Standardization of Multiresidue Methodology for Pesticides and Their Distribution in Yamuna River Water, Delhi and Aakulam Lake Water, Kerala

A simple and reliable multiresidue methodology for the analysis of pesticides (atrazine, lindane, metribuzin, aldrin, chlorpyriphos, pendimethalin, α- endosulfan, β- endosulfan, p,p′-DDT, cypermethrin) and two metabolites (endosulfan sulfate and p,p′-DDE) has been standardised and distribution of these pesticides in water of Yamuna river (Wazirabad 1&2 and Okhla region) and Aakulam lake, Kerala were studied. Instrumental parameters were standardized for proper resolution and sensitivity. For extraction of pesticides from the water, liquid-liquid partitioning with dichloromethane was found to be most effective with an extraction efficiency of 80.6–92.3%. For the cleanup of the water extract, a florisil column using 20:80 acetone:hexane as the eluting solvent gave recovery of 85.9–97.4%. The method (extraction+cleanup) recovery varied from 80.4–90.0%. The residues of pesticides detected in water samples varied from trace to 0.481 μg/L and the concentration of lindane, p,p′-DDE, endosulfan sulfate and p,p′-DDT was below the safe limit for drinking water. No residue of atrazine, metribuzin, aldrin, chlorpyriphos, pendimethalin and cypemethrin were detected in any of the water samples. In Aakulam lake water only residues of endosulfan were detected at concentration of 0.224, 0.234 and 0.131 μg/L of α-, β-endosulfan and endosulfan sulfate, respectively.