Effect of selenium application on some oxidoreductive enzymes in loamy sand contaminated with diesel oil

The aim of the study was to assess the impact of diesel oil on the activity of oxidoreductases in loamy sand, and to evaluate effect of selenium addition in the restoration of homeostasis of soil contaminated with diesel oil. The experiment was carried out under laboratory conditions with loamy sand. 0.05 mmol/kg of selenium (Se(IV) or Se(VI)), and diesel oil in the doses of 2, 10 and 50 g/kg were added to the soil samples. In soil treated with selenium and diesel oil activities of dehydrogenases, catalase, o-diphenol oxidase and nitrate reductase were measured on 1, 7, 14, 28, 56 and 112 day of the experiment. Contamination with diesel oil did not cause significant changes only in the activity of o-diphenol oxidase. The highest increase was observed in activity of dehydrogenases. Selenium limited hydrocarbons impact on activity of soil oxidoreductases, especially in loamy sand with diesel oil in the dose of 10 g/kg. Obtained results showed that this effect was reduced after treatment with selenium in both oxidation states but for nitrate reductase and catalase this reduction was reported after application of Se(VI) and Se(IV), respectively.