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� v <br /> ASSOCIATES I NC <br /> methodologies, and oxygenate fuel additives utilizing EPA 8260 methodology The analytical <br /> results for groundwater samples are summarized in Table 3 Laboratory data sheets and chain-of- <br /> custody documentation are included in Appendix C <br /> 3.0 SUBSURFACE CONDITIONS <br /> 3.1 Geolory <br /> ' Soil in bonngs SB7, SB8, S139, SB 10, SB 11, and SB 12 consisted of poor to well graded sand and <br /> silty sand from the surface to between 20 and 25 feet bgs Some sandy silt was encountered in <br /> borings S137, SB 11, and SB 12 Soil in boring SB9 from depths between 21 and 24 feet bgs and <br /> ' 26 feet bgs consisted of silty clays <br /> The CPT log extends to approximately 16 feet bgs From approximately 3 to 4 5 feet bgs the soil <br /> ' is described as silty sand to sandy silt From 4 5 feet to approximately 11 feet the soil is described <br /> as sand to silty sand From approximately 11 feet to 16 feet where probe refusal occurred, the <br /> soil is described as sand with a thin layer of soil located at 13 7 feet described as sand to silty <br /> sand <br /> 4.0 ANALYTICAL RESULTS <br /> 4_1 Soil Analytical Results <br /> 1 Soil samples collected from borings S137, S138, SB9, SB 10, SB 11, and SB 12 did not contain <br /> detectable concentrations of TPHg, BTEX or fuel oxygenates including methyl tertiary butyl ether <br /> ' (MTBE) Analytical results of soil samples are summarized in Table 1 The estimated lateral <br /> extent of TPHg in soil is generally limited to the vicinity of the former USTs and is shown on <br /> Figure 4 <br /> kr 4.2 Groundwater Analytical Results <br /> The groundwater samples collected from borings SB7, SB8, S139, S1310, SBI 1, S1312, and CPT1 <br /> did not contain detectable concentrations of TPHg, BTEX or fuel oxygenates , Analytical results <br /> of soil samples are summarized in Table 2 The estimated lateral extent of TPg in groundwater <br /> ' is limited to the vicinity of the site and is shown on Figure 5 The estimated vertical extent of <br /> impacted groundwater appears to be limited to the shallow aquifer and is present at depths less <br /> ' than 45 feet bgs <br /> 5.0 WELL SURVEY <br /> ATC reviewed San Joaquin County groundwater well construction logs to identify any <br /> groundwater wells located within a 2,000-foot radius of the site The search revealed twelve <br /> potential wells located within approximately 2,000 feet of the site The approximate well <br /> locations are shown on Figure 3 <br /> ! w A49811reporis\Add_Inv doc 4 <br />