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v V. M K L E I N F E L D E R At this time Kleinfelder is not proposing excavation in Area A (See Plate 3), since field observations and analytical results in this area from Kleinfelder's previous pushprobe assessment does not appear to wan-ant remedial activities. The purpose of the proposed excavation activities is to remove petroleum impacted soil from the petroleum spill area. Based on verbal conversation with Steven Shih of SJC/EHD the expressed clean up goal for soil in the spill area should be none detected at or above the laboratory reporting limits. This is also consistent with the desires of the developer, Pegasus MH Ventures I. Mr. Gabe Karam, Development Manager, with Mountain House Community Service District was contacted regarding contaminants related to the project spill area. Mr. Karam stated their position is "zero detect for petroleum constituents in the future right-of-ways and any areas which may become public, such as parks and recreational areas." Therefore, Kleinfelder is proposing a clean-up goal of none detect for the petroleum constituents as listed in Task 3. Kleinfelder proposes collection of approximately thirty (30) discrete bottom excavation soil samples based on a 50 foot grid pattern. Kleinfelder estimates the average depths of the bottom soil samples to be approximately 12 to 20 feet bgs as shown on Plate 4. The average depth of bottom soil samples is estimated at 12 feet in Area B (west and northwest portion of footprint area) and 15 feet in Area C (central area). Confirmation bottom soil samples are estimated at a depth of 20 feet bgs in Area D (eastern area). Kleinfelder proposes collection of approximately twenty four (24) sidewall samples around the perimeter of the estimated excavation boundaries at 40 to 60 foot intervals as shown on Plate 4. The interval variances are based partly on proximity to excavation bottom samples to the estimated sidewall locations. At this time Kleinfelder proposes the sidewall confirmation sampling depths to approximately coincide with the estimated total depth of obvious petroleum impacted soil as illustrated on Plate 2. Therefore, Kleinfelder proposes excavation sidewall soil sampling depth within Area B to average approximately 5 feet bgs and the average sidewall sample depth of 8 feet bgs in Area C. The average sidewall soil sample depth in area D is proposed at approximately 12 feet bgs. The rational for these proposed sidewall depths is to assess lateral migration of petroleum constituents in soil, which based on previous analytical results, field observations, and length of time that has elapsed since the spill has been impacted by a relatively greater concentration of petroleum constituents. Previous soil sampling locations and analytical results from Kleinfelder's pushprobe assessment will be used to evaluate actual confirmation soil sampling locations and depths. A Photo-ionization detector (PID) will be used during excavation activities as a screening tool to assess the potential limits of petroleum impacted soil. The potential and actual confirmation soil sampling location will be field screened using the PID and recorded for reporting purposes as described in Appendix B, Section B-2.2. The soil samples from within the excavation will be collected from the bucket of an excavator or by using a stainless steel core barrel attached to extension rods and a slide hammer. The stainless steel tubes will be removed from the soil and the ends sealed with Teflon tape and tightly fitting plastic caps. The samples will be placed immediately into an iced cooler. The samples obtained will be transported under chain-of-custody control to Kleinfelder's office and 44843.T04/ST04R1121r Page 4 of 9 Copyright 2004,Kleinfelder,Inc. September 2,2004