Depending on a method for determining oil products and chemical features of an extraction agent, research of the same soil samples has shown different results. The highest values of oil products analyzed using carbon tetrachloride on a concentration meter AN-2 may indicate the most complete determination of gross content. Hexane extraction in determining oil products on spectrofluorimeter «Flyuorat-02» has shown the lowest values of all three methods. The proportion of soluble fractions which

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... e in a mobile state or in the dissolved phase (summing up the results of their determination on «Flyuorat-02») can be called a mobile fraction (OPm). The high proportion of OPm (over 50%) in the topsoil can serve as a diagnostic indicator of permanent income of oil products to the soil. As a result of autoclaving at temperatures up to 170 °C and a pressure of 1,5 atm volatile fractions evaporate (OPv). In uncontaminated virgin soil oil is a fraction of organic compounds of the soil. The oil volatiles have not been defined that may be a diagnostic indicator of the lack of intoxication soils.