太湖沿岸湖区底泥重金属污染分布特征及生态风险评价OACSTPCD

To further explore the pollution status and environmental treatment measures of the sediments in Taihu Lake,this study monitored the contents of eight heavy metals in the sediments of 229 sampling points in different bays of Taihu Lake,analyzed their distribution characteristics,sources and ecological risks.The results showed that the average content of Zn,Cr,Ni,Cu,Pb,As,Cd,Hg in the surface sediments of Taihu Lake was(126.86±73.31),(90.25±47.66),(44.62±24.30),(39.36±28.46),(36.86±7.84),(11.65±5.33),(0.86±1.31),(0.08±0.04)mg/kg,except for Hg were higher than its background value.The geo-accumulation index indicated that the Hg,As,Cr,and Cd were generally non-polluted,the Cu,Zn,Pb and Ni amount to a low pollution state.The results of potential ecological risk index showed that,except for the northwestern coastal area had a strong potential ecological risk and the Zhushan Lake had a medium ecological risk in the depth of 0～30 cm,the other lake bays had a low potential ecological risk within the depth of 0～100 cm.Correlation analysis and PCA analysis showed that Zn,Cu,Ni,Cr,Hg and Pb had strong homology,and they were the first major component of pollutants,mostly from industrial pollution sources.Cd was the second major pollutant,which had little homology with other components and was related to agricultural pollution sources.Compared to 2003,the average Cr and Cu contents in the surface sediment of coastal lake areas has increased,while the contents of Hg and Pb has decreased.