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. FIGURE 6B <br /> Figure 613 represents the benzene groundwater plume in the B zone The Sanchez plume <br /> is elongated extending west of MW2 out towards "Geoprobe" hole P9 Again the highest <br /> concentrations are associated with the area that was over-excavated contained temporary <br /> piezometers PZ1B and PZ213 with 1,800 ug/L and 32 ug/L Benzene respectively on <br /> January 31, 2003 Newly installed excavation monitor well MW10 contains 520 ug/L <br /> and downgradient well MW613 contains 3 7 ug/L <br /> MTBE <br /> FIGURE 7A <br /> Figure 7A represents the MtBE groundwater in the A zone along with the plume beneath <br /> CCFF The Sanchez plume is elongated extending west of the over-excavated area <br /> (MW 10) out to "Geoprobe" hole P9 were degradation has left only minor TPHg (470 <br /> ug/L), Toluene (0 65 ug/L) and tert-Butanol (11 ug/L), the degradation byproduct of <br /> MTBE Highest concentrations of MtBE are associated with the areas north and west of <br /> CCFF well MWi which currently contains 27 ug/L The excavated area (MWIO) <br /> formerly contained temporary piezometers PZ1A and PZ2A (highest concentration of <br /> MtBE 420 ug/L and 72 ug/L respectively on January 31, 2003) The MW10 area has <br /> since reduced to 6 3 ug/L Newly installed downgradient well MW9A is below <br /> laboratory lower detection limits <br /> The CCFF MtBE plume is associated with well MWI and shows a connection to the <br /> Sanchez plume Pumping from well MW10 is most likely pulling the MtBE plume from <br /> CCFF onto the Sanchez property, thus removing MtBE from both sites while pumping is <br /> occurring <br /> FIGURE 7B <br /> Figure 7B represents the MtBE plume in the B zone Figure 7B resembles figure 7A with <br /> the only difference being an increase in MtBE found at well 813 Historic water samples <br /> obtained from piezometers PZ1B and PZ213 contained 78 and 21 ug/L respectively <br /> TBA <br /> FIGURE 8A <br /> Figure 8A represents the TBA plume in the A zone TBA is only evident in well MW8A <br /> at 6 9 ug/L Historically TBA was detected in "GeoProbe" holes P8 and P10 at 11 and 6 <br /> ug/L respectively (February 200 1) <br /> • <br /> 10 Sanchez QM ')" 2005 <br />