基于社会—生态系统框架的土壤重金属风险分区与防控对策研究

发布时间：2018-08-26 13:09

【摘要】：目前我国耕地环境质量总体状况不容乐观,受污染耕地的面积约3.5亿亩,其中土壤重金属污染为主要污染类型。随着环保法治力度加强,点源污染得到有效遏制,区域土壤重金属面源污染防控成为研究的重点领域,由于人类活动历史悠久和土地利用系统分异造就了都市区复杂的人地关系。本文从区域宏观社会-生态系统(人地关系)视角切入,以国际性大都市—北京市的土壤重金属为研究对象,以“构建土壤重金属社会-生态系统综合风险管理框架—实证分析”为主体思路,沿着“时空变异特征分析——土壤重金属累积与土地利用格局关系——土壤重金属社会-生态系统功能分区—风险防控对策与政策保障体系”为实证思路,开展了区域土壤重金属风险分区与防控对策研究。研究成果如下： (1)土壤重金属社会-生态系统综合风险管理框架由外部驱动子系统、内生驱动子系统和土地利用系统表征三部分组成,资源系统、资源单元、利益相关者和管控系统是区域土壤重金属协同演化和不确定问题分析的主体。区域土壤重金属综合属性以人地关系为驱动、土地利用系统为表征、物质流传递为向量,并从宏观层面提出了区域土壤重金属风险控制技术体系。 (2)利用GIS空间分析技术和数理统计方法,初步分析了北京市1985-2006年20年间Ni、Cr、 Zn和Hg含量和Cu、 As、 Cd和Pb污染风险等级的时空变化特征。结果表明：土壤重金属含量在1985-2006年问空间累积程度差异显著,其中Hg元素累积效应强烈,且与城市用地空间拓展路径相似；Cr、Zn、 Ni局部地区有上升趋势,属于潜在污染风险元素；Cd、 Pb、 AsCu污染风险等级均有上升趋势。 (3)在GIS支持下,对土壤重金属累积和土地利用空间格局进行定量化研究,提取不同重金属累积等级下的土地利用景观格局特征,揭示景观格局对土壤重金属累积的贡献率。结果表明：不同土壤重金属之间的土地利用空间格局类型差异显著。Cr和Ni的高值主要分布在采矿用地附近,而城市化地区的土壤重金属富集明显,尤其是Hg, Pb和Cd。在农业集约化地区同样出现了高累积水平的土壤重金属,如As, Cu和Zn。不同重金属元素在不同社会-生态过程呈现不同的富集特征,成土母质为主要来源的元素(如Cr和Ni)高值分布在景观斑块大且形状简单的区域,相反,受人类活动控制的元素(如Hg, Pb, Cu, As, Cd和Zn)高值区主要存在于景观类型丰富、多样和破碎的区域。景观格局特征对土壤重金属富集的贡献度达71.24%。 (4)提出土壤重金属社会-生态类型区概念(social-ecological patterns of heavy metals, SEPHM),采用符合社会-生态类型区协同演化规律的自组织映射网络模型(SOM)为工具,实现北京市乡镇尺度“自下而上”与“自上而下”的重金属管理分区。北京市土壤重金属累积的主要因子为人口密度、植被指数、工矿用地密度和道路密度。土壤重金属社会-生态类型区可分为三大类九亚类,且类型区与北京市主体功能区规划相衔接,具有现实可操作性。在综合上述研究分析的基础上,提出北京市土壤重金属污染风险防控对策与政策保障体系。主要内容为：以国土空间规划为技术手段的重金属联防联控；以产业结构布局和分区管制为重的重金属源头控制；以市场经济为导向的土壤污染修复产业平台搭建；以政府为主导的“一揽子”政策法治保障机制。
[Abstract]:At present, the overall situation of cultivated land environmental quality in China is not optimistic. The area of polluted cultivated land is about 350 million mu, of which heavy metal pollution is the main pollution type. From the perspective of regional macro-social-ecological system (man-land relationship), this paper takes the soil heavy metals in Beijing, an international metropolis, as the research object, and focuses on "building a comprehensive risk management framework of soil heavy metals society-ecological System-Empirical analysis". Based on the analysis of spatial-temporal variability characteristics, the relationship between soil heavy metal accumulation and land use pattern, the social-ecosystem functional zoning of soil heavy metals, the risk prevention and control countermeasures and the policy guarantee system, the regional soil heavy metal risk zoning and prevention and control countermeasures were carried out.
(1) The framework of soil heavy metal social-ecosystem integrated risk management consists of three subsystems: external drive subsystem, endogenous drive subsystem and land use system. Resource system, resource unit, stakeholders and management and control system are the main parts of regional soil heavy metal co-evolution and uncertainty analysis. The comprehensive attributes are driven by man-land relationship, represented by land use system, and vector by material flow. A regional soil heavy metal risk control technology system is proposed from the macro level.
(2) The spatial and temporal variations of Ni, Cr, Zn and Hg contents and Cu, As, Cd and Pb pollution risk grades in Beijing during the 20 years 1985-2006 were preliminarily analyzed by means of GIS spatial analysis and mathematical statistics. The spatial expansion path of urban land is similar; Cr, Zn, Ni are rising in some areas, which belong to potential pollution risk elements; Cd, Pb, AsCu pollution risk levels have an upward trend.
(3) Quantitative study on soil heavy metal accumulation and land use spatial pattern was carried out with the support of GIS. Landscape pattern characteristics of land use under different heavy metal accumulation levels were extracted to reveal the contribution rate of landscape pattern to soil heavy metal accumulation. Significant. The high values of Cr and Ni are mainly distributed in the vicinity of mining land, while the soil heavy metals in urbanized areas are obviously enriched, especially Hg, Pb and Cd. Soil heavy metals with high accumulation levels, such as As, Cu and Zn, also appear in agricultural intensive areas. High values of parent materials (such as Cr and Ni) were mainly distributed in large and simple landscape patches. On the contrary, high values of elements (such as Hg, Pb, Cu, As, Cd and Zn) controlled by human activities mainly existed in areas rich in landscape types, diverse and fragmented. Landscape pattern characteristics contributed 71.24% to soil heavy metal enrichment.
(4) The concept of social-ecological patterns of heavy metals (SEPHM) was put forward, and the self-organizing mapping network model (SOM) was used as a tool to realize the "bottom-up" and "top-down" heavy metals management zoning at township level in Beijing. The main factors of accumulation of heavy metals in urban soils are population density, vegetation index, industrial and mining land density and road density.
On the basis of the above research and analysis, the countermeasures and policy guarantee system of soil heavy metal pollution risk prevention and control in Beijing were put forward. The platform for pollution remediation industry is set up, and the "government package" policy protection mechanism under the rule of law is adopted.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X53

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