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Zhu J, Hao Y, Chen C, Wang T, Chen K, Zhang L, Zhang A, Xie T, Zhang Q. Transformation and environmental risk of 90Sr and 137Cs under extreme rainstorm at a proposed nuclear facility site in China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 278:107498. [PMID: 39013308 DOI: 10.1016/j.jenvrad.2024.107498] [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: 04/09/2024] [Revised: 07/07/2024] [Accepted: 07/09/2024] [Indexed: 07/18/2024]
Abstract
This paper explores the environmental hazards associated with nuclear facilities in arid regions, focusing on the rapid migration of radionuclides facilitated by flood runoff resulting from extreme rainstorms. Through a case study of a proposed nuclear facility site in China, the study developed a comprehensive model to calculate the transformation of 90Sr and 137Cs in flood and subsurface water during accidents. The methodology employs a combination of field tests, radionuclide adsorption tests, the SWAT model, and the HGS model to create a fully integrated model. This approach allows for the several complex couplings (radionuclide-flood runoff-subsurface water) that have not been previously examined in the reactive solute transport. The findings reveal that despite groundwater movement being relatively sluggish, 90Sr and 137Cs migrate downstream rapidly due to their transportation by floods, which permeate the Upper Pleistocene gravel aquifer along the route. The study underscores the importance of considering the migration of radionuclides carried by floods generated by extreme rainstorms, as it poses a significant risk that cannot be ignored.
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Affiliation(s)
- Jun Zhu
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China; Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
| | - Ying Hao
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
| | - Chao Chen
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
| | - Ting Wang
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
| | - Ke Chen
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Linlin Zhang
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Aiming Zhang
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China
| | - Tian Xie
- Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, China Institute for Radiation Protection, Taiyuan, 030006, China; College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China.
| | - Qiulan Zhang
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China.
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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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3
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Tsuji H, Nishikiori T, Ito S, Ozaki H, Watanabe M, Sakai M, Ishii Y, Hayashi S. Influential factors of long-term and seasonal 137Cs change in agricultural and forested rivers: Temperature, water quality and an intense Typhoon Event. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 338:122617. [PMID: 37757931 DOI: 10.1016/j.envpol.2023.122617] [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: 06/16/2023] [Revised: 09/09/2023] [Accepted: 09/23/2023] [Indexed: 09/29/2023]
Abstract
In this study, the effect of temperature, water quality, and the impact of an intense typhoon event on change in 137Cs concentration in the water of agricultural and forested rivers near the Fukushima Daiichi nuclear power plant (Japan) was evaluated using monthly stationary observations obtained under baseflow conditions 2.8-10.6 years after the nuclear accident in 2011. The dissolved 137Cs concentration fluctuated seasonally with water temperature in all rivers, and the increase in dissolved 137Cs concentration for unit increase in temperature was higher in forested rivers than in agricultural rivers. The relationship between water temperature and the apparent distribution coefficient of 137Cs well followed the van 't Hoff equation in the two agricultural rivers, where the enthalpy of reaction was estimated as -15.6 and -19.6 kJ mol-1. The van 't Hoff equation was not well followed for a forested river, where the suspended solids mainly comprised organic matter, suggesting that the dominant process determining dissolved 137Cs concentrations in forested rivers is not only water temperature effect on ion exchange, but rather the input of 137Cs and K+ (competing with 137Cs for exchange sites on mineral particles) into the water phase via litter leaching. Suspended solids concentrations in agricultural rivers correlated negatively with 137Cs concentrations in suspended solids, suggesting an increased proportion of coarse particles or the input of soils with low 137Cs concentration from decontaminated agricultural land. At some sites, 137Cs concentrations in dissolved form and in suspended solids were reduced sharply in association with the passage of Typhoon Hagibis in October 2019, suggesting that Typhoon Hagibis caused large-scale surface erosion that removed the source of 137Cs.
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Affiliation(s)
- Hideki Tsuji
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, 10-2, Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
| | - Tatsuhiro Nishikiori
- Agricultural Radiation Research Center, Tohoku Agriculture Research Center, National Agriculture and Food Research Organization, 50 Harajukuminami, Arai, Fukushima, Fukushima, 960-2156, Japan.
| | - Shoko Ito
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, 10-2, Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
| | - Hirokazu Ozaki
- Tokyo University of Agriculture and Technology, 3-5-8, Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan.
| | - Mirai Watanabe
- National Institute for Environmental Studies, Regional Environment Conservation Division, 16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
| | - Masaru Sakai
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, 10-2, Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
| | - Yumiko Ishii
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, 10-2, Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
| | - Seiji Hayashi
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, 10-2, Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
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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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Hirose K, Povinec PP. Ten years of investigations of Fukushima radionuclides in the environment: A review on process studies in environmental compartments. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106929. [PMID: 35717792 DOI: 10.1016/j.jenvrad.2022.106929] [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: 03/16/2022] [Revised: 05/15/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
In March 2011, severe nuclear accident happened at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) after the gigantic earthquake and following huge tsunami wave. A lot of investigations to assess environmental and radiological impacts of released radionuclides have been conducted by domestic and international organizations. Environmental radioactivity research related to the FDNPP accident has spread widely over different scientific fields due to specific features of the accident, and specifically its impact on the marine environment. The present paper summarizes major lessons learned from the environmental investigations of the FDNPP accident. Environmental radioactivity studies have typical interdisciplinary character; especially physics and chemistry are fundamental as a base of process studies in the environment. In this sight, we review chemical aspects regarding FDNPP-derived radiocesium transfer within and between compartments (atmosphere, ocean and land). We also discuss future trends in investigations of behavior of anthropogenic radionuclides in the environment, important not only for a better understanding of impacts of the FDNPP accident on the environment, but also for improving our general knowledge of the total environment in the Anthropocene era and its protection for the future.
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Affiliation(s)
- Katsumi Hirose
- Laboratory for Environmental Research at Mount Fuji, Okubo, Shinjyuku, Tokyo, Japan.
| | - Pavel P Povinec
- Comenius University, Department of Nuclear Physics and Biophysics, Bratislava, Slovakia.
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Konoplev A. Fukushima and Chernobyl: Similarities and Differences of Radiocesium Behavior in the Soil-Water Environment. TOXICS 2022; 10:toxics10100578. [PMID: 36287858 PMCID: PMC9608664 DOI: 10.3390/toxics10100578] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/30/2022] [Accepted: 09/24/2022] [Indexed: 05/29/2023]
Abstract
In the wake of Chernobyl and Fukushima accidents, radiocesium has become a radionuclide of most environmental concern. The ease with which this radionuclide moves through the environment and is taken up by plants and animals is governed by its chemical forms and site-specific environmental characteristics. Distinctions in climate and geomorphology, as well as 137Cs speciation in the fallout, result in differences in the migration rates of 137Cs in the environment and rates of its natural attenuation. In Fukushima areas, 137Cs was strongly bound to soil and sediment particles, with its bioavailability being reduced as a result. Up to 80% of the deposited 137Cs on the soil was reported to be incorporated in hot glassy particles (CsMPs) insoluble in water. Disintegration of these particles in the environment is much slower than that of Chernobyl-derived fuel particles. The higher annual precipitation and steep slopes in Fukushima-contaminated areas are conducive to higher erosion and higher total radiocesium wash-off. Among the common features in the 137Cs behavior in Chernobyl and Fukushima are a slow decrease in the 137Cs activity concentration in small, closed, and semi-closed lakes and its particular seasonal variations: increase in the summer and decrease in the winter.
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Affiliation(s)
- Alexei Konoplev
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan
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Niida T, Wakiyama Y, Takata H, Taniguchi K, Kurosawa H, Fujita K, Konoplev A. A comparative study of riverine 137Cs dynamics during high-flow events at three contaminated river catchments in Fukushima. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 821:153408. [PMID: 35090916 DOI: 10.1016/j.scitotenv.2022.153408] [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: 11/09/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
This study presents the temporal variations in riverine 137Cs concentrations and fluxes to the ocean during high-flow events in three coastal river catchments contaminated by the Fukushima Daiichi Nuclear Power Plant accident. River water samples were collected at points downstream in the Niida, Ukedo, and Takase Rivers during three high-flow events that occurred in 2019-2020. Variations in both the dissolved and particulate 137Cs concentrations appeared to reflect the spatial pattern of the 137Cs inventory in the catchments, rather than variations in physico-chemical properties of water and suspended solid. Negative relationships between the 137Cs concentration and δ15N in suspended solid were found in all rivers during the intense rainfall events, suggesting an increased contribution of sediment from forested areas to the elevation of particulate 137Cs concentration. The 137Cs flux ranged from 0.33 to 19 GBq, depending on the rainfall erosivity. The particulate 137Cs fluxes from the Ukedo River were relatively low compared with the other two rivers and were attributed to the effect of the Ogaki Dam reservoir upstream. The percentage of 137Cs desorbed in seawater relative to 137Cs in suspended solids ranged from 2.8% to 6.6% and tended to be higher with a higher fraction of exchangeable 137Cs. The estimated potential release of 137Cs desorbed from suspended solids to the ocean was 0.022-0.57 GBq, and its ratio to the direct flux of dissolved 137Cs was 0.12-6.2. Episodic sampling during high-flow events demonstrated that the particulate 137Cs flux depends on catchment characteristics and controls 137Cs transfer to the ocean.
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Affiliation(s)
| | | | - Hyoe Takata
- Institute of Environmental Radioactivity, Fukushima University, Japan
| | | | - Honoka Kurosawa
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University, Japan
| | - Kazuki Fujita
- Fukushima Prefectural Centre for Environmental Creation, Japan
| | - Alexei Konoplev
- Institute of Environmental Radioactivity, Fukushima University, Japan
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Konoplev A, Wakiyama Y, Wada T, Ivanov M, Komissarov M, Nanba K. Reconstruction of time changes in radiocesium concentrations in the river of the Fukushima Dai-ichi NPP contaminated area based on its depth distribution in dam reservoir's bottom sediments. ENVIRONMENTAL RESEARCH 2022; 206:112307. [PMID: 34756914 DOI: 10.1016/j.envres.2021.112307] [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: 07/04/2021] [Revised: 09/20/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Radionuclide depth distribution in bottom sediments in deep-water zones of dam reservoirs, where no sediment mixing occurs, can be used to reconstruct time changes in particulate activity concentrations of radionuclides strongly bound to bottom sediments. This approach was used to analyze the 137Cs concentration profile in a bottom sediment core collected from Ogaki dam reservoir on the Ukedo River in the Fukushima Dai-ichi nuclear power plant contaminated zone in October 2019. The derived 137Cs particulate concentrations provided a basis for estimating the dissolved concentration and its temporal trend in the Ukedo River, using the mean value of the apparent 137Cs distribution coefficient. The reconstructed particulate and dissolved 137Cs concentrations and their temporal trends are consistent with monitoring data. The annual mean particulate and dissolved 137Cs wash-off ratios were also calculated for the period of eight years after the accident. Interestingly, the particulate 137Cs wash-off ratios for the Ukedo River at Ogaki dam were found to be similar to those for the Pripyat River at Chernobyl in the same time period after the accident, while the dissolved 137Cs wash-off ratios in the Ukedo River were an order of magnitude lower than the corresponding values in the Pripyat River. Both the particulate and dissolved 137Cs wash-off ratios in the Ukedo River declined faster during the first eight years after the FDNPP accident than predicted by the diffusional model, most likely, due to greater natural attenuation and, to some extent, remediation measures implemented on the catchments in Fukushima.
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Affiliation(s)
- Alexei Konoplev
- Institute of Environmental Radioactivity, Fukushima University, Kanayagawa 1, Fukushima, 960-1296, Japan.
| | - Yoshifumi Wakiyama
- Institute of Environmental Radioactivity, Fukushima University, Kanayagawa 1, Fukushima, 960-1296, Japan
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, Kanayagawa 1, Fukushima, 960-1296, Japan
| | - Maxim Ivanov
- Faculty of Geography, Moscow State University, Moscow, 119991, Russia; Institute of Geography, Russian Academy of Science, Russia
| | | | - Kenji Nanba
- Institute of Environmental Radioactivity, Fukushima University, Kanayagawa 1, Fukushima, 960-1296, Japan
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INOSE S, NAGAI Y, HONDA T, KOIKE Y. Investigation of Environmental Dynamics of Radioactive Cesium Based on the Analysis of Organic Composition in Sediments Sampled at the Nogawa River in the Tama River System. BUNSEKI KAGAKU 2022. [DOI: 10.2116/bunsekikagaku.71.269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Satoshi INOSE
- Graduate School of Science and Technology, Meiji University
| | - Yoshitaka NAGAI
- Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University
| | | | - Yuya KOIKE
- School of Science and Technology, Meiji University
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Takata H, Wada T, Aono T, Inoue M, Kanasashi T, Suzuki S, Amano Y. Factors controlling dissolved 137Cs activities in coastal waters on the eastern and western sides of Honshu, Japan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151216. [PMID: 34717992 DOI: 10.1016/j.scitotenv.2021.151216] [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: 08/31/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
The distributions of dissolved 137Cs in river, nearshore, and offshore waters on the east and west coasts of the Japanese island of Honshu were studied in 2018-2021, 7-10 years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. On the east side along the north western North Pacific (Fukushima Prefecture), estuarine processes, including desorption from riverine particles and dissolution into pore water from riverine particles that had settled to the seafloor, contributed to the maintenance of high dissolved 137Cs activities in nearshore and offshore waters. A survey and mass-balance calculation in a semi-enclosed estuarine area, the Matsukawa-ura, in the northern part of Fukushima, provided convincing evidence that rivers contributed to the influx of 137Cs to coastal waters. In contrast, the extremely low activities of dissolved and particulate 137Cs in the Tedori River of Ishikawa Prefecture on the western side of Japan along the Japan Sea suggested that inputs of riverine 137Cs made a negligible contribution to the increase of dissolved 137Cs activities in the nearshore and offshore waters. The relatively high dissolved 137Cs activities observed in the offshore waters of the Japan Sea were due to movement of FDNPP-derived 137Cs into the Japan Sea via the Tsushima Warm Current. Mechanisms controlling the distributions of 137Cs activities in coastal waters of the eastern and western sides of Japan therefore differ.
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Affiliation(s)
- Hyoe Takata
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan.
| | - Toshihiro Wada
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan
| | - Tatsuo Aono
- National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, Fukushima, Fukushima 960-1295, Japan
| | - Mutsuo Inoue
- Low Level Radioactivity Laboratory, Kanazawa University, Nomi, Ishikawa 923-1224, Japan
| | - Tsutomu Kanasashi
- Institute of Environmental Radioactivity, Fukushima University, Fukushima, Fukushima 960-1296, Japan
| | - Shotaro Suzuki
- Fukushima Prefectural Fisheries and Marine Science Research Center, Iwaki, Fukushima 970-0316, Japan
| | - Yosuke Amano
- Fukushima Prefectural Fisheries and Marine Science Research Center, Iwaki, Fukushima 970-0316, Japan
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