Groundwater vulnerability to artisanal gold mining pollution: a modified DRASTIC-GIS framework for Siguiri, Republic of Guinea

The uncontrolled expansion of gold mining operations and unplanned urban development has triggered a global groundwater contamination crisis. Nowhere is this more apparent than in Guinea’s Siguiri Prefecture, where artisanal and industrial mining have severely polluted local aquifers. Toxic waste from improper mining practices – including mercury and cyanide residues – continues to infiltrate shallow groundwater supplies, creating widespread risks to drinking water and public health while exposing critical gaps in environmental regulation. This study assesses groundwater vulnerability in Siguiri Prefecture using a GIS-based modified DRASTIC model, aiming to provide a goal-oriented framework for mitigating pollution risks and protecting groundwater resources. Integration of remote sensing satellite imagery, climatic records, hydrogeological drilling data, statistical analysis, and spatial analysis tools was employed to generate a comprehensive database. This database facilitated a multidisciplinary framework to produce a thematic groundwater vulnerability map, validated using bicarbonate (HCO3−) and Arsenic (As) concentrations from groundwater samples. The results reveal that approximately 12% of the area exhibits very high groundwater vulnerability, while 20% shows high vulnerability, indicating uncertain hydrogeological protection. The applied approach deepens the understanding of aquifer vulnerability to wastewater from gold mining, providing actionable insights for stakeholders.