Differentiation of the saturated and aromatic compounds composition during oil infiltration into sod-podzolic soils (for a local oilfield site in the Nefteyugansk District of the Khanty-Mansi Autonomous Area as an example)
D. V. FEDOROV, O. V. SEREBRENNIKOVA, N. A. KRASNOYAROVA
Institute of Petroleum Chemistry, Siberian Branch of the Russian Academy of Sciences, Tomsk, Russia
Keywords: soil, oil pollution, depth profile, composition of pollutants
Abstract
The distribution patterns of saturated and aromatic hydrocarbons in sod-podzolic soils one year after an accidental oil spill at an oil field in the Nefteyugansk district of the Khanty-Mansi Autonomous Okrug are considered. Soil samples were collected from the depth of 0-10, 10-30, and 30-50 cm. The composition and distribution of hydrocarbons were determined using gas chromatography-mass spectrometry. The total pollutant content was found to be unevenly distributed: the highest concentrations are confined to the surface layer, while the minimum values are characteristic of the middle interval (10-30 cm). In all horizons, n-alkanes account for the majority of the contamination, while isoprenoid alkanes and polycyclic aromatic compounds are present in smaller quantities. It has been shown that in the intermediate (10-30 cm) layer, the ratio of individual aromatic compounds changes: in particular, the contribution of methyl-substituted naphthalene homologues decreases and the relative content of phenanthrene homologues increases. Predominance of high-molecular-weight odd n-alkanes, characteristic of biogenic soil organic matter, was also recorded in this layer. Individual n-alkanes include homologues from C13 to C35. It has been found that the average number of carbon atoms in homologous series for compounds with long alkyl chains increases for most groups of compounds when moving from oil to soil.
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