Hydrogeochemistry of the Sarada river basin,Visakhapatnam district,Andhra Pradesh,India

Systematic hydrogeochemical survey has been carried out for understanding the sources of dissolved ions in the groundwaters of the area occupied by Sarada river basin, Visakhapatnam district, Andhra Pradesh, India. Khondalites, charnockites and granite gneisses and calc-granulites of Precambrians and alluvial deposits of Quaternaries underlie the study area. Groundwaters are both fresh and brackish; the latter waters being a dominant. Most groundwaters are characterized by Na⁺:HCO₃⁻ facies due to chemical weathering of the rocks. Enrichment of Na⁺, K⁺, Cl⁻, SO₄²⁻, NO₃⁻ and F⁻ in some groundwater samples is caused by seawater intrusion, locally accompanied by ion-exchange, and anthropogenic activities, resulting in an increase of brackish in the groundwaters. Based on the results of this hydrogeochemical study, suitable management measures are recommended to solve the water quality problems.     

Preliminary groundwater quality assessment in the central region of Ghana

Insufficient knowledge of the hydrogeochemistry of aquifers in the Central Region of Ghana has necessitated a preliminary water quality assessment in some parts of the region. Major and minor ions, and trace metal compositions of groundwater have been studied with the aim of evaluating hydrogeochemical processes that are likely to impair the quality of water in the study area. The results show that groundwater in the area is weakly acidic with mean acidity being 5.83 pH units. The dominant cation in the area is Na, followed by K, Ca, and Mg, and the dominant anion is Cl^?, followed by HCO₃ ^? and SO₄ ^2?. Two major hydrochemical facies have been identified as Na–Cl and Na–HCO_3, water types. Multivariate statistical techniques such as cluster analysis (CA) and factor analysis/principal component analysis (PCA), in R mode, were employed to examine the chemical compositions of groundwater and to identify factors that influenced each. Q-mode CA analysis resulted in two distinct water types as established by the hydrochemical facies. Cluster 1 waters contain predominantly Na–Cl. Cluster 2 waters contain Na–HCO₃ and Na–Cl. Cluster 2 waters are fresher and of good quality than cluster 1. Factor analysis yielded five significant factors, explaining 86.56% of the total variance. PC1 explains 41.95% of the variance and is contributed by temperature, electrical conductivity, TDS, turbidity, SO₄ ^2?, Cl^?, Na, K, Ca, Mg, and Mn and influenced by geochemical processes such as weathering, mineral dissolution, cation exchange, and oxidation–reduction reactions. PC2 explains 16.43% of the total variance and is characterized by high positive loadings of pH and HCO₃ ^?. This results from biogenic activities taking place to generate gaseous carbon dioxide that reacts with infiltrating water to generate HCO₃ ^?, which intend affect the pH. PC3 explains 11.17% of the total variance and is negatively loaded on PO₄ ^3? and NO₃ ^? indicating anthropogenic influence. The R-mode PCA, supported by R-mode CA, have revealed hydrogeochemical processes as the major sources of ions in the groundwater. Factor score plot revealed a possible flow direction from the northern sections of the study area, marked by higher topography, to the south. Compositional relations confirmed the predominant geochemical process responsible for the various ions in the groundwater as mineral dissolution and thus agree with the multivariate analysis.     

Groundwater quality in the lower Varuna River basin,Varanasi district,Uttar Pradesh

The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting of clay, silt, sand and gravel of various grades. The hydrogeochemical study was undertaken by randomly collecting 75 groundwater samples from dug wells and hand pumps covering the entire basin in order to understand the sources of dissolved ions, and to assess the chemical quality of the groundwater through analysis of major ions. Based on the total dissolved solids, two groundwater samples are considered unsuitable for drinking purpose, but all samples are useful for irrigation. Graphical treatment of major ion chemistry by Piper diagram helps in identifying hydro-geochemical facies of groundwaters and the dominant hydrochemical facies is Ca-Mg-HCO₃ with appreciable percentage of the water having mixed facies. As per Wilcox’s diagram and US Salinity laboratory classification, most of the groundwater samples are suitable for irrigation except two samples (No’s 30 and 68) which are unsuitable due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on residual sodium carbonate, have revealed that all groundwaters are in general safe for irrigation except one sample (No. 27), which needs treatment before use. Permeability index indicates that the groundwater samples are suitable for irrigation purpose. Although the general quality of groundwater of the lower Varuna River basin is suitable for irrigation purpose, fifty seven percent of the samples are found having nitrate content more than permissible limit (>45 mg/l) which is not good for human consumption. Application of N-Fertilizers on agricultural land as crop nutrients along the Varuna River course may be responsible for nitrate pollution in the groundwater due to leaching by applied irrigation water. The other potential sources of high nitrate concentration in extreme northern, southern and southwestern parts of study area are poor sewerage and drainage facilities, leakage of human excreta from very old septic tanks, and sanitary landfills. The high fluoride contamination (>1.5 mg/l) in some of the samples may be due to the dissolution of micaceous content in the alluvium. Nitrate and fluoride contamination of groundwater is a serious problem for its domestic use. Hence an immediate protective measure must be put into action in the study area.     

Numerical analysis of hydrogeochemical data: a case study (Alto Guadalentı́n,southeast Spain)

This study examines the spatial variability of the factors obtained from the application of correspondence analysis to a hydrogeochemical data set. The goal was to synthesize the hydrogeochemical information using this multivariate statistical technique, by setting a series of factors which clarified the main properties of one aquifer. Then, a geostatistical framework to obtain a probabilistic assessment of groundwater quality was established. Experimental and theoretical semivariograms of the selected factors, considered as regionalized variables, were computed. These variographic information and factor values in the experimental sites were used in the ordinary kriging, which provides unbiased and linear estimates of the regionalized variables. These estimates were used to compile maps of the chosen factors, which explain their spatial distribution.The selected case study was the alluvial aquifer of Alto Guadalentı́n which is situated in southeast Spain, in the Internal Zones of Betic Cordilleras. These waters are chiefly SO₄ and Cl types, but HCO₃ facies are common in the central sector of the basin. High temperature, acid pH, problems of overexploitation and pollution by CO₂-gas characterise these waters. Available groundwater quality monitoring data were used to calibrate the numerical model. The present study focused on setting the main physical and chemical attributes and establishing the spatial pattern of groundwater quality and the temporal changes in this pattern.     

Thermal and mineral waters in north-eastern Slovenia

 The Mura basin in north-eastern Slovenia is made up of two depressions, developed during the Late Neogene and Early Pliocene all within a widespread system of Pannonian basins. Both depressions are characterized by the occurrence of thermal waters of somewhat different hydrogeochemical character. Radgona depression is in the northern part of the basin and reaches depths of about 2 km. Thermal waters are generally dominated by sodium-bicarbonate, not related to the age of an aquifer, its wallrock composition, the type of porosity or total concentration of dissolved solids. Locally, sulphate-rich waters are encountered, and they are related to the presence of gypsum in the rocks of pre-Tertiary basement. The adjacent Ljutomer depression is over 4 km deep and comprises compartments with stagnant or semi-stagnant aquifers. Herein saline waters predominate, even in the aquifers of carbonate composition and abundant CO₂ gas. In shallower, unconsolidated, intergranular aquifers sodium-bicarbonate waters predominate. Thermal aquifers of this type are very important to the economy of the region, but they are also subjected to overexploitation which is reflected in time-dependent changes of dynamic pressures, temperature, conductance, salinity, pH and concentration of major ions, trace elements, dissolved gasses, and total organic carbon. Mineral waters occur in shallow aquifers or springs in marginal areas of the Radgona depression. Bicarbonate waters are dominated by calcium, or both calcium and sodium. Some mineral waters are formed mainly by penetration of CO₂ gas into shallow aquifers and consequent water–rock interaction. Composition of some mineral waters indicate their possible evolution from thermal waters which have risen from central parts of the Radgona depression along deep-seated faults, and have been modified by cooling and mixing processes. Received: 30 November 1998 · Accepted: 22 March 1999     

Geochemistry of natural and contaminated subsurface waters in fissured bed rocks of the Lake Karachai area, Southern Urals, Russia

Hydrogeochemical investigations of natural and contaminated subsurface waters were conducted between 1992–94 in an area where liquid radioactive waste (RAW) was impounded in a small lake, and subsequently leaked into an underlying water bearing horizon. The waste was discharged from the radiochemical plant of the Mayak Amalgamated Industry near Chelyabinsk, Russia. The underlying water-bearing horizon in fissured metavolcanic rocks was penetrated by uncased observation wells in order to log the hydrogeochemistry. Logging was carried out using a specially designed hydrogeochemical probe, which contained 8 channels to measure continuously the temperature, pressure, electric conductivity, pH, Eh, the dissolved O₂ concentration, and the activities of Na, and NO₃ in the wells. The logging technique enabled the natural hydrogeochemical setting to be characterized and permitted delineation of bodies of contaminated waters of different origins using measurements of pH, pNa and pNO₃. The technique also permitted an evaluation of variations in the chemical composition of the RAW solutions due to radiolytic processes and to chemical interactions with the geologic medium. A conceptual model is proposed for the chemical evolution of the migrating contaminated subsurface waters in the area investigated.     

Assessment of water quality and pollution of the Lake Seyfe basin, Kırşehir, Turkey

Lake Seyfe is located in a closed basin near K?r?ehir in the central Anatolian region, Turkey. The aim of this study is to evaluate the groundwater quality and effects of lithogenic contamination carried out in the Lake Seyfe basin, which is represented by various lithologies and groundwater types. Seyfe, Horla and Akp?nar springs are recharged through marbles at the western and southwestern of the basin are ultimately and discharged into the K?z?l?rmak Formation and Lake Seyfe. The waters of deep wells drilled into the marbles are of bicarbonate type (type I) in the Ca²⁺–Mg²⁺–HCO₃ ^? and Ca²⁺–HCO₃ ^? facies. Özlühüyük spring and waters from most of trenches and shallow wells, which are fed by the K?z?l?rmak Formation, have a mixed (type II) composition in the Ca²⁺–Mg²⁺–HCO₃ ^?–Cl^? facies. Groundwater in the alluvium and K?z?l?rmak Formation along Lake Seyfe has a salty (type III) character in the Na⁺–Cl^? facies. The main reasons of formation and change of the groundwater salinity and hydrochemical facies in the Seyfe basin are causing the various (a) lithogenic pollution and heterogeneity of the K?z?l?rmak Formation, (b) salinity of the upper soil zones, and (c) evaporation of the trench and channel waters open to the atmosphere. Considering parameters such as sodium hazard, specific conductivity, bicarbonate and carbonate hazards, waters in the study area are generally suitable for agricultural usage.     

Hydrogeochemistry of groundwater and anthropogenic control over dolomitization reactions in alluvial sediments of the Deoria district: Ganga plain,India

Groundwater is a critical resource in Deoria district, as it is the main source of drinking water and irrigation. The aquifer has deteriorated to a high degree, during the last two to three decades, in quality and quantity due to high population growth and environmental pollution. More than 90% of the population get their drinking water from subsurface waters. Fifteen wells were sampled in June 2006 to probe the hydrogeochemical components that influence the water quality. The results show that groundwater have EC, TDS, Na⁺, Mg²⁺, HCO₃⁻ and TH higher than the WHO, 1997 maximum desirable limits. A hydrogeochemical numerical model for carbonate minerals was constructed using the PHREEQC package. The regression analysis shows that there are three groups of elements which are significantly and positively correlated. The main hydrochemical facies of the aquifer (Ca + Mg–HCO₃) represents 33.33% of the total wells. The geochemical modeling demonstrated that the reactions responsible for the hydrochemical evolution in the area fall into three categories: (1) dissolution of salts, (2) precipitation of dolomite, (3) ion exchange. Solubility of dolomite, calcite, aragonite and gypsum were assessed in terms of the saturation index. The thermodynamic prerequisites for dolomite supersaturation reactions are satisfied by subsurface waters, since they are supersaturated with respect to dolomite, undersaturated (or in equilibrium) with respect to calcite, and undersaturated with respect to gypsum. The Ca²⁺ versus SO₄²⁻ and Mg²⁺ versus SO₄²⁻ trends are also compatible with homologous trends resulting from dolomite supersaturation.     

Geochemical assessment,mixing behavior and environmental impact of thermal waters in the Guelma geothermal system,Algeria

A study of thirteen geothermal springs located in the geothermal field of Guelma, northeastern Algeria, was conducted. Samples were collected during the period between January 2014 and February 2016. Geochemical processes responsible for the chemical composition of thermal and mineralized water were evaluated. The hydrochemical analysis shows that the thermal waters are characterized by the presence of two different chemical facies, the first type SO₄–Ca in the east, west and south of Guelma, the second type HCO₃–Ca in the south. This analysis also attributed to sodium, chlorides, and sulfates to an evaporitic terrigenous origin by the molar ratio Sr²⁺/Ca²⁺. The thermal spring waters from Guelma geothermal system have a meteoric origin, and all samples are immature with strong mixing between hot and shallow waters with 19–38.5% rate of mixing. The silica geothermometer shows that these thermal waters have a temperature varying from 84 to 122 °C and that the water came from a depth of 2100–3000 m through a fault system that limits the pull-apart basin of Guelma. Potential environmental effluent from thermal spas could pollute in both the irrigation and drinking waters, and which imposes danger on the health of the inhabitants of the region.

     

Hydrogeochemical processes in an arid region of Europe (Almeria,SE Spain)

In the Lower Andarax river basin 3 aquifer units have been defined, namely the Carbonate Aquifer, the Deep Aquifer and the Detrital Aquifer, which between them contain a wide variety of water types. Identification of hydrogeochemical processes has been performed by studying a series of ionic ratios, comprising the principal constituents together with B and Li (Cl vs SO₄, Cl vs Mg, Cl vs Li, B vs Li). Among the processes detected, the circulation of groundwaters with high concentrations of SO₄ was found to have significant effects. Moreover, in the coastal region, naturally occurring processes related to the flushing of saline waters from sediments of marine origin occur in conjunction with others, clearly of human origin, that are related to saltwater intrusion. A further factor is the entry, from overlying deposits, of waters with a high saline content; this salinity is related to the flushing of sediments of marine origin. The use of B and Li together enables waters in which salinity is related to seawater to be distinguished from others in which salinity is related to evaporitic layers or to thermal areas. The concentration of Li is directly related to water temperature, while that of B is greater in the most saline sectors, of gypsiferous and/or seawater origin.     

Chemical and isotopic examination of produced waters from the BP-Wolf lake in situ combustion pilot

The chemical and isotopic compositions of co-produced waters can be used to monitor the processes that take place during in situ combustion. Anticipated processes include mixing of waters, production of CO₂, production of high concentrations of dissolved sulphate and variations in water chemistry associated with heated zones. Water sources include pore waters in oil-bearing strata, waters in overlying or underlying aquifers, water condensed from previously injected steam, and waters associated with combustion. Waters from all sources may mix during production and interpretation of the combustion process can be refined by an understanding of water sources. Produced fluids from the BP-Wolf Lake pilot site in Alberta have been examined to evaluate the effectiveness of the chemical composition of water and the isotopic compositions of aqueous species for monitoring in situ combustion.Produced waters do not show simple conservative mixing behaviour. This suggests that multiple sources of water and other processes, including water-rock reactions, act to modify water compositions. At least three sources of produced waters can be recognized and these are interpreted to be formation water, injected steam and waters that have low Cl and high HCO₃ due to combustion. It is not possible to distinguish waters in the oil-bearing formation from regional waters present in aquifers that underlie the stimulated intervals. Dissolved aqueous species, such as SiO₂, Na, K (as Na/K) and Cl can be used to monitor the approach of the combustion front. Sulphate has been suggested as an indicator of approaching combustion and, although sulphate concentrations rise as combustion approaches a producing well, this indicator is not reliable in all cases. The use of all the above chemical parameters is recommended for detection of combustion zones during operation.The isotope composition of produced waters confirms that there has been significant water-rock interaction during combustion. Carbon isotope compositions of HCO₃ that range from −8 to −25% δ¹³C show that oil oxidation is a major contributor of CO₂ at high temperatures, but CO₂ produced by carbonate mineral dissolution becomes more significant as temperature decreases. Sulphate concentrations in waters produced during combustion can be an order of magnitude higher than those observed during steam stimulation. Both the oil (bitumen) and pyrite (FeS₂) are significant sulphur sources. Typically, the sulphur in both phases is in a reduced state and is available through oxidation associated with combustion. The δ³⁴S of dissolved sulphate in produced waters does not unequivocally identify either of the two major sources of sulphur. However, the relatively depleted δ³⁴ values for SO₄ suggest that the high sulphate concentrations generally associated with the approach of the combustion front result from the oxidation of pyrite.     

Chemical characteristics of groundwater in parts of the Gambhir River basin,Bharatpur District,Rajasthan, India

Twenty-nine dug well samples have been collected from the Gambhir River basin in the Bharatpur District of Rajasthan State in India for hydrogeochemical study to understand the sources of dissolved ions and assess the chemical quality of the water. Broadly speaking, the groundwaters have a chemical composition within the permissible limits suggested for drinking water. Nitrate is higher than the acceptable limit in some samples, due to the use of fertilizers. Graphical treatment of the major ion chemistry helps in deciphering the chemical characteristics of groundwaters, which may then be used for grouping the samples to identify the trends of the chemical alteration of the meteoric water. Four groups have been identified in the Gambhir River basin groundwater system: (1) HCO ₃ enriched, (2) mixed type, (3) alkali-rich, high TDS type, and (4) HCO ₃ deficient. Possible aqueous species have been identified for these four groups of samples. In groups I and II, the species are Ca (HCO ₃) ₂, Mg (HCO ₃) ₂, NaCl, Na ₂SO ₄ and NaHCO ₃. Group III, in addition to these species, has abundance of KCl. Group IV has Ca (HCO ₃) ₂, NaCl, CaSO ₄, and rather rare species such as CaCl ₂, MgCl ₂ and MgSO ₄. Interpretation of the data reveals that feldspar and pyrite weathering reactions do not play a significant role in giving groundwaters their observed chemical characteristics. Groups I and II samples have evidently been derived by dissolution of surface salts, whereas groups III and IV groundwaters suggest dissolution of a marine evaporite sequence similar to the one known to exist to the west of the study area, unconformably overlying the rocks of the Delhi Super Group. There are indications that joints play an important role in segregating groundwaters with different chemical characteristics.     

Hydrogeochemical processes and quality assessment of groundwater in Dumka and Jamtara districts, Jharkhand, India

The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, anions (F^?, Cl^?, NO₃ ^?, HCO₃ ^?, SO₄ ^2?) and cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). The analytical results show the faintly alkaline nature of water and dominance of Mg²⁺ and Ca²⁺ in cationic and HCO₃ ^? and Cl^? in anionic abundance. The concentrations of alkaline earth metals (Ca²⁺?+?Mg²⁺) exceed the alkali metals (Na⁺?+?K⁺) and HCO₃ ^? dominates over SO₄ ^2??+?Cl^? concentrations in the majority of the groundwater samples. Ca?CMg?CHCO₃ is the dominant hydrogeochemical facies in 60?% of the groundwater samples, while 33?% samples occur as a mixed chemical character of Ca?CMg?CCl hydrogeochemical facies. The water chemistry is largely controlled by rock weathering and ion exchange processes with secondary contribution from anthropogenic sources. The inter-elemental correlations and factor and cluster analysis of hydro-geochemical database suggest combined influence of carbonate and silicate weathering on solute acquisition processes. For quality assessment, analyzed parameter values were compared with Indian and WHO water quality standards. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. Total hardness and concentrations of TDS, Cl^?, NO₃ ^? _, Ca²⁺ and Mg²⁺ exceed the desirable limits at a few sites, however, except NO₃ ^? all these values were below the highest permissible limits. The calculated parameters such as sodium adsorption ratio, percent sodium (%Na) and residual sodium carbonate revealed excellent to good quality of groundwater for agricultural purposes, except at few sites where salinity and magnesium hazard (MH) values exceeds the prescribed limits and demands special management.     

Using non-conservative tracers to characterise karstification processes in the Merinos-Colorado-Carrasco carbonate aquifer system (southern Spain)

The systematic sampling of the chemical composition of the groundwater from five karst springs (including an overflow spring) and one outflowing borehole have permitted to determine distinctive chemical changes in the waters that reflect the geochemical processes occurring in a carbonate aquifer system from southern Spain. The analysis of the dissolution parameters revealed that geochemical evolution of the karst waters basically depends on the availability of the minerals forming aquifer rocks and the residence time within the aquifers. In the three proposed scenarios in the aquifers, which include the preferential flow routines, the more important geochemical processes taking place during the groundwater flow from the recharge to the discharge zones are: CO₂ dissolution and exsolution (outgassing), calcite net dissolution, calcite and dolomite sequential dissolution, gypsum/anhydrite and halite dissolution, de-dolomitization and calcite precipitation. A detailed analysis of the hydrochemical data set, saturation indices of the minerals and partial pressure of CO₂ in the waters joined to the application of geochemical modelling methods allowed the elaboration of a hydrogeochemical model of the studied aquifers. The developed approach contributes to a better understanding of the karstification processes and the hydrogeological functioning of carbonate aquifers, the latter being a crucial aspect for the suitable management of the water resources.     

Geochemical characterization of the Biga Peninsula thermal waters (NW Turkey)

Thermal water chemistry from the Biga Peninsula (NW Turkey) was investigated in order to discriminate among hydrochemical facies, and isotopic groups and identify the major geochemical processes. A systematic hydrogeochemical survey was carried out, incorporating new data as well as results from the previous studies. Results were used to further develop hydrogeological and geochemical models. Thermal water compositions were classified into four groups and the processes affecting evolution of water compositions were interpreted. Types 1, 2 and 3 are representatives of water corresponding to sulfate dominant fluids (mainly NaSO₄-type), chloride dominant fluids (mainly NaCl-type), and bicarbonate dominant fluids (Na- or CaHCO₃-type), respectively. Group 4 comprises the fluids with compositions that are not dominated by any distinctive anion. Groundwater infiltrates and circulates through the marbles of the Paleozoic basement. The isotopic composition of thermal waters revealed that deep infiltration of meteoric water took place in periods of changed climatic conditions.     

Hydrogeochemical characterization and groundwater quality assessment in the intensive agricultural zone of the Upper Cheliff plain,Algeria

The alluvial aquifer of Upper Cheliff (northern Algeria) is known for its intensive agricultural activities, which is based especially on groundwater exploitation. This aquifer is now facing a dual problem of quantity and quality, with a decrease in the groundwater levels and an increase in mineralization. Twenty monitoring samples were collected and analyzed for major ion during the dry season 2014. In the present study, we try to characterize the hydrogeochemical processes and to assess the impact of natural and anthropogenic conditions on groundwater mineralization. The analytical results of the dry season 2014 show a groundwater quality slightly alkaline (pH > 7) and indicate that the majority of samples have a values exceeding the limits of potability fixed by WHO in 2008, due to the various sources of anthropogenic pollution. The Piper diagram shows the dominance of groundwater types: Ca–Cl, the mixed facies (Cl–SO₄–Ca–Mg), and Ca–HCO₃: The mineralization process in this aquifer is mainly controlled by the lithology of the aquifer (exchange water–rock and weathering of calcareous crust dissolution in the unsaturated zone), by anthropogenic factors (discharges of untreated urban sewage, intensive use of fertilizers in agriculture and the use of domestic septic tanks by rural inhabitants) and also by geoclimatic conditions (semiarid climate). Suitability of groundwater shows more than 80% of samples have very poor quality for drinking and more than 20% of samples indicate a quality unsuitable for irrigation.     

Interaction between shallow and deep aquifers in the Tivoli Plain (Central Italy) enhanced by groundwater extraction: A multi-isotope approach and geochemical modeling

In the Tivoli Plain (Rome, Central Italy) the interaction between shallow and deep groundwater flow systems enhanced by groundwater extraction has been investigated using isotopic and chemical tracers. A conceptual model of the groundwater flowpaths has been developed and verified by geochemical modeling. A combined hydrogeochemical and isotopic investigation using ion relationships such as DIC/Cl⁻, Ca/(Ca + Mg)/SO₄/(SO₄ + HCO₃), and environmental isotopes (δ¹⁸O, δ²H, ⁸⁷Sr/⁸⁶Sr, δ³⁴S and δ¹³C) was carried out in order to determine the sources of recharge of the aquifer, the origin of solutes and the mixing processes in groundwater of Tivoli Plain. Multivariate statistical methods such as principal component analysis and Cluster analyses have confirmed the existence of different geochemical facies and the role of mixing in the chemical composition of the groundwater.     

Investigating water quality and arsenic contamination in drinking water resources in the Tavşanlı District (Kütahya,Western Turkey)

Arsenic is a natural component of the earth’s crust, and it is transported into surface water and groundwater through the dissolution of rocks, minerals and ores. In addition, arsenic leaching processes contaminate water sources and this geogenic arsenic contamination causes significant water quality problems in many parts of the world. In this study, water quality, arsenic contamination and human health risks of drinking water resources in the Tav?anl? District were determined and the origins were discussed. For this purpose, geological and hydrogeological properties were investigated. In situ measurements and chemical analyses were carried out on water samples taken from drinking water sources such as wells, springs and surface waters for hydrogeochemical studies. According to the obtained results, water resources are Ca–Mg–HCO₃, Mg–HCO₃ and Na–HCO₃ type. Total As (As_T) concentration of the water samples sometimes exceeds the permissible limit given by the TSI-266 (Standards for drinking waters, Turkish Standards Institution, Ankara, 2005) and WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2008) for drinking water. H₃AsO ₃ ⁰ and HAsO₄ ^2? are dominant arsenic species in groundwater and surface water, respectively. Typically high total arsenic concentrations can be found in regions characterized by magmatic rocks. In addition, As concentrations in surface waters were found to be higher than in groundwater in the region, due to the anthropogenic influence of mining activities in the region.