Groundwater for Sustainable Development最新文献

{"title":"Falling from the ceiling: first evidence of microplastic and microfibre pollution in cave dripping waters","authors":"Valentina Balestra,&nbsp;Raffaella Mossotti,&nbsp;Luca Zini,&nbsp;Rossana Bellopede","doi":"10.1016/j.gsd.2026.101669","DOIUrl":"10.1016/j.gsd.2026.101669","url":null,"abstract":"<div><div>Microplastic (MP) pollution is a global environmental concern. Recent works highlighted the need to consider even natural and regenerated microfibres (MFs). Despite their ecological and hydrological importance, karst systems remain understudied. Being open systems, karst underground environments are particularly vulnerable to contamination through the connections with surface habitats. For the first time, this preliminary research investigated the presence of MPs and other anthropogenic microparticles (AMPs), such as MFs, in cave dripping waters, highlighting the indirect impact of surface human activity. AMPs were counted and characterized via microscopy and spectroscopy. The 80.5% of the analyzed AMPs were cellulosic and 81.6% fibres. MPs ranged from 0 to 23 MP/L, confirming the presence of polyethylene terephthalate (PET) and polyurethane (PU), and were all fragments, except for one PET fibre. Microparticles &lt; 1 mm were the most abundant (89.3%), of which the most had size between 0.49 and 0.10 mm (51.5%). Pollution sources in cave dripping waters could be linked to landfills in sinkholes, garbage, nearby roads, railways, and human activities. These results highlight MPs and other AMP pollution exists in cave dripping waters, impacting water resources, habitats and species. More comprehensive and multidisciplinary monitoring are needed, taking into account surface and subterranean connections in karst areas, aiming at conservation purposes. Promoting collaborations with show caves and cavers can be instrumental in pilot studies, and acquiring new and valuable data.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"34 ","pages":"Article 101669"},"PeriodicalIF":5.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148729885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sustainable wastewater management in the Middle East: Energy recovery and aquifer recharge solutions","authors":"Filippo Verre,&nbsp;Narendra Kumar,&nbsp;Vishal Kumar Parida","doi":"10.1016/j.gsd.2026.101671","DOIUrl":"10.1016/j.gsd.2026.101671","url":null,"abstract":"<div><div>Integrating wastewater treatment with energy recovery and aquifer recharge provides a pragmatic approach to alleviating water scarcity while reducing energy consumption and emissions. Across the Middle East, utilities are pairing treatment trains with biogas and heat recovery, and channeling fit-for-purpose effluent into groundwater replenishment strategies that improve water security and stabilize declining aquifers through managed aquifer recharge (MAR). Widely applied options include Aquifer Storage, Transfer, and Recovery (ASTR/ARR), which leverages subsurface residence time for additional polishing at a low carbon cost, and Soil Aquifer Treatment (SAT), where tertiary effluent percolates through infiltration basins and the vadose zone removes pathogens and organics. Cities are also capturing rooftop rainwater into sand-filled soak pits and sumps to boost local recharge. The region's reuse potential remains vast: roughly half of municipal wastewater is still discharged or evaporated, yet mobilizing this resource could irrigate and fertilize an estimated 1.4 to 2 million hectares (Mha), easing pressure on freshwater and reducing the need for desalination. Realizing that potential requires coherent regulation that sets clear, application-specific quality standards, especially for agriculture, alongside bankable financing models, tariff and incentive designs, and sustained public engagement to build trust and acceptance. With these enablers in place, integrated wastewater-energy-recharge strategies can enhance water security, reduce environmental footprints, and foster long-term urban and agricultural resilience across the Middle East and North Africa (MENA) region.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"34 ","pages":"Article 101671"},"PeriodicalIF":5.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148729880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isotope-geochemical characteristics of groundwater in the southern part of Western Siberia and factors controlling uranium mobilization","authors":"D.A. Novikov,&nbsp;A.N. Pyryaev,&nbsp;F.F. Dultsev,&nbsp;L.G. Vakulenko,&nbsp;N.I. Yandola,&nbsp;A.A. Khvashevskaya,&nbsp;Y.V. Fomina","doi":"10.1016/j.gsd.2026.101674","DOIUrl":"10.1016/j.gsd.2026.101674","url":null,"abstract":"<div><div>This study presents integrated isotope-geochemical data on groundwater from the southern part of Western Siberia to identify the factors of uranium mobilization. Groundwater within the multi-aged, complex rock aquifer system is predominantly of HCO₃–Mg–Ca type, whereas waters hosted in granitoid units (the Priobsky and Barlak complexes) exhibit SO₄–HCO₃–Na–Mg–Ca characteristics. Measured ²²²Rn activity ranges from 1 to 1161 Bq/L. This study systematically evaluated the disequilibrium state of uranium isotopes (²³⁴U/²³⁸U) across contrasting hydrogeological settings: granitoid massifs, contact zones, and sedimentary complexes of different ages. Maximum ²³⁴U excess occurs in granitoid-hosted groundwater, confirming the Priobsky and Barlak complexes as the primary uranium sources in the region. Stable isotope signatures (δ²H, δ¹⁸O) confirm the meteoric origin of the groundwater, with recharge of the Paleozoic bedrock aquifer complex being unaffected by short-term seasonal variations. Thermodynamic modeling classifies all studied waters as a single geochemical type: siliceous-Na (Ca–Mg–K). Elevated uranium concentrations are directly linked to granitoid lithologies hosting accessory minerals (e.g., uraninite, monazite, zircon, bastnäsite) that accumulate uranium, thorium, and rare earth elements. Radionuclides are released into groundwater as a result of mineral weathering. Under oxidizing conditions, uranium remains mobile in the form of uranyl ion (UO₂²⁺), whereas thorium is immobilized via adsorption onto mineral surfaces or precipitation. Subsequent uranium precipitation at redox boundaries may contribute to the formation of paleovalley-type infiltration uranium deposits. These findings advance the understanding of uranium mobilization pathways and support targeted assessments of groundwater safety and mineral potential in crystalline terrains.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"34 ","pages":"Article 101674"},"PeriodicalIF":5.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148730337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Testing water banking recovery policies to secure drought water supply in semi-arid areas with a changing climate","authors":"Peter Dillon,&nbsp;Bridget R. Scanlon,&nbsp;Rebecca Bernat,&nbsp;Dennis Gonzalez,&nbsp;Constantin Seidl,&nbsp;Declan Page,&nbsp;Rebecca Doble,&nbsp;John Radcliffe,&nbsp;Adam Hutchinson,&nbsp;Sharon B. Megdal","doi":"10.1016/j.gsd.2026.101661","DOIUrl":"10.1016/j.gsd.2026.101661","url":null,"abstract":"<div><div>Groundwater storage in many semi-arid areas is diminishing due to declining and more variable recharge. Managed aquifer recharge including water banking offers a potential response to sustain groundwater supplies. The effectiveness of this approach depends critically on how recovery credits are defined. A review of current recovery credit arrangements reveals that storage retention is currently not included in credit specifications for any jurisdiction. Storage retention depends on local hydrogeology and is often poorly defined. This paper applies a simple water balance equation to climate-driven sequences of water recharged to and recovered from a water bank. Two fundamental parameters, maximum recovery entitlement (anthropogenic) and storage retention (hydrogeological), are used to test drought-response performance of one conceptual and four historical managed aquifer recharge and water banking schemes in Australia and USA. These case studies have records of up to 67 years and all exhibit climatic change. They are used to illustrate the impact of the two parameters that could potentially be used to manage recovery credit, in securing future groundwater supplies. Results demonstrate the significant, but not always failsafe, ability of water banking to secure drought supplies under a non-stationary climate. These examples show that aquifer water retention characteristics, that are site-specific and currently rarely quantified, are very important for effective siting and operation of water banks for long-term groundwater security. Many of the reviewed jurisdictions prescribe a time limit of very few years in which a storage credit can be recovered, and thereby remove the incentive for banking water to buffer inevitable future drought. Where losses from an aquifer become desirable gains for streams, publicly funded water banking has distinct advantages over private water banking that focus on only the retained storage credits. Case studies demonstrate water banking potential under climate change at locations where aquifers have high storage retention.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"34 ","pages":"Article 101661"},"PeriodicalIF":5.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148640372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic controls of phosphate and sediment heterogeneity on arsenic fate in karst aquifers: Experimental and modeling insights using a two-site kinetic attachment model","authors":"Song Wei ,&nbsp;Huimei Shan ,&nbsp;Yong Zhang ,&nbsp;Hongbin Zhan ,&nbsp;Hailing Du","doi":"10.1016/j.gsd.2026.101576","DOIUrl":"10.1016/j.gsd.2026.101576","url":null,"abstract":"<div><div>Phosphate (PO₄³⁻) influencing arsenic (As) transport in groundwater has been deeply studied, but quantitative simulation for their co-transport and interactions under the complex heterogeneous conditions characteristic of karst aquifers remains poorly understood. To bridge the critical gap, this study designed column experiments by embedding the natural sediments collected from the karst wetland (presented as lenses, and the number was designed to be 0, 1, and 2) into sand columns. Solutions containing various concentrations of PO₄³⁻ and As were simultaneously pumped into heterogeneous columns and then eluted, and the effluent solutions were regularly collected to monitor their concentrations and the changes in As species within 108 days. The obtained 3-cycle of adsorption-desorption data were quantitatively analyzed using the two-site kinetic attachment model (TSKAM). Key results indicate that (1) The competitive adsorption of PO₄³⁻ significantly enhanced As transport ability. When the PO₄³⁻ concentration increased from 0 to 10 mg/L, the As breakthrough time decreased markedly, with the maximum difference reduced from 16.3 d to 1.0 d in the 1-lens column. Correspondingly, the total As adsorption rate declined from 4.1 h⁻¹ to 2.7 h⁻¹, and the maximum adsorption capacity dropped from 10.1 μg/g to 0.8 μg/g (2) Simultaneously, increasing PO₄³⁻ concentration promoted the reduction of As(V) to As(III), leading to a higher proportion of As(III) in the effluent. The As(III)/Total As ratio increased from 2.63 % to 4.44 % (0-lens), from 6.70 % to 10.05 % (1-lens), and from 8.48 % to 11.74 % (2-lens columns), respectively. (3) Lenticular bodies retarded As mobility through additional adsorption sites, but high PO₄³⁻ levels counteracted this effect. (4) Significant As release from the solid phase occurred during elution stages, with a theoretical constraint (<span><math><mrow><mfrac><msub><mi>k</mi><mn>1</mn></msub><msub><mi>k</mi><mrow><mn>1</mn><mi>d</mi></mrow></msub></mfrac><mo>≥</mo><mfrac><msub><mi>M</mi><mi>e</mi></msub><mrow><mi>P</mi><mi>V</mi><mo>·</mo><msub><mi>C</mi><mrow><mi>S</mi><mi>F</mi></mrow></msub></mrow></mfrac><mo>−</mo><mn>1</mn></mrow></math></span>) for the reversible adsorption/desorption rate derived from TSKAM, where most of the fitted parameters satisfied this relationship (excluding tailing scenarios). These findings elucidate synergistic controls of PO₄³⁻ concentration and sediment heterogeneity on As migration in karst aquifers, providing practical strategies for regional As pollution mitigation.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101576"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Groundwater pollution and sustainable development goals: A crucial resource for achieving sustainable environment","authors":"Rakesh Kumar ,&nbsp;Prabhakar Sharma ,&nbsp;Jasmeet Lamba ,&nbsp;Manish Kumar ,&nbsp;Maria Aurora Armienta ,&nbsp;Tom van der Voorn ,&nbsp;Prosun Bhattacharya","doi":"10.1016/j.gsd.2026.101623","DOIUrl":"10.1016/j.gsd.2026.101623","url":null,"abstract":"","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101623"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147850120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced characterization of fouling in reverse osmosis membrane: Implications for Brackish groundwater treatment","authors":"Ilham Karmal ,&nbsp;Jamila El Gaayda ,&nbsp;Sara Darbal ,&nbsp;Mustapha Nassiri ,&nbsp;Mohamed El Housse ,&nbsp;M’barek Belattar ,&nbsp;Said Ben-Aazza ,&nbsp;Naima Hafid ,&nbsp;Abdelaziz Ait Addi ,&nbsp;Rachid Ait Akbour ,&nbsp;Ali Driouiche","doi":"10.1016/j.gsd.2026.101596","DOIUrl":"10.1016/j.gsd.2026.101596","url":null,"abstract":"<div><div>Growing global freshwater scarcity and the increasing demand for sustainable desalination have stimulated research into reverse osmosis (RO) processes. However, scaling remains a major challenge that affects operational stability and system performance. This study investigates scaling mechanisms in an RO demineralization plant located in El Ouatia, Morocco. A comprehensive approach combining feedwater characterization and hydrochemical analysis was adopted. Fouling was further examined using advanced characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared X-ray spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS), X-ray fluorescence spectrometry (XRF), thermogravimetric and differential scanning calorimetric analysis (TG/DSC), and the Fujiwara test. Physicochemical analyses revealed highly mineralized groundwater, with elevated calcium (998 mg. L⁻¹) and sulfate (3050 mg. L⁻¹) concentrations, which promote mineral precipitation and membrane scaling. Hydrochemical diagrams (Piper, Schoeller-Berkaloff, and Gibbs) indicate that the dominant water chemical facies is of the Na-Cl type. Fouling deposits were found to be primarily composed of gypsum (CaSO₄.2H₂O), accounting for 90.20% of the total deposits and contributing significantly to membrane fouling. Based on these findings, a scaling mechanism is proposed, focusing on interactions among ionic species and fouling processes. These results provide a mechanistic understanding that supports pretreatment strategies and the application of scale inhibitors, thereby improving membrane efficiency in environmental and engineering applications.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101596"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rethinking managed aquifer recharge in karst systems: A novel framework for future directions","authors":"N. Itani ,&nbsp;M. El Fadel","doi":"10.1016/j.gsd.2026.101590","DOIUrl":"10.1016/j.gsd.2026.101590","url":null,"abstract":"<div><div>Managed aquifer recharge (MAR) in karst aquifers presents opportunity, complexity and high uncertainty given their dual-porosity and subsurface complexity, which increases the risk of rapid transport and limited attenuation. This study presents a systematic literature analysis of MAR in karst, synthesizing existing efforts and identifying key challenges and research directions. Water quality concerns, particularly clogging, salinity, aquifer dissolution, and transfer of contaminants to groundwater are among the most persistent limitations. Advances in computational capabilities and remote sensing support numerical models and site suitability assessments while advances in subsurface characterization, a key challenge in karst, are enabled with modern geophysical investigations, tracer tests, and isotope fingerprinting. Future perspectives emphasize transforming the experience from controversial high-risk applications into a mature standard component within integrated water resources management that couples advanced geophysical technologies, machine learning algorithms, surface and subsurface modeling, risk assessment, and adaptable decision-support tools. Practical implications are condensed into a karst-specific, adaptive, and novel framework with an actionable guide for feasible MAR implementation.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101590"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LSTM-based projection of groundwater-induced land subsidence under CMIP6 climate scenarios: A case study of Yunlin, Taiwan","authors":"Sumriti Ranjan Patra,&nbsp;Hone-Jay Chu,&nbsp;Mohammad Adil Aman","doi":"10.1016/j.gsd.2026.101588","DOIUrl":"10.1016/j.gsd.2026.101588","url":null,"abstract":"<div><div>Land subsidence is usually driven by excessive groundwater extraction and further intensified by climate variability. Monitoring land subsidence and projecting its future trends are foundational for sustainable groundwater and subsidence management. This study develops a deep learning-based framework to project future land subsidence in Yunlin County, a major subsidence hotspot within the Choushui River Alluvial Fan in Central Taiwan, under CMIP6 climate change scenarios. A Long Short-Term Memory (LSTM) model is employed to estimate future subsidence rates from 2022 to 2036 by using deep learning-driven groundwater level projections under SSP scenarios. The model is trained using historical groundwater level and multi-level compaction well data from 2015 to 2021. The proposed model accurately estimates land subsidence associated with groundwater level variations, achieving low RMSE (&lt;0.4 cm), NRMSE (&lt;0.1), MAE (&lt;0.3 cm) and high R² (∼0.8) as well as correlation (R) (∼0.9) values. Projections reveal pronounced spatial heterogeneity in future subsidence, with coastal and central regions showing heightened vulnerability. Under SSP245 and SSP585 scenarios, subsidence rates could accelerate historical averages by 1.5-2 cm/year in agricultural-intensive regions, driven by elevated temperatures, declining precipitation causing increased pumping demand, thereby, intensifying groundwater decline. Pronounced effects are further observed for the higher emission SSP585 scenario. Additionally, artificial subsidence mitigation scenarios simulating 10-20 % reductions in groundwater extraction demonstrate the model's effectiveness in assessing intervention strategies, showing a 16-50 % drop in simulated compaction. This research demonstrates the compounding impacts of climate change on groundwater-induced subsidence and emphasizes the effectiveness of deep learning in spatio-temporal forecasting, offering critical insights for adaptive groundwater management and subsidence risk mitigation in regions facing coupled climatic and anthropogenic stressors.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101588"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-isotopic evaluation of hydraulic barriers and water rights in mine tailing impoundments with altitude-offset water sources","authors":"Dídac Navarro-Ciurana ,&nbsp;Laura Culí ,&nbsp;Clara Torrentó ,&nbsp;Neus Otero ,&nbsp;Nicolás Iturra ,&nbsp;Albert Soler","doi":"10.1016/j.gsd.2026.101581","DOIUrl":"10.1016/j.gsd.2026.101581","url":null,"abstract":"<div><div>Sustainable water management in porphyry copper tailings storage facilities (TSFs) is essential for environmental protection and regulatory compliance, particularly in Chile, which ranks third globally in TSF numbers. This study applies a multi-isotope framework (<em>δ</em>²H-H₂O, <em>δ</em>¹⁸O-H₂O<em>, δ</em>³⁴S-SO₄²⁻ and <em>δ</em>¹⁸O-SO₄²⁻) to trace the fate of tailings seepage towards groundwater and to evaluate hydraulic barriers effectiveness in porphyry Cu TSFs, demonstrating its applicability to systems characterized by complex mixing of multiple water sources with contrasting recharge conditions. Unlike previous studies where water sources shared similar recharge altitudes, this work addresses an “altitude-offset” scenario in which tailings water originates from high-altitude recharge zones while downstream aquifers are located at much lower elevations, creating additional isotopic end-members. To illustrate the usefulness of this approach, the Carén TSF (Chile) serves as case study. Isotopic data indicate that tailings waters are strongly evaporated, enriched in elevated SO₄²⁻ concentrations on the order of thousands of mg L⁻¹ (≈2,000 mg L⁻¹), mainly derived from sulfide ore oxidation (60–80 %), and recharged at high altitude (∼2,000 masl). In contrast, surrounding freshwater is recharged at lower altitude (∼220 masl) and shows significantly lower SO₄²⁻ concentrations on the order of tens of mg L⁻¹ (≈20 mg L⁻¹). Groundwater downstream of the TSF reflects variable mixing between these sources. Using Cl⁻/SO₄²⁻, <em>δ</em>²H-H₂O/<em>δ</em>¹⁸O-H₂O, <em>δ</em>³⁴S-SO₄^2-/<em>δ</em>¹⁸O-SO₄^2- and <em>δ</em>³⁴S-SO₄^2-/ln(SO₄²⁻) mixing models, the contribution of mine tailing water was quantified to be generally lower than 20 % but reaching 30–40 % in some groundwater samples located close to the TSF. In addition, <em>δ</em>³⁴S-SO₄^2- and <em>δ</em>¹⁸O-SO₄^2- results suggest that bacterial sulfate reduction may occur in deeper zones of the TSF, promoting natural attenuation of dissolved metals. These findings highlight the usefulness of stable isotopes for tracing water sources, assessing hydraulic barrier efficiency, and estimating the proportion of pumped water exempt from water rights in TSFs.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"33 ","pages":"Article 101581"},"PeriodicalIF":4.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}