Refining the Vapor Intrusion Conceptual Model:  From Soils to Sewers

 Lila Beckley

Abstract

 Vapor intrusion is the migration of volatile organic compounds from contaminated groundwater or soil into buildings.  Because it is a mechanism that could potentially expose people to harmful chemicals, vapor intrusion is scrutinized in a variety of contexts including real estate transactions and regulatory oversight of contaminated site cleanups.  The conventional vapor intrusion conceptual model that has been recognized since the 1990s involves contaminant transport up through the vadose zone into buildings.  In recent years, however, there has been a growing recognition that sewers and utility tunnels can act as preferential pathways for vapor intrusion.  In this talk, I will discuss the evolving vapor intrusion conceptual model including conventional mechanisms, the influence of shallow soils on vapor migration in the subsurface, and the role of sewers/utility tunnels as preferential pathways.  Presenting data from several of GSI’s ESTCP VI research projects, I will also provide recommendations for evaluating sites to determine whether vapor intrusion is a concern. 

 Bio

 Lila Beckley is a senior geologist with GSI Environmental Inc., in Austin, Texas, with more than 24 years of experience in the environmental field.  She received M.A. and B.S. degrees in Geological Sciences from the University of Texas at Austin.  Her current focus areas include regulatory and litigation support, and vapor intrusion.  In the area of vapor intrusion, she has developed investigation protocols through DoD-funded research; conducted assessments of residential, industrial, and military sites around the U.S.; and developed guidance and training.  Prior to joining GSI, Lila worked in enforcement and remediation programs at the Texas Commission on Environmental Quality (TCEQ), in various roles ranging from project to program management.