Article

Heavy metals, occurrence and toxicity for plants: a review

Environmental Chemistry Letters (Impact Factor: 1.91). 09/2010; 8(3):199-216. DOI: 10.1007/s10311-010-0297-8

ABSTRACT Metal contamination issues are becoming increasingly common in India and elsewhere, with many documented cases of metal toxicity
in mining industries, foundries, smelters, coal-burning power plants and agriculture. Heavy metals, such as cadmium, copper,
lead, chromium and mercury are major environmental pollutants, particularly in areas with high anthropogenic pressure. Heavy
metal accumulation in soils is of concern in agricultural production due to the adverse effects on food safety and marketability,
crop growth due to phytotoxicity, and environmental health of soil organisms. The influence of plants and their metabolic
activities affects the geological and biological redistribution of heavy metals through pollution of the air, water and soil.
This article details the range of heavy metals, their occurrence and toxicity for plants. Metal toxicity has high impact and
relevance to plants and consequently it affects the ecosystem, where the plants form an integral component. Plants growing
in metal-polluted sites exhibit altered metabolism, growth reduction, lower biomass production and metal accumulation. Various
physiological and biochemical processes in plants are affected by metals. The contemporary investigations into toxicity and
tolerance in metal-stressed plants are prompted by the growing metal pollution in the environment. A few metals, including
copper, manganese, cobalt, zinc and chromium are, however, essential to plant metabolism in trace amounts. It is only when
metals are present in bioavailable forms and at excessive levels, they have the potential to become toxic to plants. This
review focuses mainly on zinc, cadmium, copper, mercury, chromium, lead, arsenic, cobalt, nickel, manganese and iron.

KeywordsHeavy metals-Environment-Toxic effects-Plants-Anthropogenic activities

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