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OUR EVOLVING UNDERSTANDING OF THE ANAEROBIC BIODEGRADATION OF BTEX COMPOUNDS IN GROUND WATER (ABSTRACT ONLY)
Citation:
WILSON, J. T. OUR EVOLVING UNDERSTANDING OF THE ANAEROBIC BIODEGRADATION OF BTEX COMPOUNDS IN GROUND WATER (ABSTRACT ONLY). In Proceedings, Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, CA, May 22 - 25, 2006. Battelle Press, Columbus, OH, M-04, ISBN1574771574, (2006).
Impact/Purpose:
to inform public
Description:
In the early 1980s the ground water community became aware of widespread contamination of groundwater by benzene, toluene, ethylbenzene and xylenes (BTEX compounds) from gasoline spills from underground storage tanks. This new awareness was made possible by the introduction of the purge and trap method to analyze volatile organic compounds in water. This was the first method for analysis of BTEX compounds that was both sensitive and affordable. Conventional wisdom at the time held that it was necessary to have molecular oxygen to biologically degrade aromatic hydrocarbons. The resonance energy of the phi bond in aromatic hydrocarbons precluded any anaerobic mechanism for biodegradation. This had been “confirmed and validated” by the failure to enrich organisms that degraded BTEX compounds in short term enrichment cultures. The first clue that the conventional wisdom might be wrong was the accumulation of high concentrations of methane in certain gasoline spill sites, and the accumulation of partially oxidized compounds such as organic acids and aldehydes. The first data suggesting that BTEX compounds could be degraded in anaerobic ground water was produced by chemists and geologists that had never been taught that BTEX compounds could not be degraded in anaerobic systems, they did not know any better, and they went ahead and did the experiments anyway. Classically trained microbiologists were used to working with organisms that grew rapidly. As a consequence, they rarely incubated their enrichments more than a few weeks. As a result of their impatience, the microbiologists failed to detect anaerobic degradation of BTEX compounds in their laboratory studies. The chemists and geologists incubated their microcosm studies for many weeks and months, and as a consequence they were able to detect rates of anaerobic biodegradation in contaminated sediment that were slow as far as laboratory systems went, but were fast enough to have environmental significance.
URLs/Downloads:
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OUR EVOLVING UNDERSTANDING OF THE ANAEROBIC BIODEGRADATION OF BTEX, ETC. (PDF, NA pp, 20 KB, about PDF)