—Data on the influx and behavior of humus substances in natural waters are considered. The widest spread methods of analyzing physicochemical properties of natural polymers causing their interaction with metal ions are analyzed. The concept of metal complexation with humus substances at different chemical equilibria is developed on the basis of original and an available literature review evaluating the metal speciation in natural objects (lakes, rivers, seas).

Snowpack is a unique indicator in assessing both local and transboundary contaminants. We considered the features of the snow chemical composition of the Valday Upland, Russia, as a location without a direct influence of smelters (conditional background) in 2016–2019. We identified the influence of a number of geochemical (landscape), biological (trees of the forest zone, vegetation), and anthropogenic factors (technogenic elements—lead, nickel) on the formation of snow composition. We found increases in the content of metals of technogenic origin in city snowfall in the snowpack: cadmium, lead, and nickel in comparison with snowfall in the forest. Methods of sequential and parallel membrane filtration (in situ) were used along with ion-exchange separation to determine metal speciation (labile, unlabile, inorganic speciation with low molecular weight, connection with organic ligands) and explain their migration ability. We found that forest snow samples contain metal compounds (Cu, Pb, and Ni) with different molecular weights due to the different contributions of organic substances. According to the results of filtration, the predominant speciation of metals in the urban snow samples is suspension emission (especially more 8 mkm). The buffer abilities of snowfall in the forest (in various landscapes) and in the city of Valday were assessed. Based on statistical analysis, a significant difference in the chemical composition of snow in the forest and in the city, as well as taking into account the landscape, was shown. Snow on an open landscape on a hill is most susceptible to airborne pollution (sulfates, copper, nickel), city snow is most affected by local pollutants (turbidity, lead).

The data on the metal contents and acidification of small lakes caused by airborne contamination of the watershed in three industrial regions of the Arctic—European Russia (Kola region), Western (Yamal-Nenets region) and Eastern Siberia (Norilsk region)—have been presented for the first time. It has been proven that acidification and enrichment by metals of water connect with sulfur dioxide and metals emissions from copper–nickel smelters, contaminating the catchments, with associated gas burning during raw hydrocarbon production. To assess the effects of acid deposition, critical loads and their exceeds were calculated: exceeded by 56% and 12.5%, respectively, in lakes in the Kola region and in the north of Western Siberia; the catchments of the East Siberian region are resistant to acidification. Water enrichment factors (EF) by elements were calculated to show that the waters of the Norilsk and Kola regions are enriched with Ni, Cd, As, Sb and Se as a result of emissions from copper–nickel smelters. The oil and gas industry in the northern regions of Western Siberia lead to the increase in V, Pb and Mo concentrations in the waters. The high values of EF and excess of acidity critical loads for water are explained by the local and transboundary pollution impacts on the catchment of small lakes.

—Data on the water quality and the contents of a large group of elements in small lakes are reported for three regions of the Arctic basin: European Russia (Kola region), Western (Yamal–Nenets district) and Eastern (Norilsk region) Siberia. All studied waters are low-salinity and oligotrophic. The air pollution in the lake waters caused the elevated concentrations of many elements. The waters of the Norilsk and Kola regions are enriched in Ni, Cd, As, Sb and Se owing to the distribution of smoke emissions from copper–nickel smelters over long distances. The petroleum industry leads to increased concentrations of V, Pb, and Mo in water. The degree of anthropogenic influence on the lake waters of the Arctic regions was estimated using the Enrichment Factors (EF). The high values of EF for most part of analyzed elements are explained not only by anthropogenic dispersion of elements, but also by a change in the conditions of element migration and the geochemical features of ore occurrences. The calculations demonstrated the effect of anthropogenic dispersion on the enrichment of Arctic waters by a large group of elements, including toxic ones.

Hypotheses of humus formation on the basis of polymerization and oxidation reactions were considered. The most popular models of several authors and the general understanding of the structural features of natural polymers were analyzed. Multivariate statistical analysis was performed for zonal factors affecting the formation of humic substances. Evolutionary changes in the understanding of the biospheric functions of humus substances were evaluated. Statistical procedures were proposed for the prediction of the physicochemical behavior of humus substances in environments.

The paper discusses variations in the migration activities of elements in parent rocks of soils under the effect of anthropogenic and geochemical factors. The unique geological characteristics and the diverse mineral resources of the study area predetermined the high susceptibility of water bodies in the Kola Peninsula to influences of parent soil-forming rocks at watersheds and to anthropogenic impacts. Selected typical alkaline and acid rocks of the area were used in static and dynamic experiments on leaching elements from these rocks. The extracting agents were doubly distilled water, sulfuric acid, solutions of fulvic acids, and solutions of fulvic acids after their degradation by sulfuric acid. The results show differences in the extraction of trace elements from rocks by the various extraction agents: the water extracts are characterized by the maximum recovery of some elements in experiments with alkaline rocks (the extraction Ni and Cu was four- and threefold greater than in the other experiments), and extracts by sulfuric acids from acid rocks resulted in higher concentrations of U (twofold) and Cu (less than one order of magnitude). Fulvic acids most strongly affect all of the studied rocks. According to data of discriminant analysis, the greatest contributions (with a coefficient close to 10) to the discrimination is made by the following parameters: trace elements of the La group, heavy-metal ions (Ni, Cu, and Pb), and pH.