SITE INFORMATION AND CORRESPONDENCE

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Mr. Andrew Smith • - 2 - • 4 June 2004 a. The SCM does not include the possibility of discharges during refilling of the AGTs. b. The SCM does not adequately explain how 190,000 micrograms per liter (µg/1) of methyl tertiary butyl ether (MTBE) in monitoring well MW-2 could be from USTs removed in October 1991. Although MTBE was added to gasoline in 1991, only two to 11 percent was added to gasoline prior to 1991. The high MTBE concentrations detected at the site are likely due to the higher percentage of MTBE added to gasoline,which started in late 1991 as opposed to the low percentage required when the USTs were active prior to October 1991. C. The SCM does not include monitoring well MW-4, which is downgradient of the USTs and has detections of MTBE ranging from 1.4 to 48 µg/1, in the cross- sections provided in the Report. Based on the concentrations of MTBE in MW-2 and MW-3, which range from 7.9 to 190,000µg/1, the concentrations in MW-4 would be higher if the pollution originated from the USTs. H&H Marina previously argued that the retaining wall diverted the pollution to the south of the wall and around MW-4, yet the cross-section figures focus downgradient of the center point of the wall instead of the area where hydrocarbon pollution could have potentially been diverted. d. The SCM does not adequately explain why the highest concentrations in groundwater are detected from samples collected near the AGTs. Furthermore, the cross-sections showing concentrations of constituents of concern in groundwater do not show the core of pollutants leading or trailing from the former USTs. e. Concentrations of MTBE and total petroleum hydrocarbons (TPH) as gasoline continue to fluctuate in accordance with groundwater elevations. However, the concentrations are not decreasing as would be expected from a release more than 12 years ago. The SCM needs to explain why concentrations in groundwater are not decreasing and why the soils near the former USTs "may have flushed MTBE"but not flushed the pollution for the other areas of the site. f. The SCM does not include a discussion of when the AGTs were installed, how the AGTs are constructed(each tank has three compartments), the capacity of the AGTs and each compartment of the tank,what each compartment of the tank contains, the estimated refilling of the AGTs (gasoline versus diesel), how the tanks are refilled, when MTBE-free fuels were first utilized at the site, and the schematics for the piping from the AGTs to the dispenser(s). g. The SCM points out a discrepancy between the detections of gasoline versus diesel, however, there is insufficient TPH as diesel data to make a comparison.