FORMATION OF THE COMPOSITION OF TRACE ELEMENTS OF SNOW DUST IN TYUMEN AND TOBOLSK USING HIERARCHICAL CLUSTER ANALYSIS

Link for citation: Zakharchenko A.V., Pasko O.A., Tigeev A.A. Formation of the composition of trace elements of snow dust in Tyumen and Tobolsk using hierarchical cluster analysis. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 110-120. In Rus. The relevance: search for new methodological approaches and techniques for assessing the aerosol migration of substances and characterizing air pollution. The purpose of the work is a comparative analysis of clusters of the content of microelements of the solid phase of snow in the closely located cities of Tyumen and Tobolsk with respect to clean background and areas subject to technogenic impact. The materials: the trace elements of solid phase of the snow cover. The methods: chemical-analytical for determining the content of trace elements, hierarchical cluster in the analysis of geochemical spectra, probabilistic-statistical. Results. The background dust load in Tobolsk is less, and the inner city load is higher compared to Tyumen. A cluster data structure of 8 clusters has been established with the allocation of two large groups that combine the Tobolsk and Tyumen sites, which are divided into clusters with low and high content of trace elements. Conclusions. The conditionally background cluster C6 is present in Tobolsk (22,6 %) and Tyumen (11,7 %), and C5 – 13 % in Tobolsk and 8 % in Tyumen. A specific Tobolsk cluster C8 with a predominance of scattered elements (48 %) was found at 2 sites in Tyumen, which may indicate a possible transfer of aerosols between these cities. Some technogenic clusters contained heavy metals, while others were dominated by Sc, Cr, Ni, Zn, and Cd. Technogenic clusters (C7, C1) differ in the shape of the geochemical spectrum: heavy metals predominate in some, trace elements (C8) predominate in others; the same applies to conditionally background samples. The specific technogenic Tyumen cluster C4 is distinguished by high values of Cu and Mo. Conditionally isolated background clusters had a low content of microelements. To identify environmental conditions, we moved from the standardized values of cluster analysis to their material content. It is shown that some clusters contain heavy metals, while others contain Sc, Cr, Ni, Zn, and Cd. Conditionally isolated background clusters had a low content of microelements. Using the content of microelements of the C5 cluster as a background, the environmental index of pollution Zc was calculated, which in Tobolsk reaches a high and dangerous level of pollution 60,8–83,7, in Tyumen – an average, moderately dangerous level Zc (32–64). The use of cluster analysis makes it possible to determine the trace elements pollution of snow dust and the territory as a whole.