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Hu X, Sun Q, Shi Q, Wang N, Geng J, Xue S. Radon exhalation characteristics after pyrolysis of long flame coal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:167228. [PMID: 37734598 DOI: 10.1016/j.scitotenv.2023.167228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/26/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Coal pyrolysis is a important method for classifying and utilizing coal resources and contributes to enhanced comprehensive resource utilization. However, In high-temperature areas such as coal pyrolysis, there is an abnormal phenomenon release of radioactive gas radon, understanding the relationship between temperature and radon exhalation characteristics, as well as the underlying mechanisms, holds great importance for assessing radon pollution in mining areas. After coal undergoes pyrolysis under high temperature conditions, its material composition, pore structure, water content, and other properties have changed. The pyrolysis products in different atmosphere environments have differences, and the characteristics of radon emission are also different. To address this, the present study conducted coal pyrolysis experiments in both aerobic and anaerobic environments, using long flame coal sourced from Yulin, China. The radon release concentration of the pyrolysis products was measured. The research findings indicate that during pyrolysis at elevated temperatures, the ratio of coal mass loss is constantly increasing. High temperatures promote the development of pores and fissures, and significant changes in coal properties at temperature thresholds (300 °C and 500 °C). The specific surface area, pore volume, and fracture ratio all display substantial increases, and the amplitude of change is greater under aerobic conditions. The fractal dimension of total pores and macropores shows continuous growth, while the specific surface area, pore volume, and fracture ratio exhibit a strong negative correlation with the radon emission rate of pyrolysis products. The expansion and penetration of pores and cracks, along with the release of a substantial amount of pyrolysis gas, accelerate the transformation, migration, and exhalation of radon, resulting in a negative correlation between the heat treatment temperature and the radon release rate of pyrolysis products. Under aerobic conditions, the radon release rate of pyrolysis products decreases more significantly.
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Affiliation(s)
- Xin Hu
- 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.
| | - Qingmin Shi
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Nianqin Wang
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Jishi Geng
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Shengze Xue
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
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Shahrokhi A, kovács T. Characterization of environmental radiological parameters on dose coefficient - Realistic dosimetry compared with epidemiological dosimetry models. Heliyon 2023; 9:e19813. [PMID: 37809865 PMCID: PMC10559164 DOI: 10.1016/j.heliyon.2023.e19813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 10/10/2023] Open
Abstract
Radiation exposure due to all-natural sources amounts to about 2.4 mSv per year. However, this amount might be changed to over 3 mSv y-1 according to the recently introduced ICRP radon dose coefficient factor. Previously, the radon contribution to the total dose from natural sources was about 1.2 mSv y-1. However, after the latest introduced dose conversion factor by ICRP, this value could technically be increased to around 2 mSv y-1. This paper attempts to address the following questions: (i) whether reducing radon concentration to the recommended level could address concerns about radiation exposure in underground workplaces, and (ii) the effects of the difference between the epidemiological dosimetry models and realistic dose estimation. The actual dose conversion factor (DCF) was calculated using measured annual average unattached and equilibrium factors, ranging from 16 ± 9 to 25 ± 10 mSv·WLM-1. Then, the estimated inhalation dose, both from self-calculated DCF and the value reported by ICRP-137, was compared: 5.6 ± 0.7-7.6 ± 0.9 mSv y-1 and 3.3 ± 0.4-3.6 ± 0.5 mSv y-1, respectively. It can be observed that exposure to a radon concentration lower than the recommended level does not guarantee a lower dose than the recommended value. The estimated dose was at least two times greater than the dose using pre-estimated values from epidemiological dosimetry models, specifically in this case study. Further experiments in different underground working environments, excluding caves, are needed for more precise observations. It might also be time to update the data regarding the dose contribution from natural radiation sources, as the radon contribution increased according to ICRP.
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Affiliation(s)
- Amin Shahrokhi
- Department of Radiochemistry and Radioecology, Research Centre for Biochemical, Environmental and Chemical Engineering, University of Pannonia, 8200, Veszprém, Hungary
| | - Tibor kovács
- Department of Radiochemistry and Radioecology, Research Centre for Biochemical, Environmental and Chemical Engineering, University of Pannonia, 8200, Veszprém, Hungary
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Preparation and characterization of a high-efficiency radon adsorbing material based on activated carbon modified by water immersion and freeze–thaw. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08345-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Use of microwave closed-loop desorption method to evaluate the desorption characteristics of activated carbon absorbed radon. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08243-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Quantification of doses and health risks to organs and tissues corresponding to different age groups due to radon in water. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-08050-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Shahrokhi A, Adelikhah M, Imani M, Kovács T. A brief radiological survey and associated occupational exposure to radiation in an open pit slate mine in Kashan, Iran. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07778-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractA comprehensive radiological survey was carried out in an open-cut slate stone quarry. The activity of 226Ra, 228Ra and 40 K in the ore samples were measured as 38 ± 5, 41 ± 6 and 869 ± 52 Bq kg1, respectively. Outdoor radon and indoor radon concentrations were measured from 37 ± 7 to 193 ± 11 Bq m−3 (77 ± 8 Bq m−3), and 49 ± 6 to 253 ± 23 Bq m−3 (131 ± 13 Bq m−3), respectively. The average indoor and outdoor gamma dose were measured as 116 and 84 nSv h− 1, respectively. The annual effective doses were estimated between 1.0 ± 0.1 and 3.3 ± 0.3 mSv year−1. The annual lung cancer risks were calculated in the range of 3.3 × 10−2 to 13.12 × 10−2 % (7.72 × 10−2%).
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Adelikhah M, Shahrokhi A, Chalupnik S, Tóth-Bodrogi E, Kovács T. High level of natural ionizing radiation at a thermal bath in Dehloran, Iran. Heliyon 2020; 6:e04297. [PMID: 32642584 PMCID: PMC7334375 DOI: 10.1016/j.heliyon.2020.e04297] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/14/2020] [Accepted: 06/22/2020] [Indexed: 11/25/2022] Open
Abstract
It has been proven that more than half of the exposure to natural background radiation originates from radon isotopes and their decay products. The inhalation of radon and its decay products causes the irradiation of respiratory tracts, thus increasing the risk of lung cancer. In this study, the concentrations of radon and thoron in thermal baths at a spa in Dehloran (Iran) were investigated. The concentrations of dissolved 226Ra in samples of water from thermal baths were also measured. Additionally, the activity concentrations of abundant naturally occurring radionuclides in farmland soils irrigated with water from hot springs was measured and compared with other soil samples irrigated with water from other sources to estimate possible radioecological effects of natural radiation staff, patients and tourists at the spa are exposed to. In addition, the search for a link between the concentration of naturally occurring radionuclides in soil and the use of water from hot springs for irrigation was one of the main goals of the study. The activity concentrations of three major naturally occurring radionuclides in soil samples were measured; the ranges for 40K, 226Ra and 228Ra were 101 ± 8 to 240 ± 12, 276 ± 7 to 322 ± 12 and 20 ± 7 to 80 ± 10 Bq.kg−1, respectively. Higher activity concentrations of 226Ra and 228Ra were recorded in soil samples irrigated with hot spring water. The water from the same spring was used in all thermal baths so concentrations of dissolved 226Ra in water samples from different thermal baths were approximated to also be 0.42 ± 0.20 Bq.l−1. The indoor radon concentrations in the private thermal baths over a period of 45 days (including both occupied and vacant time) were measured to be between 1880 ± 410 and 2450 ± 530 Bq.m−3 and the radon concentrations in the spa galleries were measured to be between 790 ± 135 and 1050 ± 120 Bq.m−3, however, thoron concentrations were below the detection limit. The ventilation and centralized heating systems at the spa under investigation are inefficient so the radon concentrations in the therapy rooms and baths are high. The maximum radiation doses originating from the inhalation of radon for tourists and the staff were estimated to be 0.13 and 5.5 mSv.yr−1, respectively, which is slightly over the national limit in Iran (5 mSv.yr−1). The exposure duration was estimated 15 and 1468 h per year for visitors and workers, respectively.
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Affiliation(s)
- Mohammademad Adelikhah
- Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, Veszprém, Hungary
| | - Amin Shahrokhi
- Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, Veszprém, Hungary
| | - Stanislaw Chalupnik
- Silesian Centre for Environmental Radioactivity, Central Mining Institute, Plac Gwarków, 40-166, Katowice, Poland
| | - Edit Tóth-Bodrogi
- Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, Veszprém, Hungary
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, Veszprém, Hungary
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Müllerová M, Holý K, Smetanová I, Kureková P. VARIATION OF RADON ACTIVITY CONCENTRATION IN SELECTED KINDERGARTENS IN SLOVAKIA. RADIATION PROTECTION DOSIMETRY 2019; 186:401-405. [PMID: 31711196 DOI: 10.1093/rpd/ncz240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Radon measurements were carried out in four kindergartens in Slovakia. RSKS detectors (Radosys Ltd., Hungary) and RamaRn (SUJCHBO, Czech Republic) were used for integral measurement in indoor air. AlphaGUARD (Saphymo, Germany) and TERA system (Tesla, Czech Republic) were used for continual measurement in indoor air. An annual variation with a maximum during the summer holidays was observed. Daily variation strongly depended on the ventilation of rooms. The average radon activity concentration per unit of time calculated from integral measurements was higher than that calculated for working time only.
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Affiliation(s)
- Monika Müllerová
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F-1, 841 04 Bratislava, Slovak Republic
| | - Karol Holý
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F-1, 841 04 Bratislava, Slovak Republic
| | - Iveta Smetanová
- Earth Science Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 840 05 Bratislava, Slovak Republic
| | - Patrícia Kureková
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F-1, 841 04 Bratislava, Slovak Republic
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