Ecological and geochemical characteristics of the snow cover in the Yakutsk city (Central Siberia)

Abstract

For the first time, the geochemistry of snow cover on the territory of the city of Yakutsk, the largest city located in the permafrost zone, is considered on the basis of recent methods of analysis. To study the chemical composition of the snow cover and estimate the ecological state of the city in March 2020, 80 snow samples were collected on its territory and analyzed for a wide range of chemical elements. It was found that the background chemical composition of the soluble phase of the snow cover in the Yakutsk region is typical for the middle taiga landscapes of Yakutia: chloride-hydrocarbonate, predominantly calcium, with an acidic reaction and very low mineralization. On the basis of the present-day technique of analysis, the features of the transformation of the chemical composition of the soluble phase of snow cover in the urbanized area were evaluated. In the zone of technogenic action, the mineralization of snow water increases following the increase in the concentration of sulfates, calcium and ammonium; the reaction becomes alkaline. The technogenic load on the snow cover in Yakutsk and the main factors of its formation had been determined. The contribution of pollutants in the gas-aerosol phase is approximately 0.2% of the volume of winter dust fallout. In winter, the main source of pollution of the atmosphere here is the motor transport, and to a smaller degree - energy facilities and industrial enterprises. The features of the macro- and microelement composition of the soluble phase of snow were established as well. Macropollutants and nitrogen compounds account for 90–95% of the total atmospheric precipitation, the major quantity of which is carbon. The most contrasting technogenic transformation of microelements is characteristic of Cu, Fe, Cd, Sn, Zn, and Al. The value and parameters of the winter atmospheric load on the snow cover had been determined. The characteristics of the ionic composition of the soluble phase of snow in Yakutsk and the parameters of their changes had been revealed. Almost throughout the whole city, the level of contamination with toxic elements is estimated as low and moderately dangerous. Heavy metal pollution of the snow cover here is noticeably lower than this takes place in the cities of Eastern Siberia (Blagoveshchensk, Bratsk, Irkutsk, Chita).