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Wang H, Ni Y, Men W, Wang Z, Liu M, Xiao D, Zheng J. Distributions of fallout 137Cs, 239+240Pu and 241Am in a soil core from South Central China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106971. [PMID: 35961100 DOI: 10.1016/j.jenvrad.2022.106971] [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: 09/01/2021] [Revised: 06/16/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
The source and vertical distribution of 137Cs,239+240Pu and 241Am activity concentrations in a soil core from Hunan Province, China were investigated. The maximum 137Cs and 239+240Pu activity concentrations were 15.45 ± 0.76 mBq/g and 0.819 ± 0.066 mBq/g, respectively. While the maximum 241Am activity concentration in samples obtained from the core was 0.341 ± 0.019 mBq/g. The 240Pu/239Pu atom ratio and the 137Cs/239+240Pu activity ratio were 0.183 ± 0.011 and 19.5 ± 1.8, respectively, and both were consistent with the characteristic value of global fallout. The integrated 241Am/239+240Pu activity ratio for global fallout was also re-estimated. The measured 241Am/239+240Pu activity ratio (average 0.43 ± 0.07) in the samples was very close to the estimated value (0.45), which suggested their 241Am also came from the global fallout. Regarding the vertical distribution of 137Cs, 239+240Pu and 241Am in these red soil samples, all these radionuclides had higher concentrations in upper layers of several centimeters of soil while they had slightly lower concentrations in lower soil layers down to 30 cm. Vertical distributions of 137Cs/239+240Pu and 241Am/239+240Pu activity ratios indicated the migration velocity was Am ≈ Pu > Cs. The intrinsic chemical properties of the radionuclides as well as soil type and properties (acidic, nutrient-deficient and low in organic matter and cation exchange capacity) might be reasons for the differences in their migration behaviors.
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Affiliation(s)
- Hai Wang
- School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China; National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.
| | - Youyi Ni
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
| | - Wu Men
- School of Marine Sciences, Nanjing University of Information Science & Technology, Ningliu Road, Nanjing, Jiangsu, 210044, China
| | - Zhongtang Wang
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
| | - Min Liu
- School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China
| | - Detao Xiao
- School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China
| | - Jian Zheng
- National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.
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Sources and Variability of Plutonium in Chinese Soils: A Statistical Perspective with Moving Average. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
We investigated the different sources and their corresponding impact areas of Pu in Chinese surface soils to illustrate the state-of-the-art of the sources, levels and distributions of 240Pu/239Pu atom ratios as well as 239+240Pu activity concentrations in China. For the first time a moving average strategy in combination with statistical analysis was employed to partition geographic areas in China based on the reported 240Pu/239Pu atom ratio and 239+240Pu concentration data from public literature. During the partitioning, the median (MED) of the dataset was basically employed as a criteria in place of the commonly used arithmetic average (AM). Concisely, three areas were partitioned according to the different influences of Pu from the Lop Nor (LNTS) and Semipalatinsk (STS) test sites and the global fallout. The partitioned Ternary area (80° E–105° E, 35° N–50° N) was supposed to have multiple sources of Pu including the STS and LNTS besides the global fallout, which was characterized with slightly lower 240Pu/239Pu atom ratios (MED = 0.174) as well as elevated 239+240Pu concentrations (MED = 0.416 mBq/g). Meanwhile, the Binary area (35° N–45° N, 100° E–115° E) was considered to have received the extra contribution from the high-yield nuclear tests at the LNTS besides the global fallout, resulting in the highest 240Pu/239Pu atom ratios (MED = 0.200) across China. The remaining area was marked as the Unitary area, where it only received the exclusive contribution of global fallout. Furthermore, through the statistical analysis of the 240Pu/239Pu data in the Unitary area, we recommended a value of 0.186 ± 0.021 (AM ± SD) as a representative or area-specific 240Pu/239Pu atom ratio baseline to characterize the global fallout derived Pu in Chinese soils.
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Guan Y, Zhang P, Huang C, Wang D, Wang X, Li L, Han X, Liu Z. Vertical distribution of Pu in forest soil in Qinghai-Tibet Plateau. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 229-230:106548. [PMID: 33581482 DOI: 10.1016/j.jenvrad.2021.106548] [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: 10/28/2020] [Revised: 01/23/2021] [Accepted: 01/30/2021] [Indexed: 06/12/2023]
Abstract
The 239+240Pu and 137Cs activities and 240Pu/239Pu atom ratios in surface soil and soil core collected from Qinghai-Tibet Plateau were investigated. The maximum of 239+240Pu and 137Cs activity concentrations in five soil cores were found in upper layers and have a same trend: the maximum followed by exponential decline. The 240Pu/239Pu atom ratio ranged from 0.160 ± 0.009 to 0.212 ± 0.012, clarified that the plutonium mainly came from the global fallout and the contribution of Lop Nor test sites was negligible. In addition, the vertical profiles of radionuclides (210Pb, 238U, 232Th, 226Ra, 40K) have been studied and a high correlation has been found between them. The correlations of Pu between organic matter (OM) and heavy metals were also studied. Person Correlation Coefficients revealed Pu had significant positive correlations with organic matter and Cd, Cu, Co, Zn, but negative correlation with Tl. The results have important implication for further understanding of the sources, records and environmental impacts of global and regional nuclear activities, which expanded the database of Pu activity level and atom ratio in Chinese soil and established a foundation for future environmental risk assessment.
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Affiliation(s)
- Yongjin Guan
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Peijun Zhang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China; 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
| | - Chunping Huang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China; 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
| | - Deyu Wang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Xianggao Wang
- Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
| | - Longqing Li
- 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
| | - Xiaoxiao Han
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China.
| | - Zhiyong Liu
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China.
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Wu J, Sun J, Xiao X. An overview of current knowledge concerning the inventory and sources of plutonium in the China Seas. MARINE POLLUTION BULLETIN 2020; 150:110599. [PMID: 31733905 DOI: 10.1016/j.marpolbul.2019.110599] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 06/10/2023]
Abstract
This study reviews the current understanding of the inventory and sources of plutonium (Pu) in the marine environment adjacent to China. The 239+240Pu inventory in the China Seas was found to have large spatial variations. The quantity in sediments decreases away from the shore, generally tracing the sedimentation rate distribution. High 239+240Pu inventories indicated that Pu in the water column was easily scavenged since Pu has a high particle affinity. Indeed, substantially higher 240Pu/239Pu atom ratios were observed in the sediment and seawater of the China Seas than are found in global fallout. We thus clarified that Pu sources in the China Seas were from both global fallout and the Pacific Proving Grounds (PPG) in the Pacific Marshall Islands. Plutonium from the latter source is transported into the China Seas through the North Equatorial Current (NEC) and Kuroshio. Using a two end-member mixing model, we revealed that the contribution of Pu from the PPG accounts for over 40% of the Pu in the East China Sea (ECS) and South China Sea (SCS), and less than 20% of the Pu in the Yellow Sea (YS). The distributions and isotopic composition of Pu in the China Seas indicate strong scavenging of Pu in the ECS and high Pu accumulation in the SCS. This information on the inventory and isotopic composition of Pu helps to establish a background for the future study of Pu in the China Seas.
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Affiliation(s)
- Junwen Wu
- College of Science, Shantou University, Shantou, 515063, China.
| | - Jiang Sun
- College of Science, Shantou University, Shantou, 515063, China
| | - Xiyu Xiao
- College of Science, Shantou University, Shantou, 515063, China
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