Energy and Environmental Consulting

PM STRAUSS & ASSOCIATES

Energy and Environmental Consulting

MEMORANDUM

TO:Lenny Siegel

FROM:Peter Strauss

DATE:June 15, 2012

SUBJ:Update on Moffett/MEW Status in Preparation for Comments on the Groundwater Feasibility Study

Introduction

This memo is intended to provide background information and recent reference material to help evaluate the Draft Groundwater Feasibility Study that was recently released, in conjunction with recent vapor intrusion sampling and issues. It provides no conclusions or recommendations – it is merely a summary of recent reports. These reports include the 2011 site-wide vapor intrusion sampling report, the 2011 Annual MEW Regional and Site-specific Groundwater Progress Reports, and the 2011 Annual Reports on the Moffett Field East-Side and West-side areas.

Work on the Groundwater Focused Feasibility Studyis expected to continue through 2012. It should be kept in mind that this report should encompass the results of the optimization reports and results of bioremediation tests at the Intel/Raytheon and Moffett sites. One goal is to identify alternatives to the groundwater remediation strategy that would increase the rate of cleanup so that the vapor intrusion remedies are not longer needed.

My analysis of the preliminary draft Groundwater Feasibility Study will the subject of a separate memo. The proposed plan is scheduled sometime between October and December 2012.

Site-Wide Vapor Intrusion Sampling and Remedy Implementation

The responsible parties have been submitting indoor air samples for 11 buildings. Six buildings were samples with the HVAC system on, four with them off, and one building with the system both on and off. In 2011, indoor and outdoor air samples collected in 2011 in each of the following buildings. All indoor air samples collected during this reporting period showed COC concentrations lower than EPA’s cleanup levels established in the ROD.EPA approvedthe Moffett Field sampling portion of this plan, and inMay 2012 the Navy submitted a final Workplan.

In September 2011, Haley & Aldrich submitted a Site-Wide Vapor Intrusion Sampling and Analysis Work Plan for Response Action Tiering. It is expected that implementation of the VI remedy will begin after the plan is approved. EPA confirmed that annual progress reports for VI were not required until after the Work Plan is approved. No interim VI mitigation measures were reported to date.

In 2012, indoor and outdoor air samples from the unsampled buildings will be collected. Buildings both south and north of 101 have tested positive (exceeding remedial action levels) and in several cases, including renovation of buildings above the plume and the boiler room at Moffett, concentrations in indoor air have exceeded EPA’s proposed Removal Action Level (RAL), which is proposed for short term remediation. EPA has proposed in each of these cases that the buildings either add additional ventilation or indoor air filtration systems that would bring these levels down below the proposed RAL. In the case of the boiler room at Moffett, very high concentrations were found in a preferential pathway (a steam tunnel) and this will require additional care.

Supplemental Building/Property-Specific Vapor Intrusion Sampling and Analysis Work Plans will be prepared per the schedule provided in the Tiering Work Plan. An Institutional Controls Implementation, Management, and Monitoring Plan will be submitted within 60 days of EPA approval of the final Tiering Work Plan.

MEW Annual Reports

Each MEW site prepared a 2011 Annual Report, which was sent to distribution in April 2012. Below are short summaries of these reports.

Renesas Electronics (formerly NEC Electronics) @ 501 Ellis

The site is a single story building of about 28,000 square ft. Soil and groundwater remedial actions were implemented in the 1990s. After soil excavation, groundwater extraction and treatment and has been operating continually since 1997. It is based a pump and treat system using granular activated carbon (GAC) to treat the groundwater. In 2008, the system extraction ratewas adjusted, and one extraction well was turned off (although left in place should the need arise). Operation includes direct discharge of extracted groundwater to the Palo Alto RWQCP and is conducted under the requirements of a City of Mountain View Wastewater Discharge Permit.

The highest TCE concentration detected during the October 2011 sampling event was 140 micrograms per liter (μg/L). This is slightly greater than the highest TCE concentration detected in 2010, which was 130 μg/L.Since May 2000, TCE concentrations have been below 500 μg/L. Since shutting down extraction at NEC-1AE in May 2009, concentrations of cis-1, 2-dichloroethene (cis-1, 2-DCE) have nearly doubled, indicating that ongoing natural attenuation processes at the Site may occur with increased efficiency in the absence of groundwater extraction.Since start of operation, 33 million gallons have been extracted and 43 pounds of VOCs have been removed. Since 2009, with increased groundwater extraction rates, the VOC removal rate has almost doubled, while the efficiency of extraction (VOCs extracted/gallons of water extracted) has decreased slightly.

In March 2011, EPA suggested that Renesas propose a trial shutdown of the source control system. The objectives of the trial shutdown would be to assess plume stability in the absence of groundwater extraction and evaluate whether monitored natural attenuation (MNA) is a viable alternative remedy for the Site. A Work Plan for Trial Shutdown was submitted to EPA on behalf of Renesas in September 2011. However, EPA informed Renesas that the trial shut down could not be approved until the Tiering Workplan is approved and implemented at 501 Ellis Street.

Raytheon @ 350 Ellis St.

This address was a former Raytheon building that was sold to Fairchild in 1997. It was demolished in 2000, replaced by an office campus of 5 buildings, which is now owned by Symantec.

A slurry wall was constructed in 1987. The soil remedy included soil vapor extraction (SVE) and excavation. In 2004, EPA confirmed that soil met cleanup objectives. For groundwater, a pump and treat system was used with 5 extraction wells inside wall and 3 outside. Treatment used an ozone/hydrogen peroxide oxidation system, followed by GAC. VOCs and 1,4-dioxane are oxidized. Treated groundwater flows to Steven’s Creek. During 2011, 14.4 million gallons were treated, removing 309 lbs of VOCs.

Since 2000 when property was redeveloped, an outward gradient was observed along the northern slurry wall. In 2010, a monitoring well had a reading of 6,200 g/L TCE, up from the recent historical average around 2,000 g/L. Raytheon put in two extraction wells to capture the plume. Extraction rateswere increased in 2011 in order to expand capture zone. Although concentrations were reduced in this above monitoring well, and capture was substantially improved, it was not possible to expand the capture zone.Efficiency of systems was essentially the same between 2010 and 2011.No substantial new activities planned for 2012.

For vapor intrusion, indoor air monitoring was conducted and conduits were sealed. Installation of air purification systems in the building was installed.

Former Fairchild B-9 @ 401 National

From 1966 to 1987 Former Building 9 functioned as a facility for receiving, mixing, and delivering chemicals for Fairchild. The Site is currently used as a warehouse by Adema Technologies, Inc. Manufacturing operations ceased by September 2010.

Remedy consists of a slurry wall and four groundwater extraction wells. Liquids are pumped to Treatment Facility at Fairchild System 1. (Further discussion of System 1 is provided in the 2011 Annual Progress Report for Former Fairchild Buildings 1-4.)

The report states “All of the Site wells with a statistically significant trend in TCE concentrations are decreasing or stable.” However, one MW shows increase in TCE (4,600 to 6,900 g/L, and one extraction well shows increase in concentrations 5,400 to 8,300 g/L between 2007 -2012. Some MWs show increase in cis-1, 2 DCE year-over-year. An area in the NE corner within slurry wall is between 1000 -10,000 g/L. An area outside the slurry wall, on the eastern side, has concentrations ranging in the 1,000-10,000 g/L.VC contours exhibit same pattern.

The report concludes that the Site groundwater remedy is performing as intended. No new activities are planned for 2012.

Former Fairchild B-18 @ 644 National

From 1966 to 1984 Former Fairchild Building 18 functioned as an electroplating facility for Fairchild Semiconductor Corporation.The building at the 644 National Avenue property is the original Fairchild Building 18 structure. Redevelopment plans include demolition of the existing building and construction of a parking lot for buildings on adjacent parcels. Redevelopment is scheduled to begin in 2012.

Groundwater is extracted at the Site by one Source Control Recovery Well (SCRW) operating in the A Zone, and is piped to off-Site Fairchild Treatment System 1. (Further discussion of System 1 is provided in the 2011 Annual Progress Report for Former Fairchild Buildings 1-4.)

Groundwater is also extracted from the Site by 3 regional wells and a dewatering sump (BLDG-18) located in the basement of the building. The groundwater extracted by the regional wells is pumped to the offsite Treatment System South of 101. The BLDG-18 dewatering sump is used to keep groundwater from infiltrating the basement of Building 18, which is constructed below ground surface.

The technical assessment concludes that the Site groundwater remedy is performing as intended. TCE in five years decreased from 2200 g/L to 1500 g/L at the extraction well. Cis-1, 2-DCE also has similar pattern and concentration.

Former Fairchild Buildings 13, 19 and 23 @ 369/441 North Whisman Road

From 1969 to 1987 Site functioned as a facility to produce semiconductor devices. TheSite was redeveloped in the 1990s, and was occupied by AOL/Netscape andHP/Mercury Interactive until about 2007. The Site buildings are currently undergoingtenant improvements in advance of Google occupying the buildings beginning in 2012.

In order to prevent migration of VOCs offsite, a groundwater extraction and treatmentsystem was installed at the Site beginning in 1984 and a soil-bentonite slurry wall wasconstructed at the Site from the ground surface to the A/B Aquitard in 1985.A network of 15 extraction wells (one being Regional) is used to remove groundwater from three depthintervals at the Site (Table 1). Thirteen of the 15 Site extraction wells were operational in2011. Two extraction wells were shut down with EPA approval. Extracted groundwater is then transported throughconveyance piping to a treatment facility (GAC) located at 389 N. Whisman Road (System 19). Once treated, the water is monitored and sampledin compliance with a National Pollutant Discharge Elimination System (NPDES)Permit, then discharged to a storm water sewer.

TCE concentrations range between 1,000 – 10,000 g/L within large part of slurry wall. VC concentrations range between 100 -1,000 g/L. TCEconcentrations have a stable to decreasing trend over the last ten years with one exception. In one monitoring well, TCE, cis-DCE and VC almost doubled in one sampling event in the last year, although this well has shown a large variance of concentrations from year to year, and is down from 2007.

The technical assessment concludes that the groundwater remedy is performing as intended. Approximately 56.5 million gallons of groundwater were treated and 234 pounds ofVOCs were removed by the groundwater treatment system during 2011.

Former Fairchild Building 20 and 20A @ 464 Ellis

From 1968 to the mid-1980s, Building 20 functioned as a silicon wafer productionfacility for Fairchild, and Building 20A served as the parking area. Building20 was demolished in the 1990s, and new commercial/research offices were constructedand completed over the building and parking area by early 2000.

No potential sources for VOCs were identified on the premises of Fairchild’s formerBuildings 20/20A at 464 Ellis Street. Therefore, there is no facility-specific remedy forthe Site.Although no onsite sources were identified for the TCE in groundwater beneath the Site, there are nine onsite extraction wells installed and maintained by other MEW parties VOC concentrations are steady to decreasing over time.

Former Fairchild Buildings 1-4 @ 515/545 Whisman and 313 Fairchild Drive

From the early 1960s to 1989, Former Fairchild Buildings 1-4 functioned as facilitiesfor chemical mixing and silicon wafer manufacturing. The buildings were demolished in the 1990s, and new commercial/research offices were constructed and completed by September 2000 (Jay Paul Company, 2010).

A slurry wall was constructed in 1986. A network of 20 extraction wells is used to remove groundwater from three depth intervals at the Site. Extracted groundwater is then transported throughconveyance piping to treatment facility System 1or System 3. Of the 20 site recovery wells, 13 wellsoperated in 2011, and the remaining 7 wells have been shut off with EPA approval.Once treated, the water is monitoredand sampled in compliance with a National Pollutant Discharge Elimination System(NPDES) Permit, then discharged to a storm water sewer.

Six off-site extraction wells are also connected with Systems 1 and 3.

During 2011, System 1 included the following extraction and treatment components:

• 14 extraction wells;

• One basement-dewatering sump conveyed to treatment system fromFairchild Building 18,

• Three 5,000-pound GAC vessels in series.

During 2011 System 3 included the following extraction and treatment components:

• Influent from twelve extraction wells;

• One pad sump, including sump pump;

• Three 5,000-pound GAC vessels in series.

In the 2011 annual monitoring event, all of the Site wells sampled had TCEconcentrations that were within or below historical ranges.

• VOC concentrations are steady to decreasing over time. TCE concentrations in a majority of the Site wells either have astable or decreasing trend over the last ten years.

Vishay GSI, SUMCO @405 National Ave

The 405 National Avenue site measures approximately 290 ft (ft) by 170 ft and is bounded to the north by NationalAvenue, to the east by 425 National Avenue, to the west by 401 National Avenue, and to thesouth by the Hetch-Hetchy Easement. In addition, there is a 10-foot-wide public utilityeasement along the southern property boundary.

Until the site was redeveloped in 2001, there was a one-story industrial building, measuringapproximately 200 ft by 100 ft. The building wasconstructed in the mid-1960s and was first occupied by Elmat Corporation from 1967 to 1969.Semimetals, a subsidiary of General Instrument Corporation (now Vishay) occupied thebuilding between 1969 and 1978. Siltec Corporation (now SUMCO Phoenix Corporation) thenpurchased the property and occupied the building from 1978 to 1987. The property was sold toUniSil Corporation (UniSil) in 1989, and UniSil occupied the building until the spring of 1999,when UniSil ceased operations at 405 National Avenue.

In 2001, the 405 and 423 National Avenue properties were redeveloped. The redevelopmentactivities included demolition of existing buildings and construction of a new two-storycommercial building, along with associated parking, drainage, and utility facilities. As part ofthat redevelopment, the 405 and 423 National Avenue properties were combined and are nowcollectively referred to as 425 National Avenue. The 425 National Avenue property completed interiorrenovation of the building in April 2008.

A slurry wall was installed at 401 National, just west of 405. The soil remedy included a soil vapor extraction system (SVE), hooked up to one vapor extraction well on the southside of the former 405 National Avenue building, and four inclined dual-purpose vapor andgroundwater extraction wells on the property boundary between the 401 and former405 National Avenue properties. Vapor extracted from these wells was piped to a vaportreatment system on 401 National Avenue and treated using granular activated carbon (GAC)beds.Following approval by theU.S. EPA, the SVE was permanently shut down on March 22, 1999.

The groundwater extraction and treatment system includes five on-site and three off-sitegroundwater extraction wells. The groundwater treatment system consists of pretreatment by an ultraviolet light-hydrogenperoxide (UV-H2O2) oxidation unit followed by final treatment through a shallow tray air stripper. Until December 2004, treated groundwater was discharged to the sanitary sewerunder a discharge permit from the City of Mountain View.

Sampling wells (2011) indicate TCE range 330 – 56,000 ppb, all generally exhibiting historical decline or stable. The total gallons of groundwater treated in 2011 are approximately 9,677,470 gallons. The totalmass of VOCs removed in 2011 isapproximately 142.6 pounds.

The groundwater extraction and treatment system is operating, and will continue to operate in conformance with the designparameters outlined in the Final Remedy. Opportunities for treatment system optimization may include: (1) implementing an optimized pumping program to remove VOCs more efficiently, and (2) in-situ remedial treatment technologies that are capable of decreasing VOC groundwater concentrations in groundwater underlying the site and/or lowering annual operating costs.

Intel @ 365 E. Middlefield

In 1981, Intel learned of chemical contamination from underground storage. It removed soil in 1984 and treated groundwater in 1982 through 2005. It removed 1,623 pounds of VOCs in the first two years, from 26 mill gallons of groundwater. Between 1986 and 2005 an additional 364 Lbs. of VOCs were removed, treating 50 million galls. TCE in B2 decreased from 15 to 0.5 ug/L. In A zone, concentrations of TCE ranged from ND (non-detect) to 900; for cis-1, 2-DCE concentrations from ND to 1000; for VC, concentrations ranged ND to 960.

Intel and Raytheon continued the in-situ bioremediation pilot test started in 2005 at 365 and 401 E. Middlefield. First phase involved emulsified oil injection (2,800 gallons) in nine locations. Second phase involved 91,000 gallons of oil injected at 40 points. Bacteria were also injected in a few of these wells. Additional activities included injecting sodium lactate and vitamin amendment in 35 new injection points, as well as bioaugmentation. After sodium lactate injection, TCE decreased dramatically in one well, although rebounded. It is thought that additional VOC mass is entering the test area. Additional electron donor injection and bioaugmentation took place between 2009 - 2010.

TCE concentrations have been significantly decreased by 96% - 99%, following electron donor injection in 2005, 2006 and 2009. In one well, TCE went from 1,400 to 8.4. Some sequential complete dechlorination was observed. The guard wells surrounding the test area were relatively stable, although some VC increases were observed.

Regional Groundwater Remedial Program (RGRP)

The VOCs addressed in the MEW ROD are assigned to both facility-specific andregional responsibilities. Each MEW Company is responsible for investigation,remediation, and source control for VOCs in soil and groundwater at their facilityspecificproperties south of Highway 101, as described above. The MEW Companies are jointlyresponsible, through the RGRP, for remediation of VOCs in groundwater that is notbeing captured by the facility-specific source control systems or that cannot beattributed to a single source (EPA, 2004).