United States .
Environmental Protection
Agency o.
Office of
Emergency and
Remedial Response
EP AIROD/R08-901035
September 1990
L~ J
~'7'" OftJ. 'f'i3
&EPA
Superfund
Record of Decision:
I
Martin Marietta, Denver
Aerospace, CO
EPA Report Collection
Information Resource Center
US EPA Region 3
Philadelphia. PA 19107
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( REPORT DOCUMENTATION 11. REPORT NO. . I 2. 3. Recipien'" Accenion No.
PAGE EPA/ROD/R08-90/035
... Tille and SubdUe " 5. Report Data
,
SUPERFUND RECORp OF DECISION 09/24/90
Martin Marietta, Denver Aerospace, CO
6.
First Remedial Action
7. Author(.) 8. Parfonnlng Org.nlzadon Rapt. No.
8. Parfonnlng Orgalnlzadon Name and Add,n. 10. Project/Ta8klWork Unit No.
11. Contract{C) or Grant(G) No.
(C)
(G)
12. Sponaorlng Organlzadon Name .nd Addre.. 13. Type o' Report 6 Period Covered
U.S. Environmental Protection Agency
401 M Street, S.W. 800/000
washington, D.C. 20460 1..
15. Supplementary Note.
16. Abalract (LImit: 200 word.)
The 5,200-acre Martin Marietta, Denver Aerospace site is in Waterton, Jefferson County,
Colorado. The site completely surrounds 464 acres of contaminated Air Force property,
which is being addressed as a separate Superfund site. Since 1950, the Martin Marietta
Aeronautics Group (MMAG) has been conducting high technology engineering, design,
development, and manufacturing operations for the space industry on site. Types of
wastes generated during onsite activities include oils, metals, organic solvents,
wastewater, chemical process sludges, and VOCs. From 1959 to 1980, untreated, highly
concentrated waste from onsite activities was disposed of in five onsite ponds, referred
to as the Inactive Site Ponds Area. An estimated 2,100 cubic yards of waste and 24,000
cubic yards of contaminated soil are contained in the Inactive Site Ponds Area. From
1957 to 1969, solid wastes and construction debris generated at the site were disposed
of in an ll-acre landfill known as the Rifle Range Landfill. In addition, waste was
- stored in underground storage tanks in an area referred to as the Chemical Storgage
Area. Previous site remediations by MMAG from 1969 to 1985 did not address contaminant
sources or migration, but included backfilling and regrading of the Rifle Range
Landfill i consolidation of soil and wastes from two onsite disposal ponds into one pond
(See Attached Page)
17. Document Analyala L eeacrfptora
Record of Decision - Martin Marietta, Denver Aerospace, CO
First Remedial Action
Contaminated Media: soil, debris, gw
Key Contaminants: VOCs (TCE, toluene, xylenes), other organics (PCBs, pesticides,
phenols), metals (chromium, lead)
II. IdandliaralOpen-Ended Tarma
-
c. COSA TI FIeld/Group
18. AvaUablHty Statemen! 18. Security Clan (Thl. Report) 21. No. o' Page.
None 162
20. Security CIa.. (Thl. Page) 22. Prlca
. Non1=>
(4-77
50272-101
()
v
(s.. ANSI Z38.18)
See InstrucUons on Reverss
(Formerty NTIS-35)
Department o' Commerce
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EPA/ROD/R08-90/035
~artin Marietta, Denver Aerospace, CO
lirst Remedial Action
Abstract (Continued)
and covering of the ponds with soil; and operation of a ground water recovery system.
EPA investigations have identified the Inactive Site Po~ds and the Chemical Storage
areas, both located to the north of the main facility, as the two major sources of.
onsite soil and ground water contamination. This Record of Decision (ROD) addresses
remediation of onsite contaminated soil, waste/debris, and ground water. The primary
contaminants of concern affecting the soil, debris, and ground water are VOCs including
TCE; toluene, and xylenes; other organics including PCBs, pesticides, and phenols; and
metals including chromium and lead.
o
u
The selected remedial action for this site has been divided into three separate areas:
the Inactive Site Ponds Area, the Chemical Storage Area, and the ground water in the
south central portion of the site. Remediation of the Inactive Site Ponds Area includes
dewatering 1.3 million gallons of water from perched water zones; excavating and
incinerating offsite 2,100 cubic yards of organic waste/soil material from in and around
the ponds; thermally treating onsite 24,000 cubic yards of organic-contaminated soil;
solidifying and stabilizing remaining soil contaminated with inorganics; backfilling
excavated areas with the treated soil, and covering the ponds area with a
RCRA-multilayer cap. Remediation of the Chemical Storage Area includes treating
VOC-contaminated soil using in-situ soil vapor extraction, incinerating, and disposing
of offsite any residual organic-laden sludge from the thermal extraction treatment
system at the ponds area along with any spent carbon from the in-situ soil vapor
extraction process. Contaminated ground water remediation includes onsite pumping and
treatment using air stripping, carbon adsorption, ion exchange, UV photolysis/oxidation,
chemical reduction, and precipitation, followed by onsite discharge to surface water;
and ground water monitoring. The present worth cost for this remedial action is
$58,240,000, which includes an annual O&M cost of $1,231,500 for 30 years.
PERFORMANCE STANDARDS OR GOALS: Both onsite and offsite ground water will be treated to
meet SDWA MCLs or MCLGs. Chemical-specific ground water cleanup standards include
benzene 5 ug/l (MCL), arsenic 50 ug/l (MCL), chromium 50 ug/l (MCL), lead 5 ug/l (MCL),
and TCE 5 ug/l (MCL). Chemical-specific soil cleanup levels are based on soil action
levels and TCLP treatment standards including toluene 28 mg/kg (TCLP), PCB 1.0 mg/kg
(TCLP), and TCE 0.09 mg/kg (TCLP).
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()
v
RECORD OF DECISION
FOR
Martin Marietta Astronautics Group Site
WatertoD, Colorado
FINAL
September 19, 1990
..-.-.../
U:012..coaocn\mania\m1-rod.1OC
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ft
o
Ref:
lJ
MEMORANDUM
TO:
v
FROM:
SUBJECT:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY'
REGION vm
999 18th STREET - SUITE 500
DENVER, COLORADO 80202-2405
8HWM-SR
SEP 2. 4 1990
James J. Scherer
Regional Administrator
Robert L. Duprey, Direct~~~
Hazardous Waste Management DiViSitfv7 '
Recommendation to Approve the Record of Decision for
the Martin Marietta Astronautics Group (MMAG) Site
I am recommending that you sign the attached Record of
Decision (ROD) for the MMAG Site.
The selected remedy calls for the Inactive Site Ponds soils
to be treated using the following steps: de-watering;
excavation; off-site treatment and disposal of waste; thermal
extraction of backfill and alluvium; above ground stabilization
of backfill and alluvium, and cap. For the Chemical Storage
Tanks in the M3 Manufacturing Area, the selected remedy calls for
the soil to be treated using vapor extraction. For the ground
water, site-wide, ,the selected remedy calls for interception and
'treatment using five recovery well systems'across the Site. The
ground water will be treated on-site to remove organic and
inorganic contaminants. .
The remedy will be protective of human health and the
environment because it will address the principal threat, the
Inactive Site area, which is a major source of ground water
contamination. The remedy will restore ground water to a quality
that will allow for its beneficial use as a drinking water
supply. '
The remedy will accomplish this level of protection by
meeting the following remediation goals:
, .
Waste (approximately 2,100 cubic yards) in the Inactive
Site Ponds will be transported to an off-site facility
for treatment and disposal as Resource Conservation and
Recovery Act (RCRA) hazardous waste.
-------
2.
Cont~m;n~t~~ ~c11 (apnroximnt~ly 24,400 ~uhic yard~)
will be treated by removing organic contaminants and
stabilizing inorganics to prevent future impacts to
ground water quality and minimize the potential for-
contact with contaminants in the'soil.
3.
Ground water will be treated to meet drinking water
standards both on and off Site. (Restoration may take
as long as 45 years before alluvial ground water meets
drinking water standards on Site.)
IJ
\J
Two sets of comments were received on the preferred
alternative. The National Toxics Campaign recommended emission
controls for the on-site air stripper and was interested in
overseeing the work as a third party. MMAG requested flexibility
in implementing any decision made and expressed the concern that
the Environmental Protection Agency was being overly restrictive
on cleanup levels by projecting residential use in the future.
MMAG recommended another alternative be left in the ROD to
supplement the selected remedy. These comments have been
addressed in the responsiveness summary and in the ROD itself.
The State has concurred with the remedy and has been
requested to jointly sign the ROD because the Colorado Department
of Health will be overseeing the remedy implementation under RCRA
Corrective Action authority.
Attachment
2
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T,
September'19. 1990
MartIn Marietta Astronautics Group Site
Declaration for the Record of Decision
SITE NAME AND LOCATION.
Martin Marietta Astronautics Group
Waterton. Colorado
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the Martin Marietta Astronautics
Group (MMAG) site in Waterton, Colorado. The remedy includes remedianon of contaminated soil
in and around the Inactive Site Ponds and the Chemical Storage Tank area to the north of the main
manufacturing building. Additionally, the remedy includes remediatioll of cont:lmin:lted ground
water in the south central portion of the Site (including the M3 area, branches of Brush Creek, Dry
Gulch, and Filter Gulch). This remedy was developed in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act (SARA), and the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). The decision is based upon the Administrative
Record for this site.
The State of Colorado concurs with the selected remedy.
ASSESSMENT OF TIlE SITE
The actual or' threatened releases of hazardous substances and hazardous constituents from the site, if
not addressed by implementing the response action selected in this record of decision (ROD), may
present an imminent and substantial endangerm~t to public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY
The selected remedy for the Martin Marietta Astronautics Group site addresses the Inactive Site
Ponds, the Chemical Storage Tank area and ground water in the south central portion of the Site.
The objective of the remedy is to mitigate continued release of hazardous substances to the ground
water and to prevent further degradation of the aquifer both on-site and off-site. The remedy will
also prevent contaminant loading In the South Platte River which supports both domestic and
recreational uses. Additionally by removing the majority of the CODtamination from the Inactive Site
RE:Ol1-C08Q02\maniD\m2-rod.1OC
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. September 19, 1990
Ponds, the remedy will minimi7.e the potential for future human exposure to contaminants on or off-
site. The major components of the remedy include:
Inactive Site Ponds
Dewatering the perched zones and contaminated alluvium and treating the water on-site
(approximately 1 million gallons). .
Excavating waste and contaminated soil in and around the ponds for treatment.
Approximately 2,100 cubic yards of waste will be treated and disposed of off-site in
accordance with the Land Disposal Restrictions (LDRs).
(,
Treating contaminated soil (approximately 24,400 cubic yards) on-site using thermal
extraction for organic chemicals and solidification/stabilization for inorganic chemicals. Soil
which is contaminated with RCRA listed hazardous wastes will be treated to meet either the
LDR treatment standards or the soil and debris treatability variance standards.
Backfilling treated soil into the area of contamination and coveting with a multi-layered cap.
Chemical Stora~e Tank Area
Using soil vapor extraction in-situ around the Chemical Storage Tanks to remove and capture
halogenated organic chemicals.
Ground Water
Installing additional extraction systems on-site in Dry Gulch, Filter Gulch, the Chemical Mill
Sumps, Hydrostatic Test Tank area, and possibly in the East Branch of Brush Creek (north
of the Inactive Site).
Treating the recovered ground water for volatile organic compounds (VOCs) and inorganic
contaminants including heavy metals. Additionally, a process for treating N-
nitroSodimetbylamine (NDMA) will be installed.
Treating the water to meet parameters established in the Colorado Pollutant Discharge
Elimination Sys~em (COPDES) permit for the MMAG facility. Clean-up targets for the
ground water are based on federal and state drinking water standards.
Implementation of this remedy is expected to take 4 to 5 years for the Inactive Site Ponds.
Approximately 45 years may be needed to remove coptaminants in the ground water in order to meet
the remediation goals.
RE:OI1-COS0q2\martin\m2.rod.1Dc
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September 19, 1990
Statutory Determinations
The selected remedy is protective of human health and the environment, complies with Federal and
State requirements legally applicable or relevant and appropriate to the remedial action,' and is cost-
effective. The remedy uses permanent solutioDS and alternative treatment technologies to the
maximum extent practicable and satisfies the statutory preference for remedies that employ treatments
that reduce toxicity, mobility or volume as a principal element. Because this remedy. will result in
hazardous substances remaining on-site above levels that allow for unlimited use and unrestricted
exposure, a review will be conducted no less often than every five years after remediation is initiated
to ensure the remedy continues to provide protection of human health and the environment.
~. ...z.V If1C1
~~/7#-
Thomas P. Looby.
Assistant Director
Office of Health and Environmental Protection
Colorado Department of Health
~ z'1/7/O
Date
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SECTION
September 19, 1990
TABLE OF CONTENTS
~
1.0 SITE NAME, LOCATION, AND DESCRIl'TION .........................
1.1 PHYSIOGRAPHY AND MAJOR SITE FEATURES. . . . . . . . . . . . . . . . .
1
1
1.2
1.3
SURROUNDING LAND USE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
METEOROLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
5
1.4
1.5
GEOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
7
HYDROLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . .'. . . . . . . . . . . . .
2.0 SITE HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1
2.2
2.3
2.4
2.5
WASTE GENERATION AND DISPOSAL. . . . . . . . . . . . . . . . . . . . . . .
8
8
ENFORCEMENT HISTORY ................................ 9
PREVIOUS STUDIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10
REMEDIAL AC'I1VITIES ................................. 11
U.S. AIR FORCE (PIKS) PROPERTY. . . . . . . . . . . . . . . . . . . . . . . .. 11
3.0 COMMUNITY PARTICIPATION. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 11
3.1
3.2
CHRONOLOGY OF COMMUNITY PARTICIPATION AC'I1VITIES """ 13
LOCATION OF INFORMATION CENTERS ..................... 14
4.0 SITE CHARACTERIZATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ . . .. 15
4.1
4.2
4.3
4.4
SOURCES OF CONTAMINATION. . . . . . . . . . . . . . . . . . . . . . . . . .. 15
AFFECTED MEDIA AND EVALUATION OF CONTAMINATION. . . . . .. 16
MOBILITY OF CONT AMINANI'S ........................... 21
4.3.1 Ground Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21
4.3.2 Surface Water and Sediments. . . . . . . . . . . . . . . . . . . . . . . . . .. 22
MODEWNG OF CONTAMINANT MIGRATION. . . . . . . . . . . . . . . . .. 2S
i
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SECTION
September 19, 1990
TABLE OF CONTENTS
(Continued)
~
5.0 SUMMARY OF SITE RISK. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. 28
5.1
CONTAMINANT IDENTIFICATION INFORMATION. . . . . . . . . . . . . .. 28
5.1.1 Media of Concern. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 28
5.1.2 Contaminants of Concern in Each Media. . . . . . . . . . . . . . ... . . .. 29
5.1.3 Concentrations of Chemicals. . . . . . . . . . . . . . . . . . . . . . . . . .. 30
5.2
EXPOSURE ASSESSMENT INFORMATION ..................... 32
5.3
5.2.1 Exposure Pathways. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 32
5.2.2 Potential Exposed Populations. . . . . . . . . . . . . . . . . . . . . . . . .. 33
5.2.3 Monitoring or Modelling Data and Assumptions Used to Characterize
Exposure Point Concentrations. . . . . . . . . . . . . . . . . . . . . . . . .. 33
5.2.4 Assumptions of Exposure Frequency and Duration. . . . . . . . . . . . .. 34
CURRENT AND FUTURE USE SCENARIOS. . . . . . . . . . . . . . . . . . .. 34
5.3.1 Assumptions..................................... 34
, 5.3.2 Current Use Scenario. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37
5.3.3 Future Use Scenario. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37
5.4
TOXICITY ASSESSMENT INFORMATION. . . . . . . . . . . . . . . . . . . . .. 37
5.4.1 Slope Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37
5.4.2 Reference Dose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 39
5.4.3 Explanation of Toxicity Information. . . ~ . . . . . . . . . . . . . . . . . .. 39
5.5
RISK CHARACTERIZATION INFORMATION. . . . . . . . . . . . . . . . . . .. 39
5.6
5.5.1 Quantified Carcinogenic Risks for Each Contaminant of Concern in
Each Pathway. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 41
5.5.2 Combined Carcinogenic Effects. . . . . . . . . . . . . . . . . . . . . . . .. 41
5.5.3 Noncarcinogenic Effects for Each Contaminant in Each Pathway. . . .. 45
5.5.4 Combined Noncarcinogenic Effects. . . . . . . . . . . . . . . . . . . . . .. 45
5.5.5. Sources of Uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48
5.5.6 Risk Assessment Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . .. 49
ENVIRONMENTAL RISKS ......................... . . . . . .. 49
5.6.1 Critical Habitats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
5.6.2 Endangered or Threatened Species. . . . . . . . . . . . . . . . . . . . . . .. 50
6.0 DESCRIPTION OF ALTERNATIVES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
ALTERNATIVE 5-1: NO ACTION. . . . . . . . . . . . . . . . . . . . . . . . . .. 52
6.1
ii
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SECI'lON
6.2
6.3
6.4
6.5
6.6
6.7
I
6.8
6.9
September 19, 1990
TABLE OF CONTENTS
(Continued)
PAGE
ALTERNATIVE S-2: .DEWATERIRCRA CAPlIN-SITU SOIL VAPOR
EnR.AcrION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52
ALTERNATIVE S-3: DEW ATERIOFF-SITE INCINERATION AND
DISPOSAL OF WASTEIEX-SITU STABILIZATION OF BACKFILL AND
ALLUVIUMIRCRA CAPlIN-SITU SOIL VAPOR EXTRAcrION . . . . . . . .. 54
ALTERNATIVE S-4: DEW ATERION-SITE INCINERATION OF
BACKFILL, ALLUVIUM, AND W ASTE/OFF-SITE DISPOSAL OF
INCINERATED RESIDUES /EX-SITU STABILIZATION OF
INCINERATED BACKFILL AND ALLUVIUMIRCRA CAPlIN-SITU SOIL
VAPOR EX'I"RAcrION ,".. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 57
ALTERNATIVE S-5: DEWATERIOFF-SITE INCINERATION AND
DISPOSAL OF W ASTEfI"HERMAL EnR.AcrION OF BACKFILL AND
ALLUVIUM/EX-SITU STABILIZATION OF BACKFILL AND
ALLUVIUMIRCRA CAPN APOR IN-SITU SOIL VAPOR EX'I"RAcrION . .. .60
ALTERNATIVE GW-I: NO AcrION ......................... 62
ALTERNATIVE GW-2: CONTINUED OPERATION OF THE EXIS-~~NG
RECOVERY WELL SYSTEMSITREATMENT BY AIR STRIPPING,
CARBON ADSORPTION, AND ION EXCHANGEIDISCHARGE TO
BRUSH CREEK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '. 63
ALTERNATIVE GW-3: CONTINUED OPERATION OF THE EXISTING
RECOVERY WELL SYSTEMSIINSTALLA TION OF ADDmONAL
RECOVERY WELL SYSTEMS IN FILTER GULCH AND DRY GULCH
UPGRADIENT FROM THE EXISTING RECOVERY WELL
SYSTEMSrrREATMENT BY AIR STRIPPING, CARBON ADSORPTION,
ION EXCHANGE, ANDIOR UV PHOTOL YSIS-QXIDA TIONI
DISCHARGE TO BRUSH CREEK . : . . . . . . . . . . . . . . . . . . . . . . . . .. 65
ALTERNATIVE GW-4: CONTINUED OPERATION OF EXISTING
RECOVERY WELL SYSTEMSIINSTALLATION OF ADDmONAL
RECOVERY WELL SYSTEMS IN FILTER GULCH AND DRY GULCH
UPGRADIENT FROM THE EXISTING RECOVERY WELL
SYSTEMS/ADDmON OF A RECOVERY WELL SYSTEM IN THE M3
AREAITREATMENT BY CHEMICAL REDUcrION, PRECIPITATION,
CLARIFICATION, AIR STRIPPING, CARBON ADSORPTION, ION
EXCHANGE, ANDIOR UV PHOTOL YSIS-QXIDATIONIDISCHARGE TO
BRUSH CREEK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 66
7.1
7.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES. . . . . . . . . . .. 67
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
INTRODUcrION'
iii
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SECTION
7.2
"
September 19, 1990
TABLE OF CONTENTS
(Continued)
lMiE
COMPARATIVE ANALYSIS OF SOIL ALTERNATIVES. . . . . . . . . . . ., 68
7.2.1 Overall Protection of Human Health and the Environment. . . . . . . .. 68
7.2.2 Compliance with ARARs ............................. 72
7.2.3 Long-term Effectiveness and Permanence. . . . . . . . . . . . . . . . . . .. 72
7.2.4 Reduction of Toxicity, Mobility, or Volume Through Treatment. . . . .. 73
7.2.5 Short-term Effectiveness. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 74
7.2.6 Implementability................................... 75
7.2.7 Cost.......................................... 76
7.2.8 State Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 77
7.2.9 Community Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 78
7.3
COMPARATIVE ANALYSIS OF GROUND WATER ALTERNATIVES. . .. 78
7.3.1 Overall Protection of Human Health and the Environment. . . . . . . .. 78
7.3.2 Compliance with ARARs ............................. 81
7.3.3 Long-term Effectiveness and Permanence. . . . . . . . . . . . . . . . . . .. 81
7.3.4 Reduction of Toxicity, Mobility, or Volume Through Treatment. . . . .. 82
7.3.5 Short-term EffectiveneSs. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 82
7.3.6 Implementability................................... 82
7.3.7 Cost.......................................... 83
7.3.8 State Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 83
7.3.9 Community Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 84
84
8.0 SELEcrED REMEDY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.
DESCRIPTION. . . . . . . . . . . . . . . . . . . . : . . . . ~ . . . . . . . . . . . . .. 85
8.1.1 Alternative S-5: Dewater/Off-site Incineration and Disposal of
WastelIbermal Extraction of Backfill and AlluviumlEx-Situ .
Stabilization of Backfill and AlluviumlRCRA CapNapor In-Situ Soil
Vapor Extraction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 85
8.1.2 Alternative GW-4: Continued Operation of Existing Recovery Well
SystemslInstallation of Additional Recovery Well Systems In Filter
Gulch and Dry Gulch Upgradient From the Existing Recovery Well
Systems/Addition of a Recovery Well System in the M3 Ar-
earrreatment By Chemical Reduction, Precipitation, Clarification. Air
Stripping, Carbon Adsorption. Ion Exchange, and/or UV Photolysis-
OxidationlDischarge to Brush Creek. . . . . . . . . . . . . . . . . . . . . .. 95
8.2
REMEDIATION GOALS ................................. 103
8.2.1 Soil Remediation Goals (Inactive Site and Chemical Storage Tank
. Areas) . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 104
8.2.2 Ground Water Remediation Goals. . . . . . . . . . . .. . . . . . . . . . . .. 105
iv
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SECTION
September 19. 1990
TABLE OF CONTENTS
(Continued)
.l.MlE
8.3
REVISED COST ESTIMATE
" . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 107
9.0 STATUTORY DETERMINATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 107
9.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT. . . . . . 107
9.3
9.4
9.5
9.6
9.2
COMPUANCE WITH APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS (ARARs) OF ENVIRONMENTAL
LAWS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 112
9.2.1 Resource Conservation &. Recovery Act (RCRA) and
Toxic Substance Control Act (TSCA) . . . . . . . . . . . . . . . . . . . .. 113
9.2.2 Clean Water Act (CWA) &. Safe Drinking Water Act (SDWA) ..... 125
9.2.3 Clean Air Act (CAA) .............................. 125
COST-EFFECTIVENESS. . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . .. 125
USE OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO
THE MAXIMUM EXTENT PRACTICABLE. . . . . . . . . . . . . . . . . . . .. 126
PREFERENCE FOR TREATMENT AS PRINCIPAL ELEMENT. . . . . . . .. 126
CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 127
10.0 REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 127
APPENDIX A - RESPONSIVENESS SUMMARY
APPENDIX B - INACTIVE SITE PONDS CROSS SECTIONS
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Table 4-1
Table 5-1
Table 5-2
Table 5-3
Table 5~
Table 5-5
Table 7-1
Table 7-2
Table 8-1
Table 8-2
Table 8-3
Table 9-1
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Figure 1-1 . . . . .
Figure 1-2
Figure 8-1
Figure 8-2 .
Figure 8-3
Figure 8~ . . . . . . . . .
Figure 8-5 .
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TABLE OF CONTENTS
(Continued)
LIST OF TABLES
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September 19, 1990
MartIn Marietta Astronautics Group Site
Decision SUII1ID8I')' of the Record of Decision
1.0 SITE NAME, LOCATION, AND DESCRIPTION
This record of decision (ROD).describes the remedial cleanup of the Martin Marietta
Astronautics Group (MMAG) site.
The site is located in Jefferson County near the mouth of Waterton Canyon approximately 25
miles southwest of Denver (see Figure 1-1). The site occupies approximately 5,200 acres, and
completely surrounds 464 acres of U.S. Air Force property (pJKS). The site is the location of
MMAG high technology engineering, design, development, and manufacturing operations primarily
for the space industry. MMAG has produced the Titan 34D7 space launch vehicle, the MX
emplacer, and various space shuttle subsystems at the site.
1.1
PHYSIOGRAPHY AND MAJOR SITE FEATURES
The west side of the site is located in the foothills of the Rocky Mountains with elevations
ranging from 5,800 to 8,000 feet above mean sea level. The east side of the site is divided by the
Dakota Hogback into a central valley between the hogback and the foothills and the plains east of the
'hogback. The elevation of the eastern areas ranges from 5,500 to 6,000 feet above mean sea level.
The site has been subdivided into four major study areas. The first area contains plains stretching
from the eastern boundary of the site to the Dakota Hogback. The second and third areas lie
between the Dakota Hogback aDd the foothills. The North Central Valley area is north of the Lariat
GulchlBrush Creek divide, while the South Central Valley area is south of the divide. The
Precambrian Bedrock area spreads from the western edge of the central valley to the western
boundary of the site.
A majority of the development on the site is confined to the South Central Valley. The site
is further subdivided into nine separate areas (Figure 1-2). These areas include:
Kassler Area
Filter Gulch Area
Lower Brush Creek Area
M3 Area
Space Support Building (SSB) Area
1
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\
\,
.
.
'lID
~ ~
I I'
Ii-
....Q
_OOCI
co
II!!
Martin Marietta
Astronautics Group
N
1
I.u.
."
FIGURE 1.1. LOCATION OF MARTIN MARIETTA ASTRONAUTICS GROUP
SITE
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Area East or the
Dakota Hogback
()
N
Pre-Cambrian Area
O'
100' JeGO'
. I
.-.-_~~~------------- - ~
.~
FIGURE 1-2. MARTIN MARIE1TA ASTRONAUTICS GROW
SITE
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September 19, 1990
Genn Purpose Laboratory (GPL) Area
Chemical Technology Laboratory (CTL) Area
Inactive Site Area
Rifle Range Landfill Area
Most of the buildings constructed at the MMAG site are located in the M3 area and SSB
area. Other isolated laboratory facilities are located throughout the South Central Valley. Wastes
have been managed in a few areas at the site including tbe Industrial Wastewater Treatment Plant
(IWTP) located in the M3 area, five disposal ponds located in the Inactive Site area, and the Rifle
Range Landfill located in the Rifle Range Landfill area and the Evaporation Pond in the M3 area
which is a Resource Conservation and Recovery Act (RCRA) unit. .
There are five major drainages of concern at the site. Lariat Gulch drains the North Central
Valley area. The East and West Branches of Brush Creek drain the north and east sides of the South
Central Valley area, while Filter Gulch drains the southwest comer. Dry Gulch drains a small area
between the East and West Branches of Brush Creek.
. Ground-water recovery systems have been constructed on the lower reaches of both the West
Branch of Brush Creek and Filter Gulch. The recovery systems are designed to capture
CODt~minated ground water moving through the stream bed alluvium. The contaminated ground
water is piped to a treatment system and eventually discharged to Brush Creek below the recovery
system.
1.2
SURROUNDING LAND USE
The most important surrounding land use is the Denver Water Department (DWD) Kassler
Water Treatment Plant (Kassler) which borders the south side of the MMAG site. Currently, Kassler
is not operating. Formerly, Kassler plant collected surface water from the South Platte River and
ground water from the South Platte alluvium. The surface water was obtained from an intake
strUcture located approximately two miles upstream of the MMAG facility. The surface water was
piped to the Platte Canyon Reservoir for the settling of particulates prior to filtration in the concrete-
lined filter beds located adjacent to the river. FQllowing filtration, the water was chlorinated and
then transferred to an underground storage tank. Surface; water was occasionally diverted to the
Platte Canyon Reservoir via the Highline Canal and Last.Chance Ditch.
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. September 19, 1990
Ground water was Collected using a series of infiltration galleries constructed in the saturated
alluvium along the South Platte River. Ground water was withdrawn from the infilttation galleries
after collecting at the 5-sided well. The water was chlorinated and then blended with surface water
in the underground storage tank. The 5-sided well was shut down in December 1984 following the
detection of low levels of TCE in the South Platte alluvium. Last Chance Ditch may also have been
impacted by contaminated water coming from seeps in the Filter Gulch area. In December 1985, all
water tteatment operations were discontinued at the Kassler plant. The plant is maintained so that it
may be brought back on-line in the future.
The Chatfield Reservoir State Recreation area is located northeast of the MMAG site.
Chatfield Reservoir is extensively used for boating, hiking, and many other recreational activities.
The area outside the recreational area is zoned A-I and A-2, meaning that development plots must be
at least 10 acres. There are scattered residences throughout this area.
Two miles north/northeast of the site is the planned development, Chatfield Green Activity
Center. It will cover 346 acres and contain office, research, and industtial facilities as well as 600
dwelling units. Two miles northwest of the site is the Red Mesa Quarry. The area has been zoned
for industtial use only. To the west, the land is ZOii~ A-I restticting development plots to greater
than 35 acres. Only scattered residences exist in thIS area.
An inventory of ground water wells in the area surrounding the site shows that there are
currendy no wells with a domestic-use permit. Previously, five domestic-use wells were permitted in
. .
the immediate vicinity. Four wells permitted to the DWD in 1954 and 1956 were abandoned in
1971. A fifth well permitted in 1956 no longer exists.
Water. in the South Platte River is used as a source for drinking water by the city of
Englewood. The water intake is 3 miles south of Chatfield Reservoir.
1.3
METEOROLOGY
The weather at the site is typical for the east tlank of the front range of the Colorado Rocky
Mountains. It is temperate with average high temperatur~ of 70 degrees (j Fahrenheit (F) in July
and 29"F in January. It is semi-arid with an average of 17.75 inches of rainfall per year.
Atmospheric pressure is approximately 83 percent of that at sea level because of the elevation.
Humidity averages 50 percent and the mean average evaporation is between 50 inches and 60. inches
per year. Eighty percent of the precipitation falls between April 1 and September 30. Snow is
s
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September 19, 1990
possible yest rouDd, but the heaviest snow falls are in March. Prevalling winds are from. the south
and southwest at 9 miles per hour, with the strongest winds in March and April.
1.4
GEOLOGY
The oldest rock type occurring at the MMAG site is Precambrian age granite and
metamorphic roc~. These rocks make up the mountainous terrain on the west side of the site. The
Pennsylvanian age Fountain Formation nonconformably overlies the igneous and metamorphic rocks.
The'Fountain Formation is 2,200 feet thick and outcrops or subcrops below most of the Inactive Site
area, M3 area, GPL area, and Filter Gulch area. The Fountain Formation and the overlying
sediments units have been teCtOnically uplifted and now strike to the northwest and dip to the
northeast. .
The Fountain Formation consists primarily of laterally discontinuous layers of poorly sorted
conglomeratic sandstone, sandstone, and sandy and silty claystone.
The Permian age Lyons Sandstone conformably overlies the Fountain Formation. The Lyons
Sandstone is approximately 235 feet thick and consists primarily of fine-to-cOarse-grained quartz
sandstone. It is moderately resistant and forms a small hogback through the South Central Valley
area.
J
The Permian to Triassic age Lykins Formation conformably overlies the Lyons Sandstone.
The Lykins Formation includes three members: BergenlHarriman Shale, Glennon Limestone, and
Strain Shale. The basal 112 feet thick BergenIHarriman Shale consists primarily of reddish-broWD
silty shale. The 1S-foot thick Glennon Limestone is a pink and gray, thinly laminated limestone with
locally well developed secondary porosity. The 2S~foot thick Strain Shale consists primarily of
yellow-brown shale.
The Jurassic age Ralston Creek Formation disconformably overlies the Lykins Formation.
The Ralston Creek Formation is SO feet thick and consists of interbedded, fine-grained sandstone,
limestone, and shale. The Ralston Creek Formation is overlain by the Jurassic age Morrison
Formation. The Morrison Formation is approximately 360 feet thick and consists primarily of
multicolored shale with thin, interbedded sandstones and limestones. The Lykins, Ralston Creek,
and Morrison Formations are all non-resistant valley forming formations.
The Cretaceous age DakOta Group unconformably overlies the Morrison Formation.. The
32G-foot thick Dakota Group includes the South Platte and Lytle Formations. Both formations
RE:Ol1-co8OO1\maniD\rocI-\ ~9
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September 19, 1990
consiSt primaiiJy of massive, crossbedded saadstone with conglomeratic zones interbedded with lesser
amounts of shale, siltstone, aDd claystone. '!be Dakota Group is very resistant aDd forms the
prominent hogback which separates the Central Valley area from the area east of the Dakota
Hogback.
. '!be Dakota Group is overlain by the Cretaceous age Graneros Shale, Greenhorn Limestone,
Carlisle Shale, Niobrara Formation, and Pierre Shale. '!bese formations consist primarily of shale
with thin limestone beds and cumulatively are more than 6,300 feet thick. '!bey are non-resistant
and form the plains extending east of the Dakota Hogback.
'!be youngest geologic materials at the site include unconsolidated soil and alluvium. '!be
soils are loams containing differing amounts of clay, sand, and gravel. They tend to be well drained
and have moderate to low permeability. '!be alluvium is thickest in the stream drainage and is only
a thin veneer or is completely absent over the topographic high. In the Central Valley area, the
alluvium reaches a maximum thickness of 35 feet and consists primarily of silts or clayey sand with
local accumulations of clay, silt, gravel and boulders, In the Kassler area, the alluvium may reach a
thickness of 50 feet and is domin:tted by gravel and boulders.
1.5
HYDROLOGY
'!bere are two major components to the MMAG site hydrologic system: alluvial ground
water and bedrock ground water. . The interconnection between the two systems has not been
completely defined. '!be alluvial ground water occurs in narrow bands of alluvium along the major
stream drainage of Filter Gulch, the East and West Branches of Brush Creek, Dry Gulch, and the
South Platte River. The alluvium is generally thin throughout the MMAG site but reaches a
thickness of approximately 50 feet along the South Platte River.
'!be alluvial aquifer is recharged by rainfall, surface water, and discharge from the }\~ock
aquifer. The alluvial ground water tends to flow downgradient, parallel to the stream drair, ~,
eventually discharging to the South Platte River alluvium. The alluvial ground water may also
discharge to seeps, directly to surface water, or to the underlying bedrock. '!be hydraulic
conductivity of the alluvial aquifer varies from 0.032 feet per day to 212 feet per day throughout the
MMAG site.
Ground water also occurs ,in the bedrock: formations underlying the MMAG site. Bedrock
ground water flow is best characterized in the Fountain Formation underlying the Central Valley
area. Water table, semi-confined, and confined conditions exist in different areas and at different
7
RE:012.c08002\martia\rod-l-t9
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September 19, 1990
depths in th~ Fountain ~orination. Recharge may be from direct infilttation of precipitation or from
discharge from the alluvial aquifer. Ground water flow paths are variable due to lithologic
iDhomogeneities but, in general, flow is greatest parallel to strike and down dip. Overall, the ground
water flow gradient in the Fountain Formation is southeast towarii the South Platte River. On
average, the hydraulic conductivity is an order of magnitude less than in the alluvial aquifer.
Bedrock ground water flow is not as well understood as in other bedrock formations;
however, some characterization has been completed. Characterization of the hydrologic properties of
the Precambrian age igneous and metamorphic rocks indicate that ground water flow is dominated by
fracture flow and is under artesian conditions in most areas. In addition, the development of
secondary porosity has been observed in the Glennon Limestone and Morrison Formation which
results in ground water flow rates similar to the rates observed in the alluvial aquifer. Finally, the
thick, Cretaceous age, shale dominated formations east of the Dakota Hogback are believed to form a
hydrologic confining layer preventing ground water migration to the important aquifer formations in
the Denver Basin.
The surface flow in the major drainage has been measured using a flume at regular intervals
along all the creeks. The branches of Brush Creek have a combined flow rate ranging from 0
gallons per minute (gpm) to 80 gpm in the upper reaches. In the lower reaches, Brush Creek's
flowrate gains considerably due to effluent discharge from the MMAG wastewater tteatment plant.
At its mouth in the Kassler area, it has a flow rate of 300 gpm to 1,000 gpm. Both Filter Gulch and
Lariat Gulch have flow rates ranging from ~ gpm to 20 gpm. The South Platte River has flow rates
ranging from 0.1 cubic feet per second (c:fs) to 5,700 c:fs. The DWD is required to maintain a flow
rate of 30 c:fs. The infilttation galleries at Kassler allow surface water to be diverted into the South
Platte alluvium near the S-sided well.
2.0 SITE msrORY
MMAG purchased the site in the mid-19SOs and subsequently built the manufacturing
facilities in what is known as the M3 area. In the mid-I960s, the space park facilities were built in
the Space Support Building (SSB) area. Isolated laboratories have been built at the site periodically
since the 19605.
2.1
WASTE GENERATION AND DISPOSAL
The main waste types generated by on-site activities are various oils, fluoride, aluminum,
chromium, titanium, niUate, cyanide, organic solvents, acid etching sludges, chemical tteatment
RE:Ol1-OO8OO2\awtiD\rod-1-49
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September 19, 1990
, .
sludges, and propellants. From 1959 to September 1980, all the waste that could not be treated on-
site was disposed of in the five Inactive Site Ponds. Two of the ponds were used on a regular basis,
while the other three were used sporadically. The ponds cover approximately 4.1 acres. Ponds 1
and 4 may have had clay liners at one time. However, site investigations indicate that no pond is
completely lined with clay.
The one on-site landfill, Rifle Range Landfill, was active from 1957 to 1969. From 1957 to
the early 19605, it was used as a source for sand and gravel. From the early 1960s to 1968, it was
used for the disposal of refuse, construction debris, and other solid wastes generated on-site. In
1969, it was backfilled and regraded. It covers approximately 11 acres, is 1,200 feet long and
between 100 feet and 500 feet wide.
MMAG built a wastewater treatment plant in the M3 area during initial development. The
wastewater treatment plant was designed to handle the septic and indus~ial waste generated on-site.
The current treatment process includes chemical treatment, precipitation, filtration, and sludge
separation. Industrial waste is stored in tanks and sumps before transportation to the wastewater
treatment plant. Ground water from the extraction well systems is also piped to the treatment plant
and stored in a tank prior to treatment. All the wastewater is stored in a tank after treatment during
chemical analysis to determine compliance with standards of the discharge permit. The effluent is
finally discharged to Brush Creek under permit number COPDES #CQ..OOI511.
The current container storage area has been in operation since RCRA requirements went in
effect in 1981. All waste that cannot be treated on-site is containerized and shipped to the container
storage facility. MMAG is presently seeking a RCRA operating permit.
2.2
ENFORCEMENT HISTORY
On November 17, 1980, pursuant to section 3005 of RCRA, MMAG filed a RCRA Part A
" ,
application for the treatment, storage, and disposal of hazardous waste at the facility. Revised Part
A applications were submitted in 1985, and a Part B was submitted in November 1985. In August
1990, MMAG submitted a revised Part B application which is under review at the Colorado
Department of Health (CDH).
On February 27 and March 14, 1985, CDH and EPA, respectively, issued Administrative
Orders requiring M' rAG to address contaminant releases that were detected in the Kassler area
southeast of the M~...,.G property: The MMAG site was propo~ 'for listing on the National
Priorities List (NFL) on September 5, 1985 based upon the find!!..; of a site inspection and evaluation
9
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September 19. 1990
of the site ~ks using the bazard ranking system; On February 7. 1986. EPA and MMAG signed
the Administrative Order on Consent pursuant to section 106(a) of CERCLA and section 3008(b) of
RCRA. Under this agreement, MMAG conducted a remedial investigation and feasibility study
(RIIFS) in accordance with provisions of the NCP. The remedy .is being selected under the NCP and
CERCLA. However, EPA anticipates this remedy will be implemented under the RCRA authority.
Hazardous waste management units at the MMAG facility are undergoing closure in
compliance with an Administrative Order with CDH. CDH was authorized to implement the RCRA
program in 1984 and is responsible for regulating the MMAG facility.
The Hazardous and Solid Waste Amendments (HSWA) of 1984 expanded the scope of the
RCRA program to include provisions that allow EP A to require corrective action when there is a
release of hazardous waste or constituents from any solid waste management unit at an interim status
or permitted facility. CDH now bas the authority to require corrective action at facilities operating
under interim statUS or a permit, including the MMAG Facility. It is EP A policy to defer placing
sites on the NPL that can be addressed by RCRA corrective action authorities. Since the MMAG
facility satisfies this policy, EP A bas dropped the MMAG site from the proposed NPL. Because the
~emedy selected in this ROD is consistent with both CERCLA and RCRA, the remedy will be
implemented using the corrective action authority under RCRA.
MMAG operates a wastewater treatment plant for which CDH bas issued a COPDES permit.
Additionally. the facility bas an air emissions permit from CDH.
2.3
PREVIOUS S'I1JDIES
In 1961, MMAG began sampling selected monitoring wells for inorganic contamination. In
1981 in compliance with RCRA regulations. ground water monitoring of all RCRA and non-RCRA
facilities began. In February 1986, large scale site investigations began. A complete. listing of all
the reports generated can be found in Tables 2, 3, and 4 of the RI report (Geraghty & Miller,
199Oa). A brief description of the activities and results of each report can be found on pages 6
through 19 of the final RI report. The RI was finalized in March 1990 and the FS was finalized in
June 1990.
RE:012-c08002\manin\rod-1-49
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September 19, 1990
2.4
REMEDIAL ACI'IVITIES
Besides the cleanup of some small spUls aDd RCRA unit closures, there have been four
remediation efforts undertaken at the site. The first was the bac1ffi1ling and regrading of the Rifle
Range Landfill in 1969. This effort did not ad~ess any of the contaminant sources or the migration
of contaminants. The second remediation effort occurred when the contents of Pond 2 were
bulldozed into Pond 1 and all the ponds were covered with soil fill in 1980. This effort did little to
contain contaminant sources or to prevent contaminant migration. The third effort became necessary
when contamination in the ground water was detected off-site. In September 1985, MMAG began
operation of a ground water recovery system across Filter Gulch. Between 6,500 gallons and 10,000
gallons of contaminated ground water are recovered each day and sent to the wastewater treatment
plant. In Apri11987, MMAG began operation of the West Branch of Brush Creek recovery well
system. The 3 24-inch recovery wells in a gravel backfilled trench recover between 18,000 gallons
and 28,000 gallons of contaminated water per day. The water is piped. to the MMAG Industrial
Wastewater Treatment Plant (IWTP) for treatment.
2.5
u.s. AIR FORCE (PJKS) PROPERTY
The U.S. Air Force owns approximately 464 acres within the MMAG property. It is an
NPL site, and it is being addressed separately from the MMAG site.
Portions of an RIIFS have been con~ucted by the Air Force, and an interagency Agreement
is being negotiated with EP A, CDH and the Air Force to complete work at the site.
Contami"ation from the Air Force property has migrated onto MMAG property. There are
two locations, upper reaches of Brush Creek and Lariat Gulch, where contaminants emanate from
Air Force property. EP A anticipates that source controls wUl be addressed by the Air Force, but
ground water may be addressed by both MMAG and the Air Force.
3.0 COMMUNITY PARTICIPATION
Community relations activities for the MMAG site began in February 1986 when EP A
interviewed local officials, area residents, various group representatives, CDH personnel, and other
EP A personnel. The individuals represented a cross-section of diverse interests, including state and
local government, environmental groups, peace and anti-nuclear groups, homeowner groups, and area .
business and civic groups. '
11
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September 19, 1990
The interviews were based on questions' recommended for on-site discussion as outlined in
the -Interim CommunitY Relations in Superfund Handbook,- dated 1983. The interViews were
conducted informally and interViewees were encouraged to expand on comments according to their
interests. EPA also maintained regular contact with interested groups and individuals, congressional
offices, the governor's office of Colorado, and the mayor's office of Denver.
On March 24, 1986, EPA held a public meeting at Columbine High School to explain the
Superfund process and the Administrative Consent Order issued by EP A in February 1986 to Martin
Marietta.
On March 24, 1986, EPA also produced an initial fact sheet. This fact sheet provided
background information on the MMAG site, information on studies to occur at the site, and
community relations information. The fact sheet also requested comments on the RIIFS work plan
and address information.
On May 29, 1986, interested groups, members of Governor Richard Lamm's staff, EPA,
CDH, and MMAG officials met to discuss the' possible formation of a governor's monitoring
committee for the MMAG site. It was decided that a monitoring committee was not necessary.
However, it was agreed that to maintain community involvement, EP A would produce a series of
information updates and schedule quarterly public meetings.
As a result, EPA produced eleven information updates from June 1986 through November
1989; scheduled quarterly public meetings as agreed to by Governor Richard Lamm, interested
citizens, EPA, and CDH; and held a site tour on June 8, 1986. EPA held the first quarterly public
meeting for the site on July 17, 1986.
In June 1986, EPA finalized the community relations plan (CRP). EPA based the CRP on
information gathered through interviews and meetings. The resulting CRP outlined citizen concerns
and identified the methods by which EP A would keep citizens informed and involved in decisions
about studies at the site.
On September 11, 1986, EPA attended a meeting of the Deer Creek Mesa Homeowner's
Association to discuss the area geology, hydrology, and the studies at the site in relation to
homeowner wells. EPA subsequently sampled 10 wells in the area to determine if contamination had
reached any potable wells in the Deer Creek Mesa area.
RE:Ol1..cosOO1\marWa\rod-1~9
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September 19, 1990
. EPA ~so compiled and maintained a mailing list of approximately 300 names and addresses.
Announcements and updates were regularly sent to this mailin& list. Public meetings were regularly
announced in the information updates and in local newspapers. EP A also produced a number of
press releases during the early stages of activity at the site announcing the Administrative Order on
Consent, site activities, and public meetings.
. By September 1987, EPA had held five public meetings. Less than 10 community members
attended the last three meetings. Due to this low attendance, EPA issued a letter on August 24,
1987 to everyone on the mailing list stating that unless there was significant community opposition,
EP A would discontinue the quarterly public meetings. Only one letter was received opposing
discontinuation of these meetings. EP A continued holding public meetings at key points during the .
remaining stages of the Superfund studies at the site.
3.1
CHRONOLOGY OF COMMUNITY PARTICIPATION ACTIVITIES
RI Documents
EP A obtained public commem on the RI documents produced for the site as outlined in the
CRP. Initially, MMAG submitted a draft work plan for the entire RIlFS to EPA on March 10,
1986. On March 11, 1986, EPA published a press release announcing the beginning of the public
. comment period on the work plan and to announce the March 24 public meeting. The public
comment period was scheduled to continue through March 28, 1986.
. EP A obtained public comment on this document at the public meeting held at Columbine
High School. EPA also accepted public comments in writing, by mail, and over the phone. Along
with the public comments received, EP A provided technical comments to - \fAG on the work plan
document. The work plan established that the RI would be performed in three phases and that a
report would be completed and public comment received after each phase.
In June 1987, EPA announced a regular quarterly meeting. EPA also announced that public
comments would be accepted on the Phase 1 report, which detailed the studies conducted since the
beginning of the project. The report also incorporated the results of hydrogeologic, soils, and water
quality investigations at the facility since October 1985. The meeting was held on June 23 and the
public comment period ended on July 10, 1987. No public comments were received during that time
period.
13
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September 19, 1990
Once. Phase 1 was completed, work began on Phase 2. Phase 2 was designed to conduct
additional investigationS at sites within the MMAG facility which were identified in Phase 1 as
potential sources of contamination. Phase 2 identified four sites that required further study.,
1)
2)
3)
4)
The Vertical Test Facility/General Purpose Lab Ditch (m the Brush Creek vicinity)
The abandoned waste lines from the Chem Mill to the IWTP
The west side of the factory acid and alkaline solution spills
The Chemical Storage Tanks betWeen the north door of the factory and the Hydrostat
Test Facility
On November 1, 1988, EPA held a public meeting to discuss the results of the Phase 2
investigations. Subsequently, Phase 3 began an effort to better determine the extent of contamination
at the four locations identified in Phase 2.
Feasibility Study
After completion of the three-phased RI, EPA and MMAG completed an FS describing
various alternatives for site cleanup based on contaminants identified in the RI. The FS was finalized
in June 1990. '
The public comment period for the FS and proposed plan began June 28, 1990 and ended on
August 27, 1990. A public meeting to provide information on the preferred alternative and to collect
comments was held on July 26, 1990 at Deer Cteek Junior High School. The proposed plan. which
included an announcement of the public comment period and meeting, was sent to all individuals on
the mailing list. The meeting was also announced in display ads in the Denver Post. ~
Mountain News, and the Lakewood and Littleton Sentinels. These were also the official notices of
availability of the proposed plan for review and comment. The FS and proposed plan were added to
the information centers for public comment.
3.2
LOCATION OF INFORMATION CENTERS
EP A identified five information centers for availability of site documents for public review.
The RIlFS. proposed plan, and other related documents are available for review at these five
locations. Other related documents available at the centers include the 1986 Administrative Order on
Consent, public health evaluation and environmental assessment, various ground water reports,
updates, the CRP, and work plans. The locations are as follows:
RE:012-C08002\awniD\rocI-1-49
14
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September 19, 1990
.
. Lakewood Public Library
10200 W. 20th Avenue
Lakewood, CO 80215
Denver Public Library
1357 Broadway
Denver, CO 80203 I
.
.
Colorado Department of Health
Room 351
4210 E. 11th Avenue
Denver, CO 80220
Columbine Public Library
7706 W. Bowles Avenue
Littleton, CO 80123
.
.
EP A Library
U. S. Environmental Protection Agency
999 18th Street, Suite 215
Denver, CO 80202-2413
The administrative record is also available for public review at the Superfund Records Center
on the fifth floor of the EPA building, located at 999 18th Street in Denver, Colorado.
4.1
4.0 SITE CllARACfERIZATION
SOURCES OF CONTAMINATION
. .
During the course of 30 years of operations at the facility, contamination of the soil and
water on-site has occurred and is attributable to several sou;-. '.5. The objective of the RI was to
identify those sources and define the nature and extent of the contamination from those sources. The
scope of the RI was limited to areas not already addressed under the RCRA program implemented by
the State of Colorado since 1984. Additionally, the study did not include the U.S. Air Force (pJKS)
property because there is a separate RIlFS being conducted for the Air Force property which is an
NPL site.
The RI was conducted in several phases and the results of each phase are described in the RI
report (Geraghty & Miller, March 1990). The final RI had identified the Inactive Site Ponds as the
major source of soil and ground-water contamination at the site. Additional areas of contamination
that were evaluated in the last phase of the RI, Phase 2, included the Chemical Storage Tank area,
Abandon Waste Line, the Vertical, Test Facility/General Purpose Lab Ditch ~d the West Side of
15
RE:OI2.c0&002\martia\rod-1-49
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September 19. 1990
FactOry spUls. Of these additionallocatioDS. the Chemical Storage Tank area near the north door of
the factory is the only location where significant levels of cont~minHion were found in the soil.
The Rifle Range Landfill was also investigated and the reSults showed no contaminant levels
of concern in the landfill. There are low levels of ground water cont~minHion below the landfill that
may emanate from areas upgradient.
4.2
AFFECI'ED MEDIA AND EVALUATION OF. CONTAMINATION
The Inactive Site area. the principal threat at the site. contains highly concentrated waste
from the manufacturing operations. The wastes types include waste oil. wastewater treatment and
chemical processes sludges containing fluoride. aluminum. chromium. titanium. nitrate and cyanide,
and halogenated solvents. These sludges include wastes classified as FOOl. F002. FOOS and F019
RCRA listed waste. There are five ponds that were originally used for waste disposal.
Cont~mination has since migrated into the soil and bedrock surrounding the ponds. An estimated
2,100 cubic yards (cy) of waste and 24.000 cy of contaminated soils are contained in the area.
Because the ground water intersects portions of the Inactive Site area and infiltration has carried
contaminants into the ground water. extenSive ground water conwninHion has also resultC:d.
Bedrock and alluvium have been highly contaminated by chemicals leaching from the ponds.
Below Pond 1. waste has infiltrated directly into the bedrock in the northeastern edge of the pond
and contaJ11in~ted saturated and unsaturated alluvium under the south central area of the pond.
. Concentrations in tb.e alluvial ground water are approximately an order of magnitude higher than in
perched water found in the Inactive Site pond area. This indicates that contaminant levels are likely
higher in the alluvium than in the ponds.
The soil contamination below Pond 1 (alluvium) is not uniform according to the soil core
samples. This suggests that there is a discrete nonaqueous phase liquid (DNAPL) phase present.
Mackay and others (Mackey, 1985) maintain that due to diffusional limitations and dilution by
dispersion. the water in contact with organic liquid phases generally has cont~minant concentration
levels that rarely exceed 10 percent of the satUration limit. The ground water in the alluvium below
Pond 1 has TCE in concentrations exceeding 19 percent ~f TCE satUration limit. If the direction of
alluvial ground water flow follows the slope of the bedrock surface. the alluvial ground water is
moving to the south. There is the possibility that the bedrock discharges ground water to the
alluvium underneath or upgradient of Pond 1. The RI determined that bedrock ground water flow is
greatest parallel to strike. An examination of the water level data upgradient and parallel to the
strike of the Fountain Formation indicates that the water table must dip steeply to prevent bedrock
RE:012.cQ8002\maniD\rod-1-49
16
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September 19, 1990
growid water from discharging into the alluvium. It is more likely that the water table observed in
the bedrock uplfldient is hydrologically connected to the water table present in the alluvium under
Pond 1.
The material contained within Pond 2 was moved into Pond 1 in 1980. The core logs of the
soil borings in Pond 2 indicate that there is no waste material left. Chemical analysis of samples
taken from within the ponds have low levels of VOCs (less than 100 micrograms per kilogram
(uglkg» and moderateievels of chromium {up to 464 milligrams per kilogram (mglkg». Pond 2 is
located directly above the bedrock and there is no alluvium or alluvial ground water below the pond.
Pond 3 is also located directly above the bedrock. It contains up to 5 feet of mixed waste
and clay. Detectable VOC concentration levels in the waste material range .from 136 uglkg tl -} ,120
uglkg and the chromium concentration ranges from 9.6 mglkg to 44 mglkg. No piezometers have
been installed in Pond 3; therefore the best available evidence in the core logs suggests that the waste
material in the pond and the alluvium around the pond is satUrated. The level of contamination in
the .ground water and the lateral extent of ground-water contamination are unknown.
Soil and ground water in and under Pond 4 are highly contaminated. Core samples taken
from the waste material have TCE concentrations as great as 74,000 uglkg and chromium
concentrations as great as 42,500 mglkg. The alluvium below the ponds has TCE concentrations as
great as 6,500,000 uglkg (0.65 wt%) and chromium concentrations as great as 5,360 mgllcg. More
significant than this is the distribution of theTCE with depth. A concentration of 6,500,000 ugllcg
of TCE was detected in a three foot core sample (SCB-28; 20 feet to 23 feet) taken from the
alluvium in a low point in the bedrock. There is no discrete waste found directly above where the
sample was taken. Since 6,500,000 ugllcg is substantially higher than the solubility of TCE in water
(1,100,000 ugll) and since the amount of organic carbon needed to completely adsorb the excess
TCE is approximately an order of magnitude higher than expected, it is very likely that the TCE
exists as a discrete phase. .
Like Pond I, there are two distinct layers of ground water in Pond 4. 1be upper layer
occurs is perched water within the pond; Water level measurements in well GM-142 indicate that
the upper layer is not permanent. It ranges in thickness from near 0 feet to over 6 feet. The lower
hydrologic layer occurs in the alluvium approxu..ately 7 feet below the upper laver. It is more than
4-feet thick. The upper layer has VOC concentrations as high as 13,200 ugll and the lower layer has
"VOC concentrations as high as 596,000 ugll. Thus, the trend in TCE concentration observed in the
soil borings is mimicked by the ground water. The direction of alluvial ground water flow follows
the slope of the bedrock surface; the alluvial ground water is moving to the southeast.
RE:012.c0s002\maItiD\rocI-l~9
17
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September 19, 1990
The levels of contamination present in 'and under Pond 5 are the highest measured at the site.
There are only four borings within the pond area and only one of these was sampled for chemical
characterization. The highest measured TCE concentration is 7,100,000 uglkg for the waste
materials and 3,300,000 uglkg for the alluvium. Both are significantly higher than the solubility of
TCE in water. Unlike Ponds 1 and 4, both the waste material and the alluvium are contained within
one hydrologic layer. Pond 5 sits in a depression in the bedrock that is lined with approximately 3
. feet of alluvium. The thickness of the saturated zone above the bedrock is estim!:lted to be 7 feet and
it is flowing to the southeast.
The highest observed contaminant concentrations in Ponds 1, 4, and 5 are allloc:ated at low
spots in the waste mix/alluvium interface or alluviumlbedroc:k interface. The similar trend in all the
ponds suggests that a dense pbase bas migrated intO depressions.
A summary of the chemicals of potential concern in the Inactive Site soils and the detected
concentration range is given in Table 4-1. A cross section of the ponds showing contaminant
profiles is presented in Appendix B.
Contamination from the ponds has migrated with the bedrock and alluvial ground water.
Contamination in the bedrock bas migrated at least 800 feet doWD dip in the Fountain Formation.
Most of the contamination detected north of the ponds can be attributed to down dip migration.
Ultimately, the contamination migrating down dip will move to depths of over 6,000 feet under the
Denver Basin. As described in Section 1.4, the formations which subcrop under the MMAG facility
are overlain by approximately 5,000 feet of shale which should prevent contamination from moving
into utilized aquifers. Contamination is also migrating along strike to the southeast. Both migration
parallel to strike and recharge from the contaminated alluvial aquifer can explain the distribution of
contaminants in the bedrock south of the ponds using the data on hand. It is impossible to
distinguish how the contamination migrated to its present position. The bedrock shows high levels of
contamination over 2,000 feet south along strike. A ridge of resistant bedrock is preventing large
amounts of contamination from entering the upper reaches of the West Branch of Brush Creek.
Similarly, the Lyons sandstone is preventing large amounts of contamination from entering the SSB
area. The amount of contaminant migration across strike is unknoWD. The distribution of
cont~mination in the Rifle Range Landfill area suggests that there is another TCE source besides the
landfill. The most obvious source is the Inactive Site; however the evidence is not conc:lusive.
The other contaminant source area identified by the RI is the soil contamin8!ion around the
Chemical Storage Tanks. The four Contaminants detected in the soil at the Chemical Storage Tank
area are TCE, 1,1,1-trich1oroethane (TCA), l,l-dichloroethene (DCE), and total nitrogen. The
1"8
IlE:OI2-Cj)8002'-rtiD\rocI-1-49
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September 19, 1990
. TABLE 4-1
MARTIN MARlE'ITA ASl'RONAtmCS GROUP SITE
CONCENTRATION RANGE FOR CHEMICALS QF CONCERN
INACTIVE SITE POND AREA
Chemicals of Concern
Total Concentration
Range
low high
VOLATILE ORGANIC COMPOUNDS, uglkg
Acetone 113 8,480
2-Butanone 374 23,500 .
1,l-Dichloroethane 57 2,860
cis-l,2-Dichloroethylene 51 126,000
trans-l,2-Dichloroethylene 63 63
Ethylbenzene 35 105,000
Methylene chloride 1,260 179,000
4-Methyl-2-pentanone 244 4,750
Tetrachloroethylene 41 1,100,000
Toluene 86 607,000
1,1,1- Trichloroethane 41 163,000
Trichloroethene 43 7,100,000
m-Xylenes 68 232,000
o+p-Xylenes 108 238,000
SEMI-VOLATILE ORGANIC COMPOUNDS, uglkg
Anthracen~ 2,740 2,740
Benzo(a)anthracene 2,090 4,300
Benzo(a)pyrene 3,120 3,600
Benzo(ghi)perylene 3,500 3,500
Benzo(b + k)tluoranthenes 3,180 6. ., ')0
Bis(2-ethylhexyl)phthalate 2,060 9,..20
Chrysene 2,160 4,730
Di-n-bu~lphthalate 1,710 2,980
Fluoran ene 1,880 14,700
lndeno(I,2,3-cd)pyrene 1,740 1,890
PhenAnthrene 2,000 14,100
Pyrene 1,770 8,760
1,2,4- Tricblorobenzene 2,480 4,930
Phenol nd nd
PCB - 1242 371 79,800
PCB - 1248 1,310 12,800
PCB - 1254 177 5,600
PCB - 1260 1,060 14,400
19
RE:012-C01OO2~aniD\RodIbI.~ I \ale:
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September 19, 1990
TABLE 4-1 (continued)
MARTIN MARIE'lTA ASTRONAUTICS GROUP SITE
CONCENTRATION RANGE .FOR CHEMICALS OF CONCERN
INACTIVE SITE POND AREA
Total Concentration
Range
low
Chemicals of Concern
high
INORGANIC COMPOUNDS
Aluminum. mglkg
Antimony, mglkg
Barium, mglkg
Beryllium,mglkg
Cadmium, uglkg
Chromium mglkg
Chromium (hexavalent). mglkg
Copper. mglkg
Lead.mglkg
Mercury, uglkg
Nickel. mg/kg
Silver, uglkg
Fluoride. mglkg
. Nitrate + Nitrite, mglkg
Cyanide (total). mg/lcg
1.640
11.5
22
1
1.6
2
0.79
4.7
3
0.07
4.7
24
9.2
0.4
1
158.000
461
1.820
5.5
159.000
42.500
9.3
28,600
858
2.400
179
28,100
253
71
34
20
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Septemb~ 19, 1990
extent of contamination appears to be limited to a small area under and around the tanks.
Additional source ar~ for ground water contamination exist in the M3 area, SSB area and
the Chemical Technology Lab area. These are RCRA regulated areas not investigated as part of the
RI. Large amounts of TCA, TCE, DCE, acetone, chromium, and other chemicals have been
released to the ground water. In the M3 area, the ground water has been severely contaminated in
three areas. The most contaminated area is at the north end of the manufacturing building.
Concentrations of TCA up to 2,600,000 ugll have been detected. Other contaminants present include
TCE, DCE, acetone, methylene chloride, and chromium. In this area there is no alluvial ground
water, therefore, all the contamination is located in the bedrock and the bedrock ground water.
The second contaminated area is down gradient of the Evaporation Pond, where levels of
TCA up to 110,000 ugll have been detected. Other chemicals that have been detected include DCE
and chromium. Both bedrock and alluvial ground water hive been contaminated. The Evaporation
Pond is now undergoing RCRA closure under the supervision of CDH.
The third area of contamination is directly down gradient of the Evaporation Pond near the
south end of the manufacturing building. TCE has been detected at concentrations of 150,000 ugll.
TCA and DCE also occur at high levels. There is a source for contamination in this area, but some
of the TCA and DCE may have migrated from the Evaporation Pond. Both alluvial and bedrock
ground water are highly contaminated in this area. The ground water contamination from these three .
source areas is migrating down Filter Gulch towards the Kassler facUity. The contaminated alluvial
ground water is intercepted by the Filter Gulch recovery well system. The contaminated bedrock
ground water is migrating off-site near Filter Gulch. Before the recovery well system was installed,
TCE from these sources was detected in the Kassler area.
,,-
4.3
MOBILITY OF CONTAMINANTS
4.3.1 Ground Water
The migration of contaminants in the alluvial ground water is the dominant contaminant
transport process active at the site. High levels of contamination have migrated into the upper
reaches of Dry Gulch. Lesser amounts of contamination continue to migrate downstream intO the
Brush Creek drainage and along the West Branch of Brush C: ::>ek into the South Platte alluvium
around the Kassler facility. The concentration of TCE in the headwaters of Dry Gulch is as high as
67,400 ugll in well GM-ll. About half way down the gulch at well GM-80, the concentration of
TCE drops an order of magnitude to 5,680 ugll. At the point where Dry Gulch intercepts ~e West
21
RE:012-COSOO2\maniD\rocI- 1-49
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September 19, 1990
Branch of Brush Creek, the concentration of TCE is about 1,800 ugll. Above the West Branch of
. Brush Creek recovery well system, the concentration of TCE ranges from 36 ugll to 260 ugll.
Below the Brush Creek ground water recovery well system, the TCE concentration in the
ground water has dropped with time. Before operation of the recovery well system, GM-69 had
TCE concentrations as high as 71 ugll. After nearly 1.5 years of operation, the concentration in the
ground water had dropped below the detection limit. All the other wells down gradient of the West
Branch of Brush Creek recovery well system have also shown decreases in the level pf TCE
contamination.
NDMA and chromium are tWo cont~minants of concern that have migration characteristics
different from TCE. NDMA is very soluble in water; therefore the speed at which it will move
through the system is dependent upon the ground water velocity. Tbe behavior of chromium is made
more complicated by the different solubilities of trivalent chromium (Cr+') and hexavalent chromium
(Cr+'). Cr+' is much more soluble in water therefore it is much more mobile. Cr+' is not very
,soluble, therefore it is not very mobile. Most of the chromium detected at the Inactive Site is Cr +'.
Although there is contamination in the bedrock, the Cretaceous age Graneros Shale,
Greenhorn Limestone, Carlisle Shale, Niobrara Formation and Pierre Shale form a layer of very low
hydraulic conductivity over 6,300 feet thick. The thickness and impermeability of this sequence will
prevent any contaminated ground water in the bedrock formations that suberop under the MMAG site
from impacting the utilized aquifers in the Denver Basin.
4.3.2 Surface Water and Sediments
Samples have been collected for chemical analysis during the RI from the following surface
water bodies:
.
.
.
.
.
Brush Creek (both branches and Lower Brush Creek)
Filter Gulch
Last Chance Ditch
South Platte River
Lariat Gulch
Surface-water CODtamin~tion has been directed in both branches of Brush Creek. On the East
Branch of Brush Creek, the majority of the contamination appears to be limited to tWo reaches. Tbe
first is from the U.S. Air Force property boundary to directly upstream of the Rifle Range Landfill '
where TCE, cis-I,2-DCE, trans-l~2-DCE and TCA have been detected at maximum concentrations
RE:012~001\martiD\rod.l"'9
22
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September 19. 1990
of S7"ug/l. 5.2 ug/l. 9.7 uln and 5.1 uln. respectively. '!be secoDd is located directly east of the
SSB facUity. TCE is the only organic CODt2miftSllnt fouDd in this portion of Brush Creek with
concentrations ranging from 14 ugn to 31 uln (Geraghty & Mmer, 1990).
Stream-flow rates and ground water flow directions indicated that both these reaches
consistently exhibit gaining conditions and that CODtaminated ground water is discharging to the
stream. In addition, the presence of these contaminants upstream of the property boundary indicate a
source is also located on the U.S. Air Force property (Geraghty & Mmer, 1990).
On the West Branch of Brush Creek there are three areas of surface-water contamination.
Surface water quality has been impacted near the confluence of the West Branch of Brush Creek and
the dry gulch that trends southeast from the Inactive Site area. Ground water migrating down the
dry gulch, through alluvium overlying the Fountain Formation, surfaces at seeps approximately 50
feet above the confluence. Samples collected at the seeps exhibited ci~-1 ,2-DCE and vinyl chloride
concentrations ranging from 5.5 ugn to 27 ugn, and from 3.4 ugn to 34 ugn, respectively.
Low levels of TCE have also been detected adjacent to the Lower Brush Creek Recovery
system and approximately 500 feet upstream of the property boundary. No organic contaminants
have been detected at stations located downstream of the confluence on Lower Brush Creek.
Stream sediments were sampled on both the West and East Branches of Brush Creek and
only toluene was detected at one location near the Inertial Guidance Lab at a concentration of S9S
ugn. .
'!be relatively low concentrations of inorganic compounds in ground water between the
Inactive Site and the upper West Branch of Brush Creek, and the evidence that Brush Creek is a
losing stream along this reach suggest that previous activities at the Inactive Site have not impacted
the inorganic chemical .quality of the stream s~iments of the West Branch of Brush Creek.
Along the East Branch of Brush Creek, bis (2~ylhexyJ) phthalate was detected (2,750 ugll)
in the stream sediments adjacent to the Rifle Range Landfill (Geraghty & Miller, 1987e). An
increase in the concentrations of inorganic chemicals such as chromium (total and hexavalent), iron.
lead, fluoride, total kjeldahl nitrogen (TKN), sulfate, copper, nitrate/nitrite, phosphorus, aluminum.
and zinc in sediment samples collected at surface water stations adjacent to and just downstream of
the Rifle Range Landfill appears to reflect an impact to stream sediment quality from the Rifle Range
Landfill (Geraghty & Mmer, 1990).
23
RE:012~\m8rtia\rod-1""9
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September 19, 1990
. Sediment samples were collected in the lower portion of the West Branch of Brush Creek and
along Lower Brush Creek, and c.-<:a petroleum hydrocarbons (26.0 mgIl) were detected in one
sample. Fluoranthene (2,390 ugll) and pyrene (2,430 ugll) were also detected in one sample and
may reflect the impact on the creek from storm drains which divert runoff from a nearby parking lot
(Geraghty & Miller, 1990).
TCE is the primary organic contaminant detected in Filter Gulch surface water. Other
organic contaminants which have also been detected in Filter Gulch are:
Parameter
Ranl!e of Concentration (Ul!/l)
1, 1, I-trich1oroetbane
cis-l,2-dich1oroetbene
1, I-dichloroethane
l,l-dichloroetbene
bromoform
TCE
vinyl chloride
ND-68
ND-116
ND-273
ND-7.1
ND-S
ND-13S
ND-2.7
Five sediment samples were collected in Filter Gulch. VOCs were not detected in any of the
sediment samples nor were there any inorganic constituents above the established background range.
No organic compounds have been detected in samples from Last Chance Ditch during the RI.
. However, ground water seeps in Last Chance Ditch show low level organic contaminants.
Surface water quality samples collected from the South Platte River at the intake of DWD
conduit # 20, located approximately three miles upstream of the Kassler Treatment Plant, were only
found to contain the common laboratory contaminant bis (2-etbylhexyl) phthalate (24 ugll). The
reported presence of this chemical is attributable to a laboratory bias. Additional samples collected
from the South Platte River at various locations in the Kassler area by MMAG, EPA and DWD
during 1983 and 1985 were free of detectable organic compounds.
No organic compounds have been detected in surface water samples collected from Lariat
Gulch. Cr+' was detected during a March 1987 sampling round at the method detection limit (0.01
mgll) from a sample collected approximately 5,000 feet downstream of the northern boundary of the
U.S. Air Force property.
Organic compoun~s have been detected at a seep on the hillside approximately 300 feet north
of the Propulsion Research Lab (PRL). TCE and cis-l,2-DCE were detected at concentrations of
338 ugll and 16 ugll, respectively. Data developed during the ongoing IRP at the U.S. Air Force
24
RE:Ol1~\maniD\rod.1-49
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September 19. 1990
facility indicate that this seep is fed by ground water in the bedrock (Foundation Formation) and is
not directly related to conditions in the saturated alluvium at the PRL (Geraghty & Miller. 1990).
4.4
MODELLING OF CONTAMINANT MIGRATION
A ground-water cont~min:ntt transport model was developed for the MMAG site to predict
the concentration of the major contaminants of concern at several exposure points for which a risk
assessment was performed (see Section S.O). Exposure point concentrations were predicted for as
much as 100 years into the future (1989 to 2089). First. the ground water flow model was calibrated
to the water levels and volumetric flow rates at the site. Output from the flow model was then used
as input to a chemical transport model which predicted the migration of contaminants at the MMAG
facility between bedrock. alluvium, and surface waters. As an approximation of the uncertainty
associated with the model predictions. simulations were run which used "upper bound" chemical
concentrations at the contaminant sources to predict maximum plausibl~ exposure point concentra-
tions.
The ground water flow model of the MMAG facility is based upon the U.S. Geological
Survey (USGS) computer program for the simulation of ~ee-dimensional ground water flow
(Trescott and Larson. 1976). The chemical transport model was prepared by S.S. Papadopulos &
Associates (SSP&A. 1989).
r
Eight source areas were considered in the contaminant transport modeling: the Evaporation
Pond; the Manufacturing Building and associated facilities in the M3 area; the Space Support
Building area; the Inactive Site; the Rifle Range Landfill; the General Purpose Lab (GPL); the
Chemical Technologies Lab (CTL); the U.S. Air Force properties upgradieDt of the CTL; and the
U.S. Air Force properties upgradient of the MMAG facility along the East Branch of Brush Creek.
Results of the contaminant transport modelling indicated that most of the TCE observed in ' .
the alluvial and bedrock ground water and the surface streams can be explained by migration from
the Inactive Site and the M3 areas at a constant rate. In Filter Gulch the TCE distribution was best
matched when a constant TCE concentration of 1.200 parts per billion (PPb) was assumed at the M3
area. This is somewhat lower than the esthnated average source concentration of 1.800 ppb. In Dry
Gulch. West Branch of Brush Creek, and Brush Creek, the TCE distribution was almost completely
explained by migration from the Inactive Site.
.
There was considerable debate over developing estimates of the uncertainty associated with
the model results. EPA determined that developing an accurate probability distribution for "xposure
2S
RE:012~\maniD\rod-1-49
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September 19, 1990
point concentrations was not possible given the large number of parameters involved in the model.
Instead, it was qreed that estimates would be made for the 8upper bound8 exposure point concentra-
tions. These upper bound values were considered the plausible maximum aqueous concentrationS at
the exposure points. The upper bound concentration at a well was defined as the mean concentration
plus two standard deviations.
"
Exposure points for which the upper bound concentrations were evaluated included ground
water wells on- and off-site, surface water. in Brush Creek, the South Platte and soils on-site
assuming residential and industrial exposure scenarios. The results of the risk assessment describe
the risk associated with these points of exposure.
Evaluation or Ground Water Remedial Alternatives
The four ground water alternatives presented in Sections 6.6 ~ougb 6.9 were evaluated
using the model to determine the amount of time required for ground water restoration. The model
assumed that all sources were removed or remediated. The remedial time frames for ground water
restoration for each alternative are as follows: .
Alternative
GW-l
Restoration Time
More than 130 years off-sitel70 years on-site
GW-2
GW:-3
130 years on-site/more than S years off-site
4S years on-site/more than S years off-site
GW-4
4S years on-sitelmore than S years off-site
In simulating these remedial alternatives, the calibrated model was modified so that the
alluvial ground water was completely removed at these points. The water w~ then reinjected into
the surface water model segments corresponding to the location where outflow from the treatment
system enterS Brush Creek.
Contaminant Transport Modelling at the Chem Mill, SSB, and Evaporation Pond
Source areas affecting ground water which were not part of the RIlFS but are currently
managed under RCRA authority, were evaluated as part of a site-wide ground water remediation
. plan. Modelling was used to assist in the selection of appropriate systems which were added to the
ground water alternatives in the FS.
26
RE:012-COfOO1\manio\rod-1-49
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September 19, 1990
. Corrective action measures at the Chem MDt, SSB, and Evaporation Pond areas were
evaluated usinl coupled ground water flow and cont2min'nt transpon models as d~cribed for the site
wide model. In the Evaporation Pond area the same site wide models described previously were
used to evaluate contaminant transpon. At the Chem MiJI and SSB area, additional localized models
were developed in a manner analogous to the overall site model. Ground water transpon was
estimated by calibrating the USGS's three-dimensional modular flow program developed by
McDonald and Harbaugh (1988) and contaminant transpon was determined with a three-dimensional
transpon code developed by. SSP&A.
ContaminJfttS simulated in the Chem MiJI area include TCE, TCA, and hexavalent
chromium. Contaminant transpon modeling of the Chem MiJI area simulated potential corrective
measures. These included (1) perforation and withdrawal of ground water from all four sumps in the
Chem MiJI basement and (2) perforation and ground water withdrawal from all four sumps (as in 1)
and pumpage of ground water from 9 wells located in areas of ground _water contamination.
Model simulations indicated that pumping water from the sumps is an effective method of
removing TCE and TCA from the ground water. If a pumping alternative is used, TCA is predicted
to decrease below the maximum contaminant level (MCL) In less than 8 years. Additional wells are
required to achieve comparable removal of chromium from the vicinity of the Hydrostatic Test Tank.
Hexavalent chromium is not easily removed due to its limited mobility in the ground water as
compared to the VOCs.
Modelling at the SSB simulated a scenario involving pumping of ground water from seven
wells in the area all of which show signs of ground water contamination. The total flow to the seven
wells in the remedial alternative was less than 0.1 gpm. Furthermore, based upon monitoring data,
the model predicted the acetone concentrations would drop below 2,400 ppb (the lW risk level) in
10 years. Addition of extraction wells would DOt appreciably alter this outcome with respect to the
time required to achieve the cleanup level.
Simulations of remedial alternatives in the Evaporation Pond area considered the transpon of
TCA. Modelling results indicated that TCA concentrations in the aI.luviai ground water would be
decreased significantly in 10 years under a scenario of source control by fixation and capping.
Source control does not have a significant impact ,on bedrock TCA concentrations in this same time
frame due to the lower ground water velocity ~
27
RE:012-c08002\mutin\rod-1-49
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September 19, 1990
5.0 SUMMARy OF SITE IUSK
A Public Health Evaluation (PHE) and Ecological Assessment (EA) were performed for the
MMAG site by Clement Associates, Inc. (CAl, 1990). The information presented in this section is
summarized from that report. The purpose of the PRE and EA was to evaluate the risk to human
health and the environmental impactS which might be associated with the MMAG site under current
or potential future conditions of land use. The PHE and EA constitute a baseline risk assessment.
They are based on the assumption that no remedial action or mitigation procedures are instituted or
in place that might lower the concentrations or reduce the effects of contamination identified in
various media on the site. The risks associated with the site were evaluated to facilitate selection of
remedial actions at the site.
5.1
CONTAMINANT IDENTIFICATION INFORMATION
-
Contaminant concentrations used in the risk assessment were of two types:
1.
2.
Validated sampling data
Data generated by computer modelling that resulted in estim!lted chemical
concentrations at locations dOWDStteam from known sources for future and present
conditions
These data were used to identify the media and conuminants of concern, to calculate the associated
health risks, and to evaluate potential environmental effects.
5.1.1 Media or Concern
Three media of concern were identified because they could be pathways of exposure to
contantin~ts originating on the MMAG site: soil, surface water, and ground water. The basis for
selection of these media was the presence of significant concentrations of contaminants and the
potential for human exposure and environmental effects associated with these concentrations.
Air was not selected as a media of concern because air monitoring data showed no inorganic
contamination and insignificant contamination (low concentrations detected only once) of VOCS.
Transport of non-volatile compounds by airborne dusts was not considered in the risk assessment
except for the case of on-site construction workers involved in activities that disturb subsurface soil
for limited periods of time.
RE:012-c0&002\maJW1\rod-J -49
28
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September 19. 1990
Sediment was not considered a medium of concern because samplina data indicated no
sipificant coDt2lninadon within that medium.
5.1.2 Contaminants or Concern in Each Medium
Chemicals of potential concern for the risk assessment were selected by a process of
elimination. Sampling data for each chemical were scrutinized and compared to selection criteria.
The following criteria were used to eliminAte a detected contamin:ant from further consideration:
.
The contaminant was not specifically identified in the sampling results but was
reported only as a chemical class.
. No toxicity criteria exist with which to evaluate the health or environmental effects of
the identified chemical.
.
.
The chemical concentration was not above local or regional background
concentrations.
.
The chemical was detected with a frequency of less than S percent or only once. and
was not detected frequently above background in related media.
The sampling data did not meet Level 4 criteria for Data Quality Objectives (DQOs)
as defined by EPA (EPA. 1987) and the chemical was DOt detected above background
levels in related media.
.
In addition. only dissolved metals were considered in ground water (that is only the metals
detected in filtered ground water samples) with the exception of hexavalent chromium. Total metals
(metals detected in unfiltered samples) were considered in selection of chemicals of concern for
surface water. Radioactive parameters were not considered because of the proximity of uranium-
bearing geological zones and minimal historic use of radioactive compounds on the site.
Chemicals of potential concern were identified separately in each of 1.1 different geographic
areas for ground water, 9 different areas of surface flow for surface water. and 9 geographic areas
for soil contamination. Up to 53 chemicals were determined to be of potential concern in each of
these areas. with the largest number being present in the soils and ground water in the Inactive Site
area. Classes of chemicals designated to be of concern included:
.
Chlorinated aliphatic organic compounds accounted for most of the chemicals of
concern considered and included TCE, tetrachloroethylene. 1.1.I-TCA and a suite of
transformation products including vinyl chloride
Aromatic compounds including benZene. toluene. phenols. and xylenes
.
.
Hydrazines and the transformation product NDMA
29
RE:OI2~\maniD\rocI-l""9
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.
.
September 19. 1990
Polycyclic aromatic hydrocarbons (P AH) including beozol(a)pyrene
Polycb1orinated biphenyls (PCBa)
.
inorganic compounds including fluoride. nitrates ~d niuites. cyanide. and at least 16
metals including hexavalent chromium. arsenic. lead, cadmium, and beryllium
The complete listing of chemicals of concern for each media in each geographic area is provided in
Tables 2-5 through 2-8 in the PHE (CAI, 1990).
5.1.3 Concentrations of Chemiaals
In general, concentrations of chemic:als are highest in ground water and soil and lowest in
surface water on the site. ~ the 11 geographic areas on the site that were investigated. the most
contaminated areas both in numbers of contaminants and concentrations of contaminants are the
Inactive Site and the M3 area. The Filter Gulch area is also associated with relatively more
contaminants or higher concentrations of contaminants than other site areas.
Concentrations of organic contaminants in ground water were generally in the ppb range but
a large number of organic and inorganic contamilu~nts were found in parts per million (ppm)
concentrations in at least one geographic area including:
.
The ketones acetone and 2-butanone
.
The chlorinated aliphatic compounds methylene chloride, TCE, tetrachloroethylene,
1,1,1- TCA and the transformation products cis- and trans-l,2-DCE, 1, I-DCE. and
1 ,I-DCA
The aromatic compounds toluene and total xylenes
.
.
The nitrogen-containing organic compound monomethyl hydrazine
Inorganic compounds including the metals hexavalent chromium, total chromium,
arsenic, iron, manganese, mercury, silver, copper, aluminum, the halogen fluoride.
the nitrogen-containing inorganic compounds nitrate and nitrite, and ammonia
.
Of the organic contaminants, TCE contamination of ground water was the highest and most
widespread: TCE was detected in nine ground water study areas and was found in ppm
concentrations in five ground water study areas on-site. Related chlorinated compounds and
transformation products were also widespread, although not generally in such relatively high
concentrations.
RE:012.c0B002\mar\iD\rocI-l-49
30
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September 19, 1990
Hexavalent chromiUm was detected in six study areas although it was eJimin2t"
-------
September 19, 1990
TableS A-12 through A-22of the PHE present the complete results of contaminant concentrations
detected in surface water including the South Platte River sampling results (CAI, 1990).
5.2
EXPOsuRE ASSESSMENT INFORMATION
Human exposure to contamin3ftm of concern identified on the MMAG site were assessed
based on the presence of contaminants in the three primary media of concern (soil, ground water,
and surface water) and the likelihood of human contact with those media by inhalation, ingestion,
and dermal contact. Exposures to DOn-human species were evaluated based on chemic:al
concentrations in soil and surface water and the likelihood of direct contact with these contaminants
by wildlife or plant species. EPA required the evaluation of domestic use of ground water on-site as
a reasonable maximum exposure scenario. .
5.2.1 Exposure Pathways
For humans, the following major pathways were evaluated:
.
Ingestion of venison or fish that had contacted site contaminants in soils and surface
water on or proximate to the MMAG site
Direct contact with contaminated soils in different geographic areas on-site by
incidental ingestion, inhalation, and dermal absorption
.
.
Domestic use of surface or ground water at various sampled exposure points resulting
in exposure by ingestion and inhalation of cont2minaDts volatilizing from water
during use .
Nineteen potential pathways were initially considered but only 11 were evaluated as likely to be
complete. All pathways considered are tabulated in Tables 4-2 and 4-6 of the PHE (CAl, 1990).
. .
For wildlife and plants the following exposure pathways were identified:
.
Direct contact with contaminants in soil by inhalation, ingestion, aerial deposition and
absorption (such as deposition on plants), or dermal exposure (such as during
burrowing behavior)
Direct contact with contaminants in surface water by ingestion, by dermal absorption
during bathing or swimming, or for fish during respiration through gills
.
.
Direct contact with contaminated sediments by wading animals or birds, or by
ingestion by bottom-feeding invertebrates or fish
Indirect contact with contaminants originating on the MMAG site by ingestion of
contaminated prey or vegetation
RE:012~\martin\rod-l~9
32
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September 19, 1990
Most 'of these pathways were considered only qualitatively in the assessment because data are lacking
for quantitative evaluation.
5.2.2 Potential Exposed. Populations
Potentially exposed human populations were identified to include the following:
.
Deer hunters on the site and persons fishing in the nearby South Platte River or the
Division of Wildlife ponds
Workers at the MMAG site working at specific outdoor locations
<,
.
.
Domestic users of water from the Chatfield Reservoir downstream from the site
.
Hypothetical residents living on-site
Animal and plant populations potentially exposed include:
.
Rare, threatened, or endangered species including a plant rare only in Colorado, the
annual threeawn, and two Federally-listed endangered species: the bald eagle and the
peregrine falcon .
Plant, terrestrial animal, and bird species associated with the variety of habitats on or
proximate to the site that range from grasslands to mountain habitats and include
riparian habitats along the South Platte River and the Chatfield Reservoir
.
.
Aquatic species in the South Platte River and the Chatfield Reservoir including game
fish and the.populations of species that support them
The 'populations of fish, invertebrate, and plant species that may live or range into
the on-site streams of Brush Creek, Dry Creek, Filter Gulch, and Lariat Gulch some
of which have perennial flow in certain portions of their courses through and off the
site
.
5.2.3 Monitoring or ModelUng Data and Assumptions Used to Characterize Exposure Point
Concentrations .
Both monitoring and modelling data were used to estimate exposure concentrations.
Monitoring data from on-site soil, surface water, ground water sampling, and air monitoring data
were used for most on-site exposure points. Off-site sampling data that was collected included
surface water samples collected from the Kassler area, the South Platte River, and the Last Chance
Ditch. Geometric mean and maximum values were used to evaluate the average and plausible
maximum exposures, respectively.
33
RE:012~\mania\rod-l"'9
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September 19, 1990
. The O1igration of CO!Jt2min2nts in ground water was modelled from seven major source areas
assuming linear adsorption. Co~minmt concentrations were estim!ated by modelling for off-site
exposure points and for some ground water points on-site. For modelling purposes, the two ground
water extraction and treatment systems currently operating were assumed to not be in operation.
Organic compounds were primarily assumed to move at the linear velocity of water while retardation
coefficients were used to model the movement of inorganic compounds and metals.
The volatilization of chemicals from surface water was modelled assuming exponential decay
of ~ncentrations. The volatile organic transfer coefficient was estimated to be 0.4 based on-site-
specific data. Volatilization of contaminants from soil was predicted based on chemical-specific
vapor pressure and/or Henry's Law constants. Emissions factors and a simple box model were used
to estimate contaminant concentrations in air as a result of soil-disturbing activities such as
construction.
Concentrations of chemicals in the Chatfield Reservoir were estimated based on predicted
concentrations in the South Platte River multiplied by 0.85 to account for the contribution of other
sources to the reservoir. River concentrations were based on the estimated location where all
chemical contaminmts from the site would have discharged.
Contaminant concentrations in venison were estimated using modified transfer coefficients for
uptake of chemicals in beef cattle. Bioconcentration factors in fish were based on literature values or
were estimated if not in the published literature. .
For a complete account of data and assumptions used, the PHE should be consulted (CAI,
1990).
5.2.4 Assumptions or ~posure Frequency and Duration
The assumptionS regarding exposure frequency and duration for the various pathways
evaluated are presented in Table 5-1 of this repone .
5.3 . CURRENT AND FtJ'1'VRE USE SCENARIOS
5.3.1 Assumptions
The baseline risk assessment relied primarily on standard assumptions of exposure available
in the Exposure Factors Handbook (1988). Assumptions concerning average body weight,
RE:012-C01OO1\maJtiD\rod-l-49
34
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TABLE 5-1 September 19, H
Assumptions ot Exposure Frequency ami Duration Used
tor Baseline Risk Assessment or MMAG Site Contaminants
Exposure Frequency Exposure Duration
Plausible Plausible
Exposed Population Routes of Exposure Average Maximum Average Maximum
Current Conditions
Deer hunters Ingestion of venison 3 4 9yr 30 yr
times/wk times/wk
Persons fishing in Ingestion of fish Daily(o) Daily 9yr 30 yr
river or ponds nearby
Domestic water users Ingestion of water Daily - Daily 9~) 30 yr
Inhalation during showering Daily Daily 9yr 30 yr
Future condi' :m
On-site MMAu Dermal contact with soil 180 d/yr 180 d/yr lyr 3yr
workers
Incidental ingestion of soil 180 d/yr 180 d/yr lyr 3yr
Inhalation of contaminants 180 d/yr 180 d/yr lyr 3yr
in soil(C)
On-site construction Dermal contact with soil 30 d 30 d 6wk 6 wk
workers
Incidental ingestion of soil 30 d 30 d 6wk 6 wk
Inhalation of contaminants 30 d 30 d 6wk 6 wk:
in soil
Future residents Dermal contact with soil 80 dIyr 200 d/yr 9yr 30 yr
Incidental ingestion of soil 80 dlyr 200 d/yr 9yr 30 yr
Dermal contact with surface 7 dlyr!" 7 d/yr 9yr 15 yr
water
Use of on-site ground water Daily Daily 9yr 30 yr
(mgestion and inhalation)
Use of on-site surface water Daily Daily 9yr 30 yr
(ingestion and inhalation)
. 3S
RE:Ol1~\martiD\rodlbl.5
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September 19, 1990
TABLE 5-1.
Assumptions of Exposure Frequency and Duration Used for
Baseline Risk Assrssment of MMAG Site Contaminants (Concluded)
Exposure Frequency Exposure Duration
Plausible Plausible
Exposed Population Routes of Exposure Average Maximum Average Maximum
Future residents (cont.) Use of off-site ground water Daily Daily 9yr 30 yr
u (ingestion and inhalation)
Use of off-site surface water Daily Daily 9yr 30 yr
(ingestion and inhalation)
Use of Kassler underground Daily . Daily 9yr 30 yr
storage tank water
Ingestion of fish with. Daily(a) Daily 9yr 30 yr
Kassler system operating
(a) Daily consumption of fish was assumed because the consumption rate was based on an annual average
divided by the number of days in a year. . .
(II) For non-carcinogens only the 9 year case resulted in the greatest calculated exposure, so it was
considered the plausible maximum case and the 30 year case was considered the average case.
(e) For inhalation, exposure was assumed to occur for 4 hours per day for each of the 180 days per year
~ For children wading in on-site streams, exposure was assumed to last for 2.6 hours per day from ages 3
through 12 or 3 through 18.
. 36
RE:012.a)8()()1\martiD\rodIbI.5-1 \ale
-------
September 19, 1990
consumption rates for water and fish, showering times, inhalation rates, rates of incidental ingestion
of soil, body surface area, average lifetime, time spent swimmil\g or wading, and residence duration
were all based on data from the handbook. Other published literature or professional judgement
were used when data were not available in the handbook. The PRE presents the assumptions used
for exposure in Chapter 5 and in Appendix C (CAI, 1990).
5.3.2 Current Use Scenario
The exposed populations considered in the current use scenario are listed in Table 5-1.
Access to the site is restricted under current conditions.
5.3.3 Future Use Scenario
The exposed populations considered in the future use scenario are listed in Table 5-1.
Currently unused portions of the site are assumed to be storage areas resulting in employee exposure
to high contamination. An alternative assumption included the site being developed for residential
use, exposing construction workers to subsurface soils and residents to contaminated media. The
Kassler system was assumed to resume operation in order to evaluate its effect on contaminants
reaching the South Platte River.
5.4
TOXICITY ASSESSMENT INFORMATION
5.4.1 Slope Factors
Slope factors (SF) have been developed by the EPA Carcinogenic Assessment Group (CAG)
for estimating excess lifetime cancer risks associated with exposure to potentially carcinogenic
chemicals. SFs, which are expressed in units of (mglkg/day)"', are multiplied by the estimated intake
of a potential carcinogen, in mglkg/day, to provide an upper bound estimate of the excess lifetime
cancer risk associated with exposure at that intake level. The term .upper bound. reflects the
conservative estimate of risks calculated from the SF. Use of this approach makes underestimating
the actual cancer risk highly unlikely. SFs are derived from the results of human epidemiological
studies or chronic animal bioassays to which animal-to-buman extrapolation and uncertainty factors
have been applied. SFs for the major contaminants at the MMAG site are presented in Table 5-2.
37
RE:012..cM002'-rtia\rocl-1-49
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September 19, 1990
TABLE 5-2.
SLOPE FAcroUw USED IN THE BASELINE lUSK ASSESSMENT FOR MMAG SITE
Chemical
Slope Factor (mglkg/day)"'
W eight~f-Evidence
Classification~'
Benzene
QW
0.029
1,1 - Dichloroethane
1,1 - Dichloroethylene
0.091
0.6
Methylene chloride
N - nitrosodimethylamine
0.0075
51
Polychlorinated bipheyls
Polycyclic aromatic hydrocarbons
7.7
11.5
Tetrachloroethylene
Trichloroethylene
0.051
0.011
Unsymmetrical dimethylhydrazine
Vinyl chloride
1.88
2.3
Cadmium
Chromium, hexavalent
Lead
Inhalation
0.029
A
B2
- ,
1.2
0.014
C
B2
51
7.7
B2
B2
6.1
0.0033
B2
B2
0.0046
B2
0.295
6.1
B2
A
41
Bl
A
B2
c.J Slope factors are only presented for contaminants classified as to carcinogenicity, and that
contributed significantly to MMAG site contamination as determined by the following criteria:
concentration exceeded a Federal Standard andlor the contaminant contributed to a cancer risk of
> 1 x lW or hazard index> 1 in the MMAG baseline risk assessment. The complete list of
slope factors for chemicals of potential concern can be found in Tables 3-1 and 3-2 in the PHE
(CAl, 1990).
"" Weight~f-Evidence Classes are as follows:
A = Human Carcinogen, sufficient evidence from human epidemiologic studies
B 1 = Probable Human Carcinogen, limited human ~idence and adequate animal evidence
B2 = Probable Human Carcinogen, inadequate human evidence and adequate animal evidence
C = Possible Human Carcinogen, limited animal evidence in the absence of human evidence
D = Not classified as to human carcinogenicity
E = Evidence of noncarcinogenicity
38
RE:OI2.co&P021awtia1roc1lbl.5-2
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September 19. 1990
5.4.2 Reference Dose
Reference doses (RIDs) have been developed by EPA to indicate the potential for adverse
health effects from exposure to chemicals exhibiting noncarcinogenic effects. RIDs. which are
expressed in units of mglkg/day. are estimates of lifetime daily exposure levels for humans.
including sensitive individuals. Estimated intakes' of chemicals from environmental media (such as
the amount of a chemical ingested from contaminated drinking water) can be compared to the RID.
RIDs are derived from human epidemiological studies or animal studies to which uncertainty factors
have been applied (that is. to account for the use of animal data to predict effects on humans).
These uncertainty factors help ensure that the RIDs will not underestimate the potential for adverse
noncarcinogenic effects to occur. RIDs for the major CODtamin:lnts at the MMAG site are presented
in Table 5-3.
5.4.3 Explanation ot Toxicity Intonnation
.
The SFs and RIDs were used to quantitatively characterize the health risk associated with the
CODtamin:lnts of concern. Examination of Tabl~ 5-2 and 5-3 reveals that SFs vary by up to 4 orders
of magnitude (a factor of 10.000) and that RIDs also vary substantially. A large SF indicates that a
low exposure or intake produced carcinogenic effects in the study or studies used to determine the SF
and/or that the uncertainty associated with the carcinogenicity of the chemical is high. A small SF
indicates that at low exposures or intakes the carcinogenic effects were low and/or that the
uncertaintY is low. ' For RIDs. the lower the. RID the greater the potential for adverse effects at low
intakes and/or the higher the uncertainty associated with the RID. ' Generally. high SFs and low
RIDs are associated with chemicals that have shown a high potential for carcinogenic or other
adverse effects. at least in animal studies. As an example. the RID for TCE is relatively low
indicating a high potential for adverse effects to be associated with exposure to this contaminant.
However. the SF for vinyl chloride. a transformation product of TCE. is much higher than the SF
for TCE. indicating that at similar exposures there may be a higher potential for carcinogenic effects
to occur from vinyl chloride than from TCE:
Qualitative information regarding the types of toxicity or carcinogenicity of the 53
compounds of concern were provided in toxicity profiles presented in Appendix B of the PHE.
5.5
RISK CHARACTERIZATION INFORMATION
Risk was characterized for carcinogenic and noncarcinogenic effects that could potentially
result from exposure to chemical contaminants detected on the MMAG site.
39
1tE:011.c08002\martia\rod-1-49
-------
TABLE 5-3.
REFERENCE DOSE'SCAI USED IN TIlE BASELINE RISK ASSESSMENT FOR MMAG sn"E
September 19, 1990
Chemical
-
Reference Dose (mglkg/day)
Q[al Inhalation
1,1 - Dichloroethane 0.1 0.1
1,1 - Dichloroethylene 0.009
Methylen~ chloride 0.06
Polycyclic aromatic hydrocarbons 0.4
Tetrachloroethylene 0.01
1,2,4 - Trichlorobenzene 0.02 0.003
1,1,1 - Trichloroethane 0.09 0.3
Trichloroethylene 0.00735
Ammonia 0.97 0.36
Cadmium 0.001
Chromium, hexavalent 0.005
Chromium, trivalent- 1
Copper 0.037 0.01
Lead 0.0006
10) Only chemicals with established reference doses and which meet the following criteria are
presented: concentration on MMAG site exceeded a Federal Standard or the contaminant
contributed to a cancer risk of > 1 x 1(1' or a hazard index> 1 in the MMAG baseline risk
assessment.
40
RE:012~aaniDlrodlbl.5.3
-------
September 19, 1990
5.5.1. Quantifted Carcinogenic Risks for Each Contaminant of ConC8"D in Each Pathway
Excess lifetime cancer risks are determined by multiplying the intake level with the cancer
slope factor. These risks are probabilities that are generally expressed in scientific notation (that is,
1 x 1~. An excess lifetime cancer risk of 1 x lQ4 indicates that, as a plausible upper bound, an
individual has a one in one million chance of developing cancer as a result of site-related exposure to
a carcinogen over a 7o-year lifetime under the specific exposure conditions at a site.
The carcinogenic risk associated with each of the 53 chemical contaminants of concern for
each pathway and exposure point is presented in Tables E-l through E~ of the PHE (CAI, 1990).
Table S-4 presents a summary of risk information for 14 of the chemicals of concern. Each of the
chemicals in Table S-4 meets the following criteria for inclusion: .
.
The chemical 'has been classified by EPA as a known or suspected carcinogen
The chemical was described in the PHE as contributing to a cancer risk of greater
than or equal to 1 x Ur for at least one exposure pathway.
.
.
The concentration of the chemical exceeded a Federal standard (such as a the MCL
for drinking water) in at least one sampling location at the MMAG
5.5.2 Combined Carcinogenic Effects
The combined risk for exposure to all of the chemicals of concern for a particular pathway
and exposure point are given in Tables 8-1 to 8-4 of the PHE (pp. 8-6 to 8-17, CAI, 1990).
. The only exposure pathway considered for current land use conditions that is associated with
a risk greater than 1 x 1 Q4 according to the assumptions used in the PHE is domestic use of water
from the Chatfield Reservoir, but only for the plausible maximum intake case. The estimated
average intake results in a risk of 5 x lU7. Modelling estimates rather than measured data were used
for calculating these risks. No direct on-site exposures were considered probable.
When future land use conditions were considered, however, on-site exposures through direct
contact with or inhalation of contaminants in soil resulted in the plausible maximum intake producing
a cancer risk of greater than 1 x 1~ in 4 out of 6 scenarios. In only one of these scenarios did the
risk associated with the estimated average intake also exceed 1 x 1~. In all 5 cases the risk was
within the range of 1 x 1~ and 7 x lW, or one in one million to seven in one hundred thousand.
Direct contact with surface water-was not associated with a risk greater than 7 x 1~ for even the
maximum detected concentrations of chemicals in surface water on-site. Except for the inhalation
41
RE:012~\maniD\rod-l~9
-------
TABLE 5-4
Contribution of IndiVidual Chemicals to Cancer Risk ~ 1 :K lr at
Exposure Points for the MMAG Site
September 19, 1990
Maximum Number of
calculated ~sure
risk from pomts Routes and pathways of
MMAG site where risk - exposure associated with
Chemical contamination ~ 1 x 1~ ~ 1 x 1~ risk
Benzene SxU)"' S Future domestic use of ground water on-
site~)
Future domestic use of ground water off-
site'C)
1,l-Dichloroethane 2 x 10"3 16 Future domestic use of ground water on-
site~)
Future domestic use of surface water on-
site
Future domestic use of ground water off-
site'C)
1,l-Dichloroethylene 2 x 10"1 32 Future domestic use of ground water on-
site~l
Future domestic use of surface water on-
site
Future domestic use of ground water off-
site(C' .
Methylene chloride 3 x 10'2 18 Future inhalation of chemicals by workers
from on-site surface soilslC)
Future inhalation of chemicals by workers
from on-site surface subsoil SIC'
Future domestic use of ground water on-
site
Future domestic use of surface water on-
site
Future domestic use of ground water off-
site'c)
N-Nitrosodimethylamine 1 x 10"1 20 Current domestic use of Chatfield
Reservoir water1c)
Future domestic use of ground water on-
site
Furore domestic use of ground water off-
site'C)
Future domestic use of Kassler storage
tank water(C)
Polychlorinated biphenyls 1 x 1~ 3 Future direct contact by workers with
subsurface soils on-site
Furore direct contact by residents with
surface soils on-site
Future domestic use of ground water
on-site
. 42
RE:012-c0s002\maniD\rocIIbl.5-4\alc
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September 19, 1990
TABLE 5..j
Contribution of Individual. Chemicals to Canal' Risk ~ 1 s 1"" at
Exposure Points tor the MMAG Site (Conduded)
Maximum Number of
calculated extK>sure
risk from pomts - Routes and P~;:rs ~f
MMAG Site where risk exposure asSOCI WIth
Chemical contamination 21xUr 2 1 x 1
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September 19, 1990
pathway, these risks were Calculated using measured concentrations of contaminants. Concenttations
of soil comsmiftAftts in air were estimated by computer modelling as described previously.
""
The use of ground water on-site for domestic purposes including ingestion and showering
would be associated with relatively high cancer risks depending on the exposure point. At 11 out of
14 on-site exposure points (80 percent), domestic use of the ground water would be associated with
an upper-bound cancer risk greater than 1 x 1(t (greater than 1 in 10,000) for both the estimated
average intake and plausible maximum intake. Five of the exposure points where the calculated risk
was greater than or equal to 1 x 1(t were alluvial ground water; 6 were ground water points
associated with bedrock formations. Concenttations in alluvial ground water were measured, while
contaminant concentrations in ground water associated with bedrock formations were based on .
modelling estimates. The upperbound cancer risk associated with domestic Use of ground water
ranged from a low of 1 in 100,000 (1 x 10') to a high of 1 in 10 (1 x 101). At 5 of the 14
exposure points (36 percent), the upper-bound cancer risk associated ~ith domestic use of ground
water was estimated to be greater than 1 in 1,000 (1 x 10); 3 of these points were alluvial ground
water points and 2 were ground water points associated with bedrock formations.
c,
The domestic use of surface water on-site was associated with a lower cancer risk that ranged
from a low of 3 x lW for the average intake at one surface water exposure point to 7 x 10' for the
plausible maximum at another surface water location based on measured data.
Domestic use of ground water off-site, was calculated using modelling estimates of site-
. boundary concenttations.. Off-site ground water use was associated with an upper-bound cancer risk
that ranged from 9 in 100,000 for the average case from a Brush Creek well to 8 in 1,000 for the
plausible maximum case from a Filter Gulch well. The average and plausible maximum cases
differed by about .one order of magnitude (a factor of 10). Off-site surface water taken from Brush
Creek, if used domestically, would be associated with a 3 in 100,000 (average case) to 1 in 10,000
(plausible maximum case) upper bound-cancer risk based on modelling estimates of contaminant
concenU"ations.
If the Kassler system were to be put back in operation and water were supplied from the
Kassler underground storage tank without being tteated, the risk would be similar to current use of
the Chatfield Reservoir for both the average and plausible maximum intakes (6 x 10' to 3 x 1
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September 19, 1990
5.5.3 Noncarcinogenic: meets for Eaeh Contaminant In Eaeh Pathway
The relative potential for noncarcinogenic effects to result from exposure to a single
contaminant in a single medium is expressed as the hazard quotiem (HQ) (that is, the ratio of the
estimated intake derived from the contaminant concentration in a given medium to the CODtamin~l1t's
RID). When the HQ exceeds I, the estimated intake exceeds the RID. The potential for adverse
effects to occur increases as the HQ increases above 1. By adding the HQ's for all contaminants
within a medium or across all media to which a given population may reasonably be exposed, the
Hazard Index (HI) can be generated. The HI provides a useful reference point for gauging the
potential significance of multiple contaminant exposures within a single medium or across media.
c>
(>'
The HQs for all contaminants of concern for each pathway and exposure point are presented
in Tables E-l through E-66 of the PHE (CAI, 1990). In Table 5-5 that follows, the noncarcinogenic
hazard information is briefly summarized for 12 contaminants of con~m that were described in the
PHE as contributing to an HI 'of greater than 1 for at least one pathway and location.
5.5.4 Combined Noncarcinogenic: meets
The HIs for the combined exposure to the contaminants of concern for each exposure
pathway and exposure point are presented in Tables 8-1 through 8-4 of the PHE (pp. 8~ through t)-
17, CAI, 1990). No current exposures are estimated to result in an HI that exceeds 1. No direct
on-site exposures were considered probable under current conditioDS.
. Direct contact with or inhalation of contaminants from subsurface soils on-site in the future
were predicted to result in an HI of approximately 6. No other direct contact or inhalation exposures
were predicted to be associated with an HI greater than 1. The inhalation pathway was evaluated
using modelling estimates, rather than measured data.
The domestic: use of ground water on-site was associated with an HI greater than or equal to
1 at 13 out of 14 exposure points (93 percent) for the average case. The average intake resulted in
an HI that ranged from 0.5 to 400 and the HIs ~r the plausible maximum intake ranged from 2 to
800 for all 14 exposure points. The exposure points were divided between 8 alluvial ground water
points, which were actually sampled, and 6 bedrock ground water points were contaminant
concentratioDS were based on modelling estimates. Two out of seven on-site exposure points where
surface water was sampled would be associated with an HI greater than 1 but less than 5, if the
water was used domestically. .
.45
RE:012~\maniD\rod.1-49
-------
TABLE 5-5
Contribution of Individual Chemicals to Hazard Index (ID) > 1 at
Exposure Points tor the MMAG Site
Maximum
calculated Number of
hazard exposure
quotient from points Routes and pa~weds of
MMAG site where HI exposure asSOClat
Chemical contamination exceeds 1 with m > 1'-)
'-'
1, I-Dich1ot:oethane 4 2 Future domestic use of ground water on-
site~)
1,I-Dich1oroethylene 180 5 Future domestic use of ground water on-
site~)
Future domestic use of ground water off-
site(b) .
Methylene chloride 87 4 Future domestic use of ground water on-
site~) -
Tetrachloroethylene 210 2 Future domestic use of ground water on-
site~) .
1,2,4- Trichlorobenzene 15 3 Future inhalation by workers of chemicals
in subsurface soils on-site(\)
Future domestic use of ground water on-
site(b)
Trichloroethane 9S 11 Future domestic use of ground water on-
site~)
Future domestic use of ground water off-
site(e) .
Trichloroethylene 6300 18 Future direct contact with subsurface soils
by workers on-site~)
Future use of ground water on-site
Future domestic use of surface water on-
site~)
Future use of ground water off-site(.)
Ammonia 4 2 Future domestic use of ground water on-
site~)
Future domestic use of surface water on-
site
Cadmium 1.2 1 Future domestic use of ground water on-
site~)
.46
RE:Q11-<:08OO1\maniD\rodlblS-S\alc
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~.
Chemical
. TABLE S-S
Contribution ot Individual Chemicals to Hazard Inder (ID) > 1 at
Exposure Points tor the MMAG Site (Concluded)
Maximum
calculated
hazard
quotient from
MMAG site
contamination
Number of
exposure
points
where HI
exceeds 1
Routes and pathways of
exposure associated
with HI > 1
Chromium
Copper
Lead
(0)
2S0(d)
3
110
6tf)
1
5
Future domestic use of ground water on-
site"')
Future domestic use of surface water on-
site
Future domestic use of ground water off-
site(c)
Future domestic use of ground water on-
site"') .
Future direct contact with subsurface soils
by workers on-site
Future domestic use of ground water on-
site"')
Future domestic use of surface water on-
site
Unless otherwise noted, measured concentrations of CODtamin:lnts were used to calculate the HI.
"')
Ground water. from all alluvia and bedrock formations was evaluated. Measured concentrations of
contaminants in alluvial ground water were used to calculate the HI, while modelling estimates of
contaminant concentrations were used to calculate the HI associated with water in bedrock.
Co)
tf)
. Based on modelling estimates rather than measured data.
The HI reponed were listed only as 8chromium8 but the reference dose used was for hexavalent
chromium.
47
RE:012-c0B002\maniD\rodtblS-:'
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September 19, 1990
. Based on modelling results for off-site ground water eXposure points, two out of three
locations would be associated with an HI ranging from 10 (average case) to 70 (plausible maximum
case). The third point would be associated with and HI of 0.8 to 3. Off-site surface water locations
and the Kassler underground storage tank water were associated with HIs less than 1 according to
modelling estimates.
5.5.5 Sources of Uncertainty
Significant sources of uncertainty for any risk assessment include the following:
.
Sampling data may be biased by technical or analytical limitations and models used to
estimate concentrations at unsampled locations require many assumptions that may not
exactly represent site characteristics. .
Toxicity values such as SFs and RfDs may be based on studies that require
extrapOlation from results of animal studies to effectS in humans, extrapolation of
high-ilose exposures to much lower environmental expOsures, and results from
homogenous animal populations to variable human populations with a wide range of
sensitivities .
.
.
Exposure assumptions used to calculate intakes may over- or underestimate actual
exposures for anyone individual.
Therefore, conservative assumptions are used in risk assessment so that the calculated risk will more
likely overestimate the risk than under estimate the risk.
Uncertainties that are specific to this risk assessment include the following:
.
All off-site and some on-site concentrations were based on modelled rather than
measured data
.
No decay or tranSformation of contaminants with time and tranSport were included in
modelling assumptions.
The last point may be particularly important at the MMAG site because concentrations of two
contaminants, vinyl chloride and NDMA, are not known to have been used on the site but that are
known to be tranSformation products of site contaminants shown in the risk assessment to contribute
significantly to the calculated cancer risks.
RE:012-<;08OO1\martin\rod-1-49
48
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September 19, 1990
5.5.6 . Risk Assfssment COnclusions
Chemical contamination at the MMAG site is widespread in soils and ground water. Fifty-
three contaminants of concern were identified in site soils, ground 'water, and surface water.
EPA has established a risk range of 1 x 1~ to 1 x 1
Based upon modeling. date, the plausible maximum intake estimated for the current use of
Chatfield Reservoir water results in an upper bound cancer risk slightly greater than 1 x 1
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September 19. 1990
5.6.1 Critical Habitats .
The brief qualitative evaluation performed did not identify any critical habitats or effects on
critical habitats either on- or off-site.
5.6.2 Endangered or Threatened Species
The brief qualitative evaluation performed identified one bald eagle nesting v.:ithin a 3-mile
radius and one rare plant that may occur on-site. No effects of site contamination on either species
was projected.
6.0 DESCRIPTION OF ALTERNATIVES .
Remedial action alternatives in the feasibility study (FS) report were evaluated in accordance
with the Comprehensive Environmental Response. Compensation. and Liability Act, as amended by
the Superfund Amendments and Reauthorization Act, and the National Contingency Plan. Prior to
evaluating remedial action alternatives, several preliminary evaluations occurred. Remedial action
objectives were identified on the basis of the site characterization results. Response actions and
associated technologies were considered and screened. The technology screening activities were
based on relative effectiveness, implementability, and cost.
Preliminary remedial action alternatives were developed from the rp.maining technology
process options. Alternatives were developed ranging from those eliminating the need for long-term
management, to alternatives involving treatment that would permanently reduce the mobility, toxicity,
or volume of the hazardous substances as their principal element. Containment options were also
developed. During the preliminary remedial action alternatives analysis. several potential options
were dropped.
Eight alternatives for soil remediation and four alternatives for ground water were developed
in the FS (Eder. 1990). Upon completion of the initial screening phase of the FS. the number of
soil alternatives was reduced to six for detailed analysis. The four ground water alternatives were
also retained in the detailed analysis. Each of the retained alternatives is described in this section.
Remedial action objectives developed for the site are designed to address the principal threat
and reduce the risks posed by potential health threats associated with the ground water. The
remedial action objectives are as fellows (clean up goals are described more fully in Section 8.0):
RE:012-C01002\martill\rocl45-99
50
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September 19, 1990
. Reduce the threat posed by the IDactive Site contamination releases to the
environment which impact ground water and surrounding soil and soil contamination
associated with the Chemical Storage Tanks.
1.
2.
Restore the ground water to its beneficial uses by .reducing contjlmin~'1t levels to
within acceptable standards for drinking water.
There are five soil alternatives from S-1 through S-5, and four ground-water alternatives
GW-l to GW-4, presented below. In-situ soil vapor extraction will not be discussed as a separate
alternative because it was developed solely to address coDtamin~tion in the Chemical Storage Tanks
area. It is a component of all the soil alternatives, excluding DO action.
son.. ALTERNATIVES:
S-I:
S-2:
S-3:
S-4:
S-5:
No Action
DewaterlRCRA CapIIn-situ Soil Vapor Extraction
Dewater/Off-site Incineration and Disposal of WastelEx-situ
Stabilization of Backfill and AlluviumlRCRA CaplIn-situ Soil Vapor
Extraction
Dewater/On-site Incineration of BackfIll, Alluvium, and Waste/Off-
site Disposal of Incinerated WastelEx-situ Stabilization of Incinerated
Backfill and AlluviumlRCRA CaplIn-situ Soil Vapor Extraction
Dewater/Off-site Incineration and Disposal of WastefIbermal
Extraction of Backfill and Alluvium/Ex-situ Stabilization of Backfill
and AlluviumlRCRA CapIIn-situ Soil Vapor Extraction
GROUND WATER ALTERNATIVES:
GW-l
GW-2
GW-3
GW-4
No Action
Continued Operation of the Existing Recovery Well Systemffreatment
by Air Stripping, Carbon Adsorption, and Ion ExchangelDischarge to
Brush Creek
Continued Operation of the Existing Recovery Well System!
InstLation of Additional Recovery Well System in Filter Gulch and
Dry Gulch Upgradient from the Existing Recovery Well Systemsl
Treatment by Air Stripping, Carbon Adsorption, Ion Exchange,
and/or UV Photolysis-OxidationIDischarge to Brush Creek.
Continued Operation of the Existing Recovery Well Systemsl
Installation of Additional Recovery Well Systems in Filter Gulch and
Dry Gulch Upgradient from the Existing Recovery Well Systemsl
Addition of a Recovery Well System in the M3 ArealTreatment by
Chemical Reduction, Precipitation, Clarification, Air Stripping,
Carbon Adsorption, Ion Exchange, and/or UV Photolysis-oxidationl
Discharge to Brush Creek
RE:012-COSOO2\marti.n\rod4S-99
51
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September 19, 1990
6.1
ALTERNATIVE 5-1: NO ACI'ION'
In accordance with Section 300.430(e) (6) of the NCP, the DO action alternative must be
considered in the FS. No action also serves as a baseline for comparison of other soil alternatives.
No contaminants or contaminated media are removed or treated by the no action alternative, although
natural attenuation processes are likely to occur. "
No action, as it pertains to the Inactive Site and the Chemical Storage Tank areas, means that
no activities intended to protect human health and the environment, including any remediation, would
be taken. Contaminant migration from the Inactive Site and the Chemical Storage Tank areas would
continue unrestricted.
Ground water monitoring would be conducted to track contaminant migration. No soil
samples would be collected from either area. There would be DO measures to prevent human
exposure to contaminatiOD. A review of the threat to public health and the environment would be
conducted at least every 5 years.
6.2
ALTERNATIVE 5-2: DEWATER/RCRA CAPIIN-sITU SOIL VAPOR EXTRACTION
The objectives of Alternative S-2 would be to reduce the potential for direct human contact
with the Inactive Site soils, reduce infiltration of precipitation through the Inactive site ponds,
remove perched water from the ponds, and remove volatile organic contaminants (VOCs) from the
Chemical Storage Tank area. No treatment of waste, backfill, or contaminated alluvium would occur
at the Inactive Site.
The area covering the Inactive Site and the area adjacent to it would be regraded to divert
storm water run~n and enhance storm water run~ff. The Inactive Site ponds are located on a
topographic high; therefore, storm water flow would be diverted into the East Branch of Brush Creek
drainage for flow to the north and the West Branch of Brush CreekIDry Gulch drainage for flow to
the south.
RE:012.coSOO2\martiD\rocI4S-99
52
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September 19. 1990 .
. A seri~ of wellpoints would be installed in the perched zones of the Inactive Site to extract
water. The water would be temporarily sto~ed in holding taDks and either trucked. pumped. or
gravity fed to the MMAG's IWTP. The treated water would be discharged in accordance with
MMAG's .COPDES permit. The dewatering process would take approximately 2 to 3 months to
complete.
A multi-layered cap is proposed for covering the Inactive Site area. which includes the five
ponds and the area adjacent to the ponds. The cap would be sloped to divert surfa~ flow away
from the ponds.
Ground water monitoring would be conducted to monitor contaminant migration.
The cap would be maintained and no construction would occur on or near the cap. Since
contaminants would remain at the Inactive Site, the site would be monitored and every five years
EP A would review the remediation to assure that human health and the- environment are protected.
In-situ soil vapor extraction would be used to remove VOCs from the Chemical Storage Tank
area subsurface soil. A series of extraction wells connected to a vacuum pump would be installed in
and around the Chemical Storage Tank area such that the cones of influence would extend over the
entire cont2min:lted area. A series of injection wells connected to a blower or vacuum pump would
be placed in and around the Chemical Storage Tank area and used to induce air flow through the soil
to strip and volatilize the VOCS into the air stream. Subsurface air, VOC vapors, and water vapors
would migrate toward the vacuum extraction wells and be removed for collection and treatment.
Approximately 1.3 million gallons of perched water within the ponds would be removed,
treated, and discharged to Brush Creek. Approximately 2,100 r:y of waste, 9,700 r:y of contaminated
backfill, and 14,700 r:y of CODt2min:lted alluvium would be left in-place.
Because both the Inactive Site and Chemical Storage Tank areas are covered, the Inactive
Site by soil and the Chemical Storage Tank area by asphalt, the potential for direct contact exposure
to contaminants is low. The installation of a cap at the Inactive Site would provide added insurance
that the potential for direct human contact would be minimi7ed. In-situ soil vapor extraction would
effectively remove contaminants from the Chemical Storage Tank area so there would be no concern
for exposure. Contaminants in the soil may continue to migrate from the Inactive Site and enter the
ground water. However, infiltration is greatly reduced and contaminant migration is then reduced.
RE:012-c08002\maniD\r0d4S-99
53.
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September 19, 1990
The wcertainty ~ciated with Alternative S-2 are the ability to lower the ground water
table enough to avoid intersecting the coDt.!lmination below the ponds.
Alternative S-2 would comply with RCRA closure and RCRA cap requirements for surface
impoundments and landfills. Air emissions "from the in-situ soil vapor extraetion process would meet
ambient air quality standards. Perched water would be treated to permit discharge limits before
being discharged to Brush Creek.
Alternative S-2 would be implemented in four months.
6.3
ALTERNATIVE S-3: DEWATERIOFF-SITE INCINERATION AND DISPOSAL OF
WASTFJEX-sITU SfABIUZATION OF BACKFILL AND ALLUVIUMIRCRA
CAPIIN-SITV SOIL VAPOR EXTRACTION
Alternative S-3 would be used to reduce CODt:amin:ant migration from the Inactive Site into the
ground water via removal and/or treatment of both organic and inorganic cont2minants. In addition,
the potential for direct human contact would be minimi7ed by the placement of a cap. The RCRA
cap would also reduce infiltration, which would enhance the long-term effectiveness of treatment. At
the Chemical Storage Tank area, 99~ removal of the organic contaminants would be anticipated,
thereby eliminating the Chemical Storage Tank area as a potential source for ground water
coDt:amin:a.tion.
" This alte~ve would begin with the dewatering of the Inactive Site Ponds. After which,
the contamin:ated areas would be excavated and material separated into waste, contaminated soil and
uncontaminated backfill. Additionally, in-situ soil vapor extraction would be employed at the
Chemical Storage Tank area to remove organic chemicals.
A series of wel1points would be installed in the perched zones of the. Inactive Site to extract
water. The water would be temporarily stored in holding tanks and either trucked, pumped, or
gravity fed to MMAG's IWTP. The treated water would be discharged in accordance with MMAG's
COPDES permit. The dewatering process would take approximately 2 to 3 months to complete.
" Excavation and material segregation would require that three stockpile or staging areas be
used: one for the cover material, one for the waste, and one for the bac1cfil1 and alluvium. The
waste material would be loaded onto plastic-lined trucks and transported off-site to a permitted
incineration and landfill facility. ,The backfill and" alluvium would undergo stabilization. The cover
material would be replaced back into the excavation once the stabilization process is complete and all "
RE:012-C01OO1\maniD\rocI45-99
54
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September 19, 1990
stabilized mat~s have been returned to the excavation. ('Ibe cover material would be
UDCOnt~min~ted or contains COl't~min~nts at levels below the action level.)
The area covering and adjacent to the Inactive Site would be regraded to divert storm water
run-on and enhance storm water run-off. The Inactive Site ponds are located on a topographic high;
therefore, flow would be diverted into the East Branch of Brush Creek drainage for flow to the north
and into the West Branch of Brush CreeklDry Gulch drainage for flow to the south.
b
A multi-layered cap is proposed for covering the Inactive Site area, which includes the five
ponds and the area adjacent to the ponds. The cap would be sloped to divert surface flow away
from the ponds.
Ground water monitoring would be conducted to monitor contaminant migration.
The cap would be maintained and no construction would occur 'on or near the cap. Since
cont~minants would remain at the Inactive Site, the site would be reviewed at least every 5 years by
the EP A to assure that human health and the environment are protected. Periodic S year reviews at
the Chemical Storage Tank area' would not be required since the organic contaminants would be
removed from the soil.
In-situ soil vapor extraction used to remove VOCs from the Chemical Storage Tank area
subsurface soil requires a series of extraction wells connected to a vacuum pump be installed in and
around the Chemical Storage Tank area. A series of injec:tion wells connected to a blower or
vacuum pump would be placed in and around the Chemical Storage Tank area and used to induce air
flow through the soil to strip and volatilize the VOCs into the air stream. Subsurface air, VOC
vapors, and water vapors would migrate toward the vacuum extraction wells and be recovered for
collection and tteatment. Air emissions would be monitored, and additional conttols would be
incorporated as necessary. .
Approximately, 2,100 cy of waste would be transported off-site. Approximately 24,400 cy
of CODtamin!llte
-------
September 19, 1990
(skid-mounted) systems .are ivailable. The specific system and additives would be chosen during the
design phase.
MMAG performed bench-scale stabilization and thermal process treatability studies on
Inactive Site pond materials. The treatability studies are discussed in Section 8.0.
The removal of the waste from the ponds and stabilization of the cont2min:ated backfill and
alluvium would signific8ntly reduce the impact of the Inactive Site on ground water cont:amination.
The installation of a RCRA cap at the Inactive Site would provide added insurance that the potential
for direct human contact would be minimi7.ed. In-situ soil vapor extraction would effectively remove
contaminants from the Chemical Storage Tank area. Cont2min!lted soil materials would remain on-
site but the constituents would be less mobile.
The uncertainties associated with Alternative S-3 are the ability- to lower the ground water
table enough to avoid intersecting the ponds. However, reducing infiltration via a cap and in turn
low.ering the ground water table will be effective to some extent. Another uncertainty is the ability
to stabilize organic con~mirnmts. During the stabilization operation, the cont:aminated soils would be
handled several times. FirSt the soil would be excavated, and then stockpiled. It would then
undergo size reduction, and then proceed through the stabilization process, which often undergoes
several temperature fluctuations due to ambient air temperatures, process water temperatures, and
chemical reactions. With each of these activities, some volatilization is likely to occur.
The transport of waste would comply with RCRA, Department of Transportation, and State
regulations. Incineration of the waste would be performed at a RCRA-permitted incineration facility
and would meet all requirements including at least a 99.99 percent destruction of organic
contaminants. Disposal of the treated waste would comply with RCRA standards, including the
LDRs. Stabilization treatment goals would be based upon LDR standards using the Toxicity
Characteristic Leaching Procedure (TCLP). Perched water and wasteWaters generated from the
treatment processes on-site would be treated and discharged according to MMAG's COPDES permit
requirements. All activities, including in-situ soil vapor extraction, would comply with ambient air
quality standards.
Implementation of the Alternative S-3 is estimated to take 18 months.
RE:012~\maniD\r0d4S.99
56
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September 19,1990
6.4 . ALTERNATIVE 804: DEWATERlON-sITE INCINERATION OF BACKFILL,
ALLt1VIUM, AND W ASTE'OFF-sITE DISPOSAL OF INCINERATED RESlDUESI .
EX-sITU STABILIZATION OF INCINERATED BACKFUL AND ALLUVIUMIRCRA
CAPIIN-sITU SOIL VAPOR EXTRACTION' .
. .
The objective of this alternative is to provide long tenD protection of the 'ground water and
human health by removing and treating waste at the Inactive Site Ponds. By destroying the organic
contaminants and stabilizing the inorganic cont.aminants, additional contaminant loading on the
ground water is precluded and potential human exposure is effectively eliminated.
Alternative S-4 incorporates dewatering of the Inactive ponds, excavation and on-site
incineration of waste, backfill, and alluvium from the Inactive Site ponds, off-site disposal of the
incinerated waste in accordance with LDRs, ex-situ stabilization of the backfill and alluvium,
replacement of waste into the excavation, placement of cover material into the excavation, and
placement of a cap over the Inactive Site. In-situ soil vapor extraction would be used for
contaminated soil at the Chemical Storage Tank area..
Alternative S-4 would be implemented in 3.5 to 4 years.
Dewatering would be implemented as described previously. Controls to collect vapors with
integrated vacuum systems during excavation will be evaluated during the design phase.
Since excavation would be required for this alternative and the waste would be disposed of
separately at an off-Itite RCRA landfill, material segregation would. be necessary at the Inactive Site.
It is anticipated that three stockpile or staging areas would be necessary. The waste material would
be incinerated in the on-site incinerator, allowed to cool, then loaded onto plastic-lined trucks and
transported to an off-site landfill. The backfill and alluvium would then be incinerated after
excavation, processed through stabilization and returned to the excavation. The cover material would
be replaced back into the excavation once the stabilization process was complete and all stabilized
materials would be returned to the excavatiOD.
The area covering and adjacent to the Inactive Site would be regraded and capped as
described previously in the other alternatives.
Ground water monitoring would be conducted to monitor contaminant migration.
RE:012-C08002\mutiD\rod4S-99
57,
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September 19, 1990
. .
. The cap would be maintained and construction restticted on or near the cap. Since
CO~minJnts would remain at the Inactive Site, the lite would be monitored and every five years a
review would be conducted to assure that human health and the environment are protected.
As described earlier, in-situ soil vapor extraction would be used to remove VOCs from the
Chemical Storage Tank area subsurface soil.
Because the waste in the Inactive Site ponds is considered a RCRA Listed Hazardous Waste,
the waste must be treated to meet the treatment standards established for RCRA Listed Waste, .
particularly FOOl, F005, and F019. The best demonstrated available teebnology (BDAT) for the
FOOl and FOOS waste is incineration. The BDAT for FOl9 waste is stabilization. The waste,
approximately 2,100 cy, would be incinerated on-site. The residues would be allowed to cool, loaded
onto lined trucks and transported to an off-site landfill. The Inactive Site contains low levels of the
F019 or inorganic contaminants. If the incinerated waste residues did ~ot satisfy the LDR treatment
standards for F019 (inorganic) wastes, they would be stabilized prior to land disposal in a RCRA
Landfill. The incineration residue would be transported to a landfill for stabilization to avoid
transporting the additional 10 to 40 percent volume that would be generated if stabilization was
performed on-site.
The contaminated backfill and alluvium would be incinerated on-site after all waste was
removed and treated. A rotary kiln process is proposed for incineration. Rotary kiln incinerators
are the most widespread, most proven, and most readily available of the incineration processes;
. however, other types of incinerators would be considered during the design phase.
Following on-site incineration, approximately 24,400 cy of backfill and alluvium would be
treated by ex-situ stabilization in order to immobilize inorganic cont:amin:mts. The stabilization
process incorporates the contaminated soil into a matrix with additives such as Portland cement,
water, and proprietary compounds to immobilize the cont:aminants by chemically and physically
binding them in-place.
Stabilization can be performed in an open pit, in concrete trucks, and in fabricated systems
designed specifically for stabilization. Both stationary and mobile systems are available. The
specific system and additives to be used will be determined during the design phase. The stabilized
product would either be replaced directly back into the excavation or placed in forms and allowed to
cure before being place into the excavation.
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~G coDducted bench-scale treatability studies on thermal treatment and stabilization of
Inactive Site PoDd materials. The results of the treatability studies are discussed in Section 8.0.
The removal of the waste from the ponds and incineratiOIt and stabilization of the
'cont~min~ted backfill and alluvium would significantly reduce the impact that the Inactive Site has on
grouDd water contamination. The installation of a cap at the Inactive Site would provide added
assurance that the potential for direct human contact would be minimi7'ed. In-situ soil vapor
extraction would effectively remove contaminants from the Chemical Storage Tank area, so there
would be no concern for exposure. CoQt~minated materials would remain on-site but the constituents
would be immobilized.
Incineration of the waste, backfill, and alluvium would comply with 'or exceed the technical
requirements of RCRA and the Toxic Substances Control Act (I'SCA). The hazardous waste
incineration standards set forth in 40 CPR Parts 264 and 270 specify three major requirements
regarding incinerator performance:
1.
Principal organic hazardous constituents (POHCs) designated in each waste feed must
be destroyed and/or removed to an efficiency (DRE) of 99.99 percent or better; the
DRE for dioxins and PCBs must be 99.9999 percent.
Particulate emissions must not exceed 180 milligrams per dry standard cubic meter
(dsem) corrected to 7 percent oxygen in the stack gas.
2.
3.
Gaseous hydrogen chloride (HCI) emissions must either be controlled to 4 pounds I
hour or less, or be removed with 99 percent efficiency.
The transport of Inactive Site pond waste would comply with RCRA, Department of
Transportation, and State regulations. Disposal of the treated waste would comply with RCRA
standards, including LDRs. Stabilization would achieve immobilization such that contaminants meet
the treatment standards. Perched water and wastewaters generated from the treatment processes on-
site would be treated to meet COPDES permit requirements. All activities, including in-situ soil
vapor extraction, would comply with ambient air quality standards. This alternative satisfies the
SARA preference for treatment.
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6.5
September 19, 1990
. ALTERNATIVE So5: DEW ATERlOFF-sITE INCINERATION AND DISPOSAL OF
W ASTEJTHERMAL EXTRACTION OF BACKFILL AND ALLUVIUMJEX-SITU
SfABILIZATION OF BACKFILL AND ALLUVIUMJRCRA CAPIVAPOR IN-SITU
SO~ VAPOR EXTRACTION
The objec:tives of Alternative S-S are to prevent the further impact from the Inactive Site area
on ground water and Dlinimi7.e the potential for direct human contact with, inhalation of, and
ingestion of contaminants at both areas. This alternative is designed to remove organic contaminants
and immobilize inorganic contaminants at the Inactive Site, reduce infiltration of precipitation through
the Inactive Site pond, and remove organic contaminants from the Chemical Storage Tank area.
Alternative S-S incorporates dewatering of the Inactive Site ponds; excavation, off-site
incineration and disposal of waste in accordance with LDRs; excavation, thermal extraction and,
stabilization of contaminated backfill and alluvium; replacement of treated backf1l1 and alluvium into
the excavation; and capping over the Inactive Site. In-situ soil vapor ~traction would be used to
treat the soil at the Chemical Storage Tank area. In addition, this alternative includes the off-site
incineration and disposal of the residual organic laden sludge from the thermal extraction process and
the off-site incineration and disposal of regeneration of the carbon from the in-situ soil vapor
exttacUon process and the thermal extraction air treatment system.
Alternative S-S would be implemented in 4 years.
The area covering and adjacent to the Inactive Site would be regraded to divert storm water
run-on and enhance storm water run-off. Grading would be accomplished using conventional
coDSttucUon equipment such as front-end loaders and grade-alls. Water ttucks would be used to
minimi7.e dust generation. The Inactive Site ponds are located on a topographic high; therefore, flow
would be diverted into the East Branch of Brush Creek drainage for flow to the north and into the
West Branch of Brush CreekIDry Gulch drainage for flow to the south.
Ground water monitoring would be conducted at both the Inactive Site and the Chemical
Storage Tank area to monitor contamin~t migration from both areas. Monitoring wells would be
placed within the perched zones to verify that infiltration was the source of the perched water and
that the perched zones were not being recharged. The monitoring wells in the Chemical Storage
Tank area would be placed such that the effec:tiveness of in-situ soil vapor extraction could be
monitored. .
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. The cap would be maintained and DO construction would occur on or near the cap. Since
low levels of contaminants would remain at the Inactive Site, the site would be monitored and every
5 years a review would be conducted to assure human health and the environment are protected.
In-situ soil vapor extraction would be used to remove VOCs from the Chemical Storage Tank
area subsurface soil. A series of extraction wells connected to a vacuum pump would be installed in
and around the Chemical Storage Tank area such that the cones of influence would extend over the
entire contaJninated area. A series of injection wells connected to a blower or vacuum pump would
be placed in and around the Chemical Storage Tank area and used to induce air flow through the soil
to strip and volatilize the VOCs into the air stream. Subsurface air, VOC vapors, and water vapors
would migrate toward the vacuum extraction wells in response to the negative pressure gradient
around the well.
"
The contAminated air and vapor would flow to a vaporlliquid s~arator where contaminated
water would be removed. The contaminated water would be treated to meet COPDES limits in
MMAG's IWTP. The contaJnb,ated air stream would be treated to remove VOC concentrations to
. air quality standards. The carbon would be either regenerated or disposed of accordingly. Air
emissions would be monitored and additional controls would be incorporated as necessary.
The waste in the Inactive Site ponds is considered a RCRA Listed Hazardous Waste. The
waste, approximately 2,100 cy, would be loaded onto lined tr.1dcs and transponed to an off-site
incinerator permitted to accept FOOl, FOOS, and F019 listed wastes. The waste would be incinerated
. to comply with the FOOl and FOOS LDR treatment standards. If the incinerated waste residues did
not satisfy the LDR treatment standards for F019 (inorganic) wastes, they would be stabilized prior
to land disposal in a RCRA Landfill.
Approximately 24,400 cy of contaminated backfill and alluvium would be treated by thermal
extraction to remove organic contAminants. Thermal extraction is a low temperature thermal
treatment process which volatilizes organic cont2minAnts from the soil matrix. Operating
temperatures are low, preventing combustion of the organic contAminants and oxidation of the
inorganic contAminants. The process produces an organic-free soil and an off-gas that, when treated,
generates waste water, clean air, and an organically contAminAted sludge.
Following the thermal treatment, approximately 24,400 cy of bacldill and alluvium would be
treated by ex-sito stabilization. ~e stabilization process incorporates the contamin!lted soil into a
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,
matrix with a4ditives such as Portland cement, water, and proprietary compounds to immobilize the
inorganic cont,minants by chemically and physically binding them ini'lace.
Treatability studies on thermal extraetion and stabilization-were performed previously by
MMAG. The results are discussed in Section 8.0.
<-
The removal and incineration of the waste from the ponds and thermal extraction and
stabilization of the cont~minsated backfill and alluvium would significantly reduce the impact that the
InacPve Site has on ground water contsamination. The installation of a multi-layered cap at the
Inactive Site would provide added assurance that the potential for direct human contact would be
minimi7-ed. In-situ soil vapor extraction would effectively remove contsaminants from the Chemical
Storage Tank area so there would be no concern for exposure. Co»tsaminsated materials would
remain on-site would be treated to immobilize hazardous constituents.
The uncertainty associated with Alternative S-S is the ability to remove organic contaminants
and stabilize inorganic compounds to meet LDR treatment standards.
The tranSpOrt of Inactive Site pond waste and thermal extraetion residues would comply with
RCRA, Department of Transportation, and State regulations. Incineration of the waste would be
performed at a RCRA approved incineration facility and would meet all pertinent requirements
including at least a 99.99 percent destruction of organic contaminants. DiSposal of the treated waste
would comply with RCRA standards, including the LDRs. Thermal extraction would remove
organic contaminants, and stabilization would achieve immobilization to prevent contsaminants from
leaching to the ground water. Perched water and wastewaterS generated from the treatment processes
on-site would be treated to meet MMAG's COPDES permit requirements. All activities, including
thermal extraction and in-situ soil vapor extraction, would comply with ambient air quality standards.
6.6
ALTERNATIVE GW-l: NO ACI10N
In accordance with Section 300.430(e)(6) of the NCP, the DO action alternative must be
considered in the FS. The DO action alternative also serves as a baseline for comparison of other
ground water alternatives. No contamin~ts are removed or treated by the DO action alternative,
although natural attenuation processes are likely to occur. Predicting natural attenuation processes is
not teehnological\y possible for most of the contsaminants present in the ground water.
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. No action, as it pertains to ground water contamin:ation, means that no activities intended to
proted human health and the enviromnent, including any remediation, would be taken. The existing
Brush Creek and Filter Gulch ground water extraction and treatment systems would be shut down.
The existing water supply provided by the Denver Water Department could be used to meet current
water demands and future demands from development. Contamin:ated ground water would be
allowed to migrate off-site. .
"
Ground water monitoring would be conducted to track contamin:ant migration from the site
and to continually assess the resulting risks.
Ground water modeling, assuming the source is removed and natural attenuation processes
occur, predicts that ground water restoration time frames required to attain clean up goals are in
excess of 130 years for on-site ground water and in excess of 70 years for off-site ground water.
This alternative does not provide protection against threats to human health or the
environment. The immediate concern with the no action alternative is that environmental degradation
would continue to occur and that the remedial action objective to restore ground water to its .
beneficial use in a reasonable time frame is not achieved.
The ground water, which is a past and a potential source of drinking water, does not meet
. the clean up gQals at the present time.
6.7
ALTERNATIVE GW-2: CONTINUED OPERATION OF THE EXISTING
RECOVERY WELL SYSI'EMSrrREATMENT BY AIR SI'RlPPING, CARBON
ADSORPI10N, AND ION EXCHANGElDISCllARGE TO BRUSH CREEK
The objectives of Alternative GW-2 would be to preclude ground water migration off-site
into the South Platte River Basin and remove organic and inorganic contaminants from the recovered
ground water.
Alternative GW-2 is presently in operation. The Filter Gulch recovery well system was
installed in 1985, and the Lower Brush Creek recovery system was installed in 1987. The Filter
Gulch recovery system consists of 14 recovery wells located approximately 800 feet southeast of the
M3 area on Denver Water Department property. The Brush Creek recovery system consists of three
24-inch diameter recovery wells installed in a gravel backfilled trench located approximately 2,000
feet east of the M3 area.
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. The recovered water is pumped along with MMAG's industrial process waste waters to the
IWTP in the M3 area Where organic and iDor,anic connminAn~ are removed. Currently, the IWTP
treats wastewater by air stripping, carbon adsorption, and a ferrous sulfate reduction processes. The
treated effluent is discharged to Brush Creek MMAG waste water- outfall (COPDES Permit
#00(1511), located approximately 100 feet downstteam of the Brush Creek recovery system.
"
Ground water monitoring would be conducted semiannually to track contAminant migration
from the site and to assess the resulting risks.
An alternative water supply would be provided should the need arise during the
implementation of alternative GW-2.
MMAG has demonstrated that the Filter Gulch and Brush Creek recovery systems provide
effective containment of contaminants by minimizing off-site migration -of alluvial ground water.
The principal environmental concern associated with air stripping is the generation of volatile
organic air emissioDS. The MMAG IWTP is presently operating within its air permit limitations,
which do DOt require additional treatment of the exhaust air stream. If air emission levels are found
to exceed ambient air quality standards or risk-based levels, the air would require further treatment.
Treatment of the exhaust air would be accomplished by capturing organic constinients using vapor
phase carbon adsorption or by destruction in an incinerator. The need for emission controls would
be assessed during the design phase.
All the residues of ground water treatment would be analyzed for contAminant content and
disposed of accordingly. Sludges would most likely be incinerated at an off-site facility prior to
disposal. Spent carbon and ion exchange resins would either be recycled (regenerated), incinerated,
and/or disposed of directly.
The treated effluent exiting the MMAG IWTP would meet the required treatment standards
of MMAG's COPDES permit before being discharged to Brush Creek via the existing outfall.
Ground water modeling indicates that ground water restoration time frames required to attain
clean up goals are approximately 130 years for on-site ground water and in excess of 5 years for off-
site ground water. However, there is some uncertainty in the estimate of ground water restoration
time. The ground water modeling Jt'as conducted using available data on subsurface conditioDS, and
assumptions wece made regarding all the variables. In addition, the model assume that sources of
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contamination are completely removed. Effectively, this means 'little if any remediation occurs on-
site in the highly contaminated areas for an extensive period.
The untreated ground water does not meet the clean up goals at the present time. With the
implementation of alternative GW-2, however, clean up goals would be achieved off-site in a
reasonable time frame. However, contaminant levels in ground water on-site would remain above
MCLs for over 100 years.
"
6.8, ALTERNATIVE GW-3: CONTINUED OPERATION OF THE EXISTING.
RECOVERY WELL SYSTEMSIINSfALLATION OF ADDmONAL RECOVERY
WELL SYSTEMS IN F1LTER GULCH AND DRY GULCH UPG:RADIENT FROM
THE EXISTING RECOVERY WELL SYSTEMSfl'REATMENT BY AIR STRIPPING, .
CARBON ADSORPI10N, ION EXCHANGE, AND/OR UV PHOTOLYSIS-
OXIDA TIONIDISCHARGE TO BRUSH CREEK
The objectives of Alternative. GW-3 would be to preclude contaminant migration off-site and
restore the ground water to beneficial uses by recovering ground water and removing organic and
inorganic contaminants.
Alternative GW-3 is a modification to Alternative GW-2 that incorporates two additional
extraction systems coupled with recharge or infiltration trenches to enhance the rate of ground water
extraction. One of the two new recovery systems would be installed in Dry Gulch, approximately
3,500 feet southeast of the Inactive Site, and the other would be installed in Filter Gulch southeast of
. the M3 area, approximately 200 feet north of the MMAG propeny boundary. The new recovery .
system in Dry Gulch would probably consist of a trench and well system similar to the existing
Brush Creek system and would recover 5 - 10 gpm. The new system in Filter Gulch would probably
consist of a line of recovery wells similar to the existing Filter Gulch system. Additionally a
treatment step to remove NDMA and UDMH contamination is included. The additional treatment
step associated with this alternative is ultraviolet light (UV) photolysis used in combination with
oxidation to treat NDMA and UDMH.
The ground water would be pumped from the four recovery systems and treated at the
IWTP. Organic and inorganic contaminants would be removed. The IWTP would include air
stripping, carbon adsorption, ion exchange, and the UV photolysis/oxidation process. The treated
effluent would be discharged to the Brush Creek ~G waste water outfall (COPDES Permit
#0001511), located approximately 100 feet downstream of the Brush Creek recovery system.
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GrouBd water monitoring would be conducted to track cont2min:ant migration from the site
and to assess the resulting risks. An alternate water supply would be provided should the need arise
during the implementation of alternative GW-3.
"
Water purchased from the Denver Water Department would be recharged into the alluvium at
Dry Gulch and the M3 area to enhance extraction rates and flushing of the alluvium for more rapid
restoration.
It could, also be necessary to install a small extraction system upgradientof the Inactive Site
recharge system to collect ground water located between the ponds and the recharge system. The
need for such a system would be evaluated during the design phase.
Ground water modeling indicates that ground water restoration time frames required to attain
clean up goals are approximately 4S years for on-site ground water ane! approximately S years for
off-site ground water.
The untreated ground water does not meet the clean up goals at the present time. With the
implementation of alternative GW-3, however, clean up goals would be achieved more rapidly both
off-site and on-site.
6.9
ALTERNATIVE GW-4: CONTINUED OPERATION OF EXISTING RECOVERY
WELL SYSTEMSIINSI'ALLATION OF ADDmONAL RECOVERY WELL SYSTEMS
IN FILTER GULCH AND DRY GULCH UPGRADIENT FROM THE EXISTING
RECOVERY WELL SYSTEMS/ADDmON OF A RECOVERY WELL SYSTEM IN
THE M3 AREAfl'REATMENT BY CHEMICAL REDUCTION, PRECIPITATION,
.CLARIFICATION, AIR STRIPPING, CARBON ADSORPTION, ION EXCHANGE,
AND/OR UV PHOTOLYSISoOXIDATIONIDISCHARGE TO BRUSH CREEK
The objectives of Alternative GW-4 are to preclude contaminant migration off-site and restore
the ground water to beneficial uses by recovering ground water and removing organic and inorganic
contaminants from the ground water. Additionally, this includes systems to collect and treat the
ground water in the Fountain Formation in the vicinity of the Chem Mill and Hydrostat Tank areas.
This alternative provides protection to human health and the environment by removing
cont2minants in the ground water and by reducing contaminant migration off-site.
Alternative GW-4 is a modification of alternative GW-3. It incorporates all the aspects of
GW -4 and in addition includes one more extraction system. The water extracted by the additional
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system would be treated to. remove chromium aDd d1loriDated organic compoUDds. The water would
be recovered from the five systems aDd pumped to the IWTP where organic aDd iDorganic
contaminants would be removed. The IWTP would include air stripping, carbon adsorption, ion
exchange, and the addition of the UV photolysis/oxidation and chemical reduction, precipitation, and
clarification processes. The treated eftluent would be discharged to the Brush Creek MMAG waste
water outfall (COPDES Permit #0001511), located approximately 100 feet downstream of the Brush
Creek recovery system. .
b
Ground water monitoring would be conducted to track contaminant migration from the site
and to assess the resulting risks. An alternate water supply would be provided should the need arise
during the implementation of alternative GW-3.
Ground water modelling indicates that ground water restoration time frames required to attain
clean up goals are approximately 45 years for on-site ground water and in excess of 5 years for off-
site ground water. However, there is some uncertainty associated with the ground water restoration
time. The ground water modeling was conducted using available data on subsurface conditions, and
assumptions were made regarding all the variables. In addition, the model assumes that sources of
contaminAtion are completely removed.
The untreated ground water does DOt meet the clean up goals at the present time. With the
implementation of Alternative GW-4, however, these goals would be achieved on-site and off-site
within reasonable time frames. In addition, an area of high contamination in the M3 area would be
remediated preventing further migration of cOntaminants off-site. .
7.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
7.1
INTRODUCI'lON
In accordance with the NCP, Section 300.430(e), each of the alternatives passing the initial
screening phase of the feasibility study underwent the detailed analysis which specifically addresses
the nine evaluation crit~ria listed below:
Threshold Criteria
1.
2.
Overall protection of human health and the environment
Compliance with aPplicable or relevant aDd appropriate requirements (ARARs)
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September 19, 1990
.Primary Balancin2 Criteria
3.
4.
Long-term effectiveness and permanence
Reduction of toxicity, mobility, or volume through treatment
s.
6.
Short-term effectiveness
7.
Implementability
Cost
Modifyin2 Criteria
8;
9.
State acceptance
Community acceptance
The NCP indicates that a remedy must satisfy the threshold criteria to be eligible for
selection.
7:J,
COMPARATIVE ANALYSIS OF SOn.. ALTERNATIVES
This section provides a comparison of each of the soil alternatives with respect to the nine
.evaluation criteria described above. The results of the comparative analysis are summarized in Table
7-1.
7.2.1 Overall Protection or Human Health and the Environment
All of the alternative, except no action, would provide some degree of protection to human
health and the environment.
Protectiveness is in pan related to the fina1 disposition of contaminants, and alternatives S-4
and S-S employ proven processes to treat all waste and provide for the destruction of organic
compounds with treatment and containment of inorganic contaminants. Both alternatives are
considered permanent remedies and, therefore provide long-term effectiveness and protection.
Alternative S-3 is protective and it includes treatment of all waste, although the organic compounds
would not be removed or destroyed and would potentially be able to leach from the stabilized
product. Alternative S-2 is protective from the standpoint that the potential for direct human contact
is reduced and that infiltration is reduced, thereby reducing the potential for co.ntaminant migration
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TABLE 7-1 SUMMARY OF COMPARATIVE ANALYSIS FOR SOIL ALTERNATIVES
ALTERNATIVE
EVALUATII)N 8-1 8-2 8-3 8-4 8-5
('=-'TFJU(H I
Ovwal Prat8Ctlan at Hu- Not proI8CtIIII. ProIIIdea proI8dIon, buI do8t PnMde8 proIec:tlon. buI un- Highly proIec:t1v8 III1d organic Also highly proIec:tIv8.
1118" Health and the EmIl- not InvoIIIoe IIny trelllmenl or cerI8InIy .xlsts r&g8RIlng contlUllln8nls WOUld be .. 0rg8nIc: contamIn8nts WOUld
"",1II8f1I . Nmovlll of c:orumIn8Ied I0Il 8bl1IV 10 ltablHz. organic: moved and de8Iroyed. Inor- be AIIJIO\/8d and ~.
or waste at In8ctIv8 sn.. conI8IIIInIInts and In turn, glll1lc conl8mln8nls would be Inorg8ntc contamInanls
Potential eJdsIs 'or bUN long-term proIedJon II unc:er- immobilized. would be trnmobItIzed. De-
human .xpoIUr8 possible . lain. gree of organic conI8IIIIn8nI
cap Is not RIIIIntaIned. destruction WOUld be ~
WtIIII less thin A118m1111118
8-4.
Compliance ~ AMRa Not ~8bIe. Compiles WIth .. AAAR8. ComplIes WIIh .. ARAR8. CompIles WIth .. ARARs. Complies WIth .. ARAR8.
l.Dng-lenn l"ectlv8Mu Does not oil. 8ft long-term The ReM cap would pnMde M conI811'11nant8 would be ProvIdes the 1l1OIII elfec:tlw ProIIIdea . highly ell'ec11v8
and pennanence errec:t1v8ness or pennanence. . long-term solution for mini- lrMIed, howewr, the elfec- and perII\IIfIef1I Nmedy. and perII\IIfIef1I Nmedy.
mlzlng the mobUIIy of con- awr.. of organic contemf. Organic conIarnIn8nts wauId 0rg8nIc: c:onIamlnllnll wauId
lamlnan'" ContIllYllnants l18l1I 118bItIzatlon II unc:ettatn. be NIIICMId tom the ... and be NIIICMId tom the ...
WOUld remain In~, un- The ReM cap WOUld decN- destroyed. Inorpntc con- and destroyed. Inorg8nIc
,..ated, and continue to con- 8M lie mobility of c:onI8mI- tamlnants WOUld be Immolll- contaminants WOUld be 1m-
lamlnal. ground WIlIer. nants. Molt organic contemf. Ized. PiIrdIed WIlt. WOUld mobUIzed. PiIrdIed WIler
Molt organic contllmlnatlon IIIItIon In the Dlemlc8l Stor- be perINIrIentty NIIICMId and would be~..
would be permanenlly .. . Tn.... WOUld be treated. The ReM cap moved and treated. The
moved from the QlemIc8l pennallenlly removed. Iorg- would IM1Im1ze the mobility RCRA cap WOUld mInInIIze
Storage Tanle 8f88. Ground 8I1Ic and organic conlemf. of residual corftmInanta. the mobItIIy of conIamInanIa.
water rntondlon would be fIIII1I8 would Nmatn In-fII-
Ins certatn because ,he con- II the Inec:tIv8 sn., buI wauId
lamlnan' IIOIJn:e WOUld not be 1IabIIzed.
be totally conIroI!ed/Nmo- ,
lied.
.
-------
~
TABLE 7-1 (Continued)
AlTERNATIVE
EVALUATION 8-1 8-2 8-3 8-4 8-5 .
CRITERIA
"eduction of Tcndc", 110- None Rem
-------
TABLE 7-1 (Continued)
AlTERNATIVE
.-
EVAlUATION 8-1 8-2 J S... 8-5
CRITERIA .
ImpI8mentablilly T8dnc8IIr Ip8IIIcIng. ImpI8- Implemenlllllon WOUld be 81> IrnpllmerUlIon would be IncInendJon would be 8CCOIn- lmpIemenIetIon of AItemItJve
III8nIIIIIon of !he no 8dIon compllshed U8If!IIINdIly ~ UUIg rw8CIJy IIVIIII- pII8hed UUIg 8IIhIr . wndor $05 WOUld Alqun lie ... of
"emat/v18 would poI8 no 8VIII11IbI8 111818I'taII, con\II8no 8bIe 1111118I'taII, c:onvenIIon8t IUppIIed mobile 1811 or ~ 8IIher . wndor IUppII8d or
proIIIemI. lmplemenlallon of IIonIII equipment, IIIId 1IIbor. ~ 8I1d IIIbor In 18 cated CIfHII. 1811. 0UMr pro. 00-". fabrIcaIecIlhermII .
no 8dIon WOUld be 8CCOIn- implementation WOUld be monthI. The IIdmlnlatnlllv8 C88S8I WOUld be 1m- .1dr8dIon unII. 0UMr pro.
pIIIhed In IIIIIh8n 1 YMF. achieved In 4 monilia. The NqUIr8menIa WOUld be 888Iy plemenled USing re8dlly C88S8I would be 1m-
IIdmlnlsll1lllv8 Alquhm8nt8 8CCOIIIpIIIhed. IMIIIIIbI8 lII8IertaII, CCJrMn- pIemenIed UIIng IMdIy
WOUld be.aIIy ~ UonIII equIpmenI, 8I1d 1IIbor. 8V8II8bIe matertllll, ~
8d. Approxlmlllely 3.5 . 4 YN'8 IIonIII equipment, and 1IIbor.
' WOUld be req'*-d 10 Imple- ApproXIn'lldety 4 yeBrI would
men!. The admlnlltnltlV8 be Alqulnld to IrrIpIemd.
requlremeru WOUld be InOIt The IIdmInIsIraIlv8 req&ft-
complicated to Implement of mentI - relatIVely 88IY 10
an !he dema11ve8. acc:ompIIsh. TIIetm8I 811,
IrIIctIon equipment II ...
8VIIIIIIbI8 Ihan oIh8r ted1nof.
ogIet.
~ Cap'" SO $2,923,000 $21,723,000 $45,923,000 $38,023,000
OIM $38,000 $131.500 $131,500 $131,500 $131,500
....... WartII $800,000 $4,940,000 $23,740,000 $47,840.000 $41.040.000
II8t8 Acc8ptance UnecceptabIe. lMSt ec:c8pIabIe .xcIudIng lM88 accepIabIe .XCludIng AccepCabIe to the Stat., Acceptable to the St8Ie.
$01. $01. depending on the lnc:Iner8tor Stat. concun wtIh 8-5 .
design. l818c:ted remedy.
;
Community Accepl8nc. No commenII receIv8d. ". No comments reCeIved.'" No comments rec:eIv8d. ". No COInI118ID~. ". No c:ornmeru receIv8d. ".
IUIII8d Ull8CC8ptIlble. IUII18d to be acceptable. turned to be acceplllbl8. 8U1'118d 10 be 8CC8p1ab1e. IUII18d 10 be accept8bIe.
,
.,
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September 19, 1990
into the gro~ water. Alternative S-2, however, does not address the existing contaminAted
alluvium which is and will continue to be interSected by ground water and it is not necessarily a
permanent solution. Each of these alternatives also reduce mobility of contAminants remaining in the
soils due to the placement of a RCRA cap over cont~minated or ~eated areas to minimi7-C infiltration
of precipitation.
Alternative S-1 does not provide any protection to human health and the environment. At
present, neither the Inactive Site soils nor the ChemiCal Storage Tank area soils present a threat to
the MMAG employees or trespassers because both areas are covered. The Inactive Site is covered
by soil and the Chemical Storage Tank area by asphalt. However, contAminants in the soil that.
migrate from both areas and enter the ground water could result in exposure to contaminants causing
threats to human health and the environment.
7.2.2 Compliance with ARABs
Chemical-, location-, and action-specific ARARs were identified for the MMAG site and the
alternatives developed. The full ARARs analysis is presented in Appendix A of the feasibility study
(Geraghty &. Miller, 1990b). Each alternative would comply with ARARs. The number of ARARs
that apply to an alternative increases with the amount of treatment involved.
7.2.3 Long-term Effectiveness and Permanence
Alternatives S-4 andS-5 would provide the highest degree .of long-term effectiveness and
would also be the most permanent remedies primarily because both alternatives would use treatment
to remove and destroy organic contaminants at the Inactive Site. Alternative S-4 would use direct
destruction via incineration, whereas Alternative S-5 would use removal via thermal extraction
followed by destruction via incineration off-site. For Alternatives S-3, S-4, and S-5, the inorganic
contaminants would be immobilized by stabilization. The long-term effectiveness of stabilization
would, in part, depend on the ability of the RCRA cap to minimize infiltration through the solidified
mass. RCRA caps bave been used extensively and have been shown to be effective, long-term
solutions for reducing infiltration. The RCRA cap would require periodic maintenance that consi~
of sealing cracks, adjusting for settlement, and revegetating. With proper maintenance and design,
the cap would function effectively and last indefinitely.
Alternative S-3 would be the next most effective and permanent alternative, but because
organic cont~min8.nts remain in place using a technology that has not been proven for organic
RE:012-C08002'-r\iD\rod4S-99
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September 19, 1990
contamift2llts; some questions remain regarding long-term effectiveness. Alternative S-2 would be
the next most effective and permanent alternative. However, CODf2minmon would remain in the
ground untreated and continue to migrate in the environment. Alternative S-1 does not offer any
long-term effectiveness or permanence.
Alternatives S-3, S~, and S-S would enhance ground water restoration because contamination
presently in the saturated alluvium would be treated, and the organic constituents would be removed
as part of Alternatives S~ and S-S. .
Alternatives S-2 through S-S apply in-situ soil vapor extraction at the Chemical Storage Tank
area to remove most of the organic contaminants from the soil, thus providing for long-term
effectiveness and permanence. (Although capping is not planned for this area, a cap to prevent
infiltration would be effective at protecting the environment and preventing human exposure.)
7.2.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternatives S-1 does not involve any treatment of the waste, contaminated backfill.
contaminated alluvium at the Inactive Site. or cont2minated soil at the Chemical ":tarage TanIc area
and therefore does not meet this criterion. .
Alternatives S-2 through S-S all provide some level of reduction in toxicity. mobility. and
volume of contaminants. In all of these alternatives, cont2min:lIIlts in the Chemical storage Tank area
are removed from the soils thereby reducing the toxicity of the soils and eliminating the potential for
further migration of contaminants to the ground water.
This criterion is addressed to the highest degree by alternatives S-3, S~, and S-S because'
these alternatives involve a high level of treatment for contaminants at the Inactive Site area.
Incineration of waste materials in alternatives S-3, S~, and S-S effectively reduces toxicity, mobility,
and volume of contaminants by permanent destruction. Thermal extraction in alternative S-S
accomplishes the same result but by a different mechanism. Volume reduction is a key aspect of S-
S because the thermal extraction process concentrates organic contaminants in a sludge and reduces
the volume of material that must be incinerated. A major difference between S-3, S~ and S-S is the
quantity and type of material which would be thermally treated under each alternative.
The thermal treatment aspect of alternatives S-3, S~ and S-S all result in the generation of
small quantities of residues. These residual waste streams are the result of air "-Hution control
RE:012-co8OO1\muWa\rod4S-99
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September 19, 1990
devices and may be liquid or solid in form. These residues constitute of small volume of wastes
which must be disposed or further treated. Examples of these waste materials are scrubbing liquids
(waste water), spent activated carbon, dry scrubbing residues (salts) and ash.
"
The stabilization treatment portion of alternatives S-3, S~, and S-S will reduce mobility of
CODt~minants in the soils. The effectiveness of stabilization varies with the type of contaminaT1t being
treated. Only inorganic constituents would be treated by stabilization with S~ and S-S. However,
alternative S-3 would utilize stabilization for immobilizing both inorganic and organic constituents.
The use of stabilization to treat organic contaminants is DOt as well accepted as for inorganic
contaminal1ts.
Stabilization treatment would probably result in a volume increase of treated materials due to
the addition of stabilizing or solidifying agents. However, depending on the nature of the material
being treated and the additives used, volume reduction is also a possibility.
In summary, the treatment aspects of S~ and S-S alternatives would provide the highest
reductions in toxicity and mobility. Alternative S-1 provides no reductions and S-2 provides less
reduction in toxicity and mobility than S~ and S-S. . This is because thermal treatment is proposed
for only the discrete waste materials which comprise a small fraction of the contaminated materials at
the Inactive Site.
7.1.5 Short-term En'ectiveness
The short-term effectiveness of Alternative S-l with respect to protecting the environment
would be very low, primarily because contaminants would continue to migrate into the ground water
and significantly increase the time required for ground water restoration. However, there would not
be an immediate threat to human health due to the lack of current exposure to contaminants in the
ground water and at the Inactive Site.
Alternative S-2 would be most effective for the short-term because implementation of the
alternative would talce four months and DO excavation of contaminated soil or waste would be
required. Therefore, risk from iDhalation of vapors, inadvertent ingestion of soil, and dermal contact
associated with the Inactive Site would be insignificant. The cap would immediately stop infiltration
of precipitative and reduce contaminant migration' to the ground water and slow subsequent off-site
migration.
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September 19, 1990
Alteinative S-3 would be a somewhat less alternative for the short-term. Alternative S-5
would follow Alternative S-3 and Alternative S-4 would be the least effective alternative in the short-
term with respect to protecting the environment. All three al~ves have similar components with
corresponding short term risks. The risks associated with dewatering and in-situ soil vapor
extraction would be the same as described for Alternative S-2. In addition, because excavation of
contaminated waste, backfill, and alluvium would be required, there are short term risks associated
with inhalation of, ingestion of, and dermal contact with contaminants for on-site workers. These
risks can be controlled by the use of safe working practices and engineering controls during
implementation.
Oft'-site incineration of the waste (Alternatives S-3 and S-5 only) would pose some risk to the
community as a result of the transport of hazardous waste on public roads and highways. The
loading and unloading procedure may expose workers to contaminants. These risks would be
controlled by establishing procedures for safe transfer of waste materials and careful planning of
transportation. In the event of an accident, waste material would be cleaned up in a relatively short
time (several hours) and community exposure is unlikely.
The transport of treated waste residuals would be required for Alternative S-4 and S-5.
However, the risks would be significantly less with S-4 because the materials being transported
would be free of organic contaminants.
During S-3 stabilization treatment would result in a risk to workers from inhalation of
. vapors. Inadvertent ingestion or dermal contact with soil is a risk for all three alternatives S-3, S-4,
and S-5. This risk would be greater for Alternative S-3 because organic contaminants would still be
present during stabilization.
In summary, the short term effectiveness of alternative S-2 is the greatest because it provides
a relatively quick solution for remediation and the human health risks associated with implementing
the remedy are less than S-3, S4 and S-S. Alternative S-l provides DO .short term protection to the
environment, however, S-1 poses DO threat to human health associated with implementation.
7.2.6 ImplementabiUty
Implementability refers to the technical and administrative feasibility of implementing an
alternative and the availability of service and material. All the alternatives would be technically
implementable. Conventional construction equipment would be used for excavation, transport, and
RE:012-co1OO2\mar1i11\rod4S-99
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September 19, 1990
>.
replacement.. On-site treatment processes would be vendor supplied or designed and fabricated by
MMAG. .Off-site incineration and disposal would be performed at permitted facilities. All the
technologies involved in the alternatives are reliable. Incineration and stabilization have been used
extensively to treat hazardous waste and are considered the BDA Ts for organic and inorganic
contaminants, respectively. Thermal extraction is a relatively innovative technology that operates on
proven thermodynamic properties. A RCRA cap is considered the best demonstrated available
technology (BDAT) for cover types and has been used extensively and successfully at hazardous
waste sites and landfills. In-situ soil vapor extraction is a relatively new technology adapted from the
proven air stripping technology for removing VOCs from aqueous streams. Carbon adsorption is
proven technology widely used in waste water and water treatment plants as well as hazardous waste
sites for removing organic contaminants from aqueous waste streams.
Alternative S-S has the disadvantage of utilizing a thermal treatment technology that is not as
readily available as conventional incineration. Thermal extraction is relatively new technology and
although there are several companies offering the technology, they are fewer in number than
incineration vendors.
The administrative feasibility of alternatives varies from alternative to alternative. Alternative
S-2 could be implemented with little administrative or technical difficulty. The only administrative
requirements to be achieved would be to meet ambient air quality standards for the in-situ vapor
extraction process. Alternative S-2 would be readily adaptable if additional remedial actions were
necessary at a later date. Alternatives S-3 and S-S would be relatively simple to implement from a
regulatory stand point. The regulatory requirements for on-site treatment are easily implementable.
The off-site treatment and disposal requires very little administrative efforts because the materials
would be treated at permitted hazardous waste TSD facilities.
Alternative S-4 would meet with the most difficult alternative to implement on-site due to the
regulatory requirements for incineration, such as trial burns.
7.2..7 Cost
MMAG estimated capital, O&M, and present worth costs for each alternative. Tbe costs are
presented below:
RE:Ol1-c0B002\martin\rocl4S-99
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September 19, 1990
. . Alternative C~pital ~ Present Worth
S-1 $0 $39,000 $ 600,000
S-2 $ 2,923,000 $131,500 $ 4,940,000
S-3 $21,723,000 $131,500 $23,740,000
S-4 $45,923,000 $131,500 $47,940,000
S-5 $39,023,000 $131,500 $40,040,000
MMAG also conducted a cost sensitivity analysis to evaluate how the costs respond to
fluctuations in various factors such as volumes, interest rates, and unit costs. The results of the
sensitivity analysis are summarized below.
SENSITIVITY ANALYSIS OF PRESENT WORTH COSTS.
Alternative Low Cost Hi2h Cost
S-1 . $ 260,000 $ 980,000
S-2 .$ 2,950,000 $ 7,180,000
S-3 $10,150,000 $ 40,380,000
S-4 $16,650,000 $107,480,000
S-5 $17,150,000 $ 69,080,000
As indicated in the table above, significant uncertainty exists regarding the cost of Alternative
S-4. The low end cost is 35 percent of the estimated present worth cost and the high end cost is 224
percent more than the estimated present worth cost. The uncertainty associated with costs for the
other alternatives is not as great.
7.2.8 State Acceptance
The no action alternative is not acceptable to the State of Colorado (CDH). CDH prefers
alternatives requiring treatment over alternative S-2 and bas indicated concurrence with EP A on the
selected remedy.
1tE:012~\mutiD\rod45-99
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September 19, 1990
7.1.9. Community Acceptance
Community acceptance of the soU alternatives is assumed to be in concurrence with the State
and EP A. No significant comment regarding the soU alternativeS was received during the public
meeting or during comment period on the propos~ plan.
7.3
COMPARATIVE ANALYSIS OF GROUND WATER ALTERNATIVES
This section provides a comparison of each of the ground water alternatives with respect to
the nine evaluation criteria described in Section 7.1. The results of the comparative analysis are
summarized in Table 7-2.
7.3.1 Overall Protection or Human Health and the Environment
Each alternative except DO action provides some protection of human health and the
environment. The ground water alternatives were developed and evaluated based on the assumption
that the two major source areas of contamination would be removed. These sources are the
cont.amin9nts at the Inactive Site and Chemical Storage Tank areas.
Alternative GW -1 would be a step backwards if it were to be implemented. The existing
recovery well systems would be shut down and contamination would migrate unrestricted off-site.
The long-term impacts would be considerabl~ as the contaminated ground water would contaminate
clean ground water and water users distant from the site could be affected. Alternative GW -1 is not
protective of either human health or the environment.
MMAG is presently implementing Alternative GW-2. MMAG has been able to demonstrate
that this recovery well systems is effective at collecting and treating alluvial ground water. The
recovery well systems used to extract ground water are conventional and proven. The treattnent
processes used are also conventional and widely used to treat municipal water supplies. (The current
treattnent process for ground water includes only air stripping.)
Alternative GW-3 is protective for the same reasons as GW-2 and is possibly more protective
because it reduces the restoration time frame and. provides for the treatment of two important
contaminants, NDMA and UDMH.
RE:Ol1~\maniD\rod4S.99
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TABLE 7-2. SUMMARY OF COMPARATIVE ANALYSIS FOR GROUND WATER ALTERNATIVES
ALTERNATIVES
.
EVALUATION
CRITERIA GW.1 GW-2 GW-3 GW-4
Ownn 'raI8cIIon of Don noI pnMde 8nV protection 10 The ~ II protedM. "'-nIIv The ~ II protectlv8. Men JIfO' The remedy II proIectlv8. MOIl
HUmin HMllh and Ih8 hum8n M8IIh and Ih8 If1IIIronm8nl being Implemented ~ MMAG. Ha IedIv8 10 hUmIn heanh and II1e envl- proIedM aIIemat1v8 becauM .
EnvIranmenl been Ihown 10 en8Cllv8ly predude IOIIment than GW.2 becaI8e . WOUld IpICIIcaIy addressn IIIcnawn
on.llle mlgndlon 01 ground water In lllCOIpOr8Ie an addnonal recovery MIl ground WIler contamination. In
the a/1IMum. ly8Iem and UV phoIotysI8/oxIdaIIon llddlllon 10 c:oIItdJng and IrNIIng
10 capture and tre.. NDMA and NDMA/UDMH conlamlnalJon, cillo-
UDMH contamination, respedIveIy. mlum contamination In II1e M3 8M
' WOUld be coIIIcIed and IrMItd !IV
d1em1cal redUdlon/prec:IphIIon!
clarlllcaJlon.
Compll8M8 with AIWt. NoI 8ppI1c8IIIt. Complltl WIll II NWI8 8nd meets Compllel WIth .. NWI8 8nd WOUld Compllel WIth II NWI8 8nd would
MMAG'I COPDES peftntI require- me.. MMAG'I COPDES pennI req- meet MMAG'. COPDES pII1III...
menta. Ulrementa. qulremenII.
Long-term Ett8C11v8- '. NIIIunII 8ll1I1UII1on pI'OCII8II would Rem8dlaJIon goeI8 WOUld be 8ChI8v8cI RImedIallon goa/I woutd be 8CtI1ewc:I RemedIation goa/I WOUld lit
.nd P8nn1..- occur and ground WIlIer remediation In 130 para for on-IIIe ground water In 45 para for on-llte ground WIlIer 8ChI8wd In 45 yeara for OIHIIe
goeII would be 8It8Jntd If IOme poInI and In exC881 Of 5 pan for on-..e and more lhan 5 year8 for oft-lfte ground WIler and more Ih8n 5 yt8rI
In the future (nIImated to lake In ground WIlIer, There would be no ground water. Removal and Ire..m- for on....e ground WIler. ReIncMII
exC88I 01130 YMB). ~ thai point, IIgnIllcanl rtIkI 8I8OCIaItd WIth long- tnI 01 contaminated ground WIlIer 8nd lrealment of contllll'lln8ted
b8nIng MY LIIIcnown IOUr'Ce8, AIIer- lerm expoeure IInce contamInanI would lit eftectlv8 and permanenI ground WIler WOUld lit efted1v8 8nd
n8Iv8 QW.1 WOUld be conIIdered IeIIeI8 woutd meet remtdlallon go8JL WIth IOUfeII relllCMld. There woutd pemIIIIl8I1I WIth IOUR:8I ~
~ 8nd etredIYIln II1e long- lit no IIgnllk:8nt rtIk 8IIOcIaIed WIth There woutd lit no ~ rIIk
Ierm. long-term expolUrlllnce conI8mIn8nI lIISOc:IaIed WIll long-term IICJ1C*1r8
llvell WOUld meet remedlllaon goa/I. llnee contamlnanlllwll would meet
remedlallon goa/I.
Reduction of Tcndc:.." Mo- Don noIlrMIIw 8nV h81ment and Nil IIrlpplng WOUld eftldlwly 1'11110¥8 Nil IIItppIng would enldlwly r8nICM Nilllrtpplng WOUld eftldlwly ...
bltlly, or Volume Through ~ WOUld not pI'O\/Ide anv ... 99 percent 0I1I1e VOCI. C8rbon 99 percent 0I1I1e VOCI. C8rbon IIICM 99 pen:enI 0I1I1e VOCI. Cer.
Tre.lmlnI cludlonalo Ioxlc:lly. mobIllIV. or voI- 8dsorpI1on would eftectlv8ly relllCM edsorpllon would eftectlv8ly retnOIIe bon 8dsorpI1on would effectively
ume. up 10 99.99 pen:enl of II1e rematnlng up 10 99.99 percent of the remaining r8nICM up 10 99.99 percent 0I1I1e
organic c:onIamInanI.. Ion exc:hange orgahIc conIamInanIs. Ion exchange remaining organic contamInanIL
would enectlvely relllCM In excelS of would eftectlv8ly retnOIIe In exceu of Ion exchange would enedlll8ly ...
99 pen:enl 0I1I1e inorganic oontaml- 89 percent 0I1I1e inorganic contaml- IIICM In excell 0199 percent 0I1he
. nanls. Remediation goa/IlInd rIIk- nanIs. UV phototysl8/olddallon WOUld inorganic contaminant.. UV ~
based c:onc:entllltlon IeveI8 would lit enldlwly ",move and destroy In ys/I/Olddallon would elfedlv8ly ...
met. Salls,," SARA prelerence for excess 01 89 percent 0I1I1e NDMA IIICM and deslroy In excell 01 98
trea/menl. and UDMH contamlnallon. Remedla- percent 0I1I1e NDMA and UDMH
lion goall and rIsk-based c:onc:entra- contamination. Chemical r8dUdIon
lion k!. "Is would be met. Satisfies would enectlv8ly remove In exceu
the SARA preference lor lrealment of 99 percent of lhe chromium cont-
amination. Satlsftes!he SARA pref-
erence lor I",a/ment
-------
TABLE 7-2 (Continued)
ALTERNATIVES
EVALUATION GW-1 GW-2 GW-3 GW-4
CRITERIA '
lhOrt-term Eff8ctIv8I- 1be lllvlrolon18l1l II noI protected. Alt8r111111v8 GW.2 MIUId noI be 8II8C- M8m1111v8 GW.3 MIUId noI be eIIec- M8IT1IIII\I8 GW-4 MIUId noI be e118C>
1tI8n MIUId noI be II1Y emIssIonIlo 1M In Ih8 1IIort.c.rm. ttIM8IIer. ~ 1M In the lhoft-lenn.. EmIIronrn8nI8I 1M In the 1IIort-tenn. EfI\/Ironm8nIaI
Ih8 ... and c:onMqU8I1Ily no Ixpoltn Ie hMlth end the 8f1IIIronmenl .. d8gl'lldatlon woutd be mtnmtzeel CItr- d8gnIdatton woutd be mtntmIHd 011-
to hurn8n8 t/voUgtI D. protecteel CUtngImptern8rUUon. "I. However. public health and the "I. HcM8wr, pubic h8aIh and the
envtronrn8nt IIr8 prot8d1d during 8f1VIronm8nt .. protected during
tmpI8m8nIatlon. tmpI8m8r\I8tlon.
lmpl8m8nlabillty E8IIIy 1mpI8m8nt8d. Woutd requn Alt8llllll1Ve GW.2 II ~ In opera- Alternetlw GW-3 MIUId b81mptem8nt- AltemllllVe GW-4 woutd be .....
, cI8cornIIItontn IJdstIng r.c:owery wd tton and, th8refcn, has the highest ed wIIh II1II8 dIIttcuIty. conventional menleel wtth ..... dllllcutty.
1y8t..... Woutd be tmpIem8nted In r81ng wIIh r88p8d to Imptementllbl- ~ woutd be IJI8d to const- CorMntIonlll equIpm8nt woutd be
.... than - yeIII'. Illy. IUd the addllonal f8OOV8fY IyItem U88d to CXIOStJUCt the 8ddI1onIII
and the W phoIotyIIII/oJddatIon IyI- -v ly8tems end the W plio-
18m woutd be obtained fIom . vendor totyllll/OJddetIon ly8tem wautcI be
and Implemented as pmt of MMAG'I obtllln8d frum . vendor end .....
Ixlltlng IWTP. ConstructIon of the menleel .. pmt of MMAG'I IxIItIng
addllonat recovery welt aystem and IWTP. 1be chromium ...atment
the NDMA/UDMH treetment procell proces8 II already In ~ .. MMAG
woutd take Ie88 than - yeIII'. '01' UM wIIh 1I181r IndusIrtaI WaIII
Itr1IIII1. ConItIUdton of Ih8 addl-
tional -v W8IIly8tems and the
NDMA/UDMH treatment proc:III
woutd take .... than - Y'I8'.
Coat Cap1t81 $0 $0 '1,100,000 '1.300,000
0'" 8180,000 8514,000 '1,100,000 , '1,100,000
Pr8I8nt WorIh 82,800,000 87,800,000 '18,000,000 '18,200,000
lta18 Acc8ptance ~1IbI8. Acc8pt8bt8 to the Stall. ~ to the Stall. Acc8ptabll to the Stall. StI8I con-
CUf8 with GW-4 .. the l118ded .......
Iftt.
Community Accept8nc:e No COIIIITI8IIta 18C11ved. Assumed No c:omments ~ No comments r8C81ved. Assumed No convnenI8 r8C81ved. Auum8d
unacceplabll. acceptabtl. ac:cept8bI8.
,
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September 19, 1990
. Alternative GW -4 i,ain is protective and reduces uncertainty associated with Alternative
GW-3 by including an additional recovery well system in the M3 area to collect a chromium plume
that originates in the M3 area. In addition, a chemical reduction/precipitation/clarification process
would be used to remove the chromium and any other metals as well as other inorganic contaminants
from the ground water. Alternative GW -4 does not result in any reduction to the ground water
restoration time frame when compared to alternative GW-3, but it does address a known
cont2min~ed plume. .
7.3.2 CompUance with ARABs
Chemical-, location-, and action-specific ARARs were identified for the MMAG site and
ground water alternatives developed. The full ARARs analysis is presented in Appendix A of the
feasibility study (Geraghty & Miller, 1990b).
-
Alternative GW-l may attain, in 200 years, the chemical-specific ARARs. Alternatives GW-
2, GW-3, and GW-4 would comply with all ARARs. Since Alternatives GW-2, GW-3, and GW-4
would all collect and treat for detectable contaminants, each would equally comply with ARAR.
7.3.3 Long-term Effectiveness and Permanence
Long-term effectiveness and permanence are the measure of how long into the future the
remedy will last and how protective it is during that time. Considering that the ground water would
eventually be restored (by natural attenuation'in the case of GW-l or b>: active treatment in the case
of Alternatives GW-2, GW-3, and GW-4), all the alternatives would provide adequate long-term
effectiveness and all would be permanent assuming that there are no unknown sources that would
prevent restoration. However, alternatives GW-2, GW-3 and GW-4 assure long term effectiveness
. by using active treatment.
7.3.4 R~udion of Toxicity, Mobility, or Volume Through Treatment
Alternative GW-l does DOt involve treatment of contamift2nts. However, the natural
attenuation processes that occur would reduce the toxicity and volume of contaminated ground water.
Alternatives GW-2, GW-3, and GW-4 woUld effectively use the recovery well systems to
reduce the mobility of cont2minants. Alternative GW-4 would provide the greatest reduction in
CODt2min3nt mobility for the short:erm followed by GW-3 then by GW-2, predominantly because of
RE:011~\martia\rocl4S-99
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September 19, 1990
the number of reaJvery sYstems employed. Residuals such as sludge from treatment processes would
be treated and disposed of off-site to ensure meeting this criteria for each alternative.
Alternatives GW-2, GW~3, and GW-4 would also reduce ,the toxicity of conwninants through
treatment that removes CODt:aminants from the ground water. Alternative GW-4 would achieve the
highest reductions, followed by GW-3 and GW-2 primarily because it addresses all cont:amin:ants of
concern including chromium and NDMA and UDMH.
'->
7.3.5 Short-term Effectiveness
None of the alternatives will reduce the threat in the short-term because it may require 45
years or more to attain remediation goals. However, GW-2, GW-3, and GW-4 are protective
because ground water is not currently used for human consumption and an alternative water supply
will be provided during implementation of the remedy should the need arise.
The ground water treatment process, air stripping, releases low levels of volatile organic
chemicals into the air. However, the release will be subject to air pollution controls which will
protect human health and the environment.
Environmental degradation would be reduced by Alternatives GW-2, GW-3, or GW-4.
. GW-4 would be most beneficial to reducing environmental degradation in the short-term followed by
GW-3.
7.3.6 Implementability
Alternative GW-2 ranks the highest with respect to implementability, because it is already in
operation. Alternative GW-I would be easily implemented by shut down of present operation.
Implementation of Alternatives GW-3 and GW-4 would require installation of wells or
trenches, constrUction of small diameter pipelines, and process modifications to MMAG's IWTP.
This makes GW-3 and GW-4 the most technically difficult to implement.
RE:012-c08002\manin\rod4S.99
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September 19, 1990
7.3.7 Cost"
MMAG estimated capital, operation and maintenance (O&M), and present worth costs for
each alternative. The costs are presented below:
Annual
Alternative C~pital QsW Present Worth
GW-l $0 $180,000 $2,800,000
GW-2 $0 $514,000 $7,900,000
GW-3 $1,100,000 $1,100,000 $18,000,000
GW-4 $1,300,000 $1,100,000 $18,200,000 .
MMAG also conducted a cost sensitivity analysis to evaluate h~w the costs respond to
fluctuations in various factors such as volumes, interest rates, and unit costs. The results of the
sensitivity analysis are summarized below.
SENSITIVITY ANALYSIS OF PRESENT WORTH COSTS
Alternative Low Cost Hi~h Cost
GW-l $1,400,000. $4,300,000
GW-2 $3,400,000 $13,100,000
GW-3 $7 ,500,000 $30,600,000
GW-4 $7,700,000 $32,800,000
The sensitivity analysis indiCates that approximately the same level of uncertainty exists for
each alternative. This is reasonable since Alternatives GW-2, GW-3, and GW-4 all employ similar
processes and operate under similar conditioDS.
7.3.8 State Acceptance
. .
1be no action alternative is not acceptable to the State of Colorado (CDH). CDH supports
EPAs selection of Alternative GW-4 for ground water remediation.
RE:OI2~002\maftiD\rod4.s-99
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September 19, 1990
. 7.3.9 ColDIIJunity Acceptance
Community acceptance of the ground water alternatives is assumed to be in concurrence with
the State and EPA. No significant comment regarding the ground. water alternatives was received
during the public comment period on the proposed plan.
'-.>
8.0 SELECTED REMEDY
Q
The selected remedy combines two alternatives: S-S for treatment of contaminated soil and
waste from the Inactive Site Ponds and the soil in Chemical Storage Tank area, and GW 4 for
cont~inated ground water treatment.
The selected remedy addresses the remedial action objectives by including remediation of the
principal threat at the site, the Inactive Site area, which contains highly concentrated and mobile
contaminants and the soil in the Chemical Storage Tank area. Remediation of ground water is also
part of this remedy. As a result of these actions, surface water on-site is expected to be remediated
also:
Both EP A and CDH have evaluated the alternatives and agree that this remedy will provide
the most effective measures to ensure long term protection of human health and the environment
satisfying requirements under CERCLA and attain the ARARs from other Federal and State
regulations. In particular, the remedy is consistent with anticipated elements of RCRA corrective
action as well as closure standards for RCRA hazardous waste units. These considerations are
particularly important because it is anticipated that the remedy will be implemented under the RCRA
corrective action authority.
The remedy does not specifically address contamination which originates from Air Force
(PlKS) property. However, because ground water in Brush Creek and Dry Gulch will be
intercepted, contaminaflts from Air Force property will be treated also. At this time, contamination
in Lariat Gulch will not be addressed by this remedy, except that monitoring will be conducted. The
U.S. Air Force and EPA are expected to address Lariat Gulch as part of the Interagency Agreement
for that site.
RE:012-c08002\martin\rocl4S-99
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September 19, 1990
8.1
DESCRIPI'ION
8.1.1 Alternative 8-5: Dewater/Orr-site Incineration and Disposal of Wastefl'hennal
Extraction of Backfill and AlluviumlEx-situ Stabilization of Backfill and
AlluviumlRCRA CaplIn-situ Soil Vapor Extraction -
. Specifically, the objectives of this portion of the selected remedy are to mitigate the impact
that the Inactive Site Pond area contamination is having on ground water and to reduce the potential
for further migration of chlorinated organic chemicals from the Chemical Storage Tank area. The
remedy is designed to address both the immediate need to control the source of contamination to
another media (ground water) and prevent the potential for future exposure of humans to
contaminants at both areas. In order to provide a permanent solution, organic contaminants will be
removed and inorganic contaminants will be immobilized at the Inactive Site, infiltration of
precipitation through the Inactive Site will be reduced, and organic contaminants from the Chemical
Storage Tank area will be removed.
""
()
Alternative S-S incorporates the following components for the Inactive Site area: dewatering
of the perched water; excavation, off-site incineration, and off-site disposal of the waste in
accordance with LDRs; and excavation, thermal extraction and stabilization of contaminated backfill
and alluvium. The treated backfill and alluvium will be placed back into the excavation, and covered
with a multi-layered cap over the Inactive Site area. In-situ soil vapor extraction will be used to
. remove VOCs at the Chemical Storage Tank area. In addition, this alternative includes the off-site
incineration and disposal of the residual organic laden sludge from the thermal extraction process and
the off-site incineration and disposal or regeneration of the carbon 'from the in-situ soil vapor
extraction process and the thermal extraction air treatment system. This pOrtion of the remedy will
be implemented within approximately 4 years. Figure 8-1 depiects the selected remedy for the
Inactive Site.
Approximately 1.3 million gallons of perched water will be extracted and treated along with
. the contalnjpated ground water. The waste material, approximately 2,100 cy, will be excavated, and
transported, and incinerated off-site. The proposed facility is Rollins in Deerpark, Texas. However,
any off-site facility used as part of this remedy must satisfy the requ&rement in section 121(d)(3) of
CERCLA.
RE:012.co1OO2\maIWl\rod4S-99
,85
-------
"DEWA'mUNQ
DCAVA'I10N
u
~
{J,
o MAnJUAL SECUGA'I10N
r::1 .. ~ "
...0........ ~ " --
",.& .~
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............ ~ 0"'''''''''
.. ~........... ~ ..,..........
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Sl'ABIIJZA'I10N/SOlJDmCA'I10N
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8Aa INTO EXCAVATION
OIl,... , tv""
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....... hdIItF
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~o
ac:aA CAP
FIGURE 8-1. MARTIN MARIE'ITA AsTRONAUTICS GROUP
SELECTED REMEDY FOR THE INACI'IVE SITE
-------
September 19, 1990
. The contAminAted backfill aDd alluvium would be excavated doWD to action levels, UDdergo
thermal extraction to remove organic contamin2nts, aud be stabilized to immobilize iDorganic
conVlmin2nts. The organic contaminAnts in the Chemical Storage Tank area would be permanently
removed.
A series of wellpoints will be installed in the perched zones of the Inactive Site to extract
water. The water will be temporarily stored in holding tanks and either trucked, pumped, or gravity
fed to the IWTP to be treated by the processes discussed in GW-4. The treated water would be
discharged in accordance with MMAG's COPDES permit. The dewatering process would take
approximately 2 to 3 months to complete.
Excavation of the waste, contaminated backfill, and contaminated alluvium at the Inactive
Site will be necessary in order to treat the materials. (No excavation will be required at the
Chemical Storage Tank area.) Excavation would be achieved utilizing conventional construction
equipment such as backhoes and front-end loaders. Controls for VOC emissions during excavation
actiyities will be evaluated during the design phase.
Material segregation by .conventional mechanic equipment will be necessary at the Inactive
Site. It is anticipated that three stockpile or staging areas will be necessary: one for the
uncontaminAted cover material, one for the waste, and one for the contaminAted backfill and
alluvium. The waste material will be loaded onto plastic-lined trucks and transported off-site to an
incinerator and landfill. The backfill and alluvium will then be treated by thermal extraction and
stabilization. The cover material will be placed back into the excavation once the excavation and
treatment processes are complete. (Cover material i~ that soil which is uncontaminated or contains
constituents below the action levels specified in Table 8-1.) Materials will be stockpiled only to the
extent that the site remediation is run in an efficient, cost effective manner.
The waste in the Inactive Site ponds is considered a RCRA Listed Hazardous Waste. The
waste, approximately 2,100 cy, will be loaded onto lined trucks and transported to an off-site
incinerator permitted to accept FOOl, FooS, and F019 listed wastes. The waste will be treated to
comply with the FOOl and FOOS LDR treatment standards. If incineration is used and residues do
not satisfy the LDR treatment standards for FOl9 (inorganic) wastes, they will be stabilized prior to
land disposal in a RCRA Landfill. These activities will be consistent with Section 121(d)(3) of
CERCLA.
RE:012-a>8902'-"iD\rocI45-99
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'"
September 19, 1990
TABLE 8-1
MARTIN MARIE'lTA ASTRONAUI'lCS GROUP SITE
SOIL ACTION LEVELS AND TREATMENT STANDARDS
ORGANIC
CONTAMINANTS TREATMENT
OF CONCERN ACTION LEVELS STANDARDS
VOLATILE ORGANIC COMPOUNDS TCLP, mgll(!) TCLP, mgllm
Acetone 0.59 160
1,l-Dichloroethene 7.2
trans 1,2-DiChloroethene 33
Tetrachloroethylene 0.7 0.05
Toluene 0.33
1,1,1- Trichloroethane 0.41
Trichloroethene 0.5 0.091
Xylenes (total) 28
SEMI-VOLATILE ORGANIC COMPOUNDS Total Cone, mglkg 0)
Anthracene 4.0
Benzo(a)anthraeene 8.2
Benzo(a)pyrene 8.2
Benzo(gbi)perylene I.S
Benzo(b+ k)t1uoranthenes 3.4
Bis(2-ethylhexyl)pathlate 28
Chrysene 8.2
Di-n-butylphthalate 28
Fluoranthene 3.1
lndeno(I,2,3~)pyrene 8.2
Phenanthrene 3.1
Pyrene 8.2
1,2,4- Trichlorobenzene
Phenol
PCB - 1242 25.0 1.0
PCB - 1248 25.0 1.0
PCB - 1254 25.0 1.0
PCB - 1260 25.0 1.0
8S
RE:OI2~\ManiD\Jlod1bI.8-1\ak:
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September 12, 1990
TABLE 8-1 (continued)
MARTIN MARlE'ITA ASl'RONAUTlCS GROUP SITE
SOIL ACTION LEVELS AND TREATMENT STANDARDS
ORGANIC
CONTAMINANTS TREATMENT
OF CONCERN ACTION LEVELS STANDARDS
INORGANIC COMPOUNDS TOTAL CONC, mglkg(4) TCLP, mg/l(%)
Acetone 0.59
Aluminum 116000
Antimony
Barium 100
Beryllium 1.56
Cadmium 3.2 1
Chromium (Total) 60 5
Copper 4343
Lead 31 5
Mercury 3.7 0.2
Nickel
Silver 5 5
Fluoride 2S
Nitrate + Nitrate
Cyanide (total) 590 mglkgCSl
Cyanide (amenable) 30 mglkgCSl
NOTE:
LDR treatment standards are.not ARARs for contaminated soil and debris. However, the
treatment standards are being used as target cleanup levels. Treatability variances for soil
and debris are available. .SS Federal Re2ister. 8760 (March 8, 1990).
1. Regulatory levels for toxicity characteristic constituents as published at 55 Federal Rel!ister,
(March 29, 1990).
2. Treatment standards published in the at the S5 Federal Rel!ister, (June 1, 1990).
3. Treatment standards published at SS Federal Re2ister. (June 1, 1990)
4. Background levels from the remedial investigation report (Geraghty &. Miller, 199Oa)
5. Treatment standards for F019 wastes as published, at SS Federal Rel!ister, (June 1, 1990).
89
.,RE:012-c0&002\Mania\RodabI.B-l \ale:
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September 19, 1990
On':'site, appro~imAtely 24,400 cy of contAmintltM backfill and alluvium will be treated by
thermal extraction to remove volatile and semivolatile organic contAminAnts. Thermal extraction is a
low temperature thermal treatment process which volatilizes organic contAminAnts from the soil
matrix. Operating temperatures are low. preventing combustion of the organic contAminAnts and
oxidation of the inorganic contAminAnts. The process produces an organic-free soil and an off-gas
that, when treated, generates waste water, clean air, and an organically contAminAted sludge.
A typical' thermal extraction system would consist of an extraction vessel and gas. treatment
syst~m. Material to be thermally treated would be screened andlor undergo size reduction to remove
large particles. Several types of thermal extraction processes are available. Selection of the
equipment will be performed during the design phase. The off gas treatment system removes
contaminants from the gas stream usually with a condenser and particulate collection equipment.
Thermal extraction differs from incineration in several ways. One of the major differences is
that thermal extraction is not a combustion process and, therefore, does- not have stringent permit
requirements. The thermal extraction process operates at significantly lower temperatures compared
to incineration. Thermal extraction is accomplished at 300-600°F while incineration requires a
minimum temperature of 1,200°F. Thermal extraction contributes less to thermal pollution then
incineration because gas exiting the stack is usually within 10°F of ambient air temperatures.
Thermal extraction is best suited for low level organic contAmin2tijon whereas incineration is best for
high organic materials with significant heat value.
One of the major differences between thermal extraction and incineration is that thermal
extraction is a removal technology and incineration is a destruction technology. As a result, the
organic-laden sludge residue generated from thermal extraction, which is on the order of 0.5 to 10
percent of the feed volume, requires additional treatment via incineration to achieve destruction to
levels acceptable for land disposal. Incineration is more efficient than thermal extraction at removing
org~c contAminAnts. Incineration has a destruction and removal efficiency (DRE) of 99.99 percent
compared to a removal efficiency for thermal eXtraction of up to 99 percent. Mobile or transportable
units are available for both technologies.
Following thermal treatment, approximately 24,400 cy of backfill and alluvium would be
treated by ex-situ stabilization. The stabilization process incorporates the contaminated soil into a
matrix additives such as Portland cement, water, and proprietary compounds to immobilize the
contaminants by chemically and physically binding them in-place.
RE:012~\martiA\rod45-99
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September 19, 1990
. Stabilization processes employ ion exchange, nucleation, chemical bonding, and other
chemical reactions to treat CODbminated materials. Removing the organic contamin,11U by thermal
extraction will increase the effectiveness of stabilization.
Stabilization can be performed in an open pit, in concrete trucks, and in fabricated systems
designed specifically for stabilization. Both stationary and mobile systems, are available. The
backfill and alluvium would be mixed with additives in a manner to be determined during the design
phase. The mixed product will be placed back into the excavation and capped.
The remediation goal for treatment of the CODtaminJited soil is to meet LDR treatment
standards for the waste types identified above. If pilot scale treatability studies demonstrate that
treatment levels specified by LDR standards cannot be achieved, a treatment'level based upon soil
and debris variances will be established. The combination of removing organic contamination and
immobilizing inorganic contamination will protect ground water from ~ntaminant leaching and
reduce the potential for direct contact with contaminated soil.
A multi-layered, engineered cap will be installed to cover any area where treated soil is
returned to the Inactive Site. The cap will be consistent with RCRA capping design standards for
land disposal units.
A RCRA cap is proposed for covering the Inactive Site area, following replacement of
treated materials. This may include the five ponds and the area adjacent to the ponds as depicted in
Figure 8-2. The extent of capping will be determined during the design phase. A RCRA cap was
selected because it is the best demonstrated available technology. It provides a high degree of
effectiveness at a reasonable cost and is easily maintained.
The RCRA cap would consist of an upper vegetated layer underlain by a drainage layer over
a low permeability layer as shown in Figure 8-2. The low penn:ability layer can be composed of
natural soU, admixed soU, a synthetic liner, or any combination of these materials. A synthetic liner
would overlay the low permeability ~raI soil or soil admix. The synthetic liner allows minimaI
liquid penetration for a minimum of 20 years as long as it is properly installed and maintained in
accordance with the manufacturer's instructions. The low pecmeabiJity soil layer provides additional
protection in the event the synthetic liner fails.
Relative to other capping options, the RCRA cap requires little maintenance. Since most of
, .
the cap is composed of natura1 materials, erosion and settlement are the major concerns. Both
RE:Ol2-C08Q02\mutia\rocl4S-99
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Treated Soli
Cov.r Material
.'
~ Return to Excavation
~
a
Q
:.
..
.,.\.
" .
{).
RCAA Cap (see
Detail on Right)
RC~ Cap
.~
~
FIGURE 8.2 . MARTIN MARIEITA ASTRONAUTICS GROUP
RCM CAPPING PROCESS
-------
September 19, 1990
concerns would be minimi7i,d by establishing and maintaining a healthy vegetative cover. The cap
would be inspected regularly for the design life of the cap.
Ground water monitoring will be conducted around the Inactive Site to monitor potential
CODtaminant migration from the area. Soil samples will be collected from the Chemical Storage
Tank area to evaluate the treatment effectiveness.
The Site will be monitored on a routine basis consistent with RCRA requirement$ to
determine if the remedy is effectively reducing cont2minal'lt levels in the ground water and if the
source control measures effectively preclude contaminant loading on the ground water. Post-closure
monitoring is required and will be performed annually or more frequently.
During the RIIFS process, bench scale treatability tests were performed on Inactive Site
materials to study thermal and stabilization treatment. The analysis of .the treatability test results is
reported in the test report (Geraghty & Miller, 1987b). In general, the test results were supportive
of the selected remedy. The thermal treatment testing demonstrated that both semi-volatile and
volatile organic compounds are removed from pond samples at a treatment temperature of 1022 of
(SSO°C) but not at 220°F (104°C)., The test results report concluded that removal efficiencies of
greater than 99~ were achieved. The stabilization testing results concluded that cement based
treatment will reduce mobility of contaminants and proposed treatment additive ratios. However, the
test results cannot be used for the purpose of remedial design.
Additional treatability testing of thermal vapor extraction and stabilization/solidification must
be performed to support the design phase activities. This treatability testing will be used to verify
the effectiveness of the treatment processes and establish operating parameters for design of full scale
equipment.
In-situ soil vapor extraction would be used to remove TCE and 1,1,1,-TCA from the
Chemical Storage Tank area subsurface soil. The in-situ soil vapor extraction process is depicted in
Figure 8-3. A series of extraction wells connected to a vacuum pump would be installed in and
around the Chemical Storage Tank area such that the Cones of influence would extend over the entire
CODtamin~ed area. A series of injection wells connected to a blower or vacuum pump would be
placed in and around the Chemical Storage Tank area and used to induce air flow through the soil to
strip and volatilize the VOCs into the air stream. Subsurface air, VOC vapors, and water vapors
would migrate toward the vacuum extraction wells in response to the negative pressure gradient
around the well.
RE:012~\maniD\rod45-99
93"
-------
.'
... .. -- .
Veauum EldrMtion.
Ip88m
Vepor to .
C8rbOn AdIOqItIon
rN8l108l'lt .
......... d InIeCdon
.. .8118
FIGURE 8.3. MARTIN MARIE'ITA ASTRONAUTICS GROUP.
o .
SELECTED REMEDY FOR CHEMICAL STORAGE AREA
IN-SITU VAPOR EXTRACTION
-------
September 19, 1990
The CODtAminAted air and vapor would flow to a vaporlliquid separator where CODt2min2ted
water would be removed.. The conuminated water would be treated to meet COPDES limits in
MMAG's industrial waste water treatment plant. The cont2min2ted air stream would be treated to
reduce VOC concentrations to air quality standards. Air emissionS would be monitored and
additional controls would be incorporated as necessary.
Soil vapor extraction is expected to achieve an estimated 99~ removal of VOCs which will
provide long term protection of the ground wate{by further reducing the potential for contAminAnt
leaching into the saturated zone.
8.1.2 Alternative GW-4: Continued Operation of Existing Recovery Well SystemslInstallation
of Additional Recovery Well Systems In Filter Gulch and Dry Gulch Upgradient From
the Existing Recovery Well Systems/Addition or a Recovery Well System in the M3
ArealTreatment By Chemical Reduction, Precipitation, Clarification, Air:' Stripping,
Carbon Adsorption, Ion Exchange, and/or UV Photolysis-OxidationIDiscbarge to Brush
Creek - .
Because the ground water supplied both domestic and agricultural water, and there is a
.
potential for the ground water to be used for these purposes in the future, alternative GW -4 is
. selected to restore ground water to its beneficial uses. Presently, the ground water is cont2minated
with VOCs, semi-volatiles and chromium at levels that pose significant health threats were the water
used is for domestic purposes. .
Ground water Alternative GW-4 will preclude contAminated migration off-site in the alluvial
ground water by removing organic and inorganic contaminants from the alluvial ground water to
meet remediation goals. Additionally, ground water in the Fountain Formation in the vicinity of the
Chem Mill and Hydrostat Tank areas highly contaminated with VOCs and chromium will be
collected and treated.
The ground water response action is generally limited to the alluvial system, except for
ground water in the M3 area. The basis for this decision is the fact that bedrock flow is extremely
low relative to the alluvial flow, conumina~ migration is primarily directed down-dip and
subsequently confined by a shale formation as described in section 4.3.1. Additionally, bedrock
would not yield sufficient water to be used for domestic or agricultural purposes. However,
monitoring of bedrock and alluvium will be conducted to evaluate migration of contaminants in the
bedrock, and remediation goals are likely to be met at some point in the future as a result of natural
attenuation and the other response actions.
RE:Ol2-C:08902'-rIiD\r0d45-99
95
-------
Rl!CCM!Rf 8'ftI1'IIi .
'Cf.. .
~""'.8 ,.....
't
N
,
. ,
'.
"'80.
. .
,........ u...
. .
....
....... M"'" ......
.. bhtInt 8..... .
---6 .:'"
'ller 0""" -.-
\ "
F'lGURE 8-4. MARTIN MARIE1TA ASTRONAUTICS GROUP
PROPOSED GROUND WATER RECOVERY SYSTEMS
-------
September 19, 1990
The ground water will be recovered from the five systems and pumped to the IWI'P in the
MJ area where organic and inorganic contaminants will be removed. The IWTP would include air
stripping, carbon adsorption, ion exchange, UV photolysis/oxidation, chemical reduction, precipita-
tion, and clarification processes. Ground water may be treated separately through some of the
processes. Only, chromium contamin!lted water would proceed through the chromium removal step.
The treated effluent would be discharged to the Brush Creek MMAG waste water outfall (COPDES
Permit #0001511), located approximately 100 feet downstream of the Brush Creek recovery system,
as shown in Figure 8-4.
Ground water modeling indicates that ground water restoration time frames required to attain
restoration goals are approximately 45 years for on-site ground water and in excess of 5 years for
off-site ground water. The model assumes that sources of contamination are completely removed.
Given this assumptions and others, the length of time required for ground water restoration is only
an estimate.
Ground water monitoring will be conducted semiannually, at a minimum, through sufficient
number of wells to track contaminant migration from the site to assess potential risks. Exact well
locations will be determined during the design phase. The monitoring would be done in the
following areas:
MJ, Filter Gulch, and Kassler:
Alluvium. .
.
Up and down-gradient of the Evaporation Pond
In the central M3 area near Mod C along Filter Gulch, both above and below the
Filter Gulch recovery system
At the mouth of Filter Gulch in the Kassler area
.
.
Bedrock
.
Downgradient from the Chemical1'anks at the north door of the factory
Downgradient from the evaporation pond
In the central M3 area near Mod C
.
.
.
Downgradient from the former location of the EHT
On the south side of Filter Gulch, southeast of the Evaporation Pond
.
RE:Ol2-C08002\maniD\rod45-99
96
-------
.
September 19, 1990
. Along Filter Gulch, both above and below the existing Filter Gulch recovery system
At the mouth of Filter Gulch in the Kassler area
.
Inactive Site Area:
Alluvium
.
Along alluvial ground water pathways directly north of the ponds approximately 400
feet downgradient (south) of Pond 1
Along Dry Gulch at locations approximately 1,000 feet, 2,100 feet, and 4,000 feet
downgradient of the ponds
Along the West Branch of Brush Creek approximately 300 feet south-southeast of
Pond 1
.
.
Bedrock
.
Approximately 180 feet north of Pond 4
Along the West Branch of Brush Creek, 300 feet south-southeast of Pond 1
.
..
Approximately 400 feet south-southeast of Pond 1
Along Dry Gulch at locations 1,000 feet, 2,100 feet, 2,700 feet, and 4,000 feet
south-southeast of the ponds
.
.
In the Lyons Sandstone 1,000 feet east-northeast of the ponds
Brush Creek (East and West Branches) and Kassler:
Alluvium
.
Along the West Branch at the confluence with Dry Gulch
Above and below the Lower Brush Creek recovery system
.
.
Along the East Branch, downgradient from the Rifle Range Landffil
Along the East Branch above the confluence with the West Branch
.
.
In the South Platte alluvium along Brush Creek, near the S-sided well and upgradient
from the Department of Wildlife ponds
Bedrock
.
Along the West Branch at the confluence with Dry Gulch
RE:012-C08002\martiD\rod4S-99
98
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September 19, 1990
.
. In the Glennon Limestone near the West Branch
In the South PlattelLytle Formation below the Lower Brush Creek recovery system
Downgradient from the Rifle Range Landfill
.
.
North Central Valley:
Alluvium
.
Along the southern extension of Lariat Gulch, 800 feet north of the Air Force
property boundary and 1,600 feet north of the boundary at the confluence of the
southern extension with the main branch of Lariat Gulch
Bedrock
.
Along the southern extension of Lariat Gulch 800 feet north of the Air Force
property boundary
The RCRA Part Band Post-closure permits will place restrictions on the installation of new
grc:,.tnd water supply wells and provisions for MMAG to provide an alternate water supply should the
need arise during the implementation of alternative GW-4.
One of the new recovery systems will be installed in Dry Gulch in a more highly
. contaminated area, approximately 3,500 feet southeast of the Inactive Site, and another will be
installed in Filter Gulch southeast of the M3 area, approximately 200 feet north of the MMAG
property boundary. ,The new recovery system in Dry Gulch will probably consist of a trench and
well system similar to the existing Brush Creek system. The new system in Filter Gulch would
probably consist of a line of recovery wells similar to the existing Filter Gulch system. Water
purchased from the Denver Water Department would be recharged into the alluvium at Dry Gulch
and the M3 area to enhance extraction rates and flushing of the alluvium for more rapid restoration.
Additionally, a recovery system will be installed in the Clean Mill Sumps and extraction wells will
be placed near the H1T area.
It may also be necessary to install an extraction system upgradient of the Inactive Site
recharge system to collect ground water located between the ponds and the recharge system. The
need for such a system would be evaluated during the design phase. Figure 8-4 provides a summary
of all the ground water recovery system locations;
Extracted ground water will be treated by chemical reduction, precipitation, air stripping,
carbon adsorption, ion exchange, and UV photolysis/oxidation, chemical reduCtion, and chemical
RE:Ol1.co8OO1'-rliD\r0d.45-99
99
-------
September 19, 1990
precipitation (S~ Figure 8-S). The process design and final methods of tteatment will be determined
during design phase.
Air stripping is a widely used process for removing VocS from aqueous stteams. The degree
to which the contaminant enters the gaseous phase depends on a combination of physical and
chemical characteristics of the contaminant such as the diffusivity, molecular weight, solubility, and
vapor pressure, as well as the design of the aeration system employed. One of the more important
characteristics of a volatile organic compound is its Henry's Law constant. The greater the Henry's
Law constant for a particular VOC, the easier a VOC is removed from water by aeration. The
Henry's Law constant is a function of temperature, therefore, the water temperature will also affect
the amenability of a contaminant to removal by aeration.
Air stripping is generally used to remove VOCs that have a Henry's Law constant greater
than 3.0 x Ut' atm-mJ/mole from aqueous liquids and would effectively remove ground water
contaminants such as TCE, DCE, and toluene found at the MMAG site.
The air stripping system in use at MMAG is a counter-current packed tower. Water is
inttoduced at the top of the tower and flows by gravity through packing media, which serves as the
mass transfer surface area. At .the same time, air is blown upward through the tower in a counter-
current flow. The air is exhausted through the top of the tower. The process transfers organic
CODtaminal\ts from the wastewater to the air sttearn. The tteated effluent is removed from the
bottom of the tower, col~ected in a sump, and pumped to the carbon adsorption unit.
The principal environmental concern associated with air stripping is the generation of volatile
organic air emissions. As part of the final remedy, EP A and CDH have decided to include, as part
of the air stripping process, an activated carbon adsorption emission conttol system. The emission
conttol system is added to comply with the national policy (OSWER Dir. 9355.0-28) calling for
emission conttols for air sttipping in areas of non-att.ainment with respect to ambient air quality
standards. Additionally, the response actions are intended to reduce contaminant toxicity, mobility or
volume in the environment and not cause cross-media CODtamin:at10n. This decision is not based
solely on cancer risk considerations. The justifications for this decision include community
acceptance and the need to control VOC emissions to red~ce atmospheric impacts on ozone.
Liquid effluent from the air sttipper will be sent to the carbon adsorber. Carbon adsorption
removes the organic contaminants ,from the liquid sttearn by absorbing them onto a high surface area
activated carbon bed comprised of either granular or powdered carbon. Activated carbon will also
RE:012-c0&002\ma11i11\rod4S-99
100
-------
AIR STRIPPER
c--. v.......
..... (' . ..)
~(;J
, I I IIJr v....
..+ .."'. L -
:....'w-::~ TD .' ~
CARBON
ADSOeER
ca-0IwMk
":'. ' )
11V PHOTOL YSJSI
OX!DAnON . JON EXCHANCE
~ama. ca-.....)
"IIDMA)
~ :'''''''' ~+b:~-~ 5.2-
..... eu-. D vy..- .........
..--~ ~ 0.. -. "",.,OCIIIII ~
.~.
. .
Note: Process fJow scheme is rcprc:semative of remedy but will be
. subject to the results of pe«siga Studies.
FIGURE 8-5 - MARTIN MARIE1TA ASTRONAUTICS GROUP
SELEl:UW REMEDY FOR GROUND WATER CONTAMINANT
TREATMENT PROCESS
-------
September 19, 1990
adsorb most metals chelated with organic compounds. Factors affecting the adsorption process
include the carbon pore strUctUre, carbon contact time, temperature, and pH. Treated effluent from
the carbon adsorber would be next processed in the UV photolysis system. Used carbon material
would be periodically regenerated or disposed off-site.
Ultra-violet (UV) photolysis is a process that uses UV radiation to destroy or detoxify
organic cont~min~nts in aqueous solutions. Oxidation is combined with UV photolysis to enhance
the efficiency and rate of the reactions for compounds that are difficult to oxidize. UV photolysis
will be used at MMAG to remove NDMA and UDMH from the ground water.
Treatability studies will be required to select the appropriate design for the UV IOxidation
process. Several options exist which include using solar and lamp generated UV light.
The ion exchange process equipment consists of columns co~g solid ion exchange
resins. These resins contain charged surface sites that are initially occupied by weakly held
monovalent anions or cations such as chloride, hydroxyl, sodium, or hydrogen ions. The
contaminant ions displace the original ions from the exchange sites and are removed from the
wastewater stream as a result of high affinity for the charged sites on the surface of the resins.
Exchange resins are reversible, and are periodically regenerated for reuse. Both anions and
cations can be removed from the ground water stream by placing a cation exchange column and
anion exchange column in series. This type of system would have the capability to remove a wide
range of inorganic dissolved contaminants such as metallic anions and cations, halides, sulfates, and
organic acids and bases. The exact configuration of the ion exchange process will be determined
during design.
Regeneration of ion exchange resins produces a concentrated solution of contaminants that
may require treatment prior to disposal.
Reduction/oxidation may be used to treat hexavalent chromium in the ground water. In this
process the oxidation State of one reactant is raised while the other is lowered. This process is used
to reduce the toxicity of hexavalent chromium by converting it to the trivalent state. Typical
reducing agents used in the process are ferrous sulfate, sulfur dioxide, and sodium ch1orohydride.
The chemical precipitation step is a physicochemical process through which some or all of a
substance in solution is transformtid into a solid phase. Precipitation would follow the chemical
reduction phase to separate the solid metals from the liquid phase. The process is based on altering
102
RE:012~\martiD\rod99-.cad
-------
September 19, 1990
the chemical .equilibrium relationships affecting the solubility of inorganic species. Precipitation
would be used to remove the chromium and other metals from solution. Other inorganic
cootaminJnts such as phosphate, sulfate, aDd fluoride would be removed as necessary.
The removal of metals would be accomplished throujh the addition of lime, sodium
hydroxide, or sodium sulfide to the water in a rapid mixing tank along with flocculating agents. The
water would be introduced to a flocculation tank where it would be mixed and retained to allow for
agglomeration of precipitate particles. Sedimentation or clarification wo~d be used to settle out the
sludge. Precipitation is nondestructive aDd generates a large volume of sludge that must be disposed.
Sludges, waste residues, and spent carbon resulting from the treatment of the ground water
would be analyzed for contaminJnt content and disposed of accordingly. Sludges will be disposed at
an off-site permitted hazardous waste TSD facility. Spent carbon aDd ion exchange resins would
either be recycled (regenerated), and/or disposed off-site.
The treated effluent discharged from the MMAG IWTP will meet the required treatment
standards, specified in MMAG's COPDES permit. Modifications to the permit resulting from
implementation of this remedy are not expected With the exception of the limit for NDMA which
may be lowered.
8.2
REMEDIATION GOALS
The selected..remedy includes: (I) removal aDd treatment of waste aDd contaminated soil in
and around the Inactive Site Ponds which act as the contamil'lation source to the ground water; (2) in-
situ removal of chlorinated hydrocarbons from the soil in the Chemical Storage Tank area; (3) and
recovery and treatment of contamin8ted ground water on a site-wide basis (excluding Lariat Gulch).
The remediation goals are set at concentrations based upon chemical-specific ARARs which will
achieve drinking water standards and provide long term protection of the ground water through
source control measures. Additionally, the removal aDd containment of .CODt2minants in soil on-site
will prevent future uncontrolled exposure to humans and wildlife. Finally, the remedy wiJI protect
the recreational uses of adjacent areas by preventing contaminant loading on the down gradient
environment both in. the short term during implementation and in the long term after remediation
goals are achieved.
The remediation goals are set at levels necessary to provide long-term protection of human
health and the environment with, to the extent possible, unrestricted use of the site and adjacent areas
and water migrating from the site.
103
RE:012..c0a0D2'-"iD\rod99-.11111
-------
September 19. 1990
8.2.1 . Soil Remediation Goals (inactive Site and Chemical Storage Tank Areas)
The remediation goals for the Inactive Site Pond area are as follows:
1.
Dewatering of the Inactive Site Pond area to remove contaminated perched and
alluvial ground water to allow for. the subsequent removal and treatment of waste and
contaminated soil (alluvium and backfill). This water will be treated to meet the
COPDES permit standards before discharge. The limits set in the COPDES permit
(No. COOOOOI511) are protective of human health and the environment.
The waste sludge that is readily differentiated from soil (i.e.. based upon visual
inspection) will be separated from the contaminated soil (backfill and alluvium) and
transported off-site for treatment and disposal at a permitted hazardous waste TSDF.
The waste will be identified as restricted waste subject to all RCRA LDRs standards
for treatment and disposal (40 CPR Parts 264 and 268). The off-site facility must
comply with section 121(d)(3) of CERCLA. .
2.
3.
The soil that is contaminated with the hazardous substances/constituents from the
wastes will be treated to meet the standards. as describ~ below. and replaced in the
area of contamination. .
Soil in the Inactive Site area will be analyzed to determine if it meets action levels. The
action levels for contaminated soil are based upon both the RCRA Toxicity Characteristics (TC)
determination established in 40 CPR Part 261 and background concentrations. The numerical
standards for each hazardous substance/constituent are determined by the application of the Toxicity
Characteristic Leaching Procedure (TCLP). These action levels are selected as being protective of
the water resources on- and off-site and reducing the potential for exposure through other pathways.
The TC-based action levels were developed using health-based concentration thresholds
including MCLs. RIDs and Risk-Specific Doses (RSDs) for drinking water
-------
September 19, 1990
scale treatability studies conducted during the remedy design phase demoDStJ'3te that it is not possible
or cost-effective to achieve the LDR treatment standards for listed waste, a new treatment standard
will be established base upon the soil and debris treatability variance process for CERCLA response
and RCRA corrective actions (OSWER Directive 9347.3-o6FS, July 1989).
The soils in the Chemical Storage Tank area will be treated in-situ removing VOCs to
approximately 99% removal. The target clean up level will be the LDR treatment standards or an
appropriate level based upon soil and debris treatability variance guidelines.
8.2.2 Ground Water Remediation Goals
The remedy selected for the ground water is designed to address contaminated ground water
emanating from both source areas identified during the RIlFS and units regulated under RCRA
program. In this way, the remedy is a site-wide "'rogram to address ~e most significant ground
water contamination in the alluvium and a portion of the bedrock in the M3 area.
Because ground water at and near the site is a potential source of drinking water, the
remediation goal for both on- and off-site is set to allow use of the ground water as drinking water.
The chemical-specific levels are based upon MCLs and MCLGs under the Safe Drinking Water Act,
Colorado Secondary Drinking Water Standards, Colorado ground water standards, and health based
concentrations (for NDMA)(see Table 8-2). Where a CODtaminant has more than one standard the
most stringent applies. (Only MCLGs greater than zero are relevant and appropriate.)
The selected remedy including treatment of contaminated soil and ground water is intended to
restore ground water to its beneficial uses which included drinking water and agricultural supply.
The data obtained during the RI and evaluation of the remedial alternatives support the conclusion
that it is possible to achieve the remedial goal. The remedy will be implemented with the intent of
achieving this goal. However, it may become apparent during the operation of the remedy that
contaminant levels have ~:~ to decline and are remaini"g constant at levels higher than the
remediation goals. In such a case, the system performance standards and/or the remedy may be
reevaluated based upon the data collected during the regw.:1l' monitoring program established as part
of the remedy.
A potential technical limitation may prevent the remedy from achieving the remediation goal
for NDMA in the ground water. The 10E-6 cancer risk from NDMA ingestion assuming exposure
in drinking water is estimated at 0.0007 ugll. Using the best available analytical procedures, the
existing reliable quantification limit for compliance monitoring is approximately 0.07 ugll NDMA in
105
RE:012.coaOo1\martin\rod99-.cnd
-------
September 19, 1990
TABLE 8-2
-.
MARTIN MAlUETl'A ASI'RONAurICS GROUP SITE
GROUND WATER CLEAN-UP STANDARDS
Cont2miftJl1t
Of Concern
Ground Warern)
Concentration (usrfl)
MCLGsCSl
(usrfl)
ORGANIC CHEMICALS
Benzene
1,2-Dichloroethane .
1,l-Dichloroethylene
N-Nitrosodimethylamine
1,1,1- Trichloroethane
Trichloroethylene
Vinyl chloride
INORGANIC CHEMICALS
5
5
7
0.0001C!
200
5
2
o
o
7
-(~
200
o
o
Arsenic
Barium
Cadmium
Chromium
Copper
Cyanide (free)
Fluoride
Iron
. Lead (MCL = 5 @ source)
Manganese
Mercury
Nitrate
Nitrite
Silver
Zinc
50(2) 0
1,000(1) 5000
5 5
50(1) 100
1,00001 1300
200 200
4,000 4000
300°1 - (~
5 0
SOCJ) - (~
2 2
10,000 10,000
1,000 1,000
50(2) -(~
5,000°1 - (~
References
1.
Standards taken from (unless otherwise noted) Safe Drinking Water Act Maximum
Contaminant Level (MCL), Drinking Water Regulations and Health Advisories, EPA Office
of Drinking Water, Washington, D.C., April 1990.
Colorado Human Health Standards for Ground Water, Colorado Water Quality Commission,
The Basic Standards for Ground Water, Section 3.11.0, January 15, 1987.
2.
3.
Colorado Secondary Drinking Water Standards, Colorado Water Quality Commission, Basic
Standards for Ground Water, Section 3..11.0, January 15, 1987.
Based on the Integrated Risk Information System (IRIS). (Also equivalent to the cancer risk
level of 10E~ for drinking water). .
Standards taken from the Drinking Water Act Maximum Cont2minant Level Goal (MCLG),
Drinking Water, Regulations and Health Advisories, EPA Office of Drinking Water,
Washington, D.C., April 1990.
4.
5.
6.
MCLG standards not set for these constituents.
106
RE:012-COBOO2\Manin\rodlbl.B-2\alc
-------
September 19, 1990
water ~ This corresponds to a 10E~ cancer risk. The ability to treat ground water to remove
NDMA to a concentration equal to or less than 0.07 ugll has yet to be demonstrated.
Changes or adjustment to the design or operation of the ground water recovery and treatment
systems may be necessary to achieve the remediatjon goals. This will be determined aftaer
implementation and subsequent evaluation of remedy performance.
8.3
REVISED COST FSI1MATE
Table 8-3 is a summary of the total estjm~ted cost for the selected remedy.
9.0 STATUTORY DETERMINATIONS
The selected remedy will comply with all applicable action-specific, chemical-specific and
location-specific ARARs.
The selected remedy is consistent with requirements of CERCLA (as amended by SARA) and
the NCP. Under Section 121(b) of SARA the selected remedy must satisfy the following
fundamental criteria:
1.
2.
Protection of human health and the environment
3.
Compliance with ARARs or justify a waiver
Cost-effectiveness
4.
Use permanent solutions and alternative technologies or resource recovery
technologies to the maximum extent practicable .
Satisfy the preference for treatment to reduce toxicity, mobility. or volume as a
principal element, or provide an explanation as to why this preference is DOt satisfied
s.
'.1
PROTECI'ION OF HUMAN HEALTH AND THE ENVIRONMENT
If EP A were to select the No Action alternative as the remedy. the cont2mjn:ants on-site
would continue to be released to ground water and CODt2mjn:ant migration would result in further
degradation of water resources on-site and off-site. Ecological impacts could result in the South
Platte River and the Chatfield Reservoir. The potential for human exposure to the contamjn:ants
would increase and the ground water would remain useable in the future. If ground water were used
for domestic purposes, the health risks would exceed acceptable levels for cancer and noncancerous
107
RE:012~\awtiD\rod99-.eDd
-------
~'
TABLE 8-3
MARTIN MARlenA ASTRONAUTICS GROUP SITE
TOTAL ESTIMATED COSTS FOR SElECTED REMmV
September 19, 1990
CAPITAL COSTS
ALTERNATIVE S-5: DEWATERIEXCAVATEIINCINERATE AND DISPOSE OF WASTE OFF-SITE/THERMALLV EXTRACT CONTAMINATED BACKFILL. ALLUVIUM/EX-SITU
STABILIZE CONTAMINATED BACKFILL. ALLUVIUMIRCRA CAPliN-SITU SOIL VAPOR EXTRACTION .
ITEM
ESTIMATED
QUANTITY
eo will point.
ALTERNATIVE
TOTAL cost
1.
2.
Extrectlon wen.
UNIT PRICE
1830
COST
150,000
'1,900.000
'800,000
. .
3.
Excevetlon
Trensportedon 0' We.te
47.500 cy
2.200 cy
185 trips
40/cy
3,4OO/trip
4.
Inclnerete end DI,poII 0'
We.te Off.Slt.
Therrnel Extrectlon
et contemlnetad beckflll
bt elluvlum
2,100 cy
1,8oo/cy
3.800,000
&.
9.700 cy
14,700 cy
425/cy. .
4.100.000
8,200,000
8.
Stebllizedon
et contemlnetad beckflll
bt elluvlum .
RCRA capplna
275/cy. .
40/.q yd
3.400 /trip
2.700,000
4,000,000
1,800,000
9.700 cy
14,700 cy
45,000 .q yd
750 cy
eo trip.
7.
8.
200,000
Trensportedon 0'
Sludge Re.ldue
Inclnerete end DI.po.e 0'
R..ldue Off.Slte
Fence
3.500 h
101ft
35,000
9.
750 cy
1,800/cy
1.400,000
10.
11.
Soil Vapor Extreodon emeteriel. .nd In.t.ll.don
co.t. 'or vecuum well. end pumpst
85,000
SUBTOTAL
128,885,000
5,377.000
12.
13.
Contlnaency e4J 20"t
Engineering, Legel.
Admlnlstretlon C@ 25"t
8,721.000
ALTERNATIVE S.& TOTAL
t38,983.000
t38.983,OOO
108
-------
TABLE B-3 Ccontlnued'
MARTIN MARIETTA ASTRONAUTICS GROUP SITE
TOTAL ESTIMATED COSTS FOR SELECTm REMEDY
CAPITAL COSTS
E8T1MATm
ITEM QUANnTY
AL TERNA TlVE GW-4: PUMPlNGJEXTRACTlON/TREA TMENT SYSTEM
UNIT PRICE
COST
14. Extraction SVitema
15. Piping CChem MID Are.'
Piping CRemalning Are.'
18. Pipe Trench
17. Air Strfpper SVitem
18. Actlvlt,.oJ Cerbon filter SVitem
19. UV/Ozonatlon SVitem
20. Building Encloeure
21. Utilitlee
22. Contlngenctea CO 20",
23. E~n'.~ng, Lel~'
Admlnletratlon .0 25'"
'580,000
1,500
24,500
1.000 ft
7,000 ft
5,700 ft
., .50lft
U.50/ft
".50lft
7,800
SUBTOTAL
38,000
27,500
184,000
60,000
. 30,000 .
'905,000
181,000
228,000
ALTERNATIVE GW'" TOTAL
.1,300.000
SELECTED REMmy TOTAL CAPITAL COST
'\
September 19, 1990
TOTAL COST
. 1.300.000
'40.283,000
-------
c
TABLE 8-3 lcontlnuedl
MARTtN MARlEnA ASTRONAunCS GROUP SITE
TOTAL ESTIMATED COSTS FOR SaECTED REMEDY
OPERATION AND MAINTENANCE COSTS
September 19, 1990
ALTERNATIVE S-5: DEWATERIEXCAVATEJlNCINERATE AND DISPOSE OF WASTE OFF-SITEITHERMAUY EXTRACT CONTAMINATED BACKRU. ALLUVIUMlEX-SniJ STABIUZE
CONTAMINATED BACKFILL. ALLUVIUMIRCRA CAPliN-SITU SOIL VAPOR EXTRACTION
TOTAL ANNUAL
ITEM ANNUAL COST O.M COST
1. Ground Wltlr Semp\lng . Anelyall '17,000
2. Cep Melntlnenc8 50,000
3. Report. Preplrldon 10,000
4. Flncl Repelrl 4,000
6. Ground Wltlr Sempllng . Anelyall 6,000
8. Equlpmlnt Repelrl 1,000
7. Electrtclty 1,000
8.. Report P~eplrldon 3,000
9. Contingency (0 20~1 18,000
10. Englneertng, legel, Admlnlltrldon
(@I 25"1 . 23,000
ALTERNATIVE 8-6 TOTAL
'132,000
'132,000
110
-------
TABlE 8-3 lcontlnuedl
MARTIN MARIETTA ASTRONAuncs OROUP sm
TOTAL EsnMATm COSTS FOR SElECTm REMmv
OPERAnON AND MAINTENANCE COSTS
September 1., 1990
AL TERNA nVE GW.4: PUMPING EXTRAcnONITREA TMENT SYSTEM
mM
11.
12.
Extrecdon SVltlm8
Piping, lnapecdon, Teldng
end M8Intenence
13.
14. .
Trletnient SViteml
Ground Weter Monitoring
15.
18.
SUBTOTAL
Condngenoy 10 20".
Engineering, Legel a Admlnlltredon
I@I 25".
ALTERNAT1VE OW... TOTAL
SElECTED REMmV TOTAL OaM COSTS
'SUMMARY OF SElECTED REMmV
TOTAL CAPITAL COSTS
TOTAL OPERATION AND
MAINTENANCE COSTS
. TOTAL COST. Nit Pre.ent V.....
ANNUAL COST
887,000
7,000
580,000
'158,000
8790,000
'158,000
'198,000
'1.100,000
'1.232.000
'40,283,000
'1,232,ooo1YR
INet preeent velu. celculeted ullng 5" dl.count v8lue end e 30 yeer
project life, pre.ent worth fector - 15.37251
'69,222.000
TOTAL ANNUAL
Oa.M COST
.'.'00.000
.'.232.000
"11
-------
September 19, 1990
"
. threats em O!her words cancer risks above 1 x 10"').
The selected remedy will substantially decrease the release and threat of release of hazardous
substances, pollutants and contaminants from the soil and ground water at the Site. The current
threats and any potential future threats associated with domestic use of the ground water will be
addressed by treating and removing the sources of ground water contamination and treating the
ground water to m~ drinking water standards. In terms of short term effectiveness, the remedy is
adequate as there are no current users of the ground water., an alternate water supply will be
provided if needed, and. contaminant migration and release will be reduced with the implementation
of the remedy. Threats to the environment or human health on and around the site are not expected
during the implementation of the remedy because the emissions and discharges will meet health based
and regulatory standards.
o
Achieving the goals of remediation for the ground water remediation is estimated to require
4S years. However, the source control measures at the Inactive Site Ponds will be completed in
approximately 4 years. The combination of two alternatives will provide short-term and long-term
protection of the environment and human health.
As an additional measure, because the selected remedial action results in hazardous
substance, pollutants or contaminants remaining at the site, the remediation will be reviewed at least
every S years after the initiation of the remedy to assure human health and the environment are being
protected. .
. 9.2
COMPLIANCE WITH APPUCABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs) OF ENVIRONMENTAL LAWS
Under Section 121(d)(1) of the CERCLA, remedial actions that leave any hazardous
substance, pollutant or contaminant on site must attain a level of control that at least attains
standards, requirements, limitations, or criteria that are wapplicable or relevant and appropriate-
under the circumstances of the release. A remedial action that does not attain ARARs may be
selected only if a statutory waiver is available and determined to be appropriate.
W Applicablew requirements are those clean-up standards, standards of control and other
substantive envirOnmental protection requirements, criteria, or limitations promulgated under Federal
or State law that specifically address a hazardous. substance, pollutant or contaminant, remedial
action, location, or other circumstance at a remedial action site. wRelevant and appropriate W
requirements are clean-up st3ndar~ of control and other substantive environmental protection
requirements, criteria, or limitations promulgated under Federal or State law that, while not
112
RE:012~~\manin\rod99-.end
-------
September 19,.1990
Wapplicablew1Q a hazardous substance, pollutant, CODt2min:ant, remedial action, location, or other
circumstance at a remedial action site, address problems or situations sufficiently similar to those.
encountered at the site that their use is well-suited to the particular site. See the NCP (40 CPR
Section 300.430) for further information.
The selected remedy will comply with all applicable or relevant and appropriate action-
specific, chemical-specific and location-specific ARARs (fable 9-1). The action-specific ARARs
apply to operating specific technologies such as incineraqon or landfilling of hazardous waste.
Chemical-specific ARARs are those which set limits on concentrations for individual chemicals such
as MCLs for drinking water. Finally, the location-specific ARARs relate to activities that are
restricted . from occurring based upon site conditions such as flood plains or wetlands.
9.2.1 Resource Conservation and Recovery Act (RCRA) and Toxic Substance Control Act
(TSCA)
Off-site transportation, treatment, storage and disposal of listed hazardous waste and PCBs is
subject to RCRA, TSCA and CHWA and applicable regulations, as well as Section 121(d)(3) of
CERCLA.
On-site treatment of soil containing RCRA hazardous waste and other cont2minants, 8nd the
.redepositing of the treated soil in the area of contamin:ation, will attain ARARs under RCRA. The
waste removed from the area of contamination will be treated and disposed off-site. The soil will be
treated to meet LDR standards (for the listed waste type) or protective standards based on a soil and
debris treatability variance.
RCRA requirements are applicable because soil excavated and treated (by stabilization) will
contain a hazardous waste and will be redeposited in the area of CODt2min:ation. (CERCLA
Compliance with Other Laws, Draft, U.S. EPA OSWER Directive 9234.1~t', August 1988).
Closure standards for landfills and surface impoundments are applicable. However, redepositing the
treated soil in the area of cont2min:ation does DOt trigger minimum technology requirements because
it is not a replacement. unit and DO additional waste from outside the unit is added (Superfund
Records of Decision Update, U.S. EPA Publication 9200.5-2161, June 1990). Therefore, the design
and operating requirements for Subtitle C landfills (40 CPR Section 301) are not applicable. Also,
the RCRA storage unit requirements are no; ~pllcable for the purposes of accumulating sufficient
waste prior to.treatment (U.S. EPA, OSWER Directive 9234.1~1 August 1988, p. 2-12).
Furthermore, the material that is iaentified as waste and the organic contamination extracted from the
soil will be shipped off-site for treatment and disposal in accordance with RCRA land disposal
113
JtE:012-c0s602'-"iD\rod99-.ead
-------
TABLE 9-1
MARTIN MARIETTA ASTRONAUflCS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Standard, Requirement
Criteria. or L;mitation
A. Federal Contaminant Specific ARAR's
Safe Drinking Water Act
National Primary Drinking Water
Standards
National Secondary Drinking
Water Standards"
Maximum Contaminant Level Goals
Clean Water Act
Citation
42 V.S.C. 11300f-
300j-26
4OC.F.R.
Part 141
40 C.F.R.
Part 143
Pub. I. No. 99-339,
100 Stat, 642 (1986)
33 V.S.C.
111251-1316
Description
Applicable!
Relevant and
Appropriate
Establishes standards for
drinking water
NONES
NONES
Establishes standards
for public water supply
systems (maximum con-
taminant levels).
Establishes welfare-based
standards for" public water
supply systems (secondary
maximum contaminant levels).
NONES
Establishes drinking water
quality goals set at levels'
of no known or anticipated
adverse health effects, with
an adequate margin of safety.
NOIYES
114
~
September .. . 1990
Comment
Relevant and appropriate for
ground water that is current or
potential source of drinking
water .
MCLs are relevant and appro-
priate for ground water that is
current or potential source of
drinking water.
SMCLs are relevant and
appropriate for ground water
that is a current or potential
source of drinking water. For
states that have adopted
SMCLs as additional drinking
water standards, SMCLI are
potential ~tate ARARI.
MCLGs above zero are rele-
vant and appropriate for"
ground water that is or may be
used for drinking. MCLGs =
zero are TOC. "
RE:OI1.c08002\maltla\rocllbI.9-I
-------
Standard, Rc:c\uirement
Criteria. or Limitation
Water Quality Criteria
Clean Air Act
National Ambient Air Quality
Standards (NAAQS)
National Emissions Standards
for Hazardous Air Pollutants
(NESHAPs)
TABLE 9-1
MARTIN MARIE'lTA ASTRONAUfICS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
40 C.F.R.
Part 131
42 V.S.C.
IG 7401-7642
40 C.F.R. Part SO
40 CFR Part 61
NONE
. B. Federal Location Specific ARAR's
,
C. Federal Action Specific ARAR's
.
Solid Waste Disposal Act rSWDA-)
40 V.S.C.
iI 6901-6987
Description
Provides for establishment
of water quality based on
toxicity to aquatic organisms
and human health.
Establishes standards for
ambient air quality applic-
applicable to air emissions
from cleanup operations.
Sets emission standards for
designated hazardous pollu-
tants .
115
Applicablel
Relevant and
Appropriate
NONES
YES/-
YES/-
September 19, 1990
Comment
FWQC for human health are
relevant and appropriate for I
current or potential drinking
water supply." J prom-
ulgated MCL exists. ' "
Requirements related to attain-
ment of NAAQS are :fPlic-
able when the remedi
activity at a CERCLA aite
(e.g. air stripping is I major
source of emissions, consider-
ing the aggregrate of all
source emissions at the aite.
There exists proposed sources
at the site which will emit
hazardous' air pollutants.
RE:O 12-C08002\martiD\rocItb1. 9-1
-------
Standard, R~irement
Criteria. or Limitation
Standards Applicable
to Generators of
Hazardous Waste
Standards Applicable
to Transporters of
Hazardous Waste
Standards for Owners and
Operators of Hazardous
Waste
. General Facility
Standards - Financial
Requirements
. Use and Management
of Containers
. Tanks
TABLE 9-1
MARTIN MARIETTA ASTRONAUI1CS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
DescriDtion
40 C.F.R.
Part 262
Establishes standards for
generators of hazardous
waste (waste determination
and manifesting.)
Hazardous waste shipped
off-site must comply with
this section which adopts DOT
transportation standards and
manifesting requirements.
40 C.F.R.
Parts 262, 263
and 268
4OC.F.R.
Part 264
Establishes minimum
standards which define the
acceptable management of
hazardous waste for owners
and operators of facilities
which treat, store, or
dispose of hazardous waste.
Subparts B
through E
Subpart I
Establishes standards
for storage of hazardous
waste or materials
in containers.
Subpart J
Establishes standards for
use of tanks to treat or
store hazardous wastes.
116
Applicable!
Relevant and
AD~ropriate
YES/-
YES/-
YES/-
YES/-
YES/-
YES/-
September ~" 1990
Comment
Excavation or consolidation of
soU and sludge may constitute
generation of a RCRA hazard-
ous waste. .
Applicable where hazardous
waste is sent off-site.
Hazardous waste is treated
on and off-site.
If hazardous waste is treated,
stored or disposed of, the
regulation for design and
operation for that unit or
process are applicable.
If containers are used to store
waste, requirements will be
followed.
If waste is treated in a tank,
substantive standards apply.
RE:OI1-COSOO1\maltin\rodIbI.9-1
-------
Standard, Rt;qoirement
Criteria. or Limitation
. Surface Impoundments
. Waste Piles
. Llndfills
. Incineraton
. Land Disposal
Restrictions .
Hazardous Waste TSOF,. Organic
Air Emission Standards for .
, Process Vents, Equipment Leaks
Toxic Substances Control
Act
TABLE 9-1
MARTIN MARIE'lTA ASTRONAUfiCS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
. FEDERAL AND STATE
Citation
Description
Subpart K
Establishes standards to
treat, store, or dispose
of hazardous wastes.
Subpart L
Establishes standards for
storage or treatment of
hazardous waste in piles.
Establishes standards for
disposal of hazardous wastes
in a landfill.
Subpart N
Subpart 0
Establishes standards for
incineraton. .
Subpart C
Identifies hazardous wastes
restricted from land disposal
and circumstances under
which waste may be land
disposed.
Standards for emissions ,
from air stripping of VOCs.
40 CFR
Parts 264
Subpart AA
IS U.S.C.
iA 2601-2629
117
Applicable/
Relevant and
Appropriate
YES/-
YES/-
NO/NO
NO/NO
YES/-
YES/-
TBC
September 19, 1990
Comment
If waste is treated in . tank,
substantive standards Ipply.
Temporary storage prior to
treatment is not subject to
standards.
Oft'-site disposal is planned.
Oft'-site incineration is plan-
ned. Applies to TSD.of
wastes.
Aprlies to TSO. of waste and
soi containing waste.
Air stripping and therma( ex-
traction are employed by the
remedy.
For soil containing waste,
LOR levels are target for
clean-up.
RS:OI2-011002\m8rtJn\rodlhI.9-1
/
-------
Standard, Requirement
Criteria. or Limitation
PCB Requirements
Clean Air Act
National Emission
Standards for
Hazardous Air Pollutants
National Ambient Air
Quality Standards (NAAQS)
Occupational Safety
and Health Act
Hazardous Materials
, Transportation Act
Hazardous Materials
Transportation
Regulations
September "k. . ~990
TABLE 9-1
MARTIN MARIEITA ASTRONAUI'ICS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
4OC.F.R.
Part 761
42 U.S.CC.
IA 7401-7642
4OC.F.R.
Part 61
. 40 CFR
Part SO
29 U .S.C.
IA 65 1-678
49 U.S.C.
Ai 1801-1813
49 C.F .R. Parts
107, 171-177
Descriotion
Establishes storage and
disposal requirements for
PCB's. PCB's are not
present in significant
quantities at the site.
Sets emission standards for
designated hazardous pollu-
tants
Sets emission standards for
carbon monoxide, lead,
nitrogen, dioxide, parti-
culate matter, ozone, and
sulfur oxides.
Regulates worker health
and safety.
Regulates transportation
of hazardous materials.
118
Applicable!
Relevant and
Aooropriate
NOIYES
YES/-
YES/-
YES/-
YES 1-
Comment
. If PCBs are found at amcen-
trations above 50 ppm, these
will be applicable.
There exists proposed sources
at the site which will emit
hazardous air pollutants. .
Applicable to TSD facilities
and MMAG. MMAG is is a
non-attainment area.
Hazardous waste site activities
worker protection will. apply. .
(40 CFR 300.38)
These standards are applicable
to off-site transportation of
waste.
0:0 11-C08OO1\maltia\rocllb..9-1
-------
Standard, R~uirement
Criteria. or Limitation
TABLE 9-1
MARTIN MARlETrA ASl'RONAVTlCS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
D. State Contaminant $pecific ARAR's
Citation
Colorado Safe Drinking
Water Authorities
Primary Drinking
Water Regulations
Colorado Water Quality
Control Act
Basic Standards
for Groundwater
Basic Standards and
Methodologies
Anti Degradation
Standard
. .
C.R.S.
I 25-1-101(x), (y)
5 CCR 1003-1
C.R.S. fA 25-8-101
to -703
Section 3.11.0
5 CCR 1002-8
5 CCR 1002-8
Description
Establishes health-based
standards for public water
supplies.
Establishes a system for
classifying ground water
and adopting water quality
standards to protect exist-
ing and potential benefic-
ial uses.
Establishes basic standards
for introduction of sub-
stances attributable to .
human-induced discharges
into waters of the State.
Prohibits water quality
degradation which would
interfere with or become
injurious to existing uses.
119
Applicablel
Relevant and
. Appropriate
NOIVES
YES/-
YES/-
YES/-
YES/-
September .', .996
Comment
Treated ground water dis-
charged to surface water must
comply
Beneficial uses Include "domes-
tic aDd agricultural.
Discharges will occur u part
of the remedy.
RE:Oll~\marliD\roddII.9-1
/
-------
Standard, Requirement
Criteria. or Limitation
Ambient Air Quality Standards
E. State Location Specific ARAR's
NONE
F. State Action Specific ARAR's
C()lorado Hazardous 'Waste Act
(HW A)
Rules & Regulations
Pertaining to
Hazardous Waste
. Standards Applicable
to Generators of
Hazardous Waste
. Standards Applicable
to Transporters of
Hazardous Waste
September h, 1990
TABLE 9-1
MARTIN MARIE1TA ASTRONAUI1CS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND SI'ATE
Citation
S CCR 1001-14
C.R.S. 12S-1S-101
to -313
6 CCR 1007-3
Part 262
Part 99, 262,
263 and 268
Descriotion
Sets ambient standards for
total suspended particulates,
sulfur dioxide, oxidates,
carbon monoxide, and nitro-
gen dioxide.
120
Applicable!
Relevant and
Appropriate
Comment
YES/-
MMAG is in a non-attainment
area.
YES/-
These requirements wUl apply
to waste excavated and gener-
ated during the response
action.
YES/-
Off-site shipments of waste
must be manifested as hazard-
dous waste and comply with
all transportation standards.
RE:O 11.o18002\maltin\roclIbI.9-1
-------
Standard, Requirement
Criteria. or Limitation
. Standards for Owners
and Operators of
Hazardous Waste Treat-
ment, Storage and
Disposal Facilities
. Oeneral Facility
StalJdards - Financial
Requirements
. Release from Solid
Waste Management Units
. Closure and Post-Closure
. Use and Management
of Containers
. Tanks
September 19, 1990
TABLE 9-1
MARTIN MARIE'lTA ASTRONAtmCS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
Description
Part 264
See standards below
Subparts B
through E
Subpart F
Standards applying to
units which store waste
from which a release has
occurred (including
ground water monitoring
and protection standards).
Standards that apply to
the controls and monitor-
ing of waste in a unit
that is no longer operational.
Subpart 0
Subpart I
Establishes standards
for storage of hazardous'
waste or materials in
containers.
Subpart J
Establishes standards for
use of tanks to treat or
store hazardous wastes.
121
Applicable!
Relevant and
Approj)riate
Comment
NOIYES
YES!-
The Inactive Site Ponds are
SWMUs.
YES!-
Treated soil containing waste
returned to the area of con-
tamination is subject to these
standards. ' .
YES!-
If containers are used to store
waste, requirements wUl be
followed.
YES!-
If waste is treated in . tank,
substantive standards apply.
RE:OI2~\martin\rodtbI.9-1
-------
Standard, R~irement
Criteria. or Limitation
. Surface Impoundments
. Waste Piles
. L8ndfills
. Incinerators
. Colorado Financial
Requirements
Colorado Water Quality Control
Act
State Discharge
Permit Regulations
. CQlorado Air Quality Control
Act
TABLE 9-1
MARTIN MARIE'ITA ASTRONAUflCS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
Subpart K
Subpart L
Subpart N
SubpartO'
Part 266
C.R.S. II 25-8-101
to -103 .
5 CCR 1002-2
C.R.S. AI 25-1-101
to -505
.,.
DescriDtion
Establishes standards to
treat, store, or dispose
of hazardous wastes.
Establishes standards for
storage or treatment of
hazardous waste in piles.
Establishes standards for
disposal of hazardous wastes
in a landfill.
Establishes standards for
incinerators .
Point source discharges .
of wastewater require a
permit which establishes
standards for specific
parameters.
122
Applicable!
Relevant and
Appropriate
YES/-
NOIYES
YES/-
NO/NO
YES/-
YES/-
"
Septembft
I 1990
Comment
If waste is treated in I .,
substantive standards apply.
Temporary storage prior to
treatment is not subject to
standards.
The existing area of contamin-
ation will be closed as I land-
fill following treatment and. re-
depositing of the soil
(I 265.310).
Off-site treabnent of waste Is
planned.
Treated ground water dis-
charge limits will complf with
the COPDES permit limits or
be more stringent.
RE:O 12-C08OO1\maItin\rocltbU-1
-------
Standard, Requirement
Criteria. or Limitation
Regulation No.1
Regulation No.2
Regulation No.3
Regulation No.6
Regulation No.7
Regulation No.8
TABLE 9-1
MARTIN MARIE'ITA ASTRONAUI'ICS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUiREMi1.iH~
FEDERAL AND STATE
Citation
5 CCR 1001-3
5 CCR 1001-4
5 CCR 1001-5
5 CCR 1001-8
5 CCR 1001-9
5CCR 1001-10
. Description
Establishes emission control
regulations for particulates,
smokes, carbon monoxide,
sulfur oxides, and fugitive
particulate emissions.
Establishes odor emission
regulations.
Establishes permit require-
ments for construction or
modification of stationary
sources and regulations for
prevention of significant
deterioration.
Establishes new source per-
formance standards for 10-
cinerators, storage vessels
for petroleum liquids, sewage
treatment plants, new fuel-
burning equipment, and new
sources of sulfur dioxide.,
Regulations to control
emissions of volatile.
organic compounds.
Sets forth emission control
requirements for hazardous
air pollutants, including
beryllium, mercury and lead.
123
Applicable!
Relevant and
Appropriate
YES!-
YES!-
YES!-
YES!-
YES!-
YES!-
September 19, 1990
Comment
.
Thermal extraction of organics
will meet these standuds.
Air stripping and thermal ex-
traction employ source
emission.
VOCs are being treated on-
site.
These contaminants are
present on-site.
RE:Oll.cotOO1\mud8\roddJl.9-1
-------
Standard, Requirement
Criteria. or Limitation
Colorado Noise Abatement
Water Well and Pump
Water Well and Pump
Installation Contractors
Regulations
Well Peonit Regulation
TABLE 9-1
MARTIN MARIE'ITA ASTRONAUI'ICS GROUP SITE
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
FEDERAL AND STATE
Citation
Applicable/
Relevant and
Appropriate
Description
Establishes maximum
permissible noise levels
for particular time periods
and land use zone.
C.R.S. 112S-12-101
to -108
YES/-
C.R.S. fA 31-91-101
2 CCR 402-2
Establishes license require-
ments for well construction
and pump installation con-
tractors and minimum stan-
dards for well construction
and abandonment to protect
against pollution.
Establishes regulations for YES/-
construction and abandonment
of wells. .
YES/-
2 CCR 402-4
YES/-
124
c
September
1990
Comment
If the remedy causes noise.
Applies to recovery and moni-
toring wells for ground water.
Applies to recovery and moni-
tormg wells for ground water.
Applies to recovery and moni-
toring wells for ground water.
RE:012-01IOO2\martla\rocltbI.9-1
-------
September 19, 1990
re5trlctioDS.
LDRs are applicable to the remedy because the action requires treating waste listed in 40
CPR Part 261. The soil contains listed waste and will be treated in accordance with LDR standards
applicable to soil and debris. Presently, the remedy sets the treatment goal at the levels established
by EP A in the OSWER Directive: 9347.3-06FS may be used if during the design phase it is
determined necessary in order to implement this remedy. The hazardous waste storage standards are
not applicable to accumulation of waste prior to treatment, the remedy will meet relevant and
appropriate requirements to ensure protection of human health and the environment.
There are no action-specific ARARs addressing the stabilization process. ARARs pertaining
to air emissions and noise generation will be complied with. OSHA requirements will also be met.
9.2.2 Clean Water Ad (CW A) and Sare Drinking Water Ad (SDW A)
Discharges from the treatment of water from the Inactive Site or ground water contaminated
with RCRA hazardous waste, will meet limits established under the State and Federal Clean Water
Acts. Discharge limits for each chemical parameter are established in the COPDES permit.
Additionally, the discharge will be required to comply with water quality criteria for protection of
human health.
Ground water will be treated to meet chemical-specific standards specified by the Safe
Drinking Water Act (these being, MCLGs, MCLs) and a health-based concentration threshold for
NDMA and State Standards, whichever are more stringent. (Only MCLGs which are above zero are
relevant and appropriate.) .
9.2.3 Clean Air Ad (CAA)
Air emissions from the thermal extraction system, the air stripper for ground water and the
soil vapor extraction system wUl comply with requirements specified in Table 9-1. Spent carbon
from the granular activated carbon treatment of vapors will either be disposed of via incineration and
disposal (landfill) or regenerated at an off-site location.
COST-EFFECTIVENESS .
The selected remedy offers the best combination of effectiveness, implementability and cost
in comparison with the alternatives' evaluated. The remedy mitigates and minimi7e5 threatS to and is
protective of public health and the environment.
9.3
125
RE:012-C08OO1\manin\rod99-.end
-------
September 19, 1990
, Alternatives S-S and GW -4 provide a high degree of overall effectiveness based upon the
criteria of long-term effectiveness and permanence, reduction in toxicity, mobility and volume
through treatment of the cont.aminants on-site, ,and achievement of short-term effectiveness during
implementation.
,Compared with alternative S-4 which would be equally as effective, S-S is less cosdy.
Alternative S-S is nearly equivalent in cost to S-3 and provides better long-term effectiveness.
Alternative GW-4 provides the most extensive cleanup of ground water of any alternative and has
one of the shortest restoration timeframes. Alternative GW-3 is the only alternative with comparable
effectiveness; however, it does not address an area of highly CODt2minated bedrock ground water
which is addressed in GW-4.
9.4
USE OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO TIlE
MAXIMUM EXTENT PRACTICABLE
The selected remedy uses treatment and alternative technologies to the maximum extent
practicable to achieve a permanent solution which is cost-effective. The treatment processes
employed by this remedy will remove organic contamination from the soil up to an estimated 99 %
removal efficiency and immobilize the remaining contaminant.. 41 both inorganic (metals) and organic
with chemical and physical stabilizing processes. Removal and destruction of waste and the reduced
mobility of contaminants both from the soil and ground water will provide a permanent solution to
the maximum extent possible.
Although other alternatives would provide a protective remedy by reducing mobility of
contamin~nts, no other remedy was as cost-effective in providing permanence through reduction in
toxicity and volume of contaminants.
9.5
PREFERENCE FOR TREATMENT AS PRINCIPAL ELEMENT
As describe above, the selected remedy includes extensive treatment of both soil and ground
water to reduce the toxicitY" mobility and volume of con~minants at the site. The remedy includes
the use of thermal extraction for organic contaminants and cement-based stabilization for inorganic
contaminants in the Inactive Site soil. Chlorinated organic contaminal\ts (TCE and l,l,l-TCA) will
be removed and contained from the Chemical Storage Tank area using in-situ soil vapor extraction.
The ground water will be treated f9r VOCs, semi-volatiles and inorganic contaminants with a
specialized process using UV photolysis and oxidation to treat NDMA.
126
RE:Ol1-C08002\maniD\rod99-.ead
-------
September 19, 1990
.
. The remedy that satisfies the preference for treatment as a pri"ciple element by requiring the
treatment of each contAminant to the maximum extent practicable.
9.6
CONCLUSION
. The selected remedy will meet the statutory requirements as specified in Section 121 of
CERCLA by satisfying thetbreshold and balancing criteria for remedy selection as required by
section 300.430(e) of the NCP. The State of Colorado has also accepted this remedy and has
participated in its selection.
10.0 REFERENCES
CAl, 1990. Public Health Evaluation and Ecological Assessment, Martin Marietta Astronautics
Group, Waterton Facility, Revised. Clement Associates, Incorporated. Fairfax, Virginia.
March 29, 1990. -.
Eder, 1990. Final Feasibility Study, Martin Marietta Astronautics Group. Denver, Colorado. June
27, 1990.
EPA, 1987. Data Quality Objectives for Remedial Response Activities. U. S. Environmental
Protection Agency. EPAl54O/G-871003. March 1987.
EPA, 1990. National Oil and Hazardous Substance Pollution Contingency Plan. U. S.
Environmental Protection Agency. 40 CPR 300. Updated March 1990.
Geraghty & M'lller, Inc., 1987a. Results of Phase 1 Investigation, Martin Marietta Astronautics
Group. Denver, Colorado. June 10, 1987.
Geraghty & Miller, Inc., 1987b. Results of the Inactive Site Source Characterization Study and
Bench Scale Treatability Testing. Denver, Colorado. October 14, 1987.
Geraghty &. Miller, Inc., 1990. Final Remedial Investigation Report, Martin Marietta Astronautics
Group. Denver, Colorado. March 29, 1990.
Mackay, D.M., P.V. Roberts, and J.A. Cherry, 1985. Transport of Organic ContaminAnts in
. Ground Water. Environmental Science and Technology 19:364-392.
McDonald and Harbaugh, 1988. A Modular Three-Dimensional Finite-Difference Ground-Water
Flow Model, Techniques of Water-Resources Investigations of the United States Geological
Survey, Book 6, Chicago AI. .
SSPA, 1989. Modeled Estimates of Ground-water Cleanup Times for Martin Marietta, S.S.
Papadopulos and Associates, Inc. September I, 1989 (Revised September 8 and December 7,
1989). .
Trescott, P.C., and S.P. Larson, 1976. Documentation of Finite-Difference Model for Simulation of
Three-Dimensional Ground;Water Flow. U.S. Geological Survey Open-File Report 76-591.
August.
127
RE:012.c0a0ci2\maItiD\r0d99-.81111
-------
v
APPENDIX A
MARTIN MARlEITA ASTRONAUTICS GROUP SITE
RESPONSIVENESS SUMMARY
-------
September 19, 1990
APPENDIX A
Martin Marietta Astronautics Group Site
Responsiveness Summary
c
The community relations responsiveness summary for the site is divided into two sections;
1. a brief description of the site and the selected remedy, and 2. a summary of the oral and written
comments received during the public comment period concerning the Proposed Plan prepared by
EPA.
1.
Overview
The Martin Marietta Astronautics Group (MMAG) site is located in Jefferson County near
the mouth of Waterton Canyon on Highway 121 approximately 2S miles southwest of Denver. The
site occupies approximately 5200 acres and has operated since the 19505. Operations have included
the manufacturing of rockets for the U.S. Air Force and research and development associated with
aerospace equipment and fuels.
The facility is regulated under the Resource Conservation and Recovery Act (RCRA) as a
treatment, storage and disposal facility. During the operating period prior to RCRA, the waste
which could not be treated in the wastewater treatment plant on site was disposed of in five ponds
located on site. The area is now called the Inactive Site Ponds and is a major source of ground
water and soil contamination. There are several other sources of contamination on site which were
investigated during the remedial investigation or area being investigated under closure requirements
of the RCRA program.
The primary contaminants found at the site are volatile organic compounds (VOCS) including
tricbloroethene (TCE), 1,I,l-tricblorothane (TCA) and the degradation compounds from these
chemicals; semi-volatile chemicals including N-nitrosodimethylamine (NDMA) which is a chemical
associated with hydrazine fuels, and inorganic chemicals such as hexavalent chromium. The
cont~mination is highly concentrated in the Inactive Site area soil and ground water. Another area
with high levels of contamination in the ground water is the Manufacturing (M3) area. There are
low levels of contamination found off site in the Denver Water Department (DWD) Kassler propeny.
There is a separate site lo~ within the MMAG property which ~ federal facility and is on
the National Priorities List. The site is approximately 464 acres and is owned by the U.S. Air
A-I
RE:012-<:oaoo:\maniD\appen-l.rod
-------
September 19, 1990
Force. A separate program is in place to require the investigation of the site and select a remedy for
the remediation of the site.
On June 28, 1990 EPA proposed the preferred alternative for remediating the site. The
proposed remedy included Alternative S-S for the Inactive Site and Chemical Storage Tank areas and
Alternative GW -4 to address ground water. Both alternatives include extensive tteatment of
contJmin:ated media.
Alternative S-S requires that cont:amin:ated soils in the Inactive Site area be excavated and that
waste be separated for tteatment and disposal off site. The contaminated soil that remains on site
will be tteated by thermal extraction to remove organic chemicals and solidified to immobilize
inorganic contaminants. The treated soil will be returned to the area of cont:aminat10n and capped
with a multi-layered cap. Residues from the treatment process wi;! be.transported off site for
tteatment and disposal.
Alternative GW -4 for the ground water is a site-wide remedy addressing
coDt2minmon which originates from sources investigated during the remedial investigation and
hazardous waste management uoits subject to RCRA regulations.
. EP A solicited written and oral comment from the public during the comment period which
began on June 28, 1990 and closed August 27, 1990. Comments were received during the public
. meeting, held July 26, 1990, from the National Toxies Campaign (NTC) representative. Written
comments were submitted by MMAG.
2.
Public Comments and Response
Comment: First of all, we feel that it is important that no additional air emissions be factored into a
clean-up site, that we would be working as diligently as possible to red~ce air emissions in the
Denver metropolitan area. So that is something that is extremely important and needs to be
addressed.
EP A Response: EP A agrees with the concern over introducing additional sources of air emissions as
part of the remedy. After further consideration of the proposed alternative for ground water
involving .u stripping, EP A has d~ided to include emission ~ntrols as part of the final remedy for
this process. This decision is based upon several factors including the EP A policy (OSWER Dir.
93SS.0-28) applicable to areas of DOn-a1t:ainment for ambient air quality and the fact that MMAG is
A-2
.
RE:OI2-C08002\maniD\appc_.rod
-------
September 19, 1990
within an area of non-Attainment, and the requirement in the NCP to reduce the toxicity, mobility or
volume of contaminants through treatment. During the design phase, the specific type of control will
be determined.
i.J
Comment: We also call for independent monitorlDg. We feel that this is extremely important as
well, given the history of monitoring of different toxic contJllmination sites in Colorado.
EP A Re$ponse: As part of the regulatory responsibilities of EP A and the Colorado Department of
Health (CDH) the authority to enter facilities and collect samples and conduct inspections is provided
by law. However, neither EPA or CDH have the authority to require MMAG or any facility to
allow a third party which does not represent the agencies to enter a facility to collect samples.
Specifically, pursuant to the Hazardous and Solid Waste Am~ents (HSWA) Section 3007
and CERCLA Section 104(e), EPA is provided the authority to enter, inspect and collect samples
from facilities treating, storing or disposing of hazardous waste or facility, vessel, location with
hazardous substances. Part 3 of the Colorado Hazardous Waste Act (Section 25-15-301 (3»
authorizes CDH to enter and inspect hazardous waste facilities.
If any party desires samples from facility, then that party may contact the owner/operator of
that facility and request permission to obtain samples directly from that facility.
Comment: MMAG, believes that flexibility must be maintained throughout this cleanup process to
allow the work to proceed in an effective and economical manner. This will allow the procedure to
be updated as the knowledge of the site increases through time. A Record of Decision (ROD) that
allows for this 1cind 'of continual feedback will result in an accelerated achievement of our goals with
improved results.
EP A Re$J)Onse: EP A agrees that flexibility must be built into the ROD to allow for the development
of the most cost-effective design of the remedy specified in the ROD. However, the ROD must
specify the processes selected to remediate the CODtaminJllnt conditions at the site. The ROD will
retain flexibility accounting for the results of treatability studies which will be conducted during the
design phase. Soil treatment standards are specified with provisions for a variance. In addition, the
ROD acknowledges the potential difficulties with' achieving the cleanup goals for ground water as
specified' in the ROD and includes provisions to evaluate the response action and treatment standards
after a period of operation.
A:-3
RE:012-coaocn'-niD\appco-e.rod
-------
September 19, 1990
Comment: The Endangerment Assessment (EA) that evaluates the risk to human health and the
environment has used residential use scenario for the basis of evaluation. These requirements should
be reconsidered in light of Jefferson County's recent request to fUrther review zoning at the MMAG
and the county desires that -visually sensitive areas (hogback, mountain front) be protected as zoned
open' space. - These changes would reduce the health risk concerns, drinking water and showering
with water from ground water source, and therefore affect the final cleanup requirements as specified
in the Record of Decision.
EP A Resnonse: The use of the residential scenario in the EA was done to evaluate the reasonable
maximum exposure scenario for the site as required by EPA policy for conducting risk assessme~.
In doing so the EP A has a better understanding of the risk that may be posed to human health under
conditions of maximum exposure and be able to communicate that information to the public. The
fact that the zoning changes are being considered for the area does not_change need to assess what
EPA considers to be a potential reasonable maximum exposure scenario.
The ~ cleanup requirements specified in the ROD are based upon several requirements in
the NCP and CERCLA. Specifically, with respect to groUnd water remediation, EP A is to consider
restoring ground water to its beneficial use based 'upon previous uses and potential uses. The ground
water from the site was used as a drinking water supply and the potential for that demand in the
future exists. Furthermore, the EPA is to select remedies that attain permanent solutions through use
of treatment whenever practicable and remedies must attain applicable or relevant and appropriate
requirements (ARARs) or attain a waiver. Based upon these site Conditions and requirements, the
remedy selected is the most appropriate for the site and reconsideration of the standards set fonh in
the ROD based upon zoning which is subject to change would be inappropriate.
Comment: The soils alternatives evaluated in the presentation of the Proposed Plan did not consider
two of the alternatives set forth in the Feasibility Study (FS), limited action and in-situ stabilization.
The limited action alternative relies on isolating the property to prevent exposure while the in-situ
stabilization depends on adding materials to the soil that decreases the transport rate of cont~minllnts
while they decompose naturally. These alternatives do DOt appear to completely meet the
requirements for this cleanup but could compliment the other technologies. Again, they add to the
flexibility that we believe is needed in this ROD. .
EPA Re&ponse: The limited action alternative and the in-situ stabilization alternative are not
supported in the FS as beneficial over the comparable alternatives, no action and ex-situ stabilization,
respectively. The limited action alternative does DOt provide any significant increase in protection to
A-..
n...Ol1-C08C:102\manin'-PPe-.rocI
-------
September 19, 1990
u
. '
human health or the environment when compared to the DO action alternative. Most of the
components (e.g., restrictions) associated with the limited action are inherent with (or will be
incorporated into) the selected alternative during the design phase, thus addressing the Martin
Marietta comment that limited action could compliment the other technologies. The FS demonstrated
. .
that the in-situ stabilization process is inferior to the ex-situ stabilization process with respect to
effectiveness and implementability. The costs were near equivalent. As such, the EP A does not
believe that in-situ stabilization warrants any further consideration. It should be noted that the FS is
the meChanism used to reduce the range of alternatives to a manageable number of the most feasible
alternatives.
o
Comment: The request that the ROD remain flexible should be especially exercised in the soil vapor
extraction technology, suggested in all alternatives, for cleanup of soil cont.amin:.ltion at the chemical
storage tanks. The site compatibility for this removal method must be_evaluated before specifying
the technique. We suggest that a pilot test of the technology be incorporated.
EP A Re&ponse: EP A agrees that a pilot study should be conducted during the design phase to
determine the feasibility of in-situ soil vapor extraction. EPA, however, believes that in-situ soil
vapor extraction will work in this particular application and will specify in-situ soil vapor extraction
in the ROD. Should the process fail during the design phase, another process would be identified.
Comment: The on-site treatment and excavation called for in alternatives S-3 through s-s in the
proposed plan are based on handling the cover material, waste sludge, contaminated alluvium and
contaminated bacldill. The contaminated backfill, which was not included in the proposed plan,
should be combined with the cont.aminated alluvium and termed cont:.lmin:.lted soil to be compatible
with the FS repone
EP A ResDOnse: While it may not have been clearly stated in the Proposed Plan, references made to
contamin:.lted bacldill and/or contamin:.lted soil were intended to refer to both CODt:.lmin:.lted backfm
and alluvium that coqesponds to a volume of 24,400 cubic yards. This will be clearly stated in the
ROD and the term 8 cont.amin2ted soil8 will be used when referring to cont:.lmin2ted bacldi11 and
alluvium.
Comment: Based on the current information aviilable, the region where Pond If2 was located
appears to be uncontaminated. If additional data gathered during the design phase verifies this fact,
it seems unnecessary to remediate that area. This also seems like a reason to maintain flexibility in
A-S
RE:012.c08002\auiA\8ppc_.rod
-------
September 19, 1990
the discussion on the area that needs to be covered by the cap. The extent and nature of the cap
should be called out in the design report which will reflect the results of the additional study needed.
EP A Re$pOnse: During the design phase, additional. field sampling will be required to more
accurately determine the extent of contamination. From this information, the cap will be designed to
cover the CODt2min!lted area. A RCRA cap, however, will be specified in the ROD to the extent
shown in the FS which covers all five ponds. The extent of the cap may increase, decrease, or
remain the same dePending on the results of the field sampling program conducted during the design
phase.
')
Comment: Alternative S-S should state clearly that the collected volatile residue from the thermal
extraction process and the excavated waste must be treated and disposed of off-site while the
remainder of the material can be handled on-site. The ROD should clarify the target remedial action
level and target treatment level with the flexibility to accommodate the results of the design and pilot
results.
EP A Resnonse: The ROD will be written to clearly state that the waste and thermal extraction
residues will be treated and disposed of off-site and the rem2inder of the material can be treated and
disposed of on-site. Target remedial action levels and treatment levels will be presented in the ROD
and clarified as necessary to account for the analytical method detection limits and attainable
treatment technology levels.
Comment: The ground water treatment system described in alternative GW ~ should leave the nature
and order of the process step open so an economical design can be developed to best protect the
environment. This may leave the operations in the current MMAG wastewater treatment plant
available for final polishing.
~: EP A agrees with this comment, however, the process order presented in the
Proposed Plan was taken from the FS and will be used in the ROD for the purpose of presenting the
selected remedy. The design will dictate the order of the unit processes.
A-6
1lE...012-C08OO1\mmiD~.rocI
-------
u
()
APPENDIX B
MARTIN MARlETT A ASTRONAUTICS GROUP SITE
INACTIVE SITE PONDS
CROSS SECTIONS
September 19, 1990
-------
D
.
I
i!
GMI9
-GM190
814
-
Pond 4
K
-SCBII
~
;,
.
so
FCCI
.
100
.
I
c:
. f
."
Pond 5
SCB2
, SCB2J
IIAItTII IIAlllEnA AStllOHAU11CI OROUP
WAtUTOH. COLOIIADO
fiGURE 8-1 "
. INACTIVE SITE PONDS
CROSS SECTION LOCATIONS
OA TE CREATED: 5/14/80
-------
I
.
I
. i
o
!s
A
W
SCB49
Pond 1
SCBSO
A'
E
SCBSl .
Co
WA
10
All
--~R---_wC
. .
SCB49
Cr
TCE
TCA
Cis-DCE
.
I
I
2rt-Srt
S9S milk,
NO ul/kl
NO ul/k,
NO uJlkl
SCBSO
Cr
TCE
TCA
Cis-DCE
3rt-JUt
34 mJlk.
S30 uJlkl
1710 uJlk.
ND uJlkl
SCBSI
Cr
TeE
TCA
Cis-DCE
trt-3n
34 milk I
ND uJlkl
S7 ul/kg
ND uJl~1
Cros.o;.Section Key
Co . Cover Material
All . Alluvium
WA. Asphalt Rich Waste
WC . Cay Rich Waste
BR . Bcd Rock
IZJ . Interval Sampled
B . Infiltratlnl Sludge
Horizontal Scale
Vertical Scale
.1:300
.1:60
. Conlaminant Concentration Key
SCB49 . 5011 Borinlldentlfication
2rt-8rt. . Intervat Sampled
Cr '. . Total Chromium
TCE . Trlchiorocthene
TCA . I,t,t-Trlchloroethane
Cis-DCE . Cis-t,2-Dichloroethene
ND . Not Detected
f
IIAllTIt IWII£n A AStIIOIIAU1ICI GIOUP 1m
WAftJlTOtt, COLOtIADO
fiGURE 8..2 -
POND 1 ~
CROSS SECTIO~
DATE CREATED: 5/14/80
-------
! 10
, 20
.
J
i
I
,
.
8
W
Pond 1
SCB44
SCB4S
o
Co
Co
5
WA
WA
Co
WC
15
All
----------
BR --
SCB44
Cr
TCE
TCA
Cis-DCE
Sft-13ft
20 mg/kl
ND Ul/kl
3S1 ug/ka
647 ug/kl
SCB4S
Cr
TCE
TCA
Cis-DeE
Sft-ISft
95 ma/kl
646 ua/ka
ND ug/kl
S7 ug/kg
SCB46
Cr
TCE
TCA
Cis-DCE
SCB46
6fl-14(1
S ma/ka
ND ug/ka
ND ug/ka
ND ug/ka
SCB47
8'
E
SCBS4
Co
Co
WA
SCB47
Cr
TCE
TCA
Cis-DCE
IOrt-19ft
72 mg/kl
ND ug/kg
ND ug/kg
92 ug/kg
SCBS4
Cr
TCE
TCA
Cis-DCE
Cros.'i-Section Key.
co. Cover Materl.1
All . Alluvium
W A . Asphah Rich Waste
WC . a.y Rich Waste
BS . Black Siudae
BR . Bed Rocli
~ . Interval Sampled
I8J . Infilt~ating Siudae
Horizontal Scale
Vertical Scale
. 1:300
. 1:/jO
.'
9(t-l2(t
12 mg/kg
ND ug/kg
ND ug/kg
ND ug/kg
Contaminant Concentration Key
SCB44 . Soil Borinlldentlficatlon
Sft-l3ft . Interval Sampled
Cr . Total Chromium
TCE . Trichloroelhene
TCA . l,t,l-Trichloroethane
Cis-DeE. Cis-I,2-Dichloroethene
. ND . Not Detected
IIA.~ IWltUrA ASTIIOIfAUTICI GttOUP lITE
."'UTOH, COLOIIADO
FIGURE 8-3
POND 1
CROSS SECTION B-8'
DA TE CREATED: 5/14/80
-------
.
1
~
.
.
,
'\
,
,
\
,.
,
\
tlfl-19rl "
504 ml/kl
ND ug/kg \
ND ug/kg \
ND ug/kl
C
W
SCB42
o
5
10
15
120
u.
25
3D
35
Sc842
Cr
TeE
TeA
Os-DCE
40
Co
All
BR
SCB41
Cr ml/kl
TCE ualkl
TCA ualkl
Cis-DeE ullkl
SCB41
SCBS8
SCD\]
Co
Co
SCB13 0-4
/reel
Cr mi/kg, / 3.9
TCE ug/kl ND
TCA ug/kl ND
/,Cis-OCE ualkl ND
/'
SCB58 9rl-25rl
Cr /ND ms/kl
TCE/ 1590 ug/kg.
TCA NO uS/kg
/'Cis-DCE 321 ualkl
All
Pond 1
. SCBI2
Co
Co
flA
we
/
/'
/
12(1-16rl . / SCBO
NO malkl Cr
192000 u8lkl TCE
834 ualkg TCA
ND ullkl Cis-DCE
SCB12
Cr
TCE -
TCA
as-DeE
,;"
/'
20-24
reel
ND
206000
ND
51
()..4 4-8
reel reel
4.6 14
ND ND
ND - ND
ND 80
8-10 10-14 14-18 18.22 22-26. 26-30 30-34 34-39
reel reel reel reel reel reel reel reel
2310 191 191 1.1 2310 198 6.1 13.
12500 ND 102 ND ND 6120 ND 5160
ND ND ND ND ND ND ND ND
11400 1480 2380 1130 3800 2180 ND 'D
. \.
SCB43
SCD37
Co
All
---.--:----
--
--- BR
12rl-19rl
125 mg/k.
19600 ug/kl
ND ug/kg
11400 ug/k.s
SCB31
Cr
TCE
TCA
Cis-DCE
9rl-13(1
195 malkl
35400 ug/kg
1230 ug/kg
13800 ug/kg
~
"
C
E
Cross-Section Key
Co . Cover Malerial
All . Alluvium
WA . Asphall Rich Wasle
WC . Oay Rich Waste
BS . Black Sludge
Ln . Liner Malerial
BR . Bed Roc:k
~ . Interval Sampled
181 . hlfillralihg Sludge
Horizontal Scale
Vertical Scale
. 1:300
. 1:60
Conlaminanl ConcentratiQn Key.
SCB42 ... Soil Borina Identification
IUI-19rl . Inlerval Sampled
Cr . TOIII Chromium
TCE . Trichloroethene
TCA . 1.1.I-Trichloroethane
Cis-DCE . Cis-l.2-Dichloroethene
ND . Nol Delected
IW01N ..AlIEnA ASJIIOIfAIITtCI 01lOIII' 1111
WAtUTOII. COLOIIADO
RGURE 8-4
POND'
CROSS SECT~
OA TE CREATED: 5/14/.- /
:-C'
-------
.
J
i!
I
. .
120
o
5
10
15
25
3fI
35
.40
D
W
DI2
Pond 1
S~040
SCD3.S
SCDS9
SCDS
All
Co
\
\
\
\
\'
\
\
-\
\
\
\
\.
\
\
DR \
. \-
\
\
\
\
\
\
\
\
\
\
"-
,
,
8fl-25fl "
1080 milk. '
321000 ul/ke "
Nb ullke ,
126000 ullke ..... ,
.....
.....
.....
Co
/
I
/
/
I
/
/
I /
I WC /
./ /
" I /
, / /
, /
'/ /
/
/
---_/
WC
\
\ os
\_------
All
All
SCB40
Cr
TeE
TCA
CIs-DCE
20fl-22fl
10 ml/ka
ND ullka
ND ullka
5 I uB/lta
SCB59
Cr mllka
TCE ullka
TCA uB/ka
Cis-DCE ul/ita
20-26 37-4 I
feel feel
2790 II
995000 2790
ND ND
35000 ND
Co
SCB36
SCB36'
Cr
TCE
TCA
Cis-DCE
lorl-17fl
150 ma/kl
6020 uB/lta
ND ullita
5440 uB/ka
(.::
c;
D'
E
Cross-Section Key
Co . Cover MaieriAI
,..1 . Alluvium
WA . Asph~1t Rich Wale
WC . Oay Rich Wale
BS . Black Siudle
BR . Bed Rock
~ . Inlerval Sampled
Horizonlal Scale
Venlcal Scale
. 1:300
. 1:60
Contaminant Concenlration Key
SCB40 . Soli Borlna Idenlilicalion
aft-25fl . Interval Sampled
Cr . TOlal Chromium'
TCE ' . Trichloroelhene
TCA . l,l,l-Trichlnroelhane
Cis-DCE . Cis-I,2-Dichloroclhene
ND . NOI DeJected
IWrTIf IWIIEnA AStllClHAU1ICI GIICM' sm:
WAlDrON, COLCIIWIO
FIGURE 8-5
POND 1
CROSS SECTION D-D'
DATE CREATED: 5/14/80
-------
E
N
SCBS]
o
SCB52
Co
5
All
10
BR
IS
£
20 SCB53 6fl-9fl
Cr 21 mllkl
TCE tolD ualkl
TCA 111 ullkl
Cis-DCE tolD ullkl
SCBS2 .
Cr
TCE
TCA
Cis-DCE
3fl-Sfl
5.6 ml/ka
ND ullka
67 IIg/ka
ND lIg/ka
25
SCBSO
WC
SCBSO 3fl-l1h
Cr 34 mllka
TCE 530 ugfka
TCA 1710 ug/kS
Cls-DCE ND ug/ka
Coninminnnt Concentration Key
SCBS3 . Soil Borlnlldenllficalion
6(1.9fl . Inlerval Sampled
Cr - TOlal Chromium
TCE . Trichloroelhene
TCA . I,I,I-Trichloroelhane
Cis-DCE . Cis-I,2-Dichloroelhene
ND . NOI Delecled
)0-
3S
.
!
i
4o-J
I
I
Pond 1
SCD4S
SCD 15
Co
Co
WA
Co
01
WC
BR
All
SCB4S 5fl-18fl
Cr 95 milk,
TCE 646 ullk,
TCA NO ullka
CIs-DeE 57 ullkl
SCBI5
Cr
TCE
TCA
CIs-DeE
SCDS8
SCBS9
Co
Co
os
WC
WC
All
IOfl-14ft
19 mIlks
ND uS/kS
NO uS/kS
82 uS/k,
SCBS8
Cr
TCE
TCA
Cis-DCE
9fl-25fl
NO mg/ks
1590 uS/kS
tolD ug/kg
321 ug/kS
SCD59
Cr mslks
TCE uSlkS
TCA ug/kg
Cis.DCE uglkg
20.26 37-41
feel feel
2790 II
99S000 2790
ND ND.
35000 ND
.'
E'
S
SCB8
Co
Cross-Section Key
Co . Cover Mllerial
All . AlluvIum
W A . Asphalt RIch Wasle
WC .Oay Rich Waste
BS . Block Sludae
BR . Bed Rock
~ . Inlervai Sampled
B8I . Infillr.alR' Wasle '
Horlzonlal Scale
Venical Seale
-1:300
- 1:60
"
"
"
"
..
WC
--
-
-.
All
SCBB
Cr
TCE
TCA
Cis-DCE
. 2O(1-22fl
10 malk,
tolD ullk,
ND ualk,
51 ullkl
IWITII MAlll£n A AITIIOItAU1lC8 GIIOIIP lIT[
.ATUTON, COUIIIAIIO
FIGURE 8-'
POND 1 /
CROSS SECTIO E'
DA TE CREATED: 5/14/81.- - / /
-------
F
SW
! :TI~
10
.
I
~
f
i
I
WM
BR
SCB3S 2C1.SCt
Cr 44 milk.
TeE 2020 u<a
TCA ND us/ka
Cis-DeE ND us/k.
Pond 3
.0
N
SCBJS
SCBt4
o
is --"-
II.
SCB3S
Cr
io TeE
TCA
Cis-DeE
2fl-Sfl SCBI4
44 ma/k, Cr
2020 uJlltS TCE
ND uJlks TeA
ND uJllt, Cis-DeE
OfI-4fl
12 filS/it,
202 us/Its
ND us/Ita
ND us/Ita
SCB33
Cr
TeE
TCA
Cis-beE
Cross-Section Key
Co . Cover Malerlal
All . Alluvium
WM. Wasre Mil
BR . Bed Rock
~ . Inlerval Sampled.
0'
S
Horlzonlal Scale
Verllcal Scale
4fl-7fl
II ms/ks
9t20 us/ka
ND uS/kS
ND uS/ItS
. 1:300
. 1:60
Contaminant Concentration Key
SCB3S . Soil Borlns Idenllficallon
.2fl-Sfl . Inlerval Sampled
Cr . TOlal Chromium
TCE . . Tric:hloroelhene
TCA . I,I,I-Tric:hloroelhane
Cis-DeE. Cis-I.2.Dic:hloroelhene
ND . NOI DeleC:led
YMTllMAM:nA ASfllGHAU1ICI18OUP II1't
WAItIlTOH, COUIIWIO
FIGURE B-7
POND J
CROSS SECTION F-F' Ie O-G'
DATE CREATED: 5/14/10
-------
H
SW
SCB29 .
o
SCB4
5
ilo
\1.0
SCB29
15 Cr
TCE
TCA
Cis-DCE
20
I
.
I
~
I
s
11'1-41'1
8.3 mllitl
4640 ullkl
ND ualltl
ND ualltl
.'
,
'\
,
SCB]t
H'
NE
SCB9'
\ 1
\ Co . 1
\ ~.yW; - - 71 All
\ - - __I
\ 1
\ BS 1
\- __I
i
SCB4 6rl-10I'I SCD31
Cr 12 malltl Cr
TeE 90 ullitl TeE
TCA ND ui/itl TeA
~lT ND'~)'OCE
/
----
BR
. /
/
/ BR
/
/
3rl-IOrl
ND mg/kl
216 ug/kg
ND IIg/kg
ND ug/kg
Pond 4
I
SW
. SCB2S
SCB6
SCB27
o
Co
WC
BR
Ln All
i 10
Ii.
All
15 SCB25 ,3rt-51'1
Cr 502 mg/~
TeE ,16900 ug I
TCA ND ug/ltl
CIs-DCE ND ualltl
20
SCD6 ().4 4-8 SCD27 WI-Iart
reel reel Cr 5360 mal.,.
Cr mg/ka 506 265. TCE 280000 u Ita
TCE ug/lta 5450 39900 TCA ND ug/lta
TCA ullkl ND 23700 Cis-DCE ND ua/ka
Cis-DCE ualkl ND ND
I'
NE
GMt4
Cross-Section Key
Co . Cover Material
All . Alluvium
W A . Asphalt RIch Wute
WC . Oay Rich Waste
BS . Black Studio
Ln . Uner Material
DR . Bed Rock
. f2I . Interval Sampled
Horizonlal Scalo
Vertical Scale
. 1:300
.1:60
Contaminanl Concentration Key
SCD29 . Soil Borlnlldentlficatlon
1£1-4rl . Inlerval Sampled .
Cr .. TOlal Chromium
TCE . Tric:hloroethene
TCA . I,I,I-Trlc:hloroethane
CIs-DCE . Cis-I,2-Dlchloroethene
ND . Not ~tected
IWI,," MAlllEnA AS11tONAU11CI OIIOUP 1m
WATtIITOH. COLDItADO
FIGURE 8-8
POND 4
CROSS SECTION H
DATE CREATED: 1I/14/11t.
, I-I'
-------
.
, I
~
I
j
.
J
N
8
SCBJO'
SCB4 SCB28
5
1 10
II.,
,
,
,
,
,
1f1.1f1
1990 milk.
74000 u./q
ND ullk.
ND ullk. ,
SCB4 6(1.lorl
Cr 12 milk.
TCE 90 ullk.
TeA ND US/kS,
Cis.DCE ND u8lkS
All
15
SC830
Cr
TeE
TCA
Cis.DCE
20
SCB25
SCB7
All
SCB25
Cr
TCE
TeA
Cis-DCE
3fl-5fl
502 m8/k,
16900 ullkS
NO ullk.
~D ullkS.
SCB32
Cr
TCE
TCA'
CIs.DCE
SC028 ().4 4.8 8.12 12.16 16-20 21).2]
feet feet feet feet feel feet
Cr milks - 49 12 29 22 55 . 43
TeE ullk. 1050 3720 172 83300 1400000 6500000
TeA ullk. ND ND ND ND ND ND
as-DCE u..k, ND ND ND ND ND ND
Contaminant Concentration Key
SCBJO . 5011 Borin. Identincallnn
1f1-1ft . Interval Sampled
Cr . TOlal Chromium
TCE . Trichloroelhene
TCA . I,I,I-Trlchloroelhane
- Cis-DCE . CIs.I,2.Dichloloelhene
ND . Nol DeleCled
',All' BS
, \
'. \
"-
,
,
,
,
,
,
,
'-- - -
Po~d 4
J' K
S N
o
SCBJ2
5
110
II.,
15
. 20
OfI-3f1
18 milk,
470 uS/k,
ND uS/k,
ND ullk,
BR
SCD31
Cr
TeE
TCA
Cis-DCE
SCB)!
SCB)
SCB27
All
----
All
./
,/
./
./
/' BR
/'
./
./
Jrl.IOfI
ND milks
216 "Ilks
ND ullkS
ND uBlkS
SCJlJ
Cr
TCE
TeA
Os-DCE
8fl-l2ft SCB27
1090 mBlkS Cr
11200 uBlk, TeE
ND IIB/k. TCA
ND uBlk. rls-DCE
16fl.18fl
5J6O milk,
280000 ullk,
ND u8lk.
ND ullkS
K'
S
SCB24
Cross-Sealon Key
Co . Cover Mlterfa1
All . Alluvium
W A . Aspbalt IUcb Wale
WC . Cay Rlc:b Wale :
BS . Blact Sludao
IA . Uncr Materfa1
DR . Bed Rodt
121 . Interval Sampled
Horizontal Scalo
Venical Scale
. 1:300.
. 1:60
SCB24 1f1-5fl
Cr 448 milk,
TCE . 4480 ullk, "
TCA ND ullk. .
Cls-DCE ND uBlkS
IWnIt IlAlllt:nA AitIIOIIAU11CI OROUP snt
WA TtIlTCIN. COLOItADO
FIGURE 8-'
POND 4 .
CROSS SECTION J-,f . K-I(
DATE CREATED: 15/14/80
-------
,L
SW
SCBt
L'
Nt!
SCB21 SCB22
o
I' 5
. Pond 5
- 10
SCB21 0.2 2-4 4-6 6-8 8-10 10-"
leet leet leel leel leel leel
Crm~ 54 267 856 28900 38 38
TeBu I 706 2590 1100000 4700000 260000 330000
TCA uBlkI ND ND ND 163000 ND 130000
as-DeB ua/ka ND 161 ND ND ND ND
.
I
~
Contaminant Concentration Key
SCB2 . Soli Borlnlldentlficalion
. . Oft-Sit. Interval Sampled
Cr . Total Cuomlum
teE . Trlchtoroethene
TCA . J.J,I-Trlchtoroethane
Cis-DCE . Cis-t,2-Dichtoroethene
ND . Not Detected
I
M
N
SCB2
o
I'
SCB23
SCB21
M'
S
SCB20
DR
All
, 10
SCB2 Oft-Sit
Cr ' 98 mg/ltl
TeB 36600 us/kl
TCA 3690 u8lka
CIs-DeB ND uBlka
SCB21 0-2
leel
54
706
ND
ND
-----
Cross-Section Key,
Co . Cover Material
All . Alluvium
. we. Cay Rich Wate
BS . Dtack Sludge, '
DR . Bed Rock
f2I . Intervat Sampled
Horizontal Scale
Vertical Scale'
. 1:300
. 1:60
Cr m&Jkl -
TCE u&/ka
TCA u&Jkg
Os-DCE u&Jka
2-4 4-6 6-8 8.10 10-11
leel lee I 'Ieet leet leet
267 856 28900 38 38
2590 1100000 4700000 260000 330000
ND ND 163000 ND 130000
161 ND ND .ND ND
IIAIItIt IWftTTA U_AU11C8 ... It1t
."'EItJON. COLCIIIADO
FIGURE 8-10
POND 5
CROSS SECTION L-!
OA TE CREATED: 5/14/90
u-u'
------- |