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Mr Jeff Wong Page 3 of 5 . Groundwater flowed in a northeasterly direction with an average gradient of 0 0014 ft/ft An apparent groundwater depression previously measured in well MW4 was not apparent in March 2002, probably due to the destruction of the old water supply well A potentiometric surface map generated using the March 20, 2002 monitoring data is presented on Figure 2 Groundwater monitoring data are summarized in Table 2 Monitoring wells MW2 through MW9B were purged of at least three well casing volumes prior to sampling Temperature, pH and electrical conductivity were measured during the purging process Samples were collected after the physical parameters stabilized and water levels in the wells recovered to at least 80% of their pre-purged levels Purged groundwater was contained in appropriately labeled DOT-approved 55-gallon drums in accordance with 49 CFR part 172 and 40 CFR part 262 Groundwater samples collected from the monitoring wells were delivered under chain of custody protocol to Argon Laboratories (FLAP #2359) for analysis Field data sheets and purge logs are included in Attachment A 3.0 GROUNDWATER ANALYTICAL RESULTS The groundwater samples collected from the site were analyzed for total petroleum hydrocarbons as gasoline (TPHg)using EPA 8015M, benzene, toluene, ethylbenzene, total xylenes (BTEX) using EPA 8020, and oxygenated gasoline additives, ethylene dibromide (EDB) and 1,2-dichloroethane (1,2- DCA)using EPA 8260B A copy of the laboratory reports are included in Attachment D The two groundwater samples collected from the old water supply well contained approximately equal concentrations of benzene and methyl-t-butyl ether (MTBE) Benzene was detected at 1 6 parts per billion and 1 3 ppb from depths of 90 feet and 200 feet, respectively, and MTBE was detected at 1,100 ppb and 1,200 ppb No other constituents of concern were detected above laboratory method detection limits The results suggest that no vertical chemical gradient existed in the static water within the well casing No gasoline constituents were detected in monitoring wells MW7, MW8, or MW9B Well MW 1 contained free product and was not sampled TPHg was detected in wells MW2, MW3, and MW4 at 2,100 ppb, 240 ppb, and 700 ppb, respectively Benzene was detected in wells MW2, MW3, MW4 and MW6 at 54 ppb, 2 0 ppb, 21 ppb and 2 2 ppb, respectively MTBE was detected in wells MW3, MW4, MW5, and MW6 at 740 ppb, 14,000 ppb, 24 ppb and 2,100 ppb, respectively Toluene, ethylbenzene, and xylenes were detected at relatively low levels in well MW2 Analytical results are summarized in Table 3 Laboratory reports and chain-of-custody documentation are included in Attachment D The estimated extents of benzene and MTBE in the shallow aquifer are presented on Figures 3 and 4, respectively 4.0 SUMMARY AND CONCLUSIONS The measured free product in well MW 1 ranged from dust a sheen to a thickness of 0 03 feet during the reporting period Approximately 5 5 gallons of product/water mixture was removed from well MW 1 during the reporting period, bringing to 43 5 gallons the total volume of product/water mixture G\Data1GROUNDZEITULEBURGaeportslQMRV QM2002 doe