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Work Plan 1� Frontier Transportation Page 3 water has been encountered between 6' and 10' bg. The groundwater flows generally in a western : direction beneath the site. 4.0) PROPOSED SCOPE OF WORK BEII proposes to install an additional groundwater monitoring well (MW- 14) to delineate the lateral extent of dissolved petroleum hydrocarbons (See Figure 2 for Proposed Well Location) . A hollow stem auger rig will be used to provide the soil borings for well installation. _ Drillers will hold a California State C-57 contractor's license. The well will basically consist of a central section composed of riser and - screen. The annular space around the screen will be filled with sand from 40 ' bg to 27 ' bg. This will be overlain with a 7-foot seal of bentonite pellets, then grouted to near ground surface with a 5% bentonite mixture with cement and water. The bentonite and annular seals are necessary to prevent the annulus from serving as a vertical conduit for potential contaminants. A lockable flush-mount protective casing will be set over the well top and surrounded by a surface seal of concrete. The riser and screen will be constructed of two-inch inside diameter, schedule 40 polyvinyl chloride (PVC) pipe. Slotted PVC will extend from approximately 40 ' bg to 30 ' bg and it will contain three rows of 0.010-inch slots. Ends of the screen and riser sections will be constructed with flush joining threaded fittings to ensure leak-proof unions. A filter pack of sand will be placed around the screen to retain the finer grained fractions of formation material and to create a zone of high permeability that allows free entry of water in the well. The pack will consist of clean quartz sand (#2/16). Following placement of the annular seal, a large-diameter flush-mount protective casing will be installed around the well head. The casing will be firmly seated in concrete and supplied with lockable covers for security (See -I Figure 3 , Well Completion Diagram). 4.1) Soil Sampling I� Soil samples will be collected at least at 5 ' intervals in each boring and at depths where visual or photoionization (PID) inspection indicates contamination. All samples will be collected in a split spoon sampler lined with 2-inch by 6-inch long brass . The sample will be immediately sealed with Teflon tape, capped, and packaged using a PID to detect volatile organic compounds. Only those soil samples which detect petroleum hydrocarbon vapors using a PID or ( i visual inspection will be analyzed for TPH-g, BTEX, and MTBE at a California certified toxics analysis laboratory using EPA methods 8015 modified, 8020, and 8260 . 4.2) Analytical Methods and Quality Assurance A California Department of Health Services certified laboratory would conduct all 3 (: I