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15 December 2003 AGE-NC Project No 95-0173 Page 2 of 9 I at regular purge-volume Intervals using an Oakton water analyzer Field data and logs are included in Appendix A Purged ground water was containerized in 55-gallon drums and was stored on-site in an area lacking general public access Multi-level monitoring well MW-13 (A-C) and air sparge wells AW-1B and AW-2B were purged by lowering and raising a 3/8-Inch or %2-inch outer diameter, length-discrete polyethylene hose I equipped with a ball-valve water tip through the top chambers into the specific water-charged screened section,a Watera-Hydro-Lift 11 pump equipped with a mechanical arm was utilized to surge the polyethylene hose Approximately 3 to 4 gallons of ground water(a minimum of three casing- water volumes per well) were purged from each multi-level well chamber and approximately 13%Z and IS gallons were purged from air sparge wells AW 1-B and AW-2B, respectively Temperature, pH and conductivity were measured for stabilization at regular purge-volume intervals from each well using the Oakton water analyzer Field data and logs are in Appendix A Purged ground water from the above wells was transferred to 55-gallon drums and stored on-site in an area lacking general public access 2 2 GROUND WATER SAMPLING Following well purging,groundwater levels in the wells achieved a minimum of 80 percent recharge prior to sample collection Subsequently, ground water samples were collected from each purged well utilizing new,disposable polyethylene bailers and transferred into 40-ml EPA-approved vo I atile organic analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid as a sample preservative, ' ground water samples were collected from multi-level well MW-13 (A, B and C) and air sparge wells AW-1B and AW-2B and poured directly into the 40-m1 VOA vials utilizing the Watera hose bailer 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 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES After labeling,each ground water sample was logged on a chain-of-custody form,placed in a chilled container and transported to Castle Analytical Laboratory(CAL),a California Department of Health Services (DHS)-certified laboratory to be analyzed for • Total petroleum hydrocarbons quantified as gasoline (TPH-g)by EPA Method 5030/8015, • Benzene,toluene, ethylbenzene and xylene(BTEX)and methyl tertiary-butyl ether(MTBE) by EPA Method 8020, and ' Advanced GeoEnviron mental,Inc