Phytoremediation of metal mine waste.

Abstract

Phytoremediation is a group of technologies that us e plants to reduce, degrade, or immobilize environmental toxins, primarily those of anthropoge nic origin, with the aim to clean-up contaminated areas. In this review paper, different types of phy toremediation processes, typical plants used and th eir application for clean-up of metal contaminated site s were reviewed. Plant responses to heavy metals an d mechanisms of metal uptake and transport were also discussed. Phytoremediation of Pb, Zn, Cu and Fe tailings and mine spoils were carried out by grasse s, herbs and shrubs, which could be categorised as As accumulator ( Paspalum , Eriochloa, Holcus, Pennisetum Juncus, Scirpus and Thymus), Pb accumulator (Brassica juncea, Vetiveria, Sesbania, Minuartia, J uncus, Scirpus and Thymus), Cu accumulator (Ammania baccifera, Scleranthus) Zn and Cd accumulator (Vetiveria, Sesbania, Viola, Sedum, Rumex). The research work showed that, bioavailability and metal uptake by plants could be accomplished by ameliorating pH, addition of organic amendment, fer tiliser and chelating agents. Further research is required to develop fast growing high biomass plant s with improved metal uptake ability, increased translocation and tolerance of metals through genet ic engineering for effective phytoremediation of me tal mine wastes.