Majority Of Water Samples Research Articles

Comparative Analysis of Using Water Quality in Urban Areas of Duhok City, Iraq

Water is sourced from various locations, including lakes, wells, artificial reservoirs, and rivers. Contamination of these sources poses a significant threat to human health, highlighting the need to monitor water quality. This study focuses on evaluating the water quality in the Duhok governorate of the Kurdistan region, Iraq, by analyzing several key physicochemical parameters: turbidity, pH, total dissolved solids (TDS), electrical conductivity (EC), total alkalinity (TAL), total hardness (TH), calcium (Ca²⁺), magnesium (Mg²⁺), chloride (Cl⁻), sulfate (SO₄²⁻), nitrate (NO₃⁻), sodium (Na⁺), and potassium (K⁺). Over a period spanning from January 2019 to December 2021, a total of 1,374 water samples were collected from different sources, including reservoirs, deep wells, springs, the Duhok dam, and the water supply network within the Duhok governorate. The analysis revealed that parameters such as turbidity, pH, TH, Ca²⁺, Mg²⁺, SO₄²⁻, NO₃⁻, and Na⁺ varied significantly across the three years studied. In contrast, other parameters like TDS, EC, TAL, Cl⁻, and K⁺ showed no significant fluctuations. The results also indicated a decrease in most physicochemical parameter values in 2021 compared to 2019 and 2020, with the exception of turbidity. Overall, the majority of water samples were found to be within safe drinking limits. Ongoing monitoring of these water sources is essential to detect any variations in water quality promptly.

Hydrogeochemical evaluation and characterization of water quality in the Phewa Lake, Pokhara, Nepal.

The study was carried out in the Phewa Lake of Pokhara Metropolitan City, Gandaki Province, Nepal, for geochemical assessment and characterization of the lake water quality. A total of 28 water samples were collected in each season from the different zones of the lake in March 2022 (pre-monsoon) and November 2022 (post-monsoon). The lake exhibitedelevated levels of PO43-, NO3-, and NH3, indicating that anthropogenic activities are interfering the lake water. The significant differences in many monitored physicochemical parameters between the pre- and post-monsoon visualize dilution effect in the lake during post-monsoon. Piper diagram illustrates that the majority of water samples in the lake are of Ca-HCO3 type. Additionally, Piper diagram, Gibbs diagram, and Mixing plot illustrate that carbonate weathering is dominant in both seasons. Principal component analysis (PCA) reveals significant correlations among NO3-, SO42-, Na+, and Cl-, demonstrating that pollution in the lake water is attributed to agricultural activities and domestic effluents. In the majority of samples,water quality index (WQI) depicts that the lake water quality is very poor to poor in the pre-monsoon and poor to good in the post-monsoon. Sodium absorption ratio (SAR), % Na (percent sodium), electrical conductivity (EC), cation ratio of soil structural stability (CROSS), and United States Salinity Laboratory (USSL) diagram illustrate that the lake water is suitable for irrigation.

Study of the quality index of groundwater (GWQI) and its use for irrigation purposes using the techniques of the geographic information system (GIS) of the plain Nekor-Ghiss (Morocco)

Groundwater is an indispensable source of water for drinking water supply, agriculture and industry worldwide. In arid and semi-arid regions, groundwater has seriously deteriorated in recent decades due to environmental changes, anthropogenic activities and marine intrusion. A total of 79 groundwater samples from the Nekor-Ghiss plain were sampled for major chemical ion analysis. These analyzes showed that the water samples were highly mineralized (>1,500 mg/L), with hardness (83.5% of the samples were very hard) and high concentrations of chemical elements, such as Cl−, Mg2+, Na+ and SO42-. To assess the quality of water in the study area for irrigation and consumption purposes, we used the quality index (GWQI) as well as a multi-criteria analysis based on “geographic information system” by assigning a weight to the different water quality parameters. Also, Piper and Durov diagram was investigated. The results of the study were focused on the water quality parameters of the collected groundwater samples, such as the sodium adsorption rate (SAR), the percentage of soluble sodium (Na%), the Residual Sodium Carbonate (RSC) and Permeability Index (PI) Majority of water samples in the study area are suitable to be used for irrigation. Magnesium Risk (MH) and Kelley’s Ratio Kelly ratio. 51.9% unsuitable samples to 59.49% good samples for irrigation purposes. Monitoring the quality and quantity of groundwater is crucial for the effective and sustainable management of this valuable resource. According to the results obtained, it appears that 92% of all the samples are located in the domain of frequent recharge waters of limestone and dolomitic aquifers, namely, Ca-Mg-HCO3. About 8% of the samples measured have a composition of the Ca-Na-Mg-HCO3 type.

Evaluation of Drinking Water Quality From Water Coolers in Makkah, Saudi Arabia.

The quality of drinking water is an important health issue in crowded cities, so that an adequate drinking water with good quality must be provided, hence over hundreds of water coolers are distributed in Makkah city to cope with the increasing demand for drinking water. The present study aimed to determine the chemical and microbial quality of drinking water from coolers in Makkah city. Sixty-three samples from randomly selected water coolers were tested for chemical and bacteriological quality. For all samples, the mean value of physiochemical tests of pH (7.12), TDS (152.7 ppm), turbidity (2.56 NTU), free chlorine (0.312 ppm), fluoride (0.112 ppm), chloride (25.7 ppm), bromide (0.123 ppm), nitrate (0.616 ppm), sulfate (8.36 ppm), lithium (0.134 ppm), sodium (17.6 ppm), potassium (1.42 ppm), magnesium (1.95 ppm), calcium (19.2 ppm), chromium (0.025 ppm), cadmium (0.0026 ppm), and lead (0.0244 ppm) did not exceed the reference values of the drinking water regulations. The total coliform count was detected in 3.2% of the water samples. For total coliform count, the MPN in the majority of water samples (96.8%) was excellent while for E. coli count, the MPN in all water samples (100%) was excellent. Bacteriological quality has shown that no Pseudomonas, Salmonellae, or Legionellae species contamination detected. It was concluded that, the drinking waters in coolers in Makkah city were complied with international standards and within the acceptable limit. It is worth to continue periodic inspection and maintenance for the drinking water coolers during mass gatherings.

Investigating the relationship between groundwater augmentation and water quality in the 6000 ha watershed in Telangana state, India

Groundwater augmentation through rainwater harvesting has become a prime strategy to address water security and cope with the impact of climate change, especially in semi-arid regions. Increased water availability due to groundwater augmentation and its impact on rainfed agriculture has been well documented, but its impact on groundwater quality was rarely explored. In this study, data collected over 33-months on groundwater quality and groundwater table from a micro-watershed spread over 6000 ha in the semi-arid region of peninsular India were explored to assess the association between rainfall, groundwater augmentation, and groundwater quality. It was observed that the groundwater augmentation and related changes in the groundwater levels were influenced by the density of rainwater harvesting structures, rainfall distribution during the rainy season, groundwater withdrawals around the monitoring wells, and the distance between the wells and water storage structures. The results of principal component analysis (PCA) and hierarchal clustering revealed that the spatial and temporal variations in the groundwater quality governed by hydrogeochemical processes and preferential flow recharge processes might have been affected by groundwater augmentation and withdrawal. The fertilizer use in croplands as a non-point source of NO3–N and NH4–N in groundwater was affected by rainfall distribution. The high NO3–N levels in the vicinity of a burial site had indicated a possible point source of groundwater contamination. About 5%, 76%, 20%, and 4% of water samples were classified as poor, marginal, fair, and good as per the guidelines for drinking water with high fluoride and NH4–N content in groundwater as a point of concern. The majority of water samples were also classified as high salinity and low sodium hazard water, which may cause salt build-up in the poorly drained soil and affect crop water availability.

Characterization of groundwater in the arid Zenaga plain: Hydrochemical and environmental isotopes approaches

The Zenaga inlier, located in an arid area in southeastern Morocco, is mostly characterized by igneous and metamorphic fractured rocks. The surface water is quasi-absent and local populations (95% rural) are entirely dependent on groundwater resources for drinking and irrigation purposes. To evaluate the main factors controlling the origin and salinization of groundwater resources, we have investigated the chemical and stable isotope compositions of 23 groundwater samples. In addition, water quality assessment parameters including sodium absorption ratio (SAR) and water quality index (WQI) were also calculated. The results show that the majority of wells and boreholes are characterized calcium bicarbonate water type (78% of samples), with the following ionic sequence Ca2+>Na+ >Mg2+ >K+, and HCO3−> Cl−>SO42−>NO3− for cations and anions, respectively. A significant enrichment on major ions is steadily rising with depth as the water type changes toward calcium chloride. The interpretation of hydrochemical data suggests that the silicate weathering, cation exchange and evaporites dissolution are responsible for the groundwater chemistry. The majority of water samples are good to permissible for irrigation and poor to good for drinking purposes. The mineral salts found at greater depths degrade groundwater quality. In some areas, nitrate contents imply anthropogenic contamination derived especially from traditional septic tanks. Stable isotopes δ18O and δ2H reveal a distinction between the shallow aquifer and deep circulations. The uncommon depleted isotope signature found in deep circulations was associated with cold altitudes recharge, whereas the heaviest groundwater observed in shallow aquifer was interpreted as the contribution of surface water from Taghdout Dam. The Anti-Atlas Mountains and Siroua Massif's high altitude served as a source of recharge. The mixing at considerable depths and along the groundwater path appears to decrease the isotopic variability in the shallow and deep groundwater.

Heavy Metal Concentration in Surface Water around the Industrial Area M.I.D.C. Mahad, Maharashtra, India

The surface water quality in Mahad M.I.D.C.’s industrial area was analysed; it is used for irrigation and domestic purposes, so the quality of water must be assessed. Rapid industrialization and growing urbanization are the predominant factors responsible for the progressive stress on the area’s water. As a result, in light of this serious issue, the current study was undertaken to assesses surface water pollution caused by heavy metals. Throughout the year, water samples were obtained from Nalas and river located across the industrial area at one-month intervals. Using an Atomic Absorption Spectrophotometer, the heavy metals iron, copper, zinc, manganese, nickel, chromium and cobalt were determined (Perkin Elmer make model No. Aanyst 200). A comparison of surface water with WHO (1993) and BIS (1991) recommendations reveals that the majority of water samples contain heavy metal concentrations below the maximum permissible level.

Groundwater quality and its suitability for different uses in lower Djendjen Watershed, Northest Algeria

Groundwater is a vital resource in coastal areas to supply domestic, drinking, irrigation and industrial needs. To study the hydrogeochemical characteristics of groundwater and their suitability, Thirty-one (31) groundwater samples were collected from the shallow tubewells in the plain of the Djendjen river (North-East of Algeria). The water quality assessment has been carried out by evaluating the physicochemical parameters such as temperature, pH, EC, major ions i.e., Ca2+, Mg2+, Na+, K+, Cl-, SO42-, HCO3- and nutrients (NH4+, NO2-, NO3-, PO43-). The chemical parameters plotted in Piper’s diagram show the dominance of two chemical facies “calcium and sodium chloride” and “calcium bicarbonate”. Based on the analytical results, groundwater in the area is found to be generally suitable for drinking. The organic pollution index (OPI) show that the water is generally in the good quality category with no organic pollution. Chemical parameters when plotted in the U.S. Salinity diagram indicate that waters are C2S1 and C3S1 types, i.e., medium to high salinity and low sodium which is good for irrigation. Four corrosion indices were calculated (The indices include the Langelier saturation index, Ryznar stability index, Puckorius scaling index, Larson). The result indicates the corrosive nature of the majority of water samples.

Evaluation of underground water quality for drinking and irrigation purposes in New Valley Governorate, Egypt

Abstract Underground water is the main and probably the only source of drinking and irrigation in New Valley Governorate (Egypt). To assess water suitability for such purposes, 30 well-water samples (80–1300m depth) were collected from three oases i.e., El-Kharga, Baris and El-Dakhla. The pH values of these waters ranged from 6.5 to 7.88. SO 4 2 − was the dominant anion in such waters while Ca2＋ was the dominant cation. Concentrations of both ions (SO 4 2 − and Ca 2 + ) exceeded the maximum allowable limits for drinking and irrigation purposes. Although sodium adsorption ratio (SAR) values did not exceed “10” in all waters samples; however, Mg-hazards and low infiltration rate might threaten the suitability of water for irrigation in many locations. Concentrations of Zn, Mn, Cu, Pb, Cd, As and Se were below the maximum allowable concentrations suggested by FAO for irrigation water. On the other hand, Fe was the only potentially toxic element (PTE) whose concentrations exceeded the permissible levels of WHO regulations for drinking water. According to the principal component analysis (PCA), these metals were originated from natural (Fe, Mn, Zn and Cu) and anthropogenic (As, Pb, Cd and Se) sources. Their existence represents potential chronic threats to children, particularly Fe, Mn, Pb and As. Moreover, the majority of water samples were within the moderate grade of irrigation quality index while exhibited low grades for the drinking quality index. Accordingly, more attention should be paid towards improving the quality of underground water in New Valley governorate for either drinking or irrigation purposes.

A Study on Distribution of Water Quality Parameters in Potable/Ground Waters of Visakhapatnam Coastal Region with Multivariate Factor Analysis

Chemical components of the earth crust influence the ground water quality. In addition, anthropogenic activities also contribute in deteriorating the quality of ground waters and contaminate the water sources. In present study, 22 water samples were collected from the potable/ground water sources in south coastal region of Visakhapatnam district, India during pre- and post-monsoon seasons and characterized for physico-chemical parameters viz., pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, oxidation reduction potential (ORP), dissolved oxygen (DO), temperature, total hardness (TH), total alkalinity (TA), bicarbonate, carbonate, chloride, fluoride, sulphate, nitrate, phosphate, calcium, magnesium, sodium and potassium. The distribution of parameters was explained by Box-Whisker plot. Further Piper diagrams were drawn to identify the geochemical expressions between the parameters. Multivariate factor analysis was used to assess the degree of factor loadings and to identify the group of parameters influencing the variance of different water quality parameters. The analytical data indicated that majority of water samples in the study area have higher concentration of TDS, TH, TA, Ca2+, Mg2+, Na+, Cl−, HCO3 − and F−.

Groundwater quality concern for wider adaptability of novel modes of managed aquifer recharge (MAR) in the Ganges Basin, India

Groundwater (GW) depletion and recurring floods have become a major concern among researchers and planners across the world. To rejuvenate stressed aquifer and moderate flood impacts, a modified version of managed aquifer recharge (MAR) consisting of a cluster of ten recharge wells (RWs) embedded in a community pond with an area of 2625 m2 and utilizing diverted floodwater was tested on a pilot scale in Ramganga sub basin, India. The approach could recharge a maximum of 72426 m3 of floodwater in 78 days during the wet season. The pond intervention minimized clogging of RWs by retaining maximum silt load of 68.01%. Hydro-geochemically, majority of water samples were of Mg-HCO3 and Ca-HCO3type. Ion exchange processes and weathering of carbonate and silicates were the controlling factors, determining water quality of the area. Total dissolved solids, fluoride, iron, zinc, manganese, chromium, cobalt, nickel, mercury, phosphate, nitrate, and ammonical nitrogen were found within the permissible limits as laid down by World Health Organization except arsenic and lead, which seems to be the inherent problem in the area, as evidenced by water quality analysis of farmers tube wells located upstream and down streams of the recharge site. The coliform presence in the 88.23% of sampled GW may thwart from direct use for drinking whereas it was fit for irrigation. Looking the benefits of modified MAR as a proactive GW quality improvement with good aquifer recharge, it is recommended for scaling up of the intervention across the GW stressed parts of the whole Ram Ganga basin and similar hydro-geological regions elsewhere.

Hydrochemical and Quality Assessment of Groundwater Resources in Al-Madinah City, Western Saudi Arabia

Fifty-four groundwater samples were collected from Hamra Alasad in Al-Madinah City. The chemical and microbial characteristics of the samples were analyzed and compared with their respective standards. The results revealed that 90.7% of the samples showed higher amounts of NO3. However, 59.3% of the samples were found unfit for irrigation purposes due to a high salinity hazard. Most of the groundwater samples were highly saline, yet no sodicity hazards were anticipated as predicted by sodium adsorption ratio (SAR). Generally, the soluble cations and anions, dissolved salts, boron, and NO3− exceeded the maximum permissible limits for drinking water in most of the samples; however, Pb, Cd, As, Zn, Cu, Ni, Co, Fe, Mn, and Cr were within the permissible limits. Furthermore, 42.6%, 24.1%, 18.5%, 14.8%, 1.9%, and 37.0% of the samples were infected by a total coliforms group, fecal coliform, Escherichia coli, Staphylococcus sp., Salmonella sp., and Shigilla sp., respectively. The water quality index revealed that 3.7% of the samples were good for drinking (class II), and 9.3% were very poor (class IV). The remaining samples were unfit for drinking (class V) due to high salinity and/or microbial contamination. Durov and Piper diagrams revealed that the majority of water samples were of the calcium sulfate–chloride type. Overall, 87% of water samples were inappropriate for drinking purposes, while 77.8% were unsuitable for irrigation.

Comprehensive integrated index-based geochemistry and hydrochemical analyses of groundwater resources for multiple consumptions under coastal conditions.

The primary objective of this study was to assess the quality of groundwater in the Guilan aquifer, a principal aquifer in the north of Iran, for drinking, irrigation, and industrial purposes. In this regard, groundwater samples have taken from a database provided by the Water Resources Authority of Guilan Province, Iran's Ministry of Energy. The studied four main regions of this aquifer were Talesh, Astaneh, Lahijan, and Foomenat. Achieved results were compared with the maximum permissible limit values recommended by the World Health Organization (WHO) and Food and Agriculture Organization (FAO) water standards for drinking and agricultural purposes, respectively. Moreover, evaluation of water suitability for industrial application was determined. According to the different indices, groundwater quality is suitable for irrigation purposes in all studied areas. A Piper diagram illustrated that the most dominant water type was Ca-HCO3 in the all studied areas. This result also is consistent with results from the analysis of mineral saturation index. Accordingly, the result of water quality index (WQI) revealed that the groundwater in the Guilan aquifer could categorize from excellent to poor quality classes. However, the majority of water samples in Astaneh region mostly fall into the poor water class. The calculation of corrosiveness and scaling indices as Ryznar stability index (RSI) illustrated that a large number of the samples could be classified into aggressive and very aggressive categories. The results additionally showed that tendency to form scale based on Puckorius scaling index (PSI) was observed in some groundwater samples. Overall, the status of groundwater quality in Talesh region was noteworthy better than the other studied regions, while Astaneh region is more vulnerable with elevated contents of ions and physicochemical parameters.

Study on irrigation water quality in some minor lift irrigation schemes and its impact on soil characteristics

The quality parameters of irrigation water in some minor lift irrigation schemes on Bhor nallah, Chatha farm at Gidergalion were evaluated and their impacts on soil characteristics in the fringe areas of Ranvir canal and non command were studied. Irrigation water samples at monthly intervals were collected and analyzed for pH, Electrical conductivity (EC), Sodium Adsorption Ratio (SAR), Magnesium Hazards (MH) and Residual Sodium Carbonate (RSC) by following standard methods. The soil samples from the concern command and adjoining areas (non command) were also collected and analyzed for important physico chemical properties and available nutrients as per standard procedures. Results revealed that majority of water samples collected from minor lift irrigation schemes on Bhor and Balal nallahs containing municipal/industrial waste was under high salinity-low SAR category, whereas water samples of Ranbir Canal at Gidergalian falls under medium salinity-low SAR. The soil characteristics viz. pH, EC, OC and available N, P and K were higher in command soils of Bhor and Chatha as compared to non command soils of Gidergalian and Dharap.

SELENIUM AND HEAVY METAL LEVELS IN VEGETABLES AND TISSUES OF THREE NON-MIGRATORY BIRDS EXPOSED TO SOIL, WATER, AND AQUATIC SEDIMENT CONTAMINATED WITH SELENIFEROUS RAŠA COAL

Coal mining and coal combustion release environmental contaminants which stay at emission sites for many decades. The paper reports total Se and heavy metals (As, Cd, Cu, Cr, Hg, Pb, Sr, U, V, and Zn) in lettuce, potato, and tissues (liver, kidney, heart, and muscle) of three non-migratory bird species (pigeon, jay, and black coot) from a Rasa Bay area (North Adriatic, Croatia). They have presumably been exposed to elevated Se and metal levels in garden soil, surface water, and aquatic sediment contaminated with superhigh-organic-sulphur (SHOS) Rasa coal, highly enriched in S, Se, V, and U. Results point at selenium contamination of stream water (up to 78 µg/L total Se in a non-filtered sample), which is well above the Croatian regulatory threshold of 10 µg/L total Se. The stream drains a site of the former coal-separation unit, and an associated bottom sediment contains up to 10.8 mg/kg total Se, which is also above the safe level of 0.60 mg/kg total Se. Moreover, values of Mo, U, V, and Sr, elements commonly elevated in SHOS coal varieties, were also increased in majority of water samples as well as in analysed vegetables, soil, and aquatic sediments. Although Cu, Zn, Pb, and V were slightly increased in liver samples of birds, more in black coot than the other two birds, selenium values were found to be adequate for their normal growth. The fact that Se can be environmentally hazardous and toxic to life, even in small doses, warrants further research on this topic.

Hydrogeochemistry and Groundwater Quality Evaluation in a Part of Ratnagiri District Maharashtra

In the present work attempt has been made to determine the groundwater quality in four talukas of Ratnagiri district: Chiplun, Khed, Guhagar and Dapoli. Total 60 groundwater samples were collected from borewells and handpumps in premonsoon and postmonsoon season. The groundwater samples were analyzed for pH, EC, TDS, Ca, Na, Mg, K, HCO3, Cl, SO4, NO3, Fe and F to comprehend the hydrogeochemistry of the study area. The spatio temporal variation of the major cations and anions has been shown in interpolation maps. The groundwater has concentration of iron above permissible limit in the industrial area of LoteParshuram. Piper trilinear diagram has been plotted to understand the hydrochemical facies that showed that water is mainly Ca-Cl-HCO3 type. Durov diagram was used to know the hydrogeochemical nature of the groundwater. The scatter plot diagram of concentration of calcium and magnesium against bicarbonate and sulfate of groundwater indicates that silicate weathering is dominating the area. Chloro Alkaline Indices showed that there is direct exchange of ions in most of the samples. Trends in mineral saturation indices have been studied by the PHREEQC. The groundwater showed oversaturation of iron. Water quality index based on WHO parameters has been calculated which showed that majority of water samples are recommended for drinking purpose except few samples which have very high iron concentration. The suitability of groundwater for the purpose of Irrigation has been determined by evaluating parameters Sodium adsorption ratio (SAR), sodium percent (% Na), Residual Sodium Carbonate (RSC), Magnesium Ratio, Kelley Ratio and Permeability Index. The results showed that most of the groundwater samples are suitable for irrigation.

Detection rates of waterborne protozoa in water sources from Fayoum Governorate

Background: Waterborne protozoal infections are common health problems in many parts of the world especially in developing countries. Water is a major vehicle for transmission of protozoa such as G. lamblia, Cryptosporidium spp. as well as pathogenic and opportunistic free living amoeba (FLA).Objective: This study aims to detect the presence of protozoal agents in tap water and storage water tanks at Fayoum Governorate, Egypt.Material and Methods: A total of ninety five water samples were collected from different water sources, taps (65) and tanks (30), from 6 Fayoum districts. The samples were processed to detect the presence of G. lamblia cysts by Lugol’s iodine stain, Cryptosporidium oocysts by modified Ziehl-Neelsen stain and FLA by cultivation. After cultivation, Acanthamoeba spp. were identified according to their morphological features and flagellation test was performed to detect amoeboflagellates.Results: All water samples collected from tanks (100%) were contaminated by protozoa of medical importance, while only 6 (9.2%) of the tap water samples were pathogen free. The majority of water samples were contaminated with mixed protozoal infections. The overall detection rates of contaminants in water sources were 86.3%, 52.6%, 13.7% by FLA, Cryptosporidium spp. and G. lamblia, respectively.Conclusions: The recorded detection rates of waterborne protozoa present a hazard to the community resulting in silent morbidities and mortalities. It is strongly recommended to adopt proper water safety measures.

Importance of Rocks and Their Weathering Products on Groundwater Quality in Central-East Cameroon

The present work highlights the influence of lithology on water quality in Méiganga and its surroundings. The main geological formations in this region include gneiss, granite and amphibolite. The soils developed on these rocks are of ABC type, which are acidic to slightly acidic. Electrical conductivity (EC), organic matter, total nitrogen, nitrate-nitrogen, sulfate, chloride, phosphorus and exchangeable base values were low to very low in the soil samples. Groundwater samples were investigated for their physicochemical characteristics. The wide ranges of EC values (15.1–436 µS/cm) and total dissolved solids (9–249 mg/L) revealed the heterogeneous distribution of hydrochemical processes within the groundwater of the area. The relative abundance of major dissolved species (mg/L) was Ca2+ > Na+ > Mg2+ > K+ for cations and HCO3− >> NO3− > Cl− > SO42− for anions. All the groundwater samples were soft, with total hardness values (2.54–136.65 mg/L) below the maximum permissible limits of the World Health Organization (WHO) guideline. The majority of water samples (67%) were classified as mixed CaMg-HCO3 type. Alkaline earth metal contents dominated those of alkali metals in 66.66% of samples. Thus, for the studied groundwater, Mg2+ and Ca2+ ion adsorption by clay minerals was almost nonexistent; this implies their release into the solution, which accounts for their high concentrations compared to alkali metals. Ion geochemistry revealed that water-rock interactions (silicate weathering) and ion exchange processes regulated the groundwater chemistry. One water sample points towards the evaporation domain of this diagram, indicating that groundwater probably does not originate from a deeper system. Kaolinite is the most stable secondary phase in the waters in the study area, in accordance with the geochemical process of monosiallitization, which predominated in the humid tropical zone.

Geostatistical methods in evaluating spatial variability of groundwater quality in Al-Kharj Region, Saudi Arabia

The analyses of 180 groundwater samples of Al-Kharj, Saudi Arabia, recorded that most groundwaters are unsuitable for drinking uses due to high salinity; however, they can be used for irrigation with some restriction. The electric conductivity of studied groundwater ranged between 1.05 and 10.15 dS m−1 with an average of 3.0 dS m−1. Nitrate was also found in high concentration in some groundwater. Piper diagrams revealed that the majority of water samples are magnesium–calcium/sulfate–chloride water type. The Gibbs’s diagram revealed that the chemical weathering of rock-forming minerals and evaporation are influencing the groundwater chemistry. A kriging method was used for predicting spatial distribution of salinity (EC dS m−1) and NO3− (mg L−1) in Al-Kharj’s groundwater using data of 180 different locations. After normalization of data, variogram was drawn, for selecting suitable model for fitness on experimental variogram, less residual sum of squares value was used. Then cross-validation and root mean square error were used to select the best method for interpolation. The kriging method was found suitable methods for groundwater interpolation and management using either GS+ or ArcGIS.

Water-Rock Interactions in the Bauru Aquifer System – São Paulo State, Brazil

The study focuses on the assessment of mineral saturation indexes using data of physicochemical analysis of groundwater samples from different units of the Bauru Aquifer System, in the State of São Paulo, Brazil. The analysis revealed that calcite (CaCO3) undersaturated waters dominate in the aquifer, but eventually groundwater reaches saturation with respect to this mineral. The majority of water samples are supersaturated with quartz, SiO2, and undersaturated with amorphous silica, SiO2(am). In the equilibrium diagrams, the samples are predominantly concentrated in the stability fields of the kaolinite and montmorillonite, which indicates that these mineral phases are the most probable sinks for Si and Al derived from weathered aluminosilicates.