北海涠洲岛放射性水平现状调查与评估

目的 对北海涠洲岛地区开展放射性水平调查，全面掌握该地区辐射环境现状，了解天然放射性水平及其分布规律，为科学评价辐射环境质量提供基础资料。方法 依据有关标准与技术规范，于2020年4月—2021年3月对涠洲岛地区开展γ辐射空气吸收剂量率监测和水体、土壤等环境样品中放射性核素浓度采样分析，并结合地域特征对监测结果进行分析探讨。结果 涠洲岛地表γ辐射空气吸收剂量率水平范围为0.2～122 nGy/h；土壤样中²³⁸U、²²⁶Ra、²³²Th、⁴⁰K、¹³⁷Cs活度浓度范围分别为17.0～37.3 Bq/kg、< 0.501～29.5 Bq/kg、< 0.766～54.3 Bq/kg、18.7～369 Bq/kg、< 0.212～1.48 Bq/kg；井水、水库水中U、Th浓度范围为0.065～0.25 μg/L、0.046～0.079 μg/L，²²⁶Ra、⁴⁰K、总α、总β活度浓度范围分别为1.42～3.08 mBq/L、0.069～0.231 Bq/L、0.025～0.163 Bq/L、0.082～0.572 Bq/L；海水中U、Th浓度范围为1.81～2.25 μg/L、0.634～0.648 μg/L，²²⁶Ra、⁴⁰K、⁹⁰Sr、¹³⁷Cs活度浓度范围分别为9.38～19.7 mBq/L、11.3～11.7 Bq/L、0.193～0.866 mBq/L、1.13～1.42 mBq/L。结论 北海涠洲岛地区环境电离辐射水平位于本底涨落范围内，且处于相对较低水平，表明涠洲岛及周围辐射环境质量良好。

Investigation and evaluation of radioactivity level in Weizhou Island of Beihai

Objective The radioactivity level survey was carried out in Weizhou Island area of Beihai, to comprehensively master the radiation environment status in the area, understand the natural radioactivity level and its distribution law, and provide basic data for scientific evaluation of radiation environment quality.Methods According to the relevant standards and technical specifications, the air absorbed dose rate of gamma radiation in Weizhou Island area was monitored from April 2020 to March 2021, the concentrations of radionuclides in water, soil and other environmental samples were sampled and analyzed, and the monitoring results were analyzed and discussed in combination with the regional characteristics.Results The results show that the air absorbed dose rate of gamma radiation in Weizhou Island area ranges from 0.2～122 nGy/h; the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs in solid samples range 17.0～37.3 Bq/kg, < 0.501～29.5 Bq/kg, < 0.766～54.3 Bq/kg, 18.7～369 Bq/kg and < 0.212～1.48 Bq/kg, respectively, the concentrations of U and Th in well water and reservoir water range 0.065～0.25 μg/L, 0.046～0.079 μg/L, the activities of ²²⁶Ra, ⁴⁰K, total α and total β range 1.42～3.08 mBq/L, 0.069～0.231 Bq/L, 0.025～0.163 Bq/L, 0.082～0.572 Bq/L, respectively, the concentrations of U and Th in seawater samples range 1.81～2.25 μg/L, 0.634～0.648 μg/L, and the activities of ²²⁶Ra, ⁴⁰K, ⁹⁰Sr and ¹³⁷Cs range 9.38～19.7 mBq/L, 11.3～11.8 Bq/L、0.193～0.866 mBq/L、1.13～1.42 mBq/L.Conclusion The environmental ionizing radiation level in Weizhou island of Beihai is in the range of background fluctuation and at a relatively low level, indicating that the radiation environmental quality of Weizhou Island and its surrounding areas is good.