Phytoremediation: A Modern Approach

Introduction

Heavy metal contamination of soil is a global problem due to its negative impact on every component of the ecosystem, threatening the health of vegetation, wildlife and human beings. Bioavailability and bioaccumulation of different heavy metals in aquatic and terrestrial ecosystem are of tremendous global significance as they mainly accumulate in the soil, ground and bottom sediments of seas and oceans and have a long term effect on the biotic factor of this world. There is an absolute need of affordable, environment friendly and sustainable technological solution. Now a day’s chemical decontamination of agricultural lands are getting replaced by ecofriendly bioremediation process. Phytoremediation is the foremost attribute of bioremediation. Phytoremediation is an eco-friendly and cost-effective technology for the remediation of heavy metal contaminated soil and water through implication of plants ability to accumulate heavy metals in their harvestable shoot parts. The prerequisite of phytoremediation is identification of native heavy metal tolerant plants with metal tolerance and detoxification capacity and considerable amount of metal uptake as well as accumulation potentiality. By bioremediation any metal contaminated land of India can be converted into agricultural land.

Heavy metals interfere and affect biochemical and physiological processes such as photosynthesis, respiration, cell elongation, plant water relationship, nitrogen metabolism and mineral nutrition. Heavy metal induced soil pollution is anthropogenic in origin, such as by the residues of metalliferous mining technology, heavy automobile traffic, smelters, household and industrial wastes (Clement et al. 2007). Depending on the type of industries in the vicinity agricultural lands get contaminated with different metals of no biological roles such as As, Cd, Cr, Pb, Ni etc are deposited in the soil. Among these metals, Cd and Cr are the two most important toxic pollutants affecting both animal and plant physiology extremely. Having maximum industrial usage, Cd and Cr pollution of soil and water is an alarming problem in urban and semi urban areas of India and is of international concern also (Bah et al. 2011). Heavy metal exposure occurs significantly by occupational exposure. As these two metals are higly used in industries (tanning, electroplating, mineral fertilizers, Ni- Cd battery production, paints used for glass and ceramics, soft drink plants) almost 65% of industrial workers and local people living in the close vicinity of these industrial areas are regularly exposed to the hazards of these two toxic metals (Sethi et al. 2006). India, being a third world country, here acute emphasis has been given to the development of industrial hub for the employment of huge population. But the protection and restoration of the environment has not been given same importance or weight age and is almost overlooked.