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Yamada R, Hasegawa H, Akata N, Kakiuchi H, Ochiai S, Kuwata H, Kheamsiri K, Tokonami S, Ueda S. Temporal variation of tritium concentration in monthly precipitation collected at a Difficult-to-Return Zone in Namie Town, Fukushima Prefecture, Japan. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:7818-7827. [PMID: 38170359 DOI: 10.1007/s11356-023-31652-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/17/2023] [Indexed: 01/05/2024]
Abstract
This article discusses tritium concentrations in monthly precipitation in part of the Difficult-to-Return Zone in Namie Town during 2012-2021. The tritium concentrations, which were measured with a low background liquid scintillation counter after carrying out an enrichment procedure, fluctuated seasonally from 0.10 ± 0.02 to 0.85 ± 0.02 Bq L-1. This range of concentrations is concluded to not be unusual based on comparisons with the concentrations at other sites and estimates of the past range of the concentrations. Moreover, no significant variations in observed tritium concentrations were observed due to decommissioning work at the Fukushima Dai-ichi Nuclear Power Plant. These results contribute to understanding the background level of tritium concentration in precipitation before the oceanic discharge of treated water from the Fukushima plant. In addition, this article evaluates the amount of tritium supplied to the ocean by terrestrial rainwater pouring into the Pacific Ocean via Ukedo River, which flows through Namie Town; this information will contribute to the discussion on the impact of the oceanic discharge of treated water.
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Affiliation(s)
- Ryohei Yamada
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan
| | - Hidenao Hasegawa
- Department of Radioecology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Kamikita, Aomori, 039-3212, Japan
| | - Naofumi Akata
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan.
| | - Hideki Kakiuchi
- Department of Radioecology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Kamikita, Aomori, 039-3212, Japan
| | - Shinya Ochiai
- Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, O24 Wake, Nomi, Ishikawa, 923-1224, Japan
| | - Haruka Kuwata
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan
- Hirosaki University Graduate School of Health Science, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan
| | - Khemruthai Kheamsiri
- Hirosaki University Graduate School of Health Science, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-Cho, Hirosaki, Aomori, 036-8564, Japan
| | - Shinji Ueda
- Department of Radioecology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Kamikita, Aomori, 039-3212, Japan
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Monthly Precipitation Collected at Hirosaki, Japan: Its Tritium Concentration and Chemical and Stable Isotope Compositions. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Monthly precipitation samples were collected at Hirosaki, Aomori Prefecture from January 2018 to December 2020 to measure the ion species and stable hydrogen and oxygen isotope ratios in order to understand the regional properties. The tritium concentration ranged from 0.28 to 1.20 Bq/L, with mean values (±S.D.) of 0.52 ± 0.18, 0.67 ± 0.25 and 0.63 ± 0.21 Bq/L in 2018, 2019 and 2020, respectively. This concentration level was almost the same as for Rokkasho, Aomori Prefecture. The tritium concentration had clear seasonal variation: high in the spring and low in the summer. This trend was thought to arise from seasonal fluctuations in the atmospheric circulation. On the other hand, the pH tended to be low, and the electrical conductivity (EC) tended to be high from the winter to the spring. The ion components, which major ion species contained in sea salt, also tended to be high in the winter, and these components had a strong influence on EC. The d-excess values were high in the winter and low in the summer, and when this trend was considered from the viewpoint of the wind direction data in Hirosaki, these dust components were attributed to the northwest monsoon in the winter to the spring coming from the Asian continent.
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Akata N, Kakiuchi H, Tanaka M, Ishikawa Y, Kurita N, Furukawa M, Hegedűs M, Kovács T, Gusyev M, Sanada T. Isotope and chemical composition of monthly precipitation collected at Sapporo, northern part of Japan during 2015-2019. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Akata N, Tanaka M, Iwata C, Kato A, Nakada M, Kovács T, Kakiuchi H. Isotope Composition and Chemical Species of Monthly Precipitation Collected at the Site of a Fusion Test Facility in Japan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16203883. [PMID: 31614963 PMCID: PMC6843846 DOI: 10.3390/ijerph16203883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 11/16/2022]
Abstract
The deuterium plasma experiment was started using the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and the hydrogen isotope effects towards the realization of fusion energy. In order to clarify any experimental impacts on precipitation, precipitation has been collected at the NIFS site since November 2013 as a means to assess the relationship between isotope composition and chemical species in precipitation containing tritium. The tritium concentration ranged from 0.10 to 0.61 Bq L-1 and was high in spring and low in summer. The stable isotope composition and the chemical species were unchanged before and after the deuterium plasma experiment. Additionally, the tritium concentration after starting the deuterium plasma experiment was within three sigma of the average tritium concentration before the deuterium plasma experiment. These results suggested that there was no impact by tritium on the environment surrounding the fusion test facility.
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Affiliation(s)
- Naofumi Akata
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki 036-8564, Japan.
| | - Masahiro Tanaka
- Department of Helical Plasma Research, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Chie Iwata
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Akemi Kato
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Miki Nakada
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology, University of Pannonia, H-820010 Egyetem Str, Veszprém, Hungary.
| | - Hideki Kakiuchi
- Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212, Japan.
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