heavy metal pollution in kabini river sediments

the river kabini which is tributary of cauvery drains through industrial area at nanjangud, karnataka. out of the sediment load carried by the river, 2micron the clay fraction was analyzed for total heavy metal contents and advanced statistical techniques such as cluster analysis and correlation matrix were applied in order to investigate the source of heavy metal concentration in the sediments. the river carries natural and anthropogenic pollutants, mainly heavy metal concentration of cd, cr, cu, fe, mn, ni, pb and zn which are released from industrial effluents, agricultural return flows and domestic sewage. the heavy metals find their residence in the colloidal form in water and in 2micron clay fraction in the river bed sediments. systematic sampling of the river bed sediments at predefined locations has revealed that the metal accumulation is very close to normal and also beyond threshold limits. compared with the maximum background values in kabini river sediment, pb was the highest in terms of contamination level, especially at point of influx of paper mill effluents, followed by zn and cu.