 Mueller, E.. 190 Muhleisen, R., 44 Mukherji, P., 25 I Mundie, C. M., 128, 138 Munkelwitz, H. R., 22 Munn, J. I., 8 7 Munn, R. E.. 4 5 , 6 4 Munnich, K. O., 52 Murad. E., 118 Murata, K. J., 1 1 7 Murphy, J . V., 85 Murphy, N. J., 8 0 Murphy, T. J., 57 Murr, L. E., 12 Murray, J. W., 252, 256 Murthy, G. K., 79 Murthy, P. S., 12 Muskett, C. J., 39 Muth, 0. H., 194, 195 Mutscher, H., 100 Muysson, J. R., 162 Myron, D. R., 80, 88 Nadeau, M. H., 7 9 , 8 0 Nadeau, S., 38 Nadkarni, R. A., 149 Nagamoto, C . T., 53 Nagarajan, V., 2 15 Nagpal, K . K., 199 Nagpal, M. K., 199 Nagy, K., 16 Naidenov, M., 107, 1 17, 119, I56 Naidenov, T., 100, 124 Nair, K . P. P., 94 Nakao, M., 79 Nakuda, K., 80 Nalovic, L., 95 Naoi, M., 230 Nason, A. P., 79 Nathani, G. P., 100, 137, 141 Natusch, D. F. S., 12, 37 Navarre, J. L., 44 Navrot, J., 127, 130, 133, 137, 141, 142, 157, 185, 187, 189 Nayyar, V. K., 145 Neal, G. E., 227, 229 Neale, G. J., 194 Nechay, M. W., 8 1 Neefus, J. D., 8 I

2 79

A u t ho r Index Neenan. M.. 122 Nees, R. T.. 10‘ Neher. R. E.. 20 1 Neidzwiecki. E.. 14 I Nelson. J. W., 15. 30 Nelson. R . A.. 8 0 Nemetschek. Th.. 59 Nemetschek-Gansler. H., 59 Nesdinol, P. 2 15 Nesheim, S., 2 16 Netterville, D. D. T., 45 Nettesheim. P.. 58 Neuendorf. D. W.. 37,38 Neuerberg, G. J., 149 Neuman. W . P., 86 Neustadter, H. E., 5, 4 1 Nevitt, J. S.. 3 1 Newham, J., 14 Newhouse. M., 62 Newman, A. C. D., 165 Newman, L., 5 , 16.4 1 Newton. D., 60, 84 Newton, G . J., 8 Nguyen, B. C., 20 Nicholas, D. J. D.. 122. 128. 132, 195 Nicholson. A. J.. 178 Nickless, G.. 15 Nielsen, F. H.. 80. 88. 93 Nielson, K. K.. 37 Nikolaev. D. S.. 196 Nilsson, K. O., 144. 154 Ninemiya, K.,79 Nisbet, 1. C. T., 145 Nishikawa, Y.. 252 Nishimura, M.. 250 Nodiya, P. I., 79 Noel, R., 30 Noller. B. N., 29 Nomoto, S., 8 1 Nordberg, G. F.. 58,60, 145 Norman, J. C., 118 Norred, W. P. 233 Norris, C., 85 Norrish, K., 128, I33 North, D. W . . 68 Novakov, T.. 16 Nozaki, T., 80. 186 Nriagu, J. O., 48,49, 173, 174 Nurnberg, H. W., 265 Nullens, H., 15 Nunnelley, L. L., 8 1 Nutter, D. E., jun., 152 Nyhan. J. W., 201 Nyland, T. W.. 8 Oberding, D. G., 40 Oberg. S. G.. 58 Oberleas. D., 70 O’Brien, B. J., 200 Obrusnik, I.. 29 Obukhov, A. I.. 95 O’Connor, B. H., 39 O’Connor. R., 193

Oddie. T. H.. 8 1 Odum. W. E.. I7 I Oertel, A. C.. 95 Oester. Y . T.. 8 I Ogle. J. C.. 36 Ohnishi. Y.. 59 Ohno. S.. 80. 8 I Ojea. F. G.. 135. 141. 142 Okamura. T.. 79 Okita, T.. 28 Olafsson. J.. 250 Olausson. E.. 235 Oldfield. J. E.. 194 Oliver. R. C.. 66 Oliver. S . , 187 Olkkonen. H.. 13. 14 Olney, C. E.. 193 Olsen. M., 230 Olson. K.. 171 Olson, 0. E., 79. 125. 193 O‘Moore. L. B.. 122 Omueti. J . A. I.. 182. 183 Ondov, J . M.. 9.36. 37 Ong. H. L., 149 Ophaug, R. H.. 79 Opiela. H . , 13 Orabi, A. A., 127 Ord. W. O., 232 Ore, C.. 80 Orel, A. E., 28 Orlando. P.. 79, 80 Orr, J . S . , 7 1 Osborne, V. E.. 152 Osgood, J . W., 220 Osiname, 0.A.. 142 Osis, D.. 80. 85 Osmond. J. K.. 196 Ostadalova, I., 72 Osterroht. C., 265 O’Toole, J. J.. 14 Ott. W. R.. 62 Ottoway. J . M., 80 Ouellette, G . J.. 122 Ovchenkov, V . Ya., 200 Overley, F. L., 190 Overstreet, R., 20 1 Owst, A. P., 6 Oxbow. A., 17 I Ozek, F., 16 Ozerova, N. A.. 15 I Paciga, J. J., 26 Packham, D. R., 35 Padmanabhamurty, B., 44 Page, A. L.. 143, 145. 170 Page, B. J., 39 Pahren, H. R., 79 Pakarinen, P., 203 Paliwal. K. V., 9 1 Palmer, 1. S., 79 Palmer, W. T., 145 Panday, V. K., 79 Panin, M. S., I38 Papay. L. T., 63 Pareek, B. L.. 99

Parfenov. Y . D., 90 Parizek. J.. 72 Parker. G. R., 49 Parker. R. D.. 9 Parker. W. A.. 233 Parkinson. T. F.. 146 Parmenter. F. C.. 10 Parry. G. D. R.. 14 Parson. J. W.. I74 Parsons. G. E.. 8 I Parsons. R.. 264 Parungo. F. P.. 12.67 Parryck, D. C.. 63 Pashneva. G. E.. 197 Pashutin. V . P.. 150 Pasquill. F.. 46 Pasternack. B. S.. 4 0 Patel, C. A.. 193 Patel. C. K . N.. 1 1 Paterson. M. P.. 34 Pathre. S. V., 2 13. 220 Patriarche. G. J.. 8 I Patsukevich. Z. V.. I13 Pattenden. N. J.. 3. 19 Patterson. C. C.. 56. 238 Patterson, D. E.. 23 Patterson. D. S. P.. 209, 213. 2 16. 2 19. 220. 22 I . 222. 223. 224.227.229 Patterson, E. M.. 64 Patterson. R. K.. 64 Patterson, T. A.. 237 Patwardhan. V. N., 79 Paul. E. A. 176 Paul. S. K.. 67 Paulev. P. E., 85 Paull. R. E.. 172 Paulsch, W. E.. 22 I Paulus. H. J.. 25 Pavanasasivam. V.. 122 Pawley, J . B.. 12 Pawluk. S.. 152 Pearce. A. T.. 39 Pearman. G . 1.. 29 Pearson, K. H., 8 I Pedro. G.. 95 Peech, M.. I33 Peeler. J . T.. 79 Peers. F. G., 2 15, 224 Peirson, D. H.. 23. 47 Penkett. S . A., 28 Pensionerova. V . M.. 19 I Pepin, T. J., 4 Perdelli. F.. 79. 80 Perevalov. M . 1.. 99 Perevezentsev. V . M.. 187 Perez, D.. 59 Perhac. K.. 42 Peristianis. G. C.. 2 16 Pernell, H. C., 59 Perone, S. P., 4 I Perry. E. F.. 80 Perry. H . M.. 80 Perry. R., 39 Pershagen. G.. 8 0

Author Index

280 Persson. B. R. R., 201 Petel. R. L.. 57 Peters. L. K.. 52 Petersen. H.. 246 Petersen. K., 128 Petersen. 0. K.. 2 16 Peterson. G. H., 176 Peterson, M. L., 24 I Peterson. P. J.. 122, 125. 149 Peterson. R. E.. 220. 232 Pettersson, H.. 230 Peysakhov. Ya. M.. 157 Pfannenstiel. R. J.. 62 Pfannhauser. W.. 7Y Phillips. M.. 5 Phillips. P. E., 6 1 Philp. L. A.. 209 Phipps, G. L.. 6 1 Picer. M.. 8 I Pierce. J . 0..61. 171 Pierrou. U.. 176 Pierson. W . R.. 5.40 Pietig. F.. 198. 200 Pietrini-Pallotta. A.. 79, 8 0 Pilotte. J . 0..30 Pilson. M . E. Q.. 240. 242 Pinchin. M. J.. 14 Pinchuk. M.. 30 Pinnick. R. G.. 9 Pinta. M.. 95. I61 Piotrowicr.. S. R., 34. I93 Piotrowska. M.. 182 Piotrowska. N.. 121 Piperno. E.. 60 Piscator. M.. 145 Pitz. N.. 59 Plambeck. J . A.. 38 Platou. J.. 177 Pleban, K . H.. 81 Pliler, R., 196 Plotnikov. V. I.. I92 Pobequin. Th.. I I6 Poddubnyi. N . N.. 99 Podporina. Y . K ., I I6 Poelstra. H. S.. 28 Poelstra. P.. 152 Pohland. A.. 218. 228. 232 Polemio, M.. I88 Polley. H.. 59 Pollock. J. B.. 65.66 Polson. C. J.. 83 Polzer. W. H., 97 Pomeroy. N. P.. 3 Pons. W. A.. 232,233 Ponton, R.. 220 Poole. D. B. R.. 173 Popov. L. N.. 58 Pories. W. J.. 7 1 Porstendorfer. J., 5 1 Posner, A. M.. 138 Pott. F.. 60 Potzl. K.. 19 Prahrn. L. P., 46 Prasad. A . S., 70. 7 I Prasad. K . G., 98, 157. 182

Rao. A. K.. 8 Raridon. R. J.. 63 Rasmussen. L.. 13, 14 Raspor B.. 265 Rastogi. R. C.. 199 Raston. C. L., 88 Ratcliffe. J. M., 14 Raut, S. J.. 79 Ravikovitch, S., 127. 130. 133. 137, 141. 142, 157. 185. 187. 189 Ravnskov, U.. 2 16 Ray, B. J.. 34. 193 Raymond, W. H. A.. 80 Rayner. E. T.. 233 Rayner. J . H.. 164. 165 Razin. L. V.. 149 Reaves. G. A.. 109, 170 Reay. P. F.. 88 Rebbert. R. E.. 25 Rechnitz. G. A., 8 I Reck. S. J.. 79 Reddy. R. S.. 17 1 Reed. E. 1.. 2 1 Reeves, R. D.. 125. 135. 171 Rehfus. R., 150 Rehm, G. W.. I77 Reid, J., 23 1 Reid, J . T., 146 Reid, L. M., 57 Reid. R., 54 Reiners. R. S.. 150 Reiners. W. A.. 172 Reinhart. M.. 59 Reischl. G.. 5 Reiss. N . M .. 3 1 Reiter. E. R.. 48 Quarles, H. D., 111. 17 I Reiter. R.. 3. 1 1 . 19 Quin. B. F.. 122. 123 Reith, J. W. S.. 133. 138 Quinn. J. G.. 193. 265 Renovanr. H. D.. 59 Quirk. J. P.. I38 Reuss, J. 0.. 54 Reuther, W.. 139 Raabe, 0. G.. 8 Rabinoff. R., 65 Reynoldo. E. F.. 230 Rhea. U., 79 Rack. E. P.. 8 1 Ribeiro, M. E.. 8 0 Racz, G. J.. 141. 142 Ricci. P.. 30 Radke, L. F.. 34. 35. 39. 53. 66 Rice. C. M.. 101 Rae, T., 58 Rice, H. B.. 103 Raffke. W.. 79 Rice, W. L.. 149 Ragaini. R. C.. 8. 36. 37. 38 Rich. C. I., 97 Ragg, J. M.. I39 Richards. L. W .. 28 Rahill. R. L.. 98 Rahman. Q.. 59 Richardson. K. A,. 196 Rahn, K. A., 6. 8. 23, 29. 30. Ridley. W. P.. 72 Rieke. P. E.. 190 32.33 Rahola. T.. 85 Riffaldi. R., 145 Raikov, L., 199 Riggs. B. L.. 84 Rakshit. A . K.. 79 Riley. A. E.. 37 Ralston. H. R.. 38 Riley. J. P.. 34. 234. 235. 248. Ramachandra Murty, A. S.. 67 250 Rarnalingaswarni. V.. 2 15 Risby. T. H.. I7 Rampy. L. W., 59 Ritchie, J . C.. 201 Rancitelli. L. A., 37 Ritter. C . J.. 154 Randhawa. N . S.. 122. 196 Roaldset. E.. 1 15. 1 I7 Rankin. P. C.. I I7 Robak. H., 181 Rantu. R., 79 Robbins. C. W.. 193

Prather. E. S.. 79. 8 1 Pratt. P. F.. 103. 121. 127. 1.30. 1.33. 135. 137, 141. 158 Prentice. B. A.. 37 Presant. E. W.. 128 Preston. A., 254 Price. J . E.. 2 15 Priemskaya. A. E.. 202. 203 Priest. P., 44 Prigge. E., 173 Prince. A . L.. 103. 109. 112, 168, I69 Prinz. B.. 14 Prister. B. S.. 187 Probert. M . E., 178 Proctor. D. F.. 5 7 Proctor. J.. I25 Prodi. F.. 10. 12 Prokhorov. V. M., 200 Prosky. L.. 79 Prospero. J. M.. 10. 20 Protasova, N. A., 122 Proulx, H., I 2 Proulx, R. A.. 67 Provenanzo. G.. 32 Pruppacher. H. R.. 53 Pueschel, R.. 12. 37. 67 Pui, D. H. Y.. 39 Punsar. S.. 8 0 Purchase, 1. F. H., 206. 213. 2 15.22 I . 223.230 Purdy, W. C., 8 1 Purushottam. D., 198 Purves. D.. 61, 139. 143 Pyle. J. L.. 220

Author Index Roberds, D. W., 9 Roberts, B. A., 39, 209, 216, 2 19.220.22 I . 222.223 Roberts. E., 17 1 Roberts. G. H.. 4 1 Roberts, H. R., 23 1 Roberts. L. H., 39 Roberts, L. J., 145 Roberts. N.. 38 Roberts, P. T., 64 Roberts, T. M., 172 Robertson. C. E.. 97 Robertson, D. E.. 24 1 Robertson. J.. 79. 8 0 Robertson, K. J., 250 Robertson, R. A., 202 Robig. G.. 5 1 Robins, A. G . . 45 Robinson, G . D., 64 Robinson, M. F.. 8 0 Robinson, W. O., 117. 18 I Robson, A., 6 0 Robson, L. E., 15 Robtsov. D. M., 197 Rodhe, H., 47 Rodricks, J. V., 206. 212, 216, 220.222,223.224,23 1 Roedel, W., 27 Roesler. H. J., 190 Rogers, C. F., 9 Rogers. J. J. W., 196 Rogers, R. D.. 49. 153 Rogge, H. D., 59 Rohm, K. J., 8 1 Rohwer. P. S.. 63 Rolfe, G. L.. 61, 172 Rollier, M. A., 79 Romano. D. J., 3 Romanov, G. N., 200 Romney. E. M.. 102 Ronaghy. H . A.. 7 1 Ronneau, C.. 44 Ronov, A. B.. 1 1 1 . 115, 116. 120 Root, D. B.. 36 Rosa. W . C., 8 0 Rose, A. W.. 143. 15 1 Rose, D.. 79 Rose. F.. 13 Rose. H. J.. 8 1 Rose. W. I.. 12 Rosen. H., 16 Rosen. J. M.. 4, 34 Rosenberger, G., 59. 6 1 Rosenfeld. I.. 70. 194 Rosenvold. R. J.. 25 Rosinski. J.. 5. 53 Roslyakova. N . A.. 149 Roslyakova. N. V., 149 Rosopulo. A.. I7 I Ross. G. J.. 159 Ross. W. J.. 8 I Rossi, L. C., 79 Rossner. H.. 108 Rostgaard, M., 2 16

28 1 Roszyk, E.. 125, 129 Roth, P., 84 Rothbaum, H. P.. 198 Routh, M. W.. 8 1 Rowe, J. J.. 147 Rowe, M. D., 6 3 Roy, B. R., 8 I Roy, W. R.. 98, 99. 103, 105, 106. 107, 109, 1 12. 117, 124, 196 Rozhkov, 1. S., 149 Rubilin. E. V.. 200 Rubino, R . A., 6 1 Rubinson, A. C., I18 Rubow, K . L., 9 Rudeforth, C. C., 100, 106, 110, 117. 127. 130, 135, 137, 141, 185, 189 Ruebner, B. H., 224 Ruettner, J. R., 59 Ruf, H.. 100. 101 Ruffer, L.. 232 Rumberg, C. B., 191 Rump, H . H., 203 Rundo, J., 84 Rupp, E. M., 63 Ruppert, J.. 54 Russ, E. R., 250 Russell. E. W., 159, 164 Russell, J . C.. 59 Russell, J . D., 159 Russell, P. B., 1 I. 45 Rutman, J . , 8 Rutman. R.. 80 Ryan, N. J., 2 15 Ryan. P., 94 Ryder. J.. 38 Rylander, R., 59 Saas. A., 200 Sabey. B. R., 145 Sabroux, J. C., 35 Sackett, W. M.. 235 Sackner, M. A., 59 Sadasivan, S., 26 Sagan, C., 65,66 Saha, J . G., 86, 150. 154 St. Arnaud. R. J., 109, 144, 154. 183. 189 Sakanque. M.. 201 Sakurai, H.. 80 Salamone, M. F., 25 Salhab. A. S., 230 Salmon, L., 7, 16, 31. 201 Salmon. R. C.. 102 Sal’nikov. V . G.. 187 Saltzman. B. E.. 8 1 Sarnsahl. K.. 8 0 Sandberg, D. V.. 35 Sandberg. J. S., 9 Sander, S. P.. 27 Sanders. W.. 150 Saner, G., 8 I Santaroni. G.. 79 Santillan Medrano. J.. 144

Santoprete, G.. 74, Santroch, J., 29 Sapek, A., 127, 133. 135, 137, 141, 169 Sapetti, C., I7 1 Sarofin, A. F., 145 Sartorius, R., 3 1 Sasajima, K., 8 1 Sasuga, T., 8 0 Saukov, A. A,, 15 I Saunders, W. B., 83, 86 Savoie. D. L., 10 Saxena, S. N., 157, 176 Saxena, V. K., 8.67 Scales, J. T.. 8 0 Schaller, K. H., 80, 8 1 Scharpenseel, H. W., 198, 200 Schaule, B., 56. 238 Scheff, P. A.. 9 Scheider, W. A., 54 Schelenz, R., 79 Schelz, J . P., 16 Schiller, P., 149 Schindler, J. E., 152 Schlesinger. R. B., 59 Schlipkoter. H. W.. 59, 60 Schmidt, U., 88 Schmitt, R. A.. 115 Schnakenberg, D. D., 79 Schneider. C. J., 71 Schneider, S. H., 64 Schnitzer, M., 164 Schock, H. H., 199 Schoenhard. G.. 190 Schofield, C. L., 54 Schrauzer, G. N.. 7 1 Schreck, R., 59 Schrocder, H. A., 72, 79. 80, 81,89 Schroll, E., 195 Schroll, J., 195 Schubert, J. R., 194 Schull, G.. 14 Schuller. P. L.. 2 18. 22 I Schulte, E. E., 142 Schultz, R. K., 150, 201 Schuhz-Dobrick, B., 143 Schumacher, P. M., 6 Schuster. B. G.. I I Schutz, A., 59 Schwartz. K.. 194 Schwartz. R., 79 Schwartz. S. E., 47 Schwarz. K . . 85, 90 Schwela. D. H., 52 Schwertmann, U.. 109 Schwitzgebel, K., 37 Sclarew, R. C.. 46 Sclater. F. R., 238. 249, 259 Scorer. R. S.. 34 Scott. N . M.. 178 Scott. P. M.. 218 Scott. R. 0.. 163 Scott. W. D., 34 Scoular. F. I.. 8 0

Author Index

282 Scriven. R. A,. 46 Segall. H . J.. 72 Searle, P. L.. 108 Seaward. M . R. D.. 13 Sedberry. J . E., jun., 128, 138. 142 Sedlak. M.. I90 Sehmel, G. A.. 52. 56 Seidel, S. L.. 238 Seils. C., 57 Seinfeld. J . H.. 27. 28 Selezneva, E. S., 17 Selikoff, 1. J.. 12 Sell, J. L., 154 Selvam. A. M.. 67 Semb. A., 54 Semenov. E. I., 150 Sensi. M.. 188 Sequeira. R.. 29 Sequi, P.. 122 Serebrennikov. V. V.. 197 Serkies. J . J.. 62 Servant, J.. 36. 5 1 Seth.S. P.. 100. 137, 141 Sethuraman. S., 3 1 Settle. D., 56 Severson, R . C.. 39 Shabynin. L. L., 149 Shacklette. H. T.. 98. 101. I 11, 118. 145. 148, 149 Shadoan. D. J.. 64 Shair, F. H., 46 Shakuri, B. K., 98. 106, 112, 124. 135 Shales, S. W.. 145 Shand, C. A.. 155 Shani, G.. 33 Shank, R. C.. 2 15 Shanker. H., 137, 141 Shanks, H. R.. 38 Shannon, G. M.. 22 I Sharma B. M.. 137. 141 Sharma. 0. P., 127 Sharma, P. K.. 103 Sharova, A. S.. I22 Shaw. D. M.. 3 5 . 161. 162 Shaw. D. T.. 7 Shaw. G. E.. 1 9 , 3 3 , 3 4 Shaw. T. L.. 15 Shchukin, A. B., 200 Sheesley, D. C.. 5 Sheih. C. M.. 45 Shepherd Burton, C., 46 Sherman, G. D.. 108 Shewry, P. R.. 125 Shibuya. M.. 185. 186 Shigematsu. 1.. 79 Shigematsu, T.. 252 Shils, M . E., 84 Shimizu, M.. 8 0 Shimmins. J., 7 1 Shimoishi, Y.. 243, 244 Shinde, D. A.. 127 Shleien. B.. 8 7 Shoji. S.. 137. 141

Short, N. M.. 105 Shotwell, 0. L.. 2 18. 22 1 Shreeve. B. J.. 209, 213, 220. 222,223 Shrift, A.. 194 Shrimp, N.. 103, I 12, I24 Shukla, U. C.. 08. 182 Shuler, T. R., 8 0 Shults. W. D.. 60, 150 Shum. Y. S.. 4 I Sibley, T. H., 240 Sidelnikova, V . D., 191 Sidhu. S. S.. 39 Sidik, S. M.. 5 Siefferman, G.. 198 Siegel, B. Z., 154 Siegel, S. M.. 154 Siegmund. C. W.. 37 Sievering. H.. 56 Silberman, D., 37 Sillanpaa, M., 202 Silverman, B. A.. 67 Silvola, J.. 14 Simonich, D. M., 1 I Simonsen. G. H.. 122 Sims, J. D.. 17 1 Sindeeva, N. D.. 19 1 Sine, H. E.. 8 I Singer, L.. 79 Singh, B., 122 Singh. D.. 14 1 Singh, J . J.. 38, 59 Singh, M., 127 Singh, S., I22 Singha, S. K., 98 Sinha, S. B.. 14 I Sinnhuber. R. 0..2 12 Sipos. L.,265 Skelton, B. W., 8 8 Skerfving, S.. 59 Skirrow, G., 34, 234 Sklavenitic, H.. 8 0 Sklodowski. P.. 127, 133. 135, 137, 141, 169 Sklyarov, G. A., 122 Skogerboe. R. K.. 16, 1 7 1 Sladkovic. R.. 19 Slater, T. F., 224 Slavina, T. P.. 197 Slingsby, D. R.. 135 Slinn. W. G. N., 26, 50, 52 Small, R. J.. 145 Smart, N. A., 154 Smierzchalska. K.. 201 Smith, B. H.. 122 Smith, D. B., 12 Smith, D. C., 79, 8 0 Smith. F. B., 46 Smith, F. F., 194 Smith. H., 79, 8 0 Smith, 1. C., 60. Y3. 148 Smith. J. C., 80 Smith. K . L.. 37 Smith. L. B., 79. 8 0 Smith. P. J.. 8 8

Smith. R. A.. 38 Smith. R. D.. 37 Smith, R. G., jun., 262 Smith, R. H., 115 Smith, S., 14 Smith, S. J., 184 Smith, T. B., 4 I Smith, W. H., 154 Smythe. W. R.. 8 1 Snetsinger, K . G., 22 Sneva, F. A.. 98 Snyder, D. S.. 54 Snyder. L. A.. 9 1 Snyder, W. S., 70 Sobecki. S.. 8 9 Soderlund, R., 174 Serndergaard, E.. 194 Sokolova. T. A., 157 Soldatini. G. F.. 145 Solgaard, P., 85 Sollman, T., 83 Soman, S. D., 79 Sommer, G.. 17 1 Sonoda, Y.. 190 Sood, S. K., 53 Soong, R.. 156 SpallholL, R. E.. 85 Specht. W. A., 171 Spector. W. S., 8 6 Speecke, A., 79 Spencer. D. W., 234.253.256 Spencer. H.. 79. 80, 85 Spicer. C. W.. 6. 28 Sporn. A.. 79 Spring. J . A.. 79 Springer. G. S.. 4 0 Spruit, D., 8 1 Spumy, K. R., 5 , 13 Spyrou. N. M.. 16 Srebrodol’skiy. B. 1.. 19 1 Sridhar, K., 32 Srivastava. U. S.. 79, 8 0 Stack, M., 2 16 Stahr, K . , 101 Stallard, R. F.. 236 Stampfer, J. F., jun., 42 Stanley, J. B., 232 Stanton, D. A.. 142 Stanton, R. E., 195 Starke. R., 192 Steele, A. K.. 254 Steen, B., 4. 6 Stefansson, K . M., 34 Steinnes. E., 14 Stelmach. Z., 185 Stenstrom, T.. 145 Stern. A. C., 2, 3, 57, 62 Stesney, J . A.. 194 Stevenson. F. J., 138, 174 Stevenson, I. L., 163, 174 Stewart, J . J., 182 Stewart. J . M.. 202 Stewart. J . W . B., 152, 155. 176. 177 Stewart. P. L.. 79. 8 0

Author Index Stewart, R. D. H.. 89 Stewart. T. B., 27 Steyn, P. S., 208. 230 Stiefel. T.. 58 Stiff. M. J., 83 Stiller-Winkler, R.. 59 Stirpe, F.. 227. 229 Stith, J. L., 34. 35 Stober. W., 13 Stockham, J . D.. 53 Stoeppler, M.. 93 Stoewsand, G. S., 146 Stoffyn, M., 237 Stoiber, R. E., 12 Stoilov. G., 94 Stokes, C. A., 67 Stokes, G. N., 6 1 Stolarski, R. S., 66 Stoloff. L., 215. 216. 218, 222, 223,230, 232 Stolwijk, J. A. J., 64 Stone, B., 153 Stoner, J., 250 Stoner, L. H., 246 Stoops, G., 94 Stopford, W., 85 Stott, A. N. B., 60 Stout, J. D., 200 Strain, W. H., 7 I Strand, J., 7 Strasser. P., 8 1 Street, J . J., 145 Streeten, D. H. P., 79 Streit, S., 8 1 Strickland, R. C., 144, 145 Strohal, P., 8 I , 15 1 Struempler, A. W.. 53 Stukel, J. J., 50 Stumm. W.. 65. 234, 264 Styles, J. A., 58 Suda, P., 124, 127, 130, 133, 135, 137, 141, 144. 155, 169, I89 Suder, J., 4 1 Sudom, M. D., 109 Suess, M. J., 28, 6 1 Sugden, T. M., I Sugimura, Y., 242, 258,263 Suhr. N. H., 143 Sullivan, E. M., 62 Summers, A., 66 Sumner, M . E., 19 1 Sundby, B., 250 Sundd, D. K., 189 Sunderman, F. W., 8 I , 93 Sung, T. C., 106, 107, 109, 112, 121, 124, 127, 133, 135, 137, 141, 157, 168, 169 Suomela, J., 87 Suschny, 0.. 17 Suttle, N. F., 122 Sutton, A,, 80 Sutton, D. C., 80 Suzuki, M., 8 1 Suzuki, S., 125, 2 12, 220

283 Suzuki, Y.. 242,258,263 Svanberg. S.. I 1 Svedung. I.. 49 Svensson, B. H.. 174 Sventikhovskaya, A. N., 203 Sverdrup. G. M., 9 Swaine, D. J.. 94, 106, 182 Swanson, V. E., 149 Sweeney, A.. 193 Swenson, D. H., 229 Swieboda, M., 61 Swift, R . S., 163 Swissler, T. J.. 22 Swoboda, A. R., 184 Syers. J. K., 155, 189 Syo, S., 167 Szadkowski, D., 8 1 Szalay, A., 113, 121 Szekely, A., 198 Szilagyi, M., 113. 120 Tabatabai, M. A., 177, 178 Taboadela, M. M., 135 Tackett, C. D., 4 Tag, P. M., 67 Tai. H., 155 Tait, J. M., 33. 159 Takahashi, E.. 167 Takahashi, K., 59 Takatoh, H., 166 Takeda, Y. E., 2 16 Takeyoshi. H., 59 Takitani, S., 220 Takkar, P. N., 130 Talati, N. R., 157 Talbot, R. J., 59 Talcot, R., 59 Talibudeen, O., I97 Talipov, R. M., 149 Talmi, Y., 36 Tammer, P. M., 188 Tampieri, F., 10 Tandon, B. N., 2 I5 Tandon, H. D., 2 15 Tandon, S. P.. 199 Tanner, J. T., 7 1 Tanner. R. L., 5 Tanno, M., 188 Tanskanen, H., 202 Tantashev, M . V., 24 Tardy, Y., 91 Tashiro, F., 230 Taskayev, A. I., 200 Tattersall, R. N., 83 Tatton, J. O’G., 79 Tauzin, J., 122 Taylor, D., 150 Taylor, F. E., 250 Taylor, F. G., jun.. 39 Taylor, J., 209 Taylor, J . A., 3 Taylor, R . M., 112 Taylor, S. R., 96, 101, 195 Tedrow, J . C. F.. 103, 112. 124

Tejning, S.. 154 Templeton, G. D., 111, 113 ten Brink. H. M., 28 Tensho. K.. 167 Teramoto. K.. 79 Ter Haar, G. I.. 40 Ternovskaya, 1. M., 187 Thacker, E.. 194 Thanukos, L. C.. 3 Thayer, J. S., 72 Theodore, L.. 2 Thilly. W. G., 25 Thom, G. C.. 62 Thomas, D. W., 89 Thomas, G. W., 184 Thomas. W. A., 118 Thomas, W . C., 8 1 Thomas, W . W., 39 Thompson, A.. 15 Thompson, I., 14 Thompson, L. K., 39 Thomson, C. D., 80,89 Thomson, 1.. 122 Thompson, J . G.. 181 Thompson, J. N., 80 Thorn, J., 80 Thornton, A. S., 62 Thornton, I., 120, 122, 171. 190, 191 Thurier, R.. 38 Tidball, R. R., 169 Tiffin, L. O., 125 Tikhomirov, F. A., 187 Tikhonov, S. A., 198 Tilak, T. B. G., 2 15 Tiller, K . G., 132, 133, 142, 145, 171 Tilling, R. I., 147 Tillman, C., 13 Timar, M., 59 Timonov, M. A., 58 Tinker, P. B., 97 Tinline, R. D., 154 Tinsley, J., 174 Tipton, I . H., 79, 80, 8 1 Tischendof, G., 19 I Tisue, T.. 57 Titaeva, N. A., 197, 198 Tiwari, R. C.. 189 Tjell, J . C., 61, 85, 98, 103, 105, 127, 130, 133, 135, 137, 141, 144, I69 Tkachuk, R., 154 TGei, K., 243, 244 Tokiwa, H., 59 Tokiwa. Y., 6 Tokudome, S., 152 Tolonen, K., 203 Tomasi, C., 10 Tomingas, R., 59 Tompkins, M. A., 72 Toon, 0. B., 65,66 Tooper, B. M., 22 Topping, G., 56 Toribara. T., 86

Author Index

284 Torjussen, W., 8 1 Tourtelot, E. B.. 13 1 Tragardh, C., 64 Trager, W., 232 Trauth, N., 97 Travesi, A.. 100. 107, 117, 119, 124, 156 Travis, J . R., 33 TrdliEka, Z., 19 I Tremearne, T. H., 188 Trip, L. J., 150 Tripathi, B. R.. 103, 127 Tripathi, N., 193 Trohlinger, J. D., 10 Trucco, R., 29 Trudinger, P. A., 176 True, M. B., 258 Truesdale, V. W., 244, 246 Truex, T. J.. 9 Trusty, G. L., 9 Tseng, W. P., 88 Tsongas, T.A.. 8 0 Tsuchiya, K., 8 0 Tsuji, T., 201 Tucker, A., 68 Tucker, J. H., 6 1 Tugarinov, A. I., 1 16 Tugsavul, A., 17 Tullett, M. T., 4 4 Turanskaya. N. V., I15 Turekian, K. K., 146. 191 Turner, A. C., 29 Turner, D. B.. 45 Turner, D. R., 240 Turner, W. B., 208 Turvey, D. E., 47 Tuzova. A. M., 1 1 I Twidale, C. R., 108 Twiss, S., 9 Twitty, B. L., 8 I Tyler, G., 172 Tyler, J. J., 145 Tyotina, N. A., I 13 Tyuremnov. S. N., 203 Uchida, H., 243 Uchiyama. M., 2 16 Udo. E. J., 14 1 Ueno, Y., 212. 218. 220, 224. 230 Ulrich, B., 54 Underwood. E. J.. 70. 106 Unwin, R. J.. 139 Uraguchi, K.. 206 Ure, A. M.. 98. 100, 101, 116. 118. 150, 155, 193 Urone. P., 80 Uthe. E. E., 42.45 Uziak, S.. 106, 107. 112, 124. 127, 135. 137 Vahter, M.. 145 Vainshtein. E. E., 1 I I Valadares. J. M. A. S.. 121. 139, 141

Valenta, P., 265 Vali, G., 67 Vallyathan, N. V.. 12 Van Camp, W., 66 van Cauwenberghe, K., 6 Vandeputte, M.. 8 1 Van der Klugt, N., 152 Vanderveen, J. E.. 79 van der Watt, K. J., 221 van de Vate. J . F., 28 Van Dijk, H.. 170 van Egmond, H. P., 221 Van Espen, P., 15 Van Eysinga, J. P. N. L. R., 186 Van Fassen, H. G., 153 van Grieken, R. E.. 21, 193 Van Hook, R. I., 36.49.60 Van Laerhoven, C. J., 145, 152 Van Loon, J. C., 54, 148, 154 Van Ormer. D. G., 81 van Rensburg. S. J.. 2 13 Vanselow, A. P.. 161 Van Valin, C . C., 67 Van Werden, K., 203 Vareille, J., 29 Varhelyi, G., 24 Vaswani, I., 84 Veillon, C.. 9 1 Venkata Rao, B. V., 142 Veno, F., 53 Venugopal, B., 72 Vercruysse, A., 8 I Veriovkin, G. V., 148 Verrett, M. J., 230 Vesela, J., 2 15 Vesely, D., 2 15 Vesonder, R. F., 232 Viezee, V., 1 1 Vijayakurnar, K..67 Vincent. L. C., 190 Vine. J. D.. 13 I Vinegar, A., 58 Vines, R. G., 35 Vinnikov, K . Ya., 65 Vinogradov, A. P., 10 1, 120 Viswanathan. P. N.. 59 Vitousek, P. M., I72 Vittal, K. P. R.. 141 Vittori. O., 52 Vlegaar, C. M., 29 Vlek, P. L. G.. 175 Vles, R. 0..232 Volchok. H. L., 6 Volosin, M. T., 8 1 Volz. F. E.. 34 von den Goltz. H.. 101 Vorotnitskaya. I. E.. I Y Y Vostal. J . J.. 85 Votava. H. J.. 85 Vouk. V. B.. 58 Vukovich. F. M.. 45 Wada, K.. 142. 159 Wadden. R . A.. 9 Wade. T. L., 193

Wadstrom. T., 224 Wadsworth, G. A., 54 Waggoner, A. P.. 26 Wagman. J., 64 Wagner, J . C., 59 Wagner, S. L., 8 0 Wahlberg. P., 8 1 Waiss, A. C., 232 Waiters, E. M., 250 Walker, B. S.. 8 1 Walker, T. R., 33 Wall, S. M., 6 WalLT., 198 Wallace, G. T., 34 Wallace, L., 4 Wallace, R. A., 150 Wallach. S., 84 Waller, N., 176 Waller, R. E., 59 Wallihan, E. F., 168 Walmsley, D., 100 Walravens, P. A., 80 Walsh, L. M., 190, 19 1 Walsh, P. R., 6, 8, 28, 34, 48, 63 Walsh, T.. 94, 122, 193 Walters. N. H., 87 Walters, W. B., 16 Walton, W. H., 58 Wang, P. K., 53 Wang, T. V., 227 Wangen, L. E., 8,36, 52 Wanner, A.. 59 Wanntorp, H., 154 Ward, D. E.. 35 Ward. F. N., 194 Ward, N. E., 17 1 Ward, N. I., 171 Warner, T. B.. 250 Warren, H. V.. 151. 153, 190 Waslenchuk, D. G., 24 I Waslien, C. I., 71, 79 Waterhouse, C., 86 Waters, M. D., 59 Watkins, J . L.. 29 Watkins, N . D.. 35 Watkinson, J. H., 80, 194 Watson. A. P.. 6 I Watt, J. J.. 98. 100, 101 Waynforth. H. B., 22 1 Weatherhead. A. V.. 108 Weatherley. M., 41 Weaver, C. E.. 196 Webb. J. S.. 120. 122. 191 Webber, G. R.. 94 Webber. J.. 54 Webley, D. M., 163 Wedborg. M.. 240 Wedding, J. B., 8. 50 Wedepohl. K. H., 96, 98, 99. 100. 101. 102. 104. 105, 107. 108. 110. 112, 113. 114. 115, 118. 119. 121. 122, 125. 130. 131. 134. 136, 139, 143, 146, 147. 150, 155, 158, 160, 161,

Author Index 162, 163. 164, 166, 167, 68, 173, 176, 179. 181, 185, 86, 188, 191. 194, 195, 196, 97, 203 Weed, S. B., 108. 159, 163. 64, 165. 175 Weed, S. O., 13 1 Wegelius, 0.. 81 Wehner, A. P., 59 Wei, E., 59 Wei, R.-D., 2 18. 232 Weickmann, H. K., 12, 67 Weimer, W. C., 56 Weinburg, E. D., 208 Weinig, E., 8 1 Weir, A., jun., 6 3 Weir, A. H., 106, 165 Weiss, G., 13 Weiss. H. V.. 53, 250 Weiss, R. F., 236, 256 Weissberg, B. G.. 153 Welford, G. A., 8 0 Wells, A. C., 60 Wells, B.. 29 Wells, N.. 94, 97. 98, 141, 156, 192 Welshman, S. G.. 8 1 Wenck, A., 265 Wenlock, R. W.. 80 Wentworth, R. A., 79 Werlefors, T., 13 Werner, C., 1 1 Werner, E., 84 Wesch, H., 59 Wesely, M . L.. 50, 5 1 Wesolowski, J. J . , 27. 4 1 Wessels, T. E., 14 West, R. E., 36 Wester, P. 0..79. 8 0 Westing, A. H., 184 Weswig, P., 8 0 Weyl, R., I08 Wheat, H. G.. 25 Wheeler. G. L.. 6 1 Whelpdale, D. M., 42.48, 64 Whitaker, T. B., 2 18 Whitby, K. T., 8, 9. 25, 26. 39, 41 White, A. H.. 88 White, A. J. R., 96 White, D. A,, 7 1 White, H. S., 80 White. J. A., 182 White, M . C., 145 White, W. H., 63. 64 Whitehead. D. C., 177. 188 Whitehead, E. I.. 193 Whitestone, R. R.. 189 Whitfield, B. L.. 63 Whitfield. M., 240. 264 Whitton. J . S., 97. 98. 141. 156 Wiacek, K.. I82 Wiatrowski. E.. 8 0 Widdowson. A. E.. 182 Widdowson, J. P., 100

285 Wideman, T. R., 115 Wiebe, H. A., 27 Wieczorek, G. A., 192 Wiendl, U., 120 Wiersma, G. B., 50. 155 Wiffen, R. D., 3.39.50.60 Wiklander, L., 154, 190 Wilcox, S. L., 62 Wild, A., 110 Wilder, B., 5 Wilding, L. P.. 165 Wildung, R. E.. 201 Wiley, M., 232 Wiley, M. L., 24 1 Wilk, G., 8 0 Wilkins, C., 100, 106. 110, 117. 127. 130, 135, 137, 141, 185, I89 Wilkinson, S. R.. 103 Willeke, K., 26 Willey. J. D., 238 Williams, A., 8 Williams, A. F.. I14 Williams, C., 122. 69. 177, 198 Williams, C. H., 144, 77, 178 Williams, D. R., 16 Williams, F. P., 4 1 Williams, K . T.. 189 Williams, M. L., 4 1 Williams, P., 12. 37 Williams. P. M.. 250 Williams, R. J. B., 102 Williams, R. J. P., 93 Williams. S. R.. 72 Williamson, R. H., 6 Willis, J . P.. 1 1 1 Wills, H., 59 Wilson. B. J.. 212, 213 Wilson. D. J., 45 Wilson, H., 86 Wilson, J., 58 Wilson, M., 8 0 Wilson, M. J., 109, 125, 159. 162 Wilson, W. E., jun., 39. 42 Wimmer. J . , 155 Winchester. J . W., 15. 19. 21, 26. 29. 30, 56, 193 Windom, H. L.. 34. 249, 250. 262 Winkler. P., 20 Winston, R. M., 58 Winterburg, S. H., I8 1 Wintrobe, M. M., 8 1 Wiseman, G., 82 Wisniewski. J., 30 Witz. S., 3 Wixson, B. G., 49. 172, 173 Wlochowicz, R.. 4 Wlodek. S.. 32 Wolff. E.. 149 Wofsy. s. c..20 Woidich, H.. 79 Woitowitz, R., 8 I

Wolf. W. R., 79. 80. 81, 91 Wolfram, W. E.. 150 Wolgemuth. K., 235 Wollast, R., 97. 237 Wolynetz, M . S., 103, 105, 106, 109, 124, 127, 130, 133, 135, 137, 141, 155, 158, 169, 189, 193 Wong, G. T. F.. 244, 245. 246, 257 Wong, J. J., 224, 230 Wong, Z. A,. 224 Wood, J . M., 72 Wood, 0. L., 8 1 Woodell, S. R. J., 125 Woodruff, N.P., 32 Woods, D. C., 8, 12 Woolson. A. E., 190, 191 Woosley. R. L.. 7 1 Wrathall. A. E., 222 Wren, A. G., 27 Wright, J . R., 127, 133, 137, 141, 169 Wright, T., 147 Wszolek, P. C.. 146 Wyllie, T. D.. 206. 218, 220, 223 Wynder, E. L.. 25 Yaalon, D. H.. 44. 128 Yamagami. Y., 145 Yamagata. N.. 79 Yamakawa. M., 8 0 Yamamori, Y.. 188 Y amamoto. T.. 8 0 Yamauchi, F.. 150 Yamawaki, T.. 79 Yamazaki. H., 252 Yamazaki, K., 206.2 I2 Yan, N . D., 54 Yanachkova, M., 199 Yanagisawa, S.. 193 Yanase, Y., 195 Yang, G., 2 18 Yang, S. L., 230 Yano, N., 23 1 Yaroshevskii, A. A.. 120 Yarovaya, G. A . , 122 Yeats, P. A,. 250. 253 Yeh, K. L., 167 Yluruokanen, I., 1 18, 203 Yokoyama, E., 200 Yost, K. J., 38 Young, J. A., 23 Young, J . W. S., 46 Young, R. S., 133 Younts, S. E., 100 Yuita, K., 185, 186. 188 Yung, S. C.. 63 Yung, Y. L., 20 Yunoki. E.. 8 0 Zablocki. Z.. 14 1 Zachariasen, H., 81.93 Zafiriou, 0. C.. 258

286 Zaidi, S. H., 59 Zaldivar, R., 88 Zaman, Q. U., 137, 141 Zanek, Z., 208 Zankl, B., 26 Zanzi, I., 84 Zaworowski. Z., 32 Zborishchuk. Yu. N., 121, 127. 133, 137, 139, 141, 157, 187 Zebel, G.. 4 Zeman, J., 114 Zenchelsky, S.. 33 Zettwoog. P., 35

Author Index Ziegler, E. L., 145 Zielinski. R. A.. 12 Zier, M.. 3 Zietecka, M., 125, 129 Zimdahl, R. L., 170, 172 Zimmerman. M., 103 Zimmerman, P. W., I52 Zimmerman, T. J.. 80 Zink, P., 8 1 Zitko, V., 87 Zmysowska, S., 197 Zobers, V., 37

Zoller. W. H.. I , 16. 17, 18. 34. 38.41. I I3 Zorn. H., 58 Zottl. H. W.. 101 Zuber, M . S.. 23 I Zubkov. A . I., 200 Zuev, V. E., 1 1 Zussman. J.. 164 Zvyagin, V. G.. 149 Zwarich. M . A.. 124. 154 Zyrin. N. G., 121, 127. 133, 137. 139, 141, 156. 157. 187

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