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' 31 October 2005 AGE-NC Project No 03-1080 Page 3 of 10 Envirotech, Inc (Apex) residual mass balance calculations are provided in Appendix B ' During the last ground water monitoring event, conducted in November 199 5mn�rograms per liter(µg/1) 1,2-DCA and 5 5 µg11 MTBE were detected in monitoring well MW-1 5 �g/l 1,2-DCA ' and 16 µg11 MTBE were detected in ground water samples collected from monitoring well MW-2, 610 µg/i TPH-d, 0 72 µg/l toluene, 2 3 µg11 1,2-DCA, and 8 4 µg11 MTBE were detected in well MW-3, 3 2 µg/1 1,2-DCA and 5 6 µg11 MTBE were detected in ground water samples from monitoring well MW-4, and 5 1 µg/1 MTBE were detected in well MW-8 Analytical results of ground water samples collected from April 1992 to November 1997 are included in Appendix A ' On 29 August 1997, four confirmation soil borings(VB-1 through VB-4)were advanced on-site to 25 feet bsg Eight soil samples were analyzed, one of the soil samples, taken at 25 feet bsg (VB-2-25), detected 0 0017 milligrams per kilogram (mg/kg) 1,2-DCA A table summarizing ' confirmation soil boring analytical results is provided in Appendix C On 29 December 1998, a no further action letter was issued for the site by the EHD In a letter dated 31 December 1998 Apex reported that all on-and off-site ground water monitoring ' . wells MW-1 through MW-9 had been abandoned, and the remediation system and compound dismantled The approximate locations of former monitoring wells MW-1 through MW-9 and confirmation borings VB-1 through VB-4 are illustrated on Figure 2 ' In January 2003,AGE was present at the site during the UST system dispenser and piping excavation and upgrade activities,performed by Elite IV Contractors,Inc of Stockton,California Soil removed ' during the excavation was stockpiled on-site for characterization for soil disposal Soil samples were collected for laboratory analysis from the floor of the fuel dispenser and piping excavations, from a gravel pile, and from the soil stockpiles The laboratory analysis detected TPH-g and TPH-d, as well as volatile aromatic compounds ethylbenzene and xylenes in the sample collected from dispenser D1,TPH-d,toluene,and xylenes were also detected in the D4 sample In addition,the fuel additives MTBE and tertiary-butyl alcohol (TBA) were detected in the sample collected from soil ' stockpile 2A-213 The excavated soil was subsequently transported to Forward Landfill for disposal Analytical results are summarized in Table 1 ' On 02 and 03 August 2004, three soil probe borings (B 1 through 133)were advanced at the site by AGE utilizing a van-mounted Geoprobe 5400 direct-push probing unit, total boring depths were between 35 feet and 40 feet bsg A total of ten soil samples and three grab ground water samples ' were collected from borings B1 through B3 for laboratory analysis Petroleum hydrocarbons were detected in soil and ground water samples collected from boring B1, however, according to the analytical laboratory,the hydrocarbons were remnants of aged or degraded fuel TPH-g-and TPH-d- ' range hydrocarbons were detected in a soil sample collected from boring B 1 at 15 feet bsg(B1-15), . at concentrations of 250 mg/kg and 190 mg/kg, respectively, in addition, xylenes were detected in Advanced GeoEnvironmental,Inc