Pesticide Disposal Sites: Sampling and Analyses - American

5 Pesticide Disposal Sites: Sampling and Analyses G.A.JUNK and J. J. RICHARD

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on March 17, 2017 | http://pubs.acs.org Publication Date: August 15, 1984 | doi: 10.1021/bk-1984-0259.ch005

Ames Laboratory, Iowa State University, Ames,IA50011

Pesticides and their degradation products were analyzed in samples taken from two disposal pits located at Iowa State University, Ames, IA. The first was an eight-year-old 30,000 L concrete-lined pit where over 50 kg of more than 40 different pesticides had been deposited. The second was a two-year-old 90,000 L polyethylene-lined pit where 150 kg of 24 different pesticides had been deposited. The pesticide concentrations i n the s o i l and l i q u i d samples taken from these pits showed extreme variations which necessitated c o l l e c t i n g and compositing samples from many different points to estimate the average pesticide concentrations and their change with time. Water, s o i l and a i r samples were also collected and analyzed to evaluate the possible contamination of the surrounding environment. Summarized conclusions from these investigations are: 1) pit disposal systems are effective i n containing many pesticides to the extent that release to surrounding air and water i s i n s i g n i f i c a n t ; 2) possible environmental effects can be established by avoiding the extreme d i f f i c u l t i e s associated with solid samples and taking only l i q u i d samples for analyses; 3) p i t disposal systems are effective for pesticides as well as other organic chemicals.

0097-6156/84/0259-0069$07.75/0 © 1984 American Chemical Society

Krueger and Seiber; Treatment and Disposal of Pesticide Wastes ACS Symposium Series; American Chemical Society: Washington, DC, 1984.

T R E A T M E N T A N D DISPOSAL OF PESTICIDE WASTES

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The three main goals of the d i s p o s a l of d i l u t e s o l u t i o n s of waste p e s t i c i d e s are containment, d e t o x i f i c a t i o n and volume r e d u c t i o n . To meet these goals two p i t s have been constructed for the d i s p o s a l of p e s t i c i d e waste connected with h o r t i c u l t u r e and agronomy operations at Iowa State U n i v e r s i t y . This paper deals with the sampling and chemical analyses of the s o i l and l i q u i d contents from these p i t s plus water, s o i l and a i r samples from the sur rounding area to help answer questions concerning containment and degradation of the deposited p e s t i c i d e s . EXPERIMENTAL D e s c r i p t i o n of D i s p o s a l P i t s D e t a i l e d d e s c r i p t i o n s of the two d i s p o s a l p i t s located at the H o r t i c u l t u r e and Agronomy farms at Iowa State U n i v e r s i t y , Ames, IA, have already been published ( 1 ) . B r i e f summaries of the con s t r u c t i o n s and operations are presented below for those who do not have easy access to that report (_1). H o r t i c u l t u r e P i t . The h o r t i c u l t u r e p i t was constructed i n 1969-70 and has been i n continuous use since that time. The 8.8 χ 3.4 m concrete p i t has an average depth of 1 m and has been f i l l e d with a l t e r n a t e 30 cm l a y e r s of gravel and s o i l as shown i n Figure 1. The s o i l i s a s i l t loam ( C l a r i o n - N i c o l e t t - W e b s t e r ) c h a r a c t e r i s t i c of C e n t r a l Iowa. A cover closes a u t o m a t i c a l l y to prevent p r e c i p i t a t i o n from e n t e r i n g . A t i l e system constructed below the con c r e t e f l o o r of the p i t connects to a sump for sampling of the ground water. The 30,000 L p i t has had over 50 kg of more than 40 d i f f e r e n t p e s t i c i d e s deposited since beginning o p e r a t i o n . Agronomy P i t . The p i t at the Agronomy-Agricultural Engineering Research Center was constructed i n 1977 and used for the 1978 and 1979 growing seasons. As shown i n Figure 2, the p i t i s 1.7 m deep with surface dimensions of 13.7 χ 7.3 m. The t o t a l volume of the p i t i s ~90,000 L. Five v e r t i c a l t i l e , 15 cm i n diameter, are used for l i q u i d sampling. A galvanized metal pipe i n an H shape i s buried w i t h i n the rock and used as a d i s t r i b u t i o n system. A n i p ple extends above the rock surface for coupling to o u t l e t s of sprayer r i g s . The waste p e s t i c i d e mixtures are thus d i s t r i b u t e d over the p i t area by g r a v i t y flow and drainage from the holes



5. J U N K A N D R I C H A R D

Disposal Sites: Sampling and Analyses

71

Figure 1. C r o s s - s e c t i o n of covered 8.8 χ 3.4 m c o n c r e t e l i n e d H o r t i c u l t u r e p i t with a l t e r n a t e l a y e r s of rock (cross hatched) and s o i l (slanted l i n e s ) .

Figure 2. C r o s s - s e c t i o n o f canopied 13.7 χ 7.3 m p l a s t i c - l i n e d Agronomy p i t with a d i s t r i b u t i o n system ( s o l i d bar) embedded in rock (cross-hatched) and f i v e sampling t i l e s extending through the rock and s o i l (slanted l i n e s ) .


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T R E A T M E N T A N D DISPOSAL O F PESTICIDE WASTES


d r i l l e d i n the pipe. The wooden canopy prevents p r e c i p i t a t i o n from entering the p i t . The p i t was l i n e d with two sheets of continuous black polyethylene encompassed on both sides by layers of sand. M e t a l l i c hardware c l o t h was also l a i d on the outside s o i l sand i n t e r f a c e to stop burrowing rodents. The p i t was b a c k f i l l e d to a depth of 1.22 m with the o r i g i n a l s i l t loam s o i l , and then a 0.46 m layer of crushed rock was added to the s u r f a c e . Since beginning operation i n 1978, ~150 kg of 24 d i f f e r e n t p e s t i c i d e s have been deposited. Sampling H o r t i c u l t u r e P i t . Core samples of s o i l of about 100 g s i z e to a depth of 10 cm and l i q u i d samples of 500 mL were taken from eight sampling points spaced uniformly across the p i t s u r f a c e . Each sample was then solvent extracted i n d i v i d u a l l y and the p e s t i c i d e s and degradation products were separated and q u a n t i t a t e d . To e s t a b l i s h whether a composited sample would give r e s u l t s equivalent to the average of the i n d i v i d u a l analyses, eight samples were taken i n October 1977. A p o r t i o n of each sample was formed into a s i n g l e composite and a l l samples were then analyzed. Results for the average of eight i n d i v i d u a l samples and the comp o s i t e agreed w i t h i n 2%. Therefore a l l samples a f t e r October 1977 were composited. Water samples were also c o l l e c t e d from the drainage t i l e surrounding t h i s c o n c r e t e - l i n e d p i t . Other water samples were taken from s i t e s remote from the p i t l o c a t i o n . A i r samples for p e s t i c i d e vapor analyses were c o l l e c t e d i n the v i c i n i t y of the pit. Agronomy P i t . L i q u i d samples only were c o l l e c t e d from f i v e access t i l e s at the Agronomy p i t . These were analyzed i n d i v i d u a l l y and as a composite, with r e s u l t s agreeing w i t h i n 2%. No s o i l samples were taken from w i t h i n the Agronomy p i t . One set of s o i l samples to a depth of 3 m was taken from 10 cm diameter holes augered at each outside corner of the p i t . Water samples from outside the p i t were also c o l l e c t e d from the seepage of ground water i n t o the augered holes and from other s i t e s remote from the p i t l o c a t i o n . A i r samples f o r p e s t i c i d e vapor analyses were c o l l e c t e d i n the v i c i n i t y of the p i t . E x t r a c t i o n Procedures The procedures employed for the l i q u i d , s o i l , water and a i r samples are described and discussed below. L i q u i d Samples. Three procedures were evaluated for e x t r a c t i n g p e s t i c i d e s from l i q u i d samples c o l l e c t e d at the H o r t i c u l t u r e and Agronomy p i t s . They were the r e s i n s o r p t i o n method of Junk et a l . (2), solvent e x t r a c t i o n with hexane-diethylether, and solvent



5. J U N K A N D R I C H A R D


73

e x t r a c t i o n with methylene c h l o r i d e . Comparable recoveries were achieved for a l l three procedures. The methylene c h l o r i d e procedure was chosen because of the ready a v a i l a b i l i t y of pure solvent and the s i m p l i c i t y of the method. L i q u i d samples c o l l e c t e d at the Agronomy p i t were p a r t i a l l y s t a b i l i z e d suspensions which required pretreatment p r i o r to the extraction. The pretreatments which were i n v e s t i g a t e d were 24 hour s e t t l e , 24 hour s e t t l e plus one hour c e n t r i f u g i n g at 2500 rpm, and 24 hour s e t t l e plus one hour c e n t r i f u g i n g plus f i l t e r i n g through a 1 to 2 micron f i l t e r . These three methods were used f o r the l i q u i d samples c o l l e c t e d i n August of 1978. The r e s u l t s are tabulated i n Table I. For most of the p e s t i c i d e s comparable r e s u l t s were obtained with the amounts a f t e r c e n t r i f u g i n g and f i l t e r i n g g e n e r a l l y being lower. These samples also had the lowest t u r b i d i t y and thus were more representative of true d i s s o l v e d constituents. A l l samples c o l l e c t e d a f t e r August 1978 were s e t t l e d f o r 24 hours and then c e n t r i f u g e d and f i l t e r e d before extraction.

Table I. Concentration D i f f e r e n c e i n L i q u i d Samples from Agronomy P i t when S e t t l i n g , C e n t r i f u g i n g and F i l t r a t i o n are Employed PPM Herbicide 24 hour Settle EPTC Butylate Chlorpropham Propachlor Atrazine Trifluralin Alachlor Cyanazine Metribuzin

7 13 15 132 279 189 318 97 111

Centrifuge 4 7 8 110 193 108 223 119 100

Centrifuge + Filter 2 3 6 32 174 51 171 109 138

S o i l Samples. Five methods of e x t r a c t i o n were evaluated f o r s o i l samples c o l l e c t e d at the H o r t i c u l t u r e p i t . The r e s u l t s for t h i s e v a l u a t i o n are tabulated i n Table I I . The Woolson procedure (3) was selected f o r use throughout the course of our i n v e s t i g a t i o n s of a l l s o i l and sediment samples. Water Samples. The p e s t i c i d e residues i n ground water samples from s i t e s adjacent to and remote from the d i s p o s a l p i t l o c a t i o n s and the well water samples were analyzed by the r e s i n s o r p t i o n method using XAD-2 as described by Richard et a l . (4) and Junk et a l . (5) for measuring very low amounts of selected p e s t i c i d e s .


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T R E A T M E N T A N D D I S P O S A L OF PESTICIDE WASTES

Table I I . Comparison of Various Solvents and E x t r a c t i o n Procedures for Recovery of P e s t i c i d e s from a H o r t i c u l t u r e P i t Sample PPM


Pesticide Bensulide Chlorothalonil DCPA Dichlobenil Endosulfan I Endosulfan I I Hexachlorobenzene Methoxychlor Phosmet Trifluralin T

l 2 3 4 5

1 26 162 1116 4 38 23 89 93 4 36

by Method Number^

2

3

4

5

16 184 1141 2 37 23 91 95 2 30

22 193 1129 3 36 22 89 93 3 22

24 196 1054 5 36 22 82 93 3 20

24 146 1017 4 35 21 79 91 2 22

= batch e x t r a c t i o n using hexane-acetone according to procedure by Woolson (1974) = u l t r a s o n i c e x t r a c t i o n using i s o p r o p y l a l c o h o l = u l t r a s o n i c using hexane-acetone = u l t r a s o n i c using benzene-isopropyl a l c o h o l = soxhlet e x t r a c t i o n using hexane-acetone

A i r Samples. The atmospheres i n the v i c i n i t y of the p i t s were sampled for p e s t i c i d e vapors using XAD-2 r e s i n and a vacuum pump (6). C o l l e c t i o n e f f i c i e n c i e s for t h i s method were measured i n the l a b o r a t o r y using simulated atmospheres and found to be 99.5% average f o r 10 p e s t i c i d e s spiked at 10 ng/L of a i r . Separation and D e t e c t i o n Procedures The m a j o r i t y of the p e s t i c i d e s were separated by gas chromatography and detected by a v a r i e t y of general and s p e c i f i c detectors such as flame i o n i z a t i o n , e l e c t r o n capture, flame photometric, e l e c t r o n impact and chemical i o n i z a t i o n mass spectrometric and nitrogen-phosphorus. Two columns were most u s e f u l for s e p a r a t i n g the p e s t i c i d e s i n the e x t r a c t s of the samples c o l l e c t e d from the H o r t i c u l t u r e and Agronomy d i s p o s a l p i t s . These two columns were a 4% SE-30/6% OV210 and a 10% DC-200. A 30 m SE-54 glass c a p i l l a r y column was employed for more complete separations when necessary to a i d i n i d e n t i f i c a t i o n and analyses procedures. R e l a t i v e retent i o n times of s e v e r a l p e s t i c i d e s and methyl esters are given i n Table I I I for the SE-54 glass c a p i l l a r y column.



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JUNK A N DRICHARD


75

Some of the p e s t i c i d e s deposited i n the d i s p o s a l p i t s were not gas chromatographable d i r e c t l y . These required s p e c i a l t r e a t ment to give products that could be determined by gas chromatography or by other procedures. These p e s t i c i d e s and the procedures employed for t h e i r analyses are discussed below. Benomyl was extracted and i s o l a t e d by the procedure of A u s t i n and Briggs (_7). A f t e r i s o l a t i o n and c o n c e n t r a t i o n , benomyl and i t s metabolites were determined c o l o r i m e t r i c a l l y . Mancozeb, Maneb, Polyram and Dithane i n s o i l and water samples were analyzed using the head space procedure for screening food samples for dithiocarbamate p e s t i c i d e residues as described by McLeod and McCully ( 8 ) . Paraquat was determined i n s o i l and water samples by the e x t r a c t i o n and gas chromatographic procedure of King (9). A c i d i c p e s t i c i d e s and metabolites were concentrated from aqueous s o l u t i o n by the anion procedure of Richard and F r i t z (10) . The anionic m a t e r i a l s i n these concentrates were methylated using diazomethane and the dérivâtized products were separated and detected by gas chromatography. Test r e s u l t s of the recovery e f f i c i e n c i e s by t h i s method for s e v e r a l p e s t i c i d e s and suspected met a b o l i t e s have been reported elsewhere (11). An o v e r a l l recovery of 93% was achieved for s i x t e e n a c i d i c p e s t i c i d e s and metabolites spiked into water at 200 ppb. RESULTS AND

DISCUSSION

Segregation I n d i v i d u a l analyses of both s o i l and l i q u i d samples taken from the H o r t i c u l t u r e p i t e s t a b l i s h e d unequivocally the extreme segregation of the p e s t i c i d e s . V a r i a t i o n s i n concentrations for samples c o l l e c t e d at eight sampling points i n October .1977 were extreme as shown i n Table IV, being ~1100 for DCPA i n s o i l samples and ~50 for phosmet i n water samples. S i m i l a r evidences of segregation were also found for s o i l and water samples c o l l e c t e d e a r l i e r i n March, June and August of 1977. The greatest d i f f e r e n c e i n conc e n t r a t i o n for s o i l samples was observed i n June where DCPA v a r i e d from 4 to 13400 ppm. For water samples, the maximum segregation was for hexachlorobenzene, also i n June, which v a r i e d from 0.1 to 50 ppm. These wide ranges i n concentrations are probably due to uneven d e p o s i t i o n s of the waste p e s t i c i d e s and t h e i r very slow m o b i l i t y i n systems containing rock, s o i l and a l i q u i d phase. S i m i l a r segregation was observed i n l i q u i d samples c o l l e c t e d from the Agronomy p i t where a system was i n s t a l l e d to uniformly d i s t r i b u t e the p e s t i c i d e s . Concentrations of p e s t i c i d e s v a r i e d by a f a c t o r as high as 10 i n the June 1978 l i q u i d samples as shown i n Table V. The extreme v a r i a t i o n i n the chemical composition of samples taken from d i f f e r e n t l o c a t i o n s w i t h i n the H o r t i c u l t u r e and Agron-


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Table I I I . R e l a t i v e Retention Times of Various P e s t i c i d e s or Their Methyl E s t e r s (M.E.) on a SE-54 C a p i l l a r y Column Pesticide

Pesticide

Trimethylphosphate 0.09 Dimethylthiophosphate 0.18 Dimethyldithiophosphate 0.22 2,4-Dichlorophenol-M.E.* 0.33 Linuron 0.34 Dichlobenil 0.42 Eptam 0.43 2,6-Dichlorobenzoic Acid-M.E. 0.45 Tetrahydrophthalimide-M.E. 0.49 Butylate 0.50 2,4,5-Trichlorophenol-M.E. 0.51 Tetrahydrophthalimide 0.59 Dicamba-M.E. 0.63 MCPA-M.E. 0.63 MCPP-M.E. 0.64 Propachlor 0.71 Chlorpropham 0.74 2,4-D-M.E. 0.74 BHC 0. 74, 0.80 Trifluralin 0.78 Pentachlorophenol-M.Ε. 0.79 Hexachlorobenzene 0.79 Lindane (γ) 0.81 Dealkylalachlor 0.81 Chloramben-M.E. 0.82 Benzimidazole 0.83 Atrazine 0.84 Diamino t r e f l a n 0.85 Simazine 0.85 Profluralin 0.85

Dimethoate 0.85 Nitroamino t r e f l a n 0.87 0.88 Dinitramine 0.88 Fluchloralin 2,4,5-T-M.E. 0.89 0.92 Chlorothalonil 0.93 Bentazon-M.E. 0.95 Metribuzin 0.96 Endosulfan I 0.97 Alachlor 0.98 Chloroxuron 1.00 Aldrin 1.02 Metolachlor 1.03 Malathion 1.04 DCPA E t h y l Parathion 1.05 Heptachlor Epoxide 1.07 1.08 Cyanazine 1.09 Butralin 1.09 Penoxalin 1.11 Captan 1.11 Folpet Kelthane 1. 15, 1.21 1.20 ρ,ρ'-DDE 1.22 Dieldrin 1.22 Endosulfan I I 1.27 ρ,ρ'-DDD 1.33 ρ,ρ'-DDT 1.42 Methoxychlor 1.47 Naptalam-M.E.

Temperature programmed at 5°/min from 80-270° M.E. = methyl ester


fc

R


2

2

2

2

2

Dichlobenil

Endosulfan I

Endosulfan I I

EPTC

2

2

Propachlor

2

Hexachlorobenzene Phosmet

2

2

H0 Soil H0 Soil H0 Soil H0 Soil H0 Soil H 0 Soil H0 Soil H0 Soil H0 Soil H0 Soil

Sample Type

Azinphos-Methyl Chlorothalonil DCPA

Pesticide

0.3 384 0.2 108 0.9 492

Pesticide Disposal Sites: Sampling and Analyses - American

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