Different Dynamics of the Chemical Composition of Water in the Baikal Ecosystem (Baikal, Its Tributaries, and the Source of the Angara River)

Abstract —Multidirectional dynamics of changes in the chemical composition of the water of the only runoff of Lake Baikal, the Angara River, has been established. The cyclic-wave change in the interannual chemical composition of the Baikal water has been revealed, which indicates a long-term memory effect in the chemical time series of elements. Positive and negative temperature and chemical trends in the state of the water in the source of the Angara are observed, which are due to climate changes, the confinement of Baikal to the rift zone, and the composition of the enclosing rocks. It is shown that the current concentrations of monitored elements in the Angara source water depend also on their past concentrations but can change dramatically in the case of catastrophic environmental disturbances caused by natural and anthropogenic disasters (fires, drought, floods, earthquakes, etc.). The relationship between the elevated concentrations of uranium in the water and the seismic process in the Baikal area has been traced. The data obtained are based on the long-term (1950–2021) monitoring of the chemical composition of water in the Baikal ecosystem (Baikal, its tributaries, and Angara source).