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�(!0*kTC <br /> . ASS OCIATES INC <br /> LABORATORY ANALYSIS <br /> Groundwater samples from the monitoring wells were placed on ice and transported under chain- <br /> of-custody <br /> hain- <br /> ofcustody protocol to Sequoia Analytical laboratory Groundwater samples from wells MW1, <br /> MW2, MW3, and MW5 were analyzed for TPHg and TPHd by EPA method 8015 modified, and <br /> BTEX and methyl tertiary butyl ether (MTBE) by EPA method 8020 <br /> ANALYTICAL RESULTS <br /> The groundwater sample from well MWl contained benzene, ethylbenzene, TPHg, and TPHd at <br /> concentrations of 430 ppb, 8 9 ppb, 1,300 ppb, and 2,300 ppb, respectively The laboratory <br /> reported the chromatogram patterns indicated both gas and weathered diesel are present in well <br /> MW1 This is consistent with the previous analytical data collected from this well in September <br /> 1998 <br /> The groundwater sample collected from well MW2 contained benzene (160 ppb), ethylbenzene <br /> (21 ppb), TPHg (1,100 ppb), and TPHd (860 ppb) These detected concentrations represent an <br /> average decrease of approximately 63% compared to the previous analytical data collected from <br /> this well in December 1997 The laboratory reported the chromatogram patterns indicated both <br /> gas and weathered diesel are present in well MW2 Furthermore, MTBE was reported at a <br /> concentration of 88 ppb, however this detection was not confirmed by laboratory EPA method <br /> 8260 Previous groundwater samples were analyzed for fuel oxygenates utilizing EPA method <br /> 8260 and none were detected indicating the recent detection of MTBE is most likely a false <br /> positive due to chromatogram interference <br /> Only benzene (4 7 ppb), TPHg (130 ppb), and TPHd (180 ppb) was detected in the water sample <br /> collected from MW3 The laboratory reported the chromatogram patterns indicated both an <br /> unidentified hydrocarbon and gas are present in well MW3 The detection of these analytes is <br /> generally consistent with the most recent analysis of this well performed in June 1998, however <br /> the detected concentrations have increased by one order of magnitude since last sampled <br /> The groundwater sample from MW5 did not contain petroleum hydrocarbon constituents above <br /> laboratory method detection limits This is consistent with the previous analytical data collected <br /> from this well in June 1998 <br /> Analytical results for groundwater are summarized in Table 2 Laboratory data sheets and chain <br /> of custody documentation are included as Attachment 2 <br /> 625811QUARTLY14QR-1998 DOC 3 <br />