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Soil sampling conducted around the former UST location has identified high TPHg concentrations in soil above the water table. These TPHg results range from 8,100 milligram per kilogram(mg/kg)in boring 1613-8 (Treadwell&Rollo, 2004)up to 14,000 mg/kg in VW5 (AGE, 1999)at a depth of 10 to l 1 feet bgs. These results indicate that a continuing source of contamination was present in this area. Previous soil sampling results also indicate that high TPHg concentrations(9,000 mg/kg in VW5 at 25 feet bgs and 8,300 mg/kg in SW21 at 35 feet bgs) exist below the current groundwater table in this area(AGE, 1999). This is likely residual contamination from when the groundwater table was deeper than 25 feet bgs. As previously reported in the 2004 Workplan,boring logs indicate that separate phase product may be present in soil and groundwater within the former UST location extending to at least 16B-8 to the west and MW-3 to the east. Significant,but lower TPHg concentrations are present in soil(at the groundwater interface)and/or in groundwater in borings 16B-10 to the south,and in boring 16B-713 and well EW-4 to the north. TPHg and benzene concentrations in groundwater drop off beyond this area in borings 16B-9 and 1613-11, and appear to be related to the"smear zone"or the depth interval of groundwater table fluctuation. This data suggested that there has been a continuing source of gasoline contamination at the former Tank No.7 location,and that free product may have been present. This would account for why years of in-situ remediation work has not resulted in more significant decreases in groundwater concentrations at the Tank No.7 location,and may indicate that continued in-situ remediation may not effectively mitigate the groundwater contamination. 4.0 SITE REMEDIATION The Site excavation activities are described in Sections 4.1 to 4.7. Deviations from the 2004 Workplan are presented in Section 4.2. 25971021.DJS 4 18 November 2004