Study of seasonal variations and health risk assessment of heavy metals in Cyprinus carpio from Rawal Lake, Pakistan.

This study was carried out to find out the comparative distribution of heavy metals (Fe, Cu, Mn, Zn, Co, Cr, Cd and Pb) in various tissues (muscles, gills, liver, stomach and intestine) of Cyprinus carpio from Rawal Lake, Pakistan, during summer and winter. Relatively higher concentrations of Cd, Co, Cr, Cu, Fe and Zn were found in the stomach samples, while the highest Pb and Zn levels were noted in muscle and intestine samples, respectively. Correlation study exhibited diverse relationships among the metals in various tissues. Generally, the metal concentrations found during the summer were comparatively higher than the winter. Potential non-carcinogenic and carcinogenic health risks related to the metals in C. carpio were evaluated using the US Environmental Protection Agency approved cancer risk assessment guidelines. The calculated daily and weekly intakes of Pb, Cd, Cr and Co through the fish consumption were significantly higher than the permissible limits. In relation to the non-carcinogenic risks to human, Pb, Cd, Cr, Co and Zn levels were higher than the safe limits; however, carcinogenic risks related to Cr (3.9 × 10(-3) during summer and 1.1 × 10(-3) during winter) and Pb (2.6 × 10(-4) during summer and 1.5 × 10(-4) during winter) clearly exceeded the safe limit (1 × 10(-6)). Consequently, the consumption of C. carpio from Rawal Lake on regular basis was considered unsafe.