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r <br /> 10 . 0 ANALYTICAL RESULTS FOR GROUNDWATER <br /> The groundwater samples were analyzed by Kiff Analytical, ILC for TPH-G, <br /> BTEX, the fuel oxygenates MTBE, TBA, TAME, DIPE and ETBE, lead <br /> scavengers 1,2-DCA and 1,2-EDB, and the alcohols ethanol and methanol <br /> by EPA Method 8260. The analytical results are tabulated in Table Two. <br /> Copies of the certified analytical report and chain of custody form are <br /> included in Appendix G. <br /> Groundwater samples collected from monitoring well MW-1 contained 65 <br /> ppb MTBE. The groundwater samples collected from monitoring well <br /> MW-2 contained 10,000 ppb TPH-G, 310 ppb benzene, 440 ppb toluene, <br /> 170 ppb ethyl benzene, 1,100 ppb total xylenes, 1,400 ppb MTBE, 4.8 p p b <br /> tert-amyl methyl ether (TAME), and 82 ppb tert butanol (TBA). The <br /> groundwater samples collected from monitoring well MW-4 contained 260 <br /> ppb TPH-G, 17 ppb benzene, 5.0 ppb ethyl benzene, 7.5 ppb total xylenes, <br /> 140 ppb MTBE, and 6.0 ppb TAME. The groundwater samples collected <br /> from monitoring well MW-5 contained 2,600 ppb TPH-G, 11 ppb ethyl <br /> benzene, 1.6 ppb ethyl benzene, 84 ppb MTBE, and 52 ppb TBA. There <br /> were no compounds detected above laboratory reporting limits i n <br /> monitoring well MW-3- <br /> The benzene concentrations in groundwater samples collected from <br /> monitoring wells MW-2 and MW-4, and also the toluene concentration in <br /> groundwater samples collected from monitoring well MW-2, exceeded the <br /> DHS MCL for drinking water. The MTBE concentrations in groundwater <br /> samples collected from monitoring wells MW-1, MW-2, MW-4, and MW-5 <br /> exceeded the DHS MCL for drinking water. <br /> Isoconcentration maps for TPH-G, benzene, and MTBE are presented as <br /> Figures 7 through 9, respectively. <br /> 11 . 0 GROUNDWATER ELEVATIONS AND FLOW <br /> The ground surface elevation and top of casing elevation of each new <br /> groundwater monitoring well was surveyed relative to mean sea level <br /> (msl) by Farley Surveying, Inc. of Stockton, California on October 16, <br /> 2000. The northing and easting locations of the wells were surveyed <br /> relative to the California Coordinate System. The benchmark used for this <br /> survey was the City of Tracy GPS #21 located in the monument box at the <br /> centerline of Grant Line Road, near the east crosswalk of Tracy Boulevard. <br /> The survey information is presented in Appendix H. <br /> 574 West Grant Line Road Report — October 2000 <br /> -9- <br />