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Ms Lori Duncan Page 2 of 3 • 1 Monitoring data sheets are included in Attachment A Pnor to sampling, monitoring wells MW 1 through MW4 were purged of approximately four to six well casing volumes 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 water recovered to least 80% of pre-purged levels The samples were placed into an ice chest cooled to approximately 4°C and transported to Argon Laboratories (ELAP 92359) 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 8015M, 8020, and 8260B, respectively No TPHg or BTEX were detected in either well MW3 or well MW4 for the fourth consecutive sampling event TPHg was detected in wells MW 1 and MW2 at concentrations of 560 parts per billion (ppb) and 56 ppb, respectively Benzene was detected in wells MW 1 and MW2 at concentrations of 1 2 ppb and 0 6 ppb, respectively Methyl Cert butyl ether (MTBE) was detected in wells MW2, MW3 and MW4 at concentrations of 2 9 ppb, 3 6 ppb and 4 2 ppb, respectively No other oxygenated gasoline additives or lead scavengers were detected in any site well Analytical results are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation Summary Groundwater levels beneath the site fell an average of 0 19 feet since last monitored in September 2001 No wells exceeded the Primary Maximum Contaminant Level (MCL) of 13 ppb for MTBE or the secondary MCL of 5 0 ppb Only well MW 1 contained benzene at a level exceeding the primary MCL of 1 0 ppb for benzene Well MW 1 contained benzene at 12 ppb Recommendations Ground Zero recommends the site be considered for closure as a low risk site based upon the following observations • Historically, the pnmary MCL for MTBE has been equaled or exceeded in only three of sixteen samples collected from site wells, • Current levels of MTBE are below both the primary MCL and secondary MCL in all site wells, • The primary MCL for benzene has been marginally exceeded in only two site wells, • Currently, only well MW at 12 ppb exceeds the primary MCL for benzene(1 0 ppb) 0 1Dat.R1GROUNDZE1Tul3$oylRepoaslQMR14QM2001 doc