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f6 F F • Discussion Groundwater flow du=on is northerly at a flow gradient that is consistent with historically observed northerly flow trends (see Figure 1) Groundwater levels have declined about 0 5 feet in wells since the last quarter z Floating product was present in MW-3 (apparent thickness of 0 26 feet) and in MW-9 (apparent thickness of 0 51 feet) and a total of about 450 mi Miters was bailed and removed Since samples were collected and analyzed from those wells, the TPHG levels increased in wells MW-6 and MW-9 and decreased in MW-3 Benzene concentrations declined in Well MW-3 and only increased slightly in MW-9 MTBE oxygenates were not detected in any well Contaminant TPHG concentrations increased in MW-3 and MW-9 and a decline in groundwater levels suggesting a residual TPHG source in those wells vicinity Wells MW-3 and MW-9 have historically shown elevated TPHG concentrations on the site and observed fluctuations have been interpreted as local contaminant drainage and desorption from sediment near the casing Separate phase product was observed in MW-3 and MW-9 during this sampling event and is interpreted to anse from drainage within the capillary fringe and aquifer sediment Previous site study, including geophysical study for additional potential product sources did not reveal any subsurface strictures as possible tanks for product sources Previous observations indicate that product presence tends to diminish when groundwater levels rise during the ram:y months (aquifer recharge), and reappear during dry months(aquifer discharge) . The presence of petroleum product in MW-3 and MW-9 has not caused a concurrent large rise in BTEX volatile content that in our opinion indicates the dissolved plume of degraded fuel is relatively depleted in dissolved volatile constituents (see Figures 2, 3 and 4) The elevated dissolved data from MW-3 and MW-9 may be m part attributed to analysis of a water sample collected from a well containing sheen to mucor separate phase product Previous experience has shown that such a sample will tend to show very high dissolved contaminants due to the presence of the product in that well The interpreted location of the dissolved plume based on the historic groundwater flow and interpreted contour information continues to show essentially no net plume movement beyond the area immediately around Wells MW-3 and MW-9 Conclusions and Recommendations Groundwater flow direction was northerly under a low calculated gradient and water levels in monitoring wells had declined about 0 50 feet since the previous quarter In our opinion, the mapped contaminant dissolved plume continues to occur near the center of the site, sunilar to historic site observations and previous mvestigation reports submitted to FHS EHD Tun layers of separate phase product occurred in MW-3 and MW-9 The TPHG levels fluctuated in wells, with an increase in MW-3 and MW-9 Wright has completed and submitted an interim remedial action plan HUP (targeted in the vicinity of MW-3 and MW-9) subsequent to PHS EHD review of the CAP Wright has discussed the TRAP interim cleanup approach for submittal for PHS EHD review and scheduling The site is scheduled for continued quarterly monitoring at this time Page 3