Approaches to Determining Maximum Permissible Concentrations of Oil and Oil Products for Different Soil Types on the Basis of the Assimilation Potential (by the Example of Azerbaijan Soils)

The assimilation potential to oil and oil hydrocarbons is assessed for the first time for different soil types of Azerbaijan. The soil assimilation potential is understood as the buffering capacity of soils to sustain a certain anthropogenic impact without changing their principal properties and ecological functions for a long period. Estimation of assimilation potential of a territory is necessary for assessing the actual self-purification capacity of environmental components as a national ecological resource under the conditions of constantly growing anthropogenic impact on the environment. For assessing the assimilation potential of soils in respect to oil hydrocarbons, the value of bacterial biodegradation of oil hydrocarbons has been evaluated according to the amount of hydrocarbon-oxidizing bacteria and the number of hydrocarbons that are oxidized by one bacterial cell. It is found that the assimilation potential of different soil types in Azerbaijan (provided they are contaminated with oil hydrocarbons) varies from 1 t/ha per year for solonchaks to 12.5-13.1 t/ha per year for chestnut (Kastanozems) and mountain chernozemic (Chernozems) soils. The index of actual assimilation potential for various soil types may be accepted as the upper safe level of the permissible hydrocarbon concentration.