United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R08-87/011
June 1987
&EPA
Superfund
Record of Decision:
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,
,I
TECHNICAL REPORT DATA
(PltfUe nfld /tttlfflctions on the ,evene IHfcwe completinl)
1. REPOAT NO. 12. 13. RECIPIENT'S ACCESSION NO.
EPA/ROD/R08-87/00l I
.. TITLE AND SU8TITLE 5. REPORT DATE
'SUPERFUND RECORD OF DECISION June 4. 1987
Rocky Mountain Arsenal, CO . e. PERFORMING ORGANIZATION CODE
First Remedial Action
7. AUTHORISI 8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM EL.EMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency Final ROD Report
401 M Street, S.W. I.. SPONSORING AGENCY CODE
washington, D.C. 20460 800/00
15. SUPPLEMENTARY NOTES
UI. ABSTRACT
The Rocky Mountain Arsenal (RMA) is a facility owned and operated by the United
States Department of the Army. It was established in 1942 with the primary mission of
manufacturing and assembling chemical and incendiary munitions to support the war
effort. .Afterwards, pesticides and herbicides were produced on-post by private leases.
Many of these substances, their by-products and residues we(e later disposed of
on-post. The RMA off-post site is located northeast of downtown Denver, Colorado,
adjacent to RMA. The area is nearly completely developed with residential subdivisions,
industrial facilities and gravel operations. South Adams County Water and Sanitation
District (SACWSD)' was created in 1953 to supply approximately 30,000 customers with well
water from the alluvium and bedrock. Recent studies by EPA and SACWSD indicate that
significant concentrations of organic solvents are present in the local and Regional
ground water system which is the main source of drinking water for SACWSD. This
operable unit addresses treatment or replacement of contaminated ground water within the
RMA off-post site prior to its use as drinking water by customers of the SACWSD. The
hazardous substances of primary concern present in the ground water supplying the SACWSD
wells include: trichloroethylene (TCE), tetrachloroethylene ( PCE),
l,l,l-trichloroethane, l,l-dichloroethane, l,l-dichloroethylene, and
trans-l,2-dichloroethylene. Other volatile, semi-volatile, and no'n-volatile organic
(See Attached Sheet)
17. KEY WORDS AND DOCUMENT ANALYSIS
~. DESCFlIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. CDSATI Field/Gtoup
Record of Decision
Rocky Mountain Arsenal, CO -
First Remedial Action
Contaminated Media: air, gw
Key contaminants: organics/VOCs, TCE, PCE,
l,l,l-trichloroethane, l,l-dichloroethane,
trans-l,2-dichloroethylene, vinyl chloride
18. DISTRIBUTION STATEMENT 19. SECURITY CL.ASS (T/lis Report/ 21. NO. OF PAGES
None 120
20. SECURITY CL.ASS (T/lis page) 22. PRICE
None
e,. ,- 2220-1 (R... 4-77)
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,
EPA/ROD/ROS-87/00l
Rocky Mountain Arsenal, CO
First Remedial Action
16.
ABSTRACT (continued)
compounds are present
of RMA off-post site,
date. Vinyl chloride
wells.
The remedial alternative selected for this site includes: construction
of a granular activated carbon (GAC) water treatment system with
regeneration of spent carbon at another loction; modification of the GAC
system, if necessary, to include an air stripping facility to treat vinyl
hloride; replacement of existing well pumps and motors; installation of
transmission piping; and, construction of laboratory and office space to
ensure that the remedy operates effectively. The estimated capital cost for
the GAC system is $S,869,000. If an air stripping facility is required, the
cost will be $10,100,000. The estimated annual O&M cost is $372,000.
in the ground water in areas adjacent to a upgradient
but have not been detected in SACQSD supply wells to
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~L PRO~t.c,
UNITED STATES ENVIRONMENTAL PROTECTION AG;;NCY
REGION VIII
999 18th STREET-SUITE 500
DENVER. COLORADO 80202.2405
ICfi _.t:~~ 1- ~':~') - f:( ~'L
PROJ: 7777-198 FILE~ DD
DOC:DATE: (:)6/(:)4/87 ENTRY DATE:
DOC CONT #: 198-RI1-DD-EDVL
::C1li:i
C. .:: ./ () E;" ,~:.;
DESC-ROD/1ST OP UNIT
RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
COMMUNITY RELATIONS RESPONSIVENESS SUMMARY
First Operable Unit
EPA's RHA Off-Post RIfFS Site
Commerce City, Colorado
June 4, 1987
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RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION FOR FIRST OPERABLE UNIT
SITE
EPA's RKA Off-Post RI/FS Site
Commerce City, Colorado
DOCUMENTS REVIEVED
I am basing my decision on the administrative record for the site,
including, but not limited to, the following documents describing the
analysis of the cost and effectiveness of the remedial alternatives for the
EPA's RKA Off-Post RI/FS site:
o Remedial Investigation for the First Operable Unit - EPA's RMA Off-
Post RI/FS Site, dated Dece~ber 1986 and prepared by Camp Dresser;
McKee (Includes Public Health Endangerment Assessment)
~
o Feasibility Study for the First Operable Unit - EPA's RKA Off-Post
. RI/FS Site, dated December 1986 and prepared by Camp Dresser &
McKee
o Preliminary Risk Assessment of the South Adams County Vater and
Sanitation District Vater Distribution System, dated April 17, 1986
and prepared by Clement Associates, Inc. for Camp Dresser & McKee
o Treatability/Feasibility Study for District Vater Quality
Improvement, dated May 1986 and prepared by James M. Montgomery
Consulting Engineers Inc. for South Adams County Vater and
Sanitation District
o Detailed Analysis for Organic Contaminant Removal, dated October
1986 and prepared by Black and Veatch for South Adams County Vater
and Sanitation District.
o Summary of Remedial Alternative Selection (attached hereto)
o Responsiveness Summary (attached hereto)
o Staff Summaries and B~iefing Documents
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~
DESCRIPTION OF SELECTED REHEDY
This operable unit addresses treatment or replacement of contaminated
ground vater vithin the EPA's RHA Off-Post RI/FS site prior to its use as
drinking vater by customers of the South Adams County Vater and Sanitation
District (SACVSD). The hazardous substances of primary concern that have
been released into the environment and are present in ground vater'
supplying the SACVSD veIls include trichloroethylene (TCE),
tetrachloroethylene (PCE), 1, 1, 1-trichloroethane, 1,1-dichloroethane,
1,1-dichloroethylene and trans-1,2-dichloroethylene. The contaminated
ground vater is the main source of drinking vater for SACVSD.
The selected remedy for the first operable unit of the EPA Off-Post RIIFS
site is the construction of a granular activated carbon (GAC) vater
treatment system and regeneration of spent carbon at another location. The
GAC system viII treat contaminated ~ater from the South Adams County Vate~'
and Sanitation District (SACVSD) drinking vater supply veIls prior to its
consumption as drinking vater. The GAC system viII attain a derree of
cleanup of the hazardous substances of primary concern vhich viII assure
protection of human health. Other volatile, semi-volatile, and non-
volatile organic compounds are present in the ground vater in areas
adjacent to and upgradient of EPA's RHA Off-Post RI/FS site, but have not
been detected in SACVSD supply veIls to date. In the event that other
volatile, semi-volatile, andlor non-volatile organic compounds are
identified in ground vater supplying the SACVSD veIls, the GAC system viII
have the greatest capability of the treatment alternatives evaluated to
treat a vide spectrum of such hazardous substances to a level that viII
assure protection of human health, vithout modification.
Vinyl chloride (a highly volatile polar compound) has.,lso been detected
upgradient from the SACVSD supply vells, although it has not been detected
in SACVSD supply vells to date. The GAC system may not treat vinyl
chloride to acceptable levels. The GAC system can be modified by the
addition of an air stripping facility to treat vinyl chloride in the event
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that vinyl chloride currently detected upgradient of the SACVSD supply
wells poses a threat to the SAcVSD supply wells and the public health. The
selected air stripping facility would be designed to treat vinyl chloride
to levels that assure protection of public health. EPA will continue to
monitor for vinyl chloride to determine whether it presents a threat to
public health.
Additionally, in order to ensure that the remedy operates effectively and
provides adequate safe drinking water supplies for the estimated SACVSD
water demand of 12.0 HGD, the remedy consists of the replacement of
existing well pumps and motors, the installation of transmission piping,
and the construction of laboratory and office space.
To assure protection of the public health in the interim period between
approval of the Record of Decision and completion of the selected permanent
GAC treatment system, the selected remedy provides for the continued ,
leasing and operation and demobilization of the temporary GAC treatment
system, installed in June, 1986 under EPA's removal authority, to treat
SACVSD drinking water until the permanent system is on line. The temporary
system is designed to treat contaminated ground water to levels at or below
Haximum Contaminant Levels (HCLs) established under the Safe Drinking Vater
Act (SDVA).
The remedy includes the fol~owing operation and maintenance activities:
o Periodic replacement of granular activated carbon and routine
equipment aaintenance and replacement;
o Provision of electrical power to run the facility;
o Provision of chemical additives to prevent scaling and bacterial
growth within the GAC contactors; and
o Personnel to operate ~he new facility.
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DECLARATIONS
Consistent vith the Comprehensive Environmental Response, Compensation and
Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and the National Contingency Plan, 40
CPR Part 300, I have determined that construction of a granular activated
carbon vater treatment facility to treat contaminated ground vater
underlying the EPA Off-Post RIIFS site is a cost-effective operable unit
remedial action, is protective of human health, and is consistent vith
possible future remedial actions. The selected remedy includes the
possible addition of an air stripping facility, as appropriate to assure
protection of human health, in the event that vinyl chloride currently
identified upgradient of the SACVSD veIls poses a threat to the SACVSD
veIls. The selected remedy also provides for the replacement of existing
.vell pumps and motors, the installation of transmission piping, and the
construction of laboratory and office space. Until the permanent GAC
system is on line, the selected remedy provides for continued leasing of
the temporary GAC system currently in place.
f
~
The selected remedy utilizes permanent solutions and treatment technologies
to the maximum extent practicable for contaminants identified to date in
SACVSD drinking vater supply veIls (GAC treatment vith incineration of
spent carbon at another location) for this operable unit. The selected
remedy for this operable unit viII reduce the volume and the toxicity and
mobility of contaminants identified in south Adams County drinking vater to
date through incineration of the volatile organic compounds adsorbed on the
,ranular activated carbon vhen the carbon is regenerated. Spent carbon
from the GAC treatment system viII be regenerated at an incinerator in
compliance vith Sections 3004 and 3005 of the Solid Vaste Disposal Act
(SVDA) and Section 121(d)(3) of CERCLA.
The applicable or relevant and" appropriate requirements for this operable
unit are the Maximum Contaminant Levels ("MCLs") established under the Safe
Drinking Vater Act ("SDVA") for hazardous substances, pollutants, or
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contaminants identified in south Adams County drinking water. Under the
SDVA, Congress established a two-pronged approach for determining
permissible levels of contaminants in water which is delivered to any user
of a public water system: (1) maximum contaminant level goals ("HCLGs")
are to be set at the level at which no known or anticipated adverse effects
on health of persons occur and which allows an adequate margin of safety;
and (2) HCLs are to be set as close to the HCLG as is feasible. Section
1412(b)(4) of the SDVA. HCLGs are non-enforceable health goals. HCLs are
enforceable requirements which specify the maximum permissible level of a
contaminant in water which is delivered to any user of a public water
system.
Section 1401(3) of the SDVA.
Congress defined the term feasible to mean:
... with the use of the best technology, treatment techniques, and
other means which the Administrator finds, after examination for
efficacy under field conditions and not under laboratory
conditions, are available (taking co~t into consideration) ....
Granular activated carbon is feasible for the control of synthetic
organic chemicals, and any technology, treatment technique, or
other means found to be the best available for the control of
synthetic organic chemicals must be at least as effective in
controlling synthetic organic chemicals as granular activated
carbon."
I
Section 1412(b)(5) of the SDVA.
The selected remedial action for this operable unit is a granular activated
carbon treatment system. In selecting GAC, EPA is utilizing a technology
which Congress explicitly recognized as feasible under the Safe Drinking
Vater Act. Id. Horeover, by specifying HCLs as the applicable or relevant
and appropriate requirement that cannot be exceeded for this operable unit,
EPA is implementing and acting consistently with the s~atutorily mandated
process and criteria that Congress prescribed for all public drinking water
systems nationwide. In addition, the HCLs selected as applicable or
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relevant and appropriate requirements for this operable unit for
contaminants identified in south Adams County drinking water assure
adequate protection of human health.
Por the above reasons, EPA has selected HCLs as the legally applicable or
relevant and appropriate requirement which the selected remedy must at
1
least attain for this operable unit.
Section 121(d)(2)(A) of CERCLA provides that remedial actions "require a
level or standard of control which at least attains (HCLGs) ... where such
goals ... are relevant and appropriate under the circumstances of the
release." This language, on its face, and Section 121 of CERCLA, taken as
a whole, gives EPA the discretion to determine, in light of the specific
facts at CERCLA sites, whether HCLGs are relevant and appropriate. It is
within the Agency's discretion to determine that HCLs are the applicable or
relevant and appropriate cleanup standards based on the circumstances ,
present at this site. For this particular operable unit, additional
factors are not present which suggest the need to attain HCLGS in order to
assure protection of human health. Therefore, the Agency has determined
that HCLGs are not relevant and appropriate under the circumstances of this
operable unit.
Specifically, the selected remedy shall at least attain, and shall in no
circumstances exceed, the following levels for hazardous substances,
pollutants or contaminants identified in south Adams County drinking water:
(1) proposed HCLs for volatile synthetic organic chemicals. See 50 Pede
leg. 46902 (Nov. 13, 1985); and (2) final HCLs. Table A sets forth EPA's
final and proposed HCLs. In the event that HCLs are revised, or amended to
include additional contaminants identified in south Adams County drinking
1. Applicable or relevant and appropriate requirements-are selected on a site-
specific basis. The selection of HCLs as the applicable or relevant and
appropriate requirement for this operable unit is not intended to establish
precedent for remedial action at other sites or operable units, including,
but not limited to, ground water and surface water restoration, and is not
intended to establish precedent for any contaminants not identified in south
Adams County drinking water.
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TABLE A
FINAL AND PROPOSED MCLs
PROPOSED MCLs FOR VOLATILE
SYNTHETIC ORGANIC CHEMICALSa
mg/l
Organic
Trichloroethylene (TCE)
Carbon Tetrachloride
Vinyl Chloride
1,2-Dichloroethane
1,1,1-Trichloroethane (TCA)
p-Dichlorobenzenec
Benzene
.1,1 Dichloroethylene
0.005
0.005
0.001
0.005
0.200
0.005
0.005
0.007
FINAL MCLs FOR ORGANIC b
AND INORGANIC CHEMICALS
mgll
Inorganic
Arsenic
Bari um
Cadmium
Chromium
Fluoride
Lead
Mercury
Nitrate (as N)
Selenium
Silver
0.05
1
0.010
0.05
4.0
0.05
0.002
10
0.01
O.O~.
Organic
Chlorinated hydrocarbons:
Endrin
Lindane
Methoxychlor
Toxaphene
mgll
0.0002
0.004
0.1
0.005
Chlorophenoxys:
2,4-D
2,4,5-TP Silvex
0.1
0.01
0.10
Total Trihalomethanes
: !!! 50 Fed. Reg. 46902 (Nov. 13, 1985).
See 40 CPR Part 141, Subpart B.
c See 52 Fed. Reg. 12878 (April 17, 1987).
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vater, the agency vill evaluate such revised or amended HCLs and amend the
Record of Decision, if appropriate, to require that the remedy attain the
revised or amended HCLs and assure adequate protection of human health.
. The Agency expects that the HCLs viII drive the design and operation of the
remedy. By not exceeding HCLs, the selected remedy vill assure protection
of human health for other hazardous substances, pollutants, or contaminants
identified in south Adams County drinking vater for vhich HCLs have not
been proposed or finally promulgated. In any event, the selected remedy
vill at least attain a level of control for such other hazardous
substances, pollutants, or contaminants that falls vi thin a total risk
range of 10-4 to 10-7 over a 70-year lifetime exposure, vith a goal of
attaining a level of control that reflects a 10-6 risk.
National Emission Standard for Hazardous Air Pollutants (NESBAPs),
. . .
established under the Clean Air Act,. for vinyl chloride and benzene, are
relevant and appropriate in the event that air stripping is required to
treat vinyl chloride (40 CPR Part 61, Subparts F and J).
,
Pretreatment standards promulgated pursuant to Section 307 of the Clean
Vater Act are applicable or relevant and appropriate in the event that the
selected remedy involves the discharge, indirect discharge, or introduction
of pollutants into a publicly owned treatment vorks from a source regulated
under sections 307(b), (c), or (d) of the Clean Vater Act. The remedy
currently does not contemplate such a discharge, indirect discharge or
introduction of pollutants.
This degree of cleanup vill assure protection of human health under this
operable unit. The selected remedial action is relevant and appropriate
under the circumstances of the release or threatened release of the
hazardous substances, pollutants, or contaminants of concern identified to
date in SACVSD drinking vater ~upply vells.
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The State of Colorado provided EPA with a list of applicable or relevant
and appropriate State standards, requirements, limitations, or criteria
("State requirements") for this operable unit on January 8, 1987. The
State amended its list on March 17, 1987 to delete several requirements and
add an additional requirement. EPA has reviewed the proposed State
requirements under the criteria set forth in Section 121(d) of CERCLA, and
determined that certain provisions within the following State requirements
generally are applicable or relevant and appropriate:
1.
The Colorado Hazardous Vaste Act and Regulations
Applicable to the extent the selected remedy involves the
generation, transportation, treatment, or storage of hazardous
waste in the spent granular activated carbon. The selected remedy
does not contemplate disposal of hazardous waste.
2.
The Colorado Primary Drinking Vater Regulations
Applicable or relevant and appropriate to the drinking water which'
vill be supplied to the public through the selected remedy, for
contaminants identified in the ground water which supplies the
SACVSD'suppiy wells.
3.
The Colorado Air Quality Control Regulations
Applicable or relevant and appropriate to fugitive particulate
emissions and emissions which may result from the selected remedy
if air stripping of vinyl chloride is required, or if storage or
transfer of volatile organics compounds is required.
4.
The Colorado Noise Abatement Statute
Applicable or relevant and appropriate to establish maximum
permissible noise levels for construction or operation of the
selected remedy.
s.
The Colorado Vildlife Statutes and Regulations
Applicable to the extent the selected remedy involves the taking,
possession, transportation, exportation, shipment, removal,
capture, or destruction of wildlife. The selected remedy does not
contemplate any of these activities.
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6.
The Vater VeIl and Pump Installation Contractor Act and Regulations
Applicable or relevant and appropriate to pump installation. The
selected remedy does not contemplate the construction of vater
veIls.
7.
Historical, Prehistorical, and Archaeological Resources Act
Applicable or relevant and appropriate if the selected remedy
involves the investigation, excavation, gathering or removal from
the natural state of any historical, prehistorical, and
archaeological resources vi thin the state. The selected remedy
does not contemplate any of these activities.
8.
The Colorado Vater Quality Control Act and. Regulations
Applicable or relevant and appropriate to the extent the selected
remedy involves the discharge of pollutants to vaters of the State
of Colorado. The selected remedy does not contemplate such a
discharge.
A detailed evaluation of the State requirements is set forth in Appendix B.
. .
The selected remedy viII at least attain the legally applicable or relevant'
and appropriate State requirements identified in Appendix B.
The State of Colorado and the SACVSD have been consulted and concur with
the s~lected remedy (Appendix C). The action will require future operation
and maintenance activities to assure the continued effectiveness of the
remedy.
The Agency for Toxic Substances and Disease Registry (ATSDR) reviewed the
Remedial Investigation and Feasibility Study reports, including the Public
Health Evaluations, and stated the opinion that "any of the proposed
remedial alternatives for treatment of the South Adams County Vater and
Sanitation District (SACVSD) ground water will achieve the necessary
treatment required to protect public health." ATSDR's concurrence is
included in the Administrative Record.
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Pursuant to an Agreement entered into between the Army and EPA on September
26, 1986, the selected response action for this operable unit will be
partially financed by the U.S. Army. The selected remedy is a cost-
effective response measure necessary to abate, minimize, stabilize,
mitigate, or eliminate the threat posed to public health by TCE in south
Adams County drinking water. To the extent that Army or other PRP funds
are used for the design, construction and implementation of the response
action, the State cost share requirements under Section 104(c)(3) of CERCLA
shall not apply. The State cost share requirements under Section 104(c)(3)
shall apply to any Pund-financed construction and implementation of the
selected remedial action.
The EPA will continue its comprehensive remedial investigation/feasibility
studies for the entire EPA aHA Off-Post RI/PS site, and expects to complete
. such studies by about Spring of 1988. The feasibility study will evaluate
whether or not further response actions are necessary at the EPA aHA
Off-Post site to protect human health and the environment. Following
completion of the FS, a Record of Decision will be prepared addressing
future response actions, if any. The selected remedy for this operable
unit is consistent with a permanent remedy.
,
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Section
SUMMARY OF REMEDIAL ALTERNATIVES SELECTION
TABLE OF CONTENTS
Site Location and Description .......................................
Site History
Current Site
[[[ .
Enforcement Analysis ................................................
S ta tus .................................................
Alternatives Evaluation .............................................
Cos t [[[
Institutional Considerations ........................................
Technical Feasibility ...............................................
Public Health, Velfare, and Environmental Impacts ...................
Permanency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communi ty Re1a t ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consistency with Other Environmental. Requirements ...................
Recommended Al t erna t 1 ves .............................................
Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . ; . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . .
Pu t ure . Ac t lons ..... '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX A -
APPENDIX B
APPENDIX C -
APPENDIX D -
Responsiveness Summary
- Applicable, Relevant, and Appropriate State
Requirements, Limitations, and Criteria for
RI/FS Site First Operable Unit'
State and SACVSD Concurrence Vith Remedy
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Table
1
2
3
4
5
6
7
8
Figure
1
LIST OF TABLES
Frequently Reported Chemicals Detected in Recent
CLP-Validated Analytical Results for Ground Vater
Monitoring Vells in the Off-Post Study Area ..............
Other Detected Organic Compounds
............. .............
Recent Analytical Results for SACVSD Municipal Vells
......
Total Potential Excess Cancer Risks Associated with
Ingestion and Inhalation Exposure Routes - SACVSD
Hun! ci pal Vells ...........................................
Cos t Summary Table........................................
Vater Treatment Alternatives ..............................
Selected Alternative - Capital Costs
..................... .
Selected Alternative - Operation and Maintenance Costs and
Equipment Replacem~nt Costs ~...........................~..
LIST OF FIGURES
EPA Study Area.............................................
Page
6
8
10
13
22
24
34
36 ,
Page
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
EPA'S RMA OFF-POST RIfFS SITE
SITE LOCATION AND DESCRIPTION
The Rocky Mountain Arsenal (RHA) was proposed for inclusion on the National
Priorities List (NPL) in October, 1984. RMA is a facility owned and
operated by the United States Department of the Army. RHA was established
in 1942 with the primary mission of manufacturing and assembling chemical
and incendiary munitions to support the war effort. Subsequently,
pesticides and herbicides were produced on-post by private leasees. Many
of these substances, their by-products and residues were disposed on-post.
The Army is conducting RIfFS studies on-post and off-post north of 80th
Avenue.
EPA's RHA Off-Post RIfFS site is located about 10 miles northeast of the
downtown area of Denver, Colorado and adjacent to RMA. The site extends
westward from the. Rocky Mountain Arsenal to the South Platte River. The
southern boundary is formed by 56th Avenue and Sand Creek, and the northern
boundary by 80th Avenue from the Arsenal to the South Platte (Figure 1).
The site encompasses a large part of the municipality of Commerce City and
a portion of unincorporated Adams County. The area is nearly comple~cly
developed with residential subdivisions, industrial facilities and gravel
operations.
, .
The South Adams County Vater and Sanitation District (SACVSD) supplies
approximately 30,000 customers with water from wells completed in alluvium
and bedrock within the study area. Recent studies completed by the EPA and
SACVSD in the study area indicate that significant concentrations (100
parts per billion range) of organic solvents are present in the local and
regional ground water system. Private wells and SACVSD wells located
within the study area are cont~minated by organic solvents. Two of these
.organic compounds--trichloroethylene - TCE and 1,1-dichloroethylene--were
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reported in concentrations in wells in excess of maximum contaminant limits
established under the Safe Drinking Vater Act. To date, organic solvent
contamination appears to be limited to the alluvial aquifer.
. SITE HISTORY
The municipality of Commerce City and adjacent areas grew in response to
the rapid post-war proliferation of industry north and east of the City of
Denver. In order to provide a water supply and sewage treatment to the
residents and businesses, a special governmental district was created in
1953: The South Adams County Vater and Sanitation District (SACVSD). The
SACVSD supplies its approximately 30,000 customers (1986) with water from
wells completed in alluvium and bedrock.
Until recently, hundreds of private supply wells were in use throughout the
south Adams County area. Almost all.of the private wells tapped the
alluvial aquif~r.. Host of these private wells were taken out of service i~
summer 1986 when -residences were connected to the public water supply.
system as part of an Emergency Removal Action conducted by EPA. EPA Field
Investigation Team (FIT) data showed that water from these wells exceeded
Safe Drinking Vater Act criteria for volatile organic compounds and posed a
threat to public health.
,
.
/
Contaminated ground water containing organic solvent compounds has been
detected by various government bodies, including EPA, sporadically since
1981 throughout the EPA Off-Post RIfFS site in both individual and SACVSD
supply wells. The Rocky Mountain Arsenal, a proposed site on the National
Priorities List (NPL), has been identified as one of two or more sources of
the contamination. To date, EPA has not identified positively other
sources of the contamination, but surrounding potentia~ sources include two
other CERCLA sites (Sand Creek and Voodbury) which are listed on the NPL
and are directly to the south and southwest of EPA's Off-Post RIfFS site,
local industries within south Adams County and upgradient of the supply
wells, or a combination of any of these sources. Hany of these operations
-------
require the use of degreasing solvents, including TCE and other chlorinated
hydrocarbons. Additional data must be gathered to determine the nature and
extent of contamination from individual sources, and relative contributions
from such sources.
On Harch 20, 1986, the Army signed an Agreement with EPA under which the
Army agreed to transfer to EPA $1,000,000 for use by the EPA in selecting,
designing and implementing response measures necessary to abate, minimize,
stabilize, mitigate or eliminate the threat or potential threat posed to
the public health or welfare by the presence of TCE in south Adams County
drinking vater. EPA is using the Army money pursuant to its Agreement with
the Army to pay for the leasing of granular activated carbon filters for
the temporary treatment of well vater at SACVSD veIl sites located at 77th
and Quebec, 77th and Pontiac, and 64th and Quebec. The treatment system
commenced operation in Hay 1986. The current leased system is a temporary
treatment method. The leased equipment will have to be replaced with a
permanent system. The current system is leased, is sized to treat only a .
porii~n of the current maximum day flow of 12 HGD, and is not cost
effective over a 30-year plant operation period.
I
In addition to addressing the public vater supply system through
in~tallation of the temporary system, EPA connected private wells in areas
of south Adams County with contaminated ground water to the SACVSD public
system pursuant to EPA's removal authority.
During the course of the Remedial Investigation, EPA determined, in
accordance with 40 CFR 300.68(c), that an operable unit should be conducted
to address replacement or treatment of contaminated ground water prior to
its use as drinking water to assure continued protection of the public
health. The operable unit approach is cost effective and consistent vith
the final remedy.
This operable unit addresses treatment or replacement of contaminated
ground water within the EPA Off-Post RI/FS site prior to its use as
-------
drinking water by customers of the SACYSD. EPA is currently planning field
studies for subsequent operable units which will address response actions
necessary to protect human health and the environment. These response
actions may include aquifer restoration and source control measures.
CURRENT SITE STATUS
Ground water sampling results collected from the various areas of
investigation through August 1986, indicate the presence of large areas of
contaminated ground water within the EPA RIfFS off-post study area
boundaries. Contamination levels are highest in the area east of Holly
Street. Volatile organic compounds are present in the highest
concentrations and are most widespread throughout the sampled area. Six,
volatile organic compounds are detected consistently in ground water
samples. These compounds are 1,1-dichloroethane (DCA), 1,1-dichloroethene
(DCE), trans 1,2-dichloroethane (Trans-DCE), 1,1,1-trichloroethane (TCA),
.
trichloroethylene (TCE) and tetrachloroethene (PCE). Yhile these compounds
each vary in levels of concentration and extent, they are all found in
detectable concentrations between Holly and Quebec Streets in the study
area and between 56th and 80th avenues. Samples collected from the SACYSD
municipal wells in this zone also show detectable contamination from
volatile organic compounds. The recent highest measured concentrations of
VOCs within the study area as shown in Table 1.
,
Other compounds detected in areas potentially 'upgradient of the SAC
alluvial production wells include benzene, vinyl chloride, pesticides, and
other non-volatile organic compounds. Several upgradient potential source
areas both on and off the Arsenal have yet to be characterized. These
potential sources are being studied by EPA and the Army.
Concentration plots of these six VOCs, based on recent ground water
sampling data, are provided as. ,Figures 5~24 through 5-29 of the Remedial
-------
TABLE 1
ROCKY. MOUNTAIN ARSENAL
EPA OFF-POST RI/FS SITE
FREQUENTLY REPORTED CHEMICALS DETECTED IN RECENT
CLP-VALIDATED ANALYTICAL RESULTS FOR GROUND VATER
MONITORING VELLS IN THE OFF-POST STUDY AREA
Chemical
Maximum Reported
Concentration
March - July 1986
(ug/li ter)
Standard/
Advisory
(ug/li ter)
1,1-Dichloroethane
1,1-Dichloroethylene
trans-1,2-Dichloroethylene
1, 1, 1-Trichloroethane
Trichloroethylene
Tetrachloroethylene
14a
11
16
58
120
21
4000:
7
70e
200b
5b
0.7c
a This value is an estimated
not met. Highest reported
b MCL or proposed MCL.
c No promulgated or proposed MCL, the6efore, the reference concentration
for potential carcinogens (at a 10- risk level) is shown.
quantity because quality control criteria were'
.
unqualified value is 6 ug/llter.
d There is no MCL or reference concentration developed to date for
potential carcinogens. Therefore, an EPA Health Effects Assessment
for lifetime exposure is shown.
level
e
There is no MCL or reference concentration developed to date for
potential carcinogens. Therefore, an EPA Health Advisory level for
lifetime exposure is shown.
SOURCE: Report of Groundwater Analyses--Adams County Vells (CDM 1986
a,b,e). '
-------
Investigation. The presence of other identified volatile
organic compounds and pesticides is shown on Figures 5-30
the Remedial Investigation.
and non-volatile
through 5-34 of
Table 2 shows a reference list of all other compounds tentatively
identified to date in private wells within the Off-Post RIfFS study area.
Sampling data for the SACVSD supply wells for the period November 1985 to
Hay 1986, is listed in Table 3. Two of the compounds, DCE and TCE, exceed
the Federal SDVA HCLs for presence of VOCs in drinking water.
Higher concentrations than those shown in Table 1 for a number of organic
solvents, have been identified in areas adjacent to and upgradient of the
current study area. Honitoring for ground water contaminants is
continuing.
. .
People may be exposed to volatile organic contaminants present in water
~
while using the water for drinking, bathing, cooking, cleaning, irrigation,
and other routine domestic activities. Exposure may be through ingestion,
inhalation, or dermal contact. A preliminary evaluation (Clement
Associates, Inc. April 17, 1986) indicated that the potential incremental
health risks associated with direct ingestion of water and inhalation of
volatilized contaminants while showering are reasonably quantifiable and
outweigh the risks associated with other potential exposure pathways.
Additionally, estimation of potential exposure by direct ingestion of water
and inhalation during showering would provide a reasonable
order-of-magnitude estimate of risk from exposure by all routes.
Therefore, only exposure by these two pathways was considered in the
endangerment assessment for this operable unit (Remedial Investigation
Report, Section 6.0).
I
Carcinogenicity potency factors were used to estimate the potential excess
cancer risks associated with e~posure to the contaminants of concern listed
in Table 1.
-------
TABLE 2
OTHER DETECTED TENTATIVELY IDENTIFIED ORGANIC COHPOUNDS
a Compound CAS ..
Abbreviation
HECL methylene chloride 75-09-2
ACET acetone 67-64-1
CCL4 carbon tetrachloride. 56-23-5
TOL toluene 108-88-3
VYCL vinyl chloride 75-01-4
CLRF chloroform 67-66-3
2DCA 1,2 DCA 107-06-2
DIHP DIHP DIHP
XYL total xylenes 1330-20-7
ETHB ethyl benzene 100-41-4
CLB chlorobenzene 108-90-7
DCP 1,2 dichloropropane 78-87-5
2TCA 1,1,2 TCA 79-00-5
HXYL m-xylene 1
OXYL o,p-xylene ?
BUT 2-butanone 78-93-3 I
FLOR flourene 86-73-7
PHL phenol 108-95-2
PNAN phenanthrene 85-01-8
PHTH phthalate 7
BBPH butylbenzylphthalate 85-68-7
DEPH diethyl phthalate 84-66-2
DBPH di-N-butylphthalate 84-74-2
NAP napthalene 91-20-13
HNAP 2-methylnaphthalene 91-57-6
DPHL 2,4 dimethylphenol 106-44-5
HETH 1-hexanol 2-ethyl 104-76-7
DFRN dibenzofuran 132-64-9
BPH bis(2 ethylhexyl)phthalate 117-81-7
ANIL aniline 62-53-3
CNAP chloronaphthalene 91-58-7
2DCB 1,2 dichlorobenzene 95-50-1
3DCS 1,3 dichlorobenzene 541-73-1
4DCB 1,4 dichlorobenzene 106-46-7
DBCP DBCP 96-12-18
-------
TABLE 2 (cont.)
OTHER DETECTED TENTATIVELY IDENTIFIED ORGANIC COMPOUNDS
Abbreviationa
Compound
CAS I
DIAZ
ABHC
DDT
24D
TP
DDD
HPEP
ALDN
ISDN
ENDN
DLDN
DDE
EDSF .
ETPR
diazinon
alpha-BHC
4,4 DOT
2,4-D
2,4,5-TP
4,4 DDD
heptachlor epoxide
aldrin
isodrin
endrin
dieldrin
4,4 DDE
endosulfan II
ethylparathion
333-41-5
319-84-6
50-29-3
94-75-7
93-72-1
72-54-8
1024-57-3
309-00-2
?
72-20-8
60-57-1
72-55-9
33213-65-9
56-38-2
a Abbreviation code used on Figures 5-24 through 5-34 of the Remedial
Investigation Report.
,
.
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TABLE 3
ROCKY MOUNTAIN ARSENAL
EPA OFF-POST RI/FS SITE
RECENT ANALYTICAL RESULTS FOR SACVSD MUNICIPAL YELLS
(ul/li ter)
SampUnr Da te
Nov. Dec. Jan. Feb. Mar. May
Chemical 85 85 86 86 86 86
Vell No.1
Methylene chloride NS NS NS 4b NS NS
Vell No.2
1,1-Dichloroethane 6 4 (18 (1 (1 NS
1, 1, 1-trichloroethane 7 5 6 3 3 NS
Trichloroethylene 19 31 40 29 36 NS
Tetrachloroethylene 11 7 5 3t (1 NS ,
Methylene chloride (1 9 (1 (1 NS
Vell No.3
1,1,1-Trichloroethane 5 4 6 3 4 NS
Trichloroethylene 46 39 40 40 47 NS
Trans -1,2-Dichloroethylene 3 (2 (2 (2 (2 NS
Methylene chloride (1 9 (1 <1 (1 NS
Tetrachloroethylene 8 5 4 5 5 NS
Vell No.5
Trichloroethylene 11 6 7 7 7 NS
Tetrachloroethylene 4 3 . <1 3 (1 NS
Bromoform 14 <1 <1 <~ <1 NS
Methylene chloride (1 7 (1 3 (1 NS
1, 1, 1-Trichloroethane (1 <1 <1 1 <1 NS
Vell No. 12
Trichloroethylene NS NS NS 3 NS NS
Yell No. 14
Trichloroethylene 8 NS NS NS NS NS
Tetrachloroethylene 2 NS NS NS NS NS
-------
TABLE 3
RECENT ANALYTICAL' RESULTS FOR SACVSD MUNICIPAL VELLS
(ul/liter) (Continued)
Sampling Date
Nov. Dec. Jan. Feb. Mar. May
Chemical 85 85 86 86 86 86
Vell No. 15
Methylene chloride NS 5 <1a 4b <1 NS
1,1,1-Trichloroethane NS <1 <1 1 2 NS
1,1-Dichloroethane NS <1 (1 2 (1 NS
Trans 1,3-Dichloropropene NS <1 <1 2 (1 NS
Vell No. 16
1,1,1-Trichloroethane 5 NS 4 5 5 NS
Trichloroethylene 15 NS 13 14 11 NS
Tetrachloroethylene 8 NS 5 5 (1 NS ,
Chloroform (1 NS 2 (~ (1 NS
Methylene chloride (1 NS <1 4 <1 NS
1,1-Dichloroethane (1 NS (1 4 6 NS
Vell No. 17
1, 1, 1-Trichloroethane 4 3 5 3 5 3
Trichloroethylene 10 8 8 9 9 12
Tetrachloroethylene 1 (1 (1 (! (1 2
Methylene chloride (1 4 (1 3 (1 4
1,1-Dichloroethylene (1 (1 (1 (1 (1 2
Vell No. 18
1,1,1-Trichloroethane 1 (1 3 <1 <1 NS
Tetrachloroethylene 1 (1 <1 <1 <1 NS
1,1,2,2-Tetrachloroethane 2 <1 <1 <1 <1 NS
Methylene chloride <1 11 <1 <1 <1 NS
Trichloroethylene <1 2 2 <1 <1 NS
Toluene <1 2 <1 <1 <1 NS
NS . Not 88mpled
a Concentrations are belov the approximate aethod/sample detection limit
listed.
b Methylene chloride vas als.o fo\tnd in the laboratory blank at 4 ug/li ter.
SOURCE: HRS Vater Consultants, Inc. Summary data and Cenref Labs
Laboratory Reports.
-------
The use of SACVSD water during two exposure periods was considered in the
public health endangerment assessment: (1) the 1- to 2-year period needed
to complete the RIfFS and follow-up activities for the SACVSD"system1, and
(2) lifetime period. The total excess cancer risks associated with
exposure by ingestion and inhalation to 1,I-dichloroethylene,
tetrachloroethylene, and trichloroethylene in water from SACVSD wells are
shown in Table 4. The risks associated with 2-year exposure at the minimum
and mean concentrations considered by eit~er ingestion or inhalation, and
the total risk for concurrent exposure by both routes are less than 10-6.
At maximum exposure concentrations, the risks for 2-year exposure by either
ingestion or inhalation or for concurrent exposure by both routes equal or
exceed 10-6. The additive excess cancer risks associated with lifetime
exposure to contaminants in ~ACVSD wells by ingestion and inhalation ranges
from 10-6 to 10-4 for the three exposure levels considered.
The pathway of concern for this operable unit is that 'which is transporting'
.
the contaminants from sources to the receptors. The principal migration
pathway for organic contaminants is the ground water within the alluvial
aquifer that underlies the site. This aquifer is the primary drinking
water source for approximately 30,000 area residents via several SACVSD
municipal wells. A significant plume of organic contamination has been
documented to extend up to 4 miles upgradient from the municipal wells in
the area of 77th and Ouebec.
ENFORCEMENT ANALYSIS
On March 20, 1986, EPA entered into an Agreement with the United States
Department of the Army for the purpose of transferring $1 million from the
Army to EPA for use in the selection, design, and implementation of
treatment systems or other cost-effective response mea~ures necessary to
abate, minimize, stabilize, mitigate, or eliminate the threat or potential
1. EPA installed a temporary treatment system in May 1986 which is providing
safe drinking water at levels below the SDVA MCLs.
-------
TABLE 4
ROCKY MOUNTAIN ARSENAL
EPA OFF-POST RI/FS SITE
TOTAL POTENTIAL EXCESS CANCER RISKS ASSOCIATED VITH
INGESTION AND INHALATION EXPOSURE ROUTES--SACVSD
MUNICIPAL VELLSa
Total Risk
Additive Cancer Risk Additive Cancer Risk
for 2-Year Exposure for Lifetiae Exposure
6X10-; Minimum Exposure 2XIO-~
5xlO- lxlO-
6xlO-B 2xlO-6
3xlO-7 Mean Exposure lxlO-;
2xlO-B 8xlO-
3xlO-7 lxlO-5 ,
~
2x]O-: Maximum Exposure lx10-4
lxlO- 3xlO-5
3xlO-6 lxlO-4
Route of Exposure
Ingestion
Inhalation
Total Risk
Ingestion
Inhalation
Total Risk
Ingestion
Inhalation
a Total excess cancer risks vere obtained by summing the risks associated
vith ingestion and inhalation exposure to l,l-dichloroethylene,
trichloroethylene, and tetrachloroethylene, respectively.
Trichloroethylene and tetrachloroethylene are classified in EPA's
veight-of-evidence for carcinogenicity Group 82, aeaning they are
considered probable human carcinogens. 1,I-Dichloroethylene is
classified in Group C, aeaning it is considered a possible human
carcinogen. Exposure to 1,1-dichloroethy1ene is only considered under
the aaximua exposure concentration Icenario.
-------
..
threat posed to the public .health or welfare by the presence of TCE
contamination in south Adams County drinking water. The Agreement states
that the Army was one of two or more sources or potential sources of TCE
contamination of drinking water supplies in South Adams County and provided
for EPA reimbursement of the Army in the event that EPA determines that
sources other than the Army are responsible for TCE contamination and
liability may be approximately and reasonably apportioned to these other
sources. The Agreement also provided that EPA may enter into cooperative
agreements pursuant to section 104(d) of CERCLA with the State of Colorado
or political subdivisions thereof to perform the work called for under the
Agreement.
On April 4'0 1986, EPA authorized the leasing and installation of a
temporary GAC treatment system pursuant to its removal authority. EPA
entered into a cooperative agreement on April 7, 1986 in the amount of
$500,000 with the SACVSD and the State of Colorado for the leasing,
installation, and operation of mobile GAC filters. The Cooper,tive
Agreement was amended on May 19, 1986 to provide an additional $500,000.
Army funds transferred to EPA under the March 20, 1986 Cooperative
Agreement were used to fund the removal action under the Cooperative
Agreement.
,
On September 28, 1986, the Army provided EPA with an additional $6 million
pursuant to an amendment to the March 20, 1986, Agreement for the same
purposes as provided for under the March 20, Agreement. To date, other
responsible parties for the TCE and other hazardous substance contamination
of the south Adams County drinking water supply have not been positively
identified. In the event such parties are identified, EPA may seek to
recover its response costs from such parties pursuant to section 107 of
CERCLA and to require the PRPs to undertake any additi~nal response action
at the site to the extent provided for by CERCLA, RCRA, or other relevant
authority. EPA may also seek °additional.funding .from the Army.
-------
ALTERNATIVES EVALUATION
The FS evaluated alternatives suitable to abate the threat posed by
hazardous substances, pollutants, or contaminants in SACVSD drinking water.
Individuals exposed over a lifetime to the highest levels of contamination
in the ground water through ingestion or inhalation have an excess risk of
cancer of 1x10-4 to 2x10-6. The remedial alternatives evaluated for this
operable unit have the objective of minimizing or eliminating exposure to
the contaminants present in the contaminated ground water used as a
drinking water source by the SACVSD in order to assure protection of public
health. Future operable units will address source control measures, and/or
cleanup of the ground water.
In accordance with Section 300.68(f) of the NCP, EPA developed the
following categories:
Category
. Description
,
1.
Alternatives for treatment or disposal at. an off-site
facility.
2.
Alternatives which attain applicable or relevant and
appropriate public health or environmental standards.
3.
Alternatives which exceed appJicable or relevant and
appropriate public health or environmental standards.
4.
Alternatives which do not attain applicable or relevant and
appropriate public health or environmental standards but will
reduce the likelihood of present or future threat from the
hazardous substances and which provide significant protection
to public health, welfare, and the environment. This must
include an alternative which most closely approaches the
level of protection provided by the applicable or relevant
standards.
5.
No action alternative.
-------
.
The alternatives screened are:
Category
Alternative
No Action
5
1.
2.
Alternate Vater Supply
2,3
3.
Air Stripping of Volatile Organic Compounds
2,3
4.
Air Stripping of Potential Semi-Volatile Organic Compounds
Air Stripping of Volatile Organic Compounds with
Off-Gas Treatment
2,3
2,3
5.
6.
Air Stripping of Potential Semi-Volatile Organic Compounds
with Off-Gas Treatment
2,3
7.
Granular Activated Carbon (GAC)
2,3
8.
Air Stripping with Off-Gas Treatment for VeIls 14 and 16.
GAC for wells 2, 3, 5, 15, and 17
2,3 ,
2,3
9.
Continued Use of GAC System Leased for Removal Action
10. Blending
4
In addition, alternatives 5-9 provide a range of treatment alternatives
vhich permanently and significantly, in vhole or in part, reduce the
toxicity, volume or mobility of the hazardous substances, pollutants or
contaminants identified in SACVSD drinking water supply wells to date.
The RIIFS for this operable unit vas initiated on October 2, 1985, prior to
the enactment of SARA. In accordance with current EPA policy at the time
of commencement of the RI/PS, the Region considered Haximum Contaminant
Levels (HCLs) established under the Safe Drinking Vater Act (SDVA) as the
applicable or relevant and appropriate requirements ("ARARs") for this
operable unit. See "CERCLA Compliance with Other En~ironmental Statutes,"
50 Fed. Reg. 47946, 47949 (N~v. 29, 1985) (HCLs included in list of
. potential ARARs; HCLGs (formerly RHCLs) included in list of other
requirements to be considered).
-------
EPA developed alternatives to attain or exceed HCLs, the ARARs for this
operable unit before SARA. The table above reflects this approach, i.e.,
alternatives that attain or exceed ARARs are alternatives that attain or
exceed HCLs.
All of the alternatives, with the exception of blending and
no action will attain or exceed HCLs.
After the enactment of SARA, EPA identified a range of ARARs for public
comment in the FS, which included HCLs, HCLGs, and water quality criteria.
See Consistency with Other Environmental Requirements, pp. 26. EPA has
determined that the applicable or relevant and appropriate requirements for
this operable unit are the Haximum Contaminant Levels ("HCLs") established
under the Safe Drinking Vater Act ("SDVA") for hazardous substances,
pollutants, or contaminants identified in south Adams County drinking
water. Under the SDVA, Congress established a two-pronged approach for
determining permissible levels of contaminants in water which is delivered
to any user of a public water system: (1) maximum contaminant level goals'
.
("HCLGs") are to be set at the level at which no known or anticipated
adverse effects on health of persons occur and which allows an adequate
margin of safety; and (2) HCts are to be set as close to the HCLG as is
feasible. Section 1412(b)(4) of the SDVA. HCLGs are non-enforceable
health goals. HCLs are enforceable requirements which specify the maximum
permissible level of a contaminant in water which is delivered to any user
of a public water system. Section 1401(3) of the SDVA.
Congress defined the term feasible to mean:
... with the use of the best technology, treatment techniques, and
other means which the Administrator finds, after examination for
efficacy under field conditions and not under laboratory
conditions, are available (taking cost into consideration) ...
Granular activated carbon is feasible for the control of synthetic
organic chemicals, and any technology, treatment technique, or
other means found to be the best available for the control of
synthetic organic chemicals must be at least as effective in
controlling synthetic organic chemicals as granular activated
carbon."
-------
Section 1412(b)(5) of the SDVA.
The selected remedial action for this operable unit is a granular activated
carbon treatment system. In selecting GAC, EPA is utilizing a technology
which Congress explicitly recognized as feasible under the Safe Drinking
Vater Act. Id. Horeover, by specifying HCLs as the applicable or relevant
and appropriate requirement that cannot be exceeded for this operable unit,
BPA is implementing and acting consistently with the statutorily aandated
process and criteria that Congress prescribed for all public drinking water
systems nationwide. In addition, the HCLs selected as applicable or
relevant and appropriate requirements for this operable unit for
contaminants identified in south Adams County drinking water assure
adequate protection of human health.
Por the above reasons, EPA has selected HCLs as the legally applicable or
. relevant and appropriate requirement which the selected remedy must at
least attain for this operable unit:2
,
Section 121(d)(2)(A) of CERCLA provides that remedial actions "require a
level or standard of control which at least attains (HCLGs) ... where such
goals ... are relevant and appropriate under the circumstances of the
release." This language, on its face, and Section 121 of CERCLA, taken as
a whole, gives EPA the discretion to determine, in light of the specific
facts at CERCLA sites, whether HCLGs are relevant and appropriate. It is
within the Agency's discretion to determine that HCLs are the applicable or
relevant and appropriate cleanup standards based on the circumstances
present at this site. For this particular operable unit, additional
factors are not present which suggest the need to attain HCLGs in order to
2. Applicable or relevant and appropriate requirements are selected on a site-
specific basis. The selection of HCLs as the applicaule or relevant and
appropriate requirement for this operable unit is not intended to establish
precedent for remedial action. at other sites or operable units, including,
but not limited to, ground water and surface water restoration, and is not
intended to establish precedent for any contaminants not identified in south
Adams County drinking water.
-------
assure protection of human health. Therefore, the Agency has determined
that HCLGs are not relevant and appropriate under the circumstances of this
operable unit.
Specifically, the selected remedy shall at lea~t attain, and shall in no
circumstances exceed, the folloving levels for hazardous substances,
pollutants or contaminants identified in south Adams County drinking vater:
(1) proposed HCLs for volatile synthetic organic chemicals. !!! 50 Pede
Reg. 46902 (Nov. 13, 1985); and (2) final HCLs. Table A sets forth EPA's
final and proposed HCLs. In the event that HCLs are revised, or amended to
include additional contaminants identified in south Adams County drinking
vater, the agency viII evaluate such revised or amended HCLs and amend the
Record of Decision, if appropriate, to require that the remedy attain the
revised or amended HCLs and assure adequate protection of human health.
I
The Agency expects that the HCLs viII drive the design and operation of the"
remedy. By not ~xceeding HCLs, the selected remedy vill assure protection.
of human health for" other hazardous substances, pollutants, or contaminants
identified in south Adams County drinking vater for vhich HCLs have not
been proposed or finally promulgated. In any event, the selected remedy
vill at least attain a level of control for such other hazardous
substances, pollutants, or contaminants that falls vi thin a total risk
-4 -7
range of 10 to 10 over a 70-year lifetime exposure, vith a goal of
attaining a level of control that reflects a 10-6 risk.
Since shipment of contaminated soils or drinking vater is not vi thin the
objective of this operable unit, development of an alternative for off-site
treatment or disposal (40 CPR Section 300.68(f)(1)(i» is not appropriate.
However, spent carbon from the GAC system vill only be transferred to a
facility operating in compliance with sections 3004 and 3005 of the Solid
Vaste Disposal Act (SVDA), in accordance with section 121(d)(3) of CERCLA.
. "
A discussion of ARARs for this operable unit follows in the section of this
document titled "Consistency Vith Other Environmental Requirements."
-------
Alternatives vere subjected to an initial screening to narrov the list of
potential remedial actions for further detailed analysis using the criteria
of cost, effectiveness, and acceptable engineering practices as directed by
40 CPR Section 300.68(g). Costs including Operation and Haintenance (O&H)
vere considered for each alternative. Each,alternative vas screened by
evaluating feasibility, applicability, and reliability. Effectiveness in
protecting human health vas considered.
During the screening process, the No Action alternative vas eliminated
based on effectiveness because it does not protect human health.
Inhabitants vould continue to remain exposed at risk levels above 10-6, due
to VOC concentrations in drinking vater.
Alternative No.9 for using the leased GAC units vas eliminated during the
'screening process based on effectiveness, acceptable engineering practices,
and cost because the units are under~iied (excessive head loss through the~',
filters vill not,allov the District to meet peak demands), are nat cost
effective for a 30-year plant life and the manufacturer's statement that
the units are not for sale. The alternate vater supply alternative and the
alternative of air stripping of potential semi-volatile organics vith
off-gas treatment vere eliminated based on cost criteria. The costs of
these tvo alternatives far exceed the capital and O&H costs of other
alternatives evaluated and do not provide substantially greater public
health protection.
The blending alternative vas eliminated based on effectiveness. TCE
concentrations are too high in individual veIls to produce blended vater
that vould have TCE concentrations belov the SDVA HCLs.
The remaining alternatives vere evaluated in more detail in accordance with
40 CPR Section 300.68(h). Each alternative vas evaluated for cost,
effectiveness in achieving the. desired human health protection,
implementability of the alternatives, permanency resulting in a permanent
-------
and significant decrease in the toxicity, mobility and volume of the
hazardous substance, institutional considerations, and adverse impacts.
COST
Table 5 contains the estimated present value costs of each of the remaining
alternatives. Three alternatives (granular activated carbon, air stripping
vith off-gas treatment, and air stripping vith off-gas treatment for tvo
veIls and GAC for five vells) vere comparable at all three discount rates.
The other tvo air stripping alternatives vere eliminated because they do
not meet the preference under Section 121 of SARA for remedies vhich
permanently and significantly reduce the mobility, toxicity, and volume of
volatile organic compounds.
. INSTITUTIONAL CONSIDERATIONS
I
Future use of g~ound vater from nev private veIls that vould drav vater
from the alluvium underlying the study area is not expected to meet the
ARAR criteria. Therefore, the EPA may consider seeking institutional
controls that vould restrict future use of alluvial ground vater underlying
the EPA Off-Post RIIFS study area for drinking vater as a part of the
second operable unit. As previously noted, existing private veIls vere
connected to the SACVSD system by EPA in Summer 1986.
TECHNICAL FEASIBILITY
Enrineering, implementation, reliability and constructability vere
evaluated. The treatment technologies are all based on proven technologies
and all have. history of acceptable use. All treatment alternatives
reduce the concentration of volatile organic compounds to less than the
levels that EPA has determined to be applicable Federal and State.
requirements (see page 17).
-------
RKA_Hisc/3rd Draft ROD/32
T1JlLE 5
COST SlMtARy TABLE
Alternative
Discount Rat. 1\1
Capitd
Granular
Activated Carbon
S
8 3/8
10
$8,869,000
Air Strippinq of
VOCs
$3,659,700
5
8 3/8
10
- Air Strippinq of
Se.i-VOCs
5
8 3/8
10
$7,105,500
Air Strippinq of VOCs
With Off-Gas .
Treat_nt
5
8 3/8
10
$5,409,400
I
N
N
I
Air Strippinq Wells
No. 1~, 16, GAC Wells
No.2, 3, 5, 15 , 17
5
8 3/8
10
$7,238.100
1$7, 738,~00Ie
Annual 0'"
Cost Estiaates Dollars
Annualized
Equipaent Replace8ent
604,100
496,400
2,084,900
896,000
567,900
1687,0001.
28,600
40,500
46,600
26,300
)7,200
42 , 900
89,200
126,200
145,400
52,300
74,000
85,200
H,700
44,900
51,700
Pres.nt WOrth at
Disc~unt Rate 1$1.0001
5\a 8 3/Ub 10,c,d
18 ,593 16,024 15,005
11,694 9,460 8,744
40,521 31,140 ~8,137
19,985 15,953 14,662
16,454 13,899 13,081
118,785,. 115,6941e 114,7041e
a
b
c
d
Present WOrth of Annuity ractor 1]0 yrl = 15.37
Present WOrth of Annuity ractor 1]0 yrl = 10.87
Pr.sent worth of Annuity ractor 1]0 yrl = 9.43
Use of 10\ Discount Rat. Recoaaended by EPA Iref.
With Off-qas Treataent
.
No. 311
-------
In accordance with Section 300.68(h)(2)(v) of the NCP, an analysis was made
of waste minimization, reuse, and destruction. Under the recommended
alternative, the VOCs will be destroyed by incineration when the carbon is
regenerated.
, PUBLIC HEALTH AND ENVIRONMENTAL IHPACTS
The RIIFS included an assessment of the extent to which each alternative
would effectively prevent, mitigate, or minimize threats to, and provide
protection of public health and an analysis of adverse environmental
impacts. These are summarized in Table 6. The second operable unit vill
address whether or not future response actions are necessary to protect
public health, welfare, and the environment.
PERMANENCY
,
.
All the vater treatment alternatives evaluated reduce the concentrations of
volatile'organic compounds in drinking water to less than the levels that
EPA has determined to be applicable Federal and State requirements (see
page 17). The GAC and air stripping with off-gas treatment alternatives
provide a permanent treatment solution by either-incinerating at an
approved RCRA facility or recoyering the VOCs. The air stripping without
off-gas treatment alternatives transfer the VOCs from the water to air.
(These are summarized in Table 6).
COHMUNITY RELATIONS
The Community Relations Responsiveness Summary (attached) describes the
community's nature and level of concern, and the responses and concerns
regarding the alternatives evaluated in the FS.
-------
TABU' WM'D TP.£Ar.tEHr AL~TIV.U roa I.A On'-I'OST RII1"S SIn
Co_itV
Co.t 1$1,OOOt Public Dlvir_ntd ae.pon.e
Altamativa Capitd .n.ant Worth Hedeh Concern. eonc:emsa- Technical Concam. Concern. b Othars
hl'88nency -
" . 3/" 10\
1. G~aaula~ Activated ','" 11,"3 1I.0Z. 15,005 .educes public If conU.inant LeN VOC'. ara COIlpAUbla
Ca~bon bad th threat to levals incraasa re.istanca incinuat8cl and with Ion., ran.,e
18.. than the dCJftificantlv, d8strov8cl du~iRCJ ~e..,1iation
AIIARs. carbon replacaaent re.,eneraUon ot ot araa
costs ..~ be bi9h. GAoC
.olu collpOWMb ~ld .
not be re80v8cl.
Z. Ai~ Stdppin., - VOC'. 3,660 11,". ',." ',77. .educes public VenUn., ot ~.tura ot cont..- Itodenta VOI;'. ara C"lIpAtible
bedth threat to VOC'. to .tha inant. ..V cbaDia. ~e.i.tanca transte~~ed t~08 with Ion., ran.,e
Ie.. than the at80sphaia tIon-volatUe dua to vate~ to air ~e...uation
AlARs. Potantial contributes to contaainants ..V ventin., VOC'. ot araa
worke~ e.posu~a. 08- tOI'88Uon nndar strippa~ to at80.pba~a
ineffective and
~aquire addiUonal
aquip88nt.
3. Ai~ st~ippin., - 1,106 .0,521 ]1.140 2',131 .educes Public Vantin., of. Systa8 ..y be Itodarata
Seai-VOC'. health threat to VOC'. to the overdasiCJfted to~ ~eshtanca . VOC's are Coapatible
la.. than tha at80spbera or9anics that..v due to V8DtiRCJ tran.te~r8cl t~08 with Ion., ran')e
I ARARs. PotenUd cont~ibuta. to never be pre.ent VOC'. to vater to air re..dhtion
N worker e.posu~a. 080na tOI'88t1on in the wate~. at80spbe~a ot area
~ Non-volatUa
I contaainant. ..V
~enda~ st~ipp8~
ineftective and
~aqui~e additional
aquip88nt.
.. Ai~ Stdppin9 ot VOC'. 5,.0". It,tl5 15.153 It,66Z .educe. public Hi9h ..int_a LeN to , .. .
With otf-Ga. T~eataent baalth thraat to to~ dispo.al of Itodanta VOC'. a~e COIlpAUbla
la.. than the .olvent.. ~eai.tanca ~8Covar8cl and with 10n9 ran.,e
ARARs . Non-volatUa indnarat8cl o~ ~e...uation
cont_inant. ..V ~acycl8cl ot area
~8Rd8~ .trippa~
ineffectiva and
~aqui~e additional
aquis-ant.
..
-------
TUU; 6 -TEll ft£AfttEIII' AL'l'DNATIVES rw EPA 0Fr-1'OS'I' RlIPS sm: Icant.1
..
Alt.maU...
Capital
Co8t 1$1,0001
h...nt North
I'ubUc
"alth Concerns
10\
Envir_nt8l
Coac8£ns.
Tec:hnical Cone.me
C:-ity
".pon..
Conc.m.
..rean.nc}' -
Oth...
I
N
.VI
I
5. Air Strippin9 ..11. It
. 16 GAC ..11. l, J,
5, 15 . 11
Sa. Air Strippin9 ..ith
Off~. Tr.at88Dt
..u. 14 . 16. . (lAC
_II. l, J, 5, 15 . 11
"
1 JII'
1841c.. public
b..lt" thr..t t.o
1... than the
AMb. Pot.nUd
MOrk.r .spo.ur..
1841c.. public
he. 1 th threat to
1... than the
AMb.
VentlD9 of
.\IOC'. to th.
at.,.pIIe..
cont ribut.. to
0.- for-hon
'lbr- .eparat.
fadliti.. are
required.
_-volat.il.
contaainent. -y
r.nder stripper
in.tract i v. end
requi.. additional
equip88Dt. GAC
doe. not r-v.
polar c~unda.
'lbr- .epar.t.
f.dUh.. are
required.
_vol.til.
conta.inent. ..y
render .tripper
in.trecth'. end
.equl'. .dditlonal
equip88nt. GAC
do.. not C880V8
polar coapounds.
Low to \IOC'. ar.
8Dd8r.t. tran.f.rr.d f.08
r..i.tance vat.r to 81r
due to watiIUJ
\IOC'. to
.t....ph.r.
Low
r.d.tent.
VOC'. ar.
inc:in.rat.d or
recovered and
recycled
Co"... ti b 1.
..ith Ion., ..nq.
r...di..t lon
of area
Co..,.tibh
..ith Ion., '8n.,.
r._diatlon
0' ar..
1,nl
n,199
U,OI1
. Each .It.rnatlY. .v.luated addr..... only the public vat.r .upply.
b aquif... 'Iha.. .tudi.. ar. in proqr....
S.ctlon Ill, of the Supe.fund A88nd88Dt. end "authori.ation Act of 1916.
16,.5.
1,111
11,115
It ,104
15,'94
Subsequent operabl. unit. ..ill add.... cl.anup of the contaaineted 9round ..at.r supply
..
-------
CONSISTENCY VITB OTHER ENVIRONMENTAL REQUIREMENTS
On October 17, 1986, the President signed the Superfund Amendments and
Reauthorization Act of 1986 (SARA). Section 121(d)(1) of SARA requires
that selected remedial actions attain a degree of cleanup of hazardous
substances released into the environment and of control of further release
at a minimum which assures protection of human health and the environment.
Section 121(d)(2) of SARA states that remedial actions shall require a
level or standard of control which at least attains legally applicable or
relevant and appropriate standards, limitations, criteria, and requirements
("requirements") of Federal environmental laws, and applicable or relevant
and appropriate promulgated requirements under State environmental or
siting laws that are more stringent than federal requirements.
The Feasibility Study for this operable unit identified a range of I
potential ARARs~, including MCLs, MCLGs, water quality criteria established'
under the Clean -Yater Act, NESBAPs for vinyl chloride and National Ambient
Air Quality Standards (NAAQS). After consideration of public comments, the
Agency has determined that the applicable or relevant and appropriate
requirements for this operable unit are the Maximum Contaminant Levels
("MCLs") established under the Safe Drinking Yater Act ("SDYA") for
hazardous substances, pollutants, or contaminants identified in south Adams
County drinking water. Under the SDYA, Congress established a two-pronged
approach for determining permissible levels of contaminants in water which
is delivered to any user of a public water system: (1) maximum contaminant
level ,oals ("HCLGs") are to be set at the level at which no known or
3. The RIIFS for the site was commenced prior to the enactment of SARA. At
the commencement of the RIIFS, the Agency had identified Maximum
Contaminant Levels (MCLs) established under the Safe-Drinking Yater
Act as the ARARs for the sit~ in accordance with current Agency policy.
The Region identified a range,of ARARs for public comment in the FS, which
. included MCLs, MCLGs, and water quality criteria. All alternatives evaluated
in the FS, with the exception of the no action and blending alternatives,
would reduce the concentration of volatile organic compounds to less than
the levels that EPA has determined to be applicable Federal and State
requirements (see page 17).
-------
.
anticipated adverse effects on health of persons occur and which allows an
adequate margin of safety; and (2) HCLs are to be set as close to the HCLG
as is feasible. Section 1412(b)(4) of the SDVA. HCLGs are non-enforceable
health goals. HCLs are enforceable requirements which specify the maximum
permissible level of a contaminant in water which is delivered to any user
of a public water system. Section 1401(3) of the SDVA.
Congress defined the term feasible to mean:
... with the use of the best technology, treatment techniques, and
other means which the Administrator finds, after examination for
efficacy under field conditions and not under laboratory
conditions, are available (taking cost into consideration) ...
Granular activated carbon is feasible for the control of synthetic
organic chemicals, and any technology, treatment technique, or
other means found to be the best available for the control of
synthetic organic chemicals must be at least as effective in
controlling synthetic organic c~emicals as granular activated
carbon."
,
Section 1412(b)(S) of the SDVA.
The selected remedial action for this operable unit is a granular activated
carbon treatment system. In selecting GAC, EPA is utilizing a technology
which Congress explicitly recognized as feasible under the Safe Drinking
Vater Act. Id. Horeover, by specifying HCLs as the applicable or relevant
and appropriate requirement that cannot be exceeded for this operable unit,
EPA is implementing and acting consistently with the statutorily mandated
process and criteria that Congress prescribed for all public drinking water
systems nationwide. In addition, the HCLs selected as applicable or
relevant and appropriate requirements for this operable unit for
contaminants identified in south Adams County drinking water assure
adequate protection of human health.
-------
.
For the above reasons, EPA has selected HCLs as the legally applicable or
relevant and appropriate requirement which the selected remedy must at
least attain for this operable unit.4
Section 121(d)(2)(A) of CERCLA provides that remedial actions "require a
level or standard of control which at least attains (HCLGs) ... where such
,oals ... are relevant and appropriate under the circumstances of the
release." This language, on its face, and Section 121 of CERCLA, taken as
a whole, gives EPA the discretion to determine, in light of the specific
facts at CERCLA sites, whether HCLGs are relevant and appropriate. It is
within the Agency's discretion to determine that HCLs are the applicable or
relevant and appropriate cleanup standards based on the circumstances
present at this site. For this particular operable unit, additional
factors are not present which suggest the need to attain HCLGs in order to
assure protection of human health. Therefore, the Agency has determined
that HCLGs are not relevant and app~opriate under the circumstances of this'
.
operable unit.
Specifically, the selected remedy shall at least attain, and shall in no
circumstances exceed, the following levels for hazardous substances,
pollutants or contaminants identified in south Adams County drinking water:
(1) proposed HCLs for volatile.synthetic organic chemicals. See 50 Fed~
Reg. 46902 (Nov. 13, 1985); and (2) final HCLs. Table A sets forth EPA's
final and proposed HCLs. In the event that HCLs are revised, or amended to
, include additional contaminants identified in south Adams County drinking
vater, the agency viII evaluate such revised or amended HCLs and amend the
4. Applicable or relevant and appropriate requirements are selected on a site-
specific basis. The selection of HCLs as the applicable or relevant and
appropriate requirement for this operable unit is not intended to establish
precedent for remedial action at other sites or operable units, including,
but not limited to, ground water and surface water restoration, and is not
intended to establish precedent for any contaminants not identified in south
Adams County drinking water.
-------
.
Record of Decision, if appropriate, to require that the remedy attain the
revised or amended HCLs and assure adequate protection of human health.
The Agency expects that the HCLs will drive the design and operation of the
remedy. By not exceeding HCLs, the selected remedy will assure protection'
of human health for other hazardous substances, pollutants, or contaminants
identified in south Adams County drinking water for which HCLs have not
been proposed or finally promulgated. In any event, the selected remedy
will at least attain a level of control for such other hazardous
substances, pollutants, or contaminants that falls within a total risk
f -4 -7
range 0 10 to 10 over a 70-year lifetime exposure, with a goal of
attaining a level of control that reflects a 10-6 risk.
NESBAPs for vinyl chloride and benzene are relevant and appropriate in the
event air stripping is needed to treat vinyl chloride (40 CPR part 61,
subparts F and J).
,
.
".
Pretreatment standards promulgated pursuant to Section 307 of the Clean
Vater Act are applicable or relevant and appropriate in the event that the
selected remedy involves the discharge, indirect discharge, or introduction
of pollutants into a publicly owned treatment works from a source regulated
under Sections 307(b), (c), or (d) of the Clean Vater Act. The remedy
currently does not contemplate such a discharge, indirect discharge or
introduction of pollutants.
The State of Colorado provided BPA with a list of applicable or relevant
and appropriate State standards, requirements, limitations, or criteria
("State requirements") for this operable unit on January 8, 1987. The
State aaended its list on Harch 17, 1987 to delete several requirements and
add an additional requirement. BPA has reviewed the p~oposed State
requirements under the criteria set forth in Section 121(d) of CBRCLA, and
determined that certain provisions within the following State requirements
generally are applicable or relevant and appropriate:
-------
1.
The Colorado Hazardous Vaste Act and Regulations
Applicable to the extent the selected remedy involves the
generation, transportation, treatment, or storage of hazardous
waste in the spent granular activated carbon. The selected remedy
does not contemplate disposal of hazardous waste.
2.
The Colorado Primary Drinking Vater Regulations
Applicable or relevant and appropriate to the drinking water which
will be supplied to the public through the selected remedy, for
contaminants identified in the ground water which supplies the
SACVSD supply wells.
3.
The Colorado Air Quality Control Regulations
Applicable or relevant and appropriate to fugitive particulate
emissions and emissions which may result from the selected remedy
if air stripping of vinyl chloride is required, or if storage or
transfer of volatile organics compounds is required.
4.
The Colorado Noise Abatement Statute
,
Applicable or relevant and appropriate to establish maximum
permissible Aoise levels for construction or operation of the
selected remedy.
.
5.
The Colorado Vildlife Statutes and Regulations
Applicable to the extent the selected remedy involves the taking,
possession, transportation, exportation, shipment, removal,
capture, or destruction of wildlife. The selected remedy does not
contemplate any of these activities.
6.
The Vater Vell and Pump Installation Contractor Act and Regulations
Applicable or relevant and appropriate to pump installation. The
selected remedy does not contemplate the construction of vater
wdb. .
7.
Historical, Prehistorical, and Archaeological Resources Act
Applicable or relevant and appropriate if the selected remedy
involves the investigation, excavation, gathering, or removal from
the natural state of any historical, prehistorical, and
archaeological resour~es within the state. The selected remedy
does not contemplate any of thes~ activities.
-------
. .
8.
The Colorado Vater Quality Control Act and Regulations
Applicable or relevant and appropriate to the extent the selected
remedy involves the discharge of pollutants to waters of the State
of Colorado. The selected remedy does not contemplate such a
discharge.
A detailed evaluation of the State requirements is set forth in Appendix B.
The selected remedy will at least attain the legally applicable or relevant
and appropriate State requirements identified in Appendix B.
RECOMMENDED ALTERNATIVE
The remedy recommended is a granular activated carbon treatment system and
regeneration of spent carbon. The recommended alternative is a cost
effective remedial alternative that effectively mitigates and minimizes
threats to and provides adequate protection of public health. Cost,
technology, reliability, and permanency, and the effect on the public
health were evaluated in selecting this alternative from among those that
provide adequate protection of public health.
,
The GAC system will treat contaminated water from the South Adams County
Vater and Sanitation District (SACVSD) drinking water supply wells prior to
its consumption as drinking water. The GAC system will remove the
hazardous substances of primary concern from the drinking water to levels
which will assure protection of human health and attain applicable or
relevant and appropriate requirements. In the event that. other volatile,
semi-volatile, and non-volatile organic compounds are identified in ground
vater supplying the SACVSD veIls, the GAC system viII treat such hazardous
substances to a level that viII assure protection of human health vithout
modification and attain applicable or relevant and appropriate
requirements.
-The GAC system may not treat vinyl chloride to acceptable levels;
therefore, the system will be designed so that an air stripping facility
can be added to treat vinyl chloride in the event that vinyl chloride
-------
detected upgradient of the SACVSD supply wells poses a threat to the SACVSD
and public health. EPA will continue to monitor periodically for vinyl
chloride to determine whether it presents a threat to public health.
Additionally, in order to assure that the remedy operates effectively and
provides adequate safe drinking water supplies for the estimated SACVSD
water demand of 12.0 "GD, the remedy consists of the replacement of
existing well pumps and motors, the installation of transmission piping,
and the construction of laboratory and office space necessary to operate
and analyze this 12.0 "GD system.
Spent carbon from the GAC treatment system will be regenerated at an
incinerator in compliance with sections 3004 and 3005 of SVDA, in
accordance with section 121(d)(3) of CERCLA. The currently estimated
capital costs for the GAC system are $8,869,000 (Table 7). If an air
stripper to treat vinyl chloride is ~equired, the total capital costs woul~'
be increased by $1,~31,000 (Table 7).
To assure protection of the public health in the interim period between
approval of the Record of Decision and completion and operation of the
selected remedy, the temporary GAC treatment system, installed in June 1986
under EPA's removal authority to treat SACVSD drinking water will continue
to be leased and operated and demobilized, until the permanent system is on
line. The temporary system is designed to treat contaminated ground water
to levels at or below Maximum Contaminant Levels established under the Safe
Drinking Vater Act. The currently estimated operation and maintenance
costs for this temporary GAC treatment system are $31,000/month (Table 7).
The least costly alternative, air stripping without off-gas treatment, only
transfers the volatile organic compounds from a water ~edia to the
atmosphere and does not result in a permanent and significant decrease in
the toxicity, mobility, and volume of the hazardous substances and was,
therefore, rejected. This alternative does not achieve the preference of
CERCLA section 121(b) for permanent remedies, and was therefore rejected.
-------
~
The air stripping with off-gas treatment alternatives ranked equally with
the GAC alternative in terms of cost, ability to protect public health,
technical feasibility, environmental impacts, and treatment which
permanently and significantly reduces the mobility, toxicity, and volume of
volatile organic compounds. However, the GAC alternative is recommended
over air stripping with off-gas treatment. In the event that other
volatile, semi-volatile, and/or non volatile organic compounds are
identified in ground water supplying the SACVSD wells, the GAC system will
have the greatest capability of the treatment alternatives evaluated to
treat a wide spectrum of such hazardous substances to a level that will
assure protection of human health, without modification. Capital costs for
the recommended alternative are listed in Table 7.
The State of Colorado and the SACVSP have been consulted and concur with
the selected remedy (Appendix C).
,
The action will require future operation and maintenance activities to
assure the continued effectiveness of the remedy. O&H activities include
electric power, chemicals, maintenance, repair, and labor. O&H costs are
shown on Table 8.
SCHEDULE
The following key milestones have been established for this project:
Approve Remedial Action (sign ROD)
Award Cooperative Agreement to SACVSD
Initiate Design
Complete Design
Start Second Operable Unit RI/FS
Award Cooperative Agreement to SACVSD
for Construction
Begin Construction
Startup of GAC Units
Complete Construction
for Design
June 1987
June 1987
June 1987
January 1988
Harch 1987
December 1987
February 1988
September 1988
December 1988
-------
TABLE 7
CAPITAL COSTS - CARBON ADSORPTION
Item
Cost
1. Land
2. Transmission System
a) leplacement VeIl Pumps,
VeIl No. B.P.
2 -so
3 100
5 150
14 50
15 25
16 40
17 150
b) Distribution System
$ 250,000
Motors, Controls
Sub-total Transmission
31,900
47,300
61,300
31,900
23,500
28,000
61,300
830,700
System $1,115,900
3. Buildinga
15,700 S.F.; 30 ft.bhigh
4. Office Building and Lab
3,550 S.F.
5. GC Equipment
6. Chlorination and Chemical Feed Equipment
7. Sitework/Landscaping
8. Carbon Adsorbers, Piping, Instrumentation,
9. Carbon - Initial Charge (400,000 lb)
Sub-total
Clearvell
$1,020,500
284,00Q I
50,000
105,000
166,200
3,300,000
400,000
$6,691,600
Contingency (15%)
Engineering, DesignC
Construction Engineer (5%)
Sub-Total
1,003,700
839,100
334,600
$8,869,000e
10. Temporary GAC System Lease and Carbon Changeout Costs
(needed to fund as of 12/86)
TOTAL .
908,900
$9,777,900e
a
Based on $65/S.P. Price is based upon a steel frame building. The
exterior valls are concrete block. Bstiaated added square foot costs
for other exterior fiDishes are: ..
Precast Concrete Panels $3/S'.F.
Insulated Metal Panels $O/S.F.
Pace Brick on Common Brick $7.50/S.P.
Pootnotes continued on page 35.
-------
.
TABLE 7
. CAPITAL COSTS - CARBON ADSORPTION (Continued)
b Based on $80/S.F.
c SACVSD
d Based on:
Funds Available 12/86
$500,800
105,000
294,400
131,100
34,400
42 ,000
$1,107,700
198,800
Lease costs from 1/1/87: $23,846/Ho x 21 Ho .
Honthly Honitoring and O&H: $5000/Ho x 21 Ho
GAC Changeout
Demobilization of Treatment Plant
Demobilization of Temporary Structure
Contingency $2000/Ho x 21 Ho
$908,900
e
Additional estimated costs for a~ air stripping facility to treat vinyl
chloride, if ~eeded, are $1,231,000. This figure is based on estimated'
capital cost of $962,000 plus contingency (15%), engineering (8%), and.
'construction.engineering (5%). Details are given in Attachment C of
the Responsiveness Summary. Total capital costs including the air
stripping facility would be $10,100,000. Total costs, including
continuation of leasing, operation, and demobilization of the temporary
GAC system would be $11,008,900.
-------
TABLE 8
ANNUAL O&H COSTS AND EQUIPHENT REPLACEHENT COSTS - CARBON ADSORPTION
Item
Cost
1. Labor
1 Operator
1 Laborer
Hechanical
(Class A)
2920 x $20
2080 x $15
200 x $20
$ 58,400
31,200
4,000
& Electrical
2. Power
Vells
Building HVAC and Lighting
Chemical Feed Pumps (1 kw)(24 hrs/day)
(30 day/mo)(12 mo)($0.06/kw)
44,000
24,000
500
3. Carbon Replacement
(400,000 lb/year) ($1.00/lb)
400,000
4. CAC Contactor Haintenance
$1,500/unit/changeout for Insp. & Haint.
25 , 000'
'-0-
5. Chlorine (By. District)
6. Sodium Hexametaphosph,te
Dose 0.5 mg/l . 40 gal/week
1 Drum/Veek x $326/Drum x 52
Annual O&H
17,000
$ 604,100
7. Equipment Replacement Costs (over 30 years)
a. Vell Pumps every 10 years (by district)
b. Chemical Feed every 10 years (2) (50,000)
c. Lining Replacement every 5 years (5) (68,000)
Total
-0-
100,000
340,000
$ 440,000
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FUTURE ACTIONS
A subsequent feasibility study is ongoing which will address whether
aquifer restoration is appropriate. EPA is currently conducting the RI
studies necessary to support such a feasibility study (FS), and the FS
report is anticipated in early PY 1988. EPA is investigating whether or
not further response actions, in addition to aquifer restoration, may be
necessary at the EPA's aHA Off-Post site to protect human health and the
environment. The Army is conducting on-post RI/FS activities and is
scheduling completion of a cleanup master plan in 1989.
,
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APPENDIX A
FINAL
RESPONSIVENESS SUMMARY
FOR THE FIRST OPERABLE UNIT
THE ROCKY MOUNTAIN ARSENAL OFF-POST RI/FS SITE
COMMERCE CITY, COLORADO
JUNE 1987
The u.S. Environmental Protection Agency (EPA) has
prepared this community relations Responsiveness Summary for
the first operable unit of the EPA portion of the Rocky
Mountain Arsenal (RHA) Off-Post site. This Responsiveness
Summary is divided into the sections below.
Section I.
Section II.
Section III.
Introduction and Background. This section
provides a brief introduction to the site as
'well as investigations and remedial actions
taken to address the drinking water
contamination.
,
The Community Relations Program at the RHA
Off-Post Site. This section provides a brief
history of community relations activities
during the remedial investigation activities
at the site.
Summary of Major Comments Received and EPA's
Responses. This section summarizes comments
received in the categories below.
o
Comments received from inception of the
project through November 1986.
-------
.
o
Comments received during the public
comment period (December 12, 1986 through
January 7, 1987) on the Remedial
Investigation and Feasibility study
Reports for the first operable unit.
o
Comments raised after the close of the
public comment period.
This section categorizes written and oral
comments by related topics and generally
indicates the sources of the comments.
Summaries of EPA's responses to these
comments are also provided.
I.
INTRODUCTION AND BACKGROUND
,
A description of the Off-Post RI/FS site is included in the
Remedial Investigation and Feasibility Study Reports.
In the summer of 1985, area media began to publish stories
about the chemical trichloroethylene (TCE) that had been
discovered by EPA and the South Adams County Water and
Sanitation District (SA~SD) in some of the water district's
public wells and some private wells. SACWSD provides water to
the 30,000 residents of Commerce City. The stories raised
considerable concern among area residents and their elected
representatives at all levels. EPA determined that the TCE
contamination warranted more immediate attention, and that a
. temporary system to deliver clean water to affected Commerce
City residents would be a first priority in the response actions
. .
at the site. Initial activities included "installation of
temporary granular activated carbon (GAC) treatment systems at
three of the SACWSD well sites and a private well hookup
-------
program, under ~PA's removal authority.
Treatment of the south Adams County public drinking water
with a permanent treatment system has been designated the first
operable unit of EPA's RMA Off-Post site. For the second
operable unit, EPA will investigate the potential for control of
contaminant migration and source removal. A remedial
investigation and feasibility study (RI/FS) for the first
operable unit was completed in the fall of 1986. EPA proposed
to install a permanent centralized granular activated carbon
water filtration system as the 'preferred alternative for
remedial action for the first operable unit, and conducted a
public comment period (December 12, 1986 through January 7,
1987) on that and other alternatives. Other treatment
alternatives evaluated included air stripping for different
types of contaminants and a com~ination of GAC with air
stripping.
,
In general, community reaction to EPA's preferred
alternative of installing a granular activated carbon filtration
system has been favorable. The majority of commenters supported
that alternative, including the Citizens Against Contamination
(CAC), the Colorado Department of Health (CDH), the South Adams
County Water and Sanitation District (SACWSD), the Tri-County
Health Department, the City of Commerce City, the Adams County
Commission, and Adams County School District 14. The only
exception was the law firm of Holme, Roberts and Owen. The U.S.
Army commented that "the treatment alternative selected appears
technically sound for remediation of the water to an acceptable
quality." Some commenters had specific technical questions
regarding the ground water models in the RI/FS,.Report and
regarding the risk assessment. All the comments received and
EPA's responses are summarized in Section III of this
Responsiveness Summary.
-------
II.
THE COMMUNITY RELATIONS PROGRAM AT EPA'S PORTION OF THE RHA
OFF-POST SITE
A summary of community relations activities conducted by
.EPA is included in Attachment A.
Since the discovery of TCE in the ground water, community
concern about EPA's portion of the RMA Off-Post site has been
high. On several occasions, new information about the site has
been front-page news in one or both of the Qenver daily
newspapers. A citizen interest group, Citizens Against
Contamination (CAC), was formed in the summer of 1985 at the
time of the discovery of the TCE in the ground water, and it has
been active since that time.
EPA'S community relations program has responded to this
interest at the. site. In the spring of 1986, the Agency
prepared and distributed widely a videotape that answered common
questions residents have had regarding the TCE in their water.
EPA also has published three fact sheets on the site. The first
one, in February 1986, provided the public with a directory of
agencies and contacts for issues relating to the site. The
second fact sheet, in August 1986, described the site, RI/FS
plans at the site, other studies in progress in the area, major
agencies involved at the site, and the Superfund community
relations program. The third fact sheet, issued in December
1986 upon the release of the RI/FS Report, described the
remedial alternatives under consideration and provided
information about the public comment process.
,
At key points during the RI/FS, EPA has issued press
releases and held press conferences to keep the public informed
as new information became available. EPA has attended all of
the CAC public meetings. These meetings were held July 24 and
November 25, 1985; and February 13, March 5, and May 22, 1986.
-------
In addition, EPA has responded to numerous citizen, vendor, and
press inquiries; kept elected U.S. officials informed of site
activities; and met with area residents on many occasions.
EPA released the draft RI/FS Report on the first operable
unit to the public on December 12, 1986, and held a public
comment period on the report from December 12, 1986 through
January 7, 1987. The Agency provided an opportunity for a
public meeting during or following the public comment period but
did not receive any request for such a meeting.
III.
SUMMARY OF COMMENTS RECEIVED AND EPA'S RESPONSES
This section summarizes concerns the
during the remedial investigation for the
and EPA's responses to these concerns.
public has expressed
first operable unit
,
A.
Summary of Commen~s Received from Incep~ion of ~he Remedial
1nves~iga~ion Through November 1986
The high level of community interest in EPA's portion of
the RMA Off-Post site is shown in a continuing pattern of
community concerns, questions, and comments expressed to EPA.
EPA has summarized the comments received during the remedial
investigation through November 1986 in the four groups below.
o
Health Concerns.
o
Technical Issues.
o
Economic and Social Issues.
o
Process Issues.
-------
EPA's responses to the public's questions and comments are
summarized following each item.
Health Concerns
1.
Comment: Numerous residents have expressed concern that
contaminated water could cause health problems.
EPA'S Response: EPA prepared a Preliminary Risk Assessment
(Camp Dresser & McKee, April 17, 1986) and a Public Health
Endangerment Assessment (part of the Remedial Investigation
Repor~, Camp Dresser ~ McKee, December 1986) to address the
health risk. In May 1986, EPA installed a temporary water
treatment facility to treat ground water from SACWSD public
water supply wells. The t~mporary system. is providing safJ.
~
drinking water at levels below the Safe Drinking Water Act
Maximum Contaminant Levels. In the summer of 1986, EPA
connected all willing households with private drinking
water wells to the newly clean public water supply.
2.
Comment: A number of 'residents expressed confusion
regarding the meaning of drinking water standards.
EPA'S Response: Under the Safe Drinking Water Act (SDWA),
EPA has set Maximum Contaminant Levels (MCLs) and Maximum
Contaminant Level Goals (MCLGs) for contaminants in public
drinking water supplies. MCLGs are non-enforceable health
goals which are set at levels which would result in no
known or anticipated adverse health effe~ts with an
adequate margin of safety. MCLs are enforceable standards
and are set as close to the MCLGs as is feasible. MCLs are
based upon treatment technologies, costs and other
feasibility factors such as the availability of analytical
-------
methods, t~eatment technologies and costs for achieving
various levels of removal. See generally, 50 Fed. Reg.
. .
Nov. 13, 1985 and the Safe Drinking Water
Section 300(f) et seq.
46880 et seq.,
Act, 42 U.S.C.
3.
Comment: Some residents asked questions about the risks
associated with different routes of TCE exposure (i.e.,
from drinking, or from vapors during cooking or bathing).
They also wanted to know how long they have been exposed to
the contamination and whether a long period of exposure
will result in grave health effects.
EPA's Response: The EPA investigation for the first
operkble unit focuses on the remediation of current public
water supply contamination from SACWSD wells. TO-date, the
studies have not determined the length of previous exposure
SACWSD customers have had to contaminated water. ,
As described above, EPA twice prepared documents that
address risks to public health associated with untreated
SACWSD ground water. The risk assessments assumed that
SACWSD customers ingested two liters per day, and showered
for ten minutes per day, with untreated water. A potential
excess cancer risk of 10-6 (one excess cancer in every one
million individuals ,exposed throughout their lifetimes) is
used by EPA as a guideline for determining an acceptable
level of exposure within one or two orders of magnitude.
The risk assessments showed that exposure by ingestion or
inhalation, or by both routes concurrently, to untreated
water from the SACWSD system may pose an unacceptable
health risk. The additive excess cancer .risks for lifetime
exposure by ingestion and inhalation range from 2 x 10-6 to
1 x 10-4 (Table 6-8 in the RI Report); Installation of the
temporary treatment system, however, reduced the exposure
to contaminated water through the SACWSD system to MCLs
-------
.. . .'
. .. .
... o. ...."
: ... ~ . ..... '. ..
establishe4 under the SDWA.
4.
Comment: Some residents asked whether the unpleasant taste
of the water indicates the presence of contamination.
EPA's Response: The levels of TCE and other organic
contaminants 'in the public water supply are well below
concentration where the taste of the water would be
affected.
Technical Issues
!.
Comment: In reviewing the draft RI/FS Report provided to
the Memorandum of Agreement (MOA) parties, CDH expressed
the concern that the RI/FS.Report focused on a range of
contaminants that was too limited and that the
characterization of sources on and off the Arsenal was
substantially incomplete. CDH also said that since non-
volatile organics have been identified in the aquifer, the
assessment of proposed treatment systems must show how
these contaminants would be treated.
,
EPA's Response: EPA addressed CDH's comments in the final
RI/FS Report. The RI/FS did not characterize sources on
and off of the Arsenal. A future operable unit report may
address sources that are currently being characterized by
other EPA studies and the u.S. Army.
2.
Comment: In reviewing the draft RI/FS Report provided to
MOA signers, CDH stated that use of air s~ripping without
emission controls wou~d not meet Colorado regulations to
protect the air, or requirements under the 1986 Superfund
Amendments and Reauthorization Act (SARA) to provide a
permanent remedy.
-------
EPA's Response: The final FS Report does address 1986 SARA
preference for providing permanent solutions, and narrows
the possible alternatives to those that would provide a
permanent reduction of the toxicity, mobility, and volume
of the contaminants. Also, EPA identified Colorado
applicable, or relevant and appropriate requirements
(ARARs) for air emissions in the Record of Decision.
Economic and Social Issues
1.
Comment: Several residents expressed concern that
property values would fall as a result of negative
publicity about contamination in their water.
their
I
EPA's Response: Implementation of temporary and permanent.
ground water treatment systems .provides drinking. water to
SACWSD customers that meets all criteria set under the
SDWA. SACWSD officials have met with local residents and
realtors to assure all parties that drinking water is not a
problem to residents.
2.
Comment: Some local officials and residents expressed
concern that economic development in the area would be
depressed as a result of publicity about the RMA Off-Post
RI/FS site.
EPA's Response: Implementation of temporary and permanent
ground water treatment systems provides drinking water to
SACWSD customers that meets all criteria set under the
SDWA. SACWSD officials have met with local residents and
realtors to assure all parties that drinking water is not a
problem to residents.
-------
3.
Comment: Several residents expressed concern about costs
that individuals will bear due to plumbing damage and other
problems r~sulting from the contamination found at the RMA
Off-Post site and efforts to clean it up.
EPA's Response: The volatile organic compounds that were
present in the SACWSD water prior to initiation of
treatment in May 1986 are not corrosive and would not cause
damage to plumbing. However, SACWSD ground water is
naturally hard, which might cause damage to plumbing from
scaling. SACWSD follows guidelines on water pressure set
by the Colorado Department of Health.
4.
Comment: Some local officials and community residents
expressed concern about the negative reputation the
contamination will give the community.
,
EPA's Response: Implementation of temporary and permanent
. ground water treatment systems provides drinking water to
SACWSD customers that meets all criteria set under the
SDWA. SACWSD officials have met with local residents and
realtors to assure all parties that drinking water is not a
problem to residents.
Process Issues
1.
Comment: A number of local officials and area residents
expressed confusion about the respective roles of the
Colorado Department of Health, EPA, the South Adams County
Water and Sanitation District, and the U.S". Army.
EPA's Response: EPA has coordinated its activities
conducted under the Off-Post RI/FS with the u.s. Army, the
State of Colorado and SACWSD to avoid unnecessary
-------
3.
duplication of effort and to ensure that pertinent
information is shared by all parties. EPA, the CDH, the
u.s. Army and Shell Chemical Company entered into a
Memorandum of Agreement on December 6, 1982 for the
cooperation, exchange of information, and participation of
the parties in the development and implementation of
appropriate response actions for releases of contaminants
at RMA. EPA has responsibility for conducting an RI/FS in
the area shown in Figure 1 of the Record of Decision,
pursuant to CERCLA, the National Contingency Plan (NCP) and
executive orders delegating the functions of the President
under CERCLA.
2.
Comment: Several residents and local officials expressed
concern that studies were getting in the way of action at
the site.
,
t
EPA's Response: Superfund (CERCLA) and the NCP require
specific site. investigations and analysis of cleanup
alternatives, ~ 40 CFR Section 300.68 of the NCP and
Sections 104 and 121 of CERCLA, as well as public comment
prior to implementation of remedial action. These studies
are necessary in order to assure protection of public
health. The removal actions (to provide the temporary GAC
treatment system and to connect the households using
private wells to the public system) were taken as quickly
as NCP guidelines and funding availability would allow.
Comment: A number of people expressed concern about who
would pay for the studies and the cleanup of contamination,
and from whom EPA and the U.S. Army could-"recover the
costs.
EPA's Response: The u.S. Army has provided a total of
$7,000,000 to EPA for use in the selection, design and
-------
implementation of response actions to address TCE
contamination in SACWSD ground water. EPA is continuing to
investigate. other potential sources of contamina~ion. If
such sources are identified, EPA may sue potentially
responsible parties in order to recover study and cleanup
costs. EPA may seek additional funds from the U.S. Army.
4.
Comment: In reviewing the draft.RI/FS Report provided to
MOA signers, CDH objected to the limited review time of one
week, as requested by EPA. CDH said that the MOA
stipulates a review period of 60 days for MOA parties and
that this rush effort may misrepresent the nature of the
long-term problem. CDH added that its plan review and
fina~ concept approval process would require 45 days prior
to final CDH approval.
EPA's Response: CDH's comments were received and
incorPOrated into the final RI/FS Report.
I
B.
Summary of Commen~s Received in December 1986 and January
1987, and EPA'. Responses
The comments received on the first operable unit RI and FS
documents during the pub~ic comment period between December 12,
1986 and January 7, 1987 are grouped into the five categories
listed below. Each comment is foliowed by a summary of EPA's
response to the comment.
o
Remedial alternative preferences.
o
Technical comments.
o
Health concerns.
-------
o
Financial comments.
o
Community relations concerns.
"Remedial Al~erna~ive Preferences
1.
Comment: Commenters generally favored EPA's preferred
remedial alternative of installation of a granular
activated carbon treatment system. These commenters
included Citizens Against Contamination (CAC), SACWSD, CDH,
the City of Commerce City, the Adams County Commission,
Adams County School District 14, and the Tri-County Health
Department. CAC expressed the opinion that not all
contaminants have been identified as yet, and supported the
addition of air-stripping ~owers to remove potential
concentrations of other contaminants that may not be
removed b~ t~e GAC system.
I
EPA's Response: The Record of Decision is based upon
implementing the GAC alternative. In addition, the remedy
provides for the possible addition of air stripping units
if vinyl chloride is detected in SACWSD drinking water and
poses a threat to public health. Attachment B to this
Responsiveness Summary presents a risk assessment for vinyl
chloride emissions to the air from such air strippers. The
risks are within EPA's approximate guidelines for
determining an acceptable level of excess cancer risk. A
risk assessment for other contaminants emitted from an air
stripper is presented in Appendix B of the FS Report.
Attachment C presents the best estimate ~ost at this time
for such air strippers.
2.
Comment: One citizen expressed the opinion that Commerce
City should use the Denver municipal water system.
-------
. ,.
EPA's Response: SACWSD has its own water rights in the
alluvial aquifer. Further, the cost of buying into the
Denver system would be approximately $30,000,000, which far
exceeds the costs of the other available remedies evaluated
without providing substantially greater public health
benefits.
Technical Commen~s
1.
Comment: A contractor representative of the U.S. Army
asked what problems had been observed with the leased
activated carbon system currently in operation in SACSWD.
EPA's Response: SACWSD op~rations personnel report that
there are no operational prOblems with the leased system.
and .that the system produces effluent that meets SDWA
criteria. However, they do report that the system is
undersized to meet peak water demands.
,
2.
Comment: A contractor representative of the U.S. Army
expressed the opinion that the FS Report does not appear to
. address all reasonably available alternatives and
technologies, and does not appear to provide sufficient
justification for elimination of alternatives.
EPA'S Response: The FS Report was prepared based on the
NCP and the EPA guidance document, "Guidance on Feasibility
Studies Under CERCLA." Justifications for elimination of
alternatives were consistent with the NC~.
3.
Comment: The SACWSD expressed the opinion that the
possible addition of air-stripping to the treatment
will require use of a clearwell system.
system
-------
EPA'S Response: The clearwell system will be implemented
as part of the facility design. The expected cost would
add $387,000 to the treatment system cost, which is
included in the cost shown in Table 3-4 of the FS Report in
the Record of Decision.
4.
Comment:
CDH commented
that the proposed parallel
treatment facility may lead to
blending the effluents.
configuration for a GAC
operational problems in
EPA's Response: Each carbon bed will be monitored to
determine when it is necessary to take the bed out of
service for carbon replacement. The monitoring of
individual carbon beds and the treatment plant effluent
will ensure compliance with applicable, or relevant and
appropriat~ requirements.
,
5.
Comment: The U.S. Army, the law firm of Holme, Roberts and
Owen, and the Colorado Department of Health questioned the
use of the preliminary flow and transport models in the
First Operable Unit RI/FS Report. A summary of these
concerns is listed below.
o
No results of sensitivity analysis for model parameters
or boundary conditions were presented in the report.
o
Several commenters expressed concern about the use of
steady state rather than transient calibration.
o
Detailed summaries of model parameters.~ere not
presented in the report.
o
The solute transport model was not calibrated against
current conditions.
-------
w
o
The flow system has not been completely characterized.
o
Additional aquifer tests throughout the area to be
modeled are required.
o
Results of the modeling are preliminary in nature.
o
Field data for total organic carbon are required for
realistic assessment of contaminant retardation. The
u.s. Army said that their studies indicate almost no
retardation potential in the aquifer material.
EPA's .Response: The RI Report states that the preliminary
. modeling efforts were intended to provide insight to the
processes controlling contaminant transport, a framework
for summarization of the a~ifer systems~ and the current'
~
best estimate of future contaminant concentrations.
Results obtained from these preliminary efforts are
adequate for producing the preliminary estimates of future
concentrations at SACWSD wells needed to assist in design
of the first operable unit. Insufficient detailed field
information in the vicinity of the plumes is currently
available for explicit calibration of the models. Studies
are planned for the second operable unit to address these
data gaps, since plume definition and remediation will
require more accurate data. Availability of more data may
justify the complexity of transit calibration of future
models and allow additional uses of the model. The
applicability of this approach will be assessed as
additional data are gathered.
In addition, technical information on modeling methodology
and parameters is available in the administrative record.
6.
Comment:
A contractor representative of the u.s. Army
-------
asked why alternative remedial actions for semi-volatile
organics are being considered when they were not defined as
a problem in the RI Report. He expressed the opinion that
more documentation is needed in the FS Report to justify
how contaminants of concern were determined. He asked if
the detection of TCE was the only reason for concern and
whether there were other contaminants that caused problems.
EPA'S Response: The final RI Report presents data
identifying the presence of a wide range of low level semi-
volatile and non-volatile compounds scattered in areas
potentially upgradient of SACWSD production wells. The
contaminants of concern are detailed in Section 6
(Endangerment Assessment) of the RI/FS Report. The
chemicals reported most frequently and at the highest
concentrations in validateQ monitoring well and private
,
well data are: 1,1-Dichloroethane, 1,1-Dichloroethylene, .'
trans-1,2-Pichloroethylene, 1, 1, 1-Trichloroethane,
tetrachloroethylene and trichloroethylene. These chemicals
may be considered ground water contaminants of primary
concern. A number of other organic chemicals including
toluene, cis-l,3-dichloropropene, phenol, vinyl chloride,
dibromochloropropane, 'aniline, methylene chloride, carbon
tetrachloride, chloroform, heptachlor epoxide, dieldrin,
and several phthalate esters also were detected in some
ground water samples from the EPA Off-Post study area.
However, these chemicals were detected infrequently and
generally at low concentrations. In addition, identified
potential contaminant sources both on and off the RMA are
currently being characterized and are potential sources of
semi-volatile and non-volatile compounds.-. The potential
future threat from t~ese compounds formed the basis for
considering an alternative of air stripping to address
semi-volatile compounds. This alternative was eliminated
in the initial screening of alternatives because the cost
-------
of this alternative far exceeds the capital and O&M costs
of other alternatives evaluated and does not provide
substantialIy greater public health protection. Since the
costs of the GAC and other air stripping alternatives (for
volatiles only) were comparable, EPA recommended the GAC
alternatives over such air stripping alternatives because
the GAC system will have the greatest capability, without
modification, to treat a wide spectrum of such hazardous
substances to a level that will assure protection of public
health.
7.
Comment: The law firm of Holme, Roberts and Owen and the
contractor representative of the U.S. Army said that the
treatment facility should not be designed to treat ground
water based on the results of the preliminary modeling
effort, but should be based upon the current situation in
south Adams County.
,
EPA'S Response: The risk assessments showed that exposure
by ingestion or inhalation, or by both routes concurrently,
to untreated water from the SACWSD system may pose an
unacceptable health risk. The additive excess cancer risks
for lifetime exposure by ingestion and inhalation range
from 2 x 10-6 to 1 X 10-4 (Table 6-8 in the RI Report). The
risk assessment$ were based on actual current sample
results from SACWSD wells and not upon future
circumstances. Based upon the current threat shown in the
risk assessments, the Agency determined that remedial
action was required.
The GAC system and other alternatives wer~ designed to
address both current and predicted future concentrations in
order to assure adequate protection 9f public health.
However, no change in design of the alternatives would be
required within the range of existing and future predicted
-------
concentration levels. The design is based on the quantity
of water to be treated.
8.
Comment: A contractor representative of the u.s. Army
questioned whether sufficient studies have been conducted
to ensure that bedrock wells are clean enough for blending
with treated water. The U.S. Army recommended that bedrock
wells be monitored if blending water from them is going to
be considered.
EPA'S Response: Data available to-date indicate that the
quality of the water from the bedrock aquifers is adequate
for blending. Monitoring will continue in the future to
verify this suitability.
9.
Comment: The contractor representative for the U.S. Army
commented that a prevailing northward flow of ground water'
.
would take contamination directly from the Woodbury
Chemical Company Superfund site into the study area for the
Rocky Mountain Arsenal Off-Post site. The U.S. Army
expressed the opinion that the "ground water divide" should
be explained.
EPA'S Response: The groundwater divide is present due to
the presence of a high bedrock trend separating the South
Platte Valley and the north-south trending paleochannel
that parallels Quebec Street. This flow configuration
limits the potential for contribution of contamination to
SACWSD wells from the Woodbury site.
10.
Comment: The contractor representative f~r the U.S. Army
asked when the FS for the other operable units will be
performed and whether. surface water will be considered an
operable unit.
-------
11.
12.
EPA's Resp~nse: The second operable unit will consider
primarily aquifer cleanup options. Treatment of ground
water used for drinking serves the dual purpose of meeting
SACWSD demand with their existing water rights and aiding
in ultimate cleanup of the aquifer system. EPA will
evaluate surface water contamination in the study area.
Comment: The law firm of Holme, Roberts and Owen expressed
the opinion that the risk assessment is based on
unrealistically conservative estimates of the situation.
They said that if EPA had used more realistic estimates,
the hazards may not be as severe as presented.
EPA's Response: The risk assessment techniques utilized
are standard to EPA and utilized at Superfund sites. These
techniques were developed after considerable scientific and
public co~ent. Quantitie~ of water ingested and water I
utilized for other purposes, such as showers, are
realistic, worst-case estimates which assure adequate
protection of public health. This approach does provide a
basis for comparison for the risk analysis.
Comment: The consultant to SACWSD expressed the opinion
that if EPA determines that Maximum Contaminant Level Goals
(MCLGs) should be met by the water treatment facility, then
SACWSD should verify that the recommended downflow, fixed-
bed GAC treatment process is capable of cost-effectively
meeting these stringent standards.
EPA's Response: EPA has determined that the Maximum
Contaminant Levels (MCLs) in the Safe Drinking Water Act
are the applicable or relevant and appropriate requirements
- .
for this operable unit.
-------
13.
14.
15.
Comment: CDH provided a list of the applicable or relevant
and appropriate state standards, requirements, limitations,
and criteria ("requirements") for the management of wastes
at the RMA On- and Off-Post sites. CDH reserved the right
to amend the list if any more regulations or standards are
identified.
EPA's Response: EPA has discussed the list with the state,
the state has provided a revised list, and the Record of
Decision identifies the applicable or relevant and
appropriate state requirements.
,
Comment: CDH said it is the position of the state of
. .
Colorado that although permits may not be required for
certain activities at the Arsenal, the requirements of the
state of Colorado governing all information submittals,
notification requirements, monitoring, data collection, and
data reporting requirements are applicable at the RMA On-
and Off-Post sites.
~
EPA's Response: EPA's response is set forth in Appendix B
to the Record of Decision.
Comment: CDH, the U.S. Army, and the law firm of Holme,
Roberts and Owen made comments on the sources of
contamination at the RMA Off-Post site. Holme, Roberts and
Owen said that plume maps would help to identify sources of
concern rather than to infer that the Arsenal is the major
. .
source of many contaminants at the RMA Off-Post site. CDH
suggested that EPA remove from the FS Report all
disclaimers concerning the lack of intent to identify
-------
contributing sources of contamination at the site, since
the RI Report discusses potential sour~es of contamination
at length, and the purpose of an RI is to identify sources
of contamination. The contractor representative of the
U.S. Army stated that the contaminant concentration maps
presented suggest source areas other than RMA. The
modeling effort should be considered the initial phase of a
more detailed study using site specific data.
EPA's Response: Insufficient information on potential
sources is currently available for identification of or
apportionment of responsibility to individual sources. The
selection, identification, evaluation and design of
treatment alternatives for the SACWSD drinking water do not
require identification of the responsible sources. Efforts
to identify the responsible sources on and off the Arsenal
are continuing.
,
.'
Health Concerns
1.
Comment:
drink.
A local resident asked if the water is safe to
EPA's Response: EP~ explained that the temporary water
treatment system that EPA arranged'for SACWSD is providing
safe water at levels at or below the SDWA Maximum
COntaminant Levels until installation of the permanent
treatment system. EPA also explained the public comment
process and encouraged the resident to review the documents
describing the proposed remedial alternat~ves and to
comment on them.
-------
Financial Commen~s
1.
Comment: A-local resident asked if the expenditures on a
permanent water treatment system can be justified when, in
his opinion, SACWSD will eventually have to use surface
water in the future.
EPA's Response: EPA said that it is currently evaluating
how to clean up the ground water: thus, it is premature to
assume that surface water will have to be used in the
future. Additionally, the cost of providing surface water
far exceeds the cost of other alternatives evaluated,
without providing greater public health benefits.
2.
Comment: In the interests of cost-effectiveness, Citizens
Against Contamination recommended installation of the GAC
system as soon as possible~
I
.'
'.
EPA's Response: The Record of Decision is based upon
implementation of the GAC system alternative. The
permanent system should be in operation by September
1988.
Communi~y Rela~ions Concerns
1.
Comment: One resident expressed the opinion that the
problem of delivering clean water should be solved in
of growth.
terms
EPA's Response: EPA responded that it is the Agency's hope
that with a permanent system for providi~g safe water, the
citizens of Commerce City will not see a negative effect on
growth.
2.
Comment:
CAC and SACWSD both expressed appreciation to EPA
-------
for its concern about the problem, for the opportunity to
comment on the proposed remedial alternatives, and for the
cooperative- spirit in which they have worked. CAC added
that the process at the RMA Off-Post site has exemplified
what can be accomplished when citizens' groups and the
government work together.
EPA's Response:
No response required.
C.
Summary of Commen~. Raised af~er ~he Close of the Public
Commen~ Period
EPA received additional comments dated March 5, 1987 from
the u.s. Army. Although EPA is not required to respond to
c~mments received after the public comment period closes, the
Agency believes it is important to respond to these comments
because of the u.s. Army's suQstantial participation in the
project. The u.s. Army's general comments and EPA's responses
are summarized below. Certain comments raised in the u.s.
Army's March 5, 1987 letter of comment were raised earlier by
their contractor and have already been addressed in Section
111.B of this Responsiveness Summary.
I
.'
1.
Comment: The U.S. Army suggested that the title of the
R1/FS Report be changed. They said that RMA is just one of
many parties potentially responsible for the contamination
that exists in the SACWSD distribution system, and the
title should reflect this broader responsibility.
EPA's Response: The Agency has determined that
change is inappropriate. The RMA is a proposed
and RMA is one of twO. or more potential sources
Adams County ground water contamination.
a title
NPL site,
of south
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2.
Comment. ~he u.s. Army said that EPA's preference for the
GAC alternative relies heavily on possible future semi-
volatile and non-volatile contamination that cannot be
extrapolated from the existing data. The U.S. Army
recommended that additional justification be provided
before this method of treatment is selected as the
preferred alternative.
EPA's Response: The detailed
identified three alternatives
cost effectiveness analysis.
screening process in the FS
that were comparable in the
These alternatives are:
o
GAC.
o
Air stripping with off-gas treatment.
o
Air s.tripping with off-gas treatment at wells 14 and.'
16. .GAC at wells 2, 3, 5, 15 and 17.
Since the costs of these alternatives are comparable, EPA
recommended the GAC alternative over air stripping because.
of its ability to deal effectively with semi-volatile and
non-volatile organic compounds, without modification, in
the event such compounds pose a threat to SACWSD wells and
public health in the future.
3.
Comment: The U.S. Army stated that all of the air
stripping alternatives were evaluated and compared to the
GAC alternative based on their removal efficiency for
Diisopropymethylphosphonate (DIMP) and Dicyclopentadiene
(DCPD), two RMA-specific compounds not likely to be
encountered in the study area. If the treatment efficiency
. -
for semi-volatile and-non-volatile compounds is to be used
as an evaluation criterion, compounds likely to be
encountered in the study should be used.
-------
EPA's Response: Two basic air stripping alternatives were
developed. . The first evaluated air stripping of volatile
organic compounds. The second evaluated air stripping of
both VOCs and semi-VOCs including DIMP and DCPD. Both of
these alternatives were compared against GAC. Air
stripping of only VOCs was comparable on a cost-effective
basis to the GAC alternative. Air stripping for semi-
volatiles was excluded during the initial screening because
the cost of this alternative far exceeds the capital and
O&M costs of other alternatives evaluated and does not
provide substantially greater public health protection.
4.
Comment: The U.S. Army recommended that EPA give greater
consideration to the problems associated with using a GAC
system to treat polar compounds, such as vinyl chloride and
chloroform.. These compounds are as likely, if not more I
.
likely, to be encountered in the SACWSD system as those
semi-volatile. and non-volatile compounds considered as
problematic to the air stripping.
EPA'S Response: EPA is continuing to monitor for vinyl
chloride and other hazardous substances. The selected
remedy provides for the addition of an air stripping
facility to treat vinyl chloride in the event that vinyl
chloride poses a threat to the SACWSD supply wells and the
public health.
5.
Comment: The u.S. Army recommended that carbon disposal be
evaluated as part of the GAC alternative, as disposal may
be an important financial consideration 1ft final selection
of alternatives. The U.S. Army said problems with
obtaining liability insurance have made it increasingly
difficult and expensive to find suitable disposal and
regeneration facilities willing to accept used carbon from
-------
6.
RMA's own on-post GAC treatment systems.
EPA's Response: The vendors of GAC who
for supply of equipment and replacement
have access to, regeneration facilities
RCRA permits.
will be solicited
carbon all have, or
which are under
Comment: The U.S. Army expressed the opinion that the air
stripping alternative could be the most efficient and cost-
effective means of treating the SACWSD contamination
problem for the reasons listed below.
o
Both GAC treatment and air stripping merely transfer the
contamination from one medium to another: and
o
The contamination problem in the SACWSD system is solely
volatile organic in nature at this time. I
.
".
The U.S. Army added that a GAC unit could be added to the
treatment system later if it should become necessary
because of a future influx of semi-volatile and non-
volatile organic contamination.
EPA's Response: The GAC alternative transfers the VOCs
from water to the activated carbon. Spent carbon from the
GAC treatment system will be regenerated at an incinerator
in compliance with sections 3004 and 3005 of the Solid
Waste Disposal Act, in accordance with section 121(d)(3) of
CERCLA. Therefore, GAC permanently and significantly
reduces the mobility, toxicity and volume of hazardous
constituents. Morever, the potential inh~lation of
emissions from air stripping without off-gas treatment
presents a greater ris.k to the public health than GAC and
does not meet the permanency criteria under section 121 of
CERCLA.
-------
7.
Comment: The state has objected to the conclusion in the
Record of Decision that the ARARs for this operable unit
are the final or proposed MCLs established under the Safe
Drinking Water Act for all contaminants identified in south
Adams County drinking water. (See May 22, 1987 letter from
Thomas P. Looby to James Scherer, which is attached in
Appendix C).
Response: EPA's rationale for selecting MCLs as an ARAR
for this operable unit is set forth in the Record of
Decision document.
8.
Comment: The State has commented that insufficient
financing exists to complete the construction and operation
of the GAC treatment system.
Response: EPA is working closely with the State, the Army'
~
and SACWSD to identify sources of funding.
9.
Comment: The State has also commented that other ARARs
identified by the State of Colorado were not determined by
EPA to be ARARs for this remedial action.
Response: State ARARs are addressed in the Record of
Decision, including Appendix B.
-------
~
ATTACHMENT A
TO APPENDIX A
COMMUNITY RELATIONS ACTIVITIES CONDUCTED AT THE
ROCKY MOUNTAIN ARSENAL OFF-POST SITE
Community relations activities conducted at the Rocky Mountain Arsenal
Off-Post site from April 1985 through January 1987 are listed below.
o Public Affairs Task Group of Memorandum of Agreement (MOA) parties
is formed (August 1984).
o Tri-County Health Department followed up residential water sampling
with letters informing residents of sampling results after each
sampling event.
o EPA met with Colorad~ Citizen Action Network (CCAN) and Metropolitan
Organization for People (MOP} apout EPA's studies in south Adams,
County (Hay 1985).
o EPA attended public meetings held by the Citiiens Against
Contamination (CAC) on July 24 and November 25, 1985; and February
13, March 5, and May 22, 1986.
o EPA prepared a Fact Sheet that provided the public with a directory
of agencies and contacts for issues relating to the site (February
1986).
o EPA conducted discussions with local officials and area residents to
obtain first-hand information regarding community concerns about the
site (February-March 1986).
o EPA prepared and distributed widely a videotape that answered common
questions residents have had regarding the TCE in their water (April
1986).
o EPA prepared and distributed a Fact Sheet on RIfFS plans at the
site, others studies in progress in the area, major agencies
involved at the site, and the Superfund community relations program
(August 1986).
o EPA has responded to numerous citizen, vendor, and press inquiries
(Summer 1985 to present).
-------
o EPA prepared and distributed a Fact Sheet on the FS Report for the
First Operable Unit, other studies at the site, and ways citizens
can obtain 1urther information (December 1986).
o EPA held a public comment period on the remedial alternatives
proposed in the FS Report for the First Operable Unit (December 12,
1986 through January 7, 1987).
A-2
,
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ATTACHMENT B
TO APPENDIX A
RISK ASSESSMENT FOR THE VINYL CHLORIDE EMISSIONS
FROM AIR STRIPPING
The following risk assessment for vinyl chloride emissions from an air
stripper covers Occupational Safety and Health Administration (OSHA) and
American Conference of Governmental Industrial Hygienists (ACGIH) standards
and the 10-6 Cancer Assessment Group levels. In addition" as iden~ified
in Section 2.3.1 of the Feasibility Study Report, a National Emission
Standard for Hazardous Air Pollutants (NESHAPs) for certain industrial
facilities may be relevant and appropriate for such an air stripper.
The NESHAPs standard for emission f~om vinyl chloride plants (see I
40CFR61.63) is 10ppm, which is approximately equivalent to 21,000 ug/m3 a~'
25°C at 5,200 fe~t elevation. The stack exit concentration reported from
the air stripper is estimated to'range from 610 ug/m3 to 180 ug/m3,
depending on levels of vinyl chloride in the ground water. The stack exit
concentrations of vinyl chloride would be well below the NESHAP standard
for vinyl chloride plants.
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~(;@~~U@WG@~
Health and ErMronmental Science
CEmEnt ASSOCiatES. Incorporated
~tmMlOI"I8I Sou8I"1 sse K Stl'Mt PWt/
WIshr.;tOI, DC 20006 ~-BZB.asoo
From:
Michae1 J. Smith. COM/Denver
~~~hom&S Go10juch. ICF/C1ement
March 3. 1987
M.:,~
. . .'.-
" .,
. ,,-. .
To:
Date:
.... ,
.. '... ..
0. .. ....
..... '.'
!. J~"~'~
Project: RHA Off-Post RI/FS Site/First Operab1e Unit
Subject: Hea1th Risks Associated with Potentia1 Viny1
an Air Stripping Faci1ity .
Document Contr01 No: 198-RI 1-RT-DYGG-1
Ch10ride Emissions from
The Feasibi1ity Study (FS) for the first operab1e unit of the EPA's Rocky
Mountain Arsena1 (RMA) Off-Post RI/FS Site focuses on remediation of public
water su~~ly contamination in the RI/FS study area. One of the groundwater
treatment technologies under consideration for the South Adams County Hater
and Sanitation District (SACHSD) water supply could result in worker exposure
to volati1e organic com~ounds because emissions from the treatment units. if
uncontr011ed. wou1d contain the org~nic compounds stripped from the
contaminated water. The health risks associated with exposure of workers or'
nearby residents to v1ny1 ch10r1de. one of the compounds that cou1d .. .
potential1y be released at an SAOHSD air stripping faci1ity. are briefly
discussed be10w~
As an indication of p'aus1ble maximum exposure to on-site workers, Camp
Dresser & McKee estimated the concentration of vinyl ch10ride in off-gases
re1eased direct1y from the air stripping towers. Off-gas concentrations were
derived by assuming that viny1 ch10ride wou1d be present at 10 ~g/1iter or 3
~g/11ter in groundwater, that 2 air strip~ing towers would be used. and that
12 mi11ion gal10ns of contaminated groundwater would be treated per day.
Under these assumptions. off-gases re1eased direct1y from the towers would
contain I combined maximum v1ny1 ch10ride concentration of 610 ~g/m3 and
180 ~g/m3 for the 10 ~g/1iter and 3 ~g/1iter groundwater exposure
scenarios. respective1y. Viny1 ch10ride concentrations at 100 meters frm the
air stripping towers a1so were ca1cu1ated to provide a '.ss conservative
estimate of potentia1 worker exposure and p1ausib1e ..xi mum estimate of
potentia1 Ixposure of nearby residents. Ambi.nt concentrations of viny1
ch10ride at a distance Of 100 ..ters from the air stripping towers were
estimated at 0.155 ~g/mJ and 0.046 ~g/m3 for the 1O-~g/1iter and
3-~g/1iter groundwater exposure scenarios. respective1y.
The .ffects of viny1 ch10ride on both humans and experimenta1 animals are
described in the attached toxicity profi1e. The Occupationa1 Safety and
Hea1th Administration (OSHA) and the American Conference of Governmenta1
Industria' Hygienists (ACGIH). have recommended time-weighted average (THA)
occupationa' exposure 1imits of approximate1y 2.6 mg/m3 (2.600 ~g/m3)
-------
and 10 mg/m3 h'\OOO<~/m3"s ,respective1y. for airborne viny1 chloride in
the workp)ace. These va1ues are i"tended to protect the hea1th of workers
Ixposed B hours/day for a working 1ifetime to chemica1s in the workplace.
Although ACGIH vaJues are on1y recommended guidelines. OSHA THAs are legally
enforceab11 1imits.
According to EPA's system for characterization of the overa11 weight of
Ividence for carcinogenicity. vinyl chloride is c1assified in Group A. meaning
1t 1s a human carcinog.n based on Iv1dencl from Ipidemi010gic studies. A
cancer potency factor is ther.for. used to Istimate the potentia1 Ixcess
cancer risks associated with exposure to this compound1 The 951 upper-bound
cancer potency for viny1 ch10ride is 7.,.,0-6 (~g/m3)-. This va1ue
1s an Istimat. of the ,.C'SS ,anc.r risk assoc1at.d with continuous 3
'nha1ation. at a rate of 20 mJ/day. of ambi.nt a'r containing 1 ~g/m
viny1 chloride by a 70-kg person ov.r a 70-year 1ifetime.
For this ana1ysis. 1t '5 assumed that nearby residents could potentia11y
be exposed to viny1 ch10ride continuous1y for a 70-year 1ifetime or for a
2-year period. It is assumed that workers cou1d pottntia11y be .xposed to
viny1 ch10ride for 8 hours/day. 5 day/week. for 47 years (a working 1ifetime
constituting emp10yment from age 18 to 65) or for 2 years. The cumu1ative
dose received during either the 1ifetime or 2-year .xposure period was
therefore expressed as an average dai1y exposure prorated over a 70-ye.r
1ifetime. and the corresponding 1ifetime risk was ca1cu1ated accordingly.
This procedure is recommended in EPA's -Guide1ines for Carcinogen Risk
Assessment" (Federal Register 51:33998. September 24. 1986). Based on the
Ixposure assumptions noted. the prorated average dai1y .xposure for a 1ifetime
. worker at the air stripping faci1ity ~ould be a factor of approximate1y 0.16
times that of an individua1 exposed continuous1y for a 70-year 1ifetime to thd
same airborne concentration; for a 2-year worker this factor wou1d be 0.0068~' .
Upper 951 confidence 1imits on Istimated excess cancer risks associated
with inhalation exposure of workers to viny1 ch10ride at the air stripping
towers or at a distance of 100 meters and for residents at a distance of 100
meters were ca1cu1ated using the EPA-derived cancer potency factor for this
compound and the exposure assumptions noted above. These values are shown in
Exhibit 1 for the tower off-gas or ambient concentrations and exposure periods
considered. EPA encourages e1imination of cancer risks to individuals
resulting from exposure at a Superfund site where this is feasible. However,
according to agency p01icy. the total individua1 cancer risk resu1ting from
.xposures may range between 10-4 to 10-7 (1.... one excess cancer in every
10.000 and 10.000.000 individua1s. respectivl1y. exposed throughout their
1ifetime). Thus. an Ixcess Clncer risk of 10-~ 15 commonly used IS In
approximate guide1in. for determining an acc.ptab1e 1eve1 of ,.posure within
one or two orders of 8Ignitudt.
As shown 1n Exhibit 1, the 1ifetime ,.cess Clncer r1sks associated with
txposurl to Y1ny1 chloridl under the p1ausib11 8&ximum sc.nari0s considered
(worker Ixposurl at the air stripping towers) range from 9.10-6 to
7.10-4. For comparison. Ixposure to viny1 chloride for a working 1ifetime
(47 years) at 0.9 ~g/m3 or for 2 years at 20 ~g/m3 wou1d each be
associated with an .xcess Clncer risk of lr6. The air'stripping tower
off-gas concentrations of 610 and 180 ~g/m shown in Exhibit 1 Ire each
11ss than the OSHA Ind ACGIH workp1ace criteria of 2.6 Ind 10 mg/m3,
respective1y. . .
ClEmEnt AsSOciatES. Incorporated
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Lifetime excess cancer r;..~s ~;;ucia~~d with occupational or continuous
ambient Rxposure to vinyl chloride at concentrations that could potentially
occur at a distance of 100 meters from the air stripping towers are tess than
or equal to 10-6. under all exposure scenarios considered.
I
..
ClEmEnt AssociatES. Incorporated
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OHIBIT OJ
EXCESS CANCER RISKS ASSOCIATED WITH INHALATION
OF VINYL CHLORIDE EMISSIONS FROM THE
SACHSD AIR STRIPPING FACILITY
Excess Cancer Riska
Viny1 Ch10ride
Concentration
Lifetime Exposure
2-Ytlr Exposure
Occupationa1 Exposureb:
At lir stripping tower:
610 }lg/m3
180 }lg/m3
100 meters from tower:
0.155 }191m3
0.046 }lg/m3
Ambient Exposurec:
100 meters from tower:
0.155 }lg/m3
0.046 }lg/m3
7xl0-4 [A]
2116-4 [A]
2110-7 [A]
5x10-8 [A]
3x10-5 [A]
9x10-6 [A]
8110-9 [A]
2.10-9 [A]
h10-6 [A]
3.10-7 [A]
3xl0-8 [A]
9110-9 [A]
IViny1 chloride i.s classified in EPAIs weight-of-evidence for
carcinogenicity Group A, mean~ng it is considered I human carcinogen.
bAssumes exposure 8 hourslday, 5 days/week for I 47-year (working lifetime)
or I 2-year period.
cAssumes continuous exposure for a 70-year 1ifetime or for 2 years.
I
ClemEnt AssociatES. Incorporated
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VINYL cm.oRIDE
.
19854,))). On-aUc inhalatia'\"am oral studi- of ecp8ri1l8ntal animals ~
-------
involv~ the liver, 8pleen, kidneys, hematqloietic 8YSt8m, and skeletal
~ (EPA 1984a).
~CI'ri'~ Ut~J.::»
Inhalation eq:.:4N%'8S of rata, rabbits, and 11108 to vinyl chloride cUd not
1zx!uc8 tcat.t:lgcUc eff8Cts (EPA 1985a,b). Potantial eff8Cta on ~WtU>oc!IJctive
capacity have net been atudi8l1 (EPA 1985a,b).
K1rAGEmCIT'i
'lb8 DUtaqenic effects of vinyl chlorid8 haw b88n d8mc1nstnt8! in
1II8tabolicallyactivata:l syst8ms usinq ~, E. coli, yust, qum
cells of Dro8q:Ihilia, and aun.s. hamster V79 c:alls (EPA 1985a,b). Vinyl
chloride was effective in prcx!ucinq ~ damaqe in rat bane man"OW after
a D.1ltiple tDCpCSUre 1"8;ime (EPA 1985&,b). ~ aberrations in h\mIans
have yield8:1 inccnsistent results (EPA 19854,b).
CARCIN:XaEmCIT'i
,
..
'lb8 ability of vinyl chloride to act as a carcino;ren in the 1n:!ustrial
enviranment was readily 8Stablishe:J because of the "'-~'Ia&C rarity in tDCpOSec1
populations of the hepatic an;iosaro::mu with '-'hic:h it ia usocatea (IARC
1979). Vinyl chl0rid8 GpCI8Ur8 has also been ~lic:at8! in brain, lunq, am
h8mol~ietic c:anccs in humans (DR: 1979). An1mal st:ur::Ues in several
species support the firdinr;s of lIpidmioloqic:al studies. au-onic inhalation
and in;estion of vinyl chlarida has 1zw't~ C8nC8r in livv (liver
an;iOMrOCllllU an:I h8pa40--' 'ular carcincmu) an! oth8r tiau8s in rats am
1I1c8 (DR: 1979).
~CIf OF HEAI:IH ur~J.~
Jrplyinq DA'. c:rit8ria for 8Yaluatirq the ~ ~;ht of .vidence of
c:arc:incgenicity to humIIns, vinyl chloride has been classified in Grtup A,
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EPA (1984a) ~~rted ~ pot8ncies (~*) for uposure Dy iMalation
and in;eSticn to vinyl d'llorid8 in its Hu.lth Effects Ass-SNnt (REA) for
this c::ar;xan1. '1ha en. for 1Malatia\ is base a\ an inhalation bioassay 111
nts (Maltcni and. IafC11.in8 1975). Grcup8 of 64 to 96 Spraq\»-Dswley rats were
ecpoHd to varicus QQI~uL.cat.icr8 of vinyl d'1l0rid8 for 4 hcur8 a day, 5 c:1ays
a 1IIIIek, for 52 W88Jca, 8Z'IS th8 8UrVivars wre acrifiC81 attar 135 weks.
AnqiOMrCClllU, partiaWarly of th8 liwr, wre th8 1oMo-~inant tumors .
CIt88.rY8:!. '1ha 1imariz8cS 1Ult.i.8ta;8 ID58l was fi~ to th8 incid8uCes of
male an! fmale rata with any type of al~ t:urIIar (6/58, 10/59, 16/69,
22/59, an! 32/59 1n th8 0-, 50-, 250-, 500-, an:! 2,500 PPD dc88 c;rcaJp&,
r8Sp8Cti vely. '1ha 6,000- and 10, ()()O-ppD CJrCUI8 wre net incluc!8:1 in the firlal
fitted m:::dal because th8 tuIIm' inr:id8nca was 88icS ~ hav8 etf8CtiV8ly
plateaue::l at 51.7' an! 62.3'. USinq th8 linMr ncnt.hrMhold 1IICdal adcptad by
the EPA (198Ob), the data of Maltcni an! Iaf81Din8 (1975), an! int.ersp8cies
scalinq fac:t.ors, a human en. of 2.5x10-2 (Dq/)c;,lday)-l was calculata:l.
'!he en. for oral ccposure to vinyl chloride, as ~~~ L8:1 in the MEA for this
. c::ar;xan1, is based a\ a lc:n;J-t.em ~a\ Rudy 1n rata (Feron I
et ale 1981). Gra.1p& of male an:! f8Dllle wistar rata were 8Xp088:S tc'vinyl~'
. chloride via in;estian of 5X)lyvinyl d'1lorid8 ~r cantai.nin;r 8an8 unreac:ted
monaner. '!he dcses of vinyl d'lloride ~ were 0, 1.7, 5.0, am
14.1 m;I)cg,Ic:1ay. D:8inq was oant.ira.1ec1 for lif8tiD8s with tarminal sacrifices
at 135 weeks for males and at 144 W88Jcs for feales. A aignificant
dcse-relata:l incr8ase 1n th8 inr:id8nca of blpat.oc8llular carcinaDas am
h8patic angiCMrOClllU was CIt88.rY8:! 1n both mal8 8Z'IS feal8, with
angiC8a%"OClllaS '--;"Ig IIm"8 pNYalcrt with inc:ru.sini dc88s. 1M l:1nearized
D.1lti.staqe JIICd8l was fitt8S to th8 incid8nc8s of total ftaale rata with 1:1mr>n
(2/57, 26/58, 42/59, in th8 0-, 1.7-, 5.0-, and 14.1-sa;,/kq/day dc8e groups,
rupectiV8ly). 'Jh8 inr:id8nca of blpat-.llular carc1n::IIIa was net included 111
th8M talli88: it was .--' that rata bavin; bIpa~l1ular carc1n::IIIa also
hac1 blpatic 18:1p1utic ~- 1IIbic:t1 were includ8d 1n th8 talli8. In
addi tia\, th8 total IUIi:I8r of 8l"~1M 1. I:I8ari:I) tuIDor8 in th8 high dc8e c;rcup
was az:!:)itrarily ~X*t to CI18 1- than th8 total JI.IIi?8r of 8l"i1MJ!!I examined,
80 the data wculd fit th8 limar ncn-thr8hold 1IICdIIl U88S for 8St.1matiCl\ of
carcincqenic pat8'¥:y. USin; th8 data of. FC"cn 8t; ale (1981) an! intarspecies
-------
- .
CwI~ticn :in drlnki.nq watar ~1.~4in; to a 10-6 ~., lifetime cancer
risk is 0.015 ur;,Ilitar.* '1h8 OG .is 1"'" lS1tly r-""~9in; the cancer risk
8StJJrata tIu8! en the F8rcn 8t 81. (1981) 8b.x!y by t.akin; into a~ the
Dm'8 noent data by Til 8t 81. (1983) ~ 1a an 8Xt8nsia'\ of the earlier
Fccn 8t 81. (1981) wrk, bJt J.nclud.in; lClW8r dcMs.
. EPA (1985c) prcIIIJlgata! a drlnki.nq watar JICL of Z8r0, t--".. v1:1yl chloride
18 a buman c:arcinr:Ig8n. A drlnki.nq watar II:L of 0.001 m;llitar has b88n
~. r»ed (EPA 1985cS).
'1h8 EPA atfic. of Drinkin; Water d8Y8lcp811o-day hMlth 8dvisories (HAs) of
9.0 m;/litar for an 8dIJlt and 2.6 m;llitar for a chileS (EPA 1985&). 'lha HAs
were based en a 8Ubc:branic 8tUdy in Which v1nyl c:::hlorid8 was adm.in1st8red by
c;avage to male and f8lDl.le W1.star mta at dc8es of 31, 100 or 300 1IIJI)cq anca
daily, 6 days par W8k for 13 W88ks (Fccn 8t 81. 1975). S8Y8ral
hematoloqical, bioc:b8mical, an:S or;an wight valU8S wre significantly
diffennt in both mid- an:S high-G:88 81";'_1- ~r8cS to a::ntrols. '1M NOm.
in this stLJ:!y was id8ntifi8cS as 30 m;/1cI;J.
,
.
An adjust8:! ADI of 0.046 m;/liter for ncn:arcincqenic, effects was calculated
using an oml fMdin; 8tUdy in mts \lhich 4-t-rtec1 that a dc8e of
1.3 m;/1cI;/day ~~ liver lesions: a dcs8 of 0.13 m;/1cI;/day was identified
as a tQEL (Til et 81. 1983).
~ OF vnm. cm.am:E am'ERIA
EM c:arcinr:Ig8n cla8ificat.icn
Oral c:arc:1nag8nic pct8n:y tactar (en.)
Inbalaticn ~ pct8n:y factor (en.)
EM drlnki.nq wat.c' bMlth 81vi8aries (HA)
~ya:
Adult
aUleS
Grcup A
2.3 (m;/1cI;/day)-l
2.5xl0-2 (m;/1cI;/day)-l
9.0 m;/litar
2.6'Dg/liter
* This value was s~arized and included in the recommendations of the
-------
Final R1CL
Zero
0.001 m;/liter
,.. ~ JI:L
Drinkin; water CQa~ht..ation .
cc...~din; to 10-6 --
lifetU8 c:ancar risk
»Q: «X:lIIQlllal.caticn aucciata1 with
. 10-6 lifetU8 C:anc.r risk)
In;8st1on of watar anr:1 8qU&Uc
orqani8ZI8
In;8st1on of watar
0.01.5 ur;.Ilitar
2.0 u;Ilitar
2.0 u;/litar
~
~~.~ 1.GmC'l (EPA). 1980. AJd:)iC'lt Watar Quality
critaria for Vinyl ~orida. Office of Watar Watar R8;ulaticna and
Standa%ds, critaria and Standa%ds Division, Wuhin;tcn, D.C. Octcber
1980. EPA 440/5-80-078
~ ncuu:"';a~ NmC'i (EPA). 1984a. Health Effects
Ass---rt for Vinyl ~orida. Envira'lm8nt:al critaria and ~.-~t
Office. C1ncinnati, Chio. S8ptctI8r 1984. EPA 540/1-86-036
I
RbJ.;u;a~ 1.GmC'l (EPA). 1984b. p£. ,-
-------
KAUtNI, c., and u:F!K[NE, G. 1975. Carcincqenicity biousays vinyl
c:hlorid8. O-...nt Z'8Ulta. Ann. NY Acad. Bei. 246: 195-218
TIL, H.P., ~, H.R., and ~, V.J. 1983. Lifespan aral carcincqenicity
8t:udy of vinyl c:hlarlda in rata. Final RaIpot't. Civo Institut8 'IN:)
R8port No. V 83 285/29109
SUPERFUNP PUBLIC HEALTH EVALUATION MANUAL
EPA 540/1-86/060, October, 1986.
I
..
-------
ATTACHHENT C
TO APPENDIX A
ESTIHATED COSTS OF AIR STRIPPING
I
..
-------
CAMP DRESSER & McKEE INC
MEMORANDUM-
FROM:
John Hopkins - Denver
Stewart Abrams - Edison ~~
TO:
. DATE:
February 5, 1987
PROJECT:
EPA ~ontract No. 68-01-6939, RHA Off-rost RI/FS Site
SUBJECT:
Conceptual Sizings:
Vinyl Chloride Stripping
DOCUMENT CONTROL NO.:
198-FS2-10-DXTG-l
As you requested, we have analyzed a range of sizings to remove vinyl
chloride from a 12 mgd flowrate. We recommend that the flow be split, at a
minimum, into two separate parallel flows. Therefore, the sizings are
based on 6 mgd. We have evaluated two separate treatment objectives: 1)
0.1 mcgll, which roughly corresponds to the lowest practical analytical -6
detection limit, and 2) 0.015 mcgll, which roughly corresponds to the 10
lifetime cancer risk. Two raw water concentrations have been evaluated for
each scenario: 3 mcgll and 10 mcg/l: We have assumed that the background'
water quality presents no unusual interferences to the stripping process. .
The costs of the towers include clearwell, pumps, tower and internals, and
blowers. Design engineering is not included nor is the cost of a building
to house the facilities, access roads, or other indirect costs. Therefore,
for each case the following sizings and rough capital costs apply:
Case 1:
Raw water - 3.0 mcgll
Finished Water - 0.1 mcgll
At 6 mgd:
Tower diameter - 12 ft.
Packing height - 18 ft.
Air-to-water ratio - 20:1
Cost:
2 towers @ $401,000 each - $802,000
Case 2:
Raw water - 10 mcgll
Finished water. 0.1 mcg/l
At 6 mgd:
Tower diameter - 12 ft.
Packing height - 24 ft. ..
Air-to-water ratio - 20:1
Cost:
-------
CAMP DRESSER & McKEE INC
Memorandum
John Hopkins - De~ver
February 5. 1987
Page 2
Case 3:
Raw water . 3 mcg/l
Finished water. 0.015 mcg/l
At 6 mgd:
Tower diameter. 12 ft.
Packing height. 28 ft.
Air-to-water ratio. 20:1
Cost:
2 towers @ $481.000 each. $962.000
Case 4:
Raw water . 10 mcg/l
Finished water. 0.015 mcg/l
At 6 mgd:
Tower diameter. 12 ft.
Packing height. 33 ft.
Air-to-water ratio. 20:1
Cost:
2 towers @ $516.000 each. $ 1.032.000
In all cases. if the 12 mgd were treated in a single tower. we would .I
recommend an 18 foot diameter. Oth~~ise. packing heights and air-to-wat~r
ratios would remain the same. Costs would also be about the same
magnitude.
If you have any questions. or require further information. please call.
SA/ebe
cc:
S. Medlar
G. Kroll
B. Roberts
FUe
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APPENDIX B
APPLICABLE OR RELEVANT AND APPROPRIATE
STATE STANDARDS
-------
APPENDIX B
APPLICABLE OR -RELE.VANl' AND APPR)PRIATE STATE IIDJUIREMEm'S
The State of Colorado provided the Aqency with wa list of the
applicable or relevant and ap~qriate on-post and off-post standards,
requirenents, limitations or criteria [Wrequirenents or standardsW]
for the It>cky Moontain Arsenalw on January 8, 1987. The State anended
this list 00 March 17, 1987, to delete several requirenents and add
an additional requirenent. The State identified all applicable or relevant
and appropriate standards (ARARs) ( Inat ooly those that are Jll)re stringent
than similar federal provisions. J.f
The lv:jency has reviewed the State's sutmittal under the criteria of
Section 121 (d) (2) (A) (ii) of CERCIA, ..mich provides in pertinent part:
Wi th . respect to any hazardous substance, pollutant or ca1taminant
that will remain onsite, if . . . any pranulgated standard,
requirenent criteria, or limitation under a State enviraunental
or facility siti!1Q law that is more stringent than any Federal standard,
. requirement, criterIa" or limitation. .. is legally applicable
to the hazardous substance or pollutant or contaminant concerned ,
or is relevant and appropriate to the circumstances of the release
01' .threatened release of such hazardous substance or pollutant or
contaminant, the remedial action selected under sectioo 9604 . . .
shall require, at the CCltPletion of the remedial action, a level
or standard of control for such hazardous substance or pollutant
or contaminant which at least attains such legally applicable or
relevant and appropriate standard, requirement criteria or limitation."
(enphasis CM:!ded.)
1/
Althoogh the State prcposed ARARs for oo-post and off-post of the Rocky
Mountain Arsenal, this analysis 1s limited strictly to those requirenents
which are applicable or relevant and apprcpriate to this specific ~rable
uni t. 'Ibis analysis is not intended to apply to or establish ARARs for
the cmgoing RI/FS work currently being conducted by the ArrttJ at RMA, and
is not intended to establish any pt'eCedent for future renedial actions
cooducted oo-pcst or off~t. ARARs DUst be established on a site
specific basis.
If a State requ!reaent that is identified as applicable. or relevant and
appropriate in this Appendix B is DDre stringent than a Federal requirenent,
the State requirement is the applicable or relevant and appropriate
requirenent to be attained for this c:parable unit. If the State and
Federal requirenents are equivalent, either the State or the Federal
requirenent IDJSt be attained. If an applicable or relevant and apIropriate
Federal requirenent is more stringent than a State requirement, the
Federal requirenent is the applicable or relevant and apIropriate requirenent
-------
-2-
Section Ul(d) (2) (C) of CERCIA limits the applicability qf State
requirenents or sitirg laws which cC11ld effectively result in the statewide
prchibition of land disposal of hazardaJs substances, IDllutant, or
cootaninants, unless certain CXJ'1ditions are met. Since the prc:posed
dispcsition of waste generated by or associated with any of the remedial
action alternatives for this operable unit is not laoo disposal, Section
l2l(d)(2)(C) is not applicable, and was not considered by the Aqency in
reviewing the State's prc:posal.
. Section l2l(d)(4)(E) of CEICIA provides the k;Jency with discretion to
select a remedial action that does not attain an applicable or relevant and
apprcpriate State requirenent if the State has not coosistently applied
the requiresrent in similar ciramstances at other remedial actions. 'Ihe
Aqency has not invoked this discretionary waiver with respect to any of
the State's ~oposed ARMs. The Aqency has not made any deteminations,
however, as to whether or not the State has consistently applied the
requiresrents at other sites.
Applicable or relevant and apprcpriate State requireRents are
summarized in the attachment to this Appendix.2/ In the event
that EPA has detennined that a State requirenent is not applicable or
relevant and apprcpriate for this specitic cperable unit, an explanation
is provided.
I
2/ A requirenent is applicable if it woold apply to the remedial action
if the remedial action were undertaken C11tside of CERCIA authority.
A requiresrent is relevant and appropriate if, even thaJgh not applicable,
it is designed to apply to problems or situations sufficiently similar
to those encountered at the site that its applicatioo is apprcpriate.
Requirenents may be relevant and apprcpriate if they waJld be applicable
-------
~TI'A~~~ 'It) APp~'DrY p.
APPLICAPLF OP RnfVA~1T At-JD APPROPPI.aTE STATF ~.aNDAPJ"I~, PF'n'IPE""J:'NTS,
L~ITATIOOSJ MID CRI'T'F'PI.a FOP 'WE' FP.a. OF'F'-~ PII~ SITF PIPS'!' OP~APLF UNIT
I. General O::mnents
A. Enforcement Provisions
'!he State has listed numerous enforcement provisions as APAPS for
this operable unit. See e.g., C.P.S. Sections 30-20-113 (Enforcef"ent-Ch,n
Penalties): 30-20-114-rYiolation-Penalty): '5-15-110 (Site deemed public
nuisance - when): 25-15-211 (Violation-cri~inal Penalties): 25-15-21'
(Violation-Civil Penalties): 25-15-309 (Prohihited Acts-ntforcement):
25-15-309 (Civil Penalties): 25-15-310 (Criminal Penalties): 25-8-601
(Division to be notified of suspected violations and accidental dischar~s-
penalty): 25-8-605 (O!ase and Desist Orders): 25-8-606 (Clean-up Order) ~
25-8-607 (Pestraining Order and Injunction): 25-8-608 (Civil Penalties)~
25-8-609 (Criminal Pollution of State Waters-Penalty): 25-1-114 and 114.1
(unlawful to disobey public health laws and civil penalties:
25-1-107(x)(III) (E) (warrants for inspection): 25-7-115 (enforcement) ~
25-7-121 (injunctions): 25-7-122 (civil penalties): 25-12-]04
(actioo to abate) ~ 25-12-105 (violation of inj\l'1ction - ~nalty):
33-6-103 (prosecution of offenses): 33-6-104 (imposition of penalty-
procedures: 33-6-10" (suspensioo of license privileQes) ~ and 33-6-107
(licensing violations-penalties).
Such enforcement provisions are ~ot standards, ~ouirements, criteria cIr
,
limitations under State environmental or facility eitin9 laws t~at are
leQal1y applicable to the hazardous substances, ~llutants or oontaminants
of concern or relevant and appropriate under the circumstances of the
release or threatened release of such hazardous substance or ~llutant
or contaminant, as reauired by Section 12Hd)(2)(.a.)(H) of CFRCLA.
Rat~r, the provisions provide the mechanisms by which State reaulatory
agencies may enforce substantive environmental or facility sitinQ laws
which may be AA~Rs for a particular remedial actioo.
Section l2l(d)( 2)(~)( if) provides that selected rel"edial actions must
reauire, at the completion of remedial action, a level or standard of
control for hazardous substances or tOllutants or contaminants of concern
which at least attains legally applicable or relevant an~ appropriate
stardards, requirements, criteria or limitations. 'Ihe enforcement
~ovisions do not contain envira1mental or facility siting requirel!'erlts
which describe, speci fy, require or otherwise {rOVide for a degree of
cleanup which the remedy must at least attain, nor do they describe,
specify, require or otherwise provide for levels or standards of Ca1trol
(such as those contained in, but not limited to, anbient or chemical
specific requirements, locational requirements, or .performance desi9" or
other action-specific requirements) for the hazardbus substances or pollutants
or contaminants of c:a1cern for this operable unit.
'therefore, EPA has concluded that the enforcement provisions contained
in the State's January 8, 19R7 list of APAPs are not APARs for this
operable unit. M1ile the enforcement provisions are not ARARs under
section 121(d)( 2)( A)( H) of C'ERCLA, the State nevert~less may assert
such enforcement provisions to the extent provided for bv law, in instances
-------
ATI'AC'P.MENT TO APPENDIX B (Cont. ;
Pi4",:",' 2
B. Permitting RPauirements
'the State has listed 'several permittin9 reauirel"ents, or the information
submittals, notificatiat requirements, monitorin9, fees, data C'Ollection, "and
data reporting requirements contained within such perntittin9 reauirements,
as ARARs for this orerable unit. ~e e.g., C.R.S. Sections 30-20-102
(tJ'\lawful to o~rate site and facimy without certificate of desi~atiat) ~
3~2o-103 (application for certificate) ~ 25-15-'02 (application for certificate) ~
25-8-501 ( 3) and (5) (permits recruired for discharge of pollutants) ~
25-8-503( 1) (permits-when reauired and when ~ibited) ~ 25-8-502 (application-
definitiats-fees-water quality ca'ttrol fund): 25-7-114 (air pollution
emissioo notices and emission ~rmits~ and implementing reQUlation!ll. ~
also 6 CCR 1007-3 Part 100.
EPA is not determining at this time whether the selected remedy for this
operable unit is an oo-site or offsiteresponse actions. under Section
121(e) of CERCLA, no Federal, State or local J:ermit is reauired for the
portiat of any remedial actioo C'Onducted entirely on-site, where such rem!dial
action is selected and carried out in C'Ompliance with Section 121. Q,nversely,
permits will be obtained for any portion of relT'edial action conducted offsite.
Peoardless of whether the selected remedial action is characterized as an
at:site or offsite response, the substantive ~isions of applicable or
relevant and appropriate pemi t reauirements (for example, environmental
criteria under which a permit is reviewed, or nalitoring reauirements and
data collectiat reauirements to determine whet~r substantiw environmental
reauirements are being attained) are ARAPs. Substantive reauirenents QE!nerally
include, but are not !i",ited to, pranulaated standards, reouirements, criteri"a
or limitations under a State environmental or facility sitino law which
describe, specify, reauire or otherwise orovide for a decree of cleanup which
the remedy must at least attain, or which de!!Ct"ibe, specify, reauire or
otherwise provide for levels or standards of c:a1trol for the hazardous suhstances
or pollutants or contaminants of c:a1cem for this operable unit. The applicat:-le
or relevant and aporopriate substantive pemit reauirelrlents are discussed
below in section II, ~pecific Provisions.
I
.
Information submittals, notifications, fee provisions, and data reporting reauirements
contained in permit requirements are not substantive requirements of State
environmental or facility siting laws. While the Agency does not c:a1sider
such information stbnittals, notifications, fee ~isions, and data
reporting requirenents to be ARMs for this operable uni t, the Agency
will maintain close consultation with a~priate State re~sentatives
to ensure thllt the State is provided with all relevant tecmical data,
reports, notifications, and other informaticn necessary for effective
implementatia'1 of the renedy. In IIDst cases, this means that the State
will receive at least as much timely information, notice, and data as it
~ld if the reouirements were applicable or relevant and appropt'iate
mder Section 121(d)(2)(A)(U) ofoCDCLA. Also, as rreviously noted,
permits will be obtained for the portion of any remedial actiat c:a1duc:ted
offsite.
-------
ATrAOIMENT ro APmIDIX B (Cont.)
P.3
In the event that any hazardous substance or pollutant or contaminant is
transferred offsite (ran the treatment facility,. such hazardous substance
or pollutant or contaminant shall only be transferred to a facili ty which
is operating in carplianoe with section 3004 and 3005 of the Solid Waste
Disposal Act in accordance with Section 121(d) (3) of SARA, or equivalent
or Dl)re stringent State requirEllents.
c.
Legislative D!clarations and Definitions
Legislative declaration provisions generally do not contain substantive
requirements of State enviromental or facility siting laws pursuant to
Section 121(d) (2) (A) (ii) of CER:IA*, am are therefore not applicable or
relevant and app:-opriate requirements. 'Ihe Aqanc:y will maintain close
ca1Sultation with apprcpriate State representatives to ensure that State
concerns and legislative intent are addressed. In the event a legislative
declaration contained substantive requirenents, it wculd be evaluated to
detennine whether it is a relevant and apprq>riate requirement.
D!filiitional provisions generally cootain substantive requirements
or directly i.npcict the scope or applicability of other sutstantive .
requirements. Definitional provisions generally are oonsidered ARARs
for this operable unit unless otherwise noted.
D. Sccpe of Specific. Provisions Discussion
I
.
The Specific Provisions discussion which follows addresses only the
Colorado requirenents specifically listed by the State in its Jaruaty 8,
1987, and March 17, 1987, letters to EPA. Other requirements not
specifically listed by the State, bJt contained within the referenced
statutes or regulations have not been evaluated.
*Por purposes of Appemix B and this Attachment, substantive requirements
include, b1t are not limited to, prQ1l1lgated standards, requirements,
criteria, or limitations under a State enviromental or facility siting
law which describe, specify, require or otherwise provide for a degree of
c1earup Wiich the remedy for this qerable unit DUSt at least attain, or
which describe, specify, require or otherwise provide for levels or
standards of control for the hazardous substances, pollutants or oontaminants
of conoern for this operable unit. See Section l21(d) (2) (A) (ii) of
-------
.. .
.. ........ ~ . ..
:. . "" ~.
ATtACHMENT ro APPENDIX B (Cont.)
PAGE 4
II. SPECIFIC PROVISIONS
A. Colorado SOlid wastes Disposal Sites am Facilities Act, Sections
30-20-101 to 30-20-118, C.R.S. 1986.
- Not applicable or relevant am apprcpriate - Design, construction
am/or cperation of a solid waste disposal site are not cooterrp1ated
as potential remedies for this cperable 1.D'li t. If solid waste is
generated as part of the r~uedy (not. cootenplated OJrrently,) such
waste shall be disposed of at an approved solid waste disposal
site or facility in accordance with the requirements of the Act
and pertinent regulations.
B. Colorado SOlid Wastes Disposal Sites am Facilities Regulations
6 CCR 1007-2, sections 1.1 - 7.3.
- Not applicable or relevant and apprcpriate - Design, construction,
arxVor cperation of a solid waste disposal site are -not contenq;>lated .
as potential remedies for this cperable unit. If solid waste
is generated as part of the remedy (not cooteroplated currently,)
such waste shall be disposed of at; an approved solid waste disposal
site or facility in accordance with the requirerrents of the
Act and pertinent regulations.
I
C. Colorado Hazardous Waste Act, C.R.S. 55 25-15-101 to 313.
- ~plicab1e to the extent the selected alternative involves
the generation, transportation, treatment, or storage
of hazardcus wastes. The spent granular activated carbon fran
the G\C treatment system may cootain hazardous wastes regulated
under the Colorado Hazardcus waste Act and iDt;>lenenting regulations.
The selected remedy does not cooterrplate disposal of hazardous wastes.
- The following requirenents specifically listed by the State
are net ARARs, since. they are not substantive requirements of
State environnental or facility siting laws pursuant to section
121(d)(2)(A)(ii) of CERCLA: C.R.S 55 25-15-102, 103, 200.2, 208,
215, 301, 302(2)(3)(4), and 304.
D. Rules am Regulations Pertaining to SOlid and Hazardous Wastes,
Part 2, Requirenents for Siting of BazardaJS waste Disposal
Sites
- Not applicable or relevant am apprcpiate. The selected
remedy does not contenplate siting of a hazardcus waste disposal
-------
ATIAQiMENT TO APPENDIX B
(Cont. )
P.s
E. Colorado HazardOJs Waste Regulations, 6 CCR 1007-3, Parts 260
to 267, 99.and 100.
The selected alternative, granular activated carbon treatment of the
gramdwater with incineratioo of volatile organic canpounds adsorbed
on the carbon, may generate hazardous waste (hazardous waste adsorbed
in carbon) which may be stored temporarily or transported to an ap(roved
facili ty for incineration and regeneration of the carbon. The following
(rovisions are applicable to such hazardOJS wastes:
Part 260 - Hazardous Waste Management System: General
Part 261 - Identificatioo and Listing of HazardC1ls wastes
Part 262 - StaRiards Applicable to Generators of Hazardous Waste
Note: S~rt E, Special Conditions, International
Shipnents and Fa.IIDeI'S is not applicable or relevant
and appropriate. The selected remedy does not contenq;>late
such cirOJmStances.
Part 263 - Staroards Applicable to Transporters of Hazardous Waste.
Note: If hazardOJs waste is transported outside of the State
of Colorado, the requirenents of 40 CFR Part 263, or equivalent
or mre stringent State requirements, are applicable.
Part 264 - Staroards for OWners and Operators of Hazardous Waste
Treat:Dent, Storage and Disposal Facilities
- S~rts A-H are applicable
I
~ .
- S~rt I is applicable if the selected remedy
involves storage of hazardous wastes in containers
- S~rt J is applicable if the selected remedy
involves use of tanks to store hazardous wastes
- S~rt K is applicable if the selected remedy involves
the use of surface i.upoondrrents to store hazardous wastes
- Subpart L is applicable the selected remedy involves storage
of hazardous wastes in piles
- 5uq)art M is not !pplicable or relevant and appropriate
since lam treat:Dent of artf hazardous wastes is not contEllplated
. as part of the remedy for this c.p!rable- unit
- 8uq)art N is not applicable or relevant ~ apprcpriate
. since the remedy does not ccnteuplate disposal of hazard01S
wastes in a larx1f ill
- 5uq)art 0 is applicable in the event incineration of the
spent carbon occurs within the State. If incineration
of spent carbon occurs outside of the State of Colorado, the
requirements of 40 CFR Part 264, Subpart 0, or equivalent or
-------
ATI'AOiMENT TO APPENDIY E ( Cent )
P~C:F (.
- Appendices 1-6 are applicable to the extent they contain substantive
requirements.
The following requirements are not applicable or relevant and approf'll"iate:
Part 265 Interim Standards for Omers and Operators of Hazardous Waste
'Ireatment, Storage, and Disposal Facilities
- interim standards do not apply to new storage facilities: remedies
s~uld comply with the nDre stringent Part 264 standards as
these represent the u1 timate RCRA ccmp1 iance standards and are
consistent with CFRetA's 9C)als of loogter1\'l pr'Oteetioo o.f public
health and the environment.
Part 267 Interim Standards for OWners and Operators of New Pazardous
Waste Land Disposal Facilities
- remedy does not contemplate land disposal of hazardous waste
Part 99
Notification
- Although the Part 99 notification provisia1 is not a substantive
require~nt, the Agency will maintain close consultation with
appropriate State representatives to ensure that the State
receives timely notificatioo of hazardous waste activities in
ac:c:ordance wi th the terms 'of Part 9~.
I
..
Part 100 Permi t Reauirements
- See Section I(B), General COmnents, Permittino Reauirements.
!he substantive reauirements wi thin Part 100 are aDDlicab1e
or relevant and appropriate. 'It1e Agency will maintain close
consultation with appropriate State representatives to ensure
their catcems are addressed.
- Sections 100.13, 100.30, 100.31, 100.34, and 100.61(b) do not
cattain substantive lX'OVisions and are not APARs. Section
100.20 is not applicable or relevant and appropriate since an
interim status p!rmit is not contemplated as part of the remedy.
-Permits will be obtained for the portioo of the remedial action involvin9
any off-site hazardous waste activity.
-------
ATrAOiMENT TO APPENDIX B (Cont.)
PAGE 7
-' "
F. Colorado Water CUality Control Act, C.R.S. Sections 25-8-501 to
25-8-612
- Not applicable or: relevant and apprcpriate. No discharge of pollutants
throogh point sources or non-point sources to waters of the State
of Colorado is cootemplated as a remedy for this cperable unit. If
there is a discharge of pollutants into waters of the State resulting
fran the remedial action (not contetplated), such discharge a1ly
may occur in accordance with the requireuents of the Colorado Water
()Jali ty Control Act am pertinent regulations.
. G. State Discharge PeDDit SystEID Regulations,S CCR 1002-2, Sections 6.1.0
to 6.18
- Not applicable or relevant and apprcpriate. No discharge of pollutants
throogh point source to waters of the State of Colorado is contE!l1'plated
as a l:~::u.edy for this cperable unit. If such a discharge occurs or is
contemplated, these regulations are applicable or relevant and app:-cpriate.
See Section 1(8), General Caments, Pemitting Requirenents.
Effluent Limitations, 5 CCR 1002-3, Sections 10.1.1 to 10.1.7
H.
.
- Not applicable or relevant and apprcpriate. No discharge of
wastewater into State waters is contenplated as a remedy for this
cperable unit. If such a discharge occurs or is contE!l1'plated, these
effluent limitations are applicable-or relevant and appcopriate.
I
I. Sewage and Stonn Sewers, 5 CCR 1002-7, Sections 5.1 tQ 5.2
- Not applicable or relevant and apprcpriate. No discharge of wastewater
to stonn sewers or prchibited connections to storm sewers are contemplated
as a remedy for this c.perable uni t. If such a discharge occurs or is
contemplated, these provisions would be applicable or relevant and
apprcpriate.
.
J. Basic Starxiards and Methodologies,S CCR 1002-8, Sections 3.1.1 to
3.11.9
- Not applicable or relevant and apprcpriate. No discharge
to waters of the State is conteaplated under this cperable
unit, nor does this cperable unit address renediatioo of surface
water or the underlying aquifer within the EPA Off-Post RIIPS
site.
. IC. Site Applicatia1S for O:mestic Wastewater TreatDBnt Works,S CCR
1002-12, Sections 2.2.1 to 2.2.7
- Not applicable or. relevant and apprcpriate. No CXX1Struction
of danestic wastewater treat:De~t "Ow is conteq>lated as a
-------
.,.
A'ITAOiMENT oro APPENDIX 8 ( Cent. )
PAGF 8
t. .Q:Ilora~ Safe r,; :,1Id.I'!g Water Authorities - C.R.S. SS25-1-1C'7(x), (Y):
. 15-1-114 and 25-1-114.1
-Generally, not applicable or relevant and appropriate. 'the cited prnvision
are not substantive reauire~nts. 'Ihe '-Qency will consult with
appropriate State representatives regarding any notification reauirements
to ensure effective imple~ntation of the remedy. If substantive .
requirements are identified, they will be evaluated to determine whether
they are appl icable or relevant and apJropriate.
M. Cblorado Primary Drinking Water ~eQulations, 5 CCR 1003-1, Articles
. 1, 2, 4, 5, 6, 7, 8.
-Applicable or relevant and a~~iate to the drinking water that will
be suppl ied to the publ ic through the selected reII'edy, for contaminants
identified in the groundwater which supplies the South klarns Cbunty
Water and Sanitation District (WSA(WSDW) supply wells.
N. Cblondo Air (\Jali ty Control Pegulations
-'Ihe air stripping alternatives would involve emissions of pollutants to
the atmosphere. Fbr remedies that involve air stripping, the Colorado
.Air Ouality Control Pegulations may be applicable or relevant and appropriateo
Fugitive particulate emission re9U1ations may be applicable or relevant
and appropriate regardless of which remedy is selected. 'The regulations
are discussed below:
-CbmrYa1 Provisions ReQulation, 5 CCP. 1001-2 - applicable or relevant
and appropriate. .
~ulation No.1, 5 C'CP 10(\]-3, Emission O:x1tro1 Regulatia\!= for Particulatesv
smokes, carbon monoxide, and sulfur oxides.
I
.
a. Although no en'issions of these contaminants are c:cntemclated as part
of the operation of the remedy, fugitive particulates may he (Jenerated
during the cmstruction of the remarly. Section III(d), F\Jqitive
Particulate Emissions, is applicable if the jurisdictional ~reouisites
are satisfied, or relevant and appropriate if such prereauisites are
not met. If particulates, smokes, carl'On na'loxide, or sulfur oxide
are emitted as a result of cmstructino or implementing the re~
(not contemplated,) then other sections of R89ulation No. 1 addressing
these poll utants will be applicable or relevant and appropriate.
-Regulatim No.2, 5 CCR 1001-4, Obr anission PeQu!ations - Applicable
-Regulation No.3, 5 CCR 1001-5, Air O:x1taminant anissim Notices, Bttission
Permits and R!es, PSD Regulations.
a. See Sectia\ I(B), General Q:)m,.ents, Permittino ReOuirements. '!he substantive
reQuirements within the permit sectia\s are appliCable or relevant and
appropriate. 'I11e Agency will maintain close consultation with appropriate
State representatives to ensure their cCrtcerns are addressed.
b. '!he Prevention of significant deterioration (PSD) E'e9Ulations arE' not
applicable or relevant and appropriate. None of the remedies contemplat
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..
"1:'TA~ TO }'PPENDIX B (Cent.)
PAGE 9
c. AlthaJ~ the emissioo notices ~ovision is not an ARAR, the Aq3ncy
will maintain close consultation with appropriate State representatives
to ensure that the State receives timely notification.
d. The fee provisions are not ARARs.
-Regulation No.6, 5 OCR 1001-8, Part A, Sections I, III, IX, and XIII,
Part a, Sections I, II am IV, New ScAJrce PerfODDal1ce Standards
a. Not applicable or relevant and apl;ropriate. '1ba selected remedy
cooteraplated for this ~rable unit woo1d not involve facilities in
any of these categories.
-Regulation No.7, 5 ~ 1001-9, Volatile Organic ~
a. ~plicable or relevant and appt'opriate if the selected remedy would
involve the storage, transfer or disposal of volatile organics, petroleum
operations, use of solvents or cutback asphalt or surface coating
~rations.
-Regulation No.8, 5 ~ 1001-10, Control of Hazardous Air Pollutants,
a. Relevant and appropriate if the selected remedy involves emissions
of vinyl chloride or benzene to the atJIDsphere. .
I
..
-Ambient Air ()Jality Standards, 5 CCR 1001-14.
a. No emissions of pollutants for which ambient air quality standards
have been established are contenplated as part of the selected remedy
this operable unit. (If an air stripper is required for the treabtent of
vinyl chloride, small ancunts of vcx::s may be released to the atlOOSphere and
cootribute to ozone fomation. The ozone standard is relevant
and appt'opriate to the contenplated remedial action for this operable
unit if emissions £ran air stripping will cootribute to . .e foz:mation
of ozone. Also, the total suspended particulate (TSP) standard is relevant
am appropriate in the event fugitive particulate emissions result
£ran the constructioo of the contenplated renedy.)
o. Colorado Air ()Jality Ca1trol Act, Sections 25-7-101 to 25-7-505
-'!be specific I;rorisions identified by the State do not contain
substantive EeqU1reaents am are generally not applicable or relevant
and apl;ropriate. If substantive requirements are identified, such
requirements will be evaluated to detemine whether they apply.
-'!be AqenC'J will maintain close QOnSultation with apl;E'opiate State representatives
to emure that the State receives tiDe1y notificatioo .in accordance with
-------
ATI'AC"H."!E!n' 10 APPE1\TIX P (Cent.)
P"GF 10
-Section l~J, r.w.i~:!erators 'md <:pen Burning - Not applicable or relevant
and appropriate. ThE! activities reaulated by this provision are not
c:ontemplsste'i in the selected remedy for this operable unit. If these
activities occur (not contemplated) this section will be applicable.
-Section 25-7-] 14 ~ovides for emission r:ermits. See Section !(P), General
Q:)lTITIents, Permittino Reauirements. '!'he substantiw reauirements of this
section are applicable or relevant and apPE'Opriate. 'I'he AQenCY will
maintain close consultation with appropriate State re~sentatives
to ensure their c:a1c:erns are addressed.
-Sections 25-7-501, 502, and 504. Not applicable or relevant and appropriateo
None of the remedies contemplated for this operable mit involve asbestos
c:a1trol.
P. COlorado Noise Abatement Statute, Sections 25-12-101 to 25-12-108
-Sections 25-12-102 (definitions) and 25-12-103 (Maximum Permissible
Noise Levels) are applicable requirements or relevant and appropriate
requirements. The other specifically cited provisions do not
contain substantive requirements and are not applicable or relevant
and a~opriate.
o. Wildlife, C.R.S. Sections 33-1-101 to 33-1-120
-Section 33-1-101 (sf'l:)rt title) does not ccntain substantive requirements
. and is not applicable or relevant and apPE'C)priate. I
-Section 33-1-102 (definitions) ~s applicable or relevant and appropdate.
-Section 33-1-1n6 (managelflent) is applicable if any of t~ selected
remedies involve the taking, possession, transJ:Qrtation, exportation,
shipnent, removal, capture or destruction of wildlife which aprear
on the State's list of endanoered or threatened species. It should
be noted that none of the proposed altematives c:a1template any of
the above-listed activivites for wildlife.
-See Section I(S), General ():)nm!F'ts, PeE'1"ittinq Peauirments. '!he Aoencv
will maintain close consultation with ap~ooriate State representatives
to ensure the ir concems are addressed.
R.. Wildlife Ehforc:ement and Penalties, C.R.S~ ~5 33-6-101 to 33-6-130.
- Generally, the specifically eited PE'Ovisions are not applicable or
relevant and appropriate. See discussion on Ehforcement Provisions,
p.l of this Attachment. SeCtions 33-6-109 (wildlife - 111e9al possession),
33-6-114 (transportation, importation, exportation and release of
wildlife), and 33-6-120 (hunting, trapping or fishing .out of season
or in a elosed area) are applicable or relevant and appropriate
to the extent they cattain sut;>stantive requirements. It should be
noted that the selected r~l.edv does notccntemplate any activities
-------
ATI'AaiMEm' 10 ~PPENr'IX B (I"bnt.)
PAGF 11
- See Section I{B), General (b.r~.,;:;S, P<2rmittin9 Peauirements. 'The Agency
will maintain close consultation with ap~~iate State representatives
to ensure their exnc:erns are addressed.
s.
General Provisions of the Division of Wildlife Reoulations, 2 CCP 4n~-o,
Article II. .
- ~ Sectim ICB), General CDm8Its, Permitting Pequirements.
.- Substantive reouirements CD1tained within these regulations are
applicable or relevant and appro~iate. 'the Agency will maintain
close consultatim with appropriate State re~sentatives to ensure
their exnc:ems are addressed. 'the selected remedy does not contemplate
any activitiesdesc:ribed by or prohibited by these reQUIations.
T.
'!he Water Well and Punp Installation COntractors ~, C.P.S. ~( 37-91-10]
to 37-91-112
- Generally, the Act does not cmtain substantive reauirements and is not
applicable or relevant and appropriate. Section 37-91-110 (basic
standards and minimum standards) cmtains substantive reauirements and
is applicable or relevant and appropriate to puI7'p installation. The
selected remedy does not cmtemplate construction of water wells.
- See Section I{~), General ():)nments,' Permittina Reauirements.
The Agency will maintain close consultation with appropriate State
representatives to' ensure their cmc:erns are addressed.
I
..
u.
water Well and Pump Installation contractors Peculations. 2 CCR 402-2
- ~ Section ICP), General Cbmnents, Pemitting Feauirements.
- '!he substantive reauirements contained within the re9Ulations are
appl,icable or relevant and ap~opriate to pump installation. The
selected rel1'edy does not contemplate construction of water wells.
The Agency will maintain close consultation with ap~priate State
re~esentati ves to ensure their concerns are addressed.
v.
Historical, Prehistorical and Archaeological Resources Act,
C.R.S. 5S24-So-401 et seq.
- Appl icable or relevant and appc"O~iate if the eelected remedy involves
the inftstigation, excavation, gathering, or rem:wal from the natural
state of any historical, prehistorical and archaeological resources
within the State.
- See Sectim ICB), General Q)I\...ents, Permitting Requirements.
The Agency will maintain close consultation with. appt"O~iate State
-------
.
APPENDIX C
STATE OF COLORADO AND SACVSD
CONCURRENCES VITO REMEDY
-------
.
STATE OF COLORJ\DO
COLORAOO OEPARTMENT Of HEALTH
/.'~
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4210 £1M 1 Hh Avenue
Oenve', Colorado 80220
Phone ()031 320.8333
. .
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Ro. Ron'.'
<;0'" '",)'
May 22. 1987
Thom., .,~ \''''''0''
IlI!c ...". D"",lul
Mr. 3ames Scherer
Rerional Adminiatrator
U.S. Environmental P~otection Arency
Rerion VIII
One Denver Place .
999 18th Street. Suite 500
Denver. Colorado 80202-2405
Re: EPA's AHA Off-Post First Operable Unit Approved Final Draft Record of
Decision (ROD) - South Adams County Drinkinr Water Treatment System
De.r ~er:
The State of Cplorado has review~d the May 14, 1987 Approved Final Drafl. ROD
for EPA's AHA Off-Post First Operable Unit. The State concurs with the.
selection of a rranular activated carbon (GAC) water treatment system as the
appropriate remedy for treatment of the contaminated rround water within the
EPA Off-Post RIfFS site prior to its use as drinking water by customers of the
South Adams County Water and Sanitation District (SACWSD).
While the State concurs with the selection of the GAC water treatment system
as the permanent remedy, our concurrence with the ROD is conditioned upon the
following:
1)
To date, insufficient financing exists to complete the construction
and operation of the GAC treatment system. Ther~~o~, it may be
necessary to utilize Hazardous Substance Response.'und money to
implement the final remedy. .However. the U.S. Army has been
identified as at 1east one party responsible for the contamination of
the drinking water supply. An investiration of other potentially
responsible parties (PRPs) ia in progress. Given that liability
under CERCLA is joint and several, the State's position is that the
identified responsible party(s) should provide the full costs of
implementing the permanent remedy, including operation and
maintenance costs.
In the event Fund money is utilized to implement the remedy, CERCLA
Section 104(c)(3) requires that the State enter into a contract or
cooperative agreement with the President providing adequate
-------
..
capital costs and all ~uture costs for operation and maintenance f~r
the expected life of the remedial action. However. pursuant to the
current State Superfund Act, Section 25-16-101, !! seQ.. C.R.S.,
State cannot make such assurances unless the site has been listed
the NQtional Priorities List (NPL). See Section 25-16-104.6 (2)(b).
At this time. neither the Rocky Mountain Arsenal nor EPA's RMA
Off-Post RI/FS site has been finally listed on the NPL.
Section 25-16-103(2) currently states that, "any State matching
payment required by a cooperative a,reement entered into pursuant to.
this section must be appr9ved by the ,eneral assembly acting by
bill." For these reasons, the State cannot .ake the 104(c)(3) 10~
cost assurance for construction of the permanent treatment plant, or
the assurance for all future operation and maintenance costs, at this
time.
2)
The State strongly objects to the conclusion in the ROD that the
applicable or relevant and appropriate requirements (ARARa) for this
operable unit are the 1inal or proposed Maximum Contaminant Levels
(MeLs) established under the Safe Drinking Water Act for all
contaminants identified in South Adams County drinking water. This
conclusion deviates from the Section l2l(d) Superfund Amendments and
Reauthorization Act (SARA) provision that the "remedial action
require a level or standard of control which at least attains Maximum
Contaminant Level Goals,(HeLas) established under the Safe Drirkinr
Water Act. . .tt .,
.
This. conclusion also deviates from the March 27, 1987 letter to Ert
Administrator Lee Thomas from the conferees involved in the CERe
reauthorization process. The letter was written "to advise you ( .
Thomas) of the requirements of Section 121 [of SARA) and the intent
behind them, . . .tt The letter also states that, tt(t]he specific
reference to MeLG's in the law makes it clear that these particular
standards, where they are more stringent than the comparable MeL's,
are the primary standards under the Safe Drinkin, Water Act that must
be attained bv ~~~~rfund cleanups 01 1T0undwater, . . ." The source
of SACWSD's drinkin, water is ,roundwater. Therefore, pursuant to
statutory requirement, unless the EPA determines that compliance with
MeLGs is technically impracticable from an en,ineering perspective.
MeLGs are the ARARs and must be attained. Section 12l(d)(4)(C). SARA.
As you are aware, MeLs are often established based upon the analytic
detection limits rather than on health based criteria. While the
State does not a,ree with the use of MeL. as ARARs, if MeLs are to be
used as ARARs, a safety factor must be incorporated which
approximates the 10-6 Cancer Assessment Group (CAG) cancer risk
value. For example, with trichloroethyle~e (TeE). one major
contaminant of concern at this operable unit, the 10-6 CAG number is
approximately 2 ug/l lower that the MeL. Therefore. a criteria that
incorporates an operational safety factor based upon a health related
-------
..
.
The EPA has determlned that other applicable or relevant and
appropriate standards, requirements, criteria or limitations (ARARs)
identified by the State of Colorado are not applicable or relevant
and appropriate tothia remedial action. There are many instances
where. the State disagrees with this determination.
To expedite implementation of the remedy for this operable unit, the State
concurs with the selection of the GAC water treatment system. However, we
feel it is necessary to meet with you to discuss and attempt to resolve the
issues outlined above at your earliest convenience. The State looks forward
to working closely with you to complete construction of the SACWSD permanent
water treatment system to protect the health and welfare of the citizens of
Colorado.
Sincerely,
~~
Thomas P. Looby
Assistant Director
Colorado Department
of Heal th
TPL/CS:me
I
cc:
Howard Kenison, Deputy Attorney General
Robert Lawrence, U.S. EPA
Larry Ford, SACWSD
Dave Brown, Esq.
Citizens Against Contamination
Senator Strickland
Senator Martinez
Representative Blesdoe
Representative Reeser"
Representative Hume
-------
c
.
.'
~~~~ C~~Tr /,,- v Coc.; C
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SANITATIO~ ~'\
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S595 EAST 70TH AVENUE
COMMERCE CITY, COLORADO 80022
TELEPHONE 303 288.2646
May 18, 1987
Mr. Robert L. Duprey
u.s. ENVIRONMENTAL PROTECTION AGENCY
Region VIII
999 Eighteenth street, suite 500
Denver, CO 80202-2405
BY HAND-DELIVERY
RE:
Final Draft Record of Decision ("ROD") for
First Operable Unit, EPA's RMA Off-Post RI-FS Site:
Document No. 198-FS2-RT-ENBC-1
Dear Mr. Duprey:
South Adams County Water and sanitation District has been
consulted by EPA with regard to the above-referenced ROD. Now
that the ROD has been reviewed by the District' 5 staff I and
consul tants, I am authorized by the Board of Directors of' the
District to inform you .that the District concurs with the
selected remedy set forth in the ROD.
We look forward to working closely with EPA in implementing this
next, and most important, milestone for the protection of our
customers.
Sincerely,
SOUTH ADAMS COUNTY WATER
AND SANITATION DISTRICT
- .' .~. .
By: "/. >" .' --/; .6:,~.1't.
Jean Klein, President
cc:
'/'
"Mr. Connally Mears
Hon. Hank Brown
patricia L. Bohm, Esq.
Mr. Randall J. Krueger
Lysle R. Dirrim, Esq.
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.
.
APPENDIX D
INDEX TO THE ADMINISTRATIVE RECORD
-------
. Pace No.
1
DOCUHENT DoCUHINT
DATI TYPS
12/19/83 REPORT
~
,..
APPENDIX 0
INDIX TO ADHINISTRATIVE RICORD
4 JUNI 1987
ISSUED
BY
DOCUHINT TITLK
OR DISCRIPTION
03/14/84 HRS PACIAGI 161
161
10/19/84 PLAN
04/23/86 PLAN
05/07/86 LITTIRS
05/15/85 LITTIR
05/15/85 LITTIR
05/31/85 PLAN
PRELIHINARY ASSESSHENT REPORT SOUTH ADAHS COUNTY WATIR AND
SANITATION DISTRICT COHHIRCI CITY, CO
IPA HAZARD RANIING SYSTIH fORHS fOR ROCIY MOUNTAIN ARSINAL
IXCLUDING BASIN' '
COHHUNITY RELATIONS PLAN TO ROCKY MOUNTAIN ARSINAL 0" POST
CONTAMINATION ASSISSHENT
DRAfT WORI PLAN HIHORANDUH RI/'S ROCIY HOUNTAIN ARSINAL -
0" SITI ADAHS COUNTY,' COLORADO
TRANSHITTAL 0' DRA'T WORI PLAN HIHORANDUH TO INTIRISTID
PARTIES rOR COHHINT
COHHENTS ON DRA'T WORI PLAN HEHORANDUH
COHHENTS ON DRA'T WORK PLAN HIHORANDUH
'INAL WORK PLAN HEHORANDUM RI/'S ROCIY HOUNTAIN ARSINAL
ADAMS COUNTY, COLORADO
GUIDANCI ON 'IASIBILITY STUDIIS UNDIR CERCLA OSWIR 9355.0-5C
GUIDANCI ON RIHIDIAL INVISTIGATIONS UNDIR CIRCLA OSWIR
9365.0-6B
WATIR AND WASTIWATIR SYSTIH MASTIR PLAN UPDATI , SYSTIH
DIVILOPHINT 'liS
DRA'T WORI PLAN 'OR ROCIY HOUNTAIN ARSINAL IPA O'f-POST
RI/fS AND OVIRSIGHT ACTIVITIES COLORADO
RIPORT 0' SAHPLING ACTIVITIIS MILT ADAHS, INC. OIL AND
SOLVINT PROCISSING CO. COHHIRCI CITY CO
STAT I COHHINTS ON DRAfT WORI PLAN 'OR RI/.S IN RHA O"-POST
STUDY ARIA
T. GILHIR/SACWASD SACWASD COHMINTS ON DRA'T WORK PLAN 'OR RHA O"-POST RI'S
CDH 'INAL WORK PLAN 'OR ROCIY HOUNTAIN ARSINAL IPA O"-POST
RI/'S AND OVERSIGHT ACTIVITIS COLORADO
RIPORT 0' ANALYTICAL RISULTS AT SOUTH ADAMS COUNTY WATIR AND
SANITATION DISTRICT, COHHIRCI CITY, CO
CDH RIH II HIALTH AND SA'ITY ASSURANCI HANUAL
G. BROITHAN/CDOH TO LITTIR RIQUIRING SACWASD TO TAil ACTION ON TCI CONTAMINATION
L. 'ORD/SACWASD
161
CDH
BPA
COlI
COlI
C. HAHN/SHILL
HRS/SACWASD
COlI
06/15/86 GUIDANCI DOC IPA
06/15/85 GUIDANCI DOC IPA
07/15/86 BIPORT
08/06/85 DRA'T PLAN
08/13/86 RIPORT
08/26/86 LlTUB
08/26/85 LlTUB
09/09/86 PLAN
09/23/86 RIPORT
11/01/85 PLAN
11/06/86 LITTIR
12/18/85 RIPORT
01/08/86 REPORT
01/12/86 HIHO
01/17/86 RIPORT
01/28/86 RIPOBT
02/03/86 DATA
02/11/86 RIPORT
02/13/86 'ACT SHIIT
SACWASD/JU
COlI
161
T. LOOBY /CooH
161
TAT
CDH/CLIMINT
CDH
'INAL SITI INSPECTION AND ANALYTICAL RISULTS REPORT
STAPLETON AIRPORT - .SAND CREEl DENVER, COLORADO
PHASE IA 'IELD SAHPLING RIPORT IN THI ROCIY HOUNTAIN ARSINAL
EPA O"-POST REGION
PRELIHINARY IVALUATION 0' INTIRIH TRBATHINT ALTIRNATIVIS
PRILIHINARY RISI ASSISSHINT 0' THI SOUTH ADAMS COUNTY WATER
AND SANITATION DISTRICT WATIR DISTRIBUTION SYSTIH
PHASI IB 'IILD SAHPLING RIPORT 'OR THI ROCIY HOoNTAIN
ARSBNAL IPA O"-POST RI/,S ARIA
BORING LOGS AND WATER LEVIL HIASUREHINTS 'ROH THI SAND CREII
OIL PLUHB INVESTIGATION
ANALYTICAL RESULTS REPORT 'OR LAND'ILL, INC. COHHIRCI CITY,
CO
SUPER'UND PROGRAH 'ACT ~H&lT - ROCIY HOUNTAIN ARSBNAL
O"-POST SITI COHHIRCI C1TY, CO
IPA/INICHOTIC
161
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Pa.re No.
2
DOCUHENT DOCUHINT ISSUID
DATE TYPI BY
03/01/86 PLAN IPA
03/05/86 LITTER R. LAHH/CO TO L.
THOIUS/IPA
03/06/88 ADVISORY CDOK
03/18/86 AORIIHINT IPA , AMY
03/31/86 LITTIR L. THOHAS/IPA TO R.
LAM/CO
04/04/86 PLAN COlI
04/17/86 PLAN COlI
04/17/86 RIPORT CDH/CLIII8liT
04/23/86 RIPORT III
OS/21/86 HIIIO T. FIILDS/EPA TO J.
PORTIR/IPA
OS/28/86 RIPORT SACNASD/JM
06/01/86 HDO T. fIELDS/IPA TO J.
PORTIR/IPA
06/11/86 RIPORT COlI
06/24/86 RIPORT III
07/22/86 RIPORT III
07/22/86 HDO R. DUPRIY/IPA TO J.
WILLS/iPA
07/22/86 HIIIO J. WILLS/IPA TO J.
PORTIR/IPA
07/31/86 LlTTIR J. WILLS/IPA TO L.
WALlIR/ARHY
08/01/86 DATA SACWASD/HRS
08/01/86 DATA ARMY/ISI/BBASCO
08/14/86 PLAN IPA
08/15/86 HEHOS/DATA CDH/CCJ
08/15/86 fACT S811T EPA
09/01/86 DATA UE
/03/86 HEHO R. DUPREY/EPA 10
HOA PART liS
APPENDIX D
INDIX TO ADHINISTRATIVE RECORD
4 JONI 1987 .
OOCUHENT TITLI
OR DESCRIPTION
\
ROCKY HOUNTAIN ARSENAL PUBLIC AFFAIRS PLAN 1986 - 1990
LETTER REOARDINO USI 0' ARHY fUNDS AND SUGGISTION TO SIT
ASIDI THI SEARCH fOR OTHER CONTAHINATION SOURCIS
STAT I OF COLORADO HIALTH ADVISORY ON SACWASD DRINIING WATIR
AGREIHENT BITWIIN US IPA AND DOA RIGARDING 'I HILLION rOR
TIHPORARY TRIATHINT SYSTIH fOR SACWASD
LITTIR RIOARDINO EPA SIARCH rOR OTHIR TCI SOURCIS
fINAL SAHPLING AND ANALYSIS PLAN fOR ROCIY HOUNTAIN ARSINAL
IPA Ofr-POST RI/fS, COLORADO VOLUHES I , II
fINAL QUALITY ASSURANCI PROJICT PLAN RI/fS IPA Off-POST SITI
ROCKY HOUNTAIN ARSINAL ADAHS COUNTY, COLORADO
PRILIHINARY RISI ASSISSHINT Of THI SOOTH ADAHS COONTY WATIR
AND SANITATION DISTRICT WATER DISTRIBUTION SYSTIH
ANALYTICAL RESULTS RIPORT DENVER ENGINIIRING OPIRATIONS
CINTER DEN VIR BULl HAIL fACILITY
IXEHPTION fOR $1 HILLION ~IHIT AND CIILINO INCRIASI fOR
SACWASD TEHPORARY TRIATHINT SYSTEH
TREATABILITY/fEASIBILITY STUDY fOR DISTRICT WATIR QOALITY
IHPROVEHENT
REGION VIII REQUEST fOR CIILINO INCREASI fOR SACWASD RIHOVAL
ACTION HEHORANDUH ADDINDUH
PHASI IC fIILD SAHPLING REPORT fOR THI ROCIY HOONTAIN
ARSINAL EPA orf-POST RI/fS AREA
SOUTH ADAHS COUNTY SOIL GAS SURVIY INTERPRITATIVI RIPORT
SOUTH ADAHS COUNTY, COLORADO
ANALYTICAL RESULTS RIPORT rOR NINI SITIS IN SOOTH ADAHS
COUNTY, COLORADO .
REQUEST fOR SIX HONTH TIHI EXIHPTION FOR CONTINUATION OF
REHOVAL ACTIVITIES AT SACNASD
CIILINO INCREASI REQUEST fOR SACWASD REHOVAL ACTION
REQOIST fOR fONDINO fOR PIRHANENT TRIATHENT SYSTEH
RISULTS Of WATER LEVEL, WATIR QUALITY, AND HYDROGEOLOGIC
INVESTIGATIONS
RESULTS 0' DRILLING, WATER LEVEL HONITORING, WATER AND SOIL
SAHPLING IN RMA WIST TIIR SICTIONS
DRAfT COHHlINITY RELATIONS PLAN ROCKY HOUNTAIN ARSENAL
OFf-SITI STlIDUS
DATA VALIDATION REPORTS AND DATA USABILITY SUHHARIES fOR
CONTRACT LABORATORY PROORAH ANALYSIS RISULTS
SUPIRfUND PROGRAH fACT.. SHilT - ROCKY HOUNTAIN ARSENAL
OFF-POST SITI COHHERCE ~Y, CO
BORINO LOGS, WILL COHPLITION DIAGRAMS, AND SURVEY DATA rOR
WILLS INSTALLED BY FIT SOUTH 0' 56TH ST
ARHY - IPA AGRE 10 1RANSFER $6 HILLiON rOR PERHANENT
TRIAT"IN1 SYSTE SACHASD
....
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Pale No.
3
DOCUHINT DOCUHINT
DATI TYPI
10/09/86 REPORT
ISSUID
BY
SACWASD/B6Y
10/16/86 GUIDANCE DOC EPA
10/20/86 DRAfT REPORT CD"
10/21/88 DRAfT RIPORT CD!
10/28/86 LETTiR
11/04/88 LITTIR
11/06/86 LITTIR
11/08/88 LlTTIR
11/07/86 LETTIR
ATSDR
T. LOOBY /CooH
,
SACWASD/HR8
R. DUPREY/EPA TO T.
LOOBY/COOH
SACWASD/B6V
12/08/86 fINAL REPORT CD"
12/08/86 fINAL ,REPORT CD"
12/10/88 REfERINCE CD!
12/10/86 MOTICI BPA
12/1,1/86 MOTICI
EP'
12/12/86 TELEPHONE J.CROWE
12/16/86 TILEPHONE HRS.LONG
12/16/88 fACT SHIIT. IPA
12/24/86 GUIDANCE DOC IPA
12/29/86 LETTER
12/31/86 LITTIR
01/06/87 LITTER
01/06/87 LITTER
01/06/87 LITTIR
01/07/87 LITTER
01/07/87 LITTER
01/08/87 LlTTIR
01/09/87 LITTIR
01/21/87 LETTER
SACWASD/BIV
CITIZENS AGAIMST
CONTAHINATION
SACWASD
SCHOOL DISTRICT 14
TRI-COUNTY HEALTH
DEPARTHINT
HRO
&ARLIN/COOH
T. LOOBY /COOH
CITY Of COMHERCE
CITY
ADAHS COUNTY
COMMISSIONERS
.
p
APPENDIX 0 '
INDEX TO ADHINISTRATIVI RiCORD
4 JUNE 1987
DOCUHENT TITLI
OR DESCRIPTION
DETAILED ANALYSIS Of ALTERNATIVES fOR ORGANIC CONTAHINANT
RiHOVAL
SUPERfUND PUBLIC HEALTH IVALUATION MANUAL EPA 640/1-86/060
MOA REVIEW DRAfT RiMEDIAL INVESTIGATION fiRST OPERABLE UNIT
ROCIY MOUNTAIN ARSENAL Off-POST RI/fS SITE
MOA REVIEW DRAfT fIRST OPERABLE UNIT ROCIY HOUNTAIN ARSENAL
orf-POST RI/fS SITE
REQUIST fOR ATSDR ASSISTANCE IN REVIEW Of fIRST OPIRABLE
UNIT RI AND fS DOCUMENTS
COMMENTS ON MOA REVIEW DRAfTS Of fIRST OPERABLE UNIT
REMEDIAL INVESTIGATION AND fEASIBILITY STUDY DOCUMENTS
SACWASD COMMINTS ON HOA REVIEW DRAfT REHIDIAL INVISTIGATION
REPORT
RKQUIST fOR STATI IDENTIfICATION Of ARAR.S
COHHENTS ON HOA REVIEW DRAfT fIRST OPERABLE UNIT flASIBILITY
STUDY
RiHEDIAL INVESTIGATIDN fIRST OPERABLE UNIT ROCIY HOUNTAIN
ARSENAL Off-POST RI/fS 81TE
fEASIBILITY STUDY fIRST OPIRABLI UNIT ROCIY HOUNTAIN ARSINAL
Off-POST RI/fS SITI
REfERENCE LIST USIO IN PREPARATION Of fIRST OPERABLE UNIT RI
AND fS REPORTS
CERTIfICATION Of OffICIAL NOTICE Of PUBLIC COMHENT PERIOD ON
fIRST OPERABLE UNIT fS REPORT - DENVER POST
CERTIfICATION or OffICIAL NOTICE Of PUBLIC COMHENT PERIOD ON
fIRST OPERABLE UNIT FS REPORT - COMMERCI CITY SENTINEL
COMMENTS ON fINAL FIRST OPERABLE UNIT RI AND fS DOCUHENTS
COHHENTS ON fiNAL fIRST OPIRABLE UNIT RI AND fS DOCUMENTS
SUPERfUND PROGRAM fACT SHEET - ROCIY MOUNTAIN ARSENAL
OFF-POST SITE COHMERCE CITY, CO
INTERIM GUIDANCI ON SUPERfUND SELECTION Of REHIDY OSWER
9366.0-19
COHHENTS ON fINAL fIRST OPERABLE UNIT RI AND FS DOCUHENTS
COMHENTS ON fINAL fIRST OPERABLI UNIT RI AND fS DOCUHENTS
COMHENTS ON fINAL fIRST OPERABLE UNIT RI AND FS DOCUMENTS
COMHENTS ON FINAL fIRST OPERABLE UNIT RI AND fS DOCUHENTS
COHHENTS ON fINAL fIRST OPERABLE UNIT RI AND fS DOCUHENTS
COHMENTS ON FINAL fIRST OPERABLI lINIT RI AND fS DOCUMENTS
COMMENTS ON fINAL fIRST OPERABLE lINIT RI AND FS DOCUMENTS
STATE LITTER ON APPLICABj.E RELIVANT AND APPROPRIATE
REQUIREMENTS FOR OFf-PO~-aBEA
COMMENTS ON FINAL fIRST OPERABLE UNIT RI AND fS DOCUMENTS
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