Polynuclear aromatic hydrocarbon metabolism in soils: Relationship to soil characteristics and preexposure
- Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Environmental Sciences and Engineering
The fate of radiolabeled ([{sup 14}C]) phenanthrene, pyrene, benz[a]anthracene, chrysene, and benzo[a]pyrene was examined in five soils, four of which had previous exposure to polycyclic aromatic hydrocarbons (PAHs). The soils and [{sup 14}]PAHs studied represent a range of characteristics (fraction of soil organic carbon [f{sub oc}] and PAH solubility) that can potentially impact contaminant fate. Fates of [{sup 14}C]PAHs examined in slurry microcosms included mineralization, production of water-soluble metabolites and their polarity, cellular incorporation, and the association of [{sup 14}C]PAHs with soils, all compared to an abiotic control. The soils all contained active heterotrophic communities and the contaminated soils had sizable populations of PAH-degrading microorganisms, measured by the [{sup 14}C]-most probable number assay. All [{sup 14}C]PAHs, except [{sup 14}C]benzo[a]pyrene, were readily mineralized in most of the preexposed soils, whereas in the uncontaminated soil, less than 5% of each [{sup 14}C]PAH was mineralized. In the adapted soils, mineralization, after 8 weeks of incubation, accounted for 30 to 60% of [{sup 14}C]phenanthrene, 10 to 55% of [{sup 14}C]pyrene, 5 to 40% of [{sup 14}C]benz[a]anthracene, 10 to 50% of [{sup 14}C]chrysene, and 2 to 9% of [{sup 14}C]benzo[a]pyrene added to the microcosms. Metabolite production and cellular incorporation usually accounted for less than 10% of the added [{sup 14}C]PAH. The fate of PAHs was usually not related to measurements of microbial community size, characteristics of the PAH (water solubility and K{sub ow}), and many characteristics of soils (soil f{sub oc} and PAH concentration). The fraction of silt and clay in the soils for each soil-PAH combination, however, was negatively related to the extent of added [{sup 14}C]PAH mineralized and the amount solvent extractable from the soil, and positively related to the amount of [{sup 14}C]PAH remaining in soils after extraction.
- Sponsoring Organization:
- National Inst. of Environmental Health Sciences, Research Triangle Park, NC (United States)
- OSTI ID:
- 514516
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 16, Issue 4; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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