Response of Avena sativa, microorganisms and enzymes to contamination of soil with diesel oil

The scale of the impact of petroleum products on the natural environment is still difficult to determine. This is why it was decided to conduct tests, under the conditions of a pot experiment, for the effects of diesel oil (0, 4, and 8 mL/kg dry matter of soil) on the yield of oat, content of macroelements, as well as the microbiological, biochemical, physicochemical and chemical properties of the soil. The study results showed that diesel oil had an adverse effect on the growth and development of oat, and contents of nitrogen, sodium, calcium and magnesium in the above-ground parts of oat. Diesel oil increased the concentration of the following substances in the soil: naphthalene, phenanthrene, anthracene, benz[a]anthracene, chrysene, benzo[a]fluoranthene, benzo[a]pyrene and benzo[ghi]perylene, organic carbon, total nitrogen, and available potassium, while it decreased the concentration of available phosphorus and magnesium in the soil. Changes in the physicochemical properties of the soil had an unfavourable effect on the microbiological and biochemical properties. As regards the 7 tested enzymes, the most sensitive to diesel oil was catalase, and the least sensitive ones were ß-glucosidase and dehydrogenases. As for 12 various tested microorganisms, bacteria of the Azotobacter genus exhibited the highest resistance, while copiotrophic bacteria the lowest.