Assessment of surface water chloride and conductivity trends in areas of unconventional oil and gas development-Why existing national data sets cannot tell us what we would like to know

Abstract

Heightened concern regarding the potential effects of unconventional oil and gas development on regional water quality has emerged, but the few studies on this topic are limited in geographic scope. Here we evaluate the potential utility of national and publicly available water-quality data sets for addressing questions regarding unconventional oil and gas development. We used existing U.S. Geological Survey and U.S. Environmental Protection Agency data sets to increase understanding of the spatial distribution of unconventional oil and gas development in the U.S. and broadly assess surface water quality trends in these areas. Based on sample size limitations, we were able to estimate trends in specific conductance (SC) and chloride (Cl 2 ) from 1970 to 2010 in 16% (n 5 155) of the watersheds with unconventional oil and gas resources. We assessed these trends relative to spatiotemporal distributions of hydraulically fractured wells. Results from this limited analysis suggest no consistent and widespread trends in surface water quality for SC and Cl 2 in areas with increasing unconventional oil and gas development and highlight limitations of existing national databases for addressing questions regarding unconventional oil and gas development and water quality.

Monitoring Marcellus: A Case Study of a Collaborative Volunteer Monitoring Project to Document the Impact of Unconventional Shale Gas Extraction on Small Streams

“…Recent analysis of the large dataset in the Shale Network database 1 Vidic et al 2013) has failed to identify pollution incidents, leading some researchers to the conclusion that sampling density requirements to detect pollution events are so high that documenting pollution events in real-time using traditional methods is unlikely. This conclusion has been corroborated by a recent USGS report (Bowen et al 2015) discussing the inadequacy of our national databases to document impacts of shale gas extraction.…”

“…Because the extraction activities are occurring over a very large and remote geographic area in Pennsylvania and because spill events can be quite ephemeral, the documentation of these impacts is extremely challenging (Brantley et al 2014). In this knowledge landscape of scarce data and controversial environmental threats (Bowen et al 2015;Entrekin et al 2011;Vidic et al 2013), the unprecedented rapid growth of the shale gas extraction industry in Pennsylvania has motivated concerned citizens to seek ways to help fill data gaps and contribute to sound evidence for public policy decisions. As a response to requests from community members, the Alliance for Aquatic Resource Monitoring (ALLARM) developed a volunteer-friendly protocol for early detection and reporting of surface water contamination by shale gas extraction activities in 2010 (Wilderman and Monismith 2012).…”

Quantifying Market and Non-market Benefits and Costs of Hydraulic Fracturing in the United States: A Summary of the Literature

“…The pathways by which hydraulic fracturing can contaminate surface water resources include leakage from pits where flowback and produced water is stored, overflow from these storage pits, spills during transport of hydraulic fracturing fluids, other chemicals and waste (Kahrilas et al, 2015). Several studies document cases of water contamination due to oil and gas production (for example see Bowen et al, 2015, Jackson et al, 2013, Olmstead et al, 2013, Osborne et al 2011, Vengosh et al, 2014. Produced water is the largest single waste stream from oil and gas development and is one potential source of surface and groundwater contamination (Clark and Veil, 2009).…”

Density of river otters (Lontra canadensis) in relation to energy development in the Green River Basin, Wyoming

“…Hydraulic fracturing, an increasingly common drilling method for extraction of natural gas, relies on the injection of large quantities of water with hundreds of chemicals deep into the ground (Bowen et al, 2015). Nearly 75% of these chemicals are known to negatively affect multiple organ-systems in humans (Colborn et al, 2011).…”

“…Nonetheless, because oil and gas deposits are primarily associated with sediments of marine origin, produced waters usually contain salts in higher concentrations than found in freshwater streams. Thus, changes in conductivity, which reflects total dissolved solids and salinity, could indicate anthropogenic inputs of contaminants into surface waters (Bowen et al, 2015).…”