Zone Of Active Water Exchange Research Articles

Подземные воды среднеюрских отложений южных районов Республики Коми

The features of the chemical composition of fresh groundwater of the Middle Jurassic aquifer complex in the southern regions of the Komi Republic, which is the main source of drinking water supply, are shown. Groundwater is mainly confined to the sole, composed of quartz sands, of the Sysol formation of the Middle Jurassic (J2ss) and is distributed at depths from 13.7 to 119 m. The waters are confined to the zone of active water exchange, to the areas of infiltration of atmospheric precipitation in the territory with a humid climate. The waters have a bicarbonate-calcium composition, a near-neutral medium, mineralization up to 0.58 g/dm3 and after preliminary water treatment (degreasing, demanganation) can be used for drinking purposes. Based on the conducted geochemical studies and statistical data processing, the main patterns of the distribution of macro- and micro–components in the groundwater of the Middle Jurassic sediments have been established, the leading processes of formation of the main components of the chemical composition of groundwater — oxidation, hydrolysis, cation exchange and sulfate reduction — have been identified.

Distribution of stable Н, О and С isotopes in natural waters in the area of the Taz oil and gas condensate field (Yamalo-Nenets autonomous region)

Relevance. The study of isotopic composition of water and dissolved substances makes it possible to determine not only their genesis, but also the fractionation processes occurring in the “water–rock–gas–organic matter” system over time, i. e. as different stages of the evolution of water composition pass through. Interest in the groundwater of the Arctic regions of Western Siberia is additionally associated with the widespread occurrence of oil deposits at the depths of formation waters and the possible influence of cryogenic metamorphization processes on composition of near-surface waters. Aim. To study and compare the isotopic composition of oxygen, hydrogen and carbon in natural waters of the Yamalo-Nenets autonomous region to identify conditional isotopic markers, as well as to be able to trace the evolution of the isotopic composition of waters along a vertical section in the area of the Taz oil and gas condensate field. Objects. Surface (river, soil and lake), underground waters of the active water exchange zone of the Yamalo-Nenets autonomous region and formation waters of oil and gas deposits of the Taz field. Methods. The study of the isotopic composition of oxygen, hydrogen, and carbon of water-dissolved carbon dioxide was carried out in the Research Equipment Sharing Center at the Institute of Geology and Mineralogy SB RAS using Isotope Ratio Mass Spectrometer FinniganTM MAT 253 equipped with H/Device and GasBench II for sample preparation. Results and conclusions. The paper introduces the data on isotopic composition of O, H and C for natural waters of the Yamalo-Nenets autonomous region. The authors have determined the characteristic trends in changes in the isotopic composition of water and dissolved carbon dioxide for various water bodies. Surface and underground waters with active water exchange in terms of isotopic composition (δD and δ18О) are infiltration. As water moves down the section, with an increase in the time of interaction of the “water–rock” system and increase in temperatures, the isotopic composition becomes significantly heavier with a slope from the GMWL to the right. The authors compiled the diagram of the evolution of water-dissolved carbon isotopic composition in the region according to the obtained and some literature data. Despite the wide range of δ13C values from –30.4 to 23.6 ‰, there are, obviously, only two sources of carbon dioxide in the region: biogenic and atmospheric, with biogenic being predominant for groundwater.

ОСОБЛИВОСТІ ХІМІЧНОГО СКЛАДУ ПІДЗЕМНИХ ВОД У ТЕРИГЕННИХ ВІДКЛАДАХ ЕОЦЕНУ ТА АЛЬБ-СЕНОМАНУ В БАСЕЙНІ ДНІПРА

Background. The Dniprovsko-Donetskyi Artesian Basin is the largest hydrogeological region of the first order in Ukraine in both area and resources. The main forecasted resources within its boundaries are confined to the Eocene aquifer and the Alb-Cenomanian aquifer complex. These aquifer and complex are the principal ones - they are the basis for centralized water supply of a number of large settlements, so studying their chemical composition is of exceptional importance. The parts of the mentioned aquifer and complex that contain drinking water are identified as groundwater bodies (GWBs) – groundwater monitoring objects for which environmental objectives and risks of failure to achieve these objectives should be determined. At the same time, the natural water quality composition of these groundwater bodies groups is characterized by significant spatial heterogeneity, which should be taken into account when determining trends in its changes and specifying environmental objectives. The aim of the study was to establish the peculiarities of the spatial distribution of water with different chemical composition. The object of the study was aquifers in Eocene and Alb-Cenomanian sediments within the Dniprovsko-Donetsky artesian basin (Dnipro River Basin), and the subject was the chemical composition of water in these aquifers. Methods. To achieve these purposes, data on the chemical composition of the aquifer in the Eocene sediments and the aquifer complex in the Alb-Cenomanian sediments were collected, summarized and analyzed from published and fund sources. The information was processed using geographic information systems, and a database was created to generate specialized maps and perform joint data analysis. Results. In the article the mineralization and macrocomponent composition of groundwater in the terrigenous sediments of the Eocene and Albian-Cenomanian of the Dnipro basin are investigated and the peculiarities of their spatial distribution are established. Particular attention is paid to the areas where the exploitation reserves of both groundwater aquifers are explored. The qualitative, including microcomponent, composition of groundwater in terrigenous sediments of the Eocene and Albian-Cenomanian in Chernigiv City was characterized in detail. Peculiarities of formation of the chemical composition of groundwater in terrigenous sediments of the Eocene and Albian-Cenomanian were established. Сonclusions. It has been established that despite the fact that both GWBs are located in the zone of active water exchange, the content of macro- and microcomponents in them is quite different. In particular, in the water in the Alb-Cenomanian sediments, the macrocomponent composition of water is more homogeneous, and the content of macro- and microcomponents is characterized by a smaller range of variation. The identified peculiarities of the natural quality composition of the studied GWBs should be taken into account in the process of groundwater monitoring, in particular, when specifying environmental objectives and determining the frequency of groundwater quality state observations.

The occurrence and distribution of rare earth elements in mineral and thermal waters in the Polish Lowlands

The occurrence and distribution of rare earth elements (REEs) in mineral and thermal waters encountered in Quaternary, Mesozoic and Permian aquifers of the Polish Lowlands are described, with REE concentrations analyzed in 35 groundwater samples and 25 aquifer host rock samples. The waters analyzed are characterized by high variability of total dissolved solids (TDS: 0.44 to 340 g/L) and of outflow temperatures (9 to 89 °C). Values of ultralow concentrations (pg/L-μg/L) of REEs in groundwaters of variable salinity were obtained using a novel method combining a seaFAST-pico preconcentration system with inductively coupled plasma mass spectrometry (ICP-MS). Very low concentrations of dissolved (<0.45 μm) REEs and Y are present in these waters, ranging from 0.6 ng/L to 19.1 μg/L and from 1.7 to 54.5 ng/L, respectively.The REE-patterns, normalized to European Shale (EUS), were used to assess the range of REE fractionation between water and host rocks and to show differences in REE distribution in various hydrogeological systems.Three groups of REE-patterns were distinguished: (i) upwards-sloping with HREE-enrichment (74% of all samples), (ii) convex with MREE-enrichment (20%), and (iii) near-flat with very slight depletion in HREE (6%). REE fractionation in shallow waters was attributed to the adsorption of LREE on Fe/Mn oxide/oxyhydroxide particles and the simultaneous complexation of REEs with carbonate and bicarbonate ions. In waters occurring below the zone of active water exchange, in reducing conditions, HREE-enriched patterns developed, mainly as a result of reductive dissolution of previously adsorbed and/or precipitated REEs. The convex, MREE-enriched patterns resulted from a combination of several geochemical processes controlling REE fractionation: (i) high temperature (T > 60 °C) favouring a release of the more easily soluble MREEs from rocks into the water, (ii) the presence of organic material showing a strong ability to form complexes with REEs, (iii) reductive release (dissolution) of previously adsorbed REEs on mineral particles, and (iv) dissolution of rocks by acidic waters.Our findings confirmed that REEs can be a useful markers for identifying basic hydrogeochemical processes shaping the chemistry of waters.

Еколого-геохімічна характеристика природних вод у межах впливу Добрівлянського газоконденсатного родовища (Передкарпаття)

A study of natural waters within the influence of the Dobrivlyany gas condensate field, located in the Dobryany and Dobrivlyany area village councils of the Stryi district of the Lviv Region of Ukraine, was conducted. The purpose of the work is to evaluate the geochemical indicators of natural waters based on our own research, to find out the role of natural and man-made factors in the formation of the chemical composition of waters. The objects of the research are surface waters and groundwaters within the influence of the Dobrivlyany gas condensate field. Research results. In the research area, as well as in the Bilche-Volytsia zone in general, there are unfavorable conditions for active water exchange and the formation of fresh infiltration waters, since the upper part of the geological section is characterized by clayey Neogene deposits. The depth of penetration of fresh hydrocarbonate-calcium waters here does not exceed 70 m. The small thickness of the zone of active water exchange is one of the indicators of difficult water exchange in the subsoil, therefore, favourable conditions for the preservation of hydrocarbon deposits. As a result of exploratory work, the Dobrivlyany gas condensate field was opened in 2016. During 2016–2019, 7 boreholes were drilled, and industrial gas inflows were received from horizons LD-9, LD-12, and N1kr+K2. In tectonic terms, the deposit is confined to the northwestern part of the Kosiv-Ugersko subzone of the Bilche-Volytsia zone of the Carpathian Foredeep. Observation of the macro component composition of groundwater from the wells of the Dobrivlyany gas condensate field indicates the stability of the hydrodynamic conditions of the deposit and, accordingly, the low variability of their geochemical characteristics. Direct hydrogeochemical zonation is clearly manifested in the increase in water mineralization with depth: for the LD-9 horizon at depths of 800–840 m, it varies within the range of 34.74–48.55 g/dm3, for LD-12 at depths of 995–1010 m – 33.82–73.70 g/dm3 and for N1kr+K2 at 1131–1158 m – 67.49–100.31 g/dm3. The content of Br and J doubles with depth. All waters are of the chloride-calcium type (according to Sulin), and genetic indicators vary within narrow limits (rNa/rCl – 0.82–0.91; Cl/Br – 216–315; rSO4 ∙ 100/rCl – 0.003–0.5) and indicate their thalassogenic sedimentogenic origin. The analysis of research results showed that underground waters belong to a single hydrodynamic system, and are characterized by the same type of water according to their chemical composition. According to the qualitative characteristics of groundwater from an ecological borehole and a well in the Dobrivlyany village remain clean and meets regulatory requirements for drinking water. At the same time, water from a well in Vivnya village is characterized by a high content of nitrates (2.28 maximum permissible concentration), which is caused by the location of the pig complex “Halychyna-Zakhid” LLC on the outskirts. Increased content of organic substances in the waters of two wells of the Railiv village was also established, in which the permanganate oxidizability reaches 1.08–1.24 maximum permissible concentration, and, according to Hygienic requirements for drinking water intended for human consumption, is unfit for consumption. The waters of the Kolodnytsia River are chloride-hydrocarbonate sodium-calcium (calcium-sodium) in composition, while the waters of the Stryi River and the Zhizhava River are calcium bicarbonate.

МІНЕРАЛЬНИЙ СКЛАД, ГЕОХІМІЧНІ ОСОБЛИВОСТІ І ВПЛИВ НА ДОВКІЛЛЯ ВІДВАЛУ ФОСФОГІПСУ НОВОРОЗДІЛЬСЬКОГО ЗАВОДУ СКЛАДНИХ МІНЕРАЛЬНИХ ДОБРИВ (ЛЬВІВСЬКА ОБЛ.)

Phosphogypsum of Novorozdilsky Plant of Complex Mineral Fertilizers (Lviv region) is a typical artificial neogenic mineral formation, solid waste by-product generated when sulphuric acid reacts with the phosphorus-containing ores (apatite or phosphorite concentrates) during manufacturing of phosphoric acid. The raw materials for fertilizer production at the plant were sulphuric acid, which was obtained from the sulphur ores of Rozdilske SMCE “Sirka”, apatite concentrate from the Khibiny deposit (Kola Peninsula) and, to a lesser extent, phosphorite concentrate from sedimentary phosphorites. The plant has not been operating since 1995, but 4.5 million tons of phosphogypsum and also acidic mineralized water in the settling lake have accumulated on its territory since then. Gypsum (85–95 %) and bassanite (5–10 %) dominate in the mineral composition of phosphogypsum, there are also undissolved apatite (up to 2–3 %) and trace amounts of minerals that were originally in apatite concentrate (quartz, nepheline, pyroxene, aegirine, feldspar, biotite, etc.). The surface of the phosphogypsum heap is a phytophilous man-made substrate that is actively overgrown with woody vegetation. This is due to the filtration properties of phosphogypsum Василь Дяків, Ельвіра Джумеля, Мирослав Ковальчук та ін. 106 ISSN 2078-6220. Мінералогічний збірник. 2022. № 72 (they promote water accumulation and leaching of phytotoxic compounds from the zone of active water exchange) and the presence of a significant amount of phosphates. Currently, a dense aspen-sea buckthorn forest grows on the slopes of the dump. Acidic infiltrates are formed in the process of infiltration of precipitation through the thickness of the phosphogypsum dump, they are accumulated in the settling lake (Central/Acid Lake). In terms of chemical composition, it is sulphate-phosphate sodium-magnesium-calcium water with high fluorine content and mineralization of 2931.6 mg/dm3. The cessation of the use of the lake (as a settling tank for the plant's circulating waters) and the constant accumulation of infiltrate have led to a number of environmental problems. Acidic infiltrates flow into the mine canal and significantly impair the quality of water in it. Only due to the dilution of infiltrates with clean water of the drainage channel (with a flow rate of three to four times higher) before flowing into the transboundary Dniester River hydrochemical composition of water meets the normative values of salt composition and content of major pollutants. Deterioration of the water quality of the mine canal and, as a consequence, pollution of the Dniester in case of prolonged drought or reduction of the debit of the drainage canal are envisaged. To minimize the negative impact of the phosphogypsum dump on the environment, a project to build a cascade of filter dams from local carbonate materials has been proposed. Limestones have the ability to neutralize acidic waters; they are highly permeable and contain sulphur, which causes the binding of heavy metals to insoluble compounds. Due to the interaction of carbonates with acidic infiltrates, water-insoluble calcium phosphates and calcium fluoride (fluorite) are formed, which helps to purify water from F and P, and newly formed hydrates reduce the moisture content of the phosphogypsum mixture with flotation tails. The proposed approach will make it possible to control a constant source of pollution and restore the ecological balance disturbed by economic activities

GEOTHERMAL FIELD OF BELARUSIAN PART OF PODLASKA-BREST DEPRESSION

The article presents an information on geothermal conditions of the platform cover within the Podlaska-Brest Depression, parameters characterizing the thermal field of the region. Geothermal maps of temperature and heat flow distribution were compiled based of thermograms registered in boreholes. Geothermal anomalies of temperature and heat flow distribution within the region and its adjacent geological structures are identified. They largely depend on the features of the geological structure of the crustal blocks. The variability of the thermal field within the territory of the zone of active water exchange (the fresh water zone) is considered. It is shown that the geothermal field of the region is characterized by its nonuniformity. Anomalies of low values of temperature and heat flow were identified in the adjacent parts of the Belarussian Anteclise and Polesie Saddle. Both the temperature and heat flow significantly increase in the Belarusian part of the Podlaska-Brest Depression. The maximum values of geothermal parameters were noted in parts of the depression adjacent to the Belarusian-Polish border. A decrease of the heat flow is observed in the direction of the Lukóv-Ratno Horst. An estimate of the density of geothermal resources for the strata of Cambrian deposits has been carried out. The density of recoverable resources in this stratum of the region varies in a wide range: from 0 (at the eastern boundary of the depression, when they pinch out) to more than 350 kg o. e/m2. The maximum values are observed northwest of Brest in the area adjacent to the Belarus-Poland border, in particular, within the well-studied geothermal Pribug Structure. They represent the interest for practical use.

Low Heat Flow at Shallow Depth Intervals: Case Studies from Belarus

The territory of Belarus belongs to the western part of the Precambrian East European Platform. Its heat flow pattern is representing by alternating low and high heat flow anomalies. An overwhelming majority of heat flow determinations and in general of geothermal observations in Belarus were fulfilled in boreholes finished in the platform cover. Within the Belarusian Anteclise, Orsha Depression, western slope of the Voronezh Anteclise their bottom holes are typically within the zone of active water exchange, where the groundwater circulation sufficiently influences on recorded thermograms. For instance, observed heat flow density for a number of studied boreholes is low and ranges on average from 15–20 until 35–40 mW/m2 within the Orsha Depression. In a number of studied holes in the northern part of the structure, its values are surprisingly low. They are observed within upper horizons of the zone of active water exchange with pronounced groundwater circulation. Permeable rocks within the geologic section comprise the platform cover with a number of freshwater intervals. Their base is spread here up to depths of 150–250 m. The most of heat flow observations within this area were studied in boreholes which depths is only 200–300 m, sometimes less, as deeper wells are seldom within this geologic structure. Groundwater circulation within loose sediments cools them, most of thermograms here have a concaved shape to the depth axis. As a rule, heat flow values are sufficiently lower in a number of intervals in boreholes finished in the freshwater zone, relatively to the heat flow observed within deeper horizons of the platform cover. In some of studied boreholes, the observed heat flow is as low as 5–15 mW/m2. In most cases it has a tendency to stabilise only at intervals deeper than 600–800 m. It is the main reason for observed low heat flow zones.

Evaluation of the effectiveness of drainage systems within the Desantne Village Council in Kiliya district of Odessa region

Relevance of research. Irrigated agriculture in the steppe regions of the southern Ukraine was naturally accompanied by negative phenomena. Among the most significant of them is flooding on agricultural land as a result water imbalance of the active water exchange zone when using irrigation. A significant part of this water as filtration losses from the irrigation network and directly when watering land goes to the aeration zone and reaches the surface of groundwater, increasing its supply. As a result, the groundwater level increases, the amplitude of which increases depending on the depth of groundwater, the intensity of irrigation, the distance from the irrigation network, the method of irrigation and other factors. In recent years, the number of actually irrigated areas located on irrigated lands is significantly reduced and at the same time the area of "dry" drainage is increasing. Therefore, one of the most pressing problems for today is the analysis of the condition of drainage and discharge network throughout Ukraine. Thus, the purpose of the research is to study the drainage and discharge network of the south-west of Odesa region to determine the current condition and prospects for its further use. The objectives of the research include monitoring of groundwater levels for the period of 1991 - 2019, determining the condition of the drainage and discharge network within the Desantne village council in Kiliya district of Odessa region. Theoretical methods of scientific research were used: monitoring, observation, analysis, survey, evaluation, comparison, generalization. The results of the study of closed drainage systems in the Desantne village council in Kiliya district of Odessa region showed that their effectiveness is insufficient. Recently, due to the cessation of irrigation at the research and production sites, groundwater level has fallen below the drains, the drainage has stopped operating and has been in a dry condition for a long time. The groundwater level in the drainage areas was at the depths of mainly 3.5-4.3 m. 24% of the inspection wells were destroyed, and 38.6% of them had no reinforced concrete cover rings. For a long time the closed horizontal drainage has been in unsatisfactory technical condition.&#x0D; Main conclusions: Drainage on irrigated lands should optimize the water-salt regime of soils, while moisture and salt reserves during the growing season in the root zone should be strictly dosed and ensure high crop yields as well as suitable hydrogeological and reclamation conditions on irrigated lands and adjacent areas. Introduction of large-scale parcellation of land and the land of reclamation funds as well as paid water use should not lead to the deterioration of the technical condition of the collector-drainage network.&#x0D; Drainage systems, as a means of groundwater level reducing, are especially relevant in land reclamation and flood protection of rural settlements. In the southern regions of Ukraine this problem was dealt with by Bayer R., Zelenin I., Lyutaev B., Miedviediev O., Miedviedieva O., Romashchenko M., Savchuk D. and others. Most systems were built on irrigation arrays in the Soviet times, ie 30-50 or more years ago. Redistribution and parcellation of agricultural land have led to the decline of the systems and the deterioration of their efficiency. Such works allow to analyze the operation of each drainage systems and make reasonable conclusions about their further use in terms of economic and environmental feasibility.

Assessing the ground waters of Bulgaria using a Water Quality Index

The study focuses on the quality of shallow groundwater in Bulgaria based on the content of major ions. To be safe for drinking purposes, their concentrations must not exceed the respective thresholds. The groundwater quality is assessed in terms of health hazard by a groundwater quality index (GWQI or WQI), and the respective map is presented. The results show that for the territory of Bulgaria, this index varies from 13 to 92. The highest values of this index (related to health hazard) are typical for the lower hypsometric zone of the country. The shallow groundwater in the zone of active water exchange is distributed as follows: waters of excellent quality, waters of good quality, waters of poor quality, and waters of very poor quality, covering 3%, 39%, 22%, and 31% of the whole area of the country, respectively. In this study, no estimates have been made for 5% of the territory of Bulgaria, which is characterized by the presence of very hard groundwater.

The application of selected hydrochemical indicators in the interpretation of hydrogeochemical data – A case study from Busko-Zdrój and Solec-Zdrój (Poland)

Abstract The processes affecting the formation of the chemical composition of the waters take place in specific hydrochemical zones. The knowledge of such phenomena allows to draw conclusions regarding the origin and conditions prevailing in the regions of their occurrence, e.g. indicate a zone of active water exchange, i.e. an inflow of infiltration waters, or a zone of isolated geological structures, where diagenesis processes take place. The aim of the study was to assess the hydrochemical conditions which affect the formation of chemical composition and genesis of origin of sulfide waters from the Busko-Zdroj and Solec-Zdroj region (Poland) using selected hydrochemical indices (rNa+/rCl−, rNa+/rK+, rNa+/(rNa++rCl−), rSO42− × 100/rCl−, rCl−/rBr−, rHCO3−/rCl− and the weight index: Cl−/Br−). A detailed analysis was carried out for sulfide waters from fifteen intakes and five springs. Several aquifer systems are found in the study area. Investigated intakes and springs differ in terms of stratigraphy and lithology. The analysis of changes in the values of selected hydrochemical indices confirms that waters of the Busko-Zdroj and Solec-Zdroj region belong to two systems of circulation — “shallow” and “deep”. The formation of the chemical composition of analysed waters occurs mainly in the aquifer. The values of rNa+/rCl−, rCl−/rBr−, rNa+/(rNa++rCl−), and Cl−/Br− indices suggest that the salinity of sulfide waters may result from leaching of salt interburdens and inclusions. In the area of occurrence of sulfide springs, tectonic cracking zones enable the inflow of highly mineralized waters and thus contribute to the mixing of waters of different aquifers. High content of Cl− and Na+ ions as well as mineralization higher than in sea waters indicate the formation of waters from the upper Cretaceous level together with deposits in a sedimentary basin.

Rare-earth elements in groundwater of the abandoned Levikha copper mine (Middle Urals, Russia)

The distribution of REE in groundwater of the catchments, which were formed during the long-term operation of copper mines in the Middle Urals (Russia), was studied. The groundwater composition reflects a significant removal of REE from water-bearing rocks, which leads to their enrichment by several orders of magnitude relative to the oceans, surface water and groundwater. Maximum REE values (up to 15 mg/L) were recorded in groundwater discharged to the surface in the collapse zone (pH=3.5). In mine shafts REE values do not exceed 0.3 mg/L. Water of mine wastes occupy an intermediate position: here REE content varies from 0.5 to 6.5 mg/L. The degree of REE fractionation in mine waters is lower than in oceanic, surface and underground waters of the active water exchange zone at much higher contents. The chemical composition of groundwater of the abandoned copper mine is determined by hypogene processes and structure of the mineralized supergene zone, its mineralogical composition, and oxidation-reduction conditions.

Особенности микрокомпонентного состава природных вод на территории г. Перми

The micro-component composition of natural waters in the Perm urban-industrial agglomeration is poorly studied. The authors conducted studies of surface, underground, rain and snow waters in different phases of the hydrological cycle. As a result, it was found that rain and snow waters on the left bank of the Kama River are characterized by the highest pollution, and contain more elements than the background and elements emitted by road transport (V, Zn, Cu, Ni, Cr). In all watercourses of the city, the content of V, Cu, Hg, Sr is higher than the Maximum Contamination Level (MCL). In underground waters of the active water exchange zone, all the observed micro components do not exceed the MCL values.

Урожайність насіння томата сорту легінь залежно від схеми посіву та удобрення в Південному Степу України

Урожайність насіння томата сорту легінь залежно від схеми посіву та удобрення в Південному Степу України

Chemical composition of different types of natural waters in Ukraine

The results of studies of the chemical composition in various types of natural waters of the territory of Ukraine – atmospheric precipitation, surface (river and lake), groundwaters and sea waters are comprehensively summarized and presented for the territory of Ukraine in this paper. The chemical composition of Ukraine's natural waters (rivers, lakes, underground aquifers, seas) is the result of the interaction of a combination of natural factors, as well as their location, mainly in the temperate climatic zone. The average long–term mineralization of atmospheric precipitation is usually in the range of 20–40 mg/l, its chemical composition is predominantly sulfate magnesium–calcium. For the chemical composition of water in the small and medium rivers of Ukraine, hydrochemical zoning is observed in the direction from the northwest to the south-east of the country. Mineralization of river waters also increases in this direction (from 200–300 mg/l to 1,500–3,000 mg/l and more). The composition of the water varies from bicarbonate calcium in the north and west to sodium chloridein the south and southeast. The value of mineralization of lake water varies within very wide limits. There are lakes with very fresh water and low salinity (30 mg/l – small lakes of glacial origin in the Ukrainian Carpathians), and lakes whose water has a mineralization of more than 100 g/l (salt lakes of the Crimea). In the chemical composition of groundwater, the territory of Ukraine mainly exhibits vertical hydrochemical zoning, which manifests itself in the separation of zones of intensive or difficult water exchange. Hydrocarbonate or sulfate waters with a small mineralization (up to 1.0 g/l) are characteristic for the zone of active water exchange. Highly mineralized (50–300 g/l and more) chloride, sodium and chloride-sodiumcalcium waters are common in a zone of hindered water exchange. The ionic composition of the Black Sea water has all the characteristic features of ocean waters but differs from them in relative poverty with ions of chlorine and sodium, the average salinity of the Black Sea waters is 18–19 ‰. In the narrow coastal zone near the mouths of large rivers (the Danube, the Dniester, the Southern Bug, the Dnieper) a decrease in the salinity of the Black Sea waters (up to 5–10 ‰) is observed. The main factors that determine the salinity regime in the Azov Sea (10–13 ‰) are the inflow of saline Black Sea and fresh river (the Don and the Kuban rivers) waters that are mixed in the Azov Sea, as well as the arrival of atmospheric precipitation.

Characteristics of formation of chemical composition of groundwater of active water exchange zone of the Bodrak catchment area (South-Western Crimea)

The article focuses on study of the chemical composition of the groundwater zone of active water exchange. The site of research was the Bodrak catchment area (South-Western Crimea). Formation of groundwater is caused by the infiltration of precipitation. Its chemical composition is influenced by natural and anthropogenic factors, but primarily it is determined by the enclosing sediments. At the same time, a leading role belongs to the sand-and-clay and volcanic-sedimentary rocks of Triassic and Jurassic. The predominant ions in the chemical composition of groundwater are mostly HCO3–, Ca2+. Factors affecting variations of chemical composition of groundwater of active water exchange in the Bodrak catchment area are revealed. First of all, this is the chemical composition of the enclosing sediments, under the influence of which the differences in the composition of the groundwater of sandy-argillaceous, volcanogenic-sedimentary horizons (T2—J1) and carbonate deposits (Cretaceous Paleogene) are formed. The nitrate ion and the association of Zn—Fe—Cu—Pb—Ni—Al in the groundwater zone of active water exchange are associated with anthropogenic impact. The series of elements Sb—As—Se—Co—Mo—Sn—Ag can be connected with the numerous sulfide nodules characteristic of rocks of flysch deposits (T2—J1) and carbonate deposits (Cretaceous—Paleogene).

О водохозяйственных проблемах на примере Оренбуржья

Interconnection of water/economic problems with a region forest content and necessity of forest/melioration measures and actions on water protection against pollution and depletion on the basis of the advanced techniques application has been shown. 337 water intake wells located mostly in the riverine zones where the main resources of fresh water situated have been tested. The investigation object was a zone of active water exchange of the regional hydrosphere with macro- and mezzo-basins of water runoff. It has been stated that the increasing scales of the technogenic processes cause negative geo/dynamic phenomena, growing natural disasters and hazardous risks. Measures on mitigation and prevention of the negative geo/dynamic processes have been vindicated and developed. Some methods of assessment of groundwater formation processes, as well as laboratory, calculation/graphic and experimental methods have been applied. Geological/geophysical and hydro/geological information with the results of physical/chemical analysis of natural and waste water samples (&gt; 2000 samples) have been summarized. Some cases of technogenic disturbance of the balance-unbalance water-rock-gas-living being system have been investigated. It has been concluded that it is necessary to stop deforestation, plowing up, dam construction and any other construction but water/protective one in river floodplains to preserve water resources. It is recommended to apply barrier techniques to protect water resources against pollution and to purify water.

Pleistocene age paleo-groundwater inferred from water-stable isotope values in the central part of the Baltic Artesian Basin

ABSTRACTA new data set of δ2H and δ18O in the groundwater from the central part of the Baltic Artesian Basin is presented. The hydrogeological section is subdivided into stagnation, slow exchange and active exchange zones. Na–Ca–Cl brine found at the deepest part – the stagnation zone – is characterized by δ18O values above −5 ‰ and δ2H values approaching −40 ‰ with respect to Vienna Standard Mean Ocean Water. The slow exchange zone where waters of mostly intermediate salinity reside is characterized by δ18O values around −11.7 ‰ and δ2H values around −85.3 ‰. Mean δ18O and δ2H values of the fresh groundwater in the active water exchange zone are −11.1 and −79.9 ‰, respectively. Characteristically, the groundwater in the active and slow exchange zone is isotopically more depleted compared with the precipitation values observed, and the depletion increases with depth down to the level where strongly enriched brines are encountered.

Contemporary approaches to studying and mapping of active water exchange zone of ground water

The article deals with a zone of ground water active exchange. New principles of the zone study and mapping under the platform hydrogeological condition are discussed. The assessment and distribution techniques are suggested for the active water exchange zone under the condition of hydrogeological parameterization uncertainty. The efficiency and significance of the suggested techniques are proved using the example of ground water in the southwest of Black Sea artesian basin.

Trace elements and rare earth elements in ground ice in kimberlites and sedimentary rocks of Western Yakutia

The paper presents unique results of studying the composition of the ground ice (major components, trace elements, and rare earth elements — REEs) encountered at a depth of 200–250m in sedimentary and magmatic rocks in the Western Yakutia diamond-bearing regions. In addition to those established earlier, three new geochemical types of ground ice have been defined: (i) sulfate-hydrocarbonate, (ii) chloride-hydrocarbonate, and (iii) sulfate-chloride types with mixed cation composition. The ground ice geochemical features are caused by evolutionary processes of interaction in the water–rock system during permafrost formation. The enclosed rocks were the source for the addition of sulfate and chlorine ions, as well as trace elements, to the ground waters of the active water exchange zone that had existed before freezing. The distribution pattern of REEs in ground ice has a special form distinct from that of sedimentary rocks, kimberlites, and ocean waters, but similar to the REE pattern in local river waters. This REE pattern features the positive europium (Eu) anomaly and approximate equality of light and heavy REEs. The obtained results essentially expand the insight into ice-formation processes in sedimentary and magmatic rocks.