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Subtask 1 Prefield Activities The following prefield activities are recommended: • Updating the site specific health and safety plan per OSHA requirements. • Obtaining the necessary permits for drilling(i.e.,PHS drilling and well permits). • Reviewing the utility lines in the area to verify safe drilling locations. Subtask 2 Field Activities Prior to conducting soil and groundwater investigation activities,the soil in the pump- island area will be regraded to minimize surface water ponding and improve conditions for monitoring well completions in this area. Under this subtask,three borings will be drilled and sampled and two of these borings will be converted to monitoring wells. Boring SB97-1 will be located at the north end of the former pump island. Borings SB97-2 (MW-11) and SB97-3 (MW-11D)will be placed near the southeast corner of the former pump island near known high concentrations of the j constituents of concern Fi ure 1). Borings SB97-1 and SB97-2 will be advanced to a depth AO, / of approximat y�eet be the groundwater table. Each of these borings will be continuously to and samples will be collected for chemical analyses. Based on the field jJPscreening and analytical results,the boring with the highest level of contamination will be i� .,ll� F ' converted into a shallow monitoring well(MW-11). After the installation of MW-11,a deep fin• DG boring(SB97-3)will be drilled in the vicinity of MW-11 to evaluate the vertical extent of soil and groundwater contamination. After the'total depth of groundwater contamination has been determined,boring SB97-3 will be converted into ep monitonng 11 (MW-11D). INv / Each boring will be: r' ,2s� • cored continuously to its intended total depth, V • screened with a photoionization detector (PID), i • sampled and field tested for Total Petroleum Hydrocarbons (TPH) as gasoline using a field test kit such as Petroflag, and • sampled and analyzed by a state-certified laboratory for analysis of TPH as gasoline and p6p benzene,toluene, ethyl benzene, and xylenes (BTEX). Al Soil samples from distinct lithological units in the deep boring will be collected and - submitted to a geotechnical laboratory for the analysis of falling head permeability using ASTM method 5084, dry bulk density using ASA 930.2,moisture content ASTM D2216,and total organic carbon using ASTM D2974. Approximately 3 to 4 soil samples per boring will be submitted to the certified laboratory for testing (Table 1). The testing will be performed to verify the field results and help calibrate the field screening techniques. As discussed above, one shallow (MW-11) and one deep (MW-11D) monitoring well will be installed in the borings that contain the highest levels on petroleum contamination. The exact location and screen interval of these monitoring wells will be determined with concurrence from PHS. 3