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7�IVIA • y .• A 5 S O C I A T E 5 I N C+. Installation of Soil Borinrrs To further assess the extent of impacted soil and groundwater at the site, a total of five soil borings will be advanced at the site. To address lateral definition, four perimeter borings will be advanced to first encountered groundwater, estimated at approximately 12 feet bgs. A fifth soil boring will be advanced through the tank pit beyond the water table to a total depth of approximately 35 feet bgs to assess the vertical extent of petroleum hydrocarbon contamination. Proposed boring locations are shown on Figure 3. The five borings will be advanced using truck mounted Geoprobe® narrow diameter, direct push technology. Drilling will be conducted by a State-licensed (C57) drilling company. A field geologist will be present to log all soil samples. Descriptions of soil types encountered and sample collection intervals will be recorded on boring logs. Soil samples will be collected at five- foot intervals, field screened with a Flame Ionization Detection(FID)meter, and an estimated two soil samples from each of the borings will be submitted for laboratory analysis. Soil sample selection will be based on FID measurements and field observations (i.e. odor and soil discoloration). One groundwater sample will be collected from each of the borings at the desired completion depth, anticipated to be approximately 12 feet bgs for the perimeter borings and 35 feet for the deeper boring. A Geoprobe® Screen Point 15 Groundwater Sampler will be threaded onto the leading end of the Geoprobe when the groundwater is encountered. While the sampler is advanced, O-ring seals and an expendable drive point will provide a watertight system to ensure sample integrity. When the tool has been advanced to the desired depth, extension rods will be sent downhole to brace the bottom of the sample screen as the tool casing is retracted. When the casing is retracted, up to 41-inches of screen with slot sizes of 0.004 inches will be exposed. Teflon tubing with a check valve attached to one end will be inserted down the casing until it is immersed in groundwater. Water will then be pumped through the tubing and to the ground surface by oscillating the tubing up and down. Following soil and groundwater sample collection, the borings will be backfilled with neat cement grout to the ground surface. All drill cuttings, if any, will be stored on-site in a 5-gallon container pending laboratory results. wA17292.0002Nropoits\wkp.dm 3