Assessment of Metal Enrichment in the Koma Bangou (Niger) Gold Panning Area Soils and Tailings

Artisanal and small-scale gold mining at Koma Bangou (Niger) has been going on since the Sahelian 1984’s drought, with introduction of ore leaching in the year 2009. The use of chemicals in the ore processing results in metal enrichment and pollution at the cyanidation sites. The aim of this work is to assess the metal enrichment of soils and tailings at Koma Bangou. Geochemical data acquired with portable XRF analyzer corrected with ICP-MS data, were used to assess the enrichment level of As, Cr, Cu, Mn, Pb and Zn in the soils and tailings samples using the enrichment factor and soil-geochemical baseline data for the Koma Bangou soils. The metallic enrichment generated by the ore processing was identified in the tailings (cyanidation and acidification waste) and the soils from the cyanidation areas. The perimeter soils (soils outside cyanidation sites) show no metal enrichment. Pb and As are extremely high to very high enriched in the cyanidation waste, with an average enrichment factor value of 44.96 and 34.96 respectively. Zn, Cu, Cr are extremely high to significant enriched in the acidification waste, with an average enrichment factor value of 793.35, 29.46 and 5.22 respectively. Mn enrichment is insignificant in all of the samples with an average enrichment factor value of 1.00 in the perimeter soils. The gold ore leaching activities generate metallic pollution of the soil, water and vegetation around the cyanidation sites.