Changes in the mutagenicity of petroleum products undergoing bioremediation
- EPA, Research Triangle Park, NC (United States)
As EPA, industry, and others promote the use of bioremediation as a treatment alternative for environmental contamination, the health risks of such cleanup efforts must be assessed. Conversions of toxic constituents to metabolic intermediates and byproducts can result in fluctuations in toxicity over time. We have examined this process by studying the microbial degradation of petroleum products in the field and in the laboratory. For the field study, we evaluated 2 accidental releases (a coastal oil spill and a refinery leak) in which biodegradation was achieved by accelerating the proliferation of indigenous soil microbes through application of nutrient formulations. Soil samples were collected before, during, and after in situ treatment, and organics were extracted from the soils by sonication with dichloromethane (DCM). The extracts were tested for mutagenicity using the spiral Salmonella assay. Results indicated that the mutagenicity of the oil-impacted beaches depended on soil composition, nutrient formulation, and natural removal processes such as wave action. The mutagenicity of the refinery fuel-impacted soils was related to depth of collection, water table location, and levels of BTEX contamination. For the laboratory study, we evaluated the bio-degradation of 3 crude oils by 2 species of fungi combined in flasks of mineral salts. Flasks were incubated at 30{degrees}C for up to one month, and contents were extracted with DCM at 2-day intervals and tested for mutagenic activity. An oil that was highly mutagenic became nonmutagenid in as few as 5-6 days of treatment, while a nonmutagenic oil became mutagenic over time.
- OSTI ID:
- 115128
- Report Number(s):
- CONF-9503160--
- Journal Information:
- Environmental and Molecular Mutagenesis, Journal Name: Environmental and Molecular Mutagenesis Journal Issue: Suppl.25 Vol. 25; ISSN 0893-6692; ISSN EMMUEG
- Country of Publication:
- United States
- Language:
- English
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