Spatiotemporal peculiarities of sulfate and nitrate concentration in soils of urbanized areas

Assessment of the current state of soils of urban areas revealed spatial differences in the accumulation of nitrates and sulfates by administrative regions of the country. The lowest nitrate concentrations were observed in the cities of Brest region (Kc = 0.5), the highest – in Gomel region (Kc = 2.8). The opposite trend was observed for sulfates: the lowest average content was recorded in the cities of Gomel region (Kc = 1.0), the highest – in Brest region (Kc = 1.5). At the same time, the differences in the accumulation of sulphates by regions are insignificant, while for nitrates the variation of average values amounted to more than 5 times. Maximum values of sulphates observed in some parts of the cities were from > 1,0 to 3,0 maximum permissible concentrations. Studies have shown that over the period 2000–2020, 90 % of populated areas showed a tendency to decrease to concentration nitrates in urban soils. It can be assumed that such a decrease in nitrogen-containing substances is due to a decrease in the amount of organic matter in soils and slowing down of nitrification processes during its decomposition, as well as an insignificant proportion of nitrogen-fixing organisms present in urban soils. It was found that over the study period, the content of sulfates in urban soils increased. At the same time, in 59 % of cases, soils were characterized by a significant increase in the content of sulfates, in 41 % of cases, the accumulation of sulfur-containing compounds in soils was insignificant. In the soils of Minsk for the period 2000–2022, multidirectional trends in the content of nitrates were established by year with a general tendency towards a significant decrease in their concentration. For sulfates, some accumulation was noted in soils with an insignificant decrease in concentrations in 2013 and 2015. In general, it is possible to predict a deterioration in the ecological state of soils in 94 % of the studied settlements due to an increase in the concentration of sulfates in them and a positive trend expressed in a decrease or stabilization of the accumulation of nitrates in the soil cover of urban areas.