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s . 16 August 2001 AGE-NC Project No 97-0312 Page 4 of 20 - indicated the presence of hydrocarbons TPH-g, TPH-d and benzene were detected at ' concentrations of 330 gg/l, 880 µg11 and 4 5 µg/l,respectively w n - September/December 1992 : Ground water monitoring was performed during the third and fourth quarter of'1992 at the site High concentrations of petroleum hydrocarbons were . reported in the ground water samples during both monitoring events According to ESE documents, free product was pumped from the well prior to sampling during both quarters • 1993 - The well box for UST-1 was found to be'in poor condition, and evidence of infiltration of water and fuel from the surface was noted, floating free product was encountered in USTA Ground water monitoring and sampling was performed during the second,third and fourth quarters of 1993 Additionally,'weekly ground water extraction was performed as interim remediation It was reported by ESE that water quality improved due to pumping activities Interim pumping was reduced to biweekly beginning in 1994- • March 19951 Three additional ground water monitoring wells (UST-2, UST-3 and UST-4) were installed on-site in March 1995 to maximum depths of 85 feet bsg, well screens were recorded between 65 and 85 feet bsg Laboratory analysis of soil samples collected from the pilot borings detected petroleum hydrocarbons in samples from boring UST-4 at depths of � . 25 feet, 30 feet,35 feet,40 feet and 45 feet bsg Hydrocarbon,compounds were not detected in any of the soil samples analyzed from borings UST-2 and UST-3, defining the maximum horizontal extent of the plume of impacted soil in the northwest and southeast-directions ' Initial ground water sampling during the second quarter of 1995 contained low concentrations of TPH-g and TPH-d in samples collected from UST-4 r • June'1997 - One ground water monitoring well (UST-5) and soil vapor well (VP-1) were ' iiistalled on-site to a depth of approximately 74 5 feet`bsg, the well screen of UST-5 was recorded between 54 5 feet and 74 5 feet bsg Laboratory analysis of soil samples collected ' from boring UST-5 detected petroleum hydrocarbons at depths between 5 feet and 55 feet bsg r •` September 1997 - Six product USTs were removed from the site A total of mile UST soil ' samples(TI-E-through T6-17) and thirteen piping/dispenser soil samples(P1 through P13) were collected and analyzed Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) were detected in the samples collected beneath the UST's at ' concentrations as high as 2,500 mg/kg and 32,000 mg/kg, respectively TPH-g and TPH-d were detected in piping/dispenser samples at'concentrations as high as 1,200 mg/kg and 16,000 mg/kg, respectivelyf(Table 3) Excavation oapproximately 400 cube ` aids of ' hydrocarbon-impacted soil was performed after removal of the USTs Excavated soil was stockpiled on site' Procedures and findings were summarized in the,UST Removal Report- September 1997 prepared by AGE Analytical results of soil samples collected during the ' UST/product piping removal are summarized in Tables 4 and 5 Soil sample locations are, illustrated in Figure 3 F Advanced GcoEnvIronmental,lnc n r