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work will be conducted by an analytical laboratory certified I y the State of California to conduct { the required analyses. .I 2.2 Soil Borings At the Tank 1 and 2 location, two soil borings will be installed in positions straddling the former remedial excavation area as shown on Figure 2. Each boring will be drilled to a maximum } depth of 60 feet or the current groundwater level. Soil samples will be collected at 5-foot intervals from each boring starting at 10 bgs. All samples will be screened using a photoionization detector (PID) or flame ionization detector,(FID) and.<. ::; p :_ rc ......... :........:.....:.... r bgrtg�t 14 endfl feet bgs aang with thepr3aryge sarnpt will be submitted for chemical analyses at WESTOWs Analytical laboratory in 'Stockton, California. Additional ' sampling procedural details are provided in Section 3.2.1. At the completion of the soil { sampling, each boring will be grouted from the bottom to the surface through the augers. All soil samples will be analyzed for TPH-D and BTEX. At Tank 3 and Tank 4 locations, one boring will be placed adjacent to where the extractable hydrocarbons were originally identified. Soil samples will be taken at approximately 8 and 16 feet below grade and analyzed for both TPH-G and TPH-U. Both analyses appear prudent as ' only gasoline fuels were stored in the tanks but former analyses taken at the time of the tank ` removal suggested the presence of diesel type componentsin the soils T Bosomal fpr 1rthi galreefeddrtronal sample; writed, fihose samples Al...... ........ .........�F�� a�aal� � � The boring will be extended to the saturation zone and a ane-time sample of groundwater will be taken with a Hydropunch tool. The samples obtained will be analyzed for BTEX, TPH-G and TPH-D. While there is no history of the presence of BTEX chemicals in the soils at Tank 3 i and Tank 4, the parameter is included to tie into the investigation'work being completed at the Tank I and 2 location. l 2.3 Monitor Well Location and Installation Three monitor wells will be installed in the locations shown on Figure 2. The locations of these } monitor wells are based on a groundwater flow direction interpreted from the SJCFCD map, } "Lines of Equal Elevation of Water in Wells, Spring 1993." One well is located upgradient and i two wells are located downgradient of the excavation area. i The monitor wells will be constructed by hollow stem auger drilling techniques with a 2-inch diameter PVC casing and a 20 foot screened section. It is estimated that the total depth of each ' well will be a maximum of 65 to 70 feet. The screen will be located to set the top of screen at least 3 feet above the saturated zone. A sand pack will bei emplaced throughout the screened interval and will extend at least 2 feet above the top of the screen. A bentonite seal will be placed above the sand and the annular space will be grouted!above the seal to the surface with F a five percent bentonite/cement grout. Each monitor well will be completed in a flush mount christie box equipped with a locking cap. After construction, each well will be developed by is bailing, surging, and swabbing until the water is relatively free of sediments. The well head top k 5 ; srKviPrstislcMvco.wPz oa,oar�a I ' 1