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

摘要

Heavy metals areelements that are naturally present in the environment. Howeveranthropogenic activities such as the production of industrial wastesand domestic effluents, dumping of sewage waste, urban storm, waterrunoff, and atmospheric sources can give rise to the concentration ofthese metals relative to the normal background values. Any metal ormetalloid 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 lowconcentrations. Some of the heavy metals such as zinc, iron and copperare essential for the physiological functioning of living organisms.The same essential elements become toxic when their concentrationincreases from their initial value. The present review article featuresthe occurrence and toxicity of various heavy metals and compiles thesources, effects and the treatment of heavy metals with reference tocadmium, chromium and lead. This work also investigates the abilitiesof plants in terms of tolerance and degradation of these metals. Italso reviews deeply about the heavy metal uptake mechanisms and severalresearch studies associated with the topics. An evaluation of thepresent status of technology exploitation and the capability of somecultivated plants to reduce the contaminant is also reported andsuggested for future work.