National Agricultural Chemicals Association Overview on Assessment

Chapter 28

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 20, 2018 | https://pubs.acs.org Publication Date: December 23, 1988 | doi: 10.1021/bk-1988-0382.ch028

National Agricultural Chemicals Association Overview on Assessment of Mixer-Loader-Applicator Exposure to Pesticides Biological Monitoring Richard C. Honeycutt National Agricultural Chemicals Association, 1155 15th Street, NW, Washington, DC 20005

Agricultural worker exposure to pesticides is rapidly becoming a major issue in occupational health. With this in mind, the National Agricultural Chemical Association (NACA) along with member companies has over the past few years begun to throughly address this issue. The objective of this paper is to present an overview of how NACA regards mixer-loader-applicator exposure assessment. This paper w i l l briefly consider a historical perspective on the NACA viewpoint on worker exposure and discuss the development of the NACA protocol for worker exposure as well as the development of the NACA - EPA public worker exposure data base to be used for surrogate or generic estimation of mixer-loader-applicator exposure. This paper w i l l also deal with specific field methods of measuring mixer-loader -applicator exposure including biological monitoring that are common ly used by U.S. companies and supported in the published NACA proto col. Finally, directions for future research in field worker expo sure technology will be considered. A H i s t o r i c a l Perspective sure Research

o f NACA Involvement i n F i e l d Worker Expo-

In September 1983, NACA formed an ad hoc subcommittee on worker exposure assessment. The g o a l o f t h i s subcommittee was t o b r i n g t o g e t h e r t e c h n i c a l l e v e l e x p e r t s from s e v e r a l member companies i n v o l v e d d i r e c t l y i n p e r f o r m i n g f i e l d w o r k e r exposure s t u d i e s t o a s s e s s and advance the s t a t e o f the a r t i n m i x e r - l o a d e r - a p p l i c a t o r exposure t o p e s t i c i d e s . T h i s subcommittee ( p a r t o f t h e NACA P u b l i c H e a l t h and T o x i c o l o g y Committee) has a c c o m p l i s h e d t h e f o l l o w i n g object ives: 0097-6156/89/0382-0368$06.00/0 ° 1989 American Chemical Society

Wang et al.; Biological Monitoring for Pesticide Exposure ACS Symposium Series; American Chemical Society: Washington, DC, 1988.

28. HONEYCUTT 1. 2. 3.


4.

369

Mixer—Loader—Applicator Exposure

Developed a NACA p r o t o c o l f o r p e r f o r m i n g f i e l d worker e x p o s u r e studies. T h i s p r o t o c o l was p u b l i s h e d i n 1985. Supported and a s s i s t e d EPA i n t h e development o f a j o i n t NACA EPA - p u b l i c g e n e r i c d a t a b a s e . Developed and c o o r d i n a t e d r e s e a r c h t o improve e x p o s u r e moni t o r i n g t e c h n o l o g y (e.g., R. Fenske's r e s e a r c h on F l u o r e s c e n t Tracer Technology). I n t e r a c t e d w i t h s t a t e and f e d e r a l r e g u l a t o r y a g e n c i e s t o r e s o l v e i s s u e s o f mutual i n t e r e s t on m i x e r - l o a d e r - a p p l i c a t o r exposure assessment.

The communication w i t h EPA i n t h e development o f t h e worker-exposure p r o t o c o l and t h e g e n e r i c d a t a b a s e have been t i m e l y and have had some impact on r e g u l a t o r y p o l i c y a t EPA i n r e c e n t months. This i s r e f l e c t e d i n t h e f a c t t h a t t h e NACA p r o t o c o l and EPA Subpart U g u i d e l i n e s a r e q u i t e s i m i l a r . In a d d i t i o n t h e EPA-NACA - p u b l i c d a t a base w i l l save i n d u s t r y c o n s i d e r a b l e r e s o u r c e s i n time and money on f u t u r e exposure s t u d i e s . Development o f t h e NACA P r o t o c o l c a t o r Exposure S t u d i e s

for Conducting

Mixer-Loader-Appli

The NACA p r o t o c o l on worker exposure was d e v e l o p e d between 1983-1985 by t h e NACA submcommittee. The o b j e c t i v e s o f t h e p r o t o c o l were t o s t a n d a r d i z e the methodology f o r f i e l d exposure s t u d i e s w i t h i n i n d u s t r y and g i v e d i r e c t i o n t o new r e s e a r c h e r s i n t h i s f i e l d . The NACA p r o t o c o l i s c o n s i s t e n t w i t h t h e WHO p r o t o c o l on worker exposure. Comments on t h e NACA p r o t o c o l were a l s o s o l i c i t e d from EPA and i t i s g e n e r a l l y f e l t among the subcommittee members t h a t t h e A p p l i c a t o r E x p o s u r e M o n i t o r i n g G u i d e l i n e s ( S u b p a r t U) p u b l i s h e d by EPA i n 1987 (1) r e f l e c t many methods s i m i l a r t o t h o s e i n t h e NACA protocol. A listing 1. 2. 3.

4.

5.

o f the g e n e r a l

c o n t e n t s o f t h e NACA p r o t o c o l

follows:

E v a l u a t i o n o f the need f o r a f i e l d s t u d y . P r o c e d u r e s f o r a d m i n i s t r a t i o n o f a f i e l d e x p o s u r e s t u d y , e.g., s e l e c t i o n o f the work crew. While t h e g e n e r a l n a t u r e o f t h e p r o t o c o l i s s t a n d a r d i z a t i o n , exposure assessment t e c h n i q u e s a r e f l e x i b l e g i v i n g the r e s e a r c h e r some l a t i t u d e i n methodology. F i e l d d a t a c o l l e c t i o n forms a r e p r e s e n t e d i n o r d e r t o s t a n d a r d i z e r e p o r t i n g and add q u a l i t y a s s u r a n c e . C a l c u l a t i o n methods are a l s o i n c l u d e d . Appendices a r e a t t a c h e d which p r o v i d e d e t a i l e d methodology f o r researchers with l i t t l e experience i n t h i s f i e l d .

These NACA g u i d e l i n e s p o i n t out t h a t t h e e x i s t i n g p a t c h method o f exposure assessment, w h i l e t h e o r e t i c a l l y n o t t h e most r e l i a b l e meth od, i s the method o f c h o i c e i n the U.S. The NACA p r o t o c o l r e c o g n i z e s t h e s h o r t comings o f such an e m p i r i c a l method. However, t h e only current a l t e r n a t i v e , B i o l o g i c a l Monitoring, while t h e o r e t i c a l l y the s u p e r i o r method, has n o t been d e v e l o p e d t o a p o i n t o f g e n e r a l implementation o r t o a p o i n t o f r e g u l a t o r y impact. This i n d i r e c t


370

BIOLOGICAL MONITORING FOR PESTICIDE EXPOSURE

method r e q u i r e s c o n s i d e r a b l e s u p p o r t s t u d i e s t o make t h e d a t a i n t e r pretable. Such s t u d i e s are d i s c u s s e d below and as you w i l l see a r e complex and e x p e n s i v e .


A D i s c u s s i o n of S p e c i f i c F i e l d Methods as Recommended by the NACA P r o t o c o l f o r M i x e r - L o a d e r - A p p l i c a t o r Exposure Assessment Measuring I n h a l a t i o n Exposure: C u r r e n t l y i n the U.S. i n d u s t r y i t i s r e c o g n i z e d t h a t i n h a l a t i o n exposure t o p e s t i c i d e s i s o n l y a s m a l l f r a c t i o n ( 1%) o f dermal exposure. There a r e , however, a few i n s t a n c e s when i n h a l a t i o n exposure can be c r i t i c a l such as a Category I p e s t i c i d e t h a t may be h i g h l y v o l a t i l e . In t h i s case r e s p i r a t o r p r o t e c t i o n w i l l be r e q u i r e d . I n h a l a t i o n exposure i s somewhat d i f f i c u l t t o measure i n a f i e l d study. The NACA p r o t o c o l p r e f e r r e d method i s t o use p e r s o n a l samp l i n g d e v i c e s w h i c h a r e c a l i b r a t e d t o an a i r f l o w o f 4 1 i t e r s / m i n u t e . A p p r o p r i a t e c a l i b r a t i o n and r e t e n t i o n c o n t r o l s are n e c e s s a r y t o v a l i d a t e t h i s method. M o d i f i e d R e s p i r a t o r s u t i l i z i n g gauze pads as d e s c r i b e d by Duhram and Wolf a r e a c c e p t a b l e but have some d i s a d v a n t ages, such as ease o f c o n t a m i n a t i o n and i n c o n v e n i e n c e t o the t e s t s ub j e c t . Measuring Dermal Exposure: The NACA p r o t o c o l c a l l s f o r use o f t h e c l a s s i c a l p a t c h method t o measure dermal exposure. Gauze pads o r - c e l l u l o s e pads are commonly used w i t h a b a c k i n g m a t e r i a l such as aluminum f o i l o r a p l a s t i c f i l m . Patches a r e g e n e r a l l y p l a c e d i n s i d e or o u t s i d e the c l o t h i n g . Recent advances i n t e c h n o l o g y have shown t h a t patches can be c o v e r e d w i t h a chambray o r denim c o v e r t o s i m u l a t e i n s i d e p a t c h e s . These " i n s i d e " patches as w e l l as uncovered patches can a l l be worn on t h e o u t s i d e o f work c l o t h i n g f o r convenience. I t i s now r e c o g n i z e d t h a t hand exposure i s the major component of t o t a l exposure f o r m i x e r - l o a d e r s and i s f a r g r e a t e r than f o r any o t h e r t y p e o f exposure i n v o l v i n g p e s t i c i d e s . Hand wash p r o c e d u r e s f o r measuring hand exposure a r e commonly used i n the i n d u s t r y . Hand exposure can a l s o be measured by u s i n g adsorbent c o t t o n g l o v e s , a l t h o u g h t h i s t e c h n i q u e may o v e r e s t i m a t e exposure. C a l c u l a t i n g T o t a l Dermal Exposure from P a t c h Data: T o t a l dermal exposure i s g e n e r a l l y c a l c u l a t e d u s i n g i n d i v i d u a l p a t c h d a t a . The amount o f p e s t i c i d e per cm^ on a p a t c h i s m u l t i p l i e d by the s p e c i f i c body a r e a i n q u e s t i o n ( e . g . , c h e s t , neck, arm, l e g , e t c . ) . T h i s procedure may l e a d t o c o n s i d e r a b l e e r r o r i f patches a r e s m a l l . Thus, i t i s d e s i r a b l e t o maximize t h e s i z e o f t h e p a t c h e s used. These e l e m e n t a l exposures are then summed t o g i v e t o t a l body exposure. I t i s p r e f e r a b l e t o e x p r e s s r e s u l t s i n terms o f amount o f exposure per pound a i handled o r per l o a d h a n d l e d . Maximum exposure v a l u e s a r e c a l c u l a t e d by d e t e r m i n i n g t h e t o t a l pounds handled/day o r the number of loads/day. Measuring Exposure U s i n g B i o l o g i c a l M o n i t o r i n g : The term b i o l o g i c a l m o n i t o r i n g r e f e r s t o any method w h i c h d e r i v e s exposure from meas u r i n g parent or m e t a b o l i t e s i n body f l u i d s . The use o f b i o l o g i c a l m o n i t o r i n g i s the most e f f e c t i v e means f o r measuring t o t a l dose o r


28. HONEYCUTT

Mixer-Loader-Applicator Exposure

371


body burden. Use o f t h i s t e c h n i q u e r e s o l v e s many problems a s s o c i a t e d w i t h the patch t e c h n i q u e i n c l u d i n g o v e r e s t i m a t i o n o f dermal exposure. The NACA p r o t o c o l c o n s i d e r s B i o l o g i c a l M o n i t o r i n g t o be an i n d i r e c t method and must be accompanied by adequate s u p p o r t i n g s t u d i e s t o d e f i n e the a b s o r p t i o n , metabolism, p h a r m a c o k i n e t i c s and e x c r e t i o n o f the p a r e n t / m e t a b o l i t e s i n humans o r an a p p r o p r i a t e s u r r o g a t e animal. These s t u d i e s d e f i n e t h e q u a n t i t a t i v e r e l a t i o n s h i p between dose and e x c r e t i o n o f the p e s t i c i d e and i t s meta bolites. I w i l l b r i e f l y d e s c r i b e t h e s e r e q u i r e m e n t s below: Criteria

f o r U t i l i z a t i o n of B i o l o g i c a l

Monitoring

A.

Dermal A b s o r p t i o n - Dermal a b s o r p t i o n s t u d i e s s h o u l d be p e r formed on a p p r o p r i a t e s p e c i e s ( t h e use o f r a t s , monkeys o r p i g s are common). In v i t r o dermal a b s o r p t i o n s t u d i e s a r e g a i n i n g i n popularity. The p e s t i c i d e i n q u e s t i o n must be absorbed t o an a p p r o p r i a t e e x t e n t o v e r an 8-hour work day b e f o r e b i o l o g i c a l m o n i t o r i n g can be used as an e f f e c t i v e t o o l .

B.

P h a r m a c o k i n e t i c s - P h a r m a c o k i n e t i c and e x c r e t i o n k i n e t i c s i n a p p r o p r i a t e s u r r o g a t e a n i m a l s o r man must be u n d e r s t o o d . Multi p l e s p e c i e s s h o u l d be t e s t e d s i n c e the chance o f one s p e c i e s e x c r e t i o n p a t t e r n b e i n g d i f f e r e n t from the o t h e r i s c o n s i d e r able. I d e a l l y , e x c r e t i o n of parent/metabolites should occur o v e r the f i r s t 24 hours a f t e r o r a l d o s i n g and w i t h i n a few days a f t e r dermal d o s i n g . In a d d i t i o n , a l a r g e p e r c e n t a g e o f the dose s h o u l d be e x c r e t e d i n t o u r i n e .

C.

A n a l y t i c a l Method - The a n a l y t i c a l method must measure e x c r e t e d p a r e n t and m e t a b o l i t e s and account f o r a l a r g e p e r c e n t a g e o f the e x c r e t e d compounds. The s e n s i t i v i t y o f the a n a l y t i c a l method must be enough t o d e t e c t exposure a t and below t h e t o x i c o l o g i c a l end p o i n t c o n c e n t r a t i o n . E x t e n s i v e m e t a b o l i s m makes b i o l o g i c a l m o n i t o r i n g e x t r e m e l y d i f f i c u l t and makes i t e x p e n s i v e t o d e v e l o p s u p p o r t i n g p h a r m a c o k i n e t i c and a n a l y t i c a l methods.

D.

Convenience t o and C o o p e r a t i o n o f F i e l d Workers - U r i n e m o n i t o r i n g o f a g r i c u l t u r a l workers i s d i f f i c u l t . C o l l e c t i n g 24-hour u r i n e s c a r r i e s w i t h i t c o n s i d e r a b l e l o s s o f c o n t r o l o f the experiment s i n c e workers g e n e r a l l y t a k e a c a s u a l a t t i t u d e toward their responsibility. A c t i v i t y p a t t e r n s may a l s o a p p r e c i a b l y change u r i n a r y o u t p u t by a l t e r i n g p e r s p i r a t i o n r a t e s . A l s o , l i q u i d i n t a k e can a l t e r u r i n e o u t p u t . Measurement o f c r e a t i n i n e (WHO p r o t o c o l ) can overcome some o f t h e s e p o t e n t i a l problems s i n c e c r e a t i n i n e e x c r e t i o n i s c o n s t a n t over time and measurement a l l o w s one t o e s t i m a t e t o t a l e x c r e t i o n volume. A d d i t i o n a l problems may a r i s e i f u r i n e samples a r e t o be t a k e n on a l o n g - t e r m b a s i s . Of c o u r s e , B i o l o g i c a l M o n i t o r i n g o f body t i s s u e s such as b l o o d i s an i n t r u s i v e method and s h o u l d always be accompanied by m e d i c a l s u r v e i l l a n c e and s u p e r v i s i o n t o a v o i d p o t e n t i a l problems.



372 Costs 1.

for Biological

Monitoring:

Dermal A b s o r p t i o n

Studies

Rat Model $70,000 Monkey Model - $100,000 In V i t r o Models $25,000


2.

3.

Pharmacokinetic

Excretion Studies

Rat Model Monkey Model

-

$65,000 $20,000

A n a l y t i c a l Method Development M e t a b o l i s m S t u d i e s (2 s p e c i e s ) - $200,000 Method Development 2 Major M e t a b o l i t e s $40,000 M u l t i p l e M e t a b o l i t e s - $100,000 Method V a l i d a t i o n $10,000

Examples o f Uses o f B i o l o g i c a l M o n i t o r i n g o f P e s t i c i d e s by I n d u s t r y : T h e r e a r e a few companies w h i c h have d e v e l o p e d b i o l o g i c a l m o n i t o r i n g f o r s p e c i f i c p e s t i c i d e s and f o r s p e c i f i c p u r p o s e s . Dow Chemical - S c i e n t i s t s a t Dow Chemical were some o f the f i r s t t o d e v e l o p u r i n e m o n i t o r i n g as a t o o l f o r e x p o s u r e assessment. In a 1982 r e v i e w a r t i c l e by Leng, Levy and o t h e r s ( 2 ) , i t was shown t h a t exposure t o 2.4,5T c o u l d be measured r e l i a b l y and i n f a c t u r i n a r y e x c r e t i o n p r o v i d e d a more r e l i a b l e measure o f dose than a n a l y s i s o f patch data. Monsanto - S c i e n t i s t s at Monsanto have r e c e n t l y performed s u p p o r t i n g s t u d i e s f o r b i o l o g i c a l m o n i t o r i n g o f Lasso® f o r m i x e r - l o a d e r a p p l i cators. These s u p p o r t i n g s t u d i e s meet many o f the c r i t e r i a l i s t e d above. R e s e a r c h e r s a t Monsanto p o i n t out t h a t m u l t i p l e s p e c i e s s t u d i e s a r e o f g r e a t importance i n t h e i r e x p e r i e n c e and t h a t when a p p r o p r i a t e s u p p o r t i n g s t u d i e s a r e performed, p a t c h and u r i n e d a t a are q u i t e c o m p a t i b l e . CIBA-GEIGY - S c i e n t i s t s at CIBA-GEIGY have u t i l i z e d b i o l o g i c a l m o n i t o r i n g i n a h i g h l y p r a c t i c a l manner. Over the p a s t s e v e n y e a r s , some 50,000 u r i n e samples from a e r i a l a p p l i c a t o r s / m i x e r - l o a d e r s have been a n a l y z e d t o d e t e r m i n e c h l o r d i m e f o r m exposure. A discussion of the r e s u l t s o f these m o n i t o r i n g s t u d i e s a r e beyond the scope o f t h i s presentation. However, the s u p p o r t i n g s t u d i e s w h i c h were used t o d e v e l o p the b i o l o g i c a l m o n i t o r i n g system meet many o f the c r i t e r i a l i s t e d above and the program i s one o f the few t h a t has been u s e d t o study an e n t i r e p o p u l a t i o n o f workers u s i n g b i o l o g i c a l m o n i t o r i n g . T h i s e x t e n s i v e program has overcome one s e r i o u s problem o f the p a t c h method, i . e . , d o i n g enough r e p l i c a t i o n s t o a c h i e v e a r e p r e s e n t a t i v e p o r t i o n o f the p o p u l a t i o n o f workers and t h e i r work h a b i t s .


28. HONEYCUTT

Mixer-Loader-Applicator Exposure


Development o f a G e n e r i c Data Base t o E s t i m a t e t o r Exposure

373

Mixer-Loader-Applica

Development o f a g e n e r i c exposure d a t a base i s one o f t h e major p r o j e c t s which t h e NACA subcommittee on exposure assessment h a s been working on f o r 2 y e a r s . T h i s d a t a base was f i r s t proposed d u r i n g a NACA subcommittee m e e t i n g and p u t f o r t h a t a p e s t i c i d e d i v i s i o n symposium a t the ACS meeting i n S t . L o u i s , M i s s o u r i i n 1983 ( 3 ) . L a t e r , NACA and EPA agreed t o j o i n t l y d e v e l o p t h i s d a t a base. P u b l i c groups were i n v i t e d t o p a r t i c i p a t e i n t h i s p r o j e c t . The purpose o f t h e g e n e r i c d a t a b a s e i s t o p r o v i d e e q u i v a l e n t m i x e r - l o a d e r - a p p l i c a t o r exposure d a t a t o EPA, i n d u s t r y and t h e pub l i c i n o r d e r t o s t a n d a r d i z e exposure e s t i m a t e s . It i s w e l l r e c o g n i z e d t h a t m i x e r - l o a d e r - a p p l i c a t o r exposure i s a f u n c t i o n o f formu l a t i o n and t y p e o f a p p l i c a t o r equipment and t h a t a d a t a b a s e c o u l d be developed t o c o o r d i n a t e a l l a v a i l a b l e exposure d a t a f o r worker exposure and r i s k assessment. T h i s would add s t a t i s t i c a l c r e d i b i l i ty t o s m a l l pockets o f d a t a which i n themselves were weak i n c r e d i b i l i t y m a i n l y due t o t h e number o f r e p l i c a t e s performed. Ground r u l e s f o r development o f the d a t a base have been l a i d out o v e r t h e p a s t y e a r i n s e v e r a l meetings between EPA and NACA representatives. EPA has c o n t r i b u t e d $145,000 and Canada r e g u l a t o r y o f f i c i a l s $40,000 ( C a n a d i a n ) . EPA i s committed t o t h e d a t a base development and w i l l r e g u l a t e w i t h t h e d a t a . C r i t e r i a have been selected to evaluate a l l studies f o r a c c e p t a b i l i t y i n t o the data base. Both i n d u s t r y and academic s t u d i e s w i l l be e v a l u a t e d . Data w i l l be e n t e r e d and r e t r i e v e d on a p a t c h by p a t c h b a s i s . The u s e r can b u i l d a "Body P a r t s " s u r r o g a t e model f o r any s c e n a r i o d e s i r e d (e.g., protected vs. nonprotected). There a r e s e v e r a l advantages f o r EPA, the p u b l i c and i n d u s t r y t o have t h i s d a t a base i n p l a c e . 1.

2.

3. 4.

Data at EPA on which r e g u l a t o r y d e c i s i o n s a r e based w i l l be expanded and i t s c r e d i b i l i t y s t r e n g t h e n e d . Also, the r e l i a b i l i ty and s t a t i s t i c a l power o f the Agency's r i s k assessments f o r workers w i l l be improved. I n d u s t r y w i l l i n c u r c o s t s a v i n g s o f $200,000-$500,000 p e r y e a r s i n c e EPA w i l l not r e q u i r e f i e l d s t u d i e s where s u f f i c i e n t d a t a e x i s t s t o perform a surrogate estimate. Use o f a m u t u a l l y agreed upon d a t a base w i l l reduce c o n t e n t i o n i n t h e exposure o f t h e r i s k assessment p r o c e s s . P u b l i c use o f the d a t a base w i l l r e s u l t i n a b e t t e r u n d e r s t a n d i n g o f t h e r i s k assessment p r o c e s s f o r a g r i c u l t u r a l c h e m i c a l s .

The NACA - EPA j o i n t committee has made s i g n i f i c a n t p r o g r e s s o v e r the p a s t few months i n i m p l e m e n t a t i o n o f t h e d a t a base. VERSAR, Inc. has agreed t o r e v i e w s t u d i e s w i t h d e v e l o p e d c r i t e r i a o f v a l i d i t y and t o i n p u t t h e d a t a i n t o s t o r a g e . R e t r i e v a l by i n d u s t r y w i l l be through computer hookup. R e t r i e v a l by EPA and t h e p u b l i c w i l l be through t h e NTIS.


374


Future Research I s s u e s f o r

the NACA

Subcommittee


The NACA subcommittee on exposure w i l l c o n t i n u e t o m o n i t o r the p r o g r e s s o f t h e d a t a base as w e l l as l o o k a t o t h e r e x p o s u r e i s s u e s ; areas such as B i o l o g i c a l M o n i t o r i n g w i l l be h i g h on our l i s t o f activities. Other a c t i v i t i e s w i l l be t o a d d r e s s r e e n t r y r e s e a r c h as w e l l as r e s e a r c h i n dermal p e n e t r a t i o n , improvement i n exposure assessment t e c h n o l o g y (Fenske) and r e s e a r c h i n e x p o s u r e r e d u c t i o n technology. Conclusions: 1.

2. 3. 4.

NACA ad hoc subcommittee on p e s t i c i d e worker exposure i s and w i l l c o n t i n u e t o a d d r e s s p r o c e d u r e s f o r m e a s u r i n g worker expo sure . NACA g u i d e l i n e s f o r e x p o s u r e assessment have been d e v e l o p e d and agree i n p r i n c i p l e w i t h EPA Subpart U. A g e n e r i c exposure d a t a base i s b e i n g d e v e l o p e d and s h o u l d be i n p l a c e by mid 1988. In t h e f u t u r e t h e NACA subcommittee w i l l a d d r e s s ; r e e n t r y ; B i o l o g i c a l M o n i t o r i n g ; improved exposure assessment t e c h n o l o g y and exposure r e d u c t i o n t e c h n o l o g y .

REFERENCES 1.

Reinert, J. C. et. a l . , Pesticide Assessment Guidelines, Sub division U, Applicator Exposure Monitoring, U.S. Environmental Protection Agency, October 1986.

2.

Leng, M. L . , Ramsey, J. C., Braun, W. H., Lavy, T. L. "Review of Studies with 2,4,5-Trichlorophenoxyacetic acid in Humans Including Applicators under Field Conditions," American Chemical Symposium Series 182, p. 133-156, Editor: J. Plimmer, American Chemical Society, Washington, D.C. (1982).

3.

Hackathorn, D. R., Eberhart, D. C., "Data Base Proposal for Use in Predicting Mixer-Loader-Applicator Exposure," American Chemical Society Symposium Series 273, p. 341-351, Editors: Honeycutt, R. C., Zweig, G., Ragsdale, N. N., American Chemical Society, Washington, D.C. (1985).

RECEIVED

June 7, 1988


National Agricultural Chemicals Association Overview on Assessment

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