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Zhao X, Hou X, Huang Z, Tang L. Source, preservation and re-suspension of 239,240Pu in a well dated peat core collected from northwest China. CHEMOSPHERE 2024; 359:142267. [PMID: 38719122 DOI: 10.1016/j.chemosphere.2024.142267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/21/2024] [Accepted: 05/04/2024] [Indexed: 05/12/2024]
Abstract
Owning to the high radiotoxicity in high concentrations, as well as the irreplaceability in quantifying soil erosion rates, demarcating the Anthropocene, and dating of sediment, anthropogenic 239,240Pu have drawn high attention. However, the source in specific areas, preservation characteristics in different environment media, and re-distribution process after the cessation of atmospheric nuclear weapons tests, have not been fully understood, which obscures the exact start year, temporal variation, and deposition flux of 239,240Pu in sedimentary records, and hinders the wide application of 239,240Pu in environment study. A sediment core from the Yiwu peat bog with dominance of atmospheric deposition in the source material, simple sedimentary environment, and high dust deposition flux, was collected to examine the 239,240Pu, and explore the source, preservation, and re-distribution process. The double peaks of 239,240Pu in 1952 CE and 1963 CE, as well as 240Pu/239Pu ratios of 0.163-0.190 with an average of 0.177 ± 0.010 confirmed that the 239,240Pu source originated predominantly from global fallout. The minimal vertical migration of plutonium in the Yiwu peat core was attributed to the near-neutral pH condition. The high inventory of 128 ± 7 Bq m-2, as well as the atypical negative correlation between 239,240Pu concentrations and organic matter content (r = - 0.79, P < 0.01), was attributed to the contribution of 239,240Pu re-suspended with dust from the neighboring Gobi Desert, particularly in the cold and dry years. The total re-suspended 239,240Pu was estimated to be 77 Bq m-2, exceeding the direct fallout level of 51 Bq m-2 during 1945-2016 CE. In this study, the specified deposition pattern of 239,240Pu after the cessation of atmospheric nuclear weapons was established, providing an important standard for multiple environmental studies, and the re-suspended amount of 239,240Pu in a typical arid area was quantified for the first time.
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Affiliation(s)
- Xue Zhao
- State Key Laboratory of Loess Science, 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; Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, PR China; Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266061, PR China
| | - Xiaolin Hou
- State Key Laboratory of Loess Science, 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; Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266061, PR China.
| | - Zhao Huang
- State Key Laboratory of Loess Science, 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; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Lu Tang
- Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, PR China
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2
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Bessonov AA, Shilov VP. Behavior of Plutonium(V) in the Environment. RADIOCHEMISTRY 2022. [DOI: 10.1134/s1066362222060029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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3
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Sanchez-Cabeza JA, Rico-Esenaro SD, Corcho-Alvarado JA, Röllin S, Carricart-Ganivet JP, Montagna P, Ruiz-Fernández AC, Cearreta A. Plutonium in coral archives: A good primary marker for an Anthropocene type section. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 771:145077. [PMID: 33736122 DOI: 10.1016/j.scitotenv.2021.145077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
While we officially live in the Holocene epoch, global warming and many other impacts of global change have led to the proposal and wide adoption of the Anthropocene to define the present geological epoch. The Anthropocene Working Group (AWG) established that it should be treated as a formal stratigraphic unit, demonstrated by a reference level commonly known as "golden spike", still under discussion. Here we show that the onset of bomb-derived plutonium recorded in two banded massive corals from the Caribbean Sea is consistent (1955-1956 CE), so sites far from nuclear testing grounds are potentially suitable to host a type section of the Anthropocene. Coastal coral demonstration sites are feasible, could foster economic development, and may serve as focal points for scientific dissemination and environmental education.
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Affiliation(s)
- Joan-Albert Sanchez-Cabeza
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Mexico.
| | - Serguei Damián Rico-Esenaro
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Stefan Röllin
- Nuclear Chemistry Division, Spiez Laboratory, Federal Office for Civil Protection, CH-3700 Spiez, Switzerland
| | - Juan P Carricart-Ganivet
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | | | - Ana Carolina Ruiz-Fernández
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Mexico
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4
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López-Lora M, Levy I, Chamizo E. Simple and fast method for the analysis of 236U, 237Np, 239Pu and 240Pu from seawater samples by Accelerator Mass Spectrometry. Talanta 2019; 200:22-30. [DOI: 10.1016/j.talanta.2019.03.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 11/28/2022]
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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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6
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Mihalik J, Madruga MJ, Casimiro MH, Ferreira LM, Prudêncio MI. Redistribution of Cs 137 introduced into montmorillonite in association with organic matter coming from biomass composting. CHEMOSPHERE 2018; 207:147-153. [PMID: 29793026 DOI: 10.1016/j.chemosphere.2018.05.078] [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: 12/12/2017] [Revised: 04/16/2018] [Accepted: 05/13/2018] [Indexed: 06/08/2023]
Abstract
The adsorption and later bioavailability of 137Cs from the system humic acid (HA)/humic acid like compounds (HALC) and montmorillonite was investigated. The setup of the experiments should approach as much as possible natural conditions when 137Cs is introduced into soil with HALC from decomposed biomass. The significant differences were found in the trials containing various HA/HALC and also pure montmorillonite. The 137Cs was more available when it reached soil in association with HALC originated from compost than when it was adsorbed on stable humic acids. Moreover, the long term interaction of 137Cs with HALC led to decrease of 137Cs adsorbed on montmorillonite and increase of its bioavailable fraction. UV-Vis spectrometry and infrared spectroscopy showed the clear difference between HA, fresh HALC and old HALC which could partially explain the different results.
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Affiliation(s)
- J Mihalik
- Centro de Ciências e Tecnologias Nucleares (C(2)TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal.
| | - M J Madruga
- Centro de Ciências e Tecnologias Nucleares (C(2)TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal; Laboratório de Proteção e Segurança Radiológica, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal
| | - M H Casimiro
- Centro de Ciências e Tecnologias Nucleares (C(2)TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal
| | - L M Ferreira
- Centro de Ciências e Tecnologias Nucleares (C(2)TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal
| | - M I Prudêncio
- Centro de Ciências e Tecnologias Nucleares (C(2)TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal
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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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8
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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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9
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Cao L, Bu W, Zheng J, Pan S, Wang Z, Uchida S. Plutonium determination in seawater by inductively coupled plasma mass spectrometry: A review. Talanta 2016; 151:30-41. [DOI: 10.1016/j.talanta.2016.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 10/22/2022]
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10
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Pearson AJ, Gaw S, Hermanspahn N, Glover CN. Activity concentrations of (137)Caesium and (210)Polonium in seafood from fishing regions of New Zealand and the dose assessment for seafood consumers. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 3:542-550. [PMID: 26272653 DOI: 10.1016/j.jenvrad.2015.07.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 06/26/2015] [Accepted: 07/05/2015] [Indexed: 06/04/2023]
Abstract
A study was undertaken to determine activity concentrations for (134)Caesium, (137)Caesium and (210)Polonium in New Zealand seafood, and establish if activity concentrations varied with respect to species/ecological niche and coastal region. Thirty seafood samples were obtained from six fishing regions of New Zealand along with a further six samples of two commercially important species (hoki and arrow squid) with well-defined fisheries. (134)Caesium was not detected in any sample. (137)Caesium was detected in 47% of samples, predominantly in pelagic fish species, with most activities at a trace level. Detections of (137)Caesium were evenly distributed across all regions. Activity concentrations were consistent with those expected from the oceanic inventory representing residual fallout from global nuclear testing. (210)Polonium was detected above the minimum detectable concentration in 33 (92%) of the analysed samples. Molluscs displayed significantly elevated activity concentrations relative to all other species groups. No significant regional variation in activity concentrations were determined. Two dose assessment models for high seafood consumers were undertaken. Dose contribution from (137)Caesium was minimal and far below the dose exemption limit of 1 mSv/year. Exposure to (210)Polonium was significant in high seafood consumers at 0.44-0.77 mSv/year (5th-95th percentile). (137)Caesium is concluded to be a valuable sentinel radionuclide for monitoring anthropogenic releases, such as global fallout and reactor releases, in the marine environment. (210)Polonium is of importance as a natural radionuclide sentinel due to its high contribution to dietary committed dose in seafood consumers.
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Affiliation(s)
- Andrew J Pearson
- Ministry for Primary Industries, PO Box 2526, Wellington 6140, New Zealand; University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
| | - Sally Gaw
- University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
| | - Nikolaus Hermanspahn
- Institute of Environmental Science & Research Ltd, PO Box 29-181, Christchurch 8540, New Zealand.
| | - Chris N Glover
- University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
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11
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Hancock GJ, Leslie C, Everett SE, Tims SG, Brunskill GJ, Haese R. Plutonium as a chronomarker in Australian and New Zealand sediments: a comparison with (137)Cs. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2011; 102:919-929. [PMID: 19857913 DOI: 10.1016/j.jenvrad.2009.09.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 09/09/2009] [Accepted: 09/16/2009] [Indexed: 05/28/2023]
Abstract
The construction of high resolution chronologies of sediment profiles corresponding to the last 50-100 years usually entails the measurement of fallout radionuclides (210)Pb and (137)Cs. The anthropogenic radionuclide, (137)Cs, originating from atmospheric nuclear weapons testing can provide an important "first appearance" horizon of known age (1954-1955), providing much-needed validation for the sometimes uncertain interpretations associated with (210)Pb geochronology. However, while (137)Cs usually provides a strong signal in sediment in the northern hemisphere, total fallout of (137)Cs in the southern hemisphere was only 25% that of the north and the low activities of (137)Cs seen in Australian and New Zealand sediments can make its horizon of first appearance somewhat arguable. Low (137)Cs fallout also limited the size of the 1963-1964 fallout peak, a peak that is usually seen in northern hemisphere sediment profiles but is often difficult to discern south of the equator. This paper shows examples of the use of nuclear weapons fallout Pu as a chronomarker in sediment cores from Australia (3 sites) and New Zealand (1 site). The Pu profiles of five cores are examined and compared with the corresponding (137)Cs profiles and (210)Pb geochronologies. We find that Pu has significant advantages over (137)Cs, including greater measurement sensitivity using alpha spectrometry and mass spectrometric techniques compared to (137)Cs measurements by gamma spectrometry. Moreover, Pu provides additional chronomarkers associated with changes in the Pu isotopic composition of fallout during the 1950s and 1960s. In particular, the (238)Pu/(239+240)Pu activity ratio shows distinct shifts in the early 1950s and the mid to late 1960s, providing important known-age horizons in southern hemisphere sediments. For estuarine and near-shore sediments Pu sometimes has another significant advantage over (137)Cs due to its enrichment in bottom sediment relative to (137)Cs resulting from the more efficient scavenging of dissolved Pu in seawater by sediment particles.
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Affiliation(s)
- G J Hancock
- CSIRO Land and Water, Black Mountain Laboratories, Canberra, Australia.
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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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13
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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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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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Inomata Y, Aoyama M, Hirose K. Analysis of 50-y record of surface137Cs concentrations in the global ocean using the HAM-global database. ACTA ACUST UNITED AC 2009; 11:116-25. [DOI: 10.1039/b811421h] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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