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' had occurred in the vicinity of the former gasoline tank, and that further investigation was <br /> iwarranted. <br /> ' On August 24 and 25, 1994, Remcor installed an additional seven soil borings and three <br /> monitoring wells to further define the lateral extent of soil and ground water <br /> ' contamination identified in the initial phase of work. <br /> On March 8, 1996, AGS installed three ground water monitoring wells to further define <br /> ' the lateral and vertical extent of contamination. Monitoring well MW-7 was installed in <br /> the upgradient direction to the southeast of the former UST pit. Monitoring well MW-8 <br /> was installed west of the former UST pit to assess ground water quality in that direction. <br /> ' These two wells were installed to a depth of 27 feet and 25 feet below grade, respectively. <br /> Monitoring well MW-9 was installed adjacent to the previously installed well MW-6 to <br /> determine the vertical extent of contamination. This well was installed to a depth of 45 <br /> feet below grade and sealed with bentonite between the depths of 38 feet and 28 feet. <br /> ' A remedial excavation was conducted during July and August, 1998. Approximately <br /> 1522 cubic yards of gasoline impacted soil was removed and aerated on-site. Monitoring <br /> wells MW-1, MW-2, MW-3, MW-4 and MW-8 were abandoned prior to beginning the <br /> excavation. On September 17, 1998, monitoring well MW-1A was installed near the <br /> former location of MW-1. <br /> 1.3 Geology <br /> The subsurface geology of the site was determined by logging soil samples collected at <br /> various intervals during the initial and supplemental site investigations. <br /> Dark brown silty clay dominates the stratigraphy from within one foot of the surface to <br /> the bottom of the borings. In general, fine sand was found within the silty clay unit near <br /> ' the bottom of the borings at an approximate depth of 20 feet. The moisture content <br /> increased with depth and reached saturation between 12 and 16 feet below grade. <br /> ' 1.4 Hydrology <br /> Groundwater at the site is contained in a semi-confined or unconfined aquifer typically 10 <br /> ' to 15 feet below grade. However, ground water was measured at an approximate depth of <br /> 8 feet bgs during the spring of 1998. Historically, groundwater at the site demonstrates a <br /> ' shallow gradient which slopes to the northwest. <br /> CA95DE-029 American Geological Services, Inc. <br /> 4 <br />