Home – Home – Jornals – Chemistry for Sustainable Development 2020 number 3

The destruction of organic matter in oil-contaminated clay soil by native microflora was studied under laboratory conditions. Peat and the solution of a composition containing a surfactant and a nitrogenous substrate, as well as their combination with phytoremediation, were used as stimulating additives. After biodegradation, the residual oil was extracted and examined by means of IR spectroscopy, gas-liquid chromatography (GLC) and chromatography-mass spectrometry. According to the data of IR spectroscopy, peat and a solution of the composition promote the utilisation of paraffins, which is accompanied by an increase in the relative content of aromatic and carbonyl-containing structures. The isoprenoid coefficient K_i , which reflects the degree of hydrocarbon biodegradation, was calculated from GLC spectra as the ratio of iso- and n -alkanes. It increases with the introduction of stimulating substrates and soil loosening. The maximal biodegradation (biodestruction) coefficient is observed for the sample of oil-contaminated clay soil containing the surfactant composition, which contributes to oil emulsification and accelerates biodegradation. Acyclic ( n- and isoalkanes), alicyclic (cyclohexanes, drimanes, cheilanthanes, regular and rearranged steranes and hopanes), naphthenoaromatic (mono- and triaromatic steranes), and aromatic (mono-, bi-, tri-, tetra- and pentacyclic) hydrocarbons were detected in the soil organic compound (SOC) by means of chromatography-mass spectrometry. As a result of biodestruction stimulated by the introduction of peat and the nutrient substrate, the concentration of hydrocarbons decreased significantly: n-alkanes - by 74-82 %, aromatic compounds - by 97-99 %, cyclohexanes - by 78-92 %, oil steranes and hopanes - by 88-97 %. The introduction of the composition containing a nitrogenous substrate and a surfactant into the soil leads to a significant decrease in the content of C₁₂-C₃₄ alkanes to the level of background soil. The introduction of peat additive veils (shades) the results of alkane oxidation due to their presence in peat itself. The use of stimulating substrates leads to a decrease in the content of aromatic hydrocarbons during biodegradation: monocyclic by 82-89 %, bicyclic - by 55-81 %, tricyclic - by 74-89 %, tetracyclic - by 54-77 %.