Geochemical alteration of backfill FY98 status report

Buscheck, T.A.; Knauss, Kevin G.; Rosenberg, N.D.; Viani, B.E.

doi:10.2172/3020

Cited by 1 publication

(2 citation statements)

References 14 publications

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“…Site Description. The tests in this study were conducted in TCE-contaminated groundwater at a former chemical manufacturing plant in the San Francisco Bay area where TCE reductive dechlorination has been monitored in recent years ( , ). Tests were conducted in two distinct water-bearing zones, the A-zone and the C-zone.…”

Section: Methodsmentioning

confidence: 99%

“…Based on evidence that subsurface microorganisms are capable of degrading TCE under specific biogeochemical conditions, in situ bioremediation of TCE-contaminated groundwater is being investigated (). TCE degradation under methanogenic and sulfate-reducing conditions in laboratory () and field studies ( − ) has been reported. Anaerobic TCE degradation occurs by reductive dechlorination, a reaction in which hydrogen atoms sequentially replace chlorine substituents.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In Situ Anaerobic Transformation of Trichlorofluoroethene in Trichloroethene-Contaminated Groundwater

Hageman

Istok

Field

et al. 2001

Environ. Sci. Technol.

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Methods are needed to obtain in situ information on the transformation rates of trichloroethene (TCE), the most commonly detected organic groundwater contaminant. The objective of this research was to investigate the potential for determining TCE transformation rates in groundwater by measuring the transformation rate of its fluorinated surrogate, trichlorofluoroethene (TCFE). To explore this hypothesis, the in situ transport behavior, transformation pathway, and transformation rate of injected TCFE were determined in TCE-contaminated groundwater using single-well, push-pull tests. Although transport behavior varied between wells, TCFE, dichlorofluoroethene (DCFE), and TCE were transported similarly to each other. In the shallow water-bearing zone, TCFE was reductively dechlorinated to cis-DCFE, trans-DCFE, and (E)-1-chloro-2-fluoroethene (CFE), while co-injected TCE was concurrently transformed to cis-dichloroethene (DCE), trans-DCE, 1,1-DCE, and a trace amount of chloroethene (CE). With added formate and the injected TCFE concentration being a factor of 20 higher than that of TCE, the TCFE transformation rate ranged from 0.053 to 0.30 mumol/L-day, while that of TCE ranged from 0.009 to 0.012 mumol/L-day. Without added formate, the TCFE transformation rate decreased to 0.036 mumol/L-day. In the deeper water-bearing zone, TCFE transformation occurred only after a lag time of 55 days with added formate. No TCFE transformation occurred in groundwater that had not previously been exposed to TCE. The potential applicability for TCFE as an in situ transport and transformation surrogate for TCE was demonstrated.

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Section: Methodsmentioning

confidence: 99%