贵州典型乡镇集中式饮用水源重金属分布特征及健康风险评估

Distribution Characteristics and Health Risk Assessment of the Heavy Metals in the Centralized Drinking Water Sources in the Typical Townships of Guizhou Province

  • 摘要: 为揭示贵州典型乡镇饮用水源的重金属分布特征及健康风险水平,于2020年6月、2021年1月采集该区域26个乡镇集中式饮用水源水样,通过对水样中铁、铜、锰、锌、砷、六价铬、汞、铅、镉进行检测,分析其污染水平,并运用美国EPA健康风险评价模型对其进行健康风险的初步评价。结果表明:研究的26个乡镇饮用水源重金属含量均符合《GB 5749—2006生活饮用水卫生标准》要求,总体污染程度较低。季节变化对水源地水体的重金属浓度影响明显,丰水期金属浓度比枯水期高1.0~9.9倍,且岩溶水型水源地水质对季节的影响更为敏感。健康风险评估结果显示,研究区域内水源健康风险以化学致癌风险为主,主要风险因子是砷。重金属的非致癌健康风险数量级为10-12~10-10,致癌健康风险数量级为10-10~10-7,均远低于ICRP和EPA推荐的最大可接受风险水平;饮用水源重金属健康风险按水源地类型排序为河流型>岩溶水型>湖库型。

     

    Abstract: In order to reveal the pollution characteristics and risk levels of the heavy metals in the drinking water sources in the typical townships of Guizhou,26 centralized drinking water samples were collected in June of 2020 and January of 2021 to detect the heavy metal content including Cr6+,Pb,Cd,Hg,Fe,Mn,As,Zn and Cu).The health risk assessment model recommended by the US EPA was adopted to evaluate the health risk caused by heavy metals.The results showed that the heavy metal content in the drinking water sources of the 26 towns all met the requirements of the Drinking Water Sanitation Standard (GB 5749—2006),and the overall pollution degree was relatively low.Seasonal change has a significant impact on the heavy metal concentration in the water source,and the metal concentration in the wet period was 1.0~9.9 times higher than that in the dry season.The water quality in the Karst water resources field was more sensitive to seasonal changes.The health risk assessment results showed that the health risk of water sources in the study area was mainly chemical carcinogenesis risk,and the main risk factor was Arsenic.The health risks caused by non-carcinogenic heavy metals ranged from 10-12 to 10-10,and the health risks caused by carcinogenic heavy metals ranged from 10-10to 10-7,which were well below the maximum acceptable risk levels recommended by ICRP and EPA.The risk value of different kinds of drinking water sources descended in this order of river>karst water>reservoir.

     

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