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Mr Harlin Knoll Page 2 of 3 2.2 Groundwater Monitoring and Sampling Monitoring wells MW 1 through MW4 were monitored and sampled on March 14, 2002 Groundwater elevations were calculated by measuring the depth to groundwater in each well and subtracting from the respective wellhead elevation The depth to water in the wells ranged from 6 26 to 7 64 feet below ground surface (bgs) The groundwater surface rose an average of 1 88 feet between December 13, 2001 and March 14, 2002 The direction of groundwater flow beneath the site was somewhat irregular based upon the March 14, 2002 data A potentlometric surface map is presented on Figure 2 An groundwater mound was apparent in the vicinity of well MW 1 Since the wells were installed in May 2001, the direction of groundwater flow has been toward the southwest and the northwest Groundwater monitoring data are summarized In Table 1 Monitoring data sheets are included in Attachment B Monitoring wells MW 1 through MW4 were purged a minimum of three well casing volumes of water prior to sampling The physical parameters temperature, pH, and electrical conductivity were measured during the purging process Samples were collected after the physical parameters had stabilized and water levels had recovered to at least 80% from pre-purged levels Purged groundwater was contained in appropriately labeled DOT-approved 55-gallon drums The drums are currently being stored onsite pending disposal Purge logs are included In Attachment A Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (ELAP 42359) Samples were analyzed for the presence of TPHg using EPA method 8015K BTEX using EPA method 8020, and oxygenated gasoline additives, 1,2-DCA, and EDB using EPA method 8260B 3.0 GROUNDWATER ANALYTICAL RESULTS No TPHg or BTEX were detected in any site well for the fourth consecutive sampling event Methyl tert butyl ether (MTBE) was the only chemical of concern detected at the site MTBE was detected in wells MW1, MW3 and MW4 at 79 parts per billion (ppb), 510 ppb and 94 parts ppb, respectively Analytical results are summarized in Table 2 MTBE concentrations over time in site wells are illustrated on Figure 3 Attachment C contains laboratory reports and chain of custody documentation 4.0 SUMMARY AND CONCLUSIONS • Groundwater levels at the site rose an average of 1 88 feet since the last round of sampling Groundwater flow beneath the site on March 14, 2002 was somewhat irregular based upon depth to groundwater measurements • MTBE was the only analyte of concern detected at the site during this round of sampling MTBE levels increased somewhat between December 2001 and March 2002 in wells MW 1, MW3 and . MW4, but remained below the detection limit(<2 0)in well MW2 • Cumulative groundwater analytical results suggest that no petroleum hydrocarbons are barnyard/reports/q=/1QM2002 doe