Impacts of artisanal and small-scale gold mining on soils in northern regions of Côte d’Ivoire: cases of Boundiali, Korhogo and Tengrela

Abstract

The development artisanal and small-scale gold mining in recent years in Côte d'Ivoire could pose a risk to soils and health of local communities. This study aimed at assessing the impacts of artisanal and small-scale gold mining on the soils in the areas in the northen localities (Boundiali, Korhogo and Tengrela) of Côte d’Ivoire, where those activities are accentuated. Field observation and physico-chemical parameters analysis (potential hydrogen (pH), cation exchange capacity (CEC), organic matter (OM)) and pollutants (mercury (Hg), copper (Cu), zinc (Zn), arsenic (As) and cyanide (CN)) in soil samples were carried out. The results indicate that artisanal gold mining create soils erosion and consequently, soil structure destruction. Trace metals concentrations were 0.0001-0.0051 mg/kg (Hg), 0.002-0.32 mg/kg (CN), 18.90-73.10 mg/kg (Cu), 16.40-50.1 mg/kg (As) and 10.20-26.60 mg/kg (Zn). Geoaccumulation index (Igeo) in soils showed uncontamination for Hg and Zn, uncontamination to moderate contamination for Cu and moderate to strong contamination for As. According to ecological risk index (Eri), As could pose considerable to high risks to biota in study area. This study highlights serious risks to soil biota and human health, from artisanal gold mining activities. Thus, it is necessary to clean-up arsenic-contaminated soils.