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t+ A S S O C I ATE S I N C . <br /> 2_3 Groundwater Sampling <br /> One groundwater sample was collected from each boring at the depth groundwater was first <br /> encountered, between 17.8 and 22 feet bgs. A Geoprobe® Screen Point 15 Groundwater <br /> ='- Sampler was threaded onto the leading end of the Geoprobe after groundwater had been <br /> encountered. When the sampler was advanced, O-ring seals and an expendable drive point <br /> F provided a watertight system to ensure sample integrity. <br /> F When the tool was advanced to the desired depth, extension rods were sent downhole to brace € <br /> the bottom of the sample screen as the tool casing was retracted. When the casing was retracted, <br /> approximately 41-inches of screen with slot sizes of 0.004 inches was exposed. Teflon tubing <br /> E : with a check valve attached to one end was inserted down the casing until it was immersed in € <br /> groundwater. Water was then pumped through the tubing and to the ground surface by <br /> oscillating the tubing up and down. Groundwater samples were placed on ice and delivered under <br /> : 3 chain-of-custody documentation to State-certified Argon Laboratories Inc. for chemical analysis. <br /> Following soil and groundwater sample collection, the borings were backfilled with neat cement <br /> F` - grout to the ground surface. <br /> 2_4 Soil and Groundwater Sample Analysis <br /> Eight selected soil samples and all groundwater samples were analyzed by Argon for TPHd by <br /> {= EPA Method 8015M. The analytical results for soil samples are summarized in Table 1 and the <br /> analytical results for groundwater samples are summarized in Table 3. Laboratory data sheets and <br /> chain-of-custody documentation are included in Appendix B. <br /> 3.0 SUBSURFACE CONDITIONS <br /> Soils encountered beneath the site consist primarily of clay, silt and sand to a depth of <br /> approximately 30 feet below grade, the maximum depth explored. From the surface to <br /> L. approximately 3 to 14 feet bgs, soil consisted of gravel and fill material. From 3 to 14 feet bgs to k <br /> 20 to 26 feet bgs, soil consisted of silt and clays. From 20 to 26 feet bgs to 30 feet bgs, the <br /> f <br /> E' maximum depth explored, soil consisted of poorly graded sand. <br /> Groundwater beneath the site was encountered at depths ranging from 17.8 to 22 feet bgs. Based <br /> on historical groundwater monitoring data collected at the site, groundwater flows to the north. <br /> w:114981114981Vvporls*i.doc 4 { <br /> rf', <br />