Calcium Magnesium Bicarbonate Research Articles

Hydrogeochemical assessment and spatial analysis of groundwater quality parameters in North West of Morocco

Global warming, population growth, agricultural intensification, and rising industrial productivity have affected groundwater quality. However, assessing groundwater quality enables us to understand the risk of contamination better and protect these natural resources in the long term. The objectives of this study are to evaluate the physicochemical parameters of groundwater for human drinking purposes in North West of Morocco and to identify their geogenic and/or non-geogenic origins through the use of graphical diagrams (Piper and Schoeller Berkaloff) and by GIS interpolation tools to recognize the main geochemical processes governing groundwater quality.For this purpose, the physico-chemical parametrs analyzed of groundwater in the Bouregreg basin and the southern part of the Sebou basin, using 51 water points in the study region’s rural area. Specific physicochemical water parameters (pH, TH, TAC, and electrical conductivity), cations (K+, Na+, Ca2+, and Mg2+), and anions (Cl-, NO3–, HCO3– and SO42-) were measured and analyzed for human consumption. Piper diagrams and ArcGIS geoprocessing were used to identify groundwater hydrochemical facies and study the spatial distribution of estimated parameters concerning geology and anthropogenic factors.All the parameters measured were below the threshold values required by the WHO for human drinking water, except nitrates, recorded in one sample at a concentration of 88.75 mg/L. Piper and Schoeller Berkaloff diagrams show that strong acid (Cl-) and weak acid (HCO3–) appear considerably over the other acids (NO3– and SO42-). In contrast, most sources show no cation dominance. The Calcium and magnesium chloride facies (43 %) and Calcium-magnesium bicarbonate facies (35 %) are the most facies presnent in this stydy. Geoprocessing showed that the chemical composition of the various sampling points is governed mainly by lithological diversity, except for S35, which showed an anthropogenic origin.

Thermal stratification and meromixis in four dilute temperate zone lakes

Abstract. Four adjacent lakes (Arco, Budd, Deming, and Josephine) within Itasca State Park in Minnesota, USA, are reported to be meromictic in the scientific literature. However, seasonally persistent chemoclines have never been documented. We collected seasonal profiles of temperature and specific conductance and placed temperature sensor chains in two lakes for ∼1 year to explore whether these lakes remain stratified through seasonal mixing events and what factors contribute to their stability. The results indicate that all lakes are predominantly thermally stratified and are prone to mixing in isothermal periods during spring and fall. Despite brief, semi-annual erosion of thermal stratification, Deming Lake showed no signs of complete mixing from 2006–2009 and 2019–2022 and is likely meromictic. However, the other lakes are not convincingly meromictic. Geochemical data indicate that water in Budd Lake, which contains the most water, is predominantly sourced from precipitation. The water in the other three lakes is of the calcium–magnesium–bicarbonate type, reflecting a source of water that has interacted with the deglaciated landscape. δ18OH2O and δ2HH2O measurements indicate the lakes are supplied by precipitation modified by evaporation. Josephine, Arco, and Deming lakes sit in a valley with likely permeable sediments and may be hydrologically connected through wetlands and recharged with shallow groundwater, as no streams are present. The water residence time in meromictic Deming Lake is short (100 d), yet it maintains a large reservoir of dissolved iron, indicating that shallow groundwater may be an additional source of water and dissolved ions. All four lakes develop subsurface chlorophyll maxima layers during the summer. All lakes also develop subsurface oxygen maxima that may result from oxygen trapping in the spring by rapidly developed summer thermoclines. Documenting the mixing status and general chemistry of these lakes enhances their utility and accessibility for future biogeochemical studies, which is important as lake stratification and anoxia are becoming more prevalent due to changes in climate and land use.

Analysis of the Recharge Area of the Perrot Spring (Aosta Valley) Using a Hydrochemical and Isotopic Approach

The Perrot Spring (1300 m a.s.l.), located to the right of the Chalamy valley in the Monte Avic Natural Park (Valle d’Aosta, Italy), is an important source of drinking water for the municipality of Champdepraz. This spring is located on a large slope characterised by the presence of a Quaternary cover of various origins (glacial, glaciolacustrine, and landslide) above the bedrock (essentially serpentinite referred to the Zermatt–Saas Zone, Penninic Domain). Water emerges at the contact between the landslide bodies and impermeable or semi-permeable glaciolacustrine deposits. The aim of this study is to define the processes and recharge zones of this spring. The analysis of the data revealed the presence of two contributions to the Perrot Spring input: a spring thaw contribution defined by a small increase in flow and an autumn contribution from rainwater infiltration. The low average temperature and low variation of the annual temperature (4.8–6.5 °C) suggest a sufficiently deep flow circuit. Chemical analyses showed a groundwater chemistry consistent with the regional geology: the hydrochemical facies is calcium–magnesium bicarbonate and isotopic analyses (δ2H and δ18O) of rainfall and spring water suggested a recharge altitude of about 2100 m a.s.l. In conclusion, this study makes it possible to recognize the water inputs to the spring discharge and to delineate its recharge area, which can be proposed to implement strategies to protect the resource.

Comprehensive Evaluation of Water Resource Characteristics in the Northern Yangtze River Delta, China

The Yangtze River Delta is one of the most economically developed regions on the eastern coast of China. However, a local imbalance currently exists between its water resource environment and economic and social development due to its rapid urbanization. Thus, the reasonable evaluation and protection of local water resources are necessary. This study explores the northern Yangtze Delta, which is a more developed water system, as a pilot area. The temporal and spatial variation characteristics of rainfall and evaporation and their influencing factors were analyzed on the basis of 29 surface water sampling points, 16 rainfall stations, and three evaporation stations in the field from 1956 to 2019. Accordingly, the overall water supply quality of the river basin, the availability of different water resources, and the application of evaluation methods were assessed. Results show that local precipitation and evaporation are characterized by uneven spatial and temporal distributions in local areas, which, in turn, leads to the uneven temporal distribution of runoff, increasing the imbalance between the availability and demand of the limited local water resources. Nevertheless, the overall performance of local water quality is good. Surface water quality is mostly Ⅱ to Ⅲ, and locally Ⅳ. Most noncompliant months are during the non-flood season, and all values exceed the standard permanganate index. Groundwater is Class III or better, and the hydrochemistry type is predominantly calcium bicarbonate, sodium bicarbonate, and magnesium bicarbonate. By exploring the evaluation model of the Yangtze River Delta watershed characteristics, this study aims to provide a helpful reference for extending water resource evaluation in the Yangtze River Delta. Accordingly, this study can promote the sustainable development of the economic and social sectors of the Yangtze River Delta and the construction of its ecological environment.

HYDROGEOCHEMICAL CHARACTER AND GROUNDWATER POTENTIAL IN TERNATE BASIN, NORTH MALUKU, INDONESIA

Ternate Basin is located a small volcanic island in the archipelago of North Maluku, Indonesia. This island has very limited water resources and prone to seawater intrusion. This study aims to determine and analyze the distribution of hydrogeological interest points, determine patterns and directions of groundwater flow, and analyze hydrogeochemical quality and groundwater facies. Determination of the free aquifer zone was carried out by geoelectric measurements in 37 points, while the interpretation of confined aquifers was carried out in 17 drill log points. The quality of groundwater was analyzed in the study area, 126 samples were collected and analyzed. The piper diagram was adopted to identify groundwater facies. The determination of groundwater basin with a total recharge of 54,155 million m3/year. The saturated zone of groundwater flow reaches 1.237 million m3/day or 451.712 million m3/year. The quality of groundwater laboratory results indicates that the water from the two aquifer sources is suitable as a source of drinking water with moderate permeability and has met the quality standards. There were three groundwater facies in the study sites consisting of calcium magnesium bicarbonate (C4H4-Ca-MgO12), calcium magnesium chloride (CaCl2-MgCl2) and sodium potassium chloride (NaCL-KCL). Bicarbonate facies type in the groundwater basin indicated localized flow systems. This means the groundwater in the study site has a recharge area close to its groundwater source. Meanwhile, chloride facies type in the groundwater basin indicates a long process of flow pattern and allows the groundwater to interact with seawater or magmatic matters. These results can be used for policymakers to determine the appropriate and accurate location for groundwater exploitation for the public purposes. Determination of the location must be carried out by considering the flow, quantity, and quality of groundwater.

ANALYSIS OF GROUNDWATER FACIES IN PARAKAN OMAS AND SURROUNDING REGIONS, RUMPIN DISTRICT, BOGOR REGENCY, WEST JAVA, TO DETERMINE GROUNDWATER FACIES.

The research area is located in Parakan Omas Village, Rumpin District, Bogor Regency, West Java Province. The background of this research was to determine the chemical properties of groundwater in the springs in the Parakan Omas area. The method used is taking samples of springs from springs and chemical analysis of the main ions (Mg⁺, Ca²⁺, Na⁺, K⁺, Cl⁻, SO₄²⁻, HCO₃⁻, CO₃⁻) and getting 5 samples of springs entered into the laboratory. The purpose of this study was to determine the chemical characteristics of groundwater in Rumpin sub-district. Lithological conditions affect groundwater facies, volcanic rocks cause groundwater to contain mineral cations Mg⁺ and Ca²⁺ with varying anions while alluvium layers in land areas will cause groundwater to be rich in sodium (Na⁺) minerals with anions in the form of chloride (Cl⁻) or sulfate ( SO₄²⁻). Data analysis using piper trilinear diagram. The diagram shows that there are 2 types of facies in the dominant research area, namely Sodium Potassium Bicarbonate (Na+ + K+ HCO3- ) and Calcium Magnesium Bicarbonate (Ca2+ + Mg2+HCO3⁻).

Geochemical evaluation of groundwater quality of Peshawar Basin, Pakistan

Evaluation of groundwater quality is vital due to its diverse use for several purposes. In the present study, groundwater quality and suitability from the Peshawar basin, Pakistan, were evaluated for drinking and irrigation purposes. The water samples were analysed for major cations (Ca, Mg, Na and K) and anions (chloride, bicarbonate and sulphate) along with other physicochemical parameters (pH, electrical conductivity, total dissolved solids, and total hardness). About 95% of the water samples were found to be within the WHO, US-EPA and Pak-EPA permissible levels for drinking purposes. Seventy percent (70$) of the water samples belonged to the hard water category. Irrigation water quality parameters, such as, chloride, residual sodium bicarbonate, sodium adsorption ratio, percent sodium, magnesium adsorption ratio, Kelly' s ration and permeability index were evaluated which demonstrated that the groundwater was highly to moderately suitable for irrigation. A correlation study was conducted to find out the mutual associations among the variables. Piper diagram indicated the overall chemical nature of the study area was calciummagnesium bicarbonate type. Cluster analysis revealed mutual apportionment of various parameters in the groundwater of the Peshawar basin, Pakistan.

Contamination, sources and environmental risk assessment of heavy metals in water, sediment and soil around an abandoned Pb mine site in North East Morocco

Metal Mining Contamination is a widespread problem in the world. However, the assessment of abandoned mine metal contamination, especially in Morocco, has not been studied sufficiently. In this study, a total of 83 samples of water, sediments, and soils were collected to investigate the concentrations of heavy metals (HMs) around an abandoned mining area, named: Zeida in North East Morocco. Furthermore, geochemical mapping of these elements has been also conducted. The contamination and environmental risk introduced by the accumulation of HMs has been assessed using numerous ecological indexes, such as: geo-accumulation (Igeo), Potential Ecological Risk Index and Modified Contamination Degree (MCd) to name just a few. Add to that the assessment of water quality using water quality assessment indexes. The results showed that all major elements and HMs of the river and its tributaries were within the Guidelines for Drinking-Water Quality (GDWQ), except for levels of HCO3−, and K+. The hydrochemical facies was dominated by calcium magnesium bicarbonate (CaMg–HCO3), and the concentrations changed in the range (µg/l): Zn: 14.78–152.00, Cr: 2.56–13.23, Cu: 0.96–12.35, Pb: 0.03–11.26, As: 0.98–3.24, Ni: 0.11–1.34 and Cd: 0.01–0.31, respectively. The spatial distribution of HM concentration and numerous ecological indexes in soil and sediment samples revealed that the highest values were located in and near the tailings, and declined downstream, which classified these sites as very highly contaminated and severely hazardous. Vertically, the soil concentration of HMs accumulated increasingly in relation to depth, and that in fact highlighted their potential mobility. HM concentrations (mg/kg) in sediments were in the range of: Pb: 43.79–9889.30, As: 104.57–289.00, Cr: 25.84–125.00, Zn: 40.78–121.75, Cu: 8.85–36.11, Ni: 1.99–21.00 and Cd: 0.10–0.46, respectively. While the average concentration in the three depths of soil (mg/kg) were in the range of: Pb: 27.00–11,400.00, Zn: 36.00–231.33, As: 42.33–172.00, Cr: 21.67–105.33, Cu: 18.33–143.33, Ni: 13.67–40.33 and Cd: 0.04–1.33, respectively. Multivariate statistical analysis indicated that HMs were related to the dispersion of tailings materials, with the exception of Ni and Cr which were related to lithological source.

Aquifer distribution and groundwater geochemistry in Bojonegoro Sub-district, Bojonegoro District, East Java Province, Indonesia

Bojonegoro Sub-district is the capital of Bojonegoro District, East Java Province, Indonesia. This area has quite high economic growth supported by large oil and gas reserves in the district. An increasing number of population and improving economy will cause more water needs. People in this area use groundwater as their main source for daily purposes. However, information on the potential of groundwater resources is not yet well available. Therefore, the study aims to determine groundwater flow patterns, the distribution of aquifers, and groundwater geochemistry. The study was conducted by measuring groundwater level as many as 42 points; both dug wells and deep wells, 18 points geo-electrical surveys, and chemical analysis of eight groundwater samples. The results showed groundwater flow direction into the Bengawan Solo River with the primary aquifer of the sandstone lens. All groundwater samples indicate that the type of groundwater is calcium magnesium bicarbonate (Ca 2+ - Mg 2+ - HCO 3 - ) and come from one system. High nitrate content was found in some areas, probably due to contamination from agricultural or urban wastewater. Therefore, it needs some actions for groundwater protection and conservation in this area to support the sustainable use of groundwater.

Investigation of Groundwater Quality from Selected Wells in Paiko, Northcentral Nigeria

Groundwater from hand dug wells and boreholes in Paiko, northcentral Nigeria were subjected to physico-chemical as well as microbiological analysis to determine their suitability for drinking purpose. The water from the hand dug wells are predominantly calcium magnesium chloride (Ca-Mg-Cl) water while those from boreholes are calcium magnesium bicarbonate water (Ca-Mg-HCO3) facies. The results showed elevated cations and anions concentration in the hand dug wells in addition to the water being slightly acidic. Also, the nitrate concentration in the hand dug wells is above the maximum permissible limit of 50mg/l postulated by World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDQ). Microbiological analysis revealed Total Coliform Count of 100cfu and 360cfu in the hand dug wells and borehole respectively signifying faecal contamination. The study revealed that improper sewage systems as well as poor waste disposal is responsible for the poor water quality as well as elevated concentration of nitrate in hand dug wells, and as such the shallow aquifer groundwater in the area are not safe for drinking purpose with respect to all the parameters taken together.

Determining groundwater facies and water quality index in Tanah Bumbu Regency/South Borneo Indonesia

Most people in Tanah Bumbu Regency use water from dug wells for their daily activities. Kotabaru Regency is located in Pagatan Groundwater Basin, which is located in three administrative boundaries, namely Tanah Laut Regency, Tanah Bumbu Regency, The purposes of this study are to determine the type of groundwater facies and Water Quality Index (WQI). The methods were hydrogeological mapping and hydrogeochemical analysis of groundwater samples to evaluate groundwater quality. There were 170 groundwater samples mapped in the study area. The study area has differences in groundwater quality in both confined aquifer and unconfined aquifer. The unconfined aquifer has two types of groundwater facies, namely Ca-Mg-HCO3 (Calcium Magnesium Bicarbonate) and Ca-Cl (Calcium Chloride). In comparison, the confined aquifer has two types, which are Ca-Mg-HCO3- (Calcium Magnesium Bicarbonate) and Na-HCO3- (Sodium Bicarbonate). Based on the calculation of the Water Quality Index (WQI) of unconfined aquifer samples show that 70% of groundwater samples have poor quality. Meanwhile, the confined aquifer samples indicate that 85% of groundwater samples have good to excellent, which is suitable for drinking water.

Hydrogeological research in the Ordesa and Monte Perdido National Park (Huesca, Spain)

The National Park of Ordesa and Monte Perdido (PNOMP) is the largest mountainous limestone massif of Western Europe. It has the highest altitude karst of the whole Europe. Groundwater is essential for the genesis, development and evolution of the park. The spatial distribution of recharge infiltration capacity is obtained by using the APLIS method. Additionally, a preliminary estimation of recharge is obtained by using the HBV and Visual Balan codes. The values of average surface runoff, evapotranspiration and recharge for the whole Paleocene-Eocene aquifer in the park are respectively about 160, 360 and 1227 mm/yr, or 10, 20 and 70% of yearly precipitation. Average recharge ranges between 72 and 77% of yearly average precipitation. This highlights the high vulnerability of water resources of PNOMP to possible climate and global change, according to surface and deep karstification and the snow cover during several months a year. Water is mainly of the calcium bicarbonate and calcium-magnesium bicarbonate types. There is a dominant process of calcite dissolution, which is consistent with the carbonate nature of the most abundant materials in the park (Upper Cretaceous and Lower Paleocene Eocene). Other observed hydrogeochemical processes are anhydrite and/or gypsum dissolution, as well as a possible incongruent dissolution of dolomite in the Ordesa Valley. Water stable isotopes show that the fronts that produce the greatest precipitations come from the Atlantic Ocean. In autumn, winter and spring there is a deuterium excess in the recharge water which is assumed to be related with diurnal snow sublimation and night water vapour condensation over the snow pack. The recharge elevation zone is located between 1950 and 2600 m asl, and most of the sampled springs show short transit times, between 1 and 4 years, although one of the springs (Fuen dero Baño) shows the influence of a slowly changing regional groundwater flow system.

Efeito da descontinuidade estrutural na hidrogeoquímica do aquífero Barreiras no nordeste do Brasil

O aquífero Barreiras no campo de poços de Boa Cica, localizado no município de Nísia Floresta/RN, é composto por rochas siliciclásticas com espessura média da ordem de 65 metros. Na área estudada se encontra sobreposto a um aquitardo Mesozóico carbonático. Ambas as unidades, localmente, são interceptadas por um sistema de falhas nas direções NE-SW e NW-SE. O objetivo do presente trabalho é o entendimento da interação entre a estruturação geológica da área e as variáveis hidrogeológicas e hidrogeoquímicas do aquífero Barreiras. As descontinuidades geradas pelas falhas propiciam caminhos de fluxo preferencial através dos quais ocorrem interações das águas subterrâneas do aquitardo e do aquífero, em profundidade por fluxo vertical ascendente. Corroborando, observa-se dois grupos distintos de águas em poços captando o aquífero Barreiras: Grupo 1, com fácies cloretada sódica, típica do aquífero Barreiras; Grupo 2, com fácies bicarbonatada cálcica a magnesiana, com influência do aquitardo carbonático.

Caracterização hidroquímica e isotópica dos aquíferos fissurais da região de Itabuna/BA

Os aquíferos cristalinos representam importantes reservas de águas em termos mundiais e são caracterizados pela complexidade que governam o movimento e o armazenamento da água em suas descontinuidades geológicas. Igualmente complexos são os mecanismos atuantes na interação rocha/água. O entendimento dos processos físicos e geoquímicos atuantes nestes aquíferos é crucial para sua gestão. Este trabalho apresenta uma caracterização hidroquímica preliminar das águas do aquífero fissural na região de Itabuna/BA, a partir da identificação dos tipos hidroquímicos dominantes. As análises químicas indicam elevada variabilidade da composição química da água, que pode estar associado à ocorrência de vários processos distintos, incluindo a interação com a água marinha e diferentes graus de interação com as rochas que hospedam a água em suas descontinuidades geológicas. As amostras de águas subterrâneas foram reunidas em dois grupos distintos: o primeiro grupo é representado por água do tipo cloretado sódico e menores valores de condutividade elétrica, associados às amostras coletadas nas porções mais rasas de sub-superfície; o segundo grupo é representado por tipos hidroquímicos bicarbonato sódico, cálcico ou cálcio-magnesianos, provavelmente associadas às águas com elevado grau de interação com as rochas do aquífero, proveniente de recarga pretérita. Os resultados de análise isotópica da água subterrânea e meteórica sugerem a existência de um leve excesso de deutério, decorrente de condições climatológicas locais.

Hydrochemistry of shallow groundwater and springs used for potable supply in Southern Brazil

Landscape characteristics and access type may exert a strong influence on groundwater quality, thereby adversely affecting human health. The aim of this study was to evaluate groundwater quality in springs and shallow wells of rural areas in terms of hydrochemical properties and different water quality indexes by comparing distinct microregions, groundwater sources (springs and shallow wells), and surrounding properties (e.g., presence of livestock, presence of fences, other protection structures, and restrictions on human access). Physical–chemical, chemical, and microbiological parameters were analyzed over 12 months between 2013 and 2014 in the Marombas River basin located in Santa Catarina State, Southern Brazil. Land use and landforms played an important role in controlling groundwater hydrochemistry in rural areas. The type of groundwater source (springs or shallow wells) did not influence water quality, although springs tended to be more susceptible to bacterial contamination, especially in areas with livestock in the surroundings. Chemical relationships allowed classifying these waters as predominantly calcium–magnesium bicarbonate or calcium–magnesium chloride, the latter being the most common in the study region. Groundwater was acidic, with low dissolved salt content, large range in dissolved oxygen concentrations, low turbidity, and presence of fecal coliforms in most studied months. Results indicate that water might be affected by septic tank leakage associated with wastewater and output from agricultural fields, given precarious installation and conservation conditions of springs and shallow wells in this region. When comparing the results with drinking water standards established by Brazilian Health Ministry, 70% of springs and shallow wells were found not suitable for consumption, especially due to organoleptic properties, high aluminum concentrations, and presence of fecal coliforms. Water quality indexes demonstrated that groundwater is suitable for agricultural uses (irrigation, livestock, and fish farming) and drinking, if treated via disinfection, filtering, or boiling before consumption. Nevertheless, use of this water resource, especially without any treatment—as is currently common among users—raises concerns related to its susceptibility to spread waterborne diseases, and lack of information among water users regarding procedures to improve water quality.

Water quality assessment in the Bétaré-Oya gold mining area (East-Cameroon): Multivariate Statistical Analysis approach

The influence of gold mining activities on the water quality in the Mari catchment in Bétaré-Oya (East Cameroon) was assessed in this study. Sampling was performed within the period of one hydrological year (2015 to 2016), with 22 sampling sites consisting of groundwater (06) and surface water (16). In addition to measuring the physicochemical parameters, such as pH, electrical conductivity, alkalinity, turbidity, suspended solids and CN−, eleven major elements (Na+, K+, Ca2+, Mg2+, NH4+, Cl−, NO3−, HCO3−, SO42−, PO43− and F−) and eight heavy metals (Pb, Zn, Cd, Fe, Cu, As, Mn and Cr) were also analyzed using conventional hydrochemical methods, Multivariate Statistical Analysis and the Heavy metal Pollution Index (HPI). The results showed that the water from Mari catchment and Lom River was acidic to basic (5.40<pH<8.84), weakly mineralized (6.3<EC<160.8μS/cm) and had a high concentration of total suspended solids (TSS) (2<TSS<8996.00mg/L). The major elements were all within the World Health Organization (WHO) guidelines for drinking water quality, except for nitrates in some wells, which was found at a concentration >50mg NO3−/L. This water was found as two main types: calcium magnesium bicarbonate (CaMg-HCO3), which was the most represented, and sodium bicarbonate potassium (NaK-HCO3). As for trace elements in surface water, the contents of Pb, Cd, Mn, Cr and Fe were higher than recommended by the WHO guidelines, and therefore, the surface water was unsuitable for human consumption. Three phenomena were responsible for controlling the quality of the water in the study area: hydrolysis of silicate minerals of plutono-metamorphic rocks, which constitute the geological basement of this area; vegetation and soil leaching; and mining activities. The high concentrations of TSS and trace elements found in this basin were mainly due to gold mining activities (exploration and exploitation) as well as digging of rivers beds, excavation and gold amalgamation.

Hydrochemical characteristics of surface and groundwater and suitability for drinking and agricultural use in the Upper Tigris River Basin, Diyarbakır–Batman, Turkey

Investigations were undertaken into the quality of surface water and groundwater bodies within the Upper Tigris Basin in Turkey to determine their suitability for potable and agricultural use. In the study area, the majority of the groundwater and surface water samples belong to the calcium–magnesium–bicarbonate type (Ca–Mg–HCO3) or magnesium–calcium–bicarbonate type (Mg–Ca–HCO3). Chemical analysis of all water samples shows that the mean cation concentrations (in mg/L) were in the order Ca2+ > Mg2+ > Na+ > K+ and that of anions are in the order \( \text{HCO}_{3}^{ - } \) > \( \text{SO}_{4}^{2 - } \) > Cl− > \( \text{CO}_{3}^{ - } \) for all groundwater and surface water samples. The Mg2+/Ca2+ ratio ranges from 0.21 to 1.30 with most of the values greater than 0.5, indicating that weathering of dolomites is dominant in groundwater. The analysis reveals that all of the samples are neutral to slightly alkaline (pH 7.0–8.7). Groundwater and surface water suitability for drinking usage was evaluated according to the World Health Organization and Turkish Standards (TSE-266) and suggests that most of the samples are suitable for drinking. Various determinants such as sodium absorption ratio, percent sodium (Na %), residual sodium carbonate and soluble sodium percentage revealed that most of the samples are suitable for irrigation. According to MH values, all of the well water samples were suitable for irrigation purposes, but 80 and 81.82% of Zillek springs and surface water samples were unsuitable. As per the PI values, the water samples from the study area are classified as Class I and Class II and are considered to be suitable for irrigation.

The role of gypsum and/or dolomite dissolution in tufa precipitation: lessons from the hydrochemistry of a carbonate–sulphate karst system

AbstractThe precipitation of freshwater carbonates (tufa) along karstic rivers is enhanced by degassing of carbon dioxide (CO2) downstream of karstic springs. However, in most karstic springs CO2 degassing is not enough to force the precipitation of tufa sediments. Little is known about the role of dissolution of gypsum or dolomite in the hydrochemistry of these systems and how this affects the formation of tufa deposits. Here we present a monitoring study conducted over a year in Trabaque River (Spain). The river has typical karst hydrological dynamics with water sinking upstream and re‐emerging downstream of the canyon. Mixing of calcium–magnesium bicarbonate and calcium sulphate waters downstream of the sink enhances the dissolution of carbonates and potentially plays a positive role in the formation of tufa sediments. However, due to the common‐ion effect, dissolution of dolomite and/or gypsum causes precipitation of underground calcite cements as part of the incongruent dissolution of dolomite/dedolomitization process, which limits the precipitation of tufa sediments. Current precipitation of tufa is scant compared to previous Holocene tufa deposits, which likely precipitated from solutions with higher saturation indexes of calcite (SIcc values) than nowadays. Limited incongruent dissolution of dolomite/dedolomitization favours higher SIcc values. This circumstance occurs when waters with relatively high supersaturation of dolomite and low SO42− composition sink in the upper sector of the canyon. In such a scenario, the process of mixing waters enhances the exclusive dissolution of limestones, preventing the precipitation of calcite within the aquifer and favouring the increase of SIcc values downstream of the springs. Such conditions were recorded during periods of high water level of the aquifers and during floods. This research shows that the common‐ion effect caused by the dissolution of gypsum and/or dolomite rocks can limit [or favour] the precipitation of tufa sediments depending on the occurrence [or not] of incongruent dissolution of dolomite/dedolomitization. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Characterization of crystalline structures in Opuntia ficus-indica.

This research studies the crystalline compounds present in nopal (Opuntia ficus-indica) cladodes. The identification of the crystalline structures was performed using X-ray diffraction, scanning electron microscopy, mass spectrometry, and Fourier transform infrared spectroscopy. The crystalline structures identified were calcium carbonate (calcite) [CaCO3], calcium-magnesium bicarbonate [CaMg(CO3)2], magnesium oxide [MgO], calcium oxalate monohydrate [Ca(C2O4)•(H2O)], potassium peroxydiphosphate [K4P2O8] and potassium chloride [KCl]. The SEM images indicate that calcite crystals grow to dipyramidal, octahedral-like, prismatic, and flower-like structures; meanwhile, calcium-magnesium bicarbonate structures show rhombohedral exfoliation and calcium oxalate monohydrate is present in a drusenoid morphology. These calcium carbonate compounds have a great importance for humans because their bioavailability. This is the first report about the identification and structural analysis of calcium carbonate and calcium-magnesium bicarbonate in nopal cladodes, as well as the presence of magnesium oxide, potassium peroxydiphosphate and potassium chloride in these plants. The significance of the study of the inorganic components of these cactus plants is related with the increasing interest in the potential use of Opuntia as a raw material of products for the food, pharmaceutical, and cosmetic industries.

Reconnaissance on the suitability of the available water resources for irrigation in Thakurgaon District of northwestern Bangladesh

Reconnaissance on the suitability of the available groundwater resources for irrigation in Thakurgaon District of northwestern Bangladesh was done by determining pH, TDS, EC, hardness, alkalinity, major cations and anions. The pH values suggest that the water is slightly acidic to strongly basic. The dominant cation and anion in the study area are Ca2+, Mg2+ and HCO3−, respectively. Calcium bicarbonate, calcium–magnesium–bicarbonate and calcium carbonate are the dominant hydrochemical facies among the water samples. The groundwater system in the study area may be recharged through infiltration of rain. The above statement is further supported by Gibbs plot where most of the samples fall within the rock-dominance zone. The evolution of these waters may be controlled by precipitation and dissolution of carbonate minerals. The USSL, SAR–EC classification schemes and Wilcox plot confirm that the groundwater samples are good to excellent as irrigation water. However, the groundwater evolution in this study is mainly the result of weathering of carbonate minerals and cation exchange within the aquifer materials, confirming the shallow porous groundwater hydrochemistry characteristics.