四平市城郊蔬菜地土壤重金属来源及环境风险评价

Sources and Environmental Risk Assessment of Heavy Metal Vegetable Soils in Suburbs of Siping City,China

  • 摘要: 以四平市城郊蔬菜地土壤为研究对象,研究了土壤中Pb、Cu、Cd、As和Hg 5种重金属的含量特征及潜在生态风险和健康风险,并对其来源进行了分析。结果表明:研究区Pb、Cu、Cd、As和Hg含量的平均值分别是背景值的1.32倍、2.38倍、2.52倍、1.59倍和2.72倍,在表层土壤中存在明显的富集。环境风险评价表明:研究区土壤重金属处于中等生态风险水平,其中Hg处于较高生态风险水平。健康风险评价模型对暴露人群经摄食途径引起的重金属健康风险评价表明研究区内居民不存在健康风险。主成分分析表明:Cu、Cd主要来自于农业生产;As与污水灌溉及含As农药的使用有关;Hg主要来源于煤炭燃烧;Pb主要来自于汽车尾气以及工业烟尘的大气沉降。Cu、Cd具有一定的同源性,pH值对Pb、Cd迁移转化的影响较强。

     

    Abstract: In this study, we investigated the concentrations and distribution characteristics of Pb, Cu, Cd, As and Hg in vegetable soils in suburbs of Siping City, and assess potential ecological risk and health risk. The average contents of Pb, Cu, Cd, As and Hg in soils were 1.32, 2.38, 2.52, 1.59 and 2.72 times higher than those of the background values, showing a significant enrichment in the surface soil. The environmental risk assessment showed that the heavy metals posed a medium ecological risk, where as Hg was at a higher ecological risk level. Moreover, we employed a health risk assessment model to evaluate the risk of heavy metals to human via diary and found no health risk to the local residents. The PCA showed that Cu and Cd were mainly from agricultural production; As was related to sewage irrigation with use of As pesticide; Hg mainly came from coal combustion;Pb mainly came from atmospheric deposition of vehicle emission and industrial dust. The correlation analysis showed that Cu and Cd had same source, and pH significantly influenced the transport of Pb and Cd migration and transformation.

     

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