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gp <br /> " ffig <br /> K <br /> r <br /> Field Procedures <br /> Soil gas samples were collected at a total of 24 locations at <br /> the site, as shorn in Figure 1. To collect the samples a 1/2 inch <br /> hale was produced to a depth of approximately four feet by using <br /> a drive rod. Where pavement was present, an electric hammer drill <br /> was employed far penetration prior to using the drive rod. The <br /> entire sampling system was purged with ambient air drawn through <br /> a dust and organic vapor filter cartridge, and a stainless steel <br /> he full depth of the hole and sealed <br /> probe was inserted to toff <br /> !" sample of ill--situ soil gas was then with- <br /> from the atmosphere. A <br /> and used to purge ambient air from the,,. <br /> drawn through the probe <br /> �. sampling system. A second sa:aple of soil gas was withdrawn through <br /> the probe and encapsulated in a pre-evacuated glass vial at two <br /> atmospheres of pressure (15 prig) . The self-sealing vial was <br /> �- tem, packaged, labeled, and stored <br /> detached from the sampling sys <br /> �E for laboratory analysis. <br /> Prior to the day's field activities all sampling equipment, <br /> drive rods, and probes were decontaminated by washing with soapy <br /> distilled water: and rinsing with distilled water. Internal sur- <br /> - faces were flushed dry using pre-purified nitrogen, and external <br /> surfaces were wiped clean using clean paper towels. <br /> Field control samples were co1jected at the beginning and t, <br /> end of the day's field activities. These QA/Qc samples were <br /> 20 psi <br /> obtained by inserting the probe tip into a tube flushed by a <br /> flow of pre-purified nitrogen and collecting in the same manner as <br /> described above. <br /> ti, <br />