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Mr Martin Hams Page 2 of 3 '• SITE ACTIVITIES Activities at the site during the reporting period included monitoring groundwater levels in site monitoring wells, purging and sampling groundwater from site morutormg wells, and analyzing samples for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, total xylenes (BTEX), oxygenated gasoline additives, and the lead scavengers 1,2-dichloroethane (1,2-DCA) and ethylene dibromide (EDB) Measured Groundwater Elevations An experienced field technician measured the depth to groundwater in monitoring wells MW 1 through MW7 on December 10, 2004 Groundwater elevations were calculated by subtracting the measured depth to groundwater in each well from the respective wellhead elevation The depth to groundwater in the wells ranged from 5 53 to 6 39 feet below the tops of the well casings (btoc) The potentiometric surface in site wells rose an average of 0 47 feet between September 29, 2004 and December 10, 2004 As measured on December 10, 2004, shallow groundwater beneath the site generally flowed northwest at a gradient of 0 0009 feet per foot A potentiometric surface map generated from the December 10, 2004 monitoring data is shown on Figure 2 Groundwater monitoring data are summarized in Table I Monitoring data sheets are included in Attachment A Groundwater Sampling Procedures Monitoring wells MW1 through MW7 were sampled on December 10, 2004 The wells were purged of at least three well casing volumes prior to sampling The physical parameters of temperature, pH and electrical conductivity were measured during the purging process Groundwater samples were collected after the physical parameters stabilized and groundwater in the wells recovered to pre-purged levels The samples were placed into an ice chest refrigerated to approximately 4°C and transported to Argon Laboratories (FLAP #2359) under chain of custody protocol Well purge logs are included in Attachment A GROUNDWATER ANALYTICAL RESULTS Groundwater samples were analyzed for the presence of TPHg, BTEX, and oxygenated gasoline additives (including the lead scavengers 1,2-DCA and EDB) using EPA methods 801513, 8021B, and 8260B, respectively TPHg was detected in well MW2 at a concentration of 88 µg/L No TPHg was detected in any other site well Ethylbenzene was detected only in well MWI, at a concentration of 0 9 µg/L No other BTEX constituents were detected in any site well in December 2004 MTBE was detected in wells MW 1, MW2, MW3, and MW5 at concentrations of 2 8 µg/L, 1 9 pg/L, 4 9 pg/L, and 4 9 pg/L, respectively No MTBE was detected above the method detection limit(MDL)of 0 5 G 1GRQUNDZ$1TuffBuy\ReportslQMR1200414QM2004 doc