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,

The purpose of this study was to survey the distribution patterns of volatile organic compounds (VOCs) and formaldehyde in the various indoor environments using cluster analysis. We investigated VOCs and formaldehyde in subway stations, underground shopping areas, medical centers, maternity recuperation centers, public childcare centers, large stores, funeral homes, and indoor parking lots from June 2005 to May 2006 (9 p.m. to 6 a.m.). The concentration of total volatile compounds (TVOCs) in maternity recuperations was 2,605.7 μg/m 3 , which was higher than that stated in the guideline and other chosen facilities. TVOCs in public childcare centers were 1,951.6 μg/m 3 , which also exceeded the guideline. Moreover, the concentration of TVOCs in every facility exceeded the guideline of the Ministry of Environment, Korea. In the case of formaldehyde, the mean concentration of 336.5 μg/m 3 found only in public childcare centers exceeded the 120 μg/m 3 stated in the guideline. Finally, by applying cluster analysis, three patterns of the indoor air pollutions were distinguished. In the results of the analysis, concentrations of TVOCs and formaldehyde of cluster 3 were higher than clusters 1 and 2, which were 2,561.4 and 184.9 μg/m 3 , respectively.

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