Home – Home – Jornals – Geography and Natural Resources 2023 number 4

The content of 14 polycyclic aromatic hydrocarbons (PAHs) in the soils of the city of Severobaikalsk (Republic of Buryatia) was studied for the first time and an ecological and geochemical assessment of their pollution in different land-use zones of the city was made. The main sources of PAHs were determined, namely the emissions from the heat and power complex operating on Kansk-Achinsk brown coal, railway and motor transport, and from oil depots, which form extensive high-contrast PAH anomalies in the soils in the north-east, north-west, and south of the city. Fluoranthene, benzo(b)fluoranthene, and phenanthrene predominate in the composition of brown coals used; the amount of PAHs in them is 5.44 mg/kg; in the ash of the thermal power plant it is 20 times less than in the brown coals. In the upper (0-10 cm) soil horizons of Severobaikalsk, the total content of PAHs averages 0.441 mg/kg, which is 4 times higher than the background level. The composition of PAHs in urban soils does not differ from their natural analogs with the predominance of fluoranthene, pyrene, and benzo(b)fluoranthene. The sum of 2-4-ringed PAHs is 1.5-2.9 times higher than the sum of 5-6-ringed ones. The degree of soil pollution with PAHs is caused by the level of technogenic load, which depends on the functional status of the territory. It is concluded that the soils of residential manor and industrial zones are most heavily polluted with PAHs whereas the least polluted are those of the residential multi-storey zone. The content of BaP in the soils of the industrial zone exceeds the MPC on average by a factor of 1.5, and in the residential manor zone by a factor of 1.3. The maximum exceedances reach 31 MPC in the northeastern anomaly. When taking into account the contribution of other PAHs, expressed in terms of the equivalent amount of BaP in soils, the average frequency of exceeding the MPC for BaP increases to a factor of 2.3, and in the industrial and residential manor zones, to factors of 3.4 and 3.6, respectively. 34 % of the city’s soils are characterized by an acceptable pollution level, and 23.4 % by a dangerous and very dangerous levels of PAH pollution, which threatens public health and can cause deterioration of the water composition in Lake Baikal.