Heavy metals accumulation in plants growing in ex tin mining catchment

Acid mine drainage (AMD) causes environmental pollution that affects many countries having historic or current mining industries. Preventing the formation or the migration of AMD from its source is generally considered to be the preferable option, although this is not feasible in many locations, and in such cases, it is necessary to collect, treat, and discharge mine water. There are various options available for remediating AMD, which may be divided into those that use either chemical or biological mechanisms to neutralise AMD and remove metals from solution. Both abiotic and biological systems include those that are classed as "active" (i.e., require continuous inputs of resources to sustain the process) or "passive" (i.e., require relatively little resource input once in operation). This review describes the current abiotic and bioremediative strategies that are currently used to mitigate AMD and compares the strengths and weaknesses of each. New and emerging technologies are also described. In addition, the factors that currently influence the selection of a remediation system, and how these criteria may change in the future, are discussed.

This paper reviews the ecological aspects of mined soil restoration, with special emphasis on maintaining a long-term sustainable vegetation on toxic metal mine sites. The metal mined soils are man-made habitats which are very unstable and will become sources of air and water pollution. Establishment of a vegetation cover is essential to stabilize the bare area and to minimize the pollution problem. In addition to remediate the adverse physical and chemical properties of the sites, the choice of appropriate vegetation will be important. Phytostabilization and phytoextraction are two common phytoremediation techniques in treating metal-contaminated soils, for stabilizing toxic mine spoils, and the removal of toxic metals from the spoils respectively. Soil amendments should be added to aid stabilizing mine spoils, and to enhance metal uptake accordingly.