Microbial degradation of acenapthene and napthalene under denitrification conditions in soil--water systems: Annual report, October 1987

Technical Report · Thu Oct 01 04:00:00 EDT 1987

DOI:https://doi.org/10.2172/6916930· OSTI ID:6916930

Mihelcic, J. R.; Luthy, R. G.

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 gram of soil. Under nitrate-excess conditions, both acenaphthene and naphthalene were degraded microbially from initial aqueous-phase concentrations of about one and several mg/l, respectively, to nondetectable levels (<0.01 mg/l) in time periods less than 9 weeks. Acclimation periods of 12 to 36 days were observed prior to the onset of microbial degradation in tests with soil not previously exposed to PAH, while acclimation periods were absent in tests with soil reserved from prior PAH degradation tests. It was judged that the apparent acclimation period resulted from the time for a small population of organisms capable of PAH degradation to attain sufficient densities to exhibit detectable PAH reduction. About 0.9 percent of the naturally occurring soil organic carbon could be mineralized under denitrification conditions, and this accounted for the greater proportion of the nitrate depletion. The mineralization of the labile fraction of the soil organic carbon via microbial denitrification occurred without an observed acclimation period, and was rapid compared to 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. The microbial degradation of the PAH compound depends on the interrelationships between: the desorption kinetics and the reversibility of desorption of sorbed compound from the soil, the concentration of PAH-degrading microorganisms, and the competing reaction for nitrate utilization via mineralization of the labile fraction of naturally occurring soil organic carbon. 44 refs., 10 figs.

• Research Organization: Carnegie-Mellon Univ., Pittsburgh, PA (USA). Dept. of Civil Engineering
• DOE Contract Number: AC21-84FC10619
• OSTI ID: 6916930
• Report Number(s): DOE/FC/10619-2519; ON: DE88001016
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
ACENAPHTHENE
AROMATICS
BIODEGRADATION
CHEMICAL REACTIONS
CONDENSED AROMATICS
DATA
DECOMPOSITION
DENITRIFICATION
DOCUMENT TYPES
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
MICROORGANISMS
MINERALIZATION
NAPHTHALENE
NITRATES
NITROGEN COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
POLYCYCLIC AROMATIC HYDROCARBONS
PROGRESS REPORT
SOILS
TIME DEPENDENCE