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4.2 Groundwater Sampling Procedure - -) Prior to sampling, approximately three casing volumes of water were removed from each well using a disposable polyethylene bailer. During the removal of groundwater from the well, the following parameters were measured to ensure stable, representative samples : temperature, pH, conductivity and turbidity. The wells were sampled using disposable polyethylene bailers. Groundwater samples were ) collected in laboratory-supplied sample containers, sealed, labeled, and placed into ice chests containing ) a sufficient volume of ice to maintain a temperature of 4°C for transport to the off-site analytical laboratory. All samples were documented following standard chain-of-custody (COC) protocols. The samples were delivered to Severn Trent Laboratories, Incorporated, a California Department of Health Services certified analytical laboratory, in Pleasanton, California . Appendix B provides the laboratory reports and COC forms. The field data forms are found in Appendix C. S rvi 4.3 Chemical Analyses The Site history, past monitoring programs, and SJCEHD requests were examined to determine the analytical methods used during this monitoring event. 4.3.1 Gasoline and Fuel Oxygenates " 1 The groundwater samples from the monitoring wells were analyzed for gasoline and fuel oxygenates : Total petroleum hydrocarbons as gasoline (TPH-g), benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and tert-butyl alcohol (TBA) using EPA Method 826013. In addition the samples were analyzed for total petroleum hydrocarbons as kerosene (TPH-k) using EPA Method 8015M . � I 4.4 Groundwater Elevations and Flow 1 The most recent measurement of groundwater elevations, on 15 December 2004, produced an average gradient of 0. 001 and an approximate average groundwater flow direction of N 1080 E. This direction is similar to the previous interpretation by Ramage (Ramage, 2004) . However, the December 2004 gradient is much less than the previous gradient interpretation made by Ramage of 0.026 for measurements made on June 18, 2004 (Ramage, 2004). Table 3 presents measured groundwater elevations and Figure 3 presents a potentiometric surface map for the December 2004 monitoring event. ) 4 25971201 . DGD 6 February 2008 (J