Photo and biodegradation of pyrene and benzo(a)pyrene in a model of the near surface environment
A statistical model that describes the photodegradation of two polycyclic aromatic hydrocarbons (PAH), pyrene and benzo(a)pyrene, in a model of the near surface aqueous environment containing suspended silica (0-18 mg/l) and humic materials (0-0.2 AU) was developed. Literature describing source and occurrence, physicochemical properties, and toxicity of the two PAH relating to the research was reviewed. Environmental parameters affecting fate and transport of the two PAH were identified using the exposure analysis model EXAMS using input from calculated or literature values of chemical properties. Molar absorptivities of pyrene and benzo(a)pyrene in an aqueous environment at concentrations near their solubility limit were estimated in the 336- to 400-nm wavelength region. Actinometer corrected direct and indirect photolysis rates of the two PAH at concentrations near their solubility limits were determined, as well as quantum yields which varied over a sixfold range for benzo(a)pyrene and an eightfold range for pyrene. Effects of potential sensitizers, pH, suspended sediment, or humic materials are attributed to photolysis rate statistically. For pyrene, humic material was the most important parameter affecting rate of photodegradation; humic material was most important for benzo(a)pyrene. Direct photodegradation products were characterized using gas chromatography/mass spectroscopy. Fifteen baseline resolved isomers of benzo(a)pyrene photodegradation products as well as three other classes of products were observed. Similar results were observed for pyrene. Respiration of microbes given parent PAH or photolyzed PAH as sole carbon source was measured as an indicator of biodegradation. Photodegraded pyrene increased respiration of microbes. A difference between respiration of microbes utilizing benzo(a)pyrene as sole carbon source versus respiration of microbes utilizing photolysis products of benzo(a)pyrene could not be supported by statistical analysis.
- Research Organization:
- Alabama Univ., Birmingham, AL (United States)
- OSTI ID:
- 7161027
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BENZOPYRENE
BIODEGRADATION
PHOTOLYSIS
PYRENE
AQUATIC ECOSYSTEMS
BIOLOGICAL PATHWAYS
ENVIRONMENTAL TRANSPORT
HUMIC ACIDS
MICROORGANISMS
STATISTICAL MODELS
AROMATICS
CHEMICAL REACTIONS
CONDENSED AROMATICS
DECOMPOSITION
ECOSYSTEMS
HYDROCARBONS
MASS TRANSFER
MATHEMATICAL MODELS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)