Features of the chemical composition of water in the urban lakes of Murmansk

Abstract

The article presents the results of studies of the hydrochemical composition of five urban lakes of Murmansk. It was found that the chemical composition of the water of the studied urban lakes is significantly different from the composition of the lakes of the northeastern part of the Murmansk region of the Barents Sea catchment, which was taken as the background. The water pH values have increased in comparison with the background values, as well as mineralization, the content of major ions, nutrients, and heavy metals. An increase in the content of the main cations of alkaline and alkaline-earth metals (Ca2+, Mg2+, Na+ и K+), as well as the main anions (HCO3 –, SO4 2–, Cl–), is associated with the influence of urban environments, including the use of reagents for deicing of roads. Due to the influx of marine aerosols in the waters of urban lakes, the content of other alkaline (Li and Rb) and alkaline-earth (Sr and Ba) metals, as well as B and Br, is increased. Mineralization of water in the Murmansk lakes is ten times higher than the values recorded in the lakes of the northeastern part of the Murmansk region of the Barents Sea catchment. In the water of urban lakes, the content of compounds of the nitrogen group, especially the ammonium ion, is significantly increased, which indicates the formation of a restorative environment that has a detrimental effect on hydrobionts. Lakes Ledovoe and Yuzhnoe are the most polluted among the studied lakes, characterized by the highest content of the above-mentioned indicators, as well as many heavy metals (Ni, Cu, Zn, Co, As, Mo and W). At the same time, there is a decrease in the content of organic substances in the most polluted lakes due to inhibition of biological processes.