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LW L - 15 June 2009 ti,.r AGE-NC Project No.05-1306 tow Page 5 of 33 • April and June 2000 - six soil borings (SB-7 through SB-12) were advanced on-site, for 16" collection of soil and grab ground water samples. Additionally, three ground water monitoring wells (MW-4 through MW-6) were installed on-site to a depth of 25 feet bgs. Analytical results of soil samples reported TPH-d and TPH-g in pilot boring MW-4(MW-4 at 20.5 feet bgs)at concentrations of 1 100 mg/kg and 85 mg/kg,respectively.Benzene was reported in the grab ground water samples collected from boring SB-12 at 29 feet bgs and 49 feet bgs, at a concentration of 0.8 µg11. Analytical results of soil and grab water samples are summarized in Tables 1 and 3. In April 2004, H&A conducted an investigation to delineate the vertical and horizontal extent of petroleum hydrocarbon-impacted soil and ground water near the former UST excavation area. Ten soil borings (HA-1 through HA-9 and Tank-EX) were advanced for collection of soil and grab +" ground water samples. Additionally, one ground water monitoring well (MW-7)was installed at a depth of 35 feet bgs. Analytical results of soil samples reported TPH-d from borings HA-2,HA-8, HA-9, and Tank-EX. TPH-d was reported at a maximum concentration of 1,500 mg/kg (HA-9 at 25 feet bgs). TPH-g was reported in the soil samples collected from borings HA-8 and HA-9, at a maximum concentration of 660 mg/kg (HA-9 at 25 feet bgs). Grab ground water samples were collected from borings HA-1 through HA-7. TPH-d was reported in the grab groundwater samples collected from boring HA-2 at a concentration of 7,500 µg/l (HA-2 at 15 feet bgs). Between 2005 and 2008,AGE performed remedial activities consisting of excavation,installed four ground water monitoring wells, and advanced three soil-vapor borings and four CPT soil borings: • August 2005 - Monitoring well MW-2 was abandoned as part of over-excavation activities to remove hydrocarbon-impacted soil from the former UST. Monitoring well MW-2 was abandoned by over-drilling the well to total depth.To facilitate over-excavation,the well was �. backfilled to surface grade with Type I/H Portland cement. • September 2005 - The soil surrounding the former UST excavation was over-excavated to a depth of approximately 25 feet bgs. Approximately 963 cubic yards of petroleum hydrocarbon-impacted soil and 240 cubic yards of clean overburden were excavated from the site. Soil samples were collected from the floor of the over-excavation, impacted soil 60 stockpiles,and clean soil stockpiles(Figure 3).Three soil-water samples were collected from the floor of the over-excavation and one water sample was collected from the water holding tank. Analytical results of soil and water samples are summarized in Tables 2 and 4. The �. over-excavation was backfilled using a combination of pea-gravel,native clean soil removed from the over-excavation, and imported A/B baserock. Results of the investigation were detailed in the AGE-prepared Over-Excavation and Sampling Report-Former UST Area, dated 09 December 2005. 4 Advanced GeoEnviranmenkal,Inc. #r