GEOCHEMICAL CHARACTERISTICS AND RISK ASSESSMENT OF HEAVY METALS IN SEDIMENTS FROM HONGFENG LAKE

Eight heavy metals(Cd,Pb,As,Hg,Cu,Zn,Fe and Mn) in 13 surface sediment samples collected from Hongfeng Lake in the karstic area of Guizhou Province,were analyzed to study contamination characteristics of heavy metals,and the potential ecological risk index(RI) method was employed to assess the potential risk induced by these heavy metals.The results obtained in this study indicate that the concentrations of these heavy metals follow the order: Fe Mn Zn Cu As Pb Cd Hg.Levels of the heavy metals in the north part of the lake were generally higher than those in the south part.Statistical analysis suggests correlations among Al,K,Ca,Na,P and the eight heavy metals,demonstrating the complex factors affecting the distribution characteristics of heavy metals in sediments.Ca showed significant negative correlation with most of the heavy metals,while the rest of the elements had positive correlations with the heavy metals.According to the ecological risk assessment,Hongfeng Lake might face a regional water pollution,and the ecological risk caused by the heavy metals in the north part of the lake was generally higher than that in the south part.Cd and Hg were the major contributors to potential ecological risk index among these heavy metals,and exerted a direct influence of ecological risk on the lake.