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Geosyntec o <br /> consultants <br /> Samples will be selected to represent each distinct--geologic layer. The number of samples to be <br /> collected will be_determined by.the.geologist after, inspection of the soil core and consideration <br /> of the degree of heterogeneity in the geologic materials. <br /> 2.5 Soil Gas Probe Installation <br /> Each soil gas probe will consist of./-inch diameter Nylaflow® or Teflon® tubing connected <br /> with a compression fitting to a %-inch-diameter:stainless steel sampling-point. Probes will be <br /> installed inside the borehole-and a sand filter:pack will be placed in the`annulus to a height of 6 <br /> inches above the top of the screen. .'Granular bentonite will.be placed in,two lifts of 3 inches <br /> above the filter pack and hydrated;with-a small amount of distilled water after each lift. A thick <br /> slurry of powdered bentonite and water- will be added loseal.seal.the remainder of.the borehole <br /> annulus to ground surface. The top of the probe will be. fitted witha compression-fit brass or <br /> stainless steel ball valve .to s,maintain an air-tight seal between` installation and sampling. <br /> Permanent probes will be completed with a traffic ratedflush mount.protective casing. <br /> 3 "DOCUMENTATION <br /> Field documentation will include the following information: <br /> • name and number of project; <br /> • name of field personnel; <br /> • date and time of sampling event; <br /> • list of the primary activities performed; <br /> • identification of probes drilled and installed; <br /> all related information (weather; attendees, equipment problems, any departures <br /> from standard.procedures and the reasons and.responses) observed throughout the <br /> day; <br /> •. field instrument information and calibration data.(includes time and reading for <br /> each instrument calibration.check; and <br /> • volume of probe dead space volume for each-soil gas probe. <br /> 2 2009.12.03 <br />