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CAMBRIA • information that indicates this property used to be occupied by a service station we are reconsidering our proposed scope of work north of the Shell site Considering the following information o The predominant groundwater flow direction beneath the Shell site is toward the southeast o The northern dispenser island is the suspected source area of petroleum hydrocarbons for the Shell site o The petroleum hydrocarbon concentration gradient between the S-1/S-1-85 well cluster and the S-4/S-4-83 well cluster indicate petroleum hydrocarbons are migrating southeast from the suspected source area and show a decreasing concentration trend with distance away from the source area a Cone penetration testing (CPT) boring SB-18 was drilled on the northern side of East Fremont Street, immediately adjacent to the 2491 East Fremont property (along it's southern boundary) during our November 2002 investigation (Cambria's March 6, 2003 Site Investigation Report) o Petroleum hydrocarbons and 1,2-DCA were detected in groundwater samples collected from SB-18 at various depth intervals Maps and tables displaying these data are included in . Appendix B It does not seem likely that the petroleum hydrocarbons and 1,2-DCA encountered in SB-18 migrated upgradient from the northern dispenser island area on the Shell site It seems more likely that these detections in SB-18 originate from an offsite source (possibly the former service station at 2491 East Fremont Street) i i Based on this new information, the exploratory borings we have proposed on the 2491 East Fremont Street parcel may not serve their intended purpose of delineating the upgradient extent of 1,2-DCA north of the Shell site It is likely that these borings would encounter residual petroleum hydrocarbons (and possibly 1,2-DCA) from the former service station in soil and groundwater We believe the city directory report and the analytical data from SB-18 provide sufficient evidence to warrant investigation of the 2491 East Fremont Street property by the former owner or operator of the service station T Based on the above, we would-like to revise our scope of work for the pending_investigation-to no longer include borings SB-26, SB-27, and SB-28, which were proposed on the 2491 East Fremont property (the former service station) Revising the scope of work in this way will result in us needing one less access agreement for this phase of work • 0797 3