Web Release Date: July 30,
Reductive Dechlorination of the Vinyl Chloride Surrogate Chlorofluoroethene in TCE-Contaminated Groundwater
and
Department of Chemistry, Department of Environmental and Molecular Toxicology, and Department of Civil, Construction, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331
Received for review August 31, 2004
Revised manuscript received May 31, 2005
Accepted June 13, 2005
Abstract:
At many trichloroethene (TCE)-contaminated field sites,
microbial transformation of TCE results in the accumulation
of vinyl chloride (VC), a known carcinogen and neurotoxin.
Quantitative tools are needed to determine the in situ
rates of VC transformation to ethene in contaminated
groundwater. For this study, E-/Z-chlorofluoroethene
(E-/Z-CFE) was evaluated as a surrogate for VC in laboratory
microcosm and field push-pull tests. Single-well push-pull tests were conducted at a TCE-contaminated field site
by injecting E-/Z-CFE and monitoring for the formation of
fluoroethene (FE) over a period of up to 80 days. The rates
for VC transformation to ethene and E-CFE transformation
to FE were within a factor of 2.7 for laboratory microcosm
systems and all preferentially transformed E-CFE over Z-CFE.
In the field, the in situ rates of FE production from
injected E-CFE ranged from 0.0018 to 1.15 
M/day, while
the in situ rates of E-CFE disappearance ranged from 0.17
to 0.99 M/day. No significant Z-CFE transformation was
observed in field tests, which indicated preferential utilization
of E-CFE over Z-CFE under in situ field conditions. The
results of this study indicate E-CFE as a potential surrogate
for estimating the in situ rates of VC transformation.
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