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Groundwater occurrence in the Deccan basalt is highly uncertain. Non-invasive hydro-geophysical techniques, when integrated with a priori geological information, can aid in delineating saturated zones. This study uses electrical resistivity anisotropy with direct current (DC) resistivity and time-domain induced polarization (IP) for delineating groundwater prospects. We utilized the geophysical responses of DC resistivity, induced polarization, anisotropy and available borehole litholog data to locate the potential aquifers. Anisotropic inversion of DC resistivity data enables the identification of fractured basalt. We observed shallow saturation zones where fractured basalt overlies less permeable layers and deeper confined zones below the intertrappeans within fractured amygdaloidal basalts. The most productive shallow aquifers exhibit low to moderate resistivity (1 to 36 Ωm), and moderate to low chargeability (1.1 to 8 mV/V) and anisotropy (1.1 to 1.21). Finally, we conducted aquifer tests in different wells in the study area to quantify the aquifer parameters. This study offers a strong scientific basis for the assessment of groundwater potential zones and their management in the complex basaltic terrains of the Deccan province.

Rare earth elements (REEs) are effective tracers of groundwater circulation and water-rock interaction in carbonate aquifers. This study investigates hydrochemical parameters and REE compositions of spring waters from Chongqing (eastern Sichuan Basin) to clarify controls on REE mobilization, fractionation, and redox behavior within a fold-controlled karst aquifer. Spring waters exhibit slightly acidic to slightly alkaline pH values (6.2-8.4) and variable redox conditions (Eh from -338 to 148 mV). Hydrochemical facies evolve from Ca-HCO3 and Ca·Mg-SO4 types to Na-Cl and Na-SO4 types, indicating a transition from shallow recharge systems to deeper, structurally controlled groundwater circulation. Total dissolved REE concentrations (ΣREE) range from 0.025 to 1.732 μg/L and show clear spatial variability, with relatively higher values occurring in structurally complex southeastern zones. Correlation analysis indicates that ΣREE concentrations are weakly related to salinity but are influenced by temperature, redox conditions, and bicarbonate availability, reflecting the importance of groundwater circulation depth and water-rock interaction. NASC-normalized REE patterns consistently display LREE depletion and relative MREE-HREE enrichment, typical of carbonate aquifers. Predominantly, Eu anomalies suggest localized reducing or thermally influenced environments associated with deeper groundwater circulation. REE behavior in Chongqing spring waters is indirectly controlled by tectonic structure through its regulation of groundwater circulation and hydrochemical conditions.

The expansion and intensification of agriculture in the Argentine Pampas have increased pesticide use, raising concerns about groundwater contamination in aquifers used for drinking water. In this context, contamination risk assessment is a key tool for environmental management, although results may vary depending on the methodology applied. This study compares two approaches for assessing pesticide-related groundwater contamination risk in the Quequén Grande River watershed (Argentina). Risk was defined as the interaction between aquifer contamination hazard and population vulnerability. Hazard was estimated by combining aquifer vulnerability (DRASTIC-P) with two representations of contaminant load: (i) a land-use-based approach derived from LANDSAT imagery, and (ii) an empirical model based on pesticide leaching experiments relating mobility to soil organic matter. Social vulnerability was assessed using a census-based index. All analyses were conducted within a GIS framework. Results show that the two approaches produce markedly different spatial risk patterns. These differences were evaluated through methodological comparison and preliminary field evidence, but not through a comprehensive independent basin-wide validation. The land-use-based method identified a larger proportion of high-risk areas (20.1%), whereas the laboratory-based approach yielded more restrictive estimates (9.4%) and greater spatial differentiation. These differences reflect the conceptual assumptions underlying each method. The results highlight that method selection strongly influences risk assessment outcomes and should be aligned with management objectives, data availability, and acceptable levels of uncertainty.

The migration of a CO2 plume within saline aquifers and the assessment of CO2 storage capacity are critical factors influencing the implementation of CO2 geological storage engineering and the evaluation of its safety. Previous research has highlighted that the characteristics of gas-water two-phase flow significantly restrict multiphase CO2 flow simulations and the dynamic prediction of reserves. However, the variations in CO2 plume migration, reservoir pressure accumulation, and the dynamic prediction of sealed reservesspecifically under the influence of distinct gas-water relative permeability curves in low-porosity and low-permeability heterogeneous reservoirsremain insufficiently explored. To address this gap, this study employs the Tough/Petrasim simulation tool to develop a CO2 geological storage model for the Liujiagou Formation in the Yulin area of the Ordos Basin. Various gas-water relative permeability models are utilized to investigate the differences in plume migration, pressure accumulation, and reserve evaluation under their influence, while also assessing the applicability of these models. Additionally, the analysis examines the effect of residual water saturation on CO2 migration and storage capacity, elucidating the influence of key storage parameters on CO2 storage effectiveness in the saline aquifers of the study area. The findings are summarized as follows: (1) The model demonstrates that CO2 storage in saline aquifers is highly dependent on the permeability function, which affects plume migration, pressure accumulation, and storage volume by influencing the effective duration and transformation of CO2 storage. While the permeability function is the primary determinant, residual water saturation serves as a significant supplementary factor. (2) Overall, residual water saturation is advantageous; however, elevated saturation levels lead to increased pressure accumulation, posing potential risks to storage projects. (3) The relative permeability function exerts the most substantial influence on CO2 storage capacity, with variations in reserve predictions evident in the supercritical gas storage capacity of both free and residual CO2, although its impact on dissolution states is limited. (4) Predictions using the VG function are more conservative compared to those derived from the Corey and linear functions, particularly in low-porosity and low-permeability heterogeneous environments.

Groundwater is among the planet's most essential natural resources and a crucial part of the global freshwater cycle. It also harbours a specialized aquatic fauna, the stygofauna, which plays a pivotal role in subterranean ecosystem functioning. DNA metabarcoding provides a powerful tool to better uncover the previously largely hidden aquifer communities. It does so by circumventing taxonomic impediments and uncovering cryptic species, simultaneously enabling the assessment of the impacts of pollution and climate change. However, the application of (e)DNA metabarcoding for groundwater metazoans is hindered by two major obstacles: the scarcity of validated primer pairs and the limited taxonomic coverage of reference databases. In this study, we sought to strengthen the molecular toolbox for groundwater biodiversity research by tackling these two challenges. We demonstrate that the primer pair fwhF2 / fwhR2n, targeting the mitochondrial COI region, provides the most effective amplification of central European groundwater invertebrates, particularly crustaceans. In addition, we contributed targeted updates to public databases (for this study assembled in the Groundwater invertebrate Database; GwinD), particularly for 30 Copepoda, five Bathynellacea, and five Ostracoda species. The toolbox was applied in a case study, demonstrating its utility for (e)DNA metabarcoding of central European groundwater communities while highlighting persisting limitations for several non-crustacean groups.

Groundwater occurrence in hard-rock terrains is complex and spatially heterogeneous, controlled by weathered and fractured zones with limited surface expression. This research integrates Vertical Electrical Sounding (VES) with remote sensing, GIS and Analytical Hierarchy Process (AHP) for groundwater potential mapping of Jeypore Block, Koraput District, Odisha. This area is underlain by Eastern Ghats Mobile Belt rocks such as khondalites, charnockites, and granite gneisses. Fifteen VES surveys using Schlumberger configuration were conducted across the study area, with electrode spreads up to 800 m. Resistivity data were interpreted using IPI2WIN software, producing one-dimensional resistivity models and Dar-Zarrouk parameters. Subsurface profiling revealed distinct lithological layers consisting of topsoil, laterite, sandstone, weathered/fractured granite, and compact bedrock. Layer thicknesses ranged from 0.6 to 20.4 m in the first layer to 99.5 m in the third layer. Iso-resistivity maps generated using Surfer-25 showed significant lateral heterogeneity. Low-resistivity zones (2.6-105.2 Ωm) indicated saturated formations, whereas high-resistivity values (> 150 Ωm) represented compact basement rocks. Curve-type analysis identified predominantly AAA-type curves, which indicate increasing resistivity with depth. HA-type curves observed at two locations suggested the presence of conductive, water-saturated layers favourable for aquifer development. VES-derived parameters were integrated with twelve geospatial thematic layers, including geology, geomorphology, soil, NDVI, lineament density, drainage density, rainfall, slope, physiography, land use, groundwater fluctuation, and hydrogeology, using the AHP framework. The consistency ratio of the model was 2.36%, indicating reliable thematic weighting. Validation via pumping tests and ROC analysis (AUC = 0.86) confirmed model reliability. This approach offers a scientifically robust framework for sustainable groundwater management in structurally complex hard-rock terrains.

Acute lymphoblastic leukemia (ALL) is the leading cause of death in Mexican children, yet water-mediated environmental pathways remain largely unexplored as contributors to its spatial distribution. We analyzed ALL mortality records for individuals aged 0-19 years across all Mexican municipalities from 2003 to 2023, using publicly available national death statistics and population estimates. Age-specific mortality rates were calculated at the municipal level and aggregated to the state level to characterize broad geographic gradients. A discrete Poisson spatial scan statistic, implemented in SaTScan, identified 10 statistically significant mortality clusters, five with elevated risk and five with reduced risk, which were then compared against hydrogeological and industrial variables derived from global remote sensing and infrastructure databases. The national mortality rate averaged 1.64 per 100,000 children aged 0-19, with state-level rates ranging more than two-fold from 1.01 in Durango to 2.35 in Tabasco. High-mortality clusters are concentrated along the Gulf of Mexico coast and southeastern states; low-mortality zones lie predominantly in the arid west and northwest. High-mortality areas are systematically characterized by greater annual precipitation, lower aridity, permeable sedimentary geology, and higher forest cover-landscape conditions that collectively maximize infiltration and groundwater contamination risk. All five high-mortality clusters spatially overlap with oil and gas infrastructure, with three coinciding with zones of intensive extraction along the Gulf coast. These findings suggest that groundwater vulnerability and industrial contamination, rather than genetic predisposition, are primary spatial determinants of childhood ALL mortality in Mexico, pointing toward preventable, structurally driven disease burden. Childhood leukemia is the leading cancer among Mexican children, with death rates particularly high in some regions. While better treatments have helped more diagnosed children survive leukemia, we still don't know what in the environment is causing so many children to get sick in the first place. This study mapped where children are dying from leukemia across Mexico to see if patterns emerge. We analyzed data at a detailed geographic scale to avoid missing important local patterns that broader averages might hide. We found that areas with the most deaths tend to get more rain, sit on rock types that let water seep through easily, and have more forest cover, conditions that could help pollution spread through water systems like rivers and aquifers to which vulnerable children may be exposed. Many of these high‐risk areas also have a strong presence of oil and gas operations, which can release cancer‐causing chemicals. Our findings suggest that contaminated water may be an important and underappreciated reason why leukemia kills so many children in certain parts of Mexico. If confirmed, this would mean that a significant share of these deaths could be prevented by focusing prevention efforts where environmental risks are highest, not just treating the disease after it occurs.

In-situ leaching of sandstone-type uranium deposits is frequently constrained by permeability impairment due to pore throat clogging. This issue not only hinders uranium recovery efficiency but also escalates the environmental risk of radioactive nuclide mobilization into surrounding aquifers. Currently, the relative contributions of chemical dissolution limitations and pore-permeability evolution to leaching efficiency remain poorly understood and lack a systematic quantitative evaluation. Herein, a multi-scale experimental framework comparing powder and column leaching was constructed. By introducing a physical mass-transfer efficiency factor (β) and integrating Visual MINTEQ thermodynamic simulations, the mechanisms of precipitation-induced clogging during water-rock interactions were systematically analyzed. Results demonstrate significant variability in the capacity of different lixiviants to mitigate mass-transfer resistance. Citric acid exhibited the highest efficiency, whereas EDDS demonstrated the lowest. Inorganic salt systems, while primarily driven by chemical oxidation, are prone to the precipitation of amorphous colloids (e.g., iron hydroxides). This triggers pore throat clogging and inhibits permeability enhancement, thereby increasing the risk of radioactive nuclide sequestration in the subsurface. Low-molecular-weight organic acids synergistically integrate pore-permeability optimization with efficient chemical complexation, enabling effective mobilization of radioactive nuclides. However, oxalic acid systems are susceptible to localized clogging due to secondary calcium oxalate precipitation. While synthetic chelating agents exhibit strong targeted extraction capacity, they struggle to degrade the rigid quartz-rich mineral framework, leading to significant reductions in leaching efficiency due to physical blockage. These findings provide a theoretical basis for elucidating the pore-clogging mechanisms governed by water-rock interactions and offer scientific guidance for optimizing ISL processes to maximize uranium recovery.

Muddy coastal aquifer subject to seawater (saltwater) intrusion suffer from severe freshwater scarcity and fragile groundwater environments. Traditional groundwater water quality evaluation frameworks relying merely on drinking water standards often categorize high-salinity groundwater (total dissolved solids, TDS > 3 g/L) as low-quality resources, while neglecting their exploitable value for diversified functional applications. To fill this research gap, this study proposes a salinity-based Function-Adaptive Weight Water Quality Index (FAWQI) for targeted, multi-functional groundwater quality assessment. Based on salinity thresholds, groundwater bodies are categorized into three functional types: low-salinity water (3-10 g/L) applicable to livestock breeding, medium-salinity water (10-35 g/L) fit for aquaculture, and high-salinity water (>35 g/L) that can serve as liquid mineral raw materials. Hydrochemical evaluation results indicate that freshwater zones are generally of fair quality, with 27% of samples rated "good" and 43% rated "fair." Brackish groundwater quality is largely restricted by saltwater intrusion and elevated nitrate, which severely restricts its applicability for farmland irrigation. Approximately 52% of low-salinity groundwater samples is acceptable for livestock use, and medium-salinity water consistently meets the standard thresholds for marine aquaculture. Though hypersaline brines are unsuitable for conventional purposes, more than 76% of brine samples are enriched in K+, Na+, Mg2+ Br- and I-, demonstrating great exploitation potential as industrial mineral resources. The proposed FAWQI framework transforms conventional groundwater assessment dominated by single drinking-water-oriented standards into a function-driven classification framework. This novel evaluation method provides robust scientific support for zoned groundwater management and sustainable exploitation of water and mineral resources in saline coastal areas with severe water scarcity.

A long-term environmental programme (OPE) was set up in 2007 by the French National Radioactive Waste Management Agency as a research tool observing simultaneously various environmental compartments in the north-eastern part of France. Since 2012, six continuous water quality monitoring stations created by the OPE assess the variability in time and space of the water quality of three rivers flowing in limestone catchments with distinct impacts of groundwater/surface interactions. We developed a novel approach to estimate sensor measurement uncertainty at the six OPE river stations by calculating the 90th percentile of differences between monthly quality controls and in situ sensor readings. Performances under controlled and real conditions were also compared, showing that this method based on percentiles 90 using ongoing quality controls is more realistic than uncertainty evaluations carried out under controlled conditions. This is partly because it takes into account real conditions over a hydrological year (temperature, flow of watercourses, interferences, etc.) as well as long-term deployment conditions (biofouling). The measurement uncertainty in real time is a prerequisite to avoid over-interpreting variations that are within the measurement uncertainty and thus identify significant trends over time. After accounting for uncertainty, the variability of conductivity, dissolved oxygen, and pH measured using sensor measurements in these rivers during 14 years could be analysed confidently. This in turn allowed us to interpret differences in the impacts of groundwater-surface interactions on river composition and confirm the extent and variability of dissolved oxygen depletion in these rivers.

Many households in gold-mining regions of northern Tanzania have limited access to safe and reliable drinking water and rely on surface water, groundwater, and locally caught fish as key drinking-water and dietary sources, yet the radiological safety of these sources remains uncertain. This study evaluated age-dependent radiological risks from ingestion of naturally occurring radionuclides (234U, 238U, 226Ra, 210Po, 210Pb) in multiple water sources and in fish tissues (bones, gills and flesh) of African lungfish (Protopterus aethiopicus), Nile tilapia (Oreochromis niloticus) and African Catfish (Clarias gariepinus). Activity concentrations were determined by radiochemical separation followed by alpha spectrometry and gas-flow proportional counting. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) were estimated using age-specific water and fish consumption rates. Groundwater, particularly from shallow wells, produced the highest exposures, with a maximum AED for a 5-year-old child, dominated by 234U, exceeding both the World Health Organization (WHO) screening level (0.1&#x202f;mSv/y) and the International Commission on Radiological Protection (ICRP) public dose reference level (1 mSv/y). Fish consumption was the dominant pathway, with African lungfish consistently yielding the highest AEDs, followed by Tilapia and Catfish. The dose contributions were dominated by 210Pb (75% -96%) and 210Po (4% - 25%), while 234U, 238U, and 226Ra contributed <1%. The estimated ELCRs associated with consumption of all fish species, exceeded the USEPA acceptable risk range (10-6 - 10-4). Elevated 234U/238U activity ratios (>1) indicated preferential mobilisation of 234U via alpha-recoil, while low 210Po/210Pb ratios (<1) confirmed 210Pb predominance. These findings underscore the need for continued radiological monitoring and targeted mitigation to protect vulnerable communities.

Groundwater is a vital resource for drinking water supply, agriculture, and industrial activities. However, contamination by organic pollutants may pose significant threats to both ecosystem integrity and human health. This study assessed the environmental and human health risks associated with polycyclic aromatic hydrocarbons (PAHs) in groundwater collected from 27 localities in the central-northeastern Romanian Plain. The concentrations of naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene, and indeno [1,2,3-cd]pyrene were determined using high-performance liquid chromatography coupled with fluorescence detection. Benzo[a]pyrene concentrations ranged from <LOD to 0.08 ng/L, while total concentrations varied between 2.56 to 11.2 ng/L. The environmental risk associated with groundwater contamination was classified as low to moderate, with total risk coefficients ranged from 0.2 to 2.3. Potential contamination sources were identified using the diagnostic ratio method, complemented by multivariate statistical analysis, indicating predominantly pyrogenic and mixed pyrogenic-petrogenic sources. Human health risk assessment indicated that groundwater ingestion posed neither non-carcinogenic risks (Hazard Index, HI < 1) nor unacceptable carcinogenic risks. The Incremental Lifetime Cancer Risk (ILCR) values ranged from 5.7 &#xd7; 10-9 to 2.2 &#xd7; 10-8 for infants, 2.7 &#xd7; 10-9 to 1.0 &#xd7; 10-8 for children, and 1.5 &#xd7; 10-9 to 6.1 &#xd7; 10-9 for adults.

Groundwater is a principal drinking-water source in Mainpur Block, a tribal region of Gariaband District, Chhattisgarh, India, where evidence on heavy-metal exposure and health risks remains limited. Groundwater samples collected from community drinking-water sources during 2023-2025 were analysed for Zn, Fe, Pb, Cr, Mn, and Cd using atomic absorption spectrophotometry. The contamination was evaluated using Heavy Metal Pollution Index, Heavy Metal Evaluation Index, Degree of Contamination, and Metal Index, while health risks for adults and children were estimated, and spatial interpolation was used to identify priority hotspots. Pb and Cd were the major contaminants, with 79% and 86% of 2023 samples, respectively, exceeding the permissible limits prescribed by BIS IS 10500:2012, with maximum concentrations 33 and 9 times the respective limits. The average Heavy Metal Pollution Index was 486, and 83% of the sites were highly polluted. Mean hazard indices were 2.58 for adults and 6.71 for children; 62 of 63 scenarios of child exposure exceeded the safety threshold (HI&#x2009;>&#x2009;1). Screening-level lifetime carcinogenic risk exceeded the de minimis benchmark (10-4) at 95% of locations. Principal component analysis associated Pb-Cd-Mn with anthropogenic influences and Fe-Cr with possible geogenic controls. Eighteen composite hotspots were identified for priority intervention. These findings support targeted groundwater monitoring, drinking-water safety planning, and mitigation in groundwater-dependent tribal communities.

Chlorinated and non-chlorinated aromatic contaminants frequently co-occur in groundwater, but their synergistic bioremediation is often hindered by conflicting redox requirements, microbial niche competition, and the need for external organic carbon sources. Here, we present an electro-stimulated bio-circulation well (ES-BCW) that couples electrode-mediated redox regulation with internal hydraulic recirculation, enabling the simultaneous continuous reductive dechlorination and oxidative aromatic degradation without exogenous organic carbon supplementation. Under continuous operation (120 d), the ES-BCW system achieved average removal rates of 53.2 &#xb5;mol L-1 d-1 for 1,2,4-trichlorobenzene (1,2,4-TCB) and 169.5 &#xb5;mol L-1 d-1 for toluene, respectively, demonstrating competitive performance for anaerobic co-treatment of mixed aromatic contaminants. Optimal weak electrical stimulation (1.2 V) with a controlled reflux (50%) promoted spatial niche differentiation between cathodic reductive and anodic oxidative zones. Microbial analysis revealed selective enrichment of dechlorinating (Dechloromonas and Sphingobium), toluene-degrading (Azoarcus and Thauera), and electroactive (Geobacter and Sulfurospirillum) genera. Integrated metagenomic and metabolomic analyses revealed coordinated enrichment of dechlorination (pcpB, pcpC) and toluene oxidation (bssABC, bbsG) genes, coupled with increased abundances of energy carriers and key electron transfer components (i.e. cytochromes). These shifts collectively supported enhanced electron flux redistribution, metabolic synergy, and sustained acetate cycling, establishing a self-amplifying loop of endogenous carbon reuse that enabled redox partitioning between cathodic reductive and anodic oxidative niches. The ES-BCW system offers an endogenous carbon-driven strategy for synergistic bioremediation of mixed aromatic contaminated oligotrophic groundwater.

Rapid uranium removal from acidic wastewater is significant for nuclear pollution treatment. Robust mechanical strength is necessary for practical applications. Herein, we design a "reinforced concrete" structural aerogel (NWs/SP-CSSB gel) with directional channels via nanowire-assisted directional freezing. Benefiting from interconnected microchannels and hydrophilic ligands, the gel has ultrafast water permeability. Owing to the padding of ultralong nanowires (HAP NWs), the mechanical strength of the gel increased 70.43 times compared with that without NWs. Most uranium is removed within 2 min, and the removal ratio reaches equilibrium within 30 min in the highly acidic environment of pH 3. Meanwhile, it can reduce U to 9.75 ppb from the contaminated groundwater, achieving the drinking water discharge standard. Furthermore, the gel possesses good anti-interference performance, even in a high-salt environment and the presence of interfering ions, including lanthanides, radioelements, and transition metal ions; the U removal ratios of NWs/SP-CSSB gel still maintain 84-96%. The adsorption mechanisms are carefully analyzed by using contrast experiments, kinetic and isotherm models, as well as FTIR and XPS spectra. Considering the high-performance properties and simple fabrication of NWs/SP-CSSB gel, we believe it has great potential in the application of radioactive wastewater treatment.