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• Groundwater samples collected from monitoring well MW-6 this quarter <br /> contained 1,100 ppb toluene, 1,200 ppb ethyl benzene and 7,200 ppb <br /> total xylenes All of these concentrations exceeded DHS MCLs for <br /> drinking water No benzene or MTBE were detected in the groundwater <br /> samples collected from monitoring well MW-6 <br /> Groundwater samples collected from monitoring well MW-16, located <br /> near downgradient monitoring well MW-13 but screened in a deeper <br /> water-bearing zone 49 to 64-feet bgs, contained 26 ppb MTBE, 8 8 p p b <br /> TBA, 11 ppb ethanol and 58 ppb methanol Although this MTBE <br /> concentration exceeds the DHS MCL for drinking water, the concentration <br /> still represents a significant decrease in MTBE concentration with depth <br /> The mechanism for the movement of these compounds to this deeper <br /> zone is not known at this time None of the other groundwater samples <br /> collected from this depth contained concentrations of any compound <br /> exceeding DHS MCLs for drinking water <br /> Only trace concentrations of MTBE, below the DHS MCL for drinking water <br /> of 5 ppb, were detected in groundwater samples collected from <br /> monitoring wells MW-3, MW-4, MW-8, and MW-9 <br /> No TPH-G, TPH-D, BTEX, or oxygenates were detected in groundwater <br /> samples collected from monitoring wells MW-1, MW-2, MW-7, MW-10, <br /> MW-11, MW-12, MW-17, and MW-18 <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 /> 11 . 0 RECOMMENDATIONS <br /> 1 ) Further groundwater assessment is needed at the site to verify the <br /> remediation effectiveness at the site and to further define the extent <br /> of groundwater contamination downgradient of the site <br /> 2 ) If (a) the well construction of the impacted domestic wells show <br /> that these wells are conduits for groundwater to reach the deeper <br /> zone, and (b) analytical results for deeper borings in the well field <br /> show that only the shallow zone (above 20-feet) contains significant <br /> concentrations of MTBE, with no widespread impact to deeper <br /> Franks One Stop Report — November 2000 <br /> -1$- <br />