United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R09-91/061
June 1991
&EPA Superfund
Record of Decision:
South Bay Asbestos Area
(Amendment), CA
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50272-101
REPORT DOCUMENTATION i. RETORT NO. 2.
PAGE EPA/ROD/R09-91/061
4.^fltend Subtitle
^ERFUND RECORD OF DECISION
^Buth Bay Asbestos Area, CA
First Remedial Action (Amendment)
7. Author(s)
9. Performing OrgalrUation Name and Address
12. Sponsoring Organization Name and AddreM
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. Recipient's Accession No.
S. Report Date
06/26/91
a.
8. Performing Organization Rept No.
10. Pro)ect/Ta*k/WorkUnitNo.
11. Contnct(C) or Grant(G) No.
(C)
(G)
13. Type of Report A Period Covered
800/000
14.
15. SuDotemerrtarv Note*
16. Abstract (Limit: 200 words)
The 550-acre South Bay Asbestos Area site consists of a ring levee in Alviso, San Jose,
California. Land use in the area is mixed residential, commercial, light industrial,
and agricultural. A 300-acre wetlands area is located adjacent to the site and is
partially covered by the levee. The ring levee was constructed by the City of San Jose
as_an emergency measure during a flood in March 1983, but a number of subsequent EPA
gations determined that the levee soil was comprised of 40 percent asbestos. In
and 1987, EPA conducted several emergency response actions to reduce asbestos
exposure around the site including the removal of an asbestos pile, paving and covering
local roads and lots, and spraying the levee with a dust-suppressing polymer. A 1988
Record of Decision (ROD) provided for installation of a vegetated soil cover over the
levee. A subsequent 1989 ROD addressed the remediation of portions of the site not
previously addressed and provided for paving of contaminated truck yards, monthly wet
sweeping of streets, removal of asbestos waste debris, cover requirements, inspections,
deed restrictions on landfills, and site maintenance and monitoring. This ROD amends
the 1988 ROD for the asbestos-contaminated soil in the ring levee and surrounding area.
The primary contaminant of concern affecting the soil is asbestos, an inorganic.
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - South Bay Asbestos Area, CA
First Remedial Action (Amendment)
Contaminated Medium: soil
Key Contaminants: inorganics (asbestos)
b. IdenWera/Open-Ended Terms
c. COSATI Reid/Group
IB^^MabUty Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
32
22. Price
(See ANSI-Z39.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R09-91/061
Bay Asbestos Area, CA
Remedial Action (Amendment)
Abstract (Continued)
The selected remedial action for this site includes excavating and disposing offsite
25,000 cubic yards of asbestos-contaminated levee soil; restoring any wetlands areas
located under the levee, or which were disturbed by the excavation; and conducting soil
sampling. The estimated present worth cost for this remedial action is $2,100,000.
There are no O&M costs associated with this remedial action.
PERFORMANCE STANDARDS OR GOALS: The chemical-specific soil cleanup goal for asbestos is
based on health-based criteria, and is 1 area percent.
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RECORD OF DECISION AMENDMENT
RING LEVEE OPERABLE UNIT
SOUTH BAY ASBESTOS AREA
ALVISO DISTRICT, SAN JOSE, CALIFORNIA
June 1991
SFUNO RECORDS CTR
2165-00044
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TABLE OF CONTENTS
Page
DECLARATION 1
RECORD OF DECISION SUMMARY 4
I. Site Name, Location, and Description 4
II. Site History 6
III. Community Participation 9
IV. Risk Assessment 9
V. Applicable or Relevant and Appropriate Requirements 11
VI. Description and Comparison of Alternatives 16
VII. Summary of the Comparative Analysis of Alternatives 18
VIII. The New Selected Remedy 21
IX. Statutory Determinations 22
Attachments:
Appendix I
- Asbestos Analytical Techniques
- Problems with Using Asbestos Data in Quantifying Risk
- Cleanup Goals for the South Bay Asbestos Area Site
Responsiveness Summary
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RECORD OF DECISION AMENDMENT
DECLARATION
Site Name
Alviso Ring Levee
Operable Unit
South Bay Asbestos Area
Site Location
Community of Alviso
San Jose, California
Statement of Basis and Purpose
This document amends the selected remedial action for the
Ring Levee Operable Unit of the South Bay Asbestos Area, located
in the community of Alviso in the City of San Jose, California.
This document was developed in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
as amended by the Superfund Amendments and Reauthorization Act of
1986 (CERCLA), 42 U.S.C. Section 9601 et. seq., and the revised
National Contingency Plan, 55 Fed. Reg. 8666 et. seq. (March 8,
1990) to be codified at 40 C.F.R. Part 300. This decision is
based on the administrative record for this site. The attached
Administrative Record Index (Exhibit 1) identifies the documents
on which the selection of the remedial action is based.
Assessment of the Site
Actual or threatened releases of asbestos from the Ring
Levee, 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.
Description of the Selected Remedy
This Record of Decision amends the previous Record of Deci-
sion for the Alviso Ring Levee Operable Unit (# RO9-88/026) dated
September 29, 1988. The overall remedy for the rest of the South
Bay Asbestos Area site was selected in a separate Record of Deci-
sion (# RO9/89/044) dated September 29, 1989. The previous ROD
for the ring levee selected a soil cover remedy consisting of 12
inches of compacted soil base, and 6 inches of topsoil planted
with native vegetation to control erosion. The ROD further
provided for environmental mitigation required under Section 404
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of the Clean Water Act, 33 U.S.C. Section 1344, for impacts of
the soil cover, and for deed restrictions to prevent disturbance
of the soil cover.
EPA is now amending the Record of Decision to select the
removal alternative. This remedy, although favored by many mem-
bers of the community and the potentially responsible parties,
was not originally selected due to several implementation
problems. EPA was concerned about the loss of flood protection
once the levee was removed, the potential for increased asbestos
exposure during levee excavation, loading and transport, and also
the projected high cost for landfill disposal of the levee
material. Acceptable solutions to these problems have since been
proposed; complete removal of the levee is now EPA's preferred
alternative.
The new selected remedy includes:
- Removal of the entire levee, after flood control improve-
ments on the Coyote Creek are completed. (Completion is currently
expected in 1994.) Post-removal sampling shall be conducted to
confirm that the levee has been completely removed;
Continued polymer spraying of the levee for dust control,
semiannually or as needed, until the levee is removed;
- Use of stringent dust control measures during levee
removal;
Off-site disposal of levee material in compliance with
federal and state laws and regulations;
Restoration of the previously existing wetlands underly-
ing the levee.
The estimated costs associated with levee removal are ap-
proximately $ 2.1 million. Once the levee is removed, no long
term monitoring and maintenance will be required, as this source
of contamination will no longer be present in the Alviso com-
munity.
The State has no technical objections to the selected
remedy.
Statutory Determinations
The removal remedy for the Ring Levee Operable Unit of the
South Bay Asbestos Area meets the remedy selection standards in
CERCLA Section 121, 42 U.S.C. Section 9621, and the National Con-
tingency Plan, 40 CFR Part 300. The selected remedy is protec-
tive of human health and the environment. The selected remedy
attains the Federal and State requirements that are legally ap-
plicable or relevant and appropriate under the circumstances of
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the release or threatened release, and is cost effective. This
remedy utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable; however, becaxise
treatment of the principal threats of the site was not found to
be practicable, this remedy does not satisfy the statutory
preference for treatment as a principal element.
Since the revised selected remedy calls for the complete
removal of the Ring Levee, EPA currently anticipates that five-
year reviews will not be required specifically for the Ring Levee
Operable Unit, following completion of the remedial action.
However, in accordance with CERCLA Section 121(c), 42 U.S.C. Sec-
tion 9621(c), a review may be conducted if the remedial action
has not been completed within five years of its initiation. In
addition, because hazardous substances will remain elsewhere at
the South Bay Asbestos Area site, EPA will conduct five year
reviews for the overall site, as set forth in the Record of Deci-
sion dated September 29, 1989. Any reviews of the ring levee
remedial action required by CERCLA Section 121(c), the NCP and
any applicable EPA guidance may be conducted in conjunction with
the reviews for the overall site.
Daniel W. McGovern Date
Regional Administrator, EPA Region 9
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RECORD OF DECISION AMENDMENT
SUMMARY
I. Site Name, Location, and Description
The South Bay Asbestos site is located at the northern end
of the Santa Clara Valley and at the southernmost extent of San
Francisco Bay. The site, which encompasses the community of Al-
viso, is a mix of residential, commercial, light industrial and
agricultural land uses, comprising an area of about 550 acres
(Figure 1). Approximately 1700 residents live in Alviso. The
town is located in a quiet section of the Silicon Valley between
Highway 237 to the south, rapidly growing Santa Clara to the west
and south and expanding office development to the east and north-
east.
Alviso is highly susceptible to flooding, due to its low
elevation and proximity to the Bay. Flood-producing storms occur
within the region every few years. Two major streams, the
Guadalupe River and Coyote Creek enter the Bay to the west and
north-east of Alviso, respectively. These rivers do not provide
natural local drainage since they are leveed to prevent overbank
flooding. The Guadalupe River was channelized in 1963 by the
Santa Clara Valley Water District (SCVWD) to provide for greater
flood flow capacity. The streams are under tidal influence and
therefore, discharge to the Bay is impeded during high tides.
Numerous salt evaporation ponds are present between Alviso and
the Bay, further impeding natural drainage into the Bay.
The development of agriculture in the region was facilitated
by widespread ground water withdrawal from irrigations wells.
Between 1934 and 1967, aquifer compaction due to overpumping
caused the ground surface of the Santa Clara Valley to subside
four to six feet, to an elevation below sea level, significantly
increasing the potential for flooding. The land surrounding Al-
viso has been artificially raised with soil and debris fill, some
containing asbestos, to offset the effects of subsidence.
The community of Alviso is adjacent to Bay wetlands. Over
the last century, most of the tidal flats and marshlands which
surround San Francisco Bay have been filled or altered. Near Al-
viso, a fragment of wetlands survives as the New Chicago Marsh, a
National Wildlife Refuge covering approximately 300 acres. The
ring levee was partially constructed in wetlands; approximately
2.82 acres of wetlands were buried under the levee.
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The wetlands adjacent to Alviso are a significant wildlife
habitat because they provide an interface between fresh and
saltwater environments. The wetlands support several endangered
or threatened species, including the Salt Marsh Harvest Mouse
(Reithrodontorovs raviventrisl, California Clapper Rail (Rallus
lonqirostris obsoletus), Golden Eagle (Aguila chrvsaetos),
and Peregrine Falcon fFalco perearinus). Small mammals and a
great number of birds and waterfowl species use the wetlands and
surrounding upland habitats (i.e., land elevated above the water
level of the marsh).
Description of the Levee
The ring levee, which extends around the community of Alviso
on the east, north, and northwest (Figure 2) , was constructed of
approximately 25,000 cubic yards of material and is approximately
four to six feet in height, two miles in length, and has a
trapezoidal shape. The levee has side slopes generally steeper
than 2:1, and covers an area of approximately eight acres. A
narrow, approximately two-foot wide path exists along the crest.
The ring levee immediately adjoins School Street, the homes
on the eastern side of Alviso (the O'Neil Tract), and continues .
along Grand Blvd. and Spreckles Ave. The levee is isolated from
public streets along the northwest, where it continues behind the
commercial trucking operations along State Street. The steep
outboard or bayward side of the levee abuts wetlands areas along
Spreckles Avenue and along the commercial truckyard operations.
At its western end, the levee borders two private homes. One
home owner has fenced the levee to prevent foot traffic. The
levee terminates at the northwestern end of town.
The levee immediately adjacent to streets and homes is used
heavily as a pedestrian walkway. Residents, and particularly
children, have been seen walking and jogging along the berm,
playing on the slopes, picnicking or riding bicycles on or ad-
jacent to the levee. The levee in these areas is barren of
vegetation. In addition, it appears that motor vehicles may also
drive over the levee. Areas removed from public access tend to
be well-vegetated with grasses and weeds.
II. Site History
The City of San Jose constructed the ring levee as an emer-
gency measure during a flood in March 1983, which caused the
evacuation of the entire town for sixteen days as flood waters
overtopped the Coyote Creek channels and existing levees. The
ring levee was constructed in an attempt to divert existing and
possible future flood waters from the community. Because of the
urgency of the situation, San Jose did not obtain the necessary
permits from the Army Corps of Engineers (COE), who has jurisdic-
tion over such construction, and did not consult with other
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AGRICULTURAL LAND
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South Bay Asbestos Site
SITE LOCATION MAP
SHOWING RING LEVEE
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APPROXIMATE SCALE M FEET
Camp Oresier 4 McKee
NOTC: lASt MA^ ADAPTtO MOM
KfPORT. >E8RUA)IY. 1M»
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federal and state agencies. San Jose planned to obtain an "after
the fact permit" from the COE; however, no permit was ever issued
for the levee. The levee was constructed with serpentine soil
and rock from Azevedo Quarry, which was later found to contain up
to 40% asbestos.
The South Bay Asbestos Area site was proposed for inclusion
on the National Priorities List in June of 1984, and was listed
on the NPL in October 1984, with a score of 44.68. After assum-
ing the lead role from the state in 1986, EPA conducted several
emergency measures to reduce asbestos exposure around the town,
including paving a lot adjacent to the George Mayne School,
paving an unpaved section of Spreckles Avenue, and removing an
asbestos debris pile and chip sealing the road and parking lot at
the Environmental Education Center, located within the New
Chicago Marsh, to the east of Alviso. EPA also sprayed the ring
levee with a dust suppressing polymer in 1986 and again in 1987.
In April 1988, the City of San Jose signed a Consent Agreement
with EPA which required the City to maintain the levee by peri-
odically applying the sealant and to. conduct operation and main-
tenance activities at the Environmental Education Center. The
City sprayed the levee in July of 1988 and again in October of
1989,
In April 1988, EPA released the Operable Unit Feasibility
Study (OUFS) for the ring levee, and signed a Record of Decision
selecting a vegetated soil cover for the levee in September 1988.
Although the cover proposal received a generally favorable
review, the Potentially Responsible Parties (PRPs) and many of
the community members preferred the complete removal of the
asbestos-contaminated levee. The ROD noted that the PRPs had in-
dicated an interest in pursuing complete removal of the levee, an
option that EPA did not select due to its high cost, the propor-
tionally greater potential for asbestos releases during removal
operation, the institutional, regulatory, and technical problems
associated with replacing the levee's flood protection function,
and the difficulties associated with disposing of the removed.
material. The 1988 ROD noted that complete removal of the levee,
assuming it could be accomplished in a safe manner, would be at
least as protective as the selected soil cover remedy and would
be a permanent solution. The ROD further stated that if the PRPs
formally proposed to remove the levee, and could identify accept-
able solutions to the problems associated with this option, EPA
would consider amending the Record of Decision to select the
removal alternative.
EPA has identivied two potentially responsible parties, the
City of San Jose and A.J. Raisch Paving Company. San Jose con-
structed the levee and A.J Raisch Paving Company was the supplier
of the material. EPA sent general notice letters to San Jose in
July 1987, and to Raisch in February 1988. Special Notice let-
ters pursuant to CERCLA Section 122 were sent in August 1988.
8
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The Remedial Investigation/Feasibility Study for the South
Bay Asbestos Area Site was released for public comment in
February 1989, and in September 1989, EPA signed a second Record
of Decision for the overall South Bay Asbestos Area site, to ad-
dress those portions of the site that were not included in the
Ring Levee Operable Unit. The overall remedy includes: paving
contaminated truck and industrial yards with asphalt or other
suitable resurfacing material; control of street dust emissions
through monthly wet sweeping; removal of asbestos waste debris;
cover requirements, inspections, and deed restrictions on
landfills; and routine maintenance and monitoring.
A more complete history of EPA and interagency site inves-
tigations and response actions may be found in the previous RODs
for this site.
III. Community Participation
All requirements for public participation as specified in
Section 113(k)(2)(B)(i-v) and Section 117 of CERCLA and the NCP
have been satisfied. The new proposed plan was mailed to resi-
dents and interested members of the public, and copies were made
available in the information repository at the San Jose Public
Library (Alviso Branch) and in the administrative record file on
review at the EPA Region 9 Docket Room. A public comment period
on the new proposed plan was held February 26 - March 27, 1990.
Notice of the new proposed plan and public comment period were
published in both English and Spanish on February 20, 1990 in the
San Jose Mercury News and Milpitas Post. No comments on the new
proposed plan were submitted during the public comment period.
However, responses to comments concerning the levee that were
made during the February 15, 1989 public meeting on the Proposed
Plan for the remediation of the overall South Bay Asbestos Area
Site are provided in the Responsiveness Summary, Attachment A of
this ROD.
IV. Risk Assessment
Asbestos is the contaminant of concern at this site. The
ring levee has been identified as one of the primary sources of
asbestos within the community. Concentrations of asbestos in the
levee range from non-detect to 40% by area using polarized light
microscopy.
Asbestos is a generic term referring to two groups of
naturally-occurring hydrated silicate materials having a fibrous
crystalline structure. Chrysotile fibers belong to the serpen-
tine group; actinolite, amosite, anthophyllite, cummingtonite,
crocidolite, and tremolite belong to the amphibole group. Asbes-
tos fibers have been widely used because of their high tensile
strength an flexibility and their noncombustible, nonconducting
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and chemical-resistant properties. The fibers have been used in
insulation, brake linings, cement pipe, paper products, textiles
and building products.
Asbestos is a known human carcinogen and has been the sub-
ject of numerous epidemiological studies. There is no threshold
level of exposure below which there is no risk. The primary dis-
eases that have been associated with asbestos exposure are asbes-
tosis, lung cancer, and mesothelioma; others include cancers of
the larynx, pharynx, gastrointestinal tract, kidney, and ovary as
well as respiratory diseases such as pneumonia.
Lung cancer is currently responsible for the largest number
of deaths from exposure to asbestos. It has been associated with
exposure to all principal commercial asbestos fiber types. Ex-
cessive lung cancer rates have been documented in groups of
workers involved with the mining and milling of asbestos and the
manufacture and use of asbestos products. Studies in which the
extent of exposure can be approximated provide evidence that lung
cancer increases linearly with both level and duration of ex-
posure .
Human studies have also shown that exposure to asbestos can
cause mesothelioma, a cancer that occurs as thick diffuse masses
in the serous membranes (mesothelia) that line body cavities.
Mesothelioma occurs in the pleura (the membrane that surrounds
the lungs and lines the lung cavity) and the peritoneum ( which
surrounds the abdominal cavity). Epidemiological studies suggest
that the incidence of mesothelioma is related to dose and time
from first exposure.
Asbestosis, which involves fibrosis of lung and pleural
tissues, is another serious chronic disease associated with high
levels of exposure to asbestos. A full discussion of the health
effects of asbestos is found in the EPA document Airborne Asbes-
tos Health Assessment Update. EPA 600/8-84-003F. June 1986.
To evaluate the risks posed by the ring levee under worst
case scenarios, two separate experiments were conducted by
California DHS in 1985 on the levee itself. The experiments were
designed to simulate actual exposures based on observations of
adults and children walking, bicycling, crawling, and playing on
the levee. The first experiment consisted of raking and shovel-
ing loose levee soil directly upwind of a sampler. An electric
fan was positioned to simulate wind and blow the disturbed soil
into the sampler. The second experiment consisted of shoveling
the soil on the levee and collecting air samples in an adult's
breathing zone; a toy truck was then used to simulated play,
while air samples were collected downwind in a child's breathing
zone, without a fan.
The results from the first experiment exceeded the Occupa-
tional Safety and Health Act (OSHA) Permissible Exposure Limit
(PEL) of 0.2 fibers ber cubic centimeter by two orders of mag-
10
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nitude. The results from the second experiment exceeded the OSHA
PEL by one order of magnitude. Although the simulations repre-
sented an extreme asbestos exposure scenario, the exceedences of
OSHA standards in a residential setting indicated that uncontrol-
led levee dust posed a significant health threat to the com-
munity. Since this time, a dust suppressant polymer has been pe-
riodically applied to the levee to control the release of dust,
until a more permanent remedy is implemented.
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 notation
(e.g. 1 x 10 6). An excess lifetime cancer risk of 1 x 10 6 in-
dicates that, as a plausible upper bound, an individual 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. When preliminary
risk calculations were made using the air concentrations from the
DHS experiments and worst case exposure scenarios, the risks
greatly exceeded the EPA's acceptable risk range of 10~4 to 10 .
V. Applicable or Relevant and Appropriate Requirements
Under Section 121(d) of the Comprehensive Environmental
Response Compensation and Liability Act (CERCLA), 42 U.S.C. Sec-
tion 121 (d), remedial actions must attain a degree of clean-up
which assures protection of human health and the environment.
Additionally, remedial actions that leave any hazardous sub-
stance, pollutant, or contaminant on-site must meet a level or
standard of control that at least attains federal and more strin-
gent state standards, requirements, criteria, or limitations that
are "applicable or relevant and appropriate" under the cir-
cumstances of the release. These requirements, known as "ARARs",
may be waived in certain instances. Additionally, only substan-
tive (in contrast to administrative) federal and state require-
ments need to be followed.
"Applicable" or "relevant and appropriate" requirements are
further defined in the revised National Contingency Plan (NCP),
55 Fed. Reg. 8666 (March 8, 1990), 40 C.F.R. part 300.
"Applicable" requirements are those clean-up standards, standards
of control and other substantive requirements, criteria or
limitations promulgated under federal environmental or state en-
vironmental or facility siting law that specifically address a
hazardous substance, pollutant or contaminant, remedial action,
location or other circumstance at a CERCLA site. "Relevant and
appropriate" requirements are those clean-up standards, standards
of control, and other substantive requirements, criteria, or
limitations promulgated under federal environmental or state en-
vironmental or facility siting law that, while not directly
"applicable" to a hazardous substance, pollutant, contaminant,
remedial action, location, or other circumstance at a CERCLA
site, address problems or situations sufficiently similar to
11
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those encountered at the CERCLA site such 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.
Only those state standards that are identified by a state in a
timely manner and that are more stringent than federal require-
ments may be ARARs.
The determination of which requirements are "relevant and
appropriate" is somewhat flexible. EPA and the State may con-
sider the type of remedial actions contemplated, the hazardous
substances present, the waste characteristics, the physical
characteristics of the site, and other appropriate factors in
identifying ARARs. It is possible for only part of a requirement
to be considered relevant and appropriate.
There are three types of ARARs. The first type includes
"chemical-specific" (i.e. contaminant specific) requirements.
These ARARs are usually health- or risk-based numerical values or
methodologies that set limits on concentrations of specific haz-
ardous substances, pollutants, and contaminants in the environ-
ment. A second type of ARAR includes location-specific require-
ments which set restrictions on certain types of activities based
on site characteristics, for example, restrictions on activities
in wetlands, floodplains, and historic sites. The third type of
ARAR includes action-specific requirements. These are technol-
ogy- or activity-based restrictions which are triggered by the
type of action under consideration. As described in the NCP,
ARARs must be met during the implementation of the remedial ac-
tion as well as at its completion.
ARARs must be identified on a site-specific basis from in-
formation about specific chemicals at the site, specific features
on the site, and actions that are being considered as remedies.
Most of the ARARs listed below were identified as ARARs for
the soil cover remedy in the previous Record of Decision for the
Ring Levee Operable Unit. Differences for the new remedy-are
noted. Also, some additional ARARs described in the 1989 overall
ROD are also included, along with some additional explanation and
citations.
In addition to ARARs, EPA or the State may, as appropriate,
identify other advisories, criteria or guidance, not necessarily
promulgated requirements, to be considered for a particular
release. The "to be considered" (TBC) category consists of ad-
visories, criteria, or guidance that were developed by EPA, or
other federal or state agencies that may be useful in developing
CERCLA remedies.
Contaminant-Specific ARARs
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The following ARARs, while specific to asbestos, address
techniques relating to the implementation of the selected
remedial action, rather than health- or risk-based numerical
standards or methods. Thus, they might also be considered
"action-specific" ARARs.
1. Clean Air Act, National Emission Standards for Hazardous
Pollutants (NESHAPs) regulations (40 C.F.R. Sections 61.151,
61.152, 61.153)
NESHAPS, and similar BAAQMD regulations, require "no visible
emissions", specified cover requirements, dust suppression, wet-
ting methods or alternative approved control and dust suppression
methods for disposal and handling of asbestos-containing waste
material. The NESHAPs requirements for emissions control and
dust suppression is an ARAR for implementation of this remedy.
However, the specified cover requirements, while relevant and ap-
propriate for the original soil cover remedy, are not ARARs for
the removal remedy, since the levee will be removed rather than
covered.
In the previous ROD selecting the soil cover, the California
Bay Area Air Quality Management District (BAAQMD) regulations
(Reg. 11, rule 2, 305.3.1) were listed as an ARAR. However, as a
point of clarification, the BAAQMD wetting and dust suppression
requirements do not come under the NCP's definition of more
stringent state ARARs, because they are virtually identical to
the NESHAPs requirements.
2. Toxic Substances Control Act (TSCA) and Asbestos Hazard E'mef-
gency Response Act (AHERA) regulations, 40 C.F.R. 763.
EPA has promulgated regulations under TSCA and AHERA
(Subchapter II of TSCA) related to the inspection and management
of asbestos-containing material in schools. These regulations
utilize polarized light microscopy (PLM) as a measurement tech-
nique for detecting asbestos; the use of this measurement tech-
nique for asbestos is relevant and appropriate to the removal of
the Alviso ring levee. (See Appendix I for an explanation of the
use of PLM in determining the cleanup standard for asbestos at
the South Bay Asbestos Area site.)
Location-Specific ARARs
3. The Endangered Species Act of 1973 and regulations (16 U.S.C.
Section 1531 et seq.; 40 C.F.R. Section 6.302(h); 50 C.F.R. Parts
17 and 402.
Section 7 of the Endangered Species Act, 16 U.S.C. Section
1536, requires Federal agencies to ensure that their actions are
not likely to jeopardize the continued existence of any endan-
gered species or cause adverse modifications of critical habitat.
Endangered species (including Salt Marsh Harvest Mouse and
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California Clapper Rail) have been identified in the New Chicago
Marsh which abuts the site. Section 7 and related regulatory
requirements are therefore ARARs. 40 C.F.R. Section 6.302 (h)
describes the applicability of the Endangered Species Act to EPA
actions.
4. Clean Water Act, Section 404 (33 U.S.C. Section 1344) and
regulations, 40 C.F.R. 230 et.seg.; Executive Orders 11988
(Floodplain Management) and 11990 (Protection of Wetlands), May
24, 1977; 40 C.F.R. 6.302 (a) and (b) and 40 C.F.R. Part 6, Ap-
pendix A.
These requirements address wetlands protection and
floodplain management. The site is located in a floodplain and
in and adjacent to wetlands. Federal agencies are required to
avoid, to the extent possible, adverse impacts from destruction
of wetlands, and avoid support of new constructions in wetlands
if a practicable alternative exists. Section 404 and regulations
mandate that dredged or fill material should not be discharged
into aquatic ecosystems (in this case wetlands) unnecessarily,
and also set forth mitigation requirements.
5. National Historic Preservation Act, 16 U.S.C. Section 470f;
Historic Sites Act, 16 U.S.C. Section 461 et seq.; Archaeological
and Historic Preservation Act, 16 U.S.C. Sections 469 et. seq.;
Executive Order (E.O.) 11593 (Protection and Enhancement of the
Cultural Environment, May 13, 1971); 40 C.F.R. Section 6.301; and
36 C.F.R. Part 800.
Federal agencies are required to consider the effects of
their actions upon designated or potential historic, architec-
tural, archaeological, and cultural sites and natural landmarks.
The western portion of the levee borders on the older section of
Alviso, which is listed in the National Register of Historic
Places. To the extent that levee removal may impact this section
of town, the substantive requirements of these statutes, orders
and regulations are ARARs.
6. McAteer-Petris Act and regulations (California Government
Code, Title 7.2, Section 66600 et. seq.; California Administra-
tive Code (CAC) Title 14, Div. 5, Sec. 10110 et. seq.); Coastal
Zone Management Act, 16 U.S.C. Sec. 1451 et. seq.
The McAteer-Petris Act established the San Francisco Bay
Conservation and Development Commission (BCDC), which regulates
activities adjacent to the Bay through the San Francisco Bay Plan
document and permit requirements. Although remedial activities
conducted on-site are exempted from permits (CERCLA Section 121
(e)(l), 42 U.S.C. Section 9621(e)(l)), the substantive require-
ments of the Bay Plan are ARARs, to the extent that a BCDC permit
would otherwise be required.
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The Bay Plan also serves as the coastal zone management plan
for the San Francisco Bay, pursuant to the Coastal Zone Manage-
ment Act (CZMA), 16 U.S.C. Sec. 1451 et. seq.. Section 307(c)(l)
of the Coastal Zone Management Act (CZMA) requires that Federal
agencies conducting or supporting activities directly affecting
the coastal zone conduct or support those activities in a manner
that is consistent with approved State coastal zone management
programs.
Action Specific ARARs
7. Occupational Safety and Health Act (OSHA) regulations, 29
C.F.R. 1910.1000 and 1910.1001; 29 C.F.R. 1926.58.
OSHA has set a Permissible Exposure Limit (PEL) for asbestos
fibers at .2 fibers per cubic centimeter of air (f/cc) for oc-
cupationally exposed workers, as a eight-hour time-weighted
average, and an Excursion Limit of 1.0 f/cc averaged over a
thirty (30) minute period. OSHA regulations also specify protec-
tive measures to ensure that worker exposures do not exceed these
limits. These requirements are ARARs for the implementation o'f
the remedy as levee removal has the potential to generate sig-
nificant amounts of dust during excavation and loading ac-
tivities.
To Be Considered (TBCs):
1. U. S. Fish and Wildlife Service Mitigation Policy, 46 Fed.
Reg. 7644-7663 (Jan. 23, 1981).
This policy, identified as an ARAR in the previous ROD, is
more accurately a TBC. It defines four resource categories of
impacted habitats, and establishes mitigation goals and
guidelines for each category. According to USFWS, the mitigation
goal for any losses of habitat values for the wetlands near Al-
viso is no net loss of in-kind habitat values. Portions of the
levee were constructed in wetlands; removal of the levee will al-
low for restoration of the wetlands underlying the levee.
2. Memorandum of Agreement Between the Environmental Protection
Agency and the Department of the Army Concerning the Determina-
tion of Mitigation Under the Clean Water Act (CWA) Section
404(b)(l) Guidelines, February 6, 1990.
This Memorandum of Agreement sets forth the policy and pro-
cedures to be used in the determination of the type and level of
mitigation necessary to demonstrate compliance with the Clean
Water Act (CWA) Section 404(b)(l) Guidelines, 40 C.F.R. Section
230 et. seq. (listed above as a location-specific ARAR).
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VI. Description and Comparison of Alternatives
As described in section II above, the original 1988 Record
of Decision selecting the soil cover alternative, stated that EPA
did not select the alternative of complete removal of the levee
iue to its high cost, the proportionally greater potential for
asbestos releases during removal operation, the problems as-
sociated with replacing the levee's flood protection function,
and the difficulties associated with disposing of the removed
material. This section sets forth a comparison of the two alter-
natives, and also describes how the problems associated with the
removal alternative have been and will be addressed. A descrip-
tion of the other proposed remedies evaluated in the Operable
Unit Feasibility Study (OUFS) may be found in the September 1988
Record of Decision.
1. Soil Cover.
The Soil Cover Alternative involved stripping and rough
grading the existing levee, placing a minimum of 12 inches of
compacted soil over the levee, placing 6 inches of top soil over
the compacted soil, and revegetating the levee and side slopes.
Native vegetation would be selected for the levee which would
provide erosion protection and provide cover for the Salt Marsh
Harvest Mouse. A temporary irrigation system would be installed
until vegetation was re-established. Previously existing wet-
lands would remain buried under the levee, because the levee
would be left permanently in place. In addition, the cover would
further expand the encroachment of the levee into the New Chicago
Marsh. Therefore, section 404 of the Clean Water Act would re-
quire creation, enhancement or restoration of wetland areas else-
where to compensate for, at a minimum, the additional loss of
wetlands due to installation of the cover. The soil cover alter-
native would also include deed restrictions on the levee to
prevent future disturbance of the cover.
2. Levee Removal
The levee removal alternative consists of excavating the
levee material down to pre-existing grade and transporting the
material to an approved off-site disposal site. Following the
removal, the underlying exposed soil will be sampled to verify
that the removal is complete. (See Section VIII for a descrip-
tion of the cleanup criteria.) Once the levee removal has been
completed, wetland and adjacent upland areas, including areas
that were buried under the ring levee and its appurtenant struc-
tures and areas disturbed by remedial action activities will be
restored. Restoration shall include any necessary excavation and
grading, and replanting the areas with native vegetation.
The levee removal alternative was referred to in the OUFS
and the September 1988 ROD as the "off-site RCRA landfill
alternative". As stated in the OUFS, this was the only alterna-
tive evaluated that would have eliminated all risks at the site
16
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due to asbestos in the ring levee. As originally proposed, this
alternative provided for excavation and off-site disposal of the
levee material at a landfill meeting the requirements of the
Resource Conservation and Recovery Act (RCRA), 42 U.S.C. Sec.
6901 et. seq. However, following the initial screening of
remedial action alternatives in the OUFS, EPA screened out and
eliminated levee removal from further consideration on the basis
of cost and other factors; the estimated capital costs to remove
and dispose of the levee material in an off-site RCRA landfill
were three to seven times higher than the containment and cover
alternatives.
EPA has subsequently determined that, since asbestos is not
classified as a hazardous waste under the federal Resource Co'n-
servation and Recovery Act, disposal in a RCRA (Class I) landfill
will not be required. This makes levee removal a more cost-
effective alternative than originally calculated. Under Califor-
nia law, however, asbestos is classified as a non-RCRA hazardous
waste. Therefore, the levee material must either be disposed of
in an appropriate landfill qualified to accept such material, or
safely re-used in a manner that permanently encapsulates the
material and that is protective of public health and the environ-
ment. Such disposal or reuse must comply with all applicable
federal and state laws and regulations and must be approved by
EPA.
One option being considered is to use the levee material as
a paving sub-base for an off-site roadway. Once buried under
permanent pavement, asbestos emissions would be effectively con-
trolled. If the material is removed, transported and reused
safely, and if all federal and state requirements are met, this
option would be protective. Landfill disposal costs would not be
incurred under this option.
The original purpose of the Alviso ring levee was to provide
temporary flood protection for the Alviso community. The loss of
flood protection following levee removal was one consideration
which led to EPA's initial rejection of the removal alternative.
The U.S. Army Corps of Engineers, in conjunction with the Santa
Clara Valley Water District, is currently constructing a fresh-
water flood control project on the Coyote Creek and Guadalupe
River. Once the flood control project is completed, the ring
levee will no longer be needed for flood protection and can be
safely removed. The ring levee will not be removed until after
completion of the flood control project, which is currently ex-
pected to occur in 1994.
As the excavation of material may generate a significant
amount of dust, dust suppression techniques will be required.
Examples of dust suppression techniques which could be used in-
clude, but are not limited to, wetting the material with water,
using a chemical dust suppressent, or installing a tent over por-
tions of the levee as it is removed. The specific dust suppres-
sion measures to be used will be included in the Remedial
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Design/Remedial Action (RD/RA) workplan, which must be approved
by EPA. As levee removal will not take place until permanent
flood control improvements are in place, in the interim, the
levee will be resprayed with a dust suppressing polymer, semian-
nual ly or as needed.
VII. Summary of the Comparative Analysis of Alternatives
This section presents a comparison of alternatives using
nine component criteria. These criteria, listed below, are set
forth in the National Contingency Plan and are derived from re-
quirements in CERCLA Section 121(a) and (b).
1. Overall protection of human health and the environment.
2. Compliance with ARARs
3. Long-term effectiveness and permanence.
4. Reduction of toxicity, mobility, or volume through treatment.
5. Short-term effectiveness.
6. Implementability.
7. Cost.
8. State Acceptance.
9. Community Acceptance.
1. Overall Protection of Human Health and the Environment
The soil cover alternative was designed to control the
release of asbestos fibers by providing a physical barrier be-
tween the contaminant and the potential receptors. The cover
would be planted with native vegetation to control erosion, and
with maintenance, would provide a high degree of long-term public
health protection.
Removal of the levee will provide even more effective long
term protection, as the source of contamination will no longer
remain in the community. The removal alternative was the only
alternative evaluated in the OUFS that would eliminate all risks
at the site due to asbestos in the Ring Levee. Removal of the
levee would provide the maximum possible protection for the com-
munity since asbestos in the levee will be removed from Alviso.
However, effective dust control measures will be necessary to en-
sure adequate protection of human health and the environment as
the levee is being removed. Also, periodic application of a dust
suppressant to the levee will be necessary to ensure protection
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of public health and the environment until the levee can be
removed, following completion of the Coyote Creek flood control
project.
2. Compliance with ARARs
The ARARs pertinent to the removal remedy are described in
Section V above. With the use of stringent dust control measures
during implementation, the levee removal remedy will comply with
all ARARs. The soil cover remedy would also have complied with
all ARARs identified for that remedy in the 1988 ROD.
A notable difference between the soil cover and removal
remedies pertains to wetlands mitigation ARARs. Constructing a
soil cover over the levee would have resulted in additional loss
of wetlands. Consequently, wetlands mitigation would have been
required in order for the soil cover alternative to comply with
ARARs. However, removal of the levee can be accomplished with no
additional filling of wetlands, and will also allow the wetland
areas originally lost under the levee to be restored.
3. Long-Term Effectiveness and Permanence
With adequate long-term maintenance, the cover alternative
would effectively control asbestos releases from the levee. Con-
ceivably, the soil cover could require major repairs in the event
of flooding or seismic activity. Lack of maintenance and cor-
responding erosion could also negatively affect the long-term ef-
fectiveness and permanence of the soil cover remedy. Because the
soil cover would result in asbestos remaining at the site, a five
year review would be required.
Removing the levee would provide a more permanent, highly
effective remedy, which would permanently eliminate asbestos
emissions in Alviso without the need for long-term maintenance or
repairs. Removal of the levee material would eliminate long-term
risks at the site due to the Ring Levee. After removal of the
levee, future use of the area would be unrestricted. Because the
asbestos-contaminated levee will be completely removed, EPA cur-
rently anticipates that five-year reviews will not be required
specifically for the Ring Levee Operable Unit. However, institu-
tional controls may be necessary to ensure the continued per-
manent encapsulation of the material at its off-site location.
4. Reduction of Toxicity, Volume or Mobility Through Treatment.
Because there is presently no feasible and reliable treat-
ment technology for asbestos to reduce its toxicity, mobility or
volume, no remedial alternative for this site utilizes treatment.
Therefore, both the soil cover alternative and the selected al-
ternative are consistent with the statutory preference for
selecting remedies that utilize a treatment technology which per-
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manently and significantly reduces the toxicity, mobility, or
volume of the hazardous substances, to the extent that such tech-
nologies exist.
5. Short-Term Effectiveness
Installation of the soil cover would provide short-term
public health protection. However, to control dust generated by
construction activities, dust control measures would need to be
implemented during the construction operation. It is estimated
that it would take four to five months to complete the soil cover
remedy following the initiation of remedial activities.
The removal alternative could potentially create significant
amounts of dust during excavation, loading and transport of
material which could be greater than the amount of dust generated
under the soil cover alternative. Therefore, it will be neces-
sary to employ strict dust control measures during the short
period of time that the removal is taking place, in order to en-
sure adequate short-term public health protection. In the short
term, until the levee is removed following completion of the al-
ternative flood control project, periodic polymer spraying of the
levee would protect against asbestos emissions. Removal of the
levee could be completed within 2 to 3 weeks of mobilization.
6. Implementability
Both the soil cover and removal alternatives are ap-
proximately equally implementable; both remedies may be ac-
complished easily using conventional equipment. Approximately 29
different private, public and commercial landowners own property
along the levee; easements or access rights must be obtained
prior to implementation of either remedy. However, one dif-
ference is that, since no long-term maintenance will be required
after the levee has been removed, long-term or permanent ease-
ments would not be necessary under the levee removal alternative.
7. Cost.
The cost of the soil cover alternative, including main-
tenance costs, was estimated to be $2.4 million. The estimated
costs for levee removal, adjusted for inflation over five years,
and assuming the material will be re-used offsite at minimal
cost, is $2.1 million. Since no long-term maintenance will be
required, there would be no maintenance costs associated with
levee removal. If the levee material can be used as a paving
sub-base for a roadway, minimal transportation and disposal costs
are anticipated. Disposal in a landfill would increase the cost
of this alternative, but would likely be significantly less than
the original estimated cost for disposal in a RCRA landfill.
8. State Acceptance.
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The California Department of Health Services (DHS) has no
technical objection to either the soil cover or removal alterna-
tives. As asbestos is a California-regulated hazardous waste,
DHS has expressed concern over the selection of a non-landfill
disposal or re-use site. EPA will consult with DHS prior to ap-
proval of any disposal site to ensure that such disposal or reuse
complies with state laws and regulations.
9. Community Acceptance
During the public comment period held on the original
proposed plan for the Ring Levee Operable Unit, held April 12 -
May 11, 1988, the removal alternative was supported by the com-
munity, provided that the levee would be replaced by alternative
flood protection. The Coyote Creek flood control improvements
currently under construction will provide permanent flood protec-
tion for Alviso. No public comments were received during the
February 26 - March 27, 1990 comment period. The few levee-
related comments that were received during the February 15, 1989
public meeting on the Proposed Plan for the overall South Bay As-
bestos Area are addressed in the Responsiveness Summary, Attach-
ment A of this ROD.
VIII. The New Selected Remedy
As discussed above, the new selected remedy for the Ring
Levee Operable Unit includes removal of the entire levee down to
pre-existing grade, as soon as practicable after completion of
the Coyote Creek flood control project. Prior to removal, the
levee will continue to be sprayed with a dust suppressing
polymer, semiannually or as needed. Effective dust control
measures will be used during the removal of the levee; the levee
material will be re-used or disposed off-site in a safe manner,
as approved by EPA, and will be consistent with federal, state
and local laws and regulations. Once the levee removal has been
completed, wetland and adjacent upland areas, including areas
that were buried under the ring levee and its appurtenant struc-
tures and areas disturbed by remedial action activities will be
restored.
As described in Appendix I, the cleanup goal of one area
percent as analyzed by polarized light microscopy will be used to
evaluate the thoroughness of the cleanup. Problems with asbestos
analytical techniques make establishing health-based clean up
goals difficult. The PLM method is used to measure asbestos
levels in bulk insulation samples pursuant to EPA regulations
promulgated under the Toxic Substances Control Act (TSCA) and As-
bestos Hazard Emergency Response Act (AHERA). EPA has selected
the one area percent clean up level for the South Bay Asbestos
Area site because one area percent is the generally accepted
detection limit for asbestos in soil using PLM. One area percent
by PLM has also been used in the past as an action level in emer-
gency response situations, and as a cleanup goal for remedial ac-
21
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tions at other Superfund sites. Following the removal of the
levee to pre-existing grade, the underlying soil will be sampled
to ensure that the removal is complete.
Once the levee has been removed, the public will no longer
be exposed to the asbestos hazards associated with the levee, and
the health and environmental risks associated with the levee will
be eliminated.
The capital cost for removing the levee is estimated to be
$2.1 million. This estimate is based on costs for excavating,
loading and hauling 25,000 cubic yards of material at a unit cost
of $22 per cubic yard, and includes 8 polymer applications at a
cost of $70,000 per application. Landfill disposal costs were
not included in this cost estimate, which assumes that the
material will be disposed or reused offsite at minimal cost.
However, in the event that such disposal or reuse is unable to
meet Federal and State requirements, additional costs may be in-
curred for disposal in an appropriate landfill. Once the levee
is removed, no additional monitoring or maintenance will be re-
quired, as this source of contamination will no longer be present
in the Alviso community.
It is possible that some changes may be made to the remedy
as a result of the remedial design and construction processes.
Such changes, in general, would reflect modifications resulting
from the engineering design process.
IX. Statutory Determinations.
The selected remedy will comply with the statutory require-
ments of Section 121 of CERCLA.
Protection of Human Health and the Environment:
The selected remedy will achieve permanent long-term protec-
tion of human health and the environment through removal of the
source of contamination from the Alviso community. The levee
material will be safely disposed of off-site, in a manner that
permanently encapsulates the material and that is protective of
public health and the environment, or in an appropriate landfill.
Implementation of the remedy will not pose unacceptable short
term risks, as long as dust control measures are properly util-
ized.
Compliance with Applicable or Relevant and Appropriate
Requirements:
The selected remedy will comply with all ARARs identified
and described in Section V.
Cost Effectiveness:
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The selected remedy is cost-effective, because it has been
determined to provide overall effectiveness proportional to its
costs. The estimated cost of the selected remedy is $2.1 mil-
lion. The costs for the soil cover remedy previously selected
were estimated to be $2.4 million.
Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum
Extent Practicable:
The selected remedy is in compliance with the statutory man-
date to utilize permanent solutions and alternative treatment-
technologies or resource recovery technologies to the maximum ex-
tent practicable. As explained below, no alternative treatment
technologies are currently practicable for asbestos. Recovery of
asbestos from soils is not appropriate for technological and
practical reasons; because of reduced commercial use, asbestos
has limited recovery or financial value. However, removal of the
ring levee will provide a permanent solution to the extent that
the asbestos-containing ring levee material will be removed from
the community of Alviso, and that permanent encapsulation or
landfill disposal of the levee material off-site will prevent the
emission of asbestos fibers.
Preference for Treatment as a Principal Element:
The selected remedy does not satisfy the statutory
preference for selecting remedies that permanently and sig-
nificantly reduce the toxicity, mobility or volume of the hazard-
ous substances through treatment as a principal element, because
treatment technologies that result in permanent destruction or
alteration of asbestos are not currently practicable. Asbestos
is a natural fibrous mineral that receives its toxicity due to
the form of the fiber. Permanent encapsulation or landfill dis-:
posal of the levee material off-site will protect public health
by preventing the emission of asbestos fibers, but the form of
the fiber will not be altered. Reduction in toxicity or mobility
can only be achieved through destruction or alteration of the
fibers, or by stabilization or solidification of the fibers.
These treatment technologies are not currently practicable and
would be extremely costly.
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APPENDIX I
I. Asbestos Analytical Techniques
There are three commonly accepted analytical techniques used
to measure asbestos. They are:
1) Phase Contrast Microscopy ("PCM") : An optical technique
useful in examining minute dust particles.
2) Polarized Light Microscopy ("PLM"): An optical technique
that uses polarized light to identify minerals.
3) "Transmission Electron Microscopy ("TEM"): A technique using
an electron microscope to achieve extremely high resolution of
asbestos fibers too small to be resolved using optical methods.
A brief description, including the advantages and disad-
vantages of each technique, is presented below.
A. Phase Contrast Microscopy - -
Phase contrast microscopy ("PCM") is a optical microscopy
technique that is commonly used to analyze air samples collected
in the work place (e.g. in enclosed spaces). PCM translates dif-
ferences in the phase of light transmitted or reflected by the
object into differences of intensity in the image. Most of the
available medical studies of asbestos diseases have measured as-
bestos using PCM. This is because PCM was the only technique
available when most of the occupational studies were done. The
method is better suited to analysis of work place air than am-
bient air because in the work place one may expect a higher frac-
tion of asbestos fibers to total particulates.
The PCM technique has three major limitations concerning its
use in the ambient environment. The technique cannot detect
fibers with diameters of less than 0.2 micrometers. Many fibers
in the environment are much smaller than this. Also, PCM can
not distinguish between asbestos fibers and other types of
fibers. Therefore, in the environment, the PCM fiber count may
be completely unrelated to the asbestos fiber content. For these
reasons, it is widely accepted that the PCM method is totally un-
suitable for measurement of asbestos fibers in ambient atmos-
pheres .
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B. Polarized Light Microscopy
Polarized Light Microscopy ("PLM") is the EPA-approved tech-
nique for analysis for bulk insulation samples. The PLM tech-
nique is relatively quick (1/2 hour/sample) and-can be used to:
(1) identify all asbestos types, (2) distinguish between asbestos
and other fibrous and non-fibrous minerals and (3) identify most
non-asbestos components of samples. The resolution capacity of
PLM is 200x to 400x magnification. Another advantage of PLM is
that it can be performed for a relatively low cost.
There are two counting procedures for PLM analysis, the
point counting method and the field comparison method. The point
counting method uses a superimposed grid with 100 pointsr The
operator counts the points where asbestos is present. The point
count method involves the preparation of eight slides, each of
which can be viewed at 100 possible points, to establish the
presence or absence of asbestos at 50 points on each slide. The
result is recorded and reported as area percent based on the num-
ber of positive points. The following format is used for deter-
mination:
Area percent = a/n (100)
where:
a = number of points with asbestos fibers present
n = number of non-empty points counted.
The field comparison method also called "visual estimation"
or the 2-minute method with the stereobinocu-lar light microscope,
is used to quantify a large sample (e.g., 1 ounce) using the
micro- scope at 30-40x. The operator estimates the homogeneity
of the mixture and estimates the percentage of each individual
fibrous component.
The disadvantages associated with PLM include:
o Asbestos content determination done by visual
estimate (field comparison) or point counting is qualitative
or at best, semi-quantitive; concentration is expressed as
the ratio of asbestos to non-asbestos particles or percent
by area.
o Small fiber identification is difficult because certain
optical properties (birefringence and the angle of extinc-
tion) are hard to determine in small fibers.
o The thinnest fibers that can be observed are ap--
proximately 0.4 micrometers in diameter; fibers this small,
cannot usually be identified by mineral type. Sample
preparation methods (grinding) may reduce size of struc-
tures .
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o Highly skilled analysts are required, particularly in
view of the subjective nature of the determinations.
o The "quantitative" limit of detection is 1 area percent.
samples may still contain asbestos in quantities below the
PLM detection limit.
o No standardized sample preparation method currently ex-
ists, which may cause widely varying analytical results be-
tween laboratories.
Using PLM to identify asbestos in soils can be difficult be-
cause soils are subjected to erosion and weathering; asbestos
bundles become-separated and broken into smaller, possibly sub-
optical sizes much more quickly than fiber bundles in relatively
undisturbed insulating materials. Asbestos fibers may also be
dispersed by wind and by seasonal flooding. Therefore, a sizable
fraction of the asbestos fibers in soil could be below optical
resolution. The EPA method for analysis of bulk insulation has
been used as the de facto method for analyzing asbestos in soils,
as no other approved method exists.
C. Transmission Electron Microscopy
Transmission electron microscopy ("TEM,") is the most power-
ful analytical method available for measuring asbestos. TEM has
been used for air, water, or soil analysis. ' It is the preferred
instrumental technique for measuring asbestos in ambient atmos-
phere since it incorporates the most powerful combinations of
identification methods. TEM analysis uses electron microscopy,
at magnifications of 10,000 to 50,000 times, to detect asbestos
structures as thin as 0.2 nanometers in diameter. This is suffi-
cient to identify the thinnest asbestos fibrils under most cir-
cumstances. The transmission electron microscope allows the
operator to locate very small fibers. Two mineral identification
tools, Selected Area Electron Diffraction ("SAED") and Energy
Dispersive X-ray Analyzer ("EDXA") can then be utilized to iden-
tify the mineral type from a single point on the specimen.
The disadvantages associated with TEM include the following:
o No widely accepted TEM method is available for the
analysis of asbestos in soils, making it difficult to
correlate inter-laboratory data. Sample preparation methods
are not standard among workers, making the comparison of
results between sites or laboratories very difficult or
meaningless.
o Analysis requires a minimum of 6 to 8 hours over 2 to 3
-------
days. Highly skilled analysts are required and large dif-
ferences in results can occur due to operator variance.
o TEM analysis is extremely expensive, over 20 times the
per sample cost of optical methods.
o TEM analysis is performed on much smaller sample than PLM
so that obtaining homogeneity during sample preparation is
more critical.
o Typically, total structures are counted. Sample prepara-
tion (i.e., grinding) destroys the structure size distribu-
tion.
Both PLM and TEM sample preparation alters the soil matrix.
This is significant because the sample is dispersed into very
fine particles before it is put onto a filter for analysis.
Since asbestos occurs in clusters and bundles as well as fibers,
the sample preparation process (in the case of soil) can destroy
the structure of those forms and produce a very large number of
individual fibers of small size. Although total fibers are
counted as part of the TEM analysis, these results must be con-
verted to weight percent, using data on length, width, and den- ,
sity. This conversion to mass is necessary due to the sample
preparation grinding process, which artificially increases the
fiber count. How the TEM weight percent compares with air emis-
sions and risk tables has not been standardized by government or
industry. Therefore, interpretation of soil data results rela-
tive to air samples and/or risk charts is very difficult, at
best.
II. Problems With Using Asbestos Data in Quantifying Risk
Although the role of asbestos as a cause of cancer is clear,
the ways in which fibers cause disease are not well understood,
and this has complicated efforts to measure asbestos success-
fully. Asbestos researchers have not agreed upon which attributes
of asbestos are important to measure to assess risk, including
size and shape of individual fibers, number of fibers, total mass
of fibers, inclusion of asbestos bundles, clusters, and matrix
debris in the fiber count, and asbestos mineralogical type. For
example, most researchers think that longer, thinner asbestos
fibers, (those longer than 5 microns in length with an aspect
ratio greater than 3 to 1) are more carcinogenic, i.e., the
"Stanton Hypothesis". However, other researchers question this
approach, suggesting that both long and short fibers may be
biologically active. In addition to fiber dimension, surface
chemistry of the asbestos fiber may play a role in causing dis-
ease. Further, there is disagreement whether mineral type is a
factor in disease causation. Some would argue that chrysotile
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asbestos may partially dissolve in weakly acidic environments,
facilitating fiber clearance from the lung. However. EPA's view
is that all asbestos mineral types are equally carcinogenic.
To compound the problem, analysis of ambient samples for as-
bestos is much more difficult than occupational or work place
samples, because the concentration of asbestos in the environment
may be much lower. Asbestos fibers found in ambient air may be
too short and thin to be detected by conventional microscopes,
and may be agglomerated with other particulate matter so that
they are masked or hidden. Further, although EPA has attempted
to standardize asbestos analytical techniques, differences in
sample handling, preparation, instrument capabilities, operator
proficiency, and counting procedures make it extremely difficult
to compare results from different laboratories. In short, ac-
curate measurement of asbestos is impeded by many factors,
greatly complicating any estimates of environmental risk. For
this reason clean up levels have been established using the best
available analytical methods. The following discussion sum-
marizes the rationale behind choosing the one area percent by PLM
clean up level.
III. Clean Up Goals for the South Bay Asbestos Area Site
Problems with asbestos analytical techniques make estab-
lishing health-based clean up levels very difficult. As men-
tioned above, the clean up level of one area percent by PLM has
been chosen because it is the best available.analytical tech-
nique. This is further evidenced by the fact that EPA chose
this method (PLM) for use in the Asbestos Hazard Emergency
Response Act ("AHERA"). AHERA specifies that th« EPA approved
PLM method be used to measure asbestos levels in bulk insulation
samples. EPA has promulgated the one area percent clean up level
for the South Bay Asbestos Area site because one area percent is
the generally accepted detection limit for asbestos in soil using
PLM. One area percent by PLM has also been used in the past as
an action level in emergency response situations.
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Responses to Ring Levee Comments
from the
February 15, 1989 Public Meeting
A few comments concerning the ring levee were made at the
February 15, 1989 Public Meeting on the Proposed Plan for ad-
dressing asbestos contamination in the remainder of the com-
munity. The meeting transcript may be found in Appendix A of the
Responsiveness Summary for the Remedial Investigation/Feasibility
Study and the Proposed Plan, dated September 25, 1989. The ring
levee comments are addressed below:
1. Comment:
One community member asked why EPA had planned to cap the
levee if the prevailing winds were not the cause of asbestos
releases, (meeting transcript, p. 28)
Response:
EPA originally proposed remediation for the ring levee be-
cause children and adults frequently walk, ride bicycles, picnic
and play on the levee, and they may be exposed to asbestos.
2. Comment:
One community member commented that levee removal would
create more flooding problems if the levee is not replaced.
Another commented that the community did want a levee, but not an
asbestos levee, (meeting transcript, pp. 80, 90)
Response:
According to the City of San Jose, a flood control study of
the ring levee conducted by the City in 1988 concluded that the
levee provides only short term flood protection. The Santa Clara
Valley Water District, under a grant from the U.S. Army Corps of
Engineers, is currently constructing levees on the Coyote Creek,
which will provide permanent flood protection for Alviso.
The ring levee will not be completed until after the Coyote Creek
project is completed.
3. Comment:
One community member asked if EPA will be on site when the
levee is removed to ensure that dust requirements are met.
(meeting transcript p. 84)
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Response:
The City of San Jose and Raisch Company will be required to
submit plans for dust control during the removal activities,
which must be approved by EPA. EPA will oversee the removal ac-
tivities to ensure that dust suppression techniques are carried
out properly.
4. Comment:
One community member was concerned with liability issues
in the event of flooding after the levee is removed; asked if
EPA's agreement with the City covered flood liability, and asked
if there would be legal recourse against the City of San Jose or
EPA if flooding occurred after removal of the levee, (meeting
transcript p. 84)
Response:
The Santa Clara Valley Water District is the agency respon-
sible for flood control in this region. The City of San Jose has
informed EPA that the City's flood control study conducted in
1988 showed that the ring levee Would be ineffective in prevent-
ing a major flood, but the Coyote Creek improvements currently
under construction will be far more effective in controlling fu-
ture flooding. To ensure continual flood protection for Alviso,
the amended Record of Decision and EPA's agreement with the City
and Raisch will provide that the ring levee will not be removed
until after the Coyote Creek improvements have been completed.
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