INVESTIGATING SALTS AND RADIOACTIVE SPECIES IN GROUND AND SURFACE WATERS NEARBY OIL AND GAS WELLS

Oil and gas development can cause changes in groundwater systems, particularly when gases or fluids escape from poorly constructed wellbores. Whether radon, a colorless, odorless gas known to cause lung cancer, can also increase in groundwater nearby oil and gas development remains poorly constrained. We looked upon multiple lines of evidence to conclude if there was an impact of oil and gas drilling on groundwater quality. With the utilization of a large (n = 3745) dataset of groundwater samples across Pennsylvania (PA), we studied if stratigraphy, lithology, well depth, and proximity to oil and gas wells impact radon activities. We compared median radon activities across different lithologies and formations, and created models to investigate relationships between radon activities and well depths, the distance from oil and gas wells, and surrounding density of oil and gas drilling. In addition, we collected surface and groundwater samples near a leaking abandoned gas well in Wallace Run in Centre County, PA and analyzed anions and cations with respect to water chemistry. From the results gathered, we found radon activities were highest in Tertiary, Devonian, and Triassic age formations and schists, quartzite, and sandstones. We analyzed and found no correlation with well depth but a significant increase in radon activities statewide nearby shale gas wells. However, increases in radon nearby oil and gas wells may reflect higher baseline levels of radon in oil and gas regions, as samples within a 10 kilometer distance from shale gas development do not show a significant increase with respect to shale gas well proximity. From the information gathered, leakage of radon and other contaminants in groundwater systems is predominantly controlled by geology rather than by development of shale gas wells. However, in specific areas statewide containing high radon activities, development of drilling sites could pose a risk.