长江口及邻近海域沉积物重金属分布特征及生态风险评价

调查了2009年长江口及其邻近海域表层沉积物中Cu、Pb、Zn、Cd、Cr、Hg、As的含量,平均含量为Cu 27.88 mg/kg、Pb 22.98 mg/kg、Zn 95.88 mg/kg、Cd 0.178 mg/kg、Cr 41.01 mg/kg、Hg 0.031 mg/kg、As 11.40 mg/kg。空间分布上,Cu、Pb、Zn、Cd、Hg、As 6种重金属含量均在杭州湾北部及长江口南汇交界处呈现最大值,而Cr在调查海域的东部逐渐向近岸海域递减。运用主成分分析评价沉积物中重金属污染来源,同时采用Hakanson指数法评价了沉积物重金属生态风险,结果显示：长江口及其邻近海域表层沉积物中重金属元素的潜在生态风险整体表现为轻微。7种重金属元素对长江口及邻近海域潜在生态综合危害的大小贡献顺序为：Cd〉As〉Hg〉Cu=Pb〉Cr〉Zn。Cd的Eir值对RI值的权重贡献最大,即Cd表现为首要的潜在生态风险因子。

Distribution Patterns of Heavy Metals in Sediments of the Yangtze Estuary and its Adjacent Areas and Ecological Risk Assessment

The contents of Cu,Pb,Zn,Cd,Cr,Hg,As in surface sediments of the Yangtze estuary and its adjacent areas were surveyed in 2009.The average contents of Cu,Pb,Zn,Cd,Cr,Hg,As were 27.88 mg/kg,22.98 mg/kg,95.88 mg/kg,0.178 mg/kg,41.01 mg/kg,0.031 mg/kg,11.40 mg/kg respectively.From the spatial distribution,heavy metal content such as Cu,Pb,Zn,Cd,Hg,As show the maximum at the crossing of the north of Hangzhou bay and the south of Yangtze estuary,but Cr diminishes from the east of searching waters to shore waters.Application of principal component analysis（PCA） for the source of heavy metal contamination in sediments of estimation,adopt Hakanson index method assessing ecological risk of heavy metal from sediments.The results showed that its potential ecological risk are in a state of light-pollution for elementary of heavy metals in surface sediments of the yangtze estuary and its adjacent areas.The order of potential ecological integrative damage is,CdAsHgCu=PbCrZn.Corresponding pollution degree and potential risk degree of Eir and RI,Proportion of Cd＇s Eir value in highest contribution to value of RI.Cd was the worst of the potential ecological risk genes.