United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R09-91/072
August 1991
Superfund
Record of Decision
Micro Storage/Intel
Magnetics, CA
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50272-101
REPORT DOCUMENTATION 1. REPORT NO. 2.
PAGE EPA/ROD /RO 9- 91/072
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Micro Storage/Intel Magnetics, CA
First Remedial Action - Final
7. Author(s)
9. Performing Organization Name and Address
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. Recipient- s Accession No.
5. Report Date
08/26/91
6.
8. Performing Organization Rept No.
10. Project/Taak/Work Unit No.
11. Contract
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EPA/ROD/R09-91/072
Micro Storage/Intel Magnetics, CA
First Remedial Action - Final
Abstract (Continued)
the combined MSC/IM site; and replacing the underground storage tank and excavating
contaminated soil at the IM site. Treated ground water is discharged to a storm sewage
system tributary of nearby Calabazas Creek. This Record of Decision (ROD) addresses
ground water contaminated by past facility operations. The primary contaminants of
concern affecting the ground water are VOCs including benzene, PCE, TCE, and toluene;
and other organics.
The selected remedial action for this site includes continuing ground water extraction
and treatment with carbon adsorption until clean-up standards are achieved in all
combined MSC/IM site monitoring wells; installing and sampling a minimum of two new
monitoring wells; hydraulically contain the entire 93,000 cubic yards ground water plume
above clean-up standards; maintaining hydraulic control to prohibit the further vertical
and horizontal migration of the ground water pollution; quarterly ground water
monitoring at the combined MSC/IM site during the clean-up period; treating the
extracted ground water with an existing carbon absorption system; discharging the
treated ground water onsite to Calabazas Creek; and implementing deed restrictions
onsite. The estimated present worth O&M cost for this remedial action ranges from
$630,000 to $1,100,000 for 10 years.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals are based
on the more stringent of Federal and State MCLs standards, and include benzene 1 ug/1,
PCE 5 ug/1, TCE 5 ug/1, and toluene 100 ug/1.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX
75 Hawthorne Street
San Francisco, Ca. 94105
RECORD OF DECISION
MICRO STORAGE CORPORATION/INTEL MAGNETICS
SUPERFUND SITE
SANTA CLARA, CALIFORNIA
AUGUST 26f 1991
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IX
SAN FRANCISCO, CA
Printed on Recycled Paper
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RECORD OF DECISION
PART I: DECLARATION
PART II: DECISION SUMMARY
PART III: RESPONSIVENESS SUMMARY
PART IV: AGENCY ADDENDUM TO THE REMEDIAL
INVESTIGATION REPORT
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TABLE OF CONTENTS
PART SECTION
I
I
I
I
I
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
1.0
2.0
3.0
4.0
5.0
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
2.0
2.1
2.2
2.3
3.0
4.0
5.0
5.1
FART I: DECLARATION
Declaration
Statement of Basis and Purpose
Assessment of the Site
Description of the Remedy
Statutory Determinations
PART II: DECISION SUMMARY
Site Name, Location, and Description
Site Name and Location
Regional Topography
Climatology
Adjacent and Historical Land Use
Hydrogeology
* **•-
Water Use
Surface and Subsurface Structures
Site History and Enforcement Activities
History of Enforcement Actions
History of Site Investigations
History of Site Activities
Community Relations
Scope and Role of the Response Action
Summary of site Characteristics
Sources of Contamination
l
1
1
1
3
1
1
1
2
2
2
3
4
8
8
9
10
12
13
16
16
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TABLE OF CONTENTS coxrb'd
PART SECTION PAGE
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
5.2
5.3
6.0
6.1
6.2
6.3
6.4
6.5
7.0
7.1
7.2
7.3
7.4
8.0
9.0
9.1
10.0
11.0
Description of Contamination
Conclusion
Summary of Site Risks
Contaminant Identification
Exposure Assessment
Toxicity Assessment
Risk Characterization
Presence of Sensitive Human Populations
Presence of Sensitive Ecological Systems
Conclusion
Applicable or Relevant and Appropriate
Requirements (ARARs)
Types of ARARs
Contaminant-Specific ARARs and TBCS
Action Specific ARARs and TBCS
Location-Specific ARARs
Description of Alternatives
Comparative Analysis of Alternatives
Ground Water
Statutory Determinations
Documentation of Significant Changes
PART III: RESPONSIVENESS SUMMARY
17
18
22
22
23
23
24
26
26
27
39
40
40
41
43
46
48
49
58
58
III Responsiveness Summary 60
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LIST OF FIGURES
FIGURE TITLE PAGE
Figure 1 Micro Storage/Intel Magnetics Locality Map 6
Figure 2 Micro Storage/Intel Magnetics Site Map 7
Figure 5.1 Wells and Geologic Cross-Section Location Map 19
Figure 5.2 Site Vicinity, Monitoring/Extraction Well
Locations (September 1989) 20
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TABLE
LIST OF TABLES
TITLE
PAGE
Table 4.1
Table 5.3
Table 6.1
Table 6.2
Table 6.3
Table 6.4
Table 6.5
Table 6.6
Table 6.7
Table 6-8
Table 6-9
Table D-l
Table 1
Groundwater Cleanup Standards 15
Concentrations of Chemicals Detected in
Groundwater Samples A-Zone 21
Concentrations of Chemicals Detected in
Groundwater Samples A-Zone 28
Physical/Chemical Properties of the Organic
Chemicals of Potential Concern 29
Human Exposure Pathways for Micro Storage/Intel
Magnetics Under Current-Use Conditions 30
Human Exposure Pathways for Micro Storage/Intel
Magnetics Under Future-Use Conditions 32
Critical Oral Toxicity Values 33
Critical Inhalation Toxicity Values 34
Future-Use Scenario Chronic Daily Intakes
and Potential Risks due to Ingestion of
Groundwater and Inhalation of Volatiles 35
Determination of Excess Lifetime Carcinogens
Risk Based on Clean-Up Standard 37
Determination of Total Hazard Index for
Non-Carcinogens Based on Clean-Up
Standards
Documentation of ARARs
Comparison of Alternatives
38
44
53
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DECLARATION
1.0 SITE NAME AND LOCATION
MICRO STORAGE CORPORATION /INTEL MAGNETICS SUPERFUND SITE
Santa Clara, California
Micro Storage Corporation
Former Micro Storage Facility
2986 Oakmead Village Court
Santa Clara, Santa Clara County
Intel Corporation
Former Intel Magnetics Facility
3000 Oakmead Village Drive
Santa Clara, Santa Clara County
2.0 STATEMENT OF BASIS AND PURPOSE
This Record of Decision ("ROD") presents the selected
remedial actions for the Micro Storage Corporation/Intel Mag-
netics Superfxind sites in Santa Clara, California. This document
was developed in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA) as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA), 42 U.S.C. Section 9601 et. seq.. and to the extent
practicable the National Oil and Hazardous Substances Pollution
Contingency Plan, 40 C.F.R. Section 300 et. seq.. ("NCP"). This
decision is based on the administrative record for this site.
The State of California concurs with the selected remedy.
3.0 ASSESSMENT OP 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 OP THE REMEDY
The remedial actions address the principal threat remaining
at the Micro Storage Corporation/Intel Magnetics sites by remov-
ing the contaminants from ground water, thereby significantly
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reducing the toxicity, mobility or volume of hazardous substances
in the media. These response actions will greatly reduce the
possibility of contamination of existing potable water supplies
and potential future water supplies.
This action represents the final remedial action to remove
contaminants from groundwater. The major components of the
selected remedy include the following:
a. Continued groundwater extraction until drinking water stan-
dards for TCE (5 ppb); 1,1-DCA ( 5 ppb); 1,1-DCE (4 ppb);
cis 1,2-DCE (6 ppb); trans 1,2-DCE ( 10 ppb); Freon 113
(1200 ppb); Methylene Chloride (40 ppb); PCE ( 5 ppb);
Toluene (100 ppb); 1,1,1-TCA (200 ppb); 1,1,2 TCA ( 32 ppb);
chloroform (100 ppb) are achieved in all combined MSC/IM
site monitoring wells.
b. Hydraulic containment of the entire groundwater plume above
cleanup standards and continued groundwater extraction at
the four existing wells. Modifications to the system is re-
quired in the event that the interim hydraulic control sys-
tem is demonstrated not to be effective in containing and
removing the groundwater pollutants.
c. Maintenance of hydraulic control to prohibit the further
vertical and horizontal migration of the groundwater pollu-
tion. This requirement shall remain in effect until cleanup
standards are achieved.
d. Continued quarterly groundwater monitoring at the combined
MSC/IM site during the cleanup period. Water samples will
continue to be collected to verify that cleanup is proceed-
ing and that there is no migration of VOCs, above cleanup
standard levels, beyond current boundaries or into the
deeper B zone. The frequency of monitoring will be
decreased from quarterly to triannually two years after ap-
proval of a report submitted in compliance with Provision
C.4.a. (hydraulic control) of the RWQCB Order. The fre-
quency of monitoring will be further decreased to biannually
once cleanup standards have been achieved and stabilized for
one year. Detailed sampling and reporting requirements for
the combined MSC/IM site are contained in the RWQCB's Self-
Monitoring Plan.
-«—v "-£? •--•%
e. Treatment of extracted groundwater with an existing carbon
adsorption system. The treated groundwater will continue to
be discharged to Calabazas Creek, pursuant to a NPDES per-
mit.
f. File a deed restriction prohibiting use of on-site shallow
groundwater for drinking water and controlling other subsur-
face activities. The deed restriction shall remain in place
until groundwater cleanup standards are achieved.
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5.0 STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, 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) technologies to the maximum extent practicable and
satisfies the statutory preference for remedies that employ
treatment that reduces toxicity, mobility, or volume as a prin-
cipal 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.
John W§^e Date
Deputy Regional Administrator
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX
75 Hawthorne Street
San Francisco, Ca. 94105
Concurrences for
MICRO STORAGE/INTEL MAGNETICS SUPERFUND SITE
RECORD OF DECISION
Seraydarian, Director Date
Water Management Division
Printed on Recycled Paper
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PART II. DECISION SUMMARY
This Decision Summary provides an overview of the problems
posed by the Micro Storage Corporation/Intel Magnetics Superfund
sites ("the Study Area" or "MSC/IM"), the remedial alternatives,
and the analysis of the remedial alternatives. This Decision
Summary explains the rationale for the remedy selection and how
the selected remedy satisfies the statutory requirements of
CERCLA.
1.0 SITE NAME, LOCATION, AND DESCRIPTION
1.1 SITE NAME AND LOCATION
MICRO STORAGE CORPORATION/INTEL MAGNETICS
Former Micro Storage Facility
2986 Oakmead Village Court
Santa Clara, Santa Clara County, CA
Intel Corporation
Former Intel Magnetics Facility
3000 Oakmead Village Drive
Santa Clara, Santa Clara County, CA
The combined Micro Storage Corporation/Intel Magnetics site
is located in the City of Santa Clara in a relatively flat lying
portion of the Santa Clara Valley approximately 50 miles south of
San Francisco (see Figure 1). Ground surface elevations are
generally between 35 feet and 41 feet above mean sea level. This
is an industrial park setting, dominated by the electronics in-
dustry, particularly semiconductor manufacturing. As such, the
majority of the area is developed, with large paved areas for
streets and parking lots. Surface water is controlled by the
storm sewer system which directs runoff to Calabazas Creek. The
nearest residential areas are located 1200 feet south of the
site. Other residential areas are located 6000 feet north-
northeast of the combined Micro Storage Corporation/Intel Mag-
netics site. None of these residential areas are within the area
impacted by the past chemical releases from the combined MSC/IM
site.
1.2 REGIONAL TOPOGRAPHY
The Study Area is located near the center of the Santa Clara
Valley which extends southeast from San Francisco Bay and is
bounded by the Diablo Range on the northeast, and by the Santa
Cruz and Gabilan Ranges on the southwest.
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The Santa Clara Valley is a large structural depression in
the Central Coastal Ranges of California. The Valley is filled
with alluvial and fluvial deposits from the adjacent mountain
ranges. These deposits are up to 1,500 feet in thickness. At
the base of the adjacent mountains, gently sloping alluvial fans
of the basin tributaries laterally merge to form an alluvial
apron extending into the interior of the basin.
1.3 CLIMATOLOGY
The San Francisco Bay area has pronounced wet and dry
seasons with mild wet winters and warm dry summers characteristic
of a Mediterranean climate. The Santa Clara Valley lies in the
path of winter storms which periodically sweep inland from the
North Pacific. Freezing temperatures and snow are extremely
rare. Rainfall from the winter storms ranges from moderate to
heavy. Records from the Santa Clara Valley Water District show
the average annual rainfall to be about 14 inches. The site
averages approximately 10 to 14 inches of rainfall per year.
Over 75% of the total annual rainfall in this area occurs during
the winter months of November through March. The average annual
wind speed is approximately 6 to 7 mph (about 3 m/sec) with
slightly stronger winds occuring in the summer. Winds in the
area are predominantly from the north and northwest.
1.4 ADJACENT AND HISTORICAL LAND USE
Land use in the general vicinity of the site was primarily
agricultural until the 1970's when light industrial and commer-
cial development began. The MSC/IM site is located in an in-
dustrial park (see Figure 2). The closest residences are ap-
proximately one-half mile to the south and one mile to the
northwest. Both residential areas contain predominantly single
family residences built on concrete slabs. Several elementary
schools are included in each of these residential areas. The
campus of Mission College is located approximately one mile north
of the site. There are no day care centers or convalescent homes
located in the immediate vicinity of the site.
1.5 HYDROGEOLOGY
Regional Hydrogeology
— .B.I "•£!•*-
The Santa Clara Valley groundwater basin is divided into two
broad areas: l) the forebay, and 2) the confined area, where the
combined MSC/IM site is located. The forebay occurs along the
elevated edges of the basin where the basin receives its prin-
cipal recharge. The confined area is located in the flatter in-
terior portion of the basin and is stratified or divided into in-
dividual beds separated by significant aguitards. The confined
area is divided into the upper and lower aquifer zones. The
division is formed by an extensive regional aguitard that occurs
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at depths ranging from about 100 feet near the confined area's
southern boundary to about 150 to 250 feet in the center of the .
confined area and beneath San Francisco Bay. Thickness of this
regional aquitard varies from about 20 feet to over 100 feet.
Several aquifer systems occur in the upper aquifer zone
separated by aquitards which may be leaky or very tight.
Groundwater pollution at the combined MSC/IM site is confined to
the shallowmost zone within the upper aquifer zone. The lower
aquifer zone occurs beneath the practically impermeable regional
aquitard. Numerous individual aquifers occur within this
predominantly aquitard zone and all groundwater in this zone oc-
curs confined.
Municipal water supply wells are generally perforated in the
lower aquifer zone. Perforated intervals in City of Santa Clara
water supply wells located within 2 miles of the combined MSC/IM
site begin from 250 to 320 feet below ground surface, although
sanitary seals are only installed down to 100 feet below ground
surface. Currently, the nearest municipal drinking water supply
well downgradient of the combined MSC/IM site is the City of
Santa Clara's Well No. 33 located 1.8 miles north of the combined
MSC/IM site. No contaminants have been found in this well to
date.
Site Hydrogeology
Two shallow aquifer zones have been identified beneath the
combined MSC/IM site. These shallow aquifer zones are subdivi-
sions of the upper aquifer zone described in the regional
hydrogeology section. The shallowest, or A aquifer zone (A
zone), has its upper boundary at about 10 feet below ground sur-
face (BGS), and lower boundary about 20 feet BGS. The B aquifer
zone (B zone) lies between about 30 and 40 feet BGS. The two
zones are separated by a 2 to 10 feet thick aquitard composed of
clay to silty sand. It is suspected that hydraulic separation
between the two zones is imperfect owing to the discontinuous na-
ture of sediment types. Shallow groundwater flow in the A and B
zone, beneath the combined MSC/IM site, is generally to the
north-east. This flow regime is consistent with the northerly
regional flow towards the San Francisco Bay.
1.6 WATER USE
The combined MSC/IM site overlies the Santa Clara Valley
groundwater basin. Groundwater from this basin provides up to
50% of the municipal drinking water for the 1.4 million residents
of the Santa Clara Valley. In 1989, groundwater accounted for
approximately 128,000 of the 315,000 acre feet of drinking water
delivered to Santa Clara Valley Water District customers. Ap-
proximately 300,000 people residing within a 3-mile radius of the
Study Area depend on local groundwater for drinking purposes.
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The existing and potential beneficial uses of the
groundwater underlying and adjacent to the combined MSC/IM site
include:
a. Industrial process water supply
b. Industrial service water supply
c. Municipal and Domestic water supply
d. Agricultural water supply
Groundwater Conservation
The potentially responsible parties considered the
feasibility of reclamation, reuse, or discharge to a publicly
owned treatment works in its NPDES permit application dated
January 23, 1990. Based on this evaluation, as well as further
evaluation in the FS, the Regional Water Quality Control Board
(RWQCB) determined that groundwater reclamation, reuse, or dis-
charge to a POTW at the combined MSC/IM site was not feasible.
1.7 SURFACE AND SUBSURFACE STRUCTURES
The one acre site at 2986 Oakmead Village Court is developed
with a single story, tilt-top structure. The building is sur-
rounded with concrete or asphaltic pavement. Less than 10% of
the property is unpaved and consists of landscaped areas on the
borders of the property. Storm drains which discharge to the
Calabazas Creek collect storm runoff water from the flat site
area.
Chemicals used in on-site processes at Micro Storage were
stored in an external shade storage area located on the west side
of the building on a concrete platform. Large quantities were
contained in 55-gallon drums which were stored on wood pallets
inside the shade area. Other chemicals were contained in
5-gallon or less containers which were stored in a metal cabinet
inside the shade storage area as well.
The former IM operations were housed at 3000 Oakmead Village
Court in a single story structure located on approximately 2
acres of property. Approximately 90% of the site is covered with
buildings or pavement. The only unpaved areas are the landscaped
areas located on the borders of the facility. Storm drains which
discharge to the Calabazas Creek collect storm runoff water from
the nearly level site area.
As reported in its response to a facility questionnaire
issued by the RWQCB (1982), IM operated a 500-gallon underground
waste solvent tank and a 1000-gallon, in-ground, cement-lined
acid neutralization system on the site along with associated un-
derground piping. In addition, several shaded exterior storage
areas were observed on the southwest side of the building during
a site visit in 1989.
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The underground storage tank was installed in 1978 and was
used to store waste solvents which typically consisted of 70%
water, 25% isopropanol, and small amounts of Freon, N-butyl
acetate, Hunt Developer, acetone, xylene, and polymer solids. In
July 1985, as a result of on-going soil and groundwater con-
tamination studies, Intel removed the solvent tank and installed
a new underground 1000-gallon, double-walled stainless steel tank
in an adjacent excavation.
The acid neutralization system was installed in 1978. The
system consisted of three underground compartments in which a
dilute acid waste stream containing hydrochloric, hydrofluoric,
acetic, phosphoric, and sulfuric acids was neutralized prior to
discharge to the sanitary sewer. According to RWQCB documents
approximately 2000 gallons of wastewater was treated per day.
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Micro Storage/
,i Intel Magnetics Site
^X •OUNOAMVMFTWCENGONrMCOlONCMIDUNCONrMCDZONE
AT CONFMfO 20NC Bf ME ATM CENTER OF BASH. UNCONFMEO ZONE
/ OCCURS MONO (ASM MAMQM
Figure 1. Micro Storage/Intel Magnetics Locality Map
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Metropolitan
Corporate Center
AMI tO
ROAD
UGCND
v • AppTOnfltttc radtlon of ntoniionnt ^*cu
© • Appnulmie kxaOon of extraction well
Figure 2. ' Micro Storage/Intel Magnetics Site Map
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2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 HISTORY OF ENFORCEMENT ACTIONS
Pursuant to the South Bay Multi-Site Cooperative Agreement
and the South Bay Ground Water Contamination Enforcement Agree-
ment, entered into on May 2, 1985 (as subsequently amended) by
the Regional Water Quality Control Board ("the Board" or
"RWQCB"), EPA and the California Department of Health Services
(DHS), the Board has been acting as the lead agency for the com-
bined MSC/IM site. The combined MSC/IM site is on the NPL and
has been regulated by RWQCB Orders.
Kim Camp III (KCIII) is the property owner of the former
Micro Storage Corporation Facility (MSC site) located at 2986
Oakmead Village Court, Santa Clara (Figures 1 and 2). Micro
Storage Corporation (MSC) occupied the MSC site from January 1985
to December 1986, and used the MSC site for research and develop-
ment and pilot manufacturing of microcomputer disk drives. The
chemicals used by MSC included Freon 113 and other unspecified
nonflammable/chlorinated solvents, which have been found in the
groundwater at the MSC site. EPA and RWQCB staff was advised by
Counsel for MSC that MSC was dissolved as a corporation by the
State of California on August 16, 1988.
3000 Oakmead Village Drive Limited (OVDL) is the property
owner of the former Intel Magnetics Facility (IM site) located at
3000 Oakmead Village Drive, Santa Clara. Intel Magnetics (IM), a
wholly owned subsidiary of the Intel Corporation (Intel), oc-
cupied the IM site from 1978 to 1987, and operated a magnetic
bubble production and testing facility at the IM site. An under-
ground solvent tank and an in-ground acid neutralization system
were formerly operated by IM at the facility. Chemicals used in
IM operations included isopropanol, Freon, chlorinated hydrocar-
bons (unspecified, but reportedly does not include
tetrachloroethene and 1,1,1,-trichloroethane), N-butyl acetate,
Hunt Developer (isodecane C,^ and C12), acetone, xylene, dilute
acids, and the metals arsenic, chromium, lead, and tin. Among
others, TCA and Freon 113 have been found in the groundwater at
the IM site.
The IM site was placed on the National Priority List (NPL)
in May 1986. In 1988 the MSC site was included with the IM site
as one combined Superfund site. EPA conducted a PRP Search from
August 1990 to December 1990 and MSC, Kim Camp III, Kimball Small
Investments III, Westall Corporation, Campeau Corporation
California, Intel, and Oakmead Village Drive Limited were iden-
tified as Potentially Responsible Parties under Federal Superfund
(CERCLA/SARA) regulations.
8
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The following is a chronology of important Micro Storage
Corporation/Intel Magnetics regulatory activities.
a. June 16, 1982 Intel submits completed Board Facility Ques-
tionnaire.
b. March 19, 1986 Board adopted NPDES Permit No. CA0028941
(Order No. 86-014), for the discharge of treated extracted
groundwater at the IM site.
c. May 1986 IM site added to the final NPL.
d. February 2, 1987 KCIII submits its tenants' Hazardous Chemi-
cal Use History Report. October 12, 1988, EPA changes name
of site from IM to the combined MSC/IM site.
d. February 15, 1989 Board adopted Order No. 89-017 issuing
Site Cleanup Requirements to MSC and KCIII.
e. March 17, 1989 Board adopted Order No. 89-086 amending Site
Cleanup Requirements to MSC, KCIII, Intel, and OVDL
(approving RI/FS workplan and rescinding Order No. 89-017).
f. March 21, 1990 Board adopted NPDES Permit No. CA0029670
(Order No. 90-040), for the discharge of treated extracted
groundwater at the combined MSC/IM site.
2.2 HISTORY OF SITE INVESTIGATIONS
In early 1982, the Regional Board initiated a leak detection
program to define the extent of leakage from underground storage
tanks and pipes in the South Bay area. As a result of these ef-
forts, subsurface investigations at the IM site detected
trichloroethene (TCE), trichlorethane (TCA), and Freon-113 in the
A aquifer zone (the shallowest or first encountered aquifer below
the ground surface) at the IM site.
Based on the results from wells installed on the upgradient
MSC site, the Board requested that KCIII conduct additional in-
vestigation on the MSC site. A September 1988 technical report
prepared by Jacobs Engineering, a consulting firm under contract
to EPA, concluded that, "A primary source of VOC contamination is
indicated at the Micro Storage facility where maximum levels of
VOC concentrations including trichloroethylene (TCE), 1,1,1-
trichloroethane (TCA), and Freon 1123 are found". The Jacobs En-
gineering Report also concluded that, "a secondary source of
Freon 113 and possibly TCA is believed to exist at the Intel Mag-
netics site...".
Based on the new information, submitted in late 1987 and
early 1988, regarding groundwater pollution at the upgradient MSC
site, EPA changed the name of the Superfund site from the Intel
9
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Magnetics site to the combined Micro Storage Corporation/Intel
Magnetics site. In making this change, EPA, in an October 12,
1988 letter to Board staff, stated that "Intel is still a respon-
sible party...". Since October 1988, EPA and the Board have
regulated the MSC site and the IM site as one combined Superfund
site.
In May 1990 the Board adopted Order No.89-086 which approved
the Remedial Investigation/Feasibility Study (RI/FS) workplan.
Order No. 89-086 was an interim Order which remained in effect
while the RI/FS was being completed. The RWQCB adopted Order No.
91-119 on July 17, 1991. This Order requires MSC/IM to implement
remedial actions that are equivalent to the remedy chosen in this
Record of Decision.
2.3 HISTORY OF SITE ACTIVITIES
Interim Remedial Actions
Interim remedial measures (IRMs) at MSC have included the
extraction of contaminated groundwater and the removal of all
chemicals stored on the combined MSC/IM site. IRMs at the IM
site have included the extraction of polluted groundwater, the
replacement of the underground solvent tank and excavation of
contaminated soils.
Between 1986 and 1990 Intel extracted and treated
groundwater from two IM site wells. The treated water was dis-
charged to a storm sewer system tributary of Calabazas Creek as
specified under NPDES Permit #CA0028941.
In January 1991, KCIII began operation of an expanded
groundwater extraction and treatment system on the MSC site.
This system pumps water from an existing IM site extraction well
and three new extraction wells located on the MSC site. The
treated water is discharged to a storm sewer system tributary of
Calabazas Creek as specified under NPDES Permit #CA0029670.
Metropolitan Corporate Center
A separate VOC groundwater plume has been identified beneath
a property located immediately west of the MSC site (see Figure
2). The property, known as the Metropolitan Corporate Center
(MCC), is located at 3165^-Kifer Road, Santa Clara and owned by
the Metropolitan Life Insurance Company (Metropolitan). TCE has
been detected in groundwater monitoring wells at levels up to 180
ppb and in reconnaissance groundwater samples at levels up to 400
ppb. To date, no source has been located for the MCC plume. No
underground solvent storage tanks are known to have been in-
stalled at the MCC property. While the lateral and vertical ex-
tent of the MCC plume has not been completely defined, data sub-
mitted by both Metropolitan and KCIII indicate that either the
10
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plumes are not commingled or they are only commingled near the
lateral leading edge at levels less than approximately 50 ppb to-
tal volatile organic compounds.
The RWQCB issued Site Cleanup Requirements under Order No.
91-100 on June 19, 1991 to Metropolitan for the MCC. Because the
MCC plume and the HSC/IM plume are in close proximity to each
other, Provision 2 of both the MCC Order and the Site Cleanup Re-
quirement Order for this site (Order No. 91-119) require that the
operation of any extraction system at the MCC and MSC/IM sites be
done in a coordinated effort. This coordinated effort includes
locating extraction wells and selecting pumping rates that maxi-
mize pollutant removal and minimize the hydraulic effects on the
other site's groundwater plume.
11
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3.0 COMMUNITY RELATIONS
An aggressive Community Relations program has been ongoing
for all Santa Clara Valley Superfund sites, including the com-
bined MSC/IM site, and the requirements for public participation
under CERCLA Section 113 (k) (2) (B) (i-v) have been met. The RI/FS
and Proposed Plan for Micro Storage Corporation/Intel Magnetics
was released to the public in April 1991. These two documents
were made available to the public in both the administrative
record and an information repository maintained at the RWQCB of-
fices in Oakland, CA and the Santa Clara Public Library. The
RWQCB published a notice in the Santa Clara Weekly on April 10,
1991 and April 17, 1991, announcing the RI/FS, Proposed Plan and
opportunity for public comment at the Board Hearing of April 17,
1991 in Oakland, and announcing the opportunity for public com-
ment at an evening public meeting at Bracher Elementary School in
the City of Santa Clara on April 24, 1991. A sixty day public
comment period on the RI/FS Report and the Proposed Plan ran from
April 17, 1991 to June 17, 1991. A presentation of the proposed
final cleanup plan was made at the April 17, 1991 Board Hearing
and the April 24th public meeting. Representatives from the
RWQCB and EPA attended the meeting. The RWQCB staff person
answered questions about problems at the site and the remedial
alternatives under consideration. A response to the comments
received during this period is included in the Responsiveness
Summary, which is part of this Record of Decision.
Fact Sheets for the combined MSC/IM site were mailed to in-
terested residents, local government officials, and media repre-
sentatives. Fact Sheet l, mailed in January 1990, summarized the
pollution problem, the results of investigations to date, and the
interim remedial actions. Fact Sheet 2, mailed in April 1991,
described the cleanup alternatives evaluated, explained the
proposed final cleanup plan, announced opportunities for public
comment at the Board Hearing of April 17, 1991 in Oakland and the
Public Meeting of April 24, 1991 in Santa Clara and described the
availability of further information at the Information Repository
at the City of Santa Clara Public Library.
This decision document presents the selected remedial action
for the Micro Storage Corporation/ Intel Magnetics Site, in Santa
Clara, California chosen in accordance with CERCLA, as amended by
SARA and, to the extent practicable, the National Contingency
Plan. The decision for this site is based on the administrative
record.
12
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4.0 SCOPE AND ROLE OF THE RESPONSE ACTION
This ROD addresses the entire site which consists of con-
tamination of the groundwater aquifer. The purpose of this
response is to prevent any further migration of contaminants in
the groundwater, prevent any future exposure to the public of
contaminated groundwater, and to restore the A-zone groundwater
to drinking water quality. The response action does not address
soils because investigations have not demonstrated that soils
contain contaminants at levels of concern.
For the site, twelve chemicals have been identified as the
primary contaminants of concern in the groundwater. Cleanup
standards have been assigned to all twelve chemicals. The
highest concentrations of contaminants in the A-zone groundwater
are: TCE (770 ug/1), TCA (570 ug/1), and Freon(3,400 ug/1).
DCA, DCE, and PCE have also been detected in smaller concentra-
tions.
The selected remedy presented herein addresses the docu-
mented potential threats from the site. Treatment of the con-
taminated groundwater will significantly reduce the possibility
of future migration of contaminants into a potential drinking
water source. The groundwater cleanup standards for the combined
MSC/IM site are based on Environmental Protection Agency (EPA)
maximum contaminant levels (MCLs), California Department of
Health Services (DHS) MCLs (proposed or adopted), and DHS Action
Levels. The cleanup standards are defined in Table 4.1.
As shown on Table 4.1, the groundwater cleanup standards for
all contaminants except benzene and 1,1 DCE are Federal or State
(MCLs), either adopted or proposed, whichever is more stringent.
The cleanup standard for 1,1 DCE is less than its proposed or
adopted MCL. This reduction was necessary so that the cumulative
risk associated with the cleanup standards would be within ac-
ceptable levels. The final cleanup standards for the suite of
chemicals detected in the shallow zone equate to a future use
scenario and carcinogenic risk level for groundwater ingestion
and inhalation of 1 x 10~ .
SOIL CONTAMINATION
—-v "r^-f' - •-'•'-* •
The final Remedial Investigation report concluded that the
volatile organic contaminants (VOCs) detected in the soil repre-
sent a limited release confined to the small area of the parking
lot near the former storage area. There are currently no ARARs
established for cleanup levels in contaminated soil. However, a
RWQCB policy of cleanup to background or 1 ppm total VOCs for
soils is a TBC criteria and has been set as the soil cleanup
standard. Experience at other sites has shown that this level
13
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will prevent recontamination of groundwater. Current soil condi-
tions are two orders of magnitude below 1 ppm. Because of this
low level, remedial actions for soil were not developed.
GROUNDWATER CONTAMINATION
Contaminated groundwater extends in a northeasternly direc-
tion along the approximate hydraulic gradient of the A-zone
potentiometric surface. The plume's center is currently located
near the northern property boundary of 2986 Oakmead Village Court
and impacts approximately 10,000 cubic yards of aquifer material.
The combined plume is approximately 850 feet in length and 450
feet in width at its widest point, and occupies an approximate
aquifer volume of 93,000 cubic yards.
14
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TABLE 4.1
GROUNDWATER CLEANUP STANDARDS
GROUNDWATER SELF-MONITORING PROGRAM
The Combined Micro Storage/Intel Magnetics Site
2986 Oakmead Village Court and 3000 Oakmead Village Drive
Santa Clara, Santa Clara County
(all values in ng/1)
Compound
Benzene
1,1-
Dichloroethane
cis 1,2-
Dichloroethene
trans 1,2-
Dichloroethene
1,1-
Dichloroethene
Freon 113
Methylene
Chloride
Tet r ach 1 or othene
Toluene
1,1,1 -
Trichloroethane
1,1,2 -
Trichloroethane
Trichloroethene
FEDERAL
MCLG
0
—
70
100
7
— -
(0)
0
1000
(40)PS
200
—
0
FEDERAL
MCL
5
—
70
100
7
—
(5)
5
1000
200
—
5
CA
ACTION
LEVEL
—
—
—
—
—
— .
40
—
100
—
—
—
CA
MCL
1
5
6
10
6
1200
—
5
—
200
32
5
CLEANUP
STANDARD
1
5
6
10
4
1200
40
5
100
200
32
5
MCLG Maximum Contaminant Level Goal
MCL Maximum Contaminant Level
PS Proposed Secondary MCL
() criteria in parentheses are proposed MCLs
— no criteria
15
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5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 SOURCES OF CONTAMINATION
Source In vest! grata on
The RI identified two potential source areas for the
groundwater pollution: 1) a 500 gallon underground storage tank
located on the IM site, and 2) an above ground outdoor chemical
storage area located on the MSC site.
Intel Source Investigation
A secondary source of groundwater pollution is associated
with the former underground waste solvent storage tank at IM. In
response to the RWQCB 1982 questionnaire, Intel described the
tank as a non-vaulted steel tank with a capacity of 400 gallons.
The tank was reportedly used to store approximately 350 gallons
of solvents per month. At a meeting between the RWQCB and Intel
in August, 1983, the RWQCB concluded that the contamination at
the site was the result of an overflowing tank (EPA Responsible
Party Search report dated August 28, 1985). The overflowing
fluid would have seeped into the gravel backfill that surrounded
the tank. In July 1985, the tank and 35 cubic yards of soil were
excavated from the IM site. The tank was reportedly tested both
in the ground and after its removal and found to not have any
leaks. The chemicals used by IM included TCA and Freon 113.
MSC Source Investigation
No discrete source of the groundwater contamination has been
positively located at MSC. No underground tanks, sumps, or
piping (except piping for water, natural gas, electrical or
domestic sewage) are known to have been installed at the Micro
Storage property. However, Micro Storage reported that they did
store chemicals in 55 gallon drums in an external above-ground
storage area. The chemicals used by Micro Storage included
Freon-113 and other unspecified nonflammable chlorinated sol-
vents .
Currently, the highest levels of groundwater contaminantion
are beneath the parking lot of the MSC site. Vadose zone sources
generally overlie the area of highest groundwater pollution. In
an attempt to characterize the soil pollution at the MSC site,
KCIII collected and analyzed 37 shallow soil samples collected
from 17 borings. In addition, 70 soil gas samples were collected
during three soil gas surveys. Normally these 107 data points
would be considered sufficient for characterizing an area of this
size (approximately 1 acre). However, confirmation soil and soil
16
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gas sampling has yielded contradictory results. For example, the
soil samples collected in June 1988 contained an average of ap-
proximately 120,000 parts per billion (ppb), Freon-113. Confir- "
mation soil samples collected in 1989 and 1990 contained a maxi-
mum of 6.4 ppb Freon-113. Similar contradictions are also noted
in the soil gas survey. For example, SG-10 (collected in October
1987) contained 84 ppb Freon-113. Confirmation soil gas sampling
at SG-59 (collected in April 1989) contained 2270 ppb Freon-113.
While some of the data was contradictory, the majority of
the data supports the conclusions presented in the RI that the
VOCs detected represent a limited release confined to the parking
lot near the former storage area. Soil, soil-gas and groundwater
data suggests that the original source of VOCs has leached or
volatilized out of the source area and that only low levels of
VOCs remain. These low levels are not prone to impacting the
groundwater, and no further soil action is recommended.
Vertical Conduit Study
A well search for abandoned agricultural wells within 1/2
mile radius of the combined MSC/IM site was completed in August
1989. The focus of the well search was to identify wells that
potentially may form migration pathways to the deeper aquifer.
This study also evaluated whether existing monitoring wells could
provide a conduit between the polluted A zone and the clean B
zone. The study identified three former agricultural wells
(06S1W28K02, 06S1W28K03, and 06S1W28K05) located approximately
750-1000 feet northeast of the leading edge of the plume. Well
06S1W28K05 was subsequently destroyed by Avantek Inc. in 1990.
No well destruction information was available on the other two
wells. Since these wells lie over 750 feet beyond the leading
edge of the plume, no further work was required.
The vertical conduit study also determined that four exist-
ing monitoring wells had the potential to cross contaminate the B
zone. These four wells (IM-5, 6, 8, and 9) were properly
destroyed in 1990.
5.2 DESCRIPTION OF CONTAMINATION
As a result of subsurface investigations, IM detected
trichloroethene (TCE), trichlorethane (TCA), 1,1 dichloroethene
(1,1 DCE), and Freon-113 in the A aquifer zone which is the shal-
lowest or first encountered aquifer below the ground surface.
The RI used data from twenty-nine A and B zone monitoring
and extraction wells in an attempt to define the vertical and
horizontal extent of the plume (see Figures 5.1 and 5.2). The A
zone plume covers an area approximately 850 long feet by 450 feet
wide. With the exception of monitoring well MMW-2, only one B
17
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zone sample has shown a trace level of pollution during the last
four years. This trace level is likely due to laboratory con-
tamination. Monitoring well MMW-2 appears to be screened across
both the A and B aquifers. In 1990, MMW-2 had an average con-
centration of TCE of 32 ppb. Board Order No. 91-100 requires
Metropolitan Life Insurance Company to consider replacing MMW-2
with a mono-aquifer screened well and properly destroy MMW-2.
Table 5.3 provides geometric means of concentrations of
chemicals detected in A-zone groundwater, maximum contaminant
concentrations and frequency of detection. Based on data from
the April 1991 sampling round, the only chemicals detected in the
A zone above drinking water standards were TCE, 1,1-DCE, 1,2-DCE,
and Freon-113 at maximum levels of 750, 13, 43, and 3500 parts
per billion (ppb) respectively.
5.3 CONCLUSION
EPA expects that up to 20,000 gallons (15 gpm pumping rate)
of contaminated groundwater may need to be treated each day for
approximately 10 years. Groundwater treatment remedies should be
adequate to prevent surface water releases and a surface water
remedy is not proposed at this time.
All data used to develop the Feasibility Study, to select
remedial alternatives and to develop conclusions and clean-up
standards presented in this Record of Decision were based on the
following data quality requirements:
1) All data were collected under the guidance of a Quality
Assurance Project Plan developed under EPA protocols
and reviewed and approved by EPA Quality Assurance
Management staff.
2) All data were collected in accordance with procedures
presented in an approved Sampling and Analysis Plan.
The Sampling and Analysis Plan was developed in accor-
dance with EPA Region 9 guidance and were reviewed and
approved by EPA Quality Assurance Management staff.
3) Random sample splits were collected by Board staff to
confirm the validity of data generated by Intel and
KCIII.
4) Selected data was validated by the Department of Health
Services and found to be qualitatively and quantita-
tively acceptable.
5) There has been reasonable repeatability of the data
based on six years of monitoring.
18
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CENTRAL
Former water Mipply ••II,
prucn! u»r or condition unknown,
location approiimott
(from SCVWO rocords)
EXPLANATION
• Meriting well
• E*Tfoetmg well
A—A* Locution of geologic MCtion
15,000 r*
iv.---.st:-cr*c J'37:
KIFER
ROAD
Figure 5.1
Well end Geologic Cross*Section Location Map
19
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N
Location •( InMl IU|MCIci
yw.^...M.»... / *•
-"? "•">/£/
Former Location of
Micro Scor«(« Corporatlcn
• "J"t"
* •» • **•»•..»• ••**••••••••
• - MONtTONMA WILL
O - IXTftACTION WILL
• . rHOPOMO OTWACTIOH Wilt
. PNOPIATY •OUNOAftV
.V. LOWNEY 4 ASSOCIATES
2«86 OADtEAO VtLUCC COOtT
-------
TABLE 5.3
CONCENTRATIONS OF CHEMICALS DETECTED IN GROUNOWATER SAMPLES
A-ZONE
MICRO STORAGE/INTEL MAGNETICS
SANTA CLARA, CALIFORNIA
CHEMICAL
GEOMETRIC
• MEAN**
(pg/litef)
MAXIMUM
CONC.
(pg/iiter)
FREQUENCY
OF
DETECTION
LOCATION
OF
MAXIMUM
Bromodiehloromethane
Chloroform
1,1-DichIoroethane
1,2-DichIoroethane
1,1 -Dichloroethene
1,2-Dichloroethene (trans)
1,2-Dichloroethene (cis/trans)
Difluoromethane
Ethylbenzene
Freon (Freon 113 & Freon 11)
Freon 11
Freon 12
Freon 13
Freon 113
Freon 123
Methylene chloride
Tetrachloroethene
Toluene
1,1,1 -Trichloroethane
1,1,2-Trichloroethane
Trichloroethene
NA
0.50
1.2
1.8
4.6
B.4
3.6
NA
NA
51
NA
NA
NA
53
3.1
22
1.4
6.4
15
0.20
32
23.
3.7
22
18
46
34
69
1.3
1.1
8,200
7.9
2.8
3.400
1,300
50
90
28
29
570
0.50
770
1/1
11/11
141/255
8/241
151/257
2/5
130/251
1/1
1/11
160/242
1/14
1/1
1/2
6/6
79/79
3/17
40/48
2/11
198/258
2/16
169/256
IM-E2
IM-E1
IM-6
IM-5
IM-11
MW-4
IM-11
IM-10
MW-2
IM-10
IM-10
IM-E2
MW-3
MW-3
IM-2
IM-E1
MW-3
MW-3
MW-3
IM-10
IM-11
* Geometric mean of detects only.
* NA « Geometric mean not calculated when chemical detected once.
All values are rounded to two significant figures.
21
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6.0 SUMMARY OF SITE RISKS
6.1 CONTAMINANT IDENTIFICATION
Twelve chemicals of potential concern were identified within
the Study Area. The twelve chemicals are as follows:
chloroform
1,1-dichloroethane (1,1-DCA)
cis 1,2-dichloroethene (cis 1,2-DCE)
trans 1,2-dichloroethene (trans 1,2-DCE)
1,1 dichloroethene (1,1-DCE)
l,l,2-trichloro-l,2,2-trifluroethane (Freon 113)
methylene chloride
tetrachloroethylene (PCE)
toluene
1,1,1-trichloroethane (1,1,1-TCA)
1,1,2-trichloroethane (1,1,2-TCA)
trichloroethylene (TCE)
The reasons for selecting the listed chemicals as indicator
chemicals are as follows:
1. Each of the indicator chemicals was consistently detected in
the samples throughout the plume area. Table 6.1 lists
detection freqencies for these compounds.
2. Each of the indicator chemicals possesses physiochemical
properties (relatively high water solubility and relatively
low soil sorption) which tend to promote their dispersion in
ground water. Toluene has a relatively low soil sorption
coefficient, therefore, has the potential to leach from soil
into ground-water. In addition, they are all quite volatile
and can easily escape into soil gas or the atmosphere.
Table 6.2 provides physical/chemical properties for the
chemicals of concern.
3. Most of the indicator chemicals are potential carcinogens.
TCE, PCE and 1,1-DCA were identified by EPA as probable
human carcinogens (Group B2) based on available laboratory
animal data. 1,1-DCE was identified by EPA as a possible
human carcinogen (Group C) based on available laboratory
animal data. TCA remains unclassified as a potential car-
cinogen because there is inadequate evidence of its car-
cinogenicity in animal studies. Freon 113 and cis 1,2-DCE
are noncarcinogens.
22
-------
4. The 1,1-DCA is a potential breakdown product of the major
plume contaminant, 1,1,1-TCA. The most common plume con-
taminant, TCE, breaks down into DCE and ultimately vinyl
chloride which has not been detected at this site.
EXPOSURE ASSESSMENT
Potential environmental pathways include those related to
contaminated groundwater. Potential human exposures to con-
taminants include ingestion of and direct contact with
groundwater, and inhalation of volatilized contaminants during
showering by area residents. Residential areas are located 1200
feet south of the site and 6000 feet north-northeast of the site.
Table 6.3 and 6.4 provide a summary of the human exposure path-
ways under current and future use conditions.
The primary route of exposure is to people working at or
near the facility. Currently, chemicals in the groundwater do
not contact human or environmental receptors. There are no sur-
face water bodies in the immediate vicinity of the facility, and
there are no drinking water supply wells within or near the Micro
Storage/Intel Magnetics facility. A municipal water system sup-
plies water to businesses and residents. Future exposure could
only occur during excavation of the site or if a shallow drinking
water well was installed.
TOXICITY ASSESSMENT
Reference doses (RfDs) have been developed by EPA for in-
dicating the potential for adverse health effects from exposure
to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals. Es-
timated intakes of chemicals from environmental media (e.g., the
amount of a chemical ingested from contaminated drinking water)
can be compared to the RfD. RfDs are derived from human
epidemiological studies or animal studies to which uncertainty
factors have been applied (e.g., to account for the use of animal
data to predict effects on humans). These uncertainty factors
help ensure that the RfDs will not underestimate the potential
for adverse noncarcinogenic effects to occur.
Cancer potency factors (CPFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating excess lifetime can-
cer risks associated with exposure to potentially carcinogenic
chemicals. CPFs, which are expressed in units of (mg/kg-day)""1,
are multiplied by the estimated intake of a potential carcinogen,
in mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the CPF. Use of this approach makes
23
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underestimation of the actual cancer risk highly unlikely. Can-
cer potency factors are derived from the results of human
epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been
applied.
EPA also assigns weight-of-evidence classifications to
potential carcinogens. Under this system, chemicals are clas-
sified as either Group A, Group Bl, Group B2, Group C, Group D,
or Group E. Group A chemicals (known human carcinogens) are
agents for which there is sufficient evidence to support the
causal association between exposure to the agents in humans and
cancer. Groups Bl and B2 chemicals (probable human carcinogens)
are agents for which there is limited (Bl), or inadequate (B2)
evidence of carcinogenicity from human studies, but for which
there is sufficient evidence of carcinogenicity from animal
studies. Group C chemicals (possible human carcinogens) are
agents for which there is limited evidence of carcinogenicity in
animals, and Group D chemicals (not classified as to human car-
cinogenicity) are agents with inadequate human and animal
evidence of carcinogenicity or for which no data are available.
Group E chemicals (evidence of noncarcinogenicity in humans) are
agents for which there is no evidence of carcinogenicity in ade-
quate human or animal studies. Several of the chemicals of con-
cern at the MSC/IM site have been classified in Group B2
(chloroform, 1,1-DCA, methylene chloride, tetrachloroethene, and
trichloroethene) and benzene has been classified in Group A.
Tables 6.5 and 6.6 contain reference doses, cancer potency
factors, and weight of evidence for site chemicals.
6.2 RISK CHARACTERIZATION
~ >&
A Baseline Public Health Evaluation (BPHE) dated May 1,
1990, was prepared by Clement Associates Inc. under contract to
the Board. The BPHE was conducted to evaluate current and poten-
tial future health risks posed by the combined MSC/IM site.
Since the shallow zone groundwater from beneath the combined
MSC/IM site is not currently used for drinking water supply, no
current risk was identified at the combined MSC/IM site. Poten-
tial future health risks are based on exposures that could occur
in the future if untreated shallow zone groundwater was used for
human consumption and residential development occurred on the
combined MSC/IM site. To ensure that human health is protected,
the BPHE incorporated conservative assumptions. Therefore, it is
unlikely that the actual risks posed by the combined MSC/IM site
in the future would be greater than estimated. Average case and
maximum case scenarios are presented in the BPHE. The informa-
tion below refers to the maximum case scenarios using a 30 year
exposure duration.
Excess lifetime cancer risks are determined by multiplying
the intake level with the cancer potency factor. These risks are
probabilities that are generally expressed in scientific
24
-------
notation(e.g., l x 10~6 or 1E-6). An excess lifetime cancer risk
of i x 10~6 indicates that, as a plausible upper bound, an in-
dividual has a one in one million chance of developing cancer as
a result of site-related exposure to a carcinogen over a 70-year
lifetime under the specific exposure conditions at a site.
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard
quotient (HQ) (or the ratio of the estimated intake derived from
the contaminant concentration in a given medium to the
contaminant's reference dose). By adding the HQs for all con-
taminants within a medium or across all media to which a given
population may reasonably be exposed, the Hazard Index (HI) can
be generated. The HI provides a useful reference point for gaug-
ing the potential significance of multiple contaminant exposures
within a single medium or across media.
Using the above hypothetical scenario of future groundwater
use, the carcinogenic risk from ingestion and inhalation of VOCs
at the MSC/IM site is l x 10~. A carcinogenic risk of 1 x 10~3
is equal to one excess occurrence of cancer in a population of
1000. EPA's acceptable carcinogenic risk range for cleanup stan-
dards selected for a site is 10"~4 (l in 10,000) to 10~6 (1 in
1,000,000).
Using the same scenario, the noncarcinogenic Hazard Index
for ingestion and inhalation of VOCs from the use of shallow
groundwater is 5.0. If the noncarcinogenic Hazard Index is less
than one, EPA considers the combined intake of chemicals unlikely
to pose a health risk. Table 6.7 provides calculations of risks
associated with the future-use scenario.
Thus the carcinogenic risk and Hazard Index associated with
a "no action" remedy exceed EPA's acceptable carcinogenic risk
and Hazard Index range. Table 6.8 provides the calculation of
the carcinogenic risk based on clean-up standards, and Table 6.9
depicts the hazard index for noncarcinogens.
The carcinogenic risk at the cleanup standards (chemicals
listed on Table 6.8) associated with the potential future use
scenario of groundwater ingestion and inhalation of VOCs from
groundwater, using the maximum exposure scenario is 1 x 10~ . In
cleaning up TCE to the 5 ppb cleanup standard it is quite likely
that the concentrations of other VOCs will be reduced to levels
below the 5 ppb ranged The carcinogenic risk for TCE alone is 1.5
x 10~ . These risks were calculated using a potential future use
scenario with a 30 year duration exposure per EPA guidance.
The noncarcinogen Hazard Index associated with the cleanup
standards is 0.38. The selected remedy is protective of human
health and the environment — as required by Section 121 of
CERCLA — in that pollution in groundwater is treated to at least
MCLs and falls within EPA's acceptable carcinogenic risk range
(10~6 to 10 ) and noncarcinogenic Hazard Index of less than one.
25
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As shown on Table 4.1, the groundwater cleanup standards for
all contaminants, except 1,1 DCE are Federal or State (MCLs),
either adopted or proposed, whichever is more stringent. The
cleanup standard for 1,1 DCE is less than its proposed or adopted
MCLs. This reduction was necessary so that the cumulative risk
associated with the cleanup standards would be within acceptable
levels. The final cleanup standards for the suite of chemicals
detected in the shallow zone equate to a future use scenario car-
cinogenic risk level for groundwater ingestion and inhalation of
VOCs of 1 x 10~4
6.3 PRESENCE OF SENSITIVE HUMAN POPULATIONS
In order for a chemical to pose a human health risk, a com-
plete exposure pathway must be identified. The greatest poten-
tial for exposure to chemicals at the site would be from residen-
tial uses. The BPHE did not identify potential exposure pathways
under current land use conditions and did not identify sensitive
human populations. The closest residences are approximately
one-half mile to the south and one mile to the northwest. Al-
though several elementary schools are included in each of these
residential areas, the closest school is Bracher Elementary
School (grades K-5, approximately 440 students) which is located
at 2700 Chromite Drive. There are no day care centers or con-
valescent homes located in the immediate vicinity of the site.
6.4 PRESENCE OF SENSITIVE ECOLOGICAL SYSTEMS
Two endangered species are reported to use South San Fran-
cisco Bay, located approximately 11 miles northwest 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 oc-
casionally seen in the Bay Area, but does not nest in the South
Bay. Ranges of the endangered American peregrine falcon and
southern bald eagle include the Bay Area. The southern bald
eagle does not use bay and bayshore habitats, but the perigrine
falcon has started to make a comeback at some northern locations
in San Francisco Bay.
The combined MSC/IM site is located near the geographic cen-
ter of the City of Santa Clara, in a commercial-light industrial
setting. No parks or surface water are adjacent to the site, and
over 80% of the property is covered with blacktop or a building
slab. Chemical constituents are only present in the shallow
groundwater. Therefore, the Study Area does not constitute
critical habitat for endangered species nor does it include or
impact any "wetlands."
26
-------
6.5 CONCLUSION
Actual or threatened releases of hazardous substances from
the Micro Storage/Intel Magnetics Superfund site, if not ad-
dressed 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 ex-
posure pathways exist, EPA has determined that remediation is
warranted.
27
-------
TABLE €-1
SELECTION OF CHEMICALS OF POTENTIAL CONCERN FOR ORGANIC CHEMICALS IN QROUNDWATER
MICRO STORAGE/INTEL MAGNETICS
SANTA CLARA, CALIFORNIA
CHEMICAL
Bromodichloromethane
Chloroform
1,1-Dlchkxoethane
1,2-Dlchloroethane
1,1-Dlchloroethene
1,2-Dlchloroethene (trans)
1,2-Dlchloroethene (cis/lrans)
Dlfluoromethane
Ethylbenzene
Freon (Freon 113 & Freon 11)
Freon 11
Freon 12
Freon 13
Freon 113
Freon 123
Methylene chloride
Tetrachloroethene
Toluene
1,1.1-Trtchloroethane
1,1,2-Trlchtoroeihane
Trichloroethene
FREQUENCY
OF DETECTION
1/1
11/11
141/255
8/241
151/257
2/5
130/251
1/1
1/11
160/242
1/14
1/1
1/2
6/6
79/79
3/17
40/48
2/11
198/258
2/16
169/256
MAXIMUM
CONCENTRATION
frg/liter)
(
2.2
3.7
22
18
46
34
69
1.3
1.1
8,200
7.9
2.8
3,400
1,300
50
90
28
29
570
0.50
770
SELECTED
(WN)
N
Y
Y
N
Y
Y
Y
N
N
Y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
COMMENT
Professional Judgement
Potential carcinogen
Frequency > 5%
Frequency < 5%
Frequency > 5%
1,2-Dlchloroethene (ds/trans) selected
Frequency > 5%
Professional Judgement
Professional Judgement
Frequency > 5%
Freon selected
Professional Judgement
Professional Judgement
Freon selected
Frequency > 5%
Potential carcinogen
Frequency > 5%
Used In on-she processes
Frequency > 5%
Potential carcinogen
Frequency > 5%
00
(N
-------
Phyilcal/Chmlcal Properties of the Organic Cheeiicais of potential concern
Molecular Water
Weight Solubility Sol.
(g/anl) (a«/l) Raf.
Chlorinated aliphatic hydrocarbons
Chlorofona
1,1-Olchloroethane
1,1-Oichloroethene
1,2-Olchlorotthent (els)
1,2-Dlchlo'roethena (trans)
freon 11
freon 113
freon 123
Methylent chloride
Tetrechloroethene
1,2,4-Trlchlorobenztnt
1.1,1-Trichtoroethant
1,1,2-Trlchlorotthant
Trichlorotthene
Nonocycllc aroMtic hydrocarbons
lenient
Toluene
119.0 8.200
98.
96.
96.
96.
137.
187.
NA
84.
165.
181.
133.
133.
131.
SJ.OOO
2,250
3.500
6.300
t. too
170
NA
20.000
150
30
1.330
4.500
1.100
78.0 1,750
92.2 535
A
1
At
AC
J
N
K
NA
N
G
AA
Q
U
G
1
G
Vapor
Pressure
(MNg)
1.51E«02
1.82E«03
S.91E«02
2.08E«02
3.24E02
6.67E«02
2.70E«02
NA
3.62E«02
t.78E«Ot
2.VOE-01
1.23E+02
3.00E«01
5.79E«OI
9.S2E+01
2.81E*01
VP
Ref.
,
1
G
AC
J
H
G
NA
N
P
H
0
W
C
t
U
Henry's law
Constant
le
3.80E-03
5.70E-03
1.50E-01
6.60E-03
6.56E-03
S.ME«02
3.90C-01
NA
2.60E-03
2.IOE-02
2.31E-03
2.80E-02
1.20E-03
8.90E-03
5.59E-03
6.60E-03
HI
) Ref.
C
C
C
C
C
R
V
NA
C
C
R
C
C
C
C
C
•-Partition Coefficients--
Soil Organic Octanol- log
Carbon Koc Water KOM
(log Koc) Ref. (log Kou) Ref.
1.49
0.48
1.81
1.77
1.77
2.20
2.41
NA
0.94
2.56
3.96
2.18
1.74
2.10
1.92
2.48
0
N
H
N
H
H
0
NA
H
N
N
H
H
N
0
H
1.97
1.79
1.84
2.06
2.09
2.53
2.00
NA
1.30
2.60
4.30
2.50
2.47
2.38
2.12
2.73
E
1
AB
K
1C
S
G
NA
0
P
AA
H
W
E
t
U
Density
1.48
1.18
1.22
1.23
1.23
NA
1.50
NA
t.33
1.62
1.46
1.34
NA
1.46
0.88
0.89
Oens.
Ref.
f
G
I
I
I
NA
C
NA
I
G
f
I
NA
I
I
I
NA: Not Available
SOURCES fOR PHYSICAL/CHEMICAL PROPERTIES ARE ON THE NEXT PACE
-------
TABLE 6-3
HUMAN EXPOSURE PATHWAYS FOR MICRO STORAGE/INTEL MAGNETICS
UNDER CURRENT-USE CONDITIONS
Environmental
Media
Exposure
Point
Potential
Receptors
Route ol
Exposure
Pathway Complete?
Surface Soil
Groundwater
MS/IM Site
MS/IM Site
None
None
Direct contact, and
inhalation of airborne
partteulaies.
Ingestlon, and Inhalation
of volatile chemicals
released from
groundwaten during
indoor use.
No. The site is currently paved. Therefore,
direct contact with contaminated soils and
generation of airborne particulates are
unlikely. Not evaluated at MS/IM site.
No. Shallow groundwater in the A- and B-
zones Is not used for drinking. Not
evaluated at MS/IM site.
Surface Water
Calabazas Creek None
Direct contact with
contaminated surface
waters.
No. Intel releases its treated effluent under
an NPDES permit to a storm drain which
discharges to the Calabazas Creek. Since
this is a permitted release, it is outside the
scope of this assessment. Not evaluated at
MS/IM site.
Table continued on next page.
-------
TABLE 6-3 (CONTINUED)
HUMAN EXPOSURE PATHWAYS FOR MICRO STORAGE/INTEL MAGNETICS
UNDER CURRENT-USE CONDITIONS
Environmental Exposure Potential Route of Pathway Complete?
Media Point Receptors Exposure
Air Off-Site None Inhalation of volatile No. The groundwater plume In the A-zone
Residences chemicals released from extends off the site predominantly beneath
groundwater. pavement and Industrial buildings. The
plume does not extend beneath residences
and, therefore, will not be evaluated at
MS/1M site.
Air Off-She None Inhalation of volatile No. If volatUe organic chemicals volatilized
Residences chemicals released from from on-stte subsurface soils on site, it is
subsurface soils. unlikely that detectable concentrations would
be contained In ambient air of off-site
residents located 0.5 to 1 mile from the
MS/IMsrte.
-------
6-4
HUMAN EXPOSURE PATHWAYS FOR MICRO STORAGE/INTEL MAGNETICS
UNDER FUTURE-USE CONDITIONS
Environmental
Media
Exposure
Point
Potential
Receptors
Route of
Exposure
Pathway, Complele?
Surface Soil
MS/1M Site
Qroundwater
Air
Surface Water
MS/1M Site
MS/IM Site
None
On-Site
Residents
Direct Contact.
On-Site
Residents
On-Stte
Residents
On-Site
Residents
Ingesllon. Inhalation
from Indoor uses of
groundwater.
Inhalation of volatile
chemicals released from
subsurface soils and
groundwaler.
Direct contact with
contaminated surface
waters.
Yes. Inorganics and semi-volatile organlcs
may persist In soils but inadequate data are
available to quantitatively evaluate pathways.
Volatile organic chemicals are not
anticipated to have a long residence lime in
surface soils. Not evaluated at MS/IM site.
Yes. Groundwater In the A- and B-zones
underlying the MS/IM site may be used in
the future for drinking water and other
domestic uses. Evaluated at MS/IM site.
Yes. Volatile organic chemicals may be
released from subsurface soils and
groundwater and may migrate into on-site
residences. Evaluated at MS/IM site.
.No. Releases to surface water are not
anticipated to occur in the future. Not
evaluated at MS/IM site.
-------
MICRO STORAGE/INTEL MAGNETICS
SANTA CLARA. CALIFORNIA
Chemical
RID (mg/kg/day)
(Uncertainty Factor]8
Cancer Potency
Factor (mg/kg/day)*1
EPA Weight
of Evidence5
Source6
Benzene
Chloroform
1,1-Dlchloroethane
1,1-Dlchloroethene
cls-1 ,2-Dichloroethene
trans- 1 ,2-Dlchloroethene
Freon 11
Freon113 '
Freon 123
Methylene chloride
Tetracrrioroetnene
Toluene
1,1,1-Trichloroethane
1,1,2-Trlchloroethane
1 ,2,3-Tr Ichlorobenzene
1 ,2,4-Trichlorobenzene
Trlchloroeihene
a
1 x 10*2
1 x KT1
9 x 10*3
1 x 10'2
2 x 10*
3 x 10*f
3 x 10*
~
6 x 10'2
1 X 10'2
3 X 10*1
9 x 10'2
4 X 1(T3
—
2x«T2
7.4 X 10'3
11000]
(1000)
[1000]
jioooj
[1000]
(1000]
(10J
(100]
(1000]
(100]
(1000]
[1000]
(1000)
[1000]
2.9 X 10"'
6.1 X 10'3
9.1 X 10'2
6.0 x 10'1
-
—
—
-
_
7.5 X ID"3
5.1 X 10'* °
—
—
5.7 X 10'2
_.
A
1.1 X 10'z
A
B2
B2
C
-
-
-
-
—
B2
B2
~.
-
C
..
D
B2
IRIS
IRIS
HEA
IRIS
HA. 3/31/87
IRIS
HEA
IRIS
_
IRIS
IRIS, HEA
IRIS
IRIS
IRIS
_
IRIS
HA, 3/31/67, HEA
ro
ro
fl Uncertainty factors used to develop reference doses consist of multiples of 10, each factor representing a specific area of uncertainty inherent in the
data available. The standard uncertainty factors Include:
. a ten-fold factor to account for the variation in sensitivity among the members of the human population;
. a ten-fold factor to account for the uncertainty In extrapolating animal data to the case of humans;
. a ten-fold factor to account for the uncertainty In extrapolating from less than, chronic NOELs to chronic NOAELs; and
. a ten-fold factor to account for uncertainty in extrapolating from LOAELs to NOAELs.
0 Weight of evidence classification schemes tor carcinogens: A - Human Carcinogen, sufficient evidence from human epidemlologlcal studies;
B1 • Probable Human Carcinogen, limited evidence from epidemtologfcal studies and adequate evidence from animal studies; B2 • Probable Human
Carcinogen, Inadequate evidence from epklemiotogical studies and adequate evidence from animal studies; C - Possible Human Carcinogen, limited
evidence in animals in the absence of human data; 0 - Not Classified as to human carcinogenicity; and E • Evidence of Noncarcinogenicity.
c Sources: IRIS • Integrated Risk Information System; HEA • Health Effects Assessment Summary Tables; HA - Health Advisory.
d Pending review by EPA.
-------
MICRO STORAGE/INTEL MAGNETICS
SANTA CLARA, CALIFORNIA
Chemical
Benzene
Chloroform
1,1-Dichloroelhano
1,1-Dtehloroethene
cls-1 ,2-Dlchloroethene
trans-1 ,2-Dfchloroethene
Freon 11
Freon 113'
Freon 123
Methylene chloride
Tetrachloroelhene
Toluene
1,1,1-Trichloroethane
1 ,1.2-Trfchloroelhane
1 ,2,3-Trichlorobenzene
1 ,2,4-Trichlorobenzene
Trichloroethene
RID (mg/kg/day)
(Uncertainty Factor]8
mm
M
1.0 XlO"1 (1000)
-
-
—
2.0 x 10*1 (10000)
~
M
B.6 X 10*ld
_
5.7x10*ld(100)
3.0x10-' (1000)
~
_.
3.0 x 10*3 (1000)
-
Cancer Potency
Factor (mg/kg/day)*'
2.9 x 10'2
8.1 x 10'2
1.2
-
_
~
-
».
1.4X10*2
3.3X10*36
A
5.7 X 10'Z
„
4*
1.3 X 10'Z
EPA Weight
of Evidence"
A
B2
C
-
-
-
—
^
B2
B2
-
C
*.
.-
B2
Source0
IRIS
IRIS
HEA
IRIS
—
..
HEA
~
..
HEA, IRIS
HEA
HEA
HEA
IRIS
..
HEA
IRIS6
8 Uncertainty factors used to develop reference doses consist of multiples of 10, each factor representing a specific area of uncertainty inherent in the
data available. The standard uncertainty factors include:
. a ten-fold factor to account for the variation In sensitivity among the members of the human population;
. a ten-fold factor to account for the uncertainly In extrapolating animal data to the case of humans;
. a ten-fold factor to account for the uncertainty In extrapolating from less than chronic NOEL to chronic NOAELs; and
. a ten-fold factor to account for uncertainty in extrapolating from LOAELS to NOAELs.
0 Weight of evidence classification schemes for carcinogens: A - Human Carcinogen, sufficient evidence from human epidemiological studies;
B1 - Probable Human Carcinogen, limited evidence from epidemiological studies and adequate evidence from animal studies; B2 - Probable Human
Carcinogen, inadequate evidence from epidemiological studies and adequate evidence from animal studies; C • Possible Human Carcinogen, limited
evidence in animals in the absence of human data; D - Not Classified as to human carcinogenicity; and E - Evidence of Noncarcinogenicity.
c Sources: IRIS - Integrated Risk Information System; HEA - Health Effects Assessment; HA - Health Advisory.
<• Converted from units of mg/m , assuming that an average adult weighs 70 kg and respires at an average rate of 20 m3 air per day.
0 Pending review by EPA.
-------
FuturfUie scenario:
Chronic Dally Intake* and Potential Ricks due to
Ingestion of Grounduater and Inhalation of Volatile!
A-Zone
MICRO SIORAGE/IMTEl MAGNETICS
A. POTENTIAL CARCIHOCENS
ESTIMATED EXPOSURE
POINT
CONCENTRATIONS (og/l)
Chealcal
i
•ensene <•)
Chloroform
1,1-Dlchloroethene
t.VDIchloroethtno
Methylene chloride
Tetrachtoroethene
1, 1,2-TrlcMoroethene
Trlchloroethene
AVERAGE
2.4
0.50
1.2
4.6
22
1.4
0.20
32
MAXIMUM
2.4
5.7
22
46
90
28
0.50
770
CHRONIC DAILY INTAKE (COI)
FOR INGESTION
n
2E-OS
7E-04
Table continued on next page.
-------
J p w f \ ww»l »*••«*»--- /
tu\ tie Scenario:
Chronic Dally Intake* and Potential Risks due to
Ingestlon of Grounduater and Inhalation of Volatltes
A'Zone
HICRO STORAGE/INTEL MAGNETICS
B. NOHCARCINOGEMS
ESTIMATED EXPOSURE
POINT
CONCENTRATIONS (ug/L)
AVERAGE PLAUSIBLE
Chemical
Chloroform
1,1-Dlchloroethano
1,1-Dlchloroathene
1,2-Dlchloroethene (els/trans) (b)
tr»ns-1,2-Dlchloroeth*n*
Freon 113 (c)
Methyl en* chloride
Tetrachloroethene
Toluene
1,1,1-Trlchloroethane
1.1,2-Trlchloroethane
Trlchloroethene
MAXIMUM
0.50
1.2
4.6
3.6
8.4
54
22
1.4
6.4
15
0.20
32
3.7
22
46
69
34
8200
90
28
29
570
0.50
770
CHRONIC DAILY INTAKE (COI)
FOR INGESTION
(av/kg/day)
AVERAGE * PLAUSIBLE
MAXIMUM
1.4E-05
3.4E-OS
1.3E-04
1.0E-04
2.4E-04
T.SE-03
6.3E-04
4.0E-05
1.8E-04
4.3E-04
5.7E-06
9.1E-04
.1E-04
.3E-04
.3E-03
.OC-03
.7E-04
.3E-01
.6E-03
.OE-04
.3E-04
.6E-02
.4E-05
.2E-02
HAZARD INDEX
COItRfD RATIO
(INGESTION)
AVERAGE
1E-03
3E-04
1E-02
5E-03
1E-02
5E-05
1E-02
4E-03
6E-04
5E-03
1E-03
1E-01
2E-01
PLAUSIBLE
MAXIMUM
1E-02
6E-03
1E-01
1E-01
SE-02
8C-03
4E-02
8E-02
3E-03
2E-01
4E-03
3E«00
4E»00
CDI.-RID RATIO
(INHALATION)
AVERAGE PLAUSIBLE
MAXIMUM
• • • *
3E-04 6E-03
..
..
-.
BE -03 1E*00
7E-04 3E-03
..
3E-04 1E-03
IE -03 SE-02
• * * *
..
1E-02 1E*00
vo
•- - Mo Inhalation toxlclty criteria were available for these chewtlcals.
(a) • Eatisuted grounduatcr concentration assualng eojullibriua with a soil concentration of 2 ug/kg. See Appendix A for details.
(b) • Thla value Is the su* of the non-speclated 1,2-dlchloroethene and the trans-1.2-dlchloroethene.
(c) • freon Is a conbinatlon of freon 113 (reported on a confcination of Freon 11 and freon 113) and freon 123.
-------
Chemical
Benzene
1,1 Dichloroelhane
1,1 Dichloroethenc
Melhylene Chloride
Teuachloroelhene
Trichloroelhene
It
Cleanup Standard
, mg/1
1.0x10'* •
5.0xlO» •
4.0xlO»
5.0xlO»
5.0x10*
5.0x10*
\SLE 6-8 pctermination of Excess Lifetime Carcinogens
Risk Based on Clean-Up Standard,
2986 and ^000 Oakmead Villace Court.
Chronic Daily
Intake
1.1x10-*
5.5x10*
4.4x10-*
5.5x10*
5.5x10*
5.5x10*
Santa Clara, California
Cancer Potency Factor
Oral
2.9xlOJ
9-lxlO'1
6.0x10-'
7.5x10*
5. 1x10 2
1.1x10-*
Oral
Risk
3- 19x10 7
5.00x10-*
2.64x10*
6.05xlO'7
2.81x10*
6.05x10"
•
CPP
Inhale
2.9x10*
9. 1x10 l
1.2
1.4xlO»
3.3x10*
1.7xIO'2
Inhale
Risk
3.19xlO'7
5.00x10*
5.28x10 » .
7.70x10'
1.82xlO'7
9.35xl07
Risk
6.38xlO'7
1.00x10'*
7.92x10'*.
1.38x10^
2.99x10^
1.54x10*
Cancer Potency Factor (mg/kg/day)'1
Chronic Daily Intake (mg/kg/day) - Clean-up Sttrdard x 0.011
Risk-CDlxCPP
n
Toul Carinogen Risk - 9.57x10 *
-------
TABLE 6-9 Determination of Total Hazard Index.
fpr Non-Carcinogens Based on Clean-Up_5tand.ard$
2986 and 30QO Oakmead Village Court,
Santa Clara California *
i Cleanup Standard
Chemical MCL (mg/1)
1,1 Dichloroethane
1,1 Dichlorocthene
1,2 Dichloroethene (ds+trans)
Trans Dichloroethene
Frcon (Freon 113 + Picon 11)
Melhylene Chloride
Teuachloroethcne
Toluene
1,1,1 Trichloroethane
Trichloroethene
5.0x10-*
6.0x10-*
6.0x10*
1.0x10-*
1.2
5.0x10*
5.0x10'*
4.0x10*
2.0x10'
5.0x10*
Chronic Daily
Intake
1.45X10"4
1.74x10*
1.74X10-4
2.90x10^
3.48x10*
1.45x10-*
' 1.45x10^
1.16x10-*
5.80x10*
1.45xlO<
Reference Dose
Oral
1.0x10'
9.0x10* *
3.0x10-*
2.0x10*
30.3
6.0x10*
1.0x10*
2.0x10'
9.0x10*
7.4x10'*
Oral
Hazard Index
1.00x10-*
1.93x10*
5.80x10*
1.45x10*
1.15x10*
2.40x10*
1.45x10*
5.80x10*
6.40x10'*
1.96x10* .
Reference Dose
Inhale
1.0x10'
NA
NA
NA
2.0x10'
NA
NA
5.7x10'
3.0x10-'
NA
Inhale
Hazard Index
1.45x10*
NA
NA
NA
1.74x10-'
NA
NA
2.04x10*
1.93x10*
NA
Hazard Index
Oral & Inhale
2.90x10*
1.93x10*
5.80x10-*
1.45x10*
1.75x10'
2.40x10*
1.45x10*
5.80x10*
8.33x10*
1.96x10*
proposed Federal MCL
Reference Dose (mg/kg/Day)
Chronic Daily InUke (mg/kg/Day) • Cleanup Sundard x 0.029
Hazard Index - CDI/RID
NA-Not Available
CO
Hazard Index < 1.0
-------
7.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS)
Under Section I21(d)(1) of CERCLA, remedial actions must at-
tain 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.
"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
appropriate" 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.
Table D-l depicts documentation of contaminant specific ARARs to
be met by the MSC/IM site.
39
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7.1 TYPES OF ARARS
There are three types of ARARs. The first type includes
"contaminant specific" requirements. These ARARs set limits on
concentrations of specific hazardous substance, contaminants, 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 in-
formation 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 AND TBCS
Section 1412 of the Safe Drinking Water Act. 42 U.S.C. Section
300a-l
Under Section 1412 of the Safe Drinking Water Act, EPA is
required to set Maximum Contaminant Levels Goals (MCLGs) for
ground and surface water. Under CERCLA, 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 in
ground water is the MCLG (if not equal to zero), the federal MCL,
or the State MCL, whichever is most stringent.
40
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State Board Resolution 88-63
On March 30, 1989, the Regional Board incorporated the State
Board Policy of "Sources of Drinking Water" into the Basin Plan.
The policy provides for a municipal and domestic supply designa-
tion for all waters of the State with some exceptions.
Groundwaters of the State are considered to be suitable or poten-
tially suitable for municipal or domestic supply with the excep-
tion of where: 1) the total dissolved solids in the groundwater
exceed 3000 mg/L, and/or 2) the water source does not provide
sufficient water to supply a single well capable of producing an
average, sustained yield of 200 gallons per day. Based on data
submitted by KCIII and Intel, the Regional Board has determined
that neither of these two exceptions apply to the A and B zones
at the combined MSC/IM site. Thus, the A and B zones at the com-
bined MSC/IM site are potential sources of drinking water under
state authority.
National Primary Drinking Water Standards. 40 CFR Part 141
Establishes primary maximum contaminant levels (MCLs) that
are health based standards for public water systems. MCLs are
ARARs for any water that is considered to be a source or poten-
tial source of drinking water. MCLs are applicable at the tap
when the water is directly provided to 25 or more people or 15 or
more service connections. Otherwise, MCLs are relevant and ap-
propriate .
California/s Resolution 68-16
On October 28, 1968, the State Water Resources Control Board
adopted Resolution No. 68-16, "Statement of Policy with Respect
to Maintaining High Quality Waters in California". This policy
calls for maintaining the existing high quality of State waters
unless it is demonstrated that any change would be consistent
with the maximum public benefit and not unreasonably affect
beneficial uses. The original discharge of waste to the
groundwater at the combined MSC/IM site was in violation of this
policy; therefore, the groundwater quality needs to be restored
to its original quality as determined by the cleanup standards in
Table 4.1.
7.3 ACTION SPECIFIC ARARS AND TBC8
California Department of Health Services Drinking Water Action
Levels fDWALs)
California Department of Health Services (DHS) DWALs are
health-based concentration limits set by the DHS to limit public
exposure to substances not yet regulated by promulgated stan-
41
-------
dards. They are advisory standards that apply at the tap for
public water supplies. The DWAL for toluene is 100 ppb. These
DWALs are not ARARs, but are "To Be Considereds" or TBCs. ARARs
with more stringent requirements take precedence over these
DWALs.
National Pollutant Discharge Elimination System (NPDES)
NPDES substantive permit requirements and/or RWQCB Waste
Discharge Requirements (WDRs) are potential ARARs for effluent
discharges. The effluent limitations and monitoring requirements
of an NPDES permit or WDRs legally apply to point source dis-
charges such as those from a treatment system with an outfall to
surface water or storm drains. The RWQCB established effluent
discharge limitations and permit requirements based on Water
Quality Standards set forth in the San Francisco Bay Regional
Basin Plan.
Safe Drinking Water Act. Underground Infection Control (UIC)
If treated ground water is injected, it must be done in com-
pliance with regulations for a Class V underground injection
well. These regulations are found in the 40 CFR 144, especially
144.13 (4) (c).
Resource Conservation Recovery Act (RCRA) Land Disposal
Restrictions
The contaminated ground water contains two spent solvents
that are RCRA listed wastes. TCE is an F001 listed waste, and
TCA is an F002 listed waste. Adsorbents and other materials used
for remediation of groundwater VOCs, such as activated carbon,
chemical-adsorbing resins, or other materials used in the treat-
ment of ground water or air will contain 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.
Preparedness and Prevention. 40 CFR 264.30. et seq. Subpart C
Applicable for on-site treatment, storage or disposal of hazard-
ous waste.
Contingency Plan and Emergency Procedures 40 CFR 264.50 et seq.
Subpart D
Applicable for on-site treatment, storage or disposal of hazard-
ous waste.
Manifest System. Recordkeepina. and Reporting 40 CFR 264.70
et.sea. Subpart E.
42
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Applicable when waste is transported for off-site treatment,
storage, or disposal.
Occupational Safety and Health Act. 29 U.S.C. Section 651-678
Regulates worker health and safety. Applies to all response ac-
tivities under the NCP.
Hazardous Material Transportation Act. 49 U.S.C. Sections 1801-
1813
Hazardous Materials Transportation Regulations 49 CFR Parts 107.
171-177
Regulates transportation of hazardous materials. Applicable when
carbon canisters are shipped off-site.
7.4 LOCATION-SPECIFIC ARABS
Fish and Wildlife Coordination Act
The Fish and Wildlife Coordination Act is an applicable re-
quirement for the locations adjacent to Calabazas Creek and other
tributary streams and marshes.
43
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TABLE D-l. Ppcumentatlon of ARARs.
2986 and 3000 Oakmead Village Court,.
Santa Clara. California
Chemical
Specific
ARARa
TCB
Freon 113
1,1 DCI!
Total 1,2 DCU
Trans 1,2 OCB
Benzene
1,1 DCA
Alternative I
flp Action
5(ig/l California MCL
and site specific standard
may be met in several
decades or longer.
1,200 |ig/l California MCL
and site specific standard
may be met in several
decades or longer.
4 |ig/l site specific
standard may be
met in several
decades or longer.
6 Mg/1 California MCL
and site specific standard
may be met in several
decades or longer.
10 Mg/1 California MCL
and site specific standard
may be met in several
decades or longer.
1 Mg/1 California MCL
and site specific standard
have been met
5 |ig/l California MCL
and site specific standard
have been met.
Alternative U
Institutional Controls
and Ground Water
SM8/I California Ma
and site specific standard
may be met In several
decades or longer.
1,200 Mg/1 California MCL
and site specific standard
may be met in several
decades or longer.
4 Mg/1 site specific
standard may be
met in several
decades or longer.
6 Mg/1 California MCL
and site specific standard
may be met in several
decades or longer.
10 Mg/1 California MCL
and site specific standard
may be met in several
decades or longer.
California MCL
and site specific standard
have been met.
5 Mg/1 California MCL
and site specific standard
have been met
Alternative 111
Ground Water
Extraction and
GAC Treatment
5Mg/l California MCL
and site specific standard
may be met in 10-12
years.
1,200 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
4 Mg/1 site specific
standard may be
met in 10
years or less.
6 Mg/1 California MCL
and site specific standard
may be met in 10-12
years.
10 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
1 Mg/1 California MCL
and site specific standard
have been met.
5 MB/I California MCL
and site specific standard
have been met.
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
5Mg/l California MCL
and site specific standard
may be met in 10-12
years.
1,200 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
4 Mg/1 site specific
standard may be
met in 10
years or less.
6 Mg/1 California MCL
and site specific standard
may be met In 10-12
years.
10 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
1 Mg/1 California MCL
and site specific standard
have been met
5 Mg/1 California MCL
and site specific standard
have been met.
Alternative V
Ground Water
Extraction and
Biological Treatment
5Mg/l California MCL
and site specific standard
may be met in 10-12
years.
1,200 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
4 Mg/1 site specific
standard may be
met in 10
years or less
6 Mg/1 California MCL
and site specific standard
may be met in 10-12
years.
10 Mg/1 California MCL
and site specific standard
may be met in 10
years or less.
1 Mg/1 California MCL
and site specific standard
have been met
5 Mg/1 California MCL
and site specific standard
have been met.
-------
TABLE Di. pocumentation of ARARs^
29R6 and 3000 Oakmead Village Court.
Santa Clarar California
(continued)
Chemical
Specific
ARAKs
PCE
Methylcnc
Chloride
Toluene
1 , 1 , 1 TCA
Alternative I
NO
5 Ug/l California MCL
and site specific standard
may be met in several
decades or longer.
5 fig/I site specific
standard has
been met.
1 G (\ig/\ California MCI
and site specific standard
have been met.
200 ug/l California MCL
and site specific standard
have been met.
Alternative II
Institutional Controls
and Ground Water
5 ug/1 California MCL
and site specific standard
may be met in several
decades or longer.
5 ug/1 site specific
standard has
been met.
100 Mg/l California MCL
and site specific standard
have been met.
200 Ug/1 California MCL
and site specific standard
have been met.
Alternative III
Ground Water
Extraction and
GAC Treatment
5 ug/l California MCL
and site specific standard
may be met in 10
years or less.
5 ug/l site specie
standard has
been met.
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
5 Ug/l California MCL
and site specific standard
may be met in 10
years or less.
5 ug/l site specific
standard has
been met.
Alternative V
Ground Water
Extraction and
Biological Treatment
5 ug/l California MCL
and site specific standard
may be met in 10
years or less.
5 Ug/l site specific
standard has
been met.
10 Oug/| California MCL 10 0 ng/| California MCL 10 fyg/J California MCL
and site specific standard and site specific standard and site specific standard
have been met. have been met. have been met.
200 Ug/l California MCL
and site specific standard
have been met.
200 Ug/l California MCL
and site specific standard
have been met.
200 Ug/l California MCL
and site specific standard
have been met.
m
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8.0 DESCRIPTIOH OF ALTERNATIVES
KCIII submitted a Remedial Investigation/Feasibility Study
dated January 9, 1991. The report contains the results of the
subsurface investigation, a description of the groundwater con-
tamination, and an evaluation of the interim cleanup actions,
remedial alternatives, and groundwater conservation measures.
EPA and the Regional Board staff determined that the technical
information contained in the RI/FS was acceptable for developing
a final cleanup plan; however EPA, and the Regional Board did not
accept all interpretations and recommendations contained in the
RI/FS. Specifically, EPA and Board staff disagreed with the por-
tions of the RI addressing the extent of the groundwater pollu-
tion along the northwest edge of the plume. EPA and Board staff
interpret the water quality data differently than is shown in the
RI. EPA and Board staff have addressed these issues in an Agency
Addendum to the RI, rather than in another revised version of the
RI. This Agency Addendum is included as Part IV of this ROD.
EPA and the Regional Water Quality Control Board evaluated
five remedial action alternatives for the Micro Storage/Intel
Magnetics site in accordance with CERCLA Section 121, the Na-
tional Contingency Plan ("NCP"), and the Interim Guidance on Su-
per fund Selection of Remedy. December 24, 1986 (Oswer Directive
No. 9355.0-19).
The Feasibility Study initially screened 21 remedial action
technologies. These technologies were screened based on im-
plementability, effectiveness, and cost criteria. The remedial
technologies that survived the screening were assembled into a
group of alternatives as follows:
Remedial Alternative 1
Remedial Alternative 1 is a "no further action" alternative,
retained for base-line comparison purposes in accordance with
CERCLA/SARA guidance. Remedial technologies are not implemented
at the combined MSC/IM site under this alternative. The existing
groundwater recovery treatment and discharge operation would
cease, as would any groundwater monitoring. The total present
worth cost of this alternative is negligible.
Remedial Alternative 2
Remedial Alternative 2 consists of the following:
Deed restriction
Groundwater monitoring
Total present worth cost = $46,000 to $73,000
46
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Remedial Alternative 3
Remedial Alternative 3 consists of the following:
Deed restriction
Groundwater monitoring
Groundwater extraction wells
Carbon adsorption treatment of extracted groundwater
Discharge of treated water to surface water under existing
NPDES permit
Total present worth cost = $630,000 to $1,100,000
Remedial Alternative 4
Remedial Alternative 4 consists of the following:
Deed restriction
Groundwater monitoring
Groundwater extraction wells
Oxidation/reduction treatment of extracted groundwater
Discharge of treated water to surface water under existing
NPDES permit
Total present worth cost = $1,600,000 to $3,600,000
Remedial Alternative 5
Remedial Alternative 5 consists of the following:
Deed restriction
Groundwater monitoring
Groundwater extraction wells
Biological treatment of extracted groundwater
Discharge of treated water to surface water under existing
NPDES permit
Total present worth cost = $1,000,000 to $1,300,000
47
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9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
This section provides an explanation 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.
Criteria
The alternatives were evaluated using nine component
criteria. These criteria, which are listed below, are derived
from requirements contained in the National Contingency Plan
(NCP) and CERCLA Sections 121(b) and 121(c).
The alternatives were evaluated in detail with respect to
the nine criteria in the FS report. A detailed analysis of the
alternatives was completed in the FS. A summary of this detailed
analysis is shown on Table 1.
1. Overall protection of human health and the environment.
This criterion addresses whether a remedy provides ade-
quate protection of human health and the environment.
2. Compliance with applicable or relevant and appropriate
requirements (ARARs). This criterion addresses whether
a remedy will meet all of the ARARs or other Federal
and State environmental laws.
3. Long-term effectiveness and permanence. This criterion
refers to expected residual risk and residual chemical
concentrations after cleanup standards have been met
and the ability of a remedy to maintain reliable
protection of human health and the environment over
time.
4. Reduction of toxicity, mobility or volume through
treatment. This criterion refers to the anticipated
performance of the treatment technologies a remedy may
employ.
5. Short-term effectiveness. This criterion addresses the
period of time needed to achieve cleanup and any ad-
verse impacts on human health and the environment that
may be posed during the construction and implementation
period, until cleanup standards are achieved.
6. Implementability. This criterion refers to the techni-
cal and administrative feasibility of a remedy.
7. Cost. This criterion includes estimated capital and
operation and maintenance, usually presented in a 30
year present worth format.
48
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8. Support Agency Acceptance This criterion addresses
EPA's acceptance of the selected remedy and any other
EPA comments.
9. Community Acceptance This criterion summarizes the
public's general response to the alternatives.
9.1 GROUND WATER
Threshold Criteria
Overall protection of human health and the environment
Alternatives 3, 4 and 5 would be protective of human
health and the environment. Alternatives 1 (the "no action"
alternative) and 2 (deed restriction with groundwater
monitoring) are not protective of human health and the en-
vironment, because it is expected that the groundwater plume
would continue to migrate, further degrading the aquifer.
Alternative 3 would provide the greatest protection.
Compliance with applicable or relevant and appropriate re—
quirements
Cleanup standards for this site are determined to be
the California Maximum Contaminant Levels and federal Maxi-
mum Contaminant Levels. Alternatives 3, 4, and 5 would meet
these ARARs within 10 - 12 years. Spent carbon canisters
will be disposed of in a manner that complies with federal
and state requirements, including RCRA. Table D-l in Sec-
tion 7 shows the contaminant cleanup standards to be
achieved.
Primary Balancing Criteria
Long-term effectiveness and permanence
Alternatives 3, 4, and 5 would mitigate any potential
future risks by preventing the migration of VOCs in
groundwater, and restoring the groundwater quality of the A
zone. Long-term monitoring, operation and maintenance would
be required. The long-term effectiveness and permanence is
anticipated to be achieved most effectively by implementing
Remedial Alternative 3.
Reduction of toxicity. mobility, or volume through treatment
Alternatives 3, 4, and 5 would reduce contaminants at
the site through extraction and treatment of contaminated
groundwater. Alternatives l and 2 would not result in a
49
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reduction of toxicity, mobility or volume since it relies on
natural attenuation mechanisms, such as dispersion, sorp-
tion, diffusion and degradation.
The existing system has proven to be effective in
reducing toxicity, mobility and volume of the groundwater
plume. However, Alternative 3 would be the most effective.
Because the Metropolitan Corporate Center plume and the
MSC/IM plume are in close proximity to each other, the Board
orders and EPA remedy will require that the operation of any
extraction system at the MCC and MSC/IM sites be done in a
coordinated effort. Both sites will be required to locate
extraction wells and select pumping rates that maximize con-
taminant removal and minimize the hydraulic effects on the
other site's groundwater plume.
Short-term effectiveness
Implementation of alternatives 3, 4, and 5 will provide
short-term effectiveness. Risks associated with groundwater
monitoring, recovery, treatment and discharge are mitigated
by the health and safety plan for the site, and by the fact
that no exposures to contaminants are anticipated.
Alternatives 1 and 2 will not be effective in contain-
ing the contaminant plume.
Implementability
Alternative 3 would utilize recovery and treatment sys-
tems which are already implemented at the site. Alternative
4 would utilize existing extraction wells but would require
that a new system be built to accomodate the oxidation/
reduction treatment of extracted groundwater. Alternative 5
would also utilize existing extraction wells and require
building of a new system for the biological treatment of ex-
tracted groundwater.
Alternatives l and 2 can be readily implemented at the
site as it involves discontinuing the current remedial ac-
tions.
The cost to implement Alternatives 1 and 2 would be
minimal in comparison to the other remedial alternatives for
the site. The existing wells would need to be plugged and
abandoned and the treatment system could be disassembled and
removed from the site.
The capital cost to implement Alternative 3 would be
low ($119,000) since the groundwater recovery, treatment,
and discharge systems are already in use at the site. The
system requires periodic maintenance to remain operable, and
50
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the carbon units must be replaced every eight months. The
present worth value ranges from $629,800 to $1,102,000 for
Alternative 3.
The capital cost to implement Alternative 4 would be
higher ($168,000), consisting mainly of costs associated
with custom manufacturing of a oxidation/reduction unit.
The present worth value of Alternative 4 ranges from
$1,554,400 to $3,613,800.
The capital cost to implement Alternative 5 consists of
conducting a pilot study, and manufacture of the bioreactor.
Alternative 5 has a present worth value that ranges from
$1,006,900 to $1,298,800.
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 alterna-
tive.
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
Remedy Selection Rationale and Statutory Determinations
The selected remedy is protective of human health and the
environment. Groundwater contamination is treated so that
the remaining potential future risks fall within the 10~4 to
10~6 carcinogenic risk range for acceptable cleanup stan-
dards. The remedy complies with ARARs by achieving cleanup
to at least Federal and State MCLs (proposed or adopted).
The selected remedy is effective in the short-term because
further plume migration is controlled by groundwater extrac-
tion. The selected remedy is effective in the long-term by
virtue of the fact that ARARs are achieved. Groundwater ex-
traction and treatment is a permanent solution and sig-
nificantly reduces pollutant toxicity, mobility and volume
at the combined MSC/IM site. The selected remedy is imple-
mentable.
Based on an evaluation of the alternatives, the selected
remedy for the combined MSC/IM site is Alternative No.3.
KCIII has estimated that it will take approximately 10 years
to achieve groundwater cleanup standards at a cost of
$630,000 to $1,100,000.
51
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The selected remedy consists of the following actions:
a. Continue groundwater extraction until cleanup standards
are achieved in all combined MSC/IM site monitoring
wells.
b. Install and sample a minimum of two new monitoring
wells; one well located midway along a line between
MMW-5 and the former location of IM-8, and one located
midway along a line between MMW-9 and MMW-7.
c. Hydraulic containment of the entire groundwater plume
above cleanup standards and continued groundwater ex-
traction at the four existing wells. Modifications to
the system are required in the event that the interim
hydraulic control system is demonstrated not to be ef-
fective in containing and removing the groundwater con-
taminants .
d. Maintenance of hydraulic control to prohibit the fur-
ther vertical and horizontal migration of the
groundwater pollution. This requirement shall remain
in effect until cleanup standards are achieved.
e. Continued quarterly groundwater monitoring at the com-
bined MSC/IM site during the cleanup period. Water
samples will continue to be collected to verify that
cleanup is proceeding and that there is no migration of
VOCs, above cleanup standard levels, beyond current
boundaries or into the deeper B zone. Detailed sam-
pling and reporting requirements for the combined
MSC/IM site are contained in the Self-Monitoring Plan
attached to the RWQCB Order No. 91-119.
f. Treatment of extracted groundwater with an existing
carbon adsorption system. The treated groundwater will
continue to be discharged to Calabazas Creek, under ex-
isting NPDES Permit No. CA0029670.
g. A deed restriction. MSC/IM shall be required to file a
deed restriction prohibiting use of on-site shallow
groundwater for drinking water and controlling other
subsurface activities. The deed restriction shall
remain in place until groundwater cleanup standards are
achieved.
52
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TABLE 1 Comparison of Alternatives.
1. Compliance with ARARi
- Chemkal Specific
Action Specific
• location Specific
2. Short Term Effectiveness
• Protection of Community
• Protection of Workers
•linvironmenlal Impacts
2986 and ^000 Oakmead Villace Court.
Alternative 1
No Action
Sapta Clara,
Alternative II
Institutional Controls
and Ground Water
California
Alternative III
Ground Water
Extraction and
GAG Treatment
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
Alternative V
Ground Water
Extraction and
Biological Treatment
Would lake several
decades or longer to
achieve clean-up
standards
No action
Not applicable
No additional risks.
Does not prevent the
use of the aliened
ground water
No additional risks
Discharge of impacted
ground water to nearby
creeks and/or Sl: Hay
unlikely. Current impact
probably negligible
Would take several
decades or longer to
achieve clean-up
standards
No action
Not applicable
No additional risks.
Prevents the use of
affected ground water
as a drinking water
source
No additional risks
Discharge of Impacted
ground water to nearby
creeks and/or SF May
unlikely. .Current impact
probably negligible
Would be achieved.
Clean-up standards likely
would be achieved in
approximately 10 to 12
years
Complies with surface
water discharge permit
requirements
Not applicable-
No additional risks.
The plume would be .
contained
No additional risks
'Che plume would be
contained. No impact
Would be achieved.
Clean-up standards likely
would be achieved in
approximately 10 to 12
years
Complies with surface-
water discharge permit
requirements; wastes
would be handled in
accordance wilh applicable
laws
Nut ajiplicable
No additional risks
The plume would be
contained
No additional risks
'l°hc plume would be
contained. No impart
Would be achieved.
Clean-up standards likely
would be achieved in
approximately 10 to 12
years
Complies with surface
water discharge permit
requirements
Not applicable
No additional risks.
The plume would be
contained
No additional risks
The plume would be
contained. No impact
in
• Approximate Time I.'mil
('.Iran-up Manifolds An- Mi'
Several dec:idrs
or limber
Several decades
or loii)>er
II) in Uye:irs
It I lit 12 years
10 in U years
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TABLE 13. Comparison of Alternatives.
2986 and 3000 Qakmegd Vi)laRe Court.
Santa Clara, California
(continued)
Adequacy of Control*
Ahemative I
No Action
3. Long Term Effcctheneaa and
Permanence
- Magnitude of Residual RUk
Will not change current
level of risk, but level of
risk will decrease with
lime. Affected ground
water will be above
clean-up standards for
several decades or
longer.
No controls Involml
•Permanence of Remedial
Action
• Effectiveness In Achieving
Remedial Action Objectives
4. Reduction ofToxIciry,
Mobility and Volume through
Treatment
•Amount of Hazardous
Material Treated
Permanent
Remedial objectives will
be met In several decades.
or longer by natural
attenuation proccssr*
None
Alternative II
Institutional Controls
and Ground Water
Will not change current
level of risk, but level of
risk will decrease with
lime. Affected ground
water will be above
clean-up standards for
several decades or.
longer.
Adequate to prevent
potential exposure to
humans
Permanent
Remedial objectives will
be met in several decades
or longer by natural
attenuation promises
None
Alternative III
Ground Water
Extraction and
CAC Treatment
Ground water will
eventually be restored
to safe drinking water
standards,
Adequate to prevent
potential exposure- to
humans
Permanent
Rcmcdia[ob)ccllves will
he met
Approximately 2.050,000
gallons affected ground
water treated per year.
Greater than 99 percent
V(X'. removal prior to
discharge
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
Ground water will
eventually be restored
to safe drinking water
standards.-
Adequate to prevent
potential exposure to
humans
Permanent
Remedial objective* will
.be met
Approximately 2.0)0.000
gallons affected ground
water treated per year.
Greater than 99 percent
VOT. removal prior to
discharge
Alternative V
Ground Water
Extraction and
Biological Treatment
Ground water will
eventually be restored
to safe drinking water
standards,
Adequate to prevent
potential exposure to
humans
Permanent
Remedial objectives will
be met
Approximately 2.0)0.000
gallons affected ground
water treated per year.
Greater than 99 percent
VOC removal prior to
discharge
-------
TABLE 13. Comparison of Alteratives.
and 3000 Oakmead Village CourL
§ania Clara. California
(continued)
Alternative I
No Action
Alternative II
Institutional Controls
and Ground Walcr
4. Reduction oTToxklty.
Mobility »nd Vofeme throuth
Treatment
(continued)
- Reduction of Toxkhy, None
Mobility and Volume
. • Irreversible Treatment None
• Type and Quantity < f None
Treatment Residual
}. OvcraJI Protection of Human
Health and the Environment
• Human Health
None
None
N«CH'
Alternative III
Ground Water
Extraction and
GAG Treatment
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
Alternative V
Ground Water
Extraction and
Biological Treatment
All significantly reduced All •Ignlficanily reduced All significantly reduced
Ye*
Approximately 2.000 oo
4,000 pound* of upcnJ
carbon per year requiring
di*pn.Hal/rci;enerai Ion
Ye*
NO!*'
None
in
in
> Environment
Negligible Impact since
discharge of impacted
ground water to the SI'
Ray and vicinity creeks
unlikely
Negligible impact since
diM-harfgo of impacted
ground water to the SI'
Hay and vicinity crocks
unlikely
Plume contained
l)iscbar)p of treated
ground water to Calaltaxas
Creek under NI'DKS permit
Hume contained.
DisctiarKC of Healed
ground water to Calabaus
-------
TABLE 13. Comparison of Alternatives.
JZ986 and 3000 Qakmcad Village Court.
Santa Clara, California
(continued)
6. Impkmntablllty
- Technical Feasibility
• Administrative feasibility
• Availability of Materials and
Scrvhvj.
Alternative I
No Action
Alternative II
Institutional Controls
and Ground Water
Alternative III
Ground Water
Extraction and
GAG Treatment
No construction required No construction required System constructed and
Operational
Very little administrative Kasily Implemented.
work required Hnforccmcnt of deed
restrictions could be
difficult
None required
None required
7. Costs
-Capitol
• Annual O & M
Present Worth Analysis
- 10 years of operation
.•12 years of operation
SO
SO
SO
SO
$5 .000 to $8.000
$5.000 to SH.OOO
$15.500 to S73.U10
$5l.500lo$H2.700
Required permits already
obtained.
Alternative IV Alternative V
Ground Water Extraction
and Oxidation/ Extraction and
Reduction Treatment Biological Treatment
Oxidation/Reduction Bloreactor would likely
unit would likely have to have to be custom
be custom manufactured manufactured. Pilot study
would have to be conducted
Required permits already Required permits already
obtained obtained
Services, components and Experience technicians to Experienced technicians to
materials easily obtained. maintain unit may not be perform dally maintenance
Carbon can be replaced readily available operations may not bo
with one to two days notice readily vallablc
$119.000
S63.OOnioSl2l.000
S6ZMKXMoSl.l02.OnO
$705.300 to $1.217.000
S 168,000
SI71.000 to $407,000
S 188.000
$101.000 to $137,000
SI.5VMOOIO S3.613.HOO $1.006.90010 Sl.WH.flW
$1.759.40010 $-(,123.200 St.127.900 to Sl.-t63.000
-------
TABLE 13. Comparison of Alternatives.
?986 and 3QOO Qakmead Village
Santa Clara. California
Ccontinucd)
8. Stole Acceptance
Alternative I
No Action
Acceptance unlikely
to be granted.
Alternative II
Institutional Controls
and Ground, Water
Acceptance unlikely
to be granted.
Alternative III
Ground Water
Extraction and
GAG Treatment
Ground water extraction
and treatment are
. approved technologies
bytheCRWQCBandfiPA.
NPDES permit has been
issued for the site.
Alternative IV
Ground Water Extraction
and Oxidation/
Reduction Treatment
Ground water extraction
and treatment are
approved technologies
by the CRWQCB and EPA.
NPDES permit has been
Issued for the skc.
Alternative V
Ground Water
Extraction and
Biological Treatment
Ground water extraction
and treatment are
approved technologies
by the OtWQCB and EPA.
NPDES permit has been
Issued for the site.
9. Community Acceptance
Public reaction likely
to be negative.
Public reaction likely
to be negative.
Publk reaction likely
to be positive since
ground water extraction
and treatment has been
implemented at the site
since 198V
Public reaction likely
to be positive since
ground water extraction
and treatment has bcvn
Implemented at the site
since 1985.
Public reaction likely
to be positive since
ground water extraction
and treatment has brtii
Implemented at ilic Mir
since 198V
-------
10.0 STATUTORY DETERMINATIONS
The selected remedies are protective of human health and the
environment, 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 th
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