Potentially Toxic Metals and Biological Contamination in Drinking Water Sources in Chromite Mining-Impacted Areas of Pakistan: A Comparative Study

Abstract

Water quality and quantity are the major environmental concerns of developing countries like Pakistan. Safe drinking water is one of the major prerequisites for a healthy life. The current study assessed the contamination of drinking water including physicochemical parameters (pH, TDS, EC, TH, Cl1−, NO3 1−, PO4 3−, SO4 2−, Mn, Cd, Pb, Ni, Cr) and bacteriological contamination (Fecal coliform) in chromite mining-impacted areas of Pakistan. However, the main focus of the study was to identify the potential health risk of these parameters to the local people of the study area. Atomic Absorption Spectrometer (Perkin Elmer, AAS-PEA-700) was used to analyze the concentrations of potentially toxic metals. The concentrations of Cd, Pb, Ni, and Cr ranged from below detection limit (BDL)-7.20, BDL-14.4, BDL-78.3 and 0.20–69.0 and exceeded their respective limits in 31, 11, 17, and 36% samples of drinking water set by World Health Organization, while the concentration of Ni (63% samples) also exceeded the safe limit set by Pakistan Environmental Protection Agency. Furthermore, the chronic daily intake (CDI) and health risk index (HRI) of potentially toxic metals through consumption of drinking water were found in the order of Mn > Ni > Cr > Cd > Pb and Cd > Ni > Mn > Pb > Cr, respectively. The HRI values of selected toxic metals in mining-impacted sites were found within the safe limit (HRI <1). The results showed that both geogenic and anthropogenic activities were the main sources of drinking water contamination in the study area.