中国土壤和湖泊沉积物中钚同位素分布特征和应用研究

Distribution characteristics and application of Pu isotopes in soils and lake sediments of China

钚(Pu)是与核工业密切相关的、以痕量或超痕量存在于环境中的重要放射性核素。综述了近年来中国土壤和湖泊沉积物中^(239+240)Pu的分布特征、迁移行为及其在环境地球化学中的应用。结果显示:中国土壤和湖泊沉积物中^(239+240)Pu沉降通量分别为7.31~554.00和4.80~240.60 MBq/km^(2),因研究区域所处环境及纬度的差异而变化;^(240)Pu/^(239)Pu同位素比值分别为0.048~0.307和0.164~0.193,平均值分别为0.181±0.026和0.179±0.021;全球大气核试验沉降是中国土壤和湖泊沉积物中^(239+240)Pu的主要来源。作为重要的长寿命放射性核素,在今后的研究中应加强Pu同位素与其他放射性核素示踪技术(^(137)Cs、^(210)Pb和^(7)Be示踪法等)、遥感技术以及传统研究方法相结合,有利于提升大尺度环境区域中Pu的分析精度,提高^(239+240)Pu放射性核素示踪技术的示踪效率。

Plutonium(Pu)is an important radionuclide that exists in the environment in trace or ultra-trace level,which is closely associated with the nuclear industry.The distribution characteristics,migration behavior and the application in geochemistry of^(239+240)Pu in soil and lake sediments in recent years in China were reviewed.The results showed that the sedimentation fluxes of^(239+240)Pu in soils were estimated at from 7.31 MBq/km^(2)to 554.00 MBq/km^(2);while that of^(239+240)Pu in lake sediments were from 4.80 MBq/km^(2)to 240.60 MBq/km^(2),varying with the environment and latitude in the study area.^(240)Pu/^(239)Pu isotope ratios from soils and lake sediments were found to be within 0.048-0.307 and 0.164-0.193,with an average of 0.181±0.026 and 0.179±0.021,respectively.Global atmospheric nuclear test sedimentation was the main source of^(239+240)Pu in China.As an important long-lived radionuclide,the combination of Pu isotope with other radionuclide tracing methods(e.g.137Cs,210Pb and 7Be tracing methods),remote sensing technology and traditional research methods should be strengthened in future research,which was conducive to improving the analysis accuracy of Pu in large-scale environmental areas and the tracing efficiency of^(239+240)Pu radionuclide tracing technology.