The Science of the Total Environment, 108 (I 991 ) 255-259 Elsevier Science Publishers B.V., Amsterdam

255

Levels of aldrin and dieldrin in environmental samples from Delhi, India A. Nair ~, P. Dureja b and M.K.K. Pillai ~ "'Department of Zoology, University of Delhi. New Delhi ! 10002, India "Division of Agricultural Chemicals, Indian Agricultural Research Institute. New Delhi 110012, India

(Received May 20th, 1990; accepted August 20th, 1990)

ABSTRACT Aldrin and dieldrin residues in soil, earthworms, water, fish and clams from different sites in Delhi were monitored. Concentrations of aidrin and dieldrin were found to be higher in earthworms than in soil. Concentrations of dieldrin were higher in fish than the ambient water, but the concentration of aldrin in the ambient water was the same as that in fish and clams.

INTRODUCTION D D T has been detected in soil and earthworm samples collected from dif.ferent sites in Delhi (Yadav et al., 1981), but there are no i)ublished data on the presence of aldrin and dieldrin in soil, earthworms, fish, water and clam samples from this area. This study was undertaken to assess the extent of aldrin and dieldrin pollution at different sites in Delhi. MATERIALS AND METHODS Samples analysed for aldrin and dieldrin residues were collected in 1988 and 1989. Samples of sandy loam soil were taken from the upper l 0 cm at different sites in Delhi, using a soil auger, and earthworms were collected from the same sites. Water samples, fresh water clams and fish were collected from the upstream and downstream sections of the River Jamuna in Delhi. Analysis was carried out following the procedures of the EPA (1980), with certain modifications. Soil samples (50g) were extracted with 150ml acetone/hexane ( ! : 1 ) Ja a Soxhlet apparatus for 8 h. Samples of animal tissue ( ~< l 0 g) were ground with four times their weight 0048-9697/91/$03.50 © 1991 -- Elsevier Science Publishers B.V. All rights reserved

256

A, NAIR ET AL.

TABLE I

Mean and range of aldrin in different environmental samples (/ag/g) Sample

n

Mean

SD

SE

Range

Soil Earthworms Water ~ Fish Clams

27 !4 20 20 12

0.0 i 3 0.017 0.0 ! 4 0.014 0.017

0.064 0.024 0.0234 0.019 0.022

0.001 0.0067 0.005 0.004 0.006

0.0003-0.12 0.0004-0. ! 5 0.0005-0.05 0.0001-0.03 0.0002-0.01

;' ligiml.

of anhydrous sodium sulphate using a mortar and pestle prior to Soxhlet extraction. Water samples Ci0 ml) were extracted with 75 ml of dichloromethan¢ followed by two 35 ml portions of dichloromethane (Holden and Marsden, 1969). The extracted soil and animal tissue samples were partitioned in n-hexane (Chau, 1972), concentrated and then cleaned on an alumina column with 60 ml n-hexane. The water extracts were concentrated to 0.5 ml and eluted on a silica gel column with 10ml n-hexane (EPA, 1980). These cleaned samples were analysed by gas-liquid chromatography.

Analytical procedures A Hewlett-Packard Model 5890A gas-liquid chromatogram equipped with an electron capture detector and coupled to an integrator was used for analysis of the environmental samples. A capillary column (0.53 mm i.d., 10 m long) packed with 3% OV-17 was used. The operating conditions were: column temperature, initial temperature 200°C for 3 min, then a programmed TABLE 2 Mean and range of dieldrin in different environmental samples (lig/g) Sample

n

Mean

SD

SE

Range

Soil Earthworms Water ~ Fish Clams

27 14 20 20 12

0.004 0.005 0.02 0.03 0.01

0.006 0.004 0.0 ! 3 0.02 0.01

0.00 i 0.001 0.0028 0.005 0.0039

0.0002-0.03 0.0005-0.03 0.000 I-0.1 0.0001-0.2 0.0001-0.05

"~lg/ml.

LEVELS OF ALDRIN AND DIELDRIN IN ENVIRONMENTAL SAMPLES

257

,o r 0

.0!

iloo .0001

I

.001

.0|

0.1

1.0

RESIDUE IN SOIL

Fig. I. Relationship between level of aldrin in soil and that in earthworms.

increase of 10°C/min to 250°C final temperature; detector and injector temperature, 300°C. Nitrogen was used as the carrier gas with a flow rate of 53 m]/min. Samples of aldrin and dieldrin were obtained from EPA. Average recovery was > 90%. The presence of aldrin and dieldrin in the samples was confirmed by G C-MS (Model JEOL JMS D300). RESULTS A N D DISCUSSION

The concentrations of aldrin and dieldrin residues in the samples, collected from different sites in Delhi, are shown in Tables l and 2. Aldrin and dieldrin residues in soils ranged from 0.0003 to 0.12 and from 0.0002 to 0.03 #g/g, respectively. A linear relationship was observed (Figs l and 2) between the amount of aldrin and dieldrin taken up by earthworms and the level in the soil. Hence earthworms are good indicator organisms for soil aldrin and

i.Oi

Z

o

7,_ooo,

,~o-

,

oo,

,

.o,

,

o.,

,

,o

RESIDUE IN SOIL

Fig. 2. Relationship between level of dieldrin in soil and that in earthworms.

258

A. NAIR ET AL.

1.0 F I SH ol

zl

.o~

1,oo, 1oo,

, 001

.01

I O.I

I I.O

RESIDUE IN WATER

Fig. 3, Relationship between level of aldrin in water and fish and clams.

dieldrin residues content since they ingest a large quantity of soil. A similar observation was made by Wheatley and Hardman (1968) for the amount of pesticides taken up by earthworms and the level in the soil; a general proportionality was found between the levels of pesticides in the soil and that in the earthworms. The presence of dieldrin in earthworms is due to either its direct uptake from soil or by conversion of aldrin to dieldrin by oxidising enzymes during digestion. The levels of dieldrin in soil and earthworms were found to be lower than those of aldrin. This could be due to the ban on the use of dieldrin in agriculture. The aidrin and dieldrin residues in water samples collected from different sites upstream and downstream of Delhi ranged from 0.0005 to 0.05 and from 0.0001 to 0.1 Fg/ml. Dieldrin concentrations in water samples were higher

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