REVIEW

Effect of Heavy Metals on Growth and Development of Cultivated Plants with Reference to Cadmium, Chromium and Lead – A Review

Heavy metals are elements that are naturally present in the environment. However anthropogenic activities such as the production of industrial wastes and domestic effluents, dumping of sewage waste, urban storm, water runoff, and atmospheric sources can give rise to the concentration of these metals relative to the normal background values. Any metal or metalloid with a density exceeding 5g /cm−3 is termed as “heavy metal”. These metallic ions are always associated with pollution and toxicity, although some of these elements are required by organisms at low concentrations. Some of the heavy metals such as zinc, iron and copper are essential for the physiological functioning of living organisms. The same essential elements become toxic when their concentration increases from their initial value. The present review article features the occurrence and toxicity of various heavy metals and compiles the sources, effects and the treatment of heavy metals with reference to cadmium, chromium and lead. This work also investigates the abilities of plants in terms of tolerance and degradation of these metals. It also reviews deeply about the heavy metal uptake mechanisms and several research studies associated with the topics. An evaluation of the present status of technology exploitation and the capability of some cultivated plants to reduce the contaminant is also reported and suggested for future work.