Abstract:

Soil is one of the main sources of radionuclide transfer to the environment. Using a GC6020 high-purity germanium γ spectrometer, we investigated γ-emitting nuclides in soil samples from 2017 to 2022 in 14 districts in Hubei Province. Five γ-emitting nuclides (¹³⁷Cs, ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K) were analyzed. We analyzed the massic activity and distribution patterns of these nuclides and estimated the equivalent Ra activity, external exposure index, γ-radiation dose rate, annual effective dose rate, and lifetime of cancer risk. The average massic activities of ⁴⁰K, ¹³⁷Cs, ²²⁶Ra, ²³²Th, and ²³⁸U in the 84 samples were 567, 1.04, 30.3, 47.1, and 39.6 Bq∙kg⁻¹ (dry), respectively. The correlation between the ¹³⁷Cs and ⁴⁰K activity concentrations in the soil was analyzed. The average calculated equivalent Ra activity was 141 Bq∙kg⁻¹. The average external exposure index was 0.38. The average dose rate of γ radiation was 65.9 nGy∙h⁻¹. The average annual effective dose rate was 80.9 μSv∙a⁻¹. The average lifetime cancer risk was 0.32×10⁻³. The radiation dose rate calculated by radionuclide massic activity in soil was compared with the data measured by atmospheric radiation automatic monitoring stations in Hubei Province in 2022, which verified the reliability of radionuclide measurements in soil.

Key words: Hubei, soil, nuclides, dose, distribution, radioactivity, risk

摘要：

土壤是放射性核素向环境转移的主要辐射源之一。用GC6020高纯锗γ能谱仪对2017－2022年湖北省14个地区土壤中的γ放射性核素进行了调查，选取土壤中的5种核素（¹³⁷Cs、²³⁸U、²³²Th、²²⁶Ra和⁴⁰K）作为研究对象，分析核素的质量活度和分布规律，估算等效镭比活度、外照射指数、γ辐射剂量当量率、年有效剂量当量率和终生癌症风险。84份样品中⁴⁰K、¹³⁷Cs、²²⁶Ra、²³²Th和²³⁸U的质量活度平均值分别为567、1.04、30.3、47.1和39.6 Bq∙kg⁻¹（以干物计）。对土壤中¹³⁷Cs和⁴⁰K质量活度的相关性进行了详细分析。经计算，等效镭比活度平均值为141 Bq∙kg⁻¹，外照射指数平均值为0.38，γ辐射剂量当量率平均值为65.9 nGy∙h⁻¹，年有效剂量当量率平均值为80.9 μSv∙a⁻¹，终生癌症风险平均值为0.32×10⁻³。将土壤中放射性核素质量活度计算得出的γ辐射剂量当量率与2022年湖北省大气辐射自动监测站测量的数据进行比较，验证了研究土壤中放射性核素测量的可靠性。

关键词: 湖北, 土壤, 核素, 剂量, 分布, 放射性, 风险