American Barrel Superfund Site / Vapor Intrusion Investigation

Client: PacifiCorp Environmental Remediation Company
Location: Salt Lake City, Utah

Modeling of groundwater data from an earlier investigation at the American Barrel Superfund Site indicated a potential risk to some nearby residences from the inhalation of volatile compounds emanating from the groundwater. At the EPA’s request, SAGE conducted a vapor intrusion investigation consisting of soil gas, indoor air, and outdoor (ambient) air sampling. To determine if there were any potential indoor sources of the contaminants of concern, we inspected the building and interviewed the occupants prior to sampling.

Benzene, toluene and xylene were detected in both indoor and outdoor air at similar concentrations. Benzene was also present in soil gas beneath the buildings, but modeling of the soil gas data indicated that the predicted indoor air concentrations due to vapor intrusion were below screening levels. Based on studies of benzene concentrations in urban areas, we concluded that the presence of volatiles inside and around the residence was likely due to background air concentrations rather than vapor intrusion from the groundwater plume.