Impact of motor vehicles on the ecological state of soils in the Western District of Moscow
Ecological and geochemical studies of salinization, contamination with heavy metals and metalloids (HMMs) and the composition of soil algae and cyanobacteria in soils near roadways with different traffic intensities and in courtyards with parking lots were carried out in the Western Administrative District of Moscow. Application of deicing reagents on roads leads to the alkalization (pH 6,9-7,4) and salinization of soils in WAD. The highest concentration of water soluble salts was observed in spring at a depth of 20- 30 cm (the sum of ions equals to 0,15%). The ions of Са<sup>2+</sup>, Na<sup>+ </sup>and HCO <sup>-</sup>, NO <sup>- </sup>and Cl<sup>- </sup>dominate the salt 3 3 3 composition. In autumn, the maximum of salts shifts to the upper soil layer with the dominance of Са<sup>2+</sup>, Mg<sup>2+ </sup>and HCO <sup>-</sup>. Motor vehicle emissions in WAD are the main source of contamination of roadside soils with W, Sb, Cu and Zn, average concentrations of which (3,0, 1,0, 29,8 and 120 mg/kg) are 1,7-2,8 times higher than the background level. The soils of WAD are characterized by low salinity and non-hazardous level of contamination with HMMs (Zc 9,2), without significant differences in the accumulation of readily soluble salts and HMMs near roads with different traffic intensities. Algal-cyanobacterial communities in roadside soils are dominated by species resistant to the alkaline reaction of the environment, salinity, pollution, high insolation and low humidity, thus indicating rather high level of anthropogenic load on soils.