CLU-IN Home

U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Search Result

REMEDIATION OF CHLORINATED ETHENES IN FRACTURED SANDSTONE BY NATURAL AND ENHANCED BIOTIC AND ABIOTIC PROCESSES: A CRUSHED ROCK MICROCOSM STUDY
Yu, R., R.G. Andrachek, L.G. Lehmicke, and D.L. Freedman.
Science of the Total Environment 626:497-506(2018)

Most of the mass of TCE and cis-DCE at a fractured sandstone aquifer resides within the rock matrix. Strategies to restore groundwater to pre-existing conditions are severely limited by back diffusion. A microcosm study using crushed rock and groundwater from the site was performed to assess biostimulation and natural attenuation. Lactate, hydrogen release compound® (HRC), and emulsified vegetable oil (EVO) significantly increased the rate of TCE reduction to cis-DCE. Lactate also stimulated dechlorination of cis-DCE to VC and ethene, suggesting the presence of indigenous Dehalococcoides. Illumina sequencing and qPCR analyses suggest that reductive dechlorination of TCE to cis-DCE is mediated by Geobacter spp. while Dehalococcoides spp. perform reduction of cis-DCE to VC and ethene. The rate of VC reduction to ethene was much slower than the reduction of TCE to cis-DCE and cis-DCE to VC, indicating the indigenous Dehalococcoides perform the final step cometabolically and confirmed in enrichment cultures fed with only VC. Abiotic transformation of TCE and cis-DCE was observed based on accumulation of 14C-labeled products from 14C-TCE and 14C-cis-DCE. Based on accumulation rates for 14C-products in unamended microcosms, pseudo-first-order rates for abiotic transformation were 0.038/yr for TCE and 0.044/yr for cis-DCE, rates potentially sufficient to support natural attenuation in this diffusion-controlled system. See more on this study in R. Yu's dissertation at https://tigerprints.clemson.edu/all_dissertations/2019/.



The Technology Innovation News Survey welcomes your comments and suggestions, as well as information about errors for correction. Please contact Michael Adam of the U.S. EPA Office of Superfund Remediation and Technology Innovation at adam.michael@epa.gov or (703) 603-9915 with any comments, suggestions, or corrections.

Mention of non-EPA documents, presentations, or papers does not constitute a U.S. EPA endorsement of their contents, only an acknowledgment that they exist and may be relevant to the Technology Innovation News Survey audience.