Values of concentrations of mobile forms of some heavy metals under conditions of local oil pollution of soils of the middle taiga subzone of Western Siberia

The article considers the influence of oil pollution on the ecological functions of soils and the distribution of mobile forms of heavy metals (HM) in the upper horizon (0–20 cm) in the middle taiga subzone of Western Siberia. The conducted analysis revealed 100% excess of concentrations of all studied heavy metals relative to the background and maximum permissible concentrations (MPC) even in the zone of minimal pollution (pollution boundary): lead (1.1–1.3 MPC), zinc (1.0–1.2 MPC), copper (1.3–1.9 MPC), nickel (2.0–2.4 MPC), vanadium (3.9–5.1 BACKGROUND) and manganese (3.3–4.1 MPC) compared to background values and maximum permissible concentrations (MPC). The reference results for extrapolation and identification of degradation processes in the soil cover are the concentration values of mobile forms of toxic elements. The results of the study emphasize the need for regular monitoring and development of measures to restore oil-contaminated soils, including the use of reclamation and bioremediation methods, which are often recommended in such situations. Based on the data obtained, integral indicators of soil pollution were calculated: the total pollution index (Zc) and the geoaccumulation coefficient (Igeo). The results of the study showed that individual zones with high and extremely hazardous pollution were identified in the studied area. Particular attention was drawn to the elements Zn, Mn and V, which demonstrated consistently elevated values according to Igeo, which indicates their significant role in the formation of technogenic load and a potential threat to the environment.