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' Site Background Information Terminous Market Page 3 of 3 • BTEX and fuel additives MTBE, di-isopropyl ether (DIPE), ethyl tertiary-butyl ether ' (ETBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB)by EPA Method 8260B ' TPH-g was detected in the soil sample collected from boring MW3 at 10 feet and 15 feet bsg (MW3-10 and MW3-15,respectively) at concentrations of 5 2 mg/kg and 1 5 mg/kg, respectively BTEX compounds were detected in samples MW3-10 and MW3-15 at maximum concentrations in ' MW3-10 of 0 064 mg/kg toluene,0 13 mg/kg ethylbenzene,and 0 64 mg/kg total xylenes Analytical results of soil samples are summarized in Table 2 of this appendix ' Pilot borings MW 1 through MW4 were completed as ground water monitoring wells MW-1 through MW-4 using 2-inch diameter polyvinylchloride (PVC) casing with a 0 020-mch slotted screen installed from 5 feet to 25 feet bsg The filter pack(No 3 Lonestar sand)was installed from 4 feet to 25 feet bsg, and a nominal 2-foot bentonite chip plug was installed above the filter pack and hydrated The remaining annular space was filled to near the surface with neat cement and water- tight, traffic-rated well boxes were installed over the wells On 03 November 2004,monitoring wells MW-1 through MW-4 were developed utilizing a Waterra inertia pump and steel bailer, and on 24 November 2004, a California state-licensed surveying engineer from Morrow Surveying surveyed the location and elevation of monitoring wells MW-1 through MW-4 The vertical extent ofpetroleum hydrocarbon-impacted soil is defined in boring MW3,hydrocarbon contamination was not detected in samples collected below 15 feet bsg The lateral extent of petroleum hydrocarbon contamination is defined in the east by monitoring well MW-4 and in the southwest by wells MW-I and MW-2 The lateral extent of contamination is not yet defined to the north, south, or southeast of well MW-3 STRATIGRAPHY In general, moist, black peat and silty peat were encountered in borings MW 1 and MW2 from surface grade to approximately 5 feet bsg in boring MW 1,and from surface grade to approximately 9 5 feet bsg in boring MW2 Some hydrocarbon staining occurred in the peat in boring MW2 Black fill dirt was encountered in boring MW3 from surface grade to approximately 5 feet bsg,and moist to saturated,blue gray, silty clay, sandy clay, and clayey silt was encountered in boring MW4 from surface grade to approximately 15 feet bsg,underlain by very moist to saturated,gray brown to blue gray silty sand and sandy silt that extended to total depth From 10 feet bsg to the total depths of borings MW 1 through MW3, interbedded layers of moist to saturated, orange brown, brown, and green brown sandy silt, silty sand, silty clay, clayey silt, and clay were encountered Advanced GeoEnvironmental,Inc