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Microbial degradation of acenaphthene and naphthalene under denitrification conditions in soil-water systems

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:6806592

This study examined the microbial degradation of acenaphthene and naphthalene under denitrification conditions at soil-to-water ratios of 1:25 and 1:50 with soil containing approximately 10/sup 5/ denitrifying organisms per g of soil. Under nitrate-excess conditions, both acenaphthene and naphthalene were degraded from initial aqueous-phase concentrations of about 1 and several mg/liter respectively, to nondetectable levels (<0.01 mg/liter) in less than 9 weeks. It was judged that the apparent acclimation period resulted from the time required for a small population of organisms capable of PAH degradation to attain sufficient densities to exhibit detectable PAH reduction, rather than being a result of enzyme induction, mutation, or use of preferential substrate. About 0.9% of the naturally occurring soil organic carbon could be mineralized under denitrification conditions, and this accounted for the greater proportion of the nitrate depletion. Mineralization of the labile fraction of the soil organic carbon via microbial denitrificaitonoccurred without an observed acclimation period and was rapid compared with PAH degradation. Under nitrate-limiting conditions the PAH compounds were stable owing to the depletion of nitrate via the more rapid process of soil organic carbon mineralization. Soil sorption tests showed at the initiation of a test that the total mass of PAH compound was divided in comparable proportions between solute in the aqueous phase and solute sorbed on the solid phase.

Research Organization:
Carnegie Mellon Univ., Pittsburgh, PA (USA)
DOE Contract Number:
AC21-84FC10619
OSTI ID:
6806592
Journal Information:
Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 54:5; ISSN AEMID
Country of Publication:
United States
Language:
English