Water-rock Interaction Research Articles

Chemical and Thermal Changes in Mg3Si2O5 (OH)4 Polymorph Minerals and Importance as an Industrial Material

Serpentine (Mg3Si2O5(OH)4), like quartz, dolomite and magnesite minerals, is a versatile mineral group characterized by silica and magnesium silicate contents with multiple polymorphic phases. Among the phases composed of antigorite, lizardite, and chrysotile, lizardite and chrysotile are the most prevalent phases in the serpentinites studied here. The formation process of serpentinites, which arise from the hydrothermal alteration of peridotites, influences the ratio of light rare earth elements (LREE) to heavy rare earth elements (HREE). In serpentinites, the ratio of light rare earth elements (LREE)/heavy rare earth elements (HREE) provides insights into formation conditions, geochemical evolution, and magmatic processes. The depletion of REE compositions in serpentinites indicates high melting extraction for fore-arc/mantle wedge serpentinites. The studied serpentinites show a depletion in REE concentrations compared to chondrite values, with HREE exhibiting a lesser degree of depletion compared to LREE. The high ΣLREE/ΣHREE ratios of the samples are between 0.16 and 4 ppm. While Ce shows a strong negative anomaly (0.1–12), Eu shows a weak positive anomaly (0.1–0.3). This indicates that fluid interacts significantly with rock during serpentinization, and highly incompatible elements (HIEs) gradually become involved in the serpentinization process. While high REE concentrations indicate mantle wedge serpentinites, REE levels are lower in mid-ocean ridge serpentinites. The enrichment of LREE in the analyzed samples reflects melt/rock interaction with depleted mantle and is consistent with rock–water interaction during serpentinization. The gradual increase in highly incompatible elements (HIEs) suggests that they result from fluid integration into the system and a subduction process. The large differential thermal analysis (DTA) peak at 810–830 °C is an important sign of dehydration, transformation reactions and thermal decomposition, and is compatible with H2O phyllosilicates in the mineral structure losing water at this temperature. In SEM images, chrysotile, which has a fibrous structure, and lizardite, which has a flat appearance, transform into talc as a result of dehydration with increasing temperature. Therefore, the sudden temperature drop observed in DTA graphs is an indicator of crystal form transformation and CO2 loss. In this study, the mineralogical and structural properties and the formation of serpentinites were examined for the first time using thermo-gravimetric analysis methods. In addition, the mineralogical and physical properties of serpentinites can be recommended for industrial use as additives in polymers or in the adsorption of organic pollutants. As a result, the high refractory nature of examined serpentine suggests that it is well-suited for applications involving high temperatures. This includes industries such as metallurgy and steel production, glass manufacturing, ceramic production, and the chemical industry.

The potential water quality impacts of hard-rock lithium mining: Insights from a legacy pegmatite mine in North Carolina, USA

The global green energy transition has spurred increased lithium exploration and extraction, yet the water quality impacts from lithium mining are understudied. This study investigates the potential water quality impacts from a legacy hard-rock lithium mine through comprehensive geochemical analyses of groundwater, surface waters, ore grade rocks, tailings, and waste rocks from a mine site in North Carolina, USA. The concentrations of regulated contaminants (e.g. As, Pb) in both groundwater and surface water emerging from the mine site were low, below drinking water and ecological standards. Yet Li (up to 46.8 mg/L), Rb (up to 169 μg/L), and Cs (up to 21 μg/L) were elevated relative to local background waters. Leaching experiments of the pegmatite ores, waste rocks, and tailing consistently demonstrate low mobilization of regulated contaminants and high leachability of Li, Rb, and Cs. Leaching experiments also reveal that water-rock interactions of the rocks and solid wastes from the mine site generate alkaline conditions, and that both phosphate and spodumene minerals are primary sources of Li and play a major role in formation of alkaline conditions during early stages of water-rock interactions. Over longer time scales, their direct impact on water quality is decreased. Given the global interest in hard-rock lithium mines, our findings highlight the potential occurrence of Li, Rb, and Cs in water resources adjacent to hard-rock lithium mines.

Genesis of the Bailugou Vein-Type Zinc-Lead-Silver Deposit, Eastern Qinling Orogen, China: Constraints from Ore Geology and Fluid Inclusions

The Bailugou vein-type zinc-lead-silver deposit is located in the Eastern Qinling Orogen, China. There has been a long-standing debate about whether its formation is related to magmatism or metamorphism. To determine the origin of ore-forming materials and fluids, we conducted a geological and fluid inclusion investigation of the Bailugou. Field surveys show that the vein-type orebodies are controlled by faults in the dolomitic marbles of the Mesoproterozoic Guandaokou Group, and they are distal to the regional Yanshanian intrusions. Four ore stages, i.e., quartz–pyrite ± sphalerite (Stage 1), quartz–polymetallic sulfides (Stage 2), dolomite–polymetallic sulfides (Stage 3), and calcite (Stage 4), are identified through microscopic observation. The homogenization temperatures of measured fluid inclusions vary in the range of 100 °C to 400 °C, with the dominating concentration at 350 °C to 400 °C, displaying a descending trend from early to late stages. The estimated formation depth of the Bailugou deposit varies from 2 km to 12 km, which is deeper than the metallogenic limit of the epithermal hydrothermal deposit but conforms to the typical characteristics of a fault-controlled deposit. The ore-forming fluid in Stage 1 originates from a fluid mixture and experiences a phase separation (or fluid immiscibility) between the metamorphic-sourced fluid and the fluids associated with ore-bearing carbonate-shale-chert association (CSC) strata. This process results in the transition to metamorphic hydrothermal fluid due to water–rock interactions in Stage 2, culminating in gradual weakening and potential fluid boiling during the mineralization of Stage 3. Collectively, the Bailugou lead-zinc-silver mineralization resembles an orogenic-type deposit formed by metamorphic fluids in the Qinling Yanshanian intracontinental orogeny.

Characteristics and genesis of high-quality metasilicate mineral water in Liaocheng City, Shandong Province.

Drinking natural mineral water often contains minerals and trace elements essential for human beings, such as strontium and silicon. As people's quality of life improves, so do their requirements for drinking water. Therefore, it is crucial to identify and develop high-quality groundwater that is rich in metasilicate and other minerals. The aim of this study is to reveal the distribution pattern and causes of high-quality metasilicate-rich groundwater in Liaocheng City through scientific methods, so as to provide a theoretical basis for the rational development and protection of mineral water resources. The results shown that Dong'e County was the main concentration area of high-quality metasilicate mineral water in Liaocheng City. The main reason for its high concentration of metasilicic acid was due to water-rock interaction. There was bedrock fissure water in the underlying water supply rock groups in Dong'e County, and the reaction between the metasilicate minerals in the rock groups and water was the main source of metasilicic acid. In addition, the development of fissures in the area provided a good storage and conductivity system for the enrichment of metasilicic acid in groundwater. Based on the analysis of hydrogeological conditions and the mechanism of formation of enriched areas, the enriched areas were divided into developable areas, protected and restricted development areas, and restricted development areas. The results of the study can lay a theoretical foundation for the systematic and scientific development, utilization, and protection of high-quality metasilicate mineral water in Liaocheng City.

Feasibility Study on Geothermal Dolomite Reservoir Reinjection with Surface Water in Tianjin, China

Reinjection is thought to be the most effective way to maintain reservoir pressure and production capacity for hydrothermal resources. The use of external water injection to replenish deep geothermal reservoirs is a new approach in China to addressing the problems of declining groundwater levels and energy depletion caused by the excessive and uneven exploitation of geothermal resources. However, the key challenge and focus of the feasibility assessment of this method lies in the chemical compatibility of the external water with the native geothermal reservoir water and surrounding rocks. In this paper, we discuss the geochemical response of a dolomite reservoir to lake water injection based on experiments on water–rock interaction in the Wumishan formation in the Dongli Lake area of Tianjin. The results show that after reactions with dolomite, the TDS of the reacted water decreases, indicating the occurrence of precipitation. According to the calculation results obtained using the PHQREEC program, the precipitation amount is found to be quite limited. Geochemical analysis indicates that at the initial stage of the reactions, plagioclase dissolves and releases alkaline metals like Ca-, Na-, SiO2- and Al-bearing compositions, leading to the oversaturation and precipitation of dolomite and calcite. As the reaction progresses, a portion of the dolomite dissolves, while the calcite continues to precipitate at a later stage. Illite precipitates and its effects on reservoir structure depend on its shape. Based on the experimental data, it can be concluded that the dolomite reservoir will be slightly affected by the reinjection of lake water; however, it is still a good method for the sustainable development of geothermal resources.

Shallow Groundwater Quality Assessment and Pollution Source Apportionment: Case Study in Wujiang District, Suzhou City

Groundwater serves as a crucial resource, with its quality significantly impacted by both natural and human-induced factors. In the highly industrialized and urbanized Yangtze River Delta region, the sources of pollutants in shallow groundwater are more complex, making the identification of groundwater pollution sources a challenging task. In this study, 117 wells in Wujiang District of Suzhou City were sampled, and 16 groundwater quality parameters were analyzed. The fuzzy synthetic evaluation method was used to assess the current status of groundwater pollution in the study area; the principal component analysis (PCA) was employed to discern the anthropogenic and natural variables that influence the quality of shallow groundwater; and the absolute principal component scores–multiple linear regression (APCS-MLR) model was applied to quantify the contributions of various origins toward the selected groundwater quality parameters. The results indicate that the main exceeding indicators of groundwater in Wujiang District are I (28%), NH4-N (18%), and Mn (14%); overall, the groundwater quality is relatively good in the region, with localized heavy pollution: class IV and class V water are mainly concentrated in the southwest of Lili Town, the north of Songling Town, and the south of Qidu Town. Through PCA, five factors contributing to the hydrochemical characteristics of groundwater in Wujiang District were identified: water–rock interaction, surface water–groundwater interaction, sewage discharge from the textile industry, urban domestic sewage discharge, and agricultural non-point source pollution. Additionally, the APCS-MLR model determined that the contributions of the three main pollution sources to groundwater contamination are in the following order: sewage discharge from the textile industry (10.63%) > urban domestic sewage discharge (8.69%) > agricultural non-point source pollution (6.26%).

Calculation model of shale fracture compressibility and evolution of permeability under water-bearing conditions

Water saturation of shale reservoirs significantly influences the permeability and compressibility of propped fractures. This study focused on the Longmaxi Formation shale reservoir in northern Guizhou, China, where the permeability of water–saturated shale under varying gas and confining pressures was measured. A compressibility model for proppant embedment and compaction deformation was developed and validated against the experimental results. This study examined the compressibility of supported fractures considering water–rock interactions and elucidated the intrinsic relationship between compressibility and water saturation. The findings demonstrated a decreased trend in shale fracture permeability with increasing water saturation under identical conditions. Compared to dry shale, the permeability decreased by 1.2%–16.4% and 2.0%–17.8% at water saturation of 15% and 50%, respectively. The results of the model calculations demonstrate that fracture compressibility is contingent on the degree of variation of the fracture width. Prolonged water–rock interactions intensified the variation in the fracture width increasing the compressibility under the same stress conditions. As the water saturation increased from 0% to 50%, the fracture closure rate increased from 0.034 to 0.179 with the increase in effective stress. Increased water saturation also increases the sensitivity of the fracture compressibility to effective stress while decreasing the elastic modulus of the rock, thereby enhancing the proppant embedment depth and significantly increasing the fracture compressibility. This study provides critical insights into the dynamic evolution of fracture permeability during hydraulic fracturing and offers valuable implications for gas production forecasting.

Groundwater quality in Sargodha City, Pakistan: comprehensive research of geochemical modeling, groundwater quality assessment, and risk evaluation

Groundwater, an indispensable global resource, faces escalating contamination threats, jeopardizing human health and environmental sustainability. This study offers detailed insights into the quality of the groundwater, its drinking suitability, and associated human health risks in Sargodha City, Pakistan. Employing hydrogeochemical analysis, inverse geochemical modeling, groundwater quality index, and human health risk evaluation, this research highlights widespread exceedances of WHO drinking water standards, particularly in TDS, EC, TH, Na+, Ca2+, Mg2+, SO42−, Cl−, HCO3−, NO3-N, and As levels, signifying that a significant portion of the groundwater is unfit for consumption. Hydrochemical facies analysis reveals a dominance of the Na-Cl type. Water–rock interactions, cation exchange, and anthropogenic influences are the primary factors shaping groundwater hydrochemistry in the region. Saturation indices and inverse geochemical modeling demonstrated intricate geochemical processes involving both mineral precipitation and dissolution. Notably, the GWQI reveals a diverse spectrum of water quality, with 50% of the samples exhibiting excellent to good quality, 29% falling into the poor to extremely poor category, and 21% deemed unfit for drinking. Health risk assessment reveals alarming carcinogenic risks from As, affecting children (70.8%) and adults (83.35%), while 8.3% of the samples indicate non-carcinogenic risks. Conversely, NO3-N presents acceptable non-carcinogenic risks across all samples. The total hazard index spans between 0.14 and 1.90 for adults and 0.16 to 2.23 for children, underscoring the heightened vulnerability of children. This study advances the understanding of groundwater contamination dynamics in urbanized regions, offering insights to safeguard public health and ensure sustainable water management in areas with similar hydrogeochemical conditions.

Geophysical characterization of the bedrock and regolith in the Pranmati basin critical zone, Uttarakhand Himalaya

The young active Himalayan mountain is characterized by steep slope and dissected topography in overall compressive tectonic setting. The mountain belt has primarily coarse textured soil with poor water holding capacity and is highly prone to erosion. The erosion not only affects many ecosystems located at downstream but also has detrimental effects on the critical zone (CZ). In the present study, we have carried out DC electrical resistivity study in the Pranmati catchment of the Alaknanda basin, a Himalayan critical zone in the Lesser Himalaya, to understand the pattern of soil erosion, transportation and deposition by characterizing the bedrock architecture and hence regolith thickness. A total of 6 electrical resistivity tomogram (ERT) profiles were laid at two locations in the catchment, one in a plain grassland and another at a crop field located on a hill slope of >25o. The study area in the Baijnath klippe, consists of quartz-biotite gneisses with layers of quartz mica-schist enclosed by thrust faults. Electrical resistivity sections of the downslope grassland site show a sharp resistivity contrast between the southwest and northeast transects suggesting south-eastern increase in dip of the bedrock, oblique to the north-east facing surface topography and a thick regolith (> 10 m). The resistivity sections of the site located on the hillslope yield a very thin layer of regolith (< 2 m) indicating significant soil erosion and high weathering of the bedrock. We propose that the water–rock interaction within the porous regolith facilitated by subsurface water circulation might be a potential source for the thick regolith. The observations substantiate existing hypotheses for the evolution and development of deep critical zones. From the results, it has been hypothesized that the bedrock architecture and water channel paths within the CZ together control the regolith thickness.

Using UAVs to collect filtered water samples for mineral exploration: Will it take off?

The advent of unmanned aerial vehicle (UAV) assisted surface water sampling and ongoing technological advances in sampling and data acquisition, offers many opportunities to conduct high-quality hydrogeochemical surveys with low cost, high efficiency, and reduced human interactions. Hydrogeochemical mineral exploration is one area that could greatly benefit from a UAV sampling revolution, with survey sites often located in highly remote areas with limited existing infrastructure. Currently, a lack of point source filtration and complicated physiochemical data acquisition hinder mainstream UAV deployment in the context of hydrogeochemical studies. The aim of this paper is to provide guidance on effective UAV sampling methods and physiochemical data collection for use in surface water hydrogeochemical mineral exploration. To date, case study surveys have utilized sampling systems where sampled waters are filtered after collection or analyzed for ‘total’ (unfiltered) concentrations. This paper details a methodology for point-source filtration of water samples using a UAV system to recover filter sample aliquots for the determination of ‘dissolved’ (<0.45 μm) trace element concentrations and compares UAV methods to conventional sampling strategies. This study systematically compares the quality of analytical data collected from lakes, ponds, and rivers in the Long Lake area of southern Ontario, using conventional manual sampling (from a boat or canoe) and a series of UAV-based sampling methodologies. The waters sampled within the study area are highly meteoric and show evidence of solute input from water-rock interaction with local country rocks. The results of this study show that in general, conventional sampling methodologies are statistically comparable to samples collected using UAVs. However, there is some evidence of element variation related to lake stratification, with dissolved Cu concentrations higher in samples collected at depth compared to those from the surface. Similarly, samples filtered after collection typically have lower concentrations of Fe and Mn, potentially resulting from precipitation before filtration. An enclosed sampling system offered from peristaltic pumping with in-line filtration removes the potential for contamination from the surrounding environment and from the UAV itself.

Multivariate statistical and hydrogeochemical analysis of seasonal groundwater quality variations in coastal villages of Trivandrum district, south India

This study attempts a detailed assessment of the quality of groundwater in the coastal region of Trivandrum District, Kerala where groundwater is the main source of drinking water. Forty groundwater samples were collected during the pre-monsoon and post-monsoon periods. The collected samples were analyzed for physical properties such as electrical conductivity (EC), pH, total dissolved solids (TDS), and total hardness, along with chemical properties, including major cations (Ca2⁺, Mg2⁺, Na⁺, K⁺) and anions (Cl⁻, SO₄2⁻, HCO₃⁻, NO₃⁻). The analysis of groundwater quality reveals significant spatial and seasonal variations caused by both natural and manmade influences. Water Quality Index (WQI), hydrogeochemical plots, and Principal Component Analysis (PCA) were used to analyses the data. The results show that Vakkom, Kazhakottam, Veli-Attipara, and Pozhiyoor show significant deterioration, and areas such as Varkala, Ayroor, and Edava generally maintain good water quality. The Water Quality Index (WQI) assessment indicates that approximately 22.5% of the studied area falls under excellent quality, while 17.5% is classified as poor. The WHO standard and BSI standards were used to derive the WQI. Principal Component Analysis (PCA) identified electrical conductivity, total dissolved solids, and total hardness as the primary factors affecting groundwater quality, explaining 65.17% and 61.03% of the total variance in the pre-monsoon and post-monsoon periods, respectively. Hydrochemical plots collaborate these results, emphasize the influence of rock-water interactions as the main geochemical process, further compounded by pollution from agricultural runoff and urban development. These findings highlight the need for sustainable groundwater management strategies in coastal communities. Effective measures, including pollution mitigation, sustainable agricultural practice, proper waste management, and preservation of freshwater ecosystems, are essential for ensuring the sustainability of groundwater resources.

Magmatic and rock-leaching contributions to the metal load in hydrothermal fluids at þeistareykir, Iceland

Magmatic-hydrothermal systems are key environments to study the transfer of elements from the deep Earth to the surface and the mobilization and re-distribution of elements within the crust. These systems have been recognized as potential active analogue sites for ore deposition. The source of fluids and their metal load is split between the relative contributions from degassing of underlying magma and interactions between the hydrothermal fluid and the host rock. Here, we combine analyses of noble gases and volatile metals in fluids and rocks from the þeistareykir geothermal field (NE Iceland) to provide constraints on the relative contribution of these two sources. Helium isotope data suggest 80–85% originated from magma degassing. The 3He/4He ratio, corrected for atmospheric contamination (Rc/Ra) correlates with volatile metal abundances in surface fluids and indicates that Bi and Hg are predominantly derived from magma degassing. It is also shown that the deep geothermal reservoir fluid is dominated by magmatic input, except for Mn, Fe, Co, Cu, Ti and V, using the elemental signature of magmatic degassing and water-rock interaction. The spatial variations in Rc/Ra and surface fluid volatile metal contents among the wells suggest an impact of the local and regional structures on the fluid's pathway from depth to surface.

Evolution of the Caprock Sealing Capacity Induced by CO2 Intrusion: A Simulation of the Dezhou Dongying Formation

CO2–water–rock interactions have an important impact on the stability and integrity of the caprock in CO2 geological storage projects. The injected CO2 in the reservoir enters the caprock via different mechanisms, leading to either the dissolution or precipitation of minerals. The mineral alterations change the porosity, permeability, and mechanical properties of the caprock, affecting its sealing capability. To evaluate the sealing effectiveness of overlying caprock and identify the influencing factors, numerical simulations and experiments were carried out on the mudstone Dongying Formation in Dezhou, China. Based on high-temperature and high-pressure autoclave experiments, batch reaction simulations were performed to obtain some key kinetic parameters for mineral dissolution/precipitation. Then, they were applied to the following simulation. The simulation results indicate that gaseous CO2 has migrated 7 m in the caprock, while dissolved CO2 migrated to the top of the caprock. Calcite is the dominant mineral within 1 m of the bottom of the caprock. The dissolution of calcite increases the porosity from 0.0625 to 0.4, but the overall porosity of the caprock decreases, with a minimum of 0.054, mainly due to the precipitation of montmorillonite and K-feldspar. A sensitivity analysis of the factors affecting the sealing performance of the caprock considered the changes in sealing performance under different reservoir sealing conditions. Sensitivity analysis of the factors affecting the sealing performance of the caprock indicates that the difference in pressure between reservoir and caprock affects the range of CO2 transport and the degree of mineral reaction, and the sealing of the caprock increases with the difference in pressure. Increasing the initial reservoir gas saturation can weaken the caprock’s self-sealing behavior but shorten the migration distance of CO2 within the caprock. When the content is lower than 2%, the presence of chlorite improves the sealing performance of the caprock and does not increase with further chlorite content. This study elucidates the factors that affect the sealing ability of the caprock, providing a theoretical basis for the selection and safety evaluation of CO2 geological storage sites.

Groundwater Geochemistry in the Karst-Fissure Aquifer System of the Qinglian River Basin, China

The Qinglian River plays a significant role in China’s national water conservation security patterns. To clarify the relationship between hydrogeochemical properties and groundwater quality in this karst-fissure aquifer system, drilling data, hydrochemical parameters, and δ2H and δ18O values of groundwater were analyzed. Multiple indications (Piper diagram, Gibbs diagram, Na+-normalized molar ratio diagram, chloro-alkaline index 1, mineral saturation index, and principal component analysis) were used to identify the primary sources of chemicals in the groundwater. Silicate weathering, oxidation of pyrite and chlorite, cation exchange reactions, and precipitation are the primary sources of dissolved chemicals in the igneous-fissure water. The most relevant parameters in the karst water are possibly from anthropogenic activities, and other chemicals are mostly derived from the dissolution of calcite and dolomite and cation exchange reactions. Notably, the chemical composition of the deep karst water from the karst basin is mainly influenced by the weathering of carbonate and cation exchange reactions and is less affected by human activities. The hydrogeochemical properties of groundwater in the karst hyporheic zone are influenced by the dissolution of carbonates and silicates, evaporation, and the promotion effect of dissolution of anorthite or Ca-containing minerals. Moreover, the smallest slope of the groundwater line from the karst hyporheic zone among all groundwater groups revealed that the mixing effects of evaporation, isotope exchange in water–rock interaction or deep groundwater recharge in the karst hyporheic zone are the strongest. The methods used in this study contribute to an improved understanding of the hydrogeochemical processes that occur in karst-fissure water systems and can be useful in zoning management and decision-making for groundwater resources.

Hydrogeochemical Processes in Basement Areas Using Principal Component in Burkina Faso (West African Sahel)

The basement aquifers in Burkina Faso are increasingly exposed to groundwater pollution, largely due to socio-economic activities and climatic fluctuations, particularly the reduction in rainfall. This pollution makes the management and understanding of these aquifers particularly complex. To elucidate the processes controlling this contamination, a methodological approach combining principal component analysis (PCA) and multivariate statistical techniques was adopted. The study analyzed sixteen physicochemical parameters from 58 water samples. The primary objective of this research is to assess groundwater quality and deepen the understanding of the key factors influencing the spatial variation of their chemical composition. The results obtained will contribute to better planning of preservation and sustainable management measures for water resources in Burkina Faso. The results show that three principal components explain 72% of the variance, identifying anthropogenic inputs, with two components affected by mineralization and one by pollution. The study reveals that the groundwater is aggressive and highly corrosive, with calcite saturation. Water-rock interactions appear to be the main mechanisms controlling the hydrochemistry of groundwater, with increasing concentrations of cations and anions as the water travels through percolation pathways. PCA also revealed that the residence time of the water and leaching due to human activities significantly influence water quality, primarily through mineralization processes. These results suggest that rock weathering, coupled with reduced rainfall, constitutes a major vulnerability for aquifer recharge.

Spatial Variations and Regulating Processes of Groundwater Geochemistry in an Urbanized Valley Basin on Tibetan Plateau

Groundwater resource is crucial for the development of agriculture and urban communities in valley basins of arid and semiarid regions. This research investigated the groundwater chemistry of a typical urbanized valley basin on the Tibetan Plateau to understand the hydrochemical status, quality, and controlling mechanisms of groundwater in arid urbanized valley basins. The results show groundwater is predominantly fresh and slightly alkaline across the basin, with approximately 54.17% of HCO3-Ca type. About 12.5% and 33.33% of sampled groundwaters are with the hydrochemical facies of Cl-Mg·Ca type and Cl-Na type, respectively. Groundwater is found with the maximum TDS, NO3−, NO2−, and F− content of 3066 mg/L, 69.33 mg/L, 0.04 mg/L, and 3.12 mg/L, respectively. Groundwater quality is suitable for domestic usage at all sampling sites based on EWQI assessment but should avoid direct drinking at some sporadic sites in the urban area. The exceeding nitrogen and fluoride contaminants would pose potential health hazards to local residents, but high risks only existed for infants. Both minors and adults are at medium risk of these exceedingly toxic contaminants. Groundwater quality of predominant sites in the basin is suitable for long-term irrigation according to the single indicator of EC, SAR, %Na, RSC, KR, PI, and PS and integrated irrigation quality assessment of USSL, Wilcox, and Doneen diagram assessment. But sodium hazard, alkalinity hazard, and permeability problem should be a concern in the middle-lower stream areas. Groundwater chemistry in the basin is predominantly governed by water-rock interaction (silicate dissolution) across the basin in natural and sporadically by evaporation. Human activities have posed disturbances to groundwater chemistry and inputted nitrogen, fluoride, and salinity into groundwater. The elevated nitrogen contaminants in groundwater are from both agricultural activities and municipal sewage. While the elevated fluoride and salinity in groundwater are only associated with municipal sewage. It is imperative to address the potential anthropogenic contaminants to safeguard groundwater resources from the adverse external impacts of human settlements within these urbanized valley basins.

Hydrogeochemical Insights into the Sustainable Prospects of Groundwater Resources in an Alpine Irrigation Area on Tibetan Plateau

The Tibetan Plateau is the “Asia Water Tower” and is pivotal for Asia and the whole world. Groundwater is essential for sustainable development in its alpine regions, yet its chemical quality increasingly limits its usability. The present research examines the hydrochemical characteristics and origins of phreatic groundwater in alpine irrigation areas. The study probes the chemical signatures, quality, and regulatory mechanisms of phreatic groundwater in a representative alpine irrigation area of the Tibetan Plateau. The findings indicate that the phreatic groundwater maintains a slightly alkaline and fresh status, with pH values ranging from 7.07 to 8.06 and Total Dissolved Solids (TDS) between 300.25 and 638.38 mg/L. The hydrochemical composition of phreatic groundwater is mainly HCO3-Ca type, with a minority of HCO3-Na·Ca types, closely mirroring the profile of river water. Nitrogen contaminants, including NO3−, NO2−, and NH4+, exhibit considerable concentration fluctuations within the phreatic aquifer. Approximately 9.09% of the sampled groundwaters exceed the NO2− threshold of 0.02 mg/L, and 28.57% surpass the NH4+ limit of 0.2 mg/L for potable water standards. All sampled groundwaters are below the permissible limit of NO3− (50 mg/L). Phreatic groundwater exhibits relatively good potability, as assessed by the entropy-weighted water quality index (EWQI), with 95.24% of groundwaters having an EWQI value below 100. However, the potential health risks associated with elevated NO3− levels, rather than NO2− and NH4+, merit attention when such water is consumed by minors at certain sporadic sampling locations. Phreatic groundwater does not present sodium hazards or soil permeability damage, yet salinity hazards require attention. The hydrochemical makeup of phreatic groundwater is primarily dictated by rock–water interactions, such as silicate weathering and cation exchange reactions, with occasional influences from the dissolution of evaporites and carbonates, as well as reverse cation-exchange processes. While agricultural activities have not caused a notable rise in salinity, they are the main contributors to nitrogen pollution in the study area’s phreatic groundwater. Agricultural-derived nitrogen pollutants require vigilant monitoring to avert extensive deterioration of groundwater quality and to ensure the sustainable management of groundwater resources in alpine areas.

Study on Mechanical and Acoustic Emission Characteristics of Coal Gangue during Compression under Water-Rock Interaction

Study on Mechanical and Acoustic Emission Characteristics of Coal Gangue during Compression under Water-Rock Interaction

Geogenic and anthropogenic factors influencing groundwater quality for irrigation purposes from a volcano-sedimentary aquifer in the Puebla State, Mexico.

This study investigates the hydrogeochemical characteristics and water quality of the Puebla Valley aquifer, a volcano-sedimentary system predominantly influenced by water-rock interactions and ion exchange processes. The research assesses the suitability of groundwater for agricultural irrigation by applying various water quality indices, including salinity and sodicity indices and Wilcox diagrams and USSL. Seventy-one water samples were analyzed to determine key physicochemical parameters and dominant ion concentrations, revealing that the primary hydrogeochemical facies are HCO -Mg and HCO -Ca. The results indicate a heightened risk of salinization, particularly in agricultural and urban areas, underscoring the need for ongoing monitoring. Natural processes such as water-rock interaction and ion exchange are the main factors influencing groundwater quality. However, anthropogenic activities, particularly the use of fertilizers and irrigation return flows from the Atoyac River, exacerbate groundwater quality degradation. This study emphasizes the necessity of sustainable water resource management to ensure the long-term viability of the aquifer.

Sulfonated corn stalk enhanced hydrogel adsorption for heavy metal from metal mine gallery effluent

There are various of abandoned metal mines in China, and a considerable amount of heavy metal contaminated water is generated through water–rock interactions and accumulated within metal mine gallery. Therefore, the effective removal of heavy metals from metal mine gallery effluent holds significant importance. In this study, sulfonated corn stalk (SCS) and acrylic acid was used to prepare the double network hydrogel SCS-gel. The maximum allowable compression force for the SCS-gel was about 3 times than that of raw hydrogel. The SCS-gel exhibited a stable adsorption capacity within the pH range from 2.0 to 6.0. The maximal adsorption capacities of Pb2+ and Cu2+ on the SCS-gel were 111.6 and 370.2 mg/g, respectively. The functional groups of –OH, C-O, C = O, COOH, and −SO3- were participated in the adsorption process through coordination and electrostatic interactions. The SCS-gel exhibited promising reusability as the adsorption efficiency for Pb2+ and Cu2+ remained at approximately 100 % within 10 cycles of adsorption–desorption. The SCS-gel had an excellent removal efficiency for Pb2+ (99.8 %), Cu2+ (99.1 %), Mn2+ (97.4 %), Zn2+ (98.8 %), and Al3+ (95.7 %) from actual metal mine gallery effluent by dosage of 5 g/L with the initial concentrations of Pb2+, Cu2+, Mn2+, Zn2+, and Al3+ were 4.352, 29.20, 13.02, 7.016, and 30.47 mg/L, respectively. In the fixed-bed experiments, the Thomas model has a good description for the breakthrough curves of these heavy metals. These results confirmed the possibility of adopting SCS ethers for hydrogel fabrication and verified its great potential for the practical application for the removal of heavy metals from metal mine gallery effluent.