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Environmental Mr.Harlin Knoll Resources 23 April 1998 Management Page 2 surface (bgs) to determine the depth of impacted soil. In addition, ERM pumped approximately 6,000 gallons of ground water from the tank excavations and collected ground water samples for analysis. The analytical results of these additional sampling activities were reviewed by ERM. The information generated during the tank removal activities and the Phase II Environmental Site Assessment (Phase 11 ESA) indicated that the majority of the impact caused by the two former USTs occurs within site ground water. Based on this information, ERM developed a sampling and analysis plan to characterize the extent of TPH-g impact to soil and ground water in the vicinity of the two tanks. The scope of this investigation was discussed with the County in a phone conversation on 19 March 1998. The County agreed with the proposed sampling strategy. In accordance with the sampling strategy discussed with the County, ERM conducted additional investigation activities on 2 and 3 April 1998. To determine the extent of soil impact in the vicinity of the former USTs, soil samples were collected in the unsaturated zone (approximately 3 to 5 feet bgs) and directly above the water table (approximately 7 feet bgs) from two locations (HB-15 and HB-16) surrounding UST #1 (Figure 1) and four locations (HB-11 through HB-14) surrounding UST #2 (Figure 2). To characterize the extent of impact to site ground water, ERM collected ground water hydropunch samples from five locations (HB-6 through HB-10) around UST #1 (Figure 1) and five locations (1-113-1 through HB-5) around UST #2 (Figure 2). In addition, ERM collected soil samples directly above the water table (approximately 5 to 7 feet bgs) from each of the ground water locations (HB-1 through HB-10) to determine the extent of ground water impact to soil. Based on the results of this investigation and previous investigations, ERM evaluated the need for further soil and ground water investigation activities and soil removal at the site. Based on the TPH-g and benzene, toluene, ethyl benzene, and xylenes (BTEX) concentrations present in the soil and ground water at the UST#2 location and discussions with the county, ERM believes that no further soil or ground water removal activities are necessary at this location. For the UST #1 location, no further ground water removal activities are required; however, ERM believes that additional soils should be removed along the northern and eastern boundaries of the tank excavation based on the soil samples collected in these areas.