En vironmental Pollution 85 (1994) 147-151 ORGANOCHLORINE PESTICIDE RESIDUES IN HUMAN MILK IN PUNJAB, INDIA R. L. Kalra, Balwinder Singh & R. S. Battu Department of Entomology, Punjab Agricultural University, Ludhiana, Punjab, India Abstract Human milk samples collected from areas having inten- sive cotton cultivation and sparce cotton cultivation in Punjab (India) were analysed for organochlorine insecti- cides. Both DDT and HCH were detected in almost all the samples analysed. The average levels of ]~-DDT and ~-HCH residues in samples from cotton-growing areas were significantly higher than in those from areas where cotton is sparsely grown. Residues of Y-DDT mainly comprised p, p'-DDT and p, p'-DDE, while those of Y- HCH residues were mainly in the form of its ~-isomer. Median values of 0.52 Ixg g l of ]~-DDT and 0.19 Ixg g l of Y~-HCH in samples of human milk from cotton- growing areas of Punjab (India) were higher than those reportedJrom most other countries in the World. INTRODUCTION The presence of xenobiotics in mother's milk is viewed with serious concern all over the world. Amongst the environmental toxic compounds, organo- chlorine pesticides have been reported to be the main contaminants of human milk (Wasserman et al., 1975; Farver, 1979; Jensen, 1983). In cotton-growing areas of Guatemala, residues of total (Y~-) DDT as high as 4.07 /zg g~ were observed, as compared to 1.83 and 2.15 p~g g~ outside the cotton-growing areas (Olszyna- Marzys et al., 1973). A few surveys carried out in India have revealed the presence of DDT and HCH residues at high levels in human milk (Kalra & Chawla, 1981; Saxena & Siddiqui, 1982). The present paper reports the comparative levels of residues of these insecticides in the cotton-growing and other areas of the Punjab, India. MATERIAL AND METHODS Sampling Human milk samples were collected from 82 lactating women living in cotton-growing areas of Faridkot dis- trict and from 47 women living in Ludhiana district where cotton is sparsely grown. Each woman expressed approximately 20 ml of milk either by hand or with a clean breast pump. The breast pump was washed Environ. Pollut. 0269-7491/94/$07.00 © 1994 Elsevier Science Limited, England. Printed in Great Britain 147 thoroughly with soap and water and rinsed with n- hexane before use. Solvent washes were examined by gas-liquid chromatography for contaminants; none were found. Information on age, weight, number of births, interval between delivery and sampling, and feeding habits was obtained. Chemicals Solvents were distilled in all-glass apparatus before use. All other chemicals were analytical grade and were used as such. The suitability of the reagents/solvents was checked by running reagent blanks. Pesticide standards HCH (a-, /3-, y- and &isomers), p,p'-DDE, p,p'-TDE, p,p'-DDT, o,p'-DDE, o,p'-TDE, o,p'-DDT and DDMU (all > 95% purity) were obtained from the US Environ- mental Protection Agency, North Carolina and were used as reference standards. Extraction and clean-up The extraction and clean-up of the human milk samples were done according to the method of Kalra and Chawla (1981). A 5-g sub-sample of human milk was homogenized with 20 ml of acetone : n-hexane (1 : 1, v/v) mixture. The homogenate was allowed to stand until a clear separation into two layers had occurred. After the removal of the upper organic phase, the lower phase was re-extracted twice with 10 ml n- hexane. The combined organic phase was evaporated until almost free of the solvent. The residue was dis- solved in about 25 ml n-hexane and was cleaned up by dropwise addition of concentrated sulphuric acid (specific gravity 1.84) in a stoppered glass column. The lower phase containing H2SO 4 and digested lipids was continuously discarded from the stoppered glass column. The upper n-hexane phase was washed with distilled water until neutral to litmus and was then concentrated to a suitable volume and analysed on a gas chromatograph. Gas chromatographic analysis The residues of pesticides in the cleaned-up extract were quantified on a Packard Gas-Chromatograph (Model 417) equipped with a tritium foil electron- capture detector. Two different columns were used to