【作者】 刘波；

【导师】 冯学智；

【作者基本信息】 南京大学 ， 地图学与地理信息系统， 2010， 博士

【摘要】 人类历史就是人类对自然作用强度不断加强的过程,上壤作为人类生产和生活的载体,人类活动必然在土壤中留下印迹,特别是近代工业和高强度的集约化农业生产活动对土壤的物理和化学属性都产生了一些负面的影响。本论文研究在国家重点基础研究发展规划(973)项目《长江珠江三角洲地区土壤和大气环境质量变化规律与调控原理》之第10课题《典型区土壤和作物中重要化学物质的时空分布规律和风险预测》的支持下,选择快速工业化、城市化和高度农业集约化的昆山市为研究区,通过野外采样分析上壤样品中的重金属含量及土壤理化参数,统计分析了影响各种土壤重金属含量的理化参数,同时运用差异显著性检验理论分析了不同产业区和地形区各种土壤重金属的差异性,探讨不同产业活动对土壤的影响；并应用地统计学和克里格方法对昆山的重金属含量和生态风险的空间分布特征进行分析与评价；最后运用统计学方法和因子克里格分析了昆山市土壤重金属主要来源,以确定人类活动对昆山土壤重金属含量的影响程度。主要得到以下结论：1.上壤的理化参数是影响上壤重金属含量的重要因素,但土壤理化参数并不能完全解释土壤重金属的差异来源,不同产业区的上壤重金属含量差异显著性分析表明人类活动是影响土壤重金属污染的重要原因,不同地形区的土壤重金属含量差异显著性分析认为地形因了影响多数土壤重金属的空间分布,并导致综合污染指数在不同地形区也表现出比较显著的差异。2.在上壤重金属的单因索污染分析的基础上,利用内梅罗综合污染指数分析表明：昆山市所有土壤样本都不同程度地受到了重金属污染,其中少量样本重度污染,绝大多数样本中度污染,部分土壤处于轻度污染。3.对昆山重金属元素含量的结构性特征进行了分析表明：昆山市上壤中的Hg、Cu、Ni、Pb等含量具有明显的空间自相关；Zn和Cd具有中等空间自相关；采用普通克里格和协同克里格方法对昆山市土壤重金属的空间分布格局进行分析,协同克里格的预测精度要略高于普通克里格,但两种方法的预测结果空间结构相似：Hg页则以中部含量较高,As含量超标区域主要集中在该区西南角方向,Cr、Cu、Ni、Pb和Zn的高值分布在东北角和西南角。4.结合主成分分析和因子克里格法对上壤重金属源解析表明：昆山土壤的重金属含量受人类活动的扰动较大,有外源进入土壤,并且.污染程度已经比较严重,其中以Hg、Cd的污染程度量最大,As、Pb、Zn也有了较为严重的污染,Cr和土壤背景值较接近,超标率和污染指数也较小,可认为除局部地区有点源污染外基本没有外源进入土壤。化工行业的污水灌溉为昆山土壤Hg、Cd、Pb污染的主要来源,印染行业为昆山土壤的Cr、Ni污染的主要来源,电子行业为昆山土壤Zn、Cu污染的主要来源,冶金、电镀行业对昆山的Hg、Cd、Pb、Cr、 Ni、Zn、Cu污染都有影响。昆山土壤中的As污染原因不明,但是它的分布受河流、湖泊的分布的影响,一般湖泊、河流密集区As的含量较高。5.通过污染重金属元素的对数正态分布图存在的拐点,揭示了元素分别来自不同的总体,运用来源组分分离法量化了重金属不同的来源及其比重,As、Cu、Hg元素人为强干扰组分比重较大,超过30%。6.昆山市土壤重金属污染的生态风险分析表明：As、Zn、Cu、Cr、Ni等5利,重金属元素126个样点的生态风险评价全部处于轻微危害以下等级；Cd元素84.9%的样点处于中等危害等级,强危害和极强危害的样点分别为2.4%和1.6%; Hg污染所造成的生态风险主要表现为中等危害和强危害,分别占45.2%和42.1%,很强危害和极强危害的样点分别占5.6%和0.8%。因此,昆山土壤重金属污染生态风险压力主要来自Cd和Hg。从生态风险的空间分布来看,Pb、Cu、Hg、Cr、Cd和RI的空间分布格局相似,高值区均出现在东部的蓬朗镇,这种分布格局与昆山市的生产力布局具有很强的地域相关性。RI指数等级主要处于中等危害等级,该等级样点占全部样点数的82.5%,另有6.3%的样点的RI指数处于强危害等级,没有样点处于很强危害等级。更多还原

【Abstract】 In recent years, there are greatly impacts in the soil environment with high strength human actives, and the problem of heavy metal pollution in soil environment becomes more and more serious, especially in the Yangtze River Delta, the area of intense absence resources and rapidly economic development, therefore, heavy metal pollution arouses widely attention by human beings. Kunshan city, located in Yangtze River Delta has experienced a rapidly industrialization, urbanlization and intensive cultivation in agriculture in the recent30years. Study on the heavy metal pollution status in Kunshan City with multi-variances and factor kriging analysis will help us understanding the potential risk on ecosystem from heavy metal pollution and the pollution sources. The study can also provide some reference to the continuable application and management with soil resources. The following results were obtained.(1)Analysis on the heavy metal pollution degree showed that all soil samples collected in Kunshan City were polluted by heavy metal in different degree. Few of them are in serious pollution status, most of them are in medium pollution and part of them are in low-grade pollution by heavy metal. Though the soil physical and chemical characters have showed some relation to the heavy metal content, they can’t account for all the difference of heavy metal content. The exterior factors, especially human activities can be the most important factor that caused the increasing of heavy metal content.(2) Otherness verification analysis on the heavy metal content and pollution index in the sampled soil showed apparent difference in the soil samples collected in the region with different topographty for most of the heavy metals in the study; the otherness verification analysis also showed that the heavy metal content has difference for different product region. It is remarkable for the Hg difference between the region of chemical plant and printing plant, and Cr difference between the region of printing plant, smelting plant and chemical plant.(3)Analysis on the spatial structure of these heavy metal with geo-statistical method showed that the content of Hg, Cu, Ni and Pb were moderately auto-correlated in a given spatial range. With the selected model, ordinary Kridging interpolation method were used as interpolation strategy to study the heavy metal content spatial pattern with the Geostatistics module provided by ArcGIS9.2software. It showed that Hg content is high in the central Kunshan city and showed a belt with high content in the north of Kunshan city. And the region with high As content are mainly located in the southwest of Kunshan.(4)The analysis on the sources of heavy metal in the soils showed some feature of exterior source for heavy metals. The pollution is serious from Hg and Cd. And the pollution from As, Pb and Zn are also upper. Only content of Cr in the soil samples are similar to soil background. The irrigation with sullage is the main source of Hg, Cd and Pb; printing plant can account for most of the pollution of Cr and Ni; electron plant has bring most of the Zn and Cu pollution. And the smelting and electroplating have some effects on the content of Hg, Cd, Pb, Cr, Ni, Zn and Cu in the soil of Kunshan City. The As pollution has some relation with the waterbody distribution. The content of As is higher in the regions with a higher density of rivers and lakes.(5)Ecosystem risk from As, Zn, Cu, Cr and Ni are in trivial-grade currently for all the126samples, but Ecosystem risk from Cd for84.9percent samples are in moderate-grade status,2.4percent of them are high-grade and1.6percent of them are in very-high-grade. The ecosystem risk from Hg are mainly in moderate and high grade. The ecosystem is mainly loading the pressure from Cd and Hg contamination. The spatial pattern of risk index for Pb, Cu, Hg, Cr and Cd showed similar because the high risk region are mainly located in the Penglang township. It can be accounted by the industry distribution. Several sources of heavy metals can be explained by log accumulated probability figure.更多还原