仙山湖湿地土壤重金属空间分布特征与生态风险评价

摘要

2014年4月,在浙江省长兴县仙山湖周边设置了15个采样点,共采集了45个土壤样品,分析Cu,Zn,Cr,Pb,Cd,As及Hg的含量水平及其分布特征,采用地累积指数、潜在生态危害指数法,对仙山湖土壤重金属污染进行评价.结果表明,在仙山湖周边各层土壤中,大部分所测元素含量低于国家土壤环境一级标准,部分样点Hg,Zn和Cd含量超标.在不同土地利用类型中,公路沿线的Cu及Cd含量较高;湖区下游土壤的Cu,Pb,Hg含量较高,Cd含量较低;湿地边滩、苗圃的土壤重金属含量变化不明显.在土壤垂直分布中,多数所测元素无明显变化规律.地累积指数表明,7种元素污染程度均属于无污染;潜在生态风险指数表明,部分样地的Hg潜在生态风险等级为中等及较强级别,应引起重视.%Determinations on content of 7 element, namely Cu, Zn, Cr, Pb, Cd, As and Hg were implemented in the soils from different layers in 15 sampling points around Xianshanhu Wetland of Changxing, Zhejiang province in April, 2014. Contamination of above-mentioned elements was assessed by index of geoaccumulation and potential ecological risk index. The result demonstrated that contents of most tested elements at different layers in the soil around Xianshanhu were lower than national soil environmental standards, only Hg, Zn and Cd content was over-limit at some of the points. The content of Cu and Cd was higher in the soil of roadside, the content of Cu, Pb and Hg was higher in the downstream of the lake, while the content of Cd was lower. The content of tested elements had no obvious variation in the nursery and the marginal bank of the wetland. Most of tested elements had no obvious regularity in the vertical distribution of soil. Index of geoaccumulation showed that the soil was not polluted by these elements. Potential ecological risk index showed that Hg had medium to high risk index at some points, which was need to be paid attention.