Long-term cyclicity of trace element in the Baikal aquatic ecosystem (Russia).

Longitudinal monitoring studies (between 2006 and 2019) of the chemical composition of the water from the Angara River source (the runoff of Lake Baikal) revealed the interannual, year-round and monthly cyclicity in the distribution of some trace elements vis-à-vis their concentrations. The change in the concentrations of elements was contingent on the season, the temperature of the air and water, the activity of phyto- and zooplankton and regional changes in the environment (floods, earthquakes, fires, tourism, ships, technogenesis etc.).

The cyclicity in the changes in the chemical composition of the water source of the Angara River (Baikal Stock) in 2017-2018 in comparison with the last 20 years of data.

The relevance of the research is due to the increasing need for drinking water in the world, the shortage of which is experienced in many countries. The main aim is the study of the chemical composition of freshwater of the Angara River (the drain of Lake Baikal) and the characteristics of its changes. Methods of research: water was sampled at a distance of 1.