白洋淀内不同土地利用类型土壤重金属分布特征与污染评价

Characteristics and Assessment of Soil Heavy Metal Pollution under Different Land-use Types in the Baiyangdian Wetland

  • 摘要:
      目的  白洋淀作为雄安新区生态共同体的重要组成部分,在“白洋淀生态环境治理和保护规划”中,淀区内陆地将被淹没。为科学评价淹没后陆地对白洋淀水体的环境影响,从淀区不同土地利用类型土壤重金属元素分布特征及污染程度评价两个方面开展了研究工作。
      方法  以淀区内现有陆地0 ~ 20 cm土壤为研究对象,以砷、汞、镉、铬、铅、镍、铜、锌重金属元素为研究要素,以统计分析、污染负荷指数法和地质累计指数法评价为分析手段,对淀区内陆面重金属元素统计特征和污染程度进行分析和评价。
      结果  淀区内陆地土壤重金属元素背景值显著高出区域背景值,污染程度总体为轻度污染;农业用地类型土壤重金属污染元素最多, 铜、镉、汞是本区陆地土壤中背景值高、污染贡献最为显著的元素。
      结论  淀内陆地土壤重金属元素含量均低于国家标准(GB 15618—2018)和(GB 36600—2018)中土壤筛选或管控的标准,环境承载力仍有一定缓冲容量;重金属元素间的相关性特征主要由地质背景因素控制,但也明显受到土地利用类型改变的影响。

     

    Abstract:
      Objective  Baiyangdian is the important part of Xiong An’s ecological community. In the Baiyangdian Ecological Environment Management and Protection Plan, the land will be submerged. In order to evaluate the environmental impact of the submerged land on the Baiyangdian water body, this paper has carried out research work from two aspects: the characteristics of soil heavy metals and the evaluation of pollution degree.
      Method  The contents of As, Hg, Cd, Cr, Pb, Ni and Cu in 0-20 cm soil of different land-use types in Baiyangdian were determined, and the features and pollution levels by the heavy metals were assessed with the methods of statistical analysis, pollution load index and geoaccumulation index.
      Result  The results showed that the background values of heavy metals on the lands in Baiyangdian wetland were higher than those on the regional background value. The degree of pollution was generally light. The heavy metals of Cu, Cd and Hg were higher than those of background value and were the most significant polluted elements in the top soil.
      Conclusion  The heavy metals of the land surface soil have not yet reached the soil screening or control standards, and the environmental carrying capacity still has a certain buffer capacity. The correlation characteristics among heavy metals are mainly controlled by geological background factors, but they are also obviously affected by land-use types.

     

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