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' Groundwater Investigation,Monitor Well Destruction and Installation,and Interim Remediation Pump Test Report Boyett Petroleum,419 S.Main St.,Manteca,CA January 30,2004 Page 10 below. This data was used to approximate the estimated lateral and vertical extent of MTBE isoconcentration contours in shallow and deep groundwater; in addition, this data represents the initial sampling event from monitoring wells MW-4R, MW-10, MW-11, and EW-1. Table 3 Laboratory Analytical Results for MTBE and Groundwater Elevation Data ' Novelmber 26, 2003 Screened Monitoring MTBE TOC Interval Depth to Groundwater ' Well -Sample 1.D. (99/L) Elevation' feet b s) Groundwater Elevation2 MW-13 NS NS 36.16 13-33 NM NM MW-25 NS NS 35.97 15-25 23.65 12.32 MW-3 3761-MW3-11-26-03 <M 36.18 15-25 22.44 13.74 MW-4R 3761-MW4R-11-26-03 11 35.21 10-25 23.07 12.14 MW-6° NS NS 36.07 10-25 DRY NM MW-75 Ni NS 36.42 10-25 23.53 12.89 _MW-8 6 NS NS 36.43 10-25 NM NM MW-9 3761-MW9-11-26-03 12 35.95 40-50 23.72 12.23 ' MW-10 3761-MW10-11-26-03 150 36.09 10-25 24.21 11.88 MW-1[ 3761-MWTI-1 1-26-03 1,000 36.15 29-39 23.98 12.17 EW-1 3761-EWI-11-26-03 230 36.23 29-39 24.11 12.12 `TOC Elevation:Elevations are referenced to NAD83 datum,NGS Benchmark HS 4486. 26roundwater Elevation:Elevations are measured from the top of the well casings and are referenced to the benchmark indicated above. 'Monitoring well MWA was destroyed on October 29,2003. • °Monitoring well MW-6 was dry. 5Monitoring wells MW-2 and MW-7 had insufficient water column to purge and sample. 6Monitoring well MW-8 was not sampled during the November 26,2003 monitoring event. Measurements: All measurements are in feet. NM =Not Measured Analytical: MTBE=methyl tertiary-butyl ether NS=Not Sampled Unit Conversions: pg/L:micrograms per liter=parts per billion(ppb) 4.0 MONITORING WELL DESTRUCTION AND INSTALLATION PROCEDURES This section includes a description of the site preparation, drilling procedures, monitoring well ' destruction, monitoring well installation, surveying, development, and sampling procedures, and the laboratory analytical methodology. 4.1 SITE PREPARATION Condor received well destruction and drilling permits from the SJCEHD for destruction of the on-site monitoring wells and installation of the proposed groundwater monitoring wells prior to initiating any fieldwork. The proposed monitoring well locations were marked with white paint and USA was notified 72 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. However, because the monitoring well locations were on private property, some utilities contacted ' by USA did not mark their lines past property boundaries and on to the site. Cruz Brothers conducted on- site underground utility line location and identificdtion services on October 17, 2003. The SJCEHD was notified of the fieldwork schedule 72 hours in advance. 1 �� CONDOR