Developmental hazard assessment with FETAX: Aerobic metabolites in bacterial transformation of naphthalene
- Univ. of Tennessee, Knoxville, TN (United States)
- Ashland Univ., OH (United States)
The underlying principle of bioremediation is the capability of microorganisms to biodegrade pollutants. When a contaminated site is biotreated, it is usually assumed that the disappearance of the pollutant means a reduction in the toxic effects of the contaminants. However, pollutants can undergo partial biodegradation or biotransformation. Microbial-mediated transformations play a critical role in the toxic effects of pollutants, as any alteration in structure can result in a change in physicochemical properties which influence toxicity. Therefore, a relevant question is; what is the toxicity of accumulative metabolites relative to the parent chemical? One class of chemicals that consistently appears at Superfund hazard waste sites is aromatic hydrocarbons. Studies of the aerobic bacterial metabolism of representative compounds, including benzene, naphthalene, and phenanthrene, have revealed similar oxidative pathways. Bacterial degradation of these aromatic hydrocarbons was initiated by the addition of two molecules of oxygen via a dioxygenase enzyme, with the resulting intermediate being converted to a catechol-like compound. From a biotransformation standpoint, one of the more thoroughly studied aromatic hydrocarbons has been naphthalene. Cerniglia (1984) has identified five major intermediates, 1,2-dihydroxynaphthalene, salicylaldehyde, salicylic acid, gentisic acid and catechol in the aerobic bacterial degradation of naphthalene. In vitro test systems such as the Frog Embryo Teratogenesis Assay - Xenopus (FETAX) provide a time- and resource-effective means for assessing developmental toxicity on a preliminary basis. FETAX is a 96-hr static-renewal system that uses early embryos of the frog Xenopus laevis. The purpose of this investigation was to determine the developmental hazard, using FETAX, of exposure to the model aromatic hydrocarbon, naphthalene, and it`s known major aerobic metabolites from bacterial transformation. 18 refs., 2 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 48006
- Journal Information:
- Bulletin of Environmental Contamination and Toxicology, Vol. 54, Issue 5; Other Information: PBD: May 1995
- Country of Publication:
- United States
- Language:
- English
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