Former NAS Moffett Field

Status of Site 25Status of Site 25

Restoration Advisory Board MeetingSeptember 10, 2009

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Presentation Overview

Site 25 refresher• Location• Contamination• Risks• Remedial action objective

Current status and path forward

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Site 25 Location & Description

• Located in the northwestern corner of NAS Moffett Field

• Stormwater system managed by NASA (except for Stevens Creek Shoreline Nature Study Area)

• Stormwater flows through NASA settling basin to Eastern Diked Marsh and into the stormwater retention ponds

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Site 25 Contamination

Sediment contains lead, zinc, polychlorinated biphenyls (PCBs), and DDT (dichlorodiphenyltrichloroethane)

Contamination likely from discharge of stormwater to Site 25 andapplication of DDT

Potential upland source areas are being addressed separately

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Site 25 Risks

Risks to human health are acceptable

• Risk will be further reduced by remedial action to address ecological risk

Risk to site wildlife is driving remedial action

• Remedial action based on tidal marsh scenario (most sensitive habitat)

• Lead, zinc, DDT, and PCBs pose unacceptable risk to invertebrates, birds, and mammals

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Remedial Action Objective

Reduce exposure to concentrations of lead, zinc, DDT, and PCBs in sediment at Site 25 to levels that are protective of ecological receptors if the site contains a tidal marsh in the future

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Selected Remedy

Focused Treatment

• Treat sediment contaminated with only lead and zinc• Stabilize lead and zinc so soil can be disposed of as non-

hazardous waste

Excavate sediment and dispose off site

Restoration - backfill wetland habitat, as needed, and re-vegetate with native plants

Ecological Monitoring - of the wetland areas during the construction to evaluate recovery

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Selected Remedy

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Site 25 Current Schedule

Proposed Plan• Submitted January 9, 2009• Public Meeting on January 22, 2009

Record of Decision• Draft ROD out on April 30, 2009• All comments back on July 29, 2009

Draft final ROD due out on September 29, 2009• Final ROD October 29, 2009

Note – ROD includes Responsiveness Summary

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Site 25 Path Forward

Finalize Record of Decision - October 29, 2009

Begin Remedial Design – Mid 2010• Currently working through contract award • Request funds at the beginning of FY 2010

Remedial Action – Early 2011

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Questions?