Assessment of soil quality in mining areas: Cross-analysis of environmental impact assessment (EIA) and field data in Kedougou, Senegal

Soil contamination remains a critical yet often underestimated challenge in environmental impact assessments (EIAs) of mining projects in West Africa. This study assessed soil quality across 37 industrial and artisanal gold mining sites in the Kédougou region of Senegal. A Mining Soil Quality Index (MSQI) was developed, integrating heavy metal concentrations (As, Pb, Hg, etc.) with international and regional reference thresholds. Combined with a strategic land-use and vulnerability zoning framework, the analysis revealed widespread contamination, with nearly half (45%) of artisanal sites categorized as high-risk zones. The evaluation also exposed major inconsistencies in EIA datasets, including outdated baseline measurements, poor comparability across reports, and a lack of methodological standardization. These findings underscore the urgent need to institutionalize systematic soil monitoring programs, adopt harmonized assessment frameworks across West Africa, and integrate soil quality into Strategic Environmental Assessment (SEA) processes.