Reconstruction of uranium and plutonium isotopic signatures in sediment accumulated in the Mano Dam reservoir, Japan, before and after the Fukushima nuclear accident. (June 2019)

• Record Type: Journal Article
• Authors: Jaegler, Hugo; Pointurier, Fabien; Diez-Fernández, Silvia; Gourgiotis, Alkiviadis; Isnard, Hélène; Hayashi, Seiji; Tsuji, Hideki; Onda, Yuichi; Hubert, Amélie; Laceby, J. Patrick; Evrard, Olivier
• Is Part Of: Chemosphere. Volume 225(2019)
• Page Start: 849
• Page End: 858
• Publication Date: 2019-06
• Subjects: Japanese FDNPP accident -- Mano dam sediment core -- Paddy field soil -- MC-ICP-MS and ICP-MS/MS -- U and Pu isotope ratios -- Source apportionment; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.03.064
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in Japan resulted in a major release of radionuclides into the environment. Compared to other radionuclides, few studies have investigated the fate of actinides in the environment. Accordingly, this research investigates the Pu composition in soil samples collected in paddy fields before and after the accident. Furthermore, the vertical distributions of Pu and U isotopic signatures, along with 137 Cs activities, were measured in a sediment core collected in the Mano Dam reservoir, in the Fukushima Prefecture. Changes in the relative contributions of the major actinide sources (global fallout or FDNPP derived fallout) were investigated in sediment deposited in the reservoir. The distinct peak observed for all Pu isotope ratios ( 240 Pu/ 239 Pu, 241 Pu/ 239 Pu and 242 Pu/ 239 Pu) and for 137 Cs concentrations in the sediment core was attributed to the Fukushima fallout, and coincided with the maximum atomic contribution of only 4.8 ± 1.0% of Pu from the FDNPP. Furthermore, 236 U/ 238 U ratios measured in the sediment core remained close to the global fallout signature indicating there was likely no U from the FDNPP accident detected in the sediment core. More research is required on the environmental dynamics of trace actinides in landscapes closer to the FDNPP where there are likely to be greater abundances of FDNPP-derived Pu and U. Graphical abstract: Image 1 Highlights: Measurement of U and Pu isotopes at ultra-trace levels in a sediment core by ICP-MS. Pu in the sediment is a mix of global fallout and FDNPP-derived fallout sources. Although detectable, the release of Pu from the FDNPP remained low in the sediment. No FDNPP-derived U detected in the sediment core.