Groundwater quality, pollution sources, and health risk assessment in a mining-dominated district: A case study from Atiwa West, Ghana

This study examined groundwater hydrogeochemistry, pollution sources, and health risks in the mining-dominated Atiwa West District of Ghana using 56 borehole and well samples collected in dry and wet seasons. Electrical conductivity and total dissolved solids ranged from 67.2 to 692 μS/cm and 33.6–389 mg/L, respectively, classifying the water as fresh. Iron (mean 2.05 mg/L, wet) and manganese (mean 0.33 mg/L, wet) exceeded WHO aesthetic limits, while arsenic (max 0.006 mg/L) and mercury (max 0.002 mg/L) approached guideline values. Principal Component Analysis explained over 80 % of variance, linking carbonate weathering, redox mobilization of Fe–Mn, and sulphide oxidation as key geochemical controls, with anthropogenic contributions evident in wet-season recharge. Saturation index modeling showed persistent undersaturation of evaporite minerals (gypsum, halite, sylvite), indicating active dissolution, while carbonate minerals (calcite, aragonite, dolomite) were near equilibrium to supersaturated, reflecting their buffering role in aquifers. Water Quality Index (WQI) ranged from excellent (<25) to very poor (>200), with deteriorated quality more common near mining and agricultural zones in the wet season. HHRA results indicate that most risks remain within acceptable limits, though non-carcinogenic HI exceedances reached 3.97 percent in adults and 7.66 percent in children during the dry season, declining to 2.43 percent and 4.83 percent in the wet season. Cancer risk exceedances affected 8.02 percent of adults and 12.69 percent of children in the dry season, reducing to 5.60 percent and 9.26 percent in the wet season, with Mn and Cu as the dominant contributors to non-carcinogenic risk.