Disposal and Decontamination of Pesticides

Disposal and Decontamination of Pesticides

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Disposal and Decontamination of Pesticides M a u r i c e V. K e n n e d y , EDITOR Mississippi State

University

A symposium sponsored by the Division of Pesticide Chemistry at the 174th Meeting of the American Chemical Society, Chicago, Illinois, August 29September 2, 1977.

73

ACS SYMPOSIUM SERIES

AMERICAN WASHINGTON,

CHEMICAL D.

SOCIETY C.

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Library of Congress

Data

Main entry under title: Disposal and decontamination of pesticides. (ACS symposium; no. 73) Includes index and bibliographical references. 1. Pesticides—Environmental aspects—Congresses. I. Kennedy, Maurice V., 1925— . II. American Chemical Society. Division of Pesticide Chemistry. III. American Chemical Society. IV. Series: American Chemical Society. ACS symposium series; no. 73. TD196.P38D57 ISBN 0-8412-0443-0

668'.65

78-8645 ACSMC8 73 1-158

Copyright © 1978 American Chemical Society All Rights Reserved. The appearance of the code at the bottom of the first page of each article in this volume indicates the copyright owner's consent that reprographic copies of the article may be made for personal or internal use or for the personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per copy fee through the Copyright Clearance Center, Inc. for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to copying or transmission by any means—graphic or electronic—for any other purpose, such as for general distribution, for advertising or promotional purposes, for creating new collective works, for resale, or for information storage and retrieval systems. The citation of trade names and/or names of manufacturers in this publication is not to be construed as an endorsement or as approval by ACS of the commercial products or services referenced herein; nor should the mere reference herein to any drawing, specification, chemical process, or other data be regarded as a license or as a conveyance of any right or permission, to the holder, reader, or any other person or corporation, to manufacture, reproduce, use, or sell any patented invention or copyrighted work that may in any way be related thereto. PRINTED IN THE UNITED STATES OF AMERICA

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

ACS Symposium Series R o b e r t F . G o u l d , Editor

Advisory

Board

Kenneth B. Bischoff

Nina I. McClelland

Donald G. Crosby

John B. Pfeiffer

Jeremiah P. Freeman

Joseph V. Rodricks

E. Desmond Goddard

F. Sherwood Rowland

Jack Halpern

Alan C. Sartorelli

Robert A. Hofstader

Raymond B. Seymour

James P. Lodge

Roy L. Whistler

John L. Margrave

Aaron Wold

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

FOREWORD The ACS SYMPOSIUM SERIES was founded in 1974 to provide a medium for publishing symposia quickly in book form. The format of the SERIES parallels that of the continuing ADVANCES IN CHEMISTRY SERIES except that in order to save time the papers are not typeset but are reproduced as they are submitted by the authors in camera-ready form. As a further means of saving time, the papers are not edited or reviewed except by the symposium chairman, who becomes editor of the book. Papers published in the ACS SYMPOSIUM SERIES are original contributions not published elsewhere in whole or major part and include reports of research as well as reviews since symposia may embrace both types of presentation.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

PREFACE {

he d e c o n t a m i n a t i o n a n d d i s p o s a l of w a s t e p e s t i c i d e s is o n e o f

the

major p r o b l e m s f a c i n g t h e leaders i n m o d e r n a g r i c u l t u r e t o d a y .

It

poses m a n y c o m p l e x p r o b l e m s i n v o l v i n g other segments of society as w e l l . This, has b e c o m e a p p a r e n t i n r e c e n t years b y reports of v a r y i n g a m o u n t s of p e s t i c i d e c h e m i c a l s w i d e l y

d i s t r i b u t e d i n u n w a n t e d areas o w i n g

to

e i t h e r m i s u s e o r l a c k of i n f o r m a t i o n r e l a t i v e to d i s p o s a l . A l l of these c h e m i c a l s are n o t c o n f i n e d to d i r e c t a g r i c u l t u r a l use. M a n y are b y - p r o d u c t s o f o r m u l a t i o n of these p r o d u c t s .

Occasionally an industrial accident

release h a z a r d o u s c h e m i c a l s i n c l u d e d i n this g e n e r a l classification. ever, t h e f r e q u e n c y

will How-

of this o c c u r r i n g is s m a l l a n d i t c o u l d n o t b e c o n -

s i d e r e d to b e v e r y i m p o r t a n t . O n e of t h e m a i n reasons t h a t d e c o n t a m i n a t i o n a n d d i s p o s a l of these h a z a r d o u s w a s t e c h e m i c a l s is s u c h a c o m p l e x p r o b l e m i n v o l v e s t h e w i d e r a n g e of c h e m i c a l c o m p o u n d s w h i c h are u s e d as pesticides. F o r e x a m p l e , t w o classes of c o m p o u n d s — t h e o r g a n o c h l o r i n e s a n d the o r g a n o p h o s p h a t e s — v a r y g r e a t l y i n t h e i r response to m a n y of t h e m e t h o d s u s e d for d e c o n t a m i n a t i o n , a n d these are o n l y t w o of t h e classes of c o m p o u n d s u s e d as pesticides. T h i s w i d e r a n g e of c h e m i c a l s m a k e s r e s e a r c h e x t r e m e l y difficult, i f n o t i m p o s s i b l e , for p r o d u c i n g a s i n g l e m e t h o d for p e s t i c i d e d i s p o s a l t h a t a p p l i e s u n i v e r s a l l y . T h e r e f o r e , s e v e r a l m e t h o d s for d e c o n t a m i n a t i o n a n d d i s p o s a l of these u n w a n t e d c h e m i c a l s m a y b e r e q u i r e d to s o l v e this problem. T h e a i m of this v o l u m e is to present s e v e r a l m e t h o d s t h a t h a v e e i t h e r b e e n successful or s h o w a great d e a l of p r o m i s e i n t h e d e s t r u c t i o n of these c o m p o u n d s . T h e s e r e s e a r c h reports c o v e r a w i d e r a n g e o f m e t h o d s

and

s h o u l d b e h i g h l y a p p l i c a b l e to t h e major classes of p e s t i c i d e c h e m i c a l s i n use today. A p p r e c i a t i o n is expressed t o a l l of t h e authors of this p u b l i c a t i o n for the q u a l i t y of r e s e a r c h r e p o r t e d h e r e i n . It is h o p e d t h a t these i n v e s t i g a tions w i l l serve as a basis for f u r t h e r r e s e a r c h a n d t h a t t h e y e v e n t u a l l y w i l l l e a d to satisfactory solutions for a l l of these p r o b l e m s . M i s s i s s i p p i State U n i v e r s i t y

MAURICE V. KENNEDY

M i s s i s s i p p i State, M i s s i s s i p p i F e b r u a r y , 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1 Conquering the Monster—The Photochemical Destruction of Chlorodioxins D. G. CROSBY Department of Environmental Toxicology, University of California, Davis, CA 95616

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has become recognized as probably the most poisonous o fallsynthetic chemicals. In additiontohaving a embryotoxic, and causes (1). I t also has been considered to be very persistent (2) and to bioconcentrate i n animals. No wonder that a 1976 newspaper article referred toitas "the monsterous chemical" and that its detectable presence i n Vietnam War d e f o l i a n t s , commercial herbicides, and elsewhere i n the environment has caused so much apprehension and controversy. The use o f products which could contain chlorinated dibenzo-p-dioxins has been remarkably widespread (3). Pesticides such as 2,4,5-T, chlorophenols used f o r slime- and algae-control, and the common bactericide hexachlorophene--in f a c t , any chemical made from 2,4,5-trichlorophenol--might contain traces of TCDD. Commercial pentachlorophenol (PCP), used primarily as a preservative and i n s e c t i c i d e , contains hexa-, hepta-, and octachlorodioxins which can be reduced b i o l o g i c a l l y to less-chlorinated homologs; f o r example "chick-edema" disease has been traced to dioxins formed i n PCP-treated hides from which a poultry-feed supplement was derived (4). The manufacture of chlorophenols, e s p e c i a l l y , has led on occasion t o severe toxicological problems such as those encountered i n a 1976 accident at Seveso, Italy. E a r l i e r work indicated that pure TCDD was almost inert toward attack by microorganisms, other biological breakdown, and environmental forces (2). This is not s t r i c t l y true; under certain conditions, i t Ts very unstable to u l t r a v i o l e t (UV) l i g h t (5). The purpose of the present paper i s to define the photochemical c r i t e r i a f o r that i n s t a b i l i t y , describe laboratory experiments concerned with i t , and indicate how i t might be applied f o r the intentional destruction o f "the monstrous chemical" and i t s r e l a tives.

0-8412-0433-0/78/47-073-001$05.00/0 © 1978 A m e r i c a n C h e m i c a l Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Background

Photochemistry

The photochemical replacement of halogen atoms on aromatic rings by hydrogen has been known for some time. For example, the i r r a d i a t i o n of pentachlorophenol in hexane with UV l i g h t produced tetrachlorophenols, pentachloronitrobenzene (PCNB) was reduced to tetrachloronitrobenzenes and pentachlorobenzene, and polychlorobenzenes were further dechlorinated (6) ( F i g . 1). However, thin films of the pure compounds were not appreciably affected; some donor of hydrogen atoms also was necessary for the reaction. Organic solvents serve this purpose admirably, although photoreduction experiments with chlorobenzoic acids revealed that the chemical nature of that solvent could strongly influence the rate of reaction (7). Although photonucleophili halides have been show most evidence for the mechanism of reductive dechlorination in organic solvents supports an i n i t i a l homolysis of the r e l a t i v e l y weak C-Cl bond followed by abstraction of the hydrogen atom from solvent by the resulting phenyl radical ( F i g . 2). For example, when the solvent i s benzene, phenylation rather than hydrogénation often predominates (9), and the above-mentioned photoreduction of PCNB i n hexane also produced the three isomeric chlorohexanes by transfer of chlorine atoms (6). This mechanistic problem i s by no means solved, but Nordblom and M i l l e r (7) confirmed that the chlorine-replacing hydrogen indeed i s derived by breaking C-H bonds of the solvent. As might be expected, this reductive dechlorination of polyhalogenated compounds takes place stepwise (Fig. 3). UV i r r a d i a tion of tetrachlorobiphenyl s in organic solvents produced corresponding t r i - , d i - , and monochlorobi phenyl s, but the monochloro compound proved to be e s s e n t i a l l y stable toward further reaction due to n e g l i g i b l e absorption of the l i g h t energy provided (10). The same phenomenon has been observed in the photoreduction of chlorinated benzonitriles (11); the rate of the primary homolytic (bond-breaking) process in We halide i s dependent upon the degree of l i g h t absorption as measured by the compound's molar extinction c o e f f i c i e n t , ε . Consequently, the relationship of the incident l i g h t to the UV absorption spectrum of the halide as well as to that of any other strongly-absorbing compound present becomes extremely important. It i s apparent that three conditions must exist in order f o r photoreduction of chlorinated aromatic com­ pounds to take place: a hydrogen-donating solvent must be pre­ sent, UV l i g h t of appropriate wavelength must impinge on the solution, and that l i g h t must be absorbed. The energy available in natural sunlight l i m i t s the photo­ reduction of many chemicals in the environment. Sunlight inten­ s i t y drops o f f abruptly below about 310 nm (Fig. 4) and becomes n e g l i g i b l e below about 290 nm. Consequently, i t i s not surprising that 3,3* ,4,4*-tetrachlorobiphenyl (ε = 6740 at 290 nm) i s readily

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Photochemical Destruction of Chlorodioxins

CROSBY

Figure 1.

h v

ArCl

Ar- + C H g

C1

. C H +

Photodecomposition products from PCNB in hexane

6

1 4

1 3

Ar* + Α γ · C

H

6 13-

+

C

>• Ar- + CI-

Primary Process

>- ArH + CgH^*~

C H C1 6

Reactions

13

>- Af£ H

6 13

C

H

12 26

SideReactions

Etc. Figure 2.

Proposed mechanism of photochemical reduction of aromatic halides in an organic solvent (e.g., hexane)

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Wavelength, nm Figure 4.

Spectral energy distribution of sunlight

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1.

CROSBY

5

Photochemical Destruction of Chlorodioxins

reduced at sunlight wavelengths ( 7 J 0 ) , while 4-chlorobiphenyl i s r e l a t i v e l y stable (ε = 10 at 310 nmTT only substances which absorb UV l i g h t above 290 nm can be expected to react. Chlorodioxins Like other chlorinated aromatic compounds, chlorodioxins are reductively dechlorinated when t h e i r solutions in organic solvents are irradiated with appropriate wavelengths of UV l i g h t (12). Exposure of a d i l u t e methanol solution of TCDD ( X 306 nm, ε = 6000) to l i g h t from a fluorescent UV lamp caused rapid degradation (Fig. 5); the i n i t i a l product, 2,3,7-trichlorodibenzo-p-dioxin, which exhibits a very similar absorption spectrum but has only about half the molar extinction (Xm 304 nm, ε = 3500), slowly accumulated and then i t s e l chlorodibenzo-p-dioxin (0CDD) reacted even more slowly (Fig. 6). Less-chlorinated photoreduc­ tion products were readily detected and i d e n t i f i e d by gas chroma­ tography and mass spectrometry in each instance. Pure, c r y s t a l l i n e TCDD was stable to sunlight wavelengths when applied as thin films to glass (5) or leaves (12) or suspend­ ed in water (3). Apparently, the c r y s t a l l i n e state prohibits TCDD molecules from losing s i g n i f i c a n t chlorine or from abstracting hydrogen atoms from each other. However, when dissolved in methanol (5), diesel o i l (13), or l i q u i d phenoxy ester (13), photoreduction was complete a f t e r a few hours exposure to outdoor sunlight. Again, trichloro-and dichloro-homologs were detected during photolysis, but they in turn eventually were dechlorinated to nontoxic dibenzo-p-dioxin which i t s e l f underwent further photodegradation (.3). This suggests that TCDD may decompose under many practical application conditions and that i t even could be intentionally destroyed as long as the three photochemical c r i ­ t e r i a c i t e d above were s a t i s f i e d . m a x

1

Practical Applications Continuing concern has been expressed over the presence of small but detectable levels of TCDD in commercial herbicide formu­ l a t i o n s . T y p i c a l l y , such formulations are composed of roughly equal amounts of l i q u i d esters of 2,4-D (2,4-dichlorophenoxyacetic acid) and 2,4,5-T (2,4,5-tri chlorophenoxyaceti c a c i d ) , usually dissolved in o i l or emulsified in water (Table I ) . The fear i s that the contained dioxin--currently less than 0.1 ppm but o r i g i n ­ a l l y as much as 100 times more than that—might p e r s i s t and bioconcentrate following f i e l d application of herbicides.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

6

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 5.

Stepwise photoreduction of

TCDD

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1.

CROSBY

7

Photochemical Destruction of Chlorodioxins

Table I. Composition of Herbicide Sprays Esteron Brush-killer Water 2,4-D propylene glycol ether esters 2,4,5-T propylene glycol ether esters Organic solvent and emulsifier

Lbs/Acre 100

Agent Orange 2,4-D η-butyl ester 2,4,5-T η-butyl ester Alcohols, acids, etc. equivalent to 1 lb/acr equivalent to 13.8 lbs/acre 2,4,5-T („20 mg/acre TCDD); see Ref. 22. The herbicide esters should serve adequately as H-donors, TCDD absorbs l i g h t within the wavelength range of sunlight, and the thin films of applied chemicals do not completely mask this UV absorption (14). Consequently, when herbicide was applied to a leaf surface"T[3), the breakdown of TCDD was found to be rapid upon exposure to sunlight (Fig. 7). Photochemical breakdown also occurred on the surface of s o i l , although once s u f f i c i e n t herbi­ cide had been applied so that i t penetrated, the subsurface por­ tion no longer was exposed to l i g h t and the degradation presumably ceased. Because much of the UV l i g h t reaching the earth's surface comes from open sky (15), exposure to d i r e c t sunlight was not required, but breakdown would be expected to be slower in the shade. Despite recent furor over the continued use of 2,4,5-T in Western f o r e s t s , no actual measurements of dioxin dissipation from herbicide-treated forest appear to have been reported. However, the breakdown observed upon application to broad!eaved plants (13) might be expected to take place in other locations as w e l l , pro­ vided that the three c r i t e r i a for photoreduction were met. Getzendaner and coworkers indeed have shown (16) that TCDD was l o s t smoothly from 2,4,5-T treated range grass, the h a l f - l i f e being roughly 4 days. Evidently, the photochemical destruction of TCDD takes place under f i e l d conditions. Analysis of TCDD residues in the presence of the large excess of phenoxy esters proved troublesome. The procedure was greatly simplified by a l k a l i n e hydrolysis of the esters, removal of the neutral dioxin into inert solvent (such as benzene), concentration of the extract, and gas chromatography of the dioxins with either an electron-capture or mass spectrometer detector (13). This p r i n c i p l e of herbicide hydrolysis fol1 owed by extraction of dioxin from the alkaline hydrolyzate was applied by the Velsicol Chemical

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

8

Corporation of Chicago to a process aimed at p r a c t i c a l u t i l i z a t i o n of the m i l l i o n s of gallons of leftover Agent Orange (mixed butyl esters of 2,4-D and 2,4,5-T) stored by the U.S. A i r Force. V e l s i c o l ' s method u t i l i z e d the η-butyl alcohol resulting from the hydrolysis of the phenoxy acid butyl esters as part of the extrac­ tion solvent; the dioxin-containing organic extract was continu­ ously subjected to UV i r r a d i a t i o n i n a separate reactor to produce a harmless residue which could be safely incinerated, while the dioxin-free mixture of 2,4-D and 2,4,5-T salts remaining i n the aqueous layer could be reprocessed and f o r t i f i e d to provide a useful registered herbicide. The photochemical destruction of TCDD apparently i s applicable to appropriate industrial process­ ing. The release of TCDD has not always been under such close control; i n f a c t , severa human i l l n e s s and sever overheated s t i l l at a trichlorophenol plant i n Seveso, I t a l y , released a cloud of sodium trichlorophenate which contained thermally-generated TCDD. The p a r t i c l e s s e t t l e d out over several hundred acres of primarily agricultural grassland and trees as well as a number of dwellings. In the most highly contaminated area, grass levels reached many micrograms per square meter (yg/m ), while the leaves of nearby trees contained as much as 2.5 milligrams of TCDD per kilogram of wet weight. Human contact with levels exceeding about 0.5 yg/m i s considered extremely danger­ ous. Extensive a n a l y t i c a l work by both the Italian Government and the owner of the factory (Givaudan Corporation) showed that the TCDD residues were d i s s i p a t i n g very slowly; although the sunlight was adequate and the TCDD absorption appropriate, e f f e c t i v e con­ tact with photochemical Η-donors was minimal. Application of a number o f harmless solvents to a r t i f i c i a l l y provide the needed hydrogen was considered but was rejected by a people who f e l t that they already had been sprayed with enough chemicals. F i n a l l y , Givaudan chemists offered an acceptable hydrogen d o n o r — o l i v e o i l . The locally-purchased o i l was applied experimentally by sprayer to a highly contaminated area of glassland as a 40% aqueous emulsion (400 1/ha) or 80% solution i n cyclohexanone (350 1/ha) to produce a p r a c t i c a l l y continuous f i l m on vegetation and other surfaces (17). As seen i n Table I I , reduction of the r e s i ­ due levels i n the treated plots was rapid while controls remained v i r t u a l l y unchanged, although a period of rain washed a large proportion of the control TCDD onto the s o i l . Despite consider­ able v a r i a b i l i t y when the analytical values were plotted against time, a plot against accumulated (integrated) u l t r a v i o l e t energy (Fig. 8) provided a clear demonstration of photochemical decompo­ s i t i o n which, i n the case of the o l i v e o i l solution, resulted i n the destruction of almost 90% of the TCDD within 9 days. In view of t h i s , i t was hoped that dioxin could be reduced to a tolerable level over the entire area-at least enough to permit safe harvest2

2

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

CROSBY

Photochemical Destruction of Chlorodioxins

Ο

δ

10 315 nm

©

ΧΙΟ

Integral

Figure 8. Photodecomposition rates of TCDD on grass after treat­ ment with olive oil emulsion (E) or olive oil solution in cyclohexanone (S) compared with an untreated control (C). Based upon data of Homberger et al (17) from experiments at Seveso, Italy, September 7-16, 1976. Circles show sampling times; UV integral in arbitrary energy units.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

10

DISPOSAL AND DECONTAMINATION OF PESTICIDES

ing of the foliage with TCDD s t i l l in place—and that the people of Seveso could return to t h e i r homes before winter. Table I I . TCDD,on Grass (yg/m ) 2

Day 0 1 2 3 4 8 9 a

a

Olive O i l Emulsion

Olive O i l Solution

Control

26.2 16.9 9.6

19.5 18.8 10.7

16.4 18.5 16.4

2.3

3.3

Rain 5.2

Homberger et al.,. 1976.

Conclusions Although the chemical mechanism which underlies TCDD photoreduction s t i l l may be obscure, the application of the principle now seems clear enough. For reaction of halogenated aromatic compounds (and perhaps nitro compounds, ni t r i les, and some others) to occur, three factors are required: a v a i l a b i l i t y of UV l i g h t ; absorption of the l i g h t by the chemical; and the proximity of a hydrogen-donating solvent. Although intensity varies from location to location, the energy required f o r photoreduction usually i s present. The UV portion of sunlight offers s u f f i c i e n t quantum energy to dissociate both aromatic C-Cl bonds (about 97 kcal/Einstein, corresponding to 294 nm) and a l i p h a t i c C-H bonds (about 94 kcal/Einstein, or 303 nm) (18). A major part of this l i g h t reaches earth by r e f l e c t i o n and dispersion from open sky rather than from direct sunlight ( 1 5 ) — i n the long summer days of the Northern Hemisphere, the time wuên most pesticides are applied, Barrow, Alaska, receives at least as much total sunlight energy as Miami, Florida (18). The UV radiation readily penetrates water (19), and recent estimates have shown that a s i g n i f i c a n t proportion penetrates the leaf canopy of a forest or orchard (20). Many aromatic compounds, including the dioxins, absorb appreciable energy within the UV portion of the solar spectrum (above 290 nm). Although that energy can be l o s t as heat, fluorescence, or nonreactive impact with other molecules, the accumulating evidence shows that reactions with environmental reagents are prevalent (21). For photoreductions, the hydrogen-donating s o l vent could B ê a pesticide or formulating agent, leaf waxes, the natural organic f i l m which covers most natural water, or even

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1.

CROSBY

Photochemical Destruction of Chlorodioxins

11

inadvertent and otherwise undesirable pollutants such as s p i l l e d o i l . Although photoreduction i s hardly a panacea, i t obviously holds promise f o r the natural deactivation of residual chemicals, the destruction of toxic wastes from manufacturing, and even the intentional decontamination of polluted environments. In view of t h i s , what u t i l i z a t i o n has been made of the pract i c a l applications of photochemical reduction demonstrated above? None. Rather than attempt to determine whether or not TCDD actually was present i n herbicide formulations applied to Western forests, f o r example, or to measure i t s dissipation i n a forest environment, considerable e f f o r t has been expanded toward trying to demonstrate i t s presence i n local human milk at or below the l i m i t of analytical real l a b i l i t y ; the fear and controversy continue. Despite presentation of a safe, practical process f o r the economical recovery of ously impractical remova t r i e d , abandoned, and the decision f i n a l l y was made by the U.S. A i r Force to burn the material at sea. The Italian government hesitated too long to reduce TCDD levels on f o l i a g e , and winter rains and leaf f a l l carried most of the chemical into the s o i l ; they now are considering construction of what may be one of the world's largest kilns i n which to "burn" s o i l and organic matter, turning the Seveso agricultural area into a wasteland. In each instance, there i s evidence that decision-makers f a i l e d to comprehend the firm s c i e n t i f i c principles upon which the application was based. Distressing as they may be, these disappointments underscore several important conclusions: — Laboratory investigations i n environmental chemistry must more closely simulate the physical and chemical microenvironment i n which toxic chemicals actually exist i f v a l i d conclusions about transformations (and movement) are to be drawn; — Formulating agents play a more important part i n the environmental fate of pesticides than previously has been supposed; — TCDD and related chlorodioxins, no matter how toxic and dangerous, are only chemicals and obey known physical and chemical p r i n c i p l e s . — Chemists must become much more proficient and forceful in conveying these principles to news media, the public, and society's leaders i f maximum u t i l i z a t i o n i s to be achieved i n applying chemistry f o r mankind's benefit. Literature Cited 1. Schwetz, B.A., J.M. Morris, G.L. Sparschu, V.K. Rowe, and P.J. Gehring, Adv. in Chem. Ser. 120, 55 (1973). 2. Kearney, P.C., A.R. Isensee, C.S. Helling, E.A. Woolson, and J.R. Plimmer, Adv. in Chem. Ser. 120, 105 (1973).

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3. Plimmer, J.R., U.I. Klingebiel, D.G. Crosby, and A.S. Wong, Adv. in Chem. Series 120, 44 (1973). 4. Higginbotham, J.R., A. Huang, D. Firestone, J . Verrett, J . Ress, and A.D. Campbell, Nature 220, 702 (1968). 5. Crosby, D.G., A.S. Wong, J.R. Plimmer, and U.I. Klingebiel, Science 173, 748 (1971). 6. Crosby, D.G., and N. Hamadmad, J. Agr. Food Chem. 19, 1171 (1971). 7. Nordblom, G.D., and L.L. Miller, J. Agr. Food Chem. 22, 57 (1974). 8. Crosby, D.G., K.W. Moilanen, M. Nakagawa, and A.S. Wong, in "Environmental Toxicology of Pesticides" (F. Matsumura, G.M. Boush, and T. Misato, eds.), Academic Press, New York, 1973, p. 423. 9. Plimmer, J.R., and 1968, 20. 10. Ruzo, L.O., M.J. Zabik, and R.D. Schuetz, J . Agr. Food Chem. 22, 199 (1974). 11. Plimmer, J.R., Residue Reviews 33, 47 (1970). 12. Isensee, A.R., and G.E. Jones, J . Agr. Food Chem. 19, 1210 (1971). 13. Crosby, D.G., and A.S. Wong, Science 195, 1337 (1977). 14. Crosby, D.G., K.W. Moilanen, and A.S. Wong, Environ. Health Perspectives 5, 259 (1973). 15. Koller, L.R., " U l t r a v i o l e t Radiation," 2nd ed., Wiley, New York, 1965. 16. Getzendaner, M.E, Ag-Organics Department, Dow Chemical USA, Midland, Mich. Personal Communication. 17. Homberger, E., N. Neuner, F. Schenker, and H.K. Wipf, Workshop on 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), University of Milan, October 23/24, 1976. 18. Crosby, D.G., Herbicide Photodecomposition, in "Herbicides: Chemistry, Degradation, and Mode of Action" (P.C. Kearney and D.D. Kaufman, eds.), Vol. 2, Marcel Dekker, New York, 1976, p. 835. 19. Zepp, R.G., and D.M. Cline, Environ.Sci.Technol. 11, 359 (1977). 20. Allen, L.H., H.W. Gausman, and W.A. Allen, J. Environ. Qual. 4, 285 (1975). 21. Crosby, D.G., ACS Sympos. Ser. 37, 93 (1977). 22. National Research Council, "The effects of herbicides in South Vietnam," National Academy of Sciences, Washington, D.C., 1974. MARCH 23,

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2 Approaches to Decontamination or Disposal of Pesticides: Photodecomposition JACK R. PLIMMER Organic Chemical Synthesis Laboratory, Federal Research, Science, and Education Administration, USDA, Beltsville, MD 20705

The g u i d e l i n e s f o r the d i s p o s a l o f s m a l l q u a n t i t i e s o f unused p e s t i c i d e s i s s u e d b y the Environmental P r o t e c t i o n Agency i n 1975 make it clear that there is still a great need f o r satisf a c t o r y d i s p o s a l technique cally the g u i d e l i n e s s t a t u r g e n t l y needed f o r those p e s t i c i d e s t h a t do not have a c c e p t a b l e d i s p o s a l procedures a t present and a r e e i t h e r : (a) extremely dangerous to man and wildlife because o f their h i g h toxicity; (b) not, o r o n l y s l o w l y degraded to nontoxic products in t h e environment; o r (c) produced in the l a r g e s t q u a n t i t i e s . P e s t i c i d e s in these c a t e g o r i e s i n c l u d e the organomercury and organoa r s e n i c compounds, t h a l l i u m sulfate, d i a z i n o n , methyl p a r a t h i o n , p a r a t h i o n , phorate, maneb, alachlor, CDAA, p r o p a c h l o r , a t r a z i n e , DDT, h e p t a c h l o r , toxaphene, l i n d a n e , chloramben, 2,4-D, 2 , 4 , 5 - T , aldrin, chlordane, e n d r i n , pentachlorophenol and 2,4,6-trichlorophenol" (1). Photochemical d e s t r u c t i o n o f organic m a t e r i a l has not achieved the s t a t u s o f a t e c h n o l o g i c a l process t h a t is a p p l i c a b l e on a l a r g e s c a l e ; indeed, its potential f o r d e t o x i c a t i o n o f wastes o r r e n d e r i n g them more s u s c e p t i b l e t o m i c r o b i a l degradat i o n has been l i t t l e explored. There i s an important need t o develop more data on r a t e s and e f f i c i e n c i e s o f photochemical r e a c t i o n s . Without t h i s b a s i c d a t a , there i s l i t t l e p o i n t i n d i s c u s s i n g the q u e s t i o n o f i n s t a l l a t i o n d e s i g n and c a l c u l a t i o n of o p e r a t i n g c o s t s . I n t h i s d i s c u s s i o n I would l i k e t o o u t l i n e some l i m i t i n g f a c t o r s and i n d i c a t e areas where progress i s desirable. M i c r o b i a l a c t i o n and the e f f e c t o f s u n l i g h t are two major f a c t o r s r e s p o n s i b l e f o r t r a n s f o r m a t i o n of p e s t i c i d e s i n the environment. I f the p e s t i c i d e i s a p p l i e d as a spray, a subs t a n t i a l p r o p o r t i o n o f the a p p l i e d m a t e r i a l may not reach the t a r g e t s i t e and an a p p r e c i a b l e amount may be l o s t by v o l a t i l i z a t i o n . P e s t i c i d e s v a p o r i z i n g from s u r f a c e s o r d u r i n g spray a p p l i c a t i o n may be transformed by p h o t o l y s i s i n the vapor phase; s i m i l a r l y p e s t i c i d e s i n water o r present on environmental 0-8412-0433-0/78/47-073-013$05.00/0 This chapter not subject to U.S. copyright. Published 1978 A m e r i c a n C h e m i c a l Society

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surfaces may be a l t e r e d c h e m i c a l l y by s o l a r r a d i a t i o n . I f s m a l l q u a n t i t i e s of p e s t i c i d e s are exposed to the prolonged a c t i o n of a i r , s u n l i g h t and m i c r o b i a l degradation, i t i s to be a n t i c i p a t e d t h a t i n most cases there w i l l be r a p i d breakdown t o simpler molecules. The problems i n v o l v e d i n i n t e n t i o n a l decontamination and d i s p o s a l of concentrated p e s t i c i d e wastes are somewhat d i f f e r e n t . I n c i n e r a t i o n appears to have g r e a t e s t p r a c t i c a l p o t e n t i a l as a d i s p o s a l technique when s u b s t a n t i a l q u a n t i t i e s of s u r p l u s combustible m a t e r i a l s are concentrated a t a s i n g l e l o c a t i o n . I t p r o v i d e s a complete s o l u t i o n to many problems of chemical d i s p o s a l , but i t i s important t h a t the c o n d i t i o n s r e q u i r e d f o r the combustion of each chemical be p r e v i o u s l y determined and t h a t the f l u e gases be e f f i c i e n t l y cleaned and monitored to ensure that no t o x i c m a t e r i a l s are equipment t h a t i s c o s t l I f l a r g e volumes of m a t e r i a l s are to be handled, other options may be p r e f e r a b l e . S o i l d i s p o s a l o f f e r s a f e a s i b l e and economically a t t r a c t i v e a l t e r n a t i v e , but s u i t a b l e s i t e s are l i m i t e d and the c o r r e c t choice of s i t e i s of c r i t i c a l importance (3). D i l u t e aqueous wastes may be a p p l i e d to s u i t a b l y c o n s t r u c t ed s o i l d i s p o s a l areas or p u r i f i e d by passage through p e r c o l a t i o n beds and h o l d i n g tanks. S o i l d i s p o s a l r e l i e s on m i c r o b i a l a c t i o n to transform p e s t i c i d e s i n t o simple innocuous molecules. This process, i n v o l v i n g conversion of complex molecules to carbon d i o x i d e , water, c h l o r i d e i o n e t c . , i s g e n e r a l l y r e f e r r e d to as "mineralization". We can a l s o add chemical treatment and i r r a d i a t i o n to the processes of m i c r o b i a l a c t i o n and i n c i n e r a t i o n as ways to reduce the hazards of s u r p l u s p e s t i c i d e s . Chemical treatment of organic compounds may i n c l u d e r e a c t i o n s such as conversion t o carbon t e t r a c h l o r i d e by the process of c h l o r i n o l y s i s , which i m p l i e s r e a c t i o n w i t h gaseous c h l o r i n e under vigorous c o n d i t i o n s . Treatment w i t h other reagents such as sodium hydroxide may be used; f o r example, a strong base r a p i d l y increases the r a t e of h y d r o l y s i s of organophosphorus p e s t i c i d e s such as p a r a t h i o n . Thus t o x i c i t y may be s u b s t a n t i a l l y reduced. A v a r i e t y of chemical treatments have been i n v e s t i g a t e d . Kennedy et a l . (4) found t h a t s e v e r a l p e s t i c i d e s could be e f f e c t i v e l y degraded by d i s s o l v i n g metal r e d u c t i o n (sodium i n l i q u i d ammonia). Organochlorine compounds present a p a r t i c u l a r problem. The EPA g u i d e l i n e s s t a t e t h a t "the only acceptable d i s p o s a l procedure f o r these p e s t i c i d e s i s i n c i n e r a t i o n . However, i n most cases, complex i n c i n e r a t i o n equipment i s r e q u i r e d i n order t o assure that s u f f i c i e n t l y h i g h temperatures are developed, and to prevent atmospheric contamination by combustion products. Furthermore, i n c i n e r a t i o n i s p r a c t i c a l o n l y on a v e r y l a r g e s c a l e and i s uns u i t e d t o the s m a l l batch operations which c h a r a c t e r i z e most pesticide disposal situations. "We recommend t h a t a study be made of other techniques

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I n p a r t i c u l a r , we recommend t h a t a study be made of a d i s p o s a l procedure which employs both h y d r o l y s i s and o x i d a t i o n " ( 1 ) . I n such cases, I suggest t h a t the p o s s i b i l i t y of u s i n g i r r a d i a t i o n followed by m i c r o b i a l degradation should a l s o be examined as an a l t e r n a t i v e method t o reduce the hazard of d i l u t e aqueous wastes. Aqueous systems c o n t a i n i n g p a r t s per m i l l i o n or l e s s of c h l o r i n a t e d compounds or other t o x i c organic wastes may be i r r a d i a t e d to reduce t h e i r t o x i c i t y and a l s o to reduce t h e i r " r e c a l c i t r a n c e " . I f some p a r t s of the molecules can be modified i n t h i s way, they may be rendered more s u s c e p t i b l e to degradation by microorganisms. For example, a r e d u c t i o n i n the number of c h l o r i n e atoms attached to an aromatic r i n g w i l l g e n e r a l l y i n crease the r a t e of decomposition by microorganisms. The breakdown of (2,4-dichlorophenoxy)acetic a c i d by s o i l microorganisms i s much more r a p i d tha acid. Similarly polychlorinate halogen s u b s t i t u e n t s are more r e a d i l y degraded than the more h i g h l y s u b s t i t u t e d molecules ( 5 ) . P h o t o l y s i s as a method f o r the i n t e n t i o n a l d e s t r u c t i o n of p e s t i c i d e s would appear to have great p o t e n t i a l . S u n l i g h t as a source of r a d i a n t energy i s f r e e l y a v a i l a b l e , and s o l a r r a d i a t i o n i s a potent agent f o r the d e s t r u c t i o n of many man-made chemicals i n the environment. I n f a c t , i t i s v e r y d i f f i c u l t to s y n t h e s i z e organic chemicals t h a t can r e s i s t the a c t i o n of sun and a i r f o r long p e r i o d s . Water i s p u r i f i e d by the a c t i o n of a i r and s u n l i g h t . Many t o x i c chemicals, such as the c h l o r o d i o x i n s , may be decomposed by u l t r a v i o l e t r a d i a t i o n (6,7)· Most p e s t i c i d e s on u l t r a v i o l e t i r r a d i a t i o n u l t i m a t e l y a f f o r d products that are much l e s s t o x i c or hazardous to the e n v i r o n ment than the o r i g i n a l m a t e r i a l . I t may be p o s s i b l e t o take p r a c t i c a l advantage of t h i s f a c t i f we are w i l l i n g to examine the requirements and l i m i t a t i o n s of photochemical r e a c t i o n s . Questions that must be considered i n c l u d e the f o l l o w i n g : 1) How r a p i d l y do photochemical r e a c t i o n s occur and what energy input i s necessary? 2) What products are to be a n t i c i p a t e d and how are they a f f e c t e d by the p h y s i c a l s t a t e of the reactants? How R a p i d l y do Photochemical Reactions Occur and What are Energy Requirements?

Their

Most organic compounds can be decomposed by thermal energy, a process that u s u a l l y takes p l a c e r a p i d l y . How u s e f u l i s u l t r a v i o l e t i r r a d i a t i o n , i f we w i s h to achieve a s i m i l a r e f f e c t ? F i r s t , the rupture of a chemical bond r e q u i r e s a d e f i n i t e amount of energy. Because the d i s s o c i a t i o n of a carbon-carbon bond r e q u i r e s an input of about 100 k i l o c a l o r i e s per mole, we must use l i g h t possessing a t l e a s t t h a t amount of energy. The energy of electromagnetic r a d i a t i o n i s i n v e r s e l y p r o p o r t i o n a l to i t s wavelength so the source must provide a s a t i s f a c t o r y output of energy a t low wavelengths. A f r e q u e n t l y used source f o r

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photochemical r e a c t i o n s i s the medium p r e s s u r e mercury a r c , w i t h maximum energy d i s t r i b u t i o n around 254 nm. T h i s source must be housed i n quartz to permit the passage of low wavelengths. Secondly, the r a t e of p h o t o l y s i s depends on s e v e r a l f a c t o r s . D i r e c t p h o t o l y s i s of an o r g a n i c compound i n s o l u t i o n r e q u i r e s that l i g h t must be absorbed f o r r e a c t i o n to occur. L i g h t energy i s measured i n quanta. The number of l i g h t quanta absorbed by the r e a c t a n t d i v i d e d i n t o the number of molecules of p h o t o l y s i s product formed measures the e f f i c i e n c y , or 'quantum y i e l d ' , of the p r o c e s s . However, the quantum y i e l d of a photochemical r e a c t i o n does not p r o v i d e a good i n d i c a t i o n of the r e a c t i o n r a t e because i t i s o n l y one f a c t o r i n determining the r a t e , which a l s o depends on the r a t e of a b s o r p t i o n of l i g h t by the system and the f r a c t i o n of absorbed l i g h t t h a t produces the r e a c t i v e s t a t e (8). Therefore the sourc i e n t energy i n terms o supply s u f f i c i e n t i n t e n s i t y i n terms of r a d i a n t energy output over u n i t time. A b s o r p t i o n o f l i g h t by the molecule i s d e f i n e d a t any wavel e n g t h by the shape of i t s a b s o r p t i o n curve. Benzenoid compounds g e n e r a l l y absorb l i g h t weakly around 300 nm, which corresponds to the r e g i o n of the s o l a r spectrum p r o v i d i n g most energy. Cyclodiene i n s e c t i c i d e s such as a l d r i n or d i e l d r i n do not absorb l i g h t except a t wavelengths below 250 nm. Such r a d i a t i o n r e q u i r e s an u n f i l t e r e d mercury a r c source. I used the term 'quantum y i e l d ' to i n d i c a t e the e f f i c i e n c y of the photodecomposition p r o c e s s . I t must be r e c o g n i z e d t h a t the a b s o r p t i o n of l i g h t does not l e a d t o decomposition i n every case, even though the l i g h t may have s u f f i c i e n t energy to break chemical bonds. The energy absorbed by the molecule l e a d s to e x c i t a t i o n . I n a d d i t i o n to decomposition, l o s s of energy from the e x c i t e d s t a t e may occur by f l u o r e s c e n c e , e x c i t a t i o n of another molecule, e t c . D i s s o c i a t i o n o f a bond r e p r e s e n t s o n l y one of the p o s s i b l e modes of energy l o s s . How Can Some of the L i m i t a t i o n s be Overcome? The requirement t h a t the r a d i a t i o n c o n t a i n energy o f s u f f i c i e n t l y short wavelengths t o cause d i s s o c i a t i o n of a chemical bond a p p l i e s o n l y to the d i r e c t a b s o r p t i o n of energy by the r e a c t i n g molecule; a l t e r n a t i v e processes can f a c i l i t a t e the i n d u c t i o n of photochemical r e a c t i o n by l i g h t of longer wavelengths. S e n s i t i z a t i o n r e p r e s e n t s an example o f such a p r o c e s s . A m i t r o l e i s r e s i s t a n t to the d i r e c t a c t i o n of l i g h t of wavelengths g r e a t e r than 260 nm, i t begins t o absorb l i g h t a t s h o r t e r wavel e n g t h s , and i t i s p h o t o c h e m i c a l l y s t a b l e . However, i n the presence of r i b o f l a v i n , a m i t r o l e i n aqueous s o l u t i o n i s r a p i d l y degraded by l i g h t of wavelengths above 300 nm ( 9 ) . S i m i l a r l y , the c y c l o d i e n e i n s e c t i c i d e s i n the presence o f acetone, which absorbs l i g h t a t 290 nm, undergo photochemical r e a c t i o n s .

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S e n s i t i z e d processes i n v o l v e the t r a n s f e r of energy from a molecule t h a t has absorbed l i g h t and become e x c i t e d to a h i g h e r energy s t a t e ( u s u a l l y a " t r i p l e t " s t a t e ) . C o l l i s i o n s t h a t t a k e place during t h i s r e l a t i v e l y long-lived " t r i p l e t " state r e s u l t i n t r a n s f e r of energy from the e x c i t e d molecule t o a second molecule, which becomes the r e a c t a n t . Thus, photochemical r e a c t i o n occurs w i t h o u t d i r e c t a b s o r p t i o n of l i g h t by the r e a c t i n g molecule. Another type of energy t r a n s f e r i n v o l v e s "charge t r a n s f e r " mechanisms. For example, the photodecomposition of halogenated aromatic compounds such as DDT i s f a c i l i t a t e d i n the presence of amines. Halobenzenes f u n c t i o n as e l e c t r o n acceptors i n the formation of e x c i t e d c h a r g e - t r a n s f e r complexes w i t h amines, and p h o t o l y s i s of the c h a r g e - t r a n s f e r complexes may occur a t much lower wavelengths than alone. S e n s i t i z e r s a r e abundant i n " n a t u r a l " waters and account f o r the enhanced r a t e s of p h o t o l y s i s of p o l l u t a n t s i n streams and r i v e r s . Even though the body of water may appear opaque or darkc o l o r e d t o the o b s e r v e r , r a t e s of p h o t o l y s i s near the s u r f a c e are more r a p i d than i n d i s t i l l e d water. The n a t u r e of " n a t u r a l " p h o t o s e n s i t i z e r s has r e c e i v e d a t t e n t i o n . Ross and Crosby (10) examined the p h o t o o x i d a t i o n of a l d r i n and found t h a t i n the presence o r absence of l i g h t of wavelengths g r e a t e r than 300 nm, a l d r i n (10 p g / l . ) was s t a b l e t o l i g h t i n d e m i n e r a l i z e d water. A l d r i n does not absorb l i g h t above 250 nm, but i n the presence of 0.1% of the t r i p l e t s e n s i t i z e r s , acetone or acetaldehyde, a l d r i n was p h o t o o x i d i z e d t o d i e l d r i n . S i n g l e t oxygen d i d not appear t o be i m p l i c a t e d i n t h i s c o n v e r s i o n , nor were photoi s o m e r i z a t i o n products detected i n these experiments. I t was suggested t h a t the f o r m a t i o n of a p h o t o c h e m i c a l l y generated o x i d a n t such as p e r a c e t i c a c i d might be r e s p o n s i b l e f o r the conversion. The a b i l i t y of r e l a t i v e l y i n v o l a t i l e o x i d a n t s t o b r i n g about such r e a c t i o n s was suggested by experiments i n s t e r i l i z e d water obtained from r i c e paddies. I t appeared unl i k e l y i n t h i s case t h a t v o l a t i l e compounds would remain a f t e r vacuum evaporation; n e v e r t h e l e s s 25% of the a l d r i n was converted to d i e l d r i n i n 36 hours i r r a d i a t i o n . The e f f e c t of p h y s i c a l s t a t e has a l s o been s t u d i e d t o some extent. The i n t e r a c t i o n of a molecule w i t h a s u r f a c e m o d i f i e s the p h y s i c a l and chemical p r o p e r t i e s of the molecule through the e f f e c t s of p o l a r o r nonpolar groups a t the i n t e r f a c e . I f the molecule i s i r r a d i a t e d , i t w i l l d i s p l a y m o d i f i e d photochemical behavior because the energy r e l a t i o n s between e x c i t e d e l e c t r o n i c s t a t e s w i l l have been changed. As examples, the u l t r a v i o l e t s p e c t r a of a n i l i n e s and phenols i n hexane were measured i n the presence and absence of s i l i c a . The s h i f t s i n a b s o r p t i o n maxima can be r a t i o n a l i z e d i n terms of hydrogen bonding (11). The changes i n a b s o r p t i o n spectrum produced when a molecule i s adsorbed on a s o l i d w i l l a l s o change i t s |hotochemical b e h a v i o r .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

18

DISPOSAL AND DECONTAMINATION OF PESTTCTDES

S o i l appears to e x e r t a p r o t e c t i v e e f f e c t , but s i l i c a may en­ hance p h o t o l y s i s . Korte and h i s coworkers (12,13) r e p o r t e d the m i n e r a l i z a t i o n of a number of compounds exposed t o u l t r a v i o l e t i r r a d i a t i o n i n an oxygen stream. The source of l i g h t was a h i g h pressure lamp (125 W) housed i n a pyrex c o l d f i n g e r . I t was found t h a t the r a t e of c o n v e r s i o n was g r e a t e r i f the compounds were adsorbed on p a r t i c u l a t e matter than i f they were deposited as s o l i d s or t h i n f i l m s . The experimental arrangement permitted i r r a d i a t i o n of the m a t e r i a l adsorbed on s i l i c a g e l ; the s i l i c a g e l was mixed c o n t i n u o u s l y by a r o t a t i n g drum surrounding the lamp housing. I n i t i a l l y , i t was found t h a t c e r t a i n c y c l o d i e n e p e s t i c i d e s and t h e i r pho t ο i somer i ζ a t ion products were completely decomposed (12) on i r r a d i a t i o n i n the s o l i d s t a t e . Hexachlorobenzene, pentachlorobenzene, pentachlorophenol chlorophenyl)ethane (DDT) ethylene (DDE), 2,2^4,4',5,5'-hexachlorobiphenyl, and 2,2 ,4,5 t e t r a c h l o r o b i p h e n y l were adsorbed on quartz and i r r a d i a t e d (Table I ) . ,

t

Table I . I r r a d i a t i o n of pentachlorophenol, DDT and DDE on 100 g s i l i c a g e l (wavelength > 290 nm) (12).

Compound PCP DDT DDE *

Initial Quantity mg 102 385 362

Amount Recovered 7 days 4 days % mg me % 26 298 91

25 77 25

12 66 19

12 255 69

* A l s o detected dichlorobenzophenone, 38 trichlorobenzophenone, 7 mg

mg;

The r a t e of disappearance o f the compounds was measured, and i n some cases the q u a n t i t y o f CO- and HC1 evolved was a l s o determined. I t was considered t h a t the r a t e o f disappearance was not accounted f o r by the f o r m a t i o n of o r g a n i c photoproducts, nor could i t be a t t r i b u t e d to v o l a t i l i z a t i o n . These f i n d i n g s may have an important b e a r i n g on the f a t e of p e s t i c i d e s adsorbed on p a r t i c u l a t e matter. What Products are Formed i n Photochemical Reactions of P e s t i c i d e s ? In p r a c t i c e , we are concerned w i t h the r a t e of pho to decom­ p o s i t i o n and a l s o w i t h the n a t u r e of the products. P h o t o l y s i s of halogenated compounds o f t e n leads to dehalogenated p r o d u c t s , presumably v i a a process of hydrogen a b s t r a c t i o n from the s o l v e n t by a completely d i s s o c i a t e d molecule or e x c i t e d complex

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2.

19

Decontamination or Disposal of Pesticides

PLIMMER

between s o l u t e and s o l v e n t . The t a b l e s show some r e s u l t s o f our own i n v e s t i g a t i o n s o f the p h o t o l y s i s of s e v e r a l c h l o r i n a t e d aromatic compounds (14,15) (Tables I I - V ) . Table I I . P h o t o l y s i s of chlorophenol methyl ethers i n methanol ( l g / L , wavelength > 260 nm) (14,15). Recovery of C I C ^ O C ^ Time

Y i e l d of

(%)

4 h 8 h

C^OC^

(%)

2.

m

£

o_

m

£

45 13

+ -

7 +

54 83

54 54

70 76

Table I I I . P h o t o l y s i s o f c h l o r o t o l u e n e s wavelength > 260 nm) (14,15). Recovery of C1C H CH 6

Time

4

3

i n methanol ( l g / L ,

Y i e l d of C ^ C I L j

(%)

£. 4 h 8 h

(%)

m

5

13

+

+

Ε 61 37

o^

m

67 60

61 66

Ε 21 37

Table IV. P h o t o l y s i s o f c h l o r o b e n z o n i t r i l e s i n methanol ( l g / L , wavelength > 260 nm) (14,15). Amount Recovered (%)

Product * (%)

4 h

8 h

4 h

8 h

57

36

27

37

82

80

13

17

2,6-Dichlorobenzonitrile 2-Chlorobenzonitrile

*Formed by l o s s o f 1 C l atom. Table V. P h o t o l y s i s o f chlorobenzoic a c i d s i n methanol (0.5 g/L, wavelength > 260 nm, 8 h i r r a d i a t i o n ) (14,15). Amount Recovered (%)

Y i e l d o f C^COOH (%)

ο

-

100

m

9

52

£

37

60

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

I t i s not easy t o p r e d i c t photochemical r e a c t i v i t y i n terms o f the known e l e c t r o n i c e f f e c t s o f s u b s t i t u e n t groups* The e x c i t e d s t a t e i n halogen l o s s i s probably a s i n g l e t , and l i t t l e informat i o n e x i s t s concerning e l e c t r o n d i s t r i b u t i o n i n t h i s s t a t e . S e v e r a l workers have i n v e s t i g a t e d t h e r a t e s o f f o r m a t i o n and t h e products formed by t h e n u c l e o p h i l i c displacement of halogens and other s u b s t i t u e n t s under t h e i n f l u e n c e o f l i g h t . One o f t h e e a r l i e s t s t u d i e s was concerned w i t h the enhancement o f the r a t e o f replacement o f c h l o r i n e by the h y d r o x y l group of c h l o r a c e t i c a c i d under u l t r a v i o l e t l i g h t — i n v e s t i g a t e d by von E u l e r i n 1916 (16). Crosby (17 , and t h i s Symposium) has d i s c u s s e d examples of p h o t o n u c l e o p h i l i c r e a c t i o n s of p e s t i c i d e s and has c i t e d t h e photodecomposition o f n i t r o f e n , fenaminosulf and o t h e r p e s t i c i d e s i n water among a number o f examples. Because l i g h t f a c i l i t a t e should be extended t o determin r e a c t i o n r a t e s can be put t o p r a c t i c a l use. There i s now a s u b s t a n t i a l volume o f l i t e r a t u r e d e s c r i b i n g the i s o l a t i o n and i d e n t i f i c a t i o n of i r r a d i a t i o n products o f p e s t i c i d e s . Many e a r l i e r s t u d i e s were performed under i l l - d e f i n e d c o n d i t i o n s . Subsequent s t u d i e s were c a r r i e d out t o determine products under "environmental" c o n d i t i o n s , i n order t o p r o v i d e i n f o r m a t i o n f o r r e g u l a t o r y agencies. Other l a b o r a t o r y s t u d i e s o f photochemical r e a c t i o n s o f p e s t i c i d e s were conducted f o r "academic" reasons. However, we r e c o g n i z e that t h e processes are complex. I n i t i a l photochemical r e a c t i o n s y i e l d one or more products t h a t may undergo subsequent photochemical o r thermal reactions„ so a complex m i x t u r e of products r e s u l t s . There may be an accumulation o f p h o t o s t a b l e m a t e r i a l s . I n v e r y d i l u t e s o l u t i o n i n t h e presence o f oxygen i t i s l i k e l y t h a t s u b s t a n t i a l degradation o f t h e molecule w i l l occur. M e c h a n i s t i c o r g a n i c photochemistry i s an i n t e l l e c t u a l l y stimulating pursuit. Unfortunately i t i s s t i l l i n a r e l a t i v e l y p r i m i t i v e s t a t e . To quote from a review by H. E. Zimmerman (18): "Despite the i n c r e a s i n g number of known photochemical r e a c t i o n s the t o t a l number o f w e l l - e s t a b l i s h e d photochemical t r a n s f o r m a t i o n s i s i n f i n i t e s i m a l compared w i t h t h a t i n ground s t a t e chemistry .... f u r t h e r , our understanding o f the f a c t o r s which c o n t r o l photochemical r e a c t i o n s i s s t i l l q u i t e p r i m i t i v e . . . more complex c a l c u l a t i o n s a r e not needed, a new approach i s needed. F i n a l l y , t o t a l l y new methods o f determining photochemical r e a c t i o n mechanisms a r e needed; t h e number i s r e a l l y q u i t e s m a l l when compared w i t h those developed f o r use i n ground s t a t e o r g a n i c chemistry." M e c h a n i s t i c s t u d i e s o f p e s t i c i d e photochemistry a r e sparse; the major e f f o r t has u s u a l l y been t o i s o l a t e and i d e n t i f y photoproducts. T h i s can r e a d i l y be understood i n terms o f immediate o b j e c t i v e s , s i n c e concern t h a t t h e photoproducts may become environmental p o l l u t a n t s o r demonstrate t o x i c i t y has been a major

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2.

PLIMMER

Decontamination or Disposal of Pesticides

21

reason f o r undertaking t h e i r i d e n t i f i c a t i o n . Some i n d i c a t i o n of the q u a l i t a t i v e s i g n i f i c a n c e of these photoproducts may have been obtained, but more p r e c i s e q u a n t i t a t i v e i n f o r m a t i o n has been obtained i n o n l y a few cases. K i n e t i c a n a l y s i s presents an extremely important and comp l e x problem. However, few photochemical s t u d i e s of p e s t i c i d e s have been concerned w i t h the measurement of r e a c t i o n r a t e s . For t h i s reason the work of the EPA group i n Athens, Georgia, has been p a r t i c u l a r l y v a l u a b l e i n e s t a b l i s h i n g a q u a n t i t a t i v e t r e a t ment t h a t a l l o w s p r e d i c t i o n of p h o t o l y s i s r a t e s under s o l a r i r r a d i a t i o n (19). This group has approached the problem of determining the l i f e t i m e of organic p o l l u t a n t s i r r a d i a t e d i n a q u a t i c systems. Dealing w i t h the process of d i r e c t p h o t o l y s i s , they have d e r i v e d mathematical expressions as a b a s i s f o r judgment as to whether s i g n i f i c a n t residue i " p h o t o l y s i s r a t e s " of a number of compounds. ( " P h o t o l y s i s r a t e " here i m p l i e s the p h o t o l y t i c conversion of the s t a r t i n g m a t e r i a l over u n i t time.) S o l a r i n t e n s i t y and the a t t e n u a t i o n of l i g h t i n n a t u r a l waters were used to c a l c u l a t e energy i n p u t s . Quantum y i e l d data and a b s o r p t i o n c o e f f i c i e n t s of the m a t e r i a l i n q u e s t i o n were used i n a computer-based c a l c u l a t i o n of photol y s i s r a t e s . The f i g u r e s shown i n Table VI i n d i c a t e the v a l u e s obtained f o r DDE (19). Table V I . P h o t o l y s i s h a l f - l i f e c a l c u l a t e d f o r DDE near the s u r f a c e of water body (19). Season Spring Summer Fall Winter

Half-life 1.4 days 0.94 2.4 61

These c a l c u l a t i o n s were v e r i f i e d e x p e r i m e n t a l l y f o r d i l u t e s o l u t i o n s . In h i g h c o n c e n t r a t i o n s the computed h a l f - l i v e s are longer as one approaches the s i t u a t i o n i n which a l l the i n c i d e n t l i g h t i s absorbed. The s o l v e n t i s r e s p o n s i b l e f o r some energy a b s o r p t i o n , so h a l f - l i f e i n c r e a s e s w i t h i n c r e a s i n g depth. W i t h i n the range of assumptions, there was reasonable correspondence between e x p e r i m e n t a l l y determined r a t e s and those obtained by computation (+ 30%). Even i n the absence of quantum y i e l d d a t a , minimum h a l f - l i v e s can be c a l c u l a t e d from the a b s o r p t i o n spectrum. Many environmental v a r i a b l e s l i m i t the v a l u e of the comp u t a t i o n . However, i n a w a s t e - d i s p o s a l f a c i l i t y , most of these v a r i a b l e s c o u l d be c o n t r o l l e d . Thus, the data and computations present a b a s i s f o r a f e a s i b i l i t y study, because necessary energy input and p h o t o l y t i c h a l f - l i v e s can be c a l c u l a t e d from data obtained i n the l a b o r a t o r y . T h i s approach m e r i t s a t t e n t i o n ,

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

22

DISPOSAL AND

DECONTAMINATION OF PESTICIDES

and i n i t i a l data must be accumulated t o make f u r t h e r e v a l u a t i o n possible» Costs P r a c t i c a l attempts t o e v a l u a t e the techniques are few. The c o s t f i g u r e s provided are of i n t e r e s t but a r e u s u a l l y out of date. In a r e p o r t i s s u e d by the Atomic Energy Commission, B a l l a n t i n e et a l . (20) d i s c u s s e d the p r a c t i c a l i t y of u s i n g atomic r a d i a t i o n f o r wastewater treatment. The a p p l i c a t i o n s t h a t they suggested were the improvement of sludge h a n d l i n g , t o t a l d e s t r u c t i o n of o r g a n i c s , d i s i n f e c t i o n , and the s e l e c t i v e removal of r e f r a c t o r i e s or s p e c i f i c compounds. The l a s t a p p l i c a t i o n i s of particular interest i waste water a r e o r g a n i primary treatment. They c o u l d i n c l u d e c h l o r i n a t e d phenol, l i g n i n e , and o t h e r s l o w l y biodegradable compounds. T h e i r c o n c e n t r a t i o n i n m u n i c i p a l wastewaters ranges from 10 PPM t o o c c a s i o n a l h i g h v a l u e s of 100 PPM. In i n d u s t r i a l wastes, h i g h e r v a l u e s a r e encountered. The c a l c u l a t e d c o s t of r a d i a t i o n treatment f o r 1000 g a l l o n c o n t a i n i n g 10 PPM was $0.11; t h i s i n c r e a s e d t o $1.10 i f the c o n c e n t r a t i o n of p o l l u t a n t was 1000 PPM. These c o s t s were based on disappearance of the r e f r a c t o r y compound, not on t o t a l o x i d a t i o n , which must be accomplished by f u r t h e r treatment. The q u e s t i o n of u s i n g u l t r a v i o l e t i r r a d i a t i o n f o r the r e moval of r e f r a c t o r y compounds from water was addressed by B u l l a and Edgerley (21). They found t h a t a l d r i n , d i e l d r i n and e n d r i n i n d i l u t e aqueous s o l u t i o n s were degraded by l i g h t of 253.7 nm wavelength. Time, depth and i n t e n s i t y of r a d i a t i o n were r e l a t e d to the degradation of i n d i v i d u a l compounds, and c o s t estimates were made f o r 50 percent degradation of p e s t i c i d e s a t 10 cm depth. These were $24 f o r a l d r i n s o l u t i o n s , $74 f o r d i e l d r i n and $57 f o r e n d r i n per m i l l i o n g a l l o n s , f o r c o n c e n t r a t i o n s of 20 t o 25 ug per l i t e r . These f i g u r e s c o u l d p o s s i b l y be reduced i f the r e a c t o r design were improved, and many compounds l e s s r e s i s t a n t t o p h o t o l y s i s could be processed a t lower c o s t . I r r a d i a t i o n i n the presence of o x i d a n t s such as c h l o r i n e or oxygen may be more e f f e c t i v e ; however, the f o r m a t i o n of c h l o r i n a t e d o r g a n i c molecules as end products i s u n d e s i r a b l e . There i s need f o r f u r t h e r study of the comparative c o s t s of waste d i s p o s a l by i n c i n e r a t i o n , b i o l o g i c a l treatment, s o i l d i s p o s a l , ocean d i s p o s a l and i r r a d i a t i o n . I n a d d i t i o n to d o l l a r c o s t s , other f a c t o r s , p a r t i c u l a r l y environmental impacts, must a l s o be taken i n t o account. U l t i m a t e l y , i t i s to be hoped t h a t t e c h n o l o g i c a l developments w i l l permit the e f f i c i e n t u t i l i z a t i o n of s o l a r energy to degrade chemical wastes; such a process might i n v o l v e the use of p h o t o l y s i s alone o r as a p r e p a r a t o r y step to achieve p a r t i a l breakdown of r e f r a c t o r y molecules b e f o r e wastes are subjected t o m i c r o b i o l o g i c a l degradation.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2. PLIMMER

Decontamination or Disposal of Pesticides

Literature

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2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

23

Cited

Lawless, E. W., Ferguson, T. L . , and Meiners, A. F. "Guide­ lines for the Disposal of Small Quantities of Unused Pesti­ cides'." EPA-67012-75-057, National Environmental Research Center, U. S. Environmental Protection Agency, Cincinnati, Ohio. 1975. Kennedy, M. V., Stojanovic, B. J., and Shuman, F. L . , Jr., Residue Rev. (1967) 29, 89-104. Plimmer, J. R., and Kearney, P. C. 165th Natl. Mtg. Amer. Chem. Soc., Dallas (April 1973). Kennedy, M. V., Stojanovic, B. J., and Shuman, F. L . , Jr., J. Environ. Qual (1972) 1, 63-65. Peakall, D. Β., and Lincer J. L . BioScienc (1970) 20 958-964. Plimmer, J. R., Klingebiel, U. I., Crosby, D. G., and Wong, A. S. Advances in Chemistry No. 120. pp. 44-54. American Chemical Society, Washington, D.C. 1973. Crosby, D. G., and Wong, A. S., Science (1977) 195, 13371338. Turro, N. J., J. Chem. Ed. (1967) 44, 536-537. Plimmer, J. R., Kearney, P. C., Kaufman, D. D., and Guardia, F. S., J. Agr. Food Chem. (1967) 15, 996-997. Roos, R. D., and Crosby, D. C., Chemosphere (1975) 5, 277282. Plimmer, J. R., in "Fate of Pesticides in Environment", Vol. 6 of "Pesticide Chemistry", A. S. Tahori, ed. pp. 47-76. Gordon and Breach Science Publishers, New York and London. 1972. Gäb, S., Parlar, H., Nitz, S., Hastert, Κ., and Korte, F., Chemosphere (1974) 3, 183-186. Gäb, S., Nitz, Η., Parlar, Η., and Korte, F., Chemosphere (1975) 4, 251-256. Plimmer, J. R., Residue Rev. (1971) 33, 47-74. Plimmer, J. R., and Hummer, Β. Ε., 155th Am. Chem. Soc. Nat. Meeting, San Francisco (1968). von Euler, Η., Chem. Ber. (1916) 49, 1366-1371. Crosby, D. G., Moilanen, K. W., Nakagawa, Μ., and Wong, A. S., U.S.-Japan Seminar on the Environmental Toxicology of Pesticides, Ioso, Japan, Oct. 1971. Zimmerman, Η. Ε., Science (1976) 191, 523-528. Zepp, R. Α., and Clive, D. Μ., Environ. Sci. Technol. (1977) 11, 359-366. Ballantine, D. S., Miller, L. Α., Bishop, D. F., and Rohrman, F. A. Atomic Energy Commission Report. 1970. Bulla, C. D., III, and Edgerley, E., Jr., J. Water Pollut. Contr. Fed. (1968) 40, 546-556.

MARCH 9,

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

3 Catalytic Hydrodechlorination of Polychlorinated Hydrocarbons 1

2

WILMER L. KRANICH, RENEB.LaPIERRE ,LASZLOGUCZI ,and ALVINH.WEISS Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609

Catalytic hydrodechlorination is one of the methods under consideration for conversion of chlorinated pesticides and other environmentally undesirable chlorinated compounds into environmentally acceptable products. LaPierre, Guczi, Wu, Kranich and Weiss (1-3) have reported on the reaction f DDT (and i t derivativ b simple dehydrochlorination typical polychlorinated biphenyl). Both liquid and gas phase reactions were studied over a range of pressures from 1 to 50 bar, temperatures from 20 to 230°C and with both nickel and palladium catalysts. Solvents for liquid phase reactions included ethanol and xylene, and both calcium and sodium hydroxides were used as hydrochloric acid (by-product) acceptors. In this paper additional hydrodechlorination data are given for Dieldrin, Aldrin, and Toxaphene (chlorinated camphene). Chemistry of Hydrodechlorination PCB. The catalyzed hydrodechlorination reactions to remove chlorine from PCBs proceed one step at a time in a consecutive manner. ØØ represents a biphenyl nucleus substituted with n chlorine atoms 54

~43

32 +H

~21 +H„

00 5 -HC1» 00, -HC1 » 00, -HC1 » 00. -HC1 *

~10 —» 00 1 -HC1 9

00 ο

K i n e t i c s are w e l l represented by a s e r i e s o f successive reactions. I f s i m p l e f i r s t o r d e r r a t e c o n s t a n t s (^ ) a r e calculated r e l a t i v e t o the f i r s t step, a single set o f c o n s t a n t s r e p r e s e n t s t h e d a t a o v e r t h e r a n g e o f 60-130°C at 50 b a r h y d r o g e n p r e s s u r e f o r l i q u i d - p h a s e r e a c t i o n s mn

1

Current address: Mobil Research Corporation, Princeton, Ν J Current address: Institute of Isotopes, Hungarian Academy of Sciences, Budapest, Hungary 2

0-8412-0433-0/78/47^73-024$05.00/0 © 1978 A m e r i c a n C h e m i c a l Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

3.

KRANICH ET AL.

Polychlorinated Hydrocarbons

25

i n e t h a n o l s o l v e n t w i t h n i c k e l c a t a l y s t ( G i r d l e r G49) and NaOH as a c i d a c c e p t o r . P r o d u c t d i s t r i b u t i o n s b a s e d on k =1, k =0.40, k = 0 . 2 3 , k =0.36, and k =0.40 a r e snown i n F i g u r e 1 superimposée on t h e e x p e r i m e n t a l d a t a . DDT-DDE. I n t h e p r e s e n c e o f sodium h y d r o x i d e i n e t h a n o l s o l v e n t , DDT i s q u i c k l y c o n v e r t e d n o n - c a t a l y t i c a l l y t o DDE. 3 2

C10

HC1

¥

- C - 0C1 I

cci (DDT)

3

- >

C10

0C1

- C Μ

cci

2

(DDE)

The subsequent r e a c t i o n not o n l y i n v o l v e c o n s e c u t i v but a l s o p a r a l l e l r e a c t i o n s i n which o l e f i n i c c h l o r i n e s a r e removed and t h e a s s o c i a t e d o l e f i n i s s a t u r a t e d w i t h o u t i n t e r m e d i a t e d e s o r p t i o n from the c a t a l y s t . Note i n the f o l l o w i n g r e a c t i o n n e t w o r k t h a t as many as f i v e h y d r o g e n m o l e c u l e s r e a c t i n one s t e p . The numbers shown are f i r s t order r a t e c o n s t a n t s r e l a t i v e t o the t o t a l r a t e o f r e a c t i o n o f DDE by a l l f o u r p a t h s , f o r l i q u i d phase r e ­ a c t i o n w i t h h y d r o g e n a t 50 b a r , N i c a t a l y s t , o v e r t h e temp­ e r a t u r e r a n g e 20-100°C. These c o n s t a n t s have b e e n used t o c a l c u l a t e t h e p r o d u c t d i s t r i b u t i o n shown i n F i g u r e 2, s u p e r i m p o s e d on t h e e x p e r i m e n t a l d a t a .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

AROCLOR

HYDRODECHLORINATION

Fraction Chlorine Unconverted Figure 1. Product distribution conversion for hydrodechlorination chrl248)

vs. chlorine of PC Β (Aro-

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

3.

KRANiCH ET AL.

ΡOlychlorinated Hydrocarbons

Figure 2. Product distribution version for hydrodechlorination

vs. chlorine con­ of DDE (DDT)

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

27

28

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Aldrin-Dieldrin. The s t r u c t u r e s corresponding epoxide D i e l d r i n a r e :

o f A l d r i n and i t s

Dieldrin

Aldrin

E x p e r i m e n t a l d a t a o n r e l a t i v e mole f r a c t i o n o f h y d r o dechlorination product i n F i g u r e s 3 and 4. a c t i o n i n e t h a n o l a t 50 b a r h y d r o g e n and 130°C w i t h NaOH as a c i d a c c e p t o r . The c a t a l y s t i s a g a i n n i c k e l ( G i r d l e r G49). Experimental procedures a r e s i m i l a r t o those desc r i b e d f o r DDE (2) and A r o c l o r 1248 ( 3 ) . The d a t a do n o t lend themselves t o simple k i n e t i c a n a l y s i s . For A l d r i n , h y d r o d e c h l o r i n a t i o n appears t o proceed as follows: + H C

H

12 8

C 1

6

C

-HCl

H

12 11

C 1

5

-HCl

C

H

12 12

\+3H

2 2HC1

V

V H

12 15

C 1

4

Y+3H

2 2HC1

C

C 1

C

3

H

12 16

C 1

2

F i r s t an o l e f i n i c group i n A l d r i n hydrogenates (the epoxide i n D i e l d r i n i s not a f f e c t e d a t these c o n d i t i o n s ) i n a step simultaneous w i t h removal o f a h i g h l y a c t i v e geminal d i chloride. The m o l e c u l e t h e n l o s e s i n one s t e p i t s o l e f i n i c c h l o r i n e atoms and h y d r o g e n a t e s t h a t o l e f i n i c bond. F o r D i e l d r i n t h e p r i n c i p a l r e a c t i o n p a t h seems t o b e s i m i l a r b u t s i m p l e r , s i n c e t h e r e i s no o l e f i n i c bond t o hydrogenate. +H C

H

12 8

C 1

6°

+H

2

-HCÏ*

C

H

12 9

C 1

5°

-HCl

C

H

C 1

12 10 4°

The l a s t h i g h l y u n r e a c t i v e c h l o r i n e s t o b e removed a r e t h e a l i p h a t i c c h l o r i n e s , and t h e c o n s e q u e n c e o f t h e i r v e r y l o w r e a c t i v i t y i s t h a t A l d r i n and D i e l d r i n a r e n o t r e a d i l y completely s t r i p p e d t o t h e corresponding hydrocarbon skeletons.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

KRANiCH ET AL. 1.0 ι

Polychlorinated Hydrocarbons 1

1

1

1 I I I II

1

Reaction Time

(Min.)

1

1

1—I I I I

Figure 3. Distribution of hydrodechlorination products of Aldrin vs. reaction time

10

too Reaction Time

Figure

4.

ιροο

ιοροο

(Min.)

Distribution of hydrodechlorination Dieldrin vs. reaction time

products of

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

30

DISPOSAL AND

DECONTAMINATION OF PESTICIDES

Toxaphene. Toxaphene i s a m i x t u r e o f h i g h l y c h l o r i n a t e d d e r i v a t i v e s o f camphene. A t y p i c a l compound w h i c h has been i s o l a t e d from a r e p r e s e n t a t i v e toxaphene m i x t u r e i s a heptachlorobornane. Ci

In h y d r o d e c h l o r i n a t i o n the geminal c h l o r i n e s a r e r e a d i l y a t t a c k e d but the remaining a l i p h a t i c c h l o r i n e s are q u i t e s t a b l e . As w i t h D i e l d r i n and A l d r i n , c o m p l e t e r e moval o f c h l o r i n e f r o m t h e h y d r o c a r b o n s k e l e t o n i s v e r y difficult. Experimenta c h l o r i n a t i o n are give TABLE I TOXAPHENE HYDRODECHLORINATION AT 100°C, 50 BAR (4-6 wt % Toxaphene i n E t h a n o l ; lOgm Toxaphene/gm c a t a l y s t ^ N i on K i e s e l g u h r ) R e a c t i o n Time ( h r ) 2 4 19 C h l o r i n e atoms/molecule D i s t r i b u t i o n (%) 0 16.5 32.4 37.2 1 21.4 29.0 25.8 2 29.9 20.3 24.2 3 9.4 2.8 1.2 4 8.5 11.6 10.5 5 5.5 2.0 1.1 6 6.1 1.9 7 1.5 8 1.2 Based on i t s 68% (wt) c h l o r i n e , t h e o r i g i n a l Toxaphene c o n t a i n e d an a v e r a g e o f 7.8 c h l o r i n e atoms p e r m o l e c u l e Hydrodechlorination Process. A process i s proposed b a s e d on t h e l a b o r a t o r y s t u d i e s , w h i c h i s c a p a b l e o f dec h l o r i n a t i n g DDT and PCBs t o any d e s i r e d l e v e l and p a r t i a l l y d e c h l o r i n a t i n g D i e l d r i n , A l d r i n and Toxaphene. A c o n c e p t u a l i z e d f l o w s h e e t i s g i v e n i n F i g u r e 5. The m a t e r i a l s t o be t r e a t e d a r e c h a r g e d as a b a t c h t o a r o t a r y ( t u m b l i n g ) e x t r a c t o r . The o r g a n i c m a t e r i a l s t o be h y d r o d e c h l o r i n a t e d a r e e x t r a c t e d w i t h hot e t h a n o l and pumped t o t h e r e a c t o r . D u r i n g t h e e x t r a c t i o n phase t h e r e a c t o r c o n t e n t s a r e b o i l e d a t a t m o s p h e r i c p r e s s u r e and t h e e t h a n o l i s e v a p o r a t e d , condensed and r e t u r n e d t o t h e e x t r a c t o r u n t i l t h e c o n t a i n e r s and i n e r t m a t e r i a l s r e m a i n i n g i n t h e e x t r a c t o r a r e f r e e o f p e s t i c i d e s . E t h a n o l may be r e c o v e r e d f r o m t h e c l e a n e d s o l i d w a s t e e i t h e r by a f i n a l e x t r a c t i o n w i t h w a t e r o r by h e a t i n g s u f f i c i e n t l y t o

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

KRANICH ET AL.

Polychlorinated

Hydrocarbons

Figure 5. Hydrodechlorination process flow diagram

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

31

32

DISPOSAL AND DECONTAMINATION OF PESTICIDES

flash i t off. Sodium h y d r o x i d e ( d i s s o l v e d i n e t h a n o l ) i s t h e n added t o t h e r e a c t o r and t h e s y s t e m i s p r e s s u r i z e d w i t h h y d r o g e n . Hydrodechlorination proceeds i n t h e presence o f t h e n i c k e l c a t a l y s t , which i s r e t a i n e d i n t h e r e a c t o r from b a t c h t o batch. NaOH s o l u t i o n i s added a u t o m a t i c a l l y i n r e s p o n s e to decreasing a l k a l i n i t y o f t h e reacting s o l u t i o n . When t h e r e a c t i o n r e a c h e s t h e d e s i r e d d e g r e e o f comp l e t i o n as i n d i c a t e d b y t h e demand f o r NaOH s o l u t i o n , t h e l i q u i d contents a r e s t r a i n e d through t h e c a t a l y s t r e t e n t i o n screen t o t h e solvent recovery s t i l l . Here some o r a l l o f t h e e t h a n o l i s b o i l e d o f f , p u r i f i e d i n a column a s n e c e s s a r y t o remove w a t e r o r o t h e r i m p u r i t i e s and r e t u r n e d t o t h e solvent holding tank. The p r o d u c t s c o n t a i n i n NaOH a r e e x t r a c t e d w i t ganics. Use o r d i s p o s a l o f t h e o r g a n i c p r o d u c t s depends on t h e d e g r e e o f d e c h l o r i n a t i o n , c o m p l e x i t y o f t h e f e e d and p r o d u c t , and t h e u s e f u l n e s s o f t h e p r o d u c t f o r o t h e r p u r p o s e s ( e . g . a s a p l a s t i c i z e r o r c h e m i c a l raw m a t e r i a l ) . Reactor Design. Laboratory r e s u l t s permit estimation o f t h e r e a c t i o n time r e q u i r e d t o reach a g i v e n degree o f c h l o r i n e r e m o v a l and t h e d i s t r i b u t i o n o f p r o d u c t s . F o r r e a c t i o n s a t 100°C, 50 b a r p r e s s u r e , 6 1 % N i o n k i e s e l g u h r c a t a l y s t , 1-6% ( w e i g h t ) r e a c t a n t i n e t h a n o l , 10-40 grams r e a c t a n t p e r gram c a t a l y s t , t h e p e r c e n t a g e o f o r i g i n a l c h l o r i n e r e m a i n i n g as a f u n c t i o n o f t i m e i s g i v e n a p p r o x i m a t e l y b y F i g u r e 6 f o r DDE, PCB ( A r o c l o r 1248) and Toxaphene. D i e l d r i n - A l d r i n d a t a a r e n o t i n c l u d e d , s i n c e t h e i r h y d r o d e c h l o r i n a t i o n s were r u n a t 130°C. A l l o f t h e c u r v e s show r a p i d i n i t i a l r e p l a c e m e n t o f some o f t h e c h l o r i n e b y h y d r o g e n f o l l o w e d b y s l o w e r r e a c t i o n . Since s e v e r a l types o f c h l o r i n e bonding e x i s t , t h e more l a b i l e t y p e s ( a r o m a t i c , o l e f i n i c , g e m i n a l ) a r e attacked before the very s t a b l e a l i p h a t i c c h l o r i n e s . W i t h D i e l d r i n and A l d r i n , i n i t i a l r e a c t i o n o f g e m i n a l c h l o r i n e s i s r a p i d , b u t a l i p h a t i c monochloro bonds a r e o n l y very s l o w l y s u b s t i t u t e d by hydrogen. I f f u r t h e r c h l o r i n e r e m o v a l f r o m t h e s e compounds i s r e q u i r e d ( r a t h e r t h a n s i m p l y t h e r e d u c t i o n i n t o x i c i t y accompanying t h e r a p i d i n i t i a l r e a c t i o n ) , more s e v e r e o p e r a t i n g c o n d i t i o n s w o u l d b e needed. Figure 2 follows i n d e t a i l the intermediate reaction p r o d u c t s c o n t a i n i n g t h e i n d i c a t e d number o f c h l o r i n e atoms per m o l e c u l e as a f u n c t i o n o f t h e f r a c t i o n t o t a l c h l o r i n e removed f r o m DDE. F i g u r e 1 g i v e s t h e same i n f o r m a t i o n f o r A r o c l o r 1248, a t y p i c a l p o l y c h l o r i n a t e d b i p h e n y l . Both o f these s e t s o f curves a r e n e a r l y independent o f temperature. F i g u r e s 1, 2, and 6 c a n be t r e a t e d a s d e s i g n c u r v e s t o meet a v a r i e t y o f p r o c e s s i n g o b j e c t i v e s f o r t h e s e two

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Polychlorinated

3. KRANiCH ET AL.

33

\

Ό Φ φ c ο υ c

Hydrocarbons

0.8

Ζ> φ

Ë

0.6

Ο

JC ο ο c

]

!

α» 0.4 Ο Ο c ο

'Ζ 0.2

DDE \

^

Ν 5

TOXAPHEN Ε

I —.^L.

PCB

ι

10

15

20

Reaction Time, Hrs.

Figure 6. Chlorine conversion vs. time (liquidphase hydrodechlorination at 100°C, 50 bar, 16% (wt) in ethanol, 10-40 g reactant/g 61% Ni on kieselguhr catalyst)

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

34

m a t e r i a l s s u c h a s removal o f a g i v e n f r a c t i o n o f o r i g i n a l c h l o r i n e , c o n v e r s i o n o f a g i v e n f r a c t i o n o f s t a r t i n g mat­ e r i a l , o r maximizing t h e y i e l d o f a p a r t i c u l a r i n t e r m e d i a t e . Acknowledgement F i n a n c i a l s u p p o r t f o r t h i s s t u d y was p r o v i d e d b y t h e U n i t e d S t a t e s E n v i r o n m e n t a l P r o t e c t i o n Agency under EPA c o n t r a c t R 802-857-01 " C a t a l y t i c C o n v e r s i o n o f H a z a r d o u s and T o x i c C h e m i c a l s " . D r . E. B i r o n h e l p e d i n t h e work.

Abstract A conceptual process i s described for the c a t a l y t i c hydrodechlorination o A l d r i n , D i e l d r i n , an undesirable compounds (e.g. polychlorinated biphenyls, PCB). Experimental studies show that chlorines can i n general be c a t a l y t i c a l l y replaced by hydrogen to any desired extent. Products are generally high boiling o i l s which may be use­ ful or readily burned. Reaction models are proposed and relative rate con­ stants determined for several hydrodechlorinations. In general, o l e f i n i c and aromatic chlorines are more easily removed than aliphatic chlorines. Highly bridged, non­ -planar molecules l i k e Dieldrin and A l d r i n are very d i f f ­ i c u l t to hydrodechlorinate completely.

Literature Cited 1) LaPierre, R.B., Wu, D., Kranich, W.L., and Weiss, A.H. J . Catal., (1978), (In Press) 2) LaPierre, R.B., Guczi, L., Kranich, W.L., and Weiss, A.H., J . Catal. (1978), (Paper on DDE - In Press) 3) LaPierre, R.B., Guczi, L., Kranich, W.L., and Weiss, A.H., J . Catal. (1978), (Paper on PCB - In Press) See Also: LaPierre, R.B., Biron, Ε., Wu, D., Guczi, L., Kranich, W.L., and Weiss, A.H., "Catalytic Conversion of Hazardous and Toxic Chemicals: Pesticides and Related Substances," Document No. PB 262 804, EPA600/3-77-018, January 1977. National Technical In­ formation Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Va. See also "Catalytic Hydrodechlorination of Polychlorinated Pesticides and Related Substances: An Executive Summary," EPA-600/ 8-77-013, September 1977. MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

34

m a t e r i a l s s u c h a s removal o f a g i v e n f r a c t i o n o f o r i g i n a l c h l o r i n e , c o n v e r s i o n o f a g i v e n f r a c t i o n o f s t a r t i n g mat­ e r i a l , o r maximizing t h e y i e l d o f a p a r t i c u l a r i n t e r m e d i a t e . Acknowledgement F i n a n c i a l s u p p o r t f o r t h i s s t u d y was p r o v i d e d b y t h e U n i t e d S t a t e s E n v i r o n m e n t a l P r o t e c t i o n Agency under EPA c o n t r a c t R 802-857-01 " C a t a l y t i c C o n v e r s i o n o f H a z a r d o u s and T o x i c C h e m i c a l s " . D r . E. B i r o n h e l p e d i n t h e work.

Abstract A conceptual process i s described for the c a t a l y t i c hydrodechlorination o A l d r i n , D i e l d r i n , an undesirable compounds (e.g. polychlorinated biphenyls, PCB). Experimental studies show that chlorines can i n general be c a t a l y t i c a l l y replaced by hydrogen to any desired extent. Products are generally high boiling o i l s which may be use­ ful or readily burned. Reaction models are proposed and relative rate con­ stants determined for several hydrodechlorinations. In general, o l e f i n i c and aromatic chlorines are more easily removed than aliphatic chlorines. Highly bridged, non­ -planar molecules l i k e Dieldrin and A l d r i n are very d i f f ­ i c u l t to hydrodechlorinate completely.

Literature Cited 1) LaPierre, R.B., Wu, D., Kranich, W.L., and Weiss, A.H. J . Catal., (1978), (In Press) 2) LaPierre, R.B., Guczi, L., Kranich, W.L., and Weiss, A.H., J . Catal. (1978), (Paper on DDE - In Press) 3) LaPierre, R.B., Guczi, L., Kranich, W.L., and Weiss, A.H., J . Catal. (1978), (Paper on PCB - In Press) See Also: LaPierre, R.B., Biron, Ε., Wu, D., Guczi, L., Kranich, W.L., and Weiss, A.H., "Catalytic Conversion of Hazardous and Toxic Chemicals: Pesticides and Related Substances," Document No. PB 262 804, EPA600/3-77-018, January 1977. National Technical In­ formation Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Va. See also "Catalytic Hydrodechlorination of Polychlorinated Pesticides and Related Substances: An Executive Summary," EPA-600/ 8-77-013, September 1977. MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4 Photodegradation of Halogenated Xanthene Dyes JAMES R. HEITZ Department of Biochemistry, Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Mississippi State, MS 39762 W. W. WILSON Department of Chemistry, Mississipp At the outset, the work of several other of our colleagues who aided in the collection of the data used in this presenta­ tion should be acknowledged. They are Dr. Gajanan Pimprikar, Mr. Richard D. Vincent, Mr. John E. Fondren, Jr., Mr. William A. Peoples, II, and Mr. Kashinath Nag--all of Mississippi State University. Since this symposium is devoted to "Disposal and Decontam­ ination of Pesticides," it is appropriate to justify the inclu­ sion of xanthene dyes as pesticides before discussing our work on the degradation and detoxification of these molecules. Within the last six years, i t has been reported that when insects were fed certain dyes and subsequently exposed to visible light, a toxic reaction was observed (1-10). An example of this toxicity in insects caused by the synergistic effects of visi­ ble light and dyes is shown in Table I. Imported fire ants were field collected and maintained in the mound soil in the labora­ tory on a water diet for seven days. After that time, approxi­ mately 100 specimens were put into glass petri dishes. A piece of wet filter paper provided moisture. Aqueous sucrose solu­ tions, to which variable amounts of rose bengal had been added, were placed in plastic cups containing a small piece of cotton dental wicking. This served as the food source as well as the means of administering the dye to the insects. After incubating the fire ants in the petri dishes for 24 hours, they were exposed to 3800μW/cm visible light from two 40W General Electric cool white fluorescent lamps. This is approximately 10 percent of the light available on a sunny day. The data are presented as percent mortality ± one standard deviation at 1, 2, 3, 4, and 6 hrs of light exposure at four rose bengal concentrations ranging from 4.9 x 10 M down to 4.9 x 10 M. There is an inverse relationship between the feeding concentration and the LT value as well as the time of light exposure and the LD value. Later studies have shown that it is a superior technique to present the insect mortality data as a function not only of the 2

-3

-4

50

50

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

30.5 (±16.4)

7.4 (±4.9)

3.7 (±2.6)

2.46

0.98

0.49 6.1 (±3.6)

14.5 (±7.1)

45.1 (±21.8)

64.7 (±9.2)

13.6 (±7.9)

23.6 (±4.3)

59.8 (±29.3)

88.7 (±8.9)

23.8 (±14.4)

34.3 (±7.0)

73.6 (±17.7)

94.8 (±3.7)

Exposure Time ( h r ) * 2 3 4

44.4 (±20.6)

60.7 (±7.4)

89.0 (±14.8)

99.7 (±0.7)

6

50

7.0

5.2

2.4

0.7

L T

b

.97

.98

.99

.90

r

5 0

1

LD c 5.5 3.5 (10-3 M) 2.5 1.8 0.24 r .96 .97 .98 .96 9 ^Data presented as percent mean m o r t a l i t y ± one standard d e v i a t i o n , d e t e r m i n e d by l i n e a r r e g r e s s i o n o f m o r t a l i t y data a t a known dose l e v e l . CDetermined by l i n e a r r e g r e s s i o n o f m o r t a l i t y data d u r i n g a known time i n t e r v a l . (Reproduced from Reference 3.)

42.1 (±7.6)

1

4.90

Rose Bengal (10-3 M )

M o r t a l i t y o f the Imported F i r e Ant as a F u n c t i o n o f Dye C o n c e n t r a t i o n and Time

Table I

4.

ΗΕΓΤΖ AND WILSON

Halogenated Xanthene Dyes

37

d i e t a r y dye c o n c e n t r a t i o n ; b u t a l s o as a f u n c t i o n o f t h e t i s s u e dye l e v e l . The f i r s t t o x i c r e a c t i o n i n v o l v e d t h e s y n e r g i s t i c e f f e c t o f v i s i b l e l i g h t and dyes on t h e i n s e c t . A second dye induced t o x i c r e a c t i o n i n i n s e c t s was discovered i n our l a b o r a t o r y which occurred i n t h e absence o f l i g h t and was c o n s i d e r a b l y slower than t h e p r e v i o u s l y discussed l i g h t - c a t a l y z e d r e a c t i o n . Figure 1 shows the p r o b i t m o r t a l i t y f o r three i n s e c t species exposed t o a 5 χ 10"3M rose bengal food source i n t h e absence o f l i g h t . P r o b i t s a r e merely a l i n e a r t r a n s f o r m a t i o n o f the sigmoidal death curve. The feeding medium f o r t h e b o l l w e e v i l (X) was an a r t i f i c i a l d i e t e s s e n t i a l l y developed by L i n d i g and Malone (11). A one percent sucrose s o l u t i o n was used f o r the imported f i r e a n t (0). A two percent m i l k - s u c r o s e s o l u t i o n was used f o r the house f l y (·). P r e l i m i n a r that the s u s c e p t i b i l i t the house f l y . There appears t o be a wide divergence i n t h e s u s c e p t i b i l i t y o f d i f f e r e n t species o f i n s e c t t o t h e l i g h t independent t o x i c mechanism. The mechanism which appears t o be o p e r a t i v e i n the l i g h t c a t a l y z e d r e a c t i o n i s shown i n F i g u r e 2. The dye i n the ground s i n g l e t s t a t e absorbs a photon o f v i s i b l e l i g h t (a) and i s e x c i t e d t o some higher s i n g l e t s t a t e . I f the dye was r a i s e d t o the second e x c i t e d s i n g l e t s t a t e o r some higher s t a t e , i t would g i v e o f f the excess energy as heat (h) and decay t o the f i r s t e x c i t e d s i n g l e t s t a t e . The l i f e t i m e o f t h e f i r s t e x c i t e d s i n g l e t s t a t e i s on the order o f nanoseconds· There a r e three main f a t e s o f t h e dye molecule i n t h i s s t a t e : 1) i t may g i v e o f f the excess energy as heat (h) and r e t u r n t o t h e ground s i n g l e t s t a t e ; 2) i t may g i v e o f f the excess energy as l i g h t ( f ) and r e t u r n t o the ground s i n g l e t s t a t e — t h i s i s d e f i n e d as fluorescence; 3) i t may go from a s i n g l e t s t a t e t o a t r i p l e t s t a t e by i n v e r t i n g the s p i n o f an e l e c t r o n — t h i s i s c a l l e d i n t e r s y s t e m c r o s s i n g . I f t h e dye moves t o t h e t r i p l e t s t a t e by intersystem c r o s s i n g , i t has reached a more s t a b l e s t a t e w i t h a l i f e t i m e greater than microseconds. I f one ignores t h e r e v e r s e intersystem c r o s s i n g back t o the f i r s t e x c i t e d s i n g l e t s t a t e , there a r e three main f a t e s o f t h e dye molecule i n t h i s s t a t e : 1) i t may g i v e o f f the excess energy as heat (h) and r e t u r n t o the ground s i n g l e t s t a t e ; 2) i t may g i v e o f f t h e energy as l i g h t (p) and r e t u r n t o t h e ground s i n g l e t s t a t e — t h i s i s d e f i n e d as phosphorescence; 3) i t may g i v e the energy t o a second molecule, i n t h i s case, oxygen. The dye thereby r e t u r n s t o t h e ground s i n g l e t s t a t e and the oxygen i s r a i s e d t o the f i r s t e x c i t e d s t a t e . T h i s use o f t h e dye molecule t o absorb l i g h t energy and t r a n s f e r i t t o oxygen t o form the very r e a c t i v e and t o x i c s i n g l e t oxygen i s i n t e g r a l to d y e - s e n s i t i z e d p h o t o o x i d a t i o n and probably t o t h e dye-induced t o x i c i t y o f v i s i b l e l i g h t i n i n s e c t s . Since movement o f t h e s i n g l e t dye t o t h e t r i p l e t dye i s c r i t i c a l to the t o x i c r e a c t i o n , t h e more phosphorescent t h e dye i s , the

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

38

DISPOSAL AND DECONTAMINATION OF PESTÏODES

more t o x i c i t should be. W i t h i n t h e xanthene s e r i e s o f dyes, t h i s has been observed. Decreasing t o x i c i t y g e n e r a l l y corresponds w i t h decreasing halogen content. F i g u r e 3 shows t h e s t r u c t u r e o f the xanthene dyes most s t u d i e d t o date. Rose bengal, t h e b e s t s e n s i t i z e r t o date i n a l l cases, c o n t a i n s i o d i n e a t A and c h l o r i n e a t B. P h l o x i n B, c u r r e n t l y being t e s t e d on t h e imported f i r e ant, c o n t a i n s bromine a t A and c h l o r i n e a t B. E r y t h r o s i n B, c u r r e n t l y under t e s t w i t h two Musca s p e c i e s , c o n t a i n s i o d i n e a t A and hydrogen a t B. E o s i n y e l l o w i s h c o n t a i n s bromine a t A and hydrogen a t B. The two dyes shown i n e f f e c t i v e i n every study t o date a r e f l u o r e s c e i n , c o n t a i n i n g hydrogen a t both A and Β and rhodamine B, c o n t a i n i n g hydrogen a t A and Β and w i t h two wing oxygens r e p l a c e d by d i e t h y l a m i n o groups. T h i s i n s p e c t i o n o f the dye s t r u c t u r e s a l s o may serve t o e x p l a i n t h e observe and l i g h t - i n d e p e n d e n t mechanisms may i n c r e a s e t h e t o x i c i t y o f t h e light-dependent mechanism by i n c r e a s i n g t h e t r i p l e t s t a t e p o p u l a t i o n s . Increased halogen content may i n c r e a s e the t o x i c i t y o f t h e l i g h t - i n d e p e n d e n t mechanism s i m i l a r t o an o r g a n o c h l o r i n e mechanism. There would be two e n t i r e l y d i f f e r e n t mechanisms, b u t i n e x t r i c a b l y l i n k e d together through the halogen content o f t h e dye molecules themselves. Having shown t h e p e s t i c i d a l p o t e n t i a l o f t h e xanthene dyes, i t now becomes important t o i n v e s t i g a t e t h e degradation o f t h e dyes once they a r e i n t r o d u c e d i n t o t h e environment. When n i t r o g e n gas was bubbled through a rose bengal s o l u t i o n t o decrease as f a r as p o s s i b l e t h e oxygen c o n c e n t r a t i o n i n the s o l u t i o n , then s e a l e d and p l a c e d i n s u n l i g h t f o r two months, a s t r a w - c o l o r e d s o l u t i o n was generated. I f t h e rose bengal s o l u t i o n was n o t deoxygenated and was i n s t e a d l e f t open t o t h e environment and f u l l s u n l i g h t f o r two months, a c l e a r s o l u t i o n was generated. The i n c r e a s e d a v a i l a b i l i t y o f oxygen i n t h e l a t t e r case probably f a c i l i t a t e d t h e d e c o l o r i z a t i o n r e a c t i o n . The e x t e n t o f the d e c o l o r i z a t i o n i s shown i n F i g u r e 4. The v i s i b l e a b s o r p t i o n spectrum o f rose bengal between 400nm and 600nm i s d e p i c t e d by curve B. Upon photodegradation, the a b s o r p t i o n disappears completely (curve A ) . A t t h i s p o i n t t h e q u e s t i o n remained as t o t h e complexity o f the photodegradation r e a c t i o n . A f t e r a p a r t i a l l y complete photodegradation r e a c t i o n h i g h performance l i q u i d chromatography was used t o i n v e s t i g a t e the composition o f the s o l u t i o n . F i g u r e 5 shows pure rose bengal on t h e l e f t and t h e p a r t i a l l y degraded rose bengal on the r i g h t . These t r a c e s , and t h e ones t h a t f o l l o w , were generated u s i n g a Waters M6000A pump, a U6K i n j e c t o r , a yBondapak r e v e r s e phase C^g column, and a 440 U V - v i s i b l e d e t e c t o r . The d e t e c t o r was s e t a t 546nm. The samples were e l u t e d w i t h a 70 percent methanol-30 percent 0.01M ammonium a c e t a t e b u f f e r . I t i s obvious t h a t as t h e rose bengal photodegrades, a m u l t i p l i c i t y o f products appears. F u r t h e r , due t o t h e decrease i n r e l a t i v e

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Halogenated Xanthene Dyes

ΗΕΓΓΖ AND WILSON

0

10

5 TIME (DAYS)

Figure 1. Light-independent mortality as a function of time of exposure to rose bengal in the food supply of the boll weevil (x), the imported fire ant

2

FT

T,

_ ^

,h s|(s

1Λ

ROSE BENGAL

OXYGEN

Figure 2. Scheme suggested for the dye-sensitized photooxidation opera­ tive with the substituted xanthene series of dyes. (See text for explana­ tion of symbols. Reproduced from Reference 10).

Figure 3. The mo­ lecular structure of the xanthene dyes studied in this work. (See text for expla­ nation of the substituents A and B. Reproduced from Reference 5.)

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

40

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 4. The visible absorbance trum of a rose bengal solution been photodegradea by sunlight is shown by Trace A. Trace Β is the spectrum of the rose bengal solution before exposure to sunlight.

Figure 5. High-performance liquid chromatographic trace of purified rose bengal (left) and partially photodegraaed rose bengal (right) observed with a 546-nm absorbance

400

500 WAVELENGTH (nm)

TIME

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

600

4.

ΗΕΓΤΖ AND WILSON

41

Halogenated Xanthene Dyes

1

r e t e n t i o n ( k ) o f the p r o d u c t s , one can p o s t u l a t e t h a t these products are more p o l a r than rose bengal. F i n a l l y , t h e f a c t t h a t these products are a b l e t o be d e t e c t e d a t 546nm and t h e f a c t t h a t completely photodegraded rose bengal has no v i s i b l e a b s o r p t i o n , i n d i c a t e s t h a t each o f these products i s an interme­ d i a t e i n the o v e r a l l r e a c t i o n . Although rose bengal and the photodegraded products do n o t absorb i n the u l t r a v i o l e t as s t r o n g l y as i n the v i s i b l e , the UV t r a c e s o f the l i q u i d chromatographic s e p a r a t i o n are shown i n F i g u r e 6. Pure rose bengal i s shown on the l e f t and p a r t i a l l y photodegraded rose bengal on the r i g h t . A g a i n , i t may be seen t h a t a l l o f the products formed d u r i n g t h i s r e a c t i o n are more p o l a r ; t h a t i s , a lower k , than rose bengal i t s e l f . In F i g u r e 7, the tw are presented together 546nm a b s o r p t i o n t r a c e . The p o s i t i o n o f rose bengal on these t r a c e s would correspond w i t h the s t r o n g doublet on the 546nm t r a c e . The p u r i f i c a t i o n and i d e n t i f i c a t i o n o f these i n t e r m e d i a t e compounds i s c u r r e n t l y an area o f prime c o n s i d e r a t i o n i n our laboratory. The r a t e o f photodegradation o f the xanthene dyes has a l s o been s t u d i e d . F i g u r e 8 shows the decrease i n absorbance a t 546nm o f s o l u t i o n s o f rose bengal as a f u n c t i o n o f i l l u m i n a t i o n time a t 5 l i g h t i n t e n s i t i e s between lmE/m «sec and 6mE/m . s e c . The l o g a r i t h m o f the absorbance i s l i n e a r l y dependent on t h e time o f i l l u m i n a t i o n and i s i n d i c a t i v e o f a f i r s t order r a t e o f r e a c t i o n . The pseudo f i r s t order r a t e constant (k^) can be c a l c u l a t e d f o r each r e a c t i o n by the method o f h a l f - l i v e s . I f the k i v a l u e s are p l o t t e d as a f u n c t i o n o f the l i g h t i n t e n s i t y used t o generate those v a l u e s , as shown i n F i g u r e 9, one o b t a i n s a l i n e a r r e l a t i o n s h i p . The slope o f t h a t l i n e i s k # a pseudo second order r a t e c o n s t a n t , which p r o v i d e s the b a s i s f o r compari­ son o f the s u s c e p t i b i l i t y t o photodegradation o f the v a r i o u s dyes (Table I I ) . By t h i s c r i t e r i o n , e r y t h r o s i n Β i s the most r e a d i l y photodegradable w i t h e o s i n y e l l o w i s h and rose bengal c l o s e behind. The two dyes t e s t e d which c o n t a i n no halogen, rhodamine Β and f l u o r e s c e i n , are most r e s i s t a n t t o photodegrada­ t i o n . I t appears t h a t halogen on the upper r i n g system f a c i l i ­ t a t e s the r e a c t i o n w h i l e halogen presence on the lower r i n g r e t a r d s the photodegradation r e a c t i o n . I t may a l s o be mentioned t h a t phosphorescent dyes g e n e r a l l y photodegrade w h i l e f l u o r e s c e n t dyes do not. A t low dye c o n c e n t r a t i o n s , the r e a c t i o n i s c l e a r l y f i r s t order (Figure 10). As the i n i t i a l c o n c e n t r a t i o n i n c r e a s e s , t h e top l i n e f o r i n s t a n c e , t h e i n i t i a l p o r t i o n o f the r e a c t i o n i s slower than the f i r s t order r e a c t i o n observed a t lower concentra­ t i o n s . When the o v e r a l l r e a c t i o n i s observed a t v e r y h i g h c o n c e n t r a t i o n s , a d d i t i o n o f the two r e a c t i o n s y i e l d e d apparent zero order data. 1

2

2

2

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

42

DISPOSAL AND DECONTAMINATION OF PESTODES

<

QC Z UJ

ο ζ ο ο UJ > h< _J

Figure 6. High-performance liquid chromatographic trace of purified rose bengal (left) and partially photode­ graded rose bengal (right) observed with a 280-nm absorbance detector

TIME

< oc

2 k—

5

Figure 7. Direct comparison of partially photodegraded rosebengal according to 280-nm absorbance (top) and 546-nm absorbance (bottom)

TIME

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4.

ΗΕΓΤΖ AND WILSON 0.30

43

Halogenated Xanthene Dyes

f

0.10

0.03

60 120 ILLUMINATION TIME (MIN)

180

Figure 8. Semi-log plot showing the de­ crease in absorbance of a rose bengal solution as a function of illumination time. Each trace represents data taken at a different intensity: (·), 1.0; (O), 2.0; (m), 3.5; (Π), 5.0; (x), 6.0; mE/m 'sec. 2

4

Figure 9. The rate constant k plotted as a function of the inci­ dent light intensity t

I 2 3 4 5 6 LIGHT INTENSITY (mE/m sec) 2

40

120

80

ILLUMINATION TIME

(MIN)

Figure 10. Semi-log plot showing the de­ crease in absorbance of rose bengal solu­ tions as a function of illumination time. Each trace represents data taken at a dif­ ferent rose bengal concentration: (x), 3.3 X 1(T*M; (O), 6.6 X 10'M; (·), 13.2 X JO M.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

e

DISPOSAL AND DECONTAMINATION OF PESTICIDES

44

F i g u r e 11 shows t h i s e f f e c t from a d i f f e r e n t v i e w p o i n t . I f k^, c a l c u l a t e d from the h a l f - l i f e , i s p l o t t e d a g a i n s t t h e i n i t i a l rose bengal c o n c e n t r a t i o n , t h e r e a c t i o n r a t e i s found t o decrease as t h e rose bengal c o n c e n t r a t i o n i n c r e a s e s t o about 6 χ 1 0 " % , a t which p o i n t t h e r a t e becomes independent o f dye c o n c e n t r a t i o n . Below 4 χ 10" M, as shown i n t h e i n s e t , t h e r a t e i s a l s o indepen­ dent o f rose bengal c o n c e n t r a t i o n . I t may be hypothesized t h a t e i t h e r s u b s t r a t e quenching o f the e x c i t e d s t a t e by the dye may cause t h e decrease i n r e a c t i o n r a t e o r e l s e l i g h t i s r a t e l i m i t i n g a t c o n c e n t r a t i o n s higher than 6 χ 10" M. 6

5

Table I I Relativ Erythrosin Β Eosin Yellowish Rose Bengal Phloxin Β Fluorescein Rhodamine Β

12 10 10 5 1 0

Another q u e s t i o n o f c r i t i c a l importance t o t h i s study i s whether t h e dyes a r e d e t o x i f i e d d u r i n g t h e photodegradation process. Table I I I shows t h a t completely photodegraded rose bengal was completely i n e f f e c t i v e i n e l i c i t i n g the l i g h t - c a t a l y z e d t o x i c r e a c t i o n which was induced by t h e presence o f undegraded rose bengal. Both rose bengal s o l u t i o n s were made up a t 7 χ 10" M; one was photodegraded i n s u n l i g h t and t h e other l e f t i n t h e dark. Both s o l u t i o n s were concentrated t o an e f f e c t i v e l e v e l o f 5 χ 10" M b e f o r e f e e d i n g t o t h e house f l i e s f o r 24 h r s i n t h e dark. A f t e r 21 h r s exposure t o the f l u o r e s c e n t l i g h t , 95 percent m o r t a l i t y was observed due t o undegraded rose bengal compared w i t h zero m o r t a l i t y i n both photodegraded r o s e bengal and c o n t r o l p o p u l a t i o n s . A second experiment where t h e rose bengal c o n c e n t r a t i o n s were 2.5 χ 10" M, showed s i m i l a r r e s u l t s . F l i e s t r e a t e d w i t h undegraded rose bengal were a l l dead w i t h i n 5 hrs o f l i g h t exposure. There were no dead f l i e s i n e i t h e r t h e degraded rose bengal o r c o n t r o l p o p u l a t i o n s . These r e s u l t s were not a l l t h a t s u r p r i s i n g s i n c e the photodegraded rose bengal does not absorb v i s i b l e l i g h t . Table IV, however, shows a key e x p e r i ­ ment. The photodegraded dye was a l s o i n c a p a b l e o f e l i c i t i n g t h e l i g h t - i n d e p e n d e n t t o x i c r e a c t i o n caused by undegraded rose bengal. Upon f e e d i n g on 2.5 χ 1 0 " % undegraded rose bengal i n the dark, m o r t a l i t y was observed a f t e r 72 h r s and by 96 h r s , 90 percent o f the f l i e s were dead. There was no t o x i c i t y i n t h e other two p o p u l a t i o n s . 6

4

3

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4.

ΗΕΓΓΖ AND WDLSON

Halogenated Xanthene Dyes

45

Table I I I T o x i c i t y t o House F l i e s o f Photodegraded and Undegraded Rose Bengal i n t h e L i g h t

Treatment

0

Control Rose Bengal* Photodegraded Undegraded

0

a

Time o f I l l u m i n a t i o n (hr) 19 17 15 12 3

21

0

0

0

0

0

0

0

0

0

0

0

0

5

a

b

0

D a t a presented as percent m o r t a l i t y where the c o n t r o l was one chamber o f 10 f l i e s and t h e dye-treated were two chambers o f 10 f l i e s each. I n i t i a l rose bengal s o l u t i o n s were 7 χ 10""% i n d i s t i l l e d water. Photodegraded samples were exposed t o s u n l i g h t f o r 3 days, undegraded samples were kept i n t h e dark f o r same time p e r i o d . Dye samples were concentrated t o 5 χ 1 0 ~ % f o r adminis­ tration to f l i e s .

Table IV T o x i c i t y t o House F l i e s o f Photodegraded and Undegraded Rose Bengal i n t h e Dark

Treatment Control Rose Bengal* Photodegraded Undegraded

Time o f I l l u m i n a t i o n (hr) 84 72 36 60

0 0

a

96

0

0

0

0

0

0 0

0 0

0 0

0 30

0 90

3

0 0

a

D a t a presented as p e r c e n t m o r t a l i t y where each treatment was one chamber o f 10 f l i e s each. ^ I n i t i a l rose bengal s o l u t i o n s were 7 χ 1 0 " % i n d i s t i l l e d water. Photodegraded samples were exposed t o s u n l i g h t f o r 3 days, undegraded samples were kept i n t h e dark f o r same time p e r i o d . Dye samples were concentrated t o 2.5 χ 1 0 " % f o r a d m i n i s t r a t i o n to f l i e s .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

46

:

r

-,

Q

10

•

„>»»

Qβ

Λ

<)

l2

• ·

2 4 6 8 ROSE BENGAL (I0M) 6

\

•

:

\V »

Figure 11. The apparent firstorder rate constant k plotted as a function of rose concentration t

Figure 12. The toxic effect of rose bengal on Stapholococcus aureus (right) as compared with photode­ graded rose bengal (left)

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4. ΗΕΓΓΖ AND WILSON

Halogenated Xanthene Dyes

Figure 13. The toxic effect of rose bengal on Bacil­ lus cereus (right) as compared with photodegraded rose bengal (left)

American Chemical Society Library 1155 16th St., N.W.

In Disposal and Decontamination of Pesticides; Kennedy, M.; D.C.Society: 20036 ACS Symposium Series;Washington, American Chemical Washington, DC, 1978.

47

DISPOSAL AND DECONTAMINATION OF PESTICIDES

48

The same q u e s t i o n o f photodegradation and d e t o x i f i c a t i o n has been s t u d i e d w i t h r e s p e c t t o b a c t e r i a . F i g u r e 12 shows an agar p l a t e t o which Stapholococcus aureus had been added d u r i n g p r e p a r a t i o n . A s m a l l d i s c o f f i l t e r paper i s p l a c e d on t h e agar p l a t e and the s o l u t i o n t o be t e s t e d i s added t o t h e f i l t e r paper. In t h i s case, 7.75 χ 1 0 " undegraded r o s e bengal and t h e same c o n c e n t r a t i o n o f photodegraded rose bengal a r e t e s t e d . While the b a c t e r i a grows, t h e s o l u t i o n w i l l d i f f u s e from the f i l t e r paper o u t i n t o t h e agar. I f t h e s o l u t i o n i s t o x i c t o the b a c t e r i a , a c l e a r h a l o o f nongrowth w i l l surround t h e d i s c . T h i s i s t h e case w i t h undegraded rose bengal on t h e l e f t . I f the s o l u t i o n i s n o n t o x i c t o t h e b a c t e r i a , the growth w i l l occur r i g h t up t o t h e d i s c . T h i s i s t h e case w i t h the photo­ degraded rose bengal on t h e r i g h t . I t may a l s o be observed t h a t the growth o f t h e b a c t e r i a , B a c i l l u s cereus, i s a f f e c t e d by undegraded rose bengal rose bengal on t h e r i g h The r e s u l t s o f these ongoing i n v e s t i g a t i o n s have shown t h a t s u b s t i t u t e d xanthene dyes may be photodegraded q u i t e e f f e c t i v e l y by o r d i n a r y v i s i b l e l i g h t s i m i l a r t o t h e l e v e l s found i n t h e environment. Furthermore, t h e photodegradation r e a c t i o n leads to a complex mixture o f i n t e r m e d i a t e s and products. I t has a l s o been shown t h a t t h e photodegradation products a r e n o n t o x i c t o both i n s e c t s and b a c t e r i a i n both the light-dependent and the l i g h t - i n d e p e n d e n t mechanisms. MAFES P u b l i c a t i o n No. 8532. 4

Literature Cited 1.

Yoho, T. P., Butler, L . , and Weaver, J. E. J. Econ. Entomol. (1971). 64:972-3. 2. Yoho, T. P., Weaver, J. Ε., and Butler, L. Environ. Entomol. (1973). 2:1092-6. 3. Broome, J. R., Callaham, M. F., Lewis, L. Α., Ladner, C. Μ., and Heitz, J. R. Comp. Biochem. Physiol. (1975). 51C: 117-21. 4. Callaham, M. F., Lewis, L. Α., Holloman, Μ. Ε., Broome, J. R., and Heitz, J. R. Comp. Biochem. Physiol. (1975). 51C: 123-8. 5. Callaham, M. F., Broome, J. R., Lindig, Ο. Η., and Heitz, J. R. Environ. Entomol. (1975). 4:837-41. 6. Broome, J. R., Callaham, M. F., and Heitz, J. R. Environ. Entomol. (1975). 4:883-6. 7. Yoho, T. P., Butler, L., and Weaver, J. E. Environ. Entomol. (1976). 5:203-4. 8. Broome, J. R., Callaham, M. F., Poe, W. Ε., and Heitz, J. R. Chem.-Biol. Interact. (1976). 14:203-6. 9. Callaham, M. F., Broome, J. R., Poe, W. Ε., and Heitz, J. R. Environ. Entomol. (1977). 6:669-73. 10. Callaham, M. F., Palmertree, C. Ο., Broome, J. R., and Heitz, J. R. Pest. Biochem. Physiol. (1977). 7:21-7. 11. Lindig, O. H. and Malone, O. C. J. Econ. Entomol. (1973). 66:566-7. MARCH 23,

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

5 Detoxification of Pesticides and Hazardous Wastes by the Microwave Plasma Process LIONEL J. BAILIN and BARRY L. HERTZLER Department of Chemistry, Lockheed Palo Alto Research Laboratory, 3251 Hanover Street, Palo Alto, CA 94304 DONALD A. OBERACKER Solid and Hazardous Waste Research Division, Municipal Environmental Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268

Of the approximately 10 million tons of toxic and hazardous wastes which are generated yearly in the United States, it has been estimated that 10 to 20% will need special methods for dis­ posal because of extrem materials are made up i been withdrawn from use, obsolete or below-specification toxic substances, industrial wastes from chemicals, explosives, etc., and biological residues, carcinogens, mutagens, and related mate­ rials (1). They exist in multiple ton quantities, as well as small centigram batches at a multitude of locations throughout the United States. They are, specifically, materials in search of a disposal method, and include the following exceedingly dangerous compounds and mixtures: ο Cancer-causing nitrosamines, vinyl and vinylidene chlorides, dioxin-containing organohalogens, and aromatic amine com­ pounds which heretofore have been considered only as oddities, or as being present only in small quantities ο Acute-toxicity organometallic compounds and heavy metal com­ plexes, such as mercury, arsenic, cadmium, and lead compounds, derived from industrial processes and pesticides ο Nerve-poisons from military sources, which include organophosphorus chemicals stockpiled above ground, and from pesti­ cide wastes which are only slightly less hazardous All of these are problem materials which give great concern to those who are responsible for their safe disposal. Their identi­ fication and sources (2) are abstracted in Table I. Current Disposal Techniques for Highly Toxic Materials For compounds of nominal toxicity, such as diluted DDT or other pesticides mixed with solvent or municipal sludges, on the order of LD50* of 500 or higher, notable achievements have been accomplished in thermal destruction, chemical and biological de­ toxification, and special landfill methods. However, with the ex­ ception of incinerator processing, relatively l i t t l e new technol*0ral lethal dose for 50% of test animals in mg/kg of body weight. 0-8412-0433-0/78/47-073-049$06.00/0 This chapter not subject to U.S. copyright. Published 1978 American C h e m i c a l Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Nerve gases or G-agents

Pesticides (phosphonates, tMophosphonates)

Mercurials pestlcidee

Lead (tetraethyl lead)

Metal cyanides

Nickel carbonyl, Zn, Cd, Mn, Se, V,

•

•

•

•

Aromatic amines (e.g., benzidines)

Potyaromatlc hydrocarbons, PAH (dyes.

•

•

Carcinogens, teratogens, mutagens

Carcinogens

Male sterility In humane

Carcinogen*

Primary organ toxlna

Primary organ toxins In humane

Lipoid toxin

Anticholinesterase

Carcinogen

Anticholinesterase nerve toxin

(a) LDgo < 100 (oral lethal dose 80% test animals, < 100 mg/1 kg body weight). (b) Temporary method: Materials nave not been rendered chemically or btologlcaUy safe.

Nttrosemlnea (e.g., dimethyl nJtrosamlne)

•

Or*anonitro*en Compounds:

Vinyl and vlnylldene chlorides

e

PC Be, Kepooe, Mlrex, etc.

H exachlo robenzene (containing dioxin)

DBCP (dlbromocUoropropane)

•

•

Halofjenated Compounds-

Misc. Heavy metal compounds

Arsenical pesticides

•

OmnometaUlc Compounda:

FlaxiM retardent («.g., T r U " )

•

(phoaphooflfluoridate a)

•

•

Orgmnct^spoorus Compound.:

Classification

U.S. Navy smokes, flares, etc.

Centers.

Industrial, Hospitals, Universities, Cancer

Industrial waste streams and process bottoms

Fumleant/agricultural chemicals

Commercial, Agricultural

experimental complexes

Petroleum catalysts, pestlcidee,

Plating wastes, solids

Process wastes

Solids, solutions

100's of lb

100's of lb

l to 10 lb (throughout U.S.)

Estimated 1000's of lb

Estimated 1000's of l> (California)

1000's of lb

(Texas, California, New Jersey)

I to 100 lb, a few 1000'e of lb

ΙΟΟΟ'β of lb (East and West Coast)

100's of lb, gallons

100 to 1000 gallons

New Mexico)

100's of lb

SoUds

1 to 10,000 lb in various locations

Probable 1000·β of lb (California)

(Colorado, Utah, Maryland)

Several thousand lb

Thousands of gallons

Quantities and Location, Where Known

Holding ponds (Alexandria, Va. area)

Commercial, Industrial, Agricultural:

Unlabeled, unknown supplies

Outdated supplies

Pesticide manufacturing wastes

Commercial, Industrial, Agricultural:

Manufacturer

streams. Stored neutralization products

Military: Stored pure agents. Stored «mate

Source of Material

Unknown

Storage above and below ground

Storage and Incineration

Unknown

Storage above sad underground. Incineration

Storage above and underground

Wet oxidation, UV, oxonolyels

Storage above and underground

Storage above grote%d

Storage underground

Storage above ground

Incineration

Chemical disposal sites.

Storage^ above ground

Disposal Method

Identities and Known Sources of Highly Toxic and Hazardous Substances within Continental U.S.

Toxic Material

Table I.

8

5.

BAILIN ET

AL.

Detoxification of Pesticides and Wastes

51

ogy has been developed w i t h i n the l a s t 10 years f o r the d i s p o s a l of h i g h l y t o x i c , r e f r a c t o r y , and extremely p e r s i s t e n t wastes i n the form of concentrates, pure chemicals, o r n o n d i l u t e d process wastes. Current methods have been almost e x c l u s i v e l y underground l a n d f i l l , or aboveground warehouse or exposed-drum storage. This i s not a true d i s p o s a l , but a " h i d i n g " a c t i o n , i n that the mater i a l s are s t i l l t h e r e , i n p l a c e , w a i t i n g f o r a method which w i l l c a r r y out the d e t o x i f i c a t i o n e v e n t u a l l y . The substances w i l l a c t u a l l y remain f o r f u t u r e generations to be t r o u b l e d w i t h . P r e l i m i n a r y Microwave Plasma D e t o x i f i c a t i o n Studies Research on the decomposition of organic compounds by passage through a microwave discharg search Laboratory (LPARL microwave discharges could be used to promote a v a r i e t y of chemic a l r e a c t i o n s (3), i t was considered reasonable t h a t t h i s approach could be a p p l i e d t o the s c i s s i o n or d e s t r u c t i o n of bonds i n compounds which, f o r v a r i o u s reasons, were considered o b j e c t i o n a b l e . In a U. S. Army-supported program conducted during 1970-1972, the decomposition of t o x i c gas simulants was c a r r i e d out i n discharges c o n t a i n i n g h e l i u m and a i r i n which n e a r l y 100% decomposition of s e l e c t e d organophosphonate m a t e r i a l s was e f f e c t e d (4)· The mater i a l s were passed through a s m a l l 1-5 g/hr c a p a c i t y l a b o r a t o r y s i z e r e a c t o r , having a plasma volume of about 10 cm^. For commerc i a l o r p l a n t - s c a l e development of the process, i t was obvious that l a r g e - c a p a c i t y r e a c t o r s would be r e q u i r e d . When i t was d e t e r mined that l a r g e r s i z e microwave power a p p l i c a t o r s could be obt a i n e d on a custom b a s i s from microwave hardware s u p p l i e r s , the U. S. EPA, S o l i d and Hazardous Waste Research D i v i s i o n , M u n i c i p a l E n v i ronment a l Research Laboratory, C i n c i n n a t i , Ohio, supported the f o l l o w i n g study t o t e s t the process on s e v e r a l t o x i c p e s t i c i d e s and wastes. Program O b j e c t i v e s The primary o b j e c t i v e o f the program was e v a l u a t i o n of the e f f e c t i v e n e s s of an expanded s c a l e microwave plasma system f o r processing hazardous organic compounds, wastes, and p e s t i c i d e s of current i n t e r e s t . The r e a c t i o n products would a l s o be i d e n t i f i e d to v e r i f y that the products were innocuous, and to assess the p o s s i b i l i t y f o r recovery o f u s e f u l m a t e r i a l s as by-products. The data presented below describes the chemistry of the r e a c t i o n s , the i n i t i a l scale-up of microwave hardware, and an e v a l u a t i o n of the process i n which 450 to 3200 grams (1 t o 7 l b ) per h r were decomposed to harmless or r e a d i l y disposable e f f l u e n t s . Microwave Plasma C h a r a c t e r i s t i c s A plasma or discharge i s a p a r t i a l l y i o n i z e d gaseous mixture c o n s i s t i n g o f f r e e e l e c t r o n s , i o n s , and v a r i o u s n e u t r a l s p e c i e s . The f r e e e l e c t r o n s are the p r i n c i p a l i n i t i a t o r s of the plasma

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

52

DISPOSAL AND DECONTAMINATION OF PESTICIDES

r e a c t i o n s . When the e l e c t r o n s undergo i n e l a s t i c c o l l i s i o n s w i t h the r e a c t a n t s , they cause e i t h e r i o n i z a t i o n , which produces more e l e c t r o n s and i o n s , o r d i s s o c i a t i o n o f the reactants i n t o f r e e r a d i c a l s . These fragments, w i t h t h e i r unpaired e l e c t r o n s , can then undergo a s e r i e s o f r a p i d r e a c t i o n s t o the f i n a l products. The f r e e e l e c t r o n s are energized by t h e o s c i l l a t i n g e l e c t r i c f i e l d produced by the microwave energy (2450 MHz) a p p l i e d to the gas. I n t h i s way, the e l e c t r o n s couple the e l e c t r i c a l energy w i t h t h e reactants and f o r c e them to undergo the d e s i r e d r e a c t i o n s . The o s c i l l a t i n g e l e c t r i c f i e l d produced by the microwaves changes p o l a r i t y so r a p i d l y that the charged species i n t h e plasma reverse t h e i r d i r e c t i o n o f a c c e l e r a t i o n before they are swept to the w a l l s where they are l i k e l y t o be destroyed. Therefore, the plasma can be maintained without th f i n t e r n a l e l e c t r o d e which u s u a l l y r e q u i r e d f o r plasma sequently, there i s no proble decomposi t i o n from c o r r o s i v e species i n the plasma. The plasma used i n these i n v e s t i g a t i o n s i s operated a t r e duced pressures up t o a few hundred t o r r . This permits the f r e e e l e c t r o n s t o be energized to temperatures much higher than that o f the n e u t r a l gases, s i n c e a t these lower pressures there are many l e s s i n e l a s t i c c o l l i s i o n s o c c u r r i n g which would c o o l down the r e a c t i v e e l e c t r o n s . The e l e c t r o n "temperatures" a r e w e l l over 10,000°K (_3) , w h i l e the temperature o f the n e u t r a l gas i s l e s s than 1,000°K. By o p e r a t i n g under these n o n e q u i l i b r i u m c o n d i t i o n s , i t i s p o s s i b l e t o maintain t h e f r e e e l e c t r o n s a t h i g h temperatures without h e a t i n g the bulk n e u t r a l gas, thereby conserving e l e c t r i c a l energy. Since the plasma decomposition mechanism i s p r i n c i p a l l y e l e c t r o n i c , r a t h e r than thermal, the microwave a p p l i c a t o r power c o u p l i n g equipment can be maintained a t r e l a t i v e l y low temperatures . Thus, t h e m a t e r i a l s o f c o n s t r u c t i o n a s s o c i a t e d w i t h furnaces o r i n c i n e r a t o r equipment are g e n e r a l l y unnecessary, and maintenance expenses w i l l be low. I n a d d i t i o n , the systems are leak t i g h t , which i s a r e s u l t o f the requirement f o r working a t reduced pressures, thereby c o n t r i b u t i n g to a h i g h l e v e l o f s a f e t y i n o p e r a t i o n . Reference Ji may be consulted f o r a d d i t i o n a l i n f o r mation on these c h a r a c t e r i s t i c s . EQUIPMENT AND MATERIALS Microwave Plasma Systems Microwave plasmas were produced i n a l a b o r a t o r y - s i z e resonant c a v i t y , and by three dual-trough waveguide a p p l i c a t o r s . A block diagram o f the plasma system i s shown i n Figure 1, and app l i e s t o a l l systerns i r r e s p e c t i v e o f a p p l i c a t o r type o r power source. The l a b o r a t o r y s c a l e plasma was used during the i n i t i a l stages o f the study to determine product i d e n t i t i e s and convers i o n e f f i c i e n c i e s . The l a b o r a t o r y apparatus was e s s e n t i a l l y the same as t h a t u t i l i z e d p r e v i o u s l y f o r the decomposition o f organo-

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

BAJON ET AL.

Detoxification

of Pesticides

and Wastes

MATERIAL TO BE DETOXIFIED AND REACTANT GAS (OXYGEN)

MICROWAVE PLASMA REACTOR

TUNING CIRCUITRY

MICROWAVE POWER SOURCE

2450 MHz

GASES

PRODUCT RECEPTOR TRAPS

LIQUIDS, SOLIDS

ANALYTICAL INSTRUMENTATION FOR CHEMICAL ANALYSIS

VACUUM PUMP

Figure

I. Block diagram of microwave related components

plasma system and

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

54

DISPOSAL AND

DECONTAMINATION OF PESTICIDES

phosphonate compounds, but r e q u i r e d a m o d i f i c a t i o n i n technique f o r the dropwise i n t r o d u c t i o n of l i q u i d s . A g r a v i t y - f e e d pressuree q u a l i z e d dropping funnel o f approximately 100 cm c a p a c i t y was i n s t a l l e d at the input t o the plasma r e a c t o r f o r t h i s purpose. A method was a l s o r e q u i r e d to increase the time f o r passage o f the drops through the discharge. This was n e c e s s i t a t e d s i n c e the time of f a l l under vacuum through the plasma was too s h o r t , as evidenced by drops e x i t i n g the r e a c t o r without having reacted comp l e t e l y . A s o l u t i o n to the problem was obtained by u t i l i z i n g a hollow quartz mesh "basket" p o s i t i o n e d at the center of the plasma zone. Quartz mesh f i b e r s were loaded i n t o the basket to serve as a contact area f o r the drops. The basket contained a number of holes to a l l o w passage of the e f f l u e n t products. The residence time of the drops w i t h i 1/ sec, the time f o r r e a c t i o zone. A schematic of the expanded s c a l e plasma system i s shown i n Figure 2. The microwave power a p p l i c a t o r and power supply hardware were s u p p l i e d by G e r l i n g Moore, Inc., Palo A l t o , CA. The p r i n c i p a l d i f f e r e n c e between the l a t t e r system and the l a b o r a t o r y model i n v o l v e s the method o f a p p l i c a t i o n of power to the r e a c t o r . In the l a b o r a t o r y u n i t , the a p p l i c a t o r was a resonant c a v i t y , V a r i a n A s s o c i a t e s , Model EC2DRS2, which was fed by a s i n g l e 2.5kW 2450-MHz power supply. I n the expanded s c a l e u n i t , a d u a l trough waveguide a p p l i c a t o r was used i n which each trough was fed by a 2.5-kW 2450-MHz power source. For a d d i t i o n a l i n f o r m a t i o n on the a p p l i c a t o r s , Reference j5 may be c o n s u l t e d . In the expanded s c a l e systems, the r e a c t o r tubes were f a b r i cated from transparent quartz of about 50 mm o.d., and 1.5-2.0 mm w a l l t h i c k n e s s . Quartz Raschig r i n g s and, i n some i n s t a n c e s , quartz wool plugs were used to f i l l s e c t i o n s of the r e a c t o r to increase the residence time w i t h i n the plasma zone. The l i q u i d feed system was based on a 1 - l i t e r p r e s s u r e - e q u a l i z e d v e r s i o n of the u n i t used f o r the l a b o r a t o r y s c a l e plasma t e s t s . For r e l a t i v e l y v o l a t i l e s o l u t i o n s , however, atmospheric pressure was maint a i n e d above the s o l u t i o n t o avoid vacuum pumping the s o l v e n t from the s o l u t i o n . In t h i s i n s t a n c e , a 250 cm v o l u m e t r i c dropping buret was used f o r feeding d i r e c t l y i n t o the r e a c t o r . Reduced pressures were obtained u s i n g a Welch DuoSeal Model 1397 o i l - s e a l e d 2-stage mechanical pump w i t h a f r e e a i r d i s p l a c e ment of 425 l i t e r s per min. Various c o l d t r a p c o n f i g u r a t i o n s were i n s t a l l e d between the r e a c t o r output and the pump f o r product c o l l e c t i o n , and to maintain c l e a n l i n e s s of the pump o i l . A photograph of t y p i c a l system components i s shown i n Figure 3. During the o p e r a t i o n of the microwave u n i t s , a Holaday Model HI 1500-3 microwave r a d i a t i o n monitor (Holaday I n d u s t r i e s , Inc., Edina, Minnesota), and a Narda Model B86B3 r a d i a t i o n monitor (Narda Microwave Corp., P l a i n v i e w , N.Y.) were used to monitor power leakage. Levels were l e s s than 1 mW/cm i n the immediate v i c i n i t y of the discharge tube. 3

3

2

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

5.

Detoxification

BAILIN ET AL.

of Pesticides

55

and Wastes

DROP-FEED BURET

QH MICROWAVE POWER SOURCE * s

MICROWAVE / APPLICATOR —

Ch MICROWAVE \ POWER SOURCE ^

RECEIVER Figure 2.

PLASMA REACTORI ION [TUBE -y PUMP /

/

FLOWMETER

[]

/

GAS SUPPLY

MASS SPECTROMETER •

3-WAY STOPCOCK

^-VARIABLE-LEAK I VALVE

'THROTTLE VALVE

MANOMETER SMALL VACUUM PUMP COLD TRAP

iff

THROTTLE VALVE

COLD TRAP

Schematic of expanded-scale microwave plasma system

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

MAIN VACUUM PUMP

56

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 3.

Microwave plasma detoxification system

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

5.

BAILIN ET AL.

Detoxification of Pesticides and Wastes

57

A n a l y t i c a l Systems Mass s p e c t r o m e t r i c (MS) a n a l y s i s of the gases l e a v i n g the r e a c t o r was performed on a V a r i a n A s s o c i a t e s Model 974-0002 r e s i d u a l gas a n a l y z e r (quadrupole mass spectrometer) w i t h a range of 250 atomic mass u n i t s . A s m a l l q u a n t i t y of the gas was c o n t i n uously pumped past a v a r i a b l e - l e a k sampling v a l v e . The gases b l e d i n t o the mass spectrometer by the sampling v a l v e were pumped from the system by an i o n pump. The sampling system i s i n c l u d e d i n Figure 3. I n f r a r e d s p e c t r a of s o l i d and l i q u i d e f f l u e n t s c o l l e c t e d from the product r e c e i v e r and traps were obtained on a P e r k i n Elmer 621 i n f r a r e d spectrophotometer w i t h a range o f 4000 to 400 cm"" (2.5 to 25 microns). M a t e r i a l s to be analyzed were ground w i t h KBr and compressed i n t o p e l l e t s f o r scanning over the p r e s c r i b e d spectrum. V i s i b l e and u l t r a v i o l e and l i q u i d e f f l u e n t s were obtained on a Cary Model 14 Recording Spectrophotometer u s i n g c o n v e n t i o n a l procedures. A Finnegan Model 4021 GC/MS Data System was used toward comp l e t i o n o f the study f o r polyaromatic hydrocarbons. 1

P e s t i c i d e s , Hazardous Wastes » and Gases The m a t e r i a l s which were d e t o x i f i e d or decomposed are l i s t e d i n Table I I . S e l e c t i o n s were made on the b a s i s of the extent of the environmental problems which were a s s o c i a t e d w i t h these mater i a l s , EPA s i n t e r e s t , and the r e f r a c t o r y c h a r a c t e r i s t i c s of the m a t e r i a l s . The r e a c t a n t / c a r r i e r gases were the f o l l o w i n g : oxygen, 99.5% min. p u r i t y , Fed. Spec. BB-0-925(a), Type I ; argon, 99.995% min. p u r i t y , Mil-A-18455B. The oxygen contained 0.5% maximum i m p u r i t i e s , i n which approximately 0.05% was n i t r o g e n , the remainder being argon and other gases i n t r a c e amounts. 1

EXPERIMENTAL PROCEDURE In g e n e r a l , the procedure f o r o p e r a t i o n of both l a b o r a t o r y and expanded s c a l e u n i t s was the same as that d e s c r i b e d i n Reference C e r t a i n m o d i f i c a t i o n s were r e q u i r e d as the r e s u l t of d i f ferences i n feed technique, however. For example, when a vacuum dropping funnel was used f o r i n t r o d u c t i o n of a low v o l a t i l i t y f l u i d , the e n t i r e system, i n c l u d i n g the s e c t i o n above the l i q u i d , was evacuated to 1 t o r r . The pressure was then adjusted to about 10 t o r r by the a d d i t i o n o f oxygen o r argon. The microwave power was then turned on to s t a r t the plasma. A d d i t i o n a l gas was i n t r o duced to o b t a i n the d e s i r e d pressure and f l o w r a t e i n combination w i t h r e g u l a t i o n by the main t h r o t t l e v a l v e . The microwave power was set to the d e s i r e d l e v e l w i t h the t u n i n g c o n t r o l s adjusted to give minimum r e f l e c t e d power. A f t e r o b t a i n i n g a background MS scan (reactant gas f l o w i n g minus m a t e r i a l to be d e t o x i f i e d ) , a needle v a l v e at the bottom of the dropping funnel was opened to y i e l d the d e s i r e d feed r a t e . The gaseous e f f l u e n t from the plasma was then sampled and analyzed by MS. For methyl bromide gas, the

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978. ULV Aroclor 1242 Aroclor 1254

Troysan PMA-30

80% Powder Concentrate, Technical Grade, Code 9406 U.S. Navy MK 13 Mod Ο Marine Smoke and Illumination Signal

Monsanto

Matheson Gas

Troy Chemical Allied Chemical

Naval Weapons Support Center Crane, Indiana

Liquid Mixture

Commercial Gas

Commercial Aqueous Methanol Solution 1. Commercial Powder 2. Laboratory Aqueous Dispersion 3. Laboratory Methanol Solution 1. Laboratory Aqueous Dispersion 2. Laboratory Methyl Ethyl Ketone Solution

PCB's (Polychlorinated Biphenyls)

Methyl Bromide (99.5% min. purity)

Phenylmercuric Acetate (30% PMA solids)

Kepone (80% Active Ingredient, 20% Clay)

55.4% Xylene azo-/3~naphthol 18.9% l-Methylaminanthraquinone 18.0% Sucrose 1.8% Graphite 5.9% Silica Binder (KClOg oxidant excluded)

Chlorinated Hydrocarbon Waste

Brominated Hydrocarbon Rodenticide

Heavy Metal Fungicide

Chlorinated Hydrocarbon Pesticide

Polyaromatic Red Dye Mixture

Grade or Type

American Cyanamid

Manufacturer or Source

Pure Liquid

Form Tested

Malathion (95% min. purity)

Material

Pesticides and Hazardous Wastes for Detoxification Tests

Organophosphorous Pesticide

Classification

Table II.

5.

59

Detoxification of Pesticides and Wastes

BAILIN ET AL.

p e s t i c i d e was f e d d i r e c t l y , bypassing the f u n n e l . Product t r a p s were an i c e water cooled r e c e i v e r , f o l l o w e d by one o r more l i q u i d n i t r o g e n (LN) o r d r y - i c e acetone t r a p s . RESULTS Laboratory Scale Plasma Reactor Reactions i n the l a b o r a t o r y system were c a r r i e d out w i t h the t o x i c substances mixed w i t h oxygen o r argon. Although i t was w e l l known t h a t s i m p l e r o r g a n i c compounds exposed t o i n e r t gas plasmas would r e a c t t o form a v a r i e t y o f compounds, i n c l u d i n g p o l y mers ( 6 ) , n e v e r t h e l e s s , argon, i n a d d i t i o n t o oxygen, was evaluated f o r comparison w i t h the h e l i u m and a i r decomposition r e actions previously reported example, the o f f e n s i v e from the malathion-argon plasma r e a c t i o n s , the formation o f c a r bonaceous f l a k e depositee from methyl bromide-argon, plus a s s e s s i n g the p r o b a b i l i t y f o r the formation o f extremely t o x i c methyl mercury compounds from PMA and other organomercurials i n argon (or other i n e r t gases),emphasis was d i r e c t e d toward u t i l i z a t i o n of oxygen as t h e s o l e r e a c t a n t gas f o r use i n the expanded s c a l e system. D e t a i l s o f the l a b o r a t o r y r e a c t i o n s which l e d t o these conclusions are l i s t e d below. Melathion-oxygen. Cythion ULV grade malathion was passed through a 200 t o 250-W plasma at 100 t o 120 t o r r u s i n g the quartz basket technique. The r e a c t i o n s appeared t o occur spontaneously as the drops contacted the quartz f i b e r s . With the e x c e p t i o n o f a white e t c h zone and a h i g h v i s c o s i t y water-white l i q u i d t h a t formed below the plasma zone, a l l the products were gases. Mass spectrometry i n d i c a t e d CO 2* CO, S 0 , and H 0 as e f f l u e n t gases. I n f r a r e d spectroscopy showed t h e l i q u i d product t o be phosphoric a c i d . M a t e r i a l balances i n d i c a t e d t h a t metaphosphoric a c i d was the probable m a t e r i a l from which conversion t o orthophosphoric a c i d i n moist a i r occurred i n 1 to 2 days. A n a l y s i s f o r malathion i n the l i q u i d r e a c t i o n product was c a r r i e d out s p e c t r o p h o t o m e t r i e s l y i n the v i s i b l e r e g i o n ( 7 ) . Percent conversion was 99.98 + percent based on 0.016 percent malathion determined. P o l y c h l o r i n a t e d b i p h e n y l (PCB) - oxygen. Monsanto A r o c l o r 1242 l i q u i d was passed through a 250-W plasma at 100 t o r r . Mass balance showed no l i q u i d s a t t r i b u t a b l e to the s t a r t i n g m a t e r i a l . A l l the products o f decomposition were gases. On the b a s i s o f c o n t r o l runs i n the absence o f the plasma r e a c t i o n , percent conv e r s i o n was c a l c u l a t e d a t g r e a t e r than 99.9 percent. Gas products were i d e n t i f i e d as C 0 , CO, H 0 , H C l , C l , w i t h minor amounts of C1 0 and C0C1 . The l a t t e r gases, c h l o r i n e oxide and phosgene, were not observed i n the expanded s c a l e plasma r e a c t i o n s ; i n s t e a d , hydrogen c h l o r i d e was the p r i n c i p a l C l - c o n t a i n i n g product. Methyl bromide - oxygen. Gaseous methyl bromide was passed through a 300 t o 400-W 5 0 - t o r r oxygen plasma a t 2 t o 3 g/hr. The products o f r e a c t i o n were C 0 , CO, H 0, HBr, and B r . Oxides o f 2

2

2

2

2

2

2

2

2

2

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND

60

DECONTAMINATION OF PESTICIDES

bromine were found i n the l i q u i d n i t r o g e n t r a p s , but were not otherwise observed at ambient temperatures. The extent o f the r e ­ a c t i o n was determined by mass spectrometer, i n which the r a t i o s o f the CH Br i o n s i g n a l i n t e n s i t i e s before and d u r i n g the plasma r e a c ­ t i o n s were compared. Decomposition was g r e a t e r than 99 p e r c e n t , which was the l i m i t of p r e c i s i o n of the mass spectrometer f o r t h i s chemical system. Phenylmercuric a c e t a t e - oxygen. Commercial Troysan PMA-30 s o l u t i o n was passed through 225 to 280-W plasmas at 120 t o r r . Mer­ cury metal was observed as a m e t a l l i c m i r r o r on the g l a s s t u b i n g downstream from the discharge zone. M a t e r i a l balance i n d i c a t e d >99.9% decomposition to the metal. Mass spectrometry showed the products formed i n a d d i t i o n t o Hg were H2O, CO2, and CO. There was no evidence of dimethy curials. M a l a t h i o n - argon. Decomposition r e a c t i o n s were c a r r i e d out at 200-250 W, 100 t o r r , i n pure argon. The r e s u l t a n t y e l l o w brown products were extremely o f f e n s i v e and malodorous, s i m i l a r to mercaptan and d i s u l f i d e compounds. Because o f t h e i r p o t e n t i a l f o r very h i g h t o x i c i t y , f u r t h e r a n a l y s i s was not undertaken. Methyl bromide - argon. Methyl bromide was mixed w i t h argon and passed through 300 to 400-W plasmas at 50 t o r r . The products of r e a c t i o n estimated by mass spectrometer were B r , HBr, methane, e t h y l e n e , and a c e t y l e n e . Carbonaceous f l a k e d e p o s i t s were formed i n the r e a c t o r tube. Q u a n t i t a t i v e a n a l y s i s by MS showed t h a t not l e s s than 99 percent conversion had occurred. 3

2

Expanded Scale Plasma Reactor The approach taken i n the study was to o b t a i n maximum throughput, w i t h the o b j e c t i v e of a c h i e v i n g low process c o s t s . G e n e r a l l y , the t o t a l microwave power a v a i l a b l e , 4.2 to 4.7 kW, was a p p l i e d to the discharge. This allowed the plasma t o operate at h i g h e r p r e s s u r e s , thereby p e r m i t t i n g a maximum amount of oxygen to be used as the plasma gas f o r r e a c t i o n w i t h the p e s t i c i d e s and wastes. During the i n i t i a l r u n s , the S e r i e s A microwave power a p p l i c a ­ t o r w i t h a 2.7 l i t e r r e a c t o r v o l . was used f o r plasma decomposi­ t i o n s o f A r o c l o r No. 1242 PCB. I t was determined that the l i q u i d had been decomposed and t h a t one of the r e a c t i o n products — a b l a c k s o o t - l i k e deposit which coated the product r e c e i v e r — con­ t a i n e d l i t t l e or no PCB, as determined by i n f r a r e d spectroscopy. A f t e r a d d i t i o n a l runs were c a r r i e d out i n which feed, p r e s s u r e , and absorbed power were v a r i e d , i t became apparent t h a t the r e a c ­ t o r was too l a r g e i n volume f o r the power a v a i l a b l e . S e r i e s Β and C a p p l i c a t o r s , having r e a c t o r volumes 1.5 and 0.6 l i t e r s , respec­ t i v e l y , were e v a l u a t e d i n t u r n . The r e s u l t s are d e t a i l e d i n Table I I I and are d e s c r i b e d i n the f o l l o w i n g s e c t i o n s . M a l a t h i o n l i q u i d was drop-fed onto a porous, quartz wool bundle p o s i t i o n e d at the top power input to the plasma zone. By t h i s means, i n a mechanism s i m i l a r to that which was used i n the

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978. 360

13-25

206(0.4) 1020(2.25) 120-140

4.5 4.6

Β

C

31-62

31-88

> (b) Raschig Rings

720

45-60

>99.9999

Raschig Rings 300 35 - 6 0

4.6

C

68-58

Red Dye Mixture 15.5% Solids Aqueous Slurry

(a) Quartz (b) See text.

>99 Raschig Rings 810

30 - 70

4.6

C

38-38

Kepone 80/20 2- to 3-g Solid Discs (b)

>99 Raschig Rings None

35-50

4.2

C

99

Complete, estim. 99.99

100-120

Raschig Rings

Raschig Rings

792

792

38-36

(b)

2950(6.3)

2380(5.25) 100-120

Kepone 80/20 10?c Solids, Aqueous Slurry

4.3

4.0

Complete, estim. 99.99^ Complete, estim. 99.99

4.6

C

C

Raschig Rings

C

31-110

31-108

960

>99

Wool Plug

395

19-36

492(1.1)

4.2

Β

31-10

38-30

PMA Troysan PMA-30 Kepone 80/20 20% Methanol Solution

Troysan PMA-30

PMA

Troysan PMA-30

PCB Aroclor 1242 PCB Aroclor 1254 PMA >99

>99

Wool Plug

323

17-35

270(0.6)

4.6

Β

31-8

PCB Aroclor 1242 Solid Rings

99.9999

Wool Plug

480

28-30

480(1.1)

4.7

Β

31-46

Malathion "Cythion" ULV

.

99.9988

Wool Plug

361

28-46

504(1.1)

3.7

Β

31-16

Malathion "Cythion" ULV

_

Conversion (%)

a

Reactor Packing( )

Microwave Feed Rate [g/hr Power (lb/hr)] (kW)

Run No.

Pesticide/Waste

Applicator Series

Oxygen Gas Flow (liters/hr)

Summary of Expanded-Scale Oxygen Plasma Reactions Pressure Range (torr)

Table III.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8x4

8X8

38-8

438-14

8x8

31-110

10 x 10

8x8

31-108

38-6

8x8

Ring Size o.d. x Length (mm)

31-88

Run No.

31

31

34

45

45

16

Bed Length (cm)

13.2 to 16.0

13.2 to 18.4

13.2

13.2

13.2

8 to 16

Oxygen Flow (Standard liter/min)

130

112

115

120

120

120

Top

75

60

42

60

64

90

Bottom

Pressure (torr)

4.7

4.6

4.3

4.3

4.0

4.6

Microwave Power (kW)

8.0

6.0

4.25

6.5

5.25

2.25

Throughput (lb/hr)

CH3OH component observed at 8 lb/hr

Smanest rings in series

Largest rings in series

Repeat of 31-108

Reactor completely filled with rings

Reactor filled approximately one-half with rings

Notes

Effect of Packed Bed on PMA-30 (Phenylmercuric Acetate) Conversion in Series C Plasma System

Packing of 4 5-mm i.d. Reactor

Table IV·

to

5.

BAUJN ET AL.

Detoxification

of Pesticides

and

63

Wastes

l a b o r a t o r y - s c a l e system, l a r g e numbers o f s m a l l e r d r o p l e t s were produced w i t h i n the m a t r i x o f the wool, and p r o p e l l e d by the gas stream through the plasma. Products were S, S 0 , C 0 , CO, and H 0, p l u s a l i q u i d phosphoric a c i d . During the r e a c t i o n , d e p o s i t s o f a dark yellow-brown s u l f u r product mixed w i t h a c l e a r water-white h i g h v i s c o s i t y l i q u i d were formed which flowed s l o w l y down the s i d e s o f t h e r e a c t o r i n t o the r e c e i v e r . No carbonaceous o r o t h e r products resembling the s t a r t i n g m a t e r i a l were observed. Spectrophotometric a n a l y s i s o f the l i q u i d s from the two r e a c t i o n s gave residues of 12 ppm and 1 ppm malathion. P o l y c h l o r i n a t e d b i p h e n y l s (PCB s) y i e l d e d H C l , C 0 , CO, and H 0 as determined by MS. No C1 0 o r C0C1 was observed. There was formation o f some soot i n the product r e c e i v e r ; i n f r a r e d a n a l y ­ s i s gave no i n d i c a t i o n o however, that at throughpu the Β a p p l i c a t o r system, complete r e a c t i o n had not o c c u r r e d . T h i s was determined by i n f r a r e d a n a l y s i s o f the b l a c k t a r - l i k e l i q u i d products i n the r e c e i v e r t r a p which i n d i c a t e d the presence o f PCB s t a r t i n g m a t e r i a l . Consequently, the S e r i e s C a p p l i c a t o r was t e s t e d next to determine i t s usefulness f o r i n c r e a s i n g the l e v e l of throughput. Phenylmercuric a c e t a t e , Troysan PMA-30 s o l u t i o n , was passed through the S e r i e s C system i n s e v e r a l runs to determine the e f ­ f e c t of the shortened l e n g t h o f the a p p l i c a t o r , as w e l l as t o de­ termine the e f f e c t o f quartz plugs and r i n g s i n the r e a c t o r tube. The r e a c t i o n was considered complete i f none of the methanol com­ ponent was found by mass spectrometry i n the e f f l u e n t gas. Mass spectrometer s e n s i t i v i t y was. 2 t o 3 p a r t s per thousand f o r methanol, based on c o n t r o l runs performed i n the absence o f the plasma. The MS a n a l y s i s showed t h a t a t a throughput o f 3600 g (8 l b ) per h r , s m a l l amounts of methanol were detected i n the e f f l u e n t . This i n d i c a t e d that maximum d e t o x i f i c a t i o n o r d e s t r u c t i o n o f PMA-30 would occur at about 7 l b s / h r . The p r i n c i p a l gases o f the r e a c t i o n were C 0 , CO, and H 0. V o l a t i l e organomercurials were not detec­ ted by MS. M e t a l l i c mercury was d e p o s i t e d i n the traps downstream from the plasma. Experiments were performed t o modify the residence time o f the feed m a t e r i a l s i n the plasma zone. Quartz Raschig r i n g s were t e s t e d t o evaluate throughput under d i f f e r e n t packed bed c o n d i ­ t i o n s . For PMA-30, maximum throughput was defined as the feed r a t e which showed no methanol component i n the plasma e f f l u e n t as determined by mass spectrometer. For the Kepone runs, a commercial m i x t u r e , A l l i e d Chemical 80% powder c o n c e n t r a t e , was used as a s t a r t i n g m a t e r i a l . A p p r o x i ­ mately 200 g was converted i n t o aqueous s l u r r i e s , methanol s o l u t i o n s , and presscakes. The s o l i d presscakes were prepared by compress­ i n g 2-3 g batches i n a d i e under 1,000 p s i p r e s s u r e . The d i s c s , which r e q u i r e d a s t r o n g f i n g e r pressure t o f r a c t u r e , were p l a c e d at the top o f the Raschig r i n g area i n the plasma r e a c t o r tube before the plasma was i n i t i a t e d . I t was observed v i s u a l l y t h a t 2

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In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

64

breakdown and decomposition o f the s o l i d s occurred w i t h i n 10 t o 30 seconds, depending on the flow of oxygen and the pressure w i t h i n the r e a c t o r . S o l u t i o n s of 20% Kepone-methanol a f t e r f i l t r a t i o n to remove the c l a y p a r t i c l e s , were g r a v i t y f e d i n t o the plasma from a 250 cm buret needle-valve feed system i n which atmospheric pressure i n s t e a d o f reduced pressure was maintained over the s o l u t i o n . D i s p e r s i o n s of Kepone formed r e a d i l y and were f e d unf i l t e r e d from the same system. The gaseous r e a c t i o n products from the s o l v e n t and s l u r r y mixtures were C0 , CO, H C l , and H 0; phosgene o r c h l o r i n a t e d hydrocarbons were not detected by MS. Because o f the short 10 to 30-sec r e a c t i o n times f o r the s o l i d Kepone presscakes, mass s p e c t r o m e t r i c a n a l y s i s o f the gaseous e f f l u e n t s were not performed. Instead, the c l a y support powders which passed through the r e a c t o r were c o l l e c t e d from the r e c e i v e r and analyzed b hexachlorobenzene was detecte conversions were estimated at b e t t e r than 99%. Because of the l i m i t e d q u a n t i t y o f the s t a r t i n g m a t e r i a l , the r e a c t i o n s were not maximized w i t h respect t o throughput. A p o l y a r o m a t i c dye composition comprised of two polyaromatic dyes, sucrose, carbon b l a c k , and s i l i c a , which make up U. S. Navy MK 13 Mod 0 Marine Smoke and I l l u m i n a t i o n S i g n a l , was introduced i n t o the plasma as a s o l v e n t s o l u t i o n and as an aqueous d i s p e r s i o n . The dye components were 55.4% xylene azo-ft-naphthol and 18.9% 1-methylaminoanthraquinone. The KC10 oxidant was o m i t t e d from the e v a l u a t i o n i n t h i s s e r i e s . For the dye-solvent s o l u t i o n , a 15% s o l i d s methyl e t h y l ketone (MEK) mixture was decomposed. A f t e r the r e a c t i o n , there-were no red coloration© o r r e s i d u e s v i s i b l e below the r e a c t o r . However, because the MEK oxygen demand would prevent development o f a h i g h throughput, an aqueous v e h i c l e was t e s t e d f o r use as part of the feed system. A l s o , s i n c e the red dye components as a mixture were e s s e n t i a l l y hydrophobic, an ethylene oxide nonylphenol s u r f a c t a n t , TEC 1216E (TEC Chemical Co., Monterey Park, CA) was u t i l i z e d to y i e l d a f t e r f i l t r a t i o n , a 15.5% h y d r o p h i l i c s l u r r y , d e n s i t y 1.03 g/cm . The s l u r r y was added at r a t e s from 2 to 8 cm /min. The r e a c t i o n s were not maximized because, o f l i m i t a t i o n s i n s t a r t i n g m a t e r i a l supply, as was the case f o r Kepone. Based on wt%, the s o l i d r e s i d u e measured l e s s than 0.2% i n the r e c e i v e r t r a p s , or >99.8% convers i o n to gaseous products. Based on wt% of s t a r t i n g m a t e r i a l , l e s s than 0.2% s o l i d r e s i due passed through the r e a c t o r , or 99.8% conversion t o gaseous products. S p e c t r o p h o t o m e t r y comparisons i n the v i s i b l e r e g i o n o f a methylene d i c h l o r i d e s o l u t i o n of the unknown s o l i d , and known concentrations of the i n i t i a l dye mixture i n the same s o l v e n t i n d i c a t e d t h a t not more than 5 ppm of the dyes had passed through the plasma. P o l y a r o m a t i c hydrocarbons were not detected above 2 ppm u s i n g UV f l u o r e s c e n c e , i n f r a r e d and UV a b s o r p t i o n s p e c t r o photometry, and GC/MS. The <0.2% reddish-brown r e s i d u e showed v i a IR a b s o r p t i o n and GC/MS, the a d d i t i o n a l presence of d i o c t y l 3

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In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

5.

Detoxification

BAHJN ET AL.

of Pesticides

es

and Wastes

p h t h a l a t e , s i l i c o n e s , and benzene t r a c e s which probably entered the a n a l y t i c a l samples during the C H C 1 washing o f the traps and connective t u b i n g , 2

2

DISCUSSION Chemistry o f Plasma Decomposition Reactions In g e n e r a l , the decomposition o f o r g a n i c m a t e r i a l s , such as p e s t i c i d e s , c h l o r i n a t e d wastes, e t c . , w i l l encompass a l a r g e num­ ber o f complex r e a c t i o n s . The primary step i n each instance i n ­ volves c o l l i s i o n s between the compound and e i t h e r f r e e e l e c t r o n s or r e a c t i v e species produced by the a c t i o n o f the discharge on t h e reactant gas. Through the a c t i o n o f e l e c t r o n c o l l i s i o n s w i t h other s p e c i e s , f r e e r a d i c a l ganic compounds. Thes ary products. When oxygen i s u t i l i z e d as the reactant gas i n the plasma, atomic oxygen becomes the primary r e a c t i v e species which r a p i d l y o x i d i z e s the o r g a n i c compounds introduced i n t o the discharge. I n a d d i t i o n , t h e l a r g e numbers o f e n e r g e t i c f r e e e l e c t r o n s c o n t i n u a l l y bombard the compounds, and any remaining organic components w i l l be broken up i n t o s m a l l e r f r e e r a d i c a l fragments, which r a p i d l y react w i t h the oxygen present. The f r e e e l e c t r o n s may a l s o c o l l i d e w i t h the CO2 produced r e s u l t i n g i n d i s s o c i a t i o n t o CO and oxygen atoms (j8). The carbon monoxide can react w i t h other oxygen species t o reform the carbon d i o x i d e . Thus, an e q u i l i b r i u m c o n c e n t r a t i o n o f CO and C 0 may be present under c o n d i t i o n s o f complete o x i d a t i v e conversion. In the malathion-oxygen r e a c t i o n , complete o x i d a t i o n appears to have occurred i n the l a b o r a t o r y system y i e l d i n g c o l o r l e s s gases, S0 , C 0 , CO, and H 0 and metaphosphoric a c i d . I n the S e r i e s Β r e a c t o r , there was no s i g n i f i c a n t d i f f e r e n c e i n e f f i c i e n c y , except f o r t h e formation o f some y e l l o w , incompletely converted, s u l f u r l i k e s o l i d s . Disappearance o f the s o l i d s would be expected i n t h e Series C r e a c t o r , w i t h i t s improved packing, r e s u l t i n g i n an i n ­ crease i n S0 , H 0, e t c . For PCB-oxygen, r e a c t i o n s i n the l a b o r a t o r y system y i e l d e d C l , HCl, C 0 , CO, H 0, minor amounts o f C1 0 and C0C1 , and a s o o t - l i k e product i n t h e r e c e i v e r . I t appears probably t h a t t h e C1 0 (9) and/or C l (10) reacted w i t h some o f the CO t o produce the observed C0C1 . I n the expanded s c a l e S e r i e s Β r e a c t o r , no C1 0 o r C0C1 was observed, which may have r e s u l t e d from the d i f ­ f e r i n g r e a c t o r c o n d i t i o n s . Further o p t i m i z a t i o n i n the S e r i e s C system should r e s u l t i n the disappearance o f the soot, and forma­ t i o n o f increased amounts o f H C l , C 0 , CO, and H2O. With regard t o the observed d i f f e r e n c e s i n throughput o f t h e Series Β and C r e a c t o r s , the v a r i a t i o n s may be r e l a t e d to the power d e n s i t i e s which d i f f e r f o r each r e a c t o r . The Β r e a c t o r , w i t h a volume o f 1.5 l i t e r s , e x c l u s i v e o f packing, produced a maxi­ mum power d e n s i t y o f 3.1 watts/cm , as c a l c u l a t e d from run 31-46, 2

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In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

66

DISPOSAL AND

DECONTAMINATION OF PESTICIDES

whereas the C r e a c t o r , w i t h a 0.6 l i t e r volume, developed 7.1 watts/cm i n run 31-110. The greater power per u n i t volume i n the l a t t e r system would r e s u l t i n a d d i t i o n a l c a p a c i t y f o r m a i n t a i n i n g the oxygen discharge at increased pressures, thereby p e r m i t t i n g greater q u a n t i t i e s of organic compounds to be decomposed w i t h i n the plasma. In the l a b o r a t o r y d e t o x i f i c a t i o n of methyl bromide, i n a d d i t i o n to CO2» CO, H2O, HBr, and Br2, minor amounts of yellow-brown products, probably BrÛ2 and/or B^O, were observed i n the LN t r a p s . The bromine oxides are not s t a b l e at room temperature (11) and would be found o n l y i n r e a c t o r systems t h a t u t i l i z e t h i s type of trap. For phenylmercuric acetate-oxygen, the formation of m e t a l l i c mercury i n both l a b o r a t o r p l a i n e d by p o s t u l a t i n g t i o n , f o l l o w e d by i t s decomposition or d i s s o c i a t i o n between 440° and 610°C (12). O x i d a t i o n of the methanol s o l v e n t would be expected to f o l l o w the u s u a l mechanism to CO2, CO, and H2O. For Kepone-oxygen, the plasma r e a c t i o n products of 20% Keponemethanol s o l u t i o n s i n the expanded s c a l e system y i e l d e d oxides of carbon, water, and h y d r o c h l o r i c a c i d , and may be considered to have been completely o x i d i z e d . Reactions of CI2, produced from the o x i d a t i o n of the Kepone molecule, would be expected to r e a c t w i t h the H2O d e r i v e d from the o x i d a t i o n o f methanol, r e s u l t i n g i n HCl and HC10; the l a t t e r , being u n s t a b l e , would decompose to HCl and oxygen. In an experiment which i n v o l v e d a Kepone s l u r r y exposed to the discharge i n the absence of an oxygen flow, the r e s u l t a n t s u c c e s s f u l conversion of the p e s t i c i d e can be r e l a t e d to the formation o f , and subsequent r e a c t i o n w i t h , a water o r steam plasma (13) d e r i v e d from the aqueous component of the mixture. In both plasma r e a c t i o n s , the products were e s s e n t i a l l y the same. For the polyaromatic dye-oxygen system, the components o f the mixture reacted to form gases and <0.2% s o l i d r e s i d u e . Very l i t t l e , i f any, dye s t a r t i n g m a t e r i a l s and no s i g n i f i c a n t p o l y a r o matic hydrocarbons (PAH) were detected. Since PAH has been found i n a i r o x i d a t i o n products d e r i v e d from these m a t e r i a l s (14), a s i g n i f i c a n t advantage would appear to d e r i v e from the discharge process. D i f f e r e n c e s i n oxygen demand can be expected f o r the v a r i o u s p e s t i c i d e s and wastes as the r e s u l t of d i f f e r e n c e s i n molecular composition, r e l a t e d p r i n c i p a l l y to the number o f hydrogen atoms i n the molecule. For example, Kepone, CIQCIIOO» w i l l r e q u i r e s i g n i f i c a n t l y l e s s oxygen than PCB, A r o c l o r 1254, average composition 1 2 5 5 » f o r conversion to C02 and CO. A l s o , the use of s o l v e n t s , such as MEK, as v e h i c l e s t o t r a n s p o r t the p e s t i c i d e s i n t o the plasma, w i l l r e s u l t i n consumption o f s i g n i f i c a n t amounts o f oxygen. Therefore, unless s o l v e n t s are part of the o r i g i n a l mixture to be d e t o x i f i e d , the a d d i t i o n of these m a t e r i a l s f o r reasons of convenience i n feed o r h a n d l i n g w i l l be d e t r i m e n t a l to the overa l l throughput. 3

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In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

5.

Detoxification of Pesticides and Wastes

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67

When malathion o r methyl bromide reacted i n an argon plasma, the products were s i m i l a r to those observed i n the e a r l i e r gas r e a c t i o n s . Some o f the s u l f u r i n malathion, f o r example, appeared to form organic mercaptans o r s u l f i d e s , r a t h e r than simple molec u l e s , such as H S o r S0 » Thus, when argon i s used as a c a r r i e r gas, the wide range of p o s s i b l e products would preclude the format i o n of compounds o f low t o x i c i t y on a c o n s i s t e n t b a s i s . However, i n an oxygen plasma, the r e s u l t a n t complete o x i d a t i o n does permit an accurate p r e d i c t i o n o f the product stream and i t s l e v e l of toxicity. 2

2

Process Costs C a l c u l a t e d f o r PMA-30 For r e a c t i o n s i n the expanded s c a l e system, e l e c t r i c a l power and oxygen costs were determine put. E l e c t r i c a l consumptio wattmeter through which a l l e l e c t r i c a l equipment was routed. The data are presented i n Table V. At 6.5 l b / h r , as d e t a i l e d i n run no. 31-110, approximately $0.08/lb f o r t o t a l oxygen and e l e c t r i c a l costs was c a l c u l a t e d . For the determination of process c o s t s f o r p r o j e c t e d f u t u r e 50 to 100 l b / h r plasma systems, an accurate assessment i s d i f f i c u l t . However, where the o b j e c t i s t o show the economic v i a b i l i t y of the approach, i t i s p o s s i b l e to c a l c u l a t e values which can be d e r i v e d from known process v a r i a b l e s , and estimated oxygen, e l e c t r i c a l , and r e l a t e d c o s t s . The m a t e r i a l chosen f o r the c a l c u l a t i o n was phenylmercuric acetate (PMA), f i r s t , because i t was considered r e f r a c t o r y o r d i f f i c u l t to decompose s a f e l y and completely and, second, because i t had the p o t e n t i a l f o r recovery o f the mercury values i n the m e t a l l i c state. The f o l l o w i n g assumptions are l i s t e d as p a r t of the estimated costs. Capital costs: E l e c t r i c a l costs: L i q u i d oxygen costs : Labor c o s t s : Credit f o r m e t a l l i c mercury

$100,000 per u n i t , 2 u n i t s i n use $0.015 kWh, i n d u s t r i a l r a t e $0.005/SCF, l a r g e volume usage Add $3,000/hr, storage f e e . $9/hr, one-man o p e r a t i o n of two automated u n i t s $1.50/lb

A standard 330-day/yr, 3 - s h i f t o p e r a t i o n i s used. Throughput i s 50 l b / h r per u n i t , o r 792,000 l b / y r . The process v a r i a b l e s r e l a t e d to PMA-30 on a per-pound b a s i s were f o r oxygen, 4.3 SCF, and e l e c t r i c l i n e power, 1.6 kWh, obtained from run no. 31-110, which was the h i g h e s t complete r e a c t i o n throughput determined e x p e r i m e n t a l l y . The c a l c u l a t e d costs are as f o l l o w s :

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4.0

4.3

31-108

31-110

(b)

Electrical,

792(28)

792(28)

960(34)

Oxygen Flow [Std l i t e r A r (SCFH)]

industrial rate

2950(6.5)

2380(5.25)

1020(2.25)

Feed Rate [gAr (IbAr)]

0.052

0.064

0.18

Gas C o s t ($A>) ( a )

1.6

1.9

4.7

Electrical Energy Consumed (kWh/lb)

0.032

0.038

0.094

Electrical Energy Φ) Cost ($A>)

Electrical and Oxygen Costs for PMA-30 Oxygen Plasma Reactions

$0.02AWh,

(a) O2, $0.012/SCF

4.6

31-88

Run No.

Microwave Power (kW)

Table V.

0.08

0.10

0.27

Total Cost ($/lb)

5.

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69

V a r i a b l e Costs Operating Labor Oxygen Electricity Maintenance (4% o f Investment)

$71,280 20,028 19,008 8,000

F i x e d Costs C a p i t a l Recovery (10 yr-7%) Taxes and Insurance (2%) T o t a l Annual Costs Cost p e r Pound Treated

28,480 4,000 150,796 $0.19

Based on recovery and s a l of $0.085/lb i s d e r i v e d Process Development As the r e s u l t o f accomplishments i n t h e i n i t i a l s c a l e u p , the design and c o n s t r u c t i o n o f h i g h e r c a p a c i t y equipment and components has been continued. This i n c l u d e s p o s i t i v e displacement feed techniques f o r s o l i d s as w e l l as l i q u i d s and s l u r r i e s , a d d i t i o n a l microwave power, up t o 15 kW, to generate an estimated throughput of 10 t o 30 l b s / h r , and a high-power a p p l i c a t o r f o r t r a n s f e r o f the i n c r e a s e d microwave energy t o the r e a c t o r tube. C o o l i n g traps are r e q u i r e d , e s p e c i a l l y f o r product s e p a r a t i o n and condensation. Based i n p a r t on i t s c o m p a t i b i l i t y w i t h wet gases, a water r i n g s e a l vacuum pump system has been designed. A n a l y t i c a l instrumentat i o n has been extended t o i n c l u d e an automatic gas chromatographic mass spectrometer-data system f o r d e t e c t i o n o f t r a c e s of p o t e n t i a l l y t o x i c m a t e r i a l s i n the ppm range. As part o f the e v a l u a t i o n , data w i l l be c o l l e c t e d on e l e c t r i c a l power and oxygen consumed, percent conversion, and mass throughput f o r oxygen plasma systems. These w i l l be obtained i n order to prepare an economic comparison between the microwave plasma process, i n c i n e r a t i o n , and o t h e r conventional technologies. Future U t i l i z a t i o n The microwave plasma system, as now e n v i s i o n e d , w i l l be p o r t able t o , o r may be s i t u a t e d a t , s i t e s where h i g h l y t o x i c m a t e r i a l s are consumed, s t o r e d , o r manufactured, i n c l u d i n g h o s p i t a l s , u n i v e r s i t i e s , research f a c i l i t i e s , a g r i c u l t u r a l s t a t i o n s , as w e l l as chemical and i n d u s t r i a l areas. The p e s t i c i d e s and hazardous wastes which can be t r e a t e d by microwave plasma p r o c e s s i n g i n c l u d e gases, pure organic l i q u i d s , s o l u t i o n s , s l u r r i e s , pure s o l i d s , and s o l i d s mixed w i t h i n o r g a n i c components. These a r e s t o r e d i n drums, c a n n i s t e r s , b o t t l e s , i n d i s p e r s i o n , and i n s e t t l e d - o u t form, both pumpaMe and i n d i f f i c u L t - t o - p u m p c o n s i s t e n c y , and t h e r e f o r e cover the f u l l range o f m a t e r i a l s and m a t e r i a l s h a n d l i n g t e c h n o l o g i e s . R e l a t i v e t o l a r g e i n c i n e r a t o r equipment, such as on t h e s h i p Vulcanus, the microwave system i s , o f course, s m a l l . I t should be

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noted, however, that t r a n s p o r t a t i o n o f hazardous wastes across s t a t e l i n e s may i n v o l v e l e g a l , p o l i t i c a l , and s c i e n t i f i c questions which have yet t o be r e s o l v e d . CONCLUSIONS Microwave plasma technology has been shown t o be h i g h l y e f f e c t i v e f o r the d e t o x i f i c a t i o n / d e s t r u c t i o n o f hazardous o r g a n i c wastes. T o x i c compounds and wastes o f current i n t e r e s t were decomposed, and the r e a c t i o n products i d e n t i f i e d t o estimate t h e i r t o x i c i t y , and t o determine the p o t e n t i a l f o r recovery o f u s e f u l m a t e r i a l s . The study r e s u l t e d i n an expansion from 1 - 5 g up t o 3 kg (7 l b ) per h r i n throughput. With regard to oxyge system, the products wer t o x i c by-products were formed which could not be t r e a t e d w i t h c a u s t i c . Of the systems t o which h i g h s e n s i t i v i t y a n a l y t i c a l techniques were a p p l i e d , e.g., malathion and polyaromatic dyes, very l i t t l e o r no s t a r t i n g m a t e r i a l was detected i n the r e s i d u e s , and no s i g n i f i c a n t t o x i c / c a r c i n o g e n i c substances were found i n the e f f l u e n t s . The p o t e n t i a l f o r resource recovery was demonstrated f o r a phenylmercuric acetate p e s t i c i d e which y i e l d e d m e t a l l i c mercury as a s a l a b l e product. The process may permit the recovery o f chemical feedstocks when a p p l i e d to other o r g a n o m e t a l l i c p e s t i cides o r wastes, which would otherwise be permanently l o s t . I n the f u t u r e , u t i l i z i n g h i g h e r power f o r the r e a c t o r , scaleup t o a p i l o t l e v e l throughput o f 10 to 30 l b s / h r w i l l be t e s t e d . Further expansion t o 50 - 100 l b s / h r i s e n v i s i o n e d as f e a s i b l e w i t h c u r rent technology.

ABSTRACT Detoxification of pesticides and hazardous wastes has been performed successfully in a microwave-induced oxygen plasma. Materials were passed through a laboratory-size reactor to determine conversion efficiencies and product identities. Construction of an expanded-volume system followed which resulted in an increase in throughput from 1 - 5 g/hr for the laboratory unit to 450 3200 g (1 to 7 lb) per hr in the larger system. Substances treated were PCB's, phenylmercuric acetate (PMA) solution, methyl bromide, malathion, a polyaromatic dye mixture, and Kepone. Detoxification of PMA yielded metallic mercury as a salable by-product. Treatment costs were computed which included electricity, oxygen, capital equipment, and labor.

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ACKNOWLEDGMENT The work upon which t h i s p u b l i c a t i o n i s based was performed pursuant t o Contract 68-03-2190 w i t h the U. S. Environmental Pro­ t e c t i o n Agency, C i n c i n n a t i , Ohio. A d d i t i o n a l support was obtained from the Lockheed Independent Research Program. A p p r e c i a t i o n i s tendered t o Dr. Ernest L. L i t t a u e r , Lockheed P a l o A l t o Research Laboratory, and P r o f e s s o r A l e x i s T. B e l l , U n i v e r s i t y o f C a l i f o r n i a , Berkeley, f o r guidance and many v a l u a b l e suggestions.

LITERATURE CITED 1.

"Disposal of Hazardous Wastes," U.S. Environmental Protection Agency, Report to Congress

2.

Bailin, L. J., "Microwave Plasma Detoxification Process for Hazardous Wastes, Phase II, Systems Application Evaluation," Lockheed Missiles & Space Company, Inc., Contract EPA 68-032190, Cincinnati, Ohio, October 1977.

3.

McTaggart, F. Κ., "Plasma Chemistry in Chemical Discharges," Elsevier, New York, 1967.

4.

Bailin, Lionel J., Sibert, Merle Ε., Jonas, Lonard Α., and Bell, Alexis Τ., "Microwave Decomposition of Toxic Vapor Simu­ lants," Envir. Sci. & Technology, 9(3), 254-258 (1975).

5.

Bailin, L. J. and Hertzler, Barry L . , "Development of Micro­ wave Plasma Detoxification Process for Hazardous Wastes, Phase I," Lockheed Missiles & Space Company, Inc., Contract EPA 68-03-2190, Final Report, U. S. EPA-600/2-77-030, Apr 77.

6.

Millard, Μ., "Synthesis of Organic Polymer Films in Plasmas," Chapter 5, "Techniques and Application of Plasma Chemistry," Hollahan, John R., and Bell, Alexis T., Eds. 192-193, John Wiley, New York, 1975

7.

Norris, M. V., Vail, W. Α., and Averill, P. R., "Colorimetric Estimation of Malathion Residues," Agricultural and Food Chemistry., 2(11), 570-573 (1954).

8.

Brown, Lloyd C. and Bell, Alexis T., "Kinetics of the Oxida­ tion of Carbon Monoxide and the Decomposition of Carbon Diox­ ide in a Radiofrequency Electric Discharge," Ind. Eng. Chem. Fund, 13(3), 203-218 (1974).

9.

Renard, J. J. and Boker, H. I., "Chemistry of Chlorine Monox­ ide," Chem. Rev., 76, 487-508 (1976).

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10. Remy, Η., "Treatise of Inorganic Chemistry," I, 449, Elsevier, Amsterdam, 1956. 11. Ibid., 810. 12. Ibid., II, 464. 13. Kaufman, F., "Production of Atoms and Simple Radicals in Glow Discharges," in "Chemical Reactions in Electrical Discharges," Advances in Chemistry Series No. 80, 45-46, American Chemical Society, Washington, D. C., 1969. 14. Owens, E. J., and Ward, D. Μ., "A Review of the Toxicology of Colored Chemical Smokes and Colored Smoke Dyes EB-TR 74064, Edgewood Arsenal 1964; available a MARCH 24, 1978

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6 1

State of the Art Report on Pesticide Disposal Research RALPH R. WILKINSON, EDWARD W. LAWLESS, ALFRED F. MEINERS, THOMAS L. FERGUSON, GARY L. KELSO, and FRED C. HOPKINS Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 64110

The goal of this study is to review all published and other available information on the current status of pesticide disposal research with emphasis o -chemical methods, and bioconversio being presented in order to acquaint you with our contract and its preliminary findings, and to make contact with knowledgeable persons in this field to obtain additional information. The views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency (EPA). We defer in-depth discussions of Molten Salt Technology, Microwave Detoxification, Thermal Degradation, Photochemical Processes, and Catalytic Hydrodechlorination since these topics are covered by other participants at this symposium. High Temperature Incineration The most recent investigations of the incineration of pesticides include studies of several classes of compounds and of formulations as well as of pure active ingredients. In a study by Midwest Research Institute (MRI) (1975), i t was concluded that organic pesticides may be destroyed with efficiencies approaching 99.999%. EPA recommended conditions for incineration are 2 sec retention time at 1000°C. Other time-temperature combinations are possible; e.g., 1 sec at 1100°C. Excess air is required; 80 to 160% excess is recommended (Carnes and Oberacker, 1976; Ferguson et al., 1975.) 1

This study was sponsored by the Environmental P r o t e c t i o n Agency, M u n i c i p a l Environmental Research Laboratory, C i n c i n n a t i , Ohio, under Contract No. 68-03-2527. Mr. Donald A. Oberacker was the P r o j e c t O f f i c e r . 0-8412-0433-0/78/47-073-073$05.00/0 © 1978 American Chemical Society

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Environmentally hazardous emissions which must be c o n t r o l l e d p a r t i c u l a t e P2O5 and gaseous HCN, HCl, SO2, and ΝΟχ. R e c e n t l y , i n c i n e r a t i o n of Kepone® and Mirex has been i n ­ v e s t i g a t e d by the U n i v e r s i t y of Dayton Research I n s t i t u t e (UDRI) (1976) and by Midland-Ross C o r p o r a t i o n (1977). A l a b o r a t o r y s c a l e study by UDRI i n d i c a t e d that Kepone® decomposed a t 500°C i n 1 sec and Mirex a t 700°C i n 1 sec. The degree o f e f f i c i e n c y was 99.998%. Roth Kepone® and M i r e x produce intermediate deg­ r a d a t i o n products that are hazardous. For example, i n c i n e r a t i o n of Kepone® can produce hexachlorocyclopentadiene, hexachlorobenzene, and an u n i d e n t i f i e d species (Carnes, 1977a; D u v a l l and Rubey, 1976). The Midland-Ross C o r p o r a t i o Kepone® (4 kg max. sample s i z e ) from January through March 1977. A t o t a l o f 68 kg was destroyed. The i n c i n e r a t i o n temperature was 1100°C. R e t e n t i o n time was reported as 2 sec. Major decomposi­ t i o n products were CO2, H2O, and HCl w i t h traces o f hexachlorobenzene. The d r a f t r e p o r t i s not y e t a v a i l a b l e (Carnes, 1977b). The State o f V i r g i n i a r e c e n t l y a u t h o r i z e d Flood and Asso­ c i a t e s o f J a c k s o n v i l l e , F l o r i d a , t o d e s i g n an i n c i n e r a t o r to d e s t r o y 45,000 kg o f Kepone®. The d e s i g n w i l l u t i l i z e the Mid­ land-Ross C o r p o r a t i o n data base. I n c i n e r a t i o n a t sea o f o r g a n o c h l o r i n e process wastes i s being conducted by S h e l l Chemical Company i n f a c i l i t i e s i n the G u l f o f Mexico under an EPA permit. Although the wastes are not p e s t i c i d e s , the i n f o r m a t i o n gained and technology employed are d i r e c t l y a p p l i c a b l e . Organochlorine wastes were i n c i n e r a t e d a t the r a t e o f 25 m e t r i c tons/hr a t 1200 to 1350°C average flame temperature. E f f i c i e n c i e s approached 99.9%. Emissions were e s s e n t i a l l y H C l , CO2, and H2O and were discharged d i r e c t l y to the atmosphere w i t h o u t scrubbing. Marine m o n i t o r i n g surveys below the e f f l u e n t plume i n d i c a t e d no measurable increase i n organoc h l o r i n e s i n the water o r i n marine l i f e (Wastler e t a l . , 1975). S h e l l Chemical Company i s c u r r e n t l y o p e r a t i n g under a 2-1/2 year s p e c i a l permit to burn 50,000 metric tons of chemical wastes (Environmental Sciences and Technology, 1977). I n c i n e r a t i o n o f 8.7 m i l l i o n l i t e r s of H e r b i c i d e Orange con­ t a i n i n g t r a c e s o f the d i o x i n , TCDD, was accomplished d u r i n g August o f t h i s year by the Dutch i n c i n e r a t o r ship M/T Vulcanus i n the m i d - P a c i f i c Ocean approximately 120 m i l e s from Johnston I s l a n d and 1,000 m i l e s west o f the Hawaiian I s l a n d s . The U.S. EPA permit issued t o the U.S. A i r Force and Ocean Combustion S e r v i c e s , B.V. required a t l e a s t 99.9% combustion e f f i c i e n c y . are

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P r e l i m i n a r y r e s u l t s of the i n c i n e r a t i o n i n d i c a t e d a greater than 99.99% combustion e f f i c i e n c y . No detectable TCDD was found i n the i n c i n e r a t o r stack samples. The cost of the program was around $5 m i l l i o n (Kansas C i t y Times, 1977; Chemical and E n g i neering News, 1977; P e s t i c i d e and Toxic Chemical News, 1977). In summary, i n c i n e r a t i o n has been shown to be h i g h l y e f f i c i e n t (99.9%), but c a p i t a l investment can be great. Scrubbers are normally r e q u i r e d , although they are not i f i n c i n e r a t i o n i s performed at sea. Many c l a s s e s of p e s t i c i d e s and t h e i r formul a t i o n s have been examined. However, p i l o t p l a n t s c a l e demons t r a t i o n s have not been conducted f o r s e v e r a l c l a s s e s of p e s t i c i d e s i n c l u d i n g a n i l i d e s , ureas, u r a c i l s , and n i t r a t e d hydrocarbons Other c l a s s e s of p e s t i c i d e i n v e s t i g a t i n g teams. Th pesticide must be expanded. Chemical Treatment Processes Many chemical approaches have been taken to d e t o x i f y or destroy hazardous m a t e r i a l s , i n c l u d i n g p e s t i c i d e s . These approaches g e n e r a l l y i n v o l v e r a t h e r simple treatment i n s o l u t i o n w i t h a l k a l i , a c i d s , c h l o r i n e , oxygen, or h y p o c h l o r i t e , but may i n c l u d e a p p l i c a t i o n of heat and pressure. Some of these methods are capable of d e s t r o y i n g p e s t i c i d e s , e.g., a l k a l i n e h y d r o l y s i s of organophosphate compounds. Others only p a r t i a l l y degrade the a c t i v e i n g r e d i e n t and y i e l d products which are n e a r l y as t o x i c or even more t o x i c than the o r i g i n a l p e s t i c i d e . We s h a l l ment i o n only a few of these examples and i n d i c a t e t h e i r general u s e f u l n e s s , inherent shortcomings, and c u r r e n t s t a t u s . Wet O x i d a t i o n (Zimmerman Process, Zimpro®)—The p r i n c i p l e of o p e r a t i o n i s that a s o l u t i o n of any organic compound can be o x i d i z e d by a i r or oxygen i f s u f f i c i e n t heat and pressure i s a p p l i e d . Thus, a t temperatures of 150 to 340°C and 450 to 2,500 p s i g , sewage sludges w i l l be o x i d i z e d to C0 and H 0 i n 30 to 60 min. S u l f u r , n i t r o g e n , and phosphorus may remain i n s o l u t i o n as s a l t s . Heavy metals may be p r e c i p i t a t e d as s u l f a t e s , phosphates, o x i d e s , or hydroxides, or may remain i n s o l u t i o n ( A s t r o , 1977a). The extent of a c t u a l p e s t i c i d e d e s t r u c t i o n has r a r e l y been determined ; the percent r e d u c t i o n i n t o t a l organic carbon (TOC) i s given i n s t e a d . For example, s t u d i e s on DDT, 2,4-D, and pentachlorophenol (PCP) have been reported i n t h i s manner ( A s t r o , 1977a). Other s t u d i e s of the wet o x i d a t i o n process a p p l i e d to Amiben® h e r b i c i d e process wastes i n d i c a t e 88 to 99.5% d e s t r u c t i o n 2

2

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o f the a c t i v e i n g r e d i e n t ( A s t r o , 1977b; Adams et a l . , 1976). A t r a z i n e process wastes have been claimed to be 100% destroyed ( A s t r o , 1977b). Wet o x i d a t i o n c o s t s f o r p r o c e s s i n g 160,000 l i t e r s of chemical waste per day have been estimated a t $0.37/kg of a c t i v e i n g r e d i e n t destroyed and a c a p i t a l investment of $2.2 m i l l i o n (Adams et a l . , 1976). Wet o x i d a t i o n has not been demonstrated to be w i d e l y app l i c a b l e to p e s t i c i d e s . This i s p r i m a r i l y true because of the lack o f q u a n t i t a t i v e a n a l y t i c a l data f o r the a c t i v e i n g r e d i e n t s ; merely monitoring the TOC r e d u c t i o n i s inadequate. Secondly, o n l y two c l a s s e s of p e s t i c i d e s have been examined: c h l o r i n a t e d hydrocarbons and t r i a z i n e s c i d e d i s p o s a l a p p l i c a t i o n s f o r wet o x i d a t i o n i s yet to be d e v e l oped. C h l o r o l y s i s — E x h a u s t i v e c h l o r i n a t i o n as a method of d i s posing of p e s t i c i d e s and other chemical wastes has been suggested a t l e a s t s i n c e 1974 i n the chemical press (Environmental Science and Technology, 1974). Two U.S. patents d e s c r i b i n g b a s i c improvements i n c h l o r i n a t i o n appeared i n 1972 ( K r e k e l e r e t a l . , 1972a,b). A r e c e n t study f o r the E P A - - I n d u s t r i a l Environmental Research Laboratory, Research T r i a n g l e P a r k — h a s assessed the p o t e n t i a l u s e f u l n e s s and economics of c h l o r o l y s i s to d e s t r o y p e s t i c i d e s and other chlorohydrocarbon wastes ( S h i v e r , 1976). A follow-up r e p o r t , i n c l u d i n g process d e t a i l s and e n g i n e e r i n g cost e s t i m a t e s , i s c u r r e n t l y i n the d r a f t stage (Des R o s i e r s , 1977). Depending on the type of feedstock ( a l i p h a t i c or aromatic) exhaustive c h l o r i n a t i o n takes place over a range of pressures and temperatures. According to a new process developed by Farbwerke Hoechst AG, F r a n k f u r t / M a i n , Germany, hydrocarbons and t h e i r oxygenated or c h l o r i n a t e d d e r i v a t i v e s are completely conv e r t e d to CCI4, COClg, and HCl a t pressures up to 240 a t . and temperatures up to 620°C ( K r e k e l e r et a l . , 1975). P e s t i c i d e s and organic wastes t h a t c o n t a i n s u l f u r , n i t r o g e n , and/or phosphorus may have adverse e f f e c t s on the c h l o r o l y s i s process. Thus, the presence of s u l f u r - b e a r i n g p e s t i c i d e s i n excess of 25 ppm s u l f u r i n the hydrocarbon feedstream may cause severe c o r r o s i o n of the n i c k e l tube c a t a l y t i c r e a c t o r ( S h i v e r , 1976). There i s some q u e s t i o n as to whether NCI3 and PCI3 or PCI5 would be formed i n a p p l y i n g the c h l o r o l y s i s process to Nand P - c o n t a i n i n g p e s t i c i d e s , and o f the hazards i f these produ c t s were formed. F u r t h e r research needs to be performed to o b t a i n i n f o r m a t i o n on these p o i n t s .

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We do not recommend c h l o r o l y s i s f o r the d i s p o s a l of organom e t a l l i c p e s t i c i d e s without c a r e f u l i n v e s t i g a t i o n and c o n t r o l ; some o f the t o x i c heavy metals (e.g., As and Hg) would form v o l a t i l e chlorides. At l e a s t one cost estimate f o r a c h l o r o l y s i s p l a n t has been made. A p l a n t c a p a c i t y to process 22,700 m e t r i c tons per year of waste hydrocarbons or chlorohydrocarbons could y i e l d from 5 to 14% r e t u r n on investment. S a l a b le products are C C I 4 , COCLj, and H C l . The c a p i t a l investment f o r primary and a u x i l i a r y f a c i l i t i e s may be as h i g h as $40 to $45 m i l l i o n . The cost to d e s t r o y the c h l o rohydrocarbon may be as h i g h as $0.97/kg ( S h i v e r , 1976). On the b a s i s o f l i m i t e d demonstrations of c h l o r o l y s i s of p e s t i c i d e s we can only i n d i c a t c i d e s . Recently c a n c e l l e greatly pesticide those i n the h i g h l y c h l o r i n a t e d category and those based on d i e n e s t r u c t u r e s . F o r t u n a t e l y , these are the best candidates f o r c h l o rolysis. O z o n e / U l t r a v i o l e t (UV) I r r a d i a t i o n — H o u s t o n Research, I n c . , has developed a method of d e s t r o y i n g or d e t o x i f y i n g hazardous chemicals i n s o l u t i o n , i n c l u d i n g heavy metal cyanides and p e s t i c i d e s , u t i l i z i n g a combination of ozonation and UV i r r a d i a t i o n . The technique i n v o l v e s r a t h e r simple apparatus: a r e a c t o r v e s s e l , an ozone generator, a gas d i f f u s e r or sparger, a mixer, and a high-pressure mercury-vapor lamp. P e s t i c i d e s that have been r e duced to l e v e l s of < 0.5 ppm from an i n i t i a l s o l u t i o n concentrat i o n of — 50 ppm i n c l u d e : PCP, malathion, Vapam® and Baygon®. DDT has been reduced from 58 ppb i n s o l u t i o n to < 0.5 ppb i n 90 min (Mauk et a l . , 1976). To date o n l y two r e a c t o r s , 10 and 21 l i t e r volumes, have been t e s t e d ; both are considered to be bench-scale models. Houston Research, Inc., i n d i c a t e s , however, that scale-up to much l a r g e r s i z e s should be r e a d i l y accomplished. Only three c l a s s e s of p e s t i c i d e s have been s y s t e m a t i c a l l y i n v e s t i g a t e d u s i n g d e s t r u c t i o n by ozonation/UV i r r a d i a t i o n : c h l o r i n a t e d hydrocarbons (DDT and PCP); organophosphate compounds (malathion); and, carbamates (Baygon® and Vapam®). For each of these p e s t i c i d e s the experimental parameters have been optimized to y i e l d "complete d e s t r u c t i o n , " i . e . , 99+%, i n the s h o r t e s t p o s s i b l e time. Thus, s o l u t i o n temperature, i n t e n s i t y of i r r a d i a t i o n , ozonation f l u x , and s t i r r i n g r a t e are a l l important experimental parameters. Other p e s t i c i d e c l a s s e s have not been i n v e s t i g a t e d by t h i s process to the best of our knowledge.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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DECONTAMINATION OF PESTICIDES

No cost estimates are a v a i l a b l e f o r t h i s process. Principal c a p i t a l equipment c o s t s i n c l u d e the r e a c t o r , the ozone generator, power supply and c o n t r o l s , and the UV i l l u m i n a t i o n source and power supply. P r i n c i p a l o p e r a t i n g c o s t s i n c l u d e e l e c t r i c a l energy and l a b o r . B i o d e t o x i f i c a t i o n of P e s t i c i d e s Much of the research to date on p e s t i c i d e biodégradation has focused on l o s s of d e s i r e d t o x i c i t y under a g r i c u l t u r a l a p p l i c a t i o n and r u n o f f c o n d i t i o n s . L i t t l e of t h i s work provides v a l u a b l e carry-over i n the realm of p e s t i c i d e d i s p o s a l . The l a r g e number of v a r i a b l e s i n v o l v e d i research approach and r e s u l Some very important l a b o r a t o r y s c a l e work has been performed by Dr. Douglas Munnecke, formerly w i t h the EPA, now i n West Germany (MUnnecke, 1977; Munnecke and Hsieh, 1975). Emuls i f i a b l e p a r a t h i o n was the s o l e carbon and energy source f o r a mixed b a c t e r i a l c u l t u r e grown from sewage, s o i l , and water samples. A f t e r a 36-day a d a p t a t i o n p e r i o d , the c u l t u r e e x h i b i t e d maximum growth i n a s o l u t i o n c o n t a i n i n g 5,000 ppm p a r a t h i o n and showed o n l y a s l i g h t decrease i n a c t i v i t y when the p a r a t h i o n concentrat i o n was r a i s e d to 10,000 ppm. This higher l e v e l represents an approximation of the c o n c e n t r a t i o n s present i n wash s o l u t i o n s from p e s t i c i d e c o n t a i n e r s and a i r c r a f t spray tanks (Hsieh et a l . , 1972). Three d i f f e r e n t biochemical pathways were used by the c u l t u r e to a t t a c k the e m u l s i f i a b l e p a r a t h i o n under aerobic or low oxygen c o n d i t i o n s . The a c t i v e organisms included f i v e subc l a s s e s o f f l u o r e s c e n t pseudomonads, p l u s species of Brevibacterium, Azotomonas, and Xanthomonas. The maximum c o n c e n t r a t i o n r a t e o f degradation was 50 mg p a r a t h i o n per l i t e r per hr. The success of the c u l t u r e was, i n p a r t , because of the production of the enzyme, p a r a t h i o n h y d r o l a s e . This enzyme was separated from the a c t i v e c e l l s and found to be t o l e r a n t of high temperatures (55°C f o r 10 min without d e a c t i v a t i o n ) and s u i t a b l e for s u b s t r a t e i n d u c t i o n . The b a c t e r i a l mixed c u l t u r e demonstrated the a b i l i t y to hydrolyze seven of e i g h t t e s t e d organophosphate i n s e c t i c i d e s . Only Lebaycid®, w i t h three d i f f e r e n t f u n c t i o n a l groups, was not hydrolyzed. Depending on the p e s t i c i d e , b i o chemical d e t o x i f i c a t i o n r a t e s when using 20 mg p r o t e i n / l i t e r , were 1 to 300 times f a s t e r than i n chemical d e t o x i f i c a t i o n procedures using 0.1N NaOH.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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The s i g n i f i c a n c e o f t h i s s e r i e s o f experiments may be sum­ marized as f o l l o w s : (a) a t o x i c organophosphate i n s e c t i c i d e , p a r a t h i o n , was s u c c e s s f u l l y biodegraded to simpler phosphoric a c i d s and phenols, (b) the m i c r o b i a l c u l t u r e produced was a b l e to degrade s i x a d d i t i o n a l organophosphate p e s t i c i d e s , and (c) the enzyme which was capable o f h y d r o l y z i n g these b i o c i d e s was i s o l a t e d and found to be s t a b l e o u t s i d e the parent c e l l . Dr. Munnecke i s c u r r e n t l y working w i t h Bayer Farbenfabriken of Leverkusen, West Germany to determine the f e a s i b i l i t y o f u s i n g immobilized o r free enzymes f o r the d e t o x i f i c a t i o n o f i n d u s t r i a l p e s t i c i d e p r o d u c t i o n wastes. P r e l i m i n a r y r e s u l t s show that free enzymes can be used t o d e t o x i f y p a r a t h i o n i n formulations and p r o d u c t i o containers. Current research i s i n progress t o s c a l e up to 40,000 l i t e r s o f batch fermentations o f mixed b a c t e r i a l c u l t u r e s . Towards the end o f t h i s summer Munnecke hopes t o begin p i l o t s t u d i e s f o r d e t o x i f i c a t i o n o f 1,000 l i t e r s per hour o f p e s t i ­ c i d e production wastewater. In c l o s i n g t h i s address we wish to note that the MRI team intends to v i s i t s e v e r a l s e l e c t e d s i t e s t o o b t a i n f i r s t - h a n d i n ­ formation on the s t a t e o f the a r t o f p e s t i c i d e d i s p o s a l r e s e a r c h .

Literature Cited 1. Carnes, R. Α., and D. A. Oberacker. Pesticide Incineration. (1976) U.S. Environmental Protection Agency, Municipal Environmental Research Laboratory. 2. Ferguson, T. L., F. J. Bergman, G. R. Cooper, R. T. Li, and F. I. Honea. Determination of Incinerator Operating Con­ ditions Necessary for Safe Disposal of Pesticides. (1975) EPA-600/2-75-041. 3. Carnes, R. A. Thermal Degradation of Kepone®. (1977a) U.S. Environmental Protection Agency, Municipal Environmental Research Laboratory. 4. Duvall, D. S., and W. A. Rubey. Laboratory Evaluation of High Temperature Destruction of Kepone® and Related Pesti­ cides, University of Dayton Research Institute. (1976) Technical Report UDRI-TR-76-21. 5. Carnes, R. A. EPA/MERL, Cincinnati. (1977b) Personal com­ munication to R. R. Wilkinson. 6. Wastler, T. A., C. K. Offutt, C. K. Fitzsimmons, and P. E. Des Rosiers. Disposal of Organochlorine Wastes by Incinera­ tion of Sea. (1975) NTIS PB-253,979. 7. Environmental Sciences and Technology. (1977) 11(3): p. 236-237. In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

80

8. 9. 10. 11. 12. 13.

14. 15. 16. 17.

18.

19. 20. 21.

22.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

The Kansas City Times. (September 8, 1977) p. 13A. Chemical and Engineering News. (September 12, 1977) p. 20. Pesticide and Toxic Material News. (August 10, 1977) p. 33. Astro Metallurgical Corporation. Wooster, Ohio. Summary of Waste Examples Reacted by Wet Oxidation Through 1976. (1977a) Form No. WT-77-3. Astro Metallurgical Corporation. Astrol™ Wet Oxidation Waste Treatment Systems. (1977b) Form No. WT-77-1. Adams, J. T., Ν. J. Cunningham, J. C. Harris, P. L. Levins, J. L. Stauffer, and Κ. E. Thrun. Destroying Chemical Wastes in Commercial-Scale Incinerators. (1976) NTIS PB267. p. 987. Environmental Science Krekeler, H., H. Meidert, W. Riemenschneider, and L. H. Hornig. U.S. Patent No. 3,651,157 issued March 21, 1972, and U.S. Patent No. 3,676,508 issued July 11, 1972. Shiver, J. K. Converting Chlorohydrocarbon Wastes by Chlo­ rolysis. (1976) NTIS PB-259. p. 935. Des Rosiers, P. Industrial Pollution Control Division. (1977) Office of Research and Development, Environmental Protection Agency, Washington, D.C., Personal communication to R. R. Wilkinson. September. Krekeler, Η., H. Schmitz, and D. Rebhan. The High-Pressure Chlorolysis of Hydrocarbons to Carbon Tetrachloride--A New Process for the Utilization of Chlorinated Hydrocarbon Wastes. (1975) National Conference on the Management and Disposal of Residues for the Treatment of Industrial Waste­ -waters. Washington, D.C. February 3-5, 1975. Informa­ tion Transfer, Inc., Rockville, Maryland. Mauk, C. E., H. W. Prengle, Jr., and J. E. Payne. Oxidation of Pesticides by Ozone and Ultraviolet Light. (1976) NTIS AD-A028 306. Münnecke, D. M. Properties of an Immobilized PesticideHydrolyzing Enzyme. (1977) App. and Environ. Microbio. (1977) 33(3): p. 503-507. Münnecke, D. Μ., and D. P. H. Hsieh. Development of Micro­ bial Systems for the Disposal of Concentrated Pesticide Suspension. (1975) Meded. Fac. Landbuwwet. Rijksuniv. Gent. (1975) 40 (2, Pt. 2): p. 1,237-1,247. Chem. Abstr. (1976) 84, 131127d. Hsieh, D. P. H., T. E. Archer, D. M. Münnecke, and F. E. McGowan. Decontamination of Noncombustible Agricultural Pesticide Containers by Removal of Emulsifiable Parathion. (1972) Environ. Sci. Tech. (1972) 6(9): p. 826-829.

MARCH 23, 1978 In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7 Thermal Degradation of Selected Fungicides and Insecticides MAURICE V. KENNEDY Department of Biochemistry, Mississippi State University, Mississippi State, MS 39762 MILES E . H O L L O M A N Propulsion Directorate, U.S. Army Missile Command, Redstone Arsenal, A L 35809 FAY Y. HUTTO Mississippi State Chemical Laboratory, Mississippi State, MS 39762

One major problem facing agricultural leaders of today is the disposal of large quantities of waste pesticides without contamination of the environment as pesticides complicate difficult to develop a single method of disposal which can be universally employed. In the past settling ponds, ground burial, deep-well injection, and incineration have been the principal methods for disposal of chemical wastes (1). The first three procedures may not be suitable for disposal of large amounts of pesticides because they do not guarantee that the pesticides will remain at the disposal site. Pesticides may be transported over and through soil by either runoff or ground water (2). Thus, pesticide disposal by any of these methods might not only prevent future use of the disposal site for agricultural purposes but might also trigger widespread environmental pollution by these chemicals. Incineration, however, has shown promise of being an efficient means of pesticide disposal (3). Since the aim of incineration is complete destruction of the pesticide molecule, a number of factors concerning the thermal degradation of pesticides must be determined in order for this process to be fully evaluated as a possible method of pesticide disposal. The degradation temperature for each compound considered as a possible candidate for incineration must be known. Moreover, combustion of pesticides may produce a number of toxic gases (4,5). Identities of all the potential pollutant gases produced by each pesticide must, therefore, be known in order to facilitate development of a scrubber system capable of minimizing air pollution. A comprehensive investigation of pesticide combustion products must also include products of incomplete combustion which may be formed under non-optimum combustion conditions, i . e . , during an incinerator malfunction. The purpose of the present study was to provide preliminary information concerning the degradation of two fungicides and four insecticides and to identify the pollutant 0-8412-0433-0/78/47-073-081$05.00/0 © 1978 American Chemical Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

82

i d e n t i f y the p o l l u t a n t gases produced under optimum and nonoptimum c o n d i t i o n s o f p e s t i c i d e i n c i n e r a t i o n . Experimental

Section

Fungicides and I n s e c t i c i d e s . The p e s t i c i d e s used i n t h i s i n v e s t i g a t i o n were t h e two f u n g i c i d e s and four i n s e c t i c i d e s s t u d i e d under USDA Cooperative Agreement 12-14-7001-108. A n a l y t i c a l standards and commercial formulations were s u p p l i e d by the r e s p e c t i v e manufacturers o f t h e f o r m u l a t i o n s . The chemical names o f p e s t i c i d e s and the formulations used i n t h i s i n v e s t i g a t i o n a r e as f o l l o w s : Captan, N - ( t r i c h l o r o m e t h y l t h i o ) - 4 cyclohexene-1, 2dicarboximide; O r t h o c i d e ^ S O wettabl powde c o n t a i n i n 50% active ingredient Maneb, manganeou e t h y l e n e b i s d i t h i wettable powder c o n t a i n i n g 80% a c t i v e i n g r e d i e n t . Methyl P a r a t h i o n , 0_, 0- dime thy l-O^-pj-nitrophenyl phosphorothioate; l i q u i d Methyl P a r a t h i o n 4-E c o n t a i n i n g 44% a c t i v e i n g r e d i e n t . Mirex, dodecachlorooctahydro-1,3,4-metheno-lH-cyclobutal [cd]pentalene; Mirex 4 c o n t a i n i n g 0.3% a c t i v e i n g r e d i e n t ( o i l suspension on corn cob g r a n u l e s ) . Temik, 2-methyl-2-(methylthio) propionaldehyde-0(methylcarbamoy 1 ) oxime ; Temik^lOG c o n t a i n i n g 10% a c t i v e i n g r e d i e n t (10% t e m i k impregnated on corn cob g r a n u l e s ) . Toxaphene, a mixture o f c h l o r i n a t e d camphenes o f u n c e r t a i n i d e n t i t y (combined c h l o r i n e content = 67-69%); l i q u i d f o r m u l a t i o n c o n t a i n i n g 90% t e c h n i c a l toxaphene and 10% xylene. R

Fungicide and I n s e c t i c i d e A n a l y s i s . The c o n c e n t r a t i o n o f a c t i v e i n g r e d i e n t i n each p e s t i c i d e f o r m u l a t i o n was e s t a b l i s h e d by t e n determinations. The mean values obtained a r e given i n Table I . G a s - l i q u i d chromatographic procedures were used f o r captan, methyl p a r a t h i o n , mirex, and toxaphene. Maneb was analyzed by t h e carbon d i s u l f i d e e v o l u t i o n method (6) and temik by an i n f r a r e d specrtrophotometric method (_7) . The captan, methyl p a r a t h i o n , and toxaphene f o r m u l a t i o n s d i d not r e q u i r e cleanup. Captan was d i s s o l v e d i n acetone and methyl p a r a t h i o n and toxaphene i n hexane. A l i q u o t s o f these s o l u t i o n s were d i l u t e d w i t h hexane t o t h e a p p r o p r i a t e concentration for analysis. The mirex f o r m u l a t i o n r e q u i r e d t h e f o l l o w i n g cleanup procedure (8). Samples were d i s s o l v e d i n hexane and c e n t r i f u g e d t o remove t h e i n s o l u b l e m a t e r i a l s . The supernatant l i q u i d was t r a n s f e r r e d t o a beaker c o n t a i n i n g d e a c t i v a t e d f l o r i s i l and mixed w i t h t h e f l o r i s i l . The d r i e d mixture was e x t r a c t e d f i v e times w i t h petroleum ether and the combined e x t r a c t s were evaporated t o dryness. The r e s i d u e was d i s s o l v e d i n hexane f o r a n a l y s i s .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978. L

65-90

Toxaphene

90.2

10.8

WP « Wettable powder, L « liquid, CC » corn ccb support.

CC

98-100

Temik

CC

0.3

200

44.2

Decomposes at 485

37-38 L

200

80.0

WP

400

200

300

200

46.5

WP

Decomposes before melting

172-173

(°C)

Temperature of A. I. Elimination Open Crucible

Observed Active Ingredient (%)

Tvpe Of j Fo:rmulation

Mirex

Methyl Parathion

Maneb

Captan

Pesticide

Melting Point

94.2

15.8

47.9

64.7

37.0

29.2

m

Weight Loss

99.9

99.3

99.3

97.5

72.2

58.2

(-/)

Weight Loss at 1000°C

TEMPERATURES REQUIRED FOR PESTICIDE DEGRADATION IN OPEN AND CLOSED SYSTEMS

250

175

525

200

200

275

(°C)*

Initial Degradation Temperature Sealed Aroule

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DISPOSAL AND DECONTAMINATION OF PESTICIDES

A Barber-Colman 5000 s e r i e s gas chromatograph equipped w i t h a t r i t i u m e l e c t r o n capture d e t e c t o r was employed f o r these analyses. The g l a s s column, 6 f t . χ 4 mm i . d . , was packed w i t h 1.5% OV-17, 1.95% QF-1 on 100/120 mesh Chromosorb W ( 9 ) . I n j e c t o r , column, and d e t e c t o r temperatures were 210°C, 200°C, and 210OC, r e s p e c t i v e l y . The c a r r i e r gas was n i t r o g e n a t a f l o w r a t e o f 100 ml/min. Q u a n t i t a t i o n o f the captan, methyl p a r a t h i o n , and mirex chromatograms was accomplished by t h e peak h e i g h t method. The toxaphene chromatograms were q u a n t i t a t e d by determining the t o t a l area under the toxaphene peaks u s i n g a Westronics Model 222 d i s c i n t e g r a t o r . T h i s method was determined t o be 99.5% reproducible. M u f f l e Furnace Treatments a c t i v e i n g r e d i e n t was completely e l i m i n a t e d from each f o r m u l a t i o n was determined i n a m u f f l e furnace i n the f o l l o w i n g manner. Samples o f the p e s t i c i d e s were weighed i n Coors No. 0 p o r c e l a i n c r u c i b l e s and heated a t 100°C increments from 100°C t o 1000°C. Each d e t e r m i n a t i o n was conducted i n t r i p l i c a t e i n the temperature range o f 100°C t o 500°C and i n d u p l i c a t e a t the h i g h e r tempera­ t u r e s . The optimum time o f h e a t i n g f o r each p e s t i c i d e was e s t a b l i s h e d by v a r y i n g the time o f h e a t i n g a t 100°C, 500°C, and 800OC. A h e a t i n g time o f 45 min was found t o be s u f f i c i e n t t o reach a p o i n t o f no f u r t h e r r e a c t i o n . The c o o l e d samples were then analyzed f o r weight l o s s and content o f a c t i v e i n g r e d i e n t by the methods d e s c r i b e d p r e v i o u s l y . The c r i t e r i o n used f o r e l i m i n a t i o n o f t h e a c t i v e i n g r e d i e n t was no d e t e c t a b l e amount of p e s t i c i d e a t the yg/ml l e v e l o f r e s i d u e c o n c e n t r a t i o n f o r the p e s t i c i d e s analyzed by gas chromatography and the mg/ml l e v e l f o r thos analyzed by wet methods. An u n t r e a t e d sample o f the commercial f o r m u l a t i o n was analyzed as a q u a l i t y c o n t r o l sample along w i t h each group o f heated samples. Sealed Ampoule Determinations. The temperatures a t which degradation o f the a n a l y t i c a l grade p e s t i c i d e s i n i t i a t e d was determined as f o l l o w s . Samples were s e a l e d i n 10 ml ampoules and heated i n a m u f f l e furnace i n increments o f 25°C beginning a t t h e i r m e l t i n g p o i n t s and c o n t i n u i n g t o some temperature a t which degradation was confirmed. Sample s i z e s were approximately 20 mg and h e a t i n g time was 15 min a t each temperature. The c r i t e r i a used t o e s t a b l i s h the temperature a t which thermal degradation was i n i t i a t e d were the temperature a t which the i n f r a r e d spectrum d e v i a t e d from t h a t o f the u n t r e a t e d p e s t i c i d e due t o t h e disappearance o f one o r more major a b s o r p t i o n s and/or a change i n p h y s i c a l appearance o f the p e s t i c i d e . A l l i n f r a r e d s p e c t r a were o b t a i n e d u s i n g 13 mm KBr p e l l e t s o r Œ>2 o r C C I 4 s o l u t i o n s . The instrument was a Perkin-Elmer 337 g r a t i n g spectrophotometer. S p e c t r a o f the u n t r e a t e d p e s t i c i d e s were compared t o those i n the S a d t i e r Index when p o s s i b l e (10).

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7.

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Fungicides

and

Insecticides

85

P o l l u t a n t Gas A n a l y s i s . Two i n v e s t i g a t i o n s were conducted t o determine the v o l a t i l e products o f p r e s t i c i d e combustion. The f i r s t study was the experimental d e t e r m i n a t i o n o f the gaseous products formed d u r i n g h e a t i n g i n the temperature range o f 400 525°C. A n a l y t i c a l grade p e s t i c i d e s (50-100 mg) were s e a l e d i n 10 ml ampoules and heated i n a m u f f l e furnace f o r 15 minutes. I d e n t i f i c a t i o n o f the gaseous products was accomplished by a combination o f mass spectrometry and gas chromatography. The mass spectrometer was a V a r i a n Anaspect ΕΜ-600 equipped w i t h an EM 6270 gas sampling adapter. Gaseous samples were introduced w i t h the adapter a t an i n l e t temperature o f 180°C. S p e c t r a were obtained a t i o n i z i n g v o l t a g e s of 70 eV and approximately 25 eV and were i n t e r p r e t e d by u s i n g a computer program. The program l i s t e d a l l p o s s i b l e combination p e s t i c i d e which would g i v spectrum o f i t s gaseous p r o d u c t s . The most probable gas (or gases) were s e l e c t e d f o r p o s s i b l e c o n f i r m a t i o n by gas chroma­ tography u s i n g a Barber-Colman 5000 s e r i e s chromatograph equipped w i t h a thermal c o n d u c t i v i t y d e t e c t o r . A l l columns were 6 f t . by 4 mm i . d . g l a s s columns. The f o l l o w i n g packings and c o n d i t i o n s were used: (1) 80/100 mesh Deactigel? i n j e c t o r , column, and d e t e c t o r temperatures o f 120°C, 120°C, and 125°C, r e s p e c t i v e l y ? c a r r i e r gas-helium a t a f l o w r a t e o f 50 ml/min (11); (2) 10% A r o c h l o r 1232 on 40/60 mesh Chromosorb Τ; i n j e c t o r , column, and d e t e c t o r temperatures o f 30°C, 30°C, and 100°C, r e s p e c t i v e l y ? c a r r i e r gas-helium a t a f l o w r a t e o f 15 ml/min (12). The second study was the t h e o r e t i c a l p r e d i c t i o n o f the combustion products which would r e s u l t s from i n c i n e r a t i o n o f the p e s t i c i d e s under c o n d i t i o n s o f complete combustion. Complete combustion was determined by the a d d i t i o n o f s u c c e s s i v e amounts o f a i r u n t i l a p e s t i c i d e t o a i r r a t i o was o b t a i n e d a t which a s m a l l excess o f d i a t o m i c oxygen was p r e s e n t . Temperatures s t u d i e d were 1727°C and 27°C. The NASA/LEWIS Chemical E q u i l i b r u m Composition Computer Program (13) was used t o p r e d i c t the products which would be thermodynamically s t a b l e under these c o n d i t i o n s . T h i s program, which contained the thermochemical p r o p e r t i e s o f most o f the combustion products t o be expected from i n c i n e r a t i o n o f t y p i c a l halogenated hydrocarbons, was amended t o i n c l u d e the thermochemical p r o p e r t i e s o f o t h e r compounds i n d i c a t e d t o be present by the experimental d a t a . The thermodynamic d a t a were obtained from the l i t e r a t u r e (14-17). M u f f l e Furnace R e s u l t s . The temperatures a t which the a c t i v e i n g r e d i e n t was e l i m i n a t e d from each f o r m u l a t i o n and the accompanying weight l o s s e s a t these temperatures are g i v e n i n Table I . There are s e v e r a l p o s s i b l e pathways o f p e s t i c i d e l o s s d u r i n g these treatments. Three of the p o s s i b i l i t i e s are decom­ p o s i t i o n w i t h o u t v o l a t i l i z a t i o n , decomposition f o l l o w e d by v o l a t i l i z a t i o n o f the p r o d u c t s , and v o l a t i l i z a t i o n w i t h o u t decomposition. The weight l o s s e s i n d i c a t e t h a t i n each i n s t a n c e

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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DISPOSAL AND DECONTAMINATION OF PESTICIDES

c o n s i d e r a b l e q u a n t i t i e s o f gases were evolved a t these temperat u r e s . The r e s i d u e s remaining a f t e r h e a t i n g captan, methyl p a r a t h i o n and maneb a t 1000°C were f e l t t o be the r e s u l t o f the presence o f i n o r g a n i c s a l t s i n the c a r r i e r o r t o formation o f such s a l t s d u r i n g h e a t i n g . The low temperature a t which mirex could no longer be d e t e c t e d (Table I) l e d t o the s u s p i c i o n t h a t v o l a t i l i z a t i o n p r i o r t o d e g r a d a t i o n might be o c c u r r i n g i n some i n s t a n c e s . T h i s i n s e c t i c i d e has p r e v i o u s l y been r e p o r t e d t o be t h e r m a l l y s t a b l e w i t h p y r o l y s i s o c c u r r i n g o n l y about 500°C (18,19). Sealed Ampoule R e s u l t s . Since t h e r e was no way t o prevent the escape o f a v o l a t i l e product from the c r u c i b l e s , the minimum temperatures a t which d e g r a d a t i o f th p e s t i c i d e initiated was determined i n seale p o s s i b i l i t y of v o l a t i l i z a t i o p r i o degradation a l s o c o n t a i n s the r e s u l t s o f t h i s study. Comparison o f the open c r u c i b l e and sealed ampoule r e s u l t s i n d i c a t e d the i n i t i a l degradation temperatures o f maneb, methyl p a r a t h i o n , and temik were s i m i l a r t o the temperatures a t which the compounds were e l i m i n a t e d from the r e s i d u e s i n the c r u c i b l e s . No v a p o r i z a t i o n of maneb was observed i n the ampoule a t temperatures below the i n i t i a l d e g r a d a t i o n p o i n t . However, methyl p a r a t h i o n and temik were s i m i l a r t o the temperatures a t which the compounds were e l i m i n a t e d from the r e s i d u e s i n the c r u c i b l e s . No v a p o r i z a t i o n of maneb was observed i n the ampoule a t temperatures below the i n i t i a l d e g r a d a t i o n p o i n t . However, methyl p a r a t h i o n and temik v a p o r i z e d a t 125°C and 150°C r e s p e c t i v e l y , i n i t i a l degradation temperatures o f captan and mirex were c o n s i d e r a b l y h i g h e r than the temperatures a t which these compounds disappeared from the c r u c i b l e s (Table I ) . These r e s u l t s support the theory t h a t these two compounds were v o l a t i l i z e d from the c r u c i b l e p r i o r t o being degraded. Toxaphene appeared t o be degraded i n the ampoule a t a temperature c o n s i d e r a b l y lower than the temperature at which i t was no longer d e t e c t e d i n the c r u c i b l e . However, chromatograms o f toxaphene heated t o 300°C i n the open c r u c i b l e showed an a l t e r i n g o f composition as compared t o the u n t r e a t e d p e s t i c i d e , and no toxaphene was d e t e c t e d i n the r e s i d u e produced at 400°C. V o l a t i l i z a t i o n o f toxaphene i n the ampoule was noted at temperatures above 125°C. R e s u l t s o f these two s t u d i e s seem t o i n d i c a t e t h a t the i n i t i a l d e g r a d a t i o n temperatures determined i n the sealed ampoules are more a c c u r a t e than those determined i n the c r u c i b l e s because i t was i m p o s s i b l e f o r the p e s t i c i d e t o escape. P o l l u t a n t Gas A n a l y s i s . The c o n d i t i o n s used i n the l a b o r a t o r y study were intended t o s i m u l a t e an i n c i n e r a t o r m a l f u n c t i o n d u r i n g which incomplete combustion would occur as the r e s u l t o f the low temperature (400 - 525°C) and an i n s u f f i c i e n t oxygen

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7.

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supply. The h e a t i n g temperatures f o r a l l p e s t i c i d e s except mirex, were c o n s i d e r a b l y h i g h e r than the minimum degradation temperatures determined i n the sealed ampules. D i s c u s s i o n o f the gaseous combustion products i s l i m i t e d t o p o l l u t a n t gases. However, a number o f o t h e r gases were p r e s e n t i n a l l o f the m i x t u r e s . For i n s t a n c e , the mass s p e c t r a i n d i c a t e d the presence o f atmospheric n i t r o g e n , oxygen and argon as w e l l as the water vapor and carbon d i o x i d e formed as a r e s u l t o f combustion. The presence o f oxygen may have r e s u l t e d from a l e a k i n the gas sampling system. No s p e c i a l attempts were made t o c o n f i r m any o f these gases s i n c e they a r e not environmental hazards. The presence o f CO was a l s o n o t confirmed s i n c e i t i s a known product o f incomplete combustion. I n c i n e r a t i o n o f mane m a t e r i a l . The mass spectru o f which a r e g i v e n i n Table I I . From t h i s t a b l e i t i s obvious t h a t the p o l l u t a n t gases CH4, NH3, CO, and N20 cannot be p o s i ­ t i v e l y i d e n t i f i e d from the mass s p e c t r a because t h e i r masses a r e i d e n t i c a l t o t h e masses o f o t h e r species (O, OH, N 2 , and C0 # r e s p e c t i v e l y ) which were p r e s e n t i n most o f the s p e c t r a . P o l l u ­ t a n t s t e n t a t i v e l y i d e n t i f i e d from the spectrum o f the maneb gaseous product m i x t u r e were Ν 0 , COS, and C S 2 . The s u l f u r c o n t a i n i n g gases, CO2 and 20 were confirmed on the D e a c t i g e l column. The r e s i d u e remaining a f t e r h e a t i n g methyl p a r a t h i o n a t 400°C was a l s o carbonaceous. The mass spectrum o f the gaseous products was q u i t e complex, c o n t a i n i n g 29 peaks. Assignments f o r these peaks a r e presented i n Table I I . P o l l u t a n t s t e n t a t i v e l y i d e n t i f i e d were HCN, N 0 , COS, SO2, and C S 2 . The presence o f C 0 , COS, and C S was confirmed on the D e a c t i g e l column and a peak w i t h a r e t e n t i o n i d e n t i c a l t o H2S was a l s o p r e s e n t i n the chromatogram. S u l f u r d i o x i d e , however, was not confirmed and the peak a t a mass o f 64 was b e l i e v e d t o have r e s u l t e d from f u r t h e r fragmentation o f the PSO2+ fragment (mass = 9 5 ) . I n c i n e r a t i o n o f temik a t 400°C produced a carbonaceous r e s i d u e . The mass spectrum o f the gaseous products contained 20 peaks. Assignments o f these peaks a r e a l s o l i s t e d i n Table I I . P o l l u t a n t s t e n t a t i v e l y i d e n t i f i e d from the spectrum were HCN and COS. The chromatogram r e s u l t i n g from passage o f the gas m i x t u r e through the D e a c t i g e l column confirmed the presence o f CO2 and a l s o c o n t a i n e d two peaks w i t h r e t e n t i o n times i d e n t i c a l t o those of H S and C S . The c o n c e n t r a t i o n o f COS i n the gas mixture was e v i d e n t l y below t h e l i m i t o f d e t e c t i o n o f the chromatographic system. The r e s i d u e remaining a f t e r h e a t i n g captan a t 400°C was a l s o carbonaceous. The mass spectrum o f the gaseous products contained 14 peaks, assignments o f which a r e g i v e n i n Table I I I . P o l l u t a n t gases t e n t a t i v e l y i d e n t i f i e d were HCL, COS, SO2, C S 2 , and C H C I 3 . C o n f i r m a t i o n o f t h e s u l f u r - c o n t a i n i n g gases and CO2 was accomplished w i t h the D e a c t i g e l column. The chromatogram 2

2

2

2

2

2

2

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

88

DISPOSAL AND DECONTAMINATION OF PESTICIDES

TABLE II

MASS SPECTRAL DATA FOR SULFUR-CONTAINING PESTICIDES HEATED AT 400 C

14

Assignment

Confirmed by GC

*

+

Confirmed by GC

Assignment Confirmed by GC

0\ +

0H , H

2

+

NH , C H

16

18

Assignment

Ν

15

17

Temik

Methyl Parathion

Maneb AMU

NH

+

+ +' + Ο , ΚΗ , C H

N H \ CH,

2

2

+

0H ,

3

3

NH

OH *, Η\\*

+ 3

Η/

H /

0 +

4

4

+

HCN

27 28

K

0

HCN

+

N , CO +

, CO

+

+

Ν , CO

14,15

29

14.15.. + 2

+ W

+

2

2

h

2

32

Unidentified

35 40

Ar

Ar

Ar

+

C « , C H N

41

3

42

C

3 6 H

C H

43 44

5

3

C0«

Yes

C0„

N0

Yes

N 0"

2

Yes

2

+

+ ?

Yes

CO* N 0'

2

2

+

45

C H P , C0 H

46

C H P , NO

2

47

CH P , PO

+

+

48

CH Ρ , SO

49

Unidentified

2

2

+

3

+

+

3

C0 H

+

2

+

A

5

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

KENNEDY ET AL.

Fungicides and Insecticides

TABLE I I (Cont'd)

Maneb AMU

Assignment

57

—

58

—

59

—

60

COS *

Methvl Parathion Confirmed by GC

Assignment

C H P C

2

2

H

P +

2 3

Confirmed b GC

Temik Assignment Confirmed b GC

+

+

C0 N , C H S 2

2

+

2

4

CJl.P * 4

4

Yes

4

COS*

COS*

v

xes 61

—

C

2 6 »

H

P+

Cli

62

—

C

2 7 »

H

P+

C H

63

—

P0 , FS

64

—

S0

2

76

CS

CS

2

+

+ 2

Yes

+

+

Yes

+

P0 ,PS0

94

-

-

*

? 0 +

+

—

—

3

P0+

2

79

95

'2

3

PS0

+

+

CH S0 , CH S 3

H

2

S0

3

+

C

H

S

+ 2

C 6 2 » 2 6 2* 2

+ 2

Means that no peak occurred at the specified mass number.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

90

DISPOSAL AND DECONTAMINATION OF PESTICIDES

TABLE I I I

MASS SPECTRAL DATA FOR CAPTAN' AND TOXAPHENE HEATED AT 400°C AND MIREX HEATED AT 525°C Captan AMU

Assignment

+

0,

—

17 18

0H H 0

+

Toxaphene

Confirmed by GC

CH

Assignment

4

O *, C H

+ 4

Confirmed by GC

4

—

+

N ,

C0

2

+

H

2

0 +

C

2 3

H

+

+

4

N » CO*

N , CO*

+

+ A

OH*

+

H /

2

27 28

Assignment

4c

14 16

Mirex Confirmed by GC

4

2

2

32 35 36

—

Cl

Cl

+

4

HCl *

37

—

38

H C1

40

Ar

44

C0

45

—

HC1 3 7

37

Yes

+

C1

+ 4

H^Cl *

+

Ar +

Yes

2

C 0

+

C1

+

37

H C1

Ar

+

+

Yes

+

—

C0 H

+

2

4

CCI *

47 4

48

CHC1 *

49

—

60

COS*

61

—

— 37

c ci+ 4

Yes

— —

C H C1

+

C H C1

+

2

62

63

Yes

+

2

HC1 3 7

+

+

2

—

4

coci *

2

3

coci*;

C H CI*-, 2

4

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7.

KENNEDY ET AL.

Fungicides and Insecticides

91

TABLE I I I (Cont'd)

Captan AMU

Assignment

SO.

64

Confir mod by GC

Mirex Assignment Confirmed by GC

Toxaphene Assignment Confirmed by GC

Yes

65 70

C 1

3 5

72 76

cs cs V

Yes

2 3 7

C1 C1

+

Yes

ci

2

35 37 c l

c l +

Yes

2

3

78

Yes

CCI,

82 83

CHCl, 3 7

cci ci

84

+

37 + CHC1 CI

85

3 7

+

c ci

86

2

C H C1

96

2

2

2

+

coci

98

C0C1 , C H C l 2

100

37 + C0C1 CI

117

cci

4

37

+ 2

t

C H C1 C1 2

cci cci ci" 3

3

3 7

3 7

119

cci

121

cci ci

ci

123

c ci

152

cci

2 3 7

3 7

+

f

2

+ 2

+ 3

Yes

+ 4 3 7

h

154

cci ci*

156

CC1 C1+

3

37

—

2

2

Yes Yes

means that no peak occurred at the specified mass number.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2

+

DISPOSAL AND DECONTAMINATION OF PESTIODES

92

a l s o contained a peak w i t h a r e t e n t i o n time i d e n t i c a l t o t h a t of H S. Mirex was more r e s i s t a n t t o thermal degradation than any o f the o t h e r p e s t i c i d e s . Even a f t e r h e a t i n g a t 525°C the r e s i d u e was n o t carbonaceous b u t c o n s i s t e d o f l o n g , o f f - w h i t e c r y s t a l s and l i q u i d d r o p l e t s . The mass spectrum o f the gaseous products c o n s i s t e d o f 30 fragments, assignments o f which a r e presented i n Table I I I . The t o x i c gases t e n t a t i v e l y i d e n t i f i e d were i d e n t i c a l t o those r e s u l t i n g from i n c i n e r a t i o n o f mirex a t 550°C (20). C o n f i r m a t i o n o f HCl, C l f and CCI4 was accomplished w i t h t h e A r o c h l o r 1232 column and carbon d i o x i d e was confirmed on t h e D e a c t i g e l column. The r e s i d u e remaining a f t e r h e a t i n g toxaphene a t 400°C c o n s i s t e d o f a carbonaceou s o l i liquid spectrum o f t h e gaseou assignments o f which a r e g i v e n i n Table I I I . The primary p o l l u t a n t was HCl. Other p o s s i b i l i t i e s t e n t a t i v e l y i d e n t i f i e d from the spectrum were C H C1, C H C 1 , C l , C H C 1 , C0C1 , C H C 1 , and C C I 4 . V i n y l c h l o r i d e was confirmed on the D e a c t i g e l column but no C2H4CI was d e t e c t e d . The presence o f C C I 4 was confirmed on the A r o c h l o r 1232 column. The complete combustion products p r e d i c t e d by the thermodynamic c a l c u l a t i o n s a r e g i v e n i n Tables IV and V. The number o f moles o f a i r r e q u i r e d f o r complete combustion o f one mole o f p e s t i c i d e was 50 f o r mirex, 55 f o r captan, temik, and toxaphene, and 60 f o r maneb and methyl p a r a t h i o n . The h i g h e r temperature represents t h e o p e r a t i n g range o f commercial i n c i n e r a t o r s w h i l e the lower temperature s i m u l a t e s the c o o l e d exhaust. The e q u i l i brium product d i s t r i b u t i o n s a r e presented as the mole f r a c t i o n of each product formed from t h e t h e o r e t i c a l i n c i n e r a t i o n o f each p e s t i c i d e i n t h e presence o f the s p e c i f i e d moles o f a i r . The major products p r e d i c t e d under these c o n d i t i o n s were r a t h e r simple except f o r those r e s u l t i n g from the presence o f manganese i n maneb and phosphorus i n methyl p a r a t h i o n . The carbon component was o x i d i z e d p r i m a r i l y t o C 0 w i t h s m a l l q u a n t i t i e s o f CO a l s o b e i n g formed. P e s t i c i d e n i t r o g e n was converted mainly t o N and s m a l l amounts o f NO. Most o f the hydrogen formed H 0 o r HCl. S u l f u r was o x i d i z e d p r i m a r i l y t o S 0 and SO3 except f o r maneb. C h l o r i n e was converted mainly t o HCl o r C l . Maneb was t h e o n l y p e s t i c i d e which y i e l d e d s o l i d products a t h i g h temperatures. A t 1727°C t h e manganese was o x i d i z e d t o MnO (Table I V ) . T h i s compound then r e a c t e d w i t h t h e s u l f u r oxides as the gases were c o o l e d t o form MnS04. The phosphorus i n methyl p a r a t h i o n was converted mainly t o P 0 and P4O5 a t 17270C and P 4 0 a t 27°C (Table I V ) . The r e s u l t s o f t h i s study were somewhat s i m p l i f i e d by t h e use o f a thermodynamic model t o p r e d i c t t h e products o f i n c i n e r a t i o n . Three o f t h e systems a f f e c t e d by t h e n e g l e c t o f k i n e t i c s were t h e CO, NO, and SO2-SO3 systems. 2

2

2

3

2

5

2

2

2

2

2

2

2

2

2

2

2

2

1 0

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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2

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I n r e c e n t years the k i n e t i c s o f CO and NO formation and d e s t r u c t i o n have been w i d e l y i n v e s t i g a t e d (21,22). Results o f these i n v e s t i g a t i o n s i n d i c a t e t h a t a c t u a l CO concentrations in automobile exhaust are s i m i l a r t o the e q u i l i b r i u m values a t the combustion temperatures r a t h e r than the e q u i l i b r i u m v a l u e s a t the exhaust temperatures. N i t r i c oxide formation has been found t o occur by two routes. The f i r s t path i s o x i d a t i o n o f atmospheric n i t r o g e n a t temperatures above 1760°C by the f o l l o w i n g reactions. N

2

+ 0.

Ν· + 0 Ν

2

+ NO + N+ NO + O-

+

The other route i s the o x i d a t i o n o f p e s t i c i d e n i t r o g e n . Kinetics of t h i s r e a c t i o n are o f the same order as the combustion process. K i n e t i c s o f CO and NO d e s t r u c t i o n , however, are l i m i t e d d u r i n g expansion. As a r e s u l t , considerable q u a n t i t i e s o f these gases w i l l probably be present i n i n c i n e r a t o r exhaust. Although the c a l c u l a t i o n s i n d i c a t e d t h a t the s u l f u r w i l l be converted t o S 0 and SO3 (Tables IV and V ) , s t u d i e s o f exhaust gases from s u l f u r - c o n t a i n i n g f u e l s have i n d i c a t e d t h a t o n l y 1-3% of the s u l f u r w i l l be o x i d i z e d t o SO3 (23). This f i n d i n g i n d i ­ cates t h a t considerable S 0 w i l l probably be present i n i n c i n e r a ­ t o r exhaust during combustion o f s u l f u r - c o n t a i n i n g p e s t i c i d e s even though none was p r e d i c t e d by the thermodynamic model. Moreover, the SO3 formed w i l l r e a c t w i t h H 0 t o y i e l d H S04 2

2

2

2

(23)· Conclusions Heating o f f u n g i c i d e s and i n s e c t i c i d e s under both optimum and non-optimum c o n d i t i o n s o f combustion produced a number o f p o t e n t i a l a i r p o l l u t a n t s . On a p r a c t i c a l b a s i s a l l o f these gases must be scrubbed from the i n c i n e r a t o r e f f l u e n t p r i o r t o i t s d i s c h a r g e i n t o the atmosphere. Therefore, a scrubber system capable o f absorbing the p o l l u t a n t gases must be developed before i n c i n e r a t i o n can be u t i l i z e d as a method o f d i s p o s a l f o r these p e s t i c i d e s .

Abstract Degradation of six selected fingicides and insecticides was investigated in both open and closed systems. There was evidence that vaporization prior to degradtion could occur in open crucibles. I n i t i a l degradation temperatures determined in sealed ampoules were 275°C for captan, 200°C for maneb and methyl parathion, 525°C for mirex, 175°C for temik, and 250°C

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

0.00

5

1. 16 X i o "

2. 81 X ί ο "

6. 83 X ί ο "

ii

UNO

110.,

6.70 X ί ο "

5.89 X ί ο "

9.50 X ί ο "

4

4

2

1..30 X ! θ "

8..98 X H)"

3.90 X Ι Ο "

0

Oit

9

0.00

5.47 X ί ο "

7.98 X ί ο "

7

7.,57 X ί ο "

1,,71 X ί ο "

ΐ,.,0

N

3

2 8

2 0

1 2

2 8

2

0.00 7.65 X ί ο " 2.84 X ί ο "

4

3

2

1.29 X i o " 1.14 X ί ο " 3.80 X 10~

1.05 X i o -

0.00 5.53 X ί ο " 8.71 X ί ο "

5

3

7

6.A3 X 10~ 1.13 X Ι Ο "

2

1.62 X i o -

2 8

3

7.32 X ί ο " 4.9A X ί ο "

1

2 0

7.25 X 10" 2 1

7.40 X ί ο " 8.85 X ί ο "

7.21 X ί ο " 7

8.91 X ί ο " 9.63 X ί ο " 1

1.60 X i o "

1 2

6.7 A X ί ο " 7 1 1

1

1 7

0.00 3

2.16 X ί ο "

0.00

1 6

1

2.26 X

2.87 X ί ο "

1

9.86 X ί ο "

Ϋ>

1

2

r

1.22 X i o -

3

3.31 X 10"

7.34 X Ι Ο "

0.00 1 0

2 4

1 0

1.09 X ί ο " 1 0

2

2

2 9

2.1A X i o ~

7.65 X i o -

0.00 0.00

3.61 X i o ~

0.00

J 0

1 7

1 0

2.77 X 10"

8

3.16 X ί ο "

1

1.15 x Ι Ο "

2 4

2

2.00 X ί ο "

3.28 X ί ο "

8.51 X ί ο "

0.00

2

1.40 X i o -

2.79 X ί ο "

6

4.53 x 1 0 '

0.00

2..40 X io- '

KO

3

1.. 12 X H ) "

m

3. A3 X l u "

7.63 X ί ο "

0.00

1 0

0.00

0.00

1 0

1, 51 X l u "

~

7. 75 X ί ο "

0

M

1

1.17 X

1 0

1. 77 X i n "

O.,

l!

7.56 X ÎO"

3.34 X 10 -

2

A

2.60 X 10"

4

1.12 X ί ο "

8 4

7

2.16 x ί ο "

0.00

8.79 X ί ο " 0.00

8

1.42 X i o ~ 2.26 κ i o "

0.00

8

0.00

3

1

7

x ίο"

1.42 X ί ο "

2

2

0.00

5

3.48 X i o -

A. 71 X ί ο "

U

1.17 0.00

1

1.15 X Ι Ο "

1

2.61 X 1 ( Γ

0.00

5

27 8.53 X Ι Ο " 0.00

1.25 x ï o -

2 8

3

3

8.45 x ΙΟ""

Tonik

1.18 x Ι Ο "

3

1727

0.00

8.72 x ί ο "

1.71 X i o "

1.13 X ί ο - ;

4

1.66 X ί ο "

2

2 9

2

3

8.52 x ί ο " 8.15 x i o "

27

Mothvl Parathion

2 ίΙ,,β

0.00

3

1727

0. 00

ll

C ( L )

9.51 X ί ο "

8

7

1. 33 X i c f

CO,

2

0.00

2

5

6. 33 x ί ο "

CC

0.00

4

9.30 X ί ο "

3

27

8. 85 x l u "

Maneb

A. 16 X i o "

1727

Ar

Product

Combustion and Exhaust Temperatures ( C)

COMBUSTION PRODUCTS* OF SULFUR-CCNTAINING PESTICIDES IN AIR

TABLE IV

o

1

3

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

0.00

COO

V io

4°i0

P

0.00

0.00

* n.ole fractions L * Iiuuid S « :;eiid.

l

( s )

0.00

Υ\>

0.00

0.00

!

0.00

0.00

i'O

Γ

0.00

0.00

m

0.00

1.67

0.00

0.00

ρ

2

1 0

X

X

ίο""

10~

2

2

5.00

X

3.01 6.00

X

X

1.41 0.00

X

X

X

9.38

1.93

0.00

0.00

0.00

1.68

X

5

10~

io~

ΙΟ"

10~

1.52

2.44

2

1 3

X

1.16

10~

0.00

X

2.85

5

X

3.80 X

io~

3 2

5.06

X

io"

1727

0.00

0.00

X

X

0.00

X

27

9

KnSO, (S)

1.40

X

X

6.33

7.13

X

4.73

3.53

1 0

8

10~

1θ"

io~

1.59

J

?

X

X

1.14

1.59

X

3.98

Maneb

ΠηΟ<$)

so

r>0

SU

t*

° 3j

1727

0.00

0.00 0.00

2

ICf 4

-8 10 ° 2.71

3.92

0.00

6

ίο" icf

0.00

8

ίο"

0.00

0.00

0.00

1.56

5

ίο"

4.37

2

ίο"

0.00 0.00

10

1.84

5

-

10

l
10

ΙΟ"

9

10"

X

X

X

X

X

2

3

10" -8 10

ίο"

14

31

10~

ΙΟ"

27

Methvl Parathion

^

5

0.00

0.00

0.00

0.00 0.00

0.00

0.00

0.00

0.00

0.00

0.00

1.67 χ

8.27 χ

0.00

2

0.00

0.00

3.18 χ

5

10

9

10"

ΙΟ"

ΙΟ"

ίο"

ΙΟ""

9

10"

O.CO

X

X

X

X

X

X

Temik

0.00

0.00

0.00

0.00

0.00

0.00

1.19

1.65

1.92

1.95

7.24

1.06

1727

Combustion and Exhaust Temperatures (°C)

TABLE IV (Cont'd)

27

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1.09 X ί ο "

1.13 X ί ο "

2°2 t!

,!

2

0.00 4.34 X i o ~

2

7

1 0

8

5

1.56 X i o 9.14 X 10~

9

2

5

5

5.60 X ΙΟ" 0.00 1.55 X ΙΟ" 4.36 X ί ο " 8.96 X 10~

H20(L) !U)

II

o

UNO U0 2

HCL

2

ci CI ,0 11

2

1 0

5

2.08 X ί ο "

3

CIO.

1

1.47 X ί ο " 5.58 X 10~ 1.14 X ΙΟ"

0.00

Co., CI CIO

I

0

9

1.40 X ί ο "

3.79 X ί ο "

Co

3

C0C1 CUC1

8. AO X ί ο "

1727

27

2

0.00

2.40 X i o ~

3.34 X ί ο "

3.38 X i o 2

8.90 X ί ο " 0.00

0.00

2 5

3 0

4

2.52 X i o 0.00 0.00 1.02 X ΙΟ" 2

3.15 X ί ο "

1.64 X io" i.34 X io" 1.82 X 10~

8

9

_1

0.00 1.25 X i o ' 3.11 X i o " 0.00

0.00 0.00 0.00 0.00

0.00 0.00

9

2

5

7.82 X IO" 2.76 X IO"

l 0

1 0

7.98 X I O -4 9.92 X 10 7.76 X i o " 8.50 X ~t 1.01 X !0 Λ.58 X io"

5

1 0

-10

4.59 X i o "

2

0.00

0.00

0.00 0.00 0.00

1

21

2 4

1 9

1 9

1

8

1.78 X 1C" 1.14 X i o " 1.56 X io' 2.35 X io#

1

2 6

0.00

30

35

3.40 X i o " 5.33 X IO"

2

2

3 7

0.00 9.21 X i o " 1.25 X IO" 1.55 X i o '

2

4.95 X i o " 1.09 X i o ' 0.00 3.11 X IO"

2

35

2 4

1 9

2.12 X IO"

2.73 X i o " 1.63 X io' 1.19 X i o " i.05 X i o "

0.00 2 9

3

8.32 κ IO" 0.00

3

27 3

1.56 X IO"

8.07 X IO"

1727

Toxaphene

COO

0.00 0.00

0.00 0.00

8

3.25 X ιο" · 1.76 X 1
2.19 X 10 "

_c

1

3 4

1.34 X i o " 1.07 X 10" 4.87 X IO" 0.00

3.24 X i o "

4

20

2 6

1

20

1

3.08 X i o " 1.79 X i o ' 1.76 X i o '

0.00 1.52 X ί ο " 8.40 X ΙΟ" 3.43 X ΙΟ"

1.55 X io" 5.69 X IO"

0.00

0.00

2.36 X 10"""

3

9

8.30 X i o "

27

7.74 X 10-3

1727

Mirex

7

1

3

IN AIR

Combustion and Exhaust Temperatures (°C)

OF CHLORINATED PESTICIDES

0.00

0.00

8.60 X ί ο "

Captan

3

Product

COMBUSTION PRODUCTS

TABLE V

8

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7.12 X i o "

1.6A X i o '

2

3

so

so

3.99 X i o -

1.68 X 10~

·'* mole fractions 1. - liquid.

0.00

0.00

5

5

1 0

0.00

3 4

2 8

2 0

1 3

2

1 3

4

2

1.27 X IO"

1.77 X i o "

so

9.93 X i o "

su

3.09 X i o "

9

1.32 X i o -

6.20 X 10~

1 0

S

A.OA X i o '

2

°2 0..

2.67 X i o "

1.83 X i o ~

0.00

4

7.22 X i o ~

5

9.11 X 10~

1.03 X i o "

7.30 X i o -

7

ΰ

1.11 X 10~

8.25 X i o -

7

0!I

2 KO

2

1

1

N

A.01 X i o "

6

1.A0 X U f

1.12 X i o ~

NO.,

1.A5 X H T

3

1 5

KOC1

1 7

2.31 X i o ~

0.00

0.00

KO

1 0

1.26 κ i o -

27

7.58 X i o "

1 0

Captan

Nil

LZ2Z

Ν

Product

2.13 X 1 (

f

6.02 X 10

-

0.00

0.00

0.00

0.00

0.00

0.00

8.23 X i o "

0.00

8

1

7

3

3

5

6.69 X i o "

6.A9 X i o "

A. 65 X i o "

6

1.A6 X i o "

0.00

1 0

Mirex

7.23 X i o "

Π27

7.50 X l e "

0.00

0.00

0.00

0.00

0.00

0.00

8.A8 X i o -

0,00

0.00

A.AA X i o 2 0

1

1 2

3

6.97 X IO"

8.10 X i o -

1 7

1 4

6.A9 X I O "

0.00

0.00

27

0.00

0.00

0.00

0.00

0.00

1 0

2

4

5

7

1

7

7

3

1,16 X i o "

1.72 X i o "

3.79 X i o "

8.70 X i o '

1.01 X i o "

6.76 X i o "

9.92 X i o "

5.50 X i o "

2.15 X i o '

0.00

1 0

27

0.00

0.00

0.00

0.00

0.00

0.00

1.95 X !0-

0.00

0.00

22

25

22

1 9

3

2.15 κ I O "

6.99 X

1.88 X ! 0 "

2.A7 X i o "

3.11 X I O "

0.00

0.00

Toxaphene

7.39 X H T

1727

Combustion and Exhaust Temperatures (°C)

TABLE V CCont'd)

DISPOSAL AND DECONTAMINATION OF PESTICIDES

98

for toxaphene. Gaseous products produced by heating the pesti­ cides in the temperature range of 400-525°C were identified by mass spectrometry and gas chromatography. Toxic gases identified included HCN, H S, HCl, NO , COS, SO , CS , Cl , CHCl3, CCl , COCl , and C H3Cl. Products resulting from complete combustion were predicted by a series of chemical equilibrum composition calculations. These products included CO , CO, N , NO, H O, HCl, Cl , SO , SO3, MnSO , PO , P O , and Ρ Ο . 2

2

2

2

2

2

2

2

4

2

2

4

2

4

6

4

2

2

10

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

14. 15. 16.

Woodland, R. G., Hall, M. C., Russell, R. R., J. Air Pollu­ tion Cont. Assoc. (1965) 15, 56. Stojanovic, B. J., Kennedy M V. Shuman F L . Jr. J Environ. Quality (1972 Kennedy, M. V., Stojanovic, J., , , , Residue Rev. (1969) 29, 89. Kennedy, M. V., Stojanovic, B. J., Shuman, F. L . , Jr. Agr. Food Chem. (1972a) 20, 341. Kennedy, M. V., Stojanovic, B. J., Shuman, F. L . , Jr., J. Environ. Quality (1972b) 1, 63. Zweig, G., Ed., "Analytical Methods for Pesticides, Plant Growth Regulators, and Food Additives," Vol. III, Academic Press, New York, 1964, pp. 71-74. McDermott, W. H., J. Ass. Off. Anal. Chem. (1973) 56, 1091. Jackson, E. R., Mississippi State Chemical Laboratory, Mississippi State, MS, private communication, 1974. Thompson, J. F., Ed., "Analysis of Pesticide Residues in Human and Environmental Samples," Primate and Pesticide Effects Laboratory, Environmental Protection Agency, Perrine, FL, 1972, Sections 3B and 4A. Sadtler Research Laboratories, Inc., "Sadtler Standard Spectra," Philadelphia, PA, 1968. Thornsberry, W. L . , Jr., Anal. Chem. (1971) 43, 452. Bethea, R. M., Meador, M. C., J. Chromatogr. Sci. (1969) 7, 655. Gordon, S., McBride, B. J., "Computer Program for Calcula­ tion of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and ChapmanJouguet Detonations," NASA SP-237, 1971. Barin, I., Knacke, O., "Thermochemical Properties of Inorganic Substances," Springer-Verlag, Berlin/Heidelburg, 1973. Chase, M. W., Curnutt, J. L., Hu, A. T., Prophet, Η., Syverud, Α. Ν., Walker, L. C., J. Phys. Chem. Data (1974) 3, 311. National Bureau of Standards, JANAF Thermochemical Tables, Second Edition, National Standard Reference Data System National Bureau of Standards 37, 1971.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

7.

KENNEDY ET AL.

Fungicides

and

Insecticides

99

17. Rossini, F. D., Wagman, D. D., Evans, W. H., Levine, S., Jaffe, I., "Selected Values of Chemical Thermodynamic Properties," Circular 500, National Bureau of Standards, February 1, 1952. 18. Eaton, P., Carlson, E., Lombardo, P., Yates, P., J. Org. Chem. (1960) 25, 1225. 19. McBee, E. T., Roberts, C. W., Idol, J. D., Jr., Earle, R. H., J. Amer. Chem. Soc. (1956) 78, 1511. 20. Holloman, M. Ε., Layton, B. R., Kennedy, M. V., Swanson, C. R., accepted for publication in J . Agr. Food Chem., June 12, 1975. 21. Newhall, H. Κ., Twelfth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, PA, 1969, p. 635. 22. Breen, B. P., Bell Rosenthal, Κ., Thirteent Symposiu (International) Combustion, the Combustion Institute, Pittsburgh, PA, 1971, p. 391. 23. Nettleton, Μ. Α., Stirling, R., Twelfth Symposium (Interna­ tional) on Combustion, The Combustion Instutute, Pittsburgh, PA, 1969, p. 635. MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8 Developing Technology for Detoxification of Pesticides and Other Hazardous Materials CHARLES J. ROGERS U.S. Environmental Protection Agency, Cincinnati, O H 45268 ROBERT A L L E N U.S. Environmental Protection Agency, Philadelphia, PA 19106

Promising technologies are continuously being developed to reduce the impact o f toxic and hazardous materials (whether liquid, s e m i - l i q u i d , or solid) on the environment. Although i n the past excess material e a s i e s t , and most economica in the supply o f agricultural chemicals and, more importantly, an increase i n concern for the environment places new emphasis on treatments needed prior to disposal. Specialized techniques investigated by the U.S. Environmental Protection Agency (USEPA) for detoxification o f toxic and hazardous materials include wet oxidation, c h l o r i n o l y s i s , sulfonation, c a t a l y s i s , incineration, micro-wave plasma, encapsulation, and experimental disposal pits that prevent the loss o f unwanted material while allowing biodegradation. The last, a promising technique for treatment o f pesticides used by farmers and agricultural and commercial applicators, i s discussed i n this paper. Pit Disposal o f Excess Hazardous Materials. Ongoing work at Iowa State University includes development o f a simple technique for the disposal o f pesticides l e f t unused i n ground or aerial application operations. At present the safety and effectiveness o f the various disposal systems i n use by a p p l i cators have not been documented to the extent that USEPA can recommend this technique over others. Since 1967, Iowa State University has developed and used a simple p l a s t i c - l i n e d disposal p i t at the Agronomy and A g r i cultural Engineering Research Station near Ames. In 1973, a more sophisticated concrete-lined p i t was constructed at the Horticultural Research Station shown i n Figure 1. There had been no monitoring o f either p i t for effective degradation, possible loss by volatilization, or possible concentration o f hazardous pesticides. To obtain adequate data on the disposal p i t s , a USEPA grant was awarded October 1975 to Iowa State U n i v e r s i t y - - s p e c i f i c a l l y , to evaluate the 0-8412-0433-0/78/47-073-100$05.00/0 This chapter not subject to U.S. copyright. Published 1978 American Chemical Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

ROGERS AND ALLEN

Detoxification

of

Pesticides

101

effectiveness of p i t s currently in use and to determine the factors and parameters for improving the technique. Some of the pesticides used at the Horticulture Station and deposited in the specialized p i t are shown in Table I. TABLE I CHEMICALS USED AT HORTICULTURE STATION Small amounts of leftover diluted materials were deposited. Insecticides Carbaryl 50% (sevin) Chlordane 50% Kelthane 35% Pyrethrum 20% Cythion 25% W.P.

Toxophene E.L (6 lb/gal) Guthio Lannate 90% Heptachlor 30.2% + Xylene 44%

Herbicides Dacthal 2,4-D Paraquat

Ami ben 23% W.P. Tenoran 50% W.P. Casoron Fungicides

Ben!ate Bravo 6F 54% Benlate Captan

Maneb Zineb Sulfur

The chemical and microbiological studies, although incomplete, have revealed that many of the pesticides disposed in the pits can s t i l l be detected. Tables II and III show pesticide concentrations i n ppm for the horticultural farm disposal p i t as sampled i n March and June of 1977. Microbiological studies also have shown that gram negative bacterial species thrive in the pits and a c t i v e l y degrade selected pesticides. To determine the chemical a l t e r a t i o n of pesticides in the horticultural disposal p i t , a mi ni p i t experiment i s being conducted as part of the larger project by personnel from the Departments of Agricultural Engineering, Agronomy, Bacteriology, Botany and Plant Pathology, Energy and Mineral Resource Research I n s t i t u t e , and Entomology at Iowa State University. The slides for the oral presentation (174th meeting of the American Chemical Society, Chicago, August 30, 1977) were taken April 27, 1977, when pretreatment samples were taken and p e s t i cides were added to the mi ni p i t s .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Endosulfan I I

Endosulfan I

Hexachlorobenzene

Ramrod

Dacthal

Bravo

Guthion

Pesticide

2°

2°

2°

2°

Soil

2

H0

Soil

2

H0

Soil

H

Soil

H

Soil

H

Soil

H

Soil

2

H0

Sample Type

0.46 4583 0.30 411 11.5

2.8 309

0.14 3296 0.24 358 13.9

33.0

57.3 5.1

9.9

0.12 63.7

1.5 74

#1

0.15 19.6

*2 #5

0.22 548

3.8 3767

#7

4.0

6.2

0.13 0.50

29.6

65.7

0.29 104 0.15 66.7

0.16 123

57.7

0.25 202

46.2

1.7

3.4

0.12 3.5

4.7

11.2

0.15 74.8

7.8

11.6

0.20 19

2.9 124

#6

13.0

0.26 489

4.0 3064

0.26 0.28 64 1718

0.52 309

8.1 1784

#4

0.21 0.23 0.35 3548 32 2923

0.03 296

2.1 124

*3

PPM AT VARIOUS SAMPLING POINTS

Amount o f Pesticides In PPM at the H o r t i c u l t u r a l Farm Disposal P i t - March 1977

1.7

2.2

0.11 5.9

11.1

0.31 53

0.23 367

2.1 13

#8

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

H

Ramrod

Endosulfan II

Endosulfan I

Hexachlorobenzene

2° Soil

Soil

2

H0

2° Soil

H

2° Soil

H

2° Soil

H

Soil

2

H0

2° Soil

H

sample Type

Dacthal

Bravo

Guthion

Pesticide

11.3

0.20

26.6

0.51

25.0

0.11

6.5

0.07

6.9

.11

0.33 10.4

0.03 1.2

15.3

0.57

50 300

155 57

3.2

0.11

9.2

593

916

6.35 .45 1 3376

.28

0.25

96

29

38

118

0.07 7.0

.14

.64

#4

.20

.09 .19

.14

1.7

1.5 0.02 0.02

0.8

0.03

1.0

3.5 0.14

11.0

0.03

0.25

90

45

5.05

485

1.39

28

0.05

.72

.44

#8

0.11 20.0

151

280

30

92

#7

0.26

9-2

159

36

43

78

#6

0.04 4.2

0.17 27.4

32 163

14

67

191

#5

PPM AT VARIOUS SAMPLING POINTS #3

0.08

29

21

200

20

4

.85

.06

452

118

205

#1

*2

Amount of Pesticides i n PPM at the H o r t i c u l t u r a l Farm Disposal P i t - June 1977

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 1. Concrete-lined disposal pit

Figure 2. An overall view of the minipH area

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

ROGERS AND ALLEN

Figure 3.

Detoxification

of

Pesticides

Closer view of shed and polyvinyl chloride compressed air manifold

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 4. Adding water to a garbage can containing soil (15 kg) to make a total volume of 60 L

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

ROGERS AND ALLEN

Figure 5.

Figure 6.

Detoxification

of

Pesticides

Closeup of water level gage shown in previous slide

Electric motor and propeller stirrer used to mix soil, water, and pesticide(s) in each garbage can

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 7.

Addition of a wettable powder formulation of carbaryl (see Table II) to Minipit 3E

Figure 8.

Continuation of mixing prior to obtaining a sample for analysis

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

ROGERS AND ALLEN

Detoxification

of

Pesticides

Figure 9. Obtaining samples for analysis: a 4-oz jar with a 2-hole rubber stopper (holes in a vertical position) is moved slowly from top to bottom twice in the process of taking a sample

Figure 10. Addition of emulsifiable concentrate formulation of Alachlor to Minipit 5G

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 11.

Obtaining sample for bacteriological analysis immediately after sampling for chemical analysis

Figure 12. Weather station within a few hundred feet of the minipit area. Weather information will be avaifoble for comparison of the analytical data.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

ROGERS AND ALLEN

Detoxification

of

Pesticides

111

The mi ni pit experiment consists of f i f t y - s i x (56) t h i r t y (30) gallon polyethylene garbage cans p a r t i a l l y buried in the ground and arranged i n seven 8-can rows (Figure 2). Four rows contain herbicides (alachlor, atrazine, 2,4-D, and t r i f l u r a l i n ) , with one herbicide per row i n d i f f e r e n t amounts and concentrations. Two rows contain i n s e c t i c i d e s (carbaryl and parathion), one per row, again in d i f f e r e n t amounts and concentrations. The l a s t row contains mixtures of a l l six pesticides. The eight garbage cans per row a l t e r n a t e l y contain 300 gram, 0.5% (w/w) and 15 gram, 0.025% (w/w) pesticide samples. The 0.5% (w/w) concentration represents a reasonable, practical application concentration. The 0.025% (w/w) concentration approximates the d i l u t i o n one might obtain by r i n s i n g the tank on equipment used to apply the pesticide Half of the cans contai The contents of half the cans (some with, some without nutrients) are aerated using a small compressor, a polyvinyl chloride manif o l d , and tygon tubing leading to each f r i t t e d glass aerator. The entire area i s protected by a wire fence and warning signs. Garbage can l i d s are kept i n place between sampling periods. Analyses and evaluations for both the minipits and large p i t will be completed by November 1978. It i s expected that the results will show whether a low-cost, improved p i t disposal system can be developed and recommended for wide-scale use i n the disposal of unwanted pesticides. Summary. The pesticide disposal p i t (macro) located at Iowa State University's horticulture station has been in use for seven years. Water and soil samples were analyzed during the 1976-77 growing season for chemical, biological and microbial a c t i v i t y and content. The major finding, as substantiated by chemical and microbiological data, i s that no build-up of pesticide residues in the p i t occurs. Sampling and analyzing of the p i t at various locations revealed that inhomogeneity of pesticide d i s t r i b u t i o n existed. Consequently, minipit experiments were designed to determine trends i n pesticide degradation, and the overall fate of pesticides disposed of in the p i t s . It i s expected that at the conclusion of 1978, s u f f i c i e n t data w i l l be available for f u l l - s c a l e demonstration of t h i s disposal technique. MARCH 23,

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

9 Pyrolysis and Disposal of Mirex Residues BOBBY R. LAYTON and E A R L G. A L L E Y Mississippi State Chemical Laboratory, Box CR, Mississippi State, MS 39762

At the request o f the Mississippi Imported Fire Ant A u t h o r i t y , methods were i n v e s t i g a t e d f o r the d i s p o s a l o f shipment drums contaminated w i t h mirex , pentacyclo [5.3.0.02,6.03,9.04,8] s t u d i e s on mirex ( 1, 2, 3) showed t h a t this compound i s t h e r m a l l y s t a b l e and r e s i s t a n t t o most common oxidizing and r e d u c i n g systems. However, mirex has been shown t o d e c h l o r i n a t e photoc h e m i c a l l y (4, 5, 6). Mirex has a l s o been found to undergo red u c t i v e d e c h l o r i n a t i o n in the presence o f reduced hematin (7) and when incubated under anaerobic c o n d i t i o n s w i t h sewage sludge. McBee e t al. (1) and Eaton e t al. (2) have i n d i c a t e d mirex py­ rolysis occurs o n l y a t temperatures above 500°. Holloman e t al. (10) found t h a t a t 7 0 0 ° the major p y r o l y s i s product o f mirex was hexachlorobenzene. I t was the o b j e c t o f this reseach to determine whether mirex r e s i d u e s in shipment c o n t a i n e r s c o u l d be reduced t o acceptable levels by combinations o f chemical e x t r a c t i o n , chemical degradation, o r pyrolysis.

0-8412-0433-0/78/47-073-112$05.00/0 © 1978 American C h e m i c a l Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

9.

Mirex

LAYTON AND ALLEY

Residues

112

P y r o l y s i s of M i r e x and I t s D e r i v a t i v e s The photochemical (4^ 5) and r e d u c t i v e d e c h l o r i n a t i o n (7) s t u d i e s i n d i c a t e d the major products of mirex degradation are 1,2,3,4,5,5,6,7,8,9,10 undecachloropentacyclo [5.3.0.0 » .0 » .0 > ] decane ( I I ) ; 1,2,3,4,5,5,6,7,9,10,10 undecachloropentacyclo [5.3.0.0 > .0 > .0 > ] decane ( I I I ) ; 1,2,3,4,5,6,7,8,9,10 decac h l o r o p e n t a c y c l o [5.3.0.0 > .0 » .0*> ] decane ( I V ) ; and 1,3,4,5, 5,6,7,9,10,10 decachloropentacyclo [5.3.0.0 > .0 > .0 > ] decane (V). The p y r o l y s i s of these compounds and mirex were s t u d i e d a t v a r i o u s temperatures and the r e s u l t s of these experiments are given i n Tables 1, 2, 3, 4, and 5. A f t e r mirex was placed i n g l a s s ampules, the ampules were evacuated t o 0.5 mm Hg pressure and s e a l e d . These seale As shown i n Table 1, th both hexachlorobenzene and hexachlorocyclopentadiene. At 600° the mirex gave h i g h y i e l d s of hexachlorobenzene. When heated t o 493°, the monohydrogen d e r i v a t i v e s of mirex, compounds I I and I I I , produced some hexachlorobenzene and hexachlorocyclopentadiene but a l s o y i e l d e d some carbonaceous m a t e r i a l (Tables 2 and 3 ) . The 5,10-dihydrogen d e r i v a t i v e , compound IV, y i e l d e d even more carbonaceous m a t e r i a l when heated t o 493° (Table 5) than the monohydrogen d e r i v a t i v e s . At 493° the 2,8-dihydrogen d e r i v a t i v e of mirex produced predominately carbonaceous m a t e r i a l and no m a t e r i a l s which were s o l u b l e i n carbon d i s u l f i d e . Since mirex and t h r e e of i t s d e r i v a t i v e s a l l produced hexachlorobenzene, v e r y l i t t l e i n f o r m a t i o n was obtained about the mechanism of the p y r o l y s i s r e a c t i o n . However, i t was observed t h a t p y r o l y s i s of mirex y i e l d e d hexachlorocyclopentadiene b e f o r e the hexachlorobenzene was formed. To t e s t t h i s h y p o t h e s i s f u r t h e r , hexachlorocyclopentadiene was heated a t temperatures ranging from 493° t o 550° (Table 6 ) . At the h i g h e s t temperature (550°) and at l o n g e r r e a c t i o n times the hexachlorobenzene was formed. 2

4

6

3

8

2

6

3

9

4

8

2

6

3

9

8

2

6

3

9

4

8

Table 1 P y r o l y s i s of Mirex Temp. C°

Ratio

Products

Time Min.

493

30

Mirex Mirex, C C1 , c ci c ci , c ci

600

30

C C1 , C C1

475 490

15 15

6

5

6

6

6

10:10:1

Remarks

No Carbon No Carbon

6

6

6

5

5

6

1:0.65

6

1:0.06

No Mirex No Carbon No Carbon

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

9

DISPOSAL AND DECONTAMINATION OF PESTICIDES

114

Table 2 P y r o l y s i s 10-Hydrogen Mirex Ratio

Time Min.

Products

400 481 493

15 2 5

493

30

10-H, C C 1 c ci C C1 , c c i (trace) C C1 , C C1

Temp. C°

5

6

5

6

5

6

6

6

5

6

6

6

Remarks

5:1

L i g h t Carbon L i g h t Carbon Medium Carbon

1:6

Heavy Carbon

P y r o l y s i s of 8-Hydrogen Mirex Temp. C° 400 490 493

Time Min.

Ratio

Products

Low Y i e l d Low Y i e l d Good Y i e l d

8-H 8-H

60 60 30

C

6

C 1

6

Remarks

Heavy Carbon Heavy Carbon L i g h t Carbon

Table 4 P y r o l y s i s of 5,10-Dihydrogen Mirex Temp. C° 400 420 493 493

Time Min.

Products

Ratio

60 60 30 60

5,10 d i H 5,10 d i H c ci , c ci c ci

Low Y i e l d Low Y i e l d 1:16

5

6

6

6

6

6

Remarks

Heavy Heavy Heavy Heavy

Carbon Carbon Carbon Carbon

Table 5 P y r o l y s i s o f 2,8-Dihydrogen Mirex Temp. C°

Time Min.

Products

465

2

Carbon

493

30

Carbon

Ratio

Remarks

No s o l u b l e products No s o l u b l e products

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

9.

LAYTON AND

ALLEY

Mirex

115

Residues

Table 6 P y r o l y s i s of Hexachlorocyclopentadiene Temp. C° 493 500 500 520 550 550

Time Min.

Products

10 5 5 5 5 5

C-Ci>, c c i 6

C5C16 c ci c ci , C6C16 5

6

5

6

c ci 6

Ratio

6

1:1

1:5 6

Remarks

Oxygen Nitrogen Nitrogen Nitrogen Oxygen

Chemical E x t r a c t i o n Another study was designed to determine whether s o l v e n t e x t r a c t i o n techniques c o u l d be devised to lower the mirex r e s i dues i n the drums to an acceptable l e v e l . Hexane was chosen t o e x t r a c t the p l a s t i c l i n e r s because many other s o l v e n t s such as methylene c h l o r i d e and t e t r a h y d r o f u r a n a t t a c k the p l a s t i c . A simple r i n s i n g of the b a r r e l and the p l a s t i c l i n e r s (1 ml/60 cm ) w i t h hexane removed l e s s than 15% of the mirex r e s i d u e (Table 7 ) . The percent decontamination was based on the t o t a l amount of mirex which would be e x t r a c t e d i n 24 hours i n a Soxhlet e x t r a c t o r u s i n g hexane as the s o l v e n t . A r a p i d immersion of the drum i n methylene c h l o r i d e and the l i n e r s i n hexane (Table 8) removed much more mirex (81-99%), but the r e s u l t s v a r i e d too much t o be acceptable. A s i n g l e f i v e minute immersion of the l i n e r s (Table 9) i n hexane removed 95-98% of the mirex. A second Immersion brought the t o t a l decontamination t o 99 t o 99.9% f o r the l i n e r s . T h i s technique was not s a t i s f a c t o r y f o r decontaminating the f i b e r drums s i n c e f o u r immersions were necessary to remove 81% of the mirex. A comparison of Tables 8 and 9 i n d i c a t e s t h a t methylene c h l o r i d e i s much more e f f i c i e n t f o r e x t r a c t i n g the f i b e r drums than i s hexane. 2

Conclusion Chemical degradation and a combination of chemical degradat i o n and i n c i n e r a t i o n i n a standard i n c i n e r a t o r were found t o be u n s a t i s f a c t o r y methods f o r decontaminating the shipment c a r t o n s . E x t r a c t i o n of the mirex from the drums and l i n e r s were deemed p o s s i b l e but expensive. A l t e r n a t i v e s o l u t i o n s t o the problem are (a) burn the drums and l i n e r s i n an i n c i n e r a t o r capable of decontaminating mirex (b) r e t u r n cartons t o the manufacturer f o r r e use.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

116

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Table 7 Removal of Mirex from Shipping Containers Hexane Rinse Rinse (lml/60cm ) 2

Barrel ppm (% removal)

Inner Bag ppm (% removal)

Middle Bag ppm (% removal)

Outside Bag ppm (% removal)

1.24(0.4) 0.25(0.5) 0.05(0.5) 0(0.5

3,650(11) 370(12) 129(13)

175(4.7) 26(5.4) 11(5.7)

172(4.7) 24(6.4) 15(6.8) 11(6.1

Soxhlet E x t r a c t o r Barrel 300 ppm

(Hexane)

Inner Bag 32,000 ppm

Middle Bag 3,700 ppm

Outside Bag 3,600 ppm

C u m u l a t i v e percent based on Soxhlet E x t r a c t i o n

Table 8 Removal of M i r e x from Shipping Containers by Immersion i n a Solvent Wash Barrel (1.5ml/cm ) (methylene chloride) 4

1 2

300 ppm

Inner Bag (hexane)

Middle Bag (hexane)

Outside Bag (hexane)

21,000 ppm 2,500 ppm

4,000 ppm 520 ppm

3,700 ppm 700 ppm

Table 9 Removal o f Mirex from Shipping Containers by Soaking i n Hexane f o r 5 Minutes Soak (lml/cm ) 2

1 2 3

4 Extraction (4 h r s . )

Barrel ppm (%)

Inner Bag ppm (%)

400(47) 100(58) 60(64) 150(81) 163

35,000(98) 670(99.9) 30(99.9) 13(99.9) 0.5

Middle Bag ppm (%) 2,300(97) 50(99) 17(99.9) 1(99.7)

5.4

Outside Bag ppm (%) 3,300(95) 170(99.8) 4.3(99.9) 0.4(99.9) 0.9

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

9.

LAYTON AND ALLEY

Mirex

Residues

117

Literature Cited 1. McBee, E. T., Roberts, C. W., Idol, J. D., Jr., Earle, R. H., Jr., J. Amer. Chem. (1956), Soc. 78, 1511. 2. Eaton, P., Carlson, Ε., Lombardo, P., Yates, P., J. Org. Chem. (1960), 25, 1225. 3. Dilling, W. L., Braendlin, H. P., McBee, E. T., Tetrahedron (1967), 23, 1211. 4. Alley, E. G., Dollar, D. Α., Layton, B. R., Minyard, J. P., Jr., J. Agric. Food Chem. (1973), 21, 138. 5. Alley, E. G., Layton, B. R., Minyard, J. P., Jr., J. Agric. Food Chem. (1974), 22, 727. 6. Gibson, J. R., Ivie, G. W., Dorough, H. W., J. Agric. Food Chem. (1972), 20, 1246 7. Holmstead, R., J. 8. Andrade, P. S. L . , Jr., Wheeler, W. B., Bull. Environ. Contam. Toxicol. (1974), 11, 415. 9. Ivie, G. W., Dorough, H. W., Alley, E. G., J. Agric. Food Chem. (1974), 22, 933. 10. Holloman, Μ. Ε., Layton, B. R., Kennedy, M. V., Swanson, C. R., J. Agric. Food Chem. (1975), 23, 1011. MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

10 Destruction of Pesticides and Pesticide Containers by Molten Salt Combustion S. J. YOSIM, Κ. M. BARCLAY, and L. F. GRANTHAM Rockwell International, Atomics International Division, 8900 DeSoto Avenue, Canoga Park, CA 91304

The disposal of hazardous wastes such as pesticides is re­ ceiving increasing attention. Alternate methods to the tradi­ tional means of disposa rivers, lakes, and oceans incineration) are being sought. This paper presents some experimental results which dem­ onstrate the feasibility of applying molten salt combustion tech­ nology to the disposal of pesticides and their containers. The concept of molten salt combustion is described first. This is followed by a description of the molten salt combustors used at Atomics International. Then some results of molten salt com­ bustion tests on pesticides and pesticide container material are given. A brief description of a portable unit for this application concludes the paper. Concept of Molten Salt Combustion In the Atomics International concept for molten salt combus­ tion, shown in Figure 1, combustible material and air are con­ tinuously introduced beneath the surface of a molten salt. The combustible material is added in such a manner that any gas formed during combustion is forced to pass through the melt before it is emitted into the atmosphere. The off-gas contains carbon dioxide, steam, nitrogen, and unreacted oxygen. This gas is cleaned of particulates by scrubbing in a venturi scrubber or by passing it through a baghouse. The heating value of the waste is, in general, sufficient to generate enough heat to heat the reactants to the required temperature, maintain the salt in the molten state, and balance all heat losses from the system. Ash and other noncombustible materials build up in the melt and must be removed. In certain applications with low through­ put, the salt-ash mixture is removed batchwise and discarded. When the throughput is sufficiently large, a side stream of the melt is withdrawn either batchwise or continuously and is proc­ essed. The ash must be removed to preserve the fluidity of the 0-8412-0433-0/78/47-073-118$05.00/0 © 1978 American Chemical Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

10.

Destruction

YOSIM ET AL.

of

119

Pesticides

STACK

1 OFF-GAS CLEANUP

Τ WASTE SALT RECYCLE 1f WASTE TREATMENT AND FEED MOLTEN SALT FURNACE

I SPENT MELT ^PREPROCESSING! *[ OPTION !

AIR WASTE AND AIR

SPENT MELT DISPOSAL

τ

ASH 40417-4037

Figure 1. Molten salt combustion process concept

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

120

DISPOSAL AND DECONTAMINATION OF PESTICIDES

m e l t at a n a s h c o n c e n t r a t i o n of about 20 wt %. T h e spent m e l t is f i r s t quenched in water. T h e s o l u t i o n i s then f i l t e r e d to r e m o v e the a s h a n d p r o c e s s e d to c o n v e r t s o l u b l e i m p u r i t i e s to disposable products. T h e r e g e n e r a t e d s a l t i s then r e c y c l e d to the c o m b u s t o r . A h y d r a u l i c aqueous s i m u l a t i o n of the a i r - s p a r g e d m o l t e n s a l t c o m b u s t o r i s shown i n F i g u r e 2. In this s i m u l a t o r , c o n c e n t r a t e d aqueous z i n c c h l o r i d e i s u s e d . The intimate contact of the a i r a n d l i q u i d c a n be s e e n . T h i s i n t i m a t e c o n t a c t i n the c a s e of a m o l t e n s a l t p l u s the i n t i m a t e c o n t a c t o f both f l u i d s w i t h c o m b u s t i b l e m a t e r i a l p r o v i d e f o r c o m p l e t e a n d r a p i d d e s t r u c t i o n of such material. M o l t e n s o d i u m c a r b o n a t e c o n t a i n i n g 10 wt % s o d i u m sulfate i s the s a l t u s e d f o r c o m b u s t i o n Sodium carbonate is used be c a u s e i t i s a l k a l i n e an H C l (produced f r o m organi SO2 organic sulfur compounds). T h e s o d i u m sulfate c a t a l y z e s the c o m b u s t i o n r a t e of c a r b o n . T h i s s a l t s y s t e m w h i c h o p e r a t e s at 800 to 1 0 0 0 ° C i s s t a b l e , n o n v o l a t i l e , i n e x p e n s i v e , a n d n o n t o x i c . T h e c h e m i c a l r e a c t i o n s of the w a s t e w i t h s a l t a n d a i r d e p e n d on its constituents. T h e c a r b o n a n d h y d r o g e n of the w a s t e a r e c o n v e r t e d to CO2 a n d s t e a m , r e s p e c t i v e l y . T h e h a l o g e n s f o r m the corresponding sodium halide salts. The phosphorus, sulfur, a r s e n i c , a n d s i l i c o n ( f r o m g l a s s o r a s h i n the waste) f o r m the o x y g e n a t e d s a l t s , NagPO4, N a ^ S O ^ N a A s O g , a n d N a 2 S i U 3 , r e spectively. The i r o n f r o m m e t a l containers f o r m s i r o n oxide. T h e t e m p e r a t u r e s of c o m b u s t i o n a r e too l o w to p e r m i t a s i g n i f i c a n t a m o u n t of n i t r o g e n o x i d e s to be f o r m e d b y f i x a t i o n of the n i t r o g e n i n the a i r . T h e a s h i s t r a p p e d i n the m e l t . A t the o p e r ating t e m p e r a t u r e s above 8 0 0 ° C , o d o r and i n f e c t i o u s m a t e r i a l are completely destroyed. Molten Salt Combustion Facilities T h e r e a r e two m o l t e n s a l t c o m b u s t i o n f a c i l i t i e s at A t o m i c s International. One i s a b e n c h - s c a l e m o l t e n s a l t c o m b u s t o r f o r d i s p o s i n g of 1 /2 to 2 I b / h of w a s t e . F e a s i b i l i t y and o p t i m i z i n g t e s t s a r e g e n e r a l l y c a r r i e d out i n this c o m b u s t o r . The other i s a p i l o t p l a n t c o m b u s t o r , c a p a b l e of d i s p o s i n g of 50 to 200 l b / h of w a s t e , a n d i s u s e d to o b t a i n e n g i n e e r i n g data f o r r e l i a b l e e x t r a p o l a t i o n to a f u l l - s c a l e plant. B e n c h - S c a l e M o l t e n S a l t C o m b u s t o r . A s c h e m a t i c of the b e n c h s c a l e m o l t e n s a l t c o m b u s t o r i s shown i n F i g u r e 3. A p p r o x i m a t e l y 12 l b of m o l t e n s a l t a r e c o n t a i n e d i n a 6 - i n . ID a n d 3 0 - i n . h i g h a l u m i n a tube p l a c e d i n a T y p e 321 s t a i n l e s s s t e e l r e t a i n e r v e s s e l . T h i s s t a i n l e s s s t e e l v e s s e l , i n t u r n , i s c o n t a i n e d i n an 8 - i n . I D , f o u r h e a t i n g zone M a r s h a l l f u r n a c e . T h e four heating zones a r e e a c h 8 i n . i n h e i g h t , a n d the t e m p e r a t u r e of e a c h zone i s c o n t r o l l e d b y an S C R c o n t r o l l e r . F u r n a c e and r e a c t o r temperatures a r e r e c o r d e d by a 12-point B a r b e r - C o l m a n c h a r t r e c o r d e r .

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

YOsiM ET AL.

Destruction of Pesticides

Figure 2.

Hydraulic simulation of air-sparged molten salt

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

AIR IN

0 TO 400 rpm SCREW FEEDER

1/2 in. STAINLESS STEEL INJECTOR TUBE

SEPTUM FOR GAS SAMPLE AND PARTICULATE SAMPLING PROBE ATTACHED HERE) STAINLESS STEEL RETAINER VESSEL 1-1/2 in. ID ALUMINA FEED TUBE MARSHALL FURNACE 6 in. ID ALUMINA TUBE

6 in. DEPTH OF MOLTEN SALT

42400-1016A Figure 3.

Bench-scale molten salt combustor

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

10.

YOSiM ET AL.

Destruction

of

123

Pesticides

S o l i d s , p u l v e r i z e d i n a N o . 4 W i l e y m i l l to <1 m m i n p a r t i c l e s i z e , a r e m e t e r e d into the 1 / 2 - i n . O D c e n t r a l tube of the i n j e c tor b y a s c r e w f e e d e r . R o t a t i o n o f the s c r e w f e e d e r i s p r o v i d e d b y a 0 to 4 0 0 - r p m E b e r b a c k C o r p o r a t i o n C o n - T o r q u e s t i r r e r m o t o r . In the i n j e c t o r , the s o l i d s a r e m i x e d w i t h the a i r b e i n g u s e d f o r g a s i f i c a t i o n , a n d this s o l i d s - a i r m i x t u r e p a s s e s d o w n w a r d t h r o u g h the c e n t e r tube of the i n j e c t o r a n d e m e r g e s into the 1 - 1 / 2 - i n . I D a l u m i n a f e e d tube. T h i s a l u m i n a f e e d tube i s a d j u s t e d so that its end i s 1/2 i n . above the b o t t o m of the 6 - i n . d i a m e t e r a l u m i n a r e a c t o r tube. T h u s , the s o l i d s - a i r m i x t u r e i s f o r c e d to p a s s d o w n w a r d t h r o u g h the feed tube, o u t w a r d at i t s b o t t o m e n d , a n d then u p w a r d t h r o u g h 6 i n . o f s a l t i n the a n n u l u s b e t w e e n the 1 - 1 / 2 - i n . a n d the 6 - i n . a l u m i n a tubes. In the c a s e of l i q u i d s , a d i f f e r e n t f e e d i used Th liquid i d with a l a b o r a t o r y pum P i l o t - S c a l e M o l t e n S a l t C o m b u s t o r . P h o t o g r a p h s of the m o l t e n s a l t p i l o t c o m b u s t o r and s o m e of the a u x i l i a r y c o m p o nents a r e shown i n F i g u r e s 4 a n d 5, r e s p e c t i v e l y . T h e m o l t e n s a l t v e s s e l , 10 ft h i g h and 3 ft I D , i s m a d e of T y p e 304 s t a i n l e s s s t e e l , a n d i s l i n e d w i t h 6 - i n . - t h i c k r e f r a c t o r y b l o c k s . It c o n t a i n s 1 ton of s a l t , w h i c h c o r r e s p o n d s to a depth of 3 ft, w i t h no a i r flow t h r o u g h the b e d . T h e v e s s e l i s p r e h e a t e d o n s t a r t u p a n d kept h o t o n s t a n d b y b y a n a t u r a l - g a s - f i r e d burner. T h e s a l t l o a d i n g i s f e d into the m o l t e n s a l t v e s s e l t h r o u g h the c a r b o n a t e f e e d e r . T h e c o m b u s t i b l e m a t e r i a l s to be p r o c e s s e d a r e t r a n s f e r r e d d i r e c t l y f r o m the h a m m e r m i l l , i n w h i c h they a r e c r u s h e d to the r e q u i r e d s i z e , into a f e e d h o p p e r p r o v i d e d w i t h a v a r i a b l e - s p e e d a u g e r , a n d then i n t r o d u c e d into the a i r s t r e a m f o r t r a n s p o r t into the v e s s e l . T h e e x h a u s t g a s e s g e n e r a t e d i n the v e s s e l e x i t t h r o u g h r e f r a c t o r y - l i n e d tubes i n the v e s s e l h e a d to a r e f r a c t o r y - l i n e d m i s t separator. T h e s e p a r a t o r t r a p s e n t r a i n e d m e l t d r o p l e t s on a baffle a s s e m b l y . T h e g a s e s a r e then d u c t e d to a h i g h - e n e r g y v e n t u r i s c r u b b e r o r to a b a g h o u s e , w h i c h i s u s e d to r e m o v e a n y p a r t i c u l a t e m a t t e r b e f o r e r e l e a s e to the a t m o s p h e r e . A n overf l o w w e i r p e r m i t s c o n t i n u o u s r e m o v a l o f spent s a l t , thus p e r m i t t i n g l o n g - t e r m t e s t s to be c a r r i e d out. R e s u l t s of C o m b u s t i o n T e s t s T h e c o n t a i n e r m a t e r i a l s t e s t e d i n c l u d e d those that w e r e c o m b u s t i b l e ( p a p e r , p l a s t i c , a n d r u b b e r ) as w e l l as n o n c o m b u s t i b l e (glass a n d m e t a l ) . The pesticides which were tested i n c l u d e d D D T , m a l a t h i o n , c h l o r d a n e , and 2,4D. C o n t a i n e r M a t e r i a l s . A s u m m a r y c h a r t g i v i n g the r e s u l t s of c o m b u s t i o n t e s t s i n the b e n c h - s c a l e u n i t w i t h p a p e r , p l a s t i c , r u b b e r , a n d a b l e n d of these w a s t e s i s shown i n T a b l e I. Combustion was complete i n a l l c a s e s . T h e C O (*0.2%), N O x

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

124

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 4. Pilot-scale molten salt combustor

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978. 8.3 11.9

8.3 10.7

0.05 0.1

0.05 0.05

980 960

982 960

5

5

5

5

1.6

1.1

0.7

1.5

Plastic (50% P V C 50% P E )

Rubber

Blend (60% P a p e r , 30% P l a s t i c , 10% R u b b e r )

0.35 0.14

<25 <25

62 27

emission.

0.24 <25

18

0.03

Particulates^ (grains/scf)

<25

Hydr oca rbon s as Ν - H e x a n e (ppm)

13

ΝΟχ (ppm)

Effluent A n a l y s i s

* T h e gas s u p e r f i c i a l v e l o c i t y was 2 f t / s . t T h e b e n c h - s c a l e u n i t was not d e s i g n e d to m a i n t a i n l o w p a r t i c u l a t e

(%)

(%)

CC)

2

co

CO

Paper

Waste Material

Tempera­ ture

Air Feed Rate" (scfm)

Feed Rate (lb/h)

SUMMARY CHART - M O L T E N S A L T COMBUSTION O F COMBUSTIBLE CONTAINER MATERIALS

TABLE I

DISPOSAL AND DECONTAMINATION OF PESTICIDES

126

(<65 p p m ) , a n d u n b u r n e d h y d r o c a r b o n s (<30 ppm) c o n c e n t r a t i o n s i n the o f f - g a s w e r e v e r y l o w . N o H C l was d e t e c t e d i n the t e s t s with P V C . T h e p a r t i c u l a t e l o a d i n g i n the o f f - g a s w a s r a t h e r l o w c o n s i d e r i n g that no p a r t i c u l a t e r e m o v a l d e v i c e w a s p r e s e n t i n the b e n c h - s c a l e c o m b u s t o r . C o m b u s t i o n t e s t s on 1500 l b of s i m u l a t e d p e s t i c i d e c o n t a i n ­ e r s w e r e p e r f o r m e d i n the p i l o t c o m b u s t o r at f e e d r a t e s of 70 lb/h. The waste contained p a p e r , polyethylene, P V C , and rubber. T h e r e s u l t s a r e shown i n T a b l e II. N o H C l (<5 p p m ) , S0 (<2 p p m ) , C O (<0.1%), o r h y d r o c a r b o n s (<0.1%) w e r e d e ­ tected. T h e N O c o n c e n t r a t i o n was about 30 p p m . 2

x

TABLE Π O F F - G A S ANALYSI SIMULATED PESTICIDE CONTAINERS IN P I L O T P L A N T 1500 l b o f W a s t e B u r n e d at 7 0 - l b / h R a t e Waste Contained P a p e r , Polyethylene,

P V C and Rubber

Off-Gas Analysis: HCl

ND*

so

ND

(<2 ppm)

CO

ND

(<0.1%

HC

ND

(<0.1%)

2

30 p p m

NO

X °2

co N

2

(<5 ppm)

2

5-12% 10-15%

76-78%

* N D - Not Detected T h e r e a c t i o n r a t e of g l a s s w i t h m e l t was m o d e r a t e at 9 0 0 ° C ( c o m p l e t e i n about 30 m i n ) a n d was r a p i d at 1 0 0 0 ° C . At 1000°C, the g l a s s r e a c t e d as r a p i d l y as i t w a s a d d e d . The reaction rate, i n the c a s e of m e t a l , was c o n s i d e r a b l y s l o w e r . Surface c o r r o ­ s i o n of about 70 m i l s took p l a c e i n 8 h at 9 0 0 ° C . W h i l e the r e ­ a c t i o n r a t e i s e x p e c t e d to be s i g n i f i c a n t l y h i g h e r at 1 0 0 0 ° C , i t i s n o t r e c o m m e n d e d that m o l t e n s a l t s be u s e d to c o m p l e t e l y d i s i n ­ tegrate m e t a l containers. A n o t h e r o p t i o n i s to i m m e r s e the c o n ­ t a i n e r s f o r s e v e r a l m i n u t e s i n the m e l t f o r a d e c o n t a m i n a t i o n r i n s e only.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

10.

YOSIM ET AL.

Destruction of Pesticides

127

Pesticides. T y p i c a l c o m b u s t i o n results with D D T and m a l a t h i o n p e r f o r m e d i n the b e n c h - s c a l e u n i t a r e shown i n T a b l e III. The m e l t s contained either o r K2CO3. T h e u s e of K2CO3 i s of i n t e r e s t b e c a u s e the c o m b u s t i o n p r o d u c t , KC1, c a n be u s e d as a f e r t i l i z e r . D e s t r u c t i o n of the p e s t i c i d e was g r e a t e r than 99.99%. N o p e s t i c i d e s w e r e d e t e c t e d i n the m e l t ; h o w e v e r , t r a c e s of p e s t i c i d e s w e r e d e t e c t e d i n the o f f - g a s . T h e l a s t two c o l u m n s of T a b l e H I c o m p a r e the c o n c e n t r a t i o n of p e s t i c i d e i n the o f f - g a s w i t h t h r e s h o l d l i m i t v a l u e s ( T L V ) . (The T L V ' s r e f e r to a i r b o r n e c o n c e n t r a t i o n s of s u b s t a n c e s a n d r e p r e s e n t c o n d i tions u n d e r w h i c h i t i s b e l i e v e d that n e a r l y a l l w o r k e r s m a y be r e p e a t e d l y e x p o s e d , d a y a f t e r d a y , without a d v e r s e effect.) T h e c o n c e n t r a t i o n s of p e s t i c i d e s i n the o f f - g a s w e r e g e n e r a l l y w e l l b e l o w the T L V . This the o f f - g a s w i l l be c o n s i d e r a b l w o r k e r a r e a . A n o t h e r c o n s i d e r a t i o n i s the f a c t that i n these t e s t s , a 6 - i n . - d e e p s a l t b e d was u s e d . In an a c t u a l d i s p o s a l p l a n t , a 3 6 - i n . - d e e p s a l t b e d i s e x p e c t e d to be u s e d . This will i n c r e a s e the r e s i d e n c e t i m e a n d c o n t a c t t i m e b y a f a c t o r o f 6; t h e r e f o r e , the e x t e n t of d e s t r u c t i o n of these p e s t i c i d e s i s e x p e c t e d to e x c e e d c o n s i d e r a b l y the 99.99%+ found i n the l a b o r a t o r y tests. T h e h e r b i c i d e 2 , 4 D (an e s t e r of d i c h l o r o p h e n o x y a c e t i c a c i d ) was of i n t e r e s t b e c a u s e i t was a n a c t u a l w a s t e w h i c h c o n t a i n e d 30 to 50% 2 , 4 D , a n d 50 to 70% t a r s ( m o s t l y b i s - e s t e r a n d d i chlorophenol tars). The waste, w h i c h was r a t h e r v i s c o u s , was d i l u t e d b y the a d d i t i o n of 1/4 i t s w e i g h t w i t h e t h a n o l . The des t r u c t i o n o f the h e r b i c i d e at 8 3 0 ° C w a s >99.98%; no o r g a n i c c h l o r i d e s o r H C l w e r e d e t e c t e d i n the m e l t o r i n the e x h a u s t g a s . (In this c a s e , a l e s s s e n s i t i v e a n a l y t i c a l technique was u s e d . ) E a r l i e r tests w e r e p e r f o r m e d w i t h c h l o r d a n e . N o c h l o r d a n e w a s d e t e c t e d i n the o f f - g a s . G r e a t e r than 99.96% of the p e s t i cide was destroyed. T h e e f f e c t i v e n e s s of s o d i u m c a r b o n a t e i n p r e v e n t i n g H C l e m i s s i o n s was d e t e r m i n e d . In this t e s t , t r i c h l o r o e t h a n e (C2H3CI3), w h i c h c o n t a i n s 80 wt % C I , w a s c o m b u s t e d to d e t e r m i n e h o w m u c h of the N a 2 C U 3 c o u l d be c o n v e r t e d into N a C l a n d s t i l l be p r e s e n t i n s u f f i c i e n t a m o u n t to p r e v e n t H C l e m i s s i o n s . P r e v e n t i o n of H C l e m i s s i o n s w a s a c c o m p l i s h e d w i t h as l i t t l e as 2 wt % N a o C O j . N o t r i c h l o r o e thane (<0.001% of the m a t e r i a l fed) c o u l d be d e t e c t e d i n the o f f - g a s . C o n c e p t u a l S t u d y of a P o r t a b l e M o l t e n S a l t D i s p o s a l S y s t e m A conceptual and p r e l i m i n a r y design for a portable m o l t e n s a l t u n i t f o r d i s p o s a l of e m p t i e d p e s t i c i d e c o n t a i n e r s w a s c o m pleted. A n a r t i s t ' s c o n c e p t i s shown i n F i g u r e 6, w h i c h shows a c o m b u s t o r and the a u x i l i a r y c o m p o n e n t s m o u n t e d on a t r u c k b e d . T h e c o m b u s t o r , w h i c h i s a 6 - f t I D a n d 11 ft t a l l , i s c a p a b l e of

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 5. Feed system for the molten salt test facility

Figure 6.

Portable molten salt waste disposal system

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

3

* Threshold L i m i t Value t N o t Detected

2

3

15 N D <0.4

<0.005

ND

99.999

896

K CO

Malathion

2

15

<0.01

ND

99.996

922

Na C0

Malathion

1.1

I 0.3

<0.2

ND

99.998

894

3

K CO

DDT

2

1

1.4

N D Ï <0.05

99.997

3

922

2

Na C0

DDT

3

3

T L V * of Pesticide (mg/m )

Salt

Pesticide

Quantity in Exhaust Gas (mg/m )

Concentra­ t i o n of Pesticide in Melt (ppm)

Percent Pesticide Destroyed

Average Test Temper­ ature (°C)

TYPICAL RESULTS O FCOMBUSTION TESTS ONMALATHION AND D D T

T A B L E ΠΙ

DISPOSAL AND DECONTAMINATION OF PESTICIDES

130

p r o c e s s i n g 5 0 0 l b / h of w a s t e . The waste containers a r e t r a n s f e r r e d b y c o n v e y o r to a s h r e d d e r , w h i c h p r o d u c e s 1 - 1 / 4 - i n . to 3 / 8 - i n . particles. The shredded m a t e r i a l is pneumatically conv e y e d to the c o m b u s t o r . The off-gas is cleaned by a particle s e p a r a t o r to r e m o v e the l a r g e r e n t r a i n e d p a r t i c l e s and then i s c l e a n e d b y a baghouse (not shown) b e f o r e i t i s e m i t t e d f r o m the stack. W i t h s u c h a u n i t , a ton of e m p t y p a p e r c o n t a i n e r s r e s u l t s i n o n l y 1 / 3 y d o f s p e n t salt. T h e spent s a l t i s d r a i n e d into a d r a i n c a r t and b u r i e d i n a C l a s s 1 dump. The s y s t e m is c o o l e d and then m o v e d to a n e w s i t e w h e r e f r e s h s a l t w o u l d be a d d e d to the c o m b u s t o r a n d the c y c l e r e p e a t e d . 3

Advantages of M o l t e n Salt C o m b u s t i o n T h e advantages o pesticide wastes are: 1)

I n t i m a t e c o n t a c t o f the hot m e l t , a i r , a n d w a s t e p r o v i d e s f o r c o m p l e t e a n d i m m e d i a t e d e s t r u c t i o n of the h a z a r d o u s material.

2)

N o a c i d i c g a s e o u s p o l l u t a n t s , e. g. , H C l f r o m c h l o r i n a t e d c o m p o u n d s s u c h as D D T a n d c h l o r d a n e a n d H S o r S 0 f r o m s u l f u r - c o n t a i n i n g c o m p o u n d s s u c h as m a l a t h i o n , a r e emitted. 2

2

3)

C o m b u s t i o n products a r e s t e r i l e and o d o r - f r e e .

4)

Sodium carbonate is stable, and n o n t o x i c .

5)

T h e p r o c e s s i s a p p l i c a b l e f o r a g r e a t v a r i e t y of o t h e r wastes. These include c h e m i c a l w a r f a r e agents, h a z a r d ous i n d u s t r i a l w a s t e s , h o s p i t a l wa'stes, c a r c i n o g e n i c m a t e r i a l s , and l o w - l e v e l r a d i o a c t i v e w a s t e s .

nonvolatile,

inexpensive,

MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

11 Binding and Release of Insecticide Residues in Soils T. W. FUHREMANN, E . P. LICHTENSTEIN, and J. K A T A N

1

Department of Entomology, University of Wisconsin, Madison, WI 53706

This paper summarizes data obtained recently in our laboratory and deals with the subject of soil-bound insecticide residues (1,2,3,4,5). Due to potential hazard more persistent insecticides have been replaced by less persistent compounds which seem to rapidly "disappear" from environmental components, such as soil. For many years depletion curves indicating the persistence or rate of disappearance of insecticides applied to soils have been published. Typical depletion curves (figure 1) were obtained in 1964 by our group after applying insecticides at the same rate, the same time and by the same methods to loam soil field plots near Madison, WI (6). These depletion curves indicated that compounds like aldrin or dieldrin persist in soil considerably longer than malathion, methylparathion or parathion. Frequently the decline in detectable residues has been associated with such terms as "disappearance", "loss" or "volatilization". However, the apparent disappearance of a pesticide from soil can be due to our inability to detect it's residues by conventional procedures. One reason a chemical cannot be detected is that the compound or its degradation products cannot be extracted from soil, thus they are 'invisible'. Those residues which can be extracted long after their application are the 'visible', persistent ones. The use of radiolabeled pesticides in laboratory studies has made it possible to detect unextractable soil residues. Combustion or strong hydrolysis of extracted soils can release these unextracted or bound C-residues. The problem of these bound residues, however is complicated since present methods for their release or liberation also result in the destruction or their identity. Insight into the mechanism of binding of pesticide residues to soils might shed some light on the nature of the residues and their potential release. Utilizing C-ring labelled parathion, the amount of unextractable or bound C-residues in a sandy and a loam soil were determined by combustion to CO , after the soils had been 14

14

14

14

2

0-8412-0433-0/78/47-073-131$05.00/0 © 1978 American Chemical Society

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

APPLIED: 5 LBS/5* ACRE C3J RRM.)

MONTHS Figure 1. Depletion curves depicting extractable residues of various insecticides applied at 6 kg/ha (concentration, 3.1 ppm) to ham soih in field plots

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

11.

FUHREMANN ET AL.

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133

extracted 3 times with benzene-acetone-methanol ( i l l s i ) ( l ) . Depletion curves of extractable parathion residues established during a 1-month incubation period (figure 2) were similar to those established under f i e l d conditions and resulted f i n a l l y i n recoveries of 30 to 36% of the insecticide dose applied to the loam s o i l . With a steady decrease of extractable residues over a 1-month incubation period, an increase of unextractable, bound l^C-residues occurred. This resulted f i n a l l y i n t o t a l recoveries of extracted plus bound residues, which amounted to 80% of the applied radiocarbon. Attempts to exhaustively extract these bound ^C-residues with a variety of solvents ranging i n polarity from benzene to water f a i l e d to further extract a significant amount. The rate of binding of ^ C residues was highest i a c t i v i t y of s o i l microorganiams irradiation or by autoclaving, the binding of ^C-parathion was reduced by 5$ to 8k%. Under anaerobic conditions, created by flooding s o i l s with water, the rate of binding of ^C-compounds doubled. The amount of bound residues decreased from 67% to 16% when s o i l s had been s t e r i l i z e d prior to the insecticide treatment and flooding. Reinoculation of this s o i l with microorganisms f u l l y reinstated the s o i l binding capacity. Incubation of the moist treated s o i l under nitrogen also increased the formation of bound residues, while incubation at 6°C rather than 27°C inhibited binding. When these experiments were repeated using ^ C - e t h y l rather than ^ C - r i n g labelled parathion, identical results were obtained which indicates that the bound residues apparently contain both the aryl and alkyl portions of the parathion molecule. This information led us to suspect that amino-parathion which contains both the a r y l and a l k y l portions of the molecule and i s formed under anaerobic conditions, might be the bound residue. In addition, data from our laboratory published i n 1964 (£) indicated that while parathion residues could be extracted and detected by thin-layer chromatography i n loam s o i l extracts after several weeks of s o i l incubation, amino-parathion and p-aminophenol, could not be recovered after a 1 day s o i l incubation. When this experiment was repeated i n 1976 using radiolabeled compounds we found that k9% of applied l^C-aminoparathion could not be extracted from the s o i l 2 hours after i t s application, while only 1.6% of applied parathion was bound i n 2 hours (2). Comparison of binding of a l l the nitro and amino analogs of parathion (figure 3) during a brief 2 hour incubation with loam s o i l indicated that i n a l l cases the amino compounds were bound to a much greater extent than the nitro-compounds. The role of microorganisms i n producing ^C-parathion derived bound residues and the mechanism of production of s o i l bound residues was also investigated by incubating ^ C - r i n g parathion i n soil-free culture media that had been inoculated with s o i l microorganisms (2). The amounts of ^C-compounds

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

-ι

1

1

1

1

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TOTAL (E+B)

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EXTRACTED (E)

<60| or < ο. Q UJ

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14 21 DAYS OF

-

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28 0 7 14 SOIL INCUBATION

21

28

Figure 2. Binding and extractability of C-Hng-parathion in two soils during a 28-day incubation period at 27°C (applied dose, 1 ppm). The amounts of parathion as determined by GLC in the loam soil extract were nearly identical to its radiocarbon content. (I) Sandy soil from cranberry bog; (II) loam soil. Curve B, bound parathion; Curve E, extracted parathion; and Curve Ε + B, the total. 14

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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135

Residues in Soils

i n c u l t u r e supernatants, t h a t upon a d d i t i o n t o s o i l became u n e x t r a c t a b l e , i n c r e a s e d up t o 12 hours of m i c r o b i a l c u l t u r e i n c u b a t i o n , when l\>3% of the a p p l i e d r a d i o c a r b o n was bound a f t e r a 2-hour s o i l i n c u b a t i o n p e r i o d ( f i g u r e 4 ) , The i n c r e a s e i n s o i l bound r e s i d u e s was c o r r e l a t e d with a decrease i n the amount of p a r a t h i o n i n the m i c r o b i a l c u l t u r e and a concomitant i n c r e a s e i n the appearance of the major degradation product, aminoparathion (figure 5). These data i n d i c a t e t h a t the p r o d u c t i o n of s o i l bound r e s i d u e s of p a r a t h i o n occurs i n two s t e p s . F i r s t microorganisms convert p a r a t h i o n t o aminoparathion and then t h i s amino-parathion becomes r a p i d l y bound t o s o i l . These s o i l bound r e s i d u e s a r e u n e x t r a c t a b l e and t h e r e f o r e not d e t e c t e d i n r o u t i n e r e s i d u e analyses. Experiments conducte 26 M% of the a p p l i e d r e s i d u e s had become s o i l - b o u n d w i t h i n one week of i n c u b a t i o n . Contrary t o r e s u l t s with - ^ C - p a r a t h i o n , b i n d i n g of ^ C - p h o r a t e r e s i d u e s d i d not i n c r e a s e a f t e r 1 week. F u r t h e r i n v e s t i g a t i o n s (4) p e r t a i n i n g t o the e x t r a c t a b i l i t y and formation of bound i ^ C - r e s i d u e s i n an a g r i c u l t u r a l loam s o i l were conducted with^the "non-persistent" i n s e c t i c i d e s " p e r s i s t e n t " i n s e c t i c i d e s ^ C - d i e l d r i n and C - p p'-DDT ( f i g u r e 6). With ^ C - m e t h y l p a r a t h i o n only 7% of the a p p l i e d r a d i o c a r b o n was e x t r a c t a b l e 28 days a f t e r s o i l treatment, while ^ C - b o u n d r e s i d u e s amounted t o k3% of the a p p l i e d dose. F i e l d s t u d i e s conducted i n I968-69 i n d i c a t e d t h a t fonofos has a h a l f - l i f e i n Piano s i l t loam s o i l under Wisconsin summer c o n d i t i o n s of about 28 days (8), In the l a b o r a t o r y t h i s loam s o i l was t r e a t e d with ^ C - r i n g or ^ C - e t h y l l a b e l l e d fonofos and incubated f o r v a r i o u s p e r i o d s . A f t e r 28 days about k7% of the r a d i o c a r b o n was e x t r a c t a b l e and most of t h i s was fonofos. However, u n e x t r a c t a b l e ^ C - r e s i d u e s i n c r e a s e d with i n c u b a t i o n time r e s u l t i n g a f t e r 4 weeks i n 35% of the a p p l i e d r e s i d u e s b e i n g s o i l bound. These r e s i d u e s were of course not d e t e c t e d i n the f i e l d study. R e s u l t s u s i n g ^ C - r i n g or ^ C e t h y l l a b e l l e d fonofos were very s i m i l a r i n d i c a t i n g that the bound r e s i d u e s probably d o n ' t i n v o l v e a cleavage product. Cont r a r y t o r e s u l t s obtained with p a r a t h i o n the b i n d i n g of fonofos does not appear t o be dependent on m i c r o b i a l a c t i v i t y . While i r r a d i a t i o n or a u t o c l a v i n g s o i l p r i o r t o i n s e c t i c i d e treatment and i n c u b a t i o n s i g n i f i c a n t l y reduced the b i n d i n g o f p a r a t h i o n and f l o o d i n g enhanced i t , fonofos b i n d i n g was not reduced by irradiation. A u t o c l a v i n g reduced b i n d i n g somewhat, p o s s i b l y due t o an a l t e r a t i o n of s o i l s t r u c t u r e and f l o o d i n g s l i g h t l y reduced fonofos b i n d i n g . Smaller amounts of s o i l - b o u n d r e s i d u e s had been formed with the " p e r s i s t e n t " i n s e c t i c i d e s amounting a f t e r 28 days t o only 6.5% of the a p p l i e d ^ C - d i e l d r i n and t o 25% of the a p p l i e d ^ C - p . p ' - D D T , while 95% and 72%, r e s p e c t i v e l y were s t i l l recovered by organic s o l v e n t e x t r a c t i o n . llf

f

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

Figure 3. Amounts of C-bound residues in soils, 2 hr after soil treatment at 1 ppm with C-para­ thion (PA), C-aminoparathion (Α-PA), C-paraoxon (PO), C-aminoparaoxon (A-PO), p- Cnitrophenol (PH), or p- C-aminophenol (A-PH) 14

14

14

14

14

14

14

34 1

0

/ 1

f

12

/

CELL DENSITY (I)

24

36

HOURS OF CULTURE

48

10.6 g ω

A

60

96

INCUBATION

Figure 4. Binding of C compounds to soil within 2 hr after the addition of supernatants obtained from 0-96-hr old microbial cultures, treated with C-parathion and inoculated (I) with soil microorganisms; ΝI — noninocufoted controk 14

14

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

FUHREMANN ET AL.

Ο

Insecticide

12

Residues in Soils

24

36

48

60

96

HOURS OF CULTURE INCUBATION Figure 5. Amounts of parathion and amino-parathion determined by gas liquid chromatography in benzene extracts of supernatants of microbial cul­ tures after treatment with C-ring-parathion at 10 ppm and incubation for 0-96 hr 14

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

UJ

100

9

^ j - A. C-METHYL PARATHION 14

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-

ο Lu CO

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DAYS OF INCUBATION IN A LOAM SOIL Figure 6. Binding and extractability of C-labeled insecticides in a silt loam soil during a 28-day incubation period, after soil treatment at 1 ppm. With the exception of C-methylparathion the amounts of extractable C-Dyfonate (fonofos), C-Dieldnn, and C-DDT, as determined by gas-liquid chromatography, were similar to the amounts of extractable radiocarbon. For comparison purposes, data are inserted in A for the bound residues of Cparathion in soil. Ε — extracted; Β = bound; Τ = total of Ε B. 14

14

14

14

14

14

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

11.

FUHREMANN ET AL.

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Residues in Soib

139

They d i f f e r e d from t h e organophosphorus compounds i n t h e i r r e l a t i v e l y low b i n d i n g p r o p e r t i e s and t h e i r h i g h e x t r a c t a b i l i t y from s o i l s . The q u e s t i o n o f t h e p o t e n t i a l b i o l o g i c a l a v a i l a b i l i t y of bound i n s e c t i c i d e r e s i d u e s was i n v e s t i g a t e d (4) by t e s t i n g t h e i n s e c t i c i d a l a c t i v i t y o f bound r e s i d u e s from ^ C - f o n o f o s and l^G-methylparathion t r e a t e d s o i l s w i t h f r u i t f l i e s ( D r o s o p h i l a ) . With s o i l s c o n t a i n i n g u n e x t r a c t a b l e r a d i o c a r b o n a t t h e i n s e c t i c i d e e q u i v a l e n t o f 3 ppn, no m o r t a l i t i e s were observed d u r i n g a 24-hour exposure p e r i o d t o t h e s o i l and only s l i g h t m o r t a l i t i e s occurred d u r i n g an a d d i t i o n a l 48-hour exposure p e r i o d . However, w i t h s o i l s t o which the i n s e c t s were exposed immediately f o l l o w i n g t h e i n s e c t i c i d e a p p l i c a t i o n a t t h e same c o n c e n t r a t i o n as t h e u n e x t r a c t a b l e radiocarbon (3 ppm) 50$ f t h f l i e had d i e d w i t h i n 2-3 hours hours a f t e r s o i l treatmen methylparathion appears t h e r e f o r e , t h a t bound i n s e c t i c i d e r e s i d u e s a r e not only unext r a c t a b l e , but they a r e a l s o l e s s a c t i v e b i o l o g i c a l l y . Experiments were a l s o conducted t o study t h e r e l e a s e and a v a i l a b i l i t y of unextractable, soil-bound residues o f ^ C - r i n g met hy l p a r a t h i on and t h e p o t e n t i a l p i c k up o f these ^ C - r e s i d u e s by earthworms and oat p l a n t s (j>). Data from t h i s i n v e s t i g a t i o n i n d i c a t e that unextractable soil-bound i n s e c t i c i d e residues are not e n t i r e l y excluded from environmental i n t e r a c t i o n . A f t e r i n c u b a t i o n o f s o i l t r e a t e d w i t h ^ C - m e t h y l p a r a t h i o n f o r 14 days, and exhaustive s o l v e n t e x t r a c t i o n s , bound r e s i d u e s remaining i n t h i s s o i l amounted t o 3 2 . 5 $ of t h e a p p l i e d i n s e c t i c i d e . However, a f t e r worms had l i v e d f o r 2 t o 6 weeks i n t h i s p r e v i o u s l y e x t r a c t e d s o i l c o n t a i n i n g only bound r e s i d u e s o r s e v e r a l crops of oats had grown i n i t , s i z a b l e amounts o f ^ C - r e s i d u e s were found i n these organisms. Earthworms which l i v e d i n t h e s o i l f o r 6 weeks contained a t o t a l o f 2.7$ of t h e ^ C - r e s i d u e s which c o u l d not be e x t r a c t e d from these s o i l s , w h i l e 3 crops of oats p l a n t s each grown f o r 2 weeks contained a t o t a l o f 5 · ! $ . The m a j o r i t y o f p r e v i o u s l y s o i l - b o u n d ^ C - r e s i d u e s taken up by earthworms (58-66$) a g a i n became bound w i t h i n these worms, w h i l e most (82-95$) o f t h e ^ C - r e s i d u e s i n oat p l a n t s were e x t r a c t a b l e . Greens o f oat p l a n t s contained 46-62$ of t h e ^ C - r e s i d u e s recovered from p l a n t s . Most o f t h e ^ C - r e s i d u e s i n oat greens were benzene-soluble w h i l e most o f t h e ^ C - r e s i d u e s i n t h e seeds and r o o t s were w a t e r - s o l u b l e . Because s o i l - b o u n d i n s e c t i c i d e r e s i d u e s can be r e l e a s e d from s o i l by these organisms any l o s s i n t o x i c i t y due t o b i n d i n g s h o u l d not be regarded as permanent. Even i f r e l e a s e o f nont o x i c compounds occurs, i n t e r a c t i o n w i t h other chemicals i n t h e environment cannot be d i s r e g a r d e d . The r e l e a s e and p o t e n t i a l b i o l o g i c a l a c t i v i t y of these bound r e s i d u e s c e r t a i n l y warrants f u r t h e r study. I n view o f t h e above f i n d i n g s , t h e e x p r e s s i o n "disappearance" and " p e r s i s t e n c e " o f p e s t i c i d e s , so w i d e l y used d u r i n g t h e l a s t two decades, should be reassessed t o c o n s i d e r the bound products.

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

140

Literature Cited 1. Katan, J., Fuhremann, T.W., L i c h t e n s t e i n , E.P., Science (1976) 193(4256) 8 9 1 - 8 9 4 .

2 . Katan, J., L i c h t e n s t e i n , E.P., J. Ag. Food Chem. (1977) 2 5 ( 6 ) 1404-1408.

3.

L i c h t e n s t e i n , E.P., L i a n g , T.T., Fuhremann, T.W., J. Ag. Food Chem. (1978) Submitted.

4 . L i c h t e n s t e i n , E.P., Katan, J., Anderegg, B.N., J. Ag. Food Chem. (1977)

25(1)

43-47.

5. Fuhremann, T.W., L i c h t e n s t e i n , E.P., J. Ag. Food Chem. (1978) I n Press. 6. L i c h t e n s t e i n , E.P., Pure A p p l . Chem. (1975) 42(1) 113-118. 7 . L i c h t e n s t e i n , E.P. S c h u l z K.R. J. Econ Entomol (1964) 57(5)

618-627.

8. S c h u l z , K.R., L i c h t e n s t e i n , E.P., J. Econ Entomol. 64(1)

(1971)

283-287.

Footnotes 1/ Present Address: Hebrew U n i v e r s i t y , F a c u l t y o f A g r i c u l t u r e , Rehovot, Israel. 2/ Research supported by t h e C o l l e g e o f Agricultural and Life S c i e n c e s , U n i v e r s i t y o f Wisconsin, Madison and by grants from t h e Environmental P r o t e c t i o n Agency (R 804920) and the N a t i o n a l Science Foundation (DEB76-08869). Contribution by P r o j e c t 1387 from t h e Wisconsin Agricultural Experiment S t a t i o n as a c o l l a b o r a t o r under North C e n t r a l R e g i o n a l Cooperative Research P r o j e c t 96, entitled "Environmental I m p l i c a t i o n s o f Pesticide Usage". MARCH 23, 1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

12 Dieldrin Elimination from Animal Tissues K. L. DAVISON U.S. Department of Agriculture, S.E.A. Metabolism and Radiation Research Laboratory, Fargo, ND 58102

In 1974, dieldrin residues above U. S. Food and Drug Administration tolerances for human consumption were discovered in body fat of turkeys from two flocks in North Dakota. Turkeys from one of these flock d investigat th effective ness of phenobarbital dieldrin. Phenobarbital did not cause a detectable change in the rate of dieldrin elimination but did stimulate our most recent investigations of dieldrin elimination from animal tissues. This report provides a brief review of recent research on dieldrin elimination from animals and a summary of attempts to remove dieldrin from chickens and turkeys. A thorough review of dieldrin accumulation, storage, metabolism and elimination by animals is not intended. Brief Review When ingestion of dieldrin remains constant, storage of dieldrin in body tissues, predominately adipose tissue, apparently plateaus (1). Presumably, a steady state has occurred, and excretion of dieldrin or its metabolites equals ingestion. The time required to reach this steady state was 6 weeks in rats and 22 to 26 weeks in chickens. A steady state for storage and excretion probably also occurs for other chlorinated hydrocarbon insecticides when ingestion remains constant. Heath and Vandekar (2) showed that fecal elimination of [ Cl]dieldrin, or its metabolites, was increased in rats during intermittent periods of starvation. The [ Cl]dieldrin accumulated in adipose tissue of the rats when it was fed to them before the periods of starvation. In the early 1960s, milk from a number of Maryland dairy farms contained excessive amounts of heptachlor. The heptachlor residues were traced to heptachlor-contaminated forage eaten by the cows. At that time, USDA officials suggested starvation as a means of removing the heptachlor residues from the contaminated cattle, but apparently 36

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the i d e a was not t e s t e d . More r e c e n t l y , Cook and h i s colleagues a t Michigan State U n i v e r s i t y recommended using a combination of c h a r c o a l and phénobarbital f o r removing d i e l d r i n residues from c a t t l e . They observed t h a t c h a r c o a l f e d c o n c u r r e n t l y w i t h d i e l d r i n increased the amount of d i e l d r i n e l i m i n a t e d i n the feces ( 3 ) . They a l s o observed that phénobarbital induced h e p a t i c mixed-function oxidases i n c a t t l e (k). Cook never conducted c o n t r o l l e d e x p e r i ments w i t h phénobarbital alone f o r removing d i e l d r i n residues from c a t t l e , but he d i d t r y using the combination of phénobarbi t a l and carbon on a farm on which d a i r y c a t t l e were contaminated w i t h d i e l d r i n (_5). The herd was s p l i t i n t o two groups. One group was untreated and the other group was t r e a t e d w i t h both phénobarbital and c h a r c o a l r a p i d l y i n m i l k from t r e a t e cows. Phénobarbital i s e f f e c t i v e i n removing d i e l d r i n r e s i d u e s from r a t s (6) and p i g s ( 7 ) . When f e d c o i n c i d e n t w i t h d i e l d r i n , c h a r c o a l was e f f e c t i v e i n reducing the amount o f d i e l d r i n accumulated i n body t i s s u e s of r a t s ; but once d i e l d r i n had accumulated i n body t i s s u e s , c h a r c o a l feeding had l i t t l e e f f e c t on reducing these r e s i d u e s ( 6 ) . Summary of Research w i t h Chickens and Turkeys When the d i e l d r i n r e s i d u e s were found i n body f a t o f turkeys i n two North Dakota f l o c k s i n 1974, the d e c l i n e i n r e s i d u e l e v e l s was f o l l o w e d i n one of the f l o c k s . The~values obtained f i t the equation Y = 5.34 - 0.187X + 0.0Ό252Χ 0.000Ό114Χ , where Y i s the c o n c e n t r a t i o n of d i e l d r i n i n body f a t i n ppm^and X i s the time i n days. The c o r r e l a t i o n coef­ f i c i e n t , R , f o r t h i s equation was 0.989. C o r r e l a t i o n coef­ f i c i e n t s f o r f i r s t - o r d e r and q u a d r a t i c equations were 0.868 and 0.957, r e s p e c t i v e l y . C l e a r l y , i n t h i s f l o c k o f t u r k e y s , the c u b i c equation described the change i n r e s i d u e l e v e l s w i t h time b e t t e r than the f i r s t - o r d e r o r q u a d r a t i c equations. A t l e a s t two f a c t o r s a f f e c t e d the r e s i d u e l e v e l s . The f i r s t f a c t o r was d i l u t i o n by growth, and the second was d i e l d r i n e l i m i n a t i o n . A f t e r the d i s c o v e r y of the d i e l d r i n r e s i d u e s i n t u r k e y s , research was begun t o f i n d ways of e l i m i n a t i n g d i e l d r i n r e s i d u e s from chickens and turkeys. Because of h i g h g r a i n p r i c e s i n 1974, the feeding regimen f o r turkeys i n North Dakota was screenings ( p r i m a r i l y seed of green and y e l l o w f o x t a i l ) p l u s a 40% p r o t e i n , commercial supplement. An experiment (8) was conducted w i t h turkeys r a i s e d a t North Dakota State U n i v e r s i t y . The turkeys were f e d the screenings p l u s supplement d i e t used by the turkey growers. D i e l d r i n was f e d i n t h i s d i e t f o r 5 days t o b u i l d r e s i d u e s i n the bodies o f the t u r k e y s , and then removed from the d i e t . The turkeys were then d i v i d e d i n t o f i v e groups. One group was the c o n t r o l and was f e d the screenings p l u s

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supplement d i e t f o r 68 days. One group was s t a r v e d f o r 5 days and then fed the c o n t r o l d i e t . Another group was given about 200 mg of sodium b a r b i t a l per turkey i n t h e i r d r i n k i n g water. The 4th group was fed a h i g h f i b e r d i e t (33% a l f a l f a meal i n the c o n t r o l d i e t ) , and the 5th group was fed a h i g h energy h i g h p r o t e i n d i e t . These treatments d i d not d e t e c t a b l y reduce r e s i d u e s below those of the c o n t r o l turkeys. A second experiment (8) was conducted w i t h turkeys that had been fed d i e l d r i n t o b u i l d r e s i d u e s i n t h e i r bodies. These turkeys were d i v i d e d i n t o two groups. The f i r s t group was the c o n t r o l and was fed a normal r a t i o n f o r 61 days. The second group was subjected to three periods of s t a r v a t i o n (7, 7 and 4 days) i n t e r r u p t e d by periods of feeding (7, 12 and 24 days). P e r i o d i c s t a r v a t i o n wa e f f e c t i v i a c c e l e r a t i n th d e c l i n i n both the c o n c e n t r a t i o amount of d i e l d r i n i n the carcasses o the t u r k e y s . A s e r i e s of balance experiments were c o n d u c t e ^ w i t h chickens (9) and turkeys (10) g i v e n d i e l d r i n and [ C ] d i e l d r i n . Severe s t a r v a t i o n , c h a r c o a l , cholestyramine (a r e s i n ) , probucol (a c h o l e s t e r o l lowering drug), C h o l i s t i p o l (a r e s i n ) , imbiber beads (an absorbent), Dowex SBR-C1 r e s i n and Dowex XFS-4022 r e s i n were t e s t e d f o r t h e i r a b i l i t y t o a c c e l e r a t e the e l i m i ­ n a t i o n of d i e l d r i n r e s i d u e ^ . Severe s t a r v a t i o n was e f f e c t i v e i n lowering d i e l d r i n o r [ C ] d i e l d r i n r e s i d u e s i n e i t h e r chickens o r turkeys. S t a r v a t i o n was e f f e c t i v e o n l y i f severe enough t o reduce the amount of body l i p i d s t o 10% or l e s s of the carcass dry matjer. Cholestyramine was e f f e c t i v e i n low­ e r i n g d i e l d r i n or [ C ] d i e l d r i n r e s i d u e s i n chickens, but was not e f f e c t i v e i n t u r k e y s . The other m a t e r i a l s t e s t e d were not e f f e c t i v e i n e i t h e r chickens o r t u r k e y s .

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8.

Davison, K. L. Bull. Environ. Contam. Toxicol. (1973) 10, 16-24. Heath, D. F., and Vandekar, M. Brit. J. Industr. Med. (1964) 21, 269-279. Wilson, Κ. Α., and Cook, R. M. J. Agr. Food Chem. (1970) 18, 437-440. Cook, R. Μ., and Wilson, K. A. J . Agr. Food Chem. (1970) 18, 441-442. McGuire, J. R. Des Moines Sunday Register (July 20, 1969) p. 1-F. Engebretson, Κ. Α., and Davison, K. L. Bull. Environ. Contam. Toxicol. (1971) 6, 391-400. Dobson, R. C., and Baugh, E. R. Bull. Environ. Contam. Toxicol. (1976) 16, 567-571. Sell, J. L. , Davison, K. L . , and Bristol, D. W. Poultry Sci. (1977) 56, 2045-2051.

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9. 10.

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K. L . , and Sell, J. L. Arch. Environ. Contam. (Accepted 1978). K. L . , and Sell, J. L. Arch. Environ. Contam. (Accepted 1977).

Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the U. S. Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. MARCH 23,

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In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

13 Chlorine-Mercury Interactions in Mercury Derivatives of Poly-Chlorinated Phenols and Other Chlorocarbons 1

GARY WULFSBERG , JOHN GRAVES, JUNE GRIFFITHS, and DON ESSIG Northland College, Ashland, WI 54806 R.J.C.BROWN Queen's University, Kingston, Ontario

For some time, we have been interested i n the metal derivatives of chlorocarbons, which we have studied especially by the technique of chlorine-35 nuclear quadrupole resonance spectroscopy (NQR). Our spectra to date have often turned up evidence of direct (albeit weak) metal-chlorin suggesting that, under certai migh be able to act as ligands for metals. The primary purpose of this study is to elucidate the nature of this metal-chlorine i n t e r action. However, we also hope that, if we can determine optimum conditions for coordination of chlorocarbons, complexes of metal salts with chlorocarbons may be formed which would show enhanced rates of nucleophilic substitution of chloride by the anion of the metal s a l t , thus opening another possible route to the degradation of waste chlorocarbon pesticides. (This would, of course, be analogous to the s i l v e r - i o n catalyzed nucleophilic substitution reactions of a l k y l halides.) (2) Our primary strategy i n this study has been to prepare metal derivatives of chlorocarbons having two or more chlorines which are chemically equivalent unless there is a metal-chlorine i n t e r action. As an example from Figure 1, we have prepared metal derivatives of 2,6-dichlorophenol. Intramolecular metal-chlorine interaction will create different electronic environments at the two chlorine atoms. Cl NQR is very sensitive to such d i f f e r ences, and it may be predicted (1) that the NQR frequency of the interacting chlorine will be lower than the frequency of the normal chlorine. The degree to which the two frequencies are s p l i t should reflect approximately the strength of the interaction i n the ground state, as long as the interaction is much weaker than the C-Cl bond strength. A frequency s p l i t t i n g of less than 2%, however, is not reliable evidence of such an interaction: NQR is done on c r y s t a l l i n e s o l i d s , and i n c r y s t a l l a t t i c e s the effects of the electrons i n neighboring molecules can vary the observed NQR frequencies by up to 2% i n covalent molecules. As the NQR frequencies of the chlorocarbons under study scan the range 34-40 MHz, we take any 35

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Figure 1. Types of mercury derivatives of chlorocarbons studied in this work. Possible chlorine-mercury interactions are indicated by broken lines ( ), and the size of ring produced by such an interaction is indicated by the number below each figure.

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frequency lowering o f more than 0.8 MHz as an i n d i c a t o r o f an i n t e r a c t i o n o f that c h l o r i n e w i t h another atom b e s i d e s the carbon t o which i t i s bound. The f i r s t p a r t o f our s t u d y , which i s e s s e n t i a l l y complete, considers the geometrical requirements o f the i n t e r a c t i o n . An i n t r a m o l e c u l a r i n t e r a c t i o n would complete a " r i n g " w i t h i n the molecule, and we might expect t h a t some s i z e s o f r i n g s would be p r e f e r r e d t o o t h e r s . I n the s o l i d s t a t e , i n t e r m o l e c u l a r i n t e r ­ a c t i o n s may a l s o occur. Extended, weak i n t e r m o l e c u l a r i n t e r ­ a c t i o n s should be weakened by expanding the l a t t i c e , as by warm­ i n g the c r y s t a l o r reducing the pressure on i t . These e x p e r i ­ ments, we would expect, would reduce the s p l i t t i n g o f the NQR frequencies o f the two c h l o r i n e s i n our molecule, i f the i n t e r ­ action i s intermolecular We expect no c o n s i s t e n t e f f e c t on the s p l i t t i n g i f the i n t e r a c t i o We have s t u d i e d th the v a r i a b l e - p r e s s u r e NQR s p e c t r a o f the mercury d e r i v a t i v e s o f the c l a s s e s o f chlorocarbons shown i n Figure 1. I n d i c a t e d below each o f the drawings i s the s i z e o f r i n g expected i f i n t r a m o l e ­ c u l a r i n t e r a c t i o n occurs. F i g u r e 2 shows the r e s u l t s f o r the t r i c h l o r o m e t h y l m e r c u r i a l s , RHgCCl3, * ^ organic trichloromethanes as models. The observed frequencies were each s u b t r a c t e d from the highest f r e ­ quency (which i s presumably t h a t o f a n o n - i n t e r a c t i n g c h l o r i n e ) to give the s p l i t t i n g s i n d i c a t e d along the a b s c i s s a . Most s p l i t ­ t i n g s o f the NQR frequencies o f the model compounds are s m a l l ( l e s s than 0.8 MHz). On changing the temperature o f NQR measure­ ment from 77 Κ t o room temperature, there i s no c o n s i s t e n t change i n these s p l i t t i n g s . (This i s i n d i c a t e d along the v e r t i c a l a x i s . ) A number o f m e r c u r i a l s , however, show s p l i t t i n g s o f g r e a t e r than 0.8 MHz, which suggests the presence o f a chlorine-mercury i n t e r ­ a c t i o n . Such l a r g e s p l i t t i n g s are c o n s i s t e n t l y reduced a t room temperature, which suggests that i n t e r m o l e c u l a r chlorine-mercury i n t e r a c t i o n s are being observed. A v a r i a b l e - p r e s s u r e NQR measure­ ment on b i s ( t r i c h l o r o m e t h y 1 ) m e r c u r y g i v e s r e s u l t s which are a l s o c o n s i s t e n t w i t h t h i s s u g g e s t i o n — t h e s p l i t t i n g i s increased by i n c r e a s i n g the pressure. A c r y s t a l s t r u c t u r e has been reported (6) f o r one o f these m e r c u r i a l s (trichloromethylmercury bromide), but the data on Hg...Cl nonbonded d i s t a n c e s can be i n t e r p r e t e d i n d i f f e r e n t ways w i t h respect t o i n t e r a c t i o n s . (1) In Figure 3 ( c l o s e d c i r c l e s ) are shown r e s u l t s f o r a s e r i e s of organic d e r i v a t i v e s o f 2,6-dichlorophenol, and 2 , 6 - d i c h l o r o t h i o p h e n o l . Only c r y s t a l l a t t i c e s p l i t t i n g s should be present; c o n s i s t e n t w i t h t h i s a l l s p l i t t i n g s are l e s s than 0.8 MHz—indeed they are l e s s than 0.4 MHz. There i s no systematic e f f e c t o f temperature on these s p l i t t i n g s . The t r i a n g l e s i n F i g u r e 3 represent d a t a o f Kravstov e t a l (8) f o r a number o f 4 - s u b s t i t u t e d 2,6-dichlorophenols. Hydrogen bonding i s known t o occur i n t h i s type o f compound, and i n v o l v e s an(

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Figure 2. NQR frequency splittings for trichloromethyl compounds at 77K compared with the reduction of these splittings at Z73K. ( In many cases this splitting is extrapolated, as the frequencies fade out below 273K.) Open circles (O) indicate data for trichloromethylmercuriab CCl,HgR with R groups as indicated: A, CCl ; B, C H ; C, CI; D, Br; E, CI + CH O(CH CH O) CH coordinated to Hg. Closed circles (·) indicate data for organic trichloromethanes CCl R with R groups as indicated: F, H; G, CH ; H, CH(OH),; I, CH(OH) (NH ); J, CCl ; K, cyclo-C\Ch(CCl ); L, cycfo-C Cl (= CCl ) (CCl ); M, C H Cl-4, N, C Cl ; P, CH(OH) (OC H ); R, CH(OH) (OCH ). Data are taken from References 1,3,4, and 5. s

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Figure 3. NQR frequency splittings for 2,6-dichlorophenoxy and 2,6-dichlorothiophenoxy compounds at 77K compared with the reduction of these splittings at 273K. Closed circles (·) indicate data for nonmetal derivatives in which the chlorine is not being affected by hydrogen bonding; triangles (A) indicate data for phenols and thiophenols with hydrogen bonding to the chlorine atom in question; and open circles (O) are for mercurials. Data points for 4-X-C H Cl -2,6-YR are as follows (symbol « X, Y, R); A = H,0, CH ; Β = F, O, H; C — CN, O, H; D — NO,, O, CH ; Ε = F, Ο, CHs; F — H, S, CH ; G — H, Ο, H; H — C H , Ο, H ; I — N H , O, H ; / — CI, Ο, H ; Κ — I, O, H ; L « CHO, O, H ; M — H , O, HgC H ; N — H , O, HgCH C H ; Ρ «= H , O, HgC H - [CH(CH ) ] - 2,4fi; R - H , O, HgC H>N(CH ),4; S — H , S, HgC H . Data taken from References 7, 8, 9, and 10 and this work (Table I). 6

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I n t r a m o l e c u l a r five-membered r i n g formation w i t h one ortho c h l o ­ r i n e . S u b s t a n t i a l s p l i t t i n g s of the NQR frequencies of the 2 and 6 c h l o r i n e s a l s o r e s u l t from hydrogen bonding (11) ; these are not c o n s i s t e n t l y reduced i n magnitude by r a i s i n g the temperature. This p r e d i c t i o n should h o l d f o r an i n t r a m o l e c u l a r l y - i n t e r a c t i n g c h l o r i n e r e g a r d l e s s of whether i t i s i n t e r a c t i n g w i t h hydrogen or a metal. The open c i r c l e s of F i g . 3 (and Table 1) show the r e s u l t s to date f o r the mercury d e r i v a t i v e s of 2,6-dichlorophenol and the t h i o analogue. The s p l i t t i n g s range up t o 1.2 MHz, so i n t e r ­ a c t i o n s are e v i d e n t l y present. Most, but not a l l , of these p o i n t s seem t o be d i s t r i b u t e d about zero on the v e r t i c a l a x i s , suggest­ ing t h a t the i n t e r a c t i o n i s u s u a l l y i n t r a m o l e c u l a r . (There can, of course, be i n t e r m o l e c u l a i n t e r a c t i o n i a d d i t i o t o i place of, intramolecula has been done on two compound y here, which shows the presence of i n t r a m o l e c u l a r c o o r d i n a t i o n w i t h mercury (12) and copper (13). TABLE 1.

NQR

FREQUENCIES OF MERCURY 2,6-DICHL0R0PHEN0XIDES AT SELECTED TEMPERATURES ν, 273K ν, 195K V , 77K S u b s t i t u e nt on Hg 34.476 34.682 Phenyl 34.925 33.500 33.752 34.044 34.299 34.608 35.004 Benzyl 33.472 33.708 33.995 34.159 4-D imethylaminopheny1 34.892 34.495 32.897 33.230 33.657 b 34.991 2,4,6-Tris(isopropyl)phenyl 35.244 b 34.014 34.147 a. Frequencies, i n MHz, at temperature i n d i c a t e d . 77K s p e c t r a were f i r s t reported i n r e f . 7. b. S i g n a l s not detected at 195K or h i g h e r . Frequency l i s t e d was obtained at 110K. a

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Time does not a l l o w us to go through the other cases i n d e t a i l . To summarize our r e s u l t s , however, the pentachlorophenylm e r c u r i a l s (Figure 1 ) , which might form 4-membered p l a n a r r i n g s through i n t r a m o l e c u l a r i n t e r a c t i o n , seem to do so. By way of c o n t r a s t , the p e n t a c h l o r o c y c l o p e n t a d i e n y l m e r c u r i a l s could form a 3-membered r i n g v i a t h e i r a l l y l i c c h l o r i n e , and 4-membered nonp l a n a r r i n g s v i a two v i n y l i c c h l o r i n e s . From the NOR evidence, i n t e r a c t i o n s w i t h mercury occur w i t h both types of c h l o r i n e ( 1 ) , but i n both cases these are i n t e r m o l e c u l a r . Hence, the NQR e v i ­ dence to date suggests t h a t , f o r an i n t r a m o l e c u l a r c h l o r i n e mercury i n t e r a c t i o n to occur, there must be a five-membered or a p l a n a r four-membered r i n g formed. These r i n g s , indeed, are the more f a v o r a b l e ones f o r overlap of the c h l o r i n e l o n e - p a i r e l e c ­ trons w i t h vacant metal o r b i t a l s . The r e s u l t s , however, do not exclude an e l e c t r o s t a t i c i n t e r p r e t a t i o n of the i n t e r a c t i o n .

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In order t o probe t h i s matter f u r t h e r , we are p r e p a r i n g the chlorophenoxides o f a number o f other metals and s t u d y i n g them by NQR and by other s p e c t r o s c o p i c methods. Some metals we a r e choosing f o r t h e i r p r o p e n s i t y t o engage i n i o n i c bonding o n l y ; others we are s e l e c t i n g f o r t h e i r r e p u t a t i o n f o r having vacant o r b i t a l s a v a i l a b l e f o r c o v a l e n t bonding. Some should be "hard", and others " s o f t " . To date we have some p r e l i m i n a r y r e s u l t s : the T l , Na+, and K " chlorophenoxides s t u d i e d so f a r show no s i g n i f i c a n t (>0.8 MHz) s p l i t t i n g of the 2 and 6 c h l o r i n e NQR s i g n a l s , w h i l e t h e copper ( I I ) chlorophenoxides show q u i t e l a r g e s p l i t t i n g s (up t o 2 MHz). Any p r e d i c t i o n s as t o which metal might have the most promise i n promoting the degradation of waste chlorocarbons must, however, await c o n s i d e r a b l y more work. We wish t o thank th C o l l e g e Science Grant i M i s c i k o w s k i , Wei Lan Wong, and Tim Bonner f o r t h e i r p r e l i m i n a r y work on the d e r i v a t i v e s o f o t h e r metals. +

4

Literature Cited 1. Wulfsberg, G., West, R., and Rao, V.N.M., J. Organometal. Chem., (1975) 86, 303. 2. Ingold, C.K., "Structure and Mechanism in Organic Chemistry," 2nd. ed., 479-83, Cornell University Press, Ithaca, 1969. 3. Biryukov, I.P., Voronkov, M.G., and Safin, I.A., "Tables of Nuclear Quadrupole Resonance Frequencies," Israel Program for Scientific Translations, Jerusalem, 1969. 4. Hashimoto, Μ., and Mano, Κ., Bull. Chem. Soc. Jap., (1972) 45, 706. 5. Kiichi, T., Nakamura, Ν., and Chihara, Η., J. Magn. Reson., (1972) 6, 516. 6. Babushkina, T.A., Bryukhova, E.V., Velichko, F.K., Pakhomov, V.I., and Semin, G.K., J. Struct. Chem., (1968) 9, 153. 7. Kravtsov, D.N., Zhukov, A.P., Faingor, B.A., Rokhlina, E l . Μ., Semin, G.K., and Nesmeyanov, G.K., Bull. Acad. Sci. USSR, Div. Chem. Sci., (1968) 1611. 8. Kravtsov, D.N., Zhukov, A.P., Babushkina, T.A., Bryukhova, T.A., Golovchenko., L.S., and Semin, G.K., Bull. Acad. Sci. USSR, Div. Chem. Sci., (1972) 1655. 9. Kravtsov, D.N., Semin, G.K., Zhukov, A.P., Babushkina, T.A., Rokhlina, E.M., and Nesmeyanov, A.N., Theor.Exper.Chem., (1972) 9, 401. 10. Pies, W., and Weiss, Advances in Nucl. Quad. Resonance, (1974) 1, 57. 11. Baker, A.W., and Kaeding, W.W., J . Am. Chem. Soc., (1959) 81, 5904. 12. Kuz'mina, L.G., Bokii, N.G., Struchkov, Yu. T., Kravtsov, D. Ν., and Golovchenko, L.S., J. Struct. Chem., (1973) 14, 463. 13. Wong, R.Y., Palmer, K . J . , and Tomimatsu, Υ., Acta Cryst. Sec. B, (1976) B32, 567. APRIL 5,

1978

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

INDEX A

1 4

Agent orange 7,8 Air manifold, poly (vinyl chloride ) compressed 105 Air-sparged molten salt combustor, hydraulic simulation of 121 Aldrin 16,22,28,131 hydrodechlorination products of .... 29 photooxidation of 17 Alkaline hydrolysis of organophos phate compounds 7 Amino-parathion 133,13 p-Aminophenol 133 Amitrole 16 Animal tissues, dieldrin elimination from 141 Aroclor 1248 24 Aromatic halides, photochemical reduction of 3 Atomic radiation 22 Atrazine process wastes 76

Β Bacillus cereus, toxic effect of rose bengal on 47 Baghouse "118 Baygon 77 Bench-scale molten salt combustor 120,122 Benzenoid compounds 16 Binding of 14

C

compounds to soil -labeled insecticides -ring parathion insecticide residues in soils Bioconversion technology Biodetoxification of pesticides Boll weevil light-independent mortality of the Bound residues, insecticidal activity of

136 138 134 131 73 78 37 39 139

C -bound residues compounds to soil, binding of -dieldrin -fonofos (Dyfonate) -labeled insecticides, binding of -labeled insecticides, extractibility of

136 136 135 135 138 138

C (continued) -methylparathion -parathion -phorate -ring labeled parathion parathion, binding of parathion, extractibility -residues extraction of

mass spectral data for Carbon disulfide evolution method .... Catalytic hydrodechlorination of polychlorinated hydrocarbons .... Chemical(s) degradation treatment processes used at horticulture station Chick-edema Chlorinated pesticides, combustion products of Chlorination, exhaustive Chlorine conversion Chlorine-mercury interactions in mercury derivatives Chlorobenzoic acids, photolysis of Chlorobenzonitriles, photolysis of Chlorocarbons, mercury derivatives of Chlorodioxins photochemical destruction of Chlorohexanes Chlorohydrocarbon wastes Chlorolysis Chlorophenol(s) methyl ethers, photolysis of Chlorotoluenes, photolysis of Cholestyramine Chromatography of rose bengal, highperformance liquid Combustible container materials, molten salt combustion of Combustion products of chlorinated pesticides .. products of sulfur-containing pesticides results with D D T results with malathion

153

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

135 135 135 131 134 134 131 133 90 82 24 24 115 14 75 101 1 95 76 33 145 19 19 146 15 1 2 76 76 1 19 19 143 40 125 95 93 127 127

DISPOSAL AND DECONTAMINATION OF PESTICIDES

154

Combustion (continued) of simulated pesticide containers, off-gas analysis for 126 temperatures 94,95,96 tests on DDT, results of 129 on malathion, results of 129 results of 123 Concrete-lined disposal pit 104 Cyclodiene insecticides 16 D DDE 24 hydrodechlorination of 27 irradiation of 18 photolysis half-life for 2 DDT 24,7 combustion results with 127 irradiation of 18 results of combustion tests on .. 129 Dechlorination, reductive 2 Decomposition followed by volatilization 85 Decomposition without volatilization 85 Decontamination of pesticides: photodecomposition 13 Deep-well injection 81 Depletion curves of extractable parathion residues 133 Detoxification of hazardous wastes 49 technology for 100 methyl bromide 66 pesticides 49 technology for 100 wastes 13 2,6-Dichlorophenol 147 mercury derivatives of 150 2,6-Dichlorophenoxy compounds, NQR frequency splittings for 149 2,6-Dichlorothiophenol 147 2,6-Dichlorothiophenoxy compounds, NQR frequency splittings for 149 Dieldrin 16,22, 28,131 elimination from animal tissues 141 hydrodechlorination products of .... 29 residues 141 2, -Dihydrogen mirex, pyrolysis of 114 5,10-Dihydrogen mirex, pyrolysis of .. 114 Dioxins 10 Disposal or mirex residues 112 of pesticides: photodecomposition . 13 pit, concrete-lined 104 system, portable molten salt 127 techniques 49 Drosophila 139 Dye-induced toxicity 37

Dye-sensitized photooxidation Dyfonate, C-fonofos

37 135

14

Ε Endrin 22 Eosin yellowish 38 Erythrosin Β 38 Esteron 7 Excited singlet state 37 Exhaust temperatures 94,95,96 Exhaustive chlorination 76 Expanded-scale microwave plasma system 51,55 Expanded-scale plasma reactor 60 Extractibility of C-labeled insecticides 138 14

depletion curves of

133

F Face fly · · · 37 Fenaminosulf 20 Fire ant, light-independent mortality of the 39 Fire ants, mortality of 36 Florisil 82 Fluorescein 38,41 Fluorescence 37 Fluorescent pseudomonads 78 Fungicide(s) 101 analysis 82 thermal degradation of 81 G Gas chromatography Girdler G49 Ground burial Ground singlet state

85 25 81 37

H Halobenzenes Halogenated xanthene dyes, photodegradation of Hazardous wastes detoxification of technology for detoxification of Heptachlor residues Herbicide(s) esters hydroylsis Orange sprays, composition of Hexachlorobenzene Hexachlorocyclopentadiene pyrolysis of

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

17 ..

35 57 49 100 141 141 101 7 7 74 7 113 113 115

155

INDEX

Hexane, immersion in 115 Hexane rinse 116 High-performance liquid chroma­ tography of rose bengal 40 High-temperature incineration 73 House fly 37 light-independent mortality of the .. 39 toxicity of rose bengal to 45 Hydrodechlorination 32 chemistry of 24 of DDE 27 of PCB 26 process flow diagram 31 Hydrogen bonding 147 8-Hydrogen mirex, pyrolysis of 114 10-Hydrogen mirex, pyrolysis of 114 Hydrolysis, relative rates of 4 I

Immersion in hexane 115 Immersion in methylene chloride 115 Incineration 14, 81,115 of captan 87 high-temperature 73 of Kepone 74 of maneb 87 of methyl parathion 87 of mirex 74 of organochlorine process wastes 74 of Temik 87 Initial degradation of maneb 86 of methyl parathion 86 of Temik 86 temperatures 86 Insecticidal activity of bound residues 139 Insecticide(s) 101 analysis 82 binding of C-labeled 138 extractibility of C-labeled 138 extractable residues of 132 residues bound 139 in soils, binding of 131 soil-bound 139 in soils, release of 131 thermal degradation of 81 Intermolecular interactions 147 Intersystem crossing 37 IR spectroscopy 64 Irradiation 14 14

14

Κ

Kepone incineration of -oxygen

63 74 66

L Lebaycid Liquid chromatography of rose bengal, high-performance

78 40

M

Malathion -argon combustion results with —oxygen reaction results of combustion tests on Maneb incineration of

77 60 127 65 129 82 87

Mass spectrometric (MS) analysis .... 57 Mercury derivatives chlorine-mercury interactions in 145 of chlorocarbons 146 of 2,6-dichlorophenol 150 2,6-dichlorophenoxides, NQR frequencies of 150 Metal-chlorine interaction 145 Methyl bromide-argon 60 bromide, detoxification of 66 parathion 82,84 incineration of 87 initial degradation of 86 Methylene chloride, immersion in 115 Microbial degradation 15 Microwave plasma characteristics 51 detoxification studies 51 detoxification system 56 process 49 system 52,53 expanded-scale 51, 55 utilization of 69 Mineralization 14 Minipit area 104 Minipit experiment Ill Mirex 82,84,86 incineration of 74 mass spectral data for 90 monohydrogen derivatives of 113 pyrolysis 112 residues 115 disposal 112 pyrolysis of 112 from shipping containers, removal of 116 thermal degradation of 92

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

156

Molten salt combustion 118 concept of 118 facilities 120 process concept 119 combustor, bench-scale 120,122 combustor, pilot-scale 123,124 disposal system, portable 127 test facility, feed system for the 128 waste disposal system, portable 128 Muffle furnace 84 results 85 treatments 84 Ν NASA/LEWIS Chemical Equilibrium Composition Computer Progra Nitric oxide formation Nitrofen NQR frequency (ies) of mercury 2,6-dichlorophenoxides splittings for 2,6-dichlorophenoxy compounds for 2,6-dichlorothiophenoxy compounds for trichloromethyl compounds ( nuclear quadrupole resonance spectroscopy ) variable-pressure Nuclear quadrupole resonance spectroscopy (NQR)

PCB 24 hydrodechlorination of 26 -oxygen 65 (polychlorinated biphenyl) 63 PCNB (pentachloronirrobenzene) .... 2 PCNB, photodecomposition products from 3 PCP 77 ( pentachlorophenol ) 1 Pentachloronirrobenzene (PCNB) .... 2 Pentachlorophenol (PCP) 1 irradiation of 2,18 Pentachlorophenyl mercurials 150 Performance liquid chromatography of rose bengal, high40 Pesticide(s) 57,127

9 20

, degradation temperatures 83 destruction of 118 detoxification of 49 disposal 81 150 research 73 incineration 82 mass spectral data for sulfur149 containing 88 nitrogen, oxidation of 97 149 photodecomposition, decontam­ 148 ination of 13 photodecomposition, disposal of .... 13 145 radiolabeled 131 147 technology for detoxification of 100 transformation of 13 145 Phénobarbital .141,142 Phenols, polychlorinated 145 Ο Phenylmercuric acetate 63 -oxygen 60,66 OCDD, photoreduction rates of ....... 6,9 Phloxin Β 38 Off-gas analysis for combustion of 37 simulated pesticide containers 126 Phosphorescence Olive oil 8,10 Photochemical Organochlorine breakdown 7 compounds 14 dechlorination 113 process wastes, incineration of 74 decomposition 8 wastes 74 reactions 15 Organophosphate compounds, reduction of aromatic halides 3 alkaline hydrolysis of 75 Photodecomposition Organophosphorous compounds 139 decontamination of pesticides 13 Orthocide-50 82 disposal of pesticides 13 Ozonation 77 products from PCNB 3 UV irradiation 77 Photodegradation of halogenated xanthene dyes 35 Ρ Photodegradation of the xanthene dyes, rate of 41 PAH (polyaromatic hydrocarbons) 66 15 Parathion 78,137 Photolysis of chlorobenzoic acids 19 C-ring labeled 131 of chlorobenzonitriles 19 residues, depletion curves of of chlorophenol methyl ethers 19 extractable 133 14

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

157

INDEX

Photolysis (continued) of chlorotoluenes 19 rate 21 Photooxidation, dye-sensitized 37 Photoreduction of 3,3'4,4'tetrachlorobiphenyl 4 Pilot-scale molten salt combustor .123,124 Pit disposal of excess hazardous materials 100 Plasma decomposition reactions, chemistry of 65 PMA-30, costs for 67 Pollutant gas analysis 85, 86 Polyaromatic dye-oxygen system 66 Polyaromatic hydrocarbons (PAH) .. 66 Polychlorinated biphenyl (PCB) 6 hydrocarbons, catalytic hydro dechlorination of 24 phenols 145 Poly ( vinyl chloride ) -compressed air manifold 105 Portable molten salt waste disposal system 127 Pyrolysis of 2,8-dihydrogen mirex 114 of 5,10-dihydrogen mirex 114 of hexachlorocyclopentadiene 115 of 8-hydrogen mirex 114 of 10-hydrogen mirex 114 mirex 112 of mirex residue 112 Q Quantum yield Quartz Raschig rings

16 63

R Radiolabeled pesticides 131 Recalcitrance 15 Reductive dechlorination 2,113 of polyhalogenated compounds 2 Release of insecticide residues in soils 131 Rhodamine Β 41 Rose bengal 35,38 absorbance of a 43 on Bacillus cereus, toxic effect of ... 47 food source 37 high-performance liquid chroma­ tography of 40,42 to house flies, toxicity of 45 on Stapholococcus areus, toxic effect of 46 visible absorbance spectrum of 40

S Sealed ampoule determinations 84 Sealed ampoule results 86 Sensitization 16 Settling ponds 81 Simulated pesticide containers, off-gas analysis for combustion of 126 Sodium carbonate .120,127 sulfate 120 trichlorophenate 8 Soil -bound insecticide residues 139 residues 139

Solvent extraction techniques 115 Soxhlet extractor 116 Spectral energy distribution of sunlight 4 Stapholococcus areus, toxic effect of rose bengal on 46 Sulfur-containing pesticides, combus­ tion products of 93 Sulfur-containing pesticides, mass spectral data for 88 Sunlight, spectral energy distribution 4

Τ TCDD 1,74 on grass 10 photochemical destruction of 7 photodecomposition rates of 9 photoreduction of 6 photoreduction rates of 6,9 residues 3 Temik 82 incineration of .-. 87 initial degradation of 86 Tetrachlorophenols 2 Thermal degradation of fungicides 81 insecticides 81 mirex 92 Threshold limit values (TLV) 127 Tissue dye level 37 T L V (threshold limit values) 127 Toxaphene 30,82,86 hydrodechlorination 30 mass spectral data for 90 Toxicity, dye-induced 37 Trichloromethyl compounds, NQR frequency splittings for 148 Trichloromethylmercurials 147

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

158 V Vacuum dropping funnel Vapam Variable-pressure NQR Venturi scrubber Volatilization without decomposition

57 77 147 118 131 85

Waste(s) (continued) disposal system, portable molten salt Wastewater treatment Water level gauge Wet oxidation costs

128 22 107 75 76

X W Waste(s) detoxication of disposal, costs of

13 22

Xanthene dyes 35,38 molecular structure of 39 photodegradation of halogenated .. 35 rate of photodegradation of the 41

In Disposal and Decontamination of Pesticides; Kennedy, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.