Hydrocarbon Extraction and Risk to Groundwater in Pennsylvania: Part 2. An Analysis of Water Quality in the Oldest Hydrocarbon Basin in the United States

This report, available for download below, presents a study led by co-principal investigators Jennifer Baka and Susan L. Brantley (Pennsylvania State University) and colleagues. This Part 2 study provides more recent water quality data from surveys conducted in areas where evidence gathered in Part 1 suggested that groundwater may have been contaminated by unconventional oil and gas (UOGD).

Key takeaways:

• Part 1 of the study, based on decade-old water quality data, identified elevated salts as a potential indicator of groundwater contamination related to unconventional oil and gas development (UOGD) in areas of Pennsylvania. It also documented community concerns about potential radiation exposures and water quality impacts from UOGD waste management.
• In Part 2, this study provides more recent water quality data from surveys conducted in areas where evidence gathered in Part 1 suggested that groundwater may have been contaminated by UOGD.
• The investigators collected 97 water samples from private groundwater wells, springs, and streams near oil and gas activities, as well as control sites, and analyzed them for 41 chemicals associated with UOGD and human health. They also used multiple statistical analyses and chemical fingerprinting to identify impacts from UOGD versus other sources.
• The investigators found that few analytes exceeded drinking water standards, and exceedances were limited to secondary standards, which are based on aesthetic qualities rather than health effects. Overall, based on multiple lines of evidence, the investigators found no conclusive evidence of UOGD-related impacts in private groundwater wells, noting that geological, geographical, and land use variation across the relatively small number of sample sites may also explain their observations.
• This study contributes to the broader understanding of groundwater and drinking water quality in areas proximate to UOGD and adds valuable data that may help distinguish localized UOGD-related impacts on groundwater from broader regional effects of historical energy extraction or geology. The study also directly addressed community concerns by investigating whether private drinking water wells were contaminated by UOGD.