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• Site History
<br /> Canepa's Car Wash(Pacific Avenue)
<br /> Page 2 of 7
<br /> data is contained in Interim Status Report, Phase Il Investigation, by WHF. Based on the initial data, the
<br /> vertical and lateral limits of contamination were not sufficiently defined. WHF proposed the installation
<br /> of four (4) additional monitor wells (MW-5 through MW-8) to fully characterize the groundwater plume.
<br /> The PHS/EHD granted approval of the additional investigation on January 19, 1994. Between March 9
<br /> and 11, 1994, WHF installed MW-5 through MW-8. TPH-G was detected in the soil sample collected
<br /> from MW-6 at 50 and 55 feet bgs and from MW-7 at 50 feet bgs. TPH-G and BTEX were detected in
<br /> groundwater samples collected from MW-6, MW-7, and MW-8. A summary of the soil and groundwater
<br /> analytical data is contained in Phase II Site Characterization, by WHF. The wells were surveyed and
<br /> groundwater elevation measurements indicated that a groundwater mound existed beneath the site. This
<br /> suggested that recharge or leakage into the groundwater in the vicinity of MWA and MW-2 was
<br /> occurring. Three potential sources of recharge were identified. 1) the car wash water recycling pit system
<br /> under the building, 2) a leaking or broken sewer line that crosses the area, and 3) a leaking water supply
<br /> line. An MBAS (Methyl Blue Active Surfactants) test was conducted on groundwater samples collected
<br /> at the site in July 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.
<br /> MW-1 was used as a pumping well, and MW-4, MW-6, MW-7, and MW-8 were used as observation
<br /> wells. The results indicated an optimum pumping rate of 5 gpm with an effective radius of 140 feet.
<br /> Aquifer 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
<br /> since August 1996. Analyses of groundwater samples collected from selected SVE wells (SVE-1, 2, 3, 5,
<br /> 7, 8, and 9) indicated that high concentrations of TPH-G, BTEX, and MTBE were present in the former
<br /> location of the fuel dispenser islands. The groundwater table has risen approximately 18 feet since
<br /> quarterly monitoring of all eight site monitor wells 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
<br /> with Condor's proposal for SVE evaluation, dated April 8, 1996, and the addendum to the proposal, dated
<br /> May 2, 1996. The subsequent report was titled Soil Vapor Extraction (SVE) System Evaluation, dated
<br /> September 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). Due
<br /> to unknown variations in the lithology and contaminant concentrations, the actual volume of hydrocarbon
<br /> beneath the site may vary by an order of magnitude or more from the estimate.
<br /> Based on the results of the SVE system evaluation and site background, Condor recommended that
<br /> operation of the ICU be suspended since the system did not appear to meet APCD permit conditions (i.e.,
<br /> 95% destruction efficiency). Condor further recommended that a 150 SCFM catalytic oxidation unit
<br /> (CAT-OX) be installed at the site to extract and treat the gasoline contamination in the vadose zone. It
<br /> . was determined that the configuration of the existing SVE wells appeared to be sufficient to remove a
<br /> majority of the remaining gasoline contaminants in the vadose zone.
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