Risks associated with the mining of Pb-Zn minerals in some parts of the Southern Benue trough, Nigeria.

The environmental effects of the mining of lead-zinc mineralization in Enyigba area, Southern Benue trough were examined. The samples used for this study were obtained from abandoned mine sites, mine tailings, streams, hand-dug wells, mine pond and borehole. Collected samples were subjected to X-ray fluorescence, X-ray diffraction analyses, atomic absorption spectrometry and permeability tests. These were done using standard laboratory equipment and procedures. The concentrations of heavy metals present in analysed water samples fall below the world health organizations' (WHO) acceptable limits. Conversely, the soil, mine tailings and stream sediments indicate appreciable pollution level by some potential toxic metals (PTMs). Consequently, the habitual use of these soils for construction purpose by inhabitants has possible health hazards. The shaly lithology underlying the area is increasingly affected by weathering and lateritization, thus improving its permeability and the easiness with which PTMs can be conducted to the water table by leachate. Regular monitoring assessment is recommended to ensure adherence of miners operating in the area to existing environmental laws.