Biotransformation of selected organic pollutants in ground water

Abstract

Widespread contamination of ground water by a variety of synthetic organic compounds has created a need for information about the biotransformation of these contaminants in aquifers and associated regions of the unsaturated subsurface. Uncontaminated samples of the subsurface were taken from positions immediately above and below the water table at Pickett, OK, and Fort Polk, LA. Selected organic pollutants were added aseptically to the samples at an initial concentration of 1 mg/liter water. No degradation of 1,1,1-trichloroethane, chloroform, or 1,1-dichloroethane was detected in any of the samples. Toluene and styrene was degraded slowly in samples from both positions at both sites. Chlorobenzene was degraded in samples from both positions at Pickett, but no degradation was detected in samples from Fort Polk. There was no detectable degradation of these three compounds in autoclaved samples. Tri- and tetrachloroethylene was degraded very slowly in some of the samples. These rates, however, were the same magnitude as published rates of chemical hydrolysis. Microbes in the deeper subsurface can degrade some, but not all, of the organic pollutants commonly encountered in ground water. 26 references, 3 figures, 2 tables.