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Section 2.0 UST Removal and Soil Sampling Activities • removal process and approved the tanks for offsite transport and disposal. The USTs extended to a depth of approximately 16 feet bgs and the UST tank pit which was filled with pea gravel extended beneath the USTs to a depth of approximately 17.5 feet bgs. Soil samples were collected beneath both ends and the middle of each UST at a depth of approximately 18 feet bgs, which corresponded to a depth of approximately two feet below the bottom of the UST in native soil, either using the backhoe bucket if reachable or using a stainless steel hand auger. Samples were placed in stainless steel sample rings, the ends were covered with Teflon tape and caped, and the samples were placed in a Ziploc bag and into a cooler with ice. Samples were delivered within one day to Associated Laboratories of Orange, California for analysis under strict chain- of-custody procedures. After receiving the soil analytical results from the stockpiles soil which indicated that the stockpiled overburden was clean, the stockpiled soils were placed into the UST excavation in 2 foot lifts and compacted to 90%relative density. In addition, the balance of the excavation was backfilled with soil obtained by Tafoya and Associates from a nearby CALTRANS project. This material was placed in the upper portion of the excavation in two foot lifts and was compacted to 95% relative density. The soil density for the backfilled excavation and trenches was tested by North American Technical Services on January 15, 17, and 20, 2014. Relative density was measured at 14 locations and ranged in relative densities from 90%to 97%. Copies of the bulk density test results for the backfill material and a summary of in place measured densities is included in Appendix E. . Photo documentation of the entire UST removal process is included in Appendix F. 2.2 UST Tank Pit, Stock Pile and Dispensers Soil Sampling Activities Soil samples were collected from beneath the USTs and fuel lines, and from the soil stockpiles on January 9, 10, and 15, 2014 as described below. Soil samples were collected from beneath each of the three USTs at both ends and the middle of the tanks (Figure 2). The samples were labeled according to the UST fuel grade and orientation of the samples (T91-W-18', T91-E-18', T91-M-18',T89-N-18', T89-S-18', T89-M-18',T87-W-18', T87-E-18', and T87-M-18'). Soil samples were collected approximately every 20 linear feet from beneath the fuel lines at a depth of approximately 2 feet bgs, with a total of five samples collected (P-1-2', P-2-2', P-3-2', P-4-2', and P-5-2'; Figure 2). Soil stockpile samples were collected after exposing a fresh surface of soil at 4 locations (SP-1, SP-2, SP-3, and SP-4; Figure 2) from the approximately 100 cubic yard soil stockpile, representing the required sampling frequency of 2 samples every 50 cubic yards. Waterstone collected these samples onsite at the direction of the SJCEHD inspector in stainless steel rings. These soil samples were analyzed by Associated Laboratories of Orange, California, which is a certified laboratory for the analyses performed which included TPI-Ig by EPA Method 8015 Modified and BTEX, MTBE, DIPE, ETBE, TAME, TBA, EDB, and 1,2-DCA by EPA Method 8260B. Vapor emissions from each soil sample were also measured by placing approximately one cubic inch of soil inside a sealed plastic bag, crumbling the soil sample and allowing it to off-gas in the bag for approximately three minutes, measuring t� RC C V tL.�i GENP j+)he bag headspace Thrifty Station No. 171 3 FEB 2 6 2014Waterston Environmental,Inc. February 2014 Project 13-140 ENVIRONMENTAL HEALTH DEPARTMENT