The aquifers in the M’léta Plain are crucial for supplying drinking water and supporting industrial and agricultural water needs. However, they are facing a pollution risk and environmental degradation. The present study aims to assess the groundwater quality in the M’léta Plain, focusing on its physicochemical properties, statistics of the aquifer, pollution risks, and factors influencing the water mineralisation process. The analysis of 16 samples reveals that the water contains high levels of sulphates and chlorides, often accompanied by sodium, calcium, or magnesium. This suggests two distinct water types or facies: one characterised by sodium chloride or calcium chloride, and the other with calcic or sodic sulphate waters, sometimes including magnesium sulphate. These facies may be attributed to the influence of different formations at the outcrop. Statistical analyses reveal a strong correlation between electrical conductivity and the majority of chemical elements, indicating the impact of freshwater interacting with the underlying rock formations on mineralisation. Some results also show undersaturation of certain minerals. Furthermore, the study evaluates the water's suitability for irrigation in the M’léta Plain in accordance with Richards’ classification.
The karst springs of Tezbent Plateau were studied to gain insight into the hydrogeological and hydrodynamic behaviour of this karstic system. Four springs and six domestic wells were analysed for hydrogeochemical constituents, δ18O, and δ2H from September 2021 to June 2022. The Tezbent mountain range, located in northeastern Algeria, drains carbonate aquifers through several significant karst springs. The physical and chemical characteristics of water samples were analysed in order to assess the groundwater origins and identify the factors influencing its geochemical composition. Ionic speciation and mineral dissolution/precipitation were calculated. It was found that geology, specifically the presence of carbonate formations, elevation, and the rate of karst development, are the primary factors influencing groundwater composition and seasonal variations. The carbonate chemistry serves as a diagnostic indicator of karst development effects. The interaction between groundwater and surrounding host rocks is believed to be the primary process influencing the observed chemical characteristics of groundwater in the study area. The δ18O and δ2H values of groundwater samples indicate the meteoric origin of the groundwater recharge and suggest a minimal evaporation impact on the isotopic composition.
Water resources are facing significant challenges in result of rapidly growing demand, deteriorating quality, and the effects of climate change. Today, water quantity and quality issues have become prevalent in various regions across the globe, affecting both northern and southern territories. Among the sectors reliant on this resource, irrigation stands out as the largest consumer of water. When surface water becomes inaccessible due to insufficient precipitation or other factors, the use of groundwater becomes the only viable alternative for irrigation. The Remila Plain (Khenchela) is located in an endorean watershed in northeastern Algeria and extends over 250 km2 in a synclinal basin filled with water from the Mio-Plio Quaternary - the main aquifer of the region, widely used for irrigation. The aim of this work is to study the hydrochemistry of these waters, as well as the evolution of mineralisation, the identification of the origin of the chemistry, and the suitability of these waters for irrigation. Initial results indicate an evolution of mineralisation in the direction of groundwater flow, with electrical conductivity values varying between 1000µS/cm in the recharge zones, and 2700µS/cm at the outlet. This mineralisation is mainly due to the dissolution of evaporitic minerals and the alteration of silicates. In addition, the various water quality indices used indicate that the water can be used for irrigation without major risk to plants and soils.
This study analyzes the effects of dry land salinity, climate severity, and pollution on groundwater quality in the Middle Moulouya basin. Our research provides insights into certain pollutants and their sources and discusses the impact of saline soil and dry weather. A comprehensive understanding of these factors is essential for managing water resources and promoting sustainable resource use in the area. In fact, the use of a database relating to the major elements, viz. potassium (K+), calcium (Ca2+), sodium (Na2+), magnesium (Mg2+), bicarbonates (HCO3-), sulfates (SO42-, nitrates (NO3-), chlorides (Cl-) has proved to be effective to assess the hydrochemical features of groundwaters and their suitability for both aims (i.e., irrigation and drinking). The Middle Moulouya basin’s subterranean water is slightly acidic to basic, with a pH range of 6.8 to 7.66 and mild to brackish water at specific sites. Furthermore, in line with the hydrochemistry diagrams, groundwater can be classified into three main types: Ca-Cl, Ca-HCO3, and Ca-Mg-Cl type. Moreover, the results pertaining to the overall quality of groundwater regarding Moroccan control standards guidelines indicate that: (i) 32.43% of the groundwater samples are of excellent quality, (ii) 24.32% of the collected water points are of good quality, (iii) 32.43% have medium quality, (iiii) and only 10.82% are of poor and very poor quality (i.e., 5.41% for each class). Finally, based on the Wilcox method, a significant percentage of groundwater sites are suitable for farming.
In Algeria, groundwater frequently serves as a main source of drinking water supply. Given the country’s geographical characteristics and water resource availability, many municipalities rely on groundwater to meet their drinking water needs.In this study, the quality of groundwater for drinking purposes in the northern region of the Middle Sébaou was assessed by obtaining hydrochemical data from ten groundwater samples in 2019. The study aimed to analyze and evaluate the hydrochemical composition of the groundwater using multivariate analysis and the water quality index (WQI) to determine its suitability for human consumption. Statistics showed that most of the groundwater analysis parameters are within acceptable limits except calcium (Ca2+) and bicarbonates (HCO3−) which exceed the potability standards set by the guidelines of the World Health Organization (WHO) for drinking water. Piper diagram demonstrates the existence of two hydrochemical facies: bicarbonate calcium and magnesium, and chloride as well as sulfate calcium and magnesium. According to the WQI values obtained in this study, ranging from 53.32 to 71.18, all of the groundwater samples exhibit good water quality based on the classification of the WQI method. On the basis of these results, the groundwater of the northern region of the Middle Sébaou is suitable for drinking purposes.
Knowledge of the quantity and quality of groundwater is a prerequisite to encourage investment in the development of a region and to consider the sedentarisation of populations. This work synthesises and analyses data concerning the chemical quality of the available water acquired in the Foum el Gueiss catchment area in the Aures massif. Two families of waters are observed, on the one hand, calcium and magnesian chlorated-sulphate waters and on the other hand, calcium and magnesium bicarbonate waters. Multivariate statistical treatments (Principal Component Analysis – PCA and Discriminant Analysis – DA) highlight a gradient of minerality of the waters from upstream to downstream, mainly attributed to the impact of climate, and pollution of agricultural origin rather localised in the lower zones. These differences in chemical composition make it possible to differentiate spring, well and borehole waters. The main confusion is between wells and boreholes, which is understandable because they are adjacent groundwater, rather in the lower part of the catchment area. The confusion matrix on the dataset shows a complete discrimination with a 100% success rate. There is a real difference between spring water and other samples, while the difference between wells and boreholes is smaller. The confusion matrix for the cross-validation (50%).
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The present study attempts to investigate physicochemical features and evaluate quality of collected ground water samples from benchmark locations in Fazilka district, southwestern (SW) side of the Punjab. The samples of groundwater (GW) as well as soil were collected from different locations and examined for pH, electrical conductivity (EC), carbonates (CO3 2 ), bicarbonates (HCO3 −), chlorides (Cl−), magnesium (Mg2+), calcium (Ca2+), sodium (Na+), sulfate (SO42−) and potassium (K+). The appropriateness of water for drinking was checked using water quality index (WQI), while indices like soluble sodium percentage (SSP), sodium adsorption ratio (SAR), residual sodium carbonate, magnesium hazard, permeability index and Kelly’s ratio were investigated for appraisal of irrigation water quality. Samples are statistically tested using two-way ANOVA and principal component analysis (PCA) to extract correlation between water parameters. Most of the samples were under high to low (C3S1), high to medium (C3S2) and very high to high (C4S3) based on US Salinity Laboratory (USSL). On the base of RSC, samples were under safe to unsuitable category. For hydrochemistry analysis, the piper diagram indicates that water samples were mixed type and Ca-Mg-HCO3 type. Study indicated that water with high salinity was used for irrigation of crops and it has adverse effects on the soil quality and crop yield is of concern for future.
The fractured groundwater aquifers, predominantly found in South Africa, show varying groundwater chemical characteristics in various locations. The hydrochemistry of groundwater is affected by the weathering of rock formations in contact and anthropogenic activities. Determination of groundwater chemistry is important for aquifer protection and overall groundwater management. A hydrochemical analysis is a useful tool for identification of water types, chemical composition, its suitability for specified purposes, and an important requirement for water use licensing applications. The hydrochemical data of groundwater from 79 boreholes near Leliefontein, Kamiesberg local municipality of South Africa, were analysed, using integrated statistical, geostatistics and spatial interpolation methods. The result shows Na+ and Cl− to be the abundant cation and anion. The mean concentration of Na at Leliefontein was 267.39 mg/l, and that of Cl was 574.81 mg/l. The ionic concentrations in groundwater was in sequence of Cl− > Na+ > HCO3− > SO42− > Ca2+ > Mg2+ > NO3− > Si > K+ > F-. The analysis indicated that the cation exchanges in groundwater are influenced by limited silicate weathering, with calcite and dolomite dissolution. Geostatistical and spatial analysis interpolation for the major cation (Na) and major anion (Cl), Sodium Adsorption Ratio (SAR), Electrical Conductivity (EC) and Water Quality Index (WQI) was performed using Inverse Distance Weighing method. The hydrochemical data for the Leliefontein groundwater were analysed to classify water for domestic use (drinking) and agriculture (irrigation) purposes, based on the recommended guidelines of the South African National Standard (SANS). The study area was characterised by high salinity of three water types, viz, Na-Cl seawater type, Ca-Cl reverse ion-exchange water type, and Na-HCO3 base ion-exchange water types. About 70–80% of the boreholes in Leliefontein met the requirement for irrigation application for Sodium Adsorption Ratio (SAR) and salinity hazard analysis, while the groundwater generally required further treatment before domestic use.
With a flow estimated at 1200 m3∙s–1 and a height of 8 m downstream, the flood that occurred on October 10, 2008 spread along the M’zab River over a length of more than 180 km. Material and human damage is visible, but its effects on the quality of the waters of the alluvial layer remain unknown: this is the purpose of this paper. Samples of groundwater were taken during the period 2005–2012 in 4 oases of the valley. Physicochemical analyses were performed using molecular and flame spectroscopic methods and also volumetric methods on water samples. The results obtained were interpreted using histograms and hydrochemical diagrams, such as the Avignon software (L.H.A) (version 4, 2008). Low effect of flood on the water quality of the alluvial aquifer was manifested by concentrations of magnesium sulphate and calcium chloride. On the other hand, there is an accumulation of salts infiltrated by sewage except for the zone of Bouchen. The diagrams show that there is an improvement in water quality in this area.
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Osiągając przepływ szacowany na 1200 m3∙s–1 i wysokość fali 8 m, powódź, która wystąpiła 10 października 2008 r., objęła swoim zasięgiem 180 km biegu rzeki M’zab. Straty ludzkie i materialne są znane, ale wpływ powodzi na jakość wody poziomów aluwialnych pozostaje nierozpoznany i dlatego stał się celem niniejszych badań. Próbki wód gruntowych pobierano w latach 2005–2012 w czterech oazach w dolinie rzeki. Próbki zostały poddane analizom fizycznym i chemicznym. Otrzymane wyniki interpretowano z wykorzystaniem histogramów i diagramów hydrochemicznych opracowanych za pomocą oprogramowania Avignon (L.H.A), wersja 4, 2008. Stężenie siarczanu magnezu i chlorku wapnia dowodziło niewielkiego wpływu powodzi na jakość wód aluwialnych poziomów wodonośnych. Z wyjątkiem strefy Bouchen, stwierdzono jednak akumulację soli infiltrujących ze ściekami. Na podstawie wyników badań można zaobserwować poprawę jakości wody na badanym obszarze.
Groundwater is a key source of drinking water in Jordan. This study was conducted to assess the suitability of groundwater in major groundwater basins in Jordan for drinking purposes. The groundwater quality data from sixteen sampling stations within one-year-monitoring period from March 2015 to February 2016 were used. Weighted arithmetic water quality index (WQI) with respect to the Jordanian standards for drinking water was used for quality assessment. Sixteen Physical, chemical and microbiological parameters were selected to calculate WQI. The result showed that all physical and chemical parameters were almost below the maximum allowable level based on the Jordanian standards for drinking. On the other hand, the microbiological parameter (i.e. E.coli count) was exceeded the maximum allowable limit in all the studied locations based on the Jordanian standards for drinking water. The computed WQI values range from 40 to 4295. Therefore, out of 16 studied locations, three locations are classified in the “Excellent water” class, nine locations as a “Good water” class, one as a “Poor water” class, two as a “very poor water” class, and one as a “water unsuitable for drinking purpose” class. Furthermore, Escherichia coli is considered the most effective parameter on the determination of WQI in this study. This result highlighted the importance of including the microbiological parameters in any drinking water assessment, since they reflect with other physical and chemical parameters the actual condition of water quality for different purposes.
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In arid areas, with rivers functioning episodically, alluvial resources are the main source of water. Considering the intensified regulation of discharge in montane catchments, supplying the intermittent rivers, in the nearest future alluvial aquifers will gain key importance for the functioning of people in arid zones. The research aimed to investigate the diversified chemistry of alluvial waters typical of large intermittent river valleys in hot arid zones as well as to analyse processes determining the water chemistry and affecting its diversity. The detailed study, carried out in October 2015, covered the Draa river valley (1100 km total length) in the region of the Mhamid Oasis. The examined water was sampled from all wells found in the study area. Concentrations of the main cations: Ca2+, Mg2+, K+, Na+, NH4+, and Li+, anions: Cl−, SO42−, HCO3−, and NO3−, as well as trace elements: Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn, were identified. Results were analysed with statistical, hydrochemical, and geochemical modelling methods. Alluvial waters of the eastern and western part of the oasis differed in concentrations of numerous components, what resulted from the regulation of irrigation. Specific electrical conductivity showed a 3.5-fold increase, from 3800 to 13800 μS/cm, consistent with the direction of water flow in the oasis, from east to west. Even a greater rise was observed for ions: Cl− (6x), Na+ (5.5x), Mg2+ (5.0x), Ca2+, and SO42− (3.5x). Such a composition indicated multiionic hydrochemical type of waters dominated by Na+ and Cl−. Additionally, high Pearson correlation coefficients were recorded for Na+ and Cl− (0.98) as well as Mg2+ and Cl− (0.97). The saturation index suggested that the main water components originated from dissolving of minerals such as halite, anhydrite, sylvite, and gypsum. Groundwater chemistry in the Mhamid Oasis was determined mainly by geogenic processes, such as dissolving of evaporates, precipitation of carbonate minerals, and ion exchange.
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The purpose of the study was to determine quantitative and qualitative changes in the waters of Lake Jamno in northern Poland due to the presence of new hydrotechnical structures in its drainage basin, with a special focus on the effects of a new storm barrier. The study consisted primarily of a review of measurement data, historical records and fieldwork prior to the construction (2002–2008) and following the construction of the storm barrier (2015). Fieldwork included hydrographic surveys and water sampling for laboratory analysis. The main and most easily discernible effect of the construction is the change in water quality in Lake Jamno. This is particularly true in the case of key indicators related to seawater, including conductivity, whose values changed from brackish to fresh water.
The source of chemical constituents in the groundwater and the source of inrush water are two important issues related to the hydrochemical evolution and safety of coal mining in coalfield of China, respectively. In this study, major ion concentrations of thirty-four groundwater samples from three representative aquifers in northern Anhui province, China have been analyzed by a series of statistical methods for tracing the sources of major ions and inrush water. The differences of major ion concentrations in groundwater from different aquifers indicate that they have undergone different types and degrees of water rock interactions, and provide the possibility for water source identification based on major ions. Factor analysis has identified two potential sources responsible for the major ion concentrations of the groundwater, including dissolution of carbonates and evaporates and the weathering of silicate minerals, which was further confirmed by the Unmix model analysis. Discriminant analysis can classify the sources of groundwater with high efficiency, similar to the results obtained based on the source contributions of the Unmix model analysis. In summary, different with those of factor and discriminant analysis, the Unmix model analysis can provide information about source of major ions and water simultaneously.
This study is a contribution to the knowledge of hydrochemical properties of the groundwater in Fesdis Plain, Algeria, using multivariate statistical techniques including principal component analysis (PCA) and cluster analysis. 28 samples were taken during February and July 2015 (14 samples for each month). The principal component analysis (PCA) applied to the data sets has resulted in four significant factors which explain 75.19%, of the total variance. PCA method has enabled to highlight two big phenomena in acquisition of the mineralization of waters. The main phenomenon of production of ions in water is the contact water-rock. The second phenomenon reflects the signatures of the anthropogenic activities. The hierarchical cluster analysis (CA) in R mode grouped the 10 variables into four clusters and in Q mode, 14 sampling points are grouped into three clusters of similar water quality characteristics.
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Przedstawione w niniejszej pracy badania stanowią przyczynek do poznania właściwości hydrochemicznych wód gruntowych na równinie Fesdis w Algierii uzyskany z wykorzystaniem wieloczynnikowej analizy statystycznej, w tym analizy głównych składowych (PCA) i analizy skupień. Dwadzieścia osiem próbek wody pobrano w lutym i w lipcu 2015 r. (po 14 próbek w każdym miesiącu). Na podstawie analizy składowych głównych zastosowanej do zbioru danych stwierdzono cztery istotne czynniki, które objaśniały 75,19% całkowitej wariancji. Metoda PCA umożliwiła wyodrębnienie dwóch zjawisk odpowiedzialnych za mineralizację wody. Głównym czynnikiem tworzenia jonów w wodzie jest kontakt wody ze skałą (czas retencji mineralizacji). Drugi czynnik jest odzwierciedleniem aktywności człowieka. W hierarchicznej analizie skupień (CA) zgrupowano 10 zmiennych w cztery skupienia w trybie R, a w trybie Q zgrupowano 14 stanowisk pobierania próbek w trzy skupienia o podobnych cechach jakości wody.
Béchar region is located in the southwest of Algeria, characterized by an arid climate with a Saharan tendency. It is subject to an increasing demand for water like all the great agglomerations due to the economic and demographic development. The groundwater of region is deteriorating because of the economic development, and the rapid growth of population. This article is devoted to the study of hydrochemistry and processes of mineralization of groundwater in this region. The results of physicochemicals analyses shows the same chemical facies of the chloride and sulphate-calcium and magnesium type, with high mineralization from North-East to South- -West to the outlet of Béchar–Kénadsa basin. The determination of the mineralization origin and the main major elements were approached by multivariate statistical treatment and geochemical. This method has identified the main chemical phenomena involved in the acquisition of mineralization of water in this aquifer. These phenomena are mainly related to the dissolution of evaporite formations, the infiltration of runoff water and direct ion exchange and mixing. However, the high mineralization anomaly is observed at the centre of Béchar–Kénadsa basin progressively by going to the outlet of this basin.
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Region Béchar w południowozachodniej Algierii charakteryzuje klimat suchy z wpływami saharyjskimi. Jak wszystkie duże aglomeracje, region ten wykazuje rosnące zapotrzebowanie na wodę w związku z rozwojem ekonomicznym i demograficznym. Rozwój gospodarczy i szybki przyrost populacji jest powodem pogarszania się jakości wód gruntowych. Niniejszy artykuł jest poświęcony badaniom właściwości hydrochemicznych i procesów mineralizacji wód gruntowych w regionie. Wyniki analiz wykazują występowanie podobnych facji chemicznych typu chlorkowego i siarczanowo-wapniowych lub magnezowych o wysokim stopniu mineralizacji od północnego wschodu do południowego zachodu basenu Béchar–Kénadsa. Źródła mineralizacji i główne pierwiastki zostały oznaczone metodami geochemicznymi z zastosowaniem wieloczynnikowej analizy statystycznej. Metody te dały podstawy do identyfikacji głównych zjawisk chemicznych wpływających na mineralizację wody, takie jak rozpuszczanie formacji ewaporytowych, infiltracja spływów powierzchniowych, bezpośrednia wymiana jonowa i mieszanie. Anomalię wysokiej mineralizacji malejącą w kierunku odpływu zaobserwowano w środkowej części basenu Béchar–Kénadsa.
Groundwater samples from Turonian aquifer of Béchar region were evaluated as drinking and irrigation water sources. physicochemical parameters including pH, EC, TH, Na+, Ca2+, Mg2+, Cl–, SO4 2– and NO3 – were determined for 16 water sampling points. These characterizations show that the groundwater is fresh to brackish, slightly alkaline and the major ions are Na+, Ca2+, Mg2+, Cl– and SO4 2–. According to WHO standards, 50% of the analysed water are suitable as a drinking source while the other samples are not in compliance with drinking water standards. This non-compliance is basically due to the high concentrations of Na+, Cl–, and SO4 2– requesting further treatment to reach the stringent standards. According to the results of nitrate concentrations, anthropogenic source seems to influence the groundwater quality. The present study shows that Béchar groundwater may represent an important drinking and irrigation water source. However, a specific management strategy should be adapted in order to avoid the contamination by anthropogenic sources.
PL
Oceniano przydatność wód gruntowych z wieku/piętra turonu w regionie Béchar do nawadniania i zaopatrzenia ludności w wodę pitną. W próbkach wody z 16 stanowisk oznaczano pH, przewodność elektrolityczną (EC), całkowitą twardość (TH), Na+, Ca2+, Mg2+, Cl–, SO4 2– i NO3 –. Analiza wykazała, że wody gruntowe są słodkie do słonawych, alkaliczne, a głównymi jonami są: Na+, Ca2+, Mg2+, Cl– i SO4 2–. Według norm WHO 50% analizowanych próbek spełnia wymogi stawiane wodzie przeznaczonej do picia. W pozostałych próbkach zbyt duże stężenie Na+, Cl– i SO4 2– wskazuje na konieczność uzdatniania wody, aby osiągnęła ona wymagane standardy. Stężenie azotanów wskazuje na antropogeniczne źródło zanieczyszczenia tymi jonami. Badania dowodzą, że wody gruntowe Béchar mogą być źródłem wody do nawadniania i do celów spożywczych. Należy jednak przyjąć szczególną strategię gospodarowania wodą, aby uniknąć zanieczyszczenia ze źródeł antropogenicznych.
Drilled wells during their operation are subject to so-called “aging” processes, which is visible in the decrease of their efficiency and increase in depression. The process, especially in case of quaternary and tertiary waters, is most affected by the chemical colmatation of the filter and filter-adjacent zone with chemical compounds precipitated from the flowing water. The literature analysis shows that ferrous sediments are the main mass of sediments clogging the quaternary and tertiary water intakes. They are usually in the form of soft reddish-colored sediments, and their essential element is Fe2O3 and FeO. Iron, siderite and quartz hydroxides were also found. The degree of colmatation in such wells can be significantly reduced by frequent renovations with chemical methods. The article presents results of laboratory tests on dissolution of sediments clogging withdrawal well filters with sodium dithionite (Na2S2O4) and sodium pyrosulphite (Na2S2O5). Representative samples were taken from selected quaternary water intakes in northern Poland.
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The paper is based on the hypothesis that coastal lakes significantly affect changes in the quality of freshwater coming from catchments, which is best reflected in the reduction of biogenic loads. Some of the main reasons for this phenomenon include unique geographic locations of coastal lakes and physical and chemical properties of their waters as well as other hydrographic determinants that affect water circulation in catchments. The study area covered the direct drainage basin of Lake Łebsko, which is located in Słowiński National Park in northern Poland, on the coast of the southern Baltic Sea. The study was conducted from June 2008 to October 2010. Fieldwork was the main part of the research project and included hydrographic mapping, water sampling for laboratory analysis, and measurement of the discharge in all tributaries and outflows of the studied lake. Water chemistry data for Lake Łebsko indicate a significant accumulation of biogenic materials in the lake, which proves a strong effect exerted by the lake on the incoming water. This is true for both total chemical loads per year as well as concentrations of selected ions over short time intervals. This standard pattern may be interrupted by seawater intrusions that alter water chemistry in the whole lake.
W artykule przedstawiono charakterystykę hydrograficzno-hydrochemiczną źródeł z wytraceniami martwic wapiennych położonych na obszarze Beskidu Małego. Źródła tego typu wraz z charakterystycznymi zbiorowiskami Cratoneurion commutati zaliczone zostały do siedlisk przyrodniczych o znaczeniu priorytetowym (kod Natura 2000: 7220). Wykazano, że depozycja martwic wapiennych zachodzi w źródłach o zróżnicowanej mineralizacji wód. Ma ona również charakter okresowy, przypada głównie na lato.
EN
The paper presents hydrological-hydrochemical characteristics of springs with limestones precipitations situated in the area of the Beskid Mały Mts. These springs with characteristic plant communities Cratoneurion commutati were included to priority NATURA 2000 habitat (code 7220). It was revealed that precipitation of limestone occurs in spring with diversified mineralization of waters. It is a periodic phenomenon with the maximum of the occurrence in summer.
The mineral framework and pore waters of glacial sediments exposed in the foreland of Weren- skioldbreen in SW Spitsbergen were sampled and analyzed to model the evolution of pore water chemistry, representing the advancement of weathering in a chronosequence. Three samples were taken at distances representing snapshots of approximately 5, 45 and 70 years of exposure. Complementary mineralogical analyses of the mineral framework and chemical analyses of pore waters, coupled with thermodynamic modelling of mineral-water interactions were applied. Recently uncovered sediments of the bottom moraine underwent very little weathering underneath the glacier cover; both the sediments and pore waters in the forefield of the Werenskioldbreen represent a very immature system. Poorly sorted sediments were deposited by the glacier and not reworked by fluvioglacial waters. The ratio of ‘amorphous iron’ to ‘free iron’ Feo/Fed increases with distance from the glacier terminus from 0.30 through 0.36 to 0.49, typical for fresh glacial till. The increase in saturation with CO2 (from p(CO2) –3.8 to –2.4) and the concentration of all major ions in pore waters (from 123 to 748 mg/L total dissolved solids, TDS) was observed in this young chronosequence. The waters evolved from carbonate- dominated to sulphate-dominated, indicating that with progress in weathering the dominating processes are equilibration with carbonates, oxidation of sulphides and the influence of gypsum precipitation by seasonal freeze-thaw cycles. Mass balance calculations and inverse modelling of the composition of pore waters, verified by microscopic observations of alteration on the surfaces of mineral grains, allowed thermodynamic confirmation of the fact that the relative significance of carbonate weathering decreases and that of sulphate increases down the chronosequence. The participation of silicate minerals in weathering is low, indicating a relatively immature stage of weathering within this particular chronosequence. It is significant that the morphology of etch pits and the formation of secondary phases apparent on mineral surfaces were identical, regardless of the distance from the glacier terminus. This might indicate that the mechanisms of particular weathering processes at the mineral-water interface are the same at the initial as well as at the more mature stages and do not change at least within ca. 70 years of exposure.
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