This paper is the first assessment of the balance of biogenic elements and organic carbon, the main components of the trophic state of the Lake Baikal ecosystem. Based on long-term studies (2011–2020), we calculated the influxes of different forms of phosphorus, nitrogen, silica, and organic carbon via rivers, precipitation, gaseous impurities, and aerosols in the lake. Studies between 2011 and 2020 were carried out during a period of low river water level (2011–2017) and a period of increasing river flow to a level equal to long-term averages (2018–2020), revealing patterns in the influx of these elements into the lake with the river runoff during different water levels. Tributaries are the main suppliers of elements to the lake, although atmospheric deposition of mineral forms of nitrogen and phosphorus has increased in recent years to 56% and 58%, respectively, of their total annual input at the end of the past century. For the first time, organic forms of phosphorus and nitrogen were taken into account in chemical balance calculations. These external inputs were compared with their internal load in Lake Baikal waters and outflow from the lake with the Angara River. Statistical analysis revealed that the range of intra- and interannual fluctuations in the concentrations of nitrogen and phosphorus in the water column of the lake remains unchanged. Mass balances for biogenic elements and organic carbon demonstrate that in the modern period, as previously, most of the elements remain in the lake.

The aim of this study was to reveal factors causing the differences in the distribution and origin of polycyclic aromatic hydrocarbons (PAHs) among air, water, soil and sediments. The concentrations of twelve priority PAHs in samples were measured. It was observed that PAH concentrations in all ecosystem compartments increased with a decrease in distance from settlements. PAH concentrations also increased with an age of PAHs. It was proved that unlike air and water the ratio between gas phase and particle phase PAHs in bottom sediments and soils does not change over time. It was found that due to PAH partitioning among ecosystem compartments, the hydrophobic particle phase PAHs were fixed in soils and bottom sediments, whereas water-soluble particle/gas phase PAHs were leached from soil to rivers and lakes. It was also found that the precision of PAH source identification using the diagnostic ratio (DR) approach depends on the similarity of physicochemical properties of diagnostic PAHs and on their affinity to the predominant phase of the studied ecosystem compartment. The inconsistency between contributions of DR-derived and real PAH sources to the pollution of environmental compartments is probably conditioned by the inconsistence between literature-derived DRs and DRs characteristic for local sources.

The Baikal region, including areas with poor environmental conditions, has significant clean background zones. In the summer of 2023, we analyzed the physical and chemical parameters of aerosol particles with different size fractions at Irkutsk and Listvyanka monitoring stations. Reduced wildfires and minimal impact from fuel and energy industries allowed us to observe regional and transboundary pollution transport. A large data array indicated that, during the shift of cyclones from Mongolia to the south of the Baikal region, the concentrations of Na+, Ca2+, Mg2+, K+, and Cl− ions increased at the Irkutsk station, dominated by NH4+ and SO42−. The growth of the ionic concentrations at the Listvyanka station was observed in aerosol particles during the northwesterly transport. When air masses arrived from the southerly direction, the atmosphere was the cleanest. The analysis of 27 elements in aerosols revealed that Al, Fe, Mn, Cu, and Zn made the greatest contribution to air pollution at the Irkutsk station, while Fe, Al, Cu, Cr, Mn, and Ni made the greatest contribution to air pollution at the Listvyanka station. The dynamics of the investigated elements were mainly due to natural processes in the air under various synoptic situations and weather conditions in the region, although anthropogenic factors also affected the formation of aerosol composition wth certain directions of air mass transport.

A statistical summary of chemical composition of atmospheric aerosol is presented based on the long-term research results obtained in the Eurasian sector of the Arctic Ocean: concentrations of 8 ions, 22 trace elements, organic and elemental carbon (OC, EC), as well as total carbon isotopic composition δ13C. The average aerosol characteristics were obtained: 5.14 μg/m3 for the total ion concentration with a predominant contribution (72

In recent years, the role of the atmosphere in the formation of the chemical composition of water in Lake Baikal and its tributaries has been increasing. In this regard, the study of equivalent black carbon (eBC) in the air above the lake and its coast has an important practical application. This paper presents the results of the mass concentration of eBC and submicron aerosol in the air above the water area of Lake Baikal, which were obtained during expeditions onboard research vessels in the summer of 2019 and 2023. We analyzed the data from the coastal monitoring station Listvyanka. To measure eBC, an MDA-02 aethalometer was used in the water area of the lake, and a BAC-10 aethalometer at the Listvyanka station. The background level of the eBC concentration in the air at different areas of the lake ranged between 0.15 and 0.3 µg m−3. The results of the two expeditions revealed the influence of the coastal settlements and the air mass transport along the valleys of the lake’s large tributaries on the five- to twentyfold growth of the eBC concentration in the near-water atmosphere. In the diurnal dynamics of eBC near settlements, we recorded high values in the evening and at night. In background areas, the diurnal dynamics were poorly manifested. In the summer of 2019, there were smoke plumes in the water area of Lake Baikal from distant wildfires and a local fire site on the east coast of the lake. The eBC concentration increased to 5–6 µg m−3, which was 10 to 40 times higher than the background. The long-range transport of plumes from coal-fired thermal power plants in large cities of the region made the major contribution to the eBC concentration at «Listvyanka» in winter, which data on aerosol, gas impurities, and meteorological parameters confirmed.

Since 2017 we have carried out aerosol sampling at the research station “Ice Base Baranova Cape” (Novaya Zemlya Archipelago) with the purpose of studying the variations in aerosol physicochemical characteristics: the concentrations of ions, microelements, organic and elemental carbon (ОС and ЕС), as well as the isotopic composition of carbon δ13C in the aerosol. The average summed concentrations of ions throughout the period of measurements were 1,99 μg/m3, the concentrations of elements were 51,1 ng/m3; and those of ОС and ЕС were 398 and 25 ng/m3, respectively; the isotopic composition of carbon δ13C was–27.6 ‰. The main contribution (73 %) to the ion composition of atmospheric aerosol is due to “marine” ions Na+ and Cl-, and the contribution to the elemental composition is due to terrogenic Fe and Al (71 %). The large enrichment coefficients (with respect to Na+ in sea water) were manifested for ions SO 2-, K+, and Ca2+. Aerosol enrichment by these ions is the largest in the warm period. In the aerosol elemental composition, we identified large enrichment coefficients (with respect to Al in the Earth’s crust) in elements Se, Sn, Sb, Mo, As, Zn, Cu, Cr, Pb, and Cd, indicating their technogenic origin. The nearest sources of aerosol enrichment by technogenic elements are plants for mining and processing mineral resources in the Taymyr Autonomous Okrug. The statistical generalization of the multiyear data allowed us to calculate for the first time the annual average behavior of the chemical composition of aerosol in the study region. With respect to the seasonal variations, the ions and elements can be divided into three groups: 1) with winter maximum (Na+, Cl-, Mg2+, Br-; Se, Cd, V, Co, As); 2) with summer (PO 3-, NH +, CH SO3-, F-) or autumn (Al, Ti, Li, Sr, Fe, Zn, Ba, Ni) maximum; 3) with poorly defined or indefinite variations in other ions (NO -, K+, SO 2-, Ca2+) and elements (Cu, Pb, Mo, W, Sn, Cr, Sb, Mn). As most of the other characteristics, the annual behaviors of the ОС and ЕС concentrations are characterized by the general maximum in the winter-spring period. In addition, a second maximum is manifested in the ОС content in the summer-autumn period. The average monthly carbon isotopic composition in the aerosol varies in the range from –28.3 ‰ (February) to –27.3 ‰ (May).

В обсерватории «Фоновая» с осени 2021 года установлен 13-каскадный импактор высокого разрешения 125R NanoMoudi-II, способный селективно отбирать аэрозоль разного диапазона дисперсности с номинальными размерами: 10000, 5600, 3200, 1800, 1000, 560, 320, 180, 100, 56, 32, 18 и 10 нм. Кварцевые и тефлоновые фильтры используются для исследования ионно-элементного и органического состава фракций приземного фонового аэрозоля, соответственно. Анализ кварцевых фильтров производится в Иркутском лимнологическом институте СО РАН методами ионной хроматографии и ИСП-МС. Тефлоновые фильтры типа Grimm 1.113A используются для отбора и анализа органических аэрозолей методом ГХ-МС в ИХКГ СО РАН. Обсуждается химический состав отобранных в 2022 году проб продолжительностью от 6 до 16 суток, состав которых анализируется опробированными в 2021 г. методиками. Изменчивость содержания ионной компоненты аэрозоля в течение года достигает порядка величины, с максимумом в конце зимы и минимумом летом. «Зимний» пик основы ионной фракции - сульфат-аниона - лежит в области 0,56-1 мкм, смещаясь летом в область более мелких частиц 0,18-0,32 мкм. Для микроэлементов как временной ход концентраций, так и распределения по размерам имеют более сложный вид. A high-resolution 125R NanoMoudi-II impactor with 13 cascades has been installed at the "Fonovaya" Observatory since the autumn of 2021. It is capable of selectively sampling aerosols of varying size ranges with nominal sizes of 10000, 5600, 3200, 1800, 1000, 560, 320, 180, 100, 56, 32, 18, and 10 nm. Quartz and Teflon filters are used for studying the ionic-elemental and organic composition of ground-level background aerosol fractions, respectively. The analysis of the quartz filters is carried out at the Irkutsk Limnological Institute of the Siberian Branch of the Russian Academy of Sciences using ion chromatography and ICP-MS methods. Teflon filters of type Grimm 1.113A are utilized for sampling and analyzing organic aerosols using GC-MS in the Institute of Chemical Kinetics and Combustion of the Siberian Branch of the Russian Academy of Sciences. The chemical composition of samples collected in 2022 with exposure times ranging from 6 to 16 days is discussed, analyzed using methods tested in 2021. The variability of the ionic component of aerosol content throughout the year reaches significant levels, peaking in late winter and hitting a minimum in summer. The winter peak of the ionic fraction’s base—the sulfate anion—lies within the range of 0.56-1 µm, shifting to smaller particles of 0.18-0.32 µm in summer. For trace elements, both the temporal course of concentrations and the size distribution exhibit a more complex pattern. «Background» observatory, high-resolution impactor, ground-level background aerosol, ionic component of aerosol

На основе данных отбора аэрозольных проб на полярной станции «Мыс Баранова» (октябрь 2017 – февраль 2023 гг.) обсуждаются особенности сезонного изменения ионного и элементного состава атмосферного аэрозоля. Приводятся статистические характеристики концентраций ионов и микроэлементов для периодов максимальных и минимальных значений. Based on the data from aerosol sampling at the polar station "Cape Baranova" (October 2017 - February 2023), the features of seasonal changes in the ionic and elemental composition of atmospheric aerosol are discussed. Statistical characteristics of ion and trace element concentrations for periods of maximum and minimum values are presented.

The chemical composition of atmospheric aerosol sampled at the Cape Baranov Ice Base research station (Severnaya Zemlya archipelago) in 2017–2022 is studied. The interannual and seasonal dynamics of ions and trace elements in the aerosol composition is analyzed in detail. A 1.5-fold increase in the annual mean total ion concentrations is traced. The growth of the sum of ions was mainly due to the concentrations of Na+ and Cl− ions of marine origin, the content of which is minimal in summer and maximal in winter. The variations in the concentrations of nonmarine ions NH_4^ + , K+, Ca2+, F–, NO_2^ - , and NO_3^ - differed from the seasonal course of Na+ and Cl− concentrations: the former decreased during the transition from winter to spring and increases in summer with a subsequent decrease in autumn against the background of an increase in the sum of ions due the marine ions. The ion composition of aerosols is formed under the effect of the marine factor, air mass transport, underlying surface, and wildfires. Among trace elements, Fe, Al, Zn, Mn, Sn, Cr, and Cu dominated with high concentrations in the fall and winter periods. Based on enrichment factors, elements of terrigenous (Al, Ti, Mn, Fe, Th, and U), mixed terrigenous and nonterrigenous (Li, Be, V, Co, Sr, and Ba), and nonterrigenous origin (Ni, Cu, Zn, Cr, Mo, Mo, W, Ag, Tl, Pb, As, Se, Cd, Sn, and Sb) are identified. The highest contribution to the total level of air pollution is made by Fe and Mn in winter and autumn and by Fe and Be in spring and summer. Among nonterrigenic elements, Cu, Sn, Zn, Se, and Ni contributed the most in all seasons. The level of air pollution with trace elements is assessed as low at the Cape Baranov Ice Base station.

В докладе представлено статистическое обобщение данных многолетних измерений, которое позволило определить закономерности среднего пространственного распределения и сезонной изменчивости характеристик аэрозоля: концентраций аэрозоля и черного углерода, ионов и микроэлементов, аэрозольной оптической толщи атмосферы, а также изотопного состава углерода в аэрозоле. The report presents a statistical generalization of long-term measurement data, which allowed us to determine the patterns of the average spatial distribution and seasonal variability of aerosol characteristics: aerosol and black carbon concentrations, ions and trace elements, aerosol optical thickness of the atmosphere, as well as the isotopic composition of carbon in the aerosol.

На основе данных 14-и экспедиций, обобщаются результаты измерений ионного и элементного состава аэрозоля в приводном слое атмосферы Евразийского сектора Северного Ледовитого океана (от Гренландского моря до Чукотского моря). Приводятся статистические характеристики концентраций ионов, микроэлементов, а также коэффициентов их обогащения для отдельных арктических морей. Полученные характеристики сравниваются с данными многолетних измерений в субарктическом Белом море. Based on the data of 14 expeditions, the results of measurements of the ionic and elemental composition of aerosol in the driving layer of the atmosphere of the Eurasian sector of the Arctic Ocean (from the Greenland Sea to the Chukchi Sea) are summarized. Statistical characteristics of the concentrations of ions, trace elements, as well as their enrichment coefficients for individual Arctic seas are given. The obtained characteristics are compared with the data of long-term measurements in the Subarctic White Sea.

This work presents the analysis of the spatial distribution of number concentration, size distribution, and chemical composition of aerosol particles measured for the first time over the seas of the Russian Arctic. Various types of vertical distribution of the number concentration were recorded, characteristic of both coastal marine and continental areas. Most of them turned out to be of the continental type. Attention is also drawn to the almost complete absence of coarse particles above 2–3 km over all seas. The chemical composition of the Arctic aerosol at altitudes of both 200 m and 5000 m contains ions that can be referred to as both marine and continental. The identifiable carbon- and salt-free elemental part of the aerosol over the Arctic is 3–4 times larger than that of ions. Over all seas and at both altitudes, the Arctic aerosols mainly contain elements of terrigenous origin – Al, Cu, Fe, and Si. Over almost all seas, except the Barents Sea, Si is dominant in the elemental composition of the aerosol, its contribution over the Chukchi Sea reaching 85

Цель исследования заключалась в выявлении различий между составами полициклических ароматических углеводородов (ПАУ) атмосферы, воды, почвы и донных отложений водоемов и водотоков бассейна озера Байкал. Концентрации 10 приоритетных ПАУ в пробах были измерены с использованием газовой хроматографии с масс-спектрометрическим детектированием. Концентрация ПАУ во всех объектах среды значительно варьировали. Установлено, что суммарные концентрации ПАУ увеличивались с увеличением плотности вещества объекта среды в ряду атмосфера - поверхностные воды - донные осадки - почвы. Также установлено, что нелетучие гидрофобные ПАУ, состоящие из 5-6 бензольных колец, накапливаются в почвах и донных отложениях, тогда как растворимые в воде летучие ПАУ, состоящие из 3-4 бензольных колец, накапливаются в поверхностных водах.

Results are presented from a statistical generalization of data on the microphysical characteristics and ion composition of aerosols in the atmosphere of the White Sea obtained during the 2003–2021 expeditions. Based on the recalculation of the measurement results using a homogeneous data filtering algorithm, we consider the total number concentration of particles with radii of 0.2–5 μm, the volumes of fine and coarse near-water aerosol particles (smaller and larger than 0.5 μm in radius), and the volume particle distribution function. We estimate the mass concentrations of eight water-soluble ions in aerosol composition (Сa2+, Mg2+, Na+, K+, $${\text{NH}}_{4}^{ + },$$ $${\text{NO}}_{3}^{ - },$$ Cl–, and $${\text{SO}}_{4}^{{2 - }})$$ . The spatial nonuniformities and causes for anomalously high concentrations and ion composition of the aerosols are analyzed.

The results of studying the chemical composition of atmospheric aerosol, precipitation, and snow cover on the territory of the Baikal State Biospherical Nature Reserve during 2017-2021 are presented. The principal ions in atmospheric aerosol and precipitation were sulfates and ammonium and those for snow cover were sulfates, nitrates, and calcium. The series of detailed simulations with the HYSPLIT model and the methods for statistical data processing (ArcGIS 10.2 and RStudio software) enable the identification of natural and anthropogenic groups of sources affecting the chemical compound of atmospheric deposition on the eastern coast of Lake Baikal. Based on snow survey data, the accumulation of the substances, which are the indicators of anthropogenic load, in the snow cover of the Baikal State Biospherical Nature Reserve was evaluated.

This paper presents the results of chemical composition analysis of aerosol samples taken in the summer of 1998–2001 and 2013–2021 at the southeast coast of Lake Baikal. It was revealed that the dominant aerosol ions are SO42−, NO3−, Cl−, Ca2+, Na+. In fire periods, an increase in the proportion of nitrate ions, chloride ions, calcium ions, sulfate ions, bromide ions in suspended particles on average up to 10 times or more compared to background conditions, as well as the proportion of metal ions (calcium, potassium, sodium). The found high correlation between potassium ions and chloride ions (r = 0.8–0.9) indicates the predominant proportion of potassium chloride in the composition of atmospheric aerosols at Baikal. In case of smoke emission from the centers of intense wildfires, the proportion of secondary components in the long-range transport of smoke aerosol as a result of its aging was higher than in a regional wildfire (51.6

The spatiotemporal distribution of concentrations of trace gases (SO2, NO _x , and CO) in the atmospheric surface layer over different areas of the Baikal natural territory is analyzed using the data from seven continuous monitoring stations for 2019–2021. The most contaminated area is the zone of atmospheric influence in the western and northwestern directions from the lake (the cities of Irkutsk, Angarsk, Usol’e-Sibirskoe, Cheremkhovo). The purest area is the central zone of the Baikal natural territory. Changes in atmospheric concentrations of pollutants due to wildfires and measures taken during the COVID-19 pandemic are shown.

The differences and similarity of the chemical composition (ions, trace elements, and polyaromatic hydrocarbons (PAHs)) of the near-water atmospheric aerosol collected in summer 2021 along the expedition routes of the R/V Akademik Mstislav Keldysh in the region of the Kara Sea (the second stage of cruise 83, from June 18 to July 8, 2021), in the Barents Sea, and in the Norwegian-Greenland Basin (cruise 84, from July 24 to August 26) are revealed.

The results of studying the chemical composition of atmospheric aerosol, precipitation, and snow cover on the territory of the Baikal State Biospherical Nature Reserve during 2017–2021 are presented. The principal ions in atmospheric aerosol and precipitation were sulfates and ammonium and those for snow cover were sulfates, nitrates, and calcium. The series of detailed simulations with the HYSPLIT model and the methods for statistical data processing (ArcGIS 10.2 and RStudio software) enable the identification of natural and anthropogenic groups of sources affecting the chemical compound of atmospheric deposition on the eastern coast of Lake Baikal. Based on snow survey data, the accumulation of the substances, which are the indicators of anthropogenic load, in the snow cover of the Baikal State Biospherical Nature Reserve was evaluated.

Introduction: The products of volcanic eruptions found in the snow, firn and ice deposits of the polar ice sheets are precious sources of information on the volcanic forcing of the climate system in the recent or remote past. On the other hand, the layers containing the traces of well-known eruptions serve as absolute age markers that help to construct the depth-age scale for the snow-firn thickness. Methods: In this study we present new records of the sulfate concentrations and electrical conductivity (ECM) from three shallow (up to 70 m depth) firn cores drilled in the vicinity of Vostok station (central East Antarctica). Results: In the non-sea-salt sulfate and ECM profiles we were able to identify 68 peaks that can be interpreted as traces of volcanic events. Discussion: 22 of these peaks can be unambiguously attributed to well-known volcanic eruptions (including Tambora 1816 CE, Huaynaputina 1601 CE, Samalas 1258 CE, Ilopango 541 CE and others), which allowed to construct a robust depth-age scale for the cores. 37 events have their counterparts in other Antarctic cores, but cannot be associated with welldated eruptions. Finally, 9 peaks do not have analogues in the other cores, i.e., they may be traces of so far unknown volcanic events. According to the newly constructed depth-age function, the deepest studied firn layers (70.20 m) are dated by 192 BCE.