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Miyazaki K, Takehara M, Minomo K, Horie K, Takehara M, Yamasaki S, Saito T, Ohnuki T, Takano M, Shiotsu H, Iwata H, Vettese GF, Sarparanta MP, Law GTW, Grambow B, Ewing RC, Utsunomiya S. "Invisible" radioactive cesium atoms revealed: Pollucite inclusion in cesium-rich microparticles (CsMPs) from the Fukushima Daiichi Nuclear Power Plant. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134104. [PMID: 38569336 DOI: 10.1016/j.jhazmat.2024.134104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 04/05/2024]
Abstract
Understanding radioactive Cs contamination has been a central issue at Fukushima Daiichi and other nuclear legacy sites; however, atomic-scale characterization of radioactive Cs in environmental samples has never been achieved. Here we report, for the first time, the direct imaging of radioactive Cs atoms using high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). In Cs-rich microparticles collected from Japan, we document inclusions that contain 27 - 36 wt% of Cs (reported as Cs2O) in a zeolite: pollucite. The compositions of three pollucite inclusions are (Cs1.86K0.11Rb0.19Ba0.22)2.4(Fe0.85Zn0.84X0.31)2.0Si4.1O12, (Cs1.19K0.05Rb0.19Ba0.22)1.7(Fe0.66Zn0.32X0.41)1.4Si4.6O12, and (Cs1.27K0.21Rb0.29Ba0.15)1.9(Fe0.60Zn0.32X0.69)1.6Si4.4O12 (X includes other cations). HAADF-STEM imaging of pollucite, viewed along the [111] zone axis, revealed an array of Cs atoms, which is consistent with a simulated image using the multi-slice method. The occurrence of pollucite indicates that locally enriched Cs reacted with siliceous substances during the Fukushima meltdowns, presumably through volatilization and condensation. Beta radiation doses from the incorporated Cs are estimated to reach 106 - 107 Gy, which is more than three orders of magnitude less than typical amorphization dose of zeolite. The atomic-resolution imaging of radioactive Cs is an important advance for better understanding the fate of radioactive Cs inside and outside of nuclear reactors damaged by meltdown events.
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Affiliation(s)
- Kanako Miyazaki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masato Takehara
- 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
| | - Kenji Horie
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan, Hayama, Kanagawa 240-0193, Japan
| | - Mami Takehara
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan
| | - Shinya Yamasaki
- Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Takumi Saito
- Nuclear Professional School, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Masahide Takano
- Japan Atomic Energy Agency, Nuclear Science Research Institute, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Hiroyuki Shiotsu
- Japan Atomic Energy Agency, Nuclear Science Research Institute, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Hajime Iwata
- Japan Atomic Energy Agency, Nuclear Fuel Cycle Engineering Laboratories, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194, Japan
| | - Gianni F Vettese
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Mirkka P Sarparanta
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, the Nantes University, Nantes 44307, France
| | - Rodney C Ewing
- Earth & Planetary Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115 USA
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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Liu M, Taira Y, Matsuo M, Orita M, Matsunaga H, Kashiwazaki Y, Xiao X, Takamura N. Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant. Sci Rep 2023; 13:22459. [PMID: 38105319 PMCID: PMC10725873 DOI: 10.1038/s41598-023-49821-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023] Open
Abstract
Temporal variation and fluctuation in environmental contamination in Futaba town and Okuma town, the location of the Fukushima Daiichi Nuclear Power Plant (FDNPP), were evaluated based on a car-borne survey conducted from October 2021 to November 2022. Although the environmental radioactivity in the interim storage facility area (ISF) was higher than that in open areas (i.e., the evacuation order lifted areas in Futaba town and the Specific Reconstruction and Regeneration Base area [SRRB] in Okuma town), only minor temporal changes were seen in the ambient dose and detection rate of radiocesium (the proportion of radiocesium detected points per all measuring points) in those areas, respectively. These findings suggest that the observed variations may result from physical decay and environmental remediation. Resuspension caused by human activities and weather could also affect the detection rate of radiocesium. The annual external effective doses in Futaba town and Okuma town were estimated to be at a limited level (< 1 mSv/year). Nevertheless, to help ensure the safety and future prosperity of residents and communities in the affected areas around the FDNPP, long-term follow-up monitoring of temporal exposure dose levels during the recovery and reconstruction phases is extremely important.
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Affiliation(s)
- Mengjie Liu
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
| | - Yasuyuki Taira
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
- Fukushima Global Medical Science Center and Radiation Medical Science Center for the Fukushima Health Management Survey Fukushima Medical University, Fukushima City, Fukushima Prefecture, Japan
| | - Masahiko Matsuo
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
| | - Makiko Orita
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
- Fukushima Global Medical Science Center and Radiation Medical Science Center for the Fukushima Health Management Survey Fukushima Medical University, Fukushima City, Fukushima Prefecture, Japan
| | - Hitomi Matsunaga
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
| | - Yuya Kashiwazaki
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
| | - Xu Xiao
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan
| | - Noboru Takamura
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture, 852-8523, Japan.
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Fueda K, Komiya T, Minomo K, Horie K, Takehara M, Yamasaki S, Shiotsu H, Ohnuki T, Grambow B, Law GW, Ewing R, Utsunomiya S. Occurrence of radioactive cesium-rich micro-particles (CsMPs) in a school building located 2.8 km south-west of the Fukushima Daiichi Nuclear Power Plant. CHEMOSPHERE 2023; 328:138566. [PMID: 37011818 DOI: 10.1016/j.chemosphere.2023.138566] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
Radioactive Cs-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) are a potential health risk through inhalation. Little has been documented on the occurrence of CsMPs, particularly their occurrence inside buildings. In this study, we quantitatively analyze the distribution and number of CsMPs in indoor dust samples collected from an elementary school located 2.8 km to the southwest of FDNPP. The school had remained deserted until 2016. Then, using a modified version of the autoradiography-based "quantifying CsMPs (mQCP) method," we collected samples and determined the number of CsMPs and Cs radioactive fraction (RF) values of the microparticles (defined as total Cs activity from CsMPs/bulk Cs activity of the entire sample). The numbers of CsMPs ranged from 653 to 2570 particles/(g dust) and 296-1273 particles/(g dust) on the first and second floors of the school, respectively. The corresponding RFs ranged between 6.85 - 38.9% and 4.48-6.61%, respectively. The number of CsMPs and RF values in additional outdoor samples collected near the school building were 23-63 particles/(g dust or soil) and 1.14-1.61%, respectively. The CsMPs were most abundant on the school's first floor near to the entrance, and the relative abundance was higher near the stairs on the second floor, indicating a likely CsMP dispersion path through the building. Additional wetting of the indoor samples combined with autoradiography revealed that indoor dusts had a distinct absence of intrinsic, soluble Cs species, such as CsOH. These combined observations indicate that a significant amount of poorly soluble CsMPs were likely contained in initial radioactive airmass plumes from the FDNPP and that the microparticles penetrated buildings. CsMPs could still be abundant at the location, with locally high Cs activity in indoor environments near to openings.
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Affiliation(s)
- Kazuki Fueda
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Tatsuki Komiya
- 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
| | - Kenji Horie
- National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo, 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa, 240-0193, Japan
| | - Mami Takehara
- National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo, 190-8518, Japan
| | - Shinya Yamasaki
- Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 Japan
| | - Hiroyuki Shiotsu
- Nuclear Safety Research Center, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-Mura, Naka-Gun, Ibaraki, 319-1195, Japan
| | - Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, The University of Nantes, Nantes, 44307, France
| | - GarethT W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - RodneyC Ewing
- Department of Earth and Planetary Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA, 94305-2115, USA
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Ueno S, Hasegawa Y, Kato S, Mori H, Tsukada H, Ohira H, Kaneko S. Rapid survey of de novo mutations in naturally growing tree species following the March 2011 disaster in Fukushima: The effect of low-dose-rate radiation. ENVIRONMENT INTERNATIONAL 2023; 174:107893. [PMID: 37058973 DOI: 10.1016/j.envint.2023.107893] [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: 12/11/2022] [Revised: 02/13/2023] [Accepted: 03/17/2023] [Indexed: 06/19/2023]
Abstract
The impact of low-dose-rate radiation on genetics is largely unknown, particularly in natural environments. The Fukushima Dai-ich Nuclear Power Plant disaster resulted in the creation of contaminated natural lands. In this study, de novo mutations (DNMs) in germ line cells were surveyed from double-digest RADseq fragments in Japanese cedar and flowering cherry trees exposed to ambient dose rates ranging from 0.08 to 6.86 μGy h-1. These two species are among the most widely cultivated Japanese gymnosperm and angiosperm trees for forestry and horticultural purpose, respectively. For Japanese flowering cherry, open crossings were performed to produce seedlings, and only two candidate DNMs were detected from uncontaminated area. For Japanese cedar, the haploid megagametophytes were used as next generation samples. The use of megagametophytes from open crossing for next generation mutation screening had many advantages such as reducing exposure to radiation in contaminated areas because artificial crossings are not needed and the ease of data analysis owing to the haploid nature of megagametophytes. A direct comparison of the nucleotide sequences of parents and megagametophytes revealed an average of 1.4 candidate DNMs per megagametophyte sample (range: 0-40) after filtering procedures were optimized based on the validation of DNMs via Sanger sequencing. There was no relationship between the observed mutations and the ambient dose rate in the growing area or the concentration of 137Cs in cedar branches. The present results also suggest that mutation rates differ among lineages and that the growing environment has a relatively large influence on these mutation rates. These results suggested there was no significant increase in the mutation rate of the germplasm of Japanese cedar and flowering cherry trees growing in the contaminated areas.
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Affiliation(s)
- Saneyoshi Ueno
- Department of Forest Molecular Genetics and Biotechnology, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan.
| | - Yoichi Hasegawa
- Department of Forest Molecular Genetics and Biotechnology, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Shuri Kato
- Department of Forest Molecular Genetics and Biotechnology, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan; Tama Forest Science Garden, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1833-81 Todori, Hachioji, Tokyo 193-0843, Japan
| | - Hideki Mori
- Department of Forest Molecular Genetics and Biotechnology, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan
| | - Hajime Ohira
- Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan
| | - Shingo Kaneko
- Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan.
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Taira Y, Matsuo M, Orita M, Matsunaga H, Takamura N, Hirao S. Assessment of localized and resuspended 137 Cs due to decontamination and demolition in the difficult-to-return zone of Tomioka town, Fukushima Prefecture. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:1555-1563. [PMID: 35485214 PMCID: PMC9790190 DOI: 10.1002/ieam.4625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/23/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
As the next step that occurred more than one decade after the accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS), decontamination and demolition have been carried out in the Specified Reconstruction and Revitalization Base (SRRB) of the difficult-to-return zone around the FDNPS. However, the risk of internal exposure among workers due to airborne dust inhalation after building demolition operations has not been sufficiently evaluated. To evaluate the working environment and internal exposure risk due to inhalation in the SRRB of Tomioka town, Fukushima Prefecture, the cesium-137 (137 Cs) radioactivity levels in the airborne dust at building demolition sites were analyzed using gamma spectrometry. The 137 Cs radioactivity levels and resuspension factors of the airborne dust at the subject building sites in the difficult-to-return zone remained at high levels compared with those of the control, which was located in the evacuation order-lifted area in Tomioka town. However, the 137 Cs radioactivity levels did not increase significantly, despite demolition operations that used heavy machinery. In this case, no substantial increases in accident-derived 137 Cs levels due to decontamination and demolition in the SRRB of Tomioka town, Fukushima Prefecture, were observed in the airborne dust samples, which suggests that the 137 Cs radioactivity in the airborne dust is primarily associated with particles that are resuspended by localized winds accompanied by the transfer of construction vehicles as opposed to the decontamination and demolition operations. However, the internal exposure doses due to aspirating airborne dust containing 137 Cs were extremely low compared with the estimated annual effective doses of decontamination workers or the limits recommended by the Japanese government. Additionally, countermeasures such as wearing protective masks could help reduce the on-site inhalation of soil-derived radionuclides. Integr Environ Assess Manag 2022;18:1555-1563. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Yasuyuki Taira
- Department of Global HealthMedicine and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Atomic Bomb Disease InstituteNagasaki CityNagasaki PrefectureJapan
| | - Masahiko Matsuo
- Department of Global HealthMedicine and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Atomic Bomb Disease InstituteNagasaki CityNagasaki PrefectureJapan
| | - Makiko Orita
- Department of Global HealthMedicine and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Atomic Bomb Disease InstituteNagasaki CityNagasaki PrefectureJapan
| | - Hitomi Matsunaga
- Department of Global HealthMedicine and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Atomic Bomb Disease InstituteNagasaki CityNagasaki PrefectureJapan
| | - Noboru Takamura
- Department of Global HealthMedicine and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Atomic Bomb Disease InstituteNagasaki CityNagasaki PrefectureJapan
- Institute of Environmental Radioactivity, Fukushima UniversityFukushima CityFukushima PrefectureJapan
| | - Shigekazu Hirao
- Institute of Environmental Radioactivity, Fukushima UniversityFukushima CityFukushima PrefectureJapan
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Katengeza EW, Ochi K, Sanada Y, Iimoto T, Yoshinaga S. The Effect and Effectiveness of Decontaminating a Pond in a Residential Area of Fukushima. HEALTH PHYSICS 2021; 121:48-57. [PMID: 33867431 DOI: 10.1097/hp.0000000000001413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
ABSTRACT Special reconstruction and revitalization bases were designated in Fukushima's difficult-to-return zone by the Japanese government as targets of intensive decontamination to drastically lower air dose rates and enable residents to return. A pond amid residences of one of these bases was targeted for decontamination, and this study aimed at evaluating the effect and effectiveness of the decontamination using decontamination factor, air dose rate reduction factor, and the additional annual effective dose to residents. Air dose rates were measured in situ with the second-generation Kyoto University Radiation Mapping system, while soil core samples were collected and measured for radioactivity in the laboratory by gamma spectrometry. Lower decontamination factors were observed for more deeply distributed radiocesium soil profiles, whereas areas covered with gravel demonstrated the largest reduction in air dose rates. Decontamination effectively lowered the radiocesium inventory and air dose rates by 51-93% and 37-91%, respectively. Moreover, the additional annual effective dose to the public changed from 1.7 ± 0.79 mSv to 1.2 ± 0.57 mSv because of decontamination representing a dose aversion of 29%. These findings demonstrate how decontaminating ponds in residential areas can help to further lower the external exposure.
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Affiliation(s)
- Estiner Walusungu Katengeza
- Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan
| | - Kotaro Ochi
- Fukushima Environmental Monitoring Division, Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency; 45-169, Kaihama-Sukakeba, Minamisoma, Fukushima, 975-0036, Japan
| | - Yukihisa Sanada
- Fukushima Environmental Monitoring Division, Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency; 45-169, Kaihama-Sukakeba, Minamisoma, Fukushima, 975-0036, Japan
| | - Takeshi Iimoto
- Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan
| | - Shinji Yoshinaga
- Research Institute for Radiation Biology and Medicine, Hiroshima University; 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
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Salh H, Külahcı F, Aközcan S. A mobile simulation and ARIMA modeling for prediction of air radiation dose rates. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07726-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Yamaguchi T, Taira Y, Matsuo M, Orita M, Yamada Y, Takamura N. LOCAL LEVELS OF RADIATION EXPOSURE DOSES DUE TO RADIOCESIUM FOR RETURNED RESIDENTS IN TOMIOKA TOWN, FUKUSHIMA PREFECTURE. RADIATION PROTECTION DOSIMETRY 2021; 193:207-220. [PMID: 33876245 DOI: 10.1093/rpd/ncab049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/26/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Tomioka Town is located within a 20-km radius of the Fukushima Daiichi Nuclear Power Station. Radiation dose rates due to radiocesium in residents' living spaces were evaluated from the measurements of ambient dose rates and environmental samples after returning home. The mean ambient dose rates were 0.15-0.18-μSv/h indoors and 0.23-0.26-μSv/h outdoors during 2018 and 2019, and the additional radiation dose rates were calculated to be 1.4 mSv/y in 2018 and 1.1 mSv/y in 2019. Ambient dose equivalent from surface soils within housing sites were estimated to be 0.66 mSv/y in 2018 and 0.54 mSv/y in 2019. Moreover, committed effective doses from local foods were calculated in 19-74 μSv/y for children and 39-100 μSv/y for adults during 2018 and 2019. These findings suggest that current radiation exposure doses have been controlled at the levels close to the public dose limit (1 mSv/y) in residents' living spaces.
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Affiliation(s)
| | | | - Masahiko Matsuo
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture 852-8523, Japan
| | - Makiko Orita
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture 852-8523, Japan
| | - Yumiko Yamada
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture 852-8523, Japan
| | - Noboru Takamura
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki Prefecture 852-8523, Japan
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Taira Y, Matsuo M, Yamaguchi T, Yamada Y, Orita M, Takamura N. Radiocesium levels in contaminated forests has remained stable, even after heavy rains due to typhoons and localized downpours. Sci Rep 2020; 10:19215. [PMID: 33154394 PMCID: PMC7645623 DOI: 10.1038/s41598-020-75857-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 10/16/2020] [Indexed: 11/09/2022] Open
Abstract
In recent years, Japan has suffered serious damage due to natural disasters such as earthquakes, heavy rains due to tropical storms (typhoons) and localized downpours. To assess the chronological changes in the attenuation of external exposure doses and environmental radiation contamination due to the rainfall associated with typhoons and heavy rains during October to December 2019 in Fukushima, we measured environmental radiation levels in forest areas along the Mt Okura hiking trail in Tomioka Town, Fukushima Prefecture, near the Fukushima Daiichi Nuclear Power Station. We confirmed that (1) current ambient dose rates of 0.38-0.95 μSv/h in most forest areas were 79.9-84.7% higher than in residential areas; (2) the number of sites along the hiking trail where 137Cs was detected was limited (1.1-4.7%); and (3) individual dose rates of 0.21-0.34 μSv/h were lower than ambient dose rates. These findings suggest that radiocesium has remained stable in natural forests that have not been decontaminated even though current levels are low, despite the occurrence of heavy rainfall associated with Super Typhoon Hagibis in 2019 and localized downpours. Hiking while managing exposure to environmental contamination using a personal dosimeter may be the safest model for spending time of leisure activities.
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Affiliation(s)
- Yasuyuki Taira
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan.
| | - Masahiko Matsuo
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan
| | - Takumi Yamaguchi
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan
| | - Yumiko Yamada
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan
| | - Makiko Orita
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan
| | - Noboru Takamura
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan
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