城市湖泊表层沉积物中的重金属污染现状及其风险评价——以武汉墨水湖为例

水体沉积物中的重金属会对生态系统构成直接和间接的威胁.为了研究工业化、城市化过程中城市湖泊沉积物重金属污染现状及其暴露风险，以武汉市墨水湖为研究对象，测定了5种重金属Zn、Cu、Ni、Pb及Cr在表层沉积物中的含量，分析了其污染程度、分布特征，并对其稳定度进行了分析.结果表明，墨水湖表层沉积物重金属污染程度较重，在所有采样点5种重金属含量均高于最低效应阈值（LEL），多数采样点甚至超过了严重效应阈值（SEL）.该湖泊沉积物中重金属分布具有比较明显的空间差异性：排污口区>湖中心水域>城区岸边带>林田岸边带；其稳定程度依次为：Zn < Cu < Ni < Pb < Cr，其中Zn交换态及碳酸盐结合态比例超过50%，稳定程度极低.而Pb、Cr稳定程度较高，其交换态及碳酸盐结合态比例小于10%.像墨水湖这样受纳高污染负荷市政污水、暴雨径流的城市湖泊，其潜在的重金属生物活性，必须引起足够的重视.

Heavy Metals Pollution Status and Its Stability Assessment in Surface Sediments of Urban Lake-- A Case Study of Moshui Lake in Wuhan

Trace heavy metals can cause direct or indirect damages to aquatic ecosystem and human health. To evaluate the heavy metal pollution status of urban lakes, the concentrations and distribution of five trace metals Cr, Cu, Ni, Pb and Zn were detected in the surface sediments of Moshui Lake located in Wuhan City, and the pollution extent and stability were analysed. High pollution extent of heavy metal was found for the surface sediments in this urban lake. All these 5 trace metals'contents exceeded the least effect level(LEL)at all the sampling sites, with most of them exceeding the severe effect level(SEL). A distinct spatial heterogeneity was found in these heavy metals distribution, and the Stability Assessment Code(SAC)was in the order of Zn