An Ecological Approach to the Rehabilitation of Bauxite Residue

Bauxite residues can pose an environmental risk mainly because of their alkaline nature and the presence of trace elements. Phytostabilization seems to be a promising rehabilitation option and physicochemical assessment remains the primary indicator of rehabilitation success. To further understand the potential for rehabilitated residues to support both vegetation and soil faunal communities, a series of ex situ exposure tests was conducted. Plant germination, seedling development and trace element uptake were assessed using the Phyto-toxkit (TM) approach. Avoidance and survival tests soil faunal species Eisenia foetida, Folsomia candida and Allobophora chlorotica were conducted to determine possibility of inhibition in residue soils. Unamended residue is inhibitory to plant growth and mesofaunal establishment. Amendment improves the physicochemical properties of the residue, and data revealed that both gypsum and organic addition is required to promote conditions favourable to plant growth and mesofauna establishment.