3B Public Hearing 2009 0720 - Laserfiche WebLink

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PLN2008-00030; Cornerstone at San Leandro Crossings Mitigated Negative Declaration March 20, 2009 o If the soil contains COPCs at levels that exceed the relevant health -based screening levels, or if the State regulatory agency concludes that an unacceptable risk to construction worker or future residents may be present, then management measures, such as the following, will be undertaken: ■ Remove the impacted soil and dispose of off -Site; ■ Install a cap to prevent contact with the contamination; ■ Install a physical barrier for vapors such as a vapor barrier or passive venting system, to prevent the accumulation of vapors in indoor environment; ■ Stockpile soil and aerate on -Site, or in a staging area as may be appropriate, in compliance with all applicable laws and regulations; ■ Conduct in situ bioremediation measures; or ■ Implement liquid or vapor extraction measures. The appropriateness of one of the above management measures over another will depend on many factors, such as the type of constituent detected, the size of the identified impacted area, and the estimated cost of implementing the remedy. Results of the sampling activities and the proposed course of action, e.g., no action necessary, soil excavation and off -Site disposal, on -Site treatment and soil reuse, shall be reported to a State environmental regulatory agency and the contractor shall obtain concurrence before implementing the remedial measures. Construction activities in the specific area where the unknown conditions were identified will resume following the completion of the additional sampling activities and the implementation of any required responses. Any cleanup or remediation shall be required to meet applicable federal, state and local laws, regulations and requirements. Imported Fill: To minimize the potential introduction of contaminated fill onto the Sites, all imported fill shall have adequate documentation so it can be verified that the fill source is appropriate for the Site's intended use. Documentation shall include detailed information on previous land use of the fill source, any Phase I Environmental Site Assessments performed and the findings, and the results of any analytical testing performed. If no documentation is available or the documentation is inadequate or if no analytical testing has been performed, samples of the potential fill material shall be collected and analyzed. The analyses selected shall be based on the fill source and knowledge of the previous land use as determined by the developer's environmental consultant. The sample frequency for potential fill material shall be in accordance with that outlined in the Department of Toxic Substances Control technical document titled, "Information Advisory on Clean Imported Fill Material". The developer's environmental consultant shall approve the use of imported fill. I2