1
|
Igarashi J, Ninomiya K, Zheng J, Zhang Z, Fukuda M, Aono T, Minowa H, Yoshikawa H, Sueki K, Satou Y, Shinohara A. Fukushima Daiichi Nuclear Power Plant Accident: Understanding Formation Mechanism of Radioactive Particles through Sr and Pu Quantities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:14823-14830. [PMID: 39129255 DOI: 10.1021/acs.est.4c03428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
The Fukushima Daiichi Nuclear Power Plant accident released considerable radionuclides into the environment. Radioactive particles, composed mainly of SiO2, emerged as distinctive features, revealing insights into the accident's dynamics. While studies extensively focused on high-volatile radionuclides like Cs, investigations into low-volatile nuclides such as 90Sr and Pu remain limited. Understanding their abundance in radioactive particles is crucial for deciphering the accident's details, including reactor temperatures and injection processes. Here, we aimed to determine 90Sr and Pu amounts in radioactive particles and provide essential data for understanding the formation processes and conditions within the reactor during the accident. We employed radiochemical analysis on nine radioactive particles and determined the amounts of 90Sr and Pu in these particles. 90Sr and Pu quantification in radioactive particles showed that the 90Sr/137Cs radioactivity ratio (corrected to March 11, 2011) aligned with core temperature expectations. However, the 239+240Pu/137Cs activity ratio indicated nonvolatile Pu introduction, possibly through fuel fragments. Analyzing 90Sr and Pu enhances our understanding of the Fukushima Daiichi accident. Deviations in 239+240Pu/137Cs activity ratios underscore nonvolatile processes, emphasizing the accident's complexity. Future research should expand this data set for a more comprehensive understanding of the accident's nuances.
Collapse
Affiliation(s)
- Junya Igarashi
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kazuhiko Ninomiya
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jian Zheng
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
| | - Zijian Zhang
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Miho Fukuda
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
- Research Department, Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu Town, Fukushima 963-7700, Japan
| | - Tatsuo Aono
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
| | - Haruka Minowa
- The Jikei University School of Medicine, 3-25 Nishishinbashi, Minato Ward, Tokyo 105-0003, Japan
| | - Hideki Yoshikawa
- The Jikei University School of Medicine, 3-25 Nishishinbashi, Minato Ward, Tokyo 105-0003, Japan
| | - Keisuke Sueki
- Graduate School of Pure and Material, Tsukuba University, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency, 790-1 Otsuka, Motooka, Tomioka, Futaba, Fukushima 979-1151, Japan
| | - Atsushi Shinohara
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Faculty of Health Science, Osaka Aoyama University, 2-11-1 Niina, Minoh, Osaka 562-8580, Japan
| |
Collapse
|
2
|
Yomogida T, Ouchi K, Morii S, Oka T, Kitatsuji Y, Koma Y, Konno K. Analysis of particles containing alpha emitters in stagnant water in Fukushima Daiichi Nuclear Power Station's Unit 3 reactor building. Sci Rep 2024; 14:14945. [PMID: 38942918 PMCID: PMC11213940 DOI: 10.1038/s41598-024-65522-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/20/2024] [Indexed: 06/30/2024] Open
Abstract
Particles containing alpha (α) nuclides were identified from sediment in stagnant water in the Unit 3 reactor building of the Fukushima Daiichi Nuclear Power Station (FDiNPS). We analyzed different concentrations of α-nuclide samples collected at two sampling sites, the torus room and the main steam isolation valve (MSIV) room. The solids in the stagnant water samples were classified, and the uranium (U) and total alpha concentrations of each fraction were measured by dissolution followed by inductively coupled plasma mass spectrometry and α-spectrometry. Most of the α-nuclides in the stagnant water samples from the torus and MSIV rooms were in particle fractions larger than 10 μm. We detected uranium-bearing particles ranging from sub-µm to 10 µm in size by scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) observations. The chemical forms of U particles were determined in U-Zr oxides, oxidized UO2, and U3O8 with micro-Raman spectroscopy. Other short-lived α-nuclides (plutonium [Pu], americium [Am], and curium [Cm]) were detected by alpha track detection, and the particles with α-nuclides was characterized by SEM-EDX analysis. α-nuclide-containing particles with several tens to several 100 µm in size mainly comprised iron (Fe) oxyhydroxides. In addition, we detected adsorbed U onto Fe oxyhydroxide particles in the MSIV room sample, which indicated nuclear fuel dissolution and secondary U accumulation. This study clarifies the major characteristics of U and other α-nuclides in sediment in stagnant water in the FDiNPS Unit 3 reactor building, which significantly contribute to the consideration of removal methods for particles containing α-nuclides in the stagnant water.
Collapse
Affiliation(s)
- Takumi Yomogida
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan.
| | - Kazuki Ouchi
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Shiori Morii
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Toshitaka Oka
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Yoshihiro Kitatsuji
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan
| | - Yoshikazu Koma
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, Fukushima, 979-1151, Japan
| | - Katsuhiro Konno
- Fukushima Daiichi Decontamination and Decommissioning Engineering Company, Tokyo Electric Power Company Holdings Inc., Fukushima, 979-1301, Japan
| |
Collapse
|
3
|
Ang JWL, Bongrand A, Duval S, Donnard J, Jolis EM, Utsunomiya S, Minomo K, Koivula R, Siitari-Kauppi M, Law GTW. Detecting radioactive particles in complex environmental samples using real-time autoradiography. Sci Rep 2024; 14:5413. [PMID: 38443397 PMCID: PMC10915129 DOI: 10.1038/s41598-024-52876-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
Radioactive particles often contain very high radioactivity concentrations and are widespread. They pose a potential risk to human health and the environment. Their detection, quantification, and characterization are crucial if we are to understand their impact. Here, we present the use of a real-time autoradiography gaseous detector (using parallel ionization multiplier) to expedite and improve the accuracy of radioactive particle screening in complex environmental samples. First, standard particles were used to assess the detector capabilities (spatial resolution, spectrometry, and artefact contributions), then, we applied the technique to more complex and environmentally relevant samples. The real-time autoradiography technique provides data with a spatial resolution (≲100 µm) suitable for particle analysis in complex samples. Further, it can differentiate between particles predominantly emitting alpha and beta radiation. Here, the technique is applied to radioactive cesium-rich microparticles collected from the Fukushima Daiichi nuclear exclusion zone, showing their accurate detection, and demonstrating the viability of real-time autoradiography in environmental scenarios. Indeed, for more complex samples (radioactive particles in a less radioactive heterogeneous background mix of minerals), the technique permits relatively high selectivity for radioactive particle screening (up to 61.2% success rate) with low false positive percentages (~ 1%).
Collapse
Affiliation(s)
- Joyce W L Ang
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
- Singapore Nuclear Safety and Research Initiative, National University of Singapore, Singapore, 138602, Singapore.
| | - Arthur Bongrand
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
- IMT Atlantique, Nantes Université, CNRS, 44000, Nantes, SUBATECH, France
| | - Samuel Duval
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
| | | | - Ester M Jolis
- Circular Economy Solutions Research Laboratory, Geological Survey of Finland GTK, 02151, Espoo, Finland
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Risto Koivula
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Marja Siitari-Kauppi
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Gareth T W Law
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
| |
Collapse
|
4
|
Takaku Y, Higaki S, Hirota M, Kagi H. Radiocesium-bearing microparticles found in dry deposition fallout samples immediately after the Fukushima nuclear accident in the Kanto region, Japan. Sci Rep 2023; 13:21826. [PMID: 38071366 PMCID: PMC10710400 DOI: 10.1038/s41598-023-49158-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
Radiocesium released by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident still exists in the environment in two forms: adsorbed species on mineral particles in the soil and microparticles containing radiocesium mainly composed of silicate glass (CsMPs). CsMPs are dispersed not only around the FDNPP but also over a wide area of the Kanto region. The behavior and characteristics of CsMPs must be investigated to evaluate the impact of the FDNPP accident. Deposited particles including radiocesium were wiped from metal handrails on balconies and car hoods using tissue papers at six locations in the Kanto region (Tokai village, Ushiku City, Abiko City, Chiba City, Kawaguchi City, and Arakawa Ward) between March 15 and 21, 2011. CsMPs were isolated from the samples, and their characteristics were investigated. In total, 106 CsMPs derived from Unit 2 were successfully separated from 13 tissue paper samples. The radiation images of the two types of CsMPs discovered in Ushiku City demonstrate that CsMPs can easily become susceptible to fragmentation over time, even in the absence of weathering effects.
Collapse
Affiliation(s)
- Yuki Takaku
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Shogo Higaki
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
| | - Masahiro Hirota
- Research Center for Supports to Advanced Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Hiroyuki Kagi
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| |
Collapse
|
5
|
Zhao G, Shao Y, Luo M, Xu D, Li D, Liu Z, Ma L. Research progress on the analysis and application of radioactive hot particle. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 270:107313. [PMID: 37857023 DOI: 10.1016/j.jenvrad.2023.107313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Radioactive hot particle is the particulate form of nuclear material that exists in the environment. The U, Pu, Am, Cs, and other radionuclides isotope in the hot particle contain abundant and accurate fingerprint information, such as the origin and age of the nuclear material. The acquisition and analysis of the key information in the hot particle can be equivalent to the analysis of bulk nuclear material, which could directly reflect the real situation of nuclear activities. Therefore, the single particle analysis of hot particles has become an irreplaceable key technology in nuclear safeguards inspection. The rapid identification, screening, locating, and accurate isotope analysis of hot particles from a large number of particles dispersed in environmental media or on the surface of other materials are one of the most important research field in nuclear emergency. In this review, the research process of the analytical methods for hot particles in the last decade was summarized, including the physical character of hot particles, and the techniques of localization, screening, and extraction of hot particles. Furthermore, we also focused on the mass spectrometry technology for the analysis of hot particle. The advantages and disadvantages of the most used mass spectrometry were summarized. Finally, the research trend for hot particle analysis methods was proposed.
Collapse
Affiliation(s)
- Guifang Zhao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yang Shao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Luo
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Diandou Xu
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Duohong Li
- State Nuclear Security Technology Center, Beijing, 102401, China
| | - Zhiming Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lingling Ma
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
| |
Collapse
|
6
|
Higaki S, Yoshida-Ohuchi H, Shinohara N. Radiocesium-bearing microparticles discovered on masks worn during indoor cleaning. Sci Rep 2023; 13:10008. [PMID: 37340042 DOI: 10.1038/s41598-023-37191-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/17/2023] [Indexed: 06/22/2023] Open
Abstract
A decade has passed since the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on March 11, 2011. However, radioactive particles have recently been detected in the indoor air of some residences near the FDNPP. Following the recommendations of previous research, we determined the presence of radiocesium-bearing microparticles (CsMPs) and measured the radioactivity of radiocesium that adhered on non-woven face masks worn by six persons during the indoor cleaning of 59 residences in Namie, Futaba, Okuma, and Tomioka towns in Fukushima Prefecture. Of the 284 masks worn in this study, significant 137Cs radioactivity was detected in 268, and 44 new CsMPs were discovered in 28. The results of this study also suggest the presence of highly concentrated soluble radiocesium particles or soluble radioactive cesium aerosols adhered to house dust. This implies that the CsMPs constituted a large proportion of radioactivity in the indoor air contamination for particles in the 1.0-2.5 µm size range due to the radioactive radiocesium particles. It is desirable to wear masks during cleaning to prevent inhalation of CsMPs.
Collapse
Affiliation(s)
- Shogo Higaki
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
| | | | - Naohide Shinohara
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| |
Collapse
|
7
|
Okumura T, Yamaguchi N, Kogure T. Dissolution behavior of radiocesium-bearing microparticles as a function of solution compositions. Sci Rep 2023; 13:4307. [PMID: 36922544 PMCID: PMC10017807 DOI: 10.1038/s41598-023-31519-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
More than a decade has passed since the Fukushima nuclear accident in 2011 and contamination around the nuclear power plant is primarily caused by 137Cs. One of the materials retaining radiocesium in the environment is radiocesium-bearing silicate glass microparticles (CsMPs), which have not been reported in previous nuclear accidents. Although the prediction of environmental fates of CsMPs is of interest because of their extremely high specific radioactivity, knowledge about their physicochemical properties is still limited. Here we show that the dissolution behavior of CsMPs is comparable to that of silica-rich glass and significantly depends on the surrounding environment. CsMP dissolution experiments were conducted in solutions with various solute components and pH levels at 60 °C. In neutral and basic solutions, the estimated dissolution rate was accelerated by alkali ions such as Na+, which is known to play a catalytic role for the dissolution of silica. In contrast, the dissolution in acid was slow even in the presence of alkali ions. The dissolution under acid conditions was possibly retarded by a thin amorphous silica layer formed on the CsMP surfaces. Such characteristics of the dissolution are consistent with that of silica-rich glass. To infer the dissolution behavior of CsMPs in the human body, the dissolution rate in Ringer's solution at 37 °C was estimated as 1.00 ± 0.37 μm/year.
Collapse
Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-0033, Japan.
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-0033, Japan
| |
Collapse
|
8
|
Suzuki S, Amano Y, Enomoto M, Matsumoto A, Morioka Y, Sakuma K, Tsuruta T, Kaeriyama H, Miura H, Tsumune D, Kamiyama K, Wada T, Takata H. Temporal variability of 137Cs concentrations in coastal sediments off Fukushima. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154670. [PMID: 35314234 DOI: 10.1016/j.scitotenv.2022.154670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Large amounts of radiocesium were released into marine environments following the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Released radiocesium influenced not only marine environment but also marine biota in Fukushima. Since marine biota as fisheries products is important for Japanese market, it is important to assess the distribution of radiocesium in coastal environment off Fukushima for safety concerns of radioactive contamination. Radiocesium concentrations in sediments are important for understanding fishing ground conditions and for proving the safety of fisheries products in Fukushima. In this study, monthly monitoring data collected from May 2011 to March 2020 were analyzed to describe the temporal variability of 137Cs concentrations in coastal sediments off Fukushima (total of 3647 samples from eight lines at depths of 7-125 m off Fukushima, and three sites in Matsukawa-ura Lagoon). The 137Cs concentration in sediment showed a decreasing trend, but our nonlinear model fitting suggested that this rate of decrease had slowed down. Additionally, 137Cs concentrations were up to 4.08 times greater in shallow sampling sites (7, 10, 20 m depth) following heavy rainfall events (before five months vs. after five months), such as typhoons. These observations were consistent with increasing input from particulate 137Cs fluxes from rivers and increasing dissolved 137Cs concentrations in seawater. Finally, our numerical modeling suggested that riverine 137Cs input could maintain 137Cs concentrations in coastal sediment. These results indicate that riverine 137Cs input following heavy rainfall events is the main factor for maintaining 137Cs concentrations in coastal sediments near the Fukushima Daiichi Nuclear Power Plant.
Collapse
Affiliation(s)
- Shotaro Suzuki
- Fukushima Prefectural Fisheries and Marine Science Research Centre, Fukushima, Japan; Fukushima Prefectural Research Institute of Fisheries Resources, Fukushima, Japan.
| | - Yosuke Amano
- Fukushima Prefectural Fisheries and Marine Science Research Centre, Fukushima, Japan
| | - Masahiro Enomoto
- Fukushima Prefectural Fisheries and Marine Science Research Centre, Fukushima, Japan
| | - Akira Matsumoto
- Fukushima Prefectural Research Institute of Fisheries Resources, Fukushima, Japan; Fukushima Prefectural Fishery Office, Fukushima, Japan
| | - Yoshiaki Morioka
- Fukushima Prefectural Research Institute of Fisheries Resources, Fukushima, Japan
| | - Kazuyuki Sakuma
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, Fukushima, Japan
| | - Tadahiko Tsuruta
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, Fukushima, Japan
| | - Hideki Kaeriyama
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Kanagawa, Japan
| | - Hikaru Miura
- Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
| | - Daisuke Tsumune
- Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
| | - Kyoichi Kamiyama
- Fukushima Prefectural Fisheries and Marine Science Research Centre, Fukushima, Japan; Fukushima Prefectural Inland Water Fisheries Experiment Station, Fukushima, Japan
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan
| | - Hyoe Takata
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan
| |
Collapse
|
9
|
Ishii Y, Miura H, Jo J, Tsuji H, Saito R, Koarai K, Hagiwara H, Urushidate T, Nishikiori T, Wada T, Hayashi S, Takahashi Y. Radiocesium-bearing microparticles cause a large variation in 137Cs activity concentration in the aquatic insect Stenopsyche marmorata (Tricoptera: Stenopsychidae) in the Ota River, Fukushima, Japan. PLoS One 2022; 17:e0268629. [PMID: 35594311 PMCID: PMC9122184 DOI: 10.1371/journal.pone.0268629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/03/2022] [Indexed: 11/18/2022] Open
Abstract
After the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Plant accident in Japan, freshwater ecosystems near the site remained contaminated by radiocesium (RCs). Clarifying RCs concentrations in aquatic insects is crucial because fishes consume these insects that transfer RCs into freshwater ecosystems. As aquatic insects are usually measured for radioactivity in bulk samples of several tens of insects, variation in RCs concentration among individuals is not captured. In this study, we investigated the variability in 137Cs activity concentration in individual aquatic insects in detritivorous caddisfly (Stenopsyche marmorata) and carnivorous dobsonfly (Protohermes grandis) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity in 4 of the 46 caddisfly larvae, whereas no such outliers were observed in 45 dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMP distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.
Collapse
Affiliation(s)
- Yumiko Ishii
- Environmental Impact Assessment Section, Fukushima Branch, National Institute for Environmental Studies, Tamura, Fukushima, Japan
- * E-mail: (YI); (HM)
| | - Hikaru Miura
- Meteorology and Fluid Science Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
- * E-mail: (YI); (HM)
| | - Jaeick Jo
- Environmental Impact Assessment Section, Fukushima Branch, National Institute for Environmental Studies, Tamura, Fukushima, Japan
| | - Hideki Tsuji
- Environmental Impact Assessment Section, Fukushima Branch, National Institute for Environmental Studies, Tamura, Fukushima, Japan
| | - Rie Saito
- Fukushima Prefectural Centre for Environmental Creation, Tamura, Fukushima, Japan
| | - Kazuma Koarai
- Japan Atomic Energy Agency, Sector of Fukushima Research and Development, Fukushima, Japan
| | - Hiroki Hagiwara
- Japan Atomic Energy Agency, Sector of Fukushima Research and Development, Fukushima, Japan
| | - Tadayuki Urushidate
- Japan Atomic Energy Agency, Sector of Fukushima Research and Development, Fukushima, Japan
| | - Tatsuhiro Nishikiori
- Agricultural Radiation Research Center, Tohoku Agricultural Research Center, National Agriculture and Food Research Organization, Fukushima-shi, Fukushima, Japan
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan
| | - Seiji Hayashi
- Environmental Impact Assessment Section, Fukushima Branch, National Institute for Environmental Studies, Tamura, Fukushima, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| |
Collapse
|
10
|
Yomogida T, Ouchi K, Oka T, Kitatsuji Y, Koma Y, Konno K. Analysis of particles containing alpha-emitters in stagnant water at torus room of Fukushima Dai-ichi Nuclear Power Station’s Unit 2 reactor. Sci Rep 2022; 12:7191. [PMID: 35577810 PMCID: PMC9110416 DOI: 10.1038/s41598-022-11334-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/20/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractParticles containing alpha (α) nuclides were identified from sediment in stagnant water in the torus room of the Fukushima Dai-ichi Nuclear Power Station(FDiNPS)’s Unit 2 reactor. We analyzed uranium (U), which is the main component of nuclear fuel, using scanning electron microscopy (SEM). Other α-nuclides (plutonium [Pu], americium [Am], and curium [Cm]) were detected by alpha track detection and the morphology of particles with α-nuclides were analyzed by SEM-energy dispersive X-Ray (EDX) analysis. Several uranium-bearing particles ranging from sub-µm to several µm in size were identified by SEM observation. These particles contained zirconium (Zr) and other elements which constituted fuel cladding and structural materials. The 235U/238U isotope ratio in the solid fractions that included U particles was consistent with what was found for the nuclear fuel in the Unit 2 reactor. This indicated that the U of similar fuel composition had made finer. The α-nuclide-containing particles identified by alpha track analysis were several tens to several hundred µm in size. The EDX spectra showed that these particles mainly comprised iron (Fe). Since the amount of α-nuclide material was very small, Pu, Am, and Cm were adsorbed on the Fe particles. This study clarifies that the major morphologies of U and other α-nuclides in the sediment of stagnant water in the torus room of FDiNPS’s Unit 2 reactor differed.
Collapse
|
11
|
Yamamoto T. Activity and weight ratios of cesium, uranium, plutonium, and curium isotopes based on elaborate inventory calculations of Fukushima Dai-ichi NPP units 1 to 3. J NUCL SCI TECHNOL 2022. [DOI: 10.1080/00223131.2022.2051764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
12
|
|
13
|
Hagiwara H, Funaki H, Shiribiki N, Kanno M, Sanada Y. Characterization of radiocesium-bearing microparticles with different morphologies in soil around the Fukushima Daiichi nuclear power plant. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-021-08061-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
14
|
Kasar S, Mishra S, Sahoo SK, Kavasi N, Omori Y, Arae H, Sorimachi A, Aono T. Sorption-desorption coefficients of uranium in contaminated soils collected around Fukushima Daiichi Nuclear Power Station. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 233:106617. [PMID: 33866199 DOI: 10.1016/j.jenvrad.2021.106617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/08/2021] [Accepted: 04/06/2021] [Indexed: 06/12/2023]
Abstract
Various radionuclides including fission products and heavy nuclides were released into the environment during the Fukushima Daiichi Nuclear Power Station (FDNPS) accident. The dissolution followed by migration of deposited radionuclides of Cs, Sr and U on soils could take place to the local environment. Therefore, it is necessary to determine sorption-desorption coefficients of U in soil-water system around the FDNPS from a migration viewpoint. The determination of sorption coefficient Kd(S) as well as desorption coefficient Kd(D) for U has been carried out in the present study using a laboratory batch method. Stable U was used for sorption from simulated ground water onto contaminated soil samples collected from Okuma Town, Fukushima. Different soil parameters were measured to understand their effects on sorption and desorption processes. The obtained Kd(S) and Kd(D) values of U were compared with values of Kd(S) and Kd(D) of Cs and Sr and Kd(S)-U in known Fukushima accident contaminated soils reported in the literature for better understanding. It was observed that Kd(S)-U varied from 160 to 5100 L/kg, whereas Kd(D)-U ranged from 200 to 11000 L/kg. Kd(D) was higher than Kd(S) for U in these soils implying irreversibility of the sorption process. Pearson's correlation of Kd(S) values suggested that U sorption is affected by various soil parameters. However, desorption is decided by the nature of U species formed in sorption process and soil parameters like pH, presence of carbonates, Ca ions, clay minerals etc. to some extent. The comparison between Kd(S) and Kd(D) values for Cs, Sr and U revealed that unsorbed Sr could migrate farther than unsorbed Cs or U under the present experimental conditions. Both sorption and desorption studies are of great importance to understand migration of metal ions from contaminated sites to local uncontaminated areas.
Collapse
Affiliation(s)
- S Kasar
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan
| | - S Mishra
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan; Environmental Monitoring and Assessment Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - S K Sahoo
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan.
| | - N Kavasi
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan
| | - Y Omori
- Department of Radiation Physics and Chemistry, Fukushima Medical University, 1, Hikarigaoka, Fukushima 960-1295, Japan
| | - H Arae
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan
| | - A Sorimachi
- Integrated Center for Science and Humanities, Fukushima Medical University, 1, Hikarigaoka, Fukushima 960-1295, Japan
| | - T Aono
- Environmental Radionuclides Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1Anagawa, Chiba, 263-8555, Japan
| |
Collapse
|
15
|
Miura H, Ishimaru T, Ito Y, Kurihara Y, Otosaka S, Sakaguchi A, Misumi K, Tsumune D, Kubo A, Higaki S, Kanda J, Takahashi Y. First isolation and analysis of caesium-bearing microparticles from marine samples in the Pacific coastal area near Fukushima Prefecture. Sci Rep 2021; 11:5664. [PMID: 33707572 PMCID: PMC7952385 DOI: 10.1038/s41598-021-85085-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/19/2021] [Indexed: 11/22/2022] Open
Abstract
A part of the radiocaesium from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident was emitted as glassy, water-resistant caesium-bearing microparticles (CsMPs). Here, we isolated and investigated seven CsMPs from marine particulate matter and sediment. From the elemental composition, the 134Cs/137Cs activity ratio, and the 137Cs activity per unit volume results, we inferred that the five CsMPs collected from particulate matter were emitted from Unit 2 of the FDNPP, whereas the two CsMPs collected from marine sediment were possibly emitted from Unit 3, as suggested by (i) the presence of calcium and absence of zinc and (ii) the direction of the atmospheric plume during the radionuclide emission event from Unit 3. The presence of CsMPs can cause overestimation of the solid-water distribution coefficient of Cs in marine sediments and particulate matter and a high apparent radiocaesium concentration factor for marine biota. CsMPs emitted from Unit 2, which were collected from the estuary of a river that flowed through a highly contaminated area, may have been deposited on land and then transported by the river. By contrast, CsMPs emitted from Unit 3 were possibly transported eastward by the wind and deposited directly onto the ocean surface.
Collapse
Affiliation(s)
- Hikaru Miura
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan.
| | - Takashi Ishimaru
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yukari Ito
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yuichi Kurihara
- Ningyo-Toge Environmental Engineering Centre, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama, 708-0698, Japan
| | - Shigeyoshi Otosaka
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8564, Japan
| | - Aya Sakaguchi
- Centre for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Kazuhiro Misumi
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan
| | - Daisuke Tsumune
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan
| | - Atsushi Kubo
- Department of Geosciences, Faculty of Science College of Science, Academic Institute, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Shogo Higaki
- Isotope Science Centre, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Jota Kanda
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| |
Collapse
|
16
|
Kubo A, Tanabe K, Ito Y, Ishimaru T, Otsuki M, Arakawa H, Watanabe YW, Miura H, Tsumune D, Kanda J. Changes in radioactive cesium concentrations from 2011 to 2017 in Fukushima coastal sediments and relative contributions of radioactive cesium-bearing microparticles. MARINE POLLUTION BULLETIN 2020; 161:111769. [PMID: 33091633 DOI: 10.1016/j.marpolbul.2020.111769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 06/11/2023]
Abstract
Sedimentary cesium-137 concentrations around the Fukushima Daiichi Nuclear Power Plant (FDNPP) were measured from 2011 to 2017 at eight stations. Although high values were observed until 2013, decreasing trends were observed at the surface sediments of seven stations. We isolated 25 radioactive Cs-bearing microparticles (CsMPs; 1.0-5385 Bq per particle). The contribution ratio of CsMPs to each sample ranged from 4.1% to 99.5% (median 58.8%), with the contribution ratio of the CsMPs in the southern part of the FDNPP was low compared to that from the northern part. In the southern part of the FDNPP, small CsMPs that could not be isolated in this study were present in large quantities immediately after the accident, and gradually diffused away and/or were dissolved over time. In contrast, the CsMPs in the northern part of the FDNPP have most likely accumulated over time, as suggested by the silty nature of the sediments there.
Collapse
Affiliation(s)
- Atsushi Kubo
- Department of Geosciences, Shizuoka University, Shizuoka, Japan; Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan.
| | - Kai Tanabe
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Yukari Ito
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Takashi Ishimaru
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Mayumi Otsuki
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Hisayuki Arakawa
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Yutaka W Watanabe
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Hikaru Miura
- Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
| | - Daisuke Tsumune
- Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
| | - Jota Kanda
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan
| |
Collapse
|
17
|
Futagami F, Soliman M, Takamiya K, Sekimoto S, Oki Y, Kubota T, Konno M, Mizuno S, Ohtsuki T. Isolation, characterization and source analysis of radiocaesium micro-particles in soil sample collected from vicinity of Fukushima Dai-ichi nuclear power plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 223-224:106388. [PMID: 32868095 DOI: 10.1016/j.jenvrad.2020.106388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/23/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
Radioactive caesium was released during the accident of Fukushima Dai-ichi nuclear power plant (FDNPP) into the surrounding environment. In the current work, radiocaesium micro-particles (CsMPs) and radiocaesium-rich soil particles were selectively separated from soil particles as well as from each other using autoradiography-based procedure. The applied separation scheme is based on water dilution followed by drying of the soil sample prior to imaging plate autoradiography. The SEM/EDS investigation of the individual CsMPs showed that these particles have a silicate glass structure and vary in shape with a diameter less than 10 μm. For the first time, a two-stage formation mechanism was suggested for a CsMP based on shape and structure heterogeneity of its two parts. Perfect spherical core might be formed in the first stage with a remarkable lower content of Al, and relatively higher concentrations of Si and K than an outer angulated structure, which might be attached to the core sphere during a late stage. The radiocaesium-rich soil particles have bigger size than CsMPs and have a plate-like structure with cleavages inside the grains, which suggest that these particles might be a weathered biotite. The average radioactivity ratio of 134Cs/137Cs (dated March 11, 2011) in the investigated particles was found to be 1.05 ± 0.01, which confirmed that the radiocaesium in CsMPs and in the contaminated soil particles has the same source of origin, which could be unite 3 of FDNPP.
Collapse
Affiliation(s)
- Fumiya Futagami
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Mohamed Soliman
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan; Egypt Second Research Reactor, Egyptian Atomic Energy Authority, Cairo, Egypt.
| | - Koichi Takamiya
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Shun Sekimoto
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Yuichi Oki
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Takumi Kubota
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Mitsuyuki Konno
- Citizens and Environmental Affairs Department, Ken-poku Development Bureau, Fukushima Prefecture Government, Japan
| | - Satoshi Mizuno
- Nuclear Power Safety Division, Fukushima Prefecture Government, Japan
| | - Tsutomu Ohtsuki
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| |
Collapse
|
18
|
Miura H, Kurihara Y, Yamamoto M, Sakaguchi A, Yamaguchi N, Sekizawa O, Nitta K, Higaki S, Tsumune D, Itai T, Takahashi Y. Characterization of two types of cesium-bearing microparticles emitted from the Fukushima accident via multiple synchrotron radiation analyses. Sci Rep 2020; 10:11421. [PMID: 32694627 PMCID: PMC7374699 DOI: 10.1038/s41598-020-68318-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/22/2020] [Indexed: 12/05/2022] Open
Abstract
A part of radiocesium emitted during the Fukushima nuclear accident was incorporated in glassy water-resistant microparticles, called Type-A particles, which are spherical with ~ 0.1 to 10 µm diameter and ~ 10-2 to 102 Bq cesium-137 (137Cs) radioactivity; they were emitted from Unit 2 or 3 of the Fukushima Daiichi Nuclear Power Plant. Meanwhile, Type-B particles, having various shapes, 50-400 µm diameter, and 101-104 Bq 137Cs radioactivity, were emitted from Unit 1. The chemical properties of these radioactive particles have been reported in detail, but previous studies investigated only a small number of particles, especially Type-B particles. We tried to understand radioactive particles systematically by analyzing a large number of particles. Micro-X-ray computed tomography combined with X-ray fluorescence analysis revealed the presence of many voids and iron-rich part within Type-B particles. The 137Cs concentration (Bq mm-3) of Type-A particles was ~ 10,000 times higher than that of Type-B particles. Among the Type-B particles, the spherical ones had higher concentration of volatile elements than the non-spherical ones. These differences suggested that Type-A particles were formed through gas condensation, whereas Type-B particles were formed through melt solidification. These findings might contribute to the safe decommissioning of reactors and environmental impact assessment.
Collapse
Affiliation(s)
- Hikaru Miura
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba, 270-1194, Japan.
| | - Yuichi Kurihara
- Ningyo-Toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama, 708-0698, Japan
| | - Masayoshi Yamamoto
- Low Level Radioactivity Laboratory, Kanazawa University, Kanazawa, Ishikawa, 923-1224, Japan
| | - Aya Sakaguchi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3, Kannondai, Tsukuba, Ibaraki, 305-8604, Japan
| | - Oki Sekizawa
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kiyofumi Nitta
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Shogo Higaki
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Daisuke Tsumune
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba, 270-1194, Japan
| | - Takaaki Itai
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| |
Collapse
|