• pISSN 2305-7068
  • eISSN 2097-7476
  • Indexed by ESCI CABI CAS
  • DOAJ EBSCO ProQuest Scopus GeoRef AJ CNKI
Advanced Search
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Distribution and controlling mechanisms of rare earth elements in geothermal waters of Xiamen, Southeastern China
Shuai-chao Wei, Wei Zhang, Ruo-xi Yuan, Feng Liu, Long Li, Xiao-xue Yan
 doi: 10.26599/JGSE.2026.9280104
Abstract(135) FullText HTML(55) PDF(3)
Abstract:
Rare Earth Elements (REEs) are effective tracers of fluid–rock interaction and fluid mixing in geothermal systems, but their behavior in coastal geothermal waters remains poorly constrained owing to the combined effects of seawater intrusion, high ionic strength, and complex ligand competition. In this study, five geothermal water samples from the Xiamen coastal geothermal system, southeastern China, were characterized by hydrochemical analysis, Post-Archean Australian Shale (PAAS)-normalized REE patterns, anomaly indices, and PHREEQC speciation modeling to constrain the distribution and controls of dissolved REEs. Total dissolved REE concentrations (∑REE) range from 0.044 μg/L to 1.651 μg/L, with higher values in coastal waters than in the inland geothermal end-member. All samples show the fractionation pattern light rare earth elements (LREEs) > Middle Rare Earth Elements (MREEs) > Heavy Rare Earth Elements (HREEs), whereas PAAS-normalized patterns indicate relative HREE enrichment and generally negative Ce anomalies. Eu anomalies vary systematically from positive in the inland geothermal water to weak or absent in coastal waters. Regional comparison suggests that deep water–rock interaction controls the overall REE source and abundance levels, whereas seawater mixing primarily modifies REE fractionation, anomaly signatures, and aqueous speciation. Speciation modeling further shows that REEs in coastal geothermal waters are mainly associated with fluoride-, sulfate-, and carbonate-bearing complexes, whereas carbonate complexes dominate in the inland sample. Overall, REE behavior in the Xiamen system is governed by the coupled effects of water–rock interaction and seawater mixing, providing new insight into REE migration and fractionation in fault-controlled coastal geothermal environments.
Heat transfer performance and dynamic effects of middle-shallow U-tube ground heat exchangers under geological stratification
Chang-zhe Wang, Feng Liu, Li-juan Yuan, Hua-jun Wang
 doi: 10.26599/JGSE.2026.9280101
Abstract(1773) FullText HTML(566) PDF(3)
Abstract:
Previous research has lacked sufficient attention to the heat exchange performance of middle-shallow U-tube ground heat exchangers (GHEs), particularly regarding the impact of vertical lithology heterogeneity. In this study, a heat transfer model of GHEs coupling vertical lithological variations and ground temperature distribution is established, based on field test data of middle-shallow boreholes in Langfang, Hebei Province. The heat transfer characteristics of GHEs within the depth of 200–300 m and their influencing factors are analyzed. Results show that the flow velocity and wall thickness strongly affect the heat transfer of middle-shallow GHEs. Increasing the flow rate helps to enhance heat transfer, but is not conducive to improving energy efficiency of the system due to higher power consumption of circulating pumps. There is an optimal flow rate range of 2–3 m3/h for PE-RT GHEs. Furthermore, reducing the wall thickness from 8 mm to 3 mm can significantly improve the heat transfer per unit depth by 10–12% for PE-RT GHEs. The thermal influence distance (TID) of GHEs exhibits significant lithological differences and seasonal variations along the depth. As the depth increases, the TID in winter and summer exhibits increasing and decreasing trends, respectively. Especially, the TID of sandy layers due to a high thermal conductivity is greater than that of clay layers under the same conditions. For 250–300 m deep GHEs, the maximum TID reaches 5.8 m in winter and 7.3 m in summer, respectively, after running for five years. The heat transfer performance of middle-shallow GHEs has an attenuation risk of up to 33–35% during long-term operation, which can be alleviated using an intermittent operation strategy. The present findings can offer a useful reference for the design and optimization of middle-shallow GHEs in similar geological conditions.
New Insights into Soda Water in Shallow Groundwater of the North China Plain
Bo Gao, Jiang-tao He, Bao-nan He, Yan-jia Chu, Zhen Chen, Ji-chao Sun
 doi: 10.26599/JGSE.2026.9280103
Abstract(2074) FullText HTML(695) PDF(5)
Abstract:
Soda water in shallow aquifers represents a unique hydrochemical type, often enriched in arsenic (As), fluorine (F), iodine (I), and other components, while also acting as a critical driver of soil salinization. However, existing studies have failed to effectively distinguish between salinization (characterized by soluble salt accumulation) and alkalization (characterized by soda-alkali enrichment). The "New Insights" of this study do not rely on new data but derive from an in-depth excavation and interpretation of the 2006–2009 National Groundwater Pollution Survey dataset—the only authoritative background dataset covering the entire North China Plain. Focusing on shallow groundwater in the North China Plain, this study refines the identification criteria for soda water based on existing concepts, analyzes its spatial distribution characteristics, delineates typical zones, and conducts a preliminary investigation into the genetic differences across regions. Results show that when using the criterion—"HCO3 + CO32− as dominant anions with [(HCO3 + CO32−) - (Ca2+ + Mg2+)] > 0 meq%"—combined with hydrochemical cluster analysis, soda water is primarily concentrated in two zones: The mountain-front discharge zone (Area A) and the runoff-ancient Yellow River channel zone (Area B). These two zones account for 88.48% of all soda water samples and exhibit distinct hydrochemical features. In Area A, groundwater has a simple anion composition dominated by HCO3, a median total dissolved solids (TDS) content of 501.15 mg/L, and elevated concentrations of F and NO3. In contrast, Area B is characterized by diverse anions (HCO3, SO42−, and Cl), a higher median TDS (863.56 mg/L), and enrichment of reductive components including As, F, I, Fe, and Mn. Genetic analysis reveals that soda water in Area A forms through the combined effects of mineral weathering, dissolution, and calcite-dolomite precipitation. In contrast, groundwater in Area B evolves under calcite-dolomite precipitation controlled by evaporative concentration, with further modifications by microbial geochemical processes and agricultural activities. This study clarifies the spatial distribution patterns and genetic mechanisms of soda water in the North China Plain, laying a foundation for further research on its formation processes.
Identification of the effects of shallow-buried mining on the hydrochemical evolution of phreatic groundwater in arid and semi-arid regions: A case study of the Ten Tributaries Basin
Zhuang Wang, Jun-nan Li, Ge-su Tao, Chao-zhu Li
 doi: 10.26599/JGSE.2026.9280095
Abstract(1787) FullText HTML(616) PDF(14)
Abstract:
Revealing the evolution of phreatic water hydrochemistry under natural processes and mining activities in shallowly buried mining areas of arid and semi-arid regions is key to identifying the impacts of mining on groundwater. Taking the Ten Tributaries Basin in the upper Yellow River as the study area, this study combined ion ratios, stable isotope tracing, and the Chemical Mass Balance (CMB) model to reveal and quantify the effects of coal mining (recharge area) and mirabilite mining (discharge area) on phreatic water chemistry. Results show that mining activities are the key anthropogenic factor driving the spatial differentiation of phreatic water chemistry, with influence intensity exhibiting significant spatial heterogeneity. In undisturbed areas, natural dissolution processes contribute more than 80% of the hydrochemical composition, dominated by carbonate dissolution. However, in mining-affected areas, groundwater chemistry deviates from natural evolutionary pathways, characterized by enhanced dissolved-ion input and more complex ionic compositions. In recharge areas, coal mining mainly promotes carbonate dissolution and vadose-zone disturbance, increasing TDS by factors of 1.96 and 1.88, respectively, relative to natural conditions. In discharge areas, mirabilite mining is dominated by evaporite dissolution and deep saline-water mixing, leading to TDS increases by the factors of 4.41 and 3.24, respectively. These mining effects are superimposed on the pathway-controlled groundwater flow system, resulting in distinct spatial differentiation of groundwater hydrochemistry. The improved CMB model effectively quantifies the impacts of mining disturbances on groundwater chemistry. The results provide scientific support for groundwater resource management and ecological protection in shallowly buried mining areas of arid and semi-arid regions.
2026,  Issue 3
Research Article
Karst distribution characteristics in a watershed under topographic differentiation and implication for groundwater resource: A case study in Southwest China using ERT and borehole data
Zhan-yu Tang, De-qiu Dai, Wei-wei Jiang, Ren-jian Deng
2026, 14(3): 271-287.   doi: 10.26599/JGSE.2026.9280083
Abstract(0) FullText HTML(0) PDF(0)
Abstract:
Karst landforms are renowned for their unique characteristics, and investigating karst development characteristics is of great significance for groundwater regulation and ecological management. This study aims to interpret karst distribution under different topographic conditions in a watershed using Electrical Resistivity Tomography (ERT). Taking the Chenqi small watershed in Southwest China as the study area, 10 ERT survey lines were deployed across three topographic settings (dip slopes, anti-dip slopes, and high-lying depressions). By combining 2D/3D ERT inversion, geological drilling, and outcrop verification, the subsurface karst distribution was revealed. The results show that ERT effectively detects karst features with high heterogeneity and discontinuity. Conduit-type karst appears in the middle section of both slopes, indicating groundwater migration pathways. Karst water is dominated by runoff on dip slopes, whereas infiltration dominates on anti-dip slopes; continuous low-resistivity aquicludes in high-lying depressions control local groundwater levels. The average karst zone thickness is 2.0–4.0 m, with a maximum of 12 m. These findings demonstrate a coupled relationship between karst structure and groundwater runoff under topographic differentiation, providing a quantitative reference for watershed-scale groundwater processes and practical value for karst water exploration, resource regulation, and slope stability assessment.
Attenuation of hydroclimatic influence on groundwater dynamics under anthropogenic stress: A decadal spatiotemporal analysis in Jaipur, India
Mohammad Imroz, MP Akhtar, Fahad Alshehri
2026, 14(3): 288-306.   doi: 10.26599/JGSE.2026.9280086
Abstract(152) FullText HTML(68) PDF(10)
Abstract:
Groundwater constitutes the primary freshwater resource in semi-arid regions, where low and erratic rainfall combined with high evapotranspiration limit effective recharge. Jaipur, a rapidly expanding metropolitan city in western India, is experiencing increasing groundwater stress due to the combined influence of climatic variability and anthropogenic pressures. While groundwater depletion in Rajasthan is well documented, the extent to which interannual climatic variability, particularly rainfall fluctuations, translates into measurable groundwater-level response in urban fractured hard-rock aquifer systems remains uncertain. This study evaluates groundwater-level dynamics (2013–2023) in relation to climatic variability and examines the apparent decoupling between climatic signals and groundwater response under combined hydrogeological and anthropogenic influences in Jaipur. Groundwater and gridded climatic datasets were analyzed using geospatial mapping, kriging-based spatial interpolation, and correlation-based statistical approaches. Pearson, Spearman, and Kendall correlation methods were employed to assess statistical relationships. Interannual groundwater variations were further analyzed to characterize temporal depletion patterns. In addition, event-based proxy analysis using extreme precipitation indices (R×1d and R×5d) was conducted to evaluate the influence of short-duration and cumulative rainfall events on groundwater response. Results indicate weak and spatially inconsistent relationships between climatic variables and groundwater levels, suggesting that groundwater response cannot be adequately explained by linear climatic relationships alone and is influenced by non-linear and lagged recharge processes. A strong inverse correlation between relative humidity and evapotranspiration (r = −0.9272, p < 0.0001) highlights the dominant role of atmospheric moisture conditions in regulating evapotranspiration fluxes, with implications for reduced effective recharge. These findings suggest that groundwater dynamics in the study area exhibit partial decoupling from climatic variability, likely driven by hydrogeological constraints and sustained anthropogenic pressures. This underscores the importance of adopting integrated groundwater management strategies that account for both climatic variability and anthropogenic pressures.
Multi-scale characterization of karst media, negative-pressure suffusion mechanism and collapse risk assessment for urban metro engineering: A case study of Guiyang metro line 3, China
Lei Zhang, Xiang-quan Li, Jian-fei Ma, Zhen-yuan Zhang, Chang-chang Fu, Chun-chao Zhang, Ce Zhang
2026, 14(3): 307-322.   doi: 10.26599/JGSE.2026.9280084
Abstract(0) FullText HTML(0) PDF(0)
Abstract:
Multi-scale characterization of karst media is a fundamental prerequisite for accurate stability evaluation and collapse risk assessment in karst terrains, especially for the safety control of urban metro engineering. Taking the Huaxi South Parking Lot of Guiyang metro line 3 as a case study, this paper proposes an integrated framework for karst collapse risk assessment by coupling multi-scale geological characterization, hydrodynamic-mechanical coupling simulation, and spatial multi-factor analysis. A comprehensive dataset, including 339 borehole records, core CT scanning results, long-term hydrogeological monitoring data, and laboratory test results, was collected to conduct multi-scale characterization of karst media across macro, meso and micro scales, reveal the vertical zonation of karst structures, clarify the hydrodynamic triggering mechanism of karst collapse, determine the critical instability threshold, and reproduce the entire evolution process of collapse. The results show that negative-pressure suffusion induced by rapid groundwater level decline, with a critical pressure difference of ≤ −190 kPa, is the dominant trigger of karst collapse in the study area. The lowest stratum stability and highest collapse risk occur in the strata with an overburden thickness of 2–5 m and a karst cavity diameter of ≥ 3 m. The high-risk zones account for 2.3% of the total study area, and are mainly distributed in the southern part, while the overall site remains stable under normal hydrodynamic conditions. This study can provide theoretical support and technical reference for karst collapse risk prevention and control in urban metro engineering.
Mechanism of seepage heat transfer in thermal reservoirs of high temperature metamorphic rocks in the Yanggao-Tianzhen basin
Mei-hua Wei, Yan-guang Liu, Xin Wang, Gao-jing Ren, Chao Xu, Jing-wen Liu, Ying-nan Zhang, Xu-cai Zhang
2026, 14(3): 323-341.   doi: 10.26599/JGSE.2026.9280085
Abstract(0) FullText HTML(0) PDF(0)
Abstract:
A typical high-temperature metamorphic rock geothermal reservoir was newly discovered in the Tianzhen geothermal field in Datong City, China. However, due to the complex geological structure and thermal properties, the seepage heat transfer mechanism of metamorphic rock reservoirs is still unclear, seriously impeding the efficient development and sustainable utilization of geothermal resources. This study established a percolation-heat transfer model through tracer testing and numerical simulation to reveal the percolation mode and heat transfer mechanism of high-temperature metamorphic rock reservoirs during the reinjection process. We also predicted the distribution characteristics of various physical fields in the geothermal reservoir after the geothermal system has been in operation for 100 a, analyzed the influence of different reinjection schemes on seepage heat transfer in the geothermal reservoir, and proposed an optimization strategy for the reinjection scheme. The results show that: (1) The connectivity between production and injection wells is poor, and there are water-conducting fractures connecting the shallow and bottom layers; (2) The seepage channels through fractures guide the migration of the reinjected fluid and form a cold front surface with a protruding shape towards the mining well in the temperature field, resulting in temperature changes in the production well; (3) Seepage heat transfer in thermal reservoirs is greatly affected by the reinjection flow rate and the distance between production and reinjection wells, but less by the reinjection temperature. As the reinjection temperature drops, the flow rate increases, the well spacing decreases, and the temperature variation range of the production well becomes greater; (4) Under the current reinjection test conditions, the temperature of the mining well decreased by approximately 4°C after 100 a of geothermal reinjection operation, and a thermal breakthrough occurred at 78 a. Under the condition of maintaining a reinjection flow rate of 60 m3/h and a reinjection temperature of 80°C unchanged, the well spacing should be no less than 470 m to ensure that the well temperature does not cause a thermal breakthrough during the reinjection operation for 100 a. This research provides a theoretical basis and optimization methods for the efficient development of high-temperature metamorphic rock thermal reservoirs.
Groundwater contamination risk from refinery-derived water-soluble fractions: A comprehensive assessment of organic carbon, hydrocarbons, and oxygenated organic compounds
Jiu-hao Song, Wang Yu, Wei Zhou, Jia-yi An, Feng Xiong, Jin-hui Cao, Qi Gao, Yu-ping Zhang, Jian-hui Ma, Jie Ma
2026, 14(3): 356-381.   doi: 10.26599/JGSE.2026.9280087
Abstract(0) FullText HTML(0) PDF(0)
Abstract:
Petroleum products can contaminate groundwater through dissolution of their Water-Soluble Fractions (WSFs), yet the composition and dissolution behavior of WSFs from different refined products remain insufficiently understood. In this study, oil-water equilibrium WSFs of 25 refined petroleum products from the same refinery were generated using a slow-stirring method and analyzed for Total Organic Carbon (TOC), Total Petroleum Hydrocarbons (TPH), Volatile Petroleum Hydrocarbons (VPH), Extractable Petroleum Hydrocarbons (EPH), and Ooxygen-Containing Organic Compounds (OCOCs). The results showed that the dissolved organic concentrations of WSFs varied by 1–2 orders of magnitude among different product types. Gasoline, naphtha, and atmospheric residues produced WSFs with relatively high TOC and TPH concentrations, dominated by C6-C9 aromatic hydrocarbons. In contrast, kerosene, diesel, and most gasoline blending components exhibited much lower dissolved hydrocarbon concentrations. In several gasoline-related products, oxygenated additives such as Methyl Tert-Butyl Ether (MTBE) and Tert-Amyl Methyl Ether (TAME) were detected at high levels and dominated the dissolved organic composition, resulting in elevated OCOCs/TPH ratios. In addition, butane was identified as a characteristic dissolved compound in the WSF of alkylated oil. These results demonstrate pronounced differences in the chemical composition and distribution patterns of dissolved constituents among refined petroleum products.
Comparative evaluation of upscaled analytical and numerical models for DNAPL dissolution processes
Pan-rui Yang, Xiao-min Yuan, Hui-rong Guo, Bao-lan Li, Xing-quan Wang, Min Yuan
2026, 14(3): 382-398.   doi: 10.26599/JGSE.2026.9280088
Abstract(0) FullText HTML(0) PDF(0)
Abstract:
Mathematical model-based accurate evaluation of the remediation process at organic pollution sites serves as an efficient approach to the management and remediation of contaminant source zones. Numerical and upscaled analytical solution models are effective mathematical methods for reproducing the Dense Nonaqueous Phase Liquid (DNAPL) remediation process. However, in the current design of pollutant removal schemes, effective mass transfer models for characterizing the elution behaviors of contaminants remain lacking. In this study, two mathematical methods integrated with improved mass transfer models were employed to simulate the multi-stage contaminant elution behaviors under two distinct scenarios: A mixed-source region subjected to continuous water flushing and a residual DNAPL source treated with shorter-duration pulse flushing of the ethanol solution. Both the improved numerical model and upscaled analytical solution model demonstrated enhanced accuracy, which was attributed to the incorporation of solubilization mechanisms into mass transfer processes and the adoption of a multi-source region division method. The Mean Absolute Errors (MAE) of the numerical simulation for the two scenarios were 20.68 mg/L and 6.93 mg/L, respectively, whereas those of the upscaled model were 33.29 mg/L and 8.60 mg/L, respectively. Comparing the two improved models, the numerical model exhibited higher accuracy, while the upscaled model was characterized by faster computation speed and fewer input parameters.
Review Article
Remediation technologies for heavy metal-contaminated water resources
Samar A El-Mekkawi, Sh K Amin
2026, 14(3): 399-434.   doi: 10.26599/JGSE.2026.9280089
Abstract(133) FullText HTML(57) PDF(1)
Abstract:
Heavy metals, including arsenic, lead, cadmium, chromium, mercury, copper, nickel, and zinc, are common contaminants in global water resources. Their occurrence stems from both natural geogenic and anthropogenic sources, such as industrial, mining, or urban activities. Heavy metals can be found in groundwater due to geogenic mobilization and leaching from ore deposits. They can also be found in streams and lakes impacted by mine drainage, industrial effluents, agricultural runoff, and urban stormwater. Elevated concentrations pose risks to human health and ecosystems, necessitating monitoring, remediation, and the safe management of generated residuals. A variety of technologies exist for heavy-metal removal. The selection and use of these technologies depend on contaminant concentration, speciation, and available resources. In this review article, the latest technologies for heavy-metal removal are presented and discussed. The availability and maturity of each technique, energy demand, management of generated residual, environmental impact, and recommended applications are discussed. Algal bioremediation and constructed wetlands are the most sustainable techniques due to their ecosystem benefits, carbon capture, and lowest energy consumption, while the most efficient industrial techniques are membrane technologies and ion-exchange systems due to their high metal selectivity and purity; however, the main restrictions are high cost and an energy-intensive nature. The most distinctive approach involves hybrid systems, which offer a more resilient and sustainable alternative by integrating complementary mechanisms that enhance flux stability, improve selectivity, and reduce energy consumption, such as the combination of Reverse Osmosis with Membrane Distillation (RO-MD) and Reverse Osmosis with Pressure Retarded Osmosis (RO-PRO). The hybrid approach, in various sequences, enhances efficiency, scalability, and ecological restoration.
1.9
Impact Factor(2025)
3.7
CiteScore 2025
Editor-in-ChiefLI Qing-hua
Sponsors

Institute of Hydrogeology and Environmental Geology (IHEG), CAGS

China Chapter, International Association of Hydrogeologists (IAH-CC)

Commission on Hydrogeology, Geological Society of China(GSC-CH)