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Tracer Research Corporation <br /> T <br /> 2.4 STTE DESCRHMON <br /> The investigation was conducted 1n two areas of the site Sample WS <br /> f was collected next to a tank pit The underground storage tank (UST) was previously <br /> removed Sample SG-2-12.5' was collected next to a dike area where a second UST <br /> l <br /> - had been removed.' The remaining samples were collected around various buildings in <br /> the two survey areas <br /> Samples were collected through gravel cover The subsurface of the site was <br /> reported to consist of sand, gravel and clay with sand lens. The depth to groundwater <br /> was reported to be 8 5 feet bgs and the direction of groundwater flow was reported to <br /> be northeast <br /> 30 SOIL GAS SAMPLING PROCEDURES <br /> Soil gas sampling probes consisted of 14-foot lengths of 314-inch diameter <br /> hollow steel pipe The probes were fitted with detachable drive tsps and hydraulically <br /> pushed and/or pounded to a depth of 12 to 14 feet bgs <br /> The aboveground end of each probe was fitted with an aluminum reducer <br /> I_ (manifold) and a length of polyethylene tubing leading to a vacuum pump Soil gas <br /> was pulled by the vacuum pump into the probe Samples were collected in a glass <br /> lsyringe by inserting a synnge needle through a silicone rubber segment in the <br /> evacuation line and down into the steel probe The vacuum was monitored by a <br /> vacuum gauge to ensure an adequate gas flow from the vadose zone was maintained <br /> The volume of air within the probe was purged by evacuating 2 to 5 probe <br /> volumes of gas The evacuation time in minutes versus the vacuum in inches of <br /> mercury (Hg) was used to calculate the necessary evacuation time. The vacuum in <br /> inches Hg was recorded at each sampling Iocation. Probe vacuums ranged from 5 to <br /> 19 inches Hg. The maximum capacity of the pump was approximately 22 inches Hg <br /> 4.0 GROUNDWATER SAMPLING PROCEDURES <br /> When groundwater was encountered, water samples were collected. <br /> Sampling probes consisted of 14- to 21-foot lengths of 3/4-inch diameter hollow steel <br /> pipe. Groundwater samples were collected at 11 to 17 feet bgs The hollow probes <br /> with detachable dnve points were advanced below the water table Once at the <br /> l <br /> July 19.IM Page 3 114M91S <br /> n <br />