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Phase II Environmental Site Assessment Report Buena Vista Storm Drain,Stockton,CA March 30,2005 Page 2 3.0 DIRECT PUSH BORING FIELD PROCEDURES This section includes a description of Site preparation activities and direct push boring procedures. 3.1 SITE PREPARATION A drilling permit application was prepared by Condor and submitted to the SJCEHD for twelve proposed direct push borings. An encroachment permit application was also prepared and submitted to the City of Stockton for the borings. Condor received the SJCEHD drilling permit and the City of Stockton encroachment permit prior to initiating any fieldwork. The proposed boring locations were marked with white paint and Underground Service Alert (USA) was notified 48 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. 3.2 DIRECT PUSH BORING PROCEDURES A Condor geologist was on site to supervise the work. Prior to commencement of fieldwork, a tailgate safety meeting was held and a site-specific Health and Safety Plan was discussed with, and presented to, all field personnel for their signatures. The investigation included the advancement of twelve direct push borings (GP-1, GP-2, GP-3, GP4, GP- 5, GP-6, GP-7, GP-8, GP-9, GP-10, GP-11, and GP-12) to collect groundwater samples on March 15, 2005. The boring locations are shown in Figure 2,Appendix A. 3.2.1 Groundwater Sampling The direct push borings were hydraulically advanced using a two-inch outside diameter conical bit. The bit and associated push rods were thoroughly cleaned before each borehole was advanced using laboratory-grade, non-phosphate detergent and deionized water and double-rinsed with deionized water. A temporary '/<-inch outside diameter PVC screen was placed into each boring for the collection of groundwater samples. Groundwater flowed hydrostatically from the formation into the temporary PVC screen. Borings GP-1 through GP4, GP-6 through GP-10, and GP-12 were advanced to 20 feet below ground surface (bgs). Borings GP-5 and GP-11 were advanced to 25 feet bgs. Borings GP-2 and GP-3 collapsed to approximately 15 feet bgs while inserting the temporary PVC screen. One groundwater sample was collected from each of the borings after all 12 of the borings were advanced. Upon completion of the boring and sampling, the boreholes were backfilled with a grout consisting of neat cement. The grout was tremied into the boreholes. A groundwater sample was retrieved from within each temporary PVC screen with a length of clean, 3/8- inch diameter polytygon tubing equipped with a check valve at the bottom.The tubing was moved up and down by hand to draw groundwater up inside the tubing. The groundwater sample was discharged directly from the tubing into laboratory supplied sample containers. The sample containers were sealed, labeled, placed in a cooler chilled with ice, and delivered under chain-of-custody procedures to Argon Laboratories in Ceres, California, for analyses. The samples were analyzed using U.S. EPA Methods and California-approved methods. 4M 1�k �a CONDOR