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104 82 feet bgs, 0 08 feet higher than the groundwater measured during the fourth quarter 2003
<br /> monitoring event These data are similar to groundwater data from previous quarters Depth-to-water
<br /> measurements were corrected to mean sea level (MSL) and used to construct a groundwater elevation
<br /> contour map (Figure 3) Wells that contained less than 1 foot of water are Interpreted to be dry and are
<br /> Indicated as "dry" on Figure 3 Groundwater flow on March 15, 2004, was to the southwest at a gradient
<br /> of 0 108 ftlft
<br /> During the first quarter 2004 sampling event, GRO, benzene, and MTBE were reported In the samples
<br /> collected from wells VW-2, VW-3, and VW-6 GRO was also reported In well VW-5 The highest
<br /> concentrations of GRO (24,000 pg/L), and MTBE (180 pg/L) were reported In well VW-3 The highest
<br /> concentration of benzene (4,800 µg/L) was reported in well VW-6 1,2-DCA (16 µg/L) was reported In well
<br /> VW-2 TBA, TAME, DIPE, ETBE, EDB, or ethanol were not reported in any of the wells Wells VW-4 and
<br /> MW-3 purged dry and did not recover, therefore samples could not be collected from these wells
<br /> Petroleum hydrocarbons or fuel oxygenates were not reported In the domestic well These data are
<br /> similar to chemical analytical data from previous quarters GRO, benzene, and MTBE analytical data for
<br /> the samples collected on March 15, 2004, are presented In Figure 4 Analytical data were submitted to
<br /> the State Water Resources Control Board as required by AB2886 The electronic delivery receipt is
<br /> attached In Appendix C
<br /> Borings B-39 and B-40 were advanced to approximately 150 feet bgs under the direction of a Stratus
<br /> geologist Geologic logs and soil analytical data for these boreholes will be Included in a site assessment
<br /> report
<br /> SVE System Operation and Maintenance
<br /> Stratus conducted four site visits during the first quarter 2004 to conduct systems start-up, operation and
<br /> maintenance of the SVE system, and to collect compliance samples The SVE systems start-up was
<br /> initiated on March 9, 2004 In the presence of SJVAPCD The SVE systems were shutdown on March 9,
<br /> 2004, after collecting the compliance air samples, pending evaluation of destruction efficiencies and mass
<br /> emission rates for both the SVE systems Upon receipt of analytical results and complying with SVPACD
<br /> ATC requirements, the remediation systems were started for continuous operation beginning March 15,
<br /> 2004 SVE unit 2 (SL No 9230) was observed non-operational on March 23, 2004 and March 29, 2004
<br /> due to high temperature alarm The SVE unit 2 was re-started on March 23, 2004 and March 29, 2004, by
<br /> adjusting the temperature controls
<br /> During the first quarter 2004, the influent GRO concentrations to SVE unit 1 and SVE unit 2 were at 2,800
<br /> mg/m and 2,500 mg/m3, respectively The average soil vapor extraction flow rates for SVE unit 1 and
<br /> SVE unit 2 were observed at 157 30 cubic feet per minute (cfm) at an average applied vacuum of 11
<br /> inches of water column, and 226 15 cfm at an average applied vacuum of 12 Inches of water column
<br /> Based on the analytical results of air samples collected on March 9, 2004, approximately 42 42 lbs of
<br /> GRO has been removed from the subsurface using SVE unit 1 and approximately 44 50 lbs using SVE
<br /> unit 2 The GRO, benzene, and MTBE mass emission rates for SVE unit 1 were estimated to be
<br /> approximately 0 42 lbs/day, 0 005 lbs/day, and 0 006 lbs/day, respectively, while that for SVE unit 2 were
<br /> estimated to be less than 0 18 lbs/day, 0 002 lbs/day, and 0 002 lbs/day, respectively The destruction
<br /> efficiency of both the SVE systems for GRO was observed to be greater than 99% The SVE system Is
<br /> operating as designed and Is in compliance with the SJVAPCD permit requirements
<br /> i
<br /> P 1Bp-Arco for URS161001Quarterly120041Arco 6I00_IQ04 doc 57RA7U5
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