Hydro-environmental risk assessment of heavy metal pollution in the groundwater and river water of the Amaravati Basin, Southern India

Human health requires safe and clean drinking water, but urbanization and industrialization have led to increased heavy metal release into water systems. In this study, the concentration, contamination status, and health risks of heavy metals in groundwater and river water from the Amaravati River Basin, South India, were investigated. Thirty samples were analyzed for Fe, Zn, Pb, Cr, Cu, Mn, Ni, Cd, and Co. Groundwater contained high mean concentrations of Cd (1.151 mg/L), Cr (0.907 mg/L), and Pb (1.546 mg/L), all exceeding safe drinking water limits, while Cd (1.493 mg/L), Cr (0.777 mg/L), and Pb (0.549 mg/L) remained high in river water, largely because of runoff and sediment transport. Heavy metal pollution indices (HPI, HEI, and DOC) suggested serious pollution, with groundwater showing higher overall pollution levels. Non-carcinogenic risk assessment showed hazard index (HI) values greater than 1 for all age groups (2.252 for infants in groundwater and 2.439 for infants in river water, 4.985 for children in groundwater and 5.401 for children in river water), suggesting potential long-term health effects. The metal enrichment is primarily caused by natural weathering and rock–water interaction in granite gneiss and charnockite formations, and exacerbated by human activities. The findings highlight the importance of ongoing monitoring and mitigation measures to ensure the safety of drinking water in the Amaravati River Basin.