Mercury in atmospheric air and precipitation at the monitoring station Listvyanka (Southern Baikal region) in 2022-2023
E.S. Lutskin, M.Yu. Shikhovtsev, Ye.V. Molozhnikova, V.A. Obolkin, O.I. Berdashkinova, T.V. Khodzher
Limnological Institute of the Siberian Branch of the RAS, Irkutsk, Russia
Keywords: gaseous elemental mercury, total mercury, precipitation, atmospheric air, HYSPLIT, Southern Baikal Region
Abstract
Gaseous elemental mercury (GEM) is the predominant form of mercury in the atmosphere. As a result of deposition, it enters terrestrial and aquatic ecosystems, where it is further transformed into the ecotoxicant methylmercury. The work is devoted to the study of gaseous elemental mercury (GEM) in atmospheric air and total mercury in atmospheric precipitation in the Southern Baikal region. Sampling was carried out at the monitoring station Listvyanka (51.9° N, 104.4° E) in 2022-2023. Mercury concentration in air was measured by mercury gas analyzer RA-915AM (St. Petersburg, Russia). The concentration of total mercury in precipitation was determined by PND F 14.1:2:4.271-2012, method A (permanganate mineralization). Statistical analysis of data on mercury content in atmospheric air and precipitation is performed. During the period under study, the concentration of GEM in atmospheric air averaged 1.61 ng/m3. The analysis showed that the pair correlation coefficient throughout the period under study was 0.47 between Hg0 and sulfur dioxide (SO2) and 0.44 between Hg0 and nitrogen dioxide (NO2). In 12 cases, a strong positive correlation (> 0.9) between Hg0, SO2, and NO2 was observed. For each episode of mercury concentration above 2.0 ng/m3, back trajectories of air masses were calculated using the HYSPLIT model. The trajectory analysis also confirmed our assumption of a common type of source for mercury and minor gas impurities. The weighted average content of total mercury in precipitation is 44 ng/L, the median value is 29 ng/L, and the maximum is 282 ng/L. We have supplemented the existing ideas about mercury content in the atmosphere of the Southern Baikal region. It was found that despite the significant distance from large cities, the mercury content in atmospheric precipitation on the shores of Lake Baikal is comparable to the results obtained in urban agglomerations of Nepal, Canada, Korea, and China.
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