1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Guan YJ, He H, Fan KD, Wang SZ, Guo ZC, Wang HJ, Cui LJ, Chen W, Huang CP, Liu ZY, He XW, Guo KX, Zhang JJ, Xu ZY. Spatial distribution, source identification, and transportation paths of plutonium in the Beibu Gulf, South China Sea. MARINE POLLUTION BULLETIN 2024; 199:115972. [PMID: 38154170 DOI: 10.1016/j.marpolbul.2023.115972] [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: 10/30/2023] [Revised: 12/12/2023] [Accepted: 12/21/2023] [Indexed: 12/30/2023]
Abstract
To investigate the spatial distribution and source of plutonium isotopes in the Beibu Gulf, surface sediments were collected and analyzed using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). The activities of 239+240Pu in surface sediments ranged from 0.012 to 0.451 mBq/g (mean: 0.171 ± 0.138 mBq/g, n = 36), indicating a decreasing trend in a counterclockwise direction from the southern bay mouth. The counterclockwise decreasing trend in the south of the bay mouth is similar to the current in the Beibu Gulf. The 240Pu/239Pu atom ratios in surface sediments ranged from 0.156 to 0.283 (mean: 0.236 ± 0.031, n = 36), slightly higher than that of the global fallout value of 0.18. This suggests that the Pu in the Beibu Gulf was a combination of global fallout and Pacific Proving Ground (PPG). The average contribution of the plutonium (Pu) derived from the PPG in the sediment was estimated to be 52 % ± 24 %.
Collapse
Affiliation(s)
- Yong-Jing Guan
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Hua He
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Kai-di Fan
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Shen-Zhen Wang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Zi-Chen Guo
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Hui-Juan Wang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Liang-Jia Cui
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Wu Chen
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Chun-Ping Huang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Zhi-Yong 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.
| | - Xian-Wen He
- Radiation-Environment Management and Monitoring Station of Guangxi Zhuang Autonomous Region, Guangxi, Nanning 530222, China
| | - Kai-Xing Guo
- Radiation-Environment Management and Monitoring Station of Guangxi Zhuang Autonomous Region, Guangxi, Nanning 530222, China
| | - Jia-Jia Zhang
- Radiation-Environment Management and Monitoring Station of Guangxi Zhuang Autonomous Region, Guangxi, Nanning 530222, China
| | - Ze-Yue Xu
- Radiation-Environment Management and Monitoring Station of Guangxi Zhuang Autonomous Region, Guangxi, Nanning 530222, China
| |
Collapse
|
3
|
Chen J, Wang C, Wu J, Tao S. Plutonium in sediments of the Eastern Guangdong coast-its sources and their contribution. MARINE POLLUTION BULLETIN 2023; 193:115222. [PMID: 37406399 DOI: 10.1016/j.marpolbul.2023.115222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/07/2023]
Abstract
The 239+240Pu activities and 240Pu/239Pu atom ratios of surface sediments from the Eastern Guangdong coast (EGDC) were determined by sector field ICP-MS in order to examine the sources of plutonium (Pu) and quantify their contributions. The 239+240Pu activities in the EGDC ranged from 0.113 to 0.451 Bq kg-1, with an average of 0.225 ± 0.090 Bq kg-1 (n = 17). Consistently high 240Pu/239Pu atom ratios, ranging from 0.218 to 0.274 (average = 0.254 ± 0.014, n = 17), indicate a non-global fallout Pu source in the EGDC. The horizontal distribution of the 240Pu/239Pu atom ratios in the EGDC sediment suggests the non-global fallout Pu is sourced from close-in fallout from the Pacific Proving Grounds (PPG). Using a simple two end-member mixing model, we calculated the relative proportions of Pu from the PPG and global fallout in the EGDC to be 57 ± 9 % and 43 ± 9 %, respectively. Moreover, from the well-defined relationship between 239+240Pu activity and total organic carbon content in sediments and a two end-member mixing model using δ13C, we further calculated the Terr-global fallout (riverine input) and Mar-global fallout (direct atmospheric deposition) to be 11 ± 2 % and 32 ± 6 %, respectively. Finally, from the activity levels and atom ratios of Pu isotopes in the EGDC, we established a baseline for future use in environmental risk assessment related to nuclear power plant operations.
Collapse
Affiliation(s)
- Jisheng Chen
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention & Institute of Marine Sciences, Shantou University, Shantou 515063, China
| | - Cui Wang
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen 361005, China
| | - 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), Guangzhou 511458, China.
| | - Shuqin Tao
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen 361005, China
| |
Collapse
|
4
|
Lukashenko SN, Edomskaya MA. Plutonium in the Environment: Sources, Dissemination Mechanisms, and Concentrations. BIOL BULL+ 2022. [DOI: 10.1134/s1062359022110139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
|
5
|
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]
|
6
|
Huang Y, Sun X, Zhang W. Spatio-temporal distribution of 239+240Pu in sediments of the China sea and adjacent waters. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 253-254:107010. [PMID: 36108554 DOI: 10.1016/j.jenvrad.2022.107010] [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: 12/23/2021] [Revised: 08/23/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Data of 239+240Pu activities and 240Pu/239Pu atom ratios in surface and core sediments of the China Sea and adjacent waters were collected. We examine a dataset of 239+240Pu activities and 240Pu/239Pu ratios determined from surface sediments at 516 sites and 84 core sediment mainly across the China Sea and adjacent waters. For the first time the spatial distributions of the 239+240Pu activities, the 240Pu/239Pu ratios and the Pacific Proving Ground (PPG) fraction in the China Sea and adjacent waters are fully presented at the same time. Four types of typical 239+240Pu distribution with depth are commonly summarized: non-peak, pseudo single peak, single peak and multi peaks, which are based on the comprehensive analysis of the vertical distribution of 239+240Pu in 84 sediment cores that had been studied in the China Sea and adjacent waters. Their occurrence probability are ∼15%, ∼4%, ∼67% and ∼11%, respectively. This is the dominant Pu source in seawater which was transported by the North Equatorial Current and Kuroshio Current and its extension into the China Sea and adjacent waters first from east to west, then from south to north. A sea area to the northeast of Taiwan Island and the Okinawa Trough, shows high 239+240Pu activities and 240Pu/239Pu atom ratios spatial distribution trends, which are related to the intrusion of the Kuroshio Current carrying 239+240Pu from the PPG nuclear weapon tests. The used two end-member mixing model suggests that global fallout and PPG close-in fallout are the main sources of Pu in most of the investigate areas. As the 240Pu/239Pu of global fallout is relatively constant, the change of 240Pu/239Pu ratios in surface sediments of the China Sea and adjacent waters are mainly controlled by the PPG close-in fallout input.
Collapse
Affiliation(s)
- Yanan Huang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, PR China; Centre Nacional de Aceleradores (CNA),Sevilla, 41092, Spain.
| | - Xiaoming Sun
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, PR China.
| | - Wei Zhang
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, 08540-6654, USA
| |
Collapse
|
7
|
Chen CTA, Huang TH, Huang WJ, Yang YJ, Jan S, Lee MA, Lee MT. The Kuroshio radiocesium stream. MARINE POLLUTION BULLETIN 2022; 182:114026. [PMID: 35963224 DOI: 10.1016/j.marpolbul.2022.114026] [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: 04/07/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
The Fukushima accident released short-lived Cs-134 and longer-lived Cs-137 to the ocean. The amount, although substantial, is much less than that produced during the atomic bomb tests 60 years ago. But, the latter has received little attention. Here we found only Cs-137 in waters near the origin of the Kuroshio. The speed of the Kuroshio current generally decreases with water depth, yet, the Cs-137 activity increases with depth to reach a subsurface maximum of 2.4 Bq m-3. As a result, a core of high Cs-137 flux, or a radiocesium stream, exists at approximately 200-400 m in depth. In total, the Kuroshio transports about 1 PBq year-1 Cs-137 northward between 121 and 123°E, 1000 times more than the 0.73-1.0 TBq year-1 discharged to the ocean at Fukushima in 2016-2018.
Collapse
Affiliation(s)
| | - Ting-Hsuan Huang
- Taiwan Ocean Research Institute, National Applied Research Laboratories, Kaohsiung 801, Taiwan
| | - Wei-Jen Huang
- Department of Oceanography, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yiing-Jang Yang
- Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan
| | - Sen Jan
- Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan
| | - Ming-An Lee
- Department of Environmental Biology and Fisheries Science, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Ming-Ta Lee
- Radiation Monitoring Center, Atomic Energy Council, Kaohsiung 833, Taiwan
| |
Collapse
|
8
|
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.
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Wang F, Zheng J, Aono T, Pan S, Men W. Source and distribution characteristics of 239, 240, 241Pu, 237Np and 134, 137Cs in sediments in the Northwest and Central Equatorial Pacific after the Fukushima nuclear accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 304:119214. [PMID: 35358631 DOI: 10.1016/j.envpol.2022.119214] [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: 10/09/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
To understand the possible influence of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on the deep sea, as well as the geochemical behavior and transport of radionuclides, 134Cs, 137Cs, 239, 240Pu, 241Pu, and 237Np were measured in the abyssal sediments of the Northwest Pacific (NWP) and Central Equatorial Pacific (CEP) Ocean. Data on the characteristics of these sediments obtained after the FDNPP accident are extremely rare, especially in the NWP subtropical gyre (NPSG) region. FDNPP-derived radio-Cs (134Cs, 137Cs) arrived at the open sea floor of the NWP before 2018 but was only found in the Kuroshio-Oyashio Extension (KOE) region. No FDNPP-derived Pu was detected in the abyssal sediments of the NWP or CEP. Pu in the NWP mainly originated from global fallout and the Pacific Proving Ground (PPG) close-in fallout, except for at station WP1 (39°N in the KOE region), where an abnormal but non-FDNPP-derived Pu signal was detected. Pu in the eastern CEP sediment was less affected by the PPG close-in fallout from the Marshall Islands and was mainly derived from global fallout, with some close-in fallout from the Johnston Atoll test. The KOE region was the area most affected by PPG close-in fallout Pu via Kuroshio transport, while the lowest inventories of 239+240Pu and 237Np were found in the NPSG region due to its oligotrophic environment. The 237Np originated from the same source as Pu, and the latitudinal pattern of 237Np was consistent with that of Pu. Station SS (in the marginal sea of the NWP) contained high 237Np/239Pu atom ratios in the deeper layers of sediment and had a 237Np depth profile opposite that of the 239+240Pu profile, compared to other stations; these differences are mainly attributed to differences in the behaviors of 237Np and 239Pu.
Collapse
Affiliation(s)
- Fenfen Wang
- The Key Laboratory of Coastal and Island Development of the Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, 210023, China; Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan; The Laboratory of Marine Ecological Environment Early Warning and Monitoring, Third Institute of Oceanography, Ministry of Natural Resources, P.R.C, Xiamen, 361005, China
| | - Jian Zheng
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.
| | - Tatsuo Aono
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Shaoming Pan
- The Key Laboratory of Coastal and Island Development of the Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, 210023, China
| | - Wu Men
- The Laboratory of Marine Ecological Environment Early Warning and Monitoring, Third Institute of Oceanography, Ministry of Natural Resources, P.R.C, Xiamen, 361005, China
| |
Collapse
|
11
|
Hirose K, Povinec PP. Temporal variability of plutonium in surface waters of the Sea of Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 248:106890. [PMID: 35477137 DOI: 10.1016/j.jenvrad.2022.106890] [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: 01/12/2022] [Revised: 04/04/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
Long-term temporal variations of plutonium in Sea of Japan (SOJ) surface waters have been examined with the aim to better understand its behavior during several decades. The first observation is that 239,240Pu activity concentrations in surface waters of the SOJ during 1977-2019 were 6.5 ± 4.7 mBq m-3 in average, and 5.1 mBq m-3 as the median, whereas 137Cs and 90Sr activity concentrations decreased with time, except of the perturbation due to the 2011 Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Another observation is that sporadic high 239,240Pu activity concentrations occurred in the east Japan Basin, ranging from 1 to 39 mBq m-3. The spatial distribution of 239,240Pu activity concentrations in surface waters revealed that high 239,240Pu levels (>20 mBq m-3) occurred in 1994 in the northern SOJ, which was considered to be due to winter convection. To elucidate factors controlling the temporal variability of surface 239,240Pu levels in the SOJ, a relationship between surface 239,240Pu activity concentrations and vertical diffusion coefficients was examined. The results revealed that this relationship could be classified into two groups: one group did not show a change with increasing diffusion coefficient, while the other group showed a positive correlation. The vertical 239,240Pu distribution in SOJ waters suggests that the high surface 239,240Pu levels occurred due to the upwelling of cyclonic eddy. The rapid recycling of deeper plutonium occurred in the SOJ due to deep winter convection and upwelling associated with cyclonic eddy. The plutonium levels in the SOJ have been found to be sensitive to climate changes. Warming of the SOJ may cause a reduction of winter convection and eddy activity as a result of increasing sea surface temperature. This leads to a decline of recirculation of plutonium and other bioavailable elements from Japan Sea Proper Water (JSPW) to surface water layers. Plutonium would be, therefore, an important indicator of biogeochemical processes in the marine environment, helping to assess climate change impacts on marine ecological systems.
Collapse
Affiliation(s)
- Katsumi Hirose
- Laboratory for Environmental Research at Mount Fuji, Okubo, Shinjyuku-ku, Tokyo, Japan.
| | - Pavel P Povinec
- Comenius University, Department of Nuclear Physics and Biophysics, Bratislava, Slovakia
| |
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Wang R, Mai J, Guan Y, Liu Z. Radionuclides in the environment around the uranium mines in Guangxi, China. Appl Radiat Isot 2020; 159:109098. [PMID: 32250770 DOI: 10.1016/j.apradiso.2020.109098] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 01/02/2020] [Accepted: 02/23/2020] [Indexed: 11/30/2022]
Abstract
Uranium and plutonium are both poisonous radioactive elements, which are very harmful to human health and environment. Therefore, it is of great significance to study the distribution of 238U concentration and 239+240Pu activity in the uranium mine surrounding soils. We have collected some surface soil sediments within 2 km of two uranium mines and a solid waste management center in Guangxi Province. The 238U concentration in these study areas is in the range of 1.44-83.91 mg/g, and the 238U concentration in the A uranium mine surrounding surface soils is higher than that in the B uranium mine and the solid waste management center. While the B uranium mine and the solid waster management center don't pollute the surrounding soils because the 238U concentrations in their surrounding soils are similar to the average 238U concentration in the soil. The 239+240Pu activities in soil samples collected around the two uranium mines and the solid waste management center are close ranged from 0.06 mBq/g to 0.51 mBq/g. Moreover, the 240Pu/239Pu atom ratios in our study samples are ranged from 0.15 to 0.23, which indicate the Pu may come from the global fallout. In addition, we study heavy metals in our collected samples, only heavy metal Tl has weak positive correlations with 238U concentrations and 239+240Pu activities. And there is a weak positive correlation between 238U concentrations and 239+240Pu activities.
Collapse
Affiliation(s)
- Ruirui 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
| | - Jingyu Mai
- 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
| | - Yongjin Guan
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, 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.
| |
Collapse
|
18
|
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Wang R, Fu Y, Lei L, Li G, Liu Z. Distribution and Source Identification of Pu in River Basins in Southern China. ACS OMEGA 2019; 4:22646-22654. [PMID: 31909349 PMCID: PMC6941367 DOI: 10.1021/acsomega.9b03650] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/09/2019] [Indexed: 05/26/2023]
Abstract
The 239+240Pu activities and 240Pu/239Pu atom ratios in surface sediments from the major river basins in southern China were analyzed to investigate the distribution and source of Pu. We clarified that the 239+240Pu activities in these river basins were very similar, however, only the 239+240Pu activities in the Jinjiang Basin were generally higher than other samples. Because of river transport function, the distribution of 239+240Pu activities in these river basins presented an increasing trend from the upstream region to the estuary. According to the 240Pu/239Pu atom ratios, the Pu source in the inner river basins might be from global fallout, and the Pu in river estuaries might be from the global fallout and the Pacific Proving Grounds (PPG) in the Marshall Islands. Using a mass balance of the Pu model, we quantified in the Pearl River Estuary and the Pu contribution from the Pearl River Basin to Pu inventory was 13 ± 5%. These data not only filled in a knowledge gap of Pu in these river basins but also served as background data for Pu contamination from a nuclear reactor. Also, there are several planned and operating nuclear power plants in these river basins and these data could provide some indications for dealing with nuclear accidents in different parts of river basins in the future. In this study, we also analyzed some factors that would affect the distribution of 239+240Pu activities; however, only total organic carbon (TOC) content and the heavy metal As had a positive correlation with the 239+240Pu activity.
Collapse
Affiliation(s)
- Ruirui 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
| | - Yao Fu
- 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
| | - Ling Lei
- 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
| | - Gang Li
- Key
Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, Guangzhou 510300, 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
| |
Collapse
|
21
|
Wu J. Isotopic composition and source of plutonium in the Qinghai-Tibet Plateau frozen soils. Sci Rep 2019; 9:7861. [PMID: 31133665 PMCID: PMC6536505 DOI: 10.1038/s41598-019-44391-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 05/16/2019] [Indexed: 11/10/2022] Open
Abstract
The 239+240Pu activities and 240Pu/239Pu atom ratios in the frozen soils of the Yellow River Source Area (YRSA) were determined to examine the Pu source and evaluate its environmental risk. The 239+240Pu activities of surface frozen soils in the YRSA, ranging from 0.053 to 0.836 mBq g-1, are comparable to those observed in China elsewhere (0.005-1.990 mBq g-1). The 240Pu/239Pu atom ratios of surface soils in the YRSA are in the range of 0.168-0.201 (average = 0.187 ± 0.012, n = 6), comparable to the global fallout of 0.180 ± 0.014. Based on the latitudinal and spatial distribution of Pu isotopic composition, I clarified that the Pu source is mainly from global fallout at present. The activity levels of Pu in the YRSA do far not cause a Pu toxicity to the downstream drinking water even the frozen soil begins to melt and release Pu to the Yellow River. However, since close-in fallout from Lop Nor where the Chinese nuclear tests were carried out during 1964-1980, high deposition and accumulation of Pu was observed in the Chinese soil cores through synthesizing an expanded Pu dataset, which alerts us it is necessary to further monitor the Pu activity levels in the YRSA soil cores to ensure the safety of downstream drinking water. Finally, I point out that information on Pu isotopes would help in establishing a baseline for future environmental risk assessment.
Collapse
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, 361102, Xiamen, China.
| |
Collapse
|
22
|
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%.
Collapse
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
| |
Collapse
|
23
|
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.
Collapse
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.
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Lee SH, Oh JS, Lee KB, Lee JM, Hwang SH, Lee MK, Kwon EH, Kim CS, Choi IH, Yeo IY, Yoon JY, Im JM. Evaluation of abundance of artificial radionuclides in food products in South Korea and sources. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 184-185:46-52. [PMID: 29334620 DOI: 10.1016/j.jenvrad.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 06/07/2023]
Abstract
Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.
Collapse
Affiliation(s)
- S H Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
| | - J S Oh
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - K B Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - J M Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - S H Hwang
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - M K Lee
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - E H Kwon
- Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - C S Kim
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - I H Choi
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - I Y Yeo
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - J Y Yoon
- Korea Institute of Nuclear Safety, Daejeon, 34142, Republic of Korea
| | - J M Im
- Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea
| |
Collapse
|
26
|
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.
Collapse
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.
| |
Collapse
|