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1 <br /> ' 2.3 <br /> Soil and Groundwater Sample Analyses <br /> ' Soil and groundwater samples were placed on ice and delivered under chain-of-custody <br /> documentation to State-certified Argon Laboratories in Ceres, California for chemical analysis <br /> ' Groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) <br /> utilizing EPA method 8015 modified, benzene, toluene, ethyl benzene, and xylenes (BTEX) <br /> utilizing EPA method 8020, and MTBE, ethyl tertiary butyl ether (ETBE), di-isopropyl ether <br /> ' (DIPE), tertiary butyl alcohol (TBA), tertiary amyl ether (TAME), 1,2-dichloroethane (1,2- <br /> DCA), 1,2-dibromoethane (EDB), ethanol, and methanol by EPA method 8260 "The <br /> analytical results for soil and groundwater samples are summarized in Tables 1 and 2. <br /> ' Laboratory data sheets and cham-of-custody documentation are included in Appendix C and <br /> D. <br /> 3.0 SUBSURFACE CONDITIONS <br />' 331 Geology <br /> s <br /> Soil generally consisted of inorganic clays and silty clays to a depth of 10 feet bgs (maximum <br /> explored depth) as observed from the direct push Geoprob&M soil borings The CPT to situ <br /> down-hole measuring technique allowed for a more Sginsrehensive lithologic evaluation with a <br /> maximum explored depth of 80 feet bgs 'Silts and siltylays were observed throughout the CPT <br />' boring interval with three distinctive gravel-sand units located from approximately 38 to 45 feet" <br /> bgs, 65 to 70 feet bgs,and 73 to 78 feet bgs, respectively Refer to Appendix B for the soil <br /> boring logs <br /> 3^2 Hydrogeology <br />' Water level measurements collected from monitor wells MW1 through MW8 in December <br /> 2004 had an average depth to water elevation of 5 to 7 feet below the top-of- casing Shallow <br /> groundwater flow beneath the site was towards the northeast -The average hydraulic gradient on <br />' during the December 2004 monitoring event was calculated to be 0 0022 ft/ft or approximately <br /> 116 ft/mile Refer to ATC's Fourth Quarter 2004 Monitoring Report dated February 2, 2005 <br /> This information represents the shallow water bearing unit located from approximately 18 to ? <br /> 20 feet bgs Three additional water bearing units were observed from the data collected during <br /> the CPT measurement while drilling activity These water bearing units were observed at 38 <br />' to 45 feet bgs, 65 to 70 feet bgs, and 73 to 78 feet bgs, respectively <br />' 4.0 RESULTS <br /> . 4^1 Soil Analytical Results <br /> 1 <br /> S\Enviromentafl258471Reports\SUM doe 4 <br />