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Canepa's Car Wash
<br /> 6230 Pacific Avenue,Stockton,CA
<br /> First Quarter Groundwater Monitoring Report,January 2004
<br /> Page 4 of b
<br /> sample collected from deep monitor well MW-12D contained TPH-G at concentrations of 0.054 mg/L.
<br /> No other contaminants of concern were detected at or above the laboratory reported detection limits in
<br /> MW-12D; this is consistent with the last two monitoring events. Monitor well MW-12D has generally
<br /> shown a decrease in contaminant concentrations each quarter since monitoring of the deep aquifer began
<br /> in October of 2001 (Table A, attached).
<br /> Laboratory analytical results indicate a decrease in BTEX, MTBE, and TPH-G concentrations detected in
<br /> monitor wells MW-1 and MW-2 compared to the November 2003 monitoring event, but remain
<br /> consistent with historic data. TAME and 1,2-DCA were detected in the sample collected from monitor
<br /> well MW-3 at concentrations of 1.6 and 130 gg/L, respectively. This is the third consecutive quarter that
<br /> these contaminants have been detected at MW-3. The concentration of MTBE detected in the
<br /> groundwater sample collected from monitor well MW-3 increased, consistent with an increasing trend for
<br /> that contaminant in that well (Figure 6, Attachment A). TBA, MTBE, BEX, and TPH-G were detected at
<br /> low concentrations in the sample collected from monitor well MW-11. Contaminant concentrations in the
<br /> sample collected from soil vapor extraction well SV-4 are generally consistent with historic results.
<br /> Benzene and MTBE iso-concentration contour maps are included as Figures 4 and 5 respectively;
<br /> Attachment A. Laboratory certificates of analyses and chain of custody record are included in Attachment
<br /> E.
<br /> Table 3
<br /> Groundwater Sample Laboratory Analytical Results (January 2004)
<br /> Constituent: Benzene Toluene Ethyl Total TPH-G MTBE Other Gasoline
<br /> Benzene Xylenes Ox enateslAdditives
<br /> MCL 1 µg/L 150µg/L 700 pg/L 1,750µg1L 13µg/L y�
<br /> • Analytical Method-* 8260E 8260E 8260B 8260B 8015m 8260B 8260E
<br /> Reporting Limits-> 0.5µg/L 0.5 pg/L 0.5µ&/L 1.0 ltg/L 0.05 0.5 0.5-200,000
<br /> Sample I.D. mgrL µg/l- pp/L
<br /> 1707-MW 1-01130/04 2,900 260 <50 329 3.8 440 < 10-<2,000
<br /> 1707-MW2-01130/04 10,000 560 1,800 2,100 41 <10 < 1.0-<20,000
<br /> < 1.0-<40
<br /> 1707-MW3-01/30/04 14 1.1 4.8 6.9 <0.05 1,800
<br /> 130(1,2-DCA); 1.6(TAME)
<br /> 1707-MW4-01/30/04 7.4 <0.5 <0.5 <1.0 0.064 <0.5 <0.5 -<20
<br /> 1707-M W9-01/30/04 <0.5 <0.5 <0.5 <1.0 <0.05 <0.5 <0.5-<20
<br /> 1707-MW 11-01130/04 4.1 <0.5 7.0 6.2 0.14 4.3 <0.5-<20
<br /> 13 TBA
<br /> 1707-M W 12D-01130/04 <0.5 <0.5 <0.5 <1,0 0.054 <0.5 <0.5 -<20
<br /> 1707-SVE4-01/30/04 90,000 79,000 4,700 21,700 380 350,000 < 10-<200,000
<br /> 00(TBA)
<br /> Bold analytical data exceed California MCL(Maximum Contaminant Level)
<br /> units: Anal, icak
<br /> mg/L=milligrams per liter=parts per million(ppm) B,T,E,X=benzene,toluene,ethyl benzene,total xylenes
<br /> µg/L=micrograms per liter=parts per billion(ppb) TPH-G=total petroleum hydrocarbons quantified as gasoline
<br /> Gasoline oxygenates/additives= methyl tertiary butyl ether(MTBE),ethanol,
<br /> tertiary butanol (TBA), di-isopropyl ether (DIPE), ethyl tertiary butyl ether
<br /> ($TBE), tertiary amyl methyl ether (TAME), 1,2-dichloroethane(1,2-DCA),
<br /> 1,2-dibromoethanc(1,2-EDB)
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<br /> �� CONDOR
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