Hydrogeological facies evolution in a mining context: the case of the Kankan aquifer (Guinea)

In the mining areas of the Kankan administrative region (Guinea), access to drinking water is problematic due to population explosion and gold mining, particularly various artisanal and industrial techniques that can cause lasting disruption to water systems. The aim of this study is to assess the physical and chemical quality of drinking water in these mining areas. Nineteen traditional wells and fourteen boreholes were sampled to identify any contamination of these groundwater sources. The analyses reveal the presence of certain trace metals (As, Pb) among the major ions. Of the thirty-three water points analysed, calcium ion concentrations exceed the WHO (World Health Organization) drinking water standard at more than half of the sites (seventeen out of thirty-three water points). With regard to trace metals, arsenic concentrations exceeded the WHO standard by more than seven times in three-quarters of the samples. The same is true for lead, but to a greater extent. Indeed, concentrations of this element are always above the drinking water standard. Furthermore, in three-quarters of the wells and boreholes analysed, the concentrations measured exceeded the standard by a factor of 7. The contamination of these water points by these various chemical elements appears to be linked both to local geological characteristics and to anthropogenic pressures associated with mining and industrial activities. The results of this study show a deterioration in the physical and chemical quality of all the water sources analysed in these mining areas in the Kankan region. Widespread contamination by arsenic and lead, far exceeding WHO drinking water standards, poses a major risk to public health, particularly for the populations that use these water sources.