Ecological and toxicological assessment of bioremediation of oil-contaminated soil

Under the conditions of the growing season, the monitoring of gray forest soil was carried out, which was polluted with Devonian oil at a concentration of 5% and 10% by weight of the soil. The content of oil products, the amount of hydrocarbon-oxidizing microorganisms, and phytotoxicity were determined. For remediation, a natural consortium of microorganisms-destructors (CMD) was used, consisting of three strains (Achromobacter insolitus A-102 (RCAM02108), A. xylosoxidans A-10 (RCAM02109) and Pseudomonas stutzeri P-1026 (RCAM02107) with titer (2.3-2.5)center dot 10(12) CFU/cm(3), as well as bentonite in the native (6 and 12 ton/ha) and nanoscale (0.6 and 1.2 ton/ha) forms as a sorbent. When comparing the indicators of hydrocarbon content in the dynamics, it was found that a high percentage of their utilization was noted for 45 days when used separately CMD and bentonite. The use of nanobentonite, as well as the integrated application of CMD with sorbents in native and nanoscale forms, accelerate this process by 15 days. The trend observed at 5% oil pollution is maintained with an increase in pollution to 10%. Ecological and toxicological analysis of oil-contaminated soil on the morphometric parameters of the test plant (Zea mays) allowed us to build a series of effectiveness of the introduced components: CMD > CMD + nanobentonite > CMD + bentonite. Bentonite and nanobentonite, sorbing hydrocarbons, are a source of mineral nutrition for autochthonous microflora. Nanobentonite at a dose less than 10 times contributes to an increase in the efficiency of cleaning contaminated soil compared to bentonite. The combined use of CMD and sorbent in native and nanoscale forms allows us to ensure the rate of destruction of oil pollution at a higher level compared to using each component separately.