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CAMBRIA <br /> (BTEX), and fuel oxygenates (methyl tertiary butyl ether (MTBE), tertiary amyl ether, <br /> di-isopropyl ether, ethyl tertiary butyl ether, and terliary amyl methyl ether). <br /> None of the soil samples contained detectable levels of benzene, toluene, or fuel oxygenates. <br /> Nine of the 14 soil samples did not contain d testable levels of TPHg, BTEX, and fuel <br /> oxygenates. Three of the soil samples contained only xylenes at concentrations ranging from I <br /> 0.0159 to 0.0296 parts per million (ppm). The remaining two soil samples contained TPHg at <br /> concentrations of 4.59 and 54.7 ppm. Ethylbenz ne and xylenes were also detected in these <br /> samples at concentrations ranging from 0.138 to 1.5 5 ppm. <br /> Four soil borings (SB-1 through SB-4) were drilled at the site during July 2001 to further assess <br /> the vertical and lateral extent of gasoline constitue is in the soil and to determine if groundwater <br /> beneath the site was impacted. Soil analytical results from this investigation suggested the lateral <br /> extent of impacted soil is delineated and confuied. to the vicinity of boring SB-1. The <br /> groundwater sample collected from boring SB-1 co atained 780 parts per billion (ppb) TPHg and <br /> did not contain benzene or MTBE. <br /> WORK PLAN <br /> Technical Rationale for Proposed Scope of'Mork <br /> • TPHg was detected in the grab groundwater sample collected from boring SB-1 at a <br /> concentration of 780 ppb. Benzene and MTBE were not detected in this grab <br /> groundwater sample. <br /> 0 The lateral extent of petroleum hydrocarb ns in groundwater beneath the site has not <br /> been delineated. - <br /> • Depth to first groundwater beneath this site was estimated based on pore-pressure <br /> dissipation tests performed during the prev ous investigation. These tests estimated the <br /> depth to groundwater as 36.5 to 44 feet below grade (fbg). Information from the <br /> SJCPHS/EHD regarding depth to water at hearby sites suggests groundwater may be 20 <br /> to 30 fbg. <br /> SJCPHS/EHD has informed us that the reg oval groundwater flow direction the vicinity <br /> of this site is toward the southeast. <br /> 1511 2 <br /> Z <br />