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Phase II Environmental Site Assessment Investigation Report 206 Sutter Street, Stockton, California Page 2 3.0 SAMPLING PROCEDURES AND RATIONALE 3.1 SITE PREPARATION Condor obtained the necessary drilling permits from the San Joaquin County Environmental Health Department (SJCEHD) prior to scheduling field activities with the sub-contractors and notifying Underground Services Alert (USA). The proposed boring locations were marked with white paint and Underground Service Alert (USA) was notified over 48 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. In addition, a private utility locator was contracted to scan and identify potential subsurface piping and other anomalies within a five-foot radius of each boring location a ground penetrating radar (GPR). Prior to initiating fieldwork at the Site, a tailgate safety meeting was held prior to commencement of fieldwork on location and all field personnel reviewed and signed the site-specific health and safety plan included in the approved Work Plan. 3.2 DIRECT PUSH BORING PROCEDURES Luke Castle (CA Professional Geologist number 9945) observed drilling and collected samples at the Site on September 22, 2022 and September 23, 2022. Confluence Technical Services, Inc. (Confluence), a California licensed drilling contractor (C57-1035255), conducted all drilling under Permit #WP0043652 issued by SJCEHD. Appendix B includes a copy of the drilling permit. Condor conducted the sampling in general accordance with the Phase II Environmental Site Assessment Investigation Work Plan, APN 139-250-030, 206 N. Sutter Street, Stockton, San Joaquin County, California, dated August 4, 2022, prepared by Condor (Work Plan). DP-1 soil boring was advanced to 60 feet bgs, DP-3 and DP-6 soil borings were advanced to 35 feet bgs, and DP-4 and DP-7 soil borings were advanced to 45 feet bgs. DP-2 and DP-5 soil borings were not advanced during this investigation due to logistical and time constraints. A boring location map is included on Figure 3, Appendix A. Samples were collected every 5 feet, and drill rods were decontaminated by steam-cleaning. A photoionization detector (PID) was used to screen soil samples for VOCs. Groundwater samples were collected from all five (5) of the completed borings. The direct push borings were advanced using a Geoprobe 6600 direct push drilling rig equipped with a 2.25-inch-diameter conical bit, which was driven using a hydraulic hammer. Upon completion of the borings and sampling, all borings were grouted to the ground surface with neat cement grout. The soil samples were logged in general accordance with the Unified Soil Classification System (USCS). Geological logs were prepared containing field observations including soil type, PID measurements, and the presence of staining or odor (Appendix C). Portions of the soil samples were placed in polyethylene bags and checked with a PID for the presence of VOCs. Soil samples were collected from the borings for laboratory analyses based on field observations and PID measurements. The soil cuttings were placed in a 5-gallon buckets and Zip-lock bags, sealed, labeled, and taken back to Condor’s storage warehouse pending results of laboratory analyses. Each soil sample collected for possible laboratory analyses was cut from the acetate liners. The liners were sealed at the ends with Teflon sheeting and capped. Groundwater samples were collected using dedicated tubing with a foot valve. Groundwater and soil samples were labeled, placed in chilled coolers, and transported under chain-of-custody procedures to McCampbell Analytical Incorporated (CA ELAP #1644).