ARCHIVED REPORTS_XR0004943 - Laserfiche WebLink

Home Browse Search

Appendix A . AGE NC Project No 99-0570 IPage 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 of Figure 2 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 ' Only one UST removal sampling had detectable concentrations of hydrocarbons,yet all samples had moderate detections of fuel additives High concentrations of hydrocarbons and low concentrations rof 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 PREVIOUS SITE ASSESSMENT I . On 11 August 1999,an additional 150 cubic yards of significantly petroleum hydrocarbon-impacted soil was removed from 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 I 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, BTEX,and methyl tertiary-butyl ether(MTBE)were detected in soil samples analyzed at maximum I concentrations of 49 milligrams per kilogram(mg/kg), 180 mg/kg,0 36 mg/kg, and 78 micrograms per kilograms(pg/kg),respectively Laboratory analysis of grab ground water samples indicated that the highest concentrations of TPH-g, TPH-d, BTEX, and MTBE were in the vicinity of the 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 only one of eleven soil samples, at similar concentrations of 170 mg/kg, in addition, BTEX-a-n—d {� ' several additional volatile organic compounds were detected at concentrations up to 0 44 mg/kg TPH-g,TPH-d,and BTEX were esected n tavo ground water samples collected on 03 October 2000 a: at maximum concentrations oM_ rgllr2; 8 n/l,and 160µg/1,respectively,in addition,MTBE was detected in three ground water samples at a maximum concentration of 170 µg/1 Advanced GeoEnvironmental,Inc