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O&TC <br /> ASS O C I ATE S I N C . <br /> LW hydrocarbons as gasoline (TPHg) by EPA method 8015 modified, benzene, toluene, ethyl <br /> benzene, and xylenes (BTEX) by EPA method 8020, and oxygenate fuel additives by EPA <br /> method 8260. The analytical results for soil samples are summarized in Table 1. Laboratory <br /> data sheets and chain-of-custody documentation are included in Appendix B. <br /> 2.3 Grab Groundwater Sampling and Analysis <br /> Groundwater samples were collected from borings SBB, SB9, and SBIO at the depth <br /> groundwater was first encountered, approximately 10 feet bgs. In addition, one grab <br /> groundwater sample was collected from boring SB 10 at 30 feet bgs at the request of Mr. Jeff <br /> Wong of PHS/EHD. A Geoprobe® Screen Point 15 Groundwater Sampler was threaded onto <br /> the leading end of the Geoprobe after groundwater had been encountered. When the sampler was <br /> advanced, O-ring seals and an expendable drive point provided a watertight system to ensure <br /> sample integrity. <br /> L. <br /> When the tool was advanced to the desired depth, extension rods were sent downhole to brace the <br /> bottom of the sample screen as the tool casing was retracted. When the casing was retracted, <br /> i approximately 41-inches of screen with slot sizes of 0.004 inches was exposed. Teflon tubing <br /> with a check valve attached to one end was inserted down the casing until it was immersed in <br /> r— groundwater. Water was then pumped through the tubing and to the ground surface by <br /> oscillating the tubing up and down. Following soil and groundwater sample collection, the <br /> } <br /> borings were backfilled with neat cement grout to the ground surface. <br /> " Groundwater samples were placed on ice and delivered under chain-of-custody documentation to <br /> Argon for chemical analysis. Groundwater samples were analyzed by Argon for TPHd and <br /> TPHg by EPA Method 8015, BTEX by EPA Method 8020, and oxygenate fuel additives by EPA <br /> method 8260. The analytical results for groundwater samples are summarized in Table 2. <br /> Laboratory data sheets and chain-of-custody documentation are included in Appendix C. <br /> i. <br /> 22.4 Hollow Stern Auger Drilling Activities <br /> Drilling was conducted by V & W Drilling (State C57 Iicense no. 720904) utilizing a hollow <br /> stem auger drill rig. Soil boring SB 12 was advanced to 51.5 feet bgs to attempt to define the <br /> vertical extent of impacted soil and groundwater and was grouted to the surface after soil and <br /> �. groundwater samples had been collected. Soil borings MW4, MWS, and MW6 were advanced to <br /> attempt to define the lateral extent of impacted soil and groundwater and were completed as <br /> groundwater monitoring wells. Approximately 10 inches of free product was discovered in <br /> ;* boring MW4 at a depth of 20 feet bgs. The free product appeared to most resemble TPHd. At <br /> the request of Mr. Jeff Wong of PHS/EHD, boring MW4 was completed as a groundwater <br /> R <br /> monitoring well. The soil borings MW5 and MW6 were advanced and completed as <br /> LM - groundwater monitoring wells. A field geologist logged drill cuttings and soil samples utilizing <br /> the Unified Soil Classification System. Descriptions of soil types encountered and sample <br /> LW <br /> wA54,625001reportslsumiii.doe 3 <br /> i+ <br />