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<br /> Appendix A
<br /> • AGE NC Project No 99-0570
<br />' Page 2 of 5
<br />' UNDERGROUND STORAGE TANK REMOVAL
<br /> On 05 February 1998,one 10,000-gallon UST, one 8,000-gallon diesel UST, and one 8,000-gallon
<br />' gasoline UST were removed from the site, the approximate locations of the former USTs, product
<br /> piping, and dispensers are shown of Figure 2 Soil samples were collected at the UST locations,
<br /> dispensers, and product lines Laboratory analytical results detected total petroleum hydrocarbons
<br />' quantified as gasoline and diesel (TPH-g and TPH-d), benzene, toluene, ethylbenzene, and total
<br /> xylenes (BTEX), and fuel additives in the soil samples collected from the UST excavations and
<br /> dispenser areas, the latter exhibited significant staining and hydrocarbon odor
<br />' Only one UST removal sampling had detectable concentrations of hydrocarbons,yet all samples had
<br /> moderate detections of fuel additives High concentrations of hydrocarbons and low concentrations
<br />' of fuel additives were generally detected in soil samples D2, D3,and D5 from the former dispenser
<br /> areas The dispenser soil samples exhibited significant staining and hydrocarbon odor
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<br /> PREVIOUS SITE ASSESSMENT
<br /> t • On 11 August 1999,an additional 150 cubic yards of significantly petroleum hydrocarbon-impacted
<br /> soil was removed from beneath the three former dispenser areas Laboratory analytical data
<br />' indicated a significant concentration of TPH-g,TPH-d,BTEX compounds,and fuel additives in the
<br /> soil samples collected
<br />' On 29 October and 01 November 1999,AGE advanced eight soil probe borings to a depth of 30 feet
<br /> below surface grade (bsg)at the site to obtain soil and grab ground water samples TPH-g, TPH-d,
<br /> BTEX,and methyl tertiary-butyl ether(MTBE)were detected in soil samples analyzed at maximum
<br />' concentrations of 49 milligrams per kilogram(mg/kg), 180 mg/kg,0 36 mg/kg,and 78 micrograms
<br /> per kilograms(pg/kg),respectively Laboratory analysis of grab groundwater samples indicated that
<br /> the highest concentrations of TPH-g, TPH-d, BTEX, and MTBE were in the vicinity of the former
<br />' dispenser islands Based on the data collected,the dispenser islands appear to be the primary source
<br /> of the hydrocarbon release
<br />' Ground water monitoring wells MW-1 through MW-5 were installed On 27 and 28 September 2000
<br /> and monitored and sampled on 03 October 2000 TPH-g and TPH-d compounds were detected in an 114
<br /> only one of eleven soil samples, at similar concentrations of 170 mg/kg, in addition, BTEand J--L n
<br />' several additional volatile organic compounds were detected at concentrations up to 0 44 mg/kg MIW-2'
<br /> TPH-g,TPH-d,and BTEX wWNWRg/l,
<br /> 1%9
<br /> detected irltwo ground water samples collected on 03 October 2000 g
<br /> at maximum concentrations o %0 pg/1,and 160µg/I,respectively,in addition,MTBE was
<br />' detected in three ground water samples at a maximum concentration of 170 µg/1
<br /> On 09 December 2003, three soil borings (CPT-1, CPT-2, and CPT-3) were advanced on-site
<br /> • utilizing cone penetrometer testing(CPT)technology to a total depth of approximately 110 feet bsg
<br /> Advanced GeoEnvironmental,Inc
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