Safety Evaluation of Pesticides in Ground Water - ACS Publications

24 Safety Evaluation of Pesticides in Ground Water D. D. Sumner and J. T. Stevens

Downloaded by UNIV OF ROCHESTER on June 12, 2018 | https://pubs.acs.org Publication Date: July 17, 1986 | doi: 10.1021/bk-1986-0315.ch024

Agricultural Division, CIBA-GEIGY Corporation, Greensboro, NC 27419

As tbe sensitivity of analytical methods increases, more instances of pesticide detection in groundwater will occur. In order to avoid a series of crisis situations, it is necessary that standardized procedures for the identification of safe levels of chemicals in groundwater be established. The same basic principles used to establish safe levels in food, can be used to establish safe levels in groundwater. Some methods used to establish acceptable levels in groundwater are discussed. The setting of acceptable levels at zero or limits of detection, should be avoided since practical considerations preclude these approaches. The p r e s e n c e o f c h e m i c a l s i n groundwater has become a prominent and e m o t i o n a l i s s u e . I n t h e past few y e a r s , few i s s u e s have produced t h e e m o t i o n a l r e s p o n s e s t h a t accompany groundwater contamination. T h i s r e s p o n s e seems i n t e n s i f i e d when t h e c h e m i c a l which c o n t a m i n a t e s the water i s a p e s t i c i d e [ 1 ] . Many s c i e n t i f i c and r e g u l a t o r y b o d i e s have c o n s i d e r e d t h e q u e s t i o n o f groundwater and c h e m i c a l s , and an even g r e a t e r number are c u r r e n t l y c o n s i d e r i n g t h i s i s s u e . F e d e r a l a g e n c i e s under s e v e r a l s t a t u e s [2, 3, 4, 5] and s e v e r a l s t a t e r e g u l a t o r y o r l e g i s l a t i v e b o d i e s [6, 7, 8, 9] a r e a c t i v e l y i n v e s t i g a t i n g groundwater q u a l i t y and s t a n d a r d s . I n d u s t r y as w e l l as e n v i r o n m e n t a l groups are a c t i v e i n d i r e c t i n g a t t e n t i o n t o groundwater. A l t h o u g h t h e r e i s u n i f o r m i t y i n t h e i n t e r e s t i n groundwater, c o n s i d e r a b l e d i f f e r e n c e s e x i s t among t h e r e s p e c t i v e groups i n t h e i r approaches t o s e t t i n g a c c e p t a b l e l i m i t s f o r c h e m i c a l s i n groundwater. Some groups want no a c c e p t a b l e l e v e l s f o r any c h e m i c a l i n groundwater, w h i l e o t h e r groups want t o s e t s t a n d a r d s which ensure s a f e t y o f t h e water [6, 7, 10, 1 1 ] . The l a t t e r a r e t y p i f i e d by t h e Maximum Contaminant L e v e l s (MCL's) s e t by the EPA O f f i c e o f D r i n k i n g Water (ODW), which a r e l e g a l l y e n f o r c e a b l e standards. 0097-6156/ 86/ 0315-0436506.00/ 0 © 1986 American Chemical Society

Garner et al.; Evaluation of Pesticides in Ground Water ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

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As d i s c u s s e d w i t h i n t h i s symposium, i t i s not p o s s i b l e to keep a l l c h e m i c a l s out o f groundwater. As l i m i t s o f d e t e c t i o n are reduced more c h e m i c a l s w i l l be d e t e c t e d . C l e a r l y t h e r e are many d i f f e r e n t c h e m i c a l s i n our p o t a b l e water. Some are i n t e n t i o n a l l y i n t r o d u c e d , such as c h l o r i n e or f l u o r i d e s a l t s ; some are n a t u r a l p r o d u c t s ; some are u n i n t e n t i o n a l l y p r e s e n t , such as pathogens, i n d u s t r i a l c h e m i c a l s , p h a r m a c e u t i c a l s , and p e s t i c i d e s ; and some are s y n t h e s i z e d i n s i t u , such as c h l o r o f o r m . A l t h o u g h c l e a r documentation o f a d v e r s e e f f e c t s i s not common, e p i d e m i o l o g i c a l i m p l i c a t i o n s o f water q u a l i t y e f f e c t s have been r e p o r t e d [ 1 2 ] . The p r e s e n t paper w i l l address q u e s t i o n s c o n c e r n i n g the s a f e t y of p e s t i c i d e s i n groundwater from the p e r s p e c t i v e of human h e a l t h . S e v e r a l f a c t o r s c o n t r i b u t e to the a t t e n t i o n c u r r e n t l y g i v e n t o p e s t i c i d e s i n groundwater. One of the most important f a c t o r s i s the p r o g r e s s which has been made i n a n a l y t i c a l methodology. In the 'oO's, methods were a v a i l a b l e to measure m a t e r i a l s i n the p a r t s per m i l l i o n (ppm) range. In the '80's, i t i s not uncommon to have methods which can d e t e c t some m a t e r i a l s i n the p a r t s per t r i l l i o n ( p p t ) range. T h i s c o n s t i t u t e s a one m i l l i o n - f o l d i n c r e a s e i n sensitivity. An a d d i t i o n a l f a c t o r c o n t r i b u t i n g to the p r o l i f e r a t i o n o f r e p o r t s on p e s t i c i d e c o n t a m i n a t i o n o f groundwater i s ease o f p e s t i c i d e analysis. P e s t i c i d e s are a p r e d e f i n e d a n a l y t i c a l t a r g e t . Federal r e g u l a t i o n s [2] r e q u i r e the development o f d e f i n e d a n a l y t i c a l methods which make i d e n t i f i c a t i o n e a s i e r than many o t h e r m a t e r i a l s , e s p e c i a l l y natural products. F i n a l l y , the c u r r e n t i n t e r e s t i n p e s t i c i d e s i n groundwater p r o b a b l y f o c u s e s e f f o r t s which may otherwise have been d i r e c t e d to o t h e r c h e m i c a l s . The r e a c t i o n to the p r e s e n c e o f p e s t i c i d e s i n groundwater i s a l s o i n f l u e n c e d by a m u l t i p l i c i t y o f f a c t o r s . In a d d i t i o n to the p o t e n t i a l t o x i c i t y o f the m a t e r i a l s or t h e i r p o t e n t i a l e n v i r o n m e n t a l e f f e c t s , e m o t i o n a l f a c t o r s seem to c o n t r i b u t e to the negative response. F o r example, s i m a z i n e i s i n v o l v e d i n a groundwater i s s u e . Simazine has an L D o f a p p r o x i m a t e l y 5,000 mg/kg [ 1 3 ] . This i s less a c u t e l y t o x i c than t a b l e s a l t , which has an L D ^ Q o f a p p r o x i m a t e l y 4,000 mg/kg [14], Simazine can be f e d i n the d i e t s o f r o d e n t s f o r t h e i r l i f e t i m e at 3,000 ppm w i t h o u t any remarkable e f f e c t [15] or a d m i n i s t e r e d d a i l y at 215 mg/kg/day i n an N a t i o n a l Cancer I n s t i t u t e (NCI) b i o a s s a y w i t h o u t o n c o g e n i c e f f e c t [ 1 6 ] . b U

Simazine has r e c e i v e d c o n s i d e r a b l e n o t o r i e t y based upon the f i n d i n g o f l e v e l s e q u a l t o or l e s s than 3.5 ppb i n s i x out o f 217 w e l l s e v a l u a t e d i n a study i n C a l i f o r n i a [ 1 7 ] . These s i x w e l l s are suspected of being point source contaminations [18]. Based upon the t o x i c i t y d a t a and i t s use i n a l g a e and weed c o n t r o l i n ponds, s i m a z i n e has a p o t a b l e water t o l e r a n c e o f 10 ppb. I t has a Suggested No Adverse Response L e v e l [SNARL] e s t a b l i s h e d by the N a t i o n a l Academy o f S c i e n c e s o f 1,500 ppb. However, because o f the


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n o t o r i e t y a s s o c i a t e d with the f i n d i n g s i n the s i x w e l l s , there i s a move t o r e s t r i c t the product from use on sand and loamy sand s o i l s [19].


G i v e n t h e e m o t i o n a l i s m aroused by p e s t i c i d e s found i n groundwater, i t i s d i f f i c u l t t o propose an a c c e p t a b l e s o l u t i o n t o t h e dilemma. Furthermore, c o n s i d e r i n g the c o m p l e x i t i e s o f the issues i n v o l v e d , i t would be presumptuous t o t r y t o a d d r e s s a l l i s s u e s and p o s s i b l e r e s o l u t i o n s i n a s i n g l e paper. I n s t e a d our d i s c u s s i o n w i l l focus on some o f t h e approaches t h a t have been t a k e n o r a r e b e i n g taken to c o n s i d e r the v i t a l q u e s t i o n o f e s t a b l i s h i n g s a f e / a c c e p t a b l e l i m i t s o f p e s t i c i d e l e v e l s i n groundwater. The importance o f s e t t i n g a c c e p t a b l e l i m i t s f o r p e s t i c i d e s i n groundwater cannot be u n d e r e s t i m a t e d . W i t h t h e s e n s i t i v i t y o f c u r r e n t methods and t h e e x p a n s i o n o f m o n i t o r i n g e f f o r t s , i n s t a n c e s o f p e s t i c i d e d e t e c t i o n i n water a r e i n e v i t a b l e . Each o f these i n s t a n c e s w i l l p r e c i p i t a t e a c r i s i s i f t h e a n a l y t i c a l v a l u e s cannot be p l a c e d i n p e r s p e c t i v e w i t h r e g a r d t o r e l a t i v e h a z a r d . In t h e absence o f a c c e p t a b l e l i m i t s , i n s t a n c e s o f d e t e c t i o n c o u l d be e x p e c t e d t o r e s u l t i n o v e r r e a c t i o n t o t r i v i a l e v e n t s . I f false alarms o c c u r f r e q u e n t l y , t h e consumer may become complacent and hazardous s i t u a t i o n s c o u l d be i g n o r e d . The e s t a b l i s h m e n t o f a c c e p t a b l e l i m i t s i s c r i t i c a l from a l e g a l / p u b l i c r e l a t i o n s p e r s p e c t i v e as w e l l as from a s a f e t y p e r s p e c t i v e . S e t t i n g a c c e p t a b l e l i m i t s f o r c h e m i c a l s i n water w i l l reduce the number o f c r i s i s s i t u a t i o n s and a f f o r d o p p o r t u n i t i e s f o r o r d e r l y d e c i s i o n s c o n c e r n i n g water q u a l i t y and s a f e t y . Hence, i t i s a p p r o p r i a t e t o g i v e c o n s i d e r a t i o n t o some o f t h e contemporary approaches f o r t h e e s t a b l i s h m e n t o f these s a f e l i m i t s . The N a t i o n a l Academy o f S c i e n c e s (NAS) a d d r e s s e d t h e groundwater i s s u e i n r e s p o n s e t o t h e Safe D r i n k i n g Water A c t o f 1974 [ 4 ] . The NAS e x a m i n a t i o n [20] d e a l t w i t h a broad spectrum o f p o s s i b l e m a t e r i a l s i n c l u d i n g m i c r o b i a l , i n o r g a n i c , o r g a n i c , and r a d i o n u c l e o t i d e contaminants; s e v e r a l p e s t i c i d e s i n c l u d e d . The NAS used t o x i c o l o g y d a t a t o e s t a b l i s h an A c c e p t a b l e D a i l y Intake (ADl) f o r each o f t h e m a t e r i a l s c o n s i d e r e d . The ADI was e s t a b l i s h e d u s i n g t h e N o - O b s e r v e d - E f f e c t l e v e l (NOEL) from a n i m a l s t u d i e s and a s e r i e s o f S a f e t y F a c t o r s r a n g i n g from 10 t o 1,000 depending upon t h e d u r a t i o n o f animal t o x i c i t y s t u d i e s and t h e nature o f the t o x i c e f f e c t s . F o r oncogens t h e NAS recommended c o n s i d e r a t i o n o f t h e M u l t i - S t a g e model o f c a r c i n o g e n e s i s . I f the d a t a a v a i l a b l e were n o t s u f f i c i e n t f o r use o f t h e M u l t i - S t a g e Model, then t h e One-Hit Model was s u g g e s t e d . The NAS used t h e ADI t o e s t a b l i s h an a c c e p t a b l e maximum l i m i t d e s i g n a t e d t h e Suggested No Adverse Response L e v e l (SNARL). The NAS assumed 20% o f t h e ADI was a v a i l a b l e f o r water c o n t r i b u t i o n


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( r e s e r v i n g 80% f o r o t h e r s o u r c e s ) . C a l c u l a t i o n o f the SNARL based upon a 70 kg person d r i n k i n g two l i t e r s per day.


NAS

SNARL = NOEL (mg/kg/day)

SF X 20%

2L/day X 70

was

kg

The p r o c e d u r e s u t i l i z e d by the NAS i n e s t a b l i s h i n g S a f e t y F a c t o r s and e v a l u a t i n g the animal d a t a are e s s e n t i a l l y e q u i v a l e n t to the c u r r e n t s t a n d a r d s [ 2 1 ] , The suggested use o f the M u l t i - S t a g e Model i s f u r t h e r c o m p a t i b l e w i t h l a t e r recommendations [22, 23]. The NAS l i m i t e d i t s c o n s i d e r a t i o n o n l y t o p u b l i s h e d d a t a , r e a s o n i n g the p u b l i s h e d d a t a has undergone peer r e v i e w . However, i n the case o f p e s t i c i d e s most o f the d a t a r e s i d e s i n c o r p o r a t e and EPA f i l e s and not i n the l i t e r a t u r e . The r e s t r i c t e d database thus i s a weakness and a l i m i t i n g f a c t o r a s s o c i a t e d w i t h the NAS approach. Several s o u r c e s [24, 25] have recommended t h a t a l l a v a i l a b l e d a t a be used i n s a f e t y e v a l u a t i o n . A l t h o u g h not a l l o f these d a t a w i l l have been p u b l i s h e d , the d a t a w i l l have undergone r e g u l a t o r y r e v i e w . F o r t u n a t e l y , o t h e r groups have c o n s i d e r e d an expanded d a t a b a s e . The N a t i o n a l A g r i c u l t u r a l Chemical A s s o c i a t i o n (NACA) e s t a b l i s h e d a committee to l o o k i n t o groundwater i s s u e s i n 1983. That committee made recommendations s i m i l a r t o but not i d e n t i c a l w i t h the NAS procedures. The NACA committee recommended u s i n g the e x i s i t i n g database w i t h i n EPA. The database r e q u i r e d f o r p e s t i c i d e s i s v e r y e x t e n s i v e ( T a b l e I ) and p r o v i d e s c o n s i d e r a b l e i n f o r m a t i o n upon which to d e v e l o p a s a f e t y e v a l u a t i o n . T a b l e I.

A Partial List

o f P e s t i c i d e Data Requirements

Standard Acute S t u d i e s 90-Day S t u d i e s i n Rats 1-Year S t u d i e s i n Dogs Teratology i n 2 Species L i f e t i m e Feeding Studies i n 2 Species M u l t i g e n e r a t i o n Reproduction Studies Metabolism i n P l a n t s , A n i m a l s , and S o i l Residue D e t e r m i n a t i o n s i n Food and Nonfood Methods t o Determine Residues

K i n e t i c s of Environmental Degradation M o b i l i t y i n the Environment P o t e n t i a l for Bioaccumulation Avian Acute T o x i c i t y Avian Reproductive E f f e c t s A v i a n Acute T o x i c i t y A q u a t i c C h r o n i c and Reproduction E f f e c t s Marine E f f e c t s Aquatic Vegetation T o x i c i t y on Earthworms, Bees, and Other B e n e f i c i a l Invertebrates

In f a c t , p e s t i c i d e s are some o f the most t h o r o u g h l y s t u d i e d c h e m i c a l s i n our environment. T y p i c a l d a t a needed f o r a food t o l e r a n c e i n c l u d e : a c u t e , s u b c h r o n i c , r e p r o d u c t i o n , and c h r o n i c , as w e l l as o n c o g e n i c i t y , m u t a g e n i c i t y , and e n v i r o n m e n t a l s t u d i e s [26]. P e s t i c i d e s are unique i n t h a t not o n l y s t u d i e s from the mammalian h e a l t h p e r s p e c t i v e are completed but a l s o e n v i r o n m e n t a l i n v e s t i g a t i o n s [27, 28].


440



I t was the o p i n i o n o f the NACA committee [10] t h a t the e x i s t i n g ADI e s t a b l i s h e d f o r a l l p r o d u c t s w i t h food t o l e r a n c e s i s adequate t o e s t a b l i s h maximum s a f e l e v e l s i n groundwater. The ADI e s t a b l i s h e d by EPA i s based upon the database i n the Agency. The development o f an ADI i s e s s e n t i a l l y the same i n the NAS proced u r e s , the EPA Food T o l e r a n c e p r o c e d u r e s , and the NACA p r o p o s a l f o r groundwater. An ADI i s determined by d i v i d i n g the NOEL i n the most s e n s i t i v e s p e c i e s by a s u i t a b l e S a f e t y F a c t o r ( S F ) . S a f e t y F a c t o r s f o r s u b c h r o n i c or r e p e a t a d m i n i s t r a t i o n are u s u a l l y 1,000; f o r c h r o n i c or l i f e t i m e s t u d i e s , 100 i s used. S p e c i e s c o n v e r s i o n s can be based upon mg/kg, ppm i n the food, or body s u r f a c e a r e a c o n v e r s i o n [ 2 9 ] . C u r r e n t l y , non-oncogenic e f f e c t s are c o n s i d e r e d on an mg/kg b a s i s w i t h o u t attempts to c o r r e c t f o r s p e c i e s d i f f e r e n c e s . R i s k assessment p r o c e d u r e s f o r oncogenic r i s k employed by the EPA are based upon s u r f a c e a r e a e x t r a p o l a t i o n s i n an attempt to r e l a t e to man [ 3 0 ] . The e s t a b l i s h m e n t o f a maximum a c c e p t a b l e c o n c e n t r a t i o n o f any c h e m i c a l i n p o t a b l e water s h o u l d not be done i n i s o l a t i o n , but s h o u l d c o n s i d e r a l l s o u r c e s o f exposure. Intake o f p e s t i c i d e s can r e s u l t from worker exposure, i n g e s t i o n , and water e x p o s u r e . Workr e l a t e d exposure i s time and space l i m i t e d and i s r e s t r i c t e d t o l i m i t e d p o p u l a t i o n s which are e v a l u a t e d i n s e p a r a t e s t u d i e s and are not as a l l encompassing as food and water exposure. I n g e s t i o n o f food i s examined u s i n g T h e o r e t i c a l Maximum R e s i d u e C o n t r i b u t i o n (TMRC) approach. The TMRC i s based upon t o l e r a n c e s e s t a b l i s h e d f o r raw a g r i c u l t u r a l commodities. I t assumes a l l c r o p s are t r e a t e d and t h a t a l l r e s i d u e s o c c u r at the maximum l e v e l seen i n use s i t u a t i o n s . T o l e r a n c e s are u s u a l l y s e t at the l i m i t o f a n a l y t i c a l d e t e c t i o n when r e s i d u e s are not e x p e c t e d to o c c u r . For i n s t a n c e , f r u i t t r e e s s p r a y e d d u r i n g dormancy w i t h a p r o d u c t t h a t degrades b e f o r e f r u i t are formed; hence such t o l e r a n c e s i n the f r u i t are m e a n i n g l e s s . T h e r e f o r e , TMRC g r e a t l y e x a g g e r a t e s p e s t i c i d e i n t a k e . Market basket surveys have shown a c t u a l r e s i d u e s to be l e s s than the expected TMRC v a l u e s . F o r most p r o d u c t s the d i e t a r y c o n t r i b u t i o n s are l e s s than 10% o f the TMRC. T y p i c a l v a l u e s from the market basket survey are shown i n T a b l e I I [31, 3 2 ] . S i n c e the TMRC f o r food r e s i d u e s so v a s t l y exaggerated p e s t i c i d e i n t a k e , the NACA committee d i d not sponsor t h i s approach i n the s e t t i n g o f p e s t i c i d e l i m i t s i n water. On the o t h e r hand, they d i d not want t o i g n o r e the d i e t a r y c o n t r i b u t i o n t o p e s t i c i d e i n t a k e . The d i e t a r y c o n t r i b u t i o n was e v i d e n t l y r e s o l v e d by a d o p t i n g a d i f f e r e n t model f o r consumption. The NACA committee recommended use o f a 10 kg c h i l d d r i n k i n g one l i t e r o f water per day; the TMRC was i g n o r e d . T h i s model p r o v i d e s an a d d i t i o n a l 3.5


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TABLE I I


R e l a t i o n s h i p o f " T h e o r e t i c a l Intake" to "Actual Intake" o f Seven P e s t i c i d e s i n t h e D i e t *

Acceptable Daily Intake mg/day

Relationship of ADI t o Actual Intake

Theoretical P e s t i c i d e Intake mg/day

Relationship Actual of A c t u a l I n Intake take t o T h e o r e mg/day^ t i c a l Intake

DDT

6.79

0.029

230:1

0.300

10:1

dicofol

4.45

0.006

740:1

1.500

250:1

dieldrin

0.23

0.006

40:1

0.006

lindane

9.21

0.003

>1,000:1

0.750

250:1

0.008

>1,000:1

1.20

150:1

>1,000:1

0.300

malathion

12.56

parathion

1:18

300:1 20:1

C a l c u l a t e d from USA t o l e r a n c e and 9 t h d e c i l e consumption f i g u r e s minimum f i g u r e s s i n c e s m a l l consumption commodities are e x c l u d e d . USA t o l e r a n c e s used f o r c a l c u l a t i o n s were those i n e f f e c t d u r i n g 1964-1970. T o l e r a n c e s f o r DDT and d i e l d r i n on c e r t a i n commodities were reduced d u r i n g 1968-69; however, the h i g h e r t o l e r a n c e s were used i n t h e c a l c u l a t i o n s . ^ D i e t a r y Intake o f P e s t i c i d e C h e m i c a l s i n t h e U n i t e d S t a t e s ( I I I ) , R. E . Duggan and P. E . C o r n e l i u s s e n , P e s t i c i d e M o n i t o r ing J o u r n a l , _5, No. 4, March, 1972. 3

P e s t i c i d e R e s i d u e s i n Foods - Report o f t h e 1971 J o i n t FAO/WHO M e e t i n g , FAO A g r i c u l t u r a l S t u d i e s , Number 88. Based on a 60 kilogram i n d i v i d u a l .

*From FAO/WHO Food Standards Program, 1974.

[31]

S a f e t y F a c t o r over the 70 kg p e r s o n d r i n k i n g two l i t e r s . The o r i g i n a l S a f e t y F a c t o r d e t e r m i n a t i o n s by t h e NAS [33] i n c l u d e d c o n s i d e r a t i o n o f s u s c e p t i b l e p o p u l a t i o n subgroups so c h i l d r e n i n some r e s p e c t s had a l r e a d y been c o n s i d e r e d . The NACA committee suggested t h e term H e a l t h A d v i s o r y (HA) f o r the maximum a c c e p t a b l e pesticide levels.

HACA HA - NOEL (mg/kg/day)

SF

A

l L / d a y X 10 kg


442


L i k e w i s e , ODW a t EPA had used the 10 kg c h i l d as a model i n s e t t i n g MCL's. By t h e i r a d o p t i o n o f t h e model u s i n g a 10 kg p e r s o n d r i n k ing one l i t e r p e r day [ 3 4 ] , i t can be deduced t h a t the NACA committee compensated f o r d i e t a r y c o n t r i b u t i o n by a d o p t i n g 28.5% o f t h e ADI f o r water, which a f f o r d s a c o n s i d e r a b l e margin o f s a f e t y c o n s i d e r i n g t h e market b a s k e t survey d a t a ( T a b l e 2 ) .


F o r o n c o g e n i c m a t e r i a l s the NACA committee recommended a c a l c u l a t e d r i s k o f one i n a m i l l i o n u s i n g t h e M u l t i - S t a g e model. The NACA committee f u r t h e r i n d i c a t e d t h a t H e a l t h A d v i s o r i e s a r e not i n t e n d e d to encourage p r a c t i c e s which w i l l r e s u l t i n h e a l t h a d v i s o r y l e v e l s [10]. R e c e n t l y t h e S t a t e o f W i s c o n s i n has adopted groundwater l e g i s l a t i o n which i n t r o d u c e s s e v e r a l i n t e r e s t i n g a s p e c t s . The W i s c o n s i n b i l l [8] e s t a b l i s h e s a b a s i s f o r n u m e r i c a l s t a n d a r d s based upon t o x i c o l ogy d a t a and a v o i d s " l i m i t s o f d e t e c t i o n . " R e g u l a t i o n based upon l i m i t s o f d e t e c t i o n may seem a t t r a c t i v e on the s u r f a c e , but t o x i c o l o g y i s independent o f a n a l y t i c a l t e c h n i q u e . At b e s t , " l i m i t o f d e t e c t i o n " p r o v i d e s l i t t l e r e l e v a n c e t o b i o l o g y ; at worst, i t rewards s l o p p y o r i n e p t a n a l y t i c a l development. The W i s c o n s i n b i l l r e c o g n i z e s the p o s s i b i l i t y o f f u t u r e d e v e l o p ments. I t r e c o g n i z e s t h e e x i s t e n c e o f p r e s e n t and f u t u r e f e d e r a l s t a n d a r d s i n c l u d i n g t h e E P A - e s t a b l i s h e d ADI v a l u e s . I t incorpor a t e s p r o v i s i o n s t o a c c e p t t e c h n i c a l advancements i n t o x i c o l o g y o r a n a l y t i c a l chemistry. The W i s c o n s i n b i l l i n t r o d u c e s an i n t e r e s t i n g concept c a l l e d t h e P r e v e n t i v e A c t i o n L i m i t (PAL). C o n c e p t u a l l y , t h i s c a n be e n v i s i o n e d as some major p o r t i o n o f the enforcement s t a n d a r d which c o u l d t r i g g e r i n v e s t i g a t i o n s i n t o s o u r c e s f o r groundwater c o n t a m i n a t i o n , i . e . , improper d i s p o s a l , p o i n t s o u r c e s , e t c . In p r a c t i c e i t i s an a d d i t i o n a l s a f e t y f a c t o r s i n c e t h e s t a t e r e g u l a t o r y r e s p o n s e i s n e a r l y the same whether a s t a n d a r d o r PAL i s exceeded. Recent r u l e m a k i n g i n New York has a l s o i n t r o d u c e d another concept [35]. The s t a t e has proposed t h a t f o r o r d i n a r y t o x i c i t y , t h e water s t a n d a r d s h a l l u t i l i z e c a l c u l a t i o n s based on a 10 kg c h i l d d r i n k i n g one l i t e r o f w a t e r . But f o r o n c o g e n i c i t y , a 60 kg p e r s o n d r i n k i n g two l i t e r s p e r day i s used. This i s l o g i c a l since oncogenicity s t u d i e s a r e based upon l i f e t i m e f e e d i n g s t u d i e s , thus c o v e r i n g t h e adult period. In a d d i t i o n , New York has p r o v i d e d a c l a s s i f i c a t i o n mechanism f o r groundwater so t h a t a q u i f e r s which a r e u n u s a b l e f o r n a t u r a l r e a s o n s w i l l n o t need as much p r o t e c t i o n as those which a r e u s e f u l . I t would, o f c o u r s e , be a s u b s t a n t i a l o m i s s i o n not t o mention EPA. C o n s i d e r a b l e a c t i v i t y i s i n p r o g r e s s , b u t t h i s has been p r e v i o u s l y d i s c u s s e d by Dr. S t a r a [36] w i t h i n t h i s symposium.


24.

SUMNER AND STEVENS

Safety Evaluation

of

Pesticides

443


A l t h o u g h i t would be presumptuous t o attempt t o d e f i n e a program t o r e s o l v e a l l q u e s t i o n s c o n c e r n i n g p e s t i c i d e s i n groundwater, i t i s p o s s i b l e t o recommend c e r t a i n elements which would appear t o be n e c e s s a r y f a c t o r s i n any r e s o l u t i o n . Some o f the most important a s p e c t s seem t o be: •

I n o r d e r t o a v o i d a c r i s i s e v e r y time a p e s t i c i d e i s d e t e c t e d , maximum a c c e p t a b l e l e v e l s s h o u l d be s e t b e f o r e samples a r e analyzed.

•

S a f e t y e v a l u a t i o n s s h o u l d i n c l u d e use o f the e n t i r e d a t a b a s e . Data i n t h e p u b l i s h e d l i t e r a t u r e and t h a t i n EPA f i l e s s h o u l d a l l be c o n s i d e r e d . To do o t h e r w i s e , s h o r t changes the p u b l i c and t h e i n d u s t r y .

•

A c c e p t a b l e l e v e l s s h o u l d be based wherever p o s s i b l e on t o x i c o l o g y d a t a , n o t l i m i t s o f d e t e c t i o n . T o x i c i t y i s independent of a n a l y t i c a l t e c h n i q u e .

•

Acceptable l e v e l s should consider environmental mammalian h e a l t h e f f e c t s .

•

More p u b l i c e d u c a t i o n t o p r o v i d e i n f o r m a t i o n c o n c e r n i n g t h e b a s i s f o r s e t t i n g containment l e v e l s and t o c o u n t e r a c t "emotionalism".

as w e l l as

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Knudson, T., Groundwater Chemicals Cancer Linked, Pes Moines, Sunday Register, June 16, 1985. Federal Insecticide Fungicides, Rodenticide Act Toxic Substances Control Act. Clean Water Act. Resources Conservation and Recovery Act. Kim, Ν. K. and D. W. Stone, "Organic Chemicals and Drinking Water". New York State Department of Health, April 1981. State of Florida Statutes, Chapter 487, 1983. State of Wisconsin, Act 410, 1983. State of California, Pending Legislation, Jones AB2133, 1985. "Groundwater Position Paper," National Agricultural Chemicals Association: Washington, D.C., 1984. "Groundwater Management by Use Classification," Chemical Manufacturers Association: Washington, D.C., 1983. Davidson, I. W. F., et. al. Chloroform: A Review of its Metabolism Teratogenic, Mutagenic and Carcinogenic Potential. Drug and Chem. Toxicol. 1982, 5, 1-87. "Pesticide Reference Standards and Supplemental Data," Office of Research and Development, US - EPA Research Triangle Park, NC, 1973. Loomis, T. A. "Essentials of Toxicology" 2nd Ed.; Lea and Febiger: Philadelphia, 1974. CIBA-GEIGY Corporation, Internal Communications. Innes, J. R. M., et. al. Bioassay of Pesticides and Industrial Chemicals for Tumorigenicity in Mice. A Preliminary Note. J . Nat. Cancer Inst. 1969, 42, 1101-1114.


444 17.

18. 19. 20. 21.


22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.

33. 34. 35. 36.


Weaver, D. J., et. al. "Pesticide Movement to Groundwater, Volume I Survey of Groundwater Basins for DBCP, EDA, Simazine and Carbofuran"; State of California, Department of Food and Agriculture": Sacramento, CA, 1983. Roux, P., personal communication. "Partially Closed Meeting of FIFRA Science Advisory Panel," Federal Register, 50, 25783, EPA, 1985. "Drinking Water and Health Report of the Safe Drinking Water Committee," National Academy of Sciences - National Research Council, Washington, 1977. Hayes, A. W. "Principles and Methods of Toxicology"; Raven Press: New York, 1982. Crump, K. S.; Guess, H. A. "Drinking Water and Cancer: Review of Recent Findings and Assessment of Risks." Science Research Systems, Inc.: Ruston, LA., CEQ Contract No. EQ10AC018. Crump, K. S., et. al. Confidence Intervals and Tests of Hypothesis Concerning Dose Response Relations Inferred from Animal Carcinogenicity Data, Biometrics 1977, 33, 437. Mantel, N. and W. R. Bryan. "Safety" Testing of Carcinogenic Agents. J . Nat'l. Cancer Inst. 1961, 27, 455-470. "Chemical Carcinogens: Review of the Science and its Associated Principles", Office of Science and Technology Policy, Fed. Reg. 49, 21595-21661, 1984. "Hazard Evaluation Human and Domestic Animals" Pesticide Assessment Guidelines Subdivision F, EPA, PB, 82-153916, NTIS 1982. "Chemistry; Environmental Fate" Pesticide Assessment Guidelines Subdivision N, EPA, 83-153973, NTIS, October, 1982. "Hazard Evaluation: Wildlife and Aquatic Organisms PB" Pesticide Assessment Guidelines Subdivision E, EPA, 83-153908 NTIS, October, 1982. Casarett, L. F.; Doull, J. "Toxicology the Basic Science of Poisons" 2nd Ed.; Macmillan: New York, 1975. "Report of the Safe Drinking Water Committee," National Academy of Sciences, National Research Council Drinking Water and Health Volume 3, Washington, 1980. "Relationship Between Tolerances and Actual Daily Intake of Pesticides" FAO/WHO Food Standards Programme, World Health Organization, Geneva, 1974. Frawley, J. and R. Duggan. "Techniques for Deriving Realistic Estimates of Pesticide Intakes from Advances in Pesticide Science", Part 3.; H. Geissbuehler Ed.; Pergamon Press: Oxford, 1979. Lehman, A. J.; Fitzhugh, O. G. 100-Fold Margin of Safety Assoc. Food Drug 088. Q. Bull. 1954, 18, 33-35. Lappenbusch, L . ; S. Moskowitz Proc. ΑΜΑ/EPA Symp. on Drinking Water and Human Health, Washington, DC, 1984. "Proposed Changes to Subdivision 701", State of New York, 1985. Stara, G. "Evaluation of Pesticides in Groundwater"; Division of Pesticide Chemistry; American Chemical Society: Washington, D.C., 1985.

RECEIVED March 25, 1986


Safety Evaluation of Pesticides in Ground Water - ACS Publications

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