Biological indicators of intrinsic bioremediation in a solvent-contaminated alluvium
- Merck and Co., Inc., Elkton, VA (United States). Environmental Projects Lab.
Historical activities at an industrial site resulted in contamination of the site subsurface. Although several contaminants were present, risk-analysis determined that benzene, toluene, and chlorobenzene were the primary compounds of concern. Extensive studies of site biota were undertaken to characterize the distribution of site microorganisms, contaminant degradative capacities, and the kinetic rates of removal of the compounds of concern. Total aerobic heterotrophs, facultative and aerotolerant anaerobes, benzene degraders, toluene degraders, and chlorobenzene degraders all had good to excellent correlations with volatile organic carbon concentrations. (Pearson correlation coefficients ranged from 0.74 to 0.99). Methane concentrations in the groundwater showed excellent correlation with benzene, toluene, and chlorobenzene concentration (Pearson correlation coefficient = 0.85). Site organisms were capable of mineralizing benzene, toluene, and chlorobenzene. Contaminant degradation rates were determined under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Experimentally derived kinetic rates of removal of the contaminants of concern ranged from 123.4 mg/l/hr for aerobic removal of benzene to 0.08 mg/l/hr for degradation of chlorobenzene under methanogenic conditions. Rates of oxygen consumption and contaminant removal indicated that site microorganisms have adapted to the concentrations and proportions of contaminants present in the groundwater. The results of these studies and of accompanying physical and chemical studies have led to the conclusion that substantial intrinsic bioremediation of groundwater contaminants is occurring.
- OSTI ID:
- 367473
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9640%%219
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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