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Niang M, Kalinowski M, Christoudias T, Bamba Dath CA, Niane A, Boye Faye NA. Radioactivity of the atmospheric aerosols detected by CTBTO stations in Africa following the accident at the Fukushima Daiichi nuclear power plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 276:107439. [PMID: 38692068 DOI: 10.1016/j.jenvrad.2024.107439] [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: 01/21/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024]
Abstract
Radionuclides from the reactor accident Fukushima Daiichi nuclear power plant were observed in the airborne aerosols at CTBT International Monitoring System (IMS) stations (MRP43, CMP13) in Africa. The maximum activity concentrations in the air measured in Mauritania were 186.44 10-6 Bq.m-3, 264.16 10-6 Bq.m-3 and 1269.94 10-6 Bq.m-3 for 134Cs, 137Cs and 131I respectively, and in Cameroon 16.42 10-6 Bq.m-3, 25.53 10-6 and 37.58 10-6 Bq.m-3 respectively for 134Cs, 137Cs and 131I. The activity ratio of 134Cs/137Cs is almost constant throughout the period of time relevant to this study due to their long half-lives of 30.2 years for 137Cs and 2.06 years for 134Cs. Whereas the 131I/137Cs activity ratio varies in time according to the radioactive decay with a half-live of 8.06 days for 131I and different removal rates of both radionuclides from the atmosphere during transport. The EMAC atmospheric chemistry-general circulation was used to simulate the emission and transport of the isotope 137Cs and map the deposition of the 137Cs deposition over Africa.
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Affiliation(s)
- Modou Niang
- Laboratory of Atoms Lasers, Department of Physics, Faculty of Sciences and Techniques, University Cheikh Anta Diop, Dakar, 5005, Senegal; Senegalese Nuclear Safety and Security Regulatory Authority, Senegal.
| | - Martin Kalinowski
- Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission, PO Box 1200, 1400, Vienna, Austria
| | | | - Cheikh Amadou Bamba Dath
- Laboratory of Atoms Lasers, Department of Physics, Faculty of Sciences and Techniques, University Cheikh Anta Diop, Dakar, 5005, Senegal; Senegalese Nuclear Safety and Security Regulatory Authority, Senegal
| | - Aliou Niane
- Laboratory of Atoms Lasers, Department of Physics, Faculty of Sciences and Techniques, University Cheikh Anta Diop, Dakar, 5005, Senegal
| | - Ndeye Arame Boye Faye
- Laboratory of Atoms Lasers, Department of Physics, Faculty of Sciences and Techniques, University Cheikh Anta Diop, Dakar, 5005, Senegal; Senegalese Nuclear Safety and Security Regulatory Authority, Senegal
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Kita K, Igarashi Y, Kinase T, Hayashi N, Ishizuka M, Adachi K, Koitabashi M, Sekiyama TT, Onda Y. Rain-induced bioecological resuspension of radiocaesium in a polluted forest in Japan. Sci Rep 2020; 10:15330. [PMID: 32948784 PMCID: PMC7501248 DOI: 10.1038/s41598-020-72029-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 08/07/2020] [Indexed: 12/03/2022] Open
Abstract
It is the conventional understanding that rain removes aerosols from the atmosphere. However, the question of whether rain plays a role in releasing aerosols to the atmosphere has recently been posed by several researchers. In the present study, we show additional evidence for rain-induced aerosol emissions in a forest environment: the occurrence of radiocaesium-bearing aerosols in a Japanese forest due to rain. We carried out general radioactive aerosol observations in a typical mountainous village area within the exclusion zone in Fukushima Prefecture to determine the impacts and major drivers of the resuspension of radiocaesium originating from the nuclear accident in March 2011. We also conducted sampling according to the weather (with and without rain conditions) in a forest to clarify the sources of atmospheric radiocaesium in the polluted forest. We found that rain induces an increase in radiocaesium in the air in forests. With further investigations, we confirmed that the fungal spore sources of resuspended radiocaesium seemed to differ between rainy weather and nonrainy weather. Larger fungal particles (possibly macroconidia) are emitted during rainy conditions than during nonrainy weather, suggesting that splash generation by rain droplets is the major mechanism of the suspension of radiocaesium-bearing mould-like fungi. The present findings indicate that radiocaesium could be used as a tracer in such research fields as forest ecology, meteorology, climatology, public health and agriculture, in which fungal spores have significance.
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Affiliation(s)
- Kazuyuki Kita
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan.
| | - Yasuhito Igarashi
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan.
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-Nishi, Kumatori, Sennan, Osaka, 590-0494, Japan.
- Institute for Integrated Radiation and Nuclear Science, Kyoto University and College of Science, Ibaraki University, Formerly at Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, Japan.
| | - Takeshi Kinase
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
- Meteorological Research Institute and Formerly at College of Science, Ibaraki University, Ibaraki, Japan
| | - Naho Hayashi
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan
| | - Masahide Ishizuka
- Faculty of Engineering and Design, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan
| | - Kouji Adachi
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
| | - Motoo Koitabashi
- Forage Crop Protection Group, Division of Livestock Feeding and Management, Central Region Agricultural Research Center, National Agriculture and Food Research Organization, 768 Senbonmatsu, Nasushiobara, Tochigi, 329-2793, Japan
| | | | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
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Igarashi Y, Kita K, Maki T, Kinase T, Hayashi N, Hosaka K, Adachi K, Kajino M, Ishizuka M, Sekiyama TT, Zaizen Y, Takenaka C, Ninomiya K, Okochi H, Sorimachi A. Fungal spore involvement in the resuspension of radiocaesium in summer. Sci Rep 2019; 9:1954. [PMID: 30760819 PMCID: PMC6374464 DOI: 10.1038/s41598-018-37698-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 12/10/2018] [Indexed: 01/17/2023] Open
Abstract
We observed the atmospheric resuspension of radiocaesium, derived from the Fukushima Dai-ichi Nuclear Power Plant accident, at Namie, a heavily contaminated area of Fukushima, since 2012. During the survey periods from 2012 to 2015, the activity concentrations of radiocaesium in air ranged from approximately 10-5 to 10-2 Bq per m3 and were higher in the warm season than in the cold season. Electron microscopy showed that the particles collected on filters in summer were predominantly of biological origin (bioaerosols), with which the observed radiocaesium activity concentration varied. We conducted an additional aerosol analysis based on fluorescent optical microscopic observation and high-throughput DNA sequencing technique to identify bioaerosols at Namie in 2015 summer. The concentrations of bioaerosols fluctuated the order of 106 particles per m3, and the phyla Basidiomycota and Ascomycota (true Fungi) accounted for approximately two-thirds of the bioaerosols. Moreover, the fungal spore concentration in air was positively correlated with the radiocaesium concentration at Namie in summer 2016. The bioaerosol emissions from Japanese mixed forests in the temperate zone predominately included fungal cells, which are known to accumulate radiocaesium, and should be considered an important scientific issue that must be addressed.
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Affiliation(s)
- Yasuhito Igarashi
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan.
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan.
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba and Graduate School of Science and Engineering, Ibaraki University, and formerly at Meteorological Research Institute, Ibaraki, Japan.
| | - Kazuyuki Kita
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan.
| | - Teruya Maki
- Institute of Science and Engineering, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Takeshi Kinase
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan
- Meteorological Research Institute and formerly at College of Science, Ibaraki University, Ibaraki, Japan
| | - Naho Hayashi
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan
| | - Kentaro Hosaka
- Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki, 305-0005, Japan
| | - Kouji Adachi
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
| | - Mizuo Kajino
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
| | - Masahide Ishizuka
- Faculty of Engineering and Design, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan
| | | | - Yuji Zaizen
- Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052, Japan
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya, 464-8601, Japan
| | - Kazuhiko Ninomiya
- Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Hiroshi Okochi
- Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo, 169-8555, Japan
| | - Atsuyuki Sorimachi
- Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan
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Iwagami S, Tsujimura M, Onda Y, Nishino M, Konuma R, Abe Y, Hada M, Pun I, Sakaguchi A, Kondo H, Yamamoto M, Miyata Y, Igarashi Y. Temporal changes in dissolved 137Cs concentrations in groundwater and stream water in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 166:458-465. [PMID: 25975738 DOI: 10.1016/j.jenvrad.2015.03.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 02/11/2015] [Accepted: 03/08/2015] [Indexed: 06/04/2023]
Abstract
The concentration of dissolved 137Cs in groundwater and stream water in the headwater catchments in Yamakiya district, located ∼35 km north west of Fukushima Dai-ichi Nuclear Power Plant (FDNPP), was monitored from June 2011 to July 2013, after the earthquake and tsunami disaster. Groundwater and stream water were sampled at intervals of approximately 2 months at each site. Intensive sampling was also conducted during rainstorm events. Compared with previous data from the Chernobyl NPP accident, the concentration of dissolved 137Cs in stream water was low. In the Iboishi-yama catchment, a trend was observed for the concentration of dissolved 137Cs in stream water to decline, which could be divided into two phases by October 2011 (a fast flush of activity as a result of rapid washoff and a slow decline as a result of soil fixation and redistribution processes). The highest 137Cs concentration recorded at Iboishi-yama was 1.2 Bq/L on August 6, 2011, which then declined to 0.021-0.049 Bq/L during 2013 (in stream water under normal water-flow conditions). During the rainfall events, the concentration of dissolved 137Cs in stream water increased temporarily. The concentration of dissolved 137Cs in groundwater at a depth of 30 m at Iboishi-yama displayed a decreasing trend from 2011 to 2013, with a range from 0.039 Bq/L to 0.0025 Bq/L. The effective half-lives of stream water in the initial fast flush and secondary phases were 0.10-0.21 and 0.69-1.5 y, respectively in the three catchments. The effective half-life of groundwater was 0.46-0.58 y at Koutaishi-yama and 0.50-3.3 y at Iboishi-yama. The trend for the concentration of dissolved 137Cs to decline in groundwater and stream water was similar throughout 2012-2013, and the concentrations recorded in deeper groundwater were closer to those in stream water. The declining trend of dissolved 137Cs concentrations in stream water was similar to that of the loss of canopy 137Cs by throughfall, as shown in other reports of forest sites in the Yamakiya district.
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Affiliation(s)
- Sho Iwagami
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba 305-8577, Japan.
| | - Maki Tsujimura
- Department of Sustainable Environmental Studies, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Masataka Nishino
- Department of Geoenvironmental Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 305-8572, Japan
| | - Ryohei Konuma
- College of Geoscience, School of Life and Environmental Sciences, University of Tsukuba, 305-8572, Japan
| | - Yutaka Abe
- Department of Sustainable Environmental Studies, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Manami Hada
- Department of Sustainable Environmental Studies, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Ishwar Pun
- Department of Sustainable Environmental Studies, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Aya Sakaguchi
- Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 739-8526, Japan
| | - Hiroaki Kondo
- Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 739-8526, Japan
| | - Masayoshi Yamamoto
- Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, 923-1224, Japan
| | - Yoshiki Miyata
- Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, 923-1224, Japan
| | - Yasuhito Igarashi
- Atmospheric Environment and Applied Meteorology Research Department, Meteorological Research Institute, 305-0052, Japan
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Toyama C, Muramatsu Y, Igarashi Y, Aoyama M, Matsuzaki H. Atmospheric fallout of (129)I in Japan before the Fukushima accident: regional and global contributions (1963-2005). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8383-8390. [PMID: 23829385 DOI: 10.1021/es401596z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Atmospheric (129)I deposition was studied in different locations of Japan (Akita, Tsukuba, Tokyo, and Ishigaki Island) with samples collected between 1963 and 2005 in order to understand the distribution and sources of this nuclide and provide a reference deposition level prior to the Fukushima accident. Over this time period, the deposition pattern of (129)I in Tsukuba and Tokyo (on the Pacific side) differed from that of Akita (on the Japan Sea side). The primary source of deposition in Tsukuba and Tokyo is related to the (129)I discharge from domestic reprocessing in Tokai-mura. In contrast, the time-series pattern of deposition in Akita seems to have been influenced by (129)I discharges from reprocessing facilities in Europe and the transport of this radionuclide by westerly winds to coastlines of the Japan Sea. The (129)I deposition in Ishigaki (one of the southernmost islands in Japan) is influenced primarily by oceanic air masses (easterly winds), and deposition was 1 order of magnitude lower than that observed in Tsukuba and Tokyo. Cumulative (129)I deposition in Tokyo before the Fukushima accident was estimated at 13 mBq/m(2). The results of this study on deposition contribute to understanding the deposition levels of (129)I prior to the accident.
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Affiliation(s)
- Chiaki Toyama
- Department of Chemistry, Gakushuin University , 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
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