论文部分内容阅读
对广西某铅锌矿区周边农田表层进行了采样分析,测定了土壤中Zn、Pb、Cd、Hg、Cu、As、Ni、Cr的含量,依据土壤环境质量标准,分析了研究区域内表层土壤重金属污染程度,并通过主要成分分析和半变异函数分析,对重金属的空间分布特征进行了研究。结果表明,调查区域不同程度地受到Zn、Pb、Cd、Hg、Cu、As、Ni、Cr的污染。其中污染最重的是Cd,1 00%超标,超标倍数在0.67～311.93之间;其次是Zn、Hg、Pb,超标率分别为97%、84%、36%,平均超标倍数分别为10.94、3.03、1.09;污染较轻的是As、Ni、Cu、Cr。主成分分析结果将8种重金属元素分为第一主成分(Zn、Pb、Cd、Hg)和第二主成分(As、Ni、Cu、Cr),第一和第二主成分的贡献率分别为54.36%和31.1 9%。第一主成分在离矿区较近的西北偏西面有着较高的分布,说明第一主成分主要受铅锌矿厂污染的影响;而第二主成分在离矿区较近的西北偏西面和离矿区较远的东南偏南面都有着较高的分布,说明第二主成分不仅与铅锌矿厂的污染有关,而且与土壤母质也有很大的关系。
The surface layer of farmland around a Pb-Zn mining area in Guangxi was sampled and analyzed. The contents of Zn, Pb, Cd, Hg, Cu, As, Ni and Cr in the soil were determined. According to the soil environmental quality standard, The degree of pollution was analyzed. The spatial distribution characteristics of heavy metals were studied by principal component analysis and semi-variogram analysis. The results show that the survey area is polluted by Zn, Pb, Cd, Hg, Cu, As, Ni and Cr to some extent. Among them, Cd was the most polluted, exceeded the standard of 100%, the over standard multiple was between 0.67 and 311.93, followed by Zn, Hg and Pb, the over standard rates were 97%, 84% and 36% respectively. The average over standard multiples were 10.94, 3.03, 1.09; Asp, Ni, Cu, Cr are the less polluting ones. The results of principal component analysis divided the eight heavy metal elements into the first principal component (Zn, Pb, Cd, Hg) and the second principal component (As, Ni, Cu, Cr) 54.36% and 31.1 9% respectively. The first principal component has a higher distribution in the west-northwest near the ore-dressing area, indicating that the first principal component is mainly affected by lead-zinc mine pollution. The second principal component is located west-northwest near the ore-dressing area And southeastern and south-easterly areas far away from the mining area have higher distribution, indicating that the second principal component is not only related to lead-zinc mine pollution, but also has a great relationship with the soil parent material.