Groundwater Vulnerability to Contamination from Abandoned Oil and Gas Wells in the Appalachian Basin Region

Abstract

The origin of the oil industry is in the Appalachian Basin, which has resulted in thousands of abandoned wells over the years. Improperly sealed wells may leak contaminants into the groundwater, which introduces public health risks to a resource that millions of Americans rely on for drinking water. While methane emissions from abandoned wells are well-studied, aqueous contamination risks remain understudied, especially with regard to human exposure through domestic groundwater wells. This project quantifies the vulnerability of groundwater and its population due to contamination coming from abandoned wells. The total number of people relying on private drinking wells is determined and then used to analyze its spatial distribution by applying a hotspot analysis. The project employs a source-pathway-receptor framework. In this framework, the source consists of a dataset of abandoned wells, while the pathway includes USGS-developed programs ModFlow-6 and ModPath-7, which are used to track particles through the groundwater. The receptors in this system are private drinking wells. In total, an area of 8,815.3 km2 is determined to show vulnerability coming from abandoned wells, potentially exposing a population of 402,948 people that rely on private drinking wells. Particles were tracked often shorter than 2 km, but notable outliers reached almost 17 km. These results emphasize the risk to public health due to the legacy impacts of the oil industry, and thus should be considered in future environmental policy and energy planning.