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Quarterly Monitoring Report,October 1998 Canepa s Car Wash(Pacific Avenue) November 17, 1998 Page -4 Laboratory analyses Indicated that the selected gasoline oxygenates/additives, excluding MTBE, were not detected, at or above the laboratory reported detection limits in any of the groundwater samples MTBE was detected in the groundwater samples collected from monitor wells MW-1 and MW-3 and soil vapor extraction well SV-7 at concentrations of 310, 8 6, and 1,800 �tg/1, respectively BTEX constituents were not detected at or above laboratory reported detection limits in the groundwater samples collected from monitor wells MW-3, MW-5, MW-7, and MW-8 BTEX constituents were detected in the groundwater samples collected from MW-1, MW-2, and SV-7 at concentrations ranging from 450 to 90 000 gg/l Toluene was detected in the groundwater samples collected from monitor wells MW-4 and MW-6 at concentrations of 3 4 and 0 4 pg/l, respectively TPH-G was detected in the groundwater samples collected from MW-1, MW-2, MW-4, and SV-7 at concentrations of 12, 120, 0 09, and 360 mg/1, respectively A summary of the laboratory analytical results is presented in Table 2, below, and in Figure 2, Appendix A Laboratory report sheets indicating analytical methods used, I detection limits, and the results of the analyses are Included in Appendix C Historical groundwater analyses are presented in Table A, Appendix B ' TABLE 2 LABORATORY ANALYSES (October, 1998) ' B T E X TPH-G MTBE Other Oxygenates* Detection limits 03 03 03 06 005 1 0 See Laboratory Monitor Well I D µg/1 gg/l µt, µg/l mg/1 µg/I Report Sheets 1707-MW1-10/23/98 4,300 620 450 1,000 12 310 ND 1707-MW2-10/23/98 37,000 4,900 1,400 5,600 120 ND ND 1707-MW3-10/23/98 ND ND ND ND ND 86 ND 1707-MW4-I0/22/98 ND 34 ND ND 009 ND ND 1707-MW5-10/22/98 ND ND ND ND ND ND ND ' 1707-MW6-10/22/98 ND 04 ND ND ND ND ND 1707-MW7-10/22/98 ND ND ND ND ND ND ND 1707-M 8-10/22/98 ND ND ND ND ND ND ND 1707-SV7-10/23/98 90,000 77,000 3,300 18,000 360 1,800 ND Unit Conversions Analytical null ngrte nrr billion fnnhl B T F X=hen7ene toluene ethyl bLn7ene ind xvient mg/l parts per million(ppm) I PH-G=total petroleum hydrocarbons,quantified as gasoline MTBE=Methyl tertiary Butyl Ether *Other Oxygenates/Additives=ethanol,Di-isopropyl ether,Ethyl tertiary- Butyl Ether,tertiary-amyl Methyl Ether and tertiary-Butanol ND=none detected at or above reported laboratory detection limit 5 0 DISCUSSION OF RESULTS The average depth to groundwater measured during the October groundwater monitoring event was approximately 35 7 feet below the monitor well measuring points The groundwater elevation ranged from 22 17 to 24 21 feet bmsl During the past four years, the depth to groundwater at the as I �� CONDOR