Home – Home – Jornals – Geography and Natural Resources 2022 number 2

A wide-scale investigation providing insights into the spatial and temporal distribution of sanitary and microbiological indicators of water quality was undertaken in the shallow nearshore zone of Lake Baikal. Water samples were collected along the entire lake perimeter during several years, from 2012 to 2016, and in 2020 (total number, n = 450). Comparison of the abundance of fecal indicator bacteria in the bottom and surface waters at a total depth of 1 m showed that the concentration of sanitary indicator bacteria was generally higher in the surface water layers. The dynamics of water quality indicators as determined from May to November at the monitoring stations in the villages of Listvyanka and Bol’shie Koty did not reveal, according to statistical calculations, any substantial differences in the number of fecal indicator bacteria in most cases for different months of this study. Results of four circum-Baikal surveys at the same stations in June and September 2015 and 2016 also showed no notable differences in terms of the period of sampling. The concentration gradient of the fecal indicator bacteria 100 m from the water edge exhibited an consistent decrease of these microorganisms with distance from the shore towards deeper parts of the lake. An area of sampling was revealed, in which the concentrations of fecal indicator bacteria exceeded considerably the regulatory standards (SanPiN 2.1.5.980-00). The village of Khuzhir was such a site. In the shallow water at the villages of Sakhyurta and Kultuk, the concentrations of fecal indicator bacteria were on the verge of maximum permissible concentration. These data provided evidence of constant and significant water pollution in the nearshore zone adjacent to settlements characterized largely by touristic activities (the recreational activity is increased)