The Efficiency of Rhizosphere Bioremediation with Azospirillum sp. and Pseudomonas stutzeri in Soils Freshly Contaminated with PAHs and Diesel Fuel
Anna Gałązka, Maria Król, Andrzej Perzyński
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Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation – State Research Institute,
Czartoryskich 8, 24-100 Puławy, Poland
Pol. J. Environ. Stud. 2012;21(2):345–353
In this study the effects of meadow fescue (Festuca pratensis) inoculated (I+) and non-inoculated (I-) by diazothrophic species of bacteria (Azospirillum spp. and Pseudomonas stutzeri) on the degradation of polycyclic aromatic hydrocarbons in soils freshly contaminated with a mixture of PAHs and diesel fuel was investigated. Plants were grown in three different soils (chernozem, rendzina, lessives) for 4 weeks and unplanted soils considered as control. At the end of the experiment, physical properties of soils, dry masses of plants, and Σ 15PAH contents were measured in the soils. The results demonstrated that I (+) plants contained more root and shoot biomass than I (-) plants. Planting stimulated the bioremediation process in contaminated soils. The differences in concentration between the inoculated or non-inoculated soils indicate that the presence of plant roots, in addition to the passage of time, contributes, to reduction in the bioavailability of a mixture of PAHs and diesel fuel. The choice of soils, contamination, and inoculation has a significant effect of PAH degradation (mixture 1: in chernozem 24.8-59.7%, in rendzina 15.4-41.4%, in lessives 48.4-71,4%). It was revealed that they were more degraded in the rhizosphere of (I+) plants compared to I (-) ones. Obtained results suggests that inoculation of plants with Azospirillum spp. and P. stutzeri looks promising as a low-cost treatment method for PAH-contaminated soil.