Hydrogeochemical Characterization Research Articles

Hydrogeophysical Delineation and Hydrogeochemical Characterization of the Aquifer Systems in Umuahia-South Area, Southern Nigeria

Hydrogeophysical Delineation and Hydrogeochemical Characterization of the Aquifer Systems in Umuahia-South Area, Southern Nigeria

The hydrogeochemical characterization of groundwater in Gafsa-Sidi Boubaker region (Southwestern Tunisia)

Gafsa region is one of the most productive artesian basins in Southern Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. Proper understanding of the geochemical evolution of groundwater is important for sustainable development of water resources in this region. A hydrogeochemical survey was conducted on the Plio-Quaternary shallow and on the Complex Terminal aquifers system using major (Ca, Mg, Na, SO4, Cl, NO3 and HCO3) and minor (Sr) elements, in order to evaluate the groundwater chemistry patterns and the main mineralization processes occurring in this system. Hydrochemical and isotopic data were used in conjunction with hydrogeological characteristics to investigate the groundwater composition in these aquifers. It has been demonstrated that groundwaters acquire their mineralization principally by water–rock interaction, i.e. dissolution of evaporites (halite/gypsum, pyrite, etc.) and return flow of irrigation waters, and by anthropogenic activities due to the use of nitrogen (N) fertilizers–pesticides in agriculture. The isotopic study of “stable isotopes, radiocarbon and tritium” (Yermani 2002) shows that a paleoclimatic recharge is corroborated by the relatively low carbon-14 activities (5–25.3%) of the referred groundwater group samples, which were interpreted as recharge occurring during the late Pleistocene and the early Holocene periods. The water feedings of these aquifers are mainly provided by infiltration of precipitations, infiltration of irrigation water, lateral feeding from Cretaceous relieves from the South and the North and along recent and fossil drainage networks that constitute major freshwater sources in groundwater tables (Hamed et al., J Environ Protect 1:466–474, 2010a).

Hydrogeochemical characterization of contaminated groundwater in Patancheru industrial area, southern India

The groundwater is one of the most contaminated natural resources in Patancheru industrial area due to unplanned and haphazard industrial growth and urbanization without following basic pollution control norms. The rapid industrialization initiated in early 1970 has started showing up its after effects few years later in the form of physiochemical contamination of the both surface and groundwater bodies of the area. It has resulted in local people being deprived of safe drinking water, plant and aquatic life has severely affected, and situation is deteriorating over the years in the area in spite of some preventive and remedial measures being initiated. The focus of the present study is to understand the chemical characteristics of groundwater and geochemical processes the contaminant water is undergoing which are normally imprinted in its ionic assemblages. The water samples collected in pre- and post-monsoon seasons from forty two groundwater and four surface water sources were analyzed for major constituents such as Ca(2+), Mg(2+), Na(+), K(+), CO (3) (-) , HCO (3) (-) , Cl(-), SO (4) (2-) , NO (3) (-) , and F(-), and selected samples were tested for ten important trace metals like Fe, Pb, Bi, Mn, Cr, Co, Ni, Cu, Zn, and Cd. Na(+) among cations and Cl(-) among anions dominate the water in both the seasons where as Ca(2+), HCO (3) (-) , and Cl(-) show significant reduction in their ionic strength in post-monsoon. The groundwater in general is of mixed type, but most of it belong to Na(+)-Cl(-), Na(+)-HCO (3) (-) , Ca(2+)-Mg(2+)-HCO (3) (-) , and Ca(2+)-Mg(2+)-Cl(-) facies. The Na(+) and Ca(2+) are in the transitional state with Na(+) replacing Ca(2+) and HCO (3) (-) -Cl(-) due to physiochemical changes in the aquifer system. The evaluation of hydrochemistry through various ionic indices, ratios, and plots suggest that silicate-carbonate weathering, ion exchange, dissolution, and evaporation processes are responsible for origin of the present chemical status of the groundwater which is also controlled by the contamination from extraneous sources that could have accelerated the dissolution processes. Gibbs plots authenticate that the evolution of water chemistry is influenced by interaction of percolating water with aquifer matrix apart from anthropogenic enrichment of elements which get over concentrated due to evaporation.

Hydrogeochemical characterization of small coastal wetlands and forests in the Southern Po plain (Northern Italy)

AbstractThis study is aimed to characterize the shallow groundwater system in the coastal area between the Uniti and Bevano rivers (southern part of the Po plain), where salinization is threatening the coastal ecosystems and posing a major environmental issue for the phreatic water management in the coast. A thin rainwater lens is present at the top of the aquifer in the backshore area and its extent has a seasonal variability. These few centimetres of freshwater represent a thin interface between sea water and the delicate coastal ecosystems, such as those of dunes and wetlands. To have a better understanding of the changes in groundwater chemistry, we performed a seasonal monitoring of the water quality at the top of the aquifer. Effective concentrations of chemicals and actual values of physical‐chemical parameters in the rainwater lens could be measured by means of auger holes. The analysis of the cation‐exchange process in the aquifer was made through the application of the Base Exchange index (BEX index) of Stuyfzand (2008), an indicator of salinization or freshening of waters. The results pointed out that a salinization process is taking place in the largest part of the aquifer. Extension and chemical composition of the rainwater lens are strongly influenced by anthropogenic factors such as drainage and land use. The surface water bodies are all brackish to salty and characterized by anoxic and reducing conditions. At present, only halophytes are present around the dune slacks, which have turned into brackish to hypersaline lakes. Copyright © 2011 John Wiley & Sons, Ltd.

Hydrogeochemical characterization of the coastal Paleocene aquifer of Togo (West Africa)

This paper presents a hydrogeochemical characterization of the Paleocene aquifer in the coastal basin of Togo. During the dry season (March, 2005), piezometric measurements were made on inventoried water wells. Fifty nine (59) water samples were taken for chemical analysis and the results subjected to statistical study. The quantitative variables considered for this purpose were temperature, pH, electrical conductivity, the major and some minor elements. The results showed that the water samples were weakly mineralized. The electrical conductivity did not exceed 1000 µS/cm, but it increased considerably in the sulphate rich samples. Hydrochemistry was dominated by calcium and bicarbonate except where important values of sulphate (967 mg/L) were obtained. The results of chemical analysis allowed the definition of four different hydrochemical facies. The calcic and magnesian bicarbonated facies was the most important. A sodic and potassic bicarbonated facies identified was mainly due to the residence time of water in the reservoir. Principal component analysis showed one pole of mineralization with strong correlations between sulphate, carbonate, magnesium and calcium. Key words: Hydrochemistry, aquifer, chemical facies, residence time, Paleocene, Togo.

Hydrogeochemical characterization and isotope investigations of a carbonate aquifer of the northern part of the United Arab Emirates

This paper assesses a carbonate aquifer of the Wadi Al Bih area in the northeastern part of UAE using hydrogeochemical and isotope approaches. Analyses of groundwater samples showed that the TDS and high concentrations of major cations and anions were encountered in the lower segment of the Wadi Al Bih area. Most of the groundwater salinity was noticed downstream of the wadi and this may be attributed to the brines that underlie the groundwater and also to the over-pumping of groundwater with mostly very low recharge. Nitrate concentrations observed in the groundwater of the study area may be ascribed to the nature of the karastic aquifer, which could lead to the dominance of dissolved oxygen that makes NO 3 - the dominant form of nitrogen. The presence of sulfate in collected groundwater samples is due to the gypsum-bearing mudstone in the lower segment of the Wadi Al Bih carbonate aquifer. Majority of the groundwater samples showed the presence of NaCl, which indicates the possible influence of the underlying brine. The mixing process of brine water and freshwater was noted in the shift from CaHCO 3 facies to Ca–Cl facies. The Piper plot showed a Ca-rich to Na-rich water type shift, which could be explained by a cation exchange process. The oxygen and hydrogen isotope compositions in the groundwater samples suggest that the main source of precipitation is the Mediterranean Sea with some possible effects of the Arabian Sea. A trend of increasing chloride concentration with enrichment of hydrogen isotope compositions suggests that groundwater originated from evaporated raindrops or evaporated surface water. The similarity of oxygen and hydrogen isotope compositions between the Eastern Gravel Plain, Ophiolite, and the northern carbonate aquifers indicates the presence of a common source of recharge.

Hydrogeochemical characterization of fluoride rich groundwater of Wailpalli watershed, Nalgonda District, Andhra Pradesh, India

The groundwater of Nalgonda district is well known for its very high fluoride content for the past five decades. Many researchers have contributed their scientific knowledge to unravel causes for fluoride enrichment of groundwater. In the present paper, an attempt has been made to relate the high fluoride content in the groundwater to hydrogeochemical characterization of the water in a fracture hard rock terrain--the Wailpally watershed. Groundwater samples collected from all the major geomorphic units in pre- and post-monsoon seasons were analyzed for its major ion constituents such as Ca(2+), Mg(2+), Na(+), K(+), CO3-, HCO3-, Cl(-), SO4(-2), NO3-, and F(-). The groundwaters in the watershed have the average fluoride content of 2.79 mg/l in pre-monsoon and 2.83 mg/l in post-monsoon. Fluoride concentration in groundwater does not show perceptible change neither with time nor in space. The ionic dominance pattern is in the order of Na(+) > Ca(2+) > Mg(2+) > K(-) among cations and HCO3- Cl(-) > SO4(-2) NO3- F(-) among anions in pre-monsoon. In post-monsoon, Mg replaces Ca(2+) and NO3- takes the place of SO4(-2). The Modified Piper diagram reflect that the water belong to Ca(+2)-Mg(+2)-HCO3- to Na(+)-HCO3- facies. Negative chloralkali indices in both the seasons prove that ion exchange between Na(+) and K(+) in aquatic solution took place with Ca(+2) and Mg(+2) of host rock. The interpretation of plots for different major ions and molar ratios suggest that weathering of silicate rocks and water-rock interaction is responsible for major ion chemistry of groundwater in Wailpally watershed. Chemical characteristics and evolution of this fluoride-contaminated groundwater is akin to normal waters of other hard rock terrain; hence, it can be concluded that aquifer material play an important role in the contribution of fluoride in to the accompanying water. High fluoride content in groundwater can be attributed to the continuous water-rock interaction during the process of percolation with fluoride-bearing country rocks under arid, low precipitation, and high evapotranspiration conditions.

The hydrogeochemical characterization of Morsott-El Aouinet aquifer, Northeastern Algeria

A study of the hydrogeochemical processes in the Morsott-El Aouinet aquifer was carried out with the objective of identifying the geochemical processes and their relation with groundwater quality as well as to get an insight into the hydrochemical evaluation of groundwater. The high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation. A combined hydrogeologic and isotopic investigation have been carried out using chemical and isotopic data to deduce a hydrochemical evaluation of the aquifer system based on the ionic constituents, water types, hydrochemical facies and factors controlling groundwater quality. The ionic speciation and mineral dissolution/precipitation was calculated by WATEQF package software. The increase in salinity is related to the dissolution and/or precipitation processes during the water–rock interaction and to the cationic exchange reactions between groundwater and clay minerals. The isotopic analysis of some groundwater samples shows a similarity with the meteoric waters reflect their short residence time and a lowest evaporation phenomenon of infiltrated groundwater.

Statistical approaches for hydrogeochemical characterization of groundwater in West Delhi, India

Parametric statistical approaches, correlations and multiple linear regressions were used to develop models for the interpretation of hydrogeochemical parameters in the Western part of Delhi state, India. The hydrogeochemical parameters indicated that the groundwater quality is not safe for consumption. The water is moderately saline and the salinity level is increasing over time. There is also the problem of nitrate pollution. The correlation between electrical conductivity (EC) and other water quality parameters except potassium (K(+)), nitrate (NO(3)(-)) and bicarbonate (HCO(3)(-)) is significantly positive and Ca(++)+ Mg(++)/Na(+)+ K(+) is significantly negative. In predicting EC, the multiple R(2) values of 0.996 and 0.985 indicate that 99.6% and 98.5% variability in the observed EC could be ascribed to the combined effect of Na(+), HCO(3)(-), Cl(-), SO(4)(--), NO(3)(-) and Ca(++)+ Mg(++) for the year of 2005 and 2006 respectively. Out of 99.6% of the variability in EC in 2005, 51.2% was due to Cl(-) alone, and 8.5%, 12.5%, 6.1%, 14.7% and 6.7% were due to Na(+), HCO(3)(-), SO(4)(--), NO(3)(-) and Ca(++) + Mg(++). Similarly in 2006, out of 98.5% of the variability in EC, 48.5% was due to Cl(-) alone, and 10.4%, 12.7%, 5.3%, 17.2% and 4.4% were due to Na(+), HCO(3)(-), SO(4)(--), NO(3)(-) and Ca(++)+ Mg(++). The analysis shows that a good correlation exists between EC, Cl(-) and SO(4)(--) either individually or in combination with other ions and the multiple regression models can predict EC at 5% level of significance.

High-level radioactive waste disposal in Sweden: Hydrogeochemical characterisation and modelling of two potential sites

High-level radioactive waste disposal in Sweden: Hydrogeochemical characterisation and modelling of two potential sites

Potentiometrically measured Eh in groundwaters from the Scandinavian Shield

Measurement and interpretation of electrochemical Eh values in natural reducing groundwaters is a complex task. SKB, the company in charge of disposal of nuclear fuel wastes in Sweden, has developed a refined methodology for the determination of this parameter in packered sections in boreholes. The methodology consists of the simultaneous use of three different electrodes (Pt, Au and C) both at depth and at the surface, and maintaining continuous logging over a long period of time. Apart from Eh, the logging also includes other parameters such as pH, dissolved O2, conductivity and temperature. This methodology has been used since the 80s in the framework of the hydrogeochemical characterisation programs supported by SKB at different sites in the Scandinavian Shield. All the existing databases have been revisited in this work using a uniform set of criteria to select Eh values of the Swedish groundwaters as a function of depth. The selected Eh dataset ranges from −140 to −400 mV and corresponds to waters with pH values between 7 and 8.6 at depths between 110 and 1000 m. Eh shows no correlation with depth in any of the fractured aquifers of the studied sites. The Eh values, together with the results obtained from the geochemical modelling and the microbiological studies in the ongoing work at Laxemar and Forsmark have allowed the study of the relationship between the potentiometrically measured Eh and the redox pairs controlling it. The possible control of the redox conditions by the electroactive pair Fe2+/Fe(OH)3(s) in waters with a wide range of measured Eh values suggests either the involvement of different kinds of Fe oxyhydroxides or variations of crystallinity and/or particle size in them. The good fit found between the measured Eh and the results obtained with different S redox pairs, together with the occurrence of SRB and the equilibrium situations with respect to the amorphous Fe(II) monosulphides, suggest the participation of the S system in the measured Eh control.

Hydrogeological and hydrogeochemical characterization of a karstic mountain region

Hydrogeological and hydrogeochemical characterization of a karstic mountain region

The hydro geochemical characterization of ground waters in Tunisian Chott’s region.

Tunisian Chott’s region is one of the most productive artesian basins in Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. The chemical composition of the water is strongly influenced by the interaction with the basinal sediments and by hydrologic characteristics such as the flow pattern and time of residence. The system is composed of an upper unconfined “Plio-Quaternary” aquifer with a varying thickness of 20–200 m, an intermediate confined/unconfined “Complex Terminal” aquifer about 100 m in thickness and a deeper “Continental Intercalaire” aquifer about 150 m in thickness separated by thick clay and marl layers. The dissolution of evaporites and carbonates explains part of the contained Na+, Ca2+, Mg2+, K+, SO42− and Cl-, but other processes, such carbonate precipitation, also contributes to the water composition. The stable isotope composition of waters establishes that the deep groundwater (depleted as compared to present corresponding local rainfall) is ancient water recharged probably during the late Pleistocene and the early Holocene periods. The relatively recent water in the Plio-Quaternary aquifer is composed of mixed waters resulting presumably from upward leakage from the deeper groundwater.

Hydrogeological and hydrogeochemical characterization of a karstic mountain region

Karstic limestone formations in the Mediterranean basin are potential water resources that can meet a significant portion of groundwater demand. Therefore, it is necessary to thoroughly study the hydrogeology and hydrogeochemistry of karstic mountain regions. This paper presents a detailed hydrogeological and hydrogeochemical characterization of the Nif Mountain karstic aquifer system in western Turkey, an important recharge source for the densely populated surrounding area. Based on the geological and hydrogeological studies, four major aquifers were identified in the study area including the allochthonous limestone in Bornova flysch, conglomerate-sandstone and clayey-limestone in Neogene series, and the Quaternary alluvium. Physicochemical characteristics of groundwater were measured in situ, and samples were collected at 59 locations comprised of springs and wells. Samples were analyzed for major ions, isotopic composition, arsenic, boron and heavy metals among other trace elements. It was found that the hydrogeological structure is complex with many springs having a wide range of discharge rates. High-discharge springs originate from allochthonous limestone units, whereas low-discharge springs are formed at the contacts with claystone and limestone units. Using stable isotope analysis data, a δ18O-deuterium relationship was obtained that lies between the Mediterranean meteoric and mean global lines. Tritium analyses showed that low-discharge springs originating from contact zones had longer circulation times compared to the high-discharge karstic springs. Furthermore, hydrogeochemical data revealed that groundwater quality significantly deteriorated as water moved from the mountain to the plains. Heavy metal, arsenic and boron concentrations were generally within drinking-water quality standards with a few exceptions occurring in residential and industrial areas located at the foothills of the mountain. Elevated arsenic concentrations were related to local geologic formations, which are likely to contain oxidized sulfite minerals in claystones. It is concluded that Nif Mountain overall has a significant potential to provide high-quality water with a safe yield of at least 50 million m3/year, which corresponds to about 28% of the mean annual inflow to the Tahtali reservoir, a major water resource for the city of Izmir.

Hydrogeochemistry of the Coxilha das Lombas Aquifer, Brazil

The hydrogeochemical characterization of Coxilha das Lombas Aquifer, Brazil, was studied. Chemical characteristics from 23 groundwater samples and meteoric waters data from public registers were used. The ionic speciation and mineral dissolution/precipitation was calculated by EQ3/6 package software. The results showed low total dissolved solids (TDS) values and slightly acidic pH. The concentration of most abundant ions usually followed this trend Cl−>HCO3 +>SO4 2−>Na+. The characteristics of groundwaters and the chemistry similarity with the meteoric waters reflect their short residence time, due to high hydraulic conductivity, and low degree of water/rock interactions, due to sands composed mainly of quartz.

Redox pathways in a petroleum contaminated shallow sandy aquifer: Iron and sulfate reductions

A comprehensive hydro-geochemical characterization was carried out in a petroleum-contaminated shallow sandy aquifer in South Africa. The results indicate the presence of a BTEX (benzene, toluene, ethylbenzene, and xylene) plume that has moved, although only slightly, along the regional hydraulic gradient from the spill site. Associated with the contaminant plume, spatial distribution pattern of terminal electron acceptors and metabolites indicates simultaneous occurrence of nitrate, manganese, iron and sulfate reductions resulting in overlapping redox zones within the aquifer. From the measured concentration of metabolic by-products, sulfate and iron reductions seem to be the dominant metabolic pathways, though. Incubation experiments conducted with hydrocarbon contaminated aquifer sediments and inherent microbial assemblages provide a sulfate reduction rate of 4272 nmol cm − 3 day − 1 and 96 nmol cm − 3 day − 1 for winter and summer, respectively. As oppose to this, iron reduction dominates in summer with measured respiration rate of 1414 nmol cm − 3 day − 1 . In winter iron reduction was measured to be only 24 nmol cm −3 day − 1 . Based on the dissimilatory iron and sulfate reduction rate measurements, we predict that at the aquifer site, intrinsic BTEX oxidation is primarily occurring in winter and is coupled to sulfate reduction. Although widespread in the aquifer, the contribution of iron reduction for the removal of aromatic monocyclic hydrocarbons is relatively minor.

Geostatistical Analysis for Hydrogeochemical Characterization of the Han River, Korea: Identification of Major Factors Governing Water Chemistry

Geostatistical Analysis for Hydrogeochemical Characterization of the Han River, Korea: Identification of Major Factors Governing Water Chemistry

Use of non-parametric statistics as a tool for the hydraulic and hydrogeochemical characterization of hard rock aquifers

Synopsis The new EU Water Framework Directive (Directive 2000/60/EC) implies that hard rock units will need to be considered as aquifers, and to be hydrogeologically and hydrogeochemically characterized. This is not a straightforward task, given that such aquifers are heterogeneous, discontinuous and strongly three-dimensional in the distributions of both hydraulic and hydrochemical properties. The Geological Survey of Norway has recently carried out characterizations of Norway’s hard rock aquifers using simple non-parametric statistical techniques, focusing on median and percentile values for aquifer properties and concentrations of chemical parameters. Such characterizations reveal far larger parameter ranges within given aquifer lithological units than between different units. Indeed, for most lithologies, median well yields and concentrations of major chemical parameters (e.g. pH, major ions) are remarkably similar. For certain elements, however, systematic differences can be detected. For example, elements such as uranium, radon and fluoride are significantly enriched in Precambrian granites and gneisses, and depleted in anorthosites.

Hydrogeochemical characterization of major factors affecting the quality of shallow groundwater in the coastal area at Kimje in South Korea

This study has evaluated the main hydrogeochemical characteristics that affect the quality of shallow groundwater in the coastal area at Kimje in South Korea. In this area, the chemical composition of groundwater is mostly classified into Na+−Cl− and Ca2++Mg2+−NO3-+Cl− types. These types are affected by three major factors: seawater intrusion, fertilizers and redox processes. The Na+−Cl− type, which is generally localized in the coastal area, shows typical characteristics of groundwater affected not only by modern seawater but also by old seawater residing in the reclaimed land. In contrast, the Ca2++Mg2+−NO3-+Cl− type, which is usually found inland, is very contaminated by fertilizers. As groundwater flows from the inland area to the coast, the redox condition changes from an oxic condition to a suboxic/anoxic condition. In addition, the reclamation has caused a large amount of underlying organic matter. These effects provide optimum conditions for the occurrence of redox processes in the coastal area.

Factors which determine the hydrogeochemical behaviour of karstic springs. A case study from the Betic Cordilleras, Spain

The Cabra-Alcaide karstic massif situated in the south of Spain constitutes an important part of the so-called Natural Park of the Subbetic Sierras. This aquifer system is drained by various springs which supply a population of some 100,000 inhabitants. The feed areas of these springs show very different characteristics with respect to their geological structure, size of the drainage area, thickness of the vadose zone, elevation and degree of karstification. In addition, the carbonate rocks lie over a clayey substratum which contains large masses of intercalated evaporites. Due to these conditions, the hydrochemical composition of the springs is relatively variable. In this study a hydrogeochemical characterization of the aquifer in both space and time is undertaken and the factors that determine it are discussed. To achieve this, 19 monthly samples were taken from the 6 most significant springs of the hydrogeological system. The commencement of sampling coincided with the transition from a period of several years of severe drought and a very wet two-year period, which amplified considerably the hydrochemical and hydrodynamic response of the springs to the recharge. Identification of hydrogeochemical processes was performed by studying hydrographs, the temporal evolution of physico-chemical parameters, ionic ratios (mainly Mg/Ca) and by means of simple and multivariate statistical analyses. The saturation status was established using the WATEQF program and the mass transfer was quantified using PHREEQC. With the exception of the epikarstic subsystem (i.e. the Zarza spring), the majority of the results indicate that the aquifer exhibits a diffuse flow model, in which piston flow phenomena are seen, closely linked to the most intense precipitation. Along the direction of flow hydrochemical trends are seen as the water type changes from Ca–HCO 3 to Ca–Mg–HCO 3; at the same time enrichment in some ions, derived from the dissolution of evaporitic minerals of the impermeable substratum, and dedolomitization processes occur. In this way, almost 90% of the water samples were oversaturated in calcite, the majority of cases being a consequence of the dissolution of the gypsum of the substratum. Only in the epikarstic springs can it be considered that the oversaturation in calcite is due to loss of CO 2 from the emerging groundwater. It is concluded that hydrodynamic aspects together with hydrogeochemical characteristics need to be taken into account to correctly explain the hydrochemical evolution of the karstic springs. Moreover, the use of both approaches permits a more accurate establishment of the degree of aquifer karstification, which in turn needs to be known in order to assess its vulnerability to contamination and to protect recharge zones.