Potentially toxic elements contamination in water and evaluation for risk assessment in the Rawalpindi, Pakistan

This study examined the groundwater and surface water quality for drinking and irrigation purposes in the Rawalpindi, Pakistan. For this purpose, samples were collected from groundwater (n = 30), surface water (River Soan, n = 27) and wastewater (n = 21). Each sample was analyzed for the physiochemical parameters and potentially toxic elements (PTE) concentrations. Results revealed that groundwater showed the lowest levels of physiochemical parameters and PTE contaminations, followed by the surface water (River Soan) and the highest in wastewater. The PTE contamination's levels in groundwater, River Soan and wastewater surpassed the national environmental quality standards (NEQs) set by Pakistan's environmental protection agency (Pak EPA). Groundwater (hand pump, bore well and tube well) sources were evaluated for the risk assessment of PTE consumption through drinking water. Among drinking water, the highest PTE contaminations were observed in hand pump water that led to higher average daily intake (ADI) (0.079 mg/kg-d) value for Zn and hazard quotient (HQ) value (11.7) for Cd. The HQ values of Cd were > 1 for all sources of drinking water. Higher HQ values of Cd could induce various acute and chronic health problems to exposed human population of study area.