Journal of environmental radioactivity最新文献

{"title":"Indoor radon and NORM in building materials: Critical analysis of the current European regulation and road map for the next decade","authors":"Konstantin Kovler ,&nbsp;Andrey Tsapalov ,&nbsp;Robert Bobkier ,&nbsp;Rob Wiegers ,&nbsp;Wouter Schroeyers ,&nbsp;Tibor Kovács ,&nbsp;Edit Toth-Bodrogi ,&nbsp;Omar El Bounagui ,&nbsp;Arkadiusz Babczuk","doi":"10.1016/j.jenvrad.2025.107668","DOIUrl":"10.1016/j.jenvrad.2025.107668","url":null,"abstract":"<div><div>This position paper deals with the critical analysis of the existing European regulation of indoor radon and NORM in building materials. It represents an opinion of the initiative group of experts created during the Workshop of European NORM Association (ENA) held in Rome, 15–17 May 2024. The main conclusions and propositions of the experts have been also discussed at the round table during the IX Terrestrial Radioisotopes in Environment International Conference on Environmental Protection, 19–22 November 2024, Vonyarcvashegy, Hungary.</div><div>The current paper lists and discusses several missing points and challenges within the European regulatory system in the field of NORM in building materials and indoor radon, consisting of three interconnecting functional levels: Legislative, Normative, and Methodological. It also serves as a Road Map for the regulatory development in the next decade.</div><div>Our analysis identifies areas for improvement. While the normative guidance (mid-tier of the hierarchical regulatory pyramid) is robust, the legislative framework has gaps, and methodological support remains underdeveloped with several serious deficiencies. These issues significantly hinder the global implementation of GRPs. To address these gaps, new harmonized standards and guidelines are necessary. It is concluded that enhancing radon and NORM regulations can be achieved by developing and globally implementing several relevant European (international) standards and guidelines within rational ISO/IEC concepts. From a legal-philosophical perspective, these findings are intended as an invitation to dialogue, not merely a critique.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107668"},"PeriodicalIF":1.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research progress on the distribution of anthropogenic radionuclides in Northwest China","authors":"Jiahui He ,&nbsp;Yang Shao ,&nbsp;Min Luo ,&nbsp;Xiaomeng Cheng ,&nbsp;Lingling Ma","doi":"10.1016/j.jenvrad.2025.107678","DOIUrl":"10.1016/j.jenvrad.2025.107678","url":null,"abstract":"<div><div>Recent global radiological incidents have heightened attention to environmental radioactivity. Although analytical methods for anthropogenic radionuclides in environmental samples and background research are relatively well-established on a global scale, systematic research data are still lacking in the Northwest China region. This region is not only affected by global fallout caused by nuclear weapons tests in the last century, but also the regional fallout —the Lop Nor nuclear test site, China's only nuclear testing base. The various sources, complicated climate and terrain results in the unique distribution of radionuclides. Therefore, systematically summarizing the spatial distribution characteristics of artificial radionuclides in the northwest region serves as a scientific foundation for assessing the environmental risks associated with historical nuclear test legacies. It also represents a critical component in building a global nuclear safety monitoring network. Simultaneously, it provides essential data support for regional ecological environmental protection and the development of green industries. This study reviews anthropogenic radionuclide distribution in Northwest China's environment, highlighting uneven spatial coverage, incomplete nuclide inclusion, and insufficient databases. The paper proposes future directions for systematic and long-term comprehensive research, emphasizing the need to strengthen the investigation of the links between artificial radionuclides and ecological effects as well as health risks. This paper summarizes research to enhance monitoring and improve anthropogenic radionuclide background data, offering a scientific basis for policy-making and environmental protection. The review presented in this paper offers an important reference for further exploring solutions to environmental radioactivity issues in Northwest China.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107678"},"PeriodicalIF":1.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of cementitious leachate on sorption of various iodine species to sediments","authors":"Peng Lin ,&nbsp;Karah Greene ,&nbsp;Wei Xing ,&nbsp;Steven Simner ,&nbsp;Christina Logan ,&nbsp;Daniel I. Kaplan","doi":"10.1016/j.jenvrad.2025.107681","DOIUrl":"10.1016/j.jenvrad.2025.107681","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Cementitious materials are commonly used for the long-term disposal of low-level radioactive waste (LLW) in subsurface engineered disposal facilities. Iodine-129 is a key-risk driver, along with &lt;sup&gt;99&lt;/sup&gt;Tc and &lt;sup&gt;137&lt;/sup&gt;Cs, in proposed low- and high-level waste disposal facilities in the United States. The distribution coefficient (&lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;;&lt;/sub&gt; concentration ratio of I&lt;sub&gt;solid&lt;/sub&gt;/I&lt;sub&gt;liquid&lt;/sub&gt;) is one of the key parameters used for risk assessments to estimate the risk posed by radioactive waste disposal facilities. The objective of this study is to examine iodine (I) &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; values in sandy and clayey sediment environments impacted by cementitious leachate. Batch sorption experiments were conducted using subsurface sediments from Savannah River Site (SRS) for three iodine species (iodide (I&lt;sup&gt;−&lt;/sup&gt;), iodate (IO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;) and organo-iodine (org-I)). Besides the SRS groundwater (pH = 5.5), three background solutions were used to simulate the cementitious leachate in different stages of cement aging, including cementitious leachate from a freshly prepared grout (Stage I of cement aging), Ca(OH)&lt;sub&gt;2&lt;/sub&gt;-saturated solutions (Stage II, moderately aged grout leachate), and CaCO&lt;sub&gt;3&lt;/sub&gt;-saturated solutions (Stage III, aged grout leachate). Sorption of iodide (the most common iodine species) to the sandy and clayey sediments was generally undetected in most solutions, except in groundwater (0.9–5.6 L/kg). Iodate &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; values ranged from 2.1 to 14 L/kg with sandy sediment and from 3.9 to 54 L/kg with clayey sediment, with the same background solution rankings for both sediments: Stage I &lt; Stage III &lt; Stage II &lt; groundwater. Org-I demonstrated the strongest sorption to both sediments, varying from 20 to 149 L/kg to sandy sediments and from 17 to 117 L/kg on clayey sediments. Compared to groundwater conditions, the three iodine species generally demonstrated decreased sorption in the presence of cementitious leachate-impacted sediments. An important exception was org-I, which had previously been shown to comprise 45 % of the total iodine released from grout waste forms. It generally had enhanced sediment sorption in the presence of Stage II Ca(OH)&lt;sub&gt;2&lt;/sub&gt; and Stage III CaCO&lt;sub&gt;3&lt;/sub&gt; simulant. The fraction of iodine sorbed in the presence of cementitious leachate simulant with respect to the concentration sorbed under background groundwater conditions (calculated as &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt;&lt;em&gt;-CementLeach&lt;/em&gt;/&lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt;-GW) was 0.02–0.23 for iodide, 0.07–0.88 for iodate, and 0.14–5.29 for org-I. These results provided novel insight into the importance of accounting for the change in water chemistry in nuclear waste disposal systems containing cementitious engineered barriers. Neglecting to do so may result in the underestimation of the long-term risk posed by radioiodine to the environment","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107681"},"PeriodicalIF":1.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concentration ratios in fish, their natural variation, and extrapolation of missing values","authors":"Peter Saetre ,&nbsp;Olle Hjerne ,&nbsp;Ari T.K. Ikonen ,&nbsp;Lauri Parviainen ,&nbsp;Ulrik Kautsky ,&nbsp;Sari Peura","doi":"10.1016/j.jenvrad.2025.107672","DOIUrl":"10.1016/j.jenvrad.2025.107672","url":null,"abstract":"<div><div>In environmental impact assessments the biota-to-water concentration ratio (CR) is needed for calculating the transfer of radionuclides from water to aquatic organisms. Data are frequently missing, especially for rare elements, and various approaches are used for extrapolation of missing values. In this study we have analysed elemental concentrations in fish based on previously published data for brackish and freshwater. We grouped the fish according to their species and used a mixed linear model to calculate site- and ecosystem-specific CR values. These values were compared with values from different extrapolation methods (site, literature, element and ecosystem analogues). We also calculated edible versus whole body conversion factors.</div><div>The site-specific CR values frequently differed by an order of magnitude or more between the brackish and freshwater ecosystems. For most elements the value was affected by site, locality (within site) and fish type. Also the inclusion of bones affected some CR values. Literature analogues diverged more from the site data than site analogues, but these both performed better than element and ecosystem analogues. The ratio between edible and whole-body concentrations was typically similar in brackish and freshwater environments.</div><div>We conclude that a joint analysis of different aquatic ecosystems at similar sites allows for robust estimates of systematic and random variation associated with CR. We suggest that there are more possible analogues than the ones considered in the international recommendations, and that the choice of analogue should be based on the available data and the performance of the analogues in the specific assessment at hand.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107672"},"PeriodicalIF":1.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and validation of a voxel-based computational phantom of Halobatrachus didactylus (Toadfish) to study radiation protection of the marine environment","authors":"Hafssa Bendriss ,&nbsp;Jaafar EL Bakkali ,&nbsp;EL Mahjoub Chakir ,&nbsp;Abderrahim Doudouh ,&nbsp;Soufiyane Yachou","doi":"10.1016/j.jenvrad.2025.107657","DOIUrl":"10.1016/j.jenvrad.2025.107657","url":null,"abstract":"<div><div>This paper describes the creation of a voxel-based dosimetric model of a toadfish (<em>Halobatrachus didactylus</em>) from available CT images in which 29 organs are identified and segmented using 3D Slicer software. To validate the present dosimetric model Specific Absorbed Fractions (SAFs) were calculated for ten vital organs as sources and all targets, for discrete energies of electrons and photons. Then, the obtained dosimetric coefficients were compared to those calculated in similar organs in a voxel-based phantom of a trout fish (<em>Oncorhynchus mykiss)</em>. The results showed a general agreement between the comparative dosimetric data, highlighting the validity of our dosimetric model for <em>Halobatrachus didactylus</em>. We conclude that the current dosimetric fish model can be applied in future research to evaluate dosimetry calculations related to radiation exposure in regions surrounding the Fukushima accident site.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107657"},"PeriodicalIF":1.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the effect of surface cracks in overburden on radon exhalation in uranium tailings ponds under freeze-thaw cycles","authors":"Kai Liu ,&nbsp;Yong Liu ,&nbsp;Hong Wang ,&nbsp;Changshou Hong ,&nbsp;Yifan Chen ,&nbsp;Weiwei Yin ,&nbsp;Chenxiao Chang","doi":"10.1016/j.jenvrad.2025.107671","DOIUrl":"10.1016/j.jenvrad.2025.107671","url":null,"abstract":"<div><div>Freeze-thaw (F-T) climate causes cracking in the soil cover of uranium tailing ponds, and the exhalation of the carcinogenic gas radon needs to be monitored under the phenomenon. In laboratory experiment, cracking tests under 5 F-T cycles were carried out on 3 soil uranium tailing pond models, including Gansu loess (GS-L), Hengyang laterite (HY-L), and Hebei loess (HB-L). Each cycle consisted of −15 °C, 12 h of freezing and 15 °C, 12 h of thawing. The area, length, mean width and fractal dimension of the cracks on the soil surface were quantified using digital imaging techniques, the correlation of parameters with the radon exhalation was compared. Finally, the qualitative explanation was provided from the perspectives of visual and scanning electron microscopy (SEM). The results showed that: Fine, short and irregular cracks developed to penetrating wide cracks after the 3rd cycle. The radon barrier capacity of the soil was negatively correlated with the number of F-T cycles. After 5th cycles, the radon exhalation rates of GS-L, HY-L, and HB-L were 0.675 <span><math><mrow><mi>B</mi><mi>q</mi><mo>/</mo><mrow><mo>(</mo><mrow><msup><mi>m</mi><mn>2</mn></msup><mo>·</mo><mi>s</mi></mrow><mo>)</mo></mrow></mrow></math></span>, 0.555 <span><math><mrow><mi>B</mi><mi>q</mi><mo>/</mo><mrow><mo>(</mo><mrow><msup><mi>m</mi><mn>2</mn></msup><mo>·</mo><mi>s</mi></mrow><mo>)</mo></mrow></mrow></math></span>, and 0.462 <span><math><mrow><mi>B</mi><mi>q</mi><mo>/</mo><mrow><mo>(</mo><mrow><msup><mi>m</mi><mn>2</mn></msup><mo>·</mo><mi>s</mi></mrow><mo>)</mo></mrow></mrow></math></span>, which increased by 63.8 %, 43.1 %, and 39.6 %, respectively. The mean width of cracks showed the highest correlation with radon exhalation rate: HY-L (0.91), GS-L (0.89), and HB-L (0.87). SEM results showed fewer soil internal pores mean harder radon migration. The findings are relevant to the monitoring of radioactive gas in uranium tailing ponds.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107671"},"PeriodicalIF":1.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radium isotopes as tracers of lacustrine groundwater discharge: Review and prospects","authors":"Weigang Su,&nbsp;Xiaolong Yuan,&nbsp;Xiying Zhang","doi":"10.1016/j.jenvrad.2025.107680","DOIUrl":"10.1016/j.jenvrad.2025.107680","url":null,"abstract":"<div><div>Lacustrine groundwater discharge (LGD) is a crucial component of lake hydrological budgets and serves as a significant source such as nutrients and pollutants. Naturally occurring radioactive radium isotopes (²²³Ra, ²²⁴Ra, ²²⁶Ra, ²²⁸Ra) have emerged as valuable tracers for studying lacustrine groundwater discharge due to their distinctive geochemical properties. While radium isotopes were primarily utilized in studies of submarine groundwater discharge in the past, their \"salt effect\" characteristics have increasingly established them as essential tools for identifying and quantifying LGD. This review focuses on the application and research advancements of radium isotopes in tracing LGD, encompassing concepts and methodologies related to lacustrine groundwater discharge, the geochemical characteristics of radium isotopes, the development of radium isotope tracing techniques for LGD, and strategies for source identification and quantification of radium in the groundwater discharge process. Furthermore, this review addresses several limitations and challenges encountered in the application of radium isotope tracing techniques for LGD research and outlines future research directions that could enhance the quantitative study of radium isotopes.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107680"},"PeriodicalIF":1.9,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Geiger–Müller network for anomaly detection and tracking for accident preparedness at KAERI","authors":"Jaehyeon Seo ,&nbsp;Jong-Myoung Lim ,&nbsp;Suyeon Hyeon ,&nbsp;Min Sun Lee","doi":"10.1016/j.jenvrad.2025.107676","DOIUrl":"10.1016/j.jenvrad.2025.107676","url":null,"abstract":"<div><div>Monitoring environmental radiation around nuclear facilities is critical for safety and regulatory compliance. Traditional methods, such as environmental radiation monitoring using high-pressure ion chambers and thermoluminescent dosimeters, have limitations with regard to cost, complexity, and response time. To address these issues, we developed a compact Geiger–Müller (GM) counter-based detector network for real-time radiation monitoring at the Korea Atomic Energy Research Institute (KAERI). The developed GM detector module is operated using a battery and a solar panel to ensure maintenance-free operation and is equipped with LTE wireless communication. The Daejeon KAERI site spans approximately 1.42 km², where a total of 50 GM modules were installed, forming a high-resolution radiation monitoring network. In addition, convolutional neural network-based radiation anomaly detection and source-tracking models were developed to enhance the monitoring capabilities. The anomaly-detection model achieved an accuracy of 0.9999 and an area under the receiver operating characteristic curve of 0.9999, effectively distinguishing between normal and anomalous radiation. The source-tracking model predicted source locations with an average error of 3.44 m for the test set. In field experiments using a low-intensity ¹³⁷Cs source, the average error was 54.73 m. The proposed cost-effective, high-resolution radiation mapping solution can be easily deployed and maintained, ensuring comprehensive coverage and timely detection of radiation anomalies.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107676"},"PeriodicalIF":1.9,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uptake of technetium and iodine (I−, IO3− and organo-I) by pecan biochar","authors":"Peng Lin ,&nbsp;Brennan Ferguson ,&nbsp;Karah M. Greene ,&nbsp;Wei Xing ,&nbsp;Chen Xu ,&nbsp;Christopher E. Bagwell ,&nbsp;Donald W. Watts ,&nbsp;Daniel I. Kaplan","doi":"10.1016/j.jenvrad.2025.107674","DOIUrl":"10.1016/j.jenvrad.2025.107674","url":null,"abstract":"<div><div>Remediation of land and groundwater that are contaminated with high-risk driving anionic-radionuclides, such as iodine-129 (I-129) and technetium-99 (Tc-99), remains an intractable problem. The objective of this study was to evaluate biochar materials as a low-cost and effective sorbent for Tc-99 and three iodine species, iodide/iodate/organo-iodine (org-I). Sorption studies were conducted with biochar derived from pecan shells (<em>Carya illinoinensis</em>), that underwent two pyrolysis temperatures (500 °C and 700 °C) and two types of acid-activation (H₃PO₄ and HCl). Acid-activated biochar had much higher sorption capacities (in terms of distribution coefficient, <em>K</em>_<em>d</em>, the concentration ratio of solid:liquid) for Tc-99 and different iodine species, than non-acid-activated biochar. The H₃PO₄-activated biochar (500 °C) was the most effective sorbent with Tc-99 <em>K</em>_<em>d</em> of 49,390 ± 14,268 mL/g, iodide <em>K</em>_<em>d</em> of 2433 ± 312 mL/g, iodate <em>K</em>_<em>d</em> of 410 ± 168 mL/g, and org-I <em>K</em>_<em>d</em> of 857 ± 181 mL/g. The HCl-activated biochar (700 °C) was also effective at sequestering Tc-99 (<em>K</em>_<em>d</em> of 7864 ± 5,585 mL/g) and iodide (<em>K</em>_<em>d</em> of 2481 ± 237 mL/g) but not for iodate/org-I. Solid-state ¹³C-nuclear magnetic resonance (NMR) analysis suggested the strong sorption capacity related to the formation of abundant alkene, aromatic and heteroaromatic functional groups, which was also supported by the Fourier-transform infrared spectroscopy (FTIR) analysis. Additionally, the FTIR suggested the possible electrophilic substitution of C-H by iodine to form C-I bond. Surface area measurements and SEM images indicated the H₃PO₄-activated biochar (500 °C) had especially high surfaces areas. Functionalized biochar may provide a cost effective and efficient sorbent for sequestering I-129 and Tc-99 from the biosphere, thereby reducing human risk.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107674"},"PeriodicalIF":1.9,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparative evaluation of 222Rn sealing materials for 226Ra analysis by gamma spectrometry","authors":"Han Chang Seo,&nbsp;Hyeon-Woo Lee,&nbsp;Kyeong Ho Kim,&nbsp;Jeongsoo Kang,&nbsp;Jung-Seok Chae","doi":"10.1016/j.jenvrad.2025.107673","DOIUrl":"10.1016/j.jenvrad.2025.107673","url":null,"abstract":"<div><div>The accuracy of indirect measurements of ²²⁶Ra using gamma spectrometry critically depends on sealing techniques that prevent the escape of ²²²Rn (radon) generated within the sample. This study introduces a novel sealing method designed to overcome the limitations of conventional Rn sealing techniques. The Rn sealing performance of five sealing materials—silicone sealant, modified silicone sealant, butyl sealant, polyurethane sealant, and epoxy adhesive—was evaluated by sealing sample containers filled with Rn-containing water samples using each of the five materials, measuring Rn over time, and comparing experimentally estimated half-life of Rn for each sealed container with its physical half-life. Among the five sealing materials evaluated, the experimentally estimated half-life of Rn in samples sealed with modified silicone sealant, butyl sealant, polyurethane sealant, and epoxy adhesive, excluding silicone sealant, closely matched the physical half-life of Rn, demonstrating their reliable sealing performance. To verify the validity of the sealing method, the activity concentration of ²²⁶Ra was estimated in IAEA-434 phosphogypsum, a certified reference material, sealed with five different sealing materials. The results showed that for the four sealing materials, excluding silicone sealant, the measured values were statistically consistent with the certified value of IAEA-434, confirming the validity of the sealing method using these materials. The proposed sealing method enables accurate analytical results without requiring the complete filling of the measurement container, allows for visual inspection of the sample's filling state, and facilitates sample reuse for further analyses. These advantages make it a practical approach for the routine analysis of NORM and environmental samples.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"285 ","pages":"Article 107673"},"PeriodicalIF":1.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}