PB94-964529
EPA/ROD/R09-94/116
September 1994
EPA Superfund
Record of Decision:
Motorola 52nd Street,
Phoenix, AZ,
7/1/1994
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RECORD OF DECISION
OPERABLE UNIT TWO
East Phoenix Groundwater Containment
Motorola 52nd Street Superfund Site
Phoenix, Arizona
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I. DECLARATION
1.
Site Name and Location
Motorola 52nd Street
Phoenix. Arizona
2.
Statement and Basis of Purpose
This Record of Decision (ROD) presents the interim remedial action the Arizona Department
of Environmental Quality (ADEQ) and the United States Environmental Protection. Agency
(EP A) have selected for Operable Unit Two at the Motorola 52nd Street site in Phoenix,
Arizona. This document was developed in accordance with the Comprehensive Environmental
Response. Compensation. and Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA), and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is
based on information contained in the Administrative Record for the. site.
3.
Assessment of the Site
Actual or threatened releases of hazardous subs~ces from this site. if not addressed by
implementing the response action selected in this ROD, may present an imminent or substantial
endangerment to public health, welfare, or the environment.
4.
Description of the Selected Remedy
This Record of Decision is for Operable Unit Two at the site. which is an area of contaminated
groundwater downgtadient of Operable Unit One. In comparing and selecting remedial
alternatives for Operable Unit Two, effective and continued operation of Operable Unit One was
assumed. The selected remedy is an interim remedy designed to address groundwater that is
contaminated with volatile organic compounds (VOCs). The major components of this remedy
consist of:
o
Extraction of groundwater in the vicinity of Interstate 10 and Van Buren Street.
o
"
Treatment of extracted water near extraction locations by either air stripping with
off-gas treatment by synthetic resin adsorption, or advanced oxidation based oil
fInal design considerations.
o
Injection of treated water back into the aquifer in locations allowing additional
control of the contaminant plume.
These remedial actions address the principal threat and primary risk at the Motorola 52nd Street
site by establishing a capture zone across the entire width and depth of the contaminant plume
and by removing and permanently destroying the contaminants from the groundwater. These
actions will signifIcantly reduce the toxicity. mobility. and volume of hazardous substances in
. the groundwater at the site.
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s.
Statutory Determinations
This interim action is protective of human health and the environment, . complies with Federal
and State applicable or relevant and appropriate requirements for this limited-scope action, and
is cost-effective. Although this interim action is not intended to fully address the statutory.
mandate for permanence and treatment to the maximum extent practicable, this interim action
does utilize treatment and thus is in furtherance of that statutory mandate. Although this action
does not constitute a fmal remedy for the Motorola 52nd Street site, the statutory preference for,
remedies that employ treatment that reduces toxicity, mobility, or volume as a principal element
is satisfied by this remedy. Subsequent actions are planned to address fully the threats posed
by the conditions at this site. Because this remedy will result in hazardous substances remaining
on site above health-based levels, a review will be conducted within five years after
commencement of the remedial action to ensure that the remedy continues to provide adequate
protection of human health and the environment. Because this is an interim action ROD,
review of this site and of this remedy will be ongoing as ADEQ continues to develop final
remedial alternatives for the site.
-~
~~ .
~ward Z. Fox, Director
Arizona Department of Environmental Quality
Jt2'
W \.4A-
Jo Wise
Deputy Regional Administrator
USEPA
Region IX
7-I-qt{
Date
7.'2-I.'Y
Date
2
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n. DECISION SUMMARY
1.
Site Name, Location and Descripti!>n
The Motorola 52nd Street site is located in Phoenix, Arizona. Activities at this Superfund site
began with the investigation of releases of hazardous substances from the Motorola, Inc.
Semiconductor Products Plant at 5005 East McDowell Road, in the eastern portion of Phoenix,
Arizona, in Maricopa County. Figure 1 shows the location of the Motorola plant within the
Phoenix area. Investigations of this facility and investigations under Arizona's Water Quality
Assurance Revolving Fund (wQARF) program have identified other potential sources of
groundwater contamination. The combined releases from known and suspected sources have
created extensive groundwater contamination in the area. Figure 2 shows the current known
extent of trichloroethylene (TCE) contamination. As the figure indicates, the western edge of
the contaminant plume has not yet been identified, but extends well beyond 7th Avenue. Other
contaminants are also present; however, the known areal extent of TCE contamination
reasonably encompasses the other contaminants.
The 90-acre Motorola facility is zoned for industrial use and surrounded by a mixtUre of light
industrial and residential properties. The nearest residences are less than 100 feet from the
western property boundary. Major geographic featUres are the Papago Buttes to the east of the
plant, the Salt River flowing westerly about one mile to the south, the Old Crosscut Canal
located along 46th Street, and the Grand Canal which flows northwesterly through the area west
of 40th Street and Van Buren Street. Phoenix Sky Harbor Airport is located approximately 1.5
miles to the southwest. The Papago Military Reservation, a 3f4 square mile facility used by the
Arizona National Guard, is located northeast and east of the plant. There are no critical
habitats, wetlands, endangered species, or known historic sites in proximity to or affected by the
site. This site is not sitUated in a flood plain.
The Motorola plant lies near the eastern margin of the west basin of the Salt River Valley. The
area is underlain by alluvium, but because of the proximity of the plant to the nearby bedrock
outcrops at the Papago Buttes, bedrock occurs at a relatively shallow depth. In monitor wells
at the east boundary, bedrock was encountered at a depth of 20 to 30 feet below the ground.
The thickness of the alluvium increases to the west. On the western boundary of the plant, the
thickness of alluvium is greater than 60 feet at some locations. Farther to the west, the thickness
of the alluvium continues to increase. At the Old Crosscut Canal, the alluvium is approximately
80 to 90 feet thick, and at a monitor well on 36th Street, about 2 miles west of the plant, the
thickness of the alluvium is more than 200 feet.
The direction of regional groundwater flow, both in the alluvium and the bedrock, in the vicinity
of the Motorola plant is predominantly from the northeast to the southwest, although local
variations in this overall pattern are present. This pattern was not found to vary significantly
during the course of the initial Remedial Investigation/Feasibility StUdy (RIfFS). From the mid-
1950's until 1980, the direction of groundwater flow west of the plant may have had a more
northerly component than it has had in more recent years.
The Motorola facility is paved and consists of several large buildings used for the production
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Figure 1. Site Vicinity Map
4
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Figure 2.
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Current extent of TCE contamination in groundwater
East Washington Groundwater Contam.ination Map
ADEQ Sweep Sam.ple Event #2 Oct - Dee 1992
Triehloroethene (TCE)
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of semiconductors, for the storage of product and chemicals, and for administrative purposes.
The facility also contains a reverse-osmosis/deionization plant that produces ultra-clean water
for the manufacturing process, cooling towers for the facility, and large parking areas for
employees. The soil vapor extraction equipment and the Integrated Groundwater Treatment
Plant for treatment of extracted groundwater, constructed as part of the remedy for Operable
Unit One, are also on the facility property. Figure 3 shows major buildings and features.
2.
Site History and Enforcement Activities
The Motorola 52nd Street facility was originally constructed in 1956. Prior to that time, the
location was largely agricultural. In 1982, Motorola discovered a solvent leak at an underground
storage tank. Motorola notified the Arizona Department Of Health Services (ADHS) and
initiated a Preliminary Investigation for potential soil and groundwater contamination. The
report of the Preliminary Investigation, which was published on December 9, 1983, indicated
soil and groundwater contamination at the plant and groundwater contamination to the west of
the plant. As a result of these fmdings, Motorola entered into a oral agreement with EP A,
ADHS and the Arizona Department of Water Resources (ADWR) to characterize the
environment near the plant, identify the nature and extent of contamination and recommend
remedial actions. Potential sources of contamiDation include past surface discharges, spills, tank
and pipe leaks, and discharges to leach fields and dry wells.
Based on conservative assumptions, it is estimated that Motorola disposed of approximately
200,000 gallons of chlorinated solvents at the plant between the late 1950s and 1983. It is
estimated that TCE was disposed of in the greatest quantity (116,000 gallons), followed by
trichlorotrifluorometbane (57,000 gallons), and xylenes (26,000 gallons). The amount of
trichloroethane (TCA) which Motorola disposed or leaked is estimated at approximately 8,000
gallons. Some toluene and tetrachloroethylene (PCE) were also disposed at the plant.
ADEQ accepted Motorola's Remedial Action Plan for Operable Unit One in a Letter of
Detennination on September 27, 1988. EPA's concurrence with that Letter of Detennination
was fonnalized in a Record of Decision signed on September 30, 1988. A Consent Decree was
executed in July 1989 between ADEQ and Motorola for the design and implementation of the
remedy for Operable Unit One. The Consent Decree also committed Motorola to additional
remedial investigation and feasibility study work.
Operable Unit One (OUl) addresses organic solvents in soils and alluvium.groundwater. The
facilities for containment of on-plant and near-plant groundwater CODt.amination" have been in
operation since May 1992. The on-plant soil vapor extraction (SVE) treatment system has been
in operation since April 1992.
Three companies other than Motorola received General Notice letters in late 1992 notifying them
of their potential liability at the site. These companies are AIliedSignal Corporation, lIT
Cannon. and Tiernay Turbines. The City of Phoenix also received General Notice as the
property owner for the AlliedSignal and ITT Cannon facilities. The locations of these facilities
can be seen in Figure 2. These facilities were determined to be potentially responsible parties
(PRPs) for the groundwater contamination as a result of investigations conducted under the State
of Arizona's Water Quality Assurance Revolving Fund (wQARF) program.
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SOURCE: DatIIH & Moore Draft Rl, 1987
McDowell Road
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Volatile organic compounds (VOCs) in concentrations exceeding drinking water standards (also
referred to as Maximum Contaminant Levels, or MCLs) have been detected in groundwater as
far southwest as 75th Avenue and Van Buren Street. A coordinated "area sweep" groundwater
quality sampling event that included the Motorola wel1s and wel1s in the East Washington
WQARF investigation area took place in April, May and June, 1992. A second sweep was
conducted during November and December 1992. TCE contamination has been identified by
ADEQ as shown in Figure 2. The contamination extends beyond the East Washington area and
into the West Van Buren WQARF area, to approximately 75th Avenue. Figure 4 shows the
location of groundwater contamination projects near the Motorola 52nd Street site. In Spring
of 1993, ADEQ and EPA decided to develop a second operable unit instead of a final remedy
because of the extent of groundwater conf:amination.
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CONTAMINATION PROJECTS
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Figure 4.
Area Groundwater Contamination Projects
Motorola conducted on-plant and off-plant soil gas testing in 1984 and 1985. ADEQ conducted
soil gas testing in a residential area west of the Motorola 52nd Street facility in March 1992.
The Arizona Department of Health Service's (ADHS) interpretation of the 'soil gas data
concluded that the level of volatile organics in the soil gas does not present a current risk to
human health. Additional soil gas sampling was done in July 1992, and results were consistent
with the previous sampling data.
A Baseline Risk Assessment was completed by ADHS in November 1992. Groundwater and
soil gas data were used in the assessment. Section 6 of this Record of Decision describes the
risk assessment in more detail.
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In October/November 1990, TCA was detected at 5100 parts per billion (Ppb) in monitor well
DM 201 in the Southwest Parking Lot (SWPL) area of the Motorola 52nd Street plant. Further
studies, including soil gas testing and soil and groundwater investigations, revealed a separate
source of contamination from the sump of the Chemix room of Building A-D. Concentrations
of both TCA and 1,1 dichloroethene (DCE) in the groundwater and soil gas increased
significantly in the SWPL area during the period from 1989 to 1991. Groundwater
contamination extends at least 150 feet from the plant to the southwest of the parking lot, but
has not been detected at well DM 733, located approximately 600 feet downgradient of the
parking lot. Groundwater contamination from the SWPL area is not currently believed to merge
with the larger contaminant plume. There are over 24 on-plant and off-plant wells in the SWPL
monitor well network. Extraction wells have been installed along the south boundary of the
parking lot. The purpose is to create a capture zone sufficient to prevent further off site
migration of contaminated groundwater. Water pumped from this area is treated at the currently
operating OUI groundwater treatment plant on the Motorola plant. Wells continue to be
installed to identify the extent of cont.amin~tion in this area. Ongoing remedial actions in the
SWPL area will be considered during development of fmal remedy alternatives for the Motorola
52nd Street Superfund site.
3.
Community Participation
After construction of the treatment facilities for Operable Unit One, ADEQ conducted a variety
of community involvement and education activities. In March 1992, when ADEQ was
conducting soil gas investigations, a fact sheet was distributed to describe activities occurring
at the site. During the summer of 1992, another fact sheet was distributed after the soil gas data
had been evaluated by the Arizona Department of Health Services. A fact sheet was distributed
during the summer of 1993 after ADEQ compiled data from this project and the East
Washington Water Quality Assurance Revolving Fund project and created a series of contour
maps (similar to Figure 2) outlining the immense area of apparently continuous groundwater
contamination.
During most of 1992, ADEQ met regularly with a citizens' committee to discuss current
activities and clarify technical issues. The meetings were held generally once a month, although
the first few were more frequent. A variety of issues were discussed during these meetings,
including soil gas, risk assessments, private wells, drinking water, and data requirements.
An informational meeting was held in December 1991 to discuss a variety of issues with the
community. In July 1993, ADEQ held a series of open houses at several locations within the
site to explain the recently-completed CODtaminant contour maps.
The Gateway Neighborhood Coalition has received a Technical Assistance Grant fr.om the EP A.
The grant has allowed the group to hire a technical advisor to help them understand the technical
issues about the site. The technical advisor is attending meetings held by ADEQ with potentially
responsible parties. . .
The public comment period for the Remedial Investigation! Feasibility StUdy and Proposed Plan
for Operable Unit Two was announced January 5, 1994 by notice in the Arizona Republic
I newspaper. The comment period was to extend to February 4, 1994. A timely request from
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the Gateway Neighborhood Coalition caused ADEQ to extend the comment period until March
7, 1994. Notice in the Arizona Republic newspaper on February 4, 1994 and a brief fact sheet
announced the extension of the comment period. Due to combined requests from Potentially
Responsible Parties and the Gateway Neighborhood Coalition on February 25, 1994, the public
comment period was extended a second time to April 6, 1994. Notice of this extension appeared
in the Arizona Republic newspaper on March 9, 1994. Two availability sessions (Open House
style meetings) were held on January 25 and 27, 1994. The public meeting to take oral and
written comments was held on February 3, 1994. A response to comments received during the
public comment period is included in the attached Responsiveness Summary prepared by ADEQ.
4.
Scope and Role of Operable Unit Two
This is the second operable unit (OU) initiated by ADEQ to date. As part of the remedy for
OUI selected in the 1988 ROD, Motorola has begun clean-up of groundwater near the 52nd
Street plant to reduce the risk from and migration of the contamination. This second OU
addresses groundwater contamination in eastern Phoenix in the area west of the Old Crosscut
Canal and east of Interstate 10. The available data indicate the presence of groundwater
contamination in this area at levels well above drinking water standards and are sufficient to
determine the approximate size and location of the needed action. ADEQ is confident the
selected remedy for this OU represents a significant step toward cleanup of the area and will not
be inconsistent with, or preclude implementation of, a fmal remedy. ADEQ has not yet selected
a fmal remedy for the Motorola 52nd Street site, but the fmal remedy is expected to include, at
a minimum, limiting contaminant migration in this and other highly contaminated areas of the
site.
OU2is classified as an interim action to reflect the possibility that additional remedial actions
in this area may be needed. ADEQ will use information collected during operation of the
selected remedy to help determine the need for additional actions and the nature of the fmal
remedy.
The primary purpose of this response action is to establish a capture zone across the entire width
and depth of the contaminant plume in the area of Interstate 10. . A secondary purpose is to
reduce contaminant concentrations within the alluvial aquifer upgradient of the extraction wells.
Also, additional hydrogeologic data collected during this interim action will facilitate
development of additional remedies. This ROD establishes additional interim measures to
control the contamination. Groundwater will be extracted and treated to a level at or ~l~w
Maximum Contaminant Levels (MCLs). Reinjection of the treated water will enhance hydraulic
control of the plume. This interim action will be consistent with future actions, to the extent
practicable.
5.
Site Characteristics
The Motorola 52nd Street site CODtamination. consists primarily of VOCs including TCE,
tetrachloroethylene (PCE) , trichloroethane (TCA), and associated degradation products, including
vinyl chloride. Arsenic and fluoride also occur above background levels west of the Motorola
plant. This area of contamination is not currently used as a source of drinking water; however,
. the area could potentially be used as a drinking water source.
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Levels of contamination beneath the Motorola facility have been detected as high as 4,000,000
ppb of TCE. The presence of non-aqueous phase (pure product) liquids has been detected in
wells on the Motorola plant. Operable Unit One is intended to contain these high levels of
contaminant east of the Old Crosscut Canal at 46th Street. However, an apparently continuous
area of groundwater contamination extends west-southwest to 7th Avenue and beyond (see
Figure 2). The western boundary of the contaminant plume lies within the West Van Buren
WQARF area and has not yet been identified. Potential releases at AlliedSignal, lIT Cannon,
and Tiernay Turbines, as well as other facilities, may also be contributing to the groundwater
contaminant plume that begins at the Motorola plant at 52nd Street.
The contaminants of potential concern for this operable unit are those hazardous substances that
demonstrate toxic effects to human health and the environment, persist at levels above the health-
based standards, and are consistently detected. The contaminants of potential concern are TCE,
PCE, TCA, and their associated degradation products including vinyl chloride. Fluoride and
arsenic exist near the plant above background levels, however these will not be addressed as part
of this interim remedy. Inorganic contaminants will be addressed as part of the fInal remedy
for the site. The contaminants of potential concern for this operable unit are known or suspected
human carcinogens.
6.
Summary of Site Risks
The Arizona Department of Health Services (ADHS) prepared a Baseline Risk Assessment for
the Motorola 52nd Street Facility in November 1992. This Risk Assessment characterized the
current and potential threats to human health assuming no action were taken to remediate the
contamination. The Risk Assessment analyzed potential threats from contaminants in the
groundwater, contamjnants in the soils, and contaminants released from the soils. For the
groundwater risk calculations, ADHS used comprehensive organic priority pollutant and
inorganic chemical data from groundwater samples taken from 54 monitoring wells in alluvium
and/or bedrock. Analyses of groundwater samples from soil borings which encountered
groundwater were included where possible. The Risk Assessment does not include evaluation
of data from wells installed and sampled since early 1992. Figure 5 shows the area studied in
the Risk Assessment, and the monitor wells used.
Contaminants of potential concern
The Baseline Risk Assessment identified the compounds in Table 1 as chemicals of potential
concern for the Motorola 52nd Street site, based upon review of water quality analyses from the
wells. Chemicals were placed on the list if they were detected at levels greater than background
levels; were considered a potential threat to human h~alth; were detected in at least one monitor
well; and the highest level detected exceeded MCLs or Health-Based Guidance Levels (HBGLs),
or the chemical is a possible, probable or suspected human carcinogen.
The selected chemicals were designated "chemicals of potential concern" and were included in
the computation of health risk.
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Well Boring and Sample Locations used in the 1992 Risk Assessment
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Table 1. Chemicals of Potential Concern, and range of concentrations detected
Chemical Min. Detected Max. Detected
.. .INORGANiC~CAI.S.(~ffi:d mpaTUpeihijiiion) ...
Arsenic 0.005 2.6
Boron 0.14 7.5
Cadmium 0.005 0.024
Chromium (VI) 0.07 0.15
Chromium (rota!) 0.01 0.24
Cyanide 0.01 0.21
Fluoride 0.2 25
Lead 0.002 0.08
Manganese 0.01 8.13
Nickel 0.02 0.22
Nitrate 0.37 92
Silver 0.1 . 0.1
.
Sulfate 9 3400'
Thallium 0.0009 0.014
Zinc 0.01 2
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< ()RGANi'C cHEMICALs (rqlorUidinPai1Silel: billiOn), :,. ,:. ..... ~......
Benzene 2.3 2.3
Bromodichloromethane 0.26 314
Carbon Tetrachloride 0.3 0.6
Chlorobenzene 0.3 1300
Chloroform 0.2 1500
Chloromethane 2.1 14
Dibromochloromethane 0.2 1.1
1,2-Dichlorobenzene 0.88 5600
1,l-Dichloroethane 0.09 1300
1,2-Dichloroethane 0.2 1500
1,4-Dichlorobenzene 36.9 36.9
1,2 &. 1,4-Dichlorobenzene 0.2 65000
1,l-Dichloroethylene 0.3 26600
1,2-Dichloroethylene 0.2 7000
Dichloromethane 2.7 170000
trans-l.3-Dichloropropene 17.9 17.9
Tetrachloroethylene 0.2 30000
1,1 ,I-Trichloroethane '0.2 330000
1,1,2- Trichloroethane 4 4
Trichloroethylene 0.2 4100000
Vinyl Chloride 1.4 20000
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A review of water quality data from wells that were included in the January 1993 Quarterly
Report prepared by Motorola shows no additional compounds above MCLs or HBGLs in the
expanded well area.
]EXJPosure AssessDOent
. The second step of the Risk Assessment identified possible exposure pathways. An exposure
pathway is considered cODOplete when a cheDOical of concern contacts a receptor (person). In
the Baseline Risk AssessDOent for the.Motorola 52nd Street site, potentially exposed populations
are residents living near the facility and workers at the facility. ADHS determined that the
possible exposure pathways include ingestion, inhalation, and derDOal contact with contaDOinated
groundwater, and inhalation of vapors from soils.
Currently, there are no private or public drinking water wells supplying drinking water froDO the
known area of groundwater contaDOination. . One private well northwest of the facility, 4626G,
has been used for f1lling a swinuning pool and residential irrigation. Well 4626G was also
reportedly used for indoor dODOestic use for approximately six months during 1989 to 1990. One
irrigation well, SRP well 18E-5N, periodically supplements water in the Grand Canal with
groundwater from the area. Groundwater quality data for 54 wells sampled throughout the area
between 1988 and 1991 were used to calculate potential exposure concentrations froDO
groundwater. Table 1 shows the range of concentrations detected in wells tested during this
period for the cheDOicals of potential concern.
Vadose zone reDOediation is not a goal of this interim action, and therefore exposures to
contaDOinated soils or soil gas are not addressed in detail in this swmnary of site risks. Potential
exposure to soil gas vapors was calculated for three groups: on-site outdoor workers; on-site
indoor workers; and area residents. The potential for health effects to nearby residents through
exposure to soils or soil vapors was deterDOined to be insignificant.
The Risk Assessment calculated the average and the reasonable DOaximum exposures by ingestion
or inhalation of the contaDOinants. Major exposure assuDOptions are sumDOarized in Table 2.
ToxicitV AssessDOent
The next step of the Risk Assessment was to deterDOine the carcinogenic and non-carcinogenic
toxicity of the contaIninants of potential concern. Risk was calculated differently for
carcinogenic and non-carcinogenic risks.
Carcinogenic Effects
EPA's Carcinogenic Assessment Group developed cancer potency factors (CPFs), also called
Slope Factors, to estimate excess lifetime cancer risks associated with exposure to potentially
carcinogenic chemicals. Slope Factors (SF), which are expressed in units of (mglkg-day)"l, are
multiplied by the estimated intake of a potential carcinogen, in mglkg-day, to provide an
upper-bound estimate of the excess lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate of the risks calculated from
the SF. Use of this approach makes under-estimation of the actual cancer risk highly unlikely.
14
-------
Table 2.
Major Exposure Assumptions in Risk Calculations
Exposure Factors
Intake value (adult)
parameter . average reasonable maximum
Body Weight 70 kilograms 70 kilograms
Years in lifetime . 70 years 70 years
Ingestion rate (water) 2 liters/day 2 liters/day
Inhalation rate (air) 20 cubic meters/day 20 cubic meters/day
Exposure frequency
Exposure duration.
350 days/ye~
9 years
350 days/year
30 years
, .' . n....'..' ....' .. ...
. n., "'" ....... "',..'" ..""" . ". ... "d.,., ... .' ...." .... "'
. ""'" "..." ...."" .' n. ""'..." ... .-......... ....." ......"
. ... .. "'" ...,.' ........... .... -.,. '""".."'" ."'''''' "......
...bccupa#o@...a&.(iIiclo()iAA4~ijt4obr)/
Exposure time
Exposure frequency
Exposure duration- .
Exposure time
Exposure frequency
Exposure duration-
Exposure time
Exposure frequency
Exposure duration-
"...
.......
..q...
.. ...."
.....' .... .'
"-P'
..... ..
...
.. ....
. .. .
.....
......'"
.. on
4 hours/day
250 days/year
/
9 years
8 hours/day
250 days/year
30 years
16 hours/day
350 days/year
9 years
24 hours/day
350 days/year
30 years
. Carcinogenic effects arc averaged over a 70 year lifetime, while non-carcinogenic effects arc
averaged over the exposure duration listed in the table.
15
-------
Cancer potency factors are derived from the results of human epidemiological studies or chronic
animal bioassays to which animal-to-human extrapolation and uncertainty factors have been
applied.
Slope factors were obtained from EPA's on-line Integrated Risk Information System (IRIS) and
Health Effects Assessment Summary Tables databases.
Non-Carcinogenic Effects
EPA developed reference doses (RIDs) for indicating the potential for adverse health effects
from exposure to chemicals exhibiting noncarcinogenic effects. RIDs, which are expressed in
uni~ of mg/kg-day, are estimates of lifetime daily exposure levels for humans, including
sensitive individuals, who are likely to be without an appreciable risk of deleterious effects
during a lifetime. Estimated intakes of chemicals from environmental media (e.g., the amount
of a chemical ingested from contaminated drinking water) can be compared to the RID. RIDs
are derived from human epidemiological studies or anima} studies to which uncertainty factors
have been applied (e.g." to account for the use of animal data to predict effects on humans).
Risk Characterization
Risks, both current and potential, are characterized and evaluated utilizing' exposure and
toxicology information. Risk characterization is presented in both quantitative andlor qualitative
format. When data are available, quantitative risk characterizations are performed and evaluated
qualitatively. Risk estimation methods used in the risk assessment proceed from estimation for
a single compound and exposure route, to a summation of risk for all chemicals of concern for
a given route, and culminating with a summation of risk across exposure routes.
Carcinogenic risk is calculated as the incremental probability of an individual developing cancer
over a lifetime (70 years) due to exposure to a carcinogenic compound. This is also referred
to as incremental or excess lifetime cancer risk (ELCR) and represents the increased risk of
developing cancer above the background rate, estimated at about 3 x 10"1 (30%). Non-
carcinogenic effects include neurotoxic, hepatotoxic, nephrotoxic, teratogenic, and reproductive
reactions, and any other noncancer related systemic toxic responses. The potential for an
individual suffering a noncarcinogenic effect is not expressed as a probability, but as a ratio or
quotient. The hazard index is the ratio of an exposure level over a specified period (CPI) ta the
chemical specific reference dose (RID) which is not expected to produce toxic effects over the
period of concern.
A well-by-well approach was taken due to the large area covered by the monitor'wells and the
large differences in concentrations of chemicals over that area. The potential ingestion risk,
cancer hazard index, and systemic hazard index were calculated for each chemical of concern,
on a well-by-well basis. A well total for each category was determined by summing the entries.
Table 3 presents the range of calculated potential ELCR and non-cancer hazard indices under
average and reasonable maximum exposures.
16
-------
Table 3.
Range of calculated potential ELCR and non-cancer hazard indices under.
average and reasonable maximum exposures
Average Exposure Reasonable max. exposure
minimum maximum minimum maximum
ELCR 8xl0"7 (well lxl0"2 (wells 3xl
-------
action to date has reduced site risk, but groundwater contamination at the site still exceeds
Maximum Contaminant Levels and warrants additional remedial action.
7.
Description of Alternatives
The specific objectives for the interim remedial action in Operable Unit Two are to establish a
capture zone across the entire width and depth of the contaminant plume, and to begin to remove
contaminants from the groundwater for eventual restoration of the aquifer as a potential source
of drinking water. The remedy for OU2 is an interim action. Accordingly, the remedy does
not include aquifer remediation standards or a restoration timeframe. A final remedy for the
entire Motorola 52nd Street site will be developed after further investigation to defme the extent
of groundwater contamination.
The Interim Remedy FeasibilitY Study (lRFS) for Operable Unit Two, and the supplement to the
IRFS, evaluated seven alternatives. These alternatives are briefly described below. The
alternatives are further briefly explained in the "Proposed Plan for the Motorola 52nd Street
Superfund Site" completed by ADEQ in January t994.
No Action Alternative
The Superfund program requires that a "No Action" alternative be evaluated at every site as a
baseline for comparison of other cleanup alternatives. Under this alternative, no further action
(beyond continued operation of the existing OUt containment system) would be taken to limit
migration of contaminated groundwater. Five additional monitoring wells would be installed to
defme and monitor the extent of groundwater contamination downgradient of OUt. The
monitoring program would include water level measurements and analysis of water samples on
a quarterly basis.
Costs associated with the No Action alternative are considered base costs and thus no
comparison is made with other alternatives.
Alternatives 11. l1C. 21. MR. and MC
The numbers describing the alternatives in this Record of Decision are consistent with those used
in the Interim Remedy Feasibility Study, the IRFS supplement, and the Proposed Plan to allow
easy reference to those documents. Charts describing these alternatives appear underneath
Figure 6 and in Table 4.
The five alternatives described below all include groundwater extraction, treatment of extracted
water, disposal of treated water via a beneficial end use, and the installation of additional
monitoring wells. Each of the alternatives was developed and evaluated assuming continued
operation of the eXisting OUI groundwater containment system. Treatment. of the extracted
groundwater for removal of VOCs will be accomplished using either air stripping (with treatment
of air emissions and off-site incineration of recovered solvents) or advanced oxidation (which
uses ultraviolet light to destroy VOCs). These two technologies are discussed in detail in the
IRFS. ~oth are considered to be established, reliable technologies for removal of the VOCs of
18
-------
concern at this site. Depending on location of the treatment plant, each has advantages over the
other. Selection of the preferred technology will therefore be made during remedial design. For
the purpose of calculating the costs of each alternative, it was assumed that air stripping would
be the selected technology for VOC removal.
The differences between the alternatives are mainly 1) the location where groundwater extraction
would take place and 2) what the beneficial use of the treated water would be. The amount of
contaminants removed over time also differs between alternatives. A computer model was used
to determine the pumping rates that would result in effective capture of the plume at each
alternative location. Figure 6 shows the generallc,>Cation of the line of extraction wells for each
of the alternatives and the resulting capture zone.
The IRFS also includes a detailed description and evaluation of alternative 64, in which
groundwater would be extracted near Interstate 10, treated for VOCs and discharged to an
existing stormwater drain leading to the Salt River. This discharge option was subsequently
determined to be inconsistent with the requirement for beneficial end use, and the alternative was
eliminated from further consideration.
Alternative 11 - Extraction at the Grand Canal. treatment for VOCs and Fluoride. and
Reiniection
This alternative would provide containment of contaminated groundwater in the area of the
Grand Canal. Extraction wells would be located along the east side of the Grand Canal and
injection wells would be located east of the Grand Canal.' Some injection wells would be located
along the north and south edges of the plume to keep contaminants from moving in those
directions, and others would be located in the central portion of the plume.
Groundwater would be extracted at a rate of approximately 2800 gallons per minute and treated
for VOCs and fluoride to meet drinking water standards. Fluoride would be removed from the
water using activated alumina adsorption, in order to meet treatment standards for reinjection.
The calcium fluoride sludge generated by the activated alumina process would be disposed of
in a landfill.
The capture zone would contain appro~ately 0.7 additional square miles of the contaminant
, plume beyond OUI. The treatment system would remove approximately 800 gallons of TCE
from the aquifer over a 20 year period. (Gallons of TCE removed is supplied for compa~son
purposes. Other VOCs would also be removed.) The capture zone (see Figure 5) will be
achieved within one year of system start-up.
Capital costs for this alternative are estimated to be $11,950,000 and annual operation and
maintenance (O&M) costs are $2,450,000. The present value is calculated to be $40,000,000.
A large part of this cost is associated with the fluoride treatment technology (approximately 25 %
of capital costs and 45 % of. annual O&M costs).
19
-------
Figure 6. Alternative containment lines and features
I
.
. '.
.- --1\~
I
I
I
E
;:zr
~o&'HiGK
-eei(f~MOO'~
(ALTERNA11VE 21)
CN"MIE DE
..-...
-
ICMI: II FU1
-
NO ACTION ALTERNATIVE 11 ALTERNATIVE 11 C AL TERNA T1VE 21 AL TERNA T1VE 84C ALTERNATIVE 84R
Eztractlon at GI'8ftIf Ex1ractkmatGnind Eztractlon at Extncdon at Extr8ct1on at P8pago
C8n81. r8InjKtIon C8n8l. dIach8"a to I8droCk HIgh. P8p8go Fr88wIY. Fr88way. nInj8e1Ion
Gr8nd C8n8I NInjectIon chdI8rg8 to Gnnd
C8n8I
Estimated No. of 5 . monitoring' 4 - Ixtraction 4 - axtrlction 8.iirtraction 2 . axtrlction 2 . Ixtrlction
NewW'" 1 2 . Injection 7. monitoring 9 - Injecticln 8 - monitoring 15 . Injection
7. monitoring 7 . monitoring 8 - monitoring
Treltment no additional' 2800 gallona par 2800 gaDona par 1800 glnona per 4000 gl.ons par 4000 JllaUona per
C8p8c!ty C8p8C!tv mlnuta minute minuta minutl .. minute
0Wr8II No Iddltionel 0.7 sqUire m8e 0.7 squire mill 1.5 squire mile 2.6 sqUire mil 2.6 squsre m8e
Protlct1ven888 containment containment ar88 containmant lrea containment arel COntllnment Ir88 contlinment lrea
ContamIn8nt8 VOCI Ind fluoride vOCa VOCs vOCa voel
Treltld
ReductIon of 250 glnona of 800 gaDona of TCE 850 ganona of TCE 1350 ganons of 2250 gallona of 2000 gallon. of TCE
Toxicity. Mob8ty. TCE ramoved by removed In 20 removed In 20 yelll TCE removed In 20 TCE removed In 20 removed In 20 yeall
or VoIum8 OU1 In 20 Ylall years years yelll
ttmIugh
Tre8t/MIII
2().year COlt ba.. cosua .40.000.000' .18.000.000 t21.ooo.ooo t28.ooo.000 t31.ooo.ooo
!pre.ant V81u81 ,.,
, Number of monitor walll for No Action Ire part of. not In addition to. those IiItad for the ramaining altarnetiva..
I Element. of the No Action Alternative are constsnt for aO altemative.. other COlt. IIstad Ire above and tieyond the.. com.
a Trea1m8nt of fIuorida in Altarnative 11 Is a large portion of the coat.
20
-------
Alternative llC - Extraction at Grand Canal. Treatment for VQCs. and Discharee to the
Grand Canal
This alternative is similar to Alternative 11. Extracted water would be treated for VOCs only,
and the treated water would be discharged into the Grand Canal for inigation use instead of
being injected back into the ground. No treatment for Duoride would be conducted because
fluoride concentrations in extracted groundwater would not exceed standards applicable to
irrigation water.
The capture zone would contain approximately 0.7 additional square miles of the cont.aminant
plume, and remove approximately 850 gallons of TCE from the aquifer over a 20 year period.
(Gallons of TCE removed is supplied for comparison purposes. Other VOCs would be also be
removed.) The capture zone (see Figure 6) will be achieved within one year of system start-up.
For approximately one month every year, discharge to the Grand Canal will not be allowed
while the canal is drained for maintemmce. During this period, containment, primarily along
the peripheries of the capture zone, will be lost. If the effects of the one-month shutdown on
maintaining containment are unacceptable, alternatives (such as reinjection) are available to allow
the extraction system to continue to operate. However, the additional costs of such discharge
alternatives are not included in the cost figureS described below.
Capital costs for this alternative are estimated to be $3,780,000 and annual operation and
maintenance costs are $1,260,000. The present value is calculated to be $19,000,000.
Alternative 21 - Extraction at the Bedrock Hi~h. Treatment for VOCs. and Reinjection
An area of elevated bedrock, referred to in the Interim Remedy Feasibility Study as a Bedrock
High, exists oriented southeast to northwest near 32nd Street and Washington. The location is
near the proposed location of extraction wells seen in Figure 6. This alternative is designed to
make use of this geologic feature to aid the containment of the contaminants. Groundwater
extraction would occur near the Bedrock High, and injection of the treated water would occur
east of the Bedrock High. Some of the injection wells would be along the northern edge of the
plume to keep the plume from moving in that direction, and others would be in the central
portion of the plume. The extracted water would be treated for VOCs to meet drinking water
standards. Inorganics in this extraction area do not occur at levels that would require treatment
before reinjection or discharge to surface water.
Additional information regarding the bedrock high was collected by Motorola after completion
of the Interim Remedy Feasibility Study. This information indicates that the effectiveness of
Alternative 21, as configured in the feasibility study,. would be dramatically reduced.
The extraction and treatment system would contain approximately 1.5 additional square miles
of the contaminant plume and remove approximately 1350 gallons of TCE from the aquifer over
a 20 year period. (Gallons of TCE removed is supplied for comparison purposes. Other VOCs
would also be removed.) The capture zone (see Figure 5) will be achieved within one year of
system start-up.
21
-------
Capital costs for this alternative are estimated to be $7,000,000 and annual operation and
maintenance costs are $1,160,000. The present value is calculated to be $21,000,000.
Alternative 64R - Extraction near 1-10. Treatment for VOCs. and Reinjection
This location for a containment line represents the western edge of the area originally studied
for .a fmal remedy. There is sufficient hydrogeologic characterization to support remedial
actions up to Interstate 10. Extraction wells would be Joeated near Interstate 10. The extracte~
water would be treated fOT VOCs to meet drinking water standards. Inorganics in this extraction
area do not occur at levels that would require treatment before the beneficial use. The treated
water would be injected back into the ground. Some of the injection wells would be located east
of Interstate 10 at the northern edge of the plume to keep contaIIlinai1ts from moving in that
direction, and others would be in the central portion of the plume.
The extraction and treatment system would contain approximately 2.6 additional square miles
of the contaminant plume and remove approximately 2000 gallons of TCE from the aquifer over
a 20 year period. (Gallons of TCE removed is supplied fOF comparison purposes. Other VOCs
would also be removed.) The capture zone (see Figure 5) will be achieved within one year of
system start-up.
Capital costs for this alternative are estimated to be $9,160,000 and annual operation and
maintenance costs are $1,770,000. The present value is calculated to be $31,000,000.
Alternative 64C - Extraction near 1-10. Treatment for VOCs. and Discharee to the Grand
Canal
Alternative 64C was developed in the SuppJement to Interim Remedy Feasibility Study report
to present another beneficial end-use for this extraction location. This alternative is similar to
Alternative MR, however treated water would be piped to the Grand Canal for irrigation use.
Extraction wells would be located near Interstate 10. The extracted water would be treated for
VOCs to meet drinking water standards. Inorganics in this extraction area do not occur at levels
that would require treatment before the beneficial use.
The extraction and treatment system would contain approximately 2.6 additional square miles
of the contaminant plume and remove approximately 2250 gallons of TCE from the aquifer over
a 20 year period. (Gallons of TCE removed is supplied for comparison purposes. Other V'OCs
would also be removed.) The capture zone (see Figure 5) will be achieved within one year of
system start-up. As is the case with Alternative lIC, discharge to the Grand Canal will be
interrupted for approximately one month every year. Similar alternatives exist to allow
continued operation of the extraction system, although the additional costs of sUch discharge
alternatives are not included in the cost figures below.
Capital costs for this alternative are estimated. to be $7,390,000 and annual operation and
maintenance costs are $1,640,000. The present value is calculated to be $28,000,000.
22
-------
8.
Summary of Comparative Analysis of Alternatives
ADEQ and EP A analyzed and compared the remedial alternatives developed in the Interim
Remedy Feasibility Study and IRFS supplement based on the nine criteria in the National
Contingency Plan. This section presents a summary of that comparative analysis of alternatives.
The discussion below is summarized in Table 4.
Overall Protection of Human Health and the Environment
Overall protection of human health and the environment addresses whether a remedy provides
adequate protection and describes how risks posed through each pathway are eliminated, reduced
or controlled through treatment, engineering controls or institutional controls. Overall protection
of !tuman health and the environment and compliance with ARARs, which is addressed below,
are the two "threshold criteria" that must be met for an alternative to be deemed acceptable.
All of the alternatives, except No Action, provide some degree of protection of human health
and the environment without substantial negative impacts. Risk is reduced by removing
contaminants from the environment, and inhibiting their westward migration. Alternatives 64C
and 64R provide the largest area of containment (2.6 square miles of the plume) and also contain
the largest mass of contaminants. Alternative 21 provides the next highest degree of containment
(1.5 square miles), and Alternatives 11 and llC provide the lowest degree of containment (0.7
square miles) relative to the other Alternatives. The difference between reinjection and
discharge to the canal is not significant in terms of protection of human health. Negative
impacts associated with the alternatives include the disruption that would result from installation
of pipelines and other components of the remedy, and the impacts of handling, treating and
disposing of residuals (e.g., air emissions and recovered solvents).
As this is an interim remedy, additional future actions may be required to reduce site-wide risks
to an acceptable level.
The ecological risks from groundwater contamination within OU2 are not expected to be
significant for the reasons stated in Section 6.
Compliance with ARARs
Compliance with Applicable or Relevant and Appropriate Requirements (ARARsl. addresses
whether a remedy will comply with Federal and State environmental laws and regulations that
either apply to or are relevant and appropriate for the action being taken. All of the alternatives
will comply with their respective ARARs. Cleanup .of the aquifer to drinking water standards
is not an ARAR because it is beyond the scope of this interim action for OU2: No ARARs
waivers are expected to be needed.
Long-term Effectiveness and Permanence
Long-term effectiveness and permanence refers to the ability of a remedy to maintain reliable
protection of human health and the environment over time. This criterion includes the
consideration of residual risk and the adequacy and reliability of any controls.
23
-------
TABLE 4. COMPARISON OF ALTERNATIVES
........,U(.......
... ......." .
. .." ...... .
.... ,......... .
....... ".". ......, ...........
",'.n .'''''' ... ".......". .,.....
. ........'...... ,..... "P. .,," .....
. '..n "'''P'''' ""'"'''''' ".."....
. .«.""P"""'"'' d. ... .......
~#1p~farand?U?
.(janat~RelnJeCt:.,..
(Flu()ridCiremo~#)....
Overall Protection
of Human. Health &
Environment
~
ARARs Compliance
Long-tenn
Effectiveness
Reduction of
Toxicity. Mobility
or Volume (TMV)
Through Treabnent
Total capture area:
Initial Rate of
VOC Removal:
Will not
prevent
further
downgradient
and vertical
migration of
contaminated
groundwater
yes
No reduction
Some reduction of
risk by reducing
contaminant mass
through treatment
of extracted water.
Untreated
contaminant mass
downgradient of
the capture lOne is
high relative to
21. 64C or 64R.
yes
Least effective
based on area
contained & VOC
mass removed.
Effectively
destroys VOCs
removed.
Fluoride removed
is disposed in
landfill. Smallest
containment area
and lowest VOC
mass removal.
0.7 sq miles
7.7 Ibs/day
. ... . .
n..... .......
".. .... .....
""'.....::.,.......II.....t..,....)... .....
..".,,,.........
...... . .."............
...., "',,' .
.. . .,", "."""'"
...:~l:J~.~I;~~~!.!!
(to....c8lia. 1\::.:... :....:..t.'::.:....:...'........:,..:,.:
...... ..... .
Some reduction of
risk by reducing
contaminant mass
through treabnent
of extracted water.
Untreated
contaminant mass
downgradient of
the capture lOne is
high relative to
21, 64C or 64R.
yes
Least effective
based on area
contained & VOC
mass removed.
Effectively
destroys VOCs
removed.
Smallest
containment area
and lowest VOC
mass removal.
Intermittent canal
availability.
0.7 sq miles
7.7 Ibs/day
....
i',%l'}\
.....'
'" '"
...... ",.... ....... .... .
.... ..... ...,.". ..........
''',.' ........ """'..........
. . . . . . . . . . .. . . . .. ""'" . .. .
.Ptlffip'~fB&tfb~~(
...J.1iglj~~~!#Je#.'
.... .
. ...
.... .
Some reduction of
risk by reducing
contaminant mass
through treatment
of extracted water.
Untreated
contaminant mass
down gradient of
the capture zone is
higher than with
64C or 64R.
yes
More effective
based on area
contained & VOC
mass removed.
Effectively
destroys VOCs
removed. Larger
containment area
than II/IIC and
higher VOC mass
removal.
1.5 sq miles
10.4 Ibs/day
..."
".. .
Ht;4CHH
~~~I~t~idi~i::!
4is~~Iitg~t~\. .........:...:./
dr8ridGanal . .......
Some reduction of
risk by reducing
contaminant mass
through treabnent
of extracted water.
Untreated
contaminant mass
downgradient of
the capture zone is
low relative to
11, IIC or 21.
yes
Most effective
based on area
contained & VOC
mass removed.
Effectively
destroys VOCs
removed. Largest
containment area
and highest VOC
mass removal.
Intennittent canal
availability.
2.6 sq miles
25.9 Ibs/day
. ...... .
.. .... ....
. . .. "''''
... "~~fj~~~~~(64R{;/
..... ..'" :,;::::;:::::;::':::::;.:>
l~1.jlj;~~i
... ""
. .
.. .
Some reduction of
risk by reducing
contaminant mass
through treabnent
of extracted water.
Untreated
contaminant mass
downgradient of
the capture lOne is
low relative to
II, IIC or 21.
yes
Most effective
based on area
contained & VOC
mass removed.
Effectively
destroys VOCs
removed. Largest
containment area
and highest VOC
mass removal.
2.6 sq miles
25.9 Ibs/day
-------
Short-term
Effectiveness
t-.)
v.
Implement ability
Cost (in SooO):
Capital :
O&M:
Present Value:
o
oi...
SO,
. ...... ....., ...' .
::!:!':!:I:I::!::I::'!:j:!I:::i::!:!I~;~:ilijl:I:!!I:,1I"j":I'I!:::::!'
,~$p,'a.(~f.tti4::i,:}...,
i~anal8t~ehijecl/"
"}~..,£': " "'"
..".. ."......
.... .... .. ........, .
'. . ,',',',',",",','''.','.",",','','
:~~p~9f.ffi~::,::;t
.!m~~:i:-~0;~~::
... . .". ...
",:,:!':,::,:.:!'.,II:!::!I::lil;~~::,:i'.:.:::'::I':i,j!l:i,:!!!':'
'...~::m1~~1~:;:i'.,:,:,!::.
,dranif~l1itil.i :'n:::',"
"" .
. . . .. . .......
:::::"::'::':'::::~!}::i::""':'..::, ,
, ,"...... .......... ".......
. .."'" . ... . . . , . . .. ... .' . . . . . .
... ...........", ........... ..........
,ptifuP"'~,B~~:'::
Jligb :&I$~i~Je~::,:
.. ."'" . ...' .
'.':';""';':-;";'.';';:'.'.':",'::','.'::""'.":.'.
",:,: :::::::::::::i!4" '6":',,: :',:,':':,",:',:',':,"':,'
..... :.::=:::\~//:~: ~::ftt. '-:::':".'
'.-:"'..,.,..'.;.;.:.:.;...;'.""'."'" "..' ...:.;,'.;.'
~J~ti~~~i~
" ,
""""'"
'"
....
..... .
Capture zone Capture zone Capture zone Capture zone
established within established within established within established within
one year of one year of one year of one year of
startup. Potential startup. Potential startup. Potential startup. Potential
VOC air VOC air VOC air VOC air emissions
emissions of 0.9 emissions of 1.2 emissions of 2.9 of 2.9 Ibslday.
Ibslday. No Ibslday. Moderate Ibslday. Minimal Highest level of
traffic disruptions traffic disruptions traffic disruptions traffic disruptions
during during during during
Construction. Low construction. construction. Low construction. Low
potential for Lowest potential potential for potential for
worker exposure worker exposure worker exposure worker exposure
to treatment to treatment to treatment to treatment
chemicals. chemicals. chemicals. chemicals.
Technical Technical Technical Technical
feasibility is high. feasibility is feasibility is feasibility is
Administrative moderate due to moderately high moderately high
feasibility is uncertainties based on the based on the
highest based on regarding impact extent of hydro- extent of hydro-
number of wells of bedrock high geologic geologic
and length of on extraction. characterization. characterization.
pipelines. Administrative Administrative Administrative
feasibility i~ feasibility is high feasibility is
moderately high based on number moderate based on
based on number of wells and number of wells
of wells and length of and length of
length of pipelines. pipelines.
pipelines.
3,780
1,260
S19,000
7,000
1,160
$21,000
7,390
1,640
$28,000
9,160
1,770
$31,000
-------
State Acceptance
,Community
Acceptance
No support
N
0\
. .... ,".
.... ... "'..... ..."
",..,::::,:!~:,,;:..:::::::::,,:::::::
i~fu~::~::~:~~':::'::':,:i
I;~~~~~~~~~~:
Several
commentors
preferred this
alternative.
Others supported
this alternative in
combination with
64R.
. . ..
..., .... ...
. . . .. """" ..
'd""""'" ...
..:::........ (~!lQ?:~~j;~~~;::::.:-:... .
.. . .. . . . .. .
.... ......'
. .. . , . .. . .... . ........
. ... ........ '" "."...
..... ............... ....." '"
:purrip:1tt9~~':':,'::.::
::..~~~...~!~~!).
One commentor
noted that
discharges to the
canal would not
be possible year-
round.
.. .. . .
'.",".'.", ,'.. ,","."...'
"",' ," "",,~t.:,:::::=::,,:"'"
. ,." ,.....
".' ,.."..... ..""""
. ..." .... ......" -.........
,",..,.. . ..... ......... ... .......
,." ...."....".....,," ......, ........
..... ....-,-,''''', ............ .....
/l8iilipJd:»~~
H:~gb~}~e~rije~({
No commentors
supported this
alternative.
.. ... . .
,",".',","',".'.'..,',',',',',,','.",',',".'.".'.',' ",".",,",',',".'.',,','..'.",'.'..'.'.' .
:",:,..:,."::"'dPu:,i,..,'t.:'..','s.:.'.:,m.".~,..:..,!.'.!,h~,!p!,i:,!::,:..:I::!,n:,!:...i,':.,::e'.:.'.e;.4,..,ar,;:,.:,..,.::':O,.;,,"t;,.:...0.,.',::.,.,1,1:,::,':,1:::,:::,-,I:,.::I:::.,1::,.,:i:.::I:,.::,':.:,.':.::::,1::,0:,'::,::,:::I:,',.!::,.:::.::,::,.:.::,:,I:::~:i.I,::I,.,:::,;:!:,.:,i:!,::,i,',I:,.:,.,:.:. 0;;;'~"'~~~\!.\
..-. m.... !,t~;li;~:r:\
...GriffidC.~al\ ......... .... .'.:.:.:'
ADEQ prefers this
alternative.
One comment or
preferred this
alternative over
64R. One
comment or noted
that discharges to
the canal would
not be possible
year-round.
Several
com mentors
opposed this
extraction location
due to potential
adverse impacts
on other sources
of contamination
and incomplete
hydrogeologic.
characterization of
the entire capture
zone.
Several
com men tors
opposed this
extraction location
due to potential
adverse impacts
on other sources
of contamination
and incomplete
hydrogeologic
characterization of
the entire capture
zone.
-------
As this is an interim remedy, long-term effectiveness is not a critical factor; however, this
interim action, in conjunction with other actions, will contribute to long-term effective control
of groundwater contamination. "Each of the alternatives should be effective in capturing
contaminated groundwater with its containment area. The magnitude of risk remaining is a
function of the extent of contamination within OU2 that is not captured by a given alternative.
Thus, for example, because Alternatives 64C and 64R have the largest capture zone, these
alternatives would minimize the magnitude of remaining risk. A fmal remedy for the site is
expected to be identified within five years of this Record of Decision.
Reduction of Toxicitv. Mobility or Volume Throueh Treatment
Reduction of toxicity, mobility or volume refers to the preference for a remedy that uses
treatment to reduce health hazards, contaminant migration, or the quantity of contaminants at
the site.
AU of the alternatives, except No Action, use permanent destruction as the primary element to
address the principaJ threat of contaminatio~. Groundwater treatment alternatives include
activated alumina adsorption for inorganics and either air stripping or advanced oxidation for
VOCs. Advanced oxidation would destroy VOCs at the treatment plant, while off-site
incineration of captured VOCs would be used in conjunction with air stripping. Inorganics
(primarily fluoride) removed in Alternative 11 would be precipitated in the form of calcium
fluoride and disposed of in a landfill, thereby reducing the volume of fluoride-contaminated
media and its mobility, although the fluoride itself would not be destroyed.
The alternatives djffer substantially in terms of the VOC contaminant mass contained within their
capture zones and in the initial rate of VOC removal. Alternatives 64C and 64R have the largest
containment areas and the highest rates of VOC removal (approximately 26 lbs/day), while
Alternatives 11 and llC have the smallest containment areas and lowest VOC removal rates
(approximately SIbs/day). Alternative 21 was estimated to have a containment area about twice
the size of Alternatives 11 and 11C but a VOC removal rate (10.4lbs/day) that was only 25%
higher than 11 or llC. Estimates of TCE removed, as listed in the IRFS, for alternatives
including reinjection of treated water (Alternatives 11 and 64R) are slightly lower than estimates
for their counterparts including discharge of treated water to the Grand Canal (Alternatives 11 C
and 64C) due to the effects of injecting water treated for VOCs upgradient of the extraction
wells.
Short-term Effectiveness
Short-term effectiveness refers to the period of time needed to complete the remedy and any
adverse impacts on"human health and the environment that may be posed during the construction
and implementation of the remedy. The following were used to evaluate the short-term
effectiveness of each alternative: protection of the community and workers during remedial
actions; environmental impacts from implementation of alternatives; and the length of time until
remedial objectives are met.
In this interim remedy, additional capture of contaminated groundwater is a primary objective.
27
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All of the alternatives, except No Action, would achieve this objective within one year of system
startup, although the plume area and contaminant mass captured varies significantly among
alternatives. For each alternative, the treatment plant would have air emission controls to reduce
VOC emissions below the allowable maximum (unless advanced oxidation is used, in which case
emission controls are not needed). These controlled air emissions would range from
approximately 0.9 lbs/day for alternatives 11 and llC to 2.9 lbs/day for alternatives 64C and
64R.
Soil contamination is not expected where construction would occur for any of the alternatives,
however safety risks associated with construction activities would temporarily affect the
community. The degree of this safety risk varies with the quantity and type of facilities required
by each alternative. Traffic disruptions would be caused during well and pipeline installation.
Alternative 11 C would cause no traffic disruption. Alternative 64C would require 5 street
cros'sings and 14,650 feet of piping in rights-of-way. Alternatives 21 and 11 are similar in
requiring 8 street crossings each and 22,900 and 29,400 feet of piping, respectively, in rights-of-
way. The most disruptive alternative is 64R, with 19 street crossings and 24,500 feet of piping
in rights-of-way.
Under Alternative 21, workers operating and maintaining remedial facilities would have the least
potential exposure to recovered solvents and treatment chemicals. Alternative llC would cause
the next least potential exposure. Alternatives 64R and 64C would have similar potential for
exposure after Alternative llC, and Alternative 11 would have the most potential. Treatment
chemicals include acids and caustics, biocide, and lime.
Implementability
Implementability refers to the technical and administrative feasibility of a remedy, including the
availability of materials and services needed to implement the selected remedy. It also includes
coordination of Federal, State and local governments to clean-up the site.
Factors evaluated to determine technical feasibility include unknowns associated with
construction and operation of a technology, reliability, level of hydrogeologic characterization,
and ease of supplementing the remedy, if necessary. All of the technologies incorporated in the
alternatives are reliable and effective for treating the target contaminants. Hydrogeologic
characterization is highest in the area of Alternatives 11 and l1C, where the density of data is
higher. Hydrogeologic data density is lower in the area of Alternatives 64C and 64R. ~e
incomplete characterization of the bedrock high results in a limited understanding of
hydrogeology in the area of Alternative 21. The reliability of Alternatives 64C and 64R is less
certain than 11 and 11 C because of the potential for uncharacterized/unknown sources to
contribute contaminants that are incompatible with the treatment system. Each alternative would
allow additional remedial actions to be taken, except that enhancements to reinjection (such as
stimulation of in situ bioremediation of groundwater) are not readily implementable in
Alternatives liC and 64C, which do not include reinjection wells.
Administrative feasibility is a function of the need to coordinate with other agencies and of the
amount of facilities required by each alternative that will be subject to approvals and permitting
. requirements. For this interim action, the most significant factors are the lengths of pipeline and
28
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1- -'
number of wells to be installed. On this basis, Alternative 11 C would have the highest ranking
for administrative feasibility, 64C would rank second, and the remaining alternatives would all
rank significantly lower.
Cost
This criterion examines the estimated costs for each remedial alternative. For comparison,
capital costs, operation and maintenance (O&M) costs, and the present value of capital and
O&M costs are used to compare each alternative. In the Interim Remedy Feasibility Study,
present values were calculated using a 5 % discount rate and 20 years of operation. The
assumption of a 20-year project life reflects EP A Superfund guidance; it does not reflect any
specific rmding regarding the duration of the interim remedy.
The cost of each alternative is shown in the table beneath Figure S. On the basis of present
value, Alternative lIC has the lowest cost ($19,000,000), followed in order by 21, 64C, 64R
and 11. The substantially higher costs for Alternative 11 ($40,000,000) are primarily due to the
capital and O&M costs of fluoride removal.
State Acceptance
State acceptance indicates whether, based on its review of the Remedial Investigation, Feasibility
Study, and Proposed Plan, the state in which the site resides agrees with the preferred
alternative. ADEQ is the lead agency for this site and has prepared this Record of Decision.
Acceptance of this decision by the support agency, EPA, is indicated by EPA's concurrence and
signature in Section I, Declarations.
Communitv Acceptance
Community acceptance is reflected in the community's support for, reservations about, or
opposition to the various components of the alternatives. Fifteen individuals and organizations
submitted comments on the Interim Remedy Feasibility Study, the IRFS Supplement, and the
Proposed Plan for Operable Unit Two. These comments, and Al;>EQ's responses, are presented
in the Responsiveness Summary (Appendix B of this Record of Decision). Comments from
individuals, a citizens' group and organizations (including Potentially Responsible Parties, or
PRPs) supported the idea of additional plume containment. Both the community and the PRPs
(except one) felt that the proposed location for groundwater extraction was questio~ble due to
incomplete hydrogeologic characterization and unclear effects of pumping on other sources of
contamination. One PRP concurred with the selection of extraction near Interstate 10, but
preferred Alternative 64C over 64R. The Gateway Neighborhood Coalition and other potentially
responsible parties preferred groundwater extraction locations associated with Alternative II,
where they believe better hydrogeologic characterization exists, and where no other identified
sources of contamination exist. One PRP recommended a combination of the. proposed
Alternative 64R and Alternative 11.
29
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9.
Selected Remedy
Based on consideration of the comparative analysis of alternatives and the requirements of the
NCP, ADEQ and EP A have selected Alternative 64R as the interim remedial action for Operable
Unit Two at the Motorola 52nd Street site. The remedial objectives of this interim action are
to establish a capture zone across the entire width and depth of the contaminant plume, and to
reduce concentrations of contaminated groundwater within the alluvial aquifer upgradient of the
extraction wells. An additional objective of this remedy is to collect and analyze groundwater
quality, groundwater flow, and other hydrogeologic data during implementation and operation
of the remedy to support the selection of additional remedial actions for the site.
The elements of the selected remedy include:
. Installation of extraction wells near Interstate 10 and Van Buren Street. The extraction
wells will pump water from the alluvial aquifer at an estimated rate of 4,000 gallons per
minute. The actual location, number of wells and pumping rate, to be determined during
remedial design, will be based on the objective of capturing the entire north-south width
and depth of the contaminant plume exceeding MCLs for TCE.
. Contaminated groundwater withdrawn from the extraction wells will be treated to
remove, as necessary, contaminants listed in Table 1. Treatment of contaminated
groundwater will be conducted in a treatment facility located near the extraction wells
using air stripping with off-gas treatment by synthetic resin adsorption. Recovered
solvents. will be transported to an approved facility for destruction. If design
considerations indicate that the advanced oxidation treatment process would be effective
and economical, ADEQ will consider approving the use of this technology in lieu of air
stripping.
. Treated water will be piped to injection wells for injection back into the aquifer. The
. injection wells will be located in a manner to facilitate hydraulic containment of the
contaminant plume and to provide the option of enhancing in-plume remediation.
. The remedy shall include the installation and sampling of groundwater monitoring wells,
the sampling of existing monitoring wells, measurement of water levels at monitoring,
extraction and injection wells, and the measurement of other aquifer properties in order
to:
1) evaluate the effectiveness of the remedy in meeting the remedial objectives.
2) verify or revise contaminant influent concentration estimates that Will be used in
the design of the OU treatment facilities.
3) provide an early warning network so that changes in the groundwater flow regime
or contaminant concentrations that may require modifications in extraction rates,
well locations or treatment methods are identified in time to institute the
necessary facility and operational changes.
30
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4) help determine the need for implementing additional remedial actions in Operable
Unit Two and the nature of the fmal remedy.
Groundwater monitoring shall begin during the time of remedial design to provide data necessary
to complete the fmal design and to establish pre-implementation conditions.
Containment of the plume at this location will be achieved within one year of system start-up.
This interim remedy will continue to operate and will be combined with additional remedies
leading to the fmal remedy for the site.
Locating the extraction wells near Interstate 10 captures a significantly larger area of the
contaminant plume, and also contaminant mass, than would be achieved by locating them at the
Grand Canal. Containment of this larger mass of contaminants is more protective of human
health since it will reduce the future adverse impacts Qn downgradient water users and
uncontaminated areas of the alluvial aquifer. 'Extraction in this location also captures
contaminants from other known and unknown sources. The fact that inorganic contaminants are
not addressed by Alternadve 64R is not seen as a significant drawback, since removal of
inorganic contaminants under Alternative 11 would be done solely because fluoride levels near
the Grand Canal are high enough to require treatment in order to meet reinjection requirements
(i.e., it would not produce any significant benefits to residents in this area of the site since the
groundwater is not used as a source of domestic drinking water supply and fluorides in
groundwater do not otherwise pose a health risk). The uncertainties concerning the nature of
the bedrock high clearly make selection of a remedy at that location inadvisable, but those
uncertainties do not have a significant impact on the effectiveness of Alternative 64R. The
intermittent availability of the Grand Canal to accept treated water makes alternatives with this
component undesirable.
Extraction near Interstate 10 creates a large capture zone that may include plumes from sources
other than Motorola. Based on the available data, which ADEQ believes sufficient for the
purposes of remedy selection, there is no reason to believe that the treatment system cannot be
modified to effectively remove contaminants that would otherwise be incompatible with air
stripping. The groundwater monitoring program which is a part of the remedy will provide the
necessary information to design and implement such modifications if they are needed.
Implementation of Alternative 64R has the potential for significant traffic disruptions during
construction of pipelines and installation of wells: ADEQ will work with affected residents. aI.1d
businesses during remedial design and construction to insure that adverse impacts are reduced
to the extent practicable.
10.
Statutory Determinations
Section 121 of CERCLA establishes several statutory requirements and preferences that address
the selection of a remedial action. When complete, a remedial action must comply with
applicable or relevant and appropriate environmental standards established under Federal and
State environmental laws unless a waiver is justified. The selected remedy must also be
cost-effective and utilize permanent solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable. Finally, the statute includes a
31
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preference for remedies that employ treatment that permanently and significantly reduce the
volume, toxicity, or mobility of hazardous substances as their principal element. The following
subsections discuss how the selected remedy meets these statutory requirements.
Protection of Human Health and the Environment
The Risk Assessment performed by ADHS identified potential exposure pathways at this site.
These pathways include drinking contaminated water from a well tapping into the contaminated
aquifer. By capturing and containing a major portion of the existing contaminant plume, the
selected remedy reduces the potential for degradation of downgradient portions of the aquifer
and thus reduces the risk of exposure of downgradient water users. The selected treatment
technologies for extracted water will provide permanent destruction of VOCs removed during
co~tainment pumping, thereby avoiding any cross-media transfer of VOCs.
Implementation of this remedy will proceed quickly and will not pose any unacceptable
short-term risks to the workers and surrounding community.
Compliance with ARARs
Pursuant to Section 121(d) of CERCLA, the on-site portion of a remedial action selected for a
Superfund site must comply with all Applicable or Relevant and Appropriate Requirements
(ARARs). Any portion of a remedial action which takes place off-site must comply with all
laws legally applicable at the time the off-site activity occurs, both administrative and
substantive. According to the National Oil and Hazardous Substances Pollution Contingency
Plan (NCP) (40 CPR Part 300), "applicable" and "relevant and appropriate II are defmed as
follows:
.
Applicable requirements means those cleanup standards, standards of control, and other
substantive requirements, criteria, or limitations promulgated under federal environmental
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.
.
Relevant and appropriate requirements means those cleanup standards, standards of
control, and other substantive requirements, criteria, or limitations promulg~ted un"der
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 are
more stringent than federal requirements may be relevant and appropriate.
Requirement are also classified as chemical-specific, location-specific, or action-specific.
.
Chemical-specific ARARs are health- or risk-based concentration limits, numerical
values, or methodologies for various environmental media (Le., groundwater, surface
32
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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 ARARs set limits on concentrations of specific hazardous substances,
pollutants, and contaminants in the environment. Examples of this type of ARAR are
ambient water quality criteria and drinking water standards.
.
Location-specific ARARs set restrictions on certain types of activities based on site
characteristics. Federal and State location-specific ARARs are restrictions placed on the
concentration of a contaminant or the activities to be conducted because they are in a
specific location. Examples of special locations possibly' requiring ARARs include flood
plains, wetlands, historic places, and sensitive ecosystems or habitats..
.
Action-specific ARARs are technology- or activity-based requirements which are
triggered by the type of remedial activity. Examples are Resource Conservation and
Recovery Act (RCRA) regulations for waste treatment, storage, and disposal.
Neither CERCLA nor the NCP provide across-the-board standards for determining whether a
particular remedy will result in an adequate c~eanup 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 informatiQn about specific chemicals at the site, specific
features of the site location, and actions that are being considered as remedies.
Table 5 provides an outline of the location- and action-specific ARARs that apply to this site
and to this interim remedy ~ Because the s~lected remedy is an interim remedy, it may not
achieve fma) cleanup levels for the groundw~ter and no chemical-specific ARARs for aquifer
cleanup are int;luded.
The selected remedy will comply with all. applicable or relevant and appropriate requirements.
Since the selected remedial action for Operable Unit Two is an interim action, cleanup
requirements for the aquifer such as attaining MCLs, which would be ARARs for a fmal
remedy, are not ARARs for this remedy. ARARs for the selected remedy are identified in Table
5.
Cost Effectiveness
ADEQ believes that the selected remedy is cost-effective in providing control of the
contaminated groundwater in a reasonable period of time. Section 300.430 of the NCP requires
cost-effectiveness be evaluated by comparing all the alternatives which meet the following
criteria: protection of human health and the environment; long-term effectiveness and
permanence; reduction of toxicity, mobility or volume through treatment; and short-term
effectiveness. While long-term effectiveness will be addressed by the fmal remedy, the selected
interim remedy meets these remaining criteria and provides for overall' effectiveness in
proportion to its cost. The estimated present worth for the selected remedy is $31,000,000.
33
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Table S.
Location- and Action-Specific Applicable, Oi' Reiev2!.ilt md Appropriate
Requirements (ARARs) of federal and state Jaws.
Citation
Endangered Species
16 U.S.C. ~1531 et seq.
Fish and Wildlife
16 U.S.C. ~661 et seq., 40 CFR
~6.302
National Archeological and Historical
Preservation Act, 16 u.s.e. ~469,
36 CFR Part 65, A.R.S ~41-841 -847
and A.R.S. ~41-865
If endangered species are found within or adjacent
to the site, remedial actions shall comply with the
requirements for endangered species in accordance
with the Endangered Species Act.
Remedial actions shall protect the. fish and wildlife
of the area in accordance with 16 use ~661 et
seq.
The laws governing archaeological discovery and
preservation shall be followed if artifacts or
human remains are discovered.
New Well Construction &
Groundwater Use Requirements
Arizona Revised Statutes, Title 45;
45 A.R.S. ~454.01; and ~45-594,
-595 and -596
Section 45-454.01 of the Arizona Groundwater
Management Act (GMA) is relevant and
appropriate to the site... .For activities conducted
onsite, the substantive pOrtions of the provisions
within the GMA are applicable. Remedial actions
undertaken pursuant to CERCLA must meet the
following requirements: a new well is subject to
sections 45-594 (Well construction standards);
45-595 (Well construction requirements; licensing
of well drillers and pump installation contractors);
withdrawn groundwater must be reinjected into the
aquifer or be put to reasonable and beneficial use,
and a person who uses groundwater withdrawn in
an active management area may be subject to the
withdrawal fee and shall use the groundwater only
pursuant to Articles 5-12 of Title 45, Chapter 2;'\ .
and 3.
34
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Table S.
(continued) Location- and Action-Specific Applicable, or Relevant and
Appropriate Requirements (ARARs) of federal and state laws.
Citation Requirement
Arizona Air Pollution Control As a part of the delegated program, the Maricopa
Regulations County Air Pollution Control Regulations adopted
A.R.S. 49-401 et seq. by the Board of Supervisors, October 1, 1990,
Maricopa County Air Pollution Maricopa County Air Quality Standards (Rules
Control Regulations Rules 200, 200, 210,220 and 320) are a part of the State
210,220 and 320 Implementation Plan as dictated by the Clean Air
Act and/or 40 CFR 264, Subparts AA and BB.
The substantive portions of the regulations are
applicable for remediation of groundwater at the
site.
Discharge to Aquifer Portions of the Arizona statutory code for
A.R.S. ~49-241 through 49-244. discharge to an Aquifer, (dermed in A.R.S. 49-
201, 203 and 49-241, et seq) and implementing
regulations (A. A. C. RI8-9-101, et seq.) are
applicable to the Motorola 52nd Street Site. If
Motorola discharges it shall comply with the
substantive requirements for an Aquifer Protection
Permit.
Air stripper Emissions The RCRA requirements apply to air emission
Resource Conservation and standards for process vents and equipment leaks
Recovery Act (RCRA) (40 C.F.R. associated with distillation, solvent extraction or
Part 265, Subpart AA and BB) air stripping operations. The requirements inipact
those operations that manage hazardous waste with
organic concentrations of at least 10 parts per
million. These requirements are applicable.
"Contained in" principle The "contained in" principle provides that any
Arizona Hazardous Waste non-waste material (e.g., groundwater) that
Management Act (AAC RI8-8-261) contains a listed hazardous waste must be
managed as if it were a hazardous waste.
Groundwater extracted as part of this interlm
remedy will contain a listed hazardous waste,
therefore ~ese regulations are applicable to the
management of that groundwater.
35
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Table 5.
(continued) Location- and Action-Specific Applicable, or Relevant and
Appropriate Requirements (ARARs) of federal and state laws.
Citation Requirement
Arizona Hazardous Waste The regeneration or disposal of spent carbon or
Management Act, AAC R18-8-262 other media after use to control emissions of
VOCs must be managed in conformance with the
generator requirements of the state Hazardous
Waste Management Act, including disposal at a
permitted hazardous waste facility.
Arizona Hazardous Waste Groundwater treatment residuals or other media
Management Act Land Disposal contaminated with volatile organic compounds are
Restrictions, AAC R18-8-268 banned from land disposal. Treatment standards
must be met before wastes can be land disposed.
Arizona Hazardous Waste Air stripping towers are miscellaneous RCRA
Management Act, AAC R18-8-264 units, therefore, the substantive requirements of
(40 CFR Subpart X) 40 CFR Subpart X, including any closure and
post-closure care, will be applicable or relevant
and appropriate.
.... .".., .... Oth \:A:tf:H::~ff::'~<. :....:.:.:...t:
... ...,".. / er.:.. c on~specl Icteqwremen s .:..:.
H. "..'..",:.-.' "."' "." ..',:-:..,.". .. ".:."-: " .. '""-.-'-'"'." ," '. . ,"," .":"...".;.;.
Air stripper Emissions The OSWER directive shall be met for control of
EPA OSWER Directive 9355.0-2.8, air emissions from air strippers used at a
June 1989 Superfund site for groundwater treatment.
Controls will be required as part of this interim
remedy on sources with an actual emission rate of
3 lb/hr or 15 lb/day or a potential rate of 10 tons
per year of total VOCs because VOCs are ozone
precursors.
36
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Utilization of Permanent Solutions and Alternative Treatment Technologies or Resource
Recoverv Technologies to the Maximum Extent Practicable
The State of Arizona and EP A have determined that the selected interim remedy represents the
maximum extent to which permanent solutions and treatment technologies can be utilized in a
cost-effective manner for the limited scope of this action. The primary factor in selecting
Alternative 64R for this interim remedy was the rOOuction of toxicity, mobility, or volume of
contaminants through treatment. Alternative 64R captures the largest area of contamination.
The selected remedy also permanently removes and destroys the VOC contamination in the
groundwater, thereby utilizing permanent solutions and treatment technologies to the maximum
extent practicable.
Preference for Treatment as a Principal Element
VOC contaminated groundwater will be extracted, and the VOCs removed by either air stripping
or advanced oxidation. VOC vapors from air stripping will be captured and concentrated
through synthetic resin adsorption for off-site incineration. Therefore; this remedy satisfies the
statutory preference for remedies that employ treatment of the principal threat which per-
manently and significantly reduces toxicity, mobility, or volume of hazardous substances as a
principal element.
11.
Documentation of Significant Changes
The Proposed Plan for Operable Unit Two was released for public comment in January 1994.
The Proposed Plan identified Alternative 64R (extraction near Interstate 10, treatment to remove
VOCs and disposal through injection wells) as the preferred alternative. ADEQ reviewed all
written and oral comments submitted during the public comment period. Upon ~eview of these
comments, it was determined that no significant changes to the remedy, as it was originally
identified in the Proposed Plan, were necessary.
Comments on .the Proposed Plan suggested that Alternative 64C" (with discharge to the Grand
Canal) was preferable to 64R because the costs and traffic disruptions were lower and because
there would be a more immediate beneficial use of the treated water. However, the Salt River
Project, which maintains and operates the canal, noted in their comments that treated water could
not be discharged during the annual month-long maintenance of the canal and that there may be
times when irrigation demands were too low to allow the discharge of 4,000 gpm. Because of
these uncertainties about the continuity of discharge to the canal and the resulting undetermined
impacts on maintaining the capture zone if extraction flows had to be reduced ~r temporarily
stopped, ADEQ did not select 64C. Nonetheless, ADEQ is willing to consider and evaluate,
during remedial design, a treated water disposal option that incorporates both reinjection and
canal discharge if it is economical and does not. reduce the effectiveness of the remedy.
.37
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APPENDIX A.
Administrative Record Index
-------
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
1 07/06/83 1.11.1.05 Map: Irrigation System, Chlorinated Hydrocarbon Analyses (Hubbard)
2 08/19/83 1.1.10.3 Chemical Leak Briermg (ADHS, ADWR)
3 10/04/83 1.1.11.1.03 GCIMS Volatile Organics Analysis
4 11/23/83 1.1.11.1.01 Samp.lAnalysis Data (B. Wiley)
S 12/09/83 1.1.10.4 Rpt: Preliminary Report Chemical Leak Project (Motorola, Inc.)
6 12/15/83 1.1.10.5 Report: Evaluation of Analysis Data (G. Muth)
7 01/04/84 1.1.3.2.39 Comments on Chemical Leak Report of December 9, 1983 (N. Ferrari)
8 01/09/84 1.1.3.2.36 Comments on Preliminary; Report, Chemical Leak Project (H. Seraydarian)
9 01/13/84 1.1.3.2.31 Cover Ltr, for Preliminary Report and Chemical Data/Chemical Data as
Requested for Submittal to State (P. McClellan, P.E.)
10 01/20/84 1.3.08 Preliminary Assessment Region IX with Related Memos Attached (J.
Shepherdson)
11 01/24/84 1.1.4.2.12 Transminal: Request for Phase II Investigation Proposal and Review
Comments (C. Anders) .
12 01/24/84 1.1.5.3.22 Memorandum re: Consolidated ADHS Review Comments: Motorola 12/09/83
Presentation (W. Wiley)
13 02/17/84 8.3.1.07 Comments on Site Materials Submined (Superfund Implem. Gp.)
14 02/17/84 1.1.3.2.25 EPA Comments on Section 7.2 of Preliminary Report w/Copy (8.
Seraydarian)
15 02/27/84 1.1.10.7 Sampling Plan, Motorola, Inc. (J. Rubin)
16 02/21/84 8.3.1.06 Review Comments on Dr. Teitelbaum's Toxicology Report on the .
Groundwater Contamination (E. Theriault, M.p.)
17 02/22/84 Comments on Motorola Sampling Plan (K. Wong)
18 02/23/84 1.3.06 Ltr. re: ADHS Letter to Geno Ori, Motorola, Inc., 2/1/84 (S. Stephens)
19 03/09/84 3.5.2.13 Memo: Task Force Meeting, March 1, 1984, Summary (B. Wiley)
20 03/09/84 Well Sample Analysis Data - TCA (B. Wiley)
A-I
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ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
21 03/06/84 1.3.05 Ltr: Response to Comments on Preliminary Assessment (N. Weiss)
22 03/13/84 Ltr. re: Request for Information, an Extension to May 15, 1984 is Requested
(R. Pettycrew)
23 03/21/84 3.9.1.1.15 Ltr: Response to Comments on Preliminary Report - Chemical Leak Project
(H. Seraydarian)
24 03/26/84 1.1.3.2.14 Ltr: Poor Quality Water Withdrawal Permit Requirements (p. Briggs)
2S 03/29/84 3.5.2.12 r
Summary of Task Force meetmg
26 04/04/84 1.4.01 Site Inspection Report - Motorola 52nd St. Facility (original) w/Copy (U.S.
EPA)
27 04/05/84 1.3.03 Ltr: Comments on Preliminary Assessment (K. O'Regan)
28 04/09/84 1.1.11.2.08 Ltr: Chemical Data from Monitoring Wells(G. Gutierrez)
29 04/10/84 Memo: Laboratory Data Discrepancy (1. Rubin)
30 04/20/84 1.1.1.9 Plan: Sampling Plan REM/FIT Zone II (EPA-9)
31 04/24/84 3.6.4.33 Ltr: Comments on Phase II Work Plan Outline for RIlFS (T. Turner)
32 04/27/84 3.8.2.07 Monthly Progress Report, Apr. 1984 (G. Gutierrez)
33 11 1.1.5.3.01 Exhibit C: hazardous Substance list and Contract Required Detection Limits
34 05/03/84 Response to EPA's Draft Letter (R. Peuycrew, P. Briggs)
35 05/16/84 3.9.1.1.10 Proposed Outline for Revised RIlFS work Plan (5/17/84), Attached. 5/16
Cover Letter. (R. Lee)
36 OS/22184 3.5.2.10 Summary of Working Group Meeting of 5/17/84 (B. Wiley)
37 OS/29/84 1.11.2.04 Analytical Results of Water Samples for EP A Method 502: 1 & 503.1
(Analytical Techn.)
38 06/06/84 3.6.1.27 ADHS, EPA, andADWR Review Comments on 5/17 workplan Submittals
(C. Anders)
39 06/15/84 3.8.2.06 Monthly Progress Report, May 1984 (R. Lee)
A-2
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ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
40 07/02/84 3.6.4.30 Memo: RIIFS Workplan Comments
41 07/09/84 3.8.2.05 Monthly progress report, June 1984 (R. Lee)
42 07/17/84 3.6.1.25 Ltrs: Comments on Phase I and II workplan Draft (C. Anders)
43 07/18/84 RIIFS Workplan Summary of Responses to Comments
44 07/18/84 Memo: Comments on Draft Phase II Workplan (File)
45 07/24/84 Ltr: Transmittal of Chemical QualitylWater Level Data Points (M. Hay)
46 08103/84 3.5.2.06 Ltr: SummaJy of 18 July 1984 technical Committee Meeting (D. Wiley)
47 08/07/84 3.8.2.04 Activities Report, July 1984 (R. ~)
48 09/05/84 3.5.2.05 Summary of Technical Committee Meeting, 8/24/84 (D. Wiley)
49 09/13/84 1.11.2.01 Chemical QualitylWater Level Elevation Data Plots (Gutierrez-Palmenberg)
SO 09/14/84 3.6.3.31 Comments on Draft RIIFS. Workplan and Quality Assurance Project Plan
(H. Seraydarian)
51 09/25/84 3.5.2.04 Summary of Technical Committee Meeting, 9/19/84 (D. Wiley)
52 09/27/84 3.6.1.23 ADHS Comments on Draft RIIFS Work Plan (C. Anders)
53 10/01184 1.1.10.10 Sample Documentation Report. Motorola, Inc. (R. Goloubow, J. Rubin, J.
Surfus)
54 10/17/84 3.6.4.27 Review comments on Quality Assurance Program Plan (T. Turner)
5S 10/22/84 3.5.2.OJ3 Summ.my of 10/10/84 Technical Committee Meeting (B. Wiley)
56 11/14/84 3.8.2.01 Monthly Progress Report; Oct. 1984 (R. Lee)
57 11/27/84 3.5.2.01 Summary of Items Discussed at Technical Committee meeting of 11/14/84
58 11/30/84 3.1.3 Task Specifications - Stratigraphic BoringlWell- RIlFS Motorola (Dames &
Moore)
S9 12/07/84 3.1.4 T.uk Specification; Soil-Gas Sampling RIIFS - Motorola, Inc. (Dames &
Moore)
A-J
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ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
60 12/11/84 11 (M. Rozelle)
61 12/2 1/84 10.2.3.02 Memo: Discussion wlRobert Lee on 12/18/84 and 12/19/84 re: CRP
62 01101/85 10.6.1.17 Newsletter #1 .Update 52nd St. RIIFS. (Motorola, Inc.)
63 01117/85 4.3.2 Groundwater Treatment Plant Bid Package (Attached to 1/17/85 Cover
Letter) (p. Casey, G. Lamb)
64 01/22/85 3.8.3.11 Monthly Progress Report, Nov. 1984 (R. Lee)
65 01/23/85 3.8.3.10 Monthly Progres~ Report; Dec. 1984 (R. Lee)
66 01/23/85 Draft Data management Task specification
67 01/23/85 4.2.2 Bench Scale Treatability Study (Dames & Moore)
68 02/13/85 4.3.1.1 Addendum No.1 to Specification for Fabrication of Pilot Treatment System
for Contaminated Groundwater (p. Casey, L. Foster)
69 02/11/85 3.9.1.2.07 Proposed Soil-Gas Sampling Locations (R. Lee)
70 02/18/85 3.1.7 Draft Sampling and Analysis Task Specification (R. Lee)
71 02/27/85 3.6.1.19 Comments on Draft Specifications for Pilot Treatment Plant (W. Wiley)
72 02/27/85 Work Plan Amendments (L. Foster)
73 02/27/85 3.8.3.08 Monthly Report, Jan. 1985 (R. Lee)
74 03/11185 3.5.3.24 Summary of 2/27/85 Technical Committee Meeting (B. Wiley)
75 03/12185 3.6.3.25 EPA Comments on Draft Task Specification for Sampling & Analysis (A.
Strauss)
76 03/13/85 Comments on Draft Sampling and Analysis Task Specifications (B. Hammett)
77 03/19/85 3.6.1.18 Comments on Draft Task specifications for Water Sampling and Analysis (B.
Wiley)
78 03/21/85 3.5.3.22 Summary of 3/18/85 Meeting (B. Wiley)
79 03/25/85 3.4.55 2 Final Phase I Reports - RIIFS Study Motorola Inc. (Gutierrez-Palmenberg)
A-4
-------
ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
80 04/03/85 3.8.3.07 February Activity Reports of Progress (R. Lee)
81 04/03/85 3.7.16 Draft Responses GW /SW Sampling and Analysis TS
82 04/03/85 3.7.18 (inside package) Responses - Bench Scale Treatability Study
83 04/03/85 3.7.17 Responses - Pilot Plant Specifications
84 04/25/85 3.1.8 Task Specification for Modeling of Groundwater Contamination RIIFS
Motorola Inc. (Dames & Moore)
85 05/03/85 3.5.3.18 Summary of 4/3/85 Technical Subcommittee meeting (B. Hammett).
86 05/13/85 3.8.3.05 April Activity Repons of Progress (G. Gutierrez)
87 OS/24/85 3.1.10 Final Groundwater Level Monitoring Task Specification (R. Lee)
88 06/10/85 Transmittal of Volatile Priority Pollutant Analysis (B. Wiley)
89 06/21/85 3.5.3.15 Agenda: 6/26/85 Technical Subcommittee Mtg. and Summary 5/13/85
Technical Subcommittee Mtg. (B. Hammett)
90 06/26/85 3.8.3.04 May Activity Reports of Progress (R. Lee)
91 07/24/85 3.4.2 Draft Report Stratigraphic Borings Monitoring Wells - RIIFS Motorola 52
Discrete Semiconductor Facility (Dames &. Moore)
92 08/08/85 3.4.3 Draft Report (revision) Soil-Gas Investigation - RIIFS Motorola Inc. (Dames
&. Moore)
93 08/28/85 3.5.3.11 Memo: Technical Subcommittee Meeting Notes (B. Hammett)
94 09/04/85 Ltr: Activity Reports; June & July (R. Lee)
95 09/16/85 3.7.10 Ltr: Responses to Comments on Draft Source Verification Task Specification
Report (R. Lee)
96 09/16/85 3.7.10 Responses to Source Verification Task Specification Comments (8/12/85-
EPA &. 8/23/85 - ADHS) &. Final Source Verification Task Specification (R.
Lee)
97 09/20/85 3.2.13 Ltr: Westbay. Sampling Results. AprillMay 1985 (J. Hussey. E. Ricci)
~8 09/23/85 3.9.1.2.01 Ltr: Pilot Treatment Plant and Welllnstallation (J. Hussey)
A-5
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ADMlNIS1RATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
99 09/26/85 CSMS Waste Oil Storage Tank Monitoring Well (T. Galkowski)
100 09/28/85 3.5.3.11 Memo: Technical Subcommittee Meeting Sept. 1985 RIlFS Press Reports
Aug. 1985 Attached (A. Hammett)
101 10/17/85 3.5.3.09 Memo: Technical Committee Meeting Advisory (B. Hammett)
102 10/18/85 3.6.3.21 Ltr: Comments on Draft Soil Gas Investigation and Stratigraphic
BoringslMonitoring Wells Reports (A. Strauss)
103 10/21/85 3.5.3.08 Minutes of MeetinglTSC Source Verification Planning
104 10/21/85 3.5.3.10 Memo: Technical Sub-Committee Meeting Advisory (B. Hammett)
105 10/22/85 3.5.3.07 Fact Sheet on Water Analysis (Dames & Moore)
106 10/22/85 3.8.3.01 Ltr: RIlFS Progress Report, October 1985 (R. Lee)
107 11/06/85 3.4.4 Draft Well Evaluation Report - RIIFS Motorola 52 (Dames & Moore)
108 11/26/85 3.2.1.3A Results of Private Well Sampling (J. Hussey. E. Ricci)
109 11/27/85 3.4.5 Draft Aquifer-testing: A Preliminary Report - Motorola 52 (Dames & Moore)
110 12/18/85 3.5.3.02 Memo: Technical & Modeling Sub-Committee Meeting Notes (J. Rampe)
111 12/21/85 3.3.1.02 Community Relations Plan-Final RI/FS; Motorola Site (R. Lee)
112 01/20/86 3.4.6 Revised Phase I Report RIlFS - Motorola 52 (Gutierrez-Palmenberg)
113 01/21/86 3.8.4.05 Ltr: Activity Reports of Progress for NovlDec with Reports Attached (2
Copies) (R. Lee)
114 01/22/86 Bench Scale Groundwater Treatability Study (Dames & Moore)
115 03/28/86 3.1.13 Cover Ltr. with -TS for. Additional Borings and Wells: SeCond Phase- (J.
Hussey. S. Smith)
116 03131/86 3.5.4.07 Memo: Highlights of March 21. 1986 Mtg. (J. Rampe)
117 04/01/86 3.4.9 Groundwater Modeling Study for Motorola 52: Summary of Stage I
(Preliminary) Model Investigations (Dames & Moore)
A-6
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ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
118 04/03/86 Subsurface Remedial Investigation Plan No. 38-26-0928-86, ANG, Papago
Military Reservation, Phoenix, Arizona, March 3, April 3, 1986 (U.S. Army
EHS)
119 04/09/86 3.1.14 Cover Ltr. with TS for Courtyard and Wells and Borings (J. Hussey)
120 OS/28/86 3.4.10 Draft Aquifer Testing: Second Report RIfFS - Motorola 52 (Dames &
Moore)
121 06/02/86 3.1.15 (dated 07/02/86) Cover Ltr. w~th TS for Additional Wells: Third Phase
122 06/18/86 4.3.4 Cover Ltr. with PTP Design and Schedule Drawings (J. Hussey)
123 06/24/86 3.4.11 Interim Summary Report (Draft) RIfFS Motorola 52 (Dames & Moore)
124 06/27/86 3.8.4.02 Cover Ltr: with June Activity Reports (R. Lee)
125 07/16/86 3.4.11 (inside package) Ltr. Revisions to Figures 6.5, 6.6, & 6.16, 8lnterim
(SUIDDlaI)' Report (Draft)8 RIfFS 52nd St. Facility for Motorola, Inc. w/copy
126 07/21/86 3.5.4.05 Memo: Highlights of 6/27/86 Meeting (R. Henckel)
127 07/23/86 3.6.3.16 Ltr: Interim SUIDDlaI)' Report Comments (A. Strauss)
128 07/25/86 3.7.06 Ltr. with Responses to ADWR 6/20/86 Comments on Stage I (Preliminary)
Model Investigations Rpt. (J. Hussey)
129 07/28/86 3.6.4.20 Ltr. Review Comments on Draft Interim Summary Report of 6/24/86 (R.
Henckel)
130 07/30/86 3.2.02 Ltr: Proposed Revising, 1986 Ground Water Sampling Plan, New and
Existing wells (J. Hussey, E. Ricci)
131 07/31/86 3.6.1.06 Ltr: Review Comments on Interim Summary Report and TS for Additional
Wells: Third Phase (S. Navarro)
132 07/31/86 3.8.4.01 Ltr: June Activity Reports of Progress (R. Lee)
133 08/01/86 4.2.3 2 Copies Draft Screening Report - Feasibility Study - Motorola 52 R1IFS
(Dames & Moore) .
134 08/13/86 3.4.12 2 Copies Draft Source Verification Report - RI/FS Motorola 52 (Dames &
Moore)
A-7
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ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
135 08/19/86 Ltr: Results of Second Quarter Off-Site Sampling with VOA Analyses of
Water Samples Attached (T. Potucek)
136 08/22/86 3.6.1.05 Ltr: Review Comments on Interim Summary Report of 6/17/86 (T. Potucek)
137 09/04/86 3.6.1.04 Ltr: Review Comments Draft Source Verification Report RIIFS (T. Potucek)
138 09/08/86 3.5.4.03 Memo: Highlights of 8/1186 Mtg. List of Attendees and Proposed Agenda
(R. Henckel)
139 09/10/86 3.7.05 Response to Comments Interim Summary .Rpt. RIIFS (J. Hussey)
140 09/10/86 3.4.11 (inside package) Subminal of Chapter 4 Interim Summary Rpt (Draft) RI/FS
(J. Hussey)
141 09/11/86 3.9.1.3.02 Ltr. re: Leaking Underground Storage Tank investigation at Papago Military
Reservation (T. Potucek)
142 09/16/86 Ltr: Addendum to: TS for Additional Wells: Third Phase (J. Hussey)
143 09/17/86 Ltr: FS Screening Report Comments (A. Strauss)
144 09/22/86 3.6.3.15 Ltr: Review Comments on Draft Source Verification Report (A. Strauss)
145 09125186 3.4.13A Revisions Interim Summary Report (Draft) (G. Miller)
146 10/01/86 4.5.1.07 Ltr: Review Comments on Screening Report Dated August 1986 (T. Potucek)
147 10/29/86 3.5.4.01 Highlights of September 24, 1986 Mtg. (R. Henckel)
148 11/12/86 3.6.3.18 (inside package) Comments on the Draft Physical Chemistry Investigation (A.
Strauss)
149 12/10/86 1.1.4.3.02 Routing and Transmittal Slip; Ltr. re: Direction of the LUST and Motorola
Related Contamination Investigation (T. Potucek)
150 12123/86 3.7.04 RIIFS Work Plan, Responses to Review Comments - Draft.SV Report (G.
Miller)
151 12123/86 3.7.03 RIIFS Work Plan:. Responses to Review Comments - Physical Chemistry
Investigation (Draft)
152 03/20/87 Preliminary Report; Groundwater Contamination Survey No. 38-26-C858-87
A-8
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ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
AZ ANG Papago Military Reservation, Phoenix, AZ (K. Daubel)
153 04/16/87 3.5.5.05 (inside package) Memo: Highlights of February 12; 1987 Meeting (R.
Henckel)
154 05/12/87 3.1.16 Task Specification Long Term Ground-Water Sampling Program for the
Motorola Inc. 52nd St. RIlFS (R. Lee)
155 06/01/87 3.4.15 Attachment B to the Remedial Investigation Report for Motorola Inc. June
1987 (Dames &. Moore)
156 06/01/87 Attachment A Remedial Investigation Report (Draft) June 1987 (Dames &.
Moore)
157 06/01/87 3.4.14 Report Test Remedial Investigation Volume I of IV (Dames &. Moore)
158 06/01/87 3.4.14 Appendices Remedial Investigation Volume III of IV (Dames & Moore)
159 06/01/87 3.4.14 Appendices Remedial Investigation (Draft) Volume IV of IV (Dames &.
Moore)
160 06/01/87 4.2.4 Report Feasibility Study (Draft) (Dames & Moore)
161 06/30/87 Report Test Remedial Investigation (Draft) Volume I of IV wlLtr. re: RI
Report/Superfund Project (Dames &. Moore)
162 07/14/87 ~.2.1.11 Results of the June; 1987 Ground Water Sampling, 52nd St. RIIFS (D.
Hanson)
163 07/23/87 3.5.5.02 (inside package) Memo: re: Highlights of the July 14, 1987 Meeting with
Agenda and List of Attendees (R. Henckel)
164 07/29/87 Motorola 52nd St. Public Health Assessment Cover Letter (K. Takata)
165 08/05/87 Motorola 52nd St. Draft RIlFS Cover Letter (K. Takata)
166 08/20/87 3.6.3.14 EPA's Comments on the Draft FS Report (A. Strauss)
167 08/24/87 4.6.09 Ltr. re: Review Comments, Motorola 52nd St. FS (Draft) Report (June 1987)
(S. Navarro)
168 09/01/87 4.6.08 Risk Characterization Review of the Motorola 52nd St. Feasibility Study (S.
A-9
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ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
Englender, N. Petersen)
169 09/18/87 4.5.1.05 .Comments on Motorola 52nd St. F/S Report (J. Anders)
170 10/06/87 3.6.3.13 Completed Comments on Review of the Remedial- Investigation Report Plus
Major Recommendations (J. Anderson)
171 10/06/87 3.5.5.01 Highlights of the September 9, 1987 TSC meeting (R. Henckel)
172 10/15/87 3.6.4.37 (inside package) ADWR Comments on the Motorola 52nd St. Draft Remedial
Investigation Report (R. Henckel)
173 (none) Computation of Population Served
174 (none) Draft Communication Strategies for Site Proposed to Drop from the NPL (H.
Hadlock, A. Kaswan)
175 05/02/88 8.1.1.02 Health Assessment for Motorola 52nd Street Facility (ATSDR)
176 06/24/88 5.4.1 Draft Remedial Action Plan, Motorola 52nd Street (Dames & Moore)
177 06/26/88 10.1.09 Ltr: Comments on Newsletter #6 (Robert C. Anderson, P.E.)
178 07/03/88 3.9.1.5.03 Ltr: Additional Comments on. Newsletters #1 through #S (Robert C.
Anderson, P.E.)
179 07/11/88 10.4.1.1 Transcript: Motorola 52nd Street Site Remedial Action Plan, Public Hearing
(paul H. Landsman, RPR Court Reporter)
180 07/18/88 10.1.06 Ltr: List of Concerns Regarding Motorola 52nd Street Site (pamela E. swift,
Chairwoman, Toxic Waste Investigative Group, Inc.)
181 07125/88 S.4.1.2A Ltr: re: Proposed Remedial Action Plan (RAP) of Motorola, Inc. (Matthew
R. Berens for Heron, Burchette, Ruckert and Rothwell) Letter Report East
High School Property by Water Resources Associates, Inc., enclosed.
182 07/27/88 10.8 Ltr: re: Motorola S2nd Street Site Remedial Action Plan-A late Comment
(James J. Lemmon, R.G. at the Urban Research Association.)
183 09/12/88 8.2.04 Report: Work Product A-Task Assignment Number 13, Contract Number
2207-OOOOOO-3-3-DR-7084 (Health Risk Assessment by ADHS)
A-I0
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4010.-) Description
184 01/11/88 4.7.03 Responses to RIfFS comments (W. Keilen)
185 09/27/88 5.4.1.1 Lener of Determination - OUI (N. Weiss)
186 09/27/88 5.4.1.1A Responsiveness Summary
187 09/30/88 5.1 Record of Decision - OUI (D. McGovern)
188 01/27/89 3.9.1.6.05 Ltr: Proposal for expanding modeling in Phoenix Active Management Area
(D. Toy)
189 04/14/89 6.3.04 Potential Impact of Motorola Site on East Washington WQARF area (S.
Eberhardt)
190 06/20/89 7.4.6 Consent Order
191 07/24/89 7.4.6.1 Consent Order signature by Superior Coun
192 08/10/89 3.9.1.6.03 Ltr: Statement of Work for Consent Order (R. Lee)
193 08/11/89 7.5.1.01 Statement of Work required by Consent Order (R. Lee)
194 08/25/89 7.9.2.02 Ltr:CommentonStatememofWo~(D.A~~
195 08/27/89 7.5.2.04 Addendum No.1 to Statement of Work (R. Lee)
196 01106/90 3.9.1.7.08 Progress on RI/FS (J. Zelikson)
197 01/09/90 3.2.1.12 Transmittal-Water Quality Data through 6/89 (Dames & Moore)
198 01/22/90 3.2.1.13 Transmittal-geophysical logs, selected aquifer test data (Dames & Moore)
199 01/24/90 3.5.8.08 Meeting minutes
200 03/14/90 3.4.16 Review of Bedrock Issues (Dames & Moore)
201 03/20/90 3.6.2.25 Memo: 90% Design Package - comments (B. Thatcher, Jr.)
.
202 03/22/90 3.6.2.24 Memo: Review of Bedrock Issues - comments (B. Thatcher, Jr.)
203 04/16/90 3.1.19 Draft Task Specification Review of Potential Inorganic Contamination
(Dames & Moore)
204 04/19/90 3.6.2.20 Ltr: Comments on Task Spec Plume Definition (D. Atkinson)
A-ll
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document
Number
Date
ADEQ File #
(4070.-)
Description
205 05/02/90 3.6.2.18 Ltr: EP A comments on Review of Bedrock Issues & Task Spec Plume
Defmition (H. Lauer)
206 05/14/90 3.6.2.16 Ltr: Comment on Draft Soil Vapor Extraction Basis (D. Atkinson)
207 05/14/90 3.6.2.17 Ltr: review of draft Task Spec for Review of Potential Inorganic
Contaminants (D. Atkinson)
208 07/03/90 3.3.3 Final Remedy Workplan Outline & Revised Plume DefInition Program
(Dames & Moore)
209 07/25190 3.6.4.11 Ltr: Comment on Well Abandonment Workplan, Revised Plume Definition
Program (B. Davis)
210 08/02/90 3.6.2.12 Ltr: ADEQ, ADWR, EPA review of Workplan Outline & Revised Plume
Defmition Program (D. Atkinson)
211 08/10/90 8.2 Cancer Incidence & Mortality in East Phoenix (ADHS)
212 10/16/90 4.7.01 Responses to 90% Design comments (J. Seeger)
213 10/18/90 3.6.3.09 Ltr: Comments on Workplan for Final Remedy RIIFS (H. Lauer)
214 10/25/90 3.2.03 Draft Sample Collection & Analysis Plan (Dames & Moore)
215 11/06/90 3.6.2.09 Ltr: ADEQ, ADWR, EPA review of Final Remedy RIIFS Workplan (D.
Atkinson)
216 11/10/90 10.2.1 Community Relations Plan revision (Dames & Moore)
217 11/27/90 3.6.3.06 Ltr: Comments on Sample Collection & Analyis Plan, Quality Assurance
Plan, & Community Relations Plan (M. Montgomery)
218 11/29/90 4.6.01 Ltr: Dept. of Water Resources comments on 90% Design, Health and Safety
Plan, Sampling & Analysis Plan (B. Davis)
219 12/20/90 3.1.20 Task Specification for Courtyard SVE Pilot-program (Dames & Moore)
220 01/04/91 3.4.22 Hydrologic Report in Support of Application for PQGWWP (Dames &
Moore)
221 01/14/91 10.2.3.03 Memo: Comment on Community Relations Plan Revision (B. Mybeck)
222 02/07/91 1.4.07 Memo: Hydrology & CERCLA inspection (S. Calloway)
A-12
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
223 02/15/91 3.2.1.17 November 1990 Water Quality (Dames & Moore)
224 03/01/91 3.9.1.8.24 Ltr: Memos on Central Phoenix Model (F. Putnam)
225 03/27/91 3.3.5 Supplement No.1 Final Remedy RIfFS Workplan Plume Definition (Dames
& Moore)
226 03/28/91 3.6.2.06 Memo: November 1990 Semi-annual Water Quality Report (C. Kafura)
227 04/01/91 3.6.2.05- Memo: November 1990 Semi-annual Water Quality Report & Supplement
No.1 to Final Remedy RI/FS Workplan (C. Kafura)
228 04/04/91 3.5.9.09 Final Remedy RIfFS Meeting notes (Dames & Moore)
229 04/10/91 3.3.6 Supplement No.1 Final Remedy RIfFS Workplan Plume Definition Revision
2. (Dames & Moore)
230 04/19/91 3.2.1.18 Water Quality Data Usability Report, sampling rounds 8-14 (Dames &
Moore)
231 04/19/91 3.1.21 Task Specification for Groundwater Quality Investigation Southwest Parking
Lot (Dames & Moore)
232 04/24/91 3.1.22 Draft Operable Unit Monitor well Task Specification (Dames & Moore)
233 05/15/91 3.9.1.8.20 Ltr: Review of ADWR groundwater model (R. Brown)
234 06/11/91 3.5.9.05 Meeting notes
235 06/17/91 3.1.23 Draft Task Specification for Aquifer Testing (Dames & Moore)
236 06/17/91 3.4.25 Draft Well Installation Report (Dames & Moore)
237 06/24/91 3.6.2.37 Memo: Task Spec for Aquifer Testing (C. Kafura)
238 07/08/91 3.9.1.8.16 Ltr: Draft preliminary Groundwater Quality results plume definintion
program (Dames &. Moore)
239 07/11/91 3.6.2.03 Memo: Draft Preliminary Groundwater Quality Results, Plume DefInition
Program (C. Kafura)
240 09/30/91 3.4.26 Draft Final Remedy Remedial Investigation Report (Dames & Moore)
241 11/22/91 3.6.2.35
Ltr: Draft Final Remedy RI report (D. Atkinson)
A-13
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
242 12/03/91 3.9.1.8.05 Memo: Possible subsidence during pumping (1(. Berry)
243 12/20/91 3.9.1.8.02 Ltr: Contamination in Southwest comer of Motorola Property (R. Johns)
244 01/28/92 3.2.1.26 Operable Unit Baseline Data (Dames &. Moore)
245 02/01/92 3.2.06 Final Sampling Plan-Soil Gas, Soil, &. Ambient Air (Malcolm-PUnie)
246 02/01/92 3.4.28 Final Remedy Remdedial Investigation Report (Dames &. Moore)
247 02/04/92 6.2.01 Dept. of Water Resources. ARARs (1(. Berry)
248 02/04/92 1.2.02 Memo: Groundwater Treatment Plant (L. Hammon)
249 02/07/92 3.2.1.27 Historical Lab Data 1987-1991 (Dames &. Moore)
250 02/18/92 3.2.1.28 Historical Lab Data 8/85 to 12/86 (Dames &. Moore)
251 03/30/92 3.1.18 Draft Task Specification Plume Definition (Dames &. Moore)
252 04/01/92 3.2.0.10 Final Quarterly Groundwater Sampling Plan (Malcolm-Pirnie)
253 04/01/92 3.4.31 Operable Unit Baseline Report (Dames &. Moore)
2S4 04/07/92 3.6.2.3.9 Ltr: Comments on Soil Gas, Soil Sampling and Testing Program (J. Maye)
2S5 04/20/92 1.2.08 Ltr: Response to ADEQ Inspection (G. Fisher)
256 04/27/92 8.1.4.1. Soil Gas Risk Assessment (ADHS)
257 05/06/92 8.6.04 Ltr: Comments on Baseline Risk Assessment (J. Maye)
258 05/14/92 3.4.30 Final Sampling Report Soil Gas, Soil Sampling Program (Malcolm-Pimie)
259 05/18/92 8.6.06 Ltr: Comments on Baseline Risk Assessment (J. Zackrison)
260 05/18/92 3.5.10.06 Technical Committee Meeting Notes (J. Maye)
261 OS/21/92 3.5.10.07 Technical Committee Meeting Notes (J. Maye)
262 OS/29/92 8.6.05 Ltr: Comments on Baseline Risk Assessment (R. Hayslip)
263 06/03/92 3.5.10.08 Technical Committee Meeting Notes (J. Maye)
A-14
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
264 06/05/92 3.6.2.43 Memo: Pre-design RI Workplan (K. Ross)
265 06/08/92 3.4.28.1 Responses to Comments of Final Remedy RI (Dames & Moore)
266 06/08/92 3.7.29 Responses to ADEQ Comments on Final Remedy RI Appendix F. Aquifer
Tests (Dames & Moore)
267 06/22/92 3.6.2.44 Ltr: Review of Final Remedy RI (I. Maye)
268 06/25/92 3.5.10.25 Technical Committee Meeting Notes (I. Maye)
269 06n.9/92 3.6.3.39 Ltr: Comment on Pre-Design RI Workplan (M. Montgomery)
270 07/08/92 3.5.10.22 Citizens Committee Meding notes
271 07/08/92 3.5.10.11 Technical Committee Meeting Notes (I. Maye)
272 07115/92 3.3.8 Pre-design RI Workplan (Dames & Moore)
276 07/20/92 3.9.1.9.47 Ltr: Proposed Ecological Risk Assessment (R. Weaver)
274 C11/23/92 3.5.10.15 Technical Committee Meeting Notes (I. Maye)
275 07/24/92 3.1.24 Task Specification Groundwater Quality Investigation (Dames & Moore)
276 07/31/92 3.4.36 Quarterly Report Groundwater Sampling Round (Dames & Moore)
277 07131/92 3.4.34 Quarterly Report Courtyard SVE Pilot.Program (Dames & Moore)
278 07131/92 3.4.37 Pre-design RI Status (Dames & Moore)
279 07/31/92 3.4.35 Quarterly Report Southwest Parking Lot Investigation of VOC Discharges
(Dames & Moore)
280 08/03/92 3.1.24.1 Revised Task Specification Groundwater Quality Investigation (Dames &
Moore)
281 08/06/92 3.5.10.18 Technical Committee Meeting Notes (I. Maye)
282 08/10/92 3.6.2.46 Ltr: Approval of Pre-Design RI Workplan (I. Maye)
283 08120/92 3.5.10.27 Technical Committee Meeting Notes (I. Maye)
284 08/24/92 3.4.36.1 Memo: Quarterly Report Groundwater Sampling Round (M. Castaneda)
A-IS
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
285 08/25/92 3.5.10.26 Technical Committee Meeting Notes (J. Maye)
286 09/23/92 3.4.43 Draft In-situ Air Sparging/SVE system Field Test SWPL (Dames & Moore)
287 09/25/92 3.5.10.32 Technical Committee Meeting Notes (J. Maye)
288 09/25/92 3.9.1.9.67 Memo: ARARs from Dept. of Water Resources (D. Annis)
289 09/25/92 3.9.1.9.61 Ltr: ARARs from Region IX (M. Montgomery)
290 10/20/92 3.2.1.40 Motorola 52nd StreetlEast Washington Sweep Sample results (M. Castaneda)
291 10/20/92 6.2.04 Potential ARARs (J. Maye)
292 10/30/92 3.4.38 Quarterly Report, October 1992 (Dames & Moore)
293 11/01/92 3.4.40 Baseline Risk Assessment (Arizona Department of Health Services)
294 11/09/92 3.1.25 Pumping Test Task Specifcation (Dames & Moore)
295 11/12/92 3.9.1.9.79 Technical committee meeting notes (J. Maye)
296 11/30/92 3.2.1.37 Motorola 52nd Street/East Washington 1st Sweep sample Groundwater
Elevation Data (M. Castaneda)
297 12/09/92 3.5.10.39 Technical meeting handouts - Proposed final remedy alternatives
298 12/10/92 3.9.1.11.3 AIIiedSignal response to General Notice Letter (p. Li)
299 01/04/93 7.7 lIT Cannon response to General Notice Letter (N. Singh)
300 01/06/93 3.5.11.4 Technical Committee Meeting Notes & handouts
301 01120/93 3.9.1.10.03 Ltr: Comments on draft Ecological Risk Assessment (D. Walker)
302 01/24/93 4.2.6 Tables for Screening Analysis of Alternatives (Dames & Moore)
303 01/26/93 3.5.11.2 Technical Committee Meeting Notes
304 01/27/93 4.2.7 Tables for FS alternatives (Dames & Moore)
305 01/29/93 3.4.41 January 1993 Quarterly Report (Dames & Moore)
306 02101/93 3.2.1.42 Draft Final Report Investigation of Inorganic Contaminants (Dames &
A-16
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA S2ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
Moore)
307 02/04/93 8.1.5 Ltr: Comments on Draft Ecological Risk Assessment (1. Kulon)
308 02/08/93 3.4.23 Bedrock Data Report (Dames & Moore)
309 02/17/93 3.9.1.10.9 Ltr: Tiernay Turbines reponse to General Notice Letter (I. Dubbs)
310 02/19/93 3.9.1.10.4 Ltr: Comments on Screening Analysis of Alternatives (M. Montgomery)
311 02/20/93 3.1.26 Task Spec for in-situ Air Sparging/SVE system field test (Dames & Moore)
312 02/26/93 3.4.41.1 Quarterly Report Supplement (Dames & Moore)
313 03/01193 3.6.2.48 Ltr: Comments on Screening Analysis of Alternatives (1. Kulon)
314 03/02/93 3.5.11.8 Technical Committee Meeting Notes
315 03/22/93 4.5.2 Ltr: Detailed Analysis of Alternatives (1. Kulon)
316 03/23/93 3.5.11.7 Technical Committee Meeting Notes
317 04/01193 8.1.6 Ecological Risk Assessment (SAlC)
318 04/01193 3.2.1.42.1 Summary Report-Review of Investigation of Inorganic Contaminants in
Groundwater (PRC)
319 07/20/93 3.2.1.46 Groundwater Monitoring Plan for 4/93 to 3/94 (Dames & Moore)
320 04/02/93 3.2.0.14 Pilot Scale Test Results UV Oxidation Technology (GPI)
321 04/16/93 3.6.2 Ltr: Comments on Investigation of Inorganic Contaminants in Groundwater
(1. Kulon)
322 04/28/93 3.4.42 Quarterly Report, April 1993 (Dames & Moore)
323 05/01193 3.4.46 Operable Unit Effectiveness Report (Dames & Moore)
324 05/01/93 3.4.45 Southwest Parking Lot RI Report (Dames & Moore)
325 05120/93 3.2.0.15 Southwest Parking Lot Remediation Operation (Dames & Moore)
326 05121/93 3.9.1.10.37 Ltr: request to temporarily stop Operable Unit One (D. Netko)
~27 OS/28/93 3.2.0.13 Draft Detailed Analysis of Alternatives (Dames & Moore)
A-17
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
328 OS/28/93 3.9.1.10.38 Ltr: Modelling meeting on 5/21/93 (Dames & Moore)
329 OS/28/93 3.2.1.47 Revised Technical Memorandum Transport Calibration (Dames & Moore)
330 07/02/93 3.5.11.13 Technical Committee Meeting Notes
331 07/06/93 3.5.11.16 Ltr: Issues from 6/22/93 PRP Coordination Meeting (J. KuJon)
332 07/08/93 3.9.1.10.39 Ltr: Comment on draft Detailed Analysis (M. Montogomery
333 07/20/93 3.2.1.46 Groundwater Monitoring Plan April 1993 to March 1994 (Dames & Moore)
334 07/21/93 3.5.11.13 Technical Committee Meeting Notes & handouts
335 07/30/93 3.4.48 Quarterly Report, July 1993 (Dames & Moore)
336 08/01/93 4.2.8 Draft Interim Remedy Feasiblity Study Report (Dames & Moore)
337 08/03/93 3.3.8.1 Addendum to the Pre-design RI Workplan (Dames & Moore)
338 08/04/93 3.9.3.189 Memo: Comments on Southwest Parking Lot RI Report (K. Ross)
339 08/19/93 3.6.2.51 Ltr: Southwest Parking Lot Remedial Investigation Report (J. KuJon)
340 08/19/93 3.6.2.50 Ltr: Southwest Parking Lot Operations Report (J. KuJon)
341 09/03/93 3.9.1.11.1 Ltr: Interim Adjustment to Integrated Groundwater Treatment Plant (D.
Netko)
342 09/11/93 3.3.9 Workplan Southwest Parking Lot RI (Dames &. Moore)
343 09/16/93 3.9.1.11.2 City of Phoenix Response to General Notice Letter (p. Manion)
344 10/02/93 3.2.1.50 Aquifer Test Report, Well DM-SI8 (Dames & Moore)
345 10/1/93 3.6.2.49 Ltr: Comment on Draft Interim Remedy FS (J. Kulon)
346 10/14/93 3.6.2.52 Ltr: Comments on Operable Unit Effectiveness Repon (J: KuJon)
347 10120/93 3.9.1.10.42 Ltr: Dept. of Water Resources comment on Draft Interim Remedy FS (D.
Annis)
348 10/23/93 3.4.49 Quarterly Report, October 1993 (Dames & Moore)
A-IS
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
349 10/25/93 3.4.50 Motorola 52nd Street Site Review and Update (A TSDR)
350 10/27/93 3.1.28 Task Spec Southwest Parking Lot RI supplemental drilling program (Dames
& Moore)
351 10/29/93 4.2.9 Interim Remedy Feasibility StUdy Report (Dames & Moore)
352 11/05/93 3.5.12.2 Ltr: Summary of 10/14/93 Coordination Meeting (J. Kulon)
353 11/09/93 3.2.1.42.2 Responses to Comments on Investigation of Inorganic Contaminants (Dames
& Moore)
354 11/10/93 3.9.1.10.41 Ltr: City of Phoenix position on accepting treated water (S. Meade)
355 11/24/93 3.5.12.3 Ltr: Summary of 11/15/93 Coordination Meeting (1. Kulon)
356 12/06/93 3.9.3.190 Memo: Review of draft Aquifer Test Well DM-518 (K. Ross)
357 12/10/93 4.2.9.1 Supplement to the Interim Remedy Feasibility StUdy (Dames & Moore)
358 01/01/94 10.2.4 Proposed Community Involvement Plan Revision (ADEQ)
359 01105/94 10.6.3.17 Proposed Plan For the Motorola 52nd Street Superfund Site - Winter 1992
Factsheet (ADEQ)
360 01/11/94 3.6.6.11 Comments on Proposed Plan & Feasibility StUdy (Mr. Barella)
361 01114/94 3.9.1.11.4 Ltt: Operation of OUI after adjustments (J. Sherer)
362 01/21/94 3.5.12.1 Ltt: Summary of 12/8/93 Coordination Meeting (1. Kulon)
363 01/31/94 3.4.51 Quarterly Report. January 1994 (Dames & Moore)
364 02/03/94 3.5.12.4 Transcripts: 213/94 Public Meeting for Proposed Plan (Cahn & Blain)
365 02/18/94 3.2.1.49 Results of Hydrogeologic Investigation of Subsurface Bedrock Conditions
(Errol Montgomery Assoc.)
366 03/03/94 3.6.6.10 Tiemay Turbines Comments on Proposed Plan & Feasibility StUdy (J. Dubbs)
367 03107/94 3.6.5.3 Salt River Project Comments on Proposed Plan & Feasibility StUdy (R.
Hayslip)
368 03/28/94 3.9.3.191 Memo: East Washington Area IsoconcetratioD Contours for the Bedrock
A-19
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SUPPLEMENT #1
ADMINISTRATIVE RECORD INDEX
MOTOROLA 52ND STREET SITE
Document ADEQ File #
Number Date (4070.-) Description
Portion of the Aquifer (K. Ross)
369 04/05/94 3.6.6.9
370 04/06/94 3.6.6.4
371 04/06/94 3.6.6.5
372 04/06/94 3.6.6.6
373 04/06/94 3.6.6.7
374 04/06/94 3.6.6.8
City of Phoenix Comments on Proposed Plan & Feasibility Study (K.
O'Regan)
Gateway Neighbors comment on the Proposed Plan and Feasibility Study (C.
Wheeler, et. al.)
Dames & Moore Comments on Proposed Plan & Feasibility Study (J.
Hussey)
m Cannon Comments on Proposed Plan & Feasibility Study (L. Narducci)
AlliedSignal Comments on Proposed Plan & Feasibility Study (D. Reese)
Motorola Comments on Proposed Plan & FeasibilitY Study (D. Netko)
A-20
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APPENDIX B.
Responsiveness Summary
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MOTOROLA 52ND STREET, PHOENIX, ARIZONA
RESPONSfVENESSS~Y
A.
OVERVIEW
The Arizona Department of Environmental Quality (ADEQ) identified a preferred alternative for
a second interim remedy, Operable Unit Two (OU2) , to provide additional containment of
contaminated groundwater at the Motorola 52nd Street Site. ADEQ's preferred alternative
involved extraction of groundwater in the vicinity of Interstate 10 and Van Buren Street.
Treatment of the extracted water for volatile organic compounds (VOCs) would be accomplished
by either air stripping with synthetic resin filtration of off-gases or advanced oxidation
technology. The treated water would be reinjected into the ground.
Judging from comments received during the public comment period, the community and
Potentially Responsible Parties (PRPs) supported the idea of additional plume containment. Both
the community and the PRPs (except Motorola) felt that the proposed lOCation for groundwater
extraction was questionable due to incomplete hydrogeologic characterization and unclear effects
of pumping on other sources of contaminatipn. Motorola concurred with the selection of
extraction near Interstate 10, but preferred Alternative 64C over 64R. The community and some
PRPs preferred groundwater extraction locations associated with Alternative 11 near the Grand
Canal, where better hydrogeologic characterization exists, and no other identified sources of
contamination exist. AlliedSignal recommended a combination of the preferred alternative and
Alternative 11.
These sections follow:
.
.
Background on Community Involvement
Summary of Comments Received During the Public Comment Period and Agency
Responses
- Part I: Summary and Response to Local Community Concerns
General and procedural comments Interim remedy alternatives
Other known and unknown sources Additional options for alternatives
Public health concerns
- Part ll: Comprehensive Response to Specific Legal and Technical Questions"
Amount and quality of data The FS and comparison of alternatives
Technology concerns National Contingency Plan
The FS model " Applicable or Relevant and. Appropriate
ADEQ contaminant contour maps requirements
Other legal concerns
.
.
Remaining Concerns
Attachments: Community relations activities since December 1991.
Figure - Predicted drawdown for Alternatives 64C/64R
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B.
BACKGROUND ON COMMUNITY INVOLVEMENT
The Motorola 52nd Street site has received a high level of community interest since the
beginning of investigations in 1983. Before the completion of Operable Unit One (OUl),
Motorola had the primary responsibility for community involvement. Newsletters were created
by Motorola in the early stages of the investigation. Due to community concerns about the
reliability of data coming from Motorola, ADEQ assumed the responsibility for community
involvement after OUI.
An attachment shows a list of events ADEQ conducted between late 1991 and Summer 1994,
including fact sheets, open houses, community meetings, citizens committee meetings, and less-
formal events in neighborhood homes. One neighborhood group, the Gateway Neighborhood
Coalition, is the recipient of a Technical Assistance Grant for the site. Through the Gateway
Neighbors, and events in the community, ADEQ has recognized some common concerns about
remedial activities at the site:
1)
Citizens contend that a number of potential contaminant sources are not being factored
into risk calculations and remedial action decisions. These mclude air emissions from
manufacturing processes and VOC vapors in the sewer system.
ADEQ response: ADEQ recognizes the presence of these potential sources, however
air emissions from manufacturing are beyond the scope of CERCLA response authority
for this National Priorities List site. ADEQ has suggested contact with Maricopa County
for these concerns. The County is the primary agency regulating air emissions. Sewer
odors are also beyond the scope of this project, however the City of Phoenix has recently
conducted a number of activities to reduce sewer odors. The City sealed manholes in
the area, and then unsealed them at the request of the community after unsatisfactory
results. The City also installed a type of flapper valve system in the sewers to allow
wastewater to flow, but not allow vapors to back up.
2)
Citizens also contend that specific data from private wells has not been accounted for in
risk calculations.
ADEQ response: The Baseline Risk Assessment prepared by the Arizona Department
of Health Services is designed to estimated current and potential future risks associated
with contaminants at the site. Some private well data were not included since the wells
are not in current use and are not expected to be used in the future. Studies conducted
by the Agency for Toxic Substances and Disease Registry (ATSDR) in 1988 and 1993
were designed to assess cumulative effects of all potential environmental factors in the
community .
B-2
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C.
SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT
PERIOD AND AGENCY RESPONSES
The public comment period for the draft FeasibilitY Study (FS) and the Proposed Plan for
Operable Unit Two at the Motorola 52nd Street site was held from January 5, 1994 to April 6,
1994. Comments received during this time are summarized below. Part I of this section
addresses those community concerns and comments that are non-technical in nature. Responses
to specific legal and technical questions are provided in Part n. Comments in each part are
categorized by relevant topics.
Part I - Summary and Responses to Local Community Concerns
Ge.neral and procedural comments
1)
A citizen at the public meeting asked a general question regarding the need for an
appointment to review ADEQ's files on this project.
ADEQ response: An appointment is preferred. Many people are interested in reviewing
this project's fIles specificaIly. Due to space limitations, ADEQ can only accommodate
a smaIl number of people at one time. Many people request that sections of the fIle be
copied for them, which may require flIes to be sent out to a copy company. An
appointment will ensure that the desired portions of the file are available. Please contact
Julie Jones at (602)207-4190 for an appointment. Be advised that ADEQ charges 25C
per page for copying. Major recent documents for this project can also be found at the
Saguaro Branch Library at 2802 N. 46th Street.
2)
A citizen at the community meeting commented that the community involvement plan did
not adequately describe the number of people that live in the area.
ADEQ response: A primary purpose of the community involvement plan is to identify
community concerns and plan the types of activities that will be necessary to properly
involve the community in the process. In that context, it is important to know that
groups requiring information in languages other than English reside in the. area. The
current Community Involvement Plan specifies that approximately 6,800 monoliriguaI
Spanish speakers live in the area of the NPL site. The Community tnvolvement Plan is
not an attempt to accurately estimate the total number of people residing in the area.
Also, see comment number 4 under the "Public Health Concerns" category.
3)
A citizen at the public meeting had also been.to a meeting for the Motorola 56th Street
site on December 14, 1993. He had concerns that written respons~s that were promised
as a result of that meeting had not yet been provided.
ADEQ response: The written responses were completed and supplied to the Gateway
Neighborhood Coalition on March 25, 1994. A copy of that document is in ADEQ's
B-3
-------
5)
project files and is also placed in the information repository at the Saguaro Branch
. Library .
4)
A citizen at the community meeting expressed concerns regarding the timing of the
meeting. Many people forget if the meeting is held two or three weeks after it is
announced. The' citizen recommended that PRPs put some of their advertising budget
toward additional meeting announcements.
ADEQ response: The time between the announcement of the Proposed Plan and the
actual meeting was intended to allow the community an opportunity to review
information about the site to make informed comments. The Gateway Neighborhood
Coalition is one avenue ADEQ will use to keep the community aware. ADEQ also has
an Automated Information Line that provides information on upcoming meetings and
other items. The phone number is 207-4300. The citizen suggested that additional
notices should be placed by the PRPs. No regulatory requirement exists to force PRPs
to do this, but some may volunteer.
AlliedSignal commented that trichloroethane (TCA) contamination emanating from their
facility exceeds the EP A Maximum Contaminant Level (MCL) only within the
boundaries of their facility.
ADEQ response: Available data support this observation, however it does not take into
account the degradation (or breakdown) that TCA undergoes once it is in the
groundwater. When TCA breaks down in the environment, it becomes 1,1-
dichloroethylene (1,1-DCE). This is especially true in Arizona's alkaline soils. ADEQ's
evaluation of groundwater quality data indicates a plume of 1,1-DCE above the MCL
beginning at the AlliedSignal facility and extending to at least 16th Street. After more
time in the environment, 1, 1-DCE breaks down to become vinyl chloride, a known
human carcinogen. Vinyl chloride has been detected above MCLs in wells at
AlliedSignal.
Other known and unknown sources
1)
The Gateway Neighborhood Coalition (GNC), AlliedSignal (Allied), Tiernay Turbines
(Tiernay), the City of Phoenix (COP), and lIT Cannon (lIT) have expressed .a concern
that the preferred alternative would merge contaminant plumes from other sources and
that there may be unknown chemicals in those plumes which will not be remediated by
the proposed treatment method. This concern was also presented by a citizen at the
public meeting. Motorola commented that technical data do not indicate the presence of
contaminants beyond the abilities of the preferred remedy, and that capture of
contaminants from other upgradient sources is an advantage of the Alternatives MC and
MR.
B-4
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ADEQ response: Through various investigations, ADEQ has identified a number of
potential sources of groundwater contamination at this site. In mapping contamination
across the East Washington Water Quality Assurance Revolving Fund investigation area,
just west of the Motorola plant, ADEQ has detennined that one continuous area of
volatile organic compound (VOC) contamination exists from 52nd Street to 7th Avenue
and beyond. ADEQ considers the sources, known and unknown, to already be merged
since the contamination consistently occurs across the area. Groundwater sampling
during many years of investigations has not identified any contaminants that would be
incompatible with treatment technologies in the preferred interim remedy alternative.
Groundwater monitoring will continue during the remedial design phase of the project
to ensure that incompatible substances are identified. The treatment system will be
modified if necessary .
2)
The COP identified the West Sky Harbor Fuel Remediation site as one effort that may
be impacted by the preferred remedy.
ADEQ response: The potential changes in groun,dwater floW direction and/or velocity
are not expected to have significant adverse effect on remediation of other sources or
plumes, including the Sky Harbor Fuel Remediation site. Groundwater pumping as part
of this interim remedy is expected to increase groundwater flow velocity by 10 to 20
percent within 3000 feet of the extraction wells (see attached figure 1 for impacted
areas). The Sky Harbor Fuel Remediation site is farther than 3000 feet from the
extraction well locations, so the impacts on that particular site would be even less.
ADEQ and EP A will continue to evaluate those issues during design and implementation
of the selected remedy.
3)
The COP, the GNC, and Allied recognized the contamination from the Motorola plant
at 56th Street and Earll as another source potentially impacted by this ~terim remedy.
The GNC and Allied suggest that Alternative 11 would help to control that source as
well.
ADEQ response: Groundwater contamination from the Motorola 56th Street site is a
distinctly separate plume being addressed under Arizona's Water Quality Assurance
Revolving Fund (wQARF) program. At its current rate of movement, and if no action
is taken, the plume from the 56th Street plant would require at least 5 to 6 years b~ore
it would begin to combine with the NPL site plume. If no action were taken 011 the
Motorola 56th Street site plume, Alternative 64R would capture that contamination.
ADEQ expects to identify appropriate remedies for the 56th Street plume within a year.
Potentially including this separate plume in the National Priorities L~ site is not
desirable and may tend to complicate and extend the remediation. .
4)
The GNC and the COP identified potential impacts of the interim remedy on the ability
of the PRPs to adequately complete their respective site characterization work.
B-5
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6)
7)
8)
ADEQ response: Source characterizations are on-going at Tiemay Turbines,
AlliedSignal, and lIT Cannon. After the Record of Decision for OU2 is complete,
several months of formal negotiations will take place to create a consent decree for the
design and construction of OU2. The design stage will take nine months to a year to
complete, and the construction schedule will depend largely on the design. Therefore,
the PRPs will have 18 months, at a minimum, to continue their source characterizatiQn
activities. If that work can be completed with a minimum of obstacles, source
characterization should be complete in that time.
5)
The GNC identified silicon slurry beds on the Motorola plant as a potential source not
accounted for in the FS. A citizen at the public meeting also expressed concern that the
neighbors had not directly been notified of the presence of the silicon slurry beds, and
suggested that a centralized Bulletin Board System would allow access to this type of
information.
ADEQ response: The silicon slurry beds recently went through closure procedures
under ADEQ's Aquifer Protection Permit program. That program has indicated that
clean-closure has been attained, therefore it is unlikely that this area would be a
continuing source of contaminants. The location of the silicon slurry beds is inside the
area captured by OU1, therefore any potential releases from the beds would be captured
by the existing treatment system. The citizen's suggestion during the public meeting that
a centralized bulletin board system be developed is very good and is under consideration
by ADEQ management.
The GNC identified sewage ponds at 48th Street south of the Grand Canal as another
potential source of contamination not accounted for in the FS. These ponds reportedly
received wastewater from the Motorola 52nd Street plant.
ADEQ response: Groundwater investigations across the East Washington WQARF area
do not indicate that a source of organic or inorganic contaminants exists in that area.
The City of Phoenix was contacted regarding sewage ponds in the area, and were not
able to conflrnt their existence. The City suggested that the ponds may have been for
stormwater retention and not sewage.
Tbe GNC identified leaking sewers, which carry Motorola industrial wastewater
discharges, as a potential source not accounted for ~ the FS.
ADEQ response: Maintenance of the sewer system and permitting of discharges are
the responsibility of the City of Phoenix. Regular maintenance procedures conducted by
the City include video inspections every four to five years, and these activities have not
caused the City to believe the pipes are leaking.
The COP commented that requirements of the Resource Conservation and Recovery Act
(RCRA) Subtitle C were not identified as ARARs, and that commingling of plumes could
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trigger costly RCRA requirements that would not otherwise be ARARs.
ADEQ response: Existing data suggest that plumes from several sources have already
become commingled; regardless, the selected remedial activity involves pumping and
treating groundwater containing several VOCs, including TCE (a listed waste in this
case). Therefore, RCRA Subtitle C storage/treatment requirements are ARARs for
groundwater storage/treatment. Once the groundwater is treated to a health-based
standard, it is considered to no longer contain hazardous waste and no longer is subject
to RCRA requirements.
Public health concerns
1)
The COP found no correlation between the Baseline Risk Assessment and this interim
remedy. Also, the COP recommends that the risk assessment be expanded to cover the
entire site.
ADEQ response: The Arizona Department of Health Services (ADHS) completed the
Baseline Risk Assessment in November 1992 to cover the area that was being considered
for a fInal remedy at that time. That area is shown in Figure 4 of the Record of.
Decision. ADEQ agrees with the COP that the risk assessment needs to be expanded and
will work with ADHS as new data is collected. While the entire contaminated area is
not included in the Risk Assessment, all of the potential exposure scenarios are
addressed. This interim remedy is not intended to meet all health-based and regulatory
goals, but to reduce the spread of contamination until a remedy that can meet those goals
is defmed. EP A guidance does not require the Risk Assessment to be complete before
interim action is taken. .
2)
The COP and Tiernay expressed a concern that the FS did not consider that
implementing an interim remedy would expose the community to contamination (via air
emissions from air strippers) that they are not currently exposed to.
ADEQ response: The FS did determine that untreated air stripper emissions would
violate federal or county standards. Treatment of air stripper emissions 'has been
i,ncluded as part of the remedy to reduce those emissions to levels permissible by
Maricopa County'. Quantitatively modeling and determining exposure and risk from
emission of 3 pounds per day (the level beyond which treatment to reduce emissions is
required) is not practical, but the health risks from such a small emission would certainly
be less than would be required to produce adverse health effects. For comparison,
according to the Maricopa County Bureau of Air Pollution Control, the. average dry
Cleaner in Maricopa County emits (under permit) approximately 4.5 pounds per day of
tetrachloroethylene, or PCE. This amount also would be less than required to produce
adverse healtb effects.
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4)
S)
6)
3)
The GNC commented that public health concerns, in terms of inorganic contaminants,
were not given sufficient weight in selecting alternatives. Potential impacts of leaving
inorganic contamination in place needs to be considered.
ADEQ response: Inorganic contaminants are not treated by the preferred interim
remedy. Since there is no current exposure to groundwater contaminants, leaving
inorganic contaminants in place until a final remedy is identified does not increase
current or potential exposure risks. This interim remedy will not adversely impact the
ability to remove the inorganic contaminants in the future.
The GNC commented that the potentially impacted population was not adequately
characterized in the FS, in terms of numbers of people, houses, schools, etc., and
therefore evaluating effectiveness of alternatives is not possible. This concern was also
expressed by a citizen at the public meeting.
ADEQ response: The Baseline Risk Assessment estimated potentially exposed
populations using census track information. Risk is evaluated in terms of increased risk
to individuals, not the total number of people at risk. Similarly, remedial alternatives
are evaluated based on effectiveness in addressing potential exposure to contamination,
not on the basis of total number of people potentially exposed. Estimates of potentially
exposed populations were made in the early stages of the Superfund process. The
Preliminary Assessment and Site Investigation phases assessed potentially exposed
populations in order to determine whether the site was eligible to become a National
Priorities List site. These documents are part of the Administrative Record on which
this interim remedy decision was based.
A citizen at the public meeting also asked how the proposed containment plan protects
people from risk during construction.
ADEQ response: Risks during construction of the interim remedy~are limited to those
associated with construction activities. Exposure to groundwater contaminants is unlikely
unless direct exposure to groundwater during the drilling of necessary wells occurs.
Standard safety procedures will be employed during construction activities to limit public
access to areas where exposure might occur.
A citizen at the public meeting stated that he had been exposed to CODtaminants from"the
Motorola plant in the past and had concerns that his mental health had been impacted,
and that friends of his were now either dead or in prison due to mental health problems.
ADEQ response: ADEQ consulted the Arizona Department of Health Services regarding
this concern. Studies of workers occupationally exposed to high levels of TCE for long
periods have not found a relationship between exposure to TCE and mental illness.
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2)
7)
A citizen commented that other visible signs of water. soil, and air contamination exist.
such as lack of birds and insects. and deformities in cats and dogs.
ADEQ response: ADEQ has no data that would link these conditions to the Motorola
S2nd Street Superfund site. An ecological risk assessment for the site was completed in
April 1993. which concluded that no threatened or endangered species occur in the area.
The assessment concluded that there is little concern regarding exposure of ecological
receptors, with the exception of levels of arsenic and lead above aquatic freshwater
criteria in SRP inigation well 18E-SN (which feeds the Grand Canal). SRP currently
uses water from Arizona.s reservoir system to supply inigation water.
Interim Remedy Alternatives
1)
The COP and the GNC commented that Alternative 11 is the only alternative to treat
inorganic contaminants, and have concerns that the preferred alternative doesn.t. A
citizen at the public meeting asked "How does proposed Alternative No. 64 contain
inorganics such as fluoride betWeen 46th Street and the bedrock high area?" Motorola
commented that treatment for inorganics is not the main purpose of this interim remedy.
ADEQ response: The primary goal of this interim remedy is containment or control of
the movement of the VOC contaminant plume. Inorganic treatment is a component of
Alternative 11 because fluoride levels in that area would prohibit reinjecting the water
back into the ground if not treated~ In the area where extraction is located in the
preferred alternative, inorganic contaminants do not occur at levels which would require
treatment before reinjection. The selected remedy will not preclude any future treatment
of inorganics. If inorganics reach the proposed extraction location at concentrations high
enough to require treatment, the treatment system can be modified to remove inorganics.
Alternatively, it would be possible at some future date to install supplemental facilities
for capturing and treating inorganic contaminants at a location closer to the Motorola
plant where such treatment would be more efficient due to higher concentrations.
The COP considers the selection of Alternative 64R a contradiction to remedial action
objectives identified in the FS, specifically the goal of treating extracted water for VOC
and inorganic contaminants. Motorola commented that containment is achieved by
Alternatives 64C and 64R better than the others. that they are more effective at reducing
contaminant concentrations. and provide containment of several identified. uncontrolled
contaminant sources.
ADEQ response: The FS states that the primary goal is to contain the migration of
VQCs. Treatment for inorganics is not a universal goal of this interim remedy.
Removal of contaminants in extracted water will be necessary prior to disposal.
Extraction of groundwater in the area specified for Alternative 64R will attain the goal
of containing the migration of contaminants, and treatment for inorganics will not be
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4)
5)
6)
necessary since inorganics above regulatory standards do not occur in the area.
3)
The COP and Tiemay expressed a concern that it is not known how this interim remedy
will be incorporated with the fInal remedy.
ADEQ response: Containment of contaminants as part of this interim remedy will
inhibit the further movement of contaminants while continuing to characterize the site and
appropriate remedies researched. While it is not possible to know precisely what role
this interim remedy will play in the fmal remedy, ADEQ believes OU2 will be
compatible with the probable fmal remedy options that might be proposed.
The COP and Motorola commented that it is unclear why Alternative 64R with -
reinjection of treated water was selected since Alternative MC, with discharge to
inigation canals, is less expensive and more easily implemented. Motorola contends that
reinjection of the treated water is not crucial to the success of the remedy, and that
discharge to the canals provides a more immediate beneficial use of the treated water.
ADEQ response: Discharge to the Grand Canal is not preferred because access to the
canals may be erratic due to maintenance and irrigation water demand considerations.
Reinjection of the treated water provides a more reliable method of treated water use.
The potential for a combination of these two options will be evaluated during the
remedial design. Also, the potential for bioremediation to assist in actual restoration of
contaminated groundwater is being researched. If bioremediation is determined to be
effective, this could be easily implemented using the injection wells associated with
Alternative MR. Any decision in this regard would not be made until the public has an
opportunity to comment.
The COP expressed a concern regarding the location of injection wells in relation to
remediation efforts at the Sky Harbor Fuel Remediation site. The comment also
requested specific design information.
ADEQ response: The precise location and design of reinjection wells will be determined
during the design of the interim remedy system. It is not anticipated that the interim
remedy will adversely affect the efforts at the fuel remediation site, however such
impacts will be considered and addressed as necessary during remedy design.
The COP and Motorola commented on the amount of public disruptions involved with
the alternatives. The COP feels that not enough study has been done on the feasibility
of 19 street crossings and 24,000 feet of piping under the preferred alternative.
ADEQ response: Detailed design considerations such as these will be addressed during
the design of this interim remedy. ADEQ and EPA do not consider this factor
significant enough to change the selected remedy, however the potential to combine
discharges of treated water to the Grand Canal with reinjection will be examined during
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remedial design to possibly reduce disruptions. Consultation with the communities
potentially impacted by construction will begin early in the design process.
7)
Allied commented that the area influenced by the preferred remedy is so vast that it
cannot accomplish its objectives. .
ADEQ response: Allied presented no technical justification for this opinion. ADEQ is
confident in its understanding of the site conditions and the ability to design a system
capable of accomplishing the objective of containing VOC movement.
8)
The GNC commented that the preferred alternative does nothing to remediate
contamination in bedrock east of the Grand Canal. The GNC prefers Alternative 11
since it captures both bedrock and alluvium contamination in an area historically
described as containing a significant amount o,f contamination.
ADEQ response: The GNC is correct that the preferred alternative will not affect
contamination in bedrock east of the Grand Canal. The final remedy for the site will
necessarily address this concern. Movement of bedrock contamination east of the Grand
Canal during this interim remedy is not expected to preclude its capture as part of the
final remedy. In the comments from the GNC, references were made to reports prepared
by Motorola in 1983 suggesting the area near the Grand Canal contains significant
amounts of contamination. ADEQ considers contamination above EPA Maximum
Contaminant Levels (MCLs) to be significant. Current groundwater quality information
across the Phoenix area suggests levels of VOC contamination exist above MCLs as far
west as 75th Avenue, therefore, the volume of contaminanted groundwater east of the
Grand Canal is significantly greater than the volume of contaminated groundwater
between OUI and the Grand Canal.
9)
The GNC commented that reverse osmosis technology was removed from consideration
for inorganics treatment early in the FS process without detailed explanation.
ADEQ response: The discussion of reverse osmosis occurs in the FS in section 4.5.2.
Activated alumina was selected as the technology for inorganic treatment because it
selectively reduces fluoride and arsenic concentrations. It is also considerably less
expensive than reverse osmosis - .reverse osmosis is estimated to cost $1.37 per 1000
gallons of water treated, while activated alumina would cost $0.38per 1000 galloi!s..
10)
Salt River Project, a water purveyor, commented that discharges to the Grand Canal may
be periodically interrupted due to maintenance, or irrigation demand less than the
capacity of the extraction wells.
ADEQ response: ADEQ is aware of the potential for sporadic interruptions in the
availability of the canals as a discharge option. This is one reason that canal discharges
were not a preferred component of this interim remedy.
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11)
12)
13)
14)
15)
Salt River Project expressed a concern regarding the ability to track the amounts of
treated water discharged into the canals.
ADEQ Response: Based on design considerations, OU2 may include a combination of
reinjection and discharge of treated water to canals. Some manner of flow metering will
be required in the design to track the amounts of water treated. Salt River Project's
concerns could also be addressed by requiring measurement of the amount of water
discharged to the canal system.
Salt River Project disagrees with a statement in the FS that Grand Canal water is
naturally of lower quality.
ADEQ response: ADEQ could not fmd the reference in the FS, but appreciates the
clarification. The statement was not intended to be derogatory.
Salt River Project identified seven irrigation wells that supply water to the Grand Canal
which may be affected by the contamination and the interim remedy.
ADEQ response: Two of the seven wells, well 18E-5N near 40th Street and Van Buren
and well 16.9E-6N near 32nd Street and McDowell, may be affected due to their
proximity to the contaminant plume. When pumping, those wells will need to be
monitored for water quality and potential impacts on plume movement. Coordination
with Salt River Project regarding times and rates of pumping of the irrigation wells will
be important in understanding the effects of this pumping on the contamination and the
interim remedy.
At the public meeting, a citizen commented that some alternatives which treated
inorganics, and included bioremediation, were removed from consideration early in the
process. Specific alternatives identified were alternatives 29, 35, and 62.
ADEQ response: The alternatives identified were researched during the search for a
fInal remedy. When ADEQ and EP A decided that a (mal remedy was not possible at this
time, the list of potential alternatives was reduced to those "final remedy" alternatives
that might make appropriate interim remedies. Alternatives 29,35, and 62 all consisted
of two or more lines of containments wells, one of which is located near the bedrock
ridge. From preliminary cost estimates during initial screening of alternatives, the least
expensive of these alternatives was approximately $50 million. Even if these alternatives
had been carried forward for further consideration, the impacts of the bedrock ridge on
those alternatives would have rendered them ineffective.
A citizen at the public meeting commented on the lack of local reuse options for treated
water. This issue had been identified in 1988 and little appears to have been done to
resolve it. .
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ADEQ response: The Arizona Department of Water Resources is responsible for
determining whether the end use of treated water in any proposed remedy is beneficial.
As potential remedies are developed. end use options are presented to ADWR for
determination. Some reasons that local reuse options may not be advanced are
availability of a user and cost considerations. Arizona Revised Statute 149-282.D.3
requires that remedial actions be cost-effective. If less expensive beneficial use options
are identified in a feasibility study. it is likely that they will be selected over local reuse.
Local reuse options will be evaluated for potential inclusion in future remedies.
Additional options for alternatives
1)
The GNC suggested that a line of monitor wells along the axis of the plume should have
been included.
ADEQ response: A large number of wells already exist throughout the interim remedy
study area to monitor plume movement. Although additional monitoring wells will be
installed. locating them near the- axis of the plume would not meet the monitoring
objectives of assessing plume capture. .
2)
Allied GNC recommended a combination of Alternative 64R and Alternative 11.
including a scaled-down version of the Alternative 64R portion to capture the SOO part
per billion TCE area.
ADEQ response: A version of Alternative 64R smaller than proposed in the FS would
likely result in incomplete containment of the entire width of the plume. A combination
of alternatives 64R and 11 presents a resource expenditure of a magnitude that would
better serve the entire contaminated area. Evaluation of fmal remedy options will include
facilities to address contamination in the area of Alternative 11. .
3)
Allied had additional recommendations for approaching OU2, including encouraging
aggressive identification and clean-up of downgradient releases, identifying important
data gaps, and developing long-term strategies for low concentration plumes.
ADEQ response: These issues will be factored into ADEQ's approach for identifying
a fmal remedy for the site. ADEQ is already working with Allied. ITI, and Tiernay to
characterize the sources on their respective facilities. The fmt step in identifying a fmal
remedy will be tel Remedial Investigation to identify and fill the data gaps. Approaches
for all sources contributing to the plume. above MCLs, will be incorporated into the fmal
remedy.
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2)
3)
Part n - Comprehensive Response to Specific Legal and Technical Questions
Amount and quality of data
1)
The COP expressed a concern that insufficient data exist to select Alternatives 21, MC
or MR. Tiernay Turbines supported this with a concern that the area around Alternative
MR has not been properly characterized. Several of the PRPs pointed out that the
density of data nearer the Motorola plant is higher than in the western portions of the
site, and the limitations of data in the western portions could not support a remedy
selection. Motorola commented that ample study has been conducted to support an
interim remedy decision. Motorola commented further that insistence on additional study
will only delay plume containment and cleanup, and that complete knowledge of the site
will never be possible.
ADEQ response: The density of data available in the western portions of the site is
sufficient to support an interim remedy decision, regardless of the higher density of data
nearer the Motorola plant. In addition to numerous rounds of groundwater quality
sampling in the area, well iDstallations by both Motorola and ADEQ have provided
geologic infonnation, and an - aquifer test near 27th Street and Adams has provided
sufficient infonnation about the characteristics of the aquifer to develop and evaluate
remedial alternatives. During that aquifer test, Motorola also performed a short-term test
of the ability to reinject water into the aquifer in addition to the ability to withdraw
water.
The PRPs (except Motorola) expressed concerns regarding the existence of a bedrock
ridge, or high, near 32nd Street and Washington. The PRPs feel that the impact the
bedrock high may have on the alternatives has not been adequately researched and that
the bedrock high has not been incorporated into the model. Motorola commented that
the bedrock high does not give sufficient cause to not consider Alternatives MC and MR.
ADEQ response: A report of preliminary studies to characterize the bedrock high was
completed in late February 1994. ADEQ has evaluated this information. The report
verified the existence of the high and that its characteristics are only slightly different
than those assumed during modeling efforts. ADEQ's evaluation of the data concludes
that Alternative 21 would need to. be completely reconfigured to be effective. Alternative
MR may require small changes in reinjection well locations, and those detepninations
would be made during the design phase of the project. Alternative MC would require
minimal consideration of the bedrock high. Alternatives 11 and 11 C, east of the bedrock
high, would not require consideration of the bedrock high during the design stage.
. .
The COP commented that the recent gravity survey to locate the bedrock high produced
data on subsurface bedrock elevations that were somewhat different than the assumptions
placed in the model. The COP recommended that the model be revised to incorporate
the new information prior to implementing an interim remedy at or downgradient of the
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bedrock high.
ADEQ response: As indicated in the previous response, the differences between the
model assumptions and the new bedrock elevation data for the bedrock high do not justify
extensive reconsideration of the preferred alternative. During remedial design. the newly
collected data be considered and added to the model.
4)
Allied and the GNC questioned whether additional site characterization is necessary to
select a remedy in the area of the preferred remedy.
ADEQ response: Enough data exists for each of the alternatives to select an ihterim.
remedy. Data requ~ements specific to the design of the interim remedy may require.
additional hydrogeologic characterization.
5)
Allied expressed a concern that the data gaps in the area near the preferred alternative
reduce the ability to compare cost and performance of the various alternatives.
Confidence in cost and effectiveness are higher where more data exist.
ADEQ response: As seen in responses to other comments. ADEQ is confident in the
data that led to its selection of the preferred alternative. Again. it is true that more data
points exist nearer to Motorola. however sufficient data exist in the western portions of
the site to evaluate effectiveness and select a remedy. EP A guidance for completing
feasibility studies suggests that cost estimates be accurate within -30% to +50%, and the
available data for this site allow the FS to have this accuracy.
6)
A citizen at the public meeting commented that important information regarding the
bedrock ridge was not available for review. . The citizen also commented that water
quality information collected during the bedrock survey was not being provided.
ADEQ response: The bedrock information, with water quality data, was provided in
late February 1994, as it became available to ADEQ. At the request of the PRPs and
the community, the comment period on the proposed plan. was extended to April 6, 1994
to allow time to consider this and other information.
7)
The technical advisor of the GNC at the public meeting stated that it is difficult to advise
his client on a plan where the technical assumptions are outdated, referring to bedrock
conditions and model assumptions.
ADEQ response: ADEQ's opinion of the technical data is presented in.responses to
other comments in this document. In summary t ADEQ believes the technical
assumptions were sufficiently current and accurate to support selection of an interim
remedy.
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Technology concerns
I)
The COP commented that studies have shown that typical pump and treat remedies are
ineffective for restoring aquifers, and questions why in-situ treatments were not
considered.
ADEQ response: The objective of this interim remedy is to contain groundwater
contaminants, not to restore the aquifer. Properly designed pump and treat actions are
very effective at providing containment. In-situ technologies will be considered in the
development of final remedy alternatives. Bioremediation tests at other sites in the
Phoenix area are being closely watched for potential use at this site.
2)
The COP questioned whether ADEQ has taken into account any dense non-aqueous phase
liquid (DNAPL) contamination and the potential of a pump and treat approach to
intensify problems associated with that type of contamination.
ADEQ response: DNAPL contamination consists of undissolved contaminants, or pure
product, which are heavier than water and sink to the bottom of the ~quifer. Most of the
contaminated aquifer at this site contains dissolved contaminants, which move along with
the flow of the water instead of sinking. DNAPL contamination has been observed
beneath the Motorola plant, however OUI is intended to keep that DNAPL from
contaminating downgradient areas. Another potential source of DNAPLs is the
AlliedSignal facility. Trichloroethane (TCA) has been detected in wells at that facility
at 26,000 parts per billion, which suggests DNAPLs may exist, although they have not
been actually observed. Facilities with DNAPL contamination will likely be required to
perfonn remedies similar to Motorola's OUI to keep DNAPLs from contaminating
downgradient areas.
3)
The COP requested a clarification on why a containment remedy is being considered, and
not a restoration remedy.
ADEQ response: The feasibility of complete aquifer restoration will not be possible
to evaluate until the extent of contamination is better dermed.By implementing this
interim remedy, some control of the contamination is gained and additional information
regarding aquifer response to groundwater pumping can be gathered to more effectively
develop restoration strategies. .
4)
The COP requested clarification on the synthetic resin technology proposed for treatment
of air emissions in regard to contaminants captured and removal efficiency.
ADEQ response: As Section 4.7.2 of the FS states, synthetic resin is capable of
capturing VOCs in an air stream, including vinyl chloride. Removal efficiencies listed
in the FS for all technologies are based on professional knowledge and review of actual
applications of the technologies. During implementation of the remedy, monitoring will
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7)
8)
be conducted to ensure proper operation.
5)
A citizen at the public meeting commented on the potential for earth subsidence due to
groundwater extraction.
ADEQ response: The amount of drawdown expected to occur as parl of the preferred
alternative is less than the seasonal fluctuations in water levels occurring in the area.
Therefore the di'awdown would not add to any minute amount of natural subsidence that
might be seen.
6)
A citizen at the public meeting expressed a concern that reinjection will push uncaptured
contaminants further "downstream" and that it will be difficult to monitor where they are
going.
ADEQ response: As proposed in the FS. reinjection associated with the preferred
alternative wm be upgradient of and north of the eX1r3Ction location. The-reinjection will
be designed to provide additional control of contamipants north of the extraction location
and will have little, if any. impact west of the containment line.
A citizen at the public meeting expressed a concern regarding technical difficulties in
operation of OUI that led to releases of vinyl chloride to the air. The comments
included lack of public notification of the event.
ADEQ response: Vinyl chloride is not expected in the area of extraction in the
preferred alternative. However, OU2 will use synthetic resin to treat air stripper
emissions. Synthetic resin will trap vinyl chloride rather than cycling it through the
system as OUI does. OUI is currently operating after modifications were made to
prevent future releases of vinyl chloride. With the sound working relationship that is
developing with the Gateway Neighbors, ADEQ hopes that infonriation of any
unexpected circumstances can quickly get out to the community.
The COP questioned statements on page 5-3 of the FS that OUI is effective. The COP
contends that trends in cont,minant concentrations in wells across the area are similar to
those in OUI extraction wells. therefore declining concentrations do not immediately
suggest effectiveness.
...,"i -'
ADEQ response: The OUI groundwater extraction and treatment system has a similar
purpose to that of OU2. OUI's primary purpose is containment of highly contaminated
groundwater east of 46th Street. The effectiveness of OUI is measured by its ability to
maintain control of groundwater movement, not its ability to reduce' conUiminant
concentrations. The Admini~tive Record contains an Operable Unit Effectiveness
Report prepared in May 1993 that shows, when operational, OUI achieves its purpose.
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The FS Model
1)
A citizen at the public meeting commented that the model was only run for a few of the
64 potential alternatives. .
ADEQ response: 64 alternatives were proposed for the initial screening of final remedy
alternatives. Those 64 alternatives were screened generally on effectiveness,
implementability, and cost. Based on that screening, and the decision to develop an
interim remedy instead of a fInal remedy, fIve alternatives (11, 11C, 21, 64, and 64R)
were advanced for further development in the Feasibility Study. Alternative 64C was
added to the FS after discharge to the Salt River was not considered a benefIcial use of
the treated water. Modeling was conducted on those six alte~tives, and the "no 'action"
alternative.
2)
The COP commented that migration of inorganic contmninants was not modeled during
the FS.
ADEQ response: It was not the purpose of the FS model to predict the extent of
inorganic contaminants. West of the Old Crosscut Canal, fluoride is the only inorganic
contaminant detected above Maximum Contaminant Levels in a few monitor wells, and
, those locations are all east of the Grand Canal. Movement of arsenic, fluoride, and
nitrates was modeled in the Draft Report. Investigation of Inorganic Constituents in
Ground Water, which is part of the Administrative Record for this site.
3)
The COP commented that it is unclear from the modeling what aquifer units these
containment alternatives are designed to address.
ADEQ response: The volume of groundwater in the alluvium is estimated to be 30 to
several hundred times as much as that contained in the same cubic volume of bedrock.
Therefore, most of the VOC contaminants will be found in the alluvium. Also, VOC
contaminants in groundwater would tend to migrate farther in alluvium than in bedrock.
For these reasons, the FS alternatives were designed to achieve containment primarily
in the alluvium. However, conta~ent is expected to be achieved to a signifIcant depth
into bedrock.
4)
The COP commented that, while the model is intended to provide a relative comparison
of effectiveness of the alternatives, the FS presents quantitative estimates of pounds of
TCE removed.
ADEQ response: Comparing the relative effectiveness could have involved a different
approach, such as assigning "high", "medium", "low", or "good" , "better", "best" to the
alternatives. By providing a numerical estimate, the reader is able to Consider how much
better one alternative is than another, rather than simply noting that one is ranked higher.
This becomes very important when considering the interrelation of all factors including
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8)
9)
implementabiIity, effectiveness, and cost.
5)
The COP questioned how the plume sizes depicted in various figures showing 5, 10, and
20 year intervals in Appendix F (modeling) were generated and what they represent.
ADEQ response: For each alternative evaluated in the FS, figures representing the
contaminant plume after 5, 10, and 20 years of operation were generated by the model.
6)
The COP questioned why sources at the Motorola plant other than the drywell in the
courtyard were not included in the model. The COP also questioned whether the
courtyard source or OU 1 should be considered the start of the model.
ADEQ response: It is important to note that the model used in the FS did not include
any specific sources, Motorola or otherwise. Modeling of the alternatives included
putting actual water quality data from 1992 into the model and then running each
alternative into the future. The benefit of this approach is that the cumulative impacts
of all historic sources, at Motorola and other companies, are represented by the 1992
water quality data.
7)
The COP questioned whether contaminant movement since the model was ron has been
considered in determining the effectiveness of the alternatives.
ADEQ response: The modeling of each alternative begins in the year 1995 to account
for contaminant movement during the period of design and construction. This initial
condition is represented by Figure F.23. The effectiveness of each alternative was
evaluated taking migration of contaniinants into account. .
The COP expressed concern that the model results for the preferred alternative indicate
that "extremely high" levels of TCE still exist after 20 years of operation. They also
note that TCE is shown still coming from the Motorola plant after 10 years of operation.
ADEQ response: The purpose of this interim remedy is to control the movement of
contaminants. The "extremely high" levels of TCE identified in the comment are within
the capture zone.
TCE shown still coming from the Motorola plant (Le., downgradient of OUl) is
estimated due to residual TCE in the aquifer. OUI is expected to contain contamination
at the Old Crosscut Canal, however concentrations within the OUI capture zone will not
likely be decreased to below 5 parts per billion within 20 years.
The COP, Allied, and Tiemay all expressed concerns about the assumption in the model
that the aquifer is in a "steady-state" condition, (Le., that erratic changes in groundwater
conditions do not exist). Allied and Tiernay identified flood flows in the Salt River as
one factor that is not accounted for in the steady-state assumption.
B-19
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10)
11)
12)
ADEQ response: Over the past 30 years, the Salt River has flowed 641 days at a rate
at Granite Reef Dam considered to cause flow in the Salt River near Sky Harbor Airport.
The 641 days amounts to 5.9 percent of the 30-year period from 1963 to 1993. 214 of
those days (about one-third) were in the 1992-1993 period. Groundwater levels were
observed frequently from October 1992 to March 1993. A comparison of this
groundwater level data to data prior to flow in the Salt River concludes that river flow
did not have significant impact on regional groundwater flow direction. Also, significant
changes to upstream dams being made by Salt River Project, will reduce the likelihood
of flooding and any potential impact flooding would have on groundwater flow.
The COP questions how ADEQ considers the model to be appropriate when ADEQ staff
have reviewed the model and consider it inadequate. The COP requested that comments
prepared by ADEQ staff be addressed in this responsiveness summary.
ADEQ response: The COP specifically references comments made by Y ongshou Luo
of ADEQ's Technical Services Hydrology Unit. Mr. Luo's comments were on the
modelling approach originally taken by Motorola, to JIlodel historic sources from the past
into the present and future. His comments served to identify limitations in the model that
ADEQ considers when evaluating the outputs. Mr. Luo's comments were also important
in the decision to start the model using actual water quality data, rather than sources
modeled through time. Because the FS modeling approach was changed due to Mr.
Luo's comments, his comments. on the previous modeling approach will not be
specifically addressed in this responsiveness summary.
The COP suggested that a detailed independent review of the model be done.
ADEQ response: ADEQ reviews all aspects of Motorola's modeling efforts. Frequent
meetings during model development have been necessary, and ADEQ required
modifications to the model as necessary. For evaluating potential alternatives for the
fmal remedy, ADEQ has approached the group of PRPs to form a modeling committee.
The purpose of that committee will be to reach a consensus on modeling issues including
which model to use, \rarious parameters, and standardized data formats. This committee
should be able to identify agreeable modeling conditions to identify future remedies.
The COP requested clarification. of statements in the FS that the Motorola plume has
been modeled to extend to 24th Street while field data shows a much larger plume. ~ .
ADEQ response: Motorola initially modeled the migration of contaminants historicidly
released only at the 52nd Street plant from the 1950's to the present. This showed a
plume from the 52nd Street plant to 24th Street. That initial modeling is not consistent
with field data because it did not include uncharacterized sources, such as potential
sources at AlliedSignal, I'IT Cannon, and Tiernay Turbines. Other reasons the initial
modeling did not reflect field conditions may be limitations of the initial assumptions
about the nature of the releases at the Motorola plant, and limitations of the model
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identified elsewhere in these comments and in past comments made by ADEQ staff.
Changing the model approach in the FS to use current groundwater data, instead of
modeled estimates, allowed all sources to be considered and eliminated this discrepancy.
13)
Allied questioned how ADEQ will demonstrate that the model is suitable, considering the
limitations.
ADEQ response: ADEQ has guided the development and use of the model. ADEQ
. understands the limitations, and has made adjustments necessary to evaluate interim
remedy alternatives. In that purpose, the model bas been a useful and appropriate tool,
although not perfect. Additional modeling will be conducted during remedial design, and
may result in modifications to the remedy, if necessary to meet the objectives of this
interim remedy. .
14)
Allied commented that the use of rising l1ead tests does not provide a basis to evaluate
changes in hydraulic conductivity with direction.
ADEQ response: Pumping test data, not rising head tests, were used to evaluate changes
in hydraulic conductivity with direction. The pumping tests, the largest of which was
conducted at well DM 518 between the locations of alternatives 21 and 64, indicated that
there is no change in hydraulic properties with horizontal direction from the pumping
well.
15)
Allied expressed concern that the model inputs were based on interpretations of 1992
groundwater quality data, rather than the actual data.
ADEQ response: Figures F.14 and F.15 in the FS represent late 1992 contours of
contaminant concentrations in alluvium and bedrock as they were input to the FS model.
Since actual groundwater quality data do not exist for each of the 81,000 cells in the
model, professional judgements were made using water quality data that do exist to
generate the contours and develop data for use in the model. Several anomalous data
points were excluded during generation of the contours tQ allow smoother contour lines,
necessary for input to the model. Those anomalies may represent undefmed sources or
variations in subsurface conditions. The model was not intended to precisely predict
future groundwater quality. The methods used in the FS model are sufficient to allow
a comparison of remedial alternatives.
16)
Allied expressed concern that only 1992 water quality data was used to calibrate the
model and not historic data as well. Allied. also commented that, while 1992 water
quality data were used, 1992 groundwater elevations were not used because they were
abnormal.
. .
ADEQ response: 1992 groundwater quality data were used because numerous
groundwater monitoring wells were installed during 1992, which greatly expanded the
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water quality data base and the understanding of regional groundwater quality. 1992
water elevation data were not used in the model since the preceding period was unusually
wet and not representative of normal conditions in the area. This approach allowed both
the water quality data and the water elevation data to be reasonably representative and
allow relative comparisons between alternatives in the FS.
ADEQ contaminant contour maps
1)
In Allied's comments, they refer to contaminant contour maps generated by ADEQ staff
as a "conceptual model".
ADEQ response: The contaminant contour maps prepared by ADEQ staff in August
1993 are nota model of any kind. The maps merely represent the extent of
contamination in groundwater based on groundwater sampling in late 1992. The maps
are used by ADEQ~ along with other information, to create a conceptual model for the
site.
2)
Allied commented that ADEQ's contour maps present an unlikely worst case scenario
since the single highest detected concentrations in multi-depth wells were used.
ADEQ response: Using the highest detected concentrations from multi-depth wells to
prepare a two-dimensional map of the plume is the most conservative approach and most
protective of the public health and the environment. The contour maps were rigorously
peer-reviewed by four ADEQ staff hydrologists. ADEQ feels that the maps accurately
reflect the field conditions. ADEQ intends to update the maps semi-annually as new data
are generated.
3)
Allied commented that the bedrock high recently investigated was not given sufficient
weight in the ADEQ's contour maps.
ADEQ response: At the time that the maps were generated, ADEQ only knew of the
potential that the bedrock high might exist. This potential was considered during the
creation of the maps. Results of the bedrock high investigation will be considered in
future updates ()f the maps.
4)
Allied questioned the technique used by ADEQ in generating the contour maps and
suggested a logarithmic approach be taken rather than an apparent "eyeball" approach.
ADEQ response: As indicated in previous responses, the maps were peer-reviewed by
four staff hydrologists. Their combined professional expertise was used to generate maps
that ADEQ is confident with. Figure 1.6 in the FS was used in the evaluation of
alternatives for this interim remedy, not the contour maps generated by ADEQ.
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S)
Allied commented that there is no support of ADEQ's contour maps contained in the
Administrative Record for the site.
ADEQ response: The contour maps were generated to defme the extent of
contamination in the East Washington Water Quality Assurance Revolving Fund area.
Supporting documentation, in the fonn of laboratory data sheets from the groundwater
quality analysis, can be found in files for that site. The memo containing the contour
maps is in the Administrative Record and provides a tabular summary of the groundwater
quality data and a textual explanation of the maps.
6)
Allied commented that the same data limitations that plague the FS model impact
ADEQ's contour maps and overestimate the downgradient distance of the Soo part per
billion TCE contour. Allied contends that, using a logarithmic mapping approach, the
SOO part per billion TCE contour ends near 24th Street.
ADEQ response: Allied's inteIpretation is not supported by groundwater quality results
from wells installed by ADEQ west of Interstatt: 10. In the maps, those wells are
identified as numbers 10 and 13, and they indicate concentrations of TCE in 1992 of 430
and 560 parts per billion, respectively.
The FS and Comparison of Alternatives
1)
The COP commented that estimates of TCE removed for each alternative don't correlate
with estimates of recovered solvent plus air emissions.
ADEQ response: The COP is correct in its observation that there is no clear correlation
between the estimates of TCE removed from the aquifer (see Figure 6.11 and Table 7.6
of the FS) and the sum of waste solvents recovered and VOC air emissions (see Table
7.2 of the FS). This lack of apparent correlation occurs because the estimates were
prepared for different pUIposes using different methodologies.
The groundwater flow and transport model was used to calculate the quantities of TCE
removed from the aquifer (see Figure 6.11 and Table 7.6 of the FS) under each
alternative. These estimates w~re used to ~mpare relative performance of the
alternatives, rather than to provide a precise estimate of mass removed. The amount of
solvents entering the treatment plant that is either recovered as waste solvent or em1tted
to the air (in compliance with air emission limits) was estimated based on the highest late
1992 concentrations observed near the proposed extraction well locations. The resulting
numbers represent initial rates of waste solvent recovered and VOC air emissions, both
expressed in lbs/day, and are intended to be conservative (i.e., on the.'high side) to
anticipate the maximum amount of wastes to be handled at the treatment plant. Thus,
for any alternative, if you take the sum of initial rates of solvent recovered and VOC air
emissions and multiply it by the number of days in 20 years, the resulting figure is much
greater than the model~generated estimate of TCE mass removed.
B-23
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4)
5)
6)
2)
Allied commented that the estimates of TCE removed are misleading due to data
limitations and suggests that a range should have been provided instead of a specific
number.
ADEQ response: See the response to the preceding question. The estimates of TCE
removed were not intended to be precise, but to allow comparative analysis between the
alternatives in the FS.
3)
The GNC commented that the estimates of TCE removed did not include TCE removed
from the bedrock portion of the aquifer. Alternative 11 would remove TCE from the
bedrock, while 64R would. not.
ADEQ response: See response to question 3 under the "The FS Model n category.
The COP questioned whether the costs to decommission each of the alternatives was
included in the cost estimates. .
ADEQ response: The costs of decommissioning equipment were not included because
the are not relevant until the fmal remedy is known.
The COP commented that detailed cost information was provided only for Alternative 11,
and that all costs should have been included. This concern was also presented by a
citizen at the public meeting.
ADEQ response: EP A guidance on FS reports suggests summary cost information for
all alternatives be provided in the main body of the report and inclusion of detailed cost
information of better alternatives as an appendix. Appendix D of the FS presents
detailed cost calculations for Alternative 11. This alternative was agreed upon for the
appendix by ADEQ, EPA, and Motorola because it included virtually all of those
components that are found in the other alternatives. One component of Alternative 11,
activated alumina adsorption for treatment of fluorides, is unique to that alternative,
further supporting its use as an example of detailed cost calculations. While total costs
for each alternative vary, the unit costs (i.e., per extraction well, injection well, air
stripper, piping, etc.) remain constant for each alternative. ADEQ and EPA reviewed
cost information to ensure that unit costs were consistently applied. Also, Dames &
Moore made the worksheets used to estimate costs for each of the alternatives in the FS
available to the PRPs and the GNC during a coordination meeting on January 26, 1994.
The COP commented that due to the conceptual nature of the alternatives".costs may be
underestimated. .
ADEQ response: The purpose of developing costs in the FS is to. provide estimates
suitable for comparing alternatives. The cost of the selected alternative will be fully
developed during remedial design. EP A guidance for completing f~ibility studies
B-24
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2)
3)
suggests that cost estimates be accurate within -30% to +50%, and this FS is consistent
with guidance.
7)
The COP expressed concern that specific aquifer parameters were not included in the FS.
ADEQ response: Specific aquifer parameters are included in other documents in the
Administrative Record, including the October 1993 Aquifer Test Report. Well DM-518.
National Contingency Plan (NCP)
1)
The COP recommended that the NCP be used to guide the remedial activities at this site
rather than 1988 EP A guidance, since portions of the guidance have been superseded or
changed.
ADEQ response: In providing regulatory oversight of the remedial activities at the site,
ADEQ and EP A ensure that requirements of the NCP are met. The particular FS
reference cited by the COP in the comments is to the area where the nine criteria for
evaluating remedial alternatives are id~ntified. The criteria in the 1988 EPA guidance
and the NCP are identical.
The COP commented that ADEQ and EP A have stated that they are exempt from certain
NCP requirements when selecting an interim remedy. Citations to legal authority were
requested.
ADEQ response: ADEQ and EP A have never claimed that they are exempt from NCP
requirements, but rather that the NCP provides for waiver of certain requirements (i.e.,
ARARs) when selecting an alternative that is an interim measure [40 CFR
300.430(t)(I)(ii)(C)]. This type of waiver is also provided for in CERCLA
[~121(d)(4)(A)]. .
The remedial action selected for Operable Unit 2 is intended to limit further migration
of contaminated groundwater. This is considered to be an interim action, and cleanup
of the aquifer is outside the scope of this remedy. Therefore, aquifer cleanup standards
(which would typically be ARARs for a groundwater cleanup remedy) do not apply to
the selected remedy. As a result, ADEQ and EPA are not proposing to waive any
ARARs.
The COP commented that the NCP contains different requirements for "removal" actions
and "remedial" actions. The COP's opinion is that this is a removal action and that some
NCP requirements are left to be met. The features that distinguish it as a'removal are:
(1) The interim remedy is not expected to achieve ARARs in the groundwater and there
has been no waiver of ARARs; (2) it does not appear to be an incremental portion of a
comprehensive remedial action plan; (3) it has been justified solely. on the basis of
protecting public health from an allegedly imminent risk if action in not implemented;
B-25
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(4) a limited group of response technologies were considered; and (5) the response action
was selected without benefit of complete site characterization and other analyses required
for "remedial" actions.
ADEQ response: The selected response action is considered to be a remedial action, not
a removal action. Either type of response action may be justified when a release of
hazardous substance poses a threat to public health.
The groundwater containment remedy for OU2 was selected consistent with the RIfFS
and remedy selection process for remedial actions outlined in section 300.430 of the
NCP. One of the program management principles stated in that section of the NCP is
that sites should generally be remediated in operable units when phased analysis and
response is appropriate given the size and complexity of the site. There is no requirement
that operable units be part of a "comprehensive remedial action plan", but only that they
should not be inconsistent with nor preclude implementation of the expected final
remedy. ADEQ believes that the selected remedy meets these criteria with respect to
potential fmal remedies for groundwater contamination at the site.
Neither the NCP nor EPA guidance envision that "complete site characterization" will
be achieved at the time an operable unit is selected, particularly an interim action
remedy. The FS evaluated a full range of technologies for containment, treatment, and
disposal of treated groundwater within the context of a remedial action whose objective
is containment of contaminated groundwater (versus cleanup of the aquifer).
4)
The COP identified a portion of the NCP that allows staged implementation of response
actions "when early actions are necessary or appropriate to achieve significant risk
reduction quickly, when phased analysis and response is necessary or appropriate given
the size or complexity of the site, or to expedite the completion of total site cleanup".
The COP requested clarification on whether this interim remedy is a phase of the
remediation and how it achieves significant risk reduction.
ADEQ response: Yes, this interim remedy is a part of a phased approach. The size and
complexity of this site meet the referenced criteria identified in the NCP for
implementing a phased approach. Risk reduction will be achieved by limiting the further
migration of contaminants (Le., by reducing toxicity, mobility or volume by treatment).
This phase, OU2, follows OUI which contains the highest levels of contaminants to near
the Motorola plant.
5)
Allied expressed a concern that the uncertainties associated with Alternative 64R
. invalidate its selection as being inconsistent with the NCP.
ADEQ response: The" Amount and quality of data" section beginning on page 13 of
these responses discusses these concerns more specifically. As the responses indicate,
there is sufficient information to support and proceed with this interim remedy.
B-26
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6)
The COP commented that the goals identified in the FS are broad generalizations and do
not meet the requirements of the NCP. .
ADEQ response: The remediation goaJs are identified in the FS on page 2-10 and
reiterated in the Record of Decision. They are described in terms of containing
migration, treatment of extracted groundwatet, and achieving ARARs. These objectives
are appropriate for the scope of the interim remedial action being considered and are
fully consistent with the NCP and EPA guidance for interim remedial actions.
Applicable or Relevant and Appropriate Requirements (ARARs)
1)
The COP commented that the interim remedy will not meet all ARARs and the FS does
not discuss waivers of those ARARs.
ADEQ response: Since the OU2 action is an interim action, chemical-specific cleanup
requirements for the aquifer, such as attaining Maximum Contaminant Levels as would
be ARARs for a fmal remedy, are beyond the scope of this interim action. Since aquifer
cleanup requirements are not ARARs for this interim action, no ARARs waivers are
needed.
2)
The COP's comments indicate they are aware of an October 20, 1992 letter specifying
potential ARARs for the remedy. The COP comments ask if further ARARs
development has been conducted since then.
ADEQ response: ARARs are identified in the Record of Decision. The proposed
ARARs in the October 1992 letter have been reviewed and updated as changes in
requirements are identified. One ARAR change identified by ADEQ, as well as the COP
in another comment, is that Arizona Health-based Guidance Levels are not ARARs. The
fmalized list is presented in Section 10 of the Record of Decision.
3)
The COP commented that the ARARs identified in the FS are incomplete because they
cover only ARARs for the aquifer and not for other me4ia and activities.
ADEQ response: The COP's comment refers to Table 2.4 specifically, which lists
chemical-specific ARARs for groundwater. These ARARs also Jimit the levels of
contaminants that can be discharged (or reinjected) to the aquifer. A. dis~sion of
action, location, and chemical specific ARARs is contained in sections 2.4 and 2.5 of the
FS.
Other legal concerns:
1)
The COP commented that, since the remedy is being conducted "on-site", air emissions
from Motorola's manufacturing processes and OUI should be added to the potential
emissions from this remedy and treated as one source.
B-27
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"'
4)
5)
ADEQ response: According to the Maricopa County Air Pollution Control Board, air
emissions from this remedy would be considered a separate source if the treatment
facilities are outside contiguous property owned by Motorola. ADEQ will encourage that
appropriate permits be obtained for this remedy when the application process does not
interfere with a timely response, however CERCLA (~121(e» and the NCP (40 CFR
300.400(e) allow that permits do not have to be obtained within the NPL site as long as
the substantive requirements of the permits are met.
2)
The COP pointed out that Motorola's intent to discharge a backwash stream from the
groundwater treatment system to the. COP sewer system will require a permit.
ADEQ response: CERCLA requires that on-site response actions meet the substantive
requirements of permits, although applying for permits is not required. However, ADEQ
will encourage that permits be pursued unless the application process inhibits a timely
response. ADEQ appreciates the COP's effort to identify this need.
3)
The COP further clarified the infeasibility of the beneficial use option of discharge to
storm drains which lead to the Salt River by citing 33 U.S.C U342(P)(3)(B)(ii). Also,
the COP commented that the discharge would not be allowed by COP without a National
Pollution Discharge Eliminations System (NPDES) permit.
ADEQ response: This end use option was determined by the Arizona Department of
Water Resources not to meet the beneficial use requirement and ADEQ removed it from
consideration. ADEQ nonetheless appreciates additional information to clarify
requirements that would apply to alternatives evaluated in the FS.
The COP noticed a typographical error in the FS citing Arizona Aquifer Water Quality
Standards as R18-11-495 instead of R-18-11-405. The COP also commented that
references to federal Maximum Contaminant Levels (MCLs) should be replaced by
references to Arizona Aquifer Water Quality Standards. .
ADEQ response: ADEQ appreciates the clarification .and will ensure appropriate
citations in the list of ARARs. Arizona Revised Statute ~49-223 requires that MCLs be
adopted as Arizona Aquifer Water Quality Standards within one year of establishment
by EPA, therefore MCLs are equivalent to Arizona Aquifer Water Quality Standards.
The GNC expressed a concern that implementation of the preferred alternative may force
litigation among PRPs which could delay meaningful cleanup.
ADEQ response: ADEQ cannot control the decisions by interested parnes to file
lawsuits. This interim remedy was selected based on criteria specified in the NCP.
Formal legal agreements will be reached with those parties expected to implement OU2,
or enforcement action will be taken to ensure timely response.
B-28
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D.
2)
3)
REMAINING CONCERNS
1)
A citizen commented that social and political activists with no scientific background cause
hysteria regarding these sites.
ADEQ response: An increasingly important part of ADEQ's mission is to increase
community awareness regarding these environmental hazards. With increased awareness,
potential hysteria can be avoided.
A citizen commented that ADEQ personnel are political appointees who are not qualified
to manage these projects.
ADEQ response: The only appointed personnel at ADEQ are the Director and the
individual Division Directors. All other personnel received their employment through
the State personnel system process for covered employees. No one person manages these
Superfund sites. Staff with varied backgrounds, including hydrology, geology, resource
management, civil engineering, chemical engineeriI}g, toxicol<;>gy, and legal backgrounds
are consulted regularly in the normal operation of these projects.
A citizen commented that there are much bigger social issues than Superfund, such as
housing, hunger, and alcohol and drug abuse.
ADEQ response: These other issues are beyond the mission of the ADEQ and beyond
the response authority of CERCLA. Other state and federal programs exist to address
these issues.
B-29
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ATTACHMENT
Community involvement activities at Motorola 52nd Street, since late 1991
Fact sheets:
March 1992: Information on ADEQ conducted soil gas investigations
Summer 1992: ADHS Risk Assessment and soil gas results
Summer 1993: Introduction of area-wide plume map
Winter 1994: Proposed Plan for Operable Unit Two
February, 1994: Brief notice of comment period extension
Large events:
December 9, 1991: Informational meeting at Balsz Elementary School
July 13,14,15 1993: Series of open houses regarding plume map
January 25/27, 1994: Open houses regarding Proposed Plan for OU2
February 3, 1994: Formal public meeting regarding Proposed Plan for OU2
.c.i!.izens Comm~ttee meetings (various topics):
4/1/92, 4/8/92, 4/29/92, 5/20/92, 6/22/92, 7/22/92, 8/5/92, 8/19/92, 9/22/92, 10/22/92,
11/19/92, 12/17/92, 1/21/93 I
Informal sessions with Gateway Neil!hborhood Coalition:
5/19/93: Reception for TAG committee
6/9/93: Library search
6/30/93: Discussion of plume map fact sheet
7/12/93: Preview of open house presentations
2/24/94: Clarifications on Proposed Plan for OU2
B-30
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