Composition Of Mineral Waters Research Articles

Predicting potential pollutant release from waste rock at the abandoned Beck mine (Karelia, Russia) by equilibrium kinetic modeling

The Beck mine, located in the Republic of Karelia, Russia, is an abandoned mining site with significant potential for environmental contamination due to the presence of potential pollutants in its waste rocks. In this study, we investigated the chemical composition of mine waters and waste rocks and developed a theoretical model to understand waterrock interactions and the release of potential pollutants. Water samples collected from various locations on the Beck mine property were analyzed for chemical composition and showed low concentrations of total dissolved solids with pH values ranging from 6.42 to 7.74. The chemical composition of natural waters was determined by ICP-MS, ICP-AES, ion chromatography, potentiometric titration, and spectrophotometry. Equilibrium kinetic modeling was used to simulate water-rock interactions. The model predicted the concentrations of major and trace elements, demonstrating that dissolutionprecipitation and complexation are the primary mechanisms shaping the chemical composition of mine waters. The dynamics of dissolution-precipitation of Fe-containing minerals highlighted the importance of the duration of water-rock interaction, with stagnant mine waters exhibiting higher concentrations of heavy metals. In addition, the presence of dissolved organic matter played a critical role in the accumulation of iron and arsenic in the studied mine waters. Overall, this study highlights the utility of equilibrium kinetic modeling in understanding the behavior of heavy metals during water-rock interactions and provides valuable insights into the potential environmental impacts of abandoned mine sites such as the Beck mine.

MAGNETIC MODIFICATION OF ION EXCHANGE PROCESSES

The method of ion exchange is widely used in modern water supply systems. Ion exchange units are used to correct the mineral composition of water to the required standards; wastewater treatment; desalination and softening of natural waters. Today, there are technical solutions to improve the process of water purification, softening and demineralization. They include: improvement of physical and chemical conditions; intensification of the ion exchange process; use of new ion exchange materials; modification of ion exchange resins; combination with other water treatment methods; modernization of equipment and designs of ion exchange devices. The paper investigates the effect of magnetic modification on the intensification of ion exchange processes during the adjustment of the mineral composition of natural waters. The obtained results demonstrate the influence of the magnetic field on the ion exchange process.

OPTIMAL CONDITIONS FOR LIME TREATMENT OF MINE WASTEWATER FROM POLYMETALLIC ORE MINES

Mine waters of polymetallic mines are multicomponent systems containing ions of heavy non-ferrous metals, calcium, magnesium, iron, ammonium, as well as chlorides, sulfates, fluorides and other components in a wide range of concentrations. As a rule, water purification of this type is carried out by the lime method, which provides a fairly high degree of extraction of the most toxic pollutants (metals), with relatively small material costs. Taking into account the large volume, complexity and variation of the composition of mine waters, the tasks of optimizing reagent consumption, methods of its supply and effective control of the purification process still do not lose their relevance. The article presents the results of laboratory studies to determine the optimal conditions for processing model solutions that provide the maximum degree of purification for specific conditions of the Irtysh mine (East Kazakhstan). Experimental data obtained on model solutions are confirmed by the results of purification of real mine waste water. The results of experiments with mine water confirmed that the selected pH region of 9.5–10.5 can be accepted as optimal, which will allow achieving a high degree of purification of mine water.

Understanding the Mechanisms and Implications of the First Flush in Mine Pools: Insights from Field Studies in Europe’s Deepest Metal Mine and Analogue Modelling

The chemical composition of mine water discharged from flooded underground mines typically improves over time. This phenomenon is called first flush and can be described by a characteristic curve. Shortly after the mine water begins to discharge, water constituent concentrations rise and then fall in an almost exponential curve, improving water quality over time. In this study, the change in mine water quality was investigated throughout the mine water body. This mine water body commonly consists of different water bodies with individual densities, resulting in mine water stratification. Anthropogenic disturbance of the mine water body can disrupt this stratification and also the positive effect of the first flush. To better understand and predict the first flush, the first flush was simulated experimentally using an analogue model of a flooded underground mine, the Agricola Model Mine. The results were compared with field studies to help understanding and predicting the change in mine water quality. Overall, the results suggest that the first flush occurs throughout the mine water body, making it similar to a chemical reactor. This better understanding of the process can lead to more effective mine water management and design of mine water treatment facilities.Graphical

Magnetic Modification of Ion Exchange Processes

Today, the ion exchange method is widely used in water treatment systems. Ion exchange systems are used to correct the mineral composition of water to the required standards; wastewater treatment; desalination and softening of natural waters. To present day, there are technical solutions to improve the process of water purification, treatment, softening and demineralization. They include: improvement of physical and chemical conditions; intensification of the ion exchange process; use of new ion exchange materials; modification of ion exchange resins; combination with other water treatment methods; modernization of equipment and designs of ion exchange devices. In order to improve the flow conditions and reduce the burden on the environment, it is promising to implement technologies aimed at intensifying the ion exchange process by activating the components of the process. The paper investigates the effect of magnetic modification on the intensification of ion exchange processes during the adjustment of the mineral composition of natural waters. The obtained results demonstrate the influence of the magnetic field on the ion exchange process.

Wastes in Underground Coal Mines and Their Behavior during Mine Water Level Rebound—A Review

Backfill materials of various origin and composition, abandoned machinery, oils, PCB, gallery support material and cables are the main wastes occurring in underground coal mines during the period of their abandonment. Bearing in mind that under increasing societal pressure most if not all underground coal mines are going to close sooner rather than later, it is important to understand the interactions of these waste materials with rising mine water during mine water level rebound to prevent adverse environmental effects, especially on surface and groundwater. To this end, the composition of mine water at decant points as well as the hydrogeochemical, temporal and spatial dynamics of mine water during rebound requires quantification. In the first part of this paper, an overview of waste materials in underground coal mines is presented. The second part focusses on the experiences gained in the Ruhr area, a closed underground coal mining region in western Germany, where mine water rebound has been ongoing for decades. In this regard, the mine water modeling program Boxmodell was applied during regulatory approval procedures to predict the hydrodynamics and hydrogeochemical development of the water rebound. The results of these investigations allow deep insights into the interactions of rising mine water with wastes as well as the complex chemical evolution of mine water and potentially occurring contaminants (e.g., PCB). The experiences regarding wastes in underground coal mines and the geochemical evolution of rising mine water gained in the Ruhr area can be utilized to support the planning of mine closure in currently still active underground coal mining areas worldwide.

Comparative Evaluation of the Feasibility of Utilizing the Bakken Formation Oil and Gas Field Produced Water for Extraction of Critical Minerals and Salts, with a Focus on the Inyan Kara Formation: An Analysis of Salinity and Infrastructure

This study compares the salt concentration and mineral composition of water from the Bakken Formation and the Inyan Kara Formation to assess their suitability for salt/critical minerals extraction. The results reveal that the Bakken Formation exhibits significantly higher levels of dissolved solids, calcium, magnesium, and chloride compared to the Inyan Kara Formation, indicating its potential suitability for salt/critical elements extraction. Conversely, the Inyan Kara Formation water displays higher bicarbonate concentrations, which may limit its applicability in certain salt extraction processes. The Bakken Formation proves more viable for water production due to its existing oil and gas infrastructure and abundant produced water from active and abandoned oil wells. This availability of produced water wells reduces the cost of critical mineral extraction and presents opportunities for water reuse or critical minerals sale, generating additional revenue that could offset recycling and disposal costs. In contrast, the absence of water production wells in the Inyan Kara Formation hinders its economic feasibility for salt/mineral extraction. The Inyan Kara Formation has a higher volume of water, but its lower salt content limits its usefulness for some purposes, especially in the energy industry for recovering rare earth minerals. Considering the higher mineralization, the concentration of key ions, and the presence of water production infrastructure, the Bakken Formation emerges as a more favorable choice for critical mineral extraction. However, factors like environmental impact and extraction costs should be considered in determining the most suitable formation. Despite data limitations, the study utilizes a valuable database to identify regional variations in salt concentrations for critical mineral extraction.

Formation of mine drainage in the Far Eastern region and its impact on the ecosphere and public health

The long-term development of the mining industry in the Komsomolsky, Kavalerovsky and Dalnegorsky districts of the Far East of Russia caused origination of large-scale mining technogenic systems. During the period of socalled “perestroika”, mining production in the region was suspended, while mine workings (pits, adits) and tailings dumps were not subjected to any kind of preservation or reclamation. Only the boron and lead-zinc mining sectors in the Dalnegorsk district are currently in operation. The purpose of this paper is to assess the composition of mine waters, reveal the conditions of their formation, the presence of various aqueous species (coordination compounds and ions) of different elements and establish the parameters of precipitation of a number of hypergenic natural and technogenic minerals from these waters. This paper provides the hydrochemical characteristics of mine waters in the mining technogenic systems of tin-sulfide, copper-tin, tin-polymetallic, and polymetallic deposits, indicates the conditions of their formation and describes the adverse impact on the hydrosphere, as well as on human health in these districts. The studies of sulfide oxidation and mine water formation processes were carried out by the method of physicochemical simulation involving the use of the Selektor software package. The Eh–pH parameters of solutions, their composition with respect to stable aqueous species (complex compounds and simple ions), paragenetic associations (paragenesis) of precipitating hypergenic minerals with respect to the primary composition of ores and host rocks were established in a wide temperature range (from −25 to +45 °С). It has been established that the simulated micropore solutions participating in the formation of mine waters exhibit a wide range of Eh–pH parameters: Eh from 0.55 to 1.24 V and pH from 0.3 to 13.8. The technogenic minerals Fe, Cu, Zn, Pb and Sb belonging to oxide and hydroxide, sulphate, and arsenate classes are precipitated from them. Mine waters of high concentration, prior to and after the precipitation of technogenic minerals (weight of which reaches the hundreds of grams), are released into the hydrosphere. The simulated solutions contain all the elements of sulfide ores: Cu, Zn, Pb, Fe, Ag, As, Sb and S, whereas their concentrations in the form of aqueous species reach the tens of grams, while under cryogenic conditions the concentrations are by one or two orders of magnitude higher as a result of ice formation. The forms of migration of the elements depend on the temperature conditions. The negative impact of mine waters on the region hydrosphere and human health was demonstrated. In the districts under consideration, obvious trend of increasing morbidity (for almost all types of diseases) by 2 times both in adults and in children as compared to other Far Eastern regions was revealed. In addition, the morbidity of the child population for almost all the diseases under consideration proved much higher than in adults.

Determination of Key Quality Indicators for Organization of Potable Water Source Monitoring under Changing Climatic Conditions

Background: In the context of deteriorating surface water quality, it is important to create a monitoring system to control constantly changing indicators that can affect the quality of both natural and potable water supplied to the population. Organic carbon is one of the key indicators reflecting the rate of production and destruction, climate change and anthropogenic impacts, safety and efficiency of potable water treatment. Objective: To study key indicators in the organization of potable water source quality monitoring. Materials and methods: In 2020–2021, monthly water sampling was carried out in a reservoir serving as the source of household and potable water supply of a large industrial city of the Sverdlovsk Region, and after water treatment. Water temperature, dissolved total, organic, and inorganic carbon, pH, the permanganate index (PI), hardness, and dry residue were measured. We then analyzed correlations between the indicators and assessed the efficiency of water treatment. Results: Maximum concentrations of Ctotal (54.3 mg/dm3) and Corg (36.0 mg/dm3) in the source water were found in January 2021. The predominance of Cinorg concentrations compared to Corg was mainly observed in warm months of the year. Water treatment generally decreased the content of Ctotal in potable water by 12–32 %, Corg by 12–47 %, Cinorg by 6–32 %, and PI by 28–68 %, except for a few months. In spring and summer 2021, we noted a decrease in PI in the reservoir; compared to other seasons, an increase in water pH was revealed in summer. We established a negative correlation between concentrations of organic carbon and water temperature. Conclusions: Monitoring studies of the surface potable water source have been organized. We revealed seasonal patterns of carbon changes and indicators of the mineral composition of water, and demonstrated the efficiency of water treatment.

Use of analysis of seasonal hydrochemical regime for better understanding of mine water genesis and more accurate estimate of its impact on stream water quality at flooded Rudňany ore mine

Seasonal hydrochemical regime of water flowing out of the Rochus Fe-Cu mine in the Spiš-Gemer Ore Mts. was monitored by discharge measurements and laboratory analyses of mine water chemical composition. Regression analysis of these data showed a statistically significant dependence of concentration of many important chemical elements on mine water discharge. The obtained data made it possible to better understand the processes of mine water chemical composition genesis, as well as to determine in more detail the degree of its environmental impact. Geochemical calculations and forward geochemical modelling suggest that chemical composition of mine water is formed in three stages. First phase takes place in the aeration zone of the mine, where ankerite dissolution, intensified by pyrite oxidation, dominates. In saturated zone of the mine, ankerite dissolution is probably controlled by CO2 input in open carbonate system. These two main geochemical processes take place permanently and at the time of low flow conditions they lead to relatively stable composition of water outflowing from mine. In time of higher flow conditions, concentration of SO4, Mg, Ca, Na and As significantly increases, probably as a consequence of mixing with stagnant water from deeper or hydraulically more isolated parts of the flooded mine. Water flowing out from mine enters the Rudniansky potok creek and contaminates it mainly by manganese. The limit for Mn content in surface water is exceeded here at the time of low flow conditions – usually for 180 days a year. Anomalous concentrations of SO4, Mg, As and Sb in mine water are sufficiently diluted in stream water were they do not exceed environmental limits.

Study of the effect of matrix components of natural mineral water on the determination of dissolved forms of silicon by high-resolution electrothermal atomic absorption spectrometry with a continuous spectrum source

The influence of the mineral composition of water on the results of silicon determination by high-resolution atomic absorption spectrometry with a continuous spectrum source (HR-CS-ETAAS) and electrothermal atomization technique using a contrAA 700 spectrometer has been studied. The study was conducted using samples of natural water from different regions of the Russian Federation and model solutions. A low degree of silicon atomization was recorded when analyzing samples with a complex matrix against the background of a strong absorption signal of matrix components. The reason for the non-selective absorption of the sample matrix by chemical compounds has been demonstrated using a water sample with the most complex composition and a total hardness of about 2000 °dH. The effect of soluble salts of Ca (II) and Mg (II) in the presence of macrocomponents — alkali metal ions K (I) and Na(I) — on the determination of silicon in water has been proved. It is shown that at the values of the total stiffness less than 15 °dH there is no dependence of the analytical signal on the content of matrix components. An assumption is made about the strong influence of calcium compounds on the determination of the analyte due to the formation of a carbide coating on the surface of a graphite furnace, the appearance of a «memory effect» and an increase in the background signal during subsequent atomization cycles. The best results of the silicon determination were obtained with tungsten, iron, magnesium, and palladium present as chemical modifiers. A method of diluting the sample solution was used to reduce the level of background absorption during electrothermal atomization of mineral water. Conditions for eliminating the influence of matrix components for real samples of mineral water and calibration solutions are proposed. A method for determination of the dissolved forms of silicon in water samples with a complex matrix has been developed. The correctness of the results of silicon determination in the samples of natural underground water in the case of a strong matrix effect was confirmed by an independent method of analysis. The results of the study reveal the entirely new prospects of using the method of high-resolution electrothermal atomic absorption spectrometry with a continuous spectrum source for the determination of silicon in natural water.

Geophysical monitoring of the geodynamic regime of Central Armenia

Geophysical monitoring of the geodynamic regime of the territory of Armenia is carried out including observations of the chemical composition of groundwater, changes in the stress-strained state of the earth’s crust and current seismicity. Hydrogeochemical effects of changing the stress-strained state of the medium as indicators of modern geodynamic processes have been revealed. Based on published data, the authors suggest that the nature of the manifestation of geochemical anomalies depends on the parameters of the forthcoming seismic event – magnitude (M) and epicentral distance (Δ). A map of the spatial-temporal distribution of deformations of the earth’s crust because of earthquakes over the past three years in the region has been compiled. The main components of ionic (Cl–, HCO3, SO4, Mg2 +, total mineralization) and gas (CO2) composition of mineral waters in comparison with seismicity in the earth’s crust are studied. A map of the distribution of earthquake epicenters in space and in time has been compiled. The obtained graph shows the hypocenters dependence of magnitude of earthquakes that occurred during the investigated period on the depth of hypocenters. Earthquake catalogue is using to plot earthquake recurrence. Statistical analysis of observational data showed that the most informative predictive characteristic is the dispersion of carbon dioxide content in water. According to the time series of concentrations of chemical indicators, the effects associated with the geodynamic regime of the earth’s crust of Central Armenia were determined. A map of the distribution of deformations in the earth’s crust of central Armenia was compiling taking into account the depths of the hypocenters of earthquakes.

RETURNABLE BAKING WASTE — A NEW TYPE OF RAW MATERIALS FOR DISTILLATES PRODUCTION (PART IV. SPIRIT DRINK)

A distillate is a basis for the blend of a spirit drink. Distillate ripening is necessary to stabilize the physicochemical composition and achieve certain flavor characteristics. Softened water is the second ingredient of the spirit drink blend in terms of volume. The mineral composition of water influences the consumer properties of a drink. The aim of this work is to reveal factors that influence quality indicators of a spirit drink from a new type of a raw material. The objects of the research were the samples of the distillate from baking waste, commercial batches of softened water and experimental blends of a spirit drink. The authors determined the volume fraction of ethanol, organoleptic characteristics and mass concentration of the main volatile components by the gas chromatography method in the objects of the research. It was established that upon distillate ripening, the most intensive oxidative processes occured in a period of 10 to 20 days. This led to an increase in the acetaldehyde concentration by 6–27% depending of a raw material type. At the same time, an increase in the mass concentration of ethyl acetate by 15 to 30%, as well as the total concentration of ethyl caproate, ethyl caprate, ethyl caprylate by 27–38% was observed. An effect of the strength of the spirit drink on its organoleptic characteristics was revealed. The mineral composition of the soften water samples prepared by the method of ion exchange and reverse osmosis was studied. Based on the analysis of the taste and aroma profiles of spirit drinks, an effect of the concentration and ratio of mineral salts in water on product quality characteristics was shown. The authors recommend the optimal duration of distillate ripening before blending — not more than 20 days, the blend strength 40–42% vol. The necessity to use soften water prepared by the method of ion exchange or reverse osmosis with the controlled content of ions of calcium (not more than 9 mg/dm3), sodium (not more than 60 mg/dm3), sulfates (not more than 65 mg/dm3) and hydrogen carbonates (not more than 80 mg/dm3) for blending was substantiated.

Dissolution characteristics of gas in mine water and its application on gas pressure measurement of water-intrusion coal seam

In order to determine the gas pressure for water-intrusion borehole, this work proposed a new method for measuring gas pressure based on gas solubility. A series of laboratory experiments and field test were carried out to investigate the composition of mine water, the gas solubility in mine water and the gas dissolved amount in borehole water over time. Then, a new method and equipment were proposed to test the gas pressure for water-intrusion borehole in Taoyuan (TY) coal mine and Xinhu (XH) coal mine. Results showed that, the cations of mine water are dominated by K+ and Na+, and the anions are controlled by Cl− and HCO3–. In addition, there are a certain amount of soluble organic matter in mines water. Then, the gas solubility increases with the rising equilibrium pressure while decreases with the growing temperature and salinity. It is noticed that the solubility of gas in mine aqueous solution is significantly higher than that in distilled water, which is mainly affected by the solubilization of soluble organic matter. Furthermore, the influence mechanism of various factors on the gas solubility was revealed based on the gap filling theory, hydration theory and organic matter solubilization effect. Finally, a self-developed equipment was used to test the amount of gas dissolved in the water-intrusion borehole, and the coal seam gas pressure was calculated and verified. The research results provide a new idea, equipment and method for the measurement of gas pressure in water-intrusion coal seam.

Environmental problems in the coal mining industry in Russia

The coal mining industry of Russia is characterized. Today, this industry is one of the most polluting types of human activity. The article provides a comprehensive assessment of the coal industry current impact on the environment, namely on the atmospheric air, the lithosphere, natural reservoirs, etc. The authors have analyzed the reasons and consequences of this industry negative impact on nature and man. The main sources of technogenic load on the environment during the coal deposits development are identified. Such sources include rock dumps, mine water, main ventilation fans, degassing installations, etc. The influence of rock dumps on the natural environment is investigated. The negative impact of the discharge of insufficiently treated mine water on the state of not only natural reservoirs, but also all components of the environment is shown. The composition of mine waters has been studied, which is important when choosing the technology for their treatment. Measures and methods to improve the environmental situation in the places of coal deposits development are considered. In particular, it is proposed to purify mine waters for the purpose of their use for technological, household, agricultural and other needs. The harmful and dangerous factors of the methane presence in the coal deposits development are shown. It is proposed to capture methane for further use, which will reduce its entry into the atmospheric air and at the same time make an economic profit. The principles of ensuring environmental safety in the coal mining industry are considered. Methods of reducing the anthropogenic load using the latest technologies are proposed. The conducted research is relevant and important for the further development of the coal mining industry in the framework of conservation and protection of the natural environment.

До питання уніфікації шифрування стану водних басейнів при космічному зондуванні

До питання уніфікації шифрування стану водних басейнів при космічному зондуванні

Testing new peat-free substrate mixtures for the cultivation of perennial herbaceous species: A case study on Leucanthemum vulgare Lam

One of the major challenges for nursery growers is replacing peat with more sustainable materials that may also represent a worthy strategy to recycle organic refuse. Among organic matrices, coconut coir dust, green compost, and stabilized wood fibre are considered promising alternative to peat because of their suitable physical-chemical characteristics. These matrices were used to prepare substrate mixtures designed to achieve physical characteristics similar to those of the standard peat-based substrates usually adopted by growers (peat:pumice, 70:30 v v−1). An experiment was carried out in open field with Leucanthemum vulgare Lam., a plant species that could be used for ecological restoration, by using both the native and the ornamental variety of the same species (L. vulgare cv. ‘Filigran’), the latter as test plants. Six different growing media were tested: (i) peat:pumice 70:30 v v−1 (PP), used as commercial control; (ii) coconut coir dust:pumice, 70:30 v v−1 (CP); (iii) coconut coir dust:green compost 55:45 v v−1 (CGC); (iv) coconut coir dust:stabilized wood fibre 60:40 v v−1 (CW); v) green compost:stabilized wood fibre 30:70 v v−1 (GCW) and, (vi) coconut coir dust:green compost:stabilized wood fibre 40:30:30 v v−1 (CGCW). Plant biomass, biometric parameters, plant and matrix/substrate mineral content, and mineral composition of water drained out from pots were measured as main performance indicators of plants and growing media. All the tested peat-free substrates, with the exception of GCW, adequately supported plant growth and quality. Moreover, CP and CGCW improved some of the investigated biomass and biometric parameters compared with the control treatment. Substrates containing green compost were found to improve plant nutrition, because of the high availability of mineral elements in the raw material.

Минеральный состав бутилированной воды в Северо-Западном Федеральном Округе

Introduction. Urolithiasis is a widespread disease with high the frequency of recurrence. An important preventive measure is an increase in daily urine output. Patients with urolithiasis need to take into account the mineral the composition of the fluid consumed, since it can affect the formation of stones. It is especially important to pay attention to the composition of bottled water purchased in retail chains due to its significant differences. Purpose. Analyze the composition of bottled water sold in retail chains of the Northwestern federal district (NWFD). Conduct a comparative analysis of the compositions carbonated and still water, as well as compare the composition of domestic and European bottled still water. Materials and methods. An independent laboratory determined the mineral composition of 36 samples of bottled water purchased in 2 retail chains of the NWFD. Done сomparison of the compositions of 19 samples of still and 16 samples of carbonated water. Comparison of the compositions of domestic and European non-carbonated bottled water. Results. The data obtained by us on the mineral composition of the purchased water samples corresponded to the indicators declared by the manufacturers. Comparison of carbonated and still water showed no statistically significant differences in the content of calcium, sodium, magnesium, potassium, sulfates, hydrocarbons. Comparison of the mineral composition of domestic still and European still bottled water showed the presence of statistically significant differences in the content of calcium and hydrocarbonates, which were higher in the water of European manufacturers. Conclusions. The mineral composition of bottled water can vary significantly. It is important for patients with urolithiasis to take into account the mineral composition of the water, which they consume, so it can influence the development of relapse.

NEW DATA ON HYDROGEOCHEMISTRY OF THE MINERAL WATERS OF THE CRIMEAN PENINSULA

Relevant data on the composition of mineral waters from 23 deposits and occurrences in the Crimean Peninsula are presented. The characteristic of 7 occurrences that have been previously unknown is presented. The studied waters are distinguished by broad-range variations in chemical composition, geochemical parameters of the medium, and the concentrations of biologically active components. Waters with the composition SO4-Cl-HCO3 Na, Cl Na, SO4-HCO3 Mg-Ca-Na, SO4-Cl Mg-Nam with TDS from ultra-fresh to brine level (0.4 - 202.9 g/dm3) are dominating. The waters relate to two large groups according to the geochemical parameters of the medium. The first group is characterized by reductive conditions with Eh from -330.2 to -22.3, pH from 7.3 to 9.1 and O2dissolved concentration 0.79 - 6.48 mg/dm3. The second group is characterized by oxidative Eh (+22.1 - +158.5), neutral and weakly alkaline pH (7,0 - 8,4), and O2dissolved concentrations from 2.73 to 6.92 mg/dm3. The studied waters exhibit a broad range of balneological properties, which allowed us to distinguish 13 types of mineral waters.

Origin and evolution of chemical composition of mineral waters of Szczawno-Zdr\xf3j inferred from long-term variation of ionic ratios, Sudetes Mts. (SW Poland)

The archival records of chemical composition of mineral waters in Szczawno-Zdrój spa were analyzed in terms of variation of ionic ratios to explain the possible source and origin of the major compounds dissolved in water and evolution of groundwater chemical composition in time. The analyzed data contained the longest available series of chemical records, dating back to 1962, and related to waters discharged by five main springs: Dąbrówka, Marta, Młynarz, Mieszko and Mieszko 14. The research showed that mineral waters in Szczawno-Zdrój belong to shallow meteoric CO2-rich, Rn-containing groundwaters which form their chemical composition mainly through the interaction with aquifer rocks. Detailed analysis of long-term variation of ionic ratios revealed that (1) the carbonates weathering, mostly acid hydrolysis of limestones and dolomites, and (2) the ion exchange reactions with clay minerals, mainly the so-called natural softening, play a fundamental role in formation of the chemical composition of studied waters. Both processes are responsible for the occurrence of dominant ions in solution such as Ca2+, Mg2+, Na+, and HCO3−. The aluminosilicates hydrolysis occurs with variable extent, but plays rather secondary role in formation of chemical composition. The time distributions of major element concentrations in studied waters showed a characteristic “concave” shape, indicating the decrease in concentrations beginning in the 60s and ending around 2005–2010. Such “concave” shape trends are not reflected in time distribution of ionic ratios which strongly suggests the occurrence of a simple dilution of chemical composition of mineral waters by the influx of fresh water. The observed considerable fluctuations of chemical composition of mineral waters in Szczawno-Zdrój are most probably associated with climatic factors, namely: the increased amounts of atmospheric precipitation in particular periods of time and its seasonal distribution. Such influx of fresh waters reduces considerably mineralization of shallow groundwaters and directly increases springs discharge.