湖北鄂州城市湖泊底泥重金属空间分布特征与污染评价

以湖北省鄂州市某湖泊底泥重金属为研究对象,在调查和分析的基础上,采用地质累积指数和潜在生态危害指数对底泥中的重金属分布以及污染状况进行评价。结果表明:从柱状底泥纵向分布来看,该湖底泥重金属含量整体上呈现从上到下递减的变化趋势,上层底泥重金属含量最高;从空间分布上看,3个湖区重金属污染程度排序是西湖区域＞东湖区域＞中湖区域。地质累积指数评价结果显示该湖底泥重金属主要以无污染—中度污染为主,底泥中重金属污染程度的大小排序为Cd＞Zn＞Cu＞Pb＞Ni＞Cr＞Hg＞As;潜在生态危害指数法的评价结果显示底泥中As、Ni、Cu、Pb、Cr和Zn生态风险水平较低,Cd和Hg存在着不同程度的潜在生态风险,Cd的潜在生态风险最高。研究成果为该湖泊的污染调查和评价分析提供参考,并为湖泊后续的保护和水环境系统的可持续发展提供科学依据。

Spatial Distribution and Pollution Evaluation of Heavy Metals in a Lake Sediment in Ezhou City of Hubei Province

On the basis of investigation and analysis of heavy metals in the sediment of an urban lake in Ezhou, Hubei Province, the heavy metals in the sediment were evaluated according to geologic accumulation index and potential ecological hazard index. Results indicated that heavy metal concentration in the sediment declined from top to bottom, and the heavy metal content in the upper sediment was the highest. The west region of lake subjected to the most severe pollution of heavy metals, followed by the east region and the middle region in sequence. In terms of geological accumulation index, heavy metals in the sediment were mainly pollution-free to moderately polluted; the pollution degree of different heavy metals followed the order of Cd>Zn>Cu>Pb>Ni>Cr>Hg>As. According to the potential ecological risk index, As, Ni, Cu, Pb, Cr and Zn in the sediment posed low ecological risk, whereas Cd and Hg had potential ecological risk at different degrees, and Cd posed the highest ecological risk.