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CLEARWATER
<br /> {� G R O U P, I N C
<br /> Environmental Services
<br /> GROUNDWATER MONITORING REPORT
<br /> SECOND QUARTER 1999
<br /> Barnes Trucking Facility
<br /> 1817 South Fresno Avenue,
<br /> Stockton, California
<br /> August 24,1999
<br /> BACKGROUND
<br /> The Barnes Trucking facility is located on the southwest corner of the intersection of Charter Way
<br /> (State Highway 4) and South Fresno Avenue (Figure 1) The property is located approximately 15
<br /> miles south of the Port of Stockton Turning Basun and 0 9 mile east of the San Joaquin River (Figure 2)
<br /> Currently, the site is used as a truck dispatch center and parking area There are no fuel dispensing
<br /> facilities operating at the site
<br /> In letters dated September 18, 1992 and April 30, 1996, the San Joaquin County Public Health Services,
<br /> Environmental Health Division (EHD) indicated that additional investigation of this site was
<br /> required because petroleum hydrocarbons were detected in soil samples collected from an underground
<br /> storage tank (UST) excavation According to an April 30, 1996 EHD letter, two USTs were removed from
<br /> the site on June 15, 1992 Both USTs were 10,000-gallon capacity tanks that had been used to store fuel
<br /> ' Four soil samples were collected from the bottom of the excavation at a depth of approximately 16 feet
<br /> below ground surface (bgs) Soil samples were analyzed for total petroleum hydrocarbons as gasoline
<br /> (TPHg) as diesel fuel (TPHd), as kerosene (TPHk), and as oil (TPHo) Samples were also analyzed for
<br /> benzene, toluene, ethvlbenzene, and xylenes (BTEX) The highest concentrations of TPHg, TPHd, and
<br /> BTEX were detected at 5,700 milligrams per kilogram (mg/kg) TPHg, 50 mg/kg TPHd, and 48 mg/kg
<br /> benzene TPHk,and TPHo were not detected in any of the four samples
<br /> On September 25, 1997, Clearwater Group, Inc (Clearwater) supervised the drilling of six soil borings to
<br /> depths from 32 to 38 feet bgs Three of the borings were converted to groundwater monitoring wells
<br /> (MW-1, MW-2, MW-3) Soil samples collected from four of the six borings contained detectable
<br /> concentrations of petroleum hydrocarbons The highest concentrations of TPHg(570 mg/kg) and benzene
<br /> (4 0 mg/kg) were detected in the sample from SB-2 at a depth of 25 feet bgs Groundwater samples
<br /> collected September 29, 1997 from all three monitoring wells contained detectable concentrations of
<br /> dissolved petroleum hydrocarbons The highest concentrations of TPHg (32,000 micrograms per liter
<br /> [pg/Ll) and benzene (2,200 lig/L) were detected in the sample from monitoring well N4W-1 Low
<br /> concentrations of TPHd were detected in soil samples from SB-5 (11 mg/kg) and SB-6 (2 mg/kg), and in
<br /> the groundwater sample from MW-1 (300 pg/L),however, subsequent groundwater sample results have
<br /> been non-detect for all three wells, and with approval from the EHD, analysis for TPHd has been
<br /> discontinued Results of these efforts were presented in Clearwater's Subsurface Investzgatzon Report,
<br /> dated November 20, 1997,
<br /> Based on these initial investigation results, the EHD requested monitoring wells be installed to better
<br /> define the areal extent of soil and groundwater contamination After discussion with Lori Duncan of the
<br /> EHD, Clearwater submitted the Workplan for Site Investigation dated November 18, 1998 An
<br /> addendum to the workplan, dated December 10, 1998 was submitted in response to EHD comments The
<br /> Workplan and addendum were approved by the EHD on December 15, 1998
<br /> 520 Third Street,Suite 104 • Oakland,Cahfomia 94607 + Telephone 510-893-5160 • Fax 510-893-59.17
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