广元市周边废弃煤矿酸性矿井涌水水质分析及地下水健康风险评价

Water quality analysis and groundwater health risk assessment of acid mine inflow from abandoned coal mines around Guangyuan City

  • 摘要: 为揭示酸性矿山废水对其周边地下水和地表水水质构成的影响,以及地下水中金属元素对人体健康的潜在危害,以广元市周边废弃煤矿为研究区域,对区域内23个地下水样品和39个地表水样品中的常规指标和金属元素进行测定和分析。基于内梅罗综合指数法和污染指数法分析研究区地下水及地表水环境质量,应用健康风险评价模型评价研究区地下水健康风险。结果表明:研究区范围内地表水中的TDS(总溶解性固体物质)、SO4 2−、Ca2+和Mg2+浓度较高,其中TDS和SO4 2−平均浓度最高,超过GB 3838—2002《地表水环境质量标准》Ⅲ类限值。研究区范围内地下水水质较差,SO4 2−、TDS、Mg2+、Ca2+浓度较高,其中SO4 2−以及TDS的平均浓度最高;地下水的金属元素平均浓度的大小顺序为TFe(Fe2+、Fe3+总和)>Al>Pb>Zn>Mn>Cu>TCr(Cr3+、Cr6+总和)>Cd>As>Hg,有9种金属元素超过GB/T 14848—2017《地下水质量标准》Ⅲ类限值;从地下水的金属元素浓度空间分布来看,东部地区高于西部地区,旺苍县地下水水质受重金属污染最为严重。内梅罗指数评价结果显示,大部分地表水评价结果为良好或极好,少部分为较差或极差,这与污染指数评价结果具有较好的一致性,主要由矿井涌水排放导致。健康风险评价结果表明,研究区地下水健康总风险较高,主要来源于致癌性元素As、Cd和Cr,致癌风险均高于最大限值(10−4),非致癌总风险均大于可接受的健康风险最大限值(1),表明地下水具有较为严重的非致癌健康风险;研究区地下水经口暴露途径出现的潜在非致癌风险超过皮肤暴露途径,且成年人的潜在非致癌风险高于儿童。研究区范围内地下水水质存在较大健康风险,该类水体不宜饮用,在日后使用过程中应重点防控重金属Al、Pb、Zn和Fe引致的风险。

     

    Abstract: The abandoned coal mines around Guangyuan City were taken as the study area to reveal the impact of acid mine wastewater on the water quality composition of its surrounding groundwater and surface water, as well as the potential hazard of metal element in the groundwater to human health, The conventional index and metal elements in 23 groundwater samples and 39 surface water samples in the target region were determined and analyzed. The environmental quality of groundwater and surface water in the study area was analyzed on the basis of the Nemero comprehensive index method and the pollution index method, and the health risk assessment model was applied to evaluate the health risk of groundwater in the study area. The research showed that the groundwater within the study area contained a high level of total dissolved solids (TDS), SO4 2−, Ca2+ and Mg2+ with the highest average mass concentration of TDS and SO4 2−, which exceeded Class Ⅲ limits in Environmental Quality Standards for Surface Water (GB 3838-2002). In addition, high levels of TDS, SO4 2−, Ca2+ and Mg2+ caused poor groundwater quality. Among the above elements, SO4 2−and TDS had the highest average mass concentrations. The average concentrations of heavy metals in the studied groundwater were in the following order: TFe (sum of Fe2+and Fe3+) > Al3+>Pb2+>Zn2+>Mn2+>Cu2+>TCr (sum of Cr3+ and Cr6+)>Cd2+>As>Hg, with nine heavy metals exceeding Class Ⅲ limits in Standard for Groundwater Quality (GB/T 14848-2017). According to the results, the eastern region had more metal element in its groundwater than the west; and the groundwater quality in Wangcang County was the most seriously polluted by heavy metals. According to the Nemero index evaluation, most surface water evaluation results were good or excellent, and a few were poor or very poor. This was in good agreement with the pollution index evaluation results, which indicated that the pollution was mainly caused by the discharge of mine water inflow. According to the health risk evaluation results, the groundwater in the study area had a high health risk. The main carcinogenic elements were As, Cd and Cr. The carcinogenic risk of these three elements was all above the maximum risk limit of 10−4. Meanwhile, the total non-carcinogenic risk of the groundwater exceeded 1 (the acceptable health risk limit), indicating a serious risk of non-carcinogenic disease. The potential non-carcinogenic risk from oral exposure to groundwater in the survey area exceeded that of skin exposure, and the adults bore higher potential non-carcinogenic risk than minors. The results of this study indicated that the quality of groundwater within the study area posed a great threat to people’s health, and the groundwater in the study area was not suitable for drinking. As for the future use of the water bodies, more significance should be attached to the prevention and control of risk from the heavy metals Al, Pb, Zn and Fe.

     

/

返回文章
返回