Sanitary-microbiologial assessment of the water quality in the Listvennichnyi Bay at the period of extremely high water level in Lake Baikal
G.V. PODLESNAYA, A.D. GALACHYANTS, Yu.R. SHTYKOVA, M.Yu. SUSLOVA, E.A. ZIMENS, M.M. MAKAROV, O.A. TIMOSHKIN, O.I. BELYKH
Limnological Institute, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
Keywords: coliform bacteria, enterococci, organotrophic bacteria, water level, surface water, monitoring
Abstract
The water quality in the Listvennichnyi Bay has been investigated in terms of sanitary and microbiological indicators during the period of open water in the years of extreme water level in Lake Baikal (2017-2021). It was shown that the degree of fecal pollution in the Listvennichny Bay didn’t correlate with the water level or temperature, but related to the season and significantly varied on the different sampling stations. The abundance of sanitary-indicatory microorganisms in the summer-autumn period was significantly higher compared to the spring period which could be due to the raising anthropogenic impact through the season. Maximum abundance of thermotolerant coliform bacteria and Enterococci was determined at two sampling stations where raw waste waters reached the lake. At the other sampling stations including the background monitoring station, the water quality was mostly consistent with the SanPiN 1.2.3685-21 requirements. The interannual dynamics showed no significant differences in the thermotolerant coliform bacteria and Enterococci abundance. In the period of extremely low water level in Lake Baikal (2017) the abundance of autochthonous and allochthonous organotrophic microorganisms was significantly higher compared to the high-water years (2018-2021). Also, the abundance of both groups of microorganisms was similar in the autumn period, which can indicate the pollution of the Listvennichny Bay with easily decomposable organic matter and incompleteness of self-purification processes.
|
