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1 <br /> Geological reelr a Inc Page 8 <br />' Groundwater Monitoring Report <br /> Project No 425 2 <br /> Apnl 27,2006 <br />' As required under AB2886, the laboratory data were submitted electronically to GeoTracker <br /> on April 26, 2006 and the confirmation number is 1516478121 <br /> 3.0 FINDINGS AND DISCUSSION <br /> Groundwater analytical results and field observations are discussed below <br /> oun yt <br /> Zone A: <br /> • BTEX and TPH-G <br /> o 1\4W-1, MW-4, MW-5 and MW-8 show the presence of low levels of BTEX and <br />' 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 /> ■ TPH-G concentrations peaked in 2001 <br /> ■ Both constituents show a marked increase during this quarter <br /> C) <br /> 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 were at their peak in 2005 <br /> ■ Both constituents show decreasing trends this quarter <br /> ■ MW-8 appears to be seeing the lateral spread of contamination from Former <br /> USTs Number 1 and 2 <br /> ' 0 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 /> • 1,2-DCA concentrations have gradually increased in MW-7 over the last <br /> ' twelve months,further suggesting the plume is migrating toward this well <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 /> 1'10 o MW-2 may have MtBE present below the elevated laboratory reporting limits <br /> 1 <br />