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<br />' 20023 d Quarter Groundwater Report
<br /> • Frontier Transportation
<br />' 1102-194
<br /> November 26, 2002
<br /> Page 1
<br /> 1.0) INTRODUCTION
<br /> Blakely Environmental Investigations, Inc (BEII) was contracted by Frontier
<br />' Transportation, Inc to report the 2002 third quarter groundwater monitoring results at the
<br /> Frontier Transport facility, 425 Larch Road, Tracy, California (See Figure 1, Site Location Map)
<br /> The San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD),
<br /> Carrol Oz, Senior RENS requested quarterly groundwater monitoring on September 8, 1999
<br /> 2.0) SITE LOCATION AND HISTORY
<br /> The site is located in Tracy, California at 425 Larch Road in the northwest quarter of
<br /> section 16, Township 2 South, kange 5 East, Mount Diablo Baseline at Meridian The site
<br /> consists of a trucking facility with one metal frame building and all parking and work areas
<br /> capped by cement and/or asphalt The site is located in an industrial park
<br />' Six (6) underground fuel storage tanks (USTs), three diesel tanks located northeast of the
<br /> terminal and three gasoline tanks located southeast of the terminal, were removed from the site
<br />� . on July 21, 1995 Soil sample analysis identified total petroleum hydrocarbons as gasoline
<br /> (TPH-g) and total petroleum hydrocarbons as diesel (TPH-d) in the gasoline tank excavation at
<br /> maximum concentrations of 9,800 mg/kg and 120 mg/kg, respectively Groundwater sample
<br /> analysis identified dissolved phase TPH d in the`diesel excavation pat at a maximum
<br /> concentration of 1,200 µg/L ' ' k r
<br /> In August of 1996, Twinning Laboratories, Inc (Twinning) advanced six vertical soil
<br /> borings (B-1, B-2, B-3, MW-IRA, MW-IRB, and MW-2RA) and one angle boring (B-4) to
<br /> depths between 10 5' and 12 5' below grade (bg) to assess subsurface conditions near the
<br /> northeastern excavation In addition, two hand augers (S-1 and S-2) were advanced to 3'bg to
<br /> assess subsurface conditions beneath the dispenser and product lines and three groundwater
<br /> monitoring wells, MW-1 through MW-3, were drilled to approximately 25' bg to assess the
<br /> subsurface water beneath the site Initial subsurface water was encountered at 10 5' bg Boring
<br /> B-4 located northwest of the former USTs identified maximum TPH-g, BTEX (Benzene,
<br /> Toluene, Ethylbenzene, and Xylene), and MTBE (Methyl-tert Butyl Ether) as 1,300 mg/kg, 180 7
<br /> mg/kg, and 110 mg/kg, respectively at 10 2' bg j
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<br /> I Groundwater samples were collected from monitoring wells MW-1, MW-2, and MW-3
<br /> on August 30, 1996 and April 21, 1997 by Twinning Results are presented in Table 1
<br /> r ,
<br /> In January of 1998, BEII advanced four,(4) groundwater monitoring wells (MW-4
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