填埋场周边土壤的重金属污染特性研究及评价

发布时间：2018-10-24 21:25

【摘要】：本论文以某填埋场周边土壤为研究对象,通过设置采样点对土壤进行采集,将采集回来的土壤在实验室内进行重金属含量的测定,并在测得结果统计的基础上应用多种不同的评价方法对土壤的污染程度进行评价,最终得出如下结论：(1)所选区域土壤性质为偏碱性土壤,土壤的pH值平均为7.94。土壤中的铜、铅、锌离子含量较高,存在超标现象,说明上述三种重金属在土壤中有一定的累积。土壤中铬离子的含量较低,接近背景值水平,无重金属累积现象的发生。(2)水平方向上,重金属离子的含量与距离的关系较为明显,即距离填埋场越远,含量越低。垂直方向上,不同深度的土壤中重金属含量也不同,整体呈现出取样深含量少的规律；根据Cu、Pb、Zn、Cr之间相关系数的计算结果,前三者存在明显的正相关性,推测上述三种重金属的同时超标是由填埋场的存在引起的；Cr与其他三种重金属之间相关性不大,并且Cr含量也没有超标情况,说明填埋场周边的土壤没有被Cr污染。(3)通过单因子污染指数结果发现：30个取样点中,受到Cu轻度污染的样点数为2个,单因子污染指数的最大值为1.56；受到Pb轻度污染的样点为3个,最大Pb污染指数为1.46。受到Zn轻度污染的样点数为3个,中度污染的样点数为3个,最大Zn污染指数为2.52。(4)通过内梅罗综合污染指数法可知：距离填埋场100m范围内的土壤为轻度污染,100-500m范围内为污染警戒区,500m以外土壤未受到重金属污染。对土壤重金属污染贡献最大的是重金属Zn,没有出现重金属Cr的污染。(5)通过地累积指数法可知,研究区域土壤中重金属元素的污染级别排序为ZnCuPb Cr。根据采样点重金属地累积指数的平均值可以看出：30个采样点的重金属污染程度均未达到中度污染。(6)通过模糊数学法可知：填埋场周边土壤中存在重金属污染情况,污染等级在2级到3级之间,污染程度较轻。
[Abstract]:In this paper, the soil around a landfill is taken as the research object, and the heavy metal content of the collected soil is measured in the laboratory by setting up a sampling point to collect the soil. On the basis of the statistics of the measured results, a variety of different evaluation methods were used to evaluate the pollution degree of the soil. Finally, the following conclusions were drawn: (1) the soil properties of the selected region were alkaline, and the average pH value of the soil was 7.94. The content of Cu, Pb and Zn in soil is high, which indicates that the above three heavy metals are accumulated in soil to some extent. The content of chromium ion in soil is lower, which is close to the background value, and there is no accumulation of heavy metals. (2) in the horizontal direction, the relationship between the content of heavy metal ion and the distance is obvious, that is, the farther away from the landfill, the lower the content. In the vertical direction, the contents of heavy metals in the soils of different depths are also different, showing the law of less sampling depth as a whole, according to the calculation results of correlation coefficient between Cu,Pb,Zn,Cr, the former three have obvious positive correlation. It is assumed that the excess of these three heavy metals at the same time is caused by the presence of landfills, that there is little correlation between Cr and the other three heavy metals, and that the content of Cr does not exceed the standard. The results showed that the soil around the landfill was not polluted by Cr. (3) the results of single factor pollution index showed that: among the 30 sampling points, 2 samples were slightly polluted by Cu, and the maximum value of single factor pollution index was 1.56; Three samples were slightly polluted by Pb, and the maximum Pb pollution index was 1.46. There were 3 samples with mild Zn pollution and 3 with moderate pollution. The maximum Zn pollution index was 2.52. (4) through the comprehensive pollution index method of Nemero, the soil within 100 m from the landfill was slightly polluted, and the range from 100 to 500 m was the pollution warning area, and the soil beyond 500m was not contaminated by heavy metals. The biggest contribution to soil heavy metal pollution is that heavy metal Zn, does not occur heavy metal Cr pollution. (5) through the method of ground accumulation index, the pollution grade of heavy metal elements in the studied area is ranked as ZnCuPb Cr.. According to the average value of heavy metal accumulation index in sampling sites, it can be seen that the heavy metal pollution degree of 30 sampling sites is not up to moderate pollution. (6) through fuzzy mathematics method, we can know that heavy metal pollution exists in the soil around landfill site. The pollution level is between level 2 and level 3, and the pollution level is lighter.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X825

【参考文献】