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Trea&MI&Rdlo <br /> 3.2 Previous Investigations <br /> In June 2003 Advanced GeoEnvironmental (AGE) advanced eight borings (B-1 through B-8) <br /> and obtainedgroundwater grab samples from Borings B-1 through B-4,and B-6 through B-8 <br /> (AGE, 2003a). AGE Boring B-3, located in the sidewalk adjacent to the Site along West <br /> Fremont Street was the only boring with detectable concentrations of petroleum hydrocarbons as <br /> gasoline (TPH-g) and diesel (TPH-d) in soil or groundwater(AGE, 2003a). Tables 1 and 2 <br /> summarize the analytical results for soil and groundwater, respectively. Following this <br /> investigation, the Site was enrolled in the San Joaquin County UST program overseen by the <br /> SJCEHD. <br /> Treadwell &Rollo prepared a 23 December 2003 workplan for the Site to advance up to six <br /> borings to collect soil and groundwater samples in the vicinity of AGE Boring B-3. Between <br /> 15 and 2 - <br /> 0January 2004, six borings (CSB-I through CSB-6)were advanced and soil samples <br /> were collected from all six borings, while groundwater samples were collected from Borings <br /> CSB-1 through CSB-4. Figure 2 shows the boring locations. The highest concentrations of <br /> petroleum hydrocarbons in soil and groundwater were detected in Boring CSB-2, located <br /> approximately 23 feet east of AGE Boring B-3. Tables 1 and 2 summarize the analytical results <br /> of Treadwell & Rollo's investigation for soil and groundwater, respectively. <br /> 3.3 Soil and Groundwater Remediation <br /> 3.3.1 UST Excavation <br /> On 28 April 2004, the three USTs present in the sidewalk adjacent to the Site were removed, and <br /> during June 2004, a shored excavation was dug 43 feet long by 14 feet wide by 23 feet deep <br /> (Figure 2). Approximately 425 cubic yards of soil were excavated and disposed of, and <br /> 20,000 gallons of groundwater pumped out and disposed of under permit to the sanitary sewer. <br /> The excavation was subsequently backfilled (Treadwell &Rollo, 2004b). Analytical results for <br /> the soil and groundwater samples collected at the bottom the excavation are presented in <br /> Tables 1 and 2 respectively. <br /> 3 <br /> 25970122.DGD 14 February 2005 <br />