Journal of environmental radioactivity最新文献

{"title":"210Pb-based dating models for recent sediments. A review","authors":"José M. Abril-Hernández","doi":"10.1016/j.jenvrad.2025.107749","DOIUrl":"10.1016/j.jenvrad.2025.107749","url":null,"abstract":"<div><div>The ²¹⁰Pb-based dating method provides absolute ages determination in recent aquatic sediments at centennial scales. It is widely used to support a large variety of environmental studies. However, any empirical data set is compatible with an infinite number of chronologies that need to be constrained by a series of assumptions (models) on the particular sedimentary conditions of the studied environment, and validated with independent chronostratigraphic markers. During five decades, about thirty models have been developed to cope with the wide diversity of natural conditions, a good number of them appearing in recent years, along with new concepts such as model errors, attractors for χ-mapping, or kinetic reactive transport, which have changed common views and practices. This paper aims to present a comprehensive review of this dating method to provide to final users updated tools and a renewed understanding to improve the reliability of their applications. Models are classified in terms of their assumptions on the sedimentary systems, which are better understood from a revisited theory of early compaction and the description of the microcosms of saturated porous media, where composite fluxes of tracers undergo different deposition pathways in terms of physical and kinetic reactive transport. The article reviews empirical evidence on the natural variability in mass flows and initial activity concentrations. Some models allow analytical solutions, while others require numerical techniques. The review is illustrated with examples from real case studies.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"289 ","pages":"Article 107749"},"PeriodicalIF":1.9,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523947","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":"Anthropogenic tritium as indicator for groundwater inflow into major rivers – Potentials and challenges of a tracer application","authors":"Michael Schubert ,&nbsp;Christin Müller ,&nbsp;Kay Knoeller ,&nbsp;Eva Juranová","doi":"10.1016/j.jenvrad.2025.107745","DOIUrl":"10.1016/j.jenvrad.2025.107745","url":null,"abstract":"<div><div>The inflow of groundwater into a large river can contribute significantly to the total discharge of the river. Especially at low river water level, the inflowing groundwater can strongly influence the river water quality. Therefore, both the localisation and quantification of groundwater inflow into rivers is essential for their sustainable management. Corresponding field investigations usually rely on tracer applications based on stable water isotopes (δ²H/δ¹⁸O), naturally occurring radioisotopes (e.g. ²²²Rn) and standard water parameters (T, pH, EC). However, an extension of this tracer toolbox is desirable. In recent studies, the idea of using anthropogenic tritium that is released from a nuclear power plant (NPP) at an upstream location as an additional tracer has been pursued. The concept assumes that the inflow of (practically tritium-free) groundwater and tributary water dilutes the anthropogenic tritium inventory of the river and thus enables quantification of the total groundwater/tributary inflow (“tritium dilution concept”). Since the inflow of tributaries is usually easy to quantify, it is suggested that the inflow of groundwater can be derived from the tritium data. In the presented pilot study, we investigated the applicability of this “tritium dilution concept” and evaluated the general challenges associated to the uncertainty of input parameters. The study was executed exemplarily at an extended river section affected by the release of NPP process water (Vltava/Elbe River, Czech Republic). The evaluation of two 1-month tritium timeseries recorded at two monitoring/gauging stations 168 km apart allowed quantifying the total groundwater/tributary inflow into the river within this section based on the tritium data with a precision that was close to the gauged increase in river discharge (+72 % and +77 %, respectively). On the other hand, the groundwater inflow that was derived after subtracting the gauged tributary inflow from the quantified total water inflow was comparably low and therefore within the approaches’ range of uncertainty. From this it can be concluded that the “tritium dilution concept” is applicable if the required input parameters, namely the natural tritium groundwater/tributary endmember and the tributary discharge, are known with sufficient precision. This outcome is promising for studies that focus on less extended river sections with input parameters that are easier to define.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107745"},"PeriodicalIF":1.9,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489508","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":"Effects on the middle adult stage of the Tohoku hynobiid salamander, Hynobius lichenatus, chronically γ-irradiated from the embryonic stage","authors":"Shoichi Fuma ,&nbsp;Yumi Une ,&nbsp;Sadao Ihara","doi":"10.1016/j.jenvrad.2025.107744","DOIUrl":"10.1016/j.jenvrad.2025.107744","url":null,"abstract":"<div><div>Tohoku hynobiid salamanders, <em>Hynobius lichenatus</em> (Amphibia, Caudata), were chronically irradiated with ¹³⁷Cs γ-rays from the embryonic to the middle adult stages for over 3000 days, and the effects on survival, somatic growth (body weight increase), sexual maturation, and histological characteristics were examined. This article reports the effects observed in the middle adult stage (days 1955–3039). Irradiation at a dose rate of 34 μGy h⁻¹ had no effect on any endpoint. At 150 or 500 μGy h⁻¹, secondary sexual characteristics (tubercle at the anterior angle of the cloacal vent for males and ovisac development for females) were not observed. Gonads were either severely atrophied or unidentified by histological examination. At some peripheral liver sites, the number of haematopoietic cells was significantly reduced. Renal damage was also observed. At 500 μGy h⁻¹, somatic growth was significantly inhibited, and 74 % of individuals died due to multiorgan failure. No tumours were observed in the dead salamanders. A dose rate-response relationship obtained in this study suggests that the derived consideration reference level of the International Commission on Radiological Protection for the Reference Frog (i.e., 40–400 μGy h⁻¹) is applicable for the protection of <em>H. lichenatus</em>, and that this salamander may not have been adversely affected even in the most severely contaminated area in Fukushima, where the highest dose rate to salamanders was estimated to be 47 μGy h⁻¹ in April 2012.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107744"},"PeriodicalIF":1.9,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366359","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":"Temperature dependence on soil-soil solution distribution coefficient of radiocaesium in Japanese agricultural soils","authors":"Keiko Tagami,&nbsp;Shigeo Uchida","doi":"10.1016/j.jenvrad.2025.107743","DOIUrl":"10.1016/j.jenvrad.2025.107743","url":null,"abstract":"<div><div>Radiocaesium mobility in 40 agricultural soil samples at different temperature conditions (4–30 °C) was studied by measuring the soil-soil solution distribution coefficient, <em>K</em>_d (L/kg). Comparison of <em>K</em>_d values obtained at 10 °C and at 30 °C indicated significant differences for 36 soil samples by the one-way ANOVA test (p &lt; 0.05) with decreases in <em>K</em>_d values under the higher temperature condition. The <em>K</em>_d measurement at 4 °C was intended to minimize the soil microbial activity effect; the results were almost the same as those observed at 10 °C. From this result, it was difficult to identify the effect of microbial activity on the radiocaesium absorbability to the soil solid phase. The obtained data imply a possible seasonal change of <em>K</em>_d values in many types of soils, and the <em>K</em>_d change likely affects the radiocaesium release rate change from soil to river water during a year.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107743"},"PeriodicalIF":1.9,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364458","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":"Assessing the quasi-equilibrium distribution of Fukushima-derived radiocesium in a typical Japanese cedar forest using an isotopic approach","authors":"Vasyl Yoschenko ,&nbsp;Kenji Nanba ,&nbsp;Muyiwa Michael Orosun ,&nbsp;Jian Zhang ,&nbsp;Thomas E. Johnson","doi":"10.1016/j.jenvrad.2025.107742","DOIUrl":"10.1016/j.jenvrad.2025.107742","url":null,"abstract":"<div><div>In this study we applied an isotopic approach to assess a quasi-equilibrium of Fukushima-derived ¹³⁷Cs in a typical mature Japanese cedar forest. As of 2020, the concentrations of ¹³⁷Cs in the aboveground biomass compartments (young sapwood, rest of sapwood, heartwood, inner bark, outer bark, big branches, small branches, young foliage, and old foliage) correlated well with the equilibrium concentrations of the naturally occurring stable isotope of cesium (¹³³Cs) transferred to the aboveground biomass from the soil, indicating that a quasi-equilibrium distribution of ¹³⁷Cs has been achieved after a period of removal of the initially intercepted radiocesium from the biomass compartments. The isotope concentration ratio ¹³⁷Cs/¹³³Cs in the biomass as of 2020 is estimated as 3.6⋅10⁻⁵ (μg kg⁻¹) (μg kg⁻¹)⁻¹ (95 % confidence interval (CI): 1.6⋅10⁻⁵ – 5.6⋅10⁻⁵). The isotope inventory ratio ¹³⁷Cs/¹³³Cs in the 5-cm topsoil is slightly lower, (2.52 ± 2.39)⋅10⁻⁵ (μg kg⁻¹) (μg kg⁻¹)⁻¹, which may indicate the presence of some amounts of ¹³⁷Cs intercepted from the atmospheric fallout in March 2011 in the biomass compartments and the predominant uptake of Cs isotopes from the topsoil layer thinner than 5 cm. The total ¹³⁷Cs inventory in aboveground biomass stabilized between 2017 and 2020 at the level of (3.1 ± 1.7)% of its total inventory in the ecosystem.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107742"},"PeriodicalIF":1.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321226","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":"Measuring 210Po in natural waters: A comparison of three methods with similar results","authors":"James T. Waples,&nbsp;Gage J. Hunter ,&nbsp;Rachel A. Smith","doi":"10.1016/j.jenvrad.2025.107732","DOIUrl":"10.1016/j.jenvrad.2025.107732","url":null,"abstract":"<div><div>Oceanographers have long used ²¹⁰Po/²¹⁰Pb disequilibria to quantify flux of particulate organic matter from the surface ocean. However, recent evidence by Roca-Martí et al. (2021) found that one of two commonly used methods to concentrate polonium from a natural water sample – coprecipitation with Fe(OH)₃ – resulted in significantly lower ²¹⁰Po activities than the other method – coprecipitation with Co-APDC. In this study, we employed the two methods used by Roca-Martí et al. (2021) and our own modified Fe(OH)₃ technique to measure ²¹⁰Po in freshwater samples collected from lake, harbor, river, and bog sources. We found a non-significant bias of ≤0.5 dpm ²¹⁰Po 100 L⁻¹ between all three methods. We found no evidence that ²⁰⁹Po was not as fully equilibrated with natural ²¹⁰Po in 15 min as it was after 12 h of equilibration. And finally, we found no indication that organic complexation of dissolved ²¹⁰Po was interfering with polonium recovery. Our results do not negate the findings by Roca-Martí et al. (2021). The behavior of ²¹⁰Po in marine systems may indeed be different. However, we recommend that future studies also examine how the collection of iron precipitate and the composition and concentration of particulate organic matter might influence the recovery of absorbed ²¹⁰Po from an unfiltered water sample.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107732"},"PeriodicalIF":1.9,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297567","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":"Trends in near-surface environmental tritium concentrations at chalk river site following shut down of the NRU reactor","authors":"Volodymyr Korolevych","doi":"10.1016/j.jenvrad.2025.107739","DOIUrl":"10.1016/j.jenvrad.2025.107739","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Recovery phase following the shutdown of the National Research Universal (NRU) nuclear reactor at Canadian Nuclear Laboratories' (CNL's) Chalk River site is studied here. In 2009, NRU was shut down for a period longer than a year during reactor vessel repair and then was shut down permanently in 2018. In both cases, tritium was sampled in the atmosphere, precipitation, vegetation, and soil. Tissue free water tritium (TFWT) and organically bound tritium (OBT) were collected in plants and in tree leaves at 1 m and 2 m above the ground. Two transects connecting dry uphill locations and neighbouring swamps downhill were sampled. These study transects are located away from the reactor site and waste management areas, and as such, are expected to represent pure recovery due to dilution of local tritium in the regional geophysical compartments of atmospheric water vapour and near-surface groundwater (aided by incoming precipitation). Trends in environmental tritium at CNL following the NRU reactor shutdown were assessed and the environmental half-life of tritium was derived for near-surface strata (atmosphere, biosphere/plants, and rhizosphere/groundwater). It appears that in 4 years, pure local (pure recovery-phase) dilution of historical tritium has reached the level at which it is now tangibly affected by remote atmospheric tritium plumes coming from CNL waste management areas with southeast (SE) winds. Exclusion of episodes associated with SE wind and with remote tritium plume results in more coherent trends across sampled near-surface geophysical strata. Trend-line exponents provide T&lt;sub&gt;1/2&lt;/sub&gt; = 1.30 ± 0.24 years of environmental half-life of tritium. The role of microclimate may require further investigation, but insignificant differences between wet and dry locations observed in TFWT already imply applicability of the environmental half-life of tritium to other sites in recovery.&lt;/div&gt;&lt;div&gt;Features of the site-specific recovery process at CNL include insensitivity of OBT and groundwater HTO trends (half-life exponents) to exclusion of samples collected under the remote tritium plume, whereas atmospheric HTO and especially precipitation HTO trends (exponents) appear affected by as much as 49 % and 267 %, respectively. The sensitivity of trend for TFWT (environmental half-life exponent) was less tangible, because of only moderate 35 % decrease in exponent after exclusion of remote plume episodes. In summary, in 4 years after the NRU reactor shutdown, the drivers of tritium transfer (atmospheric HTO and precipitation HTO) are already under substantial influence of the tritium plume from remote sources at CNL, but recipient compartments of environmental tritium are either not, or are only slightly affected by the remote tritium plume. This implies recovery phase completion in the CNL atmosphere (and in precipitation washing tritium out of it), but yet unfinished recovery of recipient compartments of OBT and groundwater HTO where quasi-","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107739"},"PeriodicalIF":1.9,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280013","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":"Environmental drivers of Be-7 and K-40 deposition in South Korea: A regional analysis of meteorological and geological influences","authors":"Sojeong Bae,&nbsp;Yejin Lee,&nbsp;Seongchan Lee,&nbsp;Ki-Deuk Byun,&nbsp;Ku Kang","doi":"10.1016/j.jenvrad.2025.107725","DOIUrl":"10.1016/j.jenvrad.2025.107725","url":null,"abstract":"<div><div>This study examines the regional behavior of two naturally occurring radionuclides – beryllium-7 (Be-7) and potassium-40 (K-40) – across 15 locations in South Korea from 2014 to 2022. Using one-way ANOVA and Pearson correlation analysis, we evaluated how meteorological and geological factors influence the deposition and rainfall concentrations of these radionuclides. Be-7 deposition showed strong associations with rainfall, fine dust concentration, wind speed, and solar cycle activity, reflecting its cosmogenic origin and atmospheric transport sensitivity. In contrast, K-40 levels were more stable and strongly linked to geological characteristics such as granite distribution and altitude, with weaker meteorological dependence. Spatial analyses revealed distinct regional signatures, with elevated Be-7 in spring and K-40 increasing toward winter. Seasonal and geographic trends were further explained by lithological context and precipitation patterns. These findings highlight the contrasting environmental drivers of cosmogenic and terrestrial radionuclides, and support the importance of integrating climatic and geological variables in environmental radioactivity assessment. The approach presented here provides a transferable framework for interpreting radionuclide variability in other regions with complex atmospheric or lithological conditions.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107725"},"PeriodicalIF":1.9,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254314","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":"Assessment of radiation contamination of villages in northeastern Kazakhstan not covered by exposure rate measurements after atmospheric nuclear weapons tests conducted at the Semipalatinsk nuclear test site","authors":"Vladimir Drozdovitch ,&nbsp;Alexandra Lipikhina ,&nbsp;Kazbek Apsalikov ,&nbsp;Yulia Brait ,&nbsp;Alik Tokanov ,&nbsp;Gani Yessilkanov ,&nbsp;Rafail Rosenson ,&nbsp;Evgenia Ostroumova","doi":"10.1016/j.jenvrad.2025.107731","DOIUrl":"10.1016/j.jenvrad.2025.107731","url":null,"abstract":"<div><div>This paper presents the results of the first comprehensive assessment of radiation contamination of villages in Kazakhstan not covered by exposure rate measurements after atmospheric nuclear weapons tests conducted at the Semipalatinsk nuclear test site in 1949–1962. This was necessary to estimate radiation thyroid doses in 3183 individuals included in a cohort study of the prevalence of thyroid nodules detected by ultrasound, who lived during the testing period in 111 settlements where radiation measurements were not done. The values of exposure rate in these settlements were assessed using developed approaches to reconstruct the exposure rate along and across the fallout trace based on exposure rate measurements made at neighboring settlements after the same test. A total of 66 locations with measured exposure rates were available for the study. The validity of the approaches was tested using 24 pairs of exposure rates measured in villages located along the fallout trace at similar distances from the trace axis as well as by comparing with literature data. The results of this study are used to reconstruct thyroid doses in individuals who were exposed as children and young adults to fallout from atmospheric nuclear weapons tests conducted at the Semipalatinsk nuclear test site between 1949 and 1962.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"288 ","pages":"Article 107731"},"PeriodicalIF":1.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242173","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":"Comparison of 90Sr/137Cs activity ratios in the soil of fallout plumes from aboveground nuclear and thermonuclear tests at the Semipalatinsk Test Site","authors":"Yu V. Baklanova ,&nbsp;A.M. Kabdyrakova ,&nbsp;A.O. Aidarkhanov ,&nbsp;P. Ye Krivitskiy ,&nbsp;A. Ye Kunduzbayeva ,&nbsp;М.Т. Abisheva ,&nbsp;S.Ye Salmenbayev ,&nbsp;N.V. Larionova ,&nbsp;M. Gusyev","doi":"10.1016/j.jenvrad.2025.107726","DOIUrl":"10.1016/j.jenvrad.2025.107726","url":null,"abstract":"<div><div>Nuclear weapons testing leaves behind radioactive contamination as a long-lasting legacy and public health hazard at the Semipalatinsk Test Site (STS) and the ⁹⁰Sr and ¹³⁷Cs radionuclides are fission products with relatively high bioavailability due to the similarity of strontium to calcium and cesium to potassium. This study investigated ⁹⁰Sr and ¹³⁷Cs activity concentrations and ⁹⁰Sr/¹³⁷Cs ratios in topsoil (0–5 cm) and soil particle-size fractions collected in the fallout plumes from the 38 kt aboveground nuclear test conducted on September 24, 1951 (the Southern plume) and the 400 kt first thermonuclear test on August 12, 1953 (the Southeastern plume) at the center of the Experimental Field test site of the STS. From our findings, activity levels of radioactive ¹³⁷Cs contamination were comparable in the two plumes, but the Southeastern plume had higher ⁹⁰Sr levels. The estimated ⁹⁰Sr/¹³⁷Cs ratios were between 0.4 and 1.7 for the Southern plume, while the ratios of thermonuclear test's plume ranged between 1.1 and 5.4, which are assumed to be due to the different types and yields of the nuclear charges. For the Southeastern plume, the values of the ⁹⁰Sr/¹³⁷Cs ratios in soil particle-size fractions reduce as the size of the fractions decreased from 1000 to 40 μm. High activity concentration ratios of up to 6.2 were observed for fractions ranging from 250 to 1000 μm. In the Southern plume, radionuclides were concentrated in the 250-100 μm fraction, without variability of the radionuclide ratios based on particle-size fractions. The maximum ⁹⁰Sr/¹³⁷Cs ratio for the Southern plume did not exceed 3, and was less than 1 for finer fractions. As a result, the distribution of radionuclides by particle-sized fractions of soils in combination with other precision diagnostic methods of radioactive particles can help to identify sources and nature of radioactive fallout and to assess the degree of transformation of radioactive fallout over time, as well as the long-term effects of radioactive contamination on various environmental components.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"287 ","pages":"Article 107726"},"PeriodicalIF":1.9,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144230769","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}