SHALE GAS DEVELOPMENT AND WASTEWATER SPILLS AS A DRIVER FOR BIOLOGICAL CHANGES IN SECOND-ORDER STREAMS OF NORTHCENTRAL PENNSYLVANIA

Shale gas development, which targets unconventional formations using horizontal drilling and hydraulic fracturing, has sparked controversy over its environmental impacts. Concerns surrounding water resources have developed over potential releases of saline wastewater or fracking fluids into early order streams via wellpad spills or poorly constructed impoundments. This study seeks to elucidate how spills of shale gas wastewater in addition to shale gas development may alter stream chemistry and biological communities of fish and macroinvertebrates in the northcentral region of Pennsylvania. Northcentral Pennsylvania was selected to isolate effects of drilling since it has minimal confounding land uses like agriculture and major roads. Second-order streams within HUC-12 watersheds were selected for water sampling based on whether upstream conditions contained: i) unconventional drilling including impoundment and spill violations; ii) unconventional drilling with impoundment violations only; iii) unconventional drilling with no documented violations; or iv) no history of drilling or violations. Water samples were analyzed for major cations and anions, including species indicative of shale gas wastewater (Br, Cl, Ba, Sr). Strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) were used to seek evidence for the presence of wastewater brines unique to the Marcellus formation. Current directions involve identifying more recent wastewater spills in the watershed as well as beginning macroinvertebrate and fish sampling protocol. Comparing assessments of biological integrity to ion concentrations and geochemical tracers of potential shale gas-related impacts can inform how shale gas development and shale gas wastewaters may be impacting the ecosystem dynamics of early order streams.