莫莫格湿地土壤重金属生态风险评价研究

发布时间：2018-02-16 13:45

本文关键词： 莫莫格湿地土壤重金属生态风险评价　出处：《东北师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：湿地具有重要的生态与社会经济价值,在工农业发展、城市化过程中,出现了开垦湿地为农田、过度捕捞、建筑侵占湿地及盲目发展旅游等破坏湿地的行为,给湿地生态系统带来了多方面的不利影响。土壤是湿地生态系统生命的载体,不合理地施用化肥和农药、随意处置生活垃圾等人类活动均可能使湿地土壤中重金属含量上升。因此,定期开展湿地土壤重金属污染与风险评价对保护与合理利用湿地具有重要的科学意义。本文以莫莫格湿地为研究对象,通过野外采样和室内实验,利用多元统计分析方法和GIS技术系统研究了该湿地土壤重金属的含量特征、来源,并采用多种土壤环境质量和潜在生态风险评价方法评价了湿地土壤重金属污染现状及其潜在生态风险程度。主要研究结论如下:莫莫格湿地土壤中6种重金属的含量顺序表现为ZnCrPbNiCuCd。Cu、Zn、Cd的平均含量高于当地土壤环境背景值,Pb、Cr、Ni的平均含量与背景值基本持平。除了Cd的平均含量略高于国家《土壤环境质量标准》一级标准外,其余5种重金属均在标准范围内。说明莫莫格湿地Cd积累比较明显。基于多元统计分析的来源解析结果表明,描述性统计分析、相关性分析、主成分分析、聚类分析的结果较为一致,可以互相验证。其结果表明,研究区土壤中Pb、Ni、Cu、Cr、Zn与TP、有机质的相关关系较为显著,Cd与TN相关关系较为显著,Pb、Ni、Cu、Cr、Zn主要受地球化学背景值的影响,而Cd主要来源于人为源,受人类活动影响较大。分别根据当地土壤背景值和土壤环境质量一级标准,采用单因子指数法、内梅罗综合指数法、地累积指数法和潜在生态风险指数法对莫莫格湿地土壤重金属污染现状及潜在生态风险进行了评价。结果显示,研究区Pb、Ni、Cr积累程度较轻,而Cu、Zn、Cd则存在一定程度的积累,尤以Cd最为明显。内梅罗指数法评价结果表明研究区域整体处于警戒限等级污染程度。采用地累积指数法对土壤重金属污染的评价结果轻于单因子污染指数法所得结果。从生态风险角度来看,整个研究区域处于轻微生态风险程度,但Cd单项潜在生态风险处于强生态风险等级,需引起重视。针对Cd的生态风险情况,本研究探讨了土壤重金属尤其是Cd的防治对策,给湿地土壤重金属污染防治与管理提供参考。
[Abstract]:Wetland has important ecological and social economic value. In the process of industry and agriculture development and urbanization, wetland reclamation for farmland, overfishing, construction and occupation of wetland and blind development of tourism and other acts of destruction of wetlands. Soil is the carrier of wetland ecosystem life, fertilizer and pesticide are applied unreasonably. Human activities, such as random disposal of domestic waste, may increase the content of heavy metals in wetland soils. It is of great scientific significance to carry out regular heavy metal pollution and risk assessment in wetland soil for the protection and rational utilization of wetlands. This paper takes the Molmoger wetland as the research object, through field sampling and laboratory experiments. The contents and sources of heavy metals in the wetland soil were studied by using multivariate statistical analysis method and GIS technique. The present situation and potential ecological risk degree of heavy metal pollution in wetland soil were evaluated by using various methods of soil environmental quality and potential ecological risk assessment. The main conclusions are as follows:. The order of content is that the average content of ZnCrPbNiCuCd.CuOZnU CD is higher than that of the local soil environment background value. The other five heavy metals were all within the standard range, which indicated that CD accumulation in Molog wetland was obvious. The results of source analysis based on multivariate statistical analysis showed that descriptive statistical analysis, correlation analysis, principal component analysis, The results of cluster analysis are consistent and can be verified by each other. The results show that the correlation between Pb ~ (2 +) ~ (2 +) and Cu ~ (2 +) Cr ~ (2 +) Zn and TP, and the correlation of organic matter between CD and TN are more significant, and the correlation between CD and TN is more significant, and the geochemical background value mainly influences the relationship between Pb ~ (2 +) and Ni ~ (2 +). According to the local soil background value and the first grade standard of soil environmental quality, single factor index method and Nemero comprehensive index method were used. The present situation and potential ecological risk of heavy metal pollution in soil of Momogel wetland were evaluated by the method of land accumulation index and potential ecological risk. The results showed that the accumulation of Pb ~ (2 +) ~ (2 +) Ni ~ (2 +) Cr in the study area was less than that of Cu ~ (2 +) Zn ~ (2 +) CD. In particular, CD was the most obvious. The result of Nemero index method showed that the whole area was in the critical level of pollution. The results of soil heavy metal pollution by using the ground accumulation index method were less than that by single factor pollution index method. From the perspective of ecological risk, The whole study area is in the degree of slight ecological risk, but the single potential ecological risk of CD is in the grade of strong ecological risk, which needs to be paid attention to. In view of the ecological risk of CD, the control countermeasures of soil heavy metals, especially CD, are discussed in this study. It provides reference for the prevention and management of heavy metal pollution in wetland soil.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X825

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