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i <br /> Id <br /> t <br /> 4.3 EXISTING OIL PIPING AND UST EXCAVATIONS <br /> Hydrocarbons were detected as TPH-diesel at a concentration of 29 mg/kg in one <br /> ' f in-situ sample from the motor and used oil UST excavation. This _ample was <br /> �.. located along the eastern side of the excavation beneath Tank 6 (motor oil). <br /> No other organic constituents were detected in samples from this excavation. <br /> Oil and grease were not detected in in-situ soil samples from the oil <br /> P pipe <br /> trenches. Cadmium, chromium (total), lead (total), nickel and zinc, detected <br /> in samples from benea0 the used oil UST and pipe, were all at concentrations <br /> beneath their total threshold limit concentrations (TTLCs). <br /> .5.0 STOCKPILE CHARJACTERIZATION <br /> All excavated soils and bsck,1 11 materials were segregated based upon <br /> potential hydrocarbon contamination and date of excavation (Table 3). <br /> Stockpile samples were taken at frequencies (cubic yards <br /> per composite sample) <br /> specified by San Joaquin County Public Health Services personnel, as follows: <br /> One sample per 50 cubic yards for stockpiles originating from the <br /> excavation of native materials for placement of new USTs. <br /> One sample per 25 cubic yards for stockpiles originating from the <br /> excavation of former USTs and hydrocarbon piping. <br /> A <br /> ! ' 5.1 NEW UST STOCKPILE <br /> t� _ <br /> Eight hundred (800) cubic yards of apparently uncontaminated material (Pile 1) <br /> �. were removed from a formerly-undisturbed area which contained no hydrocarbon <br /> tanks or pipes. This material was apparently uncontaminated and subsequent <br /> testing of 16 composite samples for TPH-gasoline and BTEX detected nothing <br /> (Table 4). Following testing of a single composite sample for reactivity, <br /> t • <br /> corrosivity and ignitability (RCI) (Table 8), this stockpile was disposed at <br /> the Vasco Road Class III landfill in eastern Alameda County. Chain-of-Custody <br /> and Requests for Analysis are shown in Appendix C and laborat&-y Certificates <br /> i. Of Analysis are shown in Appendix E. <br /> 5.2 FUEL PIPING AND UST STOCKPILE <br /> hundred yards (600) of apparently contaminated material (Piles 2, 5 and 7) <br /> were removed from around three fuel USTs and associated piping. Subsequent <br /> 6 . <br /> wriA:ENG:9199/04159 3 <br />