【作者】 羊建波；

【导师】 赖健清； 李德胜；

【作者基本信息】 中南大学 ， 构造地质学， 2010， 硕士

【摘要】 本文在太原盆地多目标地球化学调查项目资料的总结和分析基础上,以汞、镉、铅、砷、铬、镍、铜、锌等8种重金属元素为主要研究对象,采用标准化方法,相对累积频率方法和含量-面积法确定了重金属元素的环境地球化学基线。采用地质累积指数法和污染程度评价法对该地区土壤环境质量做出评价,结合太原盆地的地质条件、地理条件和社会活动情况,讨论了重金属元素的自然来源和人为来源。首先分析研究区土壤重金属元素的含量分布特征,然后采用标准化方法,相对累积频率方法和含量-面积法分别确定了重金属元素的地球化学基线值。通过对三种方法的比较,本文以含量-面积法确定的基线值为土壤重金属元素污染评价的标准,基线值分别为As 13.02×10-6, Cd 0.18×10-6,Cr 86.67×10-6, Cu 35.68×10-6,Hg 0.22×10-6,Ni 38.07×10-6,Pb 30.25×10-6,Zn 88.46×10-6。基于确定的基线值,本文以污染程度指数作为污染分析的标准,对表层土壤中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn元素进行了评价。各元素的污染程度指数大多<1,属无污染和轻度污染,有部分样点污染程度指数>1,为中度污染和强污染。研究区表层土壤各元素污染级别的大小顺序为Hg>Cd>Zn>Pb>Cu>Cr>As>Ni。研究表明,研究区污染最为严重的重金属元素为Hg和Cd,其次为Zn、Pb、Cu、Cr等；受到综合污染最为严重的区域为太原市区、汾阳-孝义区及其附近。结合太原盆地的土壤重金属污染分析结果和太原盆地地质、工农业等情况,初步讨论重金属元素的来源。Cd、Hg、Cu、Ni和Zn元素的自然来源主要为边山地层,如靠近周边石炭系和二叠系,但自然来源对土壤中重金属高含量的影响很小,主要的还是人为的影响。Cr、As、Pb的高含量与边山地层无关,局部的元素富集最主要是人类活动影响的结果。更多还原

【Abstract】 On the basis of summarizing and analyzing geochemical data from the project of Multi-purpose Geochemical Survey of Taiyuan Basin, the geochemical baseline of 8 heavy-metal elements Cd, Cr, Hg, Ni, Pb, Zn, As and Cu in the soil of the Taiyuan Basin were researched using standardized method, relative cumulative frequency method, and content-area method (C-A).Accordingly, the Geoaccumulation Index and Contamination Degree Index were adopted for assessing heavy metal pollution degree,and the sources of heavy metals were discussed.First of all, the spatial distribution characters of heavy metals were studied in detail, and the geochemical baselines were calculated by means of standardized method, relative cumulative-frequency method and C-A method. Determined by statistics of C-A method contrasting to other methods, the geochemical baselines of As, Cd, Cr, Cu,Hg, Ni, Pb, and Zn, which were regarded as the evaluating criteria of the heavy metal pollution degree, are 13.02×10-6,0.18×10-6,86.67×10-6,35.68×10-6,0.22×10-6, 38.07×10-6,30.25×10-6, and 88.46×10-6, respectively.Secondly, the pollution status of 8 heavy-metal elements were analyzed using Pollution Degree Index. Most of the surficial soil in Taiyuan Basin suffer no or slight pollution, and the pollution degree index of each element is smaller than 1,other than part over 1,suffering mid-pollution or strong pollution. According to the size of pollution degree index, the order of pollution degree is as follows:Hg> Cd> Zn> Pb> Cu> Cr> As> Ni.The study shows that the most polluted heavy metal elements are Hg and Cd, followed by Zn, Pb, Cu, Cr, etc. The most comprehensive polluted areas are Taiyuan, Fenyang-Xiaoyi zone and its vicinity.Finally, the sources of heavy metals were discussed by associating pollution status, geology and industrial and agricultural situation of the Taiyuan Basin. The natural source of Cd、Hg、Cu、Ni and Zn is mainly the strata in the mountains around the basin,usually Carboniferous System and Permian System. This kind of source has little impact on high contents of soil heavy metals,but the main factor is anthropogenic source. High contents of elements Cr、As、Pb are not related to the strata near the basin, and locally caused by human activities.更多还原