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Excavation Confirmation Sampling <br /> A California-certified laboratory will analyze soil samples to confirm that <br /> TPH-impacted soils have been adequately excavated These confirmation <br /> samples will be analyzed for TPH (gasoline and/or diesel, as appropriate) <br /> by United States Environmental Protection Agency (USEPA) Method <br /> 8015-Modified, and for BTEX by USEPA Method 8020 Because the <br /> monitoring data have not shown EDB or lead above levels of concern, <br /> analysis for these compounds will not be performed <br /> The confirmation sampling program will consist of collecting a total of <br /> --�� five four-point composite samples from 1) the base of the excavation and <br /> 2) each excavation wall Samples will be collected either by directly <br /> driving a pre-cleaned brass tube six inches deep into the soil, or by <br />' collecting a sample from the backhoe bucket For samples collected from <br /> the backhoe bucket, the backhoe will collect a full bucket from the <br />' appropriate sampling location A pre-cleaned brass tube will then be <br /> pushed into the mass of soil in the backhoe bucket until the tube is filled <br /> Tubes will be sealed by placing TeflonO film over the ends and securing it <br />' 1n place with plastic caps Each tube will be labeled with a unique sample <br /> number The tubes will then be placed in a ZxplocO-type plastic bag, <br /> sealed, and placed on ice in a cooler until they are analyzed <br /> Excavation Backfillin <br /> The excavations will be backfilled as soon as possible after the <br /> confirmation sampling and analysis have been completed As noted <br /> earlier, any soils that are excavated and found by testing to contain <br /> TPH/BTEX concentrations below the action levels will be stockpiled for <br /> reuse as backfill The remaining area of the excavations will be backfilled <br />' with clean, certified backfill Where necessary, geo-textile/rock <br /> stabilization will be utilized <br />' The excavations will be backfilled 1n 6- to 8-inch lifts, and compacted with <br /> a small steam roller 1 The soil will be compacted to 90 percent to prevent <br /> excessive settling The soil compaction will be verified with a nuclear <br /> density gauge during the backfilling operations <br /> 1 <br /> 1 <br /> Because of the small area of the proposed excavations,conventional equipment would be too <br />' large <br /> 5-3 <br />