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it �f li CAME RIA I to the SVE test,MTBE was delineated to the southwest, south,east, and northeast of the northwestern dispenser by bonngs SB-1,SB-3, SB-4, SB-5, and SB-9 After the SVE test, a confirmation boring (VE-3)was placed in the source area,adjacent to the boring with the highest MTBE detections(SB-2) No MTBE was detected in the confirmation boring The 15 5 fbg sample collected from VE-3 contained 1 1 ppm tertiary butanol(TBA) TBA was not detected in deeper soil from this boring and has not been detected elsewhere onsite The soil analytical data collected from this confirmation boring indicate that the SVE test was successful in removing a significant amount of the residual source material from the soil beneath the northwestern dispenser and suggest there is little or no remaining source material Therefore, it is unlikely that any remaining mass would impact groundwater beneath the site TPHg, BTEX, and fuel oxygenates are delineated vertically in soil above 84 fbg by boring CPT-2 Soil tables and sample locations are presented in Attachment B Hydrocarbon Distribution to Groundwater. There are currently two groundwater monitoring wells onsite(MW-5 and MW-8)and one offsite well in the bicycle lane of West Kettleman Lane(MW-6) During the third quarter 2002 sampling event, no TPHg, BTEX, or MTBE were detected in groundwater from any of the wells No MTBE has been detected in well MW-5,the source area well, since September 2000 (with the exception of a 1 1 ppb detection in November 2001), and TPHg and • benzene have never been detected in this well Note that the November 2001 results for all three wells are not consistent with historical or current concentrations, and are considered anomalous Groundwater samples from well MW-6 have contained the highest historical MTBE concentrations (99 ppb in December 2001) The groundwater flow direction beneath the site has consistently been towards the south to southwest Therefore, MW-6 is the upgradient well, and it is unlikely that the MTBE detected in this well originated from the subject site MTBE has not been detected in this well since January 2002 Samples from well MW-8 have contained sporadic,low-level MTBE detections (0 54 to 22 ppb) The most recent detection (4 0 ppb) occurred in March 2002 As there have not been corresponding MTBE detections in well MW-5,the source area well,these detections may also be attributed to an offsite source Historical groundwater data and the third quarter 2002 groundwater contour map are included in Attachment C i I 1346 4