The distribution and behavior of mercury in snow

With atmospheric precipitation to 28% of mercury (from their total input into this basin) is transported to the Azov Sea via precipitation [1,2]. There is an increasing tendency in the mercury concentrations in rain and snow sampled in the cities of the Rostov Region, compared to precipitation over the sea and its coast. The maximum mercury concentrations in the hydrometeors were found in the cities in autumn and winter. It is due to its penetration into the troposphere as a result of the rapidly increasing dust amounts and gas emissions sourced by combustion of coal, fuel oil, and gas during the heating season. The mercury concentrations in the hydrometeors are higher in stale snow than in just-fallen snow. It is suggested that stale snow is a depositing material absorbing mercury from the troposphere, where it accumulates due to activity of various enterprises with pollutant emissions. This statement is confirmed indirectly by the fact that the Donbass coals are characterized by high mercury concentrations [1]. Another mechanism could be mercury re-distribution during the compaction of snow cover and its interaction with soil. In the course of the winter expeditions, a clear snow stratification was registered: just-fallen powder and stale crystallized grey snow with a large amount of mineral and organic material. In stale snow, the dissolved and suspended form of mercury migration prevailed over its content in freshly fallen snow. The mercury content in hydrometeors was influenced by such factors as wind activity and the amount of atmospheric precipitation. On the one hand, when wind activity increases, the atmosphere surface layers in the cities are cleared from technological substances, and the input of soil particles increases during dust storms. There is intensive mercury leaching from the atmosphere during torrential rains. It leads to a sharp decrease in its atmospheric concentrations. On the other hand, there is an increase in the mercury content in the rainfall after a dry period under calm weather conditions.

The work was carried out with the financial support of the RF President grant No. MK-1862.2020.5., RFBR projects No. 19-05-50097.

Литература

• [1]. Fedorov Yu. A., Mikhailenko V., Dmitrik L. Y., Dotsenko I. V., Solodko D. F., Chepurnaya V. I. Mercury and iron in precipitation of the Azov Sea basin// Limnology and Freshwater Biology, 2020,№1,pp. pp.838-839.
• [2]. Klenkin A. A., Korpakova I. G., Pavlenko L. F., Temerdashev Z. A. Ecosystem of the Sea of Azov: anthropogenic pollution. Krasnodar: "Enlightenment-SOUTH", 2007. – 324p.