山东省某典型工业城镇土壤重金属污染特征及风险评估

    Contamination characteristics and risk assessment of soil heavy metals in a typical industrial town in Shandong Province, China

    • 摘要: 为探究山东某典型工业城镇土壤重金属污染情况、来源及生态风险,于2022年8~10月采集了499件研究区表层土壤样品,采用经典统计法与空间插值法分析土壤Hg、Cd、As、Pb、Cu、Cr、Zn和Ni重金属含量及其空间分布特征,并运用PCA主成分分析法对研究区重金属进行来源解析,使用污染指数法评价研究区重金属污染水平。结果显示:研究区土壤Hg、Cd、As、Pb含量平均值均超过烟台市土壤重金属背景值,且8种元素均存在高值区域,显示重金属元素呈不同程度富集趋势;变异系数分析表明,除Ni外,其余重金属元素受人类活动影响较大;主成分分析表明,土壤中Cd、Pb、Cu、Zn和Cr主要来源于工业和交通源,As和Hg主要来源于工业、农业和生活源,Ni主要来源于自然条件土壤母质;单因子污染法、地累积指数法和内梅罗污染指数法研究表明,研究区土壤重金属除Hg和Cd外,整体呈无污染和轻微污染,Hg和Cd为研究区污染水平较高的元素;潜在生态风险评价显示,研究区土壤重金属污染整体呈轻微风险等级,少量污染较严重的点位主要分布在工业区周边,工业活动产生的“三废”是周边的土壤重金属富集的主要影响因素。研究区土壤重金属污染整体为中低污染水平,部分土壤重金属含量严重超标,尤其是Hg和Cd为研究区污染程度最重的元素,需引起重视。建议加强工业区周边土壤重金属监测工作,采取科学合理的措施以确保土壤可持续利用。

       

      Abstract: To investigate the contamination, source, and ecological risk of soil heavy metals in a typical industrial town in Shandong Province, China, this study collected 499 topsoil samples from the study area from August to October 2022. The contents and spatial distributions of heavy metals like Hg, Cd, As, Pb, Cu, Cr, Zn, and Ni in the samples were analyzed using classical statistics and spatial interpolation methods. The source apportionment of heavy metals in the study area was explored through the principal component analysis (PCA). The contamination levels of heavy metals in the study area were assessed using the contamination index method. The results indicate that the average contents of Hg, Cd, As, and Pb in soils all exceeded their background values in Yantai City, and high-value zones were observed for all eight elements, indicating various degrees of enrichment. The analysis of coefficients of variation reveals that except for Ni, other heavy metals were significantly influenced by human activities. The PCA suggests that Cd, Pb, Cu, Zn, and Cr originated primarily from industrial and traffic sources. As and Hg were predominantly derived from industrial, agricultural, and domestic sources, while Ni was primarily from natural soil parent materials. The analyses based on the single-factor contamination index, geoaccumulation index, and Nemerow contamination index show that apart from Hg and Cd, other soil heavy metals in the study area exhibited no or slight contamination overall, demonstrating that the study area was principally contaminated by Hg and Cd. The potential ecological risk assessment suggests that the overall heavy metal contamination posed a minor risk level. A few sites with relatively severe contamination were primarily located around the industrial area. The waste gas, wastewater, and industrial residue generated by industrial activities constituted the dominant factor influencing the enrichment of heavy metals in surrounding soils. Overall, soil heavy metal contamination in the study area was at a moderate to low level, with some metals, particularly Hg and Cd, severely exceeding standard levels, warranting attention. It is recommended to strengthen the monitoring of heavy metals in soils around the industrial area, and adopt scientific and reasonable measures to ensure sustainable soil utilization.

       

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