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1 <br /> 23y <br /> Jul 1998 <br /> ­AGE-NC Protect No 95-0144 <br /> ' Page 2 of 3 <br /> ' sample preservative and into 1-liter amber bottles without preservative The samples were <br /> transported in a chilled container, under chain-of-custody,to McCampbell Analytical, Inc (MAI) <br /> in Pacheco, California The samples were analyzed by <br /> ' • EPA Method 8015m for total petroleum hydrocarbons quantified as gasoline(TPH-g),diesel , <br /> (TPH-d), and motor oil (TPH-mo), and <br /> ' • EPA Method 602 for volatile aromatic compounds (benzene, toluene, ethylbenzene and <br /> xylenes, BTE&X) <br /> x <br /> 3.0. FINDINGS <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> The relative elevation of ground water in each well was calculated by subtracting the depth to water <br /> from the surveyed casing elevation(Table 1) Ground water elevation increased an average of 1 53 <br /> '•r feet between February and May 1998 The approximate hydraulic gradient for the current monitoring <br /> period was calculated to be 0 005 ft/ft with a northerly flow direction Ground water elevation <br /> contours derived from data collected on 07 May 1998 are depicted in Figure 3 Ground water was <br /> ' between five and eight feet above the screened interval in monitoring wells MW-1, MW-2, MW-4, <br /> MW-5 and MW-8 Ground water was approximately three feet above the screened interval in MW- <br /> 11, MW-12 and MW-13 <br /> 1 <br /> 3 2 ANALYTICAL RESULTS OF WATER SAMPLES <br /> During the May 1998 monitoring,TPH-g was detected in monitoring well MW-13 at a concentration <br /> of 120 parts per billion(ppb,reported as micrograms per liter),TPH-d was detected in wells MW-1, <br /> ' MW-2, MW-4 and MW-13 at concentrations ranging from 66 ppb to 170 ppb TPH-mo was not <br /> detected in samples collected during the May 1998 monitoring event <br /> Ethylbenzene and xylenes were detected in MW-1 at concentrations of 0 95 ppb and 0 60 ppb, <br /> respectively Benzene was detected in MW-13 at a concentration of 0 56 ppb BTE&X were not <br /> 1 detected in the remaining samples Analytical results of ground water samples are summarized on <br /> Table 2 The laboratory report (MAI Laboratory I D Nos 88978-88981) and chain-of-custody <br /> forms are included in Appendix B <br /> ' Advanced GeoEnvironmental,Inc <br /> i 1 , <br />