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Mr Harlin Knoll <br /> Page 2 of 2 <br /> t <br /> The samples were transported to Argon Laboratories (FLAP #2359) under thorn of custody protocol and <br /> analyzed for TPHg and BTEX utilizing EPA methods 8015M and 8021B, respectively Purged groundwater <br /> was contained in labeled Department of Transportation (DOT) approved drums pending disposal Copies of <br /> field purge logs and water level measurements are included in Attachment A <br /> Groundwater Analytical Results <br /> Elevated levels of dissolved gasoline constituents were detected in the groundwater samples collected from well <br /> MWS, and relatively low levels were detected in samples collected from well MW 1 No gasoline constituents <br /> were detected in the samples collected from wells MW3 and MW4 <br /> Well MW5 contained TPHg at a concentration of 48,000 parts per billion (ppb), benzene at 4,500 ppb, <br /> toluene at 580 ppb, ethylbenzene at 400 ppb, and xylenes at 2,700 ppb Well MW1 contained TPHg at a <br /> concentration of 460 ppb,benzene at 4 2 ppb, ethylbenzene at 18 ppb, and xylenes at 10 ppb No toluene was <br /> detected in well MWl Analytical results are summarized in Table 3 Laboratory data sheets and chain of <br /> custody documentation are included in Attachment B Figure 3 presents a benzene isoconcentration map <br /> utilizing the most recent analytical results Attachment C contains graphical representations of TPHg and <br /> benzene concentrations over time in site wells <br /> SUMMARY AND CONCLUSIONS <br /> Groundwater at the site flowed in an east-northeast direction The potentiometric surface at the site rose an <br /> average of 3 0 feet The water level lies above the screened interval in wells MW4 and MW5 <br /> No gasoline constituents were detected in wells MW3 and MW4 TPHg, benzene, ethylbenzene, and xylenes <br /> were detected at low levels in well MW 1 TPHg and BTEX were detected at elevated levels in well MW5, but <br /> the concentrations decreased from November 2002 levels and remain well below historic highs for that well <br /> Please contact John Lane at(209) 838-9888 if you have any questions or comments regarding this report <br /> Respectfully, <br /> Ground Zero Analysis, Inc <br /> - `Sean Garvey <br /> �' JOHN A <br /> Staff Geologist t_nNE <br /> No 6795 <br /> John P Lane <br /> CA Registered Geologist 6795 Off' CLl <br /> Attachments <br /> cc Mr Carl Knowles <br /> Mr Patrick D Riddle, Attorney at Law <br /> Mr James L L Barton, CRWQCB Sacramento <br /> G\GROUNDZEIKNOWLSS HAMIREP0RTSIQMR11QM2003 doc <br />