Variability in acidity of precipitation on the territory of the Far Eastern Federal District of Russia
I.I. KONDRATIEV, A.N. KACHUR
Pacific Geographical Institute, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
Keywords: acidity, precipitation, monitoring, wet precipitation of nitrogen and sulfur, transboundary atmospheric transport
Abstract
An analysis is made of the variability of the acidity index of precipitation and fluxes of wet sulfur and nitrogen deposition on the territory of the Far Eastern Federal District of the Russian Federation (FEFD). The analysis used data Roshydromet (Hydrometeorological Service of Russia). It was found that alkaline precipitation was characteristic for most of FEFD (Yakutia and Transbaikalia). However, an increase in the acidity of precipitation was observed in the south-east of the region during the period under consideration. The average annual pH values of precipitation in Primorsky krai dropped below 5.6 in the first decade of the 21st century to reach in separate years 4.6-4.7 at some of the monitoring stations. It is pointed out that the ever-increasing use of nitrogen fertilizers in East Asian countries leads to an increase in the flow of atmospheric nitrogen deposition, which negatively affects forest vegetation. The annual flux of wet deposition at the international monitoring station EANET Primorskaya between 2006 and 2015 was 6.37 kg/ha per year for S deposition and 6.3 kg/ha per year for N (nitrate+ammonium). Similar values were obtained by averaging data from all stations in Primorsky krai. In 2018, this flux exceeded a critical value of 10 kg/ha per year. The Ternei monitoring station located in the Sikhote-Alin Biosphere Reserve observed the amount of nitrogen fluxes twice as lower as that at the Primorskaya station, but order of magnitude higher than the values recorded in the western part of FEFD. The determining factor for an increase in the acidity of precipitation and for the high levels of nitrogen depositions in the south-east of FEFD is the transboundary atmospheric transport of pollutants from the centers of anthropogenic emissions in East Asia. The analysis of data made in this paper is in agreement with reports of Roshydromet on the state and pollution of the environment of the Russian Federation and supplements and details them.
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