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t03 February 2006 • AGE-NC Project No 98-0533 Page 2 of 4 the wells to achieve a minimum 80% recovery of the pre-purge water volume The samples were transferred into laboratory-supplied 40-m1 EPA-approved volatile organic analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid as a sample preservative The sample vials were then labeled with the monitoring well designation,date, time of sampling and the sampler's initials The samples were transported in a chilled container under chain of custody to Cal Tech Environmental Laboratories (CTEL) for analysis The samples were analyzed for • Total petroleum hydrocarbons quantified as aviation gasoline (TPH-ag) in accordance with EPA Method 5030/8015M, • Benzene,toluene,ethylbenzene and xylene(BTEX)and methyl tertiary-butyl ether (MTBE) in accordance with EPA Method 80-21Y �J ice. • Fuel oxygenates - tertiary butanol (TBA), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and MTBE in accordance with EPA Method 8260B, and • Ethylene dibromide (EDB) and 1,2 dichloroethane (1,2 DCA) in accordance with EPA method 8260 • At the request of the EHD,a ground water sample from the on-site domestic well was also collected and analyzed To ensure that formation water was being produced, water was allowed to run out of the well for approximately 20 minutes,which was long enough to automatically turn the well pump on Ground water was poured directly into the 40-m1 VOA vials from a valve at the well head 3.0. FINDINGS 1 Ground water eley4tion, ground water gradient and flow direction were determined from field data, ground water vi-ere assessed by laboratory analysis of ground water samples 3 1 GROUND WATER GRADIENT AND tOW DIRECTION ' The elevation of ground water in each of thethree monitoring wells was calculated by subtracting the depth to ground water from the su eyed relative casing elevations (Table 1) Depths to ground water ranged from 80 71 feet to 81 feet bsg for an average of 80 96 feet bsg Depth to ground ' water increased an average o 0 3 feet since the previous monitcglng event in September 2005 Ground water elevations at the site ranged from 23 96 feet (MWto 24 10 feet (MW-3) below ' mean sea level The ground water gradient was calculated to be 0 001 ft/ft directed towards the • northeast Figure 3 illustrates the contoured ground water elevations as measured on 02 December 2005 1 Advanced GeoEnvironmental,Inc 1 '