Spatial Variations of the Activity of 137Cs and the Contents of Heavy Metals and Petroleum Products in the Polluted Soils of the City of Elektrostal

Abstract

The levels of specific activity of 137Cs and the contents of mobile forms (1 M ammonium acetate extraction) of heavy metals (Zn, Cu, Ni, Co, Cr, Pb) and petroleum products were studied in the upper soil horizon of urban landscapes of the city of Elektrostal under conditions of local radioactive and chemical contamination were studied. In the soils within a short radius (0–100 m) around the heavy engineering plant, the specific activity of 137Cs and the contents of mobile forms of Pb, Cu, and Zn were increased. The lognormal distribution law of 137Cs was found in the upper (0–10 cm) soil layer; five years after the radiation accident, the specific activity of 137Cs varied from 6 to 4238 Bq/kg. The coefficients of variation increased with an increase in the degree of soil contamination in the following sequence: Co < Ni < petroleum products < Cr < 137Cs < Zn < Pb < Cu ranging from 50 to 435%. Statistically significant direct correlation was found between the specific activity of 137Cs and the contents of mobile forms of Pb, Cu, and Zn in the upper horizon of urban soils, and this fact indicated the spatial conjugacy of local spots of radioactive and polymetallic contamination in the studied area. It was shown that the specific activity of 137Cs, as well as the content of heavy metals and petroleum products in the upper layer (0–10 cm) of the soils disturbed in the course of decontamination, earthwork and reclamation is reduced.