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Tosco Marketing Company `oe 2
<br /> Tosco(Former BP)#11193 3202 West Hammer Lane Stockton CA October 29.2001
<br /> (S-21.3-132), toluene at 0.0200 ppm (S-20.0-131), ethylbenzene at 0.0180 ppm (S-21.3-
<br /> 132), and total xylenes at 0.0240 ppm (S-21.3-132). Gasoline range total petroleum
<br /> hydrocarbons (TPHg) and diesel range total petroleum hydrocarbons (TPHd) were not
<br /> detected above laboratory detection limits. Laboratory analytical results for groundwater
<br /> detected maximum concentrations of TPHg at 2,200 parts per billion (ppb) (MW-1),
<br /> benzene at 120 ppb (MW-2), toluene at 15 ppb (MW-1), ethylbenzene at 1.0 ppb (MW-
<br /> 2), and total xylenes at 24 ppb (MW-2). TPHd was not detected above laboratory
<br /> detection limits (RESNA, 1993).
<br /> In March of 1994, Alisto conducted a supplemental subsurface investigation by drilling
<br /> and installing three groundwater monitoring wells (MW-5 through MW-7) to total
<br /> depths of 31 to 32 feet bgs. Groundwater Monitoring Well MW-5 was installed on the
<br /> northeast corner of the property, Well MW-6 was installed in an alley west of Kelly
<br /> Drive, and MW-7 was installed on the north side of West Hammer Lane. Laboratory
<br /> analysis of soil samples detected maximum concentrations of benzene at 0.13 ppm
<br /> (MW-5-16'), toluene at 0.67 ppm (MW-6-16'), and total xylenes at 0.015 ppm
<br /> (MW-5-16'). TPHg and TPHd were not detected above laboratory detection limits
<br /> (EMCON, 1994).
<br /> On November 22, 1994, EMCON conducted a supplemental site assessment consisting
<br /> of collecting two grab soil samples (TD-2 and TD-3)below the eastern fuel dispensers at
<br /> the north and south dispensers, drilling of two soil borings (THP-1, THP-2) to total
<br /> depths of 26.5 feet bgs, and the drilling and installation of Vapor Extraction Well VW-1
<br /> to a total depth of 17 feet bgs. Soil and hydropunch groundwater samples were collected
<br /> and analyzed from borings THP-1 and THP-2. Laboratory analysis of soil samples TD-2
<br /> and TD-3 detected maximum concentrations of TPHg at 2,100 ppm (TD-2), toluene at
<br /> 3.5 ppm (TD-3), ethylbenzene at 18 ppm(TD-3), and total xylenes at 110 ppm (TD-3).
<br /> TPHd, oil range total petroleum hydrocarbons (TPH-O), and benzene were not detected
<br /> above laboratory detection limits. Laboratory analysis of soil samples from borings
<br /> THP-1 and THP-2 detected maximum concentrations of TPHd at 1 ppm (THP1S-10)
<br /> and benzene at 0.03 ppm (THP@S-15). TPHg, TPH-O, toluene, ethylbenzene, and total
<br /> xylenes were not detected above laboratory detection limits. Laboratory analysis of
<br /> groundwater samples from borings THP-1 and THP-2 detected maximum concentrations
<br /> of TPHg at 6,900 ppb (THP2W-21), TPHd at 840 ppb (THP2W-21), benzene at 1,900
<br /> ppb (THP2W-21), and total xylenes at 77 ppb(THP2W-21). TPH-O, benzene toluene,
<br /> ethylbenzene, and Halogenated Volatile Organic Compounds (HVOC's) were not
<br /> detected above laboratory detection limits (EMCON, 1994).
<br /> On December 10 through 22, 1998, Gettler-Ryan Incorporated (GR) supervised the
<br /> removal of two 10,000 gallon and one 8,000 gallon single-walled UST,dispensers, and
<br /> associated product dispenser piping. Laboratory analysis of soil samples collected from
<br /> the UST excavation detected maximum concentrations of TPHg at 31 ppm (3W),
<br /> benzene at 0.27 ppm (3W), and Methyl-tert Butyl Ether (MtBE) at 80 ppm (3E).
<br /> Laboratory analysis of soil samples collected from the beneath the dispensers and
<br /> product piping detected maximum concentrations of TPHg at 1,600 ppm (D1) and MtBE
<br /> at 1.8 ppm (133). Additionally, approximately 15,000 gallons of water was removed
<br /> from the UST excavation during the installation of the new USTs. Laboratory analysis
<br /> TOSCO 11193/pilottest-dualphase
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