银川阅海湿地沉积物重金属潜在生态危害评价

为确定银川市阅海湿地湖水底泥中重金属的污染状态及潜在的生态危险，笔者采集了该湿地底泥，分析了8种常见重金属(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn)的含量及富集情况，又以现代工业化前正常颗粒底泥中重金属含量的最高背景值和自然背景值为参比值，对湿地底泥重金属的富集系数、生态危害系数及各采样点的生态危害指数进行探讨，最后运用Lars Hankanson潜在生态危害指数法对湿地底泥中重金属的生态危害程度做了评价。结果表明：以现代工业化前正常颗粒底泥中重金属含量的最高背景值为参比值，阅海湿地重金属富集顺序为Cr＞Pb＞Zn＞Cu＞As＞Cd＞Hg；各重金属单因子生态危害程度为Cd＞As＞Hg＞Pb＞Cu＞Cr＞Zn，其中4号采样点的重金属潜在生态危害程度较高，其他采样点生态危害程度较轻微。总而言之，银川市阅海湿地底泥重金属的生态危害程度还是较小的。

Potential Ecological Risk Assessment of Heavy Metals in Superficial Sediments of Yuehai Wetland

In order to investigate heavy metal pollution and its potential ecological risk in sediments of Yuehai wetland, content and accumulation of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) were investigated. The highest values for heavy metals concentrations in sediments before the modern industrialization of the world and the natural background values were used to analyze the accumulation coefficient and potential ecological risk (PER) coefficients for heavy metal. The PER index for each sample location was also discussed. The method for evaluating PER index presented by Lars Hankanson was applied to assess the ecological risk. The results showed that when the highest values for heavy metals concentrations in sediments before the modern industrialization of the world were taken as references, the accumulation order for those heavy metals was Cr>Pb>Zn>Cu>As>Cd>Hg, the potential risk order of elements was Cd>As>Hg>Pb>Cu>Cr>Zn. The 4th sample point was under the highest potential risk,, which is much higher than other elements, the while the others had relatively small risk. To sum up, the potential ecological risk of Yuehai wetland was light, at least not very serious.