~
United States
Environmental Protection
Agency
Office 01
Emergency and
Remedial Response
EPAIROD/R08-921063
January 1992
PB93-964405
&EPA
Superfund
Record of Decision:
Denver Radium (Operable
Unit 8), CO
......
Hazardous Waste Collection
;.;. .!,~..Resource Center
i;;:.~EP~ ';AegJOn. 3
~~iO, PA 19107
---1J. 3. I::rlvlronmemal ~rotectlon Agency
Region "' Hazardous Waste
Technical Information Center
84 1 Chestnut Street, 9th floor
Philadelphia, PA 19107 .
..~',.$
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NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of
the issuing agency. They contain materi&i which su~ but adds no fufther appIicabfe information to
the content of the document. All supptemental material is, however. c:cn1Bin8d in the administrative record
for this site.
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50272.101
REPORT DOCUMENTATION 11. REPORT NO. I ~ 3. Reciplenra AcceuIon No.
PAGE EPA/ROD/R08-92/063
4. Title and SubUUe 5. Report Date
SUPERFUND RECORD OF DECISION 01/28/92
Denver Radium (Operable Unit 8), CO
Ii.
Ninth Remedial Action - Final
7. Autho,(a) B. Perfo""ing Organization RepL No.
B. Perfo""lng Orgalnizatlon Name and Add..... 1~ ~o~aaWWo~Unh~
11. Contract(C) 0' G,ant(G) No.
(C)
(G)
12. Sponao,lng Organization Name and Addre.. 13. Type 01 Report & Pe,lod Covered
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
washington, D.C. 20460 14.
15. SUppiemantary NoI88
PB93-964405
16. Abatrad (Umh: zoo wom)
The 10-acre Denver Radium (Operable Unit 8) site is a former radioactive extraction
industry located in Denver, Denver County, Colorado. The site is divided into three
areas: the 5.9-acre S.w. Shattuck Chemical Inc. (Shattuck) property; the 4.3-acre
railroad right-of-way west of the Shattuck property; and nearby "vicinity" properties.
Land use surrounding the site is predominantly industrial, with some residential areas.
The site is located within the South Platte River drainage basin. From the 1920's to
1984, the Shattuck property was used to treat and process molybdenum ores, radium
slimes, and uranium compounds and ores. The railroad right-of-way has been operational
daily since the late 19th century with a spur to the Shattuck property. As a result of
extensive mining and processing, radioactive contaminated soil is widely scattered
resulting in a variety of radiation levels. A U.S. Bureau of Mines report led EPA to
field research 31 radioactive sites in Denver and Denver County. In 1983, EPA
conducted remedial investigations, which detected elevated levels of radon gas and
gamma radiation. A 1989 emergency removal action at one of the vicinity properties
included radon mitigation measures. This ROD addresses a final remedy for radioactive
contaminated debris, ground water, and soil, as OU8. Future RODs will address the
(See Attached Page)
17. Document Analysis L Deac,lptora
Record of Decision - Denver Radium (Operable Unit 8), CO
Ninth Remedial Action - Final
Contaminated Media: soil, debris, gw
Key Contaminants: inorganics (asbestos), metals (arsenic, lead), radioactive metals
b. IdentHle,alOpen.Ended Terms
c. COSA n FJeld/Group
1B. Availability Statement 19. Security Claaa (This Report) 21. ~ 01 Pagea
None 100
20. Security Class (Thia Page) 22. Price
None
See Instructions on Reverse 272 (4-77)
(See ANSI-Z3B.1B)
(Fonnerly NTlS-35)
Department 01 Commerce
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EPA/ROD/R08-92/063
Denver Radium (Operable Unit 8), CO
Ninth Remedial Action - Final
Abstract (Continued)
remaining contaminated media at 11 OUs not addressed by the previous seven RODs at the
Denver Radium sites. The primary contaminants of concern affecting the soil, ground
water, and debris are inorganics, including asbestos; metals, including arsenic and lead;
and radioactive materials.
The selected remedial action for this site includes demolishing and decontaminating
buildings, tanks, and equipment onsite; temporarily storing debris from vicinity
properties onsite at the Shattuck area, pending either offsite disposal and/or scrap
recycling, or salvaging of debris; disposing of aSbestos-containing material from
buildings offsite; conducting pilot scale treatability studies during remedial design to
optimize stabilization design; excavating and transporting 5,000 cubic yards of
radium-contaminated soil from the railroad rights-of-way and 6,000 cubic yards from the
vicinity properties; consolidating these with 38,500 cubic yards of soil from the
Shattuck property, and treating the soil onsite using cement-based stabilization; placing
a cap over the stabilized material, and revegetating the area; filling previously
excavated areas with clean fill; testing for, remediating and disposing of any RCRA
hazardous waste offsite; allowing the ground water to naturally attenuate; monitoring
ground water and air; and implementing institutional controls, including deed, land, and
ground water use restrictions. The estimated present worth cost for this remedial action
is $26,600,000, which includes an annual O&M cost of $120,000.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil action levels are based on Nuclear Regulatory Commission and
Department of Energy standards for Radium-226, exceeding 5 pCi/g above background in the
top 15 cm of soil and 15 pCi/g above background in any layer below the top 15 cm;
thorium-230, 42 pCi/gi uranium; 75 pCi/gi and risk-based standards for arsenic 160 mg/kg;
selenium 490 mg/kg; and lead 540 mg/kg.
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, JA..."'1,TARY 23, 1992
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DENVER RADIUM SITE
OPERABLE UNIT VIII
DECLARATION FOR THE RECORD OF DECISION
-------
DENVER RADIUM SITE
OPERABLE UNIT VIII
DECLARATION FOR THE RECORD OF DECISION
site Name'and Location
Denver Radium site Operable unit VIII
Denver, Colorado
statement of Basis and Purpose
This decision document presents the selected remedial action for
Operable Unit VIII of the Denver Radium site in Denver, Colorado,
chosen in accordance with the comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and, to
the extent practicable the National contingency Plan (NCP), 40 CFR
, Part 300. This decision document explains the factual and legal
basis for selecting the remedy for this site.
The Colorado Department of Health has been the lead agency for the
remedial investigation and feasibility study and both concurs with
and recommends the selected remedy to the U. S. Environmental
Protection Agen~~ (EPA). The information supporting this remedial
.' action decision is contained in the administrative record for this
-'.'site. ' . ,
Assessment of the site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
Description of the RemedV
, The Denver Radium Superfund site consists of 11 operable units
involving a total' of more than 40 properties located within the
city of Denver which are contaminated by radioactive residues as a
result of mineral processing operations.
. "
Operable unit VIII encompasses the property located at 1805 "South
Bannock Street, adjacent, and vicinity properties.
The selected remedy for Denver Radium site Operable unit VIII is
stabilization and disposal of the contaminated soils on-site. The
selected remedy addresses the principal threats at the site, which
are associated with radium contaminated soils and include radon gas
-------
emissions and direct exposure to gamma radiation.
entails:
The remedy
* Demolition and off-site disposal of existing facilities on
the 1805 South Bannock property.
* Excavation, consolidation, stabilization, and on-site
disposal of an estimated 50,000.cubic yards of contaminated
soils. Stabilization of the contaminated soils entails mixing
the soils with a cement additive resulting in a concrete-like
material which physically and chemically stabilizes the
contaminated soils. Stabilization will reduce the mobility of
contaminants and radon emanation. A cap will be placed over
the stabilized materials to. protect the materials from erosion
and weathering, and to shieldqamma radiation.
* Institutional controls, maintenance, and monitoring will be
used to supplement the remedy and to assure the protectiveness
of the selected remedy is maintained into the future.
Ground water contamination is addressed through source control
using stabilization to immobilize contaminants. Attenuation of the
contaminated groundwater plume will be monitored. The ground
water portion of the remedy may be subject to future modification
if remedial objectives for ground water are not attained within a
reasonable time frame.
Statutorv Determinations
. - n The selected remedy is protective -cf human heal th and. the
.-..environment, complies with Federal and State requirements that are
. legally applicable or relevant and appropriate to the remedial
action, and is cost effective. This remedy utilizes permanent
solutions and alternative treatment technologies to the maximum
extent practicable. It satisfies the statutory preference for
remedies that employ treatment to reduce toxicity, mobility, or
volume, as a principal element.
Because this remedy will result in hazardous substances remaining
on-site above health based levels, and because the ground water
remedy involves source control and attenuation of existing
contamination over time, a review will be conducted no less than
every five years after commencement of remedial action to ensure
that the remedy continues to provide adequate protection of human
health and the environment.
'-,.
"
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w~
Reg' nal Adm1n1strator (R gion VIII)
u. . Environmental Protection Agency
Di~e f! ~nment
Department of Health
state of Colorado
.-.- -- ...---. .. ~..
0- .".
Ilz-/Ll----
~
i~7)f2-
ate
"
"
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DENVER RADIuM SITE
OPERABLE UNIT VIII
DECISION Sm~Y FOR THE RECORD OF DECISION
.'-
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1.0 site
2.0 site
2.1
2.2
3.0
4.0
5.0
6.0
DENVER RADIUM SITE OPERABLE UNIT VIII
DECISION SUMMARY FOR THE RECORD OF DECISION
TABLE OF CONTENTS
Name, Location, and Description. . .
. . . .
History and Enforcement Activities. . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . .
operational History. . . . . . . . . . . . . . . .
Highlights of community Participation. .
. . . .
. . . .
Scope and Role of Operable ynit Within site strategy. .
Summary of Site Characteristics . . . . . . . . .
5. 1 Soils. . . . . . . . . . . . . . . . . . . .
5.1.1 Shattuck Property. . . . . . . . . . . . . .
5.1.2 Railroad Rights-of-way. . . . . . . . . . .
5.1.3 Vicinity Properties. . . . . . . . . .
Facilities. . . . . . . . . . . . . . . . . .
Air. . . . . . . . . . . . . . . . . . . . . . . .
Ground water. . . . . . . . . . . . . . . . . . .
5.2
5.3
5.4
Summary of site Risks. . . . . . . . . . . . . . . . .
6.1 Human" Health Risks. . . . . . . . . . . . .
6.1.1 Principal Threats posed by the site. . . . .
6.1.2 Additional Risks. . . . . . . . . . . . . . .
6.2 Enviror~ental Risks. . . . . . . . . . . . . . . .
Description of Alternatives . . . . . . . . . . .
7 . 1 Screening. . . . . . . . . . . . . . . . . . . . . .
7.2 summary of Alternatives. . . . . . . . . . . .
7.2.1 Common Elements. . . . . . . . . . . . . .
7.2.2 Description of Alternatives. . . . . . . .
7.0
8.0
comparative Analysis of Alternatives . . . . . .
8.1 Evaluation of Alternatives. . . . . . . . . . . . ."
8.1.1 Overall Protection of Human Health
and the Environment. . . . . . . .
8.1.2 Compliance with Applicable or Relevant and
Appropriate Requirements. . . . . .
8.1.3 Long-term Effectiveness and Permanence.
8.1.4 Reduction of Toxicity, Mobility or
Volume through Treatment. . . . . . . . .
Short-Term Effectiveness. . . . . . . . . . .
Implementabili ty . . . . . . . . . . . . e".".
Cost. . . . . . . . . . . . . . . . . .
community Acceptance. . . . . . . . . .
state Acceptance. . . . . . . . . . . .
8.1.5
8.1.6
8.1.7
8.1.8
8.1.9
i
1
3
3
5
6
7
7
7
9
13
13
14
15
17
20
22
22
24
29
29
30
31
32
34
39
39
39
42
44
46
47
48
49
50
50
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TABLE OF CONTENTS (CONTINUED)
9.0
Selected Remedy. . . . . . . . . . . . . . . . . . . .
9.1 Description of Selected Alternative. . . . . . . .
9.1.1 Removal and Reuse or Disposal of Facilities.
9.1.2 Excavation. and stabilization of
contaminated soils. . . . . . . . .
9.1.3 Institutional Controls, Maintenance,
and Monitoring. . . . . . . . . . . . .
9.1.4 Storm Sewer Discharge. . . . . . . . . . . .
9.'2 Remediation Requirements and Performance
Standards. . . . . . . . . . . . . . . .
9.2.1 Facilities . . . . . . . . . . . . . .
9 . 2 . 2 Soils. . . . . . . ... . . . . . . . . . . .
9.2.3 Ground Water . . . . . . . . . .
9 . 2 . 4 Air. . . . . . . . . . . . . . . . . .
9.3 significant Changes. . . . . . . . . . . . .
Statutory Determinations. . . . . . . . . . . .
10.1 Protection of Human Health and the Environment
10.2 Compliance with Applicable or Relevant and
Appropriate Requirements. . . . . . . .
10.2.1 contaminant-specific Requirements. . . . . .
10.2.2 Action-Specific Requirements. .
10.2.3 Location-Specific Requirements. . . . . . .
10.3 Cost Effectiveness. . . . . . . . . . . . .
10.4 Utilization of Permanent Solutions and
Alternative Treatment Technologies to
the Maximum Extent Practicable. . . . . . ..
10.5 Preference for Treatment as a Principal Element. .
10.0
Appendix A
Federal and State of Colorado Applicable or
Relevant and Appropriate Requirements
Denver Radium site Operable unit VIII
Responsiveness Summary
Appendix B
ii
50
51
53
54
57
60
60
60
61
63
64
65 .
68
69
70
70
71
71
71
72
73
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Figura
Figura
1-1
1-2
Figura
Figura
FIGURES
Sita Location
. . . . . . . . . .
........
Map Showinq Shattuck Property
and Facilities. . . .
..........
5-1 Areal Extant of Radium-226 contaminatad Soils. . .
5-2
Figura
5-3
Figura 5-4
Table 5-1
Table 5-2
Table 5-3
Table 6-1
Table 6-2
Table 6-3
Table 9-1
Table 9-2
Tabla 9-3
Potentiometric Surface Map
.......
.....
Block Diagram showing Relationship between
Bedrock, Surfaca, and Ground water Flow. .
Storm Sewer Sampling Locations. . . . . . . . . .21
TABLES
Summary of Radiologic Data Measurements
. . . . .
Sampling Data for Non-radiological Inorganic
Constituents. . . . . . . . . . . . . . . .
Indoor Air Data Summary, Shattuck Property
Baseline Radioloqical Risks. .
. . . .
.......
Hazard Quotients
..........
. . . .
Non-Radioloqical Cancer Risks
.....
.....
Cost Estimate for Selected Remedy
Action Levels for Soils
........
. . . . . .
. . . .
Disposal criteria
. . . . . .
.......
iii
2
4
8
18
19
10
11
16
25
27
28
52
55
58
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DENVER RADIUM SITE
OPERABLE UNIT VIII
DECISION SUMMARY FOR THE RECORD OF DECISION
1.0
SITE NAME. LOCATION AND DESCRIPTION
Denver Radium site. Operable unit VIII is located in southwest
Denver, northeast of the intersection of Evans Avenue and Santa Fe
Drive. Tpe site includes the 5.9 acre S.W. Shattuck Chemical
Company, Inc. ("Shattuck") property located at 1805 South Bannock
Street, the 4.3 acre railroad rights-of-way located to the west of
the Shattuck property, and nearby ("vicinity") properties located
within the area bounded by South Santa Fe Drive (u.S. Highway 85),
South Broadway, Jewell Avenue, and Mexico Avenue (Figure 1-1).
South Santa Fe Drive borders the site west of the railroad rights-
of-way. Overland Park Golf Course lies west of South Santa Fe
Drive. The South Platte River forms the west boundary of the golf
course~
i
The topography of the area surrounding the site is relatively flat
. and generally slopes to the north and west toward the South Platte
River. Most of the area, with the exception of the Overland Park
Golf Course, is typical urban development ranging from industrial
to residential.' .
-'.
The Shattuck property is located in an area of the city designated
as commercial/industrial. Land use within two blocks south and
east of the Shattuck property is predominantly industrial, although
some residential use exists.' The industrial/ commercial area
extends from the Shattuck property north for several blocks
following the railroad lines.
Residential areas are located three blocks east of the Shattuck
property (east of South Broadway) , and south of the golf course and
west of South Santa Fe Drive (approximately 600 feet southwest of
the Shattuck property). Water for domestic use is supplied to the
area by the Denver Water Department.
to:'
The site is located within the drainage basin of the South Platte
River, which is located approximately 3000 feet west of the site.
A shallow unconfined aquifer exists below the Operable unit VIII
site. The shallow aquifer is perched on bedrock and merges with
the alluvial aquifer beneath the floodplain of the' South Platte
River. The ground water is not used as a drinking water source.
Ground water for Operable Unit VIII generally flows west across the
site and then northwest toward the South Platte River.- Ground
water contours within the alluvium indicate that the South Platte
River adjacent to the Overland Park Golf Course is a gaining reach
that receives discharge from the ground water system.
1.
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ure 1-1
00
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Planview of the Shattuck site
(the Shattuck property, the
,Railroad property, and the
surroun,;;ne vicinity).
'""
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The facilities located on the Shattuck property (figure 1-2)
include: six permanent buildings; miscellaneous. storage sheds;
underground storage facilities; above ground storage tanks; process
equipment and piping; and asphalt and concrete paving. Surface
water on the site generally follows the topography toward the
northwest. A runoff catchment basin, which captures a limited
amount of surface runoff, is located on the Shattuck property south
of Building 6. The rail lines are elevated above the surrounding
grade, impeding the flow of surface runoff, and creating some
.ponding during rainfall.
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 INTRODUCTION
The Denver Radium site had its beginnings with the united States
radium, vanadium, and uranium extraction industry of the early
1900s. The United States Bureau of Mines, in cooperation with
private industry, established the National Radium Institute (NRI),.
which successfully developed radium processing in the Denver area.
In 1979, EPA noted a reference to the NRI in a 1.91.6 united States
Bureau of Mines Report. subsequent field research revealed the
presence of thirty-one radioactive sites within the city and county
of Denver. After identifying these properties, the Radiation
control Division of the colorado Department of Health (CDR)
notified affected property owners of the presence of radiologic
contamination. Pursuant to a cooperative agreement with EPA, CDR
initiated engineering assessments of the majority of the identified
properties. In October 1.981, the Denver Radium site was placed on
the Superfund Interim Priorities List.. The site was included on
the National Priorities List on September 8, 1.983. .
In December 1.983, EPA began a remedial investigation to determine
the nature and extent of the contamination present on those
properties which the State did not previously study, as well as
several additional properties where contamination was suspected.
with the additional properties, the Denver Radium Site totals over
forty properties.
Because of the complexity of the Denver Radium site, response
actions were divided into operable units based primarily upon site
conditions and location. The Site was grouped into eleven operable
units, the property located at 1805 South Bannock Street being.
Operable Unit VIII. In April 1986, EPA published the Denver Radium
site Remedial Investigation report, which addressed all.eleven
operable units.
Further information was needed prior to proceeding with the cleanup
of Operable unit VIII. The EPA notified potentially responsible
parties of the opportunity to perform a detailed remedial
3
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-------
investigation and feasibility study for Operable unit VIII.
Although negotiations with the S.W. Shattuck Chemical company, Inc.
took place, no potentially responsible parties elected to perform
the studies.. In conjunction with a . grant from the EPA, CDH
performed the remedial investigation and feasibility study which
support this Record of Decision.
CDH began the remedial investigation in November 1988. since 1979,
CDH, the EPA, and Shattuck have conducted various studies of the
site media, which have included a substantial number of soil and
ground water samples. The remedial investigation study evaluated
the existing data and included collection of additional data to
characterize the nature and extent of the contamination.
During the remedial investigation, additional radiological
contamination was discovered to .the east and north of the 1805
South Bannock property. The extent of this contamination was
evaluated by the EPA. These areas are referred to as the "vicinity
properties" in this Record of Decision and the supporting
documentation. In August 1989, EPA conducted an emergency removal
action at one of the vicinity properties, which involved
installation of an active radon reduction system in order to reduce
excessively high levels of radon present at a commercial property.
A surface impoundment utilized as an evaporation pond when the 1805
South Bannock facility was in operation was excavated and closed in
1987, pursuant to a consent decree between CDH and the S. w.
Shattuck Chemical Company, Inc.
2.2
OPERATIONAL HISTORY
The Shattuck property has been the location of several mineral
processing operations including the processing of tungsten ores,
carnotite ores (for uranium and vanadium), radium slimes,
molybdenum ores, and depleted uranium. The contamination of the
site is due to the historical use of the site for various mineral
processing operations. Approximate time frames for some of the
processing activities that have taken place at the site follow:
1920s -
Treatment of molybdenum ores and extraction of
ferric vanadate from vanadium and uranium ores or
by-products.
1930s -
Processing of radium slimes
as well as production of
compounds and other rare
carnotite ores.
for recovery of radium,
radium salts, uranium
mineral products from
1940s -
Processing of uranium compounds and molybdenum.
1950s -
Processing of uranium ores.
5
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.
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1960s -
Unknown
1970s &
1980s
Processing of
rhenium.
uranium
compounds,
molybdenum and
From 1969 to 1984, the operations at the facility consisted
primarily pf processing molybdenite ,for the recovery of molybdenum
compounds, with recovery of rhenium as a by-product. In addition,
a small batch operation for the production of uranium products from
depleted uranium existed. Operations at the Shattuck facility
ceased in 1984. The Shattuck property is currently fenced, and
access is restricted by security provided by Shattuck.
The railroad rights-of-way include two rail lines which have been
operating since the late 19th century. In addition, a rail spur
onto the Shattuck property was in place by 1915. The two rail
lines are utilized as main lines through the Front Range and handle
a total of about twenty to thirty general freight and coal trains
per day. The east rail line is located on property owned by the
Atchison, Topeka & Santa Fe Railway Company, and the western line
.is owned by the Denver & Rio Grande Western Railroad Company. At
present, one line is utilized for northbound traffic and the other
is utilized for southbound traffic.
'3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The pUblic participation requirements of the Comprehensive
Environmental Response, compensation, and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), sections 113(k) (2) (B) (i-v) and
117 were met in the remedy selection process.
A mailing list of persons interested in Operable Unit V!!I was
developed to keep the public informed as to the progress on the
Operable Unit VIII remedial investigation/feasibility study. CDH
has published fact sheets at project milestones to inform the
public of opportunities for input. CDH representatives have also
met with a local community group and the local City Council
representative to discuss the project.
A draft of the remedial investigation report was made available to
the public in December 1990. The comments received on the draft
report were considered in revising the document. However, formal
response to these comments was not prepared. The formal public
comment period for the remedial investigation, baseline risk
assessment, feasibility study, and proposed plan began March 29,
1991, and closed May 29, 1991. A public meeting summarizing the
remedial investigation/feasibility study and soliciting comments
from the public on the proposed plan was held on April 11~ 1991.
Notice of the pUblic meeting was sent to persons on the mailing
6
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list and was published in the Denver Post and the Rockv Mountain
News on April 7, 1991. A transcript of the public meeting is
available in the Administrative Record. A summary of significant
comments, wri tten or . oral, and EPA' s. and CDH' s response is
contained in Appendix B of this Record of Decision. .
The Decker Branch of the Denver Public Library, located at 1501
South Logan, has been used as a repository in order to make the
primary documentation available at a location close to the site.
In addition, the administrative record is available at EPA and CDH
offices in Denver.
This decision document presents the selected remedial action for
the Denver Radium site, Operable unit VIII, Denver,. Colorado,
chosen in accordance with CERCLA, as amended by SARA, and to the
extent practicable, the National contingency Plan (NCP). . The
decision for the remediation. of the site is based on the
administrative record.
4.0
SCOPE AND ROLE OF OPERABLE UNIT WITHIN SITE STRATEGY
The Denver Radium site consists of over 40. properties which are
grouped into 11 operable units. The Operable unit VIII Record of
Decision is for the . last of the operable units addressing
radiologic contamination. The Records of Decision for the other
operable units addressing radiologic contamination identified
excavation and permanent off-site disposal as the ultimate remedy
in each case, except operable Unit VII. (Operable unit VII
includes sections of nine Denver streets where contaminated
materials will be left in place based on the limited threat they
pose to public health and the environment.) At the time the
previous Records of Decision were issued, a permanent disposal site
was not available. The Records of Decision incorporated various
combinations of consolidation and temporary storage units until a
permanent off-site repository would be available. Since that time,
an off-site permanent repository has become available in Utah.
Remedial action at these operable units is proceeding with a
scheduled completion date of September 1992.
5.0
SUMMARY OF SITE CHARACTERISTICS
5.1. SOILS
Radiologically-contaminated soils have been identified on the
Shattuck property, the railroad rights-of-way, and the vicinity
properties. Figure 5-1 shows the areal extent of radium-226
contaminated soils. Areas are considered contaminated if the
radium-226 concentration in soil exceeds 5 pCijg above background
in the top 15 cm of soil or 15 pCijg above background in any layer
below the top 15 em (40 CFR 192.12).
7
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Figure 5-1 ArE".al Extent of Radium-226 I {
Contruminated Soils
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Radioactive soil contamination on the Shattuck property covers
approximately 230,000 square feet. The estimated volume of
contaminated soil on this property is 38,500 cubic yards.
Radioactive'soil contamination covers approximately 34,000 of the
187,000 square foot railroad rights-of-way. The volume of
contaminated materials on the railroad rights-of-way is estimated
to be greater than 4,500 cubic yards.
The volume of contaminated soil on the vicinity properties is
estimated to total 6,000 cubic yards.
These estimates are based primarily on radium-226 contamination~
Additional metals contaminatioI) including radioactive lead-210,
thorium-230, and uranium, as well as non-radioactive metals such as
lead and arsenic have also been identified in site soils. Based on
radioactive equilibrium ratios and limited laboratory analysis, it
is estimated that 500 cubic yards of the estimated volume on the
Shattuck property would require remediation due to thorium-230 and
uranium contamination. The majority of the additional contaminants
are co-located with the radium-226 contamination and are expected
to be addressed by cleanup of the radium-contaminated soils. The
shaded areas on figure 5-1 show the location of the contaminated
soils. Table 5-1 summarizes gamma radiation measurements and table
5-2 summarizes the sampling data for non-radiologic inorganic
constituents. '
5.1.1
Shattuck ProDertv
Discussion of the Shattuck property is divided into three areas:
(1) the buildings and process area located in the center of the
property; (2) the open space areas to the north and south; and, (3)
the closed evaporation pond which is located in the north open ,area
of the property (see figure 1-2).
Buildings and process area:
The soils throughout most of the buildings and process area are
contaminated. The highest measured one-meter gamma radiation
exposure rate in this' area was 2800 microroentgensjhour near the
southeast corner of Building 6. Subsurface radiation data
indicates depths ranging from one to nine feet, with an average
depth of about 40 inches and an average equivalent radium-226
concentration of about 90 pCi/g. .
Open space areas:
The open areas of the Shattuck property to the north and south of
the buildings and process area generally exhibit contamination
throughout the area except the southern area near the perimeter of
'the property, the area near the southwest corner of Building 6, and
the areas east and south of the closed evaporation pond. Depth of
9
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Table 5-1
SUMMARY OF RADIOLOGIC DATA
One meter gamma measurements
reported in microroentgen per hour
Outdoor Measurements
# of
Location . low hiqh ~ measurements
Process/buildings 20 1460 85 75
area
Open areas north 15 1300 67 138
& south of process
/buildings area
Closed lagoon area 16 22 18 9
Railroad right- 14 454 40 147
of-way
Overland Park
Golf Course
(background)
16.1
30
Indoor Measurements
Location
Building 1
Building 2
Building 3
Building 4
Building 5
Building 6
low
21
14
20
20
20
15
hiqh
290
20
450
85
50
230
~
41
17
70
49
29
41
to
-------
Table 5-2
InorJ~anics Sampled in Soils.
~
~
. Chemical Average Maximum Frequency of Range of Sample Range of Detected Background
(mgf1;g) (mgf1;g) Deleclioll Quanlilalion Concentration . Levels (mg/kg)
limils (mcJkg) (mg/kg)
Aluminum 9121 23.600 10/10 2980 . 23600 . 12550
Alllimoll)' 7 26 7/10 1.6 . 1.9 3.5 . 26 1.11
Arscnic .14 598 63/67 0.45 . n.5 1.2 . 598 3.5
BariulII 7H6 n~o 10/10 22.3 . 3340 221
IIclyllililll 0.2 0.6 3/10 0.03 . 0:0.1 0.38 . 0.6 0.9
C atlm i UIII 2.6 10.8 9/21 0.34 . 0.41 0.8 . 10.8 0.6
Calcium 1221-1 J0500 10/10 814 . 30500 4935
l'hflllllilllll n 1M 11)/2(1 ().1)5 . 1.05 2.5. 1M 12.4
C oha II 6 33 5/10 0.45 . 0.55 2 - 33 102
C oppcr 1220 7730 26126 44 . 7130 26
Iron liB 18 47600 10/10 7890 . 47600 110.50
-------
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Table 5-2 (Cont.)
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Chemical A vcrage Max i IIIUIII Frequcncy of Range of Sample Range of Delecled Background
(111 gJ1; g) (mgJ1; g) Delection QuaOlitation ConceOlr.tlion Levels (mg/kg)
Limils (mglkg) (mglkg)
Lead 297 1260 26f}.6 7.2 - 1260 54
MagnesiulII 2086 7440 10/10 793 . 7440 3145
Mangan~s~ 245 471 lO/tO 73 . 471 481
Mercury 2 47 15/26 0.05 . 0.35 0.2 - 47 0.051
Nidcl 28 106 10/10 7.6 - 106 10.1
Potassium 2113 99-tO 10/10 180.9940 3410
Selenium 152 7980 56/66 0.18 - 14.25 0.71 . 79aO 0.221
Silvcr 2.6 5.7 17/26 0.75 . 0.90 2.3 - 5.7 0.31
Sodium 1088 5750 10/10 165 - 5750 256
llmlliulII :u 4.7 81M 0.35 - 4.7
VanadiulII 1159 4190 24/14 14.1 .4190 31
Zinc 167 432 to/tO 35.6 - 432 90
Molybdcnum 48800 48800 1/1 48800
I n,t lIIawill "'.. &/III)" wi fOI hul 110' JcttCltJ. lllc lI!lxilleJ nllmelkl! vduc is one.hllf Ihe umple qUllilililioo limit.
-------
. contamination for these areas. ranges from 0.5 to over 14.5 feet
with an average depth of about 39 inches and an average equivalent
radium concentration of about .69 pCi/g.
Closed evaporation pond:
Direct gamma radiation measurements on the asphalt surface of the
closed pon4 indicate no surface contamination in this area. Soil
. immediately beneath the asphalt cover exhibits essentially
background concentrations of radioactive contaminants. However,
radium-226 contamination exists from about 6 feet to about 7.5 feet
below the surface over the western two thirds of the former pond
area. Thorium-230 contamination is estimated to exist in this area
from a depth of about 5.5 feet to approximately 8.5 feet.
5.1.2
Railroad Riqhts-of-Wav
The 4,500 cubic yard estimate of contaminated soil on. the railroad
rights-of-way includes nearly the full length of the area between
the east rail line and the Shattuck property, as. well as some
limited areas located to the west of the rail line. The estimated
depth of contamination is 0.5 to 2.5 feet along the southern
portion and 5 feet for the northern portion.
Although the soil directly beneath the rail line was not sampled,
the data for the surrounding area indicate that radium
contamination beneath the line is likely. The highest radium
equivalent value measured in the railroad rights-of-way was 570
pCi/g.
5.1.3
Vicinitv Properties
EPA performed the assessment of the vicinity properties after
surface gamma scans indicated the presence of radioactivity on
properties in the vicinity of the Shattuck property. The estimated
volume of these materials is 6,000 cubic yards. The following is
a summary of the primary deposits on the vicinity properties:
o The 1860 South Bannock Street property. Radium-
contaminated soils are located beneath the floor slab of a
building, the concrete driveway and parking area, and beneath an
asphalt covered area extending beyond the property to the north and
south. The deposit is approximately 2,700 cubic yards and extends
to a depth of over eight feet. In August 1989, an emergency
removal action was conducted at this property because of the very
high levels of radon gas and decay products measured within the
building. The removal action involved radon mitigation measures,
including sealing slab joints and installing a vent system.
contaminated source materials were not removed.
13
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o The area adjacent to the west side of South Bannock
Street from approximately 1700-1830 South Bannock. The
contaminated area consists of uncovered soil, as well as asphalt,
concrete, driveways, and parking areas. The deposit includes
approximately 1,300 cubic yards of radium-contaminated material
ranging to a depth of over three feet. .
o The 1822 South Bannock Street property. Radium-
contaminated soil exists in the fill material beneath the concrete
floor slab of a building and adjacent to the east side of the
building. The deposit includes approximately 250 cubic yards of
material and extends to a depth of approximately 2.5 feet.
"
o The 1788 South Acoma Street residential property.
Radium-contaminated soil is limited to exterior soils and ranges to
about two feet deep, with an estimated volume of 220 cubic. yards.
o In addition, 1,100 cubic yards of radium-contaminated
soils are estimated to exist beneath South Bannock gtreet. This
estimate is based on adjacent investigations; investigation into
the street was not performed because of the presence of numerous,
utility lines.
\
'.
The remedial investigation did not attempt to appraise the extent
of possible uranium and thorium-230 contamination for the railroad
and vicinity properties. Based on the data from the Shattuck
property, it is possible that the total amount of radiologically-
contaminated soils requiring remediation would be higher than
estimated because of radiological constituents other than radium-
226 or lead-210. However, such additional .materials will not
influence the remedy selected in this record of decision.
.'
'.
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~~
5.2
FACILITIES
Buildinqs:
.'
Based on procedures outlined in the Nuclear Regulatory Commission
(NRC) Guide 1.86, radioactive contamination was identified in five
of the six permanent buildings on the Shattuck property. The
volume of the radiologically-contaminated material associated with
the buildings is esti:nated at approximately 2,095 cubic yards.
This estimate includes 100 percent of three of the buildings and
the floor slabs of two of the buildings. At least one building is
contaminated with depleted uranium.
. .
-,
;"'1
The contamination of the buildings is associated with radioactive
constituents which had been processed on the site. Radium-226 and
uranium have been identified in building material samples. Based
on visual inspection, radiologically-contaminated building
materials which are suspected to contain asbestos are relatively
abundant in two of the contaminated buildings, with minor amounts
in a third building.
14
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Asbestos-containing material which is not radiologically-
contaminated was not identified but may exist in the three other
buildings. Asbestos-containing building materials require special
handling and disposal practices to prevent the inhalation of
asbestos particles. .
Tanks:
Direct radiation measurements showed elevated levels of total alpha
activity for five tanks, indicating these tanks have been
contaminated by the processing operations at the si te. The
averages of the total alpha activity on the five tanks are greater
than the NRC Regulatory Guide 1.86 average. However, no maximum
measurements exceeded the NRC maximum. The radioactive
contamination associated with the tanks is at relatively low
levels, and it is expected that the tanks can be adequately
decontaminated.
5.3
AIR
Atmospheric contaminants of concern at the site consist primarily
of radon, a radioactive gas produced by the decay of radium-226,
and airborne thorium-230 particles associated with soil
contamination.
Air investigations included indoor and outdoor measurements for
radioactive contaminants and organic vapors. Of the six buildings
on the Shattuck property, three have exhibited concentrations of
radon gas and its decay products in excess of the EPA guideline of
0.02 working levels (WL), a measure assQciated with radon. Given
the gamma radiation levels associated with two additional
buildings, it is expected that two more of the six buildings may
also periodically exceed the EPA guideline. Table 5-3 is a summary
of the indoor air data for the Shattuck property.
outdoor air monitoring exhibited low atmospheric concentrations of
radioacti ve contaminants. Measurements of alpha acti vi ty and
thorium-230 concentrations were in the 10-14 to 10-15 microcuries per
milliliter range or lower. Air monitors attached to workers
performing the remedial investigation yielded up to 10-12 microcuries
alpha activity per milliliter for activities disturbi~g the soils.
The vicinity property upon which an emergency removal was performed
to mitigate radon concentrations had very high radon concentrations
(up to 4.6 working levels) prior to the removal action. The
removal action has reduced radon levels; however, gamma radiation
still poses a potential risk. Measurements of radon at other
vicinity properties where radium-contaminated .soils have been
identified were not in excess of the EPA guideline of 0.02 working
levels.
15
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Table 5-3
Denver. Radium Site Operable Unit VIII
On-site Indoor Ai r Sununary
Rn-222 Rn-222 Progeny
Concentration Concentration
Building Range Range. HNu Data
Number (cCill) (WL) 19m!l Conditions Sou rce
1 13.1 - 21.6 0.048 - 0.092 < 1 Open Versar, 1989
1 41.8 - 139.3 0.085 - 0.146 N/A Closed ARIX, 1982
2 < 0.6 - 0.002 < 1 Open Versar, 1989
3 0.4 - 2.3 0.002 < 1 Open Versar, 1989
3 4.0 - 14.8 0.012 - 0.038 N/A Closed ARIX, 1982
4 1 4.1 0.001 < 1 Open Versai, 1989
4 4.5 - 5.4 0.014 - 0.019 N/A Closed ARIX, 1982
5 2 3.8 0.010 < 1 Open Versar. 1989
6 0.5 - 1.4 0.002 < 1 Open Versar, 1989
16
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Indoor .and outdoor measUrements of organic vapors were less than
the detection limit of approximately one part per million benzene
equivalent. ..
5.4
GROUND WATER
Data from the supp~emental monitoring system installed during the
remedial. investigation was used in conjunction with data from
monitoring performed by the Shattuck Chemical Company to
characterize ground water flow and quality for the site.
potentiometric surface maps (figure 5-2) prepared during the
. remedial investigation indicate that. contaminated ground water from
the site flows in a west to northwest direction from the site and
is contained beneath the Overland Park Golf Course. The golf
course obtains its water from ponds supplied from the South Platte
River. There is no current use of ground water affected by the
site. contaminated ground water from Operable unit VIII does not
flow beneath the residential area located to the south of Overland
Park Golf Course. Water for domestic use is supplied to the area
by the Denver Water Department.
The flow system immediately below the site flows into a larger flow
system associated with the South Platte River. The estimate of the
ground water velocity is O.51feetjday beneath the site. At this
rate, ground water takes an estimated 2.7 years to reach the
eastern edge of overland Park Golf course. Beneath the golf course
the hydraulic gradient increases dramatically as the shallow
aquifer beneath the site drops into the valley that was carved by
the South Platte River during the Pleistocene era (figure 5-3).
The valley is now filled with alluvial sand and gravel. The
velocity of the ground water increases through this section, with
the total elapsed time for ground water to travel from the site to
the ~outh Platte River estimated to be slightly more than three
years.
The on-site alluvial ground water is contaminated with gross alpha
radioactivity and gross beta radioactivity in excess of Safe
Drinking Water Act Maximum contaminant Levels (MCLs), and uranium
in excess of the range of proposed standards. The off-site
.alluvial aquifer downgradient from the site continues to exhibit
significant concentrations which then falloff to background levels
as the aquifer is diluted by the system underlying the Platte
River. The primary radioactive contaminant in the ground water is
uranium. .
Volatile organic compounds were detected in concentrations-above
MCLs in an upgradient well, on-site wells, and downgradient off-
site wells. Data from the upgradient well provide strong evidence
that significant off-site sources of volatile organic compounds,
specifically 1,1, 1-trichloroethane, have affected ground water.
Soil borfng data indicate on-site sources of tetrachloroethene and
17
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-... -- .
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MAP
VI~ A I
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WATER -!.ol
TABLE A i
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BEDROCK ~!
SURFACi:
FIGURE 5~3
LEGEND
~ OPERABLE UNIT VIII .
~///// ~ RESIDENTIAL AREA
~ G W FLOW DIRECTION
MW-1 I
.
MONITORING WELL
RESIDENTIAL WATER
SUPPLY WE!.!.
MW.3
VMW.2
SHB-1A, 2A, SA, 4, 10,20
SH8-9C
VMW-1
, SH8-12B
VMW-'3
VMW-V3
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BLOCK DIAGRAM ILLUSTRATING RELATIONSHIP BETWEEN
BEDROCK, SURFACE AND GROUNDWATER FLOW-
DENVEM RADIUM SITE, OPERABLE UNIT VIII.
19
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"'
associated degradation products may impact ground water quality as
well. The semi-volatile compounds phenol, benzoic acid and
phthalates were detected in on-site wells.
The metals arsenic, cadmium, and selenium were measured in levels
exceeding MCLs, and very high concentrations of molybden~m were
observed in on-site and off-site well samples.
Data submitted by the City and County of Denver, and confirmed by
CDH, indicate that ground water associated with the site is
infiltrating a storm sewer located along South Santa Fe Drive. The
storm sewer discharges into the South Platte river just south of .
Louisiana Avenue (figure 5-4). Data for samples obtained from
manhole 23A and the storm sewer outfall show elevated levels of
ammonia, molybdenum, copper, and uranium.
At the time CDH sampled, the manhole upgradient (south) of manhole.
23A was dry, indicating the water sampled in manhole 23A was
infiltrating the storm sewer at a. point between the. manholes.
Contours on the potentiometric surface measured in 1989 (figure 5-
2) indicate the portion of the storm sewer into which ground water
is infiltrating is located downgradient of the site. .
Data for well SHB-3 show elevated levels of ammonia, molybdenum,
. copper, and uranium. The SHB-3 data is generally higher than the
data for the manhole, indicating some dilution occurs between SHB-3
and the storm sewer.
6.0
SUMMARY OF SITE RISKS
A baseline risk assessment was conducted as part of the remedial
investigationifeasibility study to characterize the current or
potential threat to human health and the environment that may be .
posed by the contamination on the si~e.
The principal health threat posed by the site is carcinogenic risk
related to radium-226 contaminated soils. Risk estimates were
calculated based on the concentration of contamination found on the
site. The potential pathways of exposure evaluated in the baseline
risk assessment include future residential or occupational use of
the site based on the past and present use of the site and
surrounding area and the site's location within a large
metropolitan area. Exposure durations are evaluated in conjunction
with the contamination identified at the site to calculate the
baseline risk values. The following potential exposure pathways
have been evaluated:
20
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NOT TO SCALE
-O\IEJU.ANO GOLF CQuRSC:-
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Figure 5-4 StOJ:m Sewer Sampling I.ccations
- - .- -. -" " -... -- - . -- I -
;DENVER RADIUM I
OPERABLE UNIT VIII -
- !
" STORM. SEWER INVEST1GA TION
. SAMPLING LOCATIONS
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21
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o
inhalation of radon, particulate, and
direct exposure to gamma radiation; "
ingestion of contaminated soil;
ingestion of ground water; and
ingestion of garden produce grown in
organic compounds;
coritaminated soil.
In risk characterization, carcinogenic risk is presented" in the
form of a probability (i.e. the increased chance of contracting
cancer over a lifetime attributable to the site). As required by
the NCP, the risk range of one in ten thousand to one" in one
million (104 to 10~) is used as the range to indicate whether or
not an unacceptable risk is posed by the site. For non-
carcinogenic compounds, hazard quotients are calculated by
comparing a reference dose (Rfd), which is a dose for which there
is a potential for adverse health effects, to the estimated
potential dose for a given pathway of exposure. The hazard
quotients for a potential pathway of exposure are summed to obtain
a hazard index. A hazard index greater than one poses unacceptable
risk.
6.1
HUMAN HEALTH RISKS
6.1.1
Principal threats posed bv the site
The two major contaminants of concern for radiological exposure are
radon gas and gamma radiation, both of which are attributable to
the radium-contaminated soil located on the site. Radon gas is a
decay product of radium. Radon gas migrates from contaminated soil
into the atmosphere. The risks associated with radon gas arise
from inhalation of its short-lived decay products which can expose
the internal tissue of the lungs to bursts of energy if they decay
within the lungs.
Prolonged inhalation of air with a high concentration of radon
decay products has been conclusively shown to increase the risk of
contracting lung cancer in uranium miners. When radon gas emanates
from radium-contaminated soil, dispersion into the air generally
dilutes the radon. In open spaces, such dispersion usually reduces
radon concentrations to the extent that outdoor risks of radon
exposure are insignificant. However, radon decay products can
accumulate to unacceptable concentrations in buildings built over
contamination, because structures tend to trap radon gas.
The radioactive decay of radium and its decay products also results
in the emission of highly penetrating gamma radiation. Gamma
radiation is continuously emitted from radiologically-contaminated
soil. Gamma radiation is emitted in all directions from a source,
and exposure is dependent on proximity to the source and whether or "
not physical materials shield the source. Gamma radiation emitted
by unshielded radium-containing soil penetrates the soil to give
anyone standing over a contaminated area a radiation dose over the
22
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-
~
"
,',
..
t4
,-'
, ,
..j
:.;;
'"'
~'!i
, .
'.,
whole body. The greater the duration and intensi ty of this
exposure, the larger the dose, and hence the greater the risk of
adverse health effects. '
Radon
Seasonally corrected interior radon concentrations of 0.12 working
levels were observed on the Shattuck property. These
concentrations correspond to a 5 X 10~ lifetime cancer risk to a
future resident for a 30-year exposure or a 1 X 10~ lifetime cancer
risk to a future worker with a 20-year exposure. '
Dispersion modelling was used to estimate the off -si te radon
concentration attributable to the site. The results indicate that
the contribution of the Shattuck property to off-site radon
concentrations is negligible, with levels calculated as 0.00023
working levels for the 1800 block of South Acoma modelled as the
nearest residential area, and 0.008 working levels immediately
north of the Shattuck property, modelled as the nearest off-site
worker location.
Gamma Radiation
The projected lifetime cancer risk from gamma radiation to an
individual working 75% indoors and 25% outdoors on the Shattuck
property for 20 years is 1 X 10~. The calculated lifetime cancer
risk from gamma radiation exposure for the future residential
scenario on the Shattuck property is 5.6 X 10~, based on a 30-year
exposure and ~-he average one-meter gamma radiation measurements in
the vicinity of ~~e process buildings.
The risks calculated for radon inhalation and gamma radiation are
independent of each other. Hence the total risk potentially posed
by radium-contaminated soil is the sum of the radon and gamma
risks.
The risks represented herein are the calculated risks attributable
to the site. For comparison, the background gamma risk, based on
gamma measurements taken at the Overland Park Golf Course are 1.2
X 10~ for the future on-site residential scenario and 1.9 X 104 for
the future on-site worker scenario. A background risk for indoor
radon was not calculated. Indoor levels for radon can vary widely,
depending on natural soils as well as the physical aspects of a
building. '
23
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6.1.2
Additional Risks
The lifetime risk of cancer based on inhalation of airborne
, radioactive particulates was calculated as 4.4 X 10~ for future on-
site workers with a 20-year exposure. This risk was calculated
using air modelling of potential particulate concentrations based
on contaminant concentrations in surface soil. Air dispersion
modelling was used to calculate a lifetime cancer risk of 2.9 X 10~
for off-site residents, with a 30-year exposure based upon
contaminant concentrations in surface soils.
Inadvertent ingestion of soil was also evaluated. The sum of the
lifetime cancer risks for radium-226, thorium-230, lead-210 and
uranium results in a risk of 1. 7 X 10.5 for a 30-year on-site
residential setting, and 1.7 X10~ for a 20-year future on-site
worker scenario.
Ground water ingestion was evaluated to estimate risk if ground
water from beneath the site were utilized as a drinking water
source. For radioacti ve contaminants, uranium was the. most
si~nificant contributor, with a calculated lifetime risk of 6.7 X
10. based on drinking two liters of water per day for 30 years.
Calculations for non-radioactive contaminants indicate that arsenic
is the carcinogen of highest concern, with a lifetime risk of 2.7
X 104, while the lifetime risks from other carcinogens are below 1
X 10~. The non-carcinogenic contaminants molybdenum and antimony
are of concern with hazard indices of 160 and 5 respectively. The
ground water is not currently utilized as a drinking water source.
Therefore, there is no present exposure occurring via this roedium.
Ingestion of garden vegetables grown in contaminated soil was
evaluated using soil contaminant concentrations which exist on a
residential vicinity property. utilizing the assumption that 40
percent of an individual's annual vegetable intake is home grown,
the increased lifetime risk of contracting cancer due to vegetable
consumption was calculated to be 6 X 10~ for one year of
consumption and 1.9 X 104 for thirty years .of consumption.
Data collected during the remedial investigation indicate a number
of volatile organic compounds, including common industrial
solvents, have contaminated soils on the site. Evaluation of
potential inhalation of organic compounds indicated that this
pathway for exposure poses some risk to human. health with risk
factors calculated at 4 X 104 for the future on-site residential
scenario and 9.7 X 10~ for the off-site residential exposure based
on a 30-year exposure period.
Tables 6-1, 6-2, and 6-3 summarize the baseline radiologic risk,
hazard quotients, and non-radiologic cancer risks.
24
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Table 6-1
Summary of Radialion Risks
N
VI
I{eceptor Scenario Tolal Risk Background Sile Risk
Offsilc Gamma 1.8 x 10')
Rcsidcnts 1.1 x 10-1
Rudon .
ThoriulI\.Dust 2.8 x 10.8 2.8 X 10,8
Lcad-Dust 6.5 x 10.10 6.5 X 10,10
Radium,Dust 8.0 x 10'\1 8.0 X 10,12
Uranium,Dust J.8 x 10.10 1.8 X lO'tO
Onsite
Workers 1.2 x 10') 1.9 X 10'"' 1.0 X 10')
Gumma
Radon 1.0 x 10') .
ThoriulI\-Dust 4.3 x 10'1 4.3 X 10'1
Lead-Dust 3.6 x 10.9 3.6 X 10,9
Radium-Dust \.3 x 10.10 1.3 X 10,10
Uranium.DlIst 2.8 It 10.9 2.8 X 10.9
ThoriulII.soil ingcsliun 4.3 It 10,6 2.7 It 10,1 4:0 x 10-6
Lead,soil ingeslion 8.5 It 10'6 1.7 It 10,1 8,3 X 10-6
!tmliul\1.suil ingestion 2.3 It I ()'6 5 X 10'8 2.2 X 10-6
;. Uranium,soil ingeslion 2,0 It 10'6 1.3 It 10'8 2.0 X 10-6
TOTAL:: 1.0 x 10') (except radon)
-------
1-.)
m
~I/il) - .
I J{~ccr1or 'TIIIUlltbk L lI~ckgllllulll I Silu Iti~k I
FUIIllt:
II &:I;hlcub Idl . III) 1.2. III) ~.6 . III')
CI UIIIIIIII
Hullun s.n 1 IU'J .
ItlilliulII.J)rinklns Wllicr 5.23 . IO'} 5.2] . III'} 0
Thorillm.l)rlnkln. Waler 2.34 1 II)'} . 2.34 1 10.1
Uranium-Drink in. Waler 8.0 1 10" 1.3 1 10" 6.1 II 10"
Thoriuin.Soil 4.3'1 106 2.1 1 10.1 4.0 II 10"
l.ellll.5l1il 9.0 1 1U'6 1.1 X IO'} 8.8 1 10"
-
It IIlIiulII-Soll 2.4 x Ifl" S . 10' 2.3 1 10'6
UraniulII.Soil 2.0 1 Ifl" I.] x 10' 2.0 1 10.6
TOTAL.. S.7 1 10') (ellcepl radon)
-
Ofhile Workerl Thorlum.()uS! 2.7 II 10'1 2.1 II 10.1
l.ead,Pusl 2.2 1 Ifl" 2.2 II 10"
-
ltadillln,Pulil 8.0 1 10,11 8.0 II 10.11
Uranium.Pust 1.8 II 10" 1.8 II 10'"
-
TOTAL:: 2.1 II IO'}
Trupassers Galllllla 2.1 II 10" 4 II 10'6 1.8 II 10"
--
ThoriuIII,Dust 9.0 II 10' 9.01 10"
Leall.Dusl 1.5 I 111'" 1.S II 10.11
Itlldilllll.DuSI 2.8 I lO'u 2.8 I 10'u
Uraniul11.Dust 6.0 x ifI'" 6.0 1 10.11
Thnrill/ll-5oillnBclillnn 3.) . W'} 2.1 x 1(}.8 3.1 X IO'}
I.&:UII'SIlIl ingclilion 6.5 II IO'} IJ x 10' 6.4 X IO'}
Ihdilllll.lioil inBeilinn 1.8 x IO'} 4,0 xl/I' 1.8 x IO'}
Urunilll11'$oil inCcslion 2.9 x IO'} 1.5 x 10' 2.9 X IO'}
T()TAI" 14) X IllS
Table 6 1 (Cant)
-------
Table 6-2
Ilazard Quulienls (or Melals. vac's and Scmi.volalile Compounds
N
"
Chemical RID Hazard qllotienl
Inhalaliun Oral \Vorker on Residenl on Residenl on lhe Shalluck properly Worker on Treapaaser on ShaUuck
Ihe Ihe o(raile the o(falle property.
Shaltuck properly property
propc rl y (inhalaUon) Inhalotion Soil Ground {lnhalaUon) InhalaUon Soil
(inhalolion) ingeallon woler Ingestion
Ingeation
METAlS
Anlimony 4E.04 4.8
Areenic lE.03 8.9E.02 1.6E.l 7.6E.02
Barium lE.04 7E.02 2.3E.05 4.1E.06 3.2E.05 1.1 E.03 1.7E.02 2.8E.06
Cadmium 6E.04 1.6E.02 1.3E.02
Chromium 7E-03 6E-Q3 4.OE.09 4.9E.IO 6.8E.09 2.2E.04 7.3E.o9 2.0E.09 1.8E.04
Mercury 3E.04 3E-04 1.9E.06 3.7E.09 2.7E.08 7.0£.03 1.9E-02 2.6E.09
Molybdenum 3E.1I3 17 160 14
Nickel 2E.1I2 I.4E.03 6.0E-02
- -
Selenium 3E.1I3 6.0E.02 1.5E.Ol
'1.111<' :n:,11 !IIII':.II.1
.-.-.. . d. ---. .. - -.-_. .-.-. .---_w.-... ... --...- -....... - .. '.- .-. ~....-.,..; --. -
---
vue'S
Chlorofurm I E.1I2 2.0E.02 8.6E.03 1.6E.03
Melhylene chloride IIISE.III 6E.1I2 UII::.03 1.1 1::.(1.1 6.4E.03 2.8E.03 1.2E-02 3.8E.06 9.3E.04 1.1E.02
Toluene' 7E.IIII 21::.111 4.IIE.1I3 2.61::.114 1.2E.1I2 9.1E.05 2.0E-03 . 2.9£.03
. u
Scml.Vololilce
Bis(2. 2E-1I2 1.11::.04
(elhylhcxyllphlhololc
Phenol 6[.111 3.6E.07 6.2£.04
-------
Table 6-3
Summary of Aggreg31e Canc.e: Risks
I Route I Scenario leancerrisk! Comments \
0nsi1e worbn 9.1E-OS VOC- s. conaibute greatest risk
FU!UrC onsitc residents 4.oE-04 vex:: s conaibute greatest risk
Inhalation Offsitc workers 2..2E~ VOC-s contribute greatest risk
Offsitc residents 9.1E~ VOC's contribute greatest risk
Trespassers 2.1E~ VOC's contribute greatest risk
GroundW:1tcr Future onsite residents 2.1E-04 Arsenic contributes greatest risk
ingestion
Onsite workers 2.2E-OS .~ic: conlributcs grc:1test risk
Onsite residents 7.2E-OS .~c: contributes gratest risk I
Soil ingestion Tresp:1Sscrs 8.4E~ I .~c: contributes grc:1tcst rislc I
28-
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Conclusion
As noted in the text and the tables, potential cancer risks for
several contaminants exceed the acceptable risk range of 104 to 10~
and non-carcinogenic risks for several contaminants exceed a hazard
quotient of one. Actual or threatened releases of hazardous
substances from this site, if not addressed by implementing the
,response-action selected in this record of decision, may pose an
imminent and substantial endangerment to public health, welfare, or
the environment. '
6.2
ENVIRONMENTAL RISKS
Risks to the natural environment were initially considered in the
remedial investigation. No threatened or endangered species were
observed during the remedial investigation field work performed in
1989. The wildlife and fauna observed were typical to the Denver
metropolitan area. Ground water modelling indicated that impacts
on the South Platte River from the site, while contributing to the
contaminant loading of the river system, are so dilute by the time
of impact that effect on the river ecosystem is negligible. No
further investigation of environmental risk was conducted.
7.0
DESCRIPTION OF ALTERNATIVES
A feasibility study was conducted to evaluate remedial action
alternatives for the Denver Radium, Operable unit VIII, site. The
remedial alternatives were evaluated in accordance with CERCLA, as
amended by SARA, and to the extent practicable, the NCP. A broad
range of response actions and technologies was initially considered
and screened based on relative effectiveness, implementability, and
cost. The technology screening was used to develop a limited
number of alternatives which focus on technologies showing the most
promise and covering an appropriate range in methodology. The
. range of alternatives dev'eloped for a detailed analysis and
comparison included: on-site control or containment; treatment;
off-site disposal; and combinations of technologies. In addition
to remedial alternatives, the NCP requires a no action alternative
be considered at every site. The no action alternative serves
primarily as a point of comparison for the other alternatives.
As described in the feasibility study, remedial action objectives
were identified on the basis of the site characterization results.
A brief discussion of the primary applicable or relevant and
appropriate requirements (ARARs) related to each alternative is
included in the description of alternatives contained in section
7.2.
29
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7 . 1. . SCREENING
During screening, technologies were considered for the media of
soils, facilities, and ground water. . .
Ground wa ter:
control, and
technologies.
Potentially viable technologies and process options were then
combined into site-wide alternatives for a .more detailed
evaluation. Cross media considerations. utilized in developing
site-wide alternatives resulted in additional narrowing of the
technologies for facilities and ground water as detailed below:
o
o
. 0
Soils: Screening identified capping, in-situ treatment, -
excavation. and treatment, disposal off-site, and
combinations of these technologies as potentially viable
technologies. ..
Facilities: Screening identified shielding, sealants,
passive collection, active collection, decontamination,
and demolition and disposal as potentially viable
technologies.
o
Screening identified barriers,
treatment as potentially
source
viable
Facilities - The technologies considered for remediation of
the facilities located on the Shattuck property focused on
those which included removal of the facilities because
remediation of the soil is easier and more effective with the
facilities removed. The technologies consistent with. removal
of the facilities include demolition and disposal, or reuse.
Since some of the facilities are radiologically-contaminated,
the ability to decontaminate or clean building materials. prior
to disposal was evaluated.
Ground water During the development .of alternatives,
treatment of ground water was screened out. Alternatives then
focused on source control in conjunction with monitoring, with
further action in the future, if necessary. This approach was
based. on the information collected during the remedial
investigation which indicated:
o
There are no current uses of ground water impacted by the
site.
The extent of the contamination is limited, and potential
for use is minimal in the short-term.
Groundwater contamination appears to be decreasing over
time.
Remedies which remove or immobilize the source are
expected to accelerate improvement in ground water
quality.
o
o
30
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The decision to focus on source control as a remedy for ground
water contamination is reasonable for the circumstances of
this site. Source control is expected to result in long-term
protection and attainment of remedial action objectives.
If monitoring shows that attenuation is not adequately
protective of human health and the environment, additional
remediation would be initiated at a future date. The remedial
action standards for ground water, which will be utilized to
assess the effectiveness of attenuation, are the Safe Drinking
Water Act MCLs, state ground water standards, and proposed 40
CFR. 192 standards (See the chemical-specific state and
federal ARARs for ground water, table 3, in appendix A).
As a result of the. screening process, seven remedial
alternatives were developed for detailed analysis.
action
7.2
SUMMARY OF ALTERNATIVES
The alternatives presented in. the feasibility study report are
summarized below. The alternatives are:
8Alternative I
No Action
8Alternative III
Restrict site access, excavate railroad and
vicinity properties
Cap site with clean soil
8Alternative II
8Alternative IV
In-situ vitrification
8Alternative VI
Excavation, stabilization, on-site disposal
Excavate, remove and replace all contaminated
soil
8Alternative V
8Alternative VII
Excavate,
soils
physical/chemical
treatment
of
The proposed plan identified Alternative VI, excavate and replace,
as the preferred alternative. Alternative V, stabilization, was
also identified in the proposed plan and feasibility study as a
potentially viable and adequately protective alternative. Based on
consideration of public comments, new cost information, and the
remedy selection criteria, CDH and EFA have selected Alternative V,
stabilization, for cleanup of the Denver Radium site, Operable unit
VIII. A detailed discussion of the changes from the proposed plan
is contained in section 9.3.
31
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7.2.1.
Common Elements:
Railroad and vicinitv DroDerties:
All alternatives (except no action) include excavation of the
contaminated soils on the railroad rights-of-way and the vicinity
properties. In Alternative II, the contaminated materials from the
railroad property would be plac~d on the Shattuck property, while
the contaminated materials from the vicinity properties would be
disposed of at an off-site facility. In Alternatives III through
VII, the contaminated materials from the railroad properties and
the vicinity properties would be placed on the Shattuck property
and managed in the same manner as the materials on the Shattuck
property.
EPA and CDH will evaluate the use of supplemental standards beneath
the rail lines and South Bannock Street during remedial design.
Supplemental standards are. a part of the 40 CPR 192 regulations
which are ARARs for the site. They allow leaving contamination in
place under specified conditions. When evaluating the
applicability of supplemental standards, EPA and CDH are required
to select remedial actions that come as close to meeting the
otherwise applicable standard as is reasonable under the
circumstances.
Facilities:
Alternatives III through VII include demolition and disposal of all
the buildings, equipment and facilities on the Shattuck property
prior to remediaticn of the soils. This step is considered
necessary because of the contamination of the facilities and the
need to remove the facilities in order to implement the remedial
actions. Treatability studies of .facility decontamination were
performed to evaluate the ability to physically remove radioactive
contamination from building materials. The methods employed
included brushing, washing, abrasion, and planing techniques. The
materials tested included painted metal, painted wood, concrete,
brick and cinderblock. The test results indicated that moderately
contaminated facilities could be successfully cleaned while more
heavily contaminated surfaces probably could not be adequately.
decontaminated. It i~ anticipated that materials associated with
buildings 5 and 6 (identified in the FS), as well as contaminated
tanks and equipment can be effectively decontaminated. Cost
estimates for disposal of the facilities are based on disposal of
the radioactive materials associated with the facilities at a low
level radioactive waste disposal site in Nevada, and disposal of
solid wastes, including asbestos, locally.
32
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,:
'.
On-site alternatives:
With Alternatives I, II, III, IV, or V, radioactive materials would
remain on site, and the site would be controlled in the future,
thus limiting future land use.
Alternatives invo1vina excavation:
The excavation of contaminated soils would be based on health-based
action levels. The action levels are derived from the risk
assessment, health-based standards set out in regulations, and
other requirements. .
The radioactive contamination of the soils is predominantly in the
fine particles. Treatability studies of physical separation were
conducted to test the technical feasibility of screening the soils
to reduce the volume of radioactive soils. The results obtained by
both CDH and Shattuck indicate a significant volume reduction may
be technically feasible. Screening separates the soils into coarse
particles and fine particles. The studies showed that for some of
the contaminated soils, wet screening separates .the contaminants
such that only the fine particles require management as
contaminated materials, thereby reducing the volume of contaminated
materials. This technology can potentially be utilized with
Alternatives V, VI, and VII, each of which involve excavation of
contaminated soils. Since the treatability studies were. not.
extensive enough to definitively determine the overall cost,
effectiveness, and imp1ementabi1ity of screening, the potential
volume reduction that screening could account for was not factored.
into the alternatives.
. Storm Sewer:
The ground water which infiltrates the storm sewer located west of
the site along south Santa Fe Drive results in a point source
discharge into the South Platte River. Corrective acti,on as
required to comply with the Clean Water Act and Colorado Water
Quality Control regulations (5 CCR 1002-2 3.1, 3.8 & 6.1 et ~)
would be included under Alternatives II through VII. The means of
compliance could involve eliminating' the infiltration or treating
the discharge, and will be determined during remedial design. The
costs associated with remedial action for the storm sewer are not
included in the alternatives, but would be similar under each
alternative.
33
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7.2.2
Description of Alternatives:
Alternative I - No Action
capital Cost: $0 .
operation and Maintenance
TOTAL: $323,000
Time to implement: 0
(O&M) Cost: $323,000/5 years
The NCP requires that the "no action" alternative be evaluated at
every site to establish a baseline for comparison. Under this
alternative, no further action would be taken at the site to
prevent exposure to the contamination. No treatment or containment
of contaminants is envisioned under this alternative. ARARs
relating to the management of radiologically-contaminated soils
.would not be attained. . Ground water conditions would not change
except by attenuation. This alternative is not expected to attain
ARARs for ground water. Monitoring of fugitive dust emissions,
radioactivity, and ground water is included for five years to
verify conditions near the site.
Alternative II - Restrict
vicinity properties
site
access:
excavate railroad and
Capital.Cost: $3,900,000
Annual O&M Costs: $1.20,000.
PAV: $6,300,000 (PAV = Present Annuity Value = amount to fund
capital work plus that which must be invested now to
have funds available for future costs, such as operation
and maintenance. Annual future costs are discounted at
5% for 200 years. The term of 200 years was utilized
because of the nature of the materials and is consistent
with other situations addressing radioactive materials.
This same assumption was used for Alternatives III
through V.)
Time to implement: 1 month
ApproximatelY 5,000 cubic yards of contaminated soil would be
excavated from the railroad rights-of-way and placed on the
Shattuck property. Approximately 6,000 cubic yards of contaminated
soil from the vicinity properties would be removed and disposed of
at an off-site facility. Institutional controls such as deed
restrictions; would be permanently utilized along with security
fencing and monitoring to limit public exposure to contaminants and
monitor site conditions. Although the health risks posed by the
railroad and vicinity properties would be addressed, the health
risks posed by the Shattuck property would remain essentially
unchanged. No treatment or containment of the materials on the
Shattuck property. would occur. ARARs relating to the management of
radiologically-contaminated soils would not be attained. Ground
water conditions would not change except by attenuation. This
alternative is not expected to attain ARARs for ground water.
34
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Alternative III - Cap site with clean soil
capital Cost: $12,600,000
Annual O&M Costs: $120,000
PAV: $15,000,000
Time to implement: 9 months
This remedy involves clearing the facilities from the Shattuck
property. The estimated 38,500 cubic yards of contaminated soil on
the Shattuck property would be left in place. Approximately 11,000
cubic yards of contaminated soils from the railroad and vicinity
properties would be placed on the Shattuck property. A clay cap
covered by topsoil would be installed over the 5.9 acre Shattuck
property.
The cap would be designed and constructed to promote drainage,
minimize erosion of the cover, provide long-term minimization of
migration of liquids through the underlying contaminated soils, and
provide a shield from gamma radiation. consistent wi th the
requirements of 40 CFR 192 Subpart A, the cap would be required to
reduce radon emanation and achieve 1000 year permanence to the
extent practicable. The remedy as a whole would be designed to
attain a reduction in post-remedial risk consistent. with NCP
requirements. The performance standards of 6 CCR 1007-1 part
14.19-14.22 would be relevant and appropriate to this alternative.
Capping the contaminants on-site would rely heavily on
institutional controls to prevent future intrusion into the
contaminated soils. This would be necessary to assure long-tarm
effectiveness because the contaminated soils would net be treated.
The ability of this alternative to comply with 6 CCR 1007-1 part
14.19-14.22 requirements of long term isolation is uncertain
because of the potential for the contaminants to leach to ground
water. The cap would be vegetated or armored with rock to control
surface erosion. Since much of the site is currently covered by
asphalt, concrete, and structures, the cap might not result in a
significant reduction of infiltration, and it is uncertain whether
this alternative would lead to improvement in ground water quality.
Ground water monitoring consistent with 6 CCR 1007-1 part 14.26.3
and 40 CFR 192 regulations would be required. The health threat
posed by the site could potentially be acceptably reduced for
soils, but it is doubtful that the remedy would be adequately
protective for the ground water pathway.
Alternative IV - In-situ vitrification
Capital Cost: $35,900,000
Annual O&M Costs: $120,000
PAV: $38,300,000
Time to implement: 4 years
35
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This remedy involves clearing the facilities from the Shattuck
property. The estimated 11,000 cubic yards of contaminated soils
from the ra.ilroad rights-of-way and vicinity properties would be
placed on the Shattuck property. -A total of approximately 50,000
cubic yards of soil would be vitrified. vitrification involves
electrically melting the soil in place, leaving an essentially
impermeable, but still radioactive, d~posit.
A bench scale test of vitrification was conducted as part of the
remedial investigation/feasibility study. The test involved
vitrification of an 8" by 8" by 10" sample of contaminated soil.
Power was applied to electrodes surrounding the sample. . Over a
period of about six hours the sample soils melted. After cooling,
the mass assumed a glass-like structure which is effective at
immobilizing heavy metals and radioactive contaminants. Larger
scale pilot testing would be necessary prior to full scale
implementation in order to refine design parameters and as
additional verification of the implementability of the technology.
A compacted soil cap would be placed over the deposit to provide a
shield from gamma radiation. The cap would be designed and
constructed to promote drainage, minimize erosion of the cover, and
provide long-term minimization of migration of liquids through the
vitrified soil. consistent with the requirements of 40 CFR 192
Subpart A, vitrification of the contaminated soils would reduce
radon emanation to below the disposal standard of 20 pCi/m2/s and
the cap would be designed to achieve 1000 year permanence to the
extent practicable. The remedy as a whole would be designed to
att-ain a reduction in post-remedial ri~k consistent with NCP
requirements. The performance standards of 6 CCR 1007-1 part
14.19-14.22 would be relevant and appropriate to in-situ
vitrification. The nature of the vitrified mass would discourage
intrusion into the treated materials and reduce the potential that
the vitrified soil would be inadvertently used as fill material.
Institutional controls to prevent future intrusion into the treated
soils would be used to supplement the remedy and assure long-term
effectiveness. The cap would be vegetated or armored with rock to
control surface erosion. Ground water monitoring consistent with
6 CCR 1007-1 part 14.26.3 and 40 CFR 192 regulations would be used
to monitor the effectiveness of vitrification in immobilizing the
contaminants and providing source control. This alternative would
reduce the health threat posed by the site to an acceptable level.
Alternative V - stabilization
Capital Cost: $24,200,000
Annual O&M Costs: $120,000
PAV: $26,600,000
Time to implement: 15 months
36
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This alternative is the selected alternative. This remedy involves
clearing the facilities from the Shattuck property. The
contaminated soils from the entire site (estimated at 50,000 cubic
yards of soil from the - railroad. rights-of-way, the vicinity
properties, and the Shattuck property) would be excavated,
stabilized, placed on the Shattuck property, and capped.
Stabilization would be achieved using an on-site batch plant
operation to mix the soil with. cement or a similar material.
Treatability testing of stabilization was conducted by the Shattuck
Chemical Company. The tests consisted of mixing site soils with
differing amounts of cement, fly ash, and silica flour. The
mixtures consisted of 70 to 80 percent soil and 20 to 30 percent
cement and additives. The materials were cast into test cylinders.
Stabilization immobilized the contaminants, reduced radon emanation
and resulted in. a concrete-like stabilized mass. Larger scale
pilot testing would be necessary prior to full scale implementation
in order to refine design parameters and as additional verification
of the implementability of this technology. .
Stabilization results in a matrix which is similar to concrete.
Treatment reduces the permeability of the contaminated soils, and
provides chemical as well as physical protection. The gamma
radiation toxicity of the contaminated soils would decrease
somewhat with the addition of the cement.
A compacted soil cap would be placed over the stabilized materials
to provide a shield from gamma radiation. The cap would be.
designed and constructed to promote drainage, minimiza erosion of
the cover, and provide long-term minimization of migration of
liquids through -the stabilized soils. Bench scale treatability
tests indicate stabilization of the contaminated soils would reduce
radon emanation to below the 40 CFR 192 Subpart A disposal standard
of 20 pCi/m2/s. Consistent with the requirements of 40 CFR 192
Subpart A, the cap would be designed to achieve 1000 year
permanence to the extent practicable. The remedy as a whole would
be designed to attain a reduction in post-remedial risk consistent
with NCP requirements. The performance standards of 6 CCR 1007-1
part 14.19-14.22 would be relevant and appropriate to on-site
stabilization.
The physical nature of the stabilized soils would discourage
intrusion into the .treated materials and reduce the potential of
the contamination being inadvertently used as fill material.
Institutional controls to prevent future intrusion into the treated
soils would be used to supplement the remedy and assure long-term
effectiveness. The cap would be vegetated or armored with rock to
control surface erosion. Ground water monitoring consistent with
6 CCR 1007-1 part 14.26.3 and 40 CFR 192 regulations would be
required to monitor the effectiveness of stabilization in
immobilizing the contaminants and providing source control. This
37
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alternative would reduce the health threat posed by the site to an
acceptable level.
Alternative VI - Excavate. remove and reDlace all contaminated soil
capital Cost: $36,800,000 - 48,800,000
Annual O&M Costs: °
PAV: $36,800,000 - $48,800,000
Time to implement: 1 year
This remedy involves clearing the facilities from the Shattuck
property. The estimated 50,000 cubic yards of contaminated soil
would be excavated and disposed off site at a waste disposal site
permitted to accept the wastes and in compliance with EPA's off-
site policy (OSWER Directive 9834.~1). This remedy would attain
the 5 pCi/g and 15 pCi/g surface and subsurface standards of 40
CFR 192 Subpart B by excavating the contaminated materials for off-
site disposal. The excavated area would be backfilled with clean
soil. It is anticipated that the need for long-term monitoring and
maintenance would be eliminated. Ground water monitoring would be
required until attainment of ground water ARARs. This alternative
would reduce the health threat posed by the site to approximately
background level.
Alternative VII - physical/chemical treatment of soils
capital Cost: $43,300,000
Annual O&M Costs: $0
PAV: $43,300,000
Time to implement: 18 months
This remedy involves clearing the facilities from the Shattuck
property. The estimated 50,000 cubic yards of contaminated soil
would be excavated and processed on the Shatt.uck property in a
plant designed to remove contaminants to an acceptable level. The
decontaminated soils would be used to backfill the site, and the
concentrated contaminants would .be hauled to an appropriate waste
disposal site. This alternative involves a complex, but tested,
chemical processing scheme which has relatively high capital costs.
Treatability studies were performed during the remedial
investigation/feasibility study. The studies explored the
feasibility of utilizing chemical leaching schemes. to remove
radioactive contaminants from site soils. Chemical treatment was
demonstrated as a means which could remove the contaminants from
the soils, enabling the bulk of the contaminated soils to be placed
back on the site. The contaminants would be concentrated,
resulting in a smaller volume of higher toxicity materials, which
would be disposed of off-site.
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This remedy would attain the 5 pCi/g and 15 pCi/g surface and
subsurface standards of 40 CFR 192 Subpart B by removal of the
contaminants from the soils for off-site disposal. It. is
anticipated that the need for long-term monitoring and maintenance
would be eliminated. However, groundwater monitoring would be
required until attainment of ground water ARARs. This alternative
would reduce the health threat posed by the site to approximately
back~ound level.
8.0
COMPARATIVE ANALYSIS OF ALTERNATIVES
The following discussion summarizes the evaluation and comparison
of alternatives. The alternatives identified in the feasibility
study were evaluated utilizing the nine criteria set forth by the
NCP. These criteria are:
( 1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Overall protection of human health and environment.
Compliance with applicable or relevant
requirements (detailed in section 10.0).
appropriate
and
Long-term effectiveness and permanence in protecting human
health and the environment.
Reduction of toxicity, mobility,
contaminants through treatment.
volume
of
the
or
Short-term effectiveness in protecting human health and the
environment.
Implementability.
Cost.
Community acceptance.
state acceptance.
criteria 1 and 2 are threshold criteria which must be attained by
the selected remedial action. criteria 3, 4, 5, 6, and 7 are
balancing criteria. The final two criteria are modifying criteria.
8.1 EVALUATION OF ALTERNATIVES
8.1.1 Overall Protection of Human Health and the Environment
Overall protection of human health and the environment addresses
whether a remedy provides adequate protection and how risks posed
through each exposure pathway are eliminated,. reduced, or
controlled through treatment, engineering controls, or
institutional controls.
39
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, "
Al ternati ves IV through VII would
protection of human health and the
less certain whether Alternative
protectiveness.
all achieve adequate overall
environment. It is somewhat
III would achieve adequate
Alternative I, no action, would not be adequately protective.
Risks from all of the exposure pathways (see section 6.0 of this.
ROD) would remain at unacceptable levels. -
Alternative II, restrict access, would not be adequately
-protective. Risks at the vicinity properties and the railroad
rights-of way would be addressed by removing contaminated soils.
Risks .based on the contaminated soils at the Shattuck property
would not be adequately addressed, because the only measure which
would be taken would be restriction of access. No treatment or
containment would occur. In addition, contaminants could continue
to leach to ground water and health-based ground water ARARs would
not be met. '
Human Health:
Alternatives IV through VII would address all potential exposure
pathways: inhalation of radon, exposure to gamma radiation,
inhalation of particulates and organic compounds, ingestion of
contaminated soil, ingestion of produce grown in contaminated soil,
'and ingestion of contaminated ground water. The following is a
comparison of how these alternatives would address risks arising
from the exposure pathways. '
For Alternatives III through VII, the facilities on-site would be
demolished, and future construction would be limited for 'the
alternatives where waste is left on-site, thereby precluding the
buildup of indoor radon.
Alternative VI, excavate and replace, and Alternative VII,
chemical/physical, would be equally protective in addressing the
risks from all pathways. These two alternatives would remove the
,radium-contaminated soils from the site, thus eliminating the
source of radon precursors and particulates and organic compounds.
contaminants in the soil that could be ingested or serve as a
source of contaminant loading to the ground water would be removed
from the site, thus addressing the risks from the ingestion
pathways.
Alternative IV, vitrification, and Alternative V, stabilization
would effectively reduce exposure to gamma radiation and reduce
exposure through the inhalation pathway for radon to acceptable
levels in the following ways:
40
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o
the contaminated soils would be vitrified or stabilized
which would diminish radon emanation from the soils and
slightly reduce the emission of gamma radiation;
following on-site disposal, the treated soils wquld be
capped which would further reduce radon emanation and
shield gamma radiation emitted from the soils;
o
o
institutional controls would limit future construction
of buildings, land use at the site, and intrusion into
the treated soils.
Exposure to particulates and organic compounds through the
inhalation pathway would be reduced to acceptable levels for.
Alternative IV, vitrification, and Alternative V, stabilization,
through the treatment processes involved, isolation of the soils
beneath a cap, and ins~itutional controls.
For Alternative IV, vitrification, and. Alternative V,
stabilization, ingestion of contaminated soils would be eliminated
through capping and institutional controls. The treated form of
the soils would also inhibit ingestion. .
Alternative IV, vitrification, and Alternative V, stabilization,
would eliminate the pathway of ingestion of garden produce grown in
contaminated soil through excavation, treatment, and isolation of
the contaminated soils. The solidified form of the soils would
discourage inadvertent use of the treated soils and institutional
controls would provide additional assurance that the treated soils
would not be removed or used. .
The contaminated ground water currently does not pose a threat and
is diluted prior to reaching the Platte River. However, the ground
water contamination could pose a health risk if it were to be used
as drinking water in the future. controlling the source of ground
water contamination would reduce and over time eliminate the
potential health threat as the. ground water contamination
attenuates or flushes. Alternative IV, vitrification, and
Alternative V, stabilization, would address the pathway of
ingestion of contaminated ground water by source control. The
contaminated soils at the site would be vitrified or stabilized,
immobilizing the contaminants and limiting the loading to the
ground water. Coordination with property owners downgradient of
the site, including surveys of downgradient ground water use would
be pursued, to ensure that ground water is not used for dri~ing.
Alternative III, cap site, would limit exposure to radon and
particulates and organic compounds through the inhalation pathway,
would reduce exposure to gamma radiation , and would reduce the
potential for ingestion of contaminated soil and produce grown in
41
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contaminated .soil, by capping the contaminated soils. The
protectiveness of this remedy is less certain than for Alternatives
IV through VII because the contaminated soil would be left on-site
untreated. There would be a greater reliance on the integrity of
the cap and institutional cont~ols.
The ability of ground water contamination to attenuate is uncertain"
for Alternative III, cap site, because contaminated soils could
continue to act as a source of contamination. capping may reduce
the infiltration of water into the contaminated soils, thereby
reducing the migration of the contaminants into the ground water.
However, since much of the site is currently covered by ~sphalt,
concrete, and structures, the cap may not result in a significant
reduction of infiltration, and it is uncertain whether this
alternative would lead to a significant improvement in ground water
quality over time. If improvement in ground water quality were to
occur under this alternative, it would take longer than for
Alternatives IV through VII. -
Alternative VI, excavate and replace, and Alternative .VII,
physical/chemical, would provide the -most protection of human
health by eliminating all of the exposure pathways of concern by
removing the contamination. Alternative- IV, vitrification, and
Alternative V, stabilization, which provide for on-site disposal,
would also provide adequate protection of human health by use of
treatment, engineered containment, and institutional controls to
eliminate and/or control the pathways of concern. The
protectiveness of Alternative III is less certain, particularly
with regard to its reliance on institutional controls, and the
potential ingestion of contaminated ground water.
Environment:
Relative to environmental protection (such as wildlife, fisheries,
etc.), no hazards or degradation to the environment have been
identified as baseline or remediation risks; The potential impact
. of the infiltration to the storm sewer and subsequent discharge to
the South Platte River will be addressed by treatment or
elimination of the infiltration under any of the alternatives.
8.1.2 Compliance with Applicable or Relevant
Reauirements (ARARs)
and Appropriate
compliance with applicable or relevant and appropriate requirements
(ARARS) addresses whether or not a remedy would meet all federal
and state environmental laws and regulations (or provides grounds
for invoking a waiver).
Alternatives IV, V, VI, and VII would all attain ARARs.
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40 CFR 192 Subpart B is the primary ARAR where soils will be
excavated and removed. The primary ARARs for on-site disposal are
40 CFR 192 Subpart A and 6 CCR 1007-1 Part 14.19-14.22. On-site
disposal would be designed to attain a 1000-year permanence to the
extent practicable, and in any event 200 years, as required by 40
CFR 192 Subpart A. The ARARs and other regulations to be
considered (TBCs) for ground water, which will be utilized to
assess the effectiveness of attenuation, are the Safe Drinking
Water Act MCLs, state ground " water standards, and proposed 40 CFR
192 standards. (See the contaminant-specific state and federal
ARARs for ground water, table 3, in appendix A).
Alternatives III through VII would attain soil-based ARARs at the
railroad rights-of-way and the vicinity properties by excavating
soils contaminated at levels in excess of the 40 CFR 192 Subpart B
standards. (EPA and CDH will evaluate the use of 40 CFR 192
Subpart C supplement.al standards for the rail lines and South
Bannock Street. These standards allow leaving contaminated soils
in place under specified conditions.) Alternatives IV through VII
are expected to attain ground water ARARs-, because -source materials
would be either removed or treated to reduce their mobility
limiting the loading of contamination into the ground water.
Alternative VI, excavate and replace, and Alternative VII,
physical! chemical, would meet 40 CFR 192 Subpart B standards by
excavating any soils exceeding the standards and disposing them
off-site. Disposal of the soils, or treatment residue in the case
of Alternative VII, would comply with EPA's off-site policy (OSWER
Directive 9834.11). Ground water monitoring for these alternatives
could be discontinued after the contaminated ground water
attenuates to ARARs.
Alternative IV, vitrification, and Alternative V, .stabilization,
would attain the standards of 40 CFR 192 Subpart A on the Shattuck
property by consolidating, treating, and capping the contaminated
soils to immobilize the contaminants and reduce radon emanation.
The performance requirements of 6 CCR 1007-1 Part 14.19-14.22 would
be relevant and appropriate to on-site disposal. Monitoring,
maintenance, and institutional controls would allow the on-site
disposal alternatives to meet the substantive requirements of 6 CCR
1007-1 Part 14. Compliance with these requirements would be
verified prior to implementation and would have to be demonstrated
by the remedial action design. Ground water monitoring near the
disposed materials would be continued over the long-term to assure
that contaminants remain bound in the treatment matrix.
Alternative III, cap site, would attain the soil-based ARARson the
Shattuck property by consolidating and covering the contamlnated
soils with a-cap designed to meet the performance standards for
radon emanation and permanence of 40 CFR 192 Subpart A. However,
capping alone would rely heavily on institutional controls. Ground
water monitoring near the disposed materials would be continued
43
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over the long-term to evaluate whether capping adequately controls
the source materials. capping the site could lead. to some
improvement in existing ground water quality, but the improvement
is not expected to be as effective as for Alternatives IV through
VII because the contaminants would not be immobilized or removed.
Alternative I, no action, and Alternative II, restrict access,
would not attain the soil-based ARARs of 40 CFR 192 subparts A or
B. Alternative I, no action, would take no action with regard to
contaminated soils. Alternative II, restrict access, would attain
40 CFR 192 subpart B requirements for the railroad rights-of-way
and the vicinity properties. However , it would not meet the
requirements of 40 CFR 192 subparts A or B for the contaminated
soil located on the Shattuck property. Alternative I, no action,
and Alternative II, restrict access, are not expected to attain
ground water ARARs. The source materials would remain in their
current state and could continue to impact ground water.
Because Alternative I, no. action, and Alternative II, restrict
access, would not attain the threshold requirements of overall
protection of human health and the environment and compliance with
ARARs, they are not discussed in detail wi th regard to the
remaining criteria. Alternative III, cap .site, would attain ARARs
for soils, but it is uncertain whether it would attain ground water
ARARs. Alternatives IV through VII would attain the threshold
requirements of overall protection of human health and the
environment and compliance with ARARs.
8.1.3 Lona-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to the magnitude of
residual risk and the ability of a remedy to maintain reliable
protection of hwnan heal th and the environment over time once
cleanup goals have been met.
Alternative VI, excavate and replace, and Alternative VII,
physical/chemical, would provide the best long-term effectiveness
and permanence for the site, since the contaminants would be
removed from the si~e. Removal of contaminants from the site would
reduce risks at the site to approximately background levels. It is
expected that ground water monitoring and reviews would be
discontinued after ground water ARARs are attained.
Alternative IV, vitrification, and Alternative V, stabilization,
would each achieve long-term effectiveness and permanence by
immobilizing the soil contaminants, reducing radon emanation, and
. shielding gamma radiation. The treated waste form and 1;.he cap
would isolate the radioactive materials and prevent inadvertent
intrusion. Monitoring, maintenance, and institutional controls
would enhance the long-term effectiveness and permanence of these
alternatives by assuring the continued isolation of the treated
materials. Where contaminants remain on site, CERCLA requires that
44
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the site be reviewed at least every five years to ensure protection
of human' health. Therefore, ground' water monitoring near the
disposal unit and five year reviews would be continued in the
future, even after ARARs are attained.
stabilization would result in a mass which is similar to concrete
and would reduce the permeability of and radon emanation from the
contaminated soil. ~tructural concrete encapsulation has been
utilized as a component in the management of higher level
radioactive wastes, and cement-soil mixtures are commonly used for
the stabilization of inorganic materials. Treatability studies
performed on soil obtained from the site indicate stabilization can
achieve long-term effectiveness and permanence.
Vitrification results in a glass-like matrix which also reduces the
permeability of. and radon emanation from the contaminated soil.
vitrification is anticipated to be permanent.
Alternative III, cap site, is the least reliable of .the
alternatives. Failure or breach of the cap is of greater concern
for Alternative III, cap site, than for Alternatives IV,
vitrification, or v, stabilization, because the underlying wastes
would be in an untreated form. In addition, the untreated
contaminated soils beneath the cap could continue to leach
contaminants into the ground water. The effecti veness of the
source control provided by capping alone is uncertain. Ground
water contamination could potentially pose a health threat in the
future if the untreated contaminated soils continue to act as a
source of contamination and the ground water were used as drinking
water. since wastes would remain on-site, CERCLA would require
that the site be reviewed at least every five years to ensure
protection of human health. .
For Alternative III, cap site, Alternative IV, vitrification, and
Alternative V, stabilization, evaluation of the monitoring data
would determine whether ground water quality was improving
adequately or whether active restoration measures would be
warranted. Ground water monitoring near the disposal unit and five
year reviews would continue in the future even if ARARs were
attained.
Alternative VI, excavate and replace, or Alternative VII,
physical/chemical would provide the best remedy in terms of long-
term effectiveness and permanence since contaminated materials
would be disposed off-site. Alternative IV, in-situ vitrification~
and Alternative V, stabilization, each would achieve long-term
effectiveness and permanence by using treatment technologies in
conjunction with capping and institutional controls. Alternative
III, cap site, would be the least effective since contaminated
soils would be left untreated and the soils could continue to leach
contaminants into ground water.
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8.1.4
Reduction of Toxicitv. Mobilitv or Volume throuqh Treatment
Reduction of toxicity, mobility, or volume through treatment is the
anticipated performance of the treatment technologies that may be
employed in a remedy. CERCLA contains a statutory preference for
on-site remedies which include a treatment component.
Alternative IV, in-situ vitrification, and Alternative V,
stabilization, would satisfy the statutory preference since each is
an on-site remedy which uses a treatment technology to immobilize
the contaminants. The benefit of immobilization is a reduction in
the number of pathways by which the radioactive contaminants can
pose a health threat. Stabilization and vitrification would reduce
the potential for disperston of contaminants in dust particulates,
would reduce the radon threat by limiting radon emissions, would
.reduce the leachability of contaminants to ground water, and would
discourage intrusion into the treated materials. The radioactive
nature of the contaminants is not a "treatable II characteristic, and
the immobilized materials would continue to require management as
radioactive material because they would continue to exhibit gamma
radioactivity. While both alternatives would reduce the mobility
of the contaminants, in-situ vitrification would also reduce the
volume of contaminated soils by. approximately 25%, while
stabilization, due to the addition of. cement to the soil, would
increase the volume of the contaminated soils. Since mobility is
reduced through stabilization, this increase in volume is not
significant from a risk standpoint.
Alternative VII, physical/chemical, utilizes chemical treatment to
separate the contaminants from L~e soil. While this technology
would reduce the volume of the contaminated soil, the resultant
product would be higher in toxicity and would need to be disposed
off-site.
Alternative III, cap site, and Alternative VI, excavate and
replace, would not attain the statutory preference to utilize
treatment as a central component to reduce the toxicity, mobility
or volume of the contaminated soils. In neither case would the
chemical and physical characteristics of the soils be changed.
Alternative III, cap site, would leave untreated soils on-site.
Alternative VI, excavate and replace, would require untreated soil
to be transported to an off-site disposal facility.
Alternative IV, in-situ vitrification, and Alternative V,
stabilization, both would satisfy the statutory preference for an
on-site remedy including a treatment component by immobilizing
contaminated soils. In-situ vitrification also would reduce the
volume.of the contaminated material. Alternative VII, while using
a treatment technology, would require off-site disposal of the
treated material. Alternative III, cap site, and Alternative VI,
excavate and replace, do not use treatment to reduce the toxicity,
mobility, or volume of the contaminants.
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8.1.5
Short-Term Effectiveness
Short-term effectiveness refers to the speed with which the remedy
achieves protection, as well as the remedy's potential to. create
adverse impacts on human health and the environment during the
construction and implementation period.
The following are the approximate implementation times for each
alternative, from the shortest to the longest (exclusive of the
time for design, vegetation, and monitoring):
Alternative
III Cap site
VI Excavate
V Stabilization
VII Phys./chem.
IV vitrification
Implementation Time
One year
One year
Fifteen months
Eighteen months
Four years
Potential hazards during the remediation can be effectively limited
through the use of engineering controls for Alternatives III
through VII. All work would be performed using controls designed
to reduce radioactive exposure and to reduce dust exposure to below
regulatory health and safety 'standards. Security measures would be
used during remediation to protect against trespasser exposure to
gamma radiation. The alternatives with the potential to create
dust, or alternatives which take a longer time to implement and
require the most care to prevent worker exposure during remediation
are discussed below. The. differences outlined below highlight
concerns that would be controlled during remediation.
Alternatives III through VII would each involve excavation of the
contaminated soils located on the railroad rights-of-way and the
vicinity properties, and thus would require dust control measures.
Alternatives V, VI, and VII would also involve excavation' of the
contaminated soils located on the Shattuck property and thus would
require the greatest amount of care to suppress potential dust
generation during remediation. Ongoing work at the other Denver
Radium Site Operable units has demonstrated that conventional dust
control methods are effective.
The chemical treatment facility needed for Alternative VII,
physical/chemical, would involve handling a more concentrated waste
than currently exists on the site, and would therefore present
potential health and safety concerns for remedial workers.
Automation of some of the process facilities could be required in
order to reduce worker exposure.
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The longer period of time required to implement Alternative IV,
vitrification, creates a concern with the potential gamma radiation
exposure to workers. This concern is due to the length of exposure
and the proximity to the gamma radiation sources. Gamma radiation
exposure would be addressed through monitoring the workers and
could be limited, if necessary, by rotating workers.
8.1.6
Imolementabilitv
Implementability is the technical and administrative feasibility of
a remedy, including the availability of materials and services
needed to implement an alternative.
Alternatives III, V, and VI are considered generally equivalent for
implementability. The implementability of alternatives IV and VII
is less certain.
Alternatives III through VII all require conventional removal and
replacement of the contaminated soils on the railroad rights-of-way
and vicinity properties. Alternatives III through VII also include
demolition and off-site disposal of facilities located on the
Shattuck property. These aspects of. the alternatives are
technically feasible and utilize readily available equipment and
techniques.
Alternatives III, cap site, V, stabilization, and VI, excavate and
replace, employ conventional construction techniques. Excavation,
capping, and stabilization utilize equipment, materials and design
expertise that are currently available.
Alternatives IV, vitrification, V, stabilization, and VII,
physical/chemical, all require pilot testing to further refine the
design prior to implementation. Although treatability studies of
these technologies demonstrated their potential implementability,
the treatability. studies were all small-scale bench tests.
Alternative V, stabilization, uses a technology and construction
techniques that have been implemented on a large scale at other
hazardous waste sites to immobilize inorganics in soils.
Alternative IV, vitrification, uses a technology that requires dry
soils to implement. A significant concern associated with
Alternative IV, vitrification, is the technical feasibility of
adequately dewatering the site to facilitate in-situ vitrification.
In addition, the implementability of the technology on a large
scale is somewhat uncertain since the technology is innovative and
experience with large-scale implementation is very limited:'
Alternative VII, physical/chemical, involves concentrating the
radioactive materials such that handling requirements for the
resulting radioactive wastes significantly complicate the
implementability of this alternative.
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Alternatives V, stabilization, VI, excavate and replace, and VII,
physical/chemical, each include excavation of materials prior to
final disposal. Excavation permits direct verification that the
contaminated materials have been removed. This is ~n advantage
over Alternative IV, vitrification, which treats the soil in-situ.
In-situ treatment relies on sampling efforts to identify locations
requiring treatment -and for verification that contaminated
materials have been remediated.
8.1.7
Cost
Cost includes capital and operation and maintenance costs.
Cost ranks as follows from lowest to highest:
Alternative
III cap site
V Stabilization
IV vitrification
VI Excavate and replace
VII Physical/chemical
Present
Annuitv Value
15,000,000
26,600,000'
38,300,000
36,800,000
43,300,000
- 48,800,000
These costs are the estimated present yalues of the alternatives,
including annual monitoring and operation and maintenance (for on-
site remedies) utilizing a 5% discount rate for 200 years. The
term of 200 years was utilized because of the nature of the
material and. is consistent with other situations addressing
radioactive materials. The total" present value of the annual costs
for monitoring and operation and maintenance for 200 years for
Alternatives III through V is $2,400,000. These costs were not
included for Alternatives VI and VII because the off-site disposal
facility would assume operation and maintenance responsibilities.
Information indicates that the cost for off-site disposal of wastes
similar to the contaminated soils'. at this si te has varied
significantly and was potentially underestimated in the Feasibility
Study. The cost of Alternative VI, excavate and replace, is shown
as a range, because the cost of the alternative is highly dependent
upon the cost of off-site disposal of the contaminated soils. The
cost for off-site disposal could potentially exceed the range used.
for comparison. Currently there is only one' facility available
which could accept the wastes.
capital costs can potentially be !"educed for Alternatives V,
stabilization, VI, excavate and replace, and VII,
physical/chemical, if physical screening proves to be an effective
method of reducing the volume of contaminated soil.
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8.1.8
communi tv Acceptance,
Most local residents and two community associations exhibited
strong support for Alternative VI, excavate and replace, which was
presented as the preferred alternative in the proposed plan. Some
residents questioned the need for cleanup, while others felt the
proposed remediation would not be protective enough. Li ttle
comment was received on the range of alternatives except for
Alternatives V and VI. Alternative VI, excavate and replace, was
favored over Alternative V, stabilization, by some residents
because the potential for unrestricted future land use was viewed
as a greater asset to the community than a parcel with restrictions
resulting from on-site disposal. '
Shattuck Chemical Company, the property owner of the processing
facility, indicated a strong preference for Alternative V,
stabilization.
Responses to the significant comments received are found in the
attached responsiveness summary (Appendix B).
8.1.9
State Acceptance
As the lead agency for conducting the remedial investigation and
feasibility study, CDH both recommends and agrees with Alternative
V, stabilization, as providing the best balance of the nine
cri teria. Both EPA and CDH have participated in the development of
the Record of Decision.
9.0
SELECTED REMEDY
The selected remedy for the Denver Radium site Operable unit VIII
is Alternative V, stabilization. The selected alternative involves
remediation of contaminated materials located on the Shattuck
property, the railroad rights-of-way,and the vicinity properties,
including the following components: (1) . removal and reuse or
disposal of the facilities on the Shattuck property; (2) excavation
and consolidation of the contaminated soils onto the Shattuck
property, stabilization, disposal of the treated soils on-site, and
capping; (3) remedial action as required to address the
contaminated ground water which infiltrates the storm sewer located
west of the site; and (4) implementation of monitoring,
institutional controls, and operation and maintenance.
The selected remedy addresses ground water contamination through
source control. Additional active measures for ground'- water
restoration are not presently contemplated (except as required to
address the contaminated ground water which infiltrates the storm
sewer) . Ground water monitoring will be used to monitor the
disposal unit as well as to track the improvement in ground water
quality downgradient of the site. Evaluation of the monitoring
50
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data will determine whether ground water quality is improving
adequately or whether active restoration measures are warranted.
The scope and extent of the ground water monitoring of the existing
contamination may be reduced or discontinued as the downgradient
ground water quality attains ARARs, although ground water
monitoring of the disposal unit will continue. Where waste is left
in place, CERCLA requires that the site be reviewed at least every
five years to ensure protection of human heal1;h. T~erefore, ground
water monitoring of the disposal unit and five yearreview~ would
'be continued in the future, even after ARARs are attained in the
downgradient plume.
Operable unit VIII will address approximately 50,000 cubic yards of
contaminated soil. The cost estimate based on this total volume is
detailed in Table 9-1. The total cost of the selected remedy is
estimated at $26;600,000. As with the estimates for all
alternatives, this cost estimate is preliminary, with an accuracy
of minus 30% to plus 50%. The length of time required to implement
the selected alternative is approximately fifteen months. This is
the estimated time for the construction activities and does not
include the time required for remedial design~ A more detailed
schedule and cost estimate will be developed in conjunction with
the remedial design. .
Further consideration of whether physical screening of the soils
will be implemented for the project will take place during remedial
design.
The selection of this remedy is based upon the comparative analysis
of al ternati ves presented in section 8, and provides the best
balance of the nine evaluation criteria.
The following description of the selected remedy includes
discussion of the remediation goals, compliance objectives, and
methods that would be utilized to achieve these obj.ectives.
9.1
DESCRIPTION OF SELECTED REMEDY
The objective of the remedial action is to eliminate the potential
health threat posed by the site, based on contaminants which exceed
standards, or which pose unacceptable risks based on the 104 to lO~
range specified in the NCP. The selected alternative consists of
stabilization of contaminated soils in conjunction with capping and
institutiDnal controls to reduce the risk posed by the site to
acceptable levels. The primary objectives are to reduce the
potential for exposure to excess gamma radiation and radon gas
which pose the principal threats associated with the site. -
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Table 9-1
Cost Estimate for Alternative V Stabilization
1.
Remove and replace soil
2.
Railroad remediation
3.
site clearance
4.
Process soil - 50,000 cy x $200/cy
5.
Cap site
6.
Add for handling
vicinity property materials
7.
Total capital
8.
o &M - $120,000/year, or $2,400,000
present worth for 200 years
9.
Total illustrative cost
52
$ 3,300,000
800,000
8,100,000
10,000,000
1,600,000
400,000
$24,200,000
2,400,000
$26,600,000
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specific objectives include:
o
prevent excess cancer risk due to inhalation of radon
and radon decay products;
prevent exposure, contact with and/ or ingestion and
inhalation of soils or dust posing an excess cancer risk
due to gamma radiation; ,
prevent ingestion of garden produce
contaminated soi~;
prevent potential exposure to soils having radium-226
concentrations greater than 5 pci/g above background in
the top 15 em and/or 15 pCi/g "above background below'ls
em in depth; ,
prevent potential exposure
contaminants in soils; and
prevent ingestion of ground water with contaminants in
excess of ARARs or health-based concentrations if no
ARARs exist.
o
o
grown
in
o
,0
to
non-radioactive
o
stabilization will reduce radon emanation from the contaminated
soils. Facilities on the Shattuck property will be removed, and
future construction will be limited, providing additional assurance
that radon will not pose a threat. capping will be used to shield
gamma radiation and to prevent contact with the treated soils.
Both stabilization and capping will reduce the potential for dust
inhalation, ingestion, and direct contact with radiologically and
non-radiologically contaminated soils. Excavation and
stabilization of the contaminated soils will also reduce potential
risks associated with inhalation of organic compounds. Table 9-2
contains the action levels (including health-based action levels
for arsenic, selenium, and lead) for determining materials to be
excavated from all areas of the site.
Excavating ,soils above these action levels from the railroad
rights-of-way and the vicinity properties will prevent direct
contact with, or inhalation or ingestion of soils or contaminants
above acceptable standards. ~xcavation will also prevent the
ingestion of garden produce grown in contaminated soils.
The ground water quality will improve after stabilization by
attenuation. The mobility of the contaminants will be reduced,
thus limiting contaminant loading on the ground water. ARARs and
health-based concentrations will be met.
,9 . 1. 1
Removal and Reuse or Disposal of Facilities
Disposal methods for the buildings and equipment will depend on the
extent of contamination. Non-contaminated materia,ls and
contaminated materials which are adequately decontaminated during
remediation, can be recycled, sold as salvage, or disposed in a
sanitary landfill. More heavily contaminated materials which
cannot be adequately decontaminated, and radioactive residue from
53
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decontamination, will be disposed off-site as radioactive waste.
It is anticipated that the materials associated with Buildings 5
and 6, as well as the contaminated tanks and equipment, can be
effectively decontaminated. The safety of the general public will
be a primary consideration in the transportation of contaminated
materials to a disposal facility.
Demolition of asbestos-containing structures will be performed in
accordance with federal, state, and local requirements. Non-
radiologic asbestos-containing materials can be disposed of as a
solid waste at permitted landfills.
9.1.2
Excavation and Stabilization of contaminated Soils
The estimated 38,500 cubic yards of contaminated soil on the
Shattuck property are roughly 80% of the total for the site. The
other 20% of the contaminated soil is located on the railroad
rights-of-way and the vicinity properties. The contaminated soils
consist predominantly of soils contaminated with radium-226. other
contaminants of concern, including thorium-230, uranium, selenium,
and other heavy metals, have' been identified in excess of health-
based action. levels. These contaminants are predominantly co-
located with the radium-226 contaminated soils. Excavation of the
radium-contaminated soils should result in excavation of these
other contaminants where they exist. above action levels.
Verification sampling will !;)e used to determine the limits of
excavation. contamination above health-based levels, as defined in
Table 9-2, will be excavated and treated.
Excavation of contaminated Soils from the Railroad Riahts-of-Wav
and the Vicinitv prooerties
The selected remedy includes excavation and transport to the
Shattuck property of approximately 5,000 cubic yards of radium-
contaminated soils from the railroad rights-of-way, and 6,000 cubic
yards from the vicinity properties. The primary depos;Lts referred
to as the vicinity properties are located as discussed in section
5.1.3. These soils will be stabilized and disposed of on the
Shattuck property. The soils removed from the railroad rights-of-
way and the vicinity properties will be replaced with clean fill.
The potential health threat posed at the property located at 1860
South Bannock is the most immediate in comparison to the other
vicinity properties. Design and implementation of the excavation
and removal of the contamination' located at this property will be
undertaken independent of the rest of the site to insure that it is
addressed expeditiously. The materials removed from this property
will be temporarily stored on the Shattuck property until remedial
design for the entire site is complete.
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Table 9-2
Action Levels and basis for determining the materials to be
excavated
contaminant
Radium-226
Thorium-230
Uranium
Natural
. Gamma Radiation
ALARA
Arsenic
Selenium
Lead
Action Level
5 pCi/g above
background
15 pCi/g above
background
42 pci/g
75 pCi/g
20 micro-
Roentgens per
hour above.
background
As Low As
Reasonably
Achievable
160 mg{kg
490 mg{kg
540 mg/kg
comments
Surface soils, 40 CFR 192
Subpart B, averaged over 100
m2.
Subsurface soils, 40 CFR 192
Subpart B, averaged over 100
m2.
Subsurface soils based on
decay to radium-226 in 1000
years to achieve the
subsurface standard of 15
pCi{g if the concentration of
radium-226 is 0 pCi/g. If the
radium-226 concentration is
greater than 0 pCi{g the
thorium-230 action level will
.be lower. Generic protocol
for excavation of thorium-230 ,
DOE, January 25, 1989.
U.S.D.O.E. Order 5480.1
Based on the ga~~a radiation
standard for inside buildings
of 40 CFR 192, Subpart B;
relevant to identifying areas
of contamination.
Excavate radioactive materials
beyond the requirements of the
numeric standards where
consistent with remedial
objective to maintain release
of radioactivity to the
general environment as low as
is reasonably achievable.
These action levels are
health-based values for a
trespasser scenario, and thus
are appropriate for surface
areas where future use will be
restricted.
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Evaluation of SUDDlemental standards
EPA and CDH will evaluate the use of. supplemental standards for
contamination located beneath the rail lines and South Bannock
Street during remedial design. Supplemental standards are a part
of the 40 CFR 192 regulations, Subpart C, which are relevant and
appropriate to the remedy. They allow contamination to be left in
place under specified conditions.. When evaluating the
applicability of supplemental standards, EPA and CDH are required
to select remedial actions that come as close to meeting the
otherwise applicable standard as is reasonable under the
circumstances.
If it is determined that supplemental standards are not applicable
to the material located beneath the rail line and South Bannock
. Street, the standards of 40 CFR 192 Subpart B will be met.
Stabilization and On-site DisDosal
Implementation of the selected remedy requires the Shattuck
property to be permanently dedicated as a disposal site.
Stabilization will be achieved by mixing the soil with a cement
mixture designed specifically for the site based on treatability
studies. The contaminated soil will be excavated, processed by an
on-site batch plant, and placed on the Shattuck property.
Bench scale treatability testing of stabilization was conducted by
Shattuck. The tests consisted of mixing site soils with differing
. . amounts of cement, fly ash, and silica flour. The studies
indicated that stabilization immobilized radioactive contaminants
to a leachability factor of greater than 10 based on American
Nuclear Society leach tests, indicating that the mobility of the
_. contaminants within the stabilized mass is low. Radon emanation of
the treated materials was approximately one half of the 40 CFR 192
standard of 20 pCijm2js and structural stability of the stabilized
materials was in excess of 500 psi. .
Pilot scale treatability testing will be conducted during remedial
design to optimize the stabilization design, and to further
demonstrate and verify that the technology will attain performance
standards. The additional treatability testing must demonstrate
the reduction in mobility achievable by stabilization is adequate
to comply with ARARs. Modelling of the potential post-remedial
contaminant loading on the ground water, based on the treatability
studies and the remedial design, will be used to evaluate and
verify that ground water and disposal ARARs will be attained. In
addition, the remedial design must demonstrate that the remedy
manages the contamination in a manner such that any potential
release of radioactivity is at or below levels which are protective
of human health and are as low as is reasonably achievable.
56
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The potential advantages and disadvantages associated with
utilizing a clay liner beneath the stabilized materials will. be
considered during remedial design. The post-remedial reduction of
risks will be calculated based on the physical parameters developed
in the remedial design, and must demonstrate the remedy will
achieve the 6 CCR 1007-1 Part 14.19 requirement to protect. the
general population from release of radioacti vi ty such that the
annual equivalent dose levels set forth in the regulation will not
be exceeded.
The stabilized materials will be disposed of above the ground water
table. An impermeable compacted clay cap and cover will be placed
over the stabilized materials. The cap and cover will be designed
and constructed in a manner which will provide a shield from gamma
. radiation, promote drainage, minimize erosion of the cover, and
provide long-term minimization of migration of liquids .through the
stabilized soils. The cap and cover must be of adequate design to
withstand and -protect the stabilized material from freeze/thaw
conditions. The cover. will be vegetated or armored with rock
designed to control surface erosion in the event of a probable
maximum precipitation (PMP) event. The remedy as a whole will be
designed to attain a reduction in post-remedial risk consistent
with NCP requirements. See Table 9-3.
9.1.3
Inst~onal Controls., Maintenance, and Monitorinq.
Disposal of the stabilized materials on~site will be supplemented
by the use of institutional controls, maintenance, and monitoring
. to ensure the protectiveness of the selected remedy is maintained
into the future. A summary of the requirements follows:
Institutional controls
An institutional controls program will be developed to control
access to the stabilized materials. security measures such as
fencing may be considered, but will not be relied on as a means of
reducing the risk posed by the site.
Deed restrictions or annotations denoting that the property is
dedicated as a waste disposal site, shall include the following
restrictions:
. restriction against excavating into the cover and stabilized
materials
restriction to prohibit the
structures on the disposal site
construction
of
enclosed
restriction against using the ground water located beneath
the site, and
restriction to prev~nt agricultural use of the site.
57
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criteria
Permanence
Radon - Flux
. - Ambient
Gamma Radiation
ALARA
Radioactive
Release.
Inadvertent
Intrusion
stability
Table 9-3
Disposal criteria
standard
1.000 years
20 pCi/m2/s
0.5 pci/l
As Low As
Reasonably
Achievable
.25/.75/.25
millirem
. Comments.
40 CFR 1.92 Subpart A,
Design for up to 1.000 years to
the extent reasonably
achievable, and, in any case,
for at least 200 years.
Design for the probable
maximum precip.itation event..
40 CFR 1.92 Subpart A, Average
release rate.
40 CFR 1.94 Subpart A, Maximum
annua~ average at edge of
disposal unit.
Design disposal unit such that
the level of gamma radiation
present at the surface will
not exceed background by more
than the level that would be
present from 5 pci/g radium in
soil.
Disnose materials in a manner
whi~h will maintain release of
radioacti vi ty to the general
environment as low as is
reasonably achievable.
6 CCR 1.007-1 Part 14.19,
annual dose based limitation
for release of radiation to
the public.
6 CCR 1007-1 Part 14.20,
design closure to ensure
protection against inadvertent
intrusion. .
6 CCR 1007-1 Part 14.22,
design closure to achieve long
term stability and minimize
need for active maintenance to
surveillance, monitoring and
custodial care.
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Deed restrictions must be placed on the property by the owner of
the disposal facility. The owner of the disposal facility will use
reasonable efforts to seek zoning restrictions from the city and
County of Denver as further assurance that the institutional
requirements associated with the site will not inadvertently be
breached in the future. .
Financial assurance arrangements will be utilized to assure that
adequate funds are available for post remedial monitoring,
maintenance, and institutional controls.
Coordination with property owners downgradient of the site,
including regularly scheduled surveys of downgradient ground water
use will be pursued.
Maintenance
The remedy will be designed to minimize active maintenance
requirements. post-closure maintenance of the impermeable cap and
vegetative or rock armor cover will be used to ensure that the
integrity and permanence of the cap is maintained. provisions for
surveillance and repair will be established. .
post-remediation care will include a plan for taking corrective
measures if monitoring indicates that performance standards may not
be met.
Moni,torinq
The monitoring system for the site will be designed and operated to
provide early warning of releases of waste from the disposal site.
Ground water monitoring will be performed with two objectives:
The first objective will be to monitor the effectiveness of
stabilization to immobilize the contaminants. The im~act on
ground water of the disposal unit will be monitored on-site
near the downgradient edge of the disposal uni t. Ground
water monitoring of the disposal unit will be required in
perpetuity.
The second objective of ground water monitoring is to monitor
the currently existing plume of contamination. Stabilization
of the contaminated source material is expected to lead to
improvement in ground water quality, with time, as the
existing contamination .attenuates.
Design of an appropriate network of wells to monitor post-
remediation ground water quality will be performed as a part of
remedial design. Existing wells will be utilized to the extent
possible; however, further definition of the plume of contamination
59
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to the northwest of . the site is required. When the existing
contaminated plume has attenuated or flushed to the point that'
ARARs are maintained, monitoring of the plume may be reduced or
discontinued. Where waste is left in place, CERCLA requires that
the site be reviewed at least every five years to ensure protection
of human health. Therefore, ground water near the disposal unit
will continue to be monitored as part of the five-year review
requirements even after ARARs are attained in the plume.
Evaluation of the .ground water monitoring data will be used to
determine whether ground water quality is improving adequately or
whether active restoration measures are warranted.. .
9.1.4
storm Sewer Discharqe
The ground water which infiltrates into the storm sewer located to
the west of the site along south Santa Fe Drive results in a point
source discharge into the South Platte River. Corrective action as
required to comply with the Clean Water Act and Colorado Water
Quality Control regulations will be undertaken as part of the
remedial action. The means of compliance could involve eliminating
the infiltration or treating the discharge, and will be determined
during remedial design. The cost associated with remedial action
for the storm sewer is not known and will be further defined during
design.
9.2
REMEDIATION REQUIREMENTS AND PERFORMANCE STANDARDS
9.2.1
Facilities
For facilities, the remediation requirement is to remove and re-use
or dispose of all facilities on the Shattuck property.
Non-contaminated materials and contaminated materials which are
adequately decontaminated during remediation may be recycled, sold
as salvage, or disposed in a sanitary landfill. Materials which
cannot be adequately decontaminated, and radioactive residue from
decontamination processes, will be disposed off-site as radioactive
waste. Off-site disposal will comply with EPA's off-site policy
(OSWER Directive 9834.11). Demolition and disposal of asbestos-
containing structure.s must be performed in accordance with federal,
state, and local requirements.
. Specific performance standards, used to ensure attainment of the
requirements for the facilities, are:
1.
Decontamination of facilities must comply with Nuclear
Regulatory Commission (NRC) Guide 1.86, as modified by
utilization of methodologies in the NRC draft report,
"Residual Radioactive contamination from
Decommissioning: Technical Basis for Translating
contamination Levels to Annual Dose". (NUREGjCR-5512)
60
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9.2.2
2.
3.
4.
5.
6.
Radioactive waste must be disposed of at a facility
permitted to accept such waste.
Solid wastes must be disposed at a ~acility permitted to
accept such wastes.
5 CCR 1001-10 Regulation 8 contains specific
requirements for asbestos abatement and handling. These
regulations shall be met.
ASbestos-containing materials must be disposed at a
facility permitted to accept such wastes.
Radiologically-contaminated asbestos-containing
materials will be disposed off-site as a radioactive
waste in compliance with EPA's off-site policy.
All other ARARs identified in' this ROD for
decontamination and disposal of the facilities must be
met.
Soils
Remediation requirements for soils include excavating all
contaminated soils from the vicinity properties and the railroad
rights-af-way for treatment and disposal on the Shattuck property.
Soils removed from the vicinity properties and rights-of-way will
be replaced with clean fill. Contaminated soils from the Shattuck
property will a.lso be excavated and all contaminated seils will be
stabilized for permanent disposal on the Shattuck property.
Finally, the disposal area will be capped.
Specific performance standards, used to ensure attainment of the
requirements for the soils, are:
Excavation
1.
The surface and subsurface standards for radium-226 in
soils as defined in 40 CFR 192 Subpart B shall be used
as action levels to determine which soils must be
excavated for stabilization. Verification sampling will
be used to determine the limits of excavation.
Verification of thorium-230 and other contaminants will
also be required. The extent of the remediation will be
based on monitoring and sampling as the excavation
progresses. See Table 9-2 for action levels and basis
for determining the materials to be excavated.
2.
Design and implementation of the excavation and removal
of the contamination at the 1860 South Bannock property
will be undertaken independently of the rest of the site
to ensure that it is addressed expeditiously. The
61
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materials from this property will be temporarily stored
on the Shattuck property until remedial design for the
entire site is complete.
3.
Toxicity characteristic (TC) testing will be utilized to
evaluate whether there are Resource Recovery and
Conservation Act (RCRA) characteristic wastes present at
the site. To the extent that RCRA characteristic wastes
or radiologic mixed wastes are discovered during
remedial action, they shall be remediated and disposed
in accordance with state and federal requirements.
Contaminated soils removed from the vicinity and
railroad properties will be replaced with clean fill
material.
4.
5.
40 CFR 192 Subpart C identifies the criteria for
supplemental standards which will be met if contaminated
materials will be left in place under the rail lines or
South Bannock Street. These supplemental standards may
only be substituted for 40 CFR 192 Subpart B standards
if approved during the design phase.
All other ARARs identified in this ROD for excavation
must be met.
6.
Stabilization and Disposal
7.
40 CFR 192 Subpart A and Colorado Radiation Control
Regulations 6 CCR 1007-1 Parts 14.19-14.22 must be met
to implement the remedy which requires the Shattuck
property to be permanently dedicated as a disposal site.
See Table 9-3 for specific disposal criteria.
8.
pilot scale treatability testing will be conducted
during remedial design to. optimize the stabilization
design and to verify that the technology will attain
performance requirements for long-term disposal.
Treatability testing must demonstrate the reduction in
mobility to comply with ARARs.
9.
The selected remedy will be designed to be effective for
up to one thousand years, to the extent reasonably
achievable, and, in any case, for ~t least 200 years.
( 4 0 CFR 192. 02 )
10.
Institutional controls as described in Section 9.1. 3
will be required.
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11.
12.
Cappinq
13.
14.
15.
~6.
9.2.3
Financial assurance arrangements will be utilized to
assure that adequate funds are available -for post
remedial monitoring, maintenance and institutional
controls. -
All other ARARs identified- in this ROD for stabilization
and disposal must be met.
The cap will be designed to provide a shield from gamma
radiation, promote drainage, minimize erosion of th~
cover, and provide long-term minimization of migration
of liquids through the stabilized soils. stabilization
of the contaminated soils is expected to reduce radon
emanation to below the 40 CFR 192 Subpart A standard of
20 pCi/m2/s.
operation arid maintenance of the cap will be required to
ensure that the performance standards are maintained.
The cap will be designed such that the level of gamma
radiation present at the surface will not exceed the
background level by more than the gamma radiation that
would be present from 5 pCi/g of radium in soil.
The cover of the cap will be vegetated or armored with
reck to control surface erosion.
17.
All other ~~s identified in this ROD for capping must
be met.
GROUND WATER
For ground water, the remediation requirement is to prevent the
ingestion of ground water with contaminants in excess of ARARs,
TBCs or health-based concentrations if no ARARs exist. Attenuation
will improve the ground water quality after the remedy is complete.
Stabilization- of the contamination will reduce the mobility of
contaminants and reduce the loading on the ground water. Remedial
action will be required to address the contaminated ground water
which infiltrates the storm sewer located west of the site.
Specific. performance standards, used to ensure attainment of the
requirements for the ground water, are:
L
Ground water monitoring will be performed to monitor the
effectiveness of stabilization such that any ground
water loading from the disposal unit will not cause the
ground water to exceed ARARs and TBCs. (See Table 3 of
Appendix A.)
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2.
3.
9.2.4
Ground water monitoring will also be performed to
monitor the existing plume of contamination. Design of
a network of wells to mon~tor post-remediation ground
water quality will be developed during remedial design.
When. monitoring indicates that ARARs are being
maintained for the contaminated plume, the frequency of
the plume moni toring may be reduced or discontinued.
However, monitoring of ground water near the disposal
unit will continue. .
Further ground water remediation may be required if
monitoring shows that attenuation of the contamination
will not achieve ARARs.
4.
Corrective action as required to comply with the Clean
Water Act and Colorado.Wat.er Quality Control regulations
(5 CCR 1002-2 sections 3.1, 3.8, and 6.1 et.sea.) will
be undertaken to address the contaminated ground water
which infiltrates the storm sew.er west of the site. The
means of compliance will be determined during remedial
design. .
5.
5 CCR 1002-8 section 3.12.0, Classifications and Water
Quality Standards for Ground Water, is an applicable
requirement for ground water at the site. The
regulation sets an interim narrative standard that
requires that ground water be maintained at the less
restrictive of: (i) existing ambient quality as of
October 30, 1991, or (ii) that quality which meets the
most stringent criteria set forth in Tables 1 through 4
of "The Basic Standards for Ground Water. II The
regulation provides that for contaminated ground water,
the intent is not to limit remediation.. This
requirement will be met by controlling the source of
contaminants and attenuation of the ground water to the
contaminant-specific levels set forth in. Table 3 of
Appendix A. .
6.
All other ARARs identified in this ROD for ground water
must be met.
Air
.Remediation requirements for air will ensure that remedial workers
and the local population are not adversely impacted by the remedial
action. An air quality monitoring plan will be developed during
remedial design.
Specific performance standards, used to ensure attainment of the
requirements for air, are:
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1.
9.3
2.
Perimeter monitoring and compliance with Colorado Air
Quality Control Regulations (5 CCR 1001-3) for
particulate and non-radiologic parameters and, monitoring
and compliance pursuant to 10 CFR 20 for radiologic
constituents will be required. (Appendix B of 10 CFR
Part 20 provides limits for airborne concentrations of
~anium, thorium-230, andradium-226.)
Monitoring of non-radiologic constituents will be
conducted for total suspended particulate (TSP),
particulate ten microns or less in diameter (PM10), and
certain metals selected during remedial design.
3.
Remedial design will include development of an air
quality monitoring plan. During design, the number and
, location of air monitoring stations will be determined
and the necessity of monitoring for volatile and semi-
volatile compounds will be assessed.
4.
All other ARARs identified in this ROD for air must be
met.
SIGNIFICANT CHANGES
Chanae of Preferred Alternative
The selected remedy represents a significant change from the
preferred alternative presented in the proposed plan. The proposed
plan identified Alternative VI, excavate and replace, as the
agencies' preferred altarnative., Based on comments and new cost
information, CDH and EPA have re-evaluated the remedy selection
criteria and determined that Alternative V, stabilization, provides
the most appropriate balance of the nine evaluation criteria.
Alternative V, stabilization, was presented as an alternative under
consideration in the feasibility study and the proposed plan. Of
the alternatives considered in the proposed plan, Alternative VI,
excavate and replace, and Alternative V, stabilization, w,ere
presented as the most effective potential remedies based on the
initial evaluation in the, proposed plan.
The primary comments which initiated re-evaluation of the
comparison of the stabilization alternative to the excavation
alternative were the comments on the statutory preference of CERCLA
for on-site remedies; and the statutory preference for remedies
involving treatment to reduce toxicity, mobility, or volume through
treatment. Information indicating the cost for permanent off-site
disposal of the contaminated soil may be substantially higher than
the original estimate was also factored into the evaluation.
65
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A summary of the comparison of all the alternatives was presented
in section 8.. The following discussion highlights the comparison
of Alternatives V and VI and the most decisive factors in the
selection decision. '
Both alternatives would attain the threshold criteria, overall
protection of human health and the environment, and compliance with
ARARs. Alternative V, stabilization, involves institutional
controls as added assurance against inadvertent intrusion into the
cap, and dedicates the site as a disposal location. Alternative
VI, excavate and replace, involves off-site disposal of the
contaminated soils, potentially. allowing unrestricted future use of
the site; the long-term risk associated with the contaminated soils
would be managed at the off-site disposal location. Having met the
threshol~ criteria~ either remedy is eligible for selection.
Of the balancing criteria, both alternatives would provide adequate
long-term effectiveness' and permanence, and short-term
effectiveness. In addition, both alternatives are implementable
using conventional construction equipment and techniques and have
been implemented on a large scale at other hazardous waste sites.
The reduction of toxicity, mobility, or volume through treatment,
and the cost balancing criteria were the most decisive factors in
selecting Alternative V, stabilization. Stabilization satisfies
the statutory preference for treatment, utilizing stabilization to
reduce mobility. Stabilization involves mixing the contaminated
soils with cement to create a cement-like matrix which will reduce
the mobility of the contaminants, reduce the radon emanation of the
materials, and discourage inadvertent intrusion into the treated
materials. Alternative VI, excavate and replace, would not
satisfy the statutory preference for treatment. CERCLA indicates
off-site disposal without treatment is to be' the least fa'Jored
alternative, where practicable treatment technologies are
available.
Alternative V, stabilization, is estimated to cost $26.6 million.
This cost is reasonably firm in that the unit cost of' stabilizing
the materials is not expected to differ significantly if
implemented. Alternative VI, excavate and replace, is estimated to
cost $10.2 to $22.2 million more than Alternative V, stabilization.
The cost for Alternative VI, excavate and replace, is reflected as
a range to indicate the uncertainty, associated with the disposal
cost at a location which is currently the only commercially
available facility. Based on the additional cost, Alternative VI,
excavate and replace, may not be cost effective in proportion to
its overall effectiveness and it does not appear to be as cost
effective as Alternative V, stabilization.
The input from the community acceptance modifying criterion was
taken into consideration. Although local citizens and community
organizations expressed a strong preference for Alternative VI,
66
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excavate and replace, CDH and EPA are in agreement that Alternative
V, stabilization, provides the best overall balance of the nine
criteria.
The fol"lowing discussion further clarifies reasons ~lternative V,
stabilization, was selected rather than the preferred alternative
presented in the proposed plan.
CDH and EPA have concluded that the preferred alternative in the
proposed plan offers small incremental benefits regarding the
certainty and long-term effectiveness of the remedy. When compared
to the benefits and effectiveness of Alternative V, stabilization,
the large additional cost associated with Alternative VI, excavate
and replace, does not appear to be justified.
Local citizens expressed a preference for a remedy which would
allow unrestricted future use of the property. Future land use "is
not specifically addressed in the criteria; CERCLA requires
selection of the most cost effective remedy based on a balancing of
the nine criteria. The land owner of the site that would be used
for on-site disposal has expressed a desire to manage the property
as a disposal site, accepting limited land use. continued
monitoring and institutional controls associated with the selected
alternative, stabilization, would assure the" site will be
controlled.
For newly generated waste, or the consideration of siting locations
for a new commercial disposal facility, a preference for disposal
outside of a metropolitan area may be desirable and valid.
However, when addressing cleanup of existing contaminated areas,
CERCLA and the NCP require consideration of on-site alternatives.
"Where an on-site alternative would be protective, the location of
the site in a metropolitan area should not dictate selection of an
off-site remedy, especially where CERCLA and the NCP state that an
off-site remedy without treatment is the least favored.
The design of the remedy for permanence, the nature of the
stabilized materials, monitoring, and restrictions placed on the
property would adequately address any potential uncertainty with
long-term permanence. These factors would limit the potential for
future intrusion and subsequent exposure to the stabilized
materials.
67
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A final consideration which factored into the remedy selection is
CERCLA's. specific encouragement to consider on-site remedies for
sites such as Operable unit VIII, including the use of innovative
or alternative methods instead of excavation and off-site disposal,
to encourage cost effective" remediation. Section 118(m) of CERCLA
states:
It is the sense of the Congress that the President, in
selecting response action for facilities included on
the National Priorities List published under section
105 of the comprehensive Environmental Response,
Compensation, and Liability Act of 1980 because of the
presence of radon, is not required by statute or
regulations to use fully demonstrated methods,
particularly those involving the offsite transport and
disposition of contaminated material, but may use
innovative or alternative methods which protect human
health and the environment in a more cost-effecti ve
manner.
considering that both remedies would be protective of human health
and the environment, ~he CERCLA preference for on-site remedies
which utilize treatment as a primary component, and costs, CDH and
EPA have determined that Alternative V, stabilization, provides the
most appropriate balance of the nine evaluation criteria.
Additional Chanaes
An additional change from the proposed plan which" is contained in
the Record of Decision is the requirement for remedial action in
order to eliminate or treat the discharge of site-related ground
water contamination which infiltrates the storm sewer located west.
of the site. The required action will be included in the remedial
design of the selected remedy.
The selected alternative differs from the preferred alternative
presented in the proposed plan. While this remedy selection is
considered a significant change, a new public comment period is not
required because the selection is a logical" outgrowth of the
feasibility study and the proposed plan. The public's preference
for excavation and off-site disposal and objections to on-site
stabilization were expressed in the comments on the proposed plan.
10.0
STAT~~ORY DETERMINATIONS
The selected remedy meets the statutory requirements of Section 121
of CERCLA.
Remedial actions selected at Superfund sites must be protective of
human health and the environment. In addition, section 121 of
CERCLA establishes several other statutory requirements and
68
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. preferences.. These specify that when complete, the selected
remedial action for this site must comply with applicable or
relevant and appropriate environmental standards established under
state and federal environmental laws unless a statutory waiv.er is
justified. The selected remedy also must be cost-effective and
utilize permanent solutions and alternative treatment technologies
or resource recovery technologies to the maximum extent
practicable. Finally, the statute also contains a preference for
remedies that include treatment as a principal element. The
following sections discuss how the selec~ed remedy meets these
requirements.
10.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
. The selected remedy for Operable unit VIII protects human health
and the environment through.excavation and removal of contaminated
soils at the. railroad rights-of-way and at the vicinity properties
and consolidation and stabilization of these soils. and other
contaminated soils at the site on the Shattuck property. The
treated material will be capped in accordance with the standards
specified in 40 CFR 192 and table 9-3, and institutional controls
will supplement the remedy.
The selected remedy will reduce site risks to potentially exposed
. populations by stabilization and capping of the contaminated soils.
The site will not pose a health threat to nearby residents and
workers after remediation is completed. Off-site risks will be
below 10~. Design of the cap to prevent gamma radiation will be
required to limi t the on-si te maximum potential exposure to an
acceptable level. The selected alternative attains the health
protection requirements of CERCLA and the NCP.
During remedial design, the applicability of supplemental standards
for the materials located beneath the rail lines and South Bannock
Street will be considered. Supplemental standards will not be
applied if they compromise the protectiveness of the remedy. If
supplemental standards are applied, the remedial action will come
as close to meeting the otherwise applicable standard as is
reasonable under the circumstances. If employed, supplemental
standards will be evaluated under five year reviews to assure
continued protectiveness of the remedial action.
The selected remedy will immobilize the source of ground water
contamination. Restoration of ground water quality is expected to
occur through attenuation over time. The potential short-term risk
posed by contaminated ground water is acceptable, since the area of
contamination is limited, ground water is not used, and contaminant
concentrations are expected to decrease after source materials are
immobilized by stabilization.
69
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10..2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
The selectedremeGy will attain applicable or relevant and
appropriate requirements (ARARs) and other standards to be
considered (TBCs) which are appropriate to the remedy. The
following discussion summarizes the primary ARARs and TBCs for the
site. Section 9.2 and Appendix A identify the ARARs and TBCs for
the site in detail.
10..2.1
contaminant-Specific Reauirements
. Soils:
40. CFR 192 Subpart B is relevant and appropriate for the
railroad rights-of-way and. the vicinity properties. And, the
standards in 40. CFR 192 Subpart B will be used as action
. levels to determine the extent of excavation on the Shattuck
property. .
Table 9-2
excavated.
contains
the
action
levels
for
materials
to
These requirements will be met by excavation .and removal of
soils above the standards.
Facilities:
U.S. NRC Regulatory Guide 1.86, as modified by methodologies
of rlRC draft report "Residual Radioactive contamination from
Decommissioning: Technical basis for Translating
contamination Levels to Annual Dose," (NUREG/CR-5512) is a
TBC for decontamination of facilities.
Ground water:
Safe Drinking Water Act MCLs are relevant and appropriate
requirements for ground water.
5 CCR 10.0.2-8 Section 3.11.0., Basic Standards for Ground
Water, state-wide standards are applicable requirements' for
ground water; human health, secondary drinking water, and
agricultural standards are relevant and appropriate
requirements for g~ound water.
5 CCR 10.0.2-8 section 3.12.0.,
Quality Standards for Ground
requirement for ground water.
Classifications
Water, is an
and Water
applicable
Proposed ground water protection standards for uranium mill
tailings (40. CFR 192), including proposed standards for
uranium and molybdenum are TBCs for ground water.
70.
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These requirements will be met by controlling the source of
the contaminants and attenuation of the ground water.
standards in 5. CCR 1002-2 3.1, 3.8 & 6.1 et seq.
applicable for the infiltration into the storm sewer.
These standards will be met by eliminating or treating the
infiltrating ground water.
are
10..~.2
Action-Specific requirements
40 CFR 192 subpart A is relevant and appropriate for on-site
disposal.
Colorado Radiation Control regulations, 6 CCR 1007-1 part
14.19-14.22, 14.24, and 14.26.3 are relevant and appropriate
for on-site disposal.
These requirements will be met by excavating contaminated
soils, stabilization, capping, and institutional controls.
10.2.3
Location-Snecific Requirements
The State Historic Preservation Office will be notified of
the remedial action selected. in this Record of Decision and
coordination of requirements, if any, to document buildings
or other items at the site will be performed during remedial
action.
10.3
COST EFFECTIVENESS
The selected remedy is cost-effective in mitigating the principal
threat posed by the radiologically-contaminated soils, facilities,
and ground water. cost-effectiveness is determined by evaluating
the following three balancing criteria to determine overall
effectiveness: long-term effectiveness and permanence; reduction of
toxicity, mobility, or volume through treatment; and short-term
effectiveness. Overall effectiveness is then compared to cost to
ensure that the remedy is cost-effective.
The selected remedy provides the best overall effectiveness of all
alternatives considered proportional to its cost. The selected
remedy will provide long-term effectiveness and permanence by
reducing the radon emanation of the contaminated soils, shielding
gamma radioactive material to near background levels, and reducing
the potential for contaminants to leach to the ground water. The
selected remedy utilizes treatment to reduce the mobility of the
contaminants. The selected remedy will be effective in the short-
term because any short-term risks will be controlled.
71
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Al ternati ves IV, VI, and VII also would provide high overall
effectiveness. However, Alternatives IV and VII are significantly
more expensive than the selected remedy as well as having
significant uncertainty as to their implementability. Alternative
VI is also significantly more expensive, and involves off-site'
disposal without treatment, which is disfavored by CERCLA when
practicable on-site technologies exist. The selected remedy
effectively reduces the hazards posed by all of the contaminants at
the site at a lower cost'than the other alternatives.
10.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE .
The selected remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized in
a cost effective manner at the site. The selected remedy employs
stabilization as a treatment method to immobilize the contaminants.
Of those alternatives that are protective of human health and the
environment and would comply with ARARs, EPA and CDH have
determined that this selected remedy provides the best balance of
tradeoffs in terms of long-term effectiveness and permanence,
reduction in toxicity, mobility, or volume achieved through
treatment, short-term effectiveness, implementability, and cost.
The selection of this remedy also considered the statutory
preference for treatment as a principal element and State and
community acceptance.
Of the alternatives considered, Alternatives IV, V, VI, and VII
would provide adequate long-term effecti veness and permanence.
Since potential short-term risks could be addressed for all
alternatives, the short-term effectiveness criterion was not a
decisive factor in the selection decision. . 1-.lternatives IV,
vitrification, and VII, physical/chemical, are not favored because
of uncertainty as to their implementability and since they are more
costly than the selected remedy.
Alternative VI, excavate and replace, is an implementable
alternative, but is significantly more costly than the selected
alternative and does not reduce the toxicity, mobility or volume of
the contaminated soils through treatment. Since both the selected
alternative, stabilization, and Alternative VI, excavate and
replace, offer adequate long-term effectiveness and permanence,
have similar short-term effectiveness; and are implementable, the
major tradeoffs that provide the basis for this selection decision
are the reduction of toxicity, mobility, or volume through
treatment, and cost. ' '
72
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10.5
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
Stabilization of the soils results in a concrete-like material
which physically and chemically stabilizes the contaminated soil,
reducing radon emanation, and reducing the mobility of the
contaminants. The selected remedy will effectively address the
princ~pal threats PQsed by the site by reducing radon emanation
through treatment, and shielding gamma radiation by capping the
treated. materials. Therefore, the statutory preference for
remedies that employ treatment as a principal element is satisfied.
73
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-. ,~. '. ..- ~ '
APPENDIX A
.Applicable or Relevant and Appropriate Requirements
(ARARs)
'-.
,
-------
Regulation
Heal th and Envl ronmental
Protection Standards for
Uraniun and Thorlun Hi II
Tailings
Standards for Protect i on
against Radiation/licensing
of Radioactive Haterials
licensing Requirements
Disposal of Radioactive
\laste
for
Bas Ic Standards for
Ground \later. Safe
Drinking Yater Act HCls.
Basic Standards and
Hethodologi es for Surface
\later Classifications and
Numeric Standards for
the South Platte River
Basin/Regulations for
the State Discharge Permi t
System /1
citation
~O CFR Part 192
10 CFR Parts 20,
30, 40, 70j
6 CCR 1007-1
Parts 1, 2, 4, 10
10 CFR Part 61
6 CCR 1007-1
Part 14, Subparts
.2, .7, .8, .15,
.19-.22, .23.1.1,
.23.1.5, .23.1.6,
.24, .26
5 CCR 1002-8
Section 3.11.0
40 CFR 141
5 CCR 1002- 8
Sections 3.1.0,
3.8.0 and
5 CCR 1002-2
Section 6.1.0
Table 1
Iden~lflcation of ARARs
Denver Radiun Site Operable Unit VIII
~scrlpti.!!n
Applicable or
Relevant & Appropriate
or TBC
Comments
Standards for control
clean-up of uranium
processing sites.
and
Standards' to limit
radiation. ha:tards caused
by licensed activities;
licensing requirements.
Establlshe:l a system .for
classifying groundwater
a"d adopt Ing water qual ity
standards. tlCls are standards
for publ ic drinking water
systems.
Establishes system for
classifyin9 surface waters
and assl9ns nLl11erical and
narrative standards
according to use. Pol nt
source di scharge permi tt i ng
system requirements.
R & A
Appl icable .
R & A
Applicable
R & A
Applicable
R & A
Applicable
Regulations are relevant and
and approprl ate because of site
similarities.
Authority Is delegsted to the State.
Applicable, to areas of .operable Unit
VIII Included In Shattuck's license;
relevant and appropriate to .the rest
of the site.
State regulations apply If radio.
active materials are land-disposed
at an off-site hcll ity. Substantive
portions are relevant and epproprlate
to on-site disposal.
Redloactlve end organic standards
appl y to all State ground waters.
Other standards relevant and
appropriate to, non.classlfled ground-
waters. Safe Drinking \later Act HCls
are the operative ARAR unle'ss state
standards ara applicable or more
stringent.
Applicable to sewer discharge and
woul d appl y to other dl scharges to
surface water associated with the
remedial action.
-------
Regulat"lon
Colorado Hazardous Waste
Regulations
Land Disposal Restrictions
Regulations Pertaining
to Solid Waste Disposal
Sites and Facilities
colorado Air Quality
Control Act Regutetlons
occupational
Health Act
Safety and
J
e I tatlon
6 CCR 1007-3
1,0 CfR 268
6 ceR 1007.2
5 ceR 1001.2
to 1001-14
29 use 651.678
29 CfR 1910.96
29 eFR 1926.58
Teblg 1 (cont Inued)
Identification of ARARs
Denver RadiU!TI Site operable Unit VIII
Descrlptlol'l
Sets forth regulat Ions
applicable to generators and
trllnsporters of hazardous
waste and fOI' treatment,
storage, and dlsposel
facilities.
Establishes regulations
dlsposel of solid (non-
hazardous) wastes.
for
Regulations for the control
of air emlGslons.
Rcgulatus .worker health
and safety.
Applicable or
Relevant & Appropriate
or TBC
Potent i all y
Applicable
or R & A
Potentially
Applicable
or R & A .
Applicable
Applicable
R & A
Applicable
Comments
Would apply to management of
characteristic or listed
hazardous wastes if encountered.
Portions of regulations are
relevant and appropriate to
radioactive or sol id wastes.
Potentially applicable or R & A
to on-site placement if
restricted RCRA wastes are
encountered.
Applies to off-site disposal of
sol id waste (not hazardous or
radioactive).
Dust control, odor requl rements and
asbestos requl rements applicable.
Other portions of regulations are
potentially apptfcable or relevant and
appropriate If an air emissions source
Is a component of the remedy.'
Independently
Requirements
all response
"CPo
applicable.
of this act apply to
activities under the
-------
Contaminant
Pertaining
to Radioactive
Rad !L.m- 226
Thorlun-230
Radon Decay
products
Radon-222'
Radon-220
Radiation
Radiat ion
**
\JL (\Jorking level)
of alpha particles
labl e 2
Chemical -Specl flc State and Federal ARARs
Denver Radiun Site operable Unit VIII
Standard
Contominotlon
of Soils and Buildings
Less than or equal to 5 pCltg
above background within 15 cm
of the surface.
less than or equal to 15 pCl/g
above background within
subsequent 15 cm la~ers of lioll
averaged over 100 m
Clean-up level calculated using
Initial Ra-226 concentration and
assunlng period for Th-230
Ingrowth; depth of backfill may
be considered. .
Objective of remedial action to
.achleve an annual average not
to exceed 0.02 \Jl. In any case,
not to exceed 0.03 \/l..*
Average release rate from
uranium or thorlun by-product
.materlals not to exceed
20 pi coCur I es per square
meter per second (pC 11m3- s), or
Increase the annual average
concentration by more than 0.5
pCltl outside the disposal site.
Ganma radiation shall not exceed
background levels by more than
20 mlcroRoentgens per hour.
)'
Standards
radiation.
for protection against
citation
Appll cabl e or
Relevant & Appropriate
or TBC
1,0 crR 192.12(111)
R & A
Generic protocol
excavat I on of
thorlun-230, DOE,
January 25, 1981.
for
TBC
40 CFR 192. 12(b)( 1)
R & A
40 CfR 192 .01
(b)(1)(2)
40 CFR 192. ~2
(b)(1)(11)
R & A
40 CfR 192.12(b)(2)
R & A
6 CCM 1007" Part 4
Applicable
Conments
Standard
Inactive
Relevant
railroad
for clean-up of land at
uranlun processing sites.
and appropriate to the
and vicinity properties.
Protocol for excavation of Th-230
for UHTRA projects. To achieve
15 pClIg Ra-226 after 1000 years,
Th-230 clean-up level Is 42 pCl/g If
Inl tlal Ra-226 concentration Is zero.
Standard for clean-up of Inactive
uraniun processing sl tes. For
occupied or habltabl.e buildings.
Standard for post-closure management
of uranlun or thorium by-product
material. R & A to on-sl te disposal.
Standard for clean-up of Inactive
uranium processing sites. For
occupied or habitable buildings.
Applicable to all State licensees and
registrants of radioactive materials.
Substantive portions are relevant
and appropri ate to non-licensed
materials.
= Any combination of short-lived rador. decoy products
with a total energy of \30 billion electron volts.
In one liter of air that will result In the ultimate emission
-------
Contaminant
Radiation
Radiation
Radiation Dose
Radiation Dose
Radiation Dose
Table 2(contlnued)
Chemical-Specific State and federal ARARs
Denver R8dl~ 5i te Operable Unit VIII
Standard
Standards
radiation.
for protection against
Annual dose equIvalent shall not
exceed 25 mill t rems to the whol e
body, 75 milt Irems to the thyroId,
and 25 mi III rems to any other
organ of any member of the publ ic
as a result of release of
radioactive materials to the
general public.
federal Radiation Protection
Guidance (25 FR ~~02, Hay 13,
1960) as Impl emented by the
federal Radiation Council (FRC)
recommends limiting doses to
members of the general public
to I ess than 0.5 rem/year.
I CRP Publl ca t I on 26 recol1ll1ends
a whole-body dose equivalent
limit of 0.5 rem/year as applied
to critical groups of the public.
In any cases where the doses were
actual I y found to be received at
high rates over prolonged periods,
ICRP recol1ll1ends restriction of
the lifetime dose to the Individual
member ,of the public to a value
that corresponds to 0.1 rem/year.
"
/'
ICRP publication 30 provides
recommended Annual l Iml ts on
Ir.take and Derived Air
Concentrations designed to I Iml t
the Intake of radioactive
materials by workers.
; Citatloro
Appl icable or
Relevant & Appropriate
or TBC
COl1ll1ents
10 CfR 20
(as revised
5/21/91 fR
23360ff)
R & A
to NRC-li censed
Dtherwlse relevant and
Refer to regul atl ons
requirements.
Applicable
activities.
appropriate.
for specl flc
~O CfR 192.32(a)
~O CHI 192.41(d)
6 CCR 1007-1:14 .19 .
R & A'
Standard for management .of uranium
and thorium by-product materials.
Relevant and epproprlate to on-site
disposal.
fRC 1960
TBC
To the extent that members of the
general public receive doses from
site wastes, this federal guidance
is to be considered.
I CRP 26
TBC
To the extent that members of the
public receive doses from sIte
wastes, this International
guidance is to .be considered..
I CRP 30
TBC
To the extent that workers may
have radioactive material Intakes
due to the presence of site
wastes, this International guidance
Is to be considered.
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Contaminant
'Radiation Dose
Alpha and Beta-
Gamna Eml Hers
Air pollutantS
'Table .2(continued)
Chemlcal-spec(f Ic State and Federal ARARs
. Denver. Radium Site oper'able Unit VIII
Standard
Federal Guidance Report No. \1
provides Annual limits on
Intake end Derived Air
Concentrations to be Implemented
by Federal agencies to limit the
intake of radioactive materials
by workers.
Guidelines for Decontamination
of Facilities and Equipment Prior
to Release for Unrestricted Use
or Termlnat Ion of Licenses for
Radioactive Material.
National
Hazardous
Emission Standards for
Air pollutants (NESHAP)
./
C I tilt I 01'1
Appl icable or
Relevant & Appropriate
or TBC
Federal Guidance
Report No. \ \
TBC
TBC
U.S. NRr: Regulatory
Guide \ .86. NRC draft
report - Residual radio-
aCllve contamination from
decomnl ss I onlng: technical
basis for translating
contamination levels to
annual dose' methodologies.
NUREG/CR-55\2.
~o CFR 61
R & A
Comnents
To the extent that workers may
have radioactive material Intakes
due to the presence of site
wastes, this Federal guidance Is to
be considered.
These guides will be followed for
decontamination and disposal. of
radiologically contaminated
facilit les.
To the extent the remedial action
Involves the emission of regulated
constituentS, the regulations may be
relevant and appropriate.
-------
Contaminant
Ra-226 and Ra-228
Th-230 and Th-232
Gross alpha
Beta & photon emitters
Uranium
1,1-dichloroethene
1, 1, 1-trichloroethane
Trichloroethene
Tetrachloroethene
Arsenic
B.ar ium
cadmium
Chromium
Fluoride
Lead
Mercury
Nitrate
Nitrite
Selenium
silver
Chloride
Copper
J
Iron
Manganese
,:
Table 3
chemical-specific state and Federal ARARs for Ground Water
Standard
5 pCil 1
60 pCl/l
15 pCi/l
4 mrem/yr
30 pC ill
7 ug /1
200 ug/l
5 ug I 1
5 ug 11
O. 05 mg / 1
1. 0 mg / 1
0.010 mg/l
0.05 mg/l
2 . 0 mg /1
o . 05 mg /1
0.002 mg/l
10.0 mg/l
1.0 mg/l
o . 01 mg /1
0.05 mg/l
250 mg/l
o . 2 mg / 1
0.3 mg/l
o . 05 mg /1
ARAR
Applicable
Applicable
R & A
R & A
TBC
Applicable
Applicable
Applicable
Applicable
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
R & A
Comments
statewide standard' (also MCL)
statewide standard' (also MCL)
MCL
MCL
proposed 40 CFR 192 standard
statewide standard' (also MCL)
Statewide standard' (also MCL)
.Statewide standard' (a180 MCt)
Statewide standard' (also MCL)
MCL
MCL
MCL
MCL
Agricultural
MCL
MCL
MCL
Human Health standard'
standard'
MCL
MCL
Secondary Drinking water'
Agricultural standard'
s~condary Drinking Waterl
secondary Drinking Water'
-------
contaminant
pH
Sulfate
Zinc
Aluminum
Beryll ium
Cobalt
Molybdenum
Nickel
Vanadium
1
5 CCR 1002-8 3.11.0
f
Chemical-Specific state and Federal ARARs for Ground Water
Table 3fcontinued}
Standard
6.5 - 8.5
250 mg/1
2.0 mg/l
5.0 mg/l
0.1 mg/l
0.05 mg/l .
0.10 mg/l
0.20 mg/l
o . 1 mg / 1 .
~
comments
R & A
R & A
R .& A
R & A
R & A
R & A
TBC
R & A
R & A
Secondary Drinking water'
secondary Drinking Water'
Agricultural standardl
Agricultural standard'
Agricultural standardl
Agricultural standard'
proposed 40 CFR 192 standard
Agricultural standard'
Agricultural standardl
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Pa@e No.
Denver Radium Site
Operable Unit VIII
Action Specific ARARs
Standard, Rcquire.nt. CITATION
criteria, or limitation
DESCRIPTION OR
REQUIREIfENTS
Status
COKHENTS
Clean Air Act
.0 CFR 50 to 69
Nev Source Performance .0 CFR 60
Requirements
Establishes emission
standards for new air
emissions
Potentially R 1 A
If telporary air pollution
sources are constructed in
conjuc~ion with treatment
process for soils tbe
regulations may be
relevant and appropriate.
Colorado Air Quality CRS 25-7-101 to
Control Act 512
COlllon Provision 5. CCR 100H. Conduct performance tests. Applicable Substantive requirements
Regula.tions Sec. II esissions monitoring. and are applicable to air
reco rdkeep ing emission"component of the
remedy.
Regulation No. 1 5 CCR 1001-3, Establishes eDission Portions are See below for description
Reg 1 control regulations for Applicable of specific provisions.
particulat~s, smokes,
.carben monoxide, sulfur
oxides, and fugitive
particulate emissions
Regulation I. 5 CCR 1001-3. Comply with opacity App Hcab I e Less than 20 % opacity
Stationary gmissions Reg 1. Sec. limitations emitted, specific so~rce~
Source ILA.l may have ather
limitations.
5 CCR 1001-3. Hini.ize fugitive Applicable Applicable to construction
Reg 1, Sec. particulate elissioDs activiti~s. storage and
m.D handling ope~ations. haul
rGads and haul trucks. n
"
1 A to Dan-specific
sources.
5 CCR iOOl-3 Subllit fugitive App Ecabie Substanative requiremen.s
Reg 1, Sec. particulate ellission applicable. -\
m.D cantrol plan
-------
Pa~e No.
{,
Standard, 'Requiremnt. CITATIO~
criteria, or limitation
Regulation No. ~
Regalation 3'
Rcgu lat ion No.7
Regulation 8
Ambient Air Quality
Standards
Hazardous Katerials
Transportation Act
5 CCR 1001-4
Denver Radium Site
Operable Unit VIII
Action Specific ARARs
DESCRIPTION OR
REQUIREMENTS
Status
Establishes odor emission Applicable
regulations
5 CCR 1001-5, File APEN including
Reg 3. Sec. II estimation of elissions
rates
App licable
5 CCR 1001-5,
Reg 3. Sec.
IV. D.
5 CCR 1001-5,
Reg 3, Sec.
IV.D.3
No source or activity Applicable
should cause exceedence of
NAAQS or State Standard in
an attainment area
Undergo review procedure
which estilates pablic
health ilpacts frol tcxic
polll!tants
Applic=ible
s eca lOCI-9, --Establishes regulations to Applicable
Reg 7 ,control emissions of VOC's
(new and existing sources!
5 CCR 1001-10, COlplY with hazardous air Applicable
Reg 8 pollutants lilitations
5 cca 100 1-14
49 USC 1801 to
1813
Sets ambient standards for Appii~able
total suspended
particulates. sulfur
, dioxide. oxidant. GO.
nitro~en dioxide
COHHENTS
Substantive portions are
. applicable to all sources
including earthwork and
existing sources unless
specifically exelpt.
Denver is nonattainment.
however particulate less
than ten microns (PHlOI
does not ha.ve
nonattainment area.s.
therefore applicable to
PKIO.
Substantive requirements
are app 1 icable.
*pplj R~asotably Available
Control Technology (RACTI.
Section V re~uire'ents
regarding eV=iporation as
the ~ethod of disposal are
app 1 icable.
Contains specific
re~uirenents fer asbestos
handling and abatement.
~ould be applicable if
remedial ~ction ~ould
cause emission of
,egulated constituents.
'~
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Page No.
Standard, Requirellnt.. CITATION.
criteria, or lillitation
Transportation
Regulations
Colorado Hazardous
Waste Regulations.
Waste characteration
Radiation Control Act
Denver Radiull Site
Operable Dnit VIII
Action Specific ARARs
DESCRIPTION OR
REQUIREMENTS
~9 CFR parts Regulates transportation
101, 111 to 111 of hazardous laterials.
Part 113 is specific to
radioactive materials.
Status
Applicable
6 CCR 1001-3. Defines hazardous wastes, Applicable
part~ 260, 261, requires waste
262.11 characterization.
6 CCR 1001-3,
Part 26 (
CRS ,S-IHO!
to 25-11-305
5 cca 100H.
Part 1 -
6 CCR 1007-[
Part 3
Standards for owners and
Operators of Hazardous
Waste Tr~atllent. Storage,
and Disposal Facilities
General provisions
(including definitions)
. for 6 CC& 1007-1
~eguiatiQns concerning
licensing of radioactive
uteriais
Portions
potentially
applicable or R !
A
Applicable
Portions
Applicable.
Portions R & A
COMMENTS
Applicable to
transportation of
radioactive wastes froll
~uildings and facilities
to off-site disposal
facility.
TC testing will be
performed during
excavation to evaluate
whether hazardous wastes
are present.
Requirellents for
~anagellent of hazardous
wastes based uopn the lode
of managellent. i.e.
container storage. vaste
piles. impoundments. etc.
Potentialli.applicable or
relevant and appropriate
if c~aracteristic or
listed RCRA wastes are
encountered during
rellediation.
Substantive portions ar~
applicable or R & A. 1~
relledies which dispose of
radioactive materials
on-site substantive
requirements are
applicable.
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"
Page No.
. St~ndard, Require.nt. CITATION
criteria, or lilitation
Solid Wastes Disposal
Sites a~d Facilities
Act
Solid Wastes Disposal
Sites and Facilities
Regulations
6 CCR 1001-1,
Part 4
6 CCR 1007-1,
Part 10
6 CCR 1001-1,
Part 14
6 CCIL 1001-1,
Part 17
P"'.-. --~._' --
.:.6 CCR 1007-1,
Part 18
CRS 30-20-101
to 118 _.
6 CCR 1007-2
Denver Radi~1 Site
Operable Unit VIII
Action Specific ARARs
DESCRIPTION OR
REQUIREYENTS
Status
Establishes sta~dards for Applicable or R ,
protection against A
radiation hazards
Notes, instructions, and
reports to workers
Applicable or R ,
A
Establishes procedures.
criteria. and terls and
conditions upon whicb the
Department issues licenses
for land disposal of
low-level radioactive
wastes
Portions R , A
Transportation of
radioactive materials
COMYENTS
This part applies to all
licenses and registrants.
Substantive portions are
relevant and appropriate
to non-licensed areas.
Substantive portions are
applicable to licnsed
areas. R , A to
nonlice~sed areas;
Portions of substantive
requirelents i~cluding the
performance requirements
are relevant and
appropriate to on-site
disposal.
Applicable or R & Substantive portions are
A . a?plic~ble or relevant and
1ppropriate.
. Licensing requirements for Portions R.& A
.il1in6 facilities and for
th~ disposition oC
products of milling
operations for uranium.
tho rium and re bted
lIaterials
&stablishe~ minilum Potentially
standards, closure Applicable or R &
requirellents, site A
standards, and engineering
design standards for solid
vaste disposal facilities.
Portions of substantive
requir~2ent~ are relevant
and appropriate.
The s!lQstanti'le
requirellents ~ouid apply
to on-site disposal of .~.
solid waste.
-------
Pa@! No.
Standard. Requiremnt. CITATION
criteria, or limitation.
Prohibition on burial
o'f sludge
So lid Vaste
Regulations. Asbestos
Disposal
Clean \later Act
Storm ~ater discharge
regulations
Denver Radiul Site
Operable Unit VIII
Action Specific ARARs
DESCRIPTION OR
REQUIREMENTS
Status
6 CCR 1007-2, Prohibits both onsite and Potentially
2.2.11. 2.2.12 offsite burial of liquid Applicable
waste
6 CCIt 1007-2
Sec. 8
33 USC 1251 to
1316
40 cn 122,
123, 124
Require.ents for the
disposal of asbestos
containing materials
Regulates discharges of
storm water and run off
water
Colorado Water Quality CRS 25-8-101 to
Control Act 103
Basic Standards and
Methodolo@ies for
surface water
Classifications and
~umeric Standards. S.
Platte R. Basin. et al.
5 CCR 1002-8.
Section 3.1.0
5 CCR IOOH.
Section 3.3.0
State Discharge Permit 5 CCR 1002-2
Regulations Sec. 6.1.0
Establishes basic
standards. .
anti-degradation standard,
system for classifying
state waters
Used in conjunction with
Basic Standards and
Methodologies (Sec. 3.1.01
Applicable
Applicable
App 1 icad!
Applicable
Requires a permit for the Potentially
discharge of pollutants Applicable
from any point source into
waters of the State.
COMMENTS
Applicable to
non-radioactive asbestos
materials, radioactive
asbestos materials require
disposal at a facility
permitted to accept such
wastes.
Utilize Best Available
Technology (BAT) and Best
Conventional Pollutant
Control Technology
Applicable to component of
remedy i.pacting surface
water.
For any surface water
discharge identified.
compliance is required for
segment U4 of S. Platt!
Ri ve r.
Hust comply with '~
substanative requirements.
Applicable to storm sewer
discharge unless
infiltration is
eliminated.
-------
Page No..
Standard, Requiremnt, CITATION
criteria, or limitation
Basic Standards for
Ground Water
Storm Water Discharge
Regulations
Vater Well and pump
Installation
Ccntractors. Regulations
5 CCIL 1002-2
Sec. 6.9.7
5 CCR 1002-8,
Section 3.11.0
5 CCR 1002-7 .
2 r,CR 402-2
Denver Radiul Site
Operable Unit VIII
Action Specific ARARs
DESCRIPTION OR
REQUIREHEYTS
Status
Perform acute and chronic Potentially
biolonitoring tests before Applicable -
discharge is permitted
Establishes a system for Portions
classifying ground water Applicable,
and adopting water quality.Porti4ns R ! A
standards to protect
existing and potential
beneficial uses
Establishes requirements Applicable
relating to run-ofr" waters
and discharge into storm
sewers.
License require~ents for Applicable
well construction and pump
installation coatractors
and minilum standards for
we 11 construction and
abandon:aent
COHHENTS
Discretionary requirement
under the CDPS program,
these lonitoring
requirements lay be
required for point source
surface water discharge.
Establishes framework,
site-specific
classifications and
standards: Statewide
standards are applicable.
Standards bas~d on
. classification are R & A.
Colorado and federal storm
water regulations are.
applicable to rGn-off frol
the site.
Establishes regGlations
for r.or.struction ana
aoandonment of wells.
'"",
,
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Page No.
Standard, Requiremnt. CITATION
criteria, or limitation
Colorado Hazardous
Waste Act
Radiation Control
Regulation, Siting
requirements
So 1 id Waste
Regulations, Siting
requiresents
National Historic'
?reservation Act
Archaeological and
Historic Preservation
Act
CRS 25-15-101
to 313
6 CCR 100H,
Part 14
6 CCR 1001-1
Part 18
Denver Radium Site
Operable 'Unit VIII
Location Specific ARARs
DESCRIPTION OR
REQUIRKHENTS
Establishes broad siting
criteria and site .
evaluation procedures for
individual storage or
disposal units (i.e.,
ilpound.ents, landfills).
, Status
COKHENTS
Potentially Relevant and appropriate
Applicable or R 1 if waste characterization
A is hazardous.
Siting and design criteria Portions R & A
for land disposal of low
level radio~ctive waste.
Design of repository
. required to meet
performance standards of
14.19-22.
Siting and design criteria R 1 A
for uraniul and thorium
milling facilities.
6 CCR IG01-2, Siting requi~ements for
. sees. 1.1, 1.2, solid waste disposd
1.3.2, 2.1.1, si,es.
16 USC'UO, (0
eFR 6.30l!bl.
36 CFR SOO
16 USC 470, (0
eFR 5301(cl
Colorado State CRS 25-80-201
Historical Requirements to 211
Potentially
App licable
Requires federal agencies Potential-ly
to take into account the Applicable
eifect of federal projects
on sites included in or
eligible for the National
Reg ister
Procedures to provide for Potentially
~reservatioD df historical Applicable
and archeological data
that ~ight be destroyed
during a federal project
Regulates historical.
,prehistorical and
archeological resources.
Potent iall y
Applicable
Substantive portions are
relevant and appropriate
to on-site disposal of
radioactive soil.
Substantive portions are
relevant and appropriate
t~ on-site disposal of
radioactive SQils.
lIould be applicable if
solid waste is disposed
on-site.
If site is determined to
have national historic
significance. requirements
lay be applicable.
see above
State histQric
preservation office will
be notified of selected'
alternative during remdial
design to coordinate
historical requirements.
if any.
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