Bioremediation Of Heavy Metal Toxicity-With Special Reference To Chromium

All metals are toxic and our bodies require special transport and handling mechanisms to keep them from harming us. The toxicity occurs in humans due to environmental pollution via soil or water contamination or due to occupational exposure. Some of these metals are useful to us in low concentrations but are highly toxic in higher concentrations. These metal toxicity cause serious morbidity and mortality. Among these heavy metals chromium toxicity can cause serious carcinogenic, genotoxic and immunotoxic effects in humans and animals. Of the two oxidative states in which chromium can be present Cr (III) and Cr (VI), Cr (III) is essential for the human system whereas Cr (VI) has harmful effects. So, one of the ways of reducing Cr-toxicity in Cr-contaminated soil and water is to reduce soluble Cr (VI) to insoluble Cr (III). This can be achieved by microbial activity and is a cost-effective and environment friendly method. Many genera of microbes like Bacillus, Enterobacter, Escherichia, Pseudomonas and also some yeasts and fungi help in bioremediation of metals and chromium-contaminated soil and water by bio-absorption and bioaccumulation of chromium. The potential of bioremediation of metal toxicity and its impact on the environment is discussed. Key-words: Metal-toxicity, Chromium-toxicity, Bio-remediation, common effluent treatment