The current state of the water and bottom sediments in the Irkutsk Reservoir

Abstract

We present the results of the study on the state of the water and bottom sediments in the Irkutsk Reservoir for the period from 1976 to 2018. This reservoir is the main in the cascade of the Angara River reservoirs. It belongs to shallow artificial reservoirs with high flow. The Irkutsk Reservoir receives the basic water supply from Lake Baikal, which serves as its summit pound. We have determined that the composition of the water and bottom sediments in the reservoir depends on the elemental composition of the rock composing its eroded banks as well as on the water flowing from Lake Baikal. Based on the concentrations of the main elements, the water in the reservoir after 60 years of its operation corresponds to potable water standards. The water pollution coefficient for all elements, especially for Pb and Mn, slightly exceeded the MPC values at the sites of Nikola (Baikal water) and Solnechny (near the dam of the Irkutsk Hydroelectric Power Station). Based on the pollution coefficients, the bottom sediments are at the level of the geochemical background of the rocks composing the south of the Siberian platform. The geochemical parameters of the water and bottom sediments indicate that the Irkutsk Reservoir belongs to water bodies with the low anthropogenic pressure.