Groundwater for Sustainable Development最新文献

{"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":"2026-01-14","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":"Comparative analysis of nitrate sources in surface and groundwater within a karst watershed utilizing nitrogen and oxygen isotopes","authors":"Wei Zhang ,&nbsp;Zhongfa Zhou ,&nbsp;Hui Dong ,&nbsp;Shengjun Ding ,&nbsp;Yong Xiong ,&nbsp;Jijuan Wang ,&nbsp;Yi Huang ,&nbsp;Ye Zhang ,&nbsp;Xiaoduo Wang","doi":"10.1016/j.gsd.2026.101580","DOIUrl":"10.1016/j.gsd.2026.101580","url":null,"abstract":"<div><div>Nitrate pollution seriously threatens water security in karst areas. In these areas, surface water and groundwater systems are highly interconnected, and pollution migration mechanisms are complex. Currently, the spatiotemporal variations of nitrate sources driven by agricultural and tourism activities and their response to seasonal anthropogenic disturbances remain unclear. This study selected the Chiwuxi Basin, a typical karst agricultural-tourism composite watershed in southwestern China, as the study area. Various methods, including hydrochemical analysis, nitrate dual isotopes (δ¹⁵N, δ¹⁸O) tracing, and the Bayesian mixing model (MixSIAR), were used to systematically and quantitatively analyze the sources, transformation processes, and contribution patterns of nitrate in surface water and groundwater. The results indicate that: (1) The average nitrate concentration in groundwater (9.73 mg/L) was significantly higher than that in surface water (6.08 mg/L). This reflects that the “preferential flow” formed by karst fissure-conduit systems promoted the subsurface migration and accumulation of pollutants. (2) Both hydrochemical and isotopic indicators suggest that nitrification is the dominant nitrate transformation process. (3) The MixSIAR model quantitatively reveals that soil nitrogen was the primary source (63.9 % in surface water, 61 % in groundwater). Chemical fertilizer was secondary, with a greater contribution to groundwater (28.2 %) than to surface water (23.5 %). This highlights the importance of agricultural non-point source inputs through subsurface pathways. (4) The contributions of pollution sources showed significant seasonal dynamics. Soil nitrogen dominated in the dry season, while chemical fertilizer and domestic sewage contributed more in the wet season. This pattern responds to agricultural fertilization cycles and variations in tourist flow. This study clarifies the spatiotemporal differentiation mechanisms of nitrate sources and the seasonal regulatory role of human activities in the surface water–groundwater system of karst agricultural-tourism composite watersheds. The findings can provide a scientific basis for implementing coordinated “surface–subsurface” pollution control, precise interception of agricultural non-point source pollution, and enhanced management of seasonal tourism wastewater in such regions.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101580"},"PeriodicalIF":4.9,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977444","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":"Bioaugmented graphene sand composite for manganese and pollutants removal in groundwater","authors":"Nur Raihan Ahmad Nahrawi ,&nbsp;Wei Lun Ang ,&nbsp;Ebrahim Mahmoudi ,&nbsp;Ahmad Razi Othman ,&nbsp;Abdul Wahab Mohammad","doi":"10.1016/j.gsd.2025.101572","DOIUrl":"10.1016/j.gsd.2025.101572","url":null,"abstract":"<div><div>This study evaluates the graphene sand composite (GSC) as both a biofilm supports medium and an adsorbent for removing contaminants from groundwater. GSC synthesized with 10 % sugar molasses achieved a uniform coating and optimal bacterial survivability (6.55 × 10¹¹ CFU/mL), making it highly suitable for microbial attachment. In phase I, GSC promoted early biofilm formation (by day 5) and maintained manganese removal efficiencies consistently above 80 %, outperforming bioaugmented river sand. Phase II evaluated GSC with different bacterial inoculations under real groundwater conditions. Among all configurations, the native strain-inoculated GSC (B2 column) exhibited the most effective performance, achieving 90 % removal of manganese and iron within 24 h and 90 % nitrate removal within 3 h. All GSC columns achieved &gt;90 % tetracycline removal, while pesticide removal ranged between 60 and 70 %. These results highlight GSC's potential ability as a dual functionality to integrate microbial oxidation and adsorption for multi-contaminant removal. The enhanced performance of native bacterial inoculation underscores the importance of strain selection in optimizing bioaugmented filtration systems. GSC offers a scalable and sustainable platform for environmental remediation.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101572"},"PeriodicalIF":4.9,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925651","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":"Assessing groundwater storage response to snow cover dynamics in large Moroccan river basins over the last decades using remote sensing data","authors":"Mostafa Bousbaa ,&nbsp;Abdelghani Boudhar ,&nbsp;Mohammed Hssaisoune ,&nbsp;Haytam Elyoussfi ,&nbsp;Ismail Karaoui ,&nbsp;Bouchra Bargam ,&nbsp;Karima Nifa ,&nbsp;Abdessamad Hadri ,&nbsp;Siham Acharki ,&nbsp;Gemine Vivone ,&nbsp;Christophe Kinnard","doi":"10.1016/j.gsd.2025.101574","DOIUrl":"10.1016/j.gsd.2025.101574","url":null,"abstract":"<div><div>Groundwater reserves face increasing pressure from human activities and climate variability. Increased domestic, industrial, and agricultural demand has led to unsustainable dependence, disrupting natural replenishment, particularly in semi-arid and arid regions. This study examines how snow cover, a key factor in groundwater recharge, influences groundwater reserves in Morocco's main basins, focusing on assessing the relative importance of snowmelt and rainfall. Remote sensing data from MODIS for snow cover area (SCA), the Global Gravity-based Groundwater Product (G3P) for groundwater storage anomalies (GWSA), and the Integrated Multi-satellitE Retrievals for GPM (IMERG) for rainfall were used for this purpose from September 2002 to August 2023. Trend analysis, correlation metrics, and a regression-based framework were used to assess temporal variability and quantify recharge sources. Results showed that G3P-derived GWSA accurately captured groundwater level variations, achieving high correlation (up to 0.93) and low error (as low as 0.72), confirming its reliability. During the study period, most basins showed significant GWSA declines, closely related to decreasing SCA. A 6 to 8-month lag was observed between SCA and GWSA peaks. Furthermore, SCA depletion and GWSA change rates revealed distinct hydrological responses across basins. In Oum Er-Rbia and Draa, their strong correlation highlighted the significant role of snowmelt in groundwater recharge. In contrast, moderate correlations in other basins indicate additional influences. On average, snowmelt contributed 5 %–50 % to groundwater recharge, highlighting its important, yet secondary, role in seasonal snow regions. These results highlight the role of snowmelt in groundwater recharge and the vulnerability of groundwater to variations in snow cover and precipitation. Our results further underscore the need for adaptive water management, particularly in semi-arid and arid regions.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101574"},"PeriodicalIF":4.9,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925653","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":"Impact of coupled climate change and human exploitation on groundwater dynamics in agricultural intensive planting areas","authors":"Jiajun Li ,&nbsp;Bo Li ,&nbsp;Peng Qi ,&nbsp;Zhijun Li ,&nbsp;Yunfei Bai","doi":"10.1016/j.gsd.2025.101575","DOIUrl":"10.1016/j.gsd.2025.101575","url":null,"abstract":"<div><div>Groundwater resources are essential for agricultural production, especially in areas of intensive agricultural. Using western Jilin Province, China, as a case study, this paper systematically evaluates groundwater dynamics under the combined impacts of climate change and human exploitation. Although extensive research has explored the effects of climate change on groundwater systems, the integration of climate models with groundwater-exploitation scenarios remains understudied. Accordingly, we used GMS–MODFLOW to construct a three-dimensional groundwater flow model. Using observed groundwater-level data from 10 observation wells, we simulated the groundwater flow field for 2007–2016 and validated the model. Building on this setup, we conducted scenario-based simulations to project the spatiotemporal dynamics of groundwater levels for 2021–2080, using six Global Climate Models (GCMs) and the four Shared Socioeconomic Pathways (SSPs) (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), and imposing exploitation-rate adjustments of ±20 % relative to current levels. Results show that precipitation accounts for approximately 95 % of total recharge. Across all scenarios, groundwater discharge exceeds recharge, producing a long-term negative change in storage whose magnitude increases under higher-emissions forcing; the mean annual storage deficit rises from 1.20 × 10⁸ m³/yr (SSP1-2.6) to 2.20 × 10⁸ m³/yr (SSP5-8.5). The regional mean groundwater-level decline rate ranges from 1.68 to 3.00 cm/yr, yielding a cumulative drop of 0.98–1.80 m by 2080. However, a 20 % reduction in groundwater exploitation can partially mitigate this trend: relative to the +20 % exploitation scenario, the regional mean decline rate falls by about 50 %, hotspots of serve decline contract markedly, and exploitation-driven spatial heterogeneity is reduced. The analysis further indicates that higher-emissions scenarios exacerbate human impacts on groundwater, whereas lower-emissions scenarios help alleviate these effects. Our distinctive contribution is an integrated modeling framework that tightly couples climate-change projections with groundwater-abstraction scenarios, yielding actionable insights for groundwater management in agricultural regions, informing adaptive pumping strategies, and supporting long-term sustainable use.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101575"},"PeriodicalIF":4.9,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884015","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":"Enrichment characteristics of colloid−bound ammonium and phosphorus in groundwater systems: Insights into their sources and controls","authors":"Shuxin Huang ,&nbsp;Mingjian Gao ,&nbsp;Jiasen Li ,&nbsp;Ruihan Xiong ,&nbsp;Bing Liu ,&nbsp;Hengyi Wang ,&nbsp;Caixiang Zhang","doi":"10.1016/j.gsd.2025.101573","DOIUrl":"10.1016/j.gsd.2025.101573","url":null,"abstract":"<div><div>High levels of colloid−bound ammonium (C−NH₄⁺) and phosphorus (C−P) have been proved to exist in groundwater systems, which can pose a potential threat on human health and ecosystems. However, field−scale studies of their enrichment characteristics remain limited. In this study, high levels of C−NH₄⁺ (up to 19.7 mg/L) and C−P (up to 3.28 mg/L) were found in groundwater systems of Jianghan Plain, China. Among them, C−NH₄⁺ was mainly distributed in small molecular weight fraction (1 − 10 kDa), while C−P was mainly distributed in large and medium molecular weight fraction (10 kDa −0.45 μm). The release of C−NH₄⁺ (up to 105 mg/kg) and C−P (up to 652 mg/kg) from sediments could be a main source of colloids in groundwater. Moreover, correlation and principal component analysis (PCA) results indicated another source of anthropogenic input for C−NH₄⁺ and C−P. Importantly, the enrichment of C−NH₄⁺ was mainly regulated by colloidal Fe/Mn (C−Fe/Mn), whereas that of C−P was coupling controlled with C−Fe/Mn and dissolved organic matter. Fluorescence excitation−emission matrices with parallel factor analysis (EEM−PARAFAC) results revealed the terrestrial humic−like and tryptophan−like components of different colloidal fractions. Large and medium molecular weight C−P (10 kDa−0.45 μm) regulated by terrestrial humic−like dissolved organic matter (DOM) could form complex colloids through surface active sites (DOM−P binary complexes). Small molecular weight C−P (1−10 kDa) was closely related to the degradation or the release of internal proteinaceous substances (e.g., tryptophan) by microorganisms. This study provides new insights into the enrichment of C−NH₄⁺/P in groundwater systems.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101573"},"PeriodicalIF":4.9,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925650","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 hydrochemistry, pollution source analysis, and health risk in western Jilin, China","authors":"Tao Li ,&nbsp;Xinying Cui ,&nbsp;Dongmei Ruan ,&nbsp;Jianmin Bian","doi":"10.1016/j.gsd.2025.101560","DOIUrl":"10.1016/j.gsd.2025.101560","url":null,"abstract":"<div><div>Groundwater (GW) components in western Jilin are shaped by natural geology and anthropogenic activities (particularly water projects), driving groundwater quality (GWQ) variations with health implications. Consequently, effective GW management requires accurate GW information including GWQ, pollution source identification, and human health risk assessment (HHRA).</div><div>This paper presented integrated methods for comprehensive evaluation of these elements. From the GWQ perspective, SNWTM integrated groundwater quality evaluation methods (GWQEM) with TOPSIS to enhance accuracy, method interpretability, and overcome single-method limitations for diverse water samples. To accurately identify GW pollution sources, this study utilized Self-Organizing Map (SOM) and Positive Matrix Factorization (PMF), whose integration provided complete pollution source characterization through combined qualitative-quantitative analysis, enabling targeted identification. In HHRA, this study developed a novel method for selecting the most probable value interval (TMPVI) in trapezoidal fuzzy numbers (TFN) and subsequently integrated with cloud model (CM) and Monte Carlo (MC) to establish TCM, that overcame data limitations and process uncertainty of conventional HHRA including the four-step method (TFM) and triangular stochastic (TSS).</div><div>SNWTM indicated higher GWQ in unconfined water (UW) versus confined water (CW). SOM (4 clusters) and PMF (6 factors) identified a geogenic–anthropogenic interaction, with geogenic Mn and the three-nitrogen species as the dominant contributors (maximum PMF shared 59.76 % and 62.67 %, respectively). TCM indicated that the risk was higher in UW versus CW, and higher for children than for adults. In 2022–2023, the UW-children 95th-percentile output was 1.26, exceeding the risk threshold.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101560"},"PeriodicalIF":4.9,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884014","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":"Evaluation of groundwater management strategies by optimization under land subsidence constraints","authors":"Juan José Díaz-Nigenda ,&nbsp;Eric Morales-Casique ,&nbsp;Mauricio Carrillo-García ,&nbsp;Mario Alberto Vázquez-Peña ,&nbsp;Selene Olea-Olea","doi":"10.1016/j.gsd.2025.101569","DOIUrl":"10.1016/j.gsd.2025.101569","url":null,"abstract":"<div><div>Land subsidence is one of the most critical consequences of groundwater depletion, underscoring the need for management tools capable of evaluating how extraction decisions affect both aquifer conditions and ground deformation. Computational optimization models provide a powerful means to support such decision-making; however, most groundwater management studies addressing subsidence-prone systems impose constraints solely on aquifer drawdown, without explicitly controlling land subsidence. Here we develop an optimization framework that integrates management constraints on both aquifer drawdown and land subsidence rate, enabling simultaneous control of hydraulic conditions and deformation. Three constraint strategies were defined and applied to a simulated aquifer–aquitard system to evaluate the coupled response between aquifer drawdown and aquitard compression. The methodology involved formulating optimization models with alternative constraints, simulating multi-year scenarios, and comparing their impacts on groundwater dynamics and land subsidence behavior. Results demonstrate that the choice of management constraints strongly influences aquifer depletion, aquitard response, and total land subsidence. When only drawdown is constrained, total settlement reaches roughly 10 % of the aquitard thickness. Introducing a subsidence-rate constraint limits settlement to about 1.25 %, while applying only a subsidence-rate constraint reduces settlement to 0.04 % of the aquitard thickness. However, a trade-off would arise between controlling land subsidence and supplying groundwater as the volume of water produced through the management period is also reduced. These outcomes highlight the effectiveness of integrated management constraints and illustrate how integrated constraints can inform groundwater management decisions in subsidence-prone settings.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101569"},"PeriodicalIF":4.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840938","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":"Locating nitrogen sources in high inorganic nitrogen zones of a shallow coastal aquifer using an integrated analytical framework","authors":"Qiaona Huang ,&nbsp;Ya Wang ,&nbsp;Shan Ye ,&nbsp;Bingfa Zhi ,&nbsp;Zhongzhong Wang","doi":"10.1016/j.gsd.2025.101570","DOIUrl":"10.1016/j.gsd.2025.101570","url":null,"abstract":"<div><div>Groundwater nitrogen contamination poses a critical global environmental challenge. To address this significant regional to global scale groundwater challenge, identifying the exact locations of nitrogen sources is essential for pollution source management and control. This study systematically analyzed 83 shallow groundwater samples from Zhuhai through an integrated analytical framework. This framework progressively follows the steps of qualitative identification of inorganic nitrogen pollution sources, spatial identification of pollution hotspots, and delineation of specific spatial boundaries of potential sources, by integrating multiple techniques such as isotopic analysis, hydrochemical characteristics, land use analysis, and hydrogeological features etc., ultimately achieving precise positioning of inorganic nitrogen emissions. Spatial interpolation indicated that elevated inorganic nitrogen predominantly occurred in the densely populated western agricultural and industrial region, where groundwater was highly vulnerable to anthropogenic impacts. Based on the qualitative identification of hotspot nitrogen sources, this study successfully constrained the specific locations of nitrogen sources through land use and groundwater flow field analysis to site scale with limited area. Pollution sites for three NH₄⁺-N hotspots of Zhuhai, which were dominantly influenced by cropland, domestic sewage, and local industrial wastewater were clearly identified. The NO₃⁻-N hotspot's nitrogen source was traced to anthropogenic wastewater within a 100 m radius to the southeast. This study demonstrated the effectiveness of the proposed integrated analytical framework, the results achieved is very convenient for pollution source management and control and could be applied to locate inorganic nitrogen pollution sources in other regions globally.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101570"},"PeriodicalIF":4.9,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840939","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":"Deep and fossil aquifers in Morocco: A multidisciplinary assessment of groundwater dynamics and salinization","authors":"Ayoub Ayaou ,&nbsp;Yassine Ait Brahim ,&nbsp;Mohammed Hssaisoune ,&nbsp;Meryem Miftah ,&nbsp;Ahmed El-Azhari ,&nbsp;Lhoussaine Bouchaou","doi":"10.1016/j.gsd.2025.101566","DOIUrl":"10.1016/j.gsd.2025.101566","url":null,"abstract":"<div><div>In Morocco, groundwater serves as a strategic water resource for drinking, domestic, agriculture, and industrial purposes due to the scarcity of surface water and high vulnerability to climate change. This dependency stems from the arid to semi-arid climate conditions where ecosystems depend on groundwater. Successive droughts, population growth, and economic development, particularly in agriculture, lead to the overexploitation of groundwater, especially shallow aquifers during the three last decades. This situation necessitates an investigation of these deep aquifers to manage this essential resource effectively. Hence, the aim of this study is to provide insights into deep aquifers, including their geometry, hydrodynamic, hydrochemical characteristics, recharge origins, geothermal potential, and residence times to determine which aquifers take longer to recharge and which should remain unexploited. The investigated deep aquifers exhibit a wide range of salinity, with electrical conductivity values ranging from 231 to 49 040 μs/cm, whereas pH values range from 5.64 to 10.76. The high salinity is primarily attributed to Cl⁻, SO₄²⁻, Na⁺ and HCO₃⁻ with average concentrations of 829, 475, 463, and 316 mg/l, respectively. The recharge of the majority studied deep aquifers, particularly the Cretaceous ones (Souss, Essaouira, Ouarzazate, Tadla, Haouz, and Errachidia), is mainly from the High Atlas Mountains, except for the deep aquifers of Sahara where recharge is carried out during a specific context. The deep Jurassic aquifers, including the South Rifain Corridor, High and Middle Moulouya, High Plateaus, Horst Chain, Taourirt-Oujda Corridor, Beni-Bouyahi, and Bni-Znassen aquifers, are recharged from the Middle Atlas and North-Eastern Moroccan Mountains. Most investigated deep aquifers containing old waters are considered fossil or less renewable, with residence times exceeding 20 kiloannum before present (ka BP). The deep Sahara aquifers are the most significant groundwater potential reserves due to their lithologic composition, and their extensive area of approximately 90 000 km², but with very low groundwater replenishment rates dating back over 46.5 ka BP according to radiocarbon dating. Because of their variable mineralization related to their variable geological contexts and human activities, all the investigated systems show a high vulnerability mainly within their outcrops, which are mainly karstic or fissured areas. These deep aquifers require more stringent management and protection due to arid climate and very low precipitation through all the investigated regions. The results provide key information on the functioning of Moroccan deep aquifers and highlight the need for careful management and conservation.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"32 ","pages":"Article 101566"},"PeriodicalIF":4.9,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925649","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}