Yalgado Zakaria Sawadogo¹, Telado Luc Bambara^{1, 2,}, Moumouni Derra^{1, 3}, Inoussa Zongo^{1, 4}, Karim Kaboré^{1, 5}, François Zougmoré¹

This study evaluates the physicochemical characteristics as well as the presence of heavy metals in agricultural soils located near an industrial gold mine in Burkina Faso. To do this, two soil pollution indices were used, namely the geoaccumulation index (Igeo) and the enrichment factor (EF). A total of thirteen (13) soil samples were collected and analysed in the laboratory at the Bureau of Mines and Geology of Burkina Faso (BUMIGEB) using atomic absorption spectrometry (AAS) to determine the concentrations of Hg, As, Pb, Cr, Zn, Cu, Ni and Al. The physicochemical parameters were analysed at the National Soils Office (BUNASOL). The results indicate that the studied soils have high acidity, marked salinity, silty texture, as well as a satisfactory C/N ratio. Concentrations of Hg, As, Cu and Cr were found to be higher than average continental crust values. In addition, the concentrations of Hg and As exceed South African standards, while Hg also exceeds the standards set by WHO and FAO. The use of the Igeo and FE indices made it possible to demonstrate that the studied area was highly enriched in mercury, significantly enriched in arsenic and weakly to moderately enriched in copper, which suggests an influence of human activities. Arsenic seems to come mainly from mining activities, while mercury comes from both mining and agricultural activities.

heavy metals, concentration, geoaccumulation, pollution, enrichment factor, physico-chemical parameters