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r y <br /> Analyses Labarata Anal <br /> ANALYTICAL METHODS AND RESULTS <br /> ry y <br /> Groundwater samples were delivered to Creek Environmental Laboratories, Inc , a Caltrans-approved <br /> and California-certified analytical laboratory, for the analyses of TPHg and TPHd following EPA Test <br /> Method 8015, BTEX following EPA Test Method 8020 and fuel oxygenate compounds (FOCs) <br /> including MTBE, tert-amyl methyl ether (TAME), ethyl tent-butyl ether (ETBE), di-isopropyl ether <br /> (DIPE) and tert-butanol (TBA) following EPA Test Method 8260 Groundwater analytical results are <br /> summarized on Table 1 Laboratory reports and chain-of-custody documentation are presented to <br /> Appendix C <br /> The laboratory is currently preparing electronic data files for submittal to Geotracker Geocon will <br /> upload the data and provide Caltrans with a Geotracker confirmation number as soon as the process is <br /> complete <br /> Groundwater Analytical Results <br /> TPHg was detected in samples collected from wells MW-2, VW-1 and VW-2 at concentrations of <br /> 12,000, 75 and 4,700 µg/l, respectively TPHd was detected in the groundwater samples collected from <br /> wells MW-2, MW-12 and VW-2 at concentrations of 11,000, 60 and 1,400 pg/l, respectively Benzene <br /> was detected in groundwater samples collected from wells MW-2 and VW-2 at concentrations of <br /> 1,500 and 1,300 pg/l, respectively Toluene, ethylbenzene and total xylenes were also detected in the <br /> samples collected from wells MW-2 and VW-2 at concentrations ranging from 17 µg/1 (toluene -VW- <br /> 2) to 2,600 pg/l (total xylenes -MW-2) MTBE was detected in one sample, VW-2, at 38 µg/l TAME, <br /> lie DIPE, TBA and ETBE were not detected above their respective laboratory method detection limits in <br /> each of the groundwater samples collected TPHg, TPHd, benzene, and MTBE concentrations for the <br /> Third Quarter - 2003 monitoring event are depicted on Figure 3, Petroleum Hydrocarbons to <br /> Groundwater- September 2003 <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> The highest concentrations of dissolved phase petroleum hydrocarbons appear to be limited to the <br /> immediate vicinity of the former UST excavation area (monitoring wells MW-2 and VW-2) Geocon <br /> recommends that the Central Valley Regional Water Quality Control Board (CVRWQCB) consider <br /> the Site for possible low risk closure and regulatory "no further action" status Pending evaluation by <br /> the CVRWQCB, the next quarterly monitoring event is scheduled for December 2003 <br /> Project No 58475-06-24H -3- October 24,2003 <br />