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Hirose K, Onda Y, Tsukada H, Hiroyama Y, Okada Y, Kikawada Y. Chemical implication of the partition coefficient of 137Cs between the suspended and dissolved phases in natural water. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 278:107486. [PMID: 38936250 DOI: 10.1016/j.jenvrad.2024.107486] [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: 10/27/2023] [Revised: 06/17/2024] [Accepted: 06/17/2024] [Indexed: 06/29/2024]
Abstract
After the Fukushima Daiichi nuclear power plant accident, the terrestrial environment became severely contaminated with radiocesium. Consequently, the river and lake water in the Fukushima area exhibited high radiocesium levels, which declined subsequently. The partition coefficient of 137Cs between the suspended sediment (SS) and dissolved phases, Kd, was introduced to better understand the dynamic behavior of 137Cs in different systems. However, the Kd values in river water, ranging from 2 × 104 to 7 × 106 L kg-1, showed large spatiotemporal variability. Therefore, the factors controlling the 137Cs partition coefficient in natural water systems should be identified. Herein, we introduce a chemical model to explain the variability in 137Cs Kd in natural water systems. The chemical model includes the complexation of Cs+ with mineral and organic binding sites in SS, metal exchange reactions, and the presence of colloidal species. The application of the chemical model to natural water systems revealed that Cs+ is strongly associated with binding sites in SS, and a major chemical interaction between 137Cs and the binding sites in SS is the isotope exchange reaction between stable Cs and 137Cs, rather than metal exchange reactions with other metal ions such as potassium ions. To explain the effect of the SS concentration on Kd, the presence of colloidal 137Cs passing through a filter is significant as the dominant dissolved species of 137Cs in river water. These results suggest that a better understanding of stable Cs dissolved in natural water is important for discerning the geochemical and ecological behaviors of 137Cs in natural water.
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Affiliation(s)
- Katsumi Hirose
- Laboratory for Environmental Research at Mount Fuji, Shujyuku-ku, Tokyo, 169-0072, Japan.
| | - Yuichi Onda
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, Ibaraki, 305-0006, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima-City, Fukushima, 960-1296, Japan
| | - Yuko Hiroyama
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Kioi-Cho, Chiyoda-ku, Tokyo, 102-8554, Japan
| | - Yukiko Okada
- Atomic Energy Laboratory, Tokyo City University, Ozenji 971, Asao-ku, Kawasaki, 215-0031, Japan
| | - Yoshikazu Kikawada
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Kioi-Cho, Chiyoda-ku, Tokyo, 102-8554, Japan
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2
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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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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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Ma S, Yang H, Fu S, He P, Duan X, Yang Z, Jia D, Colombo P, Zhou Y. Additive manufacturing of geopolymers with hierarchical porosity for highly efficient removal of Cs . JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130161. [PMID: 36327833 DOI: 10.1016/j.jhazmat.2022.130161] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/26/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Geopolymers (GPs) have emerged as promising adsorbents for wastewater treatment due to their superior adsorption stability, tunable porosity, high adsorption capacity, and low-energy production. Despite their great promise, developing GPs with well-controlled hierarchical structures and high porosity remains challenging, and the mechanism underlying the ion adsorption process remains elusive. Here we report a cost-effective and universal approach to fabricate Na or K GPs with sophisticated architectures, high porosity, and arbitrary cation species exchange by means of additive manufacturing and a surfactant. The introduction of sodium lauryl sulfate (SLS) enhanced the porosity of the GP adsorbents, yielding NaGP-lattice-10%SLS adsorbent with a high total porosity of 80.8 vol%. Combining static and dynamic adsorption tests, the effects of morphology, surfactant content, and cation species on Cs+ adsorption performance were systemically investigated. With an initial Cs+ concentration of 900 mg/L, the printed NaGP exhibited a maximum Cs+ adsorption capacity of 80.1 mg/g, outperforming other adsorbents reported so far. The quasi-second-order fit of the NaGP adsorbent showed overall higher R2 values than the quasi-first-order fit, indicating that the adsorption process was dominated by ion exchange. Combined with first-principles calculations, we verified that the content of water in the GP sod cages also affected the ion-exchange process between Na+ and Cs+.
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Affiliation(s)
- Siqi Ma
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China
| | - Hualong Yang
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China
| | - Shuai Fu
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Peigang He
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China.
| | - Xiaoming Duan
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China
| | - Zhihua Yang
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China
| | - Dechang Jia
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China.
| | - Paolo Colombo
- Department of Industrial Engineering, University of Padova, Padova, Italy; Department of Materials Science and Engineering, The Pennsylvania State University, Philadelphia, USA
| | - Yu Zhou
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin, China
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5
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Zhu J, Xu C, Chen C, Zhang A, Shao J, Zhang Q. Solution to the particle concentration effect on determining K d value of radionuclides. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 255:107028. [PMID: 36206605 DOI: 10.1016/j.jenvrad.2022.107028] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/10/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
The particle concentration effect on Kd values of radionuclides has been observed but the underlying mechanism remains controversial. The hope is to use the relationship between particle concentration, adsorption-desorption isotherms and reversibility, in combination with surface component activity of model (SCA model), to solve this issue. 137Cs, 60Co, 90Sr were used as tracers, batch experiments were conducted in freshwater-sediment and seawater-sediment. The experiment of each radionuclide was designed with five different particle concentrations Cp, and for each Cp there were seven different initial concentrations C0. After adsorption experiments, four consecutive desorption experiments were carried out. At the fourth desorption experiment, radionuclide concentrations in the supernatant and sediment were measured. The results showed that adsorption and single desorption data of 137Cs, 60Co, 90Sr might be described by linear isotherms. 137Cs was reversible in the seawater-sediment, so hysteresis angles of the five-particle concentration were approximately 0°, all adsorption and desorption data could be classified into one line. In the remaining systems, besides the adsorption and single desorption isotherms moved upward with the decrease of particle concentration, hysteresis angles and irreversibility also increased, thus, the particle concentration effect was obvious. The reversible and resistant component concentrations calculated by adsorption, single desorption and consecutive desorption isotherm were linear functions of equilibrium concentration Ce1, respectively. Data from adsorption and desorption experiments with particle concentration effect could be classified into the same line using the Freundlich-SCA model. The results of this study indicate that the particle concentration effect is related to reversibility. When adsorption isotherm and single desorption isotherm are both linear, consecutive desorption isotherm, reversible and resistant component concentrations approach linearity too. After the Freundlich-SCA model eliminated the particle concentration effect on adsorption and desorption data, the data can be used to predict the adsorption, single desorption isotherm and Kd value at any particle concentration.
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Affiliation(s)
- Jun Zhu
- School of Water Resources & Environment, China University of Geosciences, Beijing, PR China; Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, PR China
| | - Chenglong Xu
- China Appraisal Center for Environment and Engineering, Ministry of Ecology and Environment, Beijing, PR China; State Environmental Protection Key Laboratory of Numerical Modeling for Environmental Impact Assessment, Beijing, PR China
| | - Chao Chen
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, PR China
| | - Aiming Zhang
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, PR China
| | - Jingli Shao
- School of Water Resources & Environment, China University of Geosciences, Beijing, PR China
| | - Qiulan Zhang
- School of Water Resources & Environment, China University of Geosciences, Beijing, PR China.
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Kambayashi S, Zhang J, Narita H. Significance of Fukushima-derived radiocaesium flux via river-estuary-ocean system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 793:148456. [PMID: 34328972 DOI: 10.1016/j.scitotenv.2021.148456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
The environmental dynamics of Fukushima-derived radiocaesium from land to ocean and the impact of its flux on the marine environment are matters of concern because radiocaesium will be continually transported to the open ocean for the next several decades, or possibly more than one hundred years. In order to assess the distribution and flux of radiocaesium in a river-estuary-ocean system, we investigated the activity concentration of radiocaesium in Matsukawa-ura Lagoon, the largest lagoon in Fukushima, where it is very easy to carry out observations with a wide salinity gradient. Activity concentrations of dissolved 137Cs are elevated in seawater of low to intermediate salinity. It can thus be inferred that radiocaesium desorbs from suspended particles in an estuarine area. The porewater activity concentration of 137Cs in lagoon sediment was about 10 times higher than that in the overlying lagoon water. This direct measurement indicates that a significant amount of radiocaesium in sediment desorbs into porewater. From the results of a mass balance model, dissolved 137Cs flux from the lagoon's bottom is 15.3 ± 3.7 times greater than the riverine input, including desorption from particles. In the case of the whole Pacific coast of northeastern Japan (Miyagi, Fukushima, and Ibaraki Prefectures), dissolved 137Cs flux into the open ocean, including diffusion of porewater, is estimated to be up to 1.5 times greater than the sum of riverine input and the ongoing release from the Fukushima Dai-ichi Nuclear Power Station's harbor. Consequently, our results suggest that radiocaesium is transported to the open ocean under the control of various processes, not only by desorption from particles but also, for example, by the diffusion of porewater.
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Affiliation(s)
- Shota Kambayashi
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Jing Zhang
- Faculty of Science, Academic Assembly, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
| | - Hisashi Narita
- School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu-ku, Shizuoka 424-8610, Japan
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Yamasaki S, Utsunomiya S. A review of efforts for volume reduction of contaminated soil in the ten years after the accident at the Fukushima Daiichi Nuclear Power Plant. J NUCL SCI TECHNOL 2021. [DOI: 10.1080/00223131.2021.1974596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Shinya Yamasaki
- Department of Chemistry, Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Ikenoue T, Takehara M, Morooka K, Kurihara E, Takami R, Ishii N, Kudo N, Utsunomiya S. Occurrence of highly radioactive microparticles in the seafloor sediment from the pacific coast 35 km northeast of the Fukushima Daiichi nuclear power plant. CHEMOSPHERE 2021; 267:128907. [PMID: 33220981 DOI: 10.1016/j.chemosphere.2020.128907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
To understand the properties and significance of highly radioactive particles in the marine environment, we have examined seafloor sediment with a radioactivity of ∼1200 Bq/kg (dry weight; after decay correction to March 2011) collected 35 km northeast of the Fukushima Daiichi Nuclear Power Plant (FDNPP). Among the 697 highly radioactive particles separated from the sediment, two particles, D1-MAX and D1-MID, had a total Cs radioactivity of ∼56 and 0.67 Bq (after decay correction to March 2011), respectively. These particles were characterized with a variety of electron microscopic techniques, including transmission electron microscopy. The 134Cs/137Cs radioactivity ratio of D1-MAX, 1.04, was comparable to that calculated for Unit 2 or 3. D1-MAX consisted mainly of a Cs-rich microparticle (CsMP) with a silica glass matrix. The data clearly suggested that D1-MAX resulted from a molten core-concrete interaction during meltdowns. In contrast, D1-MID was an aggregate of plagioclase, quartz, anatase, and Fe-oxide nanoparticles as well as clay minerals, which had adsorbed soluble Cs. D1-MID was likely a terrestrial particle that had been transported by wind and/or ocean currents to a site 35 km from the FDNPP. The radioactive fractions of D1-MAX and D1-MID were 15% and 0.36%, respectively, of the total radioactivity in the bulk sediment. These highly radioactive particles have a great impact on the movement of radioactive Cs in the marine environment by carrying condensed Cs radioactivity with various colloidal and desorption properties depending on the host phase.
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Affiliation(s)
- Takahito Ikenoue
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba, Japan.
| | - Masato Takehara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Eitaro Kurihara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Ryu Takami
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Nobuyoshi Ishii
- Biospheric Assessment for Waste Disposal Team & Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology, Anagawa 4-9-1, Inage, Chiba, Japan
| | - Natsumi Kudo
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba, Japan
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
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9
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Kurihara E, Takehara M, Suetake M, Ikehara R, Komiya T, Morooka K, Takami R, Yamasaki S, Ohnuki T, Horie K, Takehara M, Law GTW, Bower W, W Mosselmans JF, Warnicke P, Grambow B, Ewing RC, Utsunomiya S. Particulate plutonium released from the Fukushima Daiichi meltdowns. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140539. [PMID: 32663681 DOI: 10.1016/j.scitotenv.2020.140539] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/20/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Traces of Pu have been detected in material released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March of 2011; however, to date the physical and chemical form of the Pu have remained unknown. Here we report the discovery of particulate Pu associated with cesium-rich microparticles (CsMPs) that formed in and were released from the reactors during the FDNPP meltdowns. The Cs-pollucite-based CsMP contained discrete U(IV)O2 nanoparticles, <~10 nm, one of which is enriched in Pu adjacent to fragments of Zr-cladding. The isotope ratios, 235U/238U, 240Pu/239Pu, and 242Pu/239Pu, of the CsMPs were determined to be ~0.0193, ~0.347, and ~0.065, respectively, which are consistent with the calculated isotopic ratios of irradiated-fuel fragments. Thus, considering the regional distribution of CsMPs, the long-distance dispersion of Pu from FNDPP is attributed to the transport by CsMPs that have incorporated nanoscale fuel fragments prior to their dispersion up to 230 km away from the Fukushima Daiichi reactor site.
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Affiliation(s)
- Eitaro Kurihara
- 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
| | - Mizuki Suetake
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ryohei Ikehara
- 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
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ryu Takami
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, 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
| | - 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
| | - 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
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki 00014, Finland
| | - William Bower
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki 00014, Finland
| | | | - Peter Warnicke
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, The University of Nantes, Nantes 44307, France
| | - Rodney C Ewing
- Department of Geological 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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10
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Takata H, Aono T, Aoyama M, Inoue M, Kaeriyama H, Suzuki S, Tsuruta T, Wada T, Wakiyama Y. Suspended Particle-Water Interactions Increase Dissolved 137Cs Activities in the Nearshore Seawater during Typhoon Hagibis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10678-10687. [PMID: 32786583 DOI: 10.1021/acs.est.0c03254] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Distributions of 137Cs in dissolved and particulate phases of the downstream reaches of seven rivers and adjacent nearshore and offshore waters as far as ∼60 km south of the Fukushima Dai-ichi nuclear power plant (FDNPP) were studied during the high-river-flow period (June-September 2019) and during the period of October 2019 after typhoon Hagibis. Dissolved 137Cs activities in nearshore water were higher than those in rivers and offshore waters, and this distribution was more intensified after the typhoon, indicating the desorption of 137Cs from riverine suspended particles in addition to the ongoing release of contaminated water from the FDNPP and re-entry of radiocesium via submarine groundwater discharge. This scenario is also supported by the reduction of distribution coefficient (Kd) from a geometric mean value of 5.5 × 105 L/kg in rivers to 9.8 × 104 L/kg in nearshore water. The occupation of desorbed 137Cs to the dissolved activity of this nuclide in nearshore water was estimated to be 0.7%-20% (median: 9.7%) during the high-river-flow period, increasing to 1.4%-66% (32.3%) after the typhoon, suggesting that the desorption during the flood period such as typhoons further contributes to the increase in dissolved 137Cs levels in nearshore water.
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Affiliation(s)
- Hyoe Takata
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan
| | - Tatsuo Aono
- Center for Advanced Radiation Emergency Medicine, National Institutes for Quantum and Radiological Science and Technology, Fukushima, Fukushima 960-1295, Japan
| | - Michio Aoyama
- Life and Environmental Science,Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Mutsuo Inoue
- Low Level Radioactivity Laboratory, Kanazawa University, Nomi, Ishikawa 923-1224, Japan
| | - Hideki Kaeriyama
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa 236-8648, Japan
| | - Shotaro Suzuki
- Fukushima Prefectural Fisheries and Marine Science Research Centre, Iwaki, Fukushima 970-0316, Japan
| | - Tadahiko Tsuruta
- Japan Atomic Energy Agency, Minamisouma, Fukushima 975-0036, Japan
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan
| | - Yoshifumi Wakiyama
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan
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11
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Delaval A, Duffa C, Radakovitch O. A review on cesium desorption at the freshwater-seawater interface. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 218:106255. [PMID: 32421587 DOI: 10.1016/j.jenvrad.2020.106255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
Understanding the processes governing the behavior of radiocesium in the sea is still essential to make accurate assessments of its potential impacts on marine ecosystems. One of the most important of this process is the desorption that may occur at the river-sea interface due to changes in physico-chemical conditions, including ionic strength and solution composition. It has been the subject of many studies using field measurements or laboratory experiments, but there was no global interpretation of these works and their results. The present review summarizes relevant laboratory experiments studying desorption of Cs (stable or radioactive) from particles in sea or brackish waters. To date, 32 experimental studies have been carried out on 68 Cs-bearing samples since 1964. A wide range of desorbed fraction (0-86%) was observed, partly depending on the experimental design. For particles containing radiocesium issued from a contamination in the environment, the desorption ranges from 0 to 64% of the particulate activity, with a median at only 3%. Particles contaminated in laboratory show a range between 6 and 86% with a multimodal distribution. The desorption initiates at low salinity (3-4) and rapidly reaches a threshold around 10-15. Laboratory experiments show that two first-order reactions govern the kinetics of the process, with half-life reaction times of 1 h and a few days. These two reactions are probably linked to the adsorption of Cs onto different particles sites. Also, the dynamic of Cs desorption depends on its initial distribution on these different sites, in relation with the history of its contamination and an aging effect.
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Affiliation(s)
- A Delaval
- IRSN (Institut de Radioprotection et de Sûreté Nucléaire), PSE-ENV/SRTE/LRTA, 13115, Saint-Paul-Les-Durance, France.
| | - C Duffa
- IRSN (Institut de Radioprotection et de Sûreté Nucléaire), PSE-ENV/SRTE/LRTA, 13115, Saint-Paul-Les-Durance, France
| | - O Radakovitch
- IRSN (Institut de Radioprotection et de Sûreté Nucléaire), PSE-ENV/SRTE/LRTA, 13115, Saint-Paul-Les-Durance, France; Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, France
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12
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Ikehara R, Morooka K, Suetake M, Komiya T, Kurihara E, Takehara M, Takami R, Kino C, Horie K, Takehara M, Yamasaki S, Ohnuki T, Law GTW, Bower W, Grambow B, Ewing RC, Utsunomiya S. Abundance and distribution of radioactive cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant into the environment. CHEMOSPHERE 2020; 241:125019. [PMID: 31610456 DOI: 10.1016/j.chemosphere.2019.125019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/27/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
The abundance and distribution of highly radioactive cesium-rich microparticles (CsMPs) that were released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the first stage of the nuclear disaster in March 2011 are described for 20 surface soils collected around the FDNPP. Based on the spatial distribution of the numbers (particles/g) and radioactive fraction (RF) of the CsMPs in surface soil, which is defined as the sum of the CsMP radioactivity (in Bq) divided by the total radioactivity (in Bq) of the soil sample, three regions of particular interest have been identified: i.) near-northwest (N-NW), ii.) far-northwest (F-NW), and iii.) southwest (SW). In these areas, the number and RF of CsMPs were determined to be 22.1-101 particles/g and 15.4-34.0%, 24.3-64.8 particles/g and 36.7-37.4%, and 0.869-8.00 particles/g and 27.6-80.2%, respectively. These distributions are consistent with the plume trajectories of material released from the FDNPP on March 14, 2011, in the late afternoon through to the late afternoon of March 15, 2011, indicating that the CsMPs formed only during this short period. Unit 3 is the most plausible source of the CsMPs at the beginning of the release based on an analysis of the sequence of release events. The lower RF values in the N-NW region indicate a larger influence from subsequent plumes that mainly consisted of soluble Cs species formed simultaneously with precipitation. The quantitative map of the distribution of CsMPs provides an important understanding of CsMP dispersion dynamics and can be used to assess risks in inhabited regions.
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Affiliation(s)
- Ryohei Ikehara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Mizuki Suetake
- 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
| | - Eitaro Kurihara
- 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
| | - Ryu Takami
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Chiaki Kino
- The Institute of Applied Energy, 1-14-2 Nishi-shimbashi, Minato-ku, Tokyo, 105-0003, 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
| | - 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
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - William Bower
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, the University of Nantes, Nantes, 44307, France
| | - Rodney C Ewing
- Department of Geological 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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13
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Takata H, Inatomi N, Kudo N. The contribution of 137Cs export flux from the Tone River Japan to the marine environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 701:134550. [PMID: 31726417 DOI: 10.1016/j.scitotenv.2019.134550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
The contribution of 137Cs transport to the marine environment via the Tone River, Japan was investigated. This river has the largest discharge among rivers on the North Pacific side of eastern Japan. The sampling site was located upstream near the river mouth and dissolved and particulate 137Cs in the river water was measured during 2014-2015, three years after the Tokyo Electric Power Corporation Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Annual fluxes of total (dissolved and particulate) 137Cs with considering desorption of 137Cs from riverine particles by change of salinity from the Tone River were similar in both years (78-107 × 109 Bq/y), indicating that about 0.03-0.06% of the estimated total amount of 137Cs deposited in the catchment (1.9-2.8 × 1014 Bq) was transported to the marine environment each year. Although the annual flux was about one order of magnitude lower than the daily direct discharge into the ocean from the FDNPP (800 × 109 Bq/y) during the corresponding period, continuous monitoring of rivers in the southern coastal area of east Japan on the North Pacific side are needed for the effect of 137Cs release via the rivers in the Kanto area over the long-term.
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Affiliation(s)
- Hyoe Takata
- Fukushima University, 1 Kanayagawa, Fukushima-city, Fukushima 960-1296, Japan; Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
| | - Naohiko Inatomi
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan
| | - Natsumi Kudo
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan
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14
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Suetake M, Nakano Y, Furuki G, Ikehara R, Komiya T, Kurihara E, Morooka K, Yamasaki S, Ohnuki T, Horie K, Takehara M, Law GTW, Bower W, Grambow B, Ewing RC, Utsunomiya S. Dissolution of radioactive, cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant in simulated lung fluid, pure-water, and seawater. CHEMOSPHERE 2019; 233:633-644. [PMID: 31195267 DOI: 10.1016/j.chemosphere.2019.05.248] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/25/2019] [Accepted: 05/27/2019] [Indexed: 06/09/2023]
Abstract
To understand the chemical durability of highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant in March 2011, we have, for the first time, performed systematic dissolution experiments with CsMPs isolated from Fukushima soils (one sample with 108 Bq and one sample with 57.8 Bq of 137Cs) using three types of solutions: simulated lung fluid, ultrapure water, and artificial sea water, at 25 and 37 °C for 1-63 days. The 137Cs was released rapidly within three days and then steady-state dissolution was achieved for each solution type. The steady-state 137Cs release rate at 25 °C was determined to be 4.7 × 103, 1.3 × 103, and 1. 3 × 103 Bq·m-2 s-1 for simulated lung fluid, ultrapure water, and artificial sea water, respectively. This indicates that the simulated lung fluid promotes the dissolution of CsMPs. The dissolution of CsMPs is similar to that of Si-based glass and is affected by the surface moisture conditions. In addition, the Cs release from the CsMPs is constrained by the rate-limiting dissolution of silicate matrix. Based on our results, CsMPs with ∼2 Bq, which can be potentially inhaled and deposited in the alveolar region, are completely dissolved after >35 years. Further, CsMPs could remain in the environment for several decades; as such, CsMPs are important factors contributing to the long-term impacts of radioactive Cs in the environment.
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Affiliation(s)
- Mizuki Suetake
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yuriko Nakano
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Genki Furuki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Ryohei Ikehara
- 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
| | - Eitaro Kurihara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, 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
| | - 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
| | - 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
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - William Bower
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, The University of Nantes, Nantes, 44307, France
| | - Rodney C Ewing
- Department of Geological 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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15
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Simonsen M, Lind OC, Saetra Ø, Isachsen PE, Teien HC, Albretsen J, Salbu B. Coastal transport of river-discharged radionuclides: Impact of speciation and transformation processes in numerical model simulations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 669:856-871. [PMID: 30897442 DOI: 10.1016/j.scitotenv.2019.01.434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
Following a potential nuclear accident, river run-off may potentially become a significant source of radionuclide contamination to the coastal marine environment. In the present work, code for radionuclide speciation and dynamic transfer of radionuclides between the different species was implemented in a Lagrangian marine dispersion model. A case study was performed where the model system utilized ocean circulation fields at relatively high spatial (160 m × 160 m in horizontal direction) and temporal resolution (1 hour), considering a hypothetical accident scenario including river discharges of 137Cs to the marine environment. Results from a number of simulations were compared to identify how factors associated with radionuclide speciation and transfer between the model compartments could affect the predicted radiocesium activity concentrations. The results showed that by including dynamic transfer of radionuclides between the model compartments, the total activity concentrations at far-field sites could vary with more than two orders of magnitude, demonstrating that this model configuration enables prediction of potential local hot-spots. However, the total activity concentration near the river outlets was less affected (< factor 10). The radionuclide speciation in the river discharges and the parameterization of 137Cs particle affinity greatly affected the specie distribution (> factor 103 increase in concentration of particle-associated 137Cs) as well as the settling of radionuclides towards the seabed (up to factor 102 increase in 137Cs sediment concentrations). These factors were therefore identified as important contributors to the overall uncertainty.
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Affiliation(s)
- Magne Simonsen
- Norwegian Meteorological Institute, P.O. Box 43, Blindern, Oslo NO-0313, Norway; Centre of Environmental Radioactivity CoE, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, NO-1433 Ås, Norway.
| | - Ole Christian Lind
- Centre of Environmental Radioactivity CoE, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, NO-1433 Ås, Norway
| | - Øyvind Saetra
- Norwegian Meteorological Institute, P.O. Box 43, Blindern, Oslo NO-0313, Norway
| | - Pål Erik Isachsen
- Norwegian Meteorological Institute, P.O. Box 43, Blindern, Oslo NO-0313, Norway; Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, NO-0316 Oslo, Norway
| | - Hans-Christian Teien
- Centre of Environmental Radioactivity CoE, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, NO-1433 Ås, Norway
| | - Jon Albretsen
- Institute of Marine Research, P.O. Box 1870 Nordnes, Bergen NO-5817, Norway
| | - Brit Salbu
- Centre of Environmental Radioactivity CoE, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, NO-1433 Ås, Norway
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16
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Park SM, Alessi DS, Baek K. Selective adsorption and irreversible fixation behavior of cesium onto 2:1 layered clay mineral: A mini review. JOURNAL OF HAZARDOUS MATERIALS 2019; 369:569-576. [PMID: 30818121 DOI: 10.1016/j.jhazmat.2019.02.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/19/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
In this study, we reviewed the selective adsorption and irreversible fixation of cesium (Cs+) on clay minerals. The selective adsorption of Cs+ results from reactions with frayed edge sites (FES) of clay minerals. The content of FES is about 0.1-2.0% of the total cation exchange capacity (CEC). The fractionation of Cs+ in actual accident sites mainly exists as a residue, which is important because it is closely related to the strong binding between Cs+ and soils. Cs+ adsorbed onto FES can move into the deeper interlayer via weathering processes, thereby Cs+ can be irreversibly fixed in the interlayer of non-expanding 2:1 layered clay mineral. Additionally, Cs+ can be adsorbed in the interlayer of the expanding clay mineral and can be fixed by interlayer collapse. For this reason, Cs+ adsorption onto FES is defined as 'selective adsorption' subsequent sorption in the interlayer as 'irreversible fixation'. Furthermore, the extended X-ray absorption fine structure (EXAFS) analysis can confirm that Cs+ bound to illite is coordinated with the outer surface (OOS) and interlayer surface oxygens (OIS) through FES or interlayer sites. Through these processes, Cs+ is adsorbed selectively onto FES, while Cs+ can subsequently move into the interlayer and become more strongly fixed.
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Affiliation(s)
- Sang-Min Park
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 561-756, Republic of Korea
| | - Daniel S Alessi
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Kitae Baek
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 561-756, Republic of Korea.
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17
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Park SM, Yang JS, Tsang DCW, Alessi DS, Baek K. Enhanced irreversible fixation of cesium by wetting and drying cycles in soil. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2019; 41:149-157. [PMID: 30143907 DOI: 10.1007/s10653-018-0174-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 08/15/2018] [Indexed: 06/08/2023]
Abstract
The retention of radioactive cesium (Cs) in soil is significantly related to the types of clay minerals, while the weathering process affects the irreversible adsorption sites in clay minerals. In this study, the effect of weathering (exposure duration of Cs and repeated wetting and drying cycles) on fractionation of Cs in soils was investigated using fractionation analysis by the sequential extraction. The residual fraction of Cs increased slowly with exposure time but increased rapidly by repeated wetting and drying cycles. XRD analysis shows that a 1.43 nm of interlayer size for vermiculite is shortened to 1.00 nm, i.e., similar to that of illite. The change implies the potential that the structure of expandable clay minerals is transformed to the non-expandable structure by weathering process after Cs retention. Based on the result, the residual fraction of Cs, most stable form of Cs in the soil, reached relatively rapidly to a maximum. However, the process is much slower kinetically in the field because the bench-scale weathering process used in this study is more aggressive. This study implies that Cs fractionations in the soil are converted into a more stable fraction by weathering processes in the soil. Therefore, Cs removal should be conducted as soon as possible after accidental release of Cs in an environmental side.
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Affiliation(s)
- Sang-Min Park
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 54896, Republic of Korea
| | - Jung-Seok Yang
- Systems Biotechnology Research Center, KIST Gangneung Institute of Natural Products, 679 Saimdang-ro, Gangneung-si, Gangwon-do, 25451, Republic of Korea
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Daniel S Alessi
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Kitae Baek
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 54896, Republic of Korea.
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18
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Somboon S, Kavasi N, Sahoo SK, Inoue K, Arae H, Tsuruoka H, Shimizu H, Fukushi M. Radiocesium and 40K distribution of river sediments and floodplain deposits in the Fukushima exclusion zone. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 195:40-53. [PMID: 30243099 DOI: 10.1016/j.jenvrad.2018.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 06/08/2023]
Abstract
In this study, radiocesium and 40K analysis were accomplished for samples of riverbed sediments and floodplain deposits collected from five rivers in the vicinity (<20 km) of the damaged Fukushima Daiichi Nuclear Power Plant after seven years of the accident. Sediment particle size distribution and major oxide content were determined also for six selected samples to understand the retention and migration process of radiocesium in river environments. The radiocesium activity concentration varied from 103 ± 6 Bq·kg-1 to 22,000 ± 500 Bq·kg-1 in riverbed sediments and from 92 ± 5 Bq·kg-1 to 117,000 ± 2000 Bq·kg-1 in floodplain deposits. The 134Cs/137Cs ratio (decay corrected to 15 March 2011) was 1.02 in the both samples. Compared to monitoring results in 2011, it was proved that the radiocesium distribution pattern had been changed remarkably during seven years. The radiocesium was primarily attached to fine clay particles but its sorption on sand and coarse sand particles was also considerable. The sorption process of radiocesium was not affected by the presence of water and moreover, after seven years of the Fukushima accident, a significant radiocesium migration cannot be expected without particle migration. Consequently, radiocesium will remain for a long time in the river environments and its redistribution is mainly affected by the erosion process of the sediments. The average 40K activity concentration of riverbed sediment and floodplain deposit samples was 640 ± 152 Bq·kg-1 changing from 319 ± 18 Bq·kg-1 to 916 ± 41 Bq·kg-1. In the river estuary zones, significant activity concentration decrements were observed for both radionuclides. This suggests that seawater intrusion has a decreasing effect on both natural and artificial radionuclides via wash-out of particulate radiocesium and 40K, and desorption of these radionuclides, but to reveal the detail of this process further investigations are required. The analysis of 40K can help in a simple and easy way to reveal the mineral composition differences of sediment samples.
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Affiliation(s)
- S Somboon
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan; National Institutes for Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences, 4-9-1Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - N Kavasi
- National Institutes for Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences, 4-9-1Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - S K Sahoo
- National Institutes for Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences, 4-9-1Anagawa, Inage-ku, Chiba, 263-8555, Japan.
| | - K Inoue
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
| | - H Arae
- National Institutes for Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences, 4-9-1Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - H Tsuruoka
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
| | - H Shimizu
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
| | - M Fukushi
- Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan
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Mukai H, Tamura K, Kikuchi R, Takahashi Y, Yaita T, Kogure T. Cesium desorption behavior of weathered biotite in Fukushima considering the actual radioactive contamination level of soils. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 190-191:81-88. [PMID: 29775841 DOI: 10.1016/j.jenvrad.2018.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/11/2018] [Accepted: 05/05/2018] [Indexed: 06/08/2023]
Abstract
For the better understanding of radioactive contamination in Fukushima Prefecture at present and in future, Cs desorption experiments have been conducted mainly using weathered biotite (WB) collected from Fukushima Prefecture and considering the actual contamination level (∼10-10 wt%) of radiocesium in Fukushima Prefecture. In the experiments, 137Cs sorbed to WB by immersing in 137Cs solution for one day was mostly desorbed by solutions of 1 M NaNO3, 1 M LiNO3, 10-1 M HCl, and 10-1 M HNO3, although it was barely desorbed by 1 M KNO3, 1 M CsNO3, 1 M NH4NO3, and natural seawater. X-ray diffraction analysis of WB after immersing in these solutions suggested that the collapse of the hydrated interlayers in WB suppressed the desorption of Cs. On the other hand, 137Cs was barely desorbed from WB even by the treatments with solutions of NaNO3 and LiNO3 if the duration for the sorption was longer than approximately two weeks, as well as radioactive WB collected from actual contaminated soils in Fukushima Prefecture. This result implies that Cs sorbed in WB became more strongly fixed with time. Probably removal of radiocesium sorbed in weathered granitic soil at Fukushima Prefecture is difficult by any electrolyte solutions, as more than seven years have passed since the accident.
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Affiliation(s)
- Hiroki Mukai
- Department of Earth and Planetary Science, Graduate School of Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567, Japan.
| | - Kenji Tamura
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Ryosuke Kikuchi
- Department of Earth and Planetary Science, Graduate School of Sciences, 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 Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tsuyoshi Yaita
- Quantum Beam Science Center and Fukushima Environmental Safety Center, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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20
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Ikehara R, Suetake M, Komiya T, Furuki G, Ochiai A, Yamasaki S, Bower WR, Law GTW, Ohnuki T, Grambow B, Ewing RC, Utsunomiya S. Novel Method of Quantifying Radioactive Cesium-Rich Microparticles (CsMPs) in the Environment from the Fukushima Daiichi Nuclear Power Plant. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:6390-6398. [PMID: 29782160 DOI: 10.1021/acs.est.7b06693] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Highly radioactive cesium-rich microparticles (CsMPs) were released from the Fukushima Daiichi nuclear power plant (FDNPP) to the surrounding environment at an early stage of the nuclear disaster in March of 2011; however, the quantity of released CsMPs remains undetermined. Here, we report a novel method to quantify the number of CsMPs in surface soils at or around Fukushima and the fraction of radioactivity they contribute, which we call "quantification of CsMPs" (QCP) and is based on autoradiography. Here, photostimulated luminescence (PSL) is linearly correlated to the radioactivity of various microparticles, with a regression coefficient of 0.0523 becquerel/PSL/h (Bq/PSL/h). In soil collected from Nagadoro, Fukushima, Japan, CsMPs were detected in soil sieved with a 114 μm mesh. There was no overlap between the radioactivities of CsMPs and clay particles adsorbing Cs. Based on the distribution of radioactivity of CsMPs, the threshold radioactivity of CsMPs in the size fraction of <114 μm was determined to be 0.06 Bq. Based on this method, the number and radioactivity fraction of CsMPs in four surface soils collected from the vicinity of the FDNPP were determined to be 48-318 particles per gram and 8.53-31.8%, respectively. The QCP method is applicable to soils with a total radioactivity as high as ∼106 Bq/kg. This novel method is critically important and can be used to quantitatively understand the distribution and migration of the highly radioactive CsMPs in near-surface environments surrounding Fukushima.
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Affiliation(s)
- Ryohei Ikehara
- Department of Chemistry , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Mizuki Suetake
- 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
| | - Genki Furuki
- Department of Chemistry , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Asumi Ochiai
- Department of Chemistry , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , 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
| | - William R Bower
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Oxford Road , Manchester , M13 9PL United Kingdom
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Oxford Road , Manchester , M13 9PL United Kingdom
| | - 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
| | - Rodney C Ewing
- Department of Geological Sciences and Center for International Security and Cooperation , Stanford University , Stanford , California 94305-2115 , United States
| | - Satoshi Utsunomiya
- Department of Chemistry , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
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21
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Inoue M, Yoneoka S, Ochiai S, Morokado T, Uemura H, Nagao S. Low levels of 134Cs in suspended solids in rivers discharging into the Sea of Japan. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5783-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Yamazaki H, Ishida M, Hinokio R, Yamashiki YA, Azuma R. Spatiotemporal distribution and fluctuation of radiocesium in Tokyo Bay in the five years following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. PLoS One 2018; 13:e0193414. [PMID: 29494667 PMCID: PMC5832246 DOI: 10.1371/journal.pone.0193414] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/10/2018] [Indexed: 11/19/2022] Open
Abstract
A monitoring survey was conducted from August 2011 to July 2016 of the spatiotemporal distribution in the 400 km2 area of the northern part of Tokyo Bay and in rivers flowing into it of radiocesium released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The average inventory in the river mouth (10 km2) was 131 kBq⋅m-2 and 0.73 kBq⋅m-2 in the central bay (330 km2) as the decay corrected value on March 16, 2011. Most of the radiocesium that flowed into Tokyo Bay originated in the northeastern section of the Tokyo metropolitan area, where the highest precipitation zone of 137Cs in soil was almost the same level as that in Fukushima City, then flowed into and was deposited in the Old-Edogawa River estuary, deep in Tokyo Bay. The highest precipitation of radiocesium measured in the high contaminated zone was 460 kBq⋅m-2. The inventory in sediment off the estuary of Old-Edogawa was 20.1 kBq⋅m-2 in August 2011 immediately after the accident, but it increased to 104 kBq⋅m-2 in July 2016. However, the radiocesium diffused minimally in sediments in the central area of Tokyo Bay in the five years following the FDNPP accident. The flux of radiocesium off the estuary decreased slightly immediately after the accident and conformed almost exactly to the values predicted based on its radioactive decay. Contrarily, the inventory of radiocesium in the sediment has increased. It was estimated that of the 8.33 TBq precipitated from the atmosphere in the catchment regions of the rivers Edogawa and Old-Edogawa, 1.31 TBq migrated through rivers and was deposited in the sediments of the Old-Edogawa estuary by July 2016. Currently, 0.25 TBq⋅yr-1 of radiocesium continues to flow into the deep parts of Tokyo Bay.
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Affiliation(s)
- Hideo Yamazaki
- Graduate School of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Masanobu Ishida
- Graduate School of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
- * E-mail:
| | - Ryoichi Hinokio
- Faculty of Science and Technology, Ryukoku University, Otsu, Shiga, Japan
| | - Yosuke Alexandre Yamashiki
- Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Kyoto, Japan
| | - Ryokei Azuma
- Department of Civil Engineering and Urban Design, Osaka Institute of Technology, Osaka, Osaka, Japan
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23
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Sakuma K, Malins A, Funaki H, Kurikami H, Niizato T, Nakanishi T, Mori K, Tada K, Kobayashi T, Kitamura A, Hosomi M. Evaluation of sediment and 137Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modeling. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 182:44-51. [PMID: 29190508 DOI: 10.1016/j.jenvrad.2017.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/23/2017] [Accepted: 11/21/2017] [Indexed: 06/07/2023]
Abstract
The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant and covers 7.7 km2. Parts of the catchment were decontaminated between fall 2012 and March 2014 in preparation for the return of the evacuated population. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and 137Cs redistribution within the catchment, including the effect of decontamination on redistribution. Fine resolution grid cells were used to model local features of the catchment, such as paddy fields adjacent to the Oginosawa River. The simulation was verified using monitoring data for river water discharge rates (r = 0.92), suspended sediment concentrations, and particulate 137Cs concentrations (r = 0.40). Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies, e.g. the paddy fields in the Ogi and Kainosaka districts, as the ground in these areas saturates during heavy rain and is easily eroded. A discrepancy between the simulation and monitoring results on the sediment discharge rate following decontamination may be explained by fast erosion occurring after decontamination. Forested areas far from the channels only made a minor contribution to 137Cs input to watercourses, total erosion of between 0.001 and 0.1 mm from May 2011 to December 2015, as ground saturation is infrequent in these areas. The 2.3-6.9% y-1 decrease in the amount of 137Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y-1), along with a migration downwards into subsoil and a small amount of export. The amount of 137Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas by the end of 2015. However continued monitoring of 137Cs concentrations in river water over future years is advised, as recultivation of paddy fields by returnees may again lead to fast erosion rates and release of the remaining inventory.
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Affiliation(s)
- Kazuyuki Sakuma
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Alex Malins
- Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Hironori Funaki
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Hiroshi Kurikami
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Tadafumi Niizato
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Takahiro Nakanishi
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan
| | - Koji Mori
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Kazuhiro Tada
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Takamaru Kobayashi
- Geosphere Environmental Technology Corporation, 2-1 Kanda-Awajicho, Chiyoda-ku, Tokyo 101-0063, Japan
| | - Akihiro Kitamura
- Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Fukushima 963-7700, Japan; Center for Computational Science & e-Systems, Japan Atomic Energy Agency, University of Tokyo Kashiwanoha Campus Satellite, 178-4-4 Wakashiba, Kashiwa-shi, Chiba 277-0871, Japan
| | - Masaaki Hosomi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan
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Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan. Proc Natl Acad Sci U S A 2017; 114:11092-11096. [PMID: 28973919 DOI: 10.1073/pnas.1708659114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There are 440 operational nuclear reactors in the world, with approximately one-half situated along the coastline. This includes the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which experienced multiple reactor meltdowns in March 2011 followed by the release of radioactivity to the marine environment. While surface inputs to the ocean via atmospheric deposition and rivers are usually well monitored after a nuclear accident, no study has focused on subterranean pathways. During our study period, we found the highest cesium-137 (137Cs) levels (up to 23,000 Bq⋅m-3) outside of the FDNPP site not in the ocean, rivers, or potable groundwater, but in groundwater beneath sand beaches over tens of kilometers away from the FDNPP. Here, we present evidence of a previously unknown, ongoing source of Fukushima-derived 137Cs to the coastal ocean. We postulate that these beach sands were contaminated in 2011 through wave- and tide-driven exchange and sorption of highly radioactive Cs from seawater. Subsequent desorption of 137Cs and fluid exchange from the beach sands was quantified using naturally occurring radium isotopes. This estimated ocean 137Cs source (0.6 TBq⋅y-1) is of similar magnitude as the ongoing releases of 137Cs from the FDNPP site for 2013-2016, as well as the input of Fukushima-derived dissolved 137Cs via rivers. Although this ongoing source is not at present a public health issue for Japan, the release of Cs of this type and scale needs to be considered in nuclear power plant monitoring and scenarios involving future accidents.
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Kambayashi S, Zhang J, Narita H. Spatial assessment of radiocaesium in the largest lagoon in Fukushima after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident. MARINE POLLUTION BULLETIN 2017; 122:344-352. [PMID: 28688521 DOI: 10.1016/j.marpolbul.2017.06.071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
Radionuclides deposited on land by global fallouts and nuclear power station accidents spread over coastal environments through estuarine areas connecting land to ocean. In this study, we monitored activity concentration of radiocaesium in surface sediment and re-suspended particles in Matsukawa-ura lagoon, the largest lagoon in Fukushima, after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident. Radiocaesium distribution in surface sediment varied spatiotemporally and irregularly due to the effect of tidal waves. The effective half-life was significantly shorter than physical half-life, suggesting some system of radiocaesium discharge in the lagoon. Sediment trap observation revealed re-suspended particles from sediment were transported to the ocean. For these reasons, it is suggested that re-suspension of particles in the lagoon and their transportation to the ocean by the seawater exchange process are important processes of radiocaesium discharge. Moreover, our results show that seawater exchange process contributes to the dispersion of radiocaesium in the ocean.
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Affiliation(s)
- Shota Kambayashi
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Jing Zhang
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
| | - Hisashi Narita
- School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu-ku, Shizuoka 424-8610, Japan
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26
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Imoto J, Ochiai A, Furuki G, Suetake M, Ikehara R, Horie K, Takehara M, Yamasaki S, Nanba K, Ohnuki T, Law GTW, Grambow B, Ewing RC, Utsunomiya S. Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant. Sci Rep 2017; 7:5409. [PMID: 28710475 PMCID: PMC5511200 DOI: 10.1038/s41598-017-05910-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/05/2017] [Indexed: 11/09/2022] Open
Abstract
Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79–780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs’ origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi2O6 · nH2O, CsMPs are comprised mainly of Zn–Fe-oxide nanoparticles in a SiO2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn–Fe-oxide). The 235U/238U values in two CsMPs: 0.030 (±0.005) and 0.029 (±0.003), are consistent with that of enriched nuclear fuel. The values are higher than the average burnup estimated by the ORIGEN code and lower than non-irradiated fuel, suggesting non-uniform volatilization of U from melted fuels with different levels of burnup, followed by sorption onto Zn–Fe-oxides. The nano-scale texture and isotopic analyses provide a partial record of the chemical reactions that occurred in the fuel during meltdown. Also, the CsMPs were an important medium of transport for the released radionuclides in a respirable form.
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Affiliation(s)
- Junpei Imoto
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka, 819-0395, Japan
| | - Asumi Ochiai
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka, 819-0395, Japan
| | - Genki Furuki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka, 819-0395, Japan
| | - Mizuki Suetake
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka, 819-0395, Japan
| | - Ryohei Ikehara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, 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
| | - Kenji Nanba
- Department of Environment System Management, Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima, 960-1296, 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
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, the University of Nantes CNRS/IN2P3, Nantes, 44307, France
| | - Rodney C Ewing
- Department of Geological 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-shi, Fukuoka, 819-0395, Japan.
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