沟塘水及其周边浅层地下水中重金属污染特征与健康风险评价

Pollution characteristics and health risk assessment of heavy metals in gully pond water and its surrounding shallow groundwater

  • 摘要: 以河南省某乡4个沟塘水及其周边浅层地下水为研究对象,在丰水期采集样品,测定水中Al、Cr、Mn、Fe、Ni、Cu、Zn、As、Se、Ag、Cd、Hg和Pb 13种重金属元素浓度,并评价沟塘水对其周边浅层地下水水质的影响及潜在健康风险。结果表明:沟塘水中重金属总体为重度污染,其中Mn和Fe浓度超过GB 3838—2002《地表水环境质量标准》中Ⅳ类标准限值,平均超标倍数分别为5.5倍和9.0倍;周边浅层地下水中重金属总体为轻度污染,其中Al、Mn、Fe和Ni浓度超过GB/T 14848—2017《地下水质量标准》中Ⅲ类标准限值;浅层地下水中重金属浓度随着与沟塘距离增加而降低,Al、Cr、Ni、Pb、Mn和Fe浓度与到沟塘距离呈对数负相关关系;儿童和成人通过饮水摄入浅层地下水中13种重金属元素的非致癌健康风险之和分别为0.296和0.309,均小于1(可接受水平);儿童和成人终生暴露Cr、Ni、As、Cd、Pb 5种致癌重金属元素的致癌健康风险之和分别为1.44×10-5和7.52×10-5,超过1.0×10-6(较高致癌健康风险)。研究区沟塘水对其周边浅层地下水有一定的影响,儿童和成人通过饮水途径暴露浅层地下水中重金属的致癌健康风险值得关注。

     

    Abstract: Taking 4 gully ponds water and its surrounding shallow groundwater in a village in Henan Province as the research object, the samples were collected during the wet season, the concentrations of 13 heavy metal elements Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ag, Cd, Hg and Pb in the water were determined, and the impact of gully pond water and its surrounding shallow groundwater quality and potential health risks were evaluated. The results showed that the heavy metals in the gully pond water were heavily polluted, among which the concentrations of Mn and Fe exceeded Class Ⅳ limits of Environmental Quality Standards for Surface Water (GB 3838-2002), and the average exceeding multiples were 5.5 times and 9.0 times, respectively. The heavy metals in the surrounding shallow groundwater were generally slightly polluted. Among them, the concentration of Al, Mn, Fe and Ni exceeded the Class Ⅲ limits of Standard for Groundwater Quality (GB/T 14848-2017). The concentration of heavy metals in the shallow groundwater decreased with the increase of the distance from the pond. The concentrations of 6 heavy metal elements of Al, Cr, Ni, Pb, Mn and Fe had a negative logarithmic relationship with the distance from the pond. The sum of non-carcinogenic risk of children and adults ingesting 13 heavy metal elements in shallow groundwater through drinking water was 0.296 and 0.309, respectively, which were both less than 1 or in the acceptable level. And the carcinogenic risk of lifetime exposure of children and adults to 5 heavy metal elements(Cr、Ni、As、Cd、Pb)was 1.44×10-5 and 7.52×10-5, respectively, which exceeded 1.0×10-6 (a higher health risk of cancer). The gully pond water in the study area had a certain impact on its surrounding shallow groundwater, and the carcinogenic health risks of children and adults exposed to heavy metals in shallow groundwater through drinking water deserved special attention.

     

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