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Li P, Sun Q, Cong L. Study on the influence of water saturation on radon exhalation rates of rocks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174192. [PMID: 38914332 DOI: 10.1016/j.scitotenv.2024.174192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/19/2024] [Accepted: 06/20/2024] [Indexed: 06/26/2024]
Abstract
The radon exhalation characteristics of rocks will change significantly during water saturation treatment, and radon, as an important tracer, is of great significance in predicting rock activities. In this paper, the radon exhalation characteristics of rocks after saturated with different water contents were studied by centrifugal test, radon measurement test and other indoor tests. The results show that the radon exhalation rate of rocks shows a rising and then decreasing trend with the increase of rock water saturation. The radon precipitation rate peaked at 0.7 Sw ∼ 0.8 Sw, and the high water saturation had an obvious inhibiting effect on the radon exhalation rate of rocks. The research results are of great significance in predicting the rock-water-based geological processes.
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Affiliation(s)
- Pengfei Li
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Qiang Sun
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, 710054, China; Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources, China.
| | - Lin Cong
- CCTEG Xi'an Research Institute (Group) Co., Ltd, Xi'an, Shaanxi 710077, China
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Li P, Sun Q, Geng J, Jing X, Tang L. Study on the characteristics of radon exhalation from rocks in coal fire area based on the evolution of pore structure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160865. [PMID: 36521600 DOI: 10.1016/j.scitotenv.2022.160865] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/12/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Radon is of great significance as a tracer for the detection of coal fires due to its distinct variations in radon exhalation properties while heating. The research on radon exhalation performance through pore structure is still in its early stages. In this paper, the pore structure and radon exhalation characteristics of heat-treated limestone are studied using indoor tests such as nuclear magnetic and radon measurements. The study's results demonstrate that the radon exhalation rate of limestone initially increases gradually, followed by a steady decline and subsequent increase with the increase in temperature. The radon exhalation rate at 800 °C reaches 2.42 times that at room temperature. The pore structure change within limestone strongly correlates with the radon exhalation rate. The pore volume of micropores (<0.1 μm) plays an essential role in the radon exhalation capacity, which is directly related to the fractal dimension of micropore structure in the heated limestone. The study's findings can be used to identify coal fires.
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Affiliation(s)
- Pengfei Li
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Qiang Sun
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, 710054, China; Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources, China.
| | - Jishi Geng
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Xudong Jing
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Liyun Tang
- College of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
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Sakoda A, Ishida T, Kanzaki N, Tanaka H, Kataoka T, Mitsunobu F, Yamaoka K. Radon Solubility and Diffusion in the Skin Surface Layer. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19137761. [PMID: 35805423 PMCID: PMC9265964 DOI: 10.3390/ijerph19137761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 06/18/2022] [Indexed: 12/10/2022]
Abstract
In specific situations such as bathing in a radon spa, where the radon activity concentration in thermal water is far higher than that in air, it has been revealed that radon uptake via skin can occur and should be considered for more precise dose evaluation. The primary aim of the present study was to numerically demonstrate the distribution as well as the degree of diffusion of radon in the skin, with a focus on its surface layer (i.e., stratum corneum). We developed a biokinetic model that included diffusion theory at the stratum corneum, and measured radon solubility in that tissue layer as a crucial parameter. The implementation of the model suggested that the diffusion coefficient in the stratum corneum was as low as general radon-proof sheets. After a 20-min immersion in water, the simulated depth profile of radon in the skin showed that the radon activity concentration at the top surface skin layer was approximately 103 times higher than that at the viable skin layer. The information on the position of radon as a radiation source would contribute to special dose evaluation where specific target cell layers are assumed for the skin.
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Affiliation(s)
- Akihiro Sakoda
- Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama 708-0698, Japan; (N.K.); (H.T.)
- Correspondence: ; Tel.: +81-868-44-2211
| | - Tsuyoshi Ishida
- Graduate School of Health Sciences, Okayama University, 5-1 Shikata-cho 2-chome, Kita-ku, Okayama 700-8558, Japan; (T.I.); (T.K.); (K.Y.)
| | - Norie Kanzaki
- Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama 708-0698, Japan; (N.K.); (H.T.)
| | - Hiroshi Tanaka
- Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama 708-0698, Japan; (N.K.); (H.T.)
| | - Takahiro Kataoka
- Graduate School of Health Sciences, Okayama University, 5-1 Shikata-cho 2-chome, Kita-ku, Okayama 700-8558, Japan; (T.I.); (T.K.); (K.Y.)
| | - Fumihiro Mitsunobu
- Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University, 5-1 Shikata-cho 2-chome, Kita-ku, Okayama 700-8558, Japan;
| | - Kiyonori Yamaoka
- Graduate School of Health Sciences, Okayama University, 5-1 Shikata-cho 2-chome, Kita-ku, Okayama 700-8558, Japan; (T.I.); (T.K.); (K.Y.)
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