Expedited approach to a carbon tetrachloride spill interim remedial action

摘要

Monitored natural attenuation was selected as an interim measure for a carbon tetrachloride spill site where source removal or in situ treatment cannot currently be implemented due to the surrounding infrastructure. Rather than delay action until the site is more accessible to an interim action, this more expedited approach would support a final action. Individual Hazard Substance Site (IHSS) 118.1 is a former underground storage tank at Rocky Flats Environmental Technology Site (RFETS) that stored carbon tetrachloride for process use. Inadvertent releases associated with filling and failure of the tank system resulted in an accumulation of carbon tetrachloride in a bedrock depression around a group of former process waste tanks. Access to the source of contamination is obstructed by numerous utilities, the process waste tanks, and other components of the site infrastructure that limit the ability to conduct an effective remedial action. A preremedial field investigation was conducted in September 1997 to identify and delineate the extent of the dense nonaqueous phase liquid (DNAPL) in the subsurface. Data collected from the investigation revealed that natural processes might be limiting the migration of contaminants from the source area.