Benzo[a]pyrene contamination in Rostov Region of Russian Federation: A 10-year retrospective of soil monitoring under the effect of long-term technogenic pollution

The aim of the current work was to study the main tendencies in the accumulation and distribution of benzo[a]pyrene in soils of the affected zone of the Novocherkassk regional power plant. Studies were conducted on the soils of monitoring plots subjected to Novocherkassk regional power plant emissions. Monitoring plots were established at different distances from the Novocherkassk regional power plant (1.0–20.0 km). Regularities in the accumulation and distribution of benzo[a]pyrene in chernozemic, meadow-chernozemic, and alluvial soils under the effect of aerotechnogenic emissions from the Novocherkassk regional power plant have been revealed on the basis of long-term monitoring studies (from 2002 to 2011). The tendencies in the distribution and accumulation of BaP in the studied soils coincided during the 10 years of monitoring studies. It has been found the 5-km zone to the northwest from the power station, which coincides with the predominant wind direction, is most subjected to contamination by benzo[a]pyrene, with the maximum accumulation at a distance of about 1.6 km from the source. Dynamics of pollutant accumulation in soils depends on number of Novocherkassk regional power plant emissions. The content of benzo[a]pyrene in the soil is an indicator of the technogenic load impact on the areas, for which the combustion products of hydrocarbon fuel are the major pollutants. A gradual decrease of the pollutant content in the soils was revealed during the period from 2002 to 2011. It explained by the significant decrease in the volume of pollutant emissions from the plant and the self-purification capacity of soils and mechanisms of benzo[a]pyrene degradation.