title: Microcosm and in situ field studies of enhanced biotransformation of trichloroethylene by phenol-utilizing microorganisms.
abstract: The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms amended with phenol or toulene were equally effective in removing c-DCE (> 90%) followed by TCE (60 to 70%), while the microcosm fed methane was most effective in removing t-DCE (> 90%). The microcosm fed ammonia was the least effective. None of the microcosms effectively degraded 1,1,1-trichloroethane. At the Moffett Field groundwater test site, in situ removal of c-DCE and TCE coincided with biostimulation through phenol and oxygen injection and utilization, with c-DCE removed more rapidly than TCE. Greater TCE and c-DCE removal was observed when the phenol concentration was increased. Over 90% removal of c-DCE and TCE was observed in the 2-m biostimulated zone. This compares with 40 to 50% removal of c-DCE and 15 to 25% removal of TCE achieved by methane-grown microorganisms previously evaluated in an adjacent in situ test zone. The in situ removal with phenol-grown microorganisms agrees qualitatively with the microcosm studies, with the rates and extents of removal ranked as follows: c-DCE > TCE > t-DCE. These studies demonstrate the potential for in situ TCE bioremediation using microorganisms grown on phenol.
authors.affiliation: Department of Civil Engineering, Stanford University, California 94305-4020.
authors.forename: G D
authors.initials: GD
authors.lastname: Hopkins
authors.forename: L
authors.initials: L
authors.lastname: Semprini
authors.forename: P L
authors.initials: PL
authors.lastname: McCarty
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media / Q000737:chemistry; D004000:Dichloroethylenes / Q000378:metabolism*; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism; D010101:Oxygen Consumption; D019800:Phenol; D010636:Phenols / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D003470:Culture Media; D004000:Dichloroethylenes; D006843:Hydrocarbons, Chlorinated; D010636:Phenols; D014241:Trichloroethylene; D019800:Phenol