Analysis of Heavy metal Pollution in the Sediment of the Inflow-lake Rivers of the Hongfeng Lake

Based on the analysis of the contents of 8 heavy metals(Cd, Pb,Cu, Co, Ni, Cr, V, Zn)in the sediments of 4 main inflow-lake rivers of the Hongfeng Lake and Houwu fish-farm, the quality status of these sediments was evaluated by adopting comprehensive pollution index and Hakanson ecological risk index. The sediments of the Taohuayuan River are most seriously polluted, reaching a moderate level of pollution(P=2.70,RI=171.02). Although the concentrations of Zn in the sediments of the Houliu River are high,the ecological risk is slight. The sediments of the other rivers have low pollution levels. The potential ecological risks follow the order of Taohuayuan River Houliu River Yangchang River Maxian River. Overall potential ecological risk is mainly attributed to Cd,whose potential ecological risks in all the sediments were identified to be moderate or severe,and the others only caused slight ecological risks. Aanalysis of the variations of the contents of the 8 heavy metals and TOC,Mo and Rb along with the depth profile shows that the deposition of Cd, Pb, Ni, Co, Cr, Cu, and V is controlled mainly by the variation of TOC during early diagenetic processes. Cr was determined in terms of redox conditions and diagenetic processes,and Zn was mainly governed by particle or grain size.