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r./ obtained from the PHS/F-HD. In addition, Underground Services Alert (USA Alert) will be contacted to identify underground public utilities, which will be marked in the field prior to commencement of field activities. The site owner will also identify any underground utilities and piping of which they may have knowledge. r Three shallow groundwater monitoring wells will be installed and sampled to characterize the lateral extent of PHCs in groundwater and to monitor the local groundwater gradient. The proposed locations of the monitoring wells, designated MW 5-1 through MW 5-3, are shown on Figure 2. Monitoring well MW 5-1 will be installed near boring B5-1, as this was the only soil boring that showed any PHCs in groundwater during the initial subsurface investigation. Monitoring well MW 5-2 will be installed near boring B5-5 (near the former dispenser), which had higher PHC concentrations than B5-4. Monitoring well MW 5-3 will be installed in the northwest corner of the site to provide a point for triangulation of the groundwater surface and to monitor groundwater beneath the pipeline that connected the former tanks and dispenser. The monitoring wells will be installed, developed, and sampled in general accordance with ASTM Standard D 5092-90,"Design and Installation of Groundwater Monitoring Wells in Aquifers," and ASTM Standard D 4448-85a, "Sampling Ground Water Monitoring Wells." 3.1.1 Pilot Borings Based on present information, it is anticipated that groundwater will be encountered at a depth of about 10 feet bgs. Unless subsurface conditions encountered et ring drilling dictate otherwise, the proposed screen interval for the wells will be from 5 to 2 g s. An 8-inch diameter(4-inch I.D. auger) pilot boring for each of the monitoring wells will be drilled logged by the field to a depth of about 25 feet bgs. Soils from the borings will be litholagically gg st using the Unified Soil Classification System. Soil cuttings g tcanst o to a designated during drilling will geologt g be temporarily stored on-site during drilling and well installation, anP on-site area after completion of the well. .. drilling, cuffings will be visually examined for evidence of PHCs- naddition,ll also be ugsed to be scrThe PID g be screened with a portable photoionization detector (PID). tan. monitor air in the breathing zone in accordance with the site health and safety p Equipment used during the drilling activities will be decontaminated before arriving on-site,between each ilot boring, and before leaving the site. Decontamination will be accomplished using the P following four step process: 5 PHILIP P. ROSS,R.G-