PB97-963113
EPA/541/R-97/037
November 1997
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
San Fernando Valley (Area 1),
Burbank Operable Unit
Los Angeles, CA
2/12/1997
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SFUND RECORDS CTR
2166-OS336
San Fernando Valley Superfund Site
Burbank Operable Unit
Second Explanation of Significant Differences
to the
Record of Decision
United States Environmental Protection Agency
Region IX - San Francisco, CA
February 12, 1997
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SECOND
EXPLANATION OF SIGNIFICANT DIFFERENCES
DECLARATION
SITE NAME AND LOCATION
San Fernando Valley Area 1
Burbank Operable Unit
Los Angeles County, California
I. Statement of Basis and Purpose
This decision document presents the Second Explanation of
Significant Differences (ESD2) to the interim remedial action
selected by the Burbank Operable Unit (Burbank OU) Record of
Decision (ROD) signed June 1989. The Burbank OU ROD was
previously modified by an Explanation of Significant Differences
dated November 1990 (ESDI). Additional changes to the remedy
were made in a 1992 Consent Decree, which was approved by the
Central District of California federal court. ESD2 has been
developed in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act (42 U.S.C. Section 9601
et. seq.) and the National Contingency Plan (40 C.F.R. Section
300 et. seq.).
^
II. Description of the Selected Remedy in the ROD and ESDI
The Burbank OU ROD selected the interim remedy for an area of
groundwater contamination, located within the San Fernando Valley
Area 1 Superfund Site, which encompasses wellfields which were
operated by the City of Burbank prior to being shut down as a
result of the contamination. The ROD selected extraction of
contaminated groundwater, treatment by air or steam stripping,
and use of the treated water as a public water supply by the City
of Burbank. The interim remedy was estimated to cost $69 million
over 20 years (in 1989 dollars).
The ROD selected as the interim remedy the extraction and
treatment of groundwater at a rate of 12,000 gallons per minute
(gpm). This was considered to be the extraction rate necessary
to hydraulically control, i.e. to prevent the spreading of,
groundwater at concentrations of 100 parts per billion (ppb) of
trichloroethylene (TCE) and 5 ppb of perchloroethylene (PCE).
Extraction wells were to be placed in locations which would
control plume migration while initiating aquifer restoration.
The treatment technology specified was either air stripping or
steam stripping, with off-gas control.
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The ROD states that the treated water must meet all existing
federal and state Maximum Contaminant Levels (MCLs) and State
Action Levels (SALs). It also states that the water must meet
all drinking water treatment technology requirements. The ROD
states a preference for delivering the treated water to the City
of Burbank's distribution system for use as a public water
supply. Using the treated water in this manner was considered
preferable to discharging the water to waste because it
represents a beneficial use of the groundwater resource in a
water-poor region.
III. Summary of ESDI
ESDI clarified and superseded certain parts of the Burbank OU
ROD, as follows.
Based on new information regarding the occurrence of nitrate in
the groundwater (nitrate levels turned out to be higher than
anticipated), it became clear that additional treatment measures
would be required in order for the extracted and treated
groundwater to be used as a public water supply. EPA decided to
require blending of the extracted and treated Burbank OU
groundwater with a water supply lower in nitrates, such that the
MCL is achieved in water served to the public.
The nitrate blending requirement increased the total amount of
water produced by the interim remedy. The total amount to be
produced was high enough that the possibility was raised that the
City of Burbank would not be able to accept the total quantity of
water produced at the Burbank OU. Other local water purveyors
were unwilling to commit to accept excess water produced by the
Burbank OU treatment plant. Therefore, in order to ensure that
the interim remedy would continue to extract contaminated
groundwater at the intended capacity, EPA decided to require
reinjection of any excess water.
EPA clarified that the interim remedy could be designed,
constructed, and operated in phases. Phasing the project allows
for initial completion of a portion of the total extraction
wellfield and treatment plant capacity. Operation of this first
phase of the project allows collection of data on aquifer
response and treatment plant efficiency. This data helps the
design engineer to optimize the design of the following project
phases, and helps to optimize overall groundwater containment and
treatment efficiency for the project.
EPA clarified statements in the ROD pertaining to containment of
groundwater containing TCE at 100 ppb and PCE at 5 ppb. These
levels are not treatment goals to be attained in groundwater, but
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are to be used in designing the containment area to be developed
by the extraction wellfield.
Because of the addition of reinjection as a component of the
project, ARARs pertaining to reinjection of extracted and treated
groundwater were identified. Specifically mentioned was the
"Statement of Policy with Respect to Maintaining High Quality of
Waters in California," which requires that reinjected water not
degrade existing water quality.
The additional cost due to ESDI changes in the interim remedy
were estimated at $8.8 million over 20 years (in 1990 dollars).
IV. Summary of Additional Significant Differences (ESD2)
Based on additional study of the local (Burbank OU) groundwater
system by Lockheed Martin, and by EPA's consultant CH2M Hill, EPA
has concluded that an extraction rate of 9,000 gpm results in
substantially the same level of groundwater containment as an
extraction rate of 12,000 gpm. Overall costs are reduced at the
lower extraction rate, because the need to construct and operate
expensive reinjection facilities is eliminated. Cost
effectiveness is improved because the lower extraction rate makes
it less likely that the upper groundwater zone will become de-
watered, and thus will allow EPA to achieve its goal of
preferentially pumping the most contaminated zones. Based on
these factors, EPA has lowered the* interim remedy extraction rate
to 9,000 gpm.
EPA has decided to eliminate reinjection as a requirement based
on projections that there will essentially be no excess water at
the revised groundwater extraction rate. The City of Burbank can
substantially accept, and has committed to accept, an average of
9,000 gpm from the interim remedy facilities.
Due to elimination of reinjection from the project, the Burbank
OU groundwater extraction rate will not be a continuous 9,000
gpm. The instantaneous extraction rate will fluctuate with the
City of Burbank's water demand. In recognition of the likelihood
that it will not be possible to extract groundwater at a rate of
9,000 gpm, twenty-four hours a day, three hundred and sixty-five
days a year, EPA is specifying that the new extraction rate will
be achieved as an average rate, not an instantaneous rate.
EPA has also decided to suspend the 9,000 gpm extraction rate
requirement during times when nitrate levels in the extracted
groundwater exceed 50 mg/1 as nitrate. The ability to maintain
an annual extraction rate of 9,000 gpm is not only dependent on
the City of Burbank's water demand, but also upon nitrate
concentrations in the extracted groundwater. It is possible that
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these concentrations may rise high enough such that, during
periods of low water demand, it is not possible to extract an
average of 9,000 gpm and also meet the nitrate MCL. EPA's
analysis suggests that even under the worst case scenario for
nitrates, an average of 8,500 gpm would be pumped. EPA believes
the interim remedy will continue to be protective of human health
and the environment even at this slightly reduced groundwater
extraction rate, which, if it occurs, will only occur on an
occasional basis.
EPA estimates that changes to the interim remedy effected by ESD2
will reduce implementation costs by $49 million (1995 dollars).
Further, the City of Burbank holds a public water supply
operating permit, issued by the California Department of Health
Services. This permit has been amended to cover operation of the
Burbank OU treatment facilities. The requirements of this permit
will govern off-site requirements for drinking water
protectiveness.
V. Declaration
The selected remedy, as modified by this BSD, is protective of
human health and the environment, attains federal and state
requirements that are applicable, or relevant and appropriate, to
this interim remedial action, and is cost-effective. This remedy
satisfies the statutory preference* for remedies that employ
treatment which permanently and significantly reduces the volume,
toxicity or mobility of the hazardous substances as a principal
element. It also complies with the statutory preference for
remedies that utilize permanent solutions and alternative
treatment technologies or resource recovery technologies to the
maximum extent practicable. As part of the remedy, groundwater
monitoring will be conducted to track contaminant levels at the
Burbank Operable Unit and to monitor the performance of the
extraction and treatment system in order to ensure adequate
protection of human health and the environment.
Keith Takata Date
Director, Superfund Division
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San Fernando Valley Area 1, Burbank Operable Unit
SECOND EXPLANATION OF SIGNIFICANT DIFFERENCES
February 12, 1997
I. Introduction
On June 30, 1989, the U.S. Environmental Protection Agency (EPA)
signed a Record of Decision (ROD) for the San Fernando Valley
Area 1 Superfund Site, Burbank Operable Unit (Burbank OU). On
November 21, 1990, EPA signed an Explanation of Significant
Differences (ESDI) modifying the interim remedial action selected
in the ROD. The purpose of this Second Explanation of
Significant Differences (ESD2) is to explain additional
modifications to the interim remedial action.
Under Section 117 of the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) of 1980, as amended by
the Superfund Amendment and Reauthorization Act of 1986, and
pursuant to 40 C.F.R. Sec. 300.435 (c) (2) (i) (55 Fed. Reg. 8666,
8852 (March 8, 1990)), EPA is required to publish an Explanation
of Significant Differences when significant (but not fundamental)
changes are made to a final remedial action plan as described in
a ROD.
This document provides a brief background of the Site, a summary
of the remedy selected in the Burbank OU ROD, a summary of
changes made to the remedy by ESDI, a description of the changes
to the remedy EPA is making in this ESD2 (including how the
changes affect and better refine the remedy selected in the ROD),
and an explanation of why EPA is making these changes.
EPA is issuing ESD2 in order to take into account technical data
received after ESDI was signed in November, 1990. The changes
are: (1) Based on additional study of the local (Burbank OU)
groundwater system, EPA has concluded that an extraction rate of
9,000 gallons per minute (gpm) results in substantially the same
level of groundwater containment as an extraction rate of 12,000
gpm. Therefore, the interim remedy extraction rate has been
reduced to 9,000 gpm; (2) EPA is specifying that the new
extraction rate will be achieved as an average rate, not an
instantaneous rate; (3) EPA has decided to eliminate reinjection
as a requirement based on projections that, on an annual basis,
there will be no excess water at the revised groundwater
extraction rate; and, (4) EPA has decided that the specified
average extraction rate need not be met during times when nitrate
levels in the extracted groundwater exceed 50 mg/1, because under
this circumstance a greater quantity of blending water will be
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required, leaving the City of Burbank less capacity to accept
extracted groundwater for use as a public water supply.
ESD2 and the supporting documentation will become part of the
Burbank OU Administrative Record. Copies of the Administrative
Record have been placed at the following locations:
City of Burbank Public Library
110 North Glenoaks Boulevard
Burbank, CA 91502
818-953-9737
City of Glendale Public Library
222 East Harvard Street
Glendale, CA 91205
818-956-2027
II. Background
A. Site background and description
The following gives a brief background of the Burbank OU and a
short summary of the remedy selected in the ROD and modified by
ESDI. Further background information can be found in the ROD
(dated June 30, 1989), and in ESDI (dated November 20, 1990), as
well as in other documents in the Burbank OU Administrative
Record. »
In June 1986, EPA evaluated the threat posed by groundwater
contamination at a number of water supply wellfields within the
San Fernando Valley and Verdugo groundwater basins. The chief
contaminants of concern are trichloroethylene (TCE) and
perchloroethylene (PCE). As a result of its investigation, EPA
designated four wellfield areas as National Priorities List (NPL)
sites. EPA is managing the four sites as a single project
consistent with CERCLA Section 104(d)(4).
The San Fernando Valley Groundwater Basin has historically been
an important source of drinking water for the Los Angeles
metropolitan area, including the City of Burbank. The
groundwater basin provides enough water to serve approximately
600,000 residents.
Groundwater extracted from the basin is especially important
during years of drought. Due to contamination by volatile
organic chemicals (VOCs), including TCE and PCE, beneficial use
of the groundwater resource has been partially lost. Surface
water supplies have replaced the lost resource, but are costly,
and may not be available in the future due to periodic drought
conditions and the potential for changing water rights policy.
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The Burbank OU is located within the San Fernando Valley
groundwater basin and encompasses wellfields which were operated
by the City of Burbank prior to being shut down as a result of
contamination. The Burbank OU was specifically developed to
address this areal extent of groundwater contamination.
The City of Burbank's production wells have been shut down since
the early 1980s because of the presence of TCE and PCE in
concentrations exceeding federal and state Maximum Contaminant
Levels (MCLs). Consequently, the city purchases close to one
hundred percent of its water from the Metropolitan Water District
of Southern California, which supplies surface water imported
from outside the San Fernando basin. (The city does operate a
granular activated carbon groundwater extraction and treatment
plant during parts of the year, but the contribution of this
plant toward meeting the overall water demand is small.)
B. Selected remedy as modified by ESDI
The Burbank OU ROD selected the interim remedy for an area of
groundwater contamination generally located within the San
Fernando Valley Area 1 Superfund Site. The ROD selected
extraction of contaminated groundwater, treatment by air or steam
stripping, and use of the treated water as a public water supply
by the City of Burbank. The interim remedy was estimated to cost
$69 million over the 20 year planned length of the interim
remedy. ESDI added the requirement to blend the extracted,
treated, water with a lower nitrate source in order to meet
nitrate MCLs. ESDI also added the requirement for reinjection of
excess water that the city could not accept due to water demand
limitations. The changes to the interim remedy caused by ESDI
were estimated to cost $8.8 million, raising the total estimated
project cost to $77.8 million (in 1989/1990 dollars).
Based on analyses conducted by the Los Angeles Department of
Water and Power, through their consultant James M. Montgomery, in
the Burbank OU Feasibility Study, the ROD specified that
groundwater would be extracted and treated at a rate of 12,000
gpm. This rate was considered necessary in order to control
plume migration and to initiate aquifer restoration. The 12,000
gpm rate was projected to hydraulically contain groundwater
having a concentration of 100 parts per billion (ppb) of TCE and
5 ppb of PCE. ESDI clarified that these levels are not treatment
goals to be attained in groundwater, but are to be used in
designing the containment area to be developed by the extraction
wellfield.
The ROD states that the treated water must meet all existing
federal and state MCLs and State Action Levels (SALs). It also
states that the water must meet all drinking water treatment
technology requirements. The treated water is being delivered to
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the City of Burbank's distribution system for use as a public
water supply. Use of the treated water in this manner is
considered preferable to discharging the water to waste because
it restores the groundwater resource to beneficial use.
With respect to meeting drinking water standards, ESDI concluded
that, based on new information suggesting high nitrate levels in
the groundwater, additional measures were required to meet the
MCL for nitrate in the extracted and treated water. EPA decided
to require blending of the extracted and treated groundwater with
a water supply lower in nitrates, such that the MCL is achieved
in water served to the public.
Addition of the nitrate blending requirement raised the
possibility that the City of Burbank would not be able to accept
the total quantity of water produced by the interim remedy. This
is because nitrate blending raises water production, from the
initially anticipated rate of 12,000 gpm, to a rate as high as
24,000 gpm. Under ESDI, EPA decided to require reinjection of
any excess water, or water the City of Burbank could not use as a
public water supply due to insufficient demand. EPA also
identified Applicable or Relevant and Appropriate Requirements
(ARARs) pertaining to reinjection of extracted and treated
groundwater, specifically, the "Statement of Policy with Respect
to Maintaining High Quality of Waters in California," which
requires that reinjected water not degrade existing water
quality.
\
Under ESDI, EPA also clarified that the interim remedy could be
designed, constructed, and operated in phases. Phasing the
project allows for initial completion of a portion of the total
extraction wellfield and capacity treatment plant capacity.
Operation of this first phase of the project allows collection of
data on aquifer response and treatment plant efficiency. This
data helps the design engineer to optimize the design of the
following project phases, and helps to optimize overall
groundwater containment and treatment efficiency for the project.
Portions of the Burbank OU ROD and ESDI have already been
implemented through a 1992 Consent Decree and a Unilateral
Administrative Order. EPA also made additional operational
changes in the interim remedy in the 1992 consent decree, which
was approved by the Central District of California federal court.
The 1992 consent decree, captioned United States of America v.
Lockheed Corporation et al., Civil Action No. 91-4527 MRP(Tx), is
included in the Administrative Record.
Under the Consent Decree, Lockheed Martin and the City of Burbank
have constructed the first phase of the interim remedy. Under
the Unilateral Administrative Order, a group of parties
associated with six other Burbank facilities have constructed the
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blending facility, the purpose of which is to reduce nitrates in
the extracted, treated groundwater. The first phase of the
interim remedy was completed and became operational in January
1996. The first phase consists of groundwater extraction and
treatment at a rate of 6,000 gpm, blending with Metropolitan
Water District water, and use of the treated, blended water as a
public water supply.
III. Summary of Significant Differences
ESD2 provides for the following changes to the interim remedy:
1) EPA has lowered the interim remedy extraction rate to 9,000
gpm. Based on additional study of the local (Burbank OU)
groundwater system during the Remedial Design phase, EPA has
concluded that an extraction rate of 9,000 gpm results in
substantially the same level of groundwater containment as an
extraction rate of 12,000 gpm. Cost effectiveness is improved at
the lower extraction rate, not only due to the reduced cost of
pumping less water, but because the need to construct and operate
expensive reinjection facilities is eliminated. In addition, the
lower extraction rate makes it less likely that the upper
groundwater zone will become de-watered, and thus will allow EPA
to achieve its goal of preferentially pumping the most
contaminated zones.
2) EPA has decided to eliminate reinjection as a requirement.
This decision is based on projections that, under existing
aquifer conditions, there will be no excess water (i.e. water
that cannot be used by the City of Burbank as a public water
supply) produced at the revised groundwater extraction rate. The
City of Burbank has committed to accept an annual average of
9,000 gpm from the interim remedy facilities.
3) EPA is specifying that the 9,000 gpm extraction rate will be
achieved as an average rate, not as an instantaneous rate. Due
to elimination of reinjection, the instantaneous rate will
fluctuate with the City of Burbank's water demand. EPA
recognizes that it will not be possible to extract groundwater at
a rate of 9,000 gpm, twenty-four hours a day, three hundred and
sixty-five days a year. However, EPA's analysis suggests that
under the worst case scenario for nitrates, groundwater can be
extracted at a minimum rate of 8,500 gpm. EPA believes
protectiveness of human health and the environment is maintained
even at this slightly reduced rate, which, if necessary, will
only be necessary on an occasional basis. In order to maximize
the amount of groundwater pumped, EPA has decided to count
groundwater extraction from the city's granular activated carbon
treatment plant toward the 9,000 gpm average rate. This
wellfield will most likely be used by the city during the summer
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to meet peak water demand. The City of Burbank has agreed to
maximize its use of treated groundwater. These decisions and
agreements are to be included in a second consent decree between
EPA, the city, and numerous Burbank parties.
4) EPA has decided to suspend the 9,000 gpm extraction rate
requirement during times when nitrate levels in the extracted
groundwater exceed 50 mg/1 as nitrate. This decision is being
made to ensure that under no circumstances will the MCL for
nitrate be exceeded in the treated water. The ability to
maintain an annual extraction rate of 9,000 gpm is not only
dependent on the City of Burbank's water demand, but also upon
nitrate concentrations in the extracted groundwater and in the
blending water. It is possible that these concentrations may
rise high enough such that, during periods of low water demand,
it is not possible to extract an average of 9,000 gpm and also
meet the nitrate MCL. However, as mentioned in the above
paragraph, the City of Burbank has agreed to maximize its use of
treated groundwater.
Lockheed Martin has estimated that changes to the interim remedy
effected by ESD2 will reduce implementation costs by 49 million
dollars (1995 dollars), and EPA is in agreement with this
estimate.
IV. Explanation and Detailed Description of Changes and
Clarifications ^
After the ROD and ESDI were signed, EPA received and reviewed new
data' from its Alternative Remedial Contracting Strategy (ARCS)
contractor CH2M Hill, from the City of Burbank, and from the
Lockheed Martin Corporation, regarding the Burbank OU groundwater
system. This new information included both data collected in the
field (from groundwater monitoring wells) and the output from
computer modeling exercises. Reports and technical memoranda
were generated compiling this data, which project that the
implementation of ESD2 will not reduce the protectiveness of the
Burbank OU interim remedy. Thus, EPA's conclusion in the ROD and
ESDI that the interim remedy is protective of human health and
the environment has not changed. The new and existing technical
information that EPA relied upon to prepare ESD2 is identified in
the discussion which follows, and this information can be found
in the Burbank OU Administrative Record.
A. Background
Based on this new information, EPA has concluded that a lower
pumping rate than originally projected will result in the desired
degree of containment of the VOC contaminant plume in the
vicinity of the Burbank OU. This projection results from an
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improved ability on EPA's part to predict aquifer response to
pumping, made possible because real operating data is now
available from Phase 1 of the Burbank OU interim remedy, which
includes a 6,000 gpm groundwater extraction wellfield. In
addition, the local groundwater flow models designed by CH2M Hill
and by Lockheed Martin have undergone additional improvement and
verification since the ROD was written. Results from both models
predict that a 9,000 gpm extraction rate achieves the goals of
the ROD.
EPA believes it is important to implement this change not only
because it is based on sound scientific analysis, but also
because of cost savings to the project. Reducing the pumping
rate allows for elimination of costly reinjection facilities
required under ESDI. The lower pumping rate also ensures that
EPA will be able to pump from the most contaminated zones of the
aquifer without dewatering the aquifer.
EPA, with the assistance of CH2M Hill, the City of Burbank, and
Lockheed Martin, performed the following analysis in reaching
these conclusions.
B. Options
While CERCLA Section 117 (c) and 40 C.F.R. Section
300.435 (c) (2) (i) merely require an explanation of significant
differences and the reason for these differences, ESD2 sets out
in detail four options regarding Che rate of groundwater
extraction, along with EPA's analysis of these options. The four
options are as follows:
1. Extraction and treatment of an annual average of 6,000 gpm
of groundwater from the existing Phase 1 Burbank OU wellfield,
with use of the treated water by the City of Burbank (this phase
of the project is currently in operation; therefore, if Option 1
were selected, no further construction would be required at the
Burbank OU);
2. Extraction and treatment of an annual average of 9,000 gpm
of groundwater from the existing Phase 1 Burbank OU wellfield,
and the planned Phase 2 wellfield, with use of the treated water
by the City of Burbank/
3. Extraction and treatment of an annual average of 12,000 gpm
of groundwater from the existing Phase 1 and proposed Phase 2 and
Phase 3 Burbank OU wellfields, with use of the treated water by
the City of Burbank, with conveyance of excess water to other
purveyors;
4. Extraction and treatment of an annual average of 12,000 gpm
of groundwater from the existing Phase 1 and proposed Phase 2 and
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Phase 3 Burbank OU wellfields, with use of the treated water by
the City of Burbank, and reinjection of excess water (this is the
option selected by the ROD as modified by ESDI) .
C. Analysis of options
The four options presented above were compared with each other
based on the nine criteria listed and explained in the National
Contingency Plan (NCP) , 40 C.F.R. Section 300 .430 (e) (9) (iii) .
The nine criteria and the results of the comparison of the
options are presented in this subsection. The nine criteria are
as follows:
1. compliance with ARARs
2 . overall protection of human health and the
environment
3. short-term effectiveness in protecting human
health and the environment
4. long-term effectiveness and permanence in
protecting human health and the environment
5. reduction of toxicity, mobility, and volume
of contaminants
6. technical and administrative feasibility of
implementation
7. capital and operation and maintenance costs
8 . state acceptance
9 . community acceptance
\
An analysis of the four options in terms of the above criteria
follows .
1.
Compliance with ARARs
The Burbank OU ROD recognizes that chemical-specific ARARs for
the groundwater itself will be addressed in the final remedy.
The remedial action adopted pursuant to the ROD, ESDI, and ESD2,
is an interim action; therefore, chemical -specif ic ARARs for the
groundwater contaminant plume do not apply to the activities
taken pursuant to the ROD, ESDI, and ESD2 .
However, for each of the four options being considered, drinking
water standards, including state and federal MCLs, source water
monitoring protocols, and treatment technology requirements, must
be met. The existing treatment plant designed under Phase 1 has
been shown to meet these standards during operation at flows up
to 6,000 gpm. Option 1 is essentially Phase 1 of the Burbank OU
interim remedy, which EPA has previously concluded meets drinking
water ARARs .
The Phase 1 Burbank OU treatment plant is currently being
operated to meet all standard state drinking water requirements
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and several special conditions, as specified in the public water
supply operating permit issued to the City of Burbank by the
California Department of Health Services (DHS). Since the
treatment plant was designed with excess capacity, and can
produce up to 9,000 gpm with no loss in treatment efficiency, EPA
is confident that Option 2 will also meet drinking water ARARs.
Options 3 and 4 would require modification to the treatment
plant, but EPA is also confident that such modifications could be
performed such that these standards would be met.
The treatment standards applicable to the Burbank OU treatment
system were initially established in the ROD. The ROD required
that the treatment system meet MCLs for all constituents (other
than nitrates). Because water from the Burbank OU treatment
system is conveyed offsite for use as a public water supply, and
applicable drinking water standards may change, the consent
decrees governing operation of the treatment plant recognize that
EPA may identify requirements promulgated after the date of the
ROD as ARARs in accordance with section 300.430 (f) (1) (ii) (B) (1)
of the NCP. That section requires attaining (or waiving)
requirements promulgated after the date of the ROD where
necessary to protect human health or the environment. This BSD
does not change the treatment standards for operation of the
treatment plant.
With respect to groundwater reinjection, ARARs include the
California Regional Water Quality Control Board's (RWQCB) Non-
degradation Policy, and Resource Conservation and Recovery Act
(RCRA) Section 3020. The only option studied which involves
reinjection is Option 4.
Any water reinjected on-site must meet all action-specific ARARs
for reinjection. The reinjection must meet the "Statement of
Policy With Respect to Maintaining High Quality of Waters in
California," which requires that reinjected water not
unreasonably degrade existing water quality. Nitrates are of
concern with respect to reinjection; to avoid degradation, water
from the Burbank OU treatment plant would have to be reinjected
into an area of the aquifer containing as high or higher nitrate
concentrations.
RCRA Section 3020 provides that the ban on the disposal of
hazardous waste into a formation which contains an underground
source of drinking water shall not apply to the injection of
contaminated groundwater into the aquifer if: (i) such
reinjection is part of a response action under CERCLA; (ii) such
contaminated groundwater is treated to substantially reduce
hazardous constituents prior to such reinjection; and (iii) such
response action will, upon completion, be sufficient to protect
human health and the environment.
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Compliance with reinjection ARARs could be problematic for
implementation of Option 4 due to high nitrate levels in the
extracted and treated groundwater, and limited areas of the
aquifer available for reinjection based on ARARs criteria.
Based on consideration of drinking water ARARs, Options 1, 2, and
3 are considered equivalent. Option 4 is considered less
favorable than Options 1-3 due to potential difficulties in
meeting reinjection ARARs.
2. Overall protection of human health and the environment
Options 1-4 are all protective of human health and the
environment. In each case, direct threat of human contact with
contaminated groundwater has been minimized. Extracted
groundwater is being treated to meet drinking water standards
before being served to the public. Therefore, the selection of
any of the four options for interim remedial action would result
in no change in protection to human health and the environment
from that achieved under the interim remedial action established
in the ROD and ESDI.
Options 1-4 all inhibit the spreading of the VOC plume to
downgradient wellfields, and along with federal and state source
water monitoring requirements minimize the likelihood that
contaminated water from downgradient wells would be served to the
public. As far as the degree of overall containment is
concerned, based on studies performed by CH2M Hill and Lockheed,
EPA believes that protection of the aquifer is adequate under
Options 2, 3, and 4, and may be adequate under Option 1. This
issue is discussed further in the section on long-term
protectiveness below.
Options 1-4 all protect the environment from contact with
contaminated groundwater. Under all four options, extracted
groundwater is being treated and used as a public water supply
and is not being discharged to the land surface. Option 4
differs from the other three options in that it requires
reinjection of excess water. As long as reinjection ARARs are
followed, Option 4 will not result in degradation of groundwater
quality.
3. Short-term effectiveness in protecting human health and the
environment
The analysis regarding short-term effectiveness of the Burbank OU
interim remedy in protecting human health and the environment
does not differ from the above analysis of overall protection of
human health and the environment. Options 1-4 are all protective
in the short-term. Phase 1 of the Burbank OU project has already
been constructed, and treated groundwater is being provided to
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the residents of the City of Burbank without negative impact;
therefore, Option 1 would not produce additional short-term
impacts.
Options 2-4 would require additional construction activity. The
only potential additional short-term impact to human health and
the environment would be limited to minor, standard, construction
concerns such as exposure to wind-blown dust, and noise impacts.
The well drilling activities necessitated under these three
options would be limited to one to two months in duration, would
produce very little airborne dust, and noise would be limited to
daytime hours. Option 2 would not produce any other short-term
impacts. Options 3 and 4 would require an upgrade of the Burbank
OU treatment plant, but this would consist of modifications to an
existing plant and would not require significant excavation or
earth moving activities, merely the addition or modification of
existing physical components to the plant.
EPA believes any construction impacts would be minimal, and that
Options 1-4 are all protective of human health and the
environment in the short-term.
4. Long-term effectiveness and permanence in protecting human
health and the environment
Options 1-4 would all maintain reliable protection of human
health and the environment over time. Minor differences arise in
the permanence of the various options. Since this is an interim
remedial action, and the action itself is not considered
permanent, permanence has not been considered a major factor in
this evaluation.
However, in ranking the options with respect to permanence, EPA
has evaluated to what degree they would contribute to aquifer
restoration. Option 2 results in the greatest mass, removal of
PCE and TCE, suggesting that the combination of pumping rate and
location of extraction wells is optimized under this alternative.
The other options result in a similar degree of mass removal,
with differences of only a few percent. This suggests that the
20 year period of groundwater extraction, which is not changed by
this BSD, may be the controlling factor for mass removal. One
unknown factor in this analysis is how much mass will continue to
enter the groundwater system over the 20 year period of time.
The final remedy will attempt to assess this effect and will
attempt to address permanence in a more thorough analysis.
A comparison of mass removal for Options 1-4 over 20 years is
presented below. These figures derive from an analysis performed
by Lockheed Martin Corporation and reviewed by EPA, and EPA's
consultant CH2M Hill. (See the Administrative Record: document
entitled Evaluation of Extraction Scenarios for the BOUf dated
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March 20, 1995, prepared by Hydro-Search, Inc.) The comparison
of percent removal uses as a baseline the Burbank OU groundwater
plume as defined by the 5 ppb contour line. Percent removal
refers to the percentage of the mass within the 5 ppb contour
which is removed by the Burbank OU extraction wells over the 20
year projected length of the interim remedy.
As noted, the amount of mass removed is greater at a 9,000 gpm
extraction rate (Option 2) than at a 12,000 gpm extraction rate
(Option 4). This is due to the need to meet reinjection ARARs
for nitrates under Option 4. The locations where reinjection
wells may be placed to meet ARARs are not favorable for mass
removal, because under Option 4, the treated water must be
reinjected in an area close to the extraction wells. The
reinjected water actually displaces and dilutes contaminated
water such that overall removal efficiency for TCE and PCE
decreases.
Table 1 - Mass Removal Over Twenty Years
% mass PCE removed % mass TCE removed
Option I1
Option 22
Option 33
Option 44
89
92
91
88
73
78
78
75
The only other long-term protectiveness issue relates to air
emissions from the Burbank OU treatment plant. The off-gas from
the plant's aeration towers contains TCE and PCE molecules which
have been stripped from the groundwater. Although this off-gas
is treated with the use of air-phase granular activated carbon, a
small quantity of TCE and PCE (less than 1% of the total present
in the off-gas) is released to the atmosphere at an. elevation of
approximately sixty feet above the ground surface. The South
Coast Air Quality Management District has reviewed the emission
levels and found them well within ARARs for air emissions. EPA
believes that emissions from Options 1-4 will not negatively
impact human health and the environment, due to the low level of
emissions, and due to their emission at a significant height
above ground surface, away from people.
16,000 gpm pumping rate, no reinjection
29,000 gpm pumping rate, no reinjection
312,000 gpm pumping rate, no reinjection
412,000 gpm pumping rate, with reinjection
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Nonetheless, Options 1-4 can be ranked in terms of overall
emissions. The lower the groundwater extraction rate, the lower
the rate of TCE and PCE removal, and the lower the rate of TCE
and PCE emissions. Option 1 at a groundwater extraction rate of
6,000 gpm results in the least air emissions. Option 2 performs
the next best in this respect. Options 3 and 4 result in
slightly higher emissions.
5. Reduction of toxicity, mobility, and volume of contaminants
As stated above, EPA has evaluated to what degree the four
options will contribute to mass removal. Mass removal of
contaminants relates very closely to reduction in toxicity and
volume of contaminants in the groundwater. Based on EPA's
evaluation, all four options would result in similar degrees of
reduction in toxicity and volume.
An assessment has also been made regarding the degree of
hydraulic control Options 1-4 would exert over the groundwater
contamination (Evaluation of Extraction Scenarios for the SOU,
dated March 20, 1995, prepared by Hydro-Search). The degree of
hydraulic control achieved relates very closely to reduction in
mobility of the contaminants. The following comparison of
hydraulic control is made based upon the groundwater plume as
defined by the 5 ppb contour line (percent control refers to the
percentage of the area within the 5 ppb contour which is
contained, i.e. which does not move downgradient):
Table 2 - Hydraulic Control Over Twenty Years
% control PCE % control TCE
Option I5
Option 26
Option 37
Option 48
66
72
74-
71
51
60
68
58
Based on this analysis, Option 3 would result in the greatest
reduction in mobility, particularly with respect to control of
the TCE plume. Options 2, 3, and 4 control to a similar degree
the PCE plume. Option 1 clearly results in a lesser degree of
56,000 gpm pumping rate, no reinjection
69,000 gpm pumping rate, no reinjection
712,000 gpm pumping rate, no reinjection
812,000 gpm pumping rate, with reinjection
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control. Option 3 turns out to be more efficient than Option 4,
despite the fact that these options use the same pumping rate of
12,000 gpm, because based on current projections nitrate levels
in the aquifer will not accommodate reinjection in hydraulically
advantageous locations. A hydraulically advantageous location
would be one where the reinjected water would assist in plume
containment. ARARs requirements would restrict the placement of
reinjection wells in areas where groundwater quality would not be
degraded, meaning in areas where nitrates in groundwater are
higher than nitrates in the water to be reinjected. If
reinjection wells could be placed in the most hydraulically
advantageous locations, Option 4 would be slightly superior to
Option 3 in this regard.
When the interim remedial action is complete, EPA projects that
contamination will remain in the groundwater under each of the
four options. The final remedial action will determine how to
address this remaining contamination.
Based on current data, Options 2 and 3 appear superior in terms
of this criterion, but all options fulfill the goal of the ROD to
partially control the movement and spread of groundwater
contaminants in the Burbank OU area, while contributing to
aquifer restoration.
6. Technical and administrative feasibility of implementation
The technical differences between the four options are as
follows:
Option 1 would require no additional construction. (Option
1 has already been implemented as Phase 1 of the interim
remedy; therefore, it has been proven feasible.)
Option 2 would require construction of 3,000 gpm of
additional extraction wellfield capacity.
Option 3 would require construction of 6,000 gpm of
additional extraction wellfield capacity, plus a 3,000 gpm
upgrade to treatment facility capacity.
Option 4 would require construction of 6,000 gpm of
additional extraction wellfield capacity, plus a 3,000 gpm
upgrade to treatment facility capacity, plus construction of
a 8,500 gpm reinjection wellfield.
In general, technical implementability increases in complexity as
construction tasks are added to a project. Some construction
tasks are more complex than others; for example, construction of
a reinjection wellfield is more complicated than construction of
an extraction wellfield due to more complex well specifications
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intended to reduce clogging of the well screens. Using this
rationale, Option 4 is more complex than Option 3, which is more
complex than Option 2, which is more complex than Option 1. As
stated above, Option 1 has already been implemented technically
(as well as administratively).
Ease of operation also factors into implementability.
Application of proven technology generally reduces uncertainty of
implementability, while application of a new technology increases
uncertainty. Options 1, 2, and 3 all use common technology,
while Option 4, by adding reinjection, uses a technology that has
not been implemented widely in the geographic region of the
Burbank OU.
Administratively, Options 1, 2, and 3, would be relatively simple
because they would follow the framework developed during start-up
of Phase 1 of the Burbank OU interim remedy. As part of Phase 1
start-up, EPA, the City of Burbank, Lockheed Martin Corporation,
and DHS reached agreement on operational plans for the facility.
Once again, Option 1, since it has been constructed and placed in
operation, is not expected to present any administrative
difficulties.
Construction of additional facilities, which would be necessary
under Options 2, 3, and 4, would require amending the City of
Burbank's public water supply operating permit, issued by DHS.
Although this would be an additional administrative task, EPA is
confident that additional permit conditions required by virtue of
the addition of such facilities, would be achievable.
Option 3 would have the administrative complication of committing
additional purveyors to accept water the City of Burbank could
not accept. It is not likely that these additional purveyors
would be willing to sign a consent decree, the chosen
implementation document for the interim remedy. Lockheed Martin
Corporation and the City of Burbank have both attempted, without
success as of the date of this ESD2, to obtain the commitment of
other local purveyors to accept Burbank OU water. Without this
commitment, there is a good deal of uncertainty whether 12,000
gpm of groundwater could be.purveyed on a routine basis, during
periods when the City of Burbank could not accept the entire
production of the Burbank OU facilities.
Option 4 would be more complicated to implement administratively
due to the likely increased involvement of a regulatory agency,
RVJQCB, in the process. RWQCB has previously expressed
reservations about reinjection based on water quality degradation
concerns. However, EPA believes this additional administrative
step would not present a barrier to implementation.
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Based on technical and administrative considerations, Options 1
and 2 are considered superior. Options 3 and 4 have
administrative complications, which would need to be resolved
prior to implementation. Option 3 may present a barrier to
implementation while Option 4 probably does not.
7. Capital and operation and maintenance costs
The following discussion compares the costs of Options 1-4 on a
net present value basis. Costs include construction and 20 years
of operation and maintenance. These costs are not based on the
original estimates set forth in the ROD and in ESDI, but are
based on more recent estimates prepared by a consultant to
Lockheed Martin Corporation, the entity which has undertaken
design and construction of the interim remedy under EPA
oversight. (See the Administrative Record: document entitled
Burbank Operable Unit Costs Comparison Summary, dated March 20,
1995, prepared by Parks, Palmer, Turner & Yemenidjian.) These
estimates were independently reviewed by CH2M Hill, EPA's ARCS
contractor. Therefore, the actual cost of the Phase 1 Burbank OU
treatment facilities constructed by Lockheed Martin, the City of
Burbank, and six other businesses, has been incorporated into
these estimates. CH2M Hill's analysis is presented in a
memorandum entitled Review of Burbank Operable Unit Costs
Comparison Summary, dated November 11, 1996. EPA has concluded
that the cost estimates prepared by Lockheed Martin used
appropriate assumptions and are therefore appropriate for
purposes of comparison of alternatives.
Option 1 is the least expensive of the four options. The capital
cost for this option is estimated at $31 million in 1996 dollars.
The present value of the 20 years of operation and maintenance is
estimated at $88 million. Therefore, the total net present value
of Option 1 is estimated at $119 million. Economic assumptions
used by Lockheed Martin's consultant in this analyses are as
follows: a discount rate of 8% was used; an inflation rate of 3%
was used; calculations are in 1995 dollars.
Option 2 is more expensive than Option 1 but less expensive than
Option 3. The capital cost for this option is estimated at $38
million in 1996 dollars. The present value of 20 years of
operation and maintenance is estimated at $93 million.
Therefore, the total net present value for Option 2 is estimated
at $131 million.
Option 3 is more expensive than option 2 but less expensive than
Option 4. The capital cost for this option is estimated at $49
million in 1996 dollars. The present value of 20 years of
operation and maintenance is estimated at $97 million.
Therefore, the total net present value for Option 3 is estimated
at $146 million.
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Option 4 is the most expensive of the four options. The capital
cost for this option is estimated at $70 million in 1996 dollars.
The present value of 20 years of operation and maintenance is
estimated at $110 million. Therefore, the total net present
value for Option 4 is estimated at $180 million.
For purposes of comparison, this information is set out in the
following table:
Table 3 - Cost Comparison
Ootion
I9
2io
3n
412
Capital
$31 million
$38 million
$49 million
$70 million
O&M
$ 88 million
$ 93 million
$ 97 million
$110 million
Total
$119 million
$131 million
$146 million
$180 million
8. State acceptance
EPA has coordinated with state agencies throughout this project,
specifically RWQCB, the California Department of Toxic Substances
Control (DTSC), and DHS. These agencies either accepted, or did
not object to, the interim remedy originally designated by the
ROD and ESDI. The Administrative Record details the
communications between EPA and these State agencies throughout
the interim remedy selection process.
•*
Regarding the remedy discussed in the ROD and ESDI, the record
reflects that the RWQCB supports the use of the treated water as
drinking water, provided that all requirements for the serving of
public drinking water are met. RWQCB agrees that reinjection may
be implemented as long as compliance is achieved with respect to
the "Statement of Policy With Respect to Maintaining High Quality
Waters in California." (See the Administrative Record: letter
dated June 8, 1990, from Hank Yacoub, RWQCB, to Alisa Greene,
EPA; letter dated June 20, 1990, from Robert Ghirelli, RWQCB, to
Alisa Greene, EPA.)
The record reflects that neither DTSC nor DHS stated a preference
or rejection of any of the options presented in the ROD and ESDI.
(See the Administrative Record: letter dated May 15, 1990, from
96,000 gpm pumping rate, no reinjection
109,000 gpm pumping rate, no reinjection
1112,000 gpm pumping rate, no reinjection
1212,000 gpm pumping rate, with reinjection
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Hamid Saebfar, DTSC, to Alisa Greene, EPA, and letter dated June
11, 1990, from Gary Yamamoto, DHS, to Alisa Greene, EPA.)
In addition to reviewing the Administrative Record through the
ROD and ESDI, EPA notified the state agencies regarding the
proposed changes which would be made by ESD2. Neither RWQCB nor
DTSC provided written comments on the options presented in ESD2.
However, as stated above, EPA also has presented EPA's position
on the ESD2 options to the state and other agencies at quarterly
Management Committee meetings. EPA's understanding based on
exchanges with representatives from these agencies is that
neither RWQCB nor DTSC objects to EPA's approach.
DHS did provide written comments on the changes proposed by ESD2,
but did not state a preference for any of the options presented
herein. (See the Administrative Record: letter dated September
6, 1996, from Gary Yamamoto, DHS, to David Seter, EPA.) DHS
raised the issue that "limiting the pumping rate to a maximum of
9,000 gpm and the elimination of the re-injection option may
limit U.S. EPA's future success in containing the contaminant
plume." In response to this comment, EPA believes the analysis
presented in this ESD2, in terms of the nine NCP criteria,
thoroughly considers the impact of the various options including
the impact on plume containment.
Specifically, the nitrate levels currently projected in the
aquifer do not accommodate reinjection in hydraulically
advantageous locations. The City t>f Burbank has already agreed
to maximize its use of treated groundwater, which will be an
average of 9,000 gpm. An extraction rate of 9,000 gpm without
reinjection thus accomplishes better hydraulic control than an
extraction rate of 12,000 gpm with reinjection.
9. Community acceptance
The basic groundwater extraction and treatment concepts being
evaluated in ESD2 do not differ greatly from the concepts
evaluated in the ROD and in ESDI. The same degree of treatment
will be applied to water made available as a public water supply.
During the thirty day comment period provided for by EPA during
the development of ESDI, there were no comments submitted by the
public.
In addition, EPA will publish notice of availability of this ESD2
in a local newspaper of general circulation, and will consider
any comments submitted by the public as required by 40 C.F.R.
Section 300.825 (c) .
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D. Decision on options
Based on the above analysis of Options 1-4, EPA has chosen Option
2, which consists of groundwater extraction at an average rate of
9,000 gpm, treatment by air stripping and granular activated
carbon to remove VOCs, nitrate reduction by blending with a low
nitrate water source, and use of the treated and blended water by
the City of Burbank as a public water supply.
Option 2 was chosen because:
1) it performs equally as well as Options 3 and 4 and
better than Option 1 at removing contaminant mass over
a 20 year period of time;
2) it performs substantially as well as Option 3 and
better than Options 1 and 4 at retarding migration of
the groundwater contamination plume;
3) its total implementation cost is
$15 million less than Option 3
$49 million less than Option 4 ,-
4) it avoids the potential administrative difficulties of
Options 3 (identifying additional water purveyors) and
4 (resolving reinjection regulatory issues);
5) it complies with ARARs;
6) it is protective of human health and the environment.
This is an interim remedy. In the future, after the Burbank OU
facilities have been operational for a substantial period of
time, the optimal extraction rate may be better determined. This
information will eventually factor into a decision on the final
remedy. But for the purposes of ESD2, the data suggest that a
groundwater extraction rate of 6,000 gpm may be too low to meet
the groundwater containment objective. However, the data do not
justify the added expense of raising pumping to a rate of 12,000
gpm. EPA has concluded that the Option 2 rate of 9., 000 gpm is a
reasonable, efficient, and cost-effective solution.
Although under ideal conditions pumping 12,000 gpm would provide
greater containment than pumping 9,000 gpm, the reality of the
ground water system as it exists in Burbank presents certain
limitations. Under ideal conditions, nitrate levels would be low
enough to meet ARARS reinjection requirements in areas determined
to be hydraulically advantageous to reinjection. This is not the
case, and is not likely to be the case throughout the time frame
for implementation of the interim remedy. Because reinjection
must take place in hydraulically disadvantageous locations, the
effectiveness of Option 4 is lessened.
The Option 2 pumping rate is 9,000 gpm, which represents a 25%
reduction in pumping versus Options 3 and 4. Yet, according to
analyses performed by Lockheed Martin with which EPA concurs,
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Option 2 is superior in containment to Option 4 and provides only
slightly less containment than Option 3.13 Furthermore, cost
savings for Option 2 are significant (a savings of 27% versus
Option 4).
Although additional cost savings are projected from further
reducing the pumping rate to 6,000 gpm (Option 1) , EPA believes
that, should water levels increase in the aquifer system, capture
could fall below acceptable levels under this option. As long as
9,000 gpm can be extracted and used without being wasted or
reinjected, EPA concludes that Option 2 presents the best balance
of reducing mobility of contaminants and cost-effectiveness.
As described above, EPA has also concluded that, for the purposes
of long-term containment, groundwater extraction need not equal
9,000 gallons per minute each day. This is why EPA has set a
goal of 9,000 gallons per minute as an annual average instead of
an instantaneous average. EPA also believes its approach of
allowing reduced groundwater extraction during periods of high
nitrate concentration increases protectiveness to public health
without adversely affecting long-term containment.
V. Support Agency Comments
The State of California agencies discussed in Section IV.C.8.
above are the support agencies for this action. Their comments
are addressed in that section. '
VI. Summary of Selected Remedy
The interim remedy for the Burbank Operable Unit, as selected in
the ROD and as modified by ESDI and ESD2, consists of groundwater
extraction at an average rate of 9,000 gpm, treatment by air
stripping and granular activated carbon to remove VOCs, nitrate
reduction by blending with a low nitrate water source, and use of
the treated and blended water by the City of Burbank as a public
water supply.
VII. Statutory Determinations
Considering the new information that has been developed, the EPA
believes that the interim remedy as modified by ESD2 remains
13This comparison was made based upon the degree of
hydraulic control exerted by the various options on the TCE/PCE
groundwater plume.
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protective of human health and the environment, complies with
federal and state requirements that are applicable or relevant
and appropriate to this interim remedial action, and is cost
effective. In addition, this remedy satisfies the statutory
preference for remedies that employ treatment which permanently
and significantly reduces the volume, toxicity or mobility of the
hazardous substances as a principal element. It also complies
with the statutory preference for remedies that utilize permanent
solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable. The
changes and clarifications contained in ESD2 are significant but
do not fundamentally change the remedy. They do not change the
decision to conduct an interim pump and treat action to inhibit
the spreading of the contaminated groundwater plume and to begin
aquifer restoration. They also do not alter the technologies
used in the interim remedy.
VIII. Public Participation Activities
EPA has presented these changes to the remedy in the form of an
Explanation of Significant Differences because the changes are of
a significant, but not fundamental, nature. The basic
groundwater extraction and treatment concepts being evaluated in
ESD2 do not differ greatly from the concepts evaluated in the ROD
and in ESDI. ESD2 and underlying information have been added to
the Burbank OU Administrative Record. Additional provisions for
public comment are not required foJ: an BSD (see 40 C.F.R. Section
300.435(c)(2)(i)), and EPA is not providing a formal public
comment period for ESD2. However, EPA has published notice of
the availability of ESD2 in a local newspaper as required by 40
C.F.R. Section 300.435(c) (2) (i) (B), and per 40 C.F.R. Section
300.825, will consider any significant comments submitted in a
timely manner.
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