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BIODEGRADATION OF A PAH MIXTURE BY NATIVE SUBSURFACE MICROBIOTA. (R828770C004)
Citation:
Brauner, J. S., M. A. Widdowson, J. T. Novak, AND N. G. Love. BIODEGRADATION OF A PAH MIXTURE BY NATIVE SUBSURFACE MICROBIOTA. (R828770C004). BIOREMEDIATION JOURNAL 6(1):9-24, (2002).
Description:
Laboratory microcosm studies were conducted to estimate biodegradation rates for a mixture of five polycyclic aromatic hydrocarbon compounds (PAHs). Static microcosms were assembled using soil samples from two locations collected at a No. 2 fuel oil-contaminated site in the Atlantic Coastal Plain of Virginia. In microcosms from one location, five PAHs (acenaphthene, fluorene, phenanthrene, pyrene, and benzo(b)fluoranthene) biodegraded at net first-order rates of 1.08, 1.45, 1.13, 1.11, and 1.12 yr-1, respectively. No observable lag period was noted and degradation in live microcosms ceased with the depletion of oxygen and sulfate after 125 days. In microcosms from a second location, net first-order biodegradation rates after an approximately 2-month lag period were 2.41, 3.28, and 2.98 yr-1 for fluorene, phenanthrene, and pyrene, respectively. Acenaphthene and benzo(b)fluoranthene mass loss rates in the live microcosms were not statistically different from mass loss rates in control microcosms. Stoichiometric mass balance calculations indicate that the dominant PAH mass loss mechanism was aerobic biodegradation, while abiotic losses (attributed to micropore diffusion and oxidative coupling) ranged from 15 to 33% and biotic losses from sulfate-reduction accounted for 7 to 10% of PAH mass loss. Stoichiometric equations that include biomass yield are presented for PAH oxidation under aerobic and sulfate-reducing conditions.
Author Keywords: PAH; biodegradation; natural attenuation; microcosm; sulfate-reduction