【作者】 祁轶宏；

【导师】 袁峰；

【作者基本信息】 合肥工业大学 ， 矿物学、岩石学、矿床学， 2006， 硕士

【摘要】 重金属元素污染是破坏土壤环境的重要因素,并直接或间接危害到人体健康。安徽铜陵作为我国主要的矿业城市,环境污染较为严重。铜、金等多金属矿床的开发和冶炼,已成为铜陵地区土壤环境重金属污染的重要污染源。 本文围绕重金属污染较为严重的铜陵地区,开展了基于GIS的土壤重金属元素的空间分布及污染评价研究。首先基于Hazen概率曲线计算了铜陵地区土壤重金属元素的背景含量,计算结果与实际情况基本一致,各项参数的成因意义明确,符合客观实际。 采用地累积指数法、潜在生态危害指数法、沉积物富集系数法、模糊集理论和污染负荷指数法对铜陵地区土壤重金属污染进行了相应的评价,确定了Cd、Pb、As是整个研究区主要的重金属污染元素;Zn、Cu、Mn等元素的污染主要集中在矿床附近;Hg和Tl在土壤中的含量虽不高但由于其很高的生物毒性也存在污染。 利用地质统计学工具结合MAPGIS软件进行了铜陵地区土壤重金属元素的空间分布特征研究,变异函数的计算结果很好的解释了重金属元素分布的空间结构性,GIS软件绘制的空间分布等值线图直观地反映出不同污染区域所处的位置及范围。对比含量分布等值线图和评价等值线图,得出对污染区域位置的反映基本上是一致的,但评价等值线图对污染区域的描述更加精细。 应用MAPGIS软件并结合数学模型直观的再现了铜陵地区土壤相对环境容量的空间分异特征,研究表明铜陵地区土壤的相对环境容量属于中等水平,环境地球化学质量一般,As、Pb元素的相对环境容量总体上稍高,而Cd元素的相对环境容量则非常低,造成铜陵地区土壤元素相对环境容量空间分异的原因主要是元素的自然背景分异,同时也存在人为因素的影响。 在铜陵地区土壤重金属元素空间分布特征研究的基础之上,进行了污染的影响因素分析,得出矿床是造成As、Cd、Pb、Zn四种元素污染的主要原因,而Hg元素污染则主要与排污企业、城镇有关,研究发现水系作为污染传播的一个载体是造成大面积连续污染的原因之一。本文还从影响因素分析结果的角度对不同评价方法的有效性进行了验证,得出了适用于不同重金属元素的评价方法。更多还原

【Abstract】 The heavy metal elements pollution is the important factor that breaks the soil environment and endanger to the human body health directly or indirectly. Tongling is the main mineral industry city in China, and the environmental pollution is very serious in Tongling. The exploitation and smelting of metals deposit such as copper, gold and so on, have become the important heavy metals pollution source of the soil in Tongling area.This paper studies the spatial distribution of heavy metal elements based on GIS in the soil of Tongling area where the heavy metal pollution is more serious, and assesses the pollution degree. First, the background content of heavy metal elements in soil are calculated based on Hazen probability curve in Tongling area. The calculations are consistent with the actual situation, the meaning of the causes of the parameters is clear and in line with the objective reality.The pollution degree of heavy metal elements in soil is assessed by Index of Geoaccumulation, Potential Ecological Risk Index, Sediment Enrichment Factor, Fuzzy theory and Pollution Load Index. Assessment identifies Cd, Pb, As are the primary heavy metal elements that cause the pollution. The pollution of Zn, Cu, Mn is close to the deposits. Hg and T1 content in the soil is not high, but the pollution is also existent because of its high biological toxicity.The spatial distribution characteristics of heavy metal elements in the soil of Tongling area are studied using geostatistics method and MAPGIS software. The calculations of variogram commendably explain the spatial structures of the heavy metal elements distribution. The location and scope of pollution area can be showed visually on isopleth map plotted by GIS software. Content distribution isopleth map and assessement isopleth map show that the location of pollution area is basically the same, but assessment isopleth map describes the pollution area more elaborately.The spatial characteristics of relative environmental capacity of the soil are reflected visually using MAPGIS software and a mathematical model. The research shows that the relative environmental capacity of the soil in Tongling area is at the middle level, the quality of environmental geochemistry general is common. The relative environmental capacity of As and Pb elements is high, but the relative environmental capacity of Cd elements is very low. The results show that the main cause of the spatial characteristics of relative environmental capacity of elements is the natural separation of elements, moreoverthe impact of human factors is exist.The factors of pollution impact are analysed based on the study of the spatial distribution characteristics of heavy metal elements in the soil of Tongling area. The pollution of As, Cd, Pb, Zn elements is mainly caused by deposits, and the pollution of Hg is mainly caused by enterprises and towns. The study indicates that water as a large carrier of pollution is one of the reasons for large-scale pollution. In addition, the efficiency of different methods of assessment is validated based on the factor analysis of pollution impact. The applicability of assessment methods to different elements has been found.更多还原