Base Exchange Index Research Articles

Assessment of groundwater quality and suitability for irrigation purpose using irrigation indices, remote sensing and GIS approach

Assessing both the quantitative and qualitative aspects of groundwater is essential for evaluating its suitability for irrigation and drinking purpose. Consequently, this current study showcases its importance by determining groundwater quality in Sundargarh district of, India, where groundwater serves as vital water resources. 360 groundwater samples were collected from various dug wells during pre-monsoon season of 2014–21 and analyzed for major ions, some important irrigation water quality indices along with pH, EC and TDS. Statistical evaluation of groundwater quality parameters was performed by physiochemical analysis with association of ArcGIS 10.4 for developing the spatial mapping. Furthermore, statistical and hydrochemical analysis was executed by exhibiting box plot generation, correlation study and hierarchical cluster analysis followed by categorization of water facies in , 1920; CGWB, 2013; Gad and Hattab, 2019’ has/have not been found in the reference list. Please add the corresponding reference(s) to the reference list.>Xlstat 2023, SPSS 23 and Diagrammes 6.1. Groundwater is mostly characterized as Na+-SO42- and deep meteoric percolation (DMP) type based on Base Exchange Indices with the dominance of Ca2+ and HCO3− as the major cation and anion respectively. Besides that, groundwater from 92%, 96%, 84%, 100%, 99%, 98%, 57%, 64%, 100%, 77%, 98% and 89% dug wells are found to be highly suitable for cultivation of major crops of this district depending on spatial variation of EC, TDS. Cl−, SAR, RSC, KR, PI, %Na, ESP, MAR, SSP and PS respectively. Groundwater facies are mostly categorized as Ca–HCO3 (60.8%) and C2–S1 (65.5%) type based on Piper and Wilcox diagram respectively. The dominant geochemical controlling factors are evaporation, reverse ion exchange and silicate weathering. Therefore, the objectives of this present research may provide necessary information to the regulatory boards and policy makers for efficient monitoring of groundwater quality and contaminated aquifers in Sundargarh district to make fit this crucial water resources for agricultural purpose.

The influence of lithology and climatic conditions on the groundwater quality in the semi-arid-regions: case study of the Eastern Middle Cheliff alluvial aquifer (northwestern Algeria)

Over the last few years, the Eastern Middle Cheliff plain has witnessed remarkable economic growth, particularly in the agricultural sector. However, the overexploitation of the alluvial aquifer, coupled with agricultural practices involving the use of fertilizers and pesticides, significantly contributed to the degradation of groundwater quality. The primary objective of this study is to comprehend the mechanisms governing the water chemistry of the Eastern Middle Cheliff alluvial aquifer. A total of 42 samples were collected and analyzed during the dry periods of the 2012 and 2017. The data processing and representation involved the utilization of analytical tools including Principal Component Analysis (PCA), Piper diagram, Stabler classification, binary diagrams, base exchange indices, saturation indices, and geostatistical methods. The interpretation of these data revealed the following findings: i) the groundwater in both the dry periods of 2012 and 2017 is characterized by the presence of two dominant hydro-chemical facies, namely calcium chloride and sodium chloride, as indicated by the Piper and Stabler diagrams; ii) the hydrochemical quality of the groundwater varies across different regions of the aquifer, fair to poor in the eastern and central regions, with the presence of certain contaminants resulting from the application of nitrates in agricultural activities. The quality is classified as very poor in the western region, primarily due to high salinity influenced by the lithology of the aquifer, the rise of deep salty water through the Cheliff fault due to the earthquake of the year 1980 and possibility by two climatic factors, namely evaporation and rainfall. Overall, this study provides new insights into the water chemistry dynamics of the Eastern Middle Cheliff alluvial aquifer, highlighting the varying hydrochemical facies and the impact of agricultural activities and climatic factors on groundwater quality in different areas of the aquifer.

Tracing Saltwater Intrusion into Shallow Mangrove Aquifers Using Hydrogeochemical Analysis and Isotopes of Oxygen and Hydrogen

AbstractCoastal aquifers that are hydraulically connected to the ocean suffer from the compromised of the wholesomeness of freshwater. The extent of the effect is largely dependent on the degree of aquifer stressing. Consequently, ratios of the stable isotopes of hydrogen (δ2H) and oxygen (δ18O) are integrated with ionic ratios of groundwater samples to assess the effect of intrusion on shallow aquifers in a low‐lying area of the western Niger Delta basin. Geochemical analysis shows sodium chloride (NaCl) water type, an indication that intrusion has a noteworthy effect on concentrations of groundwater by having values of total dissolved solids, electrical conductivity, and Cl− in excess of 1000, 500, and 250 mg L−1, respectively. Major ionic ratios of Na+/Cl− (0.06–1.76), Ca2+/Mg2+ (0.48–0.98), Cl−/HCO3− (148.77– 88), Cl−/HCO3− + SO42− (>1), and base exchange index (14.03 to 1.26) are largely indicative of intrusion. The δ18O and δ2H composition of groundwater and the brackish Forcados River samples reveal values that range from −4.2‰ to 1.08‰ and 0.18‰ to 3.8‰, respectively. The shallow groundwater samples are more depleted than the deep aquifers with δ18O values of −4.2‰ to −3.8‰ and δ2H of −20.99‰ to 18.51‰, respectively. The Cl−/δ18O ratios show the mixing of shallow aquifers with saltwater (SW) from the ocean.

Hydrochemical assessment of groundwater quality in the Narmada River Basin (Central India)

Abstract This study details the hydrochemical characterization and human health risk assessment of groundwater in the Narmada River Basin. The study was performed based on data collected from 305 groundwater sample stations in the Narmada River Basin. Hydrochemical evaluation illustrated that cationic ions in the upper and middle Narmada Basin were dominated by Ca2+; however, in the lower basin it was dominated by Na+ ions. Similarly, anionic ions were dominated by HCO3− throughout the basin. A Chadha plot drawn from the collected data inferred that most groundwater belonged to the recharge water category (Ca-Mg-HCO3 type). Base-exchange indices of the collected data confirmed the presence of Na+-SO42− type of groundwater. Meteoric genesis indices indicated deep meteoric percolation groundwater. Further, Gibbs plots categorized groundwater samples in the rock dominated section, while chloro-alkaline indices confirmed direct as well as reverse ion-exchange reactions governing groundwater quality. Water Quality Index values showed that groundwater ranged from excellent to very poor. Human health risk of the Narmada River confirmed the non-carcinogenic risk for Nitrate (NO3−) and Fluoride (F−) ions. However, several indices justified that groundwater was ideal for irrigation. However, groundwater treatment is recommended before direct consumption such as drinking.

Assessment of Groundwater Quality by Using the Ionic Ratios in the Coastal Region of Guntur District, Andhra Pradesh, India

Seawater intrusion into the coastal region has occurred all around the world as a result of extensive groundwater depletion brought on by population development, agricultural practices, and rapid urbanization. As a result the natural balance has been altered, and the salinization process has accelerated due to its continued stress on the world's water and land resources. One such area currently susceptible to salinization is the coastal region of the Guntur district, particularly when seawater intrusion occurs. Demand for freshwater is rising in coastal areas, which makes this issue worse. The current study makes an effort to examine the water quality parameters and to discover the contamination groundwater with saline water intrusion into the coastal mandals of Guntur district. Sampling and analysis of the samples of the study region for physcio-chemical properties of the major ions used to identify saltwater intrusion in groundwater. Ionic ratios of different kinds, including Na+/Cl−, Mg2+/Ca2+, Mg/Cl−, SO42−/Cl−, K+/Cl−, Ca2+/(HCO3+SO42-), Cl−/( HCO3−+ CO3−), Cl-/HCO3- and the Base Exchange Index (BEX) was used to determine whether or not saltwater had an impact on groundwater quality. The results of the analysis indicating that intrusion of seawater has caused salinization in the majority of the studied region and also showing higher levels of chloride, bicarbonate and sodium concentrations. By the overall observation of results it is known that contamination of the area caused by intrusion of seawater.

Assessment of Groundwater Quality for Drinking and Irrigation Use in Gurugram Block of Gurugram District, Haryana, India

Groundwater is a vital and reliable source of water in all climates worldwide. In this work, a total of 26 groundwater samples were collected from the Gurugram Block of Gurugram District (a cosmopolitan city situtated proximately to capital of India) analyzed for electrical conductivity, pH, hardness, dissolved solids (TDS), Na+, K+, Ca2+, Mg2+, Cl- and alkalinity as HCO3 −, CO3 2−. Based on the analytical results, the sodium adsorption ratio, sodium percentage, residual sodium carbonate, chloro-alkaline index, base exchange index, meteoric genesis index, permeability index), magnesium hazard and Kelly index were calculated. The most abundant cations were Na+ and Ca2+, which accounted for 43% and 36% of total cations, respectively. Based on median value, the cations are in the following order: Na+ > Ca2+ > Mg2+ > K+. There are no dangers in any of the 22 villages (85%). They have fluoride levels which are less than the maximum desirable limit of 1.0 mg/L established by IS: 10500, 2012. There were 15 villages (58%) with nitrate concentrations less than the limit (45 mg/L) and 11 villages (42%) with nitrate concentrations greater than the limit. The conductivity of groundwater samples was dominated by the ions EC-TDS (r = 1.0), EC-Na (r = 0.93) and EC-HCO3 (r = 0.84). The natural origin of the ions was revealed by the Na-Cl correlation coefficient (r = 0.82). TDS and Na correlated positively (r = 0.93). Wilcox classified that 4% of the ground water samples as excellent to good, 19% as good to permissible, more than 19% as doubtful to unsuitable and 58% as unsuitable for irrigation. According to the US salinity diagram,% of the samples fall into the C3–S1 water class, indicating water with a high salinity hazard and a low sodium hazard.

Groundwater Geochemistry and Saltwater Intrusion in the Dakar Coastal Area, Senegal

Groundwater levels and water samples were collected from 20 drinking water pumping and piezometer wells in the urban area of Dakar coastal region in the year 2019. The pH-value, electrical conductivity, as well as calcium, magnesium, sodium, potassium, chloride, sulfate, bicarbonate, and nitrate concentrations were measured to assess the hydrochemical quality of the infrabasaltic aquifer in the area. The present work carried out a hydrochemical analysis to interpret the groundwater chemistry of the aquifer. The results of this chemical analysis indicate that Na+ > Mg2+ > Ca2+ > K+ was the most dominant cation sequence in the groundwater, while Cl- > HCO3- > SO42- > NO3- was the most dominant one for anions. The chemical analysis of our samples showed, that the Cl-Ca-Mg facies was dominant in the aquifer, while Cl-Na-K and HCO3-Na-K facies represent 20% and 10% of the groundwater sampled, respectively. A comparison of the measured groundwater quality in relation to WHO drinking water quality standards revealed that 80% of the water samples are suitable for drinking purposes. Ca enrichment, Simpson ratio, ratio of sodium chloride, and calculating Base Exchange (BEX) indices for the samples revealed that the groundwater is mainly affected by three factors: seawater intrusion due to aquifer overexploitation on one hand, and freshening processes and nitrate pollution, on the other, mainly caused by the groundwater flow from the unconfined aquifer.

Evaluation of Processes Affecting the Variation of Groundwater Quality in Quang Nam, Da Nang, Vietnam

Groundwater quality is vulnerable to various processes. In this study, processes affecting groundwater quality were evaluated in coastal aquifers of Quang Nam - Da Nang (QNDN). A chemical data of 426 groundwater samples from 27 monitoring wells in the period 2011-2018 were analyzed. Principal Components Analysis (PCA) and Base Exchange Indices (BEXD) were applied for the evaluation. The PCA results suggested the influences of natural processes and anthropogenic activities on the groundwater quality. Seawater influence contributed to the dominant ions in groundwater; mineral weathering and dissolution mainly increased the alkalinity, Ca2+, and Mg2+; SO42- reduction explained the low SO42- in the groundwater; and reductive dissolution of Fe (hydroxides) caused Fe exceeding WHO’s drinking standard. Intensive groundwater abstraction generated up coning of saline groundwater; discharge from agricultural practices, industrialization, and urbanization were considered as sources of high NO3- in groundwater. The integration of monitoring data and BEXD gave a better interpretation of salinization and freshening, which can be masked by the memory effects of seawater transgression and regression in history.

Predictive model for progressive salinization in a coastal aquifer using artificial intelligence and hydrogeochemical techniques: a case study of the Nile Delta aquifer, Egypt.

To monitor groundwater salinization due to seawater intrusion (SWI) in the aquifer of the eastern Nile Delta, Egypt, we developed a predictive regression model based on an innovative approach using SWI indicators and artificial intelligence (AI) methodologies. Hydrogeological and hydrogeochemical data of the groundwater wells in three periods (1996, 2007, and 2018) were used as input data for the AI methods. All the studied indicators were enrolled in feature extraction process where the most significant inputs were determined, including the studied year, the distance from the shoreline, the aquifer type, and the hydraulic head. These inputs were used to build four basic AI models to get the optimal prediction results of the used indicators (the base exchange index (BEX), the groundwater quality index for seawater intrusion (GQISWI), and water quality). The machine learning models utilized in this study are logistic regression, Gaussian process regression, feedforward backpropagation neural networks (FFBPN), and deep learning-based long-short-term memory. The FFBPN model achieved higher evaluation results than other models in terms of root mean square error (RMSE) and R2 values in the testing phase, with R2 values of 0.9667, 0.9316, and 0.9259 for BEX, GQISWI, and water quality, respectively. Accordingly, the FFBPN was used to build a predictive model for electrical conductivity for the years 2020 and 2030. Reasonable results were attained despite the imbalanced nature of the dataset for different times and sample sizes. The results show that the 1000 μS/cm boundary is expected to move inland ~9.5 km (eastern part) to ~10 km (western part) to ~12.4 km (central part) between 2018 and 2030. This encroachment would be hazardous to water resources and agriculture unless action plans are taken.

Analysis of groundwater quality for irrigation purpose in Pennagaram block of Dharmapuri District, Tamilnadu, India

Groundwater is an indispensable source of water due to its substantial use for domestic, irrigation, and industrial purpose. This study is determined to examine the irrigation quality of groundwater in the seasons of pre-monsoon (PRM) and post-monsoon (POM) in the year 2013 at Pennagaram block of Dharmapuri district, Tamilnadu. A few samples of groundwater from the study area are analyzed for their physicochemical parameters (APHA, 1998). The parameters to examine irrigation quality of the samples taken in this study are Cl−/HCO3− ratio, percent sodium (%Na), Index of Base Exchange (IBE), Residual Sodium Carbonate (RSC), Kelly’s ratio (KR), Permeability Index (PI), Sodium Adsorption Ratio (SAR), Potential Salinity (PS), Magnesium Ratio (MR), Salinity Index and Sodicity Index. The classification of groundwater samples for irrigation was identified using the USSL Diagram, Doneen’s plot, and Wilcox diagram. The spatial distribution map gives a clear depiction of the groundwater quality for irrigation purposes, in both seasons. The plot of Cl−/HCO3− versus Cl− indicates that the groundwater samples are strongly affected by salinity. It illustrates the exchangeable mechanism which has one of the responses for the chemical composition of groundwater in the study area. According to %Na, RSC, KR, SAR, PI, MR, Salinity index, and Sodicity index makes the groundwater of the study area was safe for irrigation. According to the results of PS and Sodicity index the groundwater of marginal quality i.e., closely unfit for irrigational purpose.

Assessment of irrigational indices in surface water and shallow groundwater in the alluvial plain of Barak Valley, Assam, Northeast India

The main sources of water resources of the Barak Valley of Northeast India for irrigation are the surface water bodies in the form of ponds, lakes, rivers, and groundwater. This paper elucidates insight into the irrigational parameters to classify the types of water, based on these indices. Total hardness shows that 90% of surface water belongs to the soft and 63% of groundwater samples belong to the soft category. C‐S plot shows 33% of surface water belongs to C1‐S1 and 66% of groundwater samples belongs to C1‐S1 and C2‐S1, indicating fresh and suitable for use. The percentage Na+ shows most samples belong to good and permissible categories. Permeability index shows 81% of surface water in Class II and 18% in Class III, indicating good and bad types, respectively. Kelly's index suggests 90% of surface water is suitable and 9% is unsuitable, while 14% of piedmont groundwater is unsuitable. Magnesium hazard reveals 18% of surface water has more than 50 Magnesium absorptio ratio, leading to unsuitable, while 28% of piedmont and 33% of flood plain groundwater samples belong to unsuitable. Residual sodium carbon suggests surface water as suitable, while 48%, 12%, and 6% of groundwater belong to suitable, marginal, and unsuitable categories, respectively. Irrigation Water Quality Index values indicate that surface water is characterized by a highly restricted class, as they are exposed to surficial contamination as compared to groundwater. Base exchange index of ions indicates Na+‐SO4−2 hydro‐facies type suggesting dissolution of salt minerals in weak acidic water. Meteoric genesis index of ions reveals the source of groundwater as deeper meteoric water. Thus, the present study indices that the surface water bodies such as ponds, lakes, and swamps are more prone to contamination, leading to unsuitability for irrigational use, as compared to shallow groundwater in the study area, and therefore, appropriate measures must be adopted to reduce the quality deterioration for maximum utilization.

Fluoride distribution and groundwater hydrogeochemistry for drinking, domestic and irrigation in an area interfaced near Brahmaputra floodplain of North-Eastern India

Prevalence of fluoride mobilization and effect on groundwater quality at an area (Rangia) interfaced near Brahmaputra floodplain in North-Eastern region of India was examined for drinking, domestic and irrigation purposes. Groundwater samples were collected from tube-well during the pre-monsoon (PM), monsoon (M), and post-monsoon (POM) seasons and were further analyzed for various water quality parameters. Results showed that the pH of groundwater varies from almost neutral to slight alkaline condition. Further, EC, TDS, and total hardness results showed that almost all samples of three season comes within the permissible limit. In PM and POM, the concentration variation trend was observed as: HCO3− > Na+ > Ca2+ > Mg2+ > Cl− > SO42− > F− > K+ while in M season; HCO3− > Ca2+ > Na+ > Mg2+ > Cl− > SO42− > F− > K+ was observed. The base-exchange indices showed 93.3%, 73.3%, and 100% in PM, M, and POM, respectively, belonging to Na+ – HCO3− type. Other parameters, viz. water quality index, SAR value, RSC value, %Na, Kelly’s index, base-exchange and meteoric genesis indices and Gibbs ratio were also calculated. The results of three season groundwater quality parameters suggets that the maximum samples were found suitable for drinking, domestic and irrigation.

Assessment of seawater intrusion using ionic ratios: the case of coastal communities along the Central Region of Ghana

Seawater intrusion is a worldwide phenomenon resulting in groundwater quality challenges in coastal aquifers, which has prompted many investigations into its occurrence, sources, and age. To identify the origin of saline groundwater in the coastal communities of Central Region, Ghana, a combination of ten (10) different major ionic ratios—viz. Na/Cl, Mg/Cl, Ca/Mg, K/Cl, SO4/Cl, Ca/ (HCO3 + SO4), (Ca + Mg)/Cl, Cl/ (SO4 + HCO3), Na/Ca and Ca/SO4–and Base Exchange Index (BEX) computed from physico-chemical data on sixty-nine (69) boreholes in the communities have been analysed. The results show elevated levels of chloride concentrations in most of the groundwater in the study area, indicating salinization process by seawater intrusion. Also, the concentrations of the major ions (Na+, Ca2+, Mg2+, and SO42−) constituted more than 80% of the total dissolved solids and correlated well with Cl−, indicating they are from a common source. The spatial variation of the combined effect of the different ionic ratios and BEX classifications showed that, most of the groundwater with high salinity may be due to seawater intrusion. Significantly, the study has delineated areas in the communities with poor groundwater quality arising from seawater intrusion; these areas need to be avoided in the development of the resource for water supply.

Assessment of interaction between the aquifers by geochemical signatures in an urbanised coastal region of India

Multi-layered coastal aquifers are complex aquifer systems with two or more aquifers divided by the impermeable or semi permeable layers. The objective is to assess the interaction between the aquifers using geochemical indicators in the urbanised multi-layered coastal aquifer of Sankaraparani river basin, India. Hydrogeologically, the coastal part of this region comprises of alluvium formation as upper aquifer and sandstone formation as lower aquifer. Groundwater samples were collected from 33 representative wells during June 2017 and January 2018. Electrical conductivity, pH, and alkalinity were measured in the field while the concentration of major ions was analysed in the laboratory. The groundwater level in the upper aquifer varies from 7.4 to 18 m msl. Na-Cl type groundwater is dominant in the upper aquifer whereas Ca-HCO3 and mixed Ca-Na-HCO3 type groundwater is dominant in lower aquifer. The processes that controls the groundwater chemistry are sulphate reduction, freshening ion exchange, calcite dissolution and conservative mixing of seawater and freshwater. Significantly different values of electrical conductivity, sodium and chloride ratio, base exchange index as well as the different geochemical facies between the upper and lower aquifer indicates the absence of interaction between the aquifers near to the coast. Whereas in the west, the similarity in these confirms the interaction and both the formation function as single aquifer. The groundwater in the upper aquifer is affected by seawater intrusion upto 2 km whereas the lower aquifer is not affected.

Assessment of groundwater quality for drinking and irrigation purpose using hydrochemical studies in Dera Bassi town and its surrounding agricultural area of Dera Bassi Tehsil of Punjab, India

Present research aims to assess the suitability of groundwater of Dera Bassi town (Punjab) and its surrounding agricultural area for drinking as well as irrigation purpose. Thirty groundwater samples were collected (in February 2020) and analyzed for various physicochemical parameters. Results of physicochemical analysis were compared with Indian (IS 10500:2012) as well as WHO (2006) standards to ascertain the suitability of the groundwater samples for drinking purpose, and it has been found that results for almost all the parameters except alkalinity (at few sites) are within the permissible limit. The pattern of ionic dominance was observed in the order of Ca2+ > Mg2+ > Na+ > K+ for cations and Cl− > NO3− > SO42− > F− for anions. Further, according to the observed Kelly’s ratio, sodium adsorption ratio, sodium percentage, corrosivity ratio and permeability index, the groundwater samples were found to be fit for irrigation purpose. However, the magnesium ratio and residual sodium carbonate revealed that groundwater of the area under study is not fit for irrigation purpose at some sites. The plot of SAR values versus EC values in the US Salinity Laboratory diagram revealed that the majority of the samples fall under water type C3-S1 (high salinity—low SAR) and 36.77% samples fall under water type C2-S1 (medium salinity—low SAR). Gibb’s diagram revealed that all samples fall under rock dominance category. The values of index of base exchange (CAI 1 and CAI 2) indicate that both direct ion and reverse ion exchange processes are taking place in the region.

Geo-spatial distribution of arsenic contamination of groundwater resources in intricate crystalline aquifer system of Central India: Arsenic toxicity manifestation and health risk assessment

The behavior of As in aqueous media in the complex crystalline aquifers like that of the present study area is not yet understood properly. To that end, groundwater and river water samples from two different seasons are analyzed for As and physicochemical parameters. The groundwater in the area is evolved by simple dissolution or mixing of two or more different facies (Ca2+–Mg2+–Na+–SO4 2–). However, the majority of samples with the base-exchange indices (85%) and meteoric genesis indices (77%) value less than unitary (<1) divulges that Na+– SO4 2– type water and deeper meteoric percolation. The estimation of As in groundwater (<0.1–202 ppb) shows the spatial and temporal inconsistency with 17.31% (pre-monsoon) and 11.67% (post-monsoon) of the samples surpassed the permissible limit of 10 ppb. Furthermore, health risk associated with As in terms of hazard quotient (HQ) values > 1 (pre-monsoon: 21.15% and post-monsoon: 20%) for children and carcinogenic risk values >1.00 × 10−6 for different seasons (44.25% and 33.33% of samples) represents a serious health risk. Furthermore, the different stages of Keratosis and Melanosis diseases reported in the study area establish the severity of As toxicity on the local populace. The study concludes geogenic arsenic contamination in the study area is primarily associated with Rhyolite and its comagmatically formed Dongargarh granite batholith emplacements.

Natural and anthropogenic factors driving groundwater resources salinization for agriculture use in the Campania plains (Southern Italy)

The Mediterranean region is under pressure for a more sustainable use of water resources in view of the actual and future climate change. Under this pressure, the need to better assess the links between groundwater availability and quality and irrigated agriculture, is becoming urgent. Through the hydrogeologic and hydrochemical characterization of the coastal aquifers of a representative Mediterranean study area (the Campania Region in southern Italy), this study strengthened the analysis of basic components of the groundwater cycle and their temporal variability, including hydrologic, environmental and socio-economic aspects. Selected physiochemical properties of groundwater in 52 monitoring wells were considered from the Campania Environmental Protection Agency database. A total of 626 samples were collected from 2004 to 2018 to capture the water quality variability. Factor analysis and a specific groundwater quality index were also applied on 23 samples in two different timelines (2006, 2016) to capture the hydro-chemistry evolution through year. Moreover, land use and active pumping wells locations were used in the analysis. Spatial and temporal trends of base exchange indices (BEX) and sodium adsorption ratio (SAR) were computed along with Pearson coefficient among different variables, like well densities and distance from the coast. The variation in the distribution of salinity between 2006 and 2016, along with highly positive and highly negative BEX and groundwater quality index values, indicate unstable conditions for the future. In the greenhouse's areas, where groundwater exploitation is elevated, an increase of salinity was recorded due to seawater intrusion. In volcanic districts water rock interaction is the main driver of groundwater salinization, while mixing processes with carbonate freshwaters diminish groundwater salinities in the alluvial plains. This study demonstrates that groundwater over pumping can have a major impact on groundwater quality used for irrigation, despite the dominant influence that local geological and morphological features exert on the area.

Appraisal of Groundwater Quality with Human Health Risk Assessment in Parts of Indo-Gangetic Alluvial Plain, North India.

Groundwater contamination in the Indo-Gangetic alluvial plain has reportedly been affected by various factors, such as mineral dissolution, overexploitation, precipitation, and ion exchange. This study was designed to interpret the hydrochemical fluctuations in the groundwater sources of a rural area in Raebareli district. Groundwater is slightly alkaline and affected by the issues of fluoride, salinity, hardness, and nitrate. The Pollution Index of Groundwater significantly categorize 57% and 79% of the samples under the "insignificant pollution" category during pre-monsoon and post-monsoon periods. The Health risk assessment indicated the high susceptibility of children toward health risks. It also indicated that fluoride had greater impact than nitrate in the study area. The multivariate statistical analysis indicates that anthropogenic activities, such as agricultural practices, including excessive fertilizer application and improper domestic and cattle waste management, are probable causes of groundwater contamination through NO3-, Cl-, Na+, and K+. Furthermore, the base exchange index classified 71.43% samples in pre-monsoon and 78.57% in post-monsoon as Na-HCO3 type. The meteoric genesis index suggested that 78.57% and 85.71% of the samples belong to shallow meteoric water percolation type during pre- and post-monsoon periods, respectively. The Piper plots revealed that HCO3-Ca·Mg and SO4·Cl-Na + K type are the prominent facies in the area, with dominance of alkalis and weak acids. According to Gibbs plot, majority of the samples fall under "rock dominance" suggesting that "rock-water" interaction was the dominant natural process controlling the groundwater chemistry.

Qualitative assessment, geochemical characterization and corrosion-scaling potential of groundwater resources in Ghaziabad district of Uttar Pradesh, India

The sustainable usage of groundwater is facing a rapid decline in quantity and quality due to demographic and industrial expansion. In India, among several residential-industrial hubs, Ghaziabad is one of the suburban districts and industrial town of Uttar Pradesh, largely dependent upon groundwater for its water needs. The present study was carried out to assess the groundwater in terms of qualitative, geochemical and to identify corrosion-scaling potential during the pre- and post-monsoon seasons of 2017. Majority of the samples showed the exceeding levels of EC, TDS, TH, Cl, Na, and K, inferring the seasonal variability. Geochemical characterization indicated the origin of the groundwater from the rock-water interface of the underlying aquifers and hydrochemical types of water facies: Ca–Mg–HCO3 > Na + K–HCO3 > Na + K–Cl–SO4 were found predominant. Based on the classification of groundwater, most of the samples indicated Na+-HCO3- and shallow meteoric type of nature. Schoeller's index of base exchange also showed the chloro-alkaline disequilibrium with indirect base exchange hardened water. Subsequently, to predict the corrosive-scaling behaviors of the groundwater; five water stability indices were applied namely; Langelier saturation index (LSI), Ryznar stability index (RSI), Puckorius scaling index (PSI), Larson-Skold index (LS) and Aggressive index (AI). The results illustrated that the bulk of the samples exhibited scaling trend as per LSI, LS, and AI, alike RSI and PSI that registered slight corrosive properties of the groundwater. Spatial-temporal mapping of the indices also reflected the temporary scaling potential. Statistically, the interrelationships among the parameters and indices were evaluated using Spearman's correlation which confirmed the scaling effects through strong-significant associations among cation-anion complexes that promote temporary scaling. Therefore, estimation of quality levels and influences in the chemical integrity helps to underline the causative effects and ensure the sustainable consumption of the groundwater in various purposes through prior quality monitoring and applied preventive measures.

Identifying major factors controlling groundwater chemistry in predominantly agricultural area of Kattumannarkoil taluk, India, using the hydrochemical processes and GIS

ABSTRACT Hydrochemical investigation was carried out in predominantly agricultural area of Cuddalore district, South East India. The objective was to determine the potential factors controlling groundwater chemistry and their seasonal variation. Fifty samples obtained from 37 agricultural boreholes and 13 surface waters were used for analyses of 13 physico-chemical parameters. Qualitative and quantitative methods such as titration methods, flame photometry and Ultra-violet visible spectrometry were used to define the major ions; Na+, Ca2+, Mg2+, Cl−, K+, SO4 2+, PO4, Si(OH)4 and NO3 −. The results further were subjected to geographic information system (GIS), statistical analysis and geochemical plots. The evaluation of factors controlling water chemistry was accomplished by interpreting Gibb’s diagram, Piper diagram, Index of Base Exchange (IBE) and factor analysis. The interpretation proved that salts percolation, agriculture, weathering and dissolution as predominant factors controlling water quality of the study area. A Piper diagram classified the study site’s water types into Ca-HCO3 water type, Ca-Cl water type and mixed Ca-Mg-Cl water type indicating freshwater recharge, mineral dissolution and reverse ion exchange, respectively. Factor analysis extracted four significant factors, namely leaching of secondary salts, weathering, and mineral dissolution as well as anthropogenic factors, that cumulatively responsible for 80.34% of the total variance of the taluk’s groundwater chemistry.