Enhanced Reductive Dechlorination of Chlorinated Aliphatic Hydrocarbons: Molecular and Biochemical Analyses

Background/need – Chloroalkenes are widespread groundwater contaminants for which enhanced reductive dechlorination (ERD) via electron donor augmentation can serve as an effective, in situ bioremedial strategy. A major goal of ERD is to stimulate late stage dechlorination reactions, which are needed to prevent accumulation of toxic intermediates. Establishment of methanogenic conditions is important for the onset and support of late stage dechlorination processes that involve reduction of dichloroethene (DCE) to vinyl chloride (VC), and VC reduction to the non-toxic end-point compound, ethene. However, little is known about the composition of microbial communities that are active in late-stage dechlorination. Elucidating the structure and function of microbial communities associated in the field with late stage dechlorination reactions could help establish a mechanistic foundation that would advance the science of ERD, and consequently enhance the effectiveness with which the process might be applied and managed.

Objectives – 1) Delineate the microbial community dynamics induced by soluble carbohydrate augmentation in field samples and during progress in ERD. 2) Elucidate the composition of communities that effect complete dechlorination of CAH in field samples.