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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]

Abstract This study is the first attempt to characterize the quality status of El Fahs aquifer by combining graphical tools, multivariate statistical techniques and traditional geostatistical methods. Water samples are collected from thirty-six observation wells during April 2016 to characterize the physicochemical properties of the aquifer. Subsequently, these samples are partitioned into three hydrochemically distinct water classes (i.e., C1, C2, and C3) using the K-means clustering method. Principal Component Analysis is used to reduce the dimensionality of the dataset prior performing the clustering computations, resulting in clusters of higher quality than the non-reduced case in terms of Silhouette coefficient. Piper diagram is used to display the chemical composition of the samples, revealing the dominant role of Mg–Ca–Cl water type for all three classes, whereas Sodium and Sulfate were found to be the second most important cations and anions respectively. Indicator kriging (IK) is used to identify the probability of occurrence of the hydrochemical classes beyond the sampling locations. It is found that Class 1, associated with fresh groundwater component, is most probable to occur at the central part of the plain, mainly due to the presence of a dense hydrological network, whereas Classes 2 (agricultural activities) and 3 (dissolution of evaporate geological formations) are expected to occur at the southern and northern regions respectively. IK also identified the regions associated with high levels of uncertainty, mostly occurring in a large portion of the northern area due to the absence of available hydrochemical information. The results showed that integration of graphical methods, multivariate statistical techniques and geostatistical modeling, is an efficient approach for characterizing the hydrochemical status of the aquifer system, to spatially optimize the groundwater monitoring well networks and quantify the uncertainty levels of the water classes in a systematic way.

This study is the first attempt to characterize the quality status of El Fahs aquifer by combining graphical tools, multivariate statistical techniques and traditional geostatistical methods. Water samples are collected from thirty-six observation wells during April 2016 to characterize the physicochemical properties of the aquifer. Subsequently, these samples are partitioned into three hydrochemically distinct water classes (i.e., C1, C2, and C3) using the K-means clustering method. Principal Component Analysis is used to reduce the dimensionality of the dataset prior performing the clustering computations, resulting in clusters of higher quality than the non-reduced case in terms of Silhouette coefficient. Piper diagram is used to display the chemical composition of the samples, revealing the dominant role of Mg–Ca–Cl water type for all three classes, whereas Sodium and Sulfate were found to be the second most important cations and anions respectively. Indicator kriging (IK) is used to identify the probability of occurrence of the hydrochemical classes beyond the sampling locations. It is found that Class 1, associated with fresh groundwater component, is most probable to occur at the central part of the plain, mainly due to the presence of a dense hydrological network, whereas Classes 2 (agricultural activities) and 3 (dissolution of evaporate geological formations) are expected to occur at the southern and northern regions respectively. IK also identified the regions associated with high levels of uncertainty, mostly occurring in a large portion of the northern area due to the absence of available hydrochemical information. The results showed that integration of graphical methods, multivariate statistical techniques and geostatistical modeling, is an efficient approach for characterizing the hydrochemical status of the aquifer system, to spatially optimize the groundwater monitoring well networks and quantify the uncertainty levels of the water classes in a systematic way. [ABSTRACT FROM AUTHOR]

In arid and semiarid zones, groundwater is a vital and indispensable natural resource. Indeed, these water resources have become extremely limited due to several factors, including climate change, salinization, and overexploitation. This study covers the hydrochemical characterization of groundwater in the Nekor-Ghiss plain which is located in northern Morocco. To achieve this objective, a set of 79 water samples was analyzed, for various physical and chemical parameters of the samples, including E.C, pH, TDS, HCO3−, SO42−, Ca2+, Mg2+, Na+, K+, PO43−, NO3−, NO2− and NH4+. Several methods were used to interpret the hydrochemical data, namely graphical methods, principal component analysis (PCA), hierarchical ascending classification, and ion exchange indices. A detailed geochemical study of groundwater is described to identify the origin of the chemical composition of groundwater. The results show that the samples studied are characterized by very high mineralization (> 1500 mg/l), with the predominance of Na+, Cl− and SO42− ions. The interpretation of geochemical signatures of groundwater in the Nekor-Ghiss plain shows sulfate-sodium (Na–SO4) and chloride-sodium (Na–Cl) facies. Natural geochemical processes are responsible for water regulation, while human activities exert a limited influence on this control. Marine intrusion, evaporation, and the ion exchange process largely control the chemistry of the aquifer. Using PCA to confirm controlled water chemistry processes revealed three homogeneous groups. The study contributes to a better understanding of the quality and mineralization of groundwater in the Nekor-Ghiss plain, and it will serve as a reference for other plains with similar characteristics. [ABSTRACT FROM AUTHOR]

Assessing groundwater quality is critical to regional water resource conservation and human health safety, especially in areas with co-existence of toxic constituents fluoride (F−) and arsenic (As). In this study, fourteen groundwater samples were collected in Feng County, Northwestern Jiangsu Province to identify dominant contaminants and their spatial distribution and health risk. The composition and variation characteristics of major ions (K+, Na+, Ca2+, Mg2+, Cl−, SO42−, HCO3−, and NO3−) and trace elements (F−, As, and Mn) were analyzed. The hydrochemical results revealed that high F− groundwater was mainly distributed in the northern areas whereas As-riched groundwater was primarily distributed in southern areas. Notably, over 85.7% and 21.4% of the shallow groundwater samples exceeded the drinking water quality standard of 1.5 mg/L for F− and 10 µg/L for As, respectively. Based on the water quality index (WQI) appraisal result, 71.4% of the groundwater in the study area is classified as "poor", and thus unsuitable for drinking directly. We assessed the human non-carcinogenic health risk of F− (HQFluoride) and As (HQArsenic) and the carcinogenic health risk of As (CRArsenic). The calculated hazard quotient (HQ) for F− indicated nearly all groundwater samples have an unacceptable risk (HQ > 1) for each age group. However, HQArsenic values revealed that 28.6%, 21.4%, 21.4%, and 21.4% of groundwater samples posed potential non-carcinogenic health risks for infants, children, females, and males, respectively. The calculated results of CRArsenic showed that 0%, 21.4%, 28.6%, and 28.6% of groundwater samples posed unacceptable health risks (CR > 1.0 × 10−4) to infants, children, females, and males, respectively. The groundwater irrigation suitability assessment results showed that 21.4% of samples were doubtful to unsuitable for irrigation, and 85.7% owed magnesium hazards. The findings of this study will assist policymakers in formulating proper remedial policies and mitigation strategies to ensure the safety of drinking and irrigation water. [ABSTRACT FROM AUTHOR]

Climate change has clearly affected the desert city of Bechar, located in southern Algeria, and this miserable situation for the supply of drinking water prompted the authorities to provide capabilities and funds to bring groundwater located 250 km away and transfer it to the city of Bechar. The characterization of these underground waters presents a bicarbonate-magnesian facies according to the diagram of Schöeller and Berkaloff; the representation of the data on the triangular Piper diagram shows that Boussir ground water has the magnesium bicarbonate facies. The calculation of the quality index (GWQI) shows that all samples taken from the boreholes belong to the good quality category. The long distance of diversion of this underground water and the quality of the materials used in the project under a dry desert climate made us carry out the process of monitoring and tracking the quality of the water from the well until it reaches the consumer. The results revealed that all the levels of the physic-chemical parameters do not exceed the WHO portability standards, except that a variation of certain values was observed at the level of the storage tank, this variation due to the mode of filling and the mixing of water in tubular form, without eliminating the effect of water stagnation. If we technically know how to produce high-quality drinking water, we cannot always ensure a safe and sustainable water supply of the same quality in distribution networks and reservoirs; it is from this principle that our article is based in order to reinforce the monitoring role. [ABSTRACT FROM AUTHOR]

Abstract Assessing groundwater quality is critical to regional water resource conservation and human health safety, especially in areas with co-existence of toxic constituents fluoride (F−) and arsenic (As). In this study, fourteen groundwater samples were collected in Feng County, Northwestern Jiangsu Province to identify dominant contaminants and their spatial distribution and health risk. The composition and variation characteristics of major ions (K+, Na+, Ca2+, Mg2+, Cl−, SO4 2−, HCO3 −, and NO3 −) and trace elements (F−, As, and Mn) were analyzed. The hydrochemical results revealed that high F− groundwater was mainly distributed in the northern areas whereas As-riched groundwater was primarily distributed in southern areas. Notably, over 85.7% and 21.4% of the shallow groundwater samples exceeded the drinking water quality standard of 1.5 mg/L for F− and 10 µg/L for As, respectively. Based on the water quality index (WQI) appraisal result, 71.4% of the groundwater in the study area is classified as “poor”, and thus unsuitable for drinking directly. We assessed the human non-carcinogenic health risk of F− (HQFluoride) and As (HQArsenic) and the carcinogenic health risk of As (CRArsenic). The calculated hazard quotient (HQ) for F− indicated nearly all groundwater samples have an unacceptable risk (HQ > 1) for each age group. However, HQArsenic values revealed that 28.6%, 21.4%, 21.4%, and 21.4% of groundwater samples posed potential non-carcinogenic health risks for infants, children, females, and males, respectively. The calculated results of CRArsenic showed that 0%, 21.4%, 28.6%, and 28.6% of groundwater samples posed unacceptable health risks (CR > 1.0 × 10−4) to infants, children, females, and males, respectively. The groundwater irrigation suitability assessment results showed that 21.4% of samples were doubtful to unsuitable for irrigation, and 85.7% owed magnesium hazards. The findings of this study will assist policymakers in formulating proper remedial policies and mitigation strategies to ensure the safety of drinking and irrigation water.

The groundwater quality of the Gopalganj district in Bangladesh was not well documented. Therefore, this research was done to determine the groundwater quality in the study area. The water quality index and the human health risk for heavy metal ingestion were used to describe the water quality. The water quality was performed through the estimation of turbidity, pH, electrical conductivity, total dissolved solids, and concentration of sodium, potassium, ammonium, nitrate, iron, manganese, zinc, copper, and arsenic. The mean turbidity, pH, and total dissolved solids in the two upazila were within the permissible limit. However, the electrical conductivity in both the upazila was higher than the WHO-prescribed value in which the higher concentration was in Kotalipara. Excess concentrations of iron and arsenic were found in the Kashiani upazila, but these were below the detection limit in Kotalipara upazila. The water quality index revealed that roughly 61.0% of samples of Kashiani upazila were of poor quality. However, about 96.0% of samples of Kotalipara upazila were of excellent quality. Chronic health risks due to the revelation of drinking have also been determined by assessing the hazard quotient and hazard index. In Kashiani, almost 85.0% of samples were elevated chronic risks for adults and 100.0% of the samples were very high chronic risks for children. In Kotalipara, all the samples (almost 100%) were suggested to have a lower chronic risk for adults and children. The results suggested that the carcinogenic risk of arsenic via oral exposure was very high for both adults and children in Kashiani upazila. [ABSTRACT FROM AUTHOR]

Water quality is one of the most relevant issues related to water management, with water pollution and access to clean water for drinking and irrigation being common issues in developing countries. Groundwater is an available water source, especially where surface sources are scarce or unsuitable. In this sense, studies to improve knowledge of aquifers should be undertaken where information on groundwater resources is not available. In the current study, 50 groundwater samples were collected from rural and urban wells used by local communities for human consumption and to irrigate local crops. Several indices for drinking water and irrigation use have been used for the assessment of water quality. Conversely, the carcinogenic and noncarcinogenic human health risks due to exposure to heavy metals in the groundwater were estimated, as were the predominant hydrochemical characteristics. The groundwater water quality index (GWQI) shows values < 100 for all the samples; groundwater is recommended for drinking after disinfection. By contrast, the irrigation water quality index (IWQI) shows that 80% of groundwater samples pose a potential threat to irrigation, with restriction categories ranging from high to severe. The individual hazard quotients were < 1. However, the multielement and multipathway hazard index (HI) for children and adults were > 1, whereas As and Mn had a higher contribution to the HI. The Piper trilinear diagram shows that hydrochemical facies of Ca2+ and HCO3− are significantly dominant. By contrast, weathering of rocks and atmospheric precipitation is the dominant factors regulating the chemistry of groundwater in the aquifer system of La Mojana. Our findings indicate that there are significant potential noncarcinogenic health risks for local populations exposed to groundwater. [ABSTRACT FROM AUTHOR]

The Sundarban region—located from the Hooghly River in India's state of West Bengal to the Baleswar River in Bangladesh—renowned for its distinctive ecosystem and agricultural techniques, heavily depends on groundwater for irrigation purposes. However, concerns arise regarding the suitability of groundwater for sustainable agriculture in this vulnerable coastal zone. This systematic review aims to comprehensively evaluate the quality and appropriateness of groundwater and surface water for irrigation in the Sundarban region. By extensively searching scientific databases and relevant literature, we identified eighteen studies meeting our inclusion criteria. These studies encompassed hydrological, hydrochemical, and agronomic parameters, facilitating a thorough assessment of groundwater quality and its potential impacts on crop productivity. The review evaluates key parameters such as total hardness, residual sodium carbonate, potential salinity, permeability index, Kelly's ratio, sodium absorption ratio, corrosivity ratio, and chloroalkaline indices. The results revealed that irrigation water displays an alkaline nature, and both surface water and groundwater were unsuitable for irrigation due to exceedingly high-quality parameters beyond the standard limits. Nevertheless, groundwater exhibited favorable physiochemical properties. The review identifies critical research gaps and proposes future directions to enhance the understanding of groundwater suitability for irrigation in the Sundarban region. The findings emphasize the necessity of a multidisciplinary approach to ensure sustainable agricultural practices and safeguard the delicate ecosystem of the Sundarban region. [ABSTRACT FROM AUTHOR]

Abstract Groundwater quality assessment is crucial for the sustainable management of water resources in arid regions, where groundwater is the primary source of water supply and increasing demand raises concerns. The study area in Southwest Algeria relies heavily on groundwater as a source of water supply, and the increasing demand for freshwater raises concerns about the quality of groundwater. To assess the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region, multivariate statistical methods, geochemical modeling and water quality indices were employed. The study revealed that the groundwater samples could be classified into four water groups using hierarchical cluster analysis Q mode (HCA), namely Ca–Mg–HCO3, Ca–Mg–Cl–SO4, Ca–SO4 and Na–Cl. Factor analysis was used to identify the main factors controlling the study area’s hydrochemical processes. The results indicated that water–rock interaction, reverse ion exchange and anthropogenic pollution were the main hydrochemical processes affecting groundwater chemistry. The water quality index indicated that the groundwater was suitable for human consumption, with only 2.32% of the samples being unsuitable. Additionally, the groundwater was suitable for agricultural use, but salinity control was necessary. The saturation index values showed that the groundwater was supersaturated with aragonite, calcite, dolomite, anhydrite and gypsum, and undersaturated with halite. Ca-smectite, Mg-smectite and kaolinite were identified as the primary processes controlling the chemical composition of groundwater. The application of multivariate statistical methods, geochemical modeling and water quality indices provided a comprehensive understanding of the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region. The findings of the study can serve as a useful basis for future studies on groundwater quality assessment in the region.

Groundwater quality assessment is crucial for the sustainable management of water resources in arid regions, where groundwater is the primary source of water supply and increasing demand raises concerns. The study area in Southwest Algeria relies heavily on groundwater as a source of water supply, and the increasing demand for freshwater raises concerns about the quality of groundwater. To assess the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region, multivariate statistical methods, geochemical modeling and water quality indices were employed. The study revealed that the groundwater samples could be classified into four water groups using hierarchical cluster analysis Q mode (HCA), namely Ca–Mg–HCO3, Ca–Mg–Cl–SO4, Ca–SO4 and Na–Cl. Factor analysis was used to identify the main factors controlling the study area's hydrochemical processes. The results indicated that water–rock interaction, reverse ion exchange and anthropogenic pollution were the main hydrochemical processes affecting groundwater chemistry. The water quality index indicated that the groundwater was suitable for human consumption, with only 2.32% of the samples being unsuitable. Additionally, the groundwater was suitable for agricultural use, but salinity control was necessary. The saturation index values showed that the groundwater was supersaturated with aragonite, calcite, dolomite, anhydrite and gypsum, and undersaturated with halite. Ca-smectite, Mg-smectite and kaolinite were identified as the primary processes controlling the chemical composition of groundwater. The application of multivariate statistical methods, geochemical modeling and water quality indices provided a comprehensive understanding of the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region. The findings of the study can serve as a useful basis for future studies on groundwater quality assessment in the region. [ABSTRACT FROM AUTHOR]

Identifying and predicting the nitrate inflow and distribution characteristics of groundwater is critical for groundwater contamination control and management in rural mixed-land-use areas. Several groundwater nitrate prediction models have been developed; in particular, a nitrate concentration model that uses dissolved ions in groundwater as an input variable can produce accurate results. However, obtaining sufficient chemical data from a target area remains challenging. We tested whether machine learning models can effectively determine nitrate contamination using field-measured data (pH, electrical conductivity, water temperature, dissolved oxygen, and redox potential) and existing geographic information system (GIS) data (lithology, land cover, and hydrogeological properties) from the Nonsan Stream Watershed in South Korea, an area where nitrate contamination occurs owing to intensive agricultural activities. In total, 183 groundwater samples from different wells, mixed municipal sites, and agricultural activities were used. The results indicated that among the four machine learning models (artificial neural network (ANN), classification and regression tree (CART), random forest (RF), and support vector machine (SVM)), the RF (R2: 0.74; RMSE: 3.5) and SVM (R2: 0.80; RMSE: 2.8) achieved the highest prediction accuracy and smallest error in all groundwater parameter estimates. Land cover, aquifer type, and soil drainage were the primary RF and SVM model input variables, representing agricultural activity-related and hydrogeological infiltration effects. Our research found that in rural areas with limited hydro-chemical data, RF and SVM models could be used to identify areas at high risk of nitrate contamination using spatial variability, GIS-aided visualization, and easily accessible field-measured groundwater quality data. [ABSTRACT FROM AUTHOR]

The impacts of climate change-induced warming on our ecosystems can no longer be neglected, but our understanding of consequences for groundwater ecosystems in general and groundwater quality in particular is alarmingly incomplete. In this review, we therefore provide an overview of the current state of knowledge related to the impact of global warming on our precious groundwater resources. Groundwater warming in shallow aquifers is closely associated with increasing average land surface temperatures and has already reached + 1 K compared to pe-industrial times. Until the end of the twenty-first century, temperature increases in local groundwater of up to + 10 K are possible. Monitoring data, laboratory and field experiments all provide evidence that such temperature increases are sufficient to substantially modify groundwater quality through numerous and interlinked biogeochemical processes, which we have summarized in a conceptual overview. Warming impacts on groundwater are highly site-specific and spatially heterogeneous, which complicates their assessment and prediction. Locally, shallow unconfined and nutrient-rich floodplain aquifers are most susceptible to warming-induced changes. Importantly, processes affecting water quality are not only modified by a long-term rise in groundwater temperatures, but also in the short-term during weather extremes, which is of great relevance for riverbank filtration. At the regional scale, aquifers in cold regions impacted by permafrost thawing are especially vulnerable to warming. As the majority of temperature-sensitive processes affecting groundwater quality are not or only very slowly reversable, we pressingly require comprehensive mechanistic understanding before it is too late to develop suitable countermeasures and management strategies. [ABSTRACT FROM AUTHOR]

Abstract Salah Al-Din Provence is an active agriculture and population region. One of its primary water sources is groundwater, which suffers from a lack of information regarding water quality and hydrochemistry. In order to study those missing variables, 27 samples from wells of shallow tubes were collected for analyzing the relevant physicochemical indices that help to produce the Schoeller index, Piper diagram, and Gibbs plot. Piper diagram revealed a hydrochemistry behavior of different values along with the groundwater samples. The chemistry of wells was controlled primarily by the evaporation process according to the Gibbs plot. The values of the Schoeller index of the studied samples stated that 59% of them have disequilibrium in Chloro-Alkaline due to their negative obtained values while the rest of them produced positive estimates, which indicates an exchange reaction of cation–anion basic domination. It was concluded that carbonate and silicate weathering, as well as evaporation, controlled the region’ s hydrochemistry. Using Water Quality Index, groundwater was evaluated for use as drinking water. While using Sodium Adsorption Ratio, Sodium percentage, Residual Sodium Carbonate, Magnesium Hazard, and US salinity diagram were all used for estimating the same water’ s suitability for irrigation. All of those indicators, as well as the Gibbs ratio, show that all 27 samples were unsuitable for both studied usage. In addition, those results indicate that evaporation is a major problem for groundwater in this area. Finally, using cluster analysis it was concluded that there are two types of similarities that indicate different levels of pollution in groundwater.

The physico-chemical parameters and WQI of ground water in all five blocks of district Nuapada are calculated by taking ten samples from each block in the month of October 2019. The correlation study between different physicochemical parameters shows significant negative relationships. The WQI of ground water on Boden block is 472.1, Kharial is 366.7, Sinapali block is 319.82, Komana block is 344.1, and Nuapada block is 225.65. Hence the ground water of all these blocks is E-class and not fit for human use. Among all these blocks, the Boden block is highly polluted. The mean value of fluoride in the Boden block is 6.17 mg/l, the Kharial block is 4.79 mg/l, the Sinapali block is 3.93 mg/l, the Komana block is 4.47 mg/l, and the Nuapada block is 2.86 mg/l. Hence, the present study reveals that the groundwater quality of different regions of the district Nuapada is heavily polluted and not suitable for drinking. [ABSTRACT FROM AUTHOR]

A groundwater quality map serves as a deterrent mechanism that provides insight into likely environmental health predicaments. The objective of this study was to create map and evaluate the quality and changes in groundwater during the study period in Erbil, Iraq. Based on the 13 groundwater parameters, the water quality index (WQI) was calculated for 61 wells from 2015 to 2017 for wet and dry seasons. To generate WQI maps, two geostatistical analyst tools in Geographical Information Systems, including Kriging and Inverse Distance Weighted (IDW) were used. For determining the most suitable method, statistical indices were applied to the obtained data. The results showed that the Kriging method increases the prediction accuracy compared to the IDW method. The water quality in 2017 was decreased compared to the previous years and the WQI was increased from 1.64% to 11.47%. Untreated domestic and industrial wastewater causes groundwater pollution which was the main reason for the decrease in the water quality of Erbil city. [ABSTRACT FROM AUTHOR]

Salah Al-Din Provence is an active agriculture and population region. One of its primary water sources is groundwater, which suffers from a lack of information regarding water quality and hydrochemistry. In order to study those missing variables, 27 samples from wells of shallow tubes were collected for analyzing the relevant physicochemical indices that help to produce the Schoeller index, Piper diagram, and Gibbs plot. Piper diagram revealed a hydrochemistry behavior of different values along with the groundwater samples. The chemistry of wells was controlled primarily by the evaporation process according to the Gibbs plot. The values of the Schoeller index of the studied samples stated that 59% of them have disequilibrium in Chloro-Alkaline due to their negative obtained values while the rest of them produced positive estimates, which indicates an exchange reaction of cation–anion basic domination. It was concluded that carbonate and silicate weathering, as well as evaporation, controlled the region' s hydrochemistry. Using Water Quality Index, groundwater was evaluated for use as drinking water. While using Sodium Adsorption Ratio, Sodium percentage, Residual Sodium Carbonate, Magnesium Hazard, and US salinity diagram were all used for estimating the same water' s suitability for irrigation. All of those indicators, as well as the Gibbs ratio, show that all 27 samples were unsuitable for both studied usage. In addition, those results indicate that evaporation is a major problem for groundwater in this area. Finally, using cluster analysis it was concluded that there are two types of similarities that indicate different levels of pollution in groundwater. [ABSTRACT FROM AUTHOR]

The extensive exploitation of water resources in Chaharmahal va Bakhtiari province has led to a destructive impact on the water balance and quality of the region. In order to evaluate water quality of the study area, water quality parameters from 132 wells were analyzed to prepare spatial distribution maps of the IRWQI index. To analyze spatial and temporal rainfall anomalies, the SPI index was spatially interpolated using the ordinary Kriging method. Principal component analysis was used to investigate the relationship between water quality parameters. The suitability of data for PCA was evaluated by the Kaiser–Meyer–Olkin and Bartlett tests. Additionally, water balance components of the study area, including surface runoff and ground water, were simulated using the WetSpass-M model. According to the results of the IRWQI index, 54 wells, mostly located in built-up and agricultural lands, had poor quality․ Investigation of the average groundwater quality during the years 2007 to 2017 shows that the trend of groundwater quality decreased. Comparison of drought and water quality maps showed similar patterns so that in areas with extreme drought, water quality was bad. The highest and lowest recorded concentrations for nitrates were related to built-up and rangeland lands with concentrations of 35 and 21 mg/l, respectively. Comparison among land use classes showed that in the rangelands, groundwater quality was better and nitrate level was lower compared to agricultural and built-up areas. Overall, the results of this study show that water quality can be affected by land use types and water balance components. [ABSTRACT FROM AUTHOR]

The Nubian sandstone aquifer (NSA) is defined by using 19 vertical electrical sounding (VES) stations, 201 gravity stations, which define the structures that control the configuration of the NSA, and 183 land magnetic stations, which define the lower surface of the NSA by determining the depth of the basement surface. In order to assess the top of the NSA, we collected and analyzed 19 deep VESes. The upper surface depth of the NSA spans from 707 to 1154 m, according to the interpretation results for various geophysical data. Additionally, the aquifer's resistivities ranged from 30.2 to 477 Ω m, which indicates good groundwater quality. According to the interpretation of the gravity result, the study region is influenced by many structural characteristics of different trends, including northwest–southeast, northeast–southwest, and east–west trends. The upper surface depth of crystalline rocks (also known as basement rocks) is determined by three-dimensional magnetic modeling to range between 967 and 4122 m. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the suitability of groundwater for domestic and agricultural use in the Rafsanjan plain, southwest part of the Daranjir–Saghand basin, Iran. Fifty-five groundwater samples were collected and analyzed by six methods including the water quality index (WQI), Schoeller diagram, irrigation water quality (IWQ) parameters, Piper diagram, US salinity diagram and Wilcox diagram. The spatial distribution maps of chemical parameters and groundwater quality indices were plotted using the IDW method in GIS. The results showed a low concentration of major ions in the southeastern part and a high concentration from the central part towards northwestern part of the plain. The concentration of major ions in groundwater was strongly affected by groundwater flow, geological setting and the existence of the evaporative layers in the studied area. Moreover, results revealed that most of samples exceeded the acceptable limits recommended by the WHO and ISIRI1053 standards for domestic and agricultural purposes. In most of the wells, groundwater was classified into saline and very hard categories. The analyses based on WQI values indicated that above 87% of water samples were unsuitable for drinking purposes. IWQ parameters expressed that 85%, 67%, 32%, 51%, 43% and 50% of samples had EC > 3000, Na% > 60%, MAR > 50%, KR > 1, SAR > 9 and Cl− > 350, respectively, which were unsuitable for irrigation use. The dominant hydrochemical facies of water was Na–Cl–SO4 type, and 63% and 22.8% of samples were categorized as C4S4 and C4S3 class, with very high-salinity–high-sodium hazards and very high-salinity–high-sodium hazards, respectively. It indicated that most irrigated lands in this study area were affected by different levels of salinity and sodicity hazards that caused decreases in plant growth and crop productivity. The results can assist decision-makers and planners in prioritizing groundwater resources management in the region.

Abstract Groundwater (GW) is an important source of freshwater in arid and semiarid areas. Some important industrial activities, such as coal mining, also consume GW. There have been few studies evaluating GW quality in the Selian coal mining area of Inner Mongolia. This study aimed to identify the hydrochemical phases and the sources of main ions in the GW of the Selian coal mining area. Water quality analysis was performed on 20 shallow GW samples collected from the study area. Statistical correlation analysis was performed on these water quality data. The quality of irrigation water was evaluated based on water quality indices such as the sodium absorption rate and sodium percentage. The risk of nitrate pollution in the study area to human health was evaluated by GW nitrate content. The results show that the dominant GW chemistry types in the study area are the mixed and Ca–HCO3 types. Correlation analysis indicates that rock weathering and leaching are the main natural drivers of GW hydrochemistry in this area. The irrigation risk analysis shows that GW in this area can be used for irrigation, although some caution is needed. The human health risk assessment shows that GW nitrate pollution poses more risk to children than to adults by a factor of 1.168. It is recommended that centralized treatment of drinking water is the optimal approach to managing this risk. The results of this study can act as a reference for the rational use of GW and for control of nitrate pollution in this area.

Management and protection of regional water resources requires an understanding of the hydrological characteristics and water quality changes. In this study, we combined isotopic, geochemical and hydrometric measurements to investigate hydrological characteristics and water quality changes during the interactions between surface water and groundwater in mountain river valley. Our results showed that the stable isotope values in most of the groundwater and river water samples were located above the middle of the local meteoric water line in a mountain river valley. The hydrochemical types of most of the groundwater and river water samples were Ca–Mg–HCO3 and were primarily dominated by rock weathering. The hydrochemical compositions of groundwater and river water were mainly affected by carbonate dissolution and cation exchange, but influences of saltwater intrusion and human activity were found at the lakeside. Precipitation was the main factor affecting the changes in hydrological processes at these groundwater and river water sites and they were also affected by meltwater, soil water and the interaction between groundwater and surface water. The water level of the river increased, and the recharge of the groundwater by river water increased in river valley during the rainy season, which led to an increase runoff path in groundwater. The interaction between the river water and groundwater was affected by the rainfall frequency and intensity, the recharge time of the soil water and the pressure of the river on both sides of the river channels. Additionally, our results indicated that the flow of groundwater into the river will lead to water quality deterioration. The increasing pressure of the river on the groundwater will cause the deterioration of groundwater quality, which will also be affected by saltwater intrusion and human activity. Our results detailed the hydrological characteristics, water quality changes and main influencing factors of the interaction between surface water and groundwater of river valley in mountain, which will be beneficial to promote the reasonable protection of water resources under climate change in the future. [ABSTRACT FROM AUTHOR]

This paper investigates the suitability of groundwater for domestic and agricultural use in the Rafsanjan plain, southwest part of the Daranjir–Saghand basin, Iran. Fifty-five groundwater samples were collected and analyzed by six methods including the water quality index (WQI), Schoeller diagram, irrigation water quality (IWQ) parameters, Piper diagram, US salinity diagram and Wilcox diagram. The spatial distribution maps of chemical parameters and groundwater quality indices were plotted using the IDW method in GIS. The results showed a low concentration of major ions in the southeastern part and a high concentration from the central part towards northwestern part of the plain. The concentration of major ions in groundwater was strongly affected by groundwater flow, geological setting and the existence of the evaporative layers in the studied area. Moreover, results revealed that most of samples exceeded the acceptable limits recommended by the WHO and ISIRI1053 standards for domestic and agricultural purposes. In most of the wells, groundwater was classified into saline and very hard categories. The analyses based on WQI values indicated that above 87% of water samples were unsuitable for drinking purposes. IWQ parameters expressed that 85%, 67%, 32%, 51%, 43% and 50% of samples had EC > 3000, Na% > 60%, MAR > 50%, KR > 1, SAR > 9 and Cl− > 350, respectively, which were unsuitable for irrigation use. The dominant hydrochemical facies of water was Na–Cl–SO4 type, and 63% and 22.8% of samples were categorized as C4S4 and C4S3 class, with very high-salinity–high-sodium hazards and very high-salinity–high-sodium hazards, respectively. It indicated that most irrigated lands in this study area were affected by different levels of salinity and sodicity hazards that caused decreases in plant growth and crop productivity. The results can assist decision-makers and planners in prioritizing groundwater resources management in the region. [ABSTRACT FROM AUTHOR]

The present study focused on evaluating the groundwater hydrogeochemical of shallow aquifers in the semi-arid areas of northern Ethiopia, using geospatial modelling and multivariate statistical techniques. Physico-chemical parameters, including pH, major ions, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), pollution index (PI) and other parameters, from 22 samples have been used to assess water quality, sources of various ions, water types and factors controlling groundwater chemistry. Results showed that the spatial distribution of major ions, EC, TDS, TH and PI values in these samples significantly differ from one location to another due to geological variations and anthropogenic activities of the area. The quality of most groundwater is generally unfit for drinking due to their PI, EC, TH, calcium, potassium, total iron and bicarbonate (HCO3−) values that found to be above the permissible limits of WHO and Ethiopian standards. The parameters like sodium percentage, sodium adsorption ratio (SAR), residual sodium bicarbonate, permeability index, magnesium hazard and Kelly's ratio revealed good quality of groundwater for irrigation utilization, whereas EC of irrigation water (ECiw), combined effects of ECiw − SAR and bicarbonate hazard values indicated that majority of groundwater are not suitable for irrigation use. Piper trilinear diagram classified majority of samples under temporary hardness with Ca–Mg–HCO3 type. Further, Gibbs diagram reveals that water–rock interaction is the major hydrogeochemical processes governing the water chemistry of the study area. Therefore, it is recommended to perform a constant water quality checking program and improvement of tangible management practices for sustainable utilization of groundwater resources. [ABSTRACT FROM AUTHOR]

Longitudinal dispersivity is a crucial parameter for the numerical simulation of groundwater quality, which is highly variable. The use of empirical equations and the inverse solution are two main methods of estimating longitudinal dispersivity. This study investigates the estimation of value and aquifer-wide spatial distribution of longitudinal dispersivity parameters using a combination of the empirical equation, the inverse solution method, and the aquifer zoning technique. The combined approach is applied to Bandar-e-Gaz aquifer in northern Iran, and Willmott's index of agreement was used to assess the simulation precision of total dissolved solids in this aquifer. The values of this criterion were 0.9985–0.9999 and 0.9756–0.9992 in calibration and validation periods showing the developed combined approach obtained high precision for both calibration and validation periods, and the simulation shows remarkable consistency. Also, the one-way sensitivity analysis indicates that the longitudinal dispersivity is more sensitive than the effective porosity in this simulation. The investigation of the spatial distribution of the estimated longitudinal dispersivity by the combined approach indicates that the value of the parameter has a decreasing trend from the south to the north (50–8 m) in the aquifer environment, which is consistent with the changes in the characteristics of porous media in this study area. Therefore, it concludes that the combined approach provides a reliable and appropriate estimation of the spatial distribution of longitudinal dispersivity. [ABSTRACT FROM AUTHOR]

Groundwater is one of the most important natural resources in the world and is widely used for irrigation purposes. Groundwater quality is affected by various natural heterogeneities and anthropogenic activities. Consequently, monitoring groundwater quality and assessing its suitability are crucial for sustainable agricultural irrigation. In this study, the suitability of groundwater for irrigation was determined by using sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Kelly index (KI), percentage of sodium (Na%), magnesium ratio (MR), potential salinity (PS) and permeability index (PI). The groundwater samples were collected and analyzed from 37 different sampling stations for this purpose. Along with suitability analysis, artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) models were used to predict irrigation water quality parameters. The models were evaluated by comparing the measured values and the predicted values using the statistical criteria [coefficient of determination (R2), mean absolute error (MAE), root mean square error (RMSE) and Nash–Sutcliffe efficiency (NS)]. In the estimation of all irrigation water quality parameters, the ANN model has performed much higher compared with the ANFIS model. Spatial distribution maps were generated for measured and ANN model-estimated irrigation water quality indices using the IDW interpolation method. Spatial distributions of groundwater quality indices revealed that MR was higher than the allowable limits in most of the study areas and the other quality criteria were within the permissible limits. It has been determined that the interpolation maps obtained as a result of artificial intelligence methods have appropriate sensitivity when compared with the observed maps. Based on the present findings, ANN models could be used as an efficient tool for estimating groundwater quality indices in unsampled sections of the study area and the other regions with similar conditions. [ABSTRACT FROM AUTHOR]

Abstract Fluoride contamination in groundwater is known from different villages of Talupula Mandal. In the present study in part of SoI toposheet no.57 J/8) of Ananthapuramu district, Andhra Pradesh, the magnitude and credible geogenic sources of the fluoride contamination in groundwater are studied. The present study carried out includes 30 groundwater samples covering an area of 442.89 sq km using (GIS) and (CCME-WQI) techniques. Problem is causally related to fluoride intoxication of human beings and animals through drinking waters. Well waters in the Talupula Mandal surrounded areas carry a high level of fluoride concentrations, much above the internationally decided safety limits. ‘Fluorosis’ is imminent as a result of prolonged intake of waters with more than 1 to 1.5 ppm of fluoride. Fluoride testing results of groundwater from borewell pump using fluoride test kit reveal that about 50% groundwater samples show fluoride concentration more than 4.0 mg/l, 30% samples show between 2.0 and 3.0 mg/l and 20% samples show fluoride concentration is 1–2 mg/l and above (BIS permissible limit: 1.5 mg/l). Agriculture indices are as follows: sodium percentage (Na%) was found between ranges (20.04–55.26), sodium absorption ratio varies from 0.86 to 3.91), Kelly's ratio (KR) varies from 0.22 to 1.16, residual sodium carbonate varies from − 4.12 to 20.66), permeability index (PI) varies from 39.00 to 82.28, magnesium hazard varies from 52.83 to 85.47, potential salinity varies from (0.71–3.15); results shown that the majority of the groundwater samples were suitable for irrigation uses. According to Gibbs’ ratio samples Gibbs ratio 1 (0.04–0.45) and Gibbs ratio 2 (0.44–0.81) fall in the rock dominance. Major ion compositions plotted on a Piper tri-linear diagram indicate that the water is of Ca-HCO3 type and is mixed Ca–Mg–Cl type. The present study indicates that the groundwater chemistry is mostly controlled by geogenic processes (weathering, dissolution and ion exchange) and some extent of anthropogenic activities.

Abstract The objective of the present study was to evaluate the geochemical processes controlling the groundwater chemistry and also to assess the groundwater quality suitability criteria for irrigation purposes. An agricultural region of Telangana, South India, was selected for the present study. A total of 100 groundwater samples were collected and estimated for pH, electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate ( $${\text{HCO}}_{3}^{ - }$$ HCO 3 - ), chloride (Cl−), sulfate ( $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - ), nitrate ( $${\text{NO}}_{3}^{ - }$$ NO 3 - ), and fluoride (F−). The groundwater was characterized by mostly alkaline conditions with a dominance of Na+ and $${\text{HCO}}_{3}^{ - }$$ HCO 3 - ions, indicating the prevailing conditions of weathering and dissolution of silicate minerals. The various geochemical signatures such as Na+ vs Cl−, Ca2+ + Mg2+ vs $${\text{HCO}}_{3}^{ - }$$ HCO 3 - , Ca2+ + Mg2+ vs $${\text{HCO}}_{3}^{ - }$$ HCO 3 - + $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - , $${\text{HCO}}_{3}^{ - }$$ HCO 3 - vs Cl− + $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - , Ca2+ + Mg2+ vs total cations, and Ca2+ + Mg2+ vs Na+ + K+ and the saturation indices with respect to calcite, halite, and gypsum suggest obviously the dominant conditions of carbonate weathering associated with the reverse ion exchange and evaporation processes as the geogenic factors. The linear trend of TDS vs $${\text{NO}}_{3}^{ - }$$ NO 3 - + Cl−/ $${\text{HCO}}_{3}^{ - }$$ HCO 3 - clearly specifies the influence of non-geogenic sources on the aquifer system. These are the important contributors to the variation in the groundwater chemistry. However, the impact of the geogenic source is masking the influence of the anthropogenic source in some areas of the present study region. According to the salinity vs sodium adsorption ratio, residual sodium carbonate, magnesium ratio, and Kelly ratio, 99.9%, 7.06%, 63.07%, and 51.27% of the total study region come under the unsuitable categories for irrigation purposes, respectively. Therefore, the findings of this study recommended some site-specific appropriate management strategies for the safe supply of groundwater for proper crop growth and consequently for sustainable development of the rural environment.

Abstract Groundwater withdrawal at very fast rate poses threat on existing groundwater resources in different parts of the world. This reduction in groundwater levels significantly disturbed the natural aquifer flow rate and thereby different hydrogeochemical processes, which may further impair the groundwater quality. The groundwater quality in rural area of Chhattisgarh State is degraded, and the problem of saline water poses health risk to people. In this research investigation, suitability of groundwater of Bemetara District, Chhattisgarh, India, has been evaluated for drinking purpose through water quality index (WQI) method and principal component analysis (PCA). Total 116 groundwater samples were collected during the pre-monsoon (June 2019) and post-monsoon season (December 2019) and analyzed for physicochemical parameters. Total dissolved solids ranged from 250 to 10,440 mg/L and 289 to 3583 mg/L during pre-monsoon and post-monsoon, respectively, and 55% of the total samples exceeded acceptable BIS limit in pre-monsoon, while about 66% samples exceeded in post-monsoon season. SO4 2− concentrations varied from 3 to 5734 mg/L during pre-monsoon and 4.5 to 2002 mg/L during post-monsoon, respectively. Total 28% samples in pre-monsoon and 18% samples in post-monsoon season exceeded the maximum permissible BIS limit (400 mg/L) of SO4 2− ion in the study area. On the basis of WQI, the quality of groundwater varies from “Excellent water” to “Good water” category. The groundwater of northeastern part of the district is not suitable for drinking, and therefore, it is recommended to treat this groundwater before human consumption with special reference to SO4 2− contamination. PCA inferred that four components are sufficient to explain the variance in chemistry of groundwater that is mainly governed by dissolution of gypsum mineral, other rock–water interaction and anthropogenic activities. Further, water quality was improved in the direction of groundwater flow in the study area, establishing a direct relationship between groundwater flow and water quality of the Bemetara District. This study provides very useful database to design sustainable groundwater management plan for the district.

Abstract Monitoring groundwater quality and analyzing geochemical processes are very crucial in dry environments, especially in areas with intense agriculture and inadequate irrigation management systems. A total of forty-one groundwater samples were collected from the study area and analyzed for major ions chemistry. The results of the geochemical analyses are used to investigate the geochemical processes and make groundwater assessments. The hydrogeochemical characteristics of the groundwater samples revealed a highly mineralized Na+–Cl− water type, implying that the majority of the samples are chemically unfit for human consumption. Based on the water quality parameters analyzed for the groundwater samples collected in this study, such as sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), magnesium hazard (MH), permeability index (PI), and Kelley's ratio (KR), the suitability of groundwater samples for irrigation purposes is good to moderately good. Also they may reflect some alkaline hazard threats to the soil as indicated by the SSP and KR. The salinity hazard is recognized as high and expected to increase with the expansion of irrigation; hence, special salinity control management for groundwater in the study area is required. Nitrate is widely recognized as a contaminant in the study area. The nitrate concentrations range from 0.1 to 256.8 mg/L, with more than 30% of the samples exceeding the safe drinking water limit of 50 mg/L. The main concern is that the average nitrate concentration will likely continue to increase in the groundwater of the study area. Groundwater monitoring, in terms of both quality and quantity, is essential for sustainable groundwater management.

Abstract The groundwater in the Timahdite–Almis Guigou area flows through fluvio-lacustrine and volcanic formations of Plio-Quaternary age and Liassic limestone. The groundwater resources in this area are used for drinking water and irrigation of agricultural plots. 18 groundwater samples were collected for this study. The physico-chemical and bacteriological parameters analysed, such as temperature, electrical conductivity, pH, dissolved oxygen, Na+, K+, Ca2+, Mg2+, Cl−, HCO3 −, SO4 2−, NO2 −, NO3 −, faecal Coliforms, total Coliforms and faecal Streptococci, are used to characterise the quality of the groundwater and its suitability for drinking and for irrigation. The Piper and Gibbs diagrams and the saturation index were used to study the hydrogeochemical characteristics of groundwater. The quality of these was assessed on the basis of bacteriological quantification and water quality index (WQI) for drinking, and calculation of sodium percentage (Na%), sodium adsorption ratio (SAR) and permeability index (PI) for irrigation. The mineral saturation index in groundwater indicates that only carbonate minerals tend to precipitate, especially in the form of dolomite. On the other hand, the evaporative minerals are still undersaturated. The bacteriological quality and the water quality index (WQI) of this area are considered to be generally good to poor quality, with the exception of a few points, near the public dump of Almis Guigou, plateau of Lamrijate (Timahdite), Aït Hamza and Aït Ghanem, that show significant bacterial contamination and high concentrations of sodium, chlorides and nitrates. According to the calculation of the (Na%), the (SAR) and (PI), the groundwater samples are suitable for irrigation.

Abstract Fifty groundwater samples were obtained pre and post-monsoon seasons in parts of hard rock terrain in Andhra Pradesh, South India, in order to assess the drinking water quality. PIG values of groundwater samples ranged from 0.95–1.53 and 0.83–1.28 during pre and post-monsoon seasons. PIG values are slightly higher in the pre-monsoon season when compared to the post-monsoon season. In the pre monsoon season, 96% of the groundwater samples showed insignificant pollution class (

Flooding is the most frequent natural hazard globally, but evidence of its impact on domestic water point contamination remains limited. This study aimed to assess dam-related flooding's impact on microbiological contamination of rural water points and to evaluate agreement of satellite-derived flood maps with ground-based observations of water point flooding. Fieldwork took place in two Ghanaian districts frequently flooded following dam overspill. Fifty-seven water points were tested for bacterial parameters during and immediately after flooding. Forty water points were resampled in the dry season, with the remainder having run dry. Ground-based observations of flooding were compared with three satellite-derived flood maps. Boreholes were less contaminated than wells or surface waters (geometric mean E. coli = 20.2, 175.6, and 590.7 cfu/100 ml, respectively). Among groundwater points, a Wilcoxon signed-rank test indicated significantly greater median E. coli and thermotolerant coliform contamination during flooding (p = 0.025 and p < 0.001, respectively), but Shigella, salmonella, and intestinal enterococci counts were not significantly different between seasons. In contrast, among surface water points, E. coli, Shigella, and Salmonella counts were significantly greater in dry season samples (p < 0.005 for all parameters), possibly reflecting a "concentration" effect. Satellite-derived flood maps had no or low agreement with ground-based observations of water point flooding. Although groundwater quality deteriorated during and after flooding, surface waters were the most microbiologically contaminated in both seasons. The greatest public health risk thus occurred where households switched to surface water collection during or following flood season. Flood risk should be assessed before borehole installation and existing flood-prone boreholes remediated to mitigate population exposure to contaminated water. [ABSTRACT FROM AUTHOR]

Evaluating grouLindwater quality and associated hydrochemical properties is critical to manage groundwater resources in arid and semiarid environments. The current study examined groundwater quality and appropriateness for agriculture in the alluvial aquifer of Makkah Al-Mukarramah Province, Saudi Arabia, utilizing several irrigation water quality indices (IWQIs) such as irrigation water quality index (IWQI), total dissolved solids (TDS), sodium adsorption ratio (SAR), potential salinity (PS), magnesium hazard (MH), and residual sodium carbonate (RSC) assisted by multivariate modeling and GIS tools. One hundred fourteen groundwater wells were evaluated utilizing several physicochemical parameters, which indicating that the primary cation and anion concentrations were as follows: Na+ > Ca2+ > Mg2+ > K+, and Cl− > SO42˗ > HCO3˗ > NO3˗ > CO32˗, respectively, reflecting Ca–HCO3, Na–Cl, and mixed Ca–Mg–Cl–SO4 water facies under the stress of evaporation, saltwater intrusion, and reverse ion exchange processes. The IWQI, TDS, SAR, PS, MH, and RSC across two studied regions had mean values of 64.86, 2028.53, 4.98, 26.18, 38.70, and − 14.77, respectively. For example, the computed IWQI model indicated that approximately 31% of samples fell into the no restriction range, implying that salinity tolerance crops should be avoided, while approximately 33% of samples fell into the low to moderate restriction range, and approximately 36% of samples fell into the high to severe restriction range for irrigation, implying that moderate to high salt sensitivity crops should be irrigated in loose soil with no compacted layers. The partial least squares regression model (PLSR) produced a more accurate assessment of six IWQIs based on values of R2 and slope. In Val. datasets, the PLSR model generated strong estimates for six IWQIs with R2 varied from 0.72 to 1.00. There was a good slope value of the linear relationship between measured and predicted for each parameter and the highest slope value (1.00) was shown with RSC. In the PLSR models of six IWQIs, there were no overfitting or underfitting between the measuring, calibrating, and validating datasets. In conclusion, the combination of physicochemical characteristics, WQIs, PLSR, and GIS tools to assess groundwater suitability for irrigation and their regulating variables is beneficial and provides a clear picture of water quality. [ABSTRACT FROM AUTHOR]

Groundwater (GW) is an important source of freshwater in arid and semiarid areas. Some important industrial activities, such as coal mining, also consume GW. There have been few studies evaluating GW quality in the Selian coal mining area of Inner Mongolia. This study aimed to identify the hydrochemical phases and the sources of main ions in the GW of the Selian coal mining area. Water quality analysis was performed on 20 shallow GW samples collected from the study area. Statistical correlation analysis was performed on these water quality data. The quality of irrigation water was evaluated based on water quality indices such as the sodium absorption rate and sodium percentage. The risk of nitrate pollution in the study area to human health was evaluated by GW nitrate content. The results show that the dominant GW chemistry types in the study area are the mixed and Ca–HCO3 types. Correlation analysis indicates that rock weathering and leaching are the main natural drivers of GW hydrochemistry in this area. The irrigation risk analysis shows that GW in this area can be used for irrigation, although some caution is needed. The human health risk assessment shows that GW nitrate pollution poses more risk to children than to adults by a factor of 1.168. It is recommended that centralized treatment of drinking water is the optimal approach to managing this risk. The results of this study can act as a reference for the rational use of GW and for control of nitrate pollution in this area. [ABSTRACT FROM AUTHOR]

Abstract Population, salinity, and increasing water consumption have caused high pressure on groundwater resources in Iran. The study reported here investigates the change of groundwater quality in Zrebar lake basin and the relationship between it with land-use change and precipitation rate from 1992 to 2018. To achieve the intended goal, chemical parameters of water from wells around the lake, bicarbonate (HCO3−), sulfate (SO4), sodium absorption ratio (SAR), and electrical conductivity (EC) were analyzed. Then, four methods including interpolation in the ArcGIS environment, Wilcox and Schoeller Diagram in Aq.QA software and Ground Water Quality Index (GWQI) were used to indicate the trend of water quality from 1992 to 2018. To detect land-use changes from 1992 to 2018, three Landsat satellite images covering the study area were used to identify land uses and their changes during the period that shows a significant area of forests that has been replaced by agricultural use, the dominant cover in 2018, while the area of forest has declined sharply. In this study, the precipitation patterns over the past years were showed to assess the relationship between rainy and low rainfall years with water quality. The results showed that forest area in 1992, 2003 and 2018 was 70.6, 62.5 and 50.2 hectares, respectively, which shows a significant reduction, 22%, during this study period. On the other hand, the area of farmlands and human-made constructions has increased by 20% and 200%, respectively. This study additionally revealed that although there was a decreasing trend in the rate of rainfall and the agricultural lands have increased, the quality of water was still suitable for drinking and agriculture consumptions. Changes in groundwater quality were not justifiable by rainfall rate and land-use change because there was no significant relationship between them with all the groundwater quality parameters.

Abstract The municipality of Santa Ignacia in the Province of Tarlac is highly dependent on groundwater as its major water supply for various purposes, but there is inconsistency in monitoring groundwater quality in the area which may impact the health of consumers. This study presented the preliminary assessment of groundwater quality through the application of spatial mapping. Out of 6,815 wells in the municipality, groundwater samples were collected from 274 hand pump wells. The measurements of selected groundwater quality parameters such as pH, conductivity, nitrate, nitrite, and iron of groundwater samples were determined on-site. The geographical coordinates of sampled wells and measurements of groundwater quality parameters were used in Geographic Information System software, QGIS, to construct the spatial distribution and spatial variation maps. The values of measured parameters were interpolated using the inverse distance weighted technique to predict the parameters at other sites in Santa Ignacia. Spatial variation maps revealed that the groundwater quality parameters varied in the municipality. All measured parameters, except the nitrite content, were within the acceptable limits set by the World Health Organization for drinking water. The high level of nitrite content in groundwater may be attributed to the application of fertilizers during agricultural activities. The nitrite content of groundwater, which exceeded the permissible limit, may cause long-term public health problems. Hence, an upscale evaluation and monitoring of groundwater quality and existing anthropological activities in the municipality are highly recommended. The identification of other possible source(s) of nitrite is necessary to lessen possible contamination risk and to protect the groundwater sources in the municipality. The results of this preliminary study would be useful in prospect studies of groundwater quality in the study area and in other provinces in the Philippines.

This study reports the significance of freshwater springs primarily in meeting drinking water demands besides offering various ecosystem services. We analyzed a total of eighteen geochemical quality parameters using standard methods from various representative springs of Anantnag district, Kashmir Himalaya. Groundwater quality profiles were generated in a GIS environment for each parameter. Additionally, statistical methods were employed to understand the interdependence of water quality parameters. Highly variable dissolved oxygen (0.4–9.2 mg L−1) and relatively higher values of nitrate ranging from 57 to 2668 µg L−1 noticed during the study may be mostly related to contamination from agricultural waste. The findings of this study revealed that the springs are predominantly hard water type as the water samples found were calcium-rich and exhibited higher total phosphorus in few samples owing to limestone lithology in the catchment. Principal Component Analysis (PCA) to the data generated chiefly three components (VF1, VF2, and VF3) having Eigen values of 2.0 or more (2.28–5.37) contributing for 31.63%, 17.99% and 13.44% of the total variance, respectively. The water quality index (WQI) of the samples for drinking purpose ranged from good to excellent. In light of our findings, it is argued that springs offer a potential, although partial, solution to the drinking water demands of a burgeoning population in Indian Himalayan region. However, equally important is to have a thorough investigation of springs to explore the impacts of other forms of pollution, including heavy metals, pesticides and antibiotic wastes, which can diminish much-needed ecosystem services. [ABSTRACT FROM AUTHOR]

Groundwater is a vital natural resource in the Kathua region of the Union Territory of Jammu and Kashmir, Northern India, where it is used for domestic, irrigation, and industrial purposes. The main purpose of this study was to assess the hydrochemistry of the groundwater and to determine its suitability for drinking, irrigation, and industrial uses in the Kathua region. In this study, 75 groundwater samples were collected and analyzed for the physicochemical parameters such as electrical conductivity (EC), total dissolved solids , pH, and various cations and anions. The analyzed data were computed for designing groundwater quality index to know the suitability for drinking purposes. The EC, sodium percentage, permeability index, and magnesium hazard were assessed to evaluate groundwater suitability for irrigation. Further, the corrosivity ratio was assessed to find the groundwater quality criteria for industrial purposes. The comprehensive results obtained from the water quality index indicate that almost all groundwater samples are suitable for drinking. The ionic abundance is in the order of Ca2+ > Na+ > Mg2+ > K+ for cations, and HCO3− > SO42− > Cl− > NO3− for anions, respectively. The Piper diagram shows that hydrochemistry of the groundwater is dominated by alkaline earth metals (Ca2+, Mg2+) and weak acids (HCO3−). According to the Gibbs diagram, the chemistry of groundwater is mainly controlled by the rock–water interaction process, indicating that most of the groundwater samples of the area are of bicarbonate type. The EC results classify the groundwater as excellent to good; the sodium percentage also indicates that the water is fit for irrigation. According to the Wilcox and USSLS diagrams, and permeability index, a majority of samples are suitable for irrigation with a few exceptions. The magnesium hazard depicts that there are few samples (19%), which are unsuitable for irrigation. According to the corrosivity ratio, 65 samples are safe for industrial use while the remaining 10 samples are considered to be unsafe. Thus, it is found that most of the groundwater in the area can be used for drinking, irrigation, and industrial purposes. [ABSTRACT FROM AUTHOR]

This study investigates the risk to contamination of groundwater in public water supply wells in the Koprivnica-Križevci county (northwest Croatia). Five physicochemical parameters were monitored in all groundwater samples from 2008 to 2017 to identify major differences between the wells, assess temporal variations and understand the capacity for rainfall to alter groundwater pollution loadings. Multivariate discriminant analysis showed statistically significant differences between the six sampled wells based on the analyzed parameters (Wilks' lambda: 0.001; F = 26.2; p < 0.0000). Principal component analysis revealed two significant factors, including factor 1 which explained 32.8% of the variance (suggesting that the quality of the groundwater was mainly controlled by nitrate) and factor 2, accounting for 16.2% of the total variance (which corresponded to KMnO4/oxidizability and to a lesser extent, pH). The time series data showed disparate trends, with nitrate concentrations increasing, whereas pH and KMnO4 decreased, while electrical conductivity and chloride levels remained stable. Although rainfall can impact groundwater pollution loadings through dilution processes in aquifers, the resulting fluctuations in physicochemical parameters are complicated by variations in rainfall events and local topography, as well as from climate change. Therefore, it is important to predict the contamination of groundwater quality in the future using machine learning algorithms using artificial neural network or similar methods. Multivariate statistical techniques are useful in verifying temporal and spatial variations caused by anthropogenic factors and natural processes linked to rainfall. The resulting identified risks to groundwater quality would provide the basis for further groundwater protection, particularly for decisions regarding permitted land use in recharge zones. [ABSTRACT FROM AUTHOR]

Groundwater pollution is one of the most important challenges for human. In many parts of the world, groundwater is used for agriculture and even drinking, whereas natural and human-made groundwater contaminants have also affected the quality of these waters. Therefore, monitoring and evaluating the quantity and quality of groundwater is very important. In this research, the efficiency of finite element method (FEM) for groundwater flow and Sulfate concentration transport modeling has been investigated for a 7-year period. After finite element validation analysis, this method was employed in a hypothetical and real-case aquifer with regularly distributed nodes and square elements 200 m × 200 m. The mean error and root mean square error (RMSE) as performance criteria were used to evaluate the performance of the model. The results indicated that the FEM model with RMSE = 1.06 (m) and 1.44 (me/lit) has good skills in groundwater flow and contaminant transport modeling, respectively. Also, the results of the FEM model indicated that in the northeast of the aquifer, the groundwater level is low and the amount of Sulfate is high (higher than the standard values recommended by) which is also confirmed by real data. [ABSTRACT FROM AUTHOR]

Tazerbo water wellfield, located in southeast Libya, was constructed as part of the first stage for the Man-Made River Project (Eastern System) during 1995–2003. A group of land subsidence forms was discovered approximately 30 km north of the wellfield two years after production, which began in March 2004. The wellfield production rate is only about one-third of its designed capacity. In addition to the land subsidence, there is a problem with the natural groundwater quality represented by high iron and manganese concentrations. This research aims to characterize the aquifer system and assess the current condition of the wellfield since its operation in 2004 in terms of groundwater quality and quantity. It further evaluates current groundwater management practices. The geographic information system was used to map hydrogeologic data of drilled water wells and groundwater monitoring data from 2003 to 2019. The aquifer system characterization showed that the exploited aquifer has excellent hydraulic properties and promising potential for future groundwater utilization. The measured drawdown during 2019 shows a maximum decline of 28 m. Moreover, the average water production is about 322,270 m3/ day, equivalent to 32% of the total abstraction proposed to the end of the year 2020 of about 1907 million m3. As far as Groundwater quality is concerned, there has been no change in water quality since the beginning of abstraction. This research indicates that current policy and institutional approaches and practices promote the optimum management of the wellfield's water resources. [ABSTRACT FROM AUTHOR]

Fluoride contamination in groundwater is known from different villages of Talupula Mandal. In the present study in part of SoI toposheet no.57 J/8) of Ananthapuramu district, Andhra Pradesh, the magnitude and credible geogenic sources of the fluoride contamination in groundwater are studied. The present study carried out includes 30 groundwater samples covering an area of 442.89 sq km using (GIS) and (CCME-WQI) techniques. Problem is causally related to fluoride intoxication of human beings and animals through drinking waters. Well waters in the Talupula Mandal surrounded areas carry a high level of fluoride concentrations, much above the internationally decided safety limits. 'Fluorosis' is imminent as a result of prolonged intake of waters with more than 1 to 1.5 ppm of fluoride. Fluoride testing results of groundwater from borewell pump using fluoride test kit reveal that about 50% groundwater samples show fluoride concentration more than 4.0 mg/l, 30% samples show between 2.0 and 3.0 mg/l and 20% samples show fluoride concentration is 1–2 mg/l and above (BIS permissible limit: 1.5 mg/l). Agriculture indices are as follows: sodium percentage (Na%) was found between ranges (20.04–55.26), sodium absorption ratio varies from 0.86 to 3.91), Kelly's ratio (KR) varies from 0.22 to 1.16, residual sodium carbonate varies from − 4.12 to 20.66), permeability index (PI) varies from 39.00 to 82.28, magnesium hazard varies from 52.83 to 85.47, potential salinity varies from (0.71–3.15); results shown that the majority of the groundwater samples were suitable for irrigation uses. According to Gibbs' ratio samples Gibbs ratio 1 (0.04–0.45) and Gibbs ratio 2 (0.44–0.81) fall in the rock dominance. Major ion compositions plotted on a Piper tri-linear diagram indicate that the water is of Ca-HCO3 type and is mixed Ca–Mg–Cl type. The present study indicates that the groundwater chemistry is mostly controlled by geogenic processes (weathering, dissolution and ion exchange) and some extent of anthropogenic activities. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the geochemical processes controlling the groundwater chemistry and also to assess the groundwater quality suitability criteria for irrigation purposes. An agricultural region of Telangana, South India, was selected for the present study. A total of 100 groundwater samples were collected and estimated for pH, electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate ( HCO 3 - ), chloride (Cl−), sulfate ( SO 4 2 - ), nitrate ( NO 3 - ), and fluoride (F−). The groundwater was characterized by mostly alkaline conditions with a dominance of Na+ and HCO 3 - ions, indicating the prevailing conditions of weathering and dissolution of silicate minerals. The various geochemical signatures such as Na+ vs Cl−, Ca2+ + Mg2+ vs HCO 3 - , Ca2+ + Mg2+ vs HCO 3 - + SO 4 2 - , HCO 3 - vs Cl− + SO 4 2 - , Ca2+ + Mg2+ vs total cations, and Ca2+ + Mg2+ vs Na+ + K+ and the saturation indices with respect to calcite, halite, and gypsum suggest obviously the dominant conditions of carbonate weathering associated with the reverse ion exchange and evaporation processes as the geogenic factors. The linear trend of TDS vs NO 3 - + Cl−/ HCO 3 - clearly specifies the influence of non-geogenic sources on the aquifer system. These are the important contributors to the variation in the groundwater chemistry. However, the impact of the geogenic source is masking the influence of the anthropogenic source in some areas of the present study region. According to the salinity vs sodium adsorption ratio, residual sodium carbonate, magnesium ratio, and Kelly ratio, 99.9%, 7.06%, 63.07%, and 51.27% of the total study region come under the unsuitable categories for irrigation purposes, respectively. Therefore, the findings of this study recommended some site-specific appropriate management strategies for the safe supply of groundwater for proper crop growth and consequently for sustainable development of the rural environment. [ABSTRACT FROM AUTHOR]

Abstract Groundwater is the major resource for drinking and irrigation purposes in urban areas of Abaya-Chemo sub-basin of Great Rift Valley, Ethiopia. There is an incredible increase in demand in the sub-basin for good-quality groundwater resources. However, the exhaustive irrigation and rapid urbanization has posed a serious threat to groundwater quality in the urban districts of sub-basin like Arba Minch town. The aim of the study was to evaluate the groundwater quality status and to map their spatial distribution with respect to the suitability for drinking and irrigation purposes in Arba Minch town, Ethiopia. Fourteen bore well samples were examined for geochemical variations and groundwater qualities. The spatial distribution maps of quality parameters were prepared using the kriging method in ArcGIS 10.3. Drinking water quality index, sodium adsorption ratio (SAR), percentage sodium (Na%), residual sodium carbonate (RSC), and permeability index (PI) were considered for drinking and irrigation suitability assessment. Comparison of the hydrochemical results with the World Health Organization (WHO) and Ethiopian drinking water standards (ES) and various classifications revealed that the current status of the groundwaters is suitable for drinking and irrigation purposes except for a few sites at the northwestern part of the study area. The WQI results revealed that 7% and 64% of samples fall from excellent to good classes for drinking categories. Irrigation indices also demonstrated that 80% of samples fall in good classes for irrigation purposes. About 75 percent of samples belong to Ca–Mg-HCO3 facies, and the reaming samples belong to Ca–Mg–Cl facies. The results of the study concluded that the proposed approach is reliable and efficient for the groundwater pollution status evaluation and can also be applied in decision making for effective groundwater resources monitoring in the study area.

Abstract In recent years, groundwater pollution has become increasingly a serious environmental problem throughout the world due to increasing dependency on it for various purposes. The Damodar Fan Delta is one of the agriculture-dominated areas in West Bengal especially for rice cultivation and it has a serious constraint regarding groundwater quantity and quality. The present study aims to evaluate the groundwater quality parameters and spatial variation of groundwater quality index (GWQI) for 2019 using the fuzzy analytic hierarchy process (FAHP) method. The 12 water quality parameters such as pH, TDS, iron (Fe−) and fluoride (F−), major anions (SO4 2−, Cl−, NO3 −, and HCO3 −), and cations (Na+, Ca2+, Mg2+, and K+) for the 29 sample wells of the study area were used for constructing the GWQI. This study used the FAHP method to define the weights of the different parameters for the GWQI. The results reveal that the bicarbonate content of 51% of sample wells exceeds the acceptable limit of drinking water, which is maximum in the study area. Furthermore, higher concentrations of TDS, pH, fluoride, chloride, calcium, magnesium, and sodium are found in few locations while nitrate and sulfate contents of all sample wells fall under the acceptable limits. The result shows that 13.79% of the samples are excellent, 68.97% of the samples are very good, 13.79% of the samples are poor, and 3.45% of the samples are very poor for drinking purposes. Moreover, it is observed that very poor quality water samples are located in the eastern part and the poor water wells are located in the northwestern and eastern part while excellent water quality wells are located in the western and central part of the study area. The understanding of the groundwater quality can help the policymakers for the proper management of water resources in the study area.

Abstract In this study, hydrogeochemical processes controlling groundwater chemistry and groundwater quality were investigated. Drinking water is supplied from groundwater (mostly spring and well water) in the study area. The various parameters such as physicochemical parameters, major ions, trace elements and nitrogen derivatives of groundwater samples of were analyzed. These analysis results are compared with drinking water standards for suitability and it does not exceed the permissible limit values, except for the As and F contents of some samples. The results of major ion chemistry of groundwater in the Yalvaç–Gelendost basin suggest that the silicate weathering and ion exchange are the main controlling hydrogeochemical processes in the variation of groundwater quality. The water types are Ca–Mg–HCO3, Mg–Ca–HCO3 and Ca–HCO3 in the basin. Non-carcinogenic health risk assessment associated with arsenic, nitrate and fluoride was assessed by oral (ingestion) and dermal pathways for adult and child. For child, hazard coefficient and hazard index values are less than 1, and a negative effect on usage as drinking water and dermal (skin contact) absorption not expected. But, potential non-carcinogenic effect with oral intake is likely to occur for some water samples for adults. In addition, carcinogenic risk of As element was evaluated for adults and child related to oral and dermal effect. The carcinogenic risk of As through oral intake may pose health risks for children. For adults, it has been determined that water ingestion with dermal exposure may cause cancer. Arsenic is the main toxic element for human health in the study area. The content of As decreases in seasonal water samples. In this case, the negative effect of arsenic intake with ingestion and dermal pathways on health decreases.

Hydrogeochemical and multivariate assessment of groundwater samples of the Churachandpur sub-division of the state of Manipur was carried out to study its suitability for potable and irrigational uses. The study extensively discusses the underlying hydro-geochemistry using multivariate geostatistical tools for physicochemical parameters of 35 spatially distributed groundwater samples during pre- and post-monsoon seasons. In situ parameters (pH, TDS, DO, EC, salinity, ORP) were assessed in field conditions, and it was found that few samples exceed concentration than the prescribed standards. Both positive and negative ORP values and low DO levels of the samples indicate oxidizing and reducing aquifers due to recent unstable geologic formations. Although the concentration of Cl−, SO42−, and NO3− is well within desirable levels, the concentration of F− and As3+ of a few samples exceeds the prescribed standard. The water quality index of the groundwater samples signifies that more than 50% of samples are unsuitable for potable uses for both seasons. The geochemical analysis indicates that most of the water is Ca–Mg–Cl–HCO3 type followed by Mg–Ca–Cl–HCO3 types in both the seasons and dominated by the rock-weathering geochemical process. Multivariate analysis and geostatistical mapping highlight the spatial variability of water quality parameters and possibilities of the occurrence of geogenic contaminants in the aquifers of the study area. [ABSTRACT FROM AUTHOR]

Groundwater withdrawal at very fast rate poses threat on existing groundwater resources in different parts of the world. This reduction in groundwater levels significantly disturbed the natural aquifer flow rate and thereby different hydrogeochemical processes, which may further impair the groundwater quality. The groundwater quality in rural area of Chhattisgarh State is degraded, and the problem of saline water poses health risk to people. In this research investigation, suitability of groundwater of Bemetara District, Chhattisgarh, India, has been evaluated for drinking purpose through water quality index (WQI) method and principal component analysis (PCA). Total 116 groundwater samples were collected during the pre-monsoon (June 2019) and post-monsoon season (December 2019) and analyzed for physicochemical parameters. Total dissolved solids ranged from 250 to 10,440 mg/L and 289 to 3583 mg/L during pre-monsoon and post-monsoon, respectively, and 55% of the total samples exceeded acceptable BIS limit in pre-monsoon, while about 66% samples exceeded in post-monsoon season. SO42− concentrations varied from 3 to 5734 mg/L during pre-monsoon and 4.5 to 2002 mg/L during post-monsoon, respectively. Total 28% samples in pre-monsoon and 18% samples in post-monsoon season exceeded the maximum permissible BIS limit (400 mg/L) of SO42− ion in the study area. On the basis of WQI, the quality of groundwater varies from "Excellent water" to "Good water" category. The groundwater of northeastern part of the district is not suitable for drinking, and therefore, it is recommended to treat this groundwater before human consumption with special reference to SO42− contamination. PCA inferred that four components are sufficient to explain the variance in chemistry of groundwater that is mainly governed by dissolution of gypsum mineral, other rock–water interaction and anthropogenic activities. Further, water quality was improved in the direction of groundwater flow in the study area, establishing a direct relationship between groundwater flow and water quality of the Bemetara District. This study provides very useful database to design sustainable groundwater management plan for the district. [ABSTRACT FROM AUTHOR]