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Site History
<br /> Canepa's Car Wash(Pacific Avenue)
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<br /> limits from 20 feet bgs to the capillary fringe. A summary of the soil and groundwater analytical data is
<br /> contained in Interim Status Report, Phase Il Investigation, by WHF. Based on the initial data, the vertical
<br /> and lateral limits of contamination were not sufficiently defined. WHF proposed the installation of four(4)
<br /> additional monitor wells (MW-5 through MW-8) to fully characterize the groundwater plume. The
<br /> PHS/EHD granted approval of the additional investigation on January 19, 1994. Between March 9 and 11,
<br /> 1994, WHF installed MW-5 through MW-8. TPH-G was detected in the soil sample collected from MW-6
<br /> at 50 and 55 feet bgs and from MW-7 at 50 feet bgs. TPH-G and BTEX were detected in groundwater
<br /> samples collected from MW-6, MW-7, and MW-8. A summary of the soil and groundwater analytical data
<br /> is contained in Phase H Site Characterization, by WHF. The wells were surveyed and groundwater
<br /> elevation measurements indicated that a groundwater mound existed beneath the site. This suggested that
<br /> recharge or leakage into the groundwater in the vicinity of MW-1 and MW-2 was occurring. Three
<br /> potential sources of recharge were identified: 1)the car wash water recycling pit system under the building,
<br /> 2) a leaking or broken sewer line that crosses the area, and 3) a leaking water supply line. An MBAS
<br /> (Methyl Blue Active Surfactants) test was conducted on groundwater samples collected at the site in July,
<br /> 1994,to investigate the presence of detergents. MBAS was not detected in the samples.
<br /> Aquifer testing(24-hour pump test)was conducted at the site by WHF on December 22 and 23, 1994. MW-
<br /> 1 was used as a pumping well, and MW-4, MW-6, MW-7, and MW-8 were used as observation wells. The
<br /> results indicated an optimum pumping rate of 5 gpm with an effective radius of 140 feet. Aquifer
<br /> permeability was estimated at I26 gpd/ft2.
<br /> Quarterly groundwater monitoring was conducted at the site by WHF from March, 1994, through June,
<br /> 1995. Historical groundwater analytical data indicated elevated concentrations of TPH-G and BTEX in
<br /> MW-1, MW-2, MW-6, and MW-7. Low concentrations of TPH-G and BTEX were detected in MW-3,
<br /> MW-4, MW-5, and MW-8. Condor has been conducting quarterly groundwater monitoring at the site since
<br /> August, 1996. Analyses of groundwater samples collected from selected SVE wells (SVE-1, 2, 3, 5, 7, 8,
<br /> and 9) indicated that high concentrations of TPH-G, BTEX, and MTBE were present in the former location
<br /> of the fuel dispenser islands. The groundwater table elevation has generally increased since quarterly
<br /> monitoring began in March 1994.
<br /> A site investigation was conducted by Condor Earth Technologies, Inc. (Condor) on July 31, 1996, at the
<br /> Canepa's Car Wash facility. The investigation included a review of existing investigative reports and an
<br /> evaluation of the existing SVE system located at the site. The fieldwork was conducted in accordance with
<br /> Condor's proposal for SVE evaluation, dated April 8, 1996, and the addendum to the proposal, dated May 2,
<br /> 1996. The subsequent report was titled Soil Vapor Extraction (SVE) System Evaluation, dated September
<br /> 23, 1996.
<br /> Based on the soil analytical data available for the site, Condor estimated that the volume of hydrocarbons
<br /> present in the soil beneath the site was approximately 13,000 pounds or 2,050-gallons(6.34 lbs/gal). Based
<br /> on the results of the SVE system evaluation and site background, Condor recommended that operation of
<br /> the ICU be suspended since the system did not appear to meet APCD permit conditions (i.e., 95%
<br /> destruction efficiency). Condor further recommended that a 150 SCFM catalytic oxidation unit (CAT-OX)
<br /> be installed at the site to extract and treat the gasoline contamination in the vadose zone. It was determined
<br /> that the configuration of the existing SVE wells appeared to be sufficient to remove a majority of the
<br /> remaining gasoline contaminants in the vadose zone.
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