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� Y Texaco Trading &Transportation December 1996 (9647-0901) GROUND WATER MONITORING Ground Water Levels On October 22, 1996, Fugro collected depth to ground water measurements at the locations of ground water monitoring monitoring wells E, F, and REW-1 prior to purging and sampling. All depth to ground water measurements were conducted according to the Fugro standard operating procedures (SOP) included as Attachment 1. Field data sheets are included as Attachment 2. Ground water level data are summarized in Table 1. Since the last sampling event conducted in January 1989, the ground water elevation at all three monitoring well locations have increased an average of 1.05 feet. A ground water elevation hydrograph is included as Figure 3. On the basis of the October 22, 1996, measurements, ground water is estimated to flow to the north at an approximate hydrogeologic gradient of 0.004 feet per foot (ft/ft) (Figure 4 -Potentiometric Surface Map, October 22, 1996). Ground Water Sample Collection and Chemical Analyses On October 22, 1996, Fugro collected ground water samples at the locations of monitoring wells E, F, and REW-1. The ground water samples were collected according to the Fugro SOP included in Attachment 1, and were delivered under chain-of-custody documentation to Pace Analytical Services, Inc., a state-certified analytical laboratory. The samples were analyzed for concentrations of: • Total petroleum hydrocarbons identified as gasoline (TPH-g), benzene, toluene, ethylbenzene, and total xylenes (BTEX), and methyl-tertiary-butyl ether (MTBE) by California Department of Health Services LUFT method; • Total petroleum hydrocarbons identified as diesel fuel (TPH-d) by U.S. EPA method 8015 modified; • Total petroleum hydrocarbons identified as oil and grease (TPH-o) by U.S. EPA method 5520; and • Polynuclear aromatic hydrocarbon(PAI-)by U.S. EPA method 8310. 96470901.ART _ 7 _