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Site History
<br /> Canepa's Car Wash(Pacific Avenue)
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<br /> from 20 feet bgs to the capillary fringe. A summary of the soil and groundwater analytical data is contained
<br /> in Interim Status Report, Phase II Investigation, by WHF. Based on the initial data, the vertical and lateral
<br /> limits of contamination were not sufficiently defined. WHY proposed the installation of four (4) additional
<br /> monitor wells (MW-5 through MW-8) to fully characterize the groundwater plume. The PHS/EHD granted
<br /> approval of the additional investigation on January 19, 1994. Between March 9 and 11, 1994, WW
<br /> installed MW-5 through MW-8. TPH-G was detected in the soil sample collected from MW-6 at 50 and 55
<br /> feet bgs and from MW-7 at 50 feet bgs. TPH-G and BTEX were detected in groundwater samples collected
<br /> from MW-6, MW-7, and MW-8. A summary of the soil and groundwater analytical data is contained in
<br /> Phase II Site Characterization, by WHF. The wells were surveyed and groundwater elevation
<br /> measurements indicated that a groundwater mound existed beneath the site. This suggested that recharge or
<br /> leakage into the groundwater in the vicinity of MW I and MW-2 was occurring. Three potential sources of
<br /> recharge were identified: 1) the car wash water recycling pit system under the building, 2) a leaking or
<br /> broken sewer line that crosses the area, and 3) a leaking water supply line. An MBAS (Methyl Blue Active
<br /> Surfactants)test was conducted on groundwater samples collected at the site in July, 1994,to investigate the
<br /> 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
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<br /> I 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 126 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 (SW,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 the
<br /> ICU be suspended since the system did not appear to meet APCD permit conditions (i.e., 95% destruction
<br /> efficiency). Condor further recommended that a 150 SCFM catalytic oxidation unit (CAT-OX) be installed
<br /> at the site to extract and treat the gasoline contamination in the vadose zone. It was determined that the
<br /> configuration of the existing SVE wells appeared to be sufficient to remove a majority of the retraining
<br /> gasoline contaminants in the vadose zone.
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