The exposure to uranium (U) in the natural environment is primarily through ingestion (eating contaminated food and drinking water) and dermal (skin contact with U powders/wastes) pathways. This study focuses on the dose assessment for different age-groups using the USEPA model. A total of 156 drinking water samples were tested to know U level in the groundwater of the study region. Different age-groups were selected to determine the human health impact due to uranium exposure in the residing populations. To determine the relative importance of each input, a variance decomposition technique, i.e., Sobol sensitivity analysis, was used. Furthermore, different sample sizes were tested to obtain the optimal Sobol sensitivity indices. Three types of effects were evaluated: first-order effect (FOE), second-order effect (SOE) and total effect. The result of analysis revealed that 17% of the samples had U concentration above 30 µg l-1 of U, which is the recommended level by World Health Organization. The mean hazard index (HI) value for younger age-group was found to be less than 1, whereas the 95th percentile value of HI value exceeded for both age-groups. The mean annual effective dose of U for adults was found to be slightly higher than the recommended level of 0.1 m Sv year-1. This result signified that adults experienced relatively higher exposure dose than the children in this region. Sobol sensitivity analysis of FOE showed that the concentration of uranium (Cw) is the most sensitive input followed by intake rate (IR) and exposure frequency. Moreover, the value of SOE revealed that interaction effect of Cw - IR is the most sensitive input parameter for the assessment of oral health risk. On the other hand, dermal model showed Cw - F as the most sensitive interaction input. The larger value of SOE was also recorded for older age-group than for the younger group.

中文翻译：

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Sobol敏感性分析用于地下水中铀的风险评估。

在自然环境中暴露于铀（U）的途径主要是通过摄入（食用受污染的食物和饮用水）和皮肤（与U粉末/废物接触皮肤）途径。这项研究的重点是使用USEPA模型评估不同年龄组的剂量。总共对156个饮用水样品进行了测试，以了解研究区域地下水中的U水平。选择了不同的年龄组来确定居住人口中由于铀暴露对人类健康的影响。为了确定每个输入的相对重要性，使用了方差分解技术，即Sobol灵敏度分析。此外，测试了不同的样本量以获得最佳的Sobol灵敏度指标。评估了三种类型的效应：一阶效应（FOE），二阶效应（SOE）和总效应。分析结果表明，有17％的样品中U的浓度高于30 µg l-1，这是世界卫生组织推荐的水平。发现年轻年龄组的平均危害指数（HI）值小于1，而两个年龄组的HI值的第95个百分位数均超过。发现成年人的U平均年有效剂量略高于建议的0.1 m Sv year-1的推荐水平。该结果表明，该区域的成年人暴露剂量高于儿童。Sobol对FOE的敏感性分析表明，铀（Cw）的浓度是最敏感的输入，其次是摄入率（IR）和暴露频率。此外，SOE的值表明，Cw-IR的相互作用是评估口腔健康风险最敏感的输入参数。另一方面，真皮模型显示Cw-F是最敏感的相互作用输入。与年龄较小的组相比，年龄较大的组的SOE值也更高。