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Using Geoscientific Analysis and Community Engagement to Analyze Exposures to Potential Groundwater Contamination Related to Hydrocarbon Extraction in Southwestern Pennsylvania

Abstract:

Understanding the health effects from potential groundwater contamination related to unconventional oil and gas development (UOGD) requires identifying specific locations of contamination, the nature of the contaminants and possible pathways of contamination. We analyzed potential groundwater contamination pathways from UOGD in a tri-county region of Southwestern PA (SWPA). We utilized community focus groups and geoscientific analysis to examine potential contamination pathways. In the focus groups, we gathered data on community perceptions of potential groundwater contamination, landscape transformations and health impacts related to UOGD. These data informed a statistical analysis of a large groundwater sample dataset from the region with over 7,000 samples each with approximately 40 chemical analytes.

Across all three counties, communities documented negative changes to water since the start of UOGD and raised concern about potential water contamination from UOGD chemical inputs (i.e. hydraulic fracturing fluids) and wastewater management. Specific analytes of concern were chloride and radioactive species. Various health concerns were raised, most prominently cancers, such as Ewing’s Sarcoma. We find small, statistically significant correlations in the study region between concentrations of barium and strontium in groundwater and proximity and density of UOGD. The most likely contamination pathway is brine leaks/spills from wastewater management, as these correlations are strengthened when we consider correlations with documented pollution incidents (e.g., spills). While barium and strontium are unlikely to pose a health risk at the concentrations we observe, other trace elements in UOGD wastewaters may pose a health risk at lower concentrations. Although the water sampling dataset did not include direct measurements of radioactive species, an estimate using geochemical ratio analysis suggests that exposure to radioactive elements in leaked wastewater is unlikely to exceed EPA limits. In conclusion, we find small but significant correlations between UOGD and brine salt species, likely the result of a small number of sites with presumable groundwater contamination from wastewater leaks or spills. These findings link to community concerns regarding wastewater management.