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Groundwater, a vital source of water supply, is currently experiencing a pollution crisis that poses a significant risk to human health. To understand the hydrochemical formation mechanisms, quality and risk to human health of groundwater in the upper reaches of the Wulong River basin, 63 sets of groundwater samples were collected and analyzed. A combination of mathematical statistics, correlation analysis, Gibbs diagram, ion ratio, and cation exchange were comprehensively employed for hydrochemical analysis, and further water quality index (WQI) and human health risk assessment were conducted. The results indicate that groundwater is generally neutral to weakly alkaline. The dominant cations in the groundwater are Ca2+ and Mg2+, while the main anions are HCO3− and SO42−. The hydrochemical types of groundwater mainly include HCO3·SO4-Ca, HCO3-Ca and HCO3-Na. The diverse hydrochemical types are mainly due to the fractured and discontinuous nature of the aquifers. The hydrochemical characteristics are influenced by the dissolution of silicate and carbonate minerals, cation exchange processes, and anthropogenic pollution. The presence of NO3− in groundwater is primarily attributed to agricultural activities. The groundwater is mainly categorized as "Good" (36.6%) and "Poor" (60.8%). "Very poor" and "Excellent" categories are rare, accounting for only 1.2% and 1.4%, respectively, and no samples are classified as "Non-drinkable". The Ewi for NO3− is the highest, indicating severe contamination by anthropogenic NO3− pollution. Human health risk assessment reveals that water samples posing exposure risks account for 82.54% for children and 79.37% for adults. This study highlighted that anthropogenic nitrate pollution has deteriorated groundwater quality, posing risks to human health. It also suggests an urgent need to enhance research and protective measures for groundwater in similar regions, such as the Shandong Peninsula. [ABSTRACT FROM AUTHOR]

The document provides a historical account of the development of artesian wells in Batavia, Dutch East-Indies (now Jakarta, Indonesia) from 1872 to 1878. Due to contaminated water sources causing disease outbreaks, nine artesian wells were drilled to provide clean groundwater. The wells were constructed using advanced drilling techniques and provided good-quality drinking water. The success of these wells led to increased interest in artesian well drilling in the United States. [Extracted from the article]

In a global context, the hydrochemical characteristics of shallow groundwater in coalfields exhibit high degrees of diversity and complexity that are rooted in the intricate interplay of geological variations, diverse climatic conditions, and extensive human activities. The specific types and concentrations of ions, such as Ca2+, Cl−, and NO3−, show stark differences across geographical regions. Given the crucial roles of coalfields as energy suppliers, the potential environmental contamination risks posed by mining activities to groundwater cannot be overlooked as such pollution directly impacts human health and ecological safety. This study focuses on the Huainan coal mining area in northern Anhui Province (China), where shallow groundwater samples were systematically collected and analyzed to determine the hydrochemical characteristics and ascertain the water quality status. By integrating hydrogeochemical analysis techniques with inverse modeling methods, it was revealed that the groundwater in this region is predominantly HCO3-Ca type, exhibiting weak alkaline characteristics. The formation mechanisms are primarily governed by silicate rock weathering and mineral dissolution-precipitation processes, albeit with discernible influences from human activities. PHREEQC simulations were used to further confirm the precipitation tendencies of minerals like calcite, dolomite, and fluorite as well as the significant dissolution characteristics of halite. The inverse modeling pathway analysis reveals specific hydrochemical processes along different paths: paths I and IV are notably dominated by Ca2+ dissolution-precipitation and cation exchange-adsorption processes, whereas paths II and III are closely associated with the precipitation of calcium montmorillonite as well as dissolution of kaolinite, calcite, quartz, and mineral incongruents. Moreover, evaluations based on the entropy-weighted water quality index (EWQI) indicated overall positive trends of the groundwater quality indicators within the Huainan mining area, reflecting the effectiveness of regional water quality management efforts and providing a scientific basis for future water quality protection and improvement strategies. In summary, this study not only deepens our understanding of the groundwater chemistry in the Huainan coal mining area but also underscores the importance of scientifically assessing and managing groundwater resources to address the environmental challenges potentially arising from coal mining activities. [ABSTRACT FROM AUTHOR]

ABSTRACT Groundwater quality assessment is crucial for ensuring safe drinking water, protecting public health, and maintaining sustainable water resources for agricultural and industrial uses. The Awash River basin faces significant groundwater quality challenges due to rapid population growth, high urbanization, large‐scale irrigation, and industrial pollution. The main objective of this study is to evaluate the intrinsic vulnerability of aquifers to pollution in the Awash Basin and identify hotspots requiring urgent intervention using a modified DRASTIC overlay analysis method. In addition to the seven parameters considered in the generic DRASTIC overlay analysis (depth to the water table, recharge, aquifer media, slope, soil media, vadose zone, and hydraulic conductivity), we incorporated land use/land‐cover (LULC) and lineament density (LD) distributions (DRASTIC‐LU‐LD). This modification allowed us to produce more realistic groundwater vulnerability maps for the basin. To identify the most influential parameters in the overlay, sensitivity analysis was conducted using Map Removal Sensitivity Analysis (MRSA) and Single Parameter Sensitivity Analysis (SPSA). Initially, the generic DRASTIC index in the area ranges from 69 to 181, categorizing the area into four vulnerability zones: very low (21%), low (51%), medium (27%), and high (1%). After incorporating LU and LD, the index values ranged from 90 to 240. Based on the percentage of the total area studied, the inclusion of LU decreased the very low and low vulnerability zones from 72% to 44% and the inclusion of LD increased the high‐ and very‐high‐vulnerability zones from 14% to 27%. The areas most vulnerable to groundwater pollution are in the western (upper Awash), middle Awash, and northwestern regions, particularly in city centers where groundwater abstraction is significant. These high‐vulnerability zones coincide with municipal, industrial, and agricultural pollution sources. The vadose zone parameter has the highest impact in both MRSA and SPSA, with a variation index value of 3.08% and a mean effective weight of 27.93%, respectively. By identifying areas vulnerable to groundwater pollution, this study provides a valuable basis for informed decision‐making and the development of effective strategies for protecting groundwater from urban, industrial, and agricultural pollution sources. [ABSTRACT FROM AUTHOR]

Explicit identification of hydrochemical processes and their controlling factors within groundwater systems is critical for the sustainable utilization of water resources in coastal urban areas. This study was undertaken in the North Coastal Region of Jiaozhou Bay (NCRJB), located in the eastern part of Shandong Province, China, an area grappling with significant issues of groundwater quality degradation and water scarcity. A total of 105 groundwater samples and 34 surface water samples, collected from 2020 to 2024, were analyzed and studied using various hydrogeological tools, multivariate statistical analyses, and water quality assessment methods. These include the Piper diagram, hydrochemical facies evolution diagram (HFE-D), Principal Components Analysis (PCA), correlation analysis, stable isotope analysis, Water Quality Index (WQI), and USSL diagrams. The results indicated that all surface water and pore groundwater samples were categorized as Na-Cl type, exhibiting high Total Dissolved Solids (TDS) and Electrical Conductivity (EC) values, characteristics that render them poor to unsuitable for drinking and irrigation purposes. The fracture groundwater is predominantly of the Ca-Na-Cl mixed type, with average suitability for irrigation and a limited proportion (22.5%) deemed suitable for drinking. Seawater intrusion, primarily through the surface water system, and the impact of human activities were identified as the predominant controlling factors con-tributing to the degradation of the local groundwater environment. Field empirical investigations further validated the results derived from hydrogeological assessments, multivariate statistical analyses, and isotopic approaches. The long-term shifts in hydrochemical properties, along with the latent threat of seawater intrusion, exhibit an upward trend during the dry season and show a certain degree of mitigation during the wet season. This study highlights that field investigations, in conjunction with hydrochemical tools, multivariate statistical analyses, and stable isotope analysis, can successfully furnish reliable insights into the predominant mechanisms governing regional groundwater evolution within the context of long-term and intricate envi-ronmental settings. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to the spatiotemporal design of groundwater quality monitoring networks for coastal aquifers. A fusion model combines the outputs of several developed simulation models to make estimates more accurate. A modified GALDIT method is used to incorporate the aquifer vulnerability to saltwater intrusion. The value of information (VOI) theory is applied to determine sufficient monitoring wells. The groundwater quality monitoring network is designed by employing a robust decision-making (RDM) approach under different management strategies and economic considerations. This approach incorporates the deep uncertainties of some critical variables, including water level and total dissolved solids (TDS) concentration at the coastline and pumping flow rates of agricultural wells. The new methodology is implemented in the coastal Qom-Kahak aquifer, Iran. The results illustrate that the combination model has significantly improved evaluation criteria compared to individual prediction models. The fusion model results indicate that thirty monitoring wells would be ideal. The RDM-based analyses in the Qom-Kahak aquifer showed that an optimal network with 30 monitoring wells outperforms the current network regarding various criteria, such as VOI and variance of estimation error. The new well configuration also demonstrates a suitable spatial distribution. Given that the current sampling frequencies are unsuitable for areas with varying vulnerabilities, we recommend sampling every 3 months in areas with moderate vulnerabilities and once every three seasons in areas with low vulnerabilities, based on the information transfer index. Finally, a management strategy in which the pumping rate should be less than 60% of the current rate is suggested to prevent saltwater intrusion into the aquifer. [ABSTRACT FROM AUTHOR]

Population growth and expanding urbanization have caused persistent shortages and contamination of groundwater resources in Mali, Africa. The increase in groundwater salinity makes it more difficult for residents to obtain drinking water, it is necessary to clarify the causes and control factors of groundwater mineralization in Gao region, northern Mali. Based on the analysis of the hydrochemical composition of groundwater in 24 boreholes, Piper and Schöeller diagrams, principal component analysis (PCA) and hierarchical cluster analysis (HCA) are used to carry out multivariate statistical analysis on the main ions. The results show that the groundwater samples are weakly alkaline, with pH values ranging from 5.83 to 8.40, and the average values of boreholes are 7.50, respectively. The average electrical conductivity (EC) value is 354.4 (µS/cm), and the extreme value is between 124.0 and 1 247 (µS/cm). Water is usually mineralized and presents nine types of water phase. The three principal components explain 84.42% of the total variance for 13 parameters. The factor F1 (58.85%), the factor F2 (16.88%) and the factor F3 (8.69%) present for the majority of the total data set. In addition, multivariate statistical analysis confirmed the genetic relationship among aquifers and identified three main clusters. Clustering related to groundwater mineralization (F1), clustering related to oxide reduction and iron enrichment (F2), and clustering of groundwater pollution caused by nitrate and magnesium (F3). We found that agriculture, weathering activities and dissolution of geological materials promote the mineralization of groundwater. Groundwater quality in the Gao region is becoming less and less potable because of increasing salinity. [ABSTRACT FROM AUTHOR]

Greensand filtration is a common treatment option for manganese, sulfide, and iron removal; poor maintenance, however, can compromise effectiveness and even lead to increased post-treatment Mn concentrations. A private drinking-water well in exceedance of Health Canada's maximum allowable concentration for Mn was sampled over a 1-year period to assess Mn removal via greensand filtration. Mn concentrations post-treatment were on average twofold higher than raw well water prior to media change. Reducing conditions, evidenced by negative oxidation–reduction potential (ORP) of the effluent, were central to generating soluble Mn(II). Monitoring revealed that water usage patterns caused variability in post-treatment Mn, with peak concentrations (>3.5× higher than influent water) observed after a 7-day idle period. As inadequate oxidant addition can lead to reducing conditions, monitoring ORP may facilitate proxy surveillance for Mn release. Findings underscore the importance of human factors (e.g., aesthetic concerns, barriers to maintenance, perceived risk) when evaluating overall benefits and drawbacks of treatment systems. [ABSTRACT FROM AUTHOR]

Mining overburden bed separation grouting is an effective method for controlling coal mining subsidence. However, the slurry that is injected into the overburden bed separation space may impact the groundwater environment during the precipitation and consolidation process. To evaluate the impact of overburden bed separation grouting on the groundwater environment, coupled numerical simulations of groundwater flow and solute transport were carried out with the background of a grouting project in Northern China. In addition, the shallow groundwater quality at the site is monitored and evaluated. The results show that the groundwater level rises as a result of grouting and that the direction of groundwater flow changes in the vicinity of the grouting boreholes. After the end of the grouting project, the groundwater flow field gradually returned to its natural state. The characteristic solute aluminium in the slurry precipitation water slightly contaminates the aquifer above the grouted bed separation space, but the contamination remains within the working face. The contamination gradually disappears after the end of the grouting project. The evaluation results of the shallow groundwater samples collected before and after grouting showed little difference, suggesting that grouting did not significantly affect the quality of the shallow groundwater. The research results provide theoretical support for the protection of groundwater in mining overburden bed separation grouting areas. [ABSTRACT FROM AUTHOR]

Water resources in arid and semi-arid regions are constrained by several critical problems, including scarcity of water resources and extensive use of groundwater. Climate change and population growth will certainly result in a decline in water tables and degradation of groundwater quality. The purpose of this study is to create rainwater retention ponds in the Najran Valley located at the southern border of Saudi Arabia. Over the past decade, various researchers have reported a sharp decrease in the availability of water in the area. In addition to urban sprawl, excessive groundwater extraction is the primary cause of the decrease. Even though the valley receives a sufficient amount of rainfall throughout the year, there is no adequate rainwater management system in place. As a result of this combined water management issue, the authorities are seeking additional water storage options in addition to the Najran dam reservoir. To evaluate the flood characteristics of the region, an extensive GIS-based hydrological study is conducted. To estimate flood volumes, the critical flood-prone areas are identified and their catchments are calculated. To store rainwater generated by these catchments during rainfall events, a variety of suitable locations have been proposed for retention ponds. The construction of retention ponds would have numerous environmental benefits in addition to solving the problem of water scarcity. As a result of the study, the authorities will be able to implement a management strategy that maximizes the use of the region's water resources. [ABSTRACT FROM AUTHOR]

Coal occupies a dominant position in China’s energy structure. However, overburden failure is the root cause of several safety and environmental issues. With the successive proposals of green mining and the dual-carbon strategy, the green development of coal-based energy has become the priority development direction. Overburden grout injection has become the preferred choice in the green mining technology system. The potential ecological health risk of heavy metal contamination in fly ash matrix soil was analyzed and evaluated in Xinyi coalmine. It is pointed out that only using fly ash as grouting material may cause irreversible harm to groundwater system. Based on the solid waste utilization and sustainable development, the close packing theory was adopted to determine that poorly graded gangue can be used as filling aggregate. Meanwhile, the passivation characteristics of loess to reduce the heavy metal in fly ash by increasing the water-stable aggregate content were elucidated. The properties and parameters of grouting materials composed of gangue, loess, and fly ash were analyzed, and a reasonable upper limit of slurry concentration was determined to be 72%. The field application indicates that the maximum surface subsidence is 473 mm, and the damage degree of buildings is within grade I, liberating 163 Mt of coal resources under the buildings. The harmless treatment of solid waste has been achieved, effectively reducing the negative external impact of coal mining. It is equivalent to saving 95.95 million yuan while promoting the green, safe, and sustainable development of coal enterprises. [ABSTRACT FROM AUTHOR]

In Southwestern Ghana, groundwater is highly needed for several uses, including drinking, domestic, agricultural, and socioeconomic activities. Groundwater mineralization is usually controlled by natural processes and anthropogenic activities. The mineralization processes and other latent processes can render groundwater unsuitable for human usage. Thus, there is a need for continuous assessment of groundwater. This study aimed to assess the controls of groundwater mineralization in 105 sample stations within the Southwest of Ghana using pollution indexing, hydrochemical, multivariate statistical, and multiple linear regression (MLR) modeling. The tests for physicochemical characteristics followed standard methods. The ionic concentrations of the samples were within acceptable limits, except for nitrate in some locations. The hydrochemical analyses revealed that the water types predominated in the order of Ca–HCO3 > Mg–HCO3 > Ca–Cl > Mg–Cl > Na–HCO3 > Na–Cl. It was also indicated from selected proxies, discriminant diagrams, and multivariate statistical analyses that silicate mineral dissolution and evaporation–crystallization processes are the main controls of the mineralization in the research area. Also, the mineralization processes were noted to be facilitated by the deep and long residence time of groundwater within aquifers. The extent of contamination and suitability of the groundwater for human consumption were evaluated using percentage of pollution index (PPI) and groundwater pollution index (GPI). Their results suggest that 75% of the samples were highly–very highly polluted. The MLR models excellently predicted the relationships between the groundwater quality parameters. They also indicated that the PPI and GPI were mostly influenced by Ca2+, Cl−, HCO3−, F−, and HCO3− concentrations. [ABSTRACT FROM AUTHOR]

Assessing the groundwater quality is important for the efficient exploitation of water resources in semi-arid areas. The study area in northeast Algeria mostly depends on groundwater as its main source of water, and the quality of groundwater is becoming important due to the increasing need for freshwater. The hydrochemical characteristics and water quality of groundwater in the Tebessa-Ain Chabro were assessed using water quality indices, geochemical modeling, and multivariate statistical approaches. The study discovered that the groundwater samples could be classified into four distinct water groups using hierarchical cluster analysis in Q mode (HCA) based on their electrical conductivity. We identified three forms of water: mixed (Ca2+–Mg2+–Cl−), Na+–K+–HCO3−, and Ca2+–Cl−. According to the water quality assessment, only 38% of the samples were deemed suitable for human consumption, while 34% were categorized as poor water, 10% as extremely poor, and 17% as unsafe for drinking. The irrigation water quality index identified four classifications: low, moderate, high, and severe restriction, with corresponding percentages of 31%, 31%, 7%, and 31%. The nitrate pollution index (NPI) showed that 48% of samples fell into the moderate pollution class. Human activity, such as sewage infiltration and waste disposal in open areas, was the cause of this nitrate contamination. The saturation index values showed that groundwater was less saturated in halite and sylvite and more saturated in aragonite, calcite, dolomite, anhydrite, gypsum, and hydroxyapatite. The Tebessa region's groundwater's hydrochemical properties and water quality have been assessed using multivariate statistical techniques, geochemical modeling, and water quality indexes. The study's conclusions can provide a foundation for upcoming research evaluating the region's groundwater quality. [ABSTRACT FROM AUTHOR]

A modified DRASTIC model, named DRASTLZ, has been proposed to better assess the sensitivity of groundwater systems to pollution by replacing the vadose zone media type (I) and hydraulic conductivity of the aquifer (C) with land use type (L) and groundwater quality (Z) indicators. First, a scoring system for the DRASTLZ model was established, assigning different weights to seven influencing factors. Using the ArcGIS platform, collected data were processed and statistically analyzed. Evaluation score maps were constructed for seven assessment indicators: groundwater depth (D), net recharge of groundwater (R), aquifer media (A), soil media (S), surface slope (T), land use type (L), and groundwater quality (Z). These maps were then overlaid, and the composite vulnerability index of Juxian County was calculated according to the assigned weights. The natural breaks classification method was employed to divide the area into five vulnerability zones: low vulnerability, relatively low vulnerability, moderate vulnerability, relatively high vulnerability, and high vulnerability. The groundwater vulnerability assessment for Juxian County was thereby completed. The calculated results indicate that the overall vulnerability of groundwater in Juxian County is relatively high, with the highest proportion (approximately 38%) falling in the high vulnerability zone, followed by moderate vulnerability (36%) and high vulnerability (15%) zones. The proportions of relatively low and low vulnerability zones are smaller, accounting for 10% and 1%, respectively. There is a positive correlation between groundwater vulnerability assessment results and the exceedance of water quality sampling points, suggesting the applicability of the developed DRASTLZ model in Juxian County closely reflects actual conditions. The successful application of the DRASTLZ model provides valuable experience and guidance for future groundwater vulnerability assessment studies in similar regions. [ABSTRACT FROM AUTHOR]

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca2+ > Mg2+ > Na+ > K+ and HCO3− > SO42− > Cl− > NO3− > F− during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO3–Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water–rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO3− and SO42− were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection. [ABSTRACT FROM AUTHOR]

Chemical and isotopic indicators were used to recognize the origin of hydrothermal groundwater, to assess the mineralization processes and groundwater quality, to identify the source of solutes and the likely mixing with cold, and elucidate the fluid geothermometry in the Jérid field of Southern Tunisia. The results show that the geothermal groundwater is neutral to slightly alkaline. They are characterized by SO4-Cl-Na-Ca water type. The dissolution of evaporates and pyrite-bearing rocks is the dominant mineralization process. The groundwater quality index indicates that the majority of samples are very hard and belong to poor to unsuitable for drinking classes. Applications and calculations of hydrogeochemical parameters, including SAR, %Na, PI, Kr, and MAR, showed that the majority of samples are unsuitable for agricultural practices. The human health risk was assessed based on hazard quotient and total hazard index through ingestion and dermal contact with iron-rich groundwater. The consumption of CI groundwaters does not present non-carcinogenic risk to adults and children. The δ18 O and δ2H signatures indicate that the geothermal groundwater was recharged by ocean precipitation during cold and wet paleoclimatic periods. The slight enrichment of oxygen-18 and deuterium contents suggests a limited mixing effect between geothermal water and cold groundwater within the same aquifer. This mixing effect is confirmed by the Na–K-Mg and the chloride-enthalpy diagrams. The K-Mg and SiO2 geothermometers provided fairly reliable reservoir temperature values, ranging between 69.6 and 99 °C. Calculated geothermal potential values, varying between 469 and 16987 kWth, which allow several applications such as domestic and agricultural heating. [ABSTRACT FROM AUTHOR]

Groundwater serves a range of essential functions such as supplying drinking water, facilitating agricultural practices, and supporting industrial processes. This study examines with multiple methods the quality of groundwater in the agricultural region of Dzira, Algeria. By collecting 38 groundwater samples of different wells and boreholes, valuable awareness of the aptness of groundwater for irrigation in this arid landscape was gained. Most wells met Food and Agriculture Organization (FAO) criteria for the total dissolved solids (TDS) and the potential of hydrogen pH, but some areas had higher mineral content and electrical conductivity. Results show significant TDS variations, with 10.81% of wells exceeding limits and acceptable pH levels. Elevated EC values in 67.57% of wells show high salinity, affecting soil and plant growth. Major ions such as Mg2+ and SO4− exceeded FAO standards in 43.24% and 64.86% of wells, respectively, highlighting substantial mineral content in the groundwater. Suitability indices reveal that most wells pose low sodium hazards and are generally suitable for irrigation, though some areas face moderate to high restrictions. The irrigation water quality index (IWQI) ranged from 45.36 to 96.30, averaging 80.77, with 54.04% classified as "low restriction," suitable for sandy soils with good permeability but requiring caution on salt-sensitive soils. Hydrogeochemical analysis using principal component analysis (PCA) and hierarchical cluster analysis (HCA) identifies rapid evaporite dissolution from Triassic saline formations, with a correlation matrix showing associations between TDS and Ca2⁺, Mg2⁺, Na⁺, Cl⁻, and SO₄2⁻. This mineralization is likely from gypsum and halite. Zoning maps based on IWQI and other parameters depicted spatial variations in groundwater quality, guiding effective irrigation management strategies. Overall, the study underscores the importance of comprehensive water quality assessment for sustainable agriculture and emphasizes the need for targeted interventions to mitigate potential challenges associated with soil salinity and sodicity. Therefore, these findings can be useful to decision-makers and stakeholders in order to optimize water use and protect this vital resource. [ABSTRACT FROM AUTHOR]

Groundwater is one of the chief water sources for agricultural activities in an aggregation of coal mines surrounded by agricultural areas in the Huaibei Plain. However, there have been few reports on whether mining-affected groundwater can be adopted for agricultural irrigation. We attempted to address this question through collecting 71 shallow groundwater samples from 12 coal mining locations. The Piper trilinear chart, the Gibbs diagram, the proportional coefficient of major ions, and principal component analysis were examined to characterize the source, origin, and formation process of groundwater chemical composition. The suitability for agricultural irrigation was evaluated by a final zonation map that establishes a comprehensive weighting model based on analytic hierarchy process and criteria importance though the intercriteria correlation (AHP-CRITIC). The results revealed that the groundwater was classified as marginally alkaline water with a predominant cation of HCO3- and anion of Na+. Total hardness, total dissolved solids, sulfate (SO42-), sodium (Na+), and fluoride (F−) were the primary ions that exceeded the standard. The results also indicated that the dominant hydrochemical facies were Ca-HCO3 and Na-Cl. The dissolution of carbonate, silicate, sulfate minerals, along with cation exchange, were the main natural drivers controlling the hydrogeochemical process of groundwater. The zonation map suggested that 43.17%, 18.85%, and 37.98% of the study area were high, mediate, and low suitability zones, respectively. These results from this study can support policymakers for better managing groundwater associated with a concentration of underground coal mines. [ABSTRACT FROM AUTHOR]

The scarcity of groundwater monitoring in Kosovo, particularly in Lipjan, underscores the urgency to assess and safeguard this vital resource amidst escalating water demands and mounting pollution. This study addresses the critical gap in groundwater data by proposing the establishment of a comprehensive monitoring system. The primary goal was to develop a system capable of providing real-time data on groundwater quality and quantity within the capture area. Specific research objectives include the daily real-time monitoring of groundwater quality, identification, and quantification of contaminants in the aquifer, as a basis for further work on delineation of contaminant sources impacting the capture area, and monitoring and quantifying water extraction rates from individual wells, therefore establishing the necessary protection zones. Seven divers have been installed in 7 monitoring wells in Lipjan to measure the water level and pressure, as well as a multiparameter sensor for water quality monitoring for pH, temperature, specific conductivity, total dissolved solids, and dissolved oxygen. The digital monitoring system has been set up to input and log the incoming data. The aim was to gather this data, analyze it and use it to create a model and calibrate it to match the observed data. Concurrently, a sensitivity analysis was performed to prioritize data collection and establish which parameters have the most significant impact on the model outcomes. This ensures the establishment of a model which will, in the future, be used to predict and forecast groundwater levels and quality and determine protection zones. [ABSTRACT FROM AUTHOR]

The evaluation, visualization of environmental data from long-term monitoring, and making them accessible in a processed form in user-friendly interfaces on the Internet are important tasks of our time. The pollution of groundwater resources in settlements is a global phenomenon, the mitigation of which requires a number of environmental measures. In this study, water quality changes following the construction of a sewerage network were examined in the course of long-term monitoring between 2013 and 2022, during which 40 municipal groundwater wells were regularly sampled. Classifying the monitoring data into pollution categories based on water quality index (WQI) and degree of contamination index (Cd), a high degree of contamination was found in the period before the installation of the sewerage network (2014), as the majority of the wells were classified as contaminated and heavily contaminated. In the monitoring period following the installation of the sewerage network, a significant positive change was found in the case of most of the water chemical parameters tested (EC, NH4+, NO2−, NO3−, PO43−). Based on interpolated maps, it was found that an increasing part of the area shows satisfactory or good water quality. This was confirmed by the discriminant analysis as well, as it is possible to determine with an accuracy of 80.4% whether the given sample originates from the period before or after the installation of the sewerage network based on the given water chemical parameters. However, 8 years after setting up the sewerage network, the concentration of inorganic nitrogen forms and organic matter remains high, indicating that the accumulated pollutants in the area are still present. To understand the dynamics of purification processes, additional, long-term monitoring is necessary. Making these data available to members of the society can contribute to appropriate environmental measures and strategies. [ABSTRACT FROM AUTHOR]

In Mexico, aquifers face significant challenges because of contamination and groundwater deficits caused by intensive agriculture. Continuous monitoring of groundwater quality is crucial to ensure sustainable agricultural practices and food production. This study aimed to characterize the hydrogeochemistry and water quality of the Culiacan River Aquifer influenced by intensive agriculture. Groundwater quality data were collected from six sampling sites from 2012 to 2020. The hydrogeochemical facies revealed high concentrations of bicarbonate ions. The results show a mixture of calcium/magnesium and bicarbonate/chloride, indicating an intrusion of saline water in sampling sites close to the coastal zone. Statistical analysis revealed significant differences between the sampling points. Anthropogenic contamination affected SP1 since this site is within the urban area and is the shallowest sampling well. Based on the results of SAR, CSR, SSP, KR, % Na, MH, PI indices, groundwater of SP1 was not suitable for irrigation or drinking use. The water quality indices classified the groundwater of the Culiacan River Aquifer as good in five sampling sites and excellent in one sampling site. The ion content was Na2+ > > Ca2+ > Mg2+ > Cl– > > K+ and did not show any ecological or public health risk. [ABSTRACT FROM AUTHOR]

Prediction of groundwater quality index (GWQI) and quantification of the influence of each key water quality variable is vital for water resource management. This paper shows the potential of the automatic relevance determination-based Bayesian neural network(ARD-BNN) technique for GWQI prediction and compares the predictive performance of ARD-BNN with artificial neural network (ANN), long short-term memory network (LSTM), convolutional neural network (CNN) and hybrid CNN-LSTM. What discriminates the present approach from the previous approach is that GWQI is simulated from the global criteria of WHO and the artificial intelligence (AI) models are trained and cross-validated in a synthetically simulated data set of 1470 examples and applied to predict GWQI using newly collected groundwater samples from an area surrounding Amarpur dolerite dyke, Dhanbad, Jharkhand (INDIA). The present analysis suggests that ARD-BNN is relatively skilful (MSEARD-BNN = 0.01) relative to other AI models investigated (MSEANN = 0.06;MSECNN = 1.60; MSELSTM = 3.85;MSECNN-LSTM = 8.21). The efficacy of the method and stability of results is also tested in the presence of different levels of correlated noise which suggests that the ARD-BNN model is considerably unwavering for up to 20% correlated noise; however, adding more noise (∼50% or more) degrades the results. Sensitivity analysis via ARD-BNN-based soft-pruning strategy identifies that [NO3−], [SO42−],[pH],[F−]and [EC], are key water quality variables for predicting GWQI in the study area. [ABSTRACT FROM AUTHOR]

An effort has been made to develop statistical and ANN models for estimation of sodium concentration in pre-monsoon and post-monsoon seasons using routinely monitored water quality parameters of ground water wells in Jaipur district, Rajasthan (India). The Best Subset procedure based on R2 (coefficient of determination) and F (Fishers test) values was used in model dissemination. It was found that electrical conductivity, hardness, chloride, and sulphate could be used as surrogate parameters for the prediction of sodium. The model values of Na when compared with actual values (validation) showed a reasonably good matching. Further it was noticed that there was not a single model which could be used to predict the Na levels. It is primarily attributed to the fact that sodium concentration not only varies from site to site but also varies from season to season. Secondly, Principal component analysis was used to predict the dominating water quality constituents and it was revealed that four principal components are accounted for the total chemical variability in the ground water quality for pre-monsoon season and three principal components for post-monsoon season, respectively. The common factors conductivity, fluoride, nitrate, alkalinity, and phosphate have perceptible influence on the quality of groundwater of Jaipur district, Rajasthan. Finally, Back Propagation, three layered ANN models for both pre-monsoon and post-monsoon season was developed for estimation of sodium using the steepest descent optimization technique. ANN models were developed considering a fixed number of iterations as 1000 and the developed models were verified on the data not considered in calibration. The input variables considered for different model structures were identified through correlation analysis. Based on the statistical performance evaluation criteria such as root mean square error (RMSE), correlation coefficient (CC), and coefficient of efficiency (CE), the results indicated satisfactory performance of ANN based model. [ABSTRACT FROM AUTHOR]

Groundwater is gradually becoming the primary water source for humans and other living organisms to sustain life on Earth. The groundwater quality in the industrial regions has been significantly contaminated in recent years due to anthropogenic activities, leading to various human health issues. In this study, the groundwater quality and hydrogeochemical characteristics of the Ranipet Industrial Corridor (RIC) were assessed by employing multivariate statistics, standard scatter plots, and the water quality index (WQI). Forty groundwater samples (12 bore wells and 28 open wells) were collected during the post-monsoon (January 2022) season, and the estimation of physicochemical parameters was carried out based on American Public Health Association (APHA) guidelines. The evaporation and rock-water interaction are controlling groundwater hydrochemistry in the study area, as illustrated by Gibbs's diagram. In contrast, 82% of groundwater samples are severely affected by human activity, and 12% are impacted by silicate weathering, illustrated by scatter plots. According to the Chadha diagram, gypsum dissolution is the primary reason for the chemical composition of groundwater in the RIC (87.5%). The primary hydrochemical processes in the study area include silicate weathering, evaporation, ion exchange, and rock-water interaction. The Mukundarayapuram, Navlock, and Melvisharam region's groundwater quality is unsuitable (92.5%) for irrigation due to the high concentration of sodium, based on Sodium Adsorption Ratio (SAR) results. Anthropogenic activities are the primary cause of groundwater degradation and hydrogeochemical changes, with the groundwater quality of RIC being over 60% very poor. A comprehensive treatment procedure before effluent discharge and stringent water regulating policies governed by environmental monitoring organizations are the pressing priorities to build a sustainable environment and reduce the health risks of groundwater. [ABSTRACT FROM AUTHOR]

The study was carried out to evaluate hydro geochemistry and the risk of groundwater and surface water pollution in the Kombolcha area. To achieve this, hydrogeochemical analysis, water heavy metal, geospatial data analysis, correlation matrix, principal component analysis, Heavy metal Pollution Index (HPI), and Water Quality Index (WQI) methodologies were employed. A total of 36 samples (both water and effluent samples) had been collected and assessed for major physicochemical variables and heavy metals. Hydrogeochemical methods showed groundwater mineralization due to (1) silicate weathering, (2) cation exchange processes, and (3) anthropogenic sources (i.e., contaminated discharge of sulphate, carbonate, and trace metal effluents). The study result revealed that major ions dominating the area are Ca2+ > Na+ > Mg2+ > K+, HCO3− > SO 2− > Cl− > NO3−, and Fe > Mn > Pb > Cr > Cd for cations, anions and trace metals respectively with all heavy netals had mean concentrations above the WHO recommended limits. Calculated Pollution indices revealed 50.7% of the sample belongs to a low level of pollution, while 35% and 14.3% belong to a medium and high level of pollution respectively which consequently translating the area into high groundwater pollution zones. The correlation matrix revealed that no significant correlation exists between the water quality variables (Cl and NO3− with Fe, Pb, Cr, Mn, and Cd). PCA was applied on the data set to identify the spatial sources of pollution in groundwater and in the first principal component analysis, Mn, Fe, Cr, Pb, and Cd (in descending order) were found in amounts greater than 0.5, confirming that these metals were from anthropogenic sources. The combined assessments based on WQI and HPI, the study showed that water samples in the proximity of industrial sites are polluted by factories effluent and uncontrolled waste disposal due to urbanization. [ABSTRACT FROM AUTHOR]

Groundwater quality is a serious concern in alluvial aquifers undergoing vast agricultural transformation around the globe. Mehsana district of Gujarat is an example of agricultural landscape having most of the seasonal crops and vegetables. Groundwater samples were collected in monsoon 2017 and pre-monsoon 2018 to analyze major ions and isotopes to derive the hydrochemistry. The hydrochemical facies reveal Na+–Cl−, Na+–HCO3− and Ca2+–HCO3− type water suggesting complex hydrochemical reaction taking place in the region. The scatter plot of Ca2+ + Mg2+ versus HCO3− + SO42− and Na+ versus Cl− shows the ion exchange and silicate weathering along with intermixing of saline water. The presence of high sodium, alkaline pH and bicarbonate promotes the release of fluoride from minerals in groundwater which is high during monsoon. The fluoride concentration increases progressively along the Sabarmati River. The spatial variation map of nitrate in the district shows both point and non-point sources of NO3− contamination. This evidence will support the strong contribution of agricultural activities, as shown by land use that long-term flood irrigation practices have enhanced this impact. The deep aquifers are suitable for drinking purposes as compared to shallow aquifers which are affected with NO3− pollution due to the leaching process during the pre-monsoon season. The agriculture indices show contaminated groundwater for irrigation in more than 50% of wells. The composition of isotopes varied between (δ18O − 2.08 to − 4.41‰ and δD − 19.19 to − 32.28‰). The groundwater trendline was found below the local meteoric water line which indicates evaporation due to semiarid climate before infiltration. [ABSTRACT FROM AUTHOR]

Due to over exploitation of groundwater, there is a drastic decrease in groundwater level and its quality. The groundwater samples have been analysed to estimate its aptness for domestic and agricultural in Sivakasi Taluk industrial areas. In the course of post monsoon and summer of 2020, twenty two samples have been collected from the research area. The groundwater samples were examined for various parameters like pH, EC, TDS, TA, TH, Ca2+, Mg2+, K+, Na+, Cl−, SO4−, HCO3−, F−, DO and samples were compared with BIS, WHO and ICMR standards. It is inferred through results that EC and TDS values were spiked up due to excess presence of Cl−, Na+, Ca2+, Mg2+, F− and NO3− present in water samples near the industrial areas and natural rock formation. The water samples were evaluated for their suitability for irrigation and were assessed by SAR, % Na, Kelly's ratio and MH, USSL diagram shows majority of the samples are apt for agricultural. Piper plot indicates that majority of the collected samples fall under the Na–Cl category thereafter by Mg- HCO3- Cl, Ca–Mg–Cl and Na + K –Cl types and this infers anthropogenic influences. Gibb's plot shows that the collected samples fall under evaporation dominion field followed by rock-water dominion field of the two seasons. It is recommended to provide Artificial Recharge structures, recharge ponds in the area of research to increase the under-groundwater level and its standard. [ABSTRACT FROM AUTHOR]

Determining groundwater quality status and hydro-geochemistry of an aquifer is crucial to ensure cleaner and safer water for human consumption. Groundwater sustainability issues are getting attraction due to global warming and complexities in land utilization. These concerns increased the challenge of gaining an appropriate comprehension of anthropogenic activities and natural processes, as well as how they influence the quality of surface water and groundwater systems. In the present investigation, 48 groundwater samples were collected and analyzed from the Panchkula district of Haryana, located in the Upper Ghaggar River Basin, to explore the sources and driving factors responsible for hydro-geochemistry of the aquifers falling under the natural and anthropogenically intervened areas. Groundwater sampling was carried out in the premonsoon (PRM) as well as postmonsoon (POM) seasons to examine the spatio-seasonal variations in its quality. The results of the study revealed that reverse ion exchange processes are mainly controlling the aquifer geochemistry in areas occupied by natural vegetation, while the nitrate and chloride content of groundwater was the result of anthropogenic activities. The mechanisms governing groundwater quality and the related hydro-geochemical processes were assessed using binary plots of different cations and anions, along with the Gibbs plot and chloro-alkaline indices (CAI). Saturation indices (SI) indicated that groundwater was over-saturated with respect to dolomite, calcite, and aragonite, while 68.75% and 50% of samples indicated under-saturation with respect to anhydride and gypsum, respectively. Principal component analysis (PCA) and Pearson's correlation coefficients were also considered to affirm the processes taking place to control the aquifer chemistry. Groundwater in the majority of the area was found suitable for drinking purposes except in the locations where high nitrate concentrations were recorded, thus suggesting the use of water treatment facilities for such areas. [ABSTRACT FROM AUTHOR]

An investigation of the distribution and control factors of groundwater is significant for the rational exploitation and utilization of groundwater resources. This study analyzes the hydrogeochemical processes and control factors of shallow groundwater in the Guohe River Basin. A hydrogeological survey was conducted, and hydrochemical and hydrogen–oxygen isotopic data of 125 samples of surface water and groundwater were analyzed. The results showed that the total dissolved solid (TDS) content in shallow groundwater was 138–2967 mg/L, with an average of 831 mg/L. A decline in the TDS was observed from the upper to the lower reaches. The contents of the anions and cations in the shallow groundwater were in the order HCO3− > Cl− > SO42− and Na+ and K+ > Mg2+ > Ca2+, respectively. The cation exchange increased the aqueous concentrations of Na+ and K+, and the TDS content was highly correlated with the contents of Na+, Cl−, and SO42− ions. The δD and δ18O values in shallow groundwater increased from the upper to the lower reaches, with the mean δD values being −59.72‰, −53.58‰, and −47.17‰ and the mean δ18O values being −8.33‰, −7.37‰, and −6.43‰. The contribution rates of the recharge source, evaporation, and water–rock interaction to the groundwater TDS concentration were 20.4%, 29.5%, and 50.1%, respectively. The water–rock interaction dominated the formation of shallow groundwater in the Guohe River Basin. The dissolution of salt rock and gypsum contributed to ion formation in shallow groundwater. The research findings can be used to improve the groundwater quality in the Guohe River Basin. [ABSTRACT FROM AUTHOR]

Alluvial fans and deltas are two environments with different hydrochemical conditions. Their junction zones, as mixing environments, are variably influenced by different processes, leading to variable environmental conditions. The purpose of this study is to investigate groundwater quality in the junction zone of these environments in the northern part of the Jazmourian depression (known as the Rudbar plain) in southeastern Iran to determine the dominant processes, assess arsenic and fluoride health risks, and evaluate irrigation water quality. A total of 33 samples from deep drilled wells were taken, and the concentrations of major ions and elements were determined. Additionally, statistical and hydrochemical analyses were undertaken. The dominant processes in the delta are evaporation and ion exchange, while the dominant process in the fan environment is silicate hydrolysis. Among the samples, 26.7% were mainly affected by the delta, and 73.3% were mainly affected by fan conditions. Although the majority of groundwater samples were suitable for irrigation based on quality standards, a significant portion exceeded the acceptable level for Na%. Non-carcinogenic health risk assessments indicated that arsenic hazard risks exceeded thresholds in 63.3% of cases for children and 36% for adults. Carcinogenic health risks associated with arsenic and fluoride exceeded acceptable levels in 4 and 2 stations, respectively. Elevated As concentrations contribute to a greater average health risk in parts of fans environment. [ABSTRACT FROM AUTHOR]

In the Reggane arid region, the Continental Intercalaire (CI) aquifer plays a critical role as a water source, meeting daily water needs such as drinking, domestic use, and agricultural usage. This study assessed the hydrogeochemical characteristics influencing water mineralization, the overall quality of the groundwater in the CI aquifer for consumption and irrigation usage, and identifies possible chronic health risks for different age groups. To this end, groundwater samples were collected and analyzed for various physicochemical parameters. The assessment tools used include graphical plots, statistical analyses, groundwater pollution index (GPI), nitrate pollution index (NPI), health risk assessment (HRA) model, and irrigation water quality index (IWQI). GPI analysis reveals that 16%, 40%, and 44% of CI aquifer samples are classified with moderate, high, and extremely high pollution, respectively. The NPI method indicates that nitrate pollution levels fall into three categories: moderate (12%), significant (36%), and very significant (49%). HRA results showed that human health risks varied between 3.13 and 10.46 for children, 2.47 and 8.27 for teenagers, and 1.61 and 5.38 for adults, signifying a high risk that spanned all age demographics in the region. Regarding agricultural use, IWQI indicates that water from all studied wells is highly unsuitable for irrigation, potentially harming both soils and plant growth. Hydrochemical analysis by Piper diagram suggested a water type evolution from Na-Cl upstream to Ca–Mg–Cl downstream. Other analytical tools, like Gibbs diagrams, scatter plots, chloro-alkaline indices, saturation indices and multivariate statistical tools, indicated that the hydrochemistry is mainly influenced by interactions with aquifer materials, notably silicate weathering, halite and gypsum dissolution, and cation exchange processes. The study also revealed that the presence of nitrates is primarily attributable to domestic effluents from residential areas. [ABSTRACT FROM AUTHOR]

Groundwater pollution from subsurface leaching of eroded soil, pesticides and fertilizers under agricultural fields are deteriorating the quality of groundwater. In this connection, this study aimed to prepare a groundwater vulnerability map using the DRASTIC (Depth to water table, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media and hydraulic Conductivity) model to evaluate the soil erosion and groundwater quality relationship under soil erosion prone areas of the Panjkora river basin in the northern Pakistan. In this model, relative weights between 1 and 5 are assigned (5 being the most important) to D-R-A-S-T-I-C variables that may affect groundwater quality. According to the results, 72161.64 Hectares (ha) of the study area is low vulnerable to contamination, 144828.70 ha area is slightly moderate vulnerable, 239582.22 ha area is moderate vulnerable, 121769.37 ha area is high vulnerable, and 944.61 ha area is very high vulnerable to groundwater contamination. Groundwater samples from soil erosion hotspots were examined to establish a correlation between soil erosion and groundwater contamination. Total dissolved solids (TDS) and NO2 concentration in some areas were found to be higher than the World Health Organization (WHO) permissible limits. Soil erosion exhibited a positive correlation with groundwater contamination with correlation coefficient (r) of 0.89, root mean square difference (RMSD) of 2.24 and bias of 0.094. The DRASTIC model was validated through ROC AUC curve (score = 0.62). This study is a first attempt to evaluate the inherent groundwater vulnerability and sensitivity to pollution in this region with severely declining groundwater quality due to several unexplored reasons. [ABSTRACT FROM AUTHOR]

Our research project specifically focuses on evaluating groundwater quality in six West Texas counties. We aim to determine whether environmental changes have any impact on the levels of Total Dissolved Solids (TDS) in the water supplied to the public. To achieve this goal, we will be utilizing advanced machine learning algorithms to analyze TDS levels and create geospatial maps for each year between the 1990s and 2010s. To ensure the accuracy of our data, we have gathered information from two trusted sources: the Texas Water Development Board (TWDB) and the Groundwater Database (GWDB). We have analyzed the TDS and other elemental analyses from TWDB–GWDB lab reports and compared them with the quality cutoff set by the World Health Organization (WHO). Our approach involves a thorough examination of the data to identify any emerging patterns. The machine learning algorithm has been successfully trained and tested, producing highly accurate results that effectively predict water quality. Our results have been validated through extensive testing, highlighting the potential of machine learning approaches in the fields of environmental research. Overall, our findings will contribute to the development of more effective policies and regulations in predicting groundwater quality and improving water resource management in Texas. Therefore, this research provides important information for groundwater protection and the development of plans for water resource use in the future. [ABSTRACT FROM AUTHOR]

No single spatial interpolation method reigns supreme for modelling the precise spatial distribution of groundwater quality data. This study addresses this challenge by evaluating and comparing several commonly used geostatistical methods: Local Polynomial Interpolation (LPI), Ordinary Kriging (OK), Simple Kriging (SK), Universal Kriging (UK), and Empirical Bayesian Kriging (EBK). We applied these methods to a vast dataset of 3033 groundwater records encompassing a substantial area (11,100 km2) in the coastal lowlands of the western Netherlands. To our knowledge, no prior research has investigated these interpolation methods in this specific hydrogeological setting, exhibiting a range of groundwater qualities, from fresh to saline, often anoxic, with high natural concentrations of PO4 and NH4. The prediction performance of the interpolation methods was assessed through statistical indicators such as root means square error. The findings indicated that EBK outperforms the other geostatistical methods in forecasting groundwater quality for the five variables considered: Cl, SO4, Fe, PO4, and NH4. In contrast, SK performed worst for the species except for SO4. We recommend not using SK to interpolate groundwater quality species unless the data exhibit low spatial variation, high sample density, or evenly distributed sampling. [ABSTRACT FROM AUTHOR]

Due to the increase in demand for water, the rapid growth of urbanization and industrialization is the main threat to the source and quality of groundwater. The present study aimed to assess the suitability of groundwater for agricultural purposes in coastal regions using integrated approaches such as the saltwater mixing index (SWMI), the mineral saturation index (MSI), the agriculture suitability index (ASI), and unsupervised machine learning (USML) techniques. The result of the SWMI revealed that 20 and 17 sample locations were highly affected by saltwater intrusion in the study region's northern and southeastern parts during the pre- and post-monsoon seasons. The detailed analysis of electrical conductivity in groundwater revealed that 19.64% and 14.29% of the samples were unfit for irrigation purposes, especially five sample locations, during both seasons. Regarding the overall suitability of groundwater for irrigation uses, the ASI values divulged that 8.9% of the samples were unsuitable for irrigation purposes. The spatial analysis of the ASI value indicated that 43.19 and 85.33 sq. km of area were unsuitable for irrigation practices. Additionally, the USML techniques identified the most influenced parameters such as Ca2+, Mg2+, Cl−, and SO42− during both seasons. The present study results help maintain proper, sustainable water management in the study region. [ABSTRACT FROM AUTHOR]

Seawater intrusion seriously threatens the quality of coastal groundwater, affecting nearly 40% of the world's population in coastal areas. A study was conducted in the Kamini watershed situated in the Udupi district of Karnataka to assess the groundwater quality and extent of seawater intrusion. During the pre-monsoon period, 57 groundwater and 3 surface water samples were analyzed to understand the impact of seawater on the groundwater and surface water. The analysis revealed that the groundwater in the study area is slightly alkaline. The weighted overlay analysis map indicated that 11% of the study area is unsuitable for drinking water due to the influence of seawater. The Piper plot analysis revealed that the groundwater is predominantly CaMgCl facies. The hydrogeochemical facies evolution diagram (HFED) showed that 62% of the groundwater is affected by seawater. The HFED and Piper plots also indicate that the surface water is also affected by seawater. These results are also supported by various molar ratios such as Cl− vs. Cl⁻/HCO3⁻, Cl⁻ vs. Na⁺/Cl⁻, Cl− vs. SO42−/Cl−, and Cl⁻/HCO3− vs. Mg2+/Ca2+, suggesting that the majority of the water sample has been affected by seawater. The saturation indices indicated that mineral dissolution has significantly contributed to groundwater salinization. The correlation between sulfate concentration and calcite and dolomite dissolution suggested the influence of seawater intrusion in the coastal aquifer. The process of reverse ion exchange mainly influences the groundwater chemistry according to chloroalkali indices. The total hazard index (THI) values of nitrate and fluoride exceeded limits, posing health risks to adults and children. Studies suggest that with time and space, seawater intrusion is increasing in some pockets of the study area, especially along the west coast. [ABSTRACT FROM AUTHOR]

A complete understanding of groundwater dynamics and its interaction with surface water under the impact of agricultural activities is vital for local agriculture, ecology, and residents of dry regions, which is not commonly recognized in arid areas. This research outlines the geochemical characteristics, recharge sources, and potential factors impacting groundwater quality in a new land reclamation located in the small basin of Abu Mina, which is part of the Western Nile Delta region.1 Thirty-one groundwater samples and two surface water samples were collected in 2021 to represent the Pleistocene aquifer and were subjected to multivariate statistical, hydrochemical, and stable isotope analyses. Data analysis demonstrates that Na+ > Ca2+ > Mg2+ > K+ and SO42– > Cl– > HCO3– > NO3– are the predominant cations and anions, respectively. Groundwater salinity ranged from 465.60 to 6455.18 mg/l, with slightly alkaline. Most of the water samples fall into one of three types of facies: Ca–Cl, Na–Cl, and Mixed Ca–Mg–Cl, in decreasing order. The meteoric genesis index (r2) indicates that deep meteoric water percolation dominates the Pleistocene aquifer. The aquiline diagrams, correlation matrix, and different ionic ratios indicate that evaporation, reverse ion exchange reactions, and the dissolution of carbonate and silicate minerals are the main processes governing groundwater chemistry. Factor analysis (FA) indicated that three factors explain groundwater hydrochemistry, accounting for 71.98% of the total variance. According to the rotating components matrix (F1–F3), the chemistry of the Quaternary aquifer is principally affected by evaporation, ion exchange reactions, and anthropogenic influences. Additionally, salinity increases due to the return flow of irrigation activities and mixing between old and recent water. The stable isotopes (δ18O and δ2H) indicate that the Quaternary aquifer receives groundwater recharge through the return flow of excess irrigation and canal seepage. Under desert reclamation conditions, groundwater salinization processes should be given special consideration. All groundwater samples are appropriate for agricultural irrigation based on the Sodium Adsorption Ratio (SAR), Permeability Index (PI), Percent Sodium (%Na), and Residual Sodium Carbonate (RSC). [ABSTRACT FROM AUTHOR]

Natural springs are one of the potential sources of water supply, but due to negative anthropogenic impacts, the water quality can deteriorate. The Zygmunt Spring in Złoty Potok does not form the basis of the population's water supply, but it is constantly being exploited by residents and tourists. This study was carried out at Zygmunt Spring in two measurement series for 34 physicochemical and bacteriological parameters. The average electrolytic conductivity (EC) of the water in this spring is about 0.039 S · m−1, the pH is about 7.04 and the discharge is equal to 15 dm3 · s−1. The test results were compared with the permissible limits for national drinking water, groundwater quality and WHO standards. The value of the Backman pollution index was calculated for these parameters. This index takes into account parameters that exceed the upper permissible concentrations of contaminants. The Backman Contamination Index value was about -13, but the results of bacteriological analyses indicate a very high number of microorganisms in the water (>300 cfu · mL−1), indicating a high health risk. [ABSTRACT FROM AUTHOR]

The planning and management of water in the river basins require the identification of places where the quality of groundwater is being threatened. The risk of launching the accumulated pollutants present in the solid phase of the soil may be caused by both the changes in the pressure gradients in the aquifers and the changes in the hydrogeochemical balances. In the example of the Ner river valley, into which wastewater from the Łódź agglomeration has been discharged, the factors threatening the chemical status of groundwater were determined. This assessment was carried out based on the results of the determination of the hydrodynamic balance disturbances in the Upper Cretaceous formations, model studies of groundwater flow and hydrogeochemical studies conducted on the sorption complex of the Ner alluvium as well as the chemistry of the river water, alluvial water and groundwater. The results showed that the river water is heavily anthropogenically transformed. Model studies have shown that when the Ignacew -intake wells are pumped collectively, the inflow takes place through the Ner valley, where the hydrogeological window between the Quaternary and the Upper Cretaceous aquifers is found. The withdrawal by the Ignacew intakes may result in the reversal of piezometric pressures in the valley, which creates the possibility of the infiltration of polluted surface water into groundwater. Observations indicate the need to take into account the zones where surface water and water from the river alluvium are a real threat to the chemical status of the aquifers. These aspects are important when determining the protection zones and in renewable and disposal resource assessments of the Main Groundwater Reservoirs. [ABSTRACT FROM AUTHOR]

This study aimed to assess the water quality in the Semel district of Duhok City, Iraq, a key area for agriculture and animal farming. The physical and chemical parameters, including turbidity, pH, electrical conductivity (E.C.), total dissolved solids (T.D.S.), nitrate (NO3-), total alkalinity (T. Al), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), sodium (Na+), potassium (K+), and sulfate (SO-4), were measured in 40 wells, which serve as the primary water source for the region. The results were compared with the World Health Organization (WHO) guidelines to assess compliance and safety. While most physical and chemical parameters were within safe limits, some samples showed elevated levels of NO3-,T. Al, and T.H, exceeding the permissible limits for drinking water. The water quality index (WQI) values ranged from 19.8 to 39.59, classifying all samples as "Excellent" or "Good." The findings underscore the importance of continuous monitoring and management to ensure the safety and sustainability of groundwater in the Semel district. Groundwater resources play a crucial role in meeting the region's water demands, particularly for drinking, irrigation, and other domestic uses. However, the increasing reliance on groundwater necessitates regular assessments to evaluate its quantity and quality. [ABSTRACT FROM AUTHOR]

Under varying flow rate conditions, the transport and retention of polydisperse microplastics (MPls), with an average particle size of 16 ± 6 µm, were investigated in saturated porous media. First-order reversible and irreversible kinetic sorption models were used to describe the sorption kinetics. Sensitivity analyses provided insight into the effects of each sorption parameter. Both numerical modeling and experimental measurements were utilized to evaluate the retention rates of sand filters. The influence of flow rate on sorption was reflected in variations in the distribution coefficient (Kd), the mass transfer coefficient (β), and the irreversible sorption rate (K1). Lower flow rates were associated with higher Kd and β values, indicating increased sorption and reduced mass transfer rates. An increase in Kd resulted in a more gradual sorption process, with a decrease in peak concentration, whereas changes in β had a comparatively smaller impact on sorption rate and peak concentration. Lower K1 values were linked to higher peak concentrations and decreased retention efficiency. Numerical modeling revealed retention rates of 28 ± 1% at a flow rate of 31 mL min−1 and 17 ± 1% at 65 mL min−1. The introduction of MPls into saturated sand environments modifies the transport dynamics within the medium. Consequently, these alterations affect the hydrological characteristics of porous media, impacting groundwater quality and agricultural output. The mean absolute error (MAE) of 6% between the modeled and observed retention rates indicated a high level of accuracy. This study underscores the importance of examining retention efficiency and the accuracy of numerical models in understanding MPl transport in porous media. [ABSTRACT FROM AUTHOR]

The quality and level of groundwater tables have rapidly declined because of intensive pumping in Punjab (Pakistan). For sustainable groundwater supplies, there is a need for better management practices. So, the identification of potential groundwater recharge zones is crucial for developing effective management systems. The current research is based on integrating seven contributing factors, including geology, soil map, land cover/land use, lineament density, drainage density, slope, and rainfall to categorize the area into various groundwater recharge potential zones using remote sensing, geographic information system (GIS), and analytical hierarchical process (AHP) for Punjab, Pakistan. The weights (for various thematic layers) and rating values (for sub-classes) in the overlay analysis were assigned for thematic layers and then modified and normalized using the AHP. The result indicates that about 17.88% of the area falls under the category of very high groundwater potential zones (GWPZs). It was found that only 12.27% of the area falls under the category of very low GWPZs. The results showed that spatial technologies like remote sensing and geographic information system (GIS), when combined with AHP technique, provide a robust platform for studying GWPZs. This will help the public and government sectors to understand the potential zone for sustainable groundwater management. [ABSTRACT FROM AUTHOR]

Groundwater is an important part of water resources, with many characteristics: widespreading, steady changing, good water quality, and usable. Therefore, it is an ideal drinking water source. However, with the rapidly economic development and the accelerated urbanization process, the problem of groundwater pollution has become increasingly serious. In this study, the eastern part of Yongning County was taken as the study area, 30 groundwater samples from 1997 to 1998, 2007 to 2008, and 2017 to 2018 were selected for water quality assessment and health risk assessment. The results showed that the groundwater chemical type had a tendency to change from HCO3‐Ca·Mg type to SO4·Cl‐Ca·Mg type, and the rock weathering was the important factor controlling the groundwater hydrochemistry in the eastern part of Yongning County. The water quality evaluation of Mn and As was grade II, and the water quality evaluation of Cu, Zn, Cr6+, Cd, and Mo was grade I. Both carcinogenic and non‐carcinogenic risks were higher in children than in adults, the acceptable frequency of adults was higher than that of children, and the area with higher risks was distributed in the central and easternmost regions of Yongning County. As was a more sensitive factor to carcinogenic risk than Cr6+. Therefore, we should pay more attention to the governance of As and the health of children's drinking water. Special attention also should be paid to the water environment protection in the eastern parts of Yongning County. Water quality assessment and health risk assessment in the study area lay a foundation for water pollution control and water environmental protection in the future. Practitioner Points: The hydrochemical type changes from HCO3‐Ca·Mg type to SO4·Cl‐Ca·Mg type, which is mainly affected by rock weathering.According to the Bayesian water quality assessment: Mn and As was II, and Cr belongs to I is small.As was the main carcinogenic factor, Mn was the main non‐carcinogenic factor, and the risk was higher in children than adults. [ABSTRACT FROM AUTHOR]

Long-term application of organic and inorganic fertilizers increases the possibility of contamination of greenhouse soils with heavy metals. This study investigated heavy metals (Cd, Co, Cu, and Zn) adsorption-desorption under mono and competitive systems in 10 soils from agricultural and greenhouse soils in western Iran. In most of the studied soils, the values of the Freundlich distribution coefficient (Kf) of Cu were higher than other heavy metals, indicating that Cu is maintained by the soils stronger than Cd, Co, and Zn. Based on the average Kf, the selectivity sequence of heavy metals in agricultural and greenhouse soils was ordered as Cu > Zn > Cd > Co in both mono and competitive systems. In general, greenhouse soils had lower Kf for heavy metals compared with agricultural soils, indicating the vulnerability of greenhouse soils to heavy metals leaching. In desorption experiments, the percentage of heavy metal desorption increased as the concentration of added heavy metals increased in both systems (except Cu in the mono-heavy metal system). The findings revealed that continuous vegetable production and the application of organic and inorganic fertilizers in these greenhouse soils may cause changes in soil properties and heavy metal mobility, posing hazards to human health and groundwater quality. [ABSTRACT FROM AUTHOR]

Groundwater is one of the most vital sources of irrigation in semi-arid regions of India, and in Punjab, India this resource is being highly exploited due to intensive agricultural practices. In the present study, groundwater quality in Bathinda district of Punjab, India was evaluated to know its suitability for drinking and human health risk associated with direct use of groundwater. To examine the suitability of groundwater for drinking purposes, drinking water quality index (DWQI) approach was used. Non-carcinogenic human health risk associated with the presence of fluoride and nitrate in groundwater was evaluated for the adults and children, through dermal and oral ingestion exposure pathways. Further, to know the processes governing the aquifer geochemistry, Gibbs plot, interionic relationships and principal component analysis were carried out. The results of the present investigation revealed that quality in 73% groundwater samples was not suitable for direct consumption. The results of hazard index (HI) indicated that 91% samples in case of men and 95% samples in case of women and children have HI value more than 1. There is a high non carcinogenic human health risk potential due to direct use of groundwater, and children and women are more prone to this risk. The inter-ionic relationships exhibited that evaporation processes due to semi-arid hot type climate, silicate weathering, shallow groundwater level, interaction of canal and ground water along with the agricultural return flow mainly controlled the groundwater chemistry in the area under investigation. [ABSTRACT FROM AUTHOR]

Groundwater contamination from non-engineered landfills has been extensively documented. However, there is a gap in extensive field research regarding whether engineered landfills can also contribute to groundwater contamination. We selected 62 engineered municipal landfills in Eastern China and collected both leachate samples from the landfills and groundwater samples from nearby wells. Through the analysis of inorganic solute indicators in both groundwater and leachate samples, we explored the impact of landfill leachate on the inorganic solute composition of groundwater. Our findings revealed that over half of the groundwater samples surrounding the landfill sites exceeded recommended drinking water limits for inorganic solutes. The correlation analysis demonstrates a significant relationship between Cl−, SO42−, Na+, and K+ levels in leachate and groundwater, highlighting the direct impact of landfill activities on groundwater quality. Moreover, specific characteristics of the landfill, such as its age, the total waste volume, and geographic location, were found to influence the inorganic solute composition in the groundwater. This effect was apparent in the positive correlations between the age of the landfill and NH3-N, Ca2+, and Mg2+ levels in groundwater, the total waste volume of the landfill and Ca2+ content in groundwater, and the latitude of the landfill and Cl− and HCO3− concentrations in groundwater. This work carries implications for assessing environmental risks associated with engineered landfills and enhancing landfill design, management, and monitoring practices. [ABSTRACT FROM AUTHOR]

This study investigated groundwater in the central Rif region of northern Morocco by analysing 55 water sampling points to assess its physicochemical and hydrogeochemical properties. Through hydrochemical analysis, GIS spatial exploration, and multivariate statistical analysis, a direct correlation was found between EC, TDS, and major ions, influencing overall water mineralization. The key findings included pH levels ranging from 6.10 to 8.52, EC from 828 to 4581 μS/cm, and varying concentrations of Ca2+, Mg2+, Na+, K+, HCO2–, Cl–, N–NO2–, and SO42–. Notably, TDS and TH ranged from 647.19–3609.36 mg/L and 64.23–1051.24 mg/L, respectively, with a significant portion of samples exceeding WHO guidelines, particularly chloride (61.81%), sulfate (92.72%), and nitrate (12.72%) samples. The Piper diagram highlights sodium chlorides (Na–Cl) as the predominant chemical facies (70.9%), while the Gibbs diagram emphasizes the impact of evaporation on water chemistry dynamics. This study revealed the complex influence of geological and anthropogenic factors on groundwater quality, potentially leading to seawater intrusion in coastal aquifers. The observed high mineralization and hardness levels, in addition to mild alkalinity, pose public health risks, underscoring the need for continuous monitoring and sustainable management practices in coastal groundwater management to protect human health and the environment. [ABSTRACT FROM AUTHOR]

Groundwater quality can be impacted by the backfilling of coal pits with waste rock containing new mineral surfaces and nanomaterials. This study was implemented to identify newly available arsenic and selenium sources in waste rock from the Cordero Rojo Mine in the Powder River Basin, Wyoming, to highlight the alteration of contaminant sources with the transition from an overburden geologic state to the mined waste rock. Basic kinetic models were constructed to replicate the possible weathering modeling scenario derived from published sources of arsenic and selenium in the Powder River Basin overburden—pyrite and gypsum, respectively. These basic prediction models were unable to capture the arsenic and selenium trends recorded for a saturated column loaded with waste rock from the Cordero Rojo Mine. Enhanced kinetic models were tested through trial and error to capture newly available sources created by the mining of the waste rock. The incorporation of new source contributions produced modeled arsenic and selenium trends similar to the observed trends in water extracted from the column. The identification of newly available contaminant sources in backfill waste rock is necessary to evaluate the potential release of contaminants and the exceedance of water quality criteria for overburden formations that have not previously shown the potential for water quality contamination. [ABSTRACT FROM AUTHOR]

Groundwater contamination poses a severe public health risk in Lahore, Pakistan's second-largest city, where over-exploited aquifers are the primary municipal and domestic water supply source. This study presents the first comprehensive district-wide assessment of groundwater quality across Lahore using an innovative integrated approach combining geographic information systems (GIS), multi-criteria decision analysis (MCDA), and water quality indexing techniques. The core objectives were to map the spatial distributions of critical pollutants like arsenic, model their impacts on overall potability, and evaluate targeted remediation scenarios. The analytic hierarchy process (AHP) methodology was applied to derive weights for the relative importance of diverse water quality parameters based on expert judgments. Arsenic received the highest priority weight (0.28), followed by total dissolved solids (0.22) and hardness (0.15), reflecting their significance as health hazards. Weighted overlay analysis in GIS delineated localized quality hotspots, unveiling severely degraded areas with very poor index values (>150) in urban industrial zones like Lahore Cantt, Model Town, and parts of Lahore City. This corroborates reports of unregulated industrial effluent discharges contributing to aquifer pollution. Prospective improvement scenarios projected that reducing heavy metals like arsenic by 30% could enhance quality indices by up to 20.71% in critically degraded localities like Shalimar. Simulating advanced multi-barrier water treatment processes showcased an over 95% potential reduction in arsenic levels, indicating the requirement for deploying advanced oxidation and filtration infrastructure aligned with local contaminant profiles. The integrated decision support tool enables the visualization of complex contamination patterns, evaluation of remediation options, and prioritizing risk-mitigation investments based on the spatial distribution of hazard exposures. This framework equips urban planners and utilities with critical insights for developing targeted groundwater quality restoration policies through strategic interventions encompassing treatment facilities, drainage infrastructure improvements, and pollutant discharge regulations. Its replicability across other regions allows for tackling widespread groundwater contamination challenges through robust data synthesis and quantitative scenario modeling capabilities. [ABSTRACT FROM AUTHOR]

Groundwater represents a critical resource for sustaining the livelihoods of both urban and rural populations, facilitating economic and social development, and preserving ecological equilibrium. This study leverages groundwater quality monitoring data from the northern Baiquan spring basin (NBSB) to elucidate groundwater hydrochemical characteristics and decipher the temporal variability in water quality. Findings suggest that groundwater within the NBSB is predominantly weakly alkaline and characterized as hard-fresh, with HCO3− and Ca2+ as the predominant ions, which collectively demarcate the hydrochemical type as predominantly HCO3-Ca. The principal constituents of NBSB groundwater are influenced predominantly by the weathering of carbonates and silicates alongside the dissolution of gypsum and halite. Moreover, agricultural operations and similar human activities have exerted an impact on the hydrochemical attributes of NBSB's groundwater. Generally, fluctuations in groundwater anion concentrations over time are more pronounced than those of cations, exemplified by a significant upward trend in the major ion concentrations at the BQ03 monitoring site in the later stages. While the general groundwater quality within the NBSB is deemed satisfactory, most monitoring sites have experienced an escalation in water quality indices over time, notably at BQ03, which warrants serious attention. The findings of this research contribute to the efficient management and sustainable utilization of groundwater resources in the NBSB. [ABSTRACT FROM AUTHOR]