Benzo[a]pyrene accumulation and transformation in Chernozem ordinary under artificial pollution

The aim of the study. The aim of the study was to evaluate the benzo[a]pyrene (BaP) accumulation and transformation rate and pathways in soil under the model experiment conditions with artificial pollution. Location of the study. The work was carried out in the Academy of Biology and Biotechnology, Department of Soil Science and Land Resources Assessment, Southern Federal University (Rostov-on-Don), and in the Botanical Garden, Southern Federal University (Rostov-on-Don, Russia). Methodology. Extraction of BaP from the soil was carried out by the saponification method. The qualitative and quantitative determination of BaP and other polycyclic aromatic hydrocarbons (PAHs) was performed by High Performance Liquid Chromatography with fluorescence detection. Main results. The study showed that BaP accumulation in ordinary chernozem depended on the rate of pollutant addition. The first year of the experiment showed 11-40% decrease in the soil BaP concentration, and two years later soil BaP concentration was found to decrease down to 15-44% from the initial soil BaP content. The relative soil BaP concentration decrease was found to increase with increasing rate of xenobiotic addition, and to decrease in the second year of the experiment. The increased rate of BaP addition into the soil of the model experiment led to the increase in other high molecular mass polyarenes, which indicated a fairly rapid BaP transformation in the Chernozem Ordinary. The soil PAHs content in the first year of the model experiment could be ranked as: pyrene> chrysene> fluoranthene> phenanthrene, with their bulked content exceeding 20% of the total soil PAHs content. In the second year of the experiment, a different rank pattern was observed in priiority PAHs: pyrene> chrysene> phenanthrene> fluoranthene, with their bulked content exceeding 20% of the total soil PAH content. Conclusion. The content of all PAHs, mostly of high molecular mass polyarenes, in the artificially polluted soil of the model experiment, increased with the increased rate of pollutant application, indicating a rather high degree of xenobiotics accumulation by Chernozem Ordinary. The PAHs accumulation and transformation in soil under artificial pollution showed the degradation of polycyclic PAHs into polyarenes with less number of rings (2-4 rings). During the two years of the model experiment, the concentration of BaP in the soil decreased up to 9–44%, indicating high potential of chernozemic soils for benzpyrene decomposition.