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Mr Harlin Knoll Page 2 of 3 • 5, 2002 and March 4, 2003 Groundwater generally flowed west-northwest with an average gradient of 0 0009 ft/ft, or approximately 5 feet per mile A potentlometric surface map for March 4, 2003 is presented on Figure 2 Groundwater monitoring data are summarized in Table 1 Monitoring data sheets are included in Attachment A At least three well casing volumes of water were purged from monitoring wells MW1 through MW7 before sampling Temperature, pH, and electrical conductivity were measured during the purging process ,Samples were collected after the measured parameters stabilized and water levels recovered to at least 80% of pre-purged levels Purged groundwater was contained in appropriately labeled DOT-approved 55-gallon drums, which were stored onsite pending disposal Purge logs are included in Attachment A Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (FLAP #2359) Samples were analyzed for the presence of TPHg using EPA method 8015M, BTEX using EPA method 8021B, and oxygenated gasoline additives including 1,2-DCA and EDB using EPA method 8260B 2.2 Purgewater Disposal On March 18, 2003, American Valley Waste Oil, Inc (CAL000827878) removed and transported approximately 300 gallons of purgewater generated from groundwater monitoring activities to a permitted TSDF for proper disposal A copy of the non-hazardous waste manifest is included in Attachment A 3.0 GROUNDWATER ANALYTICAL RESULTS Methyl-tert butyl ether (MTBE) was the only chemical of concern detected above laboratory method detection limits (MDLs) Wells MW3, MW4, and MW5 contained MTBE at concentrations of 240 parts per billion (ppb), 26 ppb and 6 3 ppb, respectively No MTBE was detected above MDLs in wells MW 1, MW2, MW6, or MW7 Analytical results are summarized in Table 2 The estimated extent of MTBE in shallow groundwater beneath the site is illustrated on Figure 3 Attachment B contains laboratory reports and chain of custody documentation for groundwater samples collected in March 2003 4.0 SUMMARY AND CONCLUSIONS • Groundwater elevations at the site rose approximately one foot since least monitored in December 2002 Groundwater beneath the site flowed west-northwest at a gradient of approximately five feet per mile • Total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd) and BTEX constituents have never been detected above MDLs in any site well MTBE was the Monly chemical of concern detected during this sampling event G\GROUNDZE\Barnyard-Mamer\Rcports\QMR\2003\1QM2003 doc