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' Site Background Information/SCM Former MBP -Mossdale AGE NC Project No 99-0570 ' Page 2 of 5 ' UNDERGROUND STORAGE TANK REMOVAL On 05 February 1998, one 10,000-gallon UST, one 8,000-gallon diesel UST, and one 8,000-gallon ' gasoline UST were removed from the site, the approximate locations of the former USTs, product piping, and dispensers are shown on Figure 2 of the attached report Soil samples were collected at the UST locations, dispensers, and product lines Laboratory analytical results detected total ' petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d), benzene, toluene, ethylbenzene, and total xylenes (BTEX), and fuel additives in the soil samples collected from the UST excavations and dispenser areas,the latter exhibited significant staining and hydrocarbon odor ' Onlyone UST removal sampling had detectable concentrations of hydrocarbons,yet all samples had P moderate detections of fuel additives High concentrations of hydrocarbons and low concentrations ' of fuel additives were generally detected in soil samples D2,D3,and D5 from the former dispenser areas The dispenser soil samples exhibited significant staining and hydrocarbon odor Analytical ' results are summarized in Table 1 of this appendix . PREVIOUS SITE ASSESSMENT On 11 August 1999, 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 (EXE1) 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,(aHAS c�e]},�atcn of 11,000 mg/kg BTEX compounds were detected at concentrations as high as� Wkg JThe 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 EXE/ The stockpiled soil was impacted by low to moderate concentrations of petroleum hydrocarbons and fuel additives The results are summarized in Table 1 of this appendix ' On 29 October and 01 November 1999,AGE advanced eight soil probe borings to a depth of 30 feet below surface grade (bsg) at the site to obtain soil and grab ground water samples TPH-g, TPH-d, Advanced GeoEnvironmental,Inc 1