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In July 1994, a RESNA field geologist observed the drilling of four additional groundwater monitoring wells (MW4, MW5, MW6, and MW7) at the site to further characterize subsurface conditions Groundwater samples collected from these additional wells contained no detectable petroleum hydrocarbons A detailed discussion of the Phase 2 Subsurface Investigation can be found in RESNA's "Summary Report, July 1994 Investigation,"dated August 26, 1994 In PHS/EHD correspondence dated March 1995, regulatory approval was given to sample wells MW3 and MW5 and wells MW4, MW6 and MW7 on an alternating semi-annual basis MW1 and MW2 were to be sampled every quarter, conditions permitting To further define the extent of residual soil contamination in the vicinity of the former underground fuel storage tank (UST), Smith Technology supervised the advancement of four soil bonngs (SB-1, SB-2, SB-3, and SB-4) on February 29, 1996 to depths of approximately 16 to 26 feet below ground surface (bgs) Total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX) were detected above method detection limits at low to moderate concentrations in samples collected at depths between 10 and 15 feet bgs in bonngs SB-1, SB-2, and SB-3 A detailed discussion of this subsurface investigation can be found in Smith Technology's"Subsurface Investigation Report, " dated April 30, 1996 GROUNDWATER MONITORING AND SAMPLING Smith Technology personnel performed groundwater monitoring and sampling on October 3, 1997 Field work consisted of servicing the passive skimmer paced in well MW2, measuring the depth-to-water in wells MW1, MW2, MW3, MW4, MW5, MW6, and MW7, using an electronic water/product interface probe to determine if free product was present, sampling free product from the product skimmer, and purging and sampling wells MW1, MW2, MW4, MW6, and MW7 Static groundwater elevations were measured in each morutonng well on October 3, 1997 Groundwater was measured at an average of approximately 12 84 feet below grade The groundwater gradient map was created with the October 3, 1997 data using a computer kriging program The gradient map, presented as Figure 2, depicts a west-southwesterly groundwater gradient averaging 0 002 ft/ft or approximately 10 6 feet/mile Fluid level measurements indicate groundwater flow direction beneath the site during this reporting period is generally consistent with historical data Groundwater has decreased an average of 0 26 feet since the previous measurements were collected in June 1997 Groundwater monitoring data are summarized in Table l On October 3, 1997, free product samples were collected by Smith Technology from the passive skimmer installed in well MW2 It should be noted that the product sample collected from the site's passive skimmer reservoir was collected as a duplicate to a product sample collected by Ms Mary Meays of PHS/EHD • 943341QUARTLY\3QR-1997 DOC 2 3MTN