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ANALY'T'ICAL 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 <br /> Test 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 tert-butanol (TBA) following EPA Test Method 8260 Groundwater analytical results are <br /> summarized on Table 1 Laboratory reports and cham-of-custody documentation are presented in <br />' Appendix C <br /> Groundwater Analytical Results <br />' TPHg was detected in samples collected from wells MW-2, VW-1 and VW-2 at concentrations of <br /> 1,200, 110 and 8,900 gg/l respectively TPHd was detected in the groundwater samples collected <br /> from wells MW-2 and VW-2 at concentrations of 270 and 3,900 pg/l, respectively Benzene was <br /> detected in groundwater samples collected from wells MW-2 and VW-2 at concentrations of 170 and <br /> 2,400 pg/l, respectively Toluene, ethylbenzene and total xylenes were also detected in the samples <br /> collected from wells MW-2 and VW-2 at concentrations ranging from 18 pg/1 (toluene - VW-2) to <br />' 880 µg11 (total xylenes - VW-2) MTBE was detected in one sample, VW-2, at 47 gg/l TAME, <br /> 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 /> First Quarter - 2003 monitoring event are depicted on Figure 3, Petroleum Hydrocarbons in <br /> Groundwater-March 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, VW-1 and VW-2) <br /> Geocon recommends that the Central Valley Regional Water Quality Control Board (CVRWQCB) <br /> consider the Site for possible low risk closure and regulatory "no further action" status Pending <br />' evaluation by the CVRWQCB, the next quarterly monitoring event is scheduled for June 2003 <br /> 1 <br /> 1 <br /> Project No 58475-06-24D -3- April 28,2003 <br />