临涣矿区土壤重金属元素含量和迁移特征研究

发布时间：2018-02-25 22:19

本文关键词： 临涣矿区土壤玉米植株重金属含量特征迁移规律　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,随着煤矿工业的快速发展,土壤中重金属含量不断增加。作为不可降解污染物,重金属不仅可以降低水体、大气和农作物的质量,而且通过食物链富集,对人体健康和生存产生危害。因此,矿区土壤重金属污染问题一直备受国内外专家和学者的关注。为探索矿区土壤重金属元素含量与迁移特征,以淮北煤田的临涣矿区为研究对象,共采集39个表层土样、24个深层土样和相应的35个玉米植株样品,并测试了七种重金属(Mn、Cd、Ni、Pb、Cr、Zn和Cu)的总量和五种形态含量。本研究对土壤重金属污染程度和生态风险进行评价,利用多元统计和地统计法分别对重金属污染来源和空间分布特征进行解析,并对重金属在土壤中的水平和垂向迁移规律,以及在土壤-玉米植株体系中的迁移规律进行研究。主要结论如下:(1)矿区七种重金属除Cd略有超标外,其余均未超过国家土壤环境质量二级标准,Cr的污染最小;根据土壤重金属评价结果,Cd的污染程度和生态危害水平较大,其余元素都属于清洁和轻度生态危害水平,且综合污染评价指数稍高的区域主要集中在任楼矿、海孜矿和童亭矿;多元统计分析表明,Mn、Cd、Ni、Cr主要受煤矿开采等工业和农业活动等人为污染,以及自然因素的混合影响,Cu、Zn和Pb则主要来源于交通运输;根据空间分布特征,除Cd外,其余几种重金属的含量均呈现西北部高于东南部,浓度较高处主要集中于采煤时间较长的研究区北部地区。(2)矿区土壤各重金属的形态都以残渣态含量最高,潜在迁移性大小为NiCdPbMnCuZnCr;矸石附近土壤中以Mn、Cd、Pb和Zn含量较高,随着距矸石山的距离增大各重金属含量基本呈减少趋势,土壤重金属垂向迁移难易程度为NiCu、ZnCr、Cd、MnPb,其中Mn和Ni分别在土壤水平和垂直方向上具有一定迁移性。(3)玉米植株除叶部中少量Mn和Cu来源于大气飘尘外,茎和叶部中其它重金属主要来源于根从土壤的吸收,且根部重金属含量最高;玉米植株中Cd的富集系数和Mn的转移系数最大,各部位对Mn和Cd的吸收不受土壤形态的影响。
[Abstract]:In recent years, with the rapid development of coal industry, the content of heavy metals in soil is increasing. As non-degradable pollutants, heavy metals can not only reduce the quality of water, atmosphere and crops, but also enrich through the food chain. Therefore, the pollution of soil heavy metals in mining areas has been concerned by experts and scholars at home and abroad. In order to explore the content and migration characteristics of heavy metals in the soil of mining areas, A total of 39 surface soil samples, 24 deep soil samples and 35 maize plant samples were collected from Linhuan mining area in Huaibei coal field. The total amount and five forms of Zn and Cu in seven heavy metals (Mn-CdCU) were measured. The pollution degree and ecological risk of heavy metals in soil were evaluated in this study. The sources and spatial distribution characteristics of heavy metal pollution were analyzed by multivariate statistics and geostatistics, and the horizontal and vertical transport patterns of heavy metals in soil were analyzed. The main conclusions are as follows: (1) the pollution of seven heavy metals in the mining area, except that CD is slightly over the standard, does not exceed the national secondary standard for soil environmental quality. According to the results of soil heavy metal evaluation, the pollution degree and ecological hazard level of CD were relatively large, and the other elements belonged to clean and light ecological hazard level, and the areas with higher comprehensive pollution assessment index were mainly concentrated in Renlou Mine, Haizi Mine and Tongting Mine. The results of multivariate statistical analysis show that the Cr is mainly polluted by industrial and agricultural activities such as coal mining, and the mixed influence of natural factors mainly comes from transportation, except CD, according to the spatial distribution characteristics. The contents of the other heavy metals were higher in the northwest than in the southeast, and the concentrations were mainly concentrated in the northern area of the study area where the mining time was longer. The forms of heavy metals in the soil of the mining area were all the highest in the residual state, and the content of the heavy metals in the soil was the highest in the mining area. The potential mobility was NiCdPbMnCuZnCr.The contents of Pb and Zn in soil near gangue were higher, and the contents of heavy metals decreased with the increase of distance from gangue mountain. The vertical migration of heavy metals in the soil was difficult and easy. Among them, mn and Ni had a certain migration in the horizontal and vertical direction of soil, respectively.) A small amount of mn and Cu in the leaves of maize plants were derived from atmospheric dust, respectively. Other heavy metals in stems and leaves were mainly derived from the root absorption from soil, and the highest content of heavy metals was found in the roots, while the CD enrichment coefficient and mn transfer coefficient in maize plants were the largest, and the uptake of mn and CD by different parts was not affected by soil morphology.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

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