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<br /> Revised Additional Vapor and Groundwater Monitoring Well Work Plan
<br /> Raymond Investment Corporation
<br /> October 30,2009
<br /> Page 2
<br /> investigation indicated that the soil and groundwaterlat the Site were impacted by TPH-G and TEPH-D at
<br /> some locations. Condor described the results of the investigation in the Soil and Groundwater
<br /> Investigation Report, dated June 1, 2004. In the report, Condor recommended preparing a work plan for
<br /> the installation of three groundwater monitoring wells and initiating quarterly groundwater monitoring at
<br /> the Site. In a letter dated July 7, 2004, SJCEHD directed the preparation and submittal of a work plan for
<br /> the installation of three groundwater monitoring wells at the Site. Condor prepared the Monitoring Well
<br /> Installation Work Plan, dated August 11, 2004, which was approved by SJCEHD in a letter dated August
<br /> 25, 2004.
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<br /> Condor installed three shallow groundwater monitoring wells (MW-1, MW-2, and MW-3) on September
<br /> 23 and 24, 2004. Condor prepared the Monitoring well Installation Preliminary Report and Monitoring
<br /> Well Destruction Work Plan, dated October 12, 2004, that described the installation of MW-3 and the
<br /> discovery of grout inside the well casing. Condor recommended that MW-3 be properly destroyed and a
<br /> replacement well (MW-3R) be installed approximately ten feet south of MW-3. In a letter dated October
<br /> 21, 2004, the SJCEHD approved the destruction ofIMW-3 and the installation of MW-3R. Monitoring
<br /> well MW-3 was properly destroyed and MW-3R installed on October 26, 2004. All field and analytical
<br /> activities involved in the installation, development, and sampling of monitoring wells MW-1,MW-2, and C
<br /> MW-3R and the destruction of monitoring well Mw-X are described in Condor's Monitoring Well f
<br /> Installation Report, dated December 15, 2004.
<br /> Quarterly groundwater monitoring was initiated after the wells were installed. Groundwater samples
<br /> were analyzed for TPH-G, TEPH-D, TEPH-MO, and total extractable petroleum hydrocarbons quantified
<br /> as kerosene (TEPH-K); benzene, toluene, ethyl) benzene, total xylenes (BTEX); and gasoline
<br /> oxygenates/additives. The gasoline oxygenates/additives included methanol, ethanol, tertiary-butanol
<br /> (TBA), methyl tertiary-butyl ether (MTBE), di-isopropyl ether (RIPE), ethyl tertiary-butyl ether(ETBE),
<br /> tertiary-amyl methyl ether(TAME), 1,2-dichloroethane(1,2-DCA), and ethylene dibromide(EDB).
<br /> Quarterly monitoring events began in the fourth f quarter 2004. The groundwater elevation in the M1
<br /> monitoring wells has ranged from approximately -13.5 to -21.0 feet above mean sea level (amsl) or 29.5
<br /> to 37.5 feet bgs. The general groundwater gradient for the Site has been approximately 0.005 ft/ft to the
<br /> 1 east-northeast, or 60 degrees east from true north.
<br /> Analytical constituents have rarely been detected at C or above the laboratory reported detection limits in the groundwater samples collected from monitoring wells MW-1, MW-2, and MW-3R. On May 4, 2005,
<br /> TPH-G and TEPH-D were detected in the groundwater sample collected from MW-1 at concentrations of
<br /> 170 micrograms per liter (µg/L) and 110 µg/L, respectively. On August 16, 2005, TPH-G and TEPH-D
<br /> were detected in MW-2 at 92 µg/L and 82 gg/L, respectively. No other analytical constituents were
<br /> detected at or above the laboratory reported detection limits in the samples collected from those wells on
<br /> those dates.
<br /> In her letter dated February 22, 2006, Ms. Victoria McCartney directed submission of a work plan
<br /> addressing the vertical and lateral extents of contamination at the Site. Ms. McCartney specifically
<br /> requested addressing the limits of contamination in the area where soil borings SB-3 and SB-4 were
<br /> advanced in May 2004, and recommended installation of two to three monitoring wells to assess the
<br /> lateral extent of groundwater contamination in that direction. Potential monitoring well locations were
<br /> limited due to a large building located approximately'20 to 30 feet from the area of SB-3 and SB-4 in the
<br /> down-gradient direction. Consequently, to assess the lateral extent of groundwater contamination,
<br /> j i� CONDOR
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