Polycyclic Aromatic Hydrocarbons in Urban Soils (Moscow, Eastern District)

The content and distribution of 17 individual structures of polycyclic aromatic hydrocarbons (PAH) were determined in the surface soil layers of the Eastern Administrative District of Moscow and in the background soils of the Meshchera Lowland. The maximum contribution to the PAH spectrum in the background soil belonged to the structures with a small number of nuclei mainly of natural genesis. In the urban soils, the mean total PAH was 5385 ng/g; it was 40 times higher than in the background objects. The unsubstituted multinuclear hydrocarbons as compared to homologues accumulated two times more intensely. The total PAH concentration in the soils of different functional zones varied from 4288 (old residential area) to 8655 ng/g (new blocks). The soils of each zone were characterized by a constant composition of polyarenes, which reflected a specific combination of pollution sources. Using the maps of the benz(a)pyrene contents in the soils in different years, two of its contrasting technogenic anomalies were revealed in the northern and central parts of the district. In 2006, in these areas, the benz(a)pyrene concentration exceeded its MPC by 150 times. The ecological hazard of PAH pollution was assessed. The estimate obtained took into account the carcinogenic potential of 13 individual polyarenes by their equivalents with respect to benz(a)pyrene.