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Mr Michael Infurna Page 2 water was contained in properly labeled DOT-approved 55-gallon drums The drums are currently being stored onsite Purge logs are included in Attachment A Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (ELAP #2359) Analysis consisted of TPHg and TPHd using modified EPA method 8015B, gasoline oxygenate additives using EPA method 8260B, and BTEX using EPA method 8021B Groundwater Analytical Results BTEX, EDB and 1,2 DCA were not detected in any site wells TPHg, TPHd and gasoline oxygenates were not detected in wells MW1, MW2, MW4 and MW5 In well MW3, TPHg was detected at a concentration of 530 parts per billion (ppb) TPHd was detected at a concentration of 3,100 ppb Methyl-tert-butyl ether (MTBE) was detected at a concentration of 790 ppb Tert-butyl alcohol (TBA) was detected at a concentration of 46 ppb, and tent-amyl-methyl ether (TAME) was detected at a concentration of 2 4 ppb Analytical results are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation Graphs of TPHg, TPHd and MTBE concentrations over time in MW3 are included in Attachment C Summary o Groundwater levels at the site fell since the previous round of sampling The average groundwater gradient across the site was 0 002 ft/ft Groundwater flowed in a northeasterly direction This is the third consecutive quarterly monitoring event in which flow was toward the northeast BTEX, EDB and 1,2 DCA were not detected above laboratory method detection limits (MDLs) in any site well Gasoline oxygenates, TPHg and TPHd concentrations were less than MDLs in wells MW1, MW2, MW4 and MW5 • Relative to the previous sampling event, the concentration of TPHd in well MW3 increased an order of magnitude while the level of TPHg decreased by more than 50% Concentrations of MTBE detected in MW3 were similar to the previous event Low levels of TBA were detected in MW3 for the fourth time since sampling began Minor levels of TAME were detected in MW3 during this event Conclusions Both the dissolved contaminant plume and residual soil contamination are localized in the vicinity of well MW3, and are of very limited extent No dissolved contaminants have ever been detected in any perimeter well Only well MW3 has ever had detectable concentrations of any target analytes Cumulative data indicates that the plume is not migrating, and dissolved contaminant concentrations are stable to decreasing (Attachment C) G 1GROUNDZE\WOOLSEY CHTQMR1200313QM2003 doe