Restoration of Oil-Contaminated Soils in Mountain Tundra (Murmansk Region, Russia)

The efficiency of different bioremediation methods (loosening, application of mineral and organic fertilizers) for soils contaminated with oil products was evaluated in the mountain tundra (Kascama Mountain) of Pechenga district, Murmansk region. The results showed decrease of hydrocarbon content in soil by 75-79%; increase of humus organic carbon content up to 81-86%, mobile phosphates up to 11.54-15.36 mg/100 g, and nitrogen up to 0.6%. The combined use of mineral and organic fertilizers yielded the best results. However, the content of water-soluble carbon decreased as a result of increased microbial activity. Bioremediation activated bacterial growth in general and particularly, hydrocarbon-oxidizing bacteria (HOB). Soil loosening and the use of mineral and organic fertilizers increased the proportion of HOB in the microbial community. The maximum increase of biological activity was noted after implementation both mineral fertilizer and Bamil bio fertilizer. The integral index of the soil biological state (IISBS) and biological activity of the soil (IIBAS) as well as enzymatic activity showed that the combined use of mineral fertilizers and Bamil bio fertilizer provide the maximum positive effect on the biological state of contaminated soils, thereby the indices increased by 5 and 8 times, respectively. Despite the adverse working conditions (climate of the area, distant location on the mountain slopes and a high degree of soil degradation), successful remediation measures are possible using the bioremediation techniques.