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Appendix A . AGE NC Project No 99-0570 ' Page 3 of 5 ' 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 ' Three limited excavations in the northeast edge of the former dispensers removed an estimated 150 cubic yards of significantly petroleum hydrocarbon-Impacted soil The total depth of the three ' excavations was 8 feet bsg The sidewalls and floor of the excavations EXE2 and EXE3 exposed hydrocarbon-Impacted soil Hydrocarbon-stained soil was not apparent In the final sidewalls and floor of excavation EXE1 Soil samples were collected from the excavation side walls at a depth of ' 8 feet bsg and a soil sample was collected from the floor of the southernmost excavation(EXE I) at a depth of 8 feet bsg The analytical data indicated that the highest concentrations of TPH-g were in excavations EXE2 and EXE3 at the northeastern edge of the dispenser area, near well MW-2 ' TPH-g was detected in the eastern soil sample from excavation EXE2 at a concentration of 17,000 mg/kg TPH-g was also detected in the soil sample from the southern edge of excavation ' EXE3 at a concentration of 11,000 mg/kg BTEX compounds were detected at concentrations as high as 2,300 mg/kg The highest concentration of benzene, 15 mg/kg, was detected in the eastern sample from excavation EXE2 Fuel additives were detected in samples from excavations EXE2 and ' EXE3 TPH-d was detected In the soil samples from EXE2 and EXE3, which were also impacted with TPH-g and BTEX compounds Low concentrations of TPH-d were detected in two soil samples from EXE1 The stockpiled soil was impacted by low to moderate concentrations of petroleum ' hydrocarbons and fuel additives Soil from B-1,B-2,and B-7 at 15 feet bsg had low concentrations of hydrocarbons,while soil from ' B-1,B-6,and B-7 at 10 and 15 feet,as well as B-2 at 10, 15, and 20 feet bsg had low concentrations of fuel additives(MTBE) Hydrocarbon-impacted ground wat rl3s c 4teVsd at B-1,B-6,B-7,and B-8 and MTBE was detected in grab ground water samples fromt; -6 and -7 MTBE was detected ' by EPA method 8260 in all grab ground water samples up to 150 µg/l (B-6) VM_ 4j%r-joc ' HYDROGEOLOGIC MODEL Based on the CPT results,AGE has assigned names to four Informal zones a vadose (unsaturated) ' zone and three hydrogeologic units Vadose Zone - This zone extends from surface grade to approximately 15 feet bsg,the depth to the ' water table The vadose zone Is predominantly fine-grained ned material from surfacerg�ade�to 15 feet bsg�ara:ctenzed ained sand unit occiuring between 20 feet and 25 feet bsg at CPT-2 The zone . s cw pore pressures ' -- - - - --- n l+ I, Advanced GeoEnvironmental,Inc 1 V ' �Iz r16