Pub Date : 2025-10-11DOI: 10.1016/j.jenvrad.2025.107834
Ilia Yarmoshenko, Vyacheslav Izgagin , Michael Zhukovsky
The article presents estimates of the annual effective doses received by residents of multi-story residential buildings constructed after the year 2000 and classified as energy-efficient. The assessments cover nine major cities across Russia and focus on external and internal exposure. The calculations are based on field measurements, including non-destructive assessments of the average concentration of 226Ra, 232Th and 40K and effective dose rate, as well as concentrations of radon and the equilibrium equivalent thoron concentration within contemporary high-rise buildings. The average annual effective dose from external exposure for the surveyed cities was found to be 0.27 mSv, while the internal exposure attributable to radon and its progeny amounted to 0.90 mSv, and that from thoron progeny was estimated at 0.31 mSv.
{"title":"Primary sources of population radiation exposure in multi-story residential buildings in large Russian cities","authors":"Ilia Yarmoshenko, Vyacheslav Izgagin , Michael Zhukovsky","doi":"10.1016/j.jenvrad.2025.107834","DOIUrl":"10.1016/j.jenvrad.2025.107834","url":null,"abstract":"<div><div>The article presents estimates of the annual effective doses received by residents of multi-story residential buildings constructed after the year 2000 and classified as energy-efficient. The assessments cover nine major cities across Russia and focus on external and internal exposure. The calculations are based on field measurements, including non-destructive assessments of the average concentration of <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K and effective dose rate, as well as concentrations of radon and the equilibrium equivalent thoron concentration within contemporary high-rise buildings. The average annual effective dose from external exposure for the surveyed cities was found to be 0.27 mSv, while the internal exposure attributable to radon and its progeny amounted to 0.90 mSv, and that from thoron progeny was estimated at 0.31 mSv.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107834"},"PeriodicalIF":2.1,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145280378","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}
Pub Date : 2025-10-09DOI: 10.1016/j.jenvrad.2025.107831
José M. Abril-Hernández
Interpreting the depth distributions of radionuclides and other tracers in recent sediments is a key point in many environmental studies. There are cases of large penetration depths that cannot be explained by the kinetic reactive transport of the tracers in the dissolved phase. The cotransport of colloids and tracers has been studied in the context of column experiments, with a focus on the effluent. This work aims to develop a Lagrangian model for the cotransport of colloids and tracers in natural aquatic sediments, with a focus on their retention and the resulting depth distribution patterns. It makes plausible estimates of the magnitudes involved and studies their roles using real data from a variety of sedimentary environments. The retention coefficient for colloids is orders of magnitude lower than direct kinetic coefficients for the liquid-solid uptake and it co-varies with the dispersive transport, resulting in large penetration depths in times ranging from a few hours to a few months. The above depth distributions are used in a model of composite fluxes that operates at a centennial scale, as illustrated with fallout radionuclides using real core data. This can explain flattening and subsurface maxima in 210Pbexc profiles, and large penetration tails of high- radionuclides that, when ignored, can lead to misuses of the 210Pb dating models. In these examples, the colloidal bound fraction of the tracers ranged from 20 % to 40 %. These percentages are reliable in many aquatic environments, as supported by data from the literature.
{"title":"Modelling cotransport of colloids and tracers in surficial sediments: applications to fallout radionuclides","authors":"José M. Abril-Hernández","doi":"10.1016/j.jenvrad.2025.107831","DOIUrl":"10.1016/j.jenvrad.2025.107831","url":null,"abstract":"<div><div>Interpreting the depth distributions of radionuclides and other tracers in recent sediments is a key point in many environmental studies. There are cases of large penetration depths that cannot be explained by the kinetic reactive transport of the tracers in the dissolved phase. The cotransport of colloids and tracers has been studied in the context of column experiments, with a focus on the effluent. This work aims to develop a Lagrangian model for the cotransport of colloids and tracers in natural aquatic sediments, with a focus on their retention and the resulting depth distribution patterns. It makes plausible estimates of the magnitudes involved and studies their roles using real data from a variety of sedimentary environments. The retention coefficient for colloids is orders of magnitude lower than direct kinetic coefficients for the liquid-solid uptake and it co-varies with the dispersive transport, resulting in large penetration depths in times ranging from a few hours to a few months. The above depth distributions are used in a model of composite fluxes that operates at a centennial scale, as illustrated with fallout radionuclides using real core data. This can explain flattening and subsurface maxima in <sup>210</sup>Pb<sub>exc</sub> profiles, and large penetration tails of high-<span><math><mrow><msub><mi>k</mi><mi>d</mi></msub></mrow></math></span> radionuclides that, when ignored, can lead to misuses of the <sup>210</sup>Pb dating models. In these examples, the colloidal bound fraction of the tracers ranged from 20 % to 40 %. These percentages are reliable in many aquatic environments, as supported by data from the literature.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107831"},"PeriodicalIF":2.1,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269963","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}
Gamma-ray detectors that are deployed outdoors experience increased event rates during precipitation due to the attendant increase in Rn-222 progeny at ground level. The increased radiation due to these decay products (Pb-214 and Bi-214) has been studied for many decades in applications such as atmospheric science and radiation protection. For those applications radon progeny signatures are the signal of interest, while in the fields of radiological and nuclear security and aerial radiological mapping they are a nuisance. When searching for radiological contamination or missing sources, an analyst must take precipitation into account to reduce false alarms, in addition to accounting for static background signatures. To train advanced search algorithms, an effort has been underway to generate synthetic gamma-ray event data that represent a realistic urban area, including occasional rain events to add to the realism. This manuscript describes an effort to analyze and model gamma-ray spectra measured during rainfall by a NaI(Tl) detector located outdoors in order to derive accurate source terms for Pb-214 and Bi-214 at a high frequency (less than 1 min). All known sources of background were quantitatively modeled across the full gamma-ray spectrum, so that the Pb-214 and Bi-214 activity concentrations on the ground could be inferred from a linear model fit to each spectrum. A physically motivated model was applied to the data to further smooth the fits, which had the benefit of yielding information about the concentrations of the progeny in rainwater and their apparent age, making this the first time full-spectrum modeling has been used for continuous measurements of radon progeny. Full-spectrum modeling’s ability to leverage more statistics allows for measurements at a rate of more than once per minute, rather than the more typical 10- or 15 min measurement cycle, and therefore this approach could lead to studies of radon progeny on shorter timescales than previously possible.
{"title":"Full spectrum modeling of in situ gamma-ray detector measurements with a focus on precipitation-induced transients","authors":"M.S. Bandstra , J.M. Ghawaly , D.E. Peplow , D.E. Archer , B.J. Quiter , T.H.Y. Joshi , A.D. Nicholson , M.J. Willis , I. Garishvili , A.J. Rowe , B.R. Longmire , J.T. Nattress","doi":"10.1016/j.jenvrad.2025.107826","DOIUrl":"10.1016/j.jenvrad.2025.107826","url":null,"abstract":"<div><div>Gamma-ray detectors that are deployed outdoors experience increased event rates during precipitation due to the attendant increase in Rn-222 progeny at ground level. The increased radiation due to these decay products (Pb-214 and Bi-214) has been studied for many decades in applications such as atmospheric science and radiation protection. For those applications radon progeny signatures are the signal of interest, while in the fields of radiological and nuclear security and aerial radiological mapping they are a nuisance. When searching for radiological contamination or missing sources, an analyst must take precipitation into account to reduce false alarms, in addition to accounting for static background signatures. To train advanced search algorithms, an effort has been underway to generate synthetic gamma-ray event data that represent a realistic urban area, including occasional rain events to add to the realism. This manuscript describes an effort to analyze and model gamma-ray spectra measured during rainfall by a NaI(Tl) detector located outdoors in order to derive accurate source terms for Pb-214 and Bi-214 at a high frequency (less than 1 min). All known sources of background were quantitatively modeled across the full gamma-ray spectrum, so that the Pb-214 and Bi-214 activity concentrations on the ground could be inferred from a linear model fit to each spectrum. A physically motivated model was applied to the data to further smooth the fits, which had the benefit of yielding information about the concentrations of the progeny in rainwater and their apparent age, making this the first time full-spectrum modeling has been used for continuous measurements of radon progeny. Full-spectrum modeling’s ability to leverage more statistics allows for measurements at a rate of more than once per minute, rather than the more typical 10- or 15 min measurement cycle, and therefore this approach could lead to studies of radon progeny on shorter timescales than previously possible.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107826"},"PeriodicalIF":2.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145258307","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}
Pub Date : 2025-10-08DOI: 10.1016/j.jenvrad.2025.107827
Atsushi Hirano , Hidenori Kagamifuchi , Ken Koyabu , Koichi Takizawa , Yuichi Onda
This study investigates the seasonal variation in radioactive cesium (sum of ′134Cs and ′137Cs; hereafter radioactive Cs) concentrations in kokanee (Oncorhynchus nerka) within a pumped-storage power plant reservoir system, with particular focus on the marked decline in radioactive Cs levels during plant operation. Radioactive Cs transfer pathways to kokanee were examined in relation to water residence time, vertical temperature profiles, and water quality under operational and non-operational conditions. Two primary pathways originating from the contaminated forest surrounding the reservoir were identified. The first involves suspended detritus, primarily decomposed forest litter, which accumulates at the thermocline and facilitates Cs transfer to kokanee via interactions with plankton. The second pathway involves detritus deposited on the lakebed, consumed by chironomids, which serve as prey for kokanee. Radioactive Cs concentrations in chironomids were higher than those in plankton, suggesting that seasonal dietary shifts in kokanee contribute to observed variations in radioactive Cs accumulation. Power plant operations can transport part of the contaminated detritus accumulated at the thermocline out of the lake, thereby inhibiting its sedimentation on the lake bottom, reducing radioactive Cs availability to lower trophic organisms, and resulting in a marked reduction of radioactive Cs concentrations in kokanee. These findings highlight the influence of anthropogenic operations on Cs dynamics in aquatic ecosystems and have important implications for ecological risk assessment and the management of radiological contamination.
{"title":"Operations of a pumped storage power plant attenuated radioactive Cs concentration in kokanee stocked in the upper reservoir","authors":"Atsushi Hirano , Hidenori Kagamifuchi , Ken Koyabu , Koichi Takizawa , Yuichi Onda","doi":"10.1016/j.jenvrad.2025.107827","DOIUrl":"10.1016/j.jenvrad.2025.107827","url":null,"abstract":"<div><div>This study investigates the seasonal variation in radioactive cesium (sum of ′134Cs and ′137Cs; hereafter radioactive Cs) concentrations in kokanee (<em>Oncorhynchus nerka</em>) within a pumped-storage power plant reservoir system, with particular focus on the marked decline in radioactive Cs levels during plant operation. Radioactive Cs transfer pathways to kokanee were examined in relation to water residence time, vertical temperature profiles, and water quality under operational and non-operational conditions. Two primary pathways originating from the contaminated forest surrounding the reservoir were identified. The first involves suspended detritus, primarily decomposed forest litter, which accumulates at the thermocline and facilitates Cs transfer to kokanee via interactions with plankton. The second pathway involves detritus deposited on the lakebed, consumed by chironomids, which serve as prey for kokanee. Radioactive Cs concentrations in chironomids were higher than those in plankton, suggesting that seasonal dietary shifts in kokanee contribute to observed variations in radioactive Cs accumulation. Power plant operations can transport part of the contaminated detritus accumulated at the thermocline out of the lake, thereby inhibiting its sedimentation on the lake bottom, reducing radioactive Cs availability to lower trophic organisms, and resulting in a marked reduction of radioactive Cs concentrations in kokanee. These findings highlight the influence of anthropogenic operations on Cs dynamics in aquatic ecosystems and have important implications for ecological risk assessment and the management of radiological contamination.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107827"},"PeriodicalIF":2.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145258377","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}
Pub Date : 2025-10-07DOI: 10.1016/j.jenvrad.2025.107789
Imam Ghazali Yasmint , Yo Ishigaki , Kayoko Yamamoto
Following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, environmental radiation monitoring is crucial for supporting reconstruction programs and ensuring the safety of returning residents. Although government-led monitoring systems yield relatively accurate data, limited coverage exists in some areas. Consequently, citizen-science initiatives, such as Safecast, emerged to address these gaps. We compare two major radiation monitoring systems in Fukushima Prefecture over the period 2019–2023: the Kyoto University Radiation Mapping (KURAMA) system and Safecast. As measurements are not co-located, all readings were aggregated onto a uniform 100 × 100 m grid for spatial comparison. At the current low ambient-dose levels, a nearly constant contribution from secondary cosmic radiation can measurably inflate readings from Geiger–Müller (GM) detectors. The analysis examines spatial coverage, radiation dose rate distribution, and data fitting through linear regression, error analysis, and Bland–Altman analysis. The results show that KURAMA provides extensive area coverage (1068–1419 km2 per year) with sharp radiation dose transitions, particularly in high-exposure areas. In contrast, Safecast encompasses approximately 10 % of the area surveyed annually by KURAMA. We found that some Safecast areas cover residential areas and public facilities not monitored by KURAMA. Regression analysis indicates a strong linear correlation (R2 = 0.8034). It also reveals a systematic bias in uncorrected Safecast data, yielding higher doses in low-exposure areas (<0.5 μSv/h) and lower doses in high-exposure areas (>1.0 μSv/h) compared to KURAMA. A key driver of the low-dose overestimation is the 31 nSv/h contribution of secondary cosmic radiation inherently counted by Safecast's GM detector. Subtracting this constant background (yielding Safecast_CR) lowers the Safecast median from 0.127 to 0.096 μSv/h and improves low-dose agreement with KURAMA while not changing the R2 value. This claim of systematic bias is further strengthened by additional statistical analysis showing a consistent pattern of measurement discrepancies. These differences are influenced by detector characteristics, data collection methods, and operational variability, including the cosmic-ray component. Our findings indicate that integrating both systems, with appropriate calibration of Safecast data, can enhance the accuracy of radiation exposure assessments, improve post-decontamination monitoring, and contribute to more representative radiation maps for public safety and policy-making.
{"title":"KURAMA vs. Safecast: Radiation data comparison in Fukushima following whole-area decontamination","authors":"Imam Ghazali Yasmint , Yo Ishigaki , Kayoko Yamamoto","doi":"10.1016/j.jenvrad.2025.107789","DOIUrl":"10.1016/j.jenvrad.2025.107789","url":null,"abstract":"<div><div>Following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, environmental radiation monitoring is crucial for supporting reconstruction programs and ensuring the safety of returning residents. Although government-led monitoring systems yield relatively accurate data, limited coverage exists in some areas. Consequently, citizen-science initiatives, such as Safecast, emerged to address these gaps. We compare two major radiation monitoring systems in Fukushima Prefecture over the period 2019–2023: the Kyoto University Radiation Mapping (KURAMA) system and Safecast. As measurements are not co-located, all readings were aggregated onto a uniform 100 × 100 m grid for spatial comparison. At the current low ambient-dose levels, a nearly constant contribution from secondary cosmic radiation can measurably inflate readings from Geiger–Müller (GM) detectors. The analysis examines spatial coverage, radiation dose rate distribution, and data fitting through linear regression, error analysis, and Bland–Altman analysis. The results show that KURAMA provides extensive area coverage (1068–1419 km<sup>2</sup> per year) with sharp radiation dose transitions, particularly in high-exposure areas. In contrast, Safecast encompasses approximately 10 % of the area surveyed annually by KURAMA. We found that some Safecast areas cover residential areas and public facilities not monitored by KURAMA. Regression analysis indicates a strong linear correlation (R<sup>2</sup> = 0.8034). It also reveals a systematic bias in uncorrected Safecast data, yielding higher doses in low-exposure areas (<0.5 μSv/h) and lower doses in high-exposure areas (>1.0 μSv/h) compared to KURAMA. A key driver of the low-dose overestimation is the 31 nSv/h contribution of secondary cosmic radiation inherently counted by Safecast's GM detector. Subtracting this constant background (yielding Safecast_CR) lowers the Safecast median from 0.127 to 0.096 μSv/h and improves low-dose agreement with KURAMA while not changing the R<sup>2</sup> value. This claim of systematic bias is further strengthened by additional statistical analysis showing a consistent pattern of measurement discrepancies. These differences are influenced by detector characteristics, data collection methods, and operational variability, including the cosmic-ray component. Our findings indicate that integrating both systems, with appropriate calibration of Safecast data, can enhance the accuracy of radiation exposure assessments, improve post-decontamination monitoring, and contribute to more representative radiation maps for public safety and policy-making.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107789"},"PeriodicalIF":2.1,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251378","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}
Pub Date : 2025-10-04DOI: 10.1016/j.jenvrad.2025.107829
Ramesh S. Sarathi , Paul W. Eslinger , Douglas J. Baxter , Nipun Gunawardena , Donald D. Lucas , Michael F. Mayer , Brian D. Milbrath , Brian T. Schrom
A nuclear explosion screening exercise in 2023 (Maurer et al., 2023) found challenges with discerning anomalous radioxenon activity concentrations relative to elevated background concentrations. Research has continued into methods to detect anomalous radioxenon concentrations by comparing samples to estimates of atmospheric radioxenon background concentrations caused by releases at nuclear reactors or medical isotope production facilities. A new approach estimates the sample concentrations using time-varying radioxenon release rates obtained using optimization techniques that constrain the facility release rates to plausible amounts based on historical data or facility knowledge. The purpose of the optimization is to determine whether any combination of plausible release rates from emitting facilities can explain a series of radioxenon measurements at one or more sampling stations. A case study uses radioxenon data collected at three locations in western Europe for a month in 2021 and considers releases from 77 locations. Fewer samples are identified as being anomalous using a simplistic flagging rule than from an application of the current International Monitoring System (IMS) activity concentration-level rule.
{"title":"Incorporating civilian radioxenon background estimates in anomaly detection","authors":"Ramesh S. Sarathi , Paul W. Eslinger , Douglas J. Baxter , Nipun Gunawardena , Donald D. Lucas , Michael F. Mayer , Brian D. Milbrath , Brian T. Schrom","doi":"10.1016/j.jenvrad.2025.107829","DOIUrl":"10.1016/j.jenvrad.2025.107829","url":null,"abstract":"<div><div>A nuclear explosion screening exercise in 2023 (Maurer et al., 2023) found challenges with discerning anomalous radioxenon activity concentrations relative to elevated background concentrations. Research has continued into methods to detect anomalous radioxenon concentrations by comparing samples to estimates of atmospheric radioxenon background concentrations caused by releases at nuclear reactors or medical isotope production facilities. A new approach estimates the sample concentrations using time-varying radioxenon release rates obtained using optimization techniques that constrain the facility release rates to plausible amounts based on historical data or facility knowledge. The purpose of the optimization is to determine whether any combination of plausible release rates from emitting facilities can explain a series of radioxenon measurements at one or more sampling stations. A case study uses radioxenon data collected at three locations in western Europe for a month in 2021 and considers releases from 77 locations. Fewer samples are identified as being anomalous using a simplistic flagging rule than from an application of the current International Monitoring System (IMS) activity concentration-level rule.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107829"},"PeriodicalIF":2.1,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223360","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}
Pub Date : 2025-10-01Epub Date: 2025-08-07DOI: 10.1016/j.jenvrad.2025.107767
F van Niekerk, P Jones, S Woodborne, R Newman
Gamma-ray spectrometry, primarily utilising NaI(Tl) detectors, is widely used to measure naturally occurring radionuclides in terrestrial environments, but the use of LaBr3(Ce) detectors is gaining prominence. Traditionally limited to vehicle-based deployments, access to hostile sites with elevated radiation has been restricted. This study demonstrates the effectiveness of a mobile radiation detection unit (MRDU) equipped with a LaBr3(Ce) detector in such environments. The uranium Minimum Detectable Activity was 236 (16) Bq/kg at 1764.5 keV. The MRDU was deployed at the Welverdiend Agricultural Holdings, where elevated uranium levels are expected due to historic gold mining activities in the area., and the uranium activity was measured at 6477 Bq/kg. The uranium disequilibrium was investigated by comparing gamma radiation results with the total uranium concentration obtained through chemical analysis. The comparison confirmed the presence of uranium disequilibrium.
{"title":"A mobile gamma-ray LaBr<sub>3</sub>(Ce) detector unit for in-situ radionuclide analysis at TENORM contamination sites.","authors":"F van Niekerk, P Jones, S Woodborne, R Newman","doi":"10.1016/j.jenvrad.2025.107767","DOIUrl":"10.1016/j.jenvrad.2025.107767","url":null,"abstract":"<p><p>Gamma-ray spectrometry, primarily utilising NaI(Tl) detectors, is widely used to measure naturally occurring radionuclides in terrestrial environments, but the use of LaBr<sub>3</sub>(Ce) detectors is gaining prominence. Traditionally limited to vehicle-based deployments, access to hostile sites with elevated radiation has been restricted. This study demonstrates the effectiveness of a mobile radiation detection unit (MRDU) equipped with a LaBr<sub>3</sub>(Ce) detector in such environments. The uranium Minimum Detectable Activity was 236 (16) Bq/kg at 1764.5 keV. The MRDU was deployed at the Welverdiend Agricultural Holdings, where elevated uranium levels are expected due to historic gold mining activities in the area., and the uranium activity was measured at 6477 Bq/kg. The uranium disequilibrium was investigated by comparing gamma radiation results with the total uranium concentration obtained through chemical analysis. The comparison confirmed the presence of uranium disequilibrium.</p>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"289 ","pages":"107767"},"PeriodicalIF":2.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144804240","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}
Pub Date : 2025-10-01Epub Date: 2025-08-06DOI: 10.1016/j.jenvrad.2025.107768
Jaeeun Lee, Hyunmi Lee, Jin Young Choi, Ji Hyun Lee, Intae Kim
This study examined the annual and seasonal variations of 210Pb in aerosols collected in Busan, a major port city in South Korea. Aerosol samples were obtained during two sampling campaigns: (i) total suspended particles (TSP) from April 2019 to February 2020, and (ii) particulate matter with diameters ≤10 μm (PM10) and ≤2.5 μm (PM2.5) from March 2020 to February 2021. The activity concentrations of 210Pb ranged from 0.10 to 1.98 mBq m-3 (TSP), 0.09-1.97 mBq m-3 (PM10), and 0.02-2.07 mBq m-3 (PM2.5), showing clear seasonal trends. Activities peaked in autumn and winter (October-February) and were lowest in summer (July-September), with up to two-fold seasonal variation. These patterns were mainly attributed to meteorological variability and increased anthropogenic emissions during colder months due to seasonal wind shifts. No significant differences in 210Pb activity appeared among size-fractionated samples (TSP, PM10, and PM2.5), indicating a preferential association of 210Pb with fine aerosols. Dry deposition fluxes of 210Pb in Busan were comparable to those reported in other global cities, despite only including the dry component. 210Pb activities in TSP correlated with 40K in fallout dust, likely from resuspended soil, while 210Pb in PM2.5 paralleled 7Be variations in air. Moreover, 210Pb/Pb ratios showed seasonal changes, notably in PM2.5 during the dry season. The results suggest that aerosol behavior in Busan is notably influenced by anthropogenic sources during dry months, especially in fine dust (e.g., PM2.5). Overall, 210Pb proves useful as a radioactive tracer for understanding aerosol dynamics.
{"title":"Annual distribution and deposition of atmospheric <sup>210</sup>Pb in Busan, the largest port city in Korea.","authors":"Jaeeun Lee, Hyunmi Lee, Jin Young Choi, Ji Hyun Lee, Intae Kim","doi":"10.1016/j.jenvrad.2025.107768","DOIUrl":"10.1016/j.jenvrad.2025.107768","url":null,"abstract":"<p><p>This study examined the annual and seasonal variations of <sup>210</sup>Pb in aerosols collected in Busan, a major port city in South Korea. Aerosol samples were obtained during two sampling campaigns: (i) total suspended particles (TSP) from April 2019 to February 2020, and (ii) particulate matter with diameters ≤10 μm (PM<sub>10</sub>) and ≤2.5 μm (PM<sub>2.5</sub>) from March 2020 to February 2021. The activity concentrations of <sup>210</sup>Pb ranged from 0.10 to 1.98 mBq m<sup>-3</sup> (TSP), 0.09-1.97 mBq m<sup>-3</sup> (PM<sub>10</sub>), and 0.02-2.07 mBq m<sup>-3</sup> (PM<sub>2.5</sub>), showing clear seasonal trends. Activities peaked in autumn and winter (October-February) and were lowest in summer (July-September), with up to two-fold seasonal variation. These patterns were mainly attributed to meteorological variability and increased anthropogenic emissions during colder months due to seasonal wind shifts. No significant differences in <sup>210</sup>Pb activity appeared among size-fractionated samples (TSP, PM<sub>10</sub>, and PM<sub>2.5</sub>), indicating a preferential association of <sup>210</sup>Pb with fine aerosols. Dry deposition fluxes of <sup>210</sup>Pb in Busan were comparable to those reported in other global cities, despite only including the dry component. <sup>210</sup>Pb activities in TSP correlated with <sup>40</sup>K in fallout dust, likely from resuspended soil, while <sup>210</sup>Pb in PM<sub>2.5</sub> paralleled <sup>7</sup>Be variations in air. Moreover, <sup>210</sup>Pb/Pb ratios showed seasonal changes, notably in PM<sub>2.5</sub> during the dry season. The results suggest that aerosol behavior in Busan is notably influenced by anthropogenic sources during dry months, especially in fine dust (e.g., PM<sub>2.5</sub>). Overall, <sup>210</sup>Pb proves useful as a radioactive tracer for understanding aerosol dynamics.</p>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"289 ","pages":"107768"},"PeriodicalIF":2.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144799276","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}
Pub Date : 2025-09-30DOI: 10.1016/j.jenvrad.2025.107797
Zhiyuan Shi , Kimikazu Sasa , Masumi Matsumura , Tsutomu Takahashi , Yuichi Takaku , Michinobu Kuwae , Shinya Yamasaki , Keisuke Sueki , Aya Sakaguchi
Anthropogenic 129I has been used as a powerful tool for tracing human nuclear activities. This study measured 127I concentrations and 129I/127I ratios in a sediment core from Beppu Bay, Japan, to evaluate the potential of 129I as a key marker for the Anthropocene. The 129I/127I ratios ranged from 1.16 × 10−11 to 1.11 × 10−10 and showed a clear increase in the 1950s, consistent with the beginning of global nuclear activities. This variation agrees with previously reported records from East Asia. Owing to the high sedimentation rate, well-preserved lamination, and redox conditions in Beppu Bay, the core retained both global increase of anthropogenic 129I and several distinct local short-term peaks of local origin. The timeline of these peaks are likely to coincides to local volcanic eruptions and extreme weather events that enhanced 129I/127I, and slightly elevated 129I/127I ratio in pre-nuclear layers suggest limited post-depositional migration under reducing conditions. Overall, the Beppu Bay core provides a high-resolution and well-dated record of 129I deposition influenced by both global and local signals. These results support the potential of 129I as a key marker in coastal marine environments for defining the Anthropocene.
{"title":"Isotopic composition of 129I in marine sediments from Beppu Bay: assessing its feasibility as an Anthropocene marker","authors":"Zhiyuan Shi , Kimikazu Sasa , Masumi Matsumura , Tsutomu Takahashi , Yuichi Takaku , Michinobu Kuwae , Shinya Yamasaki , Keisuke Sueki , Aya Sakaguchi","doi":"10.1016/j.jenvrad.2025.107797","DOIUrl":"10.1016/j.jenvrad.2025.107797","url":null,"abstract":"<div><div>Anthropogenic <sup>129</sup>I has been used as a powerful tool for tracing human nuclear activities. This study measured <sup>127</sup>I concentrations and <sup>129</sup>I/<sup>127</sup>I ratios in a sediment core from Beppu Bay, Japan, to evaluate the potential of <sup>129</sup>I as a key marker for the Anthropocene. The <sup>129</sup>I/<sup>127</sup>I ratios ranged from 1.16 × 10<sup>−11</sup> to 1.11 × 10<sup>−10</sup> and showed a clear increase in the 1950s, consistent with the beginning of global nuclear activities. This variation agrees with previously reported records from East Asia. Owing to the high sedimentation rate, well-preserved lamination, and redox conditions in Beppu Bay, the core retained both global increase of anthropogenic <sup>129</sup>I and several distinct local short-term peaks of local origin. The timeline of these peaks are likely to coincides to local volcanic eruptions and extreme weather events that enhanced <sup>129</sup>I/<sup>127</sup>I, and slightly elevated <sup>129</sup>I/<sup>127</sup>I ratio in pre-nuclear layers suggest limited post-depositional migration under reducing conditions. Overall, the Beppu Bay core provides a high-resolution and well-dated record of <sup>129</sup>I deposition influenced by both global and local signals. These results support the potential of <sup>129</sup>I as a key marker in coastal marine environments for defining the Anthropocene.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107797"},"PeriodicalIF":2.1,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206576","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}
Pub Date : 2025-09-26DOI: 10.1016/j.jenvrad.2025.107817
Junni He , Minghua Lyu , Zhixin Qiu , Xin He , Bo Lu , Jia Wang , Shifei Shen , Xiaole Zhang
Timely and accurate radiation dose assessment is essential for effective emergency response in nuclear accidents. However, meteorological uncertainties, especially in wind data, can lead to substantial discrepancies between simulated and observed plume behaviors, compromising situational awareness and decision-making. This study proposed a physics-informed optimization framework that integrates a physical radiation assessment model with a genetic algorithm to dynamically correct time-series wind field data and mitigate discrepancies caused by meteorological uncertainty. The physical model couples the Lagrangian puff model with the point kernel integration method. To improve efficiency, a dimensionality reduction approach simplifies the three-dimensional gamma dose integration to one dimension. The proposed framework was validated using the first venting scenario of Unit 1 at the Fukushima Daiichi Nuclear Power Plant. The temporal optimization significantly enhanced the alignment of estimated and observed plume passage times. Quantitatively, the optimization respectively reduces the fractional bias (FB) and the normalized mean square error (NMSE) at the Main Gate by 57.82 % and 90.69 %, while the improvements at MP8 station reached 97.88 % (FB) and 92.19 % (NMSE). The FAC2 (Fraction of predictions within a factor of two) at the Main Gate increased substantially from 9.5 % to 52.4 % post-optimization. These improvements demonstrate the effectiveness of the proposed method in enhancing predictive accuracy for emergency radiation dose assessment and optimizing operational decision-making under complex atmospheric conditions.
{"title":"Physics-informed optimization for emergency radiation assessment with temporal correction under meteorological uncertainty","authors":"Junni He , Minghua Lyu , Zhixin Qiu , Xin He , Bo Lu , Jia Wang , Shifei Shen , Xiaole Zhang","doi":"10.1016/j.jenvrad.2025.107817","DOIUrl":"10.1016/j.jenvrad.2025.107817","url":null,"abstract":"<div><div>Timely and accurate radiation dose assessment is essential for effective emergency response in nuclear accidents. However, meteorological uncertainties, especially in wind data, can lead to substantial discrepancies between simulated and observed plume behaviors, compromising situational awareness and decision-making. This study proposed a physics-informed optimization framework that integrates a physical radiation assessment model with a genetic algorithm to dynamically correct time-series wind field data and mitigate discrepancies caused by meteorological uncertainty. The physical model couples the Lagrangian puff model with the point kernel integration method. To improve efficiency, a dimensionality reduction approach simplifies the three-dimensional gamma dose integration to one dimension. The proposed framework was validated using the first venting scenario of Unit 1 at the Fukushima Daiichi Nuclear Power Plant. The temporal optimization significantly enhanced the alignment of estimated and observed plume passage times. Quantitatively, the optimization respectively reduces the fractional bias (FB) and the normalized mean square error (NMSE) at the Main Gate by 57.82 % and 90.69 %, while the improvements at MP8 station reached 97.88 % (FB) and 92.19 % (NMSE). The FAC2 (Fraction of predictions within a factor of two) at the Main Gate increased substantially from 9.5 % to 52.4 % post-optimization. These improvements demonstrate the effectiveness of the proposed method in enhancing predictive accuracy for emergency radiation dose assessment and optimizing operational decision-making under complex atmospheric conditions.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"291 ","pages":"Article 107817"},"PeriodicalIF":2.1,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157266","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号