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locations, the dispensers and product lines Laboratory analytical results detected total petroleum hydrocarbons as gasoline and diesel (TPH-g and TPH-d),benzene,toluene,ethyl benzene and total xylene (BTEX) and fuel additives in the soil samples collected from the UST excavations and dispenser areas, the latter exhibited significant staining and hydrocarbon odor PREVIOUS SITE ASSESSMENT On I 1 August 1999, an additional 150 cubic yards of significantly petroleum-impacted soil was removed from the beneath the three former dispenser areas Laboratory analytical data indicated a significant concentration of TPH-g,TPH-d,BTEX compounds and fuel additives in the soil samples collected On 29 October and 01 November 1999, AGE advanced eight soil probe borings to a depth of 30 feet bsg at the site to obtain soil and grab ground water samples TPH-g,TPH-d, BTEX and methyl tert- butyl ether (MTBE) were detected in soil samples analyzed at maximum concentrations of 49 milligrams per kilogram(mg/kg), 180 mg/kg 0 36 mg/kg,and 78 micrograms per kilograms(µg/kg), respectively. Laboratory analysis of grab ground water samples indicate that the highest concentrations of TPH-g,TPH-d,BTEX and MTBE were in the vicinity of former dispenser islands Based on the data collected,the dispenser islands appear to be the primary source of the hydrocarbon release Ground water monitoring wells MW-1 through MW-5 were installed On 27 and 28 September 2000 and monitored and sampled on 03 October 2000 TPH-g and TPH-d compounds were detected in CA only one of eleven soil samples, at similar concentrations of 170 mg/kg-, in addition, BTEX and A several additional volatile organic compounds were detected at concentrations up to 0 44 mg/kg M TPH-g,TPH-d and BTEX was detected i t o ground Rul bsamples collected on 03 October 2000 DO 1� at maximum concentrations of µg/1,2µg/1,and Ig�I respectively,in adpn,MTBE was detected in three ground water samples at a maximum concentration of 170 g Vm 'i1-g1ot 6b 6e.)$2LOt On 09 December 2003, three soil borings (CPT-1, CPT-2, and CPT-3) were advanced on site utilizing CPT technology to a total depth of approximately 110 feet bsg At each boring location, lithologic data was collected from the initial CPT boring, an immediately adjacent twin boring was then advanced to collect grab ground water samples CPT-1 was sampled between 55 feet and 60 feet bsg and between 80 feet and 84 feet bsg, CPT-2 was sampled between 55 feet and 60 feet bsg, between 89 feet and 94 feet bsg and between 110 feet and 114 feet bsg, and CPT-3 was sampled between 55 feet and 60 feet bsg, between 85 feet and 90 feet bsg and between 110 feet and 114 feet bsg HYDROGEOLOGICAL MODEL Based on the CPT results, AGE has assigned names to four informal zones, a vadose (unsaturated) zone and three hydrogeologic units Vadose Zone- Extending from surface grade to approximately 15 feet bsg, the depth to the water table The vadose zone is predominantly fine grained material Advanced GeoEnvironmental,Inc