Assessment of Groundwater Quality and Exposure Risks in a Rural Mining District of Ghana Using Multivariate and Probabilistic Approaches

This study investigates the hydrogeochemical characteristics and human health risks associated with groundwater in Artisanal and Small-Scale Gold Mining (ASGM) zones within the Talensi District of northern Ghana. A total of 35 borehole samples were analysed for physicochemical parameters and potentially toxic elements (PTEs), with groundwater quality evaluated using the Weighted Average Water Quality Index (WAWQI) and Heavy Metal Evaluation Index (HEI). Multivariate statistical techniques, including Principal Component Analysis (PCA) and Self-Organizing Maps (SOM), were employed to delineate underlying geochemical processes and apportion pollution sources. Additionally, deterministic and probabilistic Human Health Risk Assessments (HHRA) were conducted for both adults and children through ingestion and dermal exposure pathways. Results indicate that groundwater across the district is generally suitable for drinking, with 100% of samples falling within ‘excellent’ to ‘good’ WAWQI categories (16.11–34.62; mean = 25.51; SD = 5.41) and HEI values (1.70–7.51; mean = 4.65; SD = 1.36) signifying low pollution levels. However, spatial heterogeneity was observed, with localized enrichment of As, Hg, and Cu linked to ASGM activities. PCA and SOM revealed distinct geochemical clusters dominated by anthropogenic inputs (As, Hg, Cu) and geogenic signatures (Ni, Zn, Pb). HHRA indicated no significant risk for adults (HI < 1; mean = 0.23), but some risk for children in isolated locations (HI > 1; mean = 0.84). The findings underscore a dual geogenic–anthropogenic influence on groundwater chemistry in Talensi and point to the need for targeted water quality monitoring and pollution control in mining-impacted zones.