Search Results (260)

Hospital wastewater has begun to act as an important source of emerging contaminants, including rare earth elements (REEs), mostly lanthanides, and radiopharmaceutical residues originating from diagnostic and therapeutic nuclear medicine procedures. The increasing use of gadolinium-based contrast agents, lutetium-containing therapeutics, technetium-99m tracers, iodine-131, yttrium-90, and gallium-68 radiopharmaceuticals has raised growing concerns regarding the release of radioactive and metal-containing compounds into aquatic environments. Conventional wastewater treatment plants are often inefficient in removing these contaminants because of their high chemical stability, low environmental concentrations, and complex aqueous speciation. In this context, hybrid nanomaterials containing silver nanoparticles (AgNPs) have attracted increasing interest for both monitoring and remediation applications. AgNP-based systems exhibit unique plasmonic, catalytic, antimicrobial, and sensing properties that can be exploited in adsorption, photocatalysis, membrane filtration, electrochemical detection, and surface-enhanced Raman spectroscopy (SERS). This review critically analyzes recent advances in hospital wastewater treatment and how hybrid nanomaterials containing silver nanoparticles (AgNPs) are emerging. The review places a particular focus on contamination by REEs and radiopharmaceuticals residues, which to date, as far as we know, remains a challenging and understudied aspect, as reflected by limited publications. Full article

Uranium is a naturally occurring radioactive heavy metal, and drinking water and food are the primary sources of non-occupational exposure for the general population. The aim of the present study was to evaluate urinary uranium concentrations among cancer patients and healthy residents living in uranium legacy-affected areas and to compare them with those of individuals residing in a region with a more favorable radiological environment, accounting for urinary creatinine levels. An observational human biomonitoring study was conducted among 80 adults divided into four groups (n = 20 each): cancer patients and healthy residents from the exposed area and cancer patients and healthy residents from the comparison area. Twenty-four-hour urine samples were analyzed for uranium using inductively coupled plasma mass spectrometry, and urinary creatinine was measured using the kinetic Jaffe method. Urinary uranium concentrations ranged from 0.01 to 1.30 µg/L, with the highest values observed in cancer patients from the exposed area. After creatinine adjustment, median uranium concentrations were 0.0974 µg/g creatinine in exposed cancer patients, 0.0888 µg/g creatinine in exposed healthy residents, 0.0515 µg/g creatinine in comparison-area cancer patients, and 0.0607 µg/g creatinine in comparison-area healthy residents. Significant differences were observed between exposed and comparison populations among both cancer patients (p = 0.0066) and healthy residents (p = 0.0499). Residence in the exposed area was positively associated with urinary uranium levels (ρ = 0.292, p = 0.012). These findings suggest higher internal uranium exposure among residents of uranium legacy-affected areas and support the use of urinary uranium as a biomarker of environmental exposure. This study contributes to the assessment of internal uranium exposure in residents of uranium legacy-affected areas, including both cancer patients and healthy residents. However, the findings should be interpreted as differences in exposure biomarkers and do not establish a causal relationship between uranium exposure and cancer. Full article

Photocatalytic extraction of uranium from radioactive wastewater is crucial for environmental safety and sustainable nuclear energy development. It is widely recognized that photocatalysts with donor-acceptor (D-A) or D-π-A structures exhibit enhanced charge separation efficiency, thereby showing excellent photocatalytic performance. Herein, we presented a counterintuitive design of a donor-donor covalent-organic framework (D-D COF) for efficient photocatalytic uranium extraction. A twisted D-D COF (COF-BCTB-Py) was synthesized via solvothermal condensation using bicarbazole and pyrene as dual electron-donor units. The COF featured a well-defined AA-stacked porous structure, high specific surface area (963 m²·g⁻¹), suitable band gap (2.44 eV), and exceptional chemical, thermal, and radiation stability. Impressively, in the presence of 5% methanol, it delivered an ultrahigh uranium uptake capacity of 4278 mg·g⁻¹ with fast kinetics and >97% removal efficiency in complex water matrices, challenging the traditional stereotype of low-activity D-D COFs. Mechanistic studies revealed that soluble U(VI) was converted into crystalline (UO₂)O₂·2H₂O via in situ generated hydrogen peroxide rather than being reduced to U(IV). This work provides an unconventional design strategy to design efficient photocatalysts for uranium recovery from nuclear wastewater. Full article

The Gebel Shalman-Wadi Biarn (GSh-WB) area in Egypt’s South Eastern Desert hosts NYF-type rare-metal pegmatites with significant U, Th, Nb-Ta, and REEs mineralization. This study integrates field observations, petrography, mineralogy, whole-rock geochemistry, and gamma-ray spectrometry to characterize these pegmatites and evaluate their economic potential. The pegmatites occur as veins, dykes, and zoned pockets hosted entirely within syenogranites. Petrography, pegmatites, and syenogranites are primarily composed of K-feldspar, albite, and quartz with trace amounts of biotite and muscovite. The environmental scanning electron microscope (ESEM) revealed the presence of the following minerals: autunite, kasolite, thorite, monazite-(Ce), parisite, xenotime-(Y), ferrocolumbite, hydroxyplumbobrtafite, aeschynite-(Y), and zircon, which are the major U-Th, Nb-Ta, and REE-bearing minerals. Additionally, gold, cassiterite, wolframite, pyrrhotite, chalcopyrite, and brass alloy were identified as sources of precious and base metals. Both groups’ chondrite-normalized REE patterns, which display slightly elevated LREE patterns and negative Eu anomalies, point to fractional crystallization involving plagioclase fractionation. Consequently, pegmatite and syenogranites are believed to have mostly formed from the partial melting of a reconstituted juvenile crust and its weathered sediments associated with Neoproterozoic magmatism. The marginally positive Ce anomaly in the (GSh-WB) pegmatites (1.02–0.98) may be associated with monazite crystallization resulting from enhanced fractionation. The Th and U levels range from 101 to 28.6 ppm and from 51 to 5.8 ppm, respectively. The magnitude of the tetrad effect in the rare earth elements of the analyzed rocks exceeds one (T1 = 1.12–1.02, T3 = 0.92–1.08, and T1,3 = 1.01–1.05), suggesting an M-type tetrad effect. The presence of this tetrad effect is indicative of granite that has been significantly altered by hydrothermal processes and is extensively fractionated. Chondrite-normalized REE patterns of the pegmatites (average ΣREE = 439 ppm) and their host syenogranites (average ΣREE = 192 ppm) show similar trends characterized by enrichment of light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs) and pronounced negative Eu anomalies (Eu/Eu* = 0.09–0.22). These features, together with negative Sr and Ba anomalies, likely reflect extensive fractional crystallization of feldspars and feature anorogenic rocks. Spectrometric analysis reveals eU values of 2.0–288 ppm and eTh values of 7.0–455 ppm in pegmatite samples, with eU/eTh ratios (0.49–0.39) exceeding the typical continental crust value of 0.25, indicating uranium enrichment. Both magmatic and hydrothermal processes contributed to the observed radioactivity. The spatial distribution of uranium shows lithological and structural controls. The GSh-WB pegmatites represent a potential target for uranium exploration. Full article

Numerous promising cancer treatments currently in clinical trials rely on the production and purification of actinium-225 (²²⁵Ac), an actinide with alpha emissions that can kill cancer cells via targeted alpha therapy. To enable ongoing and future studies, and to support anticipated future demand, it is necessary to increase the supply of ²²⁵Ac. High-energy proton irradiation of thorium metal (Th⁰_(s)) is one of the leading production methods of ²²⁵Ac. This process requires the chemical separation of microscopic amounts (μg) of ²²⁵Ac from large quantities (>10 g) of thorium. Current methods to accomplish this thorium removal step can be slow, tedious, generate large quantities of radioactive liquid waste, and require very strict control of the processing conditions. To improve this separation, we investigated the ability of four nitrate salts (NH₄NO₃, KNO₃, RbNO₃, and CsNO₃) to act as selective Th⁴⁺ _(aq) precipitation agents in the presence of ²²⁵Ac³⁺_(aq) in aqueous nitric acid to allow for their separation through a simple filtration. First, we used an automated separations platform to screen the ability of these nitrate salts to precipitate Th⁴⁺. We found the Th⁴⁺ precipitation yields and amount of precipitating agent needed to maximize this yield were dependent on the identity of the precipitating agent cation. Separation studies with ²²⁵Ac³⁺_(aq) and subsequent down-selection of the most promising Th⁴⁺ precipitating agents and conditions enabled us to develop its effective selective precipitation. We demonstrated that the separation was compatible with Th⁰_(s) quantities that can produce medically relevant amounts of ²²⁵Ac. We observed 99.9% of Th⁴⁺_(aq) could be removed via precipitation with KNO_3(s) in less than two hours in the presence of co-produced isotopes. Meanwhile, other experiments demonstrated that the ²²⁵Ac³⁺_(aq) recovery was > 97% at 1–10 g Th⁰_(s) scale. Full article

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

Emerging metallic radionuclides are expanding theranostic capabilities in nuclear medicine by improving diagnostic sensitivity, enabling dosimetry, and matched theranostic approaches. ¹⁴⁹Tb, ⁴⁴Sc, ⁵²Mn, ²⁰³Pb, and ⁵⁵Co offer distinct nuclear decay properties, including extended half-lives, variable positron emissions, and prompt γ-photons that may influence quantitative imaging performance. Cyclotron and generator routes integrating enriched targets and optimized separations support clinical-scale supply, while advances in chelation chemistry improve in vivo stability and imaging performance. Preclinical and early clinical data demonstrate that ¹⁴⁹Tb provides intrinsic α-therapy and PET imaging capability for theranostic use, ⁴⁴Sc enables extended imaging relative to ⁶⁸Ga, supporting delayed imaging and improved tumor-to-background contrast for peptide-based radiopharmaceuticals and theranostic applications. ⁵²Mn supports prolonged biological tracking for antibody- and engineered-protein-targeted studies, whereas ²⁰³Pb serves as a diagnostic surrogate for ²¹²Pb based α-therapy (via ²¹²Bi). ⁵⁵Co PET imaging supports the development and evaluation of ^58mCo Auger electron therapy. Current challenges include limited global availability of highly enriched targets, management of long-lived radioactive by-products, and the need for standardized dosimetry and regulatory pathways to ensure reproducibility and safety. Ongoing developments in automated target handling, optimized separations, next-generation chelators, and harmonized regulation may facilitate broader clinical translation. Full article

Coastal environments are becoming more susceptible to enrichment of trace elements from human activities and natural processes. This research presents a detailed assessment of heavy metal pollution and radiological risks in coastal sediments from the Ras Mohamed area, South Sinai, at the northern Red Sea. Fifteen surface sediment samples were examined for nine trace metals and naturally occurring radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) using ICP-OES and gamma spectrometry techniques, respectively. Geochemical analyses showed the concentration sequence Fe > Ba > V > Cr > Zn > Co > Ni > Cu > Pb, where average levels of Cr, V, and Co were higher than Canadian Soil Quality Guidelines (CSQGs) and global crustal background values. Environmental evaluation using the pollution load index = 2.16 reflected ongoing contamination, and the Geo-Accumulation Index indicated low to moderate polluted sediment conditions. Nevertheless, ecological risk results (PERI = 87.21) together with toxicity indicators pointed to low to moderate biological effects. Human exposure assessments for adults and children revealed no significant non-carcinogenic risk (HI < 1), and the Total Cancer Risk remained below the acceptable regulatory threshold (1 × 10⁻⁴). From the other side, all recorded radiation activities were low, falling below internationally recognized safety limits. An evaluation of radiological hazard indices further confirmed that the sediments present no significant radiation risk, as all measurements remain within the low-level classification of international standards. Overall, the results indicate that although localized sediment transport and tourism-related pressures have increased certain metal levels, the region is radiologically secure and currently presents negligible risk to human health. Full article

Water scarcity has become a major challenge for agriculture, particularly in arid and semi-arid regions where irrigation is essential for sustaining crop and forage production. As freshwater supplies face growing pressure from climate change, urban growth, and industrial use, there is increasing interest in exploring alternative water sources to support sustainable agriculture. Produced water, a byproduct of oil and gas extraction, may represent an alternative water source in water-limited regions like the southwestern United States and the Middle East. However, raw produced water often contains high levels of salinity, trace metals, hydrocarbons, and naturally occurring radioactive materials, which cause risks to soils, crops, livestock, and food systems. This review synthesizes peer-reviewed studies up to January 2026 and reports on the agricultural application of treated produced water, focusing on its effects on soil properties, crop growth, yield, and forage nutritive quality. Existing research shows that treated produced water could be used for grain as well as forage crops under controlled conditions, but poorly treated and managed applications can lead to increases in soil salinity, structural degradation, reduced nutrient uptake, and hindered crop performance. In forage systems, irrigation with treated produced water has also been associated with changes in nutritive value, increasing concerns for livestock health. Several knowledge gaps remain, including limited long-term field studies, insufficient information on crop-specific contaminant thresholds, incomplete assessment of treatment and remediation strategies under different environmental conditions, and the absence of a consistent framework for classifying the chemistry of treated produced water for agricultural applications. Addressing these gaps through integrated soil, crop, and water research and the development of clear policies and guidelines is essential for determining whether treated produced water can be safely and sustainably used in agriculture under growing water scarcity. Full article

This article reviews the state of the art of laser ablation and deposition techniques applied so far to more than 50 elements, including metals, metalloids and lanthanides, yielding a wide variety of compounds in the form of thin films. Laser deposition processes have been performed in high-vacuum (HV) reactors at pressure values ranging between 10⁻¹ and 10⁻⁵ Pa, namely pulsed laser deposition (PLD), or, under different reactive gas ambient (O₂, N₂, CH₄, NH₃ and many others), so-called reactive pulsed laser deposition (RPLD), with the aim to form thin films with desirable chemical compositions. While a few metals have not been deposited as pure metallic films because they have no immediate technological interest, others, like alkali and alkaline earth metals, cannot be deposited in pure metallic form due to their very strong reactivity with oxygen, water vapor and hydrogen molecules which are always present, even in ultra-high-vacuum (UHV) systems, at pressure values of 10⁻⁵–10⁻¹⁰ Pa. Furthermore, elements of the Mendeleev periodic table with an atomic number higher than 88, such as actinides and synthetic elements, are dangerous to handle and deposit in the form of thin films due to their high radioactivity; therefore, they are excluded from this review. The inclusion of the non-metal thin films of carbon (C) and related chemical compounds prepared by PLD and RPLD in the present review is justified by the extensive research and the numerous scientific articles reported in the field. All the results obtained by PLD and RPLD techniques so far are discussed and presented in tabular format to guide the reader. Full article

The toxicity of radioactive metals arises from both chemical toxicity and radiotoxicity. ²¹⁰Pb(II) is a long-lived radionuclide in the decay chain of natural uranium series ²³⁸U and exhibits extremely high toxicity. Both ²¹⁰Pb(II) and Pb(II) are widely present in natural water bodies. However, their combined toxicity remains unclear. Based on this, this study used zebrafish embryos as model organisms to investigate developmental toxicity, behavioral toxicity, and thyroid disruption effects, through single and combined exposure to Pb(II) (0, 1, 10, 100 μg/L) and ²¹⁰Pb(II) (0, 100, 1000 Bq/L) for 120 h by comparing the radiotoxicity of ²¹⁰Pb(II) with the chemical toxicity of Pb(II) and further exploring their combined effects. The results showed that following exposure to different environmental concentrations of Pb(II) and environmental activity levels of ²¹⁰Pb(II), exposure to Pb(II) alone caused an increase in the malformation rate of zebrafish embryos, a decrease in locomotor activity, and significant upregulation of thyroid-related genes, including thyroid hormone receptor beta (TRβ) and corticotropin-releasing hormone (CRH) in the larvae. Exposure to ²¹⁰Pb(II) alone had no significant effects on zebrafish embryos. Notably, compared with the individual exposure groups, the toxic effects in the combined exposure group of Pb(II) and ²¹⁰Pb(II) were further significantly enhanced. Furthermore, correlation analysis indicated a positive correlation between malformations in zebrafish embryos and the expression of key genes in the hypothalamic–pituitary–thyroid (HPT) axis. These findings suggest that under combined exposure, the chemical toxicity of Pb(II) plays a dominant role, while the radioactive component ²¹⁰Pb(II) exerts a synergistic amplification effect. This study provides important scientific evidence for improving the environmental risk assessment of radioactive metals. Full article

Groundwater in uranium mining areas is highly sensitive to pollution by radionuclides and toxic elements, especially under in situ leaching mining, which increases their mobility. This study assesses the radiological and chemical features of water sources in the Chu-Sarysu uranium province (Kazakhstan) by evaluating the annual effective dose (AED) from radionuclide ingestion. In total, 98 water samples from boreholes, wells and rivers were analyzed for total alpha and beta activity, followed by radionuclide and chemical analysis of selected samples. High total alpha activity was detected mainly in groundwater and was associated with radium mobilization. On average, ²²⁸Ra constituted between 50% and 60% of the total AED, whereas ²²⁶Ra contributed between 35% and 45%, with uranium isotopes contributing less than 5%. The total AED value for the groundwater ranged from 0.14 to 0.52 mSv/year at average water use, but only one borehole sample had 9.07 mSv/year, reflecting a localized anomaly. Additionally, arsenic, manganese, and mercury displayed high spatial variability. These findings underscore radium’s significant role in radiation exposure and emphasize the need for comprehensive monitoring of both radiological and chemical contaminants in groundwater systems. Full article

The location of the decommissioned factory of plastics and chemical products Jugovinil, City of Kaštela, Croatia, has gained significant attention for urban development and the establishment of tourist facilities over the past three decades. Since the site is on the coast of the Adriatic Sea, on the shore of Kaštela Bay, where nautical tourism is already developed, plans for a five-star tourism complex were initiated. Given that the former industrial plant, its coal-powered power plant, and other later industrial activities (small shipyards) caused a certain degree of contamination with NORM (naturally occurring radioactive material) residues and heavy metals, an on-site detailed investigation was conducted into the spatial distribution and concentration evaluation of contaminants within dozens of soil samples, and the distributions of contaminants in the area of interest were shown in the form of maps. This study applies an integrated GIS and geostatistical framework to analyze the spatial distribution of multiple contaminants. Maps highlighting polluted zones are included, along with maps indicating areas with higher cumulative concentrations of contaminants. This paper provides an overview of potential issues related to the detected contaminants, as well as proposals for remediation methods before repurposing the site using retrospective data about sources of residues and contaminants. Full article

A structurally complex Paleozoic succession in southwestern Sinai hosts uranium and associated metals, and brittle deformation controls fluid flow and ore localization. The study integrates structural mapping with mineralogical, geochemical, and radiometric data to evaluate how fault architecture controls uranium and polymetallic mineral occurrences in the east Abu Zeneima area. Eleven representative samples were collected from major fault zones and host lithofacies, and 652 ground gamma-ray spectrometric measurements were acquired across mineralized localities and Paleozoic stratigraphic units. Heavy mineral separation, SEM–BSE/EDX, X-ray diffraction, and whole-rock geochemistry were used to identify ore and accessory phases and quantify their elemental composition. The middle carbonate member of the Um Bogma Formation is the primary host lithology and contains primary U dispersed within carbonaceous sandy dolostone and locally abundant secondary U phases coexisting with Cu–Fe–Mn phases and REE-bearing silicates and phosphates. Uranium enrichment (locally >2900 ppm eU) in the targeted anomalous samples shows a positive association with P₂O₅ and a weaker positive association with ΣREEs. Together with SEM–BSE/EDX and XRD identification of uranyl phosphates and REE-bearing accessory minerals, these observations suggest that phosphate-bearing secondary phases and REE-rich accessories locally contributed to uranium hosting. Seventy-four radioactive anomalies are predominantly associated with normal faults and are concentrated along fault cores and highly fractured downthrown blocks, especially along a NW–SE trend that forms the main mineralized corridor. The study findings emphasize the importance of fault zone architecture for targeting new uranium resources in Paleozoic basins. Full article

As the key technology of space exploration, space power has been a major area of international research focus. A lot of research work has been carried out around the world for the space nuclear reactor using the heat pipe, liquid metal and gas cooling methods. With the development of molten salt reactor in the Generation IV reactor system, molten salt dissolving fissile material and acting as a coolant at the same time has become a new cooling scheme, which provides new ideas for the design of space nuclear reactors. In this study, a novel reactor, the liquid-solid dual-fuel space nuclear reactor (LSSNR) was preliminarily proposed, combining the molten salt fuel and cross-shaped spiral solid fuel to achieve the design goals of 30-year lifetime and an active core weight of less than 200 kg. Monte Carlo neutron transport code OpenMC based on ENDF/B-VII.1 library was employed for neutronics design in the aspect of fuel type, cladding material, reflector material and the spectral shift absorber. Then, the thickness of the control drum absorber was optimized to meet the requirement of the sufficient shutdown margin, lower solid fuel enrichment, and 30-effective-full power-years (EFPY) operation lifetime. Finally, UC solid fuel with U-235 enrichment of 80.98 wt.% and B₄C thickness of 0.75 cm were adopted in LSSNR, and BeO was adopted as the reflector and the matrix material of the control drum. A spectral shift absorber Gd₂O₃ was used to avoid the subcritical LSSNR returning to criticality in a launch accident. The k_eff with the control drum in the innermost position is 0.954949, and the k_eff reaches 1.00592 after 30 EFPY of operation. The total mass of the active core is 158.11 kg. In addition, the thermal-hydraulic feasibility of LSSNR using cross-shaped spiral fuel was analyzed based on a 4/61 reactor core model. The structure of cross-shaped spiral fuel achieves enhanced heat transfer by generating turbulence, which leads to a uniform temperature distribution of the coolant flow field and reduces local temperature peaks. Based on the LSSNR scheme, some neutronic characteristics were analyzed. Results demonstrate that the LSSNR has strongly negative reactivity coefficients due to the thermal expansion of liquid fuel, and the fission gas-induced pressure meets safety requirements. One hundred years after the end of core life, the total radioactivity of reactor core is reduced by 99% and is 7.1305 Ci. Full article