Assessment of the level of pollution of the snow cover with chemical compounds and elements in the territory of the Shelekhov district in Eastern Siberia

Abstract

Introduction. In the zone of large industrial clusters of the Irkutsk region, pollution tracers are formed, which are characteristic of each territory. The study of the snow cover makes it possible to make an approximate assessment of the level of atmospheric air pollution in the winter period, as well as to determine the areas of dispersion of emissions. Materials and methods. In samples of melted snow, the main anions and cations characteristic of emissions from aluminum production were determined by photometric and titrimetric methods, turbidimetric, ionometric and atomic absorption analysis. A quantitative granulometric analysis of the composition of suspensions was carried out using a laser analyzer. Results. The distribution of particles according to the fractional composition in the districts of the city, differing in anthropogenic load, was studied. Submicroscopic particles up to 1 µm were found in all samples, while their share in the total number of particles was up to 2%. The proportion of particles up to 10 μm was 7-11%. The most predominant particle size is 10-50 microns, they account for 50% of suspensions in residential areas and up to 80% near the industrial area. It is shown that in the zone of influence of the transport highway, the content of sulfates, nitrates, calcium, and magnesium in the snow is increased. The content of fluorides, aluminum and beryllium in the snow cover is determined by the direction of the prevailing winds. Limitations. The limitation of the study is due to a samples located only in residential areas of the city and suburban agricultural territory for a one-year period (winter 2018-2019). In this article, we limited ourselves to the analysis of inorganic compounds only; the content of organic compounds is presented in another article. Conclusion. The study of the chemical composition of the snow cover in various functional zones of the city of Shelekhov allows us to conclude that the melt water of snow precipitation can be attributed to the hydrocarbonate-chloride calcium class with a high concentration of fluorides and nitrates. The nature of pollution of the urban environment is greatly influenced by emissions from industrial enterprises, vehicles and the economic activities of urban organizations. The overall pollution of the suburban agricultural area, despite the high frequency of wind in this direction, is significantly lower than in the residential area of the city. The prevailing winds contribute to the transfer of harmful substances over long distances, adversely affecting the ecosystems of the region.