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10 August 2004 AGE-NC Project No 96-0232 k Page 5of10 bottom of the well casing assembly to a point approximately two feet above the top of the screen, following filter pack placement, the uppermost well casing assembly was surged for approximately 20 minutes Approximately three feet of bentonite chips (annular seal) were placed above the filter a' `pack and were hydrated with clean tap water The remaining annular space was backfilled with - -- portland cement (grout seal) An as-built monitoring well-construction diagram is included as Figure 5 2 7 MONITORING WELL DEVELOPMENT On 20 May 2004, ground water monitoring well MW-19 (A and B) was developed utilizing (1) a 2-inch diameter, stainless steel hand bailer and (2) a Watera-Hydro-Lift H pump equipped with a mechanical arm and 3/8-inch diameter polyethylene hosing to surge and remove any remaining sediment accumulated at the bottom of each well Groundwater was bailed and/or hydro-lifted from each monitoring well until ground water was visually sediment free, approximately 20 gallons of water were removed from well MW-19A and 55 gallons of water removed from well MW-19B Monitoring well development water was transferred to the Flag City Chevron ground water . remediation system holding tank for treatment and disposal Following well development,ground water samples were collected from the purged wells MW-19A and MW-19B utilizing new,2-inch diameter disposable polyethylene bailers Groundwater samples were transferred into one-liter amber bottles without a preservative and into 40-m1 EPA-approved volatile organic analysis (VOA) vials containing 0 5 ml 18% hydrochloric acrd as a sample preservative Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground water sample containers were labeled with the well designation, date, - time, and sampler's initials Each preserved sample was logged on a chain-of-custody form, placed in a chilled container and transported to a DHS-certified laboratory for analysis for • TPH-g, TPH-d an TPH-mo by EPA Method 5030/8015M and LUFT/EPA Method 8015B, • BTEX by EPA Method 8020, and • 1,2-DCA, EDB, TBA, DIPE, ETBE, TAME and MTBE by EPA Method 8260B, 2 8 SURVEYING OF GROUND WATER MONITORING WELLS On 10 June 2004,a state of California state-licensed survey engineer from Baumbach&Piazza,Inc (BPI)surveyed/resurveyed reference points on the top of the well casings from wells MW-1 through Advanced GeoEnvi ron mental,Inc