Piper Diagram Research Articles

Spatiotemporal Evolution Mine Groundwater’s Hydrogeochemical Characteristics Under Influence of Mining and Grouting in Gubei Coal Mine, China

Geological conditions or human activities will affect the hydrochemical characteristics and formation mechanism of mine groundwater to varying degrees. The northern part of the Beiyi mining area of Gubei Coal Mine is taken as the research area in this study. Based on the data of 52 groups of limestone water (Taihui water) samples in the primary environment, in the mining stage and after grouting, the spatial and temporal variation trend of the chemical characteristics of Taihui water was studied by means of constant index mathematical statistics, a Piper diagram, total ionic salinity, correlation analysis, the ion ratio method and the saturation index. The purpose of this study is to analyze the influence of special geological structures, mining activities and grouting treatment on the formation process of the chemical characteristics of Taihui water, and to provide a basis for the identification of water inrush sources and the resource utilization of deep mine water in this area. The results show that in the three stages, the order of cation concentration is Na+ + K+ > Ca2+ > Mg2+, and the order of anion concentration is changed from Cl− > SO42− > HCO3− to Cl− > HCO3− > SO42−. The hydrochemical type is the most abundant in the mining stage, and tends to be unified after grouting. The dissolution of carbonate minerals, gypsum, rock salt and silicate minerals; cation exchange; pyrite oxidation; and the mixing of grouting precipitation liquid mainly occur in the limestone water. These effects are enhanced or weakened due to the influence of pumping and drainage and grouting precipitation liquid. The results of this study may be beneficial to the sustainable utilization of deep groundwater resources in other similar mines, and promote the establishment of data management and identification mechanisms of water inrush sources in deep coal seams.

Assessment of surface and groundwater quality in the Ctalamochita River basin, Argentina: hydrogeochemical characteristics and exploratory data analysis.

Freshwater and groundwater are important resources for the drinking water supporting agricultural and livestock activities in the Córdoba province, Argentina. The aim of this study was to assess the physicochemical and microbiological quality of surface water (n = 14) and groundwater (n = 17) sites in the middle-lower basin of the Ctalamochita River (Córdoba, Argentina) for human and animal consumption. A total of 18 physicochemical and five microbiological parameters were evaluated to determine the hydrogeological characteristics of both water resources and their suitability for human and animal consumption using the Water Quality Index (WQI). The results indicated that Na+ and HCO3- were the dominant cation and anion, respectively, in both water resources. Physicochemical and microbiological parameters values were compared with national and international guidelines. The WQI showed that groundwater samples exhibited poorer quality when compared to surface waters for human consumption, primarily due to elevated concentrations of major ions and the presence of total coliforms and Pseudomonas aeruginosa. Meanwhile, the WQI for animal consumption indicated that both surface and groundwater samples were suitable for this purpose. The Piper diagram showed that most of the surface water samples were classified as Na+-Cl--HCO3-, while groundwater samples were classified as Na+-HCO3-. This classification highlights the hydrogeochemical differences between the two water resources. TheGibbs diagram indicates that the chemical composition of both surface and groundwater sources is primarily controlled by processes of rock-water interaction and evaporation. The findings of this study will facilitate the development of a proactive plan to safeguard and sustain water resources in the middle-lower basin of the Ctalamochita River. This can be achieved through the implementation of preventive strategies and the introduction of innovative policies.

Application of Hydrochemical Parameters as Tool for Sustainable Management of Water Supply Network

Effective management of Water Supply Systems (WSSs) is crucial for ensuring safe drinking water. The WSS of Varaždin County is a complex network involving three groundwater sources: Bartolovec and Vinokovščak wellfields (alluvial aquifers) and Bela karstic spring. To achieve a comprehensive characterization of WSSs, routine laboratory data was integrated with stable isotopes and geochemical modeling. Within this study, all measured parameters remain below the Maximum Contaminant Level (MCL), ensuring water safety for human consumption. The Piper diagram identified variations in water sources based on their chemical composition, providing a simplified overview of mixing patterns within WSSs. Among the modeling approaches, inverse modeling (IM) was found to be more reliable than forward modeling (FM) and mass balance modeling (BM). Despite the limited capacity of δ18O to provide accurate mixing results, it was revealed that the reservoir water was in equilibrium with the air (no evaporation effects), indicating well-sealed reservoirs. Mixing modeling showed that the western, southwestern, and northern parts of the WSS mixed all three sources, whereas the eastern and southeastern areas primarily relied on the deeper aquifer of the Bartolovec source, indicating potential vulnerability. Strict validation criteria ensured the reliability of results, demonstrating the effectiveness and applicability of geochemical modeling in water security management plans.

Groundwater Geochemistry in the Karst-Fissure Aquifer System of the Qinglian River Basin, China

The Qinglian River plays a significant role in China’s national water conservation security patterns. To clarify the relationship between hydrogeochemical properties and groundwater quality in this karst-fissure aquifer system, drilling data, hydrochemical parameters, and δ2H and δ18O values of groundwater were analyzed. Multiple indications (Piper diagram, Gibbs diagram, Na+-normalized molar ratio diagram, chloro-alkaline index 1, mineral saturation index, and principal component analysis) were used to identify the primary sources of chemicals in the groundwater. Silicate weathering, oxidation of pyrite and chlorite, cation exchange reactions, and precipitation are the primary sources of dissolved chemicals in the igneous-fissure water. The most relevant parameters in the karst water are possibly from anthropogenic activities, and other chemicals are mostly derived from the dissolution of calcite and dolomite and cation exchange reactions. Notably, the chemical composition of the deep karst water from the karst basin is mainly influenced by the weathering of carbonate and cation exchange reactions and is less affected by human activities. The hydrogeochemical properties of groundwater in the karst hyporheic zone are influenced by the dissolution of carbonates and silicates, evaporation, and the promotion effect of dissolution of anorthite or Ca-containing minerals. Moreover, the smallest slope of the groundwater line from the karst hyporheic zone among all groundwater groups revealed that the mixing effects of evaporation, isotope exchange in water–rock interaction or deep groundwater recharge in the karst hyporheic zone are the strongest. The methods used in this study contribute to an improved understanding of the hydrogeochemical processes that occur in karst-fissure water systems and can be useful in zoning management and decision-making for groundwater resources.

Analysis of Groundwater Salinity Distribution Based on Electrical Conductivity (EC) and Hydrochemical Approaches to Deep Wells in Sayung Subdistrict, Demak Central Java

In coastal areas, obtaining groundwater is not easy due to the lack of geological support conditions that cause water in the area to have poor quality such as groundwater that becomes salty. The coastal area of Sayung Subdistrict has geomorphological conditions whose surface tends to be flat with elevations 0-5 m higher than sea level and is dominated by alluvial material so that it can cause seawater infiltration to increase. The purpose of this research was to determine the distribution of salinity of groundwater in the coastal area of Sayung Subdistrict and to determine the cause of groundwater becoming salty. The method used in this research is the electrical conductivity (DHL) approach which is then classified based on the level of saltiness of groundwater. And then, well water from the sample points was tested using a hydrochemical test with the parameters used, namely the content of cations (Na, K, Mg, Ca) and anions (Cl, CO3, HCO3, SO4, NO3). This research was conducted at 33 well points spread across Sayung sub-district. The results of this study show that the electrical conductivity value obtained is between the range of 928-7,199 μS/cm which is divided into 3 classifications namely fresh water, fresh-brackish water, and brackish water. The analysis of the Trilinier Piper diagram shows that the saltiness of the groundwater is due to indications of seawater mixing characterized by a chloride (Cl) content that is increasingly greater towards the sea.

Appraisal of groundwater suitability for drinking and irrigation utilities in the Cooum River basin, South India: Implications from uranium, nitrate, and fluoride health risks

The study reveals that 6% of groundwater samples exceed the WHO's recommended fluoride limit of 1.5 mg/L, and 15% surpass the nitrate standard of 45 mg/L, rendering the water unsuitable for drinking. Gibbs plot analysis identifies evaporation as the dominant factor affecting groundwater chemistry, while the Piper diagram classifies the water into mixed Ca–Mg–Cl and NaCl types, indicating natural processes and potential seawater intrusion. Cation exchange processes are observed in 75.5% of samples, as shown by Schoeller's indices. The hydrochemical facies evolution suggests freshening from recharge in most samples, with signs of salinity intrusion in others. Between 2010 and 2023, land use and land cover (LULC) changes show a significant increase in built-up areas, resulting in reduced groundwater recharge and heightened pollution risks. The classification accuracy is high, with an overall accuracy of 82.20% and a Kappa coefficient of 83.06%. Water Quality Index (WQI) assessment reveals that 47% of the groundwater samples are excellent for drinking, while 20.6% are suitable. Although 80% of the groundwater remains appropriate for agriculture, the study highlights the need for targeted groundwater management to address urbanization impacts and mitigate health risks from elevated nitrate ingestion, particularly for vulnerable populations such as children.

Hydrogeochemical Characteristics and Sulfate Source of Groundwater in Sangu Spring Basin, China

The Sangu Spring Basin is located in an important economic area, and groundwater is the main source of water for local life and industry. Understanding the sources of chemical components in groundwater is important for the development and utilization of groundwater. In this paper, we analyzed the origin of the chemical components of groundwater and their evolution in the Sangu Spring Basin using statistical analysis, Piper diagrams, Gibbs diagrams, ion ratios, and combined hydrochemistry–isotope analyses. The results show that the groundwater in the Sangu Spring Basin is mainly derived from atmospheric precipitation, that the groundwater in stagnant and confined environment zones was formed under colder climatic conditions, and that the surface water (SW) has a close hydraulic relation with the groundwater. Water–rock interaction is the main factor controlling the composition of groundwater. The compositions of groundwater are mainly derived from carbonate weathering, silicate weathering, and dissolution of gypsum. Na+ and K+ in groundwater mainly come from the dissolution of albite and potassium feldspar, rather than rock salt. Ion exchange occurs in karst groundwater (KGW) and fissure groundwater (FGW), and ion exchange is dominated by the exchange of Mg2+ and Ca2+ in the groundwater with Na+ and K+ in the rock or soil. Sulfate in groundwater is derived from dissolution of gypsum, infiltration of atmospheric precipitation, and leakage of SW. Groundwaters with the highest sulfate content are located in the vicinity of SW, as a result of receiving recharge from SW seepage. Groundwaters with higher sulfate contents are located in the stagnant and deeply buried zones, where sulfate is mainly derived from the dissolution of gypsum. SW seepage recharges groundwater, resulting in increased levels of Cl−, NO3− and SO42− in groundwater. These insights can provide assistance in the protection and effective management of groundwater.

Identifying groundwater characteristics and controlling factors in Jiaozhou Bay’s northern coastal region, China: a combined approach of multivariate statistics, isotope analysis, and field empirical investigations

Explicit identification of hydrochemical processes and their controlling factors within groundwater systems is critical for the sustainable utilization of water resources in coastal urban areas. This study was undertaken in the North Coastal Region of Jiaozhou Bay (NCRJB), located in the eastern part of Shandong Province, China, an area grappling with significant issues of groundwater quality degradation and water scarcity. A total of 105 groundwater samples and 34 surface water samples, collected from 2020 to 2024, were analyzed and studied using various hydrogeological tools, multivariate statistical analyses, and water quality assessment methods. These include the Piper diagram, hydrochemical facies evolution diagram (HFE-D), Principal Components Analysis (PCA), correlation analysis, stable isotope analysis, Water Quality Index (WQI), and USSL diagrams. The results indicated that all surface water and pore groundwater samples were categorized as Na-Cl type, exhibiting high Total Dissolved Solids (TDS) and Electrical Conductivity (EC) values, characteristics that render them poor to unsuitable for drinking and irrigation purposes. The fracture groundwater is predominantly of the Ca-Na-Cl mixed type, with average suitability for irrigation and a limited proportion (22.5%) deemed suitable for drinking. Seawater intrusion, primarily through the surface water system, and the impact of human activities were identified as the predominant controlling factors con-tributing to the degradation of the local groundwater environment. Field empirical investigations further validated the results derived from hydrogeological assessments, multivariate statistical analyses, and isotopic approaches. The long-term shifts in hydrochemical properties, along with the latent threat of seawater intrusion, exhibit an upward trend during the dry season and show a certain degree of mitigation during the wet season. This study highlights that field investigations, in conjunction with hydrochemical tools, multivariate statistical analyses, and stable isotope analysis, can successfully furnish reliable insights into the predominant mechanisms governing regional groundwater evolution within the context of long-term and intricate envi-ronmental settings.

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

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

Groundwater quality assessment for drinking and irrigation purposes in arid to semiarid region of Indus Basin of South Punjab, Pakistan

<p><a name="_Hlk173243332"><span style="background-color:white;color:black;font-family:"Times New Roman",serif;font-size:12.0pt;line-height:150%;">As the groundwater pollution is increasing, it is crucial to assess groundwater quality and characterize hydrogeochemistry accurately for long term water supply. </span></a><span style="background-color:white;color:black;font-family:"Times New Roman",serif;font-size:12.0pt;line-height:150%;">In this study groundwater samples were collected from 120 locations from Bahawalpur district and analyzed for electrical conductivity (EC), pH, total dissolved solids (TDS), sodium (Na<sup>+</sup>), potassium (K<sup>+</sup>), calcium (Ca<sup>2+</sup>), magnesium (Mg<sup>2+</sup>), carbonate (CO<sub>3</sub><sup>-</sup>), bicarbonate (HCO<sub>3</sub><sup>-</sup>), sulfate (SO<sub>4</sub><sup>2-</sup>), chloride (Cl<sup>-</sup>), nitrate (NO<sub>3</sub><sup>-</sup>), fluoride (F<sup>-</sup>) and heavy metals. The results obtained from the analysis of samples showed that the SAR of nearly 65% of samples collected from Bahawalpur district were in acceptable limit (<6 meq L<sup>-1</sup>), while 12% found to be unfit for irrigation (>10 meq L<sup>-1</sup>). Similarly, the RSC values depicted that 8% samples were unfit while 64% samples were falling in the category of fit irrigation water. Most of the water samples were predominantly Ca<sup>2+</sup>-HCO<sub>3</sub><sup>-</sup> and Na<sup>+</sup>-HCO<sub>3</sub><sup>-</sup> type, that were controlled by various processes of cation exchange, water-rock interaction, dissolution and evaporation. Some samples fall in the middle of diamond and lower triangles of Piper diagram are showing no dominant type of water (mixed water type) due to the complex influence of rock-water interactions as well as anthropogenic activities. The Water Quality Index (WQI) showed that out of total 120 sampling sites in Bahawalpur the number of excellent water samples were only 2% while 18% water samples were characterized as hazardous. Moreover, the number of samples falling in the categories of good, poor and very poor quality water were 36%, 29% and 13% respectively.</span></p>

Chemical Spatiotemporal Characteristics and Environmental Driving Factors of Groundwater in Hetao Irrigation Area

To explore the chemical characteristics and environmental factors of groundwater in the Hetao Irrigation Area of Inner Mongolia, five irrigation fields, including UulanBuh, Jiefangzha, Yongji, Yichang, and Wulat, were selected as the research area. From 72 groundwater observation wells, a total of 216 groundwater samples were collected throughout three typical periods： the end of freeze-thaw （March）, the middle of irrigation （July）, and the end of autumn watering （November）. Comprehensive methods were utilized, such as statistical analysis, Piper three-line diagram, Gibbs diagram, ion ratio, and principal component analysis, to explore the changes in the groundwater chemical environment and the environmental driving factors of groundwater component formation. The groundwater drinking suitability was evaluated using the water quality index （WQI）, and the irrigation suitability was analyzed using the USSL and Wilcox plots. The results indicated that the groundwater in the research areas was generally saline, and the total anion and cation concentrations in each period in ascending order were as follows： late freeze-thaw stage, late autumn irrigation stage, and mid-irrigation stage, with Na+ and Cl- being the major contributing ions. The chemical type of groundwater was dominated by Cl-Na, followed by Cl·SO4-Ca·Mg and a coexistence with SO4-Ca·Mg, HCO3·Cl-Na, HCO3-Na, and HCO3-Ca·Mg. Based on WQI values, the shallow groundwater in Hetao Irrigation District was mainly classified as Class IV and Class V, and the quality was poor in general. According to the USSL diagram and Wilcox diagram, the comprehensive evaluation results showed that the salinity and sodium concentration of shallow groundwater in the irrigation area were generally high. A total of 80.6% of the water samples during the late freeze-thaw period, 76.1% during the mid-irrigation period, and 77.6% during the late autumn irrigation period lacked irrigation suitability. Two major controlling factors of groundwater chemical characteristics were present in the study area, namely, evaporation and rock weathering, and Na+ and Cl- mainly came from the dissolution and cation exchange of salt rocks. Agricultural irrigation and drought were the chief driving factors of groundwater chemical evolution in the Hetao Irrigation Area. The study provides technical support for optimizing agricultural management measures and a theoretical reference for rational utilization of groundwater resources in the Yellow River irrigation area of Inner Mongolia.

Assessing sources of groundwater quality and health risks using graphical, multivariate, and index techniques from a part of Rajasthan, India

Groundwater provides sustainable potable water in developing countries like India. However, contaminated groundwater directly affects human health. The United Nation policy is to provide clean water for all by 2030. Therefore, groundwater samples collected from a part of Rajasthan, India were analysed for chemical parameters to identify the sources of groundwater quality variation and associated health risks. To achieve this objective, a comprehensive approach of entropy water quality index (EWQI), Piper and Gibbs diagrams, ionic ratios (IR), synthetic pollution index (SPI), principal component analysis (PCA), and non-carcinogenic health risk (NHR) methods were used. EWQI revealed that groundwater quality was not fit for drinking in 81.86% of the area due to higher TDS, Na+, , , , and contents, which was statistically significant by ANOVA test. Modified Piper’s diagram identified Ca2+ - , Ca2+ - , Na+- , and Na+ - types in 36.67%, 22.73%, 13.64%, and 27.27% of groundwater samples, respectively. Gibbs diagrams illustrated that 59.09% and 40.81% of groundwater samples fell in the rock and evaporation domains, respectively. Ionic ratios demonstrated that geogenic processes (mineral dissolution, ion exchange, and evaporation) and anthropogenic activities cause groundwater quality degradation. PCA indicated that PC1 has high loadings of TDS, Mg2+, Na+, , and , PC2 shows high loadings of pH and , and PC3 represents high loadings of , K+, and , which was further supported by t-test analysis. SPI revealed that 99.82% of the study area is polluted. NHR values (0.03 to 1.68, 0.02 to 1.29, and 0.03 to 1.30 for children, women, and men, respectively) showed that long-term exposure to and -containing drinking water poses a higher health risk to children compared to men and women. Regular water quality monitoring, sanitation facilities, limited application of agrochemicals, etc. were suggested. Such a study would aid environmental public health programs.

Multivariate Statistical Analysis and Geospatial Mapping for Assessing Irrigation Water Quality in the Aquifers of the South-Atlas Tinghir-Errachidia-Boudenib basin (Pre-African Trough, Morocco)

This study investigates the hydrogeochemical characteristics of the South-Atlas Tinghir-Errachidia-Boudenib trough situated in the arid southeastern region of Morocco. The primary objective is to assess the quality of groundwater intended for both drinking and irrigation purposes. Advanced multivariate statistical techniques such as Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) will be utilized to decipher the hydrogeochemical processes influencing groundwater mineralization. Furthermore, the research will determine the suitability of groundwater for irrigation using various indices, including Sodium Adsorption Ratio (SAR), Percent Sodium (Na%), Permeability Index (PI), and the Piper trilinear diagram.During February 2023, a systematic collection of fifty groundwater samples took place, spanning different aquifers such as those from the Senonian, Infracenomanian, Quaternary, and Paleozoic formations. These samples were subjected to thorough analysis to evaluate their quality, typology, origin, and irrigation suitability.The study's findings reveal that the majority of groundwater constituents in the South- Atlas Tinghir-Errachidia-Boudenib trough exceed the World Health Organization's (WHO) drinking water standards. The Piper diagram shows three major types of hydrogeochemical facies detected in different aquifers of the study area. The majority of the samples belonged to Ca-Mg-Cl-SO4 followed by Na-K-Cl-SO4 and Ca-Mg-HCO3. Three unique processes governing groundwater hydrochemistry were identified using multivariate techniques: The first group (which matches PC1), which consists of [EC, Na+, Cl-, TDS, TH, Mg2+, SO42-, and Ca2+], represents the mineralization axis found in the southern portion of the research area's Infracenomanian aquifer (between Aoufous and Erfoud) and the Goulmima region in the south. Al, K+, and pH are found in the second group (matches PC2), which is situated in the southern portion of the research area on the Paleozoic aquifer. Some samples are also found on the Senonian aquifer in the eastern Boudnib region. The third group (PC3 matches) is made up of [HCO3- and Fe2+], and it is mostly found in the Senonian aquifer in the northeastern region of the study area (Boudenib and its surroundings). The Senonian samples demonstrated excellent SAR, Na%, and PI, values, whereas most groundwater samples from other aquifers showed good to permissible suitability for irrigation. Furthermore, the water-rock interactions and agricultural fertilizers were highlighted as key factors influencing groundwater compositions.

GROUNDWATER POLLUTION SOURCE USING PRINCIPAL COMPONENT ANALYSIS IN GUELMA PLAIN, NORTHEAST ALGERIA

This study was conducted in the agricultural region of Guelma, located in northeastern Algeria, where groundwater is the main source of water for human consumption, agriculture, and industry. The objective was to characterize groundwater quality and identify potential pollution sources using multivariate statistical methods, including Principal Component Analysis (PCA), correlation matrix, and the Piper diagram. The analyses revealed strong correlations between certain ions, such as sodium and chloride, suggesting carbonate dissolution processes, such as calcite and dolomite, leading to increased water hardness. The Piper diagram allowed for the classification of water types based on the relative concentrations of major cations (Ca²⁺, Mg²⁺, Na⁺+K⁺) and anions (Cl⁻, SO₄²⁻, CO₃²⁻+HCO₃⁻), showing a predominance of mixed hydrochemical types influenced by both natural and anthropogenic processes.PCA then simplified the interpretation by identifying the most influential variables that could serve as key indicators for the continuous monitoring of water quality. Overall, the results indicate that groundwater chemistry in this region is strongly influenced by human activities and local geological conditions, highlighting the need for sustainable management and continuous monitoring to protect this vital resource.

Groundwater quality assessment using revised classical diagrams and compositional data analysis (CoDa): Case study of Wadi Ranyah, Saudi Arabia

This research aims to assess the status and chemical properties of groundwater in the shallow aquifer of the Wadi Ranyah region, Saudi Arabia, using robust statistical methods (CoDA) that take into account the unique characteristics of chemical analysis data from forty-five (45) groundwater samples collected in the Wadi Ranyah valley. A centered logarithmic transformation (clr) approach and isometric logarithmic transformation (ilr) plots for compositional data were utilized to determine the different water types and to understand the hydrogeochemical processes influencing groundwater chemistry in the region. The results of principal component analysis and K-means clustering reveal the existence of three groundwater groupings: (i) The first group occupies the recharge region with a relationship between trace metal elements (F, Pb, Mn, Zn), pH, and TDS, indicating the effect of alteration of igneous and metamorphic rock minerals. (ii) The second group characterizes the downstream part of the Al-Hujrah area with a relationship between calcium and nitrates, indicating the influence of agricultural activities. (iii) The third group, located in the Ranyah area, shows a relationship between major ions (Na+, SO42−, Mg2+, HCO3–, Cl−, K+), which explains water mineralization influenced by silicate weathering and evaporation phenomena. According to the modified Piper diagram (ilr Piper), two hydrochemical facies are identified. The upstream region is categorized as Ca-HCO3– while the downstream region is classified as Na-K-HCO3–. Calculated water quality index (WQI) values indicate that all Wadi Ranyah groundwater samples are of very poor quality (WQI > 300). This is due to higher concentrations of polluting elements (Pb, Mn and F), in particular the high lead concentrations which vary between 0.24 and 0.4 mg/L, and are well above the WHO limit (0.01 mg/L) for consumption of drinking water. The application of CoDA for the first time in the study region has provided a more detailed and reliable assessment of the mechanisms governing groundwater quality, permitting suggestions for the management of groundwater resources and defining future research needs.

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.

Hydrochemical insights, water quality, and human health risk assessment of groundwater in a coastal area of southeastern China.

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca2+> Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > NO3- > F- during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO3-Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water-rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO3- and SO42- were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection.

Effect of CO2 and H2SO4 on the dissolution of a carbonate basement and alteration of silicates in a volcano-sedimentary system in central Mexico

This study explores the hydrogeochemical and isotopic characteristics of groundwater in the Irapuato Valley and Celaya Valley Aquifers in central Mexico, specifically focusing on the role of CO2 in mineral alteration during water-rock interaction. The study is grounded in the principles of hydrogeochemistry and stable isotope geochemistry, analyzing the impact of CO2 and H2SO4 on the weathering of carbonates and silicates. Hydrogeochemical analysis, including Piper diagrams, and isotopic measurements (δ13C, δ18O, δ2H), were conducted on water samples from wells in four municipalities (Irapuato, Salamanca, Villagrán, and Juventino Rosas). The data was statistically evaluated using Shapiro-Wilk tests to assess normality, skewness, and kurtosis, ensuring the reliability of the findings. The results indicate that HCO3− dominates the groundwater composition, with CO2 and H2SO4 significantly influencing mineral alteration processes. The isotopic data suggest that CO2 is primarily released from carbonate rock degassing, with slight isotopic enrichment in δ13C due to water-carbonate interaction. Hydrothermal fluids contribute to the geochemical evolution of the aquifer, leading to the formation of minerals such as tridymite, alunite, and kaolinite. Additionally, some groundwater samples exhibit evidence of thermalism and water-rock interactions, influencing their isotopic signatures and temperatures. These findings underscore the importance of CO2 in groundwater chemistry and highlight the need for further studies to understand regional flow dynamics and the potential impact of geothermal systems on water quality.

Integrating GEE and IWQI for sustainable irrigation: A geospatial water quality assessment

The surface and sub-surface water quality is one of the decisive parameters for sustainable agriculture and water resources management. Deteriorating water quality impacts the irrigation, crop production, and human health. Therefore, the present work made an attempt to identify the water suitability for irrigation using the contemporary approach i.e. Irrigation Water Quality Index (IWQI) and Zone mapping using GIS techniques, and demonstrated for case of Wadhwan, Gujarat India. Three indices i.e., NDVI, NDWI, and LSWI were mapped using Landsat satellite imagery, whereas, Watermask index was mapped using Sentinel II satellite imagery for the assessment of the availability of water in different forms. The IWQI has applied to categorize the water quality as severe, high, moderate, low, and no restriction. The IWQI in the study area ranges from 6.4 to 62.5. The overall the water quality of study area shows that the 13.64 % of the region in severe restriction range, 56.82% in high restriction range, and 29.54% in moderate restriction range, which is in alarming for farmers and policy makers. The GIS zoning map effectively visualized the spatial distribution of IWQI, helping decision-makers to identify severity zones. Furthermore, the Piper diagram analysis has been performed, which shows that the water quality of the study area falls under mixed Ca2+-Mg2+-Cl-, mixed Ca2+-Na+-HCO3-, and Na-HCO3 types. The results revealed that major areas are in moderate to severe restriction zones, lying under deteriorated water quality, and need immediate attention for improvement before use. The IWQI advances SDG 2 (Zero Hunger) by optimizing water quality for crop production and SDG 6 (Clean Water and Sanitation) by ensuring sustainable water resource management, while indirectly supporting SDG 15 (Life on Land) through improved soil health and land management practices.

Comprehending Spatial Distribution and Controlling Mechanisms of Groundwater in Topical Coastal Aquifers of Southern China Based on Hydrochemical Evaluations

Groundwater quality and availability in coastal aquifers have become a serious concern in recent times due to increased abstraction for domestic, agricultural and industrial purposes. (1) Background: Zhuhai city is selected as a representative coastal aquifer in Southern China to comprehensively evaluate the hydrochemical characteristics, spatial distribution and controlling mechanisms of groundwater. (2) Methods: A detailed study utilizing statistical analyses, a Piper diagram, Gibbs plots, and ion ratios was conducted on 114 surface water samples and 211 groundwater samples. (3) Results: The findings indicate that the pH of most groundwater is from 6.06 to 6.52, indicating a weakly acidic environment. The pH of surface water ranges from 5.35 to 9.86, with most values being weakly alkaline. The acidity in the groundwater may be related to the acidic atmospheric precipitation, an acidic unsaturated zone, oxidation of sulphide minerals and tidal action. The groundwater chemical types are predominantly mixed, followed by Ca-Mg-HCO3 type. Surface water samples are predominantly Na-Cl-SO4 type. The NO3− concentration in groundwater is relatively high, with a mean value of 17.46 mg/L. The NO2− and NH4+ concentrations in groundwater are relatively low, with mean values of 0.46 mg/L and 7.58 mg/L. (4) Conclusions: The spatial distribution of the principal chemical constituents in the groundwater is related to the landform. The chemical characteristics of groundwater in the study area are mainly controlled by the weathering and dissolution of silicate and sulfate minerals, evaporation, seawater mixing and cation exchange. Nitrate in clastic fissure groundwater, granite fissure groundwater and unconfined pore groundwater primarily originates from atmospheric precipitation, agricultural activities of slope farmland and forest land. Nitrate in confined pore groundwater and karst groundwater primarily originates from domestic sewage and mariculture wastewater. Our findings elucidate the processes characterizing the hydrogeology and surface water interactions in Zhuhai City’s coastal system, which are relevant to other catchments with similar geological characteristics.