城郊农用地土壤重金属来源解析与生态风险评价——以保定市涞源县为例
Source analysis and ecological risk assessment of heavy metals in suburban agricultural land soil: A case study of Laiyuan County of Baoding City
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摘要: 城郊农用地土壤中重金属含量呈现不断累积趋势, 为深入研究此类典型区域中土壤重金属的来源特征及所产生的生态风险, 选取保定市涞源县作为研究区, 系统采集地表 0~20 cm范围内的土壤样品, 分析测定样品的重金属元素含量及pH值。选取相关性分析、主成分分析等统计学方法对研究区内重金属元素的分布情况进行研究。采用单因子指数法、内梅罗综合污染指数法研究重金属污染特征, 并根据Hakanson潜在生态风险指数法对区域内土壤生态风险现状进行评价。结果表明: 土壤中Cd、Hg、Pb、Zn的含量特征反映了人类活动对土壤的影响, 而As、Cr、Ni、Cu主要受到地质背景因素的控制; 研究区重金属元素表现较为清洁, 土壤环境现状整体良好, 潜在生态风险较低, 土壤重金属不会对农产品质量和人类健康产生危害, 但人为因素对土壤环境有一定负面作用, 应采取措施防止重金属持续累积。研究成果可为城郊农用地的土壤环境保护工作提供科学依据。Abstract: The heavy element contents in the soil of suburban agricultural land shows continuous accumulation trend. Laiyuan County of Baoding City was selected as the study area to further study the source characteristics and ecological risks of heavy metals in soil of such typical areas. The surface (0 ~ 20 cm) soil samples were systematically collected to analyze and determine the heavy metal element contents and pH value of the samples. Statistical methods, such as correlation analysis and principal component analysis, were used to study the distribution of heavy metal elements in the study area. The single factor index method and Nemerow comprehensive pollution index method were used to study the characteristics of heavy metal pollution, and the ecological risk status of soil in the region was evaluated according to the potential ecological risk index method proposed by Hakanson. The results show that the content characteristics of Cd, Hg, Pb and Zn in soil reflect the influence of human activities on soil, while As, Cr, Ni and Cu are mainly controlled by geological background factors. The heavy metal in the study area is clean, and the soil environment condition is good. The potential ecological risk in the surface soil is relatively low, and the heavy metal in soil will not cause harm to agricultural product quality and human health. But the human factors have some negative effects on soil environment, so actions should be taken to avoid the accumulation of heavy metals. The results of this study could provide scientific basis for soil heavy metal pollution prevention and control in suburban agricultural land.
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