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• 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 66 38 to 76 36 feet below ground surface (bgs) The groundwater potentiometnc surface elevation averaged approximately 28 21 feet bgs during this monitoring event The groundwater elevation has increased approximately 0 98 feet since the last sampling event in February 2000 The groundwater flow direction during this reporting period is toward the southwest with a hydraulic gradient of approximately 0 03 ft /fl A summary of data regarding groundwater levels measured through June 1,2000 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 June 1, 2000, is presented on Figure 3 and summarized in Table 2 TPHg and BTEX were present at detectable concentrations in five of the nine samples submitted for analysis Chemical analytical results indicate the highest concentrations of TPHg and benzene are in the vicinity of monitor wells MW-3 and MW-4 TPHg concentrations in groundwater samples ranged from 458 micrograms per liter(ug/L) in monitor well MW-3,to Iess than detectable Ievels in samples collected from monitor wells MW-2, MW-6 through MW-8, and MW-10 Benzene concentrations ranged from below the . laboratory method detection limit in monitor wells MW-2, MW-6 through MW-8, and MW-10, to 90 5 ug/L in MW-3 MTBE concentrations in groundwater samples ranged from below the laboratory method detection limit in monitor wells MW-6 through MW-10,to 9 3 ug/L in a sample collected from monitor well MW-4 Attachment II contains photocopies of the laboratory analytical report and the chain-of-custody form Approximately 3 64 feet of liquid phase hydrocarbon (LPH) was detected in MW-1 during this monitoring event The physical appearance (clear) and its presence in the subsurface vapor extraction piping suggest that the LPH is the result of condensed soil vapor Asa precaution,the site inventory records and leak detection systems were checked Inventory records and leak detection systems appeared normal The LPH is currently being removed from MW-1 by hand bailing methods and the use of a passive, down-hole petroleum skimmer A total of approximately 10 gallons of LPH has been removed from MW-1 since its detection in February 2000 Purge Water Purge water generated during groundwater purging was transported by Integrated Waste Management, Inc to Seaport Environmental, in Redwood City, California, for treatment and disposal PmJects Mere Ol6i. kcfordQ200 2 SECOR 077 41737 0033 MY 20 2000