Remediation of Oil Contaminated Soil by Petruleum Decomposing Soil Indigenous Microorganisms.

The results indicated that the effects of bacteria, pollution and also their interactive effects on shoot fresh weight, as well the effects of pollution, interaction of bacteria with pollution on shoot dry weight and also the effect of pollution on fresh and dry weight of root were significant. Pollution decreased the fresh and dry weight of root and shoot, while inoculation of bacteria improved root and shoot weight, due to elimination of pollutant. The effects of all treatments on pollutant concentration were significant. Planting and bacteria inoculation decreased pollutant concentration in soil significantly. Bacteria inoculation was more efficient than plant sowing from aspect of pollutant decreasing, and plant did not increase bacteria efficiency significantly, thus the difference between plant and plant bacteria treatments was not significant. In experiment 5, the ability of five strains of Pseudomonas namely R169, R108, P12, P9, R4 to grow in heavy metal and oil contamination and also their effect on growth of wheat in heavy metal and oil contamination condition was evaluated. A greenhouse experiment was conducted in completely randomized design with factorial arrangement with three varieties of wheat and six bacterial treatments (five strains and an un-inoculated control) in four replications. Results revealed that some strains were tolerant to heavy metals and oil and were able to promote seed germination and root lenght. In greenhouse condition, inoculation with bacterial strains significantly increased some growth indices and yield of wheat. In experiment 6, the efficiency of some pseudomonads strain that were capable of producing the ACC-deaminase enzyme, on bioremediation ability of corn, barely, and canola plants in oil polluted soil condition was carried out as individual greenhouse experiment in a completely radomized design, including five treatments with inoculating bacteria; Pseudomonas putida strain 4 ،Pseudomonas putida strain 108 ،Pseudomonas fluorescens strain169 ،Pseudomonas fluorescens strain12 ، Pseudomonas fluorescens strain9, and the control treatment without the inoculation, which were replicated four times. In all the carried out individual experiments, the effect of the studied strains on the plant growth indexes of the corn, barely and canola was significant at the α =1% level. In the corn and barely case, the P12 strain had the most effect on the plant growth indices of these plants in the oil polluted soils. In the canola case, the most effective strain, was the R169, but there was no significant with the other strains and including P12 strain. Over all, the P12 strain could be introduced for increasing plant growth in the oil polluted soil conditions. We also concluded that, in the case of removing polycyclic aromatic hydrocarbons (PAHs) and also in no plant conditions the P12 and P9 strains, in the corn and canola growth conditions the R169 and R108 strains, and in the barely case the P9 strain had the most effect. In experiment 7, in order to investigation the mycorrhizal efficiency to increase plant ability in mineral nutrient and heavy metal uptake from a contaminated soil with a high level of Cr, Ni and Cd, a greenhouse experiment with two hyper accumulatore plants (sunflower and corn) and 4 species of mycorrhizal fungi (Glomus mosseae , Glomus intraradices ,Glomus etunicatum and Glomus sp.) and one treatment without fungi as control, with 5 replications was conducted. Results showed that mycorrhizal inoculation in two plants, sunflower and corn by increasing mycorrhizal colonization enhanced aerial part growth of plant and also macro and micro nutrient uptake.T4 treatment, including G. mosseae and G. intraradices in corn growth had the highest capacity for Cd, Ni and Cr uptake from the soil. In sunflower this treatment increased only Cd and Ni uptake meaningfully. Finally if we want to use these two plants for phytoremediation, the use of these two fungi will be proposed. Key words: Bioremediation, Phytoremediation, Microbial remediation, Phenantherene, Toluene, Gas oil, oil decomposing bacteria, Biosurfactant, Soil moisture regims, oil contaminated soils, Polycyclic Aromatic Hydrocarbon compounds (PAHS), Fluorescent pseudomonads, Wheat, Canola, Corn, Sunflower, Mycorrhizal symbiosis, ACC-deaminase enzyme, Heavy metals