Dominant Water Type Research Articles

Assessment of Shallow Wells of Public Importance in Selected Areas of Ekiti State Capital City, Ado Ekiti, Nigeria

ABSTRACTGroundwater is one of the main sources of public water supply all over the world. This study assessed hand‐dug wells of economic importance in selected areas of Ado Ekiti in relation to terrain characteristics. A total of 15 wells were randomly sampled with replicates from 5 densely populated parts of the study area. Water samples collected were processed and analyzed in the laboratory using established scientific methods. Results showed that physicochemical characteristics of the sampled groundwater compared favorably with the standard for drinking water, except for phosphate (PO43−) concentration, which was above the permissible limit of 0.1 mg/L. Moreover, while lead (Pb2+) was within the acceptable limits of 0.001 mg/L, cadmium (Cd2+) and iron (Fe2+) mean values of 0.01 and 16.723 mg/L were above the permissible limits of 0.003 and 0.03 mg/L, respectively. All the samples analyzed were found to contain total coliforms. Piper diagram indicates prevalence of chloride anion facies and a small portion of sulfate with no carbonate ions. There was no dominant water type among the cations. The chemical makeup mainly showed the prevalence of strong acids (Cl−) and slightly alkaline earth elements (Ca2+). The Schoeller plot suggests the dominance of calcium and elevated chloride concentrations in comparison to other ions. The water quality index indicated widespread pollution in most of the sampled water, showing that the shallow wells are not suitable for drinking purposes except in Adebayo and Erifun axis as expected. The study revealed terrain's influence and unprofessional construction of wells. A holistic water safety plan is imperative in the area and thus recommended.

Assessing surface water quality in Hungary’s Danube basin using geochemical modeling, multivariate analysis, irrigation indices, and Monte Carlo simulation

Evaluation of water quality is crucial for managing surface water effectively, ensuring its suitability for human use, and sustaining the environment. In the lower Danube River basin, various methods were employed to assess surface water quality for irrigation, drinking, human health risk purposes and the main mechanism control the surface water chemistry. These methods included water quality indicators (WQIs), complex statistical analyses, geographic information systems (GIS), Monte Carlo simulation, and geochemical modeling. Physicochemical analyses of surface water samples revealed primarily Ca–Mg–HCO3− is the dominant water types. Principal component analysis (PCA), ionic ratios and piper, chloro alkaline index, Chadha, and Gibbs diagrams identified three distinct water characteristics influenced by water-rocks interaction, evaporation, ions exchange, and human activities. The geochemical modeling showed Danube River water’s strong ability to dissolve gypsum, halite, and anhydrite (SI < 0) and precipitate aragonite, dolomite, and calcite with saturation index (SI) value greater than 0 along its flow path. The irrigation water quality index (IWQI = 99.6–107.6), sodium adsorption ratio (SAR = 0.37–0.68), sodium percentage (Na% = 13.7–18.7), soluble sodium percentage (SSP = 12.5–17.5), Potential Salinity (PS = 0.73–1.6), and Residual Sodium Carbonate (RSC = − 1.27–0.58) values were used, mainly indicating acceptable quality with some limitations. Danube River water was unsuitable for drinking based on WQI value (WQI = 81–104). Oral exposure of children to specific components showed a higher hazard index (HI > 1) compared to adults, indicating a 2.1 times higher overall non-carcinogenic risk hazard index. However, Monte Carlo simulation demonstrated negligible iron, manganese, and nitrate health hazards for both age groups. These findings are valuable for water quality management decisions, contributing to long-term resource sustainability.

Toward Decontamination in Coastal Regions: Groundwater Quality, Fluoride, Nitrate, and Human Health Risk Assessments within Multi-Aquifer Al-Hassa, Saudi Arabia

Contamination in coastal regions attributed to fluoride and nitrate cannot be disregarded, given the substantial environmental and public health issues they present worldwide. For effective decontamination, it is pivotal to identify regional pollution hotspots. This comprehensive study was performed to assess the spatial as well as indexical water quality, identify contamination sources, hotspots, and evaluate associated health risks pertaining to nitrate and fluoride in the Al-Hassa region, KSA. The physicochemical results revealed a pervasive pollution of the overall groundwater. The dominant water type was Na-Cl, indicating saltwater intrusion and reverse ion exchange impact. Spatiotemporal variations in physicochemical properties suggest diverse hydrochemical mechanisms, with geogenic factors primarily influencing groundwater chemistry. The groundwater pollution index varied between 0.8426 and 4.7172, classifying samples as moderately to very highly polluted. Similarly, the synthetic pollution index (in the range of 0.5021–4.0715) revealed that none of the samples had excellent water quality, with various degrees of pollution categories. Nitrate health quotient (HQ) values indicated chronic human health risks ranging from low to severe, with infants being the most vulnerable. Household use of nitrate-rich groundwater for showering and cleaning did not pose significant health risks. Fluoride HQ decreased with age, and children faced the highest risk of fluorosis. The hazard index (HI) yielded moderate- to high-risk values. Nitrate risks were 1.21 times higher than fluoride risks, as per average HI assessment. All samples fell into the vulnerable category based on the total hazard index (THI), with 88.89% classified as very high risk. This research provides valuable insights into groundwater quality, guiding water authorities, inhabitants, and researchers in identifying safe water sources, vulnerable regions, and human populations. The results highlight the need for appropriate treatment techniques and long-term coastal groundwater management plans.

Hydrochemistry and isotope hydrology of groundwater and surface water in the Sor and Gebba watershed, southwestern Ethiopia

The Sor and Gebba watershed plays a crucial role in the water resources of the Baro-Akobo River Basin. However, various factors have had a detrimental effect on the watershed. Unplanned groundwater extraction, wetland drainage, surface water pollution, and land use changes have all intensified due to population growth, urbanization, commercial farms, industrial development, poor water resources management, and improvements in living standards. This research utilized major hydrochemical ions and environmentally stable isotopes to elucidate the interaction between groundwater and surface water in the watershed, which are reliable tracers in various hydrologic processes. During the 2020 wet season and 2022 dry season, over 25 meteoric water samples were collected from different locations for hydrochemical and isotopic analysis. The hydrochemical analysis revealed that the dominant water type is Ca–Mg–HCO3−. Among the anions, HCO3− was the most dominant, followed by NO3−, Cl−, and SO42−, and those of cations Ca2+, followed by Na+, Mg2+, and K+. The spatial analysis of environmentally stable isotopes confirmed the interaction between groundwater and surface water in the watershed. The quality of groundwater is primarily influenced by rock-water interaction (Gibb's diagram) and, to some extent, by evaporation (Isotope study). A graph of the water samples closely aligned with the Addis Ababa-local meteoric water line indicates their meteoric origin. However, there was a slight deviation to the left due to the effects of distance and altitude. The isotopic correlation further supported the interaction between different water sources.

Identifying intrusion of seawater in coastal aquifers by modified GALDIT (M-GALDIT) index

Contamination of coastal aquifers by seawater intrusion (SWI) is a major environmental problem. A modified GALDIT method (M-GALDIT), and multi-criteria decision model AHP has been used to identify regions vulnerable to seawater intrusion. We have used the groundwater suitability index for seawater intrusion (GQISWI) in estimating the M-GALDIT index. While the GALDIT analysis indicates that ∼28% of the area is moderately vulnerable, and 8% of the area is relatively highly vulnerable, our estimates using AHP and M-GALDIT method indicate ∼19% of the area as moderately vulnerable, ∼22% of the area as relatively highly vulnerable zones. The GQISWI values in the region vary between 0 and 96.96, indicating that most of the groundwater samples belong to mixed water types. Faults and fractures, population distribution, water-rock interaction, ionic exchange reactions, and evaporation appear to be the dominant mechanisms, besides seawater intrusion that control the overall groundwater geochemistry in the region. Ca2+-HCO3-, Ca2+-Na+-HCO3−, and Ca2+-Mg2+-Cl− are the most dominant water types in the study area. The seawater mixing index (SMI) reveals that ∼34.5% of samples are of relatively freshwater types, whereas ∼61% of samples appear contaminated to some extent, presumably due to the mixing of seawater, or anthropogenic activities such as mining, agricultural activities, etc. Furthermore, analysis of the HFE-D diagram indicates that ∼23% of samples are directly affected by seawater intrusion.

Assessing the quality of drinking water from selected water sources in Mbarara city, South-western Uganda.

This study assessed the physical, chemical, and microbiological quality with emphasis on risk score, source apportionment, geochemistry, feacal coliforms and water quality index of drinking water from selected water sources. A cross-sectional study was conducted in six villages in Mbarara city, south-western Uganda. Each selected source was inspected using a WHO-adopted sanitary inspection questionnaire. Each source's risk score was calculated. Thirty-seven samples were taken from one borehole, nine open dug wells, four rain harvest tanks, and twenty-three taps. The values for apparent color and phosphate were higher than the permissible level as set by the World Health Organization and Ugandan standards (US EAS 12). The isolated organisms were Klebsiella spp. (8.11%), Citrobacter divergens (62.16%), Citrobacter fluendii (2.7%), E. coli (35.14%), Enterobacter aerogenes (8.11%), Enterobacter agglomerus (5.4%), Proteus spp. (2.7%), Enterobacter cloacae (13.5%), and Proteus mirabilis (2.7%). Twelve water sources (32.4%) had water that was unfit for human consumption that was unfit for human consumption (Grade E), Five sources (13.5%) had water that had a very poor index (Grade D), nine (24.3%) had water of poor index (Grade C), eight (21.6%) had water of good water index (Grade B), and only three (8.1%) had water of excellent water quality index (Grade A). The piper trilinear revealed that the dominant water type of the area were Mgso4 and Caso4 type. Gibbs plot represents precipitation dominance. PCA for source apportionment showed that well, tap and borehole water account for the highest variations in the quality of drinking water. These results suggest that drinking water from sources in Mbarara city is not suitable for direct human consumption without treatment. We recommend necessary improvements in water treatment, distribution, and maintenance of all the available water sources in Mbarara City, South Western Uganda.

Hydrogeochemical characterization of groundwater in mountainous catchment and its suitability for drinking purposes in Irob, Tigray, Northern Ethiopia

Abstract The primary source of drinking water in Ethiopia's semi-arid mountainous regions is groundwater. The present study aims to assess the hydrogeochemical characteristics of low-grade basement rocks dominated by mountainous catchments. Moreover, it examines the suitability of the groundwater quality for drinking purposes in Irob, Tigray, northern Ethiopia. However, relatively little is known about the water chemistry and groundwater quality of the resources in the area. Fifteen samples of groundwater were collected and examined for ions according to standard procedures. The outcomes were assessed against the World Health Organization (WHO) drinking water quality criteria. To identify the source of dissolved ions and the process involved, graphic interpretations were applied. The results show that Ca–Mg–SO4–HCO3 and Ca–SO4–HCO3 were the dominant water types. Gibbs plots and ionic ratios reveal that silicate weathering, carbonate dissolution and ion exchange control water chemistry. Furthermore, the findings reveal that 60, 80, 46.67, 46.67, 60, 6.67, 60 and 53.33% of samples are above the safe limits of the WHO for hardness, alkalinity, total dissolved solids, electrical conductivity, calcium (Ca2+), potassium (K+), bicarbonate (HCO3-) and sulfate (SO42-), respectively. Consequently, the groundwater quality assessment demonstrates that the water sources in lower parts of the catchment are unsuitable for drinking.

Assessing wet season water quality and health risks of Chaobai River: impacts of natural weathering and anthropogenic activities in a small urban watershed

ABSTRACT Small urban watersheds are susceptible to external influences, facing increased solute inputs during high-flow periods without sufficient dilution. This study determined the sources of major ions in the Chaobai River, which is the essential surface water source of North China. The dominant river water type was HCO3-Ca·Mg based on the Piper diagram. PCA and ion ratios revealed that natural weathering (evaporate dissolution, carbonate, and silicate weathering by carbonic and sulfuric acid) and anthropogenic activities (urban domestic sewage and industrial effluent) were the dominant factors affecting the chemical composition. Sodium adsorption ratio (SAR), soluble sodium percentage (Na%), and residual sodium carbonate (RSC) assessments indicated potential sodium and moderate salinity hazards. Meanwhile, the non-carcinogenic health risks of riverine solutes evaluated by health risk assessment need to be noticed, particularly for children. The limitation of urban sewage discharge is crucial for improving water quality in urban watershed and needs further studies.

Evaluation of Geology and Hydrochemistry of Nawfia-Agulu Axis of Anambra State, Southeastern Nigeria

The investigation of the geological, hydrochemical, and engineering characteristics of the Nawfia – Agulu area was carried out. The study aimed at mapping the geology through field data collection, outcrop logging, and laboratory analysis. Consequently, eleven soil and ten water samples were collected and analyzed through particle size distribution test; Atterberg limits tests and hydrochemical analysis to provide insights into the lithology, sediment characteristics, and water quality. The results indicated the dominance of the Ameki/Nanka Formation and Imo Formation as the underlying geology of the study area. The grain sizes of the sand samples ranged from medium to coarse grained, moderately to poorly sorted, and strongly positive to positively-skewed. The depositional environment was nearshore/beach, influenced by nearshore waves and turbulent currents. Engineering properties highlighted the prevalence of uniformly to well-graded soil and moderately to highly plastic behavior, as indicated by the mean plasticity index (PI) value of 26%. These findings suggest potential challenges for infrastructural development in some parts of the area. The water quality indicated slightly acidic water. The physical parameters and the major ions were within the permissible limits of World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). However, elevated concentrations of heavy metals, including lead, chromium, mercury, iron, and cadmium, in water sources exceeded the respective permissible limits for drinking water indicating contamination/pollution. The dominant water type was Ca2+ – Mg2+– SO42- – Cl– and the dominant hydrochemical process was simple dissolution or mixing and ion-exchange.

Evaluating groundwater quality using health risk assessment and irrigation indexes: Saveh Aquifer, Iran

Abstract The aim of the study was to assess water quality in the Saveh aquifer for drinking, public health, and agricultural uses. The heavy metal pollution index (HPI), hazard index (HI) using non-carcinogenic health risk assessment, sodium percentage, sodium adsorption ratio (SAR), irrigation water quality index (IWQI), and a Piper diagram were used. The HPI exceeded 3,300, much higher than the WHO critical value, which is 100. The aquifer is severely contaminated with heavy metals and unsuitable for drinking. The heavy metal concentrations also caused the water to have cumulative HI &amp;gt; 1 in 54 and 77% of sampling wells, respectively, for adults and children. For agriculture, both %NA and IWQI were stricter than SAR. Most of the aquifer was deemed suitable for irrigation using SAR, while %Na showed most parts unreliable, and IWQI represented almost all areas unsuitable for irrigation. The Piper diagram showed that the dominant water type was N–Cl, followed by Na–HCO3 and Ca–HCO3, indicating high aquifer salinity. Generally, the Saveh aquifer is saline and heavily polluted with heavy metals, so its use for drinking and/or irrigation carries many risks.

Reflecting on changes in the drinking and irrigation water quality of rivers Beas, Satluj and confluence waters.

Prevention and control of water pollution for maintaining and restoring the wholesomeness of rivers are unavoidable. The current water quality approach of designated best use has some limitations such as it is non-integrative and inflexible with regard to the consideration of variables and does not provide a separate rating scale for a given designated use. We thus used water quality index approach proposed by the Canadian Council of Ministers of the Environment (CCME WQI) to evaluate and develop a separate rating system for drinking and irrigation purposes of rivers Beas, Satluj and their confluence water of the Indian Punjab using information collected over 4 years (2016 to 2019). River Beas exhibited better water quality compared to river Satluj for irrigation as well as for drinking. The overall drinking water quality index (DWQI) for Beas was marginal (45.5), whereas it was poor for Satluj (37.7) and confluence waters (40.1). The spatial variation in DWQI was greater for Satluj compared to Beas and confluence waters reflecting the effect of dumping of untreated industrial and domestic waste waters. Variables such as Total coliform (T. coli), dissolved oxygen (DO), turbidity and biological oxygen demand (BOD) contributed to the deterioration of DWQI. The irrigation water quality index (IWQI) was good for Beas (86), marginal for Satluj (60.1) and fair for confluence waters (71.2). Faecal coliform (F. coli), Kelly ratio (KR) and %Na contributed to the deterioration of IWQI. Calcium-magnesium-bicarbonate (Ca-Mg-HCO3) was the dominant water type in Beas and confluence waters, whereas for Satluj, in addition to Ca-Mg-HCO3, sodium-potassium-chloride-sulphate and mixed water types were also prevalent. The river waters witnessed salinity hazard but did not pose sodicity hazard except at a few locations of Satluj. The study indicates the need to take location specific measures for improving river water quality for drinking as well as irrigation purposes. The current status of water quality calls for an urgent need to formulate stringent policy regulations to maintain the surface water quality.

Groundwater characterization including prediction of the quality, fluoride, and nitrate occurrence in a typical artisanal mining area in Ghana: A hydrochemical and multivariate statistical approach

Groundwater quality has been compromised by both geogenic and anthropogenic activities. Also, the negative impact of the intake of groundwater with high fluoride and nitrate content has been well established. Artisanal gold mining operations within the Tinga-Maluwe areas go beyond a decade with no knowledge of the level of impact these activities have on the groundwater quality. Hence, this study aims to characterize the groundwater with emphasis on the quality for usage as well as the controls of fluoride and nitrate occurrence in the area using hydrochemistry and multivariate linear regression modeling techniques. This is to enhance groundwater monitoring and stakeholder decision-making processes in the catchment. The concentration order of the cations is Ca2+ > Na+ > Mg2+ > K+ and that of the anions is HCO3− > NO3− > Cl− > SO42− > CO32− > F− with a Na – Cl dominant water type. Apart from F−, NO3−, and TDS exceeding their acceptable limits in Tinga, the overall pollution, water quality, and percentage of pollution indices show that the groundwater is slightly to heavily polluted in Daklupe, Seripe, Tinga, Kablima, Maluwe, Sakpa, and Bekwa-kura communities. Mineral dissolution, especially carbonate minerals, is the dominant process controlling groundwater mineralization from the discriminant diagrams used, and the saturation indices. However, anthropogenic activities impact on the groundwater cannot be precluded from the MLRMs of OPI, WQI, and PPI. The MLRMs show that pH, SO42−, Na+, K+, Ca2+, and Mg2+ are the controls of F− occurrence while that of NO3− is by TDS and pH.

Water Quality Parameters Evaluation of Sipna Stream, Duhok area, Kurdistan Region-Iraq

Due to the security situation surrounding the Sipna area, there has been a rapid migration of the population to the Sipna area over the past fifteen years, which has increased agricultural activities as well as some small and medium factories. This has necessitated the evaluation of the water quality and its appropriateness for various uses in the Sipna area. The Sipna stream, which is part of the Greater Zab River, is located in the Sheladize area, 60 km to the northeast of Duhok City in the Iraqi Kurdistan Region. Between the low-flow season (12-October/2021) and the high-flow season (18-April/2022), forty surface water samples were taken by polyethylene bottle from both seasons. The study aims to assess the quality of surface water and the extent of the impact of human activities on the Sipna stream and the possibility of using it as a database for comparison in the future. The findings indicate that Ca-bicarbonate and TDS values range from 219-606 ppm with an average of 321 ppm for the dry season and 188-685 ppm with an average of 251 ppm for the wet season, it is the dominant water type in the study area. According to to mean values, the main ion concentrations for cations were Ca2+&gt; Mg2+&gt; Na+&gt; K+, and HCO3-&gt; SO42-&gt; Cl-&gt; NO3- anions. The most prevalent hydrochemical natural processes are rock weathering and its mainly responsible for the water quality in the study area. Water indices and comparisons to the WHO standard revealed that the Sipna stream's quality is suitable for use as drinking water and a wide range of other purposes.

Wastewater irrigation and its impact on crops in major cultivated belt of Rechna Doab, Pakistan

The purpose of this study was to evaluate the toxicity of wastewater that is used for irrigation in study area. This research focused on the wastewater irrigation in suburban areas of Faisalabad district. The study involved collection of wastewater samples from ten different locations from Faisalabad, Jaranwala and Saddar districts to assess its quality at different sites. Areas covered by wastewater irrigation ranged from 100 to 2000 acres and major crops were cultivated using this contaminated water, including wheat, cauliflower, radish, spinach, and fenugreek. Physiochemical characteristics of wastewater, including the presence of heavy metals, were measured. The ionic compositions and heavy metal toxicity of wastewater was determined to fall at poisonous levels. Physiochemical properties and quality indices used in the current study also depict the unsuitable nature of the wastewater used in the area. The sources of wastewater varied from drains, sewage water, and the Chakkera Disposal system. Maps generated in Arc Map 10.5 show the spatial distribution of constituents via the geostatistical IDW (Inverse Distance Weighted) technique. The Piper and Durov diagrams highlighted the wastewater chemistry and showed that the dominant water type obtained was NaCl. Results were statistically analyzed by a correlation matrix. Dominant ions, pH levels, electric conductivity (EC), and heavy metals were detected by lab analysis and results indicated variability in toxic levels of these properties within the site and the area using the wastewater irrigation system. Consequently, this indicated the unsuitable nature of using wastewater as an irrigation source. The study concludes that it is necessary to conduct proper treatments to irrigation water before it is used on crops.

Hydrochemistry, water quality and health risk assessment of streams in Bismil plain, an important agricultural area in southeast Türkiye

In this study, the water quality of Ambar, Kuruçay, Pamuk and Salat streams, which are the important tributaries of the Tigris River in the Bismil Plain (Diyarbakır, Türkiye) was assessed using 19 physicochemical parameters. Except for a few exceptions, all parameters in the water samples taken from the streams were below the drinking water limit values. Kuruçay Stream had significantly higher TOC, Na+, NO3−, NO2−, Cl− and SO42− levels and lower DO levels than other streams (p < 0.05) due to sewage water discharges, animal manure storage areas near the stream and irrigation return flows. In all streams, Ca–HCO3 was dominant water type. Gibbs diagram indicated that rock weathering is the major factor controlling the hydrochemistry of the streams. According to the results of water quality index (WQI), all sampling stations of Ambar, Pamuk and Salat streams and K1 station of Kuruçay Stream had “good” quality water for drinking purposes, while K2 station of Kuruçay Stream had “poor” quality water. Irrigation indices (permeability index, sodium percentage, magnesium hazard, residual sodium carbonate, Kelley's ratio, sodium adsorption ratio and potential salinity) revealed that all water samples taken from the streams were suitable for irrigation. The water samples from Ambar, Pamuk and Salat streams were in the C2S1 (medium salinity and low alkalinity) category, while the samples from Kuruçay Stream were in the C2S1 and C3S1 (high salinity and low alkalinity) categories. Both hazard quotient and hazard index values of NO3–N, NO2–N and F− for children and adults were found below 1, indicating that adverse health effects are not expected from exposure to these contaminants via water ingestion and dermal contact. The findings of this study showed that the water quality status of Kuruçay Stream is worse as it receives large amounts of irrigation return flows compared to other streams.

δ18O and δ2H isotopes, trace metals and major ions in groundwater around uranium and fluoride contaminated Indus valley Quaternary alluvial plain, SW Punjab, India: Implications on hydrogeochemical processes, irrigation use and source

Uranium and fluoride enrichment in groundwater along alluvial plains pose a severe threat to living beings like cancer, fluorosis and crop yield as witnessed around semi-arid southwest Punjab, India. In-situ groundwater was examined for major ions, stable isotopes and trace metals to understand the hydrogeochemical processes, contaminant origin and health risks around SW Punjab, India. Groundwater from a freshly drilled bore well is found to be hard, alkaline, and saline with total dissolved solids and salinity up to 1300 and 1500 mg L−1, respectively. Fluoride (up to 4 mg L−1) and uranium (up to 90.07 μg L−1) contents exceed permissible limits in most samples and originated from fertilizer inputs and aquifer leaching. Uranium contents decline with depth, while fluoride remains invariable. Decreased U contents are inferred to be caused by U(VI) reduction to U(IV) as evidenced by an increase in Fe2+ vs. Fe3+, S2− vs. S6+ and N3− vs. N5+ with depth. NaHCO3, NaCl + NaHCO3 and NaCl are the dominant water types for shallow (<38 m), intermediate (49–83 m) and deeper groundwater (105–128 m) with Na+ and HCO3− as the dominant cations and anions, respectively. Silicate weathering majorly controlled the groundwater geochemistry together with a partial contribution from cation exchange processes. Unsuitability for drinking and irrigation use is envisaged for all depths, while deeper groundwater is safe in regard to radiological risk. δ18O and δD variations are suggestive of evaporation dominance in shallow groundwater, while intermediate groundwater witness canal and groundwater mixing and deeper groundwater are recharged through higher altitude.

Environmental isotope constraints and hydrogeochemical evolution of groundwater in the semi-arid national capital environs of Delhi, India

Changes in hydrological regimes due to rapid urbanization and increasing anthropogenic stress on hydro-geological system creating an alarming condition for the management of ground water resources. Isotope and hydro-geochemical integrated approach has been used to determine the processes governing chemical composition of groundwater and the mechanism influencing the chemical composition of groundwater in National Capital Region (NCR), Delhi. The chemical evolution of groundwater has studied by using flow direction, hydro-chemical facies, bivariate plots of ionic ratios and saturation index. Stable isotopes and tritium are used to understand the recharge mechanism. Pollution index of groundwater (PIG) is also used to check the level of contamination in the groundwater. In total, 57 water samples were collected for water chemistry, 36 water samples for environmental isotopes and 13 samples for tritium measurement. The dominant water type is Ca-Mg-HCO3 and mixed water type. The dominant cation are Ca2+ > Na+ > Mg2+ > K+ and dominant anions are HCO3− > Cl− > SO42− > NO3−. The bicarbonate type water is dominant in quartzite, implies rapid and direct recharge through fracture and joints. Ionic ratios and saturation indices show that major processes controlling groundwater evolution are silicate hydrolysis and reverse cation exchange in the quartzite. Average values of δ2H and δ18O are −43.66 ‰ and −6.28‰. Stable isotopic ratio of groundwater of alluvium area falling on evaporation line, due to the prevailing semi-arid and arid climatic conditions, evaporation is the predominant factor affecting the chemistry of groundwater. The stable isotope shows that the groundwater in the quartzite is mostly meteoric in origin and acting as a recharge area for the nearby alluvium aquifer. Tritium results reveal that groundwater occurring in quartzite and alluvium aquifer in western parts are older than that of groundwater occurring in alluvium aquifer in the eastern parts.13% of groundwater samples are falling in very high pollution zone mainly occurring in alluvium aquifer that lies in the Eastern parts. It is inferred that alluvium aquifer (low lying) is having greater impact of anthropogenic activity than quartzite aquifer (high land).

Hydrogeochemical characterization of groundwater in a coastal area, central western Senegal

One of the most serious problems affecting coastal aquifers is seawater intrusion. Senegal is currently facing an increased demand for freshwater resources due to population growth and economic development in coastal areas. In areas affected by saltwater contamination, chloride concentrations as high as 8880 mg/L were measured in groundwater samples taken from wells near the coastal zone, indicating deterioration in water quality. Our study aims to identify the zones of degradation of the water quality by determining the chemical composition of groundwater and the geochemical processes controlling the chemical patterns. Hydrogeochemical (Piper and Chadha diagrams, chloroalkaline indices, normalized bivariate plots) and multivariate statistical (Hierarchical cluster analyses) techniques were used. Forty-two groundwater samples were collected and analyzed for concentrations of major and some minor ions, electrical conductivity (EC), total dissolved solids (TDS), temperature, and pH. From samples we were able to establish a diagnosis of the very heterogeneous quality of the groundwater in this area. The average pH of the groundwater is 7.6 and about 80% of the groundwater samples have a TDS below 1000 mg/L. On the other hand, the EC values are very heterogeneous with very high conductivities in coastal areas. Approximately, 80% of the groundwater samples have a TDS less than 1000 mg/L and EC values are very heterogeneous. The dominant water types in the study area are Na-Cl water type (less than 10% of the samples) characteristic of the spatial evolution of groundwater salinization from west to east, mixed Ca-Mg-Cl due to fresh water/salt water contact and Ca-Mg-HCO3 water-type (nearly 56% of the samples) to the east. A hydrogeochemical zonation of the aquifer, based on the presence of different water families allows us to visualize the highly degraded (west), mixed (center) and healthy (east) zones. Chloroalkaline indices and normalized bivariate plots show that the chemistry of groundwater is controlled mainly by water-rock interaction and evaporation processes. As water-rock interaction processes, dissolution of carbonate and evaporite, weathering of silicate, ions exchange regulates major ion chemistry.

Arsenic in groundwater from Southwest Bangladesh: Sources, water quality, and potential health concern

Arsenic (As) poisoning in groundwater has become one of the greatest environmental concerns around the world. In this study, As concentration in the groundwater samples (depth: 52–70 m) of southwestern Bangladesh was evaluated using Atomic Absorption Spectrometer (AAS) to know the current status, possible source(s), and probable health risk of As. In addition, the other relevant water quality parameters (pH, temperature, EC, TDS, Na+, K+, Ca2+, Mg2+, Cl−, NO3−, SO42−, HCO3−, Fe, and Mn) were also measured using various instruments such as portable bench meter, Flame photometer, AAS, and Ion Chromatograph to evaluate the suitability of the water for drinking and irrigation purposes. Arsenic concentration (μg L−1) ranged from 13.10 to 292 (mean ± SD: 156.9 ± 100.31), which is alarmingly, and 15 times higher than the WHO recommended value for drinking water. pH values of collected groundwater samples ranged from 7.17 to 8.09, which exhibits a lightly alkaline nature. The average abundance of major cation follows the order of Ca2+ > Mg2+ > Na+ > K+, and the average abundance of major anions follows the order of HCO3− > Cl− > NO3− > SO42−, with Ca2+and HCO3− being the dominant cation and anion, respectively. Based on water quality assessments utilizing the water quality index and entropy water quality index, the groundwater in the region of interest was not suitable for drinking or irrigation purposes. The Piper tri-linear diagram suggests the dominant water type in the study area was the Ca-HCO3 type, where Ca and HCO3− are the principal cations and anions, respectively. A bivariate analysis of different hydro-chemical parameters revealed that silicate weathering controls the hydrogeochemical processes in groundwater. Principal component and hierarchical cluster analysis indicate As in groundwater are geogenic in origin under reductive dissolution processes. The moderate correlation between As, Fe, and Mn indicate reductive dissolution of FeOOH and MnOOH plays a vital role in releasing As from sediment to groundwater. Probable cancer risk assessment for both adults and children revealed a higher value than the recommended value of 10−6 according to United Nations Environmental Protection Agency (USEPA), suggesting that people in the area of interest were at high carcinogenic risk.

The Geodiversity of Springs in the Potential Jericho Geopark/Palestine

The objective of this study is to investigate the hydrogeological and hydrochemical characteristics of the spring aquifer system in the potential Jericho Geopark in Jericho, Palestine. The spring’s hydrochemistry influences the physical and hydrochemical characteristics of Jericho Geopark in qualitative potentials. The springs are used for domestic water supplies and irrigation in Jericho area, which is considered as one of the most important agricultural baskets of the West Bank feeding from the “spring system complex”. From the geological and structural point of view, the area is considered to be complex in relation to the major structural features of faults and folds, which formed during the formation of the Jordan Rift Valley. The physical properties (pH, DO, temperature, TDS and EC) were interpreted. The hydro-chemical concentration major ions of Ca2+, Mg2+, Na+, K+, Cl−, SO42−, NO3− and HCO3− were analyzed for the spring water system samples. The dominant spring water type is the calcium bicarbonate due to the dissociation of calcite mineral during the water rock interaction processes. The microbiological parameters of Total and Fecal coliforms were analyzed for the targeted springs and indicates no detected pollution. The hydrochemical characteristics of the spring waters indicate no ion concentration trends. The calculated quality water Index indicated that all springs are of excellent spring water type. The study contributes to the qualitative spring water as a major component to the potential Jericho Geopark in order to have better understanding of the community-based protection practice.