Том 71, № 1 (2016)

There are marked differences in the pH values determined in water suspension under laboratory conditions and in soil solution under field conditions in hydromorphic soils (gleysols and stagnosols). The value δpH = pH_susp–pH_sol can be either positive or negative. Among the main factors that affect the value of δpH are the laboratory preparation of soil samples and the suspension effect. The sign of the pH effect (value of δpH) depends on the participation of humus, carbonate, and exchange bases in the formation of aggregates destructed in the laboratory. The value of δpH is negative in noncalcareous soils with low content of exchangeable bases and fulvate composition of humus and positive in calcareous soils or soils enriched with exchangeable bases and humate composition of humus. In cases of a significant δpH effect, the value of pH_susp cannot be regarded as an adequate measure of soil acidity.

The total content and content of mobile forms of potential soil pollutants (Cd, Pb, Zn, Cu, Sr, F, S) are determined in the topsoil in the impact zone of a cement plant and phosphorus fertilizer factory. The total concentration of Cd (4.0 mg/kg), Pb (99.4 mg/kg), F (15.2 mg/kg), and S (479.6 mg/kg) is found to exceed the established maximum permissible concentrations (MPC, APC). The local concentration maximum of the major pollutants is observed at a distance of 0.5 and 1.0 km away from a phosphogypsum stack. Comparing sampling plots equidistant from the pollution source reveals that alluvial soils have accumulated 1.5–2 times more total forms of Cd, Pb, Zn, Cu, S than agrosod podzolic soils.

The stability of the microbial community can be characterized as resistant to the existing anthropogenic pollution. No potential attributes of microbial degradation are identified in the areas where the concentrations of soil pollutants exceed the background level.

The content and distribution pattern of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDE and DDD) in the surface layers of soils in Moscow are studied. The residual content of these substances in the soils varies within 2.22–1440 µg/kg (at a mean value of 158.9 ± 314.1 µg/kg and median 42.53 µg/kg). The correlation between the contents of DDT and its metabolites and DDD and organic matter is revealed. The highest contents of the pollutants are seen in the residential–transport and industrial zones of Moscow, while their lowest contents are revealed in the soils of the yards of preschool facilities and schools. With respect to the residual contents of the pesticide, most of the soils of Moscow can be considered uncontaminated (80.0%) and acceptably contaminated (7.5%).