Heavy Metal Concentrations and Ecological Risk Assessment of the Mine Tailings around Moanda Manganese Mining areas of Gabon

This study aimed to assess the concentrations of trace elements and the associated ecological risk in tailings collected around the manganese mining area of Moanda in Gabon. The contents of trace elements in the mining tailing samples determined using the XRF analysis were significantly higher than their average concentrations in the upper continental crust (UCC), indicating a polymetallic contamination in the following order: Mn>Cu>Zn>Ni>Co>Cr>Pb>Zn. The Mn more concentrated in tailing samples would accumulate in the edible parts of plants cultivated around the manganese mine of Moanda. The values of geoaccumulation index (Igeo) and contamination factor (CF) indicate a moderate contamination in Co, Cu, and Cr, and a high contamination by Mn, Cu, Ni, and As. Results indicate a very high ecological risk (Ri) to the local biocenosis. These results highlight the need to implement strategies to mitigate environmental impacts and develop systems to protect local ecosystems and communities from the adverse effects of mining activities in the region of Moanda.