This demonstration had three specific objectives. The first objective was to demonstrate the utility of quantitative proteomics (qProt) to measure the absolute abundance of Dhc reductive dechlorination biomarker proteins in laboratory-controlled microcosms with various Dhc cell titers. Contaminant concentration and ethene measurements over time were used to determine cis-DCE and vinyl chloride (VC) reductive dechlorination rates. The second objective was to correlate observed degradation rates with Dhc biomarker gene and protein abundances. The successful completion of objectives 1 and 2 led to a go/no-go decision point before conducting demonstration/validation efforts of the qProt approach at military sites impacted with chlorinated ethenes.