Evaluating the potential for vapor intrusion at superfund sites in North Carolina contaminated with volatile organic compounds

Abstract

Abstract Smith, Kristin N. Master of Environmental Assessment Program. Evaluating the Potential for Vapor Intrusion at Superfund Sites in North Carolina Contaminated with Volatile Organic Compounds. Vapor intrusion is the migration of volatile chemicals into overlying buildings. While vapor intrusion has been a known pathway for many years, there is concern that some sites may still be at risk for human exposure. The purpose of this project was to evaluate the potential for vapor intrusion at a subset of Superfund sites in North Carolina. The primary constituents of concern for this project were volatile organic compounds. Twenty-seven sites contaminated with volatile organic compounds were evaluated using the United States Environmental Protection Agency’s Office of Solid Waste and Emergency Response Technical Guidance documents as a starting point for site criteria. These documents detail the U.S. EPA's approach for assessing and mitigating vapor intrusion at sites. For this project, a site calculator was developed to create a consistent risk-ranking system for vapor intrusion potential. The site calculator uses a set of possible inputs and scores for each criteria along with a "weight of importance" to create a risk score, zero to five, with five being the highest risk. Of the twenty-seven sites assessed, twenty-four resulted in a risk score of one or zero indicating little to no risk for vapor intrusion. Two sites resulted in a moderate risk score of two. The highest risk score from the sites in North Carolina was a three, which is still considered a moderate risk. This paper demonstrates the effectiveness of the site calculator tool in evaluating the potential for vapor intrusion.