Metabolite formation and toxicity measurements in evaluating bioremediation of a jet-fuel-contaminated aquifer.
The metabolic capabilities of subsurface, jet-fuel-contaminated, aquifer microbial communities were characterized using an ecological approach to biotreatment assessment. A multifaceted experimental design was used that incorporated quantification of metabolite formation and toxicity screening along with the typical microbial activity measurements and pollutant degradation measurements used for assessing bioremediation potential. For select experiments, dissolved oxygen levels and pH in microcosm systems were also monitored. Results suggest that a sizable, metabolically active microbial community exists in both contaminated and uncontaminated areas of the study site. Time course metabolism analyses indicated that the microbial communities were capable of degrading all three test compounds (amino acids, decane, and toluene) without any apparent adaptation period. Measurements of mineralization, cellular uptake, and metabolite formation indicated that metabolite formation was the predominant fate of the target pollutants in the microcosms. The results of toxicity screening time courses indicated that under oxygen-limiting conditions, the potential for the accumulation of toxic, acidic metabolites that could adversely affect the rates and extent of bioremediation existed. The experimental results indicate that the microbial communities at the site possess the metabolic potential for in situ biodegradation of the jet fuel. Care must be taken in the design of an in situ biodegradation treatment system (for this site and perhaps other petroleum-contaminated aquifers) to avoid the development of microaerophilic or oxygen-depleted zones, which could result in possible self-poisoning owing to acidic metabolite accumulation.
Long
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Department of Civil and Environmental Engineering, University of Massachusetts, Amherst 01003, USA. long@ecs.umass.edu
Aelion
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D001359:Aviation; D001673:Biodegradation, Environmental; D003666:Decontamination; D004784:Environmental Monitoring; D005069:Evaluation Studies as Topic; D005579:Fossil Fuels; D018675:Toxicity Tests; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D005579:Fossil Fuels; D014874:Water Pollutants, Chemical