ARCHIVED REPORTS ADDITIONAL SOIL SAMPLING AND ANALYSES

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' k' ■ K L E I NE ELDER ' CONCLUSIONS AND RECOMMENDATIONS ' The analytical results for the soil samples collected at the site were compared to the California Code of Regulations 22CCR§66261.24 and/or the Residential and Industrial U.S. EPA Region IX Preliminary Remediation Goals (DRGs), dated November 1, 2000. A summary of Kleinfelders observations, findings and comparison of analytical results to these regulations and goals (as applicable) are summarized below: 1) Field observations indicate that discolored soil with petroleum odors were removed from the ' sidewalls of Excavation LEC. Analytical confirmation sampling along the eastern and northern sidewalls as part of this assessment also indicate both purgeable and extractable hydrocarbons were not present in the sidewall samples collected. BTEX compounds were ' also not present from soil samples collected in the northern and eastern sidewall samples with the exception of xylenes, which was detected at a concentration of 7.7 µg/kg in a eastern sidewall sample at a depth of 7 feet bgs. 2) Field observations also indicate that discolored soil with petroleum odors were removed from the sidewalls and bottom of Excavation SE-D. Analytical results show that both purgeable ' hydrocarbons and BTEX constituents were not present in sidewall and bottom samples collected within SE-D. A single extractable hydrocarbon TPH-D was detected at 2.2 mg/kg in a sample collected from a north sidewall sample at a depth of approximately 2-1/2 feet ' bgs. No other extractable hydrocarbons were otherwise detected in soil samples collected in SE-D. ' 3) The location of the newley assessed area SE-D is located south of LE-C on proposed Lot 22. This location is also in close proximity and appears to transect a fonner soil excavation of six diesel USTs. ' 4) The concentrations of totals xylenes and TPH-D detected in this limited soil assessment in Kleinfelder's opinion would not generally trigger requirements for additional investigation or ' cleanup from local or State agencies. ' S) Four of five metals analyzed for including Cr, Pb, Ni and Zn were detected in each of the fourteen soil samples collected in excavations LE-C and SE-D. The total metal concentrations detected were found to be below the California Code of Regulation hazardous ' waste criteria as expressed in 22CCR §66261.24. Total metal results were also below residential PRGs levels for soil. In Kleinfelder's opinion the metal concentrations detected in the soil samples collected in this assessment are reflective of naturally occurring background ' levels. 6) Based upon the analytical results within this report Kleinfelder does not recommend further sampling or remediation in the two areas LE-C and SE-D discussed within this addendum report. However if additional soil staining or unusual odors are noted during construction 20-4341-1I.EOI/201IL635 Page 5 of 8 Copyright 2001 Kleinfelder,Inc. September 24,2001 1