Oil-Contaminated Soil Bioremediation with Eisenia fetida in the Presence of Lactic Acid and Nitrogen-fixing Bacteria in Laboratory Experiments
||bioremediation, earthworms, oil, biopreparation
The Department of Chemical Technology and Biotechnology, Petrochemical Institute, Omsk State Technical University,
644050, Omsk Russia
The Institute of Hydrocarbons Processing, Russian Academy of Sciences, Siberian Branch, 644040 Omsk, Russia
In this study, the survival, reproductive potential of earthworm species Eisenia fetida in oil-contaminated soil and the effect of earthworms in combination with a biopreparation Baykal EM-1 (Reg. N 226-19-156-1) on the process of total petroleum hydrocarbons degradation have been investigated. In particular, the earthworms were incubated in crude oil-polluted soil containing 20,000 to 100,000 mg/kg of total petroleum hydrocarbons or a reference soil for 22 weeks. The laboratory studies demonstrated high level of the E. fetida survival in the oil-contaminated samples to which the Baykal EM-1 biopreparation was added. The oil content decreased more intensely (by 95–97%) in the soil samples containing earthworms as compared to the samples without them. The decomposition efficiency and the rate of oil hydrocarbons removal depended on the oil content and the presence or absence of the Baykal EM-1 biopreparation. The highest value (97–99%) was registered in the sample with the oil concentration of 40,000 mg/kg. The reproductive characteristics of the earthworms were shown to improve in the presence of Baykal EM-1. The obtained results are statistically important and demonstrate that microorganisms occurring in the Baykal EM-1 biopreparation have a positive effect on the earthworms’ survival, their reproductive potential, and capacity of hydrocarbon degradation.