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1 ' , i ' S 02 March 2004 AGE-NC Project No 95-0144 Page 2 of 5 ' ;, On 29 October 2003, depth to water was measured In the fifteen ground water monitoring wells at the site On 30 October 2003,groundwater samples were collected from each wells MW-2,MW-4, MW-5, inadvertently from MW-21A/B, MW-20A/B and MW-25 In accordance with the revised ' monitoring schedule established at a 25 September 2002 meeting with the EHD ' 2 1 WELL MONITORING AND PURGING A Solznst water level meter was used to measure the depth to ground water In fifteen monitoring ' wells at the subject site relative to the tops of the well casings The ground water elevation, flow direction and hydraulic gradient were determined from these data(Table 1) ' After depth to water measurements were recorded, wells MW-2, MW-4, MW-5, MW-21A and MW-20A were purged using new,disposable plastic bailers,monitoring wells MW-21 B,MW-20B and MW-25 was purged using a Waterra Inertial pump equipped with ,5/8-Inch tubing and a ' foot-check valve Approximately three casing-water volumes of,water (approximately 6 25 to 18 ' gallons)were removed from the purged wells Wells MW-21B and MW-20A were balled dry,p'nor to removing three casing-water volumes Temperature, pH and conductivity of purged water were lie measured at regular purge-volume Intervals using an Oakton water analyzer The recorded field data and logs are Included In Appendix A All purged water was stored In 55-gallon DOT-approved ' drums on-site ' 2 2 COLLECTION OF GROUND WATER SAMPLES Water samples were collected from each purged monitoring well using new disposable bailers after ' allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume Samples were transferred Into 40-m1 EPA-approved volatile organic analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid as a sample preservative and Into 1-liter amber bottles without preservative ' The samples were labeled, stored on Ice and transported under chain-of-custody to McCampbell Analytical, Inc (MAI), a California Department of Health Services (DHS)-certified analytical laboratory Each sample was analyzed for • Total petroleum hydrocarbons quantified as gasoline(TPH-g),diesel(TPH-d)and motor oil' (TPH-mo) In accordance with EPA Methods 5030/8015 and 3550/8015, respectively, and ' • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether (MTBE) In accordance with EPA Method 8021B Advanced GcoEnvtronmental,Inc' r 1 '