吐鲁番盆地葡萄园土壤重金属污染及其潜在健康风险

Contamination and potential health risk of heavy metals in vineyard soil in Turpan Basin

  • 摘要:
    背景  农用地土壤环境质量与农产品质量安全有着密切的关系。在区域农业集约化背景下,具有生理毒性的重金属元素进入土壤生态系统会导致土壤环境恶化、功能失调等一系列土壤环境安全问题。
    目的  分析中国葡萄主产区土壤重金属污染水平与分布规律,并评价其潜在人体健康风险。
    方法  采集新疆吐鲁番盆地葡萄园101个采样点的土壤样品,分析其中砷(As)、镉(Cd)、铬(Cr)、镍(Ni)、铅(Pb)和汞(Hg)元素的含量,并与GB 15618-2018《土壤环境质量标准农用地土壤污染风险管控标准(试行)》进行比较。采用Nemerow污染指数(NPI)和美国环境保护署健康风险评价模型对葡萄园土壤重金属污染及其潜在健康风险进行评价。
    结果  吐鲁番盆地葡萄园土壤中As、Cd、Cr、Ni、Pb和Hg元素质量分数平均值分别为9.57、0.19、59.0、21.60、13.41、0.045 mg·kg-1,均低于GB 15618-2018中的限值,但As、Cd、Cr和Hg质量分数平均值均高于新疆灌耕土背景值。葡萄园土壤重金属元素单项污染指数(Pi)平均值从高到低依次为Cd(1.54)、Cr(1.49)、Hg(1.16)、As(1.05)、Pb(0.99)和Ni(0.82),其中Cd、Cr、Hg和As处于轻度污染态势(1 < Pi ≤ 2),Pb和Ni处于预警态势(0.7 < Pi ≤ 1);6种重金属的NPI平均值为1.53,处于轻度污染状态(1 < NPI ≤ 2)。葡萄园土壤中6种重金属元素的非致癌风险非致癌风险指数(HI) < 1和致癌风险致癌风险指数(TCR) < 1×10-6均为可忽略水平。不同暴露途径中,各金属元素经手-口摄入的非致癌风险商(HQ)和致癌风险商(CR)均最高。6种重金属元素对儿童的非致癌和致癌风险均高于成人。
    结论  研究区葡萄园土壤中6种重金属元素通过手-口摄入、呼吸吸入、皮肤接触3种暴露途径的致癌和非致癌风险均处于安全范围内。

     

    Abstract:
    Background  The environmental quality of agricultural land soils is closely related to the quality and safety of agricultural products. With the regional agricultural intensification, a series of soil environmental safety problems, such as soil degradation and dysfunction, are caused by toxic heavy metal elements entering into the soil ecosystem.
    Objective  This study aims to understand the pollution levels and distribution patterns of heavy metals in vineyard soil in a main grape production area in China, and evaluate their potential human health risks.
    Methods  A total of 101 soil samples from vineyard in Turpan Basin were collected for analyzing the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and mercury (Hg). The detected concentrations were compared with the Soil environment quality-Risk control standard for soil contamination of agriculture land (GB 15618-2018). The contamination levels and potential health risks of the six heavy metals in vineyard soil were analyzed based on the Nemerow pollution index (NPI) and the US Environmental Protection Agency Health Risk Assessment Model.
    Results  The average concentrations of As, Cd, Cr, Ni, Pb, and Hg in vineyard soil in Turpan Basin were 9.57, 0.19, 59.0, 21.60, 13.41, and 0.045 mg·kg-1, respectively, and all were lower than the national limits (GB 15618-2018), but the average concentrations of As, Cd, Cr, and Hg exceeded the background values of irrigation soil in Xinjiang. The average values of single contamination factor (Pi) for each heavy metal element from high to low were Cd (1.54) > Cr (1.49) > Hg (1.16) > As (1.05) > Pb (0.99) > Ni (0.82). Among them, the vineyard soil was mildly polluted by Cd, Cr, Hg, and As (1 < Pi ≤ 2), and slightly polluted by Ni and Pb (0.7 < Pi ≤ 1, warning line). The average value of NPI for the vineyard soil was 1.53 and suggested the soil was mildly polluted (1 < NPI ≤ 2). Both the non-carcinogenichazard index (HI) < 1 and carcinogenictotal carcinogenic risk (TCR) < 1×10-6 health risks of selected six heavy metal elements in vineyard soil showed a negligible risk level. The hazard quotients (HQ) and carcinogenic risks (CR) of selected heavy metal elements via hand-mouth ingestion were the highest among various exposure pathways. Both the non-carcinogenic and carcinogenic health risks of selected heavy metals for children were higher than those for adults.
    Conclusion  The potential health risks caused by exposure through three pathways such as hand-mouth ingestion, inhalation, and skin contact to selected six heavy metal elements in vineyard soil in the study area are in safety scales.

     

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