Monitoring of the polycyclic aromatic hydrocarbons content in chernozem soils under longterm industrial pollution

Studies of polycyclic aromatic hydrocarbons (PAHs) content in soils adjacent to power plants is essential to determine the environmental risks. The monitoring was carried out over 3 years on the territory under the emissions of Novocherkassk Power Station (NPS). A significant excess in the PAHs content (up to 84-86%) in the soils under long-term industrial pollution was found compared to the background soil. The total PAHs content in the NPS emissions zone soils increased from 3553.1±25.4 to 4137.0±37.6 μg kg-1 at the most contaminated area located 2.1 km away from the enterprise in the prevailing wind direction. The increment was mostly observed in the content of high molecular weight (HMW) PAHs near the territories used for agricultural production. The LMW PAHs/HMW PAHs ratio of more than 1 indicates PAHs natural origin in the reference area soil. Moreover, it was found that in the NPS emissions zone soils the LMW PAHs/HMW PAHs ratio was 0.12-0.34 on the average, which is less than 1, that shows an anthropogenic origin of PAHs. The increase of this ratio with distance from NPS indicates lower anthropogenic pressure on the soil with longer distance from the emission source.