Assessment of physico-chemical water parameters and health risk characterization in the mining areas of Siguiri, Guinea

Artisanal and small-scale gold mining (ASGM) represents a crucial socio-economic activity in many low- and middle-income countries yet poses significant environmental and public health threats due to unregulated practices. This study assessed water contamination and associated health risks in the ASGM areas of Siguiri, Guinea. We collected 36 water samples (12 boreholes, 24 river points) from three major mining sites during dry (April) and rainy (August) seasons. Samples were analyzed for eight heavy metals (mercury, lead, aluminium, cadmium, nickel, manganese, copper, iron) using UV-visible spectrophotometry. Health risk assessment followed USEPA methodology, including hazard identification, exposure, toxicity assessment, and risk characterization. We computed hazard indices and carcinogenic risk for adults and children. Multivariate statistical analyses identified contamination patterns and vulnerable populations. Heavy metal concentrations exceeded WHO guidelines, particularly during rains. River water showed higher contamination than borehole water, Nickel and manganese exceeded limits by 10-20 fold, while mercury and lead surpassed limits by >50-fold at some sites. Water hazard index peaked at 56.3. Non-carcinogenic ingestion risks for children reached alarming values of 476 (dry season) and 409 (rainy season) far exceeding the acceptable risk threshold of 1. Dermal exposure posed negligible risks compared to ingestion (HIderm < 0.01). Carcinogenic risks exceeded EPA thresholds (>10⁻4) for nickel, lead, and cadmium, with children being 4-10 times more vulnerable than adults. Multivariate analysis identified three contamination clusters: "Low Toxicity (Dry Season)," "Moderate Toxicity (Rainy Season)," and "High Toxicity (Oudoula)." Our findings demonstrate significant health risks, particularly for children, necessitating urgent interventions. We recommend installation of low-cost water treatment systems, buffer zones around mining sites, tailings containment structures and phytoremediation using local metal-accumulating plants. These measures align with SDGs 3, 6, and 12, supporting Guinea's national development agenda while protecting vulnerable communities from mining-related health hazards.