Search Results (183)

Islands have high ecological and tourism value; however, owing to their remoteness and limited accessibility, environmental radioactivity is often less systematically evaluated than in mainland regions. This study investigates the distribution, source partitioning, and radiological implications of multi-radionuclides (⁷Be, ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K) in surface soils of Zhoushan Island, a representative tourism-oriented island in the East China Sea. Activity concentrations of ⁷Be, ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K ranged from 3.4 to 585.5, below detection limit −5.7, 45–1490, 33.3–72.4, 32.3–58.9, 37.8–91.7, and 439.6–872.3 Bq/kg, respectively. Using multivariate statistics and geochemical interpretation, we classified radionuclides into three groups: (i) atmospheric deposition-driven nuclides (⁷Be, ²¹⁰Pb_ex), (ii) lithogenic background-controlled nuclides (²³⁸U−²²⁶Ra−²³²Th), and (iii) the alkali-metal-like behavior group (¹³⁷Cs−⁴⁰K). This shows that soil radionuclide patterns result from atmospheric inputs, geological inheritance, and land-use disturbance, rather than simple concentration variability. Spatial analysis revealed that agricultural disturbance enhances ¹³⁷Cs redistribution, low-lying terrains preferentially accumulate atmospheric fallout nuclides, and lithogenic radionuclides are higher in the northern island due to parent material and weathering. No significant ⁴⁰K enrichment was observed in cultivated soils, indicating limited fertilizer influence. Although radiological indices remain within international safety thresholds, several parameters exceed global background levels, indicating elevated natural radiation driven primarily by thorium-rich lithology. Importantly, we show that radiological risk assessments based solely on bulk activity may overestimate environmental significance without considering process controls. This study provides a process-informed radiological assessment for island systems, offering insights for environmental monitoring and risk evaluation in similar coastal and tourism-dominated regions. Full article

Mapping the spatial distribution of fallout radionuclides in soil is essential for environmental assessments and evaluating potential future radiological risks, while also supporting the interpretation of spatial variability relevant to their use as soil redistribution tracers. However, model performance depends on data characteristics and spatial context, which limits the possibility of defining a universally optimal interpolation method. This study aimed to model the spatial distribution of ¹³⁷Cs at the national scale in Serbia by systematically applying and comparing 33 interpolation techniques, classified as deterministic or stochastic. A total of 193 soil samples, collected in accordance with International Atomic Energy Agency guidelines, were analyzed for ¹³⁷Cs activity using gamma spectrometry. The performance of interpolation techniques was evaluated through leave-one-out cross-validation (LOOCV) and an appropriateness index (AI) for comparison. Among the tested techniques, Empirical Bayesian Kriging Regression Prediction (EBKRP), which incorporates a digital elevation model (DEM) as an additional explanatory variable, achieved the best performance (AI = 0.8548). The resulting map of ¹³⁷Cs activity reveals a pronounced spatial gradient, with values ranging from below 22 Bq/kg to approximately 148 Bq/kg, reflecting the combined effects of initial ¹³⁷Cs deposition following the Chernobyl accident and subsequent long-term soil redistribution. Higher activities are restricted to the hilly and mountainous regions of western, eastern, and southeastern Serbia. Interpolation uncertainty increases in regions with elevated ¹³⁷Cs activities and should be accounted for in spatial interpretation. Full article

This study presents the radiological characterization of 15 solid radioactive waste samples originating from the BN-350 sodium-cooled fast reactor (Kazakhstan) during its decommissioning phase. The studied materials include components of ventilation and wastewater treatment systems, pipeline elements and various operational tools. The objective of the study was to determine the activity levels of the samples and to assess appropriate pathways for their subsequent management and processing. The results indicate that all studied materials fall within the category of low-level radioactive waste. Gamma spectrometric analysis shows that Cs-137 is the dominant and only identified gamma-emitting radionuclide contributing to the activity of the studied samples. Full article

Anthropogenic pollution may impose additional pressure on European populations of large protected carnivores due to the systemic toxicity of contaminants such as cadmium, lead, and radiocaesium (¹³⁷Cs). Our aim was to carry out ¹³⁷Cs, radiopotassium (⁴⁰K), and stable element distribution analysis through seven tissues of grey wolves (Canis lupus) from temperate forests of Croatia using ultra-low background gamma-ray spectrometry and ICPMS, respectively. In addition, radiolead (²¹⁰Pb) massic activity was quantified in femoral bone. The massic activity of ¹³⁷Cs in the heart, kidney, liver, spleen, lungs, and femoral bone (in decreasing order) ranged from 9–61% relative to muscle and showed strong inter-tissue correlations. However, correlations between radionuclides and their stable analogues in wolf tissues indicated considerable uncertainty in the use of stable element data for radiological risk assessment. In addition, concentration ratios (CR_{whole organism-soil}) derived from stable element data should be applied with caution when radionuclide data are lacking. Overall, radionuclide activities and element levels not subject to homeostatic regulation in grey wolves were comparable to or lower than those reported for other populations, particularly those from sub-Arctic regions. Despite being apex terrestrial predators, wolves inhabiting temperate ecosystems do not currently appear to be at risk of adverse health effects from exposure to the most relevant inorganic anthropogenic pollutants. Full article

Peloids are natural materials widely used in balneotherapy and dermatological treatments because of their physicochemical and mineralogical properties. Despite Serbia’s long tradition of spa-based pelotherapy, comprehensive data on the chemical and radiological characteristics of local peloids remain limited. In this study, peloid samples from 13 spa locations across four regions of Serbia were systematically investigated. The aim was to determine their physicochemical properties, elemental composition, and natural radioactivity, to assess their suitability and safety for therapeutic use. The analyzed samples exhibited pronounced variability in pH (6.59–9.52), electrical conductivity (77.5–6610 μS/cm), salinity (below detection limit to 4%), and total dissolved solids, reflecting diverse geological and hydrochemical properties. Inductively coupled plasma optical emission spectrometry revealed site-specific variations in macro- and microelements, influenced primarily by local lithology and sedimentary environments, with limited indications of anthropogenic inputs. Gamma spectrometric analysis showed that the activity concentrations of naturally occurring radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K, ²³⁸U, ²³⁵U, ²¹⁰Pb) were within ranges commonly reported for therapeutic muds worldwide, while anthropogenic ¹³⁷Cs was generally low. Radiological hazard indices were below internationally recommended safety limits. A preliminary screening of dermal exposure to potentially toxic elements indicated no significant noncarcinogenic risk (HI < 1) and acceptable carcinogenic risk (TCR) levels. Overall, this study provides a comprehensive chemical and radiological baseline for Serbian peloids, supporting their safe use in controlled therapeutic and wellness applications and highlighting the importance of site-specific characterization for quality assessment. Full article

Large amounts of radionuclides and microplastics (MPs) have been released and will continue to be discharge into the environment. They will exist and interact in the aquatic environment over extended periods. However, the toxicological risks associated with their co-exposure remain poorly understood. In this study, the zebrafish (Danio rerio) embryos were exposed to ¹³⁷Cs (6.8 × 10⁴ Bq/L) in combination with 9.9 μm polystyrene MPs (PS-MPs, 10, 100 μg/L) for 7 days. Early developmental growth was significantly influenced in the ¹³⁷Cs-exposed groups. This was evidenced by delayed hatching, increased swimming total distance, and anxiety behavior (increasing swimming distance in the inner circle). Furthermore, transcriptomic analysis demonstrated that a higher number of differentially expressed genes were found in the ¹³⁷Cs group compared to other exposure groups. In ¹³⁷Cs groups, KEGG enrichment analysis highlighted significant disruptions in lipid metabolism pathways. ¹³⁷Cs can influence its neuro-related genes by inducing lipid metabolism toxicity, providing a mechanistic explanation for the observed locomotory abnormalities in larvae. Interestingly, during the early stage of development, MPs appeared to reduce the internal irradiation dose and toxic effect by absorbing the ¹³⁷Cs. Overall, this study enhances our understanding of the ecological risks posed by combined exposure to ¹³⁷Cs and MPs. Full article

In rural areas affected by Chernobyl, accelerated erosion has become a major source of particulate ¹³⁷Cs in sediment load. The long-term dynamics of the activity concentration in eroded soil material transported from individual slope catchments can be better understood by exploring the ¹³⁷Cs depth distribution in sediments deposited near cultivated fields. This study focuses on three cultivated slope catchments located in the Chernobyl-affected area of Central Russia. A depth incremental campaign was conducted within zones of sediment accumulation in 2022–2025. The behavior of radiocaesium associated with particles after the Chernobyl accident was controlled by the prompt implementation of remediation measures. Shortly after the accident, the values decreased by more than two times. The radionuclide flux then began to depend on soil erosion processes. Gradually, the thickness of the upper soil that had been eroded became large enough to allow soil material from deeper layers to be involved during ordinary plowing and led to a subsequent decrease in the ¹³⁷Cs activity concentration. Given the decreasing snowmelt runoff and lack of increase in high-intensity rainfall in the 21st century, the activity concentration of ¹³⁷Cs in slope runoff has remained quite stable. This phenomenon requires consideration of whether a physically based model for the transport of particulate radionuclides should be developed. Full article

This study employed a metakaolin-based geopolymer (GP) to solidify potassium copper hexacyanoferrate after its saturation with adsorbed Cs⁺. The experiment was designed using response surface methodology (RSM) in the Design–Expert 13 software, targeting the compressive strength and cumulative leaching fraction of the solidified form. A regression model was developed to achieve the multi-objective optimization of the comprehensive performance of the GP solidified product. Regression analysis identified the optimal mix proportion as Na₂O/Al₂O₃ = 0.84, SiO₂/Al₂O₃ = 2.8, and H₂O/Na₂O = 10.23. Under these conditions, the experimentally measured compressive strength was 23.41 MPa. The 42-day cumulative leaching fractions at 25 °C and 40 °C were 7.906 × 10⁻⁴ cm and 1.5923 × 10⁻³ cm, respectively, both significantly below the national standard threshold (Standard Code GB7023-2011) of 2.6 × 10⁻¹ cm. The percentage error remained within 10%, indicating strong agreement with predicted values. These results suggest that metakaolin-based GP exhibits promising potential for the immobilization of radionuclides. Full article

Wood ash from biomass power plants and coarse, low-grade sheep wool from farming are underutilized biowastes that are often landfilled. Their valorization could reduce waste and emissions, decrease reliance on virgin materials, and support the circular economy and European Green Deal targets. However, both materials may contain naturally occurring radionuclides, primarily ⁴⁰K, as well as trace uranium and thorium isotopes, with higher concentrations typically found in wood ash due to combustion processes. Assessing their activity concentrations and bioavailability is therefore essential to ensure regulatory compliance and protect public health. This study quantified radionuclide levels in wood ash and sheep wool samples collected in Croatia and evaluated their suitability for agricultural applications. Natural radionuclides (⁴⁰K, ²³²Th, ²³⁸U, ²¹⁴Pb, ²¹⁴Bi, ²²⁶Ra, ²¹⁰Pb, ²¹⁰Po) and ¹³⁷Cs were determined using high-resolution gamma-ray and alpha spectrometry. The influence of different factors on radionuclide content was discussed, and transfer factors within the soil–hay–wool pathway were calculated to assess bioavailability. Measured activity concentrations were consistently low, and transfer factors indicated minimal radionuclide mobility. The results support the safe agricultural reuse of these materials and provide baseline data for radiological safety assessments in sustainable waste management practices. Full article

This study examines the hydro-sedimentological–radioecological controls governing the distribution of natural (K-40, Ra-226, Th-232) and anthropogenic (Cs-137) radionuclides in surface sediments of the western Black Sea shelf. Activity concentrations were determined by high-resolution gamma spectrometry, and radiological indices—including radium equivalent activity (Ra_eq), external hazard index (H_ex), and annual effective dose (AED)—were calculated to evaluate environmental safety. All indices remained well below internationally accepted thresholds, confirming the absence of radiological hazard in both coastal and offshore settings. Strong correlations between Ra-226 and Th-232 indicate dominant lithogenic control of natural radionuclides, whereas Cs-137 exhibits geochemical decoupling consistent with its behavior. A significant relationship between the fine-grained sediment fraction (<63 µm) and Cs-137 activity highlights the grain size effect, with offshore depositional zones acting as sediment-focusing areas where Cs-137 and excess Pb-210 co-accumulate under low-energy hydrodynamic conditions. Despite localized offshore enrichment, dose contribution analysis shows that natural radionuclides dominate the absorbed-dose budget, while Cs-137 contributes only marginally. Spatial predictive modeling using Artificial Neural Networks, validated under a Spatial Leave-One-Group-Out framework, yielded moderate generalization capacity (R² = 0.61 for Ra-226; R² = 0.41 for Cs-137), reflecting smoother spatial gradients of lithogenic radionuclides than heterogeneous radiocesium deposition. Furthermore, Machine Learning algorithms provided significant analytical value: a Random Forest (RF) model successfully classified environments (nearshore/shelf/depositional basin) based on distinct radionuclide signatures. At the same time, an optimized Artificial Neural Network (ANN-GA) enabled the nonlinear reconstruction of radiometric–granulometric patterns to identify local anomalies. The results show that radionuclide distributions are primarily structured by sediment provenance, grain size sorting, and hydrodynamic energy gradients rather than ongoing anthropogenic inputs. Full article

Current internal dose assessments in nuclear emergencies rely on static, upright voxel phantoms, often neglecting realistic human postures and physiological factors—such as breathing rates specific to emergency scenarios—that influence radionuclide intake and biokinetics. We present a voxel deformation method based on an improved as-rigid-as-possible (ARAP) algorithm incorporating a novel smoothing term to generate anatomically consistent stooping and swivelling models. Coupled with Geant4 Monte Carlo simulations using the full decay spectra of radionuclides relevant to simulated nuclear accident scenarios (i.e., ¹³¹I and ¹³⁷Cs), and incorporating scenario-specific respiratory parameters into activity calculations, our results demonstrate that body posture significantly influences internal dose distributions: for ¹³⁷Cs, the specific absorbed fraction (SAF) of the liver increases by up to 24.9% in the stooping posture, while swivelling induces variations of up to 15.1%. In contrast, dose metrics for ¹³¹I show minimal sensitivity to posture (<5%). These findings highlight the importance of incorporating realistic postures and context-aware physiological parameters into emergency dosimetry. Our method enables behaviorally realistic internal dose reconstruction and provides a robust foundation for integrating human motion and respiratory data into rapid triage and risk assessment protocols. Full article

This study focuses on the synthesis and characterization of buckwheat husk-derived activated carbon, chemically activated with potassium hydroxide (KOH) and subsequently modified with urea and Prussian Blue (PB). The obtained carbons were evaluated in terms of particle-size distribution, surface morphology, structural features, and electrokinetic properties using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and electrophoresis, as well as N₂ adsorption–desorption (BET surface area and porosity analysis). The results confirmed that both pyrolysis conditions and the type of modifier significantly affect the physicochemical properties of the activated carbon and its behavior in electrolyte solutions. Colloidal stability and particle size were strongly dependent on pH and the type of anions present in solution, with sodium nitrate (NaNO₃) systems showing higher stability than sodium chloride (NaCl). Modification with KOH and urea imparted a more basic surface character, whereas PB introduced more acidic properties. All samples exhibited predominantly negative surface charges and mesoporous structures, which are favorable for adsorption processes and enhance affinity for heavy-metal cations. Among the tested materials, BH-KOH-Fe (Fe-modified KOH-activated carbon) showed the most favorable performance for the targeted application, while BH-KOH (KOH-activated buckwheat husk-derived carbon) exhibited high surface area and good colloidal stability. The prepared materials show promising applicability for water purification, including the removal of organic pollutants and radionuclides (e.g., ¹³⁷Cs and ⁹⁰Sr), as well as metal cations (K⁺, Na⁺, and Li⁺). Full article

Saltmarshes have emerged as important sinks for microplastic (MP) pollution, yet little is known about the long-term accumulation and retention mechanisms of MPs in these environments. This study presents the first chronological record of MPs in Mediterranean saltmarsh sediments, using sediment cores dated via a combination of AMS radiocarbon (¹⁴C) and radionuclide (²¹⁰Pb, ¹³⁷Cs, ²⁴¹Am) from two saltmarshes located on the Adriatic Sea coast of Croatia (Blace and Jadrtovac). MPs were extracted and analysed across core depths and assessed in relation to geochemical parameters (organic matter (OM), carbonates, organic carbon (C-org), total nitrogen (TN), phosphorus (P) forms’ content, and grain size distribution). Results show that MPs first appear in sediments dated to 1950 in Jadrtovac and post-1960 in Blace, with concentrations increasing markedly in more recent surface layers. Jadrtovac exhibited higher MP concentrations (up to 0.5 MPs g⁻¹), dominated by fibres (86%) associated with urban and maritime sources, while Blace showed lower concentrations, dominated by fragments (60%), likely from localised sources such as agriculture or single-use packaging. Polymer analysis confirmed contrasting source profiles, with rayon and cellophane dominating in Jadrtovac, and polypropylene and olefin in Blace. MPs positively correlated with OM, C-org, P, TN and sand content, and negatively with clay and carbonate content. Principal component analysis (PCA) confirmed that MPs were associated with organic-rich, sandy sediments. These findings demonstrate that OM composition and sediment texture significantly influence MP retention and highlight the role of saltmarshes as long-term archives of plastic pollution in low-energy coastal settings. Full article

Castration-resistant prostate cancer presents radiotherapeutic challenges, especially in optimizing the cytosolic internalization of therapeutic radiopharmaceuticals. This research aimed to design and evaluate in vitro, a new dimeric radiopharmaceutical, [¹⁷⁷Lu]Lu–iPSMA–iGRP78, which combines PSMA and GRP78 inhibitors in a heterodimeric radioligand to improve the radionuclide internalization and cytotoxicity efficacy. Molecular docking showed that the dimer iPSMA–iGRP78 presents a higher affinity for GRP78 (CNN-docking score: −14.0 kcal·mol⁻¹, pKi: 10) and for PSMA (CNN-docking score: −17.0 kcal·mol⁻¹, pKi: 11.5) compared to the monomers iGRP78 (CNN-docking score: −11.0 kcal·mol⁻¹, pKi: 9.4) and iPSMA (CNN-docking score: −13.9 kcal·mol⁻¹, pKi: 10.2). The saturation binding assay using LNCaP cells (PSMA+, CS-GRP78+) showed an affinity (K_d) of 1.883 nM for [¹⁷⁷Lu]Lu–iPSMA–iGRP78 and 2.245 nM for [¹⁷⁷Lu]Lu–iPSMA. The dimeric radiopharmaceutical achieved 10.44 ± 2.43% cytosolic internalization and 4.81 ± 0.94% nuclear internalization, while the [¹⁷⁷Lu]Lu–iPSMA monomer showed 6.45 ± 0.60% cytosolic internalization and no uptake in the cell nucleus. In PC3 cells (PSMA–, CS-GRP78–), [¹⁷⁷Lu]Lu–iPSMA–iGRP78 uptake was negligible, demonstrating specificity. Treatment with the dimeric radiopharmaceutical reduced cell viability (69.93 ± 4.85% of dead cells) significantly more than [¹⁷⁷Lu]Lu–iPSMA (38.63 ± 6.13% of dead cells). In conclusion, conjugation of a GRP78 inhibitor to [¹⁷⁷Lu]Lu–iPSMA improves the radionuclide internalization and cytotoxicity in prostate cancer cells, suggesting that the bispecific radiopharmaceutical is a promising strategy in prostate cancer treatment. Full article

Ion exchange resins are commonly utilized for treating liquid radioactive waste within nuclear power plants; however, the disposal of these waste resins presents a new challenge. In this study, magnesium silicate hydrate cement (MSHC) was used to immobilize the waste resin, and the immobilization effectiveness of the MSHC-solidified body were assessed by mechanical properties, durability, and leaching performance. Hydration heat, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), and mercury intrusion porosimetry (MIP) were used to study the hydration process of the MSHC-solidified body containing Cs⁺, Sr²⁺, and Cs⁺/Sr²⁺ waste resins. The results demonstrated that the presence of waste resins slightly delayed the hydration reaction process of MSHC and reduced the polymerization degree of the M-S-H gel, and the composition of the hydration products were not changed. The immobilization mechanism for radionuclide ions in resin included both mechanical encapsulation and surface adsorption, and the leaching of Cs⁺ and Sr²⁺ from MSHC-solidified body followed the FRDIM. When the content of the waste resin was 25%, the MSHC-solidified body exhibited satisfactory compressive strength, freeze-thaw resistance, soaking resistance, and impact resistance. These results strongly indicated that MSHC possessed the ability to effectively immobilize ion exchange resins. Full article