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Samples should be kept cold (4 °C } at the <br /> laboratory until they are analyzed. Holding time <br /> ' should not exceed 14 days from the time of <br /> collection. If necessary, cold soil cores should <br /> be removed from the cylinders by spot heating the <br /> cylinder and immediately extruding the sample (or <br /> a portion of it) . A portion of the cold sample <br /> should be removed and prepared for analysis <br /> \ according to approved EPA methods. <br /> In situations where the above procedure is <br /> inappropriate, i.e. semi-solid samples, glass <br />' vials (properly prepared by contract laboratory or <br /> consultant) with Teflon seal and screw cap should <br /> be used, and maintained at 4 "C until analysis. <br />' b. Organic lead: Tetraethyl/tetramethyllead are <br /> volatile: therefore, soil samples should be <br /> collected in cylinders and kept cold as described <br /> for volatile hydrocarbons above <br /> C. Shipping Samples: Where commercial shippers are <br /> involved, dry ice may present Department of <br /> Transportation (DOT) shipping problems and "blue <br /> ice" may have to be substituted. <br /> 3 . Water Samples <br /> a. Free floating product (from a well) : Sampling of <br /> free floating product on the surface of ground <br />' water should not be performed until the well has <br /> been allowed to stabilize for at least 24 hours <br /> after development or other withdrawal procedure. <br />' A sample should be collected that is indicative of <br /> the thickness of floating product within the <br /> monitoring well. This may be accomplished by the <br /> use of a clear, acrylic bailer designed to collect <br />' a liquid sample where free product and ground <br /> water meet. A graduated scale on the bailer is <br /> helpful for determining the thickness of free <br />' product. Samples should be field-inspected for <br /> the presence of odor and/or sheen in addition to <br /> the above evaluation. <br /> Electronic measuring devices also are available <br /> for determining the thickness of the hydrocarbon <br /> layer floating on ground water. <br /> b. Dissolved product (from a well) : If free product <br /> is detected, analysis of water for dissolved <br /> product should be conducted after the free product <br /> A13 <br /> 1 <br />