鄂尔多斯盆地西南缘某煤田放射性地质环境调查评价

Radioactive geological environment investigation and evaluation of a coal field on southwest edge of Ordos Basin

  • 摘要: 放射性元素兼具化学毒性和放射性。煤炭资源在开发和利用过程中,煤层中可能赋存的放射性元素经过迁移、衰变、扩散等过程,会对矿区及周围的地质环境造成辐射污染,进而影响人居健康,因此有必要根据实际调研情况,对某些可能存在辐射污染的煤田开展放射性地质环境调查评价。项目实施过程中,在鄂尔多斯盆地西南缘某煤田多个勘查钻孔中发现含煤岩系存在放射性异常,由此推测该煤田在开采过程中可能存在放射性辐射污染。为进一步查明该煤田开采过程中放射性核素对地质环境的影响,文章运用环境地表γ辐射剂量率测量、氡浓度测定及样品测试等技术手段,对研究区开展了放射性地质环境调查与评价。γ辐射剂量率和氡浓度测量分析表明,研究区煤矿开采整体上对矿区及周边放射性地质环境影响不大,属豁免监管类。同时结合样品测试分析结果,对研究区主要环境影响因子进行了放射性评价。评价结果显示:煤炭开发利用产生的煤渣煤灰等废弃物存在潜在的放射性污染,不可作为建筑物主体材料和A,B类装饰装修材料,仅可作为C类装饰装修材料,用于建筑物的外饰面和室外其他用处材料;煤田及周边土壤放射性污染为可接受水平,煤矿开采对周边土壤及底泥放射性环境影响不大,对居民放射性危害处于安全范围内;煤田开发过程中所排放的废水对区域地表水和地下水不存在放射性污染,但水体不能直接作为生活饮用水水源。

     

    Abstract: Radioactive elements exhibit both chemical toxicity and radioactivity. During the development and utilization of coal resources, radioactive elements that may exist in coal seams can cause radiation pollution to the geological environment of the mining area and its surroundings through processes such as migration, decay, and diffusion, thereby impacting human health. Therefore, it is necessary to conduct investigations and evaluations of the radioactive geological environment in certain coal fields that may be subject to radiation pollution, based on actual research findings. During the project implementation, radioactive anomalies were discovered in multiple exploration boreholes within a coal-bearing rock series located on the southwestern edge of the Ordos Basin. This suggests that there may have been radioactive radiation pollution during the mining process in this coal field. To further clarify the impact of radionuclides on the geological environment during coal mining, techniques such as measurements of environmental terrestrial gamma radiation dose rates, radon concentration assessments, and sample testing were employed to conduct an investigation and evaluation of the radioactive geological environment in the study area. The analysis of gamma radiation dose rates and radon concentrations indicates that coal mining in the study area has minimal overall impact on the radioactive geological environment of the mining area and its surroundings, falling within the category of exemption from supervision. Additionally, based on the results of sample testing, a radioactive evaluation of the main environmental impact factors in the study area was conducted. The evaluation results reveal that waste generated from coal development and utilization, such as coal ash and slag, poses potential radioactive pollution and cannot be used as primary building materials or as Class A and B decorative materials. It can only be used as Class C decorative materials for building exteriors and other outdoor applications. The levels of radioactive pollution in the coalfield and surrounding soil are considered acceptable. Coal mining has little impact on the radioactive environment of the surrounding soil and sediment, and the radioactive hazard to residents is within a safe range. Furthermore, the wastewater discharged during coal field development shows no radioactive pollution to regional surface water and groundwater; however, this water should not be directly used as a drinking water source.

     

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