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Thrifty Oil Co. Station #172
<br /> Paget
<br /> monitoring wells MW-3 through MW-11, except MW-8 which was abandoned Groundwater
<br /> samples were obtained by EMC on August 16, 2001 and delivered in a chilled state, in an ice chest,
<br /> following strict Chain-of-Custody procedures to a state certified laboratory These samples were
<br /> analyzed for volatile aromatic compounds of benzene, toluene, ethylbenzene, and xylenes (BTEX)
<br /> and oxygenates (including MTBE)by EPA method 8260B,and total petroleum hydrocarbons(TPH-
<br /> g) by EPA method 8015M modified for gasoline Ethanol and methanol were analyzed by EPA
<br /> method D285 (Glycols-Alcohols)
<br /> TPH-g, BTEX, and MTBE concentrations appear in Table 1, while historical oxygenates and
<br /> alcohols results are presented in Table 2 Copies of groundwater laboratory reports and Chain-of-
<br /> Custody documents are included in Appendix B The TPH-g,benzene,and MTBE isoconcentration
<br /> maps are presented in Figures 2, 3, and 4. The highest concentrations of TPH-g, benzene, and
<br /> MTBE in groundwater were found in monitoring well MW-11 (151,000 ug/L, 6,880 ug/L, and 367
<br /> ug/L), respectively Monitoring well MW-6 indicated 9 6 ug/L MTBE Thrifty believes that this
<br /> data is erroneous since the past history of this well never presented MTBE at this level Also, well
<br /> MW-3 is between MW-6 and the on site MTBE contamination, and it was below the laboratory
<br /> detection limit for MTBE
<br /> Since the third quarter of 1997,Thrifty has analyzed for the requested oxygenates di-isopropyl ether
<br /> (DIPE), ethyl-tert butyl ethyl (ETBE),tert-amyl methyl ether (TAME), and tert-butanol (TBA), and
<br /> MTBE by method 8260B The following alcohols were also requested for analysis ethanol and
<br /> methanol Laboratory results indicate no alcohols or oxygenates (besides MTBE) were detected
<br /> Remediation Status
<br /> Vapor Extraction system
<br /> On April 12, 2001, a new Baker Furnace Thermal Oxidizer Unit was tested, and placed into
<br /> operation on April 26, 2001 with the hour meter reading at zero Presently, the remediation system
<br /> is connected to soil vapor extraction well (VW-1, VW-2 (A,B), VW-3, VW-4 (A,B,C), VW-5
<br /> (A,B,C), and VW-6(A,B,C)) During this quarter the only wells operating were VW-2A, VW-213,
<br /> VW-3,VW-4A,VW-4C,VW-5C,VW-6B,and VW-6C During this reporting period,the soil vapor
<br /> extraction unit (VEU) operated approximately 2,410 hours during the Third Quarter 2001
<br /> Approximately 2,083 pounds of total petroleum hydrocarbons as gasoline was removed during the
<br /> Third Quarter 2001 for a total of 27,143 pounds as of October 4, 2001 (Table 3) Zpp 8j)-mo
<br /> j
<br /> Effluent vapor samples were collected on July 16, August 8, and September 12, 2001 In addition,
<br /> samples were collected on July 16 and August 8, 2001 from selected well-heads, and from the
<br /> remediation system influent The well-head, influent, and effluent vapor samples were analyzed for
<br /> TPH-g by EPA method 8015, and BTEX/MTBE by EPA method 8021B A copy of the influent,
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