Subterranean Termite Control: Chlordane Residues in Soil

18 Subterranean Termite Control: Chlordane Residues in Soil Surrounding and A i r Within Houses

Downloaded by UNIV OF ROCHESTER on January 19, 2018 | http://pubs.acs.org Publication Date: February 25, 1985 | doi: 10.1021/bk-1985-0273.ch018

R. B . L E I D Y , C . G. W R I G H T , Η . Ε. DUPREE, J R . , and T. J. S H E E T S Pesticide Residue Research Laboratory and Department of Entomology, North Carolina State University, Raleigh, NC 27695

A study was undertaken to determine concentrations of chlordane in soils and the air of houses treated for subterranean termite control by commercial applicators over a 5-year period. Sixty houses, each with known histories of chlordane application were divided into two groups; one from predominately sandy regions and the other from predominately clay-soil regions of North Carolina. The houses were divided further into those with a crawl space (15/region), those with a combination crawl space and slab (15 on clay soils), and those on a full slab (15 on sandy soils). Chlordane residues averaged 1052 and 1475 ppm in sandy and clay soils, respectively; air samples from crawl spaces averaged 14 and 12 µg/m from sand and clay regions, respectively. In the sandy region air samples from kitchens averaged 2.5 (range: 0.05 to 5.7) and those from bedrooms averaged 3.1 (range of 0.05 to 7.2) µg/m . In the clay region average levels in air were 3.0 (range of 0.05 to 9.9) and 3.2 (range of 0.05 to 9.8) µg/m3, for kitchens and bedrooms, respectively. 3

3

F i e l d e x p e r i m e n t s to determine the e f f i c i e n c y of c h l o r d a n e ( 1 , 2 , 4 , 5 , 6 , 7 , 8 , 8 - o c t a c h l o r o - 3 a , 4 , 7 , 7 a - h e x a h y d r o - 4 , 7 - m e t h a n o - l H - i n d e n e ) to c o n t r o l s u b t e r r a n e a n t e r m i t e s have been conducted s i n c e the 1 9 4 0 ' s (JL) , ( 2 ) . T h i s i n s e c t i c i d e c o n t i n u e s to be used w i d e l y today by commercial p e s t - c o n t r o l f i r m s i n houses and i n i n d u s t r i a l b u i l d i n g s . In many i n s t a n c e s , c h l o r d a n e i s a p p l i e d w i t h h e p t a c h l o r ( 1 , 4 , 5 , 6 , 7 , 8 , 8 - h e p t a c h l o r o - 3 a , 4 , 7 , 7 a - t e t r a h y d r o - 4 , 7 - m e t h a n o - l H - i n d e n e ) as a p r e v e n t a t i v e and r e m e d i a l treatment i n b u i l d i n g s . This combination, c a l l e d Termide ( E P A Reg. No. 8 7 6 - 2 3 3 A A c o n t a i n s 3 9 . 2 2 7 chlordane and 1 9 . 6 0 7 o h e p t a c h l o r ) c o n t a i n s 0 . 5 7 o t e c h n i c a l c h l o r d a n e and 0 . 2 5 7 h e p t a c h l o r when d i l u t e d f o r a p p l i c a t i o n . C h l o r d a n e i s a p p l i e d at a 1 . 0 7 o e m u l s i o n w i t h water as the d i l u e n t . R e l a t i v e l y large q u a n t i t i e s ( c a . 3 7 8 - 7 5 6 l i t e r s ) a r e a p p l i e d i n t r e n c h e s dug i n t o s o i l around c r a w l - s p a c e w a l l s and chimney bases and i n t o p i l a s t e r s and w a l l voids. In a d d i t i o n many s t r u c t u r e s b u i l t on c o n c r e t e s l a b s a r e t r e a t e d b e f o r e the f o u n d a t i o n i s p o u r e d . Because of the p e r s i s t e n t 0

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0097-6156/85/0273-0265$06.00/0 © 1985 A m e r i c a n C h e m i c a l Society

Honeycutt et al.; Dermal Exposure Related to Pesticide Use ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

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n a t u r e of these two i n s e c t i c i d e s , and the l a r g e q u a n t i t i e s a p p l i e d , one would expect t o f i n d r e s i d u e s i n s o i l and the ambient a i r o f the treated structures. In an e a r l y study, the c h l o r d a n e l e v e l i n the a i r of f i v e t r e a t e d houses was below the d e t e c t a b l e l e v e l s ( 3 ) . An i n a d v e r t e n t a p p l i c a t i o n at a US a i r - f o r c e (USAF) base caused c h l o r d a n e t o be d i s p e r s e d throughout a house when the f u r n a c e was a c t i v a t e d ( 4 ) . S i m i l a r i n c i d e n t s were r e p o r t e d i n o t h e r base houses, which l e d t o a l a r g e scale, sampling at s e v e r a l USAF b a s e s . Some 500 g r o u n d - l e v e l apartments were sampled at a midwest base i n 1980 and c h l o r d a n e was found i n the a i r at c o n c e n t r a t i o n s up t o 379 Mg/nP (.5)· Seven USAF bases were examined d u r i n g the w i n t e r of 1980-81, and i n 408 u n i t s (86%) of 474 which had been t r e a t e d w i t h c h l o r d a n e u s i n g s u b s l a b i n j e c t i o n o r e x t e r i o r d i t c h i n g a f t e r c o n s t r u c t i o n , the a i r b o r n e c h l o r d a n e c o n c e n t r a t i o n s were l e s s than 3.5 yg/m3. The l e v e l s i n 2% of the u n i t s were g r e a t e r than 6.5 pg/m^. The c h l o r d a n e i n the o t h e r 127 of the houses f e l l between these two l e v e l s ( 6 ) . Wright and L e i d y (7) determined c h l o r d a n e and h e p t a c h l o r l e v e l s i n a i r f o r one y e a r f o l l o w i n g a p r e s c r i b e d a p p l i c a t i o n t o s i x s i n g l e - f l a m i l y houses by commercial pest c o n t r o l f i r m s . Residues of c h l o r d a n e v a r i e d w i d e l y between 0.3 and 5.8 yg/m^, and h e p t a c h l o r r e s i d u e s v a r i e d between 0.01 and 1.8 \ig/rv?. Because r e s i d u e l e v e l s v a r i e d , i t was c o n c l u d e d t h a t a number of f a c t o r s i n c l u d i n g cons t r u c t i o n t y p e , temperature, h u m i d i t y , and a i r movement due t o c o o l i n g and h e a t i n g p r o b a b l y i n f l u e n c e d the c o n c e n t r a t i o n s . There are no e s t a b l i s h e d t o l e r a n c e s f o r c h l o r d a n e o r h e p t a c h l o r i n the ambient a i r i n home environments. An i n t e r i m g u i d e l i n e l e v e l of 5.0 pg/nP ( c h l o r d a n e ) and 2.0 yg/m^ ( h e p t a c h l o r ) has been recommended by the Committee on t o x i c o l o g y of the N a t i o n a l Academy of S c i e n c e s (8). The maximum a l l o w a b l e l i m i t i n work-space a i r d u r i n g a 40 h workweek ( T h r e s h o l d L i m i t V a l u e , Time Weighted Average) (TLV-TWA) i s 500 yg/m^ f o r c h l o r d a n e and h e p t a c h l o r ( 9 ) . Few data are a v a i l a b l e on s o i l and a i r b o r n e r e s i d u e s of c h l o r dane and h e p t a c h l o r from homes t r e a t e d by commercial p e s t c o n t r o l firms. Thus, a study was undertaken t o determine c h l o r d a n e and h e p t a c h l o r r e s i d u e s i n c l a y and sand s o i l s and i n the a i r of s e l e c t e d houses. 0

M a t e r i a l s and Methods House S e l e c t i o n and Sampling P r o c e d u r e . S i x t y s i n g l e - f a m i l y houses were s e l e c t e d by commercial p e s t c o n t r o l f i r m s l o c a t e d i n N o r t h Carolina. The f o l l o w i n g c r i t e r i a were r e q u i r e d f o r s e l e c t i o n : a w i l l i n g n e s s of the homeowner t o a l l o w both s o i l sampling and a i r m o n i t o r i n g ; and e i t h e r a r e m e d i a l or p r e v e n t a t i v e treatment f o r t e r m i t e s w i t h i n the l a s t 5 y e a r s (1978-1983) and e i t h e r c h l o r d a n e or Termide as the t e r m i t i c d e used. Houses were d i v i d e d i n t o two groups: 30 i n the C o a s t a l P l a i n of N o r t h C a r o l i n a w i t h p r e d o m i n a t e l y sandy s o i l s , and 30 i n the Piedmont r e g i o n w i t h p r e d o m i n a t e l y c l a y s o i l s . In the s a n d y - s o i l r e g i o n , 15 houses h a v i n g a f u l l c o n c r e t e s l a b and 15 h a v i n g c r a w l - s p a c e c o n s t r u c t i o n were s e l e c t e d ; i n c l a y - s o i l r e g i o n s , 15 houses w i t h a c o m b i n a t i o n c r a w l s p a c e / s l a b ( i . e . s p l i t l e v e l ) and 15 w i t h c r a w l - s p a c e c o n s t r u c t i o n were chosen. No o b s e r v a t i o n s were made of the a p p l i c a t i o n , because a l l had been completed at the time of s e l e c t i o n ; thus i t was assumed t h a t



18.

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LEIDY ET AL.

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Chlordane

Residues

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the p r o p e r amount o f e i t h e r c h l o r d a n e o r Termide was a p p l i e d following prescribed label directions. The amounts o f t e r m i t i c i d e s a p p l i e d were o b t a i n e d from r e c o r d s o f the p e s t c o n t r o l f i r m t h a t t r e a t e d the house. Temperatures and r e l a t i v e h u m i d i t i e s were meas u r e d i n each house d u r i n g sampling, and a s o i l temperature was taken from houses w i t h c r a w l spaces. In a d d i t i o n , o b s e r v a t i o n s were made as t o whether a i r c o n d i t i o n i n g fans were o p e r a t i n g o r i f windows were open. Composite s o i l samples were taken from a l l houses w i t h c r a w l spaces. Sampling s i t e s around each house were s e l e c t e d based upon the type o f s t r u c t u r e which determines the method o f a p p l i c a t i o n . U s i n g a c o r i n g d e v i c e (30 by 2.5 cm), samples were taken from two l o c a t i o n s a l o n g each o f the f o u r l o n g e s t f o u n d a t i o n w a l l s and from s o i l s around the base o f two p i l l a r s i n the c r a w l space a r e a . An attempt was made t o o b t a i n samples from 0 t o 10 cm and 10 t o 20 cm depths, but i n some i n s t a n c e s the l o c a t i o n s o f the f o u n d a t i o n f o o t i n g i n t e r f e r e d w i t h sampling a t the 10 t o 20 cm depth. S o i l s were p l a c e d i n 950 mL g l a s s j a r s . The j a r s were s e a l e d , and s t o r e d a t -20C u n t i l analyzed. A i r samples were taken i n a c e n t r a l l o c a t i o n o f the c r a w l space, the k i t c h e n , and a bedroom w i t h p e r s o n a l - t y p e a i r samplers ( 1 0 ) . P o l y u r e t h a n e foam p l u g s (2 cm od. by 3 cm) c o n t a i n e d i n a g l a s s h o l d e r were a t t a c h e d t o the sampler. A 2-h sample was taken a t a flow r a t e o f 2.8 L o f a i r / m i n . The h o l d e r and foam were removed, p l a c e d i n p l a s t i c bags, and s t o r e d a t -20C u n t i l a n a l y z e d . S o i l P a r t i c l e - S i z e A n a l y s i s . The hydrometer method was used form a m e c h a n i c a l a n a l y s i s o f the s o i l s ( 1 1 ) .

to per-

A n a l y t i c a l Procedures. S o i l samples were e x t r a c t e d u s i n g a m o d i f i e d p r o c e d u r e d e s c r i b e d by Bennett e t a l ( L 2 ) . S o i l s were s c r e e n e d through a No. 10 mesh s i e v e t o remove r o c k s and d e b r i s . Two grams of s o i l were t a r e d i n t o a 500-mL g l a s s j a r , 5 mL o f d e i o n i z e d water and 50 mL o f 2-propanol were added, and t h e sample was shaken m e c h a n i c a l l y f o r 15 min. One hundred mL o f hexane were added, and the sample was shaken f o r an a d d i t i o n a l 2 h and a l l o w e d t o s i t o v e r night. Samples were f i l t e r e d under reduced p r e s s u r e through a 300-mL membrane f i l t e r apparatus c o n t a i n i n g a GF/B f i b e r g l a s s f i l t e r (4.7 cm o.d.) topped w i t h 10 g Na2S04 (ANHYD) d 5 g Celite. The f i l t r a t e was p l a c e d i n a 500-mL s e p a r a t o r y f u n n e l , 200 mL o f d e i o n i z e d water added, and the c o n t e n t s were shaken g e n t l y f o r 1 min. A f t e r the l a y e r s s e p a r a t e d , the aqueous l a y e r was d i s c a r d e d and the p r o c e d u r e was r e p e a t e d twice more. The hexane l a y e r was f i l t e r e d through Na2S04 (ANHYD) * c o n c e n t r a t e d t o 2 t o 3 mL under reduced p r e s s u r e at 40C. Samples were brought t o f i n a l volume w i t h hexane f o r analysis. A i r samples were e x t r a c t e d as d e s c r i b e d by L e i d y e t a l . , ( 1 3 ) . Foam p l u g s were p l a c e d i n a 250-mL beaker c o n t a i n i n g 150 mL o f e t h y l a c e t a t e , and an a d d i t i o n a l 50 mL of e t h y l a c e t a t e were poured through the g l a s s sample h o l d e r . The p l u g was squeezed a g a i n s t the s i d e o f the beaker u s i n g a 20-cm g l a s s r o d a t 10 min i n t e r v a l s f o r 30 min. The s o l v e n t was poured i n t o a 500-mL b o i l i n g f l a s k and the beaker and foam p l u g were r i n s e d w i t h an a d d i t i o n a l 50 mL o f e t h y l acetate. The combined e x t r a c t was c o n c e n t r a t e d under reduced p r e s s u r e t o 2 t o 3 mL and d i l u t e d t o volume w i t h e t h y l a c e t a t e . a

R

a n c


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The p e s t i c i d e c o n c e n t r a t i o n s were determined by g a s - l i q u i d chromatography (GLC) u s i n g a T r a c o r Model 222 chromatograph equipped w i t h a 6^Ni e l e c t r o n c a p t u r e d e t e c t o r . The column was U-shaped g l a s s (183 by 0.2 cm i d ) packed w i t h a 1:1 m i x t u r e of 1.5% 0V-17 + 3% Q F l and 3% 0F-1 on Supe.lcoport (80/100). The c a r r i e r gas was N2 at a flow r a t e of 70 mL/min through the column and 20 mL/min t o the d e t e c t o r . Temperatures were as f o l l o w s : oven, 190 C; d e t e c t o r , 285 C; i n l e t , 225 C. Data were q u a n t i t a t e d by the p e a k - h e i g h t method u s i n g the peaks o f compound 0 (RT 7.4 min) compound Ε (RT 10.8 min) t r a n s c n l o r d a n e (RT 16.2 min); c i s - c h l o r d a n e (RT 18.4 min), and t r a n s n o n a c h l o r (RT 19.2 m i n ) . The peaks were added t o g e t h e r and d i v i d e d by the i n j e c t i o n volume. H e p t a c h l o r was not measured i n c h l o r d a n e samples but was i n the Termide samples. The normal c o n c e n t r a t i o n o f h e p t a c h l o r i n t e c h n i c a l c h l o r d a n e averaged 10% and t h i s amount was s u b s t r a c t e d from the h e p t a c h l o r peak i n samples c o n t a i n i n g Termide. The low d e t e c t a b l e l i m i t s were: c h l o r d a n e , 0.01 \ig; h e p t a c h l o r , 0.005 pg. Samples were i n j e c t e d by a Dynatech Model GC 211V P r e c i s i o n Sampler (Dynatech P r e c i s i o n Sampling Corp; P. 0. Box 15119; Baton Rouge, LA 70895) c o n t r o l l e d by a L i n d b e r g E n t e r p r i s e s C o n t r o l Model "CD" Timer. ( L i n d b e r g E n t e r p r i s e s , I n c . ; 9707 Candida S t . , San Diego, CA 92126). I n j e c t i o n volumes were 3 pL and time between i n j e c t i o n s was 35 min. Two a n a l y t i c a l s t a n d a r d s , one c o n t a i n i n g c h l o r d a n e and the o t h e r h e p t a c h l o r , were p l a c e d a f t e r e v e r y 5 samples f o r q u a n t i t a t i o n purposes. E f f i c i e n c y o f the e x t r a c t i o n p r o c e s s e s was m o n i t o r e d by f o r t i f y i n g u n t r e a t e d s o i l s and foam p l u g s w i t h known amounts of c h l o r d a n e o r h e p t a c h l o r and c a r r y i n g t h e s e t h r o u g h the a n a l y t i c a l p r o c e s s . Two f o r t i f i e d samples were e x t r a c t e d w i t h each set o f s o i l or foam-plug samples. A l l data were s u b j e c t e d t o an a n a l y s i s of v a r i a n c e , and the r e s u l t i n g s t a t i s t i c a l parameters were used i n p o i n t i n g out d i f f e r ences between means. R e s u l t s and

Discussion

Houses were numbered c o n s e c u t i v e l y from 1 t o 60, and a l l sample numbers i n a l l T a b l e s r e f e r t o the same house. Samples were c o l l e c t e d over a 3-month p e r i o d between June and September, 1983. Average temperatures i n c l a y s o i l s and the s u r r o u n d i n g c r a w l space were 20.6 and 22.9 C, r e s p e c t i v e l y ; f o r sandy s o i l s and the a s s o c i a t e d c r a w l space temperatures averaged 19.8 and 23.6 C, r e s p e c tively. House temperatures v a r i e d w i d e l y between 21 and 31 C, because of the use o f a i r c o n d i t i o n i n g i n a number o f d w e l l i n g s and the 3-month sampling i n t e r v a l . For t h e s e same r e a s o n s the r e l a t i v e h u m i d i t i e s i n homes ranged from 49 to 79%, w h i l e i n the c r a w l spaces, the range was from 52 t o 967

Subterranean Termite Control: Chlordane Residues in Soil

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