PB95-964503
EPA/ROD/R09-95/133
June 1995
EPA Superfund
Record of Decision:
Newmark Groundwater Contamination
Muscoy Plume OU, San Bernardino, CA
3/24/1995
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MUSCOY PLUME OPERABLE UNIT
RECORD OF DECISION
PART I:
DECLARATION
PART II: DECISION SUMMARY
P ART III: RESPONSIVENESS SUMMARY
NEWMARK GROUNDWATER CONTAMINATION SUPERFUND SITE
SAN BERNARDINO, CALIFORNIA
United States Environmental Protection Agency
Region 9 - San Francisco, California
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TABLE ,OF CONTENTS
P82e No.
PART I. DECLARATION.............................................
PART n. DECISION SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Site Location and Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Site History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Enforcement Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Highlights of Community Participation. . . . . . . . . . . . . . . . . . . . . . . . . . . "
5. .Scope and Role of the Operable Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6. Summary of Muscoy Plume OU Site Characteristics. . . . . . . . . . . . . . . . . .
7. Summary of Site Risks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8. Description of Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9. Summary of Comparative Analysis of Alternatives. . . . . . . . . . . . . . . . . . .
10. Applicable or Relevant and Appropriate Requirements. . . . . . . . . . . . . . . .
11. The Selected Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12. Statutory Determinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13. Documentation of Significant Changes. . . . . . . . . . . . . . . . . . . . . . . . . . .
PART m. RESPONSIVENESS SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Written Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Comments from Public Meeting. . . . . . . . . . . . . . . . . . . . . . . . . .'. . . . . . .
LIST OF FIGURES
Figure 1. Location of Bunker Hill Groundwater Basin, San Bernardino, CA . . . . . . . . . .
Figure 2 Altitude of Potentiometric Surface and Direction of Groundwater Movement. .
Figure 3. Extent of Groundwater Contamination and Well Locations,
Newmark Superfund Site - Newmark and Muscoy Plumes. . . . . . . . . . . . . . . . . .
LIST OF TABLES
Table 1.
Table 2.
Maximum Concentrations of Volatile Organic Compounds. . . . . . . . . . . . .
Chemical -Specific Applicable or Relevant and Appropriate Requirements. .
1
4
4
9
10
11
12
14
14
17
19
22
31
33
33
34
34
35
5
6
8
13
25
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March 22. 1995
RECORD OF DECISION
MUSCOY PLUME OPERABLE UNIT INTERIM REMEDY
PART I. DECLARATION.
SITE NAME AND LOCATION
Newmark Groundwater Contamination Superfund Site
Muscoy Plume Operable Unit
San Bernardino, California
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the Muscoy Plume
Operable Unit, Newmark Groundwater Contamination Superfund site, chosen in accordance with
the Comprehensive Environmental Response, Compensation' and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986
(SARA), 42 ns.c. ~~9601 et seq., and, to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (National Contingency Plan or NCP), 40 CFR Part 300.
This decision is based on the administrative record for this operable unit.
In a letter to EPA dated March 21, 1995 the State of California, through the California
Environmental Protection Agency's (Cal-EPA) Department of Toxic Substances Control (DTSC)
concurred wiLlI the selected remedy for the Muscoy Plume Operable Unit.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare or the environment.
DESCRIPTION OF THE REMEDY
EP A has selected an interim remedy for the Muscoy plume of groundwater contamination
in the Newmark Groundwater Contamination Superfund Site. This portion of the site cleanup
is referred to as the Muscoy Plume Operable Unit (OU). An au is a discrete action that
comprises an incremental step toward comprehensively addressing Superfund site problems. The
Muscoy Plume au is an interim action focusing on contamination in the underground water
supply in the Bunker Hill Basin of San Bernardino, west of the Shandin Hills (Figures 1 and 2).
The portion of the groundwater contamination north and east of the Shandin Hills, called the
Newmark OU, was addressed in a separate action (Newmark OU Record of Decision, August 4,
1993). The selected remedy and all of the alternatives presented in the feasibility study were
developed to meet the following specific objectives for the Muscoy Plume OU:
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.
To inhibit migration of groundwater contamination into clean portions of the aquifer;
.
To protect downgradient municipal supply wells south and southwest of the Shan din Hills;
.
To begin to remove contaminants from the groundwater plume for eventual restoration
of the aquifer to beneficial uses. (This is a long-term project objective rather than an
immediate objective of the interim action.)
The remedy involves groundwater extraction (pumping) and treatment of 6.200 gallons
per minute (gpm) in San Bernardino at the leading edge of the contaminant plume (Fig. 2). which
is approximately between Highland Avenue and Base Line Street. west of Interstate 215 and east
of Medical Center Drive. The exact number. location and other design specifics of the extraction
wells will be determined during the remedial design phase of the project to inhibit the migration
of the contaminant plume most effectively. . .
All the extracted contaminated groundwater shall be treated to remove Volatile Organic
Compounds (VOCs) by either of two proven treatment technologies: granular activated carbon
(GAC) filtration or air stripping. EPA determined during the Feasibility Study (December
1994) that these treatment technologies are equally effective at removing VOCs and are similar
in cost at this Ou. Both technologies have been proven to be reliable in similar applications.
The VOC treatment technology which best meets the objectives of the remedy for the Muscoy
Plume OU will be determined during the remedial design phase. when more detailed information
is available to assess effectiveness and cost.
After treatment. the water shall meet all applicable or relevant and appropriate drinking
water standards for VOCs (See Table 2). If air stripping treatment is selected. air emissions shall
be treated using the best available control technology (e.g.. vapor phase GAC) to ensure that all
air emissions meet applicable or relevant and appropriate requirements.
The treated water will be transferred to a public water supply agency for distribution.
Groundwater monitoring wells will be installed and sampled regularly to help evaluate the
effectiveness of the remedy.
If the public water supply agency does not accept any or all of the treated water (possibly
due to water supply needs), any remaining portion of water will be recharged into the aquifer via
reinjection wells near the edge of the plume. The number, location and design of the reinjection
wells will be determined during the remedial design phase to best meet the objectives of the
remedy and meet applicable or relevant and appropriate requirements.
The total duration of the Muscoy Plume OU interim remedy will be approximately 33
years, with the first three years for design and construction. EP A will review this action every
five years throughout this interim remedy period and again at .the conclusion of this period to
ensure that the remedy continues to be protective of human health and the environment.
The remedial action for the Muscoy Plume OU represents a discrete element in the overall
long-term remediation of groundwater at the Newmark Groundwater Contamination Superfund
Site. The objectives of this interim action (i.e., inhibiting migration of groundwater contamination
to clean portions of the aquifer, protecting downgradient municipal supply wells south and
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Muscov Plume Record of Decision
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March 22. 1995
southwest of the Shandin Hills and peginning to remove contaminant mass from the aquifer in
the Muscoy plume) are not inconsistent with and will not preclude implementation of any final,
overall remedial action or actions selected by EP A in the future for the Newmark Groundwater
Contamination Superfund Site.
EPA is the lead agency for this project and the Department of Toxic Substances Control
of the State of California Environmental Protection Agency is the support agency.
DECLARATION
This interim action is protective of human health and the environment, complies with
federal and state applicable or relevant and appropriate requirements directly associated with this
action and is cost effective. This action utilizes permanent solutions and alternative treatment
(or resource recovery) technologies to the maximum extent practicable, given the limited scope
of the action. Because this action does not constitute the final remedy for the site, the statutory
preference for remedies that employ treatment that reduces toxicity, mobility, or volume as a
principal element will be addressed at the time of the final response action. Subsequent actions
are planned to fully address the principal threats at this site.
Because this interim remedy will result in hazardous substances remaining on-site above
health-based levels, EPA shall conduct a review, pursuant to CERCLA Section 121, 42 U.S.C.
Section 9621, at least once every five years after commencement of remedial action to ensure that
the interim remedy continues to provide adequate protection of human heaith and the
environment.
~H
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PART II. DECISION SUMMARY
This Decision Summary provides an overview of the Muscoy Plume OU interim remedy,
including a description of the nature and extent of contamination to be addressed, the remedial
alternatives, the comparative analysis of the remedial alternatives, a description of the selected
remedy and the rationale for remedy selection.
1. SITE LOCATION AND DESCRIPTION
The Muscoy Plume OU is located within the Bunker Hill Basin (also known as the Upper
Santa Ana River Basin) in San Bernardino, California. The following sections present a basin
description, regulatory history, and a summary of the Remedial Investigation and Feasibility
Study (RIfFS) activities within the Newmark Groundwater Contamination Superfund Site
(hereinafter referred to as the Newmark Superfund Site). .
1.1. Description of the Bunker Hill Basin
The groundwater contamination at the Newmark Superfund Site affects a large portion of
a 110 square mile aquifer in the San Bernardino Valley of southern California. (Figure 1). The
aquifer, known as the Bunker Hill Basin, is bounded by the San Bernardino and San Gabriel
Mountains to the north, the Crafton Hills and badlands on the southeast, and by a hydrogeologic
barrier formed by the San Jacinto fault along the southwest. (Figure 2) Waters flowing from all
parts of the aquifer join in a confined "artesian zone" before leaving the basin where the Santa
Ana River crosses the San Jacinto faultline.
The groundwater in this aquifer is a valuable resource, currently serving nearly a half-
million residents of San Bernardino, Riverside and surrounding communities. According to the
San Bernardino Valley Municipal Water District, the Bunker Hill Basin aquifer is capable of
storing approximately 1.6 trillion gallons and producing 81 billion gallons each year.
. Coarse erosional material (alluvial and river channel deposits) have accumulated in the
this area of the basin to depths of 400 to over 1900 feet, atop bedrock formations that act as
barriers to further vertical movement. The Shandin Hills, created by an upward fold. in these
impermeable bedrock formations, forces groundwater flowing from the north and west to flow
around either side of the hills rather than directly south toward the Santa Ana River. .
Most of the western portion of the basin is an unconfined aquifer, with no substantial
barriers to infiltration from the surface. In the lowest area of the basin (the south-central portion
around the Santa Ana River), several extensive clay layers have formed an aquitard, overlying
and capping the water-bearing sand and gravel aquifers. This confined portion of the aquifer
produces a large supply of water for nearby communities. The aquifer receives rainfall and
natural. runoff from the surrounding mountains, collected floodwater from rivers, creeks and
washes, and water imported from outside the region that is spread over percolation basins.
The Muscoy plume encompasses a portion of the Bunker Hill aquifer located beneath the
western portion of the city of San Bernardino and an unincorporated part of San Bernardino
County known as the Muscoy community. Residential and commercial use predominates
throughout the Newmark Superfund Site. Very little of the area remains undeveloped.
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FIGURE 2.
Altitude of Groundwater Surface and Direction of Groundwater Flow (1986)
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Muscoy Plume Record of Decision
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March 22. 1995
1.2 Description and Background of the Newmark Superfund Site
The primary contaminants of concern at the Newmark Superfund Site are the solvents
perchloroethylene (PCE) and trichloroethylene (TCE), which are widely used in a variety of
industries, including dry cleaning, metal plating, and machinery degreasing. These organic
solvents are in a class of chemicals, known as volatile organic compounds (VOCs), which
evaporate (volatilize) readily at room temperature. If large enough amounts ofPCE and TCE are
spilled or leaked onto the ground, these chemicals can reach the aquifer where they will slowly
dissolve into groundwater. As the contaminated water flows away from the source, a plume of
contaminated water can spread many miles downstream. Wells within the plume will be pumping
contaminated water. .
As of 1995, PCE and TCE in concentrations exceeding the drinking water standards of
5 micrograms per liter (parts per billion) have been detected in 20 public water supply wells in
northern San Bernardino. The pattern of contamination, defined by sampling monitoring wells
and water supply wells throughout the Newmark Superfund Site (see Figure 3), indicates that a
release or releases occurred in northwest San Bernardino (approximately in the area of a former
military depot known as the San Bernardino Engineering Depot or camp Ono), and that
contaminants have spread more than five miles toward the Santa Ana river to the southeast. A
major outcrop of relatively impermeable bedrock (the Shandin Hills) splits the plume of
contaminated groundwater into an eastern branch (the Newmark plume) and a western branch (the
Muscoy plume). EPA is addressing the leading edges of the plume as two separate Operable
Units. The identification, characterization and remediation of the source of contamination will
constitute a third Operable Unit. The Rl/FS report for the Newmark OU was finalized in March,
1993, and EP A's Regional Administrator signed a Record of Decision for the Newmark OU
interim remedy on August 4, 1993. The Newmark OU Remedial Design was initiated in
September, 1993, and is expected to be completed in early 1995. .
1.3 Description and Background of the Muscoy Plume Operable Unit
The Muscoy Plume OU encompasses a portion of the Bunker Hill Basin aquifer beneath
the northern portion of the city of San Bernardino and an unincorporated portion of San
Bernardino County known as the Muscoy community. The Muscoy plume is the western lobe
of the Newmark Superfund Site groundwater contamination. This contamination has migrated
south of Highland Avenue in San Bernardino along a flow path roughly parallel to the"Cajon
Wash. The Cajon Wash, a major recharge zone of the Bunker Hill groundwater basin, prevents
the contaminants from migrating further west and tends to push the contaminants toward the east.
The Shandin Hills bedrock outcrop limits the eastern flow of the Muscoy plume. The leading
edge of the Muscoy plume arrived at San Bernardino's 19th Street wells in the mid to late 1980's
but has not yet reached the wells at 10th Street, approximately one mile to the southeast. At an
estimated flow rate of 300 to 500 feet per year, contaminated groundwater would require ten to
twenty years to migrate from the 19th Street wells to the 10th Street wellfields.
The EPA placed the Newmark site on the National Priorities List (NPL) in March, 1989.
At that time, EP A believed the eastern (Newmark) plume of contamination to be completely
separate from the western (Muscoy) plume of groundwater contamination.
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Muscov Plume Record of Decision
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March 22. 1995
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FIGURE 3. Extent of Groundwater Contamination and Well Locations,
Newmark Superfund Site - Newmark and Muscoy Plumes
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Muscov Plume Record of Decision
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March 22. 1995
The EP A Remedial Investigation (RI) began in late 1990, focusing entirely on the
Newmark plume. Results from the RI showed that the originally suspected source of the
Newmark plume (a disposal pit for waste liquids from a former airport) was not the source of
the contamination. Additional well drilling in the summer of 1992 traced the groundwater
contamination back through a previously undiscovered underground channel flowing from the
western (Muscoy) side of the valley. EPA expanded the Newmark Superfund Site Remedial
Investigation in September, 1992 to include the Muscoy plume.
Due to EP A's experience with the Newmark plume and to the availability of over ten
years of water quality data from state and local groundwater investigations in San Bernardino,
EP A was able to expedite the Remedial Investigation of the Muscoy Plume QU. In 1992 all
available wells in the vicinity of the Muscoy plume were sampled by EP A. PCE and TCE were
the most prevalent contaminants in all of the contaminated wells. Other VQCs were also
detected in trace quantities. These results were consistent with water quality samples analyzed
by state and local authorities since 1980.
In 1993, EPA recognized that sufficient information had been collected to develop interim
action alternatives to control the spread of the Muscoy plume while proceeding with field work
to identify the source. The Muscoy Plume OU has the limited objectives of addressing migration
at the leading edge of the plume while EPA continues to investigate the source of the
contamination. The RIfFS Report for the Muscoy Plume OU was finalized in December, 1994.
2. SITE mSTORY
In 1980, the California Department of Health Services (DHS) initiated a monitoring
program in San Bernardino to test for the presence of industrial chemicals in the water from
public supply wells. The results of initial tests and of subsequent testing revealed the presence
of PCE and TCE contamination in large portions of the groundwater of the Bunker Hill Basin.
Fourteen wells operated by the city of San Bernardino Water Department in the North San
Bernardino / Muscoy area were found to contain concentrations of PCE and TCE above the state
and federal MCLs of 5 parts per billion (ppb) for both TCE and PCE. The solvents were found
in wells scattered around the north, east and west sides of the Shandin Hills. (Figure 3) The
affected wells had supplied nearly 25 percent of the water for the city of San Bernardino. As
of 1995, a total of thirteen public water supply wells have been contaminated by the solvents in
the Newmark plume, and seven water supply wells have been affected in the Muscoy plume.
The cities of San Bernardino, Riverside and other water agencies in the area closely
monitor the quality of drinking water delivered to residents. These entities have taken the
necessary steps to ensure that the water served to residents meets all federal and state drinking
water requirements.
Following investigations by the Santa Ana Regional Water Quality Control Board and .
California Department of Health Services (now. the California EP A Department of Toxic
Substances Control), the state provided over $6 million to construct four water treatment systems
to protect the public water supply. After years of testing it became apparent that the solvents in
the groundwater were continuing to flow south, threatening many more wells operated by San
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Muscov Plume Record of Decision
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March 22. 1995
Bernardino, Riverside and other communities. The state requested federal involvement to address
this regional problem.
The state investigations published in 1986 and 1989 both suggested that the widespread
contamination in northern San Bernardino probably resulted from numerous small, unidentified
sources. The Shandin Hills and nearby hill formations were assumed to separate the eastern
(Newmark area) aquifer from the western (Muscoy area) aquifer. making it unlikely that all 14
wells could have been contaminated from a single source. However. continued monitoring of
existing water supply welis and monitoring wells constructed by the state established a record
of contamination relatively uniform in composition and concentration throughout the area north
and east of the Shandin Hills. This pattern strongly suggested a single plume in this area.
Aerial photographic analysis of the Newmark Superfund Site was completed by EP A's
Environmental Monitoring Systems Laboratory in September, 1990. This analysis, along with
interviews of witnesses, suggested that the primary source of contamination was a suspected
solvent disposal pit ("cat pit") on the former site of the private San Bernardino Airport. Waste
oil and solvents were disposed of at this site from the late 1950's intermittently through the early.
1970's. Several minor. activities in different parts of the airport site were also identified as
potential waste releases. No other sources could be identified between the disposal site and the
closest uncontaminated wells upgradient. The waste disposal pit was also within several hundred
feet of the Newmark wellfield (four City of San Bernardino Water Department wells). These
wells exhibited the highest concentration of contaminants measured in any wells in the area,
nearly 200 ~gll (parts per billion) of PCE.
Based on information obtained during the Remedial Investigation, the San Bernardino
Airport site is no longer suspected to be the source of the Newmark plume. It is now believed
that the principle source (or sources) lies on the west side of the Shandin Hills and is the likely
origin of both the Newmark and Muscoy plumes.
While ongoing investigations attempt to definitively identify the source, EP A determined
that the continuing migration of the Muscoy plume could be inhibited through an interim
remedial action (the Muscoy Plume aU).
3. ENFORCEMENT ACTIVITIES
The results of the Remedial Investigation and other investigations undertaken by EP A and
state agencies indicate that the project lead for the Muscoy Plume au will remain with EP A.
As explained above, the disposal pits at the fonner San Bernardino Airport site were
originally suspected to be the source of the contamination. Considerable effort was expended on
a search for Potentially Responsible Parties (PRPs) while the airport site disposal pits were the
suspected source. However, results of the Remedial Investigation reveal that the source of the
contamination is more than one mile upgradient of the originally suspected source. No residual
contamination was found in the unsaturated zone or the upper portion of the aquifer immediately
beneath former disposal pits. The airport site is no longer considered a likely source of the
contamination.
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March 22. 1995
The current focus of the PRP search is on the potential sources located to the northwest
of the Shandin Hills. These potential sources include the San Bernardino Engineering Depot (a
WWTI-era army base decommissioned in 1947, commonly known as Camp Ono), a closed county
landfill (the Cajon landfill), and subsequent industrial activities at the site of the former Camp
Ono.
EPA formally requested detailed information from the Department of Defense (DoD)
concerning the operations at the former Camp Ono in 1993 and again in 1994. A partial reply
to the earlier request was received November, 1993. In this response, the DoD noted that
solvents h!id been used and disposed of at the base. The designated DoD representative reported
that research into EP A 's 1994 information request has commenced. The Department of Defense
was notified of itS potential liability in a General Notice letter sent on December 22, 1993. EP A
and DoD (through the Army Corps of Engineers) have been communicating regularly regarding
the Newmark Superfund Site throughout 1994. On December 16, 1994, the designated
representative of the Department of Defense was sent a copy of the Muscoy Plume Proposed
Plan, with a transmittal letter stating that the Muscoy Plume OU was the second OU of the
Newmark Superfund Site. EPA noted that the previous General Notice letter sent on December
22, 1993, notified DoD of potential liability for the entire Newmark Superfund Site.
4. IDGHLIGHTS OF COMMUNITY PARTICIPATION
EPA's preferred remedial alternative, as well as four other alternatives were described in
EP A's Proposed Plan for the Muscoy Plume au (December 1994). The Proposed Plan was in
the form of a fact sheet and was distributed to all parties (approximately 700) on EP A's mailing
list for the Newmark project. The public comment period was extended to more than 5 weeks
(38 days) to compensate for the holiday period in December. EPA received no requests for
extensions from members of the public. The public comment period closed on january 20, 1995.
EP A received approximately 16 comments, with a large proportion relating to source
characterization rather than control of the Muscoy plume. These comments and EP A's responses
to these comments are summarized in Part ill (the Responsiveness Summary) of this ROD.
A press release to announce the release of the Proposed Plan was issued December 16,
1994. The press release and the Proposed Plan Fact Sheet announced that a public meeting to
discuss and receive comments on the Muscoy Plume Proposed Plan was scheduled for January
10, 1995. Notice of the public meeting as well as the availability of the Proposed Plan was
published in the Inland Empire Sun on December 14, 1994. In addition, several newspaper
articles were written about the Remedial Investigation, the Feasibility Study and the Proposed
Plan for the Muscoy Plume OU. A map of the Muscoy Plume OU was provided in the Proposed
Plan and the above-referenced newspaper articles published maps and described the area that
would be impacted by the Muscoy Plume OU.
A public meeting was held in the City of San Bernardino Council Chambers on January
10, 1995, to discuss EP A's preferred alternative and the other alternatives. At this meeting EP A
gave a brief presentation regarding the Proposed Plan, answered questions, and accepted
comments from members of the public. This meeting was broadcast live on the local cable
channel.
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Muscov Plume Record of Decision
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March 22. 1995
EPA expended considerable effort developing strong community relations. A Technical
Advisory Committee has been successful in maintaining close communication with local and state
agencies. For communication with the local community, three principle mechanisms have been
employed: formal presentations (open houses, meetings with organizations and fact sheet
distribution), contact with the print and electronic media, and informal discussions with home-
owners' associations and individuals.
Three different home-owners' associations, the Muscoy Municipal Advisory CoUncil and
several water supply agencies accepted EPA's offer for informal discus~ions of the project.
Drilling around these communities was greatly facilitated by open communication, including
distribution of four fact sheets. Presentations were made to the staff and teachers at a local
school, and the Project Manager taught the 5th grade class about groundwater and chemical
pollution as it relates to the project.
5.
SCOPE AND ROLE OF THE OPERABLE UNIT
The interim remedial action for the Muscoy Plume OU represents a discrete element in
the overall long-term remediation of groundwater contamination in the San Bernardino area.
Since the source of the contamination has not been definitively identified, the final overall plan
for the remediation of the entire Newmark Groundwater Contamination Site has not yet been
determined. The Muscoy plume constitutes a major portion of the contaminated aquifer and the
Muscoy Plume OU interim remedial action will be a significant step toward eventual remediation.
EP A does not expect the objectives of this interim action to be inconsistent with, or preclude, any
final action for the entire site.
The objectives of the Muscoy Plume au are:
.
To inhibit migration of groundwater contamination into clean portions of the aquifer;
.
To protect downgradient municipal supply wells south and southwest of the Shandin Hills;
.
To begin to remove contaminants from the groundwater plume for eventual restoration
of the aquifer to beneficial uses. (This is a long-term project objective rather than an
immediate objective of the interim action.) .
The analysis of the No Action option indicates that unless this action is implemented, the
contamination will continue to spread to clean areas of the aquifer which are currently important
sources of drinking water.
When sufficient information is available on the contaminant source and transport from the
source, EPA will review and evaluate various groundwater remediation options for the entire
Newmark Superfund Site. It is expected that the Muscoy Plume au remedy will constitute an
integral part of the final remedy.
EP A will continue to monitor aquifer behavior and contaminant transport as part of this
interim action. The information gathered will be important in the analysis of a remedy for the
entire Newmark Superfund Site. .
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Table 1. Maximum Concentrations of Volatile Organic Compounds Detected
(above 0.5 J.lg/l detection limit) in Wells in the Muscoy Plume
Compound Maximum
Concentration
(Jlg/l)
1,1 Dichloroethane (DCA) 0.8
cis-l,2-Dichloroethene (DCE) 6
Trichloroethene (TCE) 6
Tetrachloroethene (PCE) 27
Dichlorodifluoromethane 28
(Freon 12)
Trichlorofluoromethane 4
(Freon 11)
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6. SUMMARY OF MUSCOY PLUME OU SITE CHARACTERISTICS
EPA's Remedial Investigation provided critical understanding in three general areas:
groundwater flow characteristics, contaminant identification and concentration, and potential
routes of exposure.
The Remedial Investigation confirmed that most recharge to the Muscoy Plume au part
of the Bunker Hill Basin originates along the San Bernardino and San Gabriel Mountains to the
north via the Cajon Wash along the west. Drinking water wells north and west of the site show
that this source is not contaminated. Another important observation was that clay or silt layers
that would inhibit vertical contaminant migration were not present in wells near the leading edge
of the plume. This indicates that contaminants at any depth in the aquifer would not be
prevented from entering water supply. wells in the area, regardless of the depth of the water
supply well. A groundwater flow model was successfully developed to describe the aquifer
behavior and proved to be a useful tool in developing remedial alternatives.
The contaminants identified were predominantly chlorinated solvents. (Table 1)
Tetrachloroethene (PCE) wasfound in all contaminated wells at concentrations less than 30 parts
per billion (ppb). Trichloroethene (TCE) was the next most common contaminant, and never
exceeded 10 ppb. Other related contaminants of concern, cis-l,2-dichloroethene (DCE) and 1,1-
dichloroethane (DCA), were identified at concentrations below drinking water standards.
Chlorofluorocarbons (freons) were also detected.
Analysis of potential exposure routes during the Remedial Investigation concluded that
the only measurable exposure to the VOCs would be through untreated domestic water supply.
Several state and EP A investigations failed to identify VOC contamination at the surface or
within ten feet of the soil surface anywhere at the Newmark Superfund Site. Consequently, direct
contact with VOC's via surface soil is not a possible exposure route. Further EP A investigations
examined the potential for volatile chemicals to enter residences through the soil. Direct in-
. home measurements confirmed EP A calculations that this also is not a possible exposure route.
Exposure through untreated domestic water supply is discussed thoroughly in the Site Risk
section below.
7.
SUMMARY OF SITE RISKS
Baseline risk assessments are conducted at Superfund sites to fulfill one of the
requirements of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP).
The NCP (40 CFR Part 300) requires development of a baseline risk assessment at sites listed
on the National Priorities List (NPL) under CERCLA. The CERCLA process for baseline risk
assessments is intended to address both human health and the environment. However, due to the
nature of the contamination at the site and the highly urbanized setting of the Muscoy Plume OU,
the focus of the baseline risk assessment was on human health issues rather than environmental
Issues.
The objective of the baseline risk assessment for the Muscoy Plume au was to evaluate
the human health and environmental risks posed by the contaminated groundwater if it were to
be used as a source of drinking water without treatment. The baseline risk assessment
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incorporated the water quality information generated during the RI field investigation and
sampling program to estimate current and future human health and environmental risks.
The risk assessment was conducted in accordance with BPA guidance including:
Guidance for Conducting Remedial Investigation and Feasibilitv Studies under CERCLA
(USEPA. 1988), Risk Assessment Guidance for Superfund. Vol. I Health Evaluation Manual (rart
A) and Vol. 2 Ecological Assessment (USEPA, 1989). The Exposure Factors Handbook (USEPA,
1989), and Risk Assessment Guidance for SUDerfund Human Health Risk Assessment. USEPA
Region IX Recommendations (USEP A, 1989).
. A risk assessment involves the qualitative and quantitative characterization of potential
health effects of specific chemicals on individuals or populations. The risk assessment process
comprises four basic steps: 1) hazard identification. 2) dose-response assessment, 3) exposure
assessment, and 4) risk characterization. The purpose of each element is as follows:
Hazard identification characterizes the potential threat to human health and the
environment posed by the detected constituents.
Dose response assessment critically examines the toxicological data used to
determine the relationship between the experimentally administered animal dose
and the predicted response (e.g., cancer incidence) in a receptor.
Exposure assessment estimates the magnitude, frequency, and duration of human
exposures to chemicals.
Risk characterization estimates the incidence of or potential for an adverse health
or environmental effect under the conditions of exposure defined in the exposure
assessment.
Human Health Risk Assessment
The potential for non-carcinogenic health effects was estimated by calculating a hazard
index for the sum of all the compounds of potential concern in the Muscoy plume. The health
index compares the levels of contaminants in the groundwater with levels that could cause an
adverse non-cancer health effect. If the total hazard index reaches 1.0 or above, there may be
a concern for potential health risks. The hazard index for the Muscoy Plume OU was less than
0.5, which indicated that non-carcinogenic health effects are negligible.
The risk assessment also estimated the possibility that additional occurrences of cancer
will result from exposure to contamination. The background probability of developing cancer
from all causes in California is approximately one in four (or 250,000 in a million). An excess
cancer risk of 1 in a million means that a person exposed to a certain level of contamination
would increase the risk of developing cancer from 250.000 in a million to 250,001 in a million
as a result of the exposure. EP A considers excess cancer risks greater than 100 in a million to
be unacceptable.
In preparing risk assessments, EP A uses very conservative assumptions that weigh in favor
of protecting public health. For example. EP A may assume that individuals consume two liters
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of drinking water from wells situated within a contaminant plume every day for a 30-year period,
even though typical exposure to the chemical would be far less.
EPA included two potential exposure routes (ways the contamination gets into the body)
in the risk assessment:
.
drinking the groundwater during residential use; and
.
inhaling the chemicals in groundwater as vapors during showering.
Skin contact with contaminated water was also considered but EPA found that it did not
pose a significant risk. Results of the RI indicated that direct exposure to volatile organic
compounds (VOCs) from surface soil or from water 100 feet below ground was insignificant at
this site (see Section 6.0 - Summary of Site Characteristics).
Chemicals of potential concern in the Muscoy Plume OU used in the risk assessment
calculations included: PCE. TCE. cis-l.2-Dichloroethene (DCE). and other VOCs detected in at
least one well. EP A will continue to monitor the groundwater in the Muscoy Plume OU for any
changes that would affect the risk analysis.
The results of the risk assessment indicated that the current contaminant levels in the
aquifer of the Muscoy Plume OU would not meet state or federal drinking water standards if this
water were to be delivered directly to local residents. without being treated. However. the levels
are currently below the concentrations that would pose an unacceptable risk to human health. as
defined by CERCLA. If the groundwater were used as a drinking water source without
treatment. the chance of developing cancer during a lifetime would increase by as much as 50
in a million. EPA is taking an action at the Muscoy Plume OU in order to meet the drinking
water standards (MCLs) even though the risk levels do not exceed 100 in a million.
The baseline risk assessment for the Muscoy Plume OU is presented in the Remedial
Investieation and Feasibility Study Report for the Muscov Plume OU (December 1994).
Environmental Risk Assessment
Given the present developed condition of the site and the major exposure pathway
consideration of contaminated groundwater. there was no expectation for significant impact to
potential environmental receptors. Urbanization has already replaced habitat potential; therefore.
no significant number of receptors appeared to be present. There appeared to be no apparent
mechanism for exposure to environmental receptors from contaminated groundwater. Also. there
was no indication that future site plans would reinstate habitat and thereby recreate ~ potential
for environmental receptors in the future.
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8. DESCRIPTION OF ALTERNATIVES
Development of Alternatives to Meet Proiect Obiectives
Before developing a range of cleanup alternatives for evaluation, EP A identified the
objectives of the interim cleanup for the Muscoy Plume OU. All of the alternatives were
screened for: 1) effectiveness at protecting human health and the environment, 2) technical
feasibility (implementability), and 3) cost. In addition, the alternatives were developed to meet
the specific cleanup objectives for the Muscoy Plume OU described previously.
Based on the results of the RI, EPA identified five cleanup alternatives for addressing
groundwater contamination of the Muscoy Plume Ou. Detailed descriptions of these alternatives
are provided in the Muscoy Plume OU RIlFS Report (December, 1994). Rather than including
all potential combinations of extraction locations and amounts, the initial screening process
identified the most efficient extraction scenario that would meet our objectives. The five
alternatives were evaluated based on nine specific criteria: 1) Overall Protection of Human
Health and the Environment, 2) Compliance with Applicable or Relevant. and Appropriate
Requirements (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, and 9) Community Acceptance.
With the exception of the Alternative 1 - No Action, all of the alternatives involve the
extraction of an estimated 6,200 gallons per minute (gpm) of groundwater near the leading edge
of the plume for a period of 3 ° years. The actual design capacity of the extraction and treatment
facilities will be determined during the Remedial Design phase based on the latest refined
groundwater information and modeling. The RIlFS Report analysis indicated that the final
extraction rate is expected to be within the range of 5,000 gpm to 7,000 gpm. Individual wells
would pump from 800 to 2,000 gpm, the range for. a typical city drinking water well.
A computer model was used to determine that these extraction rates would result in
effective inhibition of plume migration and optimal contamination removal for this interim action.
With the exception of Alternative 1 - No Action, all of the alternatives would involve the
construction and operation of a VOC treatment system, construction and sampling of additional
monitoring wells, and analysis of any changes in the current operations of nearby public water
supply wells.
During the first three years after issuance of the ROD, the remedy would proceed to the
remedial design and initial implementation stages. EP A must plan, build the equipment and test
it to make sure it functions properly.
ALTERNATIVE 1: No Action
This alternative serves as a baseline to compare other alternatives. This alternative is
evaluated to determine the risks that would be posed to public health and the environment if no
action were taken to treat or contain the contamination. The No Action Alternative would
involve only groundwater monitoring; no additional cleanup activities would be conducted. The
cost of constructing the necessary monitoring wells and sampling them over 30 years would be
approximately $2.2 million (present net worth).
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ALTERNATIVE 2: ExtractITreat(Granular Activated Carbon)/Public Water Agency
Extraction
Alternative 2 involves the extraction of an estimated 6,200 gpm of contaminated
groundwater placed at the leading edge of the Muscoy plume. The actual design capacity of the
extraction and treatment facilities will be determined during the Remedial Design phase based
on the latest refined groundwater information and modeling. The extraction wells would be
located to inhibit most effectively the migration of the contaminant plume.
Treatment
The extracted groundwater would be transmitted via underground piping to a Granular
Activated Carbon (GAC) treatment plant EPA assumed that an entirely new treatment plant
would be constructed near the extraction system and near a major distribution system pipeline.
It may be possible to use an existing treatment plant site with construction of pipeline to the plant
and from the plant to the distribution pipeline. Note that Alternative 3, involving treatment by
air stripping, is considered by EP A to be equivalent to Alternative 2, and may be substituted for
all or part of Alternative 2 during the design phase of the project.
Transfer of Treated Water
The treated water would meet all applicable or relevant and appropriate drinking water
standards for VOCs and would be piped to a public water supply agency for distribution.
Groundwater monitoring wells would be installed to evaluate the effectiveness of the remedial
action. Following approximately 2 to 3 years for design and construction, this system would
operate for 30 years. Operation of nearby public water supply wells are not expected to interfere
with this remedy, although any significant changes in operations would be analyzed to determine
the effect on this cleanup action. EPA will conduct a formal assessment of the project
effectiveness every five years.
The present net worth cost of Alternative 2. including capital costs and thirty years of operation
and maintenance, is estimated at $26,000,000.
ALTERNATIVE 3:
Agency
Extractffreat(Air Stripping with Emission Control)/Publk Water
Alternative 3 involves the same extraction system, transfer of treated water to a public
water agency and monitoring design as Alternative 2. Alternative 3 differs from Alternative 2
in the treatment of the extracted groundwater to remove VOCs to meet applicable or relevant and
appropriate drinking water standards for VOCs. In Alternative 3, the extracted contaminated
water would be treated by air stripping with emission control to meet the South Coast Air Quality
Management District's requirement for best available control technology. Currently, vapor-phase
granular activated carbon meets this requirement, and EP A used this technology for cost and
effectiveness analysis. New emissions control technologies developed prior to the final design
could be considered if they meet the air quality requirement. Air stripping is essentially equal
to GAC (Alternative 2) in effectiveness, technical feasibility and the remaining criteria.
The present net worth cost of Alternative 3, including capital costs and thirty years of operation
and maintenance, is estimated at $21,500,000.
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ALTERNATIVE 4: Extractlfreat (Advanced Oxidation - Peroxide/Ozone)/ Public Water
Agency
Alternative 4 involves the same extraction, transfer of treated water to a public water
agency and monitoring design as Alternative 2. The extracted water would be treated for VOCs
using an advanced oxidation process that uses peroxide and ozone to destroy (oxidize) the
contaminants (rather than transferring the contaminants to a carbon filter). The treated water
would meet all applicable or relevant and appropriate drinking water standards for VOCs and
would be piped to a public water supply agency. Groundwater monitoring wells would be
installed to evaluate the effectiveness of the action.
The present net worth cost of Alternative 4. including capital costs and thirty years of operation
and maintenance. is estimated at $32,000.000. .
ALTERNATIVE 5: Extractlfreat (GAC or Air Stripping)/Return to the Aquifer via
Reinjection.
Alternative 5 involves the same extraction, treatment and monitoring' designs as
. Alternative 2 (including the option to use either GAC or air stripping to treat the extracted water
for VOCs). The water would be returned to the aquifer in reinjection wells downgradient from
the extraction wells. The treated water would meet state reinjection standards before being
returned to the aquifer.
The present net worth cost of Alternative 5. including capital costs and thirty years of operation
and mainteriance, is estimated at $30,800,00.0.
9.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
A comparative analysis of the alternatives against the nine evaluation criteria set forth in
the NCP at 40 CFR 300.430 (e)(9)(iii) is presented in this section.
No Action versus the Nine Criteria. Clearly, Alternative 1 would not be effective in the short-
and long-term in protecting human health and the environment as it does not provide for
removing any contaminants from the aquifer. for inhibiting further downgradient contaminant
plume migration, or for reducing the toxicity, mobility and volume of contaminants through
treatment. Implementing the no-action alternative would be simple and inexpensive since it
involves only groundwater monitoring. As indicated by the baseline risk assessment presented
in the RI Report, Alternative 1 could pose carcinogenic risk if a person were exposed to the
untreated groundwater through the domestic water supply, although the risk is below the 100 in
a million excess risk level (10.4) which EP A considers generally unacceptable. The current
contaminant level would not meet state or federal drinking water standards if this water were to
be delivered directly to local residents without treatment. Loss of a valuable water resource from
continued degradation of the aquifer is a major concern for the state and the public.
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Overall Protection of Human Health and the Environment, Short Term Effectiveness and
Long Term Effectiveness. Alternatives 2, 3, 4 and S have the same effectiveness in the short
and long term in reducing the risk to human health and the environment by removing
contaminants from the aquifer, by inhibiting further downgradient contaminant migration, and by
reducing the toxicity, mobility and volume of contaminants in the aquifer.
i
!
, .
Reduction of Toxicity, Mobility and Volume through Treatment. The VOC treatment.
technologies used in Alternatives 2, 3 andS (either air stripping with emission control (e.g.,
vapor-phase GAC adsorption) or liquid phase GAC adsorption) are technically feasible and
effective in meeting ARARs for VOCs in the extracted and treated groundwater. Treatment of
the extracted contaminated groundwater via air stripping with vapor-phase GAC .adsorption or
via liquid phase GAC adsorption would reduce substantially the toxicity and mobility. of
contaminants in the aqueous phase. The adsorption of contaminants onto the GAC would reduce
the volume of contaminated media. However, a substantially larger quantity of contaminated
GAC media would be generated with either air stripping with vapor-phase GAC or liquid-phase
GAC systems compared to perozone oxidation (which is a destructive technology) followed by
either air stripping with vapor-phase GAC adsorption or liquid-phase GAC. This contaminated
GAC would require disposal or regeneration. During the design phase, an alternative emission
control technology will be tested to eliminate the need for vapor-phase GAC while meeting the
Best Available Control Technology requirement.
Treatment of the extracted contaminated groundwater via perozone oxidation in
Alternative 4 would destroy greater than 90. percent of the VOCs, and generate a smaller quantity
. of contaminated GAC media compared to the conventional technologies alone. VOC treatment
using perozone oxidation has only been tested and applied in pilot-scalellimited applications, and
limited O&M data are available. Concern has been expressed over the day-to-day reliability of
this innovative technology at large-scale application for drinking water supply treatment.
Incomplete oxidation can lead to the formation of by-products such as formaldehyde which would
also need to addressed. The reliability concerns for large-scale applications, coupled with the
uncertainties associated with design, capital and operational costs and with the fact that a public
water supply agency will be receiving the treated water, all combine to make Alternative 4 less
preferable than Alternatives 2, 3 and 5 which propose using liquid phase GAC or air stripping
for VOC treatment.
Compliance with ARARs. As discussed in the ARARs section (Section 10) of this ROD, since
this remedial action is an interim action, there are no chemical-specific ARARs for aquifer
cleanup for any of the alternatives. For Alternatives 2 through 4, the chemical-specific ARARs
for the treated water from the VOC treatment plant at this site are the federal and state -drinking
water standards for VOCs set forth in Table 2. Alternative S must meet the standards set forth
in Table 2 as well as state reinjection standards. Alternatives 2, 3, and 5 are expected to meet
these ARARs for the treated water. There is some uncertainty regarding the ability of Alternative
4 to meet these ARARs because perozone has not been used to treat such high concentrations
of VOCs at such high flow rates. Therefore, there is the potential for not meeting chemical-
specific ARARs unless the air stripping or liquid-phase GAC unit following the perozone system
is a redundant treatment system (which would add substantially to the cost).
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Implementability. Technically and administratively. Alternatives 2. 3. and 5 could be
implemented. although the cooperation of a public water supply agency would be required for
implementation of Alternatives 2 and 3. The technologies considered for groundwater
monitoring. extraction. and conveyance are proven and have been applied extensively. For
Alternative 5. the availability of an appropriate on-site location for reinjection of extracted and
treated groundwater would need to be addressed. .
State and Public Acceptance. Based on comments received during the public comment period,
the public generally expressed support for Alternatives 2 through 5, although reservations were
expressed about alternatives 3. 4 and 5. EPA received comments from water agencies in the
area specifically in support of the end use aspects of alternatives 2 and 3. Comments received
during the public comment period along with EP A responses are presented in Part ill of this
ROD, the Responsiveness Summary. In a letter dated March 21. 1995, the State of California
(Cal-EPA) concurred with EPA's selected remedy for the Muscoy Plume OU.
Cost. The estimated total present worth of Alternatives 2, 3 and 5 ranges from $21.500,000 to
$30.800.000. The total present worth cost for Alternative 4 is $32,000,000. For alternatives 2,
3 and 4, some of these costs are expected to be offset by the water supply agencies which accept
the treated water. These overall project costs do not take into account the value of utilizing the
groundwater resource directly as opposed to recharging the water to the aquifer to be eventually
pumped to the surface again prior to use (Alternative 5).
The GAC treatment system already operating at the San Bernardino Municipal Water
Department's facility at 19th Street and California Avenue may be incorporated into this action
and would provide significant cost savings. Construction of pipeline to a distribution system
capable of accepting the full volume of treated water would be required.
Selected Remedy.
EPA's comparative analysis of the remedial alternatives against the nine evaluation criteria
concluded that Alternative 2 (extraction. treatment by GAC and transfer to public water supply
agency) most fully meets the nine criteria. Accordingly. EPA has selected Alternative 2 as the
interim remedial action for the Muscoy Plume Ou. Alternative 3, involving treatment by air
stripping, is considered by EP A to be equivalent to Alternative 2, and may be substituted for all
or part of Alternative 2 during the design phase of the project. In addition. EP A recognizes the
need for cooperation from a public water supply agency to implement alternatives 2 or 3.
Consequently, EPA selects Alternative 5 (extraction. treatment and reinjection into the aquifer)
as a contingency if water supply agencies are unable to accept all of the treated water. Section
11 of the ROD provides a detailed discussion of the major components of the selected remedy.
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10.
APPLICABLE OR RELEVANT AND APPROPRIATE REOUIREMENTS
This section discusses Applicable or Relevant and Appropriate Requirements (ARARs)
for the selected remedy for the Muscoy Plume OU. Section 121(d) of CERCLA requires that
remedial actions attain a level or standard of control of hazardous substances which complies
with ARARs of federal environmental laws and more stringent state environmental and facility
siting laws. Only state requirements that are more stringent than federal ARARs, and are legally
enforceable and consistently enforced may be ARARs. .
An ARAR may be either "applicable", or "relevant and appropriate", but not both. The
National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300,
defines "applicable" and. "relevant and appropriate" as follows:
ADDlicable requirements are those cleanup standards, standards of control, or other
substantive environmental protection requirements, criteria, or limitations
promulgated under federal or state environmental or facility siting laws that
specifically address a hazardous substance, pollutant, contaminant, remedial action,
location, or other circumstance found at a CERCLA site. Only those state
standards that are identified by a state in a timely manner and that are more
stringent than federal requirements may be applicable. "Applicability" implies that
the remedial action or the circumstances at the site satisfy all of the jurisdictional
prerequisites of a requirement. .
Relevant and appropriate requirements are those cleanup standards, standards of
control, and other substantive environmental protection requirements, criteria, or
limitations promulgated under federal environmental or .state environmental or
facility siting laws that, while not "applicable" to a hazardous substance, pollutant,
contaminant, remedial action. location, or other circumstance at a CERCLA site,
address problems or situations sufficiently similar to those encountered at the
CERCLA site that their use is well suited to the particular site. Only those state
standards that are identified in a timely manner and that are more stringent than
federal requirements may be relevant and appropriate.
On-site CERCLA actions must comply with the substantive requirements of all ARARs.
Off-site activities must comply with both substantive and administrative requirements of all .
applicable laws. Substantive requirements are requirements that apply directly to actions or
conditions in the environment. Examples include quantitative health or risk-based standards for
contaminants. Administrative requirements are those mechanisms that assist in the implementation
of the substantive requirements (such as reporting, record keeping, and permit issuance), but do
not in and of themselves define a level or standard of control. (See 55 Fed. Reg. 8756).
ARARs fall into three broad categories, based on the manner in which they are applied
at a site. These categories are as follows:
Chemical-Specific ARARs. Chemical-specific ARARs are health- or risk-based concentration
limits, numerical values, or methodologies for various environmental media (i.e., groundwater,
surface water, air, and soil) that are established for a specific chemical that may be present in a
specific media at the site, or that may be discharged to the site during remedial activities. These
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ARARs set limits on concentrations of specific hazardous substances, pollutants, and
contaminants in the environment. Drinking water maximum contaminant levels (MCLs) are
examples of chemical-specific ARARs.
Location-Specific ARARs. Location-specific ARARs are federal and state restrictions placed
on the concentration of a contaminant or on activities to be conducted because they are in a
specific location. Examples of restricted locations include flood plains, wetlands, historic places,
and sensitive ecosystems or habitats.
Action-Specific ARARs. Action-specific ARARs are technology- or activity-based requirements
which determine how a remedial action must be performed. Examples are Resource, Conservation
and Recovery Act (RCRA) regulations for hazardous waste treatment, storage or disposal.
Neither CERCLA nor the NCP provides across-the-board standards for determining
whether a particular remedy will result in an adequate cleanup at a particular site. Rather, the
process recognizes that each site will have unique characteristics that must be evaluated and
compared to those requirements that apply under the given circumstances. Therefore, ARARs
are identified on a site-specific basis from information about specific chemicals at the site,
specific features of the site location, and actions that are being considered as remedies.
The following section outlines the ARARs that apply to the interim remedial action at this
site:
10.1 Chemical-Specific ARARs
The chemical-specific ARARs for the contaminants of concern at the Muscoy Plume au
are set forth in Table 2 and discussed in the following sections.
10.1.1 Federal Drinking Water Standards
Safe Drinking Water Act (SDW At 42 U.S.C. S300f et seq.. National Primary Drinking Water
Regulations. 40 CFR Part 141.
Federal MCLs and MCLGs.
EP A has promulgated Maximum Contaminant Levels (MCLs) under the Safe Drinking
Water Act (SDW A) to protect public health from contaminants that may be found in drinking
water sources. Although these requirements are only applicable at the tap for water provided
directly to 25 or more people or which will be supplied to 15 or more service connections, they
are relevant and appropriate to water that is a current or potential source of drinking water.
Because the treatment plant effluent from the Muscoy Plume au is a potential source of drinking
water, EP A has determined that the federal MCLs for the vacs and any more stringent State of
California MCLs for these vacs are relevant and appropriate to the treatment plant effluent. In
accordance with NCP section 300.430(e)(2)(i)(B), EPA has also concluded that non-zero
Maximum Contaminant Level Goals (MCLGs) are also relevant and appropriate to treatment
plant effluent from the Muscoy Plume au which may be served as drinking water.
The Muscoy Plume au is an interim remedial action designed primarily to inhibit the
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spread of contamination. Consequently, chemical-specific requirements for the ultimate cleanup
of the aquifer. which would be ARARs for a final remedy, are not ARARs for this interim action.
(See 55 Fed. Reg. 8755.)
Under Alternatives 2 and 3, EP A will transfer the treated groundwater to a public water
supply agency. EPA considers the subsequent serving of the water by the public supply agency
(at the tap) to be an off-site, post-remedy activity. Consequently, if the treated water is served
as drinking water, all legal requirements for drinking water in existence at the time the water is
served will have to be met. Since these requirements are not ARARs, they are not "frozen" as
of the date of the ROD. Rather, they can change over time as laws and regulations applicable to
drinking water change.
10.1.2 State Drinking Water Standards
California Safe Drinking Water Act. Health and SafetY Code. &4010 et seq.. California Code of
Regulations. Title 22. Division 4. Chapter 15. &64401 et seq.
California Maximum Contaminant Levels (MCLs): 22 CCR 64444.5
The State of California has established drinking water standards for sources of public
drinking water, under the California Safe Drinking Water Act, Health and Safety Code Sections
4010 et seq. California MCLs for VOCs are set forth at 22 CCR 64444.5. Several of the state
MCLs are more stringent than federal MCLs. In these cases, EP A has determined that the more
stringent state MCLs for VOCs are relevant and appropriate for the treatment plant effluent from
the Muscoy Plume OU interim remedy. The VOCs for which there are more stringent state
standards include cis-I,2-dichloroethene (DCE). There are also some chemicals where state
MCLs exist but there are no federal MCLs. EP A has determined that these state MCLs are
relevant and appropriate for the treated water prior to discharge or delivery to the water purveyor.
The VOCs for which there are no federal MCLs but for which state MCLs exist include 1,1-
dichloroethane (DCA).
California Secondary Drinking Water Standards (SDWS): 22 CCR 64471
The State of California has also promulgated Secondary Drinking Water Standards
(SDWS) applicable to public water system suppliers, which address the aesthetic characteristics
of drinking water. See 22 CCR ~64471. Although California SDWS are not applicable to non-
public water system suppliers, the California SDWS are relevant and appropriate to the Muscoy
Plume OU interim action if the treated water is transferred to a public water supply agency for
distribution. It should be noted that federal SDWS have not been identified as ARARs for this
action because they are not enforceable limits and are intended as guidelines only. In summary,
if the treated water is to be served as drinking water, the treated water at the point of delivery
must meet the California SDWS for the contaminants of concern at the Muscoy Plume Ou. If
the treated water is recharged or (temporarily) discharged to surface waters, the water will not
be required to meet State SDWS.
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Table 2. Chemical -Specific Applicable or Relevant and Appropriate Requirements at the
Muscoy Plume Operable Unit for Treated Water Transferred to Public Water Supply Agency
Compound ARAR ARAR
(pgll) (Regulation)
1,1 Dichloroethane (DCA) 5 California MCL
cis-l,2-Dichloroethene (DCE) 6 California MCL
Trichloroethene (TCE) 5 Federal MCL
Tetrachloroethene (PCE) 5 Federal MCL
Dichlorodifluoromethane -- --
(Freon 12)
Trichlorofluoromethane 150 California MCL
(Freon 11)
Notes:
MCL = Maximum Contaminant Level
"--" indicates that no non-zero MCL, MCLG or SDWS has been promulgated
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10.2 Locatiort-SDecific ARARs
No special characteristics exist in the Muscoy Plume OU to warrant location-specific
requirements. Therefore, EP A has determined that there are no location-specific ARARs for the
Muscoy Plume OU.
10.3
Action-Specific ARARs
The action-specific ARARs for the Muscoy Plume OU interim remedy are as follows:
10.3.1 Air Oualitv Standards
Clean Air Act. 42 US.C. &7401 et seq.: California Health & Safety Code &39000 et seq.
South Coast Air Quality Management District Rules 401, 402, 403, 1301-13, 1401
The Muscoy Plume OU alternative treatment of VOCs by air. stripping, whereby the
volatile chemical compounds are emitted to the atmosphere, triggers action- specific ARARs with
respect to air quality.
The Clean Air Act, 42 US.C. ~7401 et seq., and California Health & Safety Code ~39000
et seq., regulate air emissions to protect human health and the environment, and are the enabling
statutes for air quality programs and standards. The substantive state and federal ambient air
quality standards are implemented primarily through Air Pollution Control Districts. The South
Coast Air Quality Management District (SCAQMD) is the district regulating air quality in the
San Bernardino area.
The SCAQMD has adopted rules that limit air. emissions of identified toxics and
contaminants. The SCAQMD Regulation XIV, consisting of Rule 1401, on new source review
of carcinogenic air contaminants is applicable for the Muscoy Plume OU SCAQMD Rule 1401
requires that best available control technology (T -BACT) be employed for new stationary
operating equipment, so the cumulative carcinogenic impact from air toxics does not exceed the
maximum individual cancer risk limit of ten in one million (1 x 10-5). EP A has determined that
this T-BACT rule is applicable for the Muscoy Plume OU because carcinogenic compounds such
as PCE and TCE are present in groundwater, and release of these compounds to the atmosphere
may pose health risks exceeding SCAQMD requirements. The substantive portions of SCAQMD
Regulation XIll, comprising Rules 1301 through 1313, on new source review are also applicable
to the Muscoy Plume OU. .
The SCAQMD also has rules limiting the visible emissions from a point source (Rule
401), prohibiting discharge of material that is odorous or causes injury, nuisance OT annoyance
to the public (Rule 402), and limiting down-wind particulate concentrations (Rule 403). EPA has
determined that these rules are also applicable to the Muscoy Plume OU interim remedy.
10.3.2 Water Ouality Standards for Reiniection to the Aquifer
If any treated water is reinjected to the aquifer, the treated water must meet all state and
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March 22. 1995
. federal action-specific ARARs for such reinjection.
(Alternative 5) are as follows:
The ARARs applicable to reinjection
Federal Reiniection Standards
Federal Underground Injection Control Regulations: 40 CFR 144.12 - 144.13
The Safe Drinking Water Act. 42 .U.S.C. ~300f et seq., provides federal authority over
injection wells. The Federal Underground Injection Control Plan, codified at 40 C.F.R Part 144,
prohibits injection wells such as those that would be located at the Muscoy Plume OU from (1)
causing a violation of primary MCLs in the receiving waters and (2) adversely affecting the
health of persons. 40 C.F.R ~144.12. Section 144.13 of the Federal Underground Injection
Control Plan provides that contaminated ground water that has been treated may be reinjected
into the formation from which it is withdrawn if such injection is conducted pursuant to a
CERCLA cleanup and is approved by EPA. 40 C.F.R. ~144.13. These regulations are applicable
to any Muscoy Plume au treated water that is reinjected into the aquifer.
Resource Conservation and Recovery Act ~3020, 42 V.S.C. ~6939b
Section 3020 of the Resource Conservation and Recovery Act (RCRA) is also applicable
to the Muscoy Plume au interim action. This section of RCRA provides that the ban on the
disposal of hazardous waste into a formation which contains an underground source of drinking
water (set forth in Section 3020(ať shall not apply to the injection of contaminated groundwater
into the aquifer if: (i) such injection is part of a response action under CERCLA; (ii) such
contaminated groundwater is treated to substantially reduce hazardous constituents prior to such
injection; and (iii) such response action will, upon completion, be sufficient to protect human
health and the environment. RCRA Section 3020(b).
. ~
State Reiniection Standards
State Water Resources Control Board Resolution 68-16.
State Water Resources Control Board Resolution No. 68-16, which is incorporated in the
Santa Ana Regional Water Quality Control Board's Water Quality Control Plan for the Santa Ana
River (and specific Bunker Hill sub-basins), is applicable to the Muscoy Plume OU interim action
to the extent that treated water is reinjected into the aquifer. Resolution 68-16 requires
maintenance of existing state water quality unless it is demonstrated that a change will benefit
the people of California, will not unreasonably affect present or potential uses, and will not result
in water quality less than that prescribed by other state policies.
The EP A Region IX Regional Administrator's decision in the matters of George Air Force
Base and Mather Air Force Base (July 9, 1993) sets forth a balancing process to be used on a
case-by-case basis to determine reinjection standards for treated groundwater under Resolution
68-16. This process requires that the following three factors be balanced in order to determine
the permitted discharge level: (1) site-specific considerations, including the hydrogeologic
conditions at the site, the contaminants discharged, the quality of the receiving water and the
designated beneficial uses of the receiving water; (2) treatment technologies; and (3) cost.
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March 22. 1995
. Based upon the balancing process set forth in this decision and on a site-specific analysis
of the Muscoy Plume OU, EPA has concluded that the substantive reinjection standard for PCE,
DCE, TCE, and DCA at the Muscoy Plume OU will be 0.5 ppb on a monthly median basis for
each compound. This conclusion is based on data gathered over the last several years at existing
state-funded groundwater treatment plants operating at the leading edge of the contaminant
plumes of the Newmark Superfund Site. This site-specific information shows that contaminant
levels in the groundwater remain within a range that has been consistently treated to below 0.5
ppb TCE/PCE/DCE/DCA using conventional treatment technologies (Granular Activated Carbon
and Air-Stripping). The cost, operating and water quality data from these existing treatment plants
leads EPA to believe that the 0.5 ppb level can be effectively and economically attained on a
monthly median basis assuming essentially identical conditions in the Muscoy Plume remedial
action. EPA's analysis relies on data from the existing treatment plants and assumes that EPA
will be reinjecting the treated water into relatively clean groundwater at or near the edge of the
contaminant plume.
Based on data from existing treatment plants as well as industry-wide treatability studies,
EP A has concluded that neither freon 11 nor freon 12 can be treated effectively and economically
by liquid-phase or vapor-phase granular activated carbon. More importantly, EPA's Risk
Assessment for this Operable Unit shows no increased risk to human health and the environment
from freon at this site. EP A has concluded that the reinjection standards for freon 11 is the MCL
for freon 11 (150 ppb). It should be noted that the maximum concentration of freon 11 and freon
12 detected in the Muscoy Plume investigation area was 4 ppb for freon 11 and 28 ppb for freon
12.
10.3.3 Water Oualitv Standards for Temporary Discharges to Surface Water
National Pollutant Discharge Elimination System Program (NPDES)
EP A anticipates that there may be incidental, short-term discharges of groundwater to the
San Bernardino County flood control channel or to the City of San Bernardino storm drains
during certain remedial activities (for example, during construction of the groundwater extraction
system, the VOC treatment plant, and the monitoring wells, during groundwater sampling, and
during system maintenance). The ARAR for any groundwater that is discharged, on a short-term
basis, to surface waters is the National Pollutant Discharge Elimination System (NPDES) Program
which is implemented by the Sarita Ana Regional Water Quality Control Board (SARWQCB).
Based on the waste discharge limitations adopted by the SARWQCB in Order No. 91-63-043,
EP A has determined that groundwater that will be discharged, on a short-term basis, to surface
waters on-site must meet state or federal MCLs (whichever is more stringent) for PCE, TCE,
DCE, and DCA.
10.3.4
Hazardous Waste Management
California Hazardous Waste Control Act. Health & Safety Code. Division 20. Chapter 6.5
The State of California has been authorized to enforce its own hazardous waste regulations
(California Hazardous Waste Control Act) in lieu of the federal RCRA program administered by
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March 22. 1995
the EP A. Therefore, state hazardous waste regulations in the California Code of Regulations
(CCR), Title 22, Division 4.5 are now cited as ARARs instead of the federal RCRA regulations.
Under 22 CCR Section 66261.31, certain "spent" halogenated solvents, including TCE and
PCE, are listed hazardous wastes. (RCRA waste code F002). Although TCE, PCE and certain
other halogenated solvents are the contaminants of concern in the groundwater at the Muscoy
Plume OU, the source of these contaminants has not yet been determined, and the contaminants
. cannot therefore be definitively classified as listed RCRA hazardous wastes. However, the
contaminants are sufficiently similar to listed RCRA hazardous wastes that EP A has determined
that portions of the state hazardous waste regulations are relevant and appropriate to the Muscoy
Plume OU interim action.
VOC Treatment Plant Requirements: 22 CCR ~~ 66264.14, 66264.18, 66264.25,
66264.600-.603, and 66264.111-.115
The substantive r~quirements of the following general hazardous waste facility standards
are relevant and appropriate to the VOC treatment plant: 22 CCR Section 66264.14 (security
requirements), 22 CCR Section 66264.18 (location standards) and 22 CCR Section 66264.25
(precipitation standards).
In addition, an air stripper or GAC contactor would qualify as a RCRA miscellaneous unit
if the contaminated water constituted RCRA hazardous waste. EP A has determined that the
substantive requirements for miscellaneous units set forth in Sections 66264.600 -.603 and related
substantive closure requirements set forth in 66264.111-.115 are relevant and appropriate for the
air stripper or GAC contactor. The miscellaneous unit and related closure requirements are
relevant and appropriate because the water is similar to RCRA hazardous waste and the air
stripper or GAC contactor appear to qualify as miscellaneous units. Consequently, the air stripper
or GAC contactor should be designed, operated, maintained and closed in a manner that wili
ensure the protection of human health or the environment.
. ..
Certain other portions of the state's hazardous waste regulations are considered to be
relevant but not appropriate to the VOC treatment plant. EPA has determined that the substantive
requirements of Section 66264.15 (general inspection requirements), Section 66264.15 (personnel
training) and Sections 66264.30-66264.56 (preparedness and Prevention and Contingency Plan
and Emergency Procedures) are relevant but not appropriate requirements for this treatment
system. EP A has made this determination because the treatment plant will be required to have
health and safety plans and operation and maintenance plans under CERCLA that are
substantively equivalent to the requirements of Sections 66264.15, 66264.30-66264.56.
Land Disposal Restrictions: 22 CCR ~66268
The land disposal restrictions (LDR) set forth in 22 CCR Section 66268 are relevant and
appropriate to on-site disposal of contaminated groundwater on land. The remedial alternatives
presented do not include on-site land disposal of untreated groundwater, except as may occur
through activities incidental to the remedial activity, such as purging monitoring wells. Any
water discharged to land must meet state or federal MCLs, whichever is more stringent, prior to
discharge. Such water would not constitute a RCRA hazardous waste and would therefore not
trigger LDRs.
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The LDRs set forth in 22 CCR 66268 are also relevant and appropriate to the on-site
disposal of spent carbon on land. These restrictions would be applicable if the spent carbon
contains suffiCient quantities of hazardous constituents to render it a characteristic hazardous
waste. However, the remedial alternatives presented do not contemplate on-site disposal of spent
carbon on land and are therefore unlikely to trigger LDRs.
Storage Requirements: 22 CCR ~~66262.34, 66264.170 - 66264.178
The container storage requirements in 22 CCR Sections 66264.170 -.178 are relevant and
appropriate for the on-site storage of contaminated groundwater or spent carbon over 90 days.
The substantive requirements of 22 CCR Section 66262.34 are relevant and appropriate for the
on-site storage of contaminated groundwater or spent carbon for less than 90 days. These
requirements would be applicable if the contaminated groundwater or the spent carbon contained
sufficient quantities of hazardous constituents to render them characteristic hazardous wastes.
10.4 Other Performance Standards
The NCP authorizes EP A and the state to identify advisories, criteria, guidance or
proposed standards to-be-considered (rnCs) that may be helpful or useful in developing
CERCLA remedies. NCP, 40 CFR Sections 300AOO(g)(3) and 300.430(b)(9). Such TBCs are
identified in the RIfFS and may be selected by EP A as requirements for the remedial action in
the ROD.
EP A has determined that certain substantive standards for the construction of public water
supply wells published by the State of California (the California Water Well Standards) and
identified as TBCs in the RIfFS should be requirements for the Muscoy OU interim remedy.
While these standards have not been specifically promulgated as an enforceable regulation and
are therefore not ARARs, all groundwater facilities designed, located and constructed to produce
drinking water must be constructed in accordance with these standards. Since the Muscoy Plume
OU interim remedy involves transfer of the treated water to the public water supply agency, EP A
has determined that the remedial action will comply with substantive Water Well Standards for
construction of water supply wells, such as sealing the upper annular space to prevent surface
contaminants from entering the water supply. Standards for location of the extraction wells are
not appropriate, since the effectiveness of the remedial action is dependent upon the well
locations. Additionally, wells constructed solely for treatment and reinjection with no delivery
to the public supply water system will not be subject to these water well construction standards.
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March 22. 1995
11. THE SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the detailed analysis of the
alternatives, and public comments, EP A has determined that Alternative 2: extraction, treatment
of VQCs by liquid phase GAC (or air stripping with best available control technology for
emissions), and conveyance to a public water supply agency, is the most appropriate interim
remedy for the Muscoy Plume QU. If the public water supply agency does not accept any or all
of the treated water, then Alternative 5: extraction, treatment of VQCs, and recharge to the
aquifer, will be implemented.
Alternative 2 involves groundwater extraction (pumping) of approximately 6,200 gallons
per minute (gpm) near the leading edge of the plume for a period of 30 years. The actual design
capacity of the extraction and treatment facilities will be determined during the Remedial Design
phase based on refined groundwater information and modeling. The RIlFS Report analysis
indicated that the final extraction rate is expected to be within the range of 5,000 gpm to 7,000
gpm. Individual wells would pump from 800 to 2,000 gpm, the range for a typical city drinking
water well. During the remedial design phase the locations proposed for extraction wells and
scenarios for rates of extraction per individual well may be selected or new ones may be selected.
The exact number, location and other design specifics of new extraction wells will be determined
during the remedial design phase of the project to inhibit the migration of the contaminant plume
most effectively.
All the extracted contaminated groundwater shall be treated to remove vacs by either
of two proven treatment technologies: granular activated carbon (GAC) filtration or air
stripping. EPA determined during the Feasibility Study (December 1994) that these treatment
technologies are equally effective at removing VQCs and are similar in cost at this au. Both
technologies have been proven to be reliable in similar applications. Existing treatment facilities
(e.g., the GAC treatment system at the 19th Street wellfield) may be modified and incorporated
into the remedy as appropriate. The VQC treatment technology which best meets the objectives
of the remedy for the Muscoy Plume QU will be determined during the remedial design phase,
when more detailed information is available to assess effectiveness and cost.
The treated water exiting the treatment plant shall meet all applicable or relevant and
appropriate MCLs, non-zero MCLGs and secondary drinking water standards. If air stripping
treatment is selected, air emissions shall be treated using the best available control technology
(e.g., vapor phase GAC or an acceptable innovative technology) to ensure that all air emissions
meet ARARs.
The treated water will be piped to the public water supply agency for distribution.
Construction of pipeline to a distribution system capable of accepting the full volume of treated
water would be required. It may be possible to use an existing treatment plant site with
construction of pipeline to the plant and from the plant to the distribution pipeline.
Groundwater monitoring wells will be installed and sampled regularly to help evaluate the
effectiveness of the remedy. More specifically, groundwater monitoring will be conducted no
less frequently than quarterly to obtain information needed to: 1) evaluate influent and effluent
water quality, 2) determine and evaluate the capture zone of the extraction wells, 3) evaluate the
vertical and lateral (including downgradient) migration of contaminants, 4) (if the contingency
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March 22. J 995
alternative is implemented) to evaluate the effectiveness of the recharge well system and its
impact on the remedy and 5) to monitor any other factors associated with the effectiveness of the
interim remedy determined to be necessary during remedial design. Monitoring frequency may
be decreased to less than quarterly if EP A determines that conditions warrant such a decrease.
EP A has selected Alternative 5 as a contingency if the public water supply agency does
not accept any or all of the treated water (possibly due to water supply needs). Any remaining
portion of water will be recharged into the aquifer via reinjection wells near the edge of the
plume. The number, location and design of the reinjection wells will be determined during the
remedial design phase to best meet the objectives of the remedy and meet applicable or relevant
. and appropriate requirements. With the exception of the need to meet state reinjection standards
and final use of the treated water, the. extraction, treatment and monitoring components of
Alternative 5 are identical to Alternative 2 above.
The total duration of the Muscoy Plume OU interim remedy will be approximately 33
years, with the first three years for design and construction. EP A will review this action every
five years throughout this interim remedy period and again at the conclusion of this period.
The VOC treatment plant of the Muscoy Plume OU interim remedy (whether it be
Alternative 2, Alternative 5 or a combination thereof) shall be designed and operated so as to
prevent the unknowing entry, and minimize the possible effect of unauthorized entry, of persons
or livestock into the active portion of the facility. A perimeter fence shall be erected around the
VOC treatment plant if an adequate fence or other existing security system is not already in place
at the plant site. This fence should be in place prior to initiation of the remedial action and
should remain in place throughout the duration of the remedy. The VOC treatment plant shall
also be designed and operated so as to prevent releases of contaminated groundwater from the
plant.
The selected remedy for the Muscoy Plume OU meets all of EP A's nine evaluation
criteria. The selected remedy is equally effective as the other alternatives in the short-term and
long term reduction of risk to human health and the environment by removing contaminants from
the aquifer, by inhibiting further downgradient migration of the contaminant plume, and by
reducing the toxicity, mobility and volume of contaminants in the aquifer.
The VOC treatment technologies selected (liquid phase GAC or air stripping with best
available control technology for emissions) are technically feasible and proven effective at
meeting ARARs for VOCs in the treated groundwater.
Alternative 2, in combination with Alternative 5, could be implemented, both technically
and administratively.
In a letter dated March 21, 1995, the State of California concurred with EPA's selected
remedy. EPA received several public comments during the public comment period, the majority
of which generally expressed support for Alternatives 2 through 5, although reservations were
expressed about alternatives 3, 4 and 5. EPA received comments from water agencies in the
area specifically in support of the end use aspects of alternatives 2 and 3. These comments,
along with EP A's responses are presented in Part III of this ROD, the Responsiveness Summary.
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March 22. 1995
The selected remedy is protective of human health and the environment, meets ARARs,
and provides beneficial uses (distribution to a public water supply agency and/or recharge) for
the treated water. The selected remedy is cost-effective. The estimated cost of Alternative 2 has
a total present worth of $26,000,000, which is in the middle of the range for all five alternatives.
The estimated total cost of Alternative 5 is $30,800,000.
12. STATUTORY DETERMINATIONS
As required under Section 121 of CERCLA, the selected interim remedial action is
protective of human health and the environment, complies with Federal and State requirements
that are legally applicable or relevant and appropriate to the interim remedial action, and is cost
effective. The selected remedy utilizes permanent solutions and alternative treatment technologies
to the maximum extent practicable and satisfies the statutory preference for remedies that employ
treatment to reduce toxicity, mobility, and volume as a principal element.
The selected interim remedial. action is protective of human health and the environment
in that it removes significant VOC contaminant mass from the upper zones of the aquifer and
inhibiting further downgradient and vertical migration of contaminated groundwater.
The VOC treatment technologies selected (liquid phase GAC or air stripping with best
available control technology for emissions) are technically feasible and proven effective at
meeting ARARs for VOCs in the treated groundwater and the air.
The selected remedy permanently and significantly reduces the toxicity, mobility and
volume of hazardous substances in the aquifer as well as the extracted groundwater.
Because this remedy will result in hazardous substances remaining on-site above health-
based levels, EPA shall conduct a review, pursuant to CERCLA Section 121,42 U.S.C. Section
9621, at least once every five years after commencement of remedial action to ensure that the
remedy continues to provide adequate protection of human health and the environment.
13. DOCUMENTATION OF SIGNIFICANT CHANGES
No significant changes to EP A's preferred alternative resulted from comments received
during the public comment period.
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March 22. 1995
PART III. RESPONSIVENESS SUMMARY
For PUBLIC COMMENTS RECEIVED from
DECEMBER 14. 1994. through JANUARY 20, 1995
ON THE PROPOSED PLAN FOR THE
MUSCOY PLUME OPERABLE UNIT INTERIM REMEDIAL ACTION
AT THE NEWMARK GROUNDWATER CONTAMINATION SUPERFUND SITE,
SAN BERNARDINO. CALIFORNIA
This section summarizes and responds to all significant comments received during the
public comment period (38 days) on EPA's proposed interim cleanup plan for the Muscoy Plume
Operable Unit of the Newmark Groundwater Contamination Superfund Site in San Bernardino,
California. This summary is divided into two parts. Part 1 provides a summary of the major
issues raised in written comments contained in three letters received by EP A during the comment
period. Part 2 summarizes the questions and comments made during the public meeting on the
Proposed Plan held in San Bernardino on January 10. 1995. Copies of all the written comments
received by EP A are included in the Muscoy Plume OU Administrative Record, available for
review at the information repositories for the Newmark Superfund Site. The transcript of the
public meeting. including all the questions and comments made during the meeting, is .also
available at the information repositories.
1. WRITTEN COMMENTS
1) Commenter (San Bernardino Valley Water Conservation District) emphasizes that. "..it is
imperative that the Muscoy plume. as well as the other contaminant plumes, be cleaned up as
rapidly as possible." Commenter provides estimate of water in storage in the basin an estimate
of volume contaminated. .
EP A response: EP A appreciates this expression of support for the interim action at the Muscoy
plume. Reaction to a hazardous chemical release must balance the need for rapid response with
careful data gathering and analyses. During this project, EP A has maintained a bias toward
timely action (such as the Muscoy Plume Interim Action) and will continue to seek opportunities
to streamline the process.
2) Commenter recommends consideration of spreading the treated water in an existing gravel pit
in the Lytle Creek area as an alternative to reinjection. Commenter notes that reinjection is a
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March 22. 1995
costly alternative.
EP A response: Recharge of treated water to the aquifer will only be considered as a contingencY
in the event that acceptance by water supply agencies cannot be negotiated. EP A expects that
these negotiations will be successful. The Feasibility Study did not identify existing gravel pits
suitable for spreading (recharging) water all year round at the volumes necessary to meet the
objectives of the Muscoy Plume Ou.
3) Commenter (California Regional Water Quality Control Board, Santa Ana Region) expresses
"SUpport for Alternatives 2 "and 3 (Extraction and treatment using Granular Activated Carbon or
air-stripping technology). Commenter also emphasizes the importance of protecting downgradient
water supply wells.
EP A response: EP A appreciates the careful review and expression of support.
4) Cominenter (West San Bernardino Valley Water District) expresses interest in accepting
treated water from the cleanup project at a reasonable price if all federal and state water quality
requirements are met. This letter was forwarded from the City of San Bernardino Municipal
Water Department which is coordinating local water supply agency negotiations to accept treated
water from the Newmark Superfund Site interim remedial actions. .
" .
EP A response: The active participation of local water supply agencies in the Muscoy Plume OU
and the Newmark Superfund Site in general is respectfully acknowledged. Support of the
proposed alternative by the water supply agencies of the community is important in the selection
of the remedy for this Operable Unit.
2. COMMENTS FROM PUBLIC MEETING HELD JANUARY 10. 1995
Lee Brandt (written and oral comment)
5) Commenter notes that he had played around Camp Ono (potential source area) as a child and
has developed serious health problems. Commenter recommends public notice be given to people
who played in the area that they were exposed to carcinogens.
EP A response: This comment is about the source and does not directly address the Muscoy
Plume interim action. The State of California and EP A searched extensively for surface
contamination throughout the potential source area but did not detect any remaining VOCs.
Since the contaminants of concern are quite volatile, it would be unusual to detect any significant
surface contamination even a year or two after the release. Our analyses do not indicate any
current exposure except through untreated groundwater, and the state and local water supply
agencies prevent untreated contaminated water from entering the water supply system. Your
suggestion about addressing past exposures has been forwarded to the Agency for Toxic
Substances and Disease Registry (ATSDR). They have been requested to contact you directly.
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March 22. 1995
Jeff Wright
6) Commenter objects to operation of existing air-stripping towers (at Newmark OU) without
emission control systems in light of possible restrictions on backyard barbecues in the region as
a result of air quality issues.
EPA response: This comment is indirectly pertinent to the Muscoy Plume OU, in that air-
strippers are considered a possible treatment technology for the contaminated groundwater. EP A
has committed to meeting the South Coast Air Quality Management District's emission control
requirements if this technology is used. The existing air-stripping towers at the Newmark and
Waterman wellfields in San Bernardino meet the applicable air quality requirements. Studies
conducted by the City of San Bernardino have concluded that current emissions do not pose a
health hazard. The comparison of risk from the untreated air emissions versus the risk from
partially combusted charcoal from all of the backyard barbecues in San Bernardino is an issue
beyond the scope of this Superfund project.
7) Commenter suggests that permitting of the Newmark air-strippers without emission control
systems is a breakdown of the environmental regulatory process.
EP A response: As noted above, the existing treatment systems in San Bernardino meet the
applicable air quality. requirements. Studies conducted by the City of San Bernardino have
concluded that current emissions do not pose a health hazard. EP A has committed to meeting
the South Coast Air Quality Management District's emission control requirements if the air-
stripping technology is used.
8) 90mmenter feels that regulators have been incapable of preventing the San Bernardino aquifer
from being contaminated by two or more Superfund sites.
EP A response: Aquifers like the one beneath San Bernardino are vulnerable to releases of
contaminants to the soil surface. It is important to recognize that contamination of the aquifer
is believed to have originated more than 20 years ago, from sources that are not likely to reoccur
given current regulation of hazardous substances.
Frank Vera
9) The commenter notes that it is misleading to have separate names for the Newmark and
Muscoy Plume OUs, when the problem is actually the Camp Ono Contaminant Plume.
EP A response: Operable units are discrete actions that comprise incremental steps toward a
comprehensive solution for the entire site. Despite the complexity of the Newmark Superfund
Site geology and the difficulties inherent in investigating groundwater contamination 500 feet
beneath an urban area, EP A was able to show that the Newmark plume and the Muscoy plume
originate from the same area. It has not been established which of several potential sources are
responsible for the contamination, and it would be premature to declare this the Camp Ono site.
10) The commenter feels that EP A has made their presentation as if EP A were doing the public
a favor when EP A is actually required by law to address the contamination. In addition the
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March 22. 1995
commenter believes that there has not been sufficient effort to uncover the real sources
(Manhattan Project, Ethyl Corporation, Kaiser Steel, Culligan Zeolite).
EP A response: The record is clear that EP A is responding to the Newmark site in accordance
with the requirements of the CERCLA statute and the National Contingency Plan (NCP)
regulations. All the potential sources mentioned as well as many others have been considered
by EP A. After analysis of the information gathered to this point, EP A has decided not to pursue
the sources mentioned since the nature of chemical usage, location, time frame of operation or
a combination of these factors are not consistent with the location and nature of the Newmark
Superfund Site groundwater contamination. For example, the Ethyl Corporation facility was
located near the leading edge of the Muscoy plume and the pattern of contamination shows that
the plume originated miles to the northwest of this facility.
11) The commenter asserts that the source is the former military base (Camp Ono) and the
federal government should be cleaning it up. The commenter further states that the source is
actually a major military complex that wraps all around the Shandin Hills and includes a former
Naval hospital northeast of the Shandin Hills.
EPA response: EPA's investigation into the source (the Source OU) is focusing on the general
area of the former San Bernardino Engineering Depot (Camp Ono), although other origins cannot
be ruled out. The pattern of contamination is not consistent with releases from potential sources
north and east of the Shandin Hills. The pattern of contamination is also inconsistent with
releases from the wwn incendiary manufacturing operation southeast of Camp Ono (often
referred to as the "bomb plant").
12) The commenter feels that more emphasis must be paid to a secret pre-Manhattan (nuclear
weapons) military project at the "Bomb Plant Complex".
EPA response: The San Bernardino Engineering Depot (Camp Ono) was an operation of the
Corps of Engineers and the Quartermaster Corps during WWII on land leased from private
parties. EP A has no credible evidence that any secret research went on there. All the wells in
the area show the same low levels of naturally occurring radiation, including wells several miles
upgradient of the depot and in portions of the basin hydrologically isolated from any potential
influence from the depot.
13) The commenter is concerned that the groundwater had been contaminated and people were
exposed to hazardous chemicals for 30 to 40 years because the bomb plant complex was kept
secret.
EP A response: State and local water supply agencies responded immediately when the
groundwater contamination (by VOCs) was discovered as part of a statewide Department of
Health Services initiative to test groundwater for unexpected solvents. The state's investigation
at that time discovered contamination in a number of other basins unrelated to military bases.
See previous responses concerning past exposures (Comment #5) and evidence of military
operations (Comments #9, 11 and 12).
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Muscoy Plwne Record of Decision
Pasze 38
March 22. 1995
John Stevens
14) The commenter feels that EP A has not taken radioactive contamination seriously. since the
Newmark Superfund Site contamination seems like the same problem as Norton Air Force Base
which does have radiation problems and chlorinated solvents together.
EPA response: (See response to Comments #11 and 12 above)
15) The commenter expresses doubt and frustration that the VOC contaminant levels reported
in the EP A Remedial Investigation Report and related sampling reports are in parts per million
rather than parts per billion. The commenter is concerned that the true concentrations are in parts
per million and that these levels would cause problems with adequate treatment. The commenter
reasons that EP A would not be proposing an action if the contaminants were really in the parts
per billion since. "...then it wouldn't be a real problem."
EP A response: All EP A documents show that the contaminant levels of VOCs at the Newmark
Superfund Site have been in the microgram per liter (parts per billion) range. Drinking water
standards for both PCE and TCE are 5 micrograms per liter (parts per billion). EP A is concerned
about contamination at this level and is responding to this release in order to meet the drinking
water standards. .
16) The commenter insists that more effort needs to be expended on explaining what was really
going on at the 2700 acre complex at Camp Ono. He suggests that uranium tetrachloride was
produced at the base. and that the nearby Ethyl Corporation was involved in producing
tetrachlorides and ethylene as well as deuterium needed for nuclear activities.
EP A response: EP A is conducting a thorough subsurface investigation in the Camp Ono area.
EP A is continuing to work with the Department of Defense to provide a more detailed account
of activities at the former depot. The history of the San Bernardino Engineering Depot is
available in the Administrative Record. The Army leased 1600 acres and all leases ended by
1947.. See previous responses concerning radioactivity (Comment #12) and involvement of other
facilities in the area (Comment #11).
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