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� 7 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 77 to 76 00 feet below ground surface (bgs) The groundwater potentzometric surface elevation averaged approximately 28 30 feet bgs, during this monitoring event The groundwater elevation has increased approximately 0 72 feet since the last sampling event in January 2001 The groundwater flow direction during this reporting period is toward the southwest with a hydraulic gradient of approximately 0 02 ft/ft A summary of data regarding groundwater levels measured through April 27, 2001 is presented in Table 1. Copies 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 April 27,2001,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-1. TPHg concentrations were below method detection limits for all wells sampled during this monitoring event Benzene concentrations ranged from below the laboratory method detection limit in monitor wells MW-2, MW-3, MW-5 through MW-8, and MW-10 to 0 56 micrograms per liter (ug/L) in MW-9 MTBE concentrations in groundwater samples ranged from below the laboratory method • detection limit in monitor wells MW-2 through MW-4 and MW-6 through MW-10, to 0 9 ug/1L in MW-5 Attachment It contains photocopies of the laboratory analytical report and the chain-of- custody form Approximately 2 9 feet of liquid phase hydrocarbon (LPH) was detected in MW-1 during this monitoring event The LPH is currently being removed from MW-1 by hand bailing methods and the use of a passive, down-hole petroleum skimmer on a weekly basis The LPH thickness has decreased in MW-1 since it was first observed in February 2000 A total of approximately 49 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-gaIIon drums and will be removed to a disposal/recycling facility during October 2001 SITE REMEDIATION Construction of a soil and groundwater remediation system was completed at the site in December 1999 The remediation system consists of seven soil vapor extraction (SVE) wells (W-1, W-3 C rime 0.NL k6wdQ201 2 SECOR 077 41737 003 July 31 2001