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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #316961
Title: Evaluation of native microbial soil populations at a trichloroethylene contaminated Superfund site in the presence of a permeable reactive barrier (biowall) using a metagenomics approach

Author
item DE GUZMAN, NINO - Collaborator
item Hapeman, Cathleen
item MCCONNELL, L.L. - Collaborator
item MILLNER, P.D. - Collaborator
item TORRENTS, A. - Collaborator
item KJELLERUP, B. - Collaborator

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2015
Publication Date: 5/3/2015
Citation: De Guzman, N., Hapeman, C.J., Mcconnell, L., Millner, P., Torrents, A., Kjellerup, B. 2015. Evaluation of native microbial soil populations at a trichloroethylene contaminated Superfund site in the presence of a permeable reactive barrier (biowall) using a metagenomics approach [abstract]. Society of Environmental Toxicology and Chemistry Europe. MO154.

Interpretive Summary:

Technical Abstract: The Beaverdam Road Landfill occupies 3.5 acres and was an active disposal site for miscellaneous non-hazardous waste from 1943 to 1990, before being capped. In 1994, this site was included on the Nation Priorities List (NPL) for periodic inspection and remediation in accordance with the program regulations. In 2002, trichloroethylene (TCE) was identified in the groundwater as high as 435 ppb, whereas the Maximum Contaminant Level (MCL) in drinking water is 5 ppb. The contaminant source remains unidentified. The construction of a permeable reactive barrier (PRB) was determined to be the least invasive method of remediation. Previous research in this field has focused on rudimentary interactions between PRB materials and TCE either in situ or in lab-scale reactors under ideal conditions, instead of the temperature range common to groundwater (10-15 oC), a critical component to TCE behavior. Furthermore, the subsequent microbial colonization of the PRB material from the surrounding soil microbiota has not been sufficiently investigated. The objectives of this study were to determine if any TCE-degrading microbial communities could be found in the site soil and if they could ultimately colonize the PRB material to increase the degradation capability of the engineered structure. DNA was extracted from native soil samples from a highly, a moderately, and an uncontaminated area at the site to evaluate the microbial communities for TCE degradation potential. DNA was also extracted from the PRB building material shortly after installation and one year later, to track the colonization of the material. Microbial identification and monitoring has been done utilizing 16S rRNA sequencing and taxomic analysis (Illumina HiSeq2500). The presence of tceA, vcrA, and bvcA genes, linked to TCE degradation, were applied for quantitative analysis using qPCR. A commercially available consortium, SDC-9, was used as a control to gauge Dehalococcoides spp. behavior and presence in this environment. Anaerobic batch reactors (12 oC) were subsequently constructed and packed with mulch, compost, and general-purpose sand either with or without zero-valent iron (ZVI) and/or glycerol to determine TCE degradation potential. If TCE degrading microbial communities were not able to colonize the PRB materials in the field, augmentation options will be explored at the bench scale then evaluated for deployment in the field. Results of this research will be useful to scientists and engineers who want to improve the effectiveness of biowall technologies.