There are unique types and subtypes of soils within the territory of the Crimean Peninsula. The growing tourist pressure on the region requires the increasing productivity of all industries, including oil refining. All this increases the risk of spills and leaks of oil and petroleum products during their transportation and pumping. However there is a large gap in the field of regulation of soil pollution with petroleum products (gross content), i. e. the absence of maximum permissible concentrations in the regulatory framework of the Russian Federation. To predict possible negative consequences of environmental pollution with oil and oil products, it is necessary to develop regional environmentally safe concentrations of oil and oil products, with due con[1]sideration of the local ecological and geochemical characteristics of soil types. The purpose of the study is to find the environmentally safe content of fuel oil in the soils of Crimea. Fuel oil contamination (1, 5 and 10% of the soil mass) was simulated in laboratory conditions. The study examined 7 types of Crimean soils, namely residual carbonate chernozem, drained solonetzic chernozem, dark chestnut solonetzic soil, brown carbonate soil, brown leached red soil, brown forest acidic soil and underdeveloped chernozem. After 30 days of the model experiment, the most informative biological indicators were determined in soil samples, i.e. biochemical (activity of catalase and dehydrogenases), microbiological (total number of soil bacteria and Azotobactersp. abundance) and phytotoxic (root length) indicators. It was established that fuel oil pollution had a negative impact on the biological properties of studied soils. The following series of soil resistance to fuel oil pollution has been obtained: residual-carbonate chernozem ≥ solonetzic drained chernozem = dark chestnut alkali = brown leached red-colored ≥ underdeveloped chernozem ≥ brown carbonate soil > brown forest acidic soil. The values of the maximum permissible levels of residual fuel oil content (MRLC) in the soils of Crimea were obtained: 0,33% in residual carbonate chernozem, 0,30% in dark chestnut solonetzic soil and solonetzic chernozem, 0,28% in brown carbonate soil, 0,35% in brown leached red soil, 0,33% in underdeveloped chernozem, 0,21% in brown forest acidic soil. The results of the study could be used in biodiagnostics of the ecological state and health of soils polluted with fuel oil.
