某铀尾矿库周边土壤中铀元素的空间分布与污染评价

Spatial Distribution and Pollution Assessment of Uranium in Soil around Uranium Tailings

为查明某铀尾矿库周边土壤中铀元素的空间分布特征及污染程度,对该铀尾矿库进行了现场采样,利用便携式XRF元素分析仪进行了原位测试,并采用SPSS软件对铀元素的测试数据进行了统计分析。结果表明:该铀尾矿库周边土壤中铀元素含量的平均值分别是中国及其所在省土壤中铀元素含量背景值的4倍和2.3倍,而样品中铀元素含量变异系数达到61.84%,属于强变异,且样品中铀元素含量的统计频数属于正偏态分布,这说明该铀尾矿库对其周边土壤产生了一定的污染效应。在统计分析基础上,运用单因子污染指数法与地质累积指数法,并结合Arc GIS空间分析功能对该铀尾矿库周边土壤中铀元素污染程度进行了定量评价,评价结果表明,主要污染区域集中在该铀尾矿库坝址区0~500 m范围内及尾矿库NE侧的应急处理池周围0~100 m内,该评价结果可为铀尾矿库治理及植物修复提供基础数据。

In order to find out the spatial distribution characteristics and pollution levels of uranium in the soils around uranium tailings, portable XRF elemental analyzer was applied to analyze and test in-situ, and SPSS software was used to analyze in-situ test data. The results show that the content of uranium in soil is 4 times and 2.3 times as many as the soil element background values of China and the province of research area. The variable coefficient of the uranium content is 61.84% in soil samples, which shows that contents of uranium are up to standard of strong variation. The frequency statistics of the uranium content in the soil samples is similar to skew normal distribution, which indicates that the soils around the uranium tailings have been polluted to some extent. Based on the results of statistical analysis, single contamination index, geoaccumulation index method and ArcGIS were used to estimate spatial distribution characteristics and pollution level of uranium in the soils around the uranium railings. The pollution assessment results show that the main pollution areas concentrate in the range of 0 m to 500 m around the uranium tailings dam and 0 m to 100 m around the emergency treatment pool in the NE of the uranium tailings. The evaluation results can provide the basic data for carrying out phytoremediation and treating of uranium tailings.