ИСТИНА

The process of airborne dust deposition connects soils with the atmosphere and other components of the city environment. Solid atmospheric fallouts are usually mentioned in the context of pollution assessments. However, such fallouts from the atmosphere actually include very diverse solid components that are deposited on the surface of soils. The air dust (solid atmospheric fallouts) that fell out of atmosphere was collected at several sites of the South-West of Moscow city (Russia). There were different in the type of anthropogenic impact (traffic, public, recreational areas). The microscopy studies and microanalysis were carried out in order to characterize the composition of the organic part of urban solid atmospheric fallouts and its possible impact on soils and the urban ecosystem as a whole. To identify the origin of dusty microfragments, the shapes and composition of samples of different materials were considered. The studied dust samples were generally similar in their composition, with abundant quantities of silicate grains and microscopic particles of building materials, especially in samples taken near buildings. Dust aggregates with salt cementation, microplastics, textile fibres, fungal hyphae were common in samples from different study sites. Roadside dust deposits also included asphalt particles, microfragments of car tires and thin films of hydrocarbons. Dust deposits within recreational zones were enriched in organic residues, pollene graines and aeroplankton species. Atmospheric dust aerosols contain particles enriched in phosphorus and other biophillous elements because of faecal contamination. A high diversity of isolated Enterobacteriaceae including the opportunistic and potentially pathogenic species confirmed the presence of faeces. This research was performed according to the Development program of the Interdisciplinary Scientific and Educational School of M.V.Lomonosov Moscow State University «The future of the planet and global environmental change» and supported by Russian Foundation for Basic Research, Project no.19-05-50093 (oject 19-05-50093: samples collection, determination of soil properties and their interpretation), State task no. 0148-2019-0006: the microscopy studies and microanalysis).