中文摘要：

利用等离子质谱仪（ICP-MS）测定了长江口及其邻近海域表层沉积物细颗粒组分（〈63μm）的重金属，平均含量为As10.47 mg·kg^-1、Cd 0.19 mg·kg^-1、Cu 37.68 mg·kg^-1、Pb 36.86 mg·kg^-1、Cr 97.80 mg·kg^-1、Zn 98.65 mg·kg^-1.空间分布上，As、Cd和Cu含量随着离岸距离的增大有递减的趋势，Pb、Cr和Zn含量变化不显著，调查海区南部海域的重金属含量普遍比北部海域高.单因子污染评价显示，调查海域底质局部已经受到了As、Cu、Pb、Cr和Zn的中度污染，而Cd的影响较轻微.依据沉积物质量基准（SQGs）对本区沉积物环境质量评价表明，大部分站位As、Cu和Cr 3种重金属的含量位于效应浓度低值（ERL）和效应浓度中值（ERM）之间，只是偶尔产生不利的生物效应;Cd、Pb、Zn 3种重金属的含量都低于ERL或大部分站位低于ERL，几乎不会产生不利的生物效应.对底质综合环境质量进行的因子分析和系统聚类分析结果显示，长江口外和杭州湾外近海海域的综合底质环境较差，应引起重视。

英文摘要：

The concentrations of six heavy metals were determined in the fine fraction （ 〈 63 μm） of surface sediments in the Yangtze Estuary and its adjacent areas by an inductively coupled plasma mass spectroscopy （ICP-MS）. The average contents of As, Cd, Cu, Pb, Cr and Zn are 10.47,0.19,37.68,36.86, 97.80 and 98.65 mg·kg^-1 , respectively. The contents of As, Cd and Cu appear gradually degressive from west to east, while the contents of Pb, Cr and Zn appear no apparent difference. In generally, the concentrations of heavy metals are higher in the south sea areas than those in the north sea areas. Environmental assessment with single factor method suggests that As,Cu, Pb,Cr and Zn are moderately contaminated, while Cd is not polluted. The values of As,Cu and Cr are between effect range-low （ERL） and effect range-median （ ERM）, which indicate they occasionally bring adverse biological effect at most stations, and the values of Cd, Pb and Zn are below ERL mean they rarely bring adverse biological effect by sediment quality guidelines assessment. From the results of factor analysis and cluster analysis, we conclude that the outer sea areas of the Yangtze Estuary and the Hangzhou Bay have lower sediment environmental quality, therefore much attention should be paid to these areas.