Bethel conducted a site investigation at the FAA Mount Santa Rosa Air Route Surveillance Radar (ARSR) facility in Yigo, Guam. The project objective was to collect information sufficient to delineate the lateral and vertical extent of diesel fuel contamination in subsurface soil that exceeds action limits established by the Guam Environmental Protection Agency. The contamination occurred in the mid-1990s from leaking components of a former underground storage tank (UST) and associated piping that fueled emergency generators at one of the facility’s buildings.
This project required a lot of up-front planning to obtain the appropriate permits required by the Anderson Air Force Base (now part of Joint Base Marianas). These permits included a base dig permit and MEC clearance.
To delineate contaminated soil, Bethel advanced eight borings using a hollow-stem augur drill rig across the investigation area to depths up to 33.5 feet below the ground surface. Split-spoon cores were collected at 5-foot intervals from each boring for lithologic logging, field screening, and analytical soil sampling. A total of 43 soil samples were collected from the cores and analyzed for total petroleum hydrocarbons – diesel (TPHd); benzene, toluene, ethylbenzene, and xylenes (BTEX); and polynuclear aromatic hydrocarbons (PAH). Groundwater was not encountered in any boring.
Bethel concluded that diesel-contaminated soil was present over 500 square feet of the investigation area and at depths to at least 33.5 feet. The volume of contaminated soil was estimated at 475 cubic yards. Based on data collected during the SI, Bethel recommended that FAA evaluate three remedial action options to address contamination in subsurface soils at the site including a partial removal action, chemical treatment, and administrative controls.
Work performed
- Work Plan Preparation and Approval
- Delineation of Contaminated Soil
- Working at an Active Radar Site
- Munitions and Explosives of Concern (MEC) Clearance
- IDW Disposal
- Logistics of Working at Remote Site on an Active Air Force Base
