Hydrochemical Characteristics Of Groundwater Research Articles

Hydro-chemical characterization of groundwater using multivariate statistics in Hawassa City, Southern Ethiopia

ABSTRACT This study characterized the hydro-chemical characteristics of groundwater for assessing the possibility of managed aquifer recharge in Hawassa City. A total of 48 water samples were taken from hand-dug wells and boreholes and examined to determine the water type, critical metrics, and key determinants of water quality. Multivariate statistical techniques such as hierarchical cluster, principal component, and linear discriminant analysis were used. The samples were divided into four variable groups and four case cluster groups. The results depicted the water hardness group (C1), soil salinity group (C2), weak and strong acids forming group (C3), and pollution indicator group (C4). Four water types were identified, Na–HCO3 and Ca–Na–HCO3 (87.5%), Ca–HCO3, and Na–Cl. Na–HCO3 was the dominant in hand-dug wells than in deep boreholes, which may account for evaporation or contaminations. Seven principal components with a cumulative variance of 78.58% were also formed. The first two, hardness and salinity, contributed 25.4 and 11.4% variance, respectively. In linear discriminate analysis, three discriminate functions with eight variables were generated, namely pH, K+, Na+, Ca2+, HCO3−, Cl−, BOD5, and COD. Thus, it is revealed that the decline in water quality attributed to natural and anthropogenic causes that require regulation enforcement and higher recharge to reverse the situation.

Hydrochemical Characteristics of Groundwater in Northwestern Kazakhstan Aquifers: Implications for Livestock Water Supply

Hydrochemical Characteristics of Groundwater in Northwestern Kazakhstan Aquifers: Implications for Livestock Water Supply

Analysis on Spatial Variability of Hydrochemical Characteristics and Control Factors of Jinan Baotu Spring Area

To understand the karst groundwater hydrochemical characteristics and ion sources of the Jinan Baotu Spring area, this study focused on the three functional zones as an indirect recharge area, direct recharge area, and discharge area. Through water sample collection and testing, the spatial variability of groundwater chemical characteristics in different functional zones and the formation mechanism were analyzed using hydrochemistry parameter statistics, multivariate statistics, self-organizing map, hydrochemistry graphical analysis, ion ratios, and other methods, guided by the theory of groundwater flow system and combined with regional physical geography and hydrogeological conditions. The results showed that： the groundwater of each functional zone was alkaline as is typical in the dissolution of carbonate minerals. Owing to the different groundwater runoff pathways, the variability of water chemistry parameters in different functional areas was obvious. The groundwater of the discharge area was recharged by both the direct recharge area and the indirect recharge area. The hydrochemistry type changed from HCO3-Ca type to HCO3·SO4-Ca type through the indirect recharge area to the discharge area. The presence of a small amount of gypsum dissolution within the aquifer generated Ca2+ and SO42-. The ions in groundwater mainly came from the dissolution and filtration of aquifer rock minerals, and at the same time, they were affected by cation exchange, mineral dissolution equilibrium, and the combined effects of human activities. The groundwater in the Baotu Spring area was greatly influenced by human activities, which to some extent affected the evolution of groundwater hydrochemistry in the spring area.

Identifying the spatio-seasonal pattern of hydrochemical evolution and surface water-groundwater interaction in a large urban river basin, Northwest China

There is insufficient understanding of the spatio-temporal evolution of surface water-groundwater quality and hydraulic connection under both natural and human influences in urban river basins. To this end, this paper investigated the spatio-seasonal pattern of hydrochemical evolution and surface water-groundwater interaction in a typical urban river basin (Dahei River basin) based on isotopic and hydrochemical data of 132 water samples collected during three seasons (normal, wet and dry seasons). From the normal season to the wet season, surface water in the Dahei River basin was dominated by the impacts of evaporation and groundwater discharge processes. During this period, the precipitation and agricultural activities (canal irrigation) were frequent. Thus, groundwater was affected by irrigation infiltration of surface water and precipitation from high-altitude areas. From the wet season to the dry season, precipitation decreased and irrigation methods changed (canal irrigation → well irrigation). In this case, groundwater discharge had a stronger impact on surface water, and shallow groundwater was recharged by deep groundwater through the well irrigation. Under this hydrological pattern, the hydrochemical characteristics of surface water were mainly influenced by evaporation, human activities (agricultural irrigation and sewage treatment) and groundwater discharge. In contrast, the hydrochemical characteristics of groundwater were main influenced by water-rock interactions (dissolution of evaporites and silicates, and cation exchange) and human activities. This study contributed to a better understanding of the hydrochemical and hydrological processes in urban river basins and provided a theoretical basis for the sustainable management of water resources.

Hydrochemical Characteristics of Groundwater and Its Influencing Factors in Yuanzi River Basin, Shuozhou, Shanxi, China

Hydrochemical Characteristics of Groundwater and Its Influencing Factors in Yuanzi River Basin, Shuozhou, Shanxi, China

Origin and Geochemical Characterization of Groundwater from Coal Seam: A Case Study of Balasu Coalfield, Ordos Basin.

The hydrochemical characteristics of groundwater are of great significance for studying the source, development, and utilization of groundwater. This study investigated the characteristics of anions and cations, total dissolved solids (TDS), hydrochemical types, and hydrogen and oxygen isotopes of surface water and groundwater in the Balasu coalfield. By conducting experiments using inductively coupled plasma emission electron spectrometry, ion chromatography, acid-base titration, and gravimetric analysis, the characteristics of ion concentration and TDS in different aquifers were analyzed to determine the possible source of groundwater in C2 (number 2 coal seam in Yan'an Formation). The Piper trilinear diagram was used to determine the hydrochemical types of aquifers, and the source of groundwater was determined based on the stable isotope characteristics of hydrogen and oxygen. The changes in ion, TDS, hydrogen, and oxygen isotopes of surface water and groundwater were analyzed, and the groundwater differences between the two sets of coal seams were compared. The research results indicate that the groundwater in C2 (number 2 coal seam in Yan'an Formation) is caused by the original sedimentary water and the infiltration of Zhiluo Formation and A1 (strata at the top of the Yan'an Formation to number 2 coal seam). However, C4 (number 3 coal seam in Yan'an Formation) is hindered by the well-developed mudstone in A3 (bottom of number 2 coal seam to the top of number 3 coal seam), which hinders the infiltration of groundwater. The study emphasizes that the overlying strata can have a significant impact on the coal seam when the moisture content is high and there is a lack of overlap, thereby promoting changes in the moisture content of the coal seam. This study provides some insights into the safety of coal mines, especially in mining areas with a high coal seam moisture content.

Study of Environmental Isotopes and Hydrochemical Characteristics of Groundwater from Springs at Archaeological Sites in Dompu Regency, West Nusa Tenggara, Indonesia

The existence of groundwater sources in several springs at archaeological sites in Dompu Regency, West Nusa Tenggara, Indonesia, has been widely used by the surrounding community for various needs. However, from a number of the springs, there are springs whose water discharge has decreased. Meanwhile, from a number of existing springs, there is one spring whose groundwater is used every day even though it tastes a bit brackish. For this reason, it is important to conduct a groundwater study in the area with the aim of knowing the characteristics, preliminary identification of recharge areas and quality of groundwater in the study area through an environmental isotope and hydrochemical. The study was conducted by taking a number of groundwater samples from several archaeological sites in Dompu Regency. The results of environmental isotope and hydrochemical analysis show that there are 2 springs (2 archaeological sites), namely the Riwo and Ncona springs, because these two areas are part of the recharge area, which must be preserved by not clearing forest land. Meanwhile, for the quality of groundwater, of the 5 springs located at the archaeological sites, only the Hodo spring is of “poor quality” with the Na–Cl water type; it is unfit for drinking water.

Evolution of groundwater hydrochemical characteristics and formation mechanism during groundwater recharge: A case study in the Hutuo River alluvial–pluvial fan, North China Plain

A pilot project for groundwater recharge from rivers is currently being carried out in North China Plain. To investigate the influence of river recharge on groundwater hydrochemical characteristics, dynamic monitoring and analysis of groundwater samples were conducted at a typical recharge site in the Hutuo River alluvial-pluvial fan in the North China Plain from 2019 to 2021. Hydrochemical, isotopic, and multivariate statistical analyses were used to systematically reveal the spatiotemporal variation of groundwater chemistry and its driving factors during groundwater recharge process. The results showed that the groundwater hydrochemical types and characteristics in different recharge areas and recharge periods exhibited obvious spatiotemporal differences. The groundwater type varied from HCO3·SO4-Na·Mg to HCO3·SO4-Ca·Mg in an upstream ecological area, while the groundwater type changed from SO4·HCO3-Mg·Ca to HCO3·SO4-Ca·Mg in the downstream impacted by reclaimed water. Changes in the contents of Ca2+, Mg2+ and HCO3− were mostly controlled by the water–rock interactions and mixing-dilution of recharge water, while the increases in Na+, NO3−, Cl−, SO42− and NO3− contents were mainly due to the infiltration of reclaimed water. Nitrogen and oxygen isotope (δ15N and δ18O) tests and the Bayesian isotope mixing model results further demonstrated that nitrate pollution mainly originated from anthropogenic sources, and the major contribution came from manure and sewage, with an average proportion of 64.6 %. Principal component analysis indicated that water–rock interactions, river-groundwater mixing and redox environment alternation were dominant factors controlling groundwater chemical evolution in groundwater recharge process.

Impact of Hydrogeological Characteristics on the Development of Underground Space Resources in Valley Cities

The development of urban underground space is a crucial aspect of current urban development. However, various factors pose challenges during the development process. In particular, in the valley cities of western China, groundwater has a significant impact on the utilization of underground space. This study focuses on understanding the influence of hydrogeological characteristics on the development of underground space in Ledu District, Haidong. Firstly, the hydrogeological characteristics of the aquifer in the study area are analyzed to determine the recharge and discharge characteristics. The dynamic changes in the groundwater table over time are then examined. Subsequently, the hydrochemical characteristics of groundwater are investigated to expound on the influence mechanism of groundwater on the development of underground space resources in Ledu District. The study reveals that the hydrodynamic effect of groundwater in the study area is substantial and has a significant physical scouring effect on underground structures. The fluctuation of groundwater levels affects the stability of buildings by increasing groundwater buoyancy. Additionally, this fluctuation also leads to engineering and environmental problems such as differential settlement and land salinization. The chemical characteristics of groundwater primarily impact the stability of building foundations through the corrosive effects of groundwater composition. This research clarifies the influence mechanism of groundwater on the development of underground space in typical valley cities of western China. The findings have practical significance for the evaluation, planning, development, and utilization of urban underground space resources in Haidong.

Hydrochemical Characteristics of Groundwater in and around the Peenya Industrial Area in Bengaluru City

The present study aims to use the Water Quality Index (WQI) modeling method to know about groundwater hydrochemistry and drinking suitability in and around (5 km) the Peenya industrial area/estate in Bengaluru city. For this research study, 116 bore well samples were collected and examined for the pre (dry) and post (wet) monsoon seasons in 2021, following APHA standard procedures. According to the BIS standard, the TH, Ca, Mg, NO3, and TDS exceed the desirable limits in both seasons. The water quality examination data shows that TDS concentration is found to be higher above the desired limit (500 mg/l) during the pre- (63%) and post- (45%) monsoon seasons. Furthermore, 55% (pre-monsoon) and 15% (post-monsoon) of the groundwater samples exceed the BIS’s nitrate allowable limit (45 mg/l). Among the analyzed samples, the calcium content in 19% and 20% of samples exceeded the desirable limit (75 mg/l), and magnesium content in 87% and 83% exceeded the desirable limit (30 mg/l) in pre- and post-monsoon seasons. In 95% of samples, TH content exceeded the desirable limit (200 mg/l) in both pre- and post-monsoon seasons. Piper diagram plots were utilized to determine sources of dissolved constituents, rock-water interaction, and other factors that influenced the region’s groundwater composition. Based on hydro-chemical facies the Ca-Mg-HCO3 type of water predominates in the study area during pre (dry) and post (wet)-monsoon seasons of the year 2021. The chemistry of groundwater has deteriorated significantly because of several industrial and anthropogenic activities. The WQI spatial distribution map shows that groundwater quality has the greatest impact in the west and a few places in the north and south regions of the research area. This study was conducted in Bangalore’s Peenya industrial area to determine whether groundwater is suitable for drinking, identify the mechanisms governing groundwater’s geochemistry, and evaluate the effects of an industrial area on groundwater quality. The primary focus of this study is the major ion chemistry in this field.

Spatial–Temporal Changes in Shallow Groundwater Quality with Human Health Risk Assessment in the Luxi Plain (China)

Groundwater is an essential water source for drinking, domestic, irrigation and industrial production in Luxi Plain, Shandong Province, China. Understanding the spatial–temporal changes in groundwater quality and its influencing factors in the region were required for better utilization of groundwater resources and efficient design of groundwater management strategies. In this study, the hydrochemical characteristics of groundwater in the study area were analyzed, and significant evolution was found from 2018 to 2020 due to silicate and carbonate weathering, evaporation and human activities. Moreover, the entropy water quality index (EWQI) was used to assess groundwater quality from 2018 to 2020. The EWQI values in 2018–2020 were 129.5, 90.5 and 94.0, respectively, and 31.7% of the groundwater in 2019 and 20.0% in 2020 can be used directly for drinking in the study area; others can be used for domestic water or irrigation. The potable groundwater, with an EWQI value of <50 (ranked as class Ⅰ or Ⅱ water quality), was mainly distributed in the west and southeast of the study area. The potential health risk due to oral intake and dermal intake was further assessed based on the human health risk assessment (HHRA) model. The results showed that, 37.3%, 6.7% and 3.3% of the groundwater samples for adults exceeded the acceptable limit for non-carcinogenic risk of 1.0 in 2018–2020, while for children, they were 88.2%, 30.0% and 56.7%, respectively. The high non-carcinogenic risks virtually all occurred in the counties or districts with higher agricultural or economic values. This work may provide useful information for local groundwater conservation and management and help to ensure a sustainable and healthy water supply for drinking, domestic and agricultural needs.

Combined cluster and discriminant analysis based on hydrochemical and isotopic evidence: A case study of the Yellow River Delta in China

Groundwater serves as an indispensable resource, fundamental for both sustaining life and underpinning various human endeavors. However, escalating demands, coupled with climate change, have given rise to significant water scarcity in numerous areas, including the Yellow River Delta (YRD) in China. This study aims to characterize the hydrochemical composition and stable isotopes (δ2H and δ18O) of groundwater in YRD and identify spatial clustering patterns using combined Hierarchical Cluster Analysis (HCA) and Discriminant Analysis (DA). Comprehensive analyses were conducted on the major ions (i.e., K+, Na+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-), water quality indicators (i.e., pH, electrical conductivity (EC), and oxidation-reduction potential (ORP)) and isotopic composition of groundwater samples. Applying HCA on a collection of 38 water samples, the study delineated six distinct clusters, each bearing unique hydrochemical characteristics. DA was used to establish a discriminant model, achieving a classification accuracy of 80% for new groundwater samples. The study underscores that there are localized variations in the hydrochemical characteristics of groundwater in YRD, attributed to different geological conditions and anthropogenic influences. Such insights are instrumental in crafting effective strategies for water resource management, environmental conservation, and sustainable development in YRD and other analogous regions confronted with groundwater challenges.

Hydrochemical characteristics and the impact of human activities on groundwater in a semi-arid plain: a case study of western Jilin Province, Northeast China.

Groundwater is important for human survival and development, particularly in arid and semi-arid regions. This study aimed to analyze the hydrochemical characteristics, influencing factors, and the impact of human activities on groundwater in the semi-arid plains of western Jilin Province, northwest China. The study collected 88 and 151 phreatic and confined water samples, respectively, which were analyzed for 13 water quality indicators using statistical and graphical methods. In order to investigate the impact of anthropogenic activities on water quality and health risks, the improved combined weighted water quality index (ICWQI) based on the entropy weight, criteria importance though inter-criteria correlation (CRITIC), the coefficient of difference method, subjective weight based on quality grading criteria, and the water quality index (WQI) were proposed to evaluate the water quality of the study area. Meanwhile, the human health risk assessment (HHRA) model was used to assess the risks of nitrate to the health of humans in different ages and sex categories. The results indicated that the groundwater in the study area was weakly alkaline and the main hydrochemical types in the phreatic and confined water were HCO3-·Ca-Mg and HCO3--Na. Rock weathering was the dominant process responsible for the generation of groundwater ions, the ions in groundwater primarily originate from the dissolution of halite, gypsum, and feldspar, while dolomitization promotes an increase in Mg2+. Human activities lead to an increase in NO3- in groundwater and have an impact on water quality and human health risks. The ICWQI method was found to yield more precise and rational assessments of water quality. Groundwater quality is primarily affected by nitrate ions. The areas in which groundwater nitrate posed a higher risk to human health were found to be mainly in the saline-alkali lands of Qian'an, Tongyu, and Zhenlai. Fertilizers, pesticides, and livestock farming activities contribute to the pollution of surface water. This surface contamination then infiltrates abandoned confined wells, leading to contamination of the confined aquifers. This study can improve the understanding of groundwater hydrochemical characteristics and the impact of human activities on groundwater in the study area. This study can also contribute to the study of groundwater in semi-arid regions.

Hydrochemical Characteristics and Formation Mechanism of Quaternary Groundwater in Baoshan Basin, Western Yunnan, China

The shallow groundwater of the quaternary system in the Baoshan basin, Yunnan Province is seriously polluted, threatening human health and restricting local socio-economic development; therefore, it is necessary to investigate the hydrochemical characteristics and formation mechanisms of the shallow groundwater of the quaternary system in the Baoshan basin. This study used EVS 2022 to establish a 3D visual geological model of the quaternary system in the basin and divided the shallow groundwater aquifers of the quaternary system into three groundwater systems, sampling 22, 9, and 4 groups in each groundwater system, respectively. Mathematical statistics, Piper’s trilinear diagram, Gibbs plots, the Gaillardet model, the ion ratio method, groundwater saturation, and the PCA-APCS-MLR model were used to analyze the groundwater hydrochemical characteristics and genesis of the study area. The results show the following: (1) The types of groundwater chemicals are mainly HCO3-Ca-Mg type and HCO3-Ca, the causes of the water chemical characteristics are mainly influenced by water–rock interaction and alternate cation adsorption, and the rock types with which the groundwater exchanges substances are carbonate rocks and silicate rocks. (2) The Fe2+, Mn2+, and NH3-N contents in groundwater systems I and II exceed the standard, which is the human activity area, and groundwater pollution is mainly affected by human activities. (3) Four main categories of factors were obtained according to the PCA-APCS-MLR model, namely dissolution filtration, migration and enrichment factors, geological and human activity factors, and environmental factors and pollution factors; the cumulative contribution of variance was 77.84%, and the groundwater chemical characteristics were jointly influenced by hydrogeological conditions and human activities. The results of this study provide a basis for groundwater protection and management in the Baoshan basin, where groundwater system I is the key area for pollution and should be strengthened for control.

Hydrochemical characteristics of groundwater in a plain river network region: Establishing linkages between source and water quality variables

The chemical characteristics of groundwater can indicate water quality condition and provide useful information for pollution source identification. This study aimed to understand the effects of dissolved organic matter (DOM) on ionic composition of groundwater and identify the main ions and sources of pollution. The Lake Taihu is a typical eutrophic lake in China. In this study, the hydrochemical composition of groundwater in the surrounding aquifer of Lake Taihu Basin was analyzed. The results showed that the values of water quality index (WQI) range from 13.29 to 56.26 (good water quality). The dominant hydrochemical type of groundwater was Ca–Mg–HCO3 type, and the rock dominance was the major mechanism controlling the groundwater chemistry. With an increasing concentration in dissolved organic carbon (DOC), the Na+, Mg2+, and HCO3– concentrations all showed a sharp increase followed by a slow increase, while the NO3– concentration showed an opposite trend, indicating the DOM can affect the ions composition. In addition, K+ was positively correlated with NO3–, As, and Cd. Hence, DOM input may directly or indirectly change the hydrochemistry of groundwater. Besides, the NO3– concentration in groundwater was much higher than that in Lake Taihu, indicating that the NO3– in groundwater mainly came from surface soil leaching. The anthropogenic sources are probably the main sources of different ions, including K+, NO3–, As, and Cd. This study can help to better understand the effects of lake eutrophication on groundwater and its pathways.

Hydrochemical Characteristics of Groundwater and Their Significance in Arid Inland Hydrology

Phreatic groundwater hydrochemistry is important for sustainable water utilization and ecological stability in arid regions. Based on the test data from collected water samples, this study explored the phreatic groundwater recharge, hydrochemical evolution, and quality of the Sugan Lake Basin using hydrogeochemical, isotopic, and multivariate statistical analyses. The stable isotopic results showed that the phreatic groundwater in the alluvial fan, plain, and wetland areas of the basin generally originated from modern water, and the phreatic groundwater in the piedmont was mainly recharged by paleowater under low-temperature conditions. Carbonate is the dominant mineral in the regional rock weathering process. Phreatic groundwater in the piedmont is controlled by mineral dissolution and cation exchange; however, phreatic groundwater in other areas of the basin is significantly affected by river infiltration. This indicates that the hydrochemical regime of phreatic groundwater is sensitive to natural river flow without disturbing human activity. Class I–V groundwater samples accounted for 2.86%, 25.71%, 34.29%, 14.29%, and 22.86%, respectively. Total dissolved solids, total hardness, sulfate, chloride, nitrite, Na, Fe, Hg, and Cr VI are important factors that determine groundwater quality. This study deepens the understanding of phreatic groundwater hydrochemical characteristics and hydrologic cycles in the Sugan Lake Basin and provides background values of hydrochemistry without human interference for further study in arid inland basins.

Groundwater Hydrochemical Characteristics and Water Quality in Egypt’s Central Eastern Desert

The rapid expansion of economic activities in Egypt’s Central Eastern Desert has resulted in poorly coordinated groundwater development, having a negative impact on the resource. This study was conducted to assess the hydrochemical characteristics of the different aquifers in the Central Eastern Desert, with an emphasis on the impact of seawater intrusion and groundwater quality for different purposes. A total of 21 groundwater samples were collected representing the three main aquifers (Eocene Carbonate, Nubian Sandstone, and Fractured Basement) in the Central Eastern Desert, and analyzed for major ions and trace elements. The majority of the samples had electrical conductivity values that exceeded the salinity limit for natural water. Groundwater saline load is primarily influenced by sodium, calcium, chloride, and sulfate concentrations. The groundwater in the Central Eastern Desert mainly consists of Na-Cl, Ca-Cl, and Na-SO4 water-types. Saltwater intrusion and water-rock interactions via cation exchange and minerals weathering are the primary controlling factors of groundwater hydrochemistry. The high salinity of this groundwater renders it unsuitable for irrigation or consumption. Additionally, it is unfit for domestic use based on total hardness values. Furthermore, the Al, Cd, Fe, Mn, and Ni concentrations in the investigated groundwater exceed the allowable limits for human consumption. Proper mitigation measures and adaptation strategies are required for groundwater sustainability in the Central Eastern Desert.

Assessment of shallow groundwater aquifer in an arid environment, Western Saudi Arabia

In arid and semi-arid regions like the Kingdom of Saudi Arabia (KSA), groundwater is considered the main source for drinking and agricultural uses due to low precipitation and limited surface water resources. The aim of this research is to evaluate the hydrogeological and hydrochemical characteristics of groundwater in Wadi Marawani basin for sustainable development. To achieve this goal, standard analytical methods have been used to determine the physicochemical parameters in sixty-four samples. Groundwater quality and controlling factors were evaluated using diagrams (Piper, Gibbs, Chadha, and HEF) and irrigation indices such as Sodium percentage (Na%), Soluble Sodium Percentage (SSP), Permeability Index (PI), Residual Sodium Bicarbonate (RSBC) and Kelly Index (KI). Also, the Support Vector Machine for Regression (SVMR) and the Multiple Linear Regression (MLR) models have been applied to predict the irrigation parameters. The results revealed that the Quaternary aquifer of unconfined condition is the main source of groundwater in Wadi Marawani basin. Depth to water measurements in sixty-two wells indicated that the groundwater flows from east to west towards the Red Sea coast. The ionic composition of the analyzed water samples showed that, Ca–HCO3, Na–Cl, mixed Ca–Mg–Cl–SO4, and Na–Ca–HCO3 are the main water types. Assessment of groundwater quality indicates that, 33%, 86%, 100%, 100% and 69% of groundwater samples are suitable for irrigation based on the calculated irrigation indices Na%, SSP, PI, RSBC and KI respectively. The SVMR model is outperformed the MLR in prediction of the irrigation indices. There was no overfitting or underfitting in the datasets used to measure, calibrate, and validate the SVMR model of four irrigation indices. Finally, this study can provide a holistic view of groundwater management for agricultural uses in the Wadi Marawani basin.

Hydrochemical Characterization of Groundwater in the Sub-Prefecture of Kokumbo (Ivory Coast)

Hydrochemical Characterization of Groundwater in the Sub-Prefecture of Kokumbo (Ivory Coast)

Chemometrics of the Environment: Hydrochemical Characterization of Groundwater in Lioua Plain (North Africa) Using Time Series and Multivariate Statistical Analysis

This study aims to analyze the chemical composition of Lioua’s groundwater in order to determine the geological processes influencing the composition and origin of its chemical elements. Therefore, chemometrics techniques, such as multivariate statistical analysis (MSA) and time series methods (TSM) are used. Indeed, MSA includes a component analysis (PCA) and a cluster analysis (CA), while autocorrelation analysis (AA), supplemented by a simple spectral density analysis (SDA), is used for the TMS. PCA displays three main factors explaining a total variance (TV) of 85.01 %. Factors 1, 2, and 3 are 68.72%, 11.96%, and 8.89 % of TV, respectively. In the CA, total dissolved solids (TDS) and electrical conductivity (EC) controlled three groups. The elements SO42−, K+, and Ca2+ are closely related to TDS, the elements Na+, Cl−, and Mg2+ are closely related to CE, while HCO3− and NO3− indicate the dissociation of other chemical elements. AA shows a linear interrelationship of EC, Mg2+, Na+, K+, Cl−, and SO42−. However, NO3− and HCO3− indicate uncorrelated characteristics with other parameters. For SDA, the correlograms of Mg2+, Na+, K+, Cl−, and SO42− have a similar trend with EC. Nonetheless, pH, Ca2+, HCO3− and NO3− exhibit multiple peaks related to the presence of several distinct cyclic mechanisms. Using these techniques, the authors were able to draw the following conclusion: the geochemical processes impacting the chemical composition are (i) dissolution of evaporated mineral deposits, (ii) water–rock interaction, and (iii) evaporation process. In addition, the groundwater exhibits two bipolar characteristics, one recorded with negative and positive charges on pH and Ca+ and another recorded only with negative charges on HCO3− and NO3−. On the other hand, SO42−, K+, Ca2+, and TDS are the major predominant elements in the groundwater’s chemical composition. Chloride presence mainly increases the electrical conductivity of water. The lithological factor is dominant in the overall mineralization of the Plio Quaternary surface aquifer waters. The origins of HCO3− and NO3− are as follows: HCO3− has a carbonate origin, whereas NO3– has an anthropogenic origin. The salinity was affected by Mg2+, SO42−, Cl−, Na+, K+, and EC. Ca2+, HCO3−, and NO3− result from human activity such as the usage of fertilizers, the carbonate facies outcrops, and domestic sewage.