United States
Environmental Protection
Agency
Office 01
Emergency and
Remedial Response
EPAlRODJR08-91 1053
September 1991
CCSfIf!
~ If'2.. -fC~ Cf 04
&EPA
Superfund
Record 01 Decision:
v
Anaconda Smelter, MT
'ttazardousWasfe .~
information..... Re8Ourcec...C8t\fer.
us EPA.ReQJon 3 .
, PhllGde1phlo#PA 19107
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S0272.101
REPORT DOCUMENTATION 11. REPORTNO.
PAGE EPA/ROD/R08-91/0S3
1 ~
3. Redplenl'a ACC888Ion No.
4. TItIa MIl SWtItIe
SUPERFUND RECORD OF DECISION
~aconda Smelter, MT
'Second Remedial Action
7. Aulhor(a)
i
5. Report Date
09/23/91
&.
8. P8rfonnlng Organization RepI. No.
8. PiIt10nnlng Orgunlzatlon Name and AcId",..
10. ProjectfTuklWork Unit No.
11. Contraet(C) or Grant(G) No.
(C)
(G)
12. ~ng Organization Name and Addreu
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report . PerIod Covered
Agency
800/000
14.
15. Supplementary No-
16. Abatract (Umlt: 200 worda)
The 6,000-acre Anaconda Smelter site is a former copper and ore processing facility
in Deer Lodge County, Montana. Land use in the area is predominantly residential.
The site is bounded on the north and east, respectively, by the Warm Springs Creek
and Mill Creek, both of which are potential sources of drinking water. From 1884
until 1980 when activities ceased, the site was used for ore processing and smelting
operations. Flue dust was generated as a by-product of copper smelting operations.
fhe majority of flue dust that was generated was reprocessed, and the remaining
portion was stockpiled at nine locations on and around the site. In 1988, EPA
conducted an investigation to determine the nature and extent of the flue dust
contamination. A 1988 ROD addressed the Mill Creek Operable Unit (OU1S) and
documented the relocation of residents from the community surrounding the smelter
site as the selected remedial action. This Record of Decision (ROD) addresses the
Flue Dust Operable Unit (OU11). Subsequent RODs will address further site
contamination in adjacent soil, ground water, and surface water. The primary
contaminants of concern affecting this site from the flue dust materials are metals
including arsenic, cadmium, and lead.
(See Attached Page)
17. Document Analyua L Deacrtptora
Record of Decision - Anaconda Smelter, MT
Second Remedial Action
Contaminated Medium: debris
Key Contaminants: metals (arsenic, cadmium, lead)
b. IdentifleraJOpen-EndecI T8m18
c. COSA TI FIeIdIGroup
18. Avlllabiity Statement
18. Seculty CI- (Thla Report)
None
20. Security CI- (Thla Page)
Nnn~
21. No. of Pagea
202
22. PrIce
See ANSl-Z38.18
See /Mtrucllona on Rewrae
(Formetty NTI~I
Department of Commerce
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EPA/ROD/R08-91/053
Anaconda Smelter, MT
Second Remedial Action
Abstract (Continued)
The selected remedial action for this site includes excavating a total of approximately
316,500 cubic yards of flue dust from the nine flue dust locations and treating the
dust onsite using cement/silicate based stabilization; disposing of the treated
residuals in an onsite engineered repository, which will include a soil or clay liner
and a leachate collection system; conducting air and ground water monitoring; and
implementing institutional controls including land use restrictions, and site access
restrictions. The estimated capital cost for this remedial action is $25,338,000, with
an annual O&M cost of $10,000.
PERFORMANCE STANDARDS OR GOALS: The treatment levels of flue dust cement/silicate
based stabilization will render the material non-hazardous by meeting RCRA TCLP
regulatory limits, and include levels that will limit leaching of contaminants to
ground water to arsenic 5 mg/l, cadmium 1 mg/l, and lead 5 mg/l.
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RECORD OF DECISION
ANACONDA CO. SMELTER NPL SITE
FLUE DUST OPERABLE UNIT
ANACONDA, DEER LODGE COUNTY, MONTANA
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY.
SEPrEMBER 1991
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2.0
3.0
4.0
5.0
6.0
7.0
TABLE OF CONTENTS
PART I:
THE DECLARATION
Site Name and Location
..... ....... .......... ..............
Statement of Basis and Purpose.. ........ .... .... ..........
Assessment of Site
................ ...... .... ..............
Description of the Remedy....... ...... ....................
Statutory Determinations .... .... ..... ... .... ..............
PART II:
THE DECISION SUMMARY
1 . 0
SITE NAME, LOCATION AND DESCRIPTION ... ...............
SITE HISTORY AND ENFORCEMENT ACTIVITIES ..............
2. 1 Site History....................................
2.2 Response History...... ........ .... .... ..........
2.3 Enforcement History... ........ ... ...............
HIGHLIGHTS OF COMMUNITY PARTICIPATION ................
SCOPE AND ROLE OF OPERABLE UNIT
.... .... ..............
SUMMARY OF SITE CHARACTERISTICS .... ..................
5.1 Flue Dust Characteristics ...... ..... ............
5.2 Environmental Releases ........... .... ...........
SUMMARY OF SITE RISKS ...... ..........................
6.1 Contaminants of Concern ....... ..................
6.2 Exposure Assessment .............................
6.3 Toxicity Assessment ... ......... .................
6.4 Risk Characterization. ........ ..................
6.5 Environmental Risks... ............ ..............
DESCRIPTION OF ALTERNATIVES ........ .................. 17
7.1 Alternative NO.1...........................'.... 18
7.2 Alternative NO.2............................... ",18
7.3 Alternative NO.3............................... 19
7.4 Alternative NO.4............................... 20
7.5 Alternative NO.5............................... 22
7.6 Alternative NO.6............................... 24
Page
"
'J
2
3
3
4
5
6
7
8
8
9
1 1
1 1
1 2
1 3
1 5
17
C>
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8.0
9.0
10.0
EVALUATION OF ALTERNATIVES ............ ...............
8.1 Overall Protection..............................
8.2 Compliance with ARARs . .......... ................
8.3 Long-Term Effectiveness and Permanence ..........
8.4 Reduction of Toxicity Mobility or Volume
of Contaminants Through Treatment .............
Short-Term Effectiveness .......... ..............
Implementabili ty ................................
8.5
8.6
8.7
8.8
8.9
Cost. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sta te Acceptance................................
Community Acceptance ............................
THE SELECTED REMEDY..................................
STATUTORY DETERMINATIONS .. ...........................
10..1 Protection of Human Health and the Environment.
10.2 Compliance with Applicable or Relevant
and Appropriate Requirements .................
10.3 Cost Effectiveness .............................
10.4 Utilization of Permanent Solutions and
Alternative Treatment Technologies or
Resource Recovery Technologies to the
Maximum Extent Practicable .... ...............
10.5 Preference for Treatment or a Principal Element
ATTACHMENTS TO PART II
ATTACHMENT 1 -
APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS, STANDARDS, CONTROLS, CRITERIA, OR
LIMITATIONS FOR ANACONDA SMELTER SUPERFUND SITE,
FLUE DUST OPERABLE UNIT
ATTACHMENT 2 -
"
TREATABILITY TESTING DATA RESULTS
Page
25
25
26
26
27
28
28
29
29
29
30
36
36
36
37
37
38
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2.0
3.0
PART III
RESPONSIVENESS SUMMARY
1 . 0
Overview
. . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background on Community Involvement... ........ .......
Summary of Comments Received During the Public Comment
Period from the General Public, Artech and ARCO ......
PART A:
GENERAL PUBLIC COMMENTS/RESPONSES
A-1
General Public Written Comments ............
A-20ral Comments/Response from July 23, 1991
Publ ic Meet ing .............................
PART B:
ARTECH COMMENTS/RESPONSES
B-1
General Summarization of Comments/Responses
B-2
Specific Comments ..........................
B- 2 . 1
Ge n era 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-2.2
Cashman Process Residue Toxicity.....
8-2.3
Supplemental Treatability Testing....
8-2.4
Optimization Testing.................
8-2.5
Phase II Treatability Testing Report
8-2.6
Long-Term Stability Study..... .......
8-2.7
Remedial Investigation/Feasibility
Stud y ...............................
8-2.8
Proposed Plan........................
PART C:
ARCO COMMENTS/RESPONSES
C-1
General Comments...........................
C-2
Ri sk Assessment............................
C-3
AR AR 5 ......................................
ATTACHMENTS TO PART III
At tachment 1~
Attachment 1
ARCO's Written Comments .... ...................
EPA Responses to ARCO Comments on the Baseline Risk
Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Page
2
4
4
6
1 0
16
16
18
, 9
24
24
27
29
32
38
..4 O.
40
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Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
LIST OF TABLES
Location and Source of Flue Dust, Flue Dust Volume
and Tonnage Estimates
Summary of Flue Dust Constituents
EP Tox Analyses for Composite Flue Dust Samples
Comparison of EP toxicity Data to Regulatory Limits
Screening of Chemicals
Summary of Human Exposure Parameters
Summary of Estimated Human Health Risks from Arsenic,
Cadmium and Copper
Summary of Alternatives
Table 10 Comparative Analysis of Alternatives
Cleanup Evaluation Criteria
Table 11 Estimated Net Present Work Analysis
Table 12 Cost Estimates for Alternative 4
Figure 1
Figure 2
Figure 3
. Figure 4
Map 1
LIST OF FIGURES
Anaconda Smelter Site Location
Anaconda Smelter NPL Site
Conceptional Model of Contaminant Transport and Human
Exposure in the vicinity of the Anaconda Smelter
Location of Onsite Repository
MAPS
Flue Dust Locations
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RECORD OF DECISION
PART I:
THE DECLARATION
ANACONDA CO. SMELTER NPL SITE
FLUE DUST OPERABLE UNIT
ANACONDA, DEER LODGE COUNTY, MONTANA
',--;.
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SEPTEMBER 1991
v
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RECORD OF DECISION
PART I:
THE DECLARATION
SITE NAME AND LOCATION
Anaconda Co. Smelter Site
Anaconda, Deer Lodge County, Montana
Operable Unit 11 - Flue Dust
STATEMENT OF BASIS AND PURPOSE
This decision document presents the remedial action for the
Flue Dust Operable Unit of the Anaconda Smelter Site in Deer
Lodge County, Montana, selected by the U.S. Environmental
Protection Agency (EPA) in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and the National Contingency
Plan (NCP).
This decision is based on the administrative record file for
the Flue Dust Operable Unit of the Anaconda Smelter Site. The
Administrative Record Index and copies of key documents are
. available for public review at the Hearst Free Library located on
the corner of Fourth and Main in' Anaconda, Montana. The complete
administrative record may be reviewed at the offices of the U.S.
EPA, 301 South Park, Federal Building, Helena, Montana~
The State of Montana supported the remedy selected in the
proposed plan and it is anticipated that the State will concur
with the selected remedy in this Record of Decision (ROD).
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 ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
The Flue Dust Operable Unit is the second remedial action to
be taken at the Anaconda Smelter site. The first action was
taken at the Mill Creek Operable Unit which involved the
relocation of residents from the community of Mill Creek. The
Flue Dust Operable Unit addresses one of ~he principal threat
wastes (flue dust) remaining on the Anaconda Smelter site. This
action addresses flue dust at the nine discrete source areas on
the Anaconda Smelter site .through removal, treatment and
containment. Future operable units will address remaining wastes
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on the site. Remedial and removal actions on several of these
future operable units are already in progress.
The major components of the selected remedy include:
Removal and treatment via on-site cement/silicate based
stabilization of approximately 316,500 cubic yards of
flue dust material located on Smelter Hill;
',,:
Disposal of treatment residues in an on-site engineered
repository; and
Long-term monitoring and institutional controls
including site access control.
STATUTORY DETERMINATIONS
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
remedial action, and is cost effective. This remedy utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable and satisfies the statutory preference
for remedies. that employ treatment that reduces toxicity,
mobility, or volume as a principal element. Because this remedy
may result in hazardous substances remaining on site above
regulatory or health based levels, a review will be conducted
within five years after commencement of the remedial action and
every five years thereafter to ensure that the remedy continues
to provide adequate protection of human health and the
environment.
9,liJ/? I
Date '
J k W. McGraw
A ting Regional Administrator
Region VIII, U.S. EPA
'J
2
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RECORD OF DECISION
PART II:
THE DECISION SUMMARY
v
ANACONDA CO. SMELTER NPL SITE
FLUE DUST OPERABLE UNIT
ANACONDA, DEER LODGE COUNTY, MONTANA
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SEPTEMBER 1991
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RECORD OF DECISION
PART II:
THE DECISION SUMMARY
1 . 0
SITE NAME, LOCATION, AND DESCRIPTION
"
The Anaconda Smelter Superfund site (Fig~re 1) is located in
southwestern Montana at geographic coordinates N46, 07.7', Wl12,
53.9', The site is situated in and adjacent to the community of
Anaconda in Deer Lodge County. The site is bounded by the
Anaconda-Pintler mountains to the south and the Flint Creek
mountains to the northwest and is located in the southwestern
part of Deer Lodge Valley at an elevation of approximately 5,400
feet above sea level.
The Anaconda Smelter site was used for the processing of
copper and associated ores from 1884 until approximately
September 1980. This site includes several inactive smelting,
refining and tailings disposal areas. A series of large, unlined
tailings and wastewater treatment ponds, including the Anaconda
and Opportunity pond systems, extends seven miles eastward from
the Smelter to the neighboring community of Warm Springs.
Numerous other smaller ponds and slag piles also are present.
The site (Figure 2) encompasses more than 6,000 acres.
Flue dust was generated as a by-product of copper smelting
operations and contains metals such as copper, iron, arsenic,
cadmium, and lead. The majority of the flue dust generated on
Smelter Hill during facility operation was reprocessed. However,
approximately 316,500 cubic yards remain stockpiled at nine.
locations on and around Smelter Hill (Map, cover). Although the
Smelter is closed, flue dust stored at several locations on the
property continues to be a source of environmental contamination.
Some of the 316,500 cubic yards of flue dust has been
consolidated into a structure known as the interim Flue Dust
Storage (FDS) facility and flue dust has also been contained in
the collapsed Main Flue which extends down Smelter Hill from the
stack. The remainder of the flue dust is present at seven other
site locations on Smelter Hill. Each of the nine flue dust site
locations are listed below.
Site Location
Bradley Ponds
Main Flue
Thickener
Area Cut
Coal Pile Tracks
Miscellaneous Piles
FDS Facility
Switchback
Iron Ponds
Map Area
7a, 7b
5
2a
2b
la
1c
1b
ld
3a
Designation
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"
['
('-;
_~'_r"""""~"_I.._"'''--..~-.r~_.~....~~-...- "".aa.-'''''''''''''~~~II'~-n..It.~,...~...
Montana
.. A~aconda:
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,
I
,
....
-,
,
,
"
,
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,
I
I
I
,
,
,
I
.,
.,
,
,
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,
"
.,
,
,
,
,
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WARM SPRINGS
,
,
\
\
\
\
\
,
HelENA
OEER LOOGE
I Smelter Site
t
€
0
z
I 0 10 20
I
Miles
FIGURE 1
ANACONDA SHELTER SITE LOCATION
SOURCE: MODIFIED FROM TETR~ TECH, 1985b.
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FIGURE 2
ANACONDA SMELTER NPL SITE
Anaconda
Superfund
L 0 C a ti.O n s
ActiTilies Lecend
~ bpo4I," ...,.... AriJa OMun1
a bpo4I," ...,.... uu. C-pIria
[IIIJ rornr' PIu&Iq
G;H D/C! 0"U'ft1
1m] D/C! '-pl....
E:jlJtnSeopiac
~ IItn 0"....,
!'22J IOD s:pt4
r;::] c._., OocrM lI.pU.llou
m .....11.110. O'Um,
E::J ....0&11.. c.m,l".
B II. ,.u.
gou..",
Old' orks
Clart Fort GIS
liS - ---......
-;;::=...-.::;- ,.., -- -
---....-....-
/'
_..~:.,
Site
Operable
Unit
Key
m Ldr or ,,"4
r;;:::;I Talll", po"
- Str... ... !rhrtll..
- 1IIr,.,III..1 Slro..
- P,I...., RIti",
- :10<0:1'''' !Jp..,
- 1004 or 3\,"1
./
~~/
r
Mill-Willow
Bypass
fill... r._t.. . ---"" -'
....,,--._.~. ,"""",---.-
~
/
,,",
o
Scale 01 Ililes
[P~90-6J
POOR QUAUT'y
QR\G\NAL
-------
To
Anaconda
...
-f156t3'
(-.'
I@
Tailings
Impoundmenl
radle, Ponds
Q
cJS
@~
Slag Pile
Tailings
Impoundmenl
N
MAP 1
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This Record of Decision (ROD) addresses the Flue Dust as an
"Operable Unit" of the Anaconda Smelter ~ite. Under the National
Contingency Plan (NCP), an operable unit is a "discrete action
that comprises an incremental step toward comprehensively
addressing site problems. This discrete portion of a remedial
response manages migration, or eliminates or mitigates a release,
threat of release, or pathway of exposure." (40 CFR Sect. 300.5).
Subsequent operable units will address other mine and smelting
wastes, surface water, ground water, soils, and other
environmental media.
The centers of population in the vicinity of the Anaconda
Smelter include the communities of Anaconda, Opportunity and Warm
Springs. Approximately 10,500 (84%) of the 12,518 residents of
Deer Lodge County reside within the city limits of Anaconda,
approximately 1.5 miles west of Smelter Hill. The remainder
reside within Warm Springs, Opportunity and surrounding rural
areas.
The land immediately surrounding the present flue dust site
locations has been previously used for mineral processing
operations. This land currently has no specific use but has
recently been classified through the Anaconda-Deer Lodge County
Comprehensive Master Plan as an area that is the least likely to
be developed over the next 30 years due to natural or man-made
limitations, ARCO ownership and the lack of public services.
The region around the site has a complex geologic history
which has resulted in the deposition of sedimentary, igneous, and
metamorphic rocks. A high-angle, north-south trending normal
fault is located approximately 2,000 feet west of the FDS
facility. An inactive geyser is situated close to the junction
of the two fault lines. Quaternary alluvial deposits composed of
sand, gravel, and cobbles have been identified on the eastern
edge of the Smelter Hill site near the former location of Mill
Creek. Perched ground-water zones have been found in the-tuff
bedrock in the vicinity of the Main Flue at depths ranging from
55 to 278 feet below ground surface. Numerous springs, including
hot springs, are present within the Clark Fork Basin.
On Smelter Hill, adjacent to the flue, the native soil is
primarily colluvium consisting of clay, silt, sand, and bedrock
fragments derived from the volcanic deposits. Soils beneath the
eastern portion of the site are rich in calcium carbonate
(travertine). Vegetation in the vicinity of the flue dust site
locations is comprised of rye grasses and small shrubs.
u
Deer Lodge Valley is drained to the north by the Clark Fork
River, which is part of the Columbia River drainage. Warm
Springs Creek and Mill Creek roughly bound the site on the north
and east s~des, respectively, which jOin with discharges from the
Warm Springs Ponds to form the Clark Fork River.
2
-------
The Smelter Hill site lies within the' Warm Springs and Mill
Creek watersheds which are both classified as B-1 streams by the
State of Montana. This classifies the stream as suitable for use
as a source of drinking water, for propagation of salmonoid fish
and associated aquatic life, and other uses. The eastern part of
the site, including the FDS facility (lb), the Miscellaneous
Piles (lc), and the Coal Pile Tracks (la) are located within the
Mill Creek watershed. Runoff from a large portion of the site is
diverted to a number of ditches which flow through, or adjacent
to, the Opportunity tailings ponds and discharge to the Mill-
Willow Bypass. Surface-water runoff from the southeast and
eastern part of the Smelter site flows through a series of man-
made diversions to Mill Creek.
The climate of the site is typical of the western Montana
semi-arid mountain valleys with cold winters, cool summers, and
low precipitation. The annual mean precipitQtion is 13.52
inches. Prevailing wind directions at the top of the Smelter
stack are generally from the south to southwest; however, winds
occasionally blow from the east.
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1
Site History
In 1884, processing of copper ore from mines in Butte
commenced in' the Anaconda, Montana area. Since that time, ore
and concentrates have been processed using a variety of
techniques at the Old Works, Washoe Smelter and the Arbiter.
Plant. The smelting and concentrating operations at the Washoe
Smelter on Smelter Hill began in 1902.
Prior to 1976, flue dust was generated from reverberatory
furnaces and converters and was collected at various stages
between the furnaces and the stack. Small amounts of flue dust
were also collected in flues leading from a zinc roaster.
Initially, the flue dust was reprocessed for arsenic and all
residuals from the Smelter were reprocessed on-site.
In ~976, the ore processing operation was modified with the
installation of an electric arc furnace. Flue dust from the
electric furnace was collected in a baghouse or a Ducon scrubber
which produced pelletized dust and limed scrubber sludges. These
slurried materials were piped to the Bradley Ponds and Iron .Ponds-
where they were stored.
Smelting operations ceased at the site in 1980, and in
September 1983 the Cleveland Wrecking Company began demolition of
structures a~sociated with the concentrating and smelting
operations. The flue dust was removed from the small, subsidiary
flues, baghouses, and precipitators and d~posited at the
3
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T~ickener (2a), Area Cut (2b), Coal Pile Tracks (1a), Switchback
(id), and Miscellaneous Piles (lc). Most of the flue dust in the
Main Flue (5) remained in place.
Construction and placement of flue dust in
('b) commenced in May 1983. Initially, the FDS
designed as a temporary repository for the flue
f=om other on-site locations. The facility was
because of interest in reprocessing of the flue
the FDS facility
facility was
dust material
never completed
dust.
During demolition of the Main Flue, the above-ground walls
of the Main Flue were collapsed into the flue and on top of
remaining dust. Soil and rubble from the adjacent area were
placed on top of the debris. All of the material was covered
¥ith a compacted soil cap and sealed with a soil binder. Berms
~ere constructed to control storm water runoff along both sides
of the Main Flue.
2.2
Response History
The Anaconda Smelter site was placed on the National
Priorities List (NPL) in September 1983, 48 FR 40658 (September
8, 1983). In October 1984, Anaconda Minerals Company (later
~~CO) entered into an agreement with EPA to conduct a Remedial
Investigation at the site under Administrative Order on Consent
Docket No. CERCLA-VII-84-08 (Consent Order 84-08).
Pursuant to Consent Order 84-08, a Work Plan for the
~naconda Smelter Site RI/FS was developed. The Work Plan divided
the study process intc two stages. Stage I included the master
~nvestigation and a number of focused investigations, each with
~ts own RI/FS. Flue dust piles remaining at the site were
designated as one of the several operable units identified for
:ocused investigations. Two Draft Stage I RI reports were
prepared (Flue and FDS Facility Draft Stage I RI reports).
Administrative Order on Consent Docket No. CERCLA-VIII-85-
09 was issued in 1985 to require further investigation and
initiation of control measures to abate the release of fugitive
dust from the Smelter Hill Complex. This Order required ARca to
spray the flue dust piles, excluding the Main Flue, with
surfactant biannually and inspect them daily. In 1987,
~dministrative Order on Consent Docket No. CERCLA-VIII-87-04 was
issued to require investigation of a process to reclaim metals
and treat the flue dust material.
~
A Consent Decree (Civil Action 88-32) was issued in 1988 to
relocate all 37 residents of the Mill Creek community because of
contaminants present in the community and potential sources
remaining on the Smelter site, including flue dust.
~
4
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-
In September 1988, the Flue Dust RIfFS Final Work Plan ~as
prepared pursuant to Administrative Order on Consent Docket No.
CERCLA-VIII-88-'16, which superceded Consent Order 84-08. The
objectives of the Flue Dust RI/FS were: 1) To determine the
nature and extent of the flue dust contamination at the Anaconda
Smelter site and to identify the extent to which a threat, or
potential threat, to human health or the environment exists; and
2) To identify and screen treatment technologies, evaluate
alternatives and select a preferred clean up remedy. Because of
the potential saleable metal content of flue dust, special
emphasis was given to metals recovery technologies. Extensive
bench and pilot scale testing was conducted throughout the RIfFS.
This ROD sets forth the remedy selected for the Flue Dust
Operable Unit of the Anaconda Smelter Site. The primary purpose
of the remedy is to remove, stabilize and contain contaminated
flue dust materials. Subsequent remedial or removal actions
underway or planned at the site will address site contamination
in adjacent soils, surface and ground water.
There are no records of emergency incidents involving fire,
'explosion, death, or injury at the nine flue dust site locations.
However, in June 1986, a heavy rainstorm caused erosion damage to
the Main Flue cap. The collector ditches on each side of the
flue eroded up to 2 feet deep and portions of the original flue
walls were exposed in some areas. No other major incidents at
the flue dust site location have been documented. An EPA-
designated on-site monitor has observed releases of flue dust,
due to wind, from various locations on several occasions.
Monitoring data collected since May 20, 1986 indicates that
no exceedances of lead and TSP air quality Federal and State
standards, or cadmium, zinc, and PM-10 air quality criteria
occurred. However, exceedances of air quality criteria for
copper and arsenic have occurred.
2.3
Enforcement History
The Atlantic Richfield Company (ARCO) has been identified as
the primary potentially responsible party. ARCO merged with the
Anaconda Minerals Company (AMC) in 1977. AMC owned and operated
the smelters from approximately 1884 to 1977. The Cleveland
Wrecking Company was also identified as a PRP for their
involvement with transportation and disposal of wastes during
demolition activities. . .
EPA has issued notice letters to ARCO on several occasions.
ARCO has been actively involved in conducting investigations at
the site since the site was placed on the NPL in September 1983.
EPA, MOHES and ARCO entered into agreement to conduct the Flue
Dust RI/FS-in September 1988 under Administrative Order on
. Consent, Docket No. CERCLA VIII-88-16.
5
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EPA filed suit in 1989 to recover past response costs at the
Smelter site. This case (United States v. Atlantic Richfield
Company, Inc. and Cleveland Wrecking Company, Inc., Docket No. CV
89-39-BU) is currently in litiga~ion.
3.0
HIGHLIGHTS OF COMMUNITY PARTICIPATION
Community involvement in Anaconda Smelter site activities
began early at the site, with the development of the community
relations plan in 1984 and meetings with interested community
groups. The Anaconda Smelter site has drawn much community
interest in the past. Community interest was very intense in
1986-1987 when site contamination required the relocation of the
entire community at Mill Creek (37 residents). Public meetings
and citizen committee gatherings often became highly emotional
encounters between concerned residents and public officials.
Media coverage was extensive including coverage by state and
national newspapers and local and state television stations.
State legislators and Congressional staff members have
recently taken great interest in site activities throughout the
. Clark Fork basin with the focus on expediting cleanups. Their
efforts brought Administrator William Reilly to Anaconda in 1990.
From the beginning of the RIfFS process for the Smelter
site, EPA and MDHES have conducted community relations activities
and sought the involvement of potentially responsible parties
(PRP). These activities have included correspondence with PRPs
and members of the publi~, preparation of press releases and fact
sheets, and periodic meetings with elected officials and the
community to discuss the Superfund process and the status of site
activities. EPA has also contracted an Anaconda community
relations liaison to assist the community with information
requests. The community of Anaconda is also represented on the
Clark Fork Coordinating Forum, an advisory committee for
. superfund activi~ies in the Clark Fork Basin.
During the course of the Flue Dust RIfFS (September 1988 -
June 1991), EPA held several .public meetings and solicited
comments on the RI/FS Work Plan, Sampling and Analysis Plan, data
reports and the risk assessment. EPA and State officials met
regularly with the Anaconda-Deer Lodge Reclamation Advocates as
well as with community public officials.
To further fulfill the requirements of CERCLA Section
113(k)(2)(B)(i-v) and Section 117, the Administrative Record file
was established at EPA's Helena, Montana office. In addition,
important site documents were also kept at the Hearst Free
Library in Anaconda.
~
6
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"
The RI/FS and Proposed Plan were issued on June 3, 1991 wit~
announcements in the Anaconda Leader and Montana Standard.
Copies of the Proposed Plan were also mailed to several hundred
people on the Anaconda mailing list. Because of initial
requests, the RI/FS and Proposed Plan were available for a 60 day
public comment period rather than 30 days. Two public meetings
Nere held in Anaconda at the Copper Village Art Center: 1) an
information meeting, on June 19, 1991, was attended by
approximately 40 people; 2) a public hearing, on July 23, 1991,
was attended by approximately 45 people. A transcript of the
public meeting is included in Administrative Record.
Eleven oral comments were received at the public hearing and
22 written comments were submitted to EPA. The majority of
comments from the local community were in support of the selected
remedy with most wanting an expedient cleanup of the flue dust.
Responses to comments received during the public comment period
are included in the responsiveness summary, which is part of this
Record of Decision.
This decision document presents the selected remedial actic~
for the Flue Dust Operable Unit of the Anaconda Smelter Site,
chosen in accordance with CERCLA, as amended by SARA, and to the
extent practicable, the National Contingency Plan. This decisic~
is based on the administrative record.
4.0
SCOPE AND ROLE OF OPERABLE UNIT
The Anaconda Smelter site consists of the Old Works, Washoe
Smelter, Arbiter Plant, numerous waste piles, waste ponds, and
associated areas contaminated by airborne deposits of smelter
stack emissions. The Anaconda Smelter site covers a wide area.
Because of its size and its complexity, EPA has divided the site
into several smaller operable units. These include the
following:
OU3
OU4
OU7
OU9
OU10
OUll
OU12
OU14
OU15
OU16
Regional Soils .
Regional Surface/Ground
Old Works
Beryllium
Slag
Flue Dust
Arbiter
Smelter Hill
Mill Creek
Community Soils
Water/Tailings
Operable units were prioritized based on their potential
risk to human health and the environment. Mill Creek was
considered the highest priority and a cleanup action was selected
there in 1988. Since flue dust is a principal threat waste and a
source material, the Flue Dust operable unit was considered the
7
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next highest priority. Several removal actions at other operable
units are also underway (OU7, OU9, OU12, OU16) to address other
principal threats at the site, including residential yard
removals. RI/FS studies are also being conducted on several
media-based units at the site (OU7/12 and OU14).
The Flue Dust Operable Unit is located within the boundaries
of the Smelter Hill Operable Unit. It was not the intent of the
Flue Dust RI/FS to address potential risks associated with
adjacent soils, groundwater, or surface water. These will be
addressed under the Smelter Hill Operable Unit RI/FS. The Flue
Dust Operable Unit remedial action, however, will be consistent
with the overall site cleanup objectives.
5.0
SUMMARY OF SITE CHARACTERISTICS
5. 1
Flue Dust Characteristics
Ore processing and smelting at Anaconda have led to
environmental contamination through several routes.
Historically, airborne emissions from the Smelter during
operation, especially from the stack atop Smelter Hill, were a
significant source of contamination. These emissions consisted
of very fine particulate matter containing metallic compounds
(contaminants of concern being arsenic, cadmium and lead). As a
result of their small size, they were distributed widely by the
wind and ultimately deposited on the ground. Since the Smelter
is now closed, it is no longer of concern as a release source.
How~ver, flue dust from prior emissions continues to be a
concern.
Approximately 316,500 cubic yards (approximately 316,500 dry
tons) of flue dust are present at the nine site locations on
Smelter Hill. Flue dust contains high concentrations of metals
such as copper, arsenic, cadmium, lead, and zinc. Flue dust was
generated by smelting operations involving reverberatory
furnaces, electric furnaces, and roasters.. The dust collects in
flues or is removed from the off gases of these processes and
collected by particulate control systems such as baghouses and
electrostatic precipitators.
Flue dust within the Smelter complex can be classified
according to their sources and treatment. Prior to 1976, flue
dust was generated from a reverberatory furnace and was collected
at various stages between the. furnace and the stack. A small. .
amount of flue dust also was collected in flues leading from a
zinc roaster. After 1976, flue dust was generated from an
electric furnace and collected in the baghouse or the Ducon
scrubber. Some of the flue dust from the electric furnace was
piped to settling ponds in a limed slurry or pelletized. The
four gener~l types of flue dust include:
8
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HAP AREA
SITE LOCATION DESIGNATION
Bradley Ponds 7a, 7b
ThJ.ckner 2.
Area Cut 2b
Coal PJ.le Tracks la
S"1tchback Id
Iron Ponds 3a
tscellaneous P11es Ie
FDS FacJ.l1ty Ib
Ha1n Flue
5
TABLE 1
LOCATION AND SOURCE 01 FLUE DUST,
FLUE DUST VOLUME AND TONKAGE ESTIKATEB
SOURCE
Ducon Scrubber/
Electr1c Furnace
Baghou.e/ElectrJc Furnace
Baghouse/ElectrJ.c Furnace
Reverberatory Copper Furnace
"Rev.rber.tory Copper Turn.c.
PrecJp1tators
Baghouse
UnJcno"n-PossJbly trom
Reverberatory Copper Furnace
Th1ckner, 60-toot Flue"and
Cottrells,
HJ.scellaneous PJles ot
Reverberatory Flue Dust
Reverberatory Copper Furnace
Br1ck and Debr1s trom Flue
" DESCRIPTION
L~d scrubber sludge
PelletJz8d dust
Pellet1zed dust
Furnace tlue dust and slag miKture
Turn.c. ~lu. dust .nd sJ.g m~tur.
L1med baghouse dust
DebrJs-metal, glass, rubble
Furnace tlue dust
PelletJzed dust trom baghouse, turnace,
copper reverberatory tlue dust, some
debr J.5
Furnace flue dust, scrap metal, rubble,
5011, br 1ck., masonry
VOWHE
(YD3)
93,534
. 6,491
3,640
39,534
4,067
69,648
5,729
57,221
36,667
316,536
TONNAGE
84,272
6,340
4,383
44,605
4,JI5
65,680
6,802
59,779
40,753
316,929
-------
TABLE 2 SUMMARY OF FLUE DUST CONSTITUENTS: 1989 DATA(a)
.
to,.." "" III 1.11.: n ,- I 1)1111 (h) I\v,', "I~f"
Const I tuent - 2b 7a,7b la ..; 115 -:Ja:Jb 5 Ic III ,--.-
20 COllccl1tralllll1
Arsenic 16,500 13,700 78,1.00 79,200 22,300 58,200 52,800 80,000 42,800 "9,322
Rfsmuth I ,820 1,330 3,220 2 , I 80 1,440 1,250 I ,090 1,200 2,630 1,796
Cadmium 989 1,250 2,940 1,700 1,310 557 176 315 (c) 3,590 I ,564
Cobalt 4/, .0 27.0 71.6 30.4 32.8 57.7 43.0 19.0 22.0 38.6
Copper 244,000 69,400 (d 166,000 157,000 103,000 172 .000 172 ,000 82, 100 1"6,000 155,263
Gold -- (d) 18.9(c) NA(e)
Iron 118,000 77 , I 00 127,000 111,000 175,000 138,000 141 ,000 77 , 400 107 ,000 119,056
Lead 14,40!) 16 , 100 32,300 20,300 21,300 9,260 10,900 10,200 20 , )00 1 7 , 22 IJ
Magnesium 2,640 4,560 3,070 2,110 2,510 .2,040 5,040 1,870 2,340 2,909
Mercury. 27.0 8.3 59.3 218 25.0 86.4 20.5 206(c) 141 7J. 2
Molybdenum 1,150 255 857 715 534 469 250 169 974 597
Nickel 110 29.5 84.9 39.5 36.1 82.3 92.2 33.8 22.7 59.0
Silver 290 106 240 219 154 186 211 122 256 198
Zinc 28,600 20,900 46,000 32,000 29,200 J2 ,000 20,400 19,200 49,000 30,811
(a) All concentrations In m~/kg. AveraRe concentration i8 arithmetic me~n.
(b) Flue du~t Rite numbers defined on FfRure 2-1.
(r) Estlmntrd valu~, Not used In calculation of avera~e concentration.
(el) -- ... undetected.
(e) NA - not appllrnhle.
Source:
Dames & Moore (1989).
~\
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TABLE 3
EPTOX ANALYSES FOR COMPOSITE FLUE DUST SAMPLES
Sile Locarion
Sample 10
AC-COMP
6P.COMP
CTP.COMP
FDS.COMP
IP.COMP
MF.COMP
IAP.COMP
SB.COMP
TH-COMP
"
Alea CUI composite
Bladlev Ponds composlle
Coal pile !lad< composne
Flue dUSI 5101 age composne
lIon Ponds composde
Main nue composite
Miscellaneous plies composne
Switch baCk composlle
Thickenel composite
As
EPio. (j 20.
TABLE 4
COMPARISON OF EP-TOXICITY DATA TO REGULATORY LIMITS(a)
Chromium 5.0
Lead 5.0
Mercury 0.2
Se1 en1um 1.0
SUver 5.0
,.
Conta:i:tant
Arse:1ic
Bariu=
Cadmium
[P Todcitrb)
Limit. m2/L
Site LocatioDs
txceed1n~ L1JII1ts
5.0
Coal Pile Track.
FDS F.cility
Switchback
5.0
1.0
None
Ana Cut
Bradley Pond.
Coal Pil. Track.
FDS Facility
Iron Ponds
Hain Flue
Kiscellaneous Piles
Switchback
Thickener
None
None
Non.
NODe
None
(a) Source: Dames & Hoore 1989.
(b) RCIA rerulat1ons. Part.261.
(c) No exce.d.Dce.
[xceedance
Value. 1:I2/L
22.6
106.0
81.4
--(c)
18.0
22.1
43.7
14.0
24.9
13.8
7.1
2.9
66.4
-------
Wind Erosion Aue Du~ Runoft
Storage Areas
Mua Movement l,c;rd\:18
FAllout , L.8&:ti1Se ~.~.
Air Soil . Ground- Surface
Wind water JOoo. Water
Er1)lion' ~~.t
, Runoff
I" FaJIoLlt <
\. Dermal ,./
Contac: OMking
lncid.ntaI Wit.,
IngHtion Bathin;
Garden
V8Q8t8b181
+ +
Inhalation cf dust Humans Dmkin; Wlt8r
ingestIOn of pattl:l.lL&181 Swimming
FIIh Conaumptbn
FIGURE 3 CONCEPTUAL MODEL OF CONTAMINANT TRANSPORT AND BUMAN- -
. EXPOSURE IN THE VICINI~Y OF THE ANACONDA SMELTER
/
-------
o
o
o
o
Limed sludge from Ducon scrubber
Pelletized dust from the baghouse
Reverberatory furnace flue dust
Limed sludge from the baghouse
These flue dust types and the amounts at each location are
summarized in Table 1 and shown on the map (back cover).
c
Composite samples from each of the flue dust locations were
collected and analyzed by the Contract Laboratory Program (CLP)
for total metals and EP toxicity. Fourteen metals were analyzed
in the flue dust averaging 35% of the sample weight (Table 2).
These data are classified by EPA as enforcement quality. That
is, the data are determined to be valid, defensible, comparable
and of known accuracy and precision. These data are adequate for
use in calculations involving the estimation of risks from
exposure to flue dust.
The major metal constituents are copper and iron, with
lesser amounts of zinc, arsenic, cadmium and lead. Copper was
detected in composite samples with a range of concentration of
6.9 to 24.4 percent, with an average concentration of 14.6
percent. Arsenic concentrations in the composite samples ranged
from 1.4 to 7.9 percent, with an average concentration of 4.9
percent. Cadmium concentrations in the composite samples ranged
from 0~02 to 0.36 percent, with an average concentration of 0.14
percent.
The extraction procedure (EP) toxicity results on the
composite. samples (Table 3) indicated that dissolved metals would
leach from the flue dust mat~rial in quantities greater than
Resource Conservation and Recovery Act (RCRA) regulatory limits
(Table 4). Measured value~ for cadmium exceeded RCRA regulatory
limits at all nine locations and arsenic results exceeded
regulatory limits at three locations. An exceedance of the
regulatory limits is used by EPA to determine if a waste is
hazardous under RCRA. The toxicity characteristic leaching
procedure (TCLP) is presently used to determine compliance with
regulatory limits. TCLP was not used on the flue dust as the EP
was in effect at the time of sampling. However, TCLP was later
used to determine the characteristic of any treated materials.
5.2
Environmental Releases
Under dry and windy conditions, flue dust is subject to..~ihd .
erosion and dispersion, followed by deposition on soil. When
exposed to rainfall or snow melt, the metals in the flue dust can
form a leachate which may adversely affect the quality of
adjacent surface water and groundwater.
Figur~ 3 is a conceptual transport and exposure model
identifying the methods by which contaminants may be released to
9
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the environment, transported between environmental media and
contacted by human receptors. Based on available monitoring
data, air, soil, surface water and- groundwater are all known or
likely to be contaminated to some extent with metals from the
flue dust. Significant pathways of environmental contamination
are summarized by transport medium below.
A background study for the Mill Creek RI/FS attempted to
establish background levels for the contaminants of concern at
the Anaconda Smelter site by evaluating similar areas in the
region. Results of the data (arsenic 15.5 ppm, cadmium 1.4 ppm
and lead 70.4 ppm) indicated that background levels at the site
would be within the range found in most U.S. soils.
Soils with elevated (above background) concentrations of
metals OCcur throughout the southern portion of the Deer Lodge
Valley. Elevated concentrations of metals have been detected in
surface soils more than seven miles northeast of the Smelter.
Soils can. become contaminated from wind erosion and Subsequent
wet and dry deposition of particulate from the air.
Air monitoring data collected near the Anaconda Smelter site
indicate that airborne concentrations of arsenic, lead and
cadmium are also above background concentrations. Of all of the
wastes analyzed at the site, flue dust is the only waste type
with extremely elevated arsenic levels. The elevated
concentrations of. metals in the airborne particulate samples
indicate that flue dust is clearly a source of contaminants due
to air transport occurring near the site. This is further
substantiated by direct visual observations of flue dust
emissions to air during on-site operations.
Small, unnamed tributaries carry surface water runoff in the'
vicinity of the site. A complex system of berms and diversion
channels currently control runoff on-site to the Opportunity
Ponds, and also divert runoff from surrounding areas around the
site. This system is known to have failed under extreme
conditions (e.g. a very strong storm following spring snow melt
causing contaminated runoff to flow into Mill Creek). Except for
these extreme conditions, it is believed that the current runoff
control system and maintenance practices prevent or minimize flue
dust transport by surface water to surrounding streams.
Many other potential release sources are found on the
Smelter site including tailings ponds and slag piles. Data
indicating the nature and distribution in the environment of flue
dust material from the nine flue dust site locations have been
reviewed and assessed. However, it is difficult to dissociate
flue dust and other source distribution associated with past
process operations from the distribution associated with current
flue dust site locations.
.,
1 0
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6.0
SUMMARY OF SITE RISKS
~
During soil sampling of communities near the smelter, it was
discovered that the former community of Mill Creek had extremely
high levels of arsenic (mean avg - 840 ppm) and other heavy metal
contaminants when compared to other communities in the area. A
CentGr for Disease Control (CDC) study showed that pre-school
children from the community of Mill Creek had greater arsenic
exposure than children of other communities in the Anaconda area.
A detailed, quantitative endangerment assessment was
prepared by EPA for the Mill Creek RIfFS, where EPA identified
significant public health risks for children and adults posed by
exposure to arsenic and heavy metals in soil, drinking water,
air, and households in the community of Mill Creek. The
principal waste sources that contributed to contamination in Mill
Creek were the result of Anaconda Smelter operations that have
occurred for nearly 100 years. These sources include historic
stack and fugitive emissions and ongoing fugitive emission from
contaminated areas, including the flue dust locations.
As part of the Flue Dust RIfFS, EPA prepared a Baseline Risk
Assessment in November 1990. .This Risk Assessment was to
characterize, in the absence of remedial action (i.e. the "No
Action" alternative), the current ~nd potential threat to human
health and the environment that may be posed by contaminants
migrating from the flue dust source area. The following sections
. summarize the. findings of the risk assessment.
6.1
Contaminants of Concern
/
Flue dust contains numerous metallic components of potential
health concern. The Risk Assessment focused on those
contaminants that are present in high concentrations and are the
most toxic. In most cases, the relative risk of chemicals at a
site may be evaluated from site monitoring data. In this case,
however, monitoring data on the levels of metals in air and soil
in and around the site do not distinguish between flue dust and
other possible sources of metals (historical deposition from past
Smelter operations, slag piles, natural background levels, etc.).
For this reason, chemical screening was based on the
concentration of each metal in flue dust (Table 5) with a
consideration of the toxic potency of each metal.
Based on this screening the chemicals of primary concern for'
noncarcinogenic effects are arsenic, copper, lead and cadmium.
The chemical of primary carcinogenic concern is arsenic, both by
the oral (soil) and inhalation (air) routes. Cadmium also
contributes a small amount of relative risk via the air route.
Lead may contribute some carcinogenic risk, but the carcinogenic
effects ar~ usually not considered as important as the
noncarcinogenic effects.
1 1
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TABLE 5 SCREENING OF CHEMICALS, 1989 DATA
Soil All'
Toxlel ty Flue IJun Concentration (Cla,n TOXlcltY(b) Risk () Percef5) toxicity RI!lk rerce~5)
Class Component Flue Dust. .g/kg Criterion Factor (R) c Tote I Rank Crlferlon Factor (R) Tot.11 Rank
, Noncancer Arsenic 109,322.0 1.0F.-3 10.9£+7 28 2 __(e) NA ([) 0
CadmlUII 1,564.0 1.0£-] 1.6E+6 1 10 NA 0
Coprer .155,263.0 3.7£-2 10.2£+6 2 J NA 0
Lead 17,729.0 1.4£-4 1~2£+8 69 1 10.]£-10 4.0r." 99 I
Mercury 13.0 3.0£-4 . 2.4£'5 0 5 3.0£-4 2.1,['5 1 2
Nlckd 59.0 2.0£-2 3.0£+] 0 NA 0
Silver 198.0 ].OE-] 6.6£+4 0 NA 0
Zinc 30.811.0 2.0E-I 1.5£+5 ~ NA 0
Total RI8k Factor 1.8£'8 100 Io.OE+1 100
Cancer Arsenic 49.]22.0 1.75£+0 8.6£+10 100 1.5£'1 1.4E'5 99 I
CadrllUil 1,564.0 NA 0 6.1£+0 9.5E'] I 2
Lead 17,229.0 NA 0 NA 0
Nickel 59.0 HA 0 8.4£-1 5.0E+l 0
Total Risk Factor 8.6£.10 100 1.')['5 100
fa) Source: Dames and Hoare 1989.
(b) For noncancer thl8 value 18 the chronic RfD; for cancer thla value la the cancer a I ope
lead are extrapolated frail exillting or prof'Osed regulatlon8 for lead In air and vater.
Ce) The risk fllctor CR) for each clte.lcal 18 calcuillted by the following fOrllullI8Z
factor (SF).
Noncancer toxicity values fnr
1.
For Honeancen
R-.JuXC
2.
For Cancerz
R - SF . C
(d) Thh value" calculated by dlvldln~ each Individual rlRk rector by
(e) -- . Toxicity criterion not ftvalillble for thl8 che.lcal or expoM.re
cheilical has not been eVlllusted.
Cf) NA - Not applicable 81nce no toxicity criterion 18 available.
the 8UII of .11 rlek factora.llnd lIultlplylng by 100.
route, either becau8e. sufficient data are not available, or the
-------
6.2
Exposure Assessment
Two residential populations were selected as those most
likely to be exposed to contaminated media identified in the
previous section. They are the closest current residents located
in East Anaconda and those who may reside on the site some time
in the future. Both child and adult residents were evaluated.
Although access to the site is currently restricted, under
the no-action alternative it is assumed that access becomes
unlimited and that a variety of people might visit the site. It
is also assumed that spraying of the flue dust piles to control
release would not be continued. Those who might visit the site
include site maintenance personnel, hunters, dirt-bike riders,
rock and mineral collectors and tourists. Of these individuals,
dirt-bike riders are assumed to be subject to the highest level
of exposure because wheeled vehicles traversing the storage piles
can raise a large volume of dirt and dust. The suspended
particles may then be inhaled or ingested by the riders.
Based on the distribution of chemicals in the environment
and likely human contact with environmental media, a number of
exposure pathways were identified as being likely or plausible,
including:
o
o
o
o
o
o
Inhalation of particulate matter in air
Ingestion of soils
Ingestion of groundwater
Ingestion of surface water
Dermal contact with soil or surface water
Ingestion of food grown in contaminated soil. .
The intake of contaminants via three routes: 1) Inhalation
of flue dust, 2) Ingestion of soils and dust and 3) Ingestion of
groundwater (for future residents only) were identified as most
likely to result in significant health risks, a~d exposures by
these pathways were selected for quantification.
The contaminant intake equations and values chosen for
various intake parameters were derived from standard exposure
equations and data presented in EPA gUidance documents and site
specific data. Table 6 is a summary of the information,
assumptions and values used for each scenario.
Two types of dose calculations were performed: best
estimate and reasonable maximum. The best estimate dose was
calculated using the geometric mean concentration value of each
chemical in each medium (soil, air, water). The reasonable
maximum dose was calculated using the upper 95th confidence limit
of the geometric mean concentration in each medium.
...
12
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TABLE 6 SUMMARY OF HUMAN EXPOSURE PARAMETERS
Inhalation of Particulates In£estion of Soil In£estion of Water
Body Exposure Exposure Exposure
Popula tion Wt Frequency & Breathing Frequency & Soil Frequency & Water
k Duration Rate Duration Intake Duration Intake
Adult Resident 70 24 hr/d, 1. 3 m3/hr 215 d/yr, 100mg/d 365 d/yr, 2 Lid
215 diy, 30 yr 30 yr
30 yr
Child Resident 16 24 hr/d, 1.0 m3/hr 215 d/yr, 200 mg/d 365 d/yr 1 Lid
215 d/yr, 6 yr 6 yr
6 yr
Dirt Bike Rider 70 3 hr/wk, 2.5 m3/hr 4 events/wk, 50 mg/evcnt - (a) - (a)
13 wk/yr, 13 wk/yr,
30 yr 30 yr
(a) Not evaluated, due to lack of exposure.
~
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Estimation of concentration values is complicated by the
fact that direct measurement (monitoring) of the concentration of
various metallic components of flue dust in environmental media
(air, soil, water) cannot distinguish the levels of contaminants
contributed by flue dust from those contributed by other sources.
For hypothetical future on-site residents, this is of little
concern, since the relative contribution of other sources is
likely to be small in the immediate vicinity of the flue dust
piles themselves. However, for off-site exposures, the relative
contribution of flue dust to total environmental contamination
can only be estimated using mathematical models. Calculations
using available data and simple models indicated that the results
of such modeling efforts were not sufficiently accurate to
justify use. of the values to estimate flue-dust-specific exposure
or risks. For this reason, estimates of exposure of off-site
residents have been performed using only the total level of
contaminants measured in air and soil; these values should not be
confused with estimates of exposure and risk due specifically to
flue dust.
6.3
Toxicity Assessment
Many of the metallic constituents in flue dust can cause
adverse health effects in humans. A brief summary of the effects
of the four metals of chief concern are presented below.
Arsenic. Arsenic is a known human carcinogen, causing lung
cancer when inhaled and skin cancer when ingested. Ingestion of
arsenic may also cause other internal tumors. Arsenic causes a
wide variety of noncancer effects on the skin, blood, nervous
system, liver and kidneys.
Cadmium. Cadmium is a probable
cancer when inhaled. It is not
ingested. Chronic ingestion or
serious injury to the kidneys.
human carcinogen, causing lung
believed to cause cancer when
inhalation of cadmium can lead to
Lead. Lead has been shown to cause liver cancer in rats exposed
to very high doses. However, the noncancer effects of lead are
usually of greater concern. Lead can injure a number of tissues
in the body, but the most sensitive is the nervous system.
Infants and- fetuses are most susceptible to the neurotoxic
effects of lead, since the nervous system is still developing in
these individuals. Lead may also cause increased blood pressure
in adults.
Copper. Copper is a beneficial substance at low doses, and has
relatively low toxicity to humans. The chief effect associated
with ingesting copper is irritation of the gastrointestinal
tract. However, high doses can cause serious effects, including
hemolysis, iiver necrosis, kidney failure, tachycardia, and
convulsions. Copper is not believed to be carcinogenic. Copper
1 3
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Inhalation
Route
Oral
(a)
( b)
( c )
(d)
( e )
can also be quite toxic to aquatic species exposed to runoff or
leachate into surface waters.
The toxic effects of a chemical are quantified by two
parameters: 1) the Reference Dose (RfD), which is a dose below
~hich no noncancer effects are expected to occur, even in
susceptible individuals, and 2) the cancer slope factor (SF),
which is a conservative estimate of the cancer risk per unit
exposure.
,~
The following summarizes the RfD values for the metals of
concern at this site.
Duration
Reference Dose (RfD) (mg/kg-d)(a)
Arsenic Cadmium Copper Lead
Subchronic
Chronic
Subchronic
Chronic
1E-3(b)
1E-3(b)
NA
NA
NA(c)
1E-3(e)
NA
NA
3.7E-2(d)
3.7E-2(d)
NA
NA
NA
NA
NA
NA
Source: USEPA 1990 (HEAST).
This value currently undergoing Agency review.
NA = Not available
Based on current MCL of 1.3 mg/L.
This value is for cadmium in food. This value was chosen
because it is believed to be most applicable to cadmium in
flue dust.
Cancer slope factors for the carcinogenic indicator
chemicals are shown below:
Cancer Weight of
Evidence SF
Route. Chemical Category (mg/kg/day) Reference
Oral Arsenic .A 1 .75 USEPA 1990
Lead B2 NA(a) USEPA 1988c
Inhalation Arsenic A lS(b) USEPA 1988a
Cadmium B1 6. 1 USEPA 1990
( a )
( b)
NA = not available
The SF for inhaled arsenic reported in USEPA (1990) is 50
(mg/kg/daY)-l. This is based on the absorbed dose of
arsenic, which was assumed by the USEPA to be 30% of inh~led
dose. This value has therefore been multiplied by 0.3 to
yield a SF applicable to inhaled (rather than absorbed)
dose.
14
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6.4
Risk Characterization
~
The risk of cancer from exposure to a chemical is calculated
by multiplying the lifetime average daily dose by the appropriate
cancer slope factor (SF). When there is more than one
carcinogenic chemical present, or if exposure to carcinogens
occurs by more than one route, the total cancer risk to an
individual is calculated simply by summing each of the chemical
and route-specific values.
The potential risks of adverse noncarcinogenic effects from
chemical exposures can be expressed in terms of the Hazard
Quotient (HQ). The HQ is the ratio of the estimated dose which a
human receives to the estimated dose level believed to be safe,
the Reference Dose (RfD). This is calculated as follows:
where:
HQ=Hazard Quotient
DI=Daily Intake
RfD=Reference Dose
HQ=DI/RfD
for Chronic Exposure
If the HQ value is less than one (lE+O), it is believed that
there is no significant risk of noncarcinogenic effects. If the
HQ is greater than lE+O, there is risk that noncancer effects may
occur. However, since most RfD values are derived in a
conservative fashion, an HQ value greater that lE+O does not
imply that an adverse effect will necessary Occur.
Although lead can cause serious noncancer effects, there is
no currently agreed upon RfD value. Rather, the noncancer risks
of lead are evaluated by estimating the distribution of
concentrations of ~ead that would Occur in the blood of children
under the exposure conditions assumed. Levels above 10 ug/dl are
considered undesirable.
In the risk characterization, the aggregate carcinogenic
risk due to flue dust contaminants is compared to an acceptable
target risk. The chance of one person in one million people
(10-6) is used as a target value or point of departure above
which carcinogenic risks may be considered unacceptable. This
10-6 point of departure is used when ARARs are not available or
are not sufficiently protective of human health and the
environment.
Using the above mentioned approaches, EPA evaluated the
cancer and noncancer risks associated with the no action
alternative for the Flue Dust Operable Unit in the Final Draft
Baseline Risk Assessment for the Flue Dust Operable Unit. The
results for the reasonable maximum exposure (RME) for arsenic,
cadmium and copper are shown in Table 7. Because of the inherent
uncertainty in these calculations, all results are shown to only
1 5
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TABLE 7
Exposed
Population
Future On-Site
Adult Resident
Future On-Site
Child Resident
Current Off-Site
Adult.Resident
Current Off-Site
Child Resident
Dirt Bike
Rider
",,-
SU;~MARY OF ESTIMATED HUMAN HEALTH RISKS
FLOM ARSENIC, CADMIUM, AND COPPER
Exposure Scenario
Chemical
of Concern
(1) Ingestion
of Soil
Arsenic
Cadmium
Copper
(2) Inhalation
of Dust
Arsenic
Cadmium
Copper
(3) Ingestion
of Yater
Arsenic
Cadmium
Copper
TOTAL FOR FUTURE ON-SITE ADULT
(1) Ingestion
of Soil
Arsenic
Cadmium
Copper
(2) Inhalation
of Dust
Arsenic
Cadmium
Copper
(3) Ingestion
of y'ater
Arsenic
Cadmium
Copper
TOTAL FOR FUTURE ON-SITE CHILD
(1) Ingestion
of Soil
Arsenic
Cadmium
Copper
(2) Inhalation
of Dust
Arsenic
. Cadmium
Copper
TOTAL FOR CURRENT OFF-SITE ADULT
(1) Ingestion
of Soil
Arsenic
Cadmium
Copper
(2) Inhalation
of Dust
Arsenic
Cadmium
Copper
TOTAL FOR CURRENT OFF-SITE CHILD
(1) Ingestion
of Soil
Arsenic
Cadmium
Copper
(2) Inhalation
of Dust
Arsenic
Cadmium
Copper
(a) NA - Not calculated because RfD not available.
TOTAL FOR CURRENT DIRT BIKE RIDER
Excess
Cancer Risk
7xlO-2
7xlO-2
5xlO-4
5xlO-2
2xlO-l
9xlO-;'
3x10-S
2x10-6
1x10-4
9xlO-"
4x10-3
3xlO-s
lxlO-2
Noncancer
Risk (HO)
100
2
5
(;
NA(a)
NA
NA
70
70
3
800
NA
40
NA
NA
NA
200
NA
6
0.1
0.007
0.02
NA
NA
NA
1
NA
0.1
NA
NA
NA
'... ..
"
10
0.2
0.6
NA
NA
NA
-------
one significant figure.
This analysis yields the following main conclusion:
'U
o
An imminent and substantial endangerment would exist
for hypothetical future on-site residents. . Of chief
concern would be a high risk of lung cancer (7 in 100)
resulting from inhalation of arsenic in air, with a
smaller, but still significant risk of lung cancer (5
in 10,000) contributed by cadmium in air. Also, a
concern would be the high risk of skin cancer (7 in
100) due to ingestion of arsenic. Total risk for
cancer is calculated to be 2 in 10. Future on-site
residents (especially children) would also be subject
to high risks of noncarcinogenic effects from arsenic,
cadmium and copper in soil and water.
o
Total lifetime lung cancer risks to current residents
of East Anaconda appear to be on the order of 3 in
100,000. This is due mainly to arsenic in air, with
lower risk levels due to cadmium in the air. Skin
cancer risks from ingestion of arsenic in soil are
probably around 9 in 100,000. As noted earlier, these
are total risks, and the fraction of this risk that is
due specifically to flue dust is not known.
o
Occasional visitors to the site (dirt-bike riders)
could have a substantial cancer risk (up to a risk of 9
out of 1,000 for skin ~ancei and 4 out of 1,000 for
lung cancer) if site visits involved significant
contact with flue dust and site visits occurred over a
long period. In addition, significant risks of
noncancer effects could also occur, due mainly to the
presence of arsenic in flue dust.
As noted above, the effects of lead are evaluated by
calculating the expected distribution of blood lead values. For
the future on-site residential child, the average blood lead
would be 73 ug/dL, far above acceptable levels (10 ug/dL). For
current off-site children, the estimated average blood lead value
is 2.6 ug/dL, within the acceptable range.
Thus, the flue dust piles currently on site pose a
significant health risk to hypothetical future residents of the
site and may also be contributing to health risks of site
visitors or nearby residents. Actual or threatened releases of
hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may
present an imminent and substantial endangerment to public
health, welfare, or, the environment.
/
16
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6.S
Environmental Risks
Flue dust can also lead to environmental contamination in a
variety of ways. One important pathway is wind erosion of the
flue dust, followed by dispersion of these particles in air to
surrounding areas. The flue dust then settles, leading to a
gradual accumulation in the soil. Flue dust may also contaminate
the environment through leaching of the contamination to surface
waters (ponds, creeks, etc.) or into the groundwater beneath the
piles.
Risks to plant and animal species on and around the site
cannot be evaluated quantitatively with current data, but
analysis of information of species likely to be present and
pathways of flue dust migration suggest the following:
7.0
o
Aquatic species in Warm Springs Creek or Mill Creek are
not likely to be affected by flue dust under current
conditions, since runoff from the site is controlled
and does not reach these waters. Under the no-action
alternative, however, current control systems would be
expected to fail and runoff would likely lead to
significant exposure of organisms in the creeks.
o
Flue dust contamination of soil, both on site and off
site (primarily in the downwind direction) can lead to
contaminant uptake by vegetation and crops. This could
be further increased by.direct deposition (wet or dry)
of flue. dust on foliar surfaces.
o
Herbivorous wildlife could be exposed by consumption of
contaminated plant material or soil, as well as by
direct inhalation of flue dust in air. Although the
magnitude of the risks posed to ecological species by
flue dust cannot be estimated with current data, these
risks are of concern.
DESCRIPTION OF ALTERNATIVES
A feasibility study was conducted to develop and evaluate
alternatives for the Flue Dust Operable Unit. Remedial
alternatives were assembled from applicable remedial technology
process options and were initially evaluated for effectiveness,
implementability, and cost. The alternatives meeting these .-- .
criteria were then evaluated and compared to nine criteria
required by the NCP. In addition to the remedial alternatives,
the NCP requires that a no-action alternative be considered at
every site. The no-action alternative serves primarily as a
point of comparison. for other alternatives.
~
17
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The feasibility study evaluated six alternatives for
addressing human health and environmental problems caused by the
flue dust material. Each of the six alternatives is summarized
in the following sections and on Table 8. .
7. 1
ALTERNATIVE 1:
NO ACTION
D
The NCP requires that the "No Action" alternative be
evaluated at every site to establish a baseline for comparison.
Under this alternative, EPA would take no further action at the
site to prevent exposure to flue dust, including the current
biannual surfactant applications.
Because this alternative would result in contaminants
remaining on-site, CERCLA requires that the site be reviewed
every five years. If indicated by the review, remedial actions
would be implemented at that time to remove or treat the wastes.'
Since no action-would take place, there would be no capital or.
operation and maintenance costs.
7.2
ALTERNATIVE 2: DISPOSAL OF UNTREATED FLUE DUST IN AN
ONSITE REPOSITORY
Under this alternative, all 316,500 cubic yards of flue dust
and debris from the nine pile locations would be excavated,
hauled, and directly placed into a repository meeting applicable
or relevant .and appropriate Montana Hazardous Waste Act and
Resource Conservation and Recovery Act (RCRA) Subtitle C
statutory and re9ulatory disposal site requirements.
Flue dust is a mineral processing waste that is a
characteristic hazardous waste and that was disposed of after
1980. Recently, materials such as flue dust were removed from
the Bevill exclusion (newly identified waste) making RCRA
Subtitle C an applicable requirement. Although this alternative
would involve the excavation and placement of a hazardous waste,
regulated under RCRA, the RCRA Land Disposal Restrictions (LDRs)
are not applicable requirements as newly identified wastes do not
have treatment standards under the land disposal restrictions.
This alternative includes the removal of all flue dust
located on Smelter Hill (316,500 cubic yards), including flue
dust in the Main Flue. This includes the removal of adjacent
soils that contain visually distinct flue dust in concentrations
greater than concentrations of contaminants in surrounding s6i1s.
Confirmation sampling of arsenic and cadmium would be required to
ensure adequate removal. Cleanup of remaining soils will be
evaluated under the Smelter Hill Operable Unit. Some RCRA
closure requirements contained in 40 CFR S 264.258 as
incorporated into ARM S 16.44.702 would be relevant and
appropriate to stabilize the site. Final closure of the nine
flue dust locations is not within the scope of this project but
18
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TABLE 8
SUMMARY OF ALTERNATIVES
~~
COMPONENTS
ALTERNATIVES *
2 3 4 5 6
Removal
0 Complete x x x x x
o Partial
Treatment
0 Cement/silicate x ? x
Stabilization
0 Metals Removal x x
o Chemical Fixation x
Disposal
0 Offsite (TSD) x
0 Onsite (RCRA Subtitle C) x
0 Onsite (Engineered Repository) x x x
Institutional Controls
0 Groundwater Monitoring x x x x
o Site Access Restriction x
ALTERNATIVES *
1 .
2.
3.
4.
No Action
Disposal of untreated flue dust in and onsite repository.
Offsite disposal of untreated flue dust.
Onsite stabilization/fixation, disposal in and
engineerepository.
Onsite metal removal/chemical fixation, disposal in an
engineered onsite repository.
Onsite metal removal, stabilization, disposal in an
engineered onsite repository.
,
s.
6.
- -
"
",.-
-------
rather to be determined under the Smelter Hill Operable Unit.
CJ
Flue dust would be excavated and transported to the
repository using conventional earthmoving equipment such as
loaders, dozers and off road haul trucks. Because of the
potential for release during excavation and transport, dust
suppression and air monitoring would be required.
The repository would be designed and constructed in
accordance with the requirements specified in ARM S 16.44.702 as
it incorporates 40 CFR S 264.301, including among other things, a
double liner system, leachate control, impermeable cap and
monitoring. The liner system would be designed and constructed
to prevent the migration of contaminants out of the repository
into underlying soils or groundwater and would include a leachate
collection and removal system. The cap would be designed and
constructed to promote drainage, minimize erosion of the cover,
and provide long-term minimization of migration of liquids
through the underlying contaminated soils. Consistent with the
requirements of ARM S 16.44.702 as it incorporates 40 CFR S
264.117, long-term operation and maintenance would be conducted
to monitor the groundwater around the repository and to ensure
the integrity of the cap.
The repository would be protected with institutional
controls which include site access and land use restrictions.
Successful excavation and placement of the flue dust in a
repository meeting applicable or relevant and appropriate RCRA
Subtitle C requirements would be expected to reduce contamination
levels at the flue dust locations to concentrations equivalent to
surrounding soils and effectively reduce the risk of flue dust
contaminant release from the repository. The estimated capital
cost of this alternative is $7,482,000, with annual O&M costs
estimated to be $10,000. The estimated time to implement this
remedy and meet the cleanup requirements is approximately two
years.
7.3
ALTERNATIVE 3:
OFFSITE DISPOSAL OF UNTREATED FLUE DUST
Under this alternative, flue dust from the nine pile
locations would be excavated and transported to an offsite RCRA
Transfer, Storage and Disposal (TSD) facility. Requirements
under RCRA would govern shipping and manifesting the material to
the TSD facility.
/
This alternative includes the removal of all flue dust
located on Smelter Hill (316,500 cubic yards), including flue
dust in the Main Flue. This includes the removal of adjacent
s01ls that contain visually distinct flue dust 1n concentrations
greater than concentrations of contaminants is surrounding soils.
Confirmation sampling of arsenic and cadmium would be required to
ensure adequate removal. Cleanup of remaining soils will be
19
-------
evaluated under the Smelter Hill Operable Unit. Some RCRA
closure requirements 40 CFR 9 264.258 as incorporated into ARM S
16.44.702 would be relevant and appropriate to stabilize the
site. Final closure of the nine flue dust locations is not
within the scope of this project but rather to be determined
under the Smelter Hill Operable Unit.
~ )
Flue dust would be excavated and transported to a transfer
station using conventional earthmoving equipment such as loaders,
dozers and off road haul trucks. The flue dust would be
transferred from haul trucks through a mobile hopper for
conveyance to railroad container cars at the site. Because of
the potential for release during excavation and transfer, dust
suppression and air monitoring would be required. Rail transport
would occur on existing lines at the site.
The flue dust would then be transported to a permitted out-
of-state disposal facility. Requirements under the. Montana
Hazardous Waste Act, RCRA and Department of Transportation
regulations would govern shipping and manifesting the material to
the disposal facility. Maintenance and monitoring of the
disposed ~aterial would be the responsibility of the facility
operator.
Successful excavation and transport of flue dust to a
permitted RCRA TSD facility would be expected to reduce
contamination levels at the flue dust locations to equivalent
concentrations in surrounding soils and effectively reduce the
risk of flue dust contaminant release from the TSD facility. The
estimLtedcapital cost of this alternative is $71,933,000, with
no annual O&M costs. The estimated time to implement this remedy
and meet the cleanup requirements is 'approximately one year.
7.4
ALTERNATIVE 4: ONSITE STABILIZATION, DISPOSAL IN AN
ONSITE ENGINEERED REPOSITORY
This alternative is the selected remedy and was identified
as the preferred remedy in the Proposed Plan. The major
components of this alternative include the excavation of flue
dust at each of the nine flue dust locations, onsite
stabilization using a cement/Silicate based process, and disposal
of treated residues in an onsite engineered repository.
This alternative includes the removal of all flue dust
located on Smelter Hill (316,500 cubic yards), including flue' .
dust in the Main Flue. This includes the removal of adjacent
soils that contain visually distinct flue dust in concentrations
greater than concentrations of contaminants in surrounding soils.
Confirmation sampling of arsenic and cadmium will be required to
ensure adequate removal. Cleanup of remaining soils will be
evaluated under the Smelter Hill Operable Unit. Some RCRA
closure requirements 40 CFR 9 264.258 as incorporated into ARM 9
20
-------
16.44.702 will be relevant and appropriate to stabilize the
Final closure of the nine flue dust locations is not within
scope of this project but rather to be determined under the
Smelter Hill Operable Unit.
site.
the
u
The flue dust will be treated at each of the nine flue dust
locations with a mobile crusher and cement batch plant. The flue
dust will be stabilized to meet RCRA TCLP regulatory limits. The
flue dust will be treated in accordance with 40 CFR Subpart X, as
incorporated into ARM S 16.44.702, for standards for a treatment
unit. The specific process will be determined in the Remedial
Design Phase ~hough engineering design and analysis.
The processed material will then be transported to an onsite
repository for disposal using standard cement trucks. Dust
suppression and air monitoring will be required. No transport on
public roads will be allowed.
Treatability testing indicated that the mobility of
contaminants of concern (arsenic, cadmium and lead) can be
effe~tively reduced (62% to 99%) to meet the BOAT or TCLP RCRA
regulatory limits. Additional leaching tests (MEP, ANS 16.1)
also indicated that the material will meet the regulatory limits
over the long term (see attachment 2).
Because it is expected that treatment of the flue dust
material will remove the hazardous characteristic from the
material, this alternative will not involve the disposal of a
RCRA regulated waste, and RCRA Subtitle C requirements are not
applicable. However, some RCRA Subtitle C requirements have been
determined to be relevant and appropriate to the type of
substances being managed. The repository will be designed and
constructed in accordance with the requirements specified in the
Montana Solid Waste Management Act, RCRA Subtitle 0, and selected
RCRA Subtitle C requirements and will include among other things,
a liner system, leachate control, impermeable cap and monitoring.
The liner system will be designed and constructed to prevent the
migration of contaminants out of the repository into underlying
soils or groundwater and will include a leachate collection and
removal system. The cap will be designed and constructed to
promote drainage, minimize erosion of the cover, and provide
long-term minimization of migration of liquids through the
underlying contaminated soils. Consistent with the requirements
of 40 CFR Section 264.117, as incorporated into ARM Section
16.44.702, long-term operation and maintenance will be conducted
to monitor the groundwater around the repository and to ensure
the integrity of the cap.
21
-------
The re~ository will be protected with institutional controls
which include site access and land use restrictions. Successful
excavation, treatment and placement of the treated flue dust
material in an onsite engineered repository will be expected to
reduce contamination levels at the flue dust locations to
equivalent ccncen~rations in surrounding soils and effectively
reduce the risk of flue dust contaminant release from the
repository. The estimated capital cost of this alternative is
$25,338,000, with annual O&M costs estimated to be $10,000. The
estimated time to implement this remedy and meet the cleanup
requirements is approximately three years.
7.5
ALTERNATIVE 5: ONSITE METAL REMOVAL/CHEMICAL FIXATION,
WITH OR WITHOUT ADDITIONAL STABILIZATION, DISPOSAL IN
AN ENGINEERED ONSITE REPOSITORY
The major components of this alternative include the
excavation of flue dust at each of the nine flue dust locations,
onsite hydrometallurgical treatment and disposal of the treated
material in an onsite engineered repository.
This alternative includes the removal of all flue dust
located on Smelter Hill (316,500 cubic yards), including flue
dust in the Main Flue. This includes the removal of adjacent
soils that contain visually distinct flue dust in concentrations
greater than concentration of contaminants in surrounding soils.
Confirmation sampling of arsenic and cadmium would be required to
ensure adequate removal. Cleanup of remaining soils will be
evaluated under the Smelter Hill Operable Unit. . Some RCRA
closure requirements 40 CFR S 264.258 and ARM S 16.44.702 would
be relevant and appropriate to stabilize the site. Final closure
of the nine flue dust locations is not within the scope of this
project but rather to be determined under the Smelter Hill
Operable Unit. .
Flue dust would be transferred from the nine flue dust
locations to a central location for treatment using a chloride
leaching technology which would remove saleable metals and
produce a long-term stable residue material which would not leach
contaminants above RCRA TCLP regulatory limits. The flue dust.
would be treated in accordance with 40 CFR Subpart X, as
incorporated into ARM Section 16.44.702, standards for a
treatment unit. The specific process would be determined in th~
Remedial Design Phase though engineering design and analysis.
The processed material would then be transported to an onsite
repository for disposal. Because of the potential for release of
contaminants during excavation, transfer and treatment, dust
suppression and air monitoring would be required.
22
-------
~
The chloride leaching technology was represented by the
innovative Cashman Process. Initial bench-scale test results
indicated that saleable metals could be removed while producing a
stable residue product. Additional test results collected during
the pilot-scale testing indicated that the residue would fail
TCLP limits for lead (see Attachment 2). Although it is believed
that the process could be adjusted to produce the desired
residue, testing also indicated that the technology would be very
complex and would be difficult to operate and produce a
consistently stable residue. If a desired residue could not be
produced, additional stabilization of the material would be
required to meet RCRA regulatory limits. Marketable products
would be sold to various metallurgical processing facilities for
subsequent metal recovery.
Because treatment of the flue dust material (possibly with
aqditional stabilization) would remove the hazardous
characteristic from the material, this alternative would not
involve the disposal of a RCRA regulated waste, and RCRA Subtitle
C requirements are not applicable. However, some RCRA Subtitle C
requirements have been determined to be relevant and appropriate
to the type of substances being managed. The repository would be
designed and constructed in accordance with the requirements
specified in the Montana Solid Waste Management Act, RCRA
Subtitle D and selected RCRA Subtitle C requirements and will
include among other things, a liner system, leachate control,
impermeable cap and monitoring. The liner system would be
designed and constructed to prevent the migration of contaminants
out of the repository into underlying soils or groundwater and
would include a leachate collection and removal system. The cap
would be designed and constructed to promote drainage, minimize
erosion of the cover, and provide long-term minimization of
migration of liquids through the underlying contaminated soils.
Consistent with the requirements of 40 CFR S 264.117, as
incorporated into ARM S 16.44.702, long-term operation and
maintenance would be conducted to monitor the groundwater around
the repository and to ensure the integrity of the cap.
The repository would be protected with institutional
controls which include site acce~s and land use restrictions.
Successful excavation, treatment and placement of the treated
flue dust material in an onsite engineered repository would be
expected to reduce contamination levels at the nine flue dust
locations to concentrations equivalent in surrounding soils and
effectively reduce the risk of flue dust contaminant release "from
the repository. The estimated capital cost of this alternative
is $47,854,000, with annual O&M costs estimated to be $14,487,000
during the treatment operation and $10,000 thereafter.
Recoverable revenue is estimated to be $12,000,000 during the
treatment operation. The estimated time to implement this remedy
and meet tfte cleanup requirements is approximately seven to ten
years.
23
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7.6
ALTERNATIVE 6: ONSITE METAL REMOVAL, STABILIZATION,
DISPOSAL IN AN ENGINEERED ONSITE REPOSITORY
The major components of this alternative include the
excavation of flue dust at each of the nine flue dust locations,
onsite metals removal, stabilization of treated residues and
disposal of the treated material in an on site engineered
repository.
This alternative includes the removal of all flue dust
located on Smelter Hill (316,500 cubic yards), including flue
dust in the Main Flue. This includes the removal of adjacent
soils that contain visually distinct flue dust in concentrations
greater than concentrations of contaminants in surrounding soils.
Confirmation sampling of arsenic and cadmium would be required to
ensure adequate removal. Cleanup of remaining soils will be
evaluated under the Smelter Hill Operable Unit. Some RCRA
clo.sure requirements 40 CFR ~ 264.258 and ARM ~ 16.44.702 would
be relevant and appropriate to stabilize the site. Final closure
of the nine flue dust locations is not within the scope of this
project but rather to be determined under the Smelter Hill
Operable Unit.
The flue dust materials would be transported from the nine
flue dust locations to a central location for treatment using a
sulfuric acid leaching technology to remove saleable metals.
Based on treat~bility testing, leach residues are not expected to
meet TCLP regulatory limits. Residues not meeting the TCLP
limits would be stabilized by a cement/silicate-based
stabilization process as described in Alternative 4. Testing of
stabilized treated residues indicated that the material would
meet TCLP regulatory limits and be stable over the long term (se
Attachment 2). Marketable products would be sold to various
metallurgical processing facilities for subsequent metal
recovery.
The flue dust would be treated in accordance with 40 CFR
Subpart X, as incorporated into ARM ~ 16.44.702, standards for a
treatment unit. The specific process would be determined in the
Remedial Design Phase though engineering design and analysis.
The processed material would then be transported to an onsite
repository for disposal. Because of potential releases during
excavation, transport and treatment, dust suppression and air
monitoring would be required.
Because treatment of the flue dust material (with additional
stabilization) would be expected to remove the hazardous
characteristic from the material, this alternative would not
involve the disposal of a RCRA regulated waste, and RCRA Subtitle
C requirements would not be applicable. However, RCRA Subtitle C
requirements have been determined to be relevant and appropriate
to the type of substances being managed. The repository would be
24
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TABLE 9
CLEANUP EVALUATION CRITERIA
Overall Protection or Human Health and the Environment addresses whether or not a remedy provides ade-
quate protection and evaluates how risks posed lhrough each pathway are eliminated, reduced, or controlled.
Compliance with Applicable or Relevant and Appropriate RequIrements (ARARs) addresses whether or not a
r~dmedy willds~cct all a,Pplicable or re~~~~~ andappropriate.~ederal and State ~viro~CDtallaws and\or pro-
VI e groun lor a waIver.' '.
Short-Term Effectiveness addresses the period of time needed to complete the remedy, and any risks to human
health and the environment that may be posed during the construction ~d implementation of the remedy.
. .
Long-Term Etrectfveness and Permanence refers to the ability of a remedy to provide reliable protection of
human health and the environment over time.
Reduction or Toxicity, Mobility, or Volume Through Treatment refers to the preference for a remedy that re-
duces health hazards, movement, or quantity of contaminants at the site. .
Implemental:!ility refers to the technical and administrative feasibility of a' remedy. This includes the availability
of materials and services needed to carry out a remedy. It also includes coordination of Federal, State, and locaf
governments to work together to cleanup the site.
Cost-Effectiveness evaluates the estimated capital and operation and maintenance costs of each alternative in
comparison to other equally protective alternatives.
State Acceptance indicates whether the State agrees with, opposes, or has no comment On the preferred alterna-
tive. . .
Community Acceptance includes deteimining which parts of the alternatives interested persons in the commu-
nity support, have reservations about, or oppose.
,
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~
TABLE 10
COMPARATIVE ANALYSIS OF ALTERNATIVES
AL'l'&lU8ATlva .
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the 8.""1I'0...nt.. U'II'OU9h ,Iac...nt 0' t.hrouvh plaC-IIt. 0' t.hC'ou,... prodvctlon 0'
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.1.~nt ..- ..
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v
designed and constructed in accordance with the requirements
specified in the Montana Solid Waste Management Act, RCRA
Subtitle 0 and selected RCRA Subtitle C requirements and will
include among other things, a liner system, leachate control,
impermeable cap and monitoring. The liner system would be
designed and constructed to prevent the migration of contaminants
out of the repository into underlying soils or groundwater and
would include a leachate collection and removal system. The cap
would be designed and constructed to promote drainage, minimize
erosion of the cover, and provide long-term minimization of
migration of liquids through the underlying contaminated soils.
Consistent with the requirements of 40 CFR 9 264.117, as
incorporated into ARM 9 16.44.702, long-term operation and
maintenance would be conducted to monitor the groundwater around
the repository and to ensure the integrity of the cap.
The repository would be protected with institutional
controls which include site access and land use restrictions.
Successful excavation, treatment and placement of the treated
flue dust material in an onsite engineered repository would be
expected to reduce contamination levels at the nine flue dust
locations to concentrations equivalent in surrounding soils and
effectively reduce the risk of flue dust contaminant release from
the repository. The estimated capital cost of this alternative
is $14,720,000, with annual O&M costs estimated to be $8,033,000
during the operation and $10,000 thereafter. The estimated
recoverable revenue is $7,152,000 during the operation. The
estimated time to implement this remedy and meet the cleanup
requirements is approximately seven to ten years.
8.0
EVALUATION OF ALTERNATIVES
In accordance with the NCP, 40 CFR Section 300.430(e), the
remedial alternatives developed in the FS were. analyzed in detail
using the nine evaluation criteria (Table 9). These criteria
are: 1) overall protection of human health and the environment;
2) compliance with applicable or relevant and appropriate
requirements (ARARs); 3) reduction of toxicity, mobility, or
volume through treatment; 4) long-term effectiveness and
permanence; 5) short-term effectiveness; 6) implementability; 7)
cost; 8) state acceptance; and 9) community acceptance. Each of
the alternatives were evaluated against the nine criteria (Table
10) and against the other alternatives as discussed below.
8.1
Overall Protection
All of the alternatives, with the exception of the "no
action" alternative, would provide adequate protection of human
health and the environment by eliminating, reducing, or
controlling~risk through treatment, engineering controls, or
institutional controls. Alternative 4 would immobilize hazardous
25
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constituents, through treatment, and contain the treated
materials in an engineered repository to reduce risks associated
with direct contact effectively reducing the release of
contaminants to the environment. Alternative 4 would appear to
provide the greatest overall protection through the containment
of an effective long-term material, using a demonstrated
technology, in a timely manner.
Alternative 6 would also provide similar overall protection,
to Alternative 4, by immobilizing hazardous constituents through
metals removal and stabilization under Alternative 4. The
removal of saleable metals, primarily copper, would not
significantly improve the overall protection as the contaminants
of most concern (arsenic, cadmium and lead) would remain in the
treated material.
Alternative 5 would also provide similar p~otection to
Alternative 4, with the removal of copper, zinc, cadmium and
lead, but with arsenic remaining in the treated material.
Alternative 6 would immobilize arsenic, similar to Alternative 4,
through metals removal and stabilization. Although uncertain at
this time, immobilization could be achieved without additional
stabilization. In both Alternatives 5 & 6, overall protection
would take longer to achieve and with a significantly greater
chance of uncertainty for success.
Because the "no action" alternative is not protective of
human health and the environment, it is not considered further in
this analysis as an option for this operable unit.
8.2
Compliance With ARARs
All alternatives would be designed and implemented to attain
all their respective applicable or relevant and appropriate
requirements (ARARs) of Federal and State environmental laws. No
waiver from ARARs is necessary to implement Alternatives 2
through 6. .
8.3
Long-Term Effectiveness and Permanence
Alternative 4 would provide for a high degree of long-term
effectiveness and permanence by immobilizing the hazardous
constituents, through stabilization, using a demonstrated
technology. Containment of the stabilized material in an ".
engineered repository would provide for additional long-term
security. Long-term effectiveness and permanence would be
dependent on the long-term stability of the stabilized material
and the long-term integrity, maintenance, and monitoring of the
engineered repository.
~
26
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o
Treatability testing indicated that the stabilized material
~ould immobilize arsenic, cadmium and lead to meet regulatory
limits (TCLP leach tests) and provide for long-term stability as
determined from the Multiple Extraction Procedure (MEP) and leach
tests used by the American Nuclear Society (see Attachment 2).
Alternative 6 would also provide similar long-term effectiveness
and permanence to Alternative 4 through the additional
stabilization "of materials.
~
. Alternative 5 would provide additional long-term
effectiveness and permanence through the removal of cadmium and
lead. However, testing (lead values) has indicateQ that the
treated material would require additional stabilization. Arsenic
values, however, would appear to be lower over the long-term. As
stated above, there is a much higher degree of uncertainty for
success associated with both the metal removal alternatives.
Alternative 2 would provide for containment of flue dust,
but since there is no treatment, the potential for release
exists, if there were a failure of the monitoring or containment
system. Alternative 3 would provide long-term effectiveness and
permanence through the removal of flue dust offsite. However,
since there is no treatment, the same potential for release would
exist at the out-of-state facility.
8.4
Reduction of Toxicity, Mobility, or Volume of
Contaminants Through Treatment
Only alternatives 4 through 6 would treat the flue dust
material. Alternative 4 would reduce the mobility of
contaminants in the flue dust material. Arsenic leachate would
be reduced by 62-99 percent, cadmium by 99 percent and lead 90-99
percent. Volume would be increased by approximately 15 percent.
"Alternative 6 would remove some saleable metals, mainly
copper, reduce arsenic, cadmium and lead leachate mobility
through treatment, similar to Alternative 4, and increase the
total volume for disposal by approximately 16 percent. Although
this alternative removes copper, it does not reduce the toxicity
of flue dust with respect to the primary elements of concern
(i.e. arsenic, cadmium and lead).
Alternative 5, would remove additional saleable metals
including cadmium and lead, but would not remove arsenic. If the
hydrometallurgical treatment alone was successful in produci~g" a
stable residue material, volume increase would only be
approximately four percent. If additional stabilization is
necessary to reduce the mobility of flue dust contaminants,
volume would ~ncrease by approximately 13 percent.
27
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8.5
Short-Term Effectiveness
Alternatives 2 through 6 each involve flue dust excavation
and transportation. Similar dust control activities would be
implemented under each of these alternatives. Alternative 4
provides the greatest short-term effectiveness by having the
least number of untreated flue dust handling and transportation
steps. Under Alternative 4, a mobile crusher and batch plant
would be set up at each of the flue dust piles reducing the
chance of contaminant release through transporting of flue dust.
The treated material would then be transported to the repository.
Alternative 4 would be completed in three years.
Alternatives 5 and 6 would require additional dust control
during transportation of flue dust to a central process area
where blending of flue dust would be needed to prepare a
feedstock. Completion of both alternatives would take seven to
ten years and could have other short-term risks related to
process activities which could impact the workers and the
environment, including the production of additional waste
streams.
Alternative 2 would require additional dust control during
transport and placement into an onsite repository and take
approximately two years. Alternative 3 would require additional
dust control during flue dust on-loading and off-loading from the
railroad container cars and take approximately one year.
However, untreated flue dust would be stockpiled at the out-of-
state facility another two to three years before disposal.
8.6
Implementability
Alternative 2 is easiest to implement. Excavation and
transport of flue dust could be accomplished with conventional
equipment. Dust control could also be obtained with standard
technology. Implementability concerns a~e anticipated to be
minimal for the repository associated with alternatives 2, 4, 5
and 6. .
Alternative 4 would be implemented with a demonstrated
stabilization technology, using standard equipment and would be
easily accomplished. Alternative 3 would use standard, proven
technologies for excavation and transportation. However, moving
large volumes of waste over long distances could cause some
additional concerns.
Alternative 5 would require construction of a relatively
complex processing facility using exceptionally expensive
construction materials. Replacement parts and backup equipment
would be more difficult to obtain. Alternative 6 would also
require tne construction of a complex hydrometa1lurgical
facility. Technologies in Alternatives 5 and 6 have not been
28
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p~=~en at a full scale operation and would require additional
d:sign and testing. Uncertainties with implementability are
c:~sidered high.
8.7
Cost
~
The following cost figures were estimated for purposes of
cc~paring the various alternatives in the RI/FS, and were based
o~ limited site specific information. The costs are presented as
p=esent worth, which is the total cost of the remedy over time,
i~~luding operation and maintenance, in present day dollars. The
lc~est cost alternative would be Alternative 2 at $6,911,000.
T~e highest cost alternative would be Alternative 3 at
$~1 ,933,000. The present worth cost for Alternative 6 would be
$.9,189,569. The present worth cost of Alternative 4 would be
$:1,866,000. The present worth cost for Alternative 5 would be
$:0,200,000 wrth additional stabilization and $40,100,000 without
a=ditional stabilization. Table 11 compares the costs of the
a:ternatives.
.
A sensitivity analysis of the net present value costs of
A:ternatives 4 through 6 was performed. The economic variables
e~aluated were those with significant economic impact (i.e
c:nstruction costs, operation and maintenance costs and price of
c~pper). Based on a "best case" "worst case" analysis, both
~:ternatives 5 and 6 had a high degree of cost variability, while
~:ternative 4 had the least variation. Costs ranged from $19.1
~:llion to $24.9 million for Alternative 4, $27.8 million to
$38.4 million for Alternative 5 with the additional stabilization
(518.7 million to $78.4 million without stabilization); and $6.5
~:llion to $34.7 million for Alternative 6.
8.8
State Acceptance
MDHES has provided input to EPA during the RI/FS process.
Eased upon information that was available, MDHES concurred with
E?A's selection of Alternative 4 as the Preferred Alternative in
t~e Proposed Plan.. MDHES's concurrence in the selection of
~lternative 4 was based upon the understanding that all
~egulatory requirements would be met, including the applicable or
~elevant and appropriate Montana Hazardous Waste Act and RCRA
S~btitle C repository design requirements. It is anticipated
~~at the State of Montana will also concur with the selected
~emedy in this ROD.
8.9
Community Acceptance
Based upon public comment, the majority of the community
supports EPA's selection of Alternative 4 as the remedy. The
~esponsiveness summary is included in this ROD.
~
29
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<
Item Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5A Alternative 58 Alternative 6
No Action Onsite Offsite Stabilization Cashman Cashman Ambient
Disposal Disposal Fixation Process Process Leach
Initial Cost 0 3,741,000 11,933,000 8,446,000 41,854,000 41,854,000 1,360,000
O&M 0 10,000 None 10,0002 11,546,000. 14,481,000. 8,033,000.
10,000' 10,000' 4,217,0006
10,0006
Future 0 3,741,000' None 8,446,000' 7,360,000'
Cost
Saleable 0 0 0 0 12,000,000. 12,000,000. 7,152,000.
Products
Total 0 6,911,000 11,933,000 21,866,000 40,100,000 50,200,000 19,189,569
Present
Worth
1 year 2 2 years 1 -30 3 years 2 and 3 . years 3-7 6 years 3-30 . year 3
TABLE 11 ESTIMATED NET PRESENT WORTH ANALYSIS
\
(
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9.0
THE SELECTED REMEDY
EPA has selected Alternative 4 as the cleanup remedy for the Flue
Dust Operable Unit of the Anaconda Smelter Site. The remedy is
made up of the following components:
o
o
Removal and treatment via cement/silicate-based
stabilization of approximately 316,500 cubic yards of
flue dust material located on Smelter Hill;
o
Disposal of treatment residuals in an on-site
engineered repository; and
o
Implementation of institutional controls and monitoring
of the disposal area.
This alternative includes the removal of all flue dust
located. on Smelter Hill (316,500 cubic yards), including flue
dust in the Main Flue. This includes the removal of soils
adjacent to the flue dust that contain visually distinct flue
dust in concentrations greater than concentrations of
contaminants in surrounding soils. Confirmation sampling of
arsenic and cadmium would be required to ensure adequate removal
of flue dust materials. Cleanup of remaining soils will be
evaluated under the Smelter Hill Operable Unit. Some RCRA
closure requirements 40 CFR S 264.258 and ARM S 16.44.702 would
be relevant and appropriate to stabilize the site. Final closure
of the nine flue dust locations is not within the scope of this
project but rather to be determined under the Smelter Hill
Operable Unit.
Conventional earthmoving equipment such as front-end loaders
will be used to excavate the above grade flue dust materials.
Subgrade excavation of the Main Flue will be accomplished using
equipment such as an excavator. Dust suppression and air
monitoring will be required during all flue dust excavation and
transportation activities. There will be no transport of flue
dust on public roads.
The flue dust will be treated at each of the nine flue dust
locations with a mobile crusher and cement batch plant. Large
debris (metal and wood) which cannot be crushed will be separated
and placed in the repository in a manner to prevent potential
damage to the repository liner~ The flue dust will be treate~ to .
render the material non-hazardous by meeting RCRA TCLP regulatory
limits (Maximum Concentration of Contaminants for the Toxicity
Characteristic, ARM S 16.44.324. The flue dust will be treated
in accordance with 40 CFR Subpart X, as incorporated into ARM S
16.44.702, standards for a treatment unit. The specific process
will be determined in the Remedial Design Phase through
engineering~design and analysis. The processed material will
then be transported to an onsite repository for disposal. Dust
30
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Suppression and air monitoring would be required.
Treatability testing indicated that the residue product will
meet RCRA TCLP regulatory limits and that the mobility of
contaminants of concern could be reduced up to 99%.
Because it is expected that treatment of the flue dust will
render the material non-hazardous, this alternative will not
involve the disposal of a RCRA regulated waste, and'RCRA Subtitle
C requirements are not applicable. However, RCRA Subtitle C
requirements have been determined to be relevant and appropriate
to the type of substances being managed. The repository will be
designed and constructed in accordance with the requirements
specified in the Montana Solid Waste Management Act; RCRA
Subtitle D and selected RCRA Subtitle Crequirements and will
include among other things, a liner system, leachate control,
impermeable cap and monitoring. The liner system will be
designed and constructed to prevent the migration of contaminants
out of the repository into underlying soils or groundwater and
will include a leachate collection and removal system. The cap
will be designed and constructed to promote drainage, minimize
erosion of the cover, and provide long-term minimization of
migration of liquids through the underlying contaminated soils.
Consistent with the requirements of 40 CFR 9 264.117, as
incorporated into ARM 9 16.44.702, long-term operation and
maintenance would be conducted to monitor the groundwater around
the repository and to ensure the integrity of the cap.
The repository will be located east of the stack near the
FDS facility shown in Figure 4. This site was identified as
Potential Siting Area (PSA) #9 in the Anaconda Smelter NPL Site
Repository Siting Analysis and is located on the eastern slope of
Smelter Hill, west of Mill Creek. This site was selected over
others because of its depth to groundwater, low transportation
impacts, favorable soils properties (attenuation capacity),
constructability, and favorable institutional controls such as
zoning and restricted access. The site is consistent with the
Anaconda-Deer Lodge County Comprehensive Master Plan.
The repository will be protected with institutional controls
which include site access and land use restrictions. A
monitoring program for the repository will include visual
inspection, appropriate maintenance activities, and groundwater
monitoring. Site access and land use restrictions will begin
implemented immediately. Additional institutional controls may'
be imposed in ROD's for other operable units. Groundwater
monitoring will begin upon implementation of the remedy.
Successful excavation, treatment and placement of the
treated flue dust material in an onsite engineered repository is
expected to. reduce contamination levels at the flue dust
locations to concentrations equivalent in surrounding soils and
31
-------
FIGURE 4
LOCATION OF ONSITE WASTE REPOSITORY
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ORIGINAL
-------
effectively reduce the risk of flue dust contaminant release from
the repository. Remaining risk will be addressed in the Smelter
Hill Operable Unit. Risk reduction for the flue dust remedy was
not quantified because contamination from flue dust cannot be
separated from contamination remaining on site. However, it is
anticipated that this remedy will contribute to the overall
reduction of risk on the site to levels satisfying future
remediation goals.
The estimated capital cost of this alternative is
$25,338,000, with annual O&M costs estimated to be $10,000.
Detailed costs are shown on Table 12. The estimated time to
implement this remedy and meet the cleanup requirements is
approximately three years. Work would be seasonal and would
continue each year for as long as Possible under the given
weather conditions. The repository would be constructed during
the first operating season and individual cells would be closed
each field season.
The remedial design will determine the specific
stabilization process necessary to meet the remediation goals.
Additional testing of processes may be necessary to determine the
specific process or optimum stabilization formula. Some
modifications or refinements may be made to the remedy during
remedial design and construction. Such modifications or
refinements would reflect results of the engineering design
process.
General remediation goals ~nclude the following:
1) Removal of all flue dust materials located on Smelter
Hill (approximately 316,500 cubic yards) to equivalent
concentration levels found in adjacent soils. Remaining
soils will be addressed under the Smelter Hill Operable
Unit;
2) Treatment of flue dust via cement/silicate-based
stabilization to render the material non-hazardous by
meeting RCRA reg~latory limits (Maximum Concentration of
Contaminants for the Toxicity Characteristic, ARM!
16.44.324, as determined by the Toxicity Characteristic
Leaching Procedure.
Arsenic
Cadmium
Lead
. 5.0 mg/l
1.0 mg/l
5.0 mg/l
These RCRA regulatory limits were determined through
consideration of Best Demonstrated Available Technologies
(BDAT). In addition, the treate~ residual material will be
expected to be stable over the long term. Long-term
stability criteria (i.e. leaching, durability, permeability
32
-------
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ORIG'NAL
b
-------
and strength) will be determined in the remedial design
phase;
3) Containment of treatment residues in an engineered
repository designed and constructed in accordance with the
requirements specified in the Montana Solid Waste Management
Act, RCRA Subtitle 0 and selected RCRA Subtitle C
requirements, that at a minimum include: a liner system,
leachate control, impermeable cap and monitoring. The liner
system will be designed and constructed to prevent the
migration of contaminants out of the repository into
underlying soils or groundwater and would include a leachate
collection and removal system. The cap will be designed and
constructed to promote drainage, minimize erosion of the
cover, and provide long-term minimization of migration of
liquids through the underlying contaminated soils; and
4) Long-term operation and maintenance, consistent with the
requirements of 40 CFR Section 264.117, as incorporated into
ARM Section 16.44.702, will be conducted to monitor the
groundwater around the repository and to ensure the
integrity of the cap.
More specific remediation goals and considerations include
the following:
A. .
Engineered Waste repository: The repository for the treated
flue dust materials will he designed and operated
exclusively for the treated wastes. A design incorporating
RCRA Subtitle 0 requirements plus certain criteria included
in the RCRA Subtitle C regulations will be necessary to
assure that the contaminants remaining in the treated wastes
are not released into the environment.
1 .
The repository will be designed specifically for the
physical and chemical characteristics of treated flue
dust.
2.
The repository will include
clay or composite liner and
meeting the criteria listed
264.301(a), as incorporated
at a minimum a single soil,
leachate collection system
in 40 CFR Section
into ARM Section 16.44.702.
3.
Run-on and run-off systems and operating criteria ~ill'
meet the requirements of 40 CFR SS 264.301(f),(g) and
(h) as incorporated into ARM S 16.44.702.
"
33
-------
4 .
Construction and operatic~ of the repository will
include control of wind dispersal of particulate matter
(40 CFR ~ 264.301(i), as incorporated into ARM ~
16.44.702) and inspection of the liner, run-on and run-
off systems, and the leachate collection and removal
system (40 CFR ~ 264.303, as incorporated into ARM S
16.44.702).
5.
Monitoring and protection of the groundwater will be
addressed as described in 40 CFR Part 264, Subpart F,
as incorporated into ARM 9 16.44.702.
6.
B.
Closure and post-closure care of the repository will
include the criteria listed in 40 CFR S 264.310 and
Subpart G, as incorporated into ARM ~ 16.44.702.
Stabilized flue dust: Remedial Design will consider the
following characteristics in determining the specific
process or formula to treat flue dust materials. The
variability of the flue dust materials and the difficulties
of quality control due to this variability will also be
considered in the design of the treatment process. The
proposed design of the repository for the treated wastes
will also influence the required characteristics of the in-
place wastes.
1 .
Leachability: The in-place treated waste will meet the
RCRA TCLP regulatory limits. The permeability and
homogeneity of any monolithic waste placements will be
considered in developing methods to test the in-place
waste or to otherwise verify the leachability of the
in-place waste.
2.
Free liquid content of waste: No liquid may be exuded
from the in-place waste under the maximum loading
proposed in the repository design.
3.
Physical stability of waste under burial conditions:
The in-place waste should be able to support
construction equipment used in disposal of the waste.
Operation of equipment on the in-place waste should not
affect the design properties necessary to meet TCLP.
The waste should not subside over the long term,
causing final cover collapse or failure.
4.
Reactivity of waste: The treated waste should be
nonreactive.
5.
Ignitability: The treated waste should be
nonpyrophoric.
34
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6.
Susceptibility to bio~egradation: The treated waste
should not support microbial growth.
7.
Strength or bearing capacity: The in-place waste should
be able to support the weight of the waste above plus
the final cover without losing design properties.
8.
Permeability: Any in-place monolithic waste masses
should have adequate impermeability and structural
integrity (e.g. absence of cracks and voids) to limit
mobility in the treated wastes and limit transfer of
contaminants from the solid mass to leaching water.
9.
Durability: The in-place wastes should be resistant to
freeze/thaw and wet/dry cycles to the extent expected
in the design and operation of the repository. This
includes the period between placement of the wastes and
.final covering of the entire repository. The projected
three year duration of the treatment project will be
considered.
Stabilization of flue dust is consistent with BOAT and would
appear to satisfy future land disposal restrictions. An
engineered repository will provide sufficient long-term waste
management and additional protection to human health and the
environment. Stabilization and containment of waste materials is
consistent with the overall cleanup objectives for the site.
Treatment of flue dust to meet remediation goals is fully
expected. However, if the remedial design phase indicates that
treatment via stabilization will not produce residue materials
that meet the desired cleanup criteria, the flue dust would still
be treated via stabilization and placed in a repository designed
to meet all RCRA Subtitle C requirements. Additionally, if at
any time confirmation sampling indicates that treated flue dust
is a hazardous waste, the hazardous waste will be placed in a
repository designed to meet all RCRA Subtitle C requirements.
The selection of this remedy is based upon the comparative
analysis of alternatives presented in the previous section. This
cleanup action will achieve substantial risk reduction through
the immobilization of contaminant, including arsenic, cadmium and
lead and by containment of the treated material in an engineered
on site repository. It will provide a high degree of long-term
protection of human health and the environment and will attain.
ARARs. This remedy achieves risk reduction quickly using a
demonstrated technology which will be easily implemented. This
remedy is cost effective and is consistent with the overall
cleanup objectives for the Anaconda Smelter Site. Based on the
information available at this time, EPA believes this remedy
provides the best balance of trade-offs among the other
alternatives with respect to the nine evaluation criteria.
35
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10.0 STATUTORY DETERMINATIONS
u
EPA's primary responsibility at Superfund sites is to select
remedial actions that are protective of human health and the
environment. CERCLA also requires 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 also be cost effective and utilize permanent
treatment technologies or resource recovery technologies to the
maximum extent practicable. CERCLA also contains a preference
for remedies that include treatment as a principle element. The
following sections discuss how the selected remedy for the flue
dust materials at the Anaconda Smelter site meets these statutory
requirements
10.1 Protection of Human Health and the Environment
The selected remedy protects human health and the
environment through the immobilization of contaminants, including
arsenic, cadmium and lead and through the containment of treated
material in an engineered onsite repository.
Through source removal, the exposure pathways to potential
receptors are interrupted. Stabilization and containment will
eliminate the threat of exposure to most contaminants from direct
contact, the inhalation route and ingestion of soil and
gro~ndwater. Successful excavation, and disposal of treated
material in an engineered repository is expected to reduce
contamination levels at the flue dust piles to concentrations
equivalent to adjacent soils. Containment of treated material
will effectively reduce the risk of flue dust contaminant release
to the environment. The repository will be capped and closed to
reduce the likelihood of contaminant migration.
There are no short-term threats associated with the selected
remedy that cannot be readily controlled through applicable
occupational health requirements.
10.2 Compliance With Applicable or Relevant and Appropriate
Requirements
The selected remedy of removal, onsite cement/silicate
stabilization and disposal of treated material in an onsite
repository will comply with all applicable or relevant and
appropriate contaminant- action- and location-specific
requirements (ARARs). The ARARs for the selected remedy are
specified in Attachment 1.
based
~
36
-------
10.3 Cost Effectiveness
The selected remedy is cost effective because it has been
determined to provide overall effectiveness proportional to its
costs, the net present worth value being $21,866,000. The
estimated costs of the selected remedy are within an order of
magnitude of (less than four times) the cost associated with
disposal of untreated flue dust in a full RCRA Subtitle C
repository, and yet the selected remedy assures a much higher
degree of certainty that the remedy w~ll be effective in the
long-term due to significant reduction in contaminant mobility of
the flue dust.
Although metals recovery in Alternative 6 was shown to be
similar in cost, it had a much higher degree of uncertainty
potentially doubling the cost of the remedy. Also, a higher
degree of uncertainty existed with its success.
10.4 Utilization of Permanent Solutions and Alternative
Treatment Technologies or Resource Recovery
Technologies to the Maximum Extent Practicable
EPA has determined that the selected remedy represents the
maximum extent to which permanent solutions and treatment
technologies can be utilized in a cost effective manner for the
Flue Dust Operable Unit at the Anaconda Smelter Site. Of those
alternatives that are protective of human health and the
environment and comply with ARARs, the EPA has determined that
this selected remedy provides the best balance of tradeoffs in
terms of long-term effectiveness and permanence, reduction in
toxicity, mobility or volume, through treatment, short-term
effectiveness, implementability, cost and considers the statutory
preference for treatment as a principal element, State and
community acceptance:
The selected remedy treats the principal threats posed by
the flue dust, significantly reducing the mobility of the
contaminants of concern. The selected remedy is more effective
than all other treatment alternatives in the short-term,
requiring two to three years to complete compared to seven to ten
years for metals removal. The implementability of the selected
remedy is comparable to the nontreatment options and
significantly better than metals removal. The selected remedy is
cost effective in comparison to metals removal but with a higher
degree of certainty, and is much less than some metals removal.
and off-site disposal alternatives.
~
The selection of treatment of flue dust is consistent with
EPA expectations that indicate that highly toxic and mobile
wastes are a priority for treatment and that treatment is often
necessary ~o ensure long-term effectiveness of the remedy. Since
stabilization and metals removal with stabilization are
37
-------
c
comparable with respect to long-term effectiveness and the
toxicity and mobility reductions achieved, the major tradeoffs
that provide the basis for this selection decision are short-term
effectiveness, implementability and cost. The selected remedy
can be implemented more quickly, with less difficulty and at less
cost than the metals removal options and is therefore determined
to be the most appropriate solution for the flue dust at the
Anaconda Smelter site.
10.5 Preference for treatment as a Principal Element
By treating the flue dust material through cement/silicate
based stabilization, the selected remedy addresses one of the
principal threats posed by the site through use of treatment and
permanent solutions to the maximum extent possible. Therefore,
th~ statutory ~reference for remedies that employ treatment as a
principal element is satisfied.
38
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ATTACHMENT 1
APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS, STANDARDS, CONTROLS, CRITERIA, OR LIMITATIONS
FOR THE ANACONDA SMELTER SUPERFUND SITE
FLUE DUST OPERABLE UNIT
-------
ATTACHMENT 1
APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS, STANDARDS, CONTROLS, CRITERIA, OR LIMITATIONS
FOR THE ANACONDA SMELTER SUPERFUND SITE -
FLUE DUST OPERABLE UNIT
Section 121(d) of CERCLA, 42 U.S.C. Section 9621(d~, the National
Oil and Hazardous Substances Pollution Contingency Plan (the
NCP), 40 C.F.R. Part 300 (1990), and guidance and policy issued
by the Environmental Protection Agency (EPA) require that
remedial actions under CERCLA comply with substantive provisions"
of applicable or relevant and appropriate standards,
requirements, criteria, or limitations from state and federal
environmental laws and state facility siting laws at the
completion of the remedial action, and/or during the
implementation of the remedial action, unless a waiver is
granted. These requirements are threshold standards that any
selected remedy must meet. The Feasibility Study for the Flue
Dust operable unit proposed a set of such requirements, and gave
justification for identifying the proposed requirements. After
consideration 6£ public comments on the proposed requirements,
and further review of applicable guidance and standards,
including the NCP, the following is the final list of ARARs for
the Flue Dust operable unit Record of Decision.
Each ARAR or group of related ARARs is identified by statutory or
regulatory citation, followed by an explanation of the ARAR,
including a compliance description which addresses how and when
compliance with the ARAR will be measured (some ARARs will govern
the conduct of the implementation of the remedial action, some
will govern the measure of success of the remedial action, and
some will do both). Some ARARs will be pertinent to the waste
repository while some will be pertinent both to the repository as
well as flue dust in the nine waste piles and the collapsed main
flue.
Also contained in this list are pOlicies, guidance or other
sources of information which are "to be considered" during the
selection and implementation of the ROD. Although not
enforceable requirements, these documents and laws are important
sources of information which EPA and the State 'of Montana
Department of Health and Environmental Sciences (MDHES) referred
to during selection of the remedy, especially in regard to the
evaluation of public health and environmental risks; or which
will be referred to as appropriate during evaluation and approval
of various activities during the ROD implementation.
-------
Finally, this list contains other legal provisions or
requirements which should be complied with during the
implementation of this ROD. '
Responses to comments on the proposed ARARs and further
discussion of EPA's rationale for selecting these ARARs is
contained in the responsiveness summary attached to this ROD.
The portions of the Feasibility Study (FS) which address ARARs,
the ARARs section of the responsiveness summary, and applicable
EPA guidance, policy, regulation, and statutory authority, form
the basis for the final selection of ARARs contained in this
list.
ARARs are contaminant, location, or action specific. Contaminant
specific requirements address chemical or physical
characteristics of compounds or substances on sites. These
values establish acceptable amounts or concentrations of
chemicals which may be found in, or discharged to, the ambient
environment.
Location specific requirements are restrictions placed upon the
concentrations of hazardous substances or the conduct of cleanup
activities because they are in specific locations. Location
specific ARA~s relate to the geographic or phy,sical positions of
sites, rather than to the nature of the contaminants at sites.
Action specific requirements are usually technology based or
activity based 'requirements or limitations on actions taken with
respect to hazardous substances, pollutants or contaminants. A
given cleanup activity may trigger an action specific
requirement. Such requirements do not themselves determine the
cleanup alternative, but define how chosen cleanup methods should
be performed.
Many requirements listed h~re are promulgated as identical or
near identical requirements in both federal and state law,
usually pursuant to delegated environmental programs administered
by EPA and the state, such as the requirements of the federal
Clean Water Act and the Montana Water Quality Act. The preamble
to the NCP states that such a situation results in citation to
the state provision as the more stringent standard but treatment
of the provision as a federal requirement.
2
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1.
B.
Contaminant Specific ARARs.
A.
Air.
1.
ARARs pertinent to areas from which flue dust will
be excavated.
Final remediation of air at areas from which flue
dust will be excavated is not within the scope of
the Flue Dust operable unit remedial action. It
is not anticipated that existing air quality will
be adversely impacted after excavation of flue
dust, as all flue dust will be removed. Action
specific requirements for air set forth below at
Section III.B. will assure that air quality is not
adversely affected during excavation and treatment
of flue dust. EPA's expectation is that final
contaminant specific air standards for excavated
areas will be ARARs at the time of the Smelter
Hill operable unit ("OU") remedial action. The
waste repository will be designed and will be
expected to contribute efficiently to final
compliance with all air requirements as provided
below at Section III.C.4.
2.
See air ARARs set forth for the waste repository
at Section III.C.4., below.
Water.
1 .
ARARs pertinent to areas from which flue dust will
be excavated.
Remediation of ground and surface water in areas -
from which flue dust will be excavated is not
within the scope of the Flue Dust operable unit
.remedial action. Ground and surface water were
not sampled or studied as part of the Flue Dust
RI/FS and it is not anticipated that ground or
surface water will be adversely impacted in any
way as a result of remedial activity to be
implemented. Therefore, ground and surface water
standards for excavated areas are not set forth
herein as ARARs. EPA's expectation is that these
requirements will be ARARs at the time of the..
Smelter Hill operable unit remedial action.
Should remedial activity in some unforeseen way
impact ground or surface water, then EPA reserves
the right to reexamine water ARARs for the
excavated areas and to look to these provisions in
dealing with impacts to.affected waters.
3
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I:.
A.
2.
See water ARARs set forth for the waste repository
at Section III.C.3., below.
Location Specific ARARs.
The statutes and regulations set forth below relate to
the preservation of certain cultural, historic, natural
or other national resources which may be adversely
affected by the removal action. They require that such
resources be identified, and that steps be taken to
minimize the impact of the remedial action upon any
such resources.
1 .
National Historic Preservation Act, 16 U.S.C. !
470, 40 C. F. R. S 6. 301 ( b), 36 C. F . R. Part 800.
Cultural resources associated with the Flue Dust
operable unit must be identified and the impact of
remedial action upon these resources determined.
Based upon current information, EPA has previously
.determined that the flue dust locations are not
eligible for listing on the National Register of
Historic Places. However, The State Historic
Preservation Office has not concurred with this
determination and has indicated ~hat there is
potential for Smelter Hill to be a historic
district.
2 .
Archaeological and Historic Preservation Act, 16
U.S.C. S 469, 40 C.F.R. S 6.301(c).
This requires the preservation of data cqncerning
scientific, prehistoric, or archaeological
artifacts.
3.
Endangered Species Act, 16 U.S.C. S 1531, 40
C.F.R. S 6.302(h), 50 C.F.R. Parts 17 and 402.
This statute and implementing regulations provide
that federal activity not jeopardize the continued
existence of any threatened or endangered species.
Continued consultation with the U.S. Fish and
Wildlife Service will be required. However, based
upon available information and consultation with
the U.S. Fish and Wildlife Service, there are 'no.
threatened or endangered species with the Smelter
project area. However, bald eagles and peregrine
falcons may occur within or near the site as
migrants and/or winter residents.
4
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,,'
B.
2.
4.
40 C.F.R. Part 6, Appendix A. It should be noted
that it is not expected that this remedial action
will affect any wetlands, nor is any part of this
action expected to take place within a floodplain.
However, if wetlands are potentially affected, the
following requirements would apply.
a.
Wetlands Protection, Executive Order No.
11990.
This requires the avoidance of adverse
impacts to wetlands and the avoidance of
construction in wetlands if practicable. In
addition, the action shall result in "no net
loss" of wetlands.
b.
Floodplain Manaqement, Executive Order No.
11988.
Facilities within a 1DO year floodplain must
be designed, constructed, and maintained to
avoid washout. It is not expected that any
portion of this remedial action will take
place within a 100 year floodplain.
State of Montana requirements.
1 .
MCA SS 76-5-402, -403, and -404; ARM SS 36.15.216,
-601 through -606, -701 and -703.
Floodplain and floodway management, these
provisions out~ine uses prohibited and permitted
within floodway, flood fringe, and floodplain. It
is not expected that any portion of this remedial
action will take place within a floodplain.
ARM S 16.44.702, incorporatinq by reference 40
C. F. R. S 264. 1 8 ( a) and (b).
Facilities where hazardous waste is stored,
treated or disposed may not be placed within 200
feet of a fault. Facilities located within a 100
year floodplain must meet the requirements of this
section. It is not. expected that any portion of
this remedial action will take place within a.10D
year floodplain.
5
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III. Action Specific ARARs.
A.
ARARs pertinent to areas from which flue dust will be
removed, including the waste piles, the flue dust
storage area, and the main flue.
1 .
40 C.F.R. 264 Subpart G, and 40 C.F.R. S 264.258,
as incorporated by ARM S 16.44.702. Closure and
post closure care for waste piles.
The areas from which waste is removed shall be
"closed" with flue dust removed. Waste residues,
and contaminated container system components,
subsoils, structures, and equipment must be
removed and managed as hazardous waste.
Concentrations of contaminants in subsoils may not
be greater than contaminant concentrations in
surrounding soils. Final closure is beyond the
scope of this remedial action and will occur at
the time of the Smelter Hill remedial action.
2.
Requirements of the Montana Strip and Underqround
Mine Reclamation Act, MCA S 82-4-201, et seq., and
regulations promulqated thereunder.
The substantive portions of the following
regulatory provisions, to the extent they deal
with grading requirements, erosion control, and
stabilization measures that will be useful in
securing the excavation sites in the period before
final remedial action is taken are hereby
identified as ARARs. Revegetation and final
reclamation of the excavated areas will occur at
the time of the Smelter Hill remedial action. The
provisions are deemed to be ARARs for the Flue
Dust Operable Unit: MCA S .82-4-231, ARM SS
26.4.501, -SOlA, -520, -631, -633, -636, -638,
-640, -641, -642, -644, -719, and -761. All
regulatory requirements under MCA 992-4-201 will
be ARARs for the Smelter Hill Operable Unit.
These are. set forth in Section IV. C.
6
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B.
ARARs pertinent to excavation, treatment, and transport
of flue dust to the waste repository.
1 .
Air requirements.
Clean Air Act, 42 U.S.C. S 7401, et seq.
Montana's delegated air program, see the Clean Air
Act of Montana, M.C.A. S 75-2-101~t seq., is
authorized under the Clean Air Act, 42 U.S.C.
7409, as part of a State Implementation Plan
approved by EPA. See 52 C.F.R. Part 52 Subpart
BS. MCA S 75-2-102 provides, among other things,
that air quality is to be maintained so as to
protect human health and safety and prevent injury
to animal and plant life. Montana air
requirements closely parallel federal
requirements. Because the state standards are
part of a delegated or authorized program under
the Clean Air Act, the state requirements are
identified as the ARARs to be complied with. The
following requirements must be complied with
during excavation, treatment, and transport of,
flue dust. .
a.
ARM S 1 6 . 8 . 1 4 a 1 ( 2 ), (3), and (4).
Airborne particulate matter. There shall be
no production, handling, transportation, or
storage of any material, use of any street,
road, or parking lot, or operation of a
construction site or demolition project
unless reasonable precautions are taken to
control emissions of airborne particles.
emissions shall not exhibit an opacity
exceeding 20% or greater averaged over 6
minutes. This provision must be complied
with at the excavated areas as well as at the
waste repository.
b.
ARM ~ 16.8.1404(2).
Visible Air Contaminants. Emissions into the
outdoor atmosphere shall not exhibit an
opacity of 20% or greater averaged over 6. ,
consecutive minutes. This provision must be
complied with at the excavated areas as well
as at the waste repository.
7
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2.
c.
c.
ARM 9 16.8.1427.
Nuisance or odor bearing gases. Gases,
vapors and dusts must be controlled such that
no public nuisance is caused. Compliance
with this provision at the excavated areas
and the waste repository will assure that no
public nuisance occurs.
--~ -
d.
ARM 9 26.4.761.
Fugitive dust control measures such as 1)
watering, stabilization, or paving of roads,
2) vehicle speed restrictions, 3)
stabilization of surface areas adjoining
roads, 4) restriction of travel on other than
authorized roads, 5) enclosing, covering,
watering, or otherwise treating loaded haul
trucks, 6) minimizing area of disturbed land,
and 7) revegetation must be planned and
implemented. This provision must be complied
with at the excavated areas as well as at the
waste repository.
Transportation requirements
a.
ARM 9 16.44.512.
Discharges of flue dust or treated flue dust
discharged during transportation shall be .
cleaned up to the extent they no longer
present a hazard to human health or the
environment.
b.
ARM S 16.44.525.
Entry of persons or animals to any area where
flue dust or treated flue dust is transferred
or temporarily stored shall be prevented.
ARM S 16.527(2).
Any containers used for transporting flue
dust or treated flue dust must be handled in
a way which minimizes the risk of leaks or.
spills.
8
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~,,:
3 .
RCRA Subtitle C requirements.
a.
ARM 9 16.44.324.
Treated flue dust material shall not exhibit
the characteristic of toxicity.
b.
. ARM 9 16.44.702, incorporating by reference,
40 C.F.R. 9 264.144
Access to the treatment unit shall be
controlled.
b.
ARM 9 16.44.702, incorporating by reference,
40 C.F.R. Part 264 Subpart XX
The treatment unit must be designed to
prevent any releases that may have adverse
effects on human health or the environment
due to migration of waste constituents into
groundwater, surface water, wetlands, or air.
C.
ARARs pertinent to design, construction, and operation
of the waste repository. The waste repository shall be
designed to meet the requirements set forth below.
, .
Resource Conservation and Recovery Act ("RCRA"),
42 U.S.C. 6901, et seq., ARARs.
a.
ARM S 16.44.702, incorporating by reference,
40 C.F.R. Part 264.257. Criteria for
Classification of Solid Waste Disposal
Facilities and Practices.
i.
40 C.F.R. S 257.3-1.
Washout of solid waste in facilities in
a floodplain posing a hazard to human
life, wildlife, or land or water
resources may not occur.
ii.
40 C.F.R. S 257.3-2.
Facilities may not contribute to the
taking of endangered species or the
endangering of critical habitat of
endangered species.
9
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iii.
40 C.F.R. S 257.3-3.
A facility may not cause a discharge of
pollutants, dredged or fill material,
into waters of the'United States in
violation of sections 402 and 404 of the
Clean Water Act, as amended, and may not
cause nonpoint source pollution, in
violation of section 208 of the Clean
Water Act, as amended.
iv.
40 C.F.R. S 257.3-4.
A facility may not contaminate an
underground source of drinking water
beyond the solid waste boundary.
v.
40 C.F.R. S 257.3-8(d).
Access to a facility shall be controlled
so as to prevent exposure of the public
to potential health and safety hazards
at the site.
b.
RCRA Subtitle C ARARs.
It is expected that the treated flue dust
will not be a characteristic hazardous waste.
However, if treated flue dust remains a
characteristic hazardous waste, then EPA
reserves the right to reexamine all RCRA
Subtitle C requirements.
1 .
ARM S 16.44.702, incorporating by
reference, 40 C.F.R. 264 Subpart F.
General Facility Standards.
The waste repository must be designed
consistent with the following
requirements. Final compliance with
these standards will be required at the
time of the Smelter Hill Operable Unit.
a.
ARM g 16.44.702, incorporating by
reference, 40 C.F.R. SS 264.92,.
.93. and .94. Groundwater
protection standards at 40 C.F.R.
264.94 shall be complied with.
1 0
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'u
b.
c.
ARM S 16.44.702, incorporating by
reference, 40 C.F.R. S 264.97.
General groundwater monitoring
requirements shall be complied
with.
ARM S 16.44.702, incorporatinq by
reference, 40 C.F.R. S 264.98.
Requirements for monitoring and
detecting indicator parameters
shall be complied with.
2.
Closure requirements.
a.
b.
c.
ARM S 16.44.702, incorporatinq by
reference, 40 C.F.R. 264.111,
This provides that the owner or
operator of a hazardous waste
management facility must close
the facility in a way that.
minimizes the need for further
maintenance, and controls or
eliminates the leaching or escape
of hazardous waste or its
constituents, leachate, or runoff
to the extent necessary to
protect human health and the
environment.
ARM S 16.44.702, incorporating by
reference, 40 C.F.R. S 264.117,
This provision incorporates
monitoring requirements in Part
264, including those mentioned at
Part 264.97 and Part 264.303. It
governs the length of the post-
closure care period, permits a
lengthened security period, and
prohibits any use of the property
which would disturb the integrity
of the management facility. .
ARM S 16.44.702, incorporating by
reference, 40 C.F.R. S 264.310;
This specifies requirements Lor
caps, maintenance, and monitoring
after closure.
1 1
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3.
40 C.F.R. 264.301, as incorporated by
ARM S 16.44.702. Design and operating
requirements for landfills.
a.
40 C.F.R. 264.301(a). This
provides for a single liner and
leachate collection and removal
system.
b.
40 C.F.R. 264.301(f). This
requires a run-on control system.
c.
40 C.F.R. 264.301(g). This
requires a run-off management
system.
d.
40 C. F . R. 264. 301 ( h ) . Th i s
requires prudent management of
facilities for collection and
holding of run-on and run-off.
e.
40 C.F.R. 264.301(i). This
requires that wind dispersal of
particulate matter be controlled.
2.
State of Montana solid waste requirements.
MCA S 75-10-212, and ARM SS 16.14.505, -520, and -
523.
Disposal of solid waste except as provided by the
Montana Solid Waste Management Act is prohibited;
solid waste disposal sites must be located outside
of 100-year floodplain and in areas that will
prevent pollution of ground and surface waters and
public and private water supplies; drainage
structures must be installed where necessary to
prevent surface runoff from entering disposal
areas; solid waste disposal must be in areas
which can be effectively maintained; and solid
waste must be transported in such a way as to
prevent its discharge, dumping spilling or leaking
from the transport vehicle.
.,
1 2
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'"
3 .
Water quality requirements.
a.
Surface water.
1 .
Montana Water Quality Act, MCA S 75-5-
303, and implementing regulati~ns at ARM
16.20.604, -618, -631, -632, -633, -702,
and -703.
These provisions establish Montana's
surface water standards and
nondegradation policy. The waste
repository must be designed so as to
comply with these requirements.
2.
MCA S 75-5-605.
The waste repository must be designed so
as not to cause pollution of state
waters.
b.
Groundwater.
. .
The waste repository may not violate the
requirements below.
1 .
MCA S 85-2-505.
2.
Wasting or contamination of groundwater
is prohibited.
ARM SS 16.20.1002, -1003, and -1011.
These sections, among other things,
adopt MCLs as standards for groundwater,
and set out the state's nondegradation
policy for groundwater.
c.
Drinking water.
MCA S 75-6-112, ARM SS 16.20.203, and -205.
These prohibit discharges which cause
pollution to state waters which are sources
for public water systems, and set MCLs
(maximum contaminant levels) for community
water systems. The waste repository shall be
designed so as not to violate these
requirements.
1 3
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4 .
Air quality requirements.
Clean Air Act, 42 U.S.C. S 7401, et seq.
Montana's delegated air program, see the Clean Air
Act of Montana, M.C.A. S 75-2-101~t seq., is
authorized under the Clean Air Act, 42 U.S.C.
7409, as part of a State Implementation Plan
approved by EPA. See 52 C.F.R. Part 52 Subpart
BB. Montana air requirements closely parallel
federal requirements. Because the state standards
are part of a delegated or authorized program
under the Clean Air Act, the state requirements
are identified as the ARARs to be complied with.
The waste repository must be designed so as to be
capable of meeting the following requirements.
a.
ARM S 16.8.811.
The concentration of carbon monoxide in
ambient air shall not exceed an hourly
average of 23 parts per million or an 8
average of 9 parts per million. This
provision must be complied with at the
excavated areas as well as at the waste
repository.
hour
b.
ARM S 16.8.815.
The concentration of lead in ambient air
shall not exceed a 90 day average of 1.5
micrograms per cubic meter of air. This
provision must be complied with at the
excavated areas as well as at the waste
repository.
c.
ARM S 16.8.818.
Settled particulate shall not exceed a
average of 10 grams per square meter.
provision must be complied with at the
excavated areas as well as at the waste
repository.
30 day
This
1 4
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IV.
d.
ARM 9 16.8.821.
The concentration of PM-l0 in ambient air
shall not exceed a 24 hour average of 150
micrograms per cubic. meter of air and an
annual average of 50 micrograms per cubic
meter of air. This provision must be
complied with at the excavated areas as well
as at the waste repository.
e.
ARM 9 16.8.822.
Visibility; the scattering coefficient shall
not exceed an annual average of 3 X 10-5 per
meter in Class I areas. This shall be
measured at the Class I area nearest to the
location of the Flue Dust au.
f.
ARM 9 16.8.925.
Ambient air increments. This sets the
maximum allowable increases over baseline
concentrations for particulate matter. For
Class I and II areas, respectively, the
maximum annual geometric mean is 5 and 19
ug/m3, and the 24 hour maximums are 10 and 37
ug/m3.
g.
ARM S 16.8.926.
Ambient air limits. This provides that no
concentration of a pollutant may exceed any
state or federal ambient air quality
standard.
h.
During construction of the waste repository,
the requirements set forth at Section
.III.B.l. must be met.
List of Criteria, Advisories and Guidance To Be Considered
A.
Chemical Specific Guidance - For the flue dust
constituents listed at 1., below, based on detected
levels and degree of toxicity, refer to the documents
at IV. A. 2., below, for RfDs and cancer potency slope
factors.
1 .
Flue dust constituents: antimony, arsenic,
beryllium, bismuth, cadmium, chromium, copper,
iron, lead, magnesium, manganese, mercury,
molybdenum, nickel, selenium, silver, and zinc.
15
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2 .
Reference documents:
Health Profiles. Agency for Toxic Substances
and Disease Registry. U.S. Public Health
Service.
Integrated Risk Information Service (IRIS).
EPA. Office of Research and Development.
Health Effects Summary Table. EPA
Environmental Criteria and Assessment Office.
Published Quarterly.
Health Effects Assessments and Health
Advisory Documents. EPA. Office of Research
and Development.
Health Advisories for Drinking Water.
Office of WAter.
EPA.
Water Quality.
EPA.
Office of Water.
B.
General EPA Policy Documents.
Risk Assessment Guidance for Superfund.
Human Health Evaluation Manual, Part A. July
1989. Office of Solid Waste and Emergency
Response.
Risk Assessment Guidance for Superfund.
Environmental Evaluation Manual. 1989.
RCRA Landfill Design - Liner Systems and
Final Cover.
EPA's Ground-Water Protection Strategy.
Guidance on Remedial Actions for Contaminated
Ground Water at Superfund Sites (draft,
October 1986).
Management of Hazardous Waste Leachate.
Guide to Disposal of Chemically Stabilized
and Solidified Waste.
Evaluating Cover Systems for Solid and
Hazardous Waste.
Test Methods for Evaluating Solid Wastes.
Solid Waste Leaching Procedure Manual.
1 6
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.
"
Guidance Manual on Closure and Post-Closure
Interim Standards.
Handbook for Stabilization/Solidification of
Hazardous Wastes.
C.
Regulations and standards which are not ARARs for the
Flue Dust Operable Unit, but which may contain
information to be considered towards the final site
disposition or management of treated waste.
1 .
State of Montana statutory provisions.
MCA 9 50-78-101, et seg., Employee and
Community Hazardous Chemical Information Act.
MCA 9 87-5-501, et seq., Stream Protection
Act.
MCA 9 75-10-401, et seq., Montana Hazardous
Waste and Underground Storage Tank Act.
MCA 9 75-10-201, et seq., Montana Solid Waste
Management Act.
MCA 9 85-2-501, et seq., Groundwater.
MCA 9 75-20-101, et seg., Montana Major
Facility Siting Act.
2.
State of Montana regulatory provisions.
ARM 9 26.4.311, air monitoring for fugitive
dust.
ARM 9 26.4.312, plan for minimizing fish and
wildlife impacts.
ARM 9 26.4.313, establish a reclamation plan.
ARM 9 26.4.314, establish informational needs
to preserve and protect the hydrologic
balance.
ARM 9 26.4.725, establishes a period of
performance when a bond covers revegetation
plantings.
ARM 99 36.7.2502, 2503, 2504 and 2505,
setting siting criteria under the Montana
Major Facility Siting Act.
1 7
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3.
The following provisions will be ARARs for the
Smelter Hill Operable Unit. Actions taken at the
Flue Dust Operable Unit shall not be inconsistent
with these requirements.
The Montana Strip and Underground Mine
Reclamation Act, MCA S 82-4-201, et sag., and
regulations promulgated thereunder.
Final backfilling, contouring, and
revegetation is expected to occur at the time
of the Smelter Hill Operable Unit and
substantive portions of the following
regulatory provisions will therefore be ARARs
for the Smelter Hill Operable Unit. The
provisions are: ARM SS 26.4.501, -SOlA,
-504, -505, -520, -631, -633, -634, -636,
-638, -639, -640, -641, -642, -644, -703,
-711, -713, -714, -716, -717, -718, -719,
-721, -751, and -761.
18
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"
ATTACHMENT 2
TREATABILITY TESTING DATA RESULTS
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TREATABILITY TESTING DATA RESULTS
STABILIZATION/FIXATION TESTING
Cement- and silicate-based stabilization/fixation technologies
have been demonstrated to be effective in reducing the toxicity and
mobility of metals-containing materials similar to the flue dust of the
operable unit. Process- and material--specific treatability data were
required to confirm that the TCLP and EP Toxicity characteristics can
be removed from the flue dust materials through stabilization/fixation
treatment.
Cement-based treatment was evaluated by HAZCON Engineering, Inc.
(HAZCON) in Brookshire, Texas; Dames & Moore in Denver, Colorado; and
MSE, Inc. (MSE) in Butte, Montana. Silicate-based treatment was
evaluated at CHEMFIX Environmental Services, Inc. (CES) in Metairie,
Louisiana.
HAZCON Stabilization/Fixation Technology
Cement-based stabilization/fixation treatment involves mixing
excavated ilue dust material with a combination of portland cement (PC)
or cement kiln dust (CKD), hydrated lime (HL), and deionized water.
The HAZCON process includes the addition of HAZCON's patented chemical
reagent "Chloranan" to the cement mixture. Formulations can be
adjusted to produce either a treated product resembling a crumbly soil-
like material or a monolithic solid. Metals are chemically bound and
microencapsulated within the cement matrix.
Results confirm that the technology can effectively remove the EP
Toxicity characteristics from the flue dust and that the treated
material, in general, exhibits acceptable UCS and hydraulic
conductivity characteristics for land disposal (Tables 1 and 2).
Optimum formulations have been identified for each of the four
flue dust material types tested (Table 3). Samples of the treated
materials were not submitted for TCLP analysis during treatability
testing. Optimum- formulations, with the exception of CPT formulat~ons,
prcduced materials with unconfined compressive strength CUeS) values of
greater than 50 psi. Optimum formulations ~roduced materials with
hydraulic conductivities of less than lxl0- cm/s. Testing was not
adequate for evaluating the effectiveness of the treatment when applied
without the HAZCON patented additive Chloranan.
-------
"
TABLE 1
HAZCON STABILIZATION/FIXATION PHASE II
TESTING CLP-EP TOXICITY RESULTS
eLl' IlAZC08 o~ . 1pOr';
1ulp18 II) 8&8918 m Ift8b8c Aa 8& Cd CI' Ita 119 .. A9
5' IP-C-2 11..1 0.5" 0.435 0.02 0 0.030 0.25 11 0.002 U 0.305 U 0.015 D
n 1P-D-2 111.1 0.1' D 0.U5 It., 0.025 D ..1' 0.021 0.305 D O.OJZ
31 IP--=:-2 nln 1..0' 0.370 0.02 0 0.021 0.25 D 0.002 0 0.305 a 0.015 0
3C I1>-D-Z 111.8 0.1' D 0.302 U.2 0.025 D 11.8 o.on 0.305 11 0.015 11
4~ cn-C-2 111.1 0.1' D 0.lt2 0.02C 0.025 11 0.25 D 0.014 0.305 D 0.015 D
41 CV1'-U-2 11141 0.1' 0 0.511 0.02 0 0.070 o.n' 0.002 D 0.305 D O.OlS D
51 C1'r-D-2 111.1 0.1' 11 0.303 2.1. 0.021 0.3" 0.041 0.314 0.03'
"'U Z1 rD5-C-2 11'" 0.178 0.307 0.02 V 0.031 0.25 0 0.002 D 0.305 0 0.015 D
08 2' rD8-D-2 111.1 0..1. 0.211 2.50 0.025 D 0.25 D 0.010 0.305 11 0.012
:D:r'
G)C .. 2D81a1~7 Cr1~er1. 5.0 100.0 1.0 5.0 5.0 0.2 1.0 5.0
,£~' r
1::.
..
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TABLE 2 HAZCON STABILIZATION/FIXATION PHASE II TESTING
PHYSICAL CHARACTERIZATION RESULTS
OCS TNt Per88&bi1ity Twat rr..aa/Tbav Twat
,~
OIIit Dry Poat-t.at Poat-teat Hydraulic Unit Dry
RA % COlI Hohtur. Waight oca Hobture Dry W.ight ConductiY1ty W.1ght
S~le ID Cont8Llt(') (pef) (pai) Content(') (pef) ( em/uo) (pot) to"('1 Cycl.
IIP-C-2 26.1 15.3 180 32.7 88.5 3.' :1:10-7 '..5 Ie 7
1IP-D-2 21.3 88.7 115 28.5 n.o 1.1 :1:10-1 81.5 10 2
IP-C-2 32.2 81.7 215 3t.8 83.8 1.4 :1:10-1 '1.7 75 1
IP-D-2 38.4. 81.1 75 42.8 82.4 3.7 :1:10-1 71.5 51 1
CP'1'-AZ-2 31.5 76.8 14 t5.7 71.3 3.8 :1:10-1 75.3 12 2
CPT-C-2 44.0 57.1 1 60.8 n.t t.t dO-5 U.2 100 1
CPT-D-2 37.1 70.5 10 48.1 73.7 2.5 :1:10-1 n.1 52 3
P'DS-C-2 21.2 80.8 1" 39.3 82.1 2.8 :1:10-1 ".2 n 3
1'DS-D-2 30.0 85.4 127 33.2. '0.7 1.0 :1:10-1 14.5 70 2
,
pet - poune1a per oubic foot
pai - pouncSa per &quare inoh
TABLE 3 OPTIMUM CEMENT~BASED STABILIZATION/FIXATION
TREATMENT FORMULATIONS
Hydraulic
Flue Dust Formulation Removes EP use Conductivity
Type Number Toxicity >5Opsi
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MSE Stabilization/Fixation Technology Description
Cement-based stabilization/fixation treatment involves mixing
excavated flue dust material with a combination of PC, HL, and water.
As described for the testing conducted by HAZCON and Dames and Moore,
contaminants are chemically bound and microencapsulated within the
cement crystalline matrix.
(,
Additional testing of cement-based treatment was required to
confirm treatment effectiveness of previously tested stabilization/-
fixation formulation with locally available materials and without the
use of proprietary chemical additives. Additional stabilization/-
fixation tests were conducted from February 26 through June 1990 by
MSE, Inc. in Butte, Montana. Stabilization/fixation formulations were
evaluated for the various flue dust piles: BP, IP, CPT, and FDS.
Optimum formulations were developed by MSE based on the ability of
the sample to meet TCLP and EP Toxicity criteria. Formulations that
meet these criteria are given in Table 4. Addition of un screened slag
showed variable success in increasing the UCS of the treated flue dust
and, as a result, the slag was screened to remove the -200 mesh fines
present in the material. Results of TCLP analyses for the optimum
blends are given, with qualifiers, in Table 5, and were obtained using
CLP documentation and protocol. These data are intended for use as
enforcement quality data. Physical testing which included UCS,
hydraulic conductivity, and freeze/thaw tests were also performed on
the optimum formulations. Physical results for these formulations are
provided in Table 6.
Two long-term leach tests were performed on the optimum
formulations. The multiple extraction procedure (MEP) used a sulfuric
and nitric acid leach extracted according to the EP Toxicity method.
The test is intended to simulate leaching conditions the treated
materials would undergo from repetitive acid rain precipitation.
Similarly, the American Nuclear Society (ANS) test method 16.1 is a
long-term leach in which the treated material is suspended in
distilled, deionized (01) water. The water is replaced at specified
intervals, and is filtered and analyzed for dissolved metals.
Results of the MEP and ANS 16.1 tests are given in Tables 7 and 8,
respectively. Both tests were performed using CLP documentation and
protocol, and are intended to be used as enforcement quality data. In
addition to analyzing for the eight RCRA metals in the ANS stability
testing, copper was analyzed to determine if it would leach from the
stabilized/fixed flue dust. Results indicate copper concentrat~o~s 01
up to 156 mg/l, although most extractions contained a copper
concentration below the detection limit.
2
-------
.TABLE 4
optimum stabilization/Fixation Formulations
Flue Dust Type Portland Cement Hydrated Lime Screened Slag
(to) (%) (%)
Iron Ponds 25 0 27
Bradley Ponds 20 0 26
Flue Dust 20 20 30
Storage
Coal Pile 20 20 30
Tracks
TABLE 5
Enforcement Quality TCLP and EP Toxicity Results
. Optimum stabilization/Fixation Formulations
AIW)'\c CtP Sample CLP Sample CtP S&mple CLP S&mple TCLP Criltna
!p. TCtP SP-TCLP fDS- TCLP CPT-TCLP
AnaUc 0.67 1.28 0.88 O.IOU 5.0
BarR.a 0.40 3.18 0.214 0.22 100.0
CadaUum 0.005 U 0.005 U 0.005 U 0.005 U 1.0
Chromium 0.021 U 0.008 U 0.011 0.008 U 5.0
Lad 0.069 U 0.069 U 0.069 U 0.069 U 5.0
Mcn:ury O. 00J4 0.008 0.009 0.002 U 0.2
Sc k aium 0.12 U O.IS 0.16 0.26 1.0
Saver O.OIOU 0.096 U O.OIOU 0.096 U 5.0
TCLP Toxicity (mg/l)
Sample Type Bulk Density Hydraulic Conductivity 28-day USC
(lb/ ft3) (em/s) .. (psi).
I
Iron Ponds 92.2 4.7 X 10.5 34.7
Bradley Ponds 94.2 2.9 X 10~ 38.9
Flue Dust Storage 86.6 2.3 X 10'" 59.6
Coal Pile Tracks 81.0 1.1 X 10.5 52.9
Optimum
TABLE 6
Physical Test Results
stabilization/Fixation Formulations
-------
-\
TABLE 7
.....
< Extraction
80urce Nuaber "rllnl0 Barlu8 Cad.h. Cllrc.lu8 L.ad "ercury 8ehnlu8 8Hver
8radl.~ Pond. 1 0.887 .10108 0.477 0.015 U 0.030 U 0.005 0.002 U 0.121 0.020 U
(SP-IIE .1) JCD20081S8
2 0.824 .1040 0.124 0.003 U 0.000 U 0.018 0.002 U 0.018 0.004 U
.ICOU18ea
3 0.058 .1051 0.048 0.003 U 0.000 U 0.020 0.002 U 0.011 0.004 U
.JC0102808
4 0.888 0.047 0.003 U 0.000 U 0.013 .JC 0.002 U 0.017 ..1840 0.004 U
5 0.862 0.049 0.003 U 0.006 U 0.008 JC 0.002 U 0.018 .1846 0.004 U
6 1.03 0.041 0.003 U 0.006 U 0.005 .ICO 0.002 U 0.023 .1848 0.004 U
1 0.888 0.032 0.003 U 0.006 U 0.001 U 0.002 U 0.018 0.004 U
.1045846 0.004 U
8 1.12 0.038 0 . 003 U 0.006 U 0.002 .10 0.002 0.018 .1840 0.004 U
WD200 j
9 1.46 0.042 0.003 U 0.006 U 0.001 .10 0.002 U 0.018 .1818 0 . 004 U
10 0.622 .1051 0.041 0.003 U 0.008 U 0.001 .10 0.002 U 0.022 .1816
Iron Pond. 1 0.182 ..10108 0.472 0.015 U 0.033 0.006 0.002 U 0.005 0.020 U
(IP-II£P.1) JCD20OS1S8
2 0.344 .10108 0.126 0.003 U 0.010 0.010 0.002 U 0.025 0.004 U
JCOU18ea .1110. Gg41
3 0.343 ..IDS1 0.000 0.003 U 0.006 U 0.014 0.002 U 0.044 0.004 U
JC0102808
4 0.300 0.005 0.003 U 0.006 U 0.008 JC 0.002 U 0.024 0.004 U
.J846UO.Gg3
5 0.412 0.050 0.003 U 0.008 U 0.008 ..IC 0.002 U 0.018 .1846 0.004 U
8 0.434 0.037 0.003 U 0.006 U 0.003 JCO 0.002 U 0.024 ..1848 0.004 U
7 0.482 0.025 0.003 U 0.008 U 0.001 0.002 U 0.018 0.004 U
J045S4C1UO. 883
8 0.700 0.024 0.003 U 0.006 U 0.002 ..10 0.002 0.020..1840 0.004 U
WD200
8 0.108 0.023 0.003 U 0.008 U 0.001 U 0.002 U 0.004 U
10 0.734 .1051 0.022 0.003 U 0.008 U 0.003 JQ 0.002 U 0.032 .1818 0.004 U
: 0.030 .1818
TCLP ToXioity 5.0 100 1.0 5.0 5.0 0.20 1.0 5.0
Crit.rh
ENFORCEMENT QUALITY HULTIPLE EXTRACTION PROCEDURE RESULTS TREATED FLUE
- OPTIHUH STABILIZATION/FIXATION FORHOLATIONS (mg/l)
OC REPORT NO. 12812
DUST
-------
louro. Extraction
Nuaber Ar..nio Bariu. Cad.lu. Chrodu8 lead Mercury 8elenlu. Silver
Flu. Oliit 1 0.824 .10108 0.333 0.015 U 0.030 U 0.001 0.002 U 0.227 0.020 U
8tonga WCD2oo808G
(FDS.MEP.1) 2 0.808 JD4\j 0.001 0.002 U 0.174 0 . 004 U
0.082 0.004 O.OOD
WCD111808G
3 1.02 JDS1 0.037 0.003 U 0.006 U 0.002 0.002 U 0.154 O.OO~ ua'.D
JC0102808G
4 - 0.291 0.030 0.003 U 0.006 U 0.001 JCO 0.002 U 0.1211 J8411 0.0011 U
5 1.41 0.023 0.003 U 0.006 U 0.001 WO 0.004 0.117 J84e! 0.004 U
6 1.~8 0.018 0.003 U 0.006 U 0.001 U 0.004 0.0711 .1846 0.004 U
7 1.77 0.013 0.003 0.006 U 0.001 U 0.002 0.075 0.004 U
.1045946
8 1.97 0.018 0.003 U 0.008 U 0.001 WO 0.006 0.0111 JS1e! 0.004 U j
II 2.47 0.014 0.003 0.0011 U 0.001 WO 0.008 0.054 JS18 0.004 U
11) 2.46.1051 0.013 0.003 U 0.006 U 0.001 WQ 0.010 0.034 J818 0.004 U
Coal P11. Traok. 1 0.030 JD10D 0.335" 0.016 U 0.030 U " 0.001 0.002 U 0.148 0.020 U
(CPT.MEP.1) WCD200S08G
2 0.041 JD40 0.0115 0.003 U 0.008 0.004 0.002 U 0.127 0.004 U
JC01118080110.
0l1li1
3 0.018 JDS1 0.120 0.003 U 0.000 U 0.003 0.002 U 0.088 0.004 U
JCD102SG8
4 0.017 0.102 0.003 U 0.006 U 0.002 JCO 0.002 U 0.073 .1846 0.004
5 0.011 0.081 0.003 U 0.006 U 0.001 we 0.002 U 0.064 .1848 0.004 U
8 0.014 0.073 0.003 U 0.008 U 0.001 WCG 0.002 U 0.050 .1848 0.004 U
7 0.013 0.084 0.003 U 0.008 U "0.001 U 0.002 U 0.035 0.004 U
8 .1045848
II
10 0.023 0.058 0.003 U 0.008 U 0.001 WO 0 . 002 JD200 0.052 .1846 0.004 U
0.020 0.053 0.003 U 0.006 U 0.001 WO 0.002 U 0.050 .1816 0.004 U
0.010 .1051 0.044. 0.003 U 0.006 U 0.001 WO 0.002 U 0.033 .1818 0.004 U
TCI.;' Todoity 5.0 100 1.0 5.0 6.0 0.20 1.0 5.0
;; .~;,1tI\,.la
"".
TABLE 1 CCONT'D)
ENYORCEHBH'J.' QUALITY HULTIPLE EXTRACTION PROCEDURE RESULTS TREATED FLUE DUST
OPTIHUK STABILIZATION/FI~TION FORMULATIONS (mg/l)
OC REPORT NO. 12812
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~)
TABLE 8
ENFORCEMENT QUALITY AMERICAN NUCLEAR SOCIETY 16.1 PROCEDURE RESULTS
OPTIMUM STABILIZATION/,IXATION FORMULATIONS (mg/l)*
Source exu8clion Anmic Barium Cadmium C1ItamiIllD Lca4 MCI'CUIY Scbium Copper Silvcr
< Time (day.)
Bradley Porub 0.08 0.097 O.PI1 0.0001 0.008 U 0.033 0.0002 U 0.012002.4 O.OOO2U 0.010
(BP.AN5-\) 0.19 0.041 0.013 0.000) 0.008 U 0.032 0.0002 U 0.009 O.OOO2U 0.010 U
I 0.081 0.034 0.0001 0.010 0.089 0.0002 0.017 0.036 0.010
1 0.094 0.001 0.0001 .0.008 0.091 0.0002 O.OIS O.OOO2U 0.010
) 0.(9) 0.026 0.0004 0.001 U 0.100 0.0002 U 0.014 O.OOO2U 0.010 JS10
JSI4S
4 0.081 0.02) 0.0002 0.001 U O.OSI 0.0002 U 0.011 O.OOO2U O.OIOU
JSI4S
5 o.em 0.021 JS3) 0.000) 0.001 U 0.076 0.0002 U 0.006 O.OOO2U O.OIOU
JS\)2
19 O.I1S 0.07) JS3) 0.0001 0.014 UBI.' 0.119 0.0002 U 0.032 0.079 O.OIOU
JS\)2
47 0.194 0.081 0.004 U 0.001 U 0.291 0.0002 U 0..021 JS60 0.156 O.ooS U
90 0.186 0.108 0.004 U 0.006 U 0.166 0.0002 U 0.011 JS60 O.OSt O.ooS U
Iron food. 0.08 0.011 0.010 0.0002 0.001 U 0.011 0.0002 U O.OOS UB2.4 O.OOO2U O.OIOU
(lP.AN5-I) 0.29 0.014 0.011 0.0001 0.008 U 0.018 0.0002 U 0.005 UBU O.OOO2U O.OIOU
1 0.020 o.ca 0.0001 0.001 O.OSI 0.0002 0.007 0.024 0.010
2 0.027 ~,)34 0.0001 0.008 0.049 0.000,2 0.006 O.OOO2U 0.010
) 0.025 0.02) 0.0002 0.008 U 0.005 0.0002 U 0.000 O.OOO2U 0.010
JSI45 UJ$10
4 0.027 0.024 0.0002 0.001 U 0.035 0.0002 U 0.005 JOIII O.OOO2U
JSI45 0.010
UJS70
S 0.024 0.020 JS3) 0.0002 0.001 U 0.029 0.0002 U 0.001 O.OOO2U
JSU2
O.OIOU
19 0.061 0.069 JSn 0.0001 0.001 U 0.116 0.0002 U 0.011 0.066
JS1J2
O.OIOU
47 0.080 0.080 0.004 U 0.006 U 0.149 0.0002 U 0.007 JS60
90 0.057 0.086 0.005 0.006 U 0.099 0.0002 U 0.004 JS60 0.1117
: O.OSO
O.OOS U
O.OOS U
*
QC Report Nos.
BP-ANS-l-l
BP-ANS-1-3
BP-ANS-1-5
BP-ANS-1-7
-------
TABLE'8 (CONT'D)
ENFORCEMENT QUALITY AMERICAN NUCLEAR SOCIETY 16.1 PROCEDURE RESULTS
OPTIMUM STABILIZATION/FIXATION FORMULATIONS (mg/l)
l!atraclioo
Source Number Ancnic Barium CacInIium Ouomium Lead Mercury Selenium Copper Silver
flue Dull 0.08 0.011 0.007 0.0001 V 0.008 II 0.002 0.0002 V 0.010 VB1.4 0.0002 II 0.010 U
seoraJ;e 0.19 0.026 0.009 0.0001 U O.CIOt V 0.008 0.0002 V O.OIS O.OOO2U 0.010 U
(t'DS-ANS-1) 1 0.082 0.026 0.0001 0.008 V 0.017 0.0002 0.027 O.OOO2U 0.010
2 0.081 0.024 0.0001 V 0.008 V 0.011 0.0002 U O.02S O.OOO2V 0.010
IMO.994
3 0.070 0.016 0.0001 0.008 U 0.012 0.0002 U 0.019 O.OOO2U 0.010 UJS70
J 1514S
4 0.071 0.011 0.0001 0.008 U 0.010 0.0002 V 0.016 O.OOO2U 0.010 VIS70
ISI4S
5 0.065 0.014 IS]] 0.0001 0.008 U 0.009 0.0002 U 0.010 O.OOO1U O.OIOU
15\32
j
19 0.296 0.06) IS]] 0.0001 U O.CIOt V 0.0)7 0.0002 U o.on 0.047 0.010 V
IMO.m
47 0.313 0.069 0.004 U 0.006 U 0.037 0.0002 U 0.0411S60 0.069 O.OOS V
90 0.)21 0.CJ15 0.004 U 0.006 U 0.046 0.0002 U 0.048 1S60 0.041 0.005 V
Co8iI'ilc Tract. 0.08 0.001 O.OOS 0.0001 0.008 0.011 0.0002 0.009 VB1.4 O.OOO1U 0.010 V
(moANS-I) 0.29 0.001 0.008 0.0001 0.008 0.011 0.0002 0.011 O.OOO2V 0.010 V
1 0.007 0.020 O.OOO! 0.008 0.053 0.0002 0.026 O.OOO1U 0.010
2 0.007 0.019 0.0001 0.008 O.04S 0.0002 0.021 O.OOO2U 0.010
3 0.006 0.014 0.0002 0.008 0.030 0.0002 0.011 O.OOO1U 0.010 UJS70
4 O.OM 0.0\3 0.0001 0.008 0.021 0.0002 0.015 O.OOO2U 0.010 VJS70
5 0.007 0.0\3 0.0001 0.008 0.023 0.0002 0.011 O.OOO2U 0.010 U
19 0078 0.054 0.0002 0.008 0.202 0.0002 .0.061 0.066 0.010U
47 r..Oy 0.060 O.OOS 0.006 0.\35 0.0002 0.077 1S60 o.on 0005 U
90 ,).01. 0.051 0.004 0.006 0.08) 0.0002 0.062 JS60 O.OJI 0.005 V
TCLP Toaicily 5.0 100 1.0 5.0 5.0 0.20 1.0 NA S.O
Criaerla :
NA Not A 111cable
pp
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CHEMFIX Technology
<~
Silicate-based stabilization/fixation involves mixing excavated
flue dust with a combination of soluble silicates, silicate setting
agents, and water. Metal ions in the flue dust either react with
soluble silicates forming metal silicates or precipitate as metal
hydroxides and are entrapped within the treated matrix structure. The
treated product is a friable soil-like material.
CHEMFIX Environmental Services (CES) conducted testing of the
CHEMFIX process for treatment of Smelter Hill flue dust. The CHEMFIX
process is a patented silicate-based stabilization/fixation technology
used to immobilize inorganic constituents within a waste matrix by
chemical and physical means. The treatment process is based on the use
of proprietary CHEMSET (trademark) poly-silicates, calcium-containing
reagents. These reactions produce a gel structure. The third involves
a combination of hydrolysis, hydration, and neutralization reactions"
occurring with the calcium reagent, flue dust and water. Through these
series of reactions, flue dust is chemically converted to a clay-like
soil material.
Three types of chemical reactions occur during treatment. The
first involves reactions between polysilicates, reaction promoters, and
metal ions present in the flue dust. These reactions produce metal
silicates. The second involves reactions between polysilicates and
calcium-containing reagents. These reactions produce a gel structure.
The third involves a combination of hydrolysis, hydration, and
neutralization reactions occurring with the calcium reagent, flue dust,
and water. Through these series of reactions, flue dust is chemically
converted to a clay-like soil material.
Silicate-based treatment testing conducted by CES was not
effective in removing the EP Toxicity characteristic from each of the
four major flue dust types. The CHEMFIX process was effective in
removing the EP Toxicity characteristic from SP material, but data
indicate that the treated material exhibits low strength. Treatment
effectiveness of the CHEMFIX process could not be confirmed for IP,
CPT, and FDS material due to inconsistent results from the testing
performed by CES.
HYDROMETALLURGICAL TESTING
Hydrometallurgical processes have been demonstrated to be
effective in extracting and selectively recovering metals from ores,
. concentrates, and other metal-bearing materials using wet chemical
processes. These processes usually involve dissolution of the metal
with subsequent recovery from solution. Treatability testing was
performed for three hydrometallurgical process technologies: (1)
Cashman Process; (2) Sulfide Precipitation; and, (3) Ambient Acid Leach
process. Result of testing the Cashman and Ambient Acid Leach process
is described below.
3
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Cashman Process Technology
The Cashman process is a pate~ted chloride acid leach process
designed to extract selected metals from arsenical flue dust while
converting arsenic trioxide to a stable ferric arsenate residue. The
theoretical objective of the Cashman process for Anaconda flue dust is
to remove metal values for recovery and resale, and to fix the
remaining toxic constituents of flue dust in a stable leach residue.
The process is conducted in an autoclave under elevated temperature and
pressure conditions, and is followed by a series of metal-recovery unit
operations to reclaim other metals present in the flue dust.
Early pilot tests of the Cash~an process (1987) on Anaconda flue
dust at Skykomish, Washington have produced residues that contained
arsenic in the form of scorodite (FeAs04 2H20) and coprecipitated
arsenic with ferric hydroxide. The residue from these early tests
passed the EPtox test for the leachability of metals. (Table 9).
However, the process conditions and the composition of the flue dust
used in the early tests may not have been representative of conditions
and compositions that would exist during full-scale treatment by the
.Cashman process.
Pilot-scale operational data ~ere needed to demonstrate that a
non-hazardous leach residue, consisting primarily of gypsum, could be
generated on a continuous basis by the Cashman process. Arsenic was
found to be present primarily in t~e form of ferric arsenate (PTI,
1990). Additional testing of the subsequent metal recovery unit
operations was needed to determine the effectiveness of these unit
operations in recovering metals in saleable forms.
The objectives of the test work were to demonstrate the
operability of the Cashman process on a continuous basis and to obtain
data concerning the chemical and physical characteristics of the
autoclave leach residue, metal precipitate products, and potential
waste streams generated. Testing involved a combination of pilot-scale
and bench-scale tests. Autoclave leaching, copper metathesis, and zinc
precipitation were the only unit operations which was tested on a
continuous basis. Feed preparation and metal recovery operations were
tested on a batch basis.
Samples of the autoclave leach residue were obtained
Toxicity analyses using CLP methodology and documentation
The CLP EP Toxicity data sets are presented in Table 10.
indicate that the leach residue generated during Campaign
EP Toxicity criteria.
for EP
protocols.
The CLP data
No.6 passed
~
In general, metal recoveries Here improved at pH values between
0.8 and 1.6. Observations indicated that mild steel and wetted
stainless steel surfaces were corroded under typical operating
conditions. The autoclave experienced localized corrosion under
certain operating conditions despite the use of titanium for
construction.
. i
4
-------
TABLE 9
MEAN EPTOX ANALYTICAL RESULTS FOR THE FLUE DUST PILOT
TEST SOLID SAMPLES
=:..==a==8:S:.....C.......:..c....caca=a........c:....==....sa:zc:...........===..C......=======.....S...
SAMPLE
TYPE
As
Cd
Cr
Pb
(ug/l)
Hg
Se
All
[[[
LIMITS 5000 1000 5000 5000 200 1000 5000
.. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .... .. .. .. .. .... .... .. .. ...... .. .. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .... .. .. .. .. .. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .. .... .... ...... .... .. .. .. .. .. .. .. .... .. .. .. .. .. ..
FLUE OUST FO-100-SERIES 250 3200 10 350 0.5 68 50
FLUE OUST FO-200-SERIES 210 50000 50 1600 0.5 216 50
F Il TER CAKE BEFORE IIASH 1.100 10000 1,227 50 1100 328 1.1 n
FILTER CAKE AFTER IIASH ,., 00 10333 51 33 150 0.2 52 ~
FilTER CAKE AFTER IIASH 2-100 171 77 20 98 0.2 23 10
f Il TER CAKE AftER IIASH 3-100 76 90 10 50 0.2 4 10
f ILT ER CAKE NO IIASH 4-200 104 165 11 50 0.2 8 10
F Il TER CAKE AFTER IIASH 4.200 50 100 10 50 0.2 8 10
========================================================================================================-
RUN-SERIES
TABLE 10
LEACH RESIDUE CLP EP TOXICITY RESULTS
EP TOXICITY (mg/l)
AnIIlytl
CLP s~ll
3'-A
CLP s~l.
3'-1
CLP s~ll
3'-C
CLP S~ll
3'-0
EP Toxici ty
Crlterl.
Arsenic
0_3
0.105
0.46
0.3
5.0
B8dua
0.008 UJI
0.008 UJB
0.008 UJB
0.01 UJ8
100
CedDlua
0.022
0.033
0.069
0.282
1.0
Chromlua
0.005 U
0.005 U
0.005 U
0:005 U
5.0
Lead
2.04 JSO
2.31 JSO
2.2 JSO
2.43 JSO
5.0
Mercury
0.002 U
0.002 U
0.002 U
0.002 U
0.20
Selenll.ll
0.027 JS62*S8
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Additional tests were designed to determine the stability and
leachability of metals, especially arsenic and cadmium, from Cashman
process residue under conditions that may simulate disposal within the
boundaries of the Anaconda Smelter National Priorities List (NPL) site.
Residues from two tests of the Cashman process, the batch-reactor test
(June 1989) and the continuous-reactor test (October 1989), were
investigated.
Figures 1 and 2 show concentrations of arsenic and cadmium in the
column filtrate as a function of pore volumes. Batch residue results
are also shown in these figures for comparative purposes. The arsenic
concentration increased in the continuous autoclave residue to
approximately 0.70 mg/l within the first 0.3 pore volumes and reached
an equilibrium of 1.0 to 1.4 mg/l between 3 and 10.3 pore volumes. The
cadmium concentration was ini~ially measure at approximately 3.0 mg/l
and fell to approximately 0.50 mg/l after 10 pore volumes passed
through the column.
The CLP data indicate the operating conditions of Campaign No.6
produced a leach residue that passed the EP Toxicity test. Results of
stability testing on the batch autoclave residue indicate the long-term
concentration of arsenic in the leachate was approximately 0.30 mg/l,
and the cadmium concentration in the leachate was less than 0.030 mg/l~
The objective of producing an autoclave leach residue that passes
the EP Toxicity test was met according to the CLP analytical results.
However, recently obtained results of TCLP analysis of two samples of
autoclave leach residue show the residue to exceed TCLP toxicity
criteria for lead, with concentrations of 7.9 mg/l and 13.8 mg/l,
respectively. In addition, the copper oxide, bismuth oxychloride,
cadmium cement, and lead sulfate precipitate products failed EP
Toxicity criteria.
Ambient Acid Leach Process Technology
The ambient acid leach process uses a sulfuric acid leaching
approach for treatment of Smelter Hill flue dust. The sulfuric acid
leach can be preceded by a water leaching step to selectively leach a
portion of the copper, cadmium, and zinc without leaching arsenic,
lead, or iron. Components of the processing scheme have been
demonstrated to be effective in separating and recovering select metals
from ores, concentrates, and other metal-bearing materials. Process-
and material-specific treatability data were required to evaluate the
effectiveness of the process in recovering copper from the flue dust
material.
The ambient acid leach process involves sulfuric acid leaching of
flue dust at ambient temperature and pressure conditions, solid/liquid
separation, filter cake washing, copper solvent extraction (SX) of the
filtrate, recovery of the extracted copper through electrowinning, and
treatment/recycle of the raffinate (barren solution) from SX.
:/
5
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(
FIGURE 1
Autoclave Residue: Batch and Continuous Comparison
Leach Test Type: Column
Analyte : Arsenic
As (ug/L)
2000
1500
1000
500
I!!I
1m .
I!!I
I!!I I!!I
I!!I
O'
o
2
4
6
8
10
12
14
16
18
. 20
Pore Volumes
o Batch Residue
I!!I Continuous Residue
~ DAMES & MOORE
Adillpled From: Aneccnda Smelter Au. Dual
CashmlWl Proceu R.,~'du.
Long- T onft St&billi)' 6tuc:Y.
P1\ 1110
-------
FIGURE 2
~~utoclavf: Residue: Batch and Continuous Comparison
Leaen TCist Type: Column. .
. Analyte : Cadmium
Cd (ug/L)
6000
5000 ;)
4000 <.
2000 j
[
1000 -
0
0 2
3000
4
6
8 10 12
Pore Volumes
14
16
18
20
-e- Batch Residue -&- Continuous Residue
~ DAMES & MOORE
Adapted From: Anaconda Smelter Flue Duat
Cashmen Prace.. Residue
Long-Term 6tabOIty Study,
Pt1, 1 gjK)
-------
A feedstock composed of a ~Righ~ed composite of the four major
flue dust types was processed by Hetcon using the above-treatment
sequence. The acid leach residue and the raffinate lime precipitate
were submitted to MSE for TCLP analyses. Results of the TCLP analyses
are given in Table 11. These tests were performed using CLP
documentation and protocol, and intended to be used as enforcement
quality data. Both the leach residue and lime precipitate failed TCLP
criteria for cadmium, and the leach residue failed for lead.
Since both solid residuals from the ambient acid leach process
failed TCLP toxicity criteria, they were composited and stabilized/-
fixed with PC, HL, and water. Twenty five percent of PC and HL were
added to produce the stabilized/fixed material. Results of TCLP
testing on this treated residue composite are given in Table 12. These
tests were performed using CLP documentation and protocol, and are
intended to be used for enforcement quality data. The treated material
passed TCLP toxicity criteria with the following results:
62 to 99 percent leachate concentration reductions were
observed for arsenic, 99.9+ percent reductions for cadmium
and 90 to 99+ percent reductions for lead.
Results of the Multiple Extraction Procedure (MEP) showed the
following:
56 to 99 percent leachate concentration reductions
observed for arsenic, 99.9+ percent reductions for
and 97 to 99+ percent reductions for lead over the
the test.
were
cadmium
life of
Results of the American Nuclear Society Leach Test (ANS-16.1) gave
the following:
95.6 to 99.9+ percent leachate concentration reductions of
the EP TOX criteria metals were observed over the 90-day test
life.
In addition, a 28 day UCS test on the stabilized/fixed leach
residue/lime precipitate composite showed a measurement of 143 psi,
meeting the EPA guideline of 50 psi.
(}
Of the seven unit operations tested on Smelter Hill flue dust
materials, only the ambient acid leach, copper recovery using solvent
extraction/electrowinning, and lime precipitation of the solvent
extraction raffinate steps appeared to be effective. Ambient water
leach, flotation, roasting, and zinc solvent extraction operations were
not effective in separating and recovering specific metals from all
flue dust materials.
6
-------
Analyte CLP Sample CLP Sample TCLP
LR-O-O PPT-O-o Criteria
Arsenic 0.46 2.68 5.0
Barium 0.010 UB128 0.003 U 100.0
Cadmium 6.06 2.05 1.0
Chromium 0.006 U 0.006 U 5.0
Lead 19.1 0.040 U 5.0
Mercury 0.0002 U 0.0008 0.2
Selenium 0.080 0.11 1.0
Silver 0.005 UJS34 0.005 UJS34 5.0
TABLE J J
Enforcement Quality TCLP Results
Untreated Acid Leach Residue and Lime Precipitate
QC Report No. COMB-O-o
TCLP Toxicity Cmq/1)
TABLE 12
Analyte CLP Sample CLP Sample TCLP
MET-25-25-1 MET-25-25-2 Criteria
Arsenic 0.42 0.44 5.0
Barium O. 62 JE12 0.60 , JE12 100.0
Cadmium 0.005 U 0.005 U 1.0
Chromium 0.036 UBIO 0.013 UBIO 5.0
Lead 0.16 UB91 0.11 UB91 5.0
Mercury 0.0002 U 0.0002 U 0.2
Selenium 0.12 U 0.12 U 1.0
~
Silver 0.01 UJS59 0.01 UJS59 5.0
Enforcement Quality TCLP Results
Stabilized/Fixed'Acid Residue and Lime Precipitate
QC Report No. HET-2S-2S-1 .
TCLP Toxicity Cmq/1)
v
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<>
ATTACHMENT 1
ARca COMMENTS
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. --
A -I
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ARCO <>
Post Office Box 1491
SUite 301, Fi~t Secunty Bank BUilding
307 East Par1l Street
Anaconda. Montana 59711
Telephone 406 563 521'
Facsimile 406 563 6269
:;tFJ,:C::'Jr~~7:; ..~ .'-
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J!_!~. 2 5 '~91
July 23, 1991
r~u"ir,,,,"; ,'~ ""-
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Mr. Charles Coleman
u.s. Environmental Protection
Region VIII, Montana Office
Federal Building
301 s. Park, Drawer 10096
Helena, Montana 59626-0096
Dear Charlie:
Agency
The EPA's Proposed plan for the remediation of the Flue
Dust Operable Unit at the Anaconda Smelter site has been
reviewed by ARCa, and we agree with EPA's analysis.
Accordingly, we will support the decision to use onsite
sOlidification/fixation.
Also, ~'e would like to add the following comments
regarding the. cri teria employed by EPA to select the
preferred alternative.
Long-term Effectiveness and Performance. Two leaching
methods were used to predict the long-term stability of
.the fixed and solidified flue dust samples. There are no
procedures which will unequivocally predict long-term
stability. However, the Multiple Extraction Procedure
(MEP) and the ANS 16.1 have been proposed by EPA in the
publication, ItEPA/624/6-89/122" as methods for
determining maximum leachate concentrations which could
occur under acidic environments. The results obtained
from such tests are thought to simulate long-term
leaching behavior.
However, since a degree of uncertainty remains, part of
EPA ' s proposed plan is containment of the treated' .
material in an enlarged repository which will (1) prevent
inward leakage of ~ fluid - acidic or not, (2) minimize
outward leakage of leachate, and (3) preserve protective
alkalinity. We submit that these precautiona~ measures
should be used for SIDY flue dust residues contaJ.ning high
levels of potentially leachable heavy metals.
~"":-'" c'."" ::'"! r:'r:-:,'!"'IV
"'FlCCO~'O
-------
,-,'
Reduction of Toxicity, Mobility, and Volume. Residues
which resulted from the treatment of flue dust by
fixation and solidification consistently passed TCLP
tests, whereas residues produced with Cashman and acid
leach technology failed. Proponents of the Cashman
technology have pointed out that most of their testwork
was conducted with EP Toxicity as the leachability
criterion and have alleged that their technique could be
modified to pass TCLP tests. However, their "Report on
TCLP Tests for Lead on Smelter Flue Dust Residues from
Anaconda, Montana...." dated Karch 13, 1991 shows that
Cashman residues' produced under closely-controlled
laboratory conditions passed the TCLP tests by very small
margins. The results were variable, and it is doubtful
that they would be readily reproducible under typical
continuous operating conditions in a plant. This
suggests at the very least that the residues may have to
be solidified and contained in an engineered containment
structure.
Short-term Effectiveness. The use of a mobile batch'
plant to solidify the flue dust would eliminate the
potential that small amounts of flue dust would
contaminate the haul roads connecting the storage piles.
Processing the dusts for metals recovery, at elevated
temperatures and pressures with corrosive reagents will
inevitably expose operating personnel to hazards of the
workplace. ,( See comments regarding Hazards and
o~erability in the next section). We believe that the
s~mple and proven methods which would be used during
fixation/solidification would eliminate such worker
hazards except for those related to rotating equipment.
Implementability. A mobile batch plant is simple to
build, operate, and move. Concrete making is probably
the most well-known of material processing technologies.
The equipment is reliable, parts are easily obtained, and
exotic construction mater1.als are not required. The
operating flexibility of a batch plant would enable ]:apid
suspension and restart of operations in response to harsh
winter conditions. More complex processing plants do not
have this flexibility; moreover, process efficiency
always suffers from shutdown and upsets. .
Mobile batch plants commonly are available for lease,
resulting in ready availability of knowledgeable plant
owners and operators. This would obviate the expensive,
time-consuming I and' potentiallY dangerous training
programs needed for operators and supervisors of complex
chemical processing plants. Quick and simple batch plant
startup promises maximum initial throughput, minimum.
total time to project completion, and minimal piloting of
the treatment process.
-------
The complexity and potentially hazardous nature of the
Cashman technology as applied to flue dust is illustrated
by the outcome of a Hazard and operating study (HazOp)
conducted for ARCO by a team of consultants in september,
1990. The subject was Bechtel's design of a Cashman
plant to treat Anaconda flue dust, and the object of the
study was to identify hazards to operators and to the
enviromr,ent, as well as operability problems which could
compromise the plant's ability to achieve and sustain
design throughput and required residue leachability. The
principal intent was to reveal safety hazards and to
develop accident scenarios, while only limited attention
was given to operability problems and economic
consequences. -A mw;m more detailed study subsequent to
further piloting would be needed to quantify the latter.
Over 600 safety-related accident scenarios were developed
and over 100 design modifications were identified which
needed correction to meet either OSHA regulations or to
comply with the operating principles of responsible plant
managers.
. For example, the design suffers from many examples of
highly potential spills of hot liquids and slurries,
generation and release of hydrogen/a1r mixtures, and the
like. There also is a significant potential for
autoclave explosions.
The HazOp study concluded with the following paragraph:
"...A1though each individual unit operation in the
process is relatively simple, the combined process is
very complex. It requires extensive recycling and
careful control of process parameters through every step
of the treatment. The process is operator-intensive,
thereby being prone to. human errors and operability
problems. Addition of interlocks to improve the safety
of the system by reducing the potential for human error
could make the system even more difficult to operate.
From an economic perspective, numerous accidents. were
identified which were not safety-related but would cause
contamination of products. It should be assumed that a
significant portion of the facility life is (would be)
spent reprocessing these contaminated products."
Cost. The operating cost uncertainties of a batch plant
are small, reflecting mainly fluctuations in cement price
and the rental rates of equipment and operators. Both
capital and operating cost estimates for the first
commercial application of a complex processing technology.
are very uncertain - even when based on very detailed
plant design, which has not yet been done for the CashInan
Process. Invariably, these estimates grow as more is
learned about a process and more detailed engineering has
been completed. Early "optimism" with regard to costs
,
-------
c.:
usually reflects failure to consider fully the
engineering obstacles which must be overcome. It is
1 Deely that satisfaction of the HazOp findings alone
could add 50 to 100 percent to the preliminary capital
cost estimate and increase operating costs signif icantly.
In summary, ARCO believes that the data provided in the
Flue Dust RI/FS accurately portray the problem and define
the remedial alternatives which are currently available.
The Comparative Analysis of Alternatives ~rovided by the
EPA clearly shows that Solidification/F1xation is the
preferred remedy, as it can be accomplished quickly using
a simple process to eliminate the problem permanently.
cc: Greg Mullen
Pam Sbar, Esq.
Bob Lawrence, Esq.
Robin Bullock
Terry McNulty
c
-------
ARca ~~
Post Office Box t491
SUite 301, First Secunty Bank Building
307 East Park Street
Anaconda. Montana 59711
Telephone 400 563 5211
Facsimile 406 563 8269
July 31, 1991
Charlie Coleman
Anaconda Project Manager
U.S. Environmental Protection
Region VIII, Montana Office
Federal Building
301 S. Park, Drawer 10096
Helena, MT 59626-0096
A -2.
VIA FAX
Agency
Re:
ARC 0 , s Comments on Anaconda
Operable Unit, Proposed Plan
Dear Mr. Coleman:
:.:.~ -;..'
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:.~.~:~'L"~:" '.:.{1:~~~
Smelter site,
Flue Dust
ARCO submits the following attachments in support of EPA's June
1991 Anaconda Smelter site, Flue Dust Operable unit Proposed Plan.
ARCO respectfully requests that EPA consider the attached comments
in selecting the final remedy for this Operable unit.
I /
, l,
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ARCO~'O
-------
-.. -... -
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-
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TO:
ROBIN BULLOCK
SUPERFuND COORDINATOR
ARCO
(406)563-8269
FROM: TERRY MCNULTY
7/31/91
RB:
SOLIDIFICATION/FIXATION OF ANACONDA 5MBLTER FLUE DUSTS
COKMENTS REGARDING CALCIUM ARSENATE, XRD, aA20P.
c~LCIUH ARSENATB AND XRD
X-ray diffractometer (XRD) scans have disclosed that the
untreated dusts already contain arsenic principally as
calcium arsenate. The calcium arsenate apparently formed
when lime and water were added to the acidic dusts which
contained arsenic trioxide and, possibly, arsenic acid. The
XRD pattern lines for pure calcium arsenate correspond well
with some of the pattern lines for the four untreated dusts
which were studied. However, some of those lines are
missing from the XRD patterns for the treated dusts.
Moreover, many new lines are generated by the treated dusts
, and some do not correspond either to patterns for untreated
dust or for common cement curing compounds such as calcium
silicate and calcium aluminum silicate. Direct comparisons
of XRD patterns for untreated and treated dusts
unfortunately are impossible to make because the analyses
were made at different times with different levels of
background correction. Furthermore, a considerable amount
of line broadening and peak attenuation accompanied
treatment - indicative of a reduced degree of crystallinity,
increased compound complexity (perhaps nonstoichiometric -
compound formation), and possibly the formation of semi-
amorphous compounds. While this makes precise comparisons
and compound identification nearly impossible, it is highly
suggestive that new and stable compounds formed.
The ANS 16.1 leachability test is, in effect, a stringent
determination of multi-component solubility in de-ionized
water. The solubility of calcium arsenate as a function ot
pH is well documented and it is 130 ppm in de-ionized water
at 25 degrees Celsius. The ANS 16.1 solubility for arsenic
and even the MEP solubility using an acidic medium are lower
by a factor of 100 to 1000 than the published solubility of
calcium arsenate.
(.
These two pieces of evidence indicate very strongly that
arsenic in treated flue dust is present as one or more
species which may contain other metals such as copper, lead,
and zinc in addition to arsenic. This is supported by one
of Dr. R.G. Robins' observations, II.. . copper, zinc, lead,
barium, and mercury may be the actual stabilizing influence
1n many disposal situations.
-------
.---~.-~. ~~. .~..~
-
. -..... ..~., - - . ;
.. ' . . - - . - . -. -
HazOp
Hazard and operability ("HazOp") assessments are becoming
commonplace in the processing industries and are policy
requirements in some corporations. A HazOp conducted on a
preliminary design provides a cost-effective way of
identifying changes which must be incorporated in the final
design. usually the final design is subjected to a second
HazOp in order to disclose problems which were missed the
first time around or were introduced during detailed
engineering. The total cost of the two HazOps on a complex
plant costing in the range of $50-100 million to build will
typicallY be $75000 to $125000, compared with an engineering
fee in the range of $4.10 million. Hence, the HazOp at any
level is a cheap "insura~ce pOlicy" and 1s a good way of
estimating the operability 'of a plant.
-------
... \..:L.. - .; 1 . : .
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TO
: Robin Bullock
superfund cooordinator
Atlantic Richfield Company
FROMs T. P. McNulty and F. N. Ramseier
T. P. McNulty and Associates, Inc.
July 31, 1991
RE
: ANACONDA FLUB DUST OPERABLB UNIT
Comments on Ju1y 23, 1991 Public Meeting in Anaconda.
The following comments are in approximate chronological
order. Some names may not be correctly spelled and most
comments have been abbreviated and editorialized; we feel,
however, that they accurately convey the spirit of the
statements which were made. Neither Joe Cashman nor Dr. L.
G. Twidwell was present. Reactions by Ramseier and McNulty
to individual comments are presented in italics after each
public comment, although neither consultant offered
observations until after the formal meetinq was closed.
Charlie Colaman (EPA) The deadline for written comments
will be the. end of July, with a ROD scheduled for the end of
September.
Ethan. Patasbnik (Artech) Requested that a Question and
Answer period precede the Comment period, but was told by
Coleman that the June meeting provided the opportunity for
questions and that discussion would be encouraged after the
formal hearing. .
Kelvin A. stokke (Citizen) He was supportive of the
Solidification and Fixation proposal and commented that
Anaconda's Research Department worKed on flue dusts for 15
years without ever findin9 a successful solution. This work
included an acid leaching process followed by solvent
extraction and electrowinning. He cited the Arbiter Plant
as an example of the difficulty of commercializing new
technology. He expressed concern regarding the hauling of
fixed material to the repository and the movement of
vehicles on the material after placement. He suggested
casting concrete blocks and stacking them in the repository.
Mel misunderstood the manner in which the tlue dusts will be
mixed with lime, portland cement, and water, but his other
comments were absolhtely correct. .
Ed Huestis (citiz~n) He observed that sulfurous and
sulfuric. acids would have formed when water was added to the
flue dust (and reacted with the sulfur dioxide contained in
the dust) and wondered if ARCO's contractors had taken this
into account. The flue dusts were all limed before being
placed in tbe existing temporary impoundments. Then,
fixation will bring the tinal alkalinity to about pH 12.
Allot the original sullurous/sulfuric acid will have been
converted to gypsum.
. -- ,... .:' ---.-.T ,'T"T:" c:.:. T~('.
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. ... .. -.
. . -
-- . - -
- .. - .
Ethan Patashnik (Artech) He said that reviewing the
proposal was a tough job, that he could understand how many
laymen simply do not understand it, but that Artech's staff
of research people had studied it in great detail. He
pointed out that ARCO had attempted to obtain a license from
Artech and that this vindicated the process. He said that
Dr. Robins 1s in favor of metals recovery and that we should
not leave problems for our grandchildren. Earthquakes could
cause the repository to fail. The residue will be unstable
because calcium arsenate is unstable. The preferred
fixation method in industry 1s oxidation to form ferric
arsenate. Dr. Robins ravors metal recovery because he hates
to "waste" resources. The engineering profession is skilled
in designing structures to withstand earthquakes. As
discussed in a separate writeup, the arsenic probably forms
a very complex and very insoluble compound, not simply
calcium arsenate. In ~act, because of the liming done
during the early 19805, the arsenic in the eXisting dusts
has already been converted to calcium arsenate. SOlidifica-
tion and fixation in the presence of copper, lead, etc.
probably converts the original calcium arsenate to other
compounds. In4ustry 40es not have a preferred procedure for
treating arsenical solids.
Con Hales (Citizen) He fully supports Solidification and
Fixation because it meets all criteria. The citizens do not
~an~ a test site in Anaconda. He does not want his children
working in a plant which treats ar~enic and beryllium.
"Please allow us some control over what happens in our
backyard. II
Loe Snow (citizen) offsite disposal is best because we
cannot afford to have hazardous materials at the headwaters
of a large river. No containment is good enough.
Richard xunter (Artech) He explained that he was a standin
for Dr. RObins. He said that. long..term stability of the
residue is in question because oopper will leach. Metal
recovery is the preferred route. He also noted that Robins
is not necessarilY in favor of the Cashnan Proc~ss.
Dr. Ka~el Tuchsberer (Citizen) she agrees with the EPA rec-
ommendation, but believes that the toxicity of arsenio has
been qrossly exaggerated.
sill Bedal (Artech) He feels that the ANS 16.1 procedure is
a simple one, but that there were honest errors and. .
omissions on the part of the contractor who performed them.
Diffusion coefficients were not calculated. Although not
important, recommended surface area/liquid ratios ~ere not
followed. He finds it "appalling" that EPA did not review
the conclusions more carefully. He calculates that Pb and
Cd will be stable for millions of years, but that
significant arsenic will leach from the Iron pond dust in 57
years, from the Brcdley Pond dust in 11 years, from the Coal
pile Tracks dust in 1000 years, and from the Flue Dust
Storage dust in 135 years. This issue will be dealt with in
a separate writeup. Hr. Badel is incorrect.
"
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- 0 -- 0 ... 0 .. - - ...
. 0-"" 0 ... .\... 0.'
Nicki Leiss (citizen) She supports the EPA recommendation
because it will solve the problem quickly.
Sandy stash (ARCO) The S/F study was flawless and ARCO is
ready and willing to proceed.
Haggie snow (Citizen) How much would it cost to haul the
dust offsite and diispose of it? sandy stash answered that
the range would be $60-70 ~illion.
.....
The formal meeting was closed by Charlie Coleman and it was
re-opened for informal discussion.
*....
Dr. Kabel Tuchsherer
where would it go?
Charlie Coleman There are few such places and it would be
better for all concerned to leave the dust in Montana.
sill Badal Was the HazOp a part of the RI/FS? Was it used
for AAL? .
Sandy stasb HazOps are a part of the ARCO decision making
process.
Bill 8e4a1 It would be better to conduct a HazOp on the
final design.
sandy stash There will be one for SIP.
Ethan Patashnik The Artech consultant says that, as a
result of-the Ha~Op, the cost will be less, not more. The
ANS 16.1 data cannot be supported and are not useable.
Terry KcNulty In fact, the HazOp indicated that the Bechtel
estimate was low by a factor of 50% or more. He explained
that the ANS 16.1 was developed for radionuclides and that
the precautionary statement at the end of the procedure
(about analyzing filtered solids if filtration is employed)
has to do specifically with soluble radionuclides which
undergo decay to insoluble daughter products. Following the
procedure blindly for heavy metals will introduce errors.
Earlier- comments about instability of calcium arsenate are
not appropriate because the fixation product formed from.
treatment of multicomponent flue dusts appears to be a very
complex arsenate with much lower solubility than any of the
simple arsenates produced from pure systems.
Charlie coleman proper QA/QC was followed during ANS 16.1
tests. Usability may indeed be an issue and it is under
review, but he does not expect a problem. There 1s no --
definitive long-term stability test. The RD/RA will refine
the SIF method and will derive optimumforrnulas.
24 Huestis Did Arco look at physical methods of
concentration, e.g. a wind tunnel which would separate
particles by specific gravity?
~iok Ramseier Yes, many techniques were investigated,
including gravity and volatilization.
Ed HUestis The government should sponsor a 100-year field
laboratory in the Anaconda area to study waste treatment and
If the material were moved o££site,
-------
~ ..... -. -. ''''-- .....' ~-
-
. -' .11. I .....,: - - .
". .,..
.. - - - . -. -
~etal recovery. He noted, however, that it would never make
money, just provide jobs.
charlie coleman Protection of the environment and human
health is most important, not recovery of metals.
Leo Snow Is there now a problem with release of flue dusts
into the environment?
sandy stasb an4 Charlie Coleman A surfactant is applied
which minimizes the problem.
l)
-------
A -3
ARca ~>
Post Qftoee Box 1491
SUite 301, Fi~t Secunty Bank BUIlding
307 East Pa(1( Street
Anaconda. Montana 59711
Telephone 406 563 5211
FaCSimile 406 563 8269
CERTIFIED - .RETURN RECEIPT REQUESTED
July 31, 1991
c....
Mr. Charles coleman
Anaconda project Manager
U.S. Environmental Protection
Region VIII, Montana Office
Federal Building
301 S. Park, Drawer 10096
Helena, MT 59626-0096
Agency
Mr. Gregory Mullen
Sol id & Hazardous Waste
Montana State Department of
Health & Environmental
Sciences
Cogswell Building
Helena, MT 59620
Re:
~CO's Comments on Anaconda Smelter Site, Flue Dust
Operable unit, proposed Plan
Dear Mr. Coleman and Mr. Mullen:
ARCO submits the following comments on EPA' s June 1991
Anaconda Smelter site, Flue Dust Operable unit Proposed Plan.
I.
ANS 16.1 LEACH TEST
The ANS 16.1 Procedure was developed by the American Nuclear
society as a means for predicting the long-term leachability of
radioactive materials from .solid repositories under adverse
exposure conditions as a function of time. The ANs 16.1 method has
been extended to test other materials ".. .so that it (ANS 16.1)
more nearly represents anticipated conditions under which a
solidified waste form may be stored, transported or disposed. "
(Chemical Fixation and Solidification of Hazardous Wastes, Chapter
14). The ANs 16.1 Procedure applied to nonradioactive heavy metal-
bearing materials may produce a leachate wherein fine particulates
are suspended. If so , these will be flue dust constituents which
have not dissolved, but are simply too small to settle out during
the. time allowed in the Procedure. These particulates should be
removed from the leachate and not assayed because they represent
heavy metal sources which have not leached. Inclusion in the total
assay would overstate the dissolved heavy metal concentration.
since the objective of the test was to determine the concentration
of metals which may become mobile during the leaching process, and
not to determine the metals concentrations in the sediment, a
decision was made to filter the leachate. This modification'more
accurately represents the disposal conditions which would exist for
the stabilized Anaconda Flue Dust. This decision was also
consistent with previous ANS 16.1 tests performed for long-term
stabilization determination in other EPA Regions (i.e. EPA Region
IV).
The ANS 16.1 test produces a leachate which is sampled and replaced
at. designated intervals. Analysis of the samples for the
element(s) of interest is used to calculate effective diffusivity
- . ..... -..-.
ARCOD~~O
-------
using a standard equation. The leachability index is then
calculated as the negative logarithm of the average effective
diffusivity. The leachability index is defined as a parameter that
characterizes the resistance of the solid waste to leaching of
constituents. scientific literature does not describe it as a
method to estimate when an element has been totally leached.
Wi thin the attached
information:
information you
will
find
the
following
1. The mean time interval (American National standards)
2. Dissolved metal concentrations (mg/l)
3. Delta T (Change in time from sanpling to sampling)
4. Metal concentrations (converted to mg/kg from 11)
. .
5. Total concentrations from raw flue dust
6. The effective diffusivity for each sampling
7. The leachability index
The EPA uses the leachability index as an indication of the.
diffusion rates of an element as it is leached from a solid waste.
A leachability index of 5 to 10 indicates rapid diffusion, whereas
an index of 10 to 15 suggests very slow diffusion (stabilization
/Solidification of CERCLA and RCRA Wastes, EPA/625/6-89/022). The
Anaconda flue dust leachability. index for arsenic, as reported in
the attached documentation, ranges from 10.6 to 14.3, depending on
the sample location, thus indicating a very slow di.ffusion rate of
arsenic, lead and cadmium from the residue.
These comments set. forth above are intended to supplement our
previous communications and correspondence with the Agency
pertaining to the Flue Dust Operable Unit. .
ARCO respectfully requests that EPA carefully consider the
additional information provided in selecting the final remedy for
this 0 erable Unit.
"
-------
ARCO . ANSI LONG TERM LEACHING STUDY
. LEACHABILITY INDEX
MEAN TI"E INTERVAL (FOR OIFFUSIVITT CALC.)
INTII
INT'2
INTl3
INTl4
INTIS
INTl6
INTI7
INTl8
INTl9
I NTII 0
..c...:.....zacc====.......cs......ac..c..............a..........c........................
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
7200 25200 86400 172800 259200 345600 432000 1573200 3978000 7885560
tll 1/2 tl2 1/2 tl3 1/2 tl4 1/2 tiS 1/2 tl6 1/2 tl7 1/2 tl8 1/2 tl9 1/2 tll0 1/2
==========================..===============ac:..======_.=cec====._ca:.a.:=.:=.....:=a.a.:-
84.85 158.75 293.94 415.69 509.12 587.88 657 .27 1254.27 1994.49 2808.12
84.85 158.75 293.94 415.69 509.12 587.88 657.27 1254.27 1994.49 2808.12
84.85 158.75 293.94 415.69 509.12 587.88 657.27 1254.27 1994.49 2808.12
84.85 158.75 293.94 415.69 509 . 12 587.88 657.27 1254.27 1994.49 2808.12
84.85 158.75 293.94 415.69 509.12 587.88 657 .27 1254.27 1994.49 2808.12
84.85 158.75 293.94 415.69 509.12 587.88 657.27 1254.27 1994.49 2808.12
XTI1 X Tl2 X T'3 X Tl4 X TIS X Tl6 X T'7 X Tl8 X Tl9 X 11 iO
-==========-======-===-=========&====-=====_====2===_==..a=:c...:.-:..==::::=.....:==:=...
1800.0
1800.0
1800.0
1800.0
1800.0
1800.0
14835.0
14835.0
14835.0
14835.0
14835.0
14835.0
51230.7 125894.0 213818.0 300849.2 387596.3913496.1
51230.7 125894.0 213818.0 300849.2 387596.3 913496.1
51230.7 125894.0 213818.0 300849.2 387596.3913496.1
51230.7 125894.0 213818.0 300849.2 387596.3 913496.1
51230.7 125894.0 213818.0 300849.2 387596.3 913496.1
51230.7 125894.0 213818.0 300849.2 387596.3 913496.1
2638619
2638619
2638619
2638619
2638619
2638619
5766281
5766281
5766281
5766281
5766281
5766281
Concentrations in mg/l .Sampling'l (n-l)
SAMP vr SAMPLE' :
c_.a..........-.==.-.:=...:===.-:...::a.:::-.::.......=...=...=...c.=.=..====.....=...........c.c......ac~c.
As
8a
Cd
Cr
Cu
Pb
Kg
Se
Ag
133.0 X4820 0.097 0.017 0.0001 0.008 0.017 0.033 0.0002 0.012 0.010
115.7 X4821 0.018 0.010 O. 0003 0.008 0.017 0.011 0.0002 0.005 0.010
129.8 X4822 0.018 0.007 0.0001 0.008 0.017 0.003 0.0002 0.010 0.010
135.2 X4823 0.010 0.008 0.0001 0.008 0.017 0.002 0.0002 0.012 0.010
114.6 X4824 0.001 0.005 0.0001 0.008 0.017 0.011 0.0002 0.009 0.)10
125.7 Ex. 8lank 0.001 0.005 0.0001 0.008 0.017 0.001 0.0002 0.001 0.010
Sampling '2 (n-2) Concentrations In mg/l
SAMP VI SAMPLE' : As 8a Cd Cr Cu Pb Kg Se Ag
......................=c=c~.....a...==.==..a...s.....c[[[
133.0 X4820 0.041 0.013 O. 0003 0.008 0.017 0.032 0.0002 0.009 0.010
115.7 X4821 0.014 0.012 0.0001 0.008 0.017 0.018 0.0002 0.005 0.010
129.8 X4822 0.026 0.009 0.0001 0.008 0.017 0.008 0.0002 0.015 0.010
135.2 X4823 0.020 0.010 0.0001 0.008 0.017 0.003 0.0002 0.016 0.PI0
114.6 X4824 0.001 0.008 0.0001 0.008 0.017 0.018 0.0002 0.012 0.010
125.7 Ex. Blank 0.001 0.005 0.0001 0.008 0.017 0.001 0.0002 0.001 0.010
Sampling '3 (n-3) Co~centrations in mg/L
SAMP \IT SAMPLE': As Sa Cd Cr Cu fib H~ Se Ag
=.D==========c======================~===============~=============================~~~~===============::~====
133.0 X4820 0.088 0.035 0.0001 0.010 0.036 o.eag 0.0002 0.017 0.010
115.7 X4821 0.029 0.028 0.0001 0.008 0.024 0.051 0.0002 0.007 0.010
129.8 X4822 0.082 0.026 0.0001 0.008 0.017' 0.017 0.0002 0.027 0.010
135.2 1<\823 0.066 0.022 0.0001 0.008 0.073 0.010 0.0002 0.028 0.010
114.6 X4824 0.007 0.020 0.0001 0.008 0.017 0.053 0.0002 0.026 0.010
-------
Sampling 14 (n-4)
SkMP WT SAMPLE':
Concentrations In mg/L
aE8........~....a=..z===..Z&.=........................c[[[
As
Ba
Cd
Cr
Cu
Pb
H9
5e
Ag
133.0 X4820 0.09S 0.032 0.0001 O.OOB 0.011 0.091 0.0002 O.OIS 0.010
II 5 . 1 X4821 0.027 0.034 0.0001 0.008 0.011 0.049 0.0002 0.006 0.010
129.8 X4822 0.088 0.024 0.0001 0.008 0.017 0.018 0.0002 0.025 0.010
135.2 X4823 0.068 0.022 0 . 000 1 0.008 0.017 0.010 0.0002 0.026 0.010
114.6 X4824 0.007 0.019 0.0001 0.008 0.017 0.045 0.0002 0.022 0.010
125.7 Ex. 8lank. 0.001 0.005 0.0001 0.008 0.017 0.001 0.0002 0.001 0.010
Sampling 15 (na5) Concentrations In mg/L
SAXP WT SAMPLE': As 8a Cd Cr Cu Pb Hg 5e Ag
&C==.=D.&..C.==.=z=:c=&=.==.===...==.-=z.=~=.c.=.#==.&......=.....cc...................a.......=====S=......
133.0 X4820 0.169 0.026 0.0004 0.008 0.017 0.100 0.0002 0.014 0.010
115.7 X4821 0.025 0.023 0.0002 0.008 0.011 0.035 0.0002 0.003 0.010
129.8 X4822 0.070 0.016 0.0001 0.008 0.011 0.012 0.0002 0.019 0.010
135.2 X4823 0.055 0.021 0.0001 0.008 0.011 0.007 0.0002 O.OIB 0.010
114.6 X4824 0.006 0.014 0.0002 0.008 0.011 0.030 0.0002 0.018 0.010
125.7 Ex. 8lank. 0.001 0.005 0.0001 0.008 0.011 0.001 0.0002 0.001 0.010
5~~pling 16 (n=6)
Concentrations in mg/L
SAXP WT SAMPLE':
a.========:-.==:===:==._.=a.:==::=::.:=-==.c=:====.a.:===8=.-.....=_....a.=......=............_====......2.8
As
Ba
Cd
Cr
Cu
Pb
Hg
5e
Ag
133.0 X4820 0.082 0.023 0.0002 0.008 0.011 0.051 0.0002 0.011 0.010
115.1 X4821 0.027 0.024 0.0002 0.008 0.017 0.035 0.0002 0.005 0.010
129.8 X4822 0.071 0.018 0.0001 0.008 0.011 0.010 0.0002 0.016 0.010
135.2 X4823 0.053 0.018 0.0003 0.008 0.017 0.006 0.0002 0.013 0.010
114.6 X4824 0.005 0.013 0.0001 0.008 0.017 0.022 0.0002 0.015 0.010
125.7 Ex. Blank. 0.001 0.005 0.0001 0.008 0.011 0.001 O. 0002 0.001 0.010
Sampling 17 (ns7) Concentrations in mg/L
5AMP WT SfJlPLEI: As Ba Cd Cr Cu Pb Hg 5e Ag
-=:====::=========:================.===========:=====:=.===.c=#==c==:.=zc====c====c=ac==~==c=.c===a=====.s..
133.0 X4820 0.017 0.021 0.0003 0.008 0.017 0.076 0.0002 0.006 0.010
115.7 X4821 0.024 0.020 0.0002 0.008 0.011 0.029 0.0002 0.001 0.010
129.8 X4822 0.065 0.014 0.0001 0.008 0.017 0.009 0.0002 0.010 0.010
135.2 X4823 0.049 0.016 0.0001 0.008 0.017 0.006 0.0002 0.011 0.010
114.6 X4824 0.007 0.013 0.0001 0.008 0.017 0.023 0.0002 0.011 0.010
125.7 Ex. 8lank. 0.001 0.005 0.0001 0.008 0.011 0.001 0:0002 0.001 0.010
Sampling 18 (na8) Concentrat1ons in mg/L
SAMP WT 5AXPlE': As Sa Cd Cr Cu Pb Hg 5e Ag
.c========aca===as==aca==a=====..=..=:=_==a===..sc.:....=.=..=......===...==.=~c....==.=====.==...===.=..c=.
133.0 X4820 0.115 0.073 0.0001 0.014 0.080 0.219 0.0002 0.032 0.010
115.1 X4821 0.068 0.069 0.0001 0.008 0.066 0.136 0.0002 0.011 0.010
129.8 U822 0.296 0.063 0.0001 0.008 0.047 0.037 0.0002 0.058 0.010
135.2 X4823 0.226 0.057 0.0001 0.008 0.045 0.022 0.0002 0.062 0.010
114.6 X4824 0.078 0.054 0.0002 0.008 0.066 0.202 0.0002 0.061 0.010
125.7 Ex. Blank 0.001 0.005 0.0010 0.008 0.017 0.001 0 . 0002 0.001 0.010
Sampling 19 (n=9) Concentrat1ons In mg/L
SAMP \IT 5AXPLE' : As Sa Cd Cr Cu Pb Hg Se Ag
:==========_._========-===========z=======a=========a============....a=c...ua....=...==..C..==...===..U.....
133.0 X4820 0.194 0.089 0.0041 0.007 0.156 0.291 0.0002 0.028 0.005
115.7 X4821 0.080 0.080 0.0041 0.006 0.107 0.149 0.0002 0.007 0.005
129.6 X4622 0.323 0.069 0.0041 0.006 0.068 0.037 0.0002 0.041 0.005
135.2 X~8,3 0.245 0 074 0.0041 0.006 0.050 0.025 0.0002 : . ~ (: 5 0.005
114.6X4824 0.034 0.060 '" I"'Il'\tA 0.006 0.053 0.135 0.0002 ').:::;/ 0.005
V.V\,/,J"
-------
Samp1ing '10 (n.IO) ConcentratIons In mg/l
SAMP ',IT SAJ4PL[I: As Ba Cd Cr Cu Pb Hg Se Ag
[[[
133.0 X4820 0.186 0.108 0.0041 0.006 0.058 0.266 0.0002 0.011 0.005
115.7 X4821 0.057 0.086 0.0053 0.006 0.050 0.099 0.0002 0.004 0.005
129.8 X4822 0.328 0.075 0.0041 0.006 0.042 0.046 0.0002 0.048 0.005
135.2 X4823 0.224 0.073 0.0041 0.006 0.040 0.017 0.0002 0.034 0.008
-------
ARCO - ANSI LONG TERM lEACHING STUDY
- LEACHABILITY INDEX
EFFECTIVE DIFFUSIVITY (DELTA T)
&.......=..........#...0=...............:=:...:=.28:8=_.ac.........-==....=-==..........=-
INTI1
INTIZ
INTI3
I"TI4
INTIS
INTI6
INTI7
INTl8
INTI9
INTI10
\
. I
7200 18000 61200 86400 86400 86400 86400 1141200 2404800 3907560
7200 18000 61200 86400 86400 86400 86400 1141200 2404800 3907560
7200 18000 61200 86400 86400 86400 86400 1141200 2404800 3907560
7200 18000 61200 86400 86400 86400 86400 .1141200 2404800 3907560
7200 18000 61200 86400 86400 86400 86400 1141200 2404800 3907560
7200 18000 61200 86400 86400 86400 86400 1141200 2404800 3907560
ELEMENTAL CONCENTRATIONS (FROM LEACH EXPERIMENT) An
Concentrations in mg/kg -Sampling II (n-l)
SAMPLEI: As 8a Cd Cr Cu Pb Hg Se Ag
.....=========:===========:==.==.=.=.=============~===.==..=...~==c.===&==========.......=c====....
X4820 0.073 0.012 0.0001 0.006 0.013 0.025 0.0001 0.009 0.007
X4821 0.016 0.008 O. 0002 0.007 0.015 0.010 0.0001 0.004 0.008
X4822 0.014 0.005 O. 0000 0.006 0.013 0.002 0.0001 0.008 0.007
X4823 0.007 0.006 0.0001 0.006 0.013 0.001 0.0001' 0.009 0.007
X4824 0.001 0.005 0.0001 0.007 0.015 0.010 0.0001 0.008 0.008
Ex. Blank 0.001 0.004 0.0000 0.006 0.014 0.001 0.0001 0.001 0.008
Sampling 12 (na2)
Concentrations in mg/kg
SAMPLEI: .
....&0===========..=====..=...._======-======..====..===ca......=:=:::=========.......=:===:==:==..
As
8a
Cd
Cr
Cu
Pb
Hg
S.
Ag
X4820 0.031 0.010 0.0002 0.006 0.013 0.024 0.0001 0.007 0.007
X4821 0.012 0.010 0.0001 0.007 0.015 0.016 0.0001 0.004 0.008
X4822 0.020 0.007 0.0001 0.OU6 0.013 0.006 0.0001 0.011 0.007
X4823 0.015 0.008 0.0000 0.006 0.013 0.002 0.0001 0.012 0.007
X4824 0.001 0.007 0.0001 0.007 0.015 0.016 0.0001 0.011 0.008
Ex. Blank 0.001 0.004 0.0000 0.006 0.014 0.001 0.0001 0.001 0.008
Sampling 13 (n-3) Concentrations in mg/kg
SAMPLEI: As Ba Cd Cr Cu Pb Hg Se Ag
....====_=ac:==s==c===a....=.......=ea..=..........==..c.....c.a.:-::::=::........:.:-..-.==.:::::.
X4820 0.066 0.026 0.0001 0.007 0.027 0.067 0.0002 0.013 0.007
X4821 0.025 0.025 0.0001 0.007 0.021 0.044 0.0002 0.006 0.008
X4822 0.063 0.020 0.0001 'G. 006 0.013 0.013 0.0002 0.021 0.007
X4823 0.048 0.016 0.0001 0.006 0.054 0.008 0.0001 0.021 0.007
X4824 0.006 0.017 0.0001 0.007 0.015 0.047 0.0002 0.023 0.008
Ex. Blank 0.001 0.004 0.0001 0.006 0.014 0.001 0.0002 0.001 0.008
Sampling 14 (n-4) Concentrations In mg/kg
SAMPLE': As Sa Cd Cr Cu Pb Hg S. Ag
...............::.-......................................=a...~.:.....=c=a............=====.=C=.=..
X4820 0.071 0.024 0.0001 0.006 0.013 0.068 0.0002 0.011 0.007
X4821 0.023 0.030 0.0001 0.007 0.015 0.043 0.0002 0.005 0.008
X4822 0.068 0.019 0.0001 0.006 0.013 0.014 0.0002 0.019 0.007
X4823 0.050 0.016 0.0001 0.006 0.013 0.007 0:0001 0.019 0.001
X4824 0.006 0,017 0.0:01 0.007 0.C15 0.040 ~.0002 0.019 O. ::5
Ex. Blank 0.001 0.004 O.O~~l 0.006 0.C14 O.oOl ~.C002 0.001 n .....",
11...0
Sampling 15 (n-5) Concentrations in mg/Kg
SAHPLEI: As Sa Cd Cr Cu Pb Hg Se Ag
.....===ac======....====........:...a.&8a====..==........c....==&...........=.c.==...=..~.=..====..
X4820 ' 0.127 0.019 0.0003 0.006 0.013 0.075 0.0002 0.010 0.007
X4821 0.021 0.020 0.0002 0.007 0.015 0.030 0.0002 0.003 0.008
X4822 0.054 0.013 0.0001 0.006 0.013 0.009 0.0002 0.014 0.007
X4823 0.041 0.015 0.0001 0.006 0.013 0.005 0.0001 0.014 0.007
X4824 0.005 0.012 0.0001 0.007 0.015 0.026 0.0002 0.015 0.008
Ex. Blank 0.001 0.004 0.0001 0.006 0.014 0.001 0.0002 0.001 0.008
()
,,=-
-------
Sampling IS (n-5)
Concentrations In mg/kg
SAMPLE' :
[[[c......
As
Ba
Cd
Cr
Cu
Pb
Hq
Se
Ag
X4820 0.127 0.019 0.0003 0.006 0.013 0.075 0.0002 0.010 0.007
X4821 0.021 0.020 0.0002 0.007 0.015 0.030 0.0002 0.003 0.008
X4822 0.054 0.013 0.0001 0.006 0.013 0.009 0.0002 0.014 0.007
X4823 0.041 0.015 0.0001 0.006 0.013 0.005 0.0001 0.014 0.007
X4824 0.005 0.012 0.0001 0.007 0.015 0.026 0.0002 0.015 0.008
Ex. Blank 0.001 0.004 0.0001 0.006 0.014 0.001 0.0002 0.001 0.008'
Sampling 16 (n=6) Concentrations In ~/kg
SAMPLEI: As Sa Cd Cr Cu Pb Hg Se Ag
...a..=:c==-======a====a.a.....=c.c=..==C.....===....=.c......==...=.....==.&==.=.=..=.=c===~=..c=.
X4820 0.062 0.017 0.0002 0.006 0.013 0.038 0.0002 0.008 0.007
X4821 0.024 0.020 0.0002 0.007 0.015 0.030 0.0002 0.004 0.008
X4822 0.055 0.014 0.0001 0.006 0.013 0.008 0.0002 0.012 0.007
X4823 0.039 0.013 0.0002 0.006 0.013 0.004 0.0001 0.010 0.007
X4824 0.004 0.012 0.0001 0.007 0.015 0.019 0.0002 0.013 0.008
Ex. 8lank 0.001 0.004 0.0001 0.006 0.014 0.001 0.0002 0.001 0.008
5~pllng 17 (n=7) Concentrations in mg/kg
SAMPLE': As Ba Cd Cr Cu Pb Hg 5e Ag
....c==:=:-=c====.-:=-===-=::::.-=::===::..:=.......:.c.aa==e:c:===...:=:====:=....:=::==:-:=:....-
X4820 0.058 0.015 0.0002 0.006 0.013 0.057 0.0002 0.004 0.007
X4821 0.021 0.017 0.0002 0.007 0.015 0.025 0.0002 0.001 0.008
X4822 0.050 0.011 0.0001 0.006 0.013 0.007 0.0002 0.008 0.007
X4823 0.036 0.012 0.0001 0.006 0.013 0.004 0.0001 0.008 0.007
X4824 0.006 0.012 0.0001 0.007 0.015 0.020 0.0002 0.010 0.008
Ex. Blank 0.001 0.004 0.0001 0.006 0.014 0.001 0.0002 0.001 0.008
Sampling '8 (n-8)
Concentrations in mg/kg
SAMPlEl :
.C~.==.==...=2C=.=C.=.C..C..C.=CC=====..==C.....&.....ac.....accc.a......_:...............:_:a.....
As
Ba
Cd
Cr
Cu
Pb
Hg
58
Ag
X4820 0.132 0.055 0.0001 0.010 0.060 0.165 0.0002 0.024 0.007
X4821 0.059 0.060 0.0001 0.007 0.057 0.118 0.0002 0.010 0.008
X4822 0.22B 0.048 0.0001 0..006 0.037 0.028 0.0002 0.045 0.007
X4823 0.167 0.042 0.0001 0.006 0.033 0.016 0.0001 0.046 0.007
X4824 0.06B 0.047 0.0001 0.007 0.058 0.176 0.0002 0.053 0.008
Ex. Blank 0.001 0.004 0 . 0008 0.006 0.014 0.001 0.0002 0.001 0.008
Samp11ng 19 (n&9) Concentrations in mg/kg
SAMPlEl: As Ba Cd Cr Cu Pb Kg Se Ag
8&......aam..=a..a...........=..======...c..............:...........-...............:-.=-:==.......
X4820 0.146 0.067 0.0031 0.005 0.117 0.219 0.0002 0.021 0.004
X4821 0.069 0.069 0.0035 0.006 0.092 0.129 0.0002 0.006 0.004
X4822 0.249 O.O~ 0.0032 0.005 0.052 0.029 0.0002 0.032 0.004
X4823 0.IB1 0.055 0.0030 0.005 0.037 0.018 0.0001 0.095 0.003
X4824 0.030 0.052 0.004 7 0.006 0.046 0.118 0.0002 0.067 0.004
Ex. 8lank 0.001 0.005 0.0033 0.005 0.008 0.004 0.0002 0.001 0.004
Sampl'ng 110 (n-l0) Concentrations In mg/kg
SAMPLE' : As Sa Cd Cr Cu Pb Kg Se Ag
..=....8=====-............=....=-=====...&8....=.......8====.......====.............R=...==C===C...
X~820 0.140 0.081 0.0031 0.005 0.043 0.200 0.0002 0.008 0.004
X4821 0.049 0.075 0.0046 0.006 0.043 0.086 0.0002 0.003 0.004
X4822 0.253 0.057 0.0032 0.005 0.032 0.035 0.0002 0.037 0.004
X4823 0.166 0.054 0.0030 O.OOS 0.079 0..012 0.0001 0.025 0.~06 .
-------
Total Elemental ConcentratIons (FIxated Solid): Ao (~/kg)
SAMPLE' : As Ba Cd Cr Cu Pb Hg Se Ag
[[[
U820 13700 0 1250 69400 16100 8.3 106
X4821 22300 1310 103000 21300 25 154
)(4822 79200 1700 157000 20300 218 219
X4823 79200 1700 157000 20300 218 219
-------
ARCO - ANSI LONG' TERM LEACHING S1UDY
- LEACHABILI1Y INDEX
EfFEC11VE 0ifFUSIVI1Y
ELEMEN1AL CONCENTRA110NS (FROM l[ACH EXPERIMEN1) An
-Sampling '1 (n.l)
c..
SAMPLE':
...................................==.......=..=[[[
As
Ba
Cd
Cr
Cu
Pb
Kg
Se
Ag
X4820 3.6E-13 ERR 7.9E-17 ERR 4.4E-16 3.1E-14 2.7E-12 ERR 6. OE-11
X4821 7.5E-15 ERR 4.1E-16 ERR 3.1[-16 3.1[-15 4.6E-13 ERR 4.4E-11
X4822 3.7E-16 ERR 8.3E-18 ERR 8.4E-17 1.1E-16 3.8E-15 ERR 1.4E-11
X4823 9.1E-17 ERR 1.1E-17 ERR 7.3E-17 4.9E-17 3.3E-15 ERR 1.2E-l1
X4824 2.7[-18 ERR 1.4E-17 ERR 1.0E-16 1.2E-15 7.2E-14 ERR 1.6E-l1
Ex. Blank. 3.9E-18 ERR 7.3E-18 ERR 1.2E-16 2.4E-17 1.6E-14 ERR 1.8E-11
Sampling '2 (n.2)
SAMPLE': As 8a Cd Cr Cu Pb Kg Se Ag
..==..=:..==..=========..==:=::.::..:.:.:::========::-::-........-.-...:...:.=.===:.-:--..:.....=..
'X4820 8.8E-14 ERR 5.2E-16 ERR 5.8E-16 3.8E-14 3.6E-12 ERR 7.9E-ll
X4821 6.2E-15 ERR 1.1E-16 ERR 4.1E-16 1.1E-14 6.1E-13 ERR 5.8E-ll
X4822 1.0E-15 ERR 1.4E-17 ERR 1.1E-16 1. 5E-15 5.1E-15 ERR 1.8E-l1
X4823 5.2E-16 ERR 8.9E-18 ERR 9.6E-17 1.6E-16 4.4E-15 ERR 1. 6E-11
.X4824 3.6E-18 ERR 5.1E-18 ERR 1.4E-16 4.1E-15 9.5[-14 ERR 2.1E-11
Ex. 8lank. 5.2E-18 ERR 9.7E-18 ERR 1.5E-16 3.2E-17 2.1[-14 ERR 2.4E-11
Sampling '3 (n.3)
SAMPLE': As Ba Cd Cr Cu Pb Hg Se Ag
.....-.:.......::.:=.....:.:=::.:::.::::-:-.:..:-:=-:.................=........:.............-.....
X4820 1. 2E -13 ERR 1.8E-17 ERR 7.6E-16 8.9E-14 1.7E-12 ERR 2.4E-ll
X4821 7.4E-15 ERR 2.6[-17 ERR 2.5E-16 2.6E-14 2.9[-13 ERR 1.7E-l1
X4822 3.0E-15 ERR 9.7£-18 ERR 3.3£-17 2.1£-15 2.4E-15 ERR 5.4E-12
X4823 1.7[-15 ERR 8.5[-18 ERR 5.3E-16 6.3E-16 2.1E-15 ERR 4.7E-12
X4824 3.4E-17 ERR 4.5E-18 ERR 4.1E-17 1.1E-14 4.4[-14 ERR 6.2E-12
Ex. Blank. 1. 5E -18 ERR 8.6[-18 [RR 4.6E-17 9.4E-18 9.7E-15 ERR 7.1[-12
S~mplln9 '4 (n.4)
SAMPLE': As BI Cd Cr Cu Pb Hg Se Ag
.....a.......a.=======:=:.....:..:....-........==:........................:=.:..........-..........
X4820 1.7[-13 ERR 2.3E-17 ERR 2.1E-16 1.1E-13 2.1E-12 ERR 2.9E-ll
X4821 7.8E-15 ERR 3.2E-17 ERR 1.5E-16 3.0E-14 3.5E-13 ERR 2.1E-11
X4822 4.3E-15 ERR 1.2E-17 ERR 4.1E-17 2.8E-15 2.9E-15 ERR 6.7E-12
X4823 2.2E-15 ERR 1.0E-17 ERR 3.5E-17 6.9E-16 2.5E-15 ERR 5.8E-12
X4824 3. 6E -17 ERR 5.5E-18 [RR 5.0[-17 9.5E-15 5.5E-14 ERR 7.7E-12
Ex. Blank 1.9[-18 ERR 1.1E-17 ERR 5.7E-17 1.2E-17 1.2E-14 ED 8.8[-12
Sampling '5 (n.5)
SAHPlEl: As 81 Cd Cr Cu Pb Hg Se Ag
....................-..................-.:........-................................................
X4820 9.2E-13 ERR 4.7E-16 ERR 3.6E-16 2.3E-13 3.5E-12 ERR 5.0E-ll
X4821 1.1[-14 ERR 3.1[-16 [RR 2.5[-16 2.5E-14 6.0[-13 ERR 3.6E-ll
X4822 4.6E-15 ERR 3.4E-17 ERR 6.9E-17 2.2E-15 5.0E-15 ERR 1.1E-ll
X4823 2.5E-15 ERR 3.5E-17 ERR 6.0E-17 5.6E-16 4.3E-15 ERR 9.8[-12
X4824 4.9E-17 ERR 2.4E-17 ERR 8.5E-17 7.0E-15 9.3E-14 ERR 1.3E-ll
-------
Sampling 16 (n=6)
SAJoIPLE' : As Ba Cd Cr Cu Pb Hg Se Ag
...c.....==-==========:===:==:=...............:a.a:_.-.c......ca==.==..======....caa===....==...c=-
1.4820 3.0E-13 [RR 3.1E-16 ERR 5.1E-16 8.5E-14 4.9E-12 ERR 7. DE -11
1.4821 2.0E-14 ERR 3.7E-16 ERR 3.6E-16 3.6[-14 8.4E-13 ERR 5.1Hl
1.4822 6.7E-15 ERR 4.1E-17 ERR 9.7E-17 1.9E-15 7.0E-15 ERR 1. 6E-11
1.4823 3.3E-15 ERR 1.8E-16 ERR 8.4E-17 5.3E-16 6.1E-15 ERR 1.4E-11
1.4824 3.9E-17 [RR 1.9E-17 ERR 1.2E-16 5.4E-15 1.3E-13 ERR 1. 8E-11
Ex. Blank 4.5E-18 ERR 2.5E-17 ERR 1.4E-16 3.2E-17 2.9E-14 ERR 2.1E-11
Samp 11 ng f7 (n..7)
SAMPLE': As Ba Cd Cr Cu Pb Hg Se Ag
..c~=aa==c.===c========c=...====.=D...C.=..=====c=..=..aacca.a...e=ace..a==ce....:............:....
1.4820 3.4E-13 ERR 4.4E-16 ERR 6.6E-16 2.5E-13 6.4E-12 ERR 9 . DE -11
1.4821 1.9E-14 ERR 4.4E-16 ERR 4.6E-16 3.1E-14 1.1E-12 ERR 6.6E-11
1.4822 7.3E-15 ERR 4.5E-17 £RR 1.3E-16 2.2E-15 9.0£-15 ERR 2.1E-11
1.4823 3.6E-15 [RR 3.2E-17 £RR 1.1E-16 8.1[-16 7.8E-15 ERR 1.8E-11
1.4824 1 . OE -16 ERR 3.3E-17 ERR 1. 5E-16 7.4E-15 1.7£-13 ERR 2.4[-11
Ex. Blank 5.9E-18 ERR 3.3E-17 ERR 1.8E-16 3.6E-17 3.7£-14 ERR 2.7H1
Sampling '8 (n..8)
SAMPLE': As Sa Cd Cr Cu Pb Hg Se Ag
aa===..===acs================..==aaa.======_==_cDca.....a:.c.-.:c....c:=................._.........
1.4820 2.4E-14 ERR 9.5E-19 £RR 1.9E-16 2.7E-14 8.6E-14 ERR 1.2H2
1.4821 2.2E-15 ERR 1.3E-18 ERR 9.4E-17 9.3E-15 1. 5E-14 ERR 8.9[-13
1.4822 U)E -15 ERR 5.0E-19 ERR 1.3E-17 4.7E-16 1.2E-16 ERR 2.8E-13
1.4823 1.0E-15 ERR 4.3E-19 ERR 1.0E-17 1.4E-16 1.1E-16 ERR 2.4E-13
1.4824 2.0E-16 ERR 6.7E-19 ERR 3.2E-17 7.8E-15 2.3E-15 ERR 3.2E-13
Ex. Blank 7.9E-20 ERR 4.4E-17 ERR 2.4E-18 4 .8E -19 5.0E-16 ERR 3.7E-13
Sampling '9 (n=9)
SAMPLE': As Sa Cd Cr Cu Pb Hg Se . Ag
a....a.a.....as:====:=......==-_:=_._.==......=::===...e.a.._.-.=:====.....................-.-.:=..
1.4820 1.9E-14 ERR 1.0E-15 ERR 4.9E-16 3.1E-14 5.6E-14 ERR 1.9E-13
1.4821 1.9E-15 ERR 1.4E-15 ERR 1.6E-16 7.0£-15 9.2E-15 ERR 1.3E-13
1.4822 1.6£-15 £RR 5.5£-16 £RR 1.8£-17 3.1E-16 7.9£-17 ERR 4.3E-14
X4823 7.8£-16 £RR 4.7£-16 £RR 8.3E-18 1.2E-16 6.9£-17 ERR 3.8E-14
1.4824 2.5£-17 ERR 4.4£-16 ERR 1.3£-17 2.3£-15 1.5£-15 ERR 5.0E-14
Ex. 81ank 5.2£-20 £RR 4.8E-16 ERR 5.3E-19 4.1£-18 3.2£-16 ERR 5.7E-14
Samp1'ng '10 (n-10)
SAMPLE': As Sa Cd Cr tu Pb Hg Se Ag
_..................=..c............c.............a........=ac......................................
1.4820 1.5£-14 £RR 8.6E-16 ERR 5.5E-17 2.2£-14 4.6£-14 ERR 1.6£-13
X4821 8.1£-16 ERR 2.0E-15 ERR 2.9E-17 2.7£-15 7.9£-15 ERR 1.1E-13
X4822 1.3£-15 ERR 4.5E-16 ERR 5.5E-18 3.9£-16 6.5£-17 ERR 3.6E-14
X4823 5.4E-16 ERR 3.9£-16 ERR' 4.3£-18 4.6E-17 5.7E-17 ERR 7 .9E-14
X4824 5.8E-18 ERR 2.1£-16 ERR 3.7E-18 7.1E-16 1.2E-15 ERR 4.1E-14
Ex. Blank 4.3E-20 ERR 4.0E-16 ERR 4.4E-19 5.6E-19 2.7E-16 ERR 4.7E-14 "
';')
ue:-
-------
ARCO . ANSI LONG TERM lEACHING STUDY
. LEACHABILITY INDEX
LEACHABILITY INDEX
SAHPLEI: As B4 Cd Cr Cu Pb Hg Se Ag
...........D..=~==c...c..===.........'..=[[[
X4820 10.6 ERR 13.42 ERR 13.4 11.0 9.60 ERR B.39
X4821 12.1 ERR 13.29 ERR 13.6 11.7 10.4 ERR B.53
X4822 12.5 ERR 13.93 ERR 14.2 12.9 12.5 ERR 9.04
X4B23 12.8 ERR 13.94 ERR 14.0 13.4 12.5 ERR 9.10
U824 14.3 ERR' 14.12 ERR 14.1 12.3 11.2 ERR 8.98
-------
1-1-~
.RCO ;.~
Post Offtce Box 1491
SUite 301. First Secunty Bank BuddIng
307 East Pane Street
Anaconda. Montana 59711
Telephone 406 563 5211
FacsImile 406 563 8269
" .
-.
CERTIFIED MAIL -- RETURN RECEIPT REQUESTED
July 31, 1991
"\
"": t:'....~
,."'.. .."..
-. . .-
Mr. Charles Coleman
Anaconda Project Manager
U.S. Environmental Protection
Region VIII, Montana Office
Federal Building
301 S. Park, Drawer 10096
Helena, MT 59626-0096
Agency
Mr. Gregory Mullen
Solid & Hazardous Waste Bureau
Montana State Department of
Health & Environmental
Sciences
Cogswell Building
Helena, MT 59620
ARCO's Comments on Anaconda Smelter site, Flue Dust Operable
Unit, Proposed Plan
Dear Mr. Coleman and Mr. Mullen:
Re:
ARCO submits the following comments on EPA's June 1991 Anaconda
Smelter site, Flue Dust Operable unit Proposed Plan (the "Proposed
Planll). These comments supplement our July 23, 1991 comments to Mr.
Coleman, which are attached hereto as Exhibit A and incorporated by
reference.
I.
GENERAL COMMENTS
ARCO .strongly supports EPA' s selection of Al ternati ve 4, Onsi te
Stabilization/Fixation, Disposal in an Onsite Repository, as the
preferred alternative for the Flue Dust Operable unit. The final draft
RI/FS . clearly requires identification of Alternative No.4 as the
preferred alternative under the NCP remedy evaluation criteria and
CERCLA's statutory mandates. In further support of Al ternati ve No.4 as
the preferred alternative, ARCO incorporates by reference the following
documents into these ,comments:
1) the above-referenced July 23, 1991 letter to EPA;
2) ARCO's May 22, 1991 letter to EPA and the State regarding the
"Identification of Stabilization/Fixation as the Preferred
Alternative for the Flue Dust Operable Unit", attached hereto as
Exhibit B: .
3) ARCO's May 9, 1991 letter to EPA providing a sensitivity
analysis of the net present costs for Alternatives 4, 5 and 6,
attached hereto as Exhibit c.
4) ARCO's April 29, 1991 letter to EPA, "Evaluation of Innovative
and Resource Recovery Technologies under CERCLA and the NCP'for the
Flue Dust Operable Unit", attached hereto as Exhibit D.
<-1
AttantiC Ric:IIf.etcj Company
ARCO~O
-------
Mr. Charles Coleman
Mr. Gregory Mullen
July 31, 1991
Page 2
~'
II.
SPECIFIC COMMENTS
ARCO has the following specific comments:
A. Summary of site Risks. The Proposed Plan contains a section
entitled "Summary of Site Risks." ARCO disagrees with the conclusions
set forth in this section, and incorporates by reference the following
documents into these comments:
1) Scoping Document - August, 1989
2) ARCO's Comments on EPA's Risk Assessment - August, 1990
B. ARARs. Appendix B, Vol. II of the Final Draft RI/FS contains
EPA's "Screening and Description of Potential ARARs for the Flue Dust
Operable Unit, Anaconda Smelter NPL Site, January 1991." ARCO provide"
EPA with comments on this document by letter dated May 20, 1991,
attached hereto and incorporated herein as Exhibit E.
The Proposed Plan also indicates that "design requirements for
repository would meet. . . some relevant and appropriate MHWA and RC~
Subtitle C requirements." We stress that only those requirements tha
clearly are within'the scope of the Flue Dust Operable Unit should b
identified as ARARs. Addit10na11y, ARCO continues to believe that RC
subtitle C requirements should not be identified as ~~s for
Alternative 4, where the treated flue dust will not exceed TCL
regulatory limits. Rather, design of the repository should be based upo
best engineering judgment in the design phase. .
ARCO incorporates by reference our previous comment on ARARs.
.including:
1) ARCO's May 16, 1990 letter updating ARCO's ARARs Scopin
Document, attached hereto as Exhibit F.
2) ARCO's August 31, 1989 ARARs Scoping Document For the Flue Dus
Operable unit.
The specific documents and comments set forth above are int~nde(
to. supplement and not in any way to limit or supersede our previou~
communications and correspondence with the Agency pertaining to the Flu
Dust Operable unit.
POOR QUALITY
ORIGINAL
-------
Mr. Charles Coleman
Mr. Gregory Mullen
July 31, 1991
Page 3 .
ARCO respectfully requests that EPA carefully consider the above-
comments in selecting the final remedy for ,this Operable Unit.
RJB/mk
cc:
.5. M. stash
P. s. Sbar, Esq.
R. W. Lawrence, Esq.
-------
ARCO
"
. ,
Pes: QU,ee 801 "91
Sv.le 301. F,~I Secunty Bank BUlld,ng
307 Easl Park Streel
Anatonda. Monlana 59711
Teleottone 406 56J 5211
F atSlmlle 406 563 8269
July 23, 1991
Mr. Charles Coleman
u.s. Environmental Protection
Region VII!, :~ontana Office
Federal Building
301 S. Park, Drawer 10096
Helena, Montana 59626-0096
Dear Charlie:
Agency
The EPA's Proposed plan for the remediation of the F1Ue
Dust Operabl~ Unit at the Anaconda Smel~ Site ~~en
reviewed by ARCa, and we agree with "SPA' $ analysis.
Accordingly, we will support the decision to use ~n.s1~e
solidification/fixation.
Also, we would like to add the following comments
regarding the criteria employed by EPA to select the
preferred alternative.
Long-term Effectiveness and Performance. Two leaching
methods were used to predict the long-term stability of
the fixed and solidified flue dust samples. There are no
procedures which will unequivocally predict long-term
stability. However, the Multiple Extraction Procedure
(MEP) and the ANS 16.1 have been proposed by EPA in the
publication, "EPA/624/6-89/122" as methods for
determining maximum leachate concentrations which could
occur under acidic environments. The results obtained
from such tests are thought to simulate long-term
leaching behavior.
However, since a degree of uncertainty remains, part of
EPA's propo5P.d ~ is containment of the treated
material in an eRlar~ .reposi tory which will (1) preve.nt .
inward leakage of a~~ ~id - acidic or not, (2) minimize
outward leakage of leachate, and (3) preserve protective
alkalinity. We submit that these precautionar~ measures
should be used for ~ flue dust residues conta~ning high
~evels of potentially leachable heavy metals.
&I:a"~ : ~.(f".'...c C::nDI"'-
:.=,::=.....-,0:-.
-------
The complexity and potentially hazardous nature of the
Cashman technology as applied to flue dust is illustrated
by the outcome of a Hazard and operating Study (HazOp)
conducted for ARCO by a team of consultants in September,
1990. The subject was Bechtel's design of a Cashman
plant to treat Anaconda flue dust, and the object of the
study was to identify hazards to operators and to the
environment, as well as operability problems which could
compromise the plant's ability to achieve and sustain
design throughput and required residue leachability. The
principal intent was to reveal safety hazards and to
develop accident scenarios, while only limited attention
was given to operability problems and economic
consequences. A mYQh more detailed study subsequent to
further piloting would be needed to quantify the latter.
Over 600 safety-related accident scenarios were developed
and over 100 design modifications were identified which
needed 'correction to meet either OSHA regulations or to
comply with the operating principles of responsible plant
managers.
~,
For example, the design suffers from many examples of
highly potential spills of hot liquids and slurries,
generat~on and release of hydrogen/air mixtures, and the
like. There also is, a significant potential for
autoclave explosions.
The HazOp Study concluded with the following paragraph:
"...Although each individual unit operation in the
process is relatively simple, the combined process is
very complex. It requires extensive recycling and
careful control of process parameters through every step
of the treatment. The process is operator-intensive,
thereby being prone to human errors and operability
problems. Addition of interlocks to improve the safety
of the system by reducing the potential for human error
could make the system even more difficult to operate. .
From an economic perspective, numerous accidents were
identified which were not safety-related but would cause
contamination of products~ It should be assumed that a
significant portion of ti1e facility life is (would be)
spent reprocessing these contaminated products."
Cost. The operating cost uncertainties of a batch plant
are small, reflecting mainly fluctuations in cement price
and the rental rates. of equipment and operators. Both
capital and operating cost estimates for the fir.st
commercial application of a complex processing technology
are very uncertain - even when based on very detailed
plant design, which has not yet been done for the Casrunan
Process. Invariably, these estimates qrow as more is
learned about a process and more detailed engineering has
been completed. Early "optimism" with regard to costs
-------
<.
usually reflects failure to consider fully the
engineering obstacles which must be overcome. It is
likely that satisfaction of the HazOp findings alone
could add 50 to 100 percent to the preliminary capital
cost estimate and increase operating costs significantlY.
In summary, ARCO believes that the data provided in the
Flue Dust RI/FS accurately portray the problem and define
the remedial alternatives ~hich are currently available.
The Comparative Analysis of Alternatives ~rovided by the
BPA clearly shows that Solidification/Fl.Xation is the
preferred remedy, as it can be accomplished quickly using
a simple process to eliminate the problem permanently. .
cc: Greg Mullen
Pam Sbar, Esq.
Bob Lawrence, Esq.
Robin Bullock
Terry McNulty
-------
I......,"; ,-.'" -')/,-
, "/'J-::>U'''''-
ARCO Coal Compan)
PO Bo. U~,
Anacor.:. M,:)nun. !I~7"
Ttir;>"onr I'C6, !l6~ ~111
~~
~,
May 22, 1991
Hr. Charles Coleman
Environmental Protection Agency
Region VIII, Montana Office
Federal Building
301 S. Park, Drawer 10096
Helena, Montana 59626-0096
VIA HAND DELIVERY
A. Lensink, Esq.
Environmental Protection Agency
Region VIII
Office of Regional Counsel
One Denver Place
999 18th ,Street
Denver, Colorado 80202-2413
VIA FEDERAL EXPRESS
VIA FEDERAL EXPRESS
VIA FEDERAL EXPRESS
Mr. Duane Robertson
Montana Department of Health
and Environmental Sciences
cogswell Building
Helena, Montana 59620
subject:
Laura Bassein, Esq.
Legal Division
Montana Department of Health
and Environmental Sciences
Cogswell Building
Helena, Montana 59620
Identification,of Stabilization/Fixation as the Preferred
Alternative for the Flue Dust Operable Unit
Gentlemen and Ms. Bassein:
This letter addresses ARCO's identification of a preferred
remedial alternative for the Flue Dust Operable unit at the
, Anaconda Smelter site (the "Site"). In an April 29, 1991 letter to
Kr. Lensink from ARCO I S counsel, Mr. Lawrence ~ ARCO agreed to
delete the preferred alternative section that was included in the
March 1, 1991 Preliminary Draft Flue Dust Operable unit Remedial
Investigation/Feasibility Study ("RIfFS"), with the understanding
that ARCO could identify the preferred alternative in a separate
submittal. The preliminary Draft RI/FS identified
stabilization/fixation as the preferred alternative for the Flue
. . Dust Operable unit. The comparative analysis in the Final'Draft
RIfFS demonstrates that stabilization/fixation must be the
preferred alternative for the site under the evaluation criteria
and remedy selection process set forth in the National Contingency
Plan ("NCP"), 40 CFR Part 300.
EPA is required under the NCP to develop a proposed plan which
iden.tifies the prefex'red alternative for the site. 40 CFR
5300.430(f) (2) ("The proposed plan"). EPA must also discuss in the
proposed plan the rationale that supports the preferred
-------
Hr. Charles Coleman
Hr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
Hay 22, 1991
Page 2
alternative. 40 eFR 5 300.430(f) (2) (1i). The following discussion
identifies stabilization/fixation as the preferred alternative for
the site and sets forth the rationale for its selection.
1:.
The Remedy Selection Process.
The National contingency Plan ("NCpn) mandates a comparative
remedy selection process using nine specific criteria:
A detailed analysis shall be conducted on the limited
number of alternatives that represent viable approaches
to remedial action after evaluation in the screening
stage. . .. The detailed analysis consists of an
assessment of individual alternatives against each of
nine evaluation criteria and a comparative analysis that
focuses upon the relative perfonnance of each alternative
against those criteria.
40 eFR S 300.430(e) (9) (i) and (ii) ("Detailed analysis of
alternatives"); see iUJ2.Q 40 CFR S 300 ~ 430 (e) (9) (iii) ("Nine
criteria for evaluation").
The NCP discusses the'nine criteria and their relative weight
as follows:
The [nine criteria] are used to select a remedy.
criteria are categorized .into three groups.
(A) Threshold criteria. Overall protection of human
heal th and the environment and compliance with ARARs
. . . are threshold requirements that each alternative
must meet in order to be eligible for selection.
These
POOR QUALITY
40 CFR S 300.430(f) (1) (i) ("Selection of remedy"QRIGINAL
(B) PrimarY bala~cina criteria. The five primary
balancing criteria are long-term effectiveness and
permanence; reduction of t~xicity, mobility, or 'vol.u.:::e
through treatment; short-term effectiveness;
implementability; and cost. . .
(C) Hodifvina criteria. state and community acceptance
are modifying. criteria that shall be considered in remedy
selection. . . .
-------
Mr. Charles Coleman
Mr. Duane Robertson
A. Lensink, Esq.
~ura Bassein, Esq.
Hay 22, 1991
Page 3
The detailed analysis of remedial alternatives for the site
under the threshold and balancing criteria has been completed and
is discussed in detail in Volume II of the April 30, 1991 Final
Draft. The alternatives that were analyzed are: (1) no action;
(2) onsite disposal; (3) off-site disposal; (4)
stabilization/fixation; (5) (A) Cashman Process with
stabilization/fixation; (5) (B) Cashman Process without
stabilization/fixation; and (6) ambient acid leach process. Table
10.3-9 in the FS summarizes the evaluation of these alternatives
under the threshold and balancing criteria and is attached for your
reference as Attachment A. Alternatives 4, SA and 6 all rely upon
treatment with cement based stabilization/fixation to produce a
stable, non-toxic material for disposal in a designed on-site
repository.
As discussed below, a comparative analysis of these
alternatives under the two threshold and five balancing criteria
(the modifying criteria have not yet been applied) clearly results
in selection of alternative number 4, stabilization/fixation, as
the preferred alternative for the site.
11.
COMPARISON OF ALTERNATIVES UNDER THE THRESHOLD CRITERIA
A comparative analysis of alternatives is set forth in section
.10.4 of the FS, based upon the detailed analysis of alternatives in
section 10.3. The discussion below is intended to supplement the
discussion in the FS.
rrote~t!o~st~~~l~~:;~on~iO~n~:es~p~~~~:;~~t ;;anGrQ~~;~
Alternatives. The NCP requires that the remedial action selected
. "shall be protective of human health and the environment.. 40 CFR
S 300.430(f)(1)(ii)(A). This is the first of the two threshold
criteria. ~ 40 CFR S 300.430(f)(1) (i) (A). Only stabilizationl
fixation received a positive ranking relative to the other
alternatives for protection of human health and the environment.
The No Action alternative received a negative ranking, and all of
the other alternatives received a neutral ranking. See Table 10.4-
1, comparative Analysis of Alternatives, RI/FS at 142 ("comparative
Analy~is Table") (attached hereto as Attachment B).
stabilization/fixation's positive ranking for protection of
human health and the environment reflects the fact that it received
high rankings under the other evaluation criteria. As the NCP
explains, 8 [o)verall protection of human health and the environment.
"
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Mr. Charles Coleman
Mr. Duane Robertson
A. t.ensink, Esq.
Laura Bassein, Esq.
Hay 22, 1991
Page 4
draws on the assessments of other evaluation criteria, especially
long-term effectiveness and permanence, short-term effectiveness,
and compliance with ARARs." 40 CFR S 300.430(e) (9) (iii) (A). The
comparative rankings under the other evaluation criteria are
discussed below. In brief, however, stabilization/fixation is
superior in its overall protection of health and the environment
because it uses "a standard, proven [treatment) technology to
produce a stable, non-toxic material for onsite disposal in a
timely manner." RI/FS at 143.
B. stabilization/Fixation ~ttains ARARs. The NCP also
requires that the selected alternative "attain those ARARs that are
identified at the time of -ROD signature or provide grounds for
invoking a waiver. . . .n 40 CFR S 300.430(f) (l)(ii)(B). This is
the second threshold criterion. $ee, 40 eFR S 300.430(f) (1) (i) (A).
All of the alternatives attain ARARs, except for the No Action
alternative which received a negative ranking under the second
threshold criterion.
To summarize, stabilization/Fixation attains ARARs and
provides the highest degree of short and long-term protection of
human health and the environment relative to the other remedial
alternatives for the site.
III. ~omDarison of ~lternatives Under the Balancina criteria.
1.. ta at 0 xat. 0 r a s ve 0 he e s
Under The Balancina criteria. stabilization/fixation received the
highest combined ranking under the five balancing criteria, with
four positive rankings and one neutral ranking for cost. Relative
to the other alternatives, it provides greater or equivalent long-
term effectiveness and permanence, reduction of toxicity, mobility,
or volume, short-term effectiveness and implementability. :;ee
comparative Analysis Table.
1. Short-term effectiveness. The time taken- u~til
protection is achieved is a key component of the - short-ten
effectiveness evaluation. ~ee 40 CFR S 300.430(e) (9) (iii) (E).
ARCO projects in the FS that stabilization/fixation would have a
three __year implementation period, compared with a JDinimum seven
year period for implementation ~f the Cashman Process or the
ambient acid leach process. The actual time periods for
implementation of Cashman and the ambient acid leach process are
likely to be sUbstantially longer than seven years given
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Mr. Charles Coleman
Mr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991
Page 5
uncertainties associated with the development and operation of
these technologies at full-scale.
The preamble to the proposed NCP expressly provides that when
~~e ~~t:~native would reauire more time to complete ard would have
d~~~;i~n:.m~~;~te~ui~:acft:C~~ h~~an t~:al ~~s~~~;~fo~~v ~~:~;. ~~:
~lternatives under the short-term effectiveness criterion." 55 Fed.
Reg. 8725 (March 8, 1990) (emphasis added.)' ARCO believes that the
time taken until protection is achieved under the short-term
effectiveness criterion weighs heavily in favor of
stabilization/ fixation, particularly in 1 ight of the
implementability concerns associated with the other treatment
alternatives. Additionally, stabilization/fixation involves the
fewest number of untreated flue dust handling steps when compared
with the Cashman Process or the ambient acid leach process,
resulting in less potential short-term impacts on human. health.
2. Implementabilitv. A comparison of alternatives under the
implementability criterion is especially instructive and clearly
favors stabilization/fixation over other the other treatment
alternatives. stabilization/fixation technology is well-known, and
is simple to construct and operate. This process mixes cement and
other additives with the flue dust using standard, readily
available equipment to make a stable concrete and is quite similar
to the methods used for making structural concrete. The Cashman
and ambient acid leach processes, on the other hand, are complex
both to construct and to operate. There remain significant unknowns
associated with the construction, operation and reliability of
these technologies.
For example, the Cashman Process has yet" to be proven at
full scale for treating flue dust materials. Optimization of the
unit operations would be necessary prior to design of a full scale
facility. In general, the pilot-scale plant was unable to produce
precipitate products which would meet expected design criteria. Due
to pressure and temperature requirements and composition of
solutions throughout the Cashman Process, c01I1paratively exotic
construction materials likely would be necessary. significant
uncertainty still exists with. respect to the basic question of
whether the process can produce a residue that does not exceed TCLP
regulatory limits.
similarly, while several currently operating co;mercial plants
use acid leach technology, flue dust has never been processed with
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-
Mr. Charles Coleman
Mr. Duane Robe.rtson
A. Lensink, Esq.
Laura Bassein, Esq.
Hay 22, 1991
Page 6
this technology at a !ull scale. Specific concerns related to the
implementability of ambient acid leach process include concerns
with acid leaching, solvent extraction, and lime precipitation.
optimization pilot testing ,,",ould be necessary to address the
unknowns associated with the operation and reliability of the
ambient acid leach process.
Under the Cashman Process with stabilization and the ambient
acid leach process alternatives, the residues and materials from
these processes would still require stabilization/fixation prior to
disposal in a repository. It defies common sense to spend at least
seven years implementing these technologies only to generate
residues that would continue to exceed TCLP limits and would still
require stabilization/fixation, when the same end result (disposal
of treated, stable material in an on-site repository) could be
achieved in under three years with a simple, proven treatment
technology like stabilization/fixation.
3. ' Reduction of toxicity. mobility. or volume throuqh
~reatment. The stabilization/fixation, Cashman Process and ambient
acid leach alternatives are comparable under this criterion only
because the final step for alternative SA (cashman Process 'with
stabilization/fixation) and the ambient acid leach process is
stabilization/fixation followed by disposal in a designed
repository. We bave assumed for purposes' of Alternative SB that
the Cashman Process can produce a residue that does not exceed TCLP
requlatory limits. It should be noted that substantial uncertainty
exists with respect to this assumption at full s'cale operation. RI
Phase II treatability data indicate that the Cashman Process
potentially may produce a leach residue exceeding TCLP regulatory ,
limits for lead. The ambient acid leach process also is expected
to produce residues and precipitate exceeding TCLP regulatory
limits for lead and cadmium. In the event that residues and other
materials exceed TCLP regulatory limits, further treatment with
stabilization/fixation will be necessary to reduce the toxicity and
mobility of these materials. The onsite and offsite disposal
alternatives for untreated flue dust would not result in reduction
of toxicity, mobility or volume through treatment.
, 4. Lana-term .protectiveness and Permanence.
stabilization/fixation prov1des equivalent or greater long-term
protectiveness and permanence than the other alternatives
evaluated.
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Hr. Charles Coleman
Hr. Duane Robertson
A. Lensink, Esq. .
Laura Bassein, Esq.
Hay 22, 1991
Page 7
5.~. Cost is the only criterion for which
stabilization/fixation did not receive a ranking equal to or higher
than all of the other alternatives in the comparative analysis of
clternatives. stabilization/fixation received a neutral ranking
for cost, while the onsite disposal and ambient acid leach process
alternatives received positive rankings. ~. However, the onsite
disposal alternative does not address CERCLA's and the NCP's
preference for alternatives involving treatment. ~ 40 CFR
S 300.430(f)(1)(ii)(E)(tlThe balancing shall also consider the
preference for treatment as a principal element. . ."). Moreover,
the cost sensitivity analysis that ARCO provided to EPA on May 9,
. 1991 (attached hereto as Attachment C) shows that the degree of
variation for the net present value cost at a 10% discount rate for
the ambient acid leach process is almost a factor of six, ranging
from a low of $6.5 million under a best case scenario to a high of
$34.7 million under a worst case scenario. This reflects the high
degree of uncertainty that exists regarding the capi tal
construction costs for the ambient acid leach process, and
potential variability in the price of copper. ARca expects that
the worst case scenario is more l~kely to occur than the best case
scenario. Although the ambient acid leach process and
stabilization/fixation alternatives have comparable expected costs
($19.2 million and $21 million respectively), the ambient acid
leach process exhibits much more uncertainty in its upper and lower
range. The stabilization/fixation alternative shows the least
variation amongst treatment alternatives 'in net present value at a
. 10' discount rate, indicating that process parameters for this
alternative are well known. Based upon: 1) the uncertainty and
degree of variation .of the net present value cost. for the ambient
acid leach process; 2) the' relative certainty and very limited
variation of the net present value cost for stabilization/fixation1
and 3) the comparable expected net present values of both the
ambient acid leach process. and stabilization/fixation, ARca has
revised Table 10.4-1 to reflect a neutral cost ranking for the
ambient acid leach process relative to other alternatives.
.. .
v-
B. summarY of COD\par~son of Alternatives Under the Balancinq
criteria. To summarize, with a total of' four positive rankings
under long-term effectiveness and permanence, reduction of
toxicity, mobility, or .volume through treatment, short-term
effectiveness, an4 implementability, and a neutral cost ranking,
stabilization/fixation is by far the superior alternative under the
five balancing criteria.
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Mr. Charles Coleman
Mr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991
Page 8
IV. Determination of Cost-Effectiveness.
section 121(b) of CERCLA requires that EPA select a remedial
action that is cost-effective. The NCP explains the method EPA is
to use to make a cost-effectiveness determination:
Each remedial action selected shall be cost-effective...
.[which] is determined by evaluating the following three
of the five balancing criteria ... to determine overall
effectiveness: long-term effectiveness and permanence,
reduction of toxicity, mobility, or volume through
treatment, and short-term effectiveness. Overall
effectiveness is then compared to cost to ensure that the
remedy is . cost-effective. A remedy shall be cost-
effective if its costs are proportional to its overall
effectiveness.
40'CFR S 300.430(f)(1)(ii)(D). The preamble to the NCP further
explains that, iri determining cost-effectiveness, the reliability
of treatment technologies are to be considered under the criterion
of reduction of toxicity, mobility or volume through treatment, and
that the reliability of long-term management controls to address
treatment residuals [such as a repository] is to be considered
under long-term effectiveness and permanence. 5S Fed. Reg. i727.
stabilization/fixation is clearly the cost-effective
alternative for the Flue Dust Operable unit. stabilization/fixation
alone among the alternatives evaluated received a positive ranking
under each of the three balancing criteria listed above in the NCP
for determining overall effectiveness. The ambient acid leach
process and Cashman Process with stabilization received positive
rankings for long-term effectiveness and permanence and reduction
of toxicity, mobility or volume; but the former received only a
neutral ranking for short-term effectiveness and the latter
received a negative ranking for that criterion. Furthermore, .there
is much uncertainty regarding the reliability of the ambient acid
leach process and the Cashman Process as they apply to flue dust.
Each of the remaining remedial alternatives received just one or no
positive rankings under the three criteria used to measure overall
effectiyeness. See Comparative Analysis Table.
stabilization/fixation received a neutral ranking for the cost
criterion relative to the other alternatives. The onsite disposal
and ambient acid leach process alternatives received positive
rankings; however, the cost ranking for the ambient acid leach
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Mr. Charles Coleman
Mr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991
Page 9
process should be revised to neutral for the reasons discussed
above. Offsite disposal and the Cashman Process received negative
rankings for cost.
When comparing stabilization/fixation's ranking for cost to
its superior ranking for overall effectiveness, stabilization/
fixation best meets the cost-effectiveness requirement, ~, its
costs are highly proportional to its overall effectiveness. EPA
uses the term "proportional" because "it intends that in
determining whether a remedy is cost effective, the decision-maker
should both compare the cost to effectiveness of each alternative
individually and compare the cost and effectiveness of alternatives
in relation to one another." 55 Fed. Reg. 8728. "If the difference
in effectiveness is small, but the difference in cost is very
large, a proportional relationship between the alternatives does
not exist." .~ stabilization/fixation among all of the
alternatives most offers "a reasonable value for the money in light
of the results [it] achieves." 55 Fed. Reg. 8729.
This requirement shall be fulfilled by selecting the
alternative that satisfies [the two threshold criteria]
and provides the best balance of trade-offs among
alternatives in terms of the five balancing criteria. .
.. The balancing shall emphasize long-term
effectiveness and reduction of toxicity, mobility or
volume through treatment. The balancing shall also
consider the preference for treatment as a princip~l
element and the bias against off-site land disposal of
untreated waste.
M.
In short, the NCP provides that the determination of whether
the selected remedy utilizes permanent solutions and alternative
treatment or resource recov.ery technologies to the maximum extent
practicable must be addressed In terms of the two threshold and
fjve balancing criteria. No separate criterion exists for making
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Hr. Charles Coleman
Hr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991 .
Page 10
this determination. See Preamble to the NCP, 5S Fed. Reg. 8719
(March 8, 1990) ("EPA is not adding as a criterion the . . .
mandate to utilize permanent solutions and alternative treatment
technologies or resource technologies to the maximum extent
practicable. The analysis performed pursuant to the nine criteria
concludes with selection of a remedy that meets the mandate.")
ARCO provided EPA with a letter dated April 29, 1991, attached
hereto as Attachment D, which explains how the statutory directive
is to be implemented with respect to resource recovery
technologies.
Of all the alternatives, stabilization/fixation best satisfies
this statutory mandate as implemented in the NCP.
stabilization/fixation is a permanent solution that utilizes
treatment technologies to the maximum extent practicable.
stabilization/fixation satisfies the two threshold criteria and in
fact received the highest net ranking for those crit~ria in the
comparativ'e. analysis in the FS. stabilization/fixation, the
Cashman Process, and the ambient acid leach process all received
positive rankings with respect to the long-term effectiveness and
permanence and reduction of toxicity, mobility or volume through
treatment criterial, two of the five balancing criteria which
require emphasis under the NCP in the balancing process. ~
Comparative Analysis Table. In such circumstances, the preamble to
the proposed NCP expressly provides that,
When the alternatives provide similar long-term
effectiveness and permanence, and reduction of toxicity,
~obility or volume, the other balancing criteria rise to
distinguish the alternatives and playa more significant
role in selecting the remedy. For example, if two
alternatives offer similar degrees of long-term
effectiveness and permanence and reduction of toxicity,
mobility or volume through treatment, but one alternative
would reauire more time to complete and would have
0' eater short-term 'm acts on human health and. he
environment. the decision-maker ~ould focus 0" the
, The Cashman ProeHl wfthout Itabmution/fixation alt8mati¥t recei...ed . nevtraI ranking for long "rm lffe<:tMnela and
permane nee beca.uM of uncer1altrti" concerning the ctwacteristicl of the reliduals pC'oduced by the proceu. ~a1ionlfixation.
Cashman foI\Ow8d by $.btTlUIion/fiution, and the ambient \u.ch pcoceu r~ived pos/tiY8 ranklno, ~ the flue dust or
,...;dual materiall win be atabIIized/fixed usJng . standard, ~n technology, and bIcauM the sta.bI1izedJfix~ rnat8rIaJ ~I not
..CHd TaP regulatofy EmItL A6c8ment of ~eated materia18 in . cSnIgned repolltoty under aIIemaw.. 4, 5 and 6 ~
additional uauran08 of long "'"' eflec:tiwnna and permanence.
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Mr. Charles Coleman
Mr. Duane Robertson
A. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991
Page 11
~;~i~~i;~~iv~~;~:e~r;~:rii:~rDa~iVeS under tbe s~ort-
55 Fed. Reg. 8725 (March 8, 1990) (emphasis added.)
stabilization/fixation and onsite disposal were the only
alternatives that received a positive ranking for both short-term
effectiveness and implementability. The Cashman Process and the
ambient acid leach process alternatives, on the other hand,
received negative rankings for short-term effectiveness and
implementability. Both of these alternatives would take
substantially more time to complete and would have greater short-
term impacts on human health and the environment than the
stabilization/fixation alte~native. The Cashman Process also
received a negative ranking for cost. As discussed above, the cost
ranking for the ambient leach process will be revised to a neutral
ranking to reflect the large variability and uncertainty in the net
present worth estimate. Thus, in terms of balancing of. tradeoffs
among alternatives under the five balancing criteria,
stabilization/fixation strongly prevails. . Additionally,
stabilization/fixation satisfies the statutory preference for
treatment. Finally, EPA expressly states in the NCP that it must
take into account the implementability of the remedy in the
determination of practicability under the section 121(b) mandate.
See 55 Fed. Reg. 8727 and 8729. As discussed above and in the FS,
both the Cashman Process and the ambient acid leach process raise
serious implementability concerns. Implementability concerns are
nearly absent for stabilization/fixation.
Finally, it should be noted that the mandate in section 121(b)
of CERCLA ~o select a treatment technology g[ resource recovery
technology to the maximum extent practicable is stated in the
disjunctive; either a treatment technology ~ a resource recovery
technology can satisfy this mandate. There is no Dreference under
~ERCLA or the NCP for resource recoverY over treatment.
D.
The NCP's Preference for Treatment and Bias Against
Off-site Land Disposal of Untreated Waste.
v
Aside from the five balancing criteria, the balancing process
nahall also consider the pref~rence for treatment as a principal
element and the bias against off-site land disposal of untreated
waste." 40 eFR S 300.430(f) (1) (ii) (E). As discussed above,
stabilization/fixation is a treatment alternative and does not
involve off-site land disposal of untreated waste. Thus the
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Hr. Charles Coleman
Hr. Duane Robertson
"-. Lensink, Esq.
Laura Bassein, Esq.
May 22, 1991
Page 1.2
preference and bias cited above further support the selection of
stabilization/fixation as the preferred remedial alternative.
IV.
Net Rankina of Alternatives.
As illustrated by the above discussions, stabilization/
fixation received the highest net ranking under the threshoJd and
balancing criteria with a total of 5 positive rankings. The onsite
disposal and ambient acid leach process alternatives received the
next highest net rankings with a total of 2 positive rankings
(assuming the cost ranking for ambient. acid leach is revised to a
neutral ranking). Those alternatives, however, are plagued by
several serious problems, discussed above and in the FS. Each
other alternative received a negative net ranking. See Comparative
Analysis Table.
:In addition to having the highest net ranking under the
threshold and balancing criteria, stabilization/fixation also (1)
is the most cost-effective al.ternative, (2) fully satisfies the
directive to utilize permanent-solutions and alternative treatment
or resource recovery technologies to the maximum extent
practicable, and (3) meets the NCP's explicit preference for
treatment alternatives. Finally, remedial activities under the
stabilization/fixation alternative would be consistent with the
remediation efforts for the remaining operable units at the Smelter
Hill site. stabilization/fixation is the clear choice for the
preferred alternative to be included in the proposed plan.
If you have any questions concerning this analysis, please do
not hesitate to call. ARCO .r.espectfully requests that EPA
carefully consider this analysis in preparing the proposed plan.
please include this letter in the administrative record for the
Flue Dust Operable Unit.
-Z2;~/~0
Sandra M. stash, P.E.
Montana superfund Manager
SMS: j b '.
Attachments
cc:
Robert W. Lawrence, Esq.
Pamela S. Sbar, Esq.
-------
'rABLB 10.3-'
la41.1du.l E.aluatloo of Final Alternative.
Alte~oatlve. 1 Through t
ALTIRH~TIVE 4
ALTERHATIVB 1 ALTERHATIVE 2 ALTERNATIVE] 8TABILIUTION!
CRITERIA N') ACTION OHSITE DISPOSAL OFFSITS DISpOSAL fIXATION
--
OVERALL Doee n~t ~~ovlde p~otectlon of human protection of hu.an proteotion of human
I'POTKCTIVENESS .~uquete ~rotectlon h.alth and t.he "..ILh and t.h. healt.h and t.he
of human he.lth and environment achieved environment achieved environment. achieved
the environment. l.IuroU9h plaoement. of th~ough plaoement of through production of
Flue Duat In a RCRA Flu. Dual In a a atabl. non-
subtltle C permitted RCRA TaD oharaoterletl0
repo81tory. facUlty. .ater 1& 1 Ind
i placement In In
en91n..red
repo.ltory. j
COHPLIANCB WITH AMI'S Would not attain Would attaln ARAR.. Would attain ARARa. Would attain AllAR..
, ARAR..
i
LONO-TERK Existing rl.k would Risk of contaminAnt Risk of contaminant Rllk of contaminant
EFFECTIVENESS AND remain and .ay r.ie..e. effectlvely relea.e. effectively r818..8 .ffecllvely
I PEIUtANINCB lncre.... reduoed, but. wlll ba reduced, but will be reduced, but will be
dependent on 10ng- dopendent on 10ng- dependent on the
term h.tegrlty, term Integrity, long-ter~ atabllity
maintenance and maintenance and of traated ~aterl.l,
monitoring of a RCRA ~nltorlng of . RCRA .~d long-term
, '1J Subtitle C TSD faoUlty. Integdty,
08 ~epo.ltory. ' . .aintenance and
monltorlng of an
:D:D anglneared
repoeltory.
:
cao
zC:
»>
.-C
-I
-<
"
-------
::)
c
TABLS 10.3-' (COQtlDue4)
AL"l'BaNATIW ,
< ALTSIIHA'Uva 1 AL'l'ERHATIVB 2 ALTERHATIVB , 8TUILIUTIOH
CRITEllI A HO AC'rIOH OHBITS DIBPOSAL OFF&ITB DI6P08AL PIUTIOH
~DUCTIO" or Ho reduotlon in Ho reduction 1n Ho ..eductIon 1n Reduotlon of toxlc1ty
JXICITY, HOBILITY, toxLcity, eobl11ty, to.lolty, moblllty, to.lolty, moyLl.lty, and ~blllty to balow
R VOLUHB THROUGH 01' volume. 01' volume through OL volue~ tbwough nonoharaotarlatlo
R8ATK&NT treatl\ant. treatment. (TCLP) layela.
Increa.e 01 yotu~ by
appro.l.ate.1v 15
percent..
.IIORT-TERK Hot applloab18. Duet controle Duet control. Duet contro\t.
;1"I'ECTI VENESS requIred to reduce requ1red to raduce requLred to r.duca
workor and communlt.y worker and community work.r and ~ommunlty
riBk. Two year rlak. J\ddltional rl.k. Add'tional
implementation. handlIng and trana- oanteol. r~qulr.d tor
portaUon would tr.at..nt. Thr.e
lncreae8 potentlal year Impl~~ntatlon.
. for re1ea.e. 81x
~nth implementat.lon.
I HPLEHENTABILITY Not app\1cabI8. Simple to conetruot Simple to operat.. sLapl. t~ canetruct,
and operate. Ho con.truct,ion .ome\(ha~ comple., but
6erv1ce., oqu 1 pnent SeryIcoa, equ1pment proyan, to op.rala lo
and t8chnoJ~9Y are and technology are lIIeet A((ARa. s.eyIc..
readily available. r.adily available. equl~nt and
. taohnolOO
-C
~»
--c
1:---
-------
~A8L8 10.3-' (oOD~lDued)
AL"r&RHA'fIV8 51 ALTERHATIVB 58 J.L'1'BUr.TIV1S ,
CA.HMAM PROCESS Cr.SUMAH PROCESS AMBIBNT ACID LEACR
CRITERI" WI'1'd 8'1'A8ILIIITIOH WI'I'IIOUT 6TABILUr.TIOH WITS ITABILIIr.TJOH
~RALL 'ROTECTIVENESS Protection of hu~.n health protection of human h.alth proteotlon of human health
and the .n.i~o~ental and the envlronment and the enyironment
achLe"ed tb~ough removal of achle"ed through removal of achie"ed through removal ot
.ome conte~lnante, aom. contamlnanta, .ome contamlnanta,
atabLll&atlon of realduea, production of a atabl. non- atab1ll~atlon of raalduaa,
and place..nt of non- characterL.tLc re.ldue, and and placement of non-
charaoterlat1C .aterLal 1n placement in an engLneered characterLatLO material 1n
an enaLneered"repOaltory. rep08Ltory. an engLne.rad reooaltory.
)HPLUHC& WITII ,.R,.R8 would atteln ,.P,.R8; , would attaln ARI\Pa. Would attain ,.RARa.
-
OHO-TERK EffECTIVENESS AND R1ak of conta.inant r.lea.e Ri8k of contaminant relea.. Rlak of conta.lnant rele.ae
ERHIHEHCB effectL¥81y reduced, but effectlvely reduced, but effeotively reduced, but.
wL11 be dependent on long- w1ll be dependent upon the wLll ba dependent on 10n9-
te~ atabl111ty of tre.ted ablllty to produce a long- ter8 integrlty, .alntenanca
",atec-lal, and long-ter. term atable non- and ~nltorlng of an
lntegrlty, .alntenance and characterl.tLc ra.Ldue, and englneered repoaltory.
~nitcrlng of an engLneered the long-term integrity,
repoalto~y. maintenance, and monitorlng
'. of an englneered
repoaltocy.
la4l.idual a.aluatio..of rl.at Alter.ati.ea
Alter.atl.ea SA '1'brougb ,
-0
o
00
:IJ:D
-
(;)0
ZC
»,
r"
\' ..-
.08.
(::
y
-------
,-
ALnlUl"'tJVB 5" AL'l'EIUfA'l'IW 58 u:nUl,. 'l' I va ,
CA811MAH PftOCESe CAS8MAH PROCES8 WITDOut AMDI~Kr ACID I~ACB
Cftl'tEftlA WI'1'8 8'l'ABILISA'1'IOH &TA8ILIIATION WIT8 ITA.nlLUAT101f
<
IEDUCTION 0" ~.ductlon 01 ~o.lolty and ~eduction ot toxLcLty a~d Reductlon of toxicity
;OXICITY, HOBILITY, ~obLLlty ~o bel~ non- mobility, although pDe81bly not and ~obl1ity to below
IR VOLUHB THROUGH characte~l.~lo (TCL') le"el.. to below non-ch.r.cte~l.tlo non-character18tlc
rREA THEN'I' Inorea.e of volu" by I l.vel..
(TCLP) 18"e18. ~.duct~?n-rf (TeLP) Incre..e
appro.1..~elY 15'. volu.. by .PP'~o.l~at.~y 4~. of "olu" b{
approxllDat.ly 13\
,-
SHOR'I'-TERK Du.t control. ~equi~.d to reduce Duet control. requlred to reduce Du.t control. requlred
£ FFICC'I'lVENB88' worker and c08munl~y rl.k. worker and community rlok. to reduce worker and
control. al.o needed for control. al.o needed for cQGIIDunlty r18k.
treatment operation.. S8.en to treatment oporatione. Control. al.o needed for
. eight-yea~ i.pl...ntation. ~ppro.i~te Beven-y.ar tr.at~nt operation..
lcnplem.ntat1~n. s..an to eight-y.a,
llDp18lD8ntat1on.
JHPLEH£HT~BILITY Compl.X to conatruct and complex to con.truct and eoeple. to con.truct and
~perat.. 8~ .xotio' equipment operate. some exotic equipnent operate. 8.r,,1ce8,
n..ded. 'training of per.onnel needed. Train1ng of per.onnel equipment t.chnology are
required. Teohnology not pro"en required. Technology not proven avanable. Tra1ning of
at full eoal., e.oep~ for a~ full. .oa1e. par.onnel .ay b.
.tabillcation .~a9.. requlr8d. T8chnolo9Y
, . . pro"en 1n commerclal
. . operation..
I
I --
PRESENT WORTH C08'1' <,~"JD8NTJAL» «CONFIDENTIAL» $19,189,000
~T 10' DISCOUNT
ladl~ldual EyaluatioQ of rlaal Alteroatl...
Alt.~a.ti... 5A ~brou9b ,
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"'n&c~nQ.l, Mor-,tanl !971'
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F&CSlmlle ~;&3 a2&9
Kay 9, 1991
Mr. Charles Coleman
US Environmental Prote~ion
Region VIII
Montana Office
301 South Park, Drawer 10096
Helena, Montana 59629
Dear Charlie:
Agency
ARca has reviewed t~e economics of the treatment
alternatives included in the flue dust RI/FS. Based on
this revie'", a sensi ti vi ty analysis ?f the net present
value costs of three of the alternat1ves was performed.
The accompanying Tables 1 and 2 summarize the sensitivity
analysis of the net costs of three processing
alternatives included in the Anaconda Smelter Site - Flue
Dust Operable Unit Re:1edial Investigation/Feasibility
Study. These alternatives are the Cashman, Acid Leach,
and Stabilization/Fixation processes. The variables
evaluated were those with significant economic impact,
and also characterized by substantial uncertainty. They
include the capital cos~s for the ,construction of the
processing plant and residue repository, plant operating
costs, repository operating costs, and the price of
copper and any associated r~venue. For each alternative,
these variables we:'e ass1gned an "expected" cost or
price, and a "best" and "worst" case value. In this way,
a range of net present value cost ~as computed for each
of the three technical processes. Note the "expected"
f ic;ures are those taken trom the RIfFS, arid represent the
work of Dames and Hoore: and the "best" and "worst" cases
are the lowest and highest projected .costs (and biqhest
and lowest prices for recovered copper) respectively.
Table 1 shows all t.'1e aportant variables and their
projected values, and Table 2 summarizE's the sensitivity
analysis results.
CASHMAN PROCESS. The Cashman Process was evaluated for
t."o process variations for each scenario. These are
designated in Table 1 as: (A) stabilization of 'the
process residue wit.~ subsequent placement of the
stabilized material in a repository: and (B) placement of
the process residue in a repository without additional
treatment. The first option would be required only it
the residue did not pass TCLP toxicity tests.
ATTACHMENT C
-------
Mr. Charles Coleman
Kay 9, 1991
Page 2
The expected capital cost tor plant const--uction for the
Casmnan Process is $43.7 million. This tigure was
provided by Dames and Hoore in the RIfFS. The CUI10unt
assumes all new equipment. Thus some savings might
resul t trom the use of used apparatus. Even so we
believe the best case scenario would still require
capi tal costs no less than 20 percent lower, or about $35
million. For the wors~ case scenario these capital costs
are assumed to be 35 percent higher or $60 million,
because each more detailed study of plant costs that has
occurred has shown these costs to be substantially
increased from the preceding one, and because of the
absence of an historical record of actual costs for such
a facility. .
Plant ope:-ating costs for the Cashman process include
large amounts tor labor, fuel, power and water, and
reagent charges. We believe it is unlikely that all of
these cos~s would decrease at the seme time and therefore
the best case scenario maintains. the expected costs.
Although such costs may be expected to rise, all are not
expected to rise at the SaJDe time and therefore the worst
case scenario includes only a 10 percent increase over
the expected amount.
Reposi tory operating costs would vary widely depending on
. the toxicity ot the process residue and the need for
. addi tional trea'bnent of this material. As further.
trea tment is required additional costs will be incurred.
This is. reflected in the analysis through consideration
ot Cashman alternatives both with (A) and without (D)
stabilization. In both cases the important repository
operatinq costs are equipment rental rates and fuel
prices. Equipment. rental rates are not expected to
decrease and anticipated stable oil prices may minimize
tb.e chanqes in fuel costs. Therefore the same rationale
used in estimating best and worst case scenarios for
plant. ope~atinq costs ,explained above was also empl~yed
for repos:.tory ope:atl.ng costs. . .
Copper and certain other metals will be recovered in the
Ca~~~an p:-ocess. Within the last 10 years copper has
..- "'ie.' in tccay's prices between $.70 per pound and $1. SO
,..: These are the prices used in the worst and
:::= ~cenarios respectively. Also, in the worst
.;.:... .,;:.:::nario, the revenue is lowered further by assuming
t)
i
POOR QUAL'TY
OR'G'NAL
-------
Mr. Charles Coleman
Hay 9, 1991
Page J
L
that only copper can be sold and that the other metal-
bearin9 ~roducts must be disposed. The best case
scenar10 1ncludes revenue for all metal-bearing products.
ACID LEACH. The Acid Leach process results in a toxic
residue and all such material must be stabilized and
placed in a repository.
The estimated capital costs for construction of an acid
leach facility have not been evaluated as thoroughly as
were the costs for a Cashman Process plant. Because of
this, caDi tal costs under the best case scenario were
taken to- be only 10 percent less than the expected
amount, whereas, in t.'le worst cas e scenar io, capital
costs were increased by 50 percent.
The expectations for operating costs followed those for
the Cashman Process. Na.mely, costs in the best case
scenario were not decreased from the expected costs, and
in the worst case even't., costs were increased by 10
percent. .
The range in copper prices used is the sa.me as for tbe
Cashman Process. Note that only copper is recovered
using the acid leach method. All other metal is disposed
in the stabilized residue.
STABILIZATION/FIXATION. This process mixes cement and
other additives with the flue dust to make a stable
concrete and is qui te similar to the methods used for
producing structural concrete. The
stabilization/fixation technology is therefore well known
and the uncertainties of the cost parcmeters are small.
In the evaluation of this alt:ernative in the RIfFS, it is
assumed an outside cont=actor would be used to provide
the batc~ plant and the operating personnel. This
;-esul ts in no construction ca~i tal costs, and s~nce metal
1S not recovered, the prlce of co~per 1S not' a
consideration. Thus the econotUc evaluation is based on
operating costs that would arise over a three year
period. Because the method for making concrete is well
known and the price of the addi ti ves have been rather
stable we are suggeSting that the best and worst case
scenarios should vary f=om the expected aJ:1ount by only 10
percent and 20 percent, respectively.
-------
Hr. Charles Coleman
May 9, 1991
Page 4
I
NET PRESENT VALUE ANALYSIS. As smmft~1"ized in Table 2,
from best to worst case, the Cashman Process NPVl.O varies
by a factor of more than four, ranging from a low of
negative $18.7 million to a high of negative $88.4
million. This high degree of variability is a result of
the relatively high capital cost, and the uncertainty of
such costs because a Cashman Process plant has never been
built: by the wide range in copper price and the
uncertainty regarding the marketability of all metal-
bearing products: and due to the fact stabilization of
the residue may be .required. Note t..'le exceptionally high
capital construction and ODerating costs cannot be offset
by the revenue, even under the best case scenario. This
results in the best case Cashman Process NPV10 being
approxi:ma tely the same as t..~e NPV 10 of. the expected (C?r
possibly even the worst case) scenar1.OS for the aC1.d
leach and the stabilization/fixation alternatives.
However, .in the worst case, Cashman net present value
costs ax:e very much higher than any anticipated costs for
the other two alternatives. See Table 2.
The degree of variation of the NPVl.O from the best to.
worst case for the acid leach alternative is even larger
than that for the Cashman Process, almost a factor of
six. This reflects t..."1e relatively large uncertainty
regarding the capital const:uction costs and potential
variability in the future price of copper. However, the
absolute range in dollars of the NPViO for the acid leach
alternative is much less than the Cashman Process and in
fact in all cases, the best, expected and worst, the
Ni'V&o figures are much better than those for the Cashman
alternative.
On the other hand, compared wi th the
stabilization/fixation technoloqy, the acid' leach is
lower cost in the best case, but 50 percent higher cost
in the worst case. Al though acid leach and
stabilization/fixation have comparable expected costs,
acid leach exhibits much more unce~ainty in its upper
and lower ranges.
The stabilization/fixation alternative shows the least
variation in NPV'OI. indicating that the process
parameters are well kno~. AI though NPV 1.0 f or the best
scenario in the stabilization/fixation alternative is
greater than that for the acid leach method, the worst
-------
Kr. Charles Coleman
Kay 9, 1991
Page 5
.0
case scenario for the acid leach is approx.iJ:lately one and
one-half times that ot the stabilization/fixation. As
shown in the tables, the eXi'ected costs of these two
al terna ti ves are comparabl e .
The NPV10 costs are smmnarized for all three processes in
Table 2.
Yours truly,
~~ ~ ~\~\..jl
san~. Stash, P.~
Montana Superfund Manager
SMS/mk
cc.:
P. S. Sbar, Esq.
R. W. Lawrence, Esq.
"
-------
Table 1
Flue Dust processinq Alternatives
sensitivity AnGlysis
(million dollars, except whert1 indicated)
c....-. ......... a.l. L680h ......nl..~I_'''.-U-
aut. ."'.I!"'" 1IDEH ..... '~d'" IIIW\1 88G ,~P-t8d. ~
. . a 8 a 0
..-..-~I- ao.. ao.. ea.. ea.' e... ".0 la.o a..' 82.0 .a.o .0.1 ao.o
. 'I C88...--U- e.8 4.:1 4.. e.a 4.8 4.:1 ..:1 4.:1 ..:1 I_A. "'A. .aaa.
''''.''' '0.. '0.. '0.. a... ".0 11.0 e.. 4.8 e..
". Clp88"8U.. a.' 0.0 a.' e.. e.' ... S.. S.. e.s
~.- .... ~. ,'.0. 'a... la... 0'... '..'0 ,..,. I'... ,a... ,..,.
'e.e .e.. 11.0 a..o o.e 0.. a..' '.8 ..0
- ,-.. , I'.' 1'.0 81.' .,.. ao.o 10.. e.' t.e 11.0 t.' 0.. ao..
,.... 8 8'.8 a'.8 ...1 ..., 1..8 1..8 ao.' 11.8 18.8 t.t e.e ao.o
,.... . t.t ..e 10.8
J C.., U.I n.- U.I n.' It.' al.' .., a.a a.'
.f)
II.. al.e 18.. a... ... a.e '0.' t.a 0.0
I.')
~., I.. ... ca..' e.. ca...' (,.a, a.. ca..) ca..'
(8'.0' uo.') Co.... C-.II C...e, Ct..4' C.." ca..:I) C JO." ca.." ca,..' Cu..)
. .
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Table 2
NET PRESENT VALUE COST AT 10' DISCOUNT
Expected
Best css. (Pames & Mooro.) Worst Cas.
hman process $27.8 million 50.2 million 88.4 million
ith stabilization)
.hman 18.7 million 40.1 million' 78.4 1\111ion
,lthout stabilization)
,d Leach 6.5 8illion 21.7 million 34.7 million
abillzation 19.1 million 21.9 million 24.9 million
. . .
-u
08
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. Calculated by authors for this report
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April 29. 1991
MdrM Lensink. Esq.
Office of Regional ColnSel
U.S. EnvironmentaJ protection Agenr:t
One Denver Place. 999 18th S1reet
South Tower. 7th Floor
Denver. Colonldo 80202
RE: EVAlUAT10N OF INNOVATIVE AND RESOURCE RECOVERY
TECHNOLOGIES UNDER CERCLA AND THE NCP FOR THE FLUe DUST
OPERABLE UNIT
Dear Andy:
This letter 8ddr~'es two questions pertinent to the evaluation and selection of
remedial altemaUves for 1M Flue Dust Operable Unit at tn8 Anaconda Smelt8r S1te.
First. should innovative technologies be given preference over conventional technologies
during the remed1af alternative evaJuatton and remedy selection process? Second. tPw
does the statJtOry directive In Sedion 121(b} of CERCLA that EPA select a ren1ttdlu
action that utilizes permanent solutions and alternative treatment ~nologies or
resource rea:Nery teehnologies to h maxflT'Um extent practicable. Interrelate with the
nine criteria for evaluation of remediaJ alternatives set forth in 40 CFR i 3OO.430(e)(9)Qt1)
rnine remedy evaluation criteria'. .
1.
~
Innovattve technologies should not be gtven 81Tf &pedal pr8ference under
CERCLA or the NCP during the detailed analysis of aJtemstfves In the feesbiJiiy 81udy
cr during selection gf t\e remedy.
CERCLA', mandate to aeled 8 remedy that utiflzes resource recovery
technolOGies to 1he maxJmum extent practicable must be addressed through the
evaluation of alternattves under the nine remedy evaJua1ion criteria. No seperate
aiterion exIsts for determining 1hat a remedy utilizes resource f«;OVery tect1nologles
\0 1nG m;ximu,m ex10nt pra...~I9.
"
ATTACHMENT D
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Apnl 29, 1991
Page 2
IL
~
A.
Innovattve Technolocie$
Imaatfve technologies should net bQ given at1Y spedal ~rence c1Jring the
detailed analysis of attema1Nea in 1he feasibiOty StUdy ("FS, or in remedy celedon. 1n
the Na1icnal Contingency ~an rNCP"'). EPA does encourage the developmant and
consioeration of Innovative taChnology aJtematives. Hcwever. EPA m;kes doar In the
NCP and elseWhere that in sel~ng a final remedy, I!! aJternativeS must be evaluated
under the nine remedy evaluation criteria. ~ee 40 CFR i3Q0.430(o)(9)(nij ("Nine afterta
for ewluation"): 40 CFR S300.430(f}(1)(i) ("Selection of remedt)("The {nine) criteria
noted in paragraph (e)(9)Qii) of this sac:tion are use~ to seled a remedy.'. EPA
Qxplains tne evaluation and selection process as foUows:
A detaDed analySis shall be conduc1ed on the . nmlted number 01
atternatives that represent viable approaches to remedial action after
evaluation in the screening S'tage._.'The deta.Ued analysis consists of an
lS$G"ment of InClViduaJ aJternatjvQs against each of nine evaluation critsfia
and a comparative analysis that ~es upon the relative performance of
each ;fta(natNe against those aiteria.
40 CFR I 3OO.430(e)(9)(1)etailed analySis cI aJt!maUvesj.
EPA also discusses the tr9attnent of InnoV1!1iYe technology in 40 CFR f 300~
('Remedial Investigation/feasiblfrty study and selection of remedf).' Nowhere In 1hose
dlsaJssions does EPA gve Ir1novatN8 18ChnOIogy attamat1v88 8 preference In the
remed't. leledion process. The first mention of 1nnovative technclogy is found in EP A'.
Oat of ~ons for developtr.g 8PJX'CPriat8 remedial alternaUves:
EPA expects to consider U5ing movawe technology when su::h
technology o1fers the potential fer comparable or superior 1r82tIMnt
performance or 1mpfementabBity. fewer or lesser adverse inpect:s than
other avanable approaches, or lower costs fer simftar levels of performance
than demonstratBd tschnologies. . .
40 CFR 1300.430(a)(1)(iiij(E)C'~ona').
.. ...
. ..:
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Mr. Andrew Lensink
April 29. 1991
Page 3
Three things rrAJ!t be undr;1 ,tood about this t:xp&Ct8tfon. First. .[EPA's]
expectations are net ... binding requtrementS.. 55 Fed. Reg. .8702 (March 8, ,~).
Second: .
The fa':t tNt a propcsed remedy may be comimnt wtth the expectations
does net ccnstitute ~ificiQnt grounds for the selection of that remed1al
Bttemative. AIJ remedy selections rrAJSt be baSGd on an analysiS using the
nine criteria.
. }2. And third. the expect2tion by it3 terms limits considera1lon. of innovative.
teclmciogies to cases in which the innovative te~olcgy "offers (1) u'e poten1iaJ for
comparable or superior treatment performance or implementabnity, [2] fewer or lesser
adverse impacts than ether available approaches, or (3] lower costs for slmBar Iev~
of performancs than demonstrated tec::nnologiaso.. oW CFR S300.430(a)(1)(i~(E)
\EXpectations").
In sum. whDe the expectatIon cited above ~dencGS EPA's i'Itent to 8ncoc.n1ge
ccnsidefcmcn of Imovative tecl1nclogy alternatives. It i1 does nat alter the rule that
alternatives must be jvdged based upon the n~ ~edy 8vruuation crtteria.
The next reference to innovattve technology In 40 CFR S 300.430 is as ~!ows:
. The lead agency shal1 develop one or more Innovative trea1ment
tGlchnologi9$ for further consideration If 1hcse technologies offer the
potential for comparable or superior perlormance or Implementabi1ity:
fewer or lesser ad~. i'npacts than other avaiJabie approaches; or lower
ccstI for 8imIar levels of perforTr\ll1Oe than demonstrated treatlilent
technologi81. .
~ CFR ~.430(e)(5) rFeasibB1ty study'1. This P«MsJon per1alns only to the
development of remEcdiaJ alternatives prier to 8a'eeni1g, and 1hen. only to those
movative technologies that offer sim1ar or superior advantages as compared with 01hGr
aAemzmve5.
It lsa1so rnpcrtant to understand 1t',e commar:ts on the proposed NCP'that led
to this prevision. As EPA explaIned in ti'\e pr~bl8 to the NCP, .ccrrunenta10r3 !'ta1ed
that the proposed approach for the development End Ia'Mnlng of aJtems1ivC$ is biased
against Innovative technologies.. 65 Fed. Reg. 8714. (March 8. 1990). EPA thus
sought ~ d~ that It does not intend to Inhibit 1he doveloprnent of hnovdv8
technologies - [and so] de{etQd the requirement in the final rule 1hat innovative
-------
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Mr. Al'drew l.ensink
April 29, 1991
Page 4
technologies must offer 'better' performance than prcven technologies.. ~. In short.
Uke 1ha ~tion cited earflSr, thiS prov:sion was designed to put Innovative
technologies on equal footing with other a./tema1iveS, not elevate their status.
A third means by wt->Jcn EPA saeks to provide equal treabTl8nt for inncvative
technologies Is through the use of treatability studies. EPA recognizes 1hat "becaUSe
of the limited data on innovative technolOQies, It may not be possible to evaluate these
process OpU0n5 on 1he same buis as other demomttated t8Chnologles.. Guidance
for Conduc:1ing Remedial Investigations and Feasjt)iT'rty Stuales Under CERCLA. OSWER
Directive 9355.3-01 ("Guid~") at 4-18. EPA th~ .emphasizes the need for
perlorming tr&atability stUdies eartler il tne remedial process.. 55 Fed. Reg. 8714
(March 8, , 990). ~ ~ 40 CFR S300.~(d)(1) "RemediaJ investig~on1rro
characterize the site, the lead agency shaJl, as appropriate, conduct field investigations,
~cludlng trBatacnlty StUdJI!:S..!). .
After treatabnlty studies are comple1ed, "[t]he results of bench end piJot tests
[conducted during the stud~] can be ~d to ensure that conventional and InnOYattve
technologies can be ,wtyated equanv witn non.trea1ment alternatives during 1he
d9taJted ~sjs phase of the FS.. Guidance at 5-11 1tTough 5-12 (emphasis added).
AQain. the goal i3 equal, not preferential, trBOtment tor i"lnovative technOlogies.
The only point at which innovative technologie3 may be said to receive favored
trezstment Is during the 88!ti $CfHning stage. EPA has stated ~ 'mnovatNe
technol~ies woutd normally beceni6d through the sO'eGning phrase It there WQI'8
reason to believe that the inn0vatN8 technology would offer signmcat'lt edvantages..
Guidance at 4-26. ThIs makes sense, because at the screening stage an nnavatNe
technology mi~ be o~advantaged by 1M lack of opponunity to conduct a treatability
study. Ant advantage given 10 innovm!w technoIogiet. however, d"9Ppeal'S once the
Initial screening stage Is over. N.!he au1horitles c!t8d above make Cllar. during the
detaned analysis phase aD aJtematN.. fTLISt be evaluated e
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Mr. Ar.drew Len~ink
Apnl 29, 1991
Page 5
criterion addresses the atatutcry preference for &efec1!ng remediaJ actions that employ
treatment technologies -.,. No such prQferQnce exms for ~ativ8 technologies.
An EPA Memorandum dealing with the subject 01 nnovattve technofogfes
supportsths above analysis. ~ generallv Memorandum Re: Advancing U1e Use of
Treatmont Technologies for Superfund Remed"leS. OSWER Directive 9355.0-26
rMemorandum,{February 21. 1989). There, EPA (1) dlsaJsses its intent to eocourege
the use of Innovative tecrnologies tMt offer potential benefits over conventionat
technologies; (2) states that InnovatN8 technologies would bo carried through the
technology Icresnlng phasej and (3) encourages the use of trestabiBty studies. !g. pp.
2. 4. Again, however, EPA reiterates In the Memorandum that during the final sel&ction
process, 8[t]he 1nn0vativ8 technology should provide advantages similar to those
pC'a.nded by other technologies ovaJumed, with respect to the nine evaluation criteria."
}d. at p. 4.
In sum. whOe EPA has stated Its desire to encoLrage consideration of imovative
1ectmology alternatives, It doet not mend by that encouragement to sacrifice in any
way the larger 90al of choosing the remedy that best mee1s the ntne remedy evaluation
criteria. .
D.
Resource Reccrterv AJtem~
Section 121 (b)(1) of CERCLA provides:
The President shan SQlect a remed1aJ adion 1hat Is protective of human
health and the environment. that Is cost effedM, and that UtilIzes -
permanent solutions and 8ftemative treatment t&chnologle$ or resource
recovery technologfes to 1n8 m8:1dnun 8Xtent practicable.
. ,
~.; ..2 U.S.C. S 9621 (b). The attfcaJ ques1Ion for our purpotM Is hOw 118 mandtrte to
select remeclaJ action that utlTlZeS resource recovery technologies to the maximum
extent practicable relates to the detailed e..'1aJys1s of alt8m8tives under the nine remedy
evaluation ~rIa. The NCP direcUy addresses this question:
Each remed'saJ actiOn shall utilize permanent solutions and alternative
treatment tec.'v:ologfes or ~rce re:cvery technologIes to the maxImum
extent practfcable.' . 8 nt h~a tfiD .
sftematjve th8t satfs1lec oaracraoh (f)(1ll1ilCA' and (aLm.Jbis ~
Irelatina to 1he "threshol~ criteria" of j)~n of human hea~
, environment and a11alQjno' A_n~ trade-
.~
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Apnl 29. 1991
Page 6
~ amonq altema1htes in terms of the 1tve ortmarv balancing criteria not~
In oaracr:~h ff)(11ffiCB1 of th" s~QQ..j10n0.{erm effectNeness and
oerm~en~;: r~~oo of tori::itv. moQ!ntv or volume ~OUQh treatment.
;hort~rm ;~~e8S; ~lememabj[rtv: and cos1L..IhUmJancing s~
emch~!iz9 loncHerm ~V'"Jness and~ction of toxicity. mobIl!tv or
v~l~me thr~~~h treatment. 1)18 baJanctng shaLl!so consger the
pr;;ferencs for treatmern as a olinde!1 element and the bias aoelnst off.
;1t; iand dISOOS~ of untreated waste. 10 makinq the determination under
~is ;aragraQ~ modttvina criteria of state accec1ance and communttv
ecceetance -' shan also be considered.
40 CFR S 3oa.430(t)(1)(i~(E)("SelectiQn of remedyj.
In sho~ the NCP provides that CERCLA's mandate to select a remedy that
utilizes resour~ recovery technologies to 1he maximum extent practicable must be
addressed through the nine remedy evaiuatJon criteria. No separate aterion exjsts for
determining that a remedy utilizas rBSource rea:NafY technOlogies to the maximum
extent practicable. Rather, EPA evah.ate, whe1her a 'remedy is protedfve and ahains.
AP~, and prov;des the best baJance of trade-offs among aftematNeS in terms of the
fiye ortmarv baJanclno criteria. .
The preamble to the NCP verifies that CERC~'s ctahJtory mandates are
re1lected In the nine remedy evafuation criteria and de not require a separate analysis
beyond- an evaluation of the alternatives in terms of sucn crtteria. EPA states exp6dtfy
in the preamble that
EPA developed the nine eva!\Jation criteria to give effect to 1he numerous
ctatutcry mandates of 8eCtion 121.... EPA is net adding as. attarion the
~tatutory mandate to UtlTIZ8 permar.8nt solutions and alternative trutment
technologies or resource technologies 10 the maximum extent practicable.
The anaJysis performed plJt'S1Jant to 1M nine criteria concludes with
&€Iadon of . remedy that m~ the statutory ma.rJ:jates.
55 Fed. Reg. 8719 (March 8. 1990). The preamble further explains:
AJthcugh generaJ1y supporting the uie of the nine criteria In remedy
selection, several Ctlmmentators expressed concern over wh81her the
balancir.g process ensures salect10n of remedies that ccmply v.ith the'.
statutory mandatae of CERCLA. In response. EPA befieves that 1he
, remedy aeledion ~s promulgated today effodvely h=umontzes the
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April 29. 1991
Page 7
soma~t competing requirements of CERCLA and ensuru that remedial
actions wii futfiU each statutofy mandate.
55 Fed. Reg. (March 8. 1990).'
In fact. EPA specificaJly rejec:t9d a proposal that the statutory mandate in section
121 of CERCLA be made a aiterion for detailed Malysis of rem~laI aJtBrru:1ives:
Several commentators eddr=sed spodficaJly the statutory mandate tc
utilize p2rmanent solutions and aJtemative traatment technologies or
resourca recovery technologies to the maximum extent practJc8ble. One
commentator suggested estabnshing this statUtory mandate as a UTeshold
criterion.
, The preamble to lhe NCP contains the foDowing addltJonallanguage SUpporting
the conclusion that the $ta:lJtory mandata to select. remedy that utDlZes resource
recr:Nery technology to the maximum extent practi~le is met through evaJUKtion of
remedial altematives under the nino remedy evaJu.atjon crit8ria:
, /
The determInation of which altemattve Utilizes permanent solutions and
alternative treatment technologies to the mexfmum extent practicable takes
into account [the factors ct) [1] long-term e1f9ctiv9ness and permanenC8;
[2] reduction of toxicity, mobiJlty, or volume 1hrough treatment: (3] short-
term effedfveness; [4] implementabBJty; (S] celt; [and) [6] S1at8 and
ccmmunfty acceptance [with each factor being one of the nine criteria
Usted In the Ncp].
55 Fed.. Reg. 872S (March 8. 1990). Additionally:
EPA notes that 1h1 finaf bafancIng by which the remedy Is eeleded
decides. from emcng protective, cost-i!tfactive aJtemmlves, 1M extern to
which pennanent solLnions and tTeatment are practicable fer the site.
EP A must select an a.'terna:M! providing the maximum permanenc8. arid
treatment pradr:able. EPA uses 1tIe b21ancing and mo
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Aprtt 29, 1eg1
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Lary D. Milner, CAT 1618
C. Floyd George, OAT 1m
'M1IJam R. Wiliams, Anaconda, MT
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May 20, 1991
Andy Lensink, Esq.
U.S. Environmental Protection
Agenf:l/, Region VIII
One Denver Place
999 18th Street, Suite 1300
Denver, Colorado 80202-24103
I
Laura Bassein, Esq.
Montana Dept. of Health and
Environmental Sciences
Bureau of Solid & Hazardous Wastes
836 Front St.
Helena, MT 59601
RE:
Initial Comments on Final Screening Document, Flue Dust Operable Unit,
Anaconda Smelter
, Dear Andy and Laura:
This letter' provides. ARCO's initial comments on the final .Screening and
Description of Potential Appficable or Relevant and Appropriate Requirements ("ARARs)
for the Aue Dust Operable Unit, Anaconda Smelter NPL Site, January 1991" f'Screenin~
Documentj prepared by EPA and the State of Montana. These comments are basec
on Section 121(d) of CERCLA, EPA's August 8, 1988, interim final guidance entitlec
"CERCLA Compliance With Other Laws," OSWER Directive 9234.1-01 (the "ComplianCi
With Other Laws Manual"), EPA's August 1989 guidance entitled "CERCLA Complianc'
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Andy Lensink. Esq.. Laura Bassein. Esq.
May 20. 1991 .
Page -2-
With Other Laws Manual: Part II. Clean Air Act and Other Environmental Statutes and
State Requirements.~ OSWER Directive 9234.1-02 (the "Compliance With Other Laws
Manual: Part 11". and the Final National Contingency plan. 40 C.F.R. Part 300, 55 Fed.
Reg. 8666 {"NCP',.
For the purpose of preparing these comments, we have relied primarily on the
Screening Document's text rather than its ARARs tables. Outing our review of the
Screening Document, we found that there was not complete correspondence between
the ARARs tables and the accompanying text regarding whether specific requirements
are ARARs. In particular, the discussion presented in Section 3.4 of the Screening
Document of whether RCRA Subtitle C requirements are applicable or relevant and
appropriate requirements for certain remedial alternatives did not correspond to the
.Summary of Screening Analysis of Federal ARARs" specified in Table 5.1. For
example, while p. 3-20 of the Screening Document states that "Subtitle C requirements
are not applicable" to Alternative 3 (On-Site Disposal of Untreated Flue Dust Materials),
Table 5-1 indicates that RCRA Subtitle C requirements are "A/RA: i.e.,
applicable/relevant and appropriate. for certain remedial alternatives, induding Altemative
3. Similarly, while p. 3-25 of the Screening Document states that EPA has not
determined whether treated flue dust associated with remedial alternatives 5-7 is
sufficiently similar to hazardous waste for RCRA requirements to be ARARs, Table 5-
1 indicates that RCRA Subtitle C requirements are NA/RA." ARCO is concerned that the
Agency's attempt to reduce the Screening Document's text to tables could result in
confusion regarding whether certain requirements are applicable or relevant and
appropriate. Therefore, ARCO requests that the final ARARs for the Flue Dust Operable
. Unit be presented as clearty as possible.
ARCO requests that the comments provided in this letter be considered by EP A
and the State in the development and identification of final ARARs for the Flue Dust
Operable Unit. It is ARCO's understanding that final ARARs for the Flue Dust Operable
Unit will be identified in the Record of Decision for the Flue Dust Operable Unit.
1.
Characterization of Flue Dust Materials as K064.
On page 2-13 of the Screening Document, EPA identifies flue dust sludges in the
Bradley and Iron Ponds as hazardous wastes because ''the sludge at the two pond
locations is categorizable as K064 waste.8
ARGO beneves that EPA has incorrectly characterized the regulatory status 01
K064 waste for the purpose of categorizing flue dust sludges as K064. K064 is not a
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"
Andy Lensink, Esq., Laura Bassein, Esq.
May.20, 1991
Page .3-
currently listed hazardous waste because EPA has not relisted K064 following the U.S.
Circuit Court of Appeals for the District of Columbia Circuit's ("D.C. Circuit'1 remand in
AMC v. EPA, 31 ERC 1935. On July 10, 1990, the D.C. Circuit remanded the listing of
K064 to EPA because EPA failed to adequately address in the record challenges to
EPA's data, offer discussion of its studies and explain why its decision to list K064 was
reasonable absent such studies.
On February 7, 1991, we contacted Ed Abrams of EPA's Office of Solid Waste,
Waste Identification Branch to discuss the current status of the K064 relisting. Mr.
Abrams indicated that EPA has not relisted K064. Further, he indicated that EPA
considers the relisting to be a low priority item given EPA's belief that the TCL?
characteristic is "likely to pick up" K064 type wastes. Mr. Abrams confirmed that K064
is not a currently listed waste. He was unable to estimate when EPA might relist K064.
Because EPA has not relisted K064, EPA should not characterize flue dust as
K064 for the. purposes of identifying ARARs for the Flue Dust Operable Unit. The K064
listing has not been promulgated. Under CERCLA, ARARs must be promulgated, i.e.
requirements of general applicability which are legally enforceable. See Preamble tc
NCP, 55 Fed. Reg. 8746. The K064 listing does not meet these requirements.
Even if EPA ultimately relists K064 under the same description utilized by EPJ
prior to the D.C. Circuit's remand, the flue dust sludges do not fall within the scope c
the K064 listing description because the flue dust sludges were not generated Jrom th{
same industrial process and are not the same type of wastes as identified in the K~
listing description.'
2.
~rements that are Wrtb.!nJ.he Scope of the Flue Dust Qperabl£
Unit Can be ARARs. .
, EPA's description of K064 in the September 13, 1988 Final Rule is as fonows: Acid pia
blowdown sluny/sludge, resulting from the thickening of blowdown sluny, is a waste stream generatE
at facilities where primary copper is smelted in a reverberatory furnace. The waste arises from the ac
plant, which constitutes the principal controller for removal of sulfur dioxide from furnace and conven
off gases. The blowdown slurry from the acid plant is often thickened and the bulk of the soli,
content recycled to the reverberatory furnace. The overfl~ from the thickener contains be
suspended and dissolved solids. The suspended solids are settled in surface impoundments al
recycted to the smelter, the dissolved solids are discharged with the surface impoundment eff1ue
often to a tailings pond. h is the thickened sluny, the settled suspended solids from the thickener. a
the sludges that form from the dissolved solids in the thickener overflow that are the subject of t:
listing.
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Andy Lensink, Esq., Laura Bassein, Esq.
May 20, 1991
Page -4-
In the Screening Document, EP A discusses the fimited nature of the Flue Dust
Operable Unit and states that final compliance with .air quality, ground and surface
water requirements will occur at the time of completion of remedial action on the.
Smelter Hill Operable Unit:
The scope of the remedy in this matter is limited, particularly
where compliance with ground and surface water
requirements and final compliance with air requirements is
concerned. For the most part, final compfiance with these
requirements will be expected to occur at the time 01
completion of remedial action on the Smelter Hill Operable
Unit. Though the expectation is that these requirements will
be implemented later, they are nevertheless identified in this
document as ARARs pertinent to the Aue Dust Operable
Unit. Screening Document, p. 1-2.
While ground and surface water and air requirements may be ARARs for the
Smelter Hill Operable Unit,. only those requirements that fall within the limited scope 01
the Flue Dust Operable Unit should be identified as ARARs for the Flue Dust Operable
Unit. For example, on page 3-6 of the Screening Document, EPA identifies the water
quality criteria specified in 40 C.F.R. Part 131 as relevant and appropriate to the Flue
Dust Operable Unit. IdentifYing these requirements as ARARs overlooks the limited
nature of the Aue Dust Operable Unit and the fact that groundwater remediation is not
an objective of the operable unit. Similarly, EPA has identified federal and state surface
. mining reclamation requirements as relevant and appropriate requirements for the Flue
Dust Operable Unit. Reclamation activities contemplated by these requirements are
outside the scope of the Aue Dust Operable Unit and should be addressed in a
subsequent operable unit of the Anaconda Smelter Site. EP A should revise its ARARs
list to identify only those requirements that fall within the limited scope of the tlue Dust
Operable Unit.
3.
OSHA Reauirements Are Not ARARs.
The last sentence on page 3-12 of the Screening Document states "Therefore.
the OSHA standards are not applicable to the Flue Dust Operable Unit, but are
designated as applicable.8
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Andy Lensink, Esq., Laura Bassein, Esq.
May 20, 1991
Page -5-
The Preamble to the NCP clearly states that OSHA requirements are not ARARs.
(T]here are two principal reasons for theJreatment of OSHA
standards as non-ARARs in the NCP. First,... Congress
appears to have intended that certain OSHA standards apply
directly to all CERCLA response actions. Second, EPA
believes that OSHA is more properly viewed as an employee
protection law rather than an "environmental" law, and thus
the process in CERCLA 121 (d) for the attainment or waiver
of ARARs would not apply to OSHA standards. . .. Thus,
OSHA standards are no longer included on the list 01
potential ARARs. The Final NCP package (~ 300.150) has
been modified to reflect this approach, which EPA believes
is consistent with both OSHA and CERCLA. 55 Fed. Reg.
8679-80.
ARGO reiterates that it intends to comply with. applicable OSHA requirements a'
the Flue Dust Operable Unit.
4.
ARARs for Treated Flue Dust Residues.
In previous submittals, ARCO has provided EPA with information that certair
treated flue dust products, e.g., stabilization/fixation products, pass the TCU
characteristic test and are stable. EPA's discussion of RCRA as a source of potentic
ARARs for the Aue Dust Operable Unit overlooks this information. Stable treated flut
dust residues which pass TCLP are not sufficiently simnar to hazardous wastes fo
RCRA Subtitle C requirements to be relevant and appropriate requirements for tht
design of a repository for treated flue. dust residues that do not exceed TCU
regulatory limits. We believe that this position is consistent with 40 C.F.F
~ 3oo.4oo(g) (2) of the NCP. and the preamble discussion concerning when RCRA ma'
be relevant and appropriate for wastes similar to RCRA hazardous wastes. 55 Fee
Reg. 8763-8764.
ARCO recognizes that design requirements for an on-site repository for treate<
flue dust materials could include a leak detection system and groundwater monitorin!
wells, and has identified these design requirements as appropriate in the Preliminar
Draft RifFS. See, e.g.. p. 71. paragraph 1. The specific design requirements will b
determined in the remedial design phase and will be based on best engineerin
judgment. Certain design requirements may resemble design requirements in RCR
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Andy Lensink. Esq.. Laura Bassein. Esq.
May 20. 1991
Page -6-
Subtitle C. However, this does not make such RCRA Subtitle C requirements .relevant
and appropriate" as that term is defined in the NCP. Thus. ARCO believes that the
final ARARs determination for the Flue Dust Operable- Unit should clearly indicate that
RCRA Subtitle C requirements are not relevant and appropriate requirements for treated
flue dust residues.
5.
~acilitv Sitina Act.
ARCO disagrees with EPA's identification of the Major Facility Siting Act as an
ARAR for the Flue Dust Operable Unit. The Major Facility Siting Act applies to energy
generation or conversion facilities. The ARARs document notes that .no energy related
facility as defined by the law is anticipated for the Flue Dust Operable Unit areas.
However, the siting criteria are relevant and appropriate.. The document further states
on page 4-1' 6 that "although the ,act and its implementing regulations are not
applicable, they are relevant and appropriate. The act and regulations are intended to
prevent the siting of. major facilities with the potential to disrupt the environment or
cause damage to the environment from being located in environmentally sensitive
areas. These regulations address situations sufficiently similar to the removal action
and their use is well fitted to the site..
The Major Facility Siting Act. addresses large scale
geothermal/hydroelectrical/coal fired power plants and/or transmission lines. These
facilities are nothing like the on-site repository or the other remedial alternative which
may be constructed pursuant to the Rue Dust Operable Unit. Furthermore, none of
the sensitive areas and areas of concern identified pursuant to the act are similar to the
Flue Dust Operable Unit. For these reasons, ARCa requests that EPA delete the Major
Facility Siting Act from the list of potential ARARs for the Rue Dust Operable Unit.
6.
BQ.M..Land Disposal Restriction Reauirements.
. On Table 5.1 of the Screening Document, EPA identifies the land disposal
restrictions in 40 C.F.R. Part 268 as applicable or relevant and. appropriate
requirements for the Flue Dust Operable Unit.
The land disposal restrictions should not be potential ARARs for the Aue Dust
Operable Unit for several reasons.
"
EPA's "Policy for Superfund Compliance with RCM Land Disposal Restrictions,'
OSWER Directive 9347.1-02 (April 17, 1989) (the RLand Disposal Restrictions polie(:
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"
Andy Lensink, Esq., Laura Bassein, Esq.
May 20, 1991
Page -7-
reiterates and clarifies EPA's policy on the applicability of RCRA land disposal
restrictions to CERCLA cleanups set forth in the Compliance with Other Laws Manual,
pp. 2-18, 2-21 through 2-23. Under the Land Dispos?1 Restrictions Policy, RCRA land
disposal restrictions are only applicable to a CERCLA cleanup when three criteria are
met: 1) the CERCLA action constitutes placement (i.e., land disposal); 2) the CERCLA
waste is a RCRA hazardous waste; and 3) the RCRA hazardous waste is restricted
from land disposal at the time of placement. As discussed in previous submittals,
RCRA LORs should not be applicable to the Flue Dust Operable Unit because these
criteria for applicability of RCRA LORs are not met.
With respect to the first criterion, the NCP has deferred any final decision on
activities that constitute land disposal. Preamble to NCP, 55 Fed. Reg. 8762.
However, placement of flue dust or flue dust treatment residues in a repository on the
Anaconda Smelter Site would not constitute "land disposal- under any of the definitions
01 that term set 10rth in EPA's Supplemental Notice on the Applicability 01 the Land
Disposal Restrictions to CERCLA Actions 54 Fed. Reg. 41566 (October 10, 1989), the
Land Disposal Restrictions Policy, or ARCO's Comments on the October 10
Supplemental Notice that ARCO' submitted with its ARARs Scoping Document.
Furthermore, the Screening Document recognizes that RCRA requirements are not
applicable to remedial alternatives that contemplate on-site disposal of flue dust waste
materials within the existing contaminated area. 'While flue dust is hazardous waste,
Subtitle C requirements are not applicable to this alternative [on-site disposal 01
untreated flue dust], since there will be no treatment, storage or disposal outside the
existing contaminated are a.- Screening Document p. 3-20. Thus, the first criterion for
applicability of RCRA LDRs O.e., the CERCLA activity constitutes land disposaQ Is not
m~ .
. With respect to the third criterion, EPA considers wastes such as flue dust to be
-newly identified- wastes for purposes of establishing LDRs under S 3004{g) of RCRA.
55 Fed. Reg. 22520, 22530. EPA has stated that newly identified mineral processing
wastes are not subject to the BOAT standards promulgated for characteristic hazardous
wastes. 55 Fed. Reg. 22530. Instead, such wastes would be subject to further study
before BOAT is established for such wastes. 55 Fed. Reg. 22667. EPA has expressly
acknowledged that it "has not yet performed the technical analyses necessary to
determine if the treatment standards promulgated today as BDA T for EP toxic
hazarpous wastes can be achieved in treating the various mineral processing wastes.-
55 Fed. Reg. 22667. Furthermore, EPA recently confirmed this position in -Superfund
Guide to RCRA Management Requirements for Mineral Processing Wastes,- OSWER
No. 9347.3-12FS (November 1990). .
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Andy Lensink, Esq., Laura Bassein, Esq.
May 20, 1991
Page -8-
All mineral processing wastes that now are considered RCRA
hazardous wastes (Le., non-excluded mineral processing
wastes that are characteristic or listed) are considered to be
"newly identified" wastes and will not have treatment
standards under the land disposal restrictions (LDAs) until
EPA completes a separate LDR rule making. Furthermore, no
other LDR restrictions (e.g., soft hammer requirements,
California list requirements) apply to these newly identified
wastes.
Finally, ARCO notes that EP A has recognized in the Preamble to the NCP that,
EPA has determined that, until specific standards for soils
and debris are developed, current BDA T standards are
generally inappropriate or unachievable for soil and debris
from CERCLA response actions.
Preamble to the NCP, 55 Fed. Aeg. 8761.
7.
Current Waste Locations.
On page 3-16 of the Screening Document, EPA states that RCRA Subtitle C
. regulations would govern cleanup of the current waste locations, including the possible
stabirtzation and disposal of wastes in an on site repository. ARCO believes that EP A
should darify this statement to indicate that RCRA requirements are not applicable or
relevant and appropriate to the C\.irrent disposal locations, in part because the flue dust
at these locations was disposed of before the effective date of the RCRA requirements.
The Compnance with Other Laws Manual indicates that a necessary jurisdictionS:
prerequisite for RCRA applicability is disposal after the effective date of the pertinerr
RCRA regulations. See Compliance with Other Laws Manual, p.2-8. Furthermore, witt
respect to the cleanup of the current waste locations, EPA has defined. the scope 0
cleanups at the current 'v'vaste locations such that "adjacent soils containing equivalen
concentrations of flue dust contaminants will be excavated as well." EPA Comment:
on Prefiminary Draft RIfFS, p. 68, paragraph 3. Based upon the defined scope. of tM>
response action and EP A's position in the guidance document, the capital RC~
should not be an ARAR for the excavation of flue dust materials from their currer
location. .
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Andy Lensink, Esq., Laura Bassein, Esq.
May 20, 1991
Page .9-
ARCO appreciates the opportunity to present these comments on the Screening
Document. If you have any questions regarding these comments, please contact Bob
Lawrence or me.
Sincerely ,
GJCVY~ S ..JblJt-!ru.J--
Pamela S. Sbar
PSS/ mlh
C,,~~.Lm
c:
Sandra M. Stash, ARCO, Anaconda, MT
. 'Robert W. Lawrence, Parcel, Mauro, Hultin & Spaanstra, Denver, CO
Charlie Coleman, U. S. E. P. A., Helena, MT
Karen Zacheim, M. D. H. E. 5., Helena, MT
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ARCO COil Compo .,
555 Seventeenth Street
Denver. Colorado 80202
Telephone 303 293 4000
~~
~,
May 16,1990
VIA FEDERAL EXPRESS
Mr. Charles Coleman
Environmental Protection Agency
Region VIII, Montana Office
Federal Building
301 S. Park, Drawer 10096
Helena, Montana 59626-Q096
Thomas Eggert, Esq.
Legal Division
Montana Department of Health &
Environmental Sciences
Cogswell Building
Helena, Montana 59620
Mr. Duane Robertson
Solid and Hazardous Waste
Bureau
Montana State Department of
Health & Environmental Sciences
Cogswell Building, RM 8201
Helena, Montana 59620
Andrew Lensink, Esq.
U.S. Environmental Protection
Federal Building
301 S. Park
.
Helena, Montana 59626-0096
Gentlemen:
The purpose of this letter is to update the ARARs Seeping Document for the Flue
Dust Operable Unit (the .Scoping Document.) which the Atlantic Richfield Company
rARCOj submitted on August 31, 1989 pursuant to paragraph I)lA.6 of the Anaconda
Smelter Site RI/FS Consent Order, Docket No. CERCLA VIII-88-16. Since the Seeping
Document was submitted, EPA has promulgated regulations which directly affect issue~
raised by ARCO in the Seoping Document. In particular, on March 8, 1990, EPA
promulgated the new National Contingency Plan rNew NCP1. 55 Fed. Reg. 8666 .m~..
as well as regulations further interpreting the applicability of the RCRA Subtitle C
hazardous waste regulations to mineral processing wastes.
As you know, ARCO's analysis 01 RCRA as an ARAR in the Scoping Document was
based, in part. on EPA's April 11, 1989 Proposed Rule regarding mineral processing
wastes excluded by the Bevill Amendment. 54 Fed. Reg. 15316. In the cover letter to the
Scoping Document, ARGO indicated that it might submit a supplemental Scoping
Document analyzing the impacts, if any, of new mineral processing waste regulations on
the RCRA analysis provided in the Scoping Document This letter provides sueh an
analysis. We also informed And'llensink and Tom Eggert. at the Anaeenda Smelter
Annual Meeting that we would be providing an update to the Scoping Document.
This letter identifies issues and arguments raised by ARCO in the Seoping
Document that have been affected by regulations promulgated subsequent to the Scopin£
Document's submittal date. In particular. this letter addresses the impact 01 the New NCP,
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Letter to Charles Coleman, Duane Robertson, Thomas Eggert and Andrew Lensink
May 16, 1990
Page -2-
EPA's September 1, 1989 Final Rule retaining certain mineral processing wastes within
the Bevill Exclusion, 54 Fed. Reg. 36592.m~. ("the September 1, 1989 Final Rulej and
EPA's January 23, 1990 Final Rule retaining certain mineral processing wastes that were
conditionally retained by the September 1, 1989 Final Rule within the Bevill Exclusion. 55
Fed. Reg. 2322.mRQ. (the .January 23,1990 Final Rulej.
ARCO requests that the Agency consider the updated sections of the Scoping
Document presented in this letter in its analysis of RCRA ARARs for the Rue Dust
Operable Unit. Where a section of the Scoping Document has not been specifically
updated, ARCO requests that the Agency retain and utilize the original Scoping Document
in its ARARs analysis for the Rue Dust Operable Unit. The citations in parentheses below
are references to the Scoping Document
1. ARARs Must be Promulgated or Enacted and Effmve as of the Date of the
Record of D~cision (Vol. 1. Section II.H).
In Section II.H. of the Scoping Document, ARCO made the general comment
that in .order for a law or regulation to be an ARAR. it must be duly enacted or promul-
gated, and it must be effective, as of the date of the Record of Decision (.ROO"). EPA has
explicitly adopted this position in the New NCP:
Once a Record. of Decision is signed and a remedy chosen,
EPA will not reopen th3t decision unless the new or modified
requirel11ent calls into question the protectiveness of the
selected remedy. EPA believes that it is necessary to "freeze
ARARs. when the Record of Decision is signed rather than at
initiation of remedial action because continually changing
remedies to accommodate new or modified requirements
would. " . disrupt CERCLA cleanups. . . If ARARs were not
frozen at this point. promulgation of a new or modified
requirement could result In a reconsideration of the remedy
and a restart of the lengthy design process, even if protective-
ness is not compromised. This lack of certainty could
adversely affect the operation of the CERCLA program, would
be inconsistent with Congress' mandate to expeditiously
cleanup sites and could adversely affect PRP negotiations. . .
The policy of freezing ARARs will help avoid constant interrup-
tion, reevaluation, and redesign during implementation of
selected remedies.
Preamble.'to New NCP. 55 Fed. Reg. 8757.
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Letter to Charles Coleman, Duane Robertson, Thomas Eggert and Andrew Lensink
May 16, 1990 .
Page -3-
2. Bue Dust May Not Be Regulated as a liazardous Waste Until EPA Approves
.Montana Program Rev~ons (Vol. 1. Section III.C.2.a}.
In Section III.C.2.a of the Seeping Document, ARCO asserted that because
~ue dust and flue dust residues are currently exempt from regulation as a mineral
processing waste pursuant to i 3001 (b)(3)(A)~i), of RCRA. 8 regulations promulgated
pursuant to SubtitJe C of RCRA could not be applicable req~irements because a
necessary jurisdictional prerequisite for applicability, the presence of a listed or charac-
teristic hazardous was1e, was not satisfied at the Rue Dust Operable Unit. ARCO then
noted that, for processing wastes other than 39 wastes specifically retained within the
Bevill Exclusion by the April 17 Proposed Rule, 54 Fed. Reg. 15317, the Proposed Rule
provided that,
when this rule is promulgated in final form, mineral processing
wastes that have been temporarily excluded from regulation
under SubtitJe C of RCRA since 1980, except the 39 special
wastes. . .. may now be subject to Subtitle C requirements
beginning, at the latest, on or about February 23, 1990 Q.e.,
six months after publication of the Final Rule) (approximately
August 23, 1989) in those states t~o not nave aut~
tion to administer their own hazardous waste program in freu
of EPA. . . This proposal, if promulgated. will not be automati-
cally effective in authorized states, since the requirements will
not be imposed pursuant to the hazardous and solid waste
amendments of 1984 . -. In authorized states. the reinterpre-
.tmion and.J.he regulation of nonexcluded processing wastes
~be appl~e unti1 the state rev~its program to
,m.fopt eQuivalent requirements under. state law. (Emphasis
added.) 54 Fed. Reg. 15345.
The September 1, 1989 and January 23, 1990 Final Rules confirm ARCO's
position in the Seeping Document that flue dust is not subject to RCRA Subtitle C
regulation in Montana until Montana revises its hazardous waste program and EP A
approves the program revisions. The September 1, 1989 and January 23, 1990 Final
Rules state that they are 8not effective in authorized states, because [their] requirements
are not being imposed pursuant to the Hazardous and Solid Waste Amendments of
1984: 54 Fed. Reg. 36633; 55 Fed. Reg. 2347. In authorized states, such as Montana,
8tJle reinterpretation 01 the regulation of non excluded processing wastes will not be
applicable until the state revises its program to adopt equivalent requirements under state
law and receives authorization for these new requirements.. 55 Fed. Reg. 2347. States
are required to revise their programs to adopt equivalent standards to those set forth in
EPA's September 1, 1989 and January 23, 1990 Final Rule by July 1, 1991 if regulatory
changes only a~e necessary, or by July 1, 1992 if statutory changes are necessary. J.d.
These deadlines can be extended by up to six months. Thus, in authorized states such
-------
. letter to Charles Coleman. Duane Robertson. Thomas Eggert and Andrew lensink
May 16. 1990
Page -4-
as Montana. mineral processing wastes such as flue dust that were previously included
within the Bevill Exclusion but are no longer retained within the Bevill Exclusion by the
September 1. 1989 and January 23, 1990 Final Rules are not regulated as hazardous
wastes. ~ 53 Fed. Peg. 2343 rlf a previously Bevill excluded mineral processing waste
material is not yet a hazardous waste in the [authorized] state to which it is sent for
treatment, storage. or disposal. no Subtitle C requirements apply"} Such wastes will not
be regulated as hazardous wastes until Montana revises its program to address such
wastes and receives approval the program revisions from EPA. Soil and debris
containing such wastes also would not be subject to regulation under RCRA Subtitle C
since such soil and debris would not be derived from a hazardous waste. ARCO does
not anticipate that program revisions to address previous Bevill-excluded mineral
processing wastes and EP A approval of such program revisions will occur until after the
ROD date. The New NCP confirms that requirements must be promulgated and effective
as of the ROD date in order to be ARARs. ~ Preamble to New NCP, 55 Fed. Reg.
8757. Therefore, RCRA Subtitle C requirements should not be applicable requirements
for the Rue Dust Operable Unit.
- \
In Section III.C.2.b. of the Seeping Document, ARCO asserted that because
activities at the Ru"e Dust Operable Unit did not constitute treatment, storage or disposal.
a necessary jurisdictional prerequisite for RCRA regulations to be appficable requirements
was not satisfied. Therefore. RCRA Subtitle C regulations could not be applicable
requirements for the Aue Dust Operable Unit. In particular. the Scoping Document
discussed why activities contemplated for the Aue Dust Operable Unit did not constitute
8disposar as defined by RCRA. ARCO believes that the New NCP and other documents
which became available after the Seeping Document's submittal date provide additional
support for -ARCO's position that RCRA disposal regulations should not be applicable
requirements for the Aue Dust Operable Unit.
The Preamble to the New NCP contains a detailed explanation of activities
that do and do not count as .disposal: ~ Preamble to New NCP. 55 Fed. Reg. 8758-
8760. In the Supplemental Notice to the Proposed NCP. 54 Fed. Reg. 41566 (October
10, 1989) (the .October 10 Supplemental Notice8), EPA proposed two alternative
interpretations of .Iand disposal: Under the Agency's second alternative; hazardous
wastes could be excavated and redeposited either within the original unit or area of
contamination. or elsewhere at the site in a new or existing unit. without triggering
8disposal8 and thus RCRA Subtitle C requirements. ~ 54 Fed. Reg. 41566. 41569.
". On November 9. 1989. ARCO submitted extensive comments to the Agency
on the October 10. Supplemental Notice. which are attached and incorporated herein by
reference. In its comments. ARCO suggested the following definition of .Iand disposal.
for purposes of determining RCRA Subtitle C appficabirrty:
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letter to Charles Coleman. Duane Robertson. Thomas Eggert and Andrew Lensink
May 16.1990
Page -5-
The terms .unit. or .area of contamination. for purposes of
determining the applicability 01 LDRs to CERCLA of remedial
actions include: (1) the areal extent of contamination and all
suitable areas in close proximtty to the contamination neces-
sary for Implementation of the response action; (2) all areas
within the meaning of the term 'acilny- as defined in Section
101 (9) of CERCLA; and (3) noncontiguous facilities that are
reasonably related on the basis 01 geography. or on the basis
of the threat or potential threat to the public health, welfare or
the environment
This definition would be consistent with EPA's definition of .on-site. for pennitting
purposes. ~ New NCP 40 C.F.R. ~~ 300.5 and 3OO.4oo(e)(1); Preamble to New NCP,
55 Fed. Reg. 8688-90.' ARCO strongly believes that its proposed definition of disposal
in its November 9, 1989 comments is appropriate for determining when RCRA Subtitle C
requirements are applicable at CEACLA sites including the Rue Dust Operable Unit.
. In the Preamble to the New NCP, EPA specifically defers its final decision
addressing the interpretation 01 .Iand disposal. pending .review of the lengthy and
complex issues raised by comments on the Supplemental Notice. I Preamble to New
NCP, 55 Fed. Reg. 8760. As described in ~le New NCP. 'and disposal. only OCCurs
when RCRA hazardous waste is moved from one unit and placed in another. Preamble
to New NCP, 55 Fed. Reg. 8759. However, what constitutes a 'unit- lis not always self-
evident' As EPA notes in the Preamble to the New NCP,
EP A generally equates the CERCLA area of contamination with
a single RCRA land based unit. usually a landfaD. . .. The
reason for this Is thatthe RCRA regulatory definition of .landfill'
is generally defined to mean a land disposal unit which does
not meet the definition of any land disposal unit, and thus is
a general 'catch alii regulatory definition for land disposal
units. As a result,' a RCRA .Iandfill. could include a non-d"as-
crete land area on or in which there is generaDy disbursed
contamination. Thus. EP A beUeves JMULis aDprqpriattl
generally 10 consider C~l.A areas of contamiMiion a;~
single RCRA land based unit. or .~ (Emphasis added.)
Preamble to New NCP, 55 Fed. Reg. 8760.
, In addition, Section 104(d)(4) 01 CERCLA authorizes EPA to treat noncontiguouS facUlties as one facUlty
In circumstances where. -rwo or more noncontiguous facUitles are reasonably related on the basis a
geography. or on the basis of the threat, or potential threat 10 the public health or welfare or the
environrnent.8
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Letter to Charles Coleman, Duan'e Robertson, Thomas Eggert and Andrew Lensink
May 16,1990
Page -6.
/
'v
This discussion in the New NCP of what constitutes a .unit. further supports
ARCO's position In the Scoping Document that all of Smelter Hill clearly could be
considered as one .unit. See ARCO's discussion at Scoping Document, Vol. 1, p. 48-
53. As note~ in the Seeping Document, Smelter Hill is an area of contamination with
different concentration levels and types of hazardous substances, pollutants or con-
taminants. Therefore, placement of untreated flue dust or flue dust residues into a
repository on Smelter Hill should not constitute placement of such materials into a unit,
but rather a movement of materials within a unit. I .
In Section III.C.3.1. of the Scoping Document, ARCO states that it does not
expect that any of the criteria for the applicability of RCM land disposal restrictions
,LDRs.) will be met at the Aue Dust Operable Unit. Documents which become available
after the Scoping DoaJment's submittal date confirm ARCO's expectation that LDRs
should not be applicable requirements for the Aue Dust Operable Unit
, Under, EPA's .poncy for Superfund Compliance with the RCRA Land
Disposal Restrictions,. OSWER Directive 9347.1-02 (April 17. 1989) \the land Disposal
Restrictions Policy,' RCRA LDRs are only applicable to CERCLA cleanups when three
criteria are met: '(1) the CERCLA action constitutes placement p.e.. land disposal); (2)
the CERCLA waste is a RCRA hazardous waste; and (3) the RCM waste is restricted
from land disposal at the time of placement. Land Dispos~ Restrictions Poficy, p.4.
In the October 10 Supplemental Notice, EPA discusses the types of activities
that would constitute land disposal under the first criteria for LDR appncability. 54 Fed.
Reg. 41566. As noted above. ARCO submitted comments to the Agency regarding the
October 10, 1989 Supplemental Notice which are attached and Incorporated herein by
reference. While the New NCP has deferred any final decision on what types of activities
constitute land disposal (preamble to the New NCP, 55 Fed. Reg. 8762), under EPA's
existing statements of what constitutes a .unit. for the purposes of land disposal, place-
ment 01 flue dust In a repository at the Smelter Hill Site would not constitute .Iand
disposal. as defined in the Proposed NCP, the October 10 Supplemental Notice, the land
Disposal Restrictions Policy, or ARCQ's comments on the October 10 Supplemental
Notice. Therefore, the first criterion 01 applicability of LDRs, i.e., CERCLA action
constituting placement. is not satisfied by the Flue Dust Operable Unit
I RCRA Subtitle C requirements would not be applicable In any case to the areas at the Aue Dust
Operable Unit from which materials are removed. A!;, stated In the Preamble 10 the Proposed NCP.
. If some of the waste al a she Is moved Into another unit, but other waste Is left behind In
the original unit. -wxI disposar applIes only with regard to the waste that Is moved Into
another unit. 53 Fed. Reg. 51444.
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Letter to Charles Coleman, Duane Robertson, Thomas Eggert and Andrew Lensink
May 16, 1990
Page -7-
With respect to EPA's second criterion for the applicability of LDRs, i.e., the
CERCLA waste is a RCRA hazardous waste, flue dust is still not subject to regulation as
a hazardous waste in Montana. As noted above, until Montana revises its authorized
program to adopt the September 1, 1989 and January 23, 1990 Final Rules and EP A
approves these revisions, flue dust is not subject to hazardous waste regulation in
Montana. Therefore, the second criterion for RCRA LOR applicability, the presence of a
hazardous waste, is not met. . .
Finally, the third criterion for RCRA LOR applicability, I.e., the RCM waste.
is restricted from land disposal at the time of placement, is not satisfied by the Rue Dust
Operable Unit. Wastes that are no longer retained within the Bevill Exclusion are
considered by EPA to be .newly identified- wastes for purposes of estabfishing LORs
under ~ 3004{g) of RCRA. 54 Fed. Reg. 36624; 54 Fed. Reg. 48372, 48492; 55 Fed. Reg.
2346-2347. EPA has proposed that newly identified mineral processing wastes not be
subject to the BDAT standards that the Agency proposed on November 22, 1989 for
characteristic hazardous wastes. 54 Fed. "Reg. 48492-48493; 55 Fed. Reg. 2348-2347.
Instead, such wastes would. be subject to further study before BOAT Is established for
such wastes. 54 Fed. Reg. 48493. EP A has expressly acknowledged that it 8has not yet
performed the technical analyses necessary to determine if the treatment standards
proposed today as BDAT for EP toxic hazardous w~stes can be achieved in treating the
various mineral processing wastes.. 54 Fed. Reg. 48493. ARCO is not aware of any
technical analyses that the Agency has performed that would fully demonstrate that the
BDAT standards proposed for characteristic wastes in the Agency's November 22, 1989
Proposed "Third-Third. rulemaking are appropriate for mineral processing wastes.
-
With respect to son and debris, EPA determined in the Preamble to the New
NCP that,
. . . until specific standards for sons and debris are developed,
current BOAT standards are generally inappropriate or
unachievable for son and debris from CERCLA response
. actions.
Preamble to New NCP, 55 Fed. Reg. 8761.
Even if EPA ultimately establishes BOAT standards for mineral processing
wastes such as flue dust, such standards would not be applicable in authorized states
like Montana until the authorized state revises its program to include flue dust and EP A
approves the revised program. ~ 54 Fed. Reg. 48493 ("Thus, in these [authorized]
states, these mineral processing wastes would only be hazardous wastes if they are
included within the scope of the states' authorized program. If they are not, they would
not be hazardous wastes until an amended state's program including them is authorized.
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Letter to Charles Coleman, Duane Robertson, Thomas Eggert and Andrew Lensink
May 16, 1990
Page -8-
,
. i
.Q.oV.fter authorization woul.Q the land disposal prohibnions apply in that state:)
(emphasis added).
5.
Montana Hazardous Waste Mana<.;Jement Act.
In Section II.C.4. of Volume 2 of the Scoping Document, ARCO analyzed
Federal RCRA Subtitle C requirements because Montana's requirements are essentially
equivalent to the Federal requirements and may not be more stringent. The Preamble
to the New NCP provides that, 8EPA notes that, in general, state regulations under
federally authorized programs are considered federal requirements.. 54 Fed. Reg. 8762.
Therefore, ARCO reiterates that EPA should limit its consideration of potential RCRA
ARARs for the Rue Dust Operable Unit to Federal RCRA Subtitle C requirements.
Please include this letter in the administrative record for the Rue Dust Operable
Unit. As we discussed during the March 21, 1990 Anaconda Smelter meeting, we would
be glad to meet with you at your convenience to discuss ARARs for the Rue Dust
Operable Unit. If you have any questions, please don't hesitate to call me or Bob
Lawrence at (303) 293-6508. Thank you for your consideration of this update letter.
Sinltt? ~
Pamela S. Sbar
PSS:1v
cc:
Sandra M. Stash
,>
-------
F. N. Ramseier Consultin9, Inc.
7030 South Windsor Street
Littleton, CO 80123
Telephone: (303) 979-0735
FAX: (303) 979-0735
July 16, 1991
I
, ~
Ms. Robin Bullock
Superfund coordinator
Atlantic Richfield Company
P.O. Box 1491
Anaconda, MT 59711
By FAX
Dear Robin:
As you requested in your letter to Terry and me, dated June
28, 1991, I have talked to at least fourteen people that"
have worked on superfund sites that have used, or intend to
use, solidification/fixation as remedial technologies for
their wastes. Most discussions were with members of the EPA
staff, often those associated with project management or
technology research.
Based on my review, I believe that ARCO has thoroughly
studied the solidification/fixation of Anaconda flue dust,
and has recommended a safe treatment method. The following
comments have been selected from "the notes that I have taken
during my discussions.
Artech's attempt to discredit the ANS 16.1 test as an
indicator of long-term stability may not be an important
issue. As we have 6aid before, EPA does not have a standard
method for determining long-term stability of treatment
residues." Paul DePercin, at the EP~ Center for
Environmental Research in Cincinnati, confirms that the TCLP
is the only criteria used by his office to determine the
success, or failure, of a treatment technology.
Garth Conner, EPA Project Manager at the Craig Farm Drum.
site in Pennsylvania, states that lonq-term stability is not
an issue because the treatment residues at this site will be
placed 1n an engineered repository, as will the residues at
Anaconda.
Tony DeAngelo, when discussing the Smith's Farm site in
Kentucky, again states that TCLP is the passing criteria,
and that residues will be placed in a repository with a
leachate collection system and a 60il cap.
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2
At the pepper's steel and Alloys eite in Florida, Dian.
scott, the tPA project Manager, 8a1d that successful
so11d1flcation/f1xation was completed in 1989 on Pb and As
contaminated 80il, usln9 a mixture of Portland Cement and
fly ash. The soil was excavated, mixed with additives, and
returned to the excavation, without an impermeable barrier,
and covered with crushed limerock.
In Florida, the remediation of the Sapp Battery site 1s in
the treatability stage. EPA's Martha Berry states that the
passing criteria ia, &9ain,. TCLP but that the .tate uses ANS
16.1 as an indicator of long-term stability. When using the
ANS 16.1 test only the leachate 18 analyzed, because the
fixed material ultimately will be a monolith. The
solidified .residue ~ill be returned to the excavated site,
not an engineered repository.
Chromium at the Industrial Waste Control site in Arkansas
was stabilized using cement and fly ash. This project,
completed i~ Harch, 1991, used a slightly different
treatment method. The soil was mixed with fly ash and
allowed to set for "14 days. Then the material was moved to
the repository and mixed with cement just prior to
placement. No long-term tests were required.
In aummary:
1. The EPA does not hav8 a standard test for determinin9 the
long-term stability of fixed residues;. .
2. 'I'~T.P 1R r.nmmnn1Y URAd .as the DassinC1 criteria for
determination uf hK~~~duu~ UbQLQ~L~£~~L~~aj
J. At:. 1:ne one 81t8 wnere luns J.O. J. WiUS U::iYU XUL \,tltH.£U~ ",,,tI
long-term stability, only the leachate was analy~ed;
4. Long-term stability is not an issue if the fixed residue
is placed 1n an engineered repository with a leachate
detection system;
5. It is not uncommon for solidified residues that'pass the
TCLP to be returned to the original excavation without an
extensive engineering system.
In my opinion, ARCO has thoroughly studied the
solidification/fixation alternative and should be able to
effectively.counter any opposition from other alternatives.
Best regards,
pc: Terry McNulty
P. N. Ramse!er
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ATTACHMENT 2
EPA RESPONSES TO ARCO COMMENTS TO THE
RISK ASSESSHENT
-------
ENFORCEXE~7 COSFIDE~TIAL: CATEGORY 1,
PRIVILEGED ATTORNEY WORK PRODUCT
vie S!l~1CJIfs, J/1
Submitt.ed to:
Fluor Daniel. Inc.
18333 Preston Road
Suite 200
Dallas, TX 75252
Attention:
Mark deLorimier (1 copy)
Bill Hall (1 copy)
TR-1165-30
EPA RESPONSES TO THE ARCO COAL COMPANY ENDANGERMENT ASSESSMENT
REVIEW COMMENTS FOR THE FLUE DUST OPERABLE UNIT
Risk Assessment Support For
The Anaconda Smelter Site
Prepared Under
Program No. 1541
for
Subcontract No. 619800-9-K003
Under
Contract No. 68-W9-0013
for
ICAIR Work Assignment No. 041541
EPA Work Assignment No. 02-8P18
Contact:
Mr. Gregory E. Schiefer
Telephone:
(216) 464-3291
November 1, 1990
-------
iJle S!lSle/lfs' Jif{
1.0
2.0
3.0
.
INTRODUCTION
. . . .
TABLE OF ~ONTENTS
. . . . .
........
. . . . . . . . .
SUMMARY. . .
ARCO COMMENTS AND EPA RESPONSES
. . . . . . . . .
. . . .
EPA
GSD
IU/BK
RAGS
. . . .
. . . .
............
. . . . . . .
LIST OF ACRONYMS
. Environmental Protection Agency
Geometric Standard Deviation
Integrated Uptake/Biokinetic
Risk Assessment Guidance for Superfund
i
PAGE
1-1
2-1
,.
v'
3-1
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nle SflSfeJlfs, J;
1.0
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) is currently pursuing
evaluation and cleanup activities at the Anaconda Smelter site near Anaconda,
Montana. Included among the concerns of this site are a number of piles of
flue dust from past smelter operations. The risk posed by these piles has been
evaluated in a Baseline Risk Assessment. This Risk Assessment has been
reviewed by the ARCO Coal Company, and ARCO has supplied EPA with a document
detailing their comments and recommendations. This current report summarizes
ARCO's recommendations, and provides responses to those recommendations as
part of EPA's responsiveness su~ary.
,',
1-1
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nit S/lSICllfS, J/J
2.0
3.
ARCO COMMENTS AND EPA RESPONSES
1.
ARCO stated that the use of models to estiDate air exposures on-site
were at least two orders of magnitude too, high, based on comparison
with recent monitoring data from an on-site station. ARCO
recommended using the new monitoring data rather than the values
calculated from the model.
Response:
EPA does not believe this is appropriate. since. under current
conditions. flue dust piles on site have been treated with
surfactant that significantly reduces air emissions. However. under
the no-action (baseline) alternative. it Dust be assumed that
spraying with surfactant is discontinued. and that the effects of
the current surfactant disappears within several years. This would
revert the site to conditions where air emissions would be much
higher. as was the case in the past.
2.
ARCO criticized the use of monitoring data to estimate risks from
flue dust at off-site locations (East Anaconda), stating that this
method overestimates the risk from flue dust since other sources
also contribute to current air levels.
Response:
EPA agrees that all contaminants in air should not be attributed to
flue dust. The assess~ent makes this point several times. and
emphasizes that risks estimated from monitoring data represent an
upper limit of the current risks from flue dust. On the other hand.
the use of surfactant results in a decrease in air emissions
compared to the baseline (no-action) alternative. so current
monitoring data may underestimate this situation.
ARCO stated that measured values of contaminants in groundwater
beneath the site should not be entirely attributed to flue dust.
ARca further stated that evaluation of groundwater w~s beyond the
scope of this risk assessment. since it will be addressed in the
RIfFS for Smelter Hill.
Response:
EPA agrees that all contaminants in groundwater should not be
presumed to originate from flue dust. although EPA believes that.
flue dust is an important source of groundwater contamination. The
Risk Assessment emphasizes several times that the total risk from
groundwater should not be attributed to flue dust alone. but that it
represents an upper bound for that risk. EPA does not agree that
evaluation of groundwater is beyond the scope of this Risk
Assessment, since flue dust does contribute to groundwater
contamination at the site.
2-1
-------
bfe SUSIC/lfs' ~
4.
ARca criticized the calculation of doses in the risk assessment,
stating that the values e~?loyed were not in accord with th~ RAGS
concept of a reasonable m~ximum exposure. ARCa provided ~eclfic
recommendations for revised dose calculation parameters.
Response:
The Flue Dust risk assess~ent was prepared according to the guidance
in the Superfund Public Health Evaluation Manual (SPHEM), prior to
release of the RAGS. Nevertheless, the document has been revised to
bring the methods used to calculate doses into accord with the RAGS
guidance. The revised document provides specific justification or
rationale for all parameters used in calculating dose.
s.
ARca specifically criticized the duration and frequency assumptions
used to evaluate the exposure of dirt bike riders at the flue dust
piles, stating ~hat the values used were implausible.
Response:
The exposure duration and frequency terms were based on national
average statistics for outdoor activities similar to dirt bike
riding. EPA acknowledges that use of these values is uncertain and
that the values might be overly conservative. In order to obtain
more applicable data, EPA performed an informal survey on the actual
frequency and duration of dirt bike riding or mountain bike riding
at the Anaconda Smelter site. These data were used to develop a
more accurate estimate of bike rider exposure. As ARCa had
suggested, the survey data did indicate that bike riders were likely
to visit the flue dust piles on Smelter Hill less frequently than
previously assumed, so ~his term has been adjusted downward. Also,
EPA agrees that not all the time spent on Smelter Hill will involve
contact with flue dust, so an adjustment has been made for this.
However, the survey also revealed that bike riders are likely to be
exposed not for just six years (as was previously assumed), but for
an indefinite period, so the exposure duration term has been
increased accordingly.
6.
ARCO criticized the' use of the RfD approach for evaluating health
risks from lead, and reco~ended using the IU/BK model instead.
Response:
EPA agrees, and has revised the document accordingly, using the
LEAD4 computerized version of the IU/BK model.
2-2
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bfe S!lSle/lfs' life
10.
7.
ARCO stated that the Risk Asse~sment did not discuss the nonlethal
nature of arsenic-induced skin cancer. and that there was inadequate
discussion of factors such as a nonlinear dose-response curve and
reduced bioavailability that tend to overestimate the risk of cancer
from arsenic.
Response:
The nonlethal nature of skin cancer was already noted (see page 4-2
of the Endangerment Assessment dated 12/20/89). EPA has expanded
the discussion of nonlethality and nonlinearity somewhat. The
discussions of possible beneficial effects and bioavailability are
judged to be adequate without expansion.
8.
ARCO noted a typographical error in the critical renal
concentration value for cadmium.
Response:
The error has been corrected.
9.
ARCO stated that the Risk Assessment failed to adequately identify
and discuss the impact of many uncertainties in the final risk
estimate. including:
o
o
o
o
o
Use of an unverified RfD for lead
Use of inappropriate soil intake rates
Use of monitoring data
Use of modeled air values inconsistent with.monitoring data
Overestimation of exposure duration and frequency
Response:
All of these uncertainties are discussed in Section 8.
ARCO recommended (see Appendix B) that the 95th percentile for dose
estimates be calculated using the geometric standard deviatioy ~gSD)
for the entire data set and the equation X 5 h - X "GSD "
rather than by using the approach specifiea in themRRcg~
Response:
EPA does not believe there is sufficient information on the shape of
various dose distribution curves to know whether this equation is
generally appropriate. Also. there are usually insufficient data on
the value of the GSD for each of the input parameters to permit
calculations of a GSD for the product.
2-3
-------
flle S!lSleJlfs, lit
11.
.cJ
ARCO criticized the soil ingestion rates of 200 and 100 mg/day for
children and adults, respectively, as specified in the OSWER
directive. ARCO stated that the most recent study (Calabrese et ale
1989) indicated the arithmetic mean and median soil ingestion rates
for children were 87 and 39 mg/day, and that this was supported by
the "best-fit" with the IU/BK model. The best value for adults was
10 mg/day, based on inferences drawn from studies on urinary arsenic
levels at Mill Creek.
Response:
EPA believes that soil ingestion by children and adults is a complex
function of numerous site-specific parameters (percent ground cover,.
rainfall, windspeed. number of snow-covered days, etc.) and human
activity patterns (time spent playing or working outdoors.
frequency of hand washing. etc.). Consequently, intake values are
likely to vary widely between individuals and between sites. EPA
believes that the current data. including the study by Calabrese et
a1. 1989. strongly support the conclusion that the values specified
in the OSWER directive are within the likely range of upper 95th
percentile intake values. The calculations recommended by ARCa to
define mean or median values are not appropriate for use in
calculation of reasonable maximum doses. Also. EPA does not agree
that the mean value proposed by ARCO is appropriate for use at Clark
Fork sites since it was based on measurements in Massachusetts. EPA
believes that the best data set to employ in deriving an average
intake.1eve1 is the report of Binder et a1. (1986), since this study
was performed in East Helena.
12.
ARC a stated that arsenic in soil is less bioavailab1e than arsenic.
ingested in other media.
Response:
EPA agrees
to account
avai,lab1e.
reasonable
of arsenic
that this might be true and will adjust dose calculations
for this when reliable site-specific data become
In the absence of such data. EPA believes it is
and prudent to assume that the relative bioavailability
in soil (compared to that in other media) is 1.0.
13.
ARCO stated that the "threshold" (Le.. cleanup goal) concentration
for arsenic in soil should be calculated from the equation
C .. DT/(IR x AF)
where
C =
DT =
IR ..
AF ..
arsenic concentration (ug/g soil)
detoxification threshold (ug As/day)
Soil ingestion rate (gm/day)
Absorbed fraction
Based on values of 75 ug/day for DT. 0.2 g/day for IR and 0.25 for
AF. ARCO calculated a reasonable maximum "threshold" value of
3.330 Ug/g for children exposed to arsenic.
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Response:
EPA has not concluded that there is a nonzero threshold for cancer
risk from arsenic, so this entire approach is not considered
appropriate. Even if the equation were to be used. EPA does not
agree with ARGO's input parameters: (1) the "threshold" (if there
is one) has not been defined. and could easily be above 1.000 ug/day
for adults; and (2) the absorption fraction is not a relevant term
and should not be included in the equation unless the "threshold" is
expressed as an absorbed dose (it is not).
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3.0
SUMMARY
EPA thanks ARCO for its comments and suggestions regarding the evaluation of
exposure and risk due to flue dust at the Anaconda Smelter. EPA agrees with
some of ARCO's suggestions, and has revised the risk assessment accordingly.
However, .EPA does not agree with other of ARCO's suggestions for the reasons
given in this report. Also, EPA has chosen to be somewhat more conservative
than ARCO suggested with respect to several assumptions and values. EPA
acknowledges that some of these decisions may lead to an overestimate. of
exposure and risk but, in view of the uncertainties associated with the risk
assessment process, believes this is necessary and prudent in order to ensure
protection of human health and the environment.
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E~FORCE~~~T CO~FIDE~TIAL: CATEGORY 1,
PRIVILEDGED ATTORNEY ~ORK PRODVCT
iJle SusIe/lIS, };
Submitted to:
Fluor Daniel. Inc.
18333 Preston Road
Suite 200
Dallas. TX 75252
Attention:
Mark deLorimier (1 copy)
Mike Glaze (1 copy)
TR-1165-27
EPA RESPONSES TO THE ARCO COAL COMPA1~ ENDANGERMENT ASSESSMENT
SCOPING DOCUMENT FOR THE FLUE DUST OPERABLE UNIT
Risk Assessment Support For
The Anaconda Smelter Site
Prepared Under
Program No. 1541
for
Subcontract No. 619800-9-K003
Under
Contract No. 68-W9-0013
for
ICAIR Work Assignment No. 041541
EPA Work Assignment No. 02-8P18
Contact:
Hr. Gregory E. Schiefer
Telephone:
(216) 464-3291
'March 12, 1990
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1.0
2.0
3.0
I
"'-
INTRODUCTION
TABLE OF CONTENTS
...............
. . . .
.......
ARCO RECO~~ATIONS ~~ EPA RESPONSES
. . . . . . .
SU1i!iARY . . . . . . . . . . . . . . . . . . .
EPA
IU/BK
RfD
RI/FS
. . . .
......
LIST OF ACRONYMS
Environmental Protection Agency
Integrated Uptake/Biokinetic
Reference Dose
Remedial Investigation/Feasibility
i
Study
PAGE
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.Die S!ls/eIJIs, J;
1.0
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) is currently pursuing
evaluation and cleanup activities at the Anaconda Smelter site near Anaconda,
Montana. Included among the concerns of this site are a number of piles of
flue dust from past smelter operations. The risk posed by these piles has been
evaluated in an Endangerment Assessment. During the time that this
Endangerment Assessment was being proposed, the ARCO Coal Company submitted to
EPA a Scoping Document that presented ARCO's views and recommendations
regarding a number of issues relevant to the performance of the Endangerment
Assessment. This current docucent summarizes ARCO's recommendations, and
provides responses to those recommendations as part of EPA's responsiveness
summary.
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ARCO RECOMMENDATIONS A~~ EPA RESPONSES
1.
ARCO recommended that the risk assessment focus on the incremental
risks due specifically to flue dust. and not to combine this risk
with risks from other sources.
Response:
EPA agrees, and has sought to do this where the data permit.
2.
ARCO recommended that the risks associated with exposure to flue
dust be compared to risks from background exposures in Montana.
Response:
EPA agrees that a comparison of site-specific risks to background
risks (from the same chemicals) is useful in establishing
perspective, and has provided this information where the data
permit.
3.
ARCO recommended that risks should be evaluated both for current
conditions (including twice-yearly spraying of the flue dust and
institution controls to limit access) and a base-line (no-action)
case.
Response:
The Remedial Investigation/Feasibility Study (RI/FS) process
requires preparation of a base-line (no-action) evaluation, and that
is the purpose of the Endangerment Assessment. This evaluation
assumes that access is not restricted and that remedial activities
(such as spraying) are discontinued. If significant risk is
associated with the no-action alternative, then the efficacy of
current institutional controls may be evaluated along with other -
remedial alternative&-- However, institutional controls do not meet
the criterion of being a permanent solution.
4.
ARCO recommended considering three potentially exposed populations:
. Theoretical future on-site residents
. Incidental on-site visitors
. Current off-site residents
Response:
EPA agrees and has sought to evaluate exposure and risk for these
groups.
5.
ARCO stated that existing monitoring data were adequate to show that
quantitative assessment of off-site risk is not necessary.
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Response:
EPA agrees that existing monitoring data support the view that flue
dust concentrations in air decrease as a function of distance from
the source (as would be expected), but does not agree that it is
unnecessary to evaluate off-site risk. Such an evaluation is
important in fully characterizing the risk associated with the
no-action alternative and is needed to characterize the efficacy of
various remedial alternatives.
6.
ARCO stated that air is expected to be the primary migration route,
but that quantification of air migration is likely to be difficult
due to the complex meteorology of the site. Direct measurements of
contaminant levels in air cannot be used since they do not
distinguish flue dust from other sources. If modelling is
attempted, it must be validated against site monitoring data, using
this as an absolute upper limit.
Response:
EPA agrees that air erosion and dispersion is the main route of
contaminant migration. EPA also agrees that direct monitoring data
are not specific for flue. dust, and that mathematical modelling of .
flue dust dispersion is required to separate the risk of flue dust
from other sources. EPA also agrees that application of models to
this site is difficult. In fact, EPA's attempt to model air
dispersion of flue dust did not appear to give reasonable resplts
off-site. Consequently, those calculated values were not used to
estimate flue dust-specific risk to off-site populations. Rather,
as ARCO suggested, monitored values were used as an estimate of the
upper limit of flue dust exposure.
7.
ARCO states that migration of flue dust in groundwater and surface
water is not expected to be as significant as air migration, and
that consideration ai-groundwater is beyond the scope of the Flue
Dust Operable Unit.
Response:
Whether surface water and/or groundwater transport are as
significant as a1r 1s irrelevant; both pathways must be considered
in assessing the risks posed by the flue dust piles. However, EPA
believes current data are not adequate to quantify the specific
impact of flue dust on either surface water or groundwater, and so
bas evaluated these patbways qualitatively. Also, EPA has chosen to
include risk from groundwater directly beneath the site in the
evaluation of risks to hypothetical future residents. It is
made clear in the Endangerment Assessment that not all the risk due
to groundwater may be due to flue dust, but that the fraction of the
risk in groundwater tbat is specifically due to flue dust is not
'. known.
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8.
ARCO provided an algorithm for calculating the concentration of
contaminants in indoor air as a function of the concentration of
contaminants in outdoor air and in indoor house dust. ARCO
recommended this algorithm for evaluating indoor inhalation
exposures to flue dust.
Response:
EPA agrees that it is important to consider inhalation exposure to
flue dust in indoor air. However. for the purposes of the present
evaluation. EPA believes this model i8 not sufficiently
well-established to warrant inclusion. Rather. EPA prefers to make
the conservative assumption that the concentration of contaminants
in indoor air is equal to that in outdoor air. EPA acknowledges
that this may lead to an overestimate of exposure. and has
identified this as a source of uncertainty in its analysis.
9.
ARCO provided algorithms for calculating the concentration to
specific contaminants in house dust. based on the concentration in
outdoor soil. ARCO recommended that these algorithms be used in
evaluating exposures due to inhalation or ingestion of house dust.
Response:
EPA agrees that it is important to consider exposure to contaminated
house dust. However. EPA considers that the algorithms proposed by
ARCO are not sufficiently well-established or validated to be
employed in the Endangerment Assessment. Rather. EPA prefers to
make the conservative (and simplifying) assumption that the
concentration of contaminants in house dust is equal to that in
outdoor soil. EPA acknowledges that this may lead to an
overestimate of exposure. and has identified this as a source of
uncertainty.
10.
ARca stated that th~xposure pathways of concern were inhalation
and ingestion of flue dust. and that dermal exposure was not of
concern. since metals are poorly absorbed through the skin.
Response:
EPA agrees that inhalation and ingestion of flue dust are important.
and that dermal uptake of metals is sufficiently small to be
neglected.
11.
ARca recommended that average lifetime exposures be calculated on
the assumption that a person is exposed at the site for nine years
(best case) or 30 years (worst-case) out of a lifetime of 75 years.
Response:
> EPA agrees that many people will not reside near the site for their
entire lifetimes. However. estimating cancer risks from
less-than-lifetime exposure 15 problematic. since the magnitude of
the risk from such an exposure depends on the mechanism of action of
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1.'i/'" ~YStClJ1S. JJ;
the carcinogen. EPA prefers in this case to evaluate cancer risks
based on the assumption that an individual is ~xposed their entire
lifetime. This may result in an overestimate of risk to individuals
who do not reside their whole life time near the site, and this has
been identified as a source of uncertainty. In keeping with EPA
guidance (Risk Assessment Guidance for Superfund, December 1989), a
value of 70 years for a lifetioe was used.
12.
ARCO stated that exposure to flue dust in air should be assu~ed to
occur only 247 days/year, to account for climatic factors.
Response:
EPA agrees that erosion of flue dust depends on climatic factors,
and that erosion is likely to be minimal when the piles are frozen
or snow-covered. EPA believes the most appropriate value to use for
non-snow days is 215 days/year. This value will result in a
somewhat lower estimate of exposure than the value recommended by
ARCO.
13.
ARCO recommended using the value of 3.07 hours/week spent outdoors
(as described in the Exposure Factors Handbook) for evaluating
inhalation of flue dust in air.
Response:
Since EPA has chosen to assume the concentration of flue dust is
equal in outdoor air and indoor air (see discussion under 2.8), the
distribution of time spent indoors and outdoors becomes irrelevant.
If exposure indoors and outd~ors were to be evaluated separately, it
would be necessary to calculate aveage time outdoors based on
site-specific assumptions, as described in the Exposure Factors
Handbook. The value of 3~07 hours/week cited in the Exposure
Factors Handbook is not intended to be a recommended value. Rather,
it is the result of a sample calculation based on a hypothetical set
of activity assumptiQns.
14.
ARCO recommended that incidental visitors to the site be assumed to
be teenagers and adults, and that a reasonable worst-case exposure
assumption is two hours/month.
Response:
EPA agrees that it is reasonable to assume that site visitors are
most likely to be teenagers or adults. EPA has chosen dirt bike
riders to represent the maximally exposed site visitor. Based on
data in the Exposure Factors Handbook for time spent in a similar
activity, EPA has used 2.62 hours/week as a best case and 15.3
hours/week as an upper limit.
15.
ARCO stated that the soil ingestion rates for children (200-800
,mg/day) provided in the Exposure Factors Handbook are too high, and
that recent studies not considered in developing these estimates
indicate that a lower value is approximate. For adults, ARCO
recommended a value. of 10 mg/day.
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lJfe S!ls/ellfs' ,
Response:
EPA believes available data are not sufficient to establish
clear-cut estimates of average soil intake by children or adults.
For this reason. EPA has adopted as an inter~o policy the use of 200
mg/day (best estimat~) or 800 mg/day (upper-bound) for 50il intake
by a child. EPA will use this estimate until a scientific consensus
can be developed on this issue. For adults. no policy has been
established. Data summarized in the Exposure Factors Ha~dbook
indicate values of 10-100 mg/day might be appropriate for average
intake by an adult. In order to be conservative. a value of
100 mg/day has been assumed.
16.
ARCO recommended that ingestion of solI for less than lifetime
exposure should not be assumed to occur at a time in life when
intake rates are highest. Instead. average lifetime intake rates
should be used. which is equivalent to assuming that exposure is
equally likely to begin at any age.
Response:
EPA does not agree that this is appropriate. When a less than
lifetime exposure is considered. it is important to focus on the
most sensitive subpopulat~on~ In the case of solI ingestion. this
i8 clearly young children, who ingest more soil than adults.
Calculations of the average lifetime dose ignores this and would
seriously underestimate risk to children.
17.
ARCO noted that there is uncertainty regarding the cancer potency
factor for,arsenic. and that this must be addressed as a qualifying
factor in the Endangerment Assesgment.
Response:
EPA agrees. and has PAovided a discussion of the issues currently
under debate regarding the carcinogenicity of arsenic.
18.
ARCO recommended that the Reference Dose (RiD) for cadmium in food
be used rather than the RfD for cadmium in water. asserting that it
i8 likely tbe bioavailability of cadmium in soils will be even less
than for cadmium in food. '
Response:
EPA does not believe there are adequate data to establish that,
metals in flue dust are not readily bioavailable. EPA has included
a bioavailability term in the calculation of dose for both
inhalation and ingestion exposures, but the value of this term has
been assumed to be 1.0. This may be revised'if specific data on the
bioavailability of flue dust become available.
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1..'if( S!lS/l11Is' Jill
19.
ARCO recommended using the integrated uptake/biokinetic (IU/BK)
model developed by Harley and Kneip for evaluating the health risks
of lead at this site. This would include use of gastrointestinal
absorption factors to account for differential absorption of
different lead compounds. Specifically, ARCO recommended a'
bioavailability factor of 0.25 for lead at mining sites.
Response:
EPA agrees that the IU/BK model is useful in evaluating the health
risks of lead, and has used a simplified version as one means of
evaluating health risk from lead at this site. However, as noted
above, EPA does not believe available data establish that lead in
flue dust has low bioavailability, and has employed a value of 1.0
rather than 0.23'1 for this parameter.
. ~)
,--.
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flle $uS/tills' JJ1(.
3.0
SUMMARY
EPA thanks ARCOfor its comments and suggestions regarding the evaluation of
exposure and risk due to flue dust at the Anaconda Smelter. EPA agrees with
many of ARCO's suggestions. and has acted accordingly. Ho~ever. EPA has
chosen to be somewhat more conservative than ARCO suggested ~ith respect to
several assumptions and values. EPA acknowledges that some of these decisions
may lead to an overestimate of exposure and risk but. in vie~ of the
uncertainties associated ~ith the risk assessment process. believes this is
necessary and prudent in order to ensure protection of human health and the
environment.
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