View article

Dehalococcoides bacteria that produce catabolic vinyl chloride (VC) reductive dehalogenase enzymes have been implicated as a requirement for successful biological dechlorination of VC to ethene in groundwater systems. Therefore, the functional genes in Dehalococcoides that produce VC reductase (e.g., vcrA) may be important biomarkers for predicting and monitoring the performance of bioremediation systems treating chloroethenes via enhanced reductive dechlorination (ERD). As part of an ERD field demonstration, 45 groundwater samples were analyzed for vcrA using quantitative PCR. The demonstration delivered lactate continuously via groundwater recirculation over 201 days to an aquifer contaminated with cis-1,2-dichloroethene (cDCE, ∼150 μM) and VC (∼80 μM). Ethene (∼4 μM) and Dehalococcoides containing vcrA (average concentration of 4 × 10³ gene copies L⁻¹) were detected a priori in …