Unconventional oil and gas (UOG) have revolutionized the energy industry. However, the rampant growth in the industry, particularly the use of hydraulic fracturing (HF), has raised many environmental challenges. Through the HF process the injected mixture of water, chemicals, and sand flows back to the surface carrying unknown transformation products and naturally occurring materials from the subsurface. In addition, to oil and gas there is also byproduct water that is generated called produced water. Both flowback and produce water create wastewater handling issues and can pose environmental challenges in the case of accidental release or spill. In addition to chemical monitoring, environmental microbiomes can serve as good indicators of HF fluids and chemicals that accidently reach the environment. Microbiomes, or microbial community structure, can shift due to chemical presence that may be below limit of detection or has already been degraded. By sequencing the 16S rRNA gene of sediment and water in streams in high and low UOG activity areas in the Marcellus Shale we were able to use microbial community composition and random forest modeling to predict UOG activity with 69% accuracy. Further, we decided to test if microbes from streams impacted by UOG would respond to HF biocides glutaraldehyde and DBNPA as compared to pristine streams. Biocides are chemicals of concern for their high human and environmental toxicity. Biocides are added to HF fluids to prevent biocorrosion and gas souring. For these microcosms experiments we chose streams that had the most UOG impact and the wells within those streams had a history of using glutaraldehyde according to the self-disclosing database fracfocus.org. We found that UOG impacted streams overall microbial community is more resistant to the biocide glutaraldehyde than the pristine streams but glutaraldehyde degrades faster in pristine streams. However, the opposite was observed with the biocide DBNPA in microcosms constructed from the same streams. This showed that previous priming, can give the microbial community a memory effect that can have a lasting effect in microbial community structure and degradation potential in streams impacted by UOG operations. These changes can be utilized for environmental monitoring and to determine the resilience of a stream in case of accidental release.

Microbiomes as biosensors of unconventional oil and gas activity

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.