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Qiao J, Andersson K, Nielsen S. Half-century trends of radioactivity in fish from Danish areas of the North Sea, Kattegat, and Baltic Sea. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123681. [PMID: 38428789 DOI: 10.1016/j.envpol.2024.123681] [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: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
This work reports comprehensive time-series datasets over the past 50 years for natural (210Po) and anthropogenic (134Cs and 137Cs) radionuclides in three fish species (cod, herring and plaice) from Danish marine areas covering the North Sea, Kattegat, and Baltic Sea. Impact from the global fallout of atmospheric nuclear weapons testing, radioactive discharges from the European nuclear reprocessing plants and release from Chernobyl accident are clearly detected in the fish samples. While 210Po concentrations in each fish species demonstrated comparable levels across the three regions without notable temporal trends, significantly higher median 210Po concentration was observed in the lower trophic level fish, namely herring and plaice, compared to cod. In contrast, 137Cs concentrations in all three species steadily decrease over time after the Chernobyl-attributed peaks in late 1980s in the entire study area, whereas 137Cs always demonstrated higher concentrations in cod than herring and plaice. Our calculated concentration factors (CFs) for 137Cs in this work indicate that the mean CFs for 137Cs over the past 50 years are significantly different across the three species, following the order of cod < herring < plaice. Based on the time-series data, ecological half-lives (Teco) of 137Cs in fish from Danish marine areas were estimated to evaluate the long-term impact of anthropogenic radioactive contamination in different regions. Our results indicate no significant difference in Teco across different fish species, whereas the weighted mean Teco for fish in the Baltic Sea (29.3 ± 3.9 y) is significantly longer than those of the North Sea (9.8 ± 0.9 y) and Kattegat (11.7 ± 1.2 y), reflecting the strong 'memory effect' of the Baltic Sea due to its slow water renewal. However, the dose assessment demonstrates that the contribution of the natural radionuclide 210Po to ingestion dose from fish consumption is 1-2 order of magnitude higher compared to that of 137Cs.
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Affiliation(s)
- Jixin Qiao
- Department of Environmental and Resource Engineering, Technical University of Denmark (DTU), DTU Risø Campus, DK-4000, Roskilde, Denmark.
| | - Kasper Andersson
- Department of Environmental and Resource Engineering, Technical University of Denmark (DTU), DTU Risø Campus, DK-4000, Roskilde, Denmark
| | - Sven Nielsen
- Department of Environmental and Resource Engineering, Technical University of Denmark (DTU), DTU Risø Campus, DK-4000, Roskilde, Denmark
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Qiao J, Heldal HE, Steier P. Understanding source terms of anthropogenic uranium in the Arctic Ocean - First 236U and 233U dataset in Barents Sea sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157503. [PMID: 35872206 DOI: 10.1016/j.scitotenv.2022.157503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
This work reports the first dataset of 236U and 233U in sediment cores taken from the Barents Sea, with the aim to better understand the source terms of anthropogenic uranium in the Arctic region. Concentrations of 236U and 233U along with 137Cs, and 233U/236U atomic ratio were measured in six sediment profiles. The cumulative areal inventories of 236U and 233U obtained in this work are (3.50-12.7) × 1011 atom/m2 and (4.92-21.2) × 109 atom/m2, with averages values of (8.08 ± 2.93) × 1011 atom/m2 and (1.08 ± 0.56) × 1010 atom/m2, respectively. The total quantities of 236U and 233U deposited in the Barents Sea bottom sediments were estimated to be 507 ± 184 g and 7 ± 3 g, respectively, which are negligible compared to the total direct deposition of 236U (6000 g) and 233U (40-90 g) from global fallout in the Barents Sea. The integrated atomic ratios of 233U/236U ranging in (0.98-1.57) × 10-2 reflect the predominant global fallout signal of 236U in the Barents Sea sediments and the highest reactor-236U contribution accounts for 30 ± 14 % among the six sediment cores. The reactor-236U input in the Barents Sea sediments is most likely transported from the European reprocessing plants rather than related to any local radioactive contamination. These results provide better understanding on the source term of anthropogenic 236U in the Barents Sea, prompt the oceanic tracer application of 236U for studying the dynamics of the Atlantic-Arctic Ocean and associated climate changes. The 236U-233U benchmarked age-depth profiles seem to match reasonably well with the reported input function history of radioactive contamination in the Barents Sea, indicating the high potential of anthropogenic 236U-233U pair as a useful tool for sediment dating.
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Affiliation(s)
- Jixin Qiao
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark.
| | - Hilde Elise Heldal
- Department of Contaminants and Biohazards, Institute of Marine Research, P.O.Box 1870 Nordnes, NO-5817 Bergen, Norway
| | - Peter Steier
- VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
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Shao Y, Zhang J, Luo M, Xu D, Ma L. A review of anthropogenic radionuclide 236U: Environmental application and analytical advances. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106944. [PMID: 35696882 DOI: 10.1016/j.jenvrad.2022.106944] [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: 05/30/2022] [Accepted: 06/05/2022] [Indexed: 06/15/2023]
Abstract
236U is an anthropogenic radionuclide that is produced from nuclear reactions of 235U(n, γ) and 238U(n, 3n). It has gained extensive attention in the field of environment, geology, nuclear emergency, and nuclear forensics. Due to the unique physical and chemical character and the distinct fingerprint character from different sources, 236U has been successfully applied in the environmental tracer, nuclear material source appointment, and environmental assessment. Until now, few reviews were published about the database, application, and the latest analytical technology development of 236U. In this review, the 236U concentration and 236U/238U isotope ratio were summarized, and the data were classified into four categories, including soil and seawater samples affected by global fallout and nuclear incidents. Furthermore, the development of environmental application and pretreatment methods were also summarized. The advanced pretreatment technology using alkali fusion and flow injection was especially discussed to introduce the development of a rapid analytical method. Finally, the research challenge and direction of 236U were proposed for further research, such as the tracer application combining 236U with other radionuclides in the terrestrial environment and the precise analysis of minor isotopes in ultra-trace uranium samples. We hope this review will help scholars to have a deep research on the analysis and application of 236U.
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Affiliation(s)
- Yang Shao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Jilong Zhang
- State Nuclear Security Technology Center, Beijing, 102401, China
| | - Min Luo
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Diandou Xu
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Lingling Ma
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
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Lin M, Qiao J, Hou X, Steier P, Golser R, Schmidt M, Dellwig O, Hansson M, Bäck Ö, Vartti VP, Stedmon C, She J, Murawski J, Aldahan A, Schmied SAK. Anthropogenic 236U and 233U in the Baltic Sea: Distributions, source terms, and budgets. WATER RESEARCH 2022; 210:117987. [PMID: 34954368 DOI: 10.1016/j.watres.2021.117987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
The Baltic Sea receives substantial amounts of hazardous substances and nutrients, which accumulate for decades and persistently impair the Baltic ecosystems. With long half-lives and high solubility, anthropogenic uranium isotopes (236U and 233U) are ideal tracers to depict the ocean dynamics in the Baltic Sea and the associated impacts on the fates of contaminants. However, their applications in the Baltic Sea are hampered by the inadequate source-term information. This study reports the first three-dimensional distributions of 236U and 233U in the Baltic Sea (2018-2019) and the first long-term hindcast simulation for reprocessing-derived 236U dispersion in the North-Baltic Sea (1971-2018). Using 233U/236U fingerprints, we distinguish 236U from the nuclear weapon testing and civil nuclear industries, which have comparable contributions (142 ± 13 and 174 ± 40 g) to the 236U inventory in modern Baltic seawater. Budget calculations for 236U inputs since the 1950s indicate that, the major 236U sources in the Baltic Sea are the atmospheric fallouts (∼1.35 kg) and discharges from nuclear reprocessing plants (> 211 g), and there is a continuous sink of 236U to the anoxic sediments (589 ± 43 g). Our findings also indicate that the limited water renewal endows the Baltic Sea a strong "memory effect" retaining aged 236U signals, and the previously unknown 236U in the Baltic Sea is likely attributed to the retention of the mid-1990s' discharges from the nuclear reprocessing plants. Our preliminary results demonstrate the power of 236U-129I dual-tracer in investigating water-mass mixing and estimating water age in the Baltic Sea, and this work provides fundamental knowledge for future 236U tracer studies in the Baltic Sea.
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Affiliation(s)
- Mu Lin
- Department of Environmental Engineering, DTU Risø Campus, Technical University of Denmark, Roskilde DK-4000, Denmark
| | - Jixin Qiao
- Department of Environmental Engineering, DTU Risø Campus, Technical University of Denmark, Roskilde DK-4000, Denmark.
| | - Xiaolin Hou
- Department of Environmental Engineering, DTU Risø Campus, Technical University of Denmark, Roskilde DK-4000, Denmark
| | - Peter Steier
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, Vienna A-1090, Austria
| | - Robin Golser
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, Vienna A-1090, Austria
| | - Martin Schmidt
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock 18119, Germany
| | - Olaf Dellwig
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock 18119, Germany
| | - Martin Hansson
- Swedish Meteorological and Hydrological Institute (SMHI), Göteborg SE-426 71, Sweden
| | - Örjan Bäck
- Swedish Meteorological and Hydrological Institute (SMHI), Göteborg SE-426 71, Sweden
| | - Vesa-Pekka Vartti
- Radiation and Nuclear Safety Authority (STUK), Helsinki 00880, Finland
| | - Colin Stedmon
- National Institute of Aquatic Resources, DTU Lyngby Campus, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Jun She
- Department of Research and Development, Danish Meteorological Institute, København DK-2100, Denmark
| | - Jens Murawski
- Department of Research and Development, Danish Meteorological Institute, København DK-2100, Denmark
| | - Ala Aldahan
- Department of Geosciences, United Arab Emirates University, Al Ain 17551, United Arab Emirates
| | - Stefanie A K Schmied
- Federal Maritime and Hydrographic Agency of Germany (BSH), Hamburg 22589, Germany
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Qiao J, Ransby D, Steier P. Deciphering anthropogenic uranium sources in the equatorial northwest Pacific margin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150482. [PMID: 34844331 DOI: 10.1016/j.scitotenv.2021.150482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
This work reports the first high-resolution deposition records of anthropogenic uranium (236U and 233U) in a sediment core taken at the continental slope of the Philippine Sea off Mindanao Island in the equatorial northwest Pacific Ocean. Two notable peaks were observed in both profiles of 236U and 233U concentrations, with a narrower peak in 1951-1957 corresponding to close-in Pacific Proving Grounds (PPG) signal, and a broader peak in 1960s-1980s corresponding to the global fallout from nuclear weapons testing. 236U and 233U areal cumulative inventories in the studied sediment core are (2.79 ± 0.20) ∙ 1012 atom ∙ m-2 and (3.12 ± 0.41) ∙ 1010 atom ∙ m-2, respectively, about 20-30% of reported 233U and 236U inventories from the direct global fallout deposition. The overall 233U/236U atomic ratios obtained in this work vary within (0.3-3.5) ∙ 10-2, with an integrated 233U/236U atomic ratio of (1.12 ± 0.17) ∙ 10-2. The contribution from global fallout and close-in PPG fallout to 236U in the sediment core is estimated to be about 69% and 31%, respectively. We believe the main driving process for anthropogenic uranium deposition in the Philippine sediment is continuous scavenging of dissolved 236U from the surface seawater by sinking particles.
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Affiliation(s)
- Jixin Qiao
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark.
| | - Daniela Ransby
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Peter Steier
- VERA Laboratory, Faculty of Physics, Isotope Research, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
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Lin M, Qiao J, Hou X, Dellwig O, Steier P, Hain K, Golser R, Zhu L. 70-Year Anthropogenic Uranium Imprints of Nuclear Activities in Baltic Sea Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8918-8927. [PMID: 34105953 DOI: 10.1021/acs.est.1c02136] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A strongly stratified water structure and a densely populated catchment make the Baltic Sea one of the most polluted seas. Understanding its circulation pattern and time scale is essential to predict the dynamics of hypoxia, eutrophication, and pollutants. Anthropogenic 236U and 233U have been demonstrated as excellent transient tracers in oceanic studies, but unclear input history and inadequate long-term monitoring records limit their application in the Baltic Sea. From two dated Baltic sediment cores, we obtained high-resolution records of anthropogenic uranium imprints originating from three major human nuclear activities throughout the Atomic Era. Using the novel 233U/236U signature, we distinguished and quantified 236U inputs from global fallout (45.4-52.1%), Chernobyl accident (0.3-1.8%), and discharges from civil nuclear industries (46.1-54.3%) to the Baltic Sea. We estimated the total release of 233U (7-15 kg) from the atmospheric nuclear weapon testing and pinpointed the 233U peak signal in the mid-to-late 1950s as a potential time marker for the onset of the Anthropocene Epoch. This work also provides fundamental 236U data on Chernobyl accident and early discharges from civil nuclear facilities, prompting worldwide 233U-236U tracer studies. We anticipate our data to be used in a broader application in model-observation interdisciplinary research on water circulation and pollutant dynamics in the Baltic Sea.
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Affiliation(s)
- Mu Lin
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Jixin Qiao
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Xiaolin Hou
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Olaf Dellwig
- Department of Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde, IOW, 18119 Rostock, Germany
| | - Peter Steier
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Karin Hain
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Robin Golser
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Liuchao Zhu
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
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Zhu L, Hou X, Qiao J. Determination of low-level 135Cs and 135Cs/ 137Cs atomic ratios in large volume of seawater by chemical separation coupled with triple-quadrupole inductively coupled plasma mass spectrometry measurement for its oceanographic applications. Talanta 2021; 226:122121. [PMID: 33676676 DOI: 10.1016/j.talanta.2021.122121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 10/22/2022]
Abstract
Radioisotopes of cesium are powerful tracer for oceanographic studies. In this work, a novel method was developed for determination of ultra-low level 135Cs and 137Cs in seawater using triple-quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). Cesium was pre-concentrated from up to 45 L seawater samples using ammonium molybdophosphate (AMP) adsorption, following a selective leaching of cesium using Sr(OH)2. The cesium was further purified from interfering elements using AMP-PAN and cation-exchange chromatography. Sr(OH)2 leaching was found to be an effective approach for selective exchange of cesium from the AMP sorbent without dissolution, which avoids the problem of separation of huge amount of NH4+ and MoO42- in the following steps. The decontamination factors for barium and rubidium with the developed method were more than 4 × 107 and 800, respectively. The separated 135Cs and 137Cs were measured using ICP-MS/MS by employing N2O as reaction gas to further elimination of isobaric (i.e. 135Ba and 137Ba) and polyatomic ions interferences. A detection limit of 1.5 × 10-16 g L-1 for 135Cs in seawater was achieved. The concentrations of 135Cs in seawater from Baltic Sea, Danish straits and Roskilde Fjord were determined using the developed method to identify the sources of 135Cs, the water masses exchange in this region was investigated using 135Cs and 137Cs.
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Affiliation(s)
- Liuchao Zhu
- Technical University of Denmark, Department of Environmental Engineering, Risø Campus, Roskilde, DK-4000, Denmark
| | - Xiaolin Hou
- Technical University of Denmark, Department of Environmental Engineering, Risø Campus, Roskilde, DK-4000, Denmark.
| | - Jixin Qiao
- Technical University of Denmark, Department of Environmental Engineering, Risø Campus, Roskilde, DK-4000, Denmark
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Lin M, Qiao J, Hou X, Golser R, Hain K, Steier P. On the Quality Control for the Determination of Ultratrace-Level 236U and 233U in Environmental Samples by Accelerator Mass Spectrometry. Anal Chem 2021; 93:3362-3369. [DOI: 10.1021/acs.analchem.0c03623] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mu Lin
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Jixin Qiao
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Xiaolin Hou
- Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
| | - Robin Golser
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Karin Hain
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Peter Steier
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
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An unknown source of reactor radionuclides in the Baltic Sea revealed by multi-isotope fingerprints. Nat Commun 2021; 12:823. [PMID: 33547296 PMCID: PMC7865023 DOI: 10.1038/s41467-021-21059-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 01/11/2021] [Indexed: 11/25/2022] Open
Abstract
We present an application of multi-isotopic fingerprints (i.e., 236U/238U, 233U/236U, 236U/129I and 129I/127I) for the discovery of previously unrecognized sources of anthropogenic radioactivity. Our data indicate a source of reactor 236U in the Baltic Sea in addition to inputs from the two European reprocessing plants and global fallout. This additional reactor 236U may come from unreported discharges from Swedish nuclear research facilities as supported by high 236U levels in sediment nearby Studsvik, or from accidental leakages of spent nuclear fuel disposed on the Baltic seafloor, either reported or unreported. Such leakages would indicate problems with the radiological safety of seafloor disposal, and may be accompanied by releases of other radionuclides. The results demonstrate the high sensitivity of multi-isotopic tracer systems, especially the 233U/236U signature, to distinguish environmental emissions of unrevealed radioactive releases for nuclear safeguards, emergency preparedness and environmental tracer studies. Anthropogenic activities lead to the accumulation of radioactive substances in the environment. Here the authors use multi-isotopic fingerprints of uranium and iodine to discover a previously unknown source of reactor uranium in the Baltic Sea, likely sourced from a Swedish nuclear facility.
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Shao Y, Yang G, Zhang J, Luo M, Ma L, Xu D. Progress and Application on the Analysis of Anthropogenic Radionuclide 236U. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a21020074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shao Y, Yang G, Luo M, Xu D, Tazoe H, Yamada M, Ma L. Background and fingerprint characteristics of anthropogenic 236U and 137Cs in soil and road dust samples collected from Beijing and Zhangjiakou, China. CHEMOSPHERE 2021; 263:127909. [PMID: 32822937 DOI: 10.1016/j.chemosphere.2020.127909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
236U has attracted more attention as an environmental tracer in recent years. However, in-depth study of 236U in terrestrial environments is still rare in China. Data on 236U and 137Cs concentrations in soil and road dust samples collected from Beijing and Zhangjiakou, China were obtained to demonstrate the background and distinct characteristics of anthropogenic 236U and 137Cs. 236U and 137Cs were detected in the range of (1.10-7.90) × 107 atoms g-1 and below the method limits of detection to 5.30 Bq kg-1. A clear characteristic was observed in road dust, where 236U concentrations increased with decreasing of sample particle size. Soil samples showed an irregular characteristic, but the highest 236U concentrations were observed in particle size fraction of <0.053 mm in both samples. This phenomenon was caused by U chemical properties, higher specific surface areas and organic compounds in fine particles. Anthropogenic radionuclides fingerprint characteristics in <0.053 mm samples were specially discussed. 236U/238U atom ratios were detected in the range of (0.627-3.38) × 10-8. A weak correlation between anthropogenic 236U and natural U isotopes were observed. The intermediate correlation between 236U and 137Cs indicated somewhat distinct migration behavior of these two radionuclides in soil after release to the environment. The released amount of 236U from global fallout during the period of atmospheric nuclear weapons testing was roughly estimated to be 1300 ± 448 kg. These results could be used as fingerprint information for anthropogenic 236U migration behavior and tracer application in environment.
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Affiliation(s)
- Yang Shao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China; Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Guosheng Yang
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Min Luo
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Diandou Xu
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Hirofumi Tazoe
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - 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.
| | - Lingling Ma
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
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Wang Y, Hou X, Zhang W, Zhang L, Fan Y. Determination of ultra-low 236U in environment samples using ICP-MS/MS measurement and chemical separation. Talanta 2020; 224:121882. [PMID: 33379091 DOI: 10.1016/j.talanta.2020.121882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/04/2020] [Accepted: 11/07/2020] [Indexed: 11/19/2022]
Abstract
236U in the environment mainly originates from human nuclear activities. Based on the unique properties of uranium, 236U can be used as a powerful tracer for investigation of oceanographic and environmental processes. This requires sensitive measuement of 236U in various environmental samples. Due to the ultra-low radioactive level of 236U in the environment, its measurement is only possible by mass spectrometry. Because of the low atomic ratio of 236U/235U down to 10-7-10-5 in the environment, the interferences of 235U1H+ and peak tailings of 235U and 238U are critical challenges in the measurement of 236U by ICP-MS. This work developed a sensitive ICP-MS/MS method for measurement of ultra-low 236U by employing reaction cell technique and sequential quadrupole mass separators. By using 0.6 mL min-1 CO2 - 7 mL min-1 helium as collision/reaction gas to convert U+ and UH+ to UO+, the interferences of UH+ (UOH+/UO+ ratio) were significantly reduced to less than 2.4 × 10-7. A minimum detectable 236U/238U ratio of 3.0 × 10-10 was achieved, which is one order of magnitude better than reported values. By using collision focusing with helium in the reaction cell and APEX sample introduction system, the measurement sensitivity for 236U (236UO+) was improved to 7.5 × 106 cps ppb-1. In combination with an effective chemical separation of uranium from sample matrix and interferences using total borate fusion following extraction chromatography with UTEVA resin, a detection limit of 7.2 × 10-16 g g-1 for 236U was achieved. The developed method was verified by analysis of certified reference materials and by comparison with AMS measurement method. Soil samples collected from Northwest China were successfully analyzed. 236U/238U ratios down to 9 × 10-10 were measured in these samples, and the sources of 236U in different sits were discussed.
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Affiliation(s)
- Yanyun Wang
- Xi'an AMS Center, State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of AMS Technology and Application, Institute of Earth Environment, CAS, Xi'an, 710061, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaolin Hou
- Xi'an AMS Center, State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of AMS Technology and Application, Institute of Earth Environment, CAS, Xi'an, 710061, China; Technical University of Denmark, Department of Environment Engineering, Risø Campus, Building 204, Frederiksborgvej 399, Roskilde, 4000, Denmark; CAS Center of Excellence in Quaternary Science and Global Change, Xi'an, 710061, China; Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266061, China.
| | - Weichao Zhang
- Xi'an AMS Center, State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of AMS Technology and Application, Institute of Earth Environment, CAS, Xi'an, 710061, China
| | - Luyuan Zhang
- Xi'an AMS Center, State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of AMS Technology and Application, Institute of Earth Environment, CAS, Xi'an, 710061, China; CAS Center of Excellence in Quaternary Science and Global Change, Xi'an, 710061, China; Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266061, China
| | - Yukun Fan
- Xi'an AMS Center, State Key Laboratory of Loess and Quaternary Geology, Shaanxi Key Laboratory of AMS Technology and Application, Institute of Earth Environment, CAS, Xi'an, 710061, China
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Qiao J, Hain K, Steier P. First dataset of 236U and 233U around the Greenland coast: A 5-year snapshot (2012-2016). CHEMOSPHERE 2020; 257:127185. [PMID: 32497842 DOI: 10.1016/j.chemosphere.2020.127185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/18/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
We report the first combined dataset of 236U and 233U in the Greenland marine environment during the period of 2012-2016. Results are discussed in terms of time evolution and spatial distribution of 236U concentration, and atomic ratios of 236U/238U and 233U/236U. 236U concentrations along the Greenland coast are distributed within a relatively narrow range of (0.7-12.9) × 107 atom/L, corresponding to 236U/238U atomic ratios of (1.1-15.5) × 10-9. The 233U/236U atomic ratios obtained vary from 0.12 × 10-2 to 1.16 × 10-2, with the majority distributed in the range of (0.2-0.7) × 10-2. We applied 233U/236U and 236U/238U atomic ratios in a binary mixing model to identify possible 236U source terms. The results indicate that anthropogenic 236U and 233U in Greenland surface seawater originated from the direct global fallout (DGF) and the Sellafield and La Hague reprocessing plants (RP) is diluted by a third endmember, mostly likely natural ocean water (NOW), containing marginal 236U and 233U. A preliminary estimation of the source terms of 236U using 233U/236U atomic ratios indicate that, for both eastern and western Greenland seawater, contributions from global fallout (GF) constitute about 30% of 236U. The dominating source for 236U, i.e. 70 %, is associated to reactor 236U including discharges from RP and local reactor input in the Arctic Ocean.
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Affiliation(s)
- Jixin Qiao
- Department of Environmental Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | - Karin Hain
- VERA Laboratory, Faculty of Physics - Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Peter Steier
- VERA Laboratory, Faculty of Physics - Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
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Jaegler H, Gourgiotis A, Steier P, Golser R, Diez O, Cazala C. Pushing Limits of ICP-MS/MS for the Determination of Ultralow 236U/ 238U Isotope Ratios. Anal Chem 2020; 92:7869-7876. [PMID: 32370491 DOI: 10.1021/acs.analchem.0c01121] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Determination of uranium isotope ratios is of great expedience for assessing its origin in environmental samples. In particular, the 236U/238U isotope ratio provides a powerful tool to discriminate between the different sources of uranium (uranium ore, geochemical background, and uranium from anthropogenic activities). However, in the environment, this ratio is typically below 10-8. This low abundance of 236U and the presence in large excess of major isotopes (mainly 238U and 235U) complicates the accurate detection of 236U signal by mass spectrometry and thus highly sensitive analytical instruments providing high abundance sensitivity are required. This work pushes the limits of triple quadrupole-based ICP-MS technology for accurate detection of 236U/238U isotope ratios down to 10-10, which is so far mainly achievable by AMS. Coupled with an efficient desolvating module, N2O was used as the reaction gas in the collision reaction cell of the ICP-MS/MS. This configuration allows a significant decrease of the uranium polyatomic interferences (235UH+ ions) and an accurate determination of low 236U/238U isotope ratios. This new methodology was successfully validated through measurements of certified reference material from 10-7 to 10-9 and then through comparisons with AMS measurement results for ratios down to 10-10. This is the first time that 236U/238U isotope ratios as low as 10-10 were determined by ICP-MS/MS. The possibility of measuring low 236U/238U isotope ratios can offer a large variety of geochemical applications in particular for the determination of uranium sources in the environment.
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Affiliation(s)
- Hugo Jaegler
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, 31 Avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France
| | - Alkiviadis Gourgiotis
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, 31 Avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France
| | - Peter Steier
- University of Vienna, Faculty of Physics, Isotope Research and Nuclear Physics, Vienna Environmental Research Accelerator, Währinger Straße 17, 1090 Vienna, Austria
| | - Robin Golser
- University of Vienna, Faculty of Physics, Isotope Research and Nuclear Physics, Vienna Environmental Research Accelerator, Währinger Straße 17, 1090 Vienna, Austria
| | - Olivier Diez
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, 31 Avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France
| | - Charlotte Cazala
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, 31 Avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France
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15
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Qiao J, Andersson K, Nielsen S. A 40-year marine record of 137Cs and 99Tc transported into the Danish Straits: Significance for oceanic tracer studies. CHEMOSPHERE 2020; 244:125595. [PMID: 32050355 DOI: 10.1016/j.chemosphere.2019.125595] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/25/2019] [Accepted: 12/08/2019] [Indexed: 06/10/2023]
Abstract
This work reports comprehensive time-series datasets for 137Cs and 99Tc in marine samples from the Danish Straits over the past 40 years, where dynamic inputs from the two European nuclear reprocessing plants Sellafield (SF) and La Hague (LH) and Chernobyl accident are clearly archived. Distinct seasonal variations between 137Cs and 99Tc are observed in Fucus vesiculosus (F. vesiculosus), which needs to be taken into account when using F. vesiculosus as a bio-monitor to represent the concentration of radionuclides in seawater. Comparable transfer factor (TF) for 99Tc from SF to Kattegat between our calculation and earlier studies indicates a relatively steady water mass transport over the past decades. Three distinct events are observed in the temporal evolution of 99Tc/137Cs activity ratio in F. vesiculosu with the first event corresponding with the increased 99Tc discharge from SF, while the other two are very likely related to the major Baltic inflow (MBI) events. The correlation between the 99Tc/137Cs activity ratio and salinity fits well into the binary mixing line with the North Sea (NS) and the Baltic Sea (BS) as end members. A model simulation indicates that water mass from NS constitutes less than 50% in the surface water and 50-100% for most locations in the bottom water of the Danish Straits. Overall observations show that 137Cs and 99Tc in marine samples, especially 99Tc/137Cs isotope ratios, serve as useful oceanic tracers to study different natural processes, such as water mixing and transport dynamics.
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Affiliation(s)
- Jixin Qiao
- Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, DK-4000, Roskilde, Denmark.
| | - Kasper Andersson
- Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, DK-4000, Roskilde, Denmark
| | - Sven Nielsen
- Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, DK-4000, Roskilde, Denmark
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16
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233U/ 236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout. Nat Commun 2020; 11:1275. [PMID: 32152279 PMCID: PMC7062840 DOI: 10.1038/s41467-020-15008-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/13/2020] [Indexed: 11/09/2022] Open
Abstract
Isotopic ratios of radioactive releases into the environment are useful signatures for contamination source assessment. Uranium is known to behave conservatively in sea water so that a ratio of uranium trace isotopes may serve as a superior oceanographic tracer. Here we present data on the atomic [Formula: see text]U/[Formula: see text]U ratio analyzed in representative environmental samples finding ratios of (0.1-3.7)[Formula: see text]10[Formula: see text]. The ratios detected in compartments of the environment affected by releases of nuclear power production or by weapons fallout differ by one order of magnitude. Significant amounts of [Formula: see text]U were only released in nuclear weapons fallout, either produced by fast neutron reactions or directly by [Formula: see text]U-fueled devices. This makes the [Formula: see text]U/[Formula: see text]U ratio a promising new fingerprint for radioactive emissions. Our findings indicate a higher release of [Formula: see text]U by nuclear weapons tests before the maximum of global fallout in 1963, setting constraints on the design of the nuclear weapons employed.
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Direct measurement of uranium in seawater by inductively coupled plasma mass spectrometry. Talanta 2018; 183:18-23. [DOI: 10.1016/j.talanta.2018.02.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 11/17/2022]
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18
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Development and application of mass spectrometric techniques for ultra-trace determination of 236U in environmental samples-A review. Anal Chim Acta 2017; 995:1-20. [DOI: 10.1016/j.aca.2017.09.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/23/2017] [Accepted: 09/19/2017] [Indexed: 02/04/2023]
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Christl M, Casacuberta N, Lachner J, Herrmann J, Synal HA. Anthropogenic 236U in the North Sea - A Closer Look into a Source Region. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12146-12153. [PMID: 28990772 DOI: 10.1021/acs.est.7b03168] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study we present new seawater data of 236U and 238U sampled in the North Sea in 2010. The North Sea has been and is still receiving a considerable input of anthropogenic radionuclides from nuclear reprocessing facilities located in La Hague (France) and Sellafield (Great Britain). It therefore represents an important source region for oceanographic tracer studies using the transient signal of anthropogenic 236U. A proper knowledge of the sources of 236U is an essential prerequisite for such tracer studies. The 236U data set presented in this study covers the transition regions of the North Sea to the Atlantic Ocean, to the Baltic Sea, and upstream the Elbe River. It is discussed in the context of available 236U data from the literature. Our results show that both 236U concentrations and 236U/238U ratios in surface waters of the North Sea can be explained by simple binary mixing models implying that 236U behaves conservatively in seawater. We further show that the input of 236U by the Elbe River is negligible, while there might be a maximum input of 12 g/yr via the Baltic Sea. The results of the mixing models suggest that this still unidentified 236U contamination could be supplied by fresh water input.
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Affiliation(s)
| | | | | | - Jürgen Herrmann
- Bundesamt für Seeschifffahrt und Hydrographie, 22589 Hamburg, Germany
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