Search Results (140)

Radon’s radioactive decay is the main natural source of small air ions near the ground. Its exhalation from soil is affected by meteorological factors, while aerosol pollution reduces air ion concentrations through ion-particle attachment. This study aimed to analyze correlations between radon, ions, and air pollution under varying conditions and to assess potential health impacts. Measurements were taken at two sites: in early autumn at a suburban part of Belgrade with relatively clean air, and in late autumn in central Belgrade under polluted conditions, with low temperatures and high humidity. Parameters measured included radon, small air ions, particle size distribution, PM mass concentration, temperature, humidity, and pressure. Results showed lower radon concentrations in late autumn due to high soil moisture and absence of nocturnal inversions. Radon and air ion concentrations exhibited a strong positive correlation for both polarities under suburban conditions, whereas measurements in the urban setting revealed a weak negative correlation, despite radon concentrations in soil gas being approximately equal at both sites. Small ion levels were also reduced, mainly due to suppressed radon exhalation and increased aerosol concentrations, especially ultrafine particles. A strong negative correlation (r < −0.5) was found between small air ion concentrations and particle number concentrations in the 20–300 nm range, while larger particles (300–1000 nm and >1 µm) showed weak or no correlation due to their lower and more stable concentrations. In contrast, early autumn measurements showed a diurnal cycle of radon, characterized by nighttime maxima and daytime minima, unlike the consistently low values observed in late autumn. Full article

The geological containment of high-level radioactive waste has become widely accepted among international organizations, and it has been adopted by many countries as part of their national nuclear waste disposal plan. The multi-barrier system, including the compacted bentonite blocks or pellets serving as human-made containment or buffer media, is the key component of high-level radioactive waste disposal, which contains a waste canister that isolates the nuclear waste from a human being geosphere for one million years. The bentonite clay surrounding the nuclear waste capsule is subjected to prolonged exposure to elevated temperatures because of the continuous decay of radioactivity. Long-term heating at high temperatures could change the buffers’ microstructural characteristics and physicochemical and hydromechanical properties, which can influence their self-sealing ability. This paper offers a comprehensive overview of the current understanding of thermal effects on bentonite-based buffer systems. The thermal impact on the microstructure, Atterberg limits, and swelling pressure of bentonite clay are intensely reviewed, and the findings are summarized. This review paper highlights new insights into the design of multi-layered containment approaches for high-level radioactive waste isolation. Full article

This work presents the results of a multi-technique comparative investigation aimed at assessing the mineralogical composition and radioactivity levels of two stone fragments from different areas of the archaeological site of Halaesa (Sicily, Italy). The analysis employed an integrated approach combining μ-energy-dispersive X-ray fluorescence (μ-EDXRF) spectroscopy, µ-Raman spectroscopy, X-Ray Diffraction (XRD), ion chromatography (IC), High-Purity Germanium (HPGe) gamma spectrometry, and E-PERM electret ion chamber methods. By examining the stone composition at both the elemental and molecular scales, with support from ion chromatography data, potential degradation patterns linked to post-depositional weathering and external decay agents were identified. Moreover, the specific activity of radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) and the ²²²Rn exhalation rates were measured, enabling the estimation of a set of radiological indices that assess potential health hazards associated with prolonged exposure to these lithic materials. The findings highlight how a multidisciplinary approach can foster the assessment of stone deterioration mechanisms, supporting the design of optimized conservation strategies aimed at preserving the archaeological heritage of Halaesa and ensuring the safety of both the public and onsite personnel. Full article

Radon is an inert gas produced by the radioactive decay of uranium-238, commonly found in the environment. Radon and its decay products are the main sources of human exposure to radiation from natural sources. When inhaled, radon’s alpha particles impact lung tissue, potentially causing lung cancer by damaging DNA and altering oxidative processes. This review article addresses the need for a deeper understanding of the genetic and molecular changes associated with radon-induced lung cancer, aiming to clarify key genetic mutations and protein markers linked to carcinogenesis. Particular attention in recent studies has been given to mutations in tumor suppressor genes (RASSF1, TP53), oncogenes (KRAS, EGFR), and changes in the expression levels of protein biomarkers associated with inflammation, stress, and apoptosis. Identifying these markers is critical for developing effective screening methods for radon-induced lung cancer, enabling timely identification of high-risk patients and supporting effective preventive strategies. Summarizing current genetic and protein biomarkers, this review highlights the importance of a comprehensive approach to studying radon-induced carcinogenesis. Understanding these molecular mechanisms could ultimately improve early diagnostic methods and enhance therapy for cancers associated with radon exposure. Full article

Background/Objectives: The kinase p38α, a member of the mitogen-activated protein kinase (MAPK) family, is activated by external stimuli and plays a crucial role in inflammation, tumor growth, and metabolic disorders. In particular, p38α is involved in thermogenesis and the metabolism of glucose in brown adipose tissue (BAT), and it contributes to the suppression of obesity and diabetes. The noninvasive imaging of activated p38α could help elucidate diverse pathological processes, including metabolic and inflammatory conditions. This study aimed to develop and evaluate a novel fluorine-18-labeled positron emission tomography (PET) probe for imaging activated p38α in vivo. Methods: We designed 6-(4-[¹⁸F]fluoro-2-fluorophenoxy)-8-methyl-2-(tetrahydro-2H-pyran-4-ylamino)-pyrido[2,3-d]pyrimidin-7(8H)-one ([¹⁸F]R1487) by replacing a fluorine atom in R1487, which is a highly selective p38α inhibitor, with ¹⁸F. A tributylstannyl precursor was reacted with [¹⁸F]KF in the presence of a copper catalyst to synthesize [¹⁸F]R1487. Biodistribution studies and PET/computed tomography (CT) were performed on normal mice to evaluate the in vivo potential of [¹⁸F]R1487. Results: [¹⁸F]R1487 was obtained with a decay-corrected radiochemical conversion of 30.6 ± 5.6% and a decay-corrected radiochemical yield of 6.9 ± 3.6% with a radiochemical purity of >99% after reversed-phase high-performance liquid chromatography purification. The biodistribution study demonstrated high and rapid radioactivity accumulation in BAT (16.3 ± 2.7 %ID/g at 5 min post-injection), with a consistently high BAT-to-blood ratio (>5 over 2 h post-injection). PET/CT imaging successfully visualized BAT with high contrast. Conclusions: These results suggest that [¹⁸F]R1487 is a promising PET probe for imaging activated p38α in vivo, which has potential applications for pathophysiological conditions such as inflammation, cancer, and metabolic disorders. Full article

Radioactive metal oxides are highly radioactive, hygroscopic spent fuel reprocessing products generally stored in container-sealed dry storage. During the storage process of metal oxides, a large amount of heat is generated due to radioactive decay, and helium is produced by α-decay, which leads to an increase in the temperature and pressure of the storage container. In order to ensure the safety of the radioactive metal oxides in the long-term storage process, computational fluid dynamics simulations are used to investigate the effects of storage conditions on the temperature and pressure of the container. Based on a large amount of simulated temperature data under different storage conditions, a power function is used to construct a mathematical model of ventilation speed, ventilation temperature, stack density, loading volume, heating power, water content, and cumulative helium mass versus metal oxide temperature to obtain a safe, reliable, and economical storage method. The results show that reducing the loading volume and increasing the density of metal oxides, increasing the ventilation speed, and lowering the ventilation temperature are beneficial to the heat transfer and cooling in the dry storage process; increasing the density of metal oxides and lowering the water content of metal oxides and increasing the ventilation temperature and speed are beneficial to avoid the high pressure inside the container. Based on the optimized storage conditions, the temperature peak in the storage process occurs near 25 years, and its temperature reaches 527.6 K. The mathematical model of storage temperature constructed in this study has high computational accuracy, and the maximum relative error of storage temperature is less than 1.80%. Full article

The ocean is a significant global reservoir of uranium (U) and thorium (Th). These elements can be incorporated into marine sediments through processes involving organic matter (OM), redox conditions, terrigenous inputs, and mineral interactions. Helium generated through the radioactive decay of U and Th within geological formations represents a critical potential resource. Marine black shales, which are rich in U and Th, are widespread in the Ediacaran Doushantuo Formation of the Upper Yangtze Platform, making them a key target for helium exploration. However, there is limited research on the mechanisms behind U and Th accumulation in these shales. This study focuses on shales from the Doushantuo Formation in Chongqing, China, aiming to explore the mechanisms of U and Th accumulation and assess the potential for helium generation, and argillaceous dolomites are included for comparative analysis. The results show that the average U and Th content in the black shales (17.58 and 9.78 ppm, respectively) is higher than that of argillaceous dolomites (3.52 and 2.75 ppm, respectively). Uranium mainly comes from authigenic precipitation and hydrothermal inputs, while thorium is primarily sourced from terrigenous and hydrothermal inputs. The semi-humid climate in the provenance area facilitated parent rock weathering, with atmospheric precipitation and river systems transporting U and Th to the ocean. However, excessive terrigenous input can dilute the U and Th content in the sediments. In the shales, uranium is primarily adsorbed and/or complexed by organic matter (OM), with the anoxic–euxinic sedimentary environment and high OM content (TOC = 0.06–34.58 wt.%, r = 0.95) promoting U accumulation. Thorium accumulation is largely controlled by adsorption onto clay minerals. The total amount of helium generated from the Doushantuo shales is estimated to be 7.20 × 10¹⁰ m³. Full article

Heavy metal pollution is a major environmental concern due to the high toxicity of heavy metals in humans. High natural background radiation areas (HNBRAs) contain high concentrations of the radioactive element ²³⁸U, which decays into ²⁰⁶Pb, in their soil, crops, and water. Concentrations of the heavy metals lead (Pb) and uranium (U) are, thus, correlated with HNBRAs. Mamuju in Indonesia is a recently studied HNBRA where high concentrations of Pb and U in the soil have been reported. The present study analyzes Mamuju residents’ exposure to Pb and U. Two zones in the study area were selected for comprehensive assessment. North Botteng was chosen to represent the HNBRA, and Topoyo was selected as the control zone, with 22 urine samples collected from each zone. The samples were analyzed using a quadrupole inductively coupled plasma mass spectrometer (ICP-MS). The average concentrations of Pb measured in the urine samples were 1.31 mg L⁻¹ and 0.77 mg L⁻¹ in North Botteng and Topoyo, respectively. These values are higher than the urine Pb reference value of 5 µg L⁻¹. The urine Pb concentrations in both studied zones were alarmingly high, which may have serious health effects on the population and should warrant action to reduce Pb exposure in this area. The committed effective dose from the ingestion of ²³⁸U in North Botteng was higher than in Topoyo, measuring 36.0 mSv and 8.9 mSv, respectively. The area most affected by the ingestion of ²³⁸U was the red bone marrow, followed by the bone surface. Full article

This article systematizes research data on the natural radioactivity of fossil coals and of ash and slag waste from coal power engineering in the context of radioecological safety. The relatively low energy efficiency of the operating thermal power plants in Kazakhstan has a significant impact on the environment. In addition to natural radioactive elements (U²³⁸ and its decay products, Th²³² and its decay products, and K⁴⁰), coal combustion waste also contains a significant amount of trace elements that have a negative impact on the atmosphere and the environment. In Kazakhstan, about 67% of electricity is generated by coal power engineering. However, in the process of burning coals, radioactive nuclides are concentrated in ash and slag waste. In the fuel power industry of Kazakhstan, high-ash coals with low concentrations of radionuclides are mainly used. The average contents of uranium and thorium are close to the clarke values. The natural radioactivity of coal and of ash and slag waste from Karaganda GRES-1, which consumes Ekibastuz coals with an ash content of 32–39%, was studied. The average values of the specific activities of U²³⁸, Th²³², and K⁴⁰ in 25 coal samples were 27.9 Bq/kg, 19.5 Bq/kg, and 81.0 Bq/kg, respectively. In ash and slag waste, the concentrations of these radionuclides were several times higher. The concentration coefficients of the studied radionuclides varied within the ranges of 4.7–5.5 for U, 3.8–5.7 for Th, and 4.2–8.6 for K⁴⁰. It was established that during coal combustion in thermal power plants, due to carbon combustion and the removal of volatile compounds, not only natural radionuclides but also many microelements, including toxic ones (Mn, Cd, Ni, Co, Zn, etc.), are concentrated in the ash. Full article

The use of UAVs to map ionising radiation resulting from radioactive decay is gaining popularity among researchers due to its efficiency and safety. Many studies have been conducted, most of them using expensive sensors. The present research aims to investigate the applicability of an affordable radiation detector in areas where anomalies from natural sources occur. In this research, we use a DJI Matrice 210 V2 RTK quadcopter equipped with a cost-effective Safecast bGeigie Nano Kit radiation sensor to take measurements at different altitudes above ground. We convert these data into GIS-compatible formats and produce accurate isoline maps using the Minimum Curvature interpolation technique. The results show that while the radiation intensity decreases with height, the anomaly was visible but less detailed at all heights investigated. In addition, the study highlights the significant differences in position measurements between RTK GNSS and autonomous GNSS measurements that affect the accuracy of the data. The results will contribute to a more accurate determination of the radiation extent and, thus, to maintaining safety, as well as assisting in emergency surveys and environmental monitoring. Full article

Neutrinoless double beta decay ($0\nu \beta \beta$) provides a way to probe physics beyond the Standard Model of particle physics. The upcoming nEXO experiment will search for $0\nu \beta \beta$ decay in ¹³⁶Xe with a projected half-life sensitivity exceeding ${10}^{28}$ years at the 90% confidence level using a liquid xenon (LXe) Time Projection Chamber (TPC) filled with 5 tonnes of Xe enriched to ∼90% in the $\beta \beta$-decaying isotope ¹³⁶Xe. In parallel, a potential future upgrade to nEXO is being investigated with the aim to further suppress radioactive backgrounds and to confirm $\beta \beta$-decay events. This technique, known as Ba-tagging, comprises extracting and identifying the $\beta \beta$-decay daughter ¹³⁶Ba ion. One tagging approach being pursued involves extracting a small volume of LXe in the vicinity of a potential $\beta \beta$-decay using a capillary tube and facilitating a liquid-to-gas phase transition by heating the capillary exit. The Ba ion is then separated from the accompanying Xe gas using a radio-frequency (RF) carpet and RF funnel, conclusively identifying the ion as ¹³⁶Ba via laser-fluorescence spectroscopy and mass spectrometry. Simultaneously, an accelerator-driven Ba ion source is being developed to validate and optimize this technique. The motivation for the project, the development of the different aspects, along with the current status and results, are discussed here. Full article

With the development of nuclear energy in China, the geological disposal of high-level radioactive waste (HLW) is increasingly receiving national attention. Among them, the study of nuclide migration is an important and complex technical system, which requires continuous in-depth research. Under the decay heat, radiation, and groundwater effects of HLW, buffer materials generate complex coupled thermo-hydro-mechanical-chemical (THMC) processes. The migration and diffusion of nuclides in buffer materials are controlled by the coupling effect of THMC. It is of great significance for the long-term safety of a HLW repository to study the long-term retarding effect of buffer material on nuclide strontium under the coupling effect of multiple factors. This study leverages the solving advantages of COMSOL Multiphysics 5.6, using a combination of the self-developed Mock-up experimental device as a geometric model and numerical simulations to study the multi-field coupling performance and radionuclide migration evolution characteristics of THMC buffer materials, which overcomes the difficulties due to the limitations of the experimental time and spatial scale. The simulation results can predict the migration range and distance variation of strontium in buffer materials at different time scales. In the initial stage, the migration and diffusion of nuclide in buffer materials are relatively slow, and the migration distance increases by about 0.03 m with time. In the mid-to-late stage, the migration distance increases by about 0.05 m over time; to ensure that, in 1000 years, core strontium does not penetrate the buffer material and migrate into the surrounding rock groundwater of the disposal facility, a buffer material thickness of 0.3 m needs to be set. The construction of THMC control equations for the migration and diffusion of nuclides in buffer materials under multi-field coupling conditions has been revealed, providing an important reference for a deeper understanding of the risk analysis of radionuclide contamination in disposal environments. Full article

The raw materials of cement contain radioactive elements that come from natural sources. Members of the decay chains of uranium, thorium, and potassium radioisotope ⁴⁰K are the primary sources of this radioactivity. The natural radionuclide concentration levels in cement differ greatly depending on different geographic areas. To estimate the radionuclides concentration in cement specimens from twelve diverse Pakistani companies, gamma-ray spectroscopy analysis was used in the study. ²²⁶Ra, ²³²Th, and ⁴⁰K had activity concentration levels ranging from 18.08 to 43.18 Bq/kg, 16.73 to 23.53 Bq/kg, and 14.24 to 315.22 Bq/kg, respectively. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) threshold for the ²²⁶Ra was surpassed by five of the studied samples. The indoor and outdoor dose rates as well as different radiological health hazard indices were also examined. The Indoor Absorbed Dosage (D_in) for some of the samples exceeded the permissible limit. These samples also had a high Indoor Effective Lifetime Cancer Risk (ELCR) factor, which makes them unsafe for interior construction purposes. The outdoor dosages as well as the hazard indices were well within the permitted ranges. The outdoor ELCR factor is low for all the cement brands, which makes them safe for exterior construction purposes. The findings were compared with published data from other countries around the globe. Finally, a thorough statistical analysis was performed and Pearson’s Correlation Coefficient (r) exhibited a very strong correlation between the different outdoor and indoor radiological health hazard indices. Full article

Laboratory-scale experiments were conducted on Carboniferous Limestone gravels from the Mendip Hills area, England; sandstones from the Pirambóia and Botucatu formations, Paraná sedimentary basin, Brazil; samples of schist and quartzite from Caldas Novas Hydrothermal Complex, Brazil; and the minerals tantalite, cassiterite, and columbite from mining areas at Rio Grande do Norte State, Brazil, with the purpose of evaluating the release of ²²²Rn to the water phase. The specific surface area of the samples corresponded to 1.69–81.36 cm²g⁻¹, which provided values of 0.001–1.68 dpm/g and 3.18 × 10⁻⁶ to 0.59 for the radon released and radon emanation coefficient, respectively. These results allowed us to calculate the radon flux with respect to the radon leakage, which corresponded to values of 0.00016–0.00158 Bq/m²/d for the denser materials and 0.018–0.43 Bq/m²/d for limestones and sandstones. They also permitted us to find an inverse, significant relationship between the radon generated by the minerals/rocks and the radon flux into the water phase, which was tested for sediments in coastal and inland Brazilian areas, demonstrating utility for evaluating the diffusive radon flux from the sediments, which is an important parameter to monitor submarine groundwater discharge (SGD) by means of radon as a natural tracer. Full article

In this research, we investigated the observed spectra of the hot peculiar star HD25354 with an effective temperature $T_{\mathrm{eff}}$ = 12,800 K, identified the lines of radioactive chemical elements, including the elements with short decay time, and estimated the abundances of these elements. We tried to confirm or reject the existence of promethium lines and lines of other radioactive elements which were detected in previous investigations of this star and explain the physical mechanisms which are responsible for the synthesis of these elements in the stellar atmosphere. We used two high-dispersion spectra of HD25354 observed with the 2 m telescope of Terskol observatory with resolving power near R = 60,000, and a signal to noise ratio near 200. The spectrum of the star from the archive of the 1.93 m telescope of Haute-Provence observatory was also used. The observations were compared with synthetic spectra and the abundance of promethium was found using the best four lines of this element in the observed spectra: $logN$(Pm) = 5.84 ± 0.16 in the scale logN(H) = 12. It is comparable to the abundances of stable lanthanides in the atmosphere of this star. The abundance of thorium derived from two lines of double-ionized thorium is $logN$(Th) = 3.59 ± 0.15. The upper limits for technetium, radium, actinium, uranium, and americium abundances are found to be equal to 4.0, 3.0, 1.25, 3.5, and 4.0, respectively. Maybe the existence of promethium lines and lines of other unstable chemical elements in the spectra of HD25354, as well as the other stars of our Galaxy, Magellanic Clouds, and Fornax dwarf galaxy, can be explained by contamination of its atmosphere by the products of kilonova outburst and by symmetric decay of chemical elements with long decay times located at the island of stability (atomic numbers Z = 110–128) of transfermium elements. Maybe the decay of superheavy elements of the island of stability can be one of the reasons for the enhanced abundances of rare earth lanthanides in different types of stars. Full article