The Spatial and Temporal Variation Characteristics and Potential Ecological Risk Assessment of Heavy Metal Pollution in Surface Sediments of Chaohu,China

Based on the monitoring of six heavy metal elements(Zn,Hg,Cr,Pb,Ni and Cu)in the surface sediments from eight samples sites of Chaohu from March to July in 2008,temporal and spatial variation characteristics and contamination degree of heavy metal pollution was discussed,and their potential ecological risk and key ecological risk indexes were assessed.The concentrations of heavy metals in the surface sediments of Chaohu reduced gradually during investigation period.The contamination in the inflow lake region was higher than others.Zn,Cu and Pb were the main contaminants compared with other heavy metals.Heavy metal pollution from 12 cm depth surface sediments became aggravated with depth increasing.In addition,the surface sediments from Chaohu appeared slight potential ecological risk,and the first two regions were Nanfei inflow rive area and Shiwuli inflow river area.The potential ecological risk levels of heavy metals reduced gradually from March to July.The result also showed that the main factors influencing ecological safety in Chaohu were Hg,Pb and Cu.