Han Xiaoxiao, Zhu Jianjun, Zhu Yawei, Li Gang, Liu Zhiyong
State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China.
Department of Emergency and Critical Care Medicine, The Second Affiliated Hospital of Soochow University, Suzhou 215006, China.
ACS Omega. 2021 Oct 8;6(41):26897-26909. doi: 10.1021/acsomega.1c03152. eCollection 2021 Oct 19.
During the global nuclear weapon tests, large amounts of radioactive elements are released into the environment. Long-period actinide elements such as Np, Pu, and Am exhibit different behaviors in various environments, and their isotope characteristic fingerprints are of great significance for studying the distribution, migration, and prediction of radioactive pollutants. To investigate the distribution of Am and Np in southern China, activities of Am (0.008 ± 0.012-0.932 ± 0.066 Bq/kg) and Np (0.037 ± 0.003-1.458 ± 0.063 mBq/kg), Np/Pu atom ratios (0.055 ± 0.003-0.864 ± 0.054), and Am/Pu activity ratios (0.033 ± 0.075-15.870 ± 0.477) in 95 surface sediment samples collected from the northern South China Sea and major river basins were analyzed for the first time. Due to the different scavenging mechanisms of Am and Pu, Am is preferentially concentrated by sinking the particulate, while plutonium is scavenged in the coastal area, resulting in a higher Am/Pu activity ratio in estuary and coastal areas. The distribution of Np shows obvious spatial inhomogeneity as the high migration rate. The relevant fingerprint characteristic has changed greatly and needs to be updated urgently. As a result of the convergence of land and sea, Am, Pu, and Np are dominated by terrestrial sediments and deposited in the coastal area of southern China, which should be paid more attention to. This work can establish China's current neptunium radioactivity database, and the difference in Np, Pu, and Am scavenging processes may be a powerful tool for evaluating the impact of the Pearl River Estuary salt tide.
在全球核武器试验期间，大量放射性元素被释放到环境中。钚、镅等长寿命锕系元素在不同环境中表现出不同行为，其同位素特征指纹对于研究放射性污染物的分布、迁移及预测具有重要意义。为研究镅和钚在中国南方的分布情况，首次对采自南海北部和主要流域的95个表层沉积物样品中的镅活度（0.008±0.012 - 0.932±0.066 Bq/kg）、钚活度（0.037±0.003 - 1.458±0.063 mBq/kg）、钚/钚原子比（0.055±0.003 - 0.864±0.054）以及镅/钚活度比（0.033±0.075 - 15.870±0.477）进行了分析。由于镅和钚的清除机制不同，镅优先通过颗粒沉降而富集，而钚在沿海地区被清除，导致河口和沿海地区的镅/钚活度比更高。钚的分布呈现出明显的空间不均匀性，迁移速率较高。相关指纹特征变化很大，急需更新。由于陆海交汇，镅、钚和钚主要由陆源沉积物主导并沉积在中国南方沿海地区，应予以更多关注。这项工作可以建立中国当前的钚放射性数据库，钚、钚和镅清除过程的差异可能是评估珠江口咸潮影响的有力工具。
