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TreadweIER0110 The Site is underlain by silts and clays with some shallow silty sand layers Groundwater elevations in borings at the Site generally stabilized at 19 to 20 bgs However, no groundwater was encountered in Boring CSB-5, advanced during our recent investigation, which was 30 5 feet deep and left to stabilize for 24 hours During their June 2003 investigation, AGE advanced 8 borings (B-1 through B-8) and obtained groundwater grab samples from borings B-1 through B-4, and B-6 through B-8 (Figure 2) The water samples were analyzed for total petroleum hydrocarbons as gasoline (TPH-g) and as diesel (TPH-d) and for volatile organic compounds (VOCs) No compounds were detected in any of the water samples except from the sample collected from Boring B-3, located in the sidewalk ' adjacent to the Site along West Fremont Street The groundwater sample from Boring B-3 contained petroleum range hydrocarbons quantified in the range of TPH-g and TPH-d at concentrations of 17,000 and 12,000 micrograms per liter (ug/1) respectively, ethylbenzene at 1,300 ug/l, and xylenes at 2 090 ug/l (Table 1) Significant shallow soil contamination (less that 15 feet below ground surface (bgs)) was not encountered Concentrations of TPH-g were detected at B-3 in soil samples from 15 and 20 feet bgs at 2,000 and 12,000 milligrams per kilogram (mg/kg), respectively No source for the petroleum hydrocarbon contamination was identified during this investigation ' The Site was subsequently enrolled in the San Joaquin County UST program and characterization is currently being overseen by the San Joaquin County Environmental Health Department (SJCEHD) 4.0 SUBSURFACE INVESTIGATION Treadwell & Rollo prepared a 23 December 2003 workplan for the Site to advance up to six borings to collect soil and groundwater samples in the vicinity of AGE boring B-3 3 25971013 DGD 12 April 2004