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15 November 2005
<br /> • AGE-NC Project No 95-0130
<br /> Page 5 of 10
<br /> the Inlet of the P&T remediation system The P&T remediation system consisted of
<br /> transferring petroleum-Impacted water through to a 5,000-gallon holding tank, from the
<br /> holding tank, water was treated by passing through a low profile air stripper, then through
<br /> four 2,000 pound media vessels containing liquid phase granular activated carbon (GAC)
<br /> Following treatment,water was discharged underground via 1-inch diameter PVC piping to
<br /> the City of Stockton sewer system,discharge piping is connected to a sewer clean-out located
<br /> in a east section of the site, approximately 100 feet east-northeast of the pump-and-treat
<br /> system Initial influent P&T samples detected TPH-g at concentrations as high as 69,000
<br /> µg/l, BTEX compounds as high as 11,000 µg/1 benzene, 8,800 µg/l toluene, 3,100 µg/1
<br /> ethylbenzene, 16,000 µg/l xylenes and MTBE as high as 7,100 µg/1 Results of the
<br /> November 2004 P&T interim remediation start-up were reported in Quarterly Report -
<br /> Fourth Quarter 2004, dated 30 March 2005, prepared by AGE
<br /> 2 4 GROUND WATER MONITORING PROGRAM
<br /> Between January 1995 and October 2005, forty ground water monitoring events have been
<br /> performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground water
<br /> and to characterize ground water flow direction and gradient on the site Generally, TPH-g was
<br /> detected in water samples collected from wells MW-1, MW-2, MW-3, MW-5, MW-6 (A, B, C, D
<br /> and E), MW-7 (B, C, D and E), MW-8,VW-1C, VW-2A and VW-3A at concentrations as high as
<br /> 390,000 µg/1 TPH-g,BTEX compounds as high as 92,000 µg/l and MTBE at concentrations as high
<br /> as 440,000 µg/l (Table 3), however, recent ground water monitoring events conducted from wells
<br /> MW-1, MW-2, MW-3 and MW-5 did not detect any petroleum constituents in ground water, and
<br /> may be due to the on-going ground water pump-and-treat and/or soil vapor extraction activities being
<br /> performed at the site
<br /> Low concentrations of tert-amyl methyl ether (TAME), tert butanol (TBA), ethylene dibromide
<br /> (EDB) and 1,2-dichloroethane (1,2-DCA) have been detected from wells MW-1, MW-2, MW-3,
<br /> MW-6(B and C),MW-7B,VW-1 (B and C),VW-2 (B and C)and VW-3A on isolated occurrences
<br /> Generally,the depths to ground water in wells MW-1 through MW-8 were measured between 36 and
<br /> 60 feet bsg, ground water elevation at the site were calculated between 20 and 44 feet below mean
<br /> sea level Between January 1995 and August 2001,groundwater elevations generally increased from
<br /> 44 feet to 23 feet below MSL,however,since August 2001 and present day,ground water elevations
<br /> have generally fluctuated between 24 feet and 29 feet below MSL The general ground water flow
<br /> direction has generally been towards the northeast and east
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<br /> Advanced GeoEnvironmental,Inc
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