Residues of hexachlorocyclohexane isomers in soil and water samples from Delhi and adjoining areas

Forty-five soil samples of surface (0–15 cm) and subsurface (15–30 cm) soils from agricultural sites of Delhi, Haryana, Haridwar, Uttar Pradesh (UP) and around the hexachlorocyclohexane (HCH) manufacturing plant of IPL (Indian Pesticide Limited) and nine samples of different commercial brands of drinking water from markets in Delhi were analysed for the presence of residues of HCH isomers. Thirty-nine of the 45 soil samples contained residues of β-HCH (2.5 μg/kg to 463 mg/kg of soil) and the remaining showed the presence of γ-HCH (0.08 μg/kg to 43.00 mg/kg). Residues of α-HCH (0.04 μg/kg to 98.00 mg/kg of soil) and δHCH (0.07 μg/kg to 458.00 mg/kg of soil) were detected less frequently. All the nine samples of drinking water were found to contain residues of γ-HCH and βHCH, whereas only 5 and 4 samples contained αand δ-HCH respectively. Bisleri, Paras and VIP brands showed 99, 240 and 141 fold higher levels of HCH respectively when compared the EEC norms. The contamination of mineral water could be due to heavy contamination of groundwater, which is used for making mineral water.