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UST Removal Report and Request for Clontre 2 The Southland Corporation,Stone#17647,1048 Yos=te Ave,Manteca,CA January 12,1999 3.2 Sod Sample Collection On December 4, 1998, IT personnel collected one sod sample from beneath each end of each UST ' (for a total of sic)from the base of the UST excavation at depths of 14 feet below grade Two tank pit sidewall samples were also collected from depths of 6 feet below grade (Figure 2) Six sod samples were also collected from sod stockpiled during UST removal All sod sampling was conducted at the direction of Mr Harlin Knoll of the SJCPHS Additional sod stockpile sampling was conducted on December 15, 1998 Sod samples were collected in 2-inch-diameter by 6-inch-long brass tubes directly from a backhoe bucket(n the case of the stockpiles,samples were obtained about one foot below the sod surface) Sod sample tubes were sealed with Teflon pads, plastic caps and tape, labeled,placed on ice in an insulated container, and submitted for analyses under chain-of-custody manifest to a state-certified ' laboratory for analysis All soil samples collected on December 4, 1998 were analyzed for benzene,toluene, ethylbenzene, total xylenes(BTEX), methyl-terbary butyl ether(MTBE), and total petroleum hydrocarbons as gasoline ' (TPH-g) by EPA Methods 8020/8015 modified,and for MTBE and other oxygenates by EPA Method 8260 Total lead was analyzed for using EPA method 6010. Samples collected on December 15, 1998,were analyzed for BTEX, MTBE, and TPH-g by EPA Methods 8020/8015 modified 4.0 RESULTS 4.1 Geology and Hydrogeology Materials encountered during UST removal consisted largely of silty clay to depths of about 14 feet below grade Groundwater was reportedly not encountered in the UST pit during field activities, however,the SJCPHS reports that depth to water in the immediate site vicinity is about 15 feet below grade ' 4.2 Results of Soil Sample Analysis Table 1 summarizes the laboratory analytical results for sod samples collected on December 4 and 15, 1998 Benzene was not detected in any of the sod samples. Soil TPH-g concentrations in the UST pit ranged up to 1,300 milligrams per kilogram (mglkg),with concentrations in excess of 5 mg/kg being confined to the eastern part of the UST pd The UST pit sidewall samples contained no detectable hydrocarbon concentrations , Sod MTBE concentrations were less than 0 02 mg/kg in samples collected from the UST pit Soil lead levels ranged up to 6 1 mg/kg Copies of the analytical results and chain-of-custody documents are included in Appendix B 4.3 SOIL STOCKPILE SAMPLING AND ANALYTICAL RESULTS Soil samples were collected on December 4, 1998, from approximately 150 cubic yards of UST pit overburden Additional soil samples were obtained on December 15,,1998, from approximately 300 cubic yards of soil excavated dunng construction,of the new UST pit Analytical results are summarized in Table 1, and copies of the analytical data are included in Appendix B I t r I I 176471;ftW6W) I € 1 il' I r i !I I I it I' r r li r I'