ARCHIVED REPORTS_1ST QUARTER 2008 SITE STATUS REMEDIAL SUMMARY AND GROUNDWATER MONITORING REPORT

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S E C O R • Validation issues with report number 60774: Values reported for p,m-xylene that are below the MRL should be considered estimates. Values for p,m-xylene are reported to the lower CRDL of 0.50µg/L. The method reporting limit for TPHd was increased due to interference from gasoline range hydrocarbons for samples MW-4 and QCDUP-4. The method reporting limit for chloromethane was increased due to the presence of an interfering compound for sample QCDUP-4. Surrogate 2,4,5-tribromophenol was out of QC limits for percent recovery in sample MW-20. All other surrogates were in range. SVOCs were not detected in sample MW-20. The surrogate is not anticipated to be an issue with reported values for this sample. 4.4 First Quarter 2008 Deeper Groundwater Results 4.4.1 Deep Zone (B, C, and D-Zone) Groundwater Gradient B-Zone groundwater elevations at the Site ranged from 8.63 feet below MSL in well MW-53 to 0.05 foot above MSL in well MW-44 (Table 3 and Figure 10). Groundwater flow during the first quarter 2008 in deeper groundwater is generally to the northeast. The highest B-Zone groundwater elevation (0.05 foot above MSL) was reported in well MW-44, located in the southwest portion of the Site west of Mormon Slough. Calculated hydraulic gradients for the • B-Zone data collected during the first quarter were 0.011 ft/ft to the north/northwest in the northwestern portion of the site, 0.011 ft/ft to the northeast in the southeastern portion of the site, and 0.016 ft/ftto the east/northeast in the central portion of the site (Figure 10). The overall historic trend of the B-Zone gradient is to the east-northeast. Historical groundwater flow direction and gradient data are summarized in Table 8, and vertical gradients summarized in Table 9. The B-Zone groundwater elevation contour map for the January 21, 2008 monitoring event is included as Figure 10. Groundwater elevations in the C- and D-Zones were 8.81 feet (MW-54) and 8.92 feet below MSL (MW-55), respectively. 4.4.2 Deep Zone Groundwater Quality Data During the first quarter 2008, groundwater samples were collected from 14 deep zone wells between January 21 and 25, 2008 (Table 1). Groundwater analytical results are presented in Tables 4 through 7, and summarized below. TPHg, TPHd, TPHo, benzene, MtBE, and TBA isoconcentration contour maps are included as Figures 11 through 16, respectively. Groundwater analytical data for the C-Zone and D-Zone are shown on Figure 17. The certified laboratory analytical reports for the groundwater sampling event conducted for the L&M OU are included in Appendix C. 4.4.2.1 SPH During the first quarter 2008, measurable SPH or SPH-sheen was observed in nine wells. SPH • thicknesses for deep zone wells are summarized below. 1 Q08QSSRQRSRQMR.Final.doc 16 April 30,2008 _ 77TW.26397.42.1307