Phytoremediation of heavy metal: Principles and prespectives

Acute and diffuse contamination of soil and water by heavy metals and metalloids cause wide, environmental and social concern. Among the techniques used to cleanup affected sites, phytoremediation has recently emerged as a new tool which is cost-effective as well as environment-friendly alternative. After a short introduction to the types of plant-based cleanup techniques, this review focuses on metal hyper accumulator plants and their potential use in phytoextraction technology. Phytoextraction using hyper accumulating plants is seen as a promising technique; a lack of understanding of the basic physiological, biochemical, and molecular mechanisms involved in the removal of heavy metal from environment. The discovery of hyper accumulator plants, which contain high levels of heavy metals that would be highly toxic to other plants, prompted the idea of using certain plant species to extract metals from the soil and, in the process, clean up soil for other less tolerant plants. The best-long term strategy for improving phytoextraction is therefore to understand and exploit the biological processes involved in metal acquisition, transport and shoot in plants.