Potentially harmful elements contamination in water and sediment: Evaluation for risk assessment and provenance in the northern Sulaiman fold belt, Baluchistan, Pakistan

This study was aimed to investigate the potentially harmful elements (PHE) contamination and provenance in water and sediments of Zhob and Loralai valleys, northern Sulaiman fold belt (SFB), Baluchistan province, Pakistan. For this purpose, groundwater (springs, dug wells, bore wells and tube wells), surface water (Zhob River, Loralai River and tributaries) and sediments samples were collected and analyzed for physicochemical parameters including PHE. The concentrations of PHE including iron (Fe2+), nickel (Ni2+), lead (Pb2+), cobalt (Co2+), chromium (Cr3+) and cadmium (Cd2+) surpassed the world health organization (WHO) drinking water guidelines in 71%, 76%, 71%, 57%, 67% and 45% of samples in Zhob valley, respectively. Determined PHE concentrations in drinking water were evaluated for the potential risk assessment through average daily intake (ADI) and hazard quotient (HQ). Among PHE, the highest mean (0.12 mg/kg-day) ADI values were noted for Fe2+ and HQ for Cr3+ (1.95), surpassed the safe threshold limit in Zhob valley. Highest contamination factor (CF) values were found for Fe2+, Mn2+, Ni2+, Cu2+, Co2+, Cr(3+)and Cd2+ in Zhob valley, while Zn and Pb in Loralai valley. Statistical analysis such as inter-metals correlation, one-way ANOVA and principal component analysis (PCA) showed that major sources of PHE contamination are geogenic.