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Thrifty Oil Co. Station #172
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<br /> (TPI -g) by EPA method 8015M modified for gasoline Ethanol and methanol were analyzed by
<br /> method D285 (Glycols-Alcohols)
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<br /> TPH-g, BTEX, and MTBE concentrations appear in Table 1, while historical oxygenate and alcohol
<br /> results are presented in Table 2 Copies of groundwater laboratory reports and chain-of-custody
<br /> documents are included in Appendix B The TPH-g, benzene, and MTBE isoconcentration maps
<br /> are presented as Figures 2,3, and 4, respectively The highest concentrations of TPH-g, benzene,
<br /> and MTBE in groundwater were found in monitoring well MW-11 (49,900 ug/L, 12,100 ug/L, and
<br /> 783 ug/L, respectively)
<br /> Since the third quarter of 1997, Thrifty has analyzed for the oxygenates di-isopropyl ether (DIPS),
<br /> ethyl-tert butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-butanol (TBA), and MTBE
<br /> by method 8260B, and alcohol's (ethanol and methanol) by ASTM standards D285 as requested by
<br /> the County of San Joaquin Public Health Services (CSJPHS) Laboratory results indicate no
<br /> alcohols or oxygenates were detected above the laboratory detection limit
<br /> Remediation Status
<br /> Vapor Extraction system
<br /> • On April 26, 2001, a new Baker Furnace Thermal Oxidizer Unit was placed into operation with the
<br /> hour meter reading at zero Presently, the remediation system is connected to soil vapor extraction
<br /> wells (VW-1, VW-2 (A,B), VW-3, VW-4 (A,B,C), VW-5 (A,B,C), and VW-6(A,B,C)) The only
<br /> wells operating throughout the quarter were VW-2A, VW-2B, VW-3, VW-5A, VW-5B, and VW-
<br /> 5C. During the third quarter of 2002, the soil vapor extraction unit(VEU) operated approximately
<br /> 1,957 hours for a total of 10,811 hours Approximately 5,761 pounds of hydrocarbons were removed
<br /> during the second quarter 2002 fora total of 36,162 pounds as of September 26, 2002 (Table 3)
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<br /> Influent and effluent vapor samples were collected on July 18, August 15, and September 12, 2002
<br /> In addition, vapor samples were collected on August 15, 2002 from selected well heads The well
<br /> head, influent, and effluent vapor samples were analyzed for TPH-g by EPA method 8015, and
<br /> BTEX/MTBE by EPA method 8021B A copy of the influent, effluent, and wellhead vapor sample
<br /> laboratory analytical results are presented in Appendix D
<br /> A historical summary of hydrocarbons removed by vapor extraction is presented in Table 3 The
<br /> Field Status Reports are included in Appendix C
<br /> Groundwater Treatment System
<br /> The groundwater treatment system was started in conjunction with the vapor treatment system on
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