SITE INFORMATION AND CORRESPONDENCE

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Ms. Mary Meays Page 2 February 25, 1993 Investigations at Site #1 indicate that the maximum concentrations of TPH-G and Benzene observed in the soils were 280 ppm and 0.19 ppm, respectively. These levels were measured in a soil sample obtained from the bottom of the tank excavation. TPH-G was encountered in soils at only two other points, both of which are within eight feet of the tank excavation; these soils had TPH-G concentrations of 1.1 and 0.002 ppm, respectively. Benzene was only detected in the soil sample from the tank excavation and was not detected elsewhere. Data obtained from well borings indicates that the maximum vertical extent of TPH-G at concentrations of 1.0 ppm or more is approximately 18 feet below grade. Based on the soil data obtained from Site #1, the radius of soil contamination around the tank excavation has been defined along three of the four sides of the tank excavation. The only side of the tank excavation where soil samples have not been obtained is to the east, where the warehouse building is located. However, based on the information provided from seven sampling locations, the lateral extent of TPH-G in soil at concentrations greater than or equal to 1.0 ppm is no more than 18 feet from the northern, western and southern edges of the tank excavation. Since the extent of the 1.0 ppm line for TPH-G has been defined and appears to form a circle, it is highly probable that this circle continues underneath the warehouse building. There is no reason to assume that the extent of soil contamination under the building should be further from the tank excavation than has been defined on the three other sides. Groundwater Groundwater at Site #1 has also been the subject of investigation activities during three different periods of time, beginning in 1988. Groundwater has been characterized by the analysis of water samples obtained from the tank excavation, 13 soil-gas survey locations, and 5 groundwater monitoring wells. The maximum concentration of TPH-G and Benzene were measured at 520 ppm, and 400 ppm, respectively. These maximum concentrations were measured from a water sample that was taken at point M during the soil-gas survey. This sample point is relatively close (less than eight feet) to the south side of the tank excavation. Lower concentrations of TPH-G and Benzene were detected at other sampling points that were relatively close to the tank excavation. Concentrations of TPH-G and Benzene detected at these other sampling locations were less than 20 ppm and 2.9 ppm, respectively.