Heavy Metal Pollution in Surface Sediment of Urban River in Chaohu City and Its Risk Assessment

Abstract:

Nine surface sediments were collected from urban rivers of Chaohu City, China, for an analysis of 7 heavy metals (Hg, Cu, Pb, Zn, Cr, Ni and As). A comprehensive way was conducted to investigate distribution patterns and assess the potential ecological risks of heavy metals. The results indicate that the sediments are severely contaminated by heavy metals and mean concentrations of Hg and As are above PEL values. The contamination order of the 7 metals is Ni, Hg, Cu, As, Cr, Zn, Pb according to the mean Igeo values, while the single potential ecological risk of heavy metals followes the order Hg, As, Cu, Pb, Cr, Ni, Zn. The element Ni was the main pollutant and Hg was the second most abundant element with the most serious ecological risks. More attention was demanded to the metalloid As in ecological risk assessments. The pollution of the remaining 4 metals was slight with little ecological risk. The distribution pattern of Hg individual potential ecological risk indices was similar to that of the general potential ecological risk indices for all metals. More concern should be focused to West Huancheng River suffering serious ecological risk.

Key words:urban river; sediment; heavy metal; risk assessment