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Site No: 11792
<br /> (Table C-3). Benzene concentrations (up to 33 ppb) were detected in the same two
<br /> wells. Ethylbenzene (2 ppb) and total xylenes (1.5 ppb) were also detected in the water
<br /> sample from well MW-3. Chloroform (0.09 ppb) and zinc (0.02 ppm) were detected in
<br /> the well MW-4 sample.
<br /> In February 1991, IT documented the removal of three 10,000-gallon gasoline tanks,
<br /> three 3,000-gallon motor oil tanks, and one 3,000-gallon waste oil tank (IT, 1991a).
<br /> Before these tanks were removed, monitoring well MW-2 was destroyed because it was
<br /> within the area excavated for the new fuel UST complex (Figure C-3). IT (1991a) noted
<br /> that the fuel USTs appeared in excellent condition, and the oil USTs appeared corroded,
<br /> but intact. Groundwater was not encountered in the excavations. IT (1991a) also stated
<br /> that gasoline appeared to be widespread in the fuel UST excavation and absent in the
<br /> motor oil and used oil UST excavation. Fuel contamination was "apparent" in the fuel
<br /> pipe trenches (IT, 1991a). Soil samples were taken at a depth of 2 feet beneath each
<br /> UST (14 samples total), at a depth of 2 feet beneath the fuel or oil piping (6 samples
<br /> total.), and at the corners, bottom, and side walls of the "new" excavation (7 samples
<br /> total; Figure C-4). Twenty-four composite soil samples were also collected from three
<br /> stockpiles (new UST, fuel piping and UST, and oil piping and UST) on site
<br /> (Figure C-4).
<br /> The samples were analyzed for TPH-G, BTEX, EDB, Pb, TPH-D, chlorinated
<br /> hydrocarbons, PCBs, Cd, Cr, 2n, Pb, Ni, and oil and grease, depending on where they
<br /> were collected (Table C4). TPH-G (up to 3,500 ppm) was detected in samples taken
<br /> from the fuel UST excavation. Concentrations were greatest along the southwestern
<br /> margin of the excavation where fuel pipes exited the excavation. BTEX (up to 3.6 ppm
<br /> benzene, 80 ppm toluene, 130 ppm ethylbenzene, and 520 total xylenes) was also
<br /> detected in the fuel UST excavation. Total lead (up to 9.5 ppm) was detected in samples
<br /> from beneath the former leaded gasoline UST. EDB (up to 6.2 ppm) was detected in the
<br /> same samples. TPH-D (29 ppm) was detected in a sample taken from the motor oil UST
<br /> complex. Heavy metals (up to 5.2 ppm lead, 28.9 ppm copper, 34.7 ppm nickel, and
<br /> 38.2 ppm zinc) were detected in soil samples from beneath the used oil tank. TPH-G
<br /> (up to 677 ppm) was detected along the piping from the fuel USTs. BTEX (up to
<br /> 2.4 ppm benzene, 16.3 ppm toluene, 4.0 ppm ethylbenzene, and 184 ppm xylenes) was
<br /> also detected in samples taken beneath the piping from the fuel USTs. Soil samples
<br /> taken from the new excavation detected total lead concentrations up to 6.8 ppm. TPH-G,
<br /> TPH-D, BTEX and EDB were not detected in samples from the new excavation.
<br /> Composite samples taken from the fuel piping and UST stockpile detected TPH-G up to
<br /> 3,100 ppm (Table C-4). BTEX (up to 0.72 ppm benzene, 22.0 ppm toluene, 16.0 ppm
<br /> ethylbenzene, and 500 ppm xylenes) was also detected. Samples taken from the oil
<br /> piping and UST stockpile detected TPH-D (up to 73 ppm) and oil and grease (up to
<br /> BrrOS/RPT/11192RPi.d07-94/LAM/1b:5 Rev.0, 12/27/94
<br /> 09s2-090.03 3
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