【作者】 孙雅辉；

【导师】 张银龙；

【作者基本信息】 南京林业大学 ， 水土保持与荒漠化防治， 2010， 硕士

【摘要】 本文以太湖百渎港河口湿地为研究对象,对沉积物进行了系统采样分析,测定了沉积物中Cd、Cr、Cu、Ni、Pb、Zn六种重金属含量,运用地统计学对数据的分析拟合功能和GIS的空间分析功能,进行了重金属含量的空间变异分析,在此基础上,综合采用污染负荷指数法和潜在污染生态指数法,对百渎港沉积物重金属进行污染评价。分析结果表明:(1)Cd、Cu、Ni和Zn,全部超过了背景值,Cr、Pb的大部分超过背景值。说明随着上游河流两岸城市化、工业化速度的加快,湿地沉积物中重金属含量随之呈明显富集的趋势。(2)Ni元素表现出较弱的空间相关性,说明受污染排放、湿地植物种类、管理水平等人为随机因素的影响较大。Cd、Pb、Zn这三种重金属元素含量的空间分布具有中等程度的空间相关性,随机效应与结构效应相接近。Cr、Cu两个元素表现出强烈的空间相关性,说明母质、地形、气候等结构性因素对其空间变异起着优势的主导作用。(3)在六种沉积物重金属中,Cu元素和Cd元素的污染最为严重,对百渎港重金属污染负荷的贡献最大,应作为优先控制污染物。重金属潜在生态风险从大到小的排序依次为:Cd>Cu>Ni>Pb>Zn>Cr。整体来看,潜在生态危害指数(RI)达到中度风险以上的样点,占总样点的81.25%,可见百渎港沉积物中重金属总体潜在生态危害已经呈现恶化趋势。更多还原

【Abstract】 In this study, heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were measured in the sediment of Baidu port estuary wetlands, Taihu lake. The methods of data fitting functions of geo-statistical analysis and spatial analysis function of GIS were used in the spatial variation analyses of heavy metals. On this basis, heavy metal pollution assessment in Baidu port estuary wetland was carried out by the methods of pollution load index and potential pollution ecological index. The results show that:(1)Cd, Cu, Ni and Zn contents were over the background value in all of the sampling points. And in most of them, Cr, Pb contents were the same. Help with the urbanization and industrialization accelerates on banks of upstream rivers, the trend that the heavy metals in sediment was accumulating was clear.(2)Ni content showed weak spatial correlation. It may be because that the element was affected by pollution, wetland plant species, management of human random factors such as larger. While, the content of the three heavy metals Cd, Pb, Zn showed moderate spatial correlation and similar random effects and structural effects. Cr, Cu showed strong spatial correlation- it showed that the description of parent material, topography, climate and other structural factors on the spatial variability play a dominant role.(3)In the six heavy metals in sediment, Cu and Cd created most serious pollution problem, and loaded the largest contribution to the heavy metal pollution. That made Cu and Cd be the priority pollutants. The order beginning with the largest potential ecological risks of heavy metals is that: Cd>Cu>Ni>Pb>Zn>Cr. Overall, there were 81.25% of total sample points, which the potential ecological risk index (RI) were beyond the moderate risk level. All above showed that heavy metals have been presented against total potential ecological deterioration.更多还原