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446gical7-"Aus//W Page 8 <br /> ' Groundwater Monitonng Report <br /> Project No 425 2 <br /> January 31,2006 <br /> 3.0 FINDINGS AND DISCUSSION <br /> Groundwater analytical results and field observations are discussed below <br /> ' Zone A: <br /> • BTEX and TPH-G <br /> o MW-1, MW-4, MW-5 and MW-8 show the presence of low to moderate levels of <br /> BTEX and TPH-G constituents <br /> o MW-2 shows the presence of elevated concentrations of BTEX and TPH-G <br /> ' constituents <br /> o MW-3, MW-6 and MW-7 were non-detect above laboratory reporting limits for <br /> all analyzed constituents <br /> ' o Figure 8 shows contours of TPH-G concentrations in Zone A <br /> o Chart 1 shows the average TPH-g and Benzene historical variations in MW-1 <br /> • Benzene concentrations reached a peak in 2000 <br /> ' ■ TPH-G concentrations peaked in 2002 <br /> o Chart 2 shows the average TPH-g and Benzene historical variations in MW-2 <br /> ■ Benzene concentrations reached a peak in 1999 <br /> M ■ TPH-G concentrations peaked in 2001 <br /> o Chart 3 shows the average TPH-g and Benzene historical variations in MW-8 <br /> ■ Benzene concentrations peaked in 1998, 2001 and 2004 <br /> ' ■ TPH-G concentrations were relatively flat until 2004 <br /> ■ TPH-G concentrations are currently at there peak (2005) <br /> ■ MW-8 appears to be seeing the lateral spread of contamination from Former <br /> USTs Number 1 and 2 <br /> ■ If the current TPH-G peak seen in MW-8 is related to the TPH-G peak seen in <br /> MW-2 in 2001, it would suggest the contamination is moving approximately <br /> ' 20 feet per year <br /> ■ At this rate it is likely MW-7 will show benzene impact by early 2006 and <br /> TPH-G influence by summer of 2006 <br /> ' ■ At this rate it is likely MW-6 will show benzene impact by summer 2006 and <br /> TPH-G impact by early 2007 <br /> ' • Fuel Oxygenates <br /> o Trace levels of MtBE were detected in MW-1 and MW-5 <br /> o MW-2 may have MtBE present below the elevated laboratory reporting limits <br /> ' o All remaining monitoring wells were non-detect above laboratory reporting limits <br /> for all analyzed fuel oxygenate constituents <br /> • Lead Scavengers <br /> ' o MW-2, MW-4, MW-5 and MW-7 show the presence of 1,2-DCA <br /> o MW-1, MW-3, MW-6 and MW-8 were non-detect above laboratory reporting <br /> limits for 1,2-DCA <br />