Microbial degradation of selected aromatic compounds in a hazardous waste site
Lee, Michael Donald
Ward, C. H.
Master of Science
Microbial degradation of five aromatic compounds was followed in aseptically-taken subsurface soil samples and ground water samples from the vicinity of a pit used to dispose the waste from a wood creosoting plant. The five compounds--anthracene, dibenzofuran, fluorene, naphthalene, and pentachlorophenol--were contaminants found in the soil and ground water. There was degradation of the selected compounds in the subsurface soil, although the importance of biological activity was not conclusively shown. Microbes in the ground water were able to biodegrade all five of the compounds with naphthalene, dibenzofuran, and fluorene being degraded most rapidly. Faster rates of degradation were noted for the more contaminated wells which had microbial populations that were adapted to the compounds. The presence in both ground water and soil samples of microbes which could utilize the aromatic compounds (except pentachlorophenol) as sole carbon sources was also demonstrated. Their numbers decreased with depth in the soil and increased with levels of contamination in the ground water. Total microbial counts on soil samples from 15 and 24 ft (water table) below the surface were about the same, but lower than that in the surface samples.