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Corrective Action Plan G Time Od Company Property No 04-049 14000 East Highway 88 Lockeford CA _ September 8 1998 pond for surface runoff during rainfall events is located at the south corner of the Site (Figure 2) This drainage is typically dry 2.4 SOIL VAPOR EXTRACTION FEASIBILITY TESTS SVE tests were conducted at the Site in December 1992 and March 1998 TPHg concentrations in tntluent samples collected during the March 1998 test ranged from 139 ppmv (parts per million by volume) (W-6)to 179,000 ppmv(W-3) Analytical results of air samples collected from this test are summarized in Table 5 TPHg removal rates during the March 1998 test ranged from 1 1 lbs/day (pounds per day) (W-6) to 1,425 lbs/day (W-3) Mass removal rates from the March 1998 test are summarized in Table 6 Based on the flow rates achieved, Site lithology, and data collected during previous investigations, the radius of influence at the site was estimated to be 50 feet 2.5 EXTENT OF PETROLEUM HYDROCARBON IMPACTS The extent of petroleum hydrocarbons in soil and groundwater is discussed below No separate phase hydrocarbons have been detected at the Site Calculations for the mass of hydrocarbons in the subsurface at the Site are provided in Appendix C These calculations indicate that between 12,000 and 36,000 pounds of hydrocarbons are present in the subsurface at the Site 2 5.1 Extent of Adsorbed Petroleum hydrocarbons TPHg concentrations in soil greater than 1,000 mg/kg have only been detected witlun 20 feet of the former UST pit and dispenser islands Horizontal distribution of detectable TPHg is illustrated on Figure 6 This area is approximately 8,500 square feet Maximum TPHg concentrations have typically been detected at a depth of approximately 30 feet Vertical distribution of TPHg is illustrated on geologic cross-sections A-A' and B-B' (Figure 5) Time 0t1\Lockef6rd\CAP wpd i