Clinical Toxicology Aspects of Controlled Release Pesticide

5 Clinical Toxicology Aspects of Controlled Release

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on December 30, 2015 | http://pubs.acs.org Publication Date: June 1, 1977 | doi: 10.1021/bk-1977-0053.ch005

Pesticide Formulations JOHN DOULL University of Kansas Medical Center, Kansas City, Kans. 66103

We are scheduled at t h i s point in the program to consider some of the clinical t o x i c o l o g i c aspects of the c o n t r o l l e d - r e l e a s e or microencapsulated p e s t i c i d e s . At the present t i m e , however, there are no reported human cases of poisoning w i t h microencapsulated p e s t i c i d e s , to my knowledge, and there i s relatively little acute and c h r o n i c toxicity data a v a i l a b l e f o r these agents in a n i m a l s . It i s e v i d e n t , t h e r e f o r e , that all we can do at t h i s point in time i s to speculate on how the use of these agents might a f f e c t the incidence and s e v e r i t y of p e s t i c i d e poisoning in t h i s country and to t r y to i d e n t i f y some of the problems that the emergency room p h y s i c i a n may have to deal w i t h in the event that these agents r e c e i v e widespread commercial usage. In looking back over the l a s t 40 years at the incidence and causes of p e s t i c i d e poisoning in t h i s c o u n t r y , i t seems to me that we have witnessed three more or l e s s distinct phases in the epidemiology of p e s t i c i d e poisoning and that we are now e n t e r i n g i n t o what may be a f o u r t h phase of t h i s problem. Pre-DDT Phase o f P e s t i c i d e P o i s o n i n g The f i r s t p h a s e , w h i c h I d e s i g n a t e a s t h e pre-DDT e r a , was c h a r a c t e r i z e d by t h e heavy m e t a l s a s t h e c h i e f c a u s e o f p e s t i c i d e p o i son i n g w i t h a r s e n i c a s t h e number o n e o f f e n d e r . Almost a l l o f t h e a g e n t s w h i c h were used a s p e s t i c i d e s d u r i n g t h i s p e r i o d were h i g h l y t o x i c and t h i s was t r u e f o r t h e b o t a n i c a l s , s u c h a s s t r y c h n i ne and η i c o t i n e , a s w e l l a s f o r t h e heavy m e t a l s , s u c h as a r s e n i c and l e a d . A l t h o u g h t h e u s e o f t h e s e a g e n t s was m o d e r a t e by t o d a y ' s s t a n d a r d s , t h e t o x i c i t y o f t h e s e a g e n t s made p e s t i c i d e p o i son i n g a s i g n i f i c a n t p r o b l e m i n p o i s o n control. Even i n t h o s e d a y s , h o w e v e r , i t was a r e l a t i v e l y m i n o r ρrobI em when compared w i t h o t h e r a g e n t s t h a t were r e s p o n s i b l e f o r p o i s o n ing c a s e s . I t has been e s t i m a t e d ( J j t h a t p e s t i c i d e s were r e s p o n s i b l e f o r between 5 and 101 o f t h e c a s e s

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In Controlled Release Pesticides; Scher, Herbert B.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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o f human p o i s o n i n g d u r i n g t h i s pre-DDT phase and t h a t r a t e was a b o u t 1 p e r m i l l i o n p o p u l a t i o n . DDT P h a s e o f

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The s e c o n d phase o f p e s t i c i d e p o i s o n i n g e p i d e m i o l o g y began w i t h t h e i n t r o d u c t i o n o f DDT i n t h e 1 9 ^ 0 s and t h e s u b s e q u e n t a d d i t i o n of other c h l o r i n a t e d hydrocarbon i n s e c t i c i d e s in the 1950's. D u r i n g t h i s p e r i o d t h e r e was a g r e a t i n c r e a s e i n t h e use o f p e s t i c i d e s i n t h i s c o u n t r y , b u t t h e r e was no c o r r e s p o n d i n g i n c r e a s e i n t h e number o f human c a s e s o f p e s t i c i d e p o i s o n i n g (2). In f a c t , t h e r e were d e c r e a s i n g t r e n d s i n b o t h t h e a b s o l u t e m o r t a l i t y and i n t h e p e r c e n t i n c i d e n c e o f p o i s o n i n g d u r i n g many p o r t i o n s o f what I r e f e r t o a s t h e DDT phase o f p e s t i c i d e poisoning epidemiology. Although the poison c o n t r o l s t a t i s t i c s f o r t h i s p e r i o d were e n c o u r a g i n g , t h e y w e r e n o t u n e x p e c t e d s i n c e we had a n t i c i p a t e d t h a t t h e r e p l a c e m e n t o f h i g h l y t o x i c p e s t i c i d e s l i k e a r s e n i c and s t r y c h n i n e w i t h a g e n t s l i k e DDT, which is comparatively n o n - t o x i c f o l l o w i n g acute i n g e s t i o n , w o u l d d e c r e a s e t h e emergency room p r o b l e m from p e s t i c i d e p o i s o n ing. I t was f u r t h e r a n t i c i p a t e d t h a t t h e m o r t a l i t y and m o r b i d i t y a s s o c i a t e d w i t h t h e o l d e r a g e n t s w o u l d d e c r e a s e a s t h e y were r e p l a c e d , and t h i s a l s o t u r n e d o u t t o be t r u e f o r b o t h a r s e n i c and s t r y c h n i n e ( 2 ) . These t r e n d s were somewhat c o u n t e r a c t e d , h o w e v e r , by t h e g r o w i n g p r o b l e m o f human p o i s o n i n g w i t h t h e o r g a n i c p h o s p h a t e i n s e c t i c i d e s and t o a much l e s s e r e x t e n t w i t h the carbamate i n s e c t i c i d e s . I t was a p p a r e n t d u r i n g t h e e a r l y I 9 6 0 s , f o r example, t h a t the o r g a n i c phosphate i n s e c t i c i d e s were c a u s i n g more o c c u p a t i o n a l p e s t i c i d e f a t a l i t i e s t h a n any o t h e r c l a s s o f a g r i c u l t u r a l c h e m i c a l s and t h a t i n heavy use a r e a s , l i k e F l o r i d a and C a l i f o r n i a , t h e o r g a n i c p h o s p h a t e i n s e c t i c i d e s were r e s p o n s i b l e f o r o v e r h a l f o f t h e s u i c i d e deaths. In one y e a r , f o r e x a m p l e , t h e y c a u s e d more d e a t h s i n Dade C o u n t y , F l o r i d a , t h a n a s p i r i n , w h i c h i s t r a d i t i o n a l l y o u r number one c a u s e o f p o i s o n i n g i n a l l a r e a s (J_).


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W i t h t h e b a n n i n g o f DDT i n t h e l a t e s i x t i e s and t h e s u b s e q u e n t removal o f o t h e r c h l o r i n a t e d h y d r o c a r b o n i n s e c t i c i d e s i n t h e e a r l y s e v e n t i e s , we have e n t e r e d i n t o what I c a l l t h e p o s t DDT o r t h i r d phase o f p e s t i c i d e e p i d e m i o l o g y . I t i s now a l m o s t 10 y e a r s s i n c e t h e a p p e a r a n c e o f t h e Mrak r e p o r t i n w h i c h t h e DDT ban was recommended. One o f t h e t h i n g s w h i c h was o f r e a l c o n c e r n t o s e v e r a l o f us who p a r t i c i p a t e d i n t h e p r e p a r a t i o n o f t h i s r e p o r t was t h e l i k e l i h o o d t h a t by e l i m i n a t i n g DDT, f a r m e r s and o t h e r u s e r s w o u l d be f o r c e d t o t u r n t o s u b s t i t u t e s w h i c h were f a r more t o x i c a c u t e l y and t h a t , i n e f f e c t , from t h e p o i s o n c o n t r o l v i e w p o i n t , we m i g h t have a s i t u a t i o n where t h e c u r e was w o r s e t h a n t h e d i s e a s e . Most emergency room p h y s i c i a n s


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t h a t t h i s i s e x a c t l y what has o c c u r r e d ( 3 ) . P e s t i c i d e s a r e v e r y much l i k e a n t i b i o t i c s i n t h a t t h e b e s t a g e n t o r d r u g o f c h o i c e i s u s u a l l y t h e one w h i c h e x h i b i t s a h i g h l y s e l e c t i v e t o x i c i t y to the i n v a d i n g p a r a s i t e or p e s t , yet i s r e l a t i v e l y n o n - t o x i c to the host or n o n - t a r g e t s p e c i e s . When t h e p h y s i c i a n i s d e n i e d t h e u s e o f a f i r s t - l i n e a n t i b i o t i c s u c h as pen i c i 11 i n b e c a u s e o f a l l e r g y o r some o t h e r r e a s o n and f o r c e d t o t u r n t o a s e c o n d - 1 i n e d r u g s u c h as v a n c o m y c i n o r even e r y t h r o m y c i n , he e x p e c t s t o e n c o u n t e r more t o x i c i t y p r o b l e m s . S i m i l a r l y , i n r e p l a c i n g f i r s t - l i n e p e s t i c i d e s l i k e DDT o r 2 , 4 - D , w h i c h c a u s e few a c u t e t o x i c i t y p r o b l e m s w i t h a g e n t s l i k e p a r a t h i o n o r p a r a q u a t , which p r e s e n t major treatment problems to t h e emergency room p h y s i c i a n , i t i s u n r e a l i s t i c t o e x p e c t t h a t we can e s c a p e t h e c o n s e q u e n c e s e i t h e r i n t e r m s o f t h e i n c i d e n c e o f p o i s o n i n g o r i n t h e s e v e r i t y o f t h e c a s e s w h i c h we see i n t h e emergency room. The most r e c e n t d a t a t h a t we have o b t a i n e d from t h e N a t i o n a l C l e a r i n g House f o r P o i s o n C o n t r o l C e n t e r s suggests t h a t i n s e c t i c i d e s a r e r e s p o n s i b l e f o r about h a l f o f a l l c a s e s o f p e s t i c i d e p o i s o n i n g , but t h e r e i s no breakdown o f t h i s d a t a i n t o t y p e o f i n s e c t i c i d e . In o u r own emergency room, i n s e c t i c i d e s a c c o u n t e d f o r a b o u t 7\% o f t h e p e s t i c i d e c o n t a c t s , but almost a l l o f the p e s t i c i d e p o i s o n i n g c a s e s w h i c h we t r e a t e d were o r g a n i c p h o s p h a t e i n t o x i c a t i o n s . We have had o n l y one c a s e o f c h l o r i n a t e d h y d r o c a r b o n i n s e c t i c i d e p o i son i n g w h i c h r e q u i r e d t r e a t m e n t i n t h e p a s t s e v e r a l m o n t h s , and t h a t was a 2 - y e a r - o l d g i r l who i n g e s t e d L i n d a n e .


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E l d o n Savage and h i s a s s o c i a t e s a t t h e Un i v e r s i t y o f Iowa, t h e Med i c a l Un i v e r s i t y o f S o u t h C a r o l i n a , and C o l o r a d o S t a t e Un i v e r s i t y have r e c e n t 1 y p u b l i s h e d t h e r e s u l t s o f t h e i r s u r v e y o f h o s p i t a l i z e d a c u t e p e s t i c i d e p o i son i n g i n t h e U n i t e d S t a t e s d u r i n g t h e y e a r s o f 1 9 7 1 , 1 9 7 2 , and 1973 W . In t h i s s t u d y , i n v e s t i g a t i v e teams w e r e s e n t o u t t o h o s p i t a l s i n b o t h h i g h and low p e s t i c i d e u s e a r e a s t o c o l l e c t d e m o g r a p h i c and h o s p i t a l r e c o r d i n f o r m a t i o n on b o t h o c c u p a t i o n a l and n o n - o c c u p a t i o n a l cases of p e s t i c i d e p o i s o n i n g . Organophosphate i n s e c t i c i d e s were t h e 1ead i n g c a u s e o f h o s p i t a l i z e d p e s t i c i d e p o i son i n g i n each of the three years surveyed f o r the o c c u p a t i o n a l exposure g r o u p , b u t i n t h e n o n - o c c u p a t i o n a l l y e x p o s e d g r o u p , w h i c h was m o s t l y c h i l d r e n u n d e r 5 , t h e o r g a n o p h o s p h a t e i n s e c t i c i d e s were r e s p o n s i b l e f o r l e s s t h a n 20% o f t h e p o i son i n g c a s e s . In i n t e r p r e t i n g t h i s t y p e o f d a t a , i t s h o u I d be k e p t i n mind t h a t p a t i e n t s who a r e h o s p i t a l i z e d f o r symptoms o f p e s t i c i d e p o i s o n i n g a r e more t h a n t w i c e a s l i k e l y t o d i e as t h o s e h o s p i t a l i z e d f o r symptoms o f o t h e r t y p e s o f p o i son i n g , and t h e d i f f e r e n c e is even more s t r i k i n g when one compares t h e outcome o f different c l a s s e s o f p e s t i c i d e s o r even d i f f e r e n t t y p e s o f i n s e c t i c i d e s . Prevention of

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a f f e c t p e s t i c i d e p o i s o n i n g i n t h e f u t u r e , we need t o c o n s i d e r some o f t h e c u r r e n t a p p r o a c h e s t o t h e p r o b l e m o f p r e v e n t i n g pesticide poisoning. One a p p r o a c h w o u l d be t o d e v e l o p new p e s t i c i d e s w h i c h e x h i b i t a much g r e a t e r s e l e c t i v e t o x i c i t y t h a n the c u r r e n t l y a v a i l a b l e p e s t i c i d e s . T h i s p r i n c i p l e has been used i n d e v e l o p i n g a n t i b i o t i c s s u c h as pen i c i 11 i n w h i c h k i 1 1 t h e p a r a s i t e by a mechan i sm wh i c h does n o t ex i s t i n t h e h o s t o r n o n - t a r g e t o r g a n i s m and t h e r e b y p r o v i d e s a t h e r a p e u t i c i n d e x o r s a f e t y m a r g i n o f o v e r 1000. I n s e c t g r o w t h r e g u l a t o r s and j u v e n i l e hormones a r e e x a m p l e s o f a g e n t s i n w h i c h an a t t e m p t i s made t o u t i l i z e a u n i q u e b i o l o g i c a l p r o p e r t y o f t h e i n s e c t t o p r o d u c e l e t h a l i t y and f o r w h i c h t h e r e may be no s t r i c t mammalian equivalent. Most p r e v i o u s a t t e m p t s t o d e v e l o p t h i s k i n d o f a b s o l u t e s e l e c t i v e t o x i c i t y i n p e s t i c i d e s have n o t been p r o d u c t i v e , b u t a t l e a s t one o f t h e s e j u v e n i l e h o r m o n e s , m e t h o p r e n e , a p p e a r s t o be r e m a r k a b l y s a f e and e n v i r o n m e n t a l l y h a r m l e s s ( 5 ) . A n o t h e r r e l a t e d a p p r o a c h i s t o u s e i n s e c t s e x pheromones and kairmones w i t h a t r a p p i n g system to reduce i n s e c t p o p u l a t i o n s . S i n c e i t t a k e s o n l y a few m o l e c u l e s o f t h e s e a g e n t s t o p r o d u c e t h e i r e f f e c t , i t does n o t a p p e a r l i k e l y t h a t t h e i r u s e w i l l create serious acute poisoning problems. I t has a l s o been p r o p o s e d t o use c h e m o s t e r i l a n t s , s u c h as t h e a l k y l a t i n g a g e n t s , o r g a n o t i n and f o r m a m i d i n e s , f o r i n s e c t c o n t r o l , b u t s i n c e some of these agents produce s e r i o u s t o x i c e f f e c t s , t h e r e are at l e a s t p o t e n t i a l poison c o n t r o l problems a s s o c i a t e d w i t h t h e i r use. There i s a l s o a g r e a t deal of c u r r e n t i n t e r e s t i n the use o f i n t e g r a t e d p e s t management p r a c t i c e s a s a p o s s i b l e s o l u t i o n t o t h e p e s t i c i d e p o i son i n g p r o b l e m and i n t h e d e v e l o p m e n t o f n a t u r a l l y o c c u r r i n g i n s e c t i c i d e s and new d e r i v a t i v e s o f o l d e r c l a s s e s of i n s e c t i c i d e s , such as the p y r e t h r o i d s (5). Although some o f t h e s e a p p r o a c h e s c o u l d have a s i g n i f i c a n t impact on t h e p r o b l e m o f p e s t i c i d e p o i son i n g as seen i n t h e emergency room, i t l o o k s l i k e i t i s g o i n g t o be q u i t e some t i m e b e f o r e t h e s e a p p r o a c h e s p r o d u c e any s i g n i f i c a n t change i n e i t h e r t h e i n c i d e n c e o r t y p e o f p o i son i n g t h a t we a r e e x p e r i e n c i n g t o d a y . T h e r e a r e , h o w e v e r , some o t h e r a p p r o a c h e s wh i c h c o u l d have a more immediate i m p a c t . One o f t h e s e w h i c h has been used abroad i s to r e s t r i c t the use o f h i g h l y t o x i c p e s t i c i d e s such a s p a r a t h i o n and m e t h y l p a r a t h i o n , w h i c h c a u s e more c a s e s o f o r g a n i c p h o s p h a t e i n s e c t i c i d e p o i son i n g t h a n a l l o f t h e r e s t o f the agents i n t h i s c l a s s . T h i s c o u l d be a c c o m p l i s h e d by s i m p l y b a n n i n g s e l e c t e d a g e n t s a s was done i n J a p a n o r by r e s t r i c t i n g the use o f such agents to 1icensed pest c o n t r o l o p e r a t o r s as p r o p o s e d by t h e EPA. E l i m i n a t i n g a l l o f t h e h i g h l y t o x i c a g e n t s , however, w i l l not e l i m i n a t e the problem of p e s t i c i d e p o i son i ng s i n c e p o i s o n i ng c a n a l s o o c c u r w i t h t h e l e s s t o x i c agents provided the exposure i s s u f f i c i e n t l y g r e a t . As s t a t e d by P a r a c e l s u s , t h e f a t h e r o f t o x i c o l o g y , " A l l s u b s t a n c e s a r e p o i s o n s , t h u s d o s a g e a l o n e d e t e r m i n e s p o i son i n g " ( 0 . As a f i r s t s t e p , h o w e v e r , we c a n s o l v e t h e p r o b l e m o f p e s t i c i d e



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CONTROLLED RELEASE

PESTICIDES

p o i s o n i n g i n t h e u s e r by i n s u r i n g t h a t a l l p e s t i c i d e s a r e f o r m u l a t e d i n s u c h a way t h a t i t becomes i m p o s s i b l e o r ν i r t u a l l y i m p o s s i b l e f o r t h e u s e r t o be e x p o s e d t o a t o x i c d o s e . We a r e a l r e a d y d o i n g t h i s t o some e x t e n t i n t h e d r u g a r e a by t h e use o f s a f e t y c l o s u r e s and l i m i t i n g t h e q u a n t i t y o f a g e n t i n e a c h c o n t a i n e r , and i t has made a d i f f e r e n c e i n t h e c a s e o f a s p i r i n poisoning. We a r e a l r e a d y moving i n t h i s d i r e c t i o n i n t h e p e s t i c i d e a r e a by u s i n g g r a n u l a r formulât i o n s , low volume s p r a y t e c h n i q u e s , and s y n e r g i z e r s wh i c h r e d u c e t h e amount o f p e s t i c i d e needed i n t h e formulât i o n . I t seems t o me t h a t m i c r o e n c a p s u l a t i o n o f p e s t i c i d e s o f f e r s an i n t e r e s t i n g and p o t e n t i a l method f o r a c h i e v i n g t h e same g o a l . As an emergency room phys i c i a n , I am a p p a l l e d when I w a l k i n t o my l o c a l h a r d w a r e s t o r e and f i n d t h a t I can p u r c h a s e b o t t l e s o f p e s t i c i d e s f o r m u l a t e d so t h a t a s i n g l e m o u t h f u l c o n s t i t u t e s a l e t h a l dose. t am n o t p a r t i c u l a r l y r e a s s u r e d by the f a c t t h a t each of these b o t t l e s c o n t a i n s a warning l a b e l d e s c r i b i n g the hazards a s s o c i a t e d w i t h exposure to the p e s t i c i d e , s i n c e most o f o u r p o i s o n i n g c a s e s o c c u r i n c h i l d r e n under f i v e who c a n ' t r e a d , o r a r e i n t e n d e d s u i c i d e s who u s e t h e l a b e l warn i n g a s a b a s i s f o r t h e i r s u i c i d e a t t e m p t . Changes i n o u r f o r m u l a t i o n p r a c t i c e s may n o t p r e v e n t p e s t i c i d e p o i s o n i n g i n t h e w o r k e r s engaged i n t h e m a n u f a c t u r e and f o r m u l a t i o n o f p e s t i c i d e s , and i t may n o t be p r a c t i c a l as a s o l u t i o n t o t h e problem o f o c c u p a t i o n a l p e s t i c i d e p o i s o n i n g i n a g r i c u l t u r e , but i t w o u l d c e r t a i n l y r e d u c e t h e p r o b l e m i n o u r emergency room and t h a t of o t h e r urban medical c e n t e r s . P o s s i b l e Tox i co1og i c P r o b l e m s w i t h M i c r o e n c a p s u l a t e d

Pesticides

I f we l o o k a t o u r p r e v i o u s e x p e r i e n c e w i t h g r a n u l a r f o r m u l a t i o n s o f p e s t i c i d e s , i t would appear t h a t the m i c r o e n c a p s u l a t e d p e s t i c i d e s s h o u l d be more e f f e c t i v e i n r e d u c i n g t h e i n c i d e n c e o f p e s t i c i d e p o i s o n i n g f o l l o w i n g dermal and i n h a l â t i o n e x p o s u r e than w i t h i n g e s t i o n . H o w e v e r , i n p a t i e n t s who i n g e s t g r a n u l a r f o r m u l a t i o n s o f p e s t i c i d e s , t h e symptoms g e n e r a l l y d e v e l o p more s l o w l y and a r e l e s s s e v e r e t h a n t h o s e seen i n p a t i e n t s who ingest p e s t i c i d e concentrates. G a s t r i c l a v a g e and a n t i d o t a l t r e a t m e n t a r e u s u a l l y more e f f i c a c i o u s i n s u c h c a s e s i n r e d u c i n g t h e amount o f p e s t i c i d e a b s o r b e d and i n p r e v e n t i n g t h e s u b s e q u e n t symptoms. Removal o f t h e g r a n u l a r m a t e r i a l by l a v a g e o r ernes i s sometimes p r e s e n t s p r o b l e m s b e c a u s e o f t h e t e n d e n c y o f t h e g r a n u l e s to form c o n c r e t ions i n the stomach. 11 i s a l s o p o s s i b l e t h a t the use o f the m i c r o e n c a p s u l a t e d p e s t i c i d e formul â t i o n i n an e n c l o s e d a r e a c o u l d , o v e r a l o n g per i o d o f t i m e , p r o d u c e an i n h a l â t i o n h a z a r d t o o c c u p a n t s o f t h e a r e a . I would a l s o be c o n c e r n e d a b o u t t h e p o s s i b i 1 i t y o f an i n d i v i d u a l ingesting the m i c r o e n c a p s u l a t e d p e s t i c i d e t o g e t h e r w i t h a s o l v e n t or emuls i f i e r w h i c h m i g h t f a c i l i t a t e t h e r e l e a s e o f t h e p e s t i c i d e . A l t h o u g h t h e m i c r o e n c a p s u l a t i o n p r o c e s s w o u l d n o t be e x p e c t e d



5.

DOULL

Clinical

Toxicology

Aspects

59

to i n t e r f e r e w i t h the a n t i d o t a l e f f i c a c y of the c u r r e n t l y a v a i l a b l e p e s t i c i d e a n t i d o t e s o r w i t h the usual t h e r a p e u t i c r e g i m e s used i n t h e management o f p o i s o n i n g , t h i s p o s s i b i 1 i t y s h o u l d be i n v e s t i g a t e d p r i o r t o t h e i r c o m m e r c i a l u s e . In a v e r y r e a l s e n s e , t h e emergency room phys i c i a n i s a t t h e end o f a l o n g d e v e l o p m e n t a l p r o c e s s , and by t h e t i m e he has to deal w i t h t h e p r o b l e m , t h e t o x i c o l o g y i s a c l o s e d book, t h e t o l e r a n c e s have been s e t , and t h e c h e m i s t s a r e a l l o f f l o o k i n g f o r a new a g e n t . I t seems t o me t h a t we need a more e n l i g h t e n e d a p p r o a c h t o t h e d e v e l o p m e n t o f new p e s t c o n t r o l measures w h i c h w o u l d r e c o g n i z e t h a t b o t h a c c i d e n t a l and i n t e n t i o n a l e x p o s u r e t o t h e a g e n t w i l l o c c u r and i n c l u d e s , t h e r e f o r e , a s p e c i f i c e f f o r t a l o n g t h e way t o f i g u r i n g o u t how s u c h p a t i e n t s s h o u l d be h a n d l e d . i t i s a l o t e a s i e r t o t r e a t a p o i s o n i n g when t h e management i s p r e p l a n n e d and t e s t e d t h a n when i t i s d i c t a t e d by a c r i s i s s î t u a t i o n i n v o l ν i n g an unknown a g e n t . I thank you f o r învi t i n g me t o p a r t i c i p a t e a t t h i s e a r l y s t a g e .

Literature Cited 1.

Murphy, S. D., "Pesticides" In: Toxicology, the Basic Science of Poisons, Eds. L. J. Casarett and J. Doull, Macmillan Publishing Co., New York, Ν. Y . , 1975. 2. Hayes, W. J., "Recognized and Possible Effects of Pesticides in Man" In: Toxicology of Pesticides, Ed. W. J. Hayes, Williams and Wilkins, Baltimore, Md., 1975. 3. Doull, J., "The Treatment of Insecticide Poisoning" In: Insecticide Biochemistry and Physiology, Ed. C. F. Wilkinson, Plenum Publishing Co., New York, Ν. Y . , 1976. 4. Savage, Ε. P., "A Study of Hospitalized Acute Pesticide Poisoning in the United States", 1971 to 1973" EPA Contract 68-02-1271 and 68-01-3138, 1975. 5. Woods, J. S., Ed., Conference on Human Health Effects of New Approaches to Insect Pest Control, Environmental Health Perspectives (1976) 14: 1-193.


Clinical Toxicology Aspects of Controlled Release Pesticide

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