Residual analysis of menacing toxicants: pesticides and heavy metals in fish (Oreochromis niloticus and Tor putitora) and fresh water reservoirs

Current research was done to evaluate the level of pesticide residues and heavy metals in fish and water bodies. Surface water samples and samples of Oreochromis niloticus and Tor putitora were collected from different sites from Rawal and Simly Dams. Following the physicochemical analysis of water samples, heavy metals were analyzed by Atomic Absorption Spectrophotometer (AAS) while pesticide residues were detected by GC–MS. Acid digestion of fish muscles was done for heavy metal analysis. Soxhlet extraction was used to extract pesticide residues from fish samples, which were concentrated in a rotary evaporator followed by GC–MS analysis. The physicochemical analysis of water samples revealed pH within the WHO guidelines. Pb, Cr, Cd, and Ni found in Rawal and Simly Dam water were higher than the prescribed WHO guidelines. The average heavy metal concentration in all fish samples was also high. Toxic pesticides detected in Rawal Dam water and fish samples included HCB, Heptachlor, 2, 4′-DDT, 4, 4′-DDT, and 4, 4′-DDE, whereas HCB, PP-DDT, OP-DDE, and Chlordane were detected in Simly Dam water and fish samples. The study emanates the menace of possible bioaccumulation of heavy metals and toxic pesticides in food chain.