Application of Nucleic Acid-Based Tools for Monitoring Monitored Natural Attenuation (MNA), Biostimulation and Bioaugmentation at Chlorinated Solvent Sites

Abstract : Successful anaerobic bioremediation at chlorinated solvent sites relies on the presence of bacteria, such as Dehalococcoides (Dhc), capable of organohalide respiration (i.e., respiratory reductive dechlorination or [de]chlororespiration). Nucleic acid-based assays like the quantitative real-time polymerase chain reaction (qPCR) technique detect and enumerate Dhc in soil or groundwater samples by targeting Dhc-specific biomarker genes, including the 16S rRNA gene and the tceA, bvcA, and vcrA reductive dechlorinase (RDase) genes implicated in chlorinated ethene reductive dechlorination. The results of nucleic acid-based tests, like the qPCR approach, are expected to assist site managers and practitioners to identify sites where implementation of long-term monitored natural attenuation (MNA) will be effective; where biostimulation will achieve complete dechlorination without DCE/VC stall; and where bioaugmentation is required.