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i I ARCADIS Ms. Lori Duncan March 20, 2009 I Following completion of groundwater sampling, the temporary well was removed and the borehole was tremie grouted to ground surface. A concrete patch, dyed to match the surface condition, was used for the surface completion. Groundwater Analytical Results TPH-DRO, TPH-MO, benzene, total xylenes,and TBA were detected at . concentrations of 2,700, 160, 4, 1, and 3 micrograms per liter(ug/L), respectively. All other constituents analyzed were not detected above the respective laboratory MDL. ! Groundwater analytical data are summarized in Table 2. The analytical report and chain-of-custody documentation are presented in Attachment 5. Benzene was the only analyte detected in groundwater at a concentration above the California Primary MCL. The benzene concentration in the grab groundwater sample collected from temporary well SB-2 was 4 ug/L, which is slightly above the.California LPrimary MCL(1 ug/L). Investigative Derived Waste Soil cuttings generated during drilling operations were containerized in 55-gallon drums and temporarily stored on the subject property pending characterization and disposal. On February 25, 2009, the soil wasremovedfrom the subject property and disposed of at Republic Service Vasco Road Landfill in Livermore, California. Manifests are included in Attachment 6. Summary and Conclusions i The results of the recent site assessment are summarized below: • 1,2-DCA concentrations detected in soil samples collected from.SB-2 at 60, 70, and 80 feet bgs were above RWQCB ESLs; all other detections were below RWQCB ESLs •. No analytes were detected above the laboratory MDLs in soil samples collected below 135 feet bgs • Benzene was the only analyte detected in the groundwater sample collected at 115 feet bgs; all other detections were below California Primary MCLs z PP1. "_PN �Me— � � Page: 6/7 Parca�6 %ofriicedala\SacramentaCA\ENVACHEVRONM907516 DeIN8raNes\Reports\As S.Ft A A �J'(�/tit{[[1C[K f Moe -