Risk Assessment on Heavy Metals in Sediments of Rivers Flowing into Miyun Reservoir

In order to understand the potential heavy metal pollution risk levels,six sediments were sampled in Chao River and Bai River and the concentrations of Cu,Zn,Pb,Cr and Cd in the samples were determined.Based on the analysis,a comprehensive assessment on heavy metals in the sediments was presented using index of geo-accumulation and Hakanson potential ecological risks index.The results indicate that,based on the geo-accumulation index,the risk levels of the heavy metal in the area rank as CdCrCuZnPb.Based on the single heavy metal ecological risk index,the risk levels of Cu,Pb,Zn and Cr belong to level,while the risk level of Cr is a bit serious.The risk order of the heavy metals is CdCuCrPbZn.According to the Hakanson potential ecological risk index,Tang River in Huairou is of the middle level;Chao River,Bai River and Hei River are of the slight level.