United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EP AIRODIR08-93/076
December 1992
PB94-964414 -
&EPA
Superfund
Record of Decision:
Chemical Sales, CO
u. S. Environmental Protection Agency...
Reqion Iii Ha.zardous Waste
Technical Information Center
841 Chestnut Street., 9th Floor
. . elo i
I
Hazardous Waste Collection
Information Resource Center
US EPA Region 3
Philadelphia, PA 19107
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50272-101
REPORT DOCUMENTATION 11. REPORT NO.
PAGE EPA/ROD/R08-93/076
2.
3. Reclplenra Acc8aalon No.
4.
T"la and Subt"1a
SUPERFUND RECORD OF DECISION
Chemical Sales, CO
Fourth Remedial Action - Final
Author(a)
5.
Report Date
12/29/92
6.
7.
8.
Parformlng Organization Rapt. No.
9.
Partormlng Organization Nama and Addr-
10
ProJact TaakIWork Un" No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Nama and Add...a
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Raport & Parlod Covared
Agency
800/800
14.
15. Supplementary Notaa
PB94-964414
16. Abatract (Llm": 200 worda)
The Chemical Sales site is an active chemical sales and storage facility in Commerce
City, Adams and Denver Counties, Colorado. Land use in the area is predominantly
industrial, with six residences located on the northern portion of the site. The site
borders Sand Creek to the north and the Rocky Mountain Arsenal Superfund site to the
east, and lies within the 100-year floodplain of Sand Creek. An estimated 30,000
residents living near the site use the South Adams County Water and Sanitation District
Wells (SACWSD) 18, 21, and 47, which draw from the shallow alluvial aquifer, as their
principal sources of drinking water. Since 1976, Chemical Sales has used the site to
store and sell organic chemicals and acids. Site features include a warehouse and tank
farm, including an associated system of above-ground and underground storage tanks and
pipelines. In 1981, a random EPA sampling identified several organic chemicals in
on site wells located along the eastern portion of the site, and additional sampling in
1982 and 1985 confirmed these results. Between 1985 and 1990, three onsite chemical
releases of hazardous substances into the soil and ground water from the facility were
reported. In 1985, approximately 200 gallons of methylene chloride were released
during an onsite chemical transfer. In 1986, VOC-contaminated rainwater was discharged
directly into a nearby drainage ditch. In 1987, EPA selected a permanent water
(See Attached Page)
17. Document Analyala a. Daacrlptora
Record of Decision - Chemical Sales, CO
Fourth Remedial Action - Final
Contaminated Medium: gw
Key Contaminants: VOCs (benzene, PCE, TCE)
b.
IdentifieralOpen-Endad Tarma
c.
COSATI FlelcilGroup
18. Availability Statamant
19. Security Class (thIs Raport)
None
20. Security Class (thIs Paga)
None
21. No. of Pagas
56
22. Prlca
(Saa ANSI-Z39.18)
SHlnstruet/ons on R.v.f811
OPTIONAL FORM 272 (4-77)
(Formerly NTI5-35)
Dapartmant of Commerce
-------
EPA/ROD/R08-93/076
Chemical Sales, CO
Fourth Remedial Action - Final
Abstract (Continued)
treatment plant to address the previously identified onsite ground water contamination
along the eastern portion of the site. In 1990, approximately 3,700 gallons of methanol
were spilled on the ground surface near the tank farm. . As a result of these spills,
subsequent EPA investigations have confirmed the contamination of onsite soil and ground
water. This site was divided into four OUs for remediation. Three 1991 RODs addressed
contaminated soil on and adjacent to the site and contaminated ground water south of Sand
Creek, contaminated ground water north of Sand Creek, and exposure of residents to
contaminated ground water through the use of affected private alluvial wells, as OUs 1, 2,
and 3, respectively. This ROD addresses exposure or potential exposure to contaminated
ground water used as a drinking water source from supply weils 18, 21, and 47. The
primary contaminants of concern affecting the ground water are VOCs, including benzene,
PCE, and TCE.
v
The selected remedial action for this site includes connecting wells 18, 21, and 47 to the
Klein Water Treatment Facility, a local POTW; treating contaminated ground water offsite
using granular activated carbon (GAC) to remove VOCs, followed by offsite regeneration of
the spent carbon; installing an air stripping unit, if the GAC treatment system is not
effective at reducing vinyl chloride contamination to below MCLs; storing treated ground
water in an offsite reservoir for future use; and monitoring ground water. The estimated
present worth cost for this remedial action is $3,314,900, which includes an estimated
annual present worth O&M cost of $1,013,100.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific ground water cleanup goals are based on Federal and State ARARs and SDWA
MCLs, and include benzene 5 ug/l; DCA 5 ug/l; 1,1-DCE 7 ug/l; 1,2-DCE 70 ug/l; PCE 5 ug/l;
TCA 200 ug/l; TCE 5 ug/l; and vinyl chloride 2 ug/l.
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Ii! III' 1111111 Iii III' ~ 11111\11 'II
I 111'111111 ,1,;:1
I "I I II..
014295
.'
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. .. .'~ . :.-:.,'..'. .
. '. ...: .,'..;.-: .-"
...
DECLARATION OF TEE RECORD OF DECISION
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"
The Chemica1 Sa1es Company (CSC) SuperfUnd Site, Operable Unit 4
(004), Commerce City, south ].nJ'lmJ't County, Colorado
statement of Basis and Purpose
This decision document presents the selected remedial action
(RA) for Operable Unit 4 (OU4) of the CSC Site, located in
,. :.'.' Commerce. City Colorado, which was chosen in accordance with
" . ...' Compreh~sive Environmental Response, Compensation, and Liability.-
Act '(CERCLA), as amended by Superfund .Amendment and
Reauthorization Act (SARA), and to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan
(NCP). OU4 .includes South Ad~s County Water and Sanitation
District (SACWSD) .Wells 18, 21 and 47, which are currently used
as sources of drinking water for south Adams County residents.
This decision is based on the Administrative Record for the Site.
The State of Colorado concurs with the selected remedy.
Assessment of the Site
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an
~inent and substantial endangerment to public health, welfare,
or the environment.
Description of the Selected Remedy
The objective of the OU4 remedy is to minimize or eliminate
exposure or potential human exposure to contaminants present in
the contaminated ground water. SACWSD wells ~8,2~, and 47. are
used as a drinking water source. The RA for OU4 will connect
these wells to the Klein Water Treatment Facility (KWTF). Water
from those wells will be pumped to the existing treatment
facility where it will be treated to drinking water standards
before being distributed to users. The RA for Wells ~8, 2~, and
47 will continue as long as the KWTF is operating for puposes and
reasons specified ~n the ~EPA RMA Off-Post" ROD, June ~987.
OUl addresses soil and ground water remediation at CSC
property and adjacent areas. OU2 addresses remediation of ground
water north of Sand Creek. OU3 involved the connection of
several residents to the municipal water supply. The RMA Off-
Post OUl ROD addressed contamination from various sources.
No principal threat exists in CSC OU4. Nevertheless
treatment is used as a major component of the remedy.
Statutory Deter.minations
D-l
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The selected remedy is protective of human health and. the
environment, ) complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the RA, and
is cost-effective. This remedy utilizes permanent solutions and
alternative treatment technology to the maximum extent
practicable, and satisfies the statutory preference for remedies
that employ treatment that.reduces toxicity, mobility, or volume
,/".~~~(:a:.principal element.' .
".. ',~,':;,"'''.''':....:.:.~''.~'.. ".:-.":- . .
Because this remedy will result in hazardous substances
remaining on-site above health-based levels, a review will be
co~ducted within five years after commencement. of RA to ensure
that the remedy continues to provide adequate protection of human
health and the environment. . . .
~ -2.7 /1'2.-
Date
Agency
!)-2
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TABLE OF Cmt.J:lSbI'rS
I. SITE~AME:, LOCATION, AND DESCRIPTION. . '.
II.
. .-...
."'- ... . '..' . - - .
'-'" ,':,-'."...:.-",' .
.'-.' ':'" :..
III.
IV. '
.V.
VI.
VII.
. . . . .
. . .
SITE HISTORY AND 'ENFORCEMENT ACTIVITIES
.Notice Not to Issue Special Notice. .
. . . . .
. . .
.........
'RIGHLIG1I'l'S OF COMMUNITY INVOLVEMENT
.........
SCOPE AND ROLE OF OPERABLE UNITS WITHIN SITE STRATEGY
SUMMARY OF SITE CHARACTERISTICS. . . . . . . . . . . . .
Nature and Extent of Contamination. . . . . . . . . . .
SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . . .
A. Ruman Health Risks. . . . . . . . . . . . . . . .
Toxicity Assessment. . . . . . . . . . . . . . . .
Exposure Assessment. . . . . . . . . . . . . . . .
Resul ts . . . . . . . . . . . . . . . . . . . . . .
B.
Environmental Risks.
. . . . . .
. . . . . .
. . .
DESCRIPTION OF ALTERNATIVES.
. . . . . .
. . .
. . . . .
Remedial Action Objectives and Goals
. . . . . . .
. . .
Alternative ~
Alternative 2
Alternative 3
- No Action. . . . . . . . . . . . .
- Screened-Out in OU4 FS -.. . . . . .
- Connection to the Klein Water
Treatment Facility. . . . . . . .
- Granular Activated Carbon
Trea tmen t . . . . . . . . . . . . .
- Air Stripping Treatment. '. . . . .
Alternative 4
Alternative 5
VIII.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
. . .
Overall Protection of Human Health and' the Environment.
Compliance wi th ARARs. . . . . . . . . . . . . . . . . .
Long-Term Effectiveness. . . . . . . . . . . . . . . .
Reduction of Toxicity, Mobility, or Volume. . .' . . . .
Short-Term Effectiveness. . . . . . . . . . . . . " . .
:rmplementabili ty . . . . . . . . . . . . ,. . . . . .' . .
Co st. . . . . . . . .
. . . . . . . . . .
. . .
. . . .
State Acceptance. .
Community Acceptance
. . . . .
. . . .
. . .
. . . . . .
. . . . . .
. . .
. . . .
. . . . .
IX.
SELECTED REMEDY
. . . . .
. . . . . . . . . .
. . . . .
X.
STATUTORY DETERMINATIONS
. . .
.......
. . . . . .
i
1
4
7
7
8
9
9
11
~1
~3
~4
15
~6
~6
~6
17
~8
18
20
21
22
22
22
23
23
24
24
24
24
25
25
26
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.. :'~""':"".".'~'- _. .
. '-.-- - . .,' .."..' '.-.
-. -- _: -....'
Protection of Human Health and the Environment. . . . .
Attainment of Applicable or Relevant and Appropriate.
Requiremen ts . . . . . . . . . . . . . . . . . . .
Cost Effectiveness. . . . . . . . . . . . . . . . . . .
utilization of Permanent Solutions and Alternative
Treatment Technologies .or Resource Recovery .
Technologies to the Max~um Extent Practicable
Preference for Treatment as a Principal Element. . . .
Documentation of Significant Changes. . . . . . . . . .
REFERENCES
. . . .
. . .
. . . . .
. . .
. . . . .
. . . . .
'APPENDIX A
. . . . . .
. . . .
. . .
. . . . . .
.. . . . . .
CHEMICAL SALES COMPANY SUPERFUND SITE OU4
RESPONSIVENESS SUMMARY
. . . .
. . . .
COMMENTS AND RESPONSES.
. . . .
. . .
. ,. .
. . .
. . .
APPENDIX B
. . . . . . .
. . . .
. . .
. . . . . . . .
. . .
26
26
26
27
28
28
29
30
3~
32
37
ARARs AND PERFORMANCE STANDARDS FOR CHEMICALS OF CONCERN. 38
APPENDIX C . .
. . . . . . . . . . .
. . . . .
. . . . 50
. . . .
STATE CONCURRENCE.
. . . . . .
. . . 5~
. . . . .
. . . . .
ii
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.r
1:. SITE NAME, LOCATION, AND DESCRIPTION
The CSC superfund Site is located in Commerce City and north
Denver, Colorado. It is approximately five miles northeast of
downtown Denver, Colorado. Contamination at this Site consists
of soils and o ground-water contamination. The contaminated. ground
.. .'water is located in an -u'nconfined alluvial aquifer I which extends
.:.~.:~::~:to::a:~'rila.ximum depth of 100 feet below the ground surface.. Ground-
water flow on the Site generally trends north to northwest.
However, paleochannels also influence regional flow at times
resulting in flow patterns that 'are not in the same direction as
the above mentioned general flow patterns. The Site is divided
into four .OUs: ~
OU1: Includes the CSCproperty and addresses soil and
ground-water contamination south of Sand Creek. .The approximate
boundaries are Forest Street to the west; Monaco Parkway to the
east; I-70 to the south; and Sand Creek to the. north (see Figure
~-~, page 2). The land use in ou~ is mainly industrial with six
residences located in the northern portion.
. .
The CSC property is the location of an operating chemical
sales business. Soil contamination on and adjacent to the
property is considered to be a source of ground-water
contamination on this Superfund Site. The contaminated ground
water flows northward into the other CSC.OUs.
OU2: Addresses ground-water contamination generally
downgradient of OU~. . The approximate boundaries are Holly Street
to the west; Quebec Street to the east; Sand CreeK to the south;
and 86th Avenue to the north (see Figure l-~,.page 2). The Rocky
Mountain Arsenal .(RMA) borders OU2 to the east. OU2 is
approximately four square miles in area. The land use consists
of single and multi-family residences, small businesses, and
munici~al facilities. Boundaries of OU~ and OU2 are defined by
the approximate extent of ground-water contamination, and may.
expand as ground-water contaminants migrate. No soil
contamination has been found in this OU.
OU3: OU3 provides for those residents located in OU2 that
are using alluvial well water for domestic uses to be connected
to the municipal water system. This reduces their exposure to
the contaminated ground water. of OU2. OU3 has the same
boundaries as OU2. .
OU4: OU4 addresses SACWSD Wells ~8, 2~, ar..d 47~ and' is the
subject of this ROD. Wells 18, 2~ and 47 are wells that draw.
water from the contaminated alluvial aquifer in and north of OU2.
These wells are for purposes of providing water for domestic uses
for residents connected to the SACWSD.
J.
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Figure 1-1
Site Location Map
. ..
',' _.. ... ~ .~"::". . :-.: : '. :f ';' ;"~': :~:.;'~.~-:...:;:",,:: ';.'. .
. .' .".'_."" ," ..,. "~~""'Ul~
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. ..
. . ...... '.'
. . '.
. Figure 1-2-
Groundwater Plumes/'Well Location Map
PLATTE
RIVER
E88th
.. ---." --,--
~
:< >- ROCKY
c a::
c=: MOUNTAIN
o ARSENAL
z
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0
CO
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SCALE
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. 1-70
LEGENC
g=PW14
F1GURE 1-2
GROUND.WATER
PLUM:ES I WELL
LOCATIONS
~
~ 1""-1 1"..:.:)4
UG-II ~~
o ~we.L.
3
-------
. .
Well ~8 is located at 84th Avenue w~d Quebec Street and is
within OU2 boundaries and is generally west of the RMA. Well 47
is located at 88th Avenue and Quebec 'Street, and is two blocks
north of the OU2 northern boundary and is also gen~rally west of
the RMA. Well 21 is located at 90th Avenue and Ulster Street
. '
.and ~s four blocks north of the northern boundary of OU2 and is
also generally west of the~ (see .Figure ~-2, page 3). These
". -",>~:'.w.e~,ls.:,.
-------
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~OAADO BLVD, ~".
\lOLLY ST,
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0-4
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nOCKY MOUtfT AIN AnSENAL '
-------
facil~ty was confirmed by another soil gas survey in August ~987.
Gro~d-water monitoring wells installed on CSC property have
conf~rmed CSC as a source of ground-water contamination.'
. Based on these studies and additional work by EPAto define
. the source areas, theCSC Site wa~ proposed for listing on the
._...,}~at~onal pr:!-orities List (NPL) in June ~988. Investigations for
-.:<-:-':alL:.EP.A:RMA .Off-Post work was then transferred from the EPA Off-
Post RMA Study Area to the CSC Site'. The NPL listing was made
final in August ~990. The.EPA RMA Off-Post OU~ and CSC
geographic areas overlap (see figures ~-2 and. ~-3) .
Two distinct ground-water plumes have been identified within
the CSC Site. The first plume, known as the "CSC plumell or the
"TCE plume", .originates on CSC property south of Sand Creek and
is characterized by high TCE concentrations. The second plume,
known as the "perchloroethylene (PCE) plume", originates near'
56th Avenue and Quebec Street and is characterized by high PCE
concentrations. Both plumes are 'located in the shallow alluvial
aquifer, with the direction of migration generally following the
direction of the ground-water flow, which, as mentioned earlier,
is generally north to northwest. The direction of flow has been
noted to vary from the general flow directions when influenced by
the presence of paleo-channels. Historically, there have been
indications of contamination migration from the ~-~ property.
Although the plumes are noted to be characterized by TCE and
PCE, they contain many other contaminants. A list of the current
COCs at the Site is presented on page 9 of this document.
During the development of the RI/FS for CSC OU2, samples
taken from SACWSD Well ~8 showed TCE levels above the MCLs. Well'
monitoring has continued since that time, and elevated TCE
concentrations have been recorded on a consistent basis.
Currently Well ~8 is utilized during high demand periods only
(typically May - September). Since the initial detection in Well
~8 in ~98~, the presence of TCE in well water samples has
persisted, while concentrations have fluctuated. In the past,
. water from Well ~8 has been blended with treated water from
SACWSD Wells 2 and 3 so that water distributed to SACWSD
customers does not exceed the MCL for TCE. The effectiveness of
the blending' program is limited by the amount of treated water
available to blend with contaminated flows. As future demands
and contaminant levels rise, an insufficient quantity of treated
water will be available to adequately blend the contaminated
flows and continue to meet public water use demands.' . Tlius, the
. blending program is a temporary solution to current well water
contamination problems, and it is not considered to be a viable
treatment alternative to meet RA objec~ives.
Wells 47 and 2~ are sicuated north anc hydrogeologically
dowr.gradient from Well ~8. Well 47 was installed in ~990,with
6
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sampling beginning at that time and continuing to present. No
contamination had been detected in Well 47 until July 1991. From
,July 1991 to ~Ay'1992, eight out of ten samples have shown
contamination. As of May 1992, TCE concentrations ' were below
MCLs.
"
Well 21 had not exhibited ,any volatile organic compounds',
,: ':'" FX(VQCL'cqntamination as of May ,1992. Considering, Wells - 18, 47,
and 2,1' 'lie downgradient of the CSC' plume and the PCE plume, EPA
'and the State believe that it is reasonable to expect future
contamination of Well 21 and increased contaminant concentrations
in Wells 18 and 47.
Notice Not to Issue Special Notice
Because the potentially Responsible Parties (PRPs) have
indicated that they are not willing to do any work north of Sand
Creek on this site, EPA issued notices not to invoke the special
notice procedures to all of the PRPs involved with this Site.
These notices were issued June 30, 1992. The purpose of these
notices is to notify the PRPs of their liability and let them
know that EPA will not conduct negotiations with them for '
, performance of the work in this QU.
III.
HIGHLIGHTS OF CQMMcrNITY INVOLVEMENT
Community interest in ground-water contamination in south
Adams County was very intense in 1985 and early 1986. Initially
the RMA was thought to be the sole source of the contamination.
Local citizens formed a group, Citizens Against Contamination
(~~C), which held a'number of well attended meetings (over 600
attended the March 6, 1986, meeting). EFA and the Army responded
to numerous public and media inquiries; issued press releases for
new developments; and attended the public meetings. Community
relations activities were coordinated among the EFA,the Army,
and the SACWSD. The State conducted a separate program.
Public interest subsided in mid-1986 after a temporary water
treatment system funded by the A-~y and authorized by a removal
action by the EPA came into o~eration at SACWSD and treated water
was thus made available to the affected residents. In the fall
of 1986, EPA named the CSC as another source of the ground-water
contamination. EPA has since issued a number of fact ,sheets
discussing the progress of the investigation and activities at
the site. The CSC Site was also included in joint community
relations activities with several other south Adams County
Superfund Sites.
proposed plans 'for OU1, OU2, and OU3 were j.ssued
concurrently on February 25, 1991. The public comment period was
open from February 28, 1991, to April 1, 1991. A public meeting
was held March 14, 1991, at the Commerce City Rec=eation Center
7
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~nd was 'attended by 50-75 people~ Details about community
~nvolvement throughout the RI/FSs and public comment. period are
included in the responsiveness summaries in the RODs for OU~,
OU2, and OU3.
During the latter portion of the RI/FS for OU2, it was
. ..discovered . that SACWSD Well ~8 began to show levels of TCE above
.-~;':;~'1J:'1~~_~;~.'h~: In. response to this finding, OU4 was created to address
. ... .~ the-' contamination or potential contamination in SACWSD Wells ~8,
2~, and 47. The proposed plan for OU4 was issued on
July ~O, ~992. The public comment period was open from
July ~O, ~992, to August 8 i ~992. A public meeting was held at .
the Commerce City Recreational Center on July 2~, ~992. Fourteen.
individuals were present at the meeting, including
representatives from EPA, Colorado Department of Health (CDH),
CAC, State Senator Dennis Gallagher's office and SACWSD.
Responses to comments received during the public comment
. period on the proposed plan are presented in the Responsiveness
summary of this document (see Appendix A) .
IV.
SCOPE AND ROLE OF OPERABLE UNITS WITHIN SITE STRATEGY
. .
As stated previously, the CSC Site has been divided into
four OUs: OU~, which addresses contaminated soil on and adjacent
to the CSC property and ground-water contamination south of Sand
Creek; OU2, which addresses ground-water contamination north of
Sand Creek; OU3, which addresses exposure of residents to
contaminated ground water from use of private alluvial wells in
OU2; and OU4, the subject of this ROD, which addresses exposure
or potential exposure to contaminated ground water used as a
drinking water source by SACWSD from supply wells ~8, 2~, and 47.
The EPA'Off-Post ~~ OU1 ROD is also relevant. at the.CSC
.Site. It first addressed exposure or potential exposure to
contaminated ground water used as a drinking water source by
SACWSD and by private alluvial well users. The EPA Off-Post ~A
OU~ ROD was issued June 4, ~987.
The RA objective of OU4 is to minimize or eliminate exposure
or potential exposure to contaminants present in the contaminated
ground'water, used as a drinking water source by SACWSD from
Wells ~8, 2~, and 47, in order to protect human health in the
present and future. Remedial alternatives evaluated under OU4
reduce exposure, for customers of SACWSD, to contaminated ground
water from supply Wells 18,21, and 47. The RA for Wells 18, 21
and 47 will continue as long as is necessary to insure the MCLs
are met at the drinking water tap. MCLs at the drinking water
tap will. be achieved via treatment by the KWTF which was
ccnstructed as a result of the EPA RMA Off-Post OU~ ROD, dated
June 1987. .
8
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The primary purpose of OU4 is to ensure the provisis'on of an
ade~~at~ drinking water supply to the residents of south Adams
County. OUs ~ and 2 are for purposes of restoring the aquifer
to MCLs for the COCs and this restoration'will be e~~anced by the
actions taken in the EPA RMAOff-Post OU~ ROD. .
,
The .objective of the
/...;::(.J~liminate . the exposure to
""..". conta.Ininated ground water
SACWSD in order to assure
EPA Off-Post RMA OU~ was to minimize or
the contaminants present in the.
used as 'a drinking water' source by
protection of the public health. .
The ROD for the EPA Off-Post RMA OU~ called for the
construction of the KWTF and treatment of drinking'water to
acceptable standards (see table B-4, Appendix B) using a
Granulated Activated Carbon (GAC) system. At that time, ,six
SACWSD supply wells were connected to the KWTF. At the time of
KWTF construction (~987 to ~989), Wells ~8 and 2~ were not'
connected to' the KWTF, because they' failed to exhibit significant
cont~ination. Well 47 was not: installed until ~990. However,
sampling in May'~990, showed contaminants had migrated to the
ground water drawn by Well ~8, and contamination was detected in
Well 47 in July. of ~99~. To date, Well 2~ has not exhibited
detectable contamination, however its is positiondowngradient of
the CSC 'and PCE plumes and the ~M_~ Off-Post area. This indicates
contamination in the future is probable.
No principal threat exists in CSC OU4. A principal threat
is defined as material that includes or contains hazardous
substances, pollutants or contaminants that act as a reservoir
for migration of contamination to ground water, to surface water,
to air, or acts as a source for direct exposure. contaminated
ground water generally is not considered to be a source material.
An exception to this is the presence of Non-Aqueous Phase Liquids
(NAPLS) in ground water (see superfund publication 9380.3-06FS,
Nove-rnber ~99~) .
v.
S"CMMARY OF SITE CHARAC'TER.ISTICS
Nature and Extent of cont~ination
The RI for CSC OU2 is the basis for information on the
nature and extent of contamination in OU4. The results of the
CSC OU2 RI showed extensive ground-water contamination by VOCs in
the study area. Contaminants were not detected in ,other media.
The chemicals of concern (COCs) in the ground water are:
~,~-dichloroethane (DCA)
~,~-dichloroethylene (DCE)
Total ~,2-dichloroethylene {total
. (the sum of the trans and cis
~,~,~-trichloroethane (TCA)
Trichloroethylene (TCE)
~12-DCE)
isomers)
9
-------
Tetrachloroethylene
Benzene (BZ)
Vinyl Chloride (VC)
(PCE)
This group of contaminants is generally mobile in ground water.
Please refer to Section VI of this document for the toxicity
c!laracteristics of the above. COCs ~ ..
. . .' .
':-~'.:.:.:~:.~.;:i:~S?K;r:c-E was first. discovered in SACWSD Well ~8 in .
. August 26, ~982, and first exceeded the MCL of 5 parts per
billion (ppb) in. May ~990. Since May ~990, measurable
concentrations of TCE have persisted. Thus far the highest
concentration of TCE has been ~2 ppb. This was recorded in May
~990.. Concentrations of PCE, ~,~,~-TCA, ~,~-DCA, Cis-~,2-DCE,
and ~,~-DCE have also been detected, but the concentrations are
below their respective MCLs. BZ and VC have not been detected in
Well ~8. .
Well 47 first showed TCEcontamination in July 199~. All
subsequent samples obtained have exhibIted detectable levels of
TCE .with two exceptions: Those obtained in December 199~ and
January 1992. All Well 47 concentrations for TCE have measured
below the MCL. PCE concentrations of ~.O ppb were recorded in .
three sampling events during October and November, ~99~. Samples
obtained since that period have not exhibited PCE concentrations
above detection level. The other COCs are either not present or
are in concentrations below detection level.
Well 2~ has not shown contamination to date, bQt its
downgradient position from Wells ~8 and 47 indicates that future
contamination is probable. The contamination trends of Wells 2~
and 47 can be expected to follow the trend of Well .~8, i.e. after
initial detection, the presence of contamination persists. Based
on ground-water flow direction and recent sampling of upgradient
wells, it is anticipated that contaminant concentrations in Wells
~8, 2~, and 47 'will increase in the future.
Sources of contamination for areas affecting Wells ~8, 2~
and 47 are the TCE plume emanating from OUl, the PCE plume
emanating from OU2 and from the on-post RMA. .
As mentioned previously, the TCE plume originates from the
CSC facility in OUl. The plume follows the flow of ground water
north into OU2. The plume is characterized by high levels of TCE
in mean conce~trations exceeding 50 ppb in upgradient portions of
OU2. PCE, TCA, and ~,2-DCE are also present within the pl~~e
bounds, the areal extent of which ranges from the CSC property in
OU1 to SACWSD. Well 47, (see Figure 1-2, page 3 of this document).
Concentrations decrease steadily downgradient from the CSC
property. This is believed to be due to dilution, dispersion,
adsorption, and biodegrada~ion of the cOilt~~nation. .
:1.0
-------
The PCE plume appears to emanate from the vicinity of the
northwest corner of the intersection of East 56th Avenue and
Quebec Street. It is characterized by PCE, with concentrations
as high as ~~O ppb. This plume is also moving northward~ The
.exact source of the PCE plume has not been determined. It has
been assumed that the'PCE plume source is .degrading for two
'.reasons: ~) field'investigations to date have not located a
-:'\$"Oil:eFe-and .2) recent sampling indicates the _plume is dispersing.
In addition to the TCE/CSC and PCE plumes in CSC OU2, a
plume consisting of dibromochloropropane (DBCP) and other VOCs
lies .east of CSC OU2, on RMA property. This contamination was
detected in Irondale community wells in ~980 and was traced back
" to the western tier of RMA. A ground-water interception system, '
known 'as the Irondale System, was installed at the.RMA boundary
in December ~98~, to prevent this contamination from further
migrating off RMA. ,
, Subsequent to the ~981 inst~llation of the Irondale System,
it was observed that the behavior of the contamination on the
western tier of the Arsenal was influenced by SACWSD ground-water
extraction practices and schedules. During normal operations,
SACWSD pumps considerably more water during the summer than at
, other times of the year. There was concern that during periods
of higher rates of SACWSD ground-water extraction, the direction
of local RMA ground-water flow might be altered, causing
contamination on the western tier of the Arsenal to deflect to
the south and partially bypass the Irondale System. This was
evidenced by detection of low levels of DBCP in sQme SACWSD wells
in ~989. Improvements to the Irondale System were made in ~990,
and there has been no detection of DBCP in SACTilSD wells since.
Vinyl chloride was detected during the CSC OU2 RI and
subsequent field sampling programs. This compound is a breakdown
product of other chlorinated hydrocarbons detected at the Site
(see Figure 1-4; page 12 of this document). It ,was detected only
sporadically with respect to location and concentration, and it
did not appear to define a continuous plume. The ROD for the EFA
Off-Post RMA OUl Site contains provisions to upgrade the KWTF
with an air stripper to remove vinyl chloride from the SACWSD
water supply if it ,becomes a threat to public health via the
water supply from KWTF.
The CSC OU2 RI and subsequent sampling in OU2 and OU4
constitute the RI for this CSC OU4 ROD.
VI.
SUMMARy OF SITE RISKS
A.
Human Health Risks
Actual or threatened releases of hazardo~s substances from
CSC OU4, if not addressed by implementing the response action
~1
, !
-------
ANA~~OeQC B~ODEG!PlADA"UON PAT~WAYS
:', :...
. "
" .
, ,~ "."' ".', .c",;;:,,:"h;-;:!:: I PIE I
; v
. T
TCE
K "
\1M
ETHYLENE
K
"f
ICH4\
S-L - BARRJO-LAGE. 1986
K .. KUHN. 1986
V II: VOGEL. 1985
W - WOOD, 1985
VM .. VOGELANDMcCAR1Y.1987
B - BOUWER. 1983
P - PARSONS ET AL. 1982.1983
CSC SITE OUl RISK ASSESSMENT
Figure 1-4
ANAEROBIC BIODEGRADATION
PATHWAYS .
Cl-JI' :.oov 8!S' 4< w..IU5! J«:I,.
~ 110.
04/01/90
»W!OEC.C'I'IC
CDM
c::a.I n8lC>-o:)o4
-" -
12
-------
seiected in this ROD, may present an imminent and substantial
endangerment to public health.
,
The major potential health risk to area residents is
associated with the use of ground water contaminated by VOCs.
CUrrently, all of .the.ground water is treated or blended prior to
distribution to the community. .SACWSD Wells 18 and 47 are'
,"',:. ~urrently impacted by contariLination. It is expected. tp.at Well 21
. - will be" iinpacted in the future ~ Water from Wells 18 and 47 is
blended with treated water from the KWTF to levels below MCLs,
before distribution to residents.
As mentioned previously, eight COCs have been identified.
based on their toxicity, widespread occurrence, or' concentration.
These compounds are PCE, TCE, TCA, DCA, DCE, 1,2-DCE, VC, and BZ. '
These contaminants are judged to be the source of the potential
health risks at the Site for OU4. .
Toxicitv Assessment
The COCs are a diverse group of volatile halogenated
hydrocarbons and solvents. Most of the COCs are central nervous
system depressants. They are also known to be liver/kidney
toxins at high doses. BZ is toxic to the blood forming system.
Non-Carcinogenic Effects - TCE is a central nervous system
depressant in humans. Inhalation and oral exposure studies in
animals indicate that bone marrow, central nervous system, liver,
and kidneys are the target organs. The principal toxic effects
of PCE in humans and animals are central nervous system
depression and liver and kidney damage. TCA is a central nervous
'system depressant at high concentrations and adverse effects on
the cardiovascular system have also been reported. Exposure to
high concentrations of DCA has been reported to cause cardiac
arrhythmia and liver damage in humans. DCE can induce
neurotoxicity after short-term inhalation exposure, and also is
possibly associated with liver and kidney toxicity after.
reoeated, low-level exoosure in humans,. Benzene'has demonstrated
toxic effects on the central nervoUS system, blood-forming
system, and immune system in both animals and humans. Long-term
inhalation of vinyl chloride by workers is associated with liver
damage, central nervous system disturbances, pulmonary
insufficiency, cardiovascular toxicity, and osteolysis.
Carcinogenic Effects - TCE is classified as a Group B2
carcinogen (a probable human carcinogen). PCE and DCA are also
classified as Group B carcinogens'. DCE is classified as a Group
C carcinogen (a possible .human carcinogen). Benzene and vinyl
chloride have been classified as human carcinogens (Group A) .
Six of the COCs (PCE, TCE, DCE, D~;, VC, and BZ) are ~~own
to cause carcinogenic effects in animal studies. Of the six,
J.3
-------
vinyl chloride and benzene are both classified as Class A -
Carcinogens based on weight-of-evidence for carcinogenicity (see
. EPA Risk Assessment Guidance, EPA/540/1.-89/'002, December ~989,
page 7-11). When.a carcinogen is classified as a Class A,. that
means that there is sufficient evidence from epidemiological
studies to support a caus~~ relationship between the compound and
human cancer.
. '. .. ~ . .
. ,'" _.. . '. .-.
. . .. .
. ""':-<";': '.:~: In the risk' characterization,' the aggregate carcinogenic
risk due to indicator contaminants at the Site is compared to an
, acceptable target risk. Carcinogenic effects are evaluated based
on a calculated increase in the risk of contracting. cancer that
is a direct result of exposure to COCs at a Site. The EPAhas,
defined an increased risk, exceeding the ~04 to 10~ range, due to
exposures at a,Site as being unacceptable regarding the -
protection, of public health and the ,environment (i.e. 1 person in
10~000 to- 1 person in 1,000,000 will contract cancer). RA .
objectives are established based on applicable or relevant and
appropriate requirements (ARARs)' (i. e., MCLs' and MCLGs) and
acceptable risk levels- (i.e., 10~), while ARARs and the ~O~
cancer risk point of departure are used as the basis for
developing preliminary remediation goals. . The chance of one
person developing cancer per one million (or ~O~)is used as the
target value or point of departure above which carcinogenic risks
may be considered unacceptable. The ~O~ point of departure is
used fordeterrnining remediation goals when ARARs are not,
available (i.e., no MCLs or proposed MCLs exist for the indicator
contaminant) or are not sufficiently protective of human health
and the environment because of the existence of multiple
contaminants at a Site or multiple pathways of exposure.
Exposure Assessment
The final CSC OU2 RI report contains a risk assessment for
the CSC Site north of-Sand Creek. This risk assessment will
serve as the risk assessment for this ROD. ,Two exposure
scenarios were developed to describe a range of potential health
risks. Case 1 scenario addresses' reasonable maximum exposures
within the entire QU. The Case 2 scenario in this risk- ,
assessment was 'developed to provide information regarding the
potential health risks. associated with SACWSD Well 18. At the.
time the risk assessment was compiled, average TCE concentrations
ranged from 4 to 6 ppb, with the maximum concentration at 12 ppb.
Water from Well 18 is currently blended with treated water from
the KWTF, to, ensure that any potential contaminant concentrations
in the untreated water are diluted to safe levels. The-case 2 .
scenario provides an estimate of potential health risks if the
water from Well ~8 were to be used directly. The same risk
assessment is applied to Wells 21 and 47.
~4
" ,
-------
The two routes or expos~re pathways evaluated quantitatively
were:
.
~.
Inaestion of the water during normal residential use,
and
2.
Inhalation of volatiles during showering.
. :'~. ,:-~-~~:,::~'~'~~~~~::' ~ : ~',
'. "... .
Results
Based upon the toxicity profiles and the exposure scenarios
developed for the COCs, carcinogenic effects were evaluated for
the Site. For the Case 2 scenario, the total excess cancer risk
was determined to be 2. OX~0.5, indicating that with blending of
treated water from the KWTF, operation of Well~B did not pose an
unacceptable risk to receptors of that water. Risks for each of
Wells 2~ and 47 are considered to be the same as those calculated
, for Well ~B and thus the Case 2 analysis is applied to Wells 2~
and 47.' Although contamination has not reached Well 2~ yet, it
is expected that it will in the future and the risk calculated
for Well ~B will be present~
While the above risk does not exceed the ~o~'point of
departure, the criteria of meeting MCLs does necessitate remedial
action. '
Currently, the blending operations are sufficient for
providing drinking water below MCLs. However, based on higher
upgradient ground-water contaminant concentrationg, a general
increasing trend in contaminant concentrations at the wells that
are already contaminated and, the knowledge of the general
ground-water flow directions, it is anticipated that blending
will not 'be sufficient to supply ground water from Well ~Bat
contaminant levels below MCLs. This same scenario applies to
Wells 2~ and 47. It is anticipated that all three wells may
reach contaminant levels such that blending will not be
sufficient' to provide water at contaminant levels below MCLs. .
This will result in a shortage of water supply for the residents
in south Adams County during peak demand periods.
The chronic Hazard Index (HI) estimate for Case 2, which was
0.008, indicated an extremely low potential for non-carcinogenic
adverse health effectS. Risk Assessment Guidance for superfund"
Vol I: Human Health Evaluation (EPA/540/~-89/002) defines HI to
be the ratio of the exposure level over a specified time period
to a reference dose, below which even sensitive populations are
unlikely to exhibit adverse health effects. A HI of ~~O wo~ld be
the threshold where sensitive populations would possibly begin to
show adverse health effects. ' '
~5
-------
" B.
Environmental Risks
" "
Environmental risks for OU4 were not considered because
there is no identified exposure pathway by which significant
exposure to environmental receptors could occur. There is no
environmental risk forOU4, however, there is potential
environmental risk related to the protection of wildlife on the
~~::~-"~~:~,c::~j~.c::ent.:RMA during construction activities.
v:rI. DESCRIPTION OF ALTElUlATrvES
. .
The CSC OU4FS was conducted to develop and evaluate.
remediaL alternatives that would effectively minimize threats to
and provide adequate protection of public health from
contaminated ground water drawn by SACWSD Wells ~8 and 47 and
will be potentially drawn by SACWSD Well 2~ for use as a portion
of the SACWSD municipal water supply. The OU4 FS was conducted
in three phases: Phase I, development of alternatives; Phase II,
screening of alternatives; and Phase III, detailed analysis of
alternatives. These alternatives were initially evaluated for
effectiveness, implementability, and cost. The favorable
alternatives were then evaluated in detail in Phase III with
respect to the criteria specified in the NCP (seepage 22 of this
document for a listing of the criteria) .
Remedial Action Ob;ectives and Goals
RA objectives for establishing ground-water remediation and
exposure levels were developed from ARARs and from risk-based
considerations (please see table B-4, Appendix B). The
standards, requirements, limitations, ".and criteria that were
considered to be ARARs for remediation at CSC OU4 include
chemical, location and action-specific requirements (see Appendix
B of this document). .
The chemical-specific ARARs pertaining to the CSC OU4 Site
include the Federal Safe Drinking Water Act (SDWA), the 'Clean
Water Act (CqA) , the Clean Air Act (CAA), and the Resource
Conservation and Recovery Act (RCRA). State standards include
the Colorado Primary Drinking Water Regulations and the Colorado
Water Quality control Act. The primary chemical-specific.
criteria for the CSC Site are the MCLs established under the
Federal SDWA and Colorado Primary Drinking Water Regulations.
MCLs are the maximum permissible levels of contaminants in water
delivered to any user of a public water system. Only those State
standards which are more stringent than the Federal standards are
considered ARARs. .
The action-s~ecific ARARs pertinent to remediation
activities at CSC-OU4 include wildlife p~otection (for the
adjacent ~-~), noise abatement, and air emission control
~6
-------
regulations. Applicability of these regulations and standards is
dependant upon specific remedial actions undertaken at CSC OU4.
If air stripping is utilized, then the National Ambient Air
Quality Standards (NAAQS) and the Colorado Air Quality Control
Act would become ARARs. The Colorado Noise Abatement Statute and
Colorado wildlife Enforcement and Penalties are potentially
relevant and appropriate o during 0 construction activities.
,-.. ...
o 0
. .., '-
..0' -000 :o"-0R:A objecti~es define the overall purpose of th~ remediatOion
an~ consist of media and site-specific goals of or protecting human
health and the environment. This project objective was
determined based upon the identified COCs for the Site, the
exposure routes and the acceptable contaminants levels which are
developed fromothe ARARs. The p~ objective can be summarized as
follows: .
" .,-
To minimize or eliminate human exposure or human
potential exposure to cont~~inants present in
contaminated ground water used as a drinking water
source by the SACWSD from Wells 18, 21, and 47, in
order to assure protection of public health in the
present and in the future.
The primary purpose of this RA is to ensure the provision of
an adequate drinking water s~pply to the residents of south Adams
County. In addition, the extraction of the conataminated ground
water by Wells 18, 21 and 47 will assist in capturing
o contaminants in the ground water and is consistant with the OUs 1
and 2 RODs. The above objective is consistent with the RA
objective statement in the EPA Off-Post RMA OU1 ROD calling for
the construction of the KWTF, whereby ground-water contamination
in SACWSD wells south of 80th Avenue was addressed.
Alternative 01 - No Action
This alternative provides the baseline ag~inst which the
other alOternatives are evaluated. Under the No Action
alternative, the current status of the Site remains the same.
Activities currently being conducted fer OU4, which would
continue under the No Action scenario, include the blending
program, which combines water from Wells 18, 21, and 47 with
treated water from Wells 2 and 3, and the monitoring program.
The No Actionoalternative does satisfy the p~ objective of
otheostatutory requirement of protectiveness of human health on a
short-term basis only. Human exposure to contaminated water
through either ingestion or inhalation is temporarily reduced.
The blending program is a short-term temporary means of ensuring
that the water presently delivered to theSACWSD distribution
sys~em meet~ the MCLs. Given the short-term time limitation of
the blending program, however, the RA objective will not be met
in the future under this alternative. .
17
\ ,
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The No Action alternative is both technically and
administratively implementable, as it does not lnvolve any
activities beyond those which are currently taking place at OU4.
Costs associated with the No Action.alternative include
. monitoring and sampling expenses. No capital costs are incurred,
as ,the blending program is in place and operational. The cost'
. ;:;;:-,;;~b:Se:~doWn.' for the 30 year life of the alternative includes:
,Capital Costs
Present worth of Annual O~~
Present Worth Annual Monitoring
$0
$0
$~47,600
-------
-------
Total Present Worth
$~47,600'
Alternative 2 - Increased pumpinq of SACWSD Wells 2 and 3
This remedial' action alternative was not carried forward
into the detailed analysis of the OU4 FS, because it was
determined that it would not capture the plume. Therefore, this
alternative would not be effective because blending of the
cont~~inated ground water would not meet ARARs. (see section 3,
page 4 of ~2 of the OU4 FS Report) . .
Alternative 3 - Connection to the Klein Water Treatment Facilit
This alternative is a Granular Activated Carbon (GAC)
treatment option. Alternative 3 involves the connection of Wells
18, 21, and 47 to the KWTF where the existing GAC system would
,treat the contaminated ground water to below MCLs. The treated
water would then be transported 'back to a storage reservoir for
distribution. .
The KWTF, located at 74th Avenue and Quebec Street, consists
of ~6 downflow, fixed-bed GAC pressure contactors, with two
, additional units for carbon storage and reserve capacity.
Chlorine and chloramines can be added to the flow either before
or after carbon adsorption, and provisions have been made for,
via the BPA Off-Post RMA OU~ ROD, the addition of an air
stripping unit if it is determined that VC contamination is
evident and in exceedence or the MCLs. The spent carbon, which
was delisted by COH in January ~992, is categorized under the
"nonhazardous II designation. It is currently transported off site'
and regenerated in compliance with the EPA Off-Post RMA OUI ROD.
~ollowing treatment, the water is pumped to a clearwelland then
pumped to SACWSD's storage reserves. The monitoring program at
the KWTF tracks influent and effluent water quality and plant
performance to aid SACWSD in the effective operation of the'
~ . , . T- .
_ac!._J..-Y.
~8
-------
Wells 18, 21, and 47 currently pump to Reservoir 4, a
2,000,000 gallon reservoir and pumping station located at 85th
Avenue and Quebec Street. The capacity of the storage reservoir
and the 12 million gallon per day (mgd) KWTF are adequate to .
handle the treatment and storage of water from the wells in CSC
O~. .
.,
, . 'Instantaneous decreed and design flows are as follows:
18
21
47
Instantaneous Decreed
Flow (gpm)
3088-
2000
1500
1989 Design Flow
(gpm)'
SACWSD Well
.1500
2000
1500
- Well 18 is an alternate point of diversion
for Wells 2 and 3. There~orei Wells 2, 3
and 18 qaye a combined rnaximumwithdrawal
rate of 3088 gpm.. '(Black & Veatch, 1989).
",
, Based upon SACWSD design flow rates and approximate pipe
slopes and velocities of 3 to 5 feet per second, the connection
of all three wells to the ~NTF would consist of the following
arrangement (these specifications may be modified during system
design if necessary) : .
24" collection line from the junction of Wells 18, 21, and
47 at Reservoir 4 to the KWTF; and
20" transmission line from the KWTF to Reservoir 4.
The connection o~ ,Wells 18, 21, and 47 to the KWTF would
redu~e the contamination levels in the water, thereby minimizing
future public exposure to the contaminated ground water and
meeting the RAobjectives. The GAC system at KWTF has proven to
be effective in removing the VOCs found in the CSC shallow'
al~u~lial aquifer, resulting in potable water meeting the state
and federal drinking water standards. The treatment of water
from the three wells via the KWTF would ensure adequate removal
of all COCs with 'the exception of vinyl chloride. If vinyl
chloride is detected at the KWTF at concentrations in excess of
MCLs an air stripper will be added to the treatment proc~ss.
Alternative 3 is technically and administratively
implementable. The Klein GAC system is fully operational and is
designed to provide adequate capacity for the treatment of
cont~~inated water from Wells 18, 21, and 47. Construction of
approximately 20,000 feet 6f pipe would be necessary in order to
L~,clement Alternative 3. The acauisition of the necessary
easements ahd/or rights-of-way will also be necessarJ. The
19
-------
preliminary general alignment of the connection to the "KWTF
prL~rily runs parallel to existing roadways where SACWSD
easeme~ts have already been acquired. The widening of existing
easements and/or the acquisition of new easements is not
anticipated to be difficult to implement. '
Costs associated with Alternative 3 include collection and
,-" transmission lines, new well pumps, and' design and construction
engineering. The cost breakdown for the 30 year life of the
alternative includes:
capital Costs
Present Worth of Annual, O~~
present Worth of Annual Monitoring
Total present worth
I'
$2,30~,800
$865,500
$~47,600
---------
---------
$3,3~4,900
Alternative 4 - Granular Activated Carbon Treatment
Alternative 4 involves the use of a new GAC treatment system
for the contaminated water from Wells ~8, 2~, and 47, as opposed
to the use of the KWTF GAC system. This treatment option
consists of constructing a permanent GAC system at the Reservoir
4: storage facility. '
The GAC system would require ~4 downflow fixed-bed GAC
pressure contactors with one additional unit for carbon storage
and reserve capacity. As at the KWTF, chlorination would be
provided prior to pumping ~he treated water to Rese~oir 4. A
monitoring program similar to that established at the KWTF would
be implemented. All contactors would be tested and monitoring of
the influent and effluent water quality would be necessary to '
ensure that all flows entering the SACWSD distribution system
meet the State and Federal drinking water standards. provisions
for the addition of an air stripping unit would be made should
the presence of vinyl chloride be detected in the plant influent.
The' RA objectives wquld be met and public contact with
contaminated water would be reduced by installing a GAC system
for the treatment of water from Wells ~8, 2~, and 47. Reduction
of the toxicity, mobility and volume of the COCs would be '
accomplished, with the exception of vinyl chloride. If vinyl
chloride is detected, an air stripping unit would be added to the
treatment process. .
Alternative 4 is technically and administratively.
implementable. Construction of the GAC treatment system would be
required to impl~~ent the alternative. The ,system would not
require pilot testing, since a GAC system is currently being
utilized at the KWTF, and is effectively treating the COCs.
Components of the GAC system a=e readily available and adaptable
to the" CSC OU4 Site.
20
\ J
-------
Costs associated with alternative 4 include the GAC system
design and construction costs. Costs for the installation of an
air stripping unit are not included, as the need of an air
'stripper is not anticipated. The cost breakdown for the 30 year
life of the alternative includes:
-,
. '.. .
- ..' ..' ,- .
. .~'.:.' '''.-r:-...:. .j-;.."\..:~~~.' -..-'.'
:. :::.:: .-;,;;:....:.~-=:-;.;...:::: .-;.: :". .
Capital Costs $1,772,600
Present worth of Annual O&M $2,587,200
Present worth of Annual Monitoring $147,600
=========
Total Present Worth
$4.507.400
Alternative5- Air Strippinq Treatment
, Alternative 5 involves the use of an air stripping treatment
system for addressing the contaminated water from Wells 1.8, 21.,
and 47. Construction of a packed column aeration (PCA) air
, stripping, unit at the Reservoir 4 storage facility would be
necessary. The air stripping'unit would consist of a single
packed tower with forced air blowers and a storage tank. The
contaminated water from the three wells would be collected and
pumped to the packed tower, where water would flow down the
packing,by gravity while the air flows upward. Based upon
previous studies regarding air stripping emissions, it was
determined that VOC emission controls would not be necessary at
this location. The total VOC emission rates were estimated to be
below the rate requiring a State permit (one pound per day), thus
emissions could be discharged directly to the atmQsphere. Actual
emissions would need to be verified and continuously monitored to
ensure compliance. '
The air stripping system proposed for Alternative 5 would be
effective in reducing the VOC contamination from Wells 1.8, 21. and
47, thus the RA objectives would be satisfied. Ai~ stripping has
'been proven to be effective for the removal of organics similar.
to those at CSC OU4, with the added advantage that vinyl chloride
would also be removed from the water. .
Alternative 5 is technically and administratively
implementable. Components of the air stripping technology are
readily available and adaptable to the CSC OU4 Site. .
Construction of the air stripping treatment system would be
necessary in order to implement the alternative. No pilot
~esting would be required, but continued air ~~ssions monitoring
would be critical. .
Costs associated
stripping unit design
include operating and
monitoring.
with Alternative 5 include the 'air
and, construction costs. Annual O&M costs
maintaining the syst~~ as well as routine
21
-------
The cost breakdown for the 30 year life of the alternative
includes: .
Capital Costs .
Present Worth of Annual O&M
Present Worth. of Annual Monitoring
$869,400
$2,9~7,000
$~47,600
---------
---------
. ..-
'",,:'. ...:".::U"'. ..- -. . .
Total Present Worth
$3.934.000
.... . .__0'
V:I:II.
S'tDDIARY OF COMPARATIVE ANALYSIS OF ALTERNAT:rvES
The remedial alternatives developed in the CSC OU4 FS were
analyzed i~ detail using the nine evaluation criteria of the NCP.
The resulting strengths and weaknesses of .the alternatives were
then weighed to identify the alternative for CSC OU4 which would
provide the best balance among the nine criteria. These.criteria
are:
-.
Overall protection of human health and the environment
Compliance with ARARs
Long-term effectiveness and permanence
Reduction of toxicity, mobility, .or volume
Short-term effectiveness
Implernentability
Cost
State acceptance
Community acceptance
Each of these criteria is described and analyzed berow.
Overall Protection of Human Health and the Environment
.. This criterion addresses whether or not' a remedy provides
adequate protection and describes how risks. posed through each
pathway are eliminated, reduced, or controlled.
Alternative 1 provides current minimal protection of human.health
and the environment through the blending program, but would not
in the future. Both Alternatives 3 and 4 provide protection of
human health and the environment by reducing the contamination in
Wells 18,' 21, ~nd 47. Alternative 5 is protective of human
health through the reduction of contamination in well water. .
Protection of the environment is maintained by Alternative 5 as.
long as VOC emissions are within acceptable limits.
Compliance with ARARs
This criterion addresses whether or. not a remedy will meet
all Federal and State environme~tal laws 'and/or provide grounds
for a waiver.
22
-------
Alternative ~ 'is presently in compliance with the ARARs
. established for OU4, but will not provide' compliance in the
future due to the limitations of the blending program. .
Alternatives 3 and 4 will meet the ARARs. With respect to MCLs,
they .will be met at the drinking water tap. Should VC be
detected in excess of. the MCLs, and KWTF capacity is not
sufficient to treat it, an air stripping unit will be added to'
. '.' ~~"t.he.:~AC system~ This will ensure compliance with. all ARARs.
.' . "Altemat'ive . 5 will meet the ARARs as long as air emission
standards are maintained. If the VOC emissions for Alternative S
exceed acceptable limits, the addition of off-gas treatment will
.berequi!ed prior to release. .
It should be noted that the aquifer is being remediated by
actions taken in OUs 1 and 2 and that the remediation is enhanced
by the actions taken in the EPA RMA Off-Post OU1 ROD and this
ROD. For ground-water remediation standards and ARARs
compliance, please refer to the RODs for CSC OUs 1 and 2 and the
above mentioned EPA RMA Off-Post .OU1 ROD.
Lonq-Term Effectiveness
This criterion refers to the abili.ty of a remedy to provide
reliable protection of human health and the enviror~ent over
time. .
No long-term effectiveness is provided by Alternative 1.
. Alternatives 3 and 4 both provide the greatest long-term
effectiveness, since the COCs, with the exception-of VC, are
permanently. removed from the well water and destroyed off-site
through the regeneration of the spent carbon. Alternative 5
provides long-term effectiveness through permanent removal of
contaminants from well water. While the COCs are net permanently
destroyed, they are diluted to acceptable levels after release to
the atmosphere. '.
Reduction of Toxicitv. Mobilitv. or Volume
This criterion refers to the preference for a remedy that
reduces health hazards, the mov~~ent of contaminants, or the
quantity of contaminants at the Site.
Alternative 1 provides minimal reduction in the toxicity,
mobility, and volume of the contaminants through the blending
program. Alternatives 3 and 4 permanen~ly reduce and/or.
eliminate the toxicity, mobility, and volume of the COCs, with
the exception of VC, through the utilization and regeneration of
GAC. Alternative 5 reduces the toxicity of contamination through
. dilution in ambient air.
23
-------
Short-Term Effectiveness
This criterion addresses the period of time needed to
complete the remedy, and any adverse effects to human health and
the environment that may be caused during the construction and
implementation - of the - remedy. -
:_:~:::-.~:,::s:'~~::-:-,: Short-term effectiveness is provided by Alternative ~
-- -----through the blending program. - Alternatives 3, 4, and 5 provide
significant short-term effectiveness as the treatment of the
water from Wells ~8, 2~, and 47 is provided in a relatively short
period of time. No increased risks or exposure to contamination
will occur during implementation. -
- -
ImPlementability
This criterion refers to the technical and administrative
feasibility of a _remedy.- This includes the availability of
materials and services needed to' carry out the remedy. It also
includes coordination of Federal, S~ate, and local governments to
clean up the Site. -
All of the alternatives under consideration are-both
technically and administratively implementable. Alternative ~ is
the easiest to implement as no additional activities _are
required. Alternatives 3, 4, and 5 involve the utilization of
proven -technologies that are readily available. Easements will
need to be obtained for pipeline routes.
Cost
Cost evaluates the estimated capital and operation and
maintenance costs of each alternative in cornDarison to other
equally protective alternatives. Please see-the OU4 FS for- cost
breakdown and evaluation.
Alternative~ has the lowest total cost, as minimal- activity
is required. Among the treatment options I Alternative 3 has the
greatest- capital cost, followed by Alternatives 4 and 5. The
treatment alternative with the greatest O~~ cost is Alternative 5
followed by Alternatives 4 and 3. Total present worth for the
treatment alternatives from the most exoensive to the least
expensive are for Alternatives 4, 5 and-31 respectively. -
State Acceptance
This criterion indicates whether the State agrees with,
opposes, or has no comment on the pre~erred alternative.
\
EPA has involved COR throughout the RI/FS and r~~edy
selection process. The State concurs with EPA's selected
alternative, Alternative 3.
24
-------
Community Acceptance
This criterion includes which components of .the alternatives
interested persons in the community support, have reservations
about, or oppose. At the public meeting and in the comments
received, all have fully supported EPA'S selected alternative.
". Please refer to Appendix A of this document for a St1I[U'[lary of the
.<~:~:~:.~it~en public comments received and EPA responses.
:IX. .
SELECTED 1Z~y
EPA has selected CSC OU4 Alternative 3, connection of SACWSD
Wells 18, 21; and 47 to the KWTF, as the remedy for CSC OU 4~
The remedy for OU 4 is made up of the following components:
connection of Wells 18, 21, and 47 to the KWTF
~"
treatment af well water at the KWTF by granulated
activated carbon to below MCLs (please see table B-1,
Appendix B), in compliance with the EPA Off-Post ROD
regeneration of spent carbon off site in compliance
. with the Off-Post ID1A OUl ROD
,
transmission of treated water to Reservoir 4 for'
storage
quarterly monitoring of Wells ~8, 2~, aRd 47,' and
Reservoir 4 "
The RA for Wells 18, 21, and 47 will continue as long as is
necessary to insure the MCLs are met at the tap. MCLs at the tap
will be achieved via treatment by the KWTF which was constructed
as a r"esult of EPA RMA Off-P9st OUl ROD, dated June .1987..
The selection of this r~~edy is based upon the comparative
analysis of alternatives presented in the previous section. This
remedy provides the best balance with respect to the nine
evaluation criteria, is protective of public health, and will
comply with all identified State and federal ARARs.
For CSC OU4, connection of SACWSDWells 18, 21, and 47 to.
the ~~F will ensure that residents of south Adams County are
provided with adequate drinking water and protected from exposure
to contaminated ground water.
Alternative 1 was not chosen because it is not a permanent
solution and will not comply with allARARs in the future.
~..lte:!:"!lat~.ve 3 was chosen over Alternative 4 because. it is less
costly and Alternative 3 utilizes an exist~ng facility for
treatment and Alternative 4 would require the construction of a
25
-------
i
i .
new GAC system. .Alternative.3 was chosen over Alternative 5
because. it is less costly and Alternative 5 would not destroy
contaminants, but would only. .reduce toxicity by dilution in the
atmosphere. . .
'vc has not been detected in ground water extracted by the
SACWSD municipal supply wells. As mentioned previously, if VC is
:,.:-;'~:;.de~~cted. at quantities in which the KWI'F cannot treat to
. '-:"performance standards (MCLs), 'an air stripper. will be retrofitted
to the KWTF as specified in the provisions of the EPA Off-Post
RMA ROD. .'
x.
STATUTOR.Y DETERMINATIONS
EPA's primary responsibility at CERCLA sites is to select
RAs that are protective of human health and the environment. .
CERCLA also re~ires that the selected remedial action for the
Site comply with applicable or relevant and appropriate
environmental standards established under Federal and State
environmental laws, unless a waiver is granted. The selected
remedy must be cost-effective and utilize permanent treatment
technologies or resource recovery technologies to the maximum
extent practicable. The statute also contains a preference for
remedies that include treatment as a principal element. The
following sections discuss how the selected remedy .for CSC OU4
meet these statutory,requirements. ~
Protection of Human Health and the Environment
The remedy selected for OU4 addresses the exposure or
potential exposure to contaminated ground water through SAOqSD
Wells 18, 21, and 47. Alternative 3 is protective of human health
by ensuring that the water extracted by Wells 18, 21, and 47 used
as part of the municipal water supply is'treated to levels below
MCLs. . .
Attainment of Applicable or Relevant and Appropriate Requirements
All ARARs would be met ,by the selected remedy.
, CSC OU4 were discussed in Section VIII of this ROD.
ARARs for
Cost Effectiveness
EPA believes that the seiected remedy is cost-effective in
mitigating the risk of exposure to contaminated ground water.
Section 300.430{f) {ii} (D) of the NCP requires EPAto.evaluate
cost-effectiveness by comparing all the alternatives which meet
the threshold criteria, protection of human health ~~d the
eITvironment, against three additional balancing criter.ia: long-
'term effectiveness and permanence; reduction of toxicity,
mobillty, or volume through treat~cTIt; and short-term
effectiveness. The selected remedy meets these criteria and
26
-------
produces the best overall effectiveness in proportion to their
cost. The est~ted cost for the selected remedy is $3,3~4,900.
Utilization of Permanent Solutions and Alternative Treatment
Tecbnoloaies or Resource RecoverY Tecbnoloaies to the MaX~um'
Extent Practicable
. .
....:,,':.: .:-..., ':. EPA::.believe~::.the..:.,se~ected rerneq.y represents the maximum
extent to' which':"I;>ermanenF solutions and treatment technologies
can be utilized in a .cost-effective manner for CSC OU4. Of those
alternatives that are protective of human health and the' .
environment and comply with ARARS, EPA has determined that the
selected remedy provides the' best balance of trade-offs in terms
of long-term effectiveness and permanence; reduction in toxicity,
mobility, or volume achieved through treatment; short-term
effectiveness; implementability; and cost, ana also considering
the statutory preference for treatment as a principal element and
considering State and community accept~ce.
. .
," -'
As""mentioned previously, OU4' s primary purpose is to provide
a drinking water supply that meets MCLs. QUs ~ and 2 address the
restoration of the ground water aquifer which is the source of
water for Wells ~8, 2~ and 47. The restoration of the aauifer
will be enhanced by the actions taken in both the EPA RMA Off-
Post OU~ ROD and this ROD.
The selected remedy (Alternative 3) provides a permanent
remedy at minimal costs. Additional costs after connecting Wells
~8, 2~, and 47 to the KWTF include quarterly gro~nd-water
monitoring and annual operation and maintenance costs at the
KWTF. The selected remedy was the. least costly of the.
alternatives that met the threshold criteria.
Alternative ~ does not have a long-term effectiveness and
permanence component. Alternatives 3, 4 and 5 are equal in their
long-term effectiveness.
Alternatives 3 and 4 reduce toxicity, mobility and volume
through treatment equally. These two alternatives remove the
contaminants from.the water via activated carbon. The
contaminants are immobilized through carbon regeneration.
Alternative 5 reduces toxicity in the water via transfer to the
atmosphere. However, mobility and volume are not reduced by this
alternative. Alternative ~ only reduces toxicity by dilution.
All alternatives are equally effective on a short~term
basis. Alternative ~ has the advantage that it is already in
place.
Alternative 1 is the most easily implemented.
the alternatives are equally implementable. .
The rest of
27
-------
Of the viable alternatives, 3, 4 and 5, 3 is the most cost
effective and least costly in the long run. .
Long-term effectiveness and permanence and cost were the
most decisive of the above 5 criteria in selection of the remedy.
The State of Colorado concurs with selection of Alternative 3.
. .".- .';'.. '...0 ." ~:. ..
".... .... _0"'. ,- -. .
.. .
Preference for Treatment as a Princiual.Element
. The selected remedy satisfies the statutory preference for
treatment as a.principal element.. No principal threat exists in
CSC OU4. A principal threat is defined as. material that includes
or contains hazardous substances, pollutants or contaminants that
act as a reservoir for migration of contamination to ground.
water, to surface water~ to air, or acts as a source for direct
exposure. Contaminated ground water generally is not considere~
to be a source material. An exception to this is the presence of
NAPLs in ground water (see Superfund publication 9380.3-06FS,
Nov.ember ~991) . . .
Documentation of Siqnificant Chanqes
There. are no significant changes to EPA's preferred
alternative as presented in the OU4 Proposed Plan. EPA's
preferred alternative is the connection of SACWSD Wells 18, 21
and 47 to the KWTF.. .
28
-------
REFERENCES
Black & Veatch 1989. South Adams County Water and sanitation
District, Organic Contaminant Ground water Quality' Information.
. B & V Project 13720.167.
CDM Federal Projects Corp. 1990. Final Remedial Investigation
, . .: Report, Chemical Sales Co. Operable Unit 2, Chlorinated. .
, "Hydrocarbon Ground water Plume. Document Control No. 7760-004-
RI-BLFT. .
URS Consulting 1992. Feasibility Study Report - Chemical' Sales
Co. Site, Operable Unit 4.
USEPA 1987. Record of Decision - EPA's Off-Post Rocky Mountain
Arsenal Operable Unit 1.
, '
,USEPA 1991. Record of Decision - Chemical Sales Co. Site,
Operable Unit 1.
USEPA 1991. Record of Decision - Chemical Sales Co.' Site,
Operable Unit 2 and Operable Unit 3.
29
-------
~ ,
APPENDIX B
37
-------
I
"
.~ "
TAELE B-1
)
_.. .~.. -. . -~
Summary of };RARs:
Chemical-specific
"
I '
, Potential to \
"
.. " be
: ..
Standard. Applicablel
Requirement, .. ' , Relevant
Criteria, or' : ,and
\ Umilation Citation Description Appropriate Comment
!
\ \ " l ,\
FED~ARARs j,
i
S~fe Drinking W~ter 42 use ~ 300g Establishes regulation.5 governing See below See below
Act the quality of water that is being .
provided diredy to 2S or Clore
people. or that wiil be supplied to
15 or more ~rvice COt\I\~ON.
National 40 crR Part 141 Establish~ health-based Yes Tne~ standards are
Prima ry suncara., for public: watt't supply applicable since the cse
DrWcing syste%XU (maximum cont3t:'\inant OU4 alluvial aC!,uifer is
Water levels). - used. as a public: drinking
5 ta nd.a. ra., water source. Table 1-4
provides action levels for
the cse chemicals of
concern.
N~tional 40 CFR Part 143 Establishes welhr~b.ued No These standarcU are
Second.a.ry stand.a.rds for public: water supply neither applicable nor
Drinking systems (secondary Ma..s) relevant and appropriate
Water sinC2 there are no
Standards SoeQJndary standards 'for
contaminants of concern.
Secondary MCLs relate to
welfare concerN and not
contamination.
Maximum 40 CFR ~ 300.~ Establishes cirinkil'Ig water quality No . " For tho~ chemicals of
Contaminant Pub. L. No. 99- goals set at levels of nO known or concern at cse with
Level Goals 339 a:\ticipated adve~ health effec:u, established MaGs (vinyl
(MO-Gs) 100 Stat. 642 with an adequate margin of chloride. tric.~loroet."ane.
(1986) safety. ,and 1.2-dichloroethane).
MaGs are uro and
t."erefore not ~.
MaGs are potential TBCs
, for c."e1I\icats without
ARAR.s.
41911.04 - Den
Appendix. A:fina I:dm.
38
, J
-------
I
.. \
SummAry
TABLE B-1
(Continued)
of ARARs: Chemical-specific
or ...
I I
... Potential to
'. . be'
Sbndard;. . Applic:a.blel
Requirement, Relevant
Criteria, or and
Limitati"on' Citation Description Appropriate COII\II1.en~
OeU\ W~ter Act \ csc ~ ~ \ See below See below See below
1251-1376
Water ~ aR 131 Sets aiter\.1 for :water quality, Yes These 5tandar~ are I
Quality ba$ed on toxicity to aquatic. potential\y applicable and
Criteria organisms and human health. relevant and appropriate
(WQq Guidance to be used by states in since the CSC QU;\ anuvial .
setting their water quality aquifer is a C"..tITent public
standards for s"Urface water. driNOrlg water source.
CERa.A 9 121 specifically
provides that WQCs may be used
as relevant and appropriate
standards for groundwater if
adjusted. or surfac.e water.
Resource COn.Mrv~tion P .L'. 94-580 Establish~ regulations governing See below \ s~ be'ow
U\d Recovery Act .md as amended ; the dispo:s.al and treatment of
RegulatioN! ~~O~2~O~~' . listed or charac:t.eri:stic wastes.
Land .w aR 9 268 Prohibits land disposal of No . Land disposal restrictions.
Dispo:s.al hAurdous waste unless the are an ;...RA::R 0 nly if
RestrictiolU wastes are treated to particular remedy involves disposal
OJncentratiolU. of COOltamiNted material
Oe.m A1r Act 42. use 9 ! Establishes regulations to protect See below See below
7401-76-U and enhance the quality of the
:ution's air re::sour~.
National ~ crR 61 Establishes emission standards Yes These regulations are
E:nission for h.turdous air poUutantS. potential\y applicable and !
Standards for . relevant and appropriate if
Huudous .tir emissions oc.c:ur (air
Air stripping alternative).
ponutants
(NESHAP)
. .
41911.04 - Den
Appendix.A:final:dI:n
I
39
-------
Summary
TABLE B-1
(Continued) -
of ARARs: Chemical-specific
.
... .-."' -- -~- .
'-'--..--
./.
... --'-."'-
-, .'- ..'
--,
. ., '. .-
.. - ..
.. -' .-.-"" ...
Potential to I II
-, be -'
Stanchrd, .. Applicable!
"
Requirement, Relevant
_Criteria, or" and
Limitation Cilation Description - Appropriate Comment
STATE ARARs
Colorado Primary 5 CCR 1003-1 Establishes drinking water Yes These standard.s are
Drinking Water Part I. Title 25 regulations (MQ..s) for public potentially applicable since
Regula tions C.R-S. water systemS and allows the - the CSC OU4 aUuvial
state to assume responsibility for aquifer is used as a public
the eniorcement of State DriI\king c!rit\king water source.
Water Act (SDW A) standard.s.
Colorado Wolter 5 CCR 1002.8 Establishes a system to cLassify See below Tnese standards are
Quility Control -Act Part II, Title 25 . gToundwater and adopts water applic::lble if they are more
C.R.S. Sections quality standards to protect stringent than federal
25-8-202, 25-8- existing and potential beneficial standards. Table 'B-4:
203, 25-8-204 users of gToundwat.ers. .- provides action levets for
the CSC che:nicats -of
concern.
The Basic 5 CCR 1002.8, Pertains to direct discharges to Yes These standard.s are
Standards for - Section 3.11.0 groundwater. applicable if they are more
Groundwater stringent than federal.-
standard.s. Table B-4'
: provides action levels for
the CSC c:.lteInicais of
co ncern.
41911.04 . Dell
Appendix.A:fir\aI:dm
40
-------
~. ..
TABLE B-2
Summary of ARARs:
Location-specific
J
.-
.. . .- '.. .-' .
-..'. .
. ... ....-.
.. ..
Potential to
be
Standard, Applia.ble!
Requirement, Relevant
Criteria, or - and
"
Limilation Citation Descrlption Appropria.te Comment
\ FEDERAL ARARo I I [ \ I
National Historic 16 U.S.C. ~ 470 Requires federal agencies to take No The alternatives uz:'der'
Preservation Act 40 CFR g 6.3Q1 into account the effect of any review will r.ot affe~ any
36 CFR g 89QO federally assisted undertaking or district, site, building,
licensing on any district, site, st:Ucture, or object listed
. building, structure, or object on, or eligible for, the
that is included in or. elig"1."ble for National Register of
inclusion in the National Historic Places.
Register of Historic Places. -
Archeologio.1 and Establishes procedures to -
16 U.S.c. ~469 No The altematives under
Historic Preservation 40 CFRg 6.301(c) provide for preservation of review wm not affect
Act historical and archeological data historical or archaeological
which might be destroyed data.
through alteration of terrain as a
result of a federal construction
project or a feden\1y lice~
activity or program.
Historic Sites, Buildings 16 U.5.C. H 461- Require:! federal agencies to No The altemative:! under
and Antiquities Act 467 consider the existena; and review w\1\ not affect any
.w CFR ~ 6.301(a) location of landmar\cs on the naturallandI:nark.
National Registry of NatUral
Landmarks to avoid undesirable
im~c:t5 on such landmarks.
..
Fish and Wild1iIe 16 U.5.c. 9 661- Requires consultation when a No There are no natural
Coordirlation Act 666 fede"1 department or agency streams or other water
40 CFR ~ 6.301(g) proposes or authorizes any bodies impacted by the
modification of any stream or '. pro je<:t.
other water body and adequate
provision for protection of fish
and W\ldliIe r~urcP.S.
41911.04 - Den
Appendix.A:final:d."I'\
41
, }
-------
S umma.ry
TABLE B-2
(Continued.)
of ARARs: Location-specific
!7 ~
------.---
. .----'
-.'
-
. ... ,., '. .. '
Potenual to .
,.. be ' '
Slandard, Applicable!
, Requirement, - Relevant
Criteria, or '. and
- .. .
Limitation Citation Description ' . Appropriate Comment
Endangered Species Act 16 U.S.C. 1531 Re
-------
UR5 CONultanu. Inc.
ARCS, EPA RegioN VI, vn and.vm
Contract No: 68-W9-0053
"..
summary
TABLE B-2
(Contin~ed)
of ARARs: Location-specific
.. .. ~, -' -
': -::.' '.:::: ".: - :; '-. ". ~
4;; :~
..' Potential to
be
Su.ndard; " Applia.bleJ
Requirement, , Rel~vant
Critem, 'or and -
. Limitation Citation Description Appropria.te Comment
Na tiona I \ 16 USC 668; 50 Restricts activities within a No Tt\e~e are no wildlife 1
. Wildlife CFR'27 National Wildlife Refuge. refuges on-sile or adjacent
Refuge to the sileo
System
Wild U\d S<:enic River 16 USC 1'271; 40 Prohibits adver$e effecu on a .\ No \ There is nO scenic -river in
Act CFR 6.30:;:(e) scenic river. the area.
Coastal Zone 16 USC H51 Requires coastal activities to be No The area is not in a coastal ~
Management C'Onducted in accordan~ with zone.
... . state-approved management
program.
.. " \
' ... '. -
. . ,. "
,STA TE:ARA.R$'. ..
.." , : ..
Colorado State CR.S. Sections Sites within state or federal 'No The alternatives under
Historical Society 24-80-'201, 202. historic preservation areas wm review win have no effe<::
211; SectioN 24- be required to. preserve historic on stale or federal historic
801-101. 102. 103. . ch&racter. preservation areas.
104. 108 ..
Requirements for Siting 6 ca 1007-2, Pt Get:1logidhydrologic .c:cnditio'ns No No on-site haz..ardo\lS
of Haurdous Waste II, SectioN 2.1, must assure waste isolation from' waste disposal faaiity is
Disposal Sites 2.4. and 1..5. exposure pathway, from 1000 contemplated.
years. Siting must assure short
and long term prot~on of
human health and environment.
Colorado Haz..ardous 6 CCR 1007-3 Siting is restricted in vicinity of No No on-site haz..ardous
Waste Management recent faulting. No hn.udous waste disposal faa1ity is
Regula tiON waste disposal an Q
-------
: Summary
TABLE B-2
(Continued) . .
of ARARs: Locatio~-specific
"':-"
i .
.. ..~._-~
.,
.. .
,-
.'
Potential to
be
Standard; . Applia.bleJ
Requirement~ Relevant
Criteria, or and
Limitation Citation Description Appropriate Comment
Regulatior\S Pertaining 6 CCR 1007-2. Siting Inust maximize wind No No on-site hazardous'
to Solid Waste Disposal SectiolU 1.3.2. protection and Inini:ni:e waste disposal faciiity is
Sites and Faci1ities 2.1,2.2. 2A, 4.1, upstream drainage area. No conteInpia ted.
6.1. solid waste disposa1 can O<:C".lr in
a l00-year floodplain. Disposa1
into or below surface water. and -
groundwater is prohibited.
Impoundment design is
control1ed by a site's 10cation in
re!a tion to the upper-tI\ost
aquifer and by water quality in
that aquifer.
41911.04 - Den
Appendix.A:final:dm
44
, ,
-------
~ .
TABLE B-3
Summary. of ARARs:
Action-specific
. .
I.
---- -. - ----
I I
Potential to
be
Stmdards, Applicable!
Requirement;.. Relevant
Criteria. or and
Limitation Criteria Description Appropriate Comment
FEDERAL A.RARs
OccupatioNI Safety 29 GR 1910 Regulates worker health Yes Health. and safety
and Health Act and safety. requirements of the
(OSHA) Act apply to an
re!:\eciial actions.
Hazardous Materials 49 U.s.C. H 1801- Regulates transportation No Applicable only if an
Transportation Act 1813 of hazardous materiais. alternative under
review would involve
.. transportation of
hazardous C\aterial!
Hazardous Materials 49 CFR H 107,171- Regulates transporution -
No Applicable only if an
.Transportation 177 of haurdous materials. alternative under
Regulations review would involve
transportation of
hazardous materials
Resourct! Conservation 40 CFR H 260-270 Regulates generation. See below See below
and Recovery Act and treatment, storage and
Regubtiona disposal of hazardous
waste.
Land 40 CFR ~ 268 Prohibits land disposal No Applicable only if an
Disposal of haurdous waste alternative under
Restrictions unless the w:aste5 are review would involve
treated to particular the treatment, storage
c:oncentra tions. . or disposal of
haurdous wastes
Underground Injection 40 CFR H 144-H7 Requirements far No Not applicable or
Co\'\trol Program underground injection relevant and
by wells. Promulgated appropriate since the
under Part C of the Safe reinjection of
Drinking Water Act. groundwater is not
being consider~as a
remedial action for the
CSC OU4 site.
411;11.1:14 . Den
A ppendix.A:fina1:dm
45
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. -.- -_.
- .
5 tanda.rds,
Requirement,
Criteria or
Limitation
OUZ\ Water Act
National
Pollution
Discharge
Elimina tion
System
. (NPDES)
OUZ\ Air Act
Natioti.al
Ambient Air
Quality .
Standards
.(NAAQS)
. .
. ..
STA TI: Ai{ARs,.
Rules and Regulations
Governing the Trans-
portation of Hazardous
Materials Within
Colorado
Colorado Hazardous
Waste Act
Hazardous Waste
Regulations
41911.c..;. - Den
Appendix.A:final:d.m
_I
Summary
Criteria
33 USC H 12.51-1376
40 CFR 403
41 USC 9 74Q1-76-U
40 CFR 50
I 4 CCR 723-18, HMT .
1-9
C.R.S. Title 25,
Article 15
6 CCR H 2~267
TABLE B-3
. (Continued).
of ARARs: Action-specific.
.. .
Description
See below
Regulates the
unpermitted disdlarge
of any pollutant or .
combination of
pol1utants to waters of
the U.S. from a point
source.
\ See below
Establishes air quality
standarcl.s for regula ted
air pol1utants.
. -
p'
...
Establishe5 specific
requirements for the
transportation of
hazardous materiai5,
especiaUy regarding
labening and plaarding.
Regulates generation,
treatment, storage and
disposal of haurdous
waste.
46
Potential to
be
Applicable!
Relevant. .
a.nd
Appropriate
See below
No
See below
Yes
..
. .
p
..
p
..
p
No
No
-
~ .
i
-----.- ----.- .~)
Comment
See below
The NPDES provisions
of the Oean Water Act
are not applicable or
relevant and
appropriate since there
is no current or
proposed point source
discharge from the
site.
See below
J
-
The N AAQS
YlolilCi . 'be
~ppiiCable if air
emissions 0= (air
stripping alternative)
which would impact
the ambient air
quality.
. .
..
..
..
.Applicable only if an
alternative under
.review would involve
transportation of
ha:z.ardous materials .
Applicable only if an
alterNtive under
review would uwolve
.~~e treatment, storage
or disposal of
hazardous wastes.
-------
Summary
TABLE B-3-
(Continued)
of ARARs: Action-specific
~ -
.-
.-
. ...- ._0.' -...-
I I
Potential to
be -
Standards, Applicable!
- Requirement, Relevant
Criteria or and
Limi La. non Criteria Description Appropriate Comment
Colorado Noise- c.R-S. ~ 25-12.103, Establishes standards for - Yes Potentially relevant
Abatement Statute. controlling noise. and appropriate
Seo:io~ 25-12-101 during construction
through 108 activities.
Colorado Wildlife 2 CCR Sections 3:)-(r Prohibits s~cific actiolU Yes Potentially relevant
EnIorce%:\ent and 101 through 105. 108 in order to protect and appropriate for
Penalties through 111. 113 wildlife. protecting WIldlife
through 130. near t..'Ie site during
- construction acti\~ties.
Wildlife Coaunission 2 CCR 406-{). Articles Establish~ specific Yes' Potentiaily relevar.t
Regula tions I. m. IV. V, VI, VU, requirements for and appropriate for
VITI, IX, X, XI protection of WIldlife. protecting wildlife
- near t..l"e site during
constrUction activities.
Oosure. 6 CCR 1007-3. H 262 Colorado HazardoU5 No Regula tions to be
Transportation. On- and 264 Waste Management reviewed if
Site Dispos.al of Regulations governing alternatives involve
Treatxnent Residu~ closure of hazardous disposal of hazardous
waste TSD facilities. , waste on the site or
transportation of removal and dispos.al
hazardous wastes and off site.
on-site disposal of
treatment residue.
Colorado Air Quality 5 CCR 1001 Sei! below See below See below
Control Act
Common 5 CCR 1001 Establishes intent. of air . Yes Applicable if air
Pro V'i.sio ns emission control emissions occur (air
Regulation regulations. stripping alternative).
41911.04 - Den
- Appendix.A:final:dm
47
\ 7
-------
"I
Summary
TABLE B-3
. (Continued)
of ARARs: Action-specific
. j ~ \.
!
\ -
" .
I I
Potential to
be ..
S tand.a.rds, . ..
Applicable!
Requirement, Relevant
Criteria or and
. Limitation Criteria Description Appropriate Comment
Stationary 5 CCR 1001-5. Sec. Source cannot cause an Yes Non-attainment area.
Emissions IVD exceedance in any The site could be
Sources; . attainment area of any considered a major"
General NAAQS. source if it emits more
Controls for than 100 tonsfyear of
Remedial CO or YOCS. Applies
Activities to air-stripping
activities.
5 CCR 1001-5 Sec. Source cannot interfere Yes Non-at'.
-------
TABLE B-4
. .
. -Performance Standards for Chemicals
of Concern
I Chemical of Concern I Action Level (ppb) I ARARs I
PCE I 5 I Me..w CFR 141 \
TCE 5 ' Me. 40 crR 141
TCA 200 Me. 40 CFR 141
DCA 5 Me. 40 C'R 141
1, 1-DCE 7 \ Me. 40 CFR 141 I
1, 2-DCE (cis and tran.s isomers) 70 \ .Colorado B.asic Standard for . \
Groundwa ter
VC 2 Me. 40 C:R 141
\ I
BZ 5 Me. 40 CFR 141 \
The Ma.:s from 40 CFR 141 are as fonows: 70 ppb for cis.-1.1-DCE. 100 ppb for t:r2n.s.-1.2-DCE. The Me. from tr.e
Colorado Basic: Standard.5 for Groundwater for both the cis and trans isomers i3 iO ppb. Th~ state standard is II\ore
stringent and, therefore. takes pre<:edence. .
41=111.04. Den
Appendix.A:final:d.m
49
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..
. .
APPENDIX C
50
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STATE OF COLOMDO
COLORADO DEPARTMENT OF HEALTH
Dedicatl?d to protecting and improving the health and
environment of the people of Colorado
4300 Cheny Creek Dr. 5. Laboratory Building
Denver, Colorado 80222.1530 4210 E. 11th Avenue
Phone (303) 692.2000 Denver, Colorado 80220-3716
(3031691-4790-.
December 28, ~992
Mr. James J. Scherer
Regional Administrator
US EPA vm RA
999 18th Street, Suite 500
Denver, Colorado 80202-2466
"
Roy Romer
(..., Govemof)
-.. ~.. ~"..."
::.-=; :Pa~oIan. MD. MPH
.-::; 'fx~e DirectOl'
;::; :_- .~
I. ..''''
~F
j'.... ).
c:.
~ ~..: ::~...
. f:"'08::
~p
.:....:. _..;
':-'-:
....... .
Subject: Chemical Sales Co. Superfund Site OU 4 Record of Decision
~~t1
Dear. ~rer:
. .
The State of Colorado has reviewed the Record of Decision (ROD) for the Chemlcal Sales
Company Superfund Site (the Site) Operable Unit 4 and concurs with the United States
Environmental Protection Agency's (EP A) decision to select Alternative 3 as the remedy.
Implementation of this remedial action will assist with ground-water restoration.
As part of this concurrence, the State of Colorado requests that EP A maintain a strong and diligent
effort towards the evaluation of contaminants from all viable responsi1Jle parties for the Site. This,
we believe, should include strong efforts to secure payment for both capital construction costs and
additional operation and maintenance costs required to implement this action, as well as efforts
to address ground water in the geographic area of Operable Unit 4. Absent such efforts the State
of Colorado may be unable to enter into a formal contractual agreement to finalize the remedial
action. .
We look forward to a continued strong working relationship during the Remedial Design and
Remedial Action phases for this Operable Unit as well as during the cleanup of the sources
(Operable Unit 1) and the alluvial aquifer (Operable Unit 2).
Sincerely,
~
f#v1
Thomas P. Looby
Director
Office of Environment
cc:
David C. Shelton, CDH
Jim Lewis, CDH
Robert Eber, AGO
Jim Berkley, EPA
John Barth, EPA/ORC
51
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