This study examines the contamination levels and sources of 32 metals and metalloids (MMs) in environmental compartments (roadside soil, road dust, and river suspended sediments) of a small urbanized river catchment located in Moscow megacity. MMs partitioning between particle size fractions (PM1000, PM1-10, and PM1) was analyzed by ICP-MS and ICP-AES methods. The pollution level of particle size fractions with MMs decreases in the following series: road dust > suspended sediments > soils. Absolute principal component analysis with multiple linear regression (PCA/APCS-MLR) shows that in both relatively coarse (PM1-10) and fine (PM1) fractions, traffic emissions are the primary contributors to pollution, whereas natural sources are dominant providers of chemical elements in bulk samples (PM1000). The predominance of fractions with a diameter over 10 mu m in all three studied compartments indicates that the mineral matrix of all compartments is formed predominantly by natural material. Across all compartments and their fractions, Sb, Cd, Zn, Mo, W, Sn, Cu, Pb, and Bi are consistently accumulated. PM1 and PM1-10 particles of road dust and suspended sediments also absorb Ni and Cr, suspended sediments retain Mn and As, and soils additionally accumulate As. Anthropogenic influence is more pronounced in PM1 and PM1-10 particles compared to bulk samples due to a large impact of industrial sources, traffic, construction activities, and waste storage. Polluted soils are an additional source of MMs to PM1 and PM1-10 of road dust and PM1-10 of suspended sediments, and road dust acts as a source of MMs to PM1-10 of soils.

Coal-fired thermal power plants remain one of the primary sources of electricity generation in the Asian part of Russia. However, coal combustion leads to severe environmental pollution. This study attempts to assess this impact in a large city in Eastern Siberia, Ulan-Ude, the capital of Buryatia, where coal is widely used in thermal power plants and for stove heating. The accumulation of trace metals (MMs) in the upper soil horizons, road dust, and their fine PM10 fraction was evaluated. The coal, ash, soil and road dust samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS/AES) to determine concentrations of As, Bi, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Sr, V, W, and Zn. The coal was enriched only in Sr compared to world coals, while the ash was depleted in all these MMs. Concentrations of all MMs were higher than the local natural soil background values, with priority pollutants in Ulan-Ude's soils identified as Cu, Pb, Sb, Cd, Zn, and W. For the first time, the primary sources of MMs were quantitatively assessed using the PMF receptor model. It was established that most MMs (As, Ni, Cr, Sr, V, Co, Bi) originated from mixed sources, including natural sources and emissions from coal combustion. Its contribution accounted for 32.6 % for the bulk soils and 25.4 % for the PM10 fraction. The contribution of exhaust and non-exhaust emissions was estimated as 19.2 % and 22.4 % for bulk soils and the PM10 fraction, respectively. The spatial distribution of the Total Pollution Index (TPI) for soils indicated that the pollution degree was highest in private residential areas (mean TPI = 24), suggesting an influence of coal combustion conditions (including temperature) on contamination levels. The PM10 fraction of soil was most polluted in the railway transport zone (mean TPI = 46). Approximately 8 % of Ulan-Ude's territory displayed maximum, extremely hazardous levels of pollution in soils and their PM10 fraction, posing a risk to human health. Road dust was enriched in Sr, Sb and Pb compared to the continental upper crust values. Bulk road dust exhibited a low level of pollution, while the Total Pollution Index for its PM10 fraction reached an extremely hazardous level (TPI > 128). The highest pollution levels in road dust and its PM10 fraction were observed on main roads. In large industrial cities, pollution from coal combustion occurs alongside other significant sources, including vehicular emissions, contributing to the diversity of total pollutant emissions.

The content of 39 metals and metalloids (MMs) in submicron road dust (PM1 fraction) was studied in the traffic zone, residential courtyards with parking lots, and on pedestrian roads in parks in Moscow. The geochemical profiles of PM1 vary slightly between different types of roads and courtyards but differ significantly from those in parks. In Moscow, compared to other cities worldwide, submicron road dust contains less As, Sb, Mo, Cr, Cd, Sn, Tl, Ca, Rb, La, Y, U, but more Cu, Zn, Co, Fe, Mn, Ti, Zr, Al, V. Relative to the upper continental crust, PM1 is highly enriched in Sb, Zn, Cd, Cu, W, Sn, Bi, Mo, Pb. In the courtyards, where contact between pollutants and the population is most frequent and occurs over an extended period, the level of PM1 pollution with MMs (from strong to extreme) is comparable to that on large roads. Source identification was conducted using correlations, elemental ratios, and absolute principal component analysis with multiple linear regression (APCA-MLR). In the traffic zone, non-exhaust and exhaust vehicle emissions contribute significantly to the MM concentrations in PM1 (especially for Bi, Sb, Sn, V, Fe, Cu, W, Mo); soil particles, abrasion of steel surfaces, industrial emissions, tire and road wear with carbonate dust resuspension contribute less. In the courtyards, the contribution of the road wear with carbonate dust resuspension and soil particles increases by up to 16

Soil mapping of urban areas is required for solving many applied problems. However, its methodology is still under development. The lack of information about urban soils and the inconsistence of their classifications are the main difficulties, as well as the intricate soil cover patterns in cities and towns. The research was aimed to compile the soil map for the drainage basin of the small urban river Setun at a scale that could reflect its soil cover heterogeneity. Some new approaches to the differentiation of urban and semi-urban soils in accordance with recent ideas on their systematic and land use variants have been proposed. The concept of pedo-urbo-mosaics, which implements the soil cover pattern theory in relation to urbanized territory, has been used for delineating mapping units. The compilation methodology involved the use of open spatial data and GIS technologies. The subdivision of the basin into mapping units was performed using ©OpenStreetMap data and Yandex Maps Web mapping service. Spatial analysis in GIS allowed for mapping the territory with a moderate urbanization rate on a large scale, obtaining a more adequate and detailed spatial representation of the area than in the case of applying the traditional approach. The map, at a scale of 1:60,000 contains 16 natural/semi-natural soils and technogenic superficial formations, as well as 11 pedo-urbo-mosaics. The study may be of methodological interest as an experience in soil mapping of urbanized areas using GIS.

Cities are highly interconnected systems where specific interactions between various urban environments occur due to the Urban Heat Island (UHI) and Urban Pollution Island (UPI) effects. Four compartments of the environment (atmospheric air, road dust, streamflow, and people) are discussed for Moscow city. Long-term meteorological, radiative, air quality, and precipitation measurements, the non -hydrostatic regional numerical COSMO model, and extensive hydrological and geochemical sampling were used. To characterize mortality and UPI interaction, a family of distributed lag non-linear models (DLNM) was applied. The study reveals increased aerosols concentrations which reduce the incoming solar radiation and increase the atmospheric longwave radiation. UHI strengthens the low -troposphere convergence due to urban breeze circulation and atmospheric circulation due to elevated surface roughness, the effect which leads to 11.6% heaviest precipitation increase compared to background values. Increased precipitation doubles streamflow rates and enhances the contribution of rain floods to annual flow. Similar geochemical associations with Sb, W, Zn, Cd, Pb, and Cu were found in aerosol PM 10 , indicating transport and road dust impact. Finally, associations between high temperatures and human mortality which are generally stronger at high levels of air pollution for both PM 10 and NO 2 , and for lag 1 day and 2-6 days are discussed.

The content of 17 individual polycyclic aromatic hydrocarbons (PAHs) was analyzed in samples of background and urban soils obtained during a geochemical survey of the territory of Ulan-Ude in the summer of 2022 for the first time. The average content of PAHs in the urban soils is 801 ng/g, which is more than 8.5 times higher than the level in background chestnut soils. The soil cover is contaminated primarily with medium- and high-molecular-weight PAHs. The proportions of individual PAHs in the soils of Ulan-Ude range within 4–11

: For the first time, polycyclic aromatic hydrocarbons (PAH) contamination of the soil cover of Ulan-Ude, the capital of the Republic of Buryatia, was studied. The content of 16 individual polyarenes was analyzed in the upper horizon of background chestnut and urban soils, sampled during soil and geochemical survey in July–August 2022. The average concentration of total PAHs in the soil cover of Ulan-Ude was 735 ng/g, which was 8 times as much as the concentration in the background soils (87 ng/g). The PAH amount in the soil of various functional zones decrease in the following order: railway transport > motor traffic > industrial > one-story residential > multi-story residential > recreational. At the same time, the amount of PAHs in the railway transport zone was 2.6–5.2 times higher than in other functional zones, which indicates that railway transport is the most powerful source of PAHs in the city. Contamination of soils with polyarenes in all functional zones is determined primarily by medium- (46%) and high-molecular-weight (41%) compounds. Among PAHs with low molecular weight, phenanthrene prevailed (9% of the total PAHs), but medium-molecular-weight fluoranthene (18%) and pyrene (13%) showed higher share; high-molecular-weight compounds dominated by benzo(ghi)perylene (12%), benzo(b)fluoranthene (10%), indeno(1,2,3-cd)pyrene (8%) and benzo(a)pyrene (6%). The total amount of 16 PAHs in the soil cover of the city varied within the range of 17–9 540 ng/g. The highest levels of pollution (3 226–9 540 ng/g) were recorded at 9 sampling points (4% of the city), which form the most contrasting local PAH anomalies. In more than half of the territory of Ulan-Ude, the total amount of PAHs did not exceed 500 ng/g. The indicator ratios of individual PAHs made it possible to determine the dominant types of sources, which include railway transport and coal combustion. The contribution to the environmental hazard of soil contamination with PAHs in Ulan-Ude was mainly made by benzo(a)pyrene (64%) and, to a lesser extent, by benzo(b)fluoranthene (9.6%), indeno(1,2,3-cd)pyrene (7.2%), dibenzo(ah)anthracene (6.5%) and benzo(a)anthracene (6.1%).

High population and a wide range of activities in a megacity lead to large-scale ecological consequences which require the assessment with respect to distinct characteristics of climate, location, fuel consumption, and emission sources. In-depth study of aerosol characteristics was carried out in Moscow, the largest megacity in Europe, during the cold period (autumn and winter) and in spring. PM10 chemical speciation based on carbonaceous matter, water-soluble ions, and elements was carried out to reconstruct the PM mass and evaluate the primary and secondary aerosol contribution. For the whole study period organic matter, mineral dust, and secondary inorganic/organic accounted for 34, 24, and 16 % of PM10 mass, respectively. PM10, OC, and EC approached a maximum in spring and decreased in winter. Mineral dust seasonal fraction increased from spring (17 %) to autumn (32 %), and then decreased in winter (22 %). Secondary inorganic aerosols (SIA) in opposite showed the maximum 27 % in winter. K+ marked the residential biomass burning in the region surrounding a megacity in spring and autumn, agriculture fires in spring. In winter primary aerosol contribution dropped down 56 % while secondary approached practically equal 44 %. Source factors with the relative contributions are quantified, namely city dust (26 %), traffic (23 %), industrial (20 %), biomass burning (12 %), secondary (12 %), and de-icing salt (7 %); they were significantly varying between the cold heating period and springtime. The relevance of sources to meteorological parameters and mass transportation is investigated by using both bivariate polar plots and Lagrangian integrated trajectory (HYSPLIT) model. Trajectory clustering demonstrates regional sources being crucial contributors to PM10 pollution. Aerosol speciation and source apportion factors identify the differences of the Moscow urban background among large European and Asian cities due to northern climate conditions, fast construction, long-range transport from industrial -developing area surrounding a city, regional biomass burning preferably in spring and autumn, and winter road management.

An indicator of urban environmental pollution can be road dust, which is formed by the participation of many anthropogenic sources. For Moscow, the main source of heavy metals and metalloids (HMMs) is motor transport which emissions are toxic. Pollutants in fine fractions of road dust are easily blown into the air, then enter the human body and pose a health risk. This work is devoted to assessing the spatial distribution and environmental hazard of HMMs accumulation in road dust and its fine fractions PM1-10 and PM1 in the Central Administrative Okrug (CAO) of Moscow based on field data for 2023. The list of priority pollutants coming with technogenic emissions in the CAO includes Sb, Zn, Cu, and Cd, as well as Sn, Pb, Mo, and W. In fine fractions, the mean content of these HMMs is an order of magnitude higher; its variability is lower, while the differences in the contents of the elements in dust from roads with various traffic intensities become more contrasting. Differences between the roads are caused by intensity, average speed, and mode of the traffic, as well as by the composition of the vehicle fleet and the frequency of traffic jams. Extremely high and dangerous pollution in the PM1 fraction was found in about 85% of samples; the average for the okrug total pollution index for this fraction is 1.4 times higher than for the PM1-10 fraction.

Atmospheric precipitation acts as a significant pathway for pollutants from the atmosphere to the Earth’s surface, and analyzing urban precipitation data on intensity, fallout regime, transfer patterns, and solid particle content helps identify pollution sources. For the first time in the Moscow megacity, the levels of soluble forms of potentially hazardous elements (PHEs) in atmospheric precipitation were studied during the whole summer season of May–September 2019. The concentrations of Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cu, Fe, La, Li, Mn, Ni, P, Pb, Rb, Sb, Sn, Sr, and Zn were determined using inductively coupled plasma mass spectrometry and atomic emission spectroscopy methods. The research underscores the crucial role of atmospheric precipitation in washing PHEs out of the atmosphere. In May and September, concentrations of PHEs surpass the warm-season average. Notable contamination in May stems from elevated traffic during vacations, extensive burning of plant debris and wood, and pollen transport. Summer months are characterized by reduced forest and agricultural fires, traffic, and increased vegetation, leading to lower PHE concentrations, especially in July, with typical amount of precipitation contributing to pollutant dispersion. Elevated PHE levels in September are observed due to increased traffic load, biomass burning, and the expansion of unvegetated soil areas. Rainwater is enriched with Sb, Pb, Cd, Zn, Cu, B, Bi, P, and Sr, sourced from vehicle emissions, soil particles, industry, construction dust, biomass burning, and forest fires. Moderate enrichment with Ba, Mn, Ni, Co, and Sn also occurs episodically. Regression analysis highlights solid particles’ role as a major PHE source in rainwater, with the longer antecedent dry periods and the higher acidity level of rain intensifying the accumulation of PHEs. Long-range transport plays a lesser role, with Southern and Northern Europe, Western Siberia, and the central part of European Russia contributing meaningfully.

The pollution of the topsoil in the city of Baikal’sk (Irkutsk oblast) under the influence of industrial emissions and wastes of the Baikal Pulp and Paper Mill (BPPM) was studied. The contents of 16 individual polycyclic aromatic hydrocarbons (PAHs) in samples of urban and background soils taken during the soil geochemical survey in the summer of 2019 were analyzed. Relatively low contents of PAHs were found in lignin sludge from the BPPM and ash from the combined heat and power station (CHPS). The concentration of total PAHs in CHPS ash reaches 46 mg/kg with a predominance of low molecular weight compounds (the proportion of naphthalene and its homologues is 24

Relevance. The need to study the ecological state of the soil cover of industrial cities, which is the main depositing environment for technogenic emissions of heavy metals and metalloids, to identify the geochemical characteristics of the region and assess the impact on public health. Aim. To assess the sources and accumulation of heavy metals and metalloids in soils and their fraction PM10 in Severobaikalsk and to assess the risks associated with them for public health. Methods. Total content of Zn, As, Cd, Pb, Cr, Co, Ni, Cu, Sb, Mo, V, W, Sr, Bi in soil, coal and ash samples was determined by mass spectral and atomic emission methods with inductive-coupled plasma. Geochemical (KK, Kc, Zc), sanitary and hygienic (Ko) indicators were used. Health risks for adults and children were assessed. Principal component analysis was used. Results. In Severobaikalsk, the priority soil pollutants are Sb, Cu, Pb, Mo, Cr. The soils and their PM10 fraction in the transport zone, where Sb, Cu, Pb, Co, V, W, Ni are accumulated, are the most polluted. The greatest influence on the chemical composition of urban soils and PM10 particles is exerted by emissions from railway infrastructure and coal combustion at the Central Thermal Power Plant (22% for soils in general and 48% for the PM10 fraction). The average total level of contamination of urban soils and PM10 fraction corresponds to a low, non-hazardous level (Zc=6). The total non-carcinogenic risk of soil particles contaminated with heavy metals and metalloids. entering the body of children, exceeded the safe level 1 (from 1.60 in a residential one-story zone to 1.81 in a transport zone). For the adult population, HI values were below the acceptable threshold value. For adult health, there is no carcinogenic risk associated with ingestion or skin contact of As, Cr and Pb. For children, a dangerous risk (ILCRingest 5.56*10–4) of ingestion of carcinogenic heavy metals and metalloids was identified.

The pollution of the topsoils of the city of Gusinoozersk (Republic of Buryatia) under the influence of emissions from State District Power Plant (SDPP) which used the Okino-Klyuchevskiy brown coal as fuel was studied. The content of 14 elements (Sr, As, Co, Mo, Sb, V, Cu, Ni, Cr, W, Zn, Bi, Cd, Pb) in bulk samples, as well as in the fraction of physical clay (particles with a diameter 10 µm, PM10) and in samples of brown coal and ash from the SDPP. Strontium, As, Co, Mo, Sb, V are the priority pollutants in the soils of Gusinoozersk with higher concentrations of most elements in the PM10 fraction. Soils and the PM10 fraction in the industrial operating subzone are the most polluted with Sr, As, Co, V, Cu, Mo, Ni, Cr, which are contained in the fly ash of the Gusinoozerskaya SDPP. Most of the territory (57% for soils in general and 47% for the PM10 fraction) is characterized by a low level of pollution (Zc = 8–16). Arsenic poses the greatest environmental hazard; in the PM10 fraction, its concentrations exceeded the MPC in 90% of the studied samples. In soils and their PM10 fraction, the leading factors for the accumulation of elements are the content of Fe2O3, organic matter, soil texture, alkaline-acid conditions, and belonging to a functional zone, which determine the formation of various classes of geochemical barriers. The polluting effect of brown coals depends on the content of heavy metals and metalloids in them. Comparison of the chemical composition of the Okino-Klyuchevskii brown coal and ash from the Gusinoozerskaya SDPP and the Kansk-Achinskii coal and ash from the Central Thermal Power Plant of Severobaikalsk showed that the brown coal and ash from Severobaikalsk were slightly enriched in metals and metalloids, which significantly reduced their accumulation in soils.

The distributions of potentially toxic elements (PTEs) among PM1, PM1–10, PM10–50, and PM50–1000 fractions of the road dust were studied in the western and eastern parts of Moscow, impacted mainly by the road transport and the industrial sector, respectively. The partitioning of PTEs in road dust can provide more precise information on pollution sources and its further interpretation regarding human health risks. The concentrations of PTEs were analyzed by mass and atomic emission inductively coupled plasma spectrometry. Differences in the results between the western and eastern parts of the city were caused by the dissimilarity between traffic and industrial emissions. The source apportionment of the PTEs was carried out using absolute principal component analysis with multiple linear regressions (PCA/APCS-MLR). The contribution from anthropogenic sources was significant to PM1 and PM1–10 particles. In coarser fractions (PM10–50, PM50–1000), it decreased due to the input with the wind-induced resuspension of soil and rock particles. In the eastern part of the city, the accumulation of PTEs (especially Mo, Sb, Cd, Sn, Bi, Co, and As) is the most active in PM1–10, while in the western part, it is most pronounced in PM1 (especially Pb, Cu, Cr, and W) which is associated with differences in the size of particles coming from traffic and industrial sources. In the eastern part of Moscow, in comparison with the western part, the contribution from industrial sources to the accumulation of PTEs in all particle size fractions was higher by 10–30

Research on air pollution in large cities by polycyclic aromatic hydrocarbons (PAHs) is one of the priority tasks for assessing air quality and environmental risks to public health. The chemical composition of aerosols sampled in spring (2018), fall (2019), and winter (2019–2020) at the Aerosol Complex of Moscow State University, located on the urban background territory of the Moscow Megacity, is analyzed. Sixteen priority PAH compounds were identified using gas chromatography, mass spectrometry, and high-performance liquid chromatography. The median value of the total concentration of the 16 PAHs (Σ16PAH) increases from the spring season (1.43 ng/m3) to the fall season (1.68 ng/m3) and then to the winter season (2.47 ng/m3). Based on the diagnostic relationships of PAHs, the dominant contribution of transport, industrial enterprises, and the heating system to the total emissions was determined. Pollution roses indicate the location of sources of maximum concentrations of low-, medium-, and high-molecular PAHs. Pollution episodes are distinguished: in the spring of 2018 under the influence of the transport of smoke plumes of agricultural fires and in the fall of 2019 as a result of petrogenic emissions and an increase in biomass burning in the residential sector around Moscow. In the winter and fall seasons, the highest values of carcinogenic (0.45 and 0.42) and mutagenic (0.58 and 0.55) equivalents for benzo(a)pyrene were recorded in comparison with the spring season (0.26 and 0.38). The lifetime risk of developing lung cancer, calculated from the data for three seasons, is 0.5 cases per one million people.

Changes in the concentrations of PM10-bound potentially toxic elements (PTEs) during the COVID-19 lockdown period and after the revocation of restrictions were analyzed using the data received at the Aerosol Complex of Moscow State University in April-July 2020. During the lockdown, the input of biomass combustion products enriched in PTEs from the Moscow region hindered the decrease in pollutant concentrations. After the introduction of the self-isolation regime, lower concentrations of most PTEs occurred due to the decrease in anthropogenic activity and the rainy meteorological conditions. After the revocation of restrictive measures, the PTE concentrations began to increase. Multivariate statistical analysis (APCA-MLR) identified the main sources of atmospheric pollutants as urban dust, non-exhaust traffic emissions, and combustion and exhaust traffic emissions. PM10 particles were significantly enriched with Sb, Cd, Sn, Bi, S, Pb, Cu, Mo, and Zn. The total non-carcinogenic and carcinogenic risks, calculated according to the U.S. EPA model, decreased by 24% and 23% during the lockdown; after the removal of restrictions, they increased by 61% and 72%, respectively. The study provides insight into the PTE concentrations and their main sources at different levels of anthropogenic impact.

A methodological framework for a system of ecological and geochemical monitoring of urban landscapes has been developed based on a joint analysis of the chemical composition of microparticles in transit (atmospheric aerosol and precipitation, river water and suspended sediments) and depositing (road dust, snow and soil covers, bottom sediments) environments. For automated monitoring on the territory of the Lomonosov Moscow State University Meteorological Observatory, the Aerosol Complex has been created, and seasonal variations in mass concentrations of PM10, black carbon, metals, metalloids, and polycyclic aromatic hydrocarbons in atmospheric aerosol and precipitation in the Moscow megacity has been analyzed. In the aerosol-precipitation subsystem, a high washout capacity of precipitation with respect to Pb, Sb, As, Ni, Mg, K, Al, and S in the aerosols has been revealed. The enrichment of PM10 with metals and metalloids decreases in the snow-road dust-soil series, and Sb, W, Bi, Sn, Cd, Cu, Pb, Mo, and Zn are accumulated in PM10 in all three environments. The particles of PM10 suspended matter and of the Moskva River bottom sediments play a key role in transport and accumulation of Pb, Cu, Ni, and V.

The relevance of the study is caused by a significant amount of toxic emissions from thermal power plants (TPPs) operating on brown coal, which can precipitate from the atmosphere and accumulate in urban soils. To assess the impact of TPP emissions on soil pollution in the city of Gusinoozyorsk (Republic of Buryatia), samples were taken from the upper (0-10 cm) horizons on a regular grid. With the help of the ICP-MS and ICP-AES methods the content of Zn, As, Cd, Bi, Pb, Cr, Co, Ni, Cu, Sb, Mo, V, W, Sr, Ag were analyzed in 79 soil samples, as well as in brown coal and ash of Gusinoozyorsk TPP, whose emissions are the main source of pollution. Brown coals contain concentrations of Mo, W, Sr, Zn, V 1.5-2.9 times higher than the clarkes for coals of the world. Ash is enriched with Mo, Sr, V, Cu, Co compared to world clarkes. The ability of soils to adsorb heavy metals, arsenic and antimony is determined by their physicochemi-cal properties: a slightly alkaline reaction, a medium loamy texture and an average content of organic matter (2.7%). The soils of the industrial operating and one-storey residential land use subzones are the most contaminated. In the first zone Cu, Ag, As, Sr, Co, V, Ni, Sb accumulate which are associated with emissions from the Gusinoozyorsk TPP and the influence of coal dust. In the second zone Sb, Cu, Sr, Zn, Ag, Cd, Pb accumulate which enter the soils with fly ash from the TPP, household waste and car emissions. Heavy metals and metalloids in the soil cover have formed several local anthropogenic anomalies of high and moderate contrast, which occupy 7% of the city's area.

Enterprises of fuel and energy complex are the main sources of carcinogenic and mutagenic potentially toxic elements (PTEs). Their particulate and gaseous emissions, wastes, and effluents enforce migration processes of PTEs in atmosphere, soil, and then in water bodies, creating a danger to the functioning of aquatic ecosystems. Vulnerable objects include water bodies with slow water exchange, due to the accumulation of PTEs in the bottom sediments and the threat of secondary contamination. Among them it is necessary to note cooling ponds of thermal power plants (TPP). In this study, the ecological and geochemical state of components of “water-suspended sediments-bottom sediments” aquatic system is assessed on the example of the Gusinoye Lake (the Republic of Buryatia), which is used as cooling pond for the largest in the region TPP, burning brown coal from local deposits. The Gusinoye Lake is the second largest lake in Buryatia after the Baikal Lake and a valuable source of water supply, place of recreation, and fish breeding. To study the distribution of PTEs in the waters of the lake, a network of 19 monitoring stations was deployed in the summer of 2019. In contrast to the previous researches, detailed studies of the central deep-water part of the lake were carried out. As a result, data on the concentration of PTEs in the dissolved and suspended forms and also in bottom sediments was obtained. To study the balance of chemicals in the lake, its main tributaries were surveyed, as well as the drainage channel of TPP. For the first time, for the Lake Gusinoye, bulk concentrations of As, Cd, Pb, Zn, Co, Mo, Cu, Sb, Cr, V, Mn, Sr, and Ag were determined using the inductively coupled plasma mass spectrometry. The highest concentrations of dissolved PTEs in the lake water are confined to the mouths of tributaries in the northern part of the lake. Dissolved Sr, Mo, and Cu in the lake exceed maximum permissible concentrations (MPCs) for fishery. The maximum concentrations of Sr and Cu are almost 3 MPCs and that of Mo is 22 MPCs near the TPP. The suspended sediments of the Gusinoye Lake are depleted of all studied PTEs as compared to the regional clarkes (natural abundances) of the lithosphere. Mn has the highest concentrations in the suspension, and its maximum concentration was due to the surface runoff from the solid waste landfill and an abandoned coal mine. Concentrations of Cu, Zn, Sr, Mo, and Pb in bottom sediments are higher than in suspended sediments, thus indicating the accumulation of pollutants. The maximum intensity of accumulation is characteristic of the deep central basin of the lake and its eastern part, where Sr, Ag, and Mo accumulate most intensively near the coal field. The main sources of PTE pollution are concentrated in the northern and northeastern parts of the lake catchment area. Significant amount of dissolved Mo, Sr, and As enter the lake with the waters of quarries and mines of the coal fields, the solid waste landfill of the town of Gusinoozyorsk, and northern rivers-tributaries, draining the dumps of the large Zagustaj coal field.

Environmental geochemical studies of urban territories involve heterogeneous information that can be most effectively processed within a unified database (DB). Since a significant portion of the accumulated data is georeferenced, geographic information technologies should be used at all stages of the researches. The purpose of this work is to consider the structure of the DB for information support of ecological and geochemical studies of different urban environments in Moscow within the framework of the Russian Science Foundation project No. 19-77-30004 "Integrated technology for environmental assessment of Moscow megacity based on chemical analysis of microparticle composition in the "atmosphere - snow - road dust - soil - surface water" system (Megacity)". The project aims to develop technologies for the chemical analysis of the urban environments impacted by the pollutants coming from vehicles, industry, and construction sites, as well as the assessment of the environmental state of the megacity. Various components of the environment are analyzed at several spatial scales: for the entire Moscow city, for administrative districts, for drainage basins of two urban rivers (Moskva and its tributary Setun). The composition of pollutant emissions is characterized using monitoring aerosol data at the Meteorological Observatory of Lomonosov Moscow State University. Microparticles PM10 and PM2.5 are analyzed for the content of elemental carbon, ionic and organic compounds, as well as potentially toxic elements, under different meteorological conditions and seasonal variations. The fallout of aerosols during winter is determined by the chemical analysis of dissolved and solid fractions of snow samples and its comparison with a natural background. Water migration of pollutants is assessed by analyzing river flows (water and suspended/bottom sediments) at reference stations in the Moskva River basin. The ecological state of road dust and soils that accumulate pollutants is estimated in geochemical surveying. Finally, source apportionment is quantified using statistical methods of multivariate analysis. The development of a DB with the integrated geographic information system (GIS) allows systematizing the spatial and non-spatial information accumulated in field works, chemical and analytical studies, and organizing effective data storage and processing along with providing geoinformation support for DB users. We created four DB subsystems designed for: (1) processing georeferenced data (GIS); (2) working with time series; (3) handling regulatory and reference information; (4) assessing pollution and environmental hazard with computational models. For Moscow megacity, GIS brings together two large blocks of information: spatial layers stored within the geodatabase and spreadsheets with the results of field studies and chemical analyses. The main functions of the GIS are geoprocessing, execution of non-spatial and spatial queries, data analysis (including exploratory spatial data analysis and modeling), visualization of the results. The report will present subsystems of the DB and the interrelationships between them. The use of the database in practice will be considered on the example of assessing the pollution of road dust with benzo(a)pyrene, accounting for anthropogenic and natural factors.