School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK.
Bristol Isotope Group, University of Bristol, Wills Memorial Building, Queen's Road, Bristol, BS8 1RJ, UK.
Sci Rep. 2018 Nov 14;8(1):16799. doi: 10.1038/s41598-018-34302-0.
Plutonium and radiocaesium are hazardous contaminants released by the Fukushima Daiichi nuclear power plant (FDNPP) disaster and their distribution in the environment requires careful characterisation using isotopic information. Comprehensive spatial survey of Cs and Cs has been conducted on a regular basis since the accident, but the dataset for Cs/Cs atom ratios and trace isotopic analysis of Pu remains limited because of analytical challenges. We have developed a combined chemical procedure to separate Pu and Cs for isotopic analysis of environmental samples from contaminated catchments. Ultra-trace analyses reveal a FDNPP Pu signature in environmental samples, some from further afield than previously reported. For two samples, we attribute the dominant source of Pu to Reactor Unit 3. We review the mechanisms responsible for an emergent spatial pattern in Cs/Cs in areas northwest (high Cs/Cs, low Cs/Cs) and southwest (low Cs/Cs, high Cs/Cs) of FDNPP. Several samples exhibit consistent Cs/Cs values that are significantly different from those deposited on plant specimens collected in previous works. A complex spatial pattern of Pu and Cs isotopic signature is apparent. To confidently attribute the sources of mixed fallout material, future studies must focus on analysis of individual FDNPP-derived particles.
钚和放射性铯是福岛第一核电站（FDNPP）灾难释放的危险污染物，其在环境中的分布需要利用同位素信息进行仔细的特征描述。自事故发生以来，一直在定期对 Cs 和 Cs 进行全面的空间调查，但由于分析上的挑战，Pu 的 Cs/Cs 原子比和痕量同位素分析数据集仍然有限。我们开发了一种组合化学程序，用于分离 Pu 和 Cs，以便对受污染集水区的环境样本进行同位素分析。超痕量分析显示，环境样本中存在 FDNPP Pu 特征，其中一些样本的来源比之前报道的更远。对于两个样本，我们将 Pu 的主要来源归因于 3 号反应堆单元。我们回顾了导致 FDNPP 西北（高 Cs/Cs，低 Cs/Cs）和西南（低 Cs/Cs，高 Cs/Cs）地区 Cs/Cs 出现新的空间分布模式的机制。一些样本的 Cs/Cs 值与以前在植物标本上收集到的值明显不同。Pu 和 Cs 同位素特征的复杂空间模式是明显的。为了有信心地确定混合沉降物质的来源，未来的研究必须集中于分析单个 FDNPP 衍生颗粒。
