Résumé
In Côte d’Ivoire, despite an intense development of artisanal and small-scale gold mining (ASGM) activities in thelast two decades, the environmental impacts of this activity are poorly documented. This study aimed to documentthe concentrations of geogenic and exogenous contaminants potentially released by ASGM (metals and cyanides) indifferent sources (ore, mining wastes) and environmental compartments (soils, surface and ground waters, sediments) inthe Kokumbo area, part of the Au-rich Birimian greenstone belt. Alluvial ore material is enriched in various metal(oid)s (As, Co, Cu, Cr, Fe, Mn, Ni, Sb, and V) compared to the average composition of the upper continental crust whileother metals (Cd, Pb, Ti, Zn) show no geochemical anomalies. High Hg concentrations were found in cyanidationresidues (up to 8.32 mg/kg) and sediments (up to 20.4 mg/kg) compared to unprocessed alluvial ores (0.06 ± 0.01 mg/kg) indicating that Hg used in amalgamation is the source of Hg contamination. Cyanidation residues contain up to100 mg/kg of total cyanides but generally less than 3% are in the form of free cyanides, the most mobile and toxicform. Arsenic concentrations in water are low (< 2.5 μg/L) despite its relatively high content in sediments and soils(76 ± 54 mg/kg), showing a low mobility of As, likely due to its adsorption on iron oxy(hydr)oxides. Apart from Mn,metals have low dissolved concentrations in water except in a stream draining a cyanidation site suggesting that thecyanidation effluent discharge may contribute to metal dispersion in rivers.