SITE INFORMATION AND CORRESPONDENCE

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Ms. Mary Meays Page 3 February 25, 1993 Based on the water sample data obtained, the lateral extent of TPH-G in the groundwater at concentrations greater than or equal to 1.0 ppm is 24 feet from the edges of the tank excavation. As was previously discussed for the soils, this limit of groundwater contamination has been defined on three sides of the tank excavation, but not on the fourth side east of the excavation and under the warehouse. Since we have defined the extent of contamination on three sides and it generally forms a circle, it is highly probable that the maximum lateral extent of groundwater contamination beneath the building is defined by completing the circle. Thus, we estimate that 24 feet from the eastern edge of the tank excavation is the maximum lateral distance that TPH-G would be measured in concentrations at or above 1.0 ppm. ERM agrees with PHS/EHD that TPH-G and related Benzene, Toluene, Ethylbenzene and Xylene (BTEX) components continue to be detected at MW- 5, although at relatively low concentrations. These constituents were also detected in MW-4, but were not detected during Fourth Quarter 1992 groundwater monitoring activities. As discussed in our Fourth Quarter 1992 groundwater monitoring report that we sent to you on January 14, 1993, a general trend has been established over the last 20 months in which the concentrations of TPH-G and BTEX compounds have diminished through time. FORMER TANK SITE #2 Attachment B shows the figures and tables for Former Tank Site #2 (Site #2) that we presented to you during our December 18, 1992 meeting. The display consists of a groundwater elevation map; two maps showing maximum concentrations of TPH-G, TPH as Diesel (TPH-D), and Benzene measured in soils and groundwater, respectively; a geologic cross section; and summarized groundwater monitoring data. Soils Soils at Former Tank Site #2 (Site #2) have been the subject of investigation activities during two different periods of time, beginning in 1991. Soil in the vicinity of Site #2 has been characterized by the analysis of data obtained from the tank pit excavation, and the installation of four groundwater monitoring wells. At Site #2 the following constituents (and their maximum concentrations) were detected in soils: TPH-G (1,200 ppm); TPH-D (180 ppm); and benzene (31 ppm). The maximum TPH-G concentration was measured in a soil sample taken from the base of the tank during excavation, and at MW-3A at a depth of 7.5 feet below grade. The maximum TPH-D and benzene concentrations