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ANA <br /> • LYYICAL METHODS AND RESULTS <br /> Laboratory Analyses <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 tert-butyl ether (ETBE), di-isopropyl ether <br /> (DIPE) and ter -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 in <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, MW-6, VW-1 and VW-2 at concentrations <br /> of 18,000, 65, 60 and 5,200 gg/l, respectively TPHd was detected in the groundwater samples <br /> collected from wells MW-2 and VW-2 at concentrations of 6,800 and 1,700 gg/l, respectively <br /> Benzene was detected in groundwater samples collected from wells MW-2 and VW-2 at <br /> concentrations of 2,700 and 1,500 gg/1, respectively Toluene, ethylbenzene and total xylenes were <br /> also detected in the samples collected from wells MW-2 and VW-2 at concentrations ranging from 7 9 <br />�. gg/1 (toluene - VW-2) to 4,000 gg/1 (total xylenes -MW-2) MTBE was detected in one sample, VW- <br /> 2, at 34 gg/l TAME, DIPE, TBA and ETBE were not detected above their respective laboratory <br /> method detection limits in each of the groundwater samples collected TPHg, TPHd, benzene, and <br /> MTBE concentrations for the Fourth Quarter - 2003 monitoring event are depicted on Figure 3, <br /> Petroleum Hydrocarbons in Groundwater -November 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 February 2004 <br /> I <br /> i <br /> Project No S8475-06-241 -3- December 29,2003 <br />