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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 3 -Mg and HCO 3 -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. [ABSTRACT FROM AUTHOR]

Understanding the seasonal variations in the landfill leachate plumes (LLPs) properties and complex connections between concentrations of leachate variability, and its environment is essential for environmental and public health management. This study explores the combined electrical resistivity (ER) data and physiochemical water analysis (PWA) coupled with the excavations to monitor the landfill physiochemical properties (LPPs) due to seasonal variations and their implications on environmental vital organs and public health. The variations in ER and LLP distributions across the overburdened top layer due to seasonal changes were examined. The low ER contrasts were encountered within the ranges of 1.5 Ωm – 19.0 Ωm which was mapped as LLP accumulated zones within the landfill, while high ER values varied between 15 Ωm – 260 Ωm off-the landfill extending beyond 15 m. The results of the PWA indicate high concentrations of heavy metals (HMs) such as iron (Fe), lead (Pb), zinc (Zn), and cadmium (Cd) decreasing with wet seasons and increasing with dry seasons. The overall high concentration of HMs in the LLPs was indeed varied between 9.81 ± 2.15–19.07 ± 3.68, while the electrical conductivity (EC) significantly increased from 17.99 ± 1.92 mg/L to 24.87 ± 3.31 mg/L towards the wet season. The increment and decrement encountered in the LPPs are due to seasonal variation and dilution. The order of decrement in the HMs in the LLPs treads as follows EC > Fe > Zn > Pb > Cd in values, respectively. The near-surface EC aligned well with the ER results and boundaries of the waste disposal site, which was verified by the soil excavations. In addition, the ER method was extended beyond the landfill for adequate monitoring, identifying the subsurface layers, conductive shallow zones mapped as the zones of LLP accumulation, resistive deep and shallow zones mapped as the consolidated lateritic topsoil and crystalline basement rocks in some cases, and a dipping conductive lineament zones identified as fracture zones just before the crystalline basement. In conclusion, the ER technique reveals the vertical and horizontal extents of the LLP escapade, the PWA expressed the concentrations of HMs in the LLPs, heightening the implications on the environmental and human health. Finally, the combined techniques deployed for monitoring the physiochemical properties of LLPs due to seasonal variation and the impacts on the integrity of groundwater quality systems and public health inform sustainable waste management practices, which contributes significantly to the protection of groundwater resources and the development of effective strategies to safeguard groundwater systems and public health for present and future generations. [ABSTRACT FROM AUTHOR]

In groundwater modeling studies, accurate spatial and intensity identification of water sources and sinks is of critical importance. Precise construction data about wells (water sinks) are particularly difficult to obtain. The collection of well log data is expensive and laborious, and government records of historic well log data are often imprecise and incomplete with respect to the precise location or pumping rate. In many groundwater modeling studies, such as groundwater quality assessments, a precise representation of the horizontal and vertical distribution of well screens is required to accurately estimate contaminant breakthrough curves. The number of wells under consideration may be very large, for example, in the assessment of nonpoint source pollution. In this paper, we propose an imputation framework that allows for proper reconstruction of missing well data. Our approach exploits available information and tolerates data gaps and imprecisions. We demonstrate the value of this method for a subregion of the Central Valley aquifer (California, USA). We show that our framework imputes missing values that preserve statistical properties of available data and that remain consistent with the known spatial distribution of well screens and pumping rates in the three‐dimensional aquifer system. [ABSTRACT FROM AUTHOR]

The Arab region is located in an arid environment and suffers from water scarcity and poor water quality which are expected to become more severe in coming years due to global warming. In this study, the groundwater quality of 205 wells in Qatar was investigated. The physical parameters of pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, inorganic carbon (IC), and organic carbon (OC) were determined. The study characterized the concentrations of major anions of Cl, F, Br, NO3, PO4, and SO4, and major cations of Ca, K, Mg, and Na. Importantly, metals and metalloids including V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Pb, and U were determined. The results revealed that the groundwater of all wells is not drinkable due to high salinity (average TDS 4598 mg/L and salinity 0.4%, respectively). Additionally, average concentrations of major anions Cl, SO4, and F were 1472, 1064, and 1.9 mg/L, respectively, and all exceed the World Health Organization (WHO) guidelines for drinking water. However, NO3 concentration in 11 out of 205 wells was above the WHO guidelines of 50 mg/L due to intensive agriculture and fertilizer applications. Major cations of Ca, K, Mg, and Na were higher than WHO guidelines with average concentrations of 345, 63, 127, and 923 mg/L, respectively. All trace metals were much lower than the WHO guidelines for drinking water; however, the vanadium (V) average concentration in groundwater of all wells was 31 μg/L, which is five times higher than the Dutch guidelines (whereas the WHO has no guidelines for V). The groundwater of Qatar is dominated by Ca and Mg sulfates in Sabkha environments and dominated by NaCl in the coastal zones from evaporate environments consisting of coastal salt flats, salt pans, estuaries, and lagoons supersaturated by salts and the influence of sea water intrusion. [ABSTRACT FROM AUTHOR]

Citizen science (CS) around the world is undergoing a resurgence, potentially due to the utilization of new technologies and methods to capture information, such as data and photo entry via mobile phone apps. CS has been used in aquatic ecology for several decades, however the use of volunteers to collect data in groundwaters has rarely occurred. Groundwater research, particularly groundwater ecosystems, is unevenly distributed across the world, limiting our knowledge of these ecosystems and their functions. Here, we engaged six volunteer farmers in semi‐arid region of north‐western New South Wales, Australia to participate in an assessment of groundwater health using privately owned wells. Volunteers were supplied with sampling kits and instructions on sampling methods. Data retrieved indicated the health of the groundwater ecosystems, simultaneously providing information on water quality and groundwater biota present within the farm aquifers. Diverse stygofauna were collected from the trial, which reflected historical records of stygofauna within the same catchment indicating the viability of using citizen scientist for data collection. The citizen science project not only aided the collection of data and assessment of groundwater health, but also provided a tool for education, attracting media attention which furthered the education to a national audience. The amount of data still required to understand groundwater ecosystems, combined with the urgency to manage these environments, suggests that citizen scientists may complement the efforts of scientists around the globe to establish the impacts and consequences of human activities on this resource. [ABSTRACT FROM AUTHOR]

The presence of mineral pollutants, combined with bacterial contamination, has significantly impacted groundwater quality and led to various health-related issues in mining-impacted areas. Therefore, we measured the concentration of fluoride (F-), phosphate (PO43-), sulphate (SO42-), ammonium (NH4+), nitrate (NO3-), the total coliforms (TCs), and physiochemical characteristics in groundwater samples of South Khorasan, Eastern Iran. For this, we collected water samples from 100 wells in spring and autumn across this mining-impacted area. We then measured the concentrations of mineral pollutants and assessed their associated health risks to children and adults using the Environmental Protection Agency (EPA) models and spatiotemporal zoning maps in ArcGIS. The concentrations of PO43-, NH4+, SO42-, NO3-, and F- were 0.70 ± 0.34, 0.82 ± 0.9, 175.45 ± 123, 15.26 ± 9.41, and 0.53 ± 0.68 mg/L in spring, and 0.71 ± 3.18, 4.68 ± 31, 306.72 ± 615.80, 19.30 ± 15.61, and 0.72 ± 0.65 mg/L in autumn, respectively. PO43-, NH4+, and SO42- exceeded both the World Health Organization (WHO) and EPA, but NO3- exceeded only EPA standards. TCs in both seasons exceeded the standards set by the EPA and WHO. The hazard quotient (HQ) values indicated non-carcinogenic risks for F⁻ and NO3⁻, while posing no risks NH4⁺ and PO43⁻ in both adults and children during autumn and spring.Hazard index (HI) was greater than 1 for all minerals in both children and adults in autumn and spring. No correlation was observed between mineral compounds and TCs in the study area, yet the water samples were highly contaminated by coliform with a significant risk to adults and children. In essence, both mineral pollutants and TCs potentially pose serious risks to human, and more efforts are required to improve the quality of water in this area. [ABSTRACT FROM AUTHOR]

Groundwater is an essential natural resource for mankind. Due to various geogenic and anthropogenic causes, groundwater quality has raised serious concern over the years. In this study, groundwater quality was evaluated for its suitability for irrigation in the Jorhat and Golaghat Districts of Assam, India. A total of 100 groundwater samples were collected from shallow aquifers (< 35 m) from different locations during the pre-monsoon season (March–April 2022). Groundwater in the study area is slightly alkaline in nature (mean pH value of 7.44). The average cations and anions chemistry are in the order of Na+ > Ca2+ > Mg2+ > K+ and HCO3− > Cl− > SO42− > CO32−, respectively. Ca-Mg-HCO3 followed by Na-Ca-HCO3-Cl are the primary water types in the study area. Pearson's correlation matrix showed a positive correlation between TDS and EC (r = 0.78) and sodium showed a positive correlation with TDS and bicarbonate (r = 0.62 and r = 0.65), respectively. Gibbs plot indicated that rock-water interaction is the dominant factor that controls the chemistry of the groundwater of the area. Irrigation parameters like Sodium Absorption Ratio (SAR), Permeability Index (PI), Magnesium Absorption Ratio (MAR), Kelly's Ratio (KR), and Irrigation Water Quality Index (IWQI) indicated that groundwater is overall suitable for irrigation. USSL diagram illustrated that most of the samples fell into the C2 (medium salinity) and S1 (low sodium hazard) categories. Wilcox plot showed the samples fell in excellent to good categories indicating fitness of groundwater for irrigation in the area. [ABSTRACT FROM AUTHOR]

Groundwater quality degradation is a significant environmental issue worldwide, with potentially severe economic consequences and harm to ecosystems and biodiversity. This can directly affect human health, particularly in developing countries where rapid and uncontrolled urbanization is on the rise. Groundwater is the primary resource for meeting the water needs of the Eloued region, located in southeastern Algeria. Water is considered unfit for human consumption if its physico-chemical elements exceed national or international standards or guidelines. We used the GPI and SPI indices to evaluate the quality of groundwater suited for drinking. Groundwater samples were obtained from 22 wells at depths of more than 250 m. Standard analytical procedures were used to determine the physicochemical characteristics of the collected samples, which included pH, EC, TDS, Na+, Ca+2, Mg+2, K+, Cl−, HCO3−, SO4−2, NO3−, NO2−, NH4+ and PO4−3. Multivariate statistical analysis and GIS techniques were used to process the results. The results of the selected physicochemical parameters were compared with World Health Organization (WHO) guidelines to determine the quality of drinking water. The findings indicate that the waters of the terminal complex aquifer are salty and contain medium to high quantities of main ions that surpass the established drinking water limits. The primary ions' relative abundance is Cl− > SO4−2 > HCO3− > NO3 for anions and Na+ > Ca+2 > Mg+2 > K+ for cations. Groundwater chemical types were dominated by Na+, Ca+2, Cl−, and SO4−2. Principal Component Analysis (PCA) showed that alteration and dissolution of carbonates, evaporates, salts, partly silicates, and evaporation, are the main reasons affecting the chemical composition of water in Eloued. The GPI results show that 18.18%, 54.54%, and 27.27% of the water samples were classed as lightly polluted, moderately polluted, or substantially polluted for drinking purposes, respectively. According to the SPI study, 9.09%, 36.36%, 36.36%, and 18.18% were considered drinkable, mildly contaminated, moderately polluted, and seriously polluted for drinking purposes, respectively. According to the GPI and SPI models' geographical distribution maps, potable water is generally scarce and concentrated in the northeastern section of the research area, near the town of Ourmes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

El Qaa plain is one of the promising areas for agriculture projects, owing to its soil and groundwater resources. So, 14 groundwater samples were collected, chemically analyzed, hydrochemical (ratios, models and plots) and GIS techniques were applied, to evaluate the factors governing this water chemistry and suitability for irrigation. The results indicated the expansion of the agricultural area 8 times in the last 2 decades. The water can be divided into two groups; (A) freshwater (TDS ≤ 1000) in the eastern part of the study area within the clastic weathered basement rocks part of the aquifer, and (B) saline water (TDS > 1000) in the western part within the carbonates and evaporites rich sediments and close to the Gulf of Suez. The deduced factors controlling groundwater chemistry were precipitation, evaporites dissolution, seawater intrusion and ion exchange process. The calculated sodium absorption ratio (SAR) was < 10 indicating the good quality of this water for irrigation without sodicity hazard. Water of Group (A) (electric conductivity < 2250µS/cm) can be used safely for irrigation without any impact of salinity on all types of soil and plants. Group (B) water (electric conductivity > 2250µS/cm) has salinity hazard and can be used for irrigation on well-permeable soils and salt-tolerant plants. The concentrations of the studied potentially toxic elements (PTEs) were within the permissible limit for irrigation. Expansion in agricultural activities has adverse impact on groundwater quality. So, eco-friendly fertilizers should be applied in this promising area with the application of hydrologic pumping advises to safe aquifer quality from the degradation. [ABSTRACT FROM AUTHOR]

The Oum Er-Rbia watershed faces a critical challenge in effectively disseminating the results of groundwater and surface water quality assessments to stakeholders and the public. This research aimed to address this challenge by developing a method for synthesizing and visualizing knowledge through web mapping. The methodology followed involved collecting data on surface and groundwater quality, hydrogeology, human impact, and topography. Subsequently, a needs analysis was conducted to identify the requirements of potential users (land managers, water users, researchers) to de- fine system functionalities. Spatial data was organized into thematic layers (e.g., hydrography, geology) with detailed attributes to address user queries and generate maps. Open-source technologies were employed to build a web-based system (SCIEM) allowing users to visualize, analyze, and explore water quality data. Finally, user evaluation confirmed SCIEM's effectiveness in disseminating and analyzing water quality information within the watershed. The developed web mapping system has successfully addressed the challenge of disseminating research results by establishing an online, interactive multi-scale mapping system for groundwater and surface water characterization. This system facilitates the presentation of maps with a simple click, making them accessible to both geospatial experts and non-specialists. As a result, stakeholders such as water managers, land-use planners, and even farmers and citizens can now access a comprehensive view of groundwater and surface water information. Additionally, the utilization of free and open-source software has proven to be a cost-effective and efficient approach. The interactive multi-scale mapping system (IMSMS) provides a valuable tool for disseminating water quality data within the Oum Er-Rbia watershed. Building on this success, future research can explore the potential of adapting the IMSMS framework to other regions facing water quality challenges. Additionally, incorporating new data types beyond water management could provide a more holistic understanding of the interconnected factors influencing water resources. [ABSTRACT FROM AUTHOR]

The aim of the study was to analyse precipitation, subsurface runoff and concentrations of nutrients in water (NH4 +- -N, NO3 --N and PO4 3- ions). The study was conducted at the lysimetric station in Jaworki (Małe Pieniny, Nowy Targ district, Malopolska province, 600 m a.m.s.l.). Measurements were carried out during vegetation periods, from April to September. The paper consists of an analysis of data in two periods - 2001-2018 and 2019-2022. Data in the historical years (2001-2018) showed that water quality as well as its quantitative variability was low, mainly until 2015. The year 2018 indicated slow changes in this regard. Analysis of the years 2019-2022 indicated that the outflow was almost identical. The years 2019 and 2022 were characterized by significantly higher leachate concentrations. Ammonium ion contents were similar. Analysis of nitrate ions in leachate showed an increasing trend over the years. Phosphates, on the other hand, showed a similar trend to nitrate ions. The study showed which types of land use have the greatest impact on both subsurface runoff volume and leachate water quality. In mountainous conditions, the type of use, as well as the climate and soil, have an extremely significant impact on the volume and quality of runoff, which affect the quality of groundwater and surface water. [ABSTRACT FROM AUTHOR]

Groundwater analysis across the Oum Rbia watershed is currently hampered by technical constraints and high costs. This research aimed to produce comprehensive groundwater quality maps throughout the basin aquifers by integrating the water quality index (WQI) and microbiological quality index (MQI) with GIS-Pro for a spatiotemporal assessment of water quality. Twenty physicochemical parameters, including pH, temperature, conductivity, total dissolved solids, permanganate index, ammonium (NH4+), major cations (Na+, K+, Ca²+, Mg²+, Mn²+), major anions (Cl-, HCO3-, NO2-, NO3-, CO3²-, SO4²-), total hardness (TH), total alkalinity (TAC), and total iron (FeT) concentration were analyzed. Additionally, the microbiological parameters, such as the fecal streptococci, fecal coliforms, and total coliforms were investigated. Fieldwork conducted over twelve campaigns during the 2021 and 2022 seasons involved sample collection from fifty-four locations across the six aquifers of the watershed. The comprehensive database facilitated the calculation of both MQI and WQI. Kriging interpolation was utilized to create spatial estimates of these indices beyond the sampling points, enabling the generation of maps that visualize water quality across the study area. WQI indicated that groundwater in most of the studied basin is of excellent quality, though water quality deteriorates in the areas receiving wastewater discharge from urban, industrial, and agricultural activities. The MQI results revealed significant pathogenic germ contamination across a substantial portion of the watershed, intensifying during the summer due to such factors as temperature, river flow, human activities, and seasonal pollution sources. These maps enhance the understanding of water table information for non-experts as well as aid decision-makers in identifying critical areas and developing effective management strategies. However, complexities in water quality and training data influence the accuracy of ArcGIS-Pro predictions, potentially overlooking key factors if the data is insufficient. [ABSTRACT FROM AUTHOR]

In response to the global issue of water scarcity exacerbated by climate change, this study investigates the physicochemical properties of water resources within the Algerian hydrographic basin. Despite efforts to develop groundwater sources for drinking water, contamination risks from nearby agricultural and industrial activities remain significant. To address this, the study focuses on characterizing these water sources, particularly noting elevated levels of nitrates and manganese ions beyond acceptable limits. Despite the negative correlation between manganese and nitrate ions, we have modeled complexes containing both and compared them with others to assess their chemical and biological activities. This integrated approach allows us to understand complex ion interactions and propose innovative solutions for managing water resources more effectively. Through our work, we aim to contribute to the development of sustainable water management strategies, bridging the gap between theoretical modeling based on Density Functional Theory and practical applications. By combining empirical data with theoretical insights, we aspire to offer comprehensive solutions for mitigating water contamination and ensuring access to clean drinking water for communities in the Algerian hydrographic basin. [ABSTRACT FROM AUTHOR]

This study incorporated hydrogeochemical facies, the entropy-weighted water quality index (EWQI), multivariate statistics, and probabilistic human exposure assessment to investigate hydrogeochemistry, analyze groundwater quality, and estimate potential risks to human health in a lithium-rich ore area (Jadar River basin, Serbia). The findings designated the Ca·Mg-HCO3 hydrogeochemical type as the predominant type of groundwater, in which rock weathering and evaporation control the major ion chemistry. Due to the weathering of a lithium-rich mineral (Jadarite), the lithium content in the groundwater was very high, up to 567 mg/L, with a median value of 4.3 mg/L. According to the calculated EWQI, 86.4% of the samples belong to poor and extremely poor quality water for drinking. Geospatial mapping of the studied area uncovered several hotspots of severely contaminated groundwater. The risk assessment results show that groundwater contaminants pose significant non-carcinogenic and carcinogenic human health risks to residents, with most samples exceeding the allowable limits for the hazard index (HI) and the incremental lifetime cancer risk (ILCR). The ingestion exposure pathway has been identified as a critical contaminant route. Monte Carlo risk simulation made apparent that the likelihood of developing cancerous diseases is very high for both age groups. Sensitivity analysis highlighted ingestion rate and human body weight as the two most influential exposure factors on the variability of health risk assessment outcomes. [ABSTRACT FROM AUTHOR]

Over the last decades, as a consequence of wastewater discharges and other anthropogenic sources, severe nitrate (NO3−) pollution has developed in municipal environment causing global concern. Thus, eliminating the potential sources of pollution is one of the major challenges of the twenty-first century, whereby sanitation services are essential for ensuring public health and environmental protection. In the present study, long-term monitoring (2011–2022) of shallow groundwater NO3− contamination in municipal environment was carried following the construction of the sewerage network (2014) in the light of the pre-sewerage situation. Our primary aim was to assess the long-term effects of sewerage on nitrate NO3− levels in the shallow groundwater and evaluate the efficiency of these sanitation measures over time. Based on the results, significant pollution of the shallow groundwater in the municipality was identified. During the pre-sewer period, NO3− concentrations exceeded the 50 mg/L limit in the majority of monitoring wells significantly, upper quartile values ranged between 341 and 623 mg/L respectively. Using Nitrate Pollution Index (NPI) and interpolated NO3− pollution maps, marked spatial north–south differences were detected. In order to verify the presence of wastewater discharges in the monitoring wells, the isotopic ratio shifts (δ) for 18O and D(2H) were determined, confirming municipal wastewater effluent. Variations in NO3−/Cl− molar ratios suggest also contamination from anthropogenic sources, including septic tank effluent from households and the extensive use of manure. Data series of 7 years (2015–2022) after the investment indicate marked positive changes by the appearance of decreasing trends in NO3− values confirmed by Wilcoxon signed rank test and ANOVA. By comparing the pre- and post-sewerage conditions, the mean NO3− value decreased from 289.7 to 175.6 mg/L, with an increasing number of monitoring wells with concentrations below the limit. Our results emphasise the critical role of sanitation investments, while also indicating that the decontamination processes occur at a notably slow pace. Detailed, long-term monitoring is therefore essential to ensure accurate follow-up of the ongoing changes. The results can provide information for local citizens and authorities to improve groundwater management tools in the region. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Like many small island communities, the U.S. Virgin Islands (USVI), an unincorporated territory of the U.S., is naturally freshwater scarce. In recent decades, rapid land development in the USVI has increased water demand considerably, exerting extra pressure on freshwater resources. Freshwater quantity and quality data for the USVI are very scarce and scattered, which limits freshwater management capabilities. We draw attention to this information deficit and discuss its implications by reviewing the current state of knowledge of surface and groundwater quantity and quality for the USVI. Our review confirms that long‐term records of surface and groundwater quantity and quality are limited and unreliable. For example, streamflow was most recently monitored in 2006, and the most extensive surface water quality records are from the 1960s and 1980s. Since 2016, mean groundwater levels have been recorded daily, but only for three wells (one on each island of the USVI). Importantly, this lack of information threatens water security for the territory and limits our understanding of how development has impacted water quality and availability over time. This could be addressed using models, such as a groundwater recharge model, in combination with remote sensing and updated field data (i.e., streamflow, groundwater, and ecohydrological characterizations of land use change). [ABSTRACT FROM AUTHOR]

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]

Artificial objects, particularly tunnels used for water transport under pressure, impact the geological and hydrogeological environment to a greater or lesser extent, and it is vital to assess their contributions to groundwater quality. Although tunnels are typically lined with concrete, their interaction with the hydrogeological environment intensifies over time. In this study, the detailed spatiotemporal monitoring of all hydrogeological features within the potential influence zone of the hydraulic tunnel of the Pirot Hydropower Plant has been conducted in order to determine the degree of interaction between the artificial object and the natural environment in real time, and to assess the correlation between monitored parameters. Natural conditions of the environment were defined, as well as potential changes through the observing groundwater regimes. The monitoring network included observations of groundwater regimes at seven springs located in close proximity to the hydraulic tunnel, within the tunnel, at three piezometers, and along the river, while methods employed were hydrological monitoring, physicochemical monitoring, and groundwater piezometer sensing. Cross-correlation analysis has been applied for assessing the impact of precipitation dynamics on the spring discharge regime. The results indicate a direct influence of the tunnel on the hydrogeological environment, proving the consistency and high correlation between the monitored parameters. [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]

Groundwater is becoming increasingly important as surface water is decreasing and becoming more and more polluted. In particular, rural areas in the arid region of Central Asia face problems with both water quantity and quality. In view of this, we investigated the drinking water quality in the Maysky district in the Pavlodar region, Kazakhstan. The organoleptic properties, together with microbiological indicators, as well as organic and inorganic substances of drinking water before and after treatment, and tap water were studied and compared to recommended levels. The bacteriological indicators of the drinking water, especially, showed that the water represents health risks since the presence of bacteria of the genus Pseudomonas aeruginosa was confirmed. Water treatment reduced the total microbial count (TMC) indicator by 3.6 times. However, TMC still exceeded permissible levels in the tap water, indicating that the drinking water is sanitary and epidemiologically not acceptable. Pathogenic contamination of drinking water can severely affect weaker individuals and children. It has been estimated that the infant mortality rate in Kazakhstan is six times higher as compared to the EU and less than 30% of Kazakhstan's population have access to safe water. Also, 50% of the population drink water that does not comply with the international standards, e.g., bacteriological levels. Thus, it is important to continuously monitor the groundwater quality to minimize health risks and work towards access to safe drinking water, in line with the UN SDGs. [ABSTRACT FROM AUTHOR]

Water is a vital resource, and its quality has a direct impact on human health. Groundwater, as one of the primary water sources, requires careful monitoring to ensure its safety. Although manual methods for testing water quality are accurate, they are often time-consuming, costly, and inefficient when dealing with large and complex data sets. In recent years, machine learning has become an effective alternative for water quality assessment. However, current approaches still face challenges, such as the limited performance of individual models, minimal improvements from optimization algorithms, lack of dynamic feature weighting mechanisms, and potential information loss when simplifying model inputs. To address these challenges, this paper proposes a hybrid model, BS-MLP, which combines GBDT (gradient-boosted decision tree) and MLP (multilayer perceptron). The model leverages GBDT's strength in feature selection and MLP's capability to manage nonlinear relationships, enabling it to capture complex interactions between water quality parameters. We employ Bayesian optimization to fine-tune the model's parameters and introduce a feature-weighting attention mechanism to develop the BS-FAMLP model, which dynamically adjusts feature weights, enhancing generalization and classification accuracy. In addition, a comprehensive parameter selection strategy is employed to maintain data integrity. These innovations significantly improve the model's classification performance and efficiency in handling complex water quality environments and imbalanced datasets. This model was evaluated using a publicly available groundwater quality dataset consisting of 188,623 samples, each with 15 water quality parameters and corresponding labels. The BS-FAMLP model shows strong classification performance, with optimized hyperparameters and an adjusted feature-weighting attention mechanism. Specifically, it achieved an accuracy of 0.9616, precision of 0.9524, recall of 0.9655, F1 Score of 0.9589, and an AUC score of 0.9834 on the test set. Compared to single models, classification accuracy improved by approximately 10%, and when compared to other hybrid models with additional attention mechanisms, BS-FAMLP achieved an optimal balance between classification performance and computational efficiency. The core objective of this study is to utilize the acquired water quality parameter data for efficient classification and assessment of water samples, with the aim of streamlining traditional laboratory-based water quality analysis processes. By developing a reliable water quality classification model, this research provides robust technical support for water safety management. [ABSTRACT FROM AUTHOR]

Groundwater quality is a critical concern for human health, particularly in urban areas like the eastern part of Tehran Plain, where geological features and anthropogenic activities contribute to contamination risks. This study aimed to assess the quality of groundwater in this region, focusing on its implications for public health. The objectives of the study were to identify factors influencing hydrogeochemistry, evaluate environmental risk based on metal(loid)s using water quality indices, and conduct a health risk assessment. Groundwater samples were collected and analyzed for chemistry, water quality, heavy metal contamination, and associated health risks. The results indicated a relatively stable pH condition and a wide variation in the concentration of dissolved solids. The Water Quality Index (WQI) was employed to evaluate the overall water quality, revealing that approximately 50% of the samples fell into the poor and very poor quality categories, with two samples deemed unsuitable for drinking. Heavy metal contamination varied across different metals, with some indicating low levels while others showed moderate to very high levels. Priority pollutants such as mercury and arsenic were identified as having a greater potential impact on water quality deterioration. Exposure and health risk assessments indicated a negligible risk associated with aluminum exposure but high risks associated with arsenic, chromium, and mercury exposure. Carcinogenic risk assessments for arsenic, chromium, and mercury exceeded acceptable thresholds, emphasizing the urgent need for further investigation into contamination sources and strategies for mitigation. These findings highlight the importance of continuous monitoring and sustainable groundwater management practices, providing valuable insights for other regions facing similar challenges in groundwater quality and public health. [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]

Persistent exposure to arsenic, chromium, cadmium, lead, and selenium in drinking water above permissible levels poses significant health risks, including increased incidences of skin, lung, bladder, and kidney cancers. This study evaluated 34 water samples from Rupnagar district, Punjab, for heavy metal content. Health risks were assessed using hazard quotient (HQ) and chronic daily intake metrics. Aluminium concentrations were highest in Block Nurpur Bedi (36.43 mg/L). Arsenic levels in Ropar and Anandpur Sahib were 0.09 and 0.068 mg/L, respectively. Cadmium was highest in Nurpur Bedi (0.041 mg/L). Morinda had the highest selenium concentration (0.0038 mg/L). Lead was detected across all blocks, peaking in Chamkaur Sahib (2.176 mg/L). The HQ exceeded unity in nearly all areas, indicating significant health risks from aluminium, arsenic, and lead. The hazard index was highest in Nurpur Bedi (2.66) for adults. Incremental Life Cancer Risk (ILCR) values indicated a high cancer risk from arsenic, chromium, and lead across all blocks. One-way analysis of variance revealed significant differences among Fe, As, and Al concentrations (p < 0.05). The findings underscore the need for targeted treatment technologies and policies to mitigate heavy metal contamination and its health impacts in Punjab. [ABSTRACT FROM AUTHOR]

Concentrations of 222Rn and other toxic metals (Ni, Cu, Fe, Cd, Zn, Pb, Cr, and Mn) were measured by alpha spectrometry using Rad7 and atomic absorption spectrophotometry, respectively, in the water samples from the Ilokun dumpsite, Ado-Ekiti, Nigeria. The physicochemical parameters of the groundwater were also assayed to determine its suitability for drinking and irrigation purposes. While the physicochemical parameters met the World Health Organization (WHO)-safety standards, Cu, Fe, Cd, Pb, Cr, and Mn exceeded permissible limits. Hazard index (HI) values for adults (8.40) and children (39.23) indicated heightened susceptibility to non-carcinogenic health risks among both age group populations. The 222Rn concentrations present in the studied samples range from 5.4 to 23.1 Bq l−1 with an average of 13.9 Bq l−1. Approximately 60% of the samples have radon concentrations above the US Environmental Protection Agency (EPA)-maximum contaminant level of 11.1 Bq l−1. The evaluated radiation doses to the stomach and respiratory tract due to radon content in the water are well below the WHO-specified individual dose criterion of 0.1 mSv year−1. This study suggests a need for groundwater resource management strategies and measures to protect human health from radiological and toxicological risks associated with groundwater consumption around the Ilokun dumpsite. [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]

The amount and thickness of clay layers and surrounding organic elements have a direct impact on how well an aquifer protects itself. Thus, the purpose of this work was to evaluate Orire Estate's ability to preserve the aquifer in Akure, Ondo State, Nigeria, using a geophysical survey that used the Vertical Electrical Sounding (VES) and Very Low Frequency (VLF) Electromagnetic Technique. Throughout the course of the survey, seven traverses of various lengths were established, and VLF-EM measurements were made every five meters along the four main profiles. Thirteen vertical electrical soundings were also performed, with electrode spacings varying from one to one hundred meters. Computer-assisted modeling and partial curve matching approaches were used in the interpretation of the data. Four subsurface geological units were identified by the analysis: topsoil, worn layer, fractured basement, and fresh basement. The topsoil layer, with a thickness ranging from 0.9 to 1.5 meters, exhibited resistivity values between 57.0 and 198.4 Ω-m. The worn layer varied in thickness from 2.6 to 17 meters, with resistivity values from 87.0 to 978.7 Ω-m. The fractured basement layer's thickness ranged from 7.8 to 23.7 meters, showing resistivity values between 311 and 3041.8 Ω-m, while the fresh basement layer demonstrated resistivity values ranging from 1423.1 to 3790.57 Ω-m with infinite thickness. The presence of zones with poor aquifer-protective capacity throughout the study area indicates a heightened vulnerability to contamination from leachates and other pollutants. The subsurface conditions suggest an abundance of unconsolidated sand with limited clay, which prolongs the residence time of percolating pollutants and diminishes the necessary impediment to fluid movement for effective filtration. [ABSTRACT FROM AUTHOR]

Observation results on the south coast of Jember show that there are differences in the characteristics of groundwater in several residents' dug wells, namely some are fresh and brackish. Based on the findings of these problems, the aim of this research is to analyze and map soil quality based on quality standards with geological observations on the south coast of Jember. This research uses quantitative methods through surveys to determine the quality of groundwater used for drinking water in the Jember South Coastal Area with the parameters tested including TDS, odor, taste, pH, sulfate, chloride and hardness. The results of groundwater quality on the southern coast of Jember Regency show that based on the test results of physical parameters and chemical parameters, most of the air samples are of drinking quality. The results of groundwater quality mapping with geological observations based on the Jember geological map sheet show that 47 km2 (17,8%) of non-drinkable areas are located on alluvial plains interspersed with puger formations in the form of limestone which has high porosity and permeability and 227 km2 (82,2%) the potable area is located in geological interbeds of sandstone and clay with low porosity and permeability. [ABSTRACT FROM AUTHOR]

This study examines the impacts of climate change on groundwater quality and recharge in the Tensift Basin, focusing on the Haouz, Bahira, and Essaouira aquifers. Analysis of data collected from 2013 to 2017 reveals significant spatial and temporal variability in water quality, driven by both natural and anthropogenic factors. In the Haouz aquifer, the proportion of water classified as "Excellent" quality dropped from 7% in March 2013 to 0% by July 2017, while "Good" quality water increased from 47% to 60%. The Bahira aquifer consistently showed 45% to 64% of water samples falling under "Average" quality, with occasional increases in "Poor" quality water up to 45%. The Essaouira aquifer exhibited a consistent presence of "Average" quality water at 75%, with "Poor" quality water observed in some instances. These trends indicate a decline in water quality exacerbated by climate change effects such as increased evapotranspiration, altered precipitation patterns, and rising sea levels. The study underscores the urgent need for comprehensive groundwater management strategies, including improved monitoring, sustainable water use practices, and adaptive measures to mitigate the impacts of climate change. These efforts are crucial for ensuring safe drinking water, protecting public health, and sustaining groundwater resources in the region. [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]

The study focuses on assessing groundwater quality, with a special emphasis on fluoride contamination, in the Muktsar, Bathinda, and Moga of Punjab, India. Groundwater being a crucial resource for the region, faces contamination from both natural processes and anthropogenic activities. The study employs advanced techniques, including Geographic Information Systems (GIS) and machine learning models to predict fluoride contamination and assess the water quality index (WQI). The groundwater samples were systematically collected from 281 locations using GIS at approximately 5 km distance to ensure uniform distribution. The study aims to predict fluoride levels, various hydrochemical parameters and WQI to identify high-risk areas. Using Inverse Distance Weighting (IDW), the distribution of fluoride level and WQI was mapped, revealing varying concentrations across the study area. From the study, the Random Forest (RF) model identified key hydrochemical parameters influencing fluoride contamination. The RF model demonstrates high predictive accuracy for fluoride contamination, using the receiver operating characteristic (ROC) curves for validation and yield area under the curve (AUC) values of 82%, 81%, and 94% for Muktsar, Bathinda, and Moga districts, respectively. The novel integration of GIS with machine learning provides a robust framework offering valuable insights for water resource management. The results showed significant fluoride contamination in many areas, posing serious health risks like dental and skeletal fluorosis. The findings highlight the importance of addressing both natural and human-induced factors in managing groundwater quality, ensuring safe drinking water, and protecting public health in affected regions. [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]

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]

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]