Use of Biological Monitoring Data from Pesticide Users in Making

Chapter 26

Use of Biological Monitoring Data from Pesticide Users in Making Pesticide Regulatory Decisions in California Study of Captan Exposure of Strawberry Pickers 1

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Keith T. Maddy , R. I. Krieger , Linda O'Connell , M . Bisbiglia , and S. Margetich 2

Downloaded by AUBURN UNIV on October 16, 2017 | http://pubs.acs.org Publication Date: December 23, 1988 | doi: 10.1021/bk-1988-0382.ch026

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California Department of Food and Agriculture, 1220 N Street, Sacramento, CA 95814 California Department of Food and Agriculture, 3292 Meadowview Road, Sacramento, CA 95832

Exposure of users of p e s t i c i d e s c o n t a i n i n g a c t i v e ingredients which have the potential of causing adverse effects, especially those of subchronic and chronic types, has to be accurately measured i n order to make meaningful risk mitigation determinations. Acceptable methodology is usually available to measure inhalation exposure, however, most pesticide exposure is dermal. Analysis of residues on cloth pads that had been on various parts of the body during exposure may provide an overestimate of dermal exposure. Availability of dermal absorption-rate data i n rodents is useful, but at least on some chemicals it is more l i k e l y to overestimate exposure than such studies done on humans or other primates. The most useful data results from development of metabolism data i n humans or a suitable test animal with appropriate pharmacokinetics, including excretory data, and then biologically monitoring blood, urine, s a l i v a or feces of persons being exposed to the chemical under normal use conditions. As an example results of recent measurements of mixer/loader/applicator and hand harvest worker exposures to captan i n strawberry fields included dislodgeable residues, dermal dosimetry, and urine monitoring. Calculation of the urinary levels resulted i n substantially reduced estimates of human exposure. Such data are used to reach safety and regulatory decisions. The goal is to avoid an inaccurate estimate of exposure that can result from less direct methods of exposure assessment. The k i n d s o f worker exposure d a t a needed b y C a l i f o r n i a have been d e s c r i b e d i n two p r e v i o u s r e p o r t s : " P e s t i c i d e S a f e t y Program o f The C a l i f o r n i a D e p a r t m e n t o f F o o d a n d A g r i c u l t u r e B a s e d Upon Measurements o f P o t e n t i a l Workplace Exposure and t h e E l i m i n a t i o n o f Excess E x p o s u r e s " ( 1 ) , and " R i s k Assessment o f E x c e s s P e s t i c i d e Exposure t o Workers i n C a l i f o r n i a " (2) . California i n i t s Department o f Food and A g r i c u l t u r e (CDFA) h a s a more r e s t r i c t i v e p e s t i c i d e r e g u l a t o r y program t h a n t h e U.S. Government o r o f any

c

0097-6156/89/0382-0338$06.00/0 1989 American Chemical Society

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


26. MADDY ET AL.

Monitoring Data in Regulatory Decisions

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other s t a t e i n the U n i t e d States. C a l i f o r n i a a l s o r e q u i r e s more b a s i c t o x i c o l o g y d a t a and exposure d a t a t h a n t h e U.S. E.P.A.in o r d e r t o meet r e c e n t l y imposed t o x i c o l o g y t e s t s t a n d a r d s , b o t h on new r e q u e s t s f o r r e g i s t r a t i o n as w e l l as f o r a n e x t e n s i v e r e r e g i s t r a t i o n and r e e v a l u a t i o n program w h i c h i s now underway. I n C a l i f o r n i a more t h a n 13,000 p r o d u c t s a r e c u r r e n t l y r e g i s t e r e d on an a n n u a l b a s i s w h i c h c o n t a i n more t h a n 700 a c t i v e p e s t i c i d e i n g r e d i e n t s a n d a l m o s t 1000 c h e m i c a l s w h i c h a r e " i n e r t " as p e s t i c i d e s b u t w h i c h may be q u i t e t o x i c t o man. S i n c e 1971, new C a l i f o r n i a laws have emphasized r e q u i r e m e n t s f o r assessing workplace hazards f o r p e s t i c i d e users ( i n c l u d i n g l o n g - t e r m exposure h a z a r d s ) and ways o f m i t i g a t i n g t h e s e h a z a r d s . T h i s has r e s u l t e d i n s p e c i f i c C a l i f o r n i a r e q u i r e m e n t s f o r d a t a w h i c h may be used t o e s t i m a t e t h e e x t e n t o f such h a z a r d s . The p e s t i c i d e s a f e t y program o f CDFA r e q u i r e s t h e p r e s e n t a t i o n and c o n s i d e r a t i o n o f d a t a on : 1) p e s t i c i d e v a p o r s , m i s t s , o r d u s t s i n t h e b r e a t h i n g zone o f exposed p e r s o n s ; 2) p e s t i c i d e d u s t s , powders o r l i q u i d s on t h e s k i n o f p e r s o n s m i x i n g , l o a d i n g , and/or a p p l y i n g p e s t i c i d e s ; 3) p e s t i c i d e r e s i d u e s , i n c l u d i n g t h e more t o x i c breakdown p r o d u c t s , on f o l i a g e and i n s o i l o f f i e l d s where w o r k i s t o t a k e p l a c e w h i c h may l a t e r c o n t a c t s k i n ; a n d , 4 ) r e s i d u e s i n t h e a i r , on f l o o r s , c o u n t e r s , f u r n i t u r e e t c . , f o l l o w i n g a p p l i c a t i o n of p e s t i c i d e s indoors. These measurements a r e o f v a l u e i n d e s i g n i n g methods t o reduce exposure t o p e r s o n s a g r i c u l t u r a l l y exposed, such as commercial a g r i c u l t u r a l a p p l i c a t o r s , b u t a l s o t o p e r s o n s who use p e s t i c i d e s i n non-agricultural settings. CDFA e v a l u a t e s b a s i c t o x i c o l o g y d a t a , exposure measurements and t h e manner i n which t h e p e s t i c i d e p r o d u c t i s t o be used. By m o d i f y i n g t h e way t h e p e s t i c i d e i s t o be used, e s t a b l i s h i n g r e e n t r y i n t e r v a l s , o r s u g g e s t i n g changes t o EPA o f p r e c a u t i o n a r y s t a t e m e n t s on p e s t i c i d e l a b e l s (which t h e y t h e n agree t o make), t h e r i s k o f exposure t o a p o t e n t i a l l y hazardous p e s t i c i d e may be g r e a t l y reduced. In the p a s t , a major d i f f i c u l t y i n c o n d u c t i n g h a z a r d assessments f o r any persons who might be exposed b e f o r e , d u r i n g , and a f t e r a p e s t i c i d e a p p l i c a t i o n was t h e l a c k o f i n f o r m a t i o n on the amount o f p e s t i c i d e t h a t might be i n h a l e d o r might r e a c h t h e s k i n , t h e r a t e a n d amount o f d e r m a l a b s o r p t i o n , t h e r a t e a n d pathway o f b i o t r a n s f o r m a t i o n , and t h e r o u t e and r a t e o f e l i m i n a t i o n from t h e body. Some o f t h e s p e c i f i c d a t a t h a t may be r e q u i r e d by CDFA t o a s s i s t i n making exposure e s t i m a t e s o f persons i n v a r i o u s a c t i v i t i e s i n v o l v i n g the use o f p e s t i c i d e s i n c l u d e : i n d o o r exposure; f i e l d r e e n t r y exposure; m i x e r , l o a d e r , and a p p l i c a t o r exposure, m e t a b o l i s m , dermal a b s o r p t i o n r a t e , dermal dose response d a t a and b i o l o g i c a l m o n i t o r i n g d a t a . TYPES OF EXPOSURE DATA

I n d o o r Exposure. P e s t i c i d e p r o d u c t s t o be used i n d o o r s such as i n houses, apartments, o f f i c e s , o t h e r i n s t i t u t i o n s , and greenhouses may have exposure ( i n h a l a t i o n , dermal, and i n g e s t i o n ) h a z a r d s b o t h d u r i n g t h e a p p l i c a t i o n and upon r e e n t r y . A p a r t from p r o t e c t i v e measures f o r a p p l i c a t o r s , an a p p r o p r i a t e v e n t i l a t i o n p e r i o d may be


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BIOLOGICAL MONITORING FOR PESTICIDE EXPOSURE


needed to protect residents, inhabitants, or workers in the treated area from i n h a l a t i o n of hazardous chemicals i n a d d i t i o n to mitigation measures such as reentry periods directed at reducing dermal contact of excess r e s i d u e s on c a r p e t s , f u r n i t u r e and countertops. F i e l d Reentry. Certain pesticides pose a potential hazard to persons i f they enter a treated area and have significant contact with treated plants or s o i l . A waiting period long enough to mitigate exposure i s called a reentry i n t e r v a l . The following is a guide used by CDFA in deciding i f reentry data i s needed. Such data w i l l be needed i f the product is to be applied to a commercially grown crop, p a r t i c u l a r l y to i t s foliage or the s o i l , and c u l t u r a l practices (such as pruning or harvesting) of that p a r t i c u l a r crop i n v o l v i n g s u b s t a n t i a l body contact with the f o l i a g e , bark, or s o i l , or exposure to pesticide residues shaken from the f o l i a g e or bark, and the product c o n t a i n s : (a) a cholinesterase i n h i b i t o r ; or (b) a s i g n i f i c a n t l y toxic p r i n c i p l e that can cause a detrimental acute systemic toxic reaction or is suspected of causing a chronic effect, and may be r e a d i l y absorbed through the s k i n or i n h a l e d f o l l o w i n g exposure to p e s t i c i d e residues contacted while conducting usual c u l t u r a l practices; p_r (c) a chemical which causes a significant primary skin i r r i t a n t reaction i n appropriate test animals or man; or (d) a chemical which is a significant skin sensitizer in appropriate test animals or man. Reentry (safe waiting period) intervals are now established on the basis of: (1) data on dermal absorption rates or dermal dose response rates; (2) inhalation and dermal acute t o x i c i t y studies in animal models; (3) f o l i a r and s o i l residue and d i s s i p a t i o n rate data; and, (4) available human exposure data. In the past, acute t o x i c i t y was the major reentry regulatory concern; more recently subacute and chronic t o x i c i t y has also become a major concern. Mixer, Loader. Applicator Exposure. Unless the acute and chronic toxicology data on the formulated product indicates negligible t o x i c i t y ; mixer, loader and applicator exposure data is needed, at least on the use most reasonably expected to give the most r i s k . In order to make an appropriate hazard assessment, information i s needed on the amount of pesticide that may be inhaled and/or reach the skin, or more importantly absorbed during and subsequent to a "typical" application. Metabolism Data. Complete metabolism data in mammals is needed i n order to understand the d i s t r i b u t i o n and excretion of the pesticide and i t s breakdown products. Usually radiotracer studies in rodents are provided to define metabolic pathways. Greater attention needs to be given to defining pathways in accidentally exposed humans. Such data would e s t a b l i s h a b e t t e r experimental b a s i s f o r b i o l o g i c a l monitoring.


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Dermal Absorption Rate Or Dermal Dose Response Rate. Dermal a b s o r p t i o n d a t a which i s u s u a l l y developed i n r a t s o r monkeys, i s needed i n c o n d u c t i n g t h e r i s k assessment f o r f i e l d w o r k e r s , m i x e r s / l o a d e r s , a p p l i c a t o r s , f l a g g e r s , o t h e r p e s t i c i d e u s e r s as w e l l as f o r b y s t a n d e r s ; t h e s e d a t a may a l s o be u s e d i n t h e development o f r e e n t r y i n t e r v a l s . The d a t a p r o v i d e s i n f o r m a t i o n t o c a l c u l a t e how much o f t h e c h e m i c a l e n t e r s t h e body a f t e r i t comes i n t o c o n t a c t w i t h t h e s k i n . Data on monkeys i s c o n s i d e r e d t h e most l i k e l y t o approximate human exposure; o f t e n t h e a b s o r p t i o n by monkey s k i n appears t o be slower than i t i s i n r o d e n t s . B i o l o g i c a l Monitoring. Data c o l l e c t e d on dermal deposition with c u r r e n t methods, when used a l o n g w i t h t h e animal dermal a b s o r p t i o n r a t e o r dermal-dose-response d a t a i s o f t e n assumed t o o v e r e s t i m a t e actual exposure. Metabolism data i s used t o determine 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 parameters and can form t h e b a s i s f o r b i o l o g i c a l monitoring. F o r example, i f a p a r e n t c h e m i c a l o r a u r i n a r y m e t a b o l i t e can be f u l l y c h a r a c t e r i z e d and t e s t e d f o r , t h e n the amount o f t h e c h e m i c a l i n t h e u r i n e o f u s e r s can be m o n i t o r e d as a measure o f i n t e r n a l dose. A t t h e same t i m e , t h e amount o f c h e m i c a l t h a t might be i n h a l e d and t h e amount t h a t f a l l s on t h e s k i n can a l s o be measured. With such d a t a a much more o b j e c t i v e assessment can be made o f t h e a c t u a l exposure. Use o f such d a t a may i n d i c a t e s a f e use even though dermal d e p o s i t i o n d a t a and t h e animal study dermal a b s o r p t i o n r a t e d a t a a l o n e might s i g n a l an unacceptable r i s k . We h a v e p r e v i o u s l y s u m m a r i z e d b i o l o g i c a l m o n i t o r i n g d a t a on about 50 p e s t i c i d e a c t i v e i n g r e d i e n t s ( 3 ) .

HAZARD EVALUATION PROCESS. HAZARD ASSESSMENT RISK CHARACTERIZATION

IDENTIFICATION,

The CDFA c o n d u c t s i t s h a z a r d e v a l u a t i o n p r o c e s s consideration of the f o l l o w i n g f a c t o r s : data

EXPOSURE

based

on t h e

submitted

by t h e

1.

Review o f t h e b a s i c t o x i c o l o g y registrant;

2.

Review o f o t h e r t o x i c o l o g y d a t a a v a i l a b l e t o CDFA ( j o u r n a l a r t i c l e s , CDFA s t u d i e s , computerized n a t i o n a l d a t a banks, texts, etc.);

3.

Human i l l n e s s i n f o r m a t i o n developed by CDFA o r o t h e r s i n v o l v i n g t h e p e s t i c i d e under c o n s i d e r a t i o n o r s i m i l a r pesticides;

4.

A v a i l a b l e exposure d a t a on t h i s p e s t i c i d e o r t h i s c l a s s o f p e s t i c i d e s developed by CDFA o r any o t h e r group; and,

5.

Work p r a c t i c e s known about o r expected the proposed u s e .

i n California for

A h a z a r d e v a l u a t i o n i s much more than a b a s i c t o x i c o l o g y r e v i e w . For example, a s p e c i f i c p e s t i c i d e can be found i n t h e t o x i c o l o g y



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review to be extremely t o x i c ; however, i n the hazard evaluation process, i t may be determined that the product i s to be used i n such small quantities with such specialized equipment that a person could only be overexposed i n the unusual case of equipment f a i l u r e . On the other hand, a product could be found to be of low t o x i c i t y ; but, the most common use might involve long hours of exposure to many workers in orchards while using hand-held spray wands spraying the pesticide above their heads with no protective clothing, due to lack of specification i n the precautionary label statements. In another example, the basic toxicology data for a product may only indicate a moderate t o x i c i t y ; however, in assessing the proposed use of the product mid-summer in a c i t r u s grove i n the San Joaquin V a l l e y , there could be s u b s t a n t i a l c o n v e r s i o n of the a c t i v e ingredient to a highly toxic degradation product in the duff under trees under actual f i e l d conditions which would be hazardous to f i e l d workers. As well as a toxicology assessment, the CDFA evaluation may include: 1.

Determining the use pattern (geographic, climate, equipment-type e t c . ) of the proposed product;

2.

Determining significant possible human exposure hazards;

3.

E v a l u a t i n g the adequacy of use i n s t r u c t i o n s and/or r e g u l a t i o n s that are i n place to inform users of the possible use hazards and how to avoid excess exposure.

4.

E v a l u a t i n g the adequacy of i n f o r m a t i o n provided recognize i l l n e s s due to exposure i f i t occurs;

5.

Determining the adequacy of f i r s t aid information; and,

6.

Examining the management.

availability

of

data

to

support

season,

to

medical

Data from the toxicology base, plus those from the additional health and safety studies, including exposure, that are sometimes required, allow for the estimation and calculation of potential exposure hazards. For some products, experience already gained allows for a quick determination that adherence to the proposed or e x i s t i n g use i n s t r u c t i o n s should r e s u l t i n a low hazard use situation. On the other hand, a number of the p e s t i c i d e s considered for r e g i s t r a t i o n have significant hazards from either a short-term or long-term exposure standpoint. These hazards are e s t i m a t e d a n d / o r c a l c u l a t e d to d e t e r m i n e i f a f a v o r a b l e recommendation on the proposed r e g i s t r a t i o n can be given, and i f n o t , whether a d d i t i o n a l r e s t r i c t i o n s would be expected to acceptably reduce the hazards of use. For example, a p a r t i c u l a r product might be a highly dusty wettable powder with only moderate acute t o x i c i t y but with demonstrated p o t e n t i a l f o r producing c h r o n i c e f f e c t s . The calculations for the hazard evaluation are based upon the t o t a l workday measurement of the skin and inhalation exposure to this



26. MADDY ET AL.


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p e s t i c i d e when i t i s used i n a c c o r d w i t h the l a b e l i n s t r u c t i o n s . The p o t e n t i a l d a i l y dermal dose i s then a d j u s t e d by the e s t i m a t e d 24-hour dermal a b s o r p t i o n r a t e . T h i s f i g u r e i s t h e n added t o the i n h a l a t i o n exposure v a l u e and the sum i s compared t o a n i m a l t e s t d a t a f o r the dose expected t o produce a s p e c i f i c adverse e f f e c t . The s a f e t y f a c t o r f o r t h i s s p e c i f i c e f f e c t w i l l t h e n be c a l c u l a t e d t o determine i f i t i s adequate t o p r o t e c t the w o r k e r s . I n some c a s e s , the exposure assessment might not l e a d t o an a c c e p t a b l e s a f e t y f a c t o r f o r a m i x e r / l o a d e r ; but, i f t h i s product were repackaged i n w a t e r - s o l u b l e p a c k e t s f o r m u l a t e d as a d r y f l o w a b l e o r i f i t were r e f o r m u l a t e d t o be used as a l i q u i d product and t h e n r e q u i r e d t o be t r a n s f e r r e d t h r o u g h a c l o s e d system, t h e h a z a r d might be a c c e p t a b l y reduced. Of p a r t i c u l a r concern a r e p o t e n t i a l adverse e f f e c t s such as c a r c i n o g e n i c i t y and developmental t o x i c i t y ( p r i m a r i l y those w h i c h occur p r i o r to b i r t h ) . Adequacy Of Mitigation Measures. A f t e r a l l r e l e v a n t d a t a are f u l l y e v a l u a t e d , an assessment i s made r e g a r d i n g t h e adequacy of t h e p o s s i b l e m i t i g a t i o n measures t o p r o t e c t workers from hazards of use. The l a b e l w i t h i t s use i n s t r u c t i o n s may be accepted and t h e product may be r e g i s t e r e d w i t h o u t f u r t h e r c o n c e r n . On the o t h e r hand, one o r more of t h e f o l l o w i n g c o n d i t i o n s may be r e q u i r e d b e f o r e the product i s c o n s i d e r e d f o r r e g i s t r a t i o n by the CDFA: (1) the EPA may be a d v i s e d of the d e s i r a b i l i t y of r e q u i r i n g a l a b e l change g i v i n g more s p e c i f i c use i n s t r u c t i o n s , o r the r e g i s t r a n t may r e c o g n i z e t h e n e e d t o a s k EPA f o r s u c h a l a b e l c h a n g e ; ( 2 ) a C a l i f o r n i a r e g u l a t i o n on the use may be enacted (which w i l l have the same e f f e c t as a l a b e l change, but t h i s can t a k e s e v e r a l months t o a c c o m p l i s h ) ; (3) the product may be made a C a l i f o r n i a r e s t r i c t e d o r r e g u l a t e d m a t e r i a l which w i l l a l l o w i m p o s i t i o n of s p e c i f i c p e r m i t r e q u i r e m e n t s o r r e g u l a t i o n s ( t h i s p r o c e s s can a l s o t a k e a number of months); (4) c l o s e d system t r a n s f e r o f l i q u i d p e s t i c i d e s may be r e q u i r e d , ( t h i s i s c u r r e n t l y r e q u i r e d f o r a l l t o x i c i t y Category I l i q u i d s , when s p e c i f i e d on l a b e l s r e g a r d l e s s of t h e t o x i c i t y c a t e g o r y and when s p e c i f i c a l l y r e q u i r e d by r e g u l a t i o n s ) ; (5) change i n t h e p r o d u c t ' s f o r m u l a t i o n may be r e q u i r e d t o reduce excess hazards ( e . g . , reduce d u s t i n e s s ) ; (6) w a t e r - s o l u b l e packaging of the more t o x i c powders may be r e q u i r e d ; (7) minimum f i e l d r e e n t r y i n t e r v a l s may be set by r e g u l a t i o n (a several-month p r o c e s s u n l e s s they are a d e q u a t e l y s p e c i f i e d on the l a b e l ) ; (8) m e d i c a l s u p e r v i s i o n may be r e q u i r e d by r e g u l a t i o n ; and/or (9) d e t a i l e d s a f e t y t r a i n i n g may be r e q u i r e d f o r s p e c i f i c p e s t i c i d e s . EXAMPLE OF VALUE OF BIOLOGIC MONITORING DATA The c u r r e n t common m e t h o d s f o r m e a s u r i n g w o r k e r e x p o s u r e t o p e s t i c i d e s i n v o l v e measurement of d i s l o d g e a b l e f o l i a r r e s i d u e s or r e s i d u e s i n t h e b r e a t h i n g zone and/or on the s k i n . The dermal d e p o s i t i o n d a t a i s then used w i t h dermal a b s o r p t i o n r a t e d a t a c o l l e c t e d i n r o d e n t s o r monkeys t o c a l c u l a t e p r o b a b l e human exposure. U n c e r t a i n t i e s about the b i o a v a i l a b i l i t y and t r a n s f e r of r e s i d u e s i n w o r k e n v i r o n m e n t s may result i n overestimated exposures. Below we have summarized our r e c e n t study o f captan


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exposures o f s t r a w b e r r y h a r v e s t workers t o i l l u s t r a t e some o f these considerations. Introduction. Studies of t h e dermal p e s t i c i d e exposures of s t r a w b e r r y h a r v e s t e r s have been r e p o r t e d by Popendorf e t a l . ( 4 ) , E v e r h a r t and H o l t (5.), Zweig e t a l . (6.), W i n t e r l i n e t a l . (7.) and R i t c e y e t a l . (8.). Some o f t h e d a t a accumulated from s t u d i e s o f s t r a w b e r r y h a r v e s t e r s f i g u r e d p r o m i n e n t l y i n t h e development o f t h e e m p i r i c a l t r a n s f e r c o e f f i c i e n t (commonly c a l l e d t h e Zweig-Popendorf f a c t o r ) o f 5000 cm^/h w h i c h can be used t o r e l a t e d i s l o d g e a b l e f o l i a r p e s t i c i d e r e s i d u e s t o h o u r l y dermal p e s t i c i d e exposures o f f i e l d w o r k e r s (Zweig e t a l . ( 9 ) ) . The t r a n s f e r c o e f f i c i e n t seems t o be a h e l p f u l t o o l t o p r o v i d e a f i r s t e s t i m a t e o f t h e d e r m a l exposure o f f i e l d w o r k e r s engaged i n work t a s k s such as h a r v e s t i n g f r u i t s and v e g e t a b l e s o r p i c k i n g f l o w e r s i n a greenhouse. The t r a n s f e r c o e f f i c i e n t w i l l v a r y d e p e n d i n g on t h e t a s k and u s e s c e n a r i o ( p r o t e c t i v e c l o t h i n g e t c . ) a l t h o u g h s p e c i f i c data about f a c t o r s i n f l u e n c i n g i t are very l i m i t e d . We developed t h r e e e s t i m a t e s o f s t r a w b e r r y h a r v e s t e r exposure t o c a p t a n b a s e d upon d i s l o d g e a b l e f o l i a r r e s i d u e s , d e r m a l d o s i m e t r y , and b i o l o g i c a l m o n i t o r i n g . We w e r e p a r t i c u l a r l y i n t e r e s t e d i n 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 t h e e s t i m a t e s due t o t h e i r c r i t i c a l importance i n t h e r i s k assessment p r o c e s s . A d d i t i o n a l l y , we sought t o measure t h e degree o f m i t i g a t i o n o f t h e captan exposure p r o v i d e d by t h e use o f c h e m i c a l l y - r e s i s t a n t g l o v e s . METHODS; Setting. I n June 1987, we o b t a i n e d t h e c o o p e r a t i o n o f the C a l i f o r n i a S t r a w b e r r y A d v i s o r y Board and Mr. L a r r y G a l p e r , Watsonville, California. The Board p r o v i d e d f i n a n c i a l support t o compensate t h e producer f o r any l o s t time and p r o d u c t i v i t y when we stopped work t o put on measurement d e v i c e s o r t o c o l l e c t samples. We had complete access t o a 72 a c r e s t r a w b e r r y farm w h i c h was c o n s i d e r e d by a l l c o n c e r n e d t o be r e p r e s e n t a t i v e o f t h e a p p r o x i m a t e l y 16,000 a c r e s o f C a l i f o r n i a s t r a w b e r r y p r o d u c t i o n . The s t r a w b e r r y beds were p l a n t e d w i t h 18,500 p l a n t s / a c r e o f e i t h e r t h e P a j a r o and S e l v a v a r i e t i e s . The p l a n t s were grown on e l e v a t e d beds (14") w i t h 52" c e n t e r s . The p l a n t s were w e l l past t h e i r peak p r o d u c t i o n , e.g. 10-12 c r a t e s p e r row a t peak v e r s u s 2-3 c r a t e s p e r row i n J u l y . T h i s p r o v i d e d maximal s e a s o n a l worker c o n t a c t w i t h t r e a t e d f o l i a g e . P r o d u c t i o n d a t a were r e c o r d e d ( c r a t e - 1 0 pounds). Two crews o f workers ( a p p r o x i m a t e l y 35-50 workers/crew) p i c k the f i e l d s t w i c e i n each 6-day week (8 hour days) o f t h e p i c k i n g season which extends from A p r i l t o October. The crews c o n s i s t e d of men and women i n apparent good h e a l t h (85 percent were below age 35) w i t h up t o a maximum of 20 years e x p e r i e n c e as s t r a w b e r r y pickers. They u s u a l l y wear l o n g pants and l o n g - s l e e v e d s h i r t s t o p r o t e c t themselves from t h e g e n e r a l l y c o o l weather o f t h e a r e a where s t r a w b e r r i e s grow w e l l . Some o f t h e men wear s h o r t - s l e e v e d s h i r t s , and o t h e r s r o l l up t h e i r s l e e v e s as t h e mornings warm. Women a d d i t i o n a l l y wear s c a r v e s w h i c h cover most of t h e i r f a c e . A l l o f t h e women and l e s s than 5 percent o f t h e men n o r m a l l y wear c h e m i c a l l y r e s i s t a n t g l o v e s t o p r o t e c t t h e i r hands from d i r t and strawberry j u i c e .


26. MADDY ET AL.


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For t h i s s t u d y , a crew of 40 male v o l u n t e e r s was assembled by the foreman and the r a n c h manager. Males were s e l e c t e d t o p r o v i d e s u f f i c i e n t numbers of workers of one sex t o meet e x p e r i m e n t a l objectives. A d d i t i o n a l l y , because men d i d not u s u a l l y wear g l o v e s they p e r m i t t e d e s t a b l i s h m e n t of glove/no g l o v e groups w i t h o u t r e d u c i n g any worker's normal p r o t e c t i o n . The g l o v e s were 13", c h e m i c a l l y r e s i s t a n t , and made f r o m L o n g S e r v i c e rubber. Exposure d a t a were c o l l e c t e d d u r i n g t h r e e c o n s e c u t i v e days. The a s s i s t a n c e p r o v i d e d by the foreman was c r i t i c a l t o o b t a i n i n g the e n t h u s i a s t i c c o o p e r a t i o n of the p i c k e r s . Throughout the s t u d y , the ranch management served as an e f f e c t i v e l i a i s o n between CDFA s t a f f and the f i e l d w o r k e r s .


t m

Captan Application. Four days b e f o r e h a r v e s t , each p a r t of the f i e l d was t r e a t e d w i t h Captan 50 WP (4 l b s . a . i . / a c r e ) tank mixed w i t h B e n l a t e 50 WP (1 l b a . i . / a c r e ) and Vendex (2 l b s . a . i . / a c r e ) . Captan had not been p r e v i o u s l y used d u r i n g 1987. Two hundred g a l l o n s of spray mix were a p p l i e d t o each a c r e u s i n g a fixed-boom sprayer. S a m p l e s of t a n k m i x were c o l l e c t e d f o r c a p t a n and t e t r a h y d r o p h t h a l i m i d e (THPI), a m e t a b o l i t e of captan, a n a l y s i s . F o l i a r Residue Monitoring. P r i o r t o the captan application and d u r i n g e a c h day o f t h e t h r e e - d a y s t u d y , f o l i a g e s a m p l e s w e r e collected. Each sample c o n s i s t e d of f o r t y 2.54 cm diameter l e a f d i s c s ( B i r k e s t r a n d punch) r e p l i c a t e d t h r e e times b e f o r e and a f t e r harvest. Samples were taken a l o n g a d i a g o n a l l i n e from 10 rows of s t r a w b e r r i e s i n a g i v e n s e c t i o n of the f i e l d . E l e v e n s e c t i o n s of the f i e l d were sampled. The sample j a r s were s e a l e d w i t h aluminum f o i l , capped, and kept on wet i c e u n t i l they were t r a n s p o r t e d t o the l a b o r a t o r y f o r captan r e s i d u e a n a l y s i s . Dermal Dosimetry. Measurements of dermal exposure and e v a l u a t i o n of the p r o t e c t i o n p r o v i d e d by g l o v e s were made on days 2 and 3 of the study. I n o r d e r t o h a v e m i n i m a l e f f e c t s on n o r m a l w o r k p r a c t i c e s and t o a s s u r e t h a t CDFA s t a f f c o u l d a d e q u a t e l y a s s i s t each w o r k e r , the crew was randomly d i v i d e d i n t o two groups of 20 t h a t were m o n i t o r e d f o r one day each. On a g i v e n day each group of 20 was p r o v i d e d w i t h a s e t of 100% c o t t o n , t i g h t f i t t i n g l o n g underwear t o be worn f o r f o u r hours beneath normal w o r k c l o t h e s and w h i c h served as dermal d o s i m e t e r s . Each worker was g i v e n t h e underwear the day b e f o r e t h e i r scheduled m o n i t o r i n g . The group was f u r t h e r d i v i d e d i n t o " g l o v e " and "no g l o v e " subgroups. Dermal exposure was m o n i t o r e d d u r i n g a 4-hour, morning work period. The workers c a r e f u l l y removed t h e d o s i m e t e r s i n temporary change rooms c o n s t r u c t e d i n t h e back of two r e n t a l t r u c k s u s i n g sheets and p l a s t i c p i p e . The garments were p l a c e d i n t o Z i p - l o c k bags and s t o r e d on dry i c e u n t i l p r o c e s s i n g . At t h a t time arm and l e g dosimeter samples were p r e p a r e d , i c e d , and t r a n s p o r t e d t o the laboratory. C o n c u r r e n t l y , handwashes were done on each s u b j e c t u s i n g 400 ml of 1% S u r t e n s o l u t i o n c o n t a i n e d i n a one g a l l o n Z i p - l o c k bag. E a c h p e r s o n w a s h e d t h e i r hands f o r two o n e - m i n u t e p e r i o d s . Handwashes (800 ml) were subsampled (500 ml) and s t o r e d on d r y i c e f o r t r a n s p o r t t o the l a b o r a t o r y .


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D u r i n g the t h r e e day study t h e work p e r i o d was a p p r o x i m a t e l y d i v i d e d i n t o t h r e e 7-hour segments. D u r i n g a 4-hour segment of e i t h e r day two o r t h r e e of the s t u d y , each worker wore g l o v e s and l o n g underwear as a dermal d o s i m e t e r . Thus, exposure p o t e n t i a l s might be reduced by a f a c t o r of 21 - 4/21. No d i r e c t e s t i m a t e s of the amount of exposure o c c u r r i n g d u r i n g the p e r i o d of p a s s i v e d o s i m e t r y a r e a v a i l a b l e and no c o r r e c t i o n s w e r e u s e d t o make exposure e s t i m a t e s . Urine. P i c k e r s were p r o v i d e d t h r e e or f o u r p o l y e t h y l e n e u r i n e c o l l e c t i o n b o t t l e s f o r d a i l y 24-hour c o l l e c t i o n s . The b o t t l e s were h e l d i n i n s u l a t e d boxes i n the f i e l d d u r i n g t h e work day and two unused b o t t l e s were taken home each n i g h t . C r e a t i n i n e l e v e l s were measured i n each 24-hour v o i d at a l o c a l c l i n i c a l l a b o r a t o r y as an i n d i c a t o r of compliance. Extraction. Clean-up and Analysis. D i s l o d g e a b l e captan r e s i d u e s on l e a f samples were p r e p a r e d a c c o r d i n g t o Gunther et a l . ( 1 0 ) . Samples were shaken t h r e e times w i t h S u r t e n s o l u t i o n and e x t r a c t e d t h r e e times w i t h e t h y l a c e t a t e a f t e r a d d i t i o n of Na2S04» After volume r e d u c t i o n the samples were a n a l y z e d by gas chromatography. Captan was a n a l y z e d on the dermal d o s i m e t e r s i n a s i m i l a r fashion. The i n i t i a l e x t r a c t was prepared by s e p a r a t e l y t u m b l i n g i n d i v i d u a l s e t s of underwear arms and l e g s w i t h e t h y l a c e t a t e . Urinary THPI ( c i s - 1 , 2 - d i c a r b o x i m i d o - 4 - c y c l o h e x e n e ) was determined as r e p o r t e d by W i n t e r l i n et a l . (7_) • T w e n t y - f i v e ml a l i q u o t s were e x t r a c t e d w i t h methylene c h l o r i d e , f i l t e r e d , d r i e d , and t a k e n up i n benzene. The e x t r a c t was a n a l y z e d u s i n g H e w l e t t Packard 5880A gas chromatograph w i t h a N/P i o n i z a t i o n d e t e c t o r . The minimum d e t e c t a b l e l e v e l of THPI i n u r i n e was 0.03 ug/ml and r e c o v e r i e s ranged from 80 t o 89 p e r c e n t . Subsequently a set of 10 u r i n e samples from h i g h exposure workers were f u r t h e r a n a l y z e d by Morse L a b o r a t o r y , Sacramento, C.A. A pH 11 c l e a n - u p and n i t r o g e n s p e c i f i c e l e c t r o l y t i c c o n d u c t i v i t y d e t e c t o r were used t o a c h i e v e a minimum 0.005 ppm s e n s i t i v i t y . At 0.02 and 0.01 ppm s e n s i t i v i t y t h e r e c o v e r i e s of THPI were 75 and 67 percent r e s p e c t i v e l y . Statistics. The d i f f e r e n c e s between means (3 r e p l i c a t e s ) p r e - and p o s t - h a r v e s t d i s l o d g e a b l e f o l i a g e r e s i d u e s were compared u s i n g paired t-tests. A randomized b l o c k d e s i g n was used t o i n v e s t i g a t e p o t e n t i a l m i t i g a t i n g e f f e c t s of g l o v e s on dermal captan exposure. F a c t o r s i n c l u d e d i n the l i n e a r model f o r a n a l y s i s i n c l u d e d g l o v e assignment, day, and a g l o v e i n t e r a c t i n g w i t h day term. I f no g l o v e assignment by day i n t e r a c t i o n was determined (P

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