SEMS-RM DOCID # 100038437
SIXTH FIVE-YEAR REVIEW REPORT FOR
ADVANCED MICRO DEVICES 901/902 AND TRW MICROWAVE SUPERFUND SITES
INCLUDES THE COMPANIES' "OFFSITE" OPERABLE UNIT
SANTA CLARA COUNTY, CALIFORNIA
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PREPARED BY
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Seattle District
FOR
U.S. Environmental Protection Agency
Region 9
Approved by:
MICHAEL
MONTGOMERY
Digitally signed by
MICHAEL MONTGOMERY
Date: 2024.09.27 09:41:36
-07W
Date:
Michael Montgomery, Director
Superfund and Emergency Management Division
U.S. Environmental Protection Agency,
Region 9
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Executive Summary
This is the sixth Five-Year Review of the Advanced Micro Devices 901/902 Thompson Place Site
(AMD Site), the TRW Microwave Superfund Site (TRW Site), and the Companies' "Offsite"
Operable Unit (Offsite OU), located in Sunnyvale, California. The purpose of this Five-Year
Review is to review information to determine if the remedy is and will continue to be protective
of human health and the environment.
The U. S. Environmental Protection Agency (EPA) issued a Record of Decision in 1991 that
addressed the AMD Site, the TRW Site, the Signetics Site, and the Offsite OU. These three sites
and the "offsite" operable unit have been collectively known by the informal term, "Triple Site."
Each of the three Superfund sites and their commingled plume have been considered
separately as one of four operable units within the larger study area.
EPA is the lead agency overseeing environmental investigation and remediation work at the
Triple Site. The State of California, San Francisco Bay Regional Water Quality Control Board
(Regional Water Board), was previously the lead agency. On August 7, 2014, EPA Region 9 and
the Regional Water Board agreed to transfer lead agency oversight responsibilities for the
Triple Site to EPA Region 9.
This Five-Year Review addresses the AMD Site, the TRW Site, and the Offsite OU. The Signetics
Site is not evaluated in this document because it is not listed on the National Priorities List, and
thus not required by Federal Superfund law to be included in the Five-Year Review process.
Nevertheless, information pertaining to the Signetics Site is frequently discussed in this
document because this Site is a significant contributor to the Offsite OU groundwater
contamination and its treatment system is located at the Signetics Site.
AMD 901/902 Thompson Place Site
EPA selected the following remedy for the AMD Site in the 1991 Record of Decision: soil
excavation; groundwater extraction and treatment; groundwater monitoring; and placement of
an environmental covenant prohibiting installation of onsite wells until the completion of
groundwater remediation.
Soil excavation at the AMD Site was completed in 1992. A No Further Action letter regarding
soil remediation for the site was then issued by the Regional Water Board in 2008. The
groundwater remedy as described in the 1991 Record of Decision (a groundwater extraction
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and treatment system) is no longer operating due to declining effectiveness. Portions of the
groundwater extraction and treatment system are still onsite but no longer in use. Current
activities onsite include an in-situ bioremediation treatability study program that injects
carbohydrate amendments and monitor the effects in reducing the concentration of the
chemicals of concern in groundwater. EPA will amend the remedies once vapor intrusion
investigations and Focused Feasibility Studies are completed for the Triple Site.
Annual groundwater data indicate that four chemicals of concern (trichloroethene [TCE], cis-
1,2-dichloroethene [cDCE], trans-l,2-dichloroethene [tDCE], and vinyl chloride) remain at levels
above cleanup standards at the site in the A, Bl, and B2 groundwater aquifer zones. Remedial
efforts have largely reduced concentrations in the original source areas. TCE degradation
product (cDCE and vinyl chloride) levels have increased in the in-situ bioremediation treatment
areas, indicating that degradation is occurring but that it is incomplete. Migration of
contaminants into the site from offsite sources is observed in upgradient wells.
There have been no changes to the Applicable, Relevant and Appropriate Requirements which
groundwater cleanup goals were based on. Land use has not changed since the last Five-Year
Review. Exposure pathways from soil and groundwater are being controlled. An environmental
covenant was recorded in 2005 for the AMD Site that prohibits residential land use,
groundwater well installation, and soil excavation.
The remedy at the AMD Site currently protects human health and the environment because
exposure pathways for soil and groundwater are controlled and there is no evidence of
unacceptable vapor intrusion risk for the current commercial land use. However, in order for
the remedy to be protective in the long-term, soil gas and sewer gas investigations are needed
to further evaluate site conditions, update the conceptual site model, and update the focused
feasibility study. Additionally, based on Triple Site outdoor air study findings, further
investigation is needed to evaluate if potential volatilization to outdoor air from the AMD
subsurface source is influencing the outdoor air TCE concentrations onsite. Finally, EPA should
select a revised groundwater remedy for the AMD Site, as the groundwater extraction and
treatment system, a key element of the remedy selected in the 1991 Record of Decision, is no
longer operating. The revised remedy should also address vapor intrusion in the event of future
land use changes, as vapor intrusion evaluation was limited in the 1991 ROD. Also, a new
environmental covenant should be recorded.
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TRW Microwave Site
In the 1991 Record of Decision, EPA selected the following remedy for the TRW Site:
groundwater extraction; treatment of extracted groundwater by air stripping; groundwater
monitoring; discharge of treated water under a National Pollutant Discharge Elimination System
permit; and institutional controls including a deed restriction on on-site wells.
A groundwater extraction and treatment system operated at the TRW Site between 1986 and
2001. Between 1993 and 1998, a soil vapor extraction and treatment system was used to
facilitate cleanup of residual contamination. Due to declining effectiveness, the groundwater
extraction and treatment system was discontinued in 2001. Pilot testing for enhanced
anaerobic biodegradation began in 2000 and was expanded in 2005 using Hydrogen Release
Compound™ as the substrate. Further treatment was conducted using cheese whey as the
substrate in 2007 and 2008 and using emulsified vegetable oil (EVO) and pure soybean oil in
2010. Additional injections of EVO under the building were performed in 2014. Enhanced
anaerobic biodegradation has achieved some success in reducing chemical contaminants
concentrations, although rebound has been observed.
Overall, remedial efforts have largely reduced chemical contaminant concentrations in the
source area and in the shallow aquifer zones since implementation of the remedy. Migration of
contaminants into the site is observed in upgradient and cross-gradient wells.
TRW conducted an initial vapor intrusion evaluation at the TRW Site in 2014 which indicated
that TCE concentrations in indoor air near the former source area exceeded the applicable
commercial screening levels and presented an inhalation risk. Building mitigation measures
were completed by 2015, which included sealing of floor penetrations, installing a passive sub-
slab ventilation system and modifications to the building's Heating Air Conditioning and
Ventilation (HVAC) system. Confirmatory indoor air sampling following the completion of the
mitigation measures showed levels of chemical contaminants below levels considered safe,
confirming the effectiveness of the mitigation measures in addressing the inhalation risk.
However, monitoring for long-term stewardship is required to ensure the mitigation measures
remain effective in the long-term. Additionally, exterior soil gas investigation is needed to
update the Conceptual Site Model and update the focused feasibility study for EPA to select a
revised groundwater remedy for the TRW Site.
There have been no changes to the Applicable, Relevant and Appropriate Requirements, which
groundwater cleanup goals were based on, since the Record of Decision was issued. Land use
has not changed since the last Five-Year Review. Exposure pathways for soil and groundwater
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are being controlled. A covenant and agreement that prohibits use of groundwater, restricts
excavation of soils, and prohibits residential land use was recorded in 1992.
The remedy for the TRW Site currently protects human health and the environment because
exposure pathways for soil and groundwater that could result in unacceptable risks are
prevented through a land use covenant and agreement. There is no evidence of unacceptable
vapor intrusion risk for the current commercial building on-site. However, in order for the
remedy to be protective in the long-term, EPA should select a revised groundwater remedy for
the TRW Site, as the groundwater extraction and treatment system, a key element of the
remedy selected in the 1991 Record of Decision, is no longer onsite. The revised remedy should
also address vapor intrusion in the event of future land use changes, as vapor intrusion
evaluation was limited in the 1991 ROD.
Offsite Operable Unit
The Offsite OU extends north from the Signetics Site and encompasses an area of
approximately 100 acres. The area currently includes three school campuses and more than
500 residential units. Groundwater contamination in the Offsite OU is due to commingled,
upgradient sources from Signetics, AMD and TRW Sites.
In the 1991 Record of Decision, EPA selected expanded groundwater extraction, treatment of
extracted groundwater by air stripping, and reuse or discharge of the treated groundwater to
surface water under a National Pollutant Discharge Elimination System permit.
The remedy is generally containing contaminant offsite migration. The concentration footprint
of the plume has not significantly changed within the review period, nevertheless well
COM63B1 in the north side downgradient area indicates some offsite migration in the B1
aquifer zone. Additional groundwater plume characterization activities are currently ongoing to
further evaluate and refine plume extent. Groundwater restoration within the Offsite OU has
not progressed substantially and is not expected to be achieved in a reasonable timeframe. In
addition to the groundwater plume supplemental characterization work, a treatability study of
Enhanced Anerobic Bioremediation at the source zone on the Signetics Site is currently
ongoing.
There have been no changes to the Applicable, Relevant and Appropriate Requirements which
groundwater cleanup goals were based on since the 1991 Record of Decision. Land use is
primarily residential. Institutional controls are in place to prevent private well installation in
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Santa Clara County, and a municipal water supply exists for the area (Hetch Hetchy Reservoir in
the Sierra Nevada Mountains).
An ongoing vapor intrusion assessment and mitigation in the Offsite OU began in 2015.
Mitigation efforts have largely consisted of installation of sub-slab or submembrane
depressurization systems, and Operations & Maintenance activities. Over 4,900 air samples
have been collected to date. A total of 237 residential units and 126 school classrooms were
sampled. Mitigation systems were installed in 13 residential units and 12 school buildings.
Currently, about 58 buildings didn't allow access for sampling. Obtaining access to residential
properties to conduct indoor air sampling remains a challenge in the Offsite OU. EPA is
increasing community involvement efforts to encourage property owners to provide access.
The remedy for the Offsite Operable Unit currently protects human health and the environment
because there are no direct exposures to groundwater, and the vapor intrusion pathway is
being controlled through investigation of indoor air and installation of mitigation measures
where necessary and where access has been granted. However, in order for the remedy to be
protective in the long-term, a revised remedy is needed to achieve the RAOs in reasonable time
and to ensure the long-term stewardship of the vapor intrusion mitigation measures currently
in place. For EPA to select a revised remedy, a focused feasibility study that incorporates an
updated conceptual site model with information from appropriate exterior soil gas and sewer
gas investigation is needed. Finally, based on Triple Site outdoor air study findings, further
investigation is needed to evaluate if potential volatilization to outdoor air from Triple Site
subsurface sources (e.g., areas with higher TCE concentrations in the A aquifer zone) is
influencing the outdoor air TCE concentrations onsite.
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Contents
Executive Summary ii
List of Figures viii
List of Tables viii
List of Acronyms and Abbreviations x
1. Introduction 12
1.1. Background 13
1.2. Physical Characteristics 17
1.3. Hydrology 21
2. Remedial Actions Summary 23
2.1. Basis for Taking Action 23
2.2. Remedy Selection 24
2.3. Remedy Implementation 26
3. Progress Since the Last Five-Year Review 30
3.1. Previous Five-Year Review Protectiveness Statement and Issues 30
3.3. Work Performed During this Five-Year Review Period 34
3.3.1. AMD 901/902 Thompson Place Site 34
3.3.2. TRW Microwave Site 34
3.3.3. Signetics Site and Offsite Operable Unit 35
4. Five-Year Review Process 36
4.1. Community Notification, Involvement and Site Interviews 36
4.1.1. Five-Year Review Press Release 36
4.1.2. Site Interviews 36
4.2. Data Review 37
4.2.1. Groundwater 37
4.2.2. Vapor Intrusion 42
4.2.3. Climate Resilience Screening 45
4.3. Site Inspection 45
5. Technical Assessment 46
5.1. Question A: Is the remedy functioning as intended by the decision documents? 46
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5.2. Question B: Are the exposure assumptions, Toxicity Data, Cleanup Levels, and Remedial
Action Objectives Used at the Time of Remedy Selection Still Valid? 46
5.3. Question C: Has Any Other Information Come to Light That Could Call Into Question the
Protectiveness of the Remedy? 47
6. Issues/Recommendations 47
6.1. Other Findings 51
7. Protectiveness Statement 53
8. Next Review 54
Appendix A: List of Documents Reviewed 55
Appendix B: Data Review 58
Appendix C: Applicable or Relevant and Appropriate Requirements Assessment 103
Appendix D: Public Notice 107
Appendix E: Interview Forms Ill
Appendix F: Site Inspection Report and Photos 130
List of Figures
Figure 1. Location Map for the AMD 901/902 Site, TRW Microwave Site and Offsite OU 17
Figure 2. Detailed Map of the AMD 901/902 Site, TRW Microwave Site and Offsite OU 20
Figure 3. Cross-Section Showing hydrostratigraphic units in the A, Bl, and B2 Zones beneath
the TRW Site 23
Figure 4. Some Upgradient TCE Sites from the GEOTRACKER Database 52
List of Tables
Table 1. Five-Year Review Summary Form 13
Table 2. Aquifer designations with associated water bearing zones and Hydrostratigraphic
Units 21
Table 3. Groundwater Cleanup Levels from 1991 ROD 24
Table 4: Status of Recommendations from the 2019 Five-Year Review 32
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Table 5. AMD Groundwater Concentration Data 38
Table 6. TRW Groundwater Concentrations Trends 39
Table 7. Linear projections for 00U to Reach ROD Remediation Levels for TCE 41
Table 8. Offsite Operable Unit Groundwater Concentration Trends 41
Table 9. Issues and Recommendations Identified in the Five-Year Review 47
Table 10. Protectiveness Statement 53
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List of Acronyms and Abbreviations
1.1-DCA 1,1-dichloroethane
1.2-DCB 1,2-dichlorobenzene
1,1-DCE 1,1-dichloroethylene
1,1,1-TCA 1,1,1-trichloroethane
AOC Administrative Order on Consent
AMD Advanced Micro Devices
ARAR applicable or relevant and appropriate requirements
cDCE cis-l,2-dichloroethylene
CSM Conceptual Site Model
DNAPL Dense non-aqueous phase liquid
EAB enhanced anaerobic biodegradation
EPA U.S. Environmental Protection Agency
ESS Environmental sequence stratigraphy
FFS Focused Feasibility Study
GWETS groundwater extraction and treatment system
HRC hydrogen release compound
HSU hydrostratigraphic unit
HVAC heating and ventilation systems
ISB in-situ bioremediation
MCE Microbial Chain Elongation
MCL maximum contaminant limit
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NPDES National Pollutant Discharge Elimination System
NPL National Priorities List
OU operable unit
PCE tetrachloroethylene
PRP Potentially Responsible Party
RAO remedial action objectives
Regional Water The State of California, San Francisco Bay Regional Water Quality
Board Control Board
ROD Record of Decision
RSL regional screening level
SCVWD Santa Clara Valley Water District
TCE trichloroethylene
tDCE trans-l,2-dichloroethylene
Triple Site AMD 901/902 Site, TRW Microwave Site and Offsite Operable Unit
USACE United States Army Corps of Engineers
UST underground storage tank
UV ultraviolet
VOC volatile organic compounds
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1. Introduction
The purpose of a Five-Year Review is to evaluate the implementation and performance of a
remedy in order to determine if the remedy will continue to be protective of human health and
the environment. The methods, findings, and conclusions of reviews are documented in Five-
Year Review reports. In addition, Five-Year Review reports identify issues found during the
review, if any, and document recommendations to address them.
EPA is preparing this five-year review pursuant to the Comprehensive Environmental Response,
Compensation, and Liability Act Section 121, 40 Code of Federal Regulation Section
300.430(f)(4)(ii) of the National Contingency Plan and EPA policy.
This is the sixth Five-Year Review for the AMD Site, TRW Site, and the Offsite OU. The triggering
action for this statutory review is the completion of the previous Five-Year Review on
September 18, 2019. The Five-Year Review has been prepared because hazardous substances,
pollutants, or contaminants remain at the Site above levels that allow for unlimited use and
unrestricted exposure.
This Five-Year Review was led by Dr. Lilian Abreu, EPA Region 9 Remedial Project Manager.
Participants included Cynthia Ruelas, EPA Region 9 Superfund Five-Year Review Coordinator
and from the United States Army Corps of Engineers (USACE): Jacob Williams, Program
Manager, Rebecca Rule, USACE Project Manager, Benino McKenna, USACE Geologist, Ashley
Provow, USACE Geologist, Matthew Wetter, USACE Environmental Engineer and Cody Davis,
USACE Engineer. The review began on October 18, 2023. The documents reviewed are listed in
Appendix A.
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le 1. Five-Year Review
SITE IDENTIFICATION
Site Name: Advanced Micro Devices 901/902 and TRW Microwave Superfund Sites
EPA ID:
CAD048634059 (AMD) and CAD009159088 (TRW)
Region: 9
State: CA
City/County: Sunnyvale, Santa Clara County
National Priorities List Status: Final
Multiple Operable Units? Yes
Has the site achieved construction completion? Yes
Lead agency: EPA
[If "Other Federal Agency", enter Agency name]:
Author name (Federal or State Project Manager): Dr. Lilian Abreu
Author affiliation: USEPA Region 9
Review period: 10/18/2023 - 6/17/2024
Date of site inspection: 3/5/2024
Type of review: Statutory
Review number: 6
Triggering action date: 9/18/2019
Due date (five years after triggering action date): 9/18/2024
1.1. Background
The AMD Site, TRW Site, Signetics Site and Offsite OU are clustered together on relatively flat
land south of San Francisco Bay in Sunnyvale, California (Figure 1). These three Sites and the
Offsite OU are collectively known by the informal term, "Triple Site." Each of these three
Superfund sites and their commingled "offsite" plume have been considered separately as one
of four operable units within the larger study area. The operable units reviewed for this Five-
Year Review are the AMD Site, TRW Site, and Offsite OU.
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The Signetics Site is not evaluated in this Five-Year Review because it is not listed on the
National Priorities List (NPL), and thus not required by Federal Superfund law to be included in
the Five-Year Review process. The Signetics Site was proposed for listing on the NPL but was
ultimately not listed because it was being regulated under a different Federal program, the
state-authorized Resource Conservation and Recovery Act program. Nevertheless, information
pertaining to the Signetics Site is frequently discussed in this document because this Site is a
significant contributor to the Offsite OU groundwater contamination and because the
treatment system for the Offsite OU is located at the Signetics Site.
On August 7, 2014, EPA Region 9 and the Regional Water Board agreed to transfer lead agency
oversight responsibilities for the Triple Site (AMD Site, TRW Site, Signetics Site, and the Offsite
OU) from the Regional Water Board to EPA Region 9.
AMD 901/902 Thompson Place Site
The AMD Site boundary, as defined in the 1991 Record of Decision (ROD), includes the location
of two former large, low-rise industrial buildings connected by a hallway (formerly 901 and 902
Thompson Place) and extends east to DeGuigne Drive. As defined, the AMD Site includes seven
other commercial buildings. However, these seven buildings do not overlie groundwater
impacted by former AMD operations.
AMD manufactured printed circuit boards and semiconductors continuously at the AMD Site
between 1969 and 1992. During this time, AMD used TCE and other industrial solvents for
cleaning and degreasing. TCE use reportedly ceased around 1979. Acids were used for etching
and caustics were used for acid neutralization. Acid neutralization systems, including in-ground
sumps, were used at both AMD buildings between 1969 and 1984. Related hazardous wastes
generated from these various operations were stored on-site.
In 1982, leakage from an acid neutralization sump at the former 901 Thompson Place building
initiated site investigations. The sump in the former 902 Thompson Place building was
subsequently found to also be leaking. Additional studies of groundwater contamination in the
1980s identified chlorinated volatile organic compounds (VOCs), primarily TCE and its
biodegradation products, cDCE and vinyl chloride, in the upper 65 feet of soil under the AMD
Site.
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TRW Microwave Site
The former TRW Microwave Site is located to the north of the AMD Site, also in a
topographically flat area of the Santa Clara Valley. The onsite building has been vacant since
January 2001. Between 2001 and 2003, a portion of the building was demolished and a new
structure, contiguous with the remaining portion of the existing building, was constructed.
TRW assembled and tested microwave and semiconductor components at the TRW Site
between 1968 and 1993. TRW used TCE and several other industrial solvents and hazardous
compounds; hazardous wastes were generated as a by-product of the operations. TRW stored
waste solvents (mostly TCE) in an underground storage tank from 1970 through 1982. The tank
was removed in early 1983. An in-ground, three-stage, ammonia gas acid neutralization system
also operated from 1968 to 1984, when it was disconnected and removed. It was replaced by
an aboveground system with secondary containment. The aboveground acid neutralization
system was disconnected and removed in 2001, during remodeling of the site building.
TRW initiated an investigation of potential impacts to soil and groundwater at the TRW Site
following the removal of the underground storage tank. Between 1983 and 1986, several
subsurface investigations were conducted in the vicinity of the former areas of the
underground storage tank, the acid neutralization systems, and associated piping. The
investigations identified VOCs as the only contaminants of concern at the TRW Site, and the
former underground storage tank area as the only source of VOCs impacting groundwater at
the TRW Site.
Offsite Operable Unit
The Offsite OU extends north from the AMD and TRW Sites and represents the largest OU in
spatial extent. The Offsite OU was originally mapped to encompass a single commingled
groundwater contaminant plume composed primarily of dissolved TCE.
In the 1980s, investigations began in the groundwater north of Duane Avenue to provide
information on the vertical and horizontal extent of contamination in the Offsite OU.
Contaminants were discovered in groundwater but were not observed in the soil in the Offsite
OU. Due to the lack of potential sources in the Offsite OU, the sources for the observed
contaminant concentrations were attributed to the AMD, TRW, and Signetics Sites located up-
gradient of the area. A commingled plume of contaminated groundwater, approximately 4,000
feet long, underlies the land in the Offsite OU and extends beyond U.S. Highway 101 to the
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north. Chemical contaminants in the groundwater plume are primarily chlorinated VOCs,
predominantly TCE.
The Offsite OU encompasses an area of about 100 acres. The area currently includes three
school campuses and more than 500 residential building units. The school campuses include a
child development center, one elementary school, and one middle/high school. The
groundwater plume in this operable unit is currently under ongoing additional investigation for
refined characterization.
In 2015, EPA entered into an enforcement agreement with Philips Semiconductors, Inc. (Philips)
for the Offsite OU, to assess and mitigate, as necessary, indoor air quality in buildings that may
be at risk from solvent vapors rising from the contaminated groundwater and accumulating
indoors at unacceptable levels (a process called "vapor intrusion"). After this original
agreement expired, a new enforcement agreement was signed in 2019.
An ongoing vapor intrusion assessment and mitigation in the Offsite OU began in 2015.
Mitigation efforts have largely consisted of installation of sub-slab or submembrane
depressurization systems, and Operations & Maintenance activities. Over 4,900 air samples
have been collected to date. A total of 237 residential units and 126 school classrooms were
sampled. Mitigation systems were installed in 13 residential units and 12 school buildings.
Currently, about 58 buildings have not allowed access for sampling. Obtaining access to
residential properties to conduct indoor air sampling remains a challenge in the Offsite OU. EPA
is increasing community involvement efforts to encourage property owners to provide access.
Related Site - Signetics Site
The Signetics Site is a significant contributor to Offsite OU groundwater contamination, and it is
the location of the Offsite OU's treatment system. In 2019, EPA entered into an enforcement
agreement with Philips for the Signetics Site, which requires the company to conduct a focused
feasibility study to evaluate options for accelerating the groundwater cleanup at the Signetics
Site. The enforcement agreement further requires Philips to assess and mitigate, as necessary,
vapor intrusion in commercial buildings at the Signetics Site. Additionally, the agreement
includes a requirement for a treatability study to evaluate the potential for in-situ
bioremediation (ISB) to accelerate the pace of the groundwater cleanup and ultimately reduce
the potential vapor intrusion risks to the surrounding community.
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Figure 1. Location Map for the AMD 901/902 Site, TRW Microwave Site and
Offsite OU
1.2. Physical Characteristics
AMD 901/902 Thompson Place Site
The AMD Site is located in the southeastern corner of the Triple Site and borders the Signetics
Site (Figure 2). Prior to the late 1960S; land use in Santa Clara County was agricultural,
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predominantly commercial fruit orchards. Industrial operations began at the AMD Site in 1969
when AMD began manufacturing printed circuit boards and semiconductors at 901 Thompson
Place. AMD began operations at the former 902 Thompson Place building in 1972, operating
the combined facility until 1992. Operations were continuous with no significant process
changes until 1992.
AMD discontinued operations and vacated the two buildings in 1992. The AMD Site was sold to
Westcore Thompson II, LLC in 2005 and later transferred to Summit Commercial Properties, Inc.
Summit demolished the two buildings in 2006 and built a self-storage warehouse in 2007. The
address was also changed from 901/902 Thompson Place to 875 East Arques Avenue at that
time.
The AMD Site boundary, as defined in the ROD, includes the location of the two former low-rise
industrial buildings connected by a hallway (formerly 901 and 902 Thompson Place) and
extends east to DeGuigne Drive (Figure 2). As defined, the east side of AMD Site includes seven
other commercial buildings. However, these seven buildings do not overlie groundwater
impacted by former AMD operations. Groundwater on the east side of the property is
potentially impacted by contaminant migration from off-site, up-gradient sources. Theself-
storage warehouse built in 2007 currently occupies the former footprint of the 901 and 902
Thompson Place buildings. The area immediately surrounding the property is a mix of light
commercial use and residential properties.
TRW Microwave Site
The TRW Site is located to the north of the AMD Site and borders the Signetics Site and the
Offsite OU (Figure 2). Industrial operations began at the TRW Site in 1968, when Aertech
Industries began assembling and testing microwave and semiconductor components. In 1974,
TRW acquired the site from Aertech and continued similar operations. In 1987, FEI Microwave
purchased the site from TRW. FEI Microwave operated the facility until 1993. FEI Microwave
subsequently became Tech Facility 1, Inc. Operations were continuous with no significant
process changes between 1968 and 1993. In 1995 the TRW Site was acquired by Stewart
Associates and subsequently leased to Diablo Research Corporation and Cadence Inc. for
research and development operations.
In 2002, TRW merged with Northrop Grumman Systems Corporation (Northrop Grumman). In
2004, the property was purchased by Pacific Landmark. The property ownership changed again
in May 2014 to Hines. During these changes in ownership of the TRW Site, TRW and then
Northrop Grumman retained responsibility for the site cleanup. The building is currently
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occupied and is zoned for light industrial use. The area immediately surrounding the property is
light commercial with a mix of residential properties.
Offsite Operable Unit
The Offsite OU is located in the northern area of the Triple Site (Figure 2). It is primarily a
residential neighborhood consisting of single-family and multi-family homes and currently
includes three school campuses. None of the Offsite OU-properties are related to the former
Companies (AMD, TRW, and Signetics/Philips) or their environmental impacts via their
industrial operations. Directly to the north and downgradient of the Signetics, AMD, and TRW
Sites is the former high school for the City of Sunnyvale, which was used until the early 1980s.
Subsequently, the school was leased for several years to house an engineering center.
Currently, the buildings at the 790 and 794 East Duane Avenue properties are occupied by a
child development center and a middle-high school campus, and an elementary school is at the
approximate center of the Offsite OU.
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Figure 2. Detailed Map of the AMD 901/902 Site, TRW Microwave Site and
Offsite OU
20 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
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1,3, Hydrology
The AMD and TRW Sites and the Offsite OU are located in the Santa Clara Valley, a structural
basin bounded by the Santa Cruz Mountain to the south and west, and the Diablo Range to the
north. The sites are underlain by alluvial sequences eroded from the Santa Cruz Mountains and
deposited in the basin in north-trending streams leading to San Francisco Bay. The depositional
environment is characterized by meandering and braided stream systems that created
sequences of coarse-grained units interbedded with fine-grained clay and silt.
The alluvial sediments at the sites are divided into two hydrogeologic zones referred to as the
Upper Aquifer and the Lower Aquifer (Table 2). These two zones are separated by a relatively
impermeable aquitard at approximately 120 feet below ground surface. The Lower Aquifer, an
extensive, deep, regional, confined aquifer, lies underneath the aquitard. Municipalities utilize
some wells within this deep regional aquifer for drinking water. However, the Santa Clara Valley
Water District supplies drinking water for this part of Sunnyvale from the Hetch Hetchy
Reservoir in the Sierra Nevada Mountains and tests the supply to ensure that all state and
Federal drinking water standards are met.
Table , designations with associated water bearing ion I
Hydrostratigraphic Units,
Regional Designation
Local Zone
Designation
Approximate depth below ground surface (ft)
HSU Identified
A
20
TRW HSU 1-3
B1
40
B2
Upper Aquifer
60
B3
80
84
100
B5
Regional Aquitard
B-C Aquitard
120
Lower Aquifer
C Aquifer
300
500
Source: USEPA 2019. Fifth Five-Year Review Report for Advanced Micro Devices 901/902 and TRW Microwave Superfund Sites,
Includes the Companies' Offsite Operable Unit, Santa Clara County, California
Note: Hydrostratigraphic units (HSU) consist of very permeable coarse-grained material inferred to be relic channel
deposits that generally trend north/south. These channel deposits are surrounded by low-permeability silts and clay inferred to
be overbank stream deposits. The channel deposits provide preferred pathways for contaminant migration hydraulically
downgradient from the source area.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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The Upper Aquifer is divided into six water-bearing zones, Zone A, and Zones B1 through B5
(Table 2). The Upper Aquifer consists of transmissive sand and gravel units vertically and
laterally separated by low permeability units of silt and/or clay. Groundwater flow direction for
all upper zones is generally to the north, toward San Francisco Bay. Groundwater extraction
wells within the Upper Aquifer in the Offsite OU and at adjacent sites impact local groundwater
direction and gradient.
The water-bearing zones appear to be laterally continuous throughout the AMD and TRW Sites
and Offsite OU and range from silty sand to sand and gravel. Several higher permeable units
within a single water-bearing zone were identified. Each zone has a heterogeneous composition
and contains lenses that are highly discontinuous and more permeable than surrounding soil.
Northup Grumman, the company responsible for the TRW Site, has detailed the depositional
environment of alluvial deposits in the Triple Site area. Numerous hydrostratigraphic units were
identified within A, Bl, and B2 Zones (Figure 3). These hydrostratigraphic units have not been
projected or identified to any significant extent beyond the TRW Site. Permeable channel
deposits representing hydrostratigraphic unit preferred pathways have been identified in the A
and Bl Zones at the adjacent Signetics Site.
22 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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Source: AECOM 2017. Well Installation Work Plan, Former TRW Microwave Site, 825 Stewart Drive, Sunnyvale,
California
Figure 3. Cross-Section Showing hydrostratigraphic units in the A, Bl, and B2
Zones beneath the TRW Site
2. Remedial Actions Summary
2.1. Basis for Taking Action
The primary coritaminarit(s) of concern for the combined sites are chlorinated VOCs in soil
(AMD 901/902 and TRW Sites) and groundwater (AMD 901/902 and TRW Sites, and the Offsite
OU). The ROD identified the following ten chemicals of concern (COCs):
• 1,2-Dichlorobenzene (1,2-DCB)
• 1,1-Dichloroethane (1,1-DCA)
• 1,1-Dichloroethylene (1,1-DCE)
• Cis-l,2-Dichloroethylene (cis-l,2-DCE)
• Trans-l,2-Dichloroethylene (trans-l,2-DCE)
• Freon 113
• Tetrachloroethylene (PCE)
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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• 1,1,1-Trichloroethane (1,1,1-TCA)
• Trichloroethylene (TCE)
• Vinyl chloride
The presence of these contaminants in soil and groundwater provided the basis for taking
action under Comprehensive Environmental Response, Compensation and Liability Act. The
release of hazardous substances into the environment at the sites posed, or potentially posed,
a threat to human health and the environment via inhalation, ingestion, and direct contact.
2.2. i eel j/ Selection
The combined ROD for the Triple Site (AMD 901/902, Signetics, TRW, and Offsite OU) was
signed on September 11, 1991.
The ROD identified ten COCs in groundwater, all of which apply to the AMD 901/902 and TRW
Sites, and a subset of which are applicable to the Offsite OU.
The ROD selected state Maximum Contaminant Levels (MCLs) for groundwater cleanup
standards for nine of the ten COCs. Due to the lack of a state MCL, the cleanup level for 1,2-DCB
was set at the Federal MCL (Table 3).
No soil cleanup levels were selected in the ROD.
Remedial Action Objectives stated in the ROD are:
• Prevention of the near-term and future exposure of human receptors to contaminated
groundwater and soil
• Restoration of the contaminated groundwater for future use as a potential source of
drinking water
• Control of contaminant migration
• Monitoring of contaminant concentrations in groundwater to observe the control of
contaminant migration and the progress of cleanup
Table . water Clean rels 1 1 D
Chemical
Cleanup Levels (|ig/L)
Basis for Cleanup Level1
1,1-DCA
5
California (CA) MCL
1,2-DCB
600
Federal MCL
Cis-1,2-DCE
6
CA MCL
Trans-1,2-DCE
10
CA MCL
24 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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Chemical
Cleanup Levels (|ig/L)
Basis for Cleanup Level1
1,1-DCE
6
CAMCL
Freon 113
1200
CAMCL
PCE
5
CAMCL
TCE
5
CAMCL
i,i,i-tca
200
CAMCL
Vinyl Chloride
0.5
CAMCL
1 The more stringent of the Federal or State drinking water standard was selected as the basis for the groundwater
cleanup level.
AMD 901/902
The remedy selected in the ROD for the AMD 901/902 Site consists of the following elements:
• Soil excavation followed by off-site incineration/disposal of the remaining contaminated
soil beneath the AMD 901/902 Site
• Continued groundwater extraction and treatment by air stripping
• Discharge of treated water under a National Pollutant Discharge Elimination System
(NPDES) permit
• Groundwater monitoring
• Placement of a restrictive covenant prohibiting installation of onsite wells until
groundwater remediation is completed and well permit requirements
TRW
The remedy selected in the ROD for the TRW Site consists of the following elements:
• Groundwater extraction
• Treatment of extracted groundwater by air stripping
• Discharge of treated water under a National Pollutant Discharge Elimination System
(NPDES) permit
• Groundwater monitoring
• Institutional controls, including restrictions on groundwater extraction and well permit
requirements
Offsite OU
The remedy selected in the ROD for the Offsite OU consists of the following:
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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• Expanded groundwater extraction
• Treatment of extracted groundwater by air stripping (at the time at the nearby adjacent
AMD 915 DeGuigne Drive Superfund Site, since relocated to the Signetics Site at 813
Stewart Drive)
• Reuse or discharge of the treated groundwater to surface water under a NPDES permit
2,3. lecf ementation
AMD 901/902 Thompson Place Site
In response to the 1991 Site Cleanup Requirements and ROD, an additional 94 cubic yards of
soil were excavated from the AMD Site in 1992. The contaminated soil was disposed off-site,
and the remaining uncontaminated soil was used as backfill. The Regional Water Board
reviewed the relevant soil and groundwater sampling results for VOCs and issued a No Further
Action letter, dated May 14, 2008, to confirm completion of site investigation and remedial
actions for releases with respect to unsaturated zone (shallow) soil at the AMD Site. Foundation
demolition work occurred at the AMD Site on July 27, 2016, and crews encountered residual
impacted soil during deep earthwork. Approximately 580 cubic yards of soil were excavated
and disposed off-site.
The groundwater extraction and treatment system (GWETS) began operation in 1983 with
three extraction wells. It was expanded to a total of eight extraction wells in 1993 (wells DW-1
through DW-8), and continued operation through 2002. The GWETS pumped water from the A,
Bl, and B2 zones to an onsite treatment system where VOCs were removed from the extracted
water by air-stripping. Treated water was discharged under a NPDES permit to the storm sewer
or put to reuse onsite.
The decline in effectiveness of the selected remedy (GWETS) prompted in-situ bioremediation
(ISB) to be tested to accelerate the groundwater cleanup. Pilot testing for ISB began in 2002,
and full-scale ISB commenced in 2005. During the pilot study, in which carbohydrate was
injected into the groundwater to stimulate microbial processes, TCE, cDCE, and vinyl chloride
concentrations were reduced in the pilot test wells by over 90 percent within six months.
Following the successful demonstration of the ISB pilot test, AMD expanded the ISB treatability
study program. ISB activities are currently ongoing but the GWETs required by the 1991 ROD
are no longer in use nor operational.
An environmental covenant prohibiting residential land use, groundwater well installation, and
soil excavation was recorded for the AMD Site in 2005.
26 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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In September 2013, a revised Focused Feasibility Study was submitted to EPA for review. That
FFS evaluated groundwater extraction and treatment, ISB, monitored natural attenuation, and
a permeable reactive barrier as potential revised remedies for the site. EPA is currently
reviewing the Focused Feasibility Study report and the ISB treatability study submittals.
TRW Microwave Site
Interim actions at the TRW Site began in 1983 with the removal of the waste solvent
Underground Storage Tank and associated contaminated soil. Additional soil, ultimately totaling
120 cubic yards, was removed from this area in 1984 and backfilled with pea gravel. Due to the
proximity of the excavation to the foundation of the 825 Stewart Building, not all of the
contaminated soil could be removed.
The GWETS and groundwater monitoring program at the TRW Site were fully implemented at
the time the final Site cleanup Requirements and ROD were adopted and signed in 1991.
Following the signing of the ROD, TRW began soil vapor extraction and treatment in July 1993
to enhance cleanup in the unsaturated zone in the vicinity of the former underground storage
tank area. The soil vapor extraction and treatment system operated full-time through
November 1996 and removed approximately 140 pounds of TCE. The system was removed in
November 1998 and the Regional Water Board issued a letter stating that no further action was
required in the vadose zone.
Decreases in TCE groundwater concentrations were most dramatic during the first five years of
GWETS operation (1985 to 1990). During the 1990s, TCE concentrations appeared to have
reached near-asymptotic levels. In 1998, TRW concluded that the GWETS had reached its limit
of effectiveness due to the limited ability of the GWETS to flush out chemical contaminants in
the silty/clayey zones of the aquifer system. By 2000, the TCE mass removed was only 30
percent of that removed in 1985. In 2001, the Regional Water Board approved permanent
suspension of groundwater extraction.
The GWETS was shut down in the source area in October 2000 to allow an enhanced anaerobic
biodegradation (EAB) treatability study. The study addressed high concentrations of chemical
contaminants in groundwater near the on-site source area outside of the 1984 excavation.
Complete GWETS shutdown occurred in April 2001 with the approval of the Regional Water
Board.
At the request of the current property owner, the above-ground GWETS components were
dismantled and removed in November 2012. The eight wells originally designed for use in the
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GWETS remain in use for groundwater monitoring. Currently, annual water level measurements
are made at 41 onsite monitoring wells and annual groundwater sampling occurs at 32 onsite
monitoring wells.
The EAB treatment utilized an injection of Hydrogen Release Compound into source area B1
zone wells. A follow-up injection into A zone and additional B1 zone wells occurred in June
2001. Following a successful pilot program, the EAB program was expanded in 2005 to include
the area immediately downgradient of the former source area. Between 2007 and 2008,
emulsified vegetable oil and neat vegetable oil were injected into source area wells to generate
reducing conditions and to sequester chlorinated VOCs within the neat oil. Following the
injections, two additional carbon substrates were injected down-gradient of the former site
source area in November 2011.
A Focused Feasibility Study was submitted to the Water Board and EPA in May 2011 but was
never finalized because additional investigation was ongoing at the time. The Focused
Feasibility Study is currently being evaluated by EPA to determine the next steps and
incorporation of the vapor intrusion pathway.
In October and November 2014, an opportunity arose to excavate additional contaminated
soils from the source area during property redevelopment. A targeted excavation was
conducted, during which approximately 485 cubic yards of soil and semi-solids were removed
from the source area. Some soils beneath the slab were solidified at that time and EVO was
injected into soils that could not be removed to enhance bioremediation.
Extraction wells were generally installed near the down-gradient site boundary to reduce the
potential to impact down-gradient properties. Injection wells were generally installed up-
gradient of the former chemical contaminant source area. Annual groundwater monitoring
activities continue at the TRW Site downgradient of the building. Monitoring of the
performance of the enhanced bioremediation zone beneath the building was not performed
due to access limitations.
Confirmatory vapor intrusion investigations were conducted in May of 2023 and January of
2024. Subslab soil gas, indoor air, and outdoor air samples were collected. Although subslab soil
gas results were above screening levels for TCE in some subslab locations, the indoor air sample
results indicated no TCE detections above reporting limits which are below EPA health
protective screening levels. Currently, a sampling plan to characterize the exterior soil gas
onsite is being prepared.
28 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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Offsite OU
Twenty-nine extraction wells are operating within the Offsite OU. The wells are clustered into
four parallel groups, based on location (Appendix B). From south to north, the well groupings
are Duane Avenue, Carmel Avenue, Alvarado Avenue, and Ahwanee Drive. The Duane Avenue
extraction well cluster includes nine extraction wells with at least one well in each of the Upper
Aquifer A, Bl, B2, B3, and B4 zones. This portion of the GWETS began pumping in November
1986. To the north of the Duane Avenue group lies the Carmel Avenue subsystem, which was
installed in 1988 and augmented in 1992. The Carmel Avenue group includes five wells
distributed among the A, Bl, and B2 zones. The Alvarado Avenue subsystem consists of 10 wells
across the A, Bl, and B2 zones. These wells were installed in 1988 and 1992. The fourth and
northernmost line of extraction wells lies along Ahwanee Drive and consists of five wells in the
A, Bl, and B2 zones. These wells were also installed in 1988 and 1992.
Until October 2010, groundwater from all the Offsite OU extraction wells was conveyed to a
treatment system located on the northern side of the adjacent AMD 915 Site. The influent
groundwater at this facility was first treated using two packed tower air stripper units plumbed
in parallel. In October 2010, groundwater extracted from the Offsite OU was permanently
diverted to the treatment system at the Signetics Site at 813 Stewart Drive. This system also
treats groundwater extracted from the Signetics Site.
The treatment system at the Signetics Site uses an ultraviolet oxidation system as the primary
treatment method. The system is sized to remove 100 percent of the influent concentrations of
Signetics and Offsite OU chemical contaminants. The ultraviolet oxidation system is also
partially effective at removing Freon 113. A secondary treatment process of air stripping follows
the ultraviolet oxidation system. The exhaust from the air stripper is vented to the atmosphere.
After these two processes, the treated effluent is discharged to the Sunnyvale East Drainage
Channel in accordance with a NPDES permit.
Institutional Controls at the Sites
The ROD provides that institutional controls in the form of deed and well-permit restrictions
will be used to protect people from exposure to contaminated groundwater below the AMD,
Signetics, and TRW properties during the cleanup period. The remedy for the AMD Site also
specifically mentions the placement of a restrictive covenant prohibiting the installation of
onsite wells until groundwater remediation is completed.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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At the AMD Site, an environmental covenant recorded in Santa Clara County on May 20, 2005,
prohibits the installation of drinking water wells on the property and restricts soil excavation. It
also prohibits residential development and construction or use of medical facilities, day-care
centers, or schools. This environmental covenant does not comply with California Civil Code
Section 1471 and will require updating once a revised remedy is selected.
An environmental covenant was recorded for the TRW Site on August 20,1992. Among other
provisions, it prohibits the drilling of drinking water wells without the approval of the Regional
Water Board.
The remedy selected in the ROD does not call for institutional controls at the Offsite OU. The
ROD mentions only deed and well permit restrictions in relation to the AMD, Signetics, and
TRW Microwave properties. Nevertheless, the Santa Clara Valley Water District (SCVWD)
regulates the construction, destruction, and maintenance of wells in Santa Clara County under
Ordinance 90-1. Well installations are prohibited without a permit from the SCVWD. This
permitting program restricts the installation of drinking water wells in the Offsite OU and also
applies to the AMD and TRW Sites.
3. Progress Since the Last Five-Year Review
Previous Five- lew Protectiveness Stateme 11ssues
The protectiveness statement from the 2019 Five-Year Review for the Advanced Micro Devices
901/902 and TRW Microwave Superfund Sites stated the following:
For the AMD Site:
The remedy at the AMD Site currently protects human health and the environment because
exposure pathways for soil and groundwater are being controlled and there is no evidence of
unacceptable vapor intrusion for the current commercial land use. However, in order for the
remedy to be protective in the long-term, a revised final groundwater remedy for the AMD Site
should be selected, as the remedy selected in the 1991 ROD is no longer operating. The revised
remedy should also address potential vapor intrusion in the event of future land use changes, as
vapor intrusion was not addressed in the 1991 ROD and record a new environmental covenant.
30 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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For the TRW Microwave Site:
The remedy for the TRW Site currently protects human health and the environment because
exposure pathways for soil and groundwater are being controlled. Exposure pathways to
contaminated groundwater that could result in unacceptable risks are prevented through a
covenant and agreement. The risk due to vapor intrusion for the current commercial land use
has been addressed. However, in order for the remedy to be protective in the long-term, a
revised soil and groundwater remedy for the TRW Site should be selected, as the remedy
selected in the ROD is no longer operating. The revised remedy should also address vapor
intrusion assessment and response procedures to ensure the long-term stewardship of the vapor
intrusion mitigation measures currently in place, as well as potential vapor intrusion in the event
of future land use changes, as vapor intrusion was not addressed in the 1991 ROD.
For the Offsite OU Site:
The remedy for the Offsite Operable Unit currently protects human health and the environment
because exposure pathways for soil and groundwater are being controlled. The risk due to vapor
intrusion for the current residential use is being addressed through installation of mitigation
measures. However, in order for the remedy to be protective in the long-term, a remedy
performance optimization and updated site conceptual model is needed. A revised remedy is
needed to achieve the RAOs and to address vapor intrusion assessment and response
procedures to ensure the long-term stewardship of the vapor intrusion mitigation measures
currently in place. Finally, an investigation of the contributions to outdoor air TCE levels from
fugitive emissions from the groundwater treatment system and emissions from the vapor
intrusion mitigation systems is needed.
The 2019 Five-Year Review included five issues and recommendations. Each recommendation
and the current status are discussed in Table 4 below.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
31
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Table 4: Status of Recommendations from the 2019 Five-Year Review
OU#
Issue
Recommendations
Cu rrent
Status
Current Implementation Status Description
Completion
Date
(if applicable)
AMD
Site
The remedy selected for
the AMD Site is no
longer being operated
and does not address
vapor intrusion.
Select a revised remedy
which also addresses
potential vapor intrusion in
the event of future land
use changes.
Ongoing
EPA is awaiting the completion of several Focused
Feasibility Studies and additional investigations to further
inform the development of new Decision Documents.
TRW
Site
The remedy selected for
the TRW Site is no
longer being operated.
Select a revised remedy
which incorporates long-
term stewardship
measures for the current
vapor intrusion mitigation
measures in place, as well
as addresses potential
vapor intrusion in the
event of future land use
changes.
Ongoing
EPA is awaiting the completion of several Focused
Feasibility Studies and additional investigations to further
inform the development of new Decision Documents.
Offsite
OU
Outdoor air TCE levels
have shown a generally
upward trend over time
since regular sampling
commenced in January
2015.
Investigate contributions to
outdoor air TCE levels from
fugitive emissions from the
groundwater treatment
system and emissions from
the vapor intrusion
mitigation systems.
Completed
An extensive outdoor air investigation was performed in
2021 during the winter months. Based on the
investigation results, it seems unlikely that emissions from
the groundwater treatment system and from the vapor
intrusion mitigation systems are the primary contributors
to outdoor air TCE concentrations.
9/01/2021
Offsite
OU
The remedy selected for
the Offsite OU will not
be able to achieve the
remedial
action objective of
restoration of
groundwater in a
reasonable timeframe,
as defined in the ROD.
Conduct remedy
performance optimization
efforts, after investigating
whether hydrogeology is
adequately characterized.
A revised remedy may be
needed to achieve the
RAOs.
Ongoing
Workplans were submitted for additional characterization
studies for the Signetics Site as well as the downgradient
Offsite OU. Upon completion these will be utilized in
updating the CSM and provide direction for remedy
optimization.
32 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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OU#
Issue
Recommendations
Cu rrent
Status
Current Implementation Status Description
Completion
Date
(if applicable)
Offsite
OU
Indoor air sampling
results indicate that the
vapor intrusion pathway
is complete in some
buildings in the Offsite
OU.
Select a revised remedy
which addresses vapor
intrusion.
Ongoing
EPA is awaiting the completion of several Focused
Feasibility Studies and additional studies to further inform
the development of new Decision Documents.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU 33
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3.3. Work Performed During this Five-Y 'view Period
3.3.1. AMD 901/902 Thompson Place Site
During the most recent ISB operational event in 2020, there were significant decreases in
groundwater circulation because of clogged screens/filter packs following the introduction of a
lecithin-based product (Provect EDR CH4+). Rehabilitation of the five affected wells was
attempted in 2021 and included swabbing, surging, and pumping, but was unsuccessful. In
2023, treatment efforts using a product called Scrud Remover were not able to be fully
implemented due to the level of buildup, but other options are continuing to be evaluated.
Fortunately, there are other existing wells that can be utilized for additional substrate
amendment.
In 2021, Arizona State University and Haley & Aldrich carried out laboratory tests to
evaluate the potential for Microbial Chain Elongation (MCE) processes with acetate and
ethanol to be used as effective substrates for sustaining ISB at the AMD 901/902
Thompson Place Site. In 2023, a field test was conducted to determine if MCE processes
can be stimulated in-situ with the indigenous microbial community or if bioaugmentation is
needed. Results from this pilot test showed that microbial communities were not
stimulated and bioaugmentation is necessary to promote the generation of target
products. A plan for expanding MCE at the Site will be submitted for approval in 2024.
3.3.2. TRW Microwave Site
In 2019, Northrop Grumman initiated a refinement of the Environmental Sequence Stratigraphy
(ESS) CSM for groundwater at the Former TRW Microwave Site. This included an update to
facies maps for groundwater Zones A and B, updating the orientation of HSU-3, and minor
refinements to other hydrostratigraphic unit maps. The A Zone is now defined as the elevation
interval from approximately 40 feet msl (the ground surface) to 15 feet msl and contains HSU-3,
which occurs from 15 feet to 20 feet msl. The B1 Zone is now considered to be 15 feet to 0 feet
msl. Refinements to the ESS CSM allow for further understanding of subsurface conditions.
During the most recent Five-Year Review period, 2019-2023, groundwater continued to flow
generally to the north with slight variability between the individual zones. Annual groundwater
monitoring results indicate that there are likely impacts from off-site sources, but there is a
reported reduction in chlorinated compounds throughout the site.
A vapor intrusion (VI) work plan was submitted to EPA in 2022 for confirmatory sampling of the
mitigation measures in place. The plan included active sampling of sub-slab soil gas, indoor and
34 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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outdoor air using canisters, and passive long-term sampling of indoor and outdoor air using
Radiellos©. The sampling effort took place in May of 2023 and January 2024. Currently, TRW is
working on a sampling plan to characterize the exterior soil gas onsite.
3.3.3. Signetics Site and Offsite Operable Unit
In 2020, Locus Technologies submitted a Work Plan for Enhanced Anaerobic Bioremediation
Phase II Treatability Study for the Signetics Site. In late 2020, three additional A Zone wells were
installed and sampled prior to enhanced anaerobic biodegradation (EAB) injections at 12
injection points in an approximately 13,400 square foot area that contained the highest
concentrations of TCE, cis-l,2-DCE and Freon 113 in groundwater at the site. Groundwater
monitoring results from samples collected approximately 320 days following injections show
reductions in TCE between 28 and 100% compared to baseline results. After 18 months, a slight
rebound in concentrations occurred in most wells, but after 24 months concentrations of TCE
went back down with reductions between 6 and 100% compared to baseline results. A Work
Plan for additional high-resolution characterization using Membrane Interface Hydraulic
Profiling (MIHP) was submitted to the EPA in 2023 to further characterize the Signetics Site
source zone area. The MIHP high-resolution characterization was conducted in 2023 and a
report was submitted for EPA review in 2024. Another workplan was submitted in 2023 to
further characterize the extent of the VOC plume at the Offsite OU and the investigation is
currently ongoing.
An Indoor Air/Vapor Intrusion (VI) Sampling and Analysis Removal Work Plan was submitted in
2020 for the Offsite OU. This work plan details the approach to evaluate properties that have
not been fully investigated, and properties where investigations or mitigations are already
completed. Additionally, an extensive outdoor air investigation was performed in 2021 (Locus,
2021f) during the winter months to evaluate emissions from the groundwater treatment
system and emissions from the vapor intrusion mitigation systems and their potential
contributions to outdoor air TCE impacts at the Signetics Site and Offsite OU. The study
conducted satisfactorily met the objectives of characterizing emissions from the treatment and
mitigation systems. Based on the study results, it seems unlikely that the treatment and
mitigation systems are the primary contributors to outdoor air concentrations. Nevertheless,
this study showed that outdoor air TCE concentrations onsite is above the background
concentrations from outside site boundaries, therefore volatilizations from Triple Site
subsurface sources could have influenced the outdoor air TCE concentrations onsite during the
investigation period, which were most noticeable in the Southeastern (generally downwind)
area of the site. TCE concentrations were generally still within or below health protective
screening levels for residential indoor air exposure (0.48 |-ig/m3 to 2 |-ig/m3) based on EPA's
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
35
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target risk management range (10~6 to 10"4) and target hazard quotient of 1. Further evaluation
of Triple Site sources (e.g., areas with higherTCE concentrations in the A aquifer zone) potential
volatilization to outdoor air is needed as discussed below in section 4.2.
4. Five-Year Review Process
Community Notificatic ilvemerit and Si arviews
4.1.1. Five-Year Review Press Release
A public notice was made available in the Bay Area News Group, a local newspaper, on
February 9, 2024, announcing the Five-Year Review. EPA also issued a press release on February
8, 2024 (https://www.epa.gov/newsreleases/epa-review-effectiveness-cleanups-14-privately-
owned-california-superfund-sites-2024). notifying that the Site was undergoing a Five-Year
Review. Copies of the public notice tear sheet and press release are presented in Appendix D.
EPA also placed a notification on the Site website www.epa.gov/superfund/triplesite stating
that the Site was undergoing a Five-Year Review. EPA received two responses as a result of
these community notification activities; one from Lenny Siegel, Executive Director of the Center
for Public Environmental Oversight, and another from Ashley Gjovik, a Community Member
inquiring about the Five-Year Review process and requesting to submit comments. EPA
provided Lenny Siegel and Ashley Gjovik with interview questionnaires, as described in the
section below and included in Appendix E.
Results of the review and the report will be made available electronically on the Site's website
(https://www.epa.gov/superfund/triplesite) and at the Site information repository located at:
EPA Superfund Records Center
75 Hawthorne Street, Room 3110
San Francisco, California, 94105
4.1.2. Site Interviews
During the Five-Year Review process, site questionnaires were distributed to various
stakeholders and community members to document any perceived problems or successes with
the remedy that has been implemented. Jennifer Garnett, City of Sunnyvale Communications
Officer, Brant Burns, Director of Facilities & Operations for Sunnyvale School District, Lenny
Siegel, Executive Director of the Center for Public Environmental Oversight and Community
Member Ashley Gjovik were interviewed. The results of these interviews are summarized
below.
36 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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Overall, the interviewees felt that there was adequate communication from EPA regarding the
current status of the site and its activities but expressed that additional communications and
updates would be beneficial to all. Suggestions were provided for means of notifying residents
and businesses of the potential for vapor intrusion and for including informational links for the
Site. EPA is working with its community involvement coordinator on updated outreach
materials and methods to better notify and inform the community regarding potential vapor
intrusion risks at the site.
In addition to the concerns expressed above, interviewees expressed concern about tenants in
commercial buildings with existing vapor intrusion mitigation systems that have failed to
maintain or damaged the systems. Lastly, interviewees urged that updated decision documents
be issued by EPA to address current site conditions as the existing ones are over 30 years old.
Data Review
The data review focused on data collected during the last 5 years (2019 through 2023) from
monitoring reports, quarterly reports, and other associated reports provided to EPA. The
following sections are organized by groundwater, and vapor intrusion (VI) for each operable
unit to evaluate site conditions during the review period.
4.2.1. Ground Water
4.2.1.1 AMD 901/902 Thompson Place Site
The remedy as selected in the 1991 ROD is no longer operational. Currently, there is an ISB
treatability study program that has reduced concentrations in the groundwater treatment
zones at the AMD Site. TCE concentrations have decreased since the program started.
Breakdown products from TCE, including cDCE, vinyl chloride, ethane and ethene, are evident.
Although concentrations of COCs are decreasing across the site compared to before the
initiation of the ISB program, TCE concentrations increased in wells 23-S and 23-D by 81% and
4%, respectively, compared to 2005. Concentrations of vinyl chloride, a daughter product of
TCE and cDCE, increased significantly between 86% to 1965% compared to 2005 at wells 16-S,
28-MW, DW-2, X2A, and DW-7 indicating that degradation of VOCs is active and ongoing (Table
5). Nevertheless, the degradation is not complete and not resulting in less toxic chemicals (i.e.,
ethane and ethene). Therefore, additional soil gas and sewer gas investigation and monitoring
is recommended by EPA for this area.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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Table , ndwater Concentrati* fa
Well ID
TCE
cDCE
Vinyl Chloride
Mole Fraction
Ethene &
Ethane1
Start of
ISB
(2005)
Most Recent
(2023)
Start of
ISB
(2005)
Most Recent
(2023)
Start of
ISB
(2005)
Most Recent
(2023)
2023
A Zone
16-S
6.1
<0.50 (-100%)
29
7 (-76%)
37
92 (+149%)
4.5%
23-S
37
67 (+81%)
84
71 (-15%)
31
0.88 (-97%)
5.2%
28-MW
10
<0.50 (-100%)
26
3 (-88%)
28
350 (+1150%)
7.7%
DW-2
3.0
<0.50 (-100%)
110
6.9 (-94%)
<0.7
13 (+86%)
55%
X2A
200
<0.50 (-100%)
230
49 (-79%)
62
650 (+948%)
3.2%
BlZone
16-D*
740
<0.50 (-100%)
970
2.1 (-100%)
45
7.7 (-83%)
98%
23-D
230
240 (+4%)
390
5 (-99%)
56
<0.50 (-100%)
3.5%
PMW-2-1
82
35 (-57%)
6,700
4,700 (-30%)
2,300
390 (-83%)
1.4%
DW-1
440
<0.50 (-100%)
3,700
0.78 (-100%)
32
1.5 (-95%)
100%
DW-7
300
7 (-98%)
100
44 (-56%)
4.6
95 (+1965%)
3.3%
X1B
360
<0.50 (-100%)
1,600
5 (-100%)
120
33 (-73%)
23%
X2B1
420
<0.50 (-100%)
420
5.6 (-99%)
41
30 (-27%)
22%
B2 Zone
PMW-2-3
290
280 (-3%)
440
45 (-90%)
24
<0.50 (-100%)
2.6%
Concentrations reported in micrograms per liter (ng/L)
1 Mole fraction of Ethene and Ethane is calculated by dividing the number of moles of Ethene and Ethane by the
total number of moles of TCE, cDCE, VC, Ethene, and Ethane.
*ln 2018, the Bl-Zone well 16-D was replaced with DW-7 in the monitoring program with EPA approval.
Contaminated groundwater from upgradient sources, based on data from monitoring wells 29-
S, 29-D, 53-D, S157A and S157B1, likely impacts groundwater concentrations at the AMD site.
The groundwater direction for the A, Bl, B2, and B3 zones remains to the north-northeast, and
pumping from the GWETS operation at the Signetics Site does not appear to affect groundwater
flow direction.
During this review period Mann-Kendall analyses on selected wells for the previous 10 years
(Appendix B) show increasing or decreasing trends for the A zone; stable or decreasing trends
for the Bl Zone; and mixed trends, either stable, increasing, or decreasing for the B2 and B3
zones.
Fluctuations in the A, Bl, and B2 zones range from 3-5 feet that is typical for seasonal variation
in these units. The hydraulic gradient of these zones based on the most current data (2022) are:
38 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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1.) upward to no vertical gradient from the B2 to the B1 Zone based on only two well pairs
within the AMD 901-902 site (well pairs 27-DD/27-D and 22-DD/23-D), and
2.) an upward vertical gradient from the B1 to the A Zone from six well pairs (27-D/27-S, 23-
D/22-S, 53-D/15-S, DW-7/16-S, 28-D, 28-S, and 29-D/29-S).
No analyzed COCs were detected in the only well screened in the B3 Zone (35-DDD) onsite.
Based on the data available, it appears there is vertical containment onsite.
4.2.1.2 TRW Microwave Site
The remedy as decided in the 1991 ROD is no longer in place. Concentrations of TCE in the A
and B1 zones had dropped significantly after the EAB treatability study program began in 2000.
The Site groundwater concentrations are impacted by upgradient contaminated groundwater
sources, as indicated by data from monitoring wells T-7A, T-5B, T-7B and T-20B presented in the
annual monitoring reports. During this review period, groundwater contaminant concentrations
throughout the TRW Site have remained consistent or decreased slightly. The Mann-Kendall
analyses on selected wells on aquifer zones A, B1 and B2 for the previous 10 years show that
most of those wells currently have no trend or are stable (Table 6).
Table 6. TKUW Groundwat icentrations Trends
Well
ID
GW
Zone
Analyte
n
Coefficient of
variation (COV)
MK
Statistic
(S)
Confidence
Factor (%)
Trend
Upgradient Wells
T-7A
A
TCE
13
0.35
-37
98.7
Decreasing
cDCE
12
0.53
-13
79
Stable
T-7B
B1
HSU1
TCE
13
0.43
-17
83.2
Stable
cDCE
13
0.48
-16
81.6
Stable
Source Area Wells
T-14A
A
TCE
14
0.8
54
99.9
Increasing
cDCE
14
0.26
12
72.3
No Trend
T-8B
B1
HSU3
TCE
13
0.78
2
52.4
No Trend
cDCE
13
0.46
15
79.9
No Trend
T-12C
B2
TCE
11
0.87
-7
67.6
Stable
cDCE
11
1.21
-2
53
No Trend
Downgradient Wells
T-9A
A
TCE
11
0.25
-32
99.4
Decreasing
T-16A
A
TCE
11
0.28
-6
64.8
Stable
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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Well
ID
GW
Zone
Analyte
n
Coefficient of
variation (COV)
MK
Statistic
(S)
Confidence
Factor (%)
Trend
cDCE
11
0.11
-17
89.1
Stable
T-10B
Bl
HSU1
TCE
12
0.6
-8
68.1
Stable
cDCE
12
0.5
3
55.4
No Trend
T-11C
B2
TCE
11
0.55
-11
77.7
Stable
cDCE
11
0.53
0
45.1
Stable
Cross gradient Well
T-17B
Bl
HSU2
TCE
15
0.41
-11
68.7
Stable
cDCE
15
0.46
15
79.9
No Trend
The groundwater flow directions for the A, Bl, and B2 zones at the TRW Site range from the
north to the north-northeast. However, the hydrostratigraphic units within the aquifer zone can
also modify the flow pathway on a local scale. In general, chemical contaminant concentrations
decrease as groundwater moves northward through the TRW Site.
The TRW Site has monitoring wells screened in hydrostratigraphic zones A through
B4. Fluctuations in these zones are less than 2 feet and the majority less than 1-foot of seasonal
fluctuation (measurements taken in October and December 2022). Vertical hydraulic gradients
taken from the 2022 measurements of wells in separate zones but clustered together onsite
have differing gradients. The well cluster in the northwest corner of the site has upward
gradients between B4 through Bl zones (wells T-8D, T-12C, and T-8B) but a slight upward or no
gradient from Bl to A zone (T-8B to T-8A). A well cluster in the southern portion of the site has
no vertical gradient between Zones B2 (36DD) and Bl (T-18B) but an upward gradient between
Bl and A (T-18B and 36D/36S). Based on the data available, it appears there is vertical
containment onsite.
4.2.1.3 Offsite OU
During this review period, available data for the Offsite OU indicated that groundwater will not
achieve ROD Remediation levels for several decades (Table 7 and Appendix B). Concentrations
of TCE still exceed MCL of 5 |j,g/L in one or more aquifer zones (Table 8). Mann-Kendall analysis
in selected wells indicates that TCE concentrations in the aquifer zones have mixed trends of
stable, decreasing, increasing and no trend (Table 8 and Appendix B). The available data for the
northern uppermost downgradient area in the A Zone indicate containment in the A Zone. The
data available for the Bl Zone in the northern uppermost downgradient area (COM63-B1)
40 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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indicate concentrations migrating offsite. Additional investigation to further characterize and
delineate the plume extent in the A and B1 aquifer is currently ongoing.
An extraction well (COM55A), located offsite on the western site boundary on Blythe Avenue,
presents an increasing TCE concentration trend. This well is located west of Sunnyvale East
Drainage Channel. Based on the currently available data and the fact this is an extraction well, it
is difficult to determine the plume dynamics at this location, and EPA recommends further
evaluation.
Table 7. Linear projections for OOU to Reach ROD Remediation Levels for TCE
Well
Projected Year Cleanup
S077A
2100
COM39A
2060
COM60B1
2070
S077B1
2050
COM06B2
2100
COM60B2
2065
Table 8. Offsite Operable Unit Groundwater Concentration Trends
Well ID
GW
Zone
n
Coefficient
of variation
(COV)
MK Statistic
(S)
Confidence
Factor (%)
2022 TCE
Concentration
(ug/l)
Trend
Southern Portion of Plume
upgradient of OOU and near the Signetics site boundary)
S075A2
A
11
0.57
4
59
73
No Trend
S075B
B1
11
1.56
25
97
560
Increasing
Duane Avenue
COM06A
A
11
0.22
-30
99
130
Decreasing
COM06B2
B2
11
0.21
-20
92.9
350
Prob. Decreasing
COM09B3
B3
11
0.23
21
94
390
Prob. Decreasing
Center of Plume South of San Miguel School
COM01A
A
11
0.56
-2
53
67
Stable
COM01B1
B1
11
0.16
8
70.3
120
No Trend
COM01B2
B2
11
0.07
3
56
190
No Trend
Center of Plume East of San Miguel School
COM04A
A
11
0.13
-13
82.1
22
Stable
Blythe Avenue - West of Sunnyvale East Drainage Channel -
COM55A
A
11
0.34
24
96.4
14
Increasing
Center of Plume North of San Miguel School
COM03A
A
11
0.14
-16
87.5
130
Stable
COM03B
B1
11
0.14
0
45.1
59
Stable
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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Well ID
GW
Zone
n
Coefficient
of variation
(COV)
MK Statistic
(S)
Confidence
Factor (%)
2022 TCE
Concentration
(ug/l)
Trend
COM03B2
B2
11
0.31
24
96.4
280
Increasing
COM06B3
B3
11
0.26
-21
94
210
Prob. Decreasing
COM06B4
B4
11
0.39
-37
99.8
49
Decreasing
Northern furthest downgradient onsite
COM49A
A
9
0.19
0
46
8*
Stable
COM46A
A
10
0.34
27
99.2
5*
Increasing
COM41A
A
10
0.12
6
66.8
38
No Trend
COM05A
A
10
0.42
8
72.9
5*
No Trend
COM50B1
B1
10
0.52
33
99.9
3.3*
Increasing
Northern furthest downgradient offsite
COM63B1
B1
11
0.31
2
53
35
No Trend
*TCE Data from 2023 was included.
For the Offsite Operable Unit, a vertical gradient evaluation was conducted by the responsible
party contractor (Locus) at well pairs and clusters in their 2022 annual groundwater monitoring
report (Locus, 2022). The evaluation noted both upward, downward and no gradients in the
OOU between the A and B1 Zones, primarily downward gradients between the B1 and B2
Zones, upward gradients between the B2 and B3 zones, and primarily upward in the B3 and B4
zones. However, some well pairs between B3 and B4 have no gradient and one downward
gradient was noted in the well pair COM06B3/B4, these wells are operating extraction wells,
and the direction of the vertical gradient can fluctuate with the time of level measurement.
Based on the data available, it appears there is vertical containment in the OOU.
4.2.2. Vapor Intrusion
During the previous 2019 Five-Year Review period, VI risks for the existing primary building at
the AMD 901/902 site, the self-storage building at 875 East Arques was found to be very low
and, as such, no VI specific work was done on that Site during the 2024 Five-Year Review
period. An extensive outdoor air study performed at Triple Site (Locus, 2021f), as described
below, showed an outdoor air TCE concentration of 2.3 |-ig/m3 near the source area at AMD Site
under winter conditions. Further evaluation of AMD Site source volatilization to outdoor air and
its potential to influence TCE outdoor air concentrations onsite is needed. For this evaluation
EPA recommends investigating soil gas and sewer gas near the source and evaluating their
potential emissions to outdoor air. Additionally, an adjacent property to the north of the AMD
Site boundary is in close proximity to the source zone area on the AMD Site, therefore, the
42 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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recommended soil gas and sewer gas investigation may also apply to identify potential impacts
to the property on the north side boundary.
VI risks at TRW building were mitigated in 2015. In 2023 and 2024 vapor intrusion confirmatory
sampling were performed and confirmed that the mitigation measures were still effective in
preventing vapor intrusion above acceptable risk levels. There is no evidence of unacceptable
vapor intrusion risk for the current commercial building on-site. However, monitoring for
long-term stewardship is required to ensure the mitigation measures remain effective in the
long-term. Additionally, exterior soil gas investigation is needed to update the Conceptual Site
Model and update the focused feasibility study for EPA to select a revised groundwater remedy
for the TRW Site.
Efforts to monitor and mitigate vapor intrusion are ongoing at the Offsite OU as discussed
below.
4.2.2.1 Offsite OU
Residential indoor air sampling in the Offsite OU under EPA oversight began in January 2015
and is ongoing. To date approximately 237 residential addresses (units) have been sampled and
approximately 35 school buildings have been sampled to assess vapor intrusion.
In the 2024 Five-Year Review period, between 2019 and 2023, the vapor intrusion investigation
activities performed collected over 1,000 air samples that included over 400 samples (indoor air
and crawlspace air) from residential properties and almost 500 samples (indoor air and
crawlspace air) from school buildings. Operation and maintenance are ongoing on about 25
mitigation systems that were installed; 12 at school buildings and 13 at residential units. EPA is
working on obtaining access on 58 additional residential addresses where access for sampling
has not been obtained despite multiple attempts. EPA is increasing community involvement
efforts to encourage residents to provide access. The table below summarizes the samples
collected during the vapor intrusion investigation activities.
Vapor Intrusion Investigation
Since 2015
2019-2023
Overall number of air samples collected
4,905
1,059
Air samples collected in residential buildings
(indoor + crawlspace)
2,664
421
Air samples collected in school buildings
(indoor + crawlspace)
1,646
475
Outdoor air samples collected
595
163
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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Vapor Intrusion Investigation
Since 2015
2019-2023
Residential addresses (units) sampled
237
58
School buildings sampled
35
35
School classrooms sampled
126
104
Mitigation systems installed in residential
units
13
1
Mitigation systems installed in school
buildings
12
0
Mitigation systems under ongoing
operation and maintenance
-- 25 --
Buildings with access issues
- 58 -
An extensive outdoor air study (Locus, 2021f) was conducted in February 2021 during winter
meteorological inversions, to mimic maximum exposure conditions. Two identical rounds of
outdoor air sampling events were conducted. In each round, fifty-two (52) onsite outdoor air
locations were sampled within and throughout the Signetics and Offsite OUs, additionally,
twelve (12) background outdoor air locations (outside site boundaries) were sampled. Results
from the 52 onsite locations ranged from 0.44 |-ig/m3 in the northwest area of Triple Site to
2.3 |-ig/m3 in the southeast area where the Signetics and AMD groundwater source areas are
located. Results from the 12 background locations were below detection limit (0.14 |-ig/m3) in
most of the investigated locations, but where it was detected TCE concentrations ranged from
0.28 |-ig/m3 on the northwest up to 1.2 |-ig/m3 east of Triple Site. The onsite data shows a clear
spatial pattern with concentrations above 1 |-ig/m3 common in the Southeastern (downwind)
portion of the Triple Site, especially in the area South of East Duane Avenue. Based on the
background data collected there is no indication of regional scale sources contributing to
outdoor air concentrations at Triple Site. Based on the prevailing wind direction during the
outdoor air sampling, local sources and off-gassing from the groundwater plume could
potentially be contributing to outdoor air concentrations during the study period. Further
investigation is needed to evaluate if volatilization to outdoor air from Triple Site subsurface
sources (e.g., areas of higher TCE concentrations in the A aquifer zone) could potentially
influence the TCE outdoor air concentrations onsite. For this evaluation EPA recommends
investigating sewer gas and soil gas concentrations at appropriate locations
44 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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4.2.3. Climate Resilience Screening
California's Fire Hazard Severity Zone Maps indicate that the Site is outside of the state
responsibility area for fire hazards. The Department of Agriculture Forest Service indicates the
Site is a Low Risk for wildfires. The Sites are located in an area listed as a moderate flood hazard
by the Government Accountability Office's Superfund Climate Change interactive map. This
flood hazard has the potential to temporarily reduce the effectiveness of the vapor mitigation
systems that is currently in place at the site, but it could also temporarily reduce the flow rate
of soil gas into buildings which decreases the potential for occurrence of vapor intrusion.
Furthermore, if any of the groundwater monitoring wells are not properly sealed and in good
condition, surface water and potentially seawater has the potential to inundate the wells. In
addition to the potential flood risks, rolling blackouts due to increased power usage in the
summer months may impact the effectiveness of the groundwater extraction and treatment
systems over short periods.
The Triple Site locations are situated in the South Bay Area region adjacent to the San
Francisco Bay. The Bay Area is known for seismic activity and thus could make the existing
remedies prone to earthquake damage during future events. Seismic impacts could result
in electrical power interruptions which could result in the loss of containment for
groundwater treatment or soil vapor mitigation systems. Additionally, earthquake impacts
could result in structural damage to the treatment systems protective enclosures and
various components of the existing systems.
4,3. Site Inspection
The inspection of the Site was conducted on March 5, 2024. In attendance were Dr. Lilian
Abreu, Lead agency, Matthew Wetter and Cody Davis of the U.S. Army Corps of Engineers,
Joshua Nandi of Northrop Grumman, Akash Caveney and Michael Zlotoff of Haley & Aldrich,
and J. Wesley Hawthorne and Africa Espina of Locus Tech. The purpose of the inspection was to
assess the condition of the remedy and verify that the remedy is operating as intended.
The inspection included visual observation of overall site conditions and inspection of various
components of the remedy including groundwater treatment system (plant and well network),
and several extraction, injection, and monitoring wells. The participants received an overview
of the sites and a brief remedial history generally provided by Northrop Grumman, Haley
Aldrich, and Locus Tech staff. The weather was overcast, with a slight breeze, and
approximately 60 degrees Fahrenheit. Site Inspection documentation, photos and summary are
included in Appendix F.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
45
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5. Technical Assessment
stion A; Is the remedy functioning as intended by the decision
documents?
At the AMD and TRW sites, the remedy is not working as intended. Components of the selected
remedy are either no longer in place or operational. The groundwater extraction and treatment
system at the AMD Site is not in use nor operational and at the TRW Site the system is no
longer in place. Nevertheless, the groundwater extraction and treatment remedies (while still in
operation) and the addition of in-situ bioremediation treatability studies at the AMD and TRW
Sites have resulted in substantial decreases in concentrations of chemical contaminants since
the remedy began operations. Continued in-situ bioremediation efforts, combined with the
institutional controls currently being implemented at the AMD and TRW Sites, and the
mitigation measures in place at the TRW Site, are providing protectiveness.
The selected remedy for the Offsite OU is currently in operation but is not fully functioning as
intended. Generally, it is controlling contaminant migration in groundwater but the projection
for aquifer restoration will be in the 2050-2100 timeframe; this is well beyond the ROD-
estimated projected restoration time of 2027.
stk ire the exposure assumptions, Toxicity Data, Cleanup Levels,
dial Actio actives Used at the Tir. nedy Selection Still
Valid?
No, the exposure assumptions used at the time are not still valid. The vapor intrusion pathway
is complete and at the time the ROD was signed this was a relatively new exposure scenario and
assumptions related to this pathway were not well established.
There have been no changes to ARARs (Appendix C) issued in the ROD that would affect the
protectiveness of the groundwater remedy for the AMD and TRW Sites and Offsite OU.
Groundwater cleanup standards have not changed since the ROD was issued. No new
contaminants have been identified since the ROD.
Land use has not changed at the AMD and TRW Sites and Offsite OU since the last Five-Year
Review. An environmental covenant and a covenant and agreement for the AMD and TRW
Sites, respectively, are in place that prohibits installation of groundwater wells for domestic use
at the AMD and TRW sites.
46 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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stic Any Other Information Come to Light That Cot
Questic ytectiveness of the Remedy ?
Yes, there is new information that calls into question the protectiveness of the remedy: the
water discharge from a sump-pump in the basement of the building located at 440 North Wolfe
Rd. (Signetics Site) was diverted from the treatment system and currently is being discharged
untreated into the sanitary sewer system. Up until 2020, the responsible party was treating the
water prior to discharging it to the Sunnyvale East Drainage Channel under a NPDES permit. In
December 2020, the responsible party removed the 440S sump-pump discharge from the
treatment system influent and diverted it to the sanitary sewer system (Locus, 2021d).
Compliance with the City of Sunnyvale limits for discharge of untreated water into the sanitary
sewer is required as well as monitoring on an ongoing basis.
6. Issues/Recommendations
TabI syes a commendations Identified in the Five-Year Review
Issues and Recommendations Identified in the Five-Year Review:
OU(s): AMD Site
Issue Category: Remedy Performance
Issue: The remedy selected for the AMD Site is no longer being operated.
Recommendation: Update the conceptual site model with appropriate
soil gas and sewer gas data to evaluate the potential for contaminant
migration downgradient and into the adjacent property north of the Site
boundary.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2026
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
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OU(s): AMD Site
Issue Category: Remedy Performance
Issue: Outdoor air TCE concentration of 2.3 |J,g/m3 (within EPA risk
management range for indoor air exposure) was observed next to the
source zone area at the AMD Site under winter conditions.
Recommendation: Investigate if potential volatilization to outdoor air
from the AMD subsurface source is influencing the outdoor air TCE
concentrations onsite.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2027
OU(s): TRW Site
Issue Category: Remedy Performance
Issue: The remedy selected for the TRW Site is no longer being operated.
Recommendation: Implement exterior soil gas investigation and
monitoring at the site. This information will be used to update the
Conceptual Site Model.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2026
48 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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OU(s): Offsite
OU
Issue Category: Remedy Performance
Issue: Outdoor air TCE concentrations up to 2.3 |J,g/m3 (within the EPA risk
management range for indoor air exposure) was observed in the
southeastern portion of the Triple Site under winter conditions.
Recommendation: Investigate if potential volatilization to outdoor air
from Triple Site subsurface sources (e.g., areas with higher TCE
concentrations in the A aquifer zone) is influencing the outdoor air TCE
concentrations onsite.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2027
OU(s): Offsite
OU
Issue Category: Remedy Performance
Issue: The remedy selected for the Offsite OU will not be able to achieve
the remedial action objective of restoration of groundwater in a
reasonable timeframe, as defined in the ROD.
Recommendation: Perform focused feasibility studies for EPA to select
alternative remedies.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2027
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
49
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OU(s): Offsite
OU
Issue Category: Remedy Performance
Issue: Indoor air sampling results indicate that the vapor intrusion
pathway is complete in buildings in the Offsite OU and an updated
conceptual site model for a focused feasibility study is needed.
Recommendation: Update the conceptual site model by collecting
appropriate exterior soil gas and sewer gas samples at this operable unit.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2026
OU(s): Offsite
OU
Issue Category: Other
Issue: Some buildings in the designated vapor intrusion study area have
access issues.
Recommendation: Increase community involvement efforts to encourage
property owners to provide access.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
EPA
EPA
8/31/2025
OU(s): Offsite
OU
Issue Category: Monitoring
Issue: Discharge of untreated contaminated groundwater into the
sanitary sewer system at 440 North Wolfe Rd.
Recommendation: Compliance with the City of Sunnyvale limits for
discharge of untreated groundwater into the sanitary sewer is required
and monitor it for compliance on an ongoing basis.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight Party
Milestone Date
No
Yes
PRP
EPA
9/30/2025
50 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Othi lings
Although the Signetics Site as discussed above is not on the NPL, it was included in the original
Triple Site ROD and is an integral part of current management of the Triple Site. It is
recommended that the Signetics Site formally be included in the next and subsequent five-year
reviews.
An extraction well (COM55A), located offsite on the western site boundary on Blythe Avenue,
presents an increasing TCE concentration trend. This well is located west of Sunnyvale East
Drainage Channel. Based on the currently available data and the fact this is an extraction well, it
is difficult to determine the plume dynamics at this location, and EPA recommends further
evaluation.
The southern border of Triple Site receives contaminated groundwater from upgradient
sources, based on data from monitoring wells 29-S, 29-D, 53-D, S157A and S157B1. TCE
groundwater concentration of up to 71 |j,g/L (well S157B1) is migrating into the site. The
Regional Water Board's GEOTRACKER database shows that several sites (Figure 4) managed by
the Regional Water Board could potentially be upgradient sources. Some of these sites have
been closed by the Water Board, and others have open status. EPA is seeking collaboration with
the Regional Water Board to address these potential upgradient sources.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
51
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csou - Convrencai Sttet Operate unK
soou - Stewart Dfve operable jr.:
Source: Adapted from Haley & Aldrich slide presentation to EPA R9 2022.
Figure 4. Some Upgradient TCE Sites from the GEOTRACKER Database
52 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
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7. Protectiveness Statement
Table 10. Protectiveness Statement
Protectiveness Statement(s)
Operable Unit: AMD Site Protectiveness Determination:
Short-term Protective
Protectiveness Statement: The remedy at the AMD Site currently protects human health and
the environment because exposure pathways for soil and groundwater are controlled and
there is no evidence of unacceptable vapor intrusion risk for the current commercial land
use. However, in order for the remedy to be protective in the long-term, soil gas and sewer
gas investigations are needed to further evaluate site conditions, update the conceptual site
model, and update the focused feasibility study. Additionally, based on Triple Site outdoor
air study findings, further investigation is needed to evaluate if potential volatilization to
outdoor air from the AMD subsurface source is influencing the outdoor air TCE
concentrations onsite. Finally, EPA should select a revised groundwater remedy for the AMD
Site, as the groundwater extraction and treatment system, a key element of the remedy
selected in the 1991 Record of Decision, is no longer operating. The revised remedy should
also address vapor intrusion in the event of future land use changes, as vapor intrusion
evaluation was limited in the 1991 ROD. Also, a new environmental covenant should be
recorded.
Protectiveness Statement(s)
Operable Unit: TRW Site Protectiveness Determination:
Short-term Protective
Protectiveness Statement: The remedy for the TRW Site currently protects human health and
the environment because exposure pathways for soil and groundwater that could result in
unacceptable risks are prevented through a land use covenant and agreement. There is no
evidence of unacceptable vapor intrusion risk for the current commercial building on-site.
However, in order for the remedy to be protective in the long-term, EPA should select a
revised groundwater remedy for the TRW Site, as the groundwater extraction and treatment
system, a key element of the remedy selected in the 1991 Record of Decision, is no longer
onsite. The revised remedy should also address vapor intrusion in the event of future land
use changes, as vapor intrusion evaluation was limited in the 1991 ROD.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
53
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Protectiveness Statement(s)
Operable Unit:
Off site OU
Protectiveness Determination:
Short-term Protective
Protectiveness Statement: The remedy for the Offsite Operable Unit currently protects
human health and the environment because there are no direct exposures to groundwater,
and the vapor intrusion pathway is being controlled through investigation of indoor air and
installation of mitigation measures where necessary and where access has been granted.
However, in order for the remedy to be protective in the long-term, a revised remedy is
needed to achieve the RAOs in reasonable time and to ensure the long-term stewardship of
the vapor intrusion mitigation measures currently in place. For EPA to select a revised
remedy, a focused feasibility study that incorporates an updated conceptual site model with
information from appropriate exterior soil gas and sewer gas investigation is needed. Finally,
based on Triple Site outdoor air study findings, further investigation is needed to evaluate if
potential volatilization to outdoor air from Triple Site subsurface sources (e.g., areas with
higherTCE concentrations in the A aquifer zone) is influencing the outdoor airTCE
concentrations onsite.
The next Five-Year Review report forTriple Site (AMD 901/902, TRW and Signetics Sites and the
Offsite OU) is required five years from the completion date of this review.
8. Next Review
54 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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Appendix A:
List of Documents Reviewed
General/Other
EPA, 1991. Record of Decision, Advanced Micro Devices #901/902, Signetics, TRW Microwave.
Combined Superfund Sites, Sunnyvale, California, September 11, 1991.
EPA, 2019. Fifth Five-Year Review Report for Advanced Micro Devices 901/902 & TRW
Microwave Superfund Sites. September 18, 2019.
AMD 901/902
Haley & Aldrich, 2022a. Semiannual In Situ Bioremediation Program Progress Update - October
2021 through March 2022, Former 901/902 Thompson Place. April 29, 2022.
Haley & Aldrich, 2022b. Semiannual In Situ Bioremediation Program Progress Update - April
through September 2022, Former 901/902 Thompson Place. October 18, 2022.
Haley & Aldrich, 2023. 2022 Annual Groundwater Monitoring Report, Former 901/902
Thompson Place. January 23, 2023.
Haley & Aldrich, 2023a. Semiannual In Situ Bioremediation Program Progress Update - October
2022 through March 2023, Former 901/902 Thompson Place. April 24, 2023.
Haley & Aldrich, 2023b. Semiannual In Situ Bioremediation Program Progress Update - April
through September 2023, Former 901/902 Thompson Place. October 24, 2022.
Haley & Aldrich, 2024. Combined 2023 Annual Groundwater Monitoring Report and Sixth Five-
Year Review Report, Former 901/902 Thompson Place. February 29, 2024.
TRW
Burns & McDonnell, 2020. Development of the Environmental Sequence Stratigraphy (ESS)
Conceptual Site Model (CSM) for Groundwater at the Former TRW Microwave Site, 825
Stewart Drive. December 5, 2020.
Northrop Grumman, 2021. 2020 Annual Groundwater Monitoring Report, Former TRW
Microwave Site, 825 Stewart Drive, February 26, 2021.
Northrop Grumman, 2022. 2021 Annual Groundwater Monitoring Report, Former TRW
Microwave Site, 825 Stewart Drive, March 17, 2022.
Northrop Grumman, 2023. 2022 Annual Groundwater Monitoring Report, Former TRW
Microwave Site, 825 Stewart Drive, June 1, 2023.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
55
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Northrop Grumman, 2023. Revised Vapor Intrusion Work Plan Addendum #3, Former TRW
Microwave Site, 825 Stewart Drive, February 2, 2023.
Northrop Grumman, 2024. 2023 Annual Groundwater Monitoring Report, Former TRW
Microwave Site, 825 Stewart Drive, March 14, 2021.
Offsite OU & Signetics (Philips)
Locus Technologies, 2019. Work Plan, Enhanced Anaerobic Bioremediation Phase II Treatability
Study, Signetics Site. October 16, 2019.
Locus Technologies, 2020a. Annual Groundwater Monitoring Report January to December
2019, Signetics (811 East Arques Avenue) Site and Offsite Operable Unit. April 30, 2020.
Locus Technologies, 2020b. Work Plan, Enhanced Anaerobic Bioremediation Phase II
Treatability Study, Signetics Site. June 23, 2020.
Locus Technologies, 2020c. QAPP For Enhanced Anaerobic Bioremediation Treatability Study -
Phase II. June 23, 2020.
Locus Technologies, 2020d. Work Plan, Indoor Air/Vapor Intrusion Sampling and Analysis
Removal, Triple Site Offsite Operable Unit. November 9, 2020.
Locus Technologies, 2021a. Injection Completion Report, Enhanced Anaerobic Bioremediation
Phase II Treatability Study, Signetics Site. January 4, 2021.
Locus Technologies, 2021b. Quarterly VI Records Report - 23 November through 31 December
2020, Triple Site Offsite Operable Unit (OOU) Superfund Site. February 1, 2021.
Locus Technologies, 2021c. Quarterly VI Records Report - 1 January through 31 March 2021,
Triple Site Offsite Operable Unit (OOU) Superfund Site. April 30, 2021.
Locus Technologies, 2021d. Five-Year Status Report and Remedial Effectiveness Evaluation 2016
to 2020, Signetics (811 East Arques Avenue Site and Offsite Operable Unit. July 20, 2021.
Locus Technologies, 2021e. Quarterly VI Records Report - 1 April through 30 June 2021, Triple
Site Offsite Operable Unit (OOU) Superfund Site. July 30, 2021.
Locus Technologies, 2021f. Technical Memorandum, Outdoor Air Evaluation, The Triple Site
Signetics Site and Offsite Operable Unit Superfund Site). September 1, 2021.
Locus Technologies, 2021g. Monthly VI Progress Report for October 2021, Triple Site Offsite
Operable Unit (OOU) Superfund Site). November 10, 2021.
Locus Technologies, 2022. Annual Groundwater Monitoring Report January to December 2021,
Signetics (811 East Arques Avenue) Site and Offsite Operable Unit. April 29, 2022.
56 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Locus Technologies, 2023a. Treatability Study Work Plan for Additional Characterization,
Signetics Site. March 24, 2023.
Locus Technologies, 2023b. Annual Groundwater Monitoring Report January to December
2022, Signetics (811 East Arques Avenue) Site and Offsite Operable Unit. April 28, 2023.
Locus Technologies, 2023c. Treatability Study Work Plan for Additional Characterization,
Signetics and OOU Sites. June 14, 2023.
Locus Technologies, 2023d. Sampling and Analysis Plan, Signetics and OOU Sites. August 4,
2023.
Locus Technologies, 2023d. Work Plan, Groundwater Plume Characterization, Triple Site Offsite
Operable Unit. August 21, 2023.
Locus Technologies, 2023e. Additional Characterization Evaluation Report, EAB Treatability
Study Area, Signetsics Site. December 15, 2023.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
57
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Appendix B: Data Review
Groundwater
AMD 901/902 Thompson Place Site
The groundwater monitoring program at the AMD Site OU (also known as AMD 901/902)
consists of two parts: 1) the annual site-wide groundwater monitoring sampling program and 2)
quarterly groundwater samples to assess the effectiveness of the ISB and selected
modifications. The data review utilized the annual groundwater data from 2019 to 2023 for the
AMD Site (Haley Aid rich, 2020, 2021, 2022, 2023, 2024). Annual groundwater data indicate that
four COCs (TCE, cDCE, tDCE, and vinyl chloride) remain at levels above cleanup standards at the
site in the A, Bl, and B2 zones. The number of wells with COCs exceeding the MCLs is shown in
Table B-l.
A Zone
The ISB program has reduced concentrations within the A Zone. In the existing wells 16-S, 22-S,
23-S and 28-S, concentration have declined since ISB startup. The one exception is well 27-S,
which has concentrations an order of magnitude greater than nearby wells. Breakdown
products of TCE, including cDCE and vinyl chloride, are evident on the concentration trend plots
(Figure B-l). Increases in vinyl chloride concentrations suggest anaerobic bioremediation is
occurring, most significantly in the A zone.
The direction of groundwater flow in the A Zone is to the north-northeast (Figure B-2), Freon
113 was not used at the AMD Site, but it is found co-mingled with elevated levels of cDCE along
the western boundary of the site (Figure B-2).
Mann-Kendall analysis indicates that in the last 10 years (duration used for significant statistical
analysis), TCE concentrations in source area A Zone wells, 22-S and 23-S, have either a
decreasing or increasing trend, respectively. These trends are likely due to the influence of TCE
being desorbed from the soil into the groundwater (Figure B-3). TCE concentrations in
downgradient wells 36-S and 37-S both show decreasing trends, but concentrations are still
above MCL's, which is also likely due to the influence of TCE desorption from soil into
groundwater (Figure B-4).
Bl Zone
In the Bl zone, concentrations of TCE and breakdown products, including cDCE and vinyl
chloride, have declined since ISB startup (Figure B-5). The direction of groundwater flow in the
58 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
B1 zone is to the north-northeast (Figure B-6). Mann-Kendall analysis indicates that in the last
10 years, TCE concentrations in B1 zone wells 23-D and 52-D have either stable or decreasing
trends, respectively. The lingering stable trend is likely due to TCE sorbed onto subsurface soils
and back-diffusing into groundwater (Figure B-7). TCE concentrations along the western
property boundary and within the source area are elevated above the MCL. Wells 23-D and 27-
D, located along the western property boundary contain elevated concentrations of TCE and
are not responding to the ISB as other onsite wells (Figure B-6).
B2 and B3 Zone
ISB activities are reducing off-site, down-gradient concentrations from the source area in the B2
Zone. Based on the presence of breakdown products, it appears that bioremediation is actively
occurring (Figure B-8). The direction of groundwater flow in the B2 zone is to the north-
northeast (Figure B-9). Mann-Kendall analysis indicates that in the last 10 years, TCE
concentrations in various B2 and B3 zone wells showed mixed trends, either stable, increasing,
or decreasing (Figure B-10). Like the A and B1 zones, the variability and lack of a clear trend is
likely due to TCE is sorbed onto subsurface soils and back-diffusing into groundwater. Though
TCE concentrations remain above the MCL, levels are gradually declining at well 27-DD despite
being up-gradient of the treatment area (Figure B-ll).
Table iary Data Collected During the Recent Five riiod
AMD Data
2019
2020
2021
2022
2023
Maximum Water Elevation (A Zone), feet msl
42.26
42.18
41.71
40.76
41.50
Minimum Water Elevation (A Zone), feet msl
35.37
35.28
35.12
34.76
34.93
Maximum Water Elevation (B1 Zone), feet msl
43.95
43.68
43.11
42.22
43.15
Minimum Water Elevation (B1 Zone), feet msl
35.40
35.31
35.18
34.81
35.05
Maximum Water Elevation (B2 Zone), feet msl
43.53
42.83
41.88
41.15
42.61
Minimum Water Elevation (B2 Zone), feet msl
36.80
36.75
36.14
35.65
36.18
Water Elevation at 35-DDD (B3 Zone), feet msl
42.87
41.59
40.45
40.09
41.80
Number of A-Zone Wells with VOCs> MCL
8
8
9
8
8
Number of Bl-Zone Wells with VOCs> MCL
7
7
7
7
8
Number of B2-Zone Wells with VOCs> MCL
3
3
3
3
3
Maximum TCE Concentration (A Zone), ng/L
43
50
63
70
67
Maximum TCE Concentration (B1 Zone), ng/L
290
280
210
180
240
Maximum TCE Concentration (B2 Zone), ng/L
150
130
100
100
140
Maximum cDCE Concentration (A Zone), ng/L
290
250
250
140
200
Maximum cDCE Concentration (B1 Zone), ng/L
160
120
78
61
130
Maximum cDCE Concentration (B2 Zone), ng/L
12
16
16
15
14
Maximum VC Concentration (A Zone), ng/L
27
70
480
480
310
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
59
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AMD Data
2019
2020
2021
2022
2023
Maximum VC Concentration (B1 Zone), ng/L
450
1600
2800
1600
370
Maximum VC Concentration (B2 Zone), ng/L
72
18
7.4
8.0
16
Notes:
1. This table presents only data for wells in the annual monitoring program. In 2018, Bl-Zone
well 16-D was replaced with DW-7 in the monitoring program with EPA approval.
Abbreviations:
Hg/L = micrograms per liter MCL = Maximum Contaminant Level
cDCE = cis-l,2-dichloroethene TCE = trichloroethene
feet msl = feet above mean sea level VC = vinyl chloride
ISB = in situ bioremediation VOCs = volatile organic compounds
60 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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15-S
f'W ¦
' -Xld
*,«>«.««
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m»mnn r»c-c»«ri
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i i 1 '',/
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r t
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Figure B-l. Concentration Trends for Groundwater in select AMD A Zone wells
(Source: Haley & Aldrich, 2024).
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ
61
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Figure B-2. Groundwater flow and VOC concentrations in the AMD A Zone in
2023 (Source: Haley & Aldrich, 2024).
62 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
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GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date:
27-Mar-24
Job ID:
Source Area A Zone
Facility Name:
AMD 901/902
Constituent:
TCE
Conducted By:
A. Provow
Concentration Units:
ug/L
Sampling Point ID:
22S
23S
I I
Sampling
Event
Sampling
Date
TCE CONCENTRATION (ug/L)
1
1-Oct-13
28
37
2
1-Oct-14
36
36
3
1-Oct-15
45
20
4
1-Oct-16
47
6.9
5
1-Oct-17
34
23
6
1-Oct-18
43
38
7
1-Oct-19
4.9
43
8
1 -Oct-20
3.6
50
9
1-Oct-21
13
63
10
1 -Oct-22
14
70
11
1 -Oct-23
4.7
67
12
13
14
15
16
17
18
19
20
Coefficient of Variation:
Mann-Kendall Statistic (S):
-23 | 37 | |
Confidence Factor:
¦ 95.7% I 99.8% | I
I I
Concentration Trend:
Decreasing | Increasing
Sampling Date
Notes:
1. At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2. Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
> 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S<0, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41 (3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Too kit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, con-ectness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI Environmental Inc., www.gsi-net.com
Figure B-3. Mann-Kendall Statistics for TCE in A Zone Wells in the AMD Source
Area.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Off site OU
63
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ug/L
Sampling Point ID:
36S (A)
37S (A)
36D (B1)
36DD (B2)
i i i
Sampling
Event
Sampling
Date
TCE CONCENTRATION (ug/L)
1
1-Oct-13
74
95
38
0.1
2
1-Oct-14
73
83
56
0.1
3
1-Oct-15
71
49
40
0.1
4
1-Oct-16
71
43
2.7
0.1
5
1-Oct-17
59
420
4.2
4.3
6
1-Oct-18
59
33
6.1
0.84
7
1-Oct-19
58
37
43
1
8
1 -Oct-20
49
35
28
0.86
9
1-Oct-21
56
40
5.4
2
10
1 -Oct-22
48
27
11
1
11
1-Oct-23
49
31
9.4
0.83
12
13
14
15
16
17
18
19
20
Coefficient of Variation:
0.17
1.41
0.87
1.21
i
Mann-Kendall Statistic (S):
-48
-35
-9
22
i
Confidence Factor:
>99.9%
99.7%
72.9%
94.9%
i
Concentration Trend:
Decreasing
Decreasing
Stable
Prob. Increasing
1000
U)
3
£
O
c
0) or decreasing (S<0): >95% = Increasing or Decreasing;
£ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, SsO, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, con-ectness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to up date the information contained herein.
GSI Environmental Inc., www.gsi-net.com
Figure B-4. Mann-Kendall Statistics for TCE in downgradient wells in the AMD
Source Area.
64 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
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23 D
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Figure B-5. Concentration Trends for Groundwater in select AMD B1 Zone wells
(Source: Haley & Aldrich, 2024).
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ
65
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Figure B-6. Groundwater flow and VOC concentrations in the AMD B1 Zone in
2023 (Source: Haley & Aldrich, 2024).
66 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date:
27-Mar-24
Job ID:
Source Area B1 Zone
Facility Name:
AMD 901/902
Constituent:
TCE
Conducted By:
A. Provow
Concentration Units:
ug/L |
Sampling Point ID:| 23D
52D
i
I I
Event
Sampling
Date
TCE CONCENTRATION (uglL)
1
1-Oct-13
280
32
2
1-Oct-14
280
33
3
1-Oct-15
260
34
4
1-Oct-16
270
34
5
1-Oct-17
200
28
6
1-Oct-18
290
27
7
1-Oct-19
290
22
8
1 -Oct-20
280
16
9
1-Oct-21
210
16
10
1-Oct-22
180
14
11
1 -Oct-23
240
17
12
13
| 14
15
16
17
18
19
20
Coefficient of Variation:
I I
Mann-Kendall Statistic (S):
-15 | -37
I I
Confidence Factor:
85.9% ! 99.8%
1 1
Concentration Trend:
Stable | Decreasing
U)
3
C
O
c
0) or decreasing (S<0): >95% = Increasing or Decreasing;
£ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, SsO, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Too kit is available "as is". Considerable care has been exercised in preparing this software product; however no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI Environments line., www.gsi-net.com
Figure B-7. Mann-Kendall Statistics for TCE in B1 Zone Wells in the AMD Source
Area.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ
67
-------
1
Figure B-8. Concentration Trends for Groundwater in select AMD B2 and B3
Zone wells (Source: Haley & Aldrich, 2024).
68 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
HAI£Y - • 1 m - - '¦>
S2-2Ets = VOfl CQN2ENTRAT ONE
AND 3RGUNDVV.TEF? EL EVA" CSV S
OCTOCJER 282?
-t-.L. . . - "KilJR- -4
I PYT FH
3§> ix^jirrx:
Figure B-9. Groundwater flow and VOC concentrations in the AMD B2 Zone in
2023 (Source: Haley & Aldrich, 2024).
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ
69
-------
GS! MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Stable
1-Oct-12
IOCt-14
1-Ocl-15
1-Qct-16
1-Oct-17
1-Orrt-lfr
\O0\-21
-Mi I 41
33.8% I 101,0%
Decreasing Decreasing
—*^22DD . -95%Increask-ig ur Decreasing.
i 93^ - Probably icreashg nr Probably Decreasing; -"-90%and £>0 = No Trend: < B0%. SiD, aidCOV '* 1 = Mo Trend: '• 90% and COV < 1 = Sterile-.
3. Mahato ngy fcasrd on "W AR OS ' A 0*a *oi Support; System far Optimizing Monitoring ^ans'. J J A?jz, M I nr. H S Rifai, G J Nbw*II, and J R GcthIbs.
Grotwid LA'ahs-r, 41i;3 i:i55-i6?, 2003.
Evaluation Date:
rao ilfty fame
Conducted By:
Job ID:
Source Area B2 and BL^Zonfls
Cared rtucrrf-
ConcMTtration Unite:
us'L
SjruplinaPcint ID:l Z2DP|BZ| I ZTDOtBJI | 35DD |BJJ | 3SDDD(B3|T
CtofViciBnt ef Variation:
Mann Randall Statistic |S|.
CMifWence Factor:
CcncTOilraiinn Trcnrl ¦
UfSCi/UWtff. J hv GS'.fWanrr-Ke.!iu'h[i .'cofr! ;a avaiCrc.fc bs is'. CxttK&rObie ewe has J&eerr t/.VKus&j m pftparmy ASs w.,ln,a«' prubW. fajwtvtf JIO Marly, incixfttff vuHmxjI
Ani'lsLcc GSl twvvrmerdaifrx.. maties any .Trprrr«r.«i»h:f: c.« wufjxrdy reganta^ fix tfrcuwy csvrpafaeffs. iv cp.^.Wcw^ u! Uip tnnwstfbw.' contained fxtvv" and" mc sucft
p&rt/ibab 6e toble fa any dteer .viaVerf, Moaettuit&a!. jwcflfcrtfeJ oc atfiar cesuifojr .from Die i*se of this pmAxf & die jwtforoafofl contaiiwd fter&w si-or? in
i>us ,oul&lraAprr *5 sucjeci io nHanpp fcrttobf mdfcp GSfEtwipximenhft (nr., dfcrAnms any respsns&iity or sifgariwr to bvctaie iH? vi^niaA'DiT cwifa.npffViTP.rwa
¦.'•'li bi^V'Si^l!?1 '¦'V., H+Mt'-iid-'V! '. V"1
Figure B-10. Mann-Kendall Statistics for TCE in B2 and B3 Zone Wells in the AMD
Source Area.
70 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
1-Cct-U
1 Get 13
1.15
¦HHH
~.16 1MB I
1 0.53
¦¦¦
-33
¦DB
m
>99,9Kfc |
39,5%
I .BftMS I M.SSS I
mm
Decreasing |
Decreasing
jprob. OoCTE5ising| Prob. Inopcnsing|
| Ocsrcaiirg
SmpCg Sapling
Ewnl r>nte
—15S(A>
—«-27£{A>
-*-293 ?ll are requlrec for saBulatne :ie tier d. yeitiodoxicy .is ta.Vtf tor •) no 40 asnwsi.
1. Con'icleneeinTren d - ConMenss (In a«"ceiiti that consul enteoiKenfallcn Is increasing (5»0i o-decreasing >:s-Ci - Increasing or Cicreashe;
> 93% - PrnbaHy Increasing dt Prabahty Decreasing, ¦ 60!X and S>D - 4a Trend. < £0%. SiO, a nd CCV '±1 = K a Trend; ¦- 9]% and CQV *-1 ~ Sbble.
3. t/eiharinlcgy basnd an 'MAROS: A Dnrisier Stjppart Synhsni fnr Optimo™ g Manitry-ing P1anr„". J .1 Aziz. M Ling. H S Rrfni J Nrrv.cll, nnrt . Ft Gnnj^iler..
Ground Atolrr. 41 i3) 355-"367. 2C03
UfSCLflHSlzti. The (jiSi* iWaxr-tft-mArf TooJ&l is Siw.'Aitie? iiSr-jUiTtfersd'fe GAf? JitfS Gesrrr esefmedtr: p.'tuMCc'j tlur sy'Afcwe LM'.ju'ljuJ, hwstr, r>5 p&tf, VIak>AVi-y* h'aV>sca!
Jtinihffor.' G3)tr^vofX/Kfjiffii~n\, .v. Kkej arry rs^esprrftfAiinr Of dwratrfjrrfcgwlAiry the ifixurKy cimffefaeSs, orcurnpfeSerjessru/ff.* .v'AjrmaiV'i L^.'ilHL'ieu Nrrfy', or.icS.rfr suiVj
iVivArecr. coutssguerfaii itiijlav'ifb.'iir,^,WLi1j,w>.re' rv.'iiitiif.Viiffl iViv as*o/ihwuKMiBianfte rnfismtfltMn MflisitWJiwwt. Wvrtij^inrill
iius piitirftlrci; is sabjeci rc ctotnge wrifaul mp&'re. GS.1 i'ir.o.n:iv.t-tr.'i?i' k>:., ijSjsc.tatms any tvsponsibitif or obigaiiar? k Lf aaiv [tre iirftirarpiTc.n contained hsmir.
Oil 'VI
Figure B-ll. Mann-Kendall Statistics for TCE in AMD Upgradient Wells.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ 71
-------
TRW Microwave Site
The groundwater monitoring program at the TRW Site consists of two components: 1)
evaluation of the non-pumping condition; and 2) semi-annual groundwater monitoring to
assess the EAB program. Three chemical contaminants of interest at the TRW Site are TCE,
cDCE, and vinyl chloride, all of which are currently exceeding current ROD cleanup levels. Freon
113, a fourth chemical contaminant of interest at the Site, is present at deeper level within the
aquifer and is utilized as a tracer for co-mingling plumes from the Signetics Site.
Contaminant migration assessment was conducted by reviewing groundwater contaminant
trends. Wells were selected for Mann-Kendall statistical trend analysis that were in the central
portion of the contaminated areas and were either upgradient, directly downgradient of the
source area or at the down- or cross-gradient property boundary with the Signetics Site. Each
aquifer zone is evaluated separately then an overall assessment will be discussed.
IFfiFHn
# £QNt A MI.1W JOHINCj MfcLl
¦ 4R3UE5PUUJF® BJCIRQIKS (FHLUPSI3TE MCNrrQFW-G WELL
C ocu 4 5IQNEIK5 SITE MOMITOWNQ WELL
, INDICATES Wt»TE»UEVra. ELEVATION W ZONE A
MQWrOfllNC WELL .FEET M3L|
I KM GATES APPFSQ XJMATE FOTEMTIOMETRKI
ftURFAff C-QHTOijR M ?IINF A
WPRQMMATE groundwater flow erection
LOW PEHMEABIUTY IWCWL
MSL MEAN SEA LEVEL
NOT SURVEYED
T-22A IS NOT SURVEYED.
LOCATION IS APPROX9MATE.
FctersMiKfK Suttee CwmjrMat
/cm*.A llcJnfc«i?KW
Mr-tll rnf liicmni
r«*nsr 'HP» IIUOIHPf Srtf
llBMilifrH
Sunr^vite CUfcma
jce
1
tm
3
Figure B-12. TRW A Aquifer Zone Hydrostratigraphic Units showing channelized
flow patterns and groundwater contours (Source: GES, 2024).
The TRW Site is located directly down-gradient of the AMD Site and the eastern portion of the
Signetics Site. The TRW Site is also upgradient from the AMD 915 DeGuigne Drive Site (AMD
915 Site). The groundwater flow directions for the A, Bl, and B2 zones at the TRW Site range
from the south to the north-northeast. However, the hydrostratigraphic units within the aquifer
nT-
T 13A
•* 1
' SOCSA
|34.2€)
S074Ar^
<32. U*
T-2IA
DO'
72 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
zone can also modify the flow pathway on a local scale (Figure B-12). Recent data is presented
in Table B-2.
A Zone
In A Zone wells, Mann-Kendall analysis (Figure B-15) indicates TCE concentrations are mixed,
decreasing (T-7A and T-9A), increasing (T-14A), or stable (T-16A). It is important to note that the
locations with the greatest concentrations are at the upgradient well (T-7A) and the
crossgradient well S005A (Figure B-14). Groundwater concentrations at the Site remain above
the ROD cleanup levels.
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
73
-------
Table B-2. Recent TRW contaminant concentrations in groundwater (October 2023).
Well
Zones
Contaminants of Concern1 (ug/L)2
PCE
TCE
UJ
u
Q
IN
*H
Vt
u
trans-l,2-DCE
u
>
VDl-T'T'T
1,1-DCE
1,1-DC A
CDM
Freon 11
Freon 12
Freon 113
BFM
1,2-DCB
CBN
Drinking Water
Standard3
5
5
6
10
0.5
200
6
5
100
150
NE4
1200
100
600
70
T-1A
B1
Per RWQCB5 approval, the well was abandoned in February 2004.
T-2A
B1
Per USEPA approval, the well was abandoned in November 2014.
T-3A
B1
Per USEPA approval, the well was abandoned in November 2014.
T-6A
B1
Per RWQCB approval, the well was removed from monitoring program in 2009.
T-7A
A
1.4
130
39
1.6
ND<0.56
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-7A7
A
1.5
140
43
1.6
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-8A
A
0.97 J8
69
17
1.5
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-9A
A
0.91 J
53
93
2.6
0.81
ND<1
0.62 J
0.39 J
ND<2
ND<10
ND<5
ND<10
ND<5
2.7
ND<1
T-13A
A
0.96 J
69
23
1.6
3.7
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-14A
A
0.67 J
31
23
1.9
21
ND<1
ND<1
0.46 J
ND<2
ND<10
ND<5
ND<10
ND<5
2.1
ND<1
T-15A
A
1.6
84
27
2.3
ND<0.5
ND<1
0.56 J
0.36 J
ND<2
ND<10
ND<5
ND<10
ND<5
0.99 J
ND<1
T-16A
A
1.3
75
35
2.1
ND<0.5
ND<1
0.42 J
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
1.2
ND<1
T-17A
A
0.90 J
48
14
0.86 J
5.4
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-19A
A
ND<1
1.3
14
1.3
18
ND<1
ND<1
0.39 J
ND<2
ND<10
ND<5
ND<10
ND<5
0.99 J
ND<1
T-23A
A
0.67 J
56
9.0
0.86 J
4.3
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-25A
A
1.6
67
19
1.4
5.6
ND<1
0.44 J
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
1.4
ND<1
36S9
A
1.6J+
49
12
0.69
1.2
ND<0.5
ND<0.5
ND<0.5
NA
NA
NA
ND< .5
NA
ND<0.5
NA
36D9
A
ND<0.5
9
52
3.1
1.2
ND<0.5
ND 0.5
ND<0.5
NA
NA
NA
ND<0.5
NA
ND<0.5
NA
37S9
A
ND<0.5
31
9.1
ND<0.5
0.66
ND<0.5
ND 0.5
ND< 0.5
NA
NA
NA
0.60
NA
ND<0.5
NA
38-S
A
1.0
51
35
ND<1
1.0
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
S005A9
A
2.6
190
100
1.6
ND<0.43
ND<0.36
0.70 J
ND<0.34
ND<0.37
ND<0.75
NA
5.9 J
ND<1.9
ND<0.26
ND<0.26
S074A9
A
ND<0.4
0.60 J
13
1.1
59.0
ND<0.36
ND<0.42
ND<0.34
ND<0.37
ND<0.75
NA
ND<2.5
ND<1.9
ND<0.26
ND<0.26
S079A9
A
ND 0.4
37
3.9
ND<0.42
ND<0.43
ND 0.36
ND< 0.42
ND<0.34
ND<0.37
ND<0.75
NA
ND<2.5
ND<1.9
ND<0.26
ND<0.26
Eductor
A
Per USEPA approval, the Eductor was abandoned in November 2014.
74 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Well
Zones
Contaminants of Concern1 (ug/L)2
PCE
TCE
UJ
u
Q
IN
*H
Vt
u
trans-l,2-DCE
u
>
VDl-T'T'T
1,1-DCE
1,1-DCA
CDM
Freon 11
Freon 12
Freon 113
BFM
1,2-DCB
CBN
Drinking Water
Standard3
5
5
6
10
0.5
200
6
5
100
150
NE4
1200
100
600
70
T-1B
B1
Per RWQCB approval, the well was abandoned in February 2004.
T-2B
B1
Per USEPA approval, the well was abandoned in November 2014.
T-4B
B1
ND<1
3.7
530
2.8
19
ND<1
2.0
0.37 J
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-5B
B1
3.7
1,000
63
1.2
ND<0.5
ND<1
1.5
0.34 J
ND<2
ND<10
ND<5
140
ND<5
ND<1
0.47 J
T-5B7
3.3
1,100
61
1.0
ND<0.5
ND<1
1.5
0.34 J
ND<2
ND<10
ND<5
120
ND<5
ND<1
0.43 J
T-7B
B1
0.60 J
200
11
1.4
0.74
ND<1
0.65 J
0.45 J
ND<2
ND<10
ND<5
5.5 J
ND<5
1.4
ND<1
T-7B7
0.53 J
180
10
1.3
0.60
ND<1
0.77 J
0.46 J
ND<2
ND<10
ND<5
5.0 J
ND<5
1.2
ND<1
T-8B
B1
ND<1
23
460
6.0
12
ND<1
2.1
0.84 J
ND<2
ND<10
ND<5
ND<10
ND<5
5.3
ND<1
T-9B
B1
Per USEPA approval, the well was abandoned in November 2019.
T-10B
B1
0.51 J
39
150
3.3
57
ND<1
0.71 J
0.69 J
ND<2
ND<10
ND<5
ND<10
ND<5
3.7
ND<1
T-17B
B1
0.72 J
180
240
1.9
0.78
ND<1
1.1
ND<1
ND<2
ND<10
ND<5
4.5 J
ND<5
ND<1
ND<1
T-18B
B1
ND<1
ND<1
ND<1
ND<1
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-19B
B1
ND<1
59
1.9
ND<1
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5 Fl10
ND<10
ND<5
ND<1
ND<1
T-20B
B1
ND<1
250
410
4.9
7.3
ND<1
3.9
0.90 J
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-21B
B1
ND<1
390
290
2.3
1.8
ND<1
1.8
ND<1
ND<2
ND<10
ND<5
16
ND<5
ND<1
ND<1
T-22B
B1
1.5
82
170
3.8
0.73
ND<1
0.96 J
0.38 J
ND<2
ND<10
ND<5
ND<10
ND<5
2.1
ND<1
T-23B
B1
1.1
72
160
3.5
0.61
ND<1
0.93 J
0.38 J
ND<2
ND<10
ND<5
ND<10
ND<5
2.4
ND<1
T-24B
B1
ND<1
54
120
1.2
5.2 F1
ND<1
1.6
0.48 J
ND<2
ND<10
ND<5 Fl
ND<10
ND<5
ND<1
ND<1
T-25Bd
B1
5.9
400
100
1.8
1.0
ND<1
2.1
0.38 J
ND<2
ND<10
ND<5
4.3 J
ND<5
2.4
ND<1
T-25BS
B1
2.3
170
420
5.9
9.8
ND<1
3.5
0.64 J
ND<2
ND<10
ND<5
ND<10
ND<5
0.99 J
ND<1
S005B19
B2
1.5
720
710
4.6
ND<0.43
ND<0.36
1.3
ND<0.34
ND<0.37
ND<0.75
NA
16
ND<1.9
ND<0.26
ND<0.26
S073B19
B2
ND<0.4
5.3
250
4.1
150
ND<0.36
ND<0.42
0.55 J
ND <0.37
ND<0.75
NA
ND<2.5
ND<1.9
ND<0.26
ND<0.26
S074B19
B2
ND<0.4
1.7
4.0
1.5
30
ND<0.36
ND<0.42
ND<0.34
ND<0.37
ND<0.75
NA
ND<2.5
ND<1.9
ND<0.26
ND<0.26
S111B19
B2
ND<0.4
500
100
1.2
ND< 0.43
ND<0.36
0.61 J
ND<0.34
ND<0.37
ND<0.75
NA
10.0
ND<1.9
ND<0.26
ND<0.26
T-2C
B2
Per USEPA approval, the well was abandoned in November 2014.
T-10C
B2
ND<1
260
1,100
8.9
10
ND<1
6.6
ND<1
ND<2
ND<10
ND<5
140
ND<5
ND<1
ND<1
T-11C
B2
ND<1
120
7.1
ND<1
ND<0.5
ND<1
0.62 J
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 75
-------
Contaminants of Concern1 (ug/L)2
Well
Zones
PCE
TCE
UJ
u
Q
IN
*H
Vt
u
trans-l,2-DCE
u
>
VDl-T'T'T
1,1-DCE
1,1-DCA
CDM
Freon 11
Freon 12
Freon 113
BFM
1,2-DCB
CBN
Drinking Water
Standard3
5
5
6
10
0.5
200
6
5
100
150
NE4
1200
100
600
70
T-11C7
B2
ND<1
110
6.8
ND<1
ND<0.5
ND<1
0.63 J
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-12C
B2
ND<1
1.7
0.84 J
ND<1
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
36DD9
B2
ND<0.5
0.8
14
7.0
16
ND<0.5
ND<0.5
ND<0.5
NA
NA
NA
ND<0.5
NA
ND<0.5
NA
T-9C
B3
ND<1
ND<1
ND<1
ND<1
ND<0.5
ND<1
ND<1
ND<1
ND<2
ND<10
ND<5
ND<10
ND<5
ND<1
ND<1
T-8D
B4
Per RWQCB approval, groundwater sampling of well was suspended in 2002.
1,1,1-TCA = 1,1,1-trichloroethane cis-l,2-DCE = cis-l,2-dichloroethene CDM = Chlorodibromomethane/Dibromochloromethane
1,1-DCA = 1,1-dichloroethane trans-l,2-DCE = trans-l,2-dichloroethene Freon 11 = Trichlorofluoromethane PCE = Tetrachloroethene
1.1-DCE = 1,1-dichloroethene BFM = Bromoform Freon 12 = Dichlorodifluoromethane TCE = Trichloroethene
1.2-DCB = 1,2-dichlorobenzene CBN = Chlorobenzene Freon 113 = l,l,2-trichloro-l,2,2-trifluoroethane \/C = Vinyl Chloride
2 ug/L = micrograms per liter
3 Drinking water standards are Maximum Contaminant Levels (MCLs) as established by the California Department of Health Services, or if no California MCLs have been
established, then EPA MCLs were used. Concentrations reported above MCLs are shown in bold.
4 NE = Not Established
5 RWQCB = California Regional Water Quality Control Board - San Francisco Bay Region
6 ND< = Not Detected at the indicated laboratory reporting limit shown.
7 Field Duplicate Sample
8 J = Result is less than the RL but greater than or equal to the method detection limit (MDL) and the concentration is an approximate value; H = sample was analyzed outside of
hold time for analyte.
9 Data provided by Advanced Micro Devices, Inc. (AMD) or Philips Electronics (Philips)/The Companies Offsite Operable Unit (OOU).
10 F1 = Matrix Spike (MS) and/or Matrix Spike Duplicate (MSD) recovery exceeds control limits.
76 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
EAB Pilot Injection Oct-OO
HRC Injection Jun-01
Cheese Whey Injection Sep-07
Bioaugmentation event Nov-07
Cheese Whey Injection Dec-07
Cheese Whey Injection Mar-07
Cheese Whey Injection Jun-07
EVO injection in Eductor Oct-10
Neat Vegetable Oil in Eductory
Nov-10
EHC-L Injection Nov-11
EVO injection Dec-14
Source Area Excavation Nov-14
T-2A
T-7A
T-8A
T-9A
T-13A
T-15 A
T-16A
-------
1.2
ND<0.5
VC ND<0.50
Freon 113 ND<10
Notes:
Concentrations are reported in micrograms per liter (ug/L).
Concentrations above California Maximum Contaminant Levels
(MCLs) or federal MCLs are shown in bold.
ND<# - Analyte was reported as Non-detect (ND) for the indicated
reporting limit.
J - Laboratory qualifier, indicates result is less than the Reporting
Limit but greater than or equal to the Method Detection Limit and
the concentration is an approximate value.
TCE - Trichloroethene
cDCE - cis-1,2-Dichloroethene
VC - Vinyl Chloride
Freon 113- 1,1,2-trichloro-1,2,2-trifluoroethane
Dup - Field Duplicate
NS - Not Sampled
NA- Not Analyzed
'Analytical Results Provided by AMD, Phillips, or OOU & Signetics
RICIO AVE.
Freon 113 ND<10
Freon 113 ND<10
Freon 113 ND<10
Freon 113
T-15A
10/9/23
36D*
10/10/23
VC ND<0.50
Freon 113 ND<10
1.2
ND<0.5
Freon 113
T-9A
10/10/23
T-13A
10/10/23
SUBMICROV
DEVELOPMEN
CENTER
/
Freon 113 ND<10
Freon 113 ND<10
S074A*
11/20/23
T-7A
10/10/23
i-0 VJ34B1
VC ND<0.50
Freon 113 ND<10
Freon 113 ND<2.5
JMIDBIt
S071B1
T-16A
10/9/23
37S*
10/10/23
Analytical Results Map
ZoneA- October 2023
PHILIPS
VC ND<0.50
Freon 113 ND<10
Freon 113
Northrop Grumman
Former TRW Microwave Site
825 Stewart Drive
Sunnyvale, California
;OM29B1
T-17A
10/11/23
T-23A
10/9/23
S005A*
11/10/23
S079A*
11/9/23
Drawn
JDB
Designed
DMC
Approved
JKC
Date
11/20/23
Figure
Scale In Feet (Approximate)
ND<0.43
ND<0.43
Freon 113 ND<10
Freon 113 ND<10
Freon 113 ND<10
Freon 113 ND<2.5
Gi oundwstei &Enviionmental Seivices, i
Jd
CD CD
BM
p CD §=J
K3
T-8A
10/11/23
TCE
cDCE
T-25A
10/9/23
TCE 67
cDCE 19
T-14A
10/10/23
TCE
cDCE
31
23
36S*
10/10/23
TCE 49
cDCE 12
Legend
~ ZONE A MONITORING WELL
¦ ARQUES/PHILLIPS ELECTRONICS (PHILLIPS) SITE MONITORING WELL
~ OOU & SIGNETICS SITE MONITORING WELL
OSITE BOUNDARY
Figure B-14. October 2023 Chemical Contaminant Results for TRW Zone A within the Shallow Aquifer. (Source:
GES, 2023).
78 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date:
Facility Name:
Conducted By:
27-Mar-24
TRW
A. Provow
Job ID
Constituent:
Concentration Units
A Zone
TCE
ug/L
Sampling Point ID:| T-7A | T-9A
T-14A
T-16A
Sampling
Event
Sampling
Date
TCE CONCENTRATION (ug/L)
1
Oct-12
63
50
0.96
68
2
May-13
4.2
3
Oct-13
240
67
2
94
4
Apr-14
4.1
5
Oct-14
230
70
3.6
97
6
Jun-15
220
38
7
Oct-15
170
69
23
8
May-16
140
56
20
9
Oct-16
190
64
23
52
10
Oct-17
160
48
55
59
11
Oct-18
140
48
21
69
12
Oct-19
170
40
57
13
Oct-20
110
31
39
54
14
Oct-21
95
48
29
54
15
Dec-22
110
34
26
79
16
17
18
19
20
Mann-Kendall Statistic (S):
Confidence Factor:
Concentration Trend:
1000
£
O
c
Q>
O
C
O
o
11/10 04/12 08/13 12/14 05/16 09/17 02/19 06/20 10/21 03/23 07/24
Sampling Date
Notes:
1. At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2. Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
£ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, SsO, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI Environmental Inc., www.gsi-net.com
Figure B-15. Mann-Kendall Statistics for TCE in A Zone Wells at the TRW Site.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 79
-------
B1 Zone
In B1 Zone wells, TCE concentrations have mostly remained stable but elevated above the
remediation level during the review period (Figure B-16). Sampling results from B1 Zone wells
showed that 18 out of 19 wells had concentrations of one or more constituents exceeding
cleanup levels (Figure B-17). Mann-Kendall analysis indicates concentrations are stable in
upgradient and cross gradient wells (T-7B and T-17B). Trends for wells directly downgradient
from the source area (T-8B and T-10B) show no trend or are stable, respectively (Figure B-18).
80 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
EAB Pilot Injection Oct-QO
HRC Injection Jun-01
Cheese Whey Injection Sep-07
Bioaugmentation event Nov-07
-Cheese Whey Injection Dec-07
Cheese Whey Injection Mar-07
Cheese Whey Injection Jun-07
EVO injection in Eductor Oct-10
Neat Vegetable Oil in Eductory
Nov-10
EHC-L Injection Nov-11
EVO injection Dec-14
Source Area Excavation Nov-14
T-2B
T-4B
T-7B
T-8B
T-9B
T-10B
T-17B
T-25Bs
T-25Bd
-------
T-25Bd
CP
T-25BS
10/11/23
10/9/23
TCE 400
TCE 170
cDCE 100
cDCE 420
VC 1.0
CO
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date:
Facility Name:
Conducted By:
27-Mar-24
TRW
A. Provow
Sampling
Event
Sampling Point ID:[
T-7B (HSU1) I T-10B (HSU1) I T-17B(HSU2) I T-8B(HSU3|T
TCE CONCENTRATION (ug/L)
1
Oct-12
170
50
310
25
2
May-13
120
3
Oct-13
150
17
130
36
4
Apr-14
55
5
Oct-14
170
45
75
10
6
May-15
140
230
5
7
Oct-15
72
31
280
1.2
8
May-16
21
180
4.4
9
Oct-16
21
0.5
190
0.84
10
May-17
160
11
Oct-17
190
17
210
10
12
Oct-18
54
2.8
170
18
13
Oct-19
160
31
150
15
14
Oct-20
64
34
160
7.6
15
Oct-21
130
22
160
18
16
Dec-22
140
29
120
18
17
18
19
20
Coefficient of Variation:
0.43
0.60
0.41
0.78 | I
Mann-Kendall Statistic (S):
-17
-8
-11
2
Confidence Factor:
83.2% I 68.1% I 68.7%
52.4% |
^¦
Concentration Trend:
Stable
Stable
Stable
No Trend
Sampling Date
0.1 1 1 1 1 1 1 1 1 1
11/10 04/12 08/13 12/14 05/16 09/17 02/19 06/20 10/21 03/23 07/24
—T-7B (HSU1)
"•"T-1 OB (HSU1)
—*-T-17B (HSU2)
—m—T-8B (HSU3)
Notes:
1. At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2. Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
£ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S<0, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI En vironmenta I Inc., www. gsi-net. co m
Figure B-18. Mann-Kendall Statistics for the TCE in B1 Zone Wells in the TRW
Site.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 83
-------
B2 Zone
In B2 Zone wells, TCE concentrations have mostly remained stable but elevated above the
cleanup level during the review period (Figures B-19, B-20). Mann-Kendall analysis supports the
observation that concentrations are stable (Figure B-21).
Achieving RAOs at TRW Site will remain a challenge with the persistent migration of VOCs from
upgradient sources, as indicated by data from monitoring wells T-5B, T-7A, T-7B and T-20B.
84 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
EAB Pilot Injection Oct-OO
HRC Injection Jun-01
Cheese Whey Injection Sep-07
Bioaugmentation event Nov-07
Cheese Whey Injection Dec-07
Cheese Whey Injection Mar-07
Cheese Whey Injection Jun-07
EVO injection in Eductor Oct-10
Neat Vegetable Oil in Eductory
Nov-10
EHC-L Injection Nov-11
—EVO injection Dec-14
Source Area Excavation Nov-14
T-2C
T-10C
T-11C
T-12C
-------
Till
I rJ
c
l" • i:
- r
«>»¦*• i
i1
i
^h" '¦ n
T-11C
TCE
120
cUCb
7.t
vc
ND-^.50
FTeon 113
ND<13
j.-K
T
1 |:t
T-1 DC
10J&2
sso
cDCE
1,100
W
10
Frr.m 11 ?.
li.1
— , I
3600*
wnouFa
TCE 0.83
cLJCb 14
VC 19
FftfO i -1? ND--0j5C
T-12C
10ld 0/23
TCIF 1 7
cDCE 0.94 J
vc m-vot.
FrsoT13 HD
CwiwnlrSUcfi* «b:lr.n!Hrl
report ngli-t
J - jto-aici? qu^J licr. rdcxss rrsil rc te-s* Fran t*w "te^c-lina
L rlt but £r±a:cf Ihsn jr equal Ic-lfiL F/ofl-ot Ddtglcc JmK and
I'm dll M|jpi :.i.cj|IIHl« VBVHf
I C_ - I nittcraft-ie^e
(iDriF - c ft-i .T-n&i r.f iml'iHriH
VC - Vinji ChI-jr dc
Krcxi 113 1.1 trttf-lcro' ,2.2 t Tutxacnatc
HA - Hi:-I « ihIj,.--h:I
"Analy:<03l Resutt Provided by AMD, -hilips. xOCU » £innelis%
V
r
r i
u
•*-n2s&
Kcitf pcp^rji «n
"cm* r ft'. Mrixwah&li
305 £tr/r:Dri*C-
£imf#a i", I jI Uiitm
JOi
~ v yw
nwfc
**7—4
MZ
riAir-i
i«» ¦«
D
•J. A' 1 ¦«.l .•¦I.'- »
rj -rim
CLEJfS
Figure B-20. 2024 Chemical contaminant results for TRW Zone B2 within the Shallow Aquifer.
86 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
ug/L
Sampling Point ID:| T-11C
T-12C
Sampling
Event
Sampling
Date
TCE CONCENTRATION (ug/L)
1
Oct-12
290
9.3
2
Oct-13
460
140
3
Oct-14
310
140
4
Oct-15
43
2
5
Oct-16
3
0.5
6
Oct-17
310
140
7
Oct-18
150
99
8
Oct-19
290
140
9
Oct-20
250
120
10
Oct-21
200
1.9
11
Dec-22
270
29
12
13
14
15
16
17
18
19
20
Coefficient of Variation:
Mann-Kendall Statistic (S):
Confidence Factor:!
Concentration Trendil
1000
u> 100
3
C
.2 10
13
k.
5
u *
c
o
o
O.f
-T-11C I
-T-12C
11/10 04/12 08/13 12/14 05/16 09/17
02/19
06/20 10/21 03/23
07/24
Sampling Date
Notes:
1. At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2. Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
> 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S<0, and COV > 1 = No Trend; < 90% and COV < 1 = Stable.
3. Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41 (3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, conectness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI Environmental Inc., www.gsi-net.com
Figure B-21. Mann-Kendall Statistics for TCE in the B2 Zone Wells at the TRW
Site.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 87
-------
Signetics and Offsite OU
Although VOC concentrations within the OOU during the current Five-Year Review period are
lower than they were in the Five-Year Review period that ended in 2019, data from the last five
years indicate that the OOU has not substantially progressed towards reaching the RAO of
groundwater restoration. Dissolved concentrations of TCE, cDCE, and vinyl chloride exceeded
MCLs in one or more zones of the shallow aquifer across the Site and discussion about the OOU
TCE plume is primarily based on data from extraction wells, set between about 600 and 900
feet apart and installed between 1988-1992, along residential streets. The lack of data between
these extraction areas makes inferences of the internal characteristics of the TCE plume difficult
and likely affects the ability to determine a proper remediation strategy.
Furthermore, there continues to be a gap in the detail and accuracy of the CSM for the OOU
Site that is affecting the aquifer restoration. The CSM needs to be updated to incorporate the
preferred transport pathways of the fluvial depositional environment known to exist in the
region. Updates to the CSM should include the following activities: regional pre-remediation
hydraulic gradients should be estimated; a detailed review of lithologic changes from boring
logs; permeability zones should be identified including thicknesses; detailed cross-sections that
map high permeability zones; and new subsurface chemical and stratigraphic data should be
assimilated where appropriate.
Groundwater flow direction is to the north-northeast (Figure B-22) for the shallow aquifers (A
and B zones). Elevated TCE concentrations in shallow groundwater continues to be a source for
vapor intrusion into residences and schools above the dissolved TCE groundwater plume.
Based on data presented in the 2022 Annual Monitoring Report, the remedy appears to be
providing some horizontal hydraulic control of contaminant migration in groundwater.
Comparison of the 2010 TCE plume (Figure B-23) and 2022 TCE plume (Figure B-24) in the A
zone shows that the footprint of the plume has not significantly changed, and containment
appears to be occurring.
Currently, additional sitewide investigation is being conducted to better define the A and B1
aquifer plume (Figures B-24 and B-25) and address data gaps. The investigation includes the
outside northern Site boundary above Lakehaven Drive and areas between Duane and Alvarado
Avenues. Estimates for restoration times (Figures B-26, B-27, B-28) have not improved since the
last Five-Year Review and continues to be decades past the ROD-estimated projected
restoration time of 2027.
88 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
The GWETS for the Offsite OU is generally maintaining plume control; however, improvements
are needed in the remedial strategy to reduce the footprint of the groundwater VOC plume and
reduce timeframe to achieve RAOs. For that purpose, a focused feasibility study in the OOU is
needed.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 89
-------
CO J hps raw Id
7uJknL-aCK]55 fl/ff
r[2a-22)/91Sl
mm; eruyeiemn
Arquuu hyCrodfe
A ycilrtr
D.&OflO ft/it
K+^35}/&30]
"A" MUFTR
K22 AWMliAL SfiCllHWIfftH ELEVAH3H CDHTOJRS
OCTTDBEH 2M3
r.iyjrnr^: ste
,W OTSTE DPESWBLI LW
SLWfWLE, Oy_FGRKlA
Figure B-22. A Zone Water Elevation Contours for the Offsite OU and Nearby
Sites in October 2022.
90 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
• MONITORING WELL
• EXTRACTION WELL
A PIEZOMETER
APPROXIMATE OPERABLE UNIT BOUNDARIES
COLOR INDICATES WELL OWNER/SITE:
• PHILIPS SEMICONDUCTORS (FORMERLY SIGNET1CS)
• AMD 901/902 SITE
• raw MICROWAVE SITE
AMD 915 SITE (INCLUDES P-WELLS)
5TTE OPERABLE UNIT
TCE CONCENTRATION (mg/L)
DENOTES NOT DETECTED A30VE THE
DETECTION UMIT SHOWN
TCE CONCENTRATION CONTOUR (mg/L)
DENOTES WELLS NOT SAMPLED
-J f
"A" AQUIFER
TCE CONCENTRATION CONTOURS
FOURTH QUARTER 2010
THE COMPANIES OFFSITE OPERABl.E UNIT
SUNNYVALE, CALIFORNIA
PREPARED FOR
PHILIPS
ELECTRONICS
ISSUE / REVISION
a I 27-006-E361
-------
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4- T^st «M< jrfUMi wjJH.fi W*®« *T iiia
T« **rai v*uk is iju ro« ronturwc.
s. aw; 915 wo jjw hi/kb vrt otwtwh mi o«n
-44 FTJftjErfti MM mMML UCMTCAr.:
«j"QW3 JT OT1CJ-:.
'A' A5UFER
2C2Z AMHLM. TCE OUMCENTWnCW COiTHJFS
rflUflW ouw™ 2022
3CNE7KS 5JTE
«C OFTWE OFEPABLE UMT
SUCALIFCRNA
Figure B-24. 2022 TCE Concentrations A Zone.
92 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
Locus
N/N/' TECHNOLOGIES
REFERENCES:
1. MONfTORWG WELL REPORT TOR LOCUS TECHNOLOGY AT
THE OOU AND SIGNET1CS WELL SfTES IN SUNNYVALE,
CALI FORMA DATED DECEMBER 20, 2018 AND PROVIDED BY
CROSS LAND SURVEYWG, INC. AOOmONAL WELL LOCATIONS
SURVEYED BY CROSS LAND SURVEYING, INC., WOL AND WELL
PONT REPORTS DATED SEPTEMBER 11, 2020 AND DECEMBER
11. 2020.
2. UNEWORK FROM SANTA CLARA COUNTY INFORMATION
SERVICES DEPARTMENT AND THE ASSESSORS OFFICE,
C0UNTYW1DE GIS MAP DATA AVAILABLE TO COUNTY DEPARTMENT.
ITS PARTNERS AM) THE PUBLIC AND THE CITY OF SUNNYVALE.
CAUFORMA GtS DATA. COPYRIGHT 2016.
3. SATELLITE IMAGERY U.S.G.S. EARTH EXPLORER™. THE
ORTHOIMAGERY WAS EVALUATED BY THE U.S.G.S. AND MEETS
THE NATIONAL MAP ACCURACY STANDARDS (99* CONFIDENCE).
REPORT DATE JULY 2*. 2015, COPYRIGHT 2018.
4. WHERE THERE WAS DUPLICATE SAMPLES TAKEN AT WELLS.
THE HIGHER VALUE IS USED FOR CONTOURWG.
5. AMD 915 AND AMD 901/902 SHE CONTOURS ARE BASED
ON PUBLISHED 2022 ANNUAL GROUNDWATER MONITORING
REP0RT5 BY OTHERS.
*B1' AQUIFER
2022 ANNUAL TCE CONCENTRATION CONTOURS
FOURTH QUARTER 2022
SIGNET1CS SITE
AND OFFSITE OPERABLE UNIT
SUNNYVALE, CALIFORNIA
Figure B-25. TCE Concentrations B1 Zone 2022.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 93
-------
A Aquifer Restoration Estimate
Well COM39A
IttJU
i
o _
s
5 3:
!
-5
: :xi
ic
¦,V yV
5^ /•
-------
B1 Aquifer Restoration Estimate
Well COMGOB l
Aw///w///////////
Date
B1 Aquifer Restoration Estimate
Weil S077B1
Date
Figure B-27. B1 Aquifer Restoration Estimates for Wells COM60B1 and S077B1.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 95
-------
BZ Aquifer Restoration Estimate
Well COM06B2
1CKXJD
t
a _
n
z
7
10
Remediation Level = 5 [jy/L.
1 1
r-.
irJ
rn
H
r-j
Ui
rr>
L"1
IT"
r-i
Ci
O
r i
r-.
Ci
O
r-j
H
D
rM
r-.
O
r-j
m
O
r'
r-.
rn
D
r i
m
rj
r-.
p-i
O
r-j
P-4
Tf
T± UI
o o
r-j r-i
ji
n
O
r1
r-.
UJ
~
F-
rj
r-.
r_i
r1
-J
Q
-¦J
id
D
r1
JM
L 'i
O
r-j
r-j
Cj
r-i
O
1
7-'
3-J"
fH
-H
i
—i
rH
r—H
f-i
rf
¦nr"
*T
"?
Tr"
"f
rr
rf
¦ir
¦rf -t"
Ddte
rr
rr
7T
rr
¦f
t"
B2 Aquifer Restoration Estimate
Well COM60B2
Date
Figure B- 28. B2 Aquifer Restoration Estimates for Wells COM06B2 and
COM60B2.
96 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
A Zone
In A Zone Mann-Kendall analysis in selected wells (Figures B-29 and B-30) indicates TCE
concentration trend are mixed, no trend (S075A2, T-COM41A and COM05A), increasing
(COM46A, COM55A), decreasing (COM06A) or stable (COMOIA, COM03A, COM04A, COM49A).
B1 Zone
In B1 Zone, Mann-Kendall analysis (Figures B-31 and B-32) in selected wells indicates TCE
concentration trend are stable in well COM03B, increasing in wells S075B and COM50B1 and
have no trend in wellSaCOM63Bl and COM01B1.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 97
-------
Sampling Point ID:
COM01A
S07SA2
COMMA
CDW Z-4A
COMDOA
COMKA
E»ci* Date
T££ GONCENTRAUGN
- :
13
150
12C
24
180
11
T
li-Jscs- 3
29
1.7
11C
25
21D
9-7
3
- -
76
Si
11C
ii
17H
5.4
4
en» is
K
V
13C
25
143
9.3
c
ir-hc^ €
7~>
46
100
22
17D
3
6
2 -f*C^ 7
29
WD
12E
25
133
14
7
=-n: - :
B 9
12D
3€
25
9a
12
e
: -m - i-
20
130
10C
23
1SD
21
s
5-C«-2£
3S
130
10C
25
140
17
1C
¦¦¦: -:
54
51
93
17
11D
14
11
r--.:
57
73
I3C
7T
130
14
12
13
14
1E
ie
17
18
15
2C
CMltKHCfTl cr VsralKn:
O.fiC | *.€7
0.14 | 1.11
12
a.54
llann-Ktfidsil Satistis |3J:
^ 1 4
-It
-13
-3©
24
C&rrtdense =*r!on
63.0* | 6*Jt%
I fl7.SK I 82.1%
ffi.0%
&8.4*
Con Denfratiors Trend:
Stable
No Trad
Stable
StaUe
Denuung
bucjuag
WK
0
1
c
8
£Z
Q
U
0*12 01.'13 11/Tt OATP WfT 0319 MB?
Sampling Date
i«f
03/13
om*
Motec
1. *± east fax iTOTMnOB-t sarrjilhs ewrfc pervwT are rKiired-far cacjsito B» trend .Utfteootocy rs t'a'.ta 'rxi e> 4C arvtez
2. CofifaencE ii Trend - Confbmcc (Si :«"wr: ttiat :c n :t :le*r. concsntriian Ic- rcrsaoia (3>0) sr decreasing iS':'5' cr Wwr damages niu'i'-j ;mm rw usr&ix ro.v" ar rf--5 caroroG'fttran /hiar-aKy n
(ni suiviora; « ssewtilai?! MV-TiaRu ii£I fcrMmnnenJaliK. asstaTC WfrasKraDllv ¦yctt'M&.v (s tcasH fi» jiYartSK*: :>*an»s 1«,r«.
lKI BntMwa/ItiL,
Figure B-29. Mann-Kendall Statistics for ICE in the A Zone Wells at the OOU Site.
98 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date;
Facility Name:
Conducted By:
3-0-Aug-24
Job ID:
Constituent:
Concentration units:
Source Area A Zone
The Companies Offsite OU
TCE
Ma* Williams
Ugfl. |
Sam pling Point ID:
COH43A
COM46A
COM41A
COM05A
I I I
Event
flBfti
ICE CONCENTRATION tp&l)
1
4-Dsc-l 3
31
2
2CH40V-14
2.4
3
25-NOV-U
35
4
6-NOV-15
7.7
2.7
5
14-WM-15
35
6
:
8.3
1.9
7
23-NOV-15
34
8
2HMW-17
€
2
9
4-Dec-17
37
10
3-oct-ia
2.4
11
5-Nov-* 3
8.5
34
12
S-Nov-13
1.7
13
4-Jun-15
1.9
14
lo-Oct-19
2.3
15
1-Nov-19
9.7
27
t6
2-Nov-'9
1.5
17
¦ 1-Dec-13
9.5
18
2-',:
2.5
19
8-lec-:-l
1.9
20
IQ-Dec-20
43
21
9-wU-21
2.9
22
23-OCt-21
2.4
23
ia-NW-21
5.3
33
24
11-NIW-21
2.3
25
28-Jun-22
2.6
25
25-Oct-22
2.7
27
14-NdV-ZZ
7.5
28
• S-N0V-Z2
35
32
29
22-Jun-23
4.6
30
25-Oct-23
5
31
¦ 5-tvCV-23
3
5
32
33
34
35
Coefficient of Variation:
019
0.34
0.12
0.42 I
I J
Man n-Kendal I Statistic (S):
0
27
6
8
1 1
Confidence Factor:
46.0%
9 9.2%
66.8%
72.9%
1 |
Concentration Trend:
Stable
Increasing
No Trend
No Trend
Sampling Date
Notes:
1. At least Ton' independent sampling events par wefl are required tor calculating me trend. Metno;i or decreasing iS-eDJ: >95% - Increasing or Decreasing;
a 9C*i - Prooawy increasing or Probata Decreasing; < KI% and S»G - No Trend; ¦= 90%, SsO, and COV s 1 - No Trend; < 90% and COV •< 1 - StaHe.
3. Methodology D3sed on "MAROS: A Decision Support System tw Optimizing Monltorng Plans", J.J. Aziz, M. Ling, H.S. Rlfai, C.J. Newell, and J R. Gonzales,
Graano Water. 41|3):355-367, 20C-3.
DtSCLA/MER: The GSI Maor^KeoOaS Tootfat c maibMe 'as Coi?-s«fcra!ie ca*e has Oeen exevtsea in preparing ffvs soflwa/'E crocket fioirewr, ,no party, .rwutfng nfrnw!
iXTrarwi GSJ Eni/rorrfnefial inc., mattes any ^•esenrasKi? or ivaTaniy pairing cfre acaracy, avTecirwss, or coi^eKoess tfit>e krfymavon sonared beren antf no suet)
parr/ sftai' ae vx*e fbr any aiect warecc canseayenriai, roderaa1 or c&er darr>ages /esurtng from me use of fits pix^cr or me inrtymaabn ccr&xiea n&eiv. iTfrmaKvi in
c^vs pLttic&on is siiOiecr rc cnange afmcct ramce. GSI En>iw!\en& Ik., oiscJaims aw resoonsinVc/ or cctoaron re jpdais me infofTraiacfi ccrxaveo Herein.
GS.'wnw^kwisOTr
Figure B-30. Mann-Kendall Statistics for ICE in the A Zone Wells at the OOU Site
(continued).
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 99
-------
GSi MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluziicn Oars:
FsiiJity Kairc
C&ndusttd By:
£7-U-ar~24
uCb D:
E1 Zone
The Companlec OffGlte CO
ConsrtmierTt
TCE
A. Pruvow
CMHoentraEKXi Unhs:
ua'L
Sampling Point ID:
COMG1B | SI76E | COM33E | COH&&-B1 |
TCE COICSffTRATION (iugA.|
14-Ncv- 2
11C
3.5
S
32
2
25-NCi- 2
Si
C.5
4€
30
3
2C-Nc%u14
12E
c 2
51
3.7
4
S+iW-15
11C
43
29
c
ic-rv:v- g
11C
1.2
47
23
€
2HVCV- 7
13C
1.0
57
22
7
2-OcME-
79
3.3
4C
23
S
5-CO-1S
12E
320
52
29
c
i-tscs-z:
120
250
5C
30
10
27-OG-21
K
170
45
25
11
25-GC-22
120
550
55
35
12
13
14
15
16
17
1B
1S
2E
Goeftnient ar Variation:
0.1« | 1 SB
0.14
•
451%
2
BJft
Hann-Kendatl wLarisbi |3{:
Oorridense =xnor.
¦m*
87.®*
i
ConwiYxztiorr Trend:
No Trend
increamng | Stable
No Trend
itw -
m I —t— ' I
/ ^ I ¦
-
3
c
0
1
c
i
c
o
o
ja -
1 ¦
at -
_ y | I ^ -^-1' |
04/12 M13 HI* 05T6 <3Vt? OZt} 0S35 1Q7T OWJ 0!%4
Sampling Date
NotBt:
1. ¦tad: fDur ndeoenoert sampirg evert per we! are requted far cacJaflng ttw trend WMtodBfcnF '"s v&ti ftr 4 id 4C aviates.
2. CorfoeTCC n Trend - CorfioercB i n pccefrt; that renrtxen: concefflrat'on Ic feKFcaatog (S»0| or decreasing iS-eOt *9S% - Increasing ^ Decreasng
i 90% - Prafcabfy roeacSTg ty Pntoa&y Decreasing; < SCFK arc S=-C - Hd Trend: * 90%, SsQ, and GOV a 1- NoTnsKt < 90V and GOV «1 - Statte
3. Ktmooocg^ eased y TA^ROS: A Dedsori 3uopcrt Bysfcm far Opcmayig Mentoring Fart:' JJ Aziz, M. Lng. H.£ Rfai CJ. Newell, ard _.R_ Gorzaes,
Gwtf 41(3J355-3G7,2001
1'ijC^AML.H- m» ay Wsrfi tandBfl 'oe#* is mttbta 'as a*. dgnrtiratto :arz ixwi ajfflnwfrtff? .oraMR'^ tos frsftwn prettcr r>:*MW. no party. nokrihg hhWdu1
*aMu S&rtwo^wita .tic, ,ti»ik ary •wwortflrcsn or nrrWy tgorarg Sw accuracy, ccpucirwss >yoGtfpfS*sn«5 a1 fte HonMCto ion*jaw?.baraft a« nc suofi
party stal ba .ts^H tor ary d'&cr GOflMguartia/, /^Cidtofiiaf or error aamajK reaJtog Tern ma uW attte produc! orP^s ntDrmakn oc/Xmn&ihtnln. JrilbCTHftx n
the; pj&catan & sx.wr Jc dhatvp atfbad- iXttM S& I tn^rtsvrwnL*1 he. asatans en k mqpoxiitly or oWpriton to ufarfa ffle rtarrsom :orra nsd
GSI BraKum!*1 .Vm: , nwr^l art-
Figure B-31. Mann-Kendall Statistics for TCE in the B1 Zone Wells at the OOU
Site.
100 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Date:
30-Aug 24
Job ID:
Source Area B1 Zone
Facility Name:
The Companies Offsite OU
Constituent:
TCE
Conducted By:
Max Williams
Concentration Unite:
ng.'L
Sampli ng Point ID:
COM50B1
Event
Sampling
Date
TCE CONCENTRATION (wIL)
1
5-Dee-14
1.3
2
20-Nov-IS
0 9
3
3-Dec-18
0.25
4
10-Dec-17
19
5
5-Nov-18
1.9
6
1-Nov-19
1.3
7
1' -Dec-20
2.4
a
IO-Nov-21
2-5
9
15-Nov-22
3.2
10
16-NOV-23
3.3
11
12
13
14
15
16
17
1B
19
20
Coefficient
of Variation:
0.52 |
i i i i
Mann-Kendall Statistic (5):
33
1 1 1 1 ¦.
Confidence Factor
99.9% |
Concentration Trend:
Increasing |
Sampling Date
Notes:
1. At least four independent sampling events per wei are required for calculating the trend Afetfiodoi'ogy is vaSd for 4 to 40 samples.
2. Confidence1 in Trend = Corrfoence (in percent! that constituent concentration is increase (S>0) or cecreas*Tg (S<0): >95% = Increasing or Decreasing:
2:90% = Probably Increasing or F*rofoafcfy Decreasing < 90% and S>0 = No Trend; < 90%, S£0. and GOV £ t = No Trend; < 90% and GOV < 1 = Stafate.
3. Methodology bases on "MAROS: A Decision Support System for Optimizing Monitorifig Plans', J.J. Aziz, M. Ling. H.S. Rifai, C.J. Newell and J.R. Gonzales,
Ground Water. 41(3Jc355-367. 2003.
DISCLAIMER: The GSI Mano-Kendaff Toolkit is available "as is'. GonsKferafete care has beea exercised in preparing this software product however, no parly, including without
imitation GSI Environmental Inc., mates any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and rw sucfr
early shaV J» fable for any deed, indirect csnsequeflfiat incsfertal or other damages /esiitihg from the use of this prooUet or the information contained nereifn. iRfomsatcn m
tfvs pubiicJtion is subject to change wtrwf notice. GSi Environmental Inc., disclaims any responsibility or obfigaoa'T to update the information contained Herein.
GSi* Bivvwimemaf Inc.. wwt.gsi-neLcom
Figure B-32. Mann-Kendall Statistics for TCE in the B1 Zone Wells at the OOU
Site (continued).
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 101
-------
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
Evaluation Uta:
=a«lrty K aire:
CondusttEl Ey:
27-Mar-24
-ob D:
B2 Zone
The Com oar let Off<e OU
CoiKthuent
TCE
A. Pravow
Conoenlrsci'sn Huh-
ua'L
Ssm^irij P&ht ID:
CGM01B2 | CO u ISE2 | COMQ6ES | COMCBB4 | CQMD8B4 | COMQSB2
IE3
TCE CONCEtfTRADQN (ugTLj
14-fcw-12
15C
190
37C
99
590
510
2
2S-fte*-13
190
-90
34C
95
560
-£50
3
2iH«v-*4
13C
24-0
37E
13D
543
550
4
»5-Ncv-1E
19C
193
34C
55
550
J*0
c
IC-Nov-IE
15C
232
IzC
54
453
J40
€
1 -Nov- 7
21C
252
44C
99
5S3
540
7
2-GdMS
190
EE
27C
59
:-a-3
320
a
15-QGMS
2CC
323
220
52
570
350
s
Hvcv-2E
190
292
4CC
i5
TOO
£00
1C
2"-C-C-_
16C
2*0
190
ii
4CG
540
11
25-QC-22
1=C
23 3
210
-9
390
3=0
12
13
14
1E
16
17
10
15
20
C&enwfefri of VanatKn:
mnr | ».si f qj« | ©.J8
0J!3 J Oil
Mann-Kendafl S-jnsri: |3|:
4
24
-21
-37
-21
-2D
:::>r^d:n:e :wtDr
G6.D*
B*.4%
MM |
W.0K
92.9*
CcnKffntiofl Trend:
Ho Trend
Prab. Decreasing
Decreasiig
Prah.Deoeasiq
Profe. Decreasing
1KW -|
1 1 -4s*C H.
Ij
&
ffltf "
¦ . *¦ ¦ ^ 1
¦ DDWOgP
i CL^Joea:
II ZDMBEBM
0
1
E J (J -
3
c
O
o
) .
««2 am lit* 'ivit Qvu ant i»®? t«t m«j
Sampling Dale
Nc*.k:
1. eKltsj Indeoenaeri sampling f«rt pernwei are requredf:rca!C-Jad*>3 the trend ^tstmtsiogyts vatUtf ftr4 k> 4C aopies.
2. Confttence In Trend - Confidence m perent Itut ccnstfouerB omcenMan I:- rcreasna i S=Kli ordeaeariTg (S<0r --*$'¦>. - Increasing x Decreasing
£ 90% - ncreasnfl or Fraba&i' DecreasfE < 9CR-L and 5>C - 'Sic Trend; -c 90St, S=sC, and CO"-.' £ 1 - No Trend: < 5f£R and GOV < 1 - Stafcie
3. Kfetrtooooflj' Based on "MARCS: A Dedfcon Eusport Syrte-" fa* QoSntzang Mcrfcornj Pan:" J J Aziz, ML Lng H.E RFai. GJ. Ne*el, ard J.R. Gorxaes,
Gwtf tt'Sref, 41ii;c355-5€7,2DQ3-.
IVSGLAMEft' 'w OiSi Mam ?&rvk* !oaM is x L&WiWftbto cart Nss awn ^>»Ti2;^.r\srar«afTr-a rn: ::<*wcrD ptmlct noiwt*r. rra partr rnkxtogi niVko1
4rv!aten sa t'wmwta km, nutae a*y ^'Kft-SBRsc or Hanatiy 'sqcrtl^ 0w accuracf, co"sctn«s crconDrMwiKS a" ff»n^rfltGr1 xa*ar»d ana r>: sicn
paty sftal Da iwsfcta .Vary alrecf mlrxt, oar&vjovHal, trctdcrtAl ontivsr Ajnotf»i: rasufimg .torn ffw use of tftS Erode! ort^s trtixTT&ton ccftan&itenm. .titawahor *i
an is rtcv:£KSf: s sityftJ Jo o^uojh tw*-- .t i-wtoa G&i &MmrOTWTisf hie. itedains an jr ny&tt£A My
OSJ mm.p^mLsm
Figure B-33. Mann-Kendall Statistics for TCE in the B2 Zone Wells at the 00U
Site.
102 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
Appendix C: Applicable or Relevant and
Appropriate Requirements
Assessment
Section 121 (d)(2)(A) of Comprehensive Environmental Response, Compensation, and Liability
Act specifies that Superfund remedial actions must meet any Federal standards, requirements,
criteria, or limitations that are determined to be legally applicable or relevant and appropriate
requirements (ARARs). ARARs are those standards, criteria, or limitations promulgated under
Federal or State law that specifically address a hazardous substance, pollutant, contaminant,
remedial action, location, or other circumstance at a Comprehensive Environmental Response,
Compensation, and Liability Act site.
Changes (if any) in ARARs are evaluated to determine if the changes affect the protectiveness of
the remedy. Each ARAR and any change to the applicable standard or criterion are discussed
below.
Chemical-specific ARARs identified in the 1991 ROD and subsequent ROD Amendments for
groundwater were evaluated (Table C-l).
Table C-l. Summary of Groundwater Chemical-Specific ARAR Changes
Chemical
1991 ROD
Cleanup
Levels (|ig/L)
Basis for Cleanup
Current Regulations (|ig/L)
ARARs More or
Less Stringent than
Cleanup Levels?
Level
State
Federal
1,1-DCA
5
State MCL
5
NA
No changes
1,2-DCB
600
State MCL
600
600
No changes
cDCE
6
State MCL
6
70
No changes
tDCE
10
State MCL
10
100
No changes
1,1-DCE
6
State MCL
6
7
No changes
Freon 113
1200
State MCL
1200
NA
No changes
PCE
5
State MCL
5
5
No changes
TCE
5
State MCL
5
5
No changes
1,1,1-TCA
200
State MCL
200
200
No changes
Vinyl
chloride
0.5
State MCL
0.5
2
No changes
Federal and State laws and regulations other than the chemical-specific ARARs discussed in
Table C-l that have been promulgated or changed in the past five years are described in Table
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 103
-------
C-2. There have been no revisions to laws or regulations that affect the protectiveness of the
remedy.
The following action- or location-specific ARARs have not changed in the past five years, and
therefore do not affect protectiveness:
• EPA Office of Solid Waste and Emergency Response (OSWER) Directive 9355.0-.28
• Bay Area Air Quality Management District (BAAQMD) Reg. 8 Rule 47
• Bay Area Air Quality Management District (BAAQMD) Reg. 8 Rule 40
• Fish and Wildlife Coordination Act
104 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Table 1 iary of ARAR Changes for S st Five Years
Requirement and
Citation
Document
Description
Effect on
Protectiveness
Comments
Recent Amendment
Date
Clean Water Act,
Section 401
1991 ROD
California MCLs are
ARARs for the site
and were used to
establish
groundwater
cleanup levels.
Changes do not
affect
protectiveness.
Under Clean Water Act (CWA)
section 401, Congress provides
states, territories, and Tribes
with a tool to protect water from
adverse impacts that could result
from Federally licensed or
permitted projects. The final
2023 Clean Water Act Section
401 Water Quality Certification
Improvement Rule (2023 Rule)
restores the fundamental
authority granted by Congress to
states, territories, and tribes to
protect water resources that are
essential to healthy people and
thriving communities. The 2023
rule will support clear, efficient,
and focused water quality
reviews of infrastructure and
development projects that are
key to economic growth.
January 1, 2023
Resource
Conservation and
Recovery Act
(RCRA)Land
Disposal
Restrictions
1991 ROD
California MCLs are
ARARs for the site
and were used to
establish
groundwater
cleanup levels.
Changes do not
affect
protectiveness.
EPA is adding hazardous waste
aerosol cans to the universal
waste program under RCRA
regulations. This change will
benefit the wide variety of
establishments generating and
managing discarded aerosol
cans.
February 7, 2020
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 105
-------
Requirement and
Document
Description
Effect on
Comments
Recent Amendment
Citation
Protectiveness
Date
National Pollutant
1991 ROD
California MCLs are
Changes do not
EPA is finalizing a rule revising
November 27, 2023
Discharge
ARARs for the site
affect
and replacing the 2020
regulatory requirements for
Elimination System,
and were used to
protectiveness.
water quality certification under
40 CFR Part 122
establish
CWA section 401 to clarify,
groundwater
reinforce, and provide a measure
of consistency with elements of
cleanup levels.
section 401 certification practice
that have evolved over the more
than 50 years since EPA first
promulgated water quality
certification regulations. EPA is
also finalizing conforming
amendments to the water quality
certification regulations for EPA-
issued NPDES permits.
106 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Appendix D: Public Notice
4 BAY AREA NEWS GROUP 186 FRIDAY. FEBRUARY 9.202 4
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Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OLJ
107
-------
Bs. An official wchsitp of the United States government
Q
News Releases: Region 09
*-http:; f'/epa. gov/r«W5reteases/seafch/pres$_office/regiori-
CS-.VU i*
MENU
CONTACT US
EPA to Review Effectiveness of
Cleanups at 14 Privately-Owned
California Superfund Sites in 2024
February 8,2024
Contact Information
John Senn (serri.jonnfflopa.gov)
415-972-3999
SAN FRANCISCO - The U.S. Environmental Protection. Agency (Ei'A) will perform comprehensive five-
year reviews this yeaf of 14 National Priorities List Superfund privaleiy-owned sites in Ca.tfornia
where cleanup remedies have sc-er implemented, "nc sites will undergo a legally required review to
ensure that previous remediaton efforts continue to protect public health arid the e*w"ronnent.
Once the tive-yearrev'ews are cotolete, the findings wil. be posted to each Superfund site's web
page.
"Reviewing the cleanup work that has occurred at tnese Superfund sites across California is critical to
ensuring that public health and the environment are protected," said EPA Pacific Southwest
Superfund and Emergency Management Division Director Mike Montgomery, ""hese rev ip.w-. ilsc
serve as important ways to deliver information to the public about Superfund sites where pollution
remains and additional work could be neeced,"
The California privately-owed Superfund sites where E3A will conduct five-yea' rev'ews in 2024 are:
• Advanced Micro Devices (Building 915) ^mositfops.govysjpcr'i^dtedvancedmicrodevicesgis* in Sunnyvale
• Farr.hild Semiconcuctor Corporation Soutn San Jose Plant
frf Thilt^n'U ciruJuc1
• Indusitr ul Waste 3rocess-ng in Fresno
108 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
• Midclpfeld-rilis-Whisrran (MTW) Study Area in Mountain
View, which comor'ses three Superfund sites: the fairchild Semiconductor Cora-Mountain View
site, the Raytheon Company site, and the Intel Corp-Mountain View site as well as portions of the
Nava^ Air Station Vlofett Field Superfurd site,
• Palos Vco'es Shelf portion of the Montrose Chemical Corp. site«https://epa,gov/soperfi»d/montros«> in
Torrance
• IeledyiO*hU|>sy/upB.RW/»jper,i.-d/te,ecyw and Spcctra-Physics
sites in Mountain View ijont cleanup and review)
• Triple in Sunnyvale, which comprises the following Superfund
sites: the Acvanced Micro Devices 901-90? Thompson Place site, the TRW Microwave site, and the
Signetics s>te. The Signeticss'te is not part oT'the five-year review becai.se it is no: on the National
Priorities List.
• Valley Wood PreMJfVilg, Inc. ^https^/epa-gov/superfand/valleywocd--- in Tarlock
• Waste D'sposal, Inc. erfaftd/wasfeclisposal> in Santa Fe Springs
Background
Th'oughout c p'ocess of designing and con^UsjeCrig a cleanup at a hazardous waste site, EPA s
srtmary goal is to make sure the 'crredy will be protective of public health and the environment. At
many sites, where the remedy has been constructed, EPA continues to ensure it remains protective by
squiring reviews of c.eanups every five years. I: is important for EPA to regularly check on these sites
to ensu-c the remedy is wording properly. These reviews rdertify ssues (if any) that may affect the
arotecuvencss of the conslt jcted 'ernedy and, if necessary, recommend action',s) necessary to
dddrc'iis then*.
I here are many phases of the Superfund cleanup process including cons deringfuture use and
redevelopment at sites and conducting oost cleanup .Toritoring of sites. I-PA must ensure the
remedy is protective of public health and the environment and any redevelopment will uphold the
protecdveness of the remedy into the future.
The Supedxmd program, 3 federal p'ogram established by Congress in 1980, investigates and clears
jp the most complex, uncontrolled or abandoned hazardous waste sites in the country and
endeavors to facilitate activities to retcm them to productive use. In total, mere are 135 Superfund
sites across the EPA's Pacific Southwest Region.
Learn more about Superfund and other clear up sites in the Pacific Southwest
't?pa.Kotf/s„porfurc--.
learn rrore about LPA's Pacific Southwest Region Tc-southwest-nw(fla-ceruef>, Connect
with US On Facebook r/J --bltp-s//'."."."^ Inr e:>nn*,( rin.'Vp-iit^ior^ 30C on X ,
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 109
-------
Contact Us to ask a question, provide feedback, or report a
problem.
LAST U PDATED ON FEBRUARY 9, 2024
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110 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites arid the Offsite OU
-------
Appendix E: Interview Forms
Five-Year Review Interview Record
Site:
AMD 901/902 Thompson Place Superfund Site,
TRW Microwave Superfund Site and Triple Site Offsite
Operable Unit
EPA ID No:
Interview Questionnaire
Date: Feb. 7, 2024
(Fill in the components below, one line per person if multiple persons are providing responses)
Name
Organization
Title
Telephone
Email
Jennifer
Garnett
City of
Sunnyvale
Communications
Officer
408-730-7476
jgarnett@sunnyvale.ca.gov
(Record responses to the questions below)
1) What is your overall impression of the project?
The EPA project team was genuinely committed to informing our community, in particular the impacted
residents, schools, etc. They involved the City and the school district with developing the outreach materials
and were very receptive to our comments and input. They were also good partners with media inquiries.
2) What effects have site operations had on the surrounding community?
I am not aware of any effects. The school district may have greater insight into this due to their proximity to
the location.
3) Are you aware of any community concerns regarding the site or its operation and administration? If so,
please give details.
Not at this time.
4) Are you aware of any events, incidents, or activities at the site such as vandalism, trespassing, or
emergency responses from local authorities? If so, please give details.
Not aware of anything.
5) Do you feel well informed about the site's activities and progress?
Melanie Morash, the EPA project manager, and her team did a good job keeping us informed at various
points in time through emails, in-person meetings and site visits. See #6 below for related suggestion.
6) Do you have any comments, suggestions, or recommendations regarding the site's management or
operation?
The longevity of the project makes maintaining continuity of information challenging. Many City staff
members who were involved at the project's inception are no longer employed with us. For all similar
projects, I recommend that EPA send out simple quarterly or semi-annual updates that help keep everyone
up-to-date with progress. Even if the message is "no news" that is helpful.
Additional Site-Specific Questions
[If needed]
Sixth Five-Year Review for AMD 901/902andTRW Superfund Sites and the Offsite OU
111
-------
Five-Year Review Interview Record
Site:
AMD 901/902 Thompson Place Superfund Site,
TRW Microwave Superfund Site and Triple Site Offsite Operable
Unit
EPA ID
No:
Interview Questionnaire
Date:
(Fill in the components below, one line per person if multiple persons are providing responses)
Name
Organization Title
Telephone Email
Brandt Burns
Sunnyvale SD
Director, Facilities &
Operations
408-522-
8200
brandt.burns@sesd.o
rg
(Record responses to the questions below)
1) What is your overall impression of the project?
My overall impression is that it has gone well. Communication from Locus and the documentation and
information that is presented seems thorough.
2) What effects have site operations had on the surrounding community?
Besides some questions from parents when the testing signs are posted the impact to the surrounding
community has been minimal.
3) Are you aware of any community concerns regarding the site or its operation and administration? If
so, please give details.
We do have a few parents who have expressed concerns with there not being enough signage and
notification about the site conditions. But those parents have been directed to the front office to review
the reports or have been in touch with Locus regarding follow-up information.
4) Are you aware of any events, incidents, or activities at the site such as vandalism, trespassing, or
emergency responses from local authorities? If so, please give details.
None that relate to this being part of a Superfund Site.
This is a school campus so there have been events as described in the question at various points over
the past 5 years. None of which are in relation to the site being part of the Superfund area.
5) Do you feel well informed about the site's activities and progress?
Yes, the communication has been good in regard to when testing is needed or access needs to be
granted. Obviously with this being an active school site there have been some coordination issues that
Locus has needed to work around but that is to be expected.
6) Do you have any comments, suggestions, or recommendations regarding the site's management or
operation?
None.
7) Do you have any comments, suggestions, or recommendations regarding the project?
None.
Additional Site-Specific Questions
[If needed]
112 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
Five-Year Review Interview Record
Site:
AMD 901/902 Thompson Place Superfund Site,
TRW Microwave Superfund Site and Triple Site Offsite Operable Unit
EPA ID No:
Interview Questionnaire
Date: February 26, 2024
(Fill in the components below, one line per person if multiple persons are providing responses)
Name
Organization Title
Telephone
Email
Lenny Siegel CPEO
Executive Director
650-961-8918 LSiegel@cpeo.org
(Record responses to the questions below)
1) What is your overall impression of the project?
An off-site vapor intrusion investigation in underway, with some homes needing mitigation. But though I've
expressed interest I've heard nothing about it lately.
2) What effects have site operations had on the surrounding community?
Very little. Most people are not aware of it.
3) Are you aware of any community concerns regarding the site or its operation and administration? If so,
please give details.
I am concerned that nearby residents, school staff and families, and workers and shoppers in commercial
buildings are unaware of the potential for vapor intrusion.
4) Are you aware of any events, incidents, or activities at the site such as vandalism, trespassing, or emergency
responses from local authorities? If so, please give details.
No
5) Do you feel well informed about the site's activities and progress?
No.
6) Do you have any comments, suggestions, or recommendations regarding the site's management or
operation?
Buildings with a potential for vapor intrusion should have signage linking to information about the site, even if
indoor air contamination is considered acceptable.
7) Do you have any comments, suggestions, or recommendations regarding the project?
In 2016 EPA was doing a good job of community outreach. Since the contamination has, to my knowledge, not
gone away, why isn't there a similar level of outreach today?
Additional Site-Specific Questions
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 113
-------
Five-Year Review Interview Record
Site:
The Triple Site: AMD 901/902 Thompson Place Superfund
Site, TRW Microwave Superfund Site, Triple Superfund Site
Offsite Operable Unit, and Phillips Site.
EPA ID
No:
CAN000900265
CAD009159088
CAD048634059
CAD070466479
Date: March 10 2024
Interview Questionnaire
Interviewee
Name
Method
Title
Employer
Email
Ashley
Gjovik
Self-
Reported
Worker at 825 Stewart
Drive (2017-2021)
Apple Inc
ashleymgjovik@protonmail.co
m
Responses
1) Overall impression of the project:
The Triple Site is a complex contaminated remediation site with numerous comingled plumes spanning
enough area to be considered a Superfund "mega-site." (ESS CSM, AECOM, 2020). Based on the site
documentation and reports, the site's pollution continues to migrate downgradient, whilst upgradient
pollution from other remediation sites continues to migrate northward and into the Triple Site aquifers.
Because of this complexity and continued migration "significant uncertainty remains regarding fluid flow,
plume containment, and restoration timelines." (ESS CSM, AECOM, 2020). Remediation of The Triple Site has
lagged far behind earlier expectations. (USACE, FYR, 2019).
The Triple Site primarily occupies Sunnyvale census tract 6085508704 which is in California's 43rd percentile
for unemployment and 72nd percentile for linguistic isolation. (CalEnviroScreen4.0). The population of the
tract is 7,587 people of which 47.28% are Asian American, 25.86% are White, 19.65% are Hispanic, and
3.99% are Black. (Id.). 16% of residents have low income and 21% speak limited English. (US EPA EJ Screen).
Resident's primary languages include English (45%), Spanish (22%), Chinese (11%), Tagalog (7%), and others.
80% of the population are non-White.
2) Impact of site operations on the surrounding community:
The groundwater and soil VOC contamination at the Triple Site vaporizes into the ambient, outdoor air -
either directly up from un-capped ground, or through the exhaust of vapor intrusion mitigation systems.
Today the Triple Site still contains high levels of Class A and Class B carcinogenic substances including TCE
and Vinyl Chloride. Recent medical studies have shown that living near a Superfund site like The Triple Site
can reduce life expectancy by multiple years.
US EPA documents, including the 2019 FYR, note "outdoor air TCE levels have shown a generally upward
trend over time since regular sampling commenced in January 2015." (FYR Issues and Recommendations
Report 2021). As of 2019, there was up to 3.6ng/m^ of TCE in the ambient air at The Triple Site. (FYR 2019,
page 27). More recent results do not appear to be published yet.
The worst of the air pollution rising directly from the ground is surely around the 'ground zero' mound on
the Philips site just south of Stewart Drive towards Wolfe. Notably, this area, (which contains upwards of
20,000 ng/m^ of TCE in shallow groundwater), has no fencing or barrier, nor any type of warning to the
public - instead a sidewalk winds around 'ground zero' taking pedestrians directly alongside the hazard.
3) Awareness of community concerns regarding the site and/or its operation and
administration:
There's confusion around morphology, migration, and comingling with numerous units and sub-units including:
Triple Site with TRW Microwave, Philips/Signetics, AMD, and OOU
SDOU with five sub-units including 999 Arques, Inprint/Sobrato, and CAE
SDOU1 with three sub-units including National Semiconductor and AMD/Kifer
114 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
-------
CSOU with sub-units including Mohawk and Fairchild/HP
AMD 915 Site, Former United Technologies Site, Pilkington Barnes/Hind Site, etc.
In addition to the number of sites, the sites are also overseen by a variety of government agencies (federal,
state, local) with disparate site management plans.
There's ambiguity around buildings within TRW Microwave site:
825 Stewart is generally noted as the only building for the site, however TRW Microwave also used
455 De Guine, 835 Stewart, etc.
There are no published records of vapor intrusion evaluations for 455 De Guine or 835 Stewart Drive.
US EPA documents describe attempts to contact the owner of 830 Stewart Drive with no response as of
around 2022. This building is a large office complex with probably around ~30 different businesses. My
prior therapist had an office there and I fainted in her office in 2020 (when I was also fainting at TRW
Microwave and near the exhaust of Apple's fabrication activities at a site in Santa Clara). She did not know
the site was a Superfund site, and later, I was the one to inform her. The owner of 830 Stewart Drive is
assumably not informing any of the tenants of the CERCLA status.
Many people who work, live, or shop on Triple Site do not know it is a Superfund site. There is generally no
direct communication from the agencies or Responsible Parties to those potentially impacted by the
pollution. There are few or no warnings of possible air contamination. To that point, I highly encourage the
US EPA to consider other ways to notify the community about the upcoming FYR process beyond printing
an ad in a local physical paper (it is not even online/digital), as very few people are likely to be made aware
of the site or this process otherwise.
4) Knowledge of events, incidents, or activities at the stie such as vandalism, trespassing, or
emergency responses from local authorities:
At 825 Stewart Drive (TRW Microwave Site), at least the following government inspections occurred since
the prior Five-Year Report:
2019 0129 - Sunnyvale HazMat inspection (violation of CFC 315.3.3)
2020 07 01-Sunnyvale HazMat inspection (violation of CFC 315.3.3 and CA NFPA 25Tbl 5.1.1.2)
202109 09 - Sunnyvale HazMat inspection (violation of CFC 315.3.3)
o Corrective action due 10 09 2021 but overdue and resolved 1117 2021
202108 19 - US EPA CERCLA site inspection of vapor intrusion controls
At 825 Stewart Drive (TRW Microwave Site), I witnessed the following CERCLA-related activities/issues
occurring since the prior Five-Year Report:
202105 - Operator conducted first floor survey since 2015.
202106 - Operator identified cracks in the slab. Operator refused to test indoor air prior to
fixing it and refused to notify US EPA of the cracked slab.
202107 -1 told US EPA about the cracked slab and US EPA requested a site inspection to see the
floor.
202108 - Site operator repaired floor prior to US EPA and Northrop Grumman inspection.
202109 -1 was fired in retaliation for making CERCLA disclosures. See US Department of Labor
OAU case: Ashley Gjovik vApple Inc., 2024-CER-00001.
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 115
-------
At 825 Stewart Drive (TRW Microwave Site), I witnessed the following health/safety issues:
2019-09 -1 was dizzy and almost fainted at TRW Microwave
2019 11 - Brown water in kitchen plumbing at TRW Microwave
2020 03 -1 fainted at 825 Stewart Drive and 830 Stewart Drive.
2020 08 - Workers complained about air quality issues at TRW Microwave
202104 - I filed a Worker's Compensation claim about my 2019 fainting spell, attributing
it to vapor intrusion.
202107 - Operator of TRW Microwave used ADA accommodations as a response to my vapor
intrusion concerns and offered to provide me an air purifier at my desk to mitigate the known
pollution. I complained of ADA misuse.
A search of published Sunnyvale city records between January 12020 and now, shows the following
complaints and reports across The Triple Site:
- 2024-02-16,4xx N Wolfe Road, "burglary-commercial," (SPD#240001413, 240001414)
2024-02-15, 9xx E. Arques Ave, "burglary-commercial," (SPD#240001378)
2023-11-28, 815 Stewart Drive, "broken down trailer behind Movement Sunnyvale with a rusted
propane tank, within a few feet of the building's rear wall." (NP-2023-3450).
- 2023-07-12,830Stewart Drive, "HVAC, no airflow 128-130," (NP-2023-2296)
2023-06-05,811 E. Arques Ave, "weeds at Lowes. RP mentioned to mayor." (NP-2023-2702)
2023-05-18,770 Lucerne Dr, "Homeless encampment on private property," (NP-2023-2423)
2023-03-20, 875 E. Arques Ave, "overgrown weeds and fallen trees and branches on
property," (NP- 2023-2150)
- 2023-02-22, 906 E. Arques Ave, "green graffiti," (NP-2023-2064)
2023-01-30, 785 E. Duane Ave, "construction daily without permits. Bottom two units. Dust and
noise are affecting the neighbors at 775 E Duane." (NP-2023-1981)
2023-01-27, 632 Bernal Ave, "unpermitted addition in the backyard," (NP-2023-1973)
2022-12-27, 825 Stewart Drive, "noise - parking lot sweeper," (NP-2022-1898)
2022-12-05,455 De Guine Drive, "Someone is using a leaf blower in the middle of the night
(typically around 3am always on Saturday," (NP-2022-1832)
2022-06-27, 625 Johanna Ave, "unlivable conditions. Electrical and some plumbing issues,
bathroom floor is always wet with water leakage," (20221144)
2022-05-22,611 San Luisito Way, "Hot water coming out discolored, yellow or brown," (#20220941)
2022-05-09, 830 Stewart Drive, 'The property had a load bearing wall removed over the
weekend. No permits were filed for this completed construction job." (#20220861)
2022-03-28,815 Stewart Drive, "weeds in the front property Planet Granite" (#20220610)
2022-03-22,811 E Arques Ave, "weeds in the vacant lot along Stewart Drive," (#20220611)
2021-09-21,811 E Arques Ave, "weeds in the landscaping area along Stewart Dr," (#20211836)
2021-03-29, 663 Cypress Ave, "person living in the garage and shed," (#20210885)
2021-01-24,602 Johanna Ave, "demo without permit," (#20210320)
2020-12-10, 920 De Guine Drive, "noise-landscaping company comes every weekend and
starts leaf blowing at 6am," (#20201513)
2020-12-10, 639 Johanna Ave, "construction - no permits on file, hears construction
noises, sees modifications done to the residence." (20201571)
2020-12-01, 849 GaltTr, 'Trash from community trash receptable in various places. Numerous
residents have complained, but HOA fails to take action solve problem. Meanwhile, trash and
debris around trash bins and blow all over property." (#202001552)
2020-09-27, 678 Cypress Ave, "cardboard and bottles in the front yard, garbage and debris
throughout house and backyard, rat droppings in the house and backyard." (#20201299)
2020-03-11, 910 Thompson Place, "overgrown vegetation - ivy blocking driver view on De
Guine Drive," (#20200597)
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5) Access to information about the site's activities and progress:
A) USEPA Website
The US EPA webpages for the Triple Site sites have not been updated frequently and are missing many
critical documents for the sites. I am not aware of any type of outreach to community members at the
Triple Site other than the Philips/OOU activities per the 2019 Order. CalEPA documents on Geotracker
have not been transferred and/or republished by US EPA creating a data gap on the US EPA website.
B) EPA GAMA Data
The groundwater sampling data for the Triple Site sites has not been uploaded to the GAMA Groundwater
Information System for over 5 years, resulting in a grossly inaccurate picture of groundwater quality in
the area when using the CalEPA GAMA tool.
C) Air Quality Emissions
Other than the 2019 FYR, I have not seen any public information about the known TCE air pollution in the
ambient air at the site. It also appears that TRW Microwave, AMD 901/901, and OOU have not registered
with CARB for any emissions or exhaust. Philips does appear to be registered through Lowe's but it is
unclear if it is tracking the soil/groundwater vaporization emissions or only commerce emissions. All sites
with emissions should have CARB permits and proper monitoring.
Further, there does not appear to be any ongoing air quality monitoring for the ambient air or for the
mitigation system exhaust stacks. If there are monitors, they are not accessible to the public and it does
not appear the data is being published. This data is especially critical for the many new residential
developments on Triple Site, and those which are fence line communities to VIM activities and
technology.
The Triple Site plumes are unstable and pollution continues to increase from upgradient sources, which
should drive an increase in the frequency and extent of vapor intrusion testing and VIM operations. The
TRW Microwave air testing apparently finally occurred in 2023 (nearly 8 years after the last testing) but
the results still have not been published and the US EPA response that was published complained the
testing analysis was "inaccurate," "confusing," and "fundamentally incorrect." (VI Evaluation Report, US
EPA, Aug. 2023). It is unclear if other TRW buildings have been tested, and there has not been much
communication about the current testing at Lowe's (Philips Site).
D) Real Estate
"Residences are being sold in the OOU and building permits for construction are being issued by the city
without notification of site conditions and transmittal of mitigation system O&M plans and EPA
requirements to existing owners, prospective purchasers, and new buyers. An Institutional Controls" plan
needs to be prepared to address this gap, the development of which will be coordinated with the city of
Sunnyvale to integrate into their existing permitting process and municipal record keeping system."
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(Triple Site - Site Management Plan, US EPA, 2021, page 4). This must be urgently addressed if it is not
already.
6) Comments, suggestions, or recommendations regarding the site's management and/or operations:
A) Record of Decision and Deed Updates
Most of the RODs for Triple Site are no longer operating, with the ROD for TRW no longer in operation for
over 20 years. Documentation for the site repeatedly urges the agencies to update the ROD, but so far, the
ROD has not been updated. This should be prioritized. It is unclear if Philips/Signetics is now a CERCLA site or
if it is still a RCRA clean-up site.
The RODs also do not include plans for vapor intrusion. As the RODs will need updated to consider vapor
intrusion anyway, the teams should also consider modern understandings of vapor intrusion pathways
such as conduits like sewer lines. (DTSC Supplemental Guidance Screening and Evaluating VI, 2023, page 5-
6). The Triple Site has extensive contamination of shallow groundwater which likely puts conduits like
sewer and other utility lines at a high risk for transporting vapors into buildings, but which has not been
considered in most vapor intrusion plans at the site.
The deed for TRW Microwave has been out of date for over a decade and site documentation continues
to remind the agency and parties to update the deed to comply with C.C.C. Section 1471(b). (FYR, 2019,
US ACE/US EPA). The deed update should be prioritized.
B) VIM Vent Riser Best Practices
Many buildings on Triple Site use a VIM system which utilizes some form of exhaust vents. Apple became
the tenant of TRW Microwave in 2015. Apple's installation of a new HVAC system for the building in late
2015 included Apple sawing the sub-slab exhaust vent stacks on the main building roof down from three
feet to one foot and then installing the HVAC system intakes in "close proximity" to the sub-slab vapor
exhaust vents, "without consideration for the function of the [sub-slab] system vents and their function."
(Evaluation of Passive Sub-Slab Depressurization System, AECOM, 2022). The HVAC intakes for the area of
the building where Gjovik worked were in "the assumed sphere of influence" of the vent exhaust, including
the chemicals TCE and vinyl chloride. (Id.)
Apple's tampering with the exhaust stacks and indifference towards the exhaust's proximity to HVAC
intakes resulted in a significant risk of re-entrainment of the hazardous waste vapors and gases into the
HVAC system, and thus into the indoor air of the building where Gjovik and her coworkers would be
exposed. US EPA intervened in July 2021 after discovering the issue, however Apple apparently took
multiple years to correct the issue and no corrective action report has been published. Issues like this
should trigger incident reports and an after-action review with the agency, including publication of reports
for community awareness.
California Labor Code § 5154.1(e)(4)(d) requires that these types of stacks exhaust upward from at least
seven feet above the highest portion of the roof. California Mechanical Code § 407.2.1 requires outdoor
air intakes be placed at least 25 feet away from any "exhaust outlets of ventilating systems... that may
118 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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collect.... Noxious fumes. California Labor Code § 5143(a)(1) and § 5143(c)(1) prohibit the exhaust of gas
and vapor in a way that causes harmful exposure to employees.
Also, current Bay Area RWQCB guidance for Vapor Intrusion Mitigation includes targeted guidance for
vent risers which should be incorporated into O&M plans and other site agreements. To avoid creating
issues like Apple did, any party installing/operating this type of VIM system should be aware of, and
comply with, applicable laws and also collect vent riser exhaust air as a sample when they collect indoor
and outdoor air, which enables analysis to verify there is no reentrainment. Monitoring best practices also
include monitoring discharge exhaust rates, air flow rates, and ensuring exhaust complies with permit
requirements. Parties should also ensure they obtain permits from the Air District for their CERCLA related
emissions, which needs to be done here.
C) VIMS and Slab Maintenance Best Practices
Best practices for VIMS includes incident reports and 5-Year Reports. (SFB RWQCB, VI Mitigation
Guidance, 2022, pages 53-54). In addition, occupants of a building with a VIM should be notified of the
VIM's presence, purpose, and function - and this notification should be captured in the O&M plan. (Id at
page 44).
In addition to issues with the operator at TRW Microwave refusing to notify the occupants of the building
about the VIMS, and refusing to notify the US EPA about possible issues with the VIMS, the operator also
failed to conduct regular slab inspections, and was neglectful with the interior sub-slab ports. US EPA
documents note issues with at least four of the ports, including that one was "compromised," two were
"missing," and one was not poured well/rusted. It also appears Apple took multiple years to correct the
issues.
Further, another issue with the oversight at TRW Microwave was poor record keeping about the locations
of sub-slab ports and also indoor air testing locations. In fact, there are several test result entries between
2003-2015 which use a location name/number previously associated with a completely different area of
the building. The current documentation is incoherent and creates great difficulty in analyzing trends over
time. Responsible Parties and PRPs should gather records and try to create a revised summary of historic
details with consistent location names if possible.
Indoor air monitoring plans should be based on site conditions and approved by US EPA. However, in
December 2015, the most recent published indoor air testing was performed at TRW Microwave and the
US EPA "approved" the wrong data. There was an earlier test in May 2015 prior to Apple's renovations
which reported the highest amount of TCE at 0.58ng/m^. After Apple's renovations that penetrated the
slab and compromised the exhaust vents, the December 2015 testing showed results with double the
amount of TCE in the air compared to May 2015 (0.58ng/m^, 1.2 ng/m^). US EPA's approval letter cites
the 0.58ng/m^ amount as supposedly the highest amount in December 2015, which is incorrect and
implies US EPA did not actually review the December 2015 results. This mistake was then repeated in the
2019 FYR.
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The December 2015 results showed a dramatic and sudden increase in TCE under the floor of the building.
TCE concentrations under the lobby floor increased from 250 ng/m^ in May 2015 up to 8500 ng/m^ in
December 2015 in the area of the building closest to upgradient 'Ground Zero.' TCE air concentrations
under other areas of the building remained stable, such as the air under my lockdown in the main building
presenting 1900 ng/m^ of TCE vapor in both December 2013 and December 2015 - however the indoor
air vapor intrusion doubled between May and December 2015 in the same area, implying that Apple's
renovations reduced the effectiveness of the VIMS.
In addition, the December 2015 results showed exceeding levels of Toluene and Ethylbenzene in the indoor
air, as well as the chemicals in the sub-slab air, in the groundwater, and in upgradient plumes - however the
results were ignored and assumed to be unrelated, but no testing was done to confirm the assumption.
Communication about the matter in 2021 also failed to consider the newer chemical spill in 2008 with
Toluene entering the soil and groundwater and causing significant new contamination. (Detection of
Toluene, CDM, 2008).
7) Comments, suggestions, or recommendations regarding the overall project:
A) Zoning Plan
While there has been improvement in some of the aquifers, the B1TCE contour "has remained relatively
stable for 30 years." (Annual Groundwater Report, Philips, 2022). Much more work needs to be done.
Despite the current conditions of the Triple Site, around March 2023 the city of Sunnyvale converted the
property to Residential zoning, apparently without consulting US EPA. ("Future Opportunity Sites -
Stewart and DeGuine"). This should be urgently reassessed and corrected as appropriate.
In addition to ensuring diligence with current conditions, planning must consider that the site conditions are
actively changing and worsening across multiple plumes, and per site across Triple Site.
Signetics/Philips (811 Arques) is upgradient of TRW Microwave and the contaminated groundwater
plumes are already migrating under TRW Microwave, and then into the OOU. Recent testing at 811 Arques
showed very high levels of TCE, vinyl chloride, and 1,2-DCE. (Annual Groundwater Report, Philips, 2022;
Locus Tech, 2021). TCE is present at levels up to 16000-20000 ng/m^ in shallow groundwater flowing
towards TRW Microwave. Vinyl chloride is present in shallow groundwater in levels up to 1900 ng/m^ and
1,2-DCE at levels up to 60000 ng/m^ - also migrating towards TRW Microwave. (Id.)
The 2023 groundwater monitoring report for TRW Microwave showed elevated and increasing levels of
pollution in the southern groundwater wells, apparently showing new contamination from upgradient
sites. With only a few exceptions, the highest elevations of pollution at TRW Microwave are on the
southern edge of the property near the upgradient sources, and the lowest concentrations are at the
northern edge of the property the furthest way from upgradient sources - however, some of the northern
wells have also started showing increased contamination which implies that the upgradient contamination
may have already migrated under the building and is then migrating downgradient north of the property.
The southern wells near upgradient sources show increased contamination of TCE, C-DCE, and vinyl
120 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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chloride including in the shallow A and B1 aquifers - including TCE up to 1300 |Jg/m^, vinyl chloride up to
22 |Jg/m^, and C-DCE up to 900 ng/m^. (2022 Annual Groundwater Report, AECOM/GES, June 2023).
B) Southern Contours of Signetics Site
The Triple Site shallow groundwater and aquifer exposure pathways for vapor intrusion are poorly
delineated, or completely unknown, for the Philips/Signetics plume south of Arques. For years, maps show
the contours of the plume entering the property (between Arques and Central, along Wolfe), with question
marks. Despite this, a large new development was constructed and leased without any sort of hazardous
waste assessment in the ElR or with a regulatory agency. (This gap was confirmed through PRA requests).
This property also appears to have other plumes entering its aquifers, including Mohawk and CSOU, from
the south (Central Expressway) and east (Sunnyvale Corporate Yard) boundaries. This site should also be
evaluated as part of the Philips review or assigned to the Mohawk and/or CSOU teams to evaluate.
If the tenant of this site south of Arques, (Apple), refuses to cooperate in the investigations, enforcement
action should be considered against the party due to a continued pattern of non-cooperation in agency
remediation activities in this area. I can provide a dossier of evidence upon request.
C) Mohawk Plume
The Mohawk Plume is flowing downgradient into the Triple Site aquifers. However, the Mohawk Plume
itself still may continue to worsen as there is still existing soil contamination which could then leach into
the groundwater and then that groundwater may also migrate to Triple Site. Contaminated soil was
recently identified on the western edge of the Mohawk site with 680 ng/m^ TCE, 35000 |Jg/m^ PCE, and
180 ng/m^ Benzene. The groundwater flow is directed towards the Philips Site, and then the TRW
Microwave site. (Mohawk - Five Year Status, 2023, Apex). Recent groundwater monitoring of the
Mohawk plume north of Arques, flowing to Triple Site, already showed 465 ng/m^ of TCE and 314 ng/m^
of 1,2-DCE. (Id.). Along Mohawk and CSOU plumes, there are also at least two active USTs registered with
the Sunnyvale Department of Public Safety, and which are upgradient from Triple Site. (Geotracker).
Additional Responses about Triple Site
8) Climate Change & Groundwater Rise
The updated ROD for the Triple Site sites should also include considerations for imminent groundwater rise
due to sea-level rise caused by climate change. Much of the contaminated groundwater at Triple Site is
already near to the surface, but with groundwater rise the pollution could potentially raise and pool at the
surface, creating a new type of hazard. At the very least, increased risk and severity of vapor intrusion
should be anticipated. Similarly, there should be consideration of an increase in extreme weather events
including floods, wind storms, fires and smoke, snow and freezing rain, heat waves, and other events
impacting the site controls and contamination.
9) Health Considerations
A)TCE & TSCA
Since the last Five-Year Report in 2019, toxicological research and guidance for vapor intrusion evaluations
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 121
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have continued to advance. As of January 2023, the US EPA issued a Final Risk Evaluation for
Trichloroethylene under TSCA. US EPA found TCE creates an unreasonable risk to public health as a whole
chemical. In October 2023, US EPA proposed "to ban the manufacture, processing, and distribution in
commerce of TCE for all uses." The US EPA also proposed an ECEL of either 0.0011 ppm or 0.0040 ppm over
an 8-hour day, replacing the OSHA standards for TCE. (Trichloroethylene, Regulation Under the Toxic
Substances Control Act, 40 CFR Part 751, 2023).
Triple Site RODs and land use covenants should consider the new TSCA standards for TCE exposure. The
prior OSHA PEL for TCE was lOOppm, Cal/OSHA PEL was 25ppm, and the US EPA Commercial level was 3.0
Hg/m^. Under a new protective level of 0.00589 mg/m^ - 0.02143 mg/m^, all published vapor intrusion
testing results at TRW Microwave documented air pollution with levels of TCE that create an unreasonable
risk to human health under TSCA. Similarly, the most recent published sub-slab vapor results (such as 1900
Hg/m^ and 8500 ng/m^), using the 2023 DTSC sub-slab gas attenuation factor of 0.03, produce results (57-
255 ng/m^) which would also exceed all existing and new health thresholds (DTSC, VI, 2023, page 8; TSCA).
An aggressive vapor intrusion mitigation plan is needed.
B) Prop 65 / Right to Know
The ROD/deed should consider the potential applicability of Proposition 65 disclosures and warnings for
community members exposed to carcinogenic vapor intrusion and ambient air vapors. SARA and Right to
Know should also be considered for exhaust and ambient air pollution.
Further, due to the extent of the pollution, and imminent worsening of conditions at Triple Site - a new
health study should be considered. The last public health baseline was in 1990 and there have been
dramatic advancements in science and medicine since then, as well as advancements in understanding of
the conditions at the Site. The extensive pollution of carcinogenic chemicals creates a risk for cancer clusters
around the worst areas at the site.
122 Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU
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including:
Triple Site with TRW Microwave, Phifips/Signetics, AMD, and OOU
SDOU with five sub-units including 999 Arques, Inprint/Sobrato, arid CAE
SDOU1 with three sub-units including National Semiconductor and AMD/Kifer
CSOU with sub-units including Mohawk and Fairchiid/HP
AMD 915 Site, Former United Technologies Site, Pilkington Barnes/Hind Site, etc.
In addition to the number of sites, the sites are also overseen by a variety of government agencies (federal,
state, local) with disparate site management plans.
There's ambiguity around buildings within TRW Microwave site:
- 825 Stewart is generally noted as the only building for the site, however TRW Microwave also used; 455
De Guine, 835 Stewart, etc.
There are no published records of vapor intrusion evaluations for 455 De Guine or 835 Stewart Drive.
US EPA documents describe attempts to contact the owner of 830 Stewart Drive with no response as of
around 2022. This building is a large office complex with probably around -30 different businesses. My prior
therapist had an office there and I fainted in her office in 2020 {when I was also fainting at TRW Microwave
and near the exhaust of Apple's fabrication activities at a site in Santa Clara). She did not know the site was
a Superfund site, and later, 1 was the one to inform her. The owner of 830 Stewart Drive is assumably not
informing any of the tenants of the CERCLA status
Many people who work, live, or shop on Triple Site do not know it is a Superfine! site. There is generally no
direct communication from the agencies or Responsible Parties to those potentially impacted by the
pollution. There are few or no warnings of possible air contamination. To that point, I highly encourage the
US EPA to consider other ways to notify the community about the upcoming FYR process beyond printing
an ad In a local physical paper {it is not even online/digital), as very few people are likely to be made aware
of the site or this process otherwise.
4) Knowledge of any events, incidents, or activities at the site such as vandalism,
trespassing, or emergency responses from local authorities:
At 825 Stewart Drive (TRW Microwave Site), at least the following government inspections occurred since the
prior Five-Year Report;
- 2019 01 29 - Sunnyvale HazMat inspection (violation of CFC 315,3.3)
- 2020 07 01 - Sunnyvale HazMat inspection (violation of CFC 315.3.3 and CA NFPA 25 TO 5.1.1.2)
2021 09 09 - Sunnyvale HazMat inspection (violation of CFC 315.3.3)
o Corrective action due 10 09 2021 but overdue and resolved 11 1? 2021
2021 08 19 - US EPA CERCLA site Inspection of vapor intrusion controls
At 825 Stewart Drive (TRW Microwave Site), I witnessed the following CERCLA-related activities/Issues
occurring since the prior Five-Year Report:
2021 05 - Operator conducted first floor survey since 2015
- 2021 06 - Operator identified cracks in the slab. Operator refused to test indoor air prior to fixing it and
refused to notify US EPA of the cracked slab.
2021 07 -1 told US EPA about the cracked slab and US EPA requested a site inspection to see the floor.
2021 08 - Site operator repaired floor prior to US EPA and Northrop Grumman inspection.
- 2021 09 -1 was fired in retaliation for making CERCLA disclosures. See US Department of Labor OALJ
case: Ashley Gjovik v Apple Inc., 2024-CER-00001.
At 825 Stewart Drive (TRW Microwave Site), I witnessed the following health/safety issues:
- 2019-09 -1 was dizzy and almost fainted at TRW Microwave
2019 11 - Brown water in kitchen plumbing at TRW Microwave
202C 03 -1 fainted at 825 Stewart Drive and 830 Stewart Drive.
2020 08 - Workers complained about air quality issues at TRW Microwave
Five-Year Review: The Triple Site | Interview: Ashley Gjovik (Worker} I Page: 2 of 8
Sixth Five-Year Review for AMD 901/902 and TRW Superfund Sites and the Offsite OU 123
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2021 04 -1 lied a Worker's Compensation claim about my 2019 fainting spell, attributing it to vapor
intrusion.
- 2021 07 - Operator of TRW Microwave used ADA accommodations as a response to my vapor intrusion
concerns and offered to provide me an air purifier at my desk to mitigate the known pollution, I
complained of ADA misuse,
A search of published Sunnyvale city records between January 1 2020 and now, shows the following
complaints and reports across The Triple Site:
- 2024-02-16, 4xx N Wolfe Road, "burglary - commercial," (SPD #240001413,240001414)
- 2024-02-15, 9xx E. Arques Ave. "burglary - commercial," (SPD #240001378)
2023-11-28, 815 Stewart Drive, "broken down trailer behind Movement Sunnyvale with a rusted propane
tank, within a few feet of the building's rear wall," (NP-2023-3450).
- 2023-07-12, 830 Stewart Drive, "HVAC, no air flow 12:8-130," (NP-2023-2296)
- 2023-06-05, 811 E. Arques Ave, "weeds at Lowes. RP mentioned to mayor,* (NP-2023-27Q2)
2023-05-18, 770 Lucerne Dr. "Homeless encampment on private property," (NP-2023-2423)
- 2023-03-20, 875 E, Arques Ave "overgrown weeds and fallen trees and branches on property,* (NP-
2023-2150)
- 2023-02-22, 906 E. Arques Ave, "green graffiti,' (NP-2023-2064)
2023-01-30, 785 E, Puane Ave, "construction daily without permits. Bottom two omits. Dust and noise are
affecting the neighbors at 775 E Duane." (NP-2023-1981)
- 2023-01-27, 632 Bernal Ave, "unpermitted addition in the backyard," (NP-2023-1973)
- 2022-12-27, 825 Stewart Drive, "noise - parking lot sweeper," (NP-2022-1898)
- 2022-12-05, 455 De Guine Drive, "Someone Is using a leaf blower in the middle of the night (typically
around 3am always on Saturday," (NP-2022-1832)
2022-06-27, 625 Johanna Ave, "unlivable conditions. Electrical and some plumbing issues, bathroom
floor is always wet with water leakage," (20221144)
2022-05-22, 611 San tuisito Way, "Hot water coming out discolored, yellow or brown," (#20220941)
- 2022-05-09, 830 Stewart Drive, "The property had a load bearing wall removed over the weekend. No
permits were filed for this completed construction job." (#20220881)
2022-03-28, 815 Stewart Drive, "weeds in the front property Planet Granite" (#20220610)
- 2022-03-22, 811 E Arques Ave, "weeds in the vacant lot along Stewart Drive,1" (#20220611)
- 2021-0S-21, 811 E Arques Ave, "weeds in the landscaping area along Stewart Dr," (#20211836)
- 2021-03-29, 663 Cypress Ave, "person living in the garage and shed,* (#20210885)
- 2021-01-24, 602 Johanna Ave. "demo without permit," (#20210320)
- 2020-12-10, 920 De Guine Drive, "noise-landscaping company comes every weekend and starts leaf
blowing at Sam," (#20201513)
- 2020-12-10, 639 Johanna Ave, "construction - no permits on file, hears construction noises, sees
modifications done to the residence," (20201571)
2020-12-01, 849 Gait Tr, Trash from community trash receptable In various places. Numerous residents
have complained, but HOA fails to take action solve problem. Meanwhile, trash and debris around trash
bins and blow all over property." (#202001552)
- 2020-09-27, 878 Cypress Ave, "cardboard and bottles in the front yard, garbage and debris throughout
house and backyard, rat droppings in the house and backyard." (#20201299)
- 2020-03-11, 810 Thompson Place, "overgrown vegetation - ivy blocking driver view on De Guine Drive,"
(#20200597)
5) Access to information about the site's activities and progress;
A) US EPA Website
The US EPA web pages for the Triple Site sites have not been updated frequently and are missing many
critical documents for the sites. I am not aware of any type of outreach to community members at the Triple
Site other than the Philips/OCU activities per the 2019 Order. CalEPA documents on Geotracker have not
been transferred and/or republished by US EPA creating a data gap on the US EPA website.
Five-Year Review: 'Hie Triple Site 1 lirt*rvi«w: Ashley Gjovik (Worker) | Page: 3 of 8
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B) CalEPA GAMA Data
The groundwater sampling data for the Triple Site sites has not been uploaded to the GAMA Groundwater
Information System for over 5 years, resulting in a grossly inaccurate picture of groundwater quality in the
area when using the CalEPA GAMA tool,
C) Air Quality & Emissions
Other than the 2019 FYR, I have not seen any public information about the known ICE air pollution in the
ambient air at the site, It also appears that TRW Microwave, AMD 901/901, and OOU have not registered
with CARB for any emissions or exhaust. Philips does appear to be registered through Lowe's but if is
unclear if it is tracking the soii/groundwater vaporization emissions or only commerce emissions. All sites
with emissions should have CARB permits and proper monitoring.
Further, there does not appear to be any ongoing air quality monitoring for the ambient air or for the
mitigation system exhaust stacks, if there are monitors, they are not accessible to the public and it does not
appear the data is being published. This data is especially critical for the many new residential
developments on Triple Site, and those which are fence line communities to VIM activities and technology,
The Triple Site plumes are unstable and pollution continues to increase from upgradient sources, which
should drive an increase in the frequency and extent of vapor intrusion testing and VIM operations. The
TRW Microwave air testing apparently finally occurred In 2023 (nearly 8 years after the last testing) but the
results still have not been published and the US EPA response that was published complained the testing
analysis was "inaccurate,'' "confusing," and "furxtamentalty incorrect." (VI Evaluation Report, US EPA, Aug.
2023), It is unclear if other TRW buildings have been tested, and there has not been much communication
about the current testing at Lowe's (Philips Site),
D) Real Estate
"Residences are being sold in the OOU and building permits for construction are being issued by the city
without notification of site conditions arid transmittal of mitigation system O&M plans and EPA requirements
to existing owners, prospective purchasers, and new buyers. An Institutional Controls'* plan needs to be
prepared to address this gap, the development of which will be coordinated with the city of Sunnyvale to
integrate into their existing permitting process and municipal record keeping system." {Triple Site - Site
Management Plan, US EPA, 2021, page 4). This must be urgently addressed if it is not already.
i) Comments, suggestions, or recommendations regarding the site's management
and/or operations:
A) Record of Decision and Deed Updates
Most of the RODs for Triple Site are no longer operating, with the ROD for TRW no longer in operation for
over 20 years. Documentation for the site repeatedly urges the agencies to update the ROD, but so far, the
ROD has not been updated. This should be prioritized. It is unclear if Phlps/Signetics is now a CERCLA site
or if it is still a RCRA clean-up site.
The RODs also do not include plans for vapor intrusion. As the RODs will need updated to consider vapor
intrusion anyway, the teams should also consider modern understandings of vapor intrusion pathways such
as conduits like sewer lines, (DTSC Supplemental Guidance Screening and Evaluating VI, 2023, page 5-8).
The Triple Site has extensive contamination of shallow groundwater which likely puts conduits like sewer
and other utility lines at a high risk for transporting vapors into buildings, but which has not been considered
in most vapor intrusion plans at the site.
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The deed for TRW Microwave has been out of date for over a decade and site documentation continues to
remind the agency and parlies to update the deed to comply with C.C.C, Section 1471(b). (FYR. 2019, US
ACE/US EPA}, The deed update should be prioritized,
B) VIM Vent Riser Best Practices
Many buildings on Triple Site use a VIM system which utilizes some form of exhaust vents. Apple became
the tenant of TRW Microwave in 2015. Apple's installation of a new HVAC system for the building in late
2015 included Apple sawing the sub-stab exhaust vent stacks on the main building roof down from three feet
to one foot and then installing the HVAC system intakes in "dose proximity" to the sub-slab vapor exhaust
vents,"without consideration for the function of the [sub-slab] system vents and their function" (Evaluation
of Passive Sub-Slab Depressurization System, AECOM, 2022). The HVAC intakes for the area of the
building where Gjovik worked were in "the assumed sphem of Influence* of the vent exhaust, including the
chemicals TCE and vinyl chloride. (Id.)
Apple's tampering with the exhaust stacks and indifference towards the exhaust's proximity to HVAC intakes
resulted in a significant risk of re-entralnment of the hazardous waste vapors and gases into the HVAC
system, and thus into the indoor air of the building where Gjovik and her coworkers would be exposed. US
EPA intervened in July 2021 after discovering the issue, however Apple apparently took multiple years to
correct the issue and no corrective action report has been published. Issues like this should trigger incident
reports and an after-action review with the agency, including publication of reports for community
awareness.
California Labor Code § 5154,1(e)(4)(d) requires that these types of stacks exhaust upward from at least
seven feet above the highest portion of the roof. California Mechanical Code § 407.2,1 requires outdoor air
intakes be placed at least 25 feet away from any 'exhaust outlets of ventilating systems... that may collect
.... Noxious fumes. California Labor Code § 5143(a)(1) and § 5143(c)(1) prohibit the exhaust of gas and
vapor in a way that causes harmful exposure to employees.
Also, current Bay Area RWQCB guidance for Vapor intrusion Mitigation includes targeted guidance for vent
risers which should be incorporated into O&M plans and other site agreements. To avoid creating issues like
Apple did, any party installing/operating this type of VIM system should be aware of, and comply with,
applicable laws and also collect vent riser exhaust air as a sample when they collect indoor and outdoor air,
which enables analysis to verify there is no reentrainment. Monitoring best practices also include monitoring
discharge exhaust rates, air flow rates, and ensuring exhaust complies with permit requirements. Parties
should also ensure they obtain permits from the Air District for their CERCLA related emissions, which
needs to be done here
C) VIMS and Slab Maintenance Best Practices
Best practices for VIMS includes incident reports and 5-Year Reports. (SFB RWQCB, VI Mitigation
Guidance, 2:022, pages 53-54), in addition, occupants of a building with a VIM should be notified of the
VIM's presence, purpose, and function - and this notification should be captured in the O&M plan. (Id at
page 44).
In addition to issues with the operator at TRW Microwave refusing to notify the occupants of the building
about the VIMS, and refusing to notify the US EPA about possible issues with the VIMS, the operator also
failed to conduct regular slab inspections, and was neglectful with the interior sub-slab ports. US EPA
documents note issues with at least four of the ports, including that one was "compromised," two were
"missing," and one was not poured well/rusted. It also appears Apple took multiple years to correct the
issues.
Further, another issue with the oversight at TRW Microwave was poor record keeping about the locations of
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sub-siab ports and also indoor air testing locations. In fact, there are several test result entries between
2003-2015 which use a location name/number previously associated with a completely different area of the
building. The current documentation is incoherent and creates great difficulty in analyzing trends over time.
Responsible Parties and PRPs should gather records and try to create a revised summary of historic details
with consistent location names if possible.
indoor air monitoring plans should be based on site conditions and approved by US EPA. However, in
December 2015. the most recent published indoor air testing was performed at TRW Microwave and the US
EPA "approved" the wrong data. There was an earlier test in May 2015 prior to Apple's renovations which
reported the highest amount: of TCE at 0.58pg/m3. After Apple's renovations that penetrated the slab and
compromised the exhaust vents, the December 2015 testing showed results with double the amount of TCE
in the air compared to May 2015 {0,58pg/m3,12 pglm3). US EPA's approval letter cites the Q.5Bfjg/m3
amount as supposedly the highest amount in December 2015, which is incorrect and implies US EPA did
not actually review the December 2015 results. This mistake was then repeated in the 2019 FYR.
The December 2015 results showed a dramatic and sudden increase in TCE under the floor of the building,
TCE concentrations under the lobby floor increased from 250 pg/m3 in May 2015 up to 8500 pg/m3 in
December 2015 in the area of the building closest to upgradient 'Ground Zero. TCE air concentrations
under other areas of the building remained stable, such as the air under my lockdown in the main building
presenting 1900 pg/m3 of TCE vapor in both December 2013 and December 2015 - however the indoor air
vapor intrusion doubled between May and December 2015 in the same area, implying that Apple's
renovations reduced the effectiveness of the VIMS.
In addition, the December 2015 results showed exceeding levels of Toluene and Ethyl benzene in the indoor
air, as well as the chemicals in the sub-slab air, in the groundwater, and in upgradient plumes - however the
results were ignored and assumed to be unrelated, but no testing was done to confirm the assumption.
Communication about the matter in 2021 also failed to consider the newer chemical spill in 2008 with
Toluene entering the soil and groundwater and causing significant new contamination. (Detection of
Toluene, CDM, 2008).
7) Comments, suggestions, or recommendations regarding the overall project:
A) Zoning Plan
While there has been improvement in some of the aquifers, the B1 TCE contour "has remained relatively
stable for 30 years" (Annual Groundwater Report, Philips, 2022). Much more work needs to be done.
Despite the current conditions of the Triple Site, around March 2023 the city of Sunnyvale converted the
property to Residential zoning, apparently without consulting US EPA. ("Future Opportunity Sites - Stewart
and DeGuine"). This should be urgently reassessed and corrected as appropriate.
In addition to ensuring diligence with current conditions, planning must consider that the site conditions are
actively changing and worsening across multiple plumes, and per site across Triple Site.
SigneticsPhilps (811 Argues) is upgradient of TRW Microwave and the contaminated groundwater plumes
are already migrating under TRW Microwave, and then into the QOU, Recent testing at 811 Argues showed
very high levels of TCE, vinyl chloride, and 1,2-DCE. (Annual Groundwater Report, Philips, 2022; Locus
Tech, 2021). TCE is present at levels up to 16000-20000 pg/m3 In shallow groundwater flowing towards
TRW Microwave, Vinyl chloride is present in shallow groundwater in levels up to 1900 pg/m3 and 1,2-DCE at
levels up to 80000 pg/m3 - also migrating towards TRW Microwave, (Id.)
The 2023 groundwater monitoring report for TRW Microwave showed elevated and increasing levels of
pollution in the southern groundwater wells, apparently showing new contamination from upgradient sites.
With only a few exceptions, the highest elevations of pollution at TRW Microwave are on the southern edge
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of the property near the upgradient sources, and the lowest concentrations are at the northern edge of the
property the furthest way from upgradient sources - however, some of the northern wells have also started
showing increased contamination which implies that the upgradient contamination may have already
migrated under the building and is then migrating downgradient north of the property. The southern wells
near upgradient sources show increased contamination of TCE, C-DCE, and vinyt chloride including in the
shallow A and B1 aquifers - including TCE up to 1300 pg/m3, vinyl chloride up to 22 pg/m3, and C-DCE up to
900 pg/m3, (2022 Annual Groundwater Report, AECOM/GES, June 2023),
B) Southern Contours of Signetics Site
The Triple Site shallow groundwater and aquifer exposure pathways for vapor intrusion are poorly
delineated, or completely unknown, for the Phiiips/Signetics plume south of Argues. For years, maps show
the contours of the plume entering the property (between Arques and Central, along Wolfe), with question
marks, Despite this, a large new development was constructed and leased without any sort of hazardous
waste assessment in the EIR or with a regulatory agency, (This gap was confirmed through PRA requests).
This property also appears to have other plumes entering its aquifers, including Mohawk and CSOU, from
the south (Central Expressway) and east (Sunnyvale Corporate Yard) boundaries. This site should also be
evaluated as part of the Philips review or assigned to the Mohawk and/or CSOU teams to evaluate.
if the tenant of this site south of Arques, (Apple), refuses to cooperate in the investigations, enforcement
action should be considered against the party due to a continued pattern of non-cooperation in agency
remediation activities in this area. I can provide a dossier of evidence upon request,
C) Mohawk Plume
The Mohawk Plume is flowing downgradient into the Triple Site aquifers. However, the Mohawk Plume itself
still may continue to worsen as there is still existing soil contamination which could then leach into the
groundwater and then that groundwater may also migrate to Triple Site. Contaminated soil was recently
identified on the western edge of the Mohawk site with 680 pg/m3 TCE, 35000 pg/m3 PCE, and 180 pg/m3
Benzene, The groundwater flow is directed towards the Philips Site, and then the TRW Microwave site.
(Mohawk - Five Year Status, 2023, Apex). Recent groundwater monitoring of the Mohawk plume north of
Arques, flowing to Triple Site, already showed 485 pg/m3 of TCE and 314 pg/m3 of 1,2-DCE. (Id,), Along
Mohawk and CSOU plumes, there are also at least two active USTs registered with the Sunnyvale
Additional Responses about Triple Site
8) Climate Change & Groundwater Rise
The updated ROD for the Triple Site sites should also include considerations for imminent groundwater rise
due to sea-level rise caused by climate change. Much of the contaminated groundwater at Triple Site is
already near to the surface, but with groundwater rise the pollution could potentially raise and pool at the
surface, creating a new type of hazard. At the very least, increased risk and severity of vapor intrusion
should be anticipated, Similarly, there should be consideration of an increase in extreme weather events
including floods, wind storms, fires and smoke, snow and freezing rain, heat waves, and other events
impacting the site controls and contamination.
9) Health Considerations
A) TCE&TSCA
Since the last Five-Year Report in 2019, toxicological research and guidance for vapor intrusion evaluations
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have continued to advance, As of January 2023, the US EPA Issued a Final Risk Evaluation for
Trichloroethvlene under TSCA. US EPA found TCE creates an unreasonable risk to public health as a whole
chemical. In October 2023, US EPA proposed "to ban the manufacture, processing, and distribution in
commerce of TCE for all uses." The US EPA also proposed an ECEL of either 0.0011 ppm or 0.0040 ppm
over an 8-hour day, replacing the OSHA standards for TCE, (Trichloroethylene, Regulation Under the Toxic
Substances Control Act, 40 CFR Part 751, 2023).
Triple Site RODs and land use covenants should consider the new TSCA standards for TCE exposure. The
prior OSHA PEL for TCE was 10Qppm, CaL'OSHA PEL was 2Sppm, and the US EPA Commercial level was
3.0 pg/m3.. Under a new protective level of 0.00589 rng/mJ - 0.02143 mg/m3, all published vapor intrusion
testing results at TRW Microwave documented air pollution with levels of TCE that create an unreasonable
risk to human health under TSCA. Similarly, the most recent published sub-slab vapor results (such as 1900
pg/m1 and 8500 pg/m3), using the 2023 DTSC sub-slab gas attenuation factor of 0.03, produce results (57-
255 mtm3} which would also exceed all existing and new health thresholds (DTSC, VI, 2023, page 8;
TSCA}. An aggressive vapor intrusion mitigation plan is needed.
B) Prop 65 I Right to Know
The ROD/deed should consider the potential applicability of Proposition 85 disclosures and warnings for
community members exposed to carcinogenic vapor intrusion and ambient air vapors. SARA and Right to
Know should also be considered for exhaust and ambient air pollution.
Further, due to the extent of the pollution, and imminent worsening of conditions at Triple Site - a new health
study should be considered. The last public health baseline was in 1990 and there have been dramatic
advancements in science and medicine since then, as well as advancements in understanding of the
conditions at the Site. The extensive pollution of carcinogenic chemicals creates a risk for cancer clusters
around the worst areas at the site.
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Appendix F: Site Inspection Report and Photos
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Site Inspection Report and Photos
Report Date: March IS. 2024
Advanced Micro Deuces TRW Microwave < Tuple Site) Superfuud Site. Santa Clara County,
California
a. Date of Visit: March 5. 2024
b Location: San Jose, CA
c. Purpose: A site visit was conducted to visually inspect and document the conditions of the
remedy, the site, and the surrounding area for inclusion into the Five-Year Review Report.
d Inspector. Matthew Wetter US Army Corps of Engineers, Env. Engineer 916-387-5019
Cody Davis US Amy Coups of Engineers, Student Eng. 208-891-3197
e. Participants:
Lilian Abreu
Joshua Mandi
Akash Caveney
Michael Zlotoff
J Wesley Hawthorne
Africa Espina
US EPA (Regulatory Oversight)
Northrop Grumman
Haley & Aldrich
Haley & Aldrich
Locus Tech
Locus Tech
A site visit to the Advanced Micro Devices (AMD)/TRW Microwave former microchip
manufacturing facilities was conducted on March 5. 2024. The inspection included visual observation
of overall site conditions and inspection of various components of the reined}" including groundwater
treatment system (GWTS) (plant and well network)., and several extraction, injection and monitoring
wells. The participants received an overview of the sites and a brief remedial history generally provided
bv Northrup, Haley Aldrich and Locus Tech staff.
On March 5. 2023. Mr. Wetter and Mr. Dams arrived at the Triple Site Superfund Site and met up with all
participants
The weather was overcast, with a slight breeze, and approximately 60 degrees Fahrenheit.
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AMD 901/902 Thompson Place Site:
The inspection team arrived at 10:05 at the former AMD 901 and 902 buildings.. The farmer AMD facility
has been Turned to a Public Storage facility. Introductions and safety brief were completed with
representatives of Haley & Aldrich. EPA. Locus Technologies, Northrop Grumman, and the US Army
Corps of Engineers. After the safety brief the group inspected the old injection compound on the north
side of the building.
The following wells were inspected; ISB1AR, ISB1 BR. ISB2AR. and ISB3BR. The .injection wells are
situated upgradient and are just west of 901 Thompson at DW-1. Ail injection wells were in a reasonably
secured location surrounded by chain link fence and a locked gate. Hie well covemigs were secured with
metal lids and a padlocks; they showed no signs of being tampered with Haley & Aldnch representatives
noted:
• Wells are monitored semi-annually.
• Last injection was in 2020 as part of a pilot programs
Next the dormant pump and teat groundwater system was inspected. Tins system was part of the original
remedy per the ROD, but lias not been operational since 2002. Hie tank lias not been used since 2020: the
tanks and piping showed signs of being sun faded but were still intact It is not clear if they could be
made operational again should the need arise, however such, assessment was beyond tlie scope of this
inspection..
The dormant recirculation system and leftover chemicals necessary to facilitate injections (Sand
remover) are in a portable secondary containment basin and are secured with ten-foot-tall chain link fence
and cinder Mock walls.
After inspecting the recirculation system the following monitoring wells were observed;
• 22DD: Monitoring well manhole was in good shape however the cap did not sit flush and had
minor amounts of standing water m the casing.
• DW-7: Monitoring well manhole was in good shape. The plug was tight and secured with a lock.
Mr. Wetter asked Haley & Aldrich representative about evidence of transient occupancy. They indicated a
generator had been stolen once, but in general no damage to wells and infrastructure, some lifter but the
adjacent commercial storage unit buildings have cameras and roving security that would prevent long
term use/living. They also indicated that they are not aware of anyone living m storage units.
See pictures 1 through 9 for associated photographs.
Sisnetics Site:
The building on this property lias recently been rebranded to Movement Clnnbmg Yoga, and Fitness but
was previously used as a climbing gym.
Dan Dueasse, engineering technician from Locus Technologies, provided a short safety brief and site
overview. 'Hie inspection team then observed the extraction and treatment system located within, a secure
fenced area of the parking lot. The system was m operation during the inspection and all systems seeiaed
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well maintained and in working order. All visible piping appeared structurally sound, and evidence of
leaks was not observed. Chemicals appeared to be stored in a safe manner. A walk around of lie security
fencing showed no signs of damage or tampering.
Mi*. Duesse mention that the adjacent building to the southwest (Plug and Play) has sump pumps for their
basements and these pumps extract groundwater before it is treated.
The following monitoring and extraction wells were observed:
• EW-S154-B1: Extraction well christy box was in good shape and steel cover was not bent.
C ompared to S154-B2, this well was much dirtier and looked generally older.
• EW-S154-B2: Extraction well christy box was in good shape and the steel cover was not bent.
• MW-S004B1: Monitoring well manhole was in good shape, plug was locked but slightly loose.
• MW-S004A: Monitoring well manhole was in good shape, label was very tight and almost
unreadable, plug was locked and tight.
• MW- S007A: Monitoring well manhole was in good .shape, A small amount of sediment was
present m the casing. Plug was locked but loose. The bolts securing the lid to casing were barely
threaded.
Locus Technologies representatives noted that the property owners where MW- S007A and MW-T8A
were difficult to work with and had previously paved over other monitoring wells
See pictures 10 through 18 for associated photographs.
TRW Site:
The TRW site is located at what is now an Apple technology center. Tlie following monitoring wells were
observed:
• MW-T8A: Monitoring well manhole was ui good shape. There was hole m the side of the pipe for
monitoring equipment that had been covered however, there were two notches cut into the top of
the well casing that would prevent it from being watertight. Hie plug was locked.
• MW-T14A: Monitoring well manhole was in good shape. It is a 1-inch well that most likely had a
piezometer present. The plug; was loose but locked
See pictures 19 through 21 for associated photographs.
Offsite Oner able Unit:
The site is mix of three schools and 300 residences. Wells adjacent to The King's Academy, a preparatory
school we inspected.
• COM-6A: Tins is an extraction wel that is in good repair but was not locked upon arrival.
• COM6-B1H: Monitoring well manhole was m good shape The well was capped and is no longer
part of the monitoring program.
• COM32-B1: This well is in a concrete christy box and not a steel monitoring well manhole. It is a
six-inch monitoring well. The screw cap was loose but locked.
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See pictures 22 though 24 for associated photographs.
AMD 915 Site:
Though this site is not par! of the "Tuple Site" the inspection team observed the onsite liquid phase
granular activated carbon (LGAC) treatment facility. The system consisted of two sets of three LGAC
canisters piped m series. The system was in operation dining the inspection and aU systems appeared to
be well maintained and in good working order Most piping and markings were faded due to exposure to
the elements however, fitting, tanks, and valves appeared to be free of leaks and in good working order.
C hemicals stored on site appeared to be appropriately labeled and stored, however it was not within the
scope of tins inspection to do an exhaustive compliance check or similar-.
Hie treatment plant is siinmmded on three sides by einderUock walls and has a steel gate seeming the
facility. There were no sips of attempted forced entry into the facility. Owe monitoring well was
observed at this site:
• 2-SR: Monitoring well manhole was in good shape. It is a two-inch monitoring well, (he plug was
slightly loose, and not locked.
See pictures 25 through 31 for associated photographs.
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Former injection system that has been dormant since 2002
Injection wells ISB2AR and ISB3BR.
PUoio
No.
3,
Photograph and Description
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IX 3 ' r^espoiti K 61033 ft
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Monitoring Well 22DD, note minor amount of water in casing-
Plioto
No.
7.
Photograph and Description
Scnid Remover warning label.
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Photo Photograph and Description
No.
Oxidizer tank for the pump and treat system.
Trojan UV Pliox oxidation system.
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Photo
No.
Photograph and Description
13.
Air stripper for pump and treat system at the Signeties site.
t ¦' * ""i
Sampling port located between equalization tank and air stripper (representative of combined
influent concentrations), facing north
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Photo
No.
23
Photograph and Description
Offsite Operable site monitoring well 6B1H.
Offsite Operable site monitoring well 32B1
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Plioto Photograph and Description
No.
Full view of the LGAC treatment system for the AMD 915 site.
One of the LGAC tanks for the AMD 915 site.
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Photo Photograph and Description
No.
250mL sample bottles stored onsite for the AMD 915 site.
Water sotrage tank for the AMD 915 treatment system.
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Photo Photograph and Description
No.
Gate for the AMD 915 LGAC treatment plant,
30."
Monitoring 2-SR well for the AMD 915 site.
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