Snow-dirt sludge as an indicator of environmental and sedimentation processes in the urban environment.

The formation of snow-dirt sludge (SDS) via the mixing of snow and surface-deposited sediment by vehicles and pedestrians is one of the least studied sedimentation processes in urban areas. The aim of this study was to analyse the material, mineral, particle size, and chemical compositions of the SDS solid phase. The study was conducted using Ekaterinburg, Russia, as an example city with an intense anthropogenic impact and a long cold snowy period. The average content of the SDS solid phase was approximately 35 g L of meltwater on heavy traffic roads, of which the dust fraction (<0.1 mm) accounted for 23 g L. On driveways and lawns, the contents of the SDS solid phase were 12 and 6.6 g L, respectively. The mineral composition of the SDS solid phase was generally similar to the geology of the surrounding area, which is composed of a mosaicked combination of felsic and mafic complexes. The presence of building material fragments and other anthropogenic particles confirms the significant anthropogenic impact. The chemical composition contained major and minor elements specific to the minerals and materials that constitute the SDS solid phase. There was significant variability in the concentrations of Pb, Cu, and Zn in the granulometric fractions, indicating pollution. Intensive melting of SDS with a high particulate matter (PM) content is an important factor influencing the environmental quality of the urban environment.