United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R09-91/075
March 1991
&EPA Superfund
Record of Decision:
Spectra-Physics (Teledyne
Semiconductor), CA
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50Z72-101
REPORT DOCUMENTATION i. REPORT N
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EPA/ROD/R09-91/075
Spectra-Physics (Teledyne Semiconductor), CA
First Remedial Action - Final
Abstract (Continued)
chemicals are currently stored above ground. From 1982 to 1984, State investigations
identified the release of VOCs from solvent tanks into onsite soil at both areas.
Spectra-Physics and Teledyne have together and separately implemented interim actions
onsite. In 1987, Spectra-Physics excavated and removed all but one of the sumps and 6
feet of contaminated soil from the facility area, and installed a soil vapor extraction
system as an interim removal action to reduce VOCs in soil. Teledyne excavated and
removed Tank A and the surrounding contaminated soil, and installed ground water
extraction systems on and around the site to remove VOCs present in concentrations above
specified levels followed by discharge of the extracted water to the sanitary sewer
system. This Record of Decision (ROD) addresses contamination of the ground water
aquifers and onsite soil. The primary contaminants of concern affecting the soil and
ground water are VOCs including PCE, TCE, and toluene.
The selected remedial action for this site includes expanding the existing soil vapor
extraction system at the Spectra-Physics area including treatment of off-gases using
granular activated carbon; ground water pumping and treatment at both the Teledyne and
Spectra-Physics areas using air stripping followed by vapor phase carbon to control air
emissions, if the air levels exceed permitted standards, followed by discharging the
treated water into an onsite storm drain; continuing operation of the existing ground
water extraction systems at the offsite Mountain View Area, with a contingency for adding
additional air stripping capacity prior to discharge into the city sewer system; and soil
and ground water monitoring. The estimated present worth cost for the Spectra-Physics
area is $2,729,595, which includes an annual O&M cost of $188,600. The estimated present
worth cost for the Teledyne area is $2,000,000, which includes an annual O&M cost of
$86,000 for 30 years. The estimated present worth cost for monitoring the offsite
Mountain View Area is $10,496,757, which includes an annual O&M cost of $720,739 for 30
years. The estimated total present work cost for this remedial action is $18,226,352,
which includes an annual O&M cost of $909,425 for 30 years.
PERFORMANCE STANDARDS OR GOALS: Soil will be remediated to meet State standards and
reduce the risk of additional ground water contamination. Chemical-specific clean-up
goals for soil include PCE 5 ug/kg, TCE 5 ug/kg, and toluene 100 ug/kg. Ground water
will be remediated to meet State and Federal MCLs or MCLGs including PCE 5 ug/1 (MCL),
TCE 5 ug/1 (MCL), and toluene 100 ug/1 (State).
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RECORD OF DECISION
TELEDYNE SEMICONDUCTOR AND SPECTRA-PHY81C8, INC.
JOINT SUPERFUND SITES
MOUNTAIN VIEW, CALIFORNIA
MARCH 22, 1991
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION 9
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CONTENTS
PART SECTION
I 1.0 Declaration 6
I 2.0 Statement of Basis and Purpose 6
I 3.0 Assessment of the Site .6
I 4.0 Description of the Remedy 6
I 5.0 Declaration 7
II 1.0 Site Name, Location, and Description 8
II l.l Site Name and Location 8
II - 1.2 Regional Topography 11
II 1.3 Adjacent Land Use 11
II 1.4 Historical Land Use 11
II 1.5 Hydrogeology 11
II 1.6 Water Use 13
II 1.7 Surface and Subsurface Structures 13
II 2.0 Site History and Enforcement Activities 13
II 2.1 History and Site Activities 13
II 2.2 History of Site Investigations 16
II 2.3 History of Enforcement Actions 16
II 3.0 Community Relations 17
II 4.0 Scope and Role of the Response Action 17
II 4.1 Scope of the Response Action 17
II 4.2 Role of the Response Action 22
II 5.0 Summary of Site Characteristics 22
II 5.1 Sources of Contamination 22
II 5.2 Description of Contamination 23
II 5.2.1 Soil Investigations • 23
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CONTENTS cont'd
PART SECTION PAGE
II 5.2.2 Groundwater Investigations 24
II 6.0 Summary of Site Risks . 26
II 6.1 Toxicity Assessment .26
II 6.2 Risk Characterization 31
II -6.3 Presence of Sensitive Human Populations 33
II 6.4 Presence of Sensitive Ecological Systems 33
II 6.5 Conclusion 37
II ' 7.0 Applicable or Relevant and Appropriate
Requirements (ARARs) 37
II 7.1 Types of ARARs 38
II 7.2 Contaminant-Specific ARARs 38
II 7.3 Action Specific ARARs 39
II 7.4 Location-Specific ARARs 41
II 8.0 Description of Alternatives 41
II 8.1 Teledyne Semiconductor On-Site Area "42
II 8.2 Spectra-Physics On-Site Area 43
II 8.3 Teledyne Semiconductor and Spectra-Physics
Off-Site Area 44
II 9.0 Comparative Analysis of Alternatives 45
II 9.1 Teledyne Semiconductor On-Site Area 46
II 9.2 Spectra-Physics On-Site Area 50
II 9.3 Teledyne Semiconductor and Spectra-Physics
Off-Site Area 56
II 10.0 Statutory Determinations 63
II 11.0 Documentation of Significant Changes 64
III Responsiveness Summary 65
IV Administrative Record
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LIST OF TABLES
TABLE TITLE
Soil Contaminants at the Teledyne
On-Site Area 23
Groundwater Contaminants at the Teledyne
On-Site Area 25
Groundwater Contaminants at the Spectra-
Physics On-Site Area 25
Summary of Carcinogenic Risks and Non-
Carcinogenic Risks for Study Area 34
Chemical Specific Carcinogenic and Non-
Carcinogenic Risks for Study Area 35-36
Chemical Specific ARARs 40
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LIST OF FIGURES
FIGURE TITLE PAGE
1 Teledyne/Spectra-Physics Site Location 9
2 Teledyne/Spectra-Physics On-Site Areas 10
3 Hydrogeologic Profile 12
4 Location of Teledyne Waste Storage Facilities 14
5 Location of Spectra-Physics Waste Storage
Facilities . 15
6 Location of Ground Water Extraction System 19
7 Location of Soil Vapor Extraction System 21
8 TCE Plume Definition in Shallow Zone 27
9 TCE Plume Definintion in Intermediate Zone 28
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I. DECLARATION
1.0 SITE NAME AND LOCATION
Teledyne Semiconductor, Inc.
1300 Terra Bella Avenue
Mountain View, California 94043
Spectra-Physics, Inc.
1250 West Middlefield Road
Mountain View, California 94043
2.0 STATEMENT OF BASIS AND PURPOSE
This Record of Decision ("ROD") presents the selected remedial
actions for the Teledyne and Spectra-Physics Superfund sites in
Mountain View, California. This document was developed in accor-
dance with the Comprehensive Environmental Response, Compensa-
tion, and Liability Act of 1980 (CERCLA) as amended by the Super-
fund Amendments and Reauthorization Act of 1986 (SARA), 42 U.S.C.
Section 9601 et. sea., and in accordance with the National Oil
and Hazardous Substances Pollution Contingency Plan, 40 C.F.R.
Section 300 et. seg.. ("NCP"). The attached administrative
record index (Attachement A) identifies the documents upon which
the selection of the remedial action is based.
3.0 ASSESSMENT OF THE SITE
Actual or threatened release of hazardous substances from these
sites, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial en-
dangerment to public health, welfare, or the environment.
4.0 DESCRIPTION OF THE REMEDY
The selected remedy for the Teledyne and Spectra-Physics sites
consists of:
o Soil vapor extraction for soil cleanup;
o Groundwater extraction and treatment for groundwater
cleanup;
o Shallow zone, intermediate zone, and deep aquifer ground-
water monitoring as well as soil monitoring.
These remedial actions address the principal threat remaining at
the Teledyne and Spectra-Physics sites by removing and per-
manently destroying the contaminants from soils and removing the
contaminants from ground water, thereby significantly reducing
the the toxicity, mobility or volume of hazardous substances in
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both media. These response actions will greatly reduce the pos-
sibility of contamination of existing potable water supplies and
potential future water supplies. .
S.0 DECLARATION
The selected remedy is protective of human health and the en-
vironment, complies with federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment (or resource recovery) tech-
nologies to the maximum extent practicable and satisfies the
statutory-preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as a principal element.
Because the remedy will result in hazardous substances remaining
on-site above health-based levels, a five-year review, pursuant
to CERCLA Section 121, 42 U.S.C. Section 9621, will be conducted
at 'least once every five years after initiation of the remedial
action to ensure that the remedy continues to provide adequate
protection of human health and the environment.
3.22,11
John Wi^f Date
Deputy Regional Administrator
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II. RECORD OF DECISION
DECISION SUMMARY
This Decision Summary provides an overview of the problems posed
by the Spectra-Physics/Teledyne Superfund sites ("the Study
Area"), the remedial alternatives, and the analysis of the
remedial alternatives. This Decision Summary explains the ra-
tionale for the remedy selection and how the selected remedy
satisfies the statutory requirements.
1.0 SITE NAME, LOCATION, AND DESCRIPTION
1.1- SITE NAME AND LOCATION
The Study Area (Figure 1) has been divided into the following
three areas based on the sources of contamination, the extent of
contamination in the ground water and geographic location:
Teledvne Semiconductor, Inc.. 1300 Terra Bella Avenue. Mountain
View California
Teledyne Semiconductor, Inc. (Teledyne) has owned and operated a
semiconductor manufacturing facility at 1300 Terra Bella Avenue
since 1962, (Figure 2). The southern half of the facility was
built in 1962 and the northern half of the building was added in
1966.
Spectra-Physics. Inc., 1250 West Middlefield Road. Mountain View
California
Spectra-Physics is an active manufacturer of lasers and as-
sociated components which has operated two of its divisions,
Laser Products and Optics, in the City of Mountain View since
1961. Seven of the nine buildings in Spectra-Physics' Mountain
View facility are bounded by West Middlefield Road, Terra Bella
Avenue, and Shoreline Boulevard (formerly Stierlin Road) (Figure
2). The other two buildings are on the north side of Terra Bella
Avenue.
Teledyne/Spectra-Physics Combined Study Area
The Teledyne/Spectra-Physics Combined Study Area (the "Study
Area") encompasses the full extent of the groundwater plume and
is generally bounded by Permanente Creek to the west, the City of
Mountain View dewatering trench to the north, Armand Avenue to
the east, and Teledyne and Spectra-Physics facilities to the
south (Figure 1).
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1
1
>/fc^
u>
"ELEDYNE/SPECTRA PHYSICS OFF SITE)
Mountain View • San
, /- Sunnyvale :
MAP
TELEDY
SEMICONDUCTOR
SPECTRA PHYSICS ON SITE AREA
Iterate* LBV
"\ Engine«fS
R« FIGURE 1: TELEDYNE/ SPECTRA-PHYSICS
T« SUPERFUND SITE
FIGURE l: STUDY AREA
ORIGINAL
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[ : ii \Uf fL' injff
- ' *
IIAI
FIGCTLB 2: TELEDYKB SEMICONDUCTOR AND 6PECTRA-PEYSIC8_ON-
ARBAfl
limi
9IC8 OK-SITE
POOR Qu AH
ORIGINAL
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1.2 REGIONAL TOPOGRAPHY
The Study Area is located in the Santa Clara Valley which is a
gently-sloping alluvial plain, flanked by the Diablo Range to the
east-southeast and the Santa Cruz Mountains to the west-
southwest. The Study Area is located toward the center of the
valley. The Santa Cruz Mountains are located several miles
southwest of the Study Area. The San Francisco Bay is located
approximately 3 miles north of the Study Area.
1.3 ADJACENT LAND USE
The Study Area consists of a mixture of commercial/industrial
buildings (about 57 percent), residential land use (about 8
percent), and public buildings and land uses (about 35 percent).
The Study Area contains a network of paved streets with sidewalks
and landscaping. There are two open spaces within the Study
Area: one is the playground and softball field associated with
Crittenden Middle School immediately west of the on-site areas,
and the other is the open space adjacent to the present City of
Mountain View Landfill and Shoreline Amphitheater.
1.4 HISTORICAL LAND USE
Historical aerial photographs show that historical land use
within the Study Area was agricultural, dating back to 1937 and
possibly further. The Study Area was developed as an industrial
area during the period from 1961 to 1973. Companies historically
located in the vicinity of the Study Area were involved in a wide
range of manufacturing activities, including the manufacturing of
amusement park equipment, laser devices, printed circuit boards,
electrical test equipment, and semiconductors. In addition to
commercial and agriculture use, the Study Area includes residen-
tial use.
1.5 HYDROGEOLOGY
Ground water zones at the Study Area are divided into an Upper
Aquifer Zone and a Deep Aquifer Zone (Figure 3). The Upper
Aquifer Zone is divided into the Shallow Zone and the Inter- "
mediate Zone. The Shallow Zone is about 10 feet thick, and
generally occurs between the depths of 10 to about 30 feet below
ground surface. The Intermediate Zone is about 10 to 15 feet
thick, generally occurring between the depths of 35 to 70 feet
below ground surface. The Upper Aquifer Zone and the Deep
Aquifer Zone are separated by a Confining Zone composed primarily
of silt which varies in thickness from about 50 to 150 feet. The
Deep Aquifer Zone is generally more than 150 feet below ground
surface. Groundwater elevations in the Study Area indicate a
northerly flow direction in the Upper Aquifer Zone.
11
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CENJLRp^,IZED GENERALIZED
LITHOLOCY
5-20
20-30
30-40
70-80
150±
EXPLANATION
Cl»y
Silt
Send
Gravel
DESCRIPTION
— — -
— — —
—
—
_ -_ _
__
i-:.-. •*:•:•"•:':•/
#£#2:
&p§
-./ —
y ^
—
—
^ —
— —
— • —
—
—
/:*-:T- vV-
*•• '•.•>•. .-•'•
e •.;•_•.• • .--.
f •':•'*. ''A* -:.
-.:;-e:.-.-.v*.-
:®-:::^^
~1_T~— .
• ^—. '_ «•
'.>'--^':;
. .^ ^^^ . • .
"• * V'"*""- * • '
?-•:*•/••.:
:»!-?JM:
* • •
::v..v;:.-».
jV :*.>:•:..•.
xfitf^
ee.
ut
_)
<
K
LU"
O.
D
SILT AND CLAY (generally unsaturated)
SHALLOW ZONE
•
UPPER CONFINING ZONE
INTERMEDIATE ZONE
*
LOWER CONFINING ZONE
DEEP AQUIFER
»
.
(not to scale)
Figure 6 : GENERALIZED STOAflGRAPHIC COLUMN
FIGUKX 3s HYDROGEOLOGXC PROFILE
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Elevations in the Shallow and Intermediate Zone sediments
demonstrate an upward hydraulic gradient between the two zones.
.Groundwater elevations within the Study Area also show an upward
hydraulic gradient from the Deep Aquifer to the Upper Aquifer.-
1.6 WATER USE
Historical ground water use in the Study Area includes private
water-supply wells for homes and agriculture prior to the con-
struction of public water connections and sewer connections in
1984. A review of data on active, abandoned and closed wells
within the Study Area identified 174 registered wells, including
former private water-supply wells. Of these, 120 are equal to or
greater than 65 feet deep, or of unknown depth. Of the 120
wells, 13 are active, seven are inactive, 31 are destroyed, and
69 "are abondoned. Based on the results of this investigation,
wells identified in the North Bayshore Area which exceed 80 feet
in depth and contained VOCs were closed as a precautionary
measure.
1.7 SURFACE AND SUBSURFACE STRUCTURES
Teledyne used two double staged equalization sumps to separate
TCE from waste discharge, sumps B/C and D (Figure 4). Teledyne
also used a 2000 gallon underground tank, Tank A, to store waste
solvents, i.e. isopropyl alcohol, xylene, and acetone. An above
ground storage tank was used to store unused TCE, Tank B.
Spectra-Physics has no record of using underground facilities to
store hazardous substances on their site. However, there are
records of two underground gasoline tanks and five underground
sumps. Spectra-Physic's records indicate that two 3,000-gallon
underground gasoline tanks, used by prior occupants, previously
were located on the Spectra-Phyiscs site. The records do not
show use of the tanks for anything but gasoline storage. The
gasoline tanks were removed in 1985. Until 1987, the waste
streams to the sanitary sewer from Buildings 2, 3, 4, 4A and 5
passed through underground neutralization sumps (Figure 5).
2.0 SITE HISTORY AMD ENFORCEMENT ACTIVITIES
2.1 HISTORY OF SITE ACTIVITIES
Teledyne has operated a semiconductor manufacturing facility at
its Mountain View facility since approximately 1963. Teledyne
installed two 1400 gallon below-grade sumps at their site in 1962
and 1966, respectively. Prior to 1980, the sumps were used for
acid neutralization and waste TCE collection. Neither sump has
contained TCE since 1980 and the two sumps are no longer in serv-
ice. A 2,000 gallon underground waste flammable solvent tank
13
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15*7?
Illiniu
WASTEWATER DRAIN UNE
(In concrete trench)
ABANDONED
SOLVENT
DRAINAGE UNE
(in concrete
trench)
WASTEWATER
DRAJN UNE7
CONCRETE TRENCH
ABOVE GROUND
TCETANK
son
Sample
Location
• Background
Sol
Sample
Location
TANK A (removed In 1982)
Note: J.K. NtinfeUw & Associate*, 1983
50 lOOfl
T»<«dyn« Samieenduder Facilty.
MeuntaM View, CaTrfomU, Aueuct 26
Locations of Sumps, Drain Lines, and 1983 Soli Samples
Remedial Investigaiion/FeasiWity Study
Teledyne Semiconductor . •
Wruintain V!«w California .
PIGURB 41 LOCATION OP TELEDYKE WASTE STORAGE PACILITIES
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tOOO-GafcnSump
Installed in 1974
Removed in 1987 _
Hazardous
Material
Storage Area
3000-Gafion Gasok>«
Storage Tank
(Underground )
InsiaBed in 1976
Removed in 19SS
O
"C
O
Q:
Q
-j
UJ
ul
UJ
-J
Q
Q
1000-Galon Sump
Inaalled in 1977
Removed in 19^
Hazardous
Material
Storage Area
Manual sliding
chain-link
locked
(padlock) fence
I
1000-Gaflon Sump
Installed in 1977
50-GaDonSump
(Use CMS*} 1974)
lnstaBedt968
Removed 1967
Manual sliding
chain-link locked
(padlock) fence
1000-GaJon Sunp
hsJa)led«i1971
Remowdin 1967
©
LIST Of BlllLniNCS:
1 - 12«ii li-rr.i Kcl I.'
3 - 12&0 tf. Miqdlof itrlU
* - 1330 W. Kiddlefield
«.A • mo v. Middlefiold
S • 13SO *. Middicf.-Id
6 - I3«»* Jerrt Bella
7 - 1327/
1335 Terr.. D-lla
1S - 1310 Terra Bell*
18 - 1305 Terr* Bella
EXPLANA1 I ON
• Hazardous, material/
waste storage
facilities
9 Emergency clottimg/
respirators (SCBA)
0 Absorbent material
for spilIs;
Command Post
(Emergency Response
Teat)
ENS Eye Mash/Snower
•*— Waste-ater Piping
0 100 200 300 feet
Figure C-1 : DETAILED SHE PLAN
FIGTJRE 5: LOCATION OF SPECTRA-PHYSICS WASTE STORAGE FACILITIES
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(Tank A) was installed in 1975 and removed in 1982. It was used
to store waste isopropyl alcolhol, xylene and acetone. Teledyne
also used TCA and other VOCs at the facility. All underground
solvent handling activities were discontinued in 1980 and all
chemicals are currently stored above-ground.
Since approximately 1963, Spectra-Physics has manufactured lasers
and associated components at its Mountain View facility.
Spectra-Physics previously used five underground sumps as part of
its industrial wastewater disposal system (see Section 1.7). One
50 gallon and four 1000 gallon underground sumps were installed
between 1968 and 1977. Rinsewaters were discharged through these
sumps to the sanitary sewer for the primary purpose -of pH and
flow equalization. All but one of the sumps were removed in
1987. The remaining sump is primarily used for settlement of
solids. Spectra-Physics used TCE, TCA, Freon-113 and other
volatile organic compounds (VOCs) in its manufacturing processes.
2.2 HISTORY OP SITE INVESTIGATIONS
In 1982, Teledyne and Spectra-Physics submitted Facility Ques-
tionnaires to the California Regional Water Quality Control Board
(RWQCB) staff describing their underground neutralization sys-
tems, sumps, and tanks. Based on these submittals, staff re-
quired the initiation of a remedial investigation (RI) at
Teledyne in 1982 and Spectra-Physics in 1984. The RI has been
ongoing for the last eight years. Sampling results from these
investigations are described in Section 5.2. Teledyne and
Spectra-Physics have jointly and separately implemented interim
remedial actions since remedial investigations were initiated.
These interim actions are described in Section 4.1.
2.3 HISTORY OP ENFORCEMENT ACTIONS
Teledyne and Spectra-Physics are on the National Priorities List
(NPL). The sites have been regulated by the RWQCB Orders since
1986. The summary of enforcement history for each of the sites
is as follows:
Teledyne
o February 1986 - Order No. 86-9, Waste Discharge Requirements
o June 1986 - Teledyne Semiconductor site is added to the NPL
o September 1986 - Cleanup and Abatement Order No. 86-011
o January 1987 - Cleanup and Abatement Order No. 87-002
o January 1989 - Order No. 89-019, Site Cleanup Requirements
Spectra-Physics
o February 1986 -Order No. 86-10, Waste Discharge Requirements
o September 1986 - Cleanup and Abatement Order No. 86-012
o January 1987 - Cleanup and Abatement Order No. 87-003
16
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o June 1988 - Spectra-Physics site proposed for NPL
o January 1989 - Order No. 89-020, Site Cleanup Requirements
3.0 COMMUNITY RELATIONS
The RWQCB has maintained an aggressive Community Relations
program for the Teledyne and Spectra-Physics sites. The RWQCB
published a notice in the The View (Mountain View Newspaper) on
November 1, 1990, announcing the proposed final Remedial Action
Plan (RAP) and announcing the public meeting held on November 14,
1990. A presentation of the final cleanup plan was made at the
November 14., 1990 public meeting. The comment period for the
proposed cleanup plan was from November 14, 1990 to December 28,
1990. The Responsiveness Summary for the comments received
during this period are included as Part III of this document.
Fact sheets were mailed to interested residents, local government
officials, and media representatives. Fact sheet f 1, mailed in
August 1989, summarized the pollution problem, the results of .in-
vestigations to date, and the interim remedial actions. Fact
sheet # 2, mailed in November 1990, described the cleanup alter-
natives evaluated, explained the proposed final RAP, announced
opportunities for public comment at the Regional Board Hearing of
November 14, 1990 in Oakland and the Public Meeting of November
14, 1990 in Mountain View, and described the availability of fur-
ther information at the Information Respository at the Mountain
View Public Library. Fact sheet # 3, mailed in March 1991, ex-
plains the final Cleanup and Abatement Order adopted by the
RWQCB.
4.0 SCOPE AND ROLE OF THE RESPONSE ACTION
4.1 SCOPE OF THE RESPONSE ACTION
The remedy selected and described in this ROD includes existing
interim remedial actions as well as additional remedial actions
selected for the Teledyne and Spectra-Physics sites. The interim
remedial actions include the removal of leaking underground sumps
and tanks, excavation of contaminated soil, three groundwater ex-
traction systems, the operation of the City of Mountain View
dewatering trench, and a soil vapor extraction system. The addi-
tional remedial actions include the expansion of existing
groundwater extraction systems and the soil vapor extraction sys-
tem and additional ground water and soil monitoring.
Spectra-Physics removed four sumps suspected of leaking at its
site. In 1987, the sumps were removed and six feet of soil sur-
rounding the sumps was excavated to a depth of two feet below the
bottom of the sumps. As a result of an investigation in
February 1986, Spectra-Physics was ordered to remove four of
their five sumps. Listed below and shown in Figure 5 are the
sumps the RWCQB ordered Spectra-Physics to remove in order to
eliminate potential sources of contamination:
17
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o Three-stage equalization sump, 1250 West Middlefield
Road, Building 3 installed in 1971 and removed in
December 1987;
o Three-stage equalization at 1340 West Middlefield Road,
Building 4A installed in 1977 and removed in December
1987;
o Four-stage equalization sump at 1340 West Middlefield
Road, Building 4A installed in 1977 and currently in
use;
o Four-stage equalization sump at 1350 West Middlefield
Road, Building 5 installed in 1974 and removed in
December 1987;'
o One-stage equalization sump at 1245 Terra Bella Road,
Building 2 installed in 1968 and removed in April 1987.
The sump remaining at Building 4A is used primarily for solids
settlement, and is secondarily contained.
Teledyne removed Tank A and excavated the surrounding con-
taminated soils in August 1982. Teledyne ceased using sumps B/C
and D in 1987 when a new above ground, double-contained, acid
neutralization system was put on line. Sumps B/C and D were not
removed from the subsurface.
Three groundwater extraction systems were installed on the
Teledyne site and in the combined Teledyne and Spectra-Physics
Study Area. Teledyne has an extraction system operating on their
site which consists of a Shallow Zone extraction well and an In-
termediate Zone extraction well. This extraction system has been
operating since October 1986. In addition, Teledyne and
Spectra-Physics have installed groundwater extraction systems
along Spring Street and in the North Bayshore area (Figure 6).
The Spring Street Extraction System (SSES), consists of three
Shallow Zone and two Intermediate Zone extraction wells and was
developed to capture concentraions of VOCs greater than 0.1 ppm.
This extraction system has not yet started operating. The North
Bayshore Extraction System (NBES) consists of eleven Shallow Zone
and six Intermediate Zone extraction wells. The system started
operating on January 4, 1990 and the entire NBES was operating
continuously as of March 13, 1990. The NBES was designed to
capture VOCs in concentrations greater than 5 ppb in the Upper
Aquifer Zone. Extracting ground water from the Upper Aquifer
Zone minimizes the risk of VOCs migrating downward by enhancing
the upward gradients between the Deep and Upper Aquifer. The
operating extraction systems are currently discharging extracted
water to the sanitary sewer system under permit.
18
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FIGURE 6: LOCATION OF EXTRACTION SYSTEMS
ORIGINAL
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The 150-acre parcel of the City of Mountain View landfill was ex-
cavated below sea level during construction in 1978. A dewater-
ing trench was installed to dewater the excavation until the •
refuse was filled above sea level. The landfill dewatering
trench, which borders the landfill parcel located directly north
of Amphitheatre Parkway between Pennanente Creek and North
Shoreline Blvd. (Figure 6), has been and continues to be operated
by the City of Mountain View on a voluntary basis to assist in
keeping ground water in the Upper Aquifer under hydraulic control
until the NBES is completed. The NBES will be designed to
remediate the groundwater plume once the trench is turned .off.
The SSES was installed to shorten the overall remediation time by
removing a"higher concentration of VOCs.
Spectra-Physics installed a soil vapor extraction system (SVES)
near Building 3 (Figure 7) to reduce the concentration of VOCs in
the soils. The SVES consists of three extraction wells which
penetrate 12 feet into the soil. A partial vacuum is applied to
the"wells which extracts vapors containing VOCs and passes the
vapors through activated carbon cannisters.
The selected remedy for the sites consists of:
o Groundwater extraction and treatment for groundwater
cleanup;
o Soil vapor extraction and treatment for soil cleanup;
o Shallow zone, intermediate zone and deep aquifer groundwater
monitoring and vadose zone monitoring.
The selected remedy for the Teledyne site consists of continuing
the current groundwater extraction system, treating contaminated
water with an air stripper, and discharging under NPDES permit to
the storm drain. The air stripper will include air emission con-
trol with vapor phase carbon if emissions exceed levels permitted
by the Bay Area Air Quality Management Board.
The selected remedy for the Spectra-Physics site consists of ex-
panding the soil vapor extraction system to include soil vapor
extraction in four additional areas. Groundwater remediation
will be provided by the Teledyne On-Site extraction and treatment
system.
The selected remedy for the Study Area consists of continuing
operation of the current groundwater extraction systems with a
contingency for additional extraction wells if complete capture
is not achieved when the City of Mountain View landfill dewater-
ing system pump is turned off. Ground water extracted from the
NBES will be discharged under permit to the city sewer system.
Ground water extracted from the SSES will either be treated with
the air stripper unit at the Teledyne facility and discharged un-
der NPDES permit to the storm drain or discharged under permit to
the city sewer system.
20
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Wo*t Middl»fl*id Road •' .
•J Eating •*••(•» Ml
i bound! ol tee
ceramnfeni el VQGt grasiw ow IS pe»>
FIGURE 7: SOIL VAPOR EXTRACTION SYSTEM
POOR QUALITY
ORIGINAL
-------
4.2 ROLE OF TEE RESPONSE ACTION
The selected remedy addresses the principal threats posed by the
contamination in soils and ground water in the the Upper Aquifer
Zone. These principal threats are: further lateral migration of
the plume emanating from the Teledyne and Spectra-Physics sites;
potential vertical migration of contaminated ground water into
the Deep Aquifer Zone; ingestion and inhalation of contaminants
in the ground water from the Upper Aquifer Zone; ingestion and
inhalation of contaminants in the contaminated soil; and inhala-
tion of chemicals volatalized from contaminated ground water.
The objective of the selected remedy is to remove and permanently
destroy the contaminants from both soils and ground water or sig-
nificantly reduce the toxicity, mobility or volume of hazardous
substances in both media. These response actions will greatly
reduce the possibility of contamination of current and potential
wate'r supplies.
5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 SOURCES OF CONTAMINATION
In its waste management process/ Teledyne used two double staged
equalization sumps to separate TCE from its waste discharge,
sumps B/C and D. Teledyne also used a 2000 gallon underground
tank, Tank A, to store waste solvents, i.e. isopropyl alcohol,
xylene, and acetone. An above ground storage tank was used to
store unused TCE, Tank B. The location of the sumps and tanks
are shown in Figure 4. Soil investigations conducted during 1982
through 1983 and 1988 through 1989 detected the
release of chemicals from sumps B/C and D and former Tank A.
Spectra-Physics managed solvent wastes by discharging waste water
to buried equalization sumps which discharged into the sanitary
sewer. A series of soil investigations conducted since 1984 have
shown that a release of chemicals has occurred at the Spectra-
Physics site. As a result of an investigation in February 1986,
Spectra-Physics was ordered to remove four of its five sumps.
Removal of the sumps revealed that a tree root had punctured a
drainage line a few feet upstream of the sump at Building 3.
Soil investigations further concluded that almost all contamina-
tion originated at the punctured drainage line.
The contamination in the combined study area is primarily in the
Shallow Zone and partially in the Intermediate Zone of the Upper
Aquifer. This comingled groundwater plume is attributed to
Teledyne and Spectra-Physics because of the releases of chemicals
from their waste handling facilities.
22
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5.2 DESCRIPTION OF CONTAMINATION
5.2.1 SOIL INVESTIGATIONS
Soil investigations conducted at the Teledyne facility identified
volatile organic compounds (VOCs) in the soils. Samples col-
lected at the former location of Tank A (Figure 4) were found to
contain 1,2-dichloroethylene (1,2-DCE), trichloroethene (TCE),
and toluene. The maximum concentrations detected were 18 parts
per billion (ppb) of 1,2-DCE, 79 ppb TCE, and 21 ppb toluene.
Samples collected from the location of Sump D were found to con-
tain toluene, TCE, 1,2-dichloroethane (1,2-DCA), and 2-butanone.
Maximum concentrations of VOCs detected were 14 ppb toluene, 40
ppb TCE, 5.7 ppb 1,2-DCA, and 23 ppb 2-butanone. Samples col-
lected from the location of Sump B/C detected 2-butanone, TCE,
tetrachlorethylene (PCE) and toluene. The maximum concentrations
detected in soil samples at Sump B/C were 32 ppb 2-butanone, 160
ppb TCE, 5.7 ppb PCE, and 46 ppb toluene. Further analyses of
these soil samples determined that the priority pollutant metal
concentrations in soils are generally within the range of ex-
pected background levels. The results of soils investigations
conducted at the Teledyne facility are summarized in Table 1.
LOCATION 1,2-DCA TCE TOLUENE 2-BUTANONE 1,2-DCA PCE
(PPb)
TANK A
SUMP D
SUMP B/C
18
**
**
79
40
160
21
14
46
**
23
32
**
5.7
**
**
**
5.7
TABLE 1: Soil Contamination at the Teledyne On-Site Area
Since 1984, soil samples were collected from more than 68
boreholes drilled on the Spectra-Physics site. Additionally,
soil samples were collected from the side and bottoms of the pits
which remained after the four former sumps were removed, and a
soil gas survey was conducted during 1989 in the vicinity of
Building 2 and 3 in order to assess the lateral extent of soils
containing VOCs in the area. The primary volatile organic com-
pounds detected in soil are TCE and 1,2-DCE. Soil samples col-
lected from an area adjacent to the sump near Building 3 were
23
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found to contain up to 18 parts per million (ppm) TCE and up to l
ppm toluene. TCE is found in the highest concentrations and over
the greatest area. Concentrations of TCE in soils in excess of
2.5 ppm have been detected in soils in the loading dock area,
soils in a small area east of Building 2, soils in a small area
west of Building 2, and soils below the former Building 3 sump.
Figure 7 indicates where VOC concentrations in soils exceed 2.5
ppm within the Spectra-Physics On-Site area.
5.2.2 GROUNDWATER INVESTIGATIONS
To evaluate, the distribution of VOCs in ground water immediately
adjacent to the Teledyne facility, 21 Shallow Zone monitoring
wells, 10 Intermediate Zone monitoring wells, and 1 vertical ex-
tent well were installed.' The distribution of TCE in the Upper
Aquifer is described in Figures 8 and 9. Seven VOCs have been
regularly detected in the Shallow Zone since monitoring started
in 1982: TCE; 1,2-DCE; TCA; 1,1-DCE; 1,1-DCA; Freon 113; PCE; and
vinyl chloride. TCE has been found at more sampling points and
at generally higher concentrations than the other chemicals. TCE
in the Shallow Zone ground water at and immediately downgradient
of Teledyne has ranged from less than 1 ppb to 9800 ppb. TCE
concentrations in the Intermediate Zone has ranged from less than
1 ppb to 9800 ppb. A vertical extent well detected TCE at 60
feet below ground surface at concentrations ranging from less
than 0.5 ppb to 9.6 ppb in September 1988, however, no VOCs have
been detected in this well since that date. Table 2 summarizes
the range of contaminant levels in the Upper Aquifer at the
Teledyne On-Site area.
Spectra-Physics has installed 17 shallow zone monitoring wells
and three intermediate zone monitoring wells within their
property boundaries to assess the lateral and vertical extent of
contaminants. Five VOCs have been regularly detected during pre-
vious studies in Upper Aquifer ground water: TCE; trans-l,2-DCE;
1,1,1-trichloroethane ( 1,1,1-TCA); 1,1-dichloroethane (1,1-DCA);
and 1,1-dichloroethylene (1,1-DCE). TCE has been found at more
sampling points and at generally higher concentrations than the
other chemicals. TCE in Shallow Zone ground water at and im-
mediately downgradient of Spectra-Physics has ranged from less
than 1 ppb to 2700 ppb. TCE concentrations in Intermediate Zone
ground water has been at or near non-detectable concentrations,
but have recently increased at one well to 1 ppb. Also in the
Shallow Zone, concentrations of trans-l,2-DCE have ranged from
less than 5 ppb to 286 ppb. Freon 112 has been detected at con-
centrations ranging from 1 ppb to 16 ppb. Concentrations of
1,1-DCA have ranged from less than 5 ppb to 270 ppb and con-
centrations of 1,1-DCE have ranged from less than 5 ppb to 240
ppb. The highest concentrations of VOCs in ground water at the
Spectra-Physics facility generally occur in the area of the
former Building 3 sump. Table 3 summarizes the ground water data
for the Spectra-Physics site.
24
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Aquifer
Zone
TCE
12-DCE
Contaminants (ppb)
lll-TCA ll-DCA
11-DCE
Shallow ND - 9800 ND - 4200 ND - 10
Upper Int.ND - 9800 ND ND
Lower Int.ND - 550 ND ND
ND - 0.7 ND - 4.9
ND ND
ND ND
Aquifer
Zone
FREON 113
Contaminants (ppb)
PCS
VINYL CHLORIDE
Shallow ND - 200
Upper Int. ND - 110
Lower Int. ND - 5
ND - 100
ND - 5
ND - 36
ND
ND
ND
- 770
TABLE 2: Groundwater Contaminants at the Teledyne On-Site
Area
Aquifer Contaminants (ppb)
Zone TCE tl2-DCE lll-TCA ll-DCA 11-DCE
Shallow 5 - 2700 5 - 286
Upper Int. ND ND
Lower Int. ND ND
ND 5 - 270 5 - 2400
ND ND ND
ND ND ND
TABLE 3: Ground Water contaminants at the Spectra-Physics
On-Site Area
25
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To assess the lateral and vertical extent of contamination in the
ground water extending, beyond the boundaries of the facilities,
Teledyne and Spectra-Physics installed over 100 shallow and in-
termediate zone monitoring and extraction wells, two deep aquifer
monitoring wells, and three vertical extent monitoring wells.
The horizontal extent of contamination in the Upper Aquifer Zone
is defined to the north at approximately the City of Mountain
View dewatering trench, to the east and west at approximately Ar-
mand Avenue and Permanente Creek, respectively. _The vertical 'ex-
tent of groundwater pollution extends approximately to the top of
the regional aquitard. Figures 8 and 9 illustrate the boundaries
of the TCE plume in the Shallow and Intermediate zones.
6.0 SUMMARY OF SITE RISKS
6.1 TOXICITY ASSESSMENT
Nine indicator chemicals were identified from approximately 30
chemicals detected in the Study Area. The nine indicator chemi-
cals are as follows:
1,1-dichloroethane (1,1-DCA)
1,1-dichloroethylene (1,1-DCE)
1,2-dichloroethylene (1,2-DCE)
tetrachloroethylene (PCE)
toluene
1,2,4-trichlorobenzene (1,2,4-TCB)
1,1,1-trichloroethane (1,1,1-TCA)
trichloroethylene (TCE)
vinyl chloride (VC)
The rational for selecting the listed chemicals as indicator
chemicals is as follows:
l.l-Dichloroethane fl.l-DCA)
o 1,1-DCA has been detected in wells throughout the Study Area
in both the Shallow Zone and the Intermediate Zone;
o 1,1-DCA was detected in 8.1% of the soil samples collected
within the Study Area;
o 1,1-DCA possesses physiochemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
o 1,1-DCA was identified by EPA as a probable human carcinogen
(Group B2) based on available laboratory animal data.
1.1-Dichloroethvlene fl.1-DCE)
o 1,1-DCE has been detected in wells throughout the Study Area
in both the Shallow Zone and Intermediate Zone;
26
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O.OOSppm
UopUtfclor
TCE
0.100 ppm
Uoplethfor
TCE
Are« of Captcr«
North Bcythen
Extncttoa *r*ua
Area of Captar*
Extrmctioa trtMrn
FIGURE 8S TCE FLUKE IN SHALLOW ZOHZ
LtVINE'FRICKE^ ...
— VooftQUAU
ORIGINAL
-------
Area of Captar*
North Baj«bar«
Extraction *T«em
FIGURZ ft TCS FLUKE IN IKTERKEDIATB 2ONZ
ORIGINAL
r
-------
o 1,1-DCE was detected in 7.0% of the soil samples collected
within the Study Area;
o 1,1-DCE possesses physiochemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
o 1,1-DCE was identified by EPA as a possible human carcinogen
(Group C) based on available laboratory animal data.
1.2-Dichloroethvlene (1.2-DCE)
o 1,2-DCE has been consistently detected in wells throughout
the Study Area in both the Shallow Zone and Intermediate
Zone;
o 1,2-DCE was detected in 21.0% of the soil samples collected
within the Study Area;
o 1,2-DCE possesses physiochemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
1.1.2.2-Tetrachloroethvlene (PCE)
o PCE has been consistently detected in wells throughout
the Study Area in both the Shallow Zone and Intermediate
Zone;
o PCE was detected in 21.0% of the soil samples collected
within the Study Area;
o PCE possesses physiochemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
o PCE was identified by EPA as a probable human carcinogen
(Group B2) based on available laboratory animal data.
Toluene
o Toluene was detected in 9.7% of the soil samples collected
within the Study Area;
o Toluene has a relatively low soil sorption coefficient,
therefore, has the potential to leach from soil into ground-
water;
o RWQCB requested this chemical be included as an indicator
chemical.
1.2.4-Trichlorobenzene (1.2.4-TCB)
o 1,2,4-TCB was 1.1% of the soil samples collected within the
29
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Study Area;
o RWQCB requested this chemical be included as an indicator
chemical.
1.1.l-Trichloroethane (1.1.1-TCA1
o 1,1,1-TCA has been consistently detected in wells throughout
the Study Area in both the Shallow Zone and Intermediate
Zone;
o 1,1,1-TCA was detected in 16.7% of .the soil samples
collected within the Study Area;
o PCE possesses physicchemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
Trichloroethylene (TCE)
o TCE has been consistently detected in wells throughout
the Study Area in both the Shallow Zone and Intermediate '
Zone;
o TCE was detected in 72.6% of the soil samples collected
within the Study Area;
o TCE possesses physiochemical properties (relatively high
water solubility and relatively low soil sorption) which
tend to promote its dispersion in ground water;
o TCE was identified by EPA as a probable human carcinogen
(Group B2) based on available laboratory animal data.
Vinvl Chloride (VC)
o Vinyl chloride has been detected infrequently and sporadic-
ally throughout the Study Area in both the Shallow Zone and
the Intermediate Zone;
o Vinyl chloride has been detected in one soil sample to date;
o Vinyl chloride possesses physiochemical properties (relat-
ively high water solubility and relatively low soil
sorption) which tend to promote its dispersion in ground
water;
o Vinyl chloride was identified by EPA as a confirmed human
carcinogen (Group A) based on evidence in humans; it is also
an established animal carcinogen.
30
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6.2 RISK CHARACTERIZATION
Exposure pathways were identified and evaluated for both the cur-
rent land-use condition and for hypothetical future land-use con-
ditions. Assessment of potential risk under the current land-use
scenario was conducted to determine the degree that chemical
residues currently present in soil and groundwater in the Study
Area may impact the health of humans who currently live or work
in the Study Area. Assessment of potential risk under the future
land-use scenario was conducted with the assumption that the
Study Area, including the location of the facilities, is con-
verted into.a typical residential area and the population can use
the Upper Aquifer ground water as a domestic potable water
supply.
Through a process of identifying and evaluating all of the poten-
tial exposure pathways associated with the contamination in the
Study Area, those pathways which are complete are identified. A
complete exposure pathway is one that has all the necessary com-
ponents: a source and mechanism of chemical release; an environ-
mental transport medium, a potential human exposure point, and a
likely route of exposure. The exposure pathways which were
determined to be potentially complete for current land use and
future land use are as follows:
o Possible inhalation of ambient air in the vicinty of the
manholes along the sanitary sewer line into which indicator
chemicals may have volatilized after discharge of extracted
ground water into the sanitary sewer line.
o Exposure to indicator chemicals due to use (as potable
water) of ground water extracted from wells (existing or
future installations) screened into the Upper Aquifer;
potential exposure pathways include ingestion, dermal con-
tact, and inhalation of vapors (e.g., showering);
o Possible inhalation of indoor residential air containing
indicator chemicals that may have volatilized from con-
taminated ground water and/or soil.
To assess the potential risk associated with volatilization of
indicator chemicals from the sanitary sewer system, air samples
were collected at locations in the Study Area where greatest em-
missions would occur, "worst case conditions." TCE was the only
indicator chemical detected in ambient air, therefore, TCE was
the only chemical considered in measuring this risk. The highest
8-hour concentration was 0.430 ppb which was collected at night.
The human receptors most likely to be exposed to TCE volatalized
from the sewer line are:
o utility workers who may periodically enter the manhole;
o residents in nearby homes.
31
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To judge the potential health implications for each of these
groups due to airborne TCE, measured exposure point concentra-
tions were compared with regulatory criteria. For residents, an
exposure point concentration of 0.00104 mg/m , which was con-
sidered the worst case concentration, is about 15% of the
health-based California Applied Action Level (AALair) for TCE
(0.007 mg/m3). For the utility worker, the maximum exposure
point concentration was estimated to be 0.230 mg/m3, which is
based on the findings of the air sampling study and adjusted
using a 100-fold safety factor. This exposure point concentra-
tion is only a fraction (0.085%) of OSHA's 8-hour time weighted
average for TCE in air, which is 50 ppm or 270 mg/m3.
Average-case and maximum-case theoretical upperbound carcinogenic
risks for both residents and utility workers were estimated. Ex-
posure assumptions were developed for both cases and for both
potential receptors in order that chemical intakes (daily dose)
could be estimated. Based on the sampling study, the 95% upper
bound cancer risk rate for residents was calculated to be 6.5 x
10~10 (average case) and 6.9 x 10"' (maximum-case). For the
utility worker, theoretical upperbound cancer risk rates were es-
timated to be 7.8 x 10"8 (average case) and 1.1 x 10~6 (maximum
-case). These risks are within EPA's target risk range of l x
10~4 to l x 10~6.
To assess the potential risk associated with migration of in-
dicator chemicals from ground water into residential air, a study
including a combination of field measurements and analytical
modeling was conducted on the Study Area. Emission rates were
determined using the EPA-recommended surface isolation flux cham-
ber. Gas samples were collected and analyzed for specific in-
dicator chemicals known to be present in ground water. Sampling
locations selected to provide worst-case emissions, were above
areas where the highest VOC concentrations (1,1,1-TCA and TCE)
were detected in ground water.
Soil vapor emission rates were determined and estimates of indoor
air VOC concentrations were calculated using a steady-state,
single-compartment model. Construction parameters conservatively
representative of homes in the off-site area were considered in
deriving both hypothetical, average-case and maximum-case indoor
air concentration estimates. Using the estimated concentrations
(i.e., exposure point concentrations) and assumed exposure fac-
tors representative of indoor residential activity, chronic daily
intakes (GDIs) were estimated for potentially carcinogenic (TCE).
and noncarcinogenic-chemicals (1,1,1-TCA and TCE). Hypothetical
average-case and maximum-case upperbound carcinogenic risks as-
sociated with these emissions were found to be 5.6 x 10~6 and 1.9
x 10~5, respectively. Hypothetical average-case and maximum-case
noncarcinogenic risks were found to be HI=0.18 and HI=0.18,
respectively.
32
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For determining the average-case carcinogenic and noncar-
coninogenic risks associated with the hypothetical use of ground
water from the Shallow or Intermediate Zones, domestic usage of
Shallow Zone water combined with other less significant exposure
pathways (e.g., volatilization of VOCs from soil into ambient
air, hypothetical volatilization from ground water into indoor
air, and leaching of VOCs from the soil into ground water) were
assumed. The chemicals contributing the majority of the risk are
1,1-DCE, TCE, and VC. The noncarcinogenic risks are pre-
dominately attributed to 1,2-DCE and TCE. Assuming domestic
usage of Intermediate Zone ground water along with other less ex-
posure pathways, TCE accounts for the majority of both the car-
cinogenic and noncarcinogenic risk.
Maximum-case carcinogenic and noncarcinogenic risks were summed
for all exposure pathways and chemicals, which assumes that all
of the maximum exposure concentrations occur simultaneously in
the -same well. Most of the carcinogenic risk associated with
hypothetical maximum exposure is attributed to VC, which has been
found in only 6 of 115 wells in the Study Area.
Summary of average-case and maximum-case carcinogenic and noncar-
cinogenic risks associated with current and hypothetical future
land-use conditions in the Study Area are given in Tables 4 and
5.
6.3 PRESENCE OF SENSITIVE HUMAN POPULATIONS
Approximately 8% of the Study Area is residential and the
majority of the residential area is in the vicinity of Morgan and
Spring Street which is located in the southwest corner of the
Study Area. Crittenden Middle School (grades 6-8, approximately
420 students) is also located in the southwest corner of the
Study Area, directly west of the on-site area. The schoolyard is
also used as a public park. There are no hospitals or convales-
cent homes located in the Study Area.
6.4 PRESENCE OF SENSITIVE ECOLOGICAL SYSTEMS
Two endangered species are reported to use South San Francisco
Bay, located approximately 4 miles north of the Study Area. The
California clapper rail and the salt marsh harvest mouse are
reported to exist in the tidal marshes of the Bay and bayshore.
The endangered California brown pelican is occasionally seen in
the Bay Area, but does not nest in the South Bay. Ranges of the
endangered American peregrine falcon and southern bald eagle in-
clude the Bay Area, but these species do not use Bay and bayshore
habitats.
The Study Area does not constitute critical habitat for endan-
gered species nor does it include or impact any "wetlands."
33
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SUMMARY OF AVERAGE-CASE AND MAXIMUM-CASE
CARCINOGENIC AND NONCARCINOGENIC RISKS ASSOCIATED
WITH CURRENT AND HYPOTHETICAL FUTURE LAND-USE CONDITIONS
IN THE STUDY AREA
Lifetime Upper-bound Excess
Cancer Risk
Carcinogenic Risk Average Case Maximum Case
Current Land-Use Condition 5.6 x 10*6 2.0 x 10'5
*
•
Future Land-Use Condition
Shallow Zone 9.4 x 10'5 1.1 x 10'2
Intermediate Zone 1.1 x 10'5 4.3 x 10'*
Hazard Indices
Noncarcinoaenic Risk Average Case Maximum case
Current Land-Use Condition 0.18 0.18
Future Land-Use Condition
Shallow Zone 0.64 16.97
Intermediate Zone 0.51 7.72
TABLE 4: SUMMARY OF CARCINOGENIC AND NON-CARCINOGENIC RISKS
FOR STUDY AREA
-------
I
I
FUTURE HYPOTHETICAL LAND-USE CONDITION:
SUMMARY OF CARCINOGENIC AND NONCARCINOGENIC
RISK AMONG INDICATOR CHEMICALS
SHALLOW ZONE'
CARCINOGENIC RISK
1,1-DCA
1,1-DCE
"PCE
TCE
VC
Total Risk
Lifetime Upperbound Excess
Cancer Risk
Average Case
7.4xlO'7b (0.8)e
S.BxlO"5 (§1.8)
•
8.8X10'7 (0.9)
9.2x10'* (9.8)
2.5xlC'5 (26.1)
9.4X10"5 (100%)
Maximum Case
4.0X10'5 (0.3)
4.2x10'* (3.7)
2.8X10'5 (0.2)
6.5X10'4 (5.8)
l.OxlO'2 (90.0)
1.1X10'2 (100%)
GDI: RfD Ratio
NONCARCINOGENIC RISK
1,1-DCA
1,1-DCE
1,2-DCE
PCE
1,2,4-TCB
1,1,1-TCA
TCE
Toluen«
Total Risk
(Hazard Index)
Average Case
0.0007 (0.1)
0.006 (1.0)
(8.5)
(3.3)
(0.1)
(0.3)
0.05
0.02
0.07
0.002
0.55 (86.7)
0.000002 fO.00031
0.64 (100%)
Maximum Case
0.01 (0.1)
(0.6)
(29.0)
(1.1)
(0.1)
(0.2)
0.10
4.92
0.19
0.001
0.03
11.72 (69.0)
0.00002 fo.0000031
16.97 (100%)
TABLE 5S CHEMICAL SPECIFIC CARCINOGENIC AND NON-CARCINOGENIC
RISKS
-------
SUMMARY OF CARCINOGENIC AND NONCARCINOGENIC
RISK AMONG INDICATOR CHEMICALS
INTERMEDIATE ZONE*
CARCINOGENIC RISK
1,1-DCA
1,1-DCE
PCE
TCE
Total Risk
Lifetime Upper-bound Excess
Cancer Risk
Average Case
2.4X10"7 (2.2)
2.4X10"6 (21.6)
•
5.4X10"7 '(4.8)
7.9X10"* f71.4)
1.1X10"5 (100%)
Maximum Case '«
1.2xlO"6 (0.3)
8.3x10"* (2.0)
9.7x10'* (2.3)
4.1X10'* (95.4^
4.3X10"* (100%)
GDI; RfD Ratio
NONCARCINOGENIC RISK
1,1-DCA
1,1-DCE
1,2-DCE
PCE
1,1,1-TCA
TCE
Total Risk
(Hazard index)
Average Case
0.0002 (0.04)
0.002 (0.4)
(5.4)
(0.3)
0.03
0.001
0.0003
0.48
0.51
(0.1)
(93.81
(100%)
Maximum Case
0.003 (0.04)
0.002
0.30
0.07
0.003
7.35
(0.02)
(3.9)
(0.9)
.(0.04)
(95.1)
7.73 (100%)
* Distribution of risk among indicator chemicals under the assumption
that water from the Shallow Zone is used for domestic purposes.
b Total risk contributed by a chemical via one or more exposure
pathways (water, soil, air) and exposure routes (inhalation,
ingestion).
e Percent of total risk contributed by a chemical.
d Distribution of risk among indicator chemicals under the assumption
that water from the Intermediate Zone is used for domestic —
purposes.
-------
6.5 CONCLUSION
Actual or threatened releases of hazardous substances from the
Teledyne and Spectra-Physics Superfund sites, if not addressed by
implementing the response action selected in this ROD may present
an imminent and substantial endangerment to the public health,
welfare or environment. Based on the fact that a variety of the
VOCs detected in the Study Area pose significant health risks as
carcinogens or as noncarcinogens and complete exposure pathways
exist, EPA has determined that remediation is warranted.
7.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS)
Under Section 121(d)(1) of CERCLA, § 9621, remedial actions must
attain a degree of clean-up which assures protection of human
health and the environment. Additionally, remedial actions that
leave any hazardous substance, pollutant, or contaminant on-site
must meet a level or standard of control that at least attains
standards, requirements, limitations, or criteria that are
"applicable or relevant and appropriate" under the circumstances
of the release. These requirements, known as "ARARs", may be
waived in certain instances, as stated in Section 121(d)(4) of
CERCLA, 42 U.S.C. § 9621(d)(4).
"Applicable" requirements are those clean-up standards, stan-
dards of control and other substantive environmental protection
requirements, criteria, or limitations promulgated under federal
or state law that specifically address a hazardous substance,
pollutant or contaminant, remedial action, location, or other
circumstance at a CERCLA site. "Relevant and appropriate" re-
quirements are clean-up standards, standards of control and other
substantive environmental protection requirements, criteria, or
limitations promulgated under federal or state law that, while
not "applicable" to a hazardous substance, pollutant, con-
taminant, remedial action, location, or other circumstance at a
CERCLA site, address problems or situations sufficiently similar
to those encountered at the CERCLA site that their use is well-
suited to the particular site. For example, requirements may be
relevant and appropriate if they would be "applicable" but for
jurisdictional restrictions associated with the requirement. -See
the National Contingency Plan, 40 C.F.R. Section 300.6, 1986).
The determination of which requirements are "relevant and ap-
propriate" is somewhat flexible. EPA and the State may look to
the type of remedial actions contemplated, the hazardous sub-
stances present, the waste characteristics, the physical charac-
teristics of the site, and other appropriate factors. It is pos-
sible for only part of a requirement to be considered relevant
and appropriate. Additionally, only substantive requirements
need be followed. If no ARAR covers a particular situation, or
if an ARAR is not sufficient to protect human health or the en-
vironment, then non-promulgated standards, criteria, guidance,
and advisories must be used to provide a protective remedy.
37
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7.1 TYPES OF ARABS
There are three types of ARARs. The first type includes
"contaminant specific" requirements. These ARARs set limits on
concentrations of specific hazardous substance, pollutants, and
contaminants in the environment. Examples of this type of ARAR
are ambient water quality criteria and drinking water standards.
The second type of ARAR includes location-specific requirements
that set restrictions on certain types of activities based on
site characteristics. These include restriction on activities in
wetlands, floodplains, and historic sites. The third type of
ARAR includes action-specific requirements. These are
technology-based restrictions which are triggered by the type of
action under consideration. Examples of action-specific ARARs
are Resource Conservation and Recovery Act ("RCRA") regulations
for waste treatment, storage, and disposal.
ARARs must be identified on a site-specific basis from informa-
tion about specific chemicals at the site, specific features of
the site location, and actions that are being considered as
remedies.
7.2 CONTAMINANT-SPECIFIC ARARS
Section 1412 of the Safe Drinking Water Act. 42 U.S.C. Section
300a-l
Under the authority of Section 1412 of the Safe Drinking Water
Act, Maximum Contaminant Levels Goals (MCLGs) that are set at
levels above zero, shall be attained by remedial actions for
ground or surface water that are current or potential sources of
drinking water, where the MCLGs are relevant and appropriate un-
der the circumstances of the release based on the factors in
§300.400 (g)(2).
The appropriate remedial goal for each indicator chemical (except
toluene and 1,2,4-TCB) in ground water is the MCLG (if not equal
to zero), the federal MCL, or the State MCL, whichever is most
stringent. The MCLGs and MCLs for the indicator chemicals iden-
tified in the Study Area are given in Table 6 .
California Deptartment of Health Services Drinking Water Action
Levels (DWALS)
California Department of Health Services (DHS) DWALs are health-
based concentration limits set by the DHS to limit public ex-
posure to substances not yet regulated by promulgated standards.
They are advisory standards that apply at the tap for public
water supplies. The DWAL for toluene is 100 ppb.
California's Resolution 68-16
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California's "Statement of Policy With Respect to Maintaining
High Quality of Waters in California," Resolution 68-16, affects
remedial standards. The policy requires maintenance of existing
water quality unless it is demonstrated that a change will
benefit the people of the State, will not unreasonably affect
present or potential uses, and will not result in water quality
less that prescribed by other State policies.
State of California Soluble Threshold Limit Concentrations (STLC)
and Total Threshold Limit Concentrations (TTLC)
The State of California Soluble Threshold Limit Concentrations
(STLC) and-Total Threshold Limit Concentrations (TTLC) are ap-
plicable as the means of determining whether soils that are ex-
cavated consitute a hazardous waste. Of the nine indicator
chemicals, only TCE has a STLC and TTLC values. The STLC for TCE
is 204 ppm; the TTLC for TCE is 2,040 ppm. Levels of TCE
detected in the Study Area exceed these levels.
7.3 ACTION SPECIFIC ARARS AND TBCS
National Pollutant Discharge Elimination System (NPDES)
NPDES substantive permit requirements and/or RWQCB Waste Dis-
charge Requirements (WDRs) are potential ARARs for effluent dis-
charges. The effluent limitations and monitoring requirements of
an NPDES permit/WDRs legally apply to point source discharges
such as those from a treatment system with an outfall to surface
water or storm drains. The RWQCB establishe effluent discharge
limitations and permit requirements based on Water Quality Stan-
dards set forth in the San Francisco Bay Regional Basin Plan.
City of Mountain View Industrial Waste Ordinance and the Federal
Clean Water Act Pretreatment Standards (40 CFR 403.5)
Substantive requirements of the City of Mountain View Industrial
Waste Ordinance and the Federal Clean Water Act Pretreatment
Standards (40 CFR 403.5) are ARARs for discharges of ground water
to the local sanitary sewer system. The Clean Water Act allows
municipalities to determine the pretreatment standards for dis-
charges to Publicly Owned Treatment Works (POTWs) within its •
jurisdiction.
EPA Office of Solid Waste and Emergency Response (OSWER) Direc-
tive 9355.0-28
OSWER Directive 9355.0-28 "Control of Air Emissions from Super-
fund Groundwater Air Strippers at Superfund Groundwater Sites"
applies to future remedial decisions at Superfund sites in ozone
non-attainment areas. Future remedial decisions include Records
of Decisions (RODs), Significant Differences to a ROD and Consent
Decrees. Teledyne and Spectra-Physics are in what is considered
an ozone non-attainment area. This directive requires such sites
to control total volatile organic compound emissions from air
39
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CLEANUP LEVELS FOR GROUND WATER
Chemical
1,1-DCA
1,2-DCB
1,1-DCE
1,2-DCE
PCE
1,2,4-TCB
1,1,1-TCA
1,1,2-TCA
TCE
Toluene
vc
Chloroform
U.S. EPA
MCLG
(PPb)
—
600
7
70U)
0
9
200
3
0
1000
0
—
U.S. EPA
MCL
(Ppb)
—
600
7
70(D
5
9
200
5
5
1000
2
100
California
MCL
(Ppb)
5
• —
6
sd)
5
—
200
32
5
100<2>
0.5
—
(1) MCL for cis-l,2-DCE
(2) DHS action level
TABLE 6: CHEMICAL SPECIFIC ARARS
40
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strippers and soil vapor extractors to fifteen pounds per day per
facility. This directive is what is called a "To Be Considered"
or TBC. ARARs with more stringent requirements take precedence
over the directive.
Bay Area Air Quality Management District (BAAOMD) Regulation 8.
Rule 47
Bay Area Air Quality Management District Board of Directors
adopted Regulation 8, Rule 47; "Air Stripping and Soil Vapor Ex-
traction Operations" which applies to new and modified opera-
tions. Tha rule consists of two standards:
o Individual air stripping and soil vapor extraction opera-
tions emitting benzene, vinyl chloride, perchloroethylene,
methylene chloride and/or trichloroethylene are required to
control emissions by at least ninety percent by weight.
- Operations emitting less than one pound per day of these
compounds are exempt from this requirement if they pass a
District risk screen.
o Individual air stripping and soil vapor extraction opera-
tions emitting greater than fifteen pounds per day of or-
ganic compounds other than those listed above are required
to control emissions by at least ninety percent by weight.
Regulation 8, Rule 47 is an ARAR for the implementation of the
remedy in the Study Area.
Resource Conservation Recovery Act (RCRA1 Land Disposal
Restrictions
Adsorbents and other materials used for remediation of VOCs, such
as activated carbon, chemical-adsorbing resins, or other
materials used in the treatment of ground water or air will con-
tain the chemicals after use. RCRA land disposal restrictions
are not applicable but are relevant and appropriate to disposal
of treatment media due to the presence of constituents which are
sufficiently similar to RCRA wastes.
7.4 LOCATION-SPECIFIC ARARS
Fish and Wildlife Coordination Act
The Fish and Wildlife Coordination Act is an applicable require-
ment for the locations adjacent to Permanente Creek and other
tributary streams and marshes.
8.0 DESCRIPTION OF ALTERNATIVES
Feasibility studies were prepared for the three geographic areas
distinguished within the Study Area. The three geographic areas
are as follows:
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o The Teledyne Semiconductor "On-Site" area which is defined
as the area within the property boundaries of Teledyne Semi-
conductor;
o The Spectra-Physics, Inc., "On-Site" area which is defined
as the area within the property boundaries of Spectra-
Physics, Inc.;
o The Teledyne Semiconductor and Spectra-Physics, Inc. "Off-
Site" area, which is defined as the area outside the
property boundaries of the two companies and within the
boundaries of the plume.
Please note that the terms "on-site" and "off-site" do not per-
tain to the boundaries of the Superfund site and therefore are
not consistent with the definitions given in the March 8, 1990
National Contingency Plan.
The" remediation alternatives evaluated for the Study Area are
listed and described herein according to the geophraphical areas
described above with the exception of the "No Action" alterna-
tive.
Alternative 1 - No Action
The no action alternative was considered for each of the
geographical areas as a baseline to compare remedial alterna-
tives. Under the No Action alternative, the existing groundwater
and soil vapor extraction and treatment systems would be removed.
Groundwater monitoring would continue.
8.1 TELEDYNE SEMICONDUCTOR ON-SITE AREA
Alternative 2 - Existing Groundwater Extraction System
Contaminated ground water with contaminant concentrations in ex-
cess of cleanup standards is extracted from the Shallow and In-
termediate zones of the Upper Aquifer using the existing extrac-
tion wells. The extracted water would continue to be discharged
under permit to the sanitary sewer for treatment at the POTW.
Alternative 3 - Existing Groundwater Extraction System with Air
Stripping
Ground water from the Shallow and Intermediate Zones would be
pumped out using existing extraction wells. The water would then
be treated to the cleanup levels listed in Table 6 by an air
stripping system that uses a packed bed tower. The treated ef-
fluent would be discharged to the storm drain under NPDES permit.
The air emitted from the stripper would require subsequent treat-
ment by carbon adsorption to meet local air emission require-
ments .
42
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Alternative 4 - Existing Groundwater Extraction System with
Carbon Adsorption
Ground water from the Shallow and Intermediate Zones would be
pumped out using existing extraction wells and the water would be
treated the cleanup levels listed in Table 6 with activated car-
bon. The activated carbon would consist of two packed bed reac-
tors operating in a downflow series mode. One reactor could
operate while the carbon in the other reactor is being replaced
with regenerated carbon. The treated effluent would be dis-
charged to the storm drain under NPDES permit.
Alternative' 5 - Existing Groundwater Extraction System and Treat-
ment to Background Levels
The existing groundwater extraction system would be expanded to
capture ground water with VOC concentrations in excess of back-
ground concentrations from the Shallow and Intermediate Zones»
The extracted groundwater would be treated by carbon adsorption
or air stripping until the concentrations of chemicals remaining
in the ground water are reduced to background levels. The
treated effluent would be discharged to the storm drain under
NPDES permit.
8.2 SPECTRA-PHYSICS INC., ON-SITE AREA
Alternative 2 - Institutional Actions
The existing soil-vapor extraction and treatment systems would be
shut down and several institutional actions would be implemented.
This alternative restricts the future excavation of VOC-affected
soils through zoning and/or building permit restrictions, and
precludes the future extraction of Upper Aquifer ground water
through Santa Clara Valley Water District regulations.
Alternative 3 - Soil Excavation with Existing_Groundwater
Extraction
Soils containing TCE above 2.5 ppm at the facility would be
selected for excavation and disposal at a RCRA-permitted
landfill. The Teledyne Semiconductor groundwater extraction sys-
tem would continue to operate to capture and treat ground water
from the Shallow and Intermediate Zones of the Upper Aquifer.
Extracted ground water will be treated to the levels listed in
Table 6 by either an air stripper or granular activated carbon
followed by discharged to the storm drain under NPDES permit.
Alternative 4 - Expansion of Existing Soil Vapor Extraction and
Continued Operation of Existing Groundwater
Extraction System
The existing soil-vapor extraction and treatment system would be
expanded to include additional areas where soil contains TCE in
excess of 2.5 ppm. The Teledyne Semiconductor groundwater ex-
43
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traction system would continue to operate to capture and treat
iground water from the Shallow and Intermediate Zones of the Upper
Aquifer. Extracted ground water will be treated to the levels
listed in Table 6 by either an air stripper or granular activated
carbon followed by discharged to the storm drain under NPDES per-
mit.
Alternative 5 - Expansion of Existing Soil Vapor Extraction and
Additional Groundwater Extraction
The existing soil-vapor extraction and treatment system would be
expanded the same as Alternative 4 and two Shallow zone
groundwater extraction wells would be installed at the Spectra-
Physics facility. Extracted ground water will be treated to the
levels listed in Table 6 by either an air stripper or granular
activated carbon followed by discharge to the storm drain under
NPDES permit.
Alternative 6 - Expansion of Existing Soil Vapor Extraction and
Continued Operation of Existing Groundwater
System to Achieve Background Levels in Ground
The existing soil-vapor extraction and treatment system would be
expanded to include additional areas where soil contains TCE in
excess of 2.5 ppm. Ground water would continue to be extracted
by the Teledyne Semiconductor system until concentrations of
chemicals remaining the Upper Aquifer are reduced to background
levels. Extracted ground water will either be treated by an air
stripper or granular activated carbon followed by discharged to
the storm drain under NPDES permit.
8.3 TELEDYNE SEMICONDUCTOR AND SPECTRA-PHYSICS OFF-SITE AREA
Alternative 2 - Institutional Actions
Existing extraction wells, Spring Street Extraction System (SSES)
and North Bayshore Extraction System (NBES), would be abandoned
and the Santa Clara Valley Water District would institute
restrictions preventing the development of the Upper Aquifer.
This alternative involves the use of alternate water supplies to
Upper Aquifer wells (including wellhead treatment where
necessary), a well permit restriction, and the use of ground-
water monitoring to document changes in the concentration or area
in which ground water contains VOCs.
Alternative 3 - Existing Groundwater Extraction System
The Spring Street Extraction System (SSES) and North Bayshore Ex-
traction (NBES) will continue to extract ground water in the
Shallow Zone and Intermediate Zones of the Upper Aquifer. For
this alternative, removal of ground water containing contaminants
in excess of the levels listed in Table 6 is the objective.
44
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After capture, the ground water would require treatment and dis-
posal. The treatment and discharge subalternatives for Alterna-
tive 3 as well as Alternatives 4, 5, and 6 are as follows:
A. Discharge to the sanitary sewer and treatment by Publicly
Owned Treatment Works (POTW);
B. Treatment by air stripping with air emission controls and
discharge to the storm drain under NPDES permit. Air
emission controls considered are:
o granular activated carbon vapor controls, or
o co-combustion of vapors with the City of Mountain View
Landfill flares;
C. Treatment by aqueous phase granular activated carbon
treatment and discharge to the storm drain under NPDES
- permit;
D. Treatment by photolysis and oxidation and discharge to
storm drain under NPDES permit.
Alternative 4 - Limited Existing Groundwater Extraction System
The SSES and the NBES would discontinue using four of the exist-
ing extraction wells and the combined captured zone for the Study
Area would be reduced. Shallow and Intermediate ground water
with TCE concentrations greater than 100 ppb would be captured.
Alternative 5 - Expansion of Existing Groundwater Extraction
System
The SSES and the NBES would be expanded by seven additional wells
to achieve a larger capture zone in the Study Area. Shallow and
Intermediate Zone ground water with VOC concentrations above
background levels would be extracted.
Alternative 6 - Existing Groundwater Extraction System and
In-jection
Alternative 3 would be employed and treated water would be in-
jected back into the subsurface via injection wells located
lateral to and downgradient of the affected areas. The injection
would provide a hydraulic barrier to prevent further spread of
the polluted water.
9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
This section provides an explaination of the criteria used to
select the remedy, and an analysis of the remedial action alter-
natives in light of those criteria, highlighting the advantages
and disadvantages of each of the alternatives.
45
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Criteria
The alternatives were evaluated using nine component criteria.
These criteria, which are listed below, are derived from require-
ments contained in the National Contingency Plan (NCP) and CERCLA
Sections 121(b) and 121(c).
1. Overall protection of human health and the
environment.
2. Short term effectiveness in protecting human
health and the environment.
3. Long-term effectiveness and permanence in
protecting human health and the environment-.
4. Compliance with ARARs (ARARs are detailed in Section
7.0).
5. Use of treatment to achieve a reduction in the
toxicity,mobility or volume of the contaminants.
6. Implementability.
7. State acceptance/Support Agency acceptance.
8. Community acceptance.
9. Cost.
9.1 TELEDYNE SEMICONDUCTOR ON-SITE AREA
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The contamination within the boundaries of the Teledyne Semicon-
ductor On-Site Area is principally groundwater contamination in
the Upper Aquifer unit. The groundwater contamination within the
boundaries of the Teledyne Semiconductor On-Site Area represents
a portion of the defined plume area (Figures 8 and 9).
Alternative 2 provides protection of human health and the en-
vironment by reducing the volume of contamination in the Shallow
and Intermediate zones of the Upper Aquifer and thereby reducing
all risks associated with the presence of VOCs in the ground
water. The potential for human exposure to the chemical-
containing water still exists via volatilization from sanitary
sewer manholes. However, this risk was determined to be within
EPA's target risk range. The calculated health risk after the
remedial objectives are achieved are estimated to range from 1.6
x 10"6 to 2.7 x 10~5 for carcinogenic risk with a hazard index of
less than 1.0.
46
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Alternative 3 provides protection of human health and the en-
vironment in the same way as Alternative 2 and also eliminates
the risks associated with discharging to the sanitary sewer by
including treatment with an air stripper prior to discharging.
The BAAQMD will determine if air emission controls are required.
The calculated health risks after the remedial objectives are
achieved are the same as Alternative 2.
Alternative 4 also provides protection of human health and the
environment in the same way as Alternative 2 and also eliminates
the risks associated with discharging to the sanitary sewer by
including treatment of extracted water with carbon adsorption
prior to discharging. The calculated health risks after the
remedial objectives are achieved are the same as Alternative 2.
Alternative 5 also provides protection of human health and the
environment in the same way as Alternative 2 and also eliminates
the -risks associated with discharging to the sanitary sewer by
including treatment with either carbon adsorption or air strip-
ping prior to discharging. This alternative is designed to ex-
tract ground water from the Upper Aquifer containing VOCs in ex-
cess of background levels. The calculated health risks after the
remedial objectives are achieved are the same as Alternative 2.
The No Action Alternative would provide no protectiveness or risk
reduction. The average CRI for the Shallow Zone range from 9.4 x
10~5 to 1.1 x 10~2 and the HI would range from 0.64 to 16.97,
respectively.
COMPLIANCE WITH ARAR5
The ARARs pertinent to Alternatives 2-5 are set forth in Sec-
tion 7 of this report. All ARARs would be attained by Alterna-
tives 2-5. The No Action alternative would not attain all
ARARs or provide grounds for a waiver.
REDUCTION OF TOXICITY. MOBILITY. OR VOLUME THROUGH
TREATMENT
Alternatives 2-5 will reduce the concentration of VOCs in the
Upper Aquifer by extracting contaminated ground water from the
aquifer thereby reducing the volume of contamination. Toxicity
associated with the presence of VOCs in the Upper Aquifer will
also be reduced through the extraction of contaminated ground
water from the Upper Aquifer.
Alternative 2 does not provide any treatment other than the
volatilization and degradation of VOCs at the POTW. This treat-
ment does not provide complete destruction of chlorinated
hydrocarbons.
Alternatives 3, 4, and 5 provide destruction of VOCs by incinera-
tion of spent carbon which reduces VOCs to CO2.
47
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The No Action altemtive does not provide either reduction of
toxicity, mobility, or volume through treatment.
LONG-TERM EFFECTIVENESS AND PERMANENCE
Alternatives 2-5 include groundwater extraction which is in-
tended to reduce the level of contamination in the Upper Aquifer
below action levels for the contaminants described in Section
6.0. Thus, potential risks to the community currently posed by
the site in its present condition are minimized. To ensure that
the magnitude of residual risks are minimized, the performance of
the groundwater extraction system will be carefully monitored on
a regular basis and adjusted as warranted by the performance data
collected during operation. Modifications may include:
a) discontinuing operation of extraction wells in areas
where cleanup standards have been attained;
b) Alternating pumping at wells to eliminate stagnation
points;
c) pulse pumping to allow aquifer equilibration and
encourage adsorbed contaminants to partition into
ground water;
d) installation of additional extraction wells.
Treatment by POTW provided by Alternative 2 is reliable for the
complete or near-complete removal of VOCs from the extracted
ground water. Treatment residuals are expected to be low, based
on the high volatility of the VOCs. The hypothetical health risk
is not affected by the treatment alternative.
Treatment by air stripping provided by Alternatives 3 and 5 is
reliable for the long-term removal of VOCs from the ground water.
Treatment residuals are expected to be negligible based on the
high volatility of the compounds present in the ground water.
Treatment by aqueous phase granular activated carbon provided by
Alternatives 4 and 5 is reliable for the removal of VOCs from the
ground water. Treatment residuals are expected to be negligible
based on the high volatility of the compounds present in the
ground water.
The No Action alternative provides no long term effectiveness.
SHORT-TERM EFFECTIVENESS
The short-term impact to the health of workers and community will
be very minimal for Alternatives 2-5 because the groundwater
extraction system is already in place at the site. Alternative 2
includes a risk associated with the volatilization of VOCs at the
point of discharge to sanitary sewer. This risk, however, was
determined to be within the 10~4 to 10"~6 carcinogenic risk range
48
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and the hazard index is less than 1.0. Alternatives 3 and 5
would employ an air stripper which would emit VOCs into the air.
However, emissions from air stripping towers will be controlled
to meet local air district requirements.
The No Action Alternative does not include the implementation of
any remedial action, therefore, there are no risks associated
with the implementation of a remedy. The risks associated with
the contamination of the Upper Aquifer would remain at the site.
IMPLEMENTABILITY
Alternatives 2-5 include the same extraction system which is
already in place. Alternatives 3, 4 and 5 provide groundwater
treatment with either an air stripper or with carbon adsorption.
Both methods are proven technologies and there are no technical
considerations that prohibit the use of either of these tech-
nologies.
There are no technical concerns regarding the implementability of
the no action alternative.
COST
The capital cost for Alternative 2 (installation of extraction
wells RA1 in 1896 and T32I in 1989) is $58,775 in 1991 dollars
with 5% annual inflation rate. Operation and maintenance costs
associated with monitoring and sewer disposal fees are estimated
to be approximately $105,000/year and the present worth is es-
timated to be $2,066,725 for a nominal 30-year period using 5
percent interest rate.
The capital cost for Alternative 3 is $248,775, with an operation
and maintenance cost of $86,000 per year. The present worth of
this alternative is estimated to be $2,000,000 for a nominal 30-
year period using 5 percent interest rate.
The capital costs for Alternative 4 is $144,000, with an opera-
tion and maintenance cost of $80,000 per year. The present worth
cost is estimated to be $1,777,000 for a nominal 30-year period
using a 5 percent interest rate.
The capital cost for Alternative 5 would be the same as either
Alternative 2, 3 or 4, depending on the selected treatment
method. The operation and maintenance would also be consistent
with either Alternative 2, 3 or 4, depending on the selected
treatment method, therefore, the nominal 30 year present worth
will remain the same for each option.
SUPPORT AGENCY ACCEPTANCE
The Feasibility Study and the Proposed Plan Fact Sheet were
reviewed by California Regional Water Quality Control Board
(RWQCB). The RWQCB concurs with EPA's preferred alternative.
49
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COMMUNITY ACCEPTANCE
The Proposed Plan was presented to the community of Mountain View
in a fact sheet and at a public meeting. No technical comments
were submitted regarding the alternatives. Other comments
received are addressed in the Response Summary.
THE SELECTED REMEDY
The selected remedy for the Teledyne on-site area is Alternative
3. Alternative 3 consists of continuing the current groundwater
extraction.system to capture ground water containing contaminants
in excess of the levels listed in Table 6, treating the extracted
water with an air stripper. The air stripper will be equipped
with vapor phase GAG treatment if required by BAAQMD and/or EPA
OSWER Directive 9355.0-28. Treated water will be discharged un-
der NPDES permit to the storm drain.
Alternative 3 measures evenly against Alternatives 2, 4, and 5
for all of the criteria. The principal advantages of Alternative
3 are that it provides groundwater treatment so water may be con-
sidered for reuse at a future date.
9.2 SPECTRA-PHYSICS ON-SITE AREA
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The Spectra-Physics On-Site area represents a portion of the
defined VOC plume in the Upper Aquifer and all of the soil con-
tamination known to remain within the boundaries of the Study
Area.
Alternative 2 does not reduce nor eliminate the risks associated
with contamination of the Upper Aquifer or contamination of the
soils. This alternative does not offer any reduction of risk
levels so the CRI for the Shallow Zone will range from 9.4 x 10
to l.l x 10~2 and the HI will range from 0.64 to 16.97.
Alternative 3 provides for excavation of soil that contains TCE
above concentrations of 2.5 ppm and continuing groundwater ex-
traction from the wells located at the Teledyne Semiconductor
facility. Evaluation of the extraction system at the Teledyne
facility is provided in Section 9.1. Removal of VOC-affected
soils from the site reduces the total quantity of VOCs present by
transferring the material to a Class I landfill. This alterna-
tive would provide overall protection of human health and the en-
vironment in the long term. However, Alternative 3 may create a
greater risk by exposing workers and residents to large volumes
of contaminated soils during the period of excavation.
Alternative 4 includes expansion of the the existing soil vapor
extraction system for soil remediation and operation of the
Teledyne On-Site extraction system for groundwater remediation.
The soil vapor extraction system would be designed to remediate
50
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VOCs in the upper ten feet of soils in excess of 2.5 ppm TCE and
soils in excess of 0.5 ppm TCE below ten feet. This alternative
will reduce the volume of VOCs in the soils and reduce the risks
associated with contaminants leaching out of the soils into the
ground water. Emissions from the soil vapor extraction system
are required to achieve standards enforced by the BAAQMD. The
groundwater extraction system discussed in Section 9.1 would
provide remediation for contaminated ground water emanating from
the Spectra-Physics On-Site area. This alternative would reduce
the level of contamination in the Upper Aquifer and in the soils,
thus reducing the risks associated with the presence of con-
tamination. Therefore, this alternative provides overall protec-
tion to human health and the environment.
Alternative 5 provides soil remediation using the same soil vapor
extraction system described for Alternative 4. Groundwater
remediation is enhanced by installing two Shallow Zone extraction
wells at the Spectra-Physics On-Site area. These groundwater
wells would be installed and operated in addition to wells
presently operating at the Teledyne Semiconductor On-Site area.
This alternative would enhance groundwater remediation by ensur-
ing that contamination emanating from Spectra-Physics is captured
within a smaller area. Based on the discussion of Alternative 4,
it is determined that Alternative 5 provides overall protection
of human health and the environment.
Alternative 6 provides for soil and ground water remediation
similar to Alternative 4. However, Alternative 6 requires that
VOC levels in the ground water are reduced to background levels
(essentially non-detectable). Based on the discussion of Alter-
native 4, it is determined that Alternative 6 provides overall
protection of human health and the environment.
The No Action alternative does not provide overall protection of
human health and the environment.
COMPLIANCE WITH ARARS
Alternative 2 does not include any type of soil or ground water
remediation. Therefore, contamination is affected only by
natural processes and ARARs are not achieved.
Alternative 3 includes groundwater extraction and soil excava-
tion. Soil excavation is subject to a number of ARARs which have
been identified in Section 7. Groundwater extraction is intended
to capture contaminants in excess of the respective action levels
listed in Table 6. This alternative would comply with ARARs.
Alternative 4 includes groundwater extraction and soil vapor ex-
traction. Soil vapor extraction is subject to a number of ARARs
which have all been identified in Section 7. Groundwater extrac-
tion is intended to capture indicator chemicals in excess of the
respective action levels listed in Table 6. This alternative
would comply with ARARs.
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Alternatives 5 and 6 are expected to comply with ARARs based on
the evaluation provided for Alternatives 3 and 4.
The No Action alternative does not comply with ARARs.
REDUCTION OF TOXICITY. MOBILITY. OR VOLUME THROUGH TREATMENT
Alternative 2 provides no type of groundwater or soil treatment.
Therefore, this criterion is not achieved.
Alternative 3 will reduce the total quantity of VOCs at the On-
Site area by excavating VOC-contaminated soils and transferring
the material to a Class I landfill. Landfilling the material
does not provide any reduction of toxicity, mobility., or volume
through treatment of the VOCs. Alternative 3 provides groundwater
remediation through the operation of the groundwater extraction
wells at the Teledyne On-Site Area. The groundwater system and
the-treatment options all provide reduction of toxicity,
mobility, or volume through treatment.
Alternatives 4, 5, and 6 provide soil treatment by expanding the
existing soil vapor extraction system. Soil vapor extraction of
soils affected by 2.5 ppm or more TCE effectively reduces the
volume of VOCs in soils. The captured VOCs are adsorbed to ac-
tivated carbon and thermal regeneration of carbon will provide
permanent destruction of VOCs. In conclusion, soil remediation
for Alternatives 4, 5, and 6 will provide reduction of toxicity,
mobility, or volume through treatment.
Alternatives 4 and 6 depend on the Teledyne On-Site extraction
wells for ground water remediation. The groundwater system and
the treatment options all provide reduction of toxicity,
mobility, or volume through treatment.
Alternative 5 provides groundwater remediation with the operation
of the Teledyne On-Site extraction wells and the addition of two
Shallow Zone extraction wells installed at the Spectra-Physics
On-Site area. This system has the potential to reduce near
source VOC concentrations in the Shallow Zone to action levels.
However, it has not been determined if whether VOC concentrations
in the Shallow Zone will be reduced quicker by operating extrac-
tion systems on both the Teledyne and Spectra-Physics On-Site
areas compared to operating only the Teledyne On-Site system. .
This would be the only added benefit of installing the additional
extraction wells. This alternative does provide reduction of
toxicity, mobility, or volume through treatment.
The No Action alternative does not provide reduction of toxicity,
mobility, or volume through treatment.
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LONG-TERM EFFECTIVENESS AND PERMANENCE
Alternative 2 provides no effective measure for remediating
groundwater and soil contamination. Therefore, risks associated
with the presence of this contamination remain unaffected. Al-
ternative 2 includes the monitoring of untreated soil and ground
water contamination. Alternative 2 does not provide long-term
effectiveness or permanence.
Alternative 3 provides soil remediation by excavation. Soil
removal has the long-term benefit for the Site of removing soils
containing VOCs, thus reducing the risks associated with the
presence of contamination in the soil. However, because no VOCs
are destroyed by treatment, this is not a permanent remedy for
VOC-containing soils. The transfer process increases the pos-
sibilty of exposure due to loss in transit, and future releases
at the disposal site. With this alternative, the long-term
health risks associated with soils are carcinogenic risk of 1.7 x
10~7 and a hazard index of 7.4 x 10~ .
Alternatives 4, 5, and 6 would provide soil remediation by ex-
panding the existing soil vapor extraction system to remediate
soils containing TCE in excess of 2.5 ppm in the upper 10 feet
and 0.5 ppm below 10 feet. Soil vapor extraction removes the
threat of migration or exposure to VOCs in soil. Existing pave-
ment overlying the site area will limit the migration of any
residual soil contamination. Soil vapor extraction provides a
long-term effective and permanent remedy for soil contamination.
By expanding the soil vapor extraction system, the long-term
health risks are the same as with Alternative 3.
Alternatives 3, 4, and 6 provide groundwater remediation with the
groundwater extraction system operating at the Teledyne On-Site
area. The groundwater extraction and treatment systems con-
sidered for the Teledyne On-Site area are evaluated in Section
9.1.
Alternative 5 enhances groundwater remediation by adding two ad-
ditional Shallow Zone extraction wells at the Spectra-Physics
On-Site area which will operate in conjuction with the extraction
wells at the Teledyne On-Site Area. The objective of this com-
ponent of Alternative 5 is to reduce the levels of VOCs in the
Upper Aquifer to or below action levels. Theoretically, this al-
ternative will achieve chemical specific ARARs in a shorter
period of time. However, the long-term health risks associated
with the groundwater extraction for this alternative are the same
as Alternatives 3, 4, and 6.
The No-Action alternative would result in residual soil and
ground water contamination which may create greater risks as the
contaminants migrate. The No-Action alternative does not provide
long-term effectiveness or permanence.
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SHORT-TERM EFFECTIVENESS
Alternative 2 does not increase risk to residents or workers as a
result of implementing the remedy. Since Alternative 2 provides
no effective measure for remediating groundwater and soil con-
tamination, all risks associated with the presence of this con-
tamination remain unaffected.
Alternative 3 includes excavation which is expedient but also
creates the greatest short term potential for adverse human
health effects to field personnel, site employees, or nearby
residents due to exposure from chemicals in soil during excava-
tion, loading, or transportation. Based on the risks associated
with soil excavation, Alternative 3 may increase short-term
risks.
Alternatives 4, 5, and 6 include enhancing soil remediation by
expanding the existing soil vapor extraction system. Potential,
short-term risks associated with expanding the soil vapor extrac-
tion system includes exposure to contaminated soil from drilling
or trenching, handling excavated material, and any fugitive emis-
sions resulting from the soil vapor extraction system. All of
these risks are expected to be minimal and the short-term risk
levels are not expected to increase as a result of the installa-
tion and operation of the soil vapor extraction system.
Alternatives 3, 4, and 6 provide groundwater remediation with the
operation of the Teledyne On-Site area groundwater extraction and
treatment system. Short term risks associated with groundwater
extraction and treatment systems considered for the Teledyne On-
Site area are evaluated in Section 9.1.
Alternative 5 includes the addition of two On-Site, Shallow Zone
extraction wells to enhance groundwater remediation. Short-term
exposure associated with installation of groundwater extraction
systems include exposure of workers or residents to soils and
ground water produced in the drilling operations. These poten-
tial exposures are fairly minimal and can be easily controlled.
The No Action alternative provides no effective measures for
remediating groundwater and soil contamination. Therefore,
risks associated with the presence of this contamination remain
unaffected. Alternative 2 does not provide short-term effective-
ness.
IMPLEMENTABILITY
Alternative 2 is an institutional program which may be imple-
mented. There is no type of construction associated with this
alternative.
Alternative 3 may be difficult to implement. It is not known if
owners and occupants of properties adjacent to selected loca-
tions would grant the access needed for excavation, staging of
54
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equipment and- stockpiling soils. The 0.37-acre area to be ex-
cavated is currently covered with pavement which would have to be
removed before excavating. There is limited space available for
the operation of heavy equipment. For these reasons, Alternative
3 would be difficult to implement. The groundwater extraction
system for Alternative 3 is already implemented.
Alternatives 4 thru 6 are all partially implemented and the con-
struction of additional soil vapor extraction wells and/or
groundwater extraction wells is reliable and easily implemented.
The No-Action alternative is implementable.
COST
As a basis for comparison, the cost figures provided" for Alterna-
tives 3 thru 6 assumes that the groundwater extraction systems
included for each of these alternatives will be discharging under
permit to the sanitary sewer for treatment at the POTW.
For Alternative 2, the capital cost is approximately $180,960;
the annual operation and maintenance cost is $53,160; and the'
present worth is $794,811.
For Alternative 3, the capital cost is approximately $4,495,525;
the annual operation and maintenance costs are approximately
$158,160; and the present worth is approximately $6,723,538.
For Alternative 4, the capital cost is approximately $480,621;
the annual operation and maintenance costs are approximately
$188,600, and the present worth is approximately $2,729,595.
For Alternative 5, the capital cost is approximately $752,271;
the annual operation and maintenance costs are approximately
$310,956; and the present worth cost is approximately $4,882,162.
For Alternative 6, the capital cost is $427,871; the annual
operation and maintenance costs are approximately $188,600, and
the present worth cost is approximately $2,676,845.
SUPPORT AGENCY ACCEPTANCE
The Feasibility Study and the Proposed Plan Fact Sheet were
reviewed by California Regional Water Quality Control Board
(RWQCB). The RWQCB concurs with EPA's preferred alternative.
COMMUNITY ACCEPTANCE
The Proposed Plan was presented to the community of Mountain View
in a fact sheet and at a public meeting. No technical comments
were submitted regarding the alternatives. Other comments
received are addressed in the Response Summary.
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THE SELECTED REMEDY
Alternative 4 is the selected remedial alternative for the
Spectra-Physics site. Alternative 4 consists of expanding the
soil vapor extraction system and employing the Teledyne On-Site
groundwater extraction and treatment system to provide ground-
water remediation of the Spectra-Physics On-Site area. The ex-
isting soil vapor extraction system of three soil vapor extrac-
tion wells at the southeast corner of Building 3 will be expanded
to include soil vapor extraction in four additional areas; the
northeast and northwest corners of Building 3 and the east and
west sides of Building 2 (Figure 7). Emissions from soil vapor
extraction system are to be controlled with granular activated
carbon.
Alternative 4 is protective of human health and the environment.
Groundwater contamination is treated so that the remaining poten-
tial- future risks fall within the 10"4 to 10~6 carcinogenic risk
range for acceptable cleanup levels. The remedy complies with
ARARs by achieving cleanup federal and State MCLs or RDWALs.
Soil is remediated to a level that will protect ground water from
future solvent contamination. The remedy is effective in the
short-term and in the long-term by virtue of the fact that ARARs
are achieved. Alternative 4 provides active, immediate, short-
term and long-term reduction of toxicity, mobility, and volume of
chemicals in soils and ground water. Alternative 4 is easy to
implement, it is accepted by the community of Mountain View and
the RWQCB, and is cost effective. Alternative 5 would accelerate
On-Site groundwater remediation, however, it is not guaranteed to
accelerate the overall remediation of the Study Area. Therefore,
Alternative 4 is the selected remedy.
9.3 TELEDYNE SEMICONDUCTOR/SPECTRA-PHYSICS OFF-SITE AREA
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
Alternative 2 provides institutional restrictions preventing the
extraction of ground water from Upper Aquifer (minimum depth of
100 feet) in the Study Area. This alternative does not provide
any sort of remediation to the Upper Aquifer which would
eliminate the future and present, human health and environmental
risks associated with the presence of contamination in the Upper
Aquifer.
Alternatives 3 and 5 will afford protection to human health and
the environment by removing VOCs from the Upper Aquifer through
extraction and subsequent treatment and discharge. In addition
to removing VOCs from the Upper Aquifer, all of these alterna-
tives will increase the upward hydraulic gradient between the Up-
per and Deep Aquifers, thus reducing the risk of downward VOC
migration. The risks associated with the operation of the
respective treatment methods for each alternative are regulated
by ARARs identified in Section 7 and are not expected to exceed
acceptable risk levels.
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Alternative 4 also affords protection to human health and
the environment by removing VOCs from the Upper Aquifer.
However, this alternative is intended to capture ground water
with concentrations of TCE greater than 100 ppb. This will
reduce the current level of contamination in the Upper Aquifer as
well as reduce the risk of downward migration, however, ARARs for
protection of ground water as a drinking water source are not
achieved.
Alternative 6 affords protection to human health and the environ-
ment by removing VOCs from the Upper Aquifer to the levels listed
in Table 6. Following extraction and treatment, part of the ef-
fluent would be reinjected into the Upper Aquifer to possibly
enhance recovery of VOCs. This action may result in-spreading
contaminants into unaffected areas as well as create a downward
gradient into the Deep Aquifer. Because there are potential
risks associated with Alternative 6, this alternative is con-
sidered less protective of human health and the environment than
Alternatives 3 and 5.
Treatment and disposal subalternatives for Alternatives 3,4, 5,
and 6 do not affect how these alternatives are evaluated accord-
ing to overall protection of human health and the environment.
The No Action alternative does not afford any protection to human
health and the environment.
COMPLIANCE WITH ARARS
Alternative 2 does not provide any sort of remediation for the
Upper Aquifer. Therefore, cleanup levels are not acheived. This
alternative does not comply with chemical specific ARARs.
Alternatives 3, 4, and 6 would provide extraction of ground water
containing indicator chemicals at concentrations greater than the
resepective cleanup levels. Therefore, Alternatives 3, 4, and 6
comply with chemical specific ARARs.
Alternative 5 does not extract ground water containing indicator
chemicals at concentrations greater than the respective cleanup
levels. Therefore, Alternative 5 does not comply with chemical
specific ARARs.
Each of the extraction alternatives, except.Alternative 6, can be
designed to comply with action-specific and location-specific
ARARs for extraction, treatment and disposal. Injection of
treated ground water may not contribute to the improvement of the
quality of the Upper Aquifer ground water and, thus, may be sub-
ject to the requirement of California Health Code 25159.10 et
seq. for injection wells. These requirements may effectively
preclude injection.
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Treatment and discharge subalternatives for Alternatives 3 thru 6
do not affect how these alternatives achieve chemical specific
ARARs. The pertinent location- and action-specific ARARs for the
treatment and discharge subalterantives are described in Section
.7. Each of these subalternatives are expected to comply with the
pertinent ARARs.
The No Action alternative does not comply with chemical specific
ARARs.
REDUCTION OF TOXICITY. MOBILITY. OR VOLUME THROUGH TREATMENT
Alternative 2 affords no reduction of toxicity, mobility or
volume of ground water containing VOCs.
Alternatives 3, 4, and 6 would employ groundwater extraction sys-
tems that will reduce the VOC concentrations in the Upper Aquifer
to or below cleanup levels. Therefore, Alternatives 3, 4, and 6
will reduce the volume of contaminants in the Upper Aquifer,
thereby reducing the toxicity of the ground water.
Alternative 3, 4, and 5 prevents the migration of VOCs in the Up-
per Aquifer by increasing the upward hydraulic gradient between
the Upper and Deep Aquifers, thus reducing the risk of downward
migration. In addition, the capture zone created by the opera-
tion of the extraction system prevents the lateral migration of
VOCs in the Upper Aquifer.
Alternative 4 captures ground water with concentrations of TCE
greater than 100 ppb using 18 of the NBES and SSES extraction
wells. Therefore, this alternative provides less reduction of
toxicity, mobility, or volume than Alternatives 3, 5, and 6.
Alternative 6 will capture ground water in excess of cleanup
levels thus reducing the toxicity and volume of contamination.
However, by reinjecting treated water into the Upper Aquifer, the
upward gradient between the Deep and Upper Aquifer would not be
enhanced and would potentially be reversed. In addition, rein-
jection may result in further spreading of the VOC plume in the
Upper Aquifer.
In conclusion, Alternative 6 will provide less reduction of
toxicity, mobility, or volume than Alternatives 3 and 5.
All of the treatment and disposal options considered for Alterna-
tives 3 thru 6 will provide reduction of volume, toxicity or
mobility through treatment. Treatment by the POTW is the only
subalternative that does not provide destruction of VOCs. This
subalternative effectively reduces the toxicity of VOCs contained
in water, primarily through stripping of VOCs in sewer pipe and
in the aeration basins of the POTW.
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LONG-TERM EFFECTIVENESS AND PERMANENCE
Alternative 2 does not provide any treatment to reduce the level
of contamination in the Upper Aquifer, thus the risk associated
with the contamination of the Upper Aquifer would remain. This
alternative does not provide a long-term effective and permanent
remedy.
Alternatives 3, 4, 5, and 6 employ extraction and treatment tech-
nologies that have proven successful in remediating VOC-affected
ground water. The North Bayshore and the Spring Street extrac-
tion systems would reliably and effectively capture VOC-affected
ground water within the Study Area as long as the operation and
maintenance of the system is properly managed.
Alternatives 3. 5, and 6 will provide a carcinogenic risk ranging
from 2.3 x 10~6 to 1.7 x 10~6 with a hazard index range of ap-
proximately 0.034 to 0.028 for the Shallow Zone and the Inter-
mediate Zone, respectively.
Alternative 4 will extract VOC-contaminated ground water contain-
ing an excess of 100 ppb TCE. It will, therefore, leave a
greater mass of VOCs in the ground water than Alternatives 3, 5,
and 6. The long-term health risks associated with the contamina-
tion that is not captured with this alterantive range from 3.5
xlO to 2.9 x 10 with an estimated hazard index of ap-
proximately o.53 to 0.54 for Shalllow Zone and Intermediate Zone
ground water, respectively.
The evaluation of long-term effectiveness and permanence for the
treatment and discharge subalternatives is as follows:
Air stripping systems are durable, with generally little need for
replacement of components with the exception of change-out of
vapor phase carbon. Regeneration of spent carbon will not create
unacceptable long-term risks. Co-combustion with landfill gases
does not create unacceptable long-term risks. Treatment
residuals are expected to be negligible. The long-term health
risk is not affected by this treatment subalternative.
Treatment by aqueous phase granular activated carbon is reliable
for the removal of VOCs from the ground water. Carbon treatment
systems are durable, with generally little need for replacements
of components. The long-term hypothetical health risk is not "af-
fected by this treatment subalternative.
Treatment by photolysis combined with oxidation is reliable for
the removal certain VOCs from water. However, the durability of
the technology is not established . The long-term hypothetical
health risk is not affected by this treatment subalternative.
The No Action alternative does not provide long-term effective-
ness and permanence.
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SHORT-TERM EFFECTIVENESS
Alternative 2 does not include implementing a remedy, therefore,
there is no added risk to workers, site employees, and residents
resulting from construction in the Study Area, since Alternative
2 provides no effective measure for remediating groundwater and
soil contamination, all risks associated with the presence of
this contamination remain unaffected.
Alternatives 3, 4 and 6 employ the existing groundwater extrac-
tion systems without modifications. Therefore, no new risks
would result from the installation of new wells. Alternative 3
is expected to achieve cleanup levels in 30 to 160 years. Alter-
native 4 is expected to achieve the remedial goal of 100 ppb to-
tal VOCs is 10 to 80 years. Alternative 6 is expected to achieve
cleanup levels in 40 to 200 years.
Alternative 5 includes the expansion of existing the existing
groundwater extraction systems. Seven new extraction wells would
be installed, and trenching required for installation of piping
would not expose VOC-affected soil, but drilling would expose.
both VOC-contaminated soils and ground water. This would in-
crease the short-term risk associated with implementation.
Proper health and safety plans should minimize these risks. The
estimated time to achieve background levels in the Upper Aquifer
is 40 to 200 years.
The evaluation of the treatment and discharge subalternatives is
as follows:
Potential risk resulting from discharging to the sanitary sewer
for treatment at the POTW include the risks caused by air emis-
sion of VOCs that would be volatilized within the sedimentation
and aeration basins and the sanitary sewer. The BPHE determined
these risks were insignificant. Time to reach remedial goals is
not affected by this subalternative.
Potential risks resulting from employing an air stripper includes
overflow of the air stripping tower(s) and emissions from the air
stripping tower(s). Controlling emissions from an air stripper
with either vapor phase carbon or by co-combustion includes
potential risks. Risks associated with managing activated carbon
are minimized by employing proper hazardous waste management
practices. However, the risks associated with co-combustion are
not completely understood. Therefore, short term risks may be
greater with this vapor phase control measure. The time to reach
remedial goals is not affected by this subalternative.
Potential risks which result from employing activated carbon in-
cludes possible dermal contact or injestion of contaminated
material. Transportation and disposal or regeneration of spent
carbon may involve other risks. These risks may be minimized
with proper waste management practices. The time to reach
remedial goals is not affected by this treatment alternative.
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Potential risk which result from employing a photolysis and
oxidation process includes fugitive emissions of ozone. This
risk is most easily mitigated by using hydrogen peroxide as an
oxidant rather that ozone. The time to reach remedial goals is
not affected by this treatment subalternative.
The No Action alternative does not include implementing a remedy,
therefore, there is no added risk to workers, site employees, and
residents resulting from construction in the Study Area. Since
the No Action alternative provides no effective measure for
remediating groundwater and soil contamination, all risks as-
sociated with the presence of this contamination remain unaf-
fected.
IMPLEMENTABILITY
Alternative 2 is an institutional program which may be imple-
mented. There is no type of construction associated with this
alternative.
The groundwater extraction systems for Alternative 3 and 6 are
completely implemented. Alternative 4 only requires the closure
of existing extraction wells, therefore, this groundwater extrac-
tion system may be implemented. Alternative 5 requires the addi-
tion of extraction wells in the Study Area which are easily
implemented.
The evaluation of the treatment subalternatives is as follows:
Discharging to the POTW requires a connection to the sanitary
sewer which is already implemented.
Constructing an air stripping system with vapor controls is easy
to achieve. However, the siting is contingent upon having
private land owner(s) or City approval for property use. Poten-
tial locations for the air stripping system have already been
identified. Vapor phase carbon is easy to implement, with high
reliability and no identified technical problems associated with
this process option. Implementing co-combustion is uncertain and
would require a pilot treatment study.
Implementing activated carbon will also depend on available
property for staging the system. The use of aqueous phase carbon
is implementable, with high reliability and no identified techni-
cal problems associated with this process option.
Implementing a photolysis/oxidation system will also depend on
available property for staging the system. Construction of a
photolysis/oxidation system may require bench and/or pilot test-
ing.
The No Action alternative may be implemented.
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COST
As a basis for comparison, the cost figures provided for Alterna-
tives 3 thru 6 assumes that the groundwater extraction systems
included in each of these alternatives will be dishcarging under
permit to the sanitary sewer for treatment at the POTW.
For Alternative 2, the capitol cost is $124,800; the annual
operation and maintenance cost is $198,740, and the present worth
for 30 years is $2,498,048.
For Alternative 3, the capitol cost is $0; the annual operation
and maintenance cost is $720,739, and the present worth for 30
years is $10,496,757.
For Alternative 4, the capitol cost is $676,475; the annual
operation and maintenance cost is $470,390; and the present worth
for 30 years is $7,522,902.
For Alternative 5, the capitol cost is $1,141,523; the annual
operation and maintenance cost is $548,341; and the present worth
for 30 years is $9,334,872.
For Alternative 6, the capitol cost is $1,125,244; the annual
operation and maintenance cost is $497,395, and the present worth
for 30 years is $8,535,426.
SUPPORT AGENCY ACCEPTANCE
The Feasibility Study and the Proposed Plan Fact Sheet were
reviewed by California Regional Water Quality Control Board
(RWQCB). The RWQCB concurs with EPA's preferred alternative.
COMMUNITY ACCEPTANCE
The Proposed Plan was presented to the community of Mountain View
in a fact sheet and at a public meeting. No technical comments
were submitted regarding the alternatives. Other comments
received are addressed in the Response Summary.
THE SELECTED REMEDY
The selected remedy for the Off-Site area is Alternative 3. Al-
ternative 3 consists of continuing the current groundwater ex-
traction system. Extracted water will be discharged to the
sanitary sewer. The current groundwater extraction system con-
sists of 22 groundwater extraction wells; 14 Shallow Zone and 8
Intermediate Zone extraction wells. The flow rate of the system
is approximately 350 gpm.
The extraction systems for Alternatives 3, 5, and 6 were designed
to achieve cleanup levels in the Upper Aquifer. The extraction
system for Alternative 5 was determined to be more difficult to
implement that Alternatives 3 and 6 due to landowner access.
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With respect to the treatment and disposal options considered,
all options provide essentially the same level of protection of
human health and the environment; are equally capable of achiev-
ing ARARs; and provide reduction of toxicity, volume, mobility,
or volume. Thus the principle differences are feasibility and
cost. Discharge to the POTW appears to be the most feasible al-
ternative. It is also the least costly, unless project life ex-
tends for an extensive time period. Significant feasibility
issues exist for the air stripping/co-combustion option (such as
treatment facility siting and the technical feasibilty of co-
combustion)-, although this option could be the most cost-
effective for longer project lives, if these issues are resolved
in a satisfactory manner.
10.0 STATUTORY DETERMINATIONS
The selected remedies are protective of human health and the en-
vironment, comply with federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and are cost-effective. This remedies utilize permanent
solutions and alternative treatment (or resource recovery) tech-
nologies to the maximum extent practicable and satisfy the
statutory preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as a principal element.
Because the remedies will result in hazardous substances remain-
ing on-site above health-based levels, a five-year review, pur-
suant to CERCLA Section 121, 42 U.S.C. Section 9621, will be con-
ducted at least once every five years after initiation of the
remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
In the Proposed Plan for Teledyne Semiconductor and Spectra-
Physics that was issued in November 1990, the recommended alter-
natives for the Teledyne On-Site area and the Spectra-Physics
On-Site area were not the same alternatives selected in this
Record of Decision. An explaination for not selecting the alter-
natives recommended in the Proposed Plan is provided in this sec-
tion.
The Proposed Plan recommended Alternative 2 for the Teledyne On-
Site area. Alternative 2 provides groundwater extraction from
the existing system which discharges under permit to the sanitary
sewer system. The remedy selected in this document is Alterna-
tive 3 which also provides for groundwater extraction from the
existing wells followed by treatment with an air stripping unit.
Treated water will be discharged under an NPDES permit to the
sanitary sewer or will be reused. Presently, this extraction
system is discharging to the sanitary sewer under a permit issued
by the City of Mountain View which permits total organics equal
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to or less than 1 ppm. The Teledyne On-Site area extraction sys-
tem is not meeting the City of Mountain View discharge require-
ments. Therefore, a treatment system is required.
The Proposed Plan recommended Alternative 5 for the Spectra-
Physics On-Site area. Alternative 5 provides for soil remedia-
tion by expanding the existing soil vapor extraction system and
provides for groundwater remediation with the addition of two
Shallow Zone extraction wells at the Spectra-Physics facility.
The remedy selected in this document is Alternative 4 which
provides for soil remediation by expanding the existing soil
vapor extraction system and provides for groundwater remediation
with the Teledyne On-Site extraction system. Alternative 5 was
originally proposed for the following reasons: .
1. The Spectra-Physics On-Site area may not be adequately
captured with the Teledyne On-Site extraction wells;
2. By adding the additional extraction wells, it was estimated
that the time to clean up ground water would be reduced by
40% according to Spectra-Physic's groundwater model;
3. Two extraction wells at the Spectra-Physics On-Site area
would provide additional source control.
Based on comments provided by Spectra-Physics during public com-
ment period, and a review of information contained in the ad-
ministrative record for the sites, the RWQCB and EPA have
selected Alternative 4 with a requirement that the effectiveness
of the system be evaluated in two years, November, 1993.
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