Remediation of soil contaminated with Mn, Cu and Zn around the Mbembele mine in Gabon: Phytoremediation approach (Vetiveria zizanioides and Phacelurus gabonensis)

Abstract

The ability of Vetiveria zizanioides and Phacelurus gabonensis to accumulate copper (Cu), zinc (Zn) and manganese (Mn) in the aerial parts and to mobilise them in the roots is applied. This investigation is based on the in situ observation of these plants, their biomass and the evaluation of the translocation capacity of each metal from roots to aerial parts. A proliferation of both plants in culture was observed for three months, then harvested and analysed. Significant metal contents, on 250 mg of samples taken, are observed in the aerial parts of Phacelurus gabonensis (2028 ppm of Cu, 9 ppm of Zn and 7456 ppm of Mn) whereas (3854 ppm Cu, 268 ppm Zn 43005 ppm of Mn) in the roots. Vetiveria zizanioides records in the aerial parts 83 ppm Cu, 31 ppm Zn and 8761 ppm, Mn while in the roots there are 83 pm Cu, 1974 ppm Zn and 11930 ppm Mn. The ability to transfer these metals from the roots to the aerial parts is greater in Vetiveria zizanioides than in Phacelurus gabonensis despite the high metal concentrations in the aerial parts in Phacelurus gabonensis.The high concentrations of metals purified by Phacelurus gabonensis and Vetiveria zizanioides place them among the top ranks of phytoremediation.