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KLEINFELDER 4 ACTIVITIES CONDUCTED 4.1. PERMITTING AND PRE-FIELD ACTIVITIES The San Joaquin County Public Health Services Department/Environmental Health Division (EHD) requires completion of boring permit and payment of fees prior to advancing exploratory borings. Kleinfelder prepared the drilling permit application and submitted it to EHD along with the required fees. A copy of the permit to drill is attached in Appendix E. The proposed well boring location areas were marked in white paint by Kleinfelder and Underground Services Alert was notified at least 48 hours prior to drilling activities. i 4.2 DEEP BORING AND MONITORING WELL SAMPLING/INSTALLATION Three deep borings and four well borings were advanced at the site between October 22 and October 30, 2003. The three deep well borings (1313-1, DB-2 and DB-3) were advanced in the vicinity of former underground storage tanks (USTs) at the subject site (Appendix A, Plate 4). The four well borings (MW-1 through MW-4) were advanced along the northern, eastern, and southern F property boundaries and near the former UST area (see Plate 3). The soil borings were advanced using a truck-mounted drill rig equipped with 8-inch diameter hollow stem augers. Soil samples were collected at 5-foot intervals beginning at 5 feet for logging purposes and potential chemical analysis from each of these seven borings as described in Appendix B, Section 2.3. The deep soil borings were advanced to approximate total depths ranging from 30 to 50 feet bgs. The well borings were advanced to total depths ranging from 65 to 71 feet bgs. No petroleum-like odors or soil discoloration were noted during the installation, logging and soil sample collection while advancing two of three deep soil boring and four well borings. Discolored soil with a petroleum-like odor was I noted in soil at approximate depths of 25 to 45 feet in deep boring DB-2 (eastern portion of southern UST excavation). Groundwater was not encountered in the deep soil borings DB-1, DB-2 or DB-3. Groundwater was encountered initially in the four well borings at depths ranging from approximately 56 to 66 feet bgs. i The borings were drilled, logged, and sampled according to the protocol described in Appendix B. Two-inch diameter monitoring wells were constructed in each of the four well borings (MW-1 through MW-4), as generally described in Appendix B, Section B-3.1. The monitoring wells were screened at approximate depths ranging from approximately 44 to 64 feet bgs. The wells were constructed using Schedule 40 PVC pipe with 0.020-inch factory cut slots. Copies of the boring logs and well construction details are illustrated in Appendix A A single soil sample was collected and analyzed from each of the well borings (MW 1 through MW-4) at depths just above first estimated groundwater at depths ranging from 46 to 56 feet bgs. A total of seven soil samples were collected and analyzed from the deep soil borings, two each 36274/ST03RI919 Page 6 of 19 2004 Kleinfelder, Inc. January 6,2004 i