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<br /> Mr. M. Scott Mansholt-CEMC
<br /> rl Third Quarter 2005 Groundwater Monitoring and Sampling Report October 25,2005
<br /> US Can-Welty Road, Vernalis,CA Page 3 of 6
<br /> ri ethylbenzene, and xylenes(BTEX),and trichloroethene(TCE)were the main compounds
<br /> detected in the soil samples. Concentrations of these constituents varied from 0.4 to 16 mg/kg.
<br /> WHF, Inc. and SEMCO excavated an exploratory trench to 19 feet bgs (near the northeastern side
<br /> of the can fabrication plant)and collected one soil sample at 14 feet bgs. Total petroleum
<br /> hydrocarbons as diesel(TPHd), TPH as motor oil (TPHmo), BTEX, and TCE were detected in
<br /> this sample. Concentrations of TPHd and TPHmo were 8,600 and 3,400 mg/kg, respectively.
<br /> The contents of the wastelbum pit were also removed.
<br /> 1996 Site Investigations. On March 6, 1996, WHF, Inc. advanced six hand borings (RB-1
<br /> through RB-6) to a depth of 2.5 feet bgs in the vicinity of the waste/bum pit area. TPHmo was
<br /> detected in four soil samples (RB-1, RB-2, RB-3, and RB-5). Concentrations of TPHmo ranged
<br /> from 50 to 80 mg/kg.
<br /> Three soil borings(SB-1, SB-2, and SB-3) and one monitoring well (MW-1) were installed by
<br /> Geological Technics in the vicinity of the former condensate pipe outlet. TPH as gasoline
<br /> ` (TPHg),TPHd, and TPHmo were detected in the majority of the soil samples. Concentrations
<br /> ranged from less than 1 to 11,300 mg/kg.
<br /> 1997 Site Investigation. On February 27, 1997, three cone penetration test(CPT)borings
<br /> (CPT-1, CPT-2, and CPT-3)were advanced by Gregg Drilling under the supervision of Radian
<br /> International (Radian). Groundwater samples were collected during this investigation in order to
<br /> determine if TCE had impacted groundwater. Groundwater samples were collected at depths of
<br /> 35 and 50 feet bgs. No TCE was detected in any of the samples. Cis-1-2-dichloroethene(C-1-2-
<br /> DCE), a degradation product of TCE, was detected in one of the groundwater samples analyzed.
<br /> 1998 Site Investigation. On July 15, 22, and 23, 1998, six soil borings (B-1 through B-6)and
<br /> r three monitoring wells (MW-2, MW-3, and MW4)were installed at the site by Radian.
<br /> Concentrations exceeding 100 mg/kg of TPHg, TPHd, and TPHmo were detected in borings B-1,
<br /> B4, B-5, B-6, and well boring MW-2. Concentrations were detected up to 21,000 mg/kg in these
<br /> samples.
<br /> 1999 Site Investigation. On November 9 and 11, 1999, Gregg Drilling, under the supervision of
<br /> Geomatrix, advanced seven soil borings(GMX-1 through GMX-7) for soil and groundwater
<br /> samples. TPH as crude oil(TPHc)were detected at a concentration of 10,000 mg/kg in one soil
<br /> sample collected at 37 feet bgs from GMX-3. TPHg and TPHd were detected in groundwater
<br /> sample GMX-6 at concentrations of 110 and 92 micrograms per liter(pg/L), respectively.
<br /> .. 2002 Site Investigation. On May 20 and 21, 2002, Gregg Drilling, under the supervision of
<br /> Geomatrix, advanced three soil borings (GMX-8, GMX-9, and GMX-1B) for additional soil
<br /> samples. TPHc were detected in borings GMX-8 and GMX-1B at maximum concentrations of
<br /> 8,000 and 5,100 mg/kg,respectively.
<br /> 2003 Site Investigation. On August 4 and 5, 2003,Gregg Drilling, under the supervision of
<br /> Geomatrix, advanced three soil borings (GMX-10, GMX-11,and GMX-12) for soil and
<br /> groundwater samples. TPHc were detected in the soil sample from boring GMX-12 collected at
<br /> 41.5 feet bgs at a concentration of 15,000 mg/kg. TPHd were detected in all groundwater
<br /> samples collected from GMX-10, GMX-11, and GMX-12 at concentrations of 210, 3,600, and
<br /> 110µg/L,respectively.
<br /> PETROLEUM DISTRIBUTION IN GROUNDWATER
<br /> y During the third quarter monitoring and sampling event, separate-phase oil(SPO)was observed
<br /> in well MW-I and a sheen on MW-2. Dissolved-phase crude oil is indicated by TPHd analyses.
<br /> SAIC began quarterly monitoring of the site in April 2005. During the April 2005 monitoring
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