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AW Site Background Information: California Stop Page 5 of 7 2, MW-3 and MW-6 as extraction points,took place at the site. Results of the groundwater batch removals and post-removal monitoring event included the following: • In general groundwater draw-down was noted at all extraction points. Maximum draw-down (4.85 feet) was measured in well MW-1 during the fifth batch removal. • Groundwater draw-down was generally absent in monitoring wells surrounding the extraction points. • MTBE was reported in all 38 groundwater samples analyzed during the batch removal activities. MTBE concentrations were reported as low as 260 pg/I (MW-3 - post-batch removal sampling event)and as high as 82,000 pg/I(MW-1 -1/26/2010). • In general, MTBE concentrations appeared to steadily increase during the batch removals in wells MW-1 and MW-2. It appears residual, elevated concentrations surrounding the former tank and dispensing area, mobilized toward the extraction points. This would be consistent with the steady increase in MTBE concentrations during the batch extraction and the decline in concentrations following termination of extraction. • In general, MTBE concentrations in wells MW-3 and MW-6 exhibited overall downward trends during the batch removals, based on the intra-well trends. • Post-batch removal groundwater samples collected in February 2010 indicate an overall increase in MTBE concentrations when compared to a pre-batch removal sampling event conducted in October 2009. This further indicates the mobilization of dissolved MTBE towards the extraction points. • TBA concentrations exhibited overall downward trends in all wells during the batch removals. Furthermore, post-batch removal groundwater samples collected in February 2010 all indicate overall decreases in TBA concentrations when compared to a pre-batch removal sampling event conducted in October 2009. • A total volume of 27,400 gallons of groundwater was extracted during the batch events, with a total of 0.32 pounds of MTBE removed from groundwater as a result of the batch extractions. STRATIGRAPHY Based on soil boring logs acquired during various phases of site assessment and supplemented by cone penetration test data, soils at the site generally consist of brown, fine-grained material (silt, clayey silt, silty clay, and sandy silt) encountered from surface grade to approximately 25 feet or 30 feet bsg. Sand or silty sand was encountered at depths of between 5 feet and/or 10 feet bsg in borings B2 through B6, MW5 through MW8, B8, B9 and CPT-1. Sand and silty sand were identified from approximately 29 feet to Advanced GeoEnvironmental,Inc.