Phytoremediation of Heavy Metals-Enhanced by EDTA:A Review

Soils are extensively contaminated with different type of heavy metals worldwide causing a severe disturbance to living biota of the world. Various types of plants are used to remediate these contaminants from soils that are mostly known as hyper accumulator. Chemically-induced phytoremediation which is based on the fact that the application of certain chemicals, mostly chelating agents, to the soil significantly enhances metal accumulation by plants has been proposed as an alternative for the cleaning up of metal polluted soils. But chelate-induced phytoremediation increases the risk of adverse environmental effects due to metal mobilization during extended periods of time. The low bioavailability of heavy metals in soils and the limited translocation of heavy metals to the shoots by most high biomass producing plant species limit the efficiency of the phytoremediation process. Amendment of a contaminated soil with ethylene diamine tetraacetic acid (EDTA) increases soluble heavy metal concentrations, potentially rendering them more available for plant uptake. This review highlights the effects of EDTA on the uptake of heavy metals and translocation to above ground harvestable plant parts and its behavior in the removal of heavy metals from contaminated soils by means of different plant species.