Journal of environmental radioactivity最新文献

{"title":"Evaluation of radon progeny mitigation techniques (HEPA filtration, ionization, electrostatic deposition) and their potential use in caves","authors":"J.E. Martínez,&nbsp;B. Juste,&nbsp;G. Verdú","doi":"10.1016/j.jenvrad.2026.108063","DOIUrl":"10.1016/j.jenvrad.2026.108063","url":null,"abstract":"<div><div>Radon and its short-lived progeny are recognized as significant contributors to the radiological dose received indoors and are associated with increased lung cancer risk. This study evaluates the effectiveness of various air purification technologies—including HEPA filtration, ionization, electrostatic deposition, and combined systems—in reducing airborne concentrations of radon progeny (PAEC, ²¹⁸Po, and ²¹⁴Po) in a controlled, non-ventilated environment. Measurements were carried out using active and passive detectors over multiple campaigns with and without air purifiers. Statistically significant reductions were observed for all purification methods tested, with the greatest decrease found for ²¹⁴Po and PAEC, and more moderate reductions for ²¹⁸Po. The combination of HEPA filtration and ionization proved most effective, achieving reductions exceeding 40% in PAEC. The results confirm that air purification systems, particularly those using ionization and electrostatic principles, can play a crucial role in mitigating radon progeny exposure in enclosed spaces. These findings support the practical implementation of air purification strategies in high-risk environments such as underground workplaces, shelters, and laboratories.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"297 ","pages":"Article 108063"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148156762","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":"Modelling marine radioactive spills in the context of the current war in the Middle East","authors":"Raúl Periáñez","doi":"10.1016/j.jenvrad.2026.108054","DOIUrl":"10.1016/j.jenvrad.2026.108054","url":null,"abstract":"<div><div>In the current geopolitical context, the possibility of a radiological incident resulting from an attack on nuclear infrastructure or a nuclear-powered naval vessel in active maritime theaters of conflict cannot be entirely dismissed. This paper presents a suite of Lagrangian radionuclide transport models covering the marine domains most directly affected by the present Middle East war: the Red Sea, the Persian Gulf, and the Northern Indian Ocean. The models incorporate advection by currents derived from a global ocean model, three-dimensional turbulent mixing, radioactive decay, and dynamic water-sediment interactions described through reversible kinetic adsorption-release reactions. Tidal transport, which is particularly relevant in semi-enclosed basins such as the Persian Gulf and the Red Sea, can be optionally included via tidal currents obtained from a previously validated tidal propagation model. The modelling framework is consistent with the recommendations of the International Atomic Energy Agency MODARIA programme regarding the availability of marine radionuclide transport tools for rapid deployment in nuclear emergency scenarios. Some illustrative simulations of a hypothetical release of ¹³⁷Cs from a nuclear facility located in the southern Persian Gulf and from a ship in the entrance of the Gulf of Oman are presented. The models are ready to be operationally applied should a radiological emergency arise in any of these regions.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"297 ","pages":"Article 108054"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148042678","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":"Age-dependent bioaccumulation of radionuclides in pond-raised Heteroclarias catfish in Ondo State, Nigeria","authors":"Olajire Joshua Olajide,&nbsp;Oladele Samuel Ajayi","doi":"10.1016/j.jenvrad.2026.108051","DOIUrl":"10.1016/j.jenvrad.2026.108051","url":null,"abstract":"<div><div>This research investigated age-dependent distribution and bioaccumulation of natural radionuclides in pond-raised <em>Heteroclarias</em> catfish from Ondo State, Nigeria, with emphasis on sediment-water-biota interactions. Activity concentrations (dry mass) of ⁴⁰K, ²²⁶Ra, and ²³²Th were determined in 3-month-old and 14-month-old <em>Heteroclarias</em> catfish, as well as in pond water and sediments using gamma spectrometry. Radionuclide transfer factors and ingestion-related effective doses were also evaluated. Across all sampled matrices, ⁴⁰K was the dominant radionuclide. Mean ⁴⁰K activity concentrations in fish increased significantly from 181.3 ± 3 Bq kg⁻¹ in 3-month-old fish to 280 ± 4 Bq kg⁻¹ in 14-month-old fish (p &lt; 0.05), indicating cumulative uptake with age. In contrast, ²²⁶Ra and ²³²Th showed higher activity concentrations in pond sediments, confirming sediments as the main reservoir of these radionuclides. Transfer factor analysis showed higher water-to-fish transfer of ⁴⁰K and ²²⁶Ra in older fish, whereas ²³²Th exhibited greater transfer in younger fish, suggesting sediment-associated uptake during early growth stages. Estimated annual effective dose equivalents ranged from 30 to 36 μSv y⁻¹, with excess lifetime cancer risk values below internationally recommended limits. Overall, the findings indicate no significant radiological risk associated with consumption of pond-raised <em>Heteroclarias</em> catfish and underscore the importance of age and sediment-mediated processes in freshwater radioecological assessments.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"297 ","pages":"Article 108051"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148054805","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":"Gamma emissions from NORM in building materials: A position paper on national transposition of the Euratom basic safety standard","authors":"M. Dodek ,&nbsp;R.E. Djabou ,&nbsp;C. Sainz ,&nbsp;I. Fuente ,&nbsp;L.L. Vintró ,&nbsp;O. Hanley ,&nbsp;J. Goggins ,&nbsp;M. Foley","doi":"10.1016/j.jenvrad.2026.108056","DOIUrl":"10.1016/j.jenvrad.2026.108056","url":null,"abstract":"<div><div>This position paper examines how the Euratom Basic Safety Standards (EU-BSS), Council Directive 2013/59/Euratom) on gamma radiation from building materials have been transposed into national regulation across selected EU Member States. It focuses on Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Ireland, Italy, Poland, Portugal, Netherlands, Spain, and Sweden. Drawing on national legislation, technical guidance and direct correspondence with regulators and researchers, the paper compares who is responsible for characterising Naturally Occurring Radioactive Material (NORM) in building materials, and how compliance with the 1 mSv/year reference level is demonstrated. Across the countries studied, regulation is broadly convergent with the Gamma Index being widely used as a screening tool. Responsibility for measurements generally lies with manufacturers or suppliers using accredited laboratories with <strong>r</strong>egulatory attention primarily focused on natural igneous and pozzolanic stones, alum-shale–related products, and construction materials containing industrial residues such as fly ash, phosphogypsum, slags and red mud. At the same time, there are notable differences in the existence of long-term national datasets, the degree of integration with construction-product approval systems, and whether NORM above exemption levels is treated as radioactive waste or managed under a more flexible “existing exposure” regime. The paper provides a current snapshot of this evolving European regulatory landscape and is intended to inform the further development of proportionate NORM regulation and monitoring strategies for building materials and recycled building materials in Europe. Its added value lies in bringing dispersed national sources into a single comparative framework and in identifying recurring implementation models, practical divergences and emerging issues for recycled and secondary materials.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"297 ","pages":"Article 108056"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148150080","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":"Unexpected detection of the 123Xe/123I pair and its impact on radioxenon measurements in the SPALAX-NG system","authors":"Anthony Der Mesrobian-Kabakian ,&nbsp;Anne de Vismes-Ott ,&nbsp;Sylvia Generoso ,&nbsp;Philippe Gross ,&nbsp;Valérie Lourenço ,&nbsp;Mireille Morin ,&nbsp;Sylvain Topin","doi":"10.1016/j.jenvrad.2026.108053","DOIUrl":"10.1016/j.jenvrad.2026.108053","url":null,"abstract":"<div><div>This study reports the first documented detection of ¹²³Xe in the context of the CTBTO's International Monitoring System (IMS), in samples collected by the SPALAX-NG system (CEA/DIF, France). ¹²³Xe is a short-lived radioisotope (T_1/2 = 2.05 h) produced during medical ¹²³I synthesis; atmospheric releases from medical facilities can lead to ¹²³Xe capture by nearby IMS stations, potentially causing false ^131mXe detections due to spectral overlaps in regions of interest (ROIs). Using high-resolution gamma and coincidence spectroscopy, we confirmed the presence of ¹²³Xe and its decay product, ¹²³I, in collected air samples.</div><div>To mitigate interference, we developed an analytical adaptation for SPALAX-NG that identifies ¹²³Xe via its 149 keV gamma peak and adjusts ROIs 5 and 6, with minimal efficiency loss (≤2.8%). This solution ensures accurate discrimination between ¹²³Xe and CTBT-relevant isotopes. Our findings demonstrate the need to account for non-CTBT radioxenon isotopes in IMS analyses, particularly near medical isotope production sites, and advocate for high-resolution detection systems to improve monitoring reliability under the CTBT.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"297 ","pages":"Article 108053"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148031285","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":"Temporal and spatial variation in 137Cs concentrations in wild boar (Sus scrofa) from Sweden","authors":"Mykhailo Vinichuk ,&nbsp;Klas Rosén ,&nbsp;Pål Andersson ,&nbsp;Julia Kyaschenko ,&nbsp;Robert N. Weimer","doi":"10.1016/j.jenvrad.2026.108006","DOIUrl":"10.1016/j.jenvrad.2026.108006","url":null,"abstract":"<div><div>This study investigates temporal and spatial variation in ¹³⁷Cs activity concentrations in Swedish wild boar between 2011 and 2024 to assess long-term ecological impacts of radiocaesium of anthropogenic origin. Data from a total of 5844 meat samples collected across 39 municipalities in six counties were analysed. Average ground deposition of ¹³⁷Cs in these municipalities in 1986 ranged from 1.84 to 51.55 kBq m<strong>⁻</strong>². The average ¹³⁷Cs concentration in wild boar meat was 1679 Bq kg⁻¹, with 27.5% of samples exceeding the sales limit of 1500 Bq kg⁻¹.</div><div>Seasonal variation in ¹³⁷Cs activity concentrations in wild boar meat was evident, with levels peaking in winter and early spring and declining nearly fivefold in late summer and early autumn, across all locations. On average, younger boars (≤1 year) exhibited 25% higher concentrations than older individuals, with the greatest differences observed in winter and no differences in autumn. No sex-specific differences in concentrations were detected. A weak but statistically significant correlation was observed between meat radioactivity and average ground deposition across all counties, with a slightly weaker correlation in Gävleborg and Uppsala. Overall, ¹³⁷Cs deposition remained the primary factor explaining the observed levels of meat contamination. A twofold increase in ¹³⁷Cs deposition resulted in an almost proportional increase in ¹³⁷Cs activity concentrations in wild boar meat, whereas the ¹³⁷Cs transfer factor (<em>T</em>_ag) remained largely unchanged. The geometric mean <em>T</em>_ag for wild boar was 0.052 m² kg⁻¹, while the effective half-life (<em>T</em>_eff) of ¹³⁷Cs varied widely among municipalities (2–3 to &gt;30 years); no <em>T</em>_eff could be estimated for the study area as a whole due to the absence of a consistent decline in ¹³⁷Cs activity concentrations.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"296 ","pages":"Article 108006"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147773046","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":"Feasibility study of tRAYcy-based efficiency calibration and transfer methods for HPGe gamma-ray spectrometry","authors":"Jaehyeon Seo ,&nbsp;Hyemi Cha ,&nbsp;Younghak Kim,&nbsp;Chang-Jong Kim,&nbsp;Jong-Myoung Lim,&nbsp;Mee Jang","doi":"10.1016/j.jenvrad.2026.108017","DOIUrl":"10.1016/j.jenvrad.2026.108017","url":null,"abstract":"<div><div>This study evaluated the feasibility of using the Monte Carlo-based tRAYcy software for efficiency calibration and efficiency transfer in high-purity germanium (HPGe) gamma-ray spectrometry. Detection efficiencies were simulated employing both tRAYcy and MCNP6 for two Marinelli beaker geometries, 450 and 1000 mL, and were compared with experimental measurements obtained from certified multi-nuclide reference sources. Efficiencies simulated with tRAYcy showed good agreement with those generated using MCNP6, with average absolute relative differences of 5.3% and 7.3% for the 450 mL and 1000 mL geometries, respectively. Detector-parameter optimization within tRAYcy further improved agreement with experimental data, reducing the average absolute relative differences from initial values of approximately 12% to 5.2% and 5.7 % for the 450 mL and 1000 mL geometries, respectively. The efficiency transfer method estimated the efficiency of a target geometry by scaling an experimentally calibrated reference efficiency using the ratio of simulated efficiencies between two geometries. In this study, the 450 mL geometry served as the reference for deriving the 1000 mL efficiency. The transferred efficiencies obtained with tRAYcy agreed with direct experimental measurements, with an average absolute relative differences of 0.80%. Validation using proficiency test samples showed that the activity concentrations derived using the tRAYcy-based efficiency transfer agreed with the certified reference values within approximately 6.5%, except for ¹⁵²Eu. A zeta-score (ζ) evaluation showed acceptable agreement (|ζ| ≤ 2) for most radionuclides, whereas ¹⁵²Eu exhibited values marginally exceeding 2. These results indicate that tRAYcy is a practical tool for routine efficiency calibration and transfer in HPGe gamma-ray spectrometry.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"296 ","pages":"Article 108017"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147799177","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":"Interfacial processes and biogeochemical cycling of plutonium in environmental media: Sources, transformation, and impacts","authors":"Chun Zhang ,&nbsp;Xiang Zhou ,&nbsp;Hao Sun ,&nbsp;Zengyan Li ,&nbsp;Yu Wang ,&nbsp;Jia Zhan ,&nbsp;Weixian Wang ,&nbsp;Hui Xu","doi":"10.1016/j.jenvrad.2026.108014","DOIUrl":"10.1016/j.jenvrad.2026.108014","url":null,"abstract":"<div><div>Plutonium (Pu), an anthropogenic actinide with extreme radiotoxicity and chemotoxicity, derives mainly from nuclear weapons testing, accidents, and legacy waste disposal. Its environmental mobility and long-term fate are controlled by coupled interfacial reactions and biogeochemical cycling in soils, sediments, and aquatic systems. This review integrates recent advances in Pu sources, speciation, and distribution, with emphasis on adsorption–desorption at mineral–water interfaces, redox transformations across Pu(III/IV/V/VI) states, and colloid/nanoparticle-facilitated transport. Critical controls (pH, redox potential (Eh), dissolved organic matter, Fe/Mn (hydr)oxides, and microbial activity) are systematically evaluated. Microbial redox cycling, biological uptake, and immobilization pathways are shown to profoundly influence Pu speciation and transfer across environmental compartments. A unified conceptual model is presented to link interfacial processes with biogeochemical cycling under varying geochemical and climatic conditions. Current remediation technologies are critically assessed, revealing limitations and emerging interface- and microbe-targeted strategies. This synthesis provides a mechanistic framework for enhanced predictive modeling, risk assessment, and sustainable management of Pu-contaminated sites worldwide.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"296 ","pages":"Article 108014"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147773020","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":"Plutonium isotopes in surface air at Chiba City, Japan from 2016 to 2023: occurrence of anomalous 238Pu","authors":"Soichiro Suzuki ,&nbsp;Goh Abe ,&nbsp;Wataru Nitta ,&nbsp;Keisuke Isogai ,&nbsp;Fumiya Ishihara ,&nbsp;Katsumi Hirose","doi":"10.1016/j.jenvrad.2026.108013","DOIUrl":"10.1016/j.jenvrad.2026.108013","url":null,"abstract":"<div><div>Since 2016, we have measured plutonium isotopes in surface air at Chiba City by using alpha spectrometry and ICP-MS, together with large volume sampling and radiochemical analysis to identify sources of plutonium in air aerosol samples and to assess their effects. The monthly ^239,240Pu activity concentrations ranged from ND to 22 nBq/m³, showing a clear seasonal variation with a maximum in the spring season. Most of the plutonium in surface air at Chiba City is governed by resuspension of global fallout-derived Pu due to dispersion of soil particles at local and regional scales, such as long-range transport of East Asian continental dust (yellow dust). The monthly activity concentrations of ²³⁸Pu varied from not detected (ND; detection limit &lt;0.087 nBq/m³) to 3.4 nBq/m³, apart from anomalous values observed in February and March 2023, which were less than 20% of the corresponding ^239,240Pu concentrations. In March 2023, a marked peak of ²³⁸Pu activity concentration (25 nBq/m³) occurred. In addition, ²³⁸Pu/^239,240Pu activity ratios in February and March 2023 increased to 0.95 ± 0.095 and 1.1 ± 0.05, respectively, which were obviously higher than the global fallout ratio (0.02). The ²³⁸Pu/^239,240Pu activity ratio increased due to nuclear facility accident, such as Chernobyl, in which an enhanced ²⁴⁰Pu/²³⁹Pu atom ratio occurred. The ²⁴⁰Pu/²³⁹Pu atom ratios in the corresponding months were 0.17 ± 0.021 and 0.17 ± 0.007, respectively, which are similar to that of the global fallout ratio (0.18). Therefore, it is difficult to explain that the anomalous ²³⁸Pu during those periods of this study was derived from domestic nuclear facilities including Fukushima Daiichi Nuclear Power Station and/or global fallout origins.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"296 ","pages":"Article 108013"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147799179","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":"Linking forest compartments to the long-term decline rates of 137Cs in stream fish: A contaminated headwater catchment in Fukushima","authors":"Yumiko Ishii ,&nbsp;Jaeick Jo ,&nbsp;Toshihiro Wada ,&nbsp;Tsutomu Kanasashi ,&nbsp;Kazuyoshi Takasaki ,&nbsp;Wataru Teramoto ,&nbsp;Yuto Funaki ,&nbsp;Ayame Inomata ,&nbsp;Shinya Shimamura ,&nbsp;Masaru Sakai ,&nbsp;Hiroshi Kurikami ,&nbsp;Seiji Hayashi","doi":"10.1016/j.jenvrad.2026.108009","DOIUrl":"10.1016/j.jenvrad.2026.108009","url":null,"abstract":"<div><div>Long-term monitoring after the Fukushima Daiichi accident have shown that ¹³⁷Cs concentrations in freshwater fish do not always decrease exponentially; they level off at relatively high values more than a decade after the fallout. In forested headwater streams, insectivorous salmonids are closely associated with forest-derived prey species. Because ¹³⁷Cs is redistributed among forest compartments and declines at different rates over time, the compartments and pathways that control long-term contamination in fish remain unclear. We quantified temporal changes in ¹³⁷Cs across forest–stream compartments, including masu salmon (<em>Oncorhynchus masou</em>) and white-spotted charr (<em>Salvelinus leucomaenis</em>), in two contaminated reaches of the Ota River, Fukushima, from 2018 to 2025 (7–14 years post-accident). Leaf, litter, periphyton, and dissolved ¹³⁷Cs generally declined, with effective half-lives of 2–7 years. In contrast, masu salmon showed no clear decline, whereas white-spotted charr decreased slowly, with a half-life of 7–13 years. Terrestrial insects showed no consistent decline, and exhibited highly variable ¹³⁷Cs concentrations among the feeding groups, reflecting uptake from heterogeneously contaminated forest compartments. Correlation network analysis indicated that masu salmon was more strongly coupled to terrestrial insects than to white-spotted charr, suggesting that terrestrial insects are a key pathway for continued exposure to forest-derived ¹³⁷Cs. These results indicate that ¹³⁷Cs stored in near-surface forest soils remains a persistent source for terrestrial fish prey. Our findings highlight the striking persistence of ¹³⁷Cs in masu salmon, raise concerns for fishery recovery, and suggest pathways sustaining this contamination. Clarification of these pathways will provide a basis for more accurate long-term predictions.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"296 ","pages":"Article 108009"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147799180","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}