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( i,I(rim i'rcxlut IN( umh 111y <br /> ( ht Arun Si Itrim#9_121 2—SG6U ientcr S tcg_f[III ntkI KO d "ItX kttltr (_IIIlA'III f� (h l ONr_ <br /> moniloied (.on11nii0(151V ful 1,O)l hchaVIOT and pnre pretisuic to a11Tc;'NiitIately S7 ILCt bL low <br /> toiound tiurfa[.e (h)s) BaWd cm poic pie5sute and on lithologic, information collected tions <br /> the CPT log,,, one depth-di%LrCte gloundwatcr sample was(,ollectc.d from each of the direct- <br /> push borings Groundwater samples were analyzed for the presence total petroleum <br /> hydrocarbons quantified as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes <br /> (BTEX), and the fuel oxygenates methyl tertiary butyl ether (MtBE), di-isopropyl ether <br /> (D1PE), tertiary amyl methyl ether(TAME), ethyl tertiary butyl ether (EtBE), tertiary butyl <br /> alcohol (TBA), ethyl dibromide (EDB), and 1,2 dichloroethane (1,2-DCA) by EPA Method <br /> 8260B Upon completion, the borings were filled with grout from the bottom up and finished <br /> to surface grade with either asphalt or concrete depending on the preexisting surface material <br /> Field and laboratory procedures are presented in Attachment B The findings of this <br /> assessment are summarized below <br /> • Subsurface Conditions. Review of the CPT logs suggests clay mixtures with silt <br /> and/or silt mixtures with clay comprise most of the stratigraphy to an approximate <br /> depth of 55 feet bgs at each CPT location Multiple thin sand layers were <br /> encountered in most of the borings, however, groundwater was not observed within <br /> the sand Iayers encountered near the surface(approximately 15 feet bgs) <br /> Groundwater was expected to be encountered at approximately 33 feet bgs based on <br /> recent groundwater monitoring events, however, groundwater was observed in a sand <br /> layer at approximately 50 feet bgs at most of the boring locations. CPT logs are <br /> included as Attachment C <br /> . • Groundwater Analytical Results. Groundwater samples were submitted to a <br /> California state-certified laboratory and analyzed for the presence of TPHg, BTEX, <br /> and the fuel oxygenates MtBE,DIPE,TAME,ELBE,TBA,EDB, and 1,2-DCA One <br /> depth-discrete groundwater sample was collected from each of the bongs m the <br /> identified water-beanng zone at approximately 49 to 53 feet bgs and submitted for <br /> chemical analysis. Groundwater analytical results are presented in Table 1. <br /> Groundwater analytical data are presented graphically in Figure 2 Certified <br /> analytical reports and chain-of-custody documentation are presented as Attachment <br /> D <br /> TPHg was detected in two groundwater samples at concentrations of 0.24 micrograms <br /> per liter(gg/l)in CPT-3 and 0 056 µg/1 in CPT-6 TBA was detected in four <br /> groundwater samples at concentrations ranging from 5 4 ggfl in CPT-3 to 21 gg/1 in <br /> CPT-1 1,2-DCA was detected in four groundwater samples at concentrations <br /> ranging from 4 6 µg/1 in CPT-3 to 10µg/l in CPT-1 None of the other chemicals for <br /> which the samples were analyzed were detected above their respective method <br /> detection limits <br /> Well Search <br /> On June 4, 2001, SECOR personnel performed a water well search to identify the location of <br /> • documented water Supply wells within a one-mile radius of the site The water well search <br /> c,onm,,led of examining the files of the California DepartmCTit of Water Resouices (DWR) <br /> IV Irc�nmlt)"12% 1 N)HIM01-M( F1 SA?Uf)1 dtx <br />