|
' and groundwater analytical data is contained in Interim Status Report, Phase 11 Investigation,by WW
<br /> . Based on the initial data, the vertical and lateral limits of contamination were not sufficiently defined
<br />'
<br /> WW- proposed the installation of four (4) additional monitor wells (MW-5 through MW-8) to fully
<br /> characterize the groundwater plume The PHS/EHD granted approval of the additional investigation on
<br /> January 19, 1994 Between March 9 and 11, 1994, WJ-W� installed MW-5 through MW-8 Moderate
<br />' concentrations of gasoline were detected in the soil from MW-6 at 50 and 55 feet bgs and from MW-7 at 50
<br /> feet bgs Low to elevated concentrations of TPH-G and BTEX were detected in groundwater samples
<br /> collected from MW-6, MW-7, and MW-8 A summary of the soil and groundwater analytical data is
<br />' contained in Phase II Site Characterization, by WHF The wells were surveyed and gradient calculations
<br /> indicated that a groundwater mound existed beneath the site indicating that recharge or leakage into the
<br /> groundwater in the vicinity of MW-1 and MW-2 was occurring Three potential souicas of lucharge were
<br />' identified 1) the car wash water recycling pit system under the building, 2) a leaking or broken Sewer line
<br /> that crosses the area, and 3) a leaking water supply line An MBAS (Methyl Blue Active Surfactants) test
<br /> was conducted on groundwater samples collected at the site in July, 1994, to investigate the presence of
<br /> 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 wells
<br /> The 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, 1995
<br /> Historical groundwater analytical data indicated elevated concentrations of TPH-G and BTEX in MW-1,
<br /> MW-2, MW-6, and MW-7 Low to trace concentrations of TPI-1-6 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 Analysis of groundwater samples collected from selected SVE wells (SVE-1, 2, 3, 5, 7, 8,
<br /> and 9) indicate that high concentrations of TPH-G, BTEX, and MTBE are present in the former location of
<br />' the fuel dispenser islands The groundwater table has risen approximately 15 feet since quarterly
<br /> monitoring of all eight site monitor wells began in March I994
<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 Api 11 8, 1996, and the addendum to the proposal, dated May 2,
<br /> 1996 The report was titled Soil Vapor Extraction (SVE)System Evaluation,and dated September 23, 1996
<br /> Condor calculated that, based on the soil analytical data available for the site, the volume of hydrocarbons
<br /> present in the soil beneath the site is estimated at approximately 13,000 pounds or 2,050-gallons (6 34
<br /> lbs/gal) Due to unknown variations in the lithology and contaminant concentrations, the actual volume of
<br /> hydrocarbon 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 /> I 95%destruction efficiency) Condor further recommended that a 150 SCFM catalytic oxidation unit(CAT-
<br /> OX) be installed at the site to extract and treat the gasoline contamination in the vadose zone It was
<br /> determined that the configuration of the existing SVE wells appeared to be sufficient to remove a majority
<br /> of the remaining gasoline contaminants in the vadose zone
<br /> 2
<br /> I
<br />
|