Pesticide Use: The Need for Proper Protection, Application, and

Chapter 11

Pesticide Use: The Need for Proper Protection, Application, and Disposal Downloaded by NORTH CAROLINA STATE UNIV on January 2, 2018 | http://pubs.acs.org Publication Date: March 12, 1987 | doi: 10.1021/bk-1987-0336.ch011

W. K. Hock The Pennsylvania State University, University Park, PA 16802

Current pesticide management practices can result in three categories of human exposure situations--acute, chronic high or occupational, and chronic low or incidental. Pesticide exposure, whether direct or via chemical trespass from treated areas, can be reduced, if not eliminated entirely, by utilizing: (a) adequate personal protective equipment, (b) technologically superior application equipment and techniques, and (c) improved and economically affordable disposal processes. New lightweight and inexpensive protective clothing and equipment need to be developed if applicators are expected to comply with personal protection requirements on pesticide labels. Research in application technology needs to address the issue of applicator exposure as well as that of efficacy and economics, and reliable cost efficient disposal techniques need to be developed for small volume pesticide users. By design,

p e s t i c i d e s a r e b i o l o g i c a l l y a c t i v e a n d , i n most c a s e s , toxic. T h u s , t h e y p o s e p o t e n t i a l r i s k s t o human b e i n g s a n d o t h e r l i v i n g organisms (1). As i s t h e case w i t h t o x i c s u b s t a n c e s i n g e n e r a l , p e s t i c i d e s pose s e v e r a l d i f f e r e n t k i n d s o f t h r e a t s t o health. These a d v e r s e e f f e c t s a r e commonly c o n s i d e r e d as e i t h e r "acute" e f f e c t s , developing q u i c k l y a f t e r exposure but of u s u a l l y s h o r t d u r a t i o n , o r " c h r o n i c " e f f e c t s , w h i c h may a p p e a r a f t e r a d e l a y , o f t e n y e a r s , b u t t h e n p e r s i s t f o r e x t e n d e d p e r i o d s (2^). C h r o n i c adverse e f f e c t s occur as a r e s u l t o f s u s t a i n e d exposures but a r e much more d i f f i c u l t t o e v a l u a t e t h a n a r e a c u t e e f f e c t s ( T a b l e I ) . Such e x p o s u r e s a r e o f t e n c l a s s i f i e d as " c h r o n i c h i g h " r e s u l t i n g from o c c u p a t i o n a l exposures, o r " c h r o n i c low" o c c u r i n g from low l e v e l , i n c i d e n t a l e x p o s u r e (3). We know t h a t t h e r e a r e some c h r o n i c e f f e c t s from p a r t i c u l a r chemicals, b u t s e c u r i n g the documentation f o r p o s s i b l e long-term e f f e c t s such as i n c r e a s e d prevalence r a t e s o f cancer, v a s c u l a r d i s e a s e , and organ i n j u r y i s extremely difficult, a n d may w e l l b e i m p o s s i b l e t o o b t a i n (2^).

0097-6156/87/0336-0128$06.00/0 © 1987 American Chemical Society

Ragsdale and Kuhr; Pesticides ACS Symposium Series; American Chemical Society: Washington, DC, 1987.

11.

HOCK

Downloaded by NORTH CAROLINA STATE UNIV on January 2, 2018 | http://pubs.acs.org Publication Date: March 12, 1987 | doi: 10.1021/bk-1987-0336.ch011

Table

I.

Proper Protection, Application, and Disposal Chronic Adverse E f f e c t s

129

of Pesticides

Chronic effects (delayed onset, or protracted, recurrent, or i r r e v e r s i b l e course) A. Peripheral neuropathy B. E f f e c t s on r e p r o d u c t i o n C. Sensitization D. Suspected, but generally unconfirmed e f f e c t s : 1. E f f e c t s on b r a i n , h e a r t , l i v e r , k i d n e y , l u n g , b l o o d , r e p r o d u c t i v e organs 2. Accelerated atherosclerosis, hypertension 3. Carcinogenesis 4. Teratogenesis 5. Impaired immunity and immunopathies S o u r c e : R e f . 2.

W i t h an e x c e s s i v e , s i n g l e e x p o s u r e , t h e r e s u l t w i l l be e i t h e r a systemic p e s t i c i d e poisoning or a t o p i c a l l e s i o n frequently observed on t h e s k i n o r i n t h e e y e s . S i n c e most a c u t e i n t o x i c a t i o n s a r e f r o m the carbamate and organoposphate i n s e c t i c i d e s , t h e s y s t e m i c manif e s t a t i o n s a r e c h o l i n e r g i c a n d a r e due t o t h e i n h i b i t i o n o f a c e t y l cholinesterase and t h e r e s u l t a n t a c c u m u l a t i o n o f t h e neurot r a n s m i t t e r a c e t y l c h o l i n e , a t the synapse. Topical effects, i n contrast, either are the result of the i r r i t a n t properties ofthe c h e m i c a l s i n t h e f o r m u l a t i o n o r have an a l l e r g e n i c b a s i s f o r t h e i r occurrence (3). However, t o p i c a l e f f e c t s a r e n o t n e c e s s a r i l y e x c l u s i v e l y the r e s u l t of exposure t o the a c t i v e ingredient i n the f o r m u l a t i o n b u t may r e s u l t f r o m a r e a c t i o n t o o n e o r more i n e r t s a s well. With chronic or sustained exposure t o p e s t i c i d e s , the populat i o n s a t r i s k a r e t h o s e who r e c e i v e r e p e t i t i v e e x p o s u r e s d u r i n g t h e manufacture, formulation, mixing, a p p l i c a t i o n , or disposal of p e s t i cides. Another type of chronic exposure i s p e r s i s t e n t residue c o n t a c t by w o r k e r s i n t h e f i e l d d u r i n g t h e h a r v e s t i n g and t h i n n i n g of f r u i t s , v e g e t a b l e s and o t h e r a g r i c u l t u r a l c o m m o d i t i e s . The o u t c o m e o f t h e s e r e p e t i t i v e e x p o s u r e s c a n r e s u l t i n a number o f different diseases. Although of considerable public concern, the chronic incidental e x p o s u r e t h a t t h e g e n e r a l p u b l i c r e c e i v e s from t r a c e amounts o f p e s t i c i d e r e s i d u e s i n a i r , f o o d , and w a t e r , does n o t u s u a l l y r e s u l t in a public health c r i s i s to the population at large. I n such instances a p e s t i c i d e exposure p r o f i l e i s required t o determine the extent and/or s e v e r i t y o f t h i s i n c i d e n t a l , i n v o l u n t a r y pesticide e x p o s u r e (_3). W i t h p e s t i c i d e s b e i n g u s e d c u r r e n t l y a t a r a t e a p p r o a c h i n g one b i l l i o n pounds p e r y e a r i n t h e U n i t e d S t a t e s a l o n e , t h e r i s k s t o a g r i c u l t u r a l workers and t o t h e g e n e r a l p u b l i c a l i k e a r e s i g n i f i c a n t , e s p e c i a l l y i f one c o n s i d e r s t h a t o n l y 1-3% o f a n a g r i c u l t u r a l c h e m i c a l may a c t u a l l y r e a c h t h e i n t e n d e d s i t e o f a c t i o n ( 4 ) . J u s t w h e r e i s t h e o t h e r 97-997o g o i n g ? Clearly, the application of l i q u i d s p r a y s t o some a g r i c u l t u r a l c r o p c a n o p i e s i s a v e r y i n e f f i c i e n t process. U n f o r t u n a t e l y , t h e r e l a t i o n s h i p s between t h e spray p r o c e s s , the t a r g e t p e s t s , and t h e c r o p s themselves a r e v e r y complex and c e r t a i n l y not well understood. The same c a n be s a i d a b o u t t h e


130

PESTICIDES: MINIMIZING THE RISKS

s t a t e of the a r t i n v o l v i n g hazardous waste d i s p o s a l which, of c o u r s e , i n c l u d e s p e s t i c i d e waste management. P e s t i c i d e h a n d l i n g , from i n c e p t i o n i n the t e s t tube to u l t i m a t e d i s p o s a l of wastes by a p p l i c a t o r s i s not w i t h o u t r i s k . . . to the u s e r , to the g e n e r a l p u b l i c , and to the environment. A l l p e s t i c i d e u s e r s and h a n d l e r s need to keep a b r e a s t of c u r r e n t i n n o v a t i o n s i n p e r s o n a l p r o t e c t i v e equipment, a p p l i c a t i o n t e c h n o l o g y and d i s p o s a l t e c h n i q u e s .


Personal Protective

Equipment

P e s t i c i d e s as a c l a s s of c h e m i c a l s are t o x i c . But p e s t i c i d e s need not b p h*7.ardous to the u s e r i f ways can be found to reduce exposure. Whether are d r i v i n g an a u t o m o b i l e , c u t t i n g f i r e w o o d w i t h a power saw, or u s i n g p e s t i c i d e s , the r i s k s or h a z a r d s a s s o c i a t e d w i t h these modern t e c h n o l o g i c a l i n n o v a t i o n s can be s u b s t a n t i a l l y reduced by e f f e c t i v e l y u t i l i z i n g a p p r o p r i a t e r i s k r e d u c t i o n t e c h n i q u e s and p r a c t i c e s . One such p r a c t i c e , at l e a s t w i t h r e g a r d to p e s t i c i d e s , i s to use a l l a p p r o p r i a t e p r o t e c t i v e c l o t h i n g and o t h e r s a f e t y equipment. Such p r o t e c t i v e d e v i c e s can reduce and, i n some i n s t a n c e s , e l i m i n a t e exposure to p e s t i c i d e s a l t o g e t h e r (1) • The type of p r o t e c t i v e c l o t h i n g and equipment needed depends on the job b e i n g done and the type of c h e m i c a l b e i n g used. With some of the more hazardous c h e m i c a l s such equipment i s o f t e n mandatory. As a minimum the f o l l o w i n g p r o t e c t i v e items s h o u l d be a v a i l a b l e when h a n d l i n g p e s t i c i d e s : (1) C l e a n c l o t h i n g , i n c l u d i n g a l o n g - s l e e v e d s h i r t , long t r o u s e r s , and/or c o v e r a l l s or a spray s u i t made of a t i g h t l y woven f a b r i c or a w a t e r - r e p e l l e n t material. (2) Waterproof g l o v e s , u n l i n e d and w i t h o u t a f a b r i c w r i s t band. S h i r t s l e e v e s s h o u l d be worn over g l o v e s i n most i n s t a n c e s , not t u c k e d i n s i d e . (3) Waterproof b o o t s . Pants l e g s s h o u l d be worn over b o o t s , not t u c k e d i n s i d e . (4) Wide-brimmed w a t e r p r o o f h a t . (5) Goggles or f u l l - f a c e d s h i e l d . (6) R e s p i r a t o r w i t h a c l e a n c a r t r i d g e or c a n i s t e r . The c o r r e c t type of c a r t r i d g e or c a n i s t e r must be used f o r the s p e c i f i c c h e m i c a l b e i n g a p p l i e d ; they d i f f e r f o r p a r t i c u l a r k i n d s or groups of t o x i c a n t s . C o n s i d e r a b l e d i f f i c u l t i e s u n f o r t u n a t e l y remain w i t h both the d e s i g n and use of t h e s e p r o t e c t i v e d e v i c e s . The independent farmer who r e g u l a r l y h a n d l e s and a p p l i e s p e s t i c i d e s tends to shy away from u s i n g p r o t e c t i v e garments, o f t e n c o m p l a i n i n g t h a t such c l o t h i n g i s u n c o m f o r t a b l y warm. In hot weather, some types of p r o t e c t i v e c l o t h i n g may a c t u a l l y c o n t r i b u t e to heat e x h a u s t i o n . The same c o m p l a i n t s are o f t e n d i r e c t e d a g a i n s t p e s t i c i d e r e s p i r a t o r y p r o t e c t i v e d e v i c e s as w e l l . U n f o r t u n a t e l y , the p r o t e c t i v e equipment t h a t p r o v i d e s the b e s t p r o t e c t i o n f o r the p e s t i c i d e a p p l i c a t o r i s a l s o u s u a l l y the most u n c o m f o r t a b l e and cumbersome to wear, not t o mention f r e q u e n t l y the most c o s t l y . There are now, however, reasons f o r optimism. Inexpensive d i s p o s a b l e or l i m i t e d - u s e l i g h t w e i g h t c l o t h i n g and a c c e s s o r i e s have now become commonplace i n i n d u s t r y as p e r s o n a l p r o t e c t i v e items;



11.

HOCK

Proper Protection, Application, and Disposal

131

i . e . c o v e r a l l s , c o a t s , s h i r t s , p a n t s , and hoods (5). Spunbonded o l e f i n (Tyvek) i s the most commonly used f a b r i c f o r i n d u s t r i a l d i s p o s a b l e or l i m i t e d - u s e p r o t e c t i v e c l o t h i n g . Such f a b r i c i s made by s p i n n i n g c o n t i n u o u s s t r a n d s of v e r y f i n e , i n t e r c o n n e c t e d p o l y e t h y l e n e f i b e r s , and then bonding them t o g e t h e r w i t h heat and p r e s s u r e (6). The f a b r i c can a l s o be c o a t e d or l a m i n a t e d w i t h a p o l y e t h y l e n e c o a t i n g f o r added p r o t e c t i o n . For example, breakthrough of a methyl p a r a t h i o n f i e l d s p r a y through uncoated Tyvek, p o l y e t h y l e n e - c o a t e d Tyvek, and S a r a n e x - l a m i n a t e d Tyvek f a b r i c s was l e s s than 5 min., 30 t o 45 min., and g r e a t e r then 240 min., r e s p e c t i v e l y ( 7 ) . The c o a t e d / l a m i n a t e d spunbonded o l e f i n f a b r i c i s c l e a r l y an e f f e c t i v e p a r t i c l e b a r r i e r and r e s i s t s l i q u i d s p l a s h p e n e t r a t i o n , p r o p e r t i e s a b s o l u t e l y e s s e n t i a l when a p p l y i n g pesticides. One of the most d e s i r a b l e a t t r i b u t e s of t h i s f a b r i c i s i t s l i g h t w e i g h t p r o p e r t y . A t y p i c a l n o n l a m i n a t e d c o v e r a l l weighs o n l y about f i v e ounces, thus e l i m i n a t i n g o r , a t l e a s t , r e d u c i n g the " f a t i g u e f a c t o r " commonly a s s o c i a t e d w i t h heavy r u b b e r i z e d spray suits. Because of t h e i r s u p e r i o r l i q u i d h o l d - o u t p r o p e r t i e s , d u r a b i l i t y , c o m f o r t , and low c o s t , spunbonded o l e f i n and o t h e r nonwoven f a b r i c s are now b e i n g used w i d e l y i n l i m i t e d use or d i s p o s a b l e p r o t e c t i v e garments. In the f u t u r e , w i t h the development of new f a b r i c s , new c o m b i n a t i o n s , and new s t y l e m o d i f i c a t i o n s , these l i g h t w e i g h t garments w i l l f i n d even wider usage among p e s t i c i d e u s e r s as a way t o minimize o c c u p a t i o n a l exposure. I f p r o t e c t i v e garments can minimize dermal d e p o s i t i o n of c h e m i c a l s , then r e s p i r a t o r y p r o t e c t i v e d e v i c e s can a i d i n r e d u c i n g pulmonary exposure to a i r b o r n e v o l a t i l e s and p a r t i c u l a t e s . As w i t h p r o t e c t i v e garments, the most common excuse f o r not wearing a r e s p i r a t o r when a p p l y i n g p e s t i c i d e s i s c o m f o r t . It i s generally e a s i e r and c e r t a i n l y much more c o m f o r t a b l e not to wear a r e s p i r a t o r . Here a g a i n m a n u f a c t u r e r s must address the comfort f a c t o r i f p e s t i c i d e u s e r s are expected to wear even the most b a s i c a i r p u r i f y i n g d e v i c e , the c h e m i c a l c a r t r i d g e r e s p i r a t o r . Application Whereas p r o t e c t i v e c l o t h i n g and equipment attempt t o reduce a p p l i c a t o r exposure by i n t e r c e p t i n g s p r a y d r o p l e t s or dust p a r t i c l e s p r i o r t o d e p o s i t i o n on the s k i n or t r a n s f e r t o the l u n g s , p e s t i c i d e a p p l i c a t i o n t e c h n o l o g y tends t o f o c u s on improving p e n e t r a t i o n and d e p o s i t i o n of a g r i c h e m i c a l s i n t o c r o p c a n o p i e s o r , i n o t h e r words, r e d u c i n g movement o f f t a r g e t . New p e s t i c i d e a p p l i c a t i o n i n n o v a t i o n s depend on many f a c t o r s , of which s a f e t y i s o n l y one. F a c t o r s such as c o s t , c o n v e n i e n c e , l a b o r time r e q u i r e m e n t s , and, of c o u r s e , e f f i c a c y u s u a l l y take precedence (JO . Few types of a p p l i c a t i o n equipment have been t e s t e d f o r t h e i r exposure impact, and v e r y few of the many combinations of f o r m u l a t i o n s and a c t i v e i n g r e d i e n t s have been t e s t e d w i t h each type of equipment. D u r i n g the p a s t 30 y e a r s t h e r e has been phenomenal p r o g r e s s i n the development of h i g h l y a c t i v e and e f f e c t i v e a g r i c h e m i c a l s , y e t we have not kept pace i n e i t h e r the development of e f f i c i e n t p e s t i c i d e d e l i v e r y systems or i n d e v e l o p i n g a b a s i c u n d e r s t a n d i n g of the components of e f f i c i e n t p e s t i c i d e a p p l i c a t i o n ( 8 ) . I f development indeed l a c k s i n these a r e a s , no wonder then t h a t so l i t t l e r e s e a r c h



132


h a s b e e n d o n e o n how a p p l i c a t i o n m e t h o d s a f f e c t p e s t i c i d e e x p o s u r e levels. A l t h o u g h we a r e w e l l a w a r e t h a t t h e r e i s a n e x p o s u r e p o t e n t i a l f r o m a n y t y p e o f f o r m u l a t i o n , we g e n e r a l l y r e l e g a t e o u r m a j o r concerns t o the l i q u i d o r s p r a y a b l e f o r m u l a t i o n s . When l i q u i d a p p l i c a t i o n i s e s s e n t i a l , t h e f o r m u l a t i o n c a n be m o d i f i e d t o a s s u r e t h a t d r o p l e t s r e m a i n l a r g e e n o u g h t o m i n i m i z e d r i f t (1_). The w o r s t d r i f t problems r e s u l t from the s m a l l e s t , n o n v i s i b l e p a r t i c l e so r d r o p l e t s , g e n e r a l l y t h o s e u n d e r 100 m i c r o n s ( T a b l e I I ) . The s m a l l e r the p a r t i c l e , the g r e a t e r the d r i f t p o t e n t i a l . Table

II.

Particle

Drift

o f an Oil/Water

Diameter 800 400 200 100 50

(microns)

Emulsion

1

Drift Distance Downwind ( F t . ) 25-50 50-100 150-300 500-1,000 Indefinite

2.8 o i l / w a t e r e m u l s i o n a p p l i e d d u r i n g a s t r o n g h e i g h t o f f i v e f e e t and w i n d s p e e d a t 5 MPH.

i n v e r s i o n a t a boom

S p r a y n o z z l e s d e s i g n e d f o r b o t h a i r c r a f t and g r o u n d e q u i p m e n t can a l s o be u s e d t o e n l a r g e d r o p l e t s i z e o f the s p r a y . Application e q u i p m e n t c a n a l s o be m o d i f i e d t o r e d u c e d r i f t . For example, s h r o u d i n g t h e s p r a y booms o f g r o u n d e q u i p m e n t k e e p s d r o p l e t s f r o m s w i r l i n g up i n t o t h e a i r , t h u s r e d u c i n g t h e p o t e n t i a l f o r d r i f t a n d a p p l i c a t o r exposure. A l o o k a t two r e c e n t t e c h n o l o g i c a l i n n o v a t i o n s i n s p r a y i n g systems as w e l l as a c u r r e n t a p p l i c a t i o n p r a c t i c e w i l l b r i n g the issue o f a p p l i c a t o r exposure i n r e l a t i o n t o a p p l i c a t i o n p r a c t i c e s and t e c h n o l o g y i n t o b e t t e r f o c u s . E l e c t r o s t a t i c sprayers p r o p e l charged p e s t i c i d e d r o p l e t s t o the target crop. I n most f i e l d t e s t s , s i g n i f i c a n t l y i m p r o v e d d e p o s i t i o n coupled with a reduction i n d r i f t occurred with charged droplets (9). These d r o p l e t s are p r o p e l l e d a t h i g h v e l o c i t y from the s p r a y n o z z l e t o the t a r g e t and, because t h e y are p o s i t i v e l y c h a r g e d , t h e y are m u t u a l l y r e p e l l e n t t o one a n o t h e r a n d a t t r a c t e d t o the c r o p . A l t h o u g h more e x t e n s i v e a p p l i c a t o r e x p o s u r e s t u d i e s a r e n e e d e d u s i n g e l e c t r o s t a t i c s p r a y e r s , p r e l i m i n a r y r e s u l t s suggest t h a t such e q u i p m e n t i m p r o v e s s a f e t y a s w e l l (1) ( T a b l e I I I ) . S i g n i f i c a n t l y i m p r o v e d d e p o s i t i o n a s s o c i a t e d w i t h t h e s e s p r a y e r s means more c h e m i c a l i s d e p o s i t e d on the t a r g e t p l a n t (and p o s s i b l y a d j a c e n t s o i l s ) w i t h l e s s t o d r i f t i n t h e e n v i r o n m e n t and p r e s u m a b l y l e s s d e p o s i t i o n on the a p p l i c a t o r . A n o t h e r new m e t h o d o f s p r a y a p p l i c a t i o n w h i c h may i m p r o v e f o l i a r d e p o s i t i o n i s c a l l e d a i r - a s s i s t s p r a y i n g (1^0). This a p p l i c a t i o n system i n v o l v e s s p r a y i n g a i r along w i t h the p e s t i c i d e t o enhance p e n e t r a t i o n o f crop c a n o p i e s . W i t h more s p r a y i m p a c t i n g the p l a n t , not o n l y i s e n v i r o n m e n t a l impact r e d u c e d but the p e r f o r m a n c e of i n s e c t i c i d e s , f u n g i c i d e s , f o l i a r f e r t i l i z e r s , and growth r e g u l a t o r s i s v a s t l y improved. The new a i r - a s s i s t s y s t e m h a s b e e n shown t o i m p r o v e o v e r a l l



III.

Exposure

Device

Applicator

Tanzania

1

Grams active applied per hour 16 116 21.6 23.4 6.6 13.1 Sprayer: Worker

Crop height (cm) 30-60 30-60 120-160 110-180 66-125 75-180

Sprayers

26.9 369.9 8.9 17.8 3.0 29.5

TDC* mg/hr

TDC* as % o f active ingredient applied 0.17 0.32 0.04 0.08 0.05 0.22

H a z a r d ,," I C I P l a n t P r o t e c t i o n D i v i s i o n

Cypermethrin Cypermethrin Cypermethrin Cypermethrin Cypermethrin Cypermethrin

Formulation

U s i n g C o n v e n t i o n a l and E l e c t r o s t a t i c

Electrodyn sprayer Spinning disc Electrodyn sprayer I v o r y Coast Spinning disc Electrodyn sprayer Paraguay Knapsack * T D C — T o t a l dermal c o n t a m i n a t i o n S o u r c e : T. B . H a r t , "The H a n d - H e l d ' E l e c t r o d y n (Fernhurst, England: undated).

Country

Table



134


coverage of c h e m i c a l s on c r o p f o l i a g e by 234 p e r c e n t on soybeans and 100 p e r c e n t on c o r n . The a i r - a s s i s t s p r a y e r uses f a n n o z z l e s to produce the s p r a y . About 8 i n c h e s beyond the n o z z l e the spray mixes w i t h s w i r l i n g a i r g e n e r a t e d by a c e n t r i f u g a l f a n to form a m i s t around the t a r g e t p l a n t . These a c c e l e r a t e d d r o p l e t s e n t e r the t a r g e t a r e a of the p l a n t and are d e p o s i t e d where d i r e c t e d . Aira s s i s t s p r a y i n g can a l s o be done i n s i d e a metal shroud, g i v i n g good s p r a y s a t u r a t i o n p l u s spray r e c i r c u l a t i o n . Spray d r o p l e t s g e n e r a t e d by a i r - a s s i s t s p r a y e r s are o b v i o u s l y b e t t e r a b l e to p e n e t r a t e dense c a n o p i e s of f o l i a g e because of a c c e l e r a t e d d r o p l e t v e l o c i t y . But does t h i s added s p r a y momentum a l s o i n c r e a s e t o p i c a l and i n h a l a t i o n exposure f o r a p p l i c a t o r s ? The exposure i s s u e w i t h t h i s new t e c h n o l o g y has not been a d e q u a t e l y a d d r e s s e d , yet must be examined b e f o r e t h i s or any new spray system can be c l a s s i f i e d as an u n q u a l i f i e d s u c c e s s . A p o p u l a r c u r r e n t p r a c t i c e i s the use of v e g e t a b l e o i l s as c a r r i e r s i n the a p p l i c a t i o n of c r o p p e s t i c i d e s . As long as the p r o d u c t l a b e l s p e c i f i c a l l y i n c l u d e s i n s t r u c t i o n s t h a t p e r m i t the use of v e g e t a b l e o i l s , such as c o t t o n s e e d and soybean o i l s , as d i l u e n t s or c a r r i e r s i n p l a c e of water, i t i s p e r f e c t l y a c c e p t a b l e to use the p e s t i c i d e i n t h i s manner. T h i s a p p l i e s to d i l u e n t s used i n conventional, low volume, and u l t r a - l o w volume a p p l i c a t i o n s . As t h i s p r a c t i c e r a p i d l y i n c r e a s e d , EPA e x p r e s s e d c o n c e r n s about the p r a c t i c e r e l e v a n t to a p p l i c a t o r / f a r m worker s a f e t y (1^1). The use of v e g e t a b l e o i l s as spray d i l u e n t s / c a r r i e r s might r e s u l t i n c h e m i c a l r e s i d u e s on c r o p s i n excess of p e r m i s s i b l e amounts as w e l l as i n c r e a s e farmworker exposure t o the p e s t i c i d e s when h a n d l i n g t r e a t e d crops. EPA o f f i c i a l s noted t h a t v e g e t a b l e o i l s e v a p o r a t e more s l o w l y than water, and t h e r e are l o n g e r - l a s t i n g r e s i d u e s a f t e r the m a t e r i a l s have been a p p l i e d . The o i l may a l s o i n c r e a s e the human body's a b s o r p t i o n r a t e of the a c t i v e i n g r e d i e n t , f u r t h e r prompting worker s a f e t y c o n c e r n s . In response to these c o n c e r n s , the O f f i c e of P e s t i c i d e s and T o x i c S u b s t a n c e s , EPA, i s s u e d FIFRA Compliance M o n i t o r i n g P o l i c y No. 12.5 on F e b r u a r y 27, 1984 (11_), which i n summary s t a t e s t h a t i n such i n s t a n c e s where no d i l u e n t i s s p e c i f i e d on the l a b e l , water must be used as the d i l u e n t . C l e a r l y , t h i s response was prompted by h e a l t h and s a f e t y c o n c e r n s f o r p e s t i c i d e a p p l i c a t o r s and farmworkers. P e s t i c i d e Waste

Disposal

The i s s u e of p e s t i c i d e waste d i s p o s a l has been r e c o g n i z e d as a n a t i o n a l problem f o r y e a r s , yet today remains as one of the foremost problems c o n f r o n t i n g most p e s t i c i d e u s e r s . In any E x t e n s i o n meeting t h a t a d d r e s s e s p e s t i c i d e s a f e t y i s s u e s , the most f r e q u e n t l y d i s c u s s e d t o p i c i s t h a t of p e s t i c i d e waste d i s p o s a l . The u n d i s p u t a b l e f a c t i s t h a t adequate hazardous waste d i s p o s a l f a c i l i t i e s do not p r e s e n t l y e x i s t f o r s m a l l volume p e s t i c i d e u s e r s . Improper, a l b e i t not n e c e s s a r i l y i r r e s p o n s i b l e , h a n d l i n g of p e s t i c i d e wastes and c o n t a i n e r s o f t e n r e s u l t s i n u n a c c e p t a b l e l e v e l s of e n v i r o n m e n t a l c o n t a m i n a t i o n and e x c e s s i v e exposure to the a p p l i c a t o r s themselves. P e s t i c i d e waste d i s p o s a l p o l i c y and p r a c t i c e s have been d e a l t w i t h r e c e n t l y by t h r e e n a t i o n a l workshops (1^2, 13, V£). These c o n f e r e n c e s d e f i n e d the problem and examined the s t a t e - o f - t h e - a r t



11.

HOCK


135

t e c h n o l o g y f o r p e s t i c i d e waste d i s p o s a l . The s o u r c e s of p o t e n t i a l problems i n c l u d e the c o n t a i n e r s ; unwanted, unuseable and u n i d e n t i f i a b l e p r o d u c t s ; tank r i n s e w a t e r s ; l e f t o v e r m a t e r i a l s ; equipment wash waters; i n c o m p a t i b l e m i x t u r e s ; s p i l l e d m a t e r i a l s from a c c i d e n t s ; stormwater and r u n - o f f from n a t u r a l o c c u r r e n c e s ; and t o x i c d e b r i s from f i r e s (15). D e f i n i n g the problem i s r e l a t i v e l y easy; i t ' s the s o l u t i o n s t h a t are so d i f f i c u l t to d e v e l o p . Speakers a t these n a t i o n a l workshops d e s c r i b e d c o n t a i n e r c o l l e c t i o n programs and v a r i o u s t e c h n i q u e s f o r waste treatment and disposal. Much of the d i s c u s s i o n was devoted to p i o n e e r i n g e f f o r t s t o d e a l w i t h d i s p o s a l problems. For the most p a r t , however, the i s s u e s of e n v i r o n m e n t a l and human h e a l t h concerns were not addressed. Of the dozen t e c h n o l o g i e s t h a t are b e i n g i n v e s t i g a t e d f o r d i s p o s i n g of p e s t i c i d e wastewater, o n l y f o u r methods are c u r r e n t l y a v a i l a b l e c o m m e r c i a l l y (13, 1^6) ( T a b l e I V ) . But, the q u e s t i o n must be asked, a v a i l a b l e to whom? O f t e n even the s i m p l i e s t t e c h n o l o g y i s not p r i c e d i n the range t h a t farmers and s m a l l commercial a p p l i c a t o r s can a f f o r d . R e c y c l i n g p e s t i c i d e r i n s e w a t e r seems to be a wastewater management system t h a t c o u l d be a v a i l a b l e to most p e s t i c i d e u s e r s . The b a s i c d e s i g n of a wastewater c o l l e c t i o n / r e c y c l i n g system i n c l u d e s a wash pad and some type of r e c e p t a c l e f o r r i n s e w a t e r containment. The r i n s e w a t e r s can then be mixed as needed i n t o subsequent s p r a y s o l u t i o n s as an a l t e r n a t i v e t o treatment or disposal. However, t h i s p r a c t i c e does e l i c i t some concerns e s p e c i a l l y where more d i v e r s e and s e n s i t i v e s p e c i a l t y c r o p s are grown. The main concerns a r i s e from tank m i x i n g of p e s t i c i d e s not l a b e l e d f o r such use, p h y t o t o x i c i t y to some c r o p s , and r e s i d u e s i n excess of e s t a b l i s h e d t o l e r a n c e s (17). The p o t e n t i a l f o r e x c e s s i v e a p p l i c a t o r exposure must a l s o be viewed as a s i g n i f i c a n t c o n c e r n because the r i n s e w a t e r s , l a d e n w i t h these c h e m i c a l s , are used much the same as tap water i s used f o r m i x i n g c h e m i c a l s i n a spray tank. T h i s p r e s e n t s an a d d i t i o n a l exposure r i s k to the a p p l i c a t o r e v e r y time the r i n s e w a t e r i s handled d u r i n g the r e c y c l i n g p r o c e s s . C l o s e d system t e c h n o l o g y f o r t r a n s f e r r i n g p e s t i c i d e c o n c e n t r a t e s i n t o a spray tank i s d e s i g n e d to empty s h i p p i n g c o n t a i n e r s of l i q u i d p e s t i c i d e s , r i n s e these c o n t a i n e r s , and t r a n s f e r b o t h p r o d u c t and r i n s a t e to the a p p l i c a t i o n equipment w h i l e e f f e c t i v e l y r e d u c i n g a p p l i c a t o r exposure by m i n i m i z i n g s p i l l i n g and s p l a s h i n g of p e s t i c i d e c o n c e n t r a t e s d u r i n g m i x i n g and a p p l i c a t i o n . P o s s i b l y a m o d i f i e d type of " c l o s e d system" would be a p p r o p r i a t e f o r s t o r i n g and u l t i m a t e l y r e c y c l i n g p e s t i c i d e - c o n t a m i n a t e d r i n s e w a t e r to the spray tank. Such h a n d l i n g and s t o r a g e t e c h n i q u e s would c e r t a i n l y reduce the p o t e n t i a l f o r a p p l i c a t o r exposure. Aboveground s o i l d i s p o s a l beds may u l t i m a t e l y p r o v i d e an e n v i r o n m e n t a l l y s a f e and economical means of d i s p o s i n g of p e s t i c i d e contaminated r i n s e w a t e r (18). R i n s e w a t e r would be c o l l e c t e d i n i t i a l l y i n a sump and pumped i n t o a s p e c i a l l y d e s i g n e d tank w i t h a lower l i q u i d s t o r a g e c o n t a i n e r and an upper l a y e r of s o i l suspended on a p e r f o r a t e d p l a t f o r m . A sump pump would be used to a p p l y d a i l y doses of the accumulated l i q u i d to the s o i l s u r f a c e v i a a s u r f a c e d i s t r i b u t i o n system. A l t h o u g h i t remains to be seen i f these aboveground s o i l d i g e s t i o n systems w i l l be p r a c t i c a l l y f u n c t i o n a l , i t i s i n t e r e s t i n g to observe t h a t such a system t h a t i n c l u d e s wastewater



136


Table

IV.

C a t e g o r i z a t i o n of P e s t i c i d e Wastewater D i s p o s a l Technologies

Technolo; Physical/Chemical Treatment & R e c y c l i n g 1. P e s t i c i d e R i n s e w a t e r Recycling 2. G r a n u l a r C a r b o n Adsorption 3. U V - O z o n a t i o n 4. S m a l l - S c a l e Incineration 5. S o l a r P h o t o Decomposition 6. C h e m i c a l Degradation B i o l o g i c a l Treatment & Land A p p l i c a t i o n 1. E v a p o r a t i o n , P h o t o degradation & Biodegradation i n Containment Devices 2. G e n e t i c a l l y E n g i n e e r e d Products 3. L e a c h F i e l d s 4. A c i d & A l k a l i n e Trickling Filter Systems 5. O r g a n i c M a t r i x Adsorption & Microbial Degradation 6. E v a p o r a t i o n & B i o l o g i c a l Treatment w i t h Wicks

Proven Technology

Technology i s c u r r e n t l y being u t i l i z e d t r e a t and d i s p o s e o f d i l u t e p e s t i c i d e

Category Technology2 Transfer

on a c o m m e r c i a l wastewater.

Emerging ^ Technology

basis to

2 Technology i s being u t i l i z e d commercially t o t r e a t other types of waste and o f f e r s p r o m i s i n g o p p o r t u n i t i e s f o r p e s t i c i d e wastewater. 3 Technology i s not being u t i l i z e d data i n d i c a t e s i ti s a promising pesticide wastewater.

commercially but experimental candidate technology f o r



11. HOCK


137

collection and storage capabilities as well as automatic transfer of the liquid waste to a digester would also reduce direct applicator exposure significantly. At the January 1985 workshop in Denver, O.R. Ehart said, "Although this conference has dwelt upon the regulation of pesticide waste disposal, it is shortsighted not to recognize that the purpose of these regulations is not, or at least should not be, to regulate pesticide waste per se but to protect the environment" (1_9). The term environment as used in this sense most certainly also includes persons who are subject to pesticide contamination through occupational exposure as well as persons who are exposed inadvertently through incidental exposure such as might occur through contact with contaminated potable water sources. Affordable, innovative technology to remedy the pesticide disposal dilemma will, with time, be available to the farmer and other pesticide users. However, as with any new information or technology, the focus will have to be on education if such technical innovations are to be used in an efficacious and responsible manner. Any program on pesticide waste management must also include information on minimizing the risks to the applicator as well as to the environment. Nothing less will be acceptable. Summary EPA's guidelines do not presently address the issue of measuring direct exposure to pesticide applicators (20). Rather, the Agency often takes the "surrogate chemical approach," which uses data from one compound to set exposure standards for another. The problem arising from this kind of approach is that such procedures often fail to provide us information about the permeability properties of the compounds. The EPA needs to develop a standard methodology for assessing applicator exposure and issue relevant guidelines to address the problem. Pesticide manufacturers and user industries need to place greater emphasis on health surveillance programs for their employees. Research programs need to be expanded and coordinated on assessing exposure to pesticides. While the work on exposure should be conducted by pesticide manufacturers, university-based agricultural scientists, and research-oriented governmental agencies, it still remains the responsibility of those agencies concerned with occupational safety and health to take the overall responsibility for establishing research guidelines and coordinating research objectives. However, to accomplish these objectives, the overall research climate and support for such programs need to improve rather dramatically in the immediate future. Literature Cited 1. 2. 3.

Dover, M. J. "A Better Mousetrap: Improving Pest Management for Agriculture"; World Resources Institute: Washington, D. C., 1985; p. 84. Morgan, D. P. In "Residue Reviews"; Gunther, F. A., Ed,; Springer-Verlag: New York, 1980; Vol. 75, pp. 97-102. Davies, J. E. In "Determination and Assessment of Pesticide Exposure"; Siewierski, M., Ed.; Studies in Environmental Science No. 24, Elsevier: New York, 1984; pp. 67-77. Ragsdale and Kuhr; Pesticides ACS Symposium Series; American Chemical Society: Washington, DC, 1987.

138 4. 5. 6. 7.


8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.


Hall, F. R.; et. al. In "Improving Agrochemical and Fertilizer Application Technology"; Hall, F. R., Ed.; Agricultural Research Institute: Bethesda, MD, 1985; pp. 15-23. Goldstein, L. Natl. Safety News 1980, 50-1. "The Properties and Processing of TYVEK Spunbonded Olefin," DuPont Tech. Inf. Bull. S-10, 1973. Schwope, A. D. "The Effectiveness of TYVEK and TYVEK Composites as Barriers to Methyl Parathion," Arthur D. Little, Inc., 1980. Bukovac, M. J. In "Improving Agrochemical and Fertilizer Application Technology"; Hall, F. R., Ed.; Agricultural Research Institute: Bethesda, MD, 1985; pp. 25-38. Matthews, G. A. In "Improving Agrochemical and Fertilizer Application Tehnology"; Hall, F. R., Ed.; Agricultural Research Institute: Bethesda, MD, 1985; pp. 39-52. Richardson, L. Agrichemical Age 1985, 29(9), 8-9, 12. "The Use of a Diluent Not Specified on the Product Label," FIFRA Compliance Monitoring Policy No. 12.5, U.S. EPA, 1984. National Workshop on Pesticide Waste Disposal: Denver, CO; Jan. 28-29, 1985. Pesticide Wastewater Research Workshop: Cincinnati, OH; July 30-31, 1985. National Workshop on Pesticide Waste Disposal: Denver, CO; Jan. 27-29, 1986. Ehart, O. R. Proc. Natl. Workshop on Pesticide Waste Disposal, 1985, pp. 2-11. Bridges, J. S.; C. R. Dempsey. "Proceedings: Research Workshop on the Treatment/Disposal of Pesticide Wastewater"; U.S. EPA: Cincinnati, OH, Jan. 1986; p. 55. Taylor, A. G. Abstr., Pesticide Wastewater Research Workshop: Cincinnati, OH; July 30-31, 1985. Brown, K. W. Agrichemical Age 1986, 30(1), 14, 44. Ehart, O. R. Proc. Natl. Workshop on Pesticide Waste Disposal, 1985, pp. 120-3. Wasserstrom, R. F.; Wiles, R. "Field Duty: U.S. Farmworkers and Pesticide Safety"; World Resources Institute; Washington, D. C., 1985; p. 78.

RECEIVED

September 19, 1986


Pesticide Use: The Need for Proper Protection, Application, and

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