Organic Compounds Associated with Hydraulic Fracturing: Groundwater Composition and Natural Attenuation Potential by

Organic Compounds Associated with Hydraulic Fracturing: Groundwater Composition and Natural Attenuation Potential by Brian D. Drollette Department of Civil and Environmental Engineering Duke University Date:_______________________ Approved: ___________________________ Desiree Plata, Supervisor ___________________________ Lee Ferguson ___________________________ Avner Vengosh An abstract of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the Department of Civil and Environmental Engineering in the Graduate School of Duke University 2014 Copyright by Brian D. Drollette 2014 iv Abstract As the United States slowly transitions from coal and foreign oil to more renewable energy sources, domestic natural gas is being utilized as an intermediate “bridge fuel”. Advances in horizontal drilling and hydraulic fracturing have increased gas extraction and exploration over the past ten years. The massive quantities of fluids used to fracture gas-producing shale plays contain potentially toxic chemicals and the wastes are highly saline and contain naturally occurring radioactive materials. It is unclear if there are risks to shallow drinking water aquifers and if the chemical constituents of fracking fluid are inherently biodegradable if released into the environment. Monitoring the fate of these chemicals as they enter the environment is critical to understanding potential health hazards and persistence. Here, groundwater monitoring for organic compounds coupled with spatial data analysis indicates no subsurface contamination from hydraulic fracturing of the Marcellus Shale in northeastern Pennsylvania. However, a chemical fingerprint is presented suggesting increased organic compounds in shallow groundwater are due to subsurface mixing with brine containing geogenic hydrocarbons from the Marcellus Shale. To investigate the fate and extent of the chemicals used in hydraulic fracturing and the associated wastes if released into the environment, bench-scale reactor experiments were performed. These reactors contained a synthetic hydraulic fracturing