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Ms Lori Duncan Page 2 of 3 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 charts showing the measured product thickness in the well over time and the depth to fluid thickness in the wel I over time are included in Attachment 1 22 Groundwater Monitoring Water level elevations were monitored in wells MW 1 through MW7 on March 3, 2005 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 March 3, 2005 ranged from 25 25 feet below the top of the well casing (btoc) in well MW3 (corrected for the presence of free product)to 26 29 feet btoc in well MW5 Groundwater flowed in a northeasterly direction with a calculated gradient of 0 0036 feet per foot (approximately 19 feet per mile) A potentiometric surface map for March 3, 2005 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 MW1 through MW7 on March 3, 2005 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 TPHg, TPHd, BTEX, and 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 MW1, MW2, MW4, MW5, MW6, and MW7 at concentrations of 8 3 micrograms per liter (lig/L), 7 5 WL, 4 1 }tgll,, 2 8 gg/L, 43 gg/L, and 100 gg/L, respectively No PCE was detected in well MW3 (<20 gg/L) Cis-1,2-Dtchloroethene (cis-1,2-DCE) ranged from <0 5 gg/L in wells MW2 and MWS to 22 gg/L in well MW3 Chloroform ranged from 0 7 gg/L in well MW7 to 2 4 gg/L in well MW1, but was not detected in well MW3 (<2 0 gg/L) Trichloroethene(TCE) was detected only in wells MW6 (1 3 gg/L) and MW7 (2 9 gg/L) G 1GROUNDZ£1GABBARDIreports%QMR120051iQM2005 doc