Influence of anthropogenic activity on the quality of rivers in Listvyanka settlement (South Baikal)

This paper presents the results of microbiological studies of the water quality of four tributaries of Southern Baikal, Listvenichny Bay. Monthly monitoring from October 2022 to July 2025 showed a decline in the water quality and an increase in the number of sanitary-indicative groups of microorganisms in the estuary part of rivers relative to the reference area above the influence of Listvyanka settlement. Thus, the number of coliform bacteria (CB) on average in rivers increases by 17 times, E. coli – by 55 times, and enterococci – by 11 times. In recent years, the water quality in the Malaya and Bolshaya Cheremshanka Rivers remains low. Thus, in comparison to the study of 2015-2016, the maximum values of enterococci abundance increased by 3 times, the number of E. coli - by 2 times and 23 times, respectively.