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This study was the first attempt to identify the sources of total oxidized nitrogen (TON) and inorganic phosphorus (IP) in the water of the Selenga River—the main tributary of Lake Baikal. To identify TON and IP sources, the data on nutrient concentrations in water of Selenga River and its tributaries as well as the data on river runoff were collected and mapped. On the basis of the obtained data, the values of TON and IP exported from different parts of Selenga watershed were evaluated and mapped using geospatial techniques. In addition, critical source areas (CSAs) which accumulate soil pollutants from nonpoint pollution sources and release them into the surface water during storm events were identified in most polluted watershed areas. It was found that the values of TON exports in most parts of the Selenga watershed varied in the range 0–50 kg/km2/yr, whereas the values of IP exports varied in the range 0–5 kg/km2/yr. Obtained data on TON export were in agreement with those obtained earlier by foreign researchers using global models of nutrient export, whereas data on IP exports were two times higher than those previously modelled. [ABSTRACT FROM AUTHOR]

The aim of this study was the systematization and generalization of data obtained by authors during the last decade and the comparison of these data with those obtained by other authors. Gas chromatography (GC-MS) was used for the determination of PAHs and the positive matrix factorization (PMF) model and principal component analysis (PCA) were used for source apportionment of PAHs. It was found that the total concentration of 16 priority PAHs in surface waters varied from 5 to 200 ng/L, whereas the concentration of 16 PAHs in bottom sediments varied from 50 to 700 ng/g. The 2–3-ring PAHs were dominant in water, whereas the 4–6-ring PAHs were dominant in sediments. That was due to PAHs fractionation in the soil–water system. The source apportionment results showed that the PAHs in both water and sediments mostly originated from the combustion of biomass and fossil fuels. In contrast to sediments, there was a PAH fraction in water that did not originate from a single source. The pollution of freshwater ecosystems manifested itself in the lack of correlation between values of octanol/water partitioning coefficients and sediment/water partitioning coefficients of PAHs. [ABSTRACT FROM AUTHOR]

The article suggests design principles of an advanced onboard computer network with an intelligent control system. It describes the main advantages of designing an onboard computer network based on fibre optics, which allows the implementation of an integrated intellectual system performing intelligent inference in emergency situations. The suggested principles significantly increase the reliability and fault tolerance of avionics suits, which, in turn, enhances flight safety. The suggested concept aims to solve a number of important problems including the design of a switchless computing environment, the development of the methods for dynamic reconfiguration of avionics suits with such an environment, and the implementation of a specialised multilevel intelligent avionics system within this environment. [ABSTRACT FROM AUTHOR]

Pesticides are widely used in agriculture as a pest control strategy. Despite the benefits of pesticides on crop yields, the persistence of chemical residues in soil has an unintended impact on non-targeted microorganisms. In the present study, we evaluated the potential adverse effects of a mixture of fungicides (difenoconazole, epoxiconazole, and kresoxim-methyl) on soil fungal and bacterial communities, as well as the manifestation of wheat diseases. In the fungicide-treated soil, the Shannon indices of both fungal and bacterial communities decreased, whereas the Chao1 indices did not differ compared to the control soil. Among bacterial taxa, the relative abundances of Arthrobacter and Sphingomonas increased in fungicide-treated soil due to their ability to utilize fungicides and other toxic compounds. Rhizopus and plant-beneficial Chaetomium were the dominant fungal genera, with their prevalence increasing by 2–4 times in the fungicide-treated soil. The genus Fusarium, which includes phytopathogenic species, which are notably responsible for root rot, was the most abundant taxon in each of the two conditions but its relative abundance was two times lower in fungicide-treated soils, consistent with a lower level of disease incidence in plants. The prediction of metabolic pathways revealed that the soil bacterial community had a high potential for degrading various pollutants, and the soil fungal community was in a state of recovery after the application of quinone outside inhibitor (QoI) fungicides. Fungicide-treated soil was characterized by an increase in soil microbial carbon, compared with the control soil. Collectively, the obtained results suggest that the application of difenoconazole, epoxiconazole, and kresoxim-methyl is an effective approach for pest control that does not pose a hazard for the soil ecosystem in the short term. However, it is necessary to carry out additional sampling to take into account the spatio-temporal impact of this fungicide mixture on the functional properties of the soil. [ABSTRACT FROM AUTHOR]

In this article, a model of an energy harvester, the mechanical part of which is an inverted pendulum, is proposed. We investigated the stability of a linearized system. It was proven that the stabilizing control of the pendulum, based on the feedback principle, enables the stabilization of the system. We have identified the zones of stability and the amplitude–frequency characteristics. In the second part of this article, a generalization of the dynamic system for the case of the hysteresis friction in the mechanical joint is considered. The role of nonlinear effects within the design Preisach model and the phenomenological Bouc–Wen model is shown. [ABSTRACT FROM AUTHOR]

The genus Fusarium includes many pathogenic species causing a wide range of plant diseases that lead to high economic losses. In this review, we describe how the Fusarium taxonomy has changed with the development of microbiological methods. We specify the ecological traits of this genus and the methods of its identification in soils, particularly the detection of phytopathogenic representatives of Fusarium and the mycotoxins produced by them. The negative effects of soil-borne phytopathogenic Fusarium on agricultural plants and current methods for its control are discussed. Due to the high complexity and polymorphism of Fusarium species, integrated approaches for the risk assessment of Fusarium diseases are necessary. [ABSTRACT FROM AUTHOR]

Critical source areas (CSAs) are the areas prone to generating runoff and are characterized by a high level of soil pollution. CSAs may accumulate and release soil pollutants emitted by primary emission sources (industrial and municipal enterprises) into the surface water during storm events. The aim of this study was to identify CSAs and their pollution sources and to assess the level of soil pollution in CSAs with polycyclic aromatic hydrocarbons (PAH) and trace metals (TM). CSAs were identified using a geospatial data model (GIS), and primary emission sources were identified using a positive matrix factorization (PMF) model. It was found that the soils of CSAs were characterized by higher pollution levels than soils outside the CSAs. Pollution levels were highly variable among the identified CSAs due to the different capacities of the plants located in those areas. Due to high variability of TM concentrations in preindustrial soils, the pollution level of PAHs and the pollution level of TMs in CSA soils did not correlate with each other. The PAH composition of bottom sediments was different from that of soils, whereas the TM compositions of the soils and bottom sediments were similar. It was proved that the main sources of PAHs and TMs in CSA soils were traffic emissions and central heating boilers. [ABSTRACT FROM AUTHOR]

The article considers a hysteretic model of consumer behaviour in mono-product markets. Demand generation with regard to an individual consumer is modeled using a non-ideal relay with inverted thresholds. Therefore, the sales rate is defined as an analogue of the Preisach converter. The article considers the problem of the optimal production, storage, and distribution of goods, taking into account the hysteretic nature of the demand curve. The problem is reduced to a non-classical optimal control problem with hysteretic non-linearities. The latter is solved using Pontryagin's maximum principle. The adopted economic model is based on the binary relationship of consumers to the product: the product is bought or the product is not bought. Transitions between these states are determined within the framework of our model only by the price of the goods; therefore, only the operator of a non-ideal relay can accurately describe such a dependence. The article presents the results of computational experiments illustrating the theoretical assumptions. [ABSTRACT FROM AUTHOR]

Acute lung injury (ALI) as a model of acute respiratory distress syndrome is characterized by inflammation, complex coagulation, and hematologic abnormalities which result in the formation of fibrin-platelet microthrombi in the pulmonary vessels with the rapid development of progressive respiratory dysfunction. We hypothesize that a nebulized fibrinolytic agent, non-immunogenic staphylokinase (nSta), may be useful for ALI therapy. First, the effect of the nebulized nSta (0.2 mg/kg, 1.0 mg/kg, or 2.0 mg/kg) on the coagulogram parameters was studied in healthy rats. ALI was induced in mice by nebulized administration of lipopolysaccharide (LPS) at a dose of 10 mg/kg. nSta (0.2 mg/kg, 0.4 mg/kg or 0.6 mg/kg) was nebulized 30 min, 24 h, and 48 h after LPS administration. The level of pro-inflammatory cytokines was determined in the blood on the 8th day after LPS and nSta administration. The assessment of lung damage was based on their weighing and microscopic analysis. Fibrin/fibrinogen deposition in the lungs was determined by immunohistochemistry. After nSta nebulization in healthy rats, the fibrinogen blood level as well as activated partial thromboplastin time and prothrombin time did not change. In the nebulized ALI model, the mice showed an increase in lung weight due to their edema and rising fibrin deposition. An imbalance of proinflammatory cytokines was also found. Forty percent of mice with ALI without nSta nebulization had died. Nebulized nSta at a dose of 0.2 mg/kg reduced the severity of ALI: a decrease in interstitial edema and inflammatory infiltration was noted. At a dose of 0.4 mg/kg of nebulized nSta, the animals showed no peribronchial edema and the bronchi had an open clear lumen. At a dose of 0.6 mg/kg of nebulized nSta, the manifestations of ALI were completely eliminated. A significant dose-dependent reduction of the fibrin-positive areas in the lungs of mice with ALI was established. Nebulized nSta had a normalizing effect on the proinflammatory cytokines in blood— interleukin (IL)-1α, IL-17A, IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF). These data showed the effectiveness of nebulized nSta and the perspectives of its clinical usage in COVID-19 patients with acute respiratory distress syndrome (ARDS). [ABSTRACT FROM AUTHOR]

Positive matrix factorization (PMF) is a widely used multivariate source apportionment technique. However, PMF-derived source profiles are never compared to real ones because of the absence of data on the chemical composition of source emissions. The aim of this study was to verify the validity of PMF-derived source profiles using the diagnostic ratios (DR) method and end-member mixing analysis (EMMA). The composition of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM) sampled in the air above Lake Baikal in summer and the composition of inorganic elements (IE) in PM accumulated in Lake Baikal snowpack were used as study objects. Five PAH sources and five IE sources were identified using PMF. Eight PAHs and six IEs selected from PMF-derived source profiles were recognized as eligible for calculating the DRs (species 1/(species 1 + species 2)) suitable for testing PMF results using EMMA. EMMA was based on determining whether most samples in mixing diagrams that use DR values as coordinates of source points could be bound by a geometrical shape whose vertices are pollution sources. It was found that the four PAH sources and four IE sources obtained using PMF were also identified using EMMA. Thus, the validity of the most of PMF-derived source profiles was proved. [ABSTRACT FROM AUTHOR]

Fungi represent a diverse group of organisms that play an essential role in maintaining soil health and ecosystem functioning. Plant root exudates form nutrient-rich niches that harbor specific fungal communities, or so-called rhizosphere mycobiomes. The long-term application of fertilizers supplies the soil with nutrients that may override the plant-related effects on rhizosphere fungal communities. Here, we assessed the effect of contrasting fertilization regimes on the composition, diversity, and abundance of bulk soil and rhizosphere mycobiomes of potato, white mustard, and maize under NPK (mineral fertilizers) or fresh cattle manure (organic fertilizers). Mineral and organic fertilizers led to distinct fungal communities in the rhizospheres of all studied crops, and the plant-related effects on the mycobiome were overridden by the effect of fertilization. The abundances of Ascomycota and Olpidiomycota were higher under manure, while the abundances of Basidiomycota and Monoblepharomycota increased under NPK. Manure input strongly increased fungal abundance but decreased fungal diversity and the total number of species. NPK had a slight effect on fungal diversity, but significantly increased the relative abundances of fungal phytopathogens, such as Alternaria and Fusarium. Our study shows that that potential plant species effects on the abundance and diversity of the rhizosphere mycobiomes are governed by long-term fertilization. Fertilization management could therefore be used to manipulate rhizosphere fungal communities and soilborne pathogen suppressiveness. [ABSTRACT FROM AUTHOR]

Plants, fungi, bacteria and protozoa are highly interconnected in constructed wetlands. These heterogeneous groups of organisms constitute a single system with complex internal trophic interactions. Thus, the joint activity of micro- and macroorganisms in constructed wetlands provides highly efficient wastewater treatment: both nutrients and complex organic substances can be effectively removed in branched trophic chains. The bacterial community of constructed wetlands has recently received much attention, while the fungal component remains less studied, particularly saprotrophic fungi. This paper reveals a taxonomic analysis of the cultivated saprotrophic fungi combined with the bacterial community in vertical flow constructed wetlands (VSCWs) operated by the Azoé-NP® process. These systems have unique features to affect the microbial community, which results in a high treatment efficiency and nitrogen removal. There are very few studies of saprotrophic fungi in VFCWs, while this work shows their abundance and diversity in VFCWs. We found 62 species of cultivated microscopic fungi and described the taxonomic composition of bacterial and fungal community at all wastewater treatment stages. In the studied VFCWs, we identified the species of micromycetes, which proved effective in the removal of contaminants. The data obtained can provide a deeper insight into the characteristics of Azoé-NP® systems and the treatment processes occurring in constructed wetlands. [ABSTRACT FROM AUTHOR]

The effect of an external electric field and dissipative tunneling on the spectral intensity of recombination radiation in a quantum dot with an A+ + e impurity complex (a hole localized on a neutral acceptor interacting with an electron localized in the ground state of the quantum dot) is studied in the zero-radius potential model in the adiabatic approximation. The probability of dissipative tunneling of a hole is calculated in the one-instanton approximation. A high sensitivity of the recombination radiation intensity to the strength of the external electric field and to such parameters of the surrounding matrix (dissipative tunneling parameters) as temperature, the constant of interaction with the contact medium (or the heat-bath), and the frequency of phonon modes, has been revealed. It is shown that an external electric field leads to a shift of the recombination radiation threshold by several tens of meV, and a change in the parameters of dissipative tunneling has a noticeable effect on the spectral intensity of recombination radiation. It is shown that the resonant tunneling effect manifests itself in the form of "dips" in the field dependence of the spectral intensity of recombination radiation, which occur at certain values of the external electric field strength and temperature. This opens up certain prospects for the use of the considered system "quantum dot—impurity complex A+ + e" under conditions of dissipative tunneling for the study and diagnostics of biological objects. [ABSTRACT FROM AUTHOR]

The collapse of collective farming in Russia after 1990 led to the abandonment of 23% of the agricultural area. Microbial biomass is a transit pool between fresh and soil organic matter; therefore, structural changes in soil microbial community determine the carbon cycle processes caused by self-restoration of arable lands after abandonment. Here, we assessed the influence of monthly changes in moisture and temperature on the bacterial community structure and abundance in Retisols under long-term abandoned cropland. Two periods with pronounced differences in bacterial properties were revealed: the growing period from March to September and the dormant period from October to February. The growing period was characterized by higher bacterial abundance and diversity compared to the dormant period. The relative abundances of the bacterial community dominants (Alpha-, Gamma- and Deltaproteobacteria, subgroup 6 of phylum Acidobacteria) did not change significantly over the year, either in total or active communities. The relative abundances of Bacteroidetes and Verrucomicrobia increased in the growing period, whereas Actinobacteria and Chloroflexi were more abundant in the dormant period. The microbial gene abundances positively correlated with soil and air temperature, but not with soil moisture. Thus, the seasonal dynamics of soil microbial communities are closely related to soil temperature and should be considered when assessing carbon cycles in abandoned lands. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify particulate matter (PM) sources and to evaluate their contributions to PM in the snowpack of three East Siberian cities. That was the first time when the PM accumulated in the snowpack during the winter was used as the object for source apportionment study in urban environment. The use of long-term integrated PM samples allowed to exclude the influence of short-term weather conditions and anthropogenic activities on PM chemistry. To ascertain the real number of PM sources and their contributions to air pollution the results of source apportionment using positive matrix factorization model (PMF) were for the first time compared to the results obtained using end-member mixing analysis (EMMA). It was found that Si, Fe and Ca were the tracers of aluminosilicates, non-exhaust traffic emissions and concrete deterioration respectively. Aluminum was found to be the tracer of both fossil fuel combustion and aluminum production. The results obtained using EMMA were in good agreement with those obtained using PMF. However, in some cases, the non-point sources identified using PMF were the combinations of two single non-point sources identified using EMMA, whereas the non-point sources identified using EMMA were split by PMF into two single non-point sources. The point sources were clearly identified using both techniques. [ABSTRACT FROM AUTHOR]

Simple Summary: The Qinghai–Tibet Plateau is known as the "third pole of the world". Due to the extreme geographical location, Qinghai–Tibet Plateau has unique ecosystems characterized by oxygen deficiency, low temperature, high salinity and alkalinity. We carried out the current study to explore the excellent extremophilic Bacillus strains via potential stress resistance as well as biocontrol properties in the Qinghai–Tibet Plateau. We found a Bacillus halotolerans strain with a promising ability to withstand harsh environments and which also exhibits an optimistic biocontrol activity against plant pathogens. We revealed the whole genome sequencing and its taxonomic position and elucidated its molecular functions that were responsible for enhancing stress tolerance as well as suppressing plant pathogens at the genetic level. Lastly, we identified this strain harbored the specific genes associated with stresses resistance, biocontrol function, and can be used as a biological agent in the agriculture field. Due to its topographical position and climatic conditions, the Qinghai–Tibet Plateau possesses abundant microorganism resources. The extremophilic strain KKD1 isolated from Hoh Xil possesses strong stress tolerance, enabling it to propagate under high salinity (13%) and alkalinity (pH 10.0) conditions. In addition, KKD1 exhibits promising biocontrol activity against plant pathogens. To further explore these traits at the genomic level, we performed whole-genome sequencing and analysis. The taxonomic identification according to the average nucleotide identity based on BLAST revealed that KKD1 belongs to Bacillus halotolerans. Genetic screening of KKD1 revealed that its stress resistance mechanism depends on osmotic equilibrium, membrane transportation, and the regulation of ion balance under salt and alkaline stress. The expression of genes involved in these pathways was analyzed using real-time quantitative PCR. The presence of different gene clusters encoding antimicrobial secondary metabolites indicated the various pathways by which KKD1 suppresses phytopathogenic growth. Moreover, the lipopeptides surfactin and fengycin were identified as being significant antifungal components of KKD1. Through comparative genomics analysis, we noticed that KKD1 harbored specific genes involved in stress resistance and biocontrol, thus providing a new perspective on the genomic features of the extremophilic Bacillus species. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain a detailed picture of the origin of the anthropogenic and natural inorganic solutes in the surface waters of the Lake Baikal watershed using limited data on solute sources. To reveal the origin of solutes, the chemical composition of water was considered as a mixture of solutes from different sources such as rocks and anthropogenic wastes. The end-member mixing approach (EMMA), based on the observation that the element ratios in water uncorrelated with one another are those that exhibit differences in values across the different types of rocks and anthropogenic wastes, was used for source apportionment. According to the results of correlation analysis, two tracers of sources of most abundant ions present in riverine waters were selected. The first tracer was the ratio of combined concentration of calcium and magnesium ions to concentration of potassium ion ((Ca2+ + Mg2+)/K+), and the second tracer was the ratio of sulfate and bicarbonate ion concentrations (SO42−/HCO3−). Using these tracers, three sources of main ions in water, such as sulfide-bearing silicate rocks, non-sulfide silicate rocks and carbonate rocks, were apportioned. The results of cluster analysis showed the possibility of using the ratios of strontium, iron, manganese, molybdenum, nickel, and vanadium concentrations (Sr/Fe, Sr/Mn, Ni/V, Mo/V) as tracers of the trace element sources. The use of these tracers and the obtained data on sources of main ions showed the possibility of identifying the natural trace element sources and distinguishing between natural and anthropogenic trace element sources. [ABSTRACT FROM AUTHOR]

We studied cell proliferation in the postnatal mouse brain between the ages of 2 and 30 months and identified four compartments with different densities of proliferating cells. The first identified compartment corresponds to the postnatal pallial neurogenic (PPN) zone in the telencephalon; the second to the subpallial postnatal neurogenic (SPPN) zone in the telencephalon; the third to the white matter bundles in the telencephalon; and the fourth to all brain parts outside of the other three compartments. We estimated that about 3.4 million new cells, including 0.8 million in the subgranular zone (SGZ) in the hippocampus, are produced in the PPN zone. About 21 million new cells, including 10 million in the subependymal zone (SEZ) in the lateral walls of the lateral ventricle and 2.7 million in the rostral migratory stream (RMS), are produced in the SPPN zone. The third and fourth compartments together produced about 31 million new cells. The analysis of cell proliferation in neurogenic zones shows that postnatal neurogenesis is the direct continuation of developmental neurogenesis in the telencephalon and that adult neurogenesis has characteristics of the late developmental process. As a developmental process, adult neurogenesis supports only compensatory regeneration, which is very inefficient. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are complicated ecosystems that include vegetation, sediments, and the associated microbiome mediating numerous processes in wastewater treatment. CWs have various functional zones where contrasting biochemical processes occur. Since these zones are characterized by different particle-size composition, physicochemical conditions, and vegetation, one can expect the presence of distinct microbiomes across different CW zones. Here, we investigated spatial changes in microbiomes along different functional zones of a free-water surface wetland located in Moscow, Russia. The microbiome structure was analyzed using Illumina MiSeq amplicon sequencing. We also determined particle diameter and surface area of sediments, as well as chemical composition of organic pollutants in different CW zones. Specific organic particle aggregates similar to activated sludge flocs were identified in the sediments. The highest accumulation of hydrocarbons was found in the zones with predominant sedimentation of fine fractions. Phytofilters had the highest rate of organic pollutants decomposition and predominance of Smithella, Ignavibacterium, and Methanothrix. The sedimentation tank had lower microbial diversity, and higher relative abundances of Parcubacteria, Proteiniclasticum, and Macellibacteroides, as well as higher predicted abundances of genes related to methanogenesis and methanotrophy. Thus, spatial changes in microbiomes of constructed wetlands can be associated with different types of wastewater treatment processes. [ABSTRACT FROM AUTHOR]

The aim of this study was to select chemical species characterized by distinctly different proportions in natural and anthropogenic particulate matter that could be used as tracers for air pollutant sources. The end-member mixing approach, based on the observation that the chemical species in snow closely correlated with land use are those that exhibit differences in concentrations across the different types of anthropogenic wastes, was used for source apportionment. The concentrations of Si and Fe normalized to Al were used as tracers in the mixing equations. Mixing diagrams showed that the major pollution sources (in descending order) are oil, coal, and wood combustion. The traces of several minor sources, such as aluminum production plants, pulp and paper mills, steel rust, and natural aluminosilicates, were also detected. It was found that the fingerprint of diesel engines on snow is similar to that of oil combustion; thus, future research of the role of diesel engines in air pollution will be needed. The insufficient precision of source apportionment is probably due to different combinations of pollution sources in different areas. Thus, principles for the delineation of areas affected by different source combinations should be the subject of further studies. [ABSTRACT FROM AUTHOR]

The removal of trace metals (TM), dissolved organic carbon (DOC), mineral nitrogen (Nmin.), and polycyclic aromatic hydrocarbons (PAHs) from the water of Lake Baikal and its tributaries was evaluated. The contaminant removal rate (CRR) and the contaminant removal capacity (CRC) were used as water self-purification parameters. The CRR was calculated as the difference between contaminant mass flow rates at downstream and upstream gauging stations. The CRC was calculated as the quotient of the CRR and the change in water discharge between downstream and upstream gauging stations. Whether the CRR and CRC have positive or negative values depends on whether contaminant release or removal occurs in the water body. The CRR depends on the size of the water body. The lowest and the highest CRRs observed for Baikal were equal to −15 mg/s (PAHs) to −7327 g/s (DOC), whereas the highest PAH and DOC removal rates observed for Selenga River (the major Baikal tributary) in summer were equal to −9 mg/s and −3190 g/s correspondingly. The highest PAH and DOC removal rates observed for small tributaries were equal to 0.0004 mg/s and −0.7 g/s respectively. The amplitude of annual CRR oscillations depends on contaminant abundance. The highest amplitude was typical for most abundant contaminants such as Nmin. and DOC. In unpolluted sections of the Selenga River the highest rates of N and C removal (−85 g/s and −3190 g/s, respectively) were observed in summer and the lowest rates (4 g/s and 3869 g/s, respectively) were observed in the spring. The lowest amplitude was typical for PAHs and some low-abundance TM such as V and Ni. The highest summer rates of V and Ni removal were equal to −378 mg/s and −155 mg/s respectively, whereas lowest spring rates are equal to 296 mg/s and 220 mg/s. The intermediate CRR amplitudes were typical for most abundant TM such as Sr, Al, and Fe. The spatial CRR variability depends on water chemistry and the presence of pollution sources. The lowest (up to 38 g/s) rates of Nmin. removal was observed for polluted lower Selenga sections characterized by low water mineralization and high DOC concentrations. The highest rates (−85 g/s) were observed for unpolluted upper sections. Seepage loss from the river to groundwater was also recognized as an important means of contaminant removal. The CRC values depend mostly on water residence time. The DOC removing capacity value of Baikal (−26 g/m3) were lower than those of Selenga in summer (−35 g/m3) but higher than the CRCs of all tributaries during the other seasons (from 30 mg/m3 to −10 g/m3). [ABSTRACT FROM AUTHOR]