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Tracer Research Corporation <br /> 2.0 SITE DESCREMON <br /> ' The investigation was conducted in two areas of the site Sample WS-1-12 5' <br /> 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 /> had been removed The remaining samples were collected around various buildings in <br /> the two survey areas <br /> jSamples 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 /> ' <br /> 30 SOIL GAS SAMPLING PROCEDURES <br /> 1Soil gas sampling probes consisted of 14-foot lengths of 3/4-inch diameter <br /> hollow steel pipe The probes were fitted with detachable drive tips 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 /> (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 /> syringe by inserting a syringe 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 location. 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 314-inch diameter hollow steel <br /> pipe Groundwater samples were collected at 11 to 17 feet bgs The hollow probes <br /> with detachable drive points were advanced below the water table Once at the <br /> July 19,1994 Page 3 11402915 <br />