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collected from monitoring well MW-16, located near downgradient <br /> monitoring well MW-13 but screened in a deeper water-bearing zone 49 <br /> to 64-feet bgs, contained 26 ppb MTBE, 8 8 ppb TBA, 11 ppb ethanol a n d <br /> 58 ppb methanol Although this MTBE concentration exceeds the DHS <br /> MCL for drinking water, the concentration still represents a significant <br /> decrease in MTBE concentration with depth <br /> Groundwater samples collected from monitoring well MW-6, ,lust south of <br /> the gasoline USTs, contained 1,100 ppb toluene, 1,200 ppb ethyl benzene <br /> and 7,200 ppb total xylenes <br /> Groundwater samples collected from all other portions of the property, <br /> including monitoring wells MW-1, MW-2, MW-3, MW-4, MW-7, MW-8, <br /> MW-9, MW-10, MW-11, MW-12, MW-17, and MW-18 contained either <br /> non-detectable hydrocarbon concentrations or concentrations below DHS <br /> MCLs or drinking water <br /> The only HVOC concentrations detected at the site were relatively low <br /> concentrations of PCE in the groundwater sample collected from <br /> monitoring well MW-1, and relatively low concentrations of 1 ,2- <br /> • dichloropropane in groundwater samples collected from several wells <br /> screened in water-bearing zones below 19-feet bgs None of these HVOC <br /> concentrations detected exceeded DHS MCLs for drinking water <br /> 2. 17 November 2000 Monitoring Well Resamnlinz <br /> In November 2000, ASE resampled the monitoring wells on the north <br /> shoulder of West Yosemite Avenue to confirm the presence of MTBE in the <br /> intermediate zone and to provide additional baseline data for the <br /> evaluation of the interim remediation system Groundwater samples <br /> collected from monitoring well MW-16, screened in the intermediate <br /> water-bearing zone 49 to 64-feet bgs, contained 29 ppb MTBE These <br /> results are slightly lower than results in the September sampling The <br /> highest hydrocarbon concentrations were once again detected in <br /> groundwater samples collected from monitoring well MW-13, which <br /> contained 14,000 ppb TPH-G, 1,500 ppb benzene, 77 ppb toluene, 1 ,300 <br /> ppb ethyl benzene, 390 ppb total xylenes, 2,400 ppb MTBE, 9 5 ppb TAME, <br /> and 770 ppb TBA These results are slightly higher than those during the <br /> previous sampling Analytical results for this sampling are presented in <br /> Appendix B <br /> Frank's One Stop Workplan — December 2000 <br /> -8- <br />