Unknown

Problem Severity

Petroleum-contaminated soils associated with decommissioned 500 gallon underground heating oil tank. a A release investigation was conducted in FY92, and soil and groundwater samples were collected. TPH and DRO concentrations were detected in soil above ADEC cleanup criteria, and groundwater contained dissolved PHC constituents, including benzene, above MCLs. The release investigation determined that the soil contamination resulted from the former 2,000-gallon heating oil tank, as field observations during excavation did not indicate the presence of a release from UST 52-A-12. A FY94 CAP selected in-situ bioremediation by air sparging as the most cost-effective remediation alternative, which commenced in FY95. The soil and groundwater were not sampled between FY95 and the FY99 SI. Soil and water samples were collected during the FY99 SI, which focused on assessing remedial progress. Analyses of the soil and water samples suggested that significant remediation had occurred. However, sample results still indicated that DRO concentrations were above ADEC cleanup criteria in soil and groundwater. Based on the FY99 SI results, FAA consultants recommended further remediation or institutional controls (such as limiting the land to industrial use), and decommissioning the air sparging system, as it would have limited effectiveness in remediating site soils in a suitable timeframe. However, the utility building is scheduled to be removed; thus, the FY99 SI recommended excavating and landspreading the remaining contaminated soil after building demolition. In FY03, FAA began groundwater monitoring and will continue groundwater monitoring through FY10.

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