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J + jMs. Dot Lofstrom • Page 2 last monitored on August 28, 2001. Groundwater elevation data are summarized in Table 1. Prior to sampling, monitoring wells MW 1 and MW2 were purged of a minimum of three well casing volumes. During the purging process temperature, pH and electrical conductivity parameters were measured. Samples were collected after parameter stabilization and an 80% minimum water level recovery of pre-purge levels. The samples were subsequently placed into an ice chest cooled to approximately 4°C for storage. Purge water was contained in appropriately labeled DOT-approved 55-gallon drums. The drums are currently being stored onsite. Purge logs are included in Attachment A. Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (ELAP 42359). Analysis consisted of gasoline oxygenate additives, 1,2 DCA and EDB using EPA method 8260, BTEX using EPA method 8020, and TPHg using modified EPA method 8015. GROUNDWATER ANALYTICAL RESULTS TPHg, which has been at non-detectable levels in well MW since July 1996, was detected at a concentration of 89 parts per billion (ppb) during this event. Benzene concentrations in this well continue to be non-detectable. Ethylbenzene was detected at a concentration of 2.5 ppb while 0 methyl Pert butyl ether (MTBE) was detected at a concentration of 20 ppb. No other gasoline compounds, oxygenate additives, EDB or 1,2 DCA were detected. In well MW2, TPHg, BTEX, gasoline oxygenate additives, EDB and 1,2 DCA were not detected for the second consecutive event. Analytical data are summarized in Table 2. Laboratory data reports and chain of custody documentation are included in Attachment B. A graph depicting MTBE concentrations over time in well MWl is included in Attachment C. SUMMARY Wells MW 1 and MW2 were monitored and sampled for TPHg, BTEX, gasoline oxygenates and lead scavenging fuel additives. Depth to water measurements indicated a drop in the potentiometric surface since the last monitoring event. Groundwater samples collected from well MW 1 contained low levels of TPHg, ethylbenzene and MTBE. MTBE in well MW 1 was detected at a concentration slightly above the primary maximum contaminant level (MCL) of 13 ppb. No analytes of concern were found in well MW2 for the second consecutive event. CONCLUSIONS The lateral and vertical limits of petroleum hydrocarbons and MTBE in MW 1 have been defined, verified, and are of limited extent. No petroleum hydrocarbons, gasoline oxygenates, EDB or 1,2 DCA are present in well MW2. Groundzelva11eyvw14gm2001