Dynamics of microorganisms population in oil-polluted carbonate soils (rendzic leptosols) in the remediation process

Sod-carbonate soil was polluted with oil in the amount of 5, 10 and 20 l/m2. During 8 years of observations the top layer of this soil was characterized by a reduced number of bacteria, while in the composition of biota increased the proportion of micromycetes. Remediation of oil-contaminated soil with the use of a complex preparation «Albit», which has the properties of growth regulator, fungicide and fertilizer, contributed to the increase in the number of bacteria. In the process of self-restoration of the soil, the hydrocarbon content gradually decreased, and with little pollution reached the permissible concentration level. However, on places with higher oil doses, the number of hydrocarbons remained high at 4 and 12 MPCs. Against the background of the biological preparation application in all the years of observation, the amount of residual oil in the soil was 2 and more times lower than without its use. On the 3rd year after the start of remediation, on the background of a low dose of contamination the amount of hydrocarbons is below the permissible concentration. At a higher level of oil pollution, additional support for the activity of hydrocarbon-oxidizing microorganisms, including by loosening, seems to be necessary for the successful restoration of soils. The amount of benz(a)pyrene at the highest level of oil contamination of the soil reached MPC. Through the use of biological preparation, benz(a)pyrene decomposition has accelerated significantly; on variants without its introduction for 8 years, the content of carcinogen decreased significantly.