The Effects of Marcellus Shale Gas Drilling Accidents on Wallace Mine Fen in the Moshannon State Forest, Pennsylvania

Abstract

In 2009, a Marcellus Shale gas-drilling company, EOG Resources, was fined $30,000 by the Pennsylvania Department of Environmental Protection (PA DEP) after several violations occurred at two well sites located on private land adjacent to Moshannon State Forest in Clearfield County, Pennsylvania. Three separate accidents resulted in the deposition of flowback water and frack fluids into Alex Branch, a small, sandy-bottom stream that flows through Wallace Mine Fen (WMF). Contaminated water also infiltrated the ground upslope from the fen. Water testing conducted by the PA DEP indicated elevated levels of Ba, Sr, Mn, Cl-, TDS, and specific conductance in two nearby springs. In 2012, I initiated a study to determine the ecological impacts of the accidents on WMF. I used a nearby wetland, Crystal Spring Bog (CSB, actually a fen), as a control and sampled amphibians, birds, fish, vegetation, and aquatic invertebrates at both sites. Tree core samples were collected from five trees at WMF and analyzed using Gas Chromatography Mass Spectrometry (GC/MS). Additionally, I collected water chemistry data from groundwater and surface water locations at both wetlands. Results showed no significant differences in vegetation, birds, fish, or aquatic invertebrates between the two wetlands. The GC/MS did not detect any contamination within trees, suggesting that the contamination may have occurred in short-term discharge events. Through point-count and visual encounter surveys, I detected differences in amphibian diversity and species richness between the sites. Due to the lack of pre-accident amphibian data, I also used habitat characteristics (i.e., vegetation and pool size) in an attempt to determine if differences 2 in amphibian populations are a result of the accidents or due to differences in habitat. I used vegetation frequency and percent cover to calculate importance values; those values were then used in an nMDS ordination. No major differences were detected in vegetation between sites; however, the ordination showed that CSB was wetter than WMF. I also compared pool area and depth between the two wetlands using a Mann-Whitney test. Pool area was significantly greater in CSB, but there was no difference in pool depth. Overall, habitat characteristics do not fully explain differences in amphibians between the wetlands and results suggest that the accidents at EOG gas drilling operations decreased amphibian diversity and abundance at WMF.