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�J Groundwater Elevation Data Depth to groundwater was obtained from the existing groundwater monitor wells at the site using a water level indicator graduated to 0 01 foot The depth to groundwater measurement was converted to a groundwater elevation for each well and used to construct a groundwater elevation contour map (Figure 2),and calculate the local groundwater flow direction and hydraulic gradient Groundwater at the site was measured at depths between 67 76 to 76 83 feet below ground surface (bgs) The groundwater potentiometric surface elevation averaged approximately 27 58 feet bgs during this monitoring event The groundwater elevation has decreased approximately 129 feet since the last sampling event in November 2000 The groundwater flow direction during this reporting period is toward the southwest with a hydraulic gradient of approximately 0 04 ft/ft A summary of data regarding groundwater levels measured through January 11,2001 is presented in Table 1 Copses of field observations documenting work performed at the site are presented in Attachment I Groundwater Analytical Results The distribution of groundwater sample analytical results obtained from monitor wells at the site on January 11, 2001, is presented on Figure 3 and summarized in Table 2 TPHg and BTEX were present at detectable concentrations in four of the ten samples submitted for analysis The highest concentration of petroleum hydrocarbons is in the vicinity of monitor well MW-I TPHg concentrations in groundwater samples ranged from 85,100 micrograms per liter(ug/L)in monitor well MW-1, to less than detectable levels in samples collected from monitor wells MW-2, MW-3 and MW-6 through MW-10 Benzene concentrations ranged from below the laboratory method detection limit in monitor wells MW-2, and MW-6 through MW-10,to 129 ug/L in MW-1 MTBE concentrations in groundwater samples ranged from below the laboratory method detection limit in monitor wells MW-1, MW-2 and MW-6 through MW-8, and MW-10, to 16 ug/L in samples collected from monitor wells MW-4 and MW-5 Attachment II contains photocopies of the laboratory analytical report and the chain-of-custody form On January 11, 2001, liquid phase hydrocarbon (LPH) was not detected in MW-1 during this monitoring event and therefore was sampled LPH continues to be monitored and removed (if necessary) from MW-1 by hand bailing methods and the use of a passive, down-hole petroleum slimmer on a weekly basis A total of approximately 44 gallons of LPH has been removed from MW-1 since its detection in February 2000 Purge Water Purge water generated during groundwater purging is currently contained on-site in Department of Transportation rated 55-gallon drums and will be removed to a disposal/recycling facility during April 2001 C Mme 0,NWCkCWdQ101 2 56COR 077 41737 003 Apnl 16 2001