On the Mercury Content in Surface Waters of the Lake Baikal Basin Based on the Results of Expeditionary Research

This paper presents an analysis of the distribution of the dissolved form of mercury in the surface waters of Lake Baikal basin. In the summer of 2022, surface water samples were taken at 14 stations located on the territory of the Baikal State Natural Biosphere Reserve and in the lake's water area. The analysis of the dissolved form of mercury was carried out using the analyzer RA-915M in the laboratory of the Institute of Earth Sciences of the Southern Federal University. The results demonstrated a variability of values - from 0,002 to 0,042 µg/l (on average 0,019 µg/l). Maximum levels were recorded in river waters, while minimum values were observed in lake waters. No exceedances of the maximum permissible concentrations (MPC) for fishery reservoirs and drinking waters were detected at five of the fourteen stations, including one on Lake Baikal. In other cases, point exceedances were noted, reaching 4.2MPC for fishery reservoirs. Natural and anthropogenic sources of mercury supply to the lake's drainage basin have been identified.