TPH Criteria Working Group Demonstration Field Sampling Report: Robins Air Force Base Warner-Robins GA

Underground storage tank Site 70, Robins Air Force Base, Georgia, is part of a large aircraft refueling/defueling hydrant system. Site 70 was impacted by JP-4 and JP-8 jet fuels through spill, overflows and leaks dating back many years. This total pertoleum hydrocarbon (TPH) containmation has been identified and interim corrective action applied to remove free product from above the shallow groundwater table. Using limited site data and the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG or Working Group) approach for evaluation of weathered fuel spills, a Tier 1 Risk-Based Corrective Action (RBCA) analysis demonstration was performed. Soils from the site were analyzed using the Direct Method recommended by the Working Group to characterize the fuel residuals present in terms of 13 total petroleum hydrocarbon (TPH) fractions. The TPH contamination present was composed predominantly of aliphatic equivalent carbon (EC) fractions EC8 to ECi6 with some EClO to ECi6 aromatics. The lowest average risk-based screening level (RBSL) calculated for the current commercial use scenario was approximately 9000 mgikg for the direct soil to skin contact pathway. For a futuristic residential scenario, the lowest average RBSL was about 3000 mgikg for the contaminant leaching to groundwater pathway. This demonstration, however, does not represent a complete site assessment as only soil contamination pathways were evaluated.