Assessment of the level of soil contamination with petroleum hydrocarbons (Using the example of oil-contaminated soils in the Aral Sea region)

Abstract

The article presents the results of research of the hydrocarbon composition of petroleum extracted from contaminated soils of oil fields in the Aral Sea region. The work has been carried out to assess the level of contamination with petroleum hydrocarbons and determine various approaches to their remediation, taking into account the nature of their use. The gravimetric method has been used to determine the oil content in contaminated soil, which is 66866.60 mg/kg and 26296.66 mg/kg for the soil of the Kumkol and Taur oil fields, respectively.Using a gas chromatography-mass spectrometer “Agilent” - 7890A/5975C, the petroleum hydrocarbon compositionin soil samples has been studied. Based on the research findings, it has been determined that oil extracted from contaminated soil of the Kumkol field contains 80.10% alkanes, 6.10% naphthenes and 5.90% arenes. Oil extracted from contaminated soil of the Taur field contains 85.39% alkanes, 6.70% naphthenes and 0.59% arenes. Also, the studied oil samples contain oxygen-, sulfur-, and halogen-containing hydrocarbon derivatives in the ratio of 7.90 and 7.32, respectively.The results of gravimetric and chromatographic analysis ofpetroleumextracted from contaminated soil show that the level of soil contamination with residual petroleum products creates a dangerous level of benz(a)pyrene formation and the substrate acquires toxicity properties. Very negative conditions for the development of zonal plants, a nonequilibrium maximum optimum for oil-oxidizing microorganismsare formed. The water and air regime of soils changes and full-scale remediationactions and activation of the microbial communityare required. It is necessary to control the migration of petroleum hydrocarbons, especially benz(a)pyrene. From the point of view of environmental protection, a certain approach to their remediation is required, taking into account the nature of use.