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1 Fourth quarter 2004 Groundwater Monitonng Report
<br /> Eckert Cold Storage,Manteca,California
<br /> February 8,2005
<br /> Page 3
<br /> . generally consistent with historic laboratory analytical results for those two monitoring wells The
<br /> laboratory analytical results of the groundwater sample collected from MW-5, however, indicate higher
<br /> ' concentrations of benzene and TPH-G than in historic results for that well Conversely, the laboratory
<br /> analytical results of the groundwater sample collected from MW-8 indicate gasoline constituents at lower
<br /> concentrations than in historic results for that well
<br /> Upon initial review of the MW-5 and MW-8 data, it appeared that the samples may have been switched
<br /> and mislabeled in the field or at the laboratory because the current data would have been consistent with
<br /> ' historic results if that had occurred MW-5 and MW-8 were re-sampled, therefore, on January 10, 2005
<br /> The data from the re-sampling, however, indicated that there was no field or laboratory mistake and that
<br /> the groundwater contaminant conditions in the location of the wells had changed The current laboratory
<br /> analytical results, including the verification sampling conducted on January 10, 2005, are shown in Table
<br /> ' 2, below Historic groundwater monitoring data are included in Attachment C Laboratory certificates of
<br /> analyses and the chain-of-custody documentation for the samples are included in Attachment D The
<br /> samples were analyzed by Argon Laboratories of Ceres, California
<br /> ' Table 2—Groundwater Sample Laboratory Analytical Results
<br /> (December 30, 2004 and January 10,2005)
<br /> ' GASOLINE OXYGENATES/ADDITIVES
<br /> B T E X TPS-G
<br /> MTBE Other Gasoline Oxygenates/Additives
<br /> tUnits pg/L pg/L µg/L µg/l, mg/L µg/L µg/L
<br /> ' Analytical Method 8260B 8260B 8260B 8260B 8015M 8260B 8260B
<br /> Sample 10
<br /> 3471E-MW4-12/30/04 105 105 105 1 110 <0 05 11 14(1,2-DCA),0
<br /> ' 347 1 E-MW5-12/3 0/04 2,000 3 9 39J. 12 3 8 18 160(TBA),
<br /> 3471E-MW7-12130/04 105 105 105 <10 <0 05 <05 <05—5 0
<br /> t3471 E-MW8-12130/04 1 6 10 5 1 1 <i 0 <0 05 19 4 9(DiPE),4 2(1,2-DCA),
<br /> 3471 E-MWS-01/10/05 580 <10d <101 <20d 14 13 <10—<1001
<br /> ' 3471 E-MW8-01/10105 20 <0 5 <0 5 20 008 44 15(TBA),4 9(1,2-DCA),
<br /> Units _Analytical
<br /> mg/L milligrams per liter,parts per million(ppm) B,T,E,X=benzene,toluene,ethyl benzene,total xylenes
<br /> ' pg/L micrograms per liter parts per billion(ppb) TPH-G=total petroleum hydrocarbons quantified as gasoline
<br /> Gasoline oxygenates/additives= methyl tertiary butyl ether(MTBE),ethanol,
<br /> tertiary-butanol (TBA), di-isopropyl ether(DIPS), ethyl tertiary butyl ether
<br /> (ETRE),tertiary amyl methyl ether(TAME), 1,2-dibromoethane (EDB), 1,2-
<br /> ' dichloroethane(1 2-DCA)
<br /> �=all other oxygenates/additives were not detected at or above the laboratory
<br /> reported detection limits
<br /> d= Sample diluted due to high concentration of target analytes and/or
<br /> ' high organic content
<br /> FUTURE WORKIRECOMMENDATIONS
<br /> ' The SJCEHD has indicated that continued quarterly groundwater monitoring is required at the site The
<br /> next quarterly monitoring event is scheduled for March 2005 In correspondence dated March 21, 2003,
<br /> . Mr Harlin Knoll of SJCEHD approved Condor's request to reduce the sampling frequency of MW-5
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<br /> �1� CONDOR
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