Monitoring of the snow cover chemical composition and its role in the acidification of the southern Baikal tributaries

On the basis of the hydrochemical data available for the period of 1996-2019, the changes in the chemical composition of snowmelt and river waters on the southeast coast of Lake Baikal, that were under the long-term influence of industrial emission impact, are assessed. The study shows that the closure of the Baikalsk Pulp and Paper Mill in 2013 resulted in the decrease in the concentrations of metal cations in snow cover and in their neutralization capacity. Snow water pH value decreased, and the relative composition of major ions changed as well. In the catchment area of the Khara-Murin and Pereemnaya Rivers, hydrogen became the dominant cation during snowmelt. Further reduction of river water (especially low mineralized river water) resistance to acid components is registered.