An Examination of Empirically Derived Attenuation Factors at a Large-Scale TCE Vapor Intrusion Project

摘要

Background/Objectives. The widespread use of chlorinated solvents has resulted in scores of legacy sites where vapor intrusion has the potential to result in unacceptable health risks in affected communities. While the physical and chemical factors that govern the extent to which vapors are transported in the subsurface and enter enclosed spaces are generally well understood, site specific factors and local variability can introduce considerable uncertainty when modeling vapor intrusion. Since 2005, we have been investigating and remediating a large, shallow TCE groundwater plume that extends throughout a residential neighborhood in southern Ontario. The investigation has included semi-annual groundwater monitoring at over 130 locations and annual indoor air testing at over 500 locations. As such, the project offers an unprecedented ability to develop attenuation factors based on an empirical examination of closely paired groundwater and indoor air data across the study area.