Search Results (79)

Northwestern Jiangxi Province is rich in metasilicic acid (as H₂SiO₃) mineral water resources. Investigating their hydrogeochemical characteristics and formation mechanism is crucial for the rational utilization of water resources and the sustainable development of the local mineral water industry. Taking the Taoping water source area in northwestern Jiangxi as a case study, 11 sets of groundwater and surface water samples were systematically collected. By comprehensively applying mathematical statistics, ionic ratios, and isotopic analyses, the hydrogeochemical characteristics and formation processes of metasilicic acid-type mineral water were examined. The results indicate that: (1) The mineral waters in the area are weakly alkaline and belong to the metasilicic acid type, with concentrations ranging from 22.0 to 67.0 mg/L, of which 75% exceed 30 mg/L. (2) The primary hydrochemical types are HCO₃⁻–Ca·Na, HCO₃⁻–Ca·Mg, and HCO₃⁻–Ca. Analysis of stable isotopes (δ¹⁸O and δ²H) and tritium (³H) indicates that metasilicic acid mineral water is primarily recharged by atmospheric precipitation, with an apparent groundwater age of approximately 60 years. (3) The enrichment of metasilicic acid primarily results from the weathering and leaching of silicate minerals, coupled with cation exchange. K⁺ and Na⁺ are mainly derived from silicate minerals such as feldspars and halite, whereas Ca²⁺ and Mg²⁺ originate primarily from carbonate minerals like calcite and dolomite. During recharge, atmospheric precipitation infiltrates the aquifer, dissolving aluminosilicate and siliceous minerals in the surrounding rocks, thereby releasing metasilicic acid into the groundwater and ultimately forming the metasilicic acid-type mineral water. Full article

Tritium (³H) is a low-energy β emitter commonly found in environmental water samples, and its routine monitoring requires highly sensitive techniques capable of achieving low detection limits. Liquid scintillation counting (LSC) is the standard method for low-level ³H analysis; however, quenching significantly affects detection efficiency and minimum detectable activity (MDA), and systematic evaluations across different quench levels and measurement approaches remain limited. This study evaluates quench-related uncertainties in low-level ³H measurement using two ultra-low background liquid scintillation counters, Quantulus 1220 and GCT 6220. High- and low-quench conditions were created by varying sample-to-cocktail ratios, and performance was assessed through detection efficiency, minimum detectable activity (MDA), and stability. Under the relative measurement method with limited quench variation, GCT 6220 achieved higher efficiency, lower background, and lower detection limits. Under the internal standard method with broader quench spans, Quantulus 1220 produced smoother efficiency–quench curves and more stable results. Thus, GCT 6220 is advantageous for sensitivity-demanding scenarios, while Quantulus 1220 is better suited for quench-correction applications. Full article

Specifically engineered heavy liquid metals are proposed as candidate coolants and tritium breeders for advanced nuclear applications. Understanding the wetting behaviours of these liquids on relevant substrate configurations is crucial to tackle the challenges associated with corrosion protection and flow diagnostics development. However, detailed investigations are scarce in the literature. In this experimental study, an apparatus is designed to measure contact angles of different liquid metals over a mirror-polished horizontal SS-304 substrate. This paper presents design aspects of the developed test facility, as well as initial results obtained using direct imaging and the Low-Bond Axisymmetric Drop Shape Analysis algorithm-based image processing technique. Methodological validation is achieved through surrogate liquids/liquid metals (H₂O, Hg, Ga, GaInSn), prior to taking measurements from molten lead (Pb) droplets at 425 °C. Estimated contact angles obtained using the two techniques lie within ±10% deviation. Towards the end, the paper lays out plans for future upgrades for studies of wetting behaviours of molten Pb/Pb alloys on substrates with relevant surface properties, including bare P-91 and reduced-activation ferritic–martensitic steels, along with Al₂O₃/Er₂O₃-coated versions of these materials, to generate a database for Gen-IV fission reactors and fusion power plants. Full article

Groundwater recharge sources and residence times in the Sulaimani–Warmawa Sub-basin, located in the Kurdistan Region of Iraq, were assessed through an integrated hydrogeological, hydrochemical, and isotopic investigation. The study area, located around Sulaimani City, is characterized by a semi-arid climate with precipitation predominantly occurring during winter and early spring. Hydrochemical results indicate groundwater types ranging from Ca–HCO₃ to Mg–Ca–HCO₃, accompanied by a progressive increase in electrical conductivity along the regional flow path. Stable isotope signatures (δ²H and δ¹⁸O) show that groundwater is primarily recharged by winter precipitation derived from both Eastern Mediterranean and Persian Gulf air masses. Two groundwater groups were identified based on isotopic composition and tritium content: recently recharged groundwater and older groundwater, represented by two samples. Tritium values ranging from 0.8 to 4.9 TU correspond to minimum residence times from less than 10 years to approximately 40 years. Higher tritium concentrations near recharge zones reflect recent infiltration, whereas lower values indicate older groundwater with limited modern recharge. The piston flow model provided the best fit for tritium data, suggesting limited mixing and relatively rapid subsurface flow. Samples with higher salinity likely reflect reduced flushing in low-permeability zones, resulting in elevated dissolved solids. Hydraulic-data-based estimated groundwater flow velocities yielded lower values compared to tritium-based estimates, implying preferential flow in karstified formations. The relatively short groundwater residence times mean there is high vulnerability to contamination, emphasizing the need for careful land-use planning and groundwater protection strategies. Full article

Groundwater and water supply systems are increasingly vulnerable to contamination, yet most assessments consider either hydrogeological or infrastructure risks. This study introduces the Total Integrated Network (TIN) approach, a framework designed to evaluate vulnerability comprehensively from source to tap. Field investigations were conducted in Varaždin County, Croatia, focusing on the Belski Dol spring, Briška reservoir, and PS Filipići. Hydrochemical analyses, stable isotope of water (δ¹⁸O, δ²H), tritium, noble gases, and radon concentrations were monitored and combined with system-level assessments. Results show that the Belski Dol spring exhibits high stability and low vulnerability, with a TIN index of approximately 25%, supported by long groundwater residence times and consistent water quality. PS Filipići displayed moderate vulnerability (35%), while the Briška reservoir showed the highest index (53%), linked to elevated radon and nitrate concentrations and infrastructure-related risks. These findings indicate that natural hydrogeological protection alone cannot ensure safe drinking water. The TIN approach highlights the importance of integrating aquifer conditions with distribution system performance to identify critical control points and prioritize interventions. This integrated methodology offers a more realistic basis for water safety management, supporting proactive measures to safeguard supply resilience and public health. Full article

The Puebla Metropolitan Area, one of the most industrialized regions in Mexico, shows severe contamination of both surface and groundwater. In this study a multi-tracer approach combining hydrochemistry with environmental isotopes (δ²H, δ¹⁸O, ³H) was applied to evaluate groundwater–surface water (GW–SW) interactions and their role in water quality degradation. Elevated concentrations of aluminum, iron, zinc, and lead were detected in the Alseseca and Atoyac Rivers, exceeding national standards, while arsenic, manganese, and lead in groundwater surpassed Mexican and WHO drinking water limits. The main sources of contamination include volcanic inputs from Popocatepetl activity (e.g., arsenic) and untreated discharges from industrial parks (e.g., lead), which together introduce significant loads of Potentially Toxic Elements (PTEs) into surface and groundwater. Isotopic analysis identified three sources for aquifer recharge: (1) recharge from high-altitude meteoric water, (2) mixed GW–SW water recharged at intermediate elevations with heavy metal presence, and (3) recharge from lower altitudes (evaporate water). Tritium confirmed both modern and old recharge, while isotope-based mixing models indicated surface water contributions to groundwater ranging from 18% to 72%. These interpretations were derived from the integrated analysis of hydrochemical and isotopic data, allowing the quantification of recharge sources, residence times, and mixing processes. The results demonstrate that hydraulic connectivity, enhanced by fractures and faults, facilitates contaminant transfer from polluted rivers into the aquifer. Full article

Eggshell membrane (ESM) is composed of approximately 90% protein. Our previous studies in healthy adults demonstrated that two months of daily ESM intake improved respiratory function, zigzag walking speed, and skin elasticity. The present study aims to address the knowledge gap regarding the in vivo effects of ESM in the context of inflammatory bowel disease (IBD). Proteomic analysis was performed on powdered ESM used as a dietary supplement. To investigate its pharmacokinetics in mice, tritium (³H)-labeled ESM was prepared using the ⁶Li(n,α)³H nuclear reaction. The therapeutic potential of ESM was further examined in a 2.0% dextran sulfate sodium (DSS)-induced murine model of IBD. In addition, fecal samples from both mice and healthy human subjects were analyzed using a modified terminal restriction fragment length polymorphism (T-RFLP) method. Lysozyme C (LYZ) was the most abundant protein (47%), followed by lysyl oxidase (12%) in ESM used in this study. ³H-ESM was mixed with MediGel, and orally administered to mice. Radioactivity levels were measured in blood, organs (duodenum, small intestine, large intestine, liver, kidney, lung, skin), and rectal feces at 0.5, 2, 5, 24, 48, and 72 h post-administration. Radioactivity in feces indicated excretion of undigested components, while systemic distribution suggested potential whole-body effects of ESM. Oral ESM and LYZ significantly alleviated body weight loss, diarrhea, and hematochezia in a DSS-induced murine model of IBD, leading to a significantly lower disease activity index on day 3 and showing a similar trend on day 5. Gut microbiota analysis showed increased Bacteroidales in the DSS group, while the ESM + DSS group maintained levels similar to the control. In humans, a double-blind, randomized controlled trial was conducted to evaluate the effects of ESM on gut microbiota in healthy adults. Participants received either ESM or placebo for 8 weeks. revealed a significant increase in alpha diversity at weeks 1 and 8 in the ESM group (p < 0.05), with between-group differences evident from week 1 (p < 0.01). ESM intake reduced Bacteroides and significantly increased Bifidobacterium and Lactobacillales at weeks 4 and 8. These findings suggest ESM supplementation promotes beneficial modulation of gut microbiota. These findings suggest that ESM, through its major protein components such as LYZ, may serve as a promising dietary intervention for maintaining intestinal health and mitigating inflammation in the context of IBD. Full article

Geothermal resources in arid inland basins are important for clean energy development, yet their circulation and geochemical mechanisms remain insufficiently understood. This study investigates the hydrochemical characteristics and formation mechanisms of geothermal water in the Zhangye–Minle Basin, an arid inland region in northwestern China. A total of nine geothermal water samples were analyzed using major ion chemistry, stable isotopes (δ²H, δ¹⁸O), tritium (³H), and radiocarbon (¹⁴C) to determine recharge sources, flow paths, and geochemical evolution. The waters were predominantly of the Cl–Na and Cl·SO₄–Na types, with total dissolved solids ranging from 3432.00 to 5810.00 mg/L. Isotopic data indicated that recharge originated from atmospheric precipitation and snowmelt in the Qilian Mountains, with recharge altitudes between 2497 and 5799 m. Tritium and ¹⁴C results suggested that most samples were recharged before 1953, with maximum ages exceeding 40,000 years. Gibbs diagrams and ion ratio plots demonstrated that water–rock interaction was the primary geochemical process, while cation exchange was weak. Na⁺ was mainly derived from halite, albite, and mirabilite, while SO₄²⁻ originated largely from gypsum. The calculated reservoir temperatures using cation geothermometers ranged from 57 °C to 148 °C. The deep circulation of geothermal water was closely related to NNW-trending fault zones that facilitated infiltration and heat accumulation. These findings provide new insights into the recharge sources, circulation patterns, and geochemical processes of geothermal systems in fault-controlled basins, offering a scientific basis for their sustainable exploration and development. Full article

This study presents long-term observations of tritium (³H) concentrations in the Neris River at monitoring sites located near the Belarus–Lithuania border and in the city of Vilnius. Since the commissioning of the Belarusian Nuclear Power Plant (BelNPP), ³H levels in the river have consistently exceeded natural background values, with pronounced temporal variations. These fluctuations are attributed to routine ³H releases from the BelNPP, with increased concentrations observed during scheduled maintenance periods. A ³H transport model was developed to estimate the downstream propagation of releases and to assess the time lag between upstream discharge events and their detection at downstream locations. The model reliably simulates ³H behavior in flowing water and can be adapted to future scenarios and other water-soluble radionuclides, provided that isotope-specific and hydrological data are available. These findings highlight the importance of continued monitoring and further research on the fate and transport of radioactive substances in transboundary river systems. Full article

A vital step for any hydrochemical assessment is properly carrying out quality assurance and quality control (QA/QC) techniques to evaluate data confidence before performing the assessment. Understanding the processes governing groundwater evolution in coastal aquifers is critical for managing freshwater resources under increasing anthropogenic and climatic pressures. This study reassesses the hydrochemical and isotopic data from the Deep Confined Aquifer System (DCAS) in the Jiangsu Coastal Plain, China, by firstly applying QA/QC protocols. Anomalously high Fe and Mn concentrations in several samples were identified and excluded, yielding a refined dataset that enabled a more accurate interpretation of hydrogeochemical processes. Using hierarchical cluster analysis (HCA), principal component analysis (PCA), and stable and radioactive isotope data (δ²H, δ¹⁸O, ³H, and ¹⁴C), we identify three dominant drivers of groundwater evolution: water–rock interaction, evaporation, and seawater intrusion. In contrast to earlier interpretations, we present clear evidence of active seawater intrusion into the DCAS, supported by salinity patterns, isotopic signatures, and local hydrodynamics. Furthermore, inconsistencies between tritium- and radiocarbon-derived residence times—modern recharge indicated by ³H versus Pleistocene ages from ¹⁴C—highlight the unreliability of previous paleoclimatic reconstructions based on unvalidated datasets. These findings underscore the crucial role of robust QA/QC and integrated tracer analysis in groundwater studies. Full article

Tritium is a radioisotope that is extremely mobile in the biosphere and that can be transferred to the environment and to humans mainly via tritium oxide or tritiated water. Moreover, as is widely known, it is extremely difficult to detect in the environment. In the last decade, many studies and research activities have been performed to fill the knowledge gap on this radionuclide, the amount of which is expected to be increasingly released into the environment from nuclear installations in the near future. Considering this and the fact that the biological and environmental effects produced by tritium have been examined mainly from a medical and detection monitoring point of view, it is considered important to propose in this study a review of the critical aspects of tritium from the environmental, engineering, and waste management points of view. Identifying sources and effects of tritium, tritium materials and wastes containing tritium in the environment is also fundamental for planning the specific and necessary actions required for an effective waste management approach under, e.g., disposal conditions. The critical analysis of the published recent studies has allowed to evaluate, for example, that the expected rate of tritium generation in a fusion reactor is four orders of magnitude higher than that of LWRs, and the environmental release from a fusion reactor is 1.4–2.2‱, which is twice as much as from a heavy water reactor and more than two orders of magnitude higher than from a LWRs. Furthermore, with reference to the waste management strategy, it is emphasized, e.g., that the condensation of moisture inside vaults and the interaction of H₂O with the disposal body determine the formation of tritiated water, which is filtered through the concrete and eventually released into the environment. Consequently, in the selection of engineered barrier materials for repositories/disposal facilities, the use of a mixture of a framework and layered silicates is proposed to improve its absorption and filtering properties. Full article

This study describes a monolithic silicalite-1 catalyst support designed for tritium oxidation reactions under humid conditions. Monolithic molecular sieves (sil-s) were fabricated by converting silica binders to silicalite-1 through secondary crystallization (175 °C, 24 h). In addition to the binder conversion to silicalite-1, some recrystallization of starting silicalite-1 (sil) results in higher crystallinity, lower concentration of silanol defects, and higher hydrophobicity. With the addition of 2% platinum, Pt/sil-s exhibited better stability under humid conditions, showing only 0.01%/min conversion decay over 800 min. This work has demonstrated a moisture-resistant Pt catalyst for tritium oxidation in fusion energy systems. Full article

Enriched lithium isotopes (⁶Li and ⁷Li) are essential in the nuclear energy industry, where ⁶Li is bombarded with neutrons to produce tritium for fusion reactions, while ⁷Li is used as a core coolant and pH regulator. Separation of ⁶Li and ⁷Li by electromigration is a promising method for producing enriched lithium isotopes that fulfill industrial needs. In this work, based on a previously proposed biphasic system electromigration routine, a three-stage system of ‘LiCl aqueous solution (anolyte)|B12C4-[EMIm][NTf₂] organic solution|NH₄Cl aqueous solution (catholyte)’ was constructed and the rules of lithium isotope separation and lithium-ion migration investigated. It was shown that the isotope enrichment effect of the catholyte was greatly affected by the experimental conditions, while that of the organic solution was less affected. As the B12C4 concentration increased, enhancement of ⁷Li enrichment in the catholyte and ⁶Li enrichment in the organic solution was observed, and α(C/O) and α(O/A) reached 0.975 and 1.018 at B12C4 of 0.5 mol/L. With the increase in current, migration time, and LiCl concentration, the isotope that was enriched in the catholyte trended from ⁷Li to ⁶Li (about 6 mA, 12 h or LiCl of 5 mol/L). Taking lithium-ion transport efficiency and lithium isotope separation effect into consideration together, a current of at least 6 mA, duration of at least 12 h, LiCl concentration of at least 1 mol/L and B12C4 concentration of 0.2 mol/L are suggested for the electromigration process. The work provides an important reference for system construction and experimental design of a biphasic electromigration separation method, which is expected to be an industrial alternative because of its environmental protection and high efficiency. Full article

The long-term cultivation of apple trees with deep root systems can significantly deplete moisture from the deep soil layers, while extreme rainfall events can rapidly replenish this moisture. Therefore, it is of great academic significance to investigate the influence of extreme precipitation on soil water dynamics in apple orchards of varying ages. This study was conducted on agricultural land and apple orchards of 12 years, 15 years, 19 years and 22 years (12 y, 15 y, 19 y and 22 y) to examine the impact of extreme precipitation on soil moisture transport. Soil moisture content and hydrogen and oxygen isotope (²H, ¹⁸O and ³H) data were collected before (October 2020 and May 2021) and after the extreme precipitation event (May 2022). This comprehensive analysis focuses on two aspects: soil moisture distribution and soil water recharge. The following main conclusions were drawn: (1) Extreme precipitation significantly enhanced deep soil water recharge in apple orchards: the depths of soil water supply for apple orchards of 12 y, 15 y, 19 y and 22 y were recorded as 282 mm, 180 mm, 448 mm and 269 mm, respectively. Correspondingly, the recharge depths were measured at approximately 12, 10, 10 and 7 m, respectively. It was observed that the recharge depth decreased with increasing age of the orchard. (2) Extreme precipitation did not have a significant impact on the values of δ²H and δ¹⁸O of deep soil moisture due to a limited infiltration depth through the piston flow mechanism (the maximum infiltration depth being around 3 m). (3) In agricultural land as well as apple orchards of 12 y, 15 y and 22 y in 2020, the tritium peak occurred at soil depths of 7.2, 6.9, 6.7 and 5.7 mm, respectively; in 2022, the corresponding values increased to 7.9, 8.7, 6.7 and 5.9 mm, respectively. This indicates that planting apple trees hindered the transport of soil moisture. The peak concentration of tritium in both agricultural land and different-aged apple orchards decreased after experiencing extreme precipitation. The findings will provide a scientific basis for water resource management and efforts toward ecological restoration on the Loess Plateau. Full article

The Liquid Phase Catalytic Exchange (LPCE) process plays a pivotal role in the separation of hydrogen isotopes, particularly in applications such as tritium removal in heavy water reactors. Effective separation is crucial for maintaining reactor safety and efficiency. In this study, the optimal operating conditions for the LPCE process were determined through orthogonal experiments and validated in different hydrogen isotope systems. The experiments investigated key operational parameters, including the filling ratio of catalyst to packing (FR), operating temperature (T), superficial gas velocity (V), and gas-to-liquid flow rate ratio (λ), using a robust L₁₆ orthogonal experiment design. The results indicated that V and FR had the most significant effects on the height equivalent to a theoretical plate (HETP), while λ exhibited the greatest impact on dedeuterization efficiency (DE). The optimal conditions obtained were V = 0.1 m/s, FR = 1:2, T = 70 °C, and λ = 2.5. Furthermore, the reproducibility of the optimal conditions was verified in LPCE columns with varying diameters (1.5 cm, 2.5 cm, 4.5 cm). Additionally, the findings were applied to both H-D and D-T separation systems, demonstrating consistency in mass transfer efficiency and validating the applicability of the optimal conditions in different hydrogen isotope separations. This research provides critical insights for optimizing tritium removal systems in heavy water reactors, contributing to enhanced reactor safety and performance. Full article