北京北部水源地沉积物中重金属元素分布及形态研究

Analysis on Distribution and Partition of Heavy Metal in Sediments of Northern Beijing Water Source

研究了北京北部以密云水库为中心的水系沉积物中砷、镉、铬、铅、铜和锌的分布特征和形态特征。结果表明,采样区域内砷、镉、铬及锌含量均高于北京土壤背景值,且在靠近市区的几个采样点各重金属浓度偏高尤为明显。采用连续提取法处理样品,评价了各种金属的生态有效性,结果显示6种重金属元素生态风险由强至弱的顺序为:镉>铜>铅>锌>铬>砷。镉为中高污染水平,对水体环境的污染突出。该研究数据将为北京市环境污染防治及城市规划提供帮助。

The characteristics of distributions and partitions of heavy metals（As ,Cd ,Cr ,Pb,Cu and Zn）in river sediments of north of Beijing were studied to determine the environmental pollution level. Compared to background values of Beijing,the heavy metals in the study area were higher, and in some sampling points which closed to the city,the heavy metals contents were higher than others. The speciation of heavy metals （As,Cd,Cr and Zn）in sediments from sampling sites were analyzed using a sequential extraction procedure. On the basis of experimental data ,six heavy metals were assessed,and the ecological risk in the descending order was Cd,Cu,Pb,Zn,Cr,As. The risk assessment of Cd was between medium risk and high risk,which may cause deleterious effects to aquatic environment. The present data will help in formulating guidelines for environmental pollution control and city planning in Beijing.