Effect of Mining on Heavy Metals Toxicity and Health Risk in Selected Rivers of Ghana

Heavy metal contamination of selected rivers in the mining areas of Ghana was studied. In the study, 44 composite water samples were collected, digested, and analyzed for selected metals using ICP-MS. The average concentrations (mg/L) of heavy metals from the pristine sites ranged from 0.003 (As) to 0.929 (Fe), and the mining sites ranged from 0.002 (Pb) to 20.355 (Fe). Generally, the metals were within the WHO and USEPA acceptable limits except Al, Fe, As, Cr, and Mn. Hazard quotients for ingestion (HQing) and dermal contact from pristine and mining sites ranged from 0.838 (Cr) to 3.00 × 10−4 (Cu) and from 0.181 (As) to 2.40 × 10−6 (Cu), respectively. The carcinogenic risks (CRs) for ingestion were within standard limit (10−6 to 10−4). However, Arsenic showed high CRing above the acceptable limit (1.83 × 10−2). The CRs for dermal contact range from 4.22 x 10−8 to 1.44 x 10−9 (Cr) and from 7.34 x 10−8 to 5.65 x 10−9 (Pb). Carcinogenic risk values for As in the mining areas raise carcinogenic concerns for the residents in the studied areas. PROMETHEE and GAIA indicate major contribution of the metals from the mining. Multivariate PCA and cluster analysis suggest anthropogenic activities as the major source of the metal toxicity of the mine rivers