Inhibitory effect of 5- and 6-ring PAHs on pyrene mineralization by a mixed enrichment culture
- Environmental Protection Agency, Athens, GA (United States)
This research investigates the mineralization of pyrene in mixtures of PAHs to identify potential synergistic or antagonistic interactions that affect the degradation of individual compounds. Mineralization of {sup 14}C pyrene (25 RM) by a mixed enrichment culture was studied in systems containing mixtures of 5- and 6-ring PAHs in minimal salts medium (MSM). In the absence of the High Molecular Weight (HMW)-PAHs, the culture mineralized 62% of the added pyrene. Addition of an equal mixture of benzo(a)pyrene, dibenzanthracene, and benzo(g,h,i)peryiene (25 {micro}M total concentration) reduced pyrene mineralization to 25% after a 9-day lag phase. An increase on the molar concentration of the HMW-PAH mixture to 75 and 125 {micro}M decreased pyrene mineralization to 9.2 and 1%, respectively. Results from treatments containing individual (25 {micro}M each), or pairs of the HMW-compounds demonstrated that none of the three individual compounds caused a significant reduction in the extent of pyrene mineralization. However, the combination of benzo(a)pyrene and benzanthracene significantly inhibited pyrene activity. In addition, the presence of both benzo(a)pyrene and benzo(g,h,i)peryiene reduced mineralization by almost 23%. Determination of bacterial density by epifluorescence microscopy showed that mineralization of pyrene coincides with growth of the bacterial culture; presence of the 5- and 6-ring PAHs delayed growth with a concurrent inhibition of mineralization. When growth resumes, the inhibitory effect is reduced. A decrease of pyrene inhibition was also noted when MSM was replaced with sediment extract, or when sediment (1 {micro}g/ml) was added to the medium. These results suggest a synergistic inhibitory effect by combinations of specific HMW-PAHs rather than inhibition by individual compounds of the mixture on both the growth of the bacterial culture and the extent of pyrene mineralization.
- OSTI ID:
- 218463
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9619%%184
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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