Determination of oil and oil products total content in soils for monitoring of contamination and effectiveness of remediation
Authors: Samokhvalova V. L. , Fateev A. I. , Samokhvalova P. A. , Mandryka O. V. , Bublyk V. D. , Kutz O. 
Published: February 2020

The method of determining the content of oil and petroleum products in the soils is substantiated through the use established by thermogravimetric curves optimum temperatures and time intervals thermal sample of contaminated soil, determination of total losses its weight on the appropriate formula which ensures the quantitative determination of total content level of hydrocarbons of oil and oil products in the soil with increased accuracy and quick testing of the method. In the methodical approach by combining individual components of the known methods thermogravimetry and gas chromatography, the distribution regularities of changes in the sample mass under the influence of thermal effects on a new class of objects with simultaneous production of a rapid method for determination of total content of petroleum hydrocarbons in soils, provided simplification soil samples algorithm analyzing for pollution monitoring and the remediation effectiveness of obtaining the economic use of resources. The invention belongs to the field of environmental protection, soil quality, namely to the ways of determine the content of oil and petroleum products (diesel, kerosene, fuel oil, etc.) in contaminated soils while of soils lands plot monitoring. The method can be used in the field of conservancy in the oil industrial complex in determining the degree of contamination of soil for rapid analysis of soil samples; in agroecology, soil ecological management for environmental monitoring of technologically contaminated soils of lands plots for various purposes and their using; in research practice - to investigate the  thermal processes and properties of soils; elaboration of scientific and methodical bases of contaminated soils monitoring (diagnosis, assessment, forecast ecological state), environmental regulation of organic nature contaminants in soils; regulation of the using and soil remediation processes to improve quality. Based on the analysis of the scientific literature data and results of long-term experiments it was determined the optimal temperature range of 280–500 ○C with different temperature ranges of thermal evaporation the fractions of petroleum hydrocarbons. Series conducted modeling experiments with varying temperature, time, sample the soils and the changing quantitative and qualitative composition of hydrocarbons in contaminated soils, the total petroleum hydrocarbons thermogravimetric method has been found that the thermal degradation of contaminated soils samples formed various fractions of hydrocarbons, which leads to increased losses mass Dm contaminated soil sample to obtain thermogravimetric curves. By the method of gas chromatography, in the range of 100–200 ○C it is set the selective extraction of lighter fractions of petroleum and petroleum products in the soil; in the range of 280–350 ○C – it is noted a sharp increase in the rate of decomposition of oil saturated hydrocarbons (C10–C40) with intensive gas evolution, the formation of a mixture of reaction products is a significant amount of unsaturated hydrocarbons. Thus, the use of established ranges of determining the optimum temperature desorption fractions of petroleum hydrocarbons and their thermal degradation of soil samples for thermolysis with simultaneous identification of the total content of oil and petroleum products in the soil, it is possible to determine the total amount of oil hydrocarbons fractions in soil as the amount of oil hydrocarbons. The proposed algorithm method is suitable for the soils of different genesis. It is determined that the consistent increase in temperature is a necessary procedure for the identification of pollution if soil sample analysis of the expected low concentrations of oil and petroleum products and water content in soils of different types and different size distribution of more than 5 % of oil production zones. By evaluating the flow of thermal processes in the surveyed contaminated and uncontaminated soil samples the temperature ranges degradation of petroleum hydrocarbons is determined. Their using, as an indicator, significantly reduced the timing of selection of optimal technological parameters of thermal oils in the soils for determining the total content of oil and petroleum products in the soils, pollution monitoring and remediation efficiency control.