Anoxic biotransformation of 2,4-dinitrotoluene by denitrifying enrichment cultures
The cometabolic biotransformation of 2,4-dinitrotoluene (DNT) under nitrogen reducing conditions by enrichment cultures using ethanol as the main source of carbon and energy was studied. Two microbial cultures were enriched from two different sources representing environments with and without previous exposure to DNT: the wastewater treatment system at the Radford Army Ammunition Plant in Radford, VA, and the municipal wastewater treatment plant in Urbana, IL. DNT was completely biotransformed. by both enrichment cultures. However, experiments with uniformly labeled [14C]-DNT demonstrated that no significant mineralization occurred. Losses by volatilization accounted for 9 and 7% of the original {sup 14}C-tracer in the unacclimated and acclimated cultures, respectively. The formation of insoluble materials was significant, with 41% of the tracer associated with this fraction in the unacclimated and 33% in the acclimated cultures. Most of the soluble metabolites were hydrophilic in the cultures from the unacclimated source. These metabolites were characterized according to their charge by HPLC and ion pairing chromatography. In the acclimated culture, 60% of the soluble metabolites were classified as hydrophobic materials. GC-MS analyses of this fraction revealed the presence of 2- and 4- mononitrotoluenes, 6-nitroindazole, acetylaminotoluene, and 4-acetylamino-2- nitrotoluene. These results indicate the inadequacy of setting a discharge limit only for DNT, since a number of the metabolites formed may also pose a significant toxicological hazard.
- OSTI ID:
- 416906
- Report Number(s):
- CONF-951023-; TRN: 96:005001-0063
- Resource Relation:
- Conference: 68. annual conference and exposition of the Water Environment Federation, Miami Beach, FL (United States), 21-25 Oct 1995; Other Information: PBD: 1996; Related Information: Is Part Of WEFTEC `95: 68th annual conference & exposition; PB: 498 p.
- Country of Publication:
- United States
- Language:
- English
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