MICROBIAL-DEGRADATION OF CRUDE-OIL IN MARINE ENVIRONMENTS TESTED IN AFLASK EXPERIMENT

Thirteen different bioremediation products were evaluated for their ef fectiveness in biodegrading petroleum hydrocarbons. All 13 products te sted in this experiment were listed on the NCP product schedule. Of th ese 13 products, 12 were bioaugmentation agents and one was a biostimu lation agent. All the products were tested for toxicity levels initial ly, using standardized protocols. The products were sampled and analyz ed three times over a 28-day period for most-probable number (MPN) of hydrocarbon degraders and total petroleum hydrocarbon as separate frac tions. A subsample was analyzed for MPN, and the rest of the sample wa s extracted and fractionated in total saturated petroleum hydrocarbons (TsPH) and total aromatic petroleum hydrocarbons (TarPH). This experi ment revealed that the petroleum hydrocarbons were biodegraded to an e xtent significantly greater than that achieved by the naturally occurr ing microorganisms. After 28 days, some products reduced the TsPH frac tion to 60% of its initial weight and the TarPH fraction to 65%. Three of the 13 products tested enhanced microbial degradation of the petro leum to a degree significantly better than the nutrient control treatm ents. Of these three products, only one showed a toxicity level below that of the control treatment. (C) 1997 Elsevier Science Ltd.