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Hirose K. Review of the sources and behaviors of plutonium isotopes in the atmosphere and ocean. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 277:107466. [PMID: 38838510 DOI: 10.1016/j.jenvrad.2024.107466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024]
Abstract
Plutonium, as well as fission products such as 137Cs, had been released into the earth environment in 1945 after the first atmospheric nuclear explosion of plutonium bomb in the desert of New Mexico (USA, July 16) and later over Nagasaki (August 9), followed then by many other explosions. Thus, plutonium cycling in the atmosphere and ocean has become a major public concern as a result of the radiological and chemical toxicity of plutonium. However, plutonium isotopes and 137Cs are important transient tracers of biogeochemical and physical processes in the environment, respectively. In this review, we show that both physical and chemical approaches are needed to comprehensively understand the behaviors of plutonium in the atmosphere and ocean. In the atmosphere, plutonium and 137Cs attach with aerosols; thus, plutonium moves according to physical and chemical processes in connection with aerosols; however, since plutonium is a chemically reactive element, its behavior in an aqueous environment is more complicated, because biogeochemical regulatory factors, in addition to geophysical regulatory factors, must be considered. Meanwhile, 137Cs is chemically inert in aqueous environments. Therefore, the biogeochemical characteristics of plutonium can be elucidated through a comparison with those of 137Cs, which show conservative properties and moves according to physical processes. Finally, we suggest that monitoring of both plutonium and 137Cs can help elucidate geophysical and biogeochemical changes from climate changes.
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Affiliation(s)
- Katsumi Hirose
- Laboratory for Environmental Research at Mount Fuji, Okubo Shinjyuku-ku, Tokyo, Japan.
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2
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Wei X, Zhang R, Zhu J, Wang S, Guan Y, Li G, Yin Y, Liu Z. Spatial distribution and modelling of 239+240Pu in the sediments and seawater columns of the South China Sea and Indian Ocean. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 343:123244. [PMID: 38154779 DOI: 10.1016/j.envpol.2023.123244] [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: 10/31/2023] [Revised: 12/10/2023] [Accepted: 12/25/2023] [Indexed: 12/30/2023]
Abstract
In order to investigate the 239+240Pu potential influence in the ocean, and develop a new method for rapidly monitoring radioactive pollution, the 239+240Pu spatial distribution in the South China Sea (SCS) and the Indian Ocean (IND) sediments is analyzed by SF-ICP-MS (ELEMENT 2). The inventory-weighted mean activities of 239+240Pu were 0.413 ± 0.333 mBq/g, 0.128 ± 0.044 mBq/g, and 0.483 ± 0.606 mBq/g in the sediments of the SCS, eastern IND, and Arabian Sea, respectively. The 239+240Pu activity spatial distribution in the SCS sediments was influenced by the current, the vertical distribution of Pu in seawater, and the transport of particulate matter. The 239+240Pu activity spatial distribution in the IND sediments could be impacted by Antarctic Intermediate Water. The average of 240Pu/239Pu atomic ratios were 0.258 ± 0.034, 0.219 ± 0.031, and 0.212 ± 0.028 in the sediments of the SCS, eastern IND, and Arabian Sea, respectively. The 240Pu/239Pu atomic ratios in the SCS and IND indicate that Pu from the Pacific Proving Ground (PPG) is transported to the IND via the SCS internal current and transverse ocean currents within Indonesia. In addition, a seawater advection-dispersion equation (S-ADE) model is established based on the actual physical processes of radionuclides in the seawater column and well fitting results were obtained (R2 = 0.49 to 0.99). The 239+240Pu data and the geographic information from the sample site were used to correct the Pu distribution in the seawater. The calculated 239+240Pu mean concentrations in the surface seawater were 2.465 mBq/m3 and 2.205 mBq/m3 for the SCS and the eastern IND seawater, respectively, and the result is consistent with the previous measurements. Then, the 239+240Pu stored in the study area of SCS and eastern IND was estimated to be approximately 1.0-1.4% of the global ocean based on the model. This study provides a useful model for guiding and designing future monitoring of pollution by anthropogenic Pu and other isotopes.
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Affiliation(s)
- Xiaomin Wei
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China; Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Ruihan Zhang
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Jianjun Zhu
- Department of Emergency and Critical Care Medicine, The Second Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Shenzhen Wang
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China; Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Yongjing Guan
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Gang Li
- Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510300, China
| | - Yue Yin
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Zhiyong Liu
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China.
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Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene. Sci Rep 2022; 12:10068. [PMID: 35778413 PMCID: PMC9249778 DOI: 10.1038/s41598-022-14179-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/02/2022] [Indexed: 11/26/2022] Open
Abstract
Plutonium (Pu) has been used as a mid-twentieth century time-marker in various geological archives as a result of atmospheric nuclear tests mainly conducted in 1950s. Advancement of analytical techniques allows us to measure 239Pu and 240Pu more accurately and can thereby reconstruct the Pacific Pu signal that originated from the former Pacific Proving Grounds (PPG) in the Marshall Islands. Here, we propose a novel method that couples annual banded reef building corals and nearshore anoxic marine sediments to provide a marker to precisely determine the start of the nuclear era which is known as a part of the Anthropocene. We demonstrate the efficacy of the methods using sediment obtained from Beppu Bay, Japan, and a coral from Ishigaki Island, Japan. The sedimentary records show a clear Pu increase from 1950, peaking during the 1960s, and then showing a sharp decline during the 1970s. However, a constantly higher isotope ratio between 239Pu and 240Pu suggest an additional contribution other than global fallout via ocean currents. Furthermore, single elevations in 240Pu/239Pu provide supportive evidence of close-in-fallout similar to previous studies. Coral skeletal radiocarbon displays a clear timing with the signatures supporting the reliability of the Beppu Bay sediments as archives and demonstrates the strength of this method to capture potential Anthropocene signatures.
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Wu J, Zheng X, Chen J, Yang G, Zheng J, Aono T. Distributions and impacts of plutonium in the environment originating from the Fukushima Daiichi Nuclear Power Plant accident: An overview of a decade of studies. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 248:106884. [PMID: 35398758 DOI: 10.1016/j.jenvrad.2022.106884] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
This paper reviews the current knowledge on plutonium (Pu) isotopic composition (the atom or activity ratios) and activity concentrations of 238Pu, 239Pu, 240Pu, and 241Pu resulting from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011. In this critical review, we document the characteristic values of Pu atom or activity ratios (fingerprints) and present their spatial distributions around the FDNPP site. Based on multiple Pu fingerprints (238Pu/239+240Pu activity ratio, 240Pu/239Pu atom ratio, and 241Pu/239Pu atom ratio), we clarify that Pu contamination from the FDNPP accident occurred in a restricted terrestrial area, while Pu in the Northwest Pacific Ocean is still predominately sourced from the Pacific Proving Grounds (PPG) and global fallout. Using a simple two end-member mixing model, we calculate average contributions of Pu from the FDNPP accident of 13 ± 20% (n = 180) in soil samples, 55 ± 32% (n = 38) in leaf litter samples, and 67 ± 26% (n = 129) in air dust/black substances. In the marine environment, the PPG source average contributions are 45 ± 15% (n = 76) in seawater and 42 ± 12% (n = 48) in sediments. The spatial distributions of Pu atom or activity ratios based on existing studies suggest that: 1) in the terrestrial region investigated 80 km northwest of the FDNPP site, the Pu contamination is mainly observed in an area within a 50 km distance, and 2) in the terrestrial region investigated 60 km southwest of the FDNPP site, the Pu contamination is mainly observed in an area within a 30 km distance. Studies of Cs-bearing radioactive particles indicate that Pu occurs as Pu oxide, and the fuel fragments containing Pu that were released from the reactors to the surrounding environment are associated with micron-scale Cs-bearing radioactive particles. We note that the fractionation between Pu and other radionuclides occurred after release. These new findings about the Pu fingerprints around the FDNPP site will help researchers to establish a reference background database for future environmental risk assessment and geochemical study there.
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Affiliation(s)
- Junwen Wu
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention & Institute of Marine Sciences, Shantou University, Shantou, 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, China
| | - Xuemin Zheng
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention & Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Jisheng Chen
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention & Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Guosheng Yang
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Jian Zheng
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan.
| | - Tatsuo Aono
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan
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Zhang M, Qiao J, Zhang W, Zhu L, Hou X. Plutonium isotopes in the northwestern South China Sea: Level, distribution, source and deposition. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118846. [PMID: 35032601 DOI: 10.1016/j.envpol.2022.118846] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/05/2022] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
The spatial distribution of plutonium isotopes (239Pu, 240Pu) in the surface sediments collected from the northwestern South China Sea (SCS) in 2018 was investigated. The 239,240Pu concentrations in surface sediments vary from 0.048 to 0.960 mBq/g (with mean of 0.282 ± 0.242 mBq/g) depending on the geographical feature of the sampling location such as the river estuary, continental shelf, slope and deep basin. Higher 240Pu/239Pu atomic ratios (0.24-0.31) in the surface sediment of the SCS compared to the global fallout value of 0.18 were observed, this is attributed to the input of close-in fallout of the Pacific Proving Ground (PPG) transported by the North Equatorial Current and Kuroshio Current to the northern SCS. The contribution of the PPG derived plutonium in the SCS sediment was estimated to be 39%-78% using a simple two-end member mixing model based on the measured 240Pu/239Pu atomic ratios in the sediment. Besides the soluble 239,240Pu level in seawater, load of suspended particulate matter from the river runoff and biological debris, hydrographic and hydrodynamic conditions are key parameters influencing the deposition process of plutonium to the sediment.
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Affiliation(s)
- Mengting Zhang
- State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, PR China; Department of Environmental Engineering, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark; Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, PR China
| | - Jixin Qiao
- Department of Environmental Engineering, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark
| | - Weichao Zhang
- State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, PR China; Northwest Institute of Nuclear Technology, Xi'an, 710024, PR China
| | - Liuchao Zhu
- Department of Environmental Engineering, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark
| | - Xiaolin Hou
- State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, PR China; Department of Environmental Engineering, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark; Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266061, PR China.
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Yamada M, Zheng J. Temporal trend of 240Pu/ 239Pu atom ratios in water columns in the Western North Pacific Ocean and its marginal seas. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 240:106737. [PMID: 34543861 DOI: 10.1016/j.jenvrad.2021.106737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/30/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
The 240Pu/239Pu atom ratios were determined by inductively coupled plasma mass spectrometry for seawater samples from the Okinawa Trough in the western North Pacific Ocean margin to identify their Pu sources and to elucidate the temporal variability in atom ratios in the water columns in the western North Pacific Ocean and its marginal seas. The 239Pu, 240Pu and 239+240Pu water column inventories were 12.2 ± 0.5, 10.5 ± 0.5 and 22.7 ± 0.7 Bq m-2, respectively. The observed 240Pu/239Pu ratios were clearly greater than the mean global fallout ratio of ∼0.18 with a mean value of 0.236 ± 0.014. The observed greater atom ratios confirmed the presence of close-in fallout Pu from nuclear testing at the Pacific Proving Grounds (PPG). The relative percentage of the PPG-derived Pu to global fallout Pu was estimated as 41 ± 10%. The 239+240Pu water column inventory originating from the PPG close-in fallout was also calculated as 9.2 ± 0.4 Bq m-2. The temporal variability in the mean 240Pu/239Pu atom ratios in the water columns in the western North Pacific Ocean and its marginal seas was obtained through comparison of the present study values and the previously reported values, and it had no significant temporal variation with a mean value of 0.237 ± 0.004 during the observation period of 1984-2015. The 239Pu and 240Pu derived from the two different sources of global fallout and the close-in fallout at the PPG were homogenized in the water masses in the studied areas.
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Affiliation(s)
- Masatoshi Yamada
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan; Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan.
| | - Jian Zheng
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan.
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7
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Yamada M, Zheng J. Distributions of 239Pu and 240Pu Concentrations and 240Pu/ 239Pu Atom Ratios and 239+240Pu Inventories in a Water Column in the Eastern Indian Ocean: Transport of Pacific Proving Grounds-Derived Pu via the Indonesian Throughflow. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13849-13859. [PMID: 34569801 DOI: 10.1021/acs.est.1c03575] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The 239+240Pu concentrations and 240Pu/239Pu atom ratios in seawater from the eastern Indian Ocean were determined to identify their Pu sources and to propose the transport pathway of Pacific Proving Grounds (PPG)-derived Pu into the studied area. This is the first study by anyone on these Pu atom ratios in the Indian Ocean. In the West Australia Basin, the 239+240Pu concentration was 2.89 mBq m-3 in the surface water and increased with depth; a subsurface maximum was identified at 200 m depth and then decreased gradually with depth; its water column inventory was 32.8 Bq m-2. The inventory-weighted mean 240Pu/239Pu atom ratios were 0.208 in the South Australia Basin, 0.226 in the Perth Basin, 0.242 in the West Australia Basin, 0.232 in the Bay of Bengal, and 0.225 in the Andaman Sea. The obtained 240Pu/239Pu ratios were clearly greater than the mean global fallout ratio of 0.18. These high atom ratios proved the presence of close-in fallout Pu from PPG nuclear tests. The relative contribution of global and PPG fallouts was evaluated using the two-end-member mixing model. The 239+240Pu inventories originating from the PPG fallout were calculated as 2.9-14.9 Bq m-2, which corresponded to 20-46% of the total 239+240Pu inventory. A significant amount of the PPG-derived Pu has been transported to the eastern Indian Ocean. The proposed transport pathway accounting for the high 240Pu/239Pu ratio is the transportation of PPG-derived Pu by the North Equatorial Current followed by the Mindanao Current, Indonesian Throughflow, and then spreading over the Indian Ocean by its surface circulation system.
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Affiliation(s)
- Masatoshi Yamada
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba 299-5105, Japan
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Jian Zheng
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
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Yamada M, Oikawa S, Shirotani Y, Kusakabe M, Shindo K. Transuranic nuclides Pu, Am and Cm isotopes, and 90Sr in seafloor sediments off the Fukushima Daiichi Nuclear Power Plant during the period from 2012 to 2019. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 227:106459. [PMID: 33221564 DOI: 10.1016/j.jenvrad.2020.106459] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 06/11/2023]
Abstract
The 238Pu, 239+240Pu, 241Am, 242Cm, 243+244Cm and 90Sr concentrations in seafloor surface sediments collected at three sampling stations off the Fukushima Daiichi Nuclear Power Plant (FDNPP) site during the period from 2012 to 2019 were determined to elucidate the impacts of the FDNPP accident onto their concentrations in coastal sediments and to discuss the sources of the measured radionuclides. The 239+240Pu, 241Pu and 241Am concentrations and 240Pu/239Pu atom ratios in a sediment core were also determined to allow comparison of their inventories between this study and previously reported values and to identify the Pu sources. The 238Pu, 239+240Pu, 241Am and 90Sr concentrations showed no remarkable temporal variations; no significant increases in concentrations after the FDNPP accident were observed; these concentrations were comfortably within the previously reported concentration range; and no detectable 242Cm and 243+244Cm amounts were observed in surface sediments. The observed 238Pu/239+240Pu activity ratios were approximately two orders of magnitudes lower than those for the damaged FDNPP reactor core inventories and the observed values in terrestrial samples after the accident. The 239+240Pu, 241Pu and 241Am inventories in the sediment core were 389 ± 5, 503 ± 33 and 214 ± 3 Bq m-2, respectively. The 239+240Pu inventory was about an order of magnitude greater than the expected cumulative deposition density of global fallout from atmospheric nuclear weapons testing due to an enhanced scavenging effect. The 240Pu/239Pu atom ratios in the sediment core ranged from 0.239 to 0.246 with a mean value of 0.242 ± 0.002; these ratios were clearly greater than the mean global fallout ratio of 0.18. The results for 238Pu/239+240Pu activity ratios and 240Pu/239Pu atom ratios reflected a mixture of global fallout and Pacific Proving Grounds (PPG) close-in fallout Pu rather than Fukushima accident-derived Pu. The sediment column inventory for 239+240Pu originating from the PPG close-in fallout was calculated as 166 Bq m-2, which corresponded to 43% of the total inventory. A significant amount of the PPG-derived Pu has been transported by ocean currents and then preferentially scavenged in the coastal waters of Japan.
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Affiliation(s)
- Masatoshi Yamada
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan.
| | - Shinji Oikawa
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan
| | - Yuhei Shirotani
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan
| | - Masashi Kusakabe
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan
| | - Koji Shindo
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba, 299-5105, Japan
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Wu J, Xiao X, Sun J. Distribution and budget of 137Cs in the China Seas. Sci Rep 2020; 10:8795. [PMID: 32472036 PMCID: PMC7260368 DOI: 10.1038/s41598-020-65280-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/30/2020] [Indexed: 11/09/2022] Open
Abstract
Cesium-137 is one of the most abundant anthropogenic radionuclides released by atmospheric nuclear testing and nuclear accidents, and accordingly it may significantly impact the health of humans and marine environmental eco-systems. Documenting the distribution and inventory of 137Cs is thus a crucial task. In this study, we collected a large number of datasets with field observations of 137Cs in the China Seas, in order to provide an in-depth understanding of 137Cs budgets and distributions. The activity and inventory of 137Cs in China Seas' sediments showed large spatial variations, related to the 137Cs source, sedimentation rates and the mineral composition of sediments. The 137Cs concentration in sediments decreased with distance from the shore, generally tracing the distribution of sedimentation rates. High 137Cs inventories in the water column indicated a high solubility and long mean residence times. The mean residence times of 137Cs in the China Seas were determined to be 45.6 ± 3.8 years for the South China Sea (SCS), 36.8 ± 3.1 years for the East China Sea (ECS), and 12.0 ± 1.0 years for the Yellow Sea (YS). A 137Cs mass balance suggests that oceanic input from the north Pacific is the dominant 137Cs source to the China Seas, contributing about 96.9% of this substance. Furthermore, the bulk of 137Cs remains dissolved in the SCS water column, while 137Cs is mostly deposited to the sediments of the ECS and the YS. This new compilation of the activity level and inventory of 137Cs help to establish background levels for future 137Cs studies in the China Seas.
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Affiliation(s)
- Junwen Wu
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China.
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, China.
| | - Xiyu Xiao
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
| | - Jiang Sun
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China
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Yamada M, Zheng J. 240Pu/ 239Pu atom ratios in water columns from the North Pacific Ocean and Bering Sea: Transport of Pacific Proving Grounds-derived Pu by ocean currents. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137362. [PMID: 32088472 DOI: 10.1016/j.scitotenv.2020.137362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/14/2020] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
The 240Pu/239Pu atom ratios in seawater from the northern North Pacific Ocean and Bering Sea were determined to elucidate the temporal variability in 239+240Pu inventory, to identify their Pu sources and to propose the transport pathway of Pacific Proving Grounds (PPG)-derived Pu into the studied area. Water column 239+240Pu inventory in the Bering Sea was lower than that reported for a comparable station in the Geochemical Ocean Sections Study, indicating that the Bering Sea inventory has been decreasing at the average rate of 2.6 Bq m-2 yr-1. The 240Pu/239Pu atom ratios ranged from 0.222 to 0.255 with a mean value of 0.235 in the northern North Pacific Ocean and from 0.215 to 0.237 with a mean value of 0.224 in the Bering Sea. The obtained 240Pu/239Pu ratios were clearly higher than the mean global fallout ratio of 0.18. These high atom ratios proved the presence of close-in fallout Pu from nuclear weapons testing at the PPG. The relative contribution of the global fallout and the PPG fallout were evaluated by using the two-end-member mixing model. The 239+240Pu inventories originating from the PPG fallout were calculated as 17.9-25.4 Bq m-2 in the northern North Pacific Ocean and 11.6-16.6 Bq m-2 in the Bering Sea, which corresponded to 38-54% and 31-45% of the total 239+240Pu inventory in the water column in the northern North Pacific Ocean and Bering Sea, respectively. A significant amount of the PPG-derived Pu has been transported to the northern North Pacific Ocean and Bering Sea. The proposed transport pathway accounting for the high 240Pu/239Pu ratio in the Bering Sea water column is the transportation of PPG-derived Pu by the North Equatorial Current followed by the Kuroshio Current, Kuroshio Extension, North Pacific Current and subsequently the Alaska Current, and then the Alaskan Stream.
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Affiliation(s)
- Masatoshi Yamada
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan; Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku, Isumi, Chiba 299-5105, Japan.
| | - Jian Zheng
- Department of Radioecology and Fukushima Project, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
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Wu J, Sun J, Xiao X. An overview of current knowledge concerning the inventory and sources of plutonium in the China Seas. MARINE POLLUTION BULLETIN 2020; 150:110599. [PMID: 31733905 DOI: 10.1016/j.marpolbul.2019.110599] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 06/10/2023]
Abstract
This study reviews the current understanding of the inventory and sources of plutonium (Pu) in the marine environment adjacent to China. The 239+240Pu inventory in the China Seas was found to have large spatial variations. The quantity in sediments decreases away from the shore, generally tracing the sedimentation rate distribution. High 239+240Pu inventories indicated that Pu in the water column was easily scavenged since Pu has a high particle affinity. Indeed, substantially higher 240Pu/239Pu atom ratios were observed in the sediment and seawater of the China Seas than are found in global fallout. We thus clarified that Pu sources in the China Seas were from both global fallout and the Pacific Proving Grounds (PPG) in the Pacific Marshall Islands. Plutonium from the latter source is transported into the China Seas through the North Equatorial Current (NEC) and Kuroshio. Using a two end-member mixing model, we revealed that the contribution of Pu from the PPG accounts for over 40% of the Pu in the East China Sea (ECS) and South China Sea (SCS), and less than 20% of the Pu in the Yellow Sea (YS). The distributions and isotopic composition of Pu in the China Seas indicate strong scavenging of Pu in the ECS and high Pu accumulation in the SCS. This information on the inventory and isotopic composition of Pu helps to establish a background for the future study of Pu in the China Seas.
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Affiliation(s)
- Junwen Wu
- College of Science, Shantou University, Shantou, 515063, China.
| | - Jiang Sun
- College of Science, Shantou University, Shantou, 515063, China
| | - Xiyu Xiao
- College of Science, Shantou University, Shantou, 515063, China
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Zhang F, Wang J, Liu D, Bi Q, Du J. Distribution of 137Cs in the Bohai Sea, Yellow Sea and East China Sea: Sources, budgets and environmental implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 672:1004-1016. [PMID: 30981889 DOI: 10.1016/j.scitotenv.2019.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/28/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
The transport processes and fate of 137Cs in eastern Chinese seas (ECSs) that consists of the Bohai, Yellow, and East China Seas, have not been well established. In this study, we measured the concentrations of 137Cs in the ECSs water and surface sediments during 2013-2014. Combined with a number of published 137Cs inventory data from drainage basins and sediment accumulation rates in the ECSs, the distribution, sources and budgets of 137Cs in the ECSs were investigated. The 137Cs activity in the water column and surface sediments ranged from 0.03 to 1.92 Bq/m3 and from 0.30 to 5.22 Bq/kg, respectively. No 134Cs signal was observed, suggesting that the Fukushima accident had limited impact on the ECSs during the investigation period. Mass balance of 137Cs suggests that at least 7.4 × 1012 Bq/y of 137Cs imported into the ECSs from the Northwestern Pacific that accounts for 0.7% of the 137Cs transported by the Kuroshio Current, and this value is 5.2 times higher than the sum of atmospheric fallout and total riverine input. The apparent half-lives of 137Cs are estimated to be 15.1 y for the ECS and 7.7 y for the YS. The vertical profiles in the continental shelf edge and the Yangtze River Estuary reveal that the upwelling of the Kuroshio Subsurface Water is the main mechanism of 137Cs import into the ECSs. The high level of 137Cs in oceanic water masses and the low level of 137Cs in riverine and coastal waters make 137Cs a good indicator for tracing water mass movement and interaction. In addition, good correlation between 137Cs activity and mean grain size (φ) indicates that 137Cs can serve as an effective tracer to track dispersal pathways of fine sediments in river-dominated marginal seas.
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Affiliation(s)
- Fule Zhang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Jinlong Wang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China.
| | - Dantong Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Qianqian Bi
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
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Men W, Zheng J, Wang H, Ni Y, Kumamoto Y, Yamada M, Uchida S. Pu isotopes in the seawater off Fukushima Daiichi Nuclear Power Plant site within two months after the severe nuclear accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:303-310. [PMID: 30557804 DOI: 10.1016/j.envpol.2018.12.007] [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: 07/25/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
The marine environment is complex, and it is desirable to have measurements for seawater samples collected at the early stage after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident to determine the impact of Fukushima-derived radionuclides on this environment. Here Pu isotopes in seawater collected 33-163 km from the FDNPP site at the very early stage after the accident were determined (May 2011, within two months after the accident). The distribution and temporal variation of 239Pu and 240Pu were studied. The results indicated that both 239+240Pu activity concentrations (from 0.81 ± 0.16 to 11.18 ± 1.28 mBq/m3) and 240Pu/239Pu atom ratios (from 0.216 ± 0.032 to 0.308 ± 0.036) in these seawater samples were within the corresponding background ranges before the accident, and this suggested that Fukushima-derived Pu isotopes, if any, were in too limited amount to be distinguished from the background level in the seawater. The analysis of Pu isotopic composition indicated that the major sources of Pu in the seawater after the accident were still global fallout and the Pacific Proving Ground close-in fallout. The contribution analysis showed that the contributions of the Pacific Proving Ground close-in fallout in the water column of the study area ranged from 26% to 77% with the average being 48%.
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Affiliation(s)
- Wu Men
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan; Laboratory of Marine Isotopic Technology and Environmental Risk Assessment, Third Institute of Oceanography, State Oceanic Administration, 184 Daxue Road, Xiamen, 361005, China
| | - Jian Zheng
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.
| | - Hai Wang
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan; School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China
| | - Youyi Ni
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Yuichiro Kumamoto
- Research and Development Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Masatoshi Yamada
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Shigeo Uchida
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
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Marine radioactivity of Cs-134 and Cs-137 in the Malaysian Economic Exclusive Zone after the Fukushima accident. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-6306-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wu J. Sources and scavenging of plutonium in the East China Sea. MARINE POLLUTION BULLETIN 2018; 135:808-818. [PMID: 30301101 DOI: 10.1016/j.marpolbul.2018.08.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
The 240Pu/239Pu atom ratio and 239+240Pu activity of seawater in the East China Sea (ECS) was measured in order to examine the Pu sources and elaborate Pu scavenging process. High 240Pu/239Pu atom ratios (0.187-0.243, average = 0.221 ± 0.017) in the surface water and water column were observed during 2011, implying of non-global fallout Pu sources. The distribution of 240Pu/239Pu atom ratio in the ECS was in agreement with the introduction pathway of the Kuroshio, showing a decreasing trend away from the outer shelf. An even higher 240Pu/239Pu atom ratios (0.243-0.263, average = 0.253 ± 0.007) were observed in the Kuroshio, indicating the non-global fallout Pu signal from the Pacific Proving Grounds (PPG). Using a two end-member mixing model, the Pu source from the PPG contribution was calculated to be 36 ± 9% in the ECS seawater. The 239+240Pu activities of surface seawater were in the range of 2.00-2.95 mBq m-3 in the ECS. The spatial distribution of 239+240Pu activity in the surface seawater showed an increasing trend from the outer shelf to the nearshore. Moreover, 239+240Pu inventory of water column at the station DH23 in the ECS was calculated to be ~0.29 Bq m-2, which was 1-3 orders of magnitude lower than the estimates of sediment cores in the ECS shelf (9-407 Bq m-2). Such differences were determined by the high degree Pu scavenging efficiency in the ECS and high Pu input carried by terrestrial sediments from the Yangtze River. Finally, both 240Pu/239Pu atom ratios and 239+240Pu activities were identical before and after the Fukushima nuclear accident (FNA), suggesting that the impact of the FNA on the ECS was negligible.
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Affiliation(s)
- Junwen Wu
- Institute of Marine Biology, College of Science, Shantou University, Shantou 515063, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiang'an District, Xiamen 361102, China.
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Hao Y, Xu Y, Pan S, Song X, Zhang K, Guo H, Gu Z. Sources of plutonium isotopes and 137Cs in coastal seawaters of Liaodong Bay and Bohai Strait, China and its environmental implications. MARINE POLLUTION BULLETIN 2018; 130:240-248. [PMID: 29866553 DOI: 10.1016/j.marpolbul.2018.03.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/21/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
In order to investigate the sources of plutonium in seawaters of Liaodong Bay and Bohai Strait, China, surface seawater samples were collected and analyzed for 239+240Pu and 137Cs by radiochemical separation combined with ICP-MS and γ-spectrometry, respectively. A large variation of 239+240Pu activities was observed, ranging from 1.993 to 29.677 mBq/m3 in the Liaodong Bay and from 0.932 to 10.183 mBq/m3 in the Bohai Strait. 137Cs activities showed little variation between the investigated locations, which was attributed to the different behavior characteristics of 239+240Pu and 137Cs in seawaters. The 240Pu/239Pu atom ratios showed a significant variation between the Liaodong Bay (0.185) and Bohai Strait (0.225), indicating that Pu derived from the Pacific Proving Grounds might have been transported to the Bohai Strait but not yet to the Liaodong Bay, which could further provide valuable reference for evaluating the seawater exchange cycle between the Bohai Sea and Yellow Sea.
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Affiliation(s)
- Yongpei Hao
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
| | - Yihong Xu
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
| | - Shaoming Pan
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
| | - Xiaowei Song
- State Key Laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China
| | - Kexin Zhang
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China
| | - Haiting Guo
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
| | - Zhi Gu
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
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Zhao L, Liu D, Wang J, Du J, Hou X, Jiang Y. Spatial and vertical distribution of radiocesium in seawater of the East China Sea. MARINE POLLUTION BULLETIN 2018; 128:361-368. [PMID: 29571384 DOI: 10.1016/j.marpolbul.2018.01.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
The 137Cs activity in surface water of the East China Sea (ECS) was 0.66-1.36 Bq m-3 during May of 2011. The low activities were observed in the Changjiang Estuary and Zhejiang-Fujian coast and high activities were observed in the south offshore and Kuroshio Current pathway, suggesting that the influence from the current system in the ECS. The 134Cs were undetectable (<0.03 Bq m-3) and the contribution of the Fukushima accident to ECS is estimated to be below 3%; hence it is negligible during the investigation period. Using the vertical profiles of 137Cs in the ECS, the mass balance is obtained, which suggests that the oceanic input dominates the 137Cs source in the ECS. 137Cs is potentially useful to trace water mass movement in the ECS. Our study provides comprehensive baseline of 137Cs in the ECS for evaluation of the possible influence of the nuclear power plants in the future.
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Affiliation(s)
- Lijun Zhao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Dantong Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jinlong Wang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Xiaolin Hou
- Xi'an AMS Center and KLLQG, Institute of Earth Environment, Chinese Academy of Science, Xi'an 710075, China
| | - Yifei Jiang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
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Wu J. Impacts of Fukushima Daiichi Nuclear Power Plant accident on the Western North Pacific and the China Seas: Evaluation based on field observation of 137Cs. MARINE POLLUTION BULLETIN 2018; 127:45-53. [PMID: 29475684 DOI: 10.1016/j.marpolbul.2017.11.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/20/2017] [Accepted: 11/23/2017] [Indexed: 06/08/2023]
Abstract
After the Fukushima nuclear accident (FNA), 137Cs activities of seawater in the Western North Pacific (WNP) and China Seas were determined in order to examine whether 137Cs derived from FNA across the Kuroshio was still existed and if there were any indications of FNA's impact. High 137Cs activities at 200-500m were observed in the south of Kuroshio during 2015, indicating 137Cs from FNA could cross the Kuroshio. Surface 137Cs activities were on average 1.43±0.42Bqm-3 for WNP, 1.11±0.14Bqm-3 for South China Sea (SCS) and 1.10±0.29Bqm-3 for East China Sea (ECS) during 2011-2015. The activities and inventories of 137Cs were almost identical before and after the FNA, indicating the impacts of FNA on the WNP and China Seas were minor. The effective environmental half-lives of 137Cs in surface seawater were firstly estimated to be 14.4±1.7yrs for ECS and 16.9±2.1yrs for SCS.
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Affiliation(s)
- Junwen Wu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiang'an District, Xiamen 361102, China; Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV-SRTE Laboratoire de Recherche sur les Transferts des radionucléides au sein écosystèmes Aquatiques (LRTA) Centre IFREMER de Méditerranée, CS 20330, zone portuaire de Brégaillon, 83507 La Seyne-sur-Mer Cedex, France.
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Wu J, Dai M, Xu Y, Zheng J. Sources and accumulation of plutonium in a large Western Pacific marginal sea: The South China Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:200-211. [PMID: 28803197 DOI: 10.1016/j.scitotenv.2017.07.226] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/25/2017] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
In order to examine the sources of plutonium (Pu) and elaborate its scavenging and accumulation processes, 240Pu/239Pu atom ratios and 239+240Pu activities in the water column of the South China Sea (SCS) were determined and compared with our previously reported data for the sediments. Consistently high 240Pu/239Pu atom ratios that ranged from 0.184-0.250 (average=0.228±0.015), indicative of non-global fallout Pu sources were observed both in the surface water and at depth during 2012-2014. The spatial distribution of the 240Pu/239Pu atom ratio in the SCS showed a decreasing trend away from the Luzon Strait, which was very consistent with the introduction pathway of the Kuroshio Current. The Kuroshio had an even heavier Pu isotopic ratio ranging from 0.250-0.263 (average=0.255±0.006), traceable to the non-global fallout Pu signature from the Pacific Proving Grounds (PPG). Using a simple two end-member mixing model, we further revealed that this PPG source contributed 41±17% of the Pu in the SCS water column. The 239+240Pu activities in the SCS surface seawater varied from 1.59 to 2.94mBqm-3, with an average of 2.34±0.38mBqm-3. Such an activity level was ~40% higher than that in the Kuroshio. The distribution of 239+240Pu in the surface seawater further showed a general trend of increase from the Kuroshio to the SCS basin, suggesting significant accumulation of Pu within the SCS. The 239+240Pu inventory of the water column in the SCS basin at the SEATS station with a total depth of ~3840m was estimated to be ~29Bqm-2, which was substantially higher than the sediment core estimates made for the SCS basin (3.75Bqm-2) but much lower than the sediment core estimates made for the shelf of the northern SCS (365.6Bqm-2). Such differences were determined by the lower scavenging efficiency of Pu in the SCS basin compared to the northern SCS shelf.
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Affiliation(s)
- Junwen Wu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiang'an District, Xiamen 361102, China
| | - Minhan Dai
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiang'an District, Xiamen 361102, China.
| | - Yi Xu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiang'an District, Xiamen 361102, China
| | - Jian Zheng
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba 263-8555, Japan
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Zhang K, Pan S, Liu Z, Li G, Xu Y, Hao Y. Vertical distributions and source identification of the radionuclides 239Pu and 240Pu in the sediments of the Liao River estuary, China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 181:78-84. [PMID: 29107833 DOI: 10.1016/j.jenvrad.2017.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 10/22/2017] [Accepted: 10/27/2017] [Indexed: 06/07/2023]
Abstract
Activity concentration of plutonium (Pu) and its isotopic compositions are extensively used for measuring transport processes of Pu and identifying its source. We investigated the spatial distribution characteristics of 239+240Pu activity concentrations and 240Pu/239Pu atom ratio in several sediment cores collected from the Liao River coastal zone. Additionally, we calculated the 239+240Pu inventories and based on the 240Pu/239Pu atom ratio to trace Pu source. The activity concentrations of 239+240Pu in surface sediments of the Liao River estuary ranged between 0.103 ± 0.008 and 0.978 ± 0.035 mBq/g, with an average of 0.294 ± 0.024 mBq/g. The 240Pu/239Pu atom ratios, ranging from 0.173 ± 0.047 to 0.215 ± 0.061 (mean: 0.188 ± 0.049 (1σ)), were consistent with global fallout value, which indicates the global atmospheric fallout is the main source of Pu in sediment cores from the both sides of Liao River estuary. As for the tidal flat core LT-2, the mean 240Pu/239Pu atom ratio, slightly higher than that of the global fallout value, was 0.217 ± 0.050. Such pattern of Pu isotopic compositions indicated that Pu on the tidal flat in the Liao River estuary is sourced from a combination of global fallout and close-in fallout from the PPG by ocean currents transporting. And by using a two end-member mixing model, the results indicate the relative contribution of the PPG close-in fallout to core LT-2 is round 27% and 73% can be attributed to global fallout and river input. Therefore, these results clearly indicate that the direct global fallout is the main source of Pu in the Liao River estuary.
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Affiliation(s)
- Kexin Zhang
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China; College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China
| | - Shaoming Pan
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
| | - Zhiyong Liu
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, China
| | - Guosheng Li
- Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China.
| | - Yihong Xu
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
| | - Yongpei Hao
- The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
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Pittauer D, Tims SG, Froehlich MB, Fifield LK, Wallner A, McNeil SD, Fischer HW. Continuous transport of Pacific-derived anthropogenic radionuclides towards the Indian Ocean. Sci Rep 2017; 7:44679. [PMID: 28304374 PMCID: PMC5356341 DOI: 10.1038/srep44679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/13/2017] [Indexed: 11/09/2022] Open
Abstract
Unusually high concentrations of americium and plutonium have been observed in a sediment core collected from the eastern Lombok Basin between Sumba and Sumbawa Islands in the Indonesian Archipelago. Gamma spectrometry and accelerator mass spectrometry data together with radiometric dating of the core provide a high-resolution record of ongoing deposition of anthropogenic radionuclides. A plutonium signature characteristic of the Pacific Proving Grounds (PPG) dominates in the first two decades after the start of the high yield atmospheric tests in 1950's. Approximately 40-70% of plutonium at this site in the post 1970 period originates from the PPG. This sediment record of transuranic isotopes deposition over the last 55 years provides evidence for the continuous long-distance transport of particle-reactive radionuclides from the Pacific Ocean towards the Indian Ocean.
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Affiliation(s)
- Daniela Pittauer
- University of Bremen, MARUM - Center for Marine Environmental Sciences, Bremen, 28359, Germany.,University of Bremen, Institute of Environmental Physics, Bremen, 28359, Germany
| | - Stephen G Tims
- Australian National University, Department of Nuclear Physics, Canberra, ACT 2601, Australia
| | - Michaela B Froehlich
- Australian National University, Department of Nuclear Physics, Canberra, ACT 2601, Australia
| | - L Keith Fifield
- Australian National University, Department of Nuclear Physics, Canberra, ACT 2601, Australia
| | - Anton Wallner
- Australian National University, Department of Nuclear Physics, Canberra, ACT 2601, Australia
| | - Steven D McNeil
- Australian National University, Department of Nuclear Physics, Canberra, ACT 2601, Australia
| | - Helmut W Fischer
- University of Bremen, Institute of Environmental Physics, Bremen, 28359, Germany
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Meusburger K, Mabit L, Ketterer M, Park JH, Sandor T, Porto P, Alewell C. A multi-radionuclide approach to evaluate the suitability of (239+240)Pu as soil erosion tracer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:1489-1499. [PMID: 27338845 DOI: 10.1016/j.scitotenv.2016.06.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/06/2016] [Accepted: 06/06/2016] [Indexed: 06/06/2023]
Abstract
Fallout radionuclides have been used successfully worldwide as tracers for soil erosion, but relatively few studies exploit the full potential of plutonium (Pu) isotopes. Hence, this study aims to explore the suitability of the plutonium isotopes (239)Pu and (240)Pu as a method to assess soil erosion magnitude by comparison to more established fallout radionuclides such as (137)Cs and (210)Pbex. As test area an erosion affected headwater catchment of the Lake Soyang (South Korea) was selected. All three fallout radionuclides confirmed high erosion rates for agricultural sites (>25tha(-1)yr(-1)). Pu isotopes further allowed determining the origin of the fallout. Both (240)Pu/(239)Pu atomic ratios and (239+240)Pu/(137)Cs activity ratios were close to the global fallout ratio. However, the depth profile of the (239+240)Pu/(137)Cs activity ratios in undisturbed sites showed lower ratios in the top soil increments, which might be due to higher migration rates of (239+240)Pu. The activity ratios further indicated preferential transport of (137)Cs from eroded sites (higher ratio compared to the global fallout) to the depositional sites (smaller ratio). As such the (239+240)Pu/(137)Cs activity ratio offered a new approach to parameterize a particle size correction factor that can be applied when both (137)Cs and (239+240)Pu have the same fallout source. Implementing this particle size correction factor in the conversion of (137)Cs inventories resulted in comparable estimates of soil loss for (137)Cs and (239+240)Pu. The comparison among the different fallout radionuclides highlights the suitability of (239+240)Pu through less preferential transport compared to (137)Cs and the possibility to gain information regarding the origin of the fallout. In conclusion, (239+240)Pu is a promising soil erosion tracer, however, since the behaviour i.e. vertical migration in the soil and lateral transport during water erosion was shown to differ from that of (137)Cs, there is a clear need for a wider agro-environmental testing.
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Affiliation(s)
- Katrin Meusburger
- Environmental Geosciences, University of Basel, Bernoullistrasse 30, CH-4056 Basel, Switzerland.
| | - Lionel Mabit
- Soil and Water Management and Crop Nutrition Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories, Seibersdorf, Austria.
| | - Michael Ketterer
- Chemistry Department, Metropolitan State University of Denver, CO, USA.
| | - Ji-Hyung Park
- Department of Environmental Science & Engineering, Ewha Womans University, Seoul 120-750, Republic of Korea.
| | - Tarjan Sandor
- Radioanalytical Reference Laboratory, Central Agricultural Office Food and Feed Safety Directorate, Hungary
| | - Paolo Porto
- Dipartimento di AGRARIA, Università degli Studi "Mediterranea" di Reggio Calabria, Italy.
| | - Christine Alewell
- Environmental Geosciences, University of Basel, Bernoullistrasse 30, CH-4056 Basel, Switzerland.
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23
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Sartandel SJ, Jha SK, Tripathi RM. Latitudinal variation and residence time of (137)Cs in Indian coastal environment. MARINE POLLUTION BULLETIN 2015; 100:489-494. [PMID: 26383130 DOI: 10.1016/j.marpolbul.2015.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/18/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
Anthropogenic (137)Cs activity concentration, in surface sea water along the western and eastern coast of India has been estimated using the in-situ pre-concentration approach. Activity levels of (137)Cs ranges from 0.09-1.30Bqm(-3) with an overall mean of 0.69±0.29Bqm(-3). Latitudinal variation and higher depletion in activity concentration of (137)Cs at few locations were observed. Temporal change of (137)Cs in sea water along Indian coast unveils a lower effective half-life of 13.8±0.7y in comparison to Asia Pacific regional sea water. The results prevailed that the spatial distribution confers no fresh input of (137)Cs in Indian coastal region.
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Affiliation(s)
- S J Sartandel
- Health Physics Division, Bhabha Atomic Research Center, Mumbai 400 085, India
| | - S K Jha
- Health Physics Division, Bhabha Atomic Research Center, Mumbai 400 085, India.
| | - R M Tripathi
- Health Physics Division, Bhabha Atomic Research Center, Mumbai 400 085, India
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24
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Using 239+240Pu atmospheric deposition and a simplified mass-balance model to re-estimate the soil erosion rate: a case study of Liaodong Bay in China. J Radioanal Nucl Chem 2015. [DOI: 10.1007/s10967-015-4208-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Oikawa S, Watabe T, Takata H. Distributions of Pu isotopes in seawater and bottom sediments in the coast of the Japanese archipelago before and soon after the Fukushima Dai-ichi Nuclear Power Station accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 142:113-123. [PMID: 25659922 DOI: 10.1016/j.jenvrad.2015.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/16/2014] [Accepted: 01/06/2015] [Indexed: 06/04/2023]
Abstract
A radioactivity measurement survey was carried out from 24 April 2008 to 3 June 2011 to determine the levels of plutonium isotopes and (240)Pu/(239)Pu atom ratios in the marine environments off the sites of commercial nuclear power stations around the Japanese islands; the sampling period extended to two months after the Fukushima Dai-ichi Nuclear Power Station accident. In our previous study (Oikawa et al., 2015), data on Pu isotopes and (241)Am in sediments have already been reported. In this study, we report those on Pu isotopes in seawater as well as sediments, and the characteristics of sediments in addition (e.g., ignition loss and biogenic opals). Concentrations of (239+240)Pu in seawater and bottom sediments remained nearly constant at all sampling locations during the survey period. In addition, no regional differences were observed in the (239+240)Pu concentrations in surface waters. Higher (239+240)Pu concentrations were found in bottom waters at deeper sampling locations, but the (240)Pu/(239)Pu atom ratios were nearly constant regardless of the water depth. Higher (239+240)Pu concentrations were also found in bottom sediments at deeper sampling locations, but vice versa for (240)Pu/(239)Pu atom ratios as reported in the previous report. The sediments samples from deeper locations showed the higher percentage of ignition loss as well as the higher content of biogenic opal. There was likely to be some driving force participating in the transfer of Pu isotopes associated with biogenic substances to the deeper seabed. The present survey showed that the accident at the Fukushima Dai-ichi Nuclear Power Station did not contribute much to the inventory of Pu isotopes in the adjacent sea area.
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Affiliation(s)
- Shinji Oikawa
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumu-gun, Chiba 299-5105, Japan
| | - Teruhisa Watabe
- Head Office, Marine Ecology Research Institute, Towa-Edogawabashi Bldg. 7F., 347 Yamabuki-cho, Shinjuku, Tokyo 162-0801, Japan
| | - Hyoe Takata
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumu-gun, Chiba 299-5105, Japan.
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26
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Bu W, Zheng J, Aono T, Wu J, Tagami K, Uchida S, Guo Q, Yamada M. Pu Distribution in Seawater in the Near Coastal Area off Fukushima after the Fukushima Daiichi Nuclear Power Plant Accident. ACTA ACUST UNITED AC 2015. [DOI: 10.14494/jnrs.15.1_1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- W.T. Bu
- Research Center for Radiation Protection, National Institute of Radiological Sciences
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University
| | - J. Zheng
- Research Center for Radiation Protection, National Institute of Radiological Sciences
| | - T. Aono
- Research Center for Radiation Protection, National Institute of Radiological Sciences
| | - J.W. Wu
- Research Center for Radiation Protection, National Institute of Radiological Sciences
- State Key Laboratory of Marine Environment Science, Xiamen University
| | - K. Tagami
- Research Center for Radiation Protection, National Institute of Radiological Sciences
| | - S. Uchida
- Research Center for Radiation Protection, National Institute of Radiological Sciences
| | - Q.J. Guo
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University
| | - M. Yamada
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University
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27
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Wu J, Zheng J, Dai M, Huh CA, Chen W, Tagami K, Uchida S. Isotopic composition and distribution of plutonium in northern South China Sea sediments revealed continuous release and transport of Pu from the Marshall Islands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:3136-3144. [PMID: 24564849 DOI: 10.1021/es405363q] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The (239+240)Pu activities and (240)Pu/(239)Pu atom ratios in sediments of the northern South China Sea and its adjacent Pearl River Estuary were determined to examine the spatial and temporal variations of Pu inputs. We clarified that Pu in the study area is sourced from a combination of global fallout and close-in fallout from the Pacific Proving Grounds in the Marshall Islands where above-ground nuclear weapons testing was carried out during the period of 1952-1958. The latter source dominated the Pu input in the 1950s, as evidenced by elevated (240)Pu/(239)Pu atom ratios (>0.30) in a dated sediment core. Even after the 1950s, the Pacific Proving Grounds was still a dominant Pu source due to continuous transport of remobilized Pu from the Marshall Islands, about 4500 km away, along the North Equatorial Current followed by the transport of the Kuroshio current and its extension into the South China Sea through the Luzon Strait. Using a simple two end-member mixing model, we have quantified the contributions of Pu from the Pacific Proving Grounds to the northern South China Sea shelf and the Pearl River Estuary are 68% ± 1% and 30% ± 5%, respectively. This study also confirmed that there were no clear signals of Pu from the Fukushima Daiichi Nuclear Power Plant accident impacting the South China Sea.
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Affiliation(s)
- Junwen Wu
- State Key Laboratory of Marine Environmental Science, Xiamen University , Xiamen, Fujian 361005, P. R. China
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28
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Watabe T, Oikawa S, Isoyama N, Suzuki C, Misonoo J, Morizono S. Spatiotemporal distribution of 137Cs in the sea surrounding Japanese Islands in the decades before the disaster at the Fukushima Daiichi Nuclear Power Plant in 2011. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 463-464:913-921. [PMID: 23872184 DOI: 10.1016/j.scitotenv.2013.06.031] [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: 02/04/2013] [Revised: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 06/02/2023]
Abstract
The historic spatiotemporal distribution of 137Cs in the seawaters and sea-floor sediments adjacent to nuclear power plants in Japan are summarized, using data obtained over a period of time more than 20 years prior to the disaster at the Fukushima Daiichi Nuclear Power Plant in 2011. Relatively uniform distributions of 137Cs were observed both in the surface seawaters (1 m in depth) and in deeper seawaters (10 to 30 m above the seabed and ranging from tens to hundreds of meters in depth) independent of the geographical position, although lower concentrations were observed in significantly deeper bottom seawaters. Conversely, there were wide variations in 137Cs levels between sediments, such that higher 137Cs concentrations were observed in the deeper sampling locations. A mathematical model describing the successive transfer of 137Cs from surface waters through deeper waters to sediments suggested that the transfer rate of 137Cs from deep water to the sediments, and the loss rate from bottom sediments, were both greater than the transfer rate from surface water to deeper water. It was found that the calculated regression lines for 137Cs depletion rates over time for surface waters, deeper waters, and sediments were approximately parallel when plotted on a semi-logarithmic coordinate system, regardless of the sampling location. A radionuclide depletion half-life was calculated to be 4 months to 16 years with the geometric mean of 2.22 y for the sediments in the Fukushima region, suggesting that nuclear contamination will be remediated over time through sediment redistribution processes such as remobilization, bioturbation, and migration due to sea currents.
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Affiliation(s)
- Teruhisa Watabe
- Research and Survey Group, Head Office, Marine Ecology Research Institute, Towa Edogawabashi Bldg. 7F., Yamabuki-cho 347, Shinjuku-ku, Tokyo 162-0801, Japan.
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29
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Zheng J, Tagami K, Uchida S. Release of plutonium isotopes into the environment from the Fukushima Daiichi Nuclear Power Plant accident: what is known and what needs to be known. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:9584-9595. [PMID: 23899337 DOI: 10.1021/es402212v] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has caused serious contamination in the environment. The release of Pu isotopes renewed considerable public concern because they present a large risk for internal radiation exposure. In this Critical Review, we summarize and analyze published studies related to the release of Pu from the FDNPP accident based on environmental sample analyses and the ORIGEN model simulations. Our analysis emphasizes the environmental distribution of released Pu isotopes, information on Pu isotopic composition for source identification of Pu releases in the FDNPP-damaged reactors or spent fuel pools, and estimation of the amounts of Pu isotopes released from the FDNPP accident. Our analysis indicates that a trace amount of Pu isotopes (∼2 × 10(-5)% of core inventory) was released into the environment from the damaged reactors but not from the spent fuel pools located in the reactor buildings. Regarding the possible Pu contamination in the marine environment, limited studies suggest that no extra Pu input from the FDNPP accident could be detected in the western North Pacific 30 km off the Fukushima coast. Finally, we identified knowledge gaps remained on the release of Pu into the environment and recommended issues for future studies.
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Affiliation(s)
- Jian Zheng
- Research Center of Radiation Protection, National Institute of Radiological Sciences , Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
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30
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Khan MF, Wesley SG. Radionuclides in resident and migratory fishes of a wedge bank region: Estimation of dose to human beings, South India. MARINE POLLUTION BULLETIN 2012; 64:2224-2232. [PMID: 22763281 DOI: 10.1016/j.marpolbul.2012.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/07/2012] [Accepted: 06/09/2012] [Indexed: 06/01/2023]
Abstract
Baseline activity concentration of (137)Cs, (210)Po and (210)Pb was determined for 25 resident and 22 migratory fish species collected in a so-called wedge bank region in the extreme south of India. A nuclear power station is now under construction at Kudankulam near the target region and the data provide background information on the radionuclide activity concentration in the region. Three-way ANOVA revealed no significant variation in the concentrations of (137)Cs, (210)Po and (210)Pb between species based on feeding habit, habitat and migratory pattern except the effect of feeding habit on (210)Po concentration (p<0.05). The annual dose due to radionuclide ingestion through the fishes was calculated based on the survey results of fish consumption rates for the local population. The dose due to (137)Cs was negligibly small while those due to (210)Po and (210)Pb varied from 1.2 to 36.9 and 0.2 to 2.9μSv yr(-1), respectively.
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Affiliation(s)
- M Feroz Khan
- Department of Advanced Zoology and Biotechnology, Sadakathullah Appa College (Autonomous), Rahmath Nagar, Palayamkottai 627 011, Tirunelveli District, Tamil Nadu, India.
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31
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Alonso-Hernández CM, Martin-Perez J, Gasco C, Díaz-Asencio M, Bolanos-Álvarez Y, Gómez-Batista M. Vertical distribution and inventories of (239+240)Pu and mercury in Sagua la Grande estuary, Cuba. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2012; 112:23-28. [PMID: 22484472 DOI: 10.1016/j.jenvrad.2012.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 03/01/2012] [Accepted: 03/02/2012] [Indexed: 05/31/2023]
Abstract
The vertical activity distribution and inventories of (239+240)Pu profile and Hg were determined in Sagua la Grande estuary, Cuba. The shape of the (239+240)Pu profile in the core column resembled very closely the history of atmospheric nuclear weapons' testing, and the maximum deposition in 1963 was recorded in the sediment core history. The (239+240)Pu activity concentrations in the surface layer sediments varied from 0.163 to 0.611 mBq g(-1). The inventory of (239+240)Pu was 42 ± 5.6 Bq m(-2), a value close to that expected from direct global fallout. Using the (239+240)Pu as a chronomarker the mass sedimentation rate in the area for the last 60 years was calculated, reaching values of 0.173 g cm(-2) y(-1). The mercury profile reflects the history of anthropogenic pollution in the estuary and perfectly describes the operation of the mercury-cell chlor-alkali plant, for production of NaOH, which began operations in 1980. The inventory of Hg was 2.42 ± 0.19 μg cm(-2). These results contribute to the scarce regional database for pollutants and anthropogenic radionuclides in the Caribbean marine environment, particularly in relation to (239+240)Pu.
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Affiliation(s)
- C M Alonso-Hernández
- Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, CP 59350 Cienfuegos, Cuba.
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32
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Impacts of the Fukushima nuclear accident on the China Seas: Evaluation based on anthropogenic radionuclide 137Cs. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5426-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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33
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Yamada M, Zheng J. ²³⁹Pu and ²⁴⁰Pu inventories and ²⁴⁰Pu/²³⁹Pu atom ratios in the equatorial Pacific Ocean water column. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 430:20-27. [PMID: 22613463 DOI: 10.1016/j.scitotenv.2012.04.065] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/24/2012] [Accepted: 04/25/2012] [Indexed: 06/01/2023]
Abstract
The (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios were determined by alpha spectrometry and inductively coupled plasma mass spectrometry for seawater samples from two stations, one at the equator and the other in the equatorial South Pacific. To better understand the fate of Pu isotopes, this study dealt with the contribution of the close-in fallout Pu from the Pacific Proving Grounds (PPG) in water columns of the Pacific Ocean. The (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m at the equator station were 10.4, 8.9 and 19.3 Bq m(-2), respectively. Further, no noticeable difference was observed in (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m between the two stations. The total (239+240)Pu inventories were significantly higher than the expected cumulative deposition density of global fallout. Water column (239+240)Pu inventories measured in this study were lower than those reported for comparable stations in the Geochemical Ocean Sections Study, indicating that these inventories have been decreasing at average rates of 0.89 ± 0.07 and 0.16 ± 0.07 Bq m(-2)yr(-1) at the equator and equatorial South Pacific stations, respectively, from 1973 to 1990. The obtained (240)Pu/(239)Pu atom ratios were higher than the mean global fallout ratio of 0.18. These high atom ratios proved the existence of close-in tropospheric fallout Pu from the PPG in the Marshall Islands. The (239+240)Pu inventories originating from the close-in fallout in the entire water column were estimated to be 11.1 Bq m(-2) at the equator station and 7.1 Bq m(-2) at the equatorial South Pacific Ocean station, and the relative percentages of close-in fallout Pu were 40% at the former and 34% at the latter. A significant amount of close-in fallout Pu originating from the PPG has been transported to deep layers below the 1000 m depth in the equatorial Pacific Ocean.
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Affiliation(s)
- Masatoshi Yamada
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
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34
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Ketterer ME, Zheng J, Yamada M. Applications of Transuranics as Tracers and Chronometers in the Environment. ADVANCES IN ISOTOPE GEOCHEMISTRY 2012. [DOI: 10.1007/978-3-642-10637-8_20] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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35
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Yamada M, Zheng J. Determination of 240Pu/239Pu atom ratio in seawaters from the East China Sea. RADIATION PROTECTION DOSIMETRY 2011; 146:311-313. [PMID: 21502295 DOI: 10.1093/rpd/ncr178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The (240)Pu/(239)Pu atom ratios in seawater samples on the East China Sea continental shelf were measured. These ratios for surface and bottom waters had no significant difference. They were significantly higher than the average global fallout ratio of 0.18. It was proposed that the oceanic currents are accounted for delivery of close-in Pu from the Pacific Proving Grounds (PPG) to the studied areas. The contribution of the PPG close-in fallout was calculated to be 40 % on average. The (240)Pu/(239)Pu atom ratios should provide useful background data before the expected expansion of nuclear power capacity in East and South Asian countries and for distinguishing future sources of Pu.
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Affiliation(s)
- Masatoshi Yamada
- Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
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36
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Yii MW, Wan Mahmood ZU. Radioactivity of plutonium isotopes, 137Cs and their ratio in sediment, seawater and biota from the east coast of Peninsular Malaysia. J Radioanal Nucl Chem 2011. [DOI: 10.1007/s10967-011-1149-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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37
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Oikawa S, Watabe T, Inatomi N, Isoyama N, Misonoo J, Suzuki C, Nakahara M, Nakamura R, Morizono S, Fujii S, Hara T, Kido K. Plutonium isotopes concentration in seawater and bottom sediment off the Pacific coast of Aomori sea area during 1991-2005. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2011; 102:302-310. [PMID: 21227553 DOI: 10.1016/j.jenvrad.2010.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 12/20/2010] [Accepted: 12/24/2010] [Indexed: 05/30/2023]
Abstract
A radioactivity survey was launched in 1991 to determine the background levels of ²³⁹+²⁴⁰Pu in the marine environment off a commercial spent nuclear fuel reprocessing plant before full operation of the facility. Particular attention was focused on the ²⁴⁰Pu/²³⁹Pu atom ratio in seawater and bottom sediment to identify the origins of Pu isotopes. The concentration of ²³⁹+²⁴⁰Pu was almost uniform in surface water, decreasing slowly over time. Conversely, the ²³⁹+²⁴⁰Pu concentration varied markedly in the bottom water and was dependent upon the sampling point, with higher concentrations of ²³⁹+²⁴⁰Pu observed in the bottom water sample at sampling points having greater depth. The ²⁴⁰Pu/²³⁹Pu atom ratio in the seawater and sediment samples was higher than that of global fallout Pu, and comparable with the data in the other sea area around Japan which has likely been affected by close-in fallout Pu originating from the Pacific Proving Grounds. The ²⁴⁰Pu/²³⁹Pu atom ratio in bottom sediment samples decreased with sea depth. The land-originated Pu is not considered as the reason of the increasing ²³⁹+²⁴⁰Pu concentration and also decreasing the ²⁴⁰Pu/²³⁹Pu atom ratio with sea depth, and further study is required to clarify it.
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Affiliation(s)
- Shinji Oikawa
- Marine Ecology Research Institute, Head Office, Research and Survey Group, Towa-Edogawabashi Bldg. 7F., 347 Yamabuki-cho, Shinjuku-ku, Tokyo 162-0801, Japan.
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38
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Liu Z, Zheng J, Yamada M, Pan S, Kawahata H. Plutonium characteristics in sediments of Hiroshima Bay in the Seto Inland Sea in Japan. J Radioanal Nucl Chem 2011. [DOI: 10.1007/s10967-011-1025-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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39
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Yamada M, Zheng J. Temporal variation of 240Pu/239Pu atom ratio and 239+240Pu inventory in water columns of the Japan Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:5951-5957. [PMID: 20869751 DOI: 10.1016/j.scitotenv.2010.08.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 05/29/2023]
Abstract
The (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios were determined by alpha spectrometry and double-focusing SF-ICP-MS for seawater samples obtained in 1984 and 1993 from the Yamato and Tsushima Basins of the Japan Sea in the western North Pacific margin. The total (239+240)Pu inventories in the whole water columns were approximately doubled during the period from 1984 to 1993 in the two basins. The increasing rates were estimated to be 5.1 Bq m(-2)yr(-1) in the Yamato Basin and 4.2 Bq m(-2)yr(-1) in the Tsushima Basin and they corresponded to ~0.02% of the annual (239+240)Pu inflow rate into the Japan Sea through the Tsushima Strait. The mean (240)Pu/(239)Pu atom ratios were ~0.240 and significantly higher than the mean global fallout ratio of 0.18. Furthermore, there were no temporal or spatial variations of (240)Pu/(239)Pu atom ratios during this period in the Japan Sea. The total (239+240)Pu inventories originating from the close-in fallout increased from 17.6 Bq m(-2) to 34.6 Bq m(-2) in the Yamato Basin and from 20.1 Bq m(-2) to 34.6 Bq m(-2) in the Tsushima Basin; however, the relative percentage of ~40% from the close-in fallout was unchanged during this period. A likely mechanism for the increasing Pu inventory would be the continuous inflow of the Tsushima Current from the western North Pacific, and the removal of Pu from surface waters by scavenging onto the settling particles, followed by regeneration of Pu from the settling particles during the downward transport.
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Affiliation(s)
- Masatoshi Yamada
- Environmental Radiation Effects Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
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40
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Biomonitoring of 137Cs fall-out in Kudankulam coastal waters, Gulf of Mannar, India. J Radioanal Nucl Chem 2010. [DOI: 10.1007/s10967-010-0616-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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41
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Ahmad Z, Mei-Wo Y, Abu Bakar AS, Shahar H. Spatial distributions of 137Cs and 239+240Pu in surface seawater within the Exclusive Economic Zone of East Coast Peninsular Malaysia. Appl Radiat Isot 2010; 68:1839-45. [DOI: 10.1016/j.apradiso.2010.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 01/04/2010] [Accepted: 04/01/2010] [Indexed: 12/01/2022]
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42
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Dong W, Zheng J, Guo Q, Yamada M, Pan S. Characterization of plutonium in deep-sea sediments of the Sulu and South China Seas. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:622-629. [PMID: 20403651 DOI: 10.1016/j.jenvrad.2010.03.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 03/15/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
Anthropogenic Pu isotopes are important geochemical tracers for sediment studies. Their distributions and sources in the water columns as well as the sediments of the North Pacific have been intensively studied; however, information about Pu in the Southeast Asian seas is limited. To study the isotopic composition of Pu, and thus to identify its sources, we collected sediment core samples in the South China Sea and the Sulu Sea during the KH-96-5 Cruise of the R/V Hakuho Maru. We analysed the activities of (239+240)Pu and the atom ratios of (240)Pu/(239)Pu using isotope dilution sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS). The (240)Pu/(239)Pu atom ratios in the sediments of both areas (inventory weighted mean: 0.251 for the South China Sea and 0.280 for the Sulu Sea) were higher than the global fallout value (0.178+/-0.019), suggesting the existence of Pu from the Pacific Proving Grounds in the North Pacific. Low inventories of (239+240)Pu in sediments were observed in the South China Sea (3.75 Bq/m(2)) and the Sulu Sea (1.38 Bq/m(2)). Most of the Pu input is still present in the water column. Scavenging and benthic mixing processes were considered to be the main processes controlling the distribution of Pu in the deep-sea sediments of both study areas.
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Affiliation(s)
- Wei Dong
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, 100871, China; Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 491 Anagawa, Inage, Chiba 263-8555, Japan
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Lindahl P, Lee SH, Worsfold P, Keith-Roach M. Plutonium isotopes as tracers for ocean processes: a review. MARINE ENVIRONMENTAL RESEARCH 2010; 69:73-84. [PMID: 19773079 DOI: 10.1016/j.marenvres.2009.08.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 05/28/2023]
Abstract
Since the first nuclear weapons tests in the 1940s, pulsed inputs of plutonium isotopes have served as excellent tracers for understanding sources, pathways, dynamics and the fate of pollutants and particles in the marine environment. Due to the well-defined spatial and temporal inputs of Pu, the long half-lives of (240)Pu and (239)Pu and its unique chemical properties, Pu is a potential tracer for various physical and biogeochemical ocean processes, including circulation, sedimentation and biological productivity, and hence a means of assessing the impacts of global climate change. Due to the source dependency of the Pu isotopic signature, plutonium isotopes are beginning to be exploited as tools for the evaluation and improvement of regional and global ocean models that will enhance understanding of past and future changes in the oceans. This paper addresses the major sources of Pu and the physical and biogeochemical behaviour in the marine environment. Finally, the use of Pu isotopes as tracers for various oceanic processes (e.g. water mass transport, particle export, and sedimentation) is considered.
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Affiliation(s)
- Patric Lindahl
- Marine Environment Research Department, Korea Ocean Research and Development Institute, Ansan, P.O. Box 29, Seoul 425-600, Republic of Korea.
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Hirose K, Aoyama M, Povinec PP. 239,240Pu/137Cs ratios in the water column of the North Pacific: a proxy of biogeochemical processes. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2009; 100:258-262. [PMID: 19176268 DOI: 10.1016/j.jenvrad.2008.12.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 12/11/2008] [Accepted: 12/20/2008] [Indexed: 05/27/2023]
Abstract
Anthropogenic radionuclides in seawater have been used as transient tracers of processes in the marine environment. Especially, plutonium in seawater is considered to be a valuable tracer of biogeochemical processes due to its particle-reactive properties. However, its behavior in the ocean is also affected by physical processes such as advection, mixing and diffusion. Here we introduce Pu/(137)Cs ratio as a proxy of biogeochemical processes and discuss its trends in the water column of the North Pacific Ocean. We observed that the (239,240)Pu/(137)Cs ratio in seawater exponentially increased with increasing depth (depth range: 100-1000 m). This finding suggests that the profiles of the (239,240)Pu/(137)Cs ratios in shallower waters directly reflect biogeochemical processes in the water column. A half-regeneration depth deduced from the curve fitting the observed data, showed latitudinal and longitudinal distributions, also related to biogeochemical processes in the water column.
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Affiliation(s)
- Katsumi Hirose
- Geochemical Research Department, Meteorological Research Institute, Nagamine 1-1, Tsukuba, Ibaraki 305-0052, Japan.
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Liao H, Zheng J, Wu F, Yamada M, Tan M, Chen J. Determination of plutonium isotopes in freshwater lake sediments by sector-field ICP-MS after separation using ion-exchange chromatography. Appl Radiat Isot 2008; 66:1138-45. [DOI: 10.1016/j.apradiso.2008.01.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 10/09/2007] [Accepted: 01/07/2008] [Indexed: 10/22/2022]
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Everett SE, Tims SG, Hancock GJ, Bartley R, Fifield LK. Comparison of Pu and (137)Cs as tracers of soil and sediment transport in a terrestrial environment. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:383-393. [PMID: 18063237 DOI: 10.1016/j.jenvrad.2007.10.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/24/2007] [Accepted: 10/24/2007] [Indexed: 05/25/2023]
Abstract
Following atmospheric nuclear weapons testing in the 1950s and 1960s significant quantities of (137)Cs and (239+240)Pu were deposited worldwide. In recent decades, (137)Cs has been commonly used as a tracer of soil erosion and sedimentation, particularly in the Northern Hemisphere where atomic deposition was three times as great as in the Southern Hemisphere. The relatively short 30-year half-life of this isotope means that its sensitivity as a tracer is rapidly decreasing. In contrast, with half-lives of 24,110 and 6561 years, the sensitivity of the two plutonium isotopes remains essentially the same as when it was deposited. Here we use the technique of Accelerator Mass Spectrometry to demonstrate the potential of anthropogenic Pu as an alternative to (137)Cs as a tracer of soil transport in Australia. We measure an average (137)Cs/(239+240)Pu activity ratio of 27.3+/-1.5 and an average (240)Pu/(239)Pu atom ratio of 0.149+/-0.003, both slightly lower than the global average.
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Affiliation(s)
- S E Everett
- Department of Nuclear Physics, Research School of Physical Sciences and Engineering, The Australian National University, Building 57, Canberra, 0200 ACT, Australia.
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Yamada M, Zheng J. Determination of 240Pu/239Pu atom ratio in coastal surface seawaters from the western North Pacific Ocean and Japan Sea. Appl Radiat Isot 2008; 66:103-7. [PMID: 17870557 DOI: 10.1016/j.apradiso.2007.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 08/04/2007] [Indexed: 11/20/2022]
Abstract
Surface seawater samples were collected from a site in the vicinity of the nuclear fuel reprocessing facility at Rokkasho, Japan and sites along the Japan Sea coast. (239+240)Pu activities and (240)Pu/(239)Pu atom ratios were determined by alpha-spectrometry and isotope-dilution sector-field ICP-MS. The (240)Pu/(239)Pu atom ratio with the mean value of 0.227 +/- 0.006 was significantly higher than the mean global fallout ratio of 0.18. The contribution of the Pacific Proving Grounds close-in fallout was estimated to be 33% of the (239+240)Pu.
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Affiliation(s)
- Masatoshi Yamada
- Nakaminato Laboratory for Marine Radioecology, Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202, Japan.
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Determination of plutonium isotopes in marine particles collected by the large volume in situ filtration and concentration system. J Radioanal Nucl Chem 2007. [DOI: 10.1007/s10967-007-7049-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hirose K, Aoyama M, Fukasawa M, Kim CS, Komura K, Povinec PP, Sanchez-Cabeza JA. Plutonium and 137Cs in surface water of the South Pacific Ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 381:243-55. [PMID: 17459459 DOI: 10.1016/j.scitotenv.2007.03.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 03/15/2007] [Accepted: 03/19/2007] [Indexed: 05/15/2023]
Abstract
The present plutonium and 137Cs concentrations in South Pacific Ocean surface waters were determined. The water samples were collected in the South Pacific mid-latitude region (32.5 degrees S) during the BEAGLE expedition conducted in 2003-04 by JAMSTEC. 239,240Pu concentrations in surface seawater of the South Pacific were in the range of 0.5 to 4.1 mBq m(-3), whereas 137Cs concentrations ranged from 0.07 to 1.7 Bq m(-3). The observed 239,240Pu and 137Cs concentrations in the South Pacific were almost of the same level as those in the North Pacific subtropical gyre. The surface 239,240Pu in the South Pacific subtropical gyre showed larger spatial variations than 137Cs, as it may be affected by physical and biogeochemical processes. The 239,240Pu/137Cs activity ratios, which reflect biogeochemical processes in seawater, were generally smaller than that observed in global fallout, except for the most eastern station. The 239,240Pu/137Cs ratios in the South Pacific tend to be higher than that in the North Pacific. The relationships between anthropogenic radionuclides and oceanographic parameters such as salinity and nutrients were examined. The 137Cs concentrations in the western South Pacific (the Tasman Sea) and the eastern South Pacific were negatively correlated with the phosphate concentration, whereas there is no correlation between the 137Cs and nutrients concentrations in the South Pacific subtropical gyre. The mutual relationships between anthropogenic radionuclides and oceanographic parameters are important for better understanding of transport processes of anthropogenic radionuclides and their fate in the South Pacific.
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Affiliation(s)
- K Hirose
- Meteorological Research Institute, Nagamine 1-1, Tsukuba, Ibaraki 305-0052, Japan.
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Krachler M. Environmental applications of single collector high resolution ICP-MS. ACTA ACUST UNITED AC 2007; 9:790-804. [PMID: 17671659 DOI: 10.1039/b703823m] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The number of environmental applications of single collector high resolution ICP-MS (HR-ICP-MS) has increased rapidly in recent years. There are many factors that contribute to make HR-ICP-MS a very powerful tool in environmental analysis. They include the extremely low detection limits achievable, tremendously high sensitivity, the ability to separate ICP-MS signals of the analyte from spectral interferences, enabling the reliable determination of many trace elements, and the reasonable precision of isotope ratio measurements. These assets are improved even further using high efficiency sample introduction systems. Therefore, external factors such as the stability of laboratory blanks are frequently the limiting factor in HR-ICP-MS analysis rather than the detection power. This review aims to highlight the most recent applications of HR-ICP-MS in this sector, focusing on matrices and applications where the superior capabilities of the instrumental technique are most useful and often ultimately required.
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Affiliation(s)
- Michael Krachler
- Institute of Environmental Geochemistry, University of Heidelberg, Im Neuenheimer Feld 236, 69120, Heidelberg, Germany.
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