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This content will become publicly available on March 22, 2018

Title: Natural Attenuation in Streambed Sediment Receiving Chlorinated Solvents from Underlying Fracture Networks

Contaminant discharge from fractured bedrock formations remains a remediation challenge. Here, we applied an integrated approach to assess the natural attenuation potential of sediment that forms the transition zone between upwelling groundwater from a chlorinated solvent-contaminated fractured bedrock aquifer and the receiving surface water. In situ measurements demonstrated that reductive dechlorination in the sediment attenuated chlorinated compounds before reaching the water column. Microcosms established with creek sediment or in situ incubated Bio-Sep beads degraded C 1-C 3 chlorinated solvents to less-chlorinated or innocuous products. Quantitative PCR and 16S rRNA gene amplicon sequencing revealed the abundance and spatial distribution of known dechlorinator biomarker genes within the creek sediment and demonstrated that multiple dechlorinator populations degrading chlorinatedC 1-C 3 alkanes and alkenes co-inhabit the sediment. Phylogenetic classification of bacterial and archaeal sequences indicated a relatively uniform distribution over spatial (300 m horizontally) scale, but Dehalococcoides and Dehalobacter were more abundant in deeper sediment, where 5.7 ± 0.4 × 10 5 and 5.4 ± 0.9 × 10 6 16S rRNA gene copies per g of sediment, respectively, were measured. The microbiological and hydrogeological characterization demonstrated that microbial processes at the fractured bedrock-sediment interface were crucial for preventing contaminants reaching the water column, emphasizingmore » the relevance of this critical zone environment for contaminant attenuation.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Civil and Environmental Engineering, Center for Environmental Biotechnology; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division and Joint Inst. for Biological Sciences (JIBS)
  2. Univ. of Tennessee, Knoxville, TN (United States). Center for Environmental Biotechnology; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division and Joint Inst. for Biological Sciences (JIBS); Chinese Academy of Sciences, Shenyang (China). Key Lab. of Pollution Ecology and Environmental Engineering, Inst. of Applied Ecology; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Microbiology
  3. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Microbiology
  4. Geosyntec Consultants, Knoxville, TN (United States)
  5. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Civil and Environmental Engineering, Center for Environmental Biotechnology; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division and Joint Inst. for Biological Sciences (JIBS); Univ. of Tennessee, Knoxville, TN (United States). Dept. of Microbiology
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 51; Journal Issue: 9; Journal ID: ISSN 0013-936X
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; USDoD
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES
OSTI Identifier:
1399394