某退役铀矿山地下水中铀空间分布特征及其健康风险评价

Spatial Distribution Characteristics and Health Risk Assessment of Uranium in Groundwater of a Decommissioned Uranium Mine

以南方某退役铀矿山为对象,分别在平、丰、枯水期对铀矿山尾矿库下游地下水进行采样分析,查明地下水中典型放射性核素铀的时空分布特征;探究铀存在形式与地下水环境参数间的相关关系;使用健康风险评价模型对不同人群的致癌风险进行分类评估,为铀矿山退役后的地下水环境质量评估提供依据。研究结果表明:尾矿库下游平水期地下水中铀的平均含量最高,为0.14 mg/L,丰水期和枯水期地下水中铀含量较低,浓度在0.017~0.049 mg/L;地下水中铀的主要存在形式有UO_(2)(CO_(3))_(3)^(4-)、UO_(2)(CO_(3))_(2)^(2-),存在形式受水文地球化学参数pH、Eh以及主成分Cl^(-)、HCO_(3)^(-)影响显著;不同水文期地下水中铀的致癌风险值均未超过规定阈值,对成人和幼儿暂无健康威胁,但仍应加强该区域地下水质量监测,以保障周边环境安全。

Taking a decommissioned uranium mine in south China as an object,the groundwater samples were collected and analyzed from downstream areas of the uranium tailings pond during the wet,norm,and dry seasons,respectively,to find out the temporal and spatial distribution patterns of typical radionuclide uranium in groundwater.The correlation between the different forms of uranium and the environmental parameters of the groundwater was explored.Health risk assessment model was used to classify and evaluate the carcinogenic risks for various populations,which provide a basis for assessing the environmental quality of groundwater following the cessation of mining activities.The results indicate that the average uranium concentration in the groundwater during the wet season downstream of the tailings pond is the highest,reaching 0.14 mg/L.In contrast,during the norm and dry seasons,the uranium content is lower,ranging from 0.017 mg/L to 0.049 mg/L.The primary existing forms of uranium found in the groundwater are UO_(2)(CO_(3))_(4)^(3-)and UO_(2)(CO_(3))_(2)^(2-),which are significantly affected by hydrogeochemical parameters such as pH value,Eh,and major components Cl^(-)and HCO_(3)^(-).Moreover,the carcinogenic risk values of uranium in groundwater do not exceed the specified threshold during different hydrological periods,indicating no health threats to adults and children.Nevertheless,it is crucial to strengthen groundwater quality monitoring in the area to ensure the environmental safety of the surroundings.