Characterization, source apportionment and health risk assessment of trace metals in freshwater Rawal Lake, Pakistan

Abstract

Water quality of freshwater reservoirs in Pakistan is being degraded because of excessive anthropogenic activities. There is a dire need for appropriate water quality monitoring and evaluation of related health risks to humans. The distribution of trace metals (Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb, Sr and Zn) was evaluated in the surface water of Rawal Lake, Pakistan by atomic absorption spectrometry along with the physicochemical parameters during summer and winter. Multivariate methods were used for identification and apportionment of the pollution sources in the lake. Non-carcinogenic health risk assessment was computed to assess the adverse health effects on the population. During summer, average metal levels in the water samples exhibited decreasing concentration order: Na>Ca>Mg>K>Sr>Pb>Fe>Zn>Co>Cu>Cr>Cd=Li>Mn, while during winter, the order was: Ca>Na>Mg>K>Sr>Pb>Co>Cr>Fe>Cd>Zn>Cu>Mn>Li. Among the metals, measured levels of Cd and Pb during summer and winter, while that of Co and Cr during winter were found to be higher than the guideline values. Multivariate PCA and CA revealed significant anthropogenic contributions of the metals in lake water. The hazard quotients (via ingestion) of Cd and Pb during summer as well as in winter, whereas, that of Cr and Co during winter were found to be higher than the safe limits, posing threat to the consumers. However, no risk related to the dermal contact was associated with the measured metal levels.