ARCHIVED REPORTS_SOIL AND GROUNDWATER INVESTIGATION REPORT 2008

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' Soil and Groundwater Investigation Report Vernalis Offsite June 2008 ' 3.3 INVESTIGATION-DERIVED WASTE (IDW) To properly store,characterize, and dispose of IDW, SAIC conducted the following: • Placed all IDW(soil cuttings and unused soil sample,disposable sampling equipment,used personal protective equipment, and decontamination water) in 55-gallon drums. • Properly labeled, secured, and stored IDW-containing drums on site pending disposal by ' Sturgeon &Son,Inc.. 4. FINDINGS 4.1 SUBSURFACE CONDITIONS Soils at the site ranged from silty clay to poorly graded sand with silt and gravel. Boring logs, which describe Unified Soil Classification System soil characteristics; photo-ionization detector readings; and ' observations of residual crude oil in soil and/or groundwater are provided in Appendix C. Petroleum hydrocarbons were not observed in any boring. Groundwater was encountered at depths ranging from 32 to 39 feet bgs. 4.2 SOIL ANALYTICAL RESULTS Soil analytical results,PRGs, and ESLs for the COCs are summarized in Tables 1 and 2. A soil data usability discussion is included in Appendix D as Appendix D.1, and copies of the soil laboratory reports are included as Appendix D.2. Section 5.1 compares soil results to the PRGs and ESLs to assess the extent of affected soil and whether any further soil characterization is appropriate. ' 4.3 GROUNDWATER ANALYTICAL RESULTS Groundwater analytical results,ESLs, and WQOs are summarized in Tables 3 and 4. Table 5 summarizes the General Minerals analytical results. A data usability discussion is included in Appendix D as Appendix D.1, and copies of the groundwater laboratory reports are included as Appendix D.2. Section 5.2 compares the groundwater results to the ESLs and WQOs to assess the extent of affected groundwater and whether any further groundwater characterization is appropriate. 4.4 DATA USABLITY SUMMARY SAIC performed a data usability evaluation to determine whether the data could be used for the intended purposes (i.e.,delineation and risk evaluation). The evaluation determined that all analytical data are usable. See the Data Usability Summary in Appendix D.1 for more information. Qualified data with reason codes are provided in Table D-1 and are summarized in Appendix D.1. i5. DISCUSSION OF PETROLEUM DISTRIBUTION 5.1 EXTENT OF AFFECTED SOIL Soil analytical results were compared to the lowest, most conservative PRG and ESL concentrations for delineation purposes. Soil sample analytical results obtained in the course of this investigation were less than PRGs and ESLs. 5.2 EXTENT OF AFFECTED GROUNDWATER Groundwater analytical results were compared to the lowest, most conservative ESL and WQO concentrations for delineation purposes. Groundwater sample analytical results obtained in the course of this investigation were less than PRGs and ESLs,with the following exceptions: • TPHd: SB-26 and SB-33 (160 µg/L and 240µg/L, respectively); • Benzo(a)anthracene : SB-33 (0.039 µg/L); and 6 From Science to Solutions