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Canepa s Car Wash
<br /> 6230 Pacific Avenue,Stockton,CA
<br /> Thsrd Quarter Groundwater Monitoring Report,July 2005
<br /> Page 4 of 8
<br /> • Current groundwater sample laboratory analytical results Indicate that constituent concentrations in
<br /> monitoring wells MW-2, MW-4 through MW-7, MW-9, MW-10, and MW-12D are consistent with
<br /> historic values with none of the constituents of concern detected at or above laboratory reported detection
<br /> limits in all but MW-2 Since monitoring well MW-1 was designated the primary pumping well for the
<br /> on-site treatment system in October 2004, contaminant concentrations have remained at historic highs
<br /> (with the exception of concentrations detected from the December 8, 1994 and June 12, 1995
<br /> groundwater samples) Constituent concentrations in MW-3 are consistent with histone values with the
<br /> exception of MTBE, which has been increasing since January 21, 2005 Contaminant concentrations have
<br /> returned to historic levels in MW-11 with the exception of xylenes, MTBE, and TPH-G, which have
<br /> remained elevated since the January 21, 2005 sampling events
<br /> Benzene and MTBE iso-concentration contour maps are included as Figures 4 and 5, respectively,
<br /> Attachment A Historic laboratory analytical results from groundwater samples collected from MW-3
<br /> indicate a trend of increasing MTBE concentrations since April 11, 2001 (Figure 6, Attachment A)
<br /> Groundwater sample laboratory analytical results for the current monitoring event are provided in Table
<br /> 3, below Laboratory certificates of analyses and chain of custody records are included in Attachment F
<br /> Table 3
<br /> Groundwater Sample Laboratory Analytical Results (July 28, 2005)
<br /> Constituent Benzene Toluene Ethyl Total TPH-G MTBE
<br /> Other Gasoline
<br /> Benzene Xylenes Oxygenates/Additives
<br /> MCL l pg/L 150 pg/L 700 pg/L 1,750 pg/L 13 pg/L
<br /> Analytical Methods 8260B 8260B 8260B 8260B 8015m 8260B 82608
<br /> . Reporting Limits-+ 0 5 pg/L 0 5 pg/L 0 5 pg/L 1 0 pg/L 005 05 05-20
<br /> Sample I D mg/L pg/L pg/L
<br /> MW-1 8,180 4,480 241 3,730 243 12,300 < 1 0-<40
<br /> MW-2 9,660 652 2,060 4,392 346 <1 0 < 1 0-<40
<br /> MW-3 <1 0 <1 0 <1 0 <2 0 0 357* 3,580 55 2(1,2-DCA)
<br />'
<br /> MW-4 <05 <0 5 <0 5 <1 0 <0 05 <0 5 <0 5 -<20
<br /> MW-5 <05 <0 5 <0 5 <1 0 <0 05 <0 5 <0 5 -<20
<br /> MW-6 <05 <0 5 <0 5 <1 0 <0 05 <0 5 <0 5 -<20
<br /> I MW-7 <05 <0 5 <0 5 <1 0 <0 05 <0 5 <0 5 -<20
<br /> MW-9 <05 <05 <05 <10 <005 <05 <05 -<20
<br /> MW-10 <05 <05 <05 <10 <005 <05 <05 -<20
<br /> MW-11 <05 <05 <05 559 12 285 <05 -<20
<br /> MW-12D <05 <05 <05 <10 <005 <05 <05 -<20
<br /> SVE-4 63,000 53,600 1 3,970 17,850 355 317,000 <500-<20,000
<br /> Bold analytical data exceed California MCL(Maximum Contaminant Level)
<br /> *=The sample chromatogram does not mau,h the standard gasoline chromatogram
<br /> Units Analytical
<br /> mg/L=milligrams per liter_pai is per million(ppm) B T E,X=benzene,toluene,ethyl benzene,total xylenes
<br /> pg/L=micrograms per htei =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 (DIPS) ethyl tertiary bury[ ether —
<br /> (ETBE) tertiary amyl meth}l ether (TAME) 1 2-dic_hloroethane (I 2-DCA),
<br /> 1,2-dibromoethane(1 2-EDB)
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<br /> CONDOR
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