Limited effect of introduced microbial inoculants in the bioremediation of petroleum-contaminated soils
石油污染土壤生物修复中外源微生物的影响

Bacteria and fungi were isolated from a long-term petroleum-contaminated site and their potential to enhance the degradation of mineral oil and 16 polycyclic aromatic hydrocarbons (PAHs) during the bioremediation of diesel-contaminated soil was estimated by means of outdoor pot cultivation. The factors adjusted included contamination level, bacterial inoculation volume, fungal inoculation volume, and manure addition. After one growth season (about 150 days) the initial introduced bacterial and fungal inoculants had no influence on the number of total bacteria, total fungi, PAH-degrading bacteria, and PAH-degrading fungi in each treatment ( p >0.05). Manure addition significantly promoted the increase of soil microorganisms, including total bacteria, total fungi, and PAH-degrading bacteria ( p <0.05). At the end of the test, the removal ratios were 58.8% to 88.3% for mineral oil, and 91.7% to 97.8% for the 16 PAHs listed by the US EPA. No advantages to the degradation of mineral oil and PAHs were achieved by the inoculation of either introduced bacteria or fungi, thus indicating their limited ability to compete in degrading contaminants.