This high volume retail gasoline station is situated upgradient of a public drinking water reservoir. Lubricating oil NAPL (Non-Aqueous Phase Liquid) was periodically detected in a particular site monitoring well. LEI delineated the limited area of impact and initiated treatment by eliminating the NAPL via dual phase extraction administered by a vacuum truck. A series of 3 Chemox (chemical oxidation) injection events were then conducted within the plume area over a 5 month period to address residual dissolved phase contaminants. Post treatment sampling revealed that the stringent clean up goals were met for this site
Assessment and remedial activities were conducted as a Release Abatement Measure (RAM) Modification . The following assessment activities were performed to adequately delineate the NAPL plume and any related soil impact.
Advanced 3 soil borings and completed as monitoring wells to provide additional data on soil and groundwater conditions proximal to the affected well
Field screened and laboratory analyzed selected soil and groundwater samples
A two tiered approach was selected for this site. The first tier addressed the NAPL while the second tier addressed residual dissolved phase contaminants:
A dual phase extraction event (recovering vapors and liquids simultaneously) performed by a vacuum truck removed over 50 gallons of NAPL and groundwater, leaving the impacted well free of NAPL
3 separate Chemox injection events were administered in September 1999, October 1999 and January 2000.
Compared site specific standards to actual groundwater quality indicating that groundwater did not require any further remedial actions
Performed a method 2 Risk Assessment which concluded that No Further Remedial Actions were required
Completed a RAO (Response Action Outcome)
Key Monitoring Results:
Current Site Status:
Site Closed — No Further Remedial Actions required