SITE INFORMATION AND CORRESPONDENCE

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Soil and Groundwater Investigation Report Vernalis Pump Station August 2006 Up gradient of the BelliniBogetti and Arcos property plumes,the extent of affected groundwater is delineated on the site at the following locations, from north to south: soil boring SB-30; monitoring wells MW-3 and MW-4; and soil borings ASB-2,ASB-3, and ASB-9. Up gradient and west of these sample locations,the constituents of concern in numerous groundwater samples were either non-detectable or well below the WQOs. Therefore,the up-gradient extent of affected groundwater is defined. 5. DISCUSSION AND RECOMMENDATIONS Based on the results of this investigation, SAIC concludes the following regarding the nature and extent of crude oil impacts at the site: • Based on the previous site investigations, affected soil and groundwater are delineated vertically to a maximum depth of approximately 80 feet bgs. The RWQCB approved these delineation results in their letter dated March 19, 2004. • In the immediate vicinity of the boiler house and the pump house,the lateral extent of affected soil is defined by several borings located near monitoring well MW-1. • In addition to the small groundwater plume centered on MW-1,two additional plumes of affected groundwater are present on and off site: the Arcos property plume,which encompasses Geomatrix borings ASB-1,ASB-4,ASB-5,ASB-6,ASB-7, and ASB-11; and the Bellini/Bogetti property plume,which includes borings SB-15, SB-16, SB-18, SB-19, SB-20, SB-23 (MW-6), SB-24, SB-25, and monitoring well MW-7. • Up gradient,the extent of affected groundwater is delineated on the site at the following locations, from north to south: soil boring SB-30;monitoring wells MW-3 and MW-4; and soil borings ASB-2,ASB-3, and ASB-9. • The extent of affected groundwater is undefined at boring SB-25 and at monitoring well MW-7, and further off-site investigation is necessary down gradient on the Bogetti property. • The extent of the Arcos property plume is undefined, and off-site investigation is necessary down gradient on the SJVHGA property, or in the Highway 33 ROW. In order to define the extent of affected groundwater down gradient and off site(east of Highway 33), SAIC proposes the following: • Install seven borings(SB-26, SB-27, SB-28, SB-29, SB-31, SB-32, and SB-33) from which groundwater samples will be collected for laboratory analysis of the constituents of concern. For more details regarding the proposed borings,refer to Figure 5 (Site and Exploration Map with Proposed Soil Boring Locations) and Table 6 (Proposed Boring Objectives). The proposed additional investigation will be described in a work plan to be submitted under separate cover. Because site access to the SJVHGA property has been difficult to obtain, it may require the intervention of the RWQCB to assist or lead CEMC efforts to secure access. Otherwise,borings SB-31 through SB-33 should be relocated to the Highway 33 ROW. If no site access can be obtained, SAIC will delineate the extent of crude oil impacts,to the extent practicable. SAIC will also complete four quarters of groundwater monitoring and a human health risk assessment. After regulatory approval of the risk assessment and cessation of the groundwater monitoring and sampling program, it is anticipated that a letter of No Further Action for the site will be requested from the RWQCB. 7 From Science to Solutions-