ARCHIVED REPORTS_WELL ABANDONMENT, SOIL AND GROUNDWATER INVESTIGATION REPORT 2009

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Monitoring Well Destruction and Soil and Groundwater Investigation Report US Can—Welty Road September 24,2009 Petroleum hydrocarbon-affected (affected) soil was observed in SB-18 SB-20 through SB-26 (including SB-24a), SB-28, SB-29, SB-34, SB-35, SB-38 through SB-41, and SB-43 at depths ranging between 7 and 76 feet bgs. The lithology of the investigation area consisted primarily of clays and silts to an approximate ' depth of 15 feet bgs. Below 15 feet bgs, alternating zones of fine-grained clays and silts and coarser-grained silty/clayey gravels, well-graded gravels, and poorly to well-graded sands were observed. Coarse-grained sediment was typically observed between 24 and 44 feet bgs, and was Icommonly interbedded with laterally discontinuous layers of fine-grained sediment. Groundwater was initially encountered between 31.5 and 51 feet bgs. Determination of the groundwater flow direction and gradient was not a component of this investigation. As noted in section 2.4, groundwater flow direction is toward the east. Boring locations are depicted on Figure 2. The boring logs, which contain soil descriptions using the Unified Soil Classification System (USCS),photo-ionization detector (PID) readings, and observations of affected soil and/or groundwater, are provided in Appendix D. Boring locations were surveyed for longitude and latitude coordinates within a 5-foot range using a Global Positioning System with reference to the North American Datum 83 State Plane Zone 3. 4.2 SOIL ANALYTICAL RESULTS Soil analytical results and ESL and RSL screening levels are summarized in Tables 1 and 2. Soil analytical results that exceed screening levels are indicated in Tables 1 and 2, and on Figures 3a and 3b. A data usability discussion is included in Appendix E.1, and copies of the soil sample laboratory analytical reports are included as Appendix E.2. 4.3 GROUNDWATER ANALYTICAL RESULTS Groundwater analytical results and ESL and WQO screening levels are summarized in Tables 3 and 4. Groundwater analytical results that exceed screening levels are indicated in Tables 3 and 4, and also on Figures 3a and 3b. General minerals analytical results and ESL and WQO screening levels are summarized in Table 5. A data usability discussion is included in Appendix E.1, and copies of the groundwater sample laboratory analytical reports are included as Appendix E.2. 4.4 FUEL-FINGERPRINT RESULTS Soil samples were collected from borings SB-18, SB-20 through SB-26, SB-28, SB-29, SB-34, SB-35, SB-38, SB-39, SB-41, and SB-43 for fuel-fingerprint analysis. One sample was collected from each boring at depths ranging from 28 to 60.5 feet bgs. With the exception of the samples collected from SB-35, SB-41, and SB-43, the fuel-fingerprint analyses indicated the soil samples contained either"moderately weathered" or"extremely weathered" San Joaquin Valley crude oil (SJV crude). Minor amounts of other hydrocarbons were detected in the three samples collected from SB-35, SB-41, and SB-43, which may or may not be indicative of SJV crude. Fuel-fingerprint results are summarized in Table 6, and the CETC reports are provided in Appendix E.3. ' 4.5 DATA USABILITY SUMMARY SAIC performed a data usability evaluation to determine whether the data could be used for the 6 —5,A I-C. ' From science to solutions