United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R09-89/045
September 1989
4>EPA Superfund
Record of Decision:
Litchfield Airport Area, AZ
-------
50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R09-89/045
3. Rodpienf • A€OM*lofi No.
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Litchfield Airport Area, AZ
Second Remedial Action - Final
5. Report Date
09/26/89
7. Author!*)
& Performing Organization Rept No.
9. Performing Organization Nun* md Addraw
Pro|*cCT**k/Work Unit No.
11. Contr*ct
-------
16. Abstract (Continued)
I
PA/ROD/R09-89/045
itchfield Airport Area, AZ
The selected remedial action for the northern portion of the site includes treatment of
soil with VOC soil gas levels greater than 1 ug/kg using soil vapor extraction (SVE); and
ground water pumping and treatment using air stripping, liquid phase granular activated
carbon, and granular activated carbon polishing on the air emissions, followed by
reinjection or discharge of treated ground water to the municipal water system. Remedial
activities for the southern portion of the site include treatment of 284,100 square yards
of VOC-contaminated soil using SVE; and ground water pumping and treatment using air
stripping and wellhead treatment, followed by discharge to the municipal water system.
The estimated present worth cost for this remedial action ranges between $30,227,000 and
$31,693,000. O&M costs will be determined during the remedial design.
-------
RECORD OF DECISION
PHOENIX-GOODYEAR AIRPORT
SUPERFUND SITE
GOODYEAR, ARIZONA
September 1989
RDD63605.RA
Work Assignment 30-9L19.0
NONDISCLOSURE STATEMENT
This document has been prepared for the U.S. Environmental
Protection Agency under Contract No. 68-01-7251. The mate-
rial contained herein is not to be disclosed to, discussed
with, or made available to any person or persons for any
reason without the prior express approval of a responsible
official of the U.S. Environmental Protection Agency.
-------
CONTENTS
Page
Declaration for the Record of Decision 1
Declaration 5
Record of Decision Concurrence Page 7
1 Site Description 1-1
2 Site History and Background 2-1
Site History 2-1
Site Characterization 2-2
Exposures 2-10
Toxicity 2-14
Risk 2-16
Cleanup Levels and ARARs 2-20
3 Enforcement History 3-1
Phoenix-Goodyear Airport and Former 3-1
GAG Facility
UniDynamics Phoenix, Inc. 3-2
4 Community Relations History 4-1
5 Alternatives Evaluation 5-1
Phoenix-Goodyear Airport and the 5-1
Former GAG Facility
UniDynamics Phoenix, Inc., Facility 5-53
6 References 6-1
Appendix A. Index of Administrative Record A-l
Appendix B. Response Summary B-l
Tables Page
2-1 Comparison of the Applicable or Relevant 2-4
and Appropriate Requirements and Other
Criteria to Groundwater Data
2-2 Comparison of the Applicable or Relevant 2-12
and Appropriate Requirements and Other
Criteria to Soil and Air Data
2-3 Summary of Exposure Routes and Risks 2-17
RDD\R206\004.50-2
-------
CONTENTS (Continued)
Tables (Continued) Page
2-4 Estimated Excess Lifetime Cancer Risk Due 2-20
to TCE Exposure Based on Implementing the
No Action Alternative
2-5 Legally Applicable State and Federal 2-22
Requirements and Other Criteria for
Groundwater
5-1 Estimated Capping Areas 5-10
5-2 Estimated Surface Areas and Number of Wells 5-16
for Soil Vapor Extraction
5-3 Soils Remedial Action Screening Summary 5-17
5-4 Summary of Soils Remedial Action Alternatives 5-19
5-5 Soils Remedial Actions—Cost Summary 5-21
5-6 Summary of Engineering Constraints 5-26
for Water End Use Alternatives
5-7 Public Health and Environmental Considera- 5-28
tions by Water Use Type
5-8 Summary of the Screening of Groundwater 5-29
Aquifer Remedial Actions
5-9 Summary Table of Groundwater Extraction 5-30
Alternatives
5-10 Detailed Analysis of Alternatives-- 5-31
Effectiveness
5-11 Detailed Analysis of Alternatives-- 5-37
Implementab ility
5-12 Detailed Analysis of Alternatives—Cost 5-41
5-13 Summary of VOC Removal Technologies 5-44
Screening
5-14 Treatment System Costs--Air Stripping 5-47
5-15 Treatment System Costs—Activated Carbon 5-48
RDD\R206\004.50-3
-------
CONTENTS (continued)
Tables (continued) Page
5-16 Total Treatment Costs 5-49
5-17 End Use Alternatives--Cost Summary 5-51
5-18 Technical Feasibility Screening of 5-57
Technologies and Processes for the
Soils Objective
5-19 Soils Remedial Actions—Cost Summary 5-59
5-20 Evaluation of Soil Options 5-61
5-21 Technical Feasibility Screening of 5-65
Technologies and Processes for the
Groundwater Quality Objective
5-22 Summary of the Screening of Groundwater 5-70
Aquifer Remedial Actions
5-23 Detailed Analysis of Groundwater 5-72
Alternatives
5-24 Detailed Cost Analysis for Groundwater 5-78
Alternatives
Figures Page
1-1 Site Location Map 1-3
1-2 Summary of Major Activities at Phoenix- 1-5
Goodyear Airport
2-1 Cross Sectional View of Geology 2-3
2-2 Organic Compounds Above ARAR Concentrations-- 2-8
Subunit A
2-3 Organic Compounds Above ARAR Concentrations— 2-9
Subunit B
2-4 Organic Compounds Above ARAR Concentrations-- 2-11
Subunit C
2-5 Exposure Pathway and Receptor Summary 2-15
RDD\R206\004.50-4
-------
CONTENTS (continued)
Figures (Continued) Page
5-1 . Target Area 1 for Soils Remedial Action 5-3
at Phoenix-Goodyear Airport and Former
GAG Facilities
5-2 Target Area 2 for Soils Remedial Action 5-5
at Phoenix-Goodyear Airport and Former
GAG Facilities
5-3 Target Area 3 for Soils Remedial Action 5-7
at Phoenix-Goodyear Airport and Former
GAC Facilities
5-4 Capping Alternative Area Delineated by Soil 5-11
Sampling Analyses at Phoenix-Goodyear
Airport and Former GAC Facilities
5-5 Capping Alternative Area Delineated by 5-13
Elevated Soil Gas at Phoenix-Goodyear
Airport and Former GAC Facilities
5-6 Groundwater Remedial Action Alternatives 5-23
5-7 Target Areas A, B, and C for Soils Remedial
Action at UniDynamics 5-55
RDD\R206\004.50-5
-------
DECLARATION FOR THE RECORD OF DECISION
SITE
Phoenix-Goodyear Airport (PGA) Superfund site, Goodyear,
Arizona.
PURPOSE
In accordance with the National Contingency Plan-, the Com-
prehensive Environmental Response, Compensation and Liabil-
ity Act of 1980 (CERCLA), and the Superfund Amendment and
Reauthorization Act of 1986 (SARA), potential remedial
actions have been developed and evaluated for the PGA site.
This decision document represents the U.S. Environmental
Protection Agency's (EPA) preferred final remedy and reme-
dial actions for the entire site. A Record of Decision for
the Section 16 Operable Unit (OU) addressing groundwater
contamination in Subunit A of the Upper Alluvial Unit (see
Figure 2-1) within Section 16 was signed in September 1987.
The Section 16 OU Record of Decision is consistent with the
selected remedial actions represented in this Record of
Decision. The Arizona Department of Environmental Quality
and the Arizona Department of Water Resources concur with
these selected final remedies.
This decision is based on the administrative record for the
PGA site, which includes the results of the Remedial Inves-
tigation (RI) conducted by EPA, Unidynamics Phoenix, Inc.
(UPI), and the Goodyear Tire and Rubber Company, and the
Feasibility Study (FS) conducted by EPA and UPI. Appendix A
identifies all the items contained in the Administrative
Record upon which the selection of the preferred remedial
actions are based.
DESCRIPTION
The PGA site is located approximately 17 miles west of
Phoenix, Arizona, in the western part of the Salt River
Valley. The site covers a total area of about 35 square
miles (Figure 1-1). Except for the airport, which is owned
by the City of Phoenix, the PGA site lies almost entirely
RD/R85/025.50
-------
within the City of Goodyear. The City of Avondale occupies
about 2 square miles along the eastern border of the site.
Current land uses consist predominantly of agriculture, but
also include residential and industrial. Future land uses
are predicted to become more residential. The combined
population of the area was 30,000 people in 1985. The City
of Goodyear expects to grow at a rapid pace, exceeding
140,000 people within the boundary of the PGA site in 20
years. Clusters of residential development are occurring
west of the airport.
PREFERRED PLAN AND RATIONALE
A groundwater divide roughly follows the alignment of Yuma
Road, effectively dividing the site into two distinct
halves, north and south. UniDynamics Phoenix, Inc., under-
took investigation of contamination in the north part of the
site, while Goodyear Tire and Rubber Company and EPA com-
pleted the investigation for the south portion of the site.
The preferred plan of action and rationale were developed
for each portion of the site. Remedial actions for Sub-
unit A groundwater in the south portion of the site were
developed during an operable unit feasibility study com-
pleted in 1987. EPA selected extraction and treatment with
air stripping as the preferred remedy. Goodyear Tire and
Rubber Company is currently undertaking the design of the
operable unit (OU) remedial action. The OU remedial action
is consistent with the preferred plan as stated below.
Therefore, the OU and the following remedies constitute the
final remedy.
Based on the PGA RI/FS, the preferred alternative for the
south portion of the site consists of extraction and treat-
ment of Subunit B/C groundwater, and soil vapor extraction
for the vadose zone.
o The groundwater alternative proposes the continued
use of 20 existing wells for extraction and the
aduition of 3 more extraction wells. This alter-
native, which includes air stripping without car-
bon absorption, would result in reducing VOC con-
centrations in treated groundwater to levels equal
to or less than Applicable or Relevant and
Appropriate Requirements (ARARs). A central plant
will be; constructed to treat the water from all
but one of the extraction wells. The remaining
well will have treatment at the wellhead since it
lies some distance from the airport. The treated
RD/R85/025.50
-------
water will be provided to current users of the
extraction wells, with the additional flow from
the three new wells going to the Cify of Goodyear
for municipal use. Total present worth cost for
extraction and treatment is estimated at
$9,160,000.
o Soil vapor extraction (SVE) for the area
containing 99 percent of the mass of contaminants.
This area corresponds approximately to Target
Area 2 in the RI/FS. Under this alternative, VOCs
would be extracted through a system covering
approximately 284,100 square yards. Pilot testing
conducted at this area of the site indicates that
soil vapor extraction is an effective means of
removing VOC contamination from the unsaturated
vadose zone, thereby removing a source of
potential groundwater contamination. All SVE
units will be equipped with emission controls.
Costs for SVE are estimated to range from
$3,904,000 for a phased implementation to
$5,370,000 for a full-scale implementation.
Based on the UPI RI/FS, the preferred alternatives for the
northern portion of the site are the following:
o For groundwater, pump and treat Subunit A and Sub-
unit C to equal to or less than ARARs. Ground-
water treatment will consist of air stripping,
followed by liquid phase granular activated carbon
with granular activated carbon polishing on the
air emissions. The end use will consist of either
reinjection (treated groundwater from Subunit A)
or incorporation into the community potable water
supply (treated groundwater from Subunit C). The
pumping rate for both subunits will be specified
in the system design.
If, in the implementation of the remedial action,
EPA determines that air stripping cannot treat
methyl ethyl ketone (MEK) to the level required by
the ARARs, then hot air stripping and scale
control methods will be employed unless EPA
determines that the technology is impracticable.
If the technology to treat MEK is impracticable,
EPA will waive compliance with the MEK ARAR
pursuant to CERCLA Section 121(d)(4), and set an
alternative limit that is protective of human
health and the environment.
RD/R85/025.50
-------
Total cost is estimated at $12,157,000 for the
Subunit A alternative and $1,870,000 for the
Subunit C alternative.
The soils will be treated with soil vapor extrac-
tion with emission controls. The target area con-
sists of the area where VOCs were detected in soil
samples and the area where soil gas samples quan-
tified VOCs greater than 1 ug/1. The area may be
expanded or reduced to include removal of 99 per-
cent of the contaminants. Excavation and
treatment may be required to remove residual
contamination where soil vapor extraction is not
effective. This includes soils contaminated
with MEK and acetone.
SVE costs are estimated to be $3,136,000. Costs
for excavation and treatment will depend on the
volume requiring removal which will be decided
once the effectiveness of the SV1 is determined.
A total unit cost for treatment and disposal is
estimated to be $715 per cubic yard.
RD/R85/025.50
-------
DECLARATION
The selected remedy for this Operable Unit is protective of human
health and the environment, meets Federal and State requirements
that are applicable or relevant and appropriate, and is cost-
effective. This remedy satisfies the preference for treatment
that reduces toxicity, mobility, or volume as a principal
element. All substantive permit requirements will be met during
the implementation of this remedial action. It is determined
that the remedy for this Operable Unit uses permanent solutions
and alternative treatment technologies to the maximum extent
practicable. The Arizona Department of Environmental Quality and
the Arizona Department of Water Resources have concurred with the
remedy presented in this document.
Because this remedy will not result in hazardous substances
remaining onsite above health-based levels, the five-year
facility review will not apply to this action after completion of
the remedial action.
UJ
Date Daniel W. McGovern
Regional Administrator
Region IX
-------
RECORD OF DECISION
CONCURRENCE PAGE
Site: Phoenix-Goodyear Airport Superfund Site, Goodyear,
nrizona
The attached Record of Decision package for the Phoenix- Goodyear
Airport Superfund Site, Goodyear, Arizona, has been reviewed, and
I concur with the contents.
°t
Date
Date
Date
Date
Dat
^
fe
Gail/Cpoper, Acting Regional counsel
Office/ of Regional Counsel
U.S. Environmental Protection
Agency, Region IX
Director
Ha'zardfrtis Waste Management Division
U.S. Environmental Protection
Agency, Region IX
Harry Seraydarian, Director
r Management Division
U.S. Environmental Protection
Agency, Region IX
^^. P. Howakamp, Director
VAir Managementplvision
U.S. Environmental Protection
Agency, Region IX
McGee
Assistant Regional Administrator
Office of Policy and Management
U.S. Environmental Protection
Agency, Region IX
-------
1. SITE DESCRIPTION
The Phoenix-Goodyear Airport (PGA) site covers a total area
of about 35 square miles and is located about 17 miles due
west of Phoenix, Arizona, in the western part of the Salt
River Valley. Figure 1-1 illustrates the site location and
site features. The City of Avondale occupies about 2 square
miles along the eastern border of the site. Except for the
airport, which is owned by the City of Phoenix, the
remainder of the PGA site lies almost entirely within the
City of Goodyear. The remaining land is presently used
primarily for agriculture; however, residential development
west of the airport is anticipated. The general area had a
combined population of about 30,000 people in 1985.
The two major surface-water drainages within the area are
the Gila River to the south and the Agua Fria River to the
east. The Gila River flows perennially due to releases from
treatment plants. The Agua Fria River is dry most of the
year with occasional flows resulting from releases from
dams, irrigation tailwaters, or treatment plants. The Agua
Fria River drains south into the Gila River, which then
flows to the west.
Drinking water supplies, industrial water supplies, and
irrigation water come solely from groundwater that is pumped
from the alluvial deposits of the western Salt River Valley
underlying the entire area.
The site contains the Loral Corporation facility (formerly
owned by Goodyear Aerospace Corporation [GAC]), the Phoenix-
Goodyear Airport (formerly operated by the U.S. Navy), and
UniDynamics Phoenix, Inc. All of these facilities have been
identified as sources of contamination at the PGA site.
Figure 1-2 illustrates the chronology of the major activi-
ties conducted at the PGA site and places in perspective the
timing and relationship between the Section 16 Operable Unit
(OU) Record of Decision and this Record of Decision for the
site as a whole.
A Record of Decision was approved for the Section 16 OU at
the PGA site. The Section 16 OU addressed VOC-contaminated
groundwater in Subunit A within Section 16. This Record of
Decision addresses the vadose zone and remaining groundwater
contamination for the entire site.
The following problem areas were defined during the PGA
RI/FS:
1-1
RD/R85/025.50
-------
1. Vadose zone contamination with VOCs in the vicinity of
the former GAG facility and the Phoenix-Goodyear Air-
port
2. Contamination of the Subunit B/C aquifer south of the
groundwater divide
3o Vadose zone contamination with VOCs at the UPI facil-
ity
4. VOC contamination of Subunit A onsite and downgradient
of the UPI facility
5. VOC contamination of the Subunit B/C aquifer onsite and
downgradient of the UPI facility
6. Limited chromium contamination of soil and groundwater
in the GAG sludge drying beds and adjacent areas
The PGA RI/FS describes these areas and problems in detail.
1-2
RD/R85/025.50
-------
1981 1982 1983
A
I I
I I
1984 1985 1986 1987 1988 1989
ADHS IDENTIFIES
CONTAMINATED
GROUNDWATER
AT GOODYEAR.
ARIZONA
A
PGA IS
PLACED ON
THE NPL
A
UPI INITIATES RI/FS
COMPLETES RI/FS
A
EPA INITIATES RI/FS
A
GAC INITIATES Rl
-A
COMPLETES RI/FS
A
EPA
INITIATES
SECTION 16
OUFS
SECTION 16
OU ROD
SIGNED
A
PGA ROD
SIGNED
(PROPOSED)
JULY 1999
RQURE 1-2
SUMMARY OF MAJOR ACTTVTT1E8
AT PHOENIX GOODYEAR ARPORT
PIIOCNIX OOODYIAR AIRPOKT ROD
-------
CITY OF AVONDALE
LORAL CORPORATION
(FORMERLY QOOOYEAR AEROSPACE CORPORATION)
CITY OF GOODYEAR| |:8
°0
UNIDYNAMICS-PHOENIX INC.
SECTION 16 Is"
» PHOENIX GOODYEAR AIRPORT
GROUNDWATER FLOW DIRECTION
PGA STUDY AREA BOUNDARY
83605.RA AUGUST 1989
FIGURE 1-1
SITE LOCATION MAP
PHOENIX GOODYEAR AIRPORT HOD
-------
2. SITE HISTORY AND BACKGROUND
SITE HISTORY
In 1981, the Arizona Department of Health Services dis-
covered that groundwater in the PGA area was contaminated
with solvents and chromium. Additional sampling of wells in
1982 and 1983 found 18 wells contaminated with trichloroeth-
ylene (TCE). As a result, the EPA added the PGA site to the
National Priorities List in September 1983. In 1984, EPA
began a Remedial Investigation of the Litchfield Airport
Area (presently known as the Phoenix-Goodyear Airport) to
characterize the site, investigate the extent of the con-
tamination, and identify the potential sources.
Historical data indicate activities at three primary
facilities contributed to the groundwater contamination at
the PGA site:
o The former Goodyear Aerospace Corporation (GAG)
facility owned by Goodyear Tire and Rubber,
currently owned by Loral Corporation
o The Litchfield Park Naval Air Facility, currently
the. Phoenix-Goodyear Airport
o UniDynamics Phoenix, Inc. (UPI)
Historical data on waste handling at the former GAC
facility, the airport, and the UPI facility can be found in
the PGA Feasibility Study and the UniDynamics Phoenix, Inc.,
Feasibility Study, respectively.
Sampling data for groundwater identified two major areas of
contamination, a northern area and a southern area.
UniDynamics Phoenix, Inc., operates an industrial facility
north of the former GAC facility across Yuma Road.
UniDynamics Phoenix, Inc., undertook the preparation of a
Remedial Investigation/Feasibility Study (RI/FS) report on
the contamination identified north of Yuma Road and proximal
to its facility. The area south of Yuma Road was
investigated by the EPA, Goodyear Tire and Rubber, and the
Corps of Engineers on behalf of the Department of Defense
and the U.S. Navy. Most of the contamination in the
southern area of the site is concentrated within Section 16.
This Record of Decision covers groundwater, with the
exception of Subunit A water in the south portion, and soil
2-1
RDD\R85\004.50
-------
contamination, with the exception of the chromium-
contaminated soils located in the sludge drying beds at the
former GAG facility. The Goodyear Tire and Rubber Company
is performing an expedited response action under an
Administrative Order on Consent for the chromium sludge
beds.
SITE CHARACTERIZATION
The site is located in a region having a climate charac-
terized by long, hot summers and short, mild winters. Rela-
tive humidity is low, particularly during early summer, and
the rainfall averages about 7.1 inches per year. The aver-
age daily maximum temperature in July is 107°F, the average
daily minimum temperature in January is 34°F, and the aver-
age yearly temperature is 70°F. Temperatures vary between
these extremes throughout the year.
Groundwater is pumped from the alluvial deposits of the
western Salt River Valley. These deposits consist of the
Upper Alluvial Unit, the Middle Fine-Grained Unit, and the
Lower Conglomerate Unit, as shown in Figure 2-1. The Upper
Alluvial Unit has been further subdivided into Subunit A,
from the surface to about 120 feet deep; Subunit B, from
about 120 to 240 feet deep; and Subunit C, from about 240 to
360 feet deep. Subunits A, B, and C are hydraulically
connected.
Most wells in the area pump water from a zone between 100
and 600 feet deep. Depth to the water table has varied in
the past, but recently has been measured between 40 and
100 feet below the ground surface. Groundwater flows in the
PGA area are divided at approximately Yuma Road. The north-
ern area, in the vicinity of UPI, has groundwater flows to
the north or northwest, and the southern area, in the vicin-
ity of the airport and the former GAG facility, has ground-
water flows to the southwest and west.
In addition to the TCE and chromium mentioned earlier,
several other compounds were found to contaminate the
groundwater. Among these are perchloroethylene (PCE),
1,1-dichloroethylene (1,1-DCE), chloroform, and carbon
tetrachloride. Table 2-1 identifies the wells tested,
concentrations detected, and the applicable Federal or State
standards or other criteria. Figures 2-2 through 2-4 show
well locations where organic compounds were detected above
ARAR concentrations at the PGA site. The highest
2-2
RDD\R85\004.50
-------
<
>5
Q
UJ
Z
<~
DC3
(•Jli.
UJ
_l
O
o
On _
>z -'
O •'
o
Rooe
FEET
BELOW
GROUND
SURFACE
UNIDYNAMICS
PHOENIX, INC
GOODYEAR
AEROSPACE CORP
PHOENIX GOODYEAR
MUNICIPAL AIRPORT
>...-o
0°'
;*o
J'«t $^-0 o
3605.RA MAY 1989 RE*VISED JULY 1989
GEOLOGIC CROSS SECTIONS
ARE SIMPLIFIED FOR PRESENTATION.
ACTUAL DEPTHS VARY ACROSS THE SITE.
FIGURE 2-1
SIMPLIFIED NORTH-SOUTH
CROSS SECTIONAL
VIEW OF GEOLOGY
PHOENIX GOODYEAR AIRPORT ROD
-------
Table 2-1
COMPARISON OF THE APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
AND OTHER CRITERIA TO GROUNDWATER DATA
Well/
Station ID
GROUNDWATER
16EMW-1
16EMW-2
16EMW-3
EMW-18B
EMW-18UC
EMW-19B
EMW-I9UC
EMW-19LC
EMW-20B2
EMW-20UC
EMW-20LC
EMW-21UC
EMW-22LC
EMW-27MF
Present
Well Use
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Cotncound
Lead
1 • 1 -Dichloroethy lene
Trichlo roe thy lene
Lead
1 , 1 -Dichloroethy lene
Tr ichlo roe thy lene
Chromium (total)
Lead
Lead
Lead
Lead
Lead
1,2-Dichloro-
propane
Chloroform
Lead
Silver
Lead
Lead
Lead
Lead
Lead
Concentration
(UR/1)
Max-13
Max-9
Avg-<4
Max-75
Avg-33
Max- 14
Avg-7.8
Max- 140
Avg-126
Max-490
Avg-342
Max-513
Avg-472
Max-80
Avg-80
Max-80
Avg-<53
Max-50
Avg-<37
Max- 70
Avg-<47
Max-50
Avg-<37
Max- 1.4
Avg-1.4
Max-3.1
Avg-3.1
Max-80
Avg-<52
Max- 100
Avg-100
Max-60
Avg-<42
Max-50
Avg-<37
Max-50
Avg-<33
Max-50
Avg-<37
Max- 70
Avg-<48
ARARa
Exceeded
MCL, 5 yg/lb
MCL, 7 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 7 yg/1
MCL, 7 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 100 yg/ld
MCL, 100 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 50 yg/1
MCL, 50 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
MCL, 5 yg/1
Other Criteria
Exceeded
ADHS action level1
ADHS action level
ADHS action level
ADHS action level
ADHS action level
ADHS action level
ADHS action level
HAe--longer term/
70 kg, lifetime
HA--longer term/
70 kg, lifetime
ADHS action level
ADHS action level
ADHS action level
ADHS action level
Arsenic"
Max-47
MCL, 5 yg/1
RDD/R76/012.50-1
2-4
-------
Table 2-1
(continued)
Well/
Station ID
EMW-28B
EMW-28UC
EMW-28LC
16GMW-1
16GMW-2
16GMW-3
16GMW-3
9UMW-1,2,3,4
9UMW-4
9UMW-5
Present
Well Use
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Compound
Lead
Lead
Lead
Trichloroethylene
Chromium (total)
Carbon tetrachloride
Methylene chloride
Trichloroethyleae
Lead
1 , 1 -Dichloroethy lene
Carbon tetrachloride
Trichloroethylene
Chromium (total)
Selenium
Trichloroethylene
Total Xylenes
Lead
Methyl ethyl ketone
Trichloroethylene
Lead
Concentration
(UE/1)
Max- 170
Avg-110
Max-90
Avg-<57
Max-90
Avg-80
Max-41.7
Avg-34
Max- 190
Avg-150
Max-5.1
Avg-<2
Max- 13. 2
Avg-<6.8
Max-24.9
Avg-21
Max- 18
Avg-18
Max- 12. 8
Avg-10.8
Max-5.i
Avg-3.5
Max- 155
Avg-102.7
Max- 1,340
Avg-977
Max- 18
Avg-16.7
Max-350,000
Avg-<66,662
Max-8.,800
Avg-8,800
Max- 20
Avg-<7.2
Max- 11, 000
Avg-1 1,000
Max-3.3
Avg-
-------
Table 2-1
(continued)
Well/
Station ID
9UMW-6
9UMW-7,8,9
9UMW-8
9UMW-11
9UMW-12
9UMW-13
9UMW-14
9UMW-15
GAG #2
GAG #3
GAG #3
GAG 14
PLA #2
PLA *3
PLA *4
GF *4A
Present
Well Use
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Monitoring
Industrial
Industrial
Fire
Irrigation
Not in use
Not in use
Irrigation
Comoound
Trichloroethylene
Lead
Trichloroethylene
Methyl ethyl ketone
Lead
Selenium
Lead
Trichloroethylene
1 , 2 -Dichloroethane
Chloroform
Methylene Chloride
Selenium
Lead
Trichloroethylene
Trichloroethylene
Trichloroethylene
Chromium (total)
Trichloroethylene
Trichloroethylene
Trichloroethylene
Arsenic
Trichloroethylene
Concentration
(U2/1)
Max-6.5
Avg-4.2
Max- 10
Avg-<6.3
Max- 140, 000
Avg-23,744
Max-900
Avg-900
Max-60
Avg-45
Max-80
Avg-<52.5
Max-40
Avg-30
Max-450
Avg-<288
Max-2.9
Avg-2.9
Max-5.9
Avg-5.9
Max- 19
Avg-19
Max-80
Avg-<52.5
Max- 20
Avg-<12.5
Max-200
Avg-102
Max- 16
Avg-9.8
Max- 110
Avg-44
Max- 170
Avg-170
Max-4S
Avg-12
Max- 36
Avg-12. 4
Max-310
Avg-256
Max-96
Avg-96
Max-22
Avg-10.5
ARARa
Exceeded
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL
MCL
MCL,
MCL,
MCL,
MCL,
MCL
MCL
MCL,
MCL,
MCL,
MCL,
MCL,
MCL*
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
MCL,
. MCL,
MCL,
MCL,
MCL,
5
5
5
in m
m in
5
5
5
5
5
5
5
5
5
5
5
5
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Other Criteria
Exceeded
ADHS
MCLG
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
action
action
action
action
action
action
action
action
action
action
action
action
action
action
action
action
action
action
action
Level
level
level
level
level
level
level
level
level
level
level
level
level
level
level
level
level
level
level
100 Jlg/1
100 yg/1
5
5
5
5
5
5
5
5
5
5
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
Pg/1
ADHS
ADHS
ADHS
ADHS
ADHS
ADHS
action
action
action
action
action
action
level
level
level
Level
level
level
HA--all categories
ADHS
ADHS
action
action
level
leve 1
RDD/R76/012.50-3
2-6
-------
Table 2-1
(continued)
Well/
Station ID
COG 11,2,3,6
COG HO
COTRIR
DOMES! #3
PHILLIPS
PLUMB
R.WOOD1
R. WOOD 2
R3.6W3.5
RAYNER2
RECMET2
S.SMITH2
SHAWVER
Present
Well Use
Municipal
Municipal
Irrigation
Domestic
Irrigation
Domestic
Irrigation
Irrigation
Irrigation
Irrigation
Industrial
Irrigation
Domestic
Comoound
Lead
Trichloroethylene
Lead
Trichloroethylene
Trlchloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Trichloroethylene
Concentration ARAR8
(ye/1) Exceeded
Max- 2 4
Avg-<13
Max-6.8
Avg-<1.5
Max- 102
Avg-102
Max-4.5
Avg-3.3
Max- 2. 3
Avg-2.3
Max- I 2
Avg-10.3
Max -3
Avg-3
Max -3
Avg-2.5
Max -2
Avg-<1.3
Max- 1.7
Avg-
-------
1A MAY 1989
REVISED AUGUST 1989
FIGURE 2-2
ORGANIC COMPOUNDS ABOVE
ARAR CONCENTRATIONS SUBUNIT A
PHOENIX GOODYEAR AIRPORT ROD
-------
f
I
i
LEGEND
• WELLS SCREENED WITHIN SUBUNIT B
O WELLS SCREENED WITHIN SUBUNIT B
AND OTHER SUBUNITS AND/OR UNITS
1 TRICHLOROETHYLENE
2 1,1-DICHLOROETHYLENE
5 CHLOROFORM
6 CARBON TETRACHLORIDE
RDD63605.RA MAY 1989
FIGURE 2-3
ORGANIC COMPOUNDS ABOVE
ARAR CONCENTRATIONS SUBUNIT B
PHOENIX GOODYEAR AIRPORT ROD
-------
contaminations levels are found in Subunit A, which is the
shallower water-bearing zone, and migrates to the Subunit
B/C zone.
Several organic and inorganic contaminants were detected in
the soils at the site. Chromium, cadmium, aluminum, copper,
TCE, and PCE were detected at concentrations exceeding the
ADHS health-based cleanup levels. Table 2-2 includes the
locations where ADHS levels were exceeded in soil samples.
In addition, concentrations of methyl ethyl ketone and ace-
tone were detected as high as 659 mg/kg and 888 mg/kg,
respectively, in the northern portion of the site.
Table 2-2 also includes contaminants detected in air samples
which exceeded the ADHS guidelines. Carbon tetrachloride,
benzene, TCE, and PCE exceeded the ADHS guidelines in air
samples.
EXPOSURES
ENVIRONMENTAL RECEPTORS
Within the PGA site, there are no unique habitats nor any
threatened or endangered species. Native vegetation at the
site is sparse. However, located immediately south of the
site, the lower Gila River represents the important riparian
habitat in southwestern Arizona. Species that inhabit or
migrate through the area include four federally listed or
endangered species: brown pelican (Pelecanus occidentalis).
Yuma clapper rail (Rallus longirostris vumanensis),
peregrine falcon (Falco peregrinus), and the bald eagle
(Haliaeetus leucocephalus).
The PGA area, particularly near the Gila River, supports
viable hunting populations of mourning dove, white-winged
dove, Gambel's quail, and various waterfowl. The area is
especially popular for dove hunting and is known to support
one of the largest breeding dove colonies in the Southwest.
POPULATION CHARACTERISTICS/RECEPTORS
In 1985, the combined population of the Goodyear and
Avondale area was 30,000. The City of Goodyear has stated
in its general plan that the city expects to grow at a rapid
pace, exceeding 140,000 people within 20 years. However,
this may overestimate actual population growth.
Municipal wells contaminated above Federal and State
standards have been taken out of service. All drinking
2-10
HDD\R85\004.50
-------
, t
I
i
I
LEGEND
• WELLS SCREENED WITHIN SUBUNIT C
O WELLS SCREENED WITHIN SUBUNIT C
AND OTHER SUBUNITS AND/OR UNITS
1 TRICHLOROETHYLENE
2 1,1-DICHLOROETHYLENE
5 CHLOROFORM
6 CARBON TETRACHLORIDE
7 TETRA OR PERCHLOROETHYLENE
RDD63605.RA MAY 1989
FIGURE 2-4
ORGANIC COMPOUNDS ABOVE
ARAR CONCENTRATIONS SUBUNI
PHOENIX GOODYEAR AIRPORT ROD
-------
Table 2-2
COMPARISON OF THE APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
AND OTHER CRITERIA TO SOIL AND AIR DATA
Sanrole No.
SOIL
All Test Pits
All Test Pits
Test Pit 0120
Test Pit 0606
All Test Pits
16-GB-2
16-EP-4
20-EB-6
16-GB-4
AC-2
AC-4
0903
0908
0909
0902
0910
16-GB-l
03A
10A
12B
OlA
Location
Former GAC Sludge
Drying Beds; Back-
ground Sample
Locations
Former GAC Sludge
Drying Beds
Background-
Agricultural
Former GAC Sludge
Drying Bed
Former GAC Sludge
Drying Beds
Former GAC Facility
Airport Drain
Ditch Near
Outfall 001
Marsh Area South
of U.S. 85
Near Former GAC
Sewer line
Airport
Airport
Airport
Airport
Airport
Airport
Airport
Former GAC
Facility
Waste Facility 3,
UniDynamics
Waste Facility 10,
UniDynamics
Waste Facility 12,
UniDynamics
Waste Facility 1,
Compound
Aluminum
Cadmium
Cadmium
Copper
Chromium
Chromium
Aluminum
Aluminum
Copper
TCE
TCE
TCE
TCE
TCE
TCE
TCE
PCE
TCE
TCE
TCE
TCE
Maximum
Concentration ARARa
(mg.ITf.st.) Exceeded
16,410
20.3
1.2
303
29,461
3,400
28,905
24,300
317
1.4
0.46
2.51
0.53
0.338
2.27
0.45
0.150
2.31
1.28
0.937
860
Other Criteri..
Exceeded
ADHS Action Levelb
ADHS Action Level
ADHS Action Level
ADHS Action Level
ADHS Action Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Level
ADHS Cleanup Leve 1
ADHS Cleanup ; •••••- '.
ADHS Cleanup '..*•:- .
04A
UniDynamics
Waste Facility 4,
UniDynamics
TCE
0.415
ADHS Cleanup
. 2-12
RDD/R76/031.50-1
-------
Sample No.
AIR
All Surface/
Breathing Zone
T-0915; Surface
T-0902; Surface
B02; Surface
Location
Table 2-2
(continued)
All Locations
Former GAC
Facility
Former GAC
Facility
Upwind
Compound
Maximum
Concentration
(mR/ka)
Carbon 1.3 yg/m3
Tetra-
chloride;
Benzene 12.8 yg/ra3
PCE
TCE
PCE
2.4 W"3
8.2 yg/m3
3.0 yg/m3
sApplicable or relevant and appropriate requirements.
°ADHS action level=.Arizona Department of Health Services action level.
ARARa
Exceeded
Other Criteria
Exceeded
ADHS Guideline
ADHS Guideline
ADHS Guideline
ADHS Guideline
2-13
RDD/R76/031.50-2
-------
water wells currently in use for municipal supply meet
applicable Federal and State health standards. However,
future population growth will result in greater usage of
groundwater resources, particularly in the contaminated
areas. Use of the groundwater, and development of the sur-
rounding areas, may result in potential exposures to con-
taminants through the means described in Figure 2-5, if no
action is taken at this site and contamination migrates to
areas that contribute to municipal groundwater supply.
TOXICITY
General information describing the toxicity of compounds
identified at the PGA site is provided in the PGA RI/FS.
Compounds discussed here include those that are considered
to be the most significant site contaminants. The general
toxicity characteristics are described for both the organic
and inorganic contaminants.
ORGANIC COMPOUNDS
This group of compounds includes most of the contaminants
identified at the PGA site. Several of these compounds--
carbon tetrachloride, chloroform, 1,1,1-trichloroethane,
PCE, and TCE—may produce liver injury. Carbon tetrachlor-
ide and chloroform have more serious effects on the liver
than TCE and PCE (Doull et al., 1980). Carbon tetrachlor-
ide, chloroform, PCE, and TCE have been classified by the
EPA Carcinogen Assessment Group (CAG) as probable human
carcinogens (Group B2) via ingestion (U.S. EPA, 1989).
Exposures to the above compounds through inhalation may
result in central nervous system depression, including anes-
thesia. Trichloroethylene has been used as an anesthetic
(National Research Council [NRC], 1977). Other effects may
include irritation of the mucous membranes of the nose and
throat and irritation to the eyes (NRC, 1980). Trichloro-
ethylene and PCE are also classified as probable human car-
cinogens by CAG via the inhalation route (U.S. EPA, 1989).
1,1-Dichloroethylene and trans-1,2-dichloroethylene exhibit
similar toxic effects to humans through inhalation and
ingestion exposures. These compounds have anesthetic
properties, and exposures to high concentrations may cause
nausea and vomiting (U.S. EPA, 1985a). The CAG has
classified 1,1-DCE as a possible human carcinogen (Group C)
for both inhalation and ingestion exposure routes (U.S. EPA,
1989).
2-14
RDD\R85\004.50
-------
MEDIA
INTERACTION
MEDIA
DIRECT EXPOSURE PATHWAY
RECEPTOR
z
o
1—
M
F
<
O
Z
0
h-
o
o
z
I
u
Lil
"
GROUNDWATER
GO
O
SOIL
INGESTION BY RESIDENTS WHO USE PRIVATE
WELLS FOR POTABLE WATER SUPPLY
INHALATION OF VOLATILES STRIPPED FROM THE
DRINKING WATER DURING IN-HOME USES SUCH
AS BATHING AND COOKING
DERMAL CONTACT WITH CONTAMINATED
GROUNDWATER FROM RESIDENTS PRIVATE WELLS
-*- INGESTION OF CONTAMINATED SOIL BY ONSITE WORKERS
DERMAL CONTACT WITH CONTAMINATED SOIL BY
ONSITE WORKERS
O
(f>
AIR
INHALATION BY ONSITE WORKERS OF VOLATILES IN
SOIL GAS RELEASED TO THE ATMOSPHERE
KI)n6.36().'j>.RA JULY 198f)
RQURE 2-5
EXPOSURE PATHWAY AND
RECBPTOR SUMMARY
IM-IOCNIX GOODYf AR AIRPORT ROD
-------
INORGANIC COMPOUNDS
This group of compounds includes metals. Some of the inor-
ganic compounds detected at the PGA site, such as chromium,
are much more toxic than others.
Chromium has been identified in some water samples taken
from the site in both the trivalent and hexavalent states.
Chromium compounds in the trivalent (+3) state are of a low
order of toxicity. In the hexavalent (+6) state, chromium
compounds are irritants and corrosive and can enter the body
by ingestion, inhalation, and through the skin (Sittig,
1981). Hexavalent chromium may cause liver and kidney dam-
age, internal bleeding, and respiratory disorders (U.S. EPA,
1985b). Hexavalent chromium has been designated by the GAG
as a human carcinogen (Group A) via the inhalation route
(U.S. EPA, 1989).
RISK
Risk is a function of both exposure and toxicity. At pres-
ent, the exposure to contaminated groundwater is limited,
and the population and environment are not in any immediate
danger. However, future use of contaminated groundwater
will result in increased risks as shown in Table 2-3.
The risk associated with exposures to contaminated
groundwater through drinking water ingestion, particularly
for future use scenarios, is an estimated excess lifetime
cancer risk. The overall future residential risk resulting
from groundwater exposure could be as much as 4 x 10° to 9 x
10"* based on the maximum-reported and average concentrations
of carcinogens detected in groundwater at the site. For the
northern portion of the site, the estimated excess lifetime
cancer risk could go as high as 1 x 10'1 (one excess lifetime
cancer occurrence per 10 people exposed over the course of a
70-year lifetime) based on the maximum reported TCE con-
centration in groundwater at the UniDynamics facility. For
the southern portion of the site, the estimated excess life-
time cancer risk as a result of groundwater ingestion could
go as high as 1 x 10"* (one excess lifetime cancer occurrence
per 10,000 people exposed over the course of a 70-year life-
time) based on the maximum reported TCE concentration in
groundwater. Also for the southern portion of the site, trie
2-16
RDD\R85\004.50
-------
Table 2-3
SUMMARY OF EXPOSURE ROUTES AND RISKS
Medium
Groundwater
Exposure Setting
Residential — Current and
Exposure Risk
Results
Ingest Ion
Potential Uses
Residential--Potential
Use Only
Inhalation
Ingestion
I
h-1
—J
tlfy estimated risks, there is an estimated excess lifetime cancer
o For the Goodyear municipal wells (COG II, 2, 3, and 6) there Is an
estimated excess lifetime cancer risk of 2 x 10 based on the
maximum trlchloroethylene concentration for these wells. There is
no identified Ingestion risk due to noncarclnogens.
o For the private domestic wells PLUMB, SHAWVER, and DOMEST3, the risk
due to trlchloroethylene contamination of these wells can only be
expressed qualitatively because fewer than three samples were
collected from each well. A carcinogenic health risk may be present;
however, the exact nature of the risk cannot be identified. There is
no identified Ingestion risk due to noncarclnogens from these wells.
o The risk from Inhalation of volatlles released from the groundwater
in the course of in-home uses such as cooking, bathing, etc., can.nct
be quantified. However, it should be recognized that this exposure
could contribute to the overall risk from the use of contaminated
groundwater. (
o The estimated excess lifetime cancer risk from Ingestion of ground
water from the Unldynamlcs* monitoring wells presents the most
significant risk values for the site that could be as much as 1 x
10^ based on the maximum concentration of trlchloroethylene.
There is no Identified ingestion risk due to noncarclnogens from these
wells.
o The GAC monitoring wells follow with estimated excess lifetime
cancer risks that could be as high as 2 x 10"' for carbon
tetrachlorlde, 3 x 10"s for chloroform, and 5 x I0"s for trlchloroethy-
lene, all based on the maximum concentration of each constituent
from the three wells. The dally Intake of chromium in groundwater
exceeded the AIC, RfD, and/or A1S value for ingestion exposures
based on concentrations in 16GMW-1 and 16GMW-3. For other non
carcinogens evaluated, there does not appear to be an Ingestion
risk based on the limited available data.
o For the EPA monitoring wells for which 'enough data exist to quanUse
risk that could be as high as 1 x IO"4 for trlchloroethylene, based
on Its maximum concentration, due to exposure through Ingestion of
groundwater. The dally Intake of chromium in groundwater exceeded
the AIC, RfD, and/or A1S value for Ingestion exposures based on con
centratlons In 16EMW-3. For other noncarclnogens evaluated there
does not appear to be an ingestion risk based on the limited avail
able data.
o For EPA Phase II monitoring wells, groundwater data are limited to
two or three sampling rounds; therefore, risks were described qualita-
tively. All of these wells exhibited lead concentrations that
exceeded the current or proposed MCL.
KDD/RHO/OIi.
-------
Table 2-3
(continued)
Medium
Crounduater
(coat'd)
Exposure Setting
Exposure Risk
Results
Air
Occupational—Current and
Potential Uses
Inhalation
I
t-'
CO
o Other wells In the area that presented an estimated excess life-
time cancer risk due to trlchloroethylene include the following:
- CAC #3; 3 X 10~| based on the maximum concentration
CAC #4: 1 X 10 based on the maximum concentration
- PLA 12: 1 X 1(T* based on the maximum concentration
- PLA 13: 1 x 10"* based on the maximum concentration
There was also an estimated excess lifetime cancer risk that could
be as much aa 6 x 10'3 for COG /5 (fire control well) due to the
maximum concentration of arsenic. There is no Identified ingest ion
risk due to noncarclnogens from these wells.
o The risk from inhalation of volatlles released from the groundwater
in the course of in-home uses such as cooking, bathing, etc., cannot
be quantified. However, It should be recognized that this exposure
could contribute to the overall risk from the use of contaminated
groundwater.
o Based on inhalation of volatlles emitted from the onslte soil and
an 8-hour exposure period, the estimated excess lifetime cancer
risk for all compounds with a cancer potency factor for Inhalation
exposures considered could be as much as 1 x 10"° to 2 x 10 .
There is no known inhalation risk as a result of inhalation
exposure to the noncarcinogens considered in the evaluation.
KUU/KHO/OIi.'>o-2
-------
daily intake of chromium in groundwater exceeded the
acceptable intake-chronic, the reference dose, and/or the
acceptable intake-subchronic values for ingestion exposures,
assuming chromium is in the hexavalent species.
The Arizona Department of Water Resources (ADWR) used a
groundwater model to predict the effect on TCE
concentrations based on a number of scenarios under the no
action alternative. These scenarios, or base cases, are:
o Base Case 1—Continued agricultural pumpage at
1985 levels in addition to full implementation of
City of Goodyear proposed wells. Section 16
Operable Unit not incorporated.
o Base Case 2--Pumpage and recharge assumed to
remain constant at 1985 rates over modeling run.
Section 16 Operable Unit incorporated.
o Base Case 3—Phase in City of Goodyear's projected
production wells per the City of Goodyear's Water
Master Plan. Phase out agricultural pumpage and
recharge. Section 16 Operable Unit incorporated.
Trichloroethylene (TCE) concentrations were estimated for
areas adjacent to selected municipal wells using the ADWR
model. Table 2-4 presents the estimated TCE concentrations
and the associated excess lifetime cancer risks as a result
of ingestion of groundwater with the respective TCE
concentration.
The estimated excess lifetime cancer risk as a result of TCE
exposure through ingestion given the assumptions defined
above could be as much as 3 x 10"* for the highest estimated
concentration.
This particular evaluation does not consider the effect of
exposure to other contaminants detected in groundwater at
the PGA site and therefore may underestimate the total risk.
This assessment also only considers exposures through inges-
tion; however, additional exposures may be anticipated
through inhalation of volatiles as a result of in-home uses
of groundwater and exposures through dermal contact with the
contaminated groundwater.
For the southern portion of the site, the inhalation risk to
onsite workers as a result of volatile emissions from soil
could be as much as 1 x ICT4 to 2 x 10-s (8-hour exposure)
based on all volatile compounds detected with a cancer
2-19
RDD\R85\004.50
-------
Table 2-4
ESTIMATED EXCESS LIFETIME CANCER RISK DUE TO TCE EXPOSURE
BASED ON IMPLEMENTING THE NO ACTION ALTERNATIVE*
Well
COS
Base Case 1
TCE Cone.
ID (U8/1)
School
0
Estimated
Excess Base Case 2
Lifetime TCE Cone.
Cancer Riskb (U«/l)
-c 0
District
COG
COG
COG
COG
COG
COG
COG
COG
COG
COG
COG
2
3
8
a
PW
PW
PW
PW
PW
PW
PW
1
2
3
4
5
6
7
<1
0
<1
10.5
0
<1.0
1.7
<1.0
<1.0
3.4
<1.0
<3
<3
3
<3
5
<3
<3
1
<3
x
x
X
X
X
X
X
X
X
10
10
10
10
10
10
10
10
10
•7 <1
o
•7
-------
under the circumstances...." CERCLA Section 121(d)(2).
Applicable or relevant and appropriate requirements (ARARs)
may be waived at the discretion of EPA if criteria set forth
in CERCLA Section 121(d)(4) are met.
For this remedial action, it is appropriate to set cleanup
levels for soils and groundwater. For groundwater, EPA
performed independent analyses of appropriate cleanup level
for Subunit A and Subunit B/C because of different, site-
specific, groundwater quality concerns.
Soils
EPA has identified no chemical-specific ARARs defining
cleanup levels for soils at either the northern or southern
portions of the site. EPA is setting its cleanup level for
soils based on the need to protect human health and the
environment from the contamination of groundwater (both
Subunits A and B/C) which would result without a cleanup of
soils.
EPA's soil cleanup standard for volatile organic compounds
is to remove those contaminants from the soil until EPA is
convinced the levels remaining will not cause or contribute
to the contamination of groundwater in levels in excess of
the cleanup standards for groundwater discussed below. The
volume of contaminants to remain in the soil will be deter-
mined using a decision-tree that was developed by the PGA
Committee members. This decision-tree will be used in the
implementation of the remedial action.
For chromium and other metal contamination in the sludge
pits on the southern portion of the PGA site, EPA will set
final cleanup levels through an administrative order to
Goodyear Tire and Rubber Company. This order will require
Goodyear to remove metals to level sufficient to ensure that
the soils will not be a source of contamination to the
groundwater in excess of the cleanup standards for ground-
water discussed below.
Groundwater
For both Subunits A and B/C of the PGA site, EPA is
establishing cleanup levels as set forth in Table 2-5.
These cleanup levels are to be met throughout the aquifer.
2-21
RDD\R85\004.50
-------
to
I
NJ
KJ
Table 2-5
LEGALLY APPLICABLE
STATE AND FEDERAL REQUIREMENTS AND OTHER CRITERIA
FOR CROUNDWATER
(Concentrations In |lg/l)
Compound
Met
\/Xy]
1,1-Dlchloroethylene
1,2-Dlchloropropane
Chloroform
,., Toluene
^/Trichloroethylene
Trichlorofluoromethane
Carbon Tecrachlorlde
Methylene Chloride
Jthyl Ethyl Ketone
'Xylenes
Anttmony
^Arsenic
Barium
Beryllium
Cadmium
^Chromium
•Lead
Mercury
Nickel
Selenium
Silver
Zinc
Legally
Applicable
SDWA
MCL
7
100
5
5
50
1,000
10
50
50
2
10
50
Other Criteria
AWQC--Drinking Water Only
Toxlclty
15,000
1.46
10
50
50
10
15.4
10
50
5,000
Cancer 10"° Risk
0.033
0.19
2.8
1/0
0.0025
0.0039
ADEQ
Action Level
Water
1
1
3
340
5
1
5
1
170
440
Proposed
MCL
5
200
10,000
5,000
5,000
5
100
5
50
Notes: ADEQ = Arizona Department of Environmental Qua lit)
AWQC = Ambient Water Quality Criteria; adjusted for consumption of
drinking water only; fish ingest Ion component removed (U.S. EPA, 1986).
AWQC (10"*) - The Ambient Water Quality Criteria resulting In a 10"* excess
lifetime cancer risk (U.S. EPA, 1986).
MCL = Maximum Contaminant Level.
MCLC = Maximum Contaminant Level Coal.
SDWA * Safe Drinking Water Act, 40 CFR 141, November 15, 1985.
Source: U.S. EPA, 1987. IRIS Database.
Proposed MCLs - Federal Register, May 22, 1989.
Cleanup
Level
7
1
100
^340
^ 5
1
5
1
170
v/440
1.46
!-"50
I.OC?
0.0039
10
2
15.4
10
50
5,000
-------
Subunit B/C
Subunit B/C is a potential source of drinking water, and
therefore it is relevant and appropriate to use maximum con-
taminant levels (MCLs) set pursuant to the Safe Drinking
Water Act as cleanup levels for contaminants covered by
MCLs. This approach is consistent with Arizona law
(discussed in more detail below) which establishes the MCLs
are to be used as aquifer water quality standards as part of
the process for defining aquifer cleanup levels. Health-
based levels are designed as cleanup levels where they are
more stringent than MCLs or where no MCL exists for a con-
taminant .
Subunit A
Subunit A is not a potential source of drinking water as
defined by the Safe Drinking Water Act and EPA's Groundwater
Protection Strategy because of its elevated levels of total
dissolved solids and nitrates. Because of this, the Safe
Drinking Water Act is not a basis for cleanup levels in
Subunit A. EPA's determination of cleanup levels in Subunit
A is based on the statutory requirement that cleanup levels
protect human health and the environment, RCRA corrective
action requirements, and Arizona cleanup standards. Each of
these criteria result in the cleanup levels in Table 2-5
applying in Subunit A. As discussed below, further
analysis, at least possibly, could result in some modifica-
tion to EPA's determination of cleanup levels based on the
above three criteria. In such event, in setting cleanup
levels, EPA would also consider the statutory preference for
treatment remedies which permanently and significantly
reduce the volume, toxicity, or mobility of contaminants.
Protection of Subunit B/C
The cleanup levels in Table 2-5 for Subunit A are necessary
to prevent the migration of contaminants to Subunit B/C at
levels in excess of health-based levels and ARARs.
UniDynamics, Inc., has contended that higher cleanup levels
could be set for Subunit A while still protecting Subunit
B/C. However, UniDynamics has not, to date, established a
basis for any levels other than those set forth in
Table 2-5. Should EPA determine that other levels are
appropriate to protect Subunit B/C, EPA would consider
revising the cleanup levels in the ROD. However, such a
revision would have to be consistent with EPA's ARARs deter-
minations discussed below.
2-23
RDD\R85\004.50
-------
RCRA Corrective Action
RCRA's corrective action requirements are relevant and
appropriate to setting the cleanup levels for Subunit A.
Pursuant to RCRA and its implementing regulations,
corrective action requires compliance with MCLs established
pursuant to RCRA at the boundary o£ the unit. Where RCRA
MCLs are not available, EPA applies Safe Drinking Water Act
MCLs and health-based limits as the alternate concentration
limit (ACL) for contaminants covered by those MCLs and
health-based limits. In an appropriate case, EPA can allow
different ACLs to apply if EPA determines that the hazardous
constituent will not pose a substantial present or potential
hazard to human health or the environment as long as the ACL
is not exceeded.
As applied to this case, EPA is setting the levels in
Table 2-5 as the ACLs for Subunit A. The point of com-
pliance for these ACLs is the boundary of the locations into
which the contaminants were released; e.g., the boundaries
of the disposal pits, extending vertically through Subunit
Ac These ACLs apply unless EPA determines that the substan-
tive requirements for different ACLs are satisfied. These
substantive requirements are set forth at 40 CFR Section
264.94(b),(c).
Arizona Law
Arizona law establishes a comprehensive scheme for
classifying and protecting aquifers. Portions of this
scheme are relevant and appropriate in defining the cleanup
levels for Subunit A. Under Arizona law, Subunit A is
classified for drinking water protected use, and is subject
to aquifer water quality standards. These standards include
MCLs established pursuant to the Safe Drinking Water Act.
Arizona law also establishes statutory and regulatory
requirements governing the selection of cleanup remedies for
contaminated aquifers. EPA believes that the Arizona
groundwater classification scheme, as applied through the
Arizona statutory and regulatory criteria for selection of
cleanup remedies, is relevant and appropriate to the setting
of cleanup levels.
As applied here, Subunit A is protected for drinking water
uses because it is part of a definable aquifer and has not
received an aquifer exemption. Therefore, Safe Drinking
Water Act MCLs are water quality standards for Subunit A.
Pursuant to Arizona law, cleanups must achieve the maximum
protection of drinking water (i.e., compliance with aquifer
2-24
ROD\R85\004.50
-------
water quality standards) consistent with the other require-
ments for selection of remedial actions.
EPA interprets this requirement here to require the cleanup
of Subunit A to achieve MCLs unless that is not cost-
effective; not reasonable and necessary to prevent, mini-
mize, or mitigate danger to public health or welfare or to
the environment; or inconsistent with other relevant aspects
of Arizona water law. In this case, EPA determines that
complying with MCLs is cost-effective, is reasonable and
necessary to prevent, minimize, or mitigate .danger to public
health, welfare, and the environment, and can.be achieved
consistent with relevant Arizona water law. Therefore, MCLs
are ARARs for Subunit A throughout the subunit, unless
Subunit A qualifies for an aquifer exemption, or EPA has
reason to alter its determination as to whether achieving
such levels is cost-effective, reasonable and necessary, or
achievable consistent with Arizona water law.
2-25
RDD\R85\004.50
-------
3. ENFORCEMENT HISTORY
PHOENIX*GOODYEAR AIRPORT
AND FORMER GAC FACILITY
The responsible parties identified for the PGA site are:
o Goodyear Tire and Rubber Company for activities at
the former Goodyear Aerospace Corporation
facility. The facility has been sold to the Loral
Corporation, who has not been named a responsible
party.
o United States Department of Defense, on behalf of
the United States Navy who operated the Litchfield
Naval Air Base. The Litchfield Naval Air Base was
sold to the City of Phoenix in 1968 and is now the
Phoenix-Goodyear Municipal Airport.
o UniDynamics Phoenix Incorporated for activities at
its facility.
The remedial actions for the south half of the site, the
Phoenix-Goodyear Airport and former GAC facility, will be
the responsibility of the Goodyear Tire and Rubber Company
and the Department of Defense.
Goodyear Tire and Rubber has been participating in the RI/FS
since 1984. Its efforts have been concentrated on
determining the extent of soil contamination at the former
GAC facility and the extent of groundwater contamination
underneath the facility and the airport. A history of EPA
enforcement actions toward Goodyear Tire and Rubber
includes:
o July 23, 1982—RCRA Section 3007/CERCLA Section
104 request for information issued to Goodyear
Tire and Rubber
o March 27, 1984--General notice letter sent to
Goodyear Tire and Rubber from EPA
o March 27, 1984--RCRA Section 3013/CERCLA Section
106 Administrative Order on Consent issued to
Goodyear Tire and Rubber
o December 20, 1984--Violation of the Clean Water
Act issued to Goodyear Tire and Rubber from EPA
3-1
RDD/R52/002.50
-------
o January 14, 1986--Violation of the Clean Water Act
issued to Goodyear Tire and Rubber from EPA
o March 19, 1986--CERCLA Section 106 Administrative
Order on Consent signed by Goodyear Tire and
Rubber and EPA
o April 22, 1987--CERCLA Section 106 Administrative
Order for the implementation of the Section 16
groundwater remedial action—The order was
prepared during negotiation of the Consent Decree
for the remedial action bur was not issued.
o 1987—Sidebar agreement between Goodyear Tire and
Rubber Company and the Department of Defense for
the Section 16 groiradwater remedial action--This
agreement was a result: of the alternative dispute
resolution (ADR) process, and apportioned the
financial contributions of the two responsible
parties.
o 1988—CERCLA Consent Decree between U.S. EPA and
Goodyear Tire and Rubber Company for the Section
16 groundwater remedial action
Between 1945 and 1968, the U.S. Navy operated the Litchfield
Park Naval Air facility adjacent to the GAG facility. The
Navy had sold the Naval Air facility to the City of Phoenix
in 1968 for use as a municipal airport. The U.S. Corps of
Engineers was assigned in May 1985 to represent the
Department of Defense on the Phoenix-Goodyear Airport
Interagency Committee, which was established by EPA to
involve state and local agencies as well as responsible
parties in CERCLA actions at the site.
UNIDYNAMICS PHOENIX. INC.
A history of EPA enforcement actions toward UniDynamics
Phoenix, Inc., includes:
o 1986—RCRA Section 3013/CERCLA Section 106
Administrative Order on Consent was issued to
UniDynamics Phoenix, Inc., from EPA (Docket No.
86-02).
o July 30, 1987—A Supplemental Order was issued to
UniDynamics Phoenix, Inc., from EPA under RCRA
3-2
RDD/R52/002.50
-------
Section'3013 for installation of additional
monitoring wells and collection of soil samples
(Docket No. 86-02).
February 6, 1989--An Order was issued to
UniDynamics Phoenix, Inc., from EPA under CERCLA
Section 106, for submission of an RI/FS report
(Docket No. 89-04).
May 5, 1989—Finding of violation of the terms of
Order 89-04 was issued February 6, 1989.
UniDynamics resubmitted the required deliverables
to correct the deficiencies which caused the
finding of violation.
3-3
RDD/R52/002.50
-------
4. COMMUNITY RELATIONS HISTORY
The following is a list of community relations activities
conducted by the U.S. EPA at the PGA Superfund site (for-
merly the Litchfield Airport Area site):
o EPA conducted interviews with Goodyear and
Avondale residents and State and local officials
in 1984 to improve EPA's understanding of commun-
ity concerns. These interviews provided the basis
for the Phoenix-Litchfield Airport Area Community
Relations Plan released in October 1984.
o EPA established information repositories at the
Avondale Public Library, Phoenix Public Library,
and the Arizona Department of Health Services.
EPA updated repositories periodically with fact-
sheets and other relevant documents.
o EPA established a computerized mailing list with
over 200 addresses of interested individuals.
o EPA contributed PGA-related information to
Groundwater Quality Update, a newsletter that pro-
vides information about groundwater quality to
interested parties, prepared and distributed by
the Arizona Department of Health Services.
o EPA distributed a factsheet in July 1984 which
provided an overview of the Superfund process,
gave a brief description of the PGA site con-
tamination, and described proposed remedial
investigation/feasibility study (RI/FS)
activities.
o EPA held a community meeting on August 1, 1984, to
provide an overview of the Superfund process and
information on past site activities and outline
future RI/FS activities.
o EPA distributed an "Update on Site Activities"
factsheet in February 1985 which described ongoing
RI/FS activities including water level measurement
and water quality sampling, soil boring and samp-
ling, well installation, and computer modeling.
o EPA released the "Water and Soil Sample Results"
factsheet in June 1985 which reported the results
4-1
RDD/R52/002.50
-------
of the soil and water sampling, and discussed how
this information would be used in the second phase
of the RI/FS.
EPA held a community meeting on February 19, 1986,
to report the Remedial Investigation (RI) Phase I
results, and to discuss the additional information
needed to complete the RI and the plan for obtain-
ing this information during the upcoming RI Phase
II activities.
EPA sent out a factsheet in January 1987 which
provided groundwater sampling results and dis-
cussed the Operable Unit Feasibility Study (OUFS).
EPA distributed a factsheet in May 1987 announcing
the release of the OUFS and the beginning of a
public comment period for the study, as well as
announcing a community meeting on June 4, 1987.
EPA held a public comment period from June 2,
1987, to July 2, 1987, on the draft OUFS and pre-
pared a responsiveness summary to address the com-
ments received.
EPA announced the public comment period on the
draft OUFS and the public meeting with a public
notice placed in Goodyear's weekly newspaper
Westsider which ran on Thursday, May 28, 1987, and
Thursday, June 4, 1987.
EPA distributed a factsheet in October 1987,
describing the treatment system proposed for the
Section 16 OU.
EPA distributed a factsheet in December 1988
updating the public on site-related activities.
The factsheet included the terms of the agreement
finalised with Goodyear Tire and Rubber, the
Department of Defense, and EPA concerning cleanup
activities for the Section 16 OU.
EPA distributed a factsheet in May 1989 announcing
the release of the Feasibility Study and preferred
remedy for public comment.
EPA held a public meeting on June 21, 1989, to
solicit public input on the RI/FS and preferred
remedy.
4-2
RDD/R52/002.50
-------
o EPA held a public comment period on the RI/FS
report from June 7 to July 7, 1989. A response
summary to address the comments received is
included as Appendix B of this ROD.
In addition, EPA will continue to conduct ongoing community
relations activities at the PGA site throughout the duration
of the remedial action.
4-3
RDD/R52/002.50
-------
5. ALTERNATIVES EVALUATION
A range of remedial action alternatives were evaluated for
the volatile organic compound (VOC)-contaminated vadose zone
and groundwater in Subunit B/C and Subunit A outside of
Section 16 in the northern portion of the site.
Alternatives were evaluated based on their ability to meet
the remedial response objectives.
PHOENIX-GOODYEAR AIRPORT
AND THE FORMER GAG FACILITY
The soil and vadose zone investigations identified two prob-
lem areas:
o VOC-contaminated soils on the Phoenix-Goodyear
Airport and former Goodyear Aerospace Corporation
(GAC) facility
o Contaminated soils associated with the former
chromium sludge beds
Chromium-contaminated soils were not considered in this
evaluation since Goodyear Tire and Rubber will perform the
remedial action for the chromium-contaminated soil under an
Administrative Order on Consent.
A wide range of technologies was identified for VOC-
contaminated soil. The remedial response objectives for
contaminated soil are to:
o Protect public health and the environment from
exposure to VOC-contaminated soil
o Prevent migration of VOCs that would result in
concentrations in the groundwater exceeding the
requirements of the Section 16 Record of Decision
and the requirements of this sitewide Record of
Decision
The areas of groundwater contamination have been identified
as the following:
o Subunit A plume of TCE and 1,1-dichloroethylene
(1,1-DCE). This problem is being addressed in an
expedited fashion as the Section 16 Operable Unit.
The Operable Unit remedy is consistent with and
5-1
RDD\R225\027.50
-------
part of the final remedy proposed in this Record
of Decision.
o Subunit B/C near the former GAG facility and the
airport with TCE above ARARs. This includes some
City of Goodyear wells.
o Subunit B/C west of the airport with TCE in pro-
duction wells. One well in particular, the
Phillips well, has exhibited TCE concentrations
above ARARs.
For groundwater, the technologies were screened on their
ability to satisfy the media-specific remedial response
objectives:
o Protect public health and the environment from
exposure to contaminated groundwater
o Eliminate further migration of contaminated
groundwater
o Restore the quality of the Subunit B/C aquifer
with respect to contaminant levels that can be
attributed to industrial activities
SOILS
Listing of Alternatives
The soil alternatives for remedial action are:
o Excavation and treatment
o Placement of a RCRA-type multilayer clay and mem-
brane cap and/or an asphaltic concrete cap over
contaminated soils
o In-place treatment by soil vapor extraction
o No action
These alternatives were evaluated for their cost-effective-
ness in meeting the remedial response objectives. A range
of action levels, determined through analyzing the
applicable and relevant or appropriate requirements, was
also evaluated for three areas delineated by the level of
soil contamination. These target areas are depicted in Fig-
ures 5-1 through 5-3.
5-2
HDD\R225\027.50
-------
RA MAV 1909
FIGURE 5-1
TARGET AREA 1
FOR SOILS REMEDIAL ACTION
AT PHOENIX GOODYEAR AIRPOR
AND FORMER GAC FACILITIES
PHOENIX GOOPYEAR AIRPORT ROD
-------
100 400 FEET
FIGURE 5-2
TARGET AREA 2
FOR SOILS REMEDIAL ACTION
AT PHOENIX GOODYEAR AIRPORT
AND FORMER GAC FACILITIES
PHOENIX GOODYEAR AIRPORT ROD
-------
FIGURE 5-3
TARGET AREA 3
FOR SOILS REMEDIAL ACTION
AT PHOENIX GOODYEAR AIRPORT
AND FORMER GAC FACILITIES
PHOENIX OOOOYEAR AIRPORT HOD
-------
Screening of Alternatives
As set forth by CERCLA and SARA, remedial actions are those
responses to releases that are consistent with a permanent
remedy to prevent or minimize the release of hazardous
substances, pollutants, or contaminants so they do not
migrate to cause substantial danger to present or future
public health or welfare or the environment. SARA, Sec-
tion 121, requires consideration of the following criteria
when evaluating alternatives:
o Protectiveness of human health and the environment
o Attainment of Federal and State public health and
environmental requirements
o Cost-effectiveness
o Utilization of permanent solutions through reduc-
tions in volume, toxicity, or mobility of the haz-
ardous substances, pollutants, and contaminants
o Community acceptance
o Short-term effectiveness
o Long-term effectiveness
o Implementability
o State acceptance
SARA also mandates that the offsite transport and disposal
of hazardous substances or contaminated materials without
such treatment should be the least favored alternative reme-
dial action where practicable treatment technologies are
available.
Alternatives were screened based on their ability to meet
the above-stated requirements and to meet the rer.adial
response objectives for each media.
Three remedial action alternatives concerning VOC con-
tamination in vadose zone soils at the Phoenix-Goodyear
Airport and former GAC facilities were selected for further
evaluation:
5-9
RDD\R225\027.50
-------
o Placement of a RCRA-type clay and membrane cap
and/or an asphaltic concrete cap over contaminated
soils
o In-place treatment by soil vapor extraction
equipped with emission control devices
o No action
Capping. The following two areas were considered for place-
ment of asphalt and RCRA-type multilayer caps at the airport
and former GAC facilities:
o Area delineated by soil sampling results indicat-
ing elevated VOC concentrations in site soils
(corresponds to Target Area 2; see Figure 5-4)
o Area delineated by soil gas sampling results
indicating elevated VOC concentrations in soil gas
(corresponds to Target Area 3; see Figure 5-5)
Table 5-1 presents the estimated areal quantities requiring
capping based on analyses of soil gas and samples of soil at
the airport and former GAC facilities.
Table 5-1
ESTIMATED CAPPING AREAS
Total area considered for capping
Estimated ara<* occupied by existing
buildings
Estimated area considered covered
adequately by existing asphalt
and concrete
Area Derived from
Soil Sample Analyses
Shoving VOC Levels
Greater than Background
(square yards)
284,100
63,000
11,800
Area Derived from
Soil Gas Analyses
(square yards)
636,000
147,100
146,500
Estimated total area considered
acceptably covered
Estimated r«»ma-tning area requiring
coverage
Estimated area of asphalt cap
required
Estimated area of RCRA-type
multilayer clay-membrane cap
74,800
209,300
204,700
4,600
293,600
342,400
300,500
41,900
5-10
RDD\R225\027.50
-------
I EG END
I IUITS Of CA-TIM-; AREA
Cl*v MFMflflANE CAPPING OPTION
- - ESTIMATED AREAS Of TCE CONTAMINATION
F- '-'I AHFA COVERED BY EXlSTINQ ASPHALT
OR CONCREII PAVINQ
FIGURE 5-4
CAPPING ALTERNATIVE AREA
DELINEATED BY
SOIL SAMPLING ANALYSES
AT PHOENIX GOODYEAR AIRPORT
AND FORMER GAC FACILITIES
PHOENIX QOOOYE'R AIRPORT ROD
-------
LEGEND
LIMITS OF CAPPING AREA
• • CLAY-MEMBRANE CAPPING OPTION
I. -1 AREA COVERED BY EXISTING
ASPHALT OR CONCRETE PAVING,
FIGURE 5-5
CAPPING ALTERNATIVE AREA
DELINEATED BY ELEVATED SOIL
AT PHOENIX GOODYEAR AIRPOR1
AND FORMER GAG FACILITIES
PHOENIX OOODVEAR AIRPORT ROD
-------
BUILDING NUMBER
• SOIL BORING
e SOIL VAPOR EXTRACTION WELL
o AIR INLET WELL
FIGURE 5-7
TARGET AREAS A, B, AND C
FOR SOILS REMEDIAL ACTION
AT UNIDYNAMICS
PHOENIX GOODYEAR AIRPORT ROD
IDU63BOS.RA AUGUST HID!)
-------
Table 5-18
TECHNICAL FEASIBILITY SCREENING OF TECHNOLOGIES
AND PROCESSES FOR THE SOILS OBJECTIVE
cn
I
General Response Action
No Action
No Action
Containment
Containment to minimize
migration of contami-
nants into groundwater
Technology
Process
Collection and Onsite
Treatment
Collection of volatiles
Treatment of volatiles
Monitoring,
institutional
controls
Capping
Soil vacuum
extraction
Physical treatment
Thermal treatment
Soil cap
Soil cap with synthetic
membrane
Asphalt cap
Concrete cap
Soil vacuum
extraction
Carbon adsorption
Incineration, catalytic
incineration
Feasibility Screening Comments
Required by NCP
Potentially feasible
Potentially feasible
Potentially feasible
Potentially feasible
Potentially feasible
Potentially feasible
Not feasible, inefficient for
low (ppm) concentrations of
organics. Poor for chlori-
nated organics, requires fur-
ther treatment.
-------
Ul
I
Ul
CO
Table 5-18
(Continued)
General Response Action
Partial Removal and
Treatment/Disposal
Partial removal and
offsite disposal of
contaminated soils
Partial removal and
onsite treatment and
disposal of contaminated
soil
Technology
Process
Feasibility Screening Comments
Excavation
Transport
Hazardous waste
disposal facility
Excavation
Drilled excavation
Transportation equipment
Incineration
Potentially feasible
Potentially feasible
Potentially feasible
Potentially feasible
-------
Table 5-19
SOILS REMEDIAL ACTIONS—COST SUMMARY
OiM Total
Alternative Target Capital Cost Annual OiM Present Worth Present Worth
Technology Area (S) Cost (S) 5 Percent 5 Percent
Soil Vapor
Extraction
Target
Area A
Target
Area B
Target
Area C
529,700
1,051,200
1,051,200
75,000
110,000
110,000
299,500
516,600
516,600
829,200
1,567,800
1,567,800
Evaluation of Alternatives. The summary of the technical
evaluation for the remedial action alternatives for VOC
soils contamination in the vadose zone is presented in
Table 5-20. Target Areas B and C overlap; consequently,
these target areas were combined in the evaluation.
Although not presented, excavation may be required for MEK-
and acetone-contaminated soils. Additional field
investigation will be conducted during and after soils
remedial actions to determine the extent of MEK and acetone-
contaminated soils requiring excavation and treatment.
GROUNDWATER
Listing of Alternatives
A wide range of alternatives was identified for the UPI por-
tion of the PGA site. The general process and technology
options were identified in part based on their potential
application to the specific objectives for groundwater at
the UPI site. These remedial response actions were:
o No action
o Limited action
o Containment
o Pumping and onsite treatment
Initial screening of the technologies and process options
was based on technical implementability or feasibility.
Entire technologies and individual process options were el-
iminated from further consideration if they could not be
implemented because of physical constraints at the site,
chemical characteristics, or if their implementation.could
potentially result in a greater risk to human health and the
environment than presently exists.
5-59
RDD\R225\027.50
-------
Five groundwater target volumes were evaluated for each
alternative:
o Capture and treatment of TCE in Subunit A that
exceeds 100 ppb
o Capture and treatment of TCE in Subunit A that
exceeds Maximum Contaminant Levels (MCLs)
o Capture and treatment of TCE in Subunit A that
exceeds background concentrations
o Capture and treatment of TCE in Subunit C that
exceeds MCLs
o Capture and treatment of TCE in Subunit C that
exceeds background
Groundwater options were combined to give a range of manage-
ment and treatment options consistent with the groundwater
objectives. Table 5-21 presents a summary of the technical
feasibility of technologies and processes for the ground-
water quality objective. The groundwater options were
assembled from representative processes as follows:
1. No action
2. Groundwater extraction from Subunit A, treatment
that exceeds MCLs by air stripping with vapor
phase carbon, granular activated carbon polishing,
and reinjection to Subunit A
3. Groundwater extraction from Subunit A at a higher
rate than Option 2, treatment that exceeds back-
ground concentrations by air stripping with vapor
phase carbon, granular activated carbon polishing,
and discharge to Subunit A by reinjection
4. Groundwater extraction from Subunit C, treatment
that exceeds MCLs by air stripping, granular
activated carbon polishing, and discharge to Sub-
unit C by reinjection or incorporation of treated
water into the potable water supply
5-60
RDD\R225\027.50
-------
Table 5-20
EVALUATION OF SOIL OPTIONS
Excavation
TarRct Area A
Details of Option*
Ul
I
gomrounltv Acceptance
Short -term
Effectlveness
ProtectIvenesa
Excavation of aoll at Waate
Facility Ro. 1 and Solvent
Collection Areae A, B, and C,
where aaaple an*ly*ee are
greater than ADHS draft aoll
action levela.
Treatment of contaminated aolla
onalte via the uee of rotary
kiln..
Import of aoll for backfill of
excavated areaa.
Unknown.
Short-term environmental
impact* via contaminated duat
problems nay be difficult to
control.
Construction complete within 1
year.
Contaminated aoll renoved and
treated with 1 year.
Workera would need to be
protected during construction
and Implementation.
Excavation
Target Areas • » C
Excavation of aoll within
Target Area A plus
excavation at Solvent
Collection Area DI Waste
Facility Ho. 4| Waate
Facility No. I0| and
Waate Facility No. I2f
where aample analyaes are
greater than background
and/or soil gaa 1*
greater than 1 |lg/l.
Treatment of
contalmlnated aolla
onalte via the use of
rotary kilns.
Import of soil for
backfill of excavated
areaa.
Unknown.
Short-term environmental
Lmpacta via contaminated
duat problems may be
difficult to control.
Construction complete
within 1 year.
Contaminated soil removed
and treated within I
year.
Workers would need to be
protected during
construction and
Implementation.
SVE Target Area A
Inatallatlon at SVE
network in Target Area A
where sample analyaes are
greater than ADHS draft
aoll action levela.
Treatment by aoll vacuun
extraction and vapor
phaae carbon.
Unknown.
Short-term environmental
impact* are minimal.
Construction complete
within 6 months.
Soil contamination
remediated in
approximately 3 to 5
yeara.
Workers are protected
during construction and
implementation.
SVE Target Areaa B 4 C
Installation of SVE network in
Target Area* B I C where
•ample analyaea are greater
than background and/or 1 Pg/l
•oil gaa.
Treatment by aoll vacuum and
vapor phaae carbon in southern
two areaa only.
Unknown.
Short-term environmental
impact* safety Issues In Areaa
B t C.
Construction complete within 6
months.
Soil contamination remediated
in approximately 3 to 5 yeara.
Workera are protected during
construction and
implementation.
RI)D\R82\038.50-1
-------
Table 5-20
(Continued)
ExcavalIon
Target Area A
Implementability
NJ
Conventional excavation
equipment and methodology.
Would require tie-back wall at
Solvent Collection Areaa A, 9
and C.
Safety procedure* would be
difficult to Implement.
Adequate work force and
equipment available.
Difficult to Implement without
moderate disruption t> facility
activities.
Reduction of
Toxicity, Nobility,
or Volume
Soil excavation to reduce
nobility or nlgretlon of
contaalnanta within aoil.
Reduce* toxicity and volume of
contaminated aoll by treatment
using onalte Incineration.
Excavat ion
Target Areaa B 4 C
Conventional excavation
equipment and
methodology.
Would require tie-back
wall at Solvent
Collection Areaa A, B and
C.
Would require some
demolition and facility
relocation.
Hay require disruption of
certain explosive and
propelisnt operations.
Safety procedurea would
be difficult to
implement.
Adequate work force and
equipment available.
Difficult to implement
without severe disruption
to facility activities.
Soil excavation to reduce
mobility or migration of
contaminant* within aoil.
Reduces toxicity and
volume of contaminated
aoll by treatment using
onsite incineration.
SVE Target Area A
Conventional technology
for aoil vacuum
extraction, collection,
and treatwent.
Hay require disruption of
certain explosive and
propellent operations.
Adequate work force and
equipment available.
Moderate disruption to
facility activities.
Require* periodic
Monitoring.
SVE treatment uaea
collection by aoll vacuum
extraction to reduce
nobility of contaminant*.
Reduce* toxicity and
volume of contaminant* by
activated carbon
treatment.
SVE Target Area* B » C
Conventional technology for
•oil vacuum extraction,
collection, and treatment.
Hay require disruption of
certain explosive and
propellent operation*.
Adequate work force and
equipment available.
Severe disruption to facility
activIt lea.
Safety requirement* may be
difficult to Implement.
Require* periodic monitoring.
SVE treatment uaea collection
by aoll vacuum extraction to
reduce mobility of
contaminanta.
Reduce* toxicity and volume of
contaminants by activated
carbon treatment.
KI>U\Ra2l018.SO-2
-------
Table 5-20
(Continued)
Excavation
Target Area A
Reduct Ion of
Toxlclty. Nobility,
ot Volume
(Continued)
cn
I
Overall Piotectton
of Human Health and
the Environment
Reduce* toxlclly and volume of
reatdual contaminant a by
dlapoaal at a TSO facility.
A calculated 23,700 pounda of
TCE and other volatile organlca
currently estimated to be
preaent la to be removed from
the excavated areaa In 2 yeara.
May Increaae VOC contamination
In atctoaphere via fugitive duat
problema.
Hay Increase ahort-terra
expoaure of comnunlty and
workers via atmospheric
tranaport of VOCa.
Short-term rlaka are high with
potential for atmospheric
contamination by VOCa In duat.
Risk* are reduced, and long-
tern permanent effectlveneaa la
achieved. llowever, target
levela may be In exceaa of
required level of cleanup. To
that extent there would be no
further rlak reductIon.
Excavation
Target Areaa B » C
Reduces toxlclty and
volume of residual
contaminants by disposal
ai a TSO facility.
A calculated 23,200
pounds of TCE and other
volatIle organlca
currently estimated to be
present la to be removed
from the excavated areaa
In 2 ysara.
Hay Increase VOC
contamination la
atmosphere via fugitive
dual problems.
Hay Increase short-term
expoaure of comnunlty and
workers via atmospheric
transport of VOCa.
Short-term risks are high
with potential for
atmospheric contamination
by VOCa tn duac.
Rlaka are reduced, and
long-term permanent
effectIveneaa la
achieved. However,
target levela may be In
exceea of required level
of cleanup. To that
extent there would be no
further risk reduction.
SVE Target Area A
SVE TarRet Areas BIG
Up to the calculated
23,200 pounda of TCE and
other volatile organlca
currently estimated to be
preaent would be removed
frosi the soil over a
S-year treatment period.
Short-tern rlaka are low
with relatively short
Implementation times for
treatment and protection
of community and workers.
Rlska are reduced, and
long-tern permanent
effectiveness la
achieved. However,
target levela nay be In
exceaa of required level
of cleanup. To that
extent there would be no
further rlak reduction.
Up to the calculated 23,200
pounda of TCE and other
volatile organlca currently
estimated to be present would
be removed from the aoll over
a S-year treatment period.
Short-term risks are low with
relatively short
Implementation tiroes for
treatment and protection of
comnunlty and workera.
Rlaka are reduced, and long-
term permanent effectiveness
la achieved. However, target
levela may be In exceaa of
required level of cleanup. To
that extent there would be no
further rlak reduction.
Rnn\R82\03B.€)0-1
-------
Table 5-20
(Continued)
EicavatIon
Target Area A
Overall Protection
of Human Health and
the Environment
(Continued)
State Acceptance
COSTS
Capital Coata
Annual Coata
Preaent Worth Coata
Long-term
EffectIveneaa and
Permanence
Ul
I
Doea not conform to preference
for avoiding land dlapoaal.
There are no ARARa for aoll
cleanup.
Approval fron agenclea
uncertain.
$21.776,SCO
$21,7/6,500
No risk remain! at concluaion
of rcMdlal activities.
Conventional technology with
proven reaulta.
ExcavalIon
Target Area* B fc C
Doea not conform to
preference for avoiding
land dlapoaal.
There are no ARARa for
aoll cleanup.
Approval from agenciea
uncertain.
$40,326,150
$40,328,150
No riak remalna at
concluaion of remedial
actlvltlea.
Conventional technology
with proven reaulta.
SVE Target Area A
There are no ARARa for
aoll cleanup.
Approval froai agenclea
uncertain.
$539,700
$ 75,000
$829,200
No riak remalna at
concluaion of remedial
actlvitlea.
Conventional technology
with proven reaulta.
SVE Target Areaa B t. C
There are no ARARa for aoll
cleanup.
Approval from agenclea
uncertain.
$2,102,400
$ 220,000
$3,135,600
No riak remalna at concluaion
of remedial activities.
Conventional technology with
proven reaulta.
HI>l)\HB2\01B.iO 4
-------
Table 5-21
TECHNICAL FEASIBILITY SCREENING OF TECHNOLOGIES
AND PROCESSES FOR THE GHOUNDWATER QUALITY OBJECTIVE
General Response Action
No Action
No Action
Technology
Monitoring
Process
Monitoring, institutional
controls
Feasibility Screening Comments
Required by NCP
en
I
cr>
en
Limited Action
Containment
Containment to prevent
migration of contami-
nated groundwater
Point of use wellhead Treatment at drinking water Potentially feasible
production wells
Vertical barrier
Slurry wall
Steel sheet pile wall
Grout wall
Potentially feasible
Not feasible for depths
required
Not feasible for depths
required
Pumping and Onsite
Treatment at a Central
Treatment Facility
Pumping, onsite treat-
ment and discharge
Groundwater pumping
Physical-chemical
treatment
Production wells
Air stripping
Steam stripping
Carbon adsorption
Reverse osmosis, ion
exchange, vapor compression
evaporation
Potentially feasible
Potentially feasible
Potentially feasible
Potentially feasible
Not feasible for organics;
potentially feasible for
inorganics
-------
Table 5-21
(Continued)
General Response Action
Pumping and Onsite
Treatment at a Central
Treatment Facility
(continued)
Technology
Process
Feasibility Screening Comments
t/i
I
en
UV-oxidation
Bioloyical treatment Biological treatment
In situ treatment Enhanced bioreclamation
Chemical oxidation
Discharge
uischarge to aquifer Injection wells
Discharge to surface
water
Discharge to irriga-
tion canal system
Uischarge to
industrial user
Discharge to sewer
(iJUTW)
Spreading basins
Transmission system
Transmission system
Transmission system
Transmission system
Potentially feasible
Not feasible; incompatible for
waste types encountered
Not feasible; incompatible for
chlorinated organics
Not feasible; undemonstrated
with potential for adverse
effects
Potentially feasible; poten-
tial clogging problems due to
water quality
Potentially feasible
&
Potentially feasible
Potentially feasible; seasonal
use of water
Potentially feasible; limited
by demand
Potentially feasible; limited
capacity of current POTW to
receive discharge
-------
Table 5-21
(Continued)
General Response Action
Pumping and Onsite
Treatment at a Central
Treatment Facility
(continued)
Technology
Process
Feasibility Screening Comments
Discharge to potable
water system
Transmission system
Potentially feasible; limited
by demand and capacity of
current water supply system to
receive discharge
Ul
I
RUD/R15/022
-------
5. Ground-water extraction from Subunit C at a higher
rate than Option 4, treatment that exceeds back-
ground by air stripping, granular activated carbon
polishing, and discharge to Subunit C by reinjac-
tion or incorporation of treated water into the
potable water supply
Three options were considered for the removal of MEK from
Subunit A groundwater:
o Ultraviolet/ozone
o Steam stripping, vacuum steam stripping
o Hot air stripping
The technology evaluation process examined a number of
extraction, treatment, and end use alternatives. These are
discussed in the Unidynamics Feasibility Study, Chapter 4,
and the EPA September 7, 1989, memo listed in the
Administrative Record Index (Appendix A).
Screening of Alternatives
The groundwater options were screened based on the require-
ments outlined in SARA and CERCLA and based on effective-
ness, implementability, and cost. Comparative analyses were
performed so that options that may be unprotective, ineffec-
tive, difficult to implement, or excessively costly would be
screened from the list of potentially viable options and
dropped from further consideration.
Based on this rationale, two alternatives were eliminated:
o Ultraviolet/ozone treatment for MEK removal
o Steam stripping, vacuum steam stripping for MEK
removal
The summary of the technical evaluation for the remedial
action alternatives for groundwater contaminated by VOCs is
presented in Table 5-22.
EVALUATION OF ALTERNATIVES
The evaluation of alternatives was undertaken to provide the
information needed to select an appropriate action that pro-
tects human health and the environment and is cost-effec-
tive. The evaluation was performed within the statutory and
policy framework mandated by CERCLA and SARA. The evalua-
tion of the various alternatives was based on the following
factors:
5-68
RDD\R225\027.50
-------
o Technical considerations of the hydrogeologic set-
ting
o Beneficial use of groundwater
o Uncertainties in the fate and transport of TCE in
the groundwater flow system
o Results of the Endangerment Assessment regarding
public health and the environment
o ARARs and other institutional programs
o Effectiveness in meeting remedial action objec-
tives, implementability, and cost-effectiveness
A summary of the detailed analysis of groundwater alterna-
tives is presented in Table 5-23. Detailed costs are
presented in Table 5-24.
No Action Alternative. The no action alternative would
allow the groundwater contamination to spread over an ever-
widening area and would likely have continuing adverse
environmental and health consequences. These include
exposure to carcinogens and other harmful contaminants
through ingestion of water and soil and inhalation of soil
gas released from pumped groundwater.
Extraction/Treatment Alternatives. The pumping alternatives
for both Subunit A and C accomplish the objective of stop-
ping migration of contaminants at the UPI site. When
coupled with treatment, they also reduce the volume, mobil-
ity, and toxicity of the groundwater contaminants. Pumping
to extract contaminated groundwater would prevent migration
of contaminants from the chosen pumping area. This technol-
ogy has been demonstrated to be successful in other areas.
Aquifer rehabilitation estimations are based on hydrogeo-
logic principles and regional flow characteristics; conse-
quently, the rate of extraction will impact the time
required for rehabilitation. Analysis of water samples from
monitoring wells for contaminant levels will indicate
aquifer cleanup. Operation is relatively simple and is not
expected to significantly affect the alternative's reliabil-
ity. It is likely that during the remedial action, some
components will require maintenance or replacement. No
impediments to well construction are foreseen; however,
safety hazards may be present during construction. These
5-69
RDD\R225\027.50
-------
Table 5-22
SUMMARY OF THE SCREENIWJ OF
CROUNDWATER AQUIFER REMEDIAL ACTIONS
Alternative
--J
O
1. No Action
2. Croundwater extraction from the area In
Subunlt A above 100 ppb TCE. Treatment by
alr-atrlpplng with vapor phaae carbon and
relnjecclon to Subunlt A.
3. Croundwater extraction from Subunit A
treatment that exceeda ARARs by air
stripping with vapor phaae carbon,
granular activated carbon pollahlng,
and relnjectlon to Subunlt A.
4. Croundwater extraction from Subunlt A at •
higher rate than Option 3, treatment that
exceeda background by air (tripping with
vapor phaae carbon, granular activated
carbon pollahlng, and relnjectlon to
Subunlt A.
5. Croundwater extraction from Subunlt C,
treatment that exceeda ARARa by air
•tripping, granular activated carbon
pollahlng, and discharge to Subunlt C by
relnjectlon or incorporation of treated
water Into the potable water aupply.
Groundwater extraction from Subunlt C
at a higher rate than Option 5, treatment
that exceeds background by air stripping
and granular activated carbon pollahlng,
discharge to Subuntt C by relnjectlon or
Incorporation of treated water Into the
potable water eiiply.
Iroplementablllty
N/A
A groundwater extraction,
treatment, and relnjectlon system
would be relatively eaay to
conatruct and Implement.
A groundwater extraction, treat-
ment, and relnjectlon ayatem
would be relatively eaay to
conatruct and Implement.
A groundwater extraction, treat-
ment, and relnjectlon ayatem
would be relatively eaay to
conatruct and Implement.
A groundwater extraction, treat-
ment, and relnjectlon or dis-
tribution ayatem would be
relatively eaay to conatruct and
Implement. Community opposition
may prohibit Introduction of
treated groundwater into potable
aupply.
A groundwater extraction, treat-
ment, and relnjectlon or dis-
tribution aystem would be
relatively easy to conatruct and
Implement. Cumunlty opposition
may prohibit Introduction of
treated groundwater Into potable
aupply.
Effectiveness
N/A
The ability of the system to
extract contamlnanta la fairly
certain. The duration of the
action la estimated at 20
yeara.
The ability of the ayatem to
extract contaminants la fairly
certain. The duration of the
action ia estimated at 25
yeara.
The ability of the aystem to
extract contaminants la fairly
certain. The duration of the
action la estimated at 17
yeara.
The ability of the aystem to
extract contaminants la fairly
certain. The duration of the
action la estimated at 25
yeara.
The ability of the ayatem to
extract contamlnanta ia fairly
certain. The duration of the
action ia estimated at 25
yeara.
Relative Cost
Low
Medium
Medium to High
High
Low
Low
RI)U\R82\OJ7.bO-l
-------
Table S-22
(Continued)
Alternative
7. Ultraviolet/ozone treatment for HER
removal.
liBpelement ability
8.
Stean (tripping, vacuum atea
for HEK removal.
•tripping
A groundwater treatment ayatea)
for HEK removal would be
relatively eaay to construct and
Implement.
A groundwater treatment ayaten
for HEK removal would be
relatively eaay to construct and
Implement.
Effectiveness
May not be effective became
high carbonate levele Interfere
with ozone oxidation; ultra-
violet light Intensity reduces
rapidly due to filming of
quartz tubea.
Influent HEK concentrations are
difficult to predict.
Hay not be effective becauae
high calcium carbonate calcium
•ulfate concentrations will
acale portlona of theae units.
Influent HEK concentrations are
difficult to predict.
Relative Cost
High
Medium to High
Ln
RDD\RB2\037.50-2
-------
ruble b-23
DETAILEU ANALYSIS OK UROUHUUATER ALTERNATIVES
Alternative I
..at
o Croundwecer quality
monitoring
o Aquifer uee
reetrlctione
o Mo remedial action
taken
Alternative 2
t_n
I
-J
NJ
Community
Acceptance
o Groundwater quality
monitoring
o Extract groundwater
•t 400 gpm for 20
yeara using four
production wall*
o Pipe to UnlDynamlce
facility
o Treatment will
Include volatile
organic air
•tripping with vapor
phaae carbon and
granular activated
carbon pollabing
o Reinject treated
water Into Unit A
aquifer
o Treatment of
at ripped volatllea
by vapor phaee
carbon
o ConxBunlty la pro-
tected dutIng con-
conat ruct ion and
implementation
o Worker* are pro-
tected during con-
at ructIon and
implementat ion
Alternative
o Groundwater quality
monitoring
o Extract groundwater
at 1,000 gpm for
2i yeara ualng nine
production welia
o Pipe to UnlDynanica
facility
o Treatment will
Include volatile
organic air
•tripping with vapor
phaae carbon and
granular activated
carbon poliehing
o Kelnject treated
water into Unit A
aquifer
o Treatment of
•tripped volatllea
by v«por phaae
carbon
o Community ia pro-
tected during con-
struction and
implementat Ion
o Workera are pro-
tected during con*
at ruction and
Implementation
Alternative
o Groundwater quality
monitoring
o Extract groundwater
at 1,000 gpm for
11 yeara uaing 24
production wella
o Pipe to UniUynamlca
facility
o Treatment will
Include volatile
organic air
atrlpping with vapor
phatte carbon and
granular activated
carbon poliahlng
o Keinject treated
water Into Unit A
aquifer
o Treatment of
stripped volatileu
by vapor phaae
carbon
o Community 10 pro-
tected during con-
at ruction and
implementation
o Workera are pro-
tected during
conatructIon and
Implementat ion
Aitentat lue *>
o Croundwater quality
monitoring
o Extract groundwater
• t 40 gpm for
25 yearn ualng one
extraction well
o Treatment wl11
Include volatile
organic air
atripping and
granular activated
carbon poliahlng
o Discharge Into
Subunli C aquifer by
reinjectlun
o Other beneficial
ueea way be
appropriate and
would be evaluated
AltecnatIve 6
o Community 10 pro-
tected during con-
at ruction and
Implemeulat Ion
o Worker* are pro-
tected during cou-
nt ruci lun and
implementation
o Comunily acceptance
for drinking water
end uue will be low
o Cruuitdwater quality
monitoring
o Extract groundwater
ai. 60 gpm for
2i yearn uaing one
extraction well
o TreaLment will
Include volatile
organic air at rip
ping and granular
activated carbon
o 1)1 ucharge Into
Subunli C aquifer by
reinjectIon
o Other beneficial
utteu may be
appropriate and
would be evaluated
o Community la pro-
tected during con-
«t ruct ion and
Implementation
o Workert* «re pro-
tected during con-
«t ructIon and
liapleokentat Ion
o Cumnunlty acceptance
for drinking water
end uae will be low
-------
Table 5-21
(Cunttnued)
Alternative I
Alienist Ive 2
Short Term
Effectiveness
ProtectIveneas
Lone-Term
Effect Iveneas
and Permanence
unity Is pro-
tected by monitoring
•nd aquifer use
restrictlone
o No adverse Impacts
oa the environment
from activities
o Objective* may Dot
be achieved
o Silatlng eod future
rleke remain
o Short-term environ-
mental Impact a
minimal
o Construction com-
plete within I yeer
o Croundweter objective
achieved lo 20 year*
with renoval of 5
pore volume a
o Some risk remalne
at coDclualoo of
remedial activities
o Conventional and
specialized tech-
nologies with proven
performance
o Requires periodic
maintenance and
Inspection during
operations
Alternative 3
o Short-tern environ-
mental Isipacts
minimal
o Construction com-
plete within 1 year
o Couodwater objective
achieved In 25 yeara
with removal of 5 pore
volumes
o Low risk remain* at
conclusion of
remedial actlvltlee
o Conventional and
specialised tech-
nologies with proven
performance
o Requires periodic
maintenance and
Inspection during
operations
Altcrnstlve
o Short-term environ-
mental Impact*
minimal
o Construction com-
plete within I year
6 months
o Croundwater objective
achieved in I/ yeara
with removal of
i pore volumes
o Low risk remains at
conclusion of
remedial activities
o Conventional and
specialized tech*
oologlea with proven
performance
o Requlree periodic
maintenance and
Inspection during
operation*
Alternative
Short-term environ-
ment al Impact0
minimal
o Construrtlun com-
plete within
6 months
o Croundwatar objective
achieved In 25 yeara
with removal of
5 pore volume*
o Low rlek remains at
conclusion of
remedial actIvltlee
o Risk Incurred of
degrading water
quality
o Conventional tech-
nologies with proven
performance
o Requires periodic
maintenance and
Inspection during
operatlone
o Drinking water end
use requirea fre-
quent monitoring of
VOCa In treated
water
Alternative 6
o Short-term environ-
mental Impact a
minium 1
a Conutruction coa-
pleie wlihln
6 mom ha
o Croundwater objective
achieved In 25 year*
with removal of
5 pore volume*.
o Low risk remains at
conclusion of
remedial activities
o Rtak Incurred of
degrading water
qualIty
o Conventional tech-
nologies with proven
performance
o Require* periodic
Maintenance and
Inspection during
operations
o Drinking water end
use requ1 res freque
monitoring of
VOCa In treated
water
KDU/HIB/079-?
-------
Table i-2'i
(Cont iiiued)
Alternative I
o No remedletloo
Alternative 2
KobllUv, yr
Volume
(Con*Idere
alternativa-
specific
o Croundwater extrac-
tion to reduce
•ability or migra-
tion of contaminated
groundwater
o Reduce* volume of
contaminated ground-
water by treatment
o Reducee nobility of
organic* in ground-
water by collection
o Reduce* volume of
volatile* in air by
t reatmeot
o Reduce* toilcity of
collected organic*
by offalte iDC 1DCra-
tion at a TSD
facility
o A calculated 1U.200
pound* of TCE and
other VOC* ie removed
In 20 year*
o High TDS ellmlnatee
t'.eam etripplng,
U //ozone„ etc.; thu*
removal of M£K to
health advleory
level* may not be
realized
Alternative 3
o Ct ••uitdvater extrac-
i I .» to reduce
mobility or algra-
ilou of contaminated
groundwater
o Reduce* volume of
contaminated ground
water by tTenement
o Reduce* mobility of
organic* la ground-
water by collect loo
o Reduce* volume of
volatile* in air by
t reatment
o Reduce* toxiclty of
collected organlce
by offalte Incinera-
tion at a TSO
facility
o A calculated U/,900
pound* of TCE and
01 her volat1Ie
organic* currently
eetlmated to be
preaent ie removed
fro* the grouodweter
in 2i yeara
o High TOS eliminate*
ateam atrlpplng,
UV/ozone, etc.; thua
remove I of HEK to
health »dvl»ory
level* may not be
realized
Alternative
o Crouiidweter exlrac-
tloo to reduce
mobility or migra-
tion of contaminated
groundwMter
o Reduce* volume ol
contaminated ground
water by treatment
o Reducee volume of
volatile* in air by
treatment
from Subunlt A.
o Reduce* toil<:lty of
collected organlcu
by affalte Inclnera
Hun at a TSU
facility
o A c«lculated IIB.20O
pound* of TCE and
other volatile
org*nlca currently
ewtlmated to be
preaent 1* removed
from the grouodwater
In II yeara
o High TDS eliminate*
eteam stripping,
UV/ozone. etc.; thu*
removal of MEK to
health advlwury
levele may not be
realized
jii tve
o Crouodwater extr«c-
tlon to reduce
mobIllty or mlgra-
t i-*n of cOntamlnaied
gruuudwater
o Reduce* volume ot
contaminated ground-
weier by treatment
Reduce* volume of
volatile* in elr by
treatment
pound* of TCt mid
other volatile
orgttiili;* currently
e*l IjAaied to be
preeent fle removed
frua the groundwater
in 2i year*
o Croundwater extrac-
lIon to reduce
mobility or migra-
tion of contaminated
groundwater
o Reduce t* volume oi
cctnl MJQlnaied g round-
water by treatment
o Reduce* volume of
volttiI leu lu air by
t reMtment
o A Cttlculatvd
/ poundtt ol ICE and
other voiai I !«•
organic* currently
e»l touted to be
present 1 * removed
from the grouiidwmer
In 2!» years
-------
Table 5-21
(Continued)
Alternative
Alternative 2
Implement-
ablllty
Ul
I
-J
cn
o Convent ton*1 t ec h -
nologlee far extrac-
tion, treatment of
organic*
o High TDS My make
relnjection of
treated water diffi-
cult to Implement.
Ralnjecclon of Sub-
unit A water haa
been aucceaafully
Implemented In the
eouth portion of
the •lie
o Adequate work force
and equipment
available
o Good performance In
collection and treat-
ment of volatile
organlca
o Low reliability and
high maintenance of
relnjectlon ayatem
o Requlrea periodic
monitoring
Alternative 3
o Conventional tech
nologlee for extrac
lion, treatoMnt of
organlca
Alternative <*
o Conventional tech
nologlea for extrac-
I Ion, t reatmeiit
of organlca
Alternative
o High TDS may make
relnjection of
treated water diffi-
cult to Implement .
Ralnjectlon of Sub-
unit A water hae
been aucceaafully
Implemented In the
aouth portion of
tha alte
o Adequate work force
o High TDS nay make
re
tr
cu
Re
un
be
n) ctlon of
at d water dlffl
t o Implement
nj ction of Sub-
t water haa
n ucceaafully
Implemented In the
aouth port Ion of
the alte
o Adequate work force
and equipment
available
o Good performance In
collection and treat-
ment of volatile
organlca
o Low reliability and
high maintenance of
reinjectlon ayatem
o Requlrea periodic
monitoring
and equipment
available
o Good performance In
collection and treat-
ment of volatile
organlca
o Low reliability and
high maintenance of
relnjectlon ayatem
o Requlrea periodic
monitoring
o Conventional tech-
nologlea for extrac-
tIon. treatment of
organlca, and reln-
jectlon of treated
water or drinking
water end uae
Alternative 6
o Adequate work force
and equipment
available
o Good performance In
collection and treat-
ment of volatile
organlca
o Good reliability,
but high maintenance
of relnjectlon
ayateo
o Relnjectlon end uae
requires periodic
monitoring
o Drinking water end
uae requlrea
frequent monitoring
of VOCa In treated
water
o Drinking water end
uae requlren high)y
reliable pruceaa
cont rol Inat rument a -
11 on
o Conventional tech-
nologlea for extrac-
t Ion. i reattnent of
organlca, and re In-
ject Ion of treated
witter or drinking
water end uae
o Adequate work force
and equipment
available
o Good performance In
collection and treat-
ment of volat1le
organlce
o Good reliability,
but high maintenance
of relnjectlon
eynten
o Relnjectlon end uae
requlrea periodic
oonItorIng
o Drinking water end
uae requIrea f re -
quent monitoring of
VOCa In treated
water
o Drinking water end
uae requlrea highly
reliable proceue
conlrol Inat ruraen-
tat Ion
-------
Table i-2J
(Com Itiued)
Alternative I
sime
Acc«Ptanc«
o Agency approval
unlikely
o Aquifer uae nonl-
tared through AOWB
permitting prugran
Ol
I
-J
CupItsi Cu«l*
Annual CoMIs
Pr«aeot Worth
Co*t*
$ 0
$ 10,000
$461.000
CogplUnce
With ARAla
o ARARa may not b«
achieved
Alternative 2
o Require* pqcUWP* or
Type 2 water right
o High IDS eilJBinatee
ataaa atrlpping,
UV/OSOUe, atC.j thua
removal of MCK to
h«aUb advlaory
lava la nay not be
re«Iliad
o Substantial penalt
raquireaenta for
groundwater re in-
ject ion Mat be net
o Approval from
agendas likely
52.bej,ooo
$ 261,000
$b.B61,000
ARAR« nay noi be
achieved
o Require* PQCUWI* or
Type 2 water right
o High IDS eliminate*
tftaam atrlpplog.
UV/ozone, ate.; tbua
removal oft HEK to
health advlaory
level* may not ba
realized
o Subatantlal permit
requirementa for
groundwater rein-
jection BMiat ba met
o Approval from
agenclea Hkaly
$ 4.041,000
$ S/6,000
$12,IS/,000
o KFA target leveU and
ARAKa baited on HCL*
for groundwater
achieved at con-
clusion of raawdial
action
o Heel* ARAHa for end
u«e of recharge
Aiiermttlve 4
o He quire*. PtjCUUP or
Typa 2 water right
o High TDS ellnlitatea
ateam wtripping.
UV/ozone, etc.; thue
reouval ol HEK to
health advleery
level* caay not b«
reallxed
o Sub«tantlal pemlt
requt rementa for
groundwater rein-
jectiou BUMI ba net
o Approval frucn
agenciee likely
$ 9,138.000
$ 1,621,000
o EPA target I eve la «ud
AftAMtf baued on HCLa
for groundwater
achieved at con-
clusion of renedial
action
o Heetd ARAH* tor
relnfectIon to
Subunlc A aquller
Alternai Ive *>
o Require* pqcWUl* or
Type 2 water right
o Potential adverse
Impact on other
groundwater u«era
o Subaiantlal permit
requirement a lor
groundwater reln-
jectlon muat be net
o Approval from
agenclea likely
$ 97.000
Sl.B/0,000
o Drinking water end
uue alternate may
decrease caplidl
coal, but 0en«1tIve
to proceuu inuirumen-
tat ion requirement*
o ARARa baeed on HCL*.
for grouiidwater
achieved at con-
clusion of remedial
action
o Heeta ARARv lur
re Inject Ion to
Subunii C aquller
o Heeie ARAKa lur
diInking water end
Utttt
Alternative 6
o Require* KjCWWP or
Type 2 water right
o Potential adverse
impact on other
groundwater uaera
o Substantial permit
requirement* for
grouiidwater rein-
jectlon muat be met
o Approval from
agei.clee likely
$ :> 14.000
$ 10!»,400
$2,000,OUO
o Drinking water end
ube alternute may
decrease c«pli*|
com , but uenalt Ive
lo pru<:ea« Instrumen-
tation requlremente
o AKARd baued on HCL*
for grouiidwater
achieved at con-
clusion of remedial
MCI ion
o Heetn ARARtt lor
reinfection iu
Subunlt C aquiter
o Heetu AHAKt. lor
drinking water end
use
•pqUWUP-Poor Quality Groundwater Withdrawal Permit.
-------
All«rn«tlv« I
Alternative 1
Overall frotec-
t ton of Hua«fl
H««lth «nd th»
Bnvlroraaent
o Rlak* ra«uiln
o Rl*k« to hmuD health
mrm reduced; contaoi-
InatlOD will still
• lUt In Subunlt A
•t concluclon of
reaedlal action
Table S-2)
(Continued)
Alternative 3
0
i
0
0 1
i
ov with abort Unple
aenfatlon time* for
treatment and pro
ect Ion of communl ty
ind worker*
p to the point
apt u re TCE In
xceea of 100 ppb
aocon occur*; pump
ng to capture TCE
o lover concentrat-
ion* may not reault
n further rl*k
eduction
xmg-ten* permanent
f feet Iveneaa
Alternative *
low with *hort Imple
mentation tlmea for
t reatment and pro
tectlon of comuinlty
and worker*
o Bl*k* are reduced
up to the point
where extraction to
capture TCE In
excess of 100 ppb
laocon occurs; pump
Ing to capture TCE
to lower concent ra-
t tone may not reault
in further risk
redact Ion
o Long-term permanent
af fectlvenea*
Alternative i
low with abort Imple
mentation tlmea for
treatment and pro
tectlon of community
and workera
o Rlaka are reduced
with objective* met
In 2i year*
o Increeee rlaka from
migration of
Alternative 6
low with short Iraple
mentation time* for
1 real mem and pro
tectlon of cocnminlty
and worker** ^ i
with objectives met
In 2i year*
o Increaae rlska from
mlgrat ton of
i In order to remove
MEK to draft health
adv1aory leve1*.
additional extract*
tlon and granular
activated carbon
treatment would be
required; the extent
of additional
extraction ha* not
been precisely
calculated.
Draft health advl-
aory level* are not
AJtAJt* and may only
be considered a*
water quality goal*.
o In order to remove
HEX to draft health
advlcory levels,
additional extrac-
tion and granular
activated carbon
treatment would be
required; the extent
of additional
extraction ha* not
been precisely cal-
culated.
Draft heeltb advi-
aory level* are not
ARAB* and may only
be considered a*
water quality goal*.
contamlnanta
• In order to remove
MEK to draft health
adv1aory leve1 a,
additional extrac-
tion and granular
activated carbon
[reatment would be
required; the extent
of additional extrac-
tion ha* not been
precisely calculated.
Draft health advi-
sory levels are not
ARAB* and may only
be considered as
water quality goals.
contamlnante
-------
Table 5-24
DETAILED COST ANALYSIS FOR GROUNDWATER ALTERNATIVES
ALTERNATIVE 2
i,000-GPM EXTRACTION/AIR STRIPPING/
VAPOR PHASE PHASE CARBON/
GRANULAR ACTIVATED CARBON POLISHING/
REINJECTION
DIRECT COSTS
Groundwater Extraction System
Nine wells, six of 115-gpm capacity and
three of 100-gpm capacity, 7.5 hp, 231 feet
of head at $22,000 each; six stainless steel
pumps at 115 gpm, three pumps at 100 gpm at
56,000 each; FRP piping, 3-inch to 6-inch-
diameter, total length of 10,700 feet at
$329,200 $ 567,000
Air Stripping System
Two FRP air stripping towers, 8.0 feet
diameter by 20 feet total height with 15
feet polyethylene packing; 25.00 cfm blower
(30 hp), operating at G/L of 160, with
liquid pumps (25 hp), flowmeters, valves
piping, and fittings 390,000
Source: Vendor Information
Vapor Phase Carbon System
Skid-mounted vapor phase carbon system sized
for 50,000 cfm gas flow, steam boiler, off-
gas chiller, knockout drum, and preheater 380,000
Source: Vendor Discussions
Granular Activated Carbon Polishing System
Skid-mounted - two granular activated carbon
beds, each 12 feet in diameter, 12 feet in
height, containing 38,000 pounds granular
activated carbon. Beds piped in series,
upflow and backwashable. Includes backwash
pumps, pipes, and fittings. 244,000
Source: Vendor Discussions
Foundation Pad
Dimensions: 50 feet by 100 feet x 6 inches
with 6-inch curb. Concrete at $125/cubic
yard. Float finish. 15,500
inks
Two 30,000-gallon epoxy-coated steel feed
and treated water tanks
One 10,000-gallon epoxy-coated tank 88,000
5-78
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 2 (continuedl
DIRECT COSTS (continued)
Utilities Hookups
480V/3-phase 600-amp electrical service is
provided to the process pad: $30,000
Gas: $9,000
Water: $6,000 45,000
Discharge System
Eighteen 60-gpm-capacity reinjection wells
at $20,000/well with 14,000 feet of 8-inch-
diameter pipe; includes trenching and
backfilling 1,065,000
Interunit Piping
8 percent of capital equipment cost 140,000
Instrumentation
12 percent of capital equipment cost (not to
include discharge system) 140,000
Installation and Testing
Mobilization/demobilization: $25,000
Tank rigging and replacement: $33,000
Process piping: $75,000
Electrical: $25,000
Pressure and water testing: $3,500 161.500
Subtotal Direct Costs $3,236,000
INDIRECT COSTS
Engineering
12 percent of total direct costs $ 345,000
Startup
One Engineer at 50 hours/week at $70/hour 14,000
Permits
Per onsite estimate 15,000
Contingency
15 percent of total direct costs 431.000
Subtotal Indirect Costs $ 805,000
Total Capital Costs, Alternative 2 $4,041,000
5-79
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 2 (continued)
ANNUAL COSTS
Monitoring $ 30,000
Groundwater Extraction System
Electrical at $0.10/kWh: $43,000
Maintenance (pump and well) at $700/well:
$6,300
Maintenance (piping repair) at 1 percent of
withdrawal system capital cost: $6,700 56,000
Air Stripping System
Electrical: $105,000
Biocide: $87,500
Maintenance at 3 percent of air stripping
system capital cost: $11,700 204,000
Vapor Phase Carbon System
Electrical: $62,500
Maintenance at 3 percent of vapor phase
system capital cost $11,400 73,900
Granular Activated Carbon Polishing System
Includes electrical, regeneration of 51,000
pounds carbon/year at $1.20/pound 70,000
Plant Operator
1/2 time to conduct maintenance, repair, and
sampling activities 15,000
Sampling
Two samples per week 10,000
Waste Disposal
Recycling/incineration of concentrated
liquid organic at approved facility 5,400
Tank Maintenance
Painting/cleaning/repair 1,500
Process Automation
2 percent of instrumentation capital costs
plus periodic cleaning of probes 3,000
Discharge System
Well pump maintenance and pipe repair at 10
percent of discharge system capital costs 107.000
Total Annual Costa, Alternative 2 $ 576,000
5-80
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 3
3,000-GPM EXTRACTION/AIR STRIPPING/
VAPOR PHASE CARBON/
GRANULAR ACTIVATED CARBON POLISHING/
REINJECTION
DIRECT COSTS
Groundwater Extraction System
24 wells at $20,000 per well;
24 stainless steel pumps, 125 gpm, 15 hp,
300 feet of head at $5,000 each;
FRP piping, 3-inch to 14-inch diameter,
total length of 20,000 feet: $775,000 $1,375,000
Air Stripping System
Two 14-foot-diameter by 20-foot-high FRP air
stripping tower with 15 feet polyethylene
packing. 3,000-gpm liquid flow rate,
approximately 60,000-cfm gas flowrate/tower,
TCE influent at 34,000 ppb, blower,
flowmeter, valves, piping, and fittings 755,000
Vapor Phase Carbon System
Skid-mounted, 120,000-cfm gas flow rate,
steam boiler, off-sas chiller, knockout
drum, and preheater 675,000
Granular Activated Carbon Polishing System
Two parallel skid-mounted trains of two
granular activated carbon upflow beds,
connected in series, backwashable;
containing 38,000 pounds granular activated
carbon per bed; includes backwash pumps,
pipes, and fittings 488,000
Foundation Pad
100 feet by 100 feet by 6-inch reinforced
concrete, //4 rebar each face, each way,
concrete at $125/cubic yard, float finish 28,000
Tanks
Two 45,000-gallon epoxy-coated steel feed
and treated water tanks;
one 30,000-gallon epoxy-coated backwash tank 128,000
Utilities Hookups
Includes gas, water, and electrical 60,000
Interunit Piping
8 percent of capital equipment costs 164,000
Instrumentation
12 percent of capital equipment costs 260,000
5-81
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 3 (continued)
DIRECT COSTS (continued)
Discharge System
48 - 65-gpm-capacity injection wells at
$20,000 per well with 14,000 feet of 14-
inch-diatneter pipe. Includes trenching and
backfilling. 3,059,000
Installation and Testing
Includes installation of tanks and interunit
piping, testing of well pumps and pipelines,
mobilization, and demobilization 180.000
Subtotal Direct Costs $7,172,000
INDIRECT COSTS
Engineering
12 percent of total direct costs S 861,000
Startup
One Engineer at 50 hours/week at $70/hour
for 4 weeks 14,000
Permits
Per onsite estimate (FS) 15,000
Contingency
15 percent of total direct costs 1.076.000
Subtotal Indirect Costs $1,966,000
Total Capital Costs, Alternative 3 $9,138,000
= =3 CO == = = =3 = =3
ANNUAL COSTS
Monitoring $ 30,000
Groundwater Extraction System
Electrical at $0.10/kWh: $117,000
Maintenance (pump and well) at S700/well:
$17,000
Maintenance (piping repair) at 1 percent of
withdrawal system capital cost: $14,000 148,000
5-82
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 3 (continued)
ANNUAL COSTS (continued)
Air Stripping System
Electrical: $265,000
Biocide: $263,000
Maintenance at 3 percent of air stripping
system capital cost: $23,000 $ 551,000
Vapor Phase Carbon System
Electrical: $100,000
Maintenance at 3 percent of vapor phase
carbon system capital costs: $20,000 120,000
Granular Activated Carbon Polishing System
Electrical: $75,000
Carbon regeneration at 228,000 pounds/year
at $1.20/pound: $274,000
Maintenance at 3 percent of granular
activated carbon polishing system: $15,000 • 364,000
Discharge System
Pipeline maintenance at 10 percent of
discharge system capital costs • 306,000
Plant Operator - Full-time 30,000
Sampling
Two samples per week 10,000
Waste Disposal
Recycling/incineration of concentrated
liquid organic at approved facility 50,000
Tank Maintenance
Painting/cleaning/repairing 5,000
Process Automation
2 percent of instrumentation system capital
costs plus periodic cleaning of probes 7.000
Total Annual Costs, Alternative 3 $1,621,000
5-83
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 4
40-GPM EXTRACTION/AIR STRIPPING/
GRANULAR ACTIVATED CARBON POLISHING/
REINJECTION
DIRECT COSTS
Groundwater Extraction System
One well of 40 gpm capacity at $20,000;
one stainless steel pump, 40 gpm, 7-1/2 hp,
400 feet of head at $5,000; FRP piping, 2-
inch for 400 feet: $3,800 $ 28,800
Air Stripping System
One 1-1/2-foot-diameter by 17-foot-high FRP
air stripping tover with 12 feet
polyethylene packing, 40-gpm liquid flow
rate, 535-cfm gas flow rate, 1-hp blower,
TCE influent at 21 ppb, flowmeter, valves,
piping, and fittings 10,000
Granular Activated Carbon Polishing System
Two 2,000-pound granular activated carbon
beds connected in series, approximately 4
feet diameter by 11 feet high each, 40-gpm
flew rate, TCE influent at <5.0 ppb, 99
percent removal 17,800
Foundation Pad
50-foot by 100-foot by 6-inch reinforced
concrete with 6-inch curb, #4 rebar each
face, each way, concrete at $125/cubic yard,
float finish 15,500
Tanks
Two 5,000-gallon epoxy-coated steel feed and
treated water tanks
Two 1,125-gallon epoxy-coated backwash tanks 19,000
Utilities Hookups
480V/3-phase 400-amp electrical service
transformer to process pad: $25,000
Gas: $9,000
Water: $6,000 40,000
Discharge System
Two 20-gpm-capacity injection wells at
$20,000 each with 6,000 feet of 2-inch-
diameter pipe; includes trenching and
backfilling 150,000
Interunit Piping
FRP piping 2-inch for 5,600 feet; includes
trenching and backfilling, 8 percent of
capital equipment costs 19,300
5-84
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 4 (continued)
DIRECT COSTS (continued)
Instrumentation
12 percent of capital equipment costs 29,000
Installation and Testing
15 percent of capital equipment costs 36.300
Subtotal Direct Costs S 365,700
INDIRECT COSTS
Engineering
12 percent of total direct costs 44,000
Startup
10 percent of capital equipment costs 24,000
Permits
Per onsite estimate (FS) 15,000
Contingency
15 percent of total direct costs 55.000
Subtotal Indirect Costs $ 138,000
Total Capital Costs, Alternative 4 $ 503,700
= SS3=I = = SS = := =
ANNUAL COSTS
Monitoring S 30,000
Groundwater Extraction System
Electrical at $0.10/kWh: $5,000
Maintenance (pump and well) at $700/well:
$700
Maintenance (piping repair) at 1 percent of
withdrawal system capital cost: $2,900 8,600
Air Stripping System
Electrical: $8,000
Biocide: $3,500
Maintenance at 3 percent of air stripping
system capital cost: $500 12,000
GAC Polishing System
Includes electrical for 1-hp feed and
backwash pump and periodic changeout and
decommissioning (one bed per year) 4,000
5-85
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 4 (continuedI
ANNUAL COSTS (continued)
Plant Operator
1/2 time of annual salary of $30,000 $ 15,000
Sampling
Two samples per week 10,000
Tank Maintenance
Painting/cleaning/repair 1,500
Process Automation
2 percent of instrumentation capital cost
plus periodic cleaning of probes 1,000
Discharge System
10 percent of discharge piping capital cost 15.000
Total Annual Costs, Alternative 4 $ 97,000
5-86
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 5
60-GPM EXTRACTION/AIR STRIPPING/
GRANULAR ACTIVATED CARBON POLISHING/
REINJECTION
DIRECT COSTS
Groundwater Extraction System
One well of 60 gpra capacity at $20,000;
one stainless steel pump, 60 gpm, 7-1/2 hp,
400 feet of head at $5,000; FRP piping, 2-
inch for 400 feet: $3,800 $ 28,800
Air Stripping System
One 2-foot-diameter by 17-foot-high FRP air
stripping tower with 12 feet polyethylene
packing, 60-gpm liquid flow rate, 960-cfm
gas flow rate, 1-hp blower, TCE influent at
5 ppb, flowmeter, valves, piping, and
fittings 10,000
Granular Activated Carbon Polishing System
Two 2,000-pound granular activated carbon
beds connected in series, approximately 4
feet in diameter by 11 feet high each, 60-
gpm flow rate, TCE influent at <5.0 ppb, 99
percent removal 17,800
Foundation Pad
50-foot by 100-foot by 6-inch reinforced
concrete with 6-inch curb, //4 rebar each
face, each way, concrete at $125/cubic yard,
float finish 15,500
Tanks
Two 7,500-gallon epoxy-coated steel feed and
treated water tanks
two 2,000-gallon epoxy-coated backwash tanks
24,800
Utilities Hookups
480V/3-phase 400-amp electrical service
transformer to process pad: $25,000
Gas: $9,000
Water: $6,000 40,000
Discharge System
Two 30-gpm-capacity injection wells at
$20,000 each with 6,000 feet of 2-inch-
diameter pipe; includes trenching and
backfilling 150,000
Interunit Piping
8 percent of capital equipment costs 19,800
5-87
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 5 (continued!
DIRECT COSTS (continued)
Instrumentation
12 percent of capital equipment costs 29,700
Installation and Testing
15 percent of capital equipment costs 37.000
Subtotal Direct Costs $ 373,400
INDIRECT COSTS
Engineering
12 percent of total direct costs S 44,800
Startup
10 percent of capital equipment costs 24,800
Permits
Per onsite estimate (FS) 15,000
Contingency
15 percent of total direct costs 56.000
Subtotal Indirect Costs S 140,600
Total Capital Costs, Alternative 5 $ 514,000
ANNUAL COSTS
Monitoring $ 30,000
Groundwater Extraction System
Electrical at $0.10/kWhs $7,500
Maintenance (pump and well) at $700/well:
S700
Maintenance (piping repair) at 1 percent of
withdrawal system capital cost: $2,900 11,100
Air Stripping System
Electrical: $12,000
Biocide: $5,300
Maintenance at 3 percent of air stripping
system capital cost: $500 17,800
Granular Activated Carbon Polishing System
Includes electrical for 1-hp feed and
backwash pumps and periodic changeout and
decommissioning (one bed per year) 4,000
5-88
RDD/R82/039.50
-------
Table 5-24
(Continued)
ALTERNATIVE 5 (continued)
ANNUAL COSTS (continued)
Plant Operator
1/2 time of annual salary of $30,000 $ 15,000
Sampling
Two samples per week 10,000
Tank Maintenance
Painting/cleaning/repair 1,500
Process Automation
2 percent of instrumentation capital cost
plus periodic cleaning of probes 1,000
Discharge System
10 percent of discharge piping capital cost 15.000
Total Annual Costs, Alternative 5 $ 105,400
5-89
RDD/R82/039.50
-------
will be considered in construction plans. If pump failure
were to occur, there would be no short-term release of con-
taminants pending repair that could pose a threat to public
health or the environment.
Air stripping with vapor phase carbon (Subunit A groundwater
aquifer alternatives only) and granular activated carbon
polishing achieve the desired goal of reducing volume and
toxicity of the groundwater contaminants sufficiently to
meet the applicable and appropriate requirements and will
likely exceed those requirements. Treatment of contaminated
groundwater by air stripping has been shown to be very
effective with removals of organic contaminants often
exceeding 99.9 percent. Granular activated carbon polishing
for removal of MEK and acetone may be equally as effective.
These procedures are relatively predictable, and they have
been used successfully at a number of CERCLA sites. Equip-
ment is relatively easy to operate once initial adjustments
have been completed. Operator training will be required.
Occasional attention for adjustment, monitoring, and testing
will be required. With industrial-grade components and reg-
ular preventive maintenance, process integrity should be
10 years or more. Scaling of air stripping tower internals
has been a problem at some sites. A small amount of anti-
sealant, such as hypochlorite, would be required to remedy
this. Also, spent carbon from the granular activated carbon
beds will require periodic regeneration.
If, in the implementation of the remedial action, EPA
determines that air stripping cannot treat MEK to the level
required by the ARARs, then hot air stripping and scale
control methods will be employed unless EPA determines that
the technology is impracticable. If the technology to treat
MEK is impracticable, EPA will waive compliance with the MEK
ARAR pursuant to CERCLA Section 121(d)(4), and set an
alternative limit that is protective of human health and the
environment.
Numerous vendors are available to produce the process com-
ponents. Conventional materials for construction are
required.
All equipment items can be shop-fabricated and skid-mounted,
making field erection easier. Construction for implementa-
tion of Alternatives 2 and 3 could take up to one year, and
6 months for Alternatives 4 and 5. Catastrophic failure of
components is unlikely, and any threat to public health and
the environment is relatively low.
5-90
HDD\R225\027.50
-------
For the Subunit A groundwater treatment alternatives, air
emission controls will be placed on the air stripping
towers. SARA states that a remedy should reduce the toxic-
ity, mobility, and volume of contaminants. The Maricopa
County Air Pollution Control Board requires that all new
plants with air emissions "will adequately dilute, reduce,
or eliminate the discharge of air pollution to adjoining
property." This requirement is also known as reasonably
achievable control technology (RACT), and in this case, RACT
is air emission controls such as activated carbon adsorption
5-91
RDD\R225\027.50
-------
6. REFERENCES
Doull, J., C. D. Klaassen, and M. D. Amdur. 1980. Toxicol-
ogy. MacMillan.
National Research Council (NRC). 1977. Drinking Water and
Health. Vol 1. Washington, D.C.
National Research Council (NRC). 1980. Drinking Water and
Health. Vol 3. Washington, D.C.
Sittig, M. 1981. Handbook of Toxics and Hazardous Chemi-
cals. Noyes Publications, Park Ridge, New Jersey.
UniDynamics Phoenix, Inc. 1989. Remedial Investigation/
Feasibility Study. Phoenix-Goodvear Airport.
U.S. EPA. 1985a. Safe Drinking Water Act. 40 CFR 141,
November 15, 1985.
U.S. EPA. 1985b. Chemical. Physical and Biological Proper-
ties of Compounds Present at Hazardous Waste Sites. Final
Report. Office of Waste Programs Enforcement, Office of
Solid Waste and Emergency Response, Washington, D.C.
U.S. EPA. 1987a. Final Feasibility Study for Section 16
Operable Unit. Goodyear, Arizona. October 19, 1987.
U.S. EPA. 1987b. Record of Decision Summary for Section 16
Operable Unit. Phoenix-Goodyear Airport Superfund site.
September 25, 1987.
U.S. EPA. 1988. Federal Register. Drinking Water Regula-
tions; Maximum Contaminant Level Goals and National Primary
Drinking Water Regulations for Lead and Copper; Proposed
Rule 40 CFR Parts 141 and 142. August 18, 1988.
U.S. EPA. 1989a. Remedial Investigation/Feasibility Study.
Phoenix-Goodvear Airport.
U.S. EPA. 1989b. Integrated Risk Information System (IRIS)
Database.
U.S. EPA. 1989. Federal Register. National Primary and
Secondary Drinking Water Regulations; Proposed Rule 40 CFR,
Parts 141, 142, and 143.
6-1
RDD\R225\027
-------
Appendix A
INDEX OF ADMINISTRATIVE RECORD
-------
Appendix A
INDEX OF ADMINISTRATIVE RECORD
Date of
Publication
Sept. 1983 Ecology and Environment, Inc. Site Inspec-
tion Report. Goodyear Aerospace Corporation.
September 1983.
Presents sampling results of community
wells in the vicinity of the Phoenix-
Goodyear Airport. Identifies potential
waste generators in the area.
June 1984 Ecology and Environment, Inc. Final Workplan
RI/FS Litchfield Airport Area. Goodyear.
Arizona. June 1984.
Describes the activities to be carried
out and the methodology for the remedial
investigation and feasibility study of
the Litchfield Airport Area (later
renamed the Phoenix-Goodyear Airport).
June 1984 Unidyanamics Phoenix, Inc. Drv Well Soil
Testing Project. Unidynamics Phoenix. Inc.
Goodyear. Arizona. Prepared by Western
Technologies, Inc. June 1984.
Describes volatile organic compound
sampling and results of soil samples
collected near dry wells at the
Unidynamics facility.
Aug. 1984 Engineering-Science, Inc. Contamination
Assessment Plan. August 1984.
Provides revised plan for assessment of
groundwater contamination in the vicin-
ity of the Goodyear Aerospace Corpora-
tion facility (currently owned by Loral
Corporation). This was done as a
requirement of Administrative Order 84-
02 issued by EPA, Region IX.
A-l
RDD/R94/029.50
-------
Date of
Publication
Oct. 1984 U.S. EPA. Final Community Relations Plan.
Phoenix-Litchfield Airport Area. Prepared by
CH2M HILL. October 1984.
Prepared as part of Phase I of the RI/FS
to provide a means of gathering back-
ground, site history, and a discussion
of the concerns of interested parties.
Nov. 1984 U.S. EPA. Quality Assurance Project Plan.
Indian Bend Wash and Phoenix-Litchfield
Airport Area Sites. Prepared by Ecology and
Environment, Inc. November 1984.
Describes procedures for ensuring qual-
ity control and reliability of sampling
procedures, field measurements, equip-
ment maintenance, analytical procedures,
data management, and document control.
1985 City of Goodyear. Comprehensive Plan. City
of Goodyear. Arizona. 1985.
Presents expected future population
growth, distribution, and land use.
Jan. 1985 Unidynamics Phoenix, Inc. Results of the
First Phase of the Hydrogeologic Studies at
the Unidynamics Phoenix. Inc.. Goodyear
Facility. Prepared by Dr. Kenneth D.
Schmidt. January 1985.
Provides results and hydrogeologic
interpretations from the drilling and
sampling of four monitoring wells at the
Unidynamics site.
May 1985 Goodyear Aerospace Corporation. Evaluation
of Soils and Shallow Groundwater Contamina-
tion. Prepared by Engineering-Science, Inc.
May 1985.
A-2
RDD/R94/029.50
-------
Date of
Publication
Presexxts test locations, methods, and
results of the soil sampling and
piezometer installation program
conducted at the Goodyear Aerospace
facility.
July 1985 Unidynamics Phoenix, Inc. Results of
Continued Remedial Investigation of the
Unidynamics -Phoenix. Inc. site. Prepared by
Dames and Moore. July 1985.
Presents results for the drilling and
sampling of onsite monitoring wells,
aquifer testing, and water level
measurements .
Aug. 1985 Goodyear Aerospace Corporation. Remedial
Investigation. Phase I Results. Contamination
Assessment Report. Goodyear Aerospace
Corporation. Litchfield Park. Arizona. Pre-
pared by Engineering-Science, Inc. August
1985.
Presents results of Phase I drilling and
depth-specific monitoring well
installation. Includes water quality
and aquifer testing results.
Jan. 1986 U.S. EPA. Task 5.3 Phase I Data
Report. Phoenix-Litchfield Airport Area
Remedial Investigation. 2 Volumes. Prepared
by Ecology and Environment, Inc. January 17,
1986.
Presents data regarding aquifers, soil
materials, and contamination beneath the
PGA area.
Jan. 1986 U.S. EPA. Task 4.0 Source Verification.
Field Investigation. Phoenix-Litchfield
Airport Area Remedial Investigation. 2
Volumes. Prepared by Ecology and
Environment, Inc. January 31, 1986.
A-3
RDD/R94/029.50
-------
Date of
Publication
Provides a history of hazardous waste
disposal practices, assessment of known
and suspected contaminant source areas,
and a determination of other potential
sources.
Feb. 1986 Unidynamics Phoenix, Inc. Soil Gas Investi-
gation Report. Unidynamics Phoenix. Inc.,
Goodyear. Arizona. Prepared by Tracer
Research Corporation. February 1986.
Discusses soil gas sampling and mobile
analysis conducted at the Unidynamics
facility.
Apr. 1986 U.S. EPA. PLA Sampling Plan. Prepared by
Ecology and Environment, Inc. March 19,
1986.
Provides objectives, methods, and
procedures for semiannual well water
sampling and analysis. Sampling was
done in April 1986.
Oct. 1986 U.S. EPA. Superfund Public Health Evaluation
Manual. Office of Emergency and Remedial
Response, Office of Solid Waste and Emergency
Response, Washington, D.C. October 1986.
Establishes framework for public health
evaluations at Superfund sites.
Oct. 1986 U.S. EPA. Technical Memorandum; Results of
Soil Gas Sampling and Analysis. Phoenix-
Litchfield Airport Remedial Investigation
Phase II, Stage 1. Prepared by CH2M HILL.
October j, 1986.
Discusses soil gas sampling and mobile
analysis conducted at the PGA superfund
site from July 17 to 25, 1985.
A-4
RDD/R94/029.50
-------
Date of
Publication
Dec. 1986
Feb. 1987
June 1987
July 1987
July 1987
Goodyear Aerospace Corporation. Evaluation
of Logging and Depth-Specific Sampling of
Goodyear Aerospace Corporation Production
Wells. Prepared by Engineering-Science, Inc.
December 1986.
Presents results and interpretations of
geophysical logging and sampling of
production wells at the former GAG
facility.
U.S. EPA. Soil Gas Technical Memorandum
RI/FS. Phoenix-Goodyear Airport. Prepared
by CH2M HILL. February 27, 1987.
Discusses soil gas and mobile analysis
conducted at the PGA Superfund site from
January 3 to 22, 1987.
U.S. EPA. Soil Sampling Plan. Phoenix-
Goodyear Airport RI/FS. Prepared by CH2M
HILL. June 29, 1987.
Presents locations, rationale, and
methodology for soil samples collected
from the southern portion of the study
area.
Unidynamics Phoenix, Inc.
for Unidynamics Facility.
and Moore. July 1987.
Soil Sampling Plan
Prepared by Dames
Presents the locations, rationale and
methodology for sampling and analysis of
the Phase I soil sampling.
U.S. EPA. Interim Guidelines on Compliance
with Applicable or Relevant and Appropriate
Requirements. July 9, 1987.
Provides new guidance on selection of
ARARs and MCLs as cleanup standards for
Superfund sites. Incorporates SARA.
A-5
RDD/R94/029.50
-------
Date of
Publication
Sept. 1987
Oct. 1987
Oct. 1987
Oct. 1987
Jan. 1988
U.S. EPA. Record of Decision Summary for
Section 16 Operable Unit. Phoenix-Goodvear
Airport Superfund Site. Prepared by CH2M
HILL. September 25, 1987.
Presents EPA's preferred remedy for the
Section 16 Operable Unit.
Loral Corporation. Environmental Audit
Sampling Results. Loral Systems Division.
Litchfield Park. Arizona. Prepared by
Moretrench Environmental Services. October
1987.
Presents analytical methods, QA/QC pro-
cedures and results for 15 soil samples
collected at the former Goodyear
Aerospace facility.
U.S. EPA. Technical Memorandum Results of
the PGA Soils Investigation. Prepared by
CH2M HILL. October 5, 1987.
Presents the results of soil samples
collected from the south portion of the
study area during June and July, 1987.
U.S. EPA. Final Feasibility Study for
Section 16 Operable Unit. Goodvear. Arizona.
Prepared by CH2M HILL. October 19, 1987.
Discusses and screens remedial actions
for providing an expedited cleanup of
the Section 16 Operable Unit.
U.S. EPA. Final Air Sampling Plan. Phoenix-
Goodyear Airport RI/FS.
HILL. January 1988.
Prepared by CH2M
Presents locations, rationale, method-
ology, and analytical protocol for
ambient air samples collected from the
southern portion of the study area.
RDD/R94/029.50
A-6
-------
Date of
Publication
Jan. 1988
March 1988
April 1988
April 1988
U.S. EPA. Field Sampling Plan for
Geophysical Logging and Depth Specific
Sampling. Phoenix-Goodvear Airport Site.
Prepared by CH2M HILL. January 20, 1988.
Details procedures for logging and
sampling of three production wells
within the PGA site boundaries.
Goodyear Tire and Rubber Company. Phase II
Remedial Investigation Report Phoenix-
Goodyear Airport Site. Prepared by
Engineering-Science, Inc. March 1988.
Discusses the installation and sampling
of 19 monitoring wells, logging and
sampling of 6 production wells, and
sampling of sewers. Presents water
quality results.
Arizona Department of Environmental Quality.
Air Toxics Monitoring Study of Phoenix Urban
Area. April 1988.
Presents findings of an air monitoring
program conducted in and around the
Phoenix metropolitan area.
U,S. EPA. Technical Memorandum Installation
of Phase II. Stage 2. Groundwater Monitoring
Wells. Phoenix-Goodvear Airport RI/FS.
Prepared by CH2M HILL. April 25, 1988.
Discusses the installation of monitoring
wells installed at the PGA site from
March 15, 1987, to January 1988. Pre-
sents results of geophysical logging,
aquifer testing, and water quality
sampling.
A-7
RDD/R9A/029.50
-------
Date of
Publication
August 1988 Unidynamics Phoenix, Inc. Results of the
Phase II Groundwater Investigation.
Unidynamics RI/FS. Prepared by Dames &
Moore. August 2, 1988.
Discusses installation of nine monitor-
ing wells near the Unidynamics facility.
Includes water quality data, water lev-^1
data, and results cf geophysical logging
and aquifer testing.
December 1988 U.S. EPA. Guidance on Remedial Actions for
Contaminated Groundwater at Superfund Sites.
Office of Emergency and Remedial Response.
December 1988.
This guidance focuses on policy and
decisionmaking issues associated with
the development, evaluation, and
selection of groundwater remedial
actions at Superfund sites.
January 1989 Arizona Department of Health Services.
Letter from Norman J. Peterson to
Jess A. Brown. January 3, 1989.
This letter explains the rationale and
lists the ADHS health-based soil
cleanup guidance levels for specific
VOCs and pesticides.
June 1989 U.S. EPA. 9 volumes. Phoenix-Goodvear
Airport Remedial Investigation/Feasibility
Study. Public Comment Draft. Volumes I
through VI prepared by CH2M HILL. Volumes
VII and VIII prepared by Unidynamics
Phoenix, Inc. Volume IX prepared by the
Arizona Department of Water Resources.
June 7, 1989.
Presents the results of the remedial
investigation
-------
Date of
Publication
June 1989 U.S. EPA. Reporter's Transcript of
Proceedings Phoenix-Goodyear Airport Area
Superfund Site Final Remedy. Prepared by
Brush and Terrell, P.C. June 21, 1989.
This is a transcript of the proceedings
of the Public Meeting held by EPA on
June 21, 1989, at 7:00 p.m. in the
Goodyear Community Center to discuss the
PGA final remedy.
July 1989 Unidynamics Phoenix, Inc. Letter from
William Donahue to Mr. Jeff Rosenbloom, U.S.
EPA, including attachments. July 17, 1989.
Discusses technical issues associated
with the EPA preferred alternative for
the northern portion of the PGA site in
the vicinity of the Unidynamics
facility.
August 1989 Unidynamics Phoenix, Inc. Letter from
Michele B. Corash, Counsel to Unidynamics to
Hugh Barroll, Esq. and Jeff Rosenbloom, U.S.
EPA, including attachments. August 1, 1989.
Discusses legal issues associated with
the EPA preferred alternative for the
northern portion of the PGA site in the
vicinity of the Unidynamics facility.
August 1989 U.S. EPA. Memorandum from CH2M HILL to EPA
and the PGA Project Committee, including
attachments. August 24, 1989.
This memo includes an estimate of the
mass of VOCs in the vadose zone and the
estimate of migration of VOCs from the
vadose zone to the groundwater.
A-9
RDD/R94/029.50
-------
Date of
Publication
August 1989
August 1989
September 1989
September 1989
Unidynamics Phoenix, Inc. Letter from
Michelle Corash, Counsel to Unidynamics
Hugh Barroll, Esq., U.S. EPA. August 25,
1989.
Discusses ARARs for the PGA Superfund
site.
State of Arizona. Letter from Linda Pol-
lock, Assistant Attorney General to Hugh
Barroll, Esq. and Jeff Rosenbloom, U.S.
EPA. August 30, 1989, including an
enclosure.
Response to Unidynamics discussion of
ARARs for the PGA Superfund site.
U.S. EPA. Memorandum from CH2M Hill to
EPA, including attachments. September 7,
1989.
This memo presents responses to the
Unidynmaics technical comments submitted
July 17, 1989.
U.S. EPA. Memorandum to the file, includ-
ing attachments. September 22, 1989.
This memorandum is a response to legal
issues regarding the PGA Record of Deci-
sion.
September 1989 Record of Decision.
Currently
being
updated
CH2M Hill. Technical Data Management II
computerized data base located in CH2M
Hill's Phoenix and Redding offices.
Contains all water elevation and quality
data from ADHS, potential responsible
parties, and EPA sampling. 1981-present
A-lO
-------
The following items are not included in the Administrative
Record File since they are included in the "Compendium of
CERCLA Response Selection Guidance Documents" located at EPA
Region IX headquarters at 215 Fremont Street, San Francisco,
California 94105.
Sept. 1984
October 1985
Sept. 1986
October 1986
December 1986
U.S. EPA. Health Effects Assessment
Documents. ORD, OHEA, ECAO.
September 1, 1984.
U.S. EPA. CERCLA Compliance with Other
Environmental Statutes. Porter, J. W.
Office of Solid Waste and Emergency Response.
October 2, 1985.
U.S. EPA. Guidelines for Exposure
Assessment. Federal Register. September 24,
1986, page 34042.
U.S. EPA. Superfund Public Health Evaluation
Manual. Office of Emergency and Remedial
Response. October 1, 1986.
U.S. EPA. Interim Guidance on Superfund
Selection of Remedy. Porter, J. W. Office
of Solid Waste and Emergency Response.
December 24, 1986.
Date of
Publication
May 1987
May 1987
July 1987
April 1988
U.S. EPA. Final Guidance for the
Coordination of ATSDR Health Assessment
Activities with the Superfund Remedial
Process. Porter, J. W. OSWER, OERR,
ATSDR. May 14, 1987.
U.S. EPA. EPA's Implementation of the
Superfund Amendments and Reauthorization
Act of 1986. Thomas, L. M. May 21, 1987.
U.S. EPA. Alternate Concentration Limit
Guidance Part 1. ACL Policy and Information
Requirements. Office of Solid Waste, Waste
Management Division. July 1, 1987.
U.S. EPA. Superfund Exposure Assessment
Manual. Office of Emergency and Remedial
Response. April 1, 1988.
A-11
RDD/R94/029.50
-------
May 1988 U.S. EPA. Interim Guidance on Potentially
Responsible Party Participation in Remedial
Investigations and Feasibility Studies.
Porter, J. W. Office of Solid Waste and
Emergency Response. May 16, 1988.
June 1988 U.S. EPA. Community Relations in Superfund;
A Handbook (Interim Version). Office of
Emergency and Remedial Response.
June 1, 1988.
August 1988 U.S. EPA. CERCLA Compliance with Other Laws
Manual. Office of Emergency and Remedial
Response. August 8, 1988.
None U.S. EPA. Integrated Risk Information System
(IRIS). Office of Health Effects Assessment.
A-12
RDD/R94/029.50
-------
Appendix B
RESPONSE SUMMARY
-------
Appendix B
RESPONSE SUMMARY
PHOENIX-GOODYEAR AIRPORT REMEDIAL
INVESTIGATION/FEASIBILITY STUDY (RI/FS)
OVERVIEW
EPA received comments during the public comment period for
the June 1989 Draft RI/FS report. The public comment period
was held from June 7 through July 7, 1989. Comments were
received from state agencies, potentially responsible
parties, and members of the community. EPA also received
comments at the Public Meeting held on June 21, 1989, at the
Goodyear Community Center. All comments received are
responded to herein.
COMMENTS AND EPA RESPONSES
COMMENTS FROM ADEQ
Volume I
1. CHAPTER 2. PAGE 2-27. PARAGRAPH 3
In order to be consistent, provide the sampling depths
for the results for Sludge Bed No. 2.
RESPONSE
The sampling results and depths for both sludge beds
are presented in Figure 2-11 on page 2-29.
2. TABLE 2-8
The soil volumes calculated in this table differ signi-
ficantly from the volumes calculated by ICF Tech-
nologies, Inc., in the Chrome Sludge Drying Bed Feasi-
bility Study. How were the volumes calculated? Prov-
ide a page of calculations or a description of the
methodology utilized.
RESPONSE
Appendix K of PGA RI/FS details the methodology used to
derive the soil volumes presented in Table 2-8. Only
the EPA RI soil data were available at the time this
B-l
RDD/R226/026.50
-------
estimate was prepared. ICF Technologies, Inc.,
collected additional samples as part of their work at
the sludge drying beds. They used this additional
information to calculate their volume estimates. The
only volume presented in the chrome sludge bed FS is
for the soil contaminated above ADHS levels. ICF esti-
mated this volume to be 4,800 cubic yards for soils
above the chromium level. The estimate in the RI/FS is
2,200 cubic yards.
3. CHAPTER 2. PAGE 2-51. PARAGRAPH 6
Is there a possible explanation for the anomalously
high value for cadmium in boring 21-EP-3?
RESPONSE
There could be a number of reasons for the cadmium
value, but explanations at this point would be purely
speculative. Data gathered during the RI suggest that
outside of the area around the former sludge drying
beds, cadmium is not a problem.
4. CHAPTER 2. PAGE 2-62. PARAGRAPH 4
Please describe the sanitary wastewater bed. Has it
been referred to before? Is it the same as the exist-
ing wastewater ponds, or the sludge drying beds?
RESPONSE
The sanitary wastewater bed is an existing facility on
the former GAG property. It is labeled as the waste-
water sludge bed on Figure 1-7, page 1-21.
5. CHAPTER 3. PAGE 3-32. TABLE 3-10
The table repeats starting with well (B-l-1)16AAB5
(GMW-8) to the end of the table.
RESPONSE
Comment noted. The repetition has been removed from
the table.
B-2
RDD/R226/026.50
-------
6. CHAPTER 3. PAGE 3-40. FIGURE 3-11
Carbon tetrachloride has been identified as a contam-
inant in the groundwater and in concentrations exceed-
ing SDWA/MCLG. Should it be included in this table?
RESPONSE
Carbon tetrachloride is the seventh entry on the table.
7. CHAPTER 3. PAGE 3-41. TABLE 3-12
The title should read "Applicable or Relevant and
Appropriate". The ARAR exceeded by chromium (total) is
the MCL not the MCLG.
RESPONSE
Table 3-12 is revised to reflect these changes.
8. CHAPTER 3. PAGE 3-94. PARAGRAPH 5
There seems to be a disagreement between statements
made here and on page 3-38, paragraph 5, as to the
amount of discharge contributed by the MFU during pump-
ing of well RID 5.6W, 3.5N.
RESPONSE
The amount of discharge contributed by the MFU during
pumping of the well is more accurately stated as 25
percent as it is on page 3-94. Refer to pages 0-547 to
0-567 in Appendix 0 for a complete discussion, includ-
ing the zones of water production, for well RID 5.6W,
3.5N.
9. CHAPTER 3. PAGE 3-110. TABLE 3-31
Table 3-3 indicates one well exceeds the ARAR TCE con-
centration of 5 ug/1 but is not included in this
listing.
RESPONSE
More than one well listed in Table 3-3 exceeds the ARAR
value for TCE. None of these are appropriate to
include in Table 3-31 since Table 3-31 is a listing of
wells with unknown screened intervals that exceed
detection limits for all contaminants. The information
B-3
RDD/R226/026.50
-------
presented in Table 3-3 is unrelated to information in
Table 3-31.
Volume II
1. CHAPTER 5. PAGE 5-16. PARAGRAPH 5
What constitutes "significant" groundwater contamina-
tion? If only one monitoring well exists in the MFU,
then how can a determination be made in relation to the
impact of the site on the MFU? A brief discussion of
the lack of data would clarify the statement that the
MFU is "believed" to be free from adverse impact by the
PGA site.
RESPONSE
The term "significant" as used here implies the contam-
ination is high enough to cause adverse environmental
or public health impacts or is above ARARs. The cur-
rent data available on the MFU are limited, but include
information from wells other than just the monitoring
well. See pages 3-100 to 3-105 for a discussion of the
MFU data gathered during the RI. It is not anticipated
at this time that remedial actions for this unit will
be required.
2. CHAPTER 5. FIGURE 5-1
Inconsistencies exist between this figure and the sup-
porting text for identification and screening of tech-
nologies for soils. Typographical errors are common in
this figure.
Biological treatment as a remedial technology has been
screened out, yet the figure indicates that it is
potentially viable. An additional comment to support
the decision to drop the alternative from further con-
sideration would be beneficial.
The figure indicates that removal of soils is poten-
tially viable but the alternative is not discussed in
the text.
RESPONSE
The typographical errors are corrected on the figure.
The figure correctly shows biological treatment as
being screened out. The screening comments are changed
B-4
RDD/R226/026.50
-------
to reflect that biological treatment is not a proven
technology for use with the contaminants present at the
site. The excavation technology is retained for fur-
ther analysis and is discussed in Chapter 6 in the de-
velopment of alternatives.
3. CHAPTER 5. FIGURE 5-2. GROUNDWATER END USE
RECHARGE/REINJECTION — .
In accordance with the Environmental Quality Act, Title
Section 49-243.B.2 and 3, subsurface and surface dis-
charges cannot degrade an aquifer that is protected for
drinking water use. Since the Environmental Quality
Act protects all aquifers for drinking water use
(A.R.S. Title Section 49-224.B.), treated water would
be required to meet drinking water standards or aquifer
water quality standards prior to recharge or
reinjection. Further, if the water is reinjected or
recharged offsite (outside the study area boundaries)
then an Aquifer Protection Permit/Groundwater.Quality
Protection Permit will be required for the activity.
DISTILLATION & EVAPORATION
Any additional comments supporting the screening out of
distillation and evaporation would be helpful.
RESPONSE
Tr reinjection is part of the selected remedy, then the
Appropriate treatment levels will be required. Pages
5-32 and 5-34 expand on the reasons behind the screen-
ing of the distillation and evaporation option.
4. CHAPTER 5. PAGE 5-23. PARAGRAPH 5
Also note that if the treatment alternative results in
increased concentrations of constituents (i.e., higher
IDS), then the treated water could not be re-introduced
to the aquifer. (In accordance with A.R.S. Title
Section 49-243.B.2 and 3, the aquifer cannot be
degraded with respect to aquifer water quality
standards.)
RESPONSE
The paragraph states that no degradation of aquifer
quality is acceptable.
B-5
RDD/R226/026.50
-------
5. CHAPTER 5. FIGURE 5-3
In order to meet the substantive requirements of the
Aquifer Protection Permit/Ground-water Quality Protec-
tion Permit Program, in-flow and out-flow meters might
be required on the system to measure and record quan-
tities of treated water.
RESPONSE
These items may be included during the remedial design
phase. No change to Figure 5-3 has been made.
6. CHAPTER 5. PAGE 5-28. PARAGRAPH 3
Could air-stripping result in a waste stream from
accumulation of scaling deposits or from precipitate
formation? If so, this could be an added disadvantage.
RESPONSE
The text does refer to the possibility that cleaning of
scaling and/or deposits may be required. This would
likely create a waste stream requiring disposal but the
nature of the waste stream and the problems associated
with disposal cannot be predicted without actual field
operating experience.
7. CHAPTER 5. PAGE 5-28. PARAGRAPH 5
Is the handling of spent carbon prior to disposal or
regeneration a potential hazard? Would the material be
regulated by the Resource, Conservation and Recovery
Act (RCRA) (See #14)?
RESPONSE
Handling of spent carbon could present a hazard and
would require the same health and safety procedures as
handling of other hazardous wastes. However proper
design can minimize the handling required. The spent
carbon would be regulated under RCRA since it would
contain a listed hazardous waste.
8. CHAPTER 5. PAGE 5-31
Capping alternatives are broken down into costs. Why
wasn't the same approach used for the treatment
alternatives ?
B-6
RDD/R226/026.50
-------
RESPONSE
Capping is not discussed on page 5-31. Page 5-31 dis-
cusses treatment technologies for groundwater. No
costs are given in Chapter 5 for any technologies.
Chapter 6 provides relative costs for all alternatives.
Order-of-magnitude cost estimates for the alternatives
are provided in Chapters 7, 8, 9, and 10.
9. CHAPTER 5. PAGE 5-31. PARAGRAPH 3
Does bed backwashing generate a waste stream? If so,
please discuss the possible ramifications.
RESPONSE
Backwashing may be required if suspended solids in the
influent w<*ue» are high enough to build up over the
life of the carbon bed such that they plug the bed
prior to exhausting the carbon capacity. Backwashing
of the bed is usually avoided if possible either
through careful sizing of the bed or through installa-
tion of a separate upstream filter.
Any suspended solids collected would be a waste stream
requiring disposal. Generally, the suspended solids
would consist of clay and silt particles which may or
may not retain detectable quantities of contaminants.
The disposition of the waste cannot be determined
without actual field operating experience.
10. CHAPTER 5. PAGE 5-37
It seems reasonable to combine reverse osmosis with
other treatment methods to remove chromium.
RESPONSE
Chromium concentrations can be reduced using reverse
osmosis and other treatment techniques; however, there
is no apparent need to treat chromium at the site above
and beyond the Section 16 Operable Unit Remedial
Action.
11. CHAPTER 6. PAGE 6-25. PARAGRAPH 3
This section evaluates chemical-specific ARARs. Do any
action- or location-specific ARARs apply to potential
remedial actions for groundwater? (For example,
B-7
RDD/R226/026.50
-------
remedial actions performed "onsite" are only required
to satisfy the substantive requirements of permits.
If, however, water were to be recharged outside the
study area boundaries, then the CERCLA permit exemption
would no longer apply and an Aquifer Protection
Permit/Groundwater Quality Protection Permit would be
required for the activity.)
RESPONSE
There are action- and location-specific ARARs for all
__~ \ the potential remedial action alternatives. A complete
. ' " ' evaluation of ARARs appears in Appendix I. Only- the-
chemical-specific ARARs are discussed on page 6-25
since they are pertinent to the discussions defining
target areas which follow in Chapter 6,
12. CHAPTER 7. PAGE 7-8. PARAGRAPH 2
It would be expected that the estimated total mass of
VOCs in the soils for Target Area 2 should be greater
than that for Target Area 1 and less than Target Area
3. Is the 104,400 pounds correct?
RESPONSE
Page 7-8 of the Public Comment Draft RI/FS is the back
of Figure 7-3 and has no text. Page 7-18 of a previous
draft (Project Committee Draft, March 1989) contained
an error in the estimated mass of VOCs present in
Target Area 2. This error was corrected, but estimated
masses of VOCs for each target area were not included
in the Public Comment Draft. This was done since the
total estimate of VOC mass in the vadose zone is being
revised based on discussions with the PGA Project
Committee. Revised mass estimates will be distributed
to the project committee when they are available.
13. CHAPTER 7. PAGE 7-16. PARAGRAPH 6
Are carbon regeneration facilities subject to RCRA or
Air Quality regulations?
RESPONSE
Generally, Superfund sites are exempt from obtaining
permits for operation within the site boundaries; how-
ever, they must comply with the substance of the law.
B-8
RDD/R226/026.50
-------
Offsite discharges do require that all necessary per-
mits and regulations be obtained.
Specifically, any onsite carbon regeneration facility
would need to comply with the provisions of RCRA if the
spent carbon were determined to be a listed hazardous
waste, as is expected, but would not need to be per-
mitted as a TSD facility. Any air emissions from the
facility would have to comply with all federal, state,
and local air quality regulations and would also have
to meet all permitting and monitoring requirements.
14. CHAPTER 7. PAGE 7-28. PARAGRAPH 2
The ponds should be examined to determine if leakage
and infiltration are occurring regardless of the soils
alternative selected.
RESPONSE
The area around the former sludge drying beds, includ-
ing the ponds, is being considered separately for reme-
dial action. Goodyear Tire and Rubber is conducting
that work. It is agreed that pond liner integrity must
be assessed regardless of the remedial action chosen,
and that the ponds may have an effect on the sitewide
soils and groundwater remedial actions. Therefore,
there is a strong interest to determine that the ponds
are not leaking and allowing infiltration. These con-
cerns have been expressed to Goodyear during review of
their chromium sludge bed FS.
15. CHAPTER 7. PAGE 7-44
Should this be labeled as Table 7-9 not 7-1?
RESPONSE
Yes. Table number is revised.
16. CHAPTER 7. TABLE 7-8 AND 7-9
Capital costs calculated in Table 7-9 are not the same
as those listed in Table 7-8. Why do these differ?
RESPONSE
Capital costs listed in Table 7-9 are only the esti-
mated construction costs. Table 7-8 lists the total
B-9
RDD/R226/026.50
-------
capital costs which include construction,
mobilization/demobilization, permitting and legal, bid
and scope contingencies, services during construction,
and engineering and design costs.
17. CHAPTER 8. FIGURES 8-10. 8-12. AND TABLE 8-2
Calculations of rates of aquifer restoration to ARAR
concentrations indicate remedial action Alternative 4
is more effective than Alternatives 5 and 6 which
utilize more wells. This suggests that the location of .
the new extraction wells has more of an impact on the
clean-up time than the number of wells.
RESPONSE
Alternatives 5 and 6 were developed for the restoration
of the aquifer to background concentrations. This
requires extraction of a larger volume of water than
required to restore the aquifer to ARARs. The wells
considered in Alternatives 5 and 6 were placed to
achieve capture of this larger volume of water. The
figures show that Alternatives 5 and 6 are effective
for the ARAR target area, but not as effective as
Alternative 4, which was developed specifically for
restoration of the aquifer to ARARs. It is not appro-
priate to draw conclusions about extraction impacts by
comparing Alternatives 5 and 6 to 3 and 4 since they
were developed for different target areas.
18. CHAPTER 8. PAGES 8-40. 8-41. TABLE 8-6
TIME UNTIL PROTECTION IS ACHIEVED
The time required to reduce the contaminant levels in
the aquifer to below ARAR concentrations for Alterna-
tives 4, 5, and 6 is incorrect. Table 8-5 and Figures
8-10 and 8-12 indicate time is 38, 65, and 40 years,
respectively.
RESPONSE
Table 8-6 has been revised to correct the typographical
error.
19. CHAPTER 8. PAGE 8-4. TABLE 8-6
PERMANENT AND SIGNIFICANT REDUCTION OF TOXICITY,
MOBILITY, OR VOLUME
B-10
RDD/R226/026.50
-------
The above comment applies to this table as well.
RESPONSE
Table 8-6 has been revised.
20. CHAPTER 9. TABLE 9-10
How were flow rates derived for Alternatives 3 and 4
for contamination greater than background?
RESPONSE
There are no flow rates presented for Alternatives 3
and 4 for contamination greater than background.
Alternatives 3 and 4 are developed for the contamina-
tion above ARARs target area only.
21. CHAPTER 10. PAGE 10-12. PARAGRAPH 5
What is EBCT?
RESPONSE
EBCT refers to Empty Bed Contact Time which is a
design parameter for liquid phase activated carbon
vessels.
22. CHAPTER 10. TABLE 10-11 AND TABLE 10-12
These tables appear to be incomplete. Often no com-
ments appear for Alternatives 4, 5, 6.
RESPONSE
The tables will be revised to include comments for the
other alternatives.
23. APPENDIX J. PAGE J-3. FIRST EQUATION
The term should be 2S-X not 25-x.
RESPONSE
The term has been revised.
B-ll
RDD/R226/026.50
-------
24. APPENDIX R. PAGE R-AA. PARAGRAPH 3
Figure R-3 does not show TCE or chromium concentrations
as referenced.
RESPONSE
The figure has been revised to shew the areas.
25. APPENDIX S. PAGE S-29. PARAGRAPH 2
Where are Figures 9 and 10?
RESPONSE
Figures 9 and 10 are included on pages 24 and 25 of
Appendix S.
26. APPENDIX S. PAGE S-68
Upon examination of Figure 43, it appears that carbon
capacity at a TCE concentration of 920 ug/1 and a tem-
perature of 185 degrees Fahrenheit is greater than 10
percent by mass.
RESPONSE
While the graph is subject to interpolation error, it
appears that the 8 percent by mass capacity referred to
in the text on page 68 is approximately correct.
27. APPENDIX S. SUB-APPENDICES B & C
The Summary of Pressure and Flow Measurements and the
Summary of Concentration Measurements are not labeled
with page numbers. This makes reference to the tables
and data difficult.
RESPONSE
Page numbers will be added to the appendixes in the
final RI/FS.
B-12
RDD/R226/026.50
-------
COMMENTS FROM E. A. WOOTON
If carbon absorption is used to clean the fouled water
placed in and around Goodyear, then:
o What is to be done with the polluted carbon
material?
o Where is it to be stored to eventually corrupt
that area?
o What is the "life" of this pollutant before nature
neutralizes it?
Ic would appear that the Soil Vapor Extraction will pollute
the surrounding air of this valley.
o What amount of pollution will this method add to
the problems we already have in this area?
o As one who has asthma and is already concerned
about pollution, it seems to me that every effort
should be made to protect the citizens as com-
pletely as possible.
o Cost should not be the first concern.
RESPONSE
This comment appears to address two concerns. The first has
to do with the fate of any activated carbon that may be used
onsite. The second has to do with the disposition of the
vapor from the SVE system, whether it is treated, and any
possible health effects resulting from the discharge.
If activated carbon is used onsite, there are three possible
options for disposal of the spent material. The first is
landfilling. In this case, the spent carbon would be pro-
perly packaged and shipped to an approved disposal site
which is in conformance with all current restrictions on the
disposal of hazardous waste. Generally, this is only econ-
omical if small amounts of carbon are used. The carbon
would also be subject to EPA's land ban restrictions issued
under RCRA which may make this option unfeasible if the con-
centrations of contaminants exceed the limits imposed under
the regulations.
The second option is regeneration of the spent carbon.
This option entails removing the contamination from th
B-13
RDD/R226/026.50
the
-------
carbon so that the carbon can be reused. The contamination
that is removed is either recovered for reuse or destroyed
through incineration. This option could be implemented
onsite or offsite depending on economics and other factors.
The third option is incineration of the spent carbon. This
means the carbon and contamination are both destroyed in an
incinerator.
The alternative chosen will be protective of human health
and the environment and will depend on the quantity of car-
bon used, the concentrations of contaminant on the carbon,
and the relative costs of the options. An analysis to
determine the final disposition of the carbon would be done
as part of the design of the remedial action.
Soil vapor extraction as proposed in the RI/FS includes
installation of activated carbon to reduce emissions to the
atmosphere. The concentrations of contaminants at the out-
let of the two bed carbon units proposed will normally be
nondetectable. Thus, the health risk posed in the ambient
air by the soil vapor extraction unit will be negligible.
B-14
RDD/R226/026.50
-------
RESPONSES TO GOODYEAR TIRE AND RUBBER COMPANY'S
LETTER DATED JULY 6. 1989
(Letter attached at back of this appendix)
RESPONSE TO PAGE 2, 3RD PARAGRAPH
The June 7, 1989, Public Comment Draft RI/FS did contain
ADWR's model as Volume IX, Appendix V. Nonetheless,
Goodyear states they received the model in late May and they
will exercise their right to comment on it within 3 weeks of
its receipt. The 3 weeks expired prior to the date of their
letter.
RESPONSE TO SECTION ON "TCE RESIDUALS IN SOIL"
Goodyear states that the mass estimate for TCE in the vadose
zone is wrong for several reasons. It is agreed that the
method used to estimate the VOC mass in the soil is subject
to much uncertainty. Due to soil and contamination hetero-
geneities, the dynamic nature of transport phenomena in the
vadose zone, and the difficulty in defining the necessary
parameters, among other things, the calculation of mass in
the vadose zone will always be merely an estimate. However,
the Goodyear assertion that the mass is only 20,000 to
30,000 pounds is not accompanied by any calculations, so we
cannot assess its validity. The fact remains, based on soil
gas and soil data, that significant contamination continues
to reside _n the vadose zone.
Goodyear asserts that contaminant equilibrium is not
attained in the soil at the site but offers no reasons sup-
porting this conclusion. While the vadose zone conditions
will constantly change with varying recharge, barometric
pressure changes, temperature fluctuations, etc., the system
is likely to attain a rough equilibrium. The method used in
the RI/FS is the best estimate obtainable of those condi-
tions, and to our knowledge there is no reason to believe
that they significantly vary from equilibrium.
Goodyear asserts that the organic carbon fraction (foe) in
the soils and therefore the partition coefficient Kd should
both be 0.0 since apparently ADWR used this value in its
model. The foe used in the mass estimate is based on the
average organic fraction actually measured in soil samples
from the site. These data are shown in Table B-l of
Appendix S of the RI/FS. The value is not 0.0 but approxi-
mately 500 mg/kg. It should also be noted that while use of
this value increased the total mass in the vadose zone to
B-15
RDD/R226/026.50
-------
some degree, it also reduces the effect of recharge by esti-
mating contaminant retardation.
It is agreed that the best approach to vadose zone
remediation is to formulate a plan for evaluating the field
conditions as they are encountered. The problems that this
approach creates relate to the residual level of contamina-
tion that is acceptable (how clean is clean?) and how do you
.measure them. This decision will also relate to the target
areas chosen for remediation. The decision tree offered by
Goodyear is a good start but leaves several questions
unanswered relating to prediction of the threat of residual
contamination and the measurement technique used to deter-
mine compliance. Goodyear also states that drawing contam-
ination up from the groundwater is an undesired result from
the SVE system. Since removing contamination from the PGA
site is the desired result and the SVE system will
accomplish this, it is difficult to see why drawing contam-
ination from the groundwater into the SVE system is
undesired.
RESPONSE TO SECTION ON "GROUNDWATER"
Goodyear inaccurately restates the groundwater pumping
alternatives. Page 8-13 of the Public Comment Draft RI/FS
includes a description of the pumping alternatives
evaluated. None of the alternatives include pumping of
existing wells at an accelerated rate. Pumping rates for
existing wells are based on annual average pumping rates
obtained from ADWR records.
As presented in Chapter 8 of the RI/FS, the alternative that
considers pumping at an average rate from only existing
wells is ineffective at meeting the remedial response
objectives.
The Subunit A remedy will not eliminate contamination in
Subunits B and C.
The fact that the ADWR model was not used to evaluate the
groundwater alternatives does not mean that the evaluation
is "flawed." See the responses to technical comments
Numbers 12 and 14 for further discussion on this issue. The
techniques used for determining the hydraulic head in the
aqi'^fsr for various alternatives are based on valid and
accepted hydrogeologic formulas.
B-16
RDD/R226/026.50
-------
Reinjection is not the only end use considered. An entire
chapter of the RI/FS deals with alternative end uses for
treated groundwater.
Goodyear also presents data in support of installing air
stripping without vapor phase carbon treatment on the over-
head air stream. While these data will be factored into the
decision regarding treatment of the air effluent, they are
not the only data that must be considered. Other factors
include SARAs mandate on reducing contaminant toxicity,
mobility, and volume, other public comments regarding-the
site, and the air quality in the Phoenix area-", which is cur-
rently a non-attainment area for ozone precursors such as
those emitted by the proposed air strippers.
B-17
RDD/R226/026.50
-------
ATTACHMENT A TO GOODYEAR TIRE AND
RUBBER COMPANY'S LETTER DATED JULY 6, 1989
TECHNICAL COMMENTS
1. PAGE 2-37
The discussion of metals in soil encompasses all metal
data generated regardless of the probable source of the
metal or background levels in the area of the PGA.
This discussion is particularly misleading with respect
to arsenic since natural arsenic levels are
sufficiently high to generate risk levels of concern
and there is no record of use of arsenic onsite. The
failure to segregate site-related contaminants from
naturally occurring ones results in soil ingestion
risks being driven by arsenic which cannot be remedied
since it is ubiquitous in the native soil. A few
statements to this effect would prevent the reader from
being misled about site-related risks.
RESPONSE
It seems appropriate to include all data generated dur-
ing the RI in the RI/FS report. Pages 2-40 through 2-
54 include discussions of site-related contaminants and
background concentrations for contaminants. These
pages should eliminate any confusion about site-related
risks.
2. PAGE 2-40
No attempt has been made to differentiate Cr(III) from
Cr(VI) or leachable chromium from fixed or insoluble
chromium. As a consequence, total chromium values are
reported and used for the purposes of estimating public
health impacts even though availability and valence
state greatly affect the nature and magnitude of risks.
RESPONSE
Appendix G contains results of some sequential extrac-
tion tests done on samples containing chromium in
excess of background levels.
As stated in the endangerment assessment, risks were
calculated conservatively by assuming that all of the
chromium was Chromium VI. However, in areas outside
the former sludge beds (which are the areas of concern
B-18
RDD/R226/026.50
-------
in this FS),-even this conservative approach yielded no
significant health risks. The areas in and around the
former sludge beds are being handled by Goodyear under
an Administrative Order on Consent and were not
included in this RI/FS. Calculating risks for the
soils considered in this FS based on Chromium VI values
(which will not exceed total chromium values) will only
shown a smaller risk, but the risk has already been
shown to be insignificant.
3. PAGE 2-54
.An estimate of the inventory of TCE in soil of 450 Ibs
was made from existing soil boring data. When an
amount equal to this was removed during pilot soil
evacuation work, a second estimate was attempted using
soil vapor data. The latter estimate came to as much
as 115,000 Ibs depending on the assumptions made with
respect to vertical distribution of TCE residuals. The
algorithm used to calculate total soil TCE mass from
soil vapor data relies on an assumed equilibrium condi-
tion between soil-sorbed TCE, water-bound TCE, and soil
vapors.
For simplification, a single partition value was used
to calculate soil/water ratios. This value was also
used in conjunction with the Henry's law constant to
predict soil/vapor ratios. The partition value
selected was based on a prescribed soil organic level.
Use of any value other than 0.0 contradicts the assump-
tions made by the Arizona Department of Water Resources
(ADWR) in preparing the groundwater model for the site.
While the ADWR assumption is probably overly conserva-
tive, an assumed constant value throughout a 60-foot
depth is also misleading. It is highly likely that
deep sands and gravels will have little or no affinity
for the TCE. Hence, use of the algorithm will over-
predict soil-bound TCE from the existing TCE vapor
data.
The likelihood of overprediction is illustrated by ana-
lysis of the existing data. The highest soil vapor
values were found in the area of the soccer field.
Borings in that same area revealed no measurable TCE in
subsoils. Hence, the algorithm is assigning TCE at
significant concentrations to soils that have no
evidence of contamination. Similarly, soil vapor read-
ings from the area of the Phillips well were as high as
1.7 ug/1 even through this property is 3 miles from the
B-19
RDD/R226/026.50
-------
site. These vapor levels are either derived from other
sources or reflect the groundwater plume at that point.
There is no evidence that they are associated with soil
contamination.
RESPONSE
As stated previously, there are shortcomings to the
method used to predict the total TCE mass. Actual soil
data confirm that the organic content fraction in the
soil is lower than the assumed average at depth but
also that it is higher than average at the surface.
The assertion that this makes the prediction less
accurate is not clear.
It also is true as alluded to in the comment that soil
gas readings can be an indicator of a groundwater plume
as well as an indicator of a soil contamination source
area. However, any presence of contaminants in soil
gas is an indication of environmental degradation
however small. It should also be noted that sampling
and measurement of soils for the presence of
contaminants is subject to error through excessive
handling and volatilization. Only upon reviewing the
data in total can a determination be made of source and
nonsource areas and a prediction made of the
effectiveness of remedial action.
4. PAGE 2-61
Calculations are made to estimate the total volume of
soil in excess of Arizona Department of Health Services
(ADHS) soil action levels. These volumes are meant for
use in determining the cost of remedial action. The
volumes are misleading, however, since they encompass
all soils and subsoils with VOC concentrations in
excess of the action level. The action level was
devised for surface soils, not deep subsoils. Most TCE
residuals lie 20 to 30 feet below the surface.
Alternate action levels are needed for these soils on
the basis of their ability to affect groundwater
quality.
RESPONSE
To our knowledge, the ADEQ action levels are health-
based but apply to all soils and are not restricted as
to the depth over which they apply. While a
determination of which soils are a threat to
B-20
RDD/R226/026.SO
-------
groundwater is a good way of defining target areas,
this is difficult in practice. The target areas in the
RI/FS were chosen as a means of defining order-of-
magnitude costs. At this time, target areas for soils
remediation are under discussion and are likely to
change from those in the RI/FS prior to issuance of the
ROD. ...
5. PAGE 2-61
Vadose zone calculations are made suggesting that
16,000 Ibs of TCE will move to the groundwater in 20.
years. These calculations are based on an assumed
recharge that is without documentation. They also
appear to take no recognition of unsaturated zone
transport times. Using EPA time-of-travel algorithms,
recharge at 0.32 in/yr would take 117 years to move 20
feet downwind under current conditions. If the TCE has
a partition coefficient of 0.49 I/kg, its travel time
would be retarded by a factor of 2.6 and hence would be
304 years.
RESPONSE
Recharge is estimated based on our knowledge of annual
precipitation, ambient temperatures, estimated evapo-
transpiration, and runoff. The fact that contaminants
have in fact traveled through the vadose zone to the
groundwater is evidence that some recharge occurs at
the site. 0.32 in/yr was chosen as a reasonable esti-
mate but it is only an estimate. Currently, the
leaching of contaminants to the groundwater table is
being recalculated and the time over which recharge
occurs will likely be revised.
6. PAGE 3-46
The risk calculations are based on current TCE
concentrations at various wells around the PGA site.
No attempt was made to use the ADWR model to see how
those concentrations will change over time. Since can-
cer risks are based on 70 years of exposure, the
assumption is tantamount to saying that the groundwater
at any one well will not see any appreciable change in
TCE concentrations over a 70-year period. That is
unrealistic. Simple application of plume size and the
estimated velocities in the affected aquifer suggest
that concentrations will drop an order-of-magnitude in
7 years. If that does occur, the actual risk at the
B-21
RDD/R226/026.50
-------
site will be one tenth that predicted in the RI/FS.
The analysis also fails to consider the effects of the
Operable Unit 16 "remedy which is currently under
construction.
RESPONSE
"Pages R-139 and R-140 in Appendix R discuss the risks
for various scenarios under the no action alternative.
Future concentrations under the no action alternative
were estimated by ADWR with their model. The Section
16 OU remedy was included.
7. PAGE 3-46
Well logs from construction of extraction and injection
wells for the Operable Unit 16 remedy suggest that the
boundaries between Subunits A, B, and C are not always
distinct and then in some areas, the units may be
indistinguishable. Previous descriptions imply rather
clear cut interfaces which is misleading.
RESPONSE
CH2M HILL is willing to assist Goodyear in interpreting
well logs and serve as a resource of hydrogeologic data
which has been compiled over the last 5 years.
8. PAGE 4-1
Risk estimates for suspended particulate are based on
current emission rates being sustained over a 70-year
period. A simple calculation shows that in a period of
7 years, the finer suspendable particles will be
depleted to a depth of 1.5 cm. This in effect will
leave the larger, nonsuspendable particles to armor the
surface and minimize further resuspension. As a conse-
quence, risks will actually be an order of magnitude
less than predicted. The bulk of the risk from sus-
pended particles is attributable to arsenic in the
soil. Since arsenic is naturally present and not a
site-related contaminant, the risk calculations provide
a misleading picture of incremental risk and risks that
can be addressed by a site remedy. All soils in the
area pose the same level of arsenic driven risk.
B-22
RDD/R226/026.50
-------
RESPONSE
The risks were estimated using the most conservative
scenario. No backup is given for the calculation show-
ing a depletion of finer particles in 7 years, but data
from soil samples show silt contents of 60 to 70
percent in surface soils.
The bottom line is that risks calculated using the con-
servative approach are not significant for the soils
considered in this RI/FS; therefore, using a less con-
servative approach will not change the conclusions.
9. PAGE 5-41
The ultraviolet-ozone oxidation process is dismissed
prematurely. Recent studies show this process to be
very effective in removing organic contaminants from
water. In areas where air stripper emissions must be
treated with carbon, the UV-ozone process can be cost
competitive.
RESPONSE
To our knowledge UV-ozone type treatment has not been
proven commercially for treating halocarbons such as
those found at the site. In addition, the relatively
high TDS levels may make this option unattractive. In
the presence of a proven low cost alternative such as
air stripping, use of a new technology is unwarranted
without further study.
10. PAGE 6-13
Target Area 1 is inappropriate. ADHS action levels
were designed to address surface soils, not subsoils 20
to 30 feet beneath the surface. If a target area is to
be defined using ADHS action levels, it should be based
solely on TCE concentrations in surface soils.
Target Area 3 is not based on any defensible rationale.
No attempt is made to relate soil vapor concentrations
to site risk values. Since soil vapor results do not
correspond with subsoil concentrations of TCE, the use
of soil vapor to delineate a target area is illogical.
At a minimum soil vapor values should be converted to
equivalent soil concentrations and the target area
defined on the basis of the latter.
B-23
RDD/R226/026.50
-------
RESPONSE
The ARAR analysis identified a lack of cleanup criteria
or standards to be applied to the contaminated soils in
the vadose zone. In the absence of ARARs or other cri-
teria, EPA is to select a cost-effective remedial
action that meets the remedial response objectives,
unless meeting the objectives is not feasible. To
allow the selection of a cost-effective action, a range
of action levels was evaluated and the costs and -bene-
fits of each were identified. Target Area 1 was devel-
oped based on the ADHS action levels and is considered
the area containing the most significant amounts of
contamination at the site. Target Area 3 is considered
to be the area encompassing all contamination in the
vadose zone as a result of site-related activities.
11. PAGE 6-21
The discussion of the capping alternative appears to
contradict other portions of the RI/FS. The
implication of this discussion is that recharge is
insignificant with respect to TCE movement. And yet,
the calculations of vadose zone movement and soil
residual 'effects on groundwater quality are based on a
prescribed recharge rate of 0.32 in/year. Either
recharge is driving TCE downward and capping will mini-
mize or prevent this migration, or recharge is insigni-
ficant and subsoil contamination can be left in place
without remedy.
RESPONSE
The implication of this discussion is that the existing
paved areas are not adequate caps. A properly designed
cap will minimize infiltration and leaching of
contaminants.
12. PAGE 8-2
A very simplistic analysis is employed to calculate
aquifer flushing times. This is difficult to explain
since a great deal of money has been spent developing a
sophisticated groundwater model to predict flushing
times and plume movement. The RI/FS should rely on
model results for flow and transport predictions.
B-24
RDD/R226/026.50
-------
RESPONSE
In our opinion, the analysis performed in the FS is
appropriate for the task of developing and evaluating
conceptual alternatives for the project. The goal of
the analysis is not to predict the actual times for
flushing the aquifer of contaminants but rather to
evaluate the relative difference in flushing times
between the several alternatives. Evaluation using the
solute transport model developed by ADWR would cost
considerably more than the method used but would not
provide any additional accuracy in prediction of the
rate of flushing. This is because the model does not
account for the slow rate of flushing from the aquifer.
Rather, the model assumes that contaminants move in
piston flow. This assumption results in the inaccurate
conclusion that the aquifer is flushed after only one
pore volume is extracted.
13. FIGURE 8-3
The contaminant plumes have been depicted as large
areas joining points wherever VOCs were detected in
groundwater without regard to the relative
concentrations at adjoining wells. Geostatistical
analysis should be used to prepare these plots. The
relatively high values at the Phillips well and lower
concentrations at points between Phillips and the site
open the possibility of multiple sources or a more con-
centrated transient plume that is passing by Phillips
to be followed by water of better quality. Since risk
was estimated on the basis of continued exposure to
current levels, a better characterization of the actual
plume could have a big impact on conclusions concerning
risk and the nature of required remedies.
RESPONSE
The target areas for remediation are based on the
available data on the actual distribution of contamina-
tion in the aquifer. For the purpose of developing and
evaluating alternative remedial actions, it was con-
servatively assumed that the target areas should encom-
pass the entire are? that is bounded by observed
contamination in groundwater. It may be that the
actual distribution of groundwater contamination dif-
fers from the target area. However, without actual
field data showing that an area is clean, we believe
that it is appropriate to assume that it should be
B-25
RDD/R226/026.50
-------
included in the target. Geostatistical analysis of the
data is not reliable enough to reduce the size o£ the
target areas for remediating. After additional moni-
toring and extraction wells are drilled, modifications
to the target area for remediation can be developed.
14. PAGE 8-30
Simple equations are applied to estimate groundwater
travel times. The ADWR model was developed to provide
much more accurate predictions of travel times and
should be employed for that purpose.
RESPONSE
See response to Comment 12.
15. PAGE 8-36
A simplified approach is taken to calculate the time
required to achieve cleanup. Once again, the ADWR
model should be employed for this purpose.
Furthermore, the estimates do not consider implementa-
tion of the Operable Unit 16 remedy or continued inputs
from the vadose zone. This static evaluation of aqui-
fer cleansing is unrealistic.
RESPONSE
Additional evaluation of the impact of the vadose zone
in prolonging the cleanup is currently in progress.
These calculations suggest that if the vadose zone is
not flushed of contaminants, then the cleanup times
could extend for hundreds of years. In the evaluation
of the alternative in the FS, it was assumed that the
vadose zone would not be a continuing source of
contamination. Likewise, in the evaluation, it was
assumed that contaminants from Subunit A would no
longer be moving to Subunit C. This assumption impli-
citly includes to the Section 16 Operable Unit.
16. PAGE 9-7
The analysis cf end use options for the treated
groundwater -otsd not give ample consideration to
problems associated with water rights. A brief discus-
sion is given of water rights after discharge.
However, it is not clear if the water is currently
owned by a party who can subsequently dictate where the
B-26
RDD/R226/026.50
-------
treated water should go. If the City of Phoenix or
some similar entity owns the groundwater, they may not
allow it to be delivered for private or public use by
other entities. A much more thorough evaluation of
ownership is required before discharge alternatives can
be considered.
RESPONSE
The thorough evaluation of ownership and water rights
can be evaluated during remedial design. Presently,
the preferred alternative is to provide the water to
the current users of the existing wells. Additional
water from new extraction wells may be provided to the
City of Goodyear for municipal use.
17. PAGE 10-1
The options for design of the groundwater extraction
system should be evaluated using the available models
of the local groundwater. A simple water balance
approach fails to consider the Operable Unit 16 remedy
and the complexities of the aquifer. With
sophisticated tools readily available to support the
analysis, reliance on simple approaches is
inde fens ible.
RESPONSE
See responses to Comments 12 through 15.
B-27
RDD/R226/026.50
-------
COMMENTS EXPRESSED AT JUNE 21. 1989.
PUBLIC MEETING IN GOODYEAR. ARIZONA. AND RESPONSES
PAMELA SWIFT
I'm still very concerned about the health problems here and
of the employees that used to work here. So once again,
this is the fourth time they have been here and the fourth
time I've requested for health surveys. I do not want to
see air stripping because of our air quality laws. And even
if we didn't have that, when these chemicals are mixed with
other chemicals that are being emitted mostly at night from
our industries here, I think it's very dangerous. We do
have inversion here, so that's going to be very harmful if
there's any of the air stripping.
Also, since it appears that Goodyear and EPA has their mind
made up to go ahead with the air stripping, because it is
cost-effective, it's not health-effective, but it's cost-
effective — I would hope that they would put scrubbers on,
which I doubt if they will because scrubbers are very
expensive. But I do not want to see air stripping, and I
think it's going to be very dangerous for us to do that.
Thank you.
RESPONSE
Health surveys are typically conducted by agencies other
than EPA such as the Agency for Toxic Substance and Disease
Registry (ATSDR). Please contact Ms. Gwen Eng at ATSDR for
more information.
The air-stripping alternative for treatment of VOCs will be
well below all applicable air quality standards for
emissions. The current estimates are that approximately one
pound per day or less of VOCs will be emitted from the air
strippers. These low emission rates will be insignificant
to the ambient air quality, and no additional threat to
public health will be incurred.
If "scrubbers" or vapor phase emission controls are added to
the stripping towers, the treatment cost will be doubled or
tripled and an additional hazardous waste will have to be
dealt with. The activated carbon used to remove VOCs from
the airstream will require disposal or destruction through
incineration. Given the disadvantages of a significant
increase in cost and the required handling of a generated
waste, it is not feasible to add emission controls to the
B-28
RDD/R226/026.50
-------
air strippers which are already deemed protective of human
health.
MIKE BOONE
I'm for cleaning up the environment. I've lived in Arizona
all my life, and I'm very concerned about the environment.
I love the outdoors. And I think that we need to do all we
can to clean it up and for the future and for the present.
But I would be opposed to any type of emissions put into our
air unless you're certain that it won't affect the people in
the town of Goodyear and Avondale. Other than that, I think
it's a good plan, and I support it.
RESPONSE
See response to Pamela Swift.
DENNIS MYERS
F.A.A. will respond with written correspondence during the
allotted time.
COMMENTS FROM FEDERAL AVIATION ADMINISTRATION AND RESPONSES
1. During transportation of the contaminated soil, ensure
that the contractor(s) wet or cover the soil in the
vehicles to prevent wind blowing contaminated dust
toward the air traffic control tower (ATCT).
RESPONSE
If contaminated soil is transported, Department of
Transportation regulations will be followed to cover
the soil and mitigate dust.
2. Provide dust control for vehicle traffic south and west
of the ATCT on the unpaved roads and dirt areas.
RESPONSE
The surface soils are not contaminated except those
near the former GAG sludge drying beds which do not
receive vehicle traffic.
3. Brief Air Traffic Manager on any emergency procedures
and contingency plans concerning site cleanup.
B-29
RDD/R226/026.50
-------
RESPONSE
This can be done at the beginning of remedial
activities. Goodyear Tire and Rubber should perform
this task for the Section 16 remedial action.
4. We are concerned as to the locations of the air strip-
pers in relation to the ATCT, as we have an average of
seven employees on duty during a typical day shift,
working 75 feet above grade at the cab level and may be
exposed to high concentrations of VOCs. According to
your statement at the June 21 meeting in Goodyear, you
thought the air stripper towers would reach a height of
40 feet. Our employees would be 30 feet above that.
RESPONSE
Goodyear Tire and Rubber should address this concern
for the Section 16 remedial action. To determine the
exposure of employees in the tower from the air
stripping conducted during the final remedy, several
factors must be considered: treatment plant location,
emission rates from the stripping towers, and the
source of the air supply into the air traffic control
tower. More precise information concerning these fac-
tors will be gathered during the remedial design phase
and a more accurate assessment can be made at that
time.
B-30
SDD/R226/026.50
-------
AR:ZON-
OF WATEP
August 3, 1989 RESOURCES
Rcse Mc"0'2 3:
N W P'^nr-e'
Di-ec:of
Mr. Jeff Rosenbloom p-S^'i5;:^'
PGA Project Manager
US Environmental Protection Agency
Mail Code T-4-2
215 Freemont Street
San Francisco, California 94105
Dear Jeff:
Here is the responsiveness summary for the Three-Dimensional Contaminant
Transport Modeling Report otherwise known as Appendix V, Volume IX of the PGA
RI/FS report. I have received and addressed comments from the Arizona
Department of Water Resources and CH2MHILL. These are the only comments that
I have received at this time. The responsiveness summary follows the same
format as the responsiveness summary included in the Public Comment Draft of
the RI/FS report.
You will be receiving several quarterly reports to the present quarter by
the end of the month. If there are any other administrative tasks that need
to be taken care of for this site please let me know.
If you have any questions or need additional information, regarding the
responsiveness summary, please do not hesitate to call me at (602)542-1586.
Thank you.
With Best Regards,
Greg I. Bushner
Hydrologist
GB/rb
-------
RESPONSE TO WRITTEN COMMENTS RECEIVED ON
JUNE 1989 PUBLIC COMMENT DRAFT
REMEDIAL INVESTIGATION/FEASIBILITY STUDY
PHOENIX-GOODYEAR AIRPORT
Written comments on the public comment draft Volume IX were received from the
following parties:
o Arizona Department of Environmental Quality
o CH2M-Hill (Peter Mock)
Because of the wide variety of numbering styles used on comments submitted and
for ease in future references, the comments have been numbered consecutively,
from Comment No. 1 through Comment No. 80. All comments received which relate
to Appendix V - Three-Dimensional Contaminant Transport Model prepared by the
Arizona Department of Water Resources have been included in their entirety.
COMMENT 1 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Volume IX- ADUR 3-D Contaminant Transport Model
Overall, the report is thorough and well documented, however, the figures are
difficult to use. The maps showing locations of the facilities and wells are
not at the same scale as the maps showing the results of the various computer
runs. The addition of some reference points consistently used throughout the
figures would aid in orientation and interpretation of the results.
RESPONSE 1:
Comment noted.
COMMENT 2 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 44. Paragraph 2
The MFU and LCU probably do not significantly impact groundwater flow and can
be ignored in the water budget, however, the MFU is probably not a hydraulic
barrier to flow between units.
RESPONSE 2;
Due to the fact that the MFU within the study area is primarily
fine-grained, the vertical hydraulic conductivity within that unit is
probably very low, thereby, providing somewhat of a hydraulic barrier to
groundwater flow in to the MFU and LCU.
COMMENT 3 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 87, Last Two Points
Detectable concentrations of TCE have been reported for wells which produce
from the MFU
-------
RESPONSE 3:
For the purposes of the contaminant transport modeling the simplifying
assumption that the MFU is not significantly contaminated was necessary.
COMMENT 4 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 90. Last Paragraph
The last point is missing the verb "is" before the word "based".
Table 9 indicates that model input values for field parameters were varied
over a broader range during the sensitivity analysis than indicated here.
RESPONSE 4;
Comment noted.
Model input parameters were varied from one-tenth to 1370 times the model
input value rather than from one-ha'f to 1370 times model input values as
reported in the text. The values changed are as reported in Table 9.
COMMENT 5 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 97-99
Throughout this report, Unidynamics is -''scussed along with the airport and
GAC as a potential source of groundwater contamination at the PGA site. The
contaminant transport modeling does not address the plume beneath the Uni-
dynamics facility. An explanation as to *ny the model does not include the
Unidynamics plume may be appropriate here.
RESPONSE 5;
There are several reasons that the contaminant transport model does not
address the plume beneath the Unidynamics site. They are as follows:
1. The total extent of contamination in this area was not known
at the time the model was discretized. The framework for
the contaminant transport model was discussed in a
memorandum to the PGA Modeling Sub-Committee dated July 16,
1987.
2. Unidynamics is responsible for the entire RI/FS for their
site. The AOWR modeling study supports the EPA, who is the
technical lead responsible for the FS for sub-unit C of the
UAU beneath the Airport site.
3. Boundary conditions at the NE of the model domain were set
too close to accurately simulate the entire extent of the
plume in this area.
Although the plume beneath the Unidynamics site was not modeled, the data
that AOWR developed as a result of the modeling process was given to
Dames and Moore (groundwater consultants for Unidynamics) to assist them
-------
in development of their own model. All of the data collected by AOWR
benefited all parties involved at the PGA Site.
COMMENT 6 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 101. Table 11
Predicted TCE concentrations remaining adjacent to COG #11 well after 21 years
under Base Case 3 are higher for Alternatives 4, 5, and 6 than for the No-
Action Alternative (Alternative 1). How can this be? This does not seem to
agree with the figures of the model-predicted TCE concentrations for these
alternatives. In the figures, the model results are presented separately for
Subunit A and Subunit. B/C. Are the TCE concentrations in this table the sum
of concentrations from these Subunits?
RESPONSE 6:
The predicted concentrations for the City of Goodyear Well No. 11 for
Base Case 3 range from 1.1 ppb (No Action Alternative) to 5.8 ppb for
(Alternative 5). The relatively small rise in contaminant concentration
in Well No. 11 could be due to several variables including the proposed
FS wells, downgradient of the City's wells. These additional wells could
be pulling contamination further towards Well No. 11.
TCE concentrations reported in Table 11 are taken from layers
representative of the screened interval of the well.
COMMENT 7 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 106, Paragraph 2
Oc the proposed COG wells withdraw groundwater from Subunit A? Due to ambient
inorganic water quality, it is anticipated that the wells would produce from
Subunit B/C. Therefore, would the wells be expected to dewater Subunit A?
RESPONSE 7:
The proposed City of Goodyear wells are assumed to withdraw water from
sub-units B/C. The problem of the model dewatering near the western
model domain is a combination of (1) a groundwater flux out of the model
domain, (2) City of Goodyear's projected pumpage for 21 years, and (3)
the relatively small saturated thickness of the UAU in this area.
However, the proposed City of Goodyear wells would create a typical core
of depression as normally seen from other production wells in this
area. Therefore some dewatering from these wells would probably occur.
COMMENT 8 (ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY)
Page 174. Paragraph 2
Table 16 indicates the best reduction of contamination results frc~
Alternative 4. Is this statement regarding Alternatives 5 and 6 accurate?
-------
RESPONSE 8:
Comment noted, this statement is incorrect as Alternative 4 achieves the
best reduction of contamination than any of the alternatives including 5
and 6.
COMMENT 9 (CH2M-HILL)
General Comment (1)
The ground water flow model calibration did net 'isenefi: f^o- the jse of all of
the data, specifically the numerous water-level times series availaoie for the
area.
RESPONSE 9;
The water level data has not changed significantly during the past two
years. However, hydrographs will be incorporated in future model studies
of this area.
COMMENT 10 (CH2M-HILL)
General Comment (2)
Data on water levels are very sparse in an areal sense for the large modeled
area. This results in our not knowing which way the water flows in the
required detail over much of the modeled area. If we don't know, the model
surely can't. This makes the accuracy of calculated flow vectors and
concentration changes with time very suspect.
RESPONSE 10:
To the west of the airport, there is an area of contamination that we
felt necessary to include within the model domain. The problem dealing
with this contamination remains, regardless of the tool used to evaluate
it. The model predicts the groundwater flow direction reasonably well
given the current data available in this area of the site.
In an attempt to address the data deficiences that have been recognized
at the PGA site, AOWR proposed to collect additional hydrologic data
towards the western site boundary by installing additional monitoring
wells. This was proposed in the PGA committee meeting of December IS,
1986. This proposal was not acted upon. Until further hydrologic
information is gathered, a lack of adequate data will hinder modeling
efforts at this site.
COMMENT 11 (CH2M-HILL)
General Comment (3)
The report presents geologic and hydraulic interpretations different from
those we made in the RI/FS report. Some of these are large enough to make a
significant difference.
-------
RESPONSE 11;
Comment noted; comments regarding geologic and hydraulic interpretations
will be addressed under Ch^MH ILL'S specific comments that follow.
COMMENT 12 (CH2M-HILL)
General Comment (4)
Sensitivity analyses can give us a feel for the potential effects of uncer-
tainty on the predicted flow vectors and concentrations. Unfortunately, the
ADWR work didn't analyze the key parameters sufficiently (some not at all) and
didn't measure their results in such a way that we could benefit from what
work they did do.
RESPONSE 12:
Comment noted; comments regarding the sensitivity analysis will be
addressed under Ch^MH ILL'S specific comments that follow.
COMMENT 13 (CH2M-HILL) — - _ ' .
General Comment (5)
The predicted percent removals should not be treated as accurate engineering
estimates. Their use of the model for this pu^ose can not be supported on
the basis of the report or from what I reme^Qer the^ presenting to the
Committee.
RESPONSE 13:
I agree that the percent removals should not be treated as engineering
estimates, however they can be used to compare how effective the various
alternatives are relative to one another using different future
scenarios. I think it is fairly clear in the text that the percent
removals should be used as a guide and not as a definitive answer. This
was just one of the uses of the model, and as an investigative tool the
model can be supported by the report and by what has been presented to
the Committee as documented in the meeting minutes.
COMMENT 14 (CH2M-HILL)
P. 1. Par. 2
The ground water investigations (monitoring well installation, water quaint,
and water-level monitoring, aquifer testing, geophysical logging) were co--
ducted to support the development and evaluation of remedial action alte--
natives.
RESPONSE 14;
In the context of this report a detailed groundwater investigation med".
that geologic and hydrologic data was collected and analyzed from d"'
sources for support of the modeling investigation. This was done for -.--
-------
EPA in support of the Phoenix-Goodyear Airport Remedial
Investigation/Feasibil ity Study.
COMMENT 15 (CH2M-HILL)
P. 1, ^ar. 2
Sufficient information is not provided to evaluate the statement that a
reasonable match was achieved.
RESPONSE 15;
I disagree, sufficient information is provided in the report to evaluate
whether a reasonable match between simulated and observed parameters was
achieved.
COMMENT 16 (CH2M-HILL)
P. I, Par. 2
The sensitivity analysis as reported in this document did not explore the full
range of each parameter's potential value and impact on calculated heads,
local velocity vectors, and concentrations. Uncertainty was not quantified.
RESPONSE 16:
The sensitivity analysis did explore the t^e full range of reasonable
values for the reported parameters and the impact that changing these
parameters had on the calculated heads and local velocity vectors. The
uncertainty was qualified.
COMMENT 17 (CH2H-HILL)
P. 1, Par. 2
There is an inconsistency between the statement that order of magnitude
changes in horizontal hydraulic conductivity had little or no effect and the
statement that parameters such as horizontal hydraulic conductivity signifi-
cantly affected the flow model results.
RESPONSE 17:
The last sentence of this paragraph should be revised to read: 'Also
brought out . . . model results (i.e., horizontal hydraulic conductivity
of sub-unit C) ' . . . .
COMMENT 18 (CH2M-HILL)
P. 1, Par. 2
The qualitative evaluations of parameter certainty based on field data can re*.
substitute for a more rigorous analysis of model sensitivity.
RESPONSE 18:
-------
A more rigorous sensitivity analysis will be applied to the next phase of
numerical modeling at this site.
COMMENT 19 (CH2M-HILL)
P. 2, Par. 2
The implied accuracy of the predicted percentage removals of contamination is
not supported by the apparent problems encountered in applying the TARGET
model to contamination evaluations at this site.
RESPONSE 19:
Although percent removals of contamination are presented throughout the
report, they are intended to provide a comparative analysis of the base
cases and respective alternatives. As presented in the general comments,
they were never intended to serve as exact estimates of TCE removal given
the number of unquantif iable and unknown variables at this site.
COMMENT 20 (CH2M-HILL)
P. 6. Par. 2
The Blanket statement "The disposal of waste products at these facilities
occ-rred frorr, the late 1940' s until the 1970' s" is questionaole and probably
not something ADWR wants to say in its model study report.
RESPONSE 20:
statement is supported by the Source Verification/Field
Investigation Report by Ecology and Environment, 1986. Specifically
Taoles 2-1 (Waste Disposal Summary: Litchfield Naval Air Facility), 2-2
(Waste Disposal Summary: Goodyear Aerospace Corporation), and 2-4 (Waste
Oisposa1 Summary: Unidynamics/Phoenix, Inc.), list the waste types,
quantities, dates, and reported disposal practices. The statement is
true with the exception that disposal of solvents at the Hnidynamics
facility occurred between the late 1960's through the late 1970' s.
COMMENT 21 (CH2M-HILL)
P. 6, Par. 2
Data are not available to say that contamination does not affect the Middle
Fine-Grained Unit or Lower Conglomerate Units.
RESPONSE 21:
Comment noted. Information to date indicates that the significant
contamination has not yet affected the MFU.
-------
COMMENT 22 (CH2M-HILL)
P. 8. Bui. 5
This bullet indicates that the model study was to simulate the future response
of contaminants. Based on this, it would seem that the model study would
include predicting movement, not comparing percentage removal or clean-up
efficiency.
RESPONSE 22:
The bullet is correct as stated; Figures have been provided in the
Feasibility Study that show the predicted flow fields that illustrate
groundwater movement, and figures of plumes that illustrate the predicted
contaminant movement.
COMMENT 23 (CH2M-HILL)
P. 10. Par. 2
The statement that GAC retains liability for contaminated soils and ground
water at the site may be stronger than GAC has actually stated. This statement
may not be appropriate for AOWR to make in a model study Deport.
RESPONSE 23:
The intent of the statement was to indicate that tKe _ora: Corporation is
not a Responsible Party at this site even though i: o-ns tne property and
that the Goodyear Aerospace Corporation is one of the Responsible Parties
at this site. It was not intended to.offend or rcaxe a judgement of
liability at this site which is clearly outside o* the purview of ADWR
and this study.
COMMENT 24 (CH2M-HILL)
P. 11, Par. 1
Eberly and Stanley (1978) defined two units - Unit I and Unit II, not the UAU,
MFU and LCU. Also, work by the USGS and others indicates that the upper
portions of what has been called the MFU and the entire 'JAU may be Quaternary
tn age.
RESPONSE 24:
Comment noted.
COMMENT 25 (CH2M-HILL)
P. 11. Par. 2
Laney and Hahn (1986) address only the East Salt River Valley. The parallel
work of Brown and Pool (1989) for the West Salt River Valley is too recent to
be included in this model study. At any rate, the Laney and Hahn reference
should be explained as pertaining to another sub-basin.
-------
RESPONSE 25;
Comment noted.
COMMENT 26 (CH2M-HILL)
P. 11. Par. 2
The origin of the statements regarding the UAU's thickness, character, and
transition to the MFU is not explained. For example, refer to illustrative
cross-sections, isopachous, or percent-coarse mapping in this or other docu-
ments to which the reader can go to verify 'these statements.
RESPONSE 26;
The point is taken that the reader should have been informed of these
illustrations when they were first discussed. This section of the report
is intended as an introduction to the UAU. The reader is referred to the
rest of the section, which presents geologic cross-sections, isopach, and
structure maps.
COMMENT 27 (CH2M-HILL)
P. 11. Par. 2
I believe that this hydraulic conductivity estimate is an ensemble average of
estimates derived from the ADWR Drillers Log Program. Since use of this
program is relatively unique, it needs to be discussed when first referenced
and its accuracy compared to the more standard aquifer testing methods.
RESPONSE 27;
o
The hydraulic conductivity value of 750 gpd/ft was derived from an
analysis of driller's logs using the Driller's Log Program and specific
. capacity data. This information has been provided to the PGA Modeling
Sub-Committee in a memorandum dated March 11, 1987. The Driller's Log
Program was developed by ADWR personnel to generate aquifer parameter
data for areas that aquifer tests or specific capacity data were not
available. This program is used to calculate computer-generated values
for specific yield, hydraulic conductivity, and transmissivity. 'he
results obtained when using this program give a relative distribution of
the aquifer characteristics. The accuracy of the results are limited by
the quality, quantity, and distribution of the driller's logs within the
study area. This program has been used in several of the Department's
model studies including but not limited to the Salt River Valley
Cooperative Study Modeling Effort (Long et. al., 1982), and Groundwater
Modeling Study of the Upper Santa Cruz Basin and Avra Valley in Pima,
Pinal and Santa Cruz Counties, Southeastern Arizona (Travers and Mock,
1984). This program is a first cut at determining the aquifer parameters
in an area. It should not replace information derived from long term
aquifer tests. For the PGA site all available driller's logs were used
to evaluate the aquifer characteristics as reported in the above
mentioned memorandum to the committee. However, during the course of the
RI new aquifer parameter information was gathered and is used in
-------
conjunction with that derived by the driller's log program. Please refer
to Table 6, page 62 for the values used in the model.
COMMENT 28 (CH2M-HILL)
P. 11. Par. 2
The reference to Bouwer (1978) here and elsewhere in the text incorrectly
implies that a recognized authority supports a very narrow potential range of
vertical anisotropy for this particular site. The general nature of Bouwer1 s
suggested guidelines should be discussed when first referenced along with how
you applied those guidelines for this site.
RESPONSE 28:
Comment noted.
COMMENT 29 (CH2M-HILL)
P. 11. Par. 2
I disagree with the statement that the UAU is the water table aquifer in the
=GA area. My interpretation for the vicinity of PGA is that the UAU contains
zr.e water table aquifer (Subunit A), at least one confined aquifer (Subunit C)
ard at least one leaky aquitard (Subunit B). In fact, there is some field
ev'cence which indicates that Subunit A is confined in some areas. In
sjnrrary, the UAU is geologic unit defined on the basis of stratigraphy which
contains a system of aquifers and aquitards.
E 29:
Agreed, the UAU is a geologic unit defined on the basis of stratigraphy
which contains a system of aquifers. This description holds true for
act* the East and West Salt River Valleys. The UAU however, does contain
:ne water table aquifer within Sub-unit A.
COMMENT 30 (CH2M-HILL)
P. 12. Par. 2
The statement that Subunit A thickens at the basin margin should be tempered
by the recognition that the general driller's descriptions may not allow
precise distinction between the coarse materials of the UAU and LCU which may
tie in contact at the basin margin. Also the presence of the Gila River
trtdfcates that substantial reworking of LCU, MFU and UAU sediments would blur
the distinctions in this area adjacent to the Sierra Estrella.
RESPONSE 30;
Comment noted.
10
-------
COMMENT 31 (CH2M-HILL)
P. 12, Par. 2
If the horizontal and vertical hydraulic conductivities are not equal then the
statement should not be made that the average hydraulic conductivity is
isotropic.
RESPONSE 31:
It is stated that the average horizontal hydraulic conductivity is
assumed to be isotropic throughout the study area.
COMMENT 32 (CH2M-HILL)
P. 12. Par. 2
The use of the Drillers Log Program for estimating horizontal hydraulic
conductivity should be thoroughly explained and compared to aquifer testing
results.
RESPONSE 32:
Please refer to Response 27 above for an explanat'c* o^ the Driller's Log
Program.
COMMENT 33 (CH2M-HILL)
P. 12, Par. 2
The use of Bouwer (1978) as referenced here is again questioned for supporting
such a narrow potential range in anisotropy.
RESPONSE 33:
Comment noted.
COMMENT 34 (CH2M-HILL)
P. 12, Par. 2
A reference or method for estimating specific yield should be provided.
RESPONSE 34:
Specific yield values were derived using the Driller's Log Program and
from results of the aquifer testing completed on the site during the RI.
Please refer to the memorandum and attached maps sent to the PGA Modeling
Sub-Committee dated March 11, 1987 for further information. Also, refer
to Response 27 for further information regarding the Driller's Log
Program.
11
-------
COMMENT 35 (CH2M-HILL)
Figs. 3a-3c
The local cross-sections developed by CH2M-HILL in the Phase II Well Instal-
lation Memo and the regional cross-sections developed by CH2M-HILL in the RI
Report were available to AOWR prior to the release of chis report. The
subunit contact interpretations made by AOWR are different from those shown in
the RI/FS report. What alternate interpretations did AOWR make that led to
the development of additional cross-sections?
RESPONSE 35:
Many cross-sections were developed by ADWR during the RI (please refer to
the work products that were delivered to the Modeling Sub-Committee in
November 1984, and March 1985). The cross-sections included in the
modeling report are a combination of drillers logs (data from the
previous AOWR cross-sections) and geophysical logs from wells installed
as part of the RI. There can be many interpretations of the stratigraphy
in this area that are valid, which is why the logs are included in
Figures 3a through 3c. The cross-sections that CH2MHILL derived were
based on a simple percent fine and percent coarse material. ADWR based
their interpretations on descriptive drillers logs and the geophysical
information gathered during the RI. The information gathered by AOWR has
always been available to the committee, especially the drillers logs for
this area. The cross-section information, a'.so has been available to
the committee for inspection.
COMMENT 36 (CH2M-HILL)
Figs. 4a-4g
These maps are quite different from figures found in Chapter 3 of the RI/FS
Report which present the same titles. ADWR has interpreted different ele-
vations for the contacts between subunits and thicknesses of units than CH2M-
HILL has. Since the figures from the RI report were available to ADWR prior
to the writing of their report, what alternate interpretations did ADWR make
that led to the development of different structural contact and isopachous
maps?
RESPONSE 36;
Alternative interpretations are fairly clear throughout the report (refer
to Figs. 2 through 4, and Table 2 for the interpreted picks from the
available information). Each interpretation of the stratigraphy in this
report is adequate and serves the purpose for which it was developed.
COMMENT 37 (CH2M-HILL)
P. 25, Par. 1
The use of the Drillers Log Program for estimating horizontal hydraulic
conductivity and Freeze and Cherry (1979) for estimating vertical hydraulic
conductivity should be better explained and evaluated. How uncertain are
these methods and how do they compare to aquifer testing results?
12
-------
RESPONSE 37:
Please refer to response 27 above for an explanation of the Driller's Log
Program.
In the absence of field data, the values of "vertical hydraulic
conductivity for the various aquifers and aquitards within the study were
derived from a literature review or were assumed as stated in the report.
COMMENT 38 (CH2M-HILL)
P. 25. Par. 2
What methods were used to estimate specific yield and storage coefficient and
what accuracy bounds are appropriate?
RESPONSE 38;
Please refer to Response 34.
COMMENT 39 (CH2M-HILL)
P. 25. Par. 2
The discussions of Subunit C aquifer parameter estimates are questioned as
they *ere for Subunits A and B above. In addition, is the potential range in
val-e given for horizontal hydraulic conductivity based on the available data
or ^5 it some other type of estimate?
RESPONSE 39:
Please refer to Response 27; aquifer parameter estimates are based on the
available data as stated in the text and on Table 6, page 62.
COMMENT 40 (CH2M-HILL)
P. 25. Par. 2
The interpretations of subunit contacts and thicknesses described here are
different from those presented by CH2M-HILL in the RI/FS report.
RESPONSE 40;
Please refer to Response 35
COMMENT 41 (CH2M-HILL)
P. 26. Par. 2
Cross-sections or other presentations in this or another report should oe
referenced to allow the reader to verify the interpretations of the MFU s
extent and character.
13
-------
RESPONSE 41;
Comment noted. Please refer to Response 35.
COMMENT 42 (CH2M-HILL)
P. 26. Par. 2
.*
Are Montgomery and Associates estimates for horizontal hydraulic conductivity
locally derived? Would you expect them to represent the MFU as a whole or
would the hydraulic conductivity of aquifers in the stringers mentioned be
different? —
RESPONSE 42:
The reference of horizontal hydraulic conductivity is locally derived, as
noted in the referenced document. The value as reported in the
Montgomery and Associates report provides an idea of the aquifer
properties of the MFU near the study area. I would expect the hydraulic
conductivity estimates to vary through out the MFU.
COMMENT 43 (CH2M-HILL)
P. 26, Par. 2
The referenced value of vertical hydraulic conductivity from one test of a 6
foot section of a stratigraphic unit in another sub-bas'- should be viewed
with caution. What data do you have for the MFU in the PGA area that leads
you to believe that the estimates from the 6 foot interval in Scottsdale is
also representative here? The potential range in value for mis parameter in
any one location at PGA or Scottsdale is several orders of magnitude, not a
factor of 2 as implied here.
RESPONSE 43;
The reported value for vertical hydraulic conductivity was presented as
an estimate based actual field data from tests conducted in the East
Valley. The text is correct as stated in that the vertical
conductivities are not known with certainty and that the data reported is
from the East Valley.
COMMENT 44 (CH2M-HILL)
P. 27, Par. 1
References to presentations of data in this or other reports are needed to
allow the reader to verify these statements on the extent and character of
the LCU. Also, the entire sequence of alluvial fill (UAU, MFU, and LCU) may
be 10,000 feet in the basin center, but I doubt that the LCU itself is that
thick. I suggest you provide an authoritative reference for that.
-------
RESPONSE 44:
Please refer to Response 35. For further information the reader is
referred to the Central Arizona Project Geology and Groundwater Resources
Report Maricopa and Pinal Counties, Arizona, published in 1976 by the
U..S,. Department of the Interior Bureau of Reclamation Lower Colorado
River Region.
COMMENT 45 (CH2M-HILL)
P. 27. Par. 1
What potential effects could the pumping in the LCU have on the MFU and UAU?
Based on this you could explain why it is reasonable to disregard it in your
analyses.
RESPONSE 45:
Within the study area the majority of wells are perforated and with draw
water from the UAL). There are relatively few wells that withdraw water
from the MFU and fewer yet that withdraw water from the LCU. Since the
MFU is at least as thick as the UAU throughout most of the study area and
acts as a confining unit, the UAU would be buffered from much of the MFU
and LCU pumpage. Therefore it is reasonable to disregard the pumpage
from these lower layers.
COMMENT 46 (CH2M-HILL)
P. 27, Par. 2
The reference to Laney and Hahn (1986) should be explained as their report is
for another sub-basin. The existence and character of a unit that correlates
with the Red Unit of Laney and Hahn in the PGA area is presently unknown.
RESPONSE 46:
Comment noted. It should be stated that this reference is for a similar
sub-basin in the Salt River Valley.
COMMENT 47 (CH2M-HILL)
P. 28, Par. 1
I disagree that the three stratigraphic units can be characterized as three
distinct aquifers. It is my interpretation that each of the units describe:
in the PGA area contains systems of multiple aquifers and aquitards. '.
suggest you should revise the wording in this section which describes the l'A_,
MFU or LCU as "aquifers". The USER which developed the UAU-MFU-LCU nome--
clature used gross stratigraphy to define them. Therefore, they a'---
stratigraphic units, not hydrographic units.
15
-------
RESPONSE 47:
Although it is true that each of the stratigraphic units in the study
area can contain systems of multiple aquifers and aquitards, for the sake
of discussion and simplification of interpretation these aquifers and
aquitards are discussed based on the three main stratigraphic units (UAU,
MFU, and LCD) found within the study area.
COMMENT 48 (CH2M-HILLMOCK)
P. 28. Par. 3
Aquifers in Subunits B and C are under confined conditions as their upper
boundaries are below the head measurements made in them. This is based on the
definitions for confined aquifers given in Freeze and Cherry (1979). Bear's
(1979) definition would classify them as leaky confined aquifers.
RESPONSE 48:
Comment noted.
COMMENT 49 (CH2M-HILL)
Figs. 5a-6b
The point values are very -.ard to read on these figures.
RESPONSE 49;
Comment noted.
COMMENT 50 (CH2M-HILL)
P. 33. Par. 1
Heads in subunit B are commonly higher than in subunit C. The presentation of
figures 7a, 7b, and 7c together is misleading because only figure 7b includes
a well perforated only in subunit B. It is important to note that well GMW-2
in figure 7a and well UMW-5 in figure 7c are perforated in the top half of
subunit C, not in subunit B. Hydrographs from other well clusters with
subunit B wells provide a better demonstration of the head differences between
subunits B and C.
RESPONSE 50:
Comment noted.
COMMENT 51 (CH2M-HILL)
P. 33 Par. 2
Hydrographs from different key locations in the area are needed to support t-~
discussion of UAU history. I disagree that the UAU was "largely dewatered '.
I could accept the observation that subunit C was depressurized 40 to 50 fee:
16
-------
between 1945 and 1965. Even with a 40 to 50 foot drop in subunit C water-
levels, the difference in storage coefficients between subunits C and A would
likely result in a drop in the water table of less than ten feet which
certainly isn't largely dewatered. This water-level fall and subsequent rise
would have important consequences for contaminant movement. Such a discussion
would be appropriate here in the report.
RESPONSE 51;
The point is well taken that the UAU was probably not largely de-
watered. Unfortunately, the lack of high-quality data has prohibited us
from knowing exactly how the hydrologic system was behaving
historically. The information we do have as presented in figures 8a
through 8e gives us snap shots of the hydrologic system during specific
time periods from which inferences are made.
COMMENT 52 (CH2M-HILL)
Figs. 8a-8e
What can be inferred from the historical water levels and the presently
observed extent of contamination? This could be an aid to understanding the
long term ground water flow system and the movement of contaminants.
RESPONSE 52:
There is probably insufficient historic water level and -ater use
information to draw any type of conclusions regarding --storied'
contaminant migration. For this reason the model simulation, begins in
1978, when more data are available.
COMMENT 53 (CH2M-HILL)
P. 43 Par. 2
How do water levels in the waterlogged Gila River compare to UAU water levels
in the PGA area? Do they indicate if the Gila River gains or loses water in
this reach? What quantities of water could be gained or lost?
RESPONSE 53;
During the RI investigation and the preliminary groundwater flow modeling
by AOWR at this site many estimates were made of river recharge that
range from 0 to 46,500 af/yr as illustrated in Appendix A. Based on
current water level data it is very difficult to infer whether the Gila
River in this reach is a gaining or losing stream. More information is
needed to determine the interconnection between the Gila River and the
aquifer in this area.
17
-------
COMMENT 54 (CH2M-HILL)
P. 44 Par. 1
The data given in this section indicate that the vertical gradients across the
MFU maybe 5 to 15 feet per 300 feet of MFU thickness compared to horizontal
gradients of 15 feet per 5000 feet. This indicates that vertical gradients
are roughly ten times the horizontal gradients in the MFU. Near LCU pumping
centers, they could be even higher. The assumption of the MFU being a no-flow
boundary should address this observation.
RESPONSE 54;
The vertical gradient in the MFU may be greater than the horizontal
gradient however, the vertical conductivity values are much lower,
therefore the net flux is less. The MFU was assumed to be a no-flow
boundary for modeling purposes, that is simplification purposes.
COMMENT 55 (CH2M-HILL)
P. 45 T. 3
Does BIG concur with the estimated loss of over 6000 af/yr in this stretch of
their canal? Also, is there a variation in recharge over time that could
account for some of the observed water-level changes over a typical year? Ho'v
do you resolve the difference between the estimated and calculated changes in
storage? Do the indicated ranges in value include uncertainty in all of the
parameters used to calculate them?
RESPONSE 55:
The estimate of 6000 af/yr of water lost from the BIG canal was provided
by BIG personnel. There definitely could be much variation in recharge
over time that could account for some of the observed water-level changes
a within typical year. There could be a lot of variation in agricultural
recharge for example, however there is very little information from which
to base or revise estimates on. The difference between the water budget
change in storage and the calculated change in storage is probably within
the range of error of all of the data listed in Table 3. The residual is
within 25 percent of the overall inflows and outflows which is reasonable
given the data limitations for this area.
COMMENT 56 (CH2M-HILL)
Ffgs. lib, c
Where are the interpreted aquifer-aquitard or stratigraphic subunits located
art this grid? More importantly, is the grid fine enough to include observed
gradients of head and concentration?.
RESPONSE 56:
Unfortunately, re::^e time did not allow ^ny revisions to the text,
otherwise the first comment would have been incorporated. A 200 x 200
13
-------
foot grid in the horizontal plane and 30 foot in the vertical plane is
sufficiently fine to include observed gradients and concentrations.
COMMENT 57 (CH2M-HILL)
P. 56 Par. 1
The use of the assumed dispersivity to calculate the grid sizes may not be
adequate. The assumed dispersivity is quite large and recent work at the
University of Waterloo indicates that excessively large longitudinal dis-
persivities are commonly assumed for model studies. Instead, testing of the
grid for simplified conditions will indicate if it is of a size and orien-
tation necessary to simulate the observed gradients of head and concentra-
tion. No such testing is indicated in the report.
RESPONSE 57;
Usually the dispersivity values are determined as part of the calibration
process. This is accomplished by historically reproducing the
contamination with the model to arrive at the current plume configuration
and concentration. However, this was not possible given the data
limitations at this site. This has been clearly stated in the report.
The reportec c;spersivity estimates that were used provided reasonable
results as ::-ne out from the transport calculations and there was no
justification/ex Deducing these values.
COMMENT 58 (CH2M-H:LL)
P. 56 Par. 2
The derivation of the snecified flux boundaries is not discussed. Were they
varied with time? How were they distributed around the model domain? How
does the orientation of the rectangular boundaries with respect to flow affect
the distribution of fluxes?
RESPONSE 58:
The flux boundaries used in the transport model were based on previous
three-dimensional modeling by AOWR at the PGA site. The results from
this previous effort indicated that the flux boundaries did vary with
time and that they were distributed proportionally around the model
domain. The specified flux boundaries are admittedly not the best
condition for a groundwater flow and contaminant transport model. At the
time the target model was developed it was thought that rather than
expanding the model domain for several miles to include a hard rock
boundary, it would be more appropriate to use a flow net analysis to
determine the boundary conditions. This information is included in the
PGA files in the modeling section at ADWR and is available to interested
parties for review.
The orientation of the rectangular boundaries would have little impact on
the distribution of fluxes. In other words, even if the grid was
oriented north-south east-west the specified fluxes would have been
determined and distributed in the same manner.
19
-------
COMMENT 59 (CH2M-HILL)
P. 56 Par. 4
How well does the present model structure and boundaries match that of the
flow net and previous model? What is the uncertainty in the calculated fluxes
and their positions?
RESPONSE 59;
The present model structure is almost exactly identical to the
three-dimensional groundwater flow model. The main difference between
the two groundwater flow models is the use of the USGS MODFLOW code ard
that of the Games & Moore TARGET code. These two models handle boundar
conditions much differently and it was difficult to transpose the flu>
values from one model to the other.
There is a large uncertainty in the calculated fluxes and their exact
positions along the model boundary. However this uncertainty is
mitigated by the fact that the model reproduced water levels that comoare
with the observed field data.
COMMENT 60 (CH2M-HILL)
P. 58 Par. 1
If these recharge sources are so significant, how large is the uncertain:., "i
these estimates and how does it affect the calculated heads and more imrcr-
tantly, the local velocity vectors?
RESPONSE 60;
It is difficult to quantify the recharge estimates with precision,
however a potential range in values has been given in Table 3, page 45 in
the text, and Table 2 in Appendix A. Future modeling studies will try to
better address the uncertainty in these parameters. The heads will rise
or fall commensurate with an increase or decrease in recharge. Recharge
is assumed to be negligible at the airport property. Recharge due to
Agriculture is fa^'-ly evenly distributed and would therefore not have a
-eat impact on the local velocity vectors. Much of the uncertainty in
these values is mitigated by the fact that the model reproduced water
levels that compare with the observed field data.
COMMENT 61 (CH2M-HILL)
P. 58 Par. 2
What is the accuracy of the pumpage data? Are all significant wells included?
RESPONSE 61;
Pumpage data were either reported by the user or estimated by use of
power divider records. All significant wells within the contaminant
transport model domain were included (please refer to Table 5).
20
-------
COMMENT 62 (CH2M-HILL)
P. 58 Par. 1-2
The distribution of pumpage and recharge to individual grid cells is not
discussed. How does this affect local velocity vectors?
RESPONSE 62:
Pumpage and recharge estimates were distributed within the model domain
by overlaying the grid on the area of interest and determining the cell
in which the pumpage or recharge occurs. The distribution of these
parameters follow the real system as closely as the grid size allows.
COMMENT 63 (CH2M-HILL)
P. 62 T. 6
What methods were used to calculate these parameters? What are their poten-
tial ranges in value? What is the need for: specific yield of confined
units, TCE specific gravity, TCE viscosity - is this used in the model formu-
lation? If so, how? Wouldn't dispersivity vary with lithology? Given the
scale dependent nature of dispersivity, does the given value represent an
intermediate for projected growth of the plume or is it an initial value?
Finally, how do these values compare to the final model input values?
RESPONSE 63:
The sources of the data are clearly stated in the table. The sources of
these data are contained in AOWR files, complete with analyses.
Potential ranges in values were discussed in the text. The model
requires all of the input parameters listed except for transverse
vertical dispersivity which was erroneously included. Please refer to
the TARGET model documentation for a thorough explanation of these
values.
Dispersivity does vary with lithology, however it is beyond the scope of
the available data to determine how dispersivity varies within the study
area. The value of dispersivity appears to give sensible results.
These are the final model input values.
COMMENT 64 (CH2M-HILL)
P. 65 Par. 1
If the water levels are rising, the Gila River would become a gaining
stream. This may .explain the southwestern flow direction in Subunit A. Since
the river surface elevations are known, the model can allow flow into the
river when calculated ground water levels are above river levels. This could
provide local velocity vectors which are consistent with the real system.
21
-------
RESPONSE 64:
Comment noted. The model reproduces velocity vectors consistent with the
real system and may replicate discharge to the Gila in future years.
COMMENT 65 (CH2M-HILL)
P. 65 Par. 2
Why weren't the results of spinner-flowmeter surveys in eight productions
wells at PGA used to guide the vertical distribution of pumpage? Information
gathered from this program is considered more representative than estimates
based on drillers calls.
RESPONSE 65;
The information provided from the results of the spinner-flowmeter surve>
does not correlate from well to well and therefore can only be used tc
distribute pumpage in the well that the testing was done. Future
modeling at tiv's site may include the results of the spinner-flowmeter
surveys.
COMMENT 66 (CH2M-HI-L.)
P. 66 Par. 3
This logic would preclude the use of Agua Fria River recharge (Page 48, Table
4).
RESPONSE 66:
Agreed which is why Agua Fria River recharge is not included in the
model. The rate given in page 48, Table 4 was done so for completeness
and information.
COMMENT 67 (CH2M-HILL)
P. 68 Par. 2
Estimates of field scale dispersivity vary widely. The modeling should
account for this. Recent work suggest that large values are probably not
representative. What relation does dispersivity have to soil types?
RESPONSE 67:
The estimates for dispersivity values are based on a literature source as
stated in the text. Unfortunately there are no measured values for this
parameter at this site. Therefore, it was necessary and appropriate to
make this assumption. In addition, since calibrating the model to an
area and concentration of contaminant was not possible due to the lack of
historical source information, this assumption was the most appropriate
to make. It would not help to make up a variability in the dispersivity
estimates as suggested due to the uncertainty involved in the parameter
itself. The reference for dispersivity values is for alluvial sediments.
22
-------
COMMENT 68 (CH2M-HILL)
P. 69 Par. 3
The observed variations in concentration with depth could be used to guide the
distribution used in the model. It is possible that the assumption of full
vertical mixing of observed values is not conservative. The potential uncer-
tainty in the field data should be discussed because it relates strongly to
the usefulness of the model's output.
RESPONSE 68:
The observed variations in concentration with depth were used to guide
the distribution of the contamination in the model. I think the approach
taken was conservative based on the available data.
COMMENT 69 (CH2M-HILL)
P. 71 Par. 2
Because the simulation is transient and the area! distribution of head data is
sparse, comparison of model-simulated to the abundant measured hydrographs in
the area should have been the key criteria for flow model calibration.
RESPONSE 69:
Comment noted. Future modeling by AOWR at this site will include
calibrating to some type time-series analysis. However, it should be
noted that the abundant measured hydrographs are for very specific areas
near the RP facilities.
COMMENT 70 (CH2M-HILL)
P. 71 Par. 4
Were fine enough time steps used to benefit from the six-month breakdown in
pumpage?
RESPONSE 70;
Initial tests of time step sensitivity indicated that the time steps used
were fine enough to benefit from the six-month breakdown in pumpage.
COMMENT 71 (CH2M-HILL)
P. 73 Par. 1
Although the simulated gradients are said to be close to measured gradients,
inspection of figure 14a indicates that interpolation between data points
yields gradients near the Airport whicn are more than twice those simulate:!.
Large areas are present for which the local velocity vectors can not be dete"-
mined by visual inspection. Are the stated velocities for the center of mass
or the edge of the contamination? There is no clear demonstration that tie
model matches historical data.
23
-------
RESPONSE 71:
The stated velocities are representative of the flux in the areas of
contamination and are as noted in Table 8 on page 84. The model matches
the observed data as presented on Figures 14a through 15e and as stated
in the text. It is important to note that this model is the best tool
available to analyze the groundwater flow system in this area. Though
there are many data deficiencies within the study area these have been
recognized by the EPA, ADWR, and CH2MHILL since 1985. AOWR has suggested
that additional information be gathered in areas other than the RP's
however this has not been acted on. Therefore until more information is
collected the model is the best tool available.
COMMENT 72 (CH2M-HILL)
P. 84 Par. 1
The comparison of heads does not indicate if the local velocity vectors are
correct. What may seem like a close head match could result in local flow
directions which are 90 degrees or more in the wrong direction. This point is
critical to evaluation of the model estimates. The discussion in this para-
graph of the paucity of data for determining the goodness of fit only indi-
cates that we do not have enough information to determine if our model is
simulating the real system.
RESPONSE 72:
The equipotential lines as illustrated on figures 14a through 15e
indicate that the predicted flow directions near the RP facilities and
further due west of the facilities are consistent with historic and
present flow directions. There is no indication that the flow directions
are 90 degrees or more in direction opposite of what the simulated heads
represent. In simulating the RA's the model did a good job in predicting
local velocity vectors, (please refer to the figures in the Groundwater
Modeling Feasibility Study section of this report). It is true that
there is not enough information to the west of the RPs to determine if
the model simulates the real system.
COMMENT 73 (CH2M-HILL)
P. 85
See previous comment.
RESPONSE 73:
Please refer to Response 72.
COMMENT 74 (CH2M-HILL - PETER MOCK)
P. 86 Par. 2
Inspection of figures 14a through 14e indicates that the ground water model
flow calibration to the available head data is incomplete. Data are not
24
-------
available within enough of the modeled area to indicate what gradients and
local velocity vectors are present in the real system. Addition calibration to
the abundant measured head hydrographs in the area could be used to improve
the confidence in the ground water flow model calibration. We do not believe
that confidence can be placed in the model's prediction of gradients and local
ground water velocities.
RESPONSE 74:
Comment noted. Most of the abundant measured hydrographs referred to are
represented in Figures 14a through 15e. This data is localized in the
area of the RPs. Within the rest of the model domain, there is very
little information available to indicate what gradients and local
velocity vectors are present in the real system.
ADWR recommended in 1986 that additional monitor wells be installed to
gather more regional data within the study area. Additional data
collection is necessary to achieve the local accuracy referred to above.
However, since this was not done we have to live with a degree of
confidence based on the available data. The model is a useful
comparative tool, but is based on limited available data.
COMMENT 75 (CH2M-H!LL)
Figs. I6a, b
What is the uncertainty in these distributions?
RESPONSE 75:
There is mucn uncertainty in these distributions, however, this is the
best information we have. The text on page 97, paragraph 1 lists the
source of information for both the sub-unit A and B/C plumes.
COMMENT 76 (CH2H-HILL)
Table 9
The sensitivity analysis is incomplete because it does not run the model with
the full potential range in each parameters value. For example, hydraulic
conductivity could easily vary over several orders of magnitude. The
rationale for the selected variations used for analysis is not clear. Given
that the use of this model would be for contaminant transport, the variations
in the velocity field caused by uncertain parameters are of most critical
concern. It is not clear why the effect of variations was only observed on
calculated heads (especially porosity which probably is not included in hea,"
calculations). The percentage change in head during the simulation period- per
percentage change in the selected parameter provides a much stronger inc;-
cation of sensitivity. The sensitivity analysis time period should be as lc-:
as the expected projection time period for its results to be useful. --
expanded sensitivity analysis which includes variations in all uncerts--
inputs including recharge and boundary conditions would be required to fL''.
evaluate this model's usefulness for projections.
25
-------
RESPONSE 76;
Comment noted. This will be taken into consideration in future modeling
at this site.
COMMENT 77 (CH2M-HILL)
P. 96 Par. 1
The parameters critical to transport were not analyzed. If a parameter such
as dispersivity or porosity, is not measured or if it is poorly known, then
is even more critical that its potential effect on model results
evaluated. Sensitivity analysis is far from an academic exercise if i
importance is understood.
RESPONSE 77;
Please refer to Responses 67 and 74.
COMMENT 73 (CH2M-HILL)
P. 172
An evaluation of the model's projections was curtailed because of the id'-ge
uncertainties discovered in the ground water flow modeling and transpc-t
sensitivity analysis. The accuracy of the model's calculated velocity f^e':
and resulting contaminant concentration can not be even roughly guessed it
with the available information. The predicted reductions in concentrator
must therefore be viewed as one set of potential outcomes whose accuracy 's
unknown. A cursory examination of the projection runs indicates excessive
drawdowns near model boundaries and extensive movement of contamination t*a:
has not occurred to date. These observations call into question the ability of
the model to simulate the ground water flow system at PGA.
RESPONSE 78:
Comment noted. Please refer to Response 74.
COMMENT 79 (CH2M-HILL)
P. 172 Par. 2
We disagree with the statement that the results of the sensitivity analysis
indicate that acceptable confidence can be put into the ground water flow
model calibration results.
RESPONSE 79;
Comment noted. Please refer to Response 74.
26
-------
COMMENT 80 (CH2M-HIin
P. 174 Par. 3
While the model does provide a relative evaluation of the various ground water
remediation alternatives, the accuracy of that evaluation can not be estimated
with the information provided. Considerable sensitivity analyses on the model
with respect to uncertain transport parameters, numerical stability and the
model grid orientation and size would be required to develop some understand-
ing of the model's performance and accuracy.
RESPONSE 80:
Comment noted. Please refer to Response 74.
rb
27
-------
CRANE
UNIDYNAMICS/PHOENIX
UNICVNAMICSPHOENIX
POST OFFICE BOX 46100
TELEPHONE - (*» KB-DOO
TELEX —MT«M
TWX - 910-»5ftO«B3
FAX - «oa*B-»«»
PHOENIX. ARIZONA 85063^100
12 September 1989
SEP I S V369
CHaM HILL
Mr. Jeff Rosenbloom, Chief
Enforcement Programs Section
United States Environmental Protection Agency
Region IX
215 Fremont Street
Dear Jeff:
Enclosed is the response to comments you requested which were
prepared by our consultant, Dames & Moore.
Please call me if you have any questions.
Very truly yours,
HCD/dl
Enclosure
W. C. Donahue
Director
Human Resources
-------
5EP-1-1 -19S9 16:54 FROM
TO
•"SdSSW 1367775964=
Responses to Corps of Engineers
Page 1
COMMENTS BY TED STRECKFUSS,, ENVIRONMENTAL ENGINEER
Page 5-8 Include documentation substantiating the selection of a 100 ppb
level for a removal concentration in Subunit A.
Response: See our responses to ADEQ RI Comment 03 dated July 7, 1989, EPA
FS Comment 030 dated June 9, 1989 and Technical Comments dated
July 17, 1989.
Page 5-9 Document the selection of the 10,000 cfo gas flovrate to be used
in the air stripper. This flow rate appears to be excessive.
Response: See our response to CH2M Hill Comment #24 dated March 23, 1989.
COMMENTS BY JOHN E. SAKORE
General Comments; The preferred remedial alternatives proposed
Torsite remediation (Alternatives A-l and A-2) are not
supported by the analytical data presented in this draft.
Additional assays are needed especially at Waste Facility 91 and
building 19 areas* Conclusions reached throughout the draft are
often based on speculation.
Response: The comment does not provide support for its conclusion and is
not specific enough about the areas of disagreement Co allow for
specific rebuttal.
Page 2-11, 2.3.2.6 Building 19. Paragraph 2.
1. The groundvater beneath Building 19 contains more than
100,000 ppb. of Trichloroethene (TCE). Considering the Density
of TCE and the solubility of TCE in veter, there is probably a
layer of TCE present in the lover part of the Aquifer (Subunit
A).
Response: Comment noted, conclusion reached is not substantiated.
2. There is insufficient data to support the statement that
"Building 10 does not appear to be a source of VOC's to
groundvater based on the data collected*
Response: See our response eo EPA RZ comment 99 dated June 9, 1989.
Page 2-11, 2*3*2*7 Drum Storage Area
The open area to the north of Building 19 used to store empty
solvent drum* is nov bare which indicates that solvents could be
present in sufficient quantities to suppress the growth of grass
ia that area.
Response: The entire UPI facility is controlled to be purposely grass-free
with the exception of the front lawn near the reception area.
The no-grass areas are intentional and have been since 1963.
-------
-3EP-I1-1SS9 16=54 FROM
- *643a14156T7753S45
Responses to Corps of Engineers
Page 2
Page 2-16, Sentence #4
The conclusion that Wast* Facility li is the primary source
contributor of TCB to groundvater is Qoe supported by this
analytical data prc««nt«d.
Response: See our response to ADEQ RX comment 91 dated July 7, 1989.
Pag* 2-13i Paragraph 3
The analytical results on soil sampling indicate chat the high
Barium and Aluminum concentrations found need to b« fure-er
investigated. Although Aluminum was not reported as being : ?d
at the facility, the pond assay results (80,000 mg/kg) cannot >«
ignored.
Response: Comment noted.
Page 2-16, Sentence f*
The conclusion that the Waste Facility #1 is the primary source
contributor of TCB to groundvater is not supported by the
analytical data presented.
Response: See our response to comment regarding 2-16, Sentence 04.
COMMENTS BY DAVE BECKJR
Rl, Page 2-10
tov levels at various facilities do not necessarily suggest chat
Che facilities are net sources - look at lov levels at some
areas ae the GAC/Airport areas.
Response: See our response co SPA Rl comments 07 and ''3 dated June 9,
1989.
KX, Table 2.1
Were any analyses done for explosives and volatile propellent at
building 12?
Response: Building 12 is designated as Waste facility *?8. Table 2.3 and
2*4 of the RI reports that this facility was tested for total
metals within the sedimentation tank and for ?OC concentration
and total metals within the soil surrounding the sedimentation
tank* No other testing was performed.
RI, Page 3-18, last paragraph
MW-14 i« not really directly dovngradlent - more crossgradient -
this may impact the definition of contamination ia "C".
-------
SEP-11-1989 16=55 FROM
TO
*645914156777598^5
Responses
Page 3
Response:
Response:
Response:
Response:
Response:
to Corps of Engineers
See our response co CH2M Hill comment 48 dated March 23, 1989.
RI, Page 3-19, top paragraph
Can veil SF4A be a cross-contamination source? Should it be
replaced with a veil aot open eo "A"?
See our response to ADEQ RI comment #38 dattd July 7, 1939
RX, Page 3-20, 3rd to last line
Describing "B" as a barrier is Coo strong - it's a leaky
barrier*
See our response to EPA RI comment #13 dated June 9, 1989.
FS, Page 1-2, see 1.2.1
The RI did not characterize ground vater over 6 sq. miles.
The text states that the Unidynamics study area is approximately
six square miles. Separately, the text states that Che RI
characterized groundwacar and soil quality. To interpret and
combine these :vo sentences in the manner vhich this comment
does is incorrect.
F3, Page 2-14, 3rd paragraph
Dilution vill reduce VOC levels but increase volumes over ARARs
- may be foolish to vait!
See our legal comments dated August 1, 1989*
FS, Pag* 2-15, 2nd paragraph
Remember 2 possible sources of TCZ - TCE in vadose zone and
DKAPL ia saturated zone - Nothing is said about addressing
possible pure TCE at "A"/NB" interface. Either way, dilution
vould take a very long time considering levels at UPI.
Response:
Dilution and point-of-use treatment options address the
possibility that pure TCE may be present at the Subunic
A/Subunit B interface.
FS, Page 2-16, 1st full paragraph
Reference in 4th line of paragraph to current point of use is
misleading -the point is that you don't know vhere "points of
use" vill be in future.
-------
3EP-11-1989 16:55 FROM
*645a1d15S77759SU5
Response*
Pagt 4
•ss
Response:
Response:
Response:
Response:
Response:
Response:
co Corps of Engineers
Comment noted.
FS, Page 2-20, 3rd paragraph
Though no estimates of risk were aade - level of risk will
undoubtedly increase.
The comment does not provide support for the conclusion that the
level of risk will undoubtedly increase*
PS, Page 2-20, see 2.7.3.3
This section downplays risk too ouch.
The purpose of this section is to report the potential ri 3
arising froa exposure to on-site groundwater. This is done n
an objective manner using quantitative results. It cannot a
intimated froa any part of this section that the risks are
"downplayed".
FS, Pagt 3-7, 1st full paragraph
I disagree that "A" is a 111 aquifer - try lib.
o See our legal comments dated August 1, 1989.
o See "Guidelines for Groundvater Classification under the £?A
Groundvater Protection Strategy", December, 1986.
FS, Page 3-9, last line
Exposure pathways does not lead to risk levels greater than 10"4
now - but may if points of exposure change ia future.
Comment noted.
FS, Pagt 3-10, see 3.3.1.5
Exposure to toil is noc the impact of concern.- TCI in the soil
can continue to impact groundwater.
The primary concern associated with TCS contamination within the
soil is indeed if* potential impact on groundwater. However,
since tht possibility that exposure to TCE in the soil could
occur, a complete investigation of this possibility and its
ramifications vas performed.
PS, Pagt 3-13, last sentence
Disagree that the technological and permitting makes aquifer
recharge less desirable.
Response: Comment noted.
-------
5EP-1 1-1969 16=48 FROM
TO
P.-22
Response*
Page 5
Response:
Response:
Response:
Response:
Response:
Response:
Response:
to Corps of Engineers
PS, P«gt 3-18, 2nd paragraph
Disagree vich conclusions here.
See our legal comment* dated August I, 1989.
PS, Page 4-3
1st bullet - ... process in handling... What?
This statement is referring to the ability of the process co
reduce toxicity, mobility or volume of the contaminants.
FS, page 4-6
last bullet - SVE should be option without capping.
The comment provides ao support for its conclusion and cannot be
addressed.
PS, Page 5-6, last paragraph
Time for treatment will be very long especially if pure product
is present.
Comment noted.
FS, Page 5-9
Treatment to 100 ppb TC2 is probably not acceptable - how was
100 ppb chosen? I wouldn't think that assuming dilution with B
and C is acceptable way to meet A&AR.
See our responses to EPA FS comment #30 dated June 9, 1989; ADEQ
RI comment #3 dated July 7, 1989, and legal comments dated
August 1, 1989.
FS, Page 5-9, 2nd to last paragraph
Will the State let you pump veils for waste-? That's what you'd
be doing in going to sever.
There are serious and unanswered questions regarding che
implementability of this option. These are discussed in Chapter
5, pages 5-21 to 5-22 of the FS.
FS, Pagt 5-19, 1st full paragraph
GV-1 should be GW-3 (Also on page 5-21).
A typographical error occurred in the preparation of the tax;.
GV-1 should be GW-3 as" pointed out.
-------
14 15677755645'
Responses to Corps of Engineers
Page 6
P^, Page 5-21
Mention need Co limit and discharge of VOCs to 40 Ib/day as part
of implcocntability.
Response: We recognize that air emission limitations .nay be needed.
FS, Page 6-9, last sentence of cop paragraph
The logic here (not treating all water, only water used) is poor
vhea dealing with the levels you have in Subunit A*
Response: o The comment does not provide support for its conclusion.
o See our technical comments co SPA dated July 17, 1939.
FS, Page 7-3, 2nd paragraph
Uncertainties in contaoinant fate could be reduced if you dealt
vith the problea now.
Response: Comae at noted.
?S, Page 7-4
I disagree with technical logic behind recommended alternatives.
Response: This comment is not specific enough about che areas of
disagreement to allow for a response*
-------
SEP-Ii-1989 16:49 FROn
Response co G. Stephenson Comments
from City of Goodyear on Rl/PS
Page 1
TC
*64581415677739845
P. 24
70LUKE 8. CHAPTER 1 - RI COMMENTS
Page 2-3 Paragraph four* The conclusion presented regarding vasce
facility 4 i» not supported by the evidence given. "Ifa" a&d
"probably*" arc inaufficiane to eatablish a firm conclusion.
Response: See our response co EPA Comments dated June 9, 1989.
Page 2-11 Last paragraph, second sentence. "Some liquid*" .... Should
describe then or identify if possible.
Response: The identity of the liquid* is not known.
Page 2-16 La*c four bullet* require acre evidence than presented in chi*
chapter in order to make these conclusion*•
Response: o Third bullet: See our response to ADEQ comments- dated July
7, 1989
o Fourth bullet: See our response to EPA comment* dated June 9,
1989
o Fifth bullet: Comment noted
o Sixth bullet: See our response to ADEQ comment* dated July 7,
1989
Chapter 3
Page 3-9
First paragraph* Be more specific in gram size rather than use
of terms like "fine grained", etc* It i* important here because
of the controversy regarding possible groundvtter movement
betveen subunits. The gram size data i* surely available from
sieving of the drill sample*.
Response: o Drill samples were not sieved a* per EPA - approved drilling
program.
o A more thorough and detailed description of the UAU subunits
and MTU characteristics, including composition can be found in
Chapter 3, Vol. I (Public Comments Draft) of the RI/FS.
Page 3-19 Second paragraph. Mixing unit* - be con*i*tent. Use either ug/1
or ppb, noe both.
Response: Comment noted*
Page 3-19 third paragraph, last sentence* Data from the City of Goodyear
filet for the year* 1983-1988 would be better than Black &
Veatch, 1985. Average groundvater production for the city of
1983-1988 was 920 af/yr (City of Goodyear Water Use Reports,
1989).
-------
TO
. 1*6458-14.1567775=845 ' ' s. 35
3EP-11-1389 15=49 FROM
Response to G. Stephenson Comments
froa City of Goodyear oa RI/FS
Page 2
Response: Comment noted.
Page 3-19 Last paragraph. The City currently use* a total of 8 veils, not
6. Need to be more thorough about the location of Well #10. The
so-called "warehouse" currently employees 237 people and is
expanding* they expect to employ 80 more over the next tvo
years. Veil *10 is a sole source, sole supply for this facility.
City Veil No*. Z and 3 are both screened la Subunit C, and both
have recorded ICE concentrations as high as 6.8 ug/1 and 16.0
ug/1 respectively, this should be recognized here.
Response: o
The text states that the City currently has a total of 3
that supply the water distribution system.
••ells
o Comment noted regarding the warehouse.
o The text recognizes chat City Veil Nos. 2 and 3
detectable TCS concentrations.
ave
o See our response to the comment regarding pages 2-4, fourth
bullet, last sentence.
Page 3-20 First paragraph. Veil No. 10 is perforated in the upper part of
the Kiddle Fine Grained Unit (381'-578') as determined by a TV
scan by Gilbert Pump Company in August, 1984 (City of Goodyear
files).
Response: This information is already included in the text.
PS COMMENTS - CHAPTER 2
Page 2-2 Paragraph two* The site encompasses 35 square miles, not 25.
Litehfield Park is nee to the site- boundary. Except for the
Loral facility, and the Phoenix-Goodyear airport, and about 4
square miles of Avondale along the southeast part, the remainder
of th» site lies within the City of Goodyear.
Response: Comment noted.
Page 2-3 Paragraph tiro. Is Subunit B also a "water-bearing tone"? See
pcgt 2-11, third paragraph, where it is referred to as such.
Response: Although it is not explicitly stated at this point in Che text,
Subunic 3 is a water-bearing zone.
Page 2-4 First bullet, "hydraulic isolation'* seem* to be inappropriate
usage here* Simply because of a local change in gradient does
noe mean that regionally Che areas are not part of the same
system.
Response: The text does not imply that the two subareas are noc part of the
same regional system. . However, the text does point out that a
divide within this system has caused groundwater to flow in two
distinct directions leading to a hydraulic isolation of che
groundwater contamination within the two subareas.
-------
SEP-12-1389
11 = 20 FROfl
co vr« stepftenaon Comments
from City of Coodyear on RI/FS
'
TO - -645814! 5677759845
F. ;•?
.
Third balltt, last sentence* Rot tor* whet this aesna, buc it
can b« interpreted «• saying th« evidence it disputable. Would
two negative* aake it positive?
Response J While previous investigations have yielded iasighes into the
degree of interconnection between Subunita B and C, the exact
extent of this interconnection has not been established* Hence,
the statement "no indisputable" evidence refers co the
uncertainty regarding the evidence*
Fourth ballet, last sentence* This stateaent is wrong! City
Veil Ho. 2 recorded 8 ug/1 TCI OB 4/14/87 and No. 3 recorded 16
ug/1 TCE oa 10/9/87, Both are veil within the vicinity of UPI.
Response:
Page 2-6
o According to Chapter 3, Table 3.4, Vol. 1 (Public Cooaents
Draft) of the RI/FS, the highest detected concentration
recorded in City Well Nos. 2 and 3 is 6.8 ug/1.
o The iaplicstion of this coaaent seeas to be that sinc« COC
Well Nos. 2 and 3 lie within the general vicinity of UPI, the
facility is responsible for causing the elevated TCE
concentrations. However, ^generally known features of this
facility do not support this'conclusion. First, regular water
aeasureaents have not shown groundwater flow towards City
Veils *2 and '3. Furthermore, these wells sre located
cross-gradient to and outside of the known TCE conuam^aant
pluae and would not be affected by UPI activity.
Paragraph three. Use of the words "most solvents" iaplies chat
there are solvents not stored. How about those thst ;>re not?
What is done with thea? Use of "aose" snd "ooae" leaves the
iapression thst 49Z could be elsewhere. Reed to be aore sxacc in
your stataaent. The data support it.
-------
16:50 -
Response to 6* Stephenson Comments
from City of Goodyear on RI/FS
Page 4
Response: Solvents aoe stored ere chose solvents not replaced by SPA or
ADEQ. These are solvents vhieh are not listed under RCRA.
Page 2-8 Second paragraph. Unclear as co what the background
concentrations were.
Response: Background concentrations for aluminum, barium, arsenic, raercury,-
. lead, chromium and sine arc listed in Chapter 2, Table 2.10 of
the RZ.
Pagt 2-12 First paragraph* Absolutely ae supporting evidence to s« chat
uncertainty exists regarding connection betveen Subunics B d C.
The face that TCE is present io Subunie C is evidence en- h to
verify connection. The method of connection, either hydrau c or
via poorly constructed veils or both, may be uncertain.
Response: The text states that there is uncertainty regarding the dea^ «, of
interconnection betveen Subunits.3 and C. It does not state ;hac
there is uncertainty regarding connection betveen Subunie* 3 and
C.
Page 2-13 Last paragraph. Pee mean concentrations instead of average to be
consistent with Table 2-1* Table 2-1 has 179,000 not 180,000.
Response: Comment noted.
Table 2-1 Put note for units at top of Table* Cannot tell froa thee Table
vhieh units are A and vhieh are C unless the reader knovs aore
detail about the veils» A note stating 3, 6 and 10 are Subunit C
veils would help*
Response: The subunit in vhieh a particular veil is located can be
determined froa che heading "Aquifer" vhieh plainly states this
information.
Page 2-14 first paragraph. Be consistent when using average and mean.
Response: Comment noted.
Last paragraph and top of pagt 2-15. If contaminated groundvatar
ia Subunit C has noe moved off-site, hov do you account for
contamination la Subunit C off-site City Weila Not. 2 and 3?
Response: See response to comment concerning Page 2-4, Fourth bullet•
Page 2-16 Second paragraph, last sentence. The City is noe willing to
gamble aay longer on the faee that their, "supply veils are not
likely to be affected, if at all, for several years." Some are
already affected.
Response: Proposed remedial action would provide for well-head treaeaent of
city veils, if needed^ There would be no "gamble" on city's
part.
-------
SEP-11-19S9 16=51 FROM TO *64581415677759845 P.OS
Response to G. Stephenson Comments
from City of Goodyear on Rl/FS
Page 5
Page 2-18 First paragraph. There is too much conjecture in this entire
paragraph, which is not supported by evidence. Certainly,
conditions may change but projections must continue to be made.
The projections for growth have been made based on sound
planning. Granted, they are not absolute, but they are
predicated on a clean, adequate groundwater supply.
Response;
Page 3-7
Response:
Page 3-17
Response:
Comment noted.
First paragraph, last sentence. Remember that S.C. #4A is
screened from 140' to 685'; that is from mid Subunit B veil into
the MFU, and has recorded TCZ concentrations as high as 22 ug/1.
This would certainly indicate that the MFU i± affected adverselj
by the release of TCE at thi» site.
No veils have been screened exclusively in the MFU. Therefore,
1C is not possible to claim vith any degree of certainty chat the
MFU jL£ adversely affected by the release of TCZ at chis site.
The high level is most probably attributable to TCE contamination
present in subunit A.
Second paragraph, under Section 3.4.1. Nothing given to support
this. In fact, see above com&ent.
The comment is not specific enough regarding she area
disagreement vith the text.
of
Page 3-18 first paragraph, last sentence. How is this so when TCE _is_
recorded in Subunit C as you have noted previously.
Response: The comment is not specific enough regarding che area of
disagreement vith the text.
Page 6-5 First paragraph. The MCI for Subunit C has been exceeded.
Response: See our response to the comment concerning Page 2-4, fourth
bullet, last sentence.
-------
5EP-11-1989 IS:51 FROM
Response to ADWR Comments
Page 1
.*6~'J58 1 4 1 567'7''59845
. 39
GENERAL CONCERNS
The preferred remedial alternative for the Unidynamics site
allows for continued degradation of the drinking vater aquifers.
The uncertainty whether erichloroethene and other solvents will
migrate to the Subunit C aquifer is itself a reason to take a
conservative approach and implement remedial actions to prevent
contamination from migrating to the Subunit C aquifer, which
will include treatment of Subunit A.
Response: Comment noted*
Not enough information is available to discount contaminac :n in
the MFU at this time in the Superfund area*
Response: Nor is enough information available to speculate that the : I ia
adversely affected.
?eluae HI/RI
For each organic compound listed on the page, the minimum and
maximum concentrations should be stated along with their
frequency of detection*
Response: A listing of minimum and maximum concentrations for each
detected organic compound is more meaningful vhen it is
presented with the location at which this ainimum/aaxiauo
occurs. This information ia presented in Chapter 2, Table 2.7
and 2.3 of the RI.
Page 3-2, First Full Paragraph and Table 3.1:
The monitor well completion data for MW-1 through MV-4 is
missing from Table 3.1* This information needs to be included*
Response: See our response to ADEQ RI comment 430 dated July 7, 1989.
Page 3-16, Second Paragraph:
The Environmental Quality Act affirms that all aquifers in the
state arc classified for drinking water purposes.
Response: See our legal comments dated August 1, 1989.
Page 3-20, Second Paragraph; Reference: Map of Veil Locations
for Abendoned and Destroyed Veils (USGS and ADWR Records;
Prepared by CB2M-HXIL; Last Update, May 1988)t
Several abandoned veils exist within the plusM of organic
contaminants migrating from the Unidynamics facility. The
report fails to recognize that these wells may be acting as a
vertical conduit for contaminants to migrate from subunit A to
the lover aquifers.
-------
'5EF-11-1989 16=52 FROM
Response to ADVR Comments
Pagt 2
TO
#645814I56777598a5
P. 13
Response: Comment noted.
Pagt 3-21, Second Paragraph:
Tht reported hydraulic conductivity values in this paragraph do
not agree vith the reported values for transaissivities oa page
3-13 whtn using the reported saturated thicknesses as found in
section 3.2.1.2 on pages 3-6 through 3-8.
Response: Comment noted.
FS/Page 2-11, Second and Fifth Paragraphs:
The reported hydraulic conductivity values are not consistent
vlth vhat is reported in the Remedial Investigation Section of
this report.
Response:
Subunit A
Subunie B
Subunit C
Response:
Hydraulic conductivities are reported in the text at three
different locations: Chapter 3, page 3-21 of he RI; Chapter 3,
Table 3.5 of the RZ; Chapter 2, pages 2-10 to 2-11 of the FS.
These values (in gpd/ft^) are summarized below:
Page 3-21 (RI)
100-200
<30
600-UOO
Table 3.5 (RI)
50-120
798-1430
Pages 2-10 eo 2-11
120-220
14-100
280-340
Clearly, the above table shows that Subunit A and Subunie 3
hydraulic conductivity values are consistently reported. There
is a discrepancy between the reported RI values and che FS
value for Subunit C. The correct values for Subunit C arc those
presented in the RZ.
Page 2-12, first Paragraph:
Although tht interconnection between subunits A and C has not
been very well established ae tht UPI site, eht assuaption that
no contaminants vill migrate due eo a lack of information is not
appropriate. It is apparent that additional information is
needed eo determine vertical hydraulic conductivities and the
extent of tht interconnection between subunits A and C.
The text states that the degree of interconnection between che
subunits is uncertain* Because of this uncertainty, the rate of
migration of tht contaminants, and consequently, the long-cera
impact of TCI contamination on Subunit C, is unknown. The text
does not *ay that this uncertainty is reason to conclude chat n£
aigration will occur.
-------
5EP-n-l989 16 = 52 FROM
Response to ADVR Consents
Page 3
TO :;-••«6
-------
SEP-11-1989 IS=53 FROM
Response to ADVR Comments
Page 4
TO
*645ai413677759845
Response: See our legal comments dated August 1, 1989.
Page 3-7, Firtt Paragraph:
Please refer to comment 3*
Response: See our legal comments dated August 1, 1989.
Page 3-9, Top of the Page:
The MCL, ARAR, is five micrograms per liter for TCE in aquifers
designated as drinking water aquifers by the State of Arizona.
The Environmental Quality Act designates all aquifers in
the state as drinking water aquifers*
Response: See our legal comment$ dated August 1, 1989. Also see
"Guidelines for Groundwater Classification under the £?A
Croundvater Protection Strategy", December, 1986.
Page 3-11, ground-Water Withdrawal:
The right Co withdraw groundwetar would need to be obtained from
the Arizona Department of Water Resources*
Response: Under CERCLA, substantive compliance is required.
Page 3-11, Ground-Water Withdrawal. Paragraph I:
ADWR does not have authority to prevent the installation of all
wells, nor does it have ultimate authority in limiting the use
of water in any area.
Response: ADWR does have authority to regulate well construction standards
which could be used to eliminate groundwater use from specific
zones.
Page 3-11, fifth Paragraph:
Withdrawal of groundwater at the Unidynamics facility will
require e groundwater withdrawal right* ADWR considers a PQGV?
at a right to withdraw water and will require a PQGWP to be
obtained.
Response: It is our understanding that substantive compliance for a PQGWV?
la all that is required under the provisions of CERCLA.
Page 3-13, Surface Water Discharge;
The Phoenix Active Management Area will not permit this type of
end use as it is not consistent with the Groundwater Management
Act.
-------
5EP-11-1989 16:53 FROM
Response CO ADWR Comments
Page 5
TO *S4591415377-55845 - P.13
Response: Comment noted.
Page 3-18, Second Paragraph:
The ARAA or TBC conclusions of this paragraph hav* not been
supported aor approved by the agencies*
Response: See our lagal comments dated August 1, 1939.
Page 3-12, First Paragraph:
The statement chae the "No Action" or monitoring alt*, cive
would be sufficient to protect public health ia not apprc late
due to the uncertainties that exist in the current data
regarding tha extent of subunit C contamination and ver ical
permeability ettimatea. These data deficiencies shou. be
determined before anj remedial alternative ia chosen.
Response: The text recognises chat chere are several factors which vill
iapaet the long cera «ffactiveaeaa of chis option.
Specifically, Chapter S, Page 5-13, Section 5.3.11 of the ?S
Hcts these factors as:
o The extant of ICE migration into Subunic C
o Effects of development of additional groundvatar suppliaa and
its impact on fate and transport of TCZ in che groundvacer
system
o Vhether future walls will produce vater from Subunit C
o Effects of attenuation in Subunit C
This option incorporates groundwater aonitoring eo gauge :he
long term effectiveness of this option. Should drinking water
be threatened, the oonitoring network will provide early warning
and sufficient opportunity to take additional actions to prevent
huaan health from being endangered* la this way, public health
it protected.
Page 6-*, Long-Term Bffectiveneee:
The health risks might be controlled but it is not clear if they
would b« protective of human health and the environment* It is
highly uncertain that the impacts could be controlled.
Response: The comment does not provide support for its conclusion.
-------
CRANE
UNIDYNAMICS/PHOENIX ?GA
UNIOYNAMICS/PHOENIX • POST OFFICE BOX 46100 • PHOENIX. ARIZONA 85063-6100
2 Augu^c 1989
Mr. Jeff Rosenbloom, Chief
Enforcement Programs Section
United States Environmental Protection Agency
Region IX
215 Fremont Street
San Francisco, California 94105
RE: Response to ADEQ's comments - Unidynamics RI/FS Report
Dear Jeff:
Enclosed per your request are Unidynamics' responses to Arizona
Department of Environmental Quality's comments on our RI/FS.
If you have any questions, please contact me at 602/932-8245.
Very truly yours,
W. C. Donahue
Director
Human Resources
WCD/dl
Enclosures
xc: M. Corash
F. Stephenson
G. Seifert
T. Ungerland
1000 NORTH LITCHFIELD ROAD • GOODYEAR. ARIZONA 85338-1295
-------
Jv.eSpOr.Se ..w • •- v ~w—UW-.ILS ' _' " ;
dated July 7, 1989
Page 1 A;j;-
1. EXECUTIVE SUMMARY. GENERAL COMMENTS ...,.,.„ Kf
—> • HUMAN RESOURCES
The executive suaaary should include a description of the location and
size of the Phoenix-Goodyear Arizona Study Area. The location should be
provided in Township, Range, Section and quarter section as well as by
street address.
Response: Text will be revised from "The Unidynamics Phoenix, Inc.
Facility is located in the northern portion of the Phoenix-Goodyear
Airport (PGA) Superfund area" to "The Unidynamics Phoenix, Inc. facility
is located in the northern portion of the Phoenix-Goodyear Airport (PGA)
Superfund area located in Goodyear, Arizona.
Chapter 2 of the FS provides a detailed site description and which
locates the facility relative to the PGA study area. The text will
provide the Township, Range, Section and quarter section.
2. EXECUTIVE SUMMARY. PAGE 1
Although Waste Facility 1 nay be the principal source of groundvater
contamination, investigation results indicate that other sites have
contributed also.
Response: The TCE concentration found in these other sites are low
relative to the concentrations observed at Waste Facility 1. Therefore,
these other waste facilities are not considered to be as significant as
Waste Facility 1. These findings are expanded upon in Chapter 2, pages
2-12 to 2-18 of the RI.
The author should introduce the geologic units and the subunits before
discussing groundvater quality impacts and implications.
Response: This section is used for presenting significant results of
the Remedial Investigation; therefore, it is more appropriate to present
more detailed definitions and explanations elsewhere. In this case,
geologic information is discussed in Chapter 3, Section 3.2.1, pages 3-3
to 3-9 of the RI.
Although Subunit A contains groundvater with high TDS and TCE
contamination, it is still classified as a drinking water aquifer and is
protected for drinking vater use by the Environmental Quality Act,
Arizona Revised Statutes (A.R.S.) Title 49-224.B. (la order to
reclassify an aquifer, ALL of the following criteria must be met: the
aquifer is hydrologically isolated, vater froa the aquifer is not being
used as drinking vater, and the short and long ten benefits to the
public in degrading the aquifer significantly outweight the short and
long term costs to the public of such degradation.)
Response: Subunit A is classified as a Class III aquifer and
health-based cleanup levels are not appropriate for a Class III aquifer.
Therefore, the existing quality of Subunit A groundwater is unsuitable
as a drinking water supply and for most agricultural purposes.
Additionally, the Arizona law referred to is not considered an ARAR; see
our comments on this issue dated August 1, 1989.
-------
Response to ADEQ comments
.laced July 7, 1989
Page 2
If Subunit B possesses lover permeability, then how did Subunit C become
contaminated?
Response: The text states that Subunit B "inhibits", not stops.
vertical migration of ground water. It is still possible that
contaminated ground water may migrate from Subunit A through Subunit B
into Subunit C although at a reduced rate.
Subunit C IS a drinking water source (rather than a potential source as
stated in the text).
Response: Comment noted. Subunit C is not currently used for drinking
at the location where contaminants are detected. Therefore it is a
potential source at that location. The text will be revised from: "The
shallow ground water is separated from a potential drinking water
aquifer (Subunit C) by a zone of lower permeability geologic materials
(Subunit B)." to "The shallow groundwater is separated from drinking
water supplies (Subunit C) by a zone of lower permeability geologic
materials (Subunit B)."
City of Goodyear (COG) wells located within 500 feet of DPI's property
boundary produce groundwater for public water supply. These COG wells
draw water from the Middle Fine-grained Unit (MFD). Consequently, the
MFD is a CURRENT source of drinking water NOT a potential source.
Response: Comment noted. The text will be revised from "The Middle
Fine Grained Unit Beneath Subunit C is also a potential source of
drinking water in the area." to "The Middle Fine Grained Unit beneath
Subunit C is also a source of drinking water in the area."
3. EXECUTIVE SUMMARY. PAGE 2
The groundwater objectives should include the restoration of the aquifer
to meet ARAR's. ARAR's include not only federal water quality
standards, but also the State of Arirona environmental quality laws and
aquifer water quality standards*
Response: Comment noted. Arizona laws are not considered ARARs for
this site. See our legal comments dated August 1, 1989.
Evaluation, screening and selection of remedial action objectives and
alternatives for groundwater and soils should have been performed
separately. (The combination of soil and groundwater alternatives
weaken* the overall choices.)
Response: The separate options for groundwater and soil treatment were
evaluated and screened separately in Chapter 5 of the FS. Remedial
alternatives were presented in Chapter 6 of the FS as Alternatives A-l
for ground water treatment only and as Alternative A-2 for soil
treatment only.
-------
dated July 7, 1989
Page 3
Alternative A-4 includes pumping and creating groundvater with
concentrations above 100 ppb TCE. How was this 100 ppb target achieved?
Target clean-up areas should be defined by concentrations above
background and ARAR's.
Response: Estimates predict that reducing the TCE concentration to 100
ppb in Subunit A will protect Subunit C from TCE contamination.
Therefore, the scope of this alternative was not that of Subunit A
remediation but that of Subunit C protection. See Chapter 5, Section
5.2.14, pages 5-8 to 5-9 of the FS.
Why does the heading for Alternative A-4 include a pumping rate?
Including a puaping rate for this alternative but not the others is
inconsistent. Pumping rates for the alternatives should be determined
based on the desired time for restoring the aquifer, the number of wells
to be pumped, and the target areas.
Response: Alternatives A-0 through A-3 use no action or air stripping
(should MCLs be exceeded) treatment for withdrawal at point of use.
Alternatives A-4 pumps ground water at a rate of 400 gpm from Subunit A
using extraction wells, while the withdrawal rate of Alternatives A-0
through A-3 are dependent upon production well capacities.
The heading for Alternative A-4 mentions re-injection but the text
beneath the heading does not include re-injection. In addition, why
does Alternative A-4 specify a particular treatment method rather than
just treatment in general. Either more alternatives should be included
here and each alternative should specify methods of treatment for soil
and groundwater, or the alternatives outlined here should be generic.
Alternative A-4 suggests the use of production veils. Should the tern
"production well" be replaced with the term "extraction" wells or is the
text referring to municipal and domestic supply wells?
Response:
o Reinjection is listed in the text beneath the heading (See Executive
Summary, Page 3, Paragraph 2, Bullet 2 of the RI).
o As the text points out, the remedial alternatives that are listed in
the Executive Summary are those that survived the screening process
detailed in Chapters 4 to 6 in the FS. Since this is a summary of
the alternatives most likely to be used it would be inappropriate to
list all possible treatment methods. To retain consistency, air
stripping should also be mentioned.
o Comment noted. The text will be revised from "Removal would take
place via production wells and treatment would be accomplished with
air stripping." to "Removal would take place via extraction wells and
treatment would be accomplished with air stripping."
4. EXECUTIVE SUMMARY. PAGE 3
This document should evaluate the potential alternatives rather than
argue for a preferred or "recommended alternative.
-------
Response Co ADEQ comments
.dated July 7, 1989
Page 4
If Che auchor insists on scacing arguments for recommended alternatives,
Chen please note that Che No Action Alternative is not considered an
acceptable alternative. No Action would not satisfy state ARAR's nor
would ic be protective of human health and Che environment.
Response: The purpose of the RI/FS is to present the methodology used
in the development of the remedial investigation and feasibility study
as outlined by the Superfund program. As stipulated by EPA, the FS
presents remedial alternatives which must undergo an evaluation
methodology that satisfies certain criteria. The Executive Summary
merely summarizes the results of the screening and evaluation process
and presents a recommendation for consideration by EPA for approval,
adjustment or reinjection. This applies also to the No Action
alternative. The No Action alternative is suitable as a recommended
alternative for consideration since the response action incorporates
monitoring activities and implementation of institutional controls for
groundwater withdrawal from Subunit C and the MFU for drinking water
supply and maintaining the existing non-applicable use of Subunit A
groundwater. Institutional controls, such as mandated screening depths
within Subunit C and the MFU, would ensure continued protection of human
health and the environment and thus, may be waived from ARARs.
5. CHAPTER 1. PAGE 1-2. PARAGRAPH 2 (LAND DSE) _
This paragraph is awkward. Are you referring Co Che use of land that is
adjacent co Che site? (Suggested wording: The land adjacent Co the PGA
sice is used for residential, commercial, and agricultural purposes.)
Response: We find the meaning of this paragraph to be straightforward.
The text is stating that land uses adjacent to the UPI site are for
various purposes including residential, commercial and agricultural.
6. CHAPTER 1. PAGE 1-2. SECTION 1.2.3. PARAGRAPH 1
Inorganic contamination should be addressed in this section.
(Currently, the text only discusses VOC contamination.)
Response: The subject of inorganic contamination is addressed in
Chapter 1, page 1-3, Section 1.2.3, Paragraph 3 of the RI.
7. CHAPTER 2. GENERAL COMMENT
The units of concentrations listed in the text are inconsistent with the
units used in the tables* This practice makes coaparlson between the
text and the data very difficult. In addition, the use of different
formats and order of presentation between the various cables makes
comparison difficult*
Response: Concentration units have consistently been presented in terms
of ug/kg for organic, metal, pesticide, and Total Petroleum Hydrocarbon
chemical species. The two exceptions to this general statement occur in
Chapter 2, Page 2-21, Section 2.3.3, Paragraph 3 of the RI and in
-------
response *o n-Jiv comments
dated July 7, 1989 .......
Page 5 --.---
Chapter 2, Table 2.11 of Che RI. This was done noc Co make Che reading
more difficulc buc was done in order Co facilicate comparison of cesc
resulcs Co federal standards.
8. CHAPTER 2. PAGE 2-2. SECTION 2.2.2. PARAGRAPH 1
The second bailee of paragraph one is awkward. (Suggested wording:
Evaluate past disposal points which represent potential sources for
groundwater contamination.)
Response: Comment noted.
9. CHAPTER 2. PAGE 2-3. PARAGRAPH 2
Figure 2.2 includes a description of Che waste disposal areas.
Including Figure 2.2 as a point of reference for the waste facilities
and sampling locations would be helpful.
Response: Comment noted.
10. CHAPTER 2. PAGE 2-5. SECTION 2.2.2.3. PARAGRAPH 3
Providing a list of the compounds that were identified during the
interviews would be useful.
Response: The compounds are: calcium chromate, iron powder, titanium,
magnesium, mercury, lead oxide, barium chromate, lead chromate and
tungsten. This list is found in Chapter 2, Page 2-19, Section 2.3.3,
Paragraph 2 of Che RI.
11. CHAPTER 2. PAGE 2-5. SECTION 2.2.2.3. PARAGRAPH 4
Please provide a description of the "hot-gas" pesticide application
method. When was it used?
Response: The hoc gas dissemination process is discussed in the
"Revised July 31, 1987 Soil Sampling Plan for Unidynamics Facility". A
device was used Co disperse materials carried in hoc gases.
The process was cesCed becween Che cime periods: 1964-1970 (dyes) and
1968-1969 (pesCicides).
12. CHAPTER 2. PAGE 2-6. PARAGRAPH 2
Please explain why samples obtained from the reactive waste storage area
were only analyzed for total petroleua hydrocarbons. Were other
analytical methods used? What "reactive" wastes were stored in this
area?
-------
Response to ADEQ comments
dated July 7, 1939 - ' -
Page 6
Response:
o The "Revised July 31, 1987 Soil Sampling Plan for Unidynamics
Facility" lists three analytical suites for Waste Facility 9 in Table
6.6. These are total petroleum hydrocarbons (EPA 418.1), total
metals and EP-TOX metals.
o Various chromate, nitrate, perchlorate and oxide compounds are
assumed to compose the "reactive wastes".
13. CHAPTER 2. PAGES 2-11 TO 2-18. SECTION 2.3.2
Although concentrations of VOC's in Ehe soils vary among" the potential
disposal areas, the presence in the soils is so widespread that all the
designated waste disposal facilities are probably potential sources of
groundvater contamination. VOC concentrations detected at depth in the
soils may be more an effect of the disposal method (into dry wells) than
the result of off-gassing from the eontaainated groundwater.
Response: The remedial investigation recognized the potential of
various waste disposal areas contributing to the groundwater
contamination. However, certain indicators, such as; depth of
contamination versus depth of disposal facility; soil properties and
mechanics and; available historical accounts, substantiate the assertion
that most of these facilities, although potential contributors, are not
significant contributors and that the widespread presence of VOC
contamination is the result of off-gassing from the contaminated
grounawater. For location specific discussions, see responses to
comments 17, 18, 19, 20 and 21.
14. CHAPTER 2. PAGE 2-12
Are Ehe construction details of the dry wells known (I aa especially
interested in the depth and perforated intervals)? Are the "vaults" the
same as the concrete sediaentaiton tanks? Please describe the design
details of both (if they are different).
Response: The design details, such as depth and perforated intervals,
are not currently known for the dryvells, sedimentation tanks or vaults.
The vaults are not the same as the sedimentation tanks but refer to Che
below grade collection facilities which contain stainless-steel
55-gallon drums, located adjacent to Buildings 1 and 6.
15. CHAPTER 2. PACE 2-12. SECTION 2.3.2.1
What were the sampling intervals for Waste Facility 4 and which samples
were analyzed? (See the coaaent below in regard to Table 2.4)
Response: The analyzed samples were taken from depths of 10, 20, 30,
40, 50, 60 and 70 feet below land surface. This information is
presented in Chapter 2, Table 2.3 of the RI.
-------
daced July 7, 1989
Page 7
16. CHAPTER 2. TABLE 2.3 AND 2.4
Using Che same format for Che two tables listed above (especially in
regard Co sampling intervals and analysis of samples) and presenting the
same types of data in the two tables would make comparing the tables and
tracking the samples easier for the reader.
Response: Comment noted.
17. CHAPTER 2. PAGE 2-13. SECTION 2.3.2.1.
PARAGRAPH 2, LAST SENTENCE
Would a clear maximum in TCE concentration be expected in a
heterogeneous soil profile?
PARAGRAPH 3, LAST SENTENCE
Can the conclusion be made that Che "low" concentration of TCE found in
Che subsurface is directly related to Che amount of TCE disposed in a
dry well? Other facCors are at work and could affect the TCE
concentrations (i.e. time and Che potential for both lateral and
vertical migration away from the dry well.)
Speculation Chat TCE is "off-gassing" from Che water cable is
unsubstantiated. First, if TCE is partitioning to soil-gas and
migrating upward, Chen TCE concentrations in soil samples should reflect
Che process. Second, if in parcicioning is occurring, then one would
expect to find the highest concentrations of TCE at Che water cable and
gradually decreasing all Che way up Cowards Che surface (dissipating
upwards). Soil boring results seem to suggest varied concentrations at
different depths (no definite depth/concentration correlation) and
possibly indicate preferred cones of migration (as might be expected
from disposal in a dry well and downward migration of fluid). Third, if
off-gassing is occurring one might expect Co find similar patterns of
contaminant concentration in all Che borings. Finally, even if TCE is
partitioning and migrating from Che water Cable, it still constitutes a
zone of soil contamination that requires evaluation and consideration.
Also, dry wells usually discharge through a perforated pipe located
below a ten to fifteen foot deep seeding chamber (and Che upper portion
of Che casing is noc always perforated). Coasequently, contamination
resulting form dry wells would tend to occur below Che upper fifteen or
twenty feet of soil.
LAST PARAGRAPH
Switching units from micrograms per liter Co micrograms per cubic
centimeter causes unnecessary confusion.
Response: Chapter 2, Page 2-13, Section 2.3.2.1, Paragraph 2,
Last Sentence
The sentence hypothesizes the existence of three phases in the s.-'. :
media: soil vapor, sorbed TCE coating soil particles and aqueous pw..*s-
with dissolved TCE. Even within a heterogeneous soil profile the ac,.--
-------
Respo.nse Co ADEQ comments
dated July 7, 1989
Page 8
of contaminant per volume of soil ascribed to the solvent phase or
aqueous phase could vary.
For example, consider the case of an aqueous phase contaminated with TCE
moving downward through the soil. This phase moves through the soil due
to capillary action and/or gravity. This phase does not simply drain
through the soil because the liquid can be held by the soil pores
through surface tension. When a column of water is not heavy enough to
overcome the surface tension of the soil pore it cannot move downward
any further. This would be a "front" at some percentage of soil
saturation called the irreducible saturation. The soil near the
retained liquid would have some of the liquid sorbed onto the soil
surfaces. The amount of contaminant sorbed onto the soil would be
significantly less than the contamination at the "front." The
contamination at the front would represent a clear maximum concentration
if a profile were composed.
Paragraph 3, Last Sentence
o Comment Actually references pp. 2-13 to 2-14
o The concentration must be related to the amount of TCE disposed in a
dry well because of the principle of conservation of mass. There are
mechanisms that cause the migration of contaminants in the
subsurface. Many of these are in turn driven by amount (surface
tension, dissolving in soil water) and concentration (diffusion).
The extent to which these mechanisms play a role in migration is
dependent on amount and concentration. Greater amounts and higher
concentrations indicate greater migration potential. Therefore, it
appears that low measured concentrations are related to lesser
disposed amounts.
o Regarding the attribution of TCE observations to off-gassing:
- Generally TCE concentrations do reflect the process of
volatilization from the ground-water surface. The highest TCE
concentrations were observed at depth for borings in near Waste
Facilities 3, 5, 8, 7, 10, and Buildings 11 and 19, and the Drum
Storage Area. In these borings TCE was observed at higher
concentrations nearer the water table or were only detected near
the water table.
- The text presents that variations in TCE concentrations in Boring
04A could be attributable to variations in soil properties such as
porosity, density, and permeability (Page 2-13, para 2).
- The near uniform nature of contamination in Boring 04A could be
attributable to the soil vapor achieving equilibrium with che
contaminated ground water throughout the soil column. This
process would take an undetermined amount of time. This process
would be comparable to placing a bottle of cologne in one corner
of a closed room. Even with no air currents, the concentration ;:'
cologne would eventually be the same throughout the room.
-------
dated July 7, 1989
Page 9 -
- The PGA soils sub-committee has not yet determined appropriate
soil clean-up standards. Evaluation and consideration of soil
contamination emanating from the ground water is not currently
justified by State action levels. The concentrations are below
state action levels.
o The typical dry well design at Unidynamics' facility located the
discharge approximately 30 feet below ground surface.
o Comment noted regarding change of units in last paragraph of section.
18. CHAPTER 2. PAGES 2-15. SECTION 2.3.2.2
PARAGRAPH 1
Table 2.1 indicates that Waste Facilities 3, 5, and 8 were associated
with dry wells. Higher concentrations at depths of 60 feet probably
result from the injection through the dry wells rather than off-gassing.
Response: Chapter 2, Figure 2.2 of the RI approximates the depth of the
dry wells for Waste Facilities 3, 5 and 8 as 30 feet. The VOC
concentrations as a function of boring depth is listed in Chapter 2,
Table 2.8 of the RI. If the theory that the organic concentrations are
a result of injection through the dry wells is accurate, then it would
be expected that some organics would be detected in the 30-50 feet
boring depth range. Since Table 2.8 clearly points out that detection
of organic compounds occurs only at depths greater than 50 feet, the
assumption that higher concentrations are a result of injection through
the dry wells is probably inaccurate.
PARAGRAPH 2, LAST SENTENCE
The waste facilities discussed consist of sedimentation tanks connected
to dry wells. The occurrence of TCE at depth is probably the result of
this disposal. If no surface spills occurred, then why would shallow
contamination be expected?
Response: If TCE detection in the soil borings was a result of
contaminant disposal through dry wells rather than off-gassing from
contaminated ground water then TCE should have been discovered in
shallower depths for the same reasons as those listed above. Since this
does not seem to be the case, this assumption should be dismissed.
19. CHAPTER 2. PAGE 2-16. SECTION 2.3.2.3.
Low levels "indicate" that this facility is not a source of groundwater
contamination? The low levels may "suggest" that the facility is not a
source but they do not indicate so. The text does not substantiate the
conclusion.
Response: Soil borings from Waste Facility 7 were submitted for VOC
analysis for depths of 10, 20, 30, 40, 50, and 60 feet below land
surface (see Chapter 2, Table 2.4 of the RI). The results are presented
in Chapter 2, Table ^.8 of the RI and indicated that only 1,1,1-TCA is
present and only at a depth of 10.0-11.5 feet below land surface. No
-------
Response to ADEQ comments
dated July 7, 1989
Page 10
other organic compound is found at any other analyzed depth. If this
facility were to be a ground water contaminant source, than a 1,1,1-TCA
concentration gradient would be present throughout the soil boring.
Since this is not the case, the conclusion is correct that the data in
the text indicates that Waste Facility 1 is not a source of ground water
contamination.
20. CHAPTER 2. PAGE 2-16 AND 2-L7. SECTION 2.3.2.4
If TCE or TCA were detected in every interval from 10 to 50 feet, than
this facility represents a potential source of groundwater
contamination. -
Response: The text reads: "This facility is probably not a significant
source of VOCs in ground water". This statement does not eliminate this
facility from being considered as a potential source of ground water
contamination. It asserts that this facility is not a significant
source of ground water contamination.
21. CHAPTER 2. PACE 2-17. SECTION 2.3.2.6. PARAGRAPH 2
SENTENCE 2
Define "low" as used in this sentence. Use of an actual concentration
range would add clarity to the text. Presumably, concentrations were
above detection levels, but were they below 500 ppb?
Response: Laboratory results for soil borings 19A-C are listed in
Chapter 2, Table 2.8 of the RI. TCE concentrations range from 147-1480
ppb at soil depths of 20-40 feet below land surface. The highest
detected concentration of TCE is relatively low when compared to the
concentrations detected in Waste Facilities 1 and 4.
Higher concentrations of TCE at depth may also be a manifestation of
disposal through a dry well.
Response: As stated in the text, Building 19 is located near Waste
Facility 1. Waste Facility 1 is comprised of 4 dry wells (see Chapter
2, Figure 2.2 of the RI). The disposal of solvents into these dry wells
has resulted in ground water contamination at TCE levels exceeding
100,000 ug/kg which in turn has led to the discovery of TCE in Borirg
19A-C due to off-gassing of contaminants from the groundwater.
Therefore, to state that higher concentrations of TCE at depth may also
be a manifestation of disposal through a dry well is unnecessary and
redundant since this has already been shown to be true.
22. CHAPTER 2, PAGE 2-18. SECTION 2.3.2.7
Attempting to guess the concentration of the source seems pointless
since the volumes of material disposed are not even known. In addition,
the suggestion that rainwater filtering through empty drums constituted
the original source is unsubstantiated and represents pure speculation.
-------
dated July 7, 1989
Page 11
Response: Concentration values were not "guessed" at, they were
scientifically determined using EPA Method 8010/8020 at an approved
laboratory. Second, it is not necessary to know the original volume of
disposed material in order to determine concentration within the soil.
23. CHAPTER 2. PAGE 2-18. SECTION 2.3.2.8
If contamination is present, then its a potential source. What was the
range of concentration detected?
Response :
o The text does not dismiss the solvent collection area as a potential
contamination area. It states that these areas are not significant
ground water contamination sources.
o Chapter 2, Table 2.8 of the RI lists concentration ranges for the
following chemicals (note: no distinction is made between boring or
boring depth):
Compound Concentration Range (PPB)
TCE 89-4260
1,1,1-TCA 12-10800
Ethyl Benzene 563
Xylene 743-4600
24. CHAPTER 2. PAGE 2-19 to 2-21. SECTION 2.3.3
The presence of high concentrations of metals in selected soil samples
may not be anomalous or be disregarded. Instead, they nay be indicative
of a problem in a fairly limited area.
Response: The text does not disregard results from soil samples as
being anomalous. The discussion concerning barium and aluminum
concentration results (Chapter 2, Page 2-20, Section 2.3.3, Paragraphs 2
and 3) states clearly that the samples from a tank (for barium) and
from within a pond (for aluminum) were not representative of soil
concentrations. Only these were considered anomalous and disregarded.
It was never implied that a problem could not exist within a limited
area.
25. CHAPTER 2. PAGE 2-20. PARAGRAPH 3
It's a little too convenient to say, "...the consistent occurrence of
arsenic in soils at DPI facility above background determined for the
airport at the southern part of the study area probably indicates that
background concentrations at Unidynanlcs facility aay be generally
higher than for the airport." Unidynamics is locate less than one mile
from the airport. It seems unlikely that two sites located less than
one mile apart possess different ambient soil values for arsenic. This
sentence is misleading.
-------
Response Co m,c,,< v.uuunent.3
dated July 7, 1939 . • . • .
Page P.
Response: There are several circumstance which support the text's
contention that arsenic background concentrations may differ for soils
at the UPI and PGA sites.
1) A review of manufacturing processes and interview results indicated
that arsenic was never used at this site. For this reason, arsenic
should not have been detected unless it was a component of the
ambient soil.
2) Soil sampling was performed at Waste Facilities 2, 2, 5, 6, 8, 9, 10,
and 11. The results are listed in Chapter 2, Table 2.9 of the RI..
The mean concentration of arsenic was calculated to be 21.6 ppm with
a standard deviation of 7.6 ppm. There did not seem to be any
relationship between soil depth and arsenic concentration. This
analysis showed that the arsenic concentration within and throughout
the soil remained fairly constant giving credence to the theory that
ambient soil conditions (at least for arsenic) for UPI and PGA may
indeed be different.
2) The assumption that arsenic concentration soil levels at UPI are the
result of arsenic disposal is not supportable. If this assumption
were to be true then it would be expected that an unusually high
level of arsenic would be found at one or two locations (as was the
practice of TCE disposal). Instead, the evidence points to a low,
constant level of arsenic throughout the site. This would lead away
from the idea of the higher UPI background results being a
consequence of UPI disposal and toward the idea that there is a
naturally occurring level of arsenic that is higher at the UPI site.
26. CHAPTER 2. PAGE 2-21. PARAGRAPH 2
Were samples obtained Just from within the tank or were they obtained
from around and below the taak? It is not clear in the text. With such
high values, vac Che possibility of tank leakage addressed in the
sampling?
Response: As seated in the text, Stage II samples exhibiting the
highest concentration of the various metals were selected for EP
toxicity analysis of priority pollutant metals. These samples are
listed in Chapter 2, Table 2.11 of the RI. The location feature that is
sampled is identified from the sample designation using Chapter 2, Table
2.2 of the RI.
Sample Designation Feature Sampled
Sample B Building 11 - Borings at Front of
Sample C Building
8A Waste Facility 8 - Boring at Dry Well
10A Waste Facility 10 - Boring at tank
7A Waste Facility 7- 2 Borings in Leach
7B Field
-------
Response to ADEQ comments
dated July 7, 1989 -
Page 13 -
The Phase III Sampling Plan is summarized in Chapter 2, Table 2.4 of the
RI. This table reveals that samples were analyzed for boring depths
that were below the level surface. (Stage I Samples, as described in
Chapter 2, Page 2-4, Section 2.2.2.2. of the RI, are those from inside
the tank).
From all of this information, the question should be addressing Sample
IDA only. Again, referring to Chapter 2, Table 2.11 of the RI the EP
Toxicity Test Results for this sample for each metal of interest are
listed below (unit are ug/1):
7 Arsenic < 0.5 Lead < 0.1
Barium < 1 Mercury < 0.01
Cadmium < 0.1 Selenium < 0.5
Chromium < 0.1 Silver < 0.1
Interpretation of this data reveals that the highest detected metal,
barium, has a concentration that is less than one percent of the Federal
EP Toxicity standard of 100 mg/1. Groundwater quality date coupled with
the EP Toxicity data indicates that the soil at this particular location
has a low metal concentration and does not serve as a source of metals
to ground water. Therefore, the possibility of tank leakage need not be
addressed in this sampling.
27. CHAPTER 2. PAGE 2-21. PARAGRAPH 3
What about the concentration of metals in relation to ADHS health-based
soil clean-up levels? Although not promulgate, the clean-up levels
still constitute a "to be considered" (TBC).
Response: In our previous comments we demonstrated why assumptions
behind the ADHS numbers are not similar to circumstances at the site;
hence, as TBCs, the are not useful.
o The ADHS - suggested health-based clean up levels for metal
contaminants are listed in Chapter 2, Page 2-37, Table 2, Vol. I
(Public Comments Draft) of the RI/FS. Seven metals within the UPI
site have been found to have soil concentrations that exceed average
background levels analyzed in soil samples at the PGA site: arsenic,
barium, aluminum, mercury, lead, chromium and zinc (see Chapter 2,
Page 2-19 of the RI).
o There do not appear to be any ARARs that are directly related to
metal contaminants in soils at the UPI site. And, as was. pointed
out, ADHS health based soil clean up levels may be (but are not now)
adopted at some time in the future in the State of Arizona.
28. CHAPTER 2. PAGE 2-21. SECTION 2.3.4
Background concentrations of dieldrin and chlordane would need to be
determined before these concentrations are attributed to agricultural
use only.
Response: Comment noted.
-------
Response co ADEQ comments
dated July -7, 1989
Page 14
29. CHAPTER E. PAGE 2.22. SECTION 2.4
1st billet- This is only true for 4,4'-DDE.
Response: Comment noted.
4th billet- Table 2.1 lists a number of locations where disposal of
solvents occurred into dry wells. Therefore, unless these solvents did
not include TCE, distinct evidence does exist that TCE disposal to soils
occurred at these other locations.
Response: Since no records were kept of the solvent waste disposal
system at UPI, it is impossible to speak with absolute confidence as to
which location a particular solvent was discarded. Therefore,
inferences must be made based upon soil boring analysis. The Waste
Facilities which could have conceivably received waste TCE are numbers
1, 2, 3, 4, 5, 6, 7, 8, 10 and 12, Buildings 11 and 19, Drum Storage
Areas A and B, and Solvent Collection Areas A, B, C and .0. No TCE was
detected in Waste Facilities 2, 7 or 8, nor in Building 11 (Chapter 2,
Table 2.8 of the RI) so these can be eliminated. Waste Facilities 3, 5,
and 6 contain TCE concentrations only at depths below 60 feet and in
quantities that are most likely the result of off-gassing from
contaminated ground water and not migration from a dry well (Chapter 2,
Pages 2-15 to 2-16, Section 2.3.2.2 of the RI). The TCE concentrations
found at the remaining sites, Waste Facilities 4, 10 and 12, and the
Drum Storage and Solvent Collection Areas, may or may not be a result
of disposal to the soil. However, the concentrations are low (compared
to Waste Facility 1) so that no definitive judgment can be made.
Therefore, unless distinct evidence (i.e. written records, verbal
confirmation, etc.) can be found, then the statement in the RI stands.
last billet- The presence of 1,1,1-TCA in groundwater beneath the
facility indicates that its presence in the soil vas significant enough
to impact groundvater.
Response: The text reads: "concentrations of TCA in soil are not a
significant source to groundwater". TCA concentrations in the soil (or
in Subunit A groundwater) are insignificant when compared to TCE
concentrations. Since the methods used in treating TCE are also
successful in treating TCA, the relatively small concentrations of TCA
will not need to be considered in the design of the treatmer.,. process.
This is the justification for the comment in the RI.
30. CHAPTER 3. PAGE 3-1. SECTION 3.1.1. PARAGRAPH 1
Please provide well completion data for monitoring wells 1-4.
Response: The available well completion data for monitoring wells 1-4
is found in Chapter 3, Page 3-19, Table 3-10, Vol. I (Public Comments
Draft) of the RI/FS.
-------
<^esponse .o n_.:.v< comments
daced July 7, 1989
Page 15
31. CHAPTER 3. PAGE 3-3. (LAST BILLET)
The Phase II report stated that a Cement Bond Log was run on MV-14, but
the log Is .not included here. Was the log run but just excluded? Or is
the statement incorrect?
Response: The log was run but was excluded.
32. CHAPTER 3. PAGE 3-3. LAST PARAGRAPH
If well 33dcd is an integral part of the monitoring network, then why
isn't water quality data for this well included in Appendix D? Although
it . is stated that 22 wells were sampled during the remedial
investigations, no data is included for any wells other than the DPI
monitor wells.
Response: Well 33dcd was sampled and monitored by EPA. Likewise, the
other wells (not included by UPI) are included under EPA's reports.
33. CHAPTER 3. PAGE 3-8. LAST PARAGRAPH
This site is underlain by several thousand feet of alluvial sediments.
Response: Comment noted.
34. CHAPTER 3. PAGE 3-10. LAST PARAGRAPH
Subunit B does not hydraulically separate Subunits A and C.
Response: Subunit B is comprised mainly of finer-grained material.
Because of this finer-grained material, Subunit B has a lower
permeability and hydraulic conductivity than that of either Subunit A or
Subunit C. Vertical and horizontal velocity gradients from Subunit A to
Subunit C are impeded because of Subunit B. This condition defines a
hydraulic gradient.
35. CHAPTER 3. PAGE 3-15. LAST PARAGRAPH
TDS concentrations in on-site Subunit A monitor wells are significantly
higher than in off-site veils. Water quality types are different
on-site and off-site. Therefore, it is likely that the facility
activities have had significant impacts on inorganic water quality in
addition to the historic agricultural activity in this area.
Response: The observed variations in TDS concentrations and water
quality types may have origins other than facility activities. The
wells are widely spaced and the observed variation may be a result of
natural variability. Off-site wells are generally deeper than on-site
wells and the variability may be related to this difference in depth.
MW-1, an upgradient well on site contains the same general TDS and water
quality type as monitor wells on the facility. This indicates tha:
"facility activities" are not responsible for the variability observed.
-------
Response to ADEQ comments
dated July 7, 1989
Page 16
In addition, interviews and a review of operations did not reveal any
processes that would have a "significant impact on IDS or water quality
types.
36. CHAPTER 3. PAGE 3-18. PARAGRAPH 3
No data is presented to support changing TCE concentrations with time.
A series of figures with actual TCE concentrations over time would be
more useful than the aean concentration values presented in Figure 3.13.
Response: Comment noted.
37. CHAPTER 3. PAGE 3-18, PARAGRAPH 3 (Subunit A)
Is there a possible explanation for the rise in the TCE concentration
for monitoring well MW-12?
Response: Yes, MW-12 is in the plume, downgradient of the source,
screened only in Subunit A.
38. CHAPTER 3, PAGE 3-19
PARAGRAPH 1
What is the source of TCE concentrations in well SC4A if not necessarily
attributable to TCE in Subunit A? Does this mean that Subunit C is
contaminated at thia location?
PARAGRAPH 2
By not providing waste quality analysis over time, it is difficult to
substantiate the statement that TCE concentrations in MW-6 do not
indicate a rising trend in concentrations. A TCE concentration of 6
eicrograms per liter at MW-6 exceeds MCL's for TCE.
Response:
o Subunit C is not likely to be contaminated at this location, this is
a typo and Subunit A in the last sentence should be Subunit C.
o The text states that the agricultural production well SF4A is
screened in Doth subunits A and C.
o Within the well SF4A, water from subunits A and C would be mixed.
Subunit A water would be diluted with subunit C water.
Paragraph 2
o Measured values fluctuating between 2.0 and 6.0 mg/1 are interpreted
to represent the inherent variability in sampling, handling and
analyses accuracy since no apparent trend is discernable.
-------
dated July 7, 1989
Page 17
42. CHAPTER 3. PAGE 3-19. LAST PARAGRAPH
The rationale here seema to be that since Che veil only serves a
warehouse, its not important. First, it supplies a warehouse which
employs approximately 280 employees. Second, the water pumped from COO
#10 provides the business with water that is utilized in food
processing. Third, the exclusivity of the aquifer is inconsequential to
the regulatory need for protection. All aquifers in the state (unless
otherwise reclassified) are protected by statute for drinking water use.
(Also, the density of TCE could affect its movement into the B/C
aquifer.)
Response:
o The heading of the comment should be Chapter 3, Page 3-20,
Paragraph 1.
o No judgment of the well and importance is implied or intended. The
well is not used in food processing. Food warehousing nearby does
not require the use of water for storage.
o The Arizona law (referred to) is not considere'd'"an~ARAR,~'see our
legal comments dated August 1, 1989.
43. CHAPTER 3. PAGE 3-20. SECTION 3.2.4
Although drinking water is available from the aquifers deeper than those
already affected by VOCs, it is not reasonable to require the drilling
of deeper wells to acquire this water. Additionally, no data is
available to determine if the MFD and/or LCD beneath the DPI site have
been affected by VOC contamination.
The implication in this section is that drinking water supply wells are
not located in an area that could be impacted by the VOC contamination
from Onidynamics. However, there are City of Goodyear wells located
within 500 feet of DPI's property boundary. These wells consistently
detect TCE contamination.
Response: While it is true that no VOC contamination data is
available for the MFU and/or the LCU underlying the Unidynamics site,
this does not preclude investigation of (its) possible use. This is
especially true when the fact that TCE is not detected in the MFU a:
other locations.
There is one well (COG 02) located within 500 feet of the Unidynamics
site. Groundwater data from this well is found in Chapter 3, Table 3-*
of the RI/FS (Public Comments Draft). According to this table, the
average TCE concentration for this well and City of Goodyear wells 1, 3,
and 6 is less than 1.5 ppb, well below the 5 ppb MCL. The location of
COG #2 is not within the known boundary conditions of the Unidynamics'
groundwater gradient. It can reasonably be concluded that Unidynami.-s
has not contaminated this particular well. Therefore, to assert cu.at
-------
Response to ADEQ comments .,
dated July 7, 1989
Page 18
VOC contamination from Unidynamics has an impact on drinking water just
because a well is located within 500 feet of the facility boundary is
not borne out by the detection results.
44. CHAPTER 3. PAGE 3-21. FIRST PARAGRAPH
The presence of 70C contamination in Subunit C indicates that Subunit B
does not act as a hydraulic barrier between Subunits A and C.
Response: Comment noted. In the text, "hydraulic barrier" was replaced
with "to inhibit movement of groundwater". This revision appears in the
5/4/89 version; the most recent document.
45. CHAPTER 3. PAGE 3-22. SECTION 3.3.2. FIRST SENTENCE
This sentence implies that the Subunit A aquifer is not considered a
drinking water source. Either change the sentence or qualify the
paragraph by stating that state lav designates all aquifers for drinking
vater use.
Response: See response to Comment 2. -
46. CHAPTER 3. PAGE 3-22. FIRST PARAGRAPH
The higher TDS concentrations in Subunit A on-site as compared to
off-site indicate influences in addition to the historic deep
percolation of irrigation return flow.
Response: Comment noted. See response to Comment 35.
47. CHAPTER 3. PAGE 3-22. SECTION 3.3.2
SDBUNIT C
First, meaning of the work "poor" is unclear as used in this sentence.
Either define the word or restate the sentence. Second, whether the
aquifer is suitable for drinking water is irrelevant to the need for
remediation.
Response: Comment noted. The text goes on to state chat TDS exceed the
recommended secondary drinking water standards and that nictates
approach the drinking water limit. Therefore, it is appropriate to
state that the quality of Subunit C, although suitable for drinking
water supply, is still poor.
LAST PARAGRAPH
Concentration may suggest that Subunit B impedes downward movement of
contaminants, but they do not necessarily indicate so. (Otherwise
Subunit C would not be contaminated)
-------
Response to ADEQ commencs
dated July 7, 1989 - • .
Page 19
Response: Although Subunit B may be an impediment to contaminant
migration, it is still possible for contaminants chat were originally in
Subunit A to be found in Subunit C. An impediment is a hindrance to
migration, not a complete barrier. See response to Comment 2 also.
Wells which are screened in both Subunits A and C provide a gravity
conduit by which Subunit C can be contaminated from Subunit A.
48. CHAPTER 3. TABLE 3.1
This table is Illegible.
Response: Comment noted.
49. CHAPTER 4. PAGE 4-1. PARAGRAPH 3
TCE is still present in soils not associated with Waste Facility 1.
These other soils are probably continuing sources also.
Response:
o The text does not deny the presence of TCE in soils not associated
with Waste Facility 1.
o The text does not deny that some of the other soils areas may be
continuing sources also (in fact, this may or may not be the case).
However, to claim that all other soils are probably continuing
sources is too extreme. Technical analysis using the results of soil
borings for Waste Facility 3, 5 and 6 (Chapter 2, Pages 2-16 to 2-17,
Section 2.3.2.2 of the RI) asserts that soil contamination is the
result of off-gassing from ground water contamination (see response
to Comment 18). In addition, Building 11 (Chapter 2, Page 2-17,
Section 2.3.2.5 of the RI) and Building 19 (Chapter 2, Pages 2-17 to
2-18, Section 2.3.2.6 of the RI) do not appear to be contributing to
ground water contamination based on collected data.
50. CHAPTER 4. PAGE 4-1. LAST PARAGRAPH
Strike the first sentence and replace the word "impedes" with "hinders"
or "slows" in the next to last sentence.
Response: Chapter 2, Table 2.1 of the FS is a summary of the organic
compounds detected in Subunit C. From this table, the range of TCE
concentrations found in Subunit C is 0.7-5.5 PPB. This substantiates
the statement that TCE is generally confined to Subunit A, and that
the term "impedes" is synonymous with the term "hinders" or "slows".
Therefore, it is unnecessary to revise the text.
51. CHAPTER 4. PAGE 4-2. FIRST PARAGRAPH
The Environmental Quality Act protects all aquifers as drinking water
sources.
Response: See Response to Comment 2.
-------
CRANE
UNIDYNAMICS/PHOENIX
UNIDYNAMICS/PHOENIX
POST OFFICE BOX 46100
TELE°HONE - ISOZi
TELEX -»«74»t
TWX - 910-959-0883
FAX -
l>i-r\ 2"
PHOENIX. ARIZONA 85063-6100
2 August 1989
Mr. Jeff Rosenbloom, Chief
Enforcement Programs Section
United States Environmental Protection Agency
Region IX
215 Fremont Street
San Francisco, California 94105
RE: Response to CH2M Hill comments - Unidynamics RI/FS Report
Dear Jeff:
Enclosed per your request are Unidynamics' responses to CH2M Hill's
comments on our RI/FS.
If you have any questions, please contact me at 602/932-8245.
Very truly yours,
fu
W. C. Donahue
Director
Human Resources
WCD/dl
Enclosures
xc: M. Corash
F. Stephenson
G. Seifert
T. Ungerland
1000 NORTH LITCHFIELD ROAD
GOODYEAR. ARIZONA 85338-1295
-------
Responses to CH2M Hill R E C _ !
comments dated 7/6/89 ---
Page 1 . AUG 2 i95
' RESPONSE TO CH2M HILL COMMENTS H(JMAN RKOU WB
1. Groundwater Alternative CW-A.1: The maximum predicted drawdown under
this remedial action alternative is 88 feet. The thickness of Subunit A
used in the simulation was 90 feet. In an unconfined aquifer, the
maximum "safe" drawdown for an extraction well field is 50 percent of
the aquifer saturated thickness. This is to account for possible
aquifer heterogeneity or subsequent water level fluctuations. Clearly,
the withdrawal of 1,000 gpm from this aquifer would cause extensive
dewatering. If the pumped water were reinjected after treatment, the
drawdown would be reduced, but that process is not taken into account in
this alternative. An analysis of the capture zone estimate was not made
since this alternative cannot be successfully implemented.
Response: We agree that substantial drawdown of the water table would
occur under this pumping scenario and that it may exceed the practical
limits of the Subunit A aquifer. This extremely aggressive pumping
scenario was included in our analysis in order to provide a range of
options for EPA to evaluate as requested. We are pleased that EPA's
technical consultant recognizes the limitations of such an aggressive
pumping scenario and agree with their conclusion that further
consideration of this pumping scenario is not warranted.
2. Groundwater Alternative GW-A.2: The maximum predicted drawdown under
this alternative is 126 feet. As stated above, Subunit A has a
saturated thickness of only about 90 feet. Therefore, this alternative
will also cause extensive dewatering of Subunit A. No evaluation of the
capture zone estimate was attempted for the reasons stated above.
Response: See response to comment //I.
3. Groundwater Alternative GW-A.3: The maximum predicted drawdown under
this alternative is about 1.5 feet. Using the well location recommended
by Dames & Moore, this pumping scheme will capture only about 15 to 20
percent of the target area we estimate to be contaminated above ARAR
levels. If a more suitable well location were chosen, approximately 850
feet to the north of the recommended location, 50 to 60 percent of the
target area contaminated above ARAR levels could be captured.
Response: The "target area" estimated to be contaminated above
specified levels by EPA's contractor is subject to a wide variation in
extent since TCE above 5.0 ppb has only been detected very infrequently
in Subunit C in a well cluster at a single location. One well in the
cluster is only partially completed in Subunit C. An almost infinite
number of "target areas", as assigned by the EPA contractor in this
comment, can be drawn around a single point. However, all such "target
areas" may be meaningless since it has not been conclusively shown that
Subunit C exceeds ARARs in the vicinity of the plant site where EPA
requested that cleanup alternatives be evaluated.
Dames & Moore selected a different "target area" than the EPA contractor
upon which to base its evaluation. This analysis was performed solely
at the request of EPA. Given the lack of conclusive data, and che
-------
Responses co CH2M Hill
comments dat«;d 7/6/89
Page 2
problems posed by increased drawdown in che area of high Subunic A
contamination (as discussed in Unidynamics'.letter of July 17, 1989) the
proposed cleanup is appropriate.
4. Groundwater Alternative GW-A.4; The maximum predicted drawdown under
this alternative is about 2 feet. Using the well location recommended
by Dames & Moore, this pumping scenario will capture only a few percent
of the target area we define as being contaminated above background
levels. Even with an optimal well location, this alternative will only
capture 5 to 8 percent of the target area above background levels.
Additional wells pumping at higher rates will be necessary to capture
the areal extent of groundwater contaminated above background levels.
Response: Please see our response to comment #3 above for a discussion
on the problems of technical justification for establishing a "target
area" as the EPA contractor has done in framing this comment. There is
no conclusive evidence at this time that a representative sample of
Subunit C ground water exceeds 5.0 ppb for ICE.
Unidynamics has discussed in previous comments to the EPA (letter dated
July 17, 1989) the potential problems with increasing pumping rates in
Subunit C and the increased drawdown associated with the pumping. A
careful analysis of the relative position of the hydraulic head in
Subunits A and C under any potential cleanup scenario must be completed
prior to establishing design criteria for the groundwater extraction
system. Failure to consider the potential adverse water quality
degradation that may result from the downward migration of contaminants
from Subunit A into C as a result of proposed remediation in Subunit C
could lead to a remedial action that causes more of a problem than it
solves.
5. The equipment sizing and costs for the groundwater alternatives were not
reviewed since by UPI's admission the sizing basis is wrong.
Response: Comment not understood. Order of magnitude costs based on
preliminary design have been provided*
Preface to comments 6 and 7:
Several statements have been made which infer that Unidynamics have
failed to "...address the entire range of contaminants at the site...,
not just TCE." Please refer to Table 3.6 of the May 4, 1989 RI, where
eleven VOCs other than TCE are listed as being detected in monitor
wells. The range of concentrations found (in ppb) is also listed in
this table.
In CH2M Hill's comments dated March 23, 1989, comment No. 4 ..."The
results for acetone and other organic compounds are not of as much
interest because they are not major components of measured ground water
contamination at UPI. The exception is MEK which was found at high
concentrations at UMW-4". Thus, the level of concern seen in these most
recent CH2M Hill comments seems unwarranted.
-------
Responses to CH2.M Hill
comments dated 7/6/89 -
Page 3
Furthermore, of the eleven VOCs detected in groundwater in Subunit A,
other than TCE, the only VOC detected in any appreciable concentration
is Methyl Ethyl Ketone (MEK). MEK is also the only "contaminant" found
that is not easily treated, especially by air stripping. Air stripping
for removal of TCE will, to a sufficient extent, remove the other
"contaminants" as well. Studies performed with "mixtures" of VOCs
present in the "ppm" range in feedwater to air strippers showed no
effect on the mass transfer of each caused by the mutual presence of the
others.
However, due to the presence of MEK, and the potential for traces of
other VOCs, remedies beyond air stripping were examined.
6. The supplements do encompass some additional alternatives for
remediation of the site, but they fail co address some of the other
shortcomings of the main text. In some cases they contradict the main
text. They also suffer from the fact that in many cases they still do
not address the entire range of contaminants at the site.
Response: In CH2M Hill's comments dated March 23, 1989, comment No. 4
..."The results for acetone and other organic compounds are not of as
much interest because they are not major components of measured ground
water contamination at UPI. The exception is MEK which was found at
high concentrations at UMW-4." (See response to comment No. 5)
7. UPI has assumed that an air stripper with a GAG polishing bed is
required. The reasoning for this is not at all clear. The southern
portion of the site does not require GAG polishing to meet ARARs or
background levels. There are contaminants at the DPI site not found in
the south area, but UPI has chosen to disregard any mention of these
contaminants with the exception of MEK which they state will not be
treated. The treatment train described will remove VOCs if designed
properly (and will apparently reduce MEK levels to some degree), but an
analysis should be undertaken addressing all the contaminants at the
site, not just TCE.
Response: In CH2M Hill's comments dated March 23, 1989, comment No. 4
..."The results for acetone and other organic compounds are not of as
much interest because they are not majcr components of measured ground
water contamination at UPI. The exception is MEK which was found at
high concentrations at UMW-4." (See response to comments No. 5 and 6)
It was because an analysis was performed which did address all the
contaminants at the site, not just TCE, which lead to the need for GAC
polishing following the air stripper. It is not practical to assume
identical parameters between the northern and southern portions of the
site.
8. The text describes the air stripper as a "three-stage system." the
meaning of this is not clear. The text also fails to address the effect
that high TDS levels may have on the operation of the air stripper and
the polishing bed. The text includes no explanation of the fact that
TCE levels used for design purposes are above the solubility limit nor
of the effect this will have on the treatment train. If free product is
present, then separation may be appropriate prior to the air stripper.
-------
Responses Co CH2.M Hill
comments dated 7/6/89
Page <*
Lastly, the text states that the vapor phase carbon is regenerated
offsite. If the investment in regeneration facilities is to be made,
then why not regenerate all the carbon onsite?
Response:
o "Three stage system" should be interpreted as an air stripper system
comprised of three air strippers in series. The text will be amended
to this wording to avoid confusion.
o Please also refer to our response to the 3/23/89 CH2M Hill comments;
comment number 23.
o A compound can be removed from the liquid feed to an air stripping
unit only if it can move with the vapor phase under the operating
condition with in the stripping unit. TDS are not capable of doing
this and so the TDS concentration in the contaminated liquid phase
will remain unchanged throughout the air stripping unit.
o For carbon adsorption to be most successful, the target molecule
should be relatively small and insoluble in water. TDS are large
relative to the carbon pore spaces in which carbon adsorption occurs
and, by definition, they are soluble in water. Neither listed
criteria for successful carbon adsorption is met and, as with air
stripping, TDS concentrations are unaffected.
o We agree with CH2M Hill's concern as regards the potentially adverse
effect that high TDS levels may have on the operation of the air
stripper and polishing bed. The Langelier Stability Index (LSI) for
Subunit A is positive indicating the potential for scaling is very
real. Further calculations indicate that the use of a scale
inhibitor such as sodium hexametaphosphate, or Flocon 100, does not
reduce the potential for scaling appreciably.
o A cost for water pretreatment was included in the O&M cost estimates.
o The solubility of TCE in water is 1,100,000 ppb or 1,100 ppm (The
Hazardous Waste Consultant, November/December 1986). The units used
in the text to express TCE concentration levels are ppb. The design
concentrations are:
- GW-A.1: 14,100 ppb TCE maximum
- GW-A.2: 34,000 ppb TCE maximum
- GW=Ae3: 14 ppb TCE maximum
- GW-A.4: 5 ppb TCE maximum
It is apparent from the above that the design maximum concentrations
are three percent or less of the solubility limit. It is likely that
the text reader/comment writer misread the concentration units in the
text.
-------
/
Responses co CH2M Hill ' -
comments daced 7/6/89
Page 5
In conclusion, the TCE design concentrations are well below the
solubility limits, thus explaining why free product separation of the
groundwater treatment plant influent was not discussed. Free product
separation would, in any case, be difficult to achieve at the pumping
rates used in this scenario, or EPA's preferred remedy.
o The text states that the vapor phase carbon system will be equipped
with a steam regeneration system to be operated on-site.
o The regeneration system operation is described in the following:
Periodically the vapor phase carbon will be regenerated with steam.
The steam will be introduced into the carbon bed and carry away
adsorbed solvents from the carbon.
Once outside the vapor phase carbon bed, cool water is passed over
the steam piping. This condenses the steam and solvents into a
liquid phase called condensate. A special condensate collection tank
holds the condensate.
If the concentration of solvents in the condensate collection tank is
greater than the solubility limit, the solvents will coalesce in a
liquid organic phase product. Special baffles in the condensate
collection tank allow the liquid organic phase and the aqueous phases
to be removed from the tank independently. The liquid organic phase
will be removed periodically and transported off-site for
incineration.
Vapor phase carbon regeneration and waste streams in summary:
Vapor phase carbon - Regenerated on-site
Condensed steam - Process through air stripper
Condensed liquid organic phase - Incinerated off-site
o Liquid phase GAC system carbon cannot be regenerated by the
regeneration system installed for the vapor phase carbon system.
Liquid phase GAC carbon must be incinerated and properly processed to
reactivate the carbon granules. There is only one U.S. facility
permitted to incinerated and reactivate spent liquid phase GAC system
carbon* The facility is off-site in Pittsburgh, Pennsylvania and
liquid phase GAC carbon would be transported to the facility.
9. The soil* analysis also leaves some unanswered questions. It fails to
address the relative effectiveness of SVE on the full range of
contaminants at the site. In contrast to the main text which
prominently mentioned the placement of a cap as an enhancement for the
SVE system, the need for the cap has been deleted here with no
explanation.
Response:
In the comments on the March, 1989 RI/FS as provided by CH2M Hil
specifically comment number 26 on th? FS, the statement was made :*
"The pilot test also indicated that a cap may not be necessar.
-------
Responses to CH2M. Hill.
comments dated 7/6/89
Page
This comment by CH2M Hill was noted and used to prepare che June,
1989 supplement.
The relative effectiveness of SVE for removal of a contaminanc is
dependent on the relative soil volatility. The concept of relative
soil volatility is explained and the relative dry soil and wet soil
volatilities for the range of volatile soil contaminants at che sice
is presented below:
Soil volatility is dependent upon two phenomena: che compound's
vapor pressure and the density of its vapor relative to air (its
buoyancy). The soil volatility property does not incorporate che
compound's Henry's Law Constant. Assumptions as to treacability by
SVE are dependent on relative soil volatility and are completely
removed from assumptions as to treatability by 'air stripping.
Prejudices developed about certain compounds because of their
inability to be removed by air stripping must be avoided when
analyzing the effectiveness of soil vapor extraction.
A compound's relative soil volatility is proportional to its vapor
pressure and inversely proportional to a root of its molecular weight
(The Hazardous Waste Consultant, November/December, 1986). The
relative soil volatilities for all VOCs detected during Stage I and
Phase II soils testing except ethylbenzene are listed below.
Relative Volatility
Dry Soil Wet Soil
1,1,1-Trichloroethane 33.9 10.1
Trichloroethylene 21.5 6.3
Xylene(s) 0.99-2.05 0.27-0.31
Acetone 72.5 26.3
Methyl Ethyl Ketone 30.5 10.6
(Hazardous Waste Consultant)
It is apparent that all compounds are treatable with SVE where the
soil volatility property is used to remove the contaminant from che
soil. Although the values for xylene appear low they are still in
the moderate range of effectiveness.
o The operation of an SVE system is expected to dry the soil within che
radius of influence, particularly in a desert climate. The operation
of the system will induce the affected area to exhibit the greater
dry soil volatilities.
Some theorists would entertain that the contaminant would be air
stripped from a water phase on the surface of the soil particles.
This would have the effect of limiting the rate of removal for some
compounds. The drying action of the SVE system operation would
remove this phase.
o The decision as to whether to place a cap over the Target Areas .-s
considered a design detail to be addressed during final design .:
this alternative is implemented.
-------
Responses to CH2M Hill
comments daced 7/6/89 -;
Page 7
10. The location of the soil contamination seems optimistic in light of the
sparse soil data collected to rely on one well at each source area as
sufficient for remedial purposes. While it is true that the radius of
influence was extended to distances of 150 feet during the pilot test,
the effectiveness of the well at those distances is much reduced due to
dissipation of the air flow at that distance. Vith this combination of
sparse soil data and unpredictable SVE performance, it would be prudent
to install additional wells and overlap their radius of influence rather
than assume that one well will be sufficient. The analysis also seems
to have ignored the need for some method of evaluating the SVE radius of
influence and the need for evaluation of soil concentrations following
installation and operation of the system. Installation of soil gas
monitoring wells would be appropriate.
Response:
o Regarding the comment on the optimism suggested by designing the soil
alternatives on "sparse soil data", Mr. Rosenbloom required the
analysis be conducted to the degree prescribed regardless of the lack
of data for basis.
o In the PGA SVE Pilot Study, 99Z of the air removed from the uncapped
site extraction well was removed from within 200 feet of the
extraction well (Appendix S, p. 131).
o Each SVE extraction well has been located at the center of the
highest maximum predicted mean TCE concentration in the vadose zone
(Figure 1.6). The SVE extraction well will be most effective ir.
these locations, exerting the greatest vacuum nearer the well.
o In the comments on the March, 1989 version of the RI/;FS, Unidynamics
was criticized for using a 75-foot radius of influence; inferring
that the 75-foot radius was too conservative. This comment made
further reference to the SVE pilot test at the southern end of the
PGA site and inferred that a 150-foot radius of influence was perhaps
more appropriate. The comment was noted and used to prepare the June
supplement. (See Comments on the March, 1989 RI/FS by CH2M Hill;
comment number 26. Page 5-10, Section 5.2.2.1).
The air inlet wells will be used to evaluate the SVE radius of
influence. A field determination will be made as to whether a
150-foot or greater radius of influence has been attained.
o A method to evaluate the effectiveness of the SVE system is dependent
upon the soil cleanup standards. The PGA soils sub-committee is
still evaluating soils cleanup standards. It is not possible to
design a system to evaluate cleanup effectiveness until the cleanup
standards have been defined. This is a design detail that will be
addressed in the final design task if this alternative is
implemented.
-------
comments dated 7/6/89
-Page 8
SPECIFIC COMMENTS
Page 2S-1—Bullets; The area in the vadose zone that contains 99
percent of VOC contamination should be a target area.
Response:
o The basis for identifying target areas was specified in a letter from
Hugh Barroll (EPA) to M. Corash dated May 10, 1989.
o The area in the vadose zone that contains 99 percent of the VOC
contamination was never mentioned as a criterion in the letter or in
subsequent directions from EPA.
Page 2S-2—Top of Page: The conversion of ug/1 TCE soil gas to ug/kg
TCE in soil is based on assumed porosity and bulk density values. To
make absolute conversions with assumed values for soil properties is
incorrect.
Response:
o Commentator must be referring to 'Page 2S-4—Last Paragraph', where
the conversion is discussed.
o The conversion was requested by Jeff Rosenbloom of the EPA.
Page 2S-B—Last Paragraph-Interpretation; Other VOCs are present in the
soils at UPI, including MEK, TCA, xylenes, ethyl benzene, toluene, and
acetone. Of these compounds, MEK and acetone may be difficult to
extract with SVE. The presence of compounds listed are generally
associated with the occurrence of TCE, except for the borings in the
vicinity of Waste Facilities 7 and 11, the drum storage area, and boring
SCD. The interpretation and discussion does not address the other VOCs
present in the soil.
Response:
o The commentator must be referring to Page 2S-3.
o The analysis does not address the other VOCs in Che soil. However,
it is apparent from the response to Comment 9 that the other VOCs
will be amenable .o treatment.
o We did not see toluene listed on Tables 2.7 or 2.8 of the RI
summarizing detected VOCs during Stage I or Phase 11 programs.
Xylene is listed.
It is not clear whi,. is meant by ... "The interpretation and discussion
does not address the other VOCs present in the soil". Finally, the PGA
Committee has yet to determine the answer to two basic issues which are
relevant here:
-------
Responses co CH2M Hill '
commencs dated 7/6/89
Page 9
I. What is an acceptable level of cleanup of the soil; and
2. What method of monitoring to determine achievement of that level is
appropriate.
Page 2S-18—First Paragraph: Excavation and treatment could be retained
for localized areas where MEK and acetone are present.
Response:
This comment provides no guidance as to why retention of excavation is
needed. Absent the pending results from the PGA soils committee there
is no evidence that any localized areas are of concern. (Also see
response to Page 2S-B.)
o All VOCs will be removable by SVE system operation and excavation and
treatment is not deemed necessary.
o A compound's relative soil volatility is proportional to its vapor
pressure and inversely proportional to a root of its molecular weight
(The Hazardous Waste Consultant, November/December 1986). The
relative soil volatility property does not incorporate the solubility
of the compound as liquid phase mass transfer coefficients do. Thus
SVE could be expected to remove all volatile compounds regardless of
their ability to be removed from a liquid phase.
Indeed, ketones have relative soil volatilities greater than TCE.
Relative dry soil volatilities at 77°F are listed as: 21.5 for TCE,
10.5 for MEK and 72.5 for acetone. Relative wet soil volatilities
are listed as: 6.3 for TCE, 10.6 for MEK and 26.3 for acetone.
Three options for treatment of excavated soils are listed in the
Feasibility Study (summarized in Chapter 5, Table 4.3). Each of
these options are further evaluated on the basis of their
effectiveness in meeting contaminant reduction goals while protecting
human health and the environment, implementability in terms of
securing required governmental approval and the ability of disposal
or equipment services to treat the contamination and, finally, cost.
The results of this evaluation process is found in Chapter 5, Table
4.7 of the Feasibility Study.
Page 2S-18—3.1 Soil Excavation; If additional sampling is performed to
evaluate the areal extent of VOCs that are not easily removed by SVE,
excavation may become a viable alternative*
Response:
(Also see response to Page 2S-B.)
o See response to preceding comment; acetone and MEK would be removed
by SVE.
-------
Responses Co CH2.M Hill
comments dated 7/6/89 - - "
Page 10
o When soil cleanup standards are determined then additional sampling
may be required.
o Excavation is not a viable alternative for the UPI site.
Page 25-22—Last Paragraph: SVE well construction, particularly depth,
is best determined on site.
Response: The SVE well design presented should be considered
preliminary and is based upon the SVE pilot study at the former GAC
facility. Final design, if this alternative is determined necessary,
will account for site geology and contamination at the boring location.
Page 2S-24—Second and Last Paragraph; If excavation and SVE would be
difficult to implement, why doesn't UPI propose another alternative?
Response: It has been Unidynamics Phoenix, Inc.'s position that no
action is required. The soil "contamination" does not represent a
health and safety risk nor a threat to groundwater. Any invasive
technology would be difficult to implement in Target Areas B and C
because of ongoing manufacturing activities and safety requirements. It
is the invasive nature of any soil contamination collection option that
renders it difficult to implement within this area. The only
non-invasive soil option consistent with protection of the environment
is S-0: No Action.
Page 2S-27—Table A-l; A breakdown of O&M costs presented in a table
would be appropriate.
Response: Comment noted. A breakdown of O&M costs will be included in
the cost estimate listings on pages 2S-28 and 2S-29.
Page 2S-29—Target Areas B & C; Since SVE in Areas B & C will be
difficult to implement (page 25-24), where are these extra costs
mentioned?
Response: The difficulty in implementing SVE in these areas is the
disruption of ongoing manufacturing activities in the area. Final
design review may reveal specific equipment requirements or dictate
relocating equipment due to the nearby manufacture of explosive
materials. Increased costs would be estimated at that time.
-------
s3 a © —
July 6, 1989
VIA FEDERAL EXPRESS
Jeff Rosenbloom
Remedial Project Manager
U.S. Environmental Protection Agency
Region IX
215 Fremont Street
(T-4-2)
San Francisco, California 94105
Re: Phoenix-Goodyear Airport Superfund Site:
Comments of Goodyear on the RI/FS
Dear Mr. Rosenbloom:
This letter sets forth the comments of The Goodyear Tire &
Rubber Company ("Goodyear") on the Environmental Protection
Agency's ("EPA" or "the Agency") June 7, 1989, Public Comment
Draft Final Remedial Investigation/Feasibility Study ("RI/FS")
for the Phoenix-Goodyear Airport ("PGA") Superfund Site. The
Agency originally stated that the comment period closes July 7,
1989, but as indicated below, we understand that this period will
remain open to address additional information not yet contained
in the Public Comment Draft RI/FS.
At the outset, Goodyear would like to note for the record
that it entered into a Consent Decree with the Agency [dated
October 24, 1988] to undertake source control measures for a
portion of the shallow groundwater (referred to as Subunit "A")
that underlies the PGA site where the highest concentrations of
trichloroethylene ("TCE") and other volatile organic compounds
("VOCS") have been found. The Department of Defense, acting
through the U.S. Army Corps of Engineers, Omaha District, also is
participating in this source control measure. While Goodyear
continues to adhere to the schedule in the Consent Decree for the
performance of this work, several unanticipated field conditions
have been encountered that have required adjustments to this
schedule. Goodyear believes that its experience in
implementation of this operable unit has provided extensive
further information on the physical conditions at this site. It
-------
also has served to recognize the need to implement a remedy of
this type with a reasonable degree of flexibility in order to
adjust to varying site conditions that might occur during remedy
implementation. Goodyear requests that all reports, data,
correspondence and other related material transmitted to EPA
during the implementation of this operable unit be included in
the record for this final remedy.
The Public Comment Draft RI/FS contains an Endangerment
Assessment for the PGA site that concludes that there is minimal
risk to humans of exposure of TCE and other chemicals at this
site because (1) the contaminated groundwater in Subunit A is
currently not being used for drinking water; and (2) the drinking
water for the Cities of Goodyear and Avondale currently meets all
federal and state standards. Goodyear concurs with this
assessment and recognizes that the proposed plan of action
envisioned by this final remedy is intended to prevent the
migration of potential future contamination into that groundwater
that might provide a future source of drinking water if these
areas expand. Thus, it is Goodyear's position that there is no
imminent and substantial endangerment at this site.
Goodyear wishes to note for the record that the June 7, 1989,
Public Comment Draft RI/FS did not contain the State of Arizona's
groundwater model nor a final version of the vadose-zone
transport calculations. The State of Arizona groundwater model
was not received by Goodyear until late May, and the refined
vadose-zone transport calculations were not received until
June 23, 1989. As a result, Goodyear has not been able to fully
evaluate the RI/FS within the three-month period otherwise
allotted by EPA for comment. Therefore, the comments provided
here are preliminary in nature and refer only to the June 7,
1989, RI/FS. Goodyear specifically reserves its right to comment
on the State of Arizona's groundwater model and the vadose-zone
transport calculations and will do so within three weeks of
receipt of this information.
In addition, Goodyear has failed to receive other supporting
data for the RI/FS from the Agency. In particular, EPA has not
yet developed the detailed cost estimates for the various
proposed alternative remedies. Technical discussions concerning
the probable mass of TCE in the soil and the procedures for
determining the specific area for cleanup and the termination
point for cleanup are not even scheduled to occur with the Agency
until July 7, 1989, the date the original comment period
officially closes. Thus, Goodyear will not be in a position to
respond to these aspects of the RI/FS until two or three weeks
following receipt of the missing information and discussions with
the Agency. Goodyear also specifically reserves the right to
comment on these aspects of the RI/FS.
-------
- 3 -
It is Goodyear's position that the failure of the Public
Comment Draft RI/FS to incorporate complete supporting
documentation has effectively denied Goodyear its right to
comment on the proposed RI/FS in accordance with Section
113(k)(2)(B) of the Comprehensive Environmental Response,
Compensation and Liability Act, as amended ("CERCLA"). CERCLA
Section 113(k)(2)(B) provides that affected persons must have a
"reasonable opportunity to comment and provide information" on
the RI/FS. Judicial review of the selected remedy at a site is
limited to the administrative record, CERCLA Section 113 (j) (1).
Thus, absent the ability to exercise its right to comment on the
RI/FS in accordance with CERCLA, Goodyear is denied the right to
adequately participate in the development of the administrative
record: i.e., the only record that can be relied upon in any
subsequent challenge to the selected remedy.
In the monthly technical meetings with Goodyear personnel and
its consultant, Kaiser Engineers, Inc. ("Kaiser"), EPA has stated
that the comment period will be extended beyond July 7th for a
reasonable period of time to allow Goodyear to review and comment
on any missing material. If the missing data are not in a form
that would permit comment by Goodyear in the near future,
Goodyear strongly suggests that EPA extend its September 30,
1989, deadline for issuing the Record of Decision ("ROD") for
this site. While Goodyear realizes that the Agency has scheduled
the issuance of the ROD to correspond with the end of its fiscal
year planned accomplishments, a ROD cannot be issued if
interested parties have not had an adequate opportunity to fully
comment on the proposed remedy and based on the information in
the administrative record, the proposed remedy is not
cost-effective.
The following discussion outlines Goodyear's general comments
on the June 7, 1989, RI/FS. Detailed technical comments are
presented in an attached Appendix. See Attachment A.
TCE Residuals in Soils
To remedy soil contamination, the Public Comment Draft Final
RI/FS offers two alternatives: using an asphalt concrete cap and
soil vapor extraction ("SVE"). EPA has estimated that 115,000
pounds of TCE are present in the soil. For several reasons
Goodyear's consultant, Kaiser, believes that EPA has
overestimated the amount of TCE residuals in the soils. First,
the soil vapor surveys put the soil column under vacuum, which
leads to higher TCE vapor concentration to soil concentration
ratios. Second, the conversion from soil vapor to equivalent
total concentrations erroneously assumes the existence of
saturated conditions with an equilibrium falling between the soil
-------
- 4 -
sorbed state and dissolved state and dissolved state and
vaporized state. Conditions allowing such conversion simply do
not exist at the PGA site.
The conversion also assumes a single discre-e value for the
soil-water partition co-efficient based on an :organic fraction..in
soil of 0.5%. Much of the matter in the soil column, however, is
likely to be sand and gravel with little organic content. The
ADWR model has assumed no retardation (Kd=0) for the aquifer. As
the Kd approaches 0.0, the ratio of soil sorbed TCE to soil vapor
TCE approaches 0.0. Thus, estimates of TCE residuals in the soil
would be much smaller if the Kd equals 0.0 as estimated by ADWR.
Kaiser believes that a more .accurate estimate of TCE
residuals would be between 20,000 to 30,000 pounds; of which
1,000 to 5,000 pounds would be sorbed onto the soil particles or
contained in interstitial water and between 15,000 to 29> 000-
pounds present as vapor in the pore space in the soil.
Because EPA has overestimated the amount of TCE in the soil
and because no federal or state standards for the cleanup of soil
contaminated with VOC's exist, Goodyear advocates the adoption of
specific methods and criteria to address the field conditions as
they are encountered during the cleanup process itself. This
approach will require a consensus on acceptable cleanup levels
based on more realistic estimates of soil contamination. To
further emphasize this concern, Goodyear notes that if EPA
proceeds with its current soil-vapor extraction rate, this
remedy, as presently conceived, may produce the undesired outcome
of extracting TCE up from the groundwater through the soil.
Because of the uncertainty over the actual mass of residual
TCE in the soil and the operable migration pathways, Goodyear
recommends a "decision tree" for determining when TCE soil
evacuation can be terminated. See attachment B. While Goodyear
understands that EPA has agreed to this approach in concept at
various technical meetings, the parties have not yet agreed on
the actual criteria levels that would result in terminating the
soil extraction process at a certain point or the target area for
cleanup. A meeting to discuss these various target cleanup
levels has been scheduled for July 7, 1989. If this meeting
achieves any consensus on the decision-tree approach, Goodyear
reserves the right to comment on the target cleanup levels
established for the decision tree. Until these target cleanup
levels are established, neither EPA nor Goodyear can estimate the
potential costs involved with the soil evacuation remedy or, more
specifically, whether soil extraction is a more cost effective
remedy than capping.
-------
- 5 -
Groundwater
The Public Comment Draft RI/FS offers four alternatives to
address the remaining groundwater contamination at the site: (1)
pumping and treating at an accelerated rate using existing wells •
to meet existing standards; (2) pumping and treating at an
accelerated rate using new wells to meet existing standards; (3)
pumping and treating at an average rate using new wells to exceed
existing standards; and (4) pumping and treating at an
accelerated rate to exceed existing standards.
At the outset, Goodyear notes that the existing maximum
concentration level ("MCL") under the Safe Drinking Water Act for
TCE is 5 parts per billion (ppb).i7 As the Agency's risk range for
Superfund remedies is 10~ to 10~ and as the proposed revisions
"to the National Contingency Plan ("NCP") no longer require
consideration of alternatives that exceed standards (53 Fed. Reg.
51506, December 21, 1988), Goodyear believes that alternatives 3
and 4 would exceed the requirements of CERCLA, and would not be
cost effective.
Alternatives 1 and 2 both focus on meeting existing
standards, but require pumping at an accelerated rate. Goodyear
believes, for reasons discussed in greater detail below that the
preferred alternative from a cost effective perspective should be
one that pumps the contaminated groundwater at an average rate
using existing wells.
EPA's discussion of groundwater in the RI/FS is flawed in
several respects. Principally, EPA's final remedy has failed to
take into account how contamination in Aquifers B and C will be
eliminated by the operation of the interim remedy in Aquifer A.
Second, EPA has failed to establish this pumping rate using any
valid groundwater model. Indeed, it appears that the Agency has
failed to use any existing groundwater contamination model, such
as the ADWR model, at all. To our knowledge, no work is
scheduled to refine the ADWR conclusions. Because the Agency has
failed to use the ADWR model (or for that matter any valid
model), the current RI/FS discussion of groundwater contamination
is completely inadequate as a basis for selecting a remedy.
Consequently, it has been virtually impossible for Goodyear to
evaluate the selected alternatives. Goodyear urges EPA to
recalculate the groundwater scenario using the ADWR model and
specifically reserves its rights to comment on EPA's revised
groundwater discussion. Finally, recognizing that federal
standards for TCE exist, Goodyear believes there should be a
process to terminate pumping and treating groundwater after
certain action levels are met.
-------
- 6 -
Although EPA apparently favors air stripping over carbon
treatment as part of this overall final remedy, Goodyear
nevertheless desires to emphasize the efficacy of air stripping.
As EPA is aware, Goodyear sought modification of the Consent
Decree for that part of the operable unit addressing pumping and .
treating Subunit "A" because it felt that carbon treatment far
exceeded the applicable, relevant and appropriate air quality
standards for this area, and was consequently nat"a-'cost-
effective alternative. This position was based on a
sophisticated risk assessment of area-wide air emissions that was
performed by ICF Technology, Inc. Goodyear is including this
risk assessment and a copy of its correspondence to EPA on this
subject as part of these comments (Attachment C).
Finally, none of the groundwater alternatives currently
envision that any of the treated groundwater would be used for
any purpose other than reinjection. If other viable uses become
apparent during the implementation of this remedy, Goodyear notes
that water rights administered by the State of Arizona will have
to be dealt with, and that a reasonable degree of flexibility
should be factored into implementation of the final remedy to
meet these potential requirements.
Conclusion
Goodyear and its consultant have reviewed the June 7, 1989,
RI/FS for the PGA site and have found the document to be flawed
in several major respects. Moreover, as the June 7, 1989, draft
final RI/FS currently exists, it provides an inadequate basis for
commenting on, or selecting, a cost-effective remedy for the PGA
site. Goodyear would be happy to answer any questions that the
Agency may have on these comments.
Sincerely,
Manager
Environmental Engineering
David L Chapman
pah
Attachments
-------
89187RDS0690
ATTACHMENT A
TECHNICAL COMMENTS
1. P 2-37. The discussion of metals in soil encompasses all metal
data generated regardless of the probable source of the metal
or background levels in the area of the PGA. This discussion is
particularly misleading with respect to arsenic since natural
arsenic levels are sufficiently high to generate risk levels of
concern and there is no record of use of arsenic on site. The
failure to segregate site-related contaminants from naturally
occurring ones results in soil ingestion risks being driven by
arsenic which cannot be remedied since it is ubiquitous, in the
native soil. A few statements to .this effect would prevent the
reader from being misled about site-related risks.
2. P 2-40. No attempt has been made to differentiate Cr(Ill) from
Cr(VI) or leachable chromium from fixed or insoluble chromium.
As a consequence, total chromium values are reported and used for
the purposes of estimating public health impacts even though availa-
bility and valence state greatly effect the nature and magnitude
of risks.
P 2-54. An estimate of the inventory of TCE in soil of 450 Ibs
was made from existing soil boring data, when an amount equal to
this was removed during pilot soil evacuation work, a second
estimate was attempted using soil vapor data. The latter estimate
came to as much as 115,000 Ibs depending on the assumptions made
with respect to vertical distribution of TCE residuals. The
algorithm used to calculate total soil TCE mass from soil vapor
data relies on an assumed equilibrium condition between soil-sorbed
TCE, water-bound TCE, and soil vapors.
For simplification, a single partition value was used to calculate
soil/water ratios. This value was also used in conjunction with
the Henry's law constant to predict soil/vapor ratios. The par-
tition value selected was based on a prescribed soil organic level.
Use of any value other than 0.0 contradicts the assumptions made
by the Arizona Department of Water Resources (ADWR) in preparing the
ground water model for the site. While the ADWR assumption is
probably overly conservative, an assumed constant value throughout
a 60 foot depth is also misleading. It is highly likely that deep
sands and gravels will have little or no affinity for the TCE.
Hence, use of the algorithm will overpredict soil-bound TCE from
the existing TCE vapor data.
-------
- 2 -
The likelihood of overprediction is illustrated by analysis of
the existing data. The highest soil vapor values were found in
the area of the soccer field. Borings in that same, area revealed
no measurable TCE in subsoils. Hence, the algorithm is assigning
TCS at significant concentrations to soils that have no evidence
of contamination. Similarly, soil vapor readings from the area
of the Phillips well were as high as 1.7 ug/L even through this
-property is 3 miles from the site. These vapor- levels- are either
'derived from other sources or reflect the ground; water plume at
that point. There is no evidence that they are associated- with
soil contamination.
4. p 2-61. Calculations are made to estimate the total volume of
soil in excess of Arizona Department of Health Services (ADHS)
soil action levels. These volumes are meant for use in determining
the cost of remedial action. The-volumes are misleading, however,
since they encompass all soils and subsoils with voc concentrations
in excess of the action level. The action level was devised for
surface soils, not deep subsoils. Most TCE residuals lay 20 to 30
feet below the surface. Alternate action levels- are needed for
these soils on the basis of their ability to affect ground water
quality.
5. P 2-61. Vadose zone calculations are made suggesting that 16,000
Ibs of TCE will move to the ground water in 20 years. These calcu-
lations are based on an assumed recharge that is without documen-
tation. They also appear to take no recognition of unsaturated
zone transport times. Using EPA time-of-travel algorithms, recharge
at 0.32 in/yr would take 117 years to move 20 feet downwind under
current conditions. If the TCE has a partition coefficient of 0.49
L/Kg, its travel time would be retarded by a factor of 2.6 and
hence would be 304 years.
6. P 3-46. The risk calculations are based on current TCE concentra-
tions at various wells around the PGA site. No attempt was made to
use the ADWR model to see how those concentrations will change over
time. Since cancer risks are based on 70 years of exposure, the
assumption is tantamount to saying that the ground water at any one
well will not see any appreciable change in TCE concentrations over
a 70 year period. That is unrealistic. Simple application of plume
size and the estimated velocities in the affected aquifier suggest
the concentrations will drop an order-of-magnitude in seven years.
If that does occur, the actual risk at the site will be one tenth
that predicted in the RI/FS. The analysis also fails to consider
the affects of the Operable Unit 16 remedy which is curreiiLly under
construction.
7. P 3-46. well logs from construction of extraction and injection
wells for the Operable Unit 16 remedy suggest that the boundaries
between subunits A, B and C are not always distinct and then in
some areas, the units may be indistinguishable. Previous descrip-
tions imply rather clear cut interfaces which is misleading.
-------
8. P 4-1. Risk estimates for suspended particulate are based on
current emission rates being sustained over a 70 year period. A
simple calculation shows that in a period of 7 years, the finer
suspendable particles will be depleted to a depth of 1.5 cm.
This in effect will leave the larger, nonsuspendable particles
to armor the surface and minimize further resuspension. As a
consequence, risks will actually be an order-of-magnitude less than
predicted. The bulk of the risk from suspended particles is
attributable to arsenic in the soil. Since arsenic is naturally
-present and not a site-related contaminant,- the risk- calculations
provide a misleading picture of incremental risk and risks that
can be addressed by a site remedy. All soils in the area pose
the same level of arsenic driven risk.
•y. P 5-41. The ultraviolet-ozone oxidation process is dismissed
prematurely. Recent studies show.this process to be very effective
in removing organic contaminants from water. In areas where air
stripper emissions must be treated with carbon, the UV-ozone process
•• - can be cost competitive.
A
10. P 6-13. Target Area 1 is inappropriate. ADHS action levels were
designed to address surface soils, not subsoils 20 to 30 feet
beneath the surface. IF a target area is to be defined using
ADHS action levels, it should be based solely on TCE concentra-
tions in surface soils.
Target Area 3 is not based on any defensible rationale. No
attempt is make to relate soil vapor concentrations to site risk
values. Since soil vapor results do not correspond with subsoil
-oncentrations of TCE, the use of soil vapor to delineate a target
area is illogical. At a minimum soil vapor values should be con-
verted to equivalent soil concentrations and the target area defined
on the basis of the latter.
11. P 6-21. The discussion of the capping alternative appears to
•contradict other portions of the RI/FS. The implication of this
discussion is that recharge is insignificant with respect to TCE
movement. And yet, the calculations of vadose zone movement and
soil residual effects on ground water quality are based on a
prescribed recharge rate of 0.32 in/year. Either recharge is
driving TCE downward and capping will minimize or prevent this
migration, or recharge is insignificant and sub-soil contamination
can be left in place without remedy.
12. P 8-2. A'very simplistic analysis is employed to calculate aquifer
flushing times. This is difficult to explain since a great deal of
money has been spent developing a sophisticated ground water model
to predict flushing times and plume movement. The RI/FS should
rely on model results for flow and transport predictions.
-------
- 4 -
13. Figure 8-3. The contaminant plumes have been depicted as large
areas joining points wherever VOGs were detected in ground water
without regard to the relative concentrations at adjoining wells.
Geostatistical analysis should be used to prepare these plots.
The relatively high values at the Phillips well and lower concen-
trations at points between Phillips and the site open the possibil-
ity of multiple sources or a more concentrated transient plume that
-is passing by Phillips to be followed by water of better quality.
-Since risk was estimated on the basis of continued -exposure to
current levels, a better characterization of the :actual'plume could
• - have a big impact on conclusions concerning risk and the nature of
required remedies.
14. P 8-30. Simple equations are applied to estimate ground water
travel times. The ADWR model was developed to provide much more
accurate predictions of travel times and should be employed for
that purpose.
15. P 8-36. A simplified approach is taken to calculate the time
required to achieve clean up. Once again, the ADWR model should
be employed for this purpose. Furthermore, the estimates do not
consider implementation of the Operable Unit 16 remedy or continued
inputs from the vadose zone. This static evaluation of aquifer
cleansing is unrealistic.
16. P 9-7. The analysis of end use options for the treated ground
water does not give ample consideration to problems associated
with water rights. A brief discussion is given of water rights
after discharge. However, it is not clear if the water is currently
owned by a party who can subsequently dictate where the treated
water should go. If the City of Phoenix or some similar entity
owns the ground water, they may not allow it to be delivered for
private or public use by other entities. A much more thorough
evaluation of ownership is required before discharge alternatives
can ce considered.
17. P 10-1. The options for design of the ground water extraction
system should be evaluated using the available models of the
local ground water. A simple water balance approach fails to
consider the Operable Unit 16 remedy and the complexities of the
aquifer. With sophisticated tools readily available to support
the analysis, reliance on simple approaches is indefensible.
-------
ATTACHMENT B
SOIL EVACUATION TERMINATION LOGIC FLOW
ENTER
YES
DOES
ESTIMATE TCE
MASS EXCEED LEVEL
REQUIRED FOR
GW (TCE)
>ARARS?
SHUT DOWN SYSTEM
MONITOR GW
AND SOIL VAPOR
NO
SHUT SYSTEM DOWN
ALLOW SOIL VAPOR TO
RETURN TO STEADY STATE
DOES
GW (TCE)
RETURN TO LEVELS
>ARAR?
SOIL VAPOR (TCE)
HIGH ENOUGH FOR
CALCULATED MASS TO
CAUSE GW (TCE)
>ARAR?
EXIT
YES
-------
-CNBY L. OIAMONO
ALie»T j. arvCBiooc. at
3AO» N. IAISC
• AHOI.O «IMMfUMAN
CHUUTOPHCH M.
.
AI.CKANOCR «. aiCRCK
JOHN N. HANSON
ANOACW C.MISHMIN
•IILLiAM N. HCOCMAN. J ».
JAINCS SWATHMCT, 31
CTNfMIA A. taCW5
«AOV. s. souaotAu
JOHN 9. JUTTMANN
DON s. SCBOCSIN
SA0V J. SMITH
SCNJAKIN r. WILSON
aottar SOAQCR
9ICHAIO S. 3AVIS
FMOHAS aiCMiCHi
SUS IAUMAN
J. 3ANICL
orCOUMJCL
JOHN raCNCH 01
a. THCOOOKC HUMC
CONSULTING CCONOMIST
-i- j. rozzi
ATTACHMENT C
LAW OFFICES
BEVERIOGE & DIAMOND, P. C.
1333 New HAMPSHIRE AVENUE. N. W.
WASHINGTON, D. C. 2OO36
(2O3) 32S-02OO
TCLECOPICB faoa) 320-023*
TELEX 3723339 aevoiA WSM
SUITE IZO2
IOI PAPK AVCNUC
NCW VORK. N. T. IOI7S
(212) 987-3389
aevepioct & DIAMOND
ONC smoae oukZA
FOOT tee. N. j. 07O2*
(2OI) S«S-«I82
•DITCH 1 01*1 CT OlAv, NUMtCft
(202) 429-2726
December 1, 1988
OCAM M. CANNON
VIRGINIA s-ALaac
OONALO j. PATTtas
STCVCN f. 1IOSCH
•HCNOA MALLOBY
MAUK A. r
MA A. u
THOMAS C. JACKSON
KATHBTN C. SZMIJSZHOVIC:
HABOLO I.. SCGAL*
OCTCK J. 1ACBIBANTI
3USTIN B. OBOWA'
*CNNCTN S. AAUFMAN
CHABLCS '• SACIV1N
CHABLCS
-ABC A.
•••»••*• *• t fc^—» 1 fcl-'.J
LISA M. MAHTIN-
CHCBI C. VKOLf"
IHBISTOBMCB v». MANONC*
STCVCN M. JAWCT:
OAVIO H. rBicbuhNO
ALISON A. *CBtSTtB
JOHN 3. 3IGUO
ELLIOT 0. COCB
SUSAN j. Noaosrarr
OC1BA L. BOTHICRG-
DOUGLAS 8. wCINrif.a.
AABON H. 3OL38CBG
r. CBAIO "HOBLCT
CBAiG O. SALLJ
JOHN T. S. W!-.kiAMS«
SUSAN '.. rrxaoN
SHCLwCT V. LUCAS
• NOT AOuirrto .
Jerry Clifford
Assistant Director of Superfund
Region 9
U.S. Environmental Protection Agency
215 Fremont Street
San Francisco, CA 94105
Dear Mr. Clifford:
Goodyear appreciated the opportunity to meet with you, your
staff and representatives of Region IX's Air Programs on
November 30, 1988, to review the current project at the
Litchfield PGA site and to discuss the extent to which carbon
treatment should be required as part of the operation of the
first seven extraction wells associated with this operable
unit. The dialogue was informative and constructive, and this
letter follows-up on those discussions with a specific proposal.
As we indicated in that meeting, Goodyear requests,
pursuant to Paragraph XXV. of the Consent Decree that was
entered on October 31, 1988, that a modification to Paragraph
VII.C.5.(c) of the Consent Decree be considered by EPA. This
request is based on information that was not available during
the time in which the Consent Decree was negotiated. It was
discussed at our meeting and is being formally presented to you
by this letter.
oe-
-------
BeveRioce & DIAMOND. P. C.
Mr. Jerry Clifford
Page 2
December 7, 1988
Goodyear recommends, as a result of this new information
(which is discussed in greater detail below) that any
requirements for carbon treatment that may exist in the current
Consent Decree be formally eliminated. In the alternative,
Goodyear requests that the issue of carbon treatment be
deferred for at least two years, until the final remedy has
been selected and designed. As we indicated at the November
30, 1988, time is very much of the essence with respect to this
request for modification as Goodyear is required, pursuant to
Paragraph VII.D.5. of the Consent Decree, to submit a proposed
final design to EPA by January 11, 1989. This issue relates
significantly to how that design will be developed and
presented.
As you are aware, Goodyear prepared a set of comments
relating, among other things, to this issue which was submitted
to the Department of the Justice ("DOJ") for consideration
during the period of time in which the Consent Decree had been
lodged and made available for public comment. Regretably,
these comments were not considered before the Consent Decree
was signed and filed on October 31, 1988. However, we are
incorporating these comments as an enclosure to this letter
(Enclosure 1), as they address Goodyear's position concerning
the applicability of Arizona State requirements to the issue.
In this letter, we cited a number of EPA documents
("Guidance on Feasibility Studies under CERCLA" dated April,
1985, page B-19 and the "Superfund Public Health Evaluation
Manual" dated October, 1986) to observe that the risk range of
10~4 to 10~7 is used by EPA to determine adequate
protection of public health and the environment when there are
no national standards that otherwise would establish an
appropriate level of cleanup. We also note that this risk
range has been presented by EPA for comment in its proposal for
inclusion in revisions to the National Contingency Plan which
were announced on November 17, 1988; but EPA also has requested
comments on reducing this risk range from 10~"4 to 10~7 to a
range of 10"4 to 10"6. We indicated in our October 19,
1988, letter to DOJ that "the health risk of exposure to the
air emissions from the air strippers, without carbon
absorption, is no worse than 10~4, and also stated that
Goodyear would be developing additional data to support this
position which would be forwarded to you under separate cover.
This data was discussed with you on November 30, 1988, and is
incorporated into this letter as Enclosure 2.
Goodyear's consultant, ICF, Inc., performed a risk
assessment of the release of volatile organic compounds
("VOCs") into the air with air stripping'but without carbon
absorption. Taking trichloroethylene ("TCE") alone, the cancer
-------
BEVERIOGE & OIAMONO. P. C.
Mr. Jerry Clifford
Page 3
December 7, 1988
risk is less than 1 x 10~7. Indeed, at 100 meters from the
extraction wells, the cancer risk is .74 x 10~7, and then
diminishes significantly as one proceeds away from the site at
300 meter, 700 meter and 1500 meter increments. When one
incorporates the cancer risk of dichloroethene" (DCE) into the
equation, the combined risk for both substances is less than
10~6 (actually, .24 x 10'6 at 100 meters).
As we indicated in our meeting, the fundamental objective
of Superfund cleanups is to adequately protect public health
and the environment. While we recognize that a great deal of
discretion exists within EPA in determining what is adequate
protection, and that this discretion is in large part bolstered
by somewhat conflicting criteria within the Superfund
Amendments and Reauthorization Act ("SARA") (which EPA
describes in the preamble to the proposed revisions of the NCP
as a "dynamic process,") we submit that the fundamental
objective should be adequate protection of public health in the
most cost effective manner. EPA guidance and proposed
revisions to the NCP subsequent to enactment of SARA have
provided various bases for determining what is adequate
protection of public health and the environment. First, EPA
uses applicable, relevant and appropriate federal and state
requirements ("ARARs"). While there are technology based
standards relating to Arizona's State Implementation Plan
("SIP") for sources emitting TCE contaminants, Goodyear does
not believe that they can be interpreted as requiring carbon
absorption in the PGA case for the reasons discussed in greater
detail in Enclosure 1. However, those standards are not health
based; rather, they are technology based. As to health based
standards which also are intended to address the adequacy of
public health protection, we believe that we have demonstrated
to you and your staff that air stripping from these extraction
wells will more than adequately achieve that purpose without
the.need for carbon treatment.
During our meeting, mention was made of a developing policy
within EPA concerning the requirements for Superfund remedies
located in non-attainment areas. While Goodyear appreciates
the issue and is very sympathetic to the air pollution problems
that exist in certain areas of the country, including Phoenix,
we can find no legal basis for the application of a
non-existent (but emerging) EPA policy in this area. In
addition, we question whether or not such a policy would fall
within the cost-effective criteria of SARA, if it can be
demonstrated that air emission controls are not required to
adequately protect public health and the environment.
During our meeting, concern was also expressed as to
whether remedies established at other Superfund sites within
-------
BevERioce & DIAMOND. P. C.
Mr. Jerry Clifford
Page 4
December 7, 1988
the Phoenix, Arizona area would be brought into question if
Goodyear were not required to install carbon absorption as part
of the treatment of the extracted groundwater. We have
examined the sites that were mentioned, and offer the following
factors to distinguish each of them.
At the Indian Bend Wash Superfund site, we are informed
that the City of Scottsdale is operating an air-stripping tower
(at well no. 6) which is not equipped with emission control
equipment. According to representatives of Arizona's
Department of Environmental Quality and the City of Scottsdale,
the City is allowed to operate this air stripper without
emission control equipment because it emits less than 40 pounds
of VOCs per day, which is the threshold level for emission
controls under Maricopa County regulations. The City is
planning five to six additional air-stripping towers where it
does intend to install air emission control equipment.
According to the City, however, the reason for installing air
emission controls is due to the residential character of the
area and the request by neighboring citizens for air emission
control equipment, not because such controls would be required
pursuant to any regulation. Also, we are informed that the
City's future towers will be part of a final (as opposed to an
interim) remedial plan.
Another federal Superfund site in Maricopa County, Motorola
52nd Street, currently is in the planning stage. The Draft
Remedial Action Plan prepared by Dames & Moore (June 24, 1988),
indicates that Motorola is considering use of carbon absorption
emission controls in its air-stripping towers, although no firm
decision has been made. Dames & Moore anticipates that the
air-stripping towers will be located at Motorola's plant
facility. Because the plant facility already is subject to air
emission requirements, representatives of Dames & Moore believe
carbon absorption may be necessary for the air-stripping towers
to keep total plant air emissions below regulated levels.
Motorola's plan appears to be in its early stage (10%) plan,
and Dames & Moore indicates that plans to use carbon absorption
may change as the design progresses.
EPA apparently has allowed other -i^-stripping towers to
operate without emission controls in Pima County, Arizona so
long as those facilities met applicable air quality
regulations. We have been informed that the applicable
regulation in Pima County requires emission controls at
"miscellaneous" sources if VOC emission exceed 2.4 pounds per
day. Representatives of the City of Tucson and Hughes Aircraft
informed us of currently operating air-stripping towers at
federal Superfund sites that emit below the 2.4 pounds
requirement. Neither of these towers has been required to
-------
BEVERIOGE & DIAMOND. P. C.
Mr. Jerry Clifford
Page 5
December 7, 1988
install air emission controls, as VOC emissions did not exceed
the regulatory threshold.
"It "is significant that emission controls have not been.
required for air stripping units at state-lead remedial action
sites in Maricopa County where less than 40 pounds-per day of
VOCs are emitted. We provided you with the original of a
printout obtained from the Maricopa County Health Department
Bureau of Air Pollution Control. (A copy is attached for your
convenience/ Enclosure 3). The printout listed all stripper
facilities with potential emissions of less than 40 pounds per
day of volatile organic compounds which obtained air permits
during the calendar years 1987 and 1988. Of the sixteen listed
sites (eight of which emit VOCs at levels equaling or exceeding
the maximum of 10 pounds per day expected from Goodyear's
proposed facility), only one is equipped with air emission
controls: an air stripper at a Texaco service station at 305
East Thomas Road. That cleanup is managed by W.W. Irwin, Inc.,
of Long Beach, California. Long Beach is located in
California's South Coast air quality control district, which
district requires such emission controls for any facility
emitting over one pound of VOCs per day. w.w. Irwin has
informed us that it simply did not investigate the applicable
Maricopa County regulations and proceeded under the erroneous
assumption that a one pound per day limit applied in Maricopa
County. Such emission controls were neither required nor
requested by Maricopa County's Bureau of Air Pollution Control.
Maricopa County does not maintain air monitors in or near
the City of Goodyear or the Phoenix Goodyear Airport. It would
be difficult unequivocally to claim that the area immediately
surrounding the Phoenix Goodyear Airport would be in attainment
for ozone, if a monitor were placed there. Because it is
largely a farming area and the prevailing wind and weather
patterns in the Phoenix area are from west to east (thus
tending to carry ozone and other pollutants from the
metropolitan area eastward), it would not be unreasonable to
assume that Goodyear, which lies to the far west of Phoenix,
would be in attainment with regard to ozone levels, were a
monitor present at the airport.
In summary, this modification is based on the fact that we
did not have a risk assessment of the air emissions that would
occur without carbon absorption when we negotiated this Consent
Decree. Indeed, many of the numbers that form the basis for
this risk assessment were not developed until the completion of
the conceptual design. We believe that this information
clearly supports a view that, at a minimum, Goodyear should be
given the opportunity to defer any requirements for carbon
absorption until the overall requirements for treatment become
better known in the final remedy.
-------
SEVERIOGE & DIAMOND. P. C.
Mr. Jerry Clifford
Page 6
December 7, "1988
As was stated at the meeting, we recognize that many of the
requirements for this operable unit form the "cornerstone" of
the final remedy. But, at the same time, as
Section 121(d)(4)(A) of SABA indicates, ARARs and related
requirements do not have to be considered as part of an interim
.remedy. Equally relevant in these considerations is the need
to maintain a continuous and constructive relationship between
EPA and Goodyear over a considerable number of years. The
constructive relationship that we have sought to establish with
EPA in working on this project is based on the elements of
fairness and reasonableness that we believe now prevail, and
will continue to prevail in the long term future in which both
of us will be associated with this project. To request a
potentially responsible party, such as Goodyear, to invest
$300,000 - 500,000 in capital expenditures for carbon
absorption at these first seven wells, as well as an estimated
average of $90,000 per year for routine maintenance when
adequate protection to public health and the environment
already exist through air stripping based on EPA's existing
criteria, simply does not seem right.
Goodyear hopes that you take this request for a
modification in the spirit in which it is given. While we
recognize that the request follows closely on the heels of the
final Consent Decree, we would emphasize that the data to
support it did not emerge until completion of the conceptual
design, and that Goodyear has fulfilled every commitment in the
Consent Decree since it undertook the initial work in April,
1988.
Thank you for your consideration of this request and we
continue to look forward to working with Jeff Rosenbloom and
other EPA staff in the future.
Sincerely yours,
William N. Hedeman,
WNH/b
Enclosures
cc: Alexis Strauss (with enclosures)
Jeff Rosenbloom (with enclosures)
Hugh Barroll (with enclosures)
Barry Sandals (with enclosures)
David Chapman (without enclosures)
Mark Phillips (without enclosures)
Takashi (Wally Ito) Ito (without enclosures)
John Hill, ICF (without enclosures)
Rolf R. von Oppenfeld, Fennemore Craig (without enclosures)
lOSlq . . . .
-------
THE GOODYEAR TIRE & RUBBER COMPANY
1144 E. Market St.
Akron, Ohio 44316
(216) 796-3084
October 19, 1988
Assistant Attorney General
Land & Natural Resources Division . . .
Tenth and Constitution Avenue, N.W. ' '
Ben Franklin Station
P.O. Box 7415
Washington, D.C. 20044-7415
Re: United States v. The Goodyear Tire &
Rubber Company; D.J. Ref. 90-11-2-186
Comments of The Goodyear Tire & Rubber
Company on Proposed Consent Decree
Gentlemen:
The Goodyear Tire & Rubber Company (hereinafter
"Goodyear") hereby submits its comments on the referenced pro-
posed Consent Decree addressing the operable unit remedial action
at the Phoenix-Goodyear Airport Superfund site in Litchfield
Park, Arizona. " ..
Goodyear respectfully requests the Department of
Justice ("DOJ"), after consultation with the. Environmental Pro-
tection Agency ("EPA") to file these comments with the court
along with a concurrent motion to enter a judgment that is
consistent with modifications to the draft consent decree as
presented below.
Before addressing the two areas of major concern to
Goodyear in the proposed consent decree, Goodyear would like to
make a preliminary observation. Goodyear responded to the EPA's
notice letter concerning its willingness to enter into
discussions with EPA concerning the negotiation of the proposed
consent decree in a timely manner. However, the unique circum-
stances at this site, and in particular the involvement .of t.-.e
U.S. Navy as a potentially responsible party ("PRP") along vi:r.
Goodyear, raise'd significant legal and policy issues t.-.at
required resolution within the Deoartment cf Defense concurrer.tlv
-------
Assistant Attorney General
October 19, 1988
Page 2
with Goodyear's negotiations with E?A. Resolution of several of
these issues occurred through an alternative dispute resolution
("ADR") process between Goodyear and the Department -of -Defense,
represented by the U.S. Army Corps of Engineers, Omaha.. Distr ice,
which did not conclude until May 21, 1988. -• :.: . -;.
During this period of time from September 3, 1987 (the
date on which the notice letter was sent to Goodyear) to May 21,
1988, (the date on which Goodyear signed the consent decree),
Goodyear initiated the first phases of the work described in
Paragraph VII of the consent decree, and has submitted all work
elements required by Paragraph VII as if the consent decree were
effective and binding. This was done to ensure that Goodyear's
."(and -subsequently the Department of Defense's) commitment to
"address the problems at this site would not- be unnecessarily
delayed while waiting for full resolution of the exact provisions
of the filed consent decree. However, as Goodyear proceeded into
the conceptual design of this operable unit ("OU"), it became
aware of other alternatives associated with conducting this
interim remedy not known to all of us (EPA, Goodyear, and the
Department of Defense) during the development of the operable
unit feasibility study ("OUFS") that yielded EPA's Record of
Decision ("ROD") on September 29, 1987.
We emphasi2e this point to indicate that the changes
requested in the proposed consent decree that are outlined below
are changes that have evolved during Goodyear's voluntary perfor-
mance of the work elements displayed in Paragraph VII of the
proposed consent decree. While we do not believe that any of
these changes to the proposed consent decree would trigger, as a
condition precedent, a change to the ROD, we do believe that the
changes would further clarify the intent of all of the parties,
would be consistent with the ROD and the requirements of the
Comprehensive Environmental Response liability and Compensation
Act ("CIRCLA")/ as amended by the Superfund Amendments and
Reauthorization Act of 1986 ("SARA"), and .also would provide
adequate protection to public health and the environment in a
cost effective manner.
A. Disposal of Treated Water;
Our first proposed change relates to Paragraph
VII.C.5(a) of the proposed consent decree which reads as follows:
All water from the groundwater extraction
system will be treated and rsinjected. Treat-
ment shall assure that reinjected water will
meet federal and state standards for treatment
-------
Assistant Attorney General
October 19, 1988
Page 3
plant discharge levels prescribed in Table I
of the 1987 ROD'. During start-up activities,
extracted water to and from the" treatment
plant will be checked on a schedule as
provided for in the Operations and Maintenance
Plan submitted in accordance with subpara-
graphs D.8 and D.10.
This subparagraph of the consent decree was written
following the emphasis in the ROD that the only alternative for
disposing of the water that was. pumped and treated from Subur.it A
was to reinject the treated water back into the ground. This
section, as written, would require reinjection of the water and
would not permit consideration of other available'beneficial uses
of this groundwater.
Currently the natural background quality of Subunit A
water addressed by the OU is located is so poor that it is not
used for potable, agricultural, or industrial purposes. Tests
show average total dissolved solid concentrations of approxi-
mately 3,000 pom. The existence of industrial contaminants
slightly further degrades the extracted water's quality. As
presently written, the consent decree provides no option for
cost-effectively treating the water to manage the background
contaminants that remain after the water is treated to remove the
industrial contaminants of concern. If these background
contaminants can be economically managed, it could potentially
create the availability of additional water resources for use in
the Arizona desert.
The 1987 ROD incorporated the OUFS discussion of poten-
tial water disposal options. The OUFS indicated that disposal
options other than reinjection are not economically feasible,
although other uses may be desirable. Presently, the proposed
treatment water reinjection system calls for installation of 15
to 18 reinjection wells along with a distribution piping system.
The capital cost of this system will range from $500,000 to SI
million. There also will be a large operation and maintenance
cost associated with the reinjection system. The operation of
the reinjection system may pose substantial technical challenges
which are of concern to Goodyear. Goodyear believes, therefore,
that from a cost-effectiveness and technical viewpoint, an option
to create an economically usable water resource from the
extracted water may exist, or may arise at some point in the
future. Goodyear further believes the potential for managing a
presently non-usable water resource to create a viable water
resource should be encouraged and further explored, if determined
by Goodyear to be economically practicable. Of course, if sue.-.
-------
Assistant Attorney General
October 19, 1988
Page 4
an alternative proved to be feasible, it would have to be
consistent with the water laws of the state of Arizona, and
should be approved by che Arizona Department of Water Resources.
Therefore, Goodyear respectfully requests DOJ and EPA to consider
and support a modification to the consent decree to allow Section
.VH.C.S(a) to read as follows:
All water from the groundwater extraction
system will be treated. All treated water
from Subunit "A" will be reinjected, or in
the alternative, disposed of through an
economically practicable and beneficial use
on terms and" conditions approved by the
Arizona Department of Water Resources.
Treatment shall assure that reinjected water
will meet federal and state standards for
treatment plant discharge levels prescribed
in Table 1 of the 198*7 ROD. All water
disposed of through a beneficial use shall be
treated or otherwise meet all applicable
federal and state water quality standards and
criteria.
3. Air Emissions from Air Striooers;
Goodyear's second issue relates to Section VII.C.5(c)
of the proposed consent decree, which reads as follows:
Air stripping will be used to reduce volatile
organic compound ("VOC") contamination to
meet federal and state standards as pre-
scribed in Table 1 of the 1987 ROD. The air
stripping towers will be equipped with air
emission controls in order, among other
purposes, to meet Maricopa County require-
ments, including Rule 32-C and. any other
applicable provisions of the Arizona imple-
mentation plan under the Clean Air Act. If
the Maricopa County requirements are revised
and approved by EPA pursuant to the Clean Air
Act to specify thaf sources such as the air
stripping towers are not subject to air
emission controls, then Goodyear may petition
EPA to agree to amend this consent decree to
remove the air emission control requirement
of this paragraph. Ar.y dispute with regard
-------
Assistant Attorney General
October 19, 1988
Page 5
to any such petition shall be subject to
dispute resolution in accordance with
paragraph XXII.
Goodyear entered into negotiations with EPA and DOJ
concerning the proposed consent decree guided by two principal
documents: the provisions of CERCLA/SARA, including related
guidance documents and the National Contingency Plan; and the
requirements of the ROD.
1. ROD Requirements;
The ROD specifies that "the air stripping towers
;related to the air stripping required to . reduce the VOC
contamination of the groundwater) will be equipped with air
emission controls in order to meet Maricopa County requirements
that all new air emissions sources employ reasonably achievable
control technology to reduce emissions, as promulgated by the
Superfund Amendment and Reauthorization Act (SARA). Remedies
should significantly and permanently reduce the volume, toxicity
and mobility of the contaminants."
During recent discussions with EPA, concerns have sur-
faced as to precisely what the requirements of the ROD are ar.c
whether or not the above-quoted provision in the proposed consent
decree adequately reflects those requirements." Specifically,
Goodyear was operating under the impression that Maricopa County
Air " Pollution Control ("MCAPC"), Rules and Regulations,
Regulation III, Rule 32(C) requires application of emission
control technology for new VOC emission sources under certain
conditions. Through its consultant, Dr. Lial F. Tischler of
Engineering-Science, Inc., Goodyear advised EPA by letter dated
October 2, 1987, (after the date of the ROD and the notice
letter) that it had conferred with Mr. Lawrence Crisafulli of the
Maricopa County Air Pollution Control to determine how these
regulations apply to VOC stripping columns used for groundwater
treatment. That conference revealed that the primary condition
that the MCAPC applies to determine if emission controls are
required for a new source is a minimum emission rate of 40 pounds
of VOC emissions per day. At an estimated maximum rate of 10
pounds of VOC emissions per day, the air stripping requirements
for the Litchfield site are well below the de minimis level ar.c
should not require emission controls. A copy of this letter .5
included as Attachment 1.
Goodyear also has requested an opinion from Ar::c-.3
counsel, Fer.r.emore Craig, concerning the requirements fcr a.r
strippir.g under the Arizona law and related implementation plar..
-------
Assistant Attorney General
October L9, 1988
Page 5
We are attaching to this letter a copy of that memorandum dated
October 10, 1988, (Attachment 2) that basically concludes that
Rule 32(C)., which has now been renumbered as Rule 320." as a result
..of amendments to the Mariccpa County Air Pollution-Control Rules
.and Regulations on July 15, 1988, does not require carbon
adsorption emission controls for the air stripping- towers.
When Goodyear was involved in negotiating the proposed
consent decree with EPA and DOJ, it was operating under the
understanding that the limit in Maricopa County for the discharge
of VOC contaminants from air stripping towers without carbon
absorption is 40 pounds per day. It also was aware that there
were considerable discussions between EPA and the state of
Arizona, concerning the amendment of the state's implementation
plan, and that these requirements could be adjus-ted upward or
downward. Although Goodyear had not yet retained a consultant to
commence the conceptual design for this project or receive the
benefit of the consultant's advice in this area, Goodyear
nevertheless supported the language in Paragraph VII of 'the
consent decree in order to recognize the opportunity to adjust
the design, construction and operation of the OU if changes in
the Arizona/Maricopa County requirements were to occur. As
indicated by the Fennemore. Craig memorandum, changes did occur on
July 15, 1988, but these changes did not alter the general
statement within the regulations that up to 40 pounds per day of
VOC emissions are acceptable without carbon adsorption emission
controls.
2. CZRCLA/SARA Requirements;
Remedial action selected under SARA must attain a
degree of cleanup of hazardous substances, pollutants or
contaminants which include applicable, relevant and appropriate
federal and state requirements (often referred to as "AAARS").
"Compliance [with these requirements] is required at the
completion of the remedial action for hazardous substances,
pollutants or contaminants that remain on site."1- Thus, EPA's
guidance emphasizes that these requirements must be achieved in
the context of the final remedy, but not necessarily in the
context of the interim remedy such as the OU envisioned for this
site.
Further emphasis of this point exists in Sectior.
121(d)(4) which specifies that EPA:
52 Fed. Reg., page 32495, "Super fund Program; Interim Guidance
on Compliance with Applicable or Relevant and Appropriate
Requirements; Notice of Guidance, August 27, 1987."'
-------
Assistant Attorney General
October 19, 1988
Page 7
. . . may select a remedial action meeting the
requirements of paragraph (1) [i.e., ARARS]
that does not attain a level or. standard of
;." " control at least equivalent t6~~a_ legally '
" ; applicable or relevant and •;appropriate '
standard, requirement, criteria, or-limitation • ;
as required by paragraph (2) if [EPA] finds •
that -
(A) The remedial action selected is
only part of a total remedial action that will
attain such level or standard of control when
completed; . . .
While" CToodyear has been unable to obtain any "official"
interpretation by EPA of the criteria that it will consider with
respect to this waiver, we have examined a. recent draft guidance
document entitled "CERCLA Compliance With Other Laws Manual"
dated August 8, 1988 (OSWER Directive 9234.1-01). Paragraph 1.3
of that document, entitled CERCLA Waiver Criteria for ARARS,
states as follows:
This waiver may be applicable to interim
measures that are expected to be followed
within a reasonable time by complete measures
that will attain ARARS. The interim measures
waiver may apply to sites at which a final
site remedy is divided into several smaller
actions.
* * *
The factors that may be appropriate for
invoking this waiver include:
• Non-interference with final remedy. The
interim measures selected must not
interfere with, preclude, or delay the
final remedy, consistent with EPA's
priorities for taking further action.
(Emphasis added) .
Goodyear believes that this guidance is "relevar
the situation at hand. Specifically, in a reasonable peri
time, Gcodyear anticipates that EPA will complete the feasi
study fcr the final remedy at this site and issue a ROD tr.a
-------
Assistant Attorney General
October 19, 1988
Page 8
inter alia, address the need for additional groundwater treatment
and perhaps other related matters. Goodyear also believes chat
it should not embark on costly requirements to design an air
stripper with carbon adsorption features if those features become
redundant, or are inconsistent with the overall requirements, of
the final remedy. Thus, Goodyear maintains chat the. consent
decree should be adjusted to clarify that air stripping towers do
not have to be equipped with carbon adsorption devices for chis
interim remedy measure. As indicated in the Fennemore Craig
memorandum, we have received concurrence with this approach from
the Maricopa County officials (Attachment 3).
Section 121(b) of SARA requires EPA, in assessing
alternative remedial actions, to take into account a number of
criteria.which include:
(1) the persistence, toxicity, and mobility of the
hazardous substances;
(2) long term maintenance costs;
(3) the cost effectiveness of the remedy; and
(4) the ability of the remedy to adequately protect
human health and the environment.
It could be argued that regardless of state
requirements, carbon adsorption should be a requirement of this
OU because it would serve' to reduce the mobility of hazardous
substances into the environment. However, SARA offers other
criteria that also must be considered, including long term
maintenance costs and cost effectiveness. In this regard,
Goodyear estimates that the capital cost for the installation c:
carbon adsorption units could range from $200,000 to 5900,000 Lr.
capital costs (depending on whether an onsite carbon reger.eratic-
system is included). Thereafter, annual operation and main-
tenance costs could range from 5100,000 to $200,000. Goccyea:
believes that such an approach, based on the interpretation c:
the proposed consent decree, would not meet the SARA "ccst
effective criteria" as the "effectiveness" criteria piucticed by
£?A in the administration of the Superfund program is based c.-. a
risk range of 10-4 to 10-7. Simply stated, we now know thr-ug-
the conceptual design that the TCE air emissions will not excee-
this range regardless of whether air stripping with or witr.c--.
carbon r. ;~orption is used. Thus, carbon adsorption simply is ---.
cost efzs:tive.
As the August 8, 1988 "CERCLA Compliance With C-..--?:
-------
Assistant Attorney General
October 19, 1988
Page 9
Laws Manual" indicates, ARARS fall into three basic categories:
(1) ambient or chemical specific requirements; (2) performance,
design or other action specific requirements; and (3) location
specific requirements. (Goodyear does not believe that this
third category has any relevance to these discussions.) While
this, document and the August 27, 1987 EPA interim guidance
indicate that a national ambient air quality standard is a type
of chemical - specific ARAR, there are no such standards for TCZ.
Using the risk range of 10-4 to 10-7 as presented in the
"Guidance on Feasibility Studies Under CERCLA" dated April, 1985,
p. V-19 and in the "Superfund Public Health Evaluation Manual"
dated October, 1986 (OSWER Directive 9285.4-1, pp. 91-93, section
8.32) as a guide, Goodyear has preliminarily concluded that,
under the most conservative of circumstances,2 the health risk of
exposure to the air emissions from the air strippers, without
carbon adsorption, is no worse than 10-4. Goodyear is developing
additional data to support this position, which we will forward
under separate cover. This will further verify our p-sition that
there will not be an unacceptable risk -to public health if these
contaminants are released into the environment in these de
minimis quantities.
The second category of ARARS - "performance, design or
other action specific requirements" - could arguably include
carbon adsorption, if this requirement is viewed in a vacuum.
However, as we have discussed above, this requirement must be
viewed in light of other SARA requirements of cost effectiveness
and adequate protection of public health. We believe that both
of these requirements are met without carbon adsorption. In
addition, assuming arguendo that these standards still apply, the
waiver of such standards for an interim remedy also seems
appropriate.
Accordingly, Goodyear proposes that subparagraph 5(c)
of Paragraph VII of the consent decree be modified as fellows:
Air stripping will be used to reduce volatile
organic compound ("VOC") contamination to meet
federal and state standards. At the present
time, relevant state implementation plan and
Maricopa County requirements do not require
sources of VOC emissions that are well below
40 pounds per day, such as the air stripping
towers, to utilize carbon adsorption emission
2 The assumptions made include an emissions rate of 10 pcur.ds
per day for 70 years, continuous worst case metecrolccical
conditions, and continuous exocsure on a 24 hour basis.
-------
Assistant Attorney General
October 19, 1988
Page 10
controls. If the applicable requirements are
revised to specify that sources such as the
air stripping towers are subject to air-
emission control, then the provisions on -
modification in Paragraph XXV apply. Any--.
dispute with regard to such emission controls----
shall be subject to dispute resolution in
accordance with Paragraph XXII.
In summary, Goodyear has maintained its commitment to
address the problems at the Litchfield site in a manner that will
adequately protect public health and the environment. As it
pursues this commitment, Goodyear anticipates that new facts will
always emerge. The comments that we submit on thi-s proposed
consent decree today relate to refinements to the approach to be
taken on the OU based on a better appreciation of the facts that
we now have, and the applicability of CERCLA/SARA and related
guidance documents to those facts.
Sincerely yours,
Takashi Ito
Attorney
TI:afj
Attachments
cc: Daniel W. McGovern, Regional Administrator, EPA
Jeff Rosenbloom, EPA
Hugh Barroll, EPA
Barry Sandals, DOJ
-------
2901
AuS
ENGINEERING-SCIENCE, INC.
October 2, 1987
Mr. Jeff Rosenbloom (7-4-2) :.:..-
Remedial Project Manager
U.S. Environmental Protection Agency
Region DC
215 Fremont Street
San Francisco, California 94105
Re: Air Emission Controls on PGA Operable Unit . . -
Dear Mr. Rosenbloom: '. • ; •
We received your letter of August 18, 1987 responding to our submission of the
air quality modeling of the emissions from the volatile organic compound (VQC)
stripping columns for the operable unit (OU) at the Phoenix-Goodyear Airport
(PGA). As you acknowledged in your letter, the air quality modeling demonstrates
that the uncontrolled emissions of trichloroethylene (7CE) from the stripper result in
ambient concentrations well below the 0.769 jig/m3 annual average which Table 9-6
of the Public Comment Feasibility Study for Section 16 Operable Unit, June 1987,
cites as the lower cutoff limit for requiring air emission controls. In addition,
modeling we performed for our comments on the above document demonstrates that
maximum 24-hour concentrations of 7CE are always less than 1 percent of the
short-term exposure limit adopted by the American Conference of Governmental
Hygienists. It is clear that the uncontrolled emissions of 7CE from the shipping
columns will not jeopardize human health or the environment.
In your letter you cite rwo bases for a policy decision that air emissions controls
will be required on the VQC stripping columns: (1) the wording in Section
121(b)(l) of the. Superfund Amendments and Reauthorization Act (SARA); and (2)
Maricopa County Air Pollution Control Rules and Regulations, Regulation 2, Rule
32(c). We do not believe that the Agency is interpreting either of these rules
correctly for this situation.
Section 121(b)(l) of SARA, as you state, indicates that preference should be
given to remedial actions which wi// result in permanent and significant decreases in
toxiciry, mobility, or volume of hazardous substances. As you correctly point out,
the mobility of the VOCs in the ground water is increased by air stripping.
However, the statement that the volume of the contaminants is increased is incorrect
• although the volume of the media in which the hazardous substance is distributed is
increased substantially, the mass of VOCs emitted is constant and in fact is
-------
Mr. Jeff Rosenbloom
Page 2
October!, 1987
substantially diluted in concentration. This dilution and increased mobility, in cum,
decrease the potential exposure rate for any individual as compared to tne ground
;tcr exposure potential, as demonstrated by the air quality modeling. It can be
i'-ued that although the TCE is unaffected by the transport from the water to the air
in the stripper, the overall toxicity is reduced because of the substantial dilution
which occurs in going from the water to the air.
As you have also acknowledged in the August 18th letter, Section 121(b)(l) of
SARA also has expiicit limitations on deciding whether a particular remedy is
needed. With respect to iong-ierm and short-term potential health effects (Section
121(b)(l)(D), we have already shown, and you have acknowledged, that the
uncontrolled TCE emissions (by far the most significant air pollutant) from the
stripping column pose no long-term and short-term health effects. . Section
121(b)(l)(E) requires an assessment of long-term maintenance costs. The costs
associated with removing the estimated 7 pounds per day of TCE from the VQC
stripping column off-gas cannot meet any reasonable cost effectiveness test, as
shown below.
As we documented in our comments on the OU public comment document,
about 7 pounds per day of TCE will be emitted from the stripping columns. Other
VOCs will amount to a total of not more than 3 pounds per day. For the purposes of
this analysis, we assume that a total of 10 pounds per day of total VOCs will be
emitted by the columns. Using a carbon loading of 0.1 pound of VQC per pound of
carbon, 36,000 pounds per year of carbon will be required. At S2 per pound for
replacement (includes custom regeneration), the annual operating cost'is S72.000 for
the air emissions control unit excluding the maintenance costs and capital costs for
this equipment. This works out as a cos: of 343,000 per metric*ton of VQC
removed for the carbon replacement alone. In its proposed rule for regulation of
benzene under Section 112 of the Clean Air Act, the E?A's Air Office used a cos;
effectiveness value of S1050 per metric ton of VQC reduction to establish a size
cutoff for facilities covered by the emission standards (Benzene Fugitive Emission •
Background Information for Promulgated Standards, EPA 450/3-8Q-032b, June
1982). EPA determined thai controls at this level are not cost-effective for benzene,
2 carcinogenic air pollutant. In addition, EPA selected a c?st-effecdveness limit for
VQCs of SI600 per metric ton in setting guidance for 36 major organic chemicals
(Guideline Series (Draft) Control of Volatile Organic Compound Emissions from Air
Oxidation Processes in Synthetic Organic Chemical Manufacturing Industry, CTG,
Office of Air Quality Planning and Standards, March 1984).
The cost of the air emissions controls for the PGA VOC stripping columns is
more than an order of magnitude greater --.an the cost-effectiveness limits used by
the Agency to evaluate air pollution controls for hazar-oua air pollutants and VOCs.
We do not believe that SARA intends that control technologies which are so
inefficient are to be mandated - that is, in our opinion, the reason that Sections
121(b)(l)(D) and (E) are included in SARA. We do not believe that -Jiis basis for
EPA's requirement for emissions controls on the strippers is justified.
-------
Mr. Jeff Rosenbloom
Page 3
October 2, 1987
(RACT) for new \'OC emissions sources under certain conditions. We spoke
Mr. Larry Crissafulli of Maricopa County Air Pollution Control (MCAPC) to
determine how they apply this regulation to VQC stripping columns used for ground
water treatment. The pnnary condition that MCAPC applies to determine-if RACT
is required for a new source is a minimum emissions rate of 40 pounds per day. At
an estimated rate of 10 pounds of VQC emissions per day, the PGA air stripping
columns are well below the de minimis level and should not require-emissions
controls. Mr. Crissafulli indicated to us that there are 5 to 6 stripping columns
currently operating in Maricopa County and none of these have air emissions
controls. One of these stripping columns is a large (32 foot high, 13 foot diameter)
unit which strips TCE from a drinking water supply well in Scottsdaie. The other
columns all strip gasoline-contaminated groundwater which would contain benzene,
toluene, and xyienes as well as other YOCs.
It is obvious that MCAPC does not interpret their regulation to require air
emissions controls on de minimis VQC sources. This means that EPA's second
basis for insisting on air emissions controls is also unjustified.
W- respectfully request that the Agency reconsider the policy decision to require
air emissions controls on the air stripping columns. Aside from the costs," we
believe that the additional maintenance and operational requirements for the air
emissions control device will be a very substantial addition to the operable unit.
Since we will be routinely sampling the off-gas from the stripping columns, we will
be able to verify that air emissions do not represent a hazard to human health and the
environment. It emissions are greater than estimated, an air emissions concrol unit
car, be retrofit to the columns.
If you have any questions about our analysis and comments, please feel free to
call me or Annette Ponds. We would look to further discussion of this issue during
the Consent Decree negotiations.
Sincerelv,
al F. Tischler, Ph.D., P.Z.
xc: T. Ito, Goodyear
J. Smergiia, Goodyear
A. Pones, ES
-------
FEHNEMORE CRAIG
Memorandum
To: Goodyear - PGA File
Ff0fB: Fennemore Craig
°"t: October 10, 1988
"*: Reasons Why Goodyear Should Not Be Required To Install A Control
Device On Its Air Stripper Pursuant to Maricopa County Rule 32(C)
The Consent Decree
The Consent Decree for the PGA site provides in pertinent part as
follows:
Air stripping will be used to reduce volatile organic
compound ("VOC") contamination to meet federal and state
standards as prescribed in Table I of the 1987 ROD. The
air stripping towers will be equipped with air emission
controls in order, among other purposes, to meet Maricoca
County requirements, including Rule 32-C and any other
applicable provisions of the Arizona Implementation Plan
under the Clean Air Act. If the Maricopa County
requirements are revised and approved by EPA pursuant to
the Clean Air Act to specify that sources such as the air
stripping towers are not subject to air emission controls,
then Goodyear may petition EPA to agree to amend this
Consent Decree to remove the air emission control
requirement of this Paragraph. Any dispute with regard to
any such petition shall be subject to dispute resolution in
accordance with Paragraph XXII. [Emphasis added.]
The Applicable Regulations
The Maricopa County Air Pollution Control Rules and Regulations,
prior to July 15, 1988, provided in pertinent part as follows:
Rule 32. Odors and Gaseous Emissions
C. Materials including, but not limited to, solvents or
other volatile csmoounds. paints, acids, alkalies,
pesticides, fertilizer and manure shall be processed.
stored, used and transported in such a manner and by
such means "hat they will not unreasonably evaporate.
leak, escape or be otherwise discharged into the
ambient air so as to cause or contribute to air
pollution; and where means are available to reduce
effectively the contribution to air pollution from
-------
evaporation, leakage or discharge, the installation
and use of such control methods, devices or equipment
shall be mandatory. [Emphasis added.]
Rule 34. Organic Solvents
E. Except as provided in paragraph C.2 (governing dry
cleaning establishments], no person shall discharge
more than 15 pounds of organic materials into the
atmosphere in any one (I) day from any machine,
equipment, incinerator, device, or other article in
which any organic solvent or any material containing
organic solvent comes into contact with flame or is
baked, heat-cured, or heat-polymerized, in the
presence of oxygen.
F. No aerson shall discharge more than 40 pounds of
organic material into the atmosphere in anv one d]
<3a.v from anv machine, •equipment, incinerator. Device
or other article used under conditions other than
described in paragraph E of this rule for employing.
applying, evaporating or drying anv photochemical!v
reactive solvent as defined in paragraph I of this
rule.
G. Emission of organic materials into the atmosphere
required to be controlled bv paragraphs E and £ of
this rule shal1 be reduced by;
L. Incineration, provided that ninety percent (90%)
or more of the carbon in the organic material being
incinerated is oxidized to carbon dioxide, or
2. Adsorption, or
3. Processing in a manner not less effective than in
Subsection G.I. or G.2. above.
H. The provisions of this rule shall not apply to:
1. The manufacturer of organic solvents, or the
transport or storage of oraanic solvents or materials
containing organic solvents.
2. The use of equipment for which other requirements
are specified by Rule 33 'storage and handling of
petroleum products).
3. The spraying or other employment of insecticides,
pesticides or herbicides.
I. For the purposes of this rule, a photochemically
reactive solvent is a sol'/sr,;. with an aggregate of
more than twenty percent (20X) of its total volume
composed of the chemical compounds classified below or
which exceeds any of the following individual
percentage composition limitations, referred to the
total volume of solvent:
1. A combination of hydrocarbons, alcohols,
aldehydes, esters, ethers, or ketones having an
-2-
-------
olefinic or cydo-olefinic type of unsaturation: five
percent (5X);
2. A combination of aromatic compounds with eight
(8) or more carbon atoms to the molecule except
ethylbenzene: eight percent (8%);
3. A combination of ethylbenzene, ketones having
branched hydrocarbon structures, trichloroethylene or
toluene: twenty percent (20X).
Whenever any organic solvent or any constituent of an
organic solvent may be classified from its chemical
structure into more than one of the above groups or
organic compounds, it shall be considered as a member
of the most reactive chemical group, that is, that
group having the least allowable percent of the total
volume of solvents. [Emphasis added.]
On or about July 15, 1988, the Maricopa County Board of Supervisors
adopted a revised version of the Maricopa County Air Pollution Control
Regulations. (These regulations are developed by the Maricopa County
Department of Health Services, Bureau of Air Pollution Control, but it is the
Maricooa County Board of Supervisors that votes to adopt the regulations as
law.) Regulation III, Rule 320, Section 300 now provides the standards for the
emission of odorous and gaseous air contaminants. In pertinent part, Rule 320
(replacing Rule 32-C) provides:
SECTION 101 PURPOSE: To limit the emission of odorous and
other gaseous air contaminants into the atmosphere.
SECTION 300 - STANDARDS: No person shall omit gaseous or
odorous air contaminants from equipment, operations or
premises under his control in such quantifies or concentra-
tions as to cause air pollution.
SECTION 302 MATERIALS CONTAINMENT; Materials including.
but not limited to, solvents or other volatile compounds.
paints, acids, alkalies, pesticides, fertilizer and manure
shall be processed, stored, used and transported in such a
manner and bv such means that they will not unreasonably
evaporate, leak, escape or be otherwise discharged into the
ambient air so as to cause or contribute to air pollution.
Where means are available to reduce effectively the
contribution to air pollution from evaporation, leakage or
discharge, the installation and use of such control
methods, devices or equipment shall be mandatory.
(Emphasis added.j
-3-
-------
Regulation III, Rule 330, Section 300 now provides the standards for
the discharge of volatile organic compounds ("VOCs"). In pertinent part, this
regulation (replacing Rule 34) provides:
SECTION 301 LIMITATIONS - OPERATIONS INVOLVING HEAT: No
person shall discharge more than 15 pounds (6.3 kg) of
volatile organic compounds into the atmosphere in any one
day from any machine, equipment, device or other article in
which any organic solvent or any material containing
organic solvent comes into contact with flame or is
evaporated at temperatures exceeding 200 degrees F (93.3
degrees C) in the presence of oxygen, unless such discharge
has been reduced by at least 85 percent.
SECTION 302 LIMITATIONS - NON-COMPLYING SOLVENTS: N&
persons shall discharge more than 4Q sounds (18 kg) of
volatile organic compounds Into the atmosoners in anv one
day from any machine, equipment, device or other article
used under conditions other than described in Section 301
of this Rule for employing, applying, evaporating or drying
any non-ccmplying solvent as defined in Section 201 of this
Rule, or material containing such non-complying solvent,
unless its discharge has been -educed bv at least 35
percent.
SECTION 305 REDUCTIONS REQUIRED: Emission of organic
materials into the atmosphere required to be controlled by
Section 301 or 302 of this Rule shall be reduced bv:
305.1 Incineration, provided that 90 percent or more
of the carbon in the organic material being incinerated is
oxidized to carbon dioxide, or
305.2 Adsorption, or
305.3 Processing in a manner not less effective than
in Subsection above 305.1 or 305.2 of this Rule. [Emphasis
added.]
s Position ~-- —
The proposed PGA air stripping tower will not release more than 1C
pounds of TCE emissions per day, and will emit at that level for only a
relatively short time. During most of twenty year operating period, emissions
will be around 2.5 pounds per day. See Exhibit A attached hereto.
The EPA contends that Rule 32(C), a general regulation relating ::
odors and gaseous air contaminants, applies to the air stripper at the PGA -,•-.•?
and imposes a separate mandatory requirement for carbon adsorption enrss ;-
-4-
-------
controls. The EPA contends that Rule 32(C) (now Section 302 in Rule 320)
requires Goodyear to install expensive carbon adsorption emission controls for
volatile organic compounds even where such carbon adsorption otherwise would
not be required under Rule 34(F) (now Section 302 of Rule 330), the rule
specifically addressing VOCs. Rule 34(F) (now Rule 330) establishes a
threshold VOC emission level of 40 pounds per day before carbon adsorption
controls will be required.
ARGUMENT
1. Even if Rule 12(C] fnow Rule 320^ did apply, the EPA should defe"
to Maricooa County's interpretation that this Maricooa County regulation does
not require carbon adsorption for the'air stripping tower. - • •
Maricopa County's Bureau of Air Pollution Control" has reviewed the.
data concerning expected emissions from the air stripping tower and it has
determined that carbon adsorption control devices are not required at the PGA
site. In a letter dated October 3, 19881, Lawrence M. Crisafulli, a Public
Health Engineer of the Maricopa County Bureau of Air Pollution Control, stated
that, based on his examination of the probable emission of VOCs from the
planned air stripper, the Bureau has concluded Goodyear is not required to
install carbon adsorption control devices pursuant to Rule 320 [the present
version of Rule 32(C)] or any other applicable regulation. This conclusion
rests on the Bureau's interpretation of Rule 32(C) (now Rule 320), a regulation
that was developed by the Bureau itself. So long as Goodyear complies with a
few unrelated permit conditions, Maricopa County's Bureau of Air Pollution
Control will allow air stripping to proceed without any carbon adsorption
emission controls.
The EPA should defer to the interpretation of the Maricopa County
Bureau of Air Pollution Control. The Bureau wrote the regulation at issue
A copy of that letter is attached as Exhibit B. Exhibit B refers to another
letter dated September 29, 1988, which is attached as Exhibit C hereto.
-5-
-------
(Rule 32(C)) in the first place and can better discern the intent of its own
rules. The Bureau clearly has decided Rule 32(C) (now Rule 320) does not
require carbon adsorption emission controls in the PGA air stripper.
In interpreting an administrative regulation, great deference is
given the appropriate agency's understanding of that regulation. If the agency
is interpreting regulations it drafted itself, deference is even more clearly
called for. Sierra Pacific °ower Company v. United States Environmental
Protection Aoencv. 647 F.2d 60, 65 (9th Cir. 1981). An agency's interpretation
of its own- rule is normally given controlling weight unless it is plainly
erroneous. Tele-Media Corn, v. FCC/ 697 F.2d 402 (D.C. Cir. 1983) (citing
Udall v. Tallman. 380 U.S. 1 1965) ); ig£ also Sainberg v. Morton. 363 F.
Supp. 12S9 (D. Ariz. 1973) (Secretary of Interior's construction of own
agency's regulation controlling unless plainly erroneous or inconsistent with
the regulation itself). If the agency's interpretation is merely one among
several reasonable alternatives, it should stand even if another interpretation
wight appear more reasonable. Allen M. Campbell Construction Company General
Contractors. Inc. v. Llovd Wood Construction Company. 446 F.2d 261 (5th Cir.
1971).
The EPA frequently requests a court or other agency to defer to EPA's
interpretation of any EPA regulation. E?A similarly should defer to Maricopa
County's interpretation of a Maricopa County regulation. No carbon adsorption
controls are required.
2. The EPA's interpretation of Rule 32fCK part of a general
regulation on odorous and gaspoiie contaminants, is so broad it would render
other, -norg specific regulations directly "glating to carbon adsorption of vQCs
superfluous and without meaning.
Rule 32(C) (now Rule 320) is a very broad and general section
addressing "material containment" of a variety of odorous and gaseous
materials. It does not require specific levels of emission reduction nor does
-6-
-------
it specify a particular type of technology M.e.. carbon adsorption) to be
employed in controlling emissions. The regulation on odorous and gaseous
contaminants generally forbids any "unreasonable" discharge of "materials",
including VOCs, into the air. It then provides that if means ("containment")
are available to reduce any such "unreasonable" contribution to air pollution,
the use of these means shall be "mandatory."
Maricopa County's Bureau of Air Pollution Control has already
determined that the anticipated discharges of VOCs from the air stripper (less
than 10 pounds per day) are not "unreasonable" and therefore do not require
emission controls such as carbon adsorption. Furthermore, Rule 34(F) (now Rule
330) sets a threshold of 40 pounds per day before carbon adsorption emission
controls will be required, clearly indicating that daily discharges that are
well below that amount M.e.. 10 pounds) would be considered "reasonable" in
the absence of carbon adsorption.
Under EPA's interpretation of Rule 32(C) (now Rule 320), however, any
facility that releases VOCs into the air, even if well under the 40 pound limit
set by Rule 32(C), must install carbon adsorption control devices to recucs
even a de Tiinimis level of air emissions whenever carbon adsorption would be
"effective." Such a reading of the general regulation on odorous and gaseous
air contaminants would render the specific 40 pound emission threshold
(Maricopa County's judgment of the appropriate level at which to require carbon
adsorption) completely superfluous. EPA's interpretation also distorts the
intent of Rule 32(C) (now Rule 320), which was to permit Maricopa County to
require simple "containment" measures to reduce emissions from VOCs,
pesticides, fertilizer, manure, and the like, not to require carbon
adsorption.2
Lawrence Crisafulli of the Bureau of Air Pollution Control explained that
Rule 32(C)'s (now Rule 320's) general purpose is to ensure that simple and
-7-
-------
The particular 40 pound limit of Rule 34(F) (now Rule 330) was
carefully arrived at. It represents Maric:pa County's assessment of discharge
levels of VOCs which are "reasonable" in the absence of carbon adsorption.
EPA's reading of Rule 32(C) to require every single "feasible" reduction of VOC
emissions would make the 40 pound "carbon adsorption" threshold in the VOC
regulation (Rule 34(F), now Rule 330) a complete nullity. If EPA were correct
in its interpretation, every emission below 40 pounds per day of VOCs would
have to have carbon adsorption controls (regardless of cost) if carbon
adsorption would be "effective." If this were "true, there would be no need for
the 40 pound threshold in Rule 34(F) (now Rule 330).
Maricopa County's interpretation of its own regulations is consistent
with generally accepted principles of statutory and regulatory construction.3
"Fundamental maxims of statutory construction require that a specific statutory
section qualifies a more general section and will govern, even though the
general provisions, standing alone, would encompass the same subject."
Trustees of Amalgamated Insurance Fund v. Gelfrnan Industries. Inc.. 784 F.2d
926, 930 (9th Cir.), cart, denied. 107 S. Ct. 90 (1986). Accard Union Centra:
Life Insurance Company v. Wemick. 777 F.2d 499 (9th Cir. 1985) (refusing to
read one section so as to render another superfluous); Pima County v. Heinfgid.
134 Ariz. 133, 654 P.2d 281 (1982) fen bane) (if two statutes deal with the
same subject, more specific statute controls); Whitfield Transportation v.
Brooks. 81 Ariz. i:6, 141, 302 P.2d 526, 529 (195.6) (if "there are two
provisions applicable to the same subject, one general in its scope and the
comcaratively inexpensive means of reducing emissions (hence the tife
"material containment") are implemented even where expected emissions are belcw
40 pounds per day.
3 Those same principles of construction that apply to statutes apply with' equa'
force to rules and regulations promulgated by administrative bodies. Mar'ar •/.
State. 136 Ariz. 404, 410, 666 P.2d 504, 510 (App. 1983).
-a-
-------
other covering a limited portion only of the subject included in the general
one, the special statute is to be considered as governing the exception")
(citation omitted).
The authorities cited above reiterate the logical proposition that a
general regulation should not override a more specific regulation with which it
is inconsistent. Therefore, Rule 34(F) (now Rule 330), the specific regulation
on when to require carbon adsorption for VOC emissions, must govern with
respect to the issue of carbon adsorption emission controls at the PGA site.
No carbon adsorption controls are required because VOC emissions will be well
below the 40 pounds per day thresho>d. Rule 32(C) (now Rule 320) does not
govern because it is a less specific regulation and therefore cannot override
Rule 34(F) (now Rule 330) on the issue of carbon adsorption.
3. Even if Rule 32fH (now Rule 320) did apply to Goodvear's tower.
the requirement of carbon adsorption control devices would be unreasonable
within the meaning of the Rule.
Rule 32(C) requires only that the processing, storing, use or
transportation of VOCs be "in such a manner and by such means that they will
not unreasonably evaporate, leak, escape or be otherwise discharged"; and chat
where such "unreasonable" emissions otherwise would result, control methods
shall be mandatory. This second clause in Rule 32(C) mandating control methods
applies where means are available to "reduce effectively" any contribution to
air pollution. The EPA's interpretation is based on reading this second clause
in a "vacuum/ standing completely by itself. This clause, however, also must
be read in conjunction with the preceding clause in Rule 32(C) and its explicit
reference to reasonableness.4 Virtually any activity that contributes to air
pollution can be further reduced, if enough money is committed to the effort.
4 As already discussed above, the clause in Rule 32(C) (now Rule 320) must
also be read in conjunction with Rule 34(F) (now Rule 330). When read in
conjunction with Rule 34(F), it is clear that carbon adsorption is not requires
unless VOC emissions are 40 pounds per day.
-9-
-------
Rule 32(C] only mandates centrals in the second clause If the emissions are
initially determined to be "unreasonable" pursuant ta thq first clause cf ?ule
22(C}.
Goodyear's proposed tower will not result in any such unreasonable
discharges for two reasons. First, as already noted, the discharges are well
under the "reasonable" threshold of 40 pounds provided for in the rule
specifically addressing control of VOCs by carbon adsorption (Rule 34(F), now
Rule 330); by the definition of Maricopa County, these discharges are thus
reasonable in the absence of carbon adsorption controls. Second, the very
concept of reasonableness implies a* balancing of costs and benefits. The
benefits of reducing VOC emissions below these already low levels are minimal;
no significant health or environmental gain would be realized. The costs of
carbon adsorption, on the other hand, are significant. Installation of a
carbon adsorption unit is estimated at between $350,000 and 5500,000.
Operating costs would increase by approximately Sfl8,000 per year, or $1,760,000
over a projected 20 year project life. Measured against the minimal good
achieved by carbon adsorption in this case, such an expenditure appears
exorbitant and unwarranted.
According to Mr. Lawrence Crisafulli, a balancing of costs and
benefits is absolutely essential prior to any determination that carbon
adsorption should be mandated pursuant to Rule 32(C) (now Rule 320),
particularly since carbon adsorption was not the intended thrust of Rule 32(C).
At present, preliminary cost evaluations indicate a carbon adsorption unit
installation cost for the PGA air stripper would range from $350,000 to
$500,000. In addition, operating costs are projected to increase from 16$ per
1,000 gallons of water treated to 30
-------
the projected flow rate of 1,200 gpm, the air stripper operating cost would
increase from S100,900/year to S189,000/year. &* Exhibit C.
If operating costs are considered alone, the cost of VOC air
emissions controls is approximately $98,000 per ton of VOC removal. [d. in
light of this cost data, it was the Maricooa County Bureau of Air Pollution
Control's unequivocal opinion that Rule 32(H [now Rule 3201 does not reouirg
carbon adsorption emission controls for an air stripper unit with emission
levels such as those anticipated for the PGA site. See Exhibit B.
• Under Rule 32(C) (now Rule 320), it is Maricopa County's Bureau of
Air Pollution Control that should decide if the additional benefits of carbon
adsorption control methods in a situation involving VOC emission levels below
40 pounds per day are outweighed by the excessive additional costs of achieving
further pollution reduction. By promulgating Rule 34(F) (now Rule 330), which
explicitly states that emission level for VOCs below 40 pounds per day
typically will not result in carbon adsorption controls, and by ruling that no
further control device is necessary on the proposed air stripping tower at the
PGA site, Maricopa County has concluded that the minimal benefits of carbon
adsorption emission controls at the PGA site are easily outweighed by the
prohibitive costs. The EPA should defer to the Maricopa County Bureau of Air
Pollution Control when it comes to determining whether levels of VOC emissions
in this situation would be "unreasonable" in the absence of carbon adsorption
pursuant to Rule 32(C).
4. Rule 32(C] fnow Rule 320) does not apply at all to Goodvear's
proposed air stripping tower because Goodvear is not processing, storing, us^nq
or transporting the VOCs.
The EPA has focused only on the second clause of the sentence that
comprised Rule 32(C), which stated as follows: y
"and where means are available to reduce effectively the
contribution to air pollution from evaporation, leakage or
-11-
-------
discharge, the installation and use of such control
methods, devices or equipment shall be mandatory."
The initial portion of Rule 32(C), however, makes it clear that it should apply
only to regulated materials that are "jrocsssed. stored, used and
transported." (The same language now exists in Rule 320, which replaced Rule
32(C) after July IS, 1988.) The thrust of the regulation is to require
"containment" of materials that are being "processed, stored, used or
transported," words that imply a commercial context.
The TCE at the PGA site will not be stored, used, or transported, nor
will it be processed within the meaning of Rule 32(C) (now Rule 320). The term
*
"process" connotes treating raw materials, chemically or physically, in
preparation for introduction into the marketplace. ig£, e.g.. Employment
Security Commission of Arizona v. Brown. L09 Ariz. 183,- 507 P.2d 108 (1973) (en
bane) (vacuum cooling plant employees involved in "processing" lettuce because
cooling the lettuce helps prepare it for market); Krienke v. Southwestern
Superior Products Corporation. 376 S.W.2d 936 (Tex. Civ. App. 1964) (citing
with approval a definition of "process" based on subjecting raw materials to
manufacture, development, and preparation for the market). Given the fact that
"process" applies generally in the context of commercial use (consistent with
the general commercial context of the juxtaposed terms "stored, used or
transported"), Goodyear's emissions of VOCs from an air stripping tower should
not be considered "processing" of those VOCs within the meaning of Rule 32(C)
(now Rule 320).
Rule 32(C) (now Rule 320) should not apply to the air stripping tower
as Goodyear is not processing, using, storing or transporting volatile organic
compounds.
-12-
-------
(Ibs/clny)
TCI
f!
eU
X)
in
.n
HI
O
I
40
30
20
Tolal: 202.000 Ih
«0
-------
Maricopa County
Department of Health-'Services
;VISION OfP^SUCr!C.rl7r!
iv;:cr.:7!cr.:,ii Services
Kr. Dale Pasajci*
The Goodyear Tire & Suooer Company
i' ii *. Karhet Street
nH. "OP. OH -^3*5
"ha .:>l.i .-•' :ooa County Surasu of Air -Dilution Control (Sureau) has reviewed t'ra
cone arr.i r.atad crou.icwatar at tne Phoanix-Goofiyejr Airport Suoerfur.c s'ta.
Easad uoon tr.e aporexirr.ati on of potential emissions of vclatila ortar.ic
co~po-jr.es from tha air striooer, as s-or.itted in your Sa:te~:ar 23, 1333
corraspondanta, tns sir stripparniay oe proposed without a control :avica.
Tnara is a rac/.-i raner.t that Goooyaar apply for an i r.st a". 1 at i on pa rtr.it
pursuant to t.-.a 3y .-say's ?.-jla 21C (copy ar.plosad). 1 h»v» also ancles ad an
Swp-'itted is part of tr.a applicition for the pe~.it. Thera • -a r.orr.cl pe.rr.-. t
conditions whicr, tne Bureau racuiras racarcin; monitoring :.-.2 c:.sc.-.c.-:e of
tr.a air stripper. These pe~*. t conditions ire for your i r.f orr.ati on an: z^
not r.22C to P2 sipr.ed and raturr.ad ct tnis ti"2.
Should vo-j have any cuaitions reoardin; the abcva, p'iSJsa cor.tatt -* it (£C2)
2:S-=-31, ixt. 371.
'I.
?•-• o i i c He a \ t h I r.s \ r.sa r
Suraau of Air Pollutior. Ccr.zrpl
LMC:3 n
anc. ?,uie 20C, 210; '.nst jl 1 ati on Inforr.ition P.epuast;
Ss'p'e .?arTiit Concitions
cc: Kr. -.01 f vpn Oppar.fali, Fanna^ora Crai:
-------
Maricopa County
Department of Health Services
DIVISION or PUSLic HLALTH
al Services
OPERATING PERMIT CONDITIONS
1545 Cast Roojcvcli Si
Phocmv. ^fijor.a S5006
The soil vending system serving the Phoenix-Goodyear Airport site located at
}, Phoenix, Arizona is subject to the following Pe.-r.it Conc-.fi o.-s
(Maricopa County Bureau of Air Pollution Control Regulations, Rjle HOC,
Section 202).
1. .A test shall is made of the concentration of hydrocarbons emitted t: t~e
atmcspnere from the vapor discharge vent to determine tr.e emission rate ;. n
pounds per day. This test shall be conducted one (1) month after the
initial startup date of this system. .The following components snail ie
a-alyied for: benzene, toluene, xylene, ethyl benzene, miscellaneous
aromatics ard total hydroc-.-Dons. A written ccpy of tr,e test results
shall be submitted to the Bureau for review.
2. After the initial test is completed, future tests shall be conducted
quarterly and written copies of these test results submitted :: tr.e Sureau
for review. The components' tested for shall be the same as -n tr.e :.v, via!
test.
The operating permit issued shall be renewed annually, subject to cor.:' •;-,:;
with these Permit Conditions and all other applicable recul-tiers of tr.=
Sureau.
The Permit Conditions that are enumerated above are understood ar.d ag-e = d to
by the undersigned permittee. Please sign and return with your Installation
Permit Application.
Signed:
Title:
Date:
£NSn:3S/sh
orizons in ,755/;• Csrs'
-------
30
AIM DISCI lAHGi: Ol TOR,
(IbrAlny)
JJ
III
o
I-
20
10
0
0
0
..0
0
«»
:l:
\2
Year;
(0
CO
Toi;il:fi.:iiftiiv,
-i..-^..- i
|G
-------
THZ GOCDYiAX ?:?.! i S'JEHER
1*44 I. v.arkec Street
Akrcr., Ohio •; •; 3 " 5
r 29, 1553
Kr. Lawrence ;•'.. Crisa:ulli
Public Health i.-. = ineer
Bureau cf Air Pollution Cc-trc!
Mariccps Ccur.ty Health Department
'i S45 £• ?>ocsev3_t
Pr.csr.ix, Al S50C5
~.e: Air I.r.issisr.s from future Air Striopir.c To-%er
Pr.oer.ix-Goacyear Airocr- ("?GA")) Suoerfund Sita
Goodyear, Arizona
'y
Dear Mr. Crisaf ulli : :;
As you =ra av=r2, "ha Gcscyaar Tire & Suiber C:r.zir.-/
("Gocdvear Tire") has entered ir.tc ar. acreer.er.t ir. the fcr~ cf =.
Ccr.ser.t Decree vith the :J. S. ir.virsr.rr.er.tal rrctecticr. A™er.c--'
("Z?A") to treat rrour.dvater beneath the Phoer.ix-Gcccyear Airpcrt
Superfu.-.d site. The acraerr.er.t requires Goodyear Tire to :.r.st=l.
a crour.dvater vithdraval ar.d treatrer.t systen to treat water fro-
ths subur.it A aruif er ar.d rer.ove excess ccr.cer.traticr.s c: vets ,
catior.s indicate that acrrcMir.atel'.' " ,2CO ^-r. cf '--'iter ••••'! LI be
vithdravr. fror. sub^r.it A ir.d treated by rr.aar.s of a cached tcver
air stripper. Attached fcr your use is a -raph illustrati.-.r tr.s
cro;ected total daily er.issior. cf TCI frc- the air stricr-r.r
ur.it. Projected total vcc er.issicr.s represent only 2. -incr
increase over the TCI sr.issior. rates.
Based upon r.y understanding cf Karioopa County Air
220, Section 2C2, an air stripper cf the type beinc ccnsicered cy
Z?A fcr the PGA site is exer.pt fror. an air er.ission ccntrcl
recuire.r.snt fcr v^Cs unless the unit e.-its a quantity of v'CCs i
excess cf 40 Ibs./day. I: rr.y interpretaticn is correct, then -.=
air e.T.issicns centre's vc"'~ be recuired bv .'-'.ariccca Count" :~
• • •
-------
Mr. Lavrer.ce X. Crisafulii
Sester.ber 29, 1953
Pace 2
•he PGA site unit. 7 he unit. wi__ en.'/ e-i~, 21 2
se.Tie where in the vicinity of ten pounds per cay ever a .2 lat ive ly
short period cf ti.^e as shown en .tha graph.
I understand, however, that Peculation :::, Rule 32:,
Section 302 also allows y.aricopa County sc-e discretion en
"ccr.tainr.ent" cf air emissions from sources which e~i~ less than
^0 Irs./day V'OCs . 7he regulation requires ".material contain-en -"
such that vocs "will not u.-. r e a s o n a d 1 y e\-apcrate, lea-;, escape cr
be otherwise discharged." (Z-phasis added.)
.-.~ present our preliminary cost evaluations indicate a
carbon absorption unit installation cost ranee fro- 3230, CC-C to
S30-0,CrO. In addition, operating costs are projected toin crease
rrs.-n ' =c per :,COO gallons of water treated to 2Co per ',OC3
gallcr.s of water treated. At the projected flo-- rate of " ,2C3
cp~, the air stricpsr ooeratir.g cost would incre-ase frorr.
si 00, =::/year to r.'3S, OOO'/year. ' If operating costs are
considered alone, the cost of VGCs sir emissions controls 13
approximately 553,000-par tor. cf VCC re-oval. in lignt of this
cost data, it appears to r.e that the Section 302 prcyis ion --as
--- --a =-1 s- -a ' " "
/
~ reso-eotfullv reouest that vou re\riev the attach —ent
and -y discussion aoovs together with your air e.-.issions control
policy. rf -he facts i.-.dioite that air e.r.issior.s controls snould
r.ot be -andatsry or othervise required for the proposed air
striocer, olease res-or.d aoorocriatel'^ to r.e as soon as •-•r.u are
• • ' • . ••• • -^^~*~'~'
able. ?.23olutior. of this issue is very i.-portar.t to Seed-year
• ^ 3 ' *•* ,^ • • «• ^^^^^^<2^*^^ V" * * * '** A '•V^«»**. 2-*"^^a«**2**a-*
• " * ^ ^ ^ ^ •*• • • o • «» ^^ ^^ ^ • • ^ « ^ • «»
Ser.icr rr.viron.T.er.tal £.*
!* - r — • - = - a ? - v 1 — ^ - T, a -; - a '
------- |