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Title: Bacterial Community Dynamics in Dichloromethane-Contaminated Groundwater Undergoing Natural Attenuation

The uncontrolled release of the industrial solvent methylene chloride, also known as dichloromethane (DCM), has resulted in widespread groundwater contamination in the United States. Here we investigate the role of groundwater bacterial communities in the natural attenuation of DCM at an undisclosed manufacturing site in New Jersey. Here, we investigate the bacterial community structure of groundwater samples differentially contaminated with DCM to better understand the biodegradation potential of these autochthonous bacterial communities. Bacterial community analysis was completed using high-throughput sequencing of the 16S rRNA gene of groundwater samples (n = 26) with DCM contamination ranging from 0.89 to 9,800,000 μg/L. Significant DCM concentration-driven shifts in overall bacterial community structure were identified between samples, including an increase in the abundance of Firmicutes within the most contaminated samples. And across all samples, a total of 6,134 unique operational taxonomic units (OTUs) were identified, with 16 taxa having strong correlations with increased DCM concentration. Putative DCM degraders such as Pseudomonas, Dehalobacterium and Desulfovibrio were present within groundwater across all levels of DCM contamination. Interestingly, each of these taxa dominated specific DCM contamination ranges respectively. Potential DCM degrading lineages yet to be cited specifically as a DCM degrading organisms, such as the Desulfosporosinus, thrivedmore » within the most heavily contaminated groundwater samples. Co-occurrence network analysis revealed aerobic and anaerobic bacterial taxa with DCM-degrading potential were present at the study site. Our 16S rRNA gene survey serves as the first in situ bacterial community assessment of contaminated groundwater harboring DCM concentrations ranging over seven orders of magnitude. Diversity analyses revealed known as well as potentially novel DCM degrading taxa within defined DCM concentration ranges, indicating niche-specific responses of these autochthonous populations. Altogether, our findings suggest that monitored natural attenuation is an appropriate remediation strategy for DCM contamination, and that high-throughput sequencing technologies are a robust method for assessing the potential role of biodegrading bacterial assemblages in the apparent reduction of DCM concentrations in environmental scenarios.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ; ORCiD logo [4] ;  [5] ;  [5] ;  [5] ;  [6] ;  [2] ;  [1]
  1. Juniata College, Huntingdon, PA (United States). Lamendella Lab., Dept. of Biology; Wright Labs., LLC, Huntington, PA (United States)
  2. Juniata College, Huntingdon, PA (United States). Lamendella Lab., Dept. of Biology
  3. Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Graduate Education, Inst. for a Secure and Sustainable Environment; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
  4. Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Graduate Education, Inst. for a Secure and Sustainable Environment, Dept. of Microbiology, Dept. of Civil and Environmental Engineering, Dept. of Earth and Planetary Sciences; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
  5. CDM Smith, Edison, NJ (United States)
  6. California State Univ., Northridge, PA (United States). Dept. of Biology
Publication Date:
Grant/Contract Number:
AC05-00OR22725; DBI-1248096
Type:
Accepted Manuscript
Journal Name:
Frontiers in Microbiology
Additional Journal Information:
Journal Volume: 8; Journal Issue: n/a; Journal ID: ISSN 1664-302X
Publisher:
Frontiers Research Foundation
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; dichloromethane; DCM; 16S rRNA; biodegradation; xenobiotic; groundwater; monitored natural attenuation; bacterial community
OSTI Identifier:
1414676