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CAMBRIA Roseville, California performed over-excavation beneath the dispenser area and UST complex and collected additional soil samples One soil sample collected from the bottom of the UST excavation contained 1,000 parts per million (ppm) total petroleum hydrocarbons as gasoline (TPHg), and one soil sample collected from the northern sidewall of the dispenser excavation contained 2 7 ppm TPHg Complete results of the UST removal are documented in the Fugro April 19, 1995 Underground Storage Tank Closure Report 1996 Soil Borings During February 1996,Enviros, Inc (Enviros)drilled two GeoProbeo borings (GP-1 and GP-2) in the vicinity of the UST complex to investigate the extent of petroleum hydrocarbons detected during the December 1994 tank removal activities Enviros drilled one angle boring (GP-2) beneath the UST complex and one vertical boring (GP-1) adjacent to the UST complex Soil samples collected from the two borings did not contain detectable concentrations of petroleum hydrocarbons but did contain MTBE at concentrations up to 29 ppm This investigation is described in Enviros' May 8, 1996 Soil Boring Installation Report 1999 Soil Borings. During January 1999, Cambria drilled five soil borings (SB-1 through SB-5) in the vicinity of the UST complex TPHg was only detected in boring SB-3 at a concentration of 3 17 ppm No benzene was detected in any of the soil borings MTBE was detected (by EPA Method 8260) in all borings at concentrations ranging from 0 00807 to 92 9 ppm Groundwater samples were collected from borings SB-3 and SB4 They contained 46,000 and 6,610 parts per billion (ppb) TPHg, 243 and 63 6 ppb benzene, and 28,000 and 8,050 ppb MTBE, respectively These results are summarized in Cambria's June 9, 1999 Site Investigation Report i 1999 Well Installation. During November 1999, Cambria drilled four soil borings (GP-3 through GP-6) and installed three groundwater monitoring wells (MW-1, MW-2, and MW-3) at this site The soil borings were drilled in the vicinity of the dispenser islands to determine if this was the source area Analytical data collected from the borings suggest the dispenser islands were not the source area The monitoring wells were installed around the UST complex (Figure 2) Groundwater samples collected from these wells contained TPHg, benzene, and MTBE Analytical data from these wells and from previous soil borings drilled in the UST area suggest that this is likely the primary source area for petroleum hydrocarbons and MTBE detected in groundwater beneath this site The findings of this investigation are documented in Cambria's February 10, 2000 Site InvestigationlFourth Quarter 1999 Groundwater Monitoring Report 2000 Hoist and Waste Oil UST Removal. During November 2000, one 550-gallon waste oil UST and two hydraulic hoists were removed Cambria collected one soil sample from beneath . the waste oil tank and one sample beneath each hoist No petroleum hydrocarbons, fuel 0955 2