ИСТИНА

The most environmentally dangerous consequence of anthropogenic halogenesis resulting from the use of de-icing agents in Moscow and other northern cities is their alkalinization due to the entry of exchangeable sodium in the soil absorption complex. As a result, a number of soils acquire more negative properties than under salinity. Anthropogenic alkaline soils have a low natural fertility, a negative impact on green areas, often causing their destruction. Long-term dynamics of anthropogenic alkalinity of soils in the Eastern Administrative District (EAD) of Moscow was studied. The results of soil geochemical surveys of urban and background soils in 1989, 2005, 2010 were analysed. Easily soluble salts in the 160 soil samples were determined by aqueous extract, exchangeable cations – using method of Pfeiffer. The average content (%) of the solid residue of soluble salts in urban soils changed from 0.31 in 1989; 0.39 in 2005; to 0.48 in 2010; the average content (mmol(eq)/100 g) of the exchangeable sodium cation varied within 0.38 in 1989, 0.63 in 2005 and 0.80 in 2010. The background values of these parameters are 0.03 % and 0.13 mmol(eq)/100 g respectively. The degree of alkalinity of soils averages (% of the cations’ sum): 1989 - 3.15; 2005 - 4.92; 2010 - 7.22 compared with 1.38 on the background area of Podmoskovnaya Meschera. The differences in the content of exchangeable sodium in soils of different land-use zones were determined. Maps of anthropogenic alkalinity in soils of EAD of Moscow for three years were compiled detecting long-term trends in alkalinity of urban soils and predicting their further development. The most intense and extensive man-made anomalies with high alkalinity of soils were developed near major highways and industrial zones.