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1!� concentrations ranging from 12 ppb (MW -3) to 93 ppb (DMW-1) Chemical concentrations were generally consistent with historical data except for increased concentrations of analytes in well SVE-1 Free product was not present at this site Groundwater elevations across the site increased by an average of 103 ft Groundwater flow was to the northeast at an approximate gradient of 0 002 ft/ft, which is generally consistent with historical data Interim remediation by groundwater batch extraction was performed at this site on March 18, April 19, April 29, and May 13, 2002 A total of 7,500 gallons were extracted from wells MW -1, MW -4, MW -6, SVE-1 and EW -1 during these extraction events Groundwater extraction data is presented in Tables 4 and 5 Groundwater elevation contour maps for before and after each event are presented as Figures 4 through 11 The contour maps from after extraction show a localized cone of depression around well EW -1 Groundwater batch extraction events have continued to be scheduled after May 13, and will be reported on in the third quarter 2002 monitoring report Field Data Sheets are included in Attachment B This report presents our understanding of existing conditions at the subject site The conclusions contained herein are based on the analytical results, and professional Judgment in accordance with current standards of professional practice, no other warranty is expressed or implied SECOR assumes no responsibility for exploratory borings or data reported by other consultants or contractors ATTACHMENTS: • Table 1 - Groundwater Elevation and Analytical Data • Table 2 - Fuel Oxygenates Analytical Data • Table 3 - Groundwater Gradient Data • Table 4 — Batch Extraction -Total Volume Removed from Wells MW -1, MW -4, MW -6, SVE-1, and EW - 1 • Table 5 — Batch Extraction Groundwater Elevation Data • Figure 1 - Groundwater Elevation Contour Map • Figure 2 - Groundwater Concentration Map • Figure 3 — MtBE Isoconcentration map • Figure 4 - Groundwater Elevation Contour Map -Before Batch Extraction March 18, 2002 • Figure 5 - Groundwater Elevation Contour Map -After Batch Extraction March 18, 2002 • Figure 6 - Groundwater Elevation Contour Map -Before Batch Extraction April 19, 2002 • Figure 7 - Groundwater Elevation Contour Map -After Batch Extraction April 19, 2002 • Figure 8 - Groundwater Elevation Contour Map -Before Batch Extraction April 29, 2002 • Figure 9 - Groundwater Elevation Contour Map -After Batch Extraction April 29, 2002 • Figure 10 - Groundwater Elevation Contour Map -Before Batch Extraction May 13, 2002 • Figure 1 i - Groundwater Elevation Contour Map -After Batch Extraction May 13, 2002 • Attachment A - Field and Laboratory Procedures • Attachment B - Certified Laboratory Analytical Reports, Cham -of -Custody Documentation, and Field Data Sheets cc Mr Marty Hartzell, Regional Water Quality Control Board - Central Valley Region (RWQCB-CVR) Ms Lori Duncan, SJCPHS t