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Lo �.Cv ATC A S S O C I A T E S I N C , &„ 2.1 Drilling Activities On January 4, 2002, an ATC geologist supervised the advancement of three soil borings to L depths of 11 to 16 feet below ground surface (bgs). The initial boring, SBI, was advanced to the first encountered groundwater and terminated at 11 feet bgs. At the request of Ms. Margaret Lagorio of PHS/EHD, the two subsequent borings were advanced to 16 feet bgs. A site plan with soil boring locations is shown on Figure 2. Fisch Environmental, California License C57 683865, advanced the borings using a truck mounted GeoprobeO narrow diameter rig employing I La direct push technology. Soil samples were collected at five-foot intervals. Samples were collected in acetate sampling tubes and were described according to the Unified Soil Classification System. Descriptions of soil types encountered and sample collection intervals are presented on the boring logs contained in Appendix A. 222 Soil Sampling and Analysis i L Each soil sample was field screened with a Flame Ionization Detector (FID) for the presence of volatile organic compounds. Sample tubes were then sealed at each end using Teflon tape and LW plastic end caps, labeled, and placed on ice. Selected soil samples were kept on ice and delivered under chain-of-custody documentation to • Argon Laboratories Inc. (ELAP Cert. No. 2359) in Ceres, California for chemical analysis. Selected soil samples were analyzed by Argon for TPHg by EPA method 8015; BTEX by EPA method 8020; methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME), tertiary butyl ether (TBA), ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPS), 1,2- r dichloroethane (1,2-DCA), and ethyl dibromide (EDB) by EPA method 8260; and total lead. 223 Groundwater Sampling and Analysis r One groundwater sample was collected from each boring at the depth groundwater was first encountered, approximately 10 feet bgs. A GeoprobeO Screen Point 15 Groundwater Sampler was threaded onto the leading end of the Geoprobe after groundwater had been encountered. When the sampler was advanced, O-ring seals and an expendable drive point provided a watertight system to ensure sample integrity. �.. When the tool was advanced to the desired depth, extension rods were sent downhole to brace the bottom of the sample screen as the tool casing was retracted. When the casing was retracted, approximately 41-inches of screen with slot sizes of 0.004 inches was exposed. Teflon tubing with a check valve attached to one end was inserted down the casing until it was immersed in groundwater. Water was then pumped through the tubing and to the ground surface by oscillating the tubing up and down. Following soil and groundwater sample collection, the borings were backfilled with neat cement grout to the ground surface. I w:19205410020%sum.doc 2