南京城市林业土壤多环芳烃含量及分布研究

发布时间：2018-02-04 09:25

本文关键词： 城市林业土壤多环芳烃黑碳有机碳吸附　出处：《南京林业大学》2015年硕士论文　论文类型：学位论文

【摘要】：多环芳烃是一种在环境中广泛存在的持久性疏水有机污染物,由两个以上苯环以稠环形式相连,具有致癌、致畸变和致突变性。本文采用功能区采样的方法,以南京市城市林业不同土地利用方式区域中土壤作为研究对象,通过分析土壤中多环芳烃的含量、分布和来源来了解南京城市林业土壤中多环芳烃的分布规律及污染现状;并通过分析常见土壤理化性质与多环芳烃含量的相关性来了解多环芳烃在土壤中分布的影响因素;探究多环芳烃在城市林业土壤中的吸附行为并探究其在土壤中吸附行为的影响因素。主要研究结果如下:(1)城市林业不同功能区土壤中多环芳烃含量差异很大,变化范围是221.53~1134.90ug/kg,整个南京市城市林业表层土壤中多环芳烃的平均值为504.19ug/kg,不同功能区之间多环芳烃含量高低满足城市立交桥和道路绿化带土壤中多环芳烃的最高,居民区、学校和发电厂其次,垃圾填埋场、近郊森林和远郊森林最少;不同土壤层次之间多环芳烃含量满足表层高于中层高于下层的规律。通过分析表明道路绿化带,城市立交桥,发电厂,学校土壤中多环芳烃来源属于燃烧源,垃圾填埋厂,居民区,近郊森林,远郊森林土壤多环芳烃属于油类污染源。(2)南京城市林业土壤中有机碳与黑碳含量之间呈极显著正相关关系,Pearson相关系数为0.876;南京城市林业土壤中有机碳、黑碳均与多环芳烃含量呈极显著正相关关系,Pearson相关系数分别为0.611和0.789,黑碳对土壤中多环芳烃分布的影响大于有机碳对其影响。多环芳烃与速效钾的Pearson相关系数为0.319,呈显著正相关;与全氮的Pearson相关系数为0.673,呈极显著正相关。土壤粘粒百分比与多环芳烃的Pearson相关系数为0.654,呈极显著正相关。(3)南京市城市林业土壤对多环芳烃菲的吸附可以用Linear线性分配模型和Freundlich模型进行拟合,城市林业不同功能区中土壤对多环芳烃菲的吸附强度规律为:城市立交桥道路绿化带远郊森林近郊森林,不同土壤层次之间吸附强度为表层中层下层。含水率及pH值的增加会使土壤对菲的吸附能力有降低的趋势,有机碳含量及黑碳含量与吸附分配系数Kd均呈极显著正相关,相关系数为0.837和0.875;土壤粘粒百分比与Kd的Pearson相关系数为0.827,呈显著正相关。
[Abstract]:Polycyclic aromatic hydrocarbons (PAHs) are persistent hydrophobic organic pollutants widely existing in the environment. They are connected by two or more benzene rings in the form of dense rings, and have carcinogenic, teratogenic and mutagenic properties. The contents of polycyclic aromatic hydrocarbons (PAHs) in different land use areas of urban forestry in Nanjing were analyzed. Distribution and source of polycyclic aromatic hydrocarbons (PAHs) in urban forestry soils of Nanjing were studied. The influence factors of polycyclic aromatic hydrocarbons (PAHs) distribution in soil were analyzed by analyzing the correlation between physical and chemical properties of soil and PAHs content. To study the adsorption behavior of polycyclic aromatic hydrocarbons (PAHs) in urban forestry soils and the factors affecting their adsorption behavior. The main results are as follows: 1). The content of polycyclic aromatic hydrocarbons (PAHs) in soils of different functional areas of urban forestry is very different. The range of variation was 221.53 and 1134.90 ugr / kg, and the average value of PAHs in the topsoil of urban forestry in Nanjing was 504.19ugr / kg. The polycyclic aromatic hydrocarbons (PAHs) content in the soils of urban flyovers and road green belts was the highest, followed by residential areas, schools and power plants, landfill sites, forest in the suburbs and forests in the outer suburbs. The polycyclic aromatic hydrocarbons (PAHs) content in different soil layers is higher than that in the middle layer. The analysis shows that the sources of PAHs in the road green belt, urban flyovers, power plants and schools belong to combustion sources. MSW landfills, residential areas, forests in the suburbs, forest soils in the suburbs belong to oil pollution sources. 2) there is a very significant positive correlation between organic carbon and black carbon content in urban forestry soil in Nanjing. Pearson correlation coefficient was 0.876; The correlation coefficients of organic carbon, black carbon and polycyclic aromatic hydrocarbons (PAHs) were 0.611 and 0.789, respectively. The effect of black carbon on the distribution of polycyclic aromatic hydrocarbons (PAHs) was greater than that of organic carbon. The Pearson correlation coefficient between PAHs and available potassium was 0.319, which was significantly positive correlation. The correlation coefficient of Pearson with total nitrogen was 0.673, and the correlation coefficient between soil clay percentage and polycyclic aromatic hydrocarbons (PAHs) was 0.654. The adsorption of phenanthrene on urban forestry soils in Nanjing can be fitted by Linear linear distribution model and Freundlich model. The adsorption intensity of polycyclic aromatic hydrocarbons (PAHs) phenanthrene on soils in different functional areas of urban forestry is as follows: the forest in the suburbs of the green belt of urban flyover road. The adsorption intensity of different soil layers is the surface layer and the lower layer. The increase of water content and pH value will make the adsorption ability of phenanthrene decrease. The organic carbon content and black carbon content were positively correlated with the adsorption partition coefficient (KD), the correlation coefficients were 0.837 and 0.875; The correlation coefficient between soil clay percentage and KD Pearson was 0.827, which was significantly positive correlation.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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