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Mr. James L.L. Barton,
<br /> ARCADIS P.G.
<br /> May 29, 2009
<br /> storage tanks(USTs), three pump islands, and ten active and two abandoned
<br /> groundwater monitoring wells.
<br /> Remedial Background
<br /> Between June 24 and August 5, 1990,four groundwater monitoring wells(MW-2
<br /> through MW-5)were installed on site. Soil samples from each boring were analyzed
<br /> at 5.5 feet, 15.5 feet, and 50.5 feet below ground surface(bgs). The soil samples
<br /> from all four borings were analyzed for total petroleum hydrocarbons as gasoline
<br /> (TPH-G)by Environmental Protection Agency(EPA)Method 8015,for benzene,
<br /> toluene, ethylbenzene, and total xylenes by EPA Method 602,and for ethyl
<br /> dibromide(EDB)by EPA Method 504. Samples from:monitoring well MW-5 were
<br /> analyzed for the presence of volatile organic compounds.(VOCs)by Method 624.'No
<br /> petroleum hydrocarbons were detected in the soil and groundwater samples
<br /> collected from any of the borings.The presence of.VOCs were limited to 7 parts per
<br /> billion(ppb)of 1,2-dichloroethane(1,2-DCA)detected in the`groundwater samples
<br /> collected from monitoring well MW-5.
<br /> From December 1997 to January 1998,three hoists,two waste oil storage tanks, and
<br /> the associated product piping were removed during a station renovation.At this time,
<br /> WOT-1 (1,000-gallon capacity)was removed.A previously unknown waste oil tank
<br /> (WOT-2)and a 6-inch steel well(OW-1)were discovered immediately south of the
<br /> northeast canopy footing. Soil and groundwater samples were submitted for analysis
<br /> by EPA Methods 8015, 8020, 8240,624, 8260,908, 910, 7520,7130, 7190, 7420,
<br /> and 7950. Analysis of soil samples collected from the WOT-1 excavation pit indicated
<br /> that petroleum hydrocarbons and fuel oxygenate impacts to soil extended no deeper
<br /> than 17.5 feet bgs.The WOT-1 soil samples contained concentrations of TPH-G at
<br /> 110 parts per million (ppm), total petroleum hydrocarbons as diesel(TPH-D)at 4,900
<br /> ppm, total petroleum hydrocarbons as oil(TPH-O)at 7,400,ppm,and total BTEX at
<br /> 8.4 ppm.The presence of chlorinated solvents were limited-to 2.2 ppm of cis-1,2-
<br /> dichloroethene(cis-1,2-DCE)and 1.5 ppm tetrachloroethene(PCE).Analysis of soil
<br /> samples collected from the WOT-2 excavation pit contained no detectable
<br /> concentrations of waste oil constituents.Additionally, no other waste oil tank
<br /> constituents analyzed, such as chromium,cadmium, lead, nickel, and zinc(CAM 5
<br /> Metals)or polychlorinated biphenols(PCBs),were detected from either excavation
<br /> pit.
<br /> In June 1998 Levine-Fricke-Recon, Inc.(LFR), on behalf of Lincoln Properties Ltd.,
<br /> installed two groundwater extraction wells(GWE-007A, GWE-008A)and associated
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