Collaborative Research: Impacts of biocides associated with hydraulic fracturing on aquatic microbial communities.

Hydraulic fracturing (HF), commonly called "fracking", is a method for recovery of oil and gas using high pressure water, sand, and chemicals to fracture rocks, releasing oil and gas. This process transformed the U.S. energy industry, but more research is needed to study the environmental impacts of HF. This project at Juniata College, in collaboration with researchers at Michigan Technological University and the University of Tennessee Knoxville, will focus on the environmental impacts of biocides, some of the most commonly used chemicals in HF. Biocides are designed to kill microbes and are used in HF to protect equipment from microbial corrosion and to preserve the quality of oil and gas. However, once exposed to biocides, naturally-occurring microorganisms can become resistant to these chemicals. Because of this link between biocide resistance and the ability of microbes to become resistant to medications, it is important to clarify the impact of industrial biocides associated with HF on the environment, and the processes leading to biocide resistance. If successful, this research will lead to better strategies to identify and mitigate the potential effects of biocides on the environment and public health, protecting the Nation's water security while enabling the use of an important source of raw energy materials. <br/><br/>The goal of this study is to better understand the environmental impacts of HF and how the use of industrial biocides in HF operations may contribute to development of antimicrobial resistance (AMR) in aquatic microbial communities. Previous work demonstrated altered microbial community compositions in streams impacted by HF operations as well as increased tolerance to biocides in streams impacted by HF. Several streams in Pennsylvania were selected for this study based on their reception of HF wastewater due to spills or close proximity to active HF wells. Another set of streams with no active HF operations were selected as control settings. The initial objective of this work will be to study links between the observed changes in high HF active streams and potential releases of HF wastewater. Chemical tracers, isotopic signatures, biocide concentrations, and biocide breakdown products will be measured in HF-impacted streams and compared to both HF wastewater and control streams. The microbial community composition and functions within these 3 general aquatic ecosystems will also be studied using high-throughput sequencing to elucidate the impact of HF operations on biogeochemical cycling and assess the potential for microbes to be used as sensitive bio-indicators of HF impacts. In addition to investigating the impact of HF operations on streams and the consequences of AMR, studies will be performed to investigate the biological mechanism for resistance to various industrial biocides using biocide resistant strains isolated from HF wastewater and HF-impacted streams. Transcriptomics will be employed to assess the microbial response to industrial biocides. The levels of biocide-resistant strains and AMR genes will be determined in these environments over multiple years to investigate the long-term impact of HF activities on the development and persistence of strains resistant to antimicrobials. This project will provide insights into links between HF activity, biocide resistance, and the pathways controlling the fate of biocides in these settings. If successful, this research could serve as the foundation for the development of future molecular diagnostic tools for detecting biocide contamination.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.