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Mr Jim Barton May 16, 2006 ' Page 2 of 4 • • During the purge cycle, groundwater field parameter measurements consisting of specific conductance,pH, and temperature were measured using a groundwater water-quality meter • At least three times the volume of standing water was removed from the monitoring wells • After the purge cycle was complete, a groundwater sample was collected for analysis with a disposable polyethylene bailer and transferred to the appropriate laboratory-supplied sample container Pre-preserved laboratory-supplied containers were used for sample collection ' Groundwater monitoring and sampling field data sheets are presented as attachments to the G-R monitoring report,provided in Attachment 1 ' Subsequent to collection, samples were packed on ice, cooled to approximately 4°C, and shipped under appropriate chain-of-custody protocols for analysis to Lancaster Laboratories of Lancaster Pennsylvania, a California-certified analytical laboratory Analyses included the following parameters • total petroleum hydrocarbons (FPH) by United States Environmental Protection Agency (USEPA) Method 8015 Modified gas chromatography with a flame ionization detector (GC- FID), • benzene, toluene, ethylbenzene, and total xylenes(BTEX)by USEPA Method 8260B, ' • methyl t-butyl ether(MTBE)by USEPA Method 8260B, and • trichloroethene(TCE) and tetrachloroethene(PCE)by USEPA Method 8260B Quality assurance/quality control samples inclusive of trip blanks were also submitted for laboratory analysis A laboratory supplied trip blank accompanied each sample delivery group Trip blank samples were also collected for TPH, BTEX, and MTBE analyses Analytical results for the quarterly groundwater monitoring event are included as attachments to the G-R monitoring report, provided in Attachment 1 Purge water and equipment decontamination water generated during the sampling event was contamenzed for off-site disposal Monitoring Results Depth to water measurements were subtracted from the surveyed top-of-casing elevation to calculate the groundwater elevations for each monitoring well Depth to water and the calculated groundwater elevations are presented in Table 1 of the G-R monitoring report(Attachment 1) Calculated groundwater elevation data were then used to construct the groundwater potentiometric map provided as Figure 1 Groundwater elevations at the site ranged from 27 30 (MW-7) to 25 02 (MW-5) feet below mean sea level Groundwater elevations across the site have increased an average of 1 16 feet since the fourth quarter of 2005 The groundwater flow direction was generally to the east-southeast, as illustrated on the potentiometric map (Figure 1) and the horizontal hydraulic gradient ranged from approximately 0 01 to 11462822 doe BLASLAND, BOUCK& LEE, INC engineers scientists,economists