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Ms Lori Duncan Page 2 of 4 • product from the well The waste was stored on site in accordance with 49 CFR part 172 and 40 CFR part 262 Table 1 summarizes product thickness measurements and product removed Field notes associated with product bailing, including a chart showing the measured product thickness in the well over time are included in Attachment 1 2.2 Groundwater Monitoring Water level elevations were monitored in wells MWI through MW7 on June 3, 2004 The depth to water and depth to product in well MW3 were measured using an electronic water/hydrocarbon interface probe Depths to water in other site wells were measured using an electronic water level indicator 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 on June 3, 2004 ranged from 25 04 feet below the top of the well casing (btoc) in well MW3 (corrected for the presence of free product) to 26 09 feet btoc in well MW5 Groundwater flowed in a northeasterly direction with a calculated gradient of 0 0034 feet per foot (approximately 18 feet per mile) A potentiometric surface map for June 3, 2004 is shown on Figure 2 Groundwater monitoring data are summarized in Table 2 Monitoring data sheets are included in Attachment 2 2.3 Well Purging An experienced Ground Zero technician purged wells MWI through MW7 on June 3, 2004 using dedicated, disposable bailers The technician purged a minimum of three well casing volumes of water from each well and measured physical parameters of temperature, pH and electrical conductivity during the purging process Purging was terminated at each well after the measured parameters stabilized All downhole equipment was decontaminated between wells by washing with a solution of laboratory-grade detergent, and then double rinsing with clean rinse water 2.4 Groundwater Sampling Groundwater samples were collected from each well after physical parameters had stabilized and the water in the well had recovered to pre-purged levels Samples were placed in an ice chest at a temperature of 4° Centigrade and submitted to Argon Laboratory under chain of custody protocol The samples were analyzed for the presence of VOCs pursuant to the existing groundwater monitoring and sampling program Field development/purge logs are included in Attachment 2 3 0 GROUNDWATER ANALYTICAL RESULTS • Tetrachloroethene (PCE) was detected in wells MWI, MW2, MW4, MW5, MW6, and MW7 at G 1GROUNDZE\GASSARblreports\QMR1200412QM2004 doe