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    陕西潼关县金矿矿区周边农田土壤重金属生态健康风险评价

    Ecolcgical and health risk assessment of heavy metals in farmland soil around the gold mining area in Tongguan of Shaanxi Province

    • 摘要: 为了解潼关金矿矿区早期粗放式的矿业活动对矿区周边农田土壤的重金属污染状况的影响以及对暴露人群的不良健康效应的评价,采用地质调查工程选取了矿区附近6块农田土壤为研究对象,通过X射线荧光光谱分析法测定了68个土壤样本中Cd、Hg、As、Pb、Cr、Cu、Ni、Zn等8种土壤重金属含量,采用地累积指数法、潜在生态危害指数法和健康风险评估模型分别评价该区土壤重金属污染程度、潜在生态风险和人体健康风险。结果表明,该区农田土壤中Cd、Hg、Pb、Cu、Ni、Zn 6种重金属平均值高于潼关县土壤背景值,呈现不同程度的积累;Pb、Hg、Cd的土壤积累含量不仅超出了土壤重金属污染对农产品质量存在安全风险的最低限值农用地土壤污染风险筛选值,还分别以41.2%、72.1%、14.7%的超标率超出了土壤重金属污染对农产品质量存在安全风险的最高限值农用地土壤污染风险管制值;研究区土壤重金属污染评价显示,土壤中Hg、Cd、Pb总体污染程度最重,Cu、Zn总体呈现轻—重污染,Ni、Cr、As总体呈现无污染状态。生态风险评价显示,Hg、Cd、Pb为主要生态危害元素,Hg为极强风险,Cd和Pb为强风险。人体健康风险表明,研究区重金属对儿童的非致癌风险显著,Pb、Hg为主要非致癌因子;致癌风险均在合理范围,Cd致癌风险最大,手-口摄入为最主要的暴露途经,儿童更易受到重金属污染威胁。

       

      Abstract: In order to understand the impact of the early extensive mining activities in the Tongguan gold mine on the heavy metal pollution of the farmland soil and the evaluation of the adverse health effects of the exposed population, enginnering six farmland soils near the mine area were selected as the research object in the geological survey. Spectral analysis method was used to determine the contents of Cd, Hg, As, Pb, Cr, Cu, Ni, Zn and other 8 soil heavy metals of 68 soil samples. The soil accumulation index method, potential ecological hazard index method and health risk assessment model were used to evaluate the soil heavy metal pollution degree, potential ecological risk and human health risk in the area. The results show that the average values of Ni, Hg, Cd, Zn, Pb and Cu in the farmland soil in this area are higher than the soil background value of Tongguan County, indicating different levels of accumulation. The accumulated soil content of Pb, Hg, and Cd not only exceeds the minimum limit of the safety risk of heavy metal pollution, bu also exceeds the maximum limit of the safety risk of heavy metal pollution on the quality of agricultural products by 41.2%, 72.1%, and 14.7% of the exceedance rates respectively. The evaluation of soil heavy metal pollution in the study area shows that the total pollution degree of Hg, Cd and Pb in the soil is the heaviest, Cu and Zn are generally light to heavy pollution, and Ni, Cr and As are generally pollution-free. The ecological risk assessment shows that Hg, Cd, and Pb are the main ecological hazard elements, Hg is a very strong risk, and Cd and Pb are strong risks. Human health risks show that the non-carcinogenic risk of heavy metals to children is obvious, and Pb and Hg are the main non-carcinogenic factors. Carcinogenic risks are within a reasonable range. Cd is the most carcinogenic risk, and hand-mouth intake is the most important exposure route. Children are more vulnerable to heavy metal pollution.

       

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