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Soil and Groundwater Investigation Report Catellus Property September 2006 In order to assess whether water supply wells of concern(Map ID Nos. 15, 18, and 22)have been affected, SAIC proposes to: • Gain access to these wells and sample the groundwater for laboratory analysis of the constituents of concern. In order to further assess the lateral extent of affected soil and groundwater near the apparent source area of SB-8, SAIC proposes to: • Advance four borings(SB-38, SB-40, SB-41,and SB-42)adjacent to SB-8,each approximately 75 feet away. In order to define the vertical extent of affected groundwater at SB-I (North Plume)and SB-8 (Central Plume), SAIC proposes to: • Advance companion borings at those locations from which discrete-depth grab groundwater samples will be collected from beneath the zone of affected soil and tested for the constituents of concern. In order to define the vertical extent of affected soil and groundwater where it is undefined at SB-20 (South Plume),SAIC proposes to: • Advance a companion boring at SB-20 from which a soil sample and a discrete-depth grab groundwater sample will be collected from beneath the zone of affected media and tested for the constituents of concern. In order to define the up-gradient extent of affected groundwater(west of the drainage channel on the west side of Byron Road), SAIC proposes the following: • Install eight borings(SB-52 to SB-59)up gradient of the South Plume from which groundwater samples will be collected for laboratory analysis of the constituents of concern. In order to define the down-gradient extent of affected groundwater(east of Byron Road), SAIC proposes the following: • Install two borings(SB-60 and SB-61)down gradient of the North Plume,two borings(SB-25 and SB-28)down gradient of the Central Plume,and eight borings(SB-62 through SB-69)down gradient of the South Plume 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 more detail in a work plan to be submitted to the RWQCB under separate cover. After regulatory approval of the proposed work plan, SAIC will implement future additional characterization activities. Because access to Assessor Parcel Numbers 209-27-010,209-27-011,and 209-27-030 has in the past been difficult to obtain,it may require the intervention of the RWQCB to assist or lead CEMC efforts to secure access to proposed borings SB-62 through SB-69 on these parcels. If site access to the these parcels is denied,the borings may be located in the UPRR ROW. 7. LIMITATIONS SAIC's investigation was restricted to collection and analyses of a limited number of environmental samples and visual observations obtained during the physical site visit,and from records made available (by CEMC or third parties)during the investigation. Because the investigation consisted of collecting 8 From Science to Solutions-