The article presents the results of study of ferruginous mineral waters. The waters under consideration are discharged on the territory of Western Transbaikalia and belong to the anoxic sulfide-free and acidic types. The peculiarities of the formation of gas, major and trace elements, and dissolved organic substance composition have been established using modern methods. It has been shown that the chemical composition of the waters is greatly influenced by acid–base conditions. Acidic ferruginous waters contain large amounts of heavy metals; organic matter is mainly represented by low molecular weight organic compounds. The only metals present in significant amounts in ferruginous waters are manganese and zinc. Dissolved organic matter is represented by diverse types of high-molecular weight compounds that are formed as a result of biotic processes.

Water quality in the Modonkul’ River, flowing in a territory with mining industry, is considered. The analyzed data characterize the period 2019–2021. The assessment of pollution or the parameterization of water quality were carried out using the universal combinatory index of water pollution. In the upper reaches of the Modonkyl’ River, the water chemistry is of hydrocarbonate calcium type. In the zone of mixing of river and mine waters, the water chemistry changes to sulfate, mostly, sodium-calcium-magnesium type. The general regularity in the behavior of microelements in the Modonkul’ R. water is an increase in their concentration at an increase in TDS. Downstream the river, the concentrations of heavy metals increase: Cu, Zn, Pb by 1.1–1.4 times; Mn, Co, As by 6.6–11 times; and Cd, by 8 times. In the upper reaches of the river, its water quality was classified as weakly polluted, 2nd class. Further downstream, the water is classified as dirty, 4th class with a decrease in the subclass from a to b.

Relevance. Negative impact of waste from mining enterprises on the ecological state of the surrounding areas. Aim. To determine the migration ability of toxic chemical elements from waste storage sites of the Ermakovskoe beryllium deposit in the air. Object. Ermakovskoe fluorite-bertrandite-phenacite deposit and the surrounding area. Methods. Inductively coupled plasma mass spectrometry, laser diffraction, inductively coupled plasma atomic emission spectrometry. Results and conclusions. The paper introduces the experimental studies of surface atmospheric pollution by mining waste from the Ermakovskoe fluorite-bertrandite-phenakite deposit are presented using an installation for collecting aerosols above the sand surface. It was established that toxic components formed during the decomposition of residual sulfide mineralization and products of the interaction of acidic waters with rocks move from the sand thickness to the surface along with water vapor. The moisture condensed over the sand contains high contents of aluminum, iron, manganese, zinc, and phosphorus. These elements form a halo of air pollution over mining waste and are then dispersed by air currents into the surrounding area. In winter, due to wind dispersion of aerosols, the snow cover becomes contaminated over a vast area. Among the toxic elements found were beryllium, lead, cadmium, and molybdenum, which belong to the second hazard class. The solid residue of the snow cover contains a fine fraction of dust, the size of which is less than 10 microns. The halo of snow contamination with toxic chemical elements and dust extends several kilometers away from the disturbed lands.

— Experimental studies of the surface atmosphere pollution with mining and processing wastes of tungsten–molybdenum ore were carried out using an equipment devised for collecting aerosols above the surface of sands. It has been established that toxic components formed during the decomposition of residual sulfide mineralization and products of interaction between acidic waters and rocks are transported with water vapor from the sands to the surface. The moisture condensed over the sands contains high concentrations of aluminum, fluorine, iron, silicon, manganese, zinc, and phosphorus. These elements form an atmospheric pollution halo over the technogenic sands and are further dispersed by air currents over neighboring areas. In winter, the snow cover is polluted over a vast territory due to wind dispersion of the aerosols. The halo of pollution extends over tens of square kilometers. A dependence was identified of qualitative and quantitative composition of the components polluting the snow cover on the storage time of the ore processing products. It is shown that some of the toxic elements pass into solution during snow melting from suspended solids, which are brought by wind from the territory where the soil cover is disturbed by mining.

Pollution of bottom sediments of Lake Gusinoe by heavy metals (cadmium, chromium, copper, zinc, and lead) is considered. The exchangeable, reducible, and oxidized species of the elements were distinguished in bottom sediments, which were sampled in the central part of the lake and near mouths of main rivers and water discharge sites from SDPP (State District Power Plant), sewage treatment plant of Gusinoozersk, and Kholboldzha coal mine. Analysis of obtained data showed that Ni, Cr, Mn, and Fe occur in bottom sediments in hardly accessible form and in absorbed form on the surface of iron, manganese, and aluminum hydroxides. The high content of biologically available Cu, Zn, and Pb forms in the Zagustai and Tsagan-gol rivers creates a serious threat for the ecological state of the lake. The fractionation of heavy metal forms in the area of eliminated source of pollution related to the water disposal from the Kholboldzha coal mine showed that the content of heavy metals strictly bound with sample matrix is higher than that of the exchangeable fraction of elements.

Lake Gusinoe is the second largest freshwater lake in Transbaikalia. Lakes serve as a source for drinking water, irrigation, and as a water source for the electricity, aquatic production, and tourism industry. Currently variations of content nutrients and organic matter differ in different areas of the lake. The content of total nitrogen, phosphorus, organic matter, and dissolved oxygen are distinguished more than 1.2–2.0 times. In accordance with the behavior of elements in the water, three groups of elements can be distinguished. The first group of elements, including Li, Ga, Ge, As, Rb, Sr, Mo, Cd, W, and U, were directly correlated with variations of major elements. The first group of elements showed decreasing concentrations with an increasing amount of total dissolved salt (TDS). The second group of elements, including Fe, Y, Nb, Th, and REE, were correlated oppositely with variations of TDS. The behavior of the third group of elements, including Mn, Zn, Ni, Cu, and Pb, decoupled with TDS. The value of the Eu anomaly was positively correlated with TDS. The water of Lake Gusinoe was extremely enriched by W, Mo, V, U, Li, Sr, and Ga; moderately by Ni, Cu, Ge, As, Rb, Cd, and Pb; and minimally by Al, Cr, Mn, Fe, Co, Zn, Y, Th, and REE.

The purpose of this study is to determine the main hydrochemical parameters of Lake Kotokel deep waters, to identify the role of groundwater feeding it, as well as to establish the features of spatial distribution of macro- and microelements in the lake. Field work was carried out during the ice and ice-free seasons. A special sampler was used to take water samples from the bottom of the lake. Water samples were filtered through the filters with a pore size of 0.45 μm at the sampling site. Plastic bottles were used for the water samples for analysis. Polypropylene containers (15 ml) pretreated with 0.1 N nitric acid were used for the water samples for trace elements. The analysis of the macrocomponent composition of water was carried out in a certified Laboratory of Hydrogeology and Geoecology of the Geological Institute of the Siberian Branch of the Russian Academy of Sciences (Ulan-Ude) according to the standard methods intended for fresh and saline waters. Cations (Ca2+, Mg2+, Na+, K+) were determined by atomic absorption, F-, SiO2 – by the colorimetric method, HCO3- , CO32- and Cl- – by the titrimetric method, SO42- – by the turbidimetric method. The analysis of the trace element content was carried out in the Laboratory of Aquatic Microbiology at the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences (Irkutsk) by the method of inductively coupled plasma on Agilent 7500ce quadrupole mass spectrometer. Conducted research made it possible to determine an inhomogeneous chemical composition of lake water associated with the discharge of fissure-vein waters along the faults that bound the depression from the southeast and northeast and intersect the lake water area from the island to the Istok river. The highest content of dissolved substances was recorded in the strait between Monastyrsky island and the western shore of the lake; the maximum values of hydrocarbonate ion and total mineralization were found here. The maximum content of sulfate ion was found in the southern and southeastern parts of the lake. The dispersion in microelement distribution reaches several mathematical orders. The most variable concentration is characteristic of iron, manganese, copper, zinc, lead, phosphorus, molybdenum, tungsten, strontium. Their high contents were found in the lake water within the location of faults of northeast strike. Therefore, the chemical composition of the water of Lake Kotokel is largely formed by fissure-vein waters. This water is discharged along the tectonic faults of the northeastern strike. The research revealed two centers of subaqueous discharge, which are characterized by the formation of two different associations of microelements in the lake water. The composition of microelements in fissure-vein waters is determined by their interaction degrees with rocks.

The article considers the conditions under which the water resources and chemistry are forming in the mineral Bormashovoe Lake, which lies on the Svyatoi Nos Peninsula on the eastern coast of Lake Baikal. The study was focused on water and free gas, which releases from bottom deposits and lakes in the Svyatoi Nos Peninsula. The results represent the analysis of water samples taken in ice-free and ice periods and studied to determine a wide range of chemical elements by up-to-date methods. The geological conditions existing in the region are considered. It is found that the rocks in the area near the lake are represented by eluvial deposits that have formed at intensive physical and, to a lesser extent, chemical weathering of granites. The recharge of the lake is shown to be mostly due to the discharge of fracture-vein and subsoil water, which form the specific geochemical pattern of lake water. In winter, the decomposition of organic residues of bottom sediments causes a change in the physicochemical conditions in lake water and increases its content of hydrocarbonate ion, calcium, magnesium, and rare-earth elements. Factor analysis was used to identify associations of elements which form under the effect of discharge of deep fracture-vein water, unconfined water enriched by decomposition products of rocks that had suffered the stage of frost weathering and lake water saturation by carbon dioxide in winter. Thermodynamic modeling showed that equilibrium exists in the lake with respect to calcite and dolomite, and the precipitation of carbonate minerals causes the accumulation of sodium and hydrocarbonate ion in water, making it soda water.

Selenge River is a transboundary river, which rises in the Khanghai Mountains in Mongolia and flows into Lake Baikal in the Republic of Buryatia (Russia). We studied the Selenga River basin (446 000 km2) located in western Siberia (Transbaikalia, Russia), and northern and central Mongolia between the Tuva-Mongol and Dzabkhan microcontinents in the west, the Siberia craton in the north and the Amurian superterrane in the south. Water resources are very limited in this basin because annual precipitation is only 250-400 mm. Moreover, 90% of annual precipitation occurs in summer, which causes frequent flooding in summer and severe shortage of water during the rest of the year. The transition from a planned economy to a market economy has resulted in inefficiently operated wastewater treatment systems which pollute the river, and reckless deforestation have increased non-point pollution sources on the lower Selenge River in Russia. In recent years, of industrial water consumption more than 50% of withdrawn water was used by the mining industry in Mongolia. The mining enterprises are located in watersheds of small tributaries, the second order of the Selenge River. In this work we present the current state of the Selenge River chemistry and estimate heavy metal pollution. From 2004, the requirement of federal law of Russia «On the protection of Lake Baikal» the new variant of regional norms MAC (Maximum Allowable Concentration) were elaborated. The concentration of the main polluting substances were compared with norms MAC. The dissolved concentrations of major, trace elements, REE (rare earth elements), and dissolved organic carbon (DOC) have been measured in Selenge River draining watersheds with various surface areas. Measured pH for all sampling sites were within the standard range for river water, which is between 6 and 9, meantime the highest measured pH 9.2 may be due to anthropogenic influences in the area. The total dissolved solids load (TDS) is 108-297 mg l-1. Along the river Ca/Na ratio varies 2.1-9.8 that can be explained by the heterogeneity of the crystalline rock and soil. Mongolian and Russian parts of Selenge River having different drainage areas and hydrological parameters were sampled over a 6-year period. Collected data show that the river present the same monthly seasonal variations, with higher concentrations in winter and lower concentrations during other seasons. In waters, DOC and insoluble element concentrations (e.g., Al, Fe, and Th) were strongly correlated, which show the key role of organic colloidal matter in the transport of some insoluble elements.

The article presents the results of an experimental study of the possibility of removing heavy metals from solutions filtered through the thickness of the tailings of the Dzhidinsky GOK. It was found that as a result of the hydrolysis reaction of these salts (mainly iron sulfate), an acidic environment is formed, metal hydroxides are formed and a sulfate ion accumulates in the solution, which increases the migration of heavy metals both inside the tailings pond and outside it. Limestone is proposed as a neutralizing reagent. Different ways of adding limestone to man-made sand are considered. The use of 0.5-1 mm limestone by adding it to man-made sand makes it possible to increase the pH of solutions to 5.3.under these conditions, the content of a number of elements in the solution was reduced.

The Dzhidinsky orefield is located in the Zakamensky district of Buryatia. It is characterized by a high concentration of mineralization in a small area. The ores of the Dzhidinsky economic deposits are complex. This ore field includes Pervomaiskoye Mo, Kholtosonskoe W, and Inkurskoe W deposits. The catchment basin of the river Modonkul is located in the Dzhidinsky orefield. Mineral resource industry waste is a real threat to the city Zakamensk. Currently, the waste of deposits is located at the floodplain terrace and the watershed of the river Modonkul. In this work, the impact of the drainage mine and tributary Inkur on the formation chemical composition of the river Modonkul is studied. The 80 samples of water and suspended matter were taken from a surface of 0–0.5 m on seven sites. Physical and chemical parameters were measured at the sampling sites, and chemical composition was analyzed in the laboratory. In the natural background of the river, the major cations are, in decreasing order, Ca2+ > Mg2+ > Na+ + K+, and major anions are, also in decreasing order, HCO3− > SO42− > Cl−. Along the river, the chemical type of water changes from bicarbonate to sulfate across the sulfate-bicarbonate or bicarbonate-sulfate class and from calcium-magnesium across sodium-calcium-magnesium reverse calcium-magnesium group. Total dissolved solids (TDS) increase by a factor of 4.0–4.7 between the upper and mouth of the river. The dissolved and suspended loads were studied in the mixing zone of acid mine and river water. The different hydrochemistry characteristics may result from Fe, Al, and Mn hydroxide precipitation. The pH values and dissolved oxygen cycles could change the uptake of heavy metals on suspended iron and manganese oxides, and the mechanism of removing it in water. River particulates have the potential of regulating heavy metal inputs to aquatic systems from pollution. The ore elements or the heavy metals are removed from the water in two ways: by the runoff of Modonkul and the sedimentation of suspended material at the bottom. The inflow of mine water into the Modonkul river leads to the rare earth elements (REEs) composition with negative cerium and positive europium anomalies.

Аннотация: Рассмотрены геологические условия формирования азотных термальных источников в пределах Икатского хребта.Выходы источников находятся как в

Алифатические углеводороды углекислых минеральных и азотных

The paper discusses water–rock interaction in areas where wastes of tungsten ore processing are stored, as exemplified by the Dzhida and Bom-Gorkhon mining and processing complexes. Pore waters at the tailing dumps become acidic, and the solutions are enriched in decomposition products of the sulfide minerals and rocks. When the wastes are stored for a long enough time, interaction between the acidic solutions and rocks hosting ore mineralization leads to water enrichment in HREE. The paper presents data on the neutralizing properties of limestone. REE are demonstrated to be able to enrich interaction products of the acidic waters and limestone in the form of newly produced amorphous mineral phases.