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S ECOR ARCO Service Station 595 May 6, 2004 Page 3 • Permitting and Access Agreements. The applicable permits for site assessment activities will be obtained from the SJCEHD prior to beginning work. Access agreements will be obtained for offsite drilling locations. • Replacement Groundwater Monitoring Wells. Replacement groundwater monitoring wells will be installed for well MW-2 and MW-4 at the approximate locations shown on Figure 2 using 8-inch diameter hollow-stem auger drilling equipment. No soil samples will be collected to a depth of 65 feet because of existing data. The borings will be continuously cored from 65 to 75 feet bsg to determine lithology at the bottom of the boring. Groundwater monitoring wells will be constructed of 2-inch diameter schedule 40 PVC pipe and will be screened ten feet above and ten feet below where groundwater is first encountered. Groundwater in wells is anticipated to be encountered at approximately 66 feet bgs. • Deep Groundwater Monitoring Wells. Four deep groundwater monitoring wells (DMW-4 to DMW-7), total depth of approximately 100 feet bgs, will be installed at locations shown on Figure 2 using 8-inch diameter hollow-stem auger drilling equipment. Soil samples will be collected at 5 foot intervals from ground surface to 90 feet bgs. The borings will be continuously cored from 90 to 100 feet bgs to determine lithology at the bottom of the boring. Groundwater monitoring wells will be constructed of 2-inch diameter schedule 40 PVC pipe and will be completed with 5 feet of 0.020 slotted screen. • Vertical Delineation Groundwater Monitoring Well. One groundwater monitoring wells (DMW-8), total depth of approximately 130-150 feet bgs, will be installed at locations shown on Figure 2 using 8-inch diameter hollow-stem auger drilling equipment. No soil samples will be collected from ground surface to 100 feet bgs because of existing soil data. The boring will be continuously cored from 100 to 150 feet bgs to determine lithology at the bottom of the boring. Based on lithology, a groundwater monitoring well will be constructed of 2-inch diameter schedule 40 PVC pipe and will be completed with 5 to 10 feet of 0.020 slotted screen. The depth of the screen interval will be determined in the field. • Soil Selection and Analysis. Selected soil samples will be sent under chain-of- custody procedures to a California state-certified laboratory. Soil showing positive readings on a PID or exhibiting field indications of impact will be analyzed for TPHg, benzene, toluene, ethylbenzene, total xylenes (collectively BTEX), and fuel oxygenates MtBE, EtBE, TBA, TAME, DIPE, 1,2-DCA, EDB ethanol by EPA Method 8260B. • Monitor Well Development, Sampling, and Analysis. Following installation, the newly installed monitoring wells will be developed by rigorously surging the well over the length of the screen interval and by purging approximately 10 casing volumes of water. Groundwater samples will be analyzed for TPHg, BTEX, and fuel oxygenates MtBE, EtBE, TBA, TAME, DIPE, 1,2-DCA, EDB, and ethanol by EPA Method 8260B. SECOR's field procedures for groundwater monitor well development and sampling are included in Attachment B. • Soil and Water Disposal. Soil cuttings generated during drilling operations will be stored on and wrapped in plastic sheeting or DOT-approved 55-gallon drums. Water