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Keywords = formation waters collected

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27 pages, 9975 KiB  
Article
Study on the Hydrogeological Characteristics of Roof Limestone Aquifers After Mining Damage in Karst Mining Areas
by Xianzhi Shi, Guosheng Xu, Ziwei Qian and Weiqiang Zhang
Water 2025, 17(15), 2264; https://doi.org/10.3390/w17152264 - 30 Jul 2025
Viewed by 232
Abstract
To study hydrogeological characteristics after the occurrence of abnormal water bursts from the weak water-rich (permeable) aquifer of the Changxing Formation limestone overlying deep working faces during production in Guizhou karst landform mining areas, hydrogeological data covering the exploration and production periods of [...] Read more.
To study hydrogeological characteristics after the occurrence of abnormal water bursts from the weak water-rich (permeable) aquifer of the Changxing Formation limestone overlying deep working faces during production in Guizhou karst landform mining areas, hydrogeological data covering the exploration and production periods of the Xinhua mining region in Jinsha County, Guizhou Province, were collected. On the basis of surface and underground drilling, geophysical exploration techniques, empirical equations, and indoor material simulation methods, the hydrogeological evolution characteristics of the Changxing Formation limestone in the mining region after mining damage to coalbed 9 were studied. The research results indicated that the ratio of the height of the roof failure fracture zone (as obtained via numerical simulation and ground borehole detection) to the mining height exceeded 25.78, which is far greater than the empirical model calculation values (from 13.0 to 15.8). After mining the underlying coalbed 9, an abnormal water-rich area developed in the Changxing Formation limestone, and mining damage fractures led to the connection of the original dissolution fissures and karst caves within the limestone, resulting in the weak water-rich (permeable) aquifer of the Changxing Formation limestone becoming a strong water-rich (permeable) aquifer, which served as the water source for mine water bursts. Over time, after mining damage occurrence, the voids in the Changxing Formation limestone were gradually filled with various substances, yielding water storage space and connectivity decreases. The specific yield decreased with an increasing water burst time and interval after the cessation of mining in the supply area, and the correlation coefficient R was 0.964, indicating a high degree of correlation between the two parameters. Full article
(This article belongs to the Section Hydrogeology)
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13 pages, 1606 KiB  
Article
The Correlation of Microscopic Particle Components and Prediction of the Compressive Strength of Fly-Ash-Based Bubble Lightweight Soil
by Yaqiang Shi, Hao Li, Hongzhao Li, Zhiming Yuan, Wenjun Zhang, Like Niu and Xu Zhang
Buildings 2025, 15(15), 2674; https://doi.org/10.3390/buildings15152674 - 29 Jul 2025
Viewed by 174
Abstract
Fly-ash-based bubble lightweight soil is widely used due to its environmental friendliness, load reduction, ease of construction, and low costs. In this study, 41 sets of 28 d compressive strength data on lightweight soils with different water–cement ratios, blowing agent dosages, and fly [...] Read more.
Fly-ash-based bubble lightweight soil is widely used due to its environmental friendliness, load reduction, ease of construction, and low costs. In this study, 41 sets of 28 d compressive strength data on lightweight soils with different water–cement ratios, blowing agent dosages, and fly ash dosages were collected through a literature search and indoor tests. Using the compressive strength index and SEM tests, the correlation between the mix ratio design and the microscopic particle components was investigated. The findings were as follows: carbonation reactions occurred in lightweight soil during the maintenance process, and the particles were spherical; increasing the dosage of blowing agent increased the soil’s porosity and pore diameter, leading to the formation of through-holes and reducing the compressive strength and mobility; increasing the fly ash dosage and water–cement ratio increased the soil’s mobility but reduced its compressive strength; and the strength decreased significantly when the fly ash dosage was more than 16% (e.g., the strength at a 20% dosage was 17.8% lower than that at a 15% dosage). Feature importance analysis showed that the water–cement ratio (57.7%), fly ash dosage (30.9%), and blowing agent dosage (11.1%) had a significant effect on strength. ExtraTrees, LightGBM, and Bayesian-optimized Random Forest models were used for 28d strength prediction with coefficients of determination (R2) of 0.695, 0.731, and 0.794, respectively. The Bayesian-optimized Random Forest model performed optimally in terms of the mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE), and the prediction performance was best. The accuracy of the model is expected to be further improved with expansions in the database. A 28 d compressive strength prediction platform for fly-ash-based bubble lightweight soil was ultimately developed, providing a convenient tool for researchers and engineers to predict material properties and mix ratios. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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25 pages, 5705 KiB  
Article
Application of Array Imaging Algorithms for Water Holdup Measurement in Gas–Water Two-Phase Flow Within Horizontal Wells
by Haimin Guo, Ao Li, Yongtuo Sun, Liangliang Yu, Wenfeng Peng, Mingyu Ouyang, Dudu Wang and Yuqing Guo
Sensors 2025, 25(15), 4557; https://doi.org/10.3390/s25154557 - 23 Jul 2025
Viewed by 233
Abstract
Gas–water two-phase flow in horizontal and inclined wells is significantly influenced by gravitational forces and spatial asymmetry around the wellbore, resulting in complex and variable flow patterns. Accurate measurement of water holdup is essential for analyzing phase distribution and understanding multiphase flow behavior. [...] Read more.
Gas–water two-phase flow in horizontal and inclined wells is significantly influenced by gravitational forces and spatial asymmetry around the wellbore, resulting in complex and variable flow patterns. Accurate measurement of water holdup is essential for analyzing phase distribution and understanding multiphase flow behavior. Water holdup imaging provides a valuable means for visualizing the spatial distribution and proportion of gas and water phases within the wellbore. In this study, air and tap water were used to simulate downhole gas and formation water, respectively. An array capacitance arraay tool (CAT) was employed to measure water holdup under varying total flow rates and water cuts in a horizontal well experimental setup. A total of 228 datasets were collected, and the measurements were processed in MATLAB (2020 version) using three interpolation algorithms: simple linear interpolation, inverse distance interpolation, and Lagrangian nonlinear interpolation. Water holdup across the wellbore cross-section was also calculated using arithmetic averaging and integration methods. The results obtained from the three imaging algorithms were compared with these reference values to evaluate accuracy and visualize imaging performance. The CAT demonstrated reliable measurement capabilities under low- to medium-flow conditions, accurately capturing fluid distribution. For stratified flow regimes, the linear interpolation algorithm provided the clearest depiction of the gas–water interface. Under low- to medium-flow rates with high water content, both inverse distance and Lagrangian methods produced more refined images of phase distribution. In dispersed flow conditions, the Lagrangian nonlinear interpolation algorithm delivered the highest accuracy, effectively capturing subtle variations within the complex flow field. Full article
(This article belongs to the Section Chemical Sensors)
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17 pages, 5533 KiB  
Article
Spatial Distribution and Genesis of Fluoride in Groundwater, Qingshui River Plain, China
by Mengnan Zhang, Jiang Wei, Xiaoyan Wang, Tao Ma, Fucheng Li, Jiutan Liu and Zongjun Gao
Water 2025, 17(14), 2134; https://doi.org/10.3390/w17142134 - 17 Jul 2025
Viewed by 228
Abstract
Groundwater in the Qingshui River Plain of southern Ningxia is one of the main water sources for local domestic and agricultural use. However, due to the geological background of the area, 33.94% of the groundwater samples had fluoride concentrations that exceeded the WHO [...] Read more.
Groundwater in the Qingshui River Plain of southern Ningxia is one of the main water sources for local domestic and agricultural use. However, due to the geological background of the area, 33.94% of the groundwater samples had fluoride concentrations that exceeded the WHO drinking water standards. To examine the spatial patterns and formation processes of fluoride in groundwater, researchers gathered 79 rock samples, 2618 soil samples, 21 sediment samples, 138 groundwater samples, and 82 surface water samples across the southern Qingshui River Plain. The collected data were analyzed using statistical approaches and hydrogeochemical diagrams. The findings reveal that fluoride levels in groundwater exhibit a gradual increase from the eastern, western, and southern peripheral sloping plains toward the central valley plain. Vertically, higher fluoride concentrations are found within 100 m of depth. Over a ten-year period, fluoride concentrations have shown minimal variation. Fluoride-rich rocks, unconsolidated sediments, and soils are the primary sources of fluoride in groundwater. The primary mechanisms governing high-fluoride groundwater formation are rock weathering and evaporative concentration, whereas cation exchange adsorption promotes fluoride (F) mobilization into the aquifer. Additional sources of fluoride ions include leaching of fluoride-rich sediments during atmospheric precipitation infiltration and recharge from fluoride-rich surface water. Full article
(This article belongs to the Topic Human Impact on Groundwater Environment, 2nd Edition)
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17 pages, 2670 KiB  
Article
The Influence of Some Physicochemical Parameters of Surface Waters on the Formation of Trihalomethanes During the Drinking Water Treatment Process
by Alexandra Scarlat (Matei), Cristina Modrogan, Magdalena Bosomoiu and Oanamari Daniela Orbuleț
Molecules 2025, 30(14), 2983; https://doi.org/10.3390/molecules30142983 - 16 Jul 2025
Viewed by 314
Abstract
Trihalomethanes (THMs) are a class of disinfectant by-products present in chlorinated tap water. Mainly due to their carcinogenic potential, their concentration in drinking water is now limited by regulations. In Romania, little is known about their distribution in urban drinking water supply systems, [...] Read more.
Trihalomethanes (THMs) are a class of disinfectant by-products present in chlorinated tap water. Mainly due to their carcinogenic potential, their concentration in drinking water is now limited by regulations. In Romania, little is known about their distribution in urban drinking water supply systems, their magnitude, or their seasonal variation. Drinking water suppliers periodically adapt and optimise their water treatment methods for economic reasons and in response to regulatory changes and technological developments. The formation of THMs is influenced by the physicochemical parameters of water (pH, temperature, total organic carbon—TOC) and by environmental factors (geographical, climatological). Most of these factors have significant seasonal variations that lead to the formation of THMs in variable concentrations. In this study, we analysed the seasonal trends in surface water quality (considering variations in temperature, pH, and TOC) and correlated them with the concentration of THMs in drinking water over two calendar years. Water samples were collected from the Arges River, in a geographical area comprised of plains. The results show that the formation of THMs is enhanced by increasing temperature over the course of a year, with the highest concentrations being obtained in July 2022 (98.7 µg/L THMs at 30.5 °C) and in August 2023 (81.9 µg/L THMs at 30.4 °C). The main parameters that trigger the formation of THMs are the organic matter content and the disinfectant dose; the pH has a moderate effect, and its effect is correlated with the concentration of organic matter. There were noted strong seasonal changes in the concentration of THMs, with the maximum peak being in the middle and late summer and the minimum peak being in winter. This indicates the possibility that the quality of drinking water may change as a result of climate change. In addition, monitoring and chlorination experiments have established that the concentration of THMs is directly proportional with the TOC. Full article
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17 pages, 2222 KiB  
Article
Hydrogeochemical Characteristics and Evolutionary Mechanisms of the Nanping Geothermal Field, Southeastern Hainan Island, China
by Xiaolin Wang, Xiaoxue Yan, Wei Zhang, Bo Ma, Changzhu Liu, Yongpeng Yang, Ruoxi Yuan, Jie Chen and Wencun Su
Sustainability 2025, 17(13), 6189; https://doi.org/10.3390/su17136189 - 5 Jul 2025
Viewed by 474
Abstract
The southeastern Hainan Island boasts abundant hydrothermal resources, most of which are exposed as thermal springs. Analyzing the hydrochemical characteristics, hydrochemical evolutionary mechanisms, and material transition of these resources is significant for their exploitation and utilization. This study investigated the Nanping geothermal field [...] Read more.
The southeastern Hainan Island boasts abundant hydrothermal resources, most of which are exposed as thermal springs. Analyzing the hydrochemical characteristics, hydrochemical evolutionary mechanisms, and material transition of these resources is significant for their exploitation and utilization. This study investigated the Nanping geothermal field in southeastern Hainan Island, using five groups of geothermal water samples collected in 2022, as well as seven groups of geothermal water samples, one group of shallow groundwater samples, and one group of surface water samples taken in 2023. Specifically, this study examined water–rock interactions in the geothermal field using the Gibbs model, ion ratios, chloro-alkaline indices (CAIs), and the sodium adsorption ratio (SAR). Moreover, the mineral transfer process in groundwater was analyzed using inverse hydrogeochemical simulation. The results indicate that in the study area the geothermal water temperatures range from 64 °C to 80 °C, pH values from 8.32 to 8.64, and TDS concentrations from 431 mg/L to 623 mg/L. The primary hydrochemical types of geothermal water in the study area include Cl-Na and Cl·HCO3-Na, suggesting low-temperature, slightly alkaline geothermal water. The hydrochemical components of geothermal water in the study area are primarily affected by water–rock interactions. Besides the dissolution of silicate minerals and halite, cation exchange reactions contribute greatly to the formation of Na+ and K+ in geothermal water. Geothermal water receives recharge from the atmospheric precipitation of the Diaoluo Shan area in the northwest of the study area, with the recharge elevation ranging from 967 to 1115 m. The inverse hydrogeochemical simulation results reveal that during the water–rock interactions, silicate minerals, clay minerals, gypsum, and halite dissolve, while quartz and carbonate minerals precipitate. Additionally, these processes are accompanied by cation exchange reactions dominated by the replacement of Na+ in surrounding rocks by Ca2+ in geothermal water. This study can provide a geological basis for the exploitation, utilization, and management of the Nanping geothermal field. Full article
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16 pages, 4663 KiB  
Article
Geological Conditions and Reservoir Formation Models of Low- to Middle-Rank Coalbed Methane in the Northern Part of the Ningxia Autonomous Region
by Dongsheng Wang, Qiang Xu, Shuai Wang, Quanyun Miao, Zhengguang Zhang, Xiaotao Xu and Hongyu Guo
Processes 2025, 13(7), 2079; https://doi.org/10.3390/pr13072079 - 1 Jul 2025
Viewed by 277
Abstract
The mechanism of low- to middle-rank coal seam gas accumulation in the Baode block on the eastern edge of the Ordos Basin is well understood. However, exploration efforts in the Shizuishan area on the western edge started later, and the current understanding of [...] Read more.
The mechanism of low- to middle-rank coal seam gas accumulation in the Baode block on the eastern edge of the Ordos Basin is well understood. However, exploration efforts in the Shizuishan area on the western edge started later, and the current understanding of enrichment and accumulation rules is unclear. It is important to systematically study enrichment and accumulation, which guide the precise exploration and development of coal seam gas resources in the western wing of the basin. The coal seam collected from the Shizuishan area of Ningxia was taken as the target. Based on drilling, logging, seismic, and CBM (coalbed methane) test data, geological conditions were studied, and factors and reservoir formation modes of CBM enrichment were summarized. The results are as follows. The principal coal-bearing seams in the study area are coal seams No. 2 and No. 3 of the Shanxi Formation and No. 5 and No. 6 of the Taiyuan Formation, with thicknesses exceeding 10 m in the southwest and generally stable thickness across the region, providing favorable conditions for CBM enrichment. Spatial variations in burial depth show stability in the east and south, but notable fluctuations are observed near fault F1 in the west and north. These burial depth patterns are closely linked to coal rank, which increases with depth. Although the southeastern region exhibits a lower coal rank than the northwest, its variation is minimal, reflecting a more uniform thermal evolution. Lithologically, the roof of coal seam No. 6 is mainly composed of dense sandstone in the central and southern areas, indicating a strong sealing capacity conducive to gas preservation. This study employs a system that fuses multi-source geological data for analysis, integrating multi-dimensional data such as drilling, logging, seismic, and CBM testing data. It systematically reveals the gas control mechanism of “tectonic–sedimentary–fluid” trinity coupling in low-gentle slope structural belts, providing a new research paradigm for coalbed methane exploration in complex structural areas. It creatively proposes a three-type CBM accumulation model that includes the following: ① a steep flank tectonic fault escape type (tectonics-dominated); ② an axial tectonic hydrodynamic sealing type (water–tectonics composite); and ③ a gentle flank lithology–hydrodynamic sealing type (lithology–water synergy). This classification system breaks through the traditional binary framework, systematically explaining the spatiotemporal matching relationships of the accumulated elements in different structural positions and establishing quantitative criteria for target area selection. It systematically reveals the key controlling roles of low-gentle slope structural belts and slope belts in coalbed methane enrichment, innovatively proposing a new gentle slope accumulation model defined as “slope control storage, low-structure gas reservoir”. These integrated results highlight the mutual control of structural, thermal, and lithological factors on CBM enrichment and provide critical guidance for future exploration in the Ningxia Autonomous Region. Full article
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11 pages, 3107 KiB  
Article
Comparative Analysis of Reconstitution and Solubility of Two Poly-L-Lactic Acid Fillers for Medical Applications
by Pawel Kubik, Wojciech Gruszczyński and Monika Filipowska
Polymers 2025, 17(13), 1778; https://doi.org/10.3390/polym17131778 - 27 Jun 2025
Viewed by 712
Abstract
Objective: This study aimed to evaluate the reconstitution and solubility characteristics of two injectable poly L-lactic acid (PLLA) formulations, the next-generation injectable PLLA-LASYNPRO™ and a previous-generation PLLA (PLLA-SCA), through in vitro analysis. Methods: The study, conducted from 20 November to 11 December 2024, [...] Read more.
Objective: This study aimed to evaluate the reconstitution and solubility characteristics of two injectable poly L-lactic acid (PLLA) formulations, the next-generation injectable PLLA-LASYNPRO™ and a previous-generation PLLA (PLLA-SCA), through in vitro analysis. Methods: The study, conducted from 20 November to 11 December 2024, involved reconstituting PLLA-LASYNPRO™ in 5 mL saline solution and PLLA-SCA in 8 mL sterile water or saline (as specified in the instructions for use). Reconstitution processes were recorded using a 4K camera, and microscopic and sieve-based analyses were performed at various time points (1–120 min). The study used standardized methods for reconstitution, observation, and sample collection, including a light microscope and micrometric sieves. Results: PLLA-LASYNPRO™ exhibited rapid, uniform reconstitution, resulting in a homogeneous milky-white solution with no foam formation. In contrast, PLLA-SCA showed a two-phase mixture with foam formation, requiring more vigorous shaking. Over time, PLLA-LASYNPRO™ displayed gradual sedimentation, with no foam, while PLLA-SCA showed a progressive increase in foam volume and sedimentation. Microscopic analysis revealed consistent particle morphology, with PLLA-LASYNPRO™ particles being smaller and homogeneous, and PLLA-SCA exhibiting larger, irregular particles prone to aggregation. Sieve analysis showed that PLLA-LASYNPRO™ produced minimal sediment, whereas PLLA-SCA consistently produced sediment on both 71 µm and 200 µm sieves. Conclusions: PLLA-LASYNPRO™ and PLLA-SCA display distinct reconstitution behaviors, with PLLA-LASYNPRO™ showing more consistent characteristics and fewer issues with foam and sedimentation. These differences may impact clinical applications and require consideration in treatment planning. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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31 pages, 3056 KiB  
Review
A Review of Key Challenges and Evaluation of Well Integrity in CO2 Storage: Insights from Texas Potential CCS Fields
by Bassel Eissa, Marshall Watson, Nachiket Arbad, Hossein Emadi, Sugan Thiyagarajan, Abdel Rehman Baig, Abdulrahman Shahin and Mahmoud Abdellatif
Sustainability 2025, 17(13), 5911; https://doi.org/10.3390/su17135911 - 26 Jun 2025
Viewed by 780
Abstract
Increasing concern over climate change has made Carbon Capture and Storage (CCS) an important tool. Operators use deep geologic reservoirs as a form of favorable geological storage for long-term CO2 sequestration. However, the success of CCS hinges on the integrity of wells [...] Read more.
Increasing concern over climate change has made Carbon Capture and Storage (CCS) an important tool. Operators use deep geologic reservoirs as a form of favorable geological storage for long-term CO2 sequestration. However, the success of CCS hinges on the integrity of wells penetrating these formations, particularly legacy wells, which often exhibit significant uncertainties regarding cement tops in the annular space between the casing and formation, especially around or below the primary seal. Misalignment of cement plugs with the primary seal increases the risk of CO2 migrating beyond the seal, potentially creating pathways for fluid flow into upper formations, including underground sources of drinking water (USDW). These wells may not be leaking but might fail to meet the legal requirements of some federal and state agencies such as the Environmental Protection Agency (EPA), Railroad Commission of Texas (RRC), California CalGEM, and Pennsylvania DEP. This review evaluates the impact of CO2 exposure on cement and casing integrity including the fluid transport mechanisms, fracture behaviors, and operational stresses such as cyclic loading. Findings revealed that slow fluid circulation and confining pressure, primarily from overburden stress, promote self-sealing through mineral precipitation and elastic crack closure, enhancing well integrity. Sustained casing pressure can be a good indicator of well integrity status. While full-physics models provide accurate leakage prediction, surrogate models offer faster results as risk assessment tools. Comprehensive data collection on wellbore conditions, cement and casing properties, and environmental factors is essential to enhance predictive models, refine risk assessments, and develop effective remediation strategies for the long-term success of CCS projects. Full article
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28 pages, 5040 KiB  
Article
Formation and Evolution Mechanisms of Geothermal Waters Influenced by Fault Zones and Ancient Lithology in the Yunkai Uplift, Southern China
by Xianxing Huang, Yongjun Zeng, Shan Lu, Guoping Lu, Hao Ou and Beibei Wang
Water 2025, 17(13), 1885; https://doi.org/10.3390/w17131885 - 25 Jun 2025
Viewed by 462
Abstract
Geothermal systems play a crucial role in understanding Earth’s heat dynamics. The Yunkai Uplift in southern China exemplifies a geothermally rich region characterized by ancient lithologies and high heat flow. This study investigates the geochemical characteristics of geothermal waters in the Yunkai Uplift. [...] Read more.
Geothermal systems play a crucial role in understanding Earth’s heat dynamics. The Yunkai Uplift in southern China exemplifies a geothermally rich region characterized by ancient lithologies and high heat flow. This study investigates the geochemical characteristics of geothermal waters in the Yunkai Uplift. Both geothermal and non-thermal water samples were collected along the Xinyi–Lianjiang (XL) Fault Zone and the Cenxi–Luchuan (CL) Fault Zone flanking the core of the Yunkai Mountains. Analytical techniques were applied to examine major ions, trace elements, and dissolved CO2 and H2, as well as isotopic characteristics of O, H, Sr, C, and He in water samples, allowing for an investigation of geothermal reservoir temperatures, circulation depths, and mixing processes. The findings indicate that most geothermal waters are influenced by water–rock interactions primarily dominated by granites. The region’s diverse lithologies, change from ancient Caledonian granites and medium–high-grade metamorphic rocks in the central hinterland (XL Fault Zone) to low-grade metamorphic rocks and sedimentary rocks in the western margin (CL Fault Zone). The chemical compositions of geothermal waters are influenced through mixing contacts between diverse rocks of varying ages, leading to distinct geochemical characteristics. Notably, δ13CCO2 values reveal that while some samples exhibit significant contributions from metamorphic CO2 sources, others are characterized by organic CO2 origins. Regional heat flow results from the upwelling of mantle magma, supplemented by radioactive heat generated from crustal granites. Isotopic evidence from δ2H and δ18O indicates that the geothermal waters originate from atmospheric sources, recharged by precipitation in the northern Yunkai Mountains. After infiltrating to specific depths, meteoric waters are heated to temperatures ranging from about 76.4 °C to 178.5 °C before ascending through the XL and CL Fault Zones under buoyancy forces. During their upward migration, geothermal waters undergo significant mixing with cold groundwater (54–92%) in shallow strata. As part of the western boundary of the Yunkai Uplift, the CL Fault Zone may extend deeper into the crust or even interact with the upper mantle but exhibits weaker hydrothermal activities than the XL Fault Zone. The XL Fault Zone, however, is enriched with highly heat-generating granites, is subjected more to both the thermal and mechanical influences of upwelling mantle magma, resulting in a higher heat flow and tension effect, and is more conducive to the formation of geothermal waters. Our findings underscore the role of geotectonic processes, lithological variation, and fault zone activity in shaping the genesis and evolution of geothermal waters in the Yunkai Uplift. Full article
(This article belongs to the Section Hydrogeology)
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22 pages, 13795 KiB  
Article
The Nucleation and Degradation of Pothole Wetlands by Human-Driven Activities and Climate During the Quaternary in a Semi-Arid Region (Southern Iberian Peninsula)
by A. Jiménez-Bonilla, I. Expósito, F. Gázquez, J. L. Yanes and M. Rodríguez-Rodríguez
Geographies 2025, 5(3), 27; https://doi.org/10.3390/geographies5030027 - 24 Jun 2025
Viewed by 310
Abstract
In this study, we selected a series of pothole wetlands to investigate their nucleation, evolution, and recent anthropogenic degradation in the Alcores Depression (AD), southern Iberian Peninsula, where over 100 closed watersheds containing shallow, ephemeral water bodies up to 2 hm2 have [...] Read more.
In this study, we selected a series of pothole wetlands to investigate their nucleation, evolution, and recent anthropogenic degradation in the Alcores Depression (AD), southern Iberian Peninsula, where over 100 closed watersheds containing shallow, ephemeral water bodies up to 2 hm2 have been identified. We surveyed the regional geological framework, utilized digital elevation models (DEMs), orthophotos, and aerial images since 1956. Moreover, we analyzed precipitation and temperature data in Seville from 1900 to 2024, collected hydrometeorological data since 1990 and modelled the water level evolution from 2002 to 2025 in a representative pothole in the area. Our observations indicate a flooded surface reduction by more than 90% from the 1950s to 2025. Climatic data reveal an increase in annual mean temperatures since 1960 and a sharp decline in annual precipitation since 2000. The AD’s inception due to tectonic isolation during the Quaternary favoured the formation of pothole wetlands in the floodplain. The reduction in the hydroperiod and wetland degradation was primarily due to agricultural expansion since 1950, which followed an increase in groundwater extraction and altered the original topography. Recently, decreased precipitation has exponentially accelerated the degradation and even the complete disappearance of many potholes. This study underscores the fragility of small wetlands in the Mediterranean basin and the critical role of human management in their preservation. Restoring these ecosystems could be a highly effective nature-based solution, especially in semi-arid climates like southern Spain. These prairie potholes are crucial for enhancing groundwater recharge, which is vital for maintaining water availability in regions with limited precipitation. By facilitating rainwater infiltration into the aquifer, recharge potholes increase groundwater levels. Additionally, they capture and store run-off during heavy rainfall, reducing the risk of flooding and soil erosion. Beyond their hydrological functions, these wetlands provide habitats that support biodiversity and promote ecological resilience, reinforcing the need for their protection and recovery. Full article
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14 pages, 1267 KiB  
Article
Shower Biofilms and the Role of Plumbing Materials in Reverse Osmosis Water Networks
by Ratna E. Putri, Johannes Vrouwenvelder and Nadia Farhat
Water 2025, 17(13), 1870; https://doi.org/10.3390/w17131870 - 23 Jun 2025
Viewed by 654
Abstract
Domestic showers are critical points of human exposure to microbial biofilms, which may harbor opportunistic pathogens such as Legionella spp. and nontuberculous Mycobacterium. However, biofilm development in reverse osmosis (RO)-treated drinking water systems remains poorly understood. We tested whether shower plumbing material [...] Read more.
Domestic showers are critical points of human exposure to microbial biofilms, which may harbor opportunistic pathogens such as Legionella spp. and nontuberculous Mycobacterium. However, biofilm development in reverse osmosis (RO)-treated drinking water systems remains poorly understood. We tested whether shower plumbing material (flexible polymer hose versus showerhead with inline polyethersulfone filter) and seasonal water variations influence biofilm community assembly. In a controlled field study, commercial shower systems were deployed in households supplied with RO-treated tap water from the KAUST Seawater Desalination Plant; biofilm samples were collected from hoses and filters over 3–17 months. Flow cytometry and 16S rRNA gene amplicon sequencing characterized microbial abundance, diversity, and taxonomic composition. We found that alpha diversity, measured by observed OTUs, was uniformly low, reflecting ultra-low biomass in RO-treated tap water. Beta diversity analyses revealed clear clustering by material type, with hoses exhibiting greater richness and evenness than filters. Core taxa—Pelomonas, Blastomonas, and Porphyrobacter—dominated both biofilm types, suggesting adaptation to low-nutrient, chlorinated conditions. Overall, our results demonstrate that ultra-low-nutrient RO tap water still supports the formation of material-driven, low-diversity biofilms dominated by oligotrophic taxa, underscoring plumbing-material choice as a critical factor for safeguarding shower water quality. These findings advance our understanding of biofilm ecology in RO-treated systems, informing strategies to mitigate potential health risks in shower water. Full article
(This article belongs to the Section Water and One Health)
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16 pages, 1441 KiB  
Article
Effects of Tricholoma Matsutake-Derived Insoluble Fiber on the Pasting Properties, Structural Characteristics, and In Vitro Digestibility of Rice Flour
by Qin Qiu, Jing Chen, Dafeng Sun, Yongshuai Ma, Yujie Zhong, Junjie Yi, Ming Du, Man Zhou and Tao Wang
Foods 2025, 14(12), 2143; https://doi.org/10.3390/foods14122143 - 19 Jun 2025
Viewed by 482
Abstract
This study explores the effects of Tricholoma matsutake-derived insoluble dietary fiber (TMIDF) on the pasting behavior, structural properties, and in vitro digestibility of rice flour. The incorporation of 5% TMIDF significantly increased the peak viscosity (from 2573.21 to 2814.52 mPa·s) by competitively [...] Read more.
This study explores the effects of Tricholoma matsutake-derived insoluble dietary fiber (TMIDF) on the pasting behavior, structural properties, and in vitro digestibility of rice flour. The incorporation of 5% TMIDF significantly increased the peak viscosity (from 2573.21 to 2814.52 mPa·s) by competitively adsorbing water and forming a dense transient network, while simultaneously reducing the final viscosity (from 1998.27 to 1886.18 mPa·s) by inhibiting amylose recrystallization. Multi-scale structural analyses revealed that TMIDF enhanced V-type crystallinity and limited enzyme access via a porous fibrous matrix. Fourier-transform infrared spectroscopy and low-field nuclear magnetic resonance analyses confirmed that hydrogen bonding and water redistribution were key interaction mechanisms. TMIDF significantly lowered in vitro starch digestibility and increased resistant starch content by 16% (from 14.36% to 30.94%) through synergistic effects, including physical encapsulation of starch granules, formation of enzyme-resistant amylose-lipid complexes, and α-amylase inhibition (31.08%). These results demonstrate that TMIDF possesses a unique multi-tiered modulation mechanism, involving structural optimization, enzyme suppression, and diffusion control, which collectively surpasses the functional performance of conventional plant-derived insoluble dietary fibers. This research establishes a theoretical basis for applying fungal insoluble dietary fibers to develop low glycemic index functional foods, highlighting their dual role in improving processing performance and nutritional quality. Full article
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19 pages, 5664 KiB  
Review
6PPD and 6PPD-Quinone in the Urban Environment: Assessing Exposure Pathways and Human Health Risks
by Stanley Chukwuemeka Ihenetu, Qiao Xu, Li Fang, Muhamed Azeem, Gang Li and Christian Ebere Enyoh
Urban Sci. 2025, 9(6), 228; https://doi.org/10.3390/urbansci9060228 - 16 Jun 2025
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Abstract
In recent years, tires have become a prominent concern for researchers and environmentalists in regard to their potential threat of tire-derived pollutants (TDPs) to human health. Among these pollutants, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its oxidized form, 6PPD-quinone (6PPD-Q), have been of primary interest due [...] Read more.
In recent years, tires have become a prominent concern for researchers and environmentalists in regard to their potential threat of tire-derived pollutants (TDPs) to human health. Among these pollutants, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its oxidized form, 6PPD-quinone (6PPD-Q), have been of primary interest due their ubiquity in urban environments, and their potential negative effects on human health. This review provides a summary of human health implications of TDPs, including 6PPD and 6PPD-Q. For the methodology, datasets were collected from the literature sources, including sources, formations and ecological effects of these pollutants, and pathways of human exposure and public health significance. Urban soils are key for services including carbon storage, water filtration, and nutrient cycling, underpinning urban ecosystem resilience. Soil degradation through compaction, sealing, and pollution, particularly by pollutants from tire wear, destroys these functions, however. These pollutants disturb the soil microbial communities, leading to a loss of diversity, an increase in pathogenic species, and changes in metabolism, which in turn can impact human health by increasing disease transmission and diseases of the respiratory systems. Incorporating green-infrastructure practices can enhance the ecosystem service potentials of urban soils and contribute to sustainable, climate-resilient urban city development. These findings underscore the pressing need for a coordinated international campaign to study chronic health effects and science informed policy frameworks to address this ubiquitous environmental health concern—an issue that crosses urban water quality, environmental justice, and global management of tire pollution. Full article
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27 pages, 12033 KiB  
Article
Unusual Mineralogy of Kimberlites: Alkali Carbonates, Sulfates, and Chlorides Among Groundmass Minerals from Unserpentinized Coherent Kimberlite of the Udachnaya-East Pipe, Siberian Craton
by Alexander V. Golovin
Minerals 2025, 15(6), 586; https://doi.org/10.3390/min15060586 - 30 May 2025
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Abstract
The paper reports the first findings of a series of alkali carbonate, chloride, and sulfate minerals among the usual groundmass kimberlite minerals, such as olivine, phlogopite, monticellite, calcite, spinel-group minerals, perovskite, ilmenite, rutile, and apatite. The sample was collected from an unserpentinized coherent [...] Read more.
The paper reports the first findings of a series of alkali carbonate, chloride, and sulfate minerals among the usual groundmass kimberlite minerals, such as olivine, phlogopite, monticellite, calcite, spinel-group minerals, perovskite, ilmenite, rutile, and apatite. The sample was collected from an unserpentinized coherent kimberlite dyke that crosscuts earlier volcaniclastic kimberlite in the central part of the Udachnaya-East pipe. This rock can be described as primary/original kimberlite that did not interact with external/internal hydrothermal fluids either during its formation or after its crystallization. At least three alkali-rich carbonates have been found, a previously unknown (and perhaps, a new one) Na-, Ca-, K-, and S-rich carbonate with the calculated empirical formula (Na,K)6Ca4(CO3,SO4)7, shortite Na2Ca2(CO3)3, and nyerereite (Na,K)2Ca(CO3)2. Chlorides in this kimberlite are halite NaCl and sylvite KCl, and the sulfate is aphthitalite K3Na(SO4)2. The content of the Na-Ca-K-S-rich carbonate in the rock is ~15 vol %, that of shortite and halite is ≤5 vol % each, and those of sylvite and aphthitalite are ≤1 vol %. All alkali-rich minerals are of late magmatic origin. This follows from that (i) the studied kimberlite does not contain any secondary water-rich minerals of hydrothermal transformation of the rocks, such as serpentine, chlorite or iowaite; and (ii) crystalline inclusions of such usual kimberlite minerals as olivine, phlogopite, monticellite, calcite, spinel, perovskite, and apatite were found within Na-Ca-K-S-rich carbonate and halite. This publication expands the list of minerals of magmatic origin identified in the groundmass of worldwide kimberlites by at least three minerals: Na-Ca-K-S-rich (new?) carbonate, sylvite, and aphthitalite. It is important to note that all alkali carbonates, chlorides, and sulfates are unstable during secondary hydrothermal alterations of kimberlites, and hence, these minerals cannot be found in serpentinized rocks. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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