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[MIS01-P13] Seasonal variation in the chemical composition of atmospheric precipitation on the Valday Upland, Russia
Keywords:Valday Upland, chemistry of atmospheric precipitation, seasonal variation, transboundary transfer
Atmospheric precipitation is universal indicator of environmental changes. The assessment chemical composition of atmospheric precipitation contributes to global understanding of major contemporary environmental issues, such as air pollution, acidification and eutrophication of ecosystems and climate change. These issues are of increasing importance as anthropogenic influence growth. To assess the impact of season variation to chemical composition of precipitation, we selected a conditional background area, the center part of the Valday Upland. The study area is located in the European part of Russia away from major sources of pollution. Therefore, data on the composition of precipitation reflect natural and regional regularity of elements distributions. The investigation was conducted using the data from 2015 to 2020. We observed a trend of climate warming during this period. As the amount of precipitation increases, the content of chemical components in it decreases due to the dilution and diffusion movement of elements.
The chemical composition of atmospheric precipitation is characterized by the spatiotemporal variability. Atmospheric precipitation provides uninterrupted replenishment of biogeocoenosis with nutrients. Leaching of substances from leaves or needles, branches or trunks makes a significant contribution to changing the biogeochemical cycle of elements. Geochemical weathering of soils causes an increased content of Si, Al, Ca, Na, K. A positive correlation between the silica concentration and the turbidity index indicates a significant contribution of dust. Intensive enrichment of atmospheric precipitation with organic acids in the warm period leads to a decrease in pH to 4.5. The elevated contents of essential elements (N, Fe, Mn, Zn and Cu) in undertree precipitation indicate a contribution of biogenic factor. The highest Pb, Ni, Cd, and SO4 contents are noted in all precipitation collectors in summer. Summer is characterized by the highest dust load in the studied area and in the entire climatic zone. Therefore, summer season is most suitable for the determination of elements supplying in atmospheric precipitation through transboundary transfer. Statistical processing of obtained data revealed sigificant differences between selected samples in the contents of sulfate and heavy metal ions in spring and autumn. PCCA analysis showed the predominant influence of biogenic factors on the content of most elements in the forest precipitation. The snow cover in small town of Valday reflected the increased precipitation of nitrogen and sulfur-containing components from the atmosphere. By methods of parallel and sequential microfiltration, it was found that forest snow samples contain metal compounds with different molecular weights due to the different contribution of organic substances. The predominant type of metals in urban snow samples were large particles.
The research was conducted by financial backing for grant project Russian Science Foundation No. 22-17-00061.
The chemical composition of atmospheric precipitation is characterized by the spatiotemporal variability. Atmospheric precipitation provides uninterrupted replenishment of biogeocoenosis with nutrients. Leaching of substances from leaves or needles, branches or trunks makes a significant contribution to changing the biogeochemical cycle of elements. Geochemical weathering of soils causes an increased content of Si, Al, Ca, Na, K. A positive correlation between the silica concentration and the turbidity index indicates a significant contribution of dust. Intensive enrichment of atmospheric precipitation with organic acids in the warm period leads to a decrease in pH to 4.5. The elevated contents of essential elements (N, Fe, Mn, Zn and Cu) in undertree precipitation indicate a contribution of biogenic factor. The highest Pb, Ni, Cd, and SO4 contents are noted in all precipitation collectors in summer. Summer is characterized by the highest dust load in the studied area and in the entire climatic zone. Therefore, summer season is most suitable for the determination of elements supplying in atmospheric precipitation through transboundary transfer. Statistical processing of obtained data revealed sigificant differences between selected samples in the contents of sulfate and heavy metal ions in spring and autumn. PCCA analysis showed the predominant influence of biogenic factors on the content of most elements in the forest precipitation. The snow cover in small town of Valday reflected the increased precipitation of nitrogen and sulfur-containing components from the atmosphere. By methods of parallel and sequential microfiltration, it was found that forest snow samples contain metal compounds with different molecular weights due to the different contribution of organic substances. The predominant type of metals in urban snow samples were large particles.
The research was conducted by financial backing for grant project Russian Science Foundation No. 22-17-00061.