Journal of environmental radioactivity最新文献

{"title":"Strengthening potential of recent peat dating","authors":"Anna Cwanek ,&nbsp;Marco A. Aquino-Lopez ,&nbsp;Piotr Kołaczek ,&nbsp;Mariusz Lamentowicz ,&nbsp;Barbara Fiałkiewicz-Kozieł ,&nbsp;Mariusz Gałka ,&nbsp;Michał Słowiński ,&nbsp;Dominika Łuców ,&nbsp;Katarzyna Marcisz ,&nbsp;Milena Obremska ,&nbsp;Sambor Czerwiński ,&nbsp;Edyta Łokas","doi":"10.1016/j.jenvrad.2024.107594","DOIUrl":"10.1016/j.jenvrad.2024.107594","url":null,"abstract":"<div><div>This study concerned high-resolution age reconstructions of modern organic deposits collected from peatlands distributed in Central Europe. The main focus was on ²¹⁰Pb radioisotope as a fundamental geochronometer along with ¹⁴C and ^239+240Pu radioisotopes used for dating verification. In addition to simple classical models such as CF/CS or CF, the new approach formulated upon the Plum method was implemented. Examined peat profiles with usually poorly defined equilibrium depth revealed a high complexity manifested by vertical variability of both ²¹⁰Pb activity concentration and bulk density. The performance of dating models required prior slight corrections, which led to reliable and accurate chronologies for most of the profiles, representing various peatland types (bogs, poor fens and fens). Moreover, the age series of different ²¹⁰Pb models were highly consistent for a given core. The ²¹⁰Pb inventory and flux assessment exhibited maxima (SE, 1σ) of 8450 (90) Bq m⁻² and 280 (20) Bq m⁻² y⁻¹, respectively, reflecting an elevated level of ²²²Rn exhalation in the Sudetes region. No statistically significant regularities were found in the geographical distribution of ²¹⁰Pb fluxes or accumulation rates.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107594"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807045","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":"Characterizing major and trace element concentrations, and radioactivity in bulk glass samples from the trinity atomic test","authors":"Nelson Eby ,&nbsp;George Chabot ,&nbsp;Robert Hermes","doi":"10.1016/j.jenvrad.2024.107591","DOIUrl":"10.1016/j.jenvrad.2024.107591","url":null,"abstract":"<div><div>Glass fragments (16 green glasses and 2 red glasses) were handpicked from crushed Trinitite. X-ray diffraction studies revealed that these samples were essentially pure glass with the exception of minor amounts (less than 4 wt%) of quartz (which acts as a diluent) in some samples. The concentrations of 45 elements in the Trinity glasses were determined using Instrumental Neutron Activation Analysis. Plutonium-239 concentrations were determined by measuring the activity of fission products produced during thermal neutron irradiation of the glasses. The activity of various radionuclides was determined by gamma ray spectroscopy. Elemental concentrations were also determined for 12 arkosic sand samples from the Trinity site. The Trinity glasses are essentially a mixture of arkosic sand, radionuclides and elements from the atomic device, and elements associated with the structures in the immediate vicinity of the test site. Comparison of glass chemistry to the arkosic sand chemistry allows an assessment to be made of the addition and removal of various elements during glass formation.</div><div>Ba-133 and Cs-137 are linearly related to the Pu-239 + U-235_device content of the glasses. Barium (Baratrol) was used in the device and Ba-133 activity has a positive y-intercept, which suggests that some of the Ba-133 activity may be due to activation of Ba in the arkosic sands. For Cs-137, the y-intercept is negative which suggests a depletion of Cs-137 in the glasses. The present-day Am-241 activity shows a linear relationship with Pu-239 activity (r² = 0.99). Am-241 is derived via beta decay of Pu-241, and the Pu-241/Pu-239 activity ratio can be used to distinguish different Pu sources. For the Trinity glasses, this ratio is 0.70 ± 0.16.</div><div>Relative to the arkosic sand elemental concentrations, the glasses are depleted in As, Br, Cs, Sb, Se, and Zn presumably because of their relatively high volatility. The depletion of several other elements (Co, Ir, Mg, Ni, V, W) may be due to their removal by metallic droplets during glass formation. Relative enrichment of U, Mo, Ti, and Ba is due to addition of these elements from the atomic device and associated structures.</div><div>The residual activity of Eu-152 is used to determine the distance of individual glass samples from ground zero. Most of the samples fall between 40 and 50 m (near the edge of the glass free crater formed during the atomic explosion). Similar results were obtained for a different batch of samples using residual Co-60 activity. The inference is that the material that comprises the bulk of the glass originated close to ground zero and was distributed across the site as an ejection blanket. Material from the atomic bomb was added during the formation of this ejection blanket.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107591"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142785828","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":"Baseline tritium measurements in Thailand's water bodies: Supporting sustainable nuclear energy development","authors":"Wanwisa Sudprasert ,&nbsp;Kanokwan Khamanek ,&nbsp;Soontree Khuntong ,&nbsp;Jamnong Tanyasit ,&nbsp;Kiadtisak Saenboonruang ,&nbsp;Donruedee Toyen ,&nbsp;Monthon Yongprawat ,&nbsp;Chakrit Saengkorakot ,&nbsp;Chittranuch Chantarot ,&nbsp;Archara Phattanasub ,&nbsp;Piyawan Krisanangkura ,&nbsp;Anawat Rittirong ,&nbsp;Ryuta Hazama","doi":"10.1016/j.jenvrad.2024.107604","DOIUrl":"10.1016/j.jenvrad.2024.107604","url":null,"abstract":"<div><div>Tritium, a radioactive isotope produced naturally through cosmic radiation interactions and anthropogenically through nuclear weapons testing, poses potential environmental risks, particularly within the water cycle. This study measured tritium concentrations in surface water across Thailand to establish a baseline dataset for monitoring potential contamination from nuclear activities and accidents. Surface water samples were collected from 14 large reservoirs during the wet season in October 2023 and the dry season in February 2024, providing a total of 28 samples. Tritium concentrations were analyzed using electrolytic enrichment and liquid scintillation counting techniques. The results, presented with combined uncertainty, revealed tritium levels ranging from 1.21 ± 0.19 to 2.74 ± 0.23 TU (0.14 ± 0.02 to 0.32 ± 0.03 Bq·L⁻¹), with an average of 1.94 ± 0.01 TU (0.23 ± 0.00 Bq·L⁻¹). The highest concentrations were observed in the north (2.26 ± 0.02 TU), followed by the northeast (2.13 ± 0.04 TU), central (1.91 ± 0.05 TU), east (1.72 ± 0.03 TU), and south (1.55 ± 0.04 TU). All measured tritium levels were below the natural background threshold of 10 TU and complied with the surface water quality standards set by the Thailand's Pollution Control Department. Tritium concentrations were positively correlated with latitude, distance from the coast, and elevation, while showing an inverse relationship with pH. No significant seasonal variations or correlations were observed with ion concentrations, water temperature, electrical conductivity, salinity, dissolved oxygen, or total dissolved solids. These baseline measurements are essential for supporting sustainable nuclear energy development and ensuring effective monitoring of environmental radioactivity. The dataset provides a critical reference for Thailand's regulatory agencies, such as the Office of Atoms for Peace, to safeguard public and environmental safety under both normal operations and potential radiological emergency scenarios.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107604"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872181","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":"Spatial unfolding of an extended La-140 source within a 0.5 km-wide exclusion zone using Compton gamma imaging measurements","authors":"N.J. Murtha ,&nbsp;P.R.B. Saull ,&nbsp;L.E. Sinclair ,&nbsp;A.M.L. MacLeod ,&nbsp;A. McCann","doi":"10.1016/j.jenvrad.2024.107605","DOIUrl":"10.1016/j.jenvrad.2024.107605","url":null,"abstract":"<div><div>Results from applying an advanced spatial-unfolding technique to outdoor-trial data acquired with a <em>Silicon photomultiplier-based Compton Telescope for Safety and Security</em> (SCoTSS) gamma imager during perimeter survey of a distributed La-140 source lying within a 500 m x 500 m exclusion zone are presented. A synthetic-data version of the experiment was also modelled using Monte Carlo simulations and reconstructed. For both experimental and synthetic data the method faithfully reproduces the shape of the activity distribution, and for synthetic data the total activity is reproduced as well. However, for the experimental data the method underestimates the total activity by a factor of six. This can be accounted for by environmental snow and soil conditions not included in the detector response functions. This application of the Compton gamma imager survey-data inversion method demonstrates its applicability under austere conditions wherein extreme weather and transportation constraints severely impacted the quality of the data collected. The trial shows that the method has widespread applicability in the radiological and nuclear safety and security field, particularly for scenarios in which a threat material or contaminated area lies within a no-entry or no-fly zone.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107605"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142949984","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":"Long-term studies on the temporal change of radiocesium in wild rodents and insectivores in Nihonmatsu City, Fukushima Prefecture, Japan","authors":"Minato Okumura ,&nbsp;Shunsuke Ikeuchi ,&nbsp;Yomogi Sato ,&nbsp;Nguyen Khanh Thuan ,&nbsp;Haruka Yanagawa ,&nbsp;Bui Thi Hien ,&nbsp;Takeshi Niwa ,&nbsp;Hideki Hayashidani","doi":"10.1016/j.jenvrad.2024.107582","DOIUrl":"10.1016/j.jenvrad.2024.107582","url":null,"abstract":"<div><div>The radiocesium (¹³⁴Cs and ¹³⁷Cs) released by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 has a relatively long physical half-life and may remain in the natural environment for a long period of time and continue to be transferred to wildlife. In this study, we conducted a fixed-point investigation of radiocesium activity concentrations in stomach contents and skeletal muscles samples of wild rodents (<em>Apodemus speciosus</em>, <em>Apodemus argenteus</em> and <em>Microtus montebelli</em>) and insectivores (<em>Urotrichus talpoides</em>) from 2012 to 2021. Two sampling sites in Mt. Kuchibutoyama and Mt. Hayama were selected in forested areas in Fukushima Prefecture. In Mt. Kuchibutoyama, a decreasing trend in ¹³⁷Cs activity concentrations was observed for stomach contents of wild rodents and insectivores as a whole and for skeletal muscle of <em>A. speciosus</em> and <em>A. argenteus</em>. The effective half-life (T_ef) of ¹³⁷Cs activity concentration was estimated to be 7.6 years in the stomach contents, and 5.4 years and 7.4 years in skeletal muscle of <em>A. speciosus</em> and <em>A. argenteus</em>, respectively, with corresponding ecological half-life (T_ec) of 10 years in the stomach contents, and 6.6 years (<em>A. speciosus</em>) and 9.8 years (<em>A. argenteus</em>) in the skeletal muscle. In Mt. Hayama, there was a slight upward trend in the ¹³⁷Cs activity concentration in the stomach contents of wild rodents and insectivores, and no significant T_ef could be obtained. Statistically significant T_ef and T_ec could not also be estimated for ¹³⁷Cs radioactivity levels in skeletal muscle of <em>A. speciosus</em> and <em>A. argenteus</em>. These results suggest that ¹³⁷Cs concentration in insects and plants eaten by wild rodents and insectivores in Mt. Hayama has remained at a certain level for a long time. In November 2021, ¹³⁷Cs concentrations above 1.0 kBq/kg were still detected in skeletal muscle of <em>A. argenteus</em> captured in Mt. Kuchibutoyama and <em>A. speciosus</em> and <em>A. argenteus</em> captured in Mt. Hayama. It is expected that ¹³⁷Cs concentration levels in the stomach contents and skeletal muscles of these wild rodents and insectivore will remain for a long time to come, especially at Mt. Hayama. Furthermore, we also collected soil and plant samples when sampling wild rodents and insectivores in this study. It is important as a future task to study temporal changes in radiocesium activity concentrations in the habitat of wild small mammals and to examine the relationship between these changes and temporal changes in radiocesium activity concentrations in wild small mammals.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107582"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142791936","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":"Exploratory study of erosion in cultivated organic soils using cesium-137 measurements","authors":"Alexis Gloutney ,&nbsp;Claude Bernard ,&nbsp;Jacynthe Dessureault-Rompré","doi":"10.1016/j.jenvrad.2024.107574","DOIUrl":"10.1016/j.jenvrad.2024.107574","url":null,"abstract":"<div><div>Concerns about the sustainability of cultivated organic soils in Montérégie (Quebec, Canada), which can also be identified as histosols, led to this exploratory study aimed at quantifying erosion in these soils by using cesium-137 (¹³⁷Cs) measurements. Soil samples were taken from organic soils in twenty-two fields, and their ¹³⁷Cs contents were measured by gamma spectrometry. The estimated mean annual erosion rates (±SD), adjusted with cropping history, ranged from 0.4 ± 6.3 to 14.6 ± 10.7 t/ha. The results obtained are lower than expected, based on information provided by the agricultural producers from whose farms the samples were taken, as well as two studies conducted in the same study area that highlight the importance of cultivated organic soil height loss due to wind erosion. Recommendations are formulated to obtain more precise erosion rates in future research. This study also points out aspects that deserve to be investigated to adapt existing conversion models for erosion assessment using ¹³⁷Cs measurements in cultivated organic soils.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107574"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872183","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":"90Sr and 137Cs distribution in Chornobyl forests: 30 years after the nuclear accident","authors":"D. Holiaka ,&nbsp;S. Levchuk ,&nbsp;V. Kashparov ,&nbsp;V. Yoschenko ,&nbsp;P. Hurtevent ,&nbsp;F. Coppin ,&nbsp;J.C. Beasley","doi":"10.1016/j.jenvrad.2025.107616","DOIUrl":"10.1016/j.jenvrad.2025.107616","url":null,"abstract":"<div><div>The primary aim of this study was to quantify patterns in the distribution of ⁹⁰Sr and ¹³⁷Cs activity in pine (<em>Pinus sylvestris</em> L.: 18 sites) and birch (<em>Betula pendula</em> Roth.: 2 sites) forests within the Chornobyl exclusion zone, 30 years after the Chornobyl nuclear power plant (NPP) accident (1986). To achieve this, radionuclide activity concentrations were measured in the mineral and organic soil horizons, the green forest floor (grasses, mosses, and lichens), and trunk wood in forest plots dominated by either pine or birch trees.Our results showed that the geometric mean of the ⁹⁰Sr aggregated transfer factors from mineral soil to the trunk wood of pine trees (T_ag) for Scots pines was 24 x 10⁻³ m² kg⁻¹, which is an order of magnitude higher than the IAEA Handbook (2010)reference value (1.7 x 10⁻³ m² kg⁻¹), which were based on studies conducted after the Kyshtym accident (Ural region, Russia) and in the first years following the Chornobyl accident (Ukraine and Belarus). The observations suggest that the above-ground biomass (soil organic layers, green forest floor, and trees) may contribute more to the ⁹⁰Sr inventory than the mineral soil at the stand level. In contrast, the ¹³⁷Cs T_ag values for pine and birch stands were consistent with those reported in the literature (ranging from 0.1 to 10 and 0.5-1.1 x 10⁻³ m² kg⁻¹, respectively). Both results align with the known bioavailability of radionuclides from previous studies: low for ¹³⁷Cs, leading to limited soil depth migration (less than 30 cm in the mineral horizon), and higher for ⁹⁰Sr, resulting in greater soil migration (up to 1 m in the mineral horizon). This study highlighted significant correlations between the radionuclides' activity concentrations in the litter layers and their content in the trunk wood of pine trees.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107616"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142964693","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":"Improved soil-to-plant transfer factors for 99Tc and 79Se in natural and agricultural ecosystems","authors":"Eleni Siasou,&nbsp;Neil Willey","doi":"10.1016/j.jenvrad.2025.107622","DOIUrl":"10.1016/j.jenvrad.2025.107622","url":null,"abstract":"<div><div>Geological Disposal Facilities (GDFs) are the preferred option for the disposal of high- and medium-level nuclear waste but environmental assessments for GDFs are complex. Models of transfer into the biosphere for radioisotopes that occur in nuclear waste rely on estimated Transfer Factors (TFs) that often have high levels of uncertainty and only exist for a few species. Here, using two key radioisotopes found in nuclear waste, we show that taxonomic analyses and phylogenetically based trait prediction (PTP) can be used to both reduce uncertainty in current estimates of soil-to-plant TF and to predict them for the many species with no measurements. We grew 61 species of plants selected to provide a phylogenetically informed sample, measured their uptake of ⁹⁹Tc and ⁷⁵Se, and reconstructed their possible evolutionary relationships using gene sequence information. The uptake of Tc and Se isotopes by plants was correlated, and for Tc was more similar within plant groups than between them and included significant taxonomic and phylogenetic influences. We use these findings to suggest improved soil-to-plant Transfer Factors (TFs) for⁹⁹Tc and ⁷⁹Se. We suggest that the approaches we used might be useful for a range of radionuclides, in both improving current estimates of TF and for predicting TFs to plants and, perhaps, to other biota. Such improvements might be useful not only for environmental assessments of nuclear waste disposal but also the environmental regulation of a nuclear industry being expanded in several nations to help meet targets for reducing global CO₂ emissions.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107622"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143074704","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":"Modelling soil – Vegetation – Atmospheric interactions of radon products in a Belgian Scots pine forest site","authors":"Jordi Vives i Batlle","doi":"10.1016/j.jenvrad.2024.107607","DOIUrl":"10.1016/j.jenvrad.2024.107607","url":null,"abstract":"<div><div>A soil-vegetation-atmospheric transfer (SVAT) model for radon and its progeny is presented to improve process-level understanding of the role of forests in taking-up radionuclides from soil radon outgassing. A dynamic system of differential equations couples soil, tree (Scots pine) and atmospheric processes, treating the trees as sources, sinks and conduits between the atmosphere and the soil. The model's compartments include a dual-layer soil column undergoing hydrological and solute transport, the tree system (comprising roots, wood, litter, and foliage) and the atmosphere, with physical processes governing the transfers of water and radon products between these compartments. A dose post-processor calculates dose rates to the trees from internal, external, and surface radiation exposures. The model parameterisation is based on measurement data from the Grote Nete Valley in the Belgian Campine region.</div><div>The model results suggest that the tree intake of radon progeny is principally from the atmosphere, whereas radium is mainly taken-up from soil by the root uptake process, leading to an additional fraction of ingrown radon progeny in the tree by this route. It is also suggested that atmospheric uptake of radon is an essential mechanism when evaluating the tree uptake of ²¹⁴Po, ²¹⁴Pb and ²¹⁸Po and subsequent decay products. The model also indicates a slow uptake of radionuclides by the tree roots, with timescales in the order of years, leading to different dose rates for young and mature trees. The importance of foliar surface deposition, leading to a dominance of surface doses to the tree needles, is also highlighted. These mechanisms, ignored in most assessment models, are necessary improvements for assessment tools dealing with the impact of radon and its progeny in forests, with regard to legacy sites with ²²⁶Ra contamination.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107607"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142894814","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":"Preferential adsorption of noble gases in zeolitic tuff with variable saturation: A modeling study of counter-intuitive diffusive-adsorptive behavior","authors":"John P. Ortiz ,&nbsp;Chelsea W. Neil ,&nbsp;Harihar Rajaram ,&nbsp;Hakim Boukhalfa ,&nbsp;Philip H. Stauffer","doi":"10.1016/j.jenvrad.2024.107608","DOIUrl":"10.1016/j.jenvrad.2024.107608","url":null,"abstract":"<div><div>Noble gas transport through geologic media has important applications in the prediction and characterization of measured gas signatures related to underground nuclear explosions (UNEs). Retarding processes such as adsorption can cause significant species fractionation of radionuclide gases, which has implications for measured and predicted signatures used to distinguish radioxenon originating from civilian nuclear facilities or from UNEs. Accounting for the effects of variable water saturation in geologic media on tracer transport is one of the most challenging aspects of modeling gas transport because there is no unifying relationship for the associated tortuosity changes between different rock types, and reactive transport processes such as adsorption that are affected by the presence of water likewise behave differently between gas species. In this study, we perform numerical diffusive-adsorptive transport simulations to estimate gas transport parameters associated with bench-scale laboratory diffusion cell experiments measuring breakthrough in zeolitic and non-zeolitic rocks for a gaseous mixture of xenon, krypton, and SF<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span> at varying degrees of water saturation (<span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub></math></span>). Counter-intuitive transport behavior was observed in the zeolitic rock experiments whereby breakthrough concentrations were significantly higher when the core was partially saturated (<span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>=</mo><mn>17</mn></mrow></math></span>%) than under dry (<span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>=</mo><mn>0</mn></mrow></math></span>%) conditions. Breakthrough of xenon was especially retarded in the dry core – likely due to comparatively high affinity of xenon for zeolitic adsorption sites – and estimated effective diffusion coefficients for all gases were approximately an order of magnitude lower than what is predicted by porosity-tortuosity models. We propose the counter-intuitive behavior observed is because water infiltration of zeolite nanopores reduces both the adsorptive capacity of the rock and the tortuosity of connected flow paths. We developed a two-site competitive kinetic Langmuir adsorption reaction for the porous media transport simulator in order to constrain transport parameters within zeolitic tuff, where differential adsorption to zeolite and non-zeolite pores was observed. We determined that liquid saturation-dependent diffusive-adsorptive transport is affected by subtle and at times competing processes that are specific to different gases, which have a significant overall influence on effective transport parameters.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"282 ","pages":"Article 107608"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142921137","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}