为顺利开展城市河道污染整治工程,有效控制河道底泥引发的二次污染,研究河道底泥污染特征并分析其生态风险具有重要意义。基于台州安溶泾河道底泥检测结果,采用单项污染指数法、潜在生态风险指数法、聚类分析法等多种方法对底泥重金属含量、污染状况、空间分布、生态风险等进行评价。结果表明:底泥中Cu、Zn、Pb、Cd这4种重金属污染严重;从流域上看,主要污染区域为安溶泾上游段、2条支流段和支流与干流交汇处;从河道纵剖面上看,随着底泥深度的增加,超标重金属浓度普遍降低;Cu和Cd的潜在生态危害较严重,且在安溶泾上游段源头、2条支流及支流与干流交汇处底泥Cd和Cu的受污染程度最为严重。研究成果可为城市河道底泥重金属污染的预防和综合整治提供依据。

Researching the characteristics of river sediment contamination and analyzing its ecological risks are of crucial importance to river regulation projects and to the controlling of secondary pollution. With the sediments detection results of Anrongjing River in Taizhou as a case study, we evaluated the heavy metal concentration, pollution state, spatial distribution, and ecological risks by analyzing single pollution index, potential ecological risk index, as well as cluster analysis. Results revealed that the sediments in Anrongjing River were severely contaminated with Cu, Zn, Pb, and Cd. In plane scale, pollution mainly concentrated in the upstream, the two tributaries, and the junction between tributaries and mainstream; in longitudinal sectional scale, the concentration of heavy metals declined with the deepening of sediments. Cu and Cd posed severe potential ecological risks, and also the pollution of Cd and Cu in the source, the two tributaries and the junction between tributaries and mainstream were the most serious.