Unconventional shale gas extraction in the Marcellus has expanded throughout Pennsylvania since 2005, and poses potential risks to water resources. This study investigated water quality in Cross Creek County Park (CCCP), Washington County, Pennsylvania, surface waters and nearby residential water wells. Twenty-five wells have been drilled within CCCP over the past 8 years. Six sites were monitored bi-monthly for temperature, pH, dissolved oxygen, and conductivity, as well as selected anions, cations, and light hydrocarbons. Detection of methane and ethane, surfactants, and other water chemistry parameters (e.g., mass ratios) suggest water quality has been impacted for sites Cross Creek 1, Streams A and C, and some well water samples. Spatial patterns were analyzed to evaluate drilling, mining, agriculture, and hydrology of the Cross Creek Watershed. File review of oil and gas documents revealed that drilling wastes were buried within the park, suggesting a possible source of contamination for the impacted streams
