ARCHIVED REPORTS_DRAFT - PHASE I REMEDIAL INVESTIGATION REPORT

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Kennedy/Jenks Consultants 3.2.1 Soil Sample Collection Portions of acetate liners selected for analysis were cut from the main acetate liner, sealed with Teflon TM tape, capped, labeled, placed in a chilled cooler, and recorded on the chain-of-custody. The sample identification followed the naming convention described in the SAP. 3.2.2 Groundwater Sample Collection Borings were drilled to 20 feet bgs to collect groundwater samples. Following soil classification and sampling, and upon reaching the uppermost groundwater surface, the direct-push sample barrel and inner rods were removed and new slotted polyvinyl chloride (PVC) casing was installed in the borehole. Groundwater samples were collected from within the PVC casing using new disposable tubing fitted with a reusable steel check valve. Groundwater samples were collected in OU-2 at the locations specified in the RI Work Plan except for Boring OU2-AO16-S1. Mechanical refusal was encountered at 8 feet bgs at this boring (possibly due to the concrete base of the former turntable) and a groundwater sample was collected at Boring OU2-AO16-S3 instead. The boring locations proposed in OU-5-AI010 were modified from the proposed locations in the Addendum as the investigation progressed. Evidence of Geocon borings (the tops of the grouted borings) was found near some of the proposed boring locations in the northwest portion of AOI 10 and so the proposed boring locations were moved to avoid duplicating Geocon's findings. Some boring locations were shifted northward to find the limit of the visible hydrocarbon impact. After the initial borings were drilled in western AOI 10 and the northern and southern limit of the visible hydrocarbon impact was found, in January 2006 additional Borings OU5-A0110-S13 through OU5-A0110-S17 were drilled on the west side of the railroad tracks to further evaluate the western limit of the hydrocarbon impact. Groundwater sampling was performed in accordance with the procedures presented in the RI Work Plan and Addendum. 3.2.3 Test Pit and Trench Sample Collection The test pits and trench locations are shown on Figure 4. ITest pits and trenches were excavated with a John Deere 310E backhoe. Soil samples were collected from the sidewall of shallow test pits by forcing a 6-inch long metal liner into the sidewall until the liner was full, then sealing the liner with Teflon TM tape and caps. Samples from deeper trenches were collected from material contained in the backhoe bucket. The observations and findings from the test pits and soil samples are discussed in Section 4. tLogs of trenches are included in Appendix B. 3.2.4 Replacement Borings • Review of analytical data reports by Kennedy/Jenks revealed that the laboratory exceeded the hold time for VOC analysis of some soil samples collected in OU-2. To replace these samples, DRAFT Phase I Remedial Investigation Report Page 17 Former Tracy Railyard, Tracy, California g:Gs-groupladminljob10510565777,18_uprr109-reportslri rpQext.doc