Distribution and Risk Assessment of Aldrin, Endrin, Heptachlor, and Heptachlor Epoxide in Some Villages in Hawul River Basin

Aldrin, endrin, heptachlor, and heptachlor epoxide were investigated to assess their distribution in the environmental compartments of the Hawul River basin with emphasis on surface water, sediment, and fish (clarias gariepinus). GC-MS was used for the identification and quantification of the pesticide residues after extraction and clean-up of the residues using the QuEChERS method. The results indicated a high concentration of the OCPs analyzed with some locations having concentrations above the recommended MRLs values. Aldrin and endrin are the most abundant of the OCPs analyzed with 0.3mg/L and 0.04mg/L as their lowest concentration in water samples, which is above the 0.01 μg/L MRL recommended by WHO. The total OCPs burden is in the order of Garkida > Kopre > Garkida WB > Daba > Kiri > Dabna. The health risk which was computed using the Hazard Quotient and Hazard Index shows Aldrin and Endrin have HQ greater than 1 in all sampling locations in a range of 1.39 – 9.85, 1.85 – 6.44 while heptachlor and heptachlor epoxide were less than 1 in the range of 0.03 – 0.56 and 0.006 – 0.07 due to fish consumption. The HI which is the cumulative effect of the individual OCPs in fish was in the sequence Garkida (WB) > Kiri > Kopre > Garkida > Dabna > Daba. Keywords: Physicochemical parameters, Groundwater quality, Water quality index, Karachi.