东天山北坡工业带土壤重金属来源解析及健康风险评价

Source Identification of Soil Heavy Metals and Health Risks Assessment in the Industrial Zone of the Northern Slope of the East Tianshan Mountains

  • 摘要:
    目的 为定量解析东天山北坡工业带中米东区、阜康市、吉木萨尔县和奇台县等地区土壤重金属来源和进行健康风险评价,对该区域68个表层土壤样本中锌(Zn)、铜(Cu)、铬(Cr)、铅(Pb)、汞(Hg)和沈(As)等6种重金属的含量进行分析。
    方法 采用地统计学法、潜在生态风险指数、相关性分析、UNMIX模型和健康风险评价模型(USEPA)与蒙特卡罗模拟相结合的方法进行土壤重金属生态风险评估和来源解析。
    结果 ①研究区土壤除Cu和Cr外,Zn、Pb、Hg和As含量平均值分别超过了新疆土壤背景值的1.19、2.11、3.18和2.90倍,其中As是国家农用地土壤重金属风险筛选值的1.02倍。②从空间分布状况来看,Zn、Pb和Hg主要在研究区的西南部和中南部富集,Cu的高值区主要在西北部和中部,Cr高值区主要分布在研究区的中南部,As的高值区较为分散。③潜在生态风险指数显示98.53%样点的Hg含量、19.12%样点的As含量以及研究区63.25%的样点处于中等风险及以上。④研究区的土壤重金属污染主要来自于交通运输与工业生产组成的混合源、大气沉降源和交通运输与成土母质组成的混合源。⑤研究区的非致癌风险(HI)和致癌风险(TCR)均较高,非致癌风险的影响因子主要是As,致癌风险的影响因子主要是Cr和As。
    结论 Hg和As对研究区生态环境危害较大,As和Cr对人体健康危害较大。

     

    Abstract:
    Objective The aims were to quantitatively analyze the sources of heavy metals in soils and assess health risks in the industrial belt on the northern slope of the East Tianshan Mountains, including Midong District, Fukang City, Jimusaer County, and Qitai County. The study analyzed the concentrations of six heavy metals (Zn, Cu, Cr, Pb, Hg, and As) in 68 surface soil samples from the region.
    Method The geostatistics, potential ecological risk index, correlation analysis, UNMIX model, and health risk assessment models (USEPA) combined with Monte Carlo simulation were employed to evaluate ecological risks of soil heavy metals and identify their sources.
    Result ①Except for Cu and Cr, concentrations of Zn, Pb, Hg, and As in soils exceeded Xinjiang's background values by 1.19, 2.11, 3.18, and 2.90 times, respectively. Meanwhile, As exceeded China's agricultural soil screening values by 1.02 times. ②Spatially, Zn, Pb and Hg were predominantly enriched in the southwest and central-southern parts of the study area, while Cu was concentrated in the northwest and central areas, and Cr accumulated mainly in the central-southern parts. As showed a more scattered distribution. ③The potential ecological risk index showed that Hg content in 98.53% sample sites, As content in 19.12% sample sites and 63.25% sample sites in the study area were at moderate risk or above. ④Soil heavy metal pollution in the study area primarily originated from mixed sources composed of transportation and industrial emissions, atmospheric deposition, and mixed sources from transportation and parent materials for soil formation. ⑤Both non-carcinogenic risk (Hazard Index, HI) and carcinogenic risk (Carcinogenic Risk, TCR) were relatively high in the study area. As was the main contributor to non-carcinogenic risk, while Cr and As were significant contributors to carcinogenic risk.
    Conclusion Hg and As would cause the significant environmental hazards in the study area, while As and Cr would cause substantial health risks to humans.

     

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