Groundwaters in Northeastern Pennsylvania near intense hydraulic fracturing activities exhibit few organic chemical impacts

Abstract

Hydrogeologic transport contributes to limited organic chemical contamination in a region of intense gas extraction, even 10 years post-development.

Unconventional Oil and Gas Development Exposure and Risk of Childhood Acute Lymphoblastic Leukemia: A Case–Control Study in Pennsylvania, 2009–2017

“…Maternal occupational and ambient exposure to benzene, which is known to be used or produced by UOGD, in the air 22 , 32 or in the form of solvents, paints, and petroleum during pregnancy have been associated with elevated odds of ALL. 35 Benzene has been detected in multiple groundwater studies in this region focused on UOGD 41 , 65 , 96 – 99 and in biological samples from communities near oil and gas development. 100 However, it is also possible that these results arose because the water pathway-specific metric produced exposure estimates similar to those of the aggregate metric, particularly when dichotomized.…”

Assessing Unconventional Oil and Gas Exposure in the Appalachian Basin: Comparison of Exposure Surrogates and Residential Drinking Water Measurements

“…UOG-related contamination events could occur with low frequency or be transient. , Thus, individual groundwater samples collected at one point in time may be unlikely to capture a contamination event. In addition to these temporal constraints, physically based transport modeling work conducted under this project demonstrated that the longitudinal extent of the probabilistic capture zones (the area from which a drinking water well likely draws its groundwater) around the PA homes was generally smaller than distances to the nearest UOG wells (<1.6 km with a median of 0.86 km). , Therefore, the appropriate buffer sizes when considering water quality impacts may be considerably smaller than those traditionally applied in health studies, which are designed to capture a range of possible environmental stressors. Additionally, the multiple natural, industrial, and other sources make it difficult to link the occurrence of particular inorganic chemicals to UOG activity. , Studies focused on source apportionment use other methods, such as ratios of inorganic ions (e.g., bromide/chloride), as potential indicators of UOG-related contamination. , …”

Groundwater Methane in Northeastern Pennsylvania Attributable to Thermogenic Sources and Hydrogeomorphologic Migration Pathways

“…Water samples for dissolved hydrocarbon (methane, ethane, and propane) analysis were collected from 90 domestic wells and 4 springs (89 in Bradford County and 5 in Tioga County) in NE PA as part of the Yale water and energy resource study (see various refs –). Sample locations were the outcome of recruitment efforts (semi-random), election to participation (which is impossible to fully randomize), and eligibility.…”

“…Methane isotopes were analyzed at the UC Davis Stable Isotope Facility. The measurement of dissolved ion species, the construction of spatial metrics and topographical classes, and the collection of pre-drilling data are also discussed in the Supporting Information and presented in other publications. − Any referenced pre-drilling data were acquired from the Shale Network database , and matched with our sampling locations or provided by the homeowners.…”