山西某火力发电厂周边农田土壤重金属污染评价

    Evaluation of Heavy Metal Pollution in Farmland Around a Thermal Power Plant in Shanxi Province.

    • 摘要: 为了探明山西某火力发电厂对周边农田土壤重金属污染的影响,采集了27个土壤样品,测定了样品中Cd、Cr、Cu、Hg、Mn、Ni、Pb和Zn 8种重金属含量,并从元素含量特征、相关性和表层分布3个方面进行土壤污染评价。结果表明,研究区土壤样品中,8种重金属元素的平均含量均低于GB 15618-2018《土壤环境质量农用地土壤风险管控标准(试行)》中风险筛选值,但以山西土壤环境背景值为依据,Cd、Cr、Cu、Hg、Mn、Ni、Pb和Zn的超标率分别为100%、93%、100%、44%、93%、15%、96%和78%。单因子污染指数法评价结果表明,以GB 15618-2018为依据,研究区土壤未受到污染;以山西土壤环境背景值为依据,研究区土壤中各重金属元素均有一定程度的积累。内梅罗综合污染指数法评价结果表明,以GB 15618-2018风险筛选值为依据,研究区土壤属于清洁土壤;以山西土壤环境背景值为依据,研究区土壤达到中度累积水平。土壤综合质量指数法评价结果表明,仅中南部1个采样点属轻度污染,其他采样点均属无污染状态。综上所述,该电厂周边农田土壤需要采取有效措施,以避免重金属持续累积对土壤质量和农作物生产造成损害威胁。

       

      Abstract: In order to determine the impact of a thermal power plant in Shanxi Province on the pollution of soil heavy metals in the surrounding farmland, 27 soil samples were collected and the contents of Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn in the samples were determined. The soil pollution was evaluated from the aspects of the characteristics of element contents, the correlation and the distribution in the surface layer. The results show that the average content of eight heavy metal elements were lower than GB 15618-2018 standard in the soil samples of the study area, but higher than the background value of Shanxi soil environment with the exceeding rate of 100%, 93%, 100%, 44%, 93%, 15%, 96% and 78%, respectively. The evaluation result of single factor pollution index method show that the farmland soil around the power plant were not polluted according to GB 15618-2018 standard, but the heavy metal elements in the farmland soil around the power plant were accumulated to a certain extent based on the background value of the soil environment in Shanxi Province. The evaluation result of the comprehensive pollution index method show that the farmland soil around the power plant was at the clean level on the basis of the soil environmental quality standard, but the content of heavy metals reached the moderate cumulative level around the power plant on the basis of Shanxi soil environmental background value. Evaluation results of surface soil comprehensive quality index method around power plant show that only one sample point in the south-central part was slightly polluted, and the rest of the sampling points were in a pollution-free state. In summary, the farmland soil around the power plant needs to take effective measures to avoid the continued accumulation of threats to the soil quality and crop production damage.

       

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