某水源水总α放射性水平调查与评价

Investigation and evaluation of the total α level in a groundwater source

目的对某区部分点位总α浓度较高的饮用水源水进行核素分析和内照射剂量估算,并提出合理解释和可能的解决方案。方法总α浓度及核素分析参照现行国内相关标准进行测量,摄入的内照射剂量估算参照国际通行的公式。结果基于总α的测量结果,长期饮用该水源地生水的居民,其内照射年有效剂量均值为0.09 mSv/a,最大值有可能超过饮用水剂量指导水平(0.1 mSv/a);饮用水中总α放射性主要是由U和226Ra贡献的,内照射剂量U占小部分,主要来源于^226Ra,但未超过WHO关于饮用水所致辐射的健康效应有关放射性核素浓度的指导水平。结论该地区地下水总α放射性偏高的原因可能与该地区的地质结构有关。地下水在其形成过程中,溶入了围岩中的天然放射性核素,最终导致结果偏高。

Objective To analyze the radionuclides contents and estimate the internal dose for the raw water with a high level of totalαactivity in some sites of a region,and to provide the reasonable explanations and possible solutions.Methods The totalαactivity concentration and radionuclide analysis were determined according to the current domestic relevant standards.The international formula was used for the internal irradiation dose estimation.Results Based on the measured totalαlevel,the average annual effective dose of internal irradiation for residents who have been drinking the raw water in this area for long time was averaged to be 0.09 mSv and the maximum dose might exceed the recommended drinking water dose level(0.1 mSv/a).The totalαactivity in the drinking water was mainly contributed by U and ^226Ra,and the internal radiation dose came mainly from ^226Ra.However,the ^226Ra content in the drinking water did not exceed the guidance level recommended by WHO.Conclusion The high radioactivity level of totalαin the groundwater in this area may be related to the geological structure of the area.The natural radioactive nuclides in the aquifer rock may dissolve into and are concentrated during the formation of groundwater,which eventually result in the high totalαlevel in the groundwater.