O. A. O'connor, L. Young
Oct 1, 1989
Citations
3
Influential Citations
157
Citations
Quality indicators
Journal
Environmental Toxicology and Chemistry
Abstract
Phenol, 2-chlorophenol, 2,4-dimethylphenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 3-methyl-4-chlorophenol (4-chloro-m-cresol) and 2-methyl-4,6-dinitrophenol (4,6-dinitro-o-cresol) were evaluated for their anaerobic biodegradability and toxicity to methanogenesis using two anaerobic bioassays, the biochemical methane potential (BMP) and the anaerobic toxicity assay (ATA). The BMP and ATA were used to evaluate the stoichiometric conversion of added substrate carbon to CO2 and CH4. Each substrate was the only added carbon source (20-200 mg/L) prepared in prereduced defined medium using a 10% (v/v) inoculum of municipal digester sludge. All concentrations of phenol and low concentrations (20 mg/L) of 2-chlorophenol, 2-nitrophenol, 4-nitrophenol and 2,4-dinitrophenol were completely mineralized. Higher concentrations of these same substrates (100 mg/L) and all concentrations of dimethylphenol, 3-methyl-4-chlorophenol and 2-methyl-4,6-dinitrophenol were observed to undergo no significant mineralization of added substrate and inhibited methanogenesis to varying degrees. Significant biotransformation of the monosubstituted nitrophenols occurred, resulting in the production of the corresponding aminophenols. Acclimation for most compounds took several days to weeks before methane could be detected in the substrate-amended cultures. Generally, the greater the substitution of the phenolic ring, the greater were the recalcitrance and toxicity of the substrate. The fate of these compounds can be significantly influenced by both their concentration and their residence time in anoxic environments.