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CAMBRIA <br /> concentrations of 138,000 and 15,200 ppb, respectively Groundwater samples collected <br /> from shallow wells MW-2 through MW-6, MW-8, and RW-IA contained MTBE (by <br /> EPA Method 8260) at concentrations ranging from 2 52 to 205,000 ppb TAME was <br /> detected in wells MW-5, MW-8, and RW-IA at concentrations ranging from 154 to <br /> 5,100 ppb These data are shown on the chemical concentration map (Figure 2) and are <br /> summarized in the table in Blaine's monitoring report (Appendix A) Additional <br /> analytical data are summarized on Table I <br /> + Separate phase petroleum hydrocarbons were not present in well RW-lA this quarter <br /> • From March through June 1999, weekly groundwater extraction (GWE) was performed <br /> on well RW-IA Beginning in July 1999, GWE occurs bi-weekly During each GWE <br /> event, approximately 5,000 gallons of water is purged by a vacuum truck and transported <br /> to the Martinez Refining Company for recycling As of August 16, 1999, approximately <br /> 75,900 gallons of water have been removed from RW-IA These data are presented on <br /> Table 2 <br /> • Groundwater samples collected from deep monitoring wells MW-12 through MW-14 did <br /> not contain detectable concentrations of TPHg, benzene, MTBE, or other fuel <br /> oxygenates <br /> • Petroleum hydrocarbons and fuel oxygenates were not detected in the groundwater <br /> samples collected from the CalTrans irrigation well nor in any of the domestic wells <br /> The laboratory analytical results are summarized in the table in Blaine's monitoring <br /> report (Appendix A) <br /> Quarterly Sampling <br /> Groundwater samples from all wells were analyzed for total purgeable hydrocarbons as <br /> gasoline (TPHg) and methanol according to EPA Method 8015 (Modified), benzene, toluene, <br /> ethylbenzene, xylenes (BTEX), and methyl tertiary butyl ether (MTBE) according to EPA <br /> Method 8020 Groundwater samples from wells MW-2 through MW-6, MW-8, MW-12 <br /> through MW-14, RW-1A, the CalTrans well, and the domestic wells were also analyzed for <br /> fuel oxygenates (ethanol, TBA, MTBE, ETBE, DIPE, and TAME) by EPA Method 8260A <br /> Field monitoring data and chemical analytical data are presented in a summary table in <br /> Blaine's groundwater monitoring report (Appendix A) <br /> 241-0783 2 <br />