910R96020
PB95-964604
EPA/ROD/R10-95/122
April 1996
EPA Superfund
Record of Decision:
Commencement Bay Nearshore/
Tideflats (O.U. 2), Tacoma, WA
3/24/1995
-------
RECORD OF DECISION
COMMENCEMENT BAY NEARSHORE/
TIDEFLATS SUPERFUND SITE
OPERABLE UNIT 02
ASARCO TACOMA SMELTER FACILITY
RUSTON AND TACOMA, WASHINGTON
March 1995
U.S. Environmental Protection Agency
Region 10
-------
TABLE OF CONTENTS
1.0 SITE DESCRIPTION . 1-1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2-1
2.1 HISTORICAL SITE ACTIVITIES 2-1
2.2 ENFORCEMENT ACTIVITIES 2-1
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 3-1
4.0 SCOPE AND ROLE OF OPERABLE UNITS 4-1
4.1 SCOPE OF CURRENT WORK 4-1
4.1.1 OU O2 - Asarco Tacoma Smelter 4-1
4.2 OTHER RELATED ACTIVITIES 4-2
4.2.1 OU O4 - Asarco Off-Property (Ruston/North Tacoma Study
Area) 4-2
4.2.2 OU O6 - Asarco Sediments 4-2
4.2.3 OU O7 - Demolition and Surface Water Controls 4-2
5.0 SUMMARY OF SITE CHARACTERISTICS 5-1
6.0 DESCRIPTION OF SITE RISKS 6-1
6.1 IDENTIFICATION OF CONTAMINANTS OF CONCERN (SCREENING
ANALYSIS) : 6-2
6.2 EXPOSURE ASSESSMENT 6-2
6.2.1 Identification of Site Uses, Exposed Populations and Exposure
Pathways 6-2
6.2.2 Calculation of Exposure 6-4
6.3 TOXICITY ASSESSMENT 6-5
6.4 RISK CHARACTERIZATION 6-7
6.5 UNCERTAINTY ANALYSIS 6-8
6.5.1 Comparison of the Risk Assessment Results to Superfund
Regulations and Guidance 6-9
6.6 ECOLOGICAL RISK ASSESSMENT 6-10
6.7 EPA'S CLEANUP OBJECTIVES AND TWO-PHASE APPROACH 6-10
7.0 DESCRIPTION OF ALTERNATIVES 7-1
7.1 SUMMARY OF ALTERNATIVES 7-1
7.2 SIGNIFICANT PUBLIC COMMENTS AND ADDITIONAL ANALYSES ... 7-7
7.2.1 On-Site Containment Facility Comments 7-7
7.2.2 Soil Treatment Comments 7-9
7.2.3 Shoreline Armoring Comments 7-10
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES 8-1
9.0 THE SELECTED REMEDY 9-1
9.1 PLANT SITE SOILS 9-1
9.1.1 Excavate Soil and Granular Slag From Five Source Areas 9-1
9.1.2. On-Site Disposal 9-2
-------
9.1.3 Capping the Site (PSS and slag and the slag peninsula) 9-2
9.2 DEMOUSH REMAINING BUILDINGS AND STRUCTURES 9-3
9.3 SURFACE WATER 9-4
9.4 SHOREUNE ARMORING 9-4
9.5 GROUND WATER AND MARINE SEDIMENTS 95
9.6 OTHER ELEMENTS OF THE SELECTED REMEDY 9-5
9.6.1 Safety Measures 9-5
9.6.2 Integrating Cleanup With Land Use Plans 9-5
9.6.3 Periodic Review 9-6
9.7 CLEANUP SCHEDULE 9-6
9.8 COST OF THE SELECTED REMEDY 9-6
9.9 PERFORMANCE STANDARDS 9-6
10.0 STATUTORY DETERMINATIONS 10-1
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT 10-1
10.2 COMPLIANCE WITH ARARs 10-1
10.3 COST-EFFECTIVENESS 10-1
10.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT TECHNOLOGIES TO THE MAXIMUM EXTENT
PRACTICABLE 10-2
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT 10-3
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES 11-1
LIST OF TABLES
6-1. CONTAMINANTS OF CONCERN FOR SOIL, GROUND WATER AND AIR 6-3
6-2. CLEANUP OBJECTIVES 6-11
7-1. CLEANUP ALTERNATIVES 7-3
8-1. EPA'S NINE EVALUATION CRITERIA 8-2
8-2. COST 8-16
9-1. REMEDIATION GOALS FOR SURFACE WATER IMPACTING PUGET SOUND ... 9-12
9-2. PRELIMINARY REMEDIATION GOALS FOR CLASS III GROUND WATER
IMPACTING SURFACE WATER IN PUGET SOUND 9-13
B-1. INFORMATION REPOSITORIES B-3
B-2. LIST OF FACT SHEETS AND BROCHURES FOR THE
ASARCO TACOMA SMELTER SITE B-4
B-3. ARSENIC CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER
IN THE SOURCE AREAS B-7
B-4. COPPER CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER
IN THE SOURCE AREAS B-9
B-5. REASONABLE MAXIMUM EXPOSURE ASSUMPTIONS
FOR RESIDENTIAL USE B-11
B-6. SLOPE FACTORS FOR CANCER-CAUSING CHEMICALS B-12
B-7. REFERENCE DOSES FOR NON-CANCER CAUSING CHEMICALS B-13
B-8. ARARs ANALYSIS B-14
-------
LIST OF FIGURES
1-1. SMELTER SITE AND SLAG PENINSULA 1-3
6-1. AREAS OF SITE USED FOR THE EXPOSURE ASSESSMENT 6-6
7-1. EXAMPLE OF MULTI-LAYER SOIL CAP 7-4
7-2. HAZARDOUS WASTE OCF 7-5
7-3. EXAMPLE OF SHORELINE ARMORING 7-8
B-1. CANCER RISK BY LAND USE IN THE ARSENIC KITCHEN AREA B-1
B-2. NON-CANCER RISK BY LAND USE IN THE ARSENIC KITCHEN AREA B-2
APPENDICES
APPENDIX A: RESPONSIVENESS SUMMARY
APPENDIX B: FIGURES AND TABLES
APPENDIX C: SUMMARY OF ADDITIONAL SOIL TREATABILITY PILOT-PROJECT FINDINGS
APPENDIX D: ASARCO SMELTER SITE ON-SITE CONTAINMENT FACILITY EVALUATION
APPENDIX E: STATE DEPARTMENT OF ECOLOGY'S CONCURRENCE LETTER
APPENDIX F: ADMINISTRATIVE RECORD INDEX
in
-------
DECLARATION FOR THE RECORD OF DECISION
Site Name and Location
Commencement Bay Nearshore/Tideflats Superfund Site
Operable Unit 02 - Asarco Tacoma Smelter Facility and Slag Peninsula
Huston and Tacoma, Washington
Statement of Basis and Purpose
This decision document presents the selected remedial action for the former Asarco
Tacoma Smelter Facility and adjacent slag peninsula, in Ruston and Tacoma, Washington,
which was chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), as amended by the Superfund Amendments
and Reauthorization Act (SARA), and to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the
administrative record for this site. The State of Washington concurs with the selected
remedy.
This Record of Decision (ROD) describes the final cleanup remedy for soil, slag and
surface water and disposal of hazardous soils, demolition debris, and residential soils.
This ROD is intended to be an interim action for ground water.
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 or
substantial endangerment to public health, welfare, or the environment.
Description of the Selected Remedy
EPA has divided the Commencement Bay/Nearshore Tideflats Superfund site into seven
operable units (OUs) in order to facilitate the investigation, analysis, and cleanup of this
very large site. Four of these OUs are associated with the former Asarco smelter:
• OU 02 Asarco Tacoma Smelter and Slag Peninsula
• OU 04 Asarco Off-Property (Ruston/North Tacoma Study Area)
• OU 06 Asarco Sediments
• OU 07 Asarco Demolition
The remedy described in this ROD addresses OU 02 and involves the cleanup of metal
(e.g., arsenic, copper, lead) and organic contaminated soil, slag, and surface water and
IV
-------
ground water found at the former smelter facility and adjacent slag peninsula. This
remedy will address the principal threats posed by conditions at the Site, which are areas
that continue to act as the primary known sources (source areas) of contamination to
ground water and surface water that are flowing into Commencement Bay. The remedy
includes the following elements:
• Excavate source area soils and slag (approximately 160,000 cubic yards).
• Dispose of source area soils and demolition debris designated as hazardous
waste (approximately 240,000 cubic yards total) in an on-site containment facility
(OCF) that meets or exceeds regulatory standards for hazardous waste landfills.
• Cap the entire Site (plant site soils and slag and the slag peninsula). The low
permeability cap will be composed of layers of clean soils, gravel, and clay. The
contaminated residential soils excavated from the Ruston/North Tacoma Study
Area will be used as a sub-base for the cap.
• Demolish the remaining buildings and structures.
• Replace the entire surface water drainage system.
• Armor portions of the plant site and slag peninsula shoreline.
• Continue to monitor the surface water and ground water.
• Sample marine sediments.
• Develop and implement an enforceable program of restrictions and guidelines to
supplement the actual cleanup activities to ensure that the remedial action
remains protective and that development activities do not impact the long-term
effectiveness of the cleanup.
If it is determined that source control activities do not result in ground water that meets
federal and state standards, additional cleanup activities, if practicable, will be identified
in a separate ROD.
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 for this Site.
However, because treatment of the principal threats of the Site was found not to be
practicable, this remedy does not satisfy the statutory preference for treatment as a
principal element.
At this Site, EPA's determination that soil treatment was not practicable was based on
several factors, including the effectiveness of an OCF at isolating contaminated soils and
-------
debris from the environment, the community's stated preference during public comment
for on-site containment of contaminated waste, and the nearly $30 million difference in
cost between treatment and disposal of soil and disposal of soil without treatment in an
OCF.
Because the remedy will result in hazardous substances remaining on-site above health-
based levels, a review will be conducted no less often than every five years after
commencement of remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment.
Chuck Clarke Date
Regional Administrator
U.S. EPA Region 10
VI
-------
DECISION SUMMARY
Commencement Bay Nearshore/Tideflats Superfund Site
Asarco Tacoma Smelter Site
Operable Unit 02
Tacoma/Ruston, Washington
1.0 SITE DESCRIPTION
The Asarco Tacoma Smelter Superfund site ("Asarco Site" or the Site") is an operable unit (OU)
of the larger Commencement Bay Nearshore/Tideflats (CB N/T) Superfund site. The CB N/T
Superfund site was listed on the interim priority list by the U.S. Environmental Protection Agency
(EPA) in 1981, and included in the first published National Priorities List in September 1983. The
Site is located on the western shore of Commencement Bay and consists of 67 acres of property
owned by Asarco, Inc. and a 23 acre slag peninsula, home of the Tacoma Yacht Club. The Town
of Ruston, the City of Tacoma and the Metropolitan Park District are the three municipalities that
have zoning and permitting jurisdiction at this Site. This Record of Decision (ROD) addresses
contaminated soils, slag, demolition debris, surface water and ground water on the Site.
The general area of the former Asarco Smelter consists of steep slopes extending down to
Commencement Bay producing bluffs along portions of the shoreline. Many of the original
smelter buildings and structures were constructed on slag fill, which extended the existing
shoreline when molten slag from smelting operations was poured into Commencement Bay. A
car tunnel and railroad tunnel are located between the stack hill and the arsenic kitchen area.
Some dense vegetation exists on steep slopes (for example, the stack hill) and along the bluffs
above Commencement Bay, see Figure 1 -1.
The adjacent slag peninsula is composed of different forms of slag (molten or granulated) that
were poured or placed on many occasions between 1930 and 1970. Its primary surface features
are the Tacoma Yacht Club building, a paved access road, and paved parking areas. An
estimated 15 million tons of slag exist at the smelter property and slag peninsula.
Surface water features on the smelter property include surface water in the cooling pond and
south and east stack hill areas and a number of springs and seeps around the stack hill and
arsenic kitchen areas. Surface water drains into one of four drain systems and then into outfalls
at the Site called the city (owned by the City of Tacoma), north, middle, and south outfalls. The
latter three are owned by Asarco.
A complex pattern of ground water flows through or beneath the smelter property, including
through the slag, into Commencement Bay. Three primary groundwater aquifers (water bearing
zones) have been identified; two relatively shallow aquifers and one deep aquifer. A thick silt
barrier exists between the shallow and deep aquifers throughout much of the Site. Because of
the high degree of fractures in and porous nature of the slag, the tides bring seawater inland
several hundred feet where it mixes with ground water. The ground water within each of the
three aquifers is designated as either potential drinking water (Class IIB) or as non-potable water
(Class III). No one is currently drinking the ground water at or near the Site.
1-1
-------
Prior to 1890, a number of sawmills were active in the area and deposited wood waste along the
shoreline. From 1890 through 1912, the property was used as a lead smelter and refinery.
Asarco purchased the property in 1905 and converted it in 1912 into a facility to smelt and refine
copper from copper-bearing ores and concentrates shipped in from other locations. By-products
of the smelting operations were further refined to produce other marketable products, such as
arsenic, suifuric acid, liquid sulfur dioxide, and slag. Asarco ended operation of the smelter in
1985.
Metals were released into the soil, air, and Commencement Bay as a result of the smelting and
refining operations. Some examples of the metals present at the Site are arsenic, cadmium,
copper, lead, and zinc. Metals in slag or released into soil have migrated to surface and ground
water at the Site. Ores that were smelted at the Site have left metals in the buildings and
structures on the Site.
There are no listed Resource Conservation and Recovery Act (RCRA) wastes at the Site. In
several areas, contaminated soils are RCRA characteristic waste because they fail the Toxicity
Characteristic Leaching Procedure. Slag is not a RCRA waste under the Bevill exemption (40
C.F.R. §261.4).
There are no known floodplain zones or endangered species at this Site. There are several small
areas of the Site, other than the cooling pond, that have been identified as potential wetlands.
If these areas are confirmed as wetlands and if remediation occurs in these areas, the extent of
mitigation will be determined during remedial design.
1-2
-------
Marina
City Outfall
[orth
Outfall
Commencement Bay
COPPER REFINERY
AREA
'-^LJ
O
former
Stack
.Location
lOTHEAST
PLANT
DMA AREA
FIGURE
Key:
1-1: SMELTER SITE & SLAG PENINSULA
Source areas (identified source areas of
contamination to ground water)
Note: See Tables B-3 & B-4 in Appendix B for Soil and Class
Ground Water Concentrations
1-3
-------
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 HISTORICAL SITE ACTIVITIES
During the active industrial life of the Asarco Tacotna Smelter, the primary product was refined
copper. By-products of the copper smelting process included suffuric acid, liquid sulfur dioxide,
arsenic trioxide, arsenic metal, and copper reverbatory slag. The following is a brief
chronological summary of operations at the former Asarco Tacoma smelter.
1890 Began operation as a lead smelter under ownership of the Tacoma
Smelter Company.
1902 Copper production was started.
1905 Asarco purchased the smelter.
1917 Plant was rebuilt, stack was constructed, electrostatic precipitators were
added.
1930 Blast furnace smelting operations were discontinued and replaced with
reverberatories that produced slag as one by-product.
1974 A liquid sulfur dioxide plant began operation, using a dimethylaniline
process.
1977 A baghouse was installed to handle dust from the arsenic kitchen and
metallic arsenic plant.
1979 Electrolytic refinery ceased operation.
1985 Copper smelting operations were discontinued.
1986 Arsenic production was discontinued, and facility was taken completely out
of production.
As described above, much of the present facility is built over fill material, including slag, which
was placed by Asarco as part of the smelter operations. Since January 1987, Asarco has
completed two phases of demolition activities at the Site. Facilities in the stack area associated
with copper smelting and the production of both arsenic trioxide and metallic arsenic were
demolished in 1987-1988 during Phase I Site Stabilization. The majority of the remaining building
and structures, including the smelter stack, were demolished in 1992-1994 during Phase II Site
Stabilization. Much of the Site (where these facilities were located) has been leveled and, to a
minor extent, graded.
2.2 ENFORCEMENT ACTIVITIES
The history of regulatory activities affecting the former Asarco Tacoma Smelter began in the late
1960s with the passage of air emission standards by the Puget Sound Air Pollution Control
Authority (PSAPCA). EPA requirements such as National Pollution Discharge Elimination Systems
(NPDES) permits, which regulate point source water discharges, were applied in 1975.
Although PSAPCA began regulating sulfur dioxide and arsenic emissions in 1968, variances to
the standards were granted to Asarco until 1975. EPA began enforcement proceedings in the
early 1980s to regulate air emissions. Federal and state standards and variances continued to
be issues of contention until the smelter closed in 1985.
In July of 1983 EPA issued proposed standards for arsenic under Section 112 (National Emission
Standards for Hazardous Air Pollutants) of the Clean Air Act. Inorganic arsenic had been
2-1
-------
designated as a hazardous air pollutant in 1980 and the Asarco smelter was a major source of
arsenic. The proposed standard for Asarco, requiring hoods on the converters used in the
smelting process, was modified after public comment to require, in addition to the hoods, better
management practices in handling arsenic contaminated materials. These regulations were never
implemented due to a decision by Asarco to cease copper refining in 1985.
In September 1986, Asarco signed an Administrative Order on Consent (AOC) with EPA pursuant
to Section 106(a) of the Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA), in which Asarco agreed to conduct a Remedial Investigation and Feasibility Study
(RI/FS) and perform immediate site stabilization activities. Asarco's contractors began the RI/FS
in 1987 under EPA oversight. Site stabilization, Phase I and II, were both conducted based on
the information collected during the initial investigation of the Site.
In December 1990, EPA issued a ROD for demolition of structures and construction of a surface
water diversion system. Asarco agreed to perform this work in a consent decree dated May 18,
1992.
The field investigation and evaluation of remedial alternatives for a final RI/FS was concluded by
Asarco in January 1993 and was used to develop a final Site remedy.
In addition to the smelter property itself, Asarco is a responsible party for three closely related
OU of the CB N/T Superfund Site, known as Ruston/North Tacoma Study Area, Asarco
Sediments and Demolition. These units are reviewed below in the Section 4.0, "Scope and Role
of Operable Units."
The following is a brief chronological summary of enforcement activities associated with the
former Asarco Tacoma smarter.
1986 AOC for RI/FS and Phase I site stabilization signed.
1988 Phase I Site stabilization (demolition) activities completed.
1989 Draft RI/FS submitted.
1989 AOC for Expedited Response Action in Ruston/North Tacoma signed.
1990 Notice of Violation for RI/FS issued.
1990 Interim ROD for Phase II Site stabilization (demolition) and surface water
controls issued.
1991 Additional investigation of soils and groundwater contamination
commences.
1992 Notice of Violation resolved.
1992 Consent Decree for demolition entered in federal court.
1992 Fifth Amendment to the 1986 AOC revising the schedule for the draft and
final RI/FS submittals signed.1
1993 Two stipulated penalties for late draft FS submittals paid by Asarco.
1993 ROD for Ruston/North Tacoma Study Area issued.
1993 Unilateral Administrative Orderfor Ruston/North Tacoma Study Area issued.
1993 Final RI/FS reports for smelter cleanup submitted and approved.
1994 AOC for Ground Water, Surface Water, Soil and Marine Sediments
monitoring and sampling signed.
1 Amendments 1-4 for the AOC also included revised schedules for the performance of RI/FS work.
2-2
-------
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Throughout the studies leading up to this ROD, EPA has taken steps to inform and involve the
public about activities at the Asarco Smelter site. EPA conducted the activities summarized in
this section because the agency believes that community involvement in its decision making
process is a key element in developing a successful cleanup plan.
In addition to cleaning up contamination at the Asarco Site, the community is very interested in
the future use of the property. Although it is EPA's primary mission to design a cleanup plan that
protects public health and the environment, EPA believes this can be done with future
development of the Site in mind. Therefore, EPA has considered all comments related to the
future of the Asarco Site when selecting cleanup actions.
In order to provide a variety of opportunities for public participation in the cleanup decision
making process, EPA developed a communications strategy in 1993 for its activities related to
the Asarco Site. This strategy supplemented the existing Community Relations Plan, which
included all of the Commencement Bay Nearshore/Tideflats and South Tacoma Channel
Operable Units.
This section summarizes the outreach activities that EPA has conducted to date. In addition to
the activities discussed below, EPA has complied with the specific requirements for public
participation under CERCLA by publishing a Proposed Plan for public comment on August 12,
1994. The Proposed Plan was mailed to interested individuals and made available at local
information repositories (listed in Table B-1 in Appendix B). The original public comment period
ran from August 12 through October 11, 1994, and was extended until November 10 at the
request of interested citizens. During the comment period EPA held two public meetings, in
addition, a summary fact sheet was mailed to EPA's mailing list for the Asarco Site. EPA also
published newspaper advertisements in the Morning News Tribune to announce the availability
of the Proposed Plan, the comment period and the public meetings. Comments received during
the public comment period are summarized along with EPA's responses in the attached
Responsiveness Summary.
In addition to the public comment period, the following outreach activities were conducted by
EPA:
Small Group Meetings. EPA staff members have attended meetings with groups upon request
to share information about the agency's cleanup proposal, and to learn about different groups
concerns and needs for information about the Site. These groups include: Black Collective
Association; Izaak Walton League; Association of Builders and Contractors; Tacoma
Environmental Commission; National Association of Women In Construction; Association of
General Contractors; American Institute of Architects Southwest Washington; Environmental Task
Force of Tacoma-Pierce County Chamber of Commerce; Kiwanis Club and Rotary Club.
EPA staff will continue to meet with small groups as requested.
Community Interviews. In November 1993 EPA staff met with individual citizens to understand
better community concerns regarding cleanup.
3-1
-------
Availability Sessions. In October, November and December 1993, EPA and Asarco held sessions
where citizens could visit one-on-one with EPA and Asarco staff to discuss cleanup plans.
Community Workgroup Briefing. On May 19,1994, EPA held a meeting for the Ruston/North
Tacoma Community Workgroup. This workgroup was formed in 1989 to provide an avenue for
citizens to become involved in residential investigation and cleanup activities. EPA presented a
preview of its Preferred Cleanup Alternative at the meeting in order to get feedback and
comments from the group.
Public Meetings. EPA held two public meetings during the 90-day public comment period on the
Proposed Plan. At the meetings participants learned more about EPA's Proposed Plan and had
the opportunity to provide public comments. Transcripts were taken of these two meetings (held
August 30 and September 19,1994) and are available in EPA's Administrative Record for the site.
Periodic Briefings. Briefings have been held for the Town of Ruston, City of Tacoma, Tacoma
Environmental Commission, Congressman Dicks' Office and other interested local government
officials.
Information Repositories. EPA has established and updates ten repositories where citizens can
review detailed information about EPA's Superfund activities. New materials are periodically
added to these repositories. Documents subject to public comment can also be found in these
locations. The repositories are frequently advertised in fact sheets and in newspaper notices
prepared by EPA.
Fact Sheets and Brochures. EPA prepares regular fact sheets for distribution to members of the
community to provide current information on the status of site activities. Table B-2 in Appendix
B, identifies a list of fact sheets and brochures published about the Asarco Site prior to this
ROD.2
Coordinating Forum. In July of 1993, the Ruston/North Tacoma Coordinating Forum turned its
attention to evaluating cleanup options for the Asarco Tacoma Smelter. The group was originally
formed in March 1991 to facilitate discussion and coordination among the various entities
involved and/or affected by the Ruston/North Tacoma Residential Study Area project.
In order to address issues associated with cleanup and future redevelopment of the Asarco
smelter, the group formed two subcommittees: 1) land use, and 2) technical. The two
committees worked for over a year on issues related to developing a cleanup plan for the smelter
site. EPA participated directly in the technical subcommittee and received input from the land
use committee. Input from both of these committees was instrumental to EPA in developing the
Proposed Plan, which was published in August 1994. The following parties participated in the
Forum subcommittees:
Land Use Subcommittee*:
Asarco
City of Tacoma
Metropolitan Parks District
2 Fact sheets devoted exclusively to demolition activities are not included in this list
3-2
-------
Town of Ruston
* All land use subcommittee members were also represented on the technical committee.
Technical Subcommittee:
Agency for Toxic Substances and Disease Registry
Citizens for a Healthy Bay
Community Representative
Environmental Protection Agency
Puget Sound Air Pollution Control Authority
Puyallup Tribe of Indians
Tacoma-Pierce County Health Department
U.S. and State Fish and Wildlife Services
Washington Department of Ecology
Washington Department of Health
Washington Environmental Council
Technical Assistance Grant. In 1991 EPA awarded a Technical Assistance Grant (TAG) to the
Citizens For A Healthy Bay. Citizens For A Healthy Bay have used these funds to have technical
experts review and comment on cleanup design documents, prepare information for the general
public on cleanup work, and prepare information for non-English speaking people who may fish
or work on Commencement Bay. They have an office in downtown Tacoma which is open to
the public and serves as an information repository for the Commencement Bay and Asarco
Superfund sites. They also publish a quarterly newsletter which covers a wide-range on
environmental issues associated with Tacoma.
3-3
-------
4.0 SCOPE AND ROLE OF OPERABLE UNITS
Superfund response activities at the CB N/T Site currently are coordinated under seven separate
OUs. Four of the OUs are related to the Asarco Superfund project. They are:
OU 02 - Asarco Tacoma Smelter
OU 04 - Asarco Off-Property (Ruston/North Tacoma)
OU 06 - Asarco Sediments
OU 07 - Asarco Demolition
The remedy described in this ROD addresses cleanup of OU 02, the Asarco Tacoma Smelter.
It primarily involves the cleanup of metal-contaminated soils, slag, surface water and ground
water. It also addresses the final disposal of demolition .debris, the Expedited Response Action
(ERA) soils and the Ruston/North Tacoma residential soils.
4.1 SCOPE OF CURRENT WORK
4.1.1 OU O2 - Asarco Tacoma Smelter
Based on its evaluation of human health and ecological risks associated with existing conditions
at the Asarco Site, EPA believes that current conditions on the Asarco Site pose unacceptable
risks over the long-term to future potential workers, residents and visitors, and to the ground
water discharging to Commencement Bay. Therefore, cleanup actions are necessary. EPA's
goal is to reduce potential exposures to metal and organic contaminants by removing
contaminated soils that act as source areas to the surface water and ground water, by capping
the Site (soil and slag) surfaces and by armoring the slag shoreline. Soil removal or capping
contaminated soils and slag is expected to reduce the contaminants that are carried into
Commencement Bay by surface water and/or ground water and prevent direct contact with the
soil and slag by humans and animals.
This ROD describes the final cleanup remedy for soil, slag and surface water and disposal of
hazardous soils, demolition debris and residential soils. This ROD is intended to be an interim
action for ground water.
Site Development Planning
Concurrent with EPA's efforts to design a cleanup plan, Asarco, the Town of Ruston, the City of
Tacoma, and the Metropolitan Park District formed a "land use committee" and hired consultants
to help the group develop a Master Use Plan for future development of the Site after cleanup.
This effort involved significant citizen participation. Asarco and the land use committee held four
week-long public forums called "Asarco Weeks" over an eight-month period to solicit ideas
regarding the future use of the Asarco property. These efforts resulted in an "Agreement in
Principle," negotiated by Asarco, the City of Tacoma, the Town of Ruston, and the Metropolitan
Park District of Tacoma, that outlines a proposal for development of the Asarco Site, including
responsibilities among the signatories for such development.
The "Agreement in Principle" adopts the "G-2.1" concept, the consensus approach resulting from
the Asarco Weeks, and provides general guidelines for open space and development zones,
4-1
-------
such as commercial, residential, recreational, marine, and mixed uses, and for surface roadways.
The G-2.1 concept provides for a park centered on the Site with a setback traffic center and a
crescent-shaped development area fronting on grassy areas facing Commencement Bay. The
park would extend from Huston Way to Point Defiance Park.
Although the "Agreement in Principle" and this ROD are separate documents, they contain some
common elements. They are separate because they represent different objectives and types of
decisions regarding the smelter property. The purpose of the ROD is to document EPA's
cleanup decision for the Site. Under the Superfund law, EPA has the authority to select and
implement cleanup actions. In contrast, the "Agreement in Principle" outlines a proposal for
development of the property after cleanup. The property owners, Asarco and the Park District,
and the local governments with jurisdiction over the property, Tacoma and Ruston, have the
authority to determine how the property can be used in the future after the cleanup has been
completed.
4.2 OTHER RELATED ACTIVITIES
4.2.1 OU O4 - Asarco Off-Property (Ruston/North Tacoma Study Area)
The initial action for the Ruston/North Tacoma Study Area was an ERA. In March 1989, Asarco
and EPA entered into an agreement for Asarco to conduct the ERA in the Ruston/North Tacoma
Study Area. The AOC issued under Section 106(a) of CERCLA, required Asarco to clean up and
cap 11 publicly accessible properties in Ruston. Contaminated soils excavated from all of the
properties are stored temporarily at the Site in a building known as the line ore bins building."
In June 1993, EPA issued a ROD requiring that arsenic and lead contaminated soils in residential
yards and in public right of ways surrounding the former smelter facility be excavated or capped
and disposed off-site. In November 1993, an Explanation of Significant Difference (ESD) was
available for public comment and was subsequently signed by EPA, allowing for temporary
storage of the Ruston/North Tacoma residential soils on the north end of the former smelter
property. The ESD provided for these soils to be left on the former smelter site until either the
final Site remedy was selected or until December 31, 1994. EPA issued a Fact Sheet in
December 1994 stating that, in general, the community supported disposing these soils on site
as a sub-base for a cap and that these soils would remain on site until the final smelter remedy
was selected. By the end of 1994,75 private properties had been cleaned up and 269 yards had
been sampled.
4.2.2 OU O6 - Asarco Sediments
EPA issued a Supplemental Feasibility Study for the off-shore sediments in summer 1993.
However, EPA, Ecology, Asarco, the Natural Resource Trustees and a community group believed
that additional investigations and evaluation of the cleanup actions were necessary. In 1994,
Asarco and EPA entered into an AOC requiring Asarco to collect and evaluate additional
information regarding the off-shore marine sediments.
4.2.3 OU O7 - Demolition and Surface Water Controls
in November 1994, Asarco completed Phase II demolition of remaining Site structures under a
federal Consent Decree signed in 1991 with EPA. Also under the Consent Decree, Asarco
4-2
-------
controls surface water that runs onto the Site to minimize the contact of surface water with
contaminated soil in the cooling pond.
The remainder of this ROD discusses only the source control activities for cleanup of OU 02, the
former Asarco Smelter, and the final disposal of demolition debris, the ERA soils and the
Ruston/North Tacoma residential soils.
4-3
-------
5.0 SUMMARY OF SITE CHARACTERISTICS
Under EPA's oversight, Asarco collected and analyzed soil, slag, surface and ground water, and
sediment samples at the Site.
Soil. The following contaminants were found in soils on the Site at levels that were of potential
concern to human health and the environment:
Metals
Antimony, Arsenic, Cadmium, Copper, Lead, Mercury, Silver, Thallium, Zinc
Organic Chemicals
Polyaromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs)
These contaminants in soil are of concern because (1) they are the primary source of
contamination to ground water and surface water that is flowing into Commencement Bay; and
(2) they are a potential health concern for humans and animal life that be exposed to the
contaminants in the soil now or in the future.
Samples show that the principal threats to human health and the environment posed by the
Asarco Site are the contaminated materials in the six "source areas" identified on Figure 1-1.
These are areas that have either the highest measured concentrations of contaminants in the
soils, appear to act as the primary known sources of contamination to ground water and surface
water, and/or have large amounts of contaminated material based upon the historic uses of these
areas.3 These areas are the:
• Stack Hill • Copper Refinery Area
• Cooling Pond • Fine Ore Bins Building
• Arsenic Kitchen • Southeast Area of the Plant
Soil and groundwater concentrations in the source areas are identified for both arsenic and
copper in Tables B-3 and B-4, respectively, in Appendix B.
In addition to these six areas, elevated concentrations of metals were detected in soils and slag
throughout the entire property. Even though certain areas are not considered principal threats
to ground water, the concentrations generally are high enough throughout the Site to pose a
threat if they are inhaled, ingested, or touched by people or animals.
Slag contains high concentrations of metals, including arsenic and lead, in a rock-like form.
Concentrations of arsenic found in slag ranged from 100 to 24,950 ppm. The slag along the
smelter shoreline is a poured matrix. The slag found on the slag peninsula is primarily fine
grained, sand-like particles. The slag portions on the Site appear to contribute less
3 For example, the highest concentration of arsenic found in soil is 403,100 parts per million (ppm) near the arsenic
kitchen area. This level is approximately 130 times higher than the highest concentration found in Ruston. The highest
concentration of arsenic in ground water is located in monitoring well 111 with 52 ppm (.006 parts per million is EPA's
preliminary remedial action objective). This monitoring well is down-gradient from the arsenic kitchen and fine ore bins
area. See Table 3 for maximum concentrations of chemicals of concern.
5-1
-------
contamination to ground water than the source areas described above. Slag poses a threat if
ingested by people or animals. In addition, the fine slag particles on the peninsula are blown into
Commencement Bay and potentially into the recreational areas of the Yacht Basin and Point
Defiance Park.
"Hie face of the slag shoreline appears to be impacted by the tidal activity in Commencement
Bay. High energy currents and wave action cause erosion of the slag, which results in slag
particles moving from the shoreline and being deposited into the off-shore sediments. Recently,
a shoreline monitoring station was washed away.
Surface water samples were collected from seeps (ground water that surfaces from hillsides or
in the tunnel), puddles, and at the outfalls that discharge into Commencement Bay. Asarco
found that surface water on the Site, including seeps and small stagnant pools below the stack
hill and in the arsenic kitchen area, and water in the cooling pond, is contaminated with metals
at levels higher than federal or state standards for drinking water and for protection of sea life.
The contaminants that exceed regulatory levels include arsenic, beryllium, cadmium, chromium,
copper, lead, mercury, nickel selenium, silver zinc, total petroleum hydrocarbons, and anilines.
The surface water investigation showed that the surface water drainage system on the Site is no
longer adequate. The pipes and drains associated with the system may be cracked and/or the
pipes filled with contaminated sediments. Surface water can become contaminated by contact
with the contaminated sediments in the pipes. The contaminated surface water can then leak
out of the system and migrate to ground water or discharge to Commencement Bay.
Ground Water. Three water-bearing zones (groundwater aquifers) were identified at the smelter
property. The two shallowest aquifers, the slag and marine sands aquifers, show elevated levels
of arsenic, copper, zinc, and other metals. A thick sift barrier between the shallow and deeper
aquifers seems to have protected the deeper aquifer, the Pre-Vashon aquifer, from contamination.
Only a few water samples from the deeper aquifer have elevated metal concentrations. The few
exceptions may result from contamination migrating through a production well, which was drilled
into the deeper aquifer during the smelter's operation. This well has now been plugged so that
contamination is unlikely to continue migrating from this well into the deeper aquifer.
The three primary ways for metals to move into ground water are: (1) clean or contaminated
surface water moving through contaminated soil into ground water; (2) contact between ground
water and soil or slag that releases metals into ground water; and (3) leakage and spills, for
example, from former process operations such as ore handling, storage, or refining, and from the
existing sewer and drainage system.
Organic contamination caused by dimethylaniline (DMA) that was used in the production of
sulfuric acid has been identified in the southeast corner of the smelter property. Wood debris
and sawdust, left over from sawmill operations and now buried beneath the slag, are
decomposing thus contributing to the release of metals, particularly arsenic, from the slag into
ground water and Commencement Bay.
The metal levels in ground water decrease as ground water moves through the smelter property
towards Commencement Bay. This decrease in contamination may be due to: (1) seawater or
groundwater dilution; (2) metals adhering to the slag as ground water moves towards the bay;
(3) metals being removed from the ground water through chemical reactions; or (4) the
contaminant plume moving slowly through the smelter property.
5-2
-------
The contaminants that exceed regulatory levels for ground water entering the bay are: arsenic,
beryllium, cadmium, copper, lead, mercury, nickel, selenium, silver, zinc, total petroleum
hydrocarbons, and anilines.
Air. Samples of dust were collected at 22 smelter property locations. A model was used to
predict how much dust would move into the communities of Huston and Tacoma if there were
no cleanup. The results showed that the highest emissions would be on the smelter property
and that emission levels decrease rapidly with distance from the smelter property.
5-3
-------
6.0 DESCRIPTION OF SITE RISKS
This section of the ROD provides a brief summary of the "On-Property Human Health Risk
Assessment' ("Risk Assessment") for the Asarco Tacoma Plant (Kleinfelder 1993). The document
was prepared by Asarco, with EPA oversight, to assess the potential human heath risks from Site
contamination and was completed according to national and regional EPA risk assessment
guidelines. It evaluates potential risks from exposure to contamination in soil, slag, surface
water, ground water and air if no remedial action is taken on the Site. The results of this
assessment were used to decide whether remedial action is appropriate and which
exposure pathways and contaminants require remediation.
^ ;-• •>
^VT," , .••.. *. . - *•?» •;'•». \ -..j^"-? fr^J\/Z",T F£Tfe> ••"••\ia '' "•''
vt.ifevi^5s«:p6®t^
•''''jfft/ivte ^n »ri*ii-| _ - m BUJ i -.-BV •!»• • i.T»iaii,y|^^»MT' .-ir*r,- -iHvir^f. fu^^ffy ,. v
st^stetrtiaffy exceede^A's water quaftyafteriaf^^ ;
and
A detaSeddtscussaon of
;leairta^
ptkms^^ffi^^^
.impacte sesociated with each pathway .oars;i» fc>ww( lr| ^e;f5telc
Assessnwnt report .. - ; ' ",.
Risk assessments are performed using information on the toxicity of contaminants and
assumptions regarding the extent to which people may be exposed to them. This summary of
the Asarco Risk Assessment is divided into five sections: (6.1) identification of contaminants of
concern (COCs), (6.2) exposure assessment, (6.3) toxicity assessment, (6.4) risk characterization,
6-1
-------
which is an integration and summary of the information gathered and analyzed in the preceding
sections, and (6.5) analysis of the uncertainty involved in developing a risk assessment. In
addition, Section 6.6 is a summary of the qualitative ecological risk assessment (EPA 1993).
6.1 IDENTIFICATION OF CONTAMINANTS OF CONCERN (SCREENING ANALYSIS)
The selection of chemicals that potentially contribute to risks to human health at the Site, known
as the COCs, was a two-step process. First a screening evaluation was done comparing the
maximum chemical concentrations in soil, ground water, and air with conservative health-based
concentrations and/or with appropriate criteria and standards. The chemicals selected in this first
step were then evaluated, taking into account each chemical's frequency of detection, toxicity,
persistence and mobility, in order to select the final COCs in each media. These are shown in
Table 6-1.
Chemicals selected for soils, Class IIB ground water (potential drinking water) and air shown in
Table 6-1 were selected using exposure parameters based on residential use of the Site.
Water from Class III wells is not suitable for drinking, it contains contaminants and can migrate
into the bay. The COCs for Class III ground water were selected based upon the potential for
humans to be exposed to these contaminants through consumption of seafood from the bay.
Five metals were selected: arsenic, beryllium, lead, manganese and mercury.
All of the metals selected as COCs in ground water and soil were selected as COCs in surface
water. Arsenic and lead were selected as COCs of concern in slag based upon information from
the Ruston/North Tacoma Risk Assessment.
6.2 EXPOSURE ASSESSMENT
The exposure assessment estimates the type and magnitude of exposures to the COCs at the
Site. It considers the current and potential future uses of the site, characterizes the potentially
exposed populations, identifies the important exposure pathways and quantifies the intake of
each COC from each medium for each population at risk. The result of the assessment is a
calculated daily dose of each COC per body weight for each exposure medium.
6.2.1 Identification of Site Uses, Exposed Populations and Exposure Pathways
Site Use Scenarios. The exposure assessment for the Asarco Site considers five land-use
scenarios involving different groups of potentially exposed populations. Of the five land-use
scenarios considered, one represents the current use or "non-use," and four represent projected
future uses: residential, commercial, heavy industrial, and recreational.
Potentially Exposed Populations. Each scenario described above has an associated
population that may be exposed to COCs at the site. The populations assumed for each of the
site uses are described below.
(1) Non-Use. Currently, the Site is not being used for any purpose other than for site
investigation, monitoring and demolition. For this existing use scenario, potentially
exposed populations are maintenance workers, guards, trespassers and nearby residents
who may be exposed to dust from the Site.
6-2
-------
TABLE 6-1. CONTAMINANTS OF CONCERN FOR SOIL, GROUND WATER AND AIR
Ground
water
Drinking Impacting
Chemical Soil Water the Bay Air
*\ «?•''.
Lead
Mercury
N
Selenium
SBver
-H
fl
Polycydtc AromaSc Hfydrocafbons
Aniline CompoumJs C
C Cancer Causing Chemical
N Chemical Causing Non-Cancer Health Effects
C/N Chemical Causing Both Cancer and Non-Cancer Effect
G
6-3
-------
(2) Residential. The Site would be developed for residential use. People would spend 30
years of their lifetime on the Site.
(3) Heaw Industrial. The Site would be developed for industrial purposes. Workers would
spend 25 years of continuous employment at the Site.
(4) Recreational or Park. All or part of the Site would be developed as a park. Visiting
children and adults would be exposed to Site contaminants.
(5) Commercial. Part or all of the Site would be redeveloped for commercial uses including
office buildings and shops. Office workers and merchants would be the primary exposed
populations.
Exposure Pathways. An exposure pathway is the mechanism by which chemicals migrate from
their source or point of release to the population at risk. Four elements comprise a complete
exposure pathway: (1) a source of a chemical release (e.g., contaminated soils); (2) movement
of contaminants through environmental media (e.g., rain moving through contaminated soil into
ground water); (3) a point of potential human contact with a contaminated medium (e.g., use of
contaminated ground water for drinking water); and (4) entry into the body or exposure route
(e.g., ingestion of drinking water).
The exposure pathways considered for the Risk Assessment varied depending on the land use
being considered and on the population potentially exposed. For example, in assuming future
residential land use of the Site, the following exposures were evaluated for adults and children:
(1) ingestion of slag, soil, and dust; (2) dermal exposure to soil and dust; (3) ingestion of
vegetables potentially contaminated by soil contaminants; (4) inhalation of contaminants in the
air as a result of dust resuspension from the site; (5) ingestion of potable ground water on the
Site; and (6) ingestion of contaminated surface water in pools and seeps on the Site.
In contrast, the potential exposures considered for a site maintenance worker under the current
non-use scenario were: (1) ingestion of soil, dust, and slag; (2) dermal exposure to soil and
dust; and (3) inhalation of contaminants in dust.
6.2.2 Calculation of Exposure
EPA's Superfund guidance requires that the reasonable maximum exposure (RME) be used to
calculate potential health impacts at Superfund sites. The RME is the highest exposure that is
reasonably expected to occur at the site. It is calculated using conservative assumptions in order
to represent exposures that are both reasonable and protective. In the Risk Assessment, RMEs
were estimated for the land-use scenarios and exposure pathways described above (see
Table B-5 in Appendix B for the RME exposure assumptions for potential residential use). For
the residential scenario, average exposures were calculated in addition to the RMEs to represent
exposures of a more typical person.
To estimate exposure, data on the concentrations of COCs in the media of concern at the Site
(the exposure point concentrations) are combined with information about the projected behaviors
and characteristics of the people who may potentially be exposed to these media (exposure
parameters). These elements of the Asarco Site are described below.
6-4
-------
Exposure Point Concentrations: The Site was divided into six areas to calculate the
contaminant levels for estimating exposure because the Site is large, the types and
concentrations of contaminants vary by area, and there are several possible future land-use
scenarios, see Figure 6-1. The areas are (1) the administrative area; (2) arsenic kitchen area; (3)
cooling pond area; (4) stack hill area; (5) off-plant area; and (6) general plant slag area. Section
3.0 of the Risk Assessment presents details on the calculations and use of these exposure point
concentrations.
Exposure Parameters: The parameters used to calculate the RME include body weight, age,
contact rate, frequency of exposure and exposure duration. Exposure parameters provided in
EPA Superfund guidance were used when available (i.e., for the residential and heavy industrial
land uses). Parameters for the other land uses were developed for the Asarco Site using best
professional judgement.
For all of the media, except surface water, exposures were estimated assuming long-term
exposures to site contaminants (e.g., 30 years of daily use for residential use, 350 days/year, and
25 years, 8 hours/day for 5 days/week, for heavy industrial use). Potential risk from surface water
was calculated assuming that a child accidently consumes water that has puddled on the Site.
Since there were no data on contaminant levels in Commencement Bay for fish, potential risks
from the consumption of fish and shellfish were estimated by comparing the levels of
contaminants in selected shoreline wells with EPA's WQC for protection of human health from
fish consumption.
6.3 TOXICITY ASSESSMENT
The purpose of the toxicity assessment is to provide, where possible, an estimate of the
relationship between the extent of exposure to a contaminant and the increased likelihood and/or
severity of adverse effects. This is done by weighing available evidence regarding the potential
for particular contaminants to cause adverse effects in exposed individuals.
EPA has conducted toxicity assessments for many chemicals and publishes the resulting values,
slope factors (Sfs) and reference doses (RfDs), on the Integrated Risk Information System (IRIS)
or in the Health Effects Assessment Summary Tables (HEAST). With the exception of lead, which
is assessed using the integrated uptake/biokinetic model (IUBK) developed by EPA, IRIS and
HEAST were used as a source for Sfs and RfDs.
Sfs have been developed for estimating upper-bound excess lifetime cancer risks associated with
exposure to potential cancer-causing chemicals. They are expressed in units of the inverse of
milligrams per kilogram of body weight per day (mg/kg-day)*1. Sfs are derived from the results
of human epidemiological studies or chronic animal bioassays to which mathematical
extrapolations from high to low dose and from animal to human have been applied, see Table
B-6 in Appendix B.
6-5
-------
COOLING POND
AREA #3
Commencement Bay
PLANT
IVDMINISTRATIO
AREA
ARSENIC KITCHEN
AREA
Former
Stack
Location
o
OFF-
PLANT
AREA #5
South Outfall
STACK
AREA #4
FIGURE 6-1: AREAS OF SITE USED FOR EXPOSURE ASSESSMENT
6-6
-------
RfDs have been developed to indicate the potential for adverse hearth effects from ingestion of
COCs that exhibit non-cancer effects, such as damage to organ systems (e.g., the nervous
system, blood forming system, etc.) and learning disabilities. They are expressed in units of
mg/kg-per day. RfDs are estimates within an order of magnitude, of lifetime daily exposure levels
for people, including sensitive individuals, that are likely to be without risk of adverse effect.
Estimated contact with contaminant(s) of concern from environmental media can be compared
to the RfD (e.g., the amount of a contaminant(s) of concern ingested from drinking water or soil
in mg/kg/day). Reference concentrations (RfCs) are used to indicate potential non-cancer health
impacts from inhalation (usually expressed in milligram per cubic meter), see Table B-7 in
Appendix B.
The standard non-cancer risk assessment method described above was not used for the
assessment of lead in soil. For the residential scenario, EPA guidelines specify the use of the
IUBK model for estimating acceptable lead levels in soil. EPA guidance recommends that soil
lead concentrations should be low enough to ensure that blood lead levels do not exceed 10
micrograms per deciliter in 95% of the potentially exposed children. The IUBK model predicts
a value of 500 ppm of lead in soil to meet this goal. The exposure point concentrations
calculated for lead in soil at the Site were compared to this value of 500 ppm to assess its
potential non-cancer impacts.4
6.4 RISK CHARACTERIZATION
Risk characterization is an integration and summary of the information gathered and analyzed
in the preceding sections. Site-specific exposure estimates were combined with cancer Sfs and
RfDs to assess potential health impacts.
To estimate cancer risk, the Sf is multiplied by the exposure expected for that chemical to provide
an upper-bound estimate of the excess lifetime cancer risk. This estimate is the incremental
probability of an individual developing cancer over a lifetime as a result of exposure to cancer-
causing chemicals at a site.
The potential for non-cancer health impacts is evaluated by dividing the exposures calculated for
each COC at the site by its RfD or RfC. The result is the Hazard Quotient (HQ). By adding the
HQs for all contaminants via one exposure pathway, the HI is calculated.
The results of the Risk Assessment show that the estimated cancer and non-cancer impacts from
exposure to Site contaminants in soil vary with the Site areas and with the projected future land-
use. The estimated lifetime cancer risk from ingesting soil in the arsenic kitchen area, assuming
residential land use, may be up to two chances in ten (2 in 10). Cancer risks in the other five
areas of the Site, assuming residential land use, range from about 4 chances in 100 to 2 chances
in a 1,000. These risks are lower primarily because contaminant levels are high in the arsenic
kitchen area than in the rest of the Site.
Residential exposure to soils in the arsenic kitchen area is estimated to result in an excess
cancer risk of 2 chances in 10, but the risks for the other possible site-uses (industrial,
commercial, recreational and non-use) in the arsenic kitchen area range from 5 chances in 100
4 Since the Risk Assessment was completed, the IUBK model has been revised. The most recent version of the
IUBK model results in lead levels of 400 ppm. EPA does not believe that this significantly alters any of the conclusions
in the Risk Assessment and does not have an impact upon any Site cleanup decisions.
6-7
-------
to 2 chances in 1,000. Residential use assumptions result in the highest risks because
exposures occur more often and over longer periods of time, more exposure routes are possible
and children have higher exposures than adults.
Cancer risks vary by route of exposure. For example, for residential exposures in the arsenic
kitchen area, ingestion of soil contaminants results in the highest cancer risk (2 chances in 10)
followed by exposure to contaminants in drinking water (about 4 chances in 100), eating
vegetables (3 chances in 1,000), inhaling contaminants in dust (5 chances in 10,000) and dermal
exposure to soils (5 chances in 100,000), see Figure B-1 in Appendix B.
According to the National Contingency Plan, which governs Superfund cleanup, if the cumulative
cancer risk on a site is greater than approximately 1 in 10,000, a cleanup action is generally
taken.
The estimated HI, which is used to evaluate non-cancer impacts, is 806 in the arsenic kitchen
area assuming soil ingestion and residential land-use. His in this area for other land uses range
from 7 to 205, see Figure B-2 in Appendix B. The HI for groundwater ingestion in the arsenic
kitchen area assuming residential land use is 219. His above 1 are used in the Superfund
program to indicate that site remediation may be necessary.
Arsenic is responsible for the majority of the cancer risk at the Site. Several metals, including
arsenic, lead, and copper are responsible for the non-cancer impacts at the Site.
Exposures to arsenic, copper and lead in site surface water may result in acute hazard to
children who swallow this surface water. The concentrations of four metals, arsenic, mercury,
manganese and beryllium, in Class HI ground water near the bay are in excess (above a 1 in
10,000 cancer risk or above RfDs) of EPA's water quality criteria for protection of human health
from fish consumption. Aniline is in Class III ground water at concentrations that exceed a risk
of 1 in 10,000 assuming fish consumption.
Although the Risk Assessment did not include an evaluation on the adjacent slag peninsula,
potential health impacts in this area are expected to be similar to those in Area 6, the general
plant slag area. Area 6 was evaluated in the Risk Assessment for arsenic exposure. Assuming
residential exposures, cancer risk in Area 6 may be as high as 2 in 1,000 and the HI is above 1.
Therefore, both the slag peninsula and the general plant slag area contain arsenic at levels that
may result in cancer and non-cancer risks above Superfund levels of concern.
6.5 UNCERTAINTY ANALYSIS
The numerical results of a risk assessment (HQs and cancer risk values) are uncertain because
of limitations in knowledge regarding exposure and toxicity. Where information is incomplete,
assumptions must be made: the greater the uncertainty, the more conservative the assumptions
to be protective of public health. Even when actual characteristics of a population are known,
selected exposure parameters are biased toward over-estimating rather than under-estimating
risk for the majority of the population. A discussion is presented below on how uncertainties in
the risk assessment process might overestimate or underestimate risk.
Some of the factors that may lead to a possible overestimation of risk are as follows:
6-8
-------
(1) The majority of the soil samples were collected in areas of the Site thought to be
contaminated based on past smelter operations, so the whole Site might not be as
contaminated as these samples indicate;
(2) Because of a lack of information, the exposure parameters (e.g., exposure frequency and
duration) used in the risk assessment are derived in a conservative manner;
(3) EPA assumes that there is a cancer risk associated with all exposures to cancer causing
chemicals and that this risk increases as exposure increases. This assumption may not
be true for all carcinogens;
(4) RfDs are developed from animal data using uncertainty factors to take into account the
differences between animals and people and the differences in experimental versus
environmental exposures. For some chemicals, these uncertainty factors may be overly
conservative.
Conversely, there are factors that may lead to a possible underestimation of risk. Some of these
factors are as follows:
(1) Some of the unsampled areas of the site may have higher concentrations than those
areas sampled;
(2) Soil exposure assumptions were made using surface soil concentrations; some
subsurface soils on the Site have contaminant levels that are higher;
(3) The lack of data available for the derivation of exposure factors and toxicrty factors (Sfs
and RfDs) could result in factors that are too low, although the use of uncertainty factors
makes this unlikely;
(4) Estimated cancer risks for arsenic, which is the contaminant of greatest concern at the
Site, may be too low. They were evaluated using the Sf in the IRIS data base, which takes
into account only arsenic's ability to cause skin cancer although more recent analyses
have shown that arsenic ingestion can also elevate risks of internal organ cancers; and
(5) Contribution of site contaminants to fish ingestion exposure by surface water run-off,
outfalls, sediments or existing contaminants in the Bay from past Site discharges were not
evaluated.
For more detail regarding uncertainty, see Section 6.0 of the Risk Assessment.
6.5.1 Comparison of the Risk Assessment Results to Superfund Regulations and Guidance
The results of the Risk Assessment are evaluated to determine if the Site needs to be cleaned
up and what cleanup actions are warranted. This evaluation is made by determining whether the
cancer risks and the non-cancer health impacts exceed those considered to be of concern to
EPA's Superfund program as defined in EPA's National Contingency Plan (NCP) and "Role of the
Baseline Risk Assessment in Superfund Remedy Selection Decisions," April 22,1991, OSWER
Directive No.9355.0-30.
6-9
-------
Where the cumulative carcinogenic site risk to an individual based on RME for both current and
future land use is less than approximately one in ten-thousand, and the non-cancer causing HQ
is less than 1, cleanup on a site is generally not warranted unless there are adverse
environmental impacts. As described above in the risk characterization section, the cancer risks
and His calculated were in excess of these two criteria. Based on the results of the Risk
Assessment, EPA has determined that cleanup is necessary at the Site.
6.6 ECOLOGICAL RISK ASSESSMENT
EPA developed an Ecological Risk Assessment to assess the impacts of contamination on sea
life, plants and pets. EPA based its assessment on available literature and Site-related data. The
assessment suggests that the metals in soils may have an impact Site vegetation. Based on
exceedances of federal and state water quality criteria in ground water and surface water and
exceedances of state sediment quality criteria in off-shore sediments, sea life in the off-shore
sediments have been adversely affected by releases from the Site.
6.7 ERA'S CLEANUP OBJECTIVES AND TWO-PHASE APPROACH
Cleanup actions are necessary because current conditions at the smelter property and on the
slag peninsula pose unacceptable long-term risks for current workers, possible future visitors or
residents, and sea life and animals. EPA is recommending a comprehensive cleanup strategy
in order to address the multiple sources of contamination at the smelter property and slag
peninsula. EPA's objectives for the cleanup are identified in Table 6-2. The performance
standards .for the selected remedy are found in Section 9.
EPA will accomplish its cleanup objectives at the smelter property and slag peninsula in two
phases. The first phase, which is described in this ROD, includes activities to control continuing
sources of contamination at the smelter property and slag peninsula. These "source control"
activities will remove or control portions of the property that are known to be contributing to the
contamination of surface water and ground water. Such activities will also minimize possible
exposure to contamination via direct contact, and therefore further reduce Site risks.
The second phase could include additional active clean up measures, if necessary, to restore
surface water or groundwater quality and will be described in a subsequent ROD. An example
of an active measure would be installing a groundwater pump and treat system at the Site.
Further active measures would not be necessary if ground water or surface water clean up levels
are achieved as a result of the source control measures. In this case, a "no-action" ROD would
be issued.
6-10
-------
TABLE 6-2. CLEANUP OBJECTIVES
CONTAMINATED SOIL, DUST AND SLAG
(a)
(b)
(c)
Prevent ingestion and inhalation of contaminated soils slag and dust containing
contaminants in concentrations above applicable or relevant and appropriate
requirements (ARARs) or above risk-based goals when ARARs are not available
or protective;
Reduce releases of contaminants from soil to ground water by:
Removing the source areas where contaminants leach from soil to
ground water
Limiting the surface water that runs into soil and slag;
Limit the erosion of slag to the off-shore sediments.
ON-SITE GROUND WATER AND SURFACE WATER
(a)
(b)
Prevent ingestion of potable (Class IIB) ground water and on-site surface water
(e.g., seeps, puddles) containing contaminants above ARARs or above risk-
based levels when ARARs are not available;
Reduce contact between contaminated soil, slag or fill and surface water and
ground water.
GROUND WATER, SURFACE WATER, AND TREATED WATER DISCHARGED TO
COMMENCEMENT BAY
(a)
(b)
Reduce discharge to Commencement Bay of contaminated waters containing
contaminants in concentrations above ARARs or risk-based goals when ARARs
are not protective or not available;
Reduce leaks and spills of contaminated surface water from drainage and
sewage systems.
6-11
-------
Although sampling of ground water has been conducted since 1987, EPA believes that the
following significant uncertainties remain regarding how contaminants move into and through the
ground water at the smelter property.
• Impacts of clean up actions on groundwater quality.
• Extent to which concentrations of contaminants in the ground water are naturally
being lowered through chemical reactions currently taking place in the ground
water.
• Extent to which dilution by seawater or ground water may also be reducing
concentrations of contaminants.
• Loadings of contaminants (for example, kilograms per day) discharged to
Commencement Bay via groundwater pathways.
EPA will continue to require monitoring of ground water to provide a better assessment of ground
water conditions, an evaluation of the effectiveness of soil and surface water clean up actions
on groundwater quality and an evaluation of the practicability of groundwater remedial measures.
6-12
-------
7.0 DESCRIPTION OF ALTERNATIVES
Asarco's Feasibility Study (FS) identified a range of alternatives to achieve the clean up
objectives and remediation goals for the smelter property and slag peninsula (Table 7-1). The
alternatives represent significantly different approaches to cleanup the Site and protect human
health and the environment. The alternatives are different, for example, in terms of their effect
on the contamination, what is necessary to maintain their effectiveness, and their cost.
The range of alternatives presents several choices for cleaning up contamination at the Site. EPA
decided among the choices in order to select the cleanup remedy for the Site.
In addition to the various cleanup alternatives identified below, demolition of the remaining
buildings and structures on the Site and use of the Ruston/North Tacoma residential soils as a
sub-base for the Site wide cap were evaluated. In addition to the cleanup alternatives selected,
long-term operation and maintenance of the cleanup activities and coordination with Site
redevelopment is necessary.
The following section summarizes the cleanup activities under each of the FS alternatives and
their estimated costs.
7.1 SUMMARY OF ALTERNATIVES
Plant Site Soils (and Slag Peninsula)
Several cleanup alternatives were evaluated in the FS for plant site soils (PSS), slag at the plant
site, and the slag peninsula.
PSS-1 is "no action." This alternative means that no further cleanup actions would be performed.
This alternative is included to serve as a baseline for the evaluation of other alternatives.
PSS-2 is "limited action" and would focus on restricting access to the Site by fences with warning
signs and deed restrictions to prohibit wells from being drilled into contaminated ground water
and future use or development on the Site. The estimated cost of this alternative (capital plus
operation and maintenance) for both PSS and the stag peninsula is $1.5 million and the estimated
time to install fencing and warning signs is one month ($1.5 million and one month).
PSS-3 includes two types of caps for the plant site and slag peninsula and three different
possibilities for excavation and disposal of soil. In general, the purposes of a cap are to prevent
the direct contact of people, animals, and surface water with contaminated soils and slag, to
prevent contaminated soil from being wind-blown, and to reduce movement of soil contaminants
through surface water into ground water. A cap can also be used to make drainage/grade
improvements and to prevent contaminated surface water from pooling on the Site.
PSS-3A A low permeability (10'7 seconds/centimeter) asphalt cap on areas of the plant site
and the slag peninsula that are not currently paved C$6.3 million and three
months).
7-1
-------
PSS-3B Soil cap over entire plant site and the slag peninsula that includes a Ruston/North
Tacoma residential soils sub-base, low-permeability clay layer, gravel drainage
layer, and clean topsoil, see Figure 7-1 C$7.6 million and five to seven years).
Excavation/Disposal:
PSS-3C Excavate soil and granular slag from the source areas (see Figure 1-1); dispose
of materials, together with demolition debris and Study Area soils, in an OCF, a
hazardous waste landfill with a low permeability liner and cap, leak detection,
collection and removal system, leachate collection and removal system and
surface run-on and run-off control systems, located in the current parking lot, see
Figure 7-2 ($23.5 million and seven years).
PSS-3D Same as PSS-3C but dispose excavated materials in an OCF located in the plant
slag area ($23.7 million and seven years).
PSS-3E Excavate, treat, and dispose source area soils and demolition debris in an off-site
hazardous waste landfill ($75 million and six months).
Estimates of Materials To Be Excavated (in cubic yards)*
Arsenic Kitchen .... 62,000.00
Cooling Pond 18,100.00
Stack Hill 54,000.00**
Copper Refinery . .. 14,050.00
Fine Ore Bin 9,850.00
Demolition Debris .. 82,000.00
SUBTOTAL 240,000.00
• Residential Soils .. 187,000.00
TOTAL 427,000.00
The Southeast Area of the Plant is not included because it is not practicable to excavate the wood debris
buried in slag that is contaminating the ground water, see Section 8 - Implementability.
This estimate includes 39,700 cubic yards from and around the car and railroad tunnels.
7-2
-------
TABLE 7-1. CLEANUP ALTERNATIVES
Plant Site Soils (PSS)
PSS-1
PSS-2
PSS-3
PSS-4
No Action (used for comparison).
Limited Action (fences and warning signs).
Capping and/or Soil Excavation:
PSS-3A
PSS-3B
PSS-3C
PSS-3D
PSS-3E
Asphalt cap over unpaved areas on Site and slag peninsula.
Soil cap over entire Site and slag peninsula.
Excavate soil from source areas and dispose in OCF in parking lot.
Excavate soil from source areas and dispose in OCF in plant slag area
• Bermed structure in parking lot.
• Three linear concrete cells with vertical walls in NE arsenic kitchen
area.
• Circular concrete tank, 525 feet in diameter in arsenic kitchen area.
• Circular bermed structure. 600 feet in diameter, in NE arsenic
kitchen area.
Excavate soil from source areas, treat and dispose in offsite landfill.
Treating Soil from Source Areas:
PSS-4A
PSS-4B
Treat soil, put back treated soil in excavated areas, dispose demolition debris in
OCF.
Treat soil, dispose treated soil in offsite landfill, dispose demolition debris in OCF.
Surface Water (SW)
SW-1
SW-2
SW-3
SW-4
No Action (used for comparison).
Monitoring Program
Cleanup Existing Surface Water Drainage System:
SW-3A
SW-3B
SW-3C
SW-3D
Repair leaks and abandon unused portions.
Abandon entire system. Construct new drainage system.
Slip line existing pipes.
Re-route surface water to alternate outfalls.
Collect and Treat Surface Water.
Shoreline Armoring
• Riprap (place rocks on shoreline).
• Artificial beach nourishment (sand and gravel).
Ground Water and Marine Sediments
• Additional monitoring and sampling.
7-3
-------
Clean Soil (1 ft. Deep)
Clay (1 ft. Deep):
'•:••:.:{ Ruston/North
Residential Study Area Soil
Slag or Soil
• Groundwater:
Surface
After
Demolition
FIGURE 7-1: EXAMPLE OF MULTI-LAYER SOIL CAP
7-4
-------
IS
o
12
CO
K
3
••••••
vrrass * •
: Cover Soil (2 ft. Deep) .
\\\\\\\\ \Fflter Material \\\\\\\\
•> Ss/) Drainage Material (1 ft. Deep) &>
' vjU-' \ — ' V / ^ \ J U» \_J U- \ 1 \*~ \_J ^- \ -^ \ j x>
// // // // // // Fabric ^f***T'/-//' // // /-^ •^r/ //
-_-^-_Compacted__Soilj2_ ft. _Deep)-_-__-_
•'_•>-.' --•• -i .'* ,'4.- •• ? ' /V'V ••:'- '
^ '* ' •-..,'•
/ .':•«•,• Waste Material - *" - ' «
* . . • 4 • ' ' ' .'.'•'"'
•• . -.'- •** • • *' '. / ' . ...4 •' , ^" & . -. * ' '•
•« • -^4 ' . ' . * . • . • « - " _.- •; .' • " .
« A •-••-' • • •' - ' « ••
\\\\\\\\ Filter Material \\\\\\\X
o'$&$& yy***&* Material^(5^f3 ^t
// // //^ // // x^/«ibric '-"^er // // // // // //
_-_-_— _Compacted Soil (l ft. Deep)- _~_~ _
^^/^Drainaffe Material (1^ ft. Deep)>o Qf
// // // // // //Fabric toner // // // // // //
_~_T~_~_ Compacted Soil (3 ft. Deep )_—_—_
••.•.•.•••.••••••••.•.•:•.•.•.••.•.•.•. Nfltivp Soil.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-/.-.-.-.
^ *— •
~r
i
v
\
V
Plastic
Liner
Drainage
Pipe
Plastic
liner
Drainage
Pipe
Plastic
Liner
FIGURE 7-2: HAZARDOUS WASTE ON-SITE
CONTAINMENT FACILITY (OCF)
7-5
-------
Additional On-Site Disposal Alternatives:
After completion of the FS, Asarco submitted further alternatives for constructing an OCF with
a capacity of 240,000 cubic yards as follows:
• Bermed structure in the parking lot built into the hillside and bermed on three
sides (estimated cost is $18 million), or
• Three concrete cells in a row with vertical walls located northeast of the arsenic
kitchen area. The approximate size of each cell is 200 by 1200 by 45 feet high
($32 million), or
• Circular concrete tank, about 525 feet in diameter, located northeast of the arsenic
kitchen area ($22 million), or
• Circular bermed structure, about 600 feet in diameter, located northeast of the
arsenic kitchen area ($22 million).
Soil Treatment:
The two PSS-4 alternatives involve treatment of contaminated soils at the plant site using
chemical fixation and disposing of them in different locations. Chemical fixation means mixing
excavated contaminated materials with cement and lime in order to reduce the mobility of the
contaminants.
PSS-4A Put back treated soils in excavated areas on-site and cover the area with a cap.
Demolition debris would be disposed in an OCF ($48.2 million and six months).
PSS-4B Dispose of treated soils in an off-site landfill and demolition debris in an OCF
($86.4 million and six months).
Surface Water
Several cleanup alternatives were evaluated to address contaminated surface water at the Site.
SW-1 is no action.
SW-2 relies on soil removal and groundwater remediation to reduce the release of contaminants
(for example, arsenic) to surface water. A surface water monitoring program would evaluate the
effectiveness of this approach. The estimated cost of the monitoring program is $943,000 and
the estimated duration is ongoing.
SW-3 consists of four different measures with respect to the existing surface water drainage
system:
SW-3A Repair leaks in the existing system; ongoing maintenance to prevent leaks in the
future; plug and abandon portions of the existing system not used ($737,000 and
three months).
7-6
-------
SW-3B Plug and abandon the entire existing system. Construct new drainage system,
including pipes, inlets, and manholes, that prevents leaks and resists corrosion
($1.6 million and 3 months).
SW-3C Insert smaller PVC pipe (or slip lines) into existing pipelines; seal existing drains
and sumps and manholes; replace open ditches with new pipes ($969,000 and
three months).
SW-3D Re-route surface water that runs onto the Site to alternate drain outfalls ($439,000
and two months).
SW-4 would collect and treat contaminated surface water in a water treatment plant located on
the plant site ($23.6 million and ongoing).
Shoreline Armoring
The most effective measure to prevent erosion of the slag shoreline into Commencement Bay is
called shoreline armoring.
There are two main types of armoring:
• Line the shore along the smelter property and the slag peninsula with riprap (large
rocks) underlain with 2 feet of smaller rock, see Figure 7-3. Riprap would not be
installed on the interior portion of the slag peninsula because of the minimal slag
erosion which occurs there ($6.2 million and from six to twelve months).
• Use artificial beach nourishment, which consists of depositing sand and gravel to
form a pebble beach. Sand and gravel that erodes would need to be replaced on
an annual basis ($1.4 million and two months for beach nourishment).
Mitigation for damage caused to natural resources (e.g., intertidal habitat) would be required for
either of these options. The full extent and design of armoring is presently unknown, so the cost
to complete mitigation (e.g., replacement of damaged resources) is not estimated. The time to
complete mitigation could be up to 2 years, which could be done concurrently with or
immediately after shoreline armoring.
7.2 SIGNIFICANT PUBLIC COMMENTS AND ADDITIONAL ANALYSES
EPA received many comments on its Proposed Plan for cleaning up the site. These comments
are responded to in the Responsiveness Summary (Appendix A). In this section, EPA
summarizes some of the most significant technical comments and describes the additional
analyses that EPA conducted in response to such comments.
7.2.1 On-Srte Containment Facility Comments
Several commenters recommended that if the OCF were selected, it should be comprised of
multiple cells holding different concentrations of contaminated soil. The reasons given for an
OCF with multiple cells were that it would provide one more level of protection against leaking,
provide more precise monitoring capabilities, and be easier to remove soil in the future should
an innovative treatment technology become available.
7-7
-------
c
JO
"5
JB
0)
O
O
2 t O.
> o
O o> C
w g> o
Cxi O 'C
v! ^ o
»- O JI
O
E
o
2
a:
<
UJ
a:
o
x
o
UJ
a.
x
UJ
UJ
a:
z>
O
-------
Although there may be situations where multiple cells are appropriate for hazardous waste
landfills, EPA does not agree that multiple ceils are warranted for the OCF for this Site for several
reasons.5 First, the contaminated soil and debris that will be disposed is contaminated only with
metals rather than a mixture of metals and organic contaminants. Therefore, even though a wide
range of metal concentrations found is in soil, adverse reactions caused by different types of
contaminants mixing together within the OCF are not likely to occur. Another reason adverse
reactions are not expected is that contaminants leaching out of the soil are expected to decrease
once the OCF is closed (i.e., when the contaminated soil and debris is isolated from surface and
ground water).
EPA does not agree that multiple cells would allow for more precise monitoring of down-gradient
ground water. The reason is that wastes with the same contaminants would be disposed in each
of the cells so in the event that leachate move through the OCF liners and reaches the ground
water it would be difficult to identify from which cell it came.
Operation and maintenance of several leachate collection and removal systems due to multiple
cells would be more difficult than operating a single cell leachate collection and removal system.
EPA does not believe that operating multiple leachate systems would significantly increase the
effectiveness of the OCF. Finally, there do not appear to be any new promising treatment
technologies on the horizon that would justify disposing soils with different levels of
contamination in separate cells.
7.2.2 Soil Treatment Comments
Other commenters recommended that contaminated soil should be treated prior to disposing it
in the OCF. The basis for this recommendation was to provide more protection should part of
the OCF fail in the future and to be consistent with land disposal restrictions (UDR), which require
treatment prior to disposal.
In response, EPA performed an analysis to determine whether treating soils prior to disposal in
an OCF is necessary. EPA compared the potential for contaminants leaching from an OCF into
underlying ground water if soils were not treated versus if some (15 percent) of the soils were
treated. EPA used 15 percent to represent the percentage of soils that are most highly
contaminated.
First, EPA assumed that the OCF had a "good" liner and a "good" cap, meaning that the liner and
cap conformed to landfill performance requirements. EPA compared estimated leachate rates
from this OCF if soils were not treated versus if 15 percent of soils were treated. In both cases,
the predicted contaminant loading to ground water was minimal. Treatment did not provide a
significant advantage in effectiveness.
Second, EPA assumed that the OCF had a "poor" cap and no liner. Again, EPA compared
estimated leachate rates for no treatment versus 15 percent treatment. The predicted rate for no
treatment was 106 grams of arsenic per day and the predicted rate for 15 percent treatment was
5 The reasons that landfills are normally separated into multiple cells is to (1) separate incompatible wastes and
the leachate from those wastes and (2) to limit the open portion of a large landfill that will operate over many years so
as to limit the area available for collection of precipitation. Under this scenario, each cell would be constructed and
covered prior to constructing another cell. Neither of these reasons are relevant to the Asarco OCF as the waste to
be placed is not incompatible and the time the OCF will be open is short.
7-9
-------
93 grams of arsenic per day. EPA concluded that this difference is not significant and that'
treatment did not provide an advantage in effectiveness (but the analysis does show that
maintenance of the OCF's cap and liners is important). See Appendix D.
Based on this analysis, EPA believes that treating soils prior to disposal in a properly maintained
OCF is not necessary.
In response to the LDR comment, EPA's policy is that waste that is consolidated within an area
of contamination is not "placement" and therefore does not require compliance with LDRs (i.e.,
treatment prior to disposal).
After the Proposed Plan was issued, Asarco submitted its final treatability analysis. One
conclusion was that treating soils results in a 30 to 60 percent increase in the volume of soil.
The analysis also reported results of additional TCLP and water leaching tests conducted on the
treated soil. The TCLP data taken 28 days after treatment, although well below regulatory levels,
is slightly higher than data taken immediately after treatment. It is not certain whether this
indicates that treatment would be less effective over time in immobilizing contaminants. However,
favorable results were obtained from water leaching tests, another measure of the effectiveness
of stabilization/solidification. Asarco's analysis is in the administrative record.
7.2.3 Shoreline Armoring Comments
Several commenters questioned whether the slag shoreline was eroding, whether the eroded slag
particles caused an adverse impact on the adjacent marine environment, and why the shoreline
needed to be armored as it is already providing a suitable habitat for marine biota. If shoreline
armoring was determined to be necessary, commenters also questioned how it would be
anchored to the existing slag face and why riprap (large rocks) was selected instead of artificial
beach nourishment (small rocks and sand) to armor the slag.
The need for shoreline armoring is based on the visual observation that slag is eroding in several
locations along shoreline and on a report published by Battelle (Crecelius 1986) that showed that
metals released from freshly exposed slag are toxic to marine organisms for up to three to four
months. After evaluating the comments received, EPA still believes that some amount of
shoreline armoring will be necessary. However, EPA has determined that before the design of
the shoreline armoring begins additional data should be collected to determine (1) the extent of
shoreline erosion; (2) how and where armoring should be placed; and (3) the impact of armoring
to the existing marine biota versus the impact of not armoring slag to the marine biota over time.
After reviewing the most recent literature and discussing riprap versus artificial beach nourishment
with the Corps of Engineers, EPA believes that the marine environment off-shore of the Asarco
Site would not support artificial beach nourishment due to the high wave energy and fast currents
in the area (See memo by ROY F. WESTON, Inc. in the Administrative Record, Section 2.4.1).
7-10
-------
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
EPA uses nine criteria to identify its preferred alternative for a given site or contaminant. With
the exception of the no action alternative, all alternatives must meet the first two "threshold"
criteria. EPA uses the next five criteria as "balancing" criteria for comparing alternatives and
selecting a preferred alternative. After public comment, EPA may alter its preference on the basis
of the last two "modifying" criteria.
This section evaluates both the alternatives developed by Asarco (described in Section 7.0) and
the remedy selected by EPA (described in Section 9.0) based on the nine criteria described in
Table 8-1. The purpose of this evaluation is to highlight the most significant advantages and
disadvantages of the alternatives in relation to each of the nine criteria (a more detailed
evaluation is provided in Table 5-4-1 of Asarco's FS).
All nine criteria are important; tout they are weighed differently in the decision-making process
depending on whether they describe a required level of performance (threshold criteria), provide
for consideration of technical or socioeconomic merits (balancing criteria), or involve the
evaluation of non-EPA reviewers that may influence an EPA decision (modifying criteria). The
modifying criteria are generally considered in altering an otherwise viable alternative.
The no-action and limited action alternatives, discussed in Section 7.0, are not protective of
human health and the environment and thus are not further evaluated under the nine criteria.
Neither alternative effectively addresses contaminants moving into the ground water even though
human health may be somewhat protected through administrative or legal measures identified
under "limited actions."
(1) Overall Protection Of Human Health And The Environment
The key factor in evaluating the overall protection provided by each of the alternatives is the
extent to which an individual's exposure to contaminated soil, slag or surface water is reduced
or eliminated and the extent to which the contaminants moving into surface water and ground
water are reduced or eliminated.
Plant Site Soils. Asphalt and multi-layer soil caps are protective because they reduce direct
contact with contaminated soils and prevent wind-borne releases. Caps also reduce the
migration of contaminants from soil to surface water or ground water by reducing surface water
flowing through the soil. The more impermeable a cap is, the less surface water will penetrate
the cap.
8-1
-------
TABLE 8-1. ERA'S NINE EVALUATION CRITERIA
THRESHOLD CRITERIA
1. Overall protection of human health and the environment - How well does the
alternative protect human health and the environment, both during and after
construction?
2. Compliance with federal and state environmental standards - Does the
alternative meet all ARARs and state and federal laws?
Alternatives that are not protective or do not attain ARARs are not evaluated further under
the remaining criteria.
BALANCING CRITERIA ^
3. Long-term effectiveness and permanence - How well does the alternative protect
human health and the environment after completion of cleanup? What, if any, risks
will remain at the site?
4. Reduction of toxicity, mobility, or volume through treatment - Does the
alternative effectively treat the contamination to significantly reduce the toxicity,
mobility, and volume of the hazardous substance?
5. Short-term effectiveness - Are there potential adverse effects to either human
health or the environment during construction or implementation of the alternative?
How fast does the alternative reach the cleanup goals?
6. Implementability - Is the alternative both technically and administratively feasible?
Has the technology been used successfully on other similar sites?
7. Cost - What are the estimated costs of the alternative?
MODIFYING CRITERIA
8. State acceptance - What are the state's comments or concerns about the
alternatives considered and about EPA's preferred alternative? Does the state
support or oppose the preferred alternative?
9. Community acceptance - What are the community's comments or concerns about
the preferred alternative? Does the community generally support or oppose the
preferred alternative?
8-2
-------
Soil excavation in source areas would significantly reduce migration of contaminants to ground
water and would, therefore, be protective of off-shore sediments and sea life. Disposal of soils
in an appropriate disposal facility, either on site or off site, would prevent direct contact to
humans or animals and prevent releases to the environment in the future. Off-site disposal would
be protective of ground water and nearby populations because it would permanently remove
contaminated source area soils off the Site. An on-site disposal facility (OCF) in the parking lot
area, on the plant slag, or in the arsenic kitchen area can be designed with the appropriate
engineering measures and institutional controls to minimize or eliminate direct contact with the
contaminated soils disposed in it. These measures will also reduce the potential for releases to
the environment from the OCF. The OCF is a permanent disposal facility for soils and debris.
Treatment of soils would also significantly reduce the potential for the release of chemicals into
the environment.
Using the residential soils as a sub-base for a cap is protective because the soils would be
placed under a low permeability clay layer and soil cap. The appropriate institutional controls
would prevent disturbances of the cap. These soils have not been found to leach above
regulatory levels.
In addition, these soils will be disposed on top of the non-source area soils and slag that are not
located near ground water. Residential soils contain significantly lower concentrations of
contaminants than the material they will be placed on. Therefore, disposing residential soils on
site will not add to existing groundwater contamination.
Demolition. The conventional demolition techniques for dismantling buildings, the only
alternative evaluated, will be performed in a manner that is protective by first cleaning the
buildings and then using dust suppression measures during the demolition activities. Any water
generated during the dust suppression activities will be collected to the maximum extent
practicable to prevent release into the environment. The effectiveness of dust suppression
activities will be evaluated with ambient air monitoring.
Surface Water. For surface water, the replacement of the existing drainage system is protective
of the environment because contact between surface water and contaminated sediments in the
pipes would be eliminated. Releases of contaminated surface water to ground water through
leaks in the pipes would also be eliminated. Slip-lining or repairing the existing drainage system
may achieve these benefits, however, the location of all of the existing pipes is not known and
many of the existing pipes may not be large enough to be slip-lined. These reductions would
result in lower discharges of contaminants to Commencement Bay. The diversion of surface
water run-on away from contaminated soil would also control contact between surface water and
contaminated soil.
Implementation of erosion controls and other best management practices during the cleanup
would control contact between surface water and newly exposed contaminated soil and reduce
the transport of contaminants to Commencement Bay. Treatment of surface water would
permanently reduce contaminants currently discharged through outfalls to Commencement Bay,
but unless the source(s) of contamination is removed, treatment time would be indefinite.
Ground Water. Although specific active groundwater cleanup activities (e.g., pump and treat)
will not be conducted during this phase of cleanup, the contaminant loading to the ground water,
and to Commencement Bay is expected to decrease significantly based on soil removal, capping
of the soil and slag and replacing the surface water drainage system. The potential for exposure
8-3
-------
to humans will be significantly decreased by placing deed restrictions on the property to prevent
the use of ground water.
Shoreline Armoring. Both shoreline armoring and artificial beach nourishment are protective
because they control the erosion of the slag shoreline into Commencement Bay and will reduce
contaminant leaching from freshly exposed slag faces.
All actions are protective except the no-action, monitoring, or limited action alternatives.
(2) Compliance With Federal And State Environmental Standards
ARARs for all of the alternatives are identified in Table B-8 in Appendix B of this ROD. The
following discussion highlights the more important ARARs for this cleanup.
All alternatives will comply with ARARs except the monitoring or limited action alternatives.
Plant Site Soils And Debris. For soil, an important requirement is attaining the soil cleanup
levels and complying with the requirements for selecting cleanup actions under the state's Model
Toxics Control Act (MTCA).
Residential standards for soil cleanup will be attained through removal of soil from the source
areas and capping the Site (see Figure 7-1 for diagram of soil cap). Institutional controls would
ensure that the integrity of the cap is maintained. Construction and maintenance of a cap would
allow for a variety of potential uses, including residential, recreational, and commercial uses.6
MTCA's requirement for selection of cleanup actions is discussed in Section 10.4 ("Utilization of
Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent
Practicable").
Requirements for design, construction, and operation and maintenance of an OCF are set forth
in federal and state law (see Section 9.9, performance standards for the OCF). Federal and state
laws for hazardous/dangerous waste landfills include requirements for groundwater monitoring,
closure and post-closure, and landfill design and construction.
Both EPA and the State of Washington have "Area of Contamination" policies that provide
flexibility when consolidating hazardous or dangerous waste within the portion(s) of the Site that
contain already-existing continuous contamination. For example, consolidation of soil and debris
on site will not trigger requirements for treatment in order to comply with LDR.7
Under the Clean Water Act, mitigation measures must be conducted if capping or other cleanup
measures will result in adverse impacts to wetlands or other natural resources.
6 A cap may not be necessary in some areas of the Site if the contaminant levels remaining in soil after excavation
are below the action levels for the Ruston/North Tacoma residential cleanup (230 ppm arsenic, 500 ppm lead) or
comparable levels for other contaminants as determined by EPA and Ecology. In such event, soil removal would be
combined with adoption of appropriate components of the community protection measures program being used in
Ruston/North Tacoma
7 The Proposed Plan referenced the Corrective Action Management Unit (CAMU) rule. Because treatment has not
been selected for the cleanup, the CAMU rule is not an ARAR.
8-4
-------
Demolition. The buildings remaining on site will be demolished as pan of this cleanup.
Requirements that were used during the previous demolition phase will be applicable to the
remaining demolition (see EPA's ROD dated December 31,1990). These requirements include
testing of debris to determine whether it is a hazardous or dangerous waste and, if so, handling,
storage, and disposal of such waste in accordance with federal and state standards. Temporary
on-site storage of hazardous waste (e.g., materials removed from the fine ore bins building or
source area soils that are excavated while the OCF is under construction) will comply with
requirements for waste piles.
Surface Water. Best management practices (BMP) will be used during soil excavation to reduce
contact between surface water and newly exposed contaminated soils. Examples of BMPs
include sediment ponds, silt fences, diversion ditches, and cut and fill slopes.
The objective of surface water cleanup is to attain requirements for stormwater discharges and
surface water cleanup standards under MTCA (see Section 9.9 for surface water performance
standards). It may be necessary to establish a mixing zone to attain the discharge limitations for
surface water from the point source discharges at the Site (the three surface water outfalls). A
mixing zone measures compliance at a location in the surface water near, rather than at, the
point of discharge and is authorized under WAC 173-201A-100. Whether a mixing zone is
appropriate and, if so, the parameters of a mixing zone, will be determined during remedial
design.
Ground Water. EPA will implement a two-step approach with respect to restoring ground water.
The first step is removing the contaminated soils that are the sources of contamination in ground
water and continued monitoring to determine the impacts of source control on groundwater
quality. The second step would include further active measures to cleanup ground water, if
necessary and as feasible, to attain the required groundwater cleanup levels under MTCA.
The source control measures in the first step are in effect an interim action with respect to
ground water. Because it is not certain that source control measures alone will restore
groundwater quality to required levels under MTCA, EPA is using the interim measures waiver
for groundwater ARARs. This means that attainment of the ground-water cleanup levels is
deferred until the effectiveness of source control can be evaluated. EPA's preliminary
remediation goals for ground water (see Section 9.9) will be used as benchmarks for this
evaluation.
In the interim, EPA will require Asarco to implement institutional controls (deed restrictions) to
ensure that ground water at the Site is not used for drinking water.
Shoreline Armoring. Under the Clean Water Act, mitigation measures must be conducted if
armoring will result in adverse impacts to intertidal habitat.
(3) Long-Term Effectiveness And Permanence
Plant Site Soils. The alternatives that excavate contaminated soils in source areas would be
more effective over the long-term in restoring ground water and surface water quality and
preventing direct contact and ingestion than alternatives that leave such soils in place, even if
capped. Permanently removing the primary sources of contamination is a key factor in cleaning
up ground water and surface water.
8-5
-------
The most widely discussed issue for this cleanup has been how to dispose the contaminated soil
that is excavated from the source areas. The alternatives range from disposing the soils in an
OCF, treating the soils by solidifying them using a cement and lime matrix and using the treated
soil as sub-base for a site cap, treating such soils and disposing them in an on-site solid waste
landfill, or transporting the soils to be disposed in an off-site hazardous waste landfill.
The following paragraphs discuss the effectiveness of each of these alternatives over time.
Plant Site Soils - Treatment An effective treatment method for the metal-contaminated soils at
the Asarco smelter is solidification/stabilization. This method does not destroy or detoxify the
contaminants in the soil but rather binds the contaminated soil with lime and cement to create
a concrete matrix. The contaminants are less able to migrate through the soils into other media,
for example, ground water, surface water, or air.
Asarco has performed pilot tests on nearly 500 cubic yards of contaminated soil from source
areas at the smelter. The results, some of which were received after the Proposed Plan was
issued (see Appendix C for a summary of the report), generally show that treatment will effectively
bind the contaminants for a long time. The potential for contaminants to migrate into the ground
water or surface water if the treated soil comes into contact with water is expected to be minimal,
if the concrete matrix remains stable.
This method of treatment, however, has been used on contaminated soils at other sites only in
the last several years. Therefore, it has not yet been proven that actual results of solidification
over many years will match the predicted results from pilot tests. Also, TCLP leaching results
taken 28 days after soil treatment show a slight increase compared to TCLP results taken
immediately after treatment. Although both sets of results are below hazardous waste levels, it
is not certain whether this is indicative of a long-term trend towards increased leaching.
In addition, there are other long-term concerns with selecting treatment at this Site. Many of
these concerns relate to the compatibility of cleanup with future uses of the Site. It should be
noted that Asarco's land use plans were based on an OCF. Disposing treated soil on site is not
necessarily compatible with these plans for the reasons noted below. These "disadvantages"
compared to disposal in an OCF arise because land use plans based on treatment were not
developed. Current land use proposals do not discuss whether the development "disadvantages"
of disposing treated soils on site can be made compatible with land use plans.
The primary concern is that mixing in the treatment additives increases the volume of the
contaminated soil approximately 30 to 60 percent. It is not certain that treated soil can be
compacted to significantly reduce the increased volume. Because it is important that the
concrete matrix remain relatively undisturbed and because the treated soil may not be stable
enough to support buildings above it, disposing of an increased volume of material on site may
impact plans for future construction on the property. Treated soil would have to be disposed
only in areas where no construction is likely to occur.
It would also be necessary to monitor the Site to verify the continued effectiveness of treatment.
Because sampling treated soil through a site cap is not recommended (punching holes through
a low permeability cap is not a good practice), EPA most likely would require continued
monitoring of ground water to detect whether concentrations of contaminants in ground water
are increasing as a result of metals leaching out of the treated soil. If treated soil is widely
dispersed on-site and problems in ground water are detected, it may be difficult to determine
8-6
-------
which specific areas of treated soil are responsible, thus making it harder to correct the problem.
Disposal of treated soil in a solid waste landfill would eliminate many of the problems associated
with future Site development and monitoring of the treated soils beneath a Site cap.
Another concern is that the effectiveness of treatment was not demonstrated on oversize material
(greater than 2 inches in diameter) such as gravel, cobbles, bricks, wood, concrete and other
masonry and building debris. Whether a modified process, which could include crushing the
oversize material into smaller pieces, would be effective is not known. Accordingly, it is possible
that even if treatment was selected, there may still be a significant volume of oversize materials
from the Asarco Site that would need to be disposed in another manner.
The last concern is that because concentrations of contaminants are not reduced, it would still
be necessary to cover the treated soil with a cap. The cap would need to be inspected and
maintained 'on a regular basis in order to ensure that people do not come into contact with the
treated soil in the future. Earthquakes or landslides that affect the cap would need to be
responded to in order to prevent contact with the treated soil. It should be noted, however, that
because contaminated soil and slag outside the source areas will remain at the Site, a cap over
the entire Site will be necessary, and will require inspections, regardless of whether treatment is
used.
Plant Site Soils»Disposal in an OCF. This option calls for disposal of contaminated soil and
debris in a landfill that would be constructed on site known as the OCF. The design,
construction and operation of the OCF would conform to requirements for hazardous waste
landfills. Three important issues are discussed in this section regarding an OCF: what type of
structure will be built, how that structure will be maintained, and where it will be located on the
Site.
The purpose of the OCF is to isolate the contaminated source area soils and debris in a confined
area so that contaminants do not migrate into the environment. The OCF will be composed of
multiple layers of clean soil and clay that are several feet thick with synthetic liners above, below
and around the contaminated soil. These multiple layers serve two primary purposes: to prevent
rainwater and ground water from moving into the OCF (water coming into contact with
contaminated soil and debris increases the movement of contaminants) and to collect, remove
and dispose of any liquids from inside the OCF. As long as these multiple layers are designed,
constructed and maintained properly, the OCF will be effective over the long-term in isolating the
contaminated materials. Proper design and construction of the OCF will include safeguards to
prevent or minimize damages resulting from earthquakes or landslides to the maximum extent
practicable.
In addition to the multiple layers of the OCF acting as a barrier to groundwater infiltration, a
groundwater diversion system will be constructed in order to re-route ground water away from
the OCF.
The primary disadvantage of the OCF option is that the soil and debris will not be treated and
will continue to contain high concentrations of contaminants. If there is a breach of the OCF
structure, the soil and debris could pose a threat to human health and the environment. Two
examples of structural concerns are the finite life of the synthetic liners that will be part of the
OCF structure and the potential for the cover to fail. See Section 7.2 above for discussion of
EPA's analysis of whether to treat soils prior to disposal in an OCF.
8-7
-------
In order to address these concerns, a consistent and reliable operation and maintenance (O&M)
program is necessary to ensure the continued effectiveness of an OCF. Important components
of the O&M program would include a leak detection system and collection and removal of
leachate. The clay portion of the liner should have an indefinite life. One objective in designing
the OCF will be to provide as much access as practicable to the walls and cover of the OCF for
maintenance and repair.
Maintaining the effectiveness of the cover is also important. Water and wind erosion, lack of
vegetation, excessive sunlight, and disturbance by animals or people are all potential problems
for landfill covers. Methods to address these potential problems include burying the cover below
many feet of soil, ensuring that surface water drains properly over the top of the structure,
diverting ground water away from the structure, and maintaining healthy vegetation over the cap
to minimize soil erosion.
A program to monitor ground water downgradient from an OCF would be required to ensure that
contaminants are not moving out of the structure and into the environment. One potential
advantage of the OCF over treatment is that, because the wastes will be confined to a specific
area of the Site, it would be easier to monitor downgradient ground water and perhaps to identify
and correct problems.
Different kinds of designs for an OCF or landfill were evaluated in the FS, such as linear/concrete
cells, circular tanks, and circular bermed structures. The circular earth berm is most like a
conventional landfill and it can more readily comply with the requirements for hazardous or solid
waste landfills than the linear or concrete tank alternatives.
The vertical walls that are part of the linear, concrete cells would be more difficult to design and
construct to meet containment requirements. Another disadvantage is that it would be more
difficult to divert ground water below and around a linear system than it would be for the circular
systems.
Another important issue with respect to long-term effectiveness for an OCF is its location at the
Site. All of the proposed locations for an OCF would be protective of the local community and
the surrounding environment. The parking lot is the closest location at the Site to existing
residences. The arsenic kitchen and plant slag areas are considerably further removed from
residential areas. The depth to ground water in the parking lot ranges from 40 to 90 feet,
compared to approximately 5 feet in the arsenic kitchen and approximately 10 feet in the slag fill.
The arsenic kitchen area was selected as the location of the OCF because that location is most
compatible with future land use plans. Because ground water is relatively shallow in the arsenic
kitchen area, however, an OCF in this location would have to be well-engineered and maintained
in order to be protective of ground water. "Well-engineered and maintained" refers to the liners,
leachate collection and removal systems, cover, diversion system, and other components
described above. For example, well-maintained impermeable and drainage layers would need
to be part of the bottom liner in order to be protective of ground water.8
8 The bottom liner will be a double liner system. The first liner collects leachate (water that passes through the
waste and is contaminated). The leachate is pumped from a trench and treated and/or removed. The second liner is
below the first and collects any leachate that may have passed through the first liner.
8-8
-------
Plant Site Soils - Off-Site Disposal Options. Another disposal alternative is transport and
disposal of soil and debris in an off-site hazardous waste landfill. This would eliminate the
problems described above associated with managing such waste on site. It should be
recognized that slag and contaminated soil in non-source areas would remain on-site and still
would have to be addressed by capping.
Plant Site Soils - Capping. The above paragraphs discussed management of soils that are
significant sources of contamination to ground water. Soil and slag in other areas are believed
to have a lower potential for contaminants to migrate into ground water, however, these areas
still have elevated levels of chemicals for which a cleanup action is necessary. Leaving such
soils in place and placing a multi-layer soil cap on top of them to reduce surface water infiltration
will be the most effective in protecting surface water and ground water over the long-term.
Further, the soil cap will reduce leaching in the Southeast Plant area which is impracticable to
excavate (see Section 8.6 below).
Either a soil or asphalt cap would be effective in: eliminating the risk of direct contact with or
ingestion of contaminated soils and slag; preventing erosion of contaminated soil or fine grain
particles of slag into Commencement Bay; reducing the extent to which surface water comes into
contact with contaminants in soil and transports them directly or via ground water to
Commencement Bay; and preventing the pooling of contaminated water on site. In order for
either type of cap to be effective over the long-term, inspections, maintenance, and restrictions
on digging below the cap would be necessary. An asphalt cap will require more inspections and
maintenance than a soil cap to prevent, detect, and repair cracks and other defects.
An effective long-term solution for disposal of soil from the Ruston/North Tacoma residential
cleanup is to use such soil as sub base for the smelter site cap on top of slag. The site cap
would prevent direct contact with the residential soil and reduce surface water coming into
contact with the soil. A soil sub-base still would be required on the Site even if Ruston/North
Tacoma residential soils were not used.
Demolition. Several buildings remain on site, such as the fine ore bins building, which is used
for storage of contaminated materials, the administration building, the surface water evaporation
system, and the transformer buildings. The demolition of remaining structures and disposal of
the debris will remove the potential for contact with contamination in the buildings and
structures. Disposal of materials stored in the fine ore bins building in the OCF (hazardous waste
demolition debris, contaminated ERA soils, and calcine deposits) will eliminate the threat that
contamination from the demolition debris and the calcine deposits will migrate into the
environment. Materials in the fine ore bins building are suspected of contributing to groundwater
contamination.
Surface Water. For cleanup of surface water, plugging and abandoning the existing drainage
system and replacing it with a new surface water drainage system is the most effective approach
over the long term. This alternative will eliminate releases of soil and water from the existing
system into ground water and eliminate contact between surface water and contaminated
sediments in the pipes.
It would be less effective to attempt to repair leaks and to clean out contaminated sediments
because the location of all existing pipes is not certain. Inserting slip lines into pipes with cracks
would also be somewhat effective but could not be done in all pipes due to the small diameter
8-9
-------
and deteriorating condition of some of the existing pipes. Some pipes may need to be replaced
even if sliplining were selected as the remedy.
Rerouting surface water that runs onto the Site, from Ruston for example, would reduce contact
with contaminated Site soil but would not affect surface water on the Site itself, i.e., rainfall. A
new or repaired on-site drainage system would still be necessary.
EPA evaluated treating surface water before it discharges into Commencement Bay even before
contaminated soil from the source areas is excavated. Removing the source areas is a
necessary first step in any cleanup scenario. Unless the source areas are removed, treatment
of surface water could be required indefinitely. Although treatment of contaminated surface water
is potentially effective, it may be difficult to consistently achieve cleanup levels given the volumes
of water requiring treatment, estimated to be up to 900 gallons per minute. Also, treatment of
all surface water may not be possible during significant rainfalls. Bypass flow could be necessary
during such events.
Because the cleanup includes source removal, a new drainage system, and a site cap, it is likely
that remaining contaminated surface water, if any, would be from off-site areas. One objective
of the new drainage system would be to avoid recontamination of the site cap by surface water
run-on. Also, if surface water run-on from off-site areas is contaminated, this problem may need
to be addressed in the future.
Ground Water. It is anticipated that groundwater contamination will decrease over the long term
because the most significant sources of the contamination will be removed and the entire site
will be capped. One purpose of the site cap is to reduce surface water flow into the remaining
on-stte contaminated soils, which should further reduce the movement of contaminants from soil
into ground water.
Shoreline Armoring. The use of large rocks or boulders to armor the shoreline has a better
potential to withstand current and wave action and remain in place compared to using the
smaller pebbles described in the artificial beach nourishment alternative. If artificial beach
nourishment were used, it would be necessary to include measures such as stone face dikes or
breakwaters to decrease the effects of the currents and wave energy to prevent extensive erosion
of small rocks and sand. If small rocks and sand had to be replaced frequently, recolonization
of marine life would be difficult.
In addition, neither riprap nor beach nourishment are typically placed on slopes as steep as
those found at this Site; a cutback would be required for either alternative. Areas that are
steeper than 1 (horizontal) to 1.5 (vertical) will need a cut back. The toe of the riprap would need
to be constructed 1.5 to 2 times the wave height below the water line. Established construction
techniques would be used to anchor the toe and face of the armoring. Although stone faced
dikes, breakwaters and revetments are commonly constructed, it is uncertain whether it will be
possible to place these types of structures at the Asarco Site.
(4) Reduction Of Toxicitv. Mobility. Or Volume Through Treatment
Plant Site Soils and Surface Water. Soil treatment by solidification/stabilization of source area
soils ranks the highest for this criterion. The mobility of contaminants in the soil would be
significantly decreased by binding them up in a cement matrix. However, the toxicity of the
8-10
-------
contaminants would not be decreased and the volume of soil would increase by approximately
30-60 percent. Soil excavation and disposal in an OCF does not satisfy this requirement.
Treatment of surface water is the only surface water alternative that would reduce the mobility,
toxicity, and volume of contaminants. Disposal of contaminated sludges from the surface water
treatment process would be necessary.
(5) Short-Term Effectiveness
Plant Site Soils. All alternatives involving soil excavation would result in dust emissions, surface
soil erosion, noise and truck traffic. Air monitoring, dust control measures (for example, wetting
the soil prior to excavation) and using established transportation routes would be required to
mitigate these effects. Also best management practices would be used to control surface water
coming into contact with newly exposed contaminated soil. Other traffic control measures could
be implemented, such as cleaning truck wheels and lining and covering truck beds when
transporting contaminated materials on public roads.
Health and safety procedures would be required under all of the alternatives for workers involved
with the handling of contaminated soil.
The construction of any of the alternatives for landfills would result in the short-term release of
dust, increased impact of trucks and excavation equipment on site and on public roadways
surrounding the site. Safety and dust controls measures would be implemented.
The primary potential short-term risk of off-site disposal is from the large number of trucks hauling
material off the site. All transportation and safety requirements would be required.
Capping the soil in place with an asphalt or soil cap would pose limited short-term risks from
heavy equipment movement and dust generated from grading the Site. Asphalt capping would
take approximately 3 months if Ruston/North Tacoma residential soils are not used as sub-base.
If all of the Ruston/North Tacoma residential soils are used as a sub-base, soil capping would
take approximately 7 to 8 years. If all residential soils are not disposed on the site, soil capping
and regrading could be completed within 12 months. Residential soil that is excavated after the
cap is in place would be disposed in an appropriate off-site facility pursuant to EPA's ROD and
Ecology's Dangerous Waste exemption for Ruston/North Tacoma.
The stabilization treatment system would be fully enclosed thus preventing releases of
contaminants into the air and would, therefore, cause the least short-term risk. The system used
during the pilot-scale study effectively controlled releases and similar measures are feasible for
a full-scale project.
Demolition. The alternatives for demolishing and dismantling buildings will be effective in safely
removing the existing structures. However, short-term releases of dust and particulates will result
from these activities and will need to be effectively controlled. Demolition will include dust
suppression measures to minimize dust emissions to ambient air and to protect workers. Air
monitoring devices will also be used to determine whether air emissions exceed the standards
used during previous demolition activities; if so, demolition activities will be temporarily
discontinued or additional measures to reduce emissions will be undertaken as appropriate.
Demolition of all remaining buildings would take 6 months, but are not likely no begin until 1996.
8-11
-------
Surface Water. With respect to altering the existing drainage system, maintenance of the
existing system would cause the least short-term risk since little, if any, soil would be disturbed.
Slip lining the existing pipes would present some risks to the workers associated with routine
plant site construction but no adverse effects are expected in the general community. This
alternative may present the most risk to the environment if sediments within the drainage pipes
were pushed out of the pipes while inserting the liners. Diversion of off-site surface water run-on
would present additional short-term construction risks and risks to the community since
impiementation of this activity would take place off of the smelter property. Plans to prevent
traffic and road construction hazards would be necessary.
Completely replacing the drainage system could cause dust to be temporarily generated since
some soil excavation and construction will be necessary. This would present short-term risks to
site workers and the near-by residents. If the new drainage system were completely constructed
within the clean soil of the cap, some of this risk (i.e., posed by contaminated soil) would be
eliminated. Many of the original drainage pipes can be sealed and grouted, although, removal
of some of these pipes may be necessary. In this case, some soil and/or slag excavation may
be necessary. A new surface water drainage system would be installed at the same time the soil
cap is being put in place, so sequencing these activities with respect to trucks and workers
would be important.
All of these drainage system cleanup approaches would take 2-3 months to implement.
Replacing the entire system would need to coincide with placing the cap; the other surface water
alternatives would occur before the cap placement.
Surface water treatment also poses short-term risk because it would include the construction of
a new surface water treatment facility and installation of a new drainage system. Even though
transportation routes and operating hours can be established, more noise and truck traffic would
be expected. Constructing a surface water treatment plant would take 9 months from ground
breaking; it would likely be operated forever if source control measures are not also taken.
Ground Water. In the short-term, metal concentrations in ground water are expected to increase
due to the dust-suppression measures (water to control dust enters the soil and moves into
underlying ground water) and to the disturbance of contaminated soil within the aquifer.
Generally, these higher levels are expected to decrease within a year. Regular long-term
monitoring began in the spring 1994, so baseline groundwater data can be used as a reference
to determine if elevated levels are temporary or if additional cleanup measures are necessary.
Due to groundwater diversion measures, the volume of ground water moving through the Site
may be significantly decreased; thereby temporarily increasing the concentration of contaminants
because less dilution would occur.
Shoreline Armoring. Placing larger rocks (riprap) as armoring along the shoreline may result
in the temporary suspension of finer-grained sediments. Temporary release of metals from newly
fractured slag particles in Commencement Bay also may occur if it is necessary to cut back the
angle of the shoreline in order to place the riprap. In addition, armoring with riprap would
significantly impair or destroy much of the intertidal marine biota that currently exists on or along
the shoreline. But riprap can be designed and constructed so that intertidal biota would
recolonize this area. Placing riprap would take approximately 12 months.
Mitigation measures, such as replacing valuable habitat, will be required to replace or augment
any damage incurred with armoring. The extent of replacement or augmentation is not currently
8-12
-------
known; it is estimated that this could take up to two years. In order to mitigate damage caused
by armoring, the creation of pocket beaches, mudflats and vegetated shallows will be evaluated.
Sloping and/or cutbacks may be used and shoreline irregularity can be designed to support
future mitigation of the marine biota. Mitigation may occur at the Asarco Site or another location
off the Asarco property.
(6) Implementabilitv
Treatment of source area soils using a solidification/ stabilization method is implementable.
With the exception of the following practical limitations, excavation of source area soils is
implementable. Some of the practical limitations on excavating soil from the source areas
include:
(a) Natural features, in the arsenic kitchen area soil excavation will be limited due to the
presence of a silt aquitard that is beneath the soils. The aquitard acts as a natural
protective barrier preventing metals from moving into the deepest groundwater aquifer on
the site. EPA believes that it would be detrimental to the lower aquifer to excavate some
or all of this protective silt barrier even though the upper portions of it may contain metals
with elevated concentrations of contaminants.
(b) Man-made features. It is estimated that 15 million tons, or approximately 40 acres, of slag
make up the plant area and the slag peninsula. Previous plant site investigations show
that slag contains up to 25,000 parts per million arsenic, copper and lead. Excavation
of all of this slag is not practicable, however, because of its large volume, the potential
for fractured slag to reach the bay during excavation, and the cost to dispose this volume
of material.
The copper refinery and the fine ore bins areas include both contaminated soil and slag. If, after
soil removal, these areas continue to act as significant sources of groundwater contamination,
EPA will evaluate whether further excavation of slag is necessary.
In the southeast plant area, the combination of organic constituents such as DMA and buried
sawdust appear to enhance the mobility of metals in slag, resulting in high concentrations of
metals in ground water. The sawdust, however, is buried 25 to 30 feet in slag and under
saturated, highly permeable conditions adjacent to the shoreline. Excavation through the slag
to remove the sawdust at these depths is not technically practicable.
Otherwise, soils in the arsenic kitchen, stack hill, cooling pond, copper refinery and fine ore bins
area can be removed with conventional excavation techniques. Diversion trenches and other
techniques to dewater source area soils prior to excavation would need to be used and are
implementable when carefully designed and constructed. Treatment or disposal of contaminated
water resulting from dewatering is implementable.
OCF
An OCF can be built in either the parking lot or arsenic kitchen areas of the Site. One concern
regarding implementability is whether the OCF will have sufficient capacity for on-site soils and
debris. Adding some capacity to the bermed structure in the parking lot and to the circular earth
berm in the arsenic kitchen area prior to completion of the structure may be possible by
8-13
-------
increasing its height. However, the ability to "add" height is limited by the need for structural
stability and by future uses of the Site. Capacity could also be added to the linear design.
Capacity could not be added once the circular concrete tank is constructed.
Off-site disposal would probably require the construction of a staging area. Currently there is no
railroad access to the site and trucks would have to be used to transport excavated soils and
demolition debris to the staging area.
Capping the Site
Capping with either low permeability asphalt or soil is possible. For either type of cap it would
be necessary to regrade the site and assure that several drainage and ponding areas on the site
are eliminated. In general, capping would use common conventional construction techniques
that have been proven reliable. Maintenance would be required for both types of caps but would
be more intensive for the asphalt cap and would require annual crack sealing and seal coats.
Both caps would require guidelines to minimize overall disturbances after they are installed.
Portions of either type of cap would need to be removed if future cleanup activities are necessary
(e.g., installing a ground-water pump and treat system).
Surface Water. Repair or replacement of the existing surface water drainage system is feasible
but must be coordinated with soil excavation and capping activities. Conducting
repair/replacement activities prior to placing the cap would not be difficult to implement. Once
a cap is in place, maintenance, repair or replacement of the existing drainage system or the slip-
lined system would be the most difficult since it would require breaking through the cap.
Sliplining most pipes in the current drainage system is technically feasible for most, but not all,
of the drain pipes. Also, in order to find and access some of the drainage pipes for slip-lining,
it may be necessary to excavate some of the slag. In general, slag excavation is more difficult
than removing soil and newly fractured pieces of slag tend to be more leachable in surface and
ground water. Over the long-term, it would be most practicable to build a new drainage system
for several reasons: (1) blueprints of the new system would be available to future workers,
owners, etc.; (2) a new drainage system can be constructed within the cap thus workers would
not be exposed to contaminated soils beneath the cap when making repairs; and (3) the
protective clay layer of the cap would probably not need to be breached if repairs or replacement
of new drainage pipes are necessary. Property access from adjacent land owners for installation
of some parts of a new system would be necessary.
Diversion of surface water run-on is also technically feasible. Property access for installation of
the surface water diversion system from adjacent land-owners, the Town of Ruston and the City
of Tacoma would be necessary and is believed possible. In addition, the City would have to
verify that there was sufficient capacity at the City and/or Edwards Street outfalls to accept the
diverted surface water.
Demolition. Building demolition and dust suppression are technically and administratively
implementable because they employ conventional trade methods.
Ground Water. Groundwater monitoring is possible and has been conducted on this Site for
many years. Bi-annual monitoring is currently being performed. Quarterly monitoring would
begin as soon as soil excavation is complete and before a cap is installed.
8-14
-------
Shoreline Armoring. See discussion above under "long-term effectiveness and permanence."
(7) Cost
EPA has grouped Asarco's cost estimates into two major categories. The first group contains
these elements of the cleanup that EPA believes are essential under any acceptable cleanup
alternative. The total cost of these "essential elements" is $22.5 million. The estimated costs of
essential elements and the disposal alternatives are shown in Table 8-2.
(8) State Acceptance
The State of Washington concurs with the selected remedy and phased approach described in
this ROD for the former Asarco Tacoma Smelter Facility. The combination of measures to
excavate and consolidate the more highly contaminated soils and debris in a containment facility
with a design equivalent to federal hazardous waste disposal standards, to cap the entire Site,
and to provide certain Site restrictions is appropriate and protective against exposure to such
soils. This current ROD provides for measures to divert surface waters from contact with
contaminants, however, the ROD also provides that additional remedial measures may be taken
on surface water should such further measures be necessary. Ground water will be addressed
in a separate, second phase ROD which will be prepared after the impacts of the soils actions
and water diversion measures under this ROD have been evaluated. This approach and selected
remedy are deemed to be in compliance with the environmental laws and regulations of the
State.
(9) Community Acceptance
EPA held a 90-day public comment period on the cleanup activities for the Site. It received
approximately 900 comments either directly, or through Asarco or the Tacoma City Club. In
addition, EPA has considered public comments in developing its selected remedy by tracking
the land use planning strategy and through contacts with and input from the public. Much of the
public interest appears to be focused on what to do with the Asarco Site after the cleanup,
however, there were many specific comments on the elements of EPA's Preferred Alternative.
EPA believes that its selected remedy will be acceptable to the community based on the public
comment received and their continued involvement in implementation of this cleanup.
To date, the most debated public issue regarding the cleanup itself has been whether to dispose
contaminated soil and other materials in an OCF. Many members of the community, including
the elected leaders and local business leaders, expressed support for an OCF. It appears that
most of the support for on-site disposal was a result of Asarco's promise, in the "Agreement in
Principle," with Ruston, Tacoma, and the Park District, to fund an estimated $15-20 million of
future development activities on the Site.
Although the OCF provision in the Agreement in Principle is not binding on EPA, the
overwhelming community support for an OCF is a significant factor in EPA's final remedy
selection. Several commenters who generally supported an OCF suggested design modifications
for the disposal facility such as treating soil before disposal, constructing separate cells within
the unit for more precise monitoring and segregated disposal of soil (see Section 7.2 for EPA's
responses to these comments). In addition, several commenters encouraged EPA to select the
remedy that would be the most protective of human health and the environment over the long-
8-15
-------
TABLE 8-2. COST
Essential Elements:
Capital
Cost
Operation &
Maintenance
(annual)
Present
Worth
Activity
Plant Site Soils:
Capping the Site
Smelter $6.4 m $6,OOO $6.5 m
Slag
Peninsula $923.0OO $8.600 $1 m
Demolish fine ore bin* building
SI.4 in •••«••••• SO •»••••••••••••• 81.4 fll
Interception trenches
(for dewaterlng and diverting ground water)
$71O,OOO $O $71O.OOO
Surface Water:
Replace drainage system with new drainage
system
$1.4 m $7,200 $1.8 m
Shoreline Armoring:
Shoreline armoring (riprap)
Smelter $3.4 m $12.0OO $3.6 m
Slag
Peninsula $2.5 m $11,000 $2.6 m
Ground Water and Marine Sediments:
Abandon production well
$9,78O $0 $0,780
Monitoring of ground water and sediments
$65O.OOO $263.000 .... $4.7 m
Other Elements:
Institutional controls
$500,000 $0 $500.000
Essential Elements Total $22.5 m
Plant Site Soils
(Excavation/Treatment/Disposal)
Operation &
Capital Maintenance
Activity Cost (annual)
Present
Worth
(a) Excavation and treatment of soil and materials
from source areas; treated soil put back below Site
cap
$38.2 m •«•••»••••••••« $O ••«••.•••» $38.2 m
And
(b) Off-site disposal of debris
$12.7 m* $0 $12.7 m
SUBTOTAL $50.9 m
* Please note that Asarco recently revised Us estimated
cost qfon-slte treatment ($38.2 million) from the
estimate that was used for Alternative PSS-4A In
Section (FJ above ($48.2 million).
Or
(c) Excavation and disposal of soil and debris In RCRA
OCF (no treatment)
$22.6 m $12.000 $22.8 m
Or
(d) Excavation and treatment of soil and disposal of
treated soil and debris In on-slte hazardous waste
landfill
$65.3 m ..$12,OOO $65.5 m
Or
(e) Excavation and treatment of soil and disposal of
treated soil In on-slte solid waste landfill, debris In
off-site hazardous waste landfill
$7O m $12,000 $7O.2 m
Or
(Q Excavation, and off-site treatment and disposal of
soil and debris
$75*1 m ..........**.•• $O «•»»•««•••« $75.1 m
Essential Elements
Excauatiori/Treatment/Disposal
£22.8 million
mmion
£22.5 million
; -v •!•;<
1 (D) 8BO.9 mllllOIi
2.8 million
J.fl million
3.2 million
S.I million
TOTAL Cleanup Costs
•S73.4 million
545.3 million
588 million
£92.7 million
597.6 million
This amount Includes an estimated cost of $200,000 to fill the tunnel. Removing the tunnel is estimated to cost $2.2 million.
The decision whether lo remove or nil will be made during remedial design.
-------
term and not be influenced by Asarco's promise of future development. Based on EPA's belief
that an OCF can be designed to be protective over the long-term and the overwhelming
community support, EPA has significantly modified this component of its Preferred Alternative and
selected disposal in an OCF rather than treatment.
EPA has received other significant comments on its proposed approach to cleanup the Site.
Several natural resource trustee agencies and environmental groups have actively participated
in EPA's technical meetings on cleanup and have submitted written comments. They have stated
that EPA needs to develop an environmentally sound cleanup for the Site that ends current
chemical contamination and that is not compromised or undermined by potential future land
uses. EPA believes that its cleanup meets those objectives and that it will be important for these
groups and local citizens to continue be involved with the review of the remedial design plans
for this Site.
In addition, the Department of Natural Resources, the U.S. Fish and Wildlife Department, Citizens
for a Healthy Bay and Asarco raised questions regarding the need for armoring the slag based
on the amount of slag erosion and the design of shoreline armoring. Although it is visually
apparent that slag is eroding, EPA agrees with the commenters that the extent and location of
erosion should be determined first (e.g., using durability tests). After this step, EPA has
determined that additional design studies will be conducted to determine the location and extent
of armoring, including cutbacks or excavation in order to anchor the base of the armoring.
EPA also received many comments that encouraged site cleanup to progress as quickly as
possible. Therefore, EPA has decided that if the Site is ready to be capped, but all of the
Ruston/North Tacoma residential soils have not been removed from the Study Area, the Site will
be capped and an appropriate off-site disposal facility will be selected for these soils as per
Ecology's dangerous waste exemption.
8-17
-------
9.0 THE SELECTED REMEDY
EPA's selected remedy combines elements from several of the media-specific alternatives
described above. The selected remedy meets the requirements of the two mandatory threshold
criteria, protection of human health and the environment and compliance with ARARs, and
provides the best balance of benefits and trade-offs for the former Asarco Tacoma Smelter site.
Several proposed actions described in EPA's Preferred Alternative have either been initiated or
completed since the public comment period. Ground water and sediments monitoring is
underway (October 1994). In addition, EPA has allowed Asarco to abandon the production well
(December 1994).
The following are the individual components of EPA's Selected Remedy.
9.1 PLANT SITE SOILS
9.1.1 Excavate Soil and Granular Slag From Five Source Areas9
Contaminated soil that fails the TCLP test in the stack hill, cooling pond and arsenic kitchen
areas and contaminated soil and granular slag from the copper refinery and fine ore bins building
areas will be excavated to the extent feasible. The party (EPA or Asarco) conducting the cleanup
will perform the following activities during soil excavation:
(a) Asarco will submit the additional soil borings data required under the AOC
(October 1994) to EPA during remedial design.
(b) Use interception trenches, or other applicable technology, to divert ground water
where necessary to allow for easier excavation of soils.
(c) Control soil erosion and contaminated stormwater runoff by using best
management practices (for example, sediment ponds, silt fences, diversion
ditches, cut and fill slopes).
(d) Confirm that all necessary excavation has been performed.
(e) Remove or fill the car tunnel to allow for future land use plans. Whether the
railroad tunnel will remain will be determined after discussions with Burlington
Northern railroad.
(f) Conduct a wetlands assessment at the Site.
(g) Use capping material (see Section 9.1.3) to fill and regrade the excavated areas.
Q
Excavation of the sixth source area, the southeast plant area, is impracticable (see "Implementability" in Section
8.0 above.)
9-1
-------
9.1.2 On-Site Disposal
(a) Construct an OCF northeast of the arsenic kitchen area. The OCF will be an
approximately 600-foot diameter circular earth berm with an estimated capacity of
240,000 cubic yards. The liner, cap, leak detection, collection and removal
system, leachate collection and removal system and surface run-on and run-off
control systems will meet federal and state standards for a hazardous waste
landfill, see performance standards in Section 9.9.
(b) Construct surface water and groundwater diversion controls (for example,
interception trenches and grout wall) around the OCF to prevent surface water
and ground water from coming into contact with the OCF.
(c) Dispose the soils excavated from the source areas, the bricks temporarily stored
on the stack hill, and the hazardous waste materials temporarily stored in the fine
ore bins building in the OCF. Materials that are not on-site as of the date of this
ROD will not be disposed in the OCF.
(d) Crush or shred over-sized debris prior to disposal.
(e) Conduct the appropriate seismic studies in order to construct the OCF to
withstand earthquakes and landslides to the extent practicable.
(f) Monitor air quality to ensure that dust is not generated when soil and debris are
excavated and disposed in the OCF (see other "safety measures" below).
(g) Do not dispose wet materials, including marine sediments, in the OCF.
(h) In the design plans for the OCF, allow for a limited amount of additional capacity
in the event more than the estimated 160,000 cubic yards of soil or 80,000 cubic
yards of demolition debris require disposal. In the event the amount of waste to
be disposed is greater than the maximum capacity of the OCF, this material will
be disposed off-site in an appropriate facility.
(i) Develop a plan for the closure of Ruston Way adjacent to the Site when
construction of the OCF occurs.
(j) Maintain the OCF in perpetuity.
9.1.3 Capping the Site (PSS and slag and the slag peninsula)
After excavation of materials from the source areas, cap the entire Site (with the exception of the
OCF and the possible exception of the Stack Hill area, see performance standards below) with,
from bottom to top, soil excavated during the residential Study Area cleanup, a low permeability
clay liner, a gravel drainage layer, at least 12 inches of clean topsoil (i.e., below MTCA residential
cleanup levels), and sod, see Figure 7-1. The cap will meet the performance standards identified
in Section 9.9. Capping of the Site includes the following elements:
(a) Grade and prepare the Site for capping, including grading the ramp constructed
from Thome Road slag. Use contaminated residential soils as a sub-base for the
9-2
-------
cap only in areas of the Site where they will not come into contact with ground
water, for example, the slag portions of the Site. Stockpile contaminated
residential soils on-site until they are ready to be used for capping.
(b) If the Site is ready to be capped, but not all of the residential soils have been
excavated from the Ruston/North Tacoma Study Area, an appropriate off-site
disposal facility (see Ecology's dangerous waste exemption dated December 20,
1993) will be selected. Whether a temporary staging area, on- or off-site, will be
necessary will be determined during remedial design.
(c) Assure that existing asphalt and building pads on the site will not cause pooling
and standing water beneath the cap. Eliminate pooling of surface water on the.
surface of the cap.
(d) Incorporate planning for future development, such as site grading, utilities, surface
water drainage systems, landscaping and terracing, into design and construction
of the cap to the extent possible.
(e) Fence and plant low lying shrubs in areas determined to be too steep to cap (e.g.,
the east and west gully slopes of the stack hill). Apply a geotextile material to the
soil to provide erosion protection, as well as a means for supporting vegetative
development.
(f) Perform mitigation activities if wetlands or aquatic ecosystems are adversely
impacted by soil removal or capping. Evaluate the feasibility of setting aside
areas on the slag peninsula to allow marine birds to feed and roost.
(g) Maintain the cap.
9.2 DEMOLISH REMAINING BUILDINGS AND STRUCTURES
Demolish all of the remaining buildings and structures on the smelter site. The sequence of
building demolition and construction of the OCF will be determined during remedial design.
(a) Prior to demolition, inspect all remaining buildings and structures to locate and identify
all asbestos-containing material (ACM). Remove ACM from the on-site buildings and
dispose of it off-site in accordance with applicable federal and state requirements.
(b) Vacuum and wash buildings and structures at the Site before beginning demolition
activities. Wash areas of structures containing dust that are inaccessible for vacuuming
to curtail dust emissions. Collect wastewaters generated from the dust suppression
system at each demolition site and route to a wastewater evaporation system, or dispose
in an appropriate manner.
(c) Reactivate the air monitoring stations which were used during previous demolition
activities (e.g., Site Stabilization-Phase 2).
(d) Use conventional trade demolition techniques for the demolition of, or dismantling of the
remaining on-site structures. Use conventional equipment, such as shears, grapples,
loaders, and cranes, where necessary to safely and efficiently dismantle the structures.
9-3
-------
(e) Sample all debris from demolition of remaining buildings before disposal. Dispose any
material other than wood waste that is determined to be hazardous waste using the TCLP
test (e.g., steel, concrete, metal) in the OCF. Dispose debris that is not hazardous waste,
but fails the wipe test, either off-site pursuant to a dangerous waste exemption issued by
Ecology dated May 23,1994, or in the OCF. Where appropriate, pressure wash debris.
Recycle metal materials that pass both TCLP and the wipe test. Dispose all wood debris
in an appropriate off-site disposal facility.
9.3 SURFACE WATER
(a) Plug and abandon or remove the entire existing surface water drainage system and install
a new drainage system, including outfalls, in the smelter site cap to collect or divert water
that runs onto the Site from the off-site drainage basins and from precipitation that
originates on the site. In addition, ensure that seeps on the stack hill and other areas of
the Site do not run on the Site.
(b) Monitor surface water quality during and after implementation of repair and replacement
of the drainage system, soil removal, and capping. If surface water quality continues to
exceed federal and state standards, treatment of surface water will be evaluated.
(c) Maintain the surface water drainage system.
9.4 SHORELINE ARMORING
Shoreline armoring of the plant site and slag peninsula, see Figure 7-3.
(a) Determine the extent of shoreline erosion by performing durability tests on the slag (e.g.,
specific gravity, absorption, accelerated expansion, abrasion tests, freeze/thaw test) and
visual observation.
(b) Determine where shoreline armoring should be placed based on erosion tests.
(c) Anchor armoring on the slag face on the bayward side of the slag face along the plant
site and slag peninsula, as appropriate, to prevent erosion of the slag due to currents,
waves and tidal action. The interior portion of the Yacht Club basin will not require
armoring.
(d) Remove abandoned structures, debris and waste (treated pilings, cables) near the
shoreline along the slag peninsula as necessary.
(e) Mitigate or compensate for shoreline armoring activities that may result in adverse
impacts to intertida! habitat. Identify and analyze potential mitigation measures following
the guidelines under the Clean Water Act and the state's hydraulic code rules. EPA will
work during the design phase of the cleanup with the federal and state trustees of natural
resources to develop a mitigation plan.
Required mitigation measures to remedy the impact to the marine environment from
shoreline armoring may include shoreline pull back and sloping, development of pocket
beaches, mudflats, vegetated shallows, and shoreline irregularity, and may occur on-site
or off the Asarco property.
9-4
-------
(f) Maintain the shoreline armoring.
9.5 GROUND WATER AND MARINE SEDIMENTS
(a) Continue monitoring surface water and ground water and sampling marine sediments.
Future sampling programs may include further monitoring of marine sediments to evaluate
whether discharges from the Site after this cleanup are continuing to contaminate the
sediments. Remedial measures to address offshore sediments will be included in a
separate ROD.
(b) To control contaminants from entering the deeper ground water, EPA directed Asarco in
December 1994 to "abandon" the production well, a deep well in the central area of the
site that supplied water for smelter activities. Abandoning the well involved making small
holes in and filling the well casing (the walls of the well) with grout, a concrete-like
material.
9.6 OTHER ELEMENTS OF THE SELECTED REMEDY
9.6.1 Safety Measures
During cleanup, safety measures include, at a minimum, air monitoring with Hi-vol and PM10 air
paniculate monitors, using dust suppression techniques during excavation and disposal activities,
lining and covering truck beds when transporting contaminated materials on public roads,
removing soils from truck wheels before they travel on public roads (for example, from the stack
hill area to the lower Site), developing a transportation plan to establish local truck routes to
minimize disruption to the community, and temporarily storing hazardous waste on-site in
compliance with waste pile requirements.
9.6.2 Integrating Cleanup With Land Use Plans
Develop an enforceable program of restrictions and guidelines to supplement the actual cleanup
activities. Such measures are necessary to ensure that development activities do not affect the
long-term effectiveness of the cleanup and will include, but are not limited to the following:
(a) Establish a maintenance and monitoring program to ensure the continued integrity of the
low-permeability soil cap, the OCF and shoreline armoring.
(b) Establish guidelines to ensure that future cleanup measures (including, if necessary,
remediation of ground water and/or surface water) will not be prevented or hindered by
development activities.
(c) Establish guidelines for conducting construction and maintenance activities to ensure that
little or no remaining contamination is exposed or released during future (post-cleanup)
excavation. Develop additional guidelines to identify the appropriate actions if
contaminant exposure or release occurs (e.g., Asarco's responsibility for disposal of
contaminated soil). Activities addressed by these procedures will include installation of
underground utilities, basements or elevator shafts and roadways.
(d) Use deed restrictions to prohibit the use of ground water at the Site and to ensure
compliance with the program and guidelines described in (a), (b), and (c) above.
9-5
-------
(e) Develop public educational materials and markers or signs for future users and occupiers
of the Site. The materials and markers or signs will describe the cleanup and explain
what the users and occupiers should and should not to maintain the effectiveness of the
cleanup.
9.6.3 Periodic Review
The protectiveness of the cleanup will be reviewed at least every five years.
9.7 CLEANUP SCHEDULE
EPA estimates that the selected remedy will take five years to complete. It is possible that soil
removal and/or capping in one area of the Site (for example, the stack hill or parking lot) can be
completed so that development activities can start prior to completion of the cleanup of the entire
Site.
EPA will not allow development to begin in any area, however, until it determines that cleanup
in that area is complete, that development is safe given cleanup activities taking place elsewhere
on-site, and that development would not interfere with potential cleanup measures in the future.
9.8 COST OF THE SELECTED REMEDY
EPA estimates that the cost to perform the Selected Remedy will be $45.3 million. These costs
are estimated and are considered to be accurate to within -30% to +50%. Costs are described
using the present worth methodology with a discount rate equal to five percent. The cost
estimate includes direct and indirect capital costs, as well as annual operations and maintenance
costs. Operation and maintenance (O & M) costs have been estimated for 30 years but O & M
activities will be required in perpetuity. See Section 8(7) and Table 8-2 for a more complete
breakdown of costs.
9.9 PERFORMANCE STANDARDS
The final Site cleanup levels will be adjusted so that the overall cancer risk from all of the media
and the exposure pathways will be equal to or less than 1 x 10"5 and the non-cancer effects will
be equal to or less than 1.0
PLANT SITE SOILS
In order to obtain the Cleanup Objectives described in Section 6.7, performance standards
and/or remediation goals have been established for each medium that will be cleaned up.
Source Areas. The boundaries of the source areas that require excavation generally will be
defined by soils that exceed hazardous waste levels as determined by the TCLP test, see below,
and by practical limits on excavation, see Section 8 - Implementability. If soils outside the source
areas exceed hazardous waste levels, EPA will evaluate whether further excavation is warranted.
These numbers do not represent remediation goals but rather serve as markers for areas to be
excavated. Because all areas of the Site will be addressed by soil/slag removal, the OCF, or the
Site cap, specific remediation goals for PSS have not been selected.
9-6
-------
Chemical mq/L
Arsenic 5.0
Cadmium 1.0
Chromium 5.0
Lead 5.0
Mercury 0.2
Selenium 1.0
Silver 5.0
Site Cap
The entire site, excavated source and non-source areas, will be capped. The cap will meet the
requirements described herein. If, however, after excavation, soil in the stack hill area is below
levels comparable to the action levels set for the Ruston/North Tacoma cleanup, a less stringent
cap using only soil and a vegetative cover will be required. "Comparable" levels will be
determined by EPA and Ecology.
Cover System
A low hydraulic conductivity layer including a minimum of one (1) feet of compacted soil over the
soil and slag with a maximum hydraulic conductivity of 1 X10*' cm/sec, which is to be designed,
constructed, operated and maintained to maximize removal of water by the overlying drainage
layer and to minimize infiltration of water into the contaminated soil, and slag.
A drainage layer of at least .5 feet or greater granular drainage materials with a hydraulic
conductivity of 1 X 10~2 cm/sec or equivalent. The drainage layer, which is placed above the low
hydraulic conductivity layer, must be designed to minimize the amount and residence time of
water coming into contact with the low hydraulic conductivity layer, thereby decreasing the
potential for leachate generation.
Atop cover comprised of two (2) layers. The top component is vegetation designed to impede
erosion while still allowing surface runoff from major storm events. The lower component is a
minimum of one (1) foot of soil capable of sustaining plant species that will minimize erosion.
The cover system must be designed and constructed to meet the following performance
standards:
(a) Prevent direct contact of people, animals, and surface water with contaminated soils and
slag.
(b) Prevent contaminated soil from being wind-blown.
(c) Provide long-term minimization of migration of liquids through the Asarco Smelter site.
(d) Function with minimum maintenance.
(e) Promote drainage and minimize erosion or abrasion of the cover.
(f) Accommodate settling and subsidence so that the cover's integrity is maintained.
9-7
-------
(g) • A construction quality assurance (CQA) program shall be established for the cover system
to ensure that the constructed cover meets or exceeds all design criteria and
specifications.
Modifications of the cover system in areas where development will occur will need to be
approved by EPA on a case-by-case basis.
Post Closure Care
Maintain the integrity and effectiveness of the final cover, including periodic inspections and
making repairs to the soil cap as necessary to correct the effects of settling, subsidence, erosion,
or other events.
Prevent run-on and run-off from eroding or otherwise damaging the final cover.
ON-SITE CONTAINMENT FACILITY
The following performance standards are based on requirements in 40 C.F.R. Part 264 for
hazardous waste landfills.10
Bottom Liner System (40 CFR Sections 264.301 (c)(i), 264.301 (a))(1)(i), (H), and (Hi))
A composite top liner including a minimum of one (1) foot of compacted soil with a maximum
hydraulic conductivity of 1 X 10"7 cm/sec overlain by a flexible membrane liner.
A composite bottom liner including a minimum of three (3) feet of compacted soil with a
maximum hydraulic conductivity of 1 X 10"7 cm/sec overlain by a flexible membrane liner
designed to prevent the migration of hazardous constituents into the upper components.
The upper component of the top and bottom composite liner will be designed and constructed
to prevent migration of hazardous constituents into this component during the active life and
post-closure period. The lower component of the top and bottom composite liner will be
designed and constructed to minimize the migration of hazardous constituents ft a breach in the
upper component were to occur.
The liner system shall be designed and constructed to comply with 40 CFR Sections 264.301
(a)(1)(i), (ii), and (iii) to assure that it is engineered to withstand the chemical and physical
stresses it will be subjected to while containing the waste. The liner system shall be located,
designed, constructed, and operated to be completely above the seasonal high water table.
Leachate Collection and Removal System (40 CFR Sections 264.301 (c) (2)) and
264.301 (c) (3) (iii) and (iv))
The leachate collection and removal system immediately above the top liner must be designed,
constructed, operated, and maintained to collect and remove leachate from the landfill during the
active life and post-closure care period. It shall be designed and operated to ensure that
leachate depth over the liner does not exceed one (1) foot.
10 Specific references to federal regulations only are set forth in this section. The requirements of this section are
intended to also comply with state requirements for landfills set forth in WAC 173-303-665.
9-8
-------
The leachate collection and removal system immediately above the top finer shall be designed
and constructed to comply with 40 CFR Sections 264.301 (c)(3) (iii) and (iv) to assure that it is
engineered to withstand the chemical and physical stresses it will be subjected to and to
minimize clogging.
Whether leachate will be treated and discharged on-site or disposed off-site will be determined
during remedial design.
Leak Detection Collection and Removal System (40 CFR Sections 264.301 (c) (3) (i-v),
264.301(0} (4), 264.302, and 264.304).
The teak detection, collection and removal system in between the liners shall be constructed with
a bottom slope of one percent or more of granular drainage materials with a hydraulic
conductivity of 1 X10'2 cm/sec and a thickness of 12 inches or more, or with synthetic or geonet
drainage materials with a transmissivrty of 3 X 10"5 m2/sec or more and it shall be constructed
with sumps and liquid removal methods that shall be operated to minimize the head on the
bottom liner system in accordance with 40 CFR Sections 264.301 (c)(3)(v) and 264.301 (c)(4). An
action leakage rate and response action plan will be established for the OCF in accordance with
40 CFR Sections 264.302 and 264.304 to address design flow rates in the leak detection system
which will result in a head greater than a foot on the bottom liner system.
The leak detection, collection and removal system in between the liners shall be designed and
constructed to comply with 40 CFR Sections 264.301 (c)(3)(iii) and (iv) to assure that it is
engineered to withstand the chemical and physical stresses it will be subjected to and to
minimize clogging.
Surface Run-on Control System (40 CFR Sections 264.301 (g) and (i))
Design, construct, operate and maintain a run-on control system capable of preventing flow onto
the active portion of the landfill during peak discharge from at least a 25-year storm. Collection
and holding facilities which are associated with this system must be emptied expeditiously after
storms to maintain design capacity of the system.
Surface Run-off Control System (40 CFR Sections 264.301 (h) and (i))
Design, construct, operate, and maintain a run-off management system to collect and control at
least the water volume resulting from a 24 hour, 25-year storm. Collection and holding facilities
which are associated with this system must be emptied expeditiously after storms to maintain
design capacity of the system. Discharges to Commencement Bay shall comply with surface
water performance standards.
Control of Paniculate (40 CFR Section 264.301 (j))
The OCF shall be operated to control wind dispersal of contaminated soil, slag and debris placed
in it.
9-9
-------
Monitoring, Inspection and Construction Quality Control (40 CFR Sections 264.303, and
264.19)
A CQA program shall be established for the OCF to ensure that the constructed unit meets or
exceeds all design criteria and specifications in accordance with 40 CFR Sections 264.19 and
264.303. The landfill systems must be inspected during operation and the leak detection system
after closure. Inspection of the landfill during operations will be in accordance with 40 CFR
Section 264.303.
Cover System (40 CFR Sections 264.310 and 264.19)
A composite low hydraulic conductivity layer including a minimum of two (2) feet of compacted
soil over the waste with a maximum hydraulic conductivity of 1 X 10'7 cm/sec overlain by a
flexible membrane liner designed, constructed, operated and maintained to maximize removal of
water by the overlying drainage layer and to minimize infiltration of water into the contaminated
soil, slag and debris in the OCF.
A drainage layer of one (1) foot or greater granular drainage materials with a hydraulic
conductivity of 1 X10*2 cm/sec and a thickness of 12 inches or more, or with synthetic or geonet
drainage materials with a transmissivity of 3 X 10"5 m2/sec or more overlain by filter layer to
prevent clogging of the drainage layer. The drainage layer, which is placed above the composite
low hydraulic conductivity layer, must be designed to minimize the amount and residence time
of water coming into contact with the composite low hydraulic conductivity layer, thereby
decreasing the potential for leachate generation.
A top cover layer comprised of two (2) layers. The top component is vegetation designed to
impede erosion, but allowing the surface runoff from major storm events. The lower component
is a minimum of two (2) feet of soil capable of sustaining plant species that will minimize erosion.
The cover system must be designed and constructed to meet the following performance
standards specified under 40 CFR Sections 264.111 and 264.310:
(a) Minimize the need for further maintenance.
(b) Control, minimize or eliminate, to the extent necessary to protect human health and the
environment, post-closure escape of hazardous waste, hazardous constituents, leachate,
contaminated run-off, or hazardous waste decomposition products to the ground or
surface waters or to the atmosphere.
(c) Provide long-term minimization of migration of liquids through the closed OCF.
(d) Function with minimum maintenance.
(e) Promote drainage and minimize erosion or abrasion of the cover.
(f) Accommodate settling and subsidence so that the cover's integrity is maintained.
(g) Have a permeability less than or equal to the permeability of any bottom liner system or
natural subsoils present.
9-10
-------
(h) A CQA program shall be established for the OCF cover system to ensure that the
constructed cover meets or exceeds all design criteria and specifications in accordance
with 40 CFR Section 264.19.
Closure Certification and Post Closure Care of the OCF (40 CFR Sections 264.310,264.115,
264.116, 264.117, 264.118, 264.119, and 264.120)
The closure certification, monitoring, operation, maintenance and record keeping requirements
of 40 CFR Sections 264.310, 264.115, 264.116, 264.117, and 264.118 must be adhered to after
closure of the OCF. The post-closure period for the OCF shall be indefinite.
DEMOUTION/EXCAVATION/DiSPOSAL
(a) Air. Hi-vol and PM10 air particulate monitors will be used to confirm that the following
levels are not exceeded.
Chemical ma/L11
Arsenic 0.2
Lead 0.75
PM10 75
(b) Dust Control. A "no-visible dust" standard will be in effect.
SURFACE WATER
The remedial goals identified for surface water in EPA's September 1993 document entitled,
"EPA's Preliminary Remedial Action Objectives," (Table 9-1) are the performance standards that
surface water discharging into Commencement Bay must meet. Whether a mixing zone for point
source discharges is necessary will be determined during remedial design.
Shoreline Armoring
Minimize the release of slag particles into the bay.
Ground Water
The preliminary remediation goals for Class III ground water impacting surface water (water that
is not suitable for drinking) (Table 9-2) will be used as a benchmark to determine the
effectiveness of source control activities. Final groundwater remediation goals will be selected
in a final ROD for ground water.
11 The arsenic level is based on 5 x 10~5 risk-based levels over a 10 year period. The lead level is based on 1/2
the allowable PSAPCA level. PM10 levels are based on half of the quarterly allowable 24-hour allowance.
9-11
-------
TABLE 9-1. REMEDIATION GOALS FOR SURFACE WATER IMPACTING PUGET SOUND
CONTAMINANT
Arsenic
Beryllium
Cadmium
Chromium VI
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Total Petroleum
Hydrocarbons
Aniline
4-Chloroaniline
N-Methylaniline
N-Nitrosodi-
phenylamine
REMEDIATION
GOAL
(H9/L)
2.0
1.0
8.0
50
10.0
5.8
0.2
7.9
71
1.2
76.6
10,000.0
1.3-37
29-61
160
10
REFERENCE
MTCA B, PQLa based on the CRDLb
MTCA B, CRDL
MTCA B, WQS for aquatic life
MTCA B, WQC/WQS for aquatic life
MTCA B, PQL based on EPA Method 1220.2
which has an IDL of 1 .0 to 2.0
MTCA B, WQS
MTCA B, PQL based on CRDL
MTCA B, WQS
MTCA B, WQC/WQS for aquatic life
MTCA B, WQS
MTCA B, WQS
MTCA B, Ecology's Guideline for Discharges
Containing Oil and Grease of Mineral Origin
Preliminary criteria for the protection of aquatic
life
Preliminary criteria for the protection of aquatic
life
MTCA B, risk-based
MTCA B, PQL based on CRDL
Practical Quantitation Limit
b Contract Required Detection Level
NOTE: If use of a mixing zone is appropriate, the compliance point for the surface water discharge would be at the
edge of the designated mixing zone in Puget Sound. These values have not been adjusted to take into
account the background levels of these contaminants in uncontaminated surface water on land or in surface
water in Puget Sound.
9-12
-------
TABLE 9-2. PRELIMINARY REMEDIATION GOALS FOR CLASS III GROUND WATER
IMPACTING SURFACE WATER IN PUGET SOUND
CONTAMINANT
Arsenic
Beryllium
Cadmium
Chromium VI
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Total Petroleum
Hydrocarbons
Aniline
4-Chloroaniline
N-Methylaniline
N-Nitroso-
diphenylamine
EPA
REMEDIATION
GOAL
(ug/U
6
1.0
8.0
50
40
12
0.2
0.2
71
1.2
98
10,000.0
1 .3-37
29-61
160
10
REFERENCE
MTCA B, background [MTCA B number
(10"6 risk) for fish consumption is 0.14
MTCA B, POL based on CRDL [MTCA B
number (10"6 risk) for fish consumption is
0.08
MTCA B, Water Quality Standards (WQS) for
aquatic life
MTCA B, Water Quality Criteria (WQC)/WQS
for aquatic life
MTCA B, background (WQS is 2.5)
MTCA B, background (WQS is 5.8)
MTCA B, PQL based on CRDL (WQS/WQC
are 0.025)
MTCA B, background (WQS is 7.9)
MTCA B, WQC/WQS for aquatic life
MTCA B, WQS for aquatic life
MTCA B, background (WQS is 76.6)
MTCA B ARAR, Ecology Guideline for
Discharges Containing Oil and Grease of
Mineral Origin (using TPH analysis)
Preliminary criteria for the protection of
aquatic life
Preliminary criteria for the protection of
aquatic life
MTCA B, risk-based (10*)
MTCA B, PQL based on CRDL [MTCA B
number (10"6 risk) for fish consumption is
6.1
9-13
-------
10.0 STATUTORY DETERMINATIONS
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy will eliminate, reduce, or control exposure to contaminants on the Site at
the former Asarco Smelter facility. Risks from exposure to soil, slag, and surface water will be
eliminated by removing and isolating source area soils, capping contaminated soil and slag,
demolishing the remaining buildings, replacing the existing drainage system with a new drainage
system and armoring portions of the shoreline.
An enforceable program consisting of legal, engineering and administrative restrictions and
guidelines will also be developed to supplement the actual cleanup activities. This program is
required in order to assure that the cleanup activities remain protective (e.g., cap, armoring and
OCF maintenance), to prohibit certain activities (e.g., drinking ground water), and to address the
residual risk of the contaminants left on site.
Accordingly, the selected remedy is protective of human health and the environment.
10.2 COMPUANCE WITH ARARs
The selected remedy will attain ARARs under federal and state law (see Table B-8 in Appendix
B). Compliance with* requirements for selection of cleanup actions under MTCA are discussed
in Section 10.4 below. The interim measures waiver will be used for the state ARAR for restoring
ground water. EPA will select a final remedial action for ground water that will attain the ARAR
or provide a justification for its waiver.
10.3 COST-EFFECTIVENESS
The cost of the selected remedy is proportional to its overall effectiveness and it represents a
reasonable value for the money to be spent. EPA made this determination by comparing the
cost and effectiveness of treating soil versus disposing untreated soil and debris in an OCF
based on the significant community support for on-site disposal.
EPA believes that excavating soil from the source areas is the key step to reducing contaminant
concentrations in ground water and surface water. How to dispose of the contaminated soil has
been the most significant issue in this cleanup. Treating contaminated soil with a
solidification/stabilization process will bind contaminants in a cement-like mixture (but will not
detoxify or reduce concentrations). Contaminants in treated soil are unlikely to move out of the
soil into other media. The treated soil can be used as sub-base for a site cap. The estimated
cost of treating soil is $38.2 million. If soil treatment were selected, the estimated cost for off-site
disposal of contaminated debris (which cannot be treated) is $12.7 million, for a cost of $50.9
million.12
Both soil and debris can be disposed in an OCF. The OCF option will attain a similar objective
to treatment, which is minimizing the movement of contaminants into other media, by containing
the contaminated soil in a large on-site landfill. The most significant technical difference between
12 The $50.9 million is in addition to the estimated cost of $22.5 million for the "essential elements" of the remedy
(see Section 8.7 above).
10-1
-------
treatment and the OCF is that active measures, other than monitoring, would not have been
necessary for the treated soil but a permanent operation and maintenance (O&M) program is
required to maintain the integrity of the OCF. The O&M program will be a legally enforceable
component of the cleanup. The estimated cost for disposal in an OCF is $22.8 million.
The difference in estimated costs between the treatment and OCF options is $28 million. EPA
concludes that because the ability of the OCF to isolate contaminants from the environment is
as effective as treating contaminated soil, and because of the strong community support for on-
site disposal, the OCF is a cost-effective solution.
It should be noted that the estimated cost to transport and dispose soil and debris in an off-site
landfill is $75.1 million, over $50 million higher than the OCF option. Although off-site disposal
would permanently avoid all potential problems associated with leaving contamination on-site,
EPA believes that, in comparison, the OCF still represents the best value for the money. This
determination is also based on the fact that significant contamination, e.g., 15 million tons of slag
would remain at the Site even if contaminated soils from the source areas were disposed off-site.
Off-site disposal does not mean that problems at the Site are eliminated.
EPA has determined that the other components of the selected remedy are also cost-effective
because they represent a reasonable cleanup value for the money.
10.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
The NCP states that this requirement is fulfilled by selecting the alternative that is protective,
complies with ARARs, and provides the best balance of trade-offs in terms of the five balancing
criteria (numbers 3 through 7 in Section 8.0). The modifying criteria (numbers 8 and 9) shall also
be considered. Under MTCA Section 173-340-360(5), very similar criteria are used to select
permanent solutions to the maximum extent practicable and to select from among the hierarchy
of cleanup technologies in 173-340-360(4).
Again, the crucial decision at this Site is how to manage soil excavated from the source areas
and demolition debris. The alternatives range from treating soil to disposing soil and debris,
without treatment, in an OCF, to disposing soil and debris off-site. EPA believes that each of
these alternatives is protective and complies with ARARs. For the following reasons, EPA has
determined that disposing soil and debris, without treatment, in an OCF provides the best
balance of trade-offs considering the balancing and modifying criteria, (e.g., community
acceptance).
The most important differences in the alternatives are with respect to long-term effectiveness,
cost, and community acceptance. Treating soils with a solidification/stabilization technology
appears to be effective in preventing the movement of contaminants out of soils into other media.
Treatment will not destroy or reduce the toxicity of contaminants, thus requiring long-term
monitoring to ensure that treatment remains effective. Treated soils might have been put back
on the Site as sub-base for a cap but not in areas where construction is likely to occur, making
it less accommodating of future uses than an OCF. The estimated cost of treatment is $38.2
million, plus $12.7 million for disposing debris that cannot be treated, for a total of 50.9 million.
In addition, during the 90-day public comment period, approximately 830 out of 900 local
residents, businesses and local officials supported an OCF and future development of the Site.
10-2
-------
Disposing soil and debris in an off-site landfill would be the most effective solution for the Site
over the long-term because the problems associated with on-site management of this soil and
debris would be eliminated. It is, however, important to remember that regardless of which
alternative is selected, an estimated 15 million tons of siag, which contains hazardous
substances, and contaminated soil not within the source areas will remain at the Site because
it is impracticable to remove and dispose it elsewhere. Although slag and non-source area soil
currently contribute less than the source areas to groundwater contamination, these are still
contaminated areas that cannot be left alone. Their contribution to groundwater contamination
can further be reduced by capping these areas. Thus, even if EPA selected off-site disposal of
soil and debris, long-term management of the contamination that remains on-site would still be
an important component of EPA's cleanup. Off-site disposal, excluding management of
remaining slag and soil on-site, is estimated to cost $75.1 million. In addition, 830 out of 900
commenters supported an OCF and future development of the Site.
The OCF option, which consolidates-the most contaminated soil and debris in a landfill on-site,
is an effective solution over the long-term if it is designed and constructed properly and
continuous attention is paid to its operation and maintenance.13 Its estimated cost of $22.8
million is significantly less than the $50.9 million for treatment and the $75.1 million for off-site
disposal. Further, Asarco has demonstrated that the OCF can be constructed on-site so as not
to interfere with plans for future development of the property. Comments from individuals and
groups in the community overwhelmingly endorsed this approach because of their desire to see
such development at the Site. Accordingly, because it is an effective method to isolate
contaminants from the environment, costs significantly less than other options, and is most
accommodating of future uses desired by the community, EPA has determined that the OCF
option provides the best balance of tradeoffs and, therefore, is the permanent solution to the
maximum extent practicable for cleanup of the Asarco Site. For the same reasons, under MTCA,
selecting disposal in an engineered facility is appropriate even though immobilization of
hazardous substances is more preferred in the regulations.
EPA has determined that other components of the selected remedy are also permanent to the
maximum extent practicable.
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT.
As explained in Section 10.4 above, none of the components of the selected remedy will satisfy
the preference for treatment. If treatment of surface water is necessary in the future, the
preference for treatment would be satisfied.
13 EPA's analysis shows that treating soil before it is placed in an OCF does not provide significant benefits in
terms of reducing contaminants moving into the environment should there be a structural failure of the OCF in the
future. Therefore, this option has not been selected. See Section 7.2 and Appendix D.
10-3
-------
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
In the Proposed Plan, EPA recommended treatment of contaminated source area soils because
treated soils did not significantly leach above regulatory levels and EPA believed that the
community and the elected officials were strongly opposed to an OCF based on meetings held
in the community over the past several years. During the public comment period on the
Proposed Plan, EPA received comments from the majority of the public and their elected
representatives strongly encouraging the selection of an OCF in lieu of soil treatment
(solidification/stabilization) and disposal.
The two approaches for these soils are comparable in terms of their overall protectiveness but
differ primarily with respect to their cost and compatibility with future land use and community
acceptance. For the reasons stated above, EPA's selected remedy provides for the on-site
containment of excavated source area soils. Soils will not require treatment before disposal in
the OCF.
In the Proposed Plan, EPA recommended that the slag shoreline along the Asarco Site and the
slag peninsula be armored with riprap. During the public comment period, several commenters
wondered whether the shoreline was eroding, whether the erosion was causing an adverse
impact on the adjacent marine sediments and if more harm than good would be caused if by
adversely impacting existing habitat which lived on the current slag face.
Several commenters questioned whether the slag shoreline was eroding, whether the eroded slag
particles caused an adverse impact on the adjacent marine environment, and why the shoreline
needed to be armored since it is already providing a suitable habitat for marine biota. If shoreline
armoring was determined to be necessary, commenters also questioned how it would be
anchored to the existing slag face and why riprap (large rocks) was selected instead of artificial
beach nourishment (small rocks and sand) to armor the slag.
After evaluating the comments received and finding out that a shoreline monitoring station,
consisting of large rocks piled against the shoreline was destroyed by tidal action and strong
shoreline currents, EPA still believes that some amount of shoreline armoring will be necessary
to prevent erosion of slag particles, which cause adverse effects to marine organisms in the Bay.
However, EPA has determined that before the design of the shoreline armoring begins, additional
data should be collected to determine (1) the extent of shoreline erosion; (2) how and where
armoring should be placed; and (3) the impact of armoring to the existing marine biota versus
the impact of not armoring slag to the marine biota over time. EPA will encourage other state
and federal resource agencies and community groups to participate in the development of the
shoreline armoring.
11-1
-------
APPENDIX A
RESPONSIVENESS SUMMARY
-------
ASARCO
RECORD OF DECISION
RESPONSIVENESS SUMMARY
March 1995
U.S. Environmental Protection Agency
Region 10
-------
TABLE OF CONTENTS
1.0 OVERVIEW 1-1
1.1 SITE BACKGROUND 1-1
1.2 PROPOSED PLAN FOR CLEANUP 1-2
1.3 SELECTED REMEDY 1-3
1.4 SUMMARY OF COMMUNITY INVOLVEMENT AND CONCERNS 1-3
2.0 PUBLIC COMMENTS AND EPA RESPONSES 2-1
2.1 SOIL TREATMENT 2-1
2.2 ON-SITE CONTAINMENT FACILITY (OCF) 2-5
2.3 CAPPING 2-11
2.4 SHORELINE 2-13
2.5 SURFACE WATER 2-16
2.6 GROUNDWATER 2-18
2.7 OFF-SITE DISPOSAL 2-19
2.8 MONITORING/LONG-TERM CONTROLS 2-19
2.9 HEALTH 2-20
2.10 DEVELOPMENT/LAND USE 2-22
2.11 COSTS 2-24
2.12 PUBLIC INVOLVEMENT 2-25
2.13 MISCELLANEOUS 2-27
3.0 ASARCO'S COMMENTS AND EPA RESPONSES 3-1
-------
LIST OF ACRONYMS USED IN THIS DOCUMENT
AIP
ANS
ARARs
Asarco Site
CERCLA
CHB
DNR
EPA
MWEP
NPL
OCF
Park District
ppm
PRP
Puyallup Tribe
RCRA
ROD
Ruston
SARA
Tacoma
TCLP
WDFW
Agreement in Principle
American Nuclear Society
Applicable or Relevant and Appropriate Requirements
The Former Asarco Smelter Site
Comprehensive Environmental Response, Compensation, and
Liability Act of 1980
Citizens for a Healthy Bay
Washington State Department of Natural Resources
U.S. Environmental Protection Agency
Municipal Waste Extraction Procedure
National Priorities List
On-Stte Containment Facility
The Metropolitan Park District
parts per million
Potentially Responsible Party
The Puyallup Tribe of Indians
Resource Conservation and Recovery Act
Record of Decision
Town of Ruston
Superfund Amendments and Reauthorization Act of 1986
City of Tacoma
Toxicity Characteristic Leaching Procedure
Washington Department of Fish and Wildlife
-------
1.0 OVERVIEW
The U.S. Environmental Protection Agency (EPA) has written this Responsiveness Summary to
respond to public comments received regarding the Proposed Plan for cleanup of the former
Asarco Smelter Site. EPA initially held a public comment period from August 12 through October
11, 1994. At the request of members of the community, the comment period was extended to
November 10,1994. This document reflects all of the comments that were either voiced at one
of the two public meetings held during the comment period, or submitted in writing. Questions
that were asked and answered at the public meetings, held on August 30 and September 19,
1994, are recorded in the meeting transcripts, and are not included in this document. The
transcripts are available in the Administrative Record for the Site is located at EPA Region 10, the
Main Branch of the Tacoma Public Library and all of the Information Repositories listed in Table
B-1 in Appendix B.
In addition to EPA's efforts, Asarco solicited public comments on EPA's Proposed Cleanup Plan
as well as on an "Agreement in Principle" between the company and local governments for future
development of the site. Comments received by Asarco in response to its request have been
summarized and are included with Asarco's comments on the Proposed Plan, Section 3.0 of this
document. The Responsiveness Summary meets the requirements of the Comprehensive
Environmental Response, Compensation and Liability Act (CERCLA) of 1980 as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA).
1.1 SITE BACKGROUND
The former Asarco Smelter project is part of the Commencement Bay Nearshore/Tideflats
Superfund Site in Tacoma, Washington. The Commencement Bay Site was placed on the
National Priorities List (NPL) in September 1983. The Asarco Smelter Facility and the adjacent
Tacoma Yacht Club breakwater (slag peninsula) are located along the shoreline in Tacoma and
Ruston, Washington.
The former Asarco Smelter Site (the Asarco Site) consists of the 67-acre smelter property and
the 23-acre adjacent peninsula. Many of the facility buildings and structures were erected on
slag fill (a black, rock-like byproduct from the smelting process), which extended the existing
shoreline when molten slag material was poured into Commencement Bay during smelting
operations. An estimated 15 million tons of slag exist on the smelter property and along the slag
peninsula.
Metal smelting and refining operations were active at the Asarco Site from the late 1800s until
1985 when the smelter facility was closed. During that time, lead and copper were refined from
metal-bearing ores and by-products of the smelting operations were further refined to produce
other marketable products such as arsenic, sulfuric acid and sulfur dioxide. Metals and organic
compounds were released into the air, soil, and Commencement Bay as a result of these
operations. Metals in the slag, or that were released into the soil have migrated into the Bay and
into groundwater underneath the Asarco Site.
Over the past several years, samples of soil, slag, surface, and groundwater have been taken at
the Asarco Site. Elevated concentrations of heavy metals and some organic compounds were
detected in soil and slag throughout the property as well as in the Bay, groundwater and
off-shore sediments. The contaminants of most concern for possible effects to public health and
1-1
-------
the environment include: arsenic, cadmium, chromium, copper, lead, nickel, silver, zinc, and
dimethylaniline.
Samples show that the principal threat to human health and the environment is the contaminated
material in the "source areas." EPA and Asarco have identified the following six source areas:
the Stack Hill, Copper Refinery Area, Cooling Pond, Arsenic Kitchen, Fine Ore Bins Building, and
the Southeast Area of the Plant. These are areas that have the highest known concentrations
of metals and/or organic compounds and continue to act as the primary known sources of
contamination to the Bay and groundwater. Elevated arsenic concentrations ranging up to
403,100 parts per million (ppm) were detected in soil samples at one source area at the Asarco
Site. Highly mobile organic compounds are also considered a principal threat because they are
leaching out into surface and groundwater that is flowing into Commencement Bay.
Cleanup actions are necessary at the Asarco Site because it currently poses long-term cancer
risks for workers, possible future visitors or residents, seaiife, and animals. EPA has selected a
comprehensive cleanup strategy in order to address the multiple sources of contamination at the
smelter property and along the slag peninsula. EPA identified a range of alternatives (series of
choices) to achieve cleanup objectives and goals for the Asarco Site. These alternatives are
summarized in Table 7-1 of the Record of Decision. EPA has evaluated the choices and public
comments on the Proposed Plan, and has selected the Phase I (source control) cleanup remedy
for the Asarco Site. In addition to evaluating cleanup options, representatives of Asarco, the City
of Tacoma (Tacoma), the Town of Ruston (Ruston), and the Metropolitan Park District (the Park
District) have formed a "land use committee" which has negotiated an "Agreement in Principle"
that calls for preparation of a consensual Master Use Plan for future development of the Asarco
Site after cleanup.
1.2 PROPOSED PLAN FOR CLEANUP
One of EPA's objectives in issuing the Proposed Plan is to enable the public to participate in the
process for selection of a cleanup approach for the Asarco Site. Public comments are solicited
to determine whether the range of approaches is adequate, whether the discussion of differences
between approaches is reasonable and comprehensive, whether EPA has made good choices
in developing a preferred alternative, and whether the choices made will meet community
objectives for the Asarco Site.
in developing the Proposed Plan, EPA considered the following nine legally mandated Superfund
evaluation criteria:
(1) Overall protection of human health and the environment;
(2) Compliance with federal and state environmental standards;
(3) Long-term effectiveness and permanence;
(4) Reduction of toxicity mobility, or volume through treatment;
(5) Short-term effectiveness;
(6) Implementability;
(7) Cost;
(8) State acceptance; and
(9) Community acceptance.
The Preferred Alternative, outlined in EPA's Proposed Plan, addressed contamination of plant site
soils, the slag peninsula, groundwater, and surface water. It was based on the alternatives
1-2
-------
summarized in Table 7-1 in the Record of Decision, plus additional elements that EPA believes
were necessary for a comprehensive cleanup. The individual components of the Preferred
Alternative included excavation and treatment of soils from the source areas; disposal of soil and
other materials; capping the entire Asarco Site; demolition of the remaining buildings;
replacement of the entire surface water drainage system; shoreline armoring of the plant site and
slag peninsula; abandonment of the production well; monitoring of surface and groundwater and
sampling of marine sediments; safety measures; integration of cleanup with land use plans;
cleanup schedule; and costs.
1.3 SELECTED REMEDY
EPA has carefully evaluated all of the cleanup alternatives and public comments received on the
Proposed Plan, and has selected a cleanup remedy to control the source of contamination at the
Asarco Site. This selected remedy is Phase I of the comprehensive cleanup plan, and is
described in detail in Section 9.0 of the Record of Decision. In general, the selected remedy for
source control of the contamination at the Asarco Site includes excavation of source area soils,
demolition of the remaining buildings and structures, disposal of the source area soils and
demolition debris in an on-site containment facility (OCF) which meets or exceeds regulatory
standards for hazardous waste landfills, cap the entire Site except for the OCF which has its own
cover, replace the entire surface water drainage system, armor portions of the plant site and slag
peninsula shoreline, continue to monitor tine surface water and groundwater, sample marine
sediments and develop and implement an enforceable program of restrictions and guidelines to
supplement the actual cleanup activities to ensure that the remedial action remains protective.
1.4 SUMMARY OF COMMUNITY INVOLVEMENT AND CONCERNS
EPA has placed a high priority on community involvement because many Ruston and North
Tacoma property owners and residents may be affected by EPA's chosen cleanup approach.
EPA recognizes that, in addition to cleaning up contamination at the Asarco Site, the community
is very interested in the future use of this property. Although the primary mission of the EPA is
to design a cleanup that protects human health and the environment, EPA believes that this can
be accomplished with future development of the Asarco Site in mind. To achieve this goal,
significant citizen participation has been important to EPA's process for selecting a remedy. The
following activities were undertaken by EPA to seek public input:
• Availability Sessions where citizens could visit one-on-one with EPA and Asarco
to discuss cleanup plans,
• Meetings with interested small groups to discuss investigation findings and
cleanup alternatives;
• Interviews with individual citizens to improve understanding of community
concerns;
• A 90-day public comment period to provide citizens with an opportunity to review
the Proposed Plan and other documents related to the cleanup and submit
comments to EPA;
Two public meetings, held on August 30 and September 19, 1994, to answer
questions and obtain citizen input on EPA's Proposed Plan; and
1-3
-------
• Meetings with the Ruston/North Tacoma Coordinating Forum which is comprised
of representatives from local, state and federal municipalities or agencies.
Transcripts of the August 30 and September 19 public meetings and the public comment letters
and cards received by EPA are part of the Asarco Smelter Administrative Record, which is
available for viewing at EPA Region 10, the Main Branch of the Tacoma Public Library and all of
the information repositories listed in Table B-1 in Appendix B. In general, the commenters
expressed concerns about the soil, groundwater, and surface water contamination, and its health
effects; the longevity and stability of on-site containment/disposal; the effects on future land use;
and issues involving the cleanup plan design, costs, and benefits to the community from future
development.
The next six paragraphs provide a summary of comments received and are followed by a detailed
response section to specific comments. During the comment period, numerous commenters
expressed preferences regarding the cleanup of the contaminated soils. Some commented
specifically in relation to the future development of the Asarco Site. Many commenters stated
a preference for on-site containment of the contaminated soils, reasoning that only by approving
the less expensive OCF alternative would there be money left over to develop the Asarco Site.
Many stated a preference for on-site containment, reasoning that an OCF is safe, environmentally
effective, and the most economical alternative. Other commentors opposed on-site containment
because of concerns regarding the stability, longevity, and safety of an OCF, and stated that
development should not be an issue in choosing the best cleanup decision. Several commenters
felt that the development money Asarco has offered may have already tainted the cleanup
decisions of EPA and the local communities. Other commenters suggested that a combination
of on-site containment, treatment, and/or off-site disposal would be the most effective remedy for
the contaminated soils and other materials.
Contamination in the groundwater, surface waters, and sediments was a concern of some of the
commentors; they felt that EPA did not adequately address this issue in the Proposed Plan and
offered opinions and suggestions regarding the remediation of these areas.
Many commenters voiced their opinions or suggestions regarding the proposed treatment of soils
at the Asarco Site. Some commenters expressed a preference for on-site treatment prior to
disposal; others opposed on-site treatment because of issues regarding stability, post-cleanup
monitoring, and cost of treatment. Several commenters made suggestions of alternative treatment
methods for the contaminated soils.
Many commenters also voiced their opinions and offered suggestions regarding the nature of
future development at the Asarco Site. Some commenters expressed appreciation for the efforts
of Ruston, Tacoma, the Park District and Asarco in negotiating a Master Development Plan and
were eager to see development of the site. Other commenters disagreed, referring to the plan
as a "bribe" to the nearby residents of Ruston and Tacoma to influence their acceptance of a less
expensive OCF without treatment.
Some commenters expressed appreciation for past and current efforts on the part of EPA and
Asarco; others expressed criticism of one or both organizations. Several commenters indicated
disapproval of Asarco and what they viewed as action motivated only by organizational
self-interest, which was seen as running counter to public interest. Some commenters expressed
the opinion that Asarco had excessively endangered public health in its pursuit of profits.
1-4
-------
Asarco provided comments to EPA that are included in Section 3 of this Responsiveness
Summary. Additional public comments received by Asarco are also included in this section. The
next section (Section 2) provides detailed responses to public comments communicated verbally
during the public meetings, and written communications received by EPA during the 90-day
public comment period.
1-5
-------
2.0 PUBLIC COMMENTS AND EPA RESPONSES
2.1 SOIL TREATMENT
1. COMMENT: Several commentors recommended against treatment of contaminated soil.
Several commentors questioned the long-term effectiveness of the proposed soil
treatment. Some commentors stated that encapsulation/stabilization is an unproven
technology, is difficult to monitor over the long-term, does not reduce the volume of the
contaminants, and/or is not cost effective. Some commentors expressed the opinion that
there may be serious risks if the resulting mixture were spread over the Site, because the
small concrete particles may break down with an end result that is worse than the current
situation. Several commentors added that this would have a devastating impact on future
Site development. One commentor also stated that, due to the unknown long-term
effectiveness of stabilization, this option does not meet the nine evaluation criteria.
RESPONSE: Although EPA is not selecting soil stabilization/solidification for the Asarco
cleanup, it has been used at a number of Superfund sites around the country. These
technologies are relatively new, such that no data exists that would show how the
stabilized material would hold up 50 or 100 years from now. However, tests have been
developed to simulate conditions in the future.
EPA believes that many commentors expressed a valid concern about the future
monitoring of the treated soils if the soils were placed in various areas beneath a site cap.
Although EPA believes that an effective monitoring system could be designed to detect
if treated soils were contributing to groundwater contamination, it believes that the leak
detection and collection system for the OCF is better with respect to identifying any future
problems. Monitoring any Superfund remedy over the long-term always presents site
specific challenges and EPA believes that a successful monitoring program can be
developed for the Asarco cleanup.
2. COMMENT: A few commentors, including the City of Tacoma Environmental Commission
and Citizens for a Healthy Bay (CHB), expressed the opinion that long-term monitoring
of the Asarco Site after the cleanup activities were completed would be more difficult and
costly if the soil were treated because the treated material would be placed throughout
the Site. CHB also expressed the concern that deed restrictions would be necessary.
RESPONSE: In EPA's original proposal, treated soils would have been consolidated in
the excavated or other areas on the Site not impacted by groundwater, not spread
around. The groundwater monitoring program that EPA would have required for treated
soils would have been equivalent to that selected for the OCF.
Deed restrictions and institutional controls will be necessary regardless of the remedy
selected because some hazardous contaminants will remain on site under all of the
alternatives.
3. COMMENT: Several commentors stated a preference for on-site treatment of metals and
other contaminants of concern prior to disposal. One commentor cited off-site health
risks, Potentially Responsible Party (PRP) liability, and cost benefits as reasons for on-site
treatment.
2-1
-------
RESPONSE: EPA has selected disposal of excavated source area soils in an on-site
containment facility (OCR) without requiring soil treatment prior to disposal. As discussed
in section 7.2 in the Record Of Decision (ROD), EPA compared the potential movement
of contaminants out of the OCF of treated and untreated soil. EPA found that the
potential difference in leachate between treated and untreated soil disposed in an OCF
was minimal if the good quality of the cap and bottom liner was maintained.
EPA believes that disposing the source area soil in an OCF and capping the rest of the
Site will alleviate any potential health risks to adjacent neighborhoods. Asarco will be
responsible for the cleanup regardless of the remedy selected. Most of the public
comments received supported an OCF more than soil treatment because an OCF cost
less and would allow future development to occur. EPA believes that the additional cost
for soil treatment would not result in a more effective remedy over the long-term.
4. COMMENT: One commentor suggested that EPA perform a series of small pilot tests to
determine the effectiveness of the proposed treatment on the contaminated soil prior to
engaging in final cleanup activities.
RESPONSE: In May 1994, EPA, Asarco and Asarco's contractor HEX, conducted a pilot-
scale treatment project that solidified approximately 500 cubic yards of soil at the former
Asarco Smelter Site. The results are described in Appendix C of the ROD. Additional
information can be found in section 2.5 of the Administrative Record.
5. COMMENT: One commentor expressed concern that treating the soil with lime may
create a different mixture of contaminated elements, and wondered if the EPA has
conducted tests to ensure that this does not occur.
RESPONSE: The pilot-treatability study used lime, or calcium oxide, as one of the primary
additives. EPA found that "a different mixture of contaminated elements" was not created,
rather the metals were simply bound up within the cement. The results of this study can
be found in the Asarco Smelter Administrative Record and are described in Appendix C
of the Record of Decision (ROD).
6. COMMENT: Citizens for a Healthy Bay (CHB) does not support soil stabilization and
commented that there are no assurances that the treated soil will remain stable and will
not teach 10, 50, or 100 years from now. They stated that the long-term teachability of
the stabilized material is difficult to determine because the method used to evaluate the
long-term mobility, the Municipal Waste Extraction Procedure (MWEP), utilizes a 30-day
test, and the results of some of the teachability tests were not made available to the
public.
RESPONSE: MWEP and the Toxicity Characteristic Leaching Procedure (TCLP) are
reasonably good predictors of future leaching, but the treatment technology is so new
that actual results of how well treatment works over a long period of time are not
available. EPA believes that the MWEP and ANS 16.1 water leaching tests, which are
frequently used today at municipal waste facilities, are good predictors of the future
impacts of rainwater and surface water coming into contact with treated soils. A summary
of the results of both of these tests are attached in Appendix C and the complete
document is located in the Administrative Record for this Site.
2-2
-------
7. COMMENT: The Tacoma-Pierce County Health Department stated that it would only
support treatment if EPA could assure that treatment would be a "permanent fix that
would never leach."
RESPONSE: EPA cannot make this guarantee for either disposal option for contaminated
soils at the Site. The only alternative that may be able to meet this criterion is "off-site
disposal." However, off-site disposal is much more expensive than other available
options. Further, even with off-site disposal, it is not possible to remove all contaminated
material so some contaminated soil and slag would still remain on Site and need to be
capped. For more information on the reasons for this decision to select an OCF, see
Section 8.0 in the ROD.
Alternative Treatment Methods
8. COMMENT: Several commentors indicated that additional treatment technologies exist
to remove and/or destroy metals in the soil and that these technologies should be
considered in the cleanup plan. Citizens for a Healthy Bay (CHB) requested that the time
to consider different cleanup options at the Site be extended to assess the results of
alternative treatment studies and allow for public review. CHB also requested that copies
of all information received by EPA regarding treatment technologies be sent to their office
for review and publication. Two commentors stated that the public comment period
should be reopened when the results of any treatment technology are received by EPA.
RESPONSE: Under an EPA Administrative Order on Consent, Asarco conducted a
literature search for treatment technologies which would eliminate metal contamination
from soils at the former smelter site (see the 'Treatability Literature Study Report," May 12,
1992 in Section 2.5.5 of the Administrative Record). Through this literature search it
appeared that soil stabilization/solidification was the most appropriate treatment
technology for the contamination at this Site. During the public comment period, another
treatment vendor claimed that his company's soil-washing technology could remove the
metals from the soils for approximately the same cost as on-site containment. EPA has
been working with this vendor since the first public meeting, but as yet, has not received
additional information which indicates that this treatment process is effective. EPA has
informed the vendor of its continued willingness to receive information. The additional
soil treatability information on the MWEP test was sent to Citizens for a Healthy Bay. EPA
did extend the public comment period for an additional 30 days.
9. COMMENT: Several commerrtors suggested that chemically extracting the metals from
some of the more contaminated soils would be an environmentally and economically
sound alternative to stabilization and/or land disposal.
RESPONSE: To date EPA has not identified a chemical-extraction process which is
effective for the metals which are found on Site.
10. COMMENT: Several commentors suggested a variety of additional treatment
technologies for contaminated soils and/or groundwater. Some of the soil technologies
recommended are: (1) bioremediation, (2) combining the metal-contaminated soil with
excavated clay and melting the mixture in an on-site kiln, (3) "closed incineration" which
is used by oil companies, and (4) the use of any in-situ technologies where possible. In
2-3
-------
addition, a commentor suggested using wet oxidation of organics, electro-filtration of
heavy metals and ozone treatment for groundwater.
RESPONSE: EPA required Asarco to conduct a treatability literature search report, see
reference in Response No. 8. In this report all of the applicable technologies for
treatment of metals contamination in soils were evaluated.
(1) Bioremediation. EPA believes that the commentor is referring to the bioremediation
of metals in an artificial wetland environment. If this is the case, there are microbes that
can be used to alter the oxidation state of metals, which in some cases may result in the
metals becoming less mobile, but this process would not remove the metals from the
environment. Biological treatment of leachate that is generated at some sites has also
been used, but this type of treatment does not favorably impact the source of the
contamination. Conceptually, Desulfouibrio spp. (a type of microbe) can cause metals
to be precipitated in sulfides, but this type of treatment has not been shown to be
effective on the type or concentrations of waste at the smelter site.
(2) In-situ vitrification of metals in soil, or combining clay with contaminated soils at high
temperatures, was explored, but determined not to be cost-effective. One company,
Geosafe, has conducted field demonstrations (small scale) of soil vitrification, which would
bake the soil into a slag-like matrix. This has not been proved to be effective at full-scale
yet.
(3) Closed Incineration. EPA spoke to the project manager of "Seaview" (Bluebell,
Pennsylvania) who developed the technology for "incinerating" hazardous compounds,
primarily hydrocarbons, found in off-shore drilling materials. This process involves heating
the contaminated materials until the hydrocarbons are burned out of the sediments. EPA
does not believe that this treatment process would be effective for treating the
contaminated soils found at the Asarco Site.
(4) In-situ technologies, such as soil flushing or vitrification could potentially be used at
the Site. However, environmentally dangerous chemicals (e.g., strong acids and chelating
agents) would have to be used for soil flushing and it would be necessary to be
absolutely sure that all of these chemicals could be captured before they discharged into
the bay. Additionally, this could be a lengthy and expensive process due to the high
metal concentrations found at this Site.
Following completion of the actions under this ROD, EPA will evaluate the need for
remedial measures for surface and groundwater. If surface water treatment is necessary,
Asarco will be required to evaluate these approaches, along with others. In-situ treatment
technologies will be considered where appropriate.
11. COMMENT: One commentor suggested using sulfur instead of lime in the proposed
treatment, because the higher pH of lime would increase the solubility of arsenic.
RESPONSE: EPA recognizes that sulfur chemicals are another set of treatment reagents
that could be used to produce insoluble species of arsenic. Like the cement and lime
based solidification methods, sulfur reagents have to be tested to make sure they are
compatible with the particular waste that is being treated. The concerns that EPA has
with sulfur chemicals are (1) the treated soil would be "soil-like" which would mean that
2-4
-------
surface/groundwater would be more likely to come into contact with the treated soil
particles and (2) although sulfides are stable in a low oxidation environment, if they are
exposed to air, the sulfides can oxidize and release a more soluble form of arsenic and
sulfate.
2.2 ON-SITE CONTAINMENT FACILITY (OCF)
12. COMMENT: Numerous commentors expressed their support of the Master Development
Plan and stated a preference for on-site containment without treatment. A majority of the
commentors reasoned that only by approving the less expensive alternative would there
be money available to invest in development of the Asarco Site. In addition, some people
expressed the opinion that, besides saving money, on-site containment without treatment
would save time. Other commentors reasoned that, as the soil treatment and OCF
options are equally protective, the additional dollars that would be required for treatment
are better spent on preparing the land for development. One person added that an OCF
can always be dug up later if it is determined to be a hazard.
RESPONSE: EPA is required to select a remedy which is protective of human health and
the environment. Both soil treatment and on-site containment are protective cleanup
options. In this case, EPA further considered the compatibility of protective cleanup plans
with future land use plans. EPA believes that the future use of this Site is important and
has tried to select cleanup activities that will not prevent reasonable future uses of the
Site. EPA has also considered the cost effectiveness of the alternatives. However, it
should be noted that EPA's determination that the selected remedy is cost-effective is
based on a comparison of the various cleanup approaches described in the Proposed
Plan, not on Asarco's ability to afford land development activities.
Contrary to the commentors belief, soil treatment would be completed faster than
designing and constructing an OCF. The pilot-treatability test indicated that the soil
treatment would take approximately 6 months. However excavating and disposing soils
in an OCF could take approximately 2 years.
It is true that an OCF could be "dug up" in the future if it is determined that the OCF is
not as effective as once thought and/or if a new treatment technology is discovered.
However, EPA believes that the likelihood of this happening is small. EPA is selecting a
hazardous waste facility (the OCF) as part of its cleanup option because it believes that
this unit can be constructed in a manner which will effectively isolate the waste from the
environment and be protective of human health and the environment over the long-term.
13. COMMENT: Several commentors questioned the integrity and effectiveness of on-site
disposal, stating that OCF technology is still new and unproven and other waste disposal
sites, over time, have all experienced leakage. Two people cited the example of Gas
Works Park in Seattle, where the public was assured the soil was safe, but the soil was
later discovered to be unsafe and had to be removed at great expense to the taxpayer.
Another commentor referred to an example several years ago when Tacoma encouraged
the development of apartments near its refuse site. The contaminants eventually surfaced
and the public had to purchase the apartments at a high price following lawsuits.
Additionally, several commentors questioned the teachability of contaminants to
groundwater and surface waters from an OCF.
2-5
-------
RESPONSE: Many of the landfills which have failed in the past have been municipal solid
waste landfills that have not been constructed with multiple liners and caps which would
be required at the Asarco Site. These landfills have contained a variety of wastes (e.g.,
solids, liquids, and hazardous constituents). Over time, many of these incompatible
wastes have mingled creating either the release of toxic leachate or methane gas. The
OCF, which has been selected for this Site, will not contain different types of wastes,
rather it will contain "inert wastes" (wastes that are not chemically reactive with each
other) such as contaminated soil and demolition debris (excluding wood). Since the
metals in the source area soils have been found to become mobile when water passes
through them, it will be important to design a cap which strictly controls surface and
groundwater infiltration.
14. COMMENT: Several commentors raised questions regarding the stability of an OCF or
landfill in what they considered to be the probable event of a major earthquake. One of
these commentors expressed the belief that, due to the geology of the area, an
earthquake-triggered (or other naturally-occurring) slide would carry contaminated
materials into the bay. One commentor wondered if the Site was fundamentally suited
for an OCF.
RESPONSE: Preliminary seismic evaluations of the smelter plant area were conducted
during the Feasibility Study. These evaluations indicate that this area is suitable for an
OCF (e.g., it is not located on a fault line). However, an additional seismic evaluation of
the area where the OCF will be constructed will be a requirement of the Remedial
Design/Remedial Action work plans that are developed after the ROD is signed.
15. COMMENT: Several commentors expressed the opinion that if the OCF alternative is
chosen a multiple ceil approach should be used, with the more contaminated soils stored
and/or treated and disposed in a separate cell. They reasoned that this approach would
allow for one more level of protection for a leaking OCF and enable removal of the
contaminated soils in the future if necessary. Another commentor added that separate
cells would offer more precise monitoring capabilities, because the contaminated material
ranges over three orders of magnitude in contaminant concentration. Another commentor
suggested that, by using separate cells, the more contaminated soils could be treated
when new technologies become available.
RESPONSE: Because the type of material to be placed in the OCF is relatively similar
(metal contaminated soil and debris) EPA does not believe that there are significant
advantages to storing the waste in separate cells. Segregating soils based on the metals
concentration may be appropriate if there were a promising soil treatment technology
pending and EPA believed that certain soils would be a good candidate for treatment.
However, this is currently not the case.
The reasons that landfills are normally separated into multiple cells is to (1) separate
incompatible wastes and the leachate from those wastes and (2) to limit the open portion
of a large landfill that will operate over many years so as to limit the area available for
collection of precipitation. Under this scenario, each cell would be constructed and
covered prior to constructing another cell. Neither of these reasons are relevant to the
Asarco OCF as the waste to be placed is not incompatible and the duration the OCF will
be open is short.
2-6
-------
16. COMMENT: One commentor stated that EPA did not present soil treatment before
disposal in an OOP as an option in the Proposed Plan, and that treating the most
contaminated soils may be a way to mitigate the high costs of remediation and still allow
for future development.
RESPONSE: EPA presented this alternative, soil treatment before disposal in an OCF,
in Section (H)(7) of the Proposed Plan. The estimated cost of this alternative was $65.5
million. When the Proposed Plan was issued, EPA did not believe that it would be
necessary to dispose treated soil in a hazardous waste landfill. Therefore, the costs of
disposing treated soils were calculated based on a solid waste landfill. This cost was
$70.2 million because hazardous demolition debris would still need to be properly
disposed off-site. Disposing treated soil and debris would be more expensive than using
an OCF.
17. COMMENT: Two commentors expressed concern that tourists, families, developers,
and/or restaurateurs would be hesitant to visit or build on a hazardous waste site that
may potentially leak.
RESPONSE: The hazardous waste to be disposed in the OCF would be isolated from
potential access by people through a multilayer cover and the legal restrictions requiring
that the cover be maintained. Further, as part of the future land use activities sponsored
by Asarco, Tacoma, Ruston and the Metropolitan Park District, interviews were conducted
with bankers and future developers to determine if there would be a market for
development on a remediated Superfund site. The research indicates that constructing
an on-site landfill does not appear to pose significant barriers to future uses of and
investment in the Site.
18. COMMENT: One commentor stated that the option of including both soil and demolition
debris in an OCF should have been presented in EPA's evaluation of cleanup options.
RESPONSE: This option was included in EPA's Preferred Alternative, on page 14 in
Section (G)(1)(b) and (c).
19. COMMENT: One commentor suggested that the "ditch" leading up to the railroad tunnel
would be an ideal location for the OCF, because it is unattractive and in need of
remediation.
RESPONSE: EPA does not believe that this would be an "ideal" location because the
gully located on the south side of the stack hill is private property and may potentially be
considered a wetland. In addition, there are many areas along the hillsides where
groundwater exits and creates small ponds and marshes at the base of the gully. It is
important to select an area for disposal of contaminated materials where surface water
and groundwater can be controlled.
20. COMMENT: One commentor inferred that, because Hydrometrics (the contractor hired
by Asarco to design the OCF in the Feasibility Study) is a subsidiary of Asarco, their
assurances regarding the safety and stability of an OCF cannot be taken seriously.
RESPONSE: EPA expects Hydrometrics to perform all of its work in accordance with
appropriate professional standards regardless of who owns the company. In addition,
2-7
-------
EPA and its own consultant, IGF/Kaiser Engineers, Inc., have carefully reviewed
Hydrometrics' work to ensure that Hydrometrics' data-gathering, analyses, findings, and
conclusions, including with respect to the construction of an OCF, have been performed
in accordance with acceptable methods and legal requirements. Further, EPA's in-house
technical personnel have conducted their own independent analysis of an OCF and have
concluded that it can be constructed in a manner that is protective of human health and
the environment.
21. COMMENT: One commentor requested that EPA provide an example of an OCF that has
been around for 50 years in a geographically similar area and exposed to an equivalent
amount of water runoff. He also added the question: If the soil is so stable, why then
is there contamination in the surface water?
RESPONSE: Because there were no requirements for double-lined landfills with separate
leachate detection and collection systems before 1984, specific examples of the
performance of double-lined landfills more than 10 years old are not available.
The contamination that is found in the surface water is primarily from soil particles being
carried by the water (total metals) and not from metals leaching off soil particles into the
water (dissolved metals).
22. COMMENT: One representative from the Washington and North Idaho District Council
of Labor expressed opposition to on-site containment because of the poor labor
relationship that his union is currently experiencing with Hydrometrics or Asarco.
RESPONSE: EPA has no authority to mediate labor disputes between Asarco and its
contractors. EPA requires, however, that Asarco comply with worker health and safety
requirements at all times during performance of cleanup work.
23. COMMENT: One commentor supported the use of pre-stressed concrete in the
construction of an OCF.
RESPONSE: Although concrete liners and caps could be constructed to prevent
contaminants from migrating out of the OCF or prevent water from migrating into the
OCF, concrete has a higher tendency to fracture. If this occurred in the liner, it would be
irreparable, whereas clay has the capability to reseat itself if water were to contact it in the
future. Experience has demonstrated that concrete, or asphalt caps, generally require
more maintenance than clay and synthetic caps.
24. COMMENT: One commentor stated that concentrating contaminated residential soils in
an OCF close to the shoreline would further aggravate the local environment.
RESPONSE: Residential soils will not be disposed in an OCF, but will be used as a sub-
base to the low permeability cap (see Figure 7-1 in the ROD) that will be placed on the
Site.
25. COMMENT: One commentor asked if releases from an OCF could be monitored if the
Site is already contaminated and wondered if existing contamination would make it more
difficult or unlikely to detect leaks from an OCF.
2-8
-------
RESPONSE: EPA has many years of groundwater data from this Site that can serve as
a baseline prior to construction of the OCF. EPA plans to continue groundwater
monitoring before, during and after cleanup. Therefore, we will be able to evaluate the
groundwater contamination trends before and after construction of the OCF. In the event
that contaminants begin to leach out of the OCF, they will be detected as increases
above then existing conditions via the groundwater monitoring program.
26. COMMENT: One commentor stated that a hazardous waste facility, under Resource
Conservation and Recovery Act (RCRA) siting requirements, would not typically be
located in a wet climate with full public access and immediately adjacent to an
exceptional water body, such as Commencement Bay. For these reasons, if soil
treatment is ineffective, the proposed OCF should be modified to use additional clean, soil
as a cover to diminish future exposure, with the contaminated soils segregated by level
of contamination into separate cells. This commentor added that the OCF should be built
like any other RCRA facility, with the soils receiving the same amount of treatment as
would be required if they were to go to the RCRA facility in Arlington, Oregon.
RESPONSE: EPA agrees that a new hazardous waste landfill typically would not be sited
in this type of location, assuming that the area was relatively clean. EPA and the State
try to avoid introducing contaminants to pristine or clean areas. But the smelter site is
not such an area and it is generally recognized that a significant amount of
contamination, such as 15 million tons of slag, cannot be removed from this location.
Accordingly, EPA believes that construction of a landfill in accordance with federal and
state requirements at this location, given existing contaminated conditions, is an
acceptable part of the overall cleanup. EPA is not requiring treatment of soil prior to
disposal in the OCF because the OCF can effectively isolate the soil from the
environment, see Section 9.9 of the ROD. See Response to Comment No. 15 regarding
construction of separate cells.
27. COMMENT: One commentor stated that the siting decision for the OCF needs to
carefully consider the hydrogeology of the Asarco Site. An impermeable structure, such
as an OCF, is likely to alter the current groundwater system and raise the water table
around the OCF. He expressed the opinion that the OCF should not be constructed atop
a shallow aquifer if other more protective locations exist. Other commentors wondered
if there would be-any way to pump out water that may seep into the OCF before it moves
from the OCF into Commencement Bay.
RESPONSE: All groundwater and surface water which currently flows across or through
the central area of the Site, where the OCF will be located, will be rerouted through new
drainage systems or diversion trenches. It is not likely that the groundwater table will rise
as a result of these activities.
In addition, a thick silt aquitard lies beneath the shallow aquifer in this location and will
prevent rerouted or displaced groundwater from migrating to the deeper aquifer.
The OCF will be designed so that groundwater is unlikely to come into contact with the
OCF and so that surface water (rain water) will be diverted. In addition, EPA believes that
the minimal amount of leachate which may be generated inside the OCF will be handled
by the leachate collection and removal system before it is released into the groundwater
or the bay.
2-9
-------
28. COMMENT: A few commentors believe that EPA should consider the potential for
including contaminated sediments in the OCF. In contrast, the Town of Ruston
commented that it is opposed to using the OCF for the disposal of dredged, dewatered
marine sediments, due to the necessity of reopening a closed OCF, the potential for
adverse chemical reaction with materials in the OCF, and its adverse impact on future
development. Tacoma, the Metropolitan Park District and Asarco also opposed disposing
sediments in the OCF.
RESPONSE: At this time, it has not been determined that off-shore sediments need to
be dredged and disposed. However, Ruston, Tacoma, the Metropolitan Park District and
Asarco have presented several reasons why this material should not be disposed in the
OCF should dredging and disposal be required in the future: (1) the sediments will be
very wet and may introduce water into the OCF that could mobilize the metals on the
soils, and (2) there may not be enough room remaining in the OCF after the soils and
demolition debris are disposed. Although sediments could be dried before they are
disposed, it is unlikely that sufficient capacity could be added for the sediments without
interfering with land use plans. For these reasons, EPA agrees with the commentors
opposed to disposing sediments in the OCF. Other alternatives for disposing dredged
sediments will be evaluated by Asarco and EPA.
29. COMMENT: One commentor stated that because the Tacoma Asarco Smelter processed
ores that other smelters did not want, all of the contaminated soils should be
consolidated on the site.
RESPONSE: EPA agrees that consolidation of soils on site makes sense but not
necessarily for the reason provided by the commentor.
30. COMMENT: The Puyallup Tribe of Indians (the Puyailup Tribe) is concerned that the
construction of an OCF before implementation of a source control strategy may preempt
the future remediation of groundwater, therefore they request the construction of the OCF
not occur until after the groundwater studies are completed. The Tribe stated that a
source control strategy must develop specific plans for control of permitted and
unpermitted point source and non-point source discharges and that "No remediation
should beoin unless source control can be implemented and enforced." The Tribe added
that the cleanup of this Site must ensure that there will be no further pollutants entering
the environment from any source.
RESPONSE: The Tribe appears to be stating that EPA should directly reduce levels of
contaminants in surface water and groundwater prior to removing contaminated soil and
constructing an OCF for disposal of such soil. The Tribe's concept of "source control"
appears to be to treat contaminated surface water and groundwater prior to discharge.
EPA agrees with the Tribe's proposed result but not with its recommended sequence of
cleanup activities. Because contaminated soils existing at the Site are the primary source
of contaminants found in surface water and groundwater, EPA believes it is important to
first remove the most contaminated soils from the primary source areas and isolate them
from surface water and groundwater so the connection between the sources of
contamination and the discharges to Commencement Bay is severed.
2-10
-------
After the sources are removed and isolated in the OCF, the entire Site is capped, and a
new surface water drainage system is installed, EPA will monitor the levels of
contaminants in discharges from the Site. If these levels continue to exceed acceptable
requirements, EPA will determine what further actions, including water treatment, are
necessary to reduce the discharge of contaminants into Commencement Bay. EPA notes
that the cleanup levels for surface water are consistent with the Tribe's water quality
standards. By promulgating its water quality standards, the Tribe appears to recognize
that there are acceptable levels for pollutant discharges other than "no further pollutants."
2.3 CAPPING
31. COMMENT: One commentor preferred that Asarco cap the land "as is" rather than
excavating and consolidating the contaminated soils.
RESPONSE: The soils located in areas identified by EPA as "source areas" have very
high concentrations of contaminants which are mobilized by contact with groundwater.
In order to address the significant groundwater problem at the Site, EPA believes it is
necessary to remove these soils before capping the entire Site.
32. COMMENT: There were several comments regarding the capping materials that were
proposed to be used for a Site cap. Two commentors believe that the "clean" soils from
Pt. Defiance are probably also contaminated with Asarco emissions; another commentor
was concerned about contaminants from the excavated Study Area soils potentially
leaching into the Bay and another commentor suggested that contaminated sediments
as well as Study Area soils should be included in the cap.
RESPONSE: All soils used for the top layers of the cap will be sampled to verify that they
are clean. Although the Ruston/North Tacoma soils do not leach metals into surface
water or groundwater, EPA believes that the cap will protect the contaminated soil
particles from being washed into the bay by surface water. At this time, EPA is not sure
whether sediments will need to be dredged or not.
33. COMMENT: Several commentors expressed the opinion that the capping or OCF soil
cover should be greater than 2 feet so more substantial vegetation can be planted on top
without breaching the cap. One commentor added the opinion that a 1-2 foot soil cap
would not be sufficient to ensure permanent protection of construction, public access,
utility work, and other activities that may occur on site.
RESPONSE: The total thickness of a multilayer soil cap is at least two and a half feet;
for an OCF the thickness is at least five feet. The 1-2 foot soil cap required for the OCF
would be in addition to filter material, one foot of drainage material, a fabric liner and two
feet of compacted clay. For the soils cap, the one foot of clean soil would be in addition
to 6 inches of gravel and one foot of clay. EPA notes that plans for development of the
Site may result in even thicker layers of soil in the cap or above the cover of the OCF.
34. COMMENT: Two commentors stated that clay capping is susceptible to cracking. One
of these commentors suggested using a geomembrane liner in combination with the low
permeability soils as a substitute for clay capping. A few commentors are concerned
about suffide formation if anything other than a "soil only" cap is used or if waste is buried
deeper than four feet (sulfides increase the possibility of a "reducing" environment).
2-11
-------
RESPONSE: Although clays that dry out are susceptible to cracking, the advantage of
clay is that once surface water does begin to migrate through the cracks it rehydrates the
clay and the cracks are reseated. Although synthetic liners are often used in conjunction
with clay, it is for this reason that synthetics are rarely used alone. A synthetic liner may
be used as part of the cap and liner of the OCF and will not be used as part of the site
wide cap.
EPA has not experienced sulfide formation at sites where wastes were buried deeper than
four feet. Also, see Response to Comment No. 11.
35. COMMENT: The Tacoma-Pierce County Health Department's comment letter expressed
the opinion that the placement of contaminated residential soils under a cap containing
one foot of low permeability soils is not appropriate because the soil would be considered
dangerous waste if generated elsewhere in the state. It stated that the original plan was
for the residential soils to be disposed at an off-site landfill and asks how this fits into the
proposal to use soils as fill material on the Asarco Site. The Town of Ruston supported
using Ruston/North Tacoma soils as a sub-base for a cap on the Site.
RESPONSE: The Health Department later clarified its comment to EPA's project manager
and stated that their primary concern about the Ruston/North Tacoma residential soils
was their potential to leach. After EPA explained that the data indicated that these soils
do not significantly leach above regulatory standards with acid or water extraction, the
health department representative agreed that the proposed method of disposal was
sufficient.
The Ruston/North Tacoma Study Area Record Of Decision (June, 1993) stated that the
residential soils would be disposed off site unless an alternative method of disposal was
selected in the ROD for smelter cleanup. To determine whether it would be acceptable
to the community, EPA proposed using these soils as a sub-base for a cap in the
Proposed Plan for the smelter cleanup.
36. COMMENT: One commentor suggested that the contaminated Ruston/North Tacoma
soils should not be placed under future parks, open space, or in areas such as streams
crossing the Site.
RESPONSE: Since these soils will be beneath a protective cap, EPA believes that these
types of restrictions for the placement of residential soils are not necessary. In the event
that trees or vegetation that have deeper roots will be planted in parks or open spaces,
the thickness of the soil covering can be modified appropriately. Presently, EPA is not
aware of any streams crossing the Site.
37. COMMENT: One person was concerned that capping soils in place may still allow
contaminants to leach into groundwater aquifers and the bay. He stated that the soil
should be removed if the concentrations are dangerous.
RESPONSE: The most highly contaminated soils will be excavated. The Site soils which
will not be excavated do not appear to be primary sources of groundwater contamination.
However, because rainwater does contact these soils, soil particles are washed into the
bay. EPA believes that a clean soil and clay cap will prevent rainwater from coming into
2-12
-------
contact with the contaminated soils and will prevent contaminated soil particles from
washing into the bay.
38. COMMENT: A commentor stated that the cap should be designed to accommodate
underground parking.
RESPONSE: EPA's paramount interest is maintaining the integrity of the cap. If an
underground parking lot can be constructed so as not to compromise the integrity of the
cap, EPA will consider it along with other land uses that may be proposed.
2.4 SHOREUNE
39. COMMENT: One person commented that the entire slag face should be securely
enclosed so that no leaks are possible.
RESPONSE: If a non-permeable (leak proof) barrier of some type is placed securely
against the slag face a "bathtub" effect will be created on the Site. Right now, hundreds
of gallons of groundwater move through the Site each day. Placing a barrier at the slag
face would cause this water to back up. EPA believes that the shoreline armoring
approach will prevent erosion, but still allow groundwater to move into the bay.
40. COMMENT: The Washington Department of Natural Resources (DNR) expressed the
opinion that the alteration of the existing shoreline during Site cleanup, as described in
the Proposed Plan, may result in the exposure of new slag faces. They believe that this
may lead to additional contamination of the bay due to increased toxicity and mobility of
contaminants, as well as increase the volume of slag requiring treatment/disposal. DNR
cannot support any activities that would create freshly exposed slag and believes that this
issue has not been adequately evaluated in the nine criteria analysis. DNR recommended
that a quantitative analysis of leaching associated with freshly exposed slag be performed
prior to finalizing any plans to cut back the slag.
RESPONSE: EPA anticipates that at least some shoreline armoring will be necessary.
EPA shares DNR's concern about exposing too many freshly cut surfaces to bay water
since this is the condition when metals in the slag are most teachable. Prior to armoring,
EPA will determine if significant erosion is occurring. If it is, and armoring is necessary,
DNR, other Natural Resource Trustees, and interested members of the community will be
asked to be involved in the development of the remedial design work plans associated
with shoreline armoring.
41. COMMENT: DNR stated that armoring and careful design aimed at creating an area
which habitat would repopuiate is preferred without cutbacks which may lead to further
contamination of Commencement Bay.
RESPONSE: EPA agrees with this recommendation.
42. COMMENT: One commentor stated that implementability criteria, overall protection of
human health and the environment criteria, community acceptance criteria, and land use
plans have not included the analysis of shoreline armoring design.
2-13
-------
RESPONSE: Analysis of this alternative has been included in Section 8.0 in the ROD.
However, EPA agrees that additional studies will be necessary to determine the extent
and location of armoring and the specific design for anchoring the toe (bottom) of the
riprap.
43. COMMENT: Citizens for a Healthy Bay and other commentors stated that the Preferred
Alternative does not give an adequate description of the remediation proposed for the
shoreline. They suggested that before the ROD is written, more information regarding the
range of alternatives considered, the benefits and drawbacks of each alternative, and site-
specific information regarding how this or any other alternative would be implemented
needs to be made publicly available. They also questioned whether the riprap will be
placed on top of the existing slag face, or if the slag face will be cut away and then
covered with riprap as shown in the feasibility study.
RESPONSE: In the ROD, EPA has modified the Proposed Plan's approach with respect
to shoreline armoring based on public comments received. Before developing the design
for shoreline armoring, Asarco will be required to conduct additional studies to determine
where and to what extent the shoreline is eroding. Sections of the shoreline that are
significantly eroding will be armored. At that time, site-specific information will be
collected to determine whether cutbacks are necessary and how the riprap will be
anchored in order to design the armoring. Citizens for a Healthy Bay, the Natural
Resource trustees and other members of the public will be encouraged to participate in
this process. Also, see Responses to Comment Nos. 40 and 41.
44. COMMENT: The Puyallup Tribe agreed with the proposal for shoreline armoring. Another
commentor requested that the shoreline armoring requirements be flexible enough to
accommodate different shoreline needs.
RESPONSE: The shoreline armoring will be designed to accommodate future land uses.
Preservation and mitigation of shoreline habitat will also be an objective of shoreline
armoring.
45. COMMENT: One commentor stated that a minimum slope of 2.5 (horizontal) to 1
(vertical) needs to be used for any riprap placed on the slag face. It was further added
that the explanation was inadequate regarding how this alternative will be implemented
without interfering with future sediment remediation. He also stated that it is unclear as
to how the armoring will be held in place.
RESPONSE: EPA has been advised by the Corps of Engineers that in most locations,
the steepest slope that should be used for riprap armoring is 1 to 1.5, and that areas with
slopes greater than this would require cutbacks. Sequencing shoreline armoring and
sediment remediation activities will be necessary but at this time the extent of sediment
cleanup is not known. By the time work plans will be required for shoreline armoring
design, EPA should know what portion of the sediments are contaminated and how these
sediments can be cleaned up (e.g., capping, dredging or natural recovery). In many
places a "toe" can be excavated out of the slag in order to anchor the armoring. The
specific design details of armoring will be determined at a future date. EPA will
encourage members of the community to participate in this process.
2-14
-------
Natural Resources
46. COMMENT: Several commentors indicated that more emphasis should be placed on
developing a range of alternatives for restoration of the natural habitat of the bay,
nearshore, and shoreline areas. One commentor suggested that EPA establish an
ambitious whole-watershed restoration program as part of the site remediation plan; one
commentor stated that shoreline treatment and natural resource restoration options
should be explored before a final cleanup design is developed; and one commentor
requested that the effects of shoreline armoring on existing habitat be evaluated.
RESPONSE: EPA will work closely with community members and Natural Resource
Trustees to develop a comprehensive design plan to try to address all of the commentors
concerns. EPA will evaluate whether the mitigation/restoration sites identified by the U.S.
Army Corps of Engineers, EPA, U.S. Fish and Wildlife Service and National Oceanic and
Atmospheric Administration (NOAA) in the Commencement Bay Cumulative Impact Study,
Volumes I and II (May/June 1993) and the "Vision Document for Commencement Bay,"
by the Commencement Bay Cleanup Action Committee (November 19, 1993) are
appropriate for the Asarco cleanup.
Although EPA does not believe that "shoreline treatment" is possible, it will identify the
effects of armoring on the existing habitat and will explore mitigation opportunities while
designing shoreline armoring.
47. COMMENT: Several commentors suggested that the area be returned to a pre-industrial
wilderness.
RESPONSE: Although this is a nice idea, it does not appear to be practicable,
particularly given the 15 million tons of slag at the Site. EPA's objective is to cleanup the
Site so that it will not pose a threat to human health and the environment in the future.
48. COMMENT: Two commentors suggested that the EPA should coordinate its
design/cleanup efforts with resource agencies such as National Oceanic & Atmospheric
Administration and the Natural Resource Damage Assessment Trustees.
RESPONSE: EPA has been working with these agencies during the RI/FS and decision-
making phases and will continue to do so during remedial design and remedial action
activities.
49. COMMENT: One commentor expressed the opinion that the alternatives presented (OCF
or soil stabilization) are not adequate to accomplish the cleanup correctly. He believes
the cleanup should integrate public health issues with the restoration of both aquatic and
terrestrial habitats, and the economic thresholds necessary to facilitate quality
development.
RESPONSE: The cleanup activities which have been selected are intended to prevent or
minimize the contaminant exposure to humans, animals and sealife. Preservation of
habitat (or mitigation for adverse impacts to habitat) are also an objective of this cleanup.
EPA intends to continue working with the local community regarding the future
development of the Site so that "quality development" after the cleanup will also be
possible.
2-15
-------
50. COMMENT: The U.S. Fish and Wildlife Service commented that they were pleased to see
that EPA recognizes mitigation for habitat losses associated with remediation activities as
a necessary element in the overall success of the preferred alternative.
RESPONSE: EPA hopes that the U.S. and State Fish and Wildlife Services will continue
to be involved in this project.
51. COMMENT: One commentor stated that restoration should be considered while a
remediation plan is being developed and that EPA should consider restoring the two
natural streambeds that were on the Site. Two commentors requested that as the site
remediation plan is finalized, the OCF, liners, and other infrastructure should be made
consistent with the restoration of natural streambeds and areas near the shoreline. One
commentor suggested that water-sensitive site design that allows natural infiltration of
stormwater runoff and reestablishment of natural vegetation be adapted in the location
of the two former small streams on the Asarco Site.
RESPONSE: EPA recommends that stream bed restoration be considered under the
future development process. EPA notes that CERCLA § 107(f)(1) does not allow for
recovery where damages to natural resources have occurred wholly before December 11,
1980. "Natural infiltration" of stormwater runoff is not a good idea if it means that
stormwater will come in contact with contaminated soils beneath the Site cap.
Sediments
52. COMMENT: One commentor expressed the opinion that guidelines must be developed
for further maintenance and repair of the existing pier structures to minimize- impact to
sediments.
RESPONSE: EPA's selected cleanup remedy does not address the existing piers. If
these piers are to be used for future land use activities, the repair and maintenance will
need to be addressed by the Public Development Authority established to oversee future
development activities.
2.5 SURFACE WATER
53. COMMENT: One commentor advised that plugging the present drainage system should
be done in such a manner as to prevent all water from leaching into the pipes and
potentially draining into the bay, and that care should be taken to avoid incidental
flushing of the contaminated drain sediments into the bay. This commentor also stated
that if applicable and relevant and appropriate requirements (ARARs) are not reached
through these surface water measures, surface water treatment be required regardless
of its cost. He also wondered if any drainage system presently exists on the slag
peninsula. The Puyallup Tribe noted that treatment of surface water (and groundwater)
would be difficult particularly during peak flows. The design of the treatment system must
account for the worst case scenario instead of allowing for waivers of water quality
standards or by-passes.
RESPONSE: Under EPA's selected remedy, all of the existing surface water drainage
system will be plugged. If the surface water that flows through the new drainage system
does not meet the remedial action objectives (see Section 9.9), surface water treatment
2-16
-------
will be required to the maximum extent practicable. There is no drainage system on the
slag peninsula.
54. COMMENT: The Town of Ruston commented that any surface and stormwater
management and drainage systems must be designed in consultation with Ruston,
Tacoma, and the Park District and meet or exceed all local, state and, federal standards
and regulations. The Town of Ruston stated that the surface water drainage system
should not be designed as to make routine maintenance and/or any required repair
prohibitive.
RESPONSE: EPA will work with the Town of Ruston to accomplish these objectives by
involving the Town in development of the Statement of Work and work plans for the
design and implementation of the cleanup.
55. COMMENT: The Puyallup Tribe commented that the existing surface water drainage
system needs to be plugged and abandoned and a new system constructed. If surface
water quality fails to meet federal and state standards, treatment of surface water must
be required regardless of cost. The Tribe also requested the creation of detention
facilities, such as small streams and drainages, to provide natural areas for wildlife and
help control surface water during peak flows. In addition, it requested that Site cleanup
ensure that no additional contaminants be released into the environment (e.g.,
recontaminate the sediments). The Tribe objected to the use of a mixing zone.
RESPONSE: EPA agrees with the need to plug and abandon the existing surface water
system and build a new one (see Section 9.3 of the ROD). If surface water cleanup levels
are not attained as a result of the new system and capping the Site, the need for
treatment will be evaluated.
Detention facilities, silt fences, diversion ditches, cut and fill slopes, will be used as
appropriate when soil is being excavated in order to reduce contaminated runoff from
excavated areas. Once a soil cap is placed on the Site, EPA will evaluate whether such
measures are needed as part of the new surface water drainage system. See Response
to Comment No. 51 regarding streams on the Site. EPA believes that construction of a
surface water drainage system will prevent the release of contaminants into the bay from
surface water. EPA notes that mixing zones are authorized under both state law and
Section 9 of the Tribe's Water Quality Standards. Whether a mixing zone is appropriate
for the Asarco Site will be determined during remedial design.
56. COMMENT: One commentor stated that the former cooling pond area should be fully
remediated to become part of the overall natural area on the Asarco Site, and added that
the contaminated soil in the cooling pond area should not be capped in place but
removed.
RESPONSE: Approximately seven feet of contaminated soil will be removed from the
cooling pond area. If contaminated soil exists beneath this depth it will be capped.
Whether this area becomes a "natural area" or a "development zone" will be determined
with community participation during future land use meetings.
2-17
-------
2.6 GROUNDWATER
57. COMMENT: Several commentors stated that passive treatment of groundwater and
surface water is not adequate and that a source control strategy for point source and
non-point source discharges should be implemented prior to commencement of soil
remediation. One commentor added that the mass loading of hazardous releases from
groundwater and surface water should be fully documented, and a cleanup strategy
developed to ensure that contaminants will not continue to enter Commencement Bay.
Another commentor requested that the EPA provide more detail on how groundwater will
be remediated, and stated that groundwater remediation would result in a significant
reduction of ongoing injuries to the bay's natural resources. Two commentors stated that
if monitoring reveals that the groundwater fails to meet federal and state standards, the
Master Development Plan must allow for the construction and operation of a treatment
facility or other contingency plan. The Puyallup Tribe commented that the remediation
of soil may interfere with the future remediation of groundwater.
RESPONSE: Efforts to document and evaluate surface water and groundwater
contamination are presently underway with the collection of surface water data every
month and the collection of groundwater data twice a year. EPA believes that the source
control activities selected will significantly reduce contaminant loading into surface and
groundwater. See Response to Comment No. 30 regarding the sequencing of cleanup
activities and the basic premise of EPA's source control strategy.
If it is determined that active measures are necessary to clean up surface water and
groundwater, a separate analysis and proposal regarding such measures will be issued
for public review. EPA does not agree that soil remediation will interfere with the future
remediation of groundwater because removal and disposal of soil does not preclude
active measures for groundwater.
58. COMMENT: One commentor stated that the preferred alternative will fail to achieve
cleanup goals for groundwater because EPA's preferred alternative proposes a waiver of
applicable or relevant and appropriate requirements (ARARs) relating to groundwater
cleanup and deferral of sediment remediation.
RESPONSE: At this time it is not certain whether source control activities selected by
EPA will attain the federal and state groundwater cleanup goals. Accordingly, a
temporary waiver of the requirement to meet such goals for this action is appropriate.
EPA will continue to monitor the Site and will take the appropriate groundwater cleanup
measures if necessary and to the maximum extent practicable.
59. COMMENT: One commentor recommended continual groundwater monitoring at the Site
until it is determined that contamination no longer exists.
RESPONSE: EPA and Asarco agreed to a long-term groundwater monitoring plan in
October 1994 that requires groundwater monitoring until 1999. EPA anticipates that a
cleanup decision for the groundwater will be made by then.
2-18
-------
2.7 OFF-SITE DISPOSAL
60. COMMENT: Several commentors expressed a preference for the removal of
contaminated soil and off-site disposal citing concerns for the longevity, stability, and
future exposure risks of on-site disposal. Some commentors suggested that leaving
contaminated materials on site would not provide a permanent solution and would only
be a toxic legacy for future generations. Another commentor expressed the opinion that
any material hauled off site would be a liability for another community.
RESPONSE: EPA agrees with the commentor's description of the advantages of off-site
disposal. But a significant disadvantage is the cost of off-site disposal, nearly $50 million
more than disposal in an OCF. Together with the fact that not all contamination will be
removed from the Site under any alternative (e.g., 15 million tons of slag cannot be
removed) EPA has determined that the cost-effective cleanup solution at the Site is
disposal of source area soils in an OCF and placement of a soil cap over the entire Site.
If materials were disposed off-site, it would most likely be placed in a permitted and
regulated hazardous waste facility which has already been constructed and permitted and
should, therefore, not be a liability for another community.
61. COMMENT: One commentor expressed the opinion that development of the Asarco Site
should not be allowed unless the soil is removed off site.
RESPONSE: EPA believes that the Site can be safely developed if the contaminated soil
that remains on site is either isolated in an OCF or capped in place.
2.8 MONITORING/LONG-TERM CONTROLS
62. COMMENT: Several commentors expressed the opinion that any contaminated material
remaining on site in an OCF or underneath a cap should be surrounded by monitoring
wells and tested regularly. One commentor asked if a program would be established and
funded to ensure ongoing monitoring and repairs when necessary. Another commentor
wondered who would be responsible for ensuring that the post-cleanup monitoring is
performed.
RESPONSE: Fifty-eight monitoring wells are being used for sampling under the long-term
monitoring program. EPA and Asarco have agreed to install additional groundwater
monitoring wells after source areas soils have been excavated (see the "Post-RI Long
Term Monitoring Sampling and Analysis Plan," October 1994). All of the wells in the
source areas will be sampled quarterly. During the design of the OCF, EPA will ensure
that monitoring wells are in appropriate locations to detect problems with the OCF should
they occur in the future. Asarco will be responsible for maintaining and repairing all wells
as necessary. EPA will ensure that Asarco monitors the Site after all cleanup activities
are completed.
63. COMMENT: One commentor suggested that local land trusts, public agencies (Housing
Authorities), and environmental groups should be involved in future site monitoring and
management responsibilities.
2-19
-------
RESPONSE: EPA believes it is most appropriate for Asarco to have responsibility for all
future monitoring activities. But, EPA is planning to involve other entities in monitoring
and management activities.
64. COMMENT: One commentor suggested that deed restrictions and other legal means for
ensuring institutional controls for the Asarco Site need to be strict to ensure a permanent
protection for the soil cap placed across the Site and any containment facility built on the
Site.
RESPONSE: EPA agrees (see Section 9.6.2 (a) of the ROD) and will include requirements
in the future agreements with Asarco to implement institutional controls including deed
restrictions.
65. COMMENT: One citizen commented that the Park District and Tacoma cannot be
counted on to keep their promise of post-development monitoring because they have not
kept previous promises.
RESPONSE: Asarco will be responsible for conducting all future Site monitoring,
including monitoring after the cleanup has been completed.
66. COMMENT: One commentor stated that regardless of whether Asarco treats the soil or
disposes it in an OCF; monitoring, cap maintenance, air monitoring, and surface water
monitoring must be required.
RESPONSE: EPA agrees that monitoring is necessary; these measures .are required in
the selected remedy found in Section 9.0 of the ROD.
2.9 HEALTH
67. COMMENT: Two commentors were concerned about health effects from contaminants
on site and believe that some of their dose family members have suffered from chronic
health problems and may have died prematurely as a result of working at the Asarco
Smelter.
RESPONSE: EPA expresses its regret for this commentors situation. EPA's cleanup
decision is based on the health risks posed by current conditions at the Site. EPA cannot
evaluate the extent to which workers' health may have been affected while employed at
the smelter, but EPA can assure that any future population which comes into contact with
the Site will not be adversely impacted.
68. COMMENT: One representative from the Washington and North Idaho District Council
of Labor voiced concerns about the health and safety of site workers participating in the
cleanup operation. He expressed the opinion that Hydrometrics has demonstrated
continuing disregard for worker safety and health concerns by allowing contaminated
vehicle/equipment rinse water to be discharged directly into Commencement Bay via
storm sewers.
RESPONSE: EPA requires Asarco to submit health and safety plans for all of the cleanup
activities that occur on the Site. During any cleanup activities, EPA has an oversight
contractor on site to ensure that the work plans and the health and safety plans are being
2-20
-------
followed appropriately. Any concerns about worker safety should be forwarded directly
to the Washington Department of Labor and Industries. See also Response to Comment
No. 22. During soil excavation and disposal activities, EPA will require Asarco to control
discharges of contaminated water.
69. COMMENT: The Puyallup Tribe requested that EPA take into consideration their hunting,
fishing and other subsistence activities on and near the Puyallup Reservation and added
that the living resources in Commencement Bay and human population that depends on
these resources must not be subject to the bioaccumulation of hazardous chemicals. The
Puyallup Tribe also stated that the protection of anadromous fish (species which live in
fresh and salt water), on which much of the tribe relies for spiritual subsistence and
economic survival, is of paramount importance. The Tribe requested that EPA conduct
a fish consumption study prior to issuing the ROD for the smelter cleanup.
RESPONSE: EPA has not evaluated how much fish from Commencement Bay is
consumed by the Puyallup Tribe in making its cleanup decisions in this ROD. EPA has
agreed, however, to consider this information when making its cleanup decision regarding
groundwater.
EPA is and will continue to take into account the concerns of the Puyallup Tribe, which
encompass the existence of contamination in all of Commencement Bay, not just that
associated with the Asarco Site. EPA has set its cleanup goals at levels which it believes
are protective of human health and the environment. Because "protectiveness" includes
minimizing contamination in fish that may be consumed by humans, EPA is particularly
focusing on contaminant levels in fish in its continued investigation of marine sediments
off-shore of the Site.
70. COMMENT: Two commentors felt that the health risks associated with the contamination
of the Asarco Site may be exaggerated because they have not experienced adverse
health effects from living near the Site. One commentor suggested that stress from the
cleanup process is probably more debilitating than the arsenic contamination, and the
other commentor expressed the opinion that EPA should offer a real-fife comparisons of
the alleged increased health risks from exposure to lead and arsenic.
RESPONSE: The potential health risks that have been identified at the Site in the Risk
Assessment are primarily based on predicted adverse effects posed by current Site
conditions to potential residents, workers, recreational visitors or trespassers, i.e., people
who may spend varying amounts of time at the smelter in the future. Because residents,
workers, etc. are not living/working/playing on the Site now, it is not possible to give real-
life examples. The evaluation of potential increased health risks from lead and arsenic
are summarized in Section 4.2 of the Risk Assessment (Kleinfelder, 1993).
Residential:
71. COMMENT: One person questioned whether or not it is safe to eat home grown produce
from the area.
RESPONSE: The Risk Assessment conducted for the Ruston/North Tacoma Study Area
indicated that the risk from eating fruits and vegetables that are grown in the area is very
small. Precautions which are recommended by the local hearth department include,
2-21
-------
thoroughly washing leafy produce such as lettuce, and produce which is grown
underground, such as carrots and radishes.
72. COMMENT: One person expressed the opinion that Asarco has been given "special
treatment" because the level of arsenic and lead contamination that it has been ordered
to excavate is greater than the Action Levels established by the State.
RESPONSE: EPA believes this commentor is referring to action levels for the residential
area. EPA disagrees that Asarco has been given "special treatment." EPA has selected
safe cleanup levels for the soils. Decisions regarding the cleanups of both the
Ruston/North Tacoma Study Area and the Smelter Site, including the specific
determinations of action levels, have been made in accordance with federal and state
requirements, and with the concurrence of the Washington Department of Ecology.
2.10 DEVELOPMENT/LAND USE
73. COMMENT: Numerous commentors expressed specific opinions regarding the
development that should occur at the Asarco Site after cleanup. One person commented
that, if the Asarco Site is beautified, surrounding property values would be elevated and
residents would be angered by the resulting increase in property taxes. One commentor
expressed the opinion that Asarco is living up to the public trust by their commitment to
invest 15 to 20 million dollars beyond the cleanup cost to encourage future development.
Another person commented that redevelopment would not compensate for the legacy of
pollution that Asarco will leave behind.
RESPONSE: All of the comments received by EPA regarding future development will be
forwarded to the Land Use Group which includes representatives from the City of
Tacoma, the Town of Ruston, the Metropolitan Park District and Asarco. EPA believes
that the cleanup of the smelter site will reverse the legacy of pollution from the operation
of the smelter. EPA is not in the position to evaluate the potential for property taxes to
change based on Site development activities.
74. COMMENT: Many commentors were concerned that only financial benefits, and not
environmental and/or long-term human health considerations, have been considered in
the Master Development Plan. Two of these commentors expressed the opinion that the
development plan was designed primarily to enable Asarco to save significant cleanup
costs. One person commented that when a company pollutes an area so badly it
achieves the distinction of worst Superfund site, a cursory cleanup for the sake of profit
and added local taxes does not meet the intent of Superfund legislation.
RESPONSE: EPA has selected cleanup measures that will comprehensively address
contamination at the Site and that are fully in accordance with the Superfund law.
Further, the primary intent of the Master Development Plan is to provide for future
development of the Site once cleanup has been completed. Accordingly, other than the
need to maintain the protectiveness of the cleanup measures, it is reasonable that the
Master Development Plan not focus on environmental considerations.
75. COMMENT: Several commentors suggested that development would hinder remediation
of groundwater and surface water and restoration of natural habitat and that development
should not be allowed until that portion of the Site is fully remediated. One commentor
2-22
-------
suggested that the cleanup be modified to include a provision that development may not
hinder remediation or restoration, and another commentor stated that development
should not occur until the effectiveness of a permanent remedy is clearly established for
surface water, groundwater, and sediments.
RESPONSE: The selected remedy requires that development activities not interfere with
potential cleanup activities, including the possibility that surface water and/or groundwater
treatment will be necessary in the future (see Sections 9.3 and 9.5 in the ROD).
76. COMMENT: Two commentors requested that Asarco separate the cleanup effort from the
commercial development of the Asarco site; one of these commentors requested that
Asarco acknowledge this separation publicly.
RESPONSE: These two processes are separate but contain common elements. EPA is
determining the environmental cleanup of the Site. The local municipalities and Asarco
will be facilitating the development of the Site.
However, EPA and the other parties involved recognize the advantage of combining some
of the planning elements for future development with the design of site cleanup activities.
For example, if Asarco and the local governments can identify the type and locations of
development (number of people, type of services necessary) then it can design the water,
sewer, electricity and phone lines at the same time Asarco and EPA are designing a cap
for the Site. This will allow the cap, with the necessary utilities, to be installed at one time
rather than installing the cap and digging it up later to install utilities.
77. COMMENT: Two people commented that if Asarco conducted the cleanup and did not
have enough money left over for development, the Asarco Site would -be redeveloped
anyway because it is prime valuable property. Two people added the comment that a
pollution free site and community would be the biggest asset to encourage development
in the area, and another commentor suggested that Asarco will redevelop the Site based
on economic reasons alone, regardless of any "Principles of Agreement" with the local
communities. One commentor expressed the opinion that the property would be more
valuable if there was not an OCR on the Site.
RESPONSE: By signing the "Agreement in Principle," Asarco and the local governments
committed to using their best efforts to develop the property. EPA hopes that all of these
parties will honor their commitments and that the former smelter will be returned to
productive uses for the community. EPA has no opinion on whether the Site would be
redeveloped if Asarco had insufficient funds.
78. COMMENT: The Town of Ruston commented that an important element necessary for
future development is EPA providing an appropriate release indemnification from liability
for Ruston, Tacoma, the Park District, the Public Development Authority, and future
lessees and lenders.
RESPONSE: At the national level, EPA Headquarters is committed to encouraging
development and reuse of Superfund sites. National policies and guidance regarding
such matters, including the potential liability associated with Superfund sites, are being
revised. EPA Region 10 will work with Headquarters' policies and guidance to provide
2-23
-------
as much certainty to potential owners, investors and tenants at the Asarco Site as
possible.
79. COMMENT: The Town of Ruston commented that the design and implementation of
remediation must support the Master Development Plan by allowing appropriate areas of
the Asarco Site to be cleaned in a timely manner, thus opening these areas to
development prior to completion of the remediation of the entire Site.
RESPONSE: EPA's intent is to allow development of the Site in a timely manner.
However, EPA's primary concern is the safety and well-being of the site workers,
surrounding residents and any potential future users of the Site. Development activities
will be allowed to proceed when it is certain they will not interfere with cleanup of the Site.
2.11 COSTS
80. COMMENT: Several commentors expressed the opinion that Asarco has made great
financial gains at the expense of the environment and should be held financially
accountable for a thorough cleanup. One commentor expressed the opinion that the
revenue generated by Asarco during its operation and the revenue that will be generated
after development will far exceed the cost of any cleanup.
RESPONSE: Under the Superfund law, Asarco is liable to perform (or pay for) the
cleanup selected by EPA. The cleanup must attain specific statutory mandates, including
protection of human health and the environment. The amount of money that may have
been generated by Asarco while the smelter was operating (or could be generated after
cleanup) does not influence the extent of cleanup necessary to be protective and
therefore is not considered by EPA when selecting a cleanup.
81. COMMENT: Several commentors indicated that the extra cost for treatment of the
contaminated soils should not be a factor in determining the best cleanup alternative.
RESPONSE: One of the requirements for cleanups selected under the Superfund law is
that they are cost-effective. EPA uses several factors to determine whether cleanup
measures are cost-effective, including comparing the relative costs and effectiveness of
various cleanup alternatives. Based on EPA's analysis and review of the comments
received, EPA believes that the additional "effectiveness" provided by treating soils is not
worth the increased cost compared to disposing soils in an OCF.
82. COMMENT: One commentor posed two cost-related questions: How much will it cost
to treat the soil and store it in an OCF, and how much will it cost to clean the aquifers?
RESPONSE: EPA estimates that it would cost $70 million to treat source area soils,
dispose the treated soils in an on-site solid waste landfill, and dispose the demolition
debris in an off-site hazardous waste landfill. (This option is approximately $20 million
more than soil treatment/disposal beneath the Site cap and $47 million more than soil
disposal without treatment and debris disposal in the OCF.)
Asarco has estimated that the cost of pumping and treating groundwater for 2 years and
30 years at $15.6 million and $20.1 million, respectively. Using an in-situ (in place)
groundwater treatment method would cost $1.3 million and using in-situ groundwater
2-24
-------
treatment by seawater injection would cost $1.5 million for 30 years. Given the
uncertainty of whether these groundwater measures would be effective in cleaning up the
aquifers, EPA has determined that it is appropriate to take the source control measures
identified in the selected remedy and then evaluate what, if any, further groundwater
cleanup activities are necessary.
83. COMMENT: One citizen expressed the opinion that the billions of dollars spent on the
Superfund program in the U.S. is disgraceful and has shown very few results.
RESPONSE: EPA disagrees. Accomplishments under the Superfund program include
performing thousands of short-term removal actions (e.g., responding to emergency spills,
etc.), completing major cleanup construction activities at over 278 sites, and starting
major cleanup activities at more than 430 sites.
84. COMMENT: One commentor expressed the view that millions of dollars have already
been wasted trying to determine the best cleanup method for the Asarco Site.
RESPONSE: EPA and Asarco have spent significant time and money to determine the
types and locations of contamination on the Site and how the Site can be cleaned up.
These evaluations are necessary and worthwhile and will result in an efficient cleanup.
85. COMMENT: One commentor expressed the opinion that Asarco should have been
responsibly setting aside money for cleanup every year since the Site was deemed to be
part of a Superfund site. Another commentor stated that Asarco had a savings account
for contamination cleanup in excess of $150 million dollars.
RESPONSE: Asarco will be required to fund the amount necessary for cleanup of the
Site. How Asarco chooses to pay for the cleanup is its own decision.
86. COMMENT: One citizen was dismayed at the amount of money Asarco was spending
on its public relations campaign, stating that the money spent sending her leaflets,
correspondence, and Christmas cards would be better spent on cleanup of the Asarco
Site.
RESPONSE: EPA will not credit or deduct the amounts Asarco has spent on public
relations campaigns from the amount it will be required to spend on cleanup.
2.12 PUBLIC INVOLVEMENT
87. COMMENT: Many commentors expressed the opinion that Asarco is trying to pressure
the public into accepting the provisions of the "Agreement in Principle," including the less
expensive on-site containment option, in exchange for development money. Two
commentors suggested that Asarco has "bought off1 the officials from Ruston, Tacoma,
the Park Board, and other community agencies. Another commentor expressed
frustration with Asarco's "carrot and stick" tactics to keep contamination on the Site and
requested that EPA weigh-in on the side of the public when making its decision. One of
these commentors suggested that there will be a lot of alienation against the EPA if the
OCF is not approved.
2-25
-------
RESPONSE: EPA believes that the community participation in planning for the future
development of Site was important and beneficial to the community. The local
governments and Asarco succeeded in providing many sessions for community members
to express their point of view and then took their comments and used them to develop
an overall design strategy for the project.
It appears that one reason Asarco spent a lot of time and money on the development
project was in hopes that a less expensive cleanup option would be supported by the
community. For the past 4-6 years elected representatives of the community had been
strongly opposed to an OCF. During the land development sessions, the facilitators were
able to understand what the objections and concerns were about on-site disposal and
were able to design a preliminary development plan to address these objections and
concerns.
Asarco's efforts were very public, as was the approval of the "Agreement in Principle," by
the councils in Ruston and Tacoma, and the Park Districts' board. The local governments
recommended to EPA that an OCF be selected. The charge that Asarco has "bought off'
public officials is unfounded. During the public comment period, EPA received
approximately 830 out of a total of 900 cards and letters of support for an OCF and future
development. EPA shares the opinion of these commentors that an on-site containment
facility can be constructed to protect human health and the environment.
Independent of the land use community participation sessions, EPA sponsored 2 public
meeting and spoke at 10 meetings with local community groups such as the Rotary Club
and the Environmental Commission of the Chamber of Commerce. The overwhelming
message heard at all of these meetings was support for on-site disposal of soil and
debris.
88. COMMENT: Several people commented that the EPA should make the best and safest
cleanup decision possible, without public influence, pressure from the land use committee
and/or development considerations. Some of these commentors suggested that the
propaganda and development money offered by Asarco may be tainting the approach by
the federal government to the cleanup and that EPA should keep these considerations
separate from the cleanup decision. One commentor was disturbed by Asarco's
seemingly "manipulative" pamphlet Conversely, two commentors expressed the opinion
that the EPA use a more democratic process to decide the cleanup method for the
Asarco Site and give greater consideration to public opinion.
RESPONSE: Public comment on EPA's cleanup decision is an important part of the
remedy selection process. In this case, EPA encouraged the land use process to occur
prior to issuance of EPA's Proposed Plan in order for the agency to fully understand the
needs of the community and not preclude future development options needlessly.
Nonetheless, EPA's paramount concern is protection of human hearth and the
environment, which will be achieved by the cleanup remedy that EPA has selected for the
smelter site.
89. COMMENT: Several commentors commended Asarco, the municipalities, and the
community for coming together to work on a major urban revitalization plan. Some
commentors stated that this project is a demonstration of how EPA can work with the
community to promote environmental remediation and economic development.
2-26
-------
RESPONSE: Although we are not done yet, EPA is also pleased with the work the Land
Use Group has completed and believes that working on Site cleanup together with future
development of Superfund sites is an effective approach.
90. COMMENT: One citizen would like to know what she can do to help, and which
politicians have expressed concern or provided assistance.
RESPONSE: There will be many opportunities for community involvement during the
development of the environmental cleanup design work plans. EPA will send out Fact
Sheets that describe ongoing work and also provide notice of opportunities for the public
to participate. In addition, EPA anticipates that the Land Use/Development Group will
continue to sponsor community sessions in order to refine the uses for the "development
zones."
Many of the elected and appointed representatives of Ruston, Tacoma and the Park
District have been involved in the land use and cleanup processes, such as:
Phil Parker, Mayor of Ruston
Charlene Hagen, Ruston Town Council
Ray Corpuz, City Manager of Tacoma
Paul Miller, Tacoma City Council
Jim Montgomerie, Metropolitan Park District
91. COMMENT: One person was dismayed by the course of events at the Pierce County
Council meeting because she felt that the environmental aspects of the cleanup were not
adequately addressed, only development and financial topics were discussed in detail.
She also expressed the opinion that most of the people in the community are not
adequately informed of EPA's cleanup proposal.
RESPONSE: EPA was not notified of the County Council meeting. EPA uses various
ways to keep the public informed, such as Fact Sheets, public meetings, news ads,
mailing lists, TAG Grants and information repositories. We are always open for any
suggestions, so please let us know of your ideas. EPA believes that by the end of its 90-
day public comment session and the Asarco Week #4 meetings that hundreds of local
community members were aware of and had participated in the cleanup and planning
decisions for this Site.
2.13 MISCELLANEOUS
92. COMMENT: One commentor believes that the following statement is not complete and
does not address the other characteristics of dangerous wastes as defined in Washington
State Dangerous Waste Regulations (WAC 173-303): "Waste that is not a federal
hazardous waste but has the potential to migrate into the environment would be disposed
in a solid waste landfill that meets state requirements (Page 23, Paragraph 5 of the
Proposed Plan)." He asked if the Toxicity Characteristic Leaching Procedure (TCLP) is
the only criterion that was used to make the determination.
RESPONSE: The statement in the Proposed Plan was intended to clarify that soils not
regulated under federal law (e.g., treated soils that pass the TCLP test) may still need to
be disposed in a landfill that met state solid waste landfill requirements. This
2-27
-------
determination would have been based on the results of water leaching tests showing that
disposal of treated soil would not be protective of the environment. The state has
specified its requirements for disposal of dangerous waste in WAC 173-303. The state's
determination of "dangerous waste" can be based on metal concentration as well as TCLP
leachate concentration.
Because EPA has selected the OCF, the untreated soils that will be disposed on site are
a federal hazardous waste. Therefore, the OCF will meet both federal and state
hazardous and dangerous waste requirements for landfills.
93. COMMENT: One person suggested that Asarco has profited at the expense of the
environment because of the lack of environmental concern on behalf of the local
governments. This commentor stated that the 'Tacoma Aroma" is symbolic of the way
the local governments have been dominated by industry. This commentor added the
example of the local water treatment plant that has been in violation of EPA standards for
years, however the city has chosen to pay the fine rather than remedy the problem.
RESPONSE: EPA encourages the commentor to express his/her views directly to the
appropriate local governments.
94. COMMENT: Several commentors expressed the opinion that the EPA has done a good
job in its development and presentation of the preferred alternative and Proposed Plan.
RESPONSE: EPA appreciates the comment.
95. COMMENT: Several public agencies, the Washington Department of Natural Resources,
Citizens for a Healthy Bay, and the Puyallup Tribe commented that they would like to
have greater involvement and input in the development and planning of the Preferred
Alternative/Proposed Plan. Additionally, the Puyallup Tribe requested that EPA act in
concert with Federal Indian Policy and consult with the tribe on whether the Proposed
Plan is consistent with Environmental Justice policies.
RESPONSE: All of these organizations participated on the Coordinating Forum (local,
state and federal representatives with an interest in the Asarco Smelter project) which was
convened in July 1993. Policy makers and staff members from local government, local,
state and federal health departments, and environmental representatives participated in
all aspects of reviewing and commenting on the cleanup alternatives and future land use
concepts. EPA will encourage these same organizations to participate in remedial design.
Consistent with EPA's Indian Polich, EPA's Regional Administrator met with
representatives of the Puyallup Tribe on March 16,1995, to consult on a govemment-to-
government basis on all of the Tribes concerns. EPA believes that the Proposed Plan is
consistent with its regional Environmental Justice principles.
96. COMMENT: The Puyallup Tribe reiterated the Clinton Administration's policy that "people
of color and the economically disenfranchised should not be forced to bear unfair
environmental burdens" (Executive Order 12898, Federal Register 7629).
RESPONSE: EPA believes that the cleanup it has selected is fully in accordance with the
objectives and requirements of Executive Order 12898.
2-28
-------
97. COMMENT: Several commentors were troubled by the estimated time for completion of
the cleanup. They believe that the cleanup action has taken too long already and/or that
the cleanup process and consequent development should be expedited. Other
commentors requested EPA to take time to carefully consider public comments and to
make scientifically sound decisions.
RESPONSE: EPA has reviewed all of the comments received during the public comment
period. It is EPA's intent to work with Asarco and the local municipalities so that cleanup
activities can begin as soon as possible. One approach to ensure that Site cleanup will
not be delayed is that when the Site is ready to be capped, even if all of the residential
soils from the surrounding neighborhoods have not been removed, a cap will be installed
and the Ruston/North Tacoma soils will be disposed in an appropriate off-site disposal
facility, see Section 9.0 of the ROD.
98. COMMENT: One commentor expressed concern about the noise that the cleanup project
would generate.
RESPONSE: Heavy equipment and machinery will be used during the cleanup but EPA
will require Asarco to reduce the noise to the extent possible by limiting the work hours
and selecting dedicated routes that trucks and traffic can use. Local residents and
government will have an opportunity to participate in the development of these plans.
99. COMMENT: One commentor believed that the stack bricks would be removed after
demolition, however was surprised to learn that they would only be covered with dirt.
RESPONSE: The stack bricks were covered with dirt after the stack was demolished in
January 1993. However, the selected remedy calls for these bricks to be unburied and
permanently disposed in the OCF.
100. COMMENT: The Puyallup Tribe commented that the nine criteria used to analyze the
alternatives should not all be given equal weight. They stated that the protectiveness of
human health and the environment and compliance with ARARs are the most important
threshold criteria.
RESPONSE: Section 8.0 of the ROD explains how EPA evaluated the cleanup alternatives
using the nine criteria. EPA emphasizes the importance of protectiveness and
compliance with ARARs by designating them as "threshold criteria." This means that an
alternative was not evaluated further if it did not meet these criteria.
101. COMMENT: One commentor expressed the opinion that, given the hazardous waste sites
for which Asarco may also be responsible for in Montana and Colorado, Asarco is the fifth
worst polluter in the country and possibly the world. This commentor also expressed the
opinion that "Asarco's long-standing policy appears to be coverup and not cleanup."
RESPONSE: Asarco will be held responsible for cleaning up the former Asarco Tacoma
smelter as well as other sites.
102. COMMENT: One commentor expressed the opinion that Asarco should have been forced
to clean up and redevelop the Site years ago, and that Asarco has needlessly delayed
clean up and redevelopment of the Site through endless litigation.
2-29
-------
RESPONSE: Actually, to date there has not been litigation associated with the cleanup
itself. Since 1986, EPA and Asarco have focused on the investigation of the Site, the
analysis of potential cleanup alternatives, and the demolition of smelter buildings and
structures.
103. COMMENT: One person commented that the cleanup method and development plan are
irrelevant as long as his commute to work is not affected, and the new development is
clean, legal, and profitable.
RESPONSE: EPA believes that the cleanup method and development plan are very
relevant to the future of the community overall. EPA notes, however, that the community
should expect that roads around the smelter may need to be closed during parts of the
cleanup.
104. COMMENT: One commentor requested that the public comment period be extended
past the October 11,1994, deadline.
RESPONSE: The public comment period was extended to November 10, 1994, based
on citizens' requests.
105. COMMENT: One commentor requested that interested parties be provided with a
straightforward comparison between EPA's preferred alternative and the alternative
proposed by the land use committee.
RESPONSE: The majority of the cleanup activities identified in EPA's selected cleanup
remedy are also identified in Paragraph 7 of the "Agreement in Principle. However, EPA's
selected remedy, see Section 9.0 of the ROD, provides more detail than the "Agreement
in Principle" as to why many of the cleanup measures are necessary. Both the
"Agreement in Principle" and the Selected Remedy require the cleanup to be protective
of human health and the environment over the long term.
Common Elements of the "Agreement in Principle" and EPA's Preferred Alternative.
• Utilization of Ruston/North Tacoma residential soils as the sub-base for the plant
and breakwater (slag peninsula) cap
• Monitoring and institutional controls
• Abandonment of the production well
• Installation of groundwater/surface water interceptor trenches
• Replacement of the existing drainage system, including outfalls
• Shoreline armoring
Additional Elements of EPA's Proposed Plan.
• Treatment of source area soils by solidification/stabilization and disposal as a sub-
base to the site-wide cap
• Demolition of remaining buildings and structures
• Mitigation measures if wetlands or intertidal habitat are adversely impacted by
cleanup activities
• Safety measures
• Integration of cleanup with land use plans
2-30
-------
It should be noted that EPA's Selected Remedy in the Record of Decision selected
disposal of soil without treatment in an OCF rather than soil treatment with
solidification/stabilization. The "Agreement in Principle" also identified disposal of soil
without treatment in an OCF. Other elements of the Selected Remedy are very similar to
the elements in the Preferred Alternative described above.
106. COMMENT: One Metropolitan Park Board member commented that he did not sign the
"Agreement in Principle" because he did not have the opportunity to fully analyze the
situation and he was pressured, lied to, and threatened. He also stated that the
Metropolitan Park Board has not agreed, passed, or discussed the "Agreement in
Principle," nor have they authorized any letters to be directed to EPA.
RESPONSE: EPA's understanding is that the Metropolitan Park Board did pass and sign
the "Agreement in Principle" with all but one supporting vote. EPA suggests that this
member talk directly with fellow Board members.
107. COMMENT: One commentor expressed the opinion that, based on the information on
page 13 of EPA's Proposed Plan, it appears that all of the approaches are protective of
public health and the environment and that it is difficult to determine which options are
truly protective.
RESPONSE: On page 9 of the Proposed Plan, EPA provided all of the cleanup
alternatives that were considered. On page 21, EPA explained that the no-action
alternatives are not protective of human health and the environment and thus were not
further evaluated under the nine criteria." Otherwise, EPA believes that any of the
remaining alternatives (other than monitoring and limited action) would have been
protective of human health and the environment.
108. COMMENT: The Town of Ruston requested that EPA respect the permitting processes
of the local governments (Ruston, Tacoma, Park District) and not preclude or usurp their
authorities to require Asarco to obtain any and all infrastructure permits, and that these
municipalities would like to review remediation plans.
RESPONSE: EPA agrees that it is important to work within the established permit
processes of the local governments. EPA's expectation, however, is that these processes
will not result in delays to cleanup activities.
2-31
-------
3.0 ASARCO'S COMMENTS AND EPA RESPONSES
As part of an effort to obtain public comment regarding the Master Development Plan, Asarco
distributed self-addressed, postage-paid comment cards to the public at several community
meetings. Two different card types were distributed by Asarco during this effort, the first batch
of cards were entitled, Tell EPA what you think of the Asarco Land Use Plan", and included the
statement, "I want the Asarco Site redeveloped;14 the second batch of cards were entitled Tell
EPA You Support the Asarco Master Development Plan," and included two statements to select
from: "I support development of the Asarco Site and the on-site containment facility" and "I would
like additional information about the plan and community meetings." Additional space was
provided on both cards to include comments and the respondent's address/phone number.
A total of 673 comment cards were forwarded to EPA by Asarco during the public comment
period. Based upon the type of comment card and the nature of the reply received, EPA has
tallied and separated the cards into the five following general categories with regard to cleanup
preference:
• 547 comment cards were marked in favor of the development of the Asarco Site
including an on-site containment facility.
• 69 of the comment cards, respondents offered specific comments and
suggestions for development of the Asarco Site, but not a preferred cleanup
method.
• 24 of the comment cards, respondents indicated that they would like additional
information and/or expressed specific questions, but did not state a cleanup
preference. The questions have been summarized and responded to in Section
2.
• 19 respondents indicated that they were either opposed to the OOP or suggested
a combination of on-site containment and treatment.
• 14 of the comment cards, respondents offered miscellaneous suggestions and
comments, but did not indicate their cleanup preference.
EPA notes that many individual commentors sent their letters and "reply cards" directly to EPA
and that most of these commentors also stated they were in favor of future development and an
OCF.
In addition to comments received from citizens, local officials, and Natural Resource Trustees,
EPA received comments from Asarco, Inc., the Potentially Responsible Party for this Site. The
comments below summarize Asarco's overall concerns as well as its specific technical concerns
with the Proposed Plan. As a member of the Land Use Group, Asarco did not support EPA's
Preferred Alternative of soil treatment based on cost, long-term effectiveness and because it
believes that treatment would preclude the implementation of future land development plans.
3-1
-------
GENERAL COMMENTS
1. COMMENT: Asarco believes that although the cleanup decision is separate from the
plans for future use of the Site, that the terms of the "Agreement In Principle" should be
a significant factor to modify EPA's remedy when using the nine criteria analysis. Asarco
believes that even if soil treatment and on-site containment facility (OCF) were "equal" with
respect to the threshold and balancing criteria, that the community support for and on-site
containment should compel EPA to select and OCF.
RESPONSE: As a modifying criteria, community acceptance, could result in EPA favoring
a feasibility study alternative that was otherwise equal with respect to all of the other
threshold and balancing criteria. As stated in the Proposed Plan, EPA recognizes that
in addition to cleaning up contamination at the Asarco Site, that the community is very
interested in Site development as well. As a result, EPA received numerous comments
from community members, community leaders and local businesses and groups
supporting an OCF and future site development. It was these comments, in addition to
the "Agreement in Principle," that convinced EPA that the selection of the OCF would be
the best cleanup remedy.
2. COMMENT: Asarco stated that on-site containment meets both of the threshold criteria
described in the "nine criteria:" (1) Protection of human health and the environment and
(2) all Applicable and Relevant and Appropriate Requirements (ARARs) and on-site
containment facilities (OCFs) have shown their effectiveness over the long term at sites
throughout the country.
RESPONSE: EPA agrees that either soil treatment or on-site soil containment meet the
two threshold criteria and that an OCF can be designed to be protective over the long-
term.
3. COMMENT: Asarco stated that EPA's Proposed Plan is not "cost-effective," nor does it
"utilize a permanent solution and alternate treatment technologies or resource recovery
to the maximum extent practicable" which are two of five balancing criteria described in
the "nine criteria." Asarco believes that cost-effectiveness is a "condition (emphasis
added) for remedy selection, not merely a consideration during remedial design and
implementation," (55 F. Reg. 8726), and that "cost-effectiveness" is based on the selected
remedy's overall effectiveness which is described in § 300.430 (f)(1)(i)(B) of the National
Contingency Plan (NCP) as long-term-effectiveness and permanence, reduction of toxicity,
mobility, or volume through treatment, and short-term effectiveness.
RESPONSE: EPA has made a determination in the ROD that disposal in the OCF is the
cost-effective remedy (see section 10.3 of the ROD). This determination is based on
EPA's finding that disposal in an OCF is an effective approach for isolating soil and debris
from the environment and because disposal in an OCF is estimated to cost nearly $30
million less than treatment of soil. In addition, the community clearly stated that it
believed that selecting an OCF would allow future development opportunities at the Site.
4. COMMENT: Asarco also stated that increased cost of treatment would not result in a
commensurate decrease in risk at the Site.
3-2
-------
RESPONSE: EPA believes that the primary issue raised by the choice between treatment
and soil was not the reduction in risk, which would be comparable, but the ability to
select a remedy that would remain protective over the long-term and be compatible with
future plans for the Site.
5. COMMENT: In addition, Asarco identified several additional reasons why soil treatment
should not be selected. These reasons are:
• there is no evaluation of the effectiveness of treatment over many years;
• the cost of treatment is prohibitively high ($150/ton);
• the amount of additive required results in a low density product resulting in a
significant increase in volume of treated material;
• the physical properties of the treated material raise implementability questions with
respect to future plans for Site development; and
• the longer time for remediation would have serious negative effects on future land
use plans.
RESPONSE: EPA's response is as follows:
(1) EPA agrees. Although as noted in Response No. 21 in Section A, landfills have also
not been around for a significant number of years either. (2) The cost of treatment, re-
evaluated in context of the responses received from the community, indicated that a less
costly and equally protective cleanup was preferred. (3) Although it is not clear how/if
the increased soil volume would have impacted Site development, EPA believes that this
could have been factored into Site plans in the future. (4) EPA agrees that the
appropriate places on the Site would have had to have been identified to ensure
comparability of soil treatment with Site development. (5) EPA is not sure why Asarco
believes that soil treatment would take longer than construction and filling an OCF. The
Feasibility Study states that treatment would take 6 months and the OCF alternative could
take up to 2 years.
6. COMMENT: The overwhelming community support for the "Agreement in Principle"
should result in the selection of a containment alternative as the remedy and the NCP
allows EPA to select an alternative favored by the community over an equally protective
alternative.
RESPONSE: EPA has selected an OCF as part of its selected remedy, see Section 9.0
in the ROD.
7. COMMENT: The ROD should acknowledge the work currently being conducted under
the Administrative Order on Consent which was signed by EPA and Asarco in 1994, and
allows maximum future flexibility in any modifications to the current shoreline so that the
uplands and marine remedial actions can be integrated in a reasonable and cost-effective
manner, in addition, Asarco stated that CERCLA does not authorize EPA acting alone
to impose habitat restoration or mitigation as part of a remedial action, but instead, states
that restoration measures may be agreed upon by the PRP and the natural resource
trustees.
RESPONSE: EPA acknowledges that sampling and analysis activities are being
conducted under the 1994 AOC. Integration of the cleanup of sediments and cleanup of
3-3
-------
uplands portions of the Site is a worthwhile objective but is not a specific provision of the
AOC. During the development of the work plans for Site cleanup, EPA will work in
conjunction with Asarco, the natural resource trustees and the community to develop the
necessary mitigation measures for the Site, see Section 9.0 of the ROD. EPA agrees that
restoration measures (i.e., to compensate for past injuries to natural resources) will be
determined by Asarco and the natural resource trustees.
8. COMMENT: The ROD should resolve the issue of the Ruston/North Tacoma Study Area
residential soils disposal and should set performance standards, rather than numerical
remediation goals, for groundwater monitoring.
RESPONSE: The selected remedy for the Ruston/North Tacoma residential soils is to
place them beneath a cap (e.g., used as a sub-base) in areas that will not be impacted
by groundwater, see Section 9.0 of the ROD. The ROD identifies measures to control the
sources to groundwater (e.g., soil excavation, containment and capping and replacing the
surface water drainage system) and monitors the effect of these activities. The Class III
preliminary remediation goals will be used as bench marks to evaluate the impact of
source control activities on groundwater that enters Commencement Bay.
9. COMMENT: There are some fundamental differences between EPA's preferred remedy
and the remedial actions proposed as part of the Agreement in Principle. The primary
differences involve how soil is handled after excavation from source areas.
RESPONSE: EPA has selected disposal of source area soil in an OCF in the Record of
Decision.
10. COMMENT: Treatment of a portion of excavated soils, the arsenic kitchen soils for
example, would be prohibitively costly.
RESPONSE: EPA believes that treatment of any part of the excavated soils before
disposal in an OCF would certainly add to the overall cost of the cleanup. Because
several commenters recommended that some or all of the soils be treated before placing
them in an OCF, EPA evaluated the environmental benefits of treatment. In this analysis,
see Appendix D, EPA has determined that treatment of the most contaminated source
area soils would not substantially decrease the potential impact on groundwater from
leachate. EPA has not selected treatment of soils as part of the ROD.
11. COMMENT: Over 70 physical, chemical, biological and thermal treatment processes were
examined for potential application for the smelter site. Among the technologies
investigated for site specific applications for the site were soil washing, soil acid leaching,
and soil fixation.
The studies showed that soil washing and/or leaching was not applicable for the site
because of difficulties with physical and chemical conditions of site soils. Technical
problems with soil leaching included incomplete removal of arsenic, failure of leached or
washed materials to pass TCLP after treatment, and additional treatment requirements
associated with acid fluid treatment and subsequent disposal.
3-4
-------
Two commercial vendors were able to demonstrate, in the short term, attainment of
treatment objectives. However, projected treatment costs are high and considerably more
expensive than other soil options including the use of an OCF.
RESPONSE: EPA believes that soil treatment by solidification/stabilization could be
effective over the long-term. The additional studies conducted by Asarco indicate that the
TCLP test results are slightly less effective after 28-day testing (but are still significantly
below hazardous waste regulatory threshold levels for treatment) and that the volume of
the treated material increased by approximately 60%. EPA did not select treatment,
however, because soil can effectively be isolated in an OCF, the OCF was much less
expensive than treatment, and because the majority of commenters supported disposal
in an OCF in conjunction with land use plans.
SPECIFIC COMMENTS
All of the following comments from Asarco refer to EPA's Proposed Plan, dated August 10,1994.
12. COMMENT: Page 4, fourth paragraph, first sentence. The sentence should read
"surface water features on the smelter property include surface water in the cooling
pond...." There is no longer surface water flow into the pond and surface water flow has
been diverted around the cooling pond since Spring 1993.
RESPONSE: This comment has been incorporated into the "Background" section of the
ROD and it now states that, "Surface water features on the smelter property include
surface water in the cooling pond..."
13. COMMENT: Page 5, legend to Figure, "known sources" should be changed to "identified
source areas"
RESPONSE: The clarification has been made in revised Figure 1-1.
14. COMMENT: Page 6, first paragraph, last sentence. The remedial investigation
identified six areas as source areas of arsenic and metal concentrations to groundwater,
based primarily on the association of these areas with elevated concentrations in
groundwater. Of these areas, the arsenic kitchen and the southeast plant area have
subsurface soil data that support the hypothesis that these areas contribute arsenic and
metals to groundwater. The stack hill contributes arsenic and metals to surface water
where groundwater "daylights" through soils that contain elevated arsenic and metals.
Available soil and water data from the cooling pond suggest there are little impacts to
groundwater, from this source; however, the pond is considered a source area because
of its total sediment arsenic and metal concentrations and because of its historic use as
a process water pond that stored water containing elevated arsenic and metals. The
remaining areas (copper refinery area and fine ore bins area) are assumed groundwater
sources primarily because of their association with elevated groundwater concentrations
and known history of these facilities. Soils in these areas were assumed to be sources
to groundwater for feasibility study purposes; however, insufficient data are available to
positively establish soils from these areas as groundwater arsenic and metal sources.
The sentence would be more representative of actual site conditions if it read These are
areas that appear to act as the primary sources".
3-5
-------
RESPONSE: The ROD states that, "These are areas that have either the highest
measured concentrations of contaminants in the soils, appear to act as the primary
known sources of contamination to groundwater and surface water, and/or have large
amounts of contaminated material based upon the historic uses of these areas."
15. COMMENT: Page 6, second paragraph, first sentence. The first sentence is not true.
First, the areas have not been identified based on the presence of the "highest known
concentrations11 but, instead, based on their association with highest groundwater
concentrations of arsenic and metals. In some cases, such as the arsenic kitchens and
stack hill areas, these areas do contain some of the highest total soil metal
concentrations, but, more importantly, also the highest leachate soil concentrations.
However, some of the identified source areas are not associated with confirmed total soil
data. For example, to date the soil quality underneath the fine ore building has not been
tested. Second, not all metals and/or organic chemicals are "highly mobile and leaching
out of soils or slag." The sentence should be changed from "...which are highly mobile
and are leaching out of soils or slag..." to "...which may be leaching out of soils or slag..."
Also, the suggestion that high metal values automatically result in principal threats to
groundwater is not correct. High metal values in themselves are not an indication of a
threat to groundwater, as demonstrated by slag. The threat to groundwater is determined
by teachability and subsequent mobility of a chemical.
RESPONSE: See response to Comment No. 14.
16. COMMENT: Page 6, fourth paragraph,, last sentence. The statement that, "Most of the
slag portions of the Site appear to contribute less contamination... as compared to the
source areas..." is incorrect. AH slag contributes less than the source areas. However,
this effect can be obscured by other sources, such as is the case for the slag located in
the plume down-gradient from the arsenic kitchen. It would be representative of actual
conditions if this sentence was changed to read: "Slag appears to contribute less metals
to groundwater...as compared to the source areas..."
RESPONSE: The ROD states that, "The slag portions of the Site appear to contribute less
contamination to groundwater as compared to the source areas described."
17. COMMENT: Page 6, sixth paragraph, second sentence. It is not certain pipes are filled
with sediment or that they are cracked. Because of the age of the plant, an assumption
was made in the FS that drainage lines were cracked and that sediment in pipes was
possible. A suggested change to the sentence is "pipes may be cracked and/or contain
contaminated sediment."
RESPONSE: The ROD states that, 'The pipes and drains associated with the system may
be cracked and/or the pipes filled with contaminated sediments."
18. COMMENT: Page 6, ninth paragraph, last two sentences. Based on site data, it is
apparent that smelter site groundwater arsenic and metals are more affected by low redox
conditions associated with the presence of organic material than by resultant pH
conditions. The presence of seawater apparently buffers groundwater in the southeast
plant area and pH concentrations are typically above 8 indicating acidic conditions at this
location are not occurring.
3-6
-------
RESPONSE: The language in the ROD is revised to read that wood waste buried in the
slag is decomposing, thus contributing to the release of metals, particularly arsenic, from
the slag.
19. COMMENT: Page 6, last paragraph, first sentence. The metal levels in groundwater
do more than just "appear" to decrease as groundwater moves toward the bay; the data
indicate that this decrease is a fact. We suggest changing this sentence to read; 'The
metal levels in groundwater decrease as groundwater moves through smelter property
toward Commencement Bay". Although the cause of the decrease remains a subject of
debate, as pointed out by the description of potential causes in the following sentence,
the metals levels decrease is documented by validated data.
RESPONSE: The ROD states that, The metal levels in groundwater decrease as
groundwater moves through the smelter property towards Commencement Bay." EPA
agrees that the reason(s) why this decrease occurs has not yet been established.
20. COMMENT: Page 7, first paragraph, last sentence. No large cracks as described in
the proposed plan have been identified during the RI/FS. The crack hypothesis is entirely
of regulatory origin. Although one well had a higher test permeability than surrounding
wells, the significance of the well test relative to groundwater metal transport is not clear.
All available evidence indicates that dilution and/or adsorption are occurring to the same
degree in the central portion of the site. If anything, dilution and/or adsorption are
probably most effective hi the central portion of the site, as evidenced by the substantial
decrease in metals concentrations over relatively short distances.
RESPONSE: This sentence was not included in the ROD.
21. COMMENT: Page 7, EPA's Cleanup Objectives, first sentence, cleanup actions
necessary because of "long-term cancer risks for workers*. Long-term cancer risks
to sealife and animals were not evaluated as the sentence implies.
RESPONSE: Risks to sealife and animals were qualitatively evaluated in EPA's ecological
risk assessment. EPA's conclusion was that sealife has been adversely impacted by
releases from the Site and that the Site posed risks to terrestrial animals and vegetation.
22. COMMENT: Page 8, Contaminated Soil Dust and Slag, Objective c, -Prevent the
erosion of slag to the off-shore sediments". Existing data suggest the significance of
slag erosion is highly overestimated in the Proposed Plan. Although slag contains
elevated concentrations of total metals, available data show in the marine environment,
slag and sediment that contain slag have a very low teachability. In addition, no
detrimental effects of slag on sea life have been documented. In fact, the off-shore
community at the smelter is viable and healthy. Slag has been used on the plant site and
on the Yacht Club breakwater because its physical properties (coarse grain size and
massive texture) made the material an ideal medium for shoreline armoring construction.
Armoring of the slag would be primarily cosmetic with little, if any, benefit to the marine
environment. While slag armoring could provide a habitat niche for marine life, installation
of armoring will, at least temporarily, adversely affect presently established communities.
RESPONSE: EPA believes that slag is eroding to some degree, and therefore exposing
faces that leach metals more readily than weathered faces. As part of the remedial
3-7
-------
design, EPA will require that additional studies are conducted to indicate which part of
the slag shoreline is eroding and where shoreline armoring should be placed.
23. COMMENT: Page 11, Shoreline Armoring. This section appears to begin with the
premise that shoreline erosion is a substantive issue. Although shoreline armoring was
among alternatives evaluated in the FS, to date no information has been produced to
document that shoreline erosion is a substantial source of slag to the marine sediments
of Commencement Bay.
This question is raised for two reasons. Slag was directly placed in Commencement Bay
and its sediments by disposal actions over a 75-year period. Visually obvious erosion
could only account for a very small fraction of the slag present in Commencement Bay
sediments.
Erosion is visually obvious at some locations along the slag peninsula and smelter
property. However, many portions of this area show no obvious evidence of erosion.
This raises the question oif whether armoring the total shoreline is appropriate, or if
armoring is at all appropriate?
It is also reasonable to question whether slag erosion is causing any environmental
effects other than those produced by physical erosion of natural substrates. The study
of freshly cut slag by Battelle (Crecelius, 1986) showed that marine larvae settle as rapidly
on slag as on basalt rock and concrete. Although this study showed metals are released
from freshly cut slag for three to four months, this brief period would produce very minor
contributions of metals to Commencement Bay waters or sediments at the visually
apparent erosion rates.
The EPA discussion assumes that a 5 foot thick layer of riprap over a 2 foot layer of small
rock is necessary, to prevent erosion. Although total armoring for the shoreline was
assumed in alternatives presented in the FS, it will be necessary to conduct an
engineering analysis of shore processes along the smelter property and slag peninsula
to determine what design is most appropriate, as well as if and where protection might
be required.
The existing slope along the north portion of the bayward face of the slag peninsula may
be too steep to make armoring practical without major shoreline modification. The steep
slope at the north end of the Yacht Club breakwater extends to great depths (at least to
200 feet) indicating that major dredging or cut back at this location may be required to
establish a foundation for shoreline monitoring.
Combined plant site and breakwater shoreline armoring costs would be $6.2 million
dollars based on assumptions presented in the FS and cost projections presented in the
Proposed Plan. This expense would be incurred for primarily cosmetic alterations to the
shoreline and provide little environmental benefit. In fact, shoreline armoring will have a
significant impact on diverse and apparently healthy communities already established in
shoreline slag.
RESPONSE: EPA agrees that additional engineering studies are necessary to determine
the extent of shoreline armoring that will be needed in areas that are eroding. EPA does
3-8
-------
not believe that shoreline armoring will be conducted for cosmetic purposes only, but will
be placed in those areas which pose a threat to the off-shore environment.
24. COMMENT: Page 14, Plant Site Soils, 1c. It should be noted that, in many cases,
sampling results will not determine the feasible extent of excavation, but will provide
documentation on post-excavation conditions. Excavation in some areas, particularly in
the fine ore bins area and the copper refinery areas, will be limited by equipment
capabilities, and by limitations associated with high water table and high permeability
conditions.
RESPONSE: EPA recognizes that some materials in the source areas will not be able to
be excavated, see "Implementability" in Section 8.0. In addition, Asarco will be required
to confirm that all necessary source area excavation, as practicable, has been performed.
25. COMMENT: Page 14, Plant Site Soils, 1 d. In addition to demolition materials, some soil
contains coarse grained fractions that are greater than 2 inches in size. During pilot scale
testing, these sizes were simply screened out and were not treated. If treatment were to
be implemented on a large scale, these fractions would either have to be ground to a
finer size for incorporation in the treatment process, or disposed with demolition debris.
Either action involves an increase of material handling, processing and costs over those
associated with the soil fixation process activities demonstrated during the pilot scale
tests.
RESPONSE: EPA understands that there may be some additional costs associated with
a full-scale treatment project. However, treatment has not been selected in this ROD for
this Site.
26. COMMENT: Page 14, Plant Site Soils, 1e. Removal of the car tunnel was not included
in the primary remedial action scenarios evaluated during the FS and this action is not
included in the Proposed Plan cost estimates. The FS assumed removal of the car tunnel
and railroad tunnels as available options and responsibilities of the owners:
Tacoma/Ruston, and Burlington Northern railroad, respectively. Since the tunnel is
associated with seeps that have poor water quality, it is possible that concrete from the
tunnel, if removed, would require disposal as a hazardous waste. It is estimated that
removal of the tunnel, including demolition costs, would increase present cost estimates
as high as $2.2 million. Filling the tunnel may be more cost effective than demolition and
removal. In addition, the car tunnel is part of a unit construction with the rail tunnel which
would be impacted by removal of the car tunnel portion of the structure.
RESPONSE: The determination of whether the tunnel is removed or filled in will be made
during the design phase of the project. As noted in Section 9.0 of the ROD, the OCF will
be designed to allow for a limited amount of additional capacity in the event there is more
than the estimated 160,000 cubic yards of soil and more than the estimated 80,000 cubic
yards of demolition debris that requires disposal, see Section 9.1.2. EPA notes that
Paragraph 4 of the Agreement in Principle states that: "Asarco agrees to fill or remove
the existing tunnel..."
27. COMMENT: Page 15, 3a, use of fabric as marker. A marker would not be necessary
for most of the plant site to identify the base of an imported soil cap. The presence of
slag which has a very dark color and coarse grained texture that would be significantly
3-9
-------
different in color and texture from fill, and topsoil imported to the site would provide easy
identification when the base of the cap was penetrated. In addition, remaining man-made
features such as concrete slabs, foundation or pavement would also easily be identified
at the base of the cap.
Ruston soils would also easily be identified. These soils will be incorporated under a
drainage gravel layer which is, in turn, underlain by a clay layer. These distinctly different
soil types would be easily identified and would mark the locations of the base of imported
topsoil as well as the top of underlying Ruston residential soils.
RESPONSE: EPA agrees that a visual marker will not be necessary since the clay layer
will serve this function as clay will be located above the slag, building pads and
foundations and the Ruston/North Tacoma residential soils.
Asarco is incorrect in stating that the day layer will underlie the residential soils. The
residential soils will be used as a sub-base below the clay on the Site cap. Residential
soils can be placed in areas of the site not likely to be impacted by groundwater.
28. COMMENT: Page 16, Figure 3 (in Proposed Plan), Hazardous Waste On-Site
Containment Facility (OCF). The figure is not correct. The part of the cover that
includes a 1 foot layer, which underlies the filter material, would not consist of compacted
soil as shown in the figure but, instead, would consist of a drainage layer.
RESPONSE: In the cap, beneath the one foot of drainage material, there will be a fabric
liner and two feet of compacted soil above the waste material, see Figure 7-2.
29. Page 18, Surface Water, second paragraph, last sentence. As noted several times in
the FS, large scale treatment of surface water to consistently meet low standards
associated with arsenic and metal marine criteria may not be technically feasible. This
is particularly true for the relatively large flows (200 gpm or greater) associated with
surface water discharge from drainage areas above the plant site.
RESPONSE: EPA will evaluate the need for, and the feasibility of, surface water treatment
after the source control activities in the ROD are completed.
30. COMMENT: Page 18, Shore Line Armoring of the plant site and slag peninsula. "One
goal for the shoreline would be to restore aquatic habitat that would benefit eelgrass,
salmon and other sea life. Methods may include shoreline pull back and sloping,
development of pocket beaches, mudflats, vegetated shallows, and shoreline
irregularity." There is no evidence that shoreline armoring would provide any aquatic
habitat more suitable for marine biota than the existing stag surfaces. The armoring might
provide less suitable habitat because of the loss of physical irregularities that the slag
provides. Rock riprap provides a generally even, flat surface inhabited by fewer species
and number of organisms than the highly irregular surfaces of slag.
Neither slag nor shoreline armoring provide a suitable habitat for eelgrass. Shallow water
wave energies that require hard substrates (armoring) prevent eelgrass growth. Eelgrass
also requires slit to sand-gravel substrates, not hard surfaces. Salmon and other sea life
are capable of using the existing slag habitat, and are unlikely to benefit from shoreline
armoring.
3-10
-------
Development of pocket beaches, mudflats, shoreline pullback, etc., goes far beyond
shoreline armoring. These actions would require great modification of the existing
conditions and would result in environmental and economic costs far greater than
traditional shoreline armoring as presented in the Feasibility Study. Existing features that
have present or potential future economic or environmental value such as the off-shore
piers may not survive modifications associated with modifications of features as discussed
in EPA's plan. The additional economic costs are not factored in the costs presented in
the FS or in the Proposed Plan. Preliminary estimates to include features described in
the Proposed Plan as part of shoreline armoring indicate costs would be increased $6
million to $9 million above the $6.25 million presented in the, Proposed Plan for plant site
and shoreline armoring costs. Since, as noted above, the area is by nature not suited
for many of features such as mudflats, eelgrass, and pocket beaches, as well as shoreline
cut backs would involve significant alteration to existing conditions. For instance, off-
shore features such as breakwaters would probably be necessary to encourage
fine-grained environments that maintain features such as mudflats and eelgrass. presently
not possible in the relatively fast moving coarse grained deposition environment typical
to not only the Asarco Site but the adjacent gravel beach areas outside the plant site
off-shore area. Obviously, implementation of features that require such an alteration of
existing conditions would require considerable study as part of preliminary remedial
design efforts.
RESPONSE: The riprap itself is not expected to provide a more suitable habitat than the
slag; however, the armoring can be designed to have ledges or irregularities that are
more supportive of marine biota than the slag. These areas could be constructed with
gravel and on a more gentle slope than the slope of the present Site. A habitat
conducive to epibenthic species (organisms living on the sea floor) could be created,
which would, in turn, be beneficial to salmon.
EPA agrees that low-energy habitats would not likely persist along the Asarco shoreline.
However, a moderately active environment, such as a gravelly/sandy area conducive to
other types of aquatic species, may be able to be created off the Asarco Site. Although
on-site mitigation is a preference, a habitat that is conducive to eelgrass could be created
as part of an off-site mitigation effort.
EPA agrees that reducing the effects of the currents on the exposed face of the Asarco
Site would require extensive effort, including the use of groins or breakwaters. These
costs, which would be weighed against their benefits, are not part of the shoreline
armoring costs in the FS, but rather can be part of the mitigation costs since they would
benefit the mitigation efforts. These costs could also be weighed against their overall
benefit and/or be compared to other mitigation efforts with similar costs.
Shoreline pullback, sloping, and shoreline irregularity are possible at the Site and can be
part of the shoreline armoring and/or mitigation efforts. For example, shoreline armoring,
which is intended to reduce the erosion of slag, can be accomplished adjacent to an area
that is cut back and less shallow, which could be intended as part of a mitigation site.
The most appropriate habitats (e.g., those with the greatest chance of persistence) would
then be chosen for these various post-remediation environments. The associated costs
could be part of the shoreline armoring costs and the mitigation costs.
3-11
-------
EPA will consider the existing features on-site and the planned uses of the site in the
remedial design stage so as to ensure compatibility.
EPA acknowledges that much more about the sediments site will be learned from the
ongoing and upcoming expanded RI/FS activities, including a better understanding of the
amount of erosion at the site and potential disposal and mitigation sites.
31. COMMENT: Page 18, Shoreline armoring of the plant site and slag peninsula.
"Further, since armoring would adversely impact intertidal habitat of the shoreline,
mitigation and/or restoration measures would be necessary." The admission that
adverse impact to intertidal habitat would occur is evidence that the existing habitat has
substantial production and ecological value. Mitigation would apparently be required
because this productive habitat would be degraded by shoreline armoring. Why conduct
armoring unless the habitat would be degraded by shoreline armoring. Why conduct
armoring unless the habitat is to be improved by this action? If it is improved, why
require mitigation; isn't the action mitigation? Off-shore ecological impacts were noted
in the FS evaluation as well as in the EPA Proposed Plan. As off-shore studies by
Parametrix have shown, the area contains a diverse and productive environment that is
essentially the same as other coarse grained bottom areas that are not located near or
potentially impacted by existing or past smelter activities.
RESPONSE: EPA disagrees. EPA acknowledges that there is intertidal habitat that
currently occupies the slag face at the Site; however, sampling activities on the off-shore
sediment site provide evidence of adverse biological effects. The present expanded RI/FS
activities at the sediments site will help quantify the harmful effects at the site with respect
to the present communities and allow EPA to balance the benefits of armoring compared
to the impacts to existing habitat caused by armoring. EPA agrees that replacing one
community with a similar community is not a beneficial use of funds; however, if the
present off-shore biological community is shown to be impacted, a replacement
community and/or mitigation effort may be warranted.
32. COMMENT: Page 18, Item (9), Safety Measures, lining and covering truck beds.
Lining and covering truck beds probably would not be necessary for on-site activities.
Excavation in areas such as the arsenic kitchen area, the copper refinery area, or the fine
ore bins would not require such precautions. However, it is noted transportation across
public roads from areas such as the stack hill or the cooling pond may require some of
the safety precautions described in the Proposed Plan.
RESPONSE: If trucks are just moving from one location to another on-site, lining truck
beds would probably not be necessary. But lining of truck beds, and other safety
measures, will be required for transportation of waste off-site.
33. COMMENT: Page 19, Item 10 (b), guidelines to ensure disposal of dredged
sediments would not be preventive or hindered by development activities. Although
an OCF could be designed to hold shoreline sediments, additional steps, that have not
been completely evaluated, would be necessary to ensure compatibility with incorporation
into the OCF. Contrary to the sediment handling procedures anticipated with either use
on an OCF or treatment, off shore sediments would have to be dewatered, with
subsequent disposal and/or treatment of the decant water. If incorporated into a
treatment option for "upland" soils, marine sediments themselves would not require
3-12
-------
treatment as all testing indicates the leaching potential is very low and most samples had
teachable metal concentrations less than analytical limits. However, a key issue would
be the increase in size of the OOP "foot print" to hold marine sediments and the resulting
loss of available land area available for development. Vertical expansion limited by
physical constraints, as well as constraints imposed by proposed road development and
aesthetics and an increase of the loot print" would be necessary. In addition to land
needed for a larger foot print, more land area will be needed, at least temporarily, for
sediment dewatering during construction, which would also complicate remediation and
development logistics.
RESPONSE: EPA has decided not to dispose dredged sediments in the OCF. See the
response to Comment No. 28 in Section A above.
34. COMMENT: Page 21, Shoreline Armoring: "Shoreline armoring under the Preferred
Alternative is protective because it controls the erosion of the slag shoreline into
Commencement Bay*. It has not been demonstrated that all or most of the slag
shoreline is eroding into the bay or that slag erosion is detrimental to the biological
production at the smelter shoreline or slag peninsula.
RESPONSE: See the responses to Comment No. 43 in Section A above and Comment
No. 22 in this Section.
35. COMMENT: Page 22, Surface Water "EPA believes that it may be appropriate to
establish a mixing zone when establishing discharge limitations for surface water".
Asarco concurs a mixing zone would be appropriate.
RESPONSE: The language on mixing zone is included in the ROD, see Section 9.9.
regarding performance standards for surface water. The determination whether a mixing
zone is appropriate and, if so, the parameters of the mixing zone will be made during
remedial design.
36. COMMENT: Page 22, Mitigation/Restoration. The Proposed Plan states that mitigation
and restoration would be necessary to compensate for "impacts to wetlands" during the
cleanup. It is not clear which areas of the site EPA considers to be wetlands. During
discussions about remediation of the site, some, parties have taken the position that any
alternative which contemplates filling the cooling pond would need to comply with
mitigation standards under section 404 of the Clean Water Act. However, the cooling
pond is not a wetlands within the definition of "waters of the United States." and section
404 requirements do not apply to its modification during remediation. The Asarco pond
was part of a waste treatment system and qualifies for the specific exemption for
treatment ponds in 33 CFR §328.3 (a) (7). Consequently, to the extent that there may be
other regulated wetlands on the site, the specific areas of the site involved should be
specifically identified and should exclude the cooling pond.
RESPONSE: EPA agrees with Asarco's interpretation regulations that the cooling pond
is not a wetland. Other areas of the Site, however, may be wetlands. A wetlands
assessment will be required on the Site before remedial activities begin. If any wetlands
are identified that will be adversely impacted by remedial activities, the appropriate
mitigation measures will be required.
3-13
-------
37. COMMENT: Page 24, Surface Water, last sentence referring to surface water
treatment relative to long-term effectiveness and permanence. The long-term
effectiveness of surface water treatment is questionable if large volumes are necessary
to treat and discharge standards are extremely low. Volume control would be key to
successful implementation. Treatment would be an on-going operation that would require
periodic and relatively consistent maintenance. However, if lines are completely replaced
and a design cap is implemented as proposed by EPA, surface water treatment should
not be necessary to address sources from the plant site. In effect the treatment plant as
proposed by EPA would be addressing off-site sources of arsenic and metals.
RESPONSE: EPA agrees that replacing the surface water drainage system should
eliminate the need for surface water treatment. After cleanup activities under the ROD are
completed, EPA will determine whether surface water discharging into the bay meets the
remediation goals (see Section 9.9 of the ROD).
38. COMMENT: Page 24, Shoreline Armoring, Preferred Alternative, large rock and
boulder riprap instead of artificial beach nourishment as riprap has a better potential
to withstand current and wave action and remain in place compared to using smaller
pebbles under the artificial beach nourishment option." Contrary to EPA's position,
coastal engineering and design experts often promote beach nourishment over riprap
structures. The Army Corps of Engineers and others prefer, in many cases, to use beach
nourishment because it can provide better erosion/deposition control, than riprap design
features (Mark Lorane, Applied Coastal Science Inc., personal communication). This is
particularly true where a potential exists for riprap structures to result in changes in wave
and current patterns which result in unexpected and/or uncontrolled erosion or deposition
in adjacent unmodified areas.
RESPONSE: EPA recognizes that riprap structures should be constructed only when
necessary, and erosion from water flowing around the ends of the slope protection (e.g.,
breakwater) can cause erosion. The slope protection can be constructed in order to
minimize this type of erosion. The design characteristics for the Asarco Site, including
the choice of beach nourishment versus riprap structures, can be determined during
remedial design, when there is a better understanding of the wave action and current
energy at the site.
39. COMMENT: Page 25, Shoreline Armoring, "Slag pieces cause adverse impacts to sea
life in off-shore sediments." Adverse impacts of slag pieces to sea life have not been
demonstrated by EPA's own admission.
RESPONSE: EPA disagrees. A report published by Battelle (Crecelius, 1986) concluded
that metals released from freshly exposed slag are toxic to marine organisms for up to
three to four months. Also, one of the objectives of the expanded sediments RI/FS is to
evaluate whether slag pieces deposited in marine sediments are causing adverse impacts
in the marine environment.
40. COMMENT: Page 26, Interception Trench Costs. These costs should be rounded to
be consistent with other figures presented in this section.
RESPONSE: These numbers were rounded. See Table 8-2 in Section 8.0 of the ROD.
3-14
-------
41. COMMENT: Page 27, Surface Water Costs. On Page 24, EPA states use of surface
water treatment if necessary for plant site runoff surface water treatment costs are not
presented in the Proposed Plan. The FS presented surface water treatment costs for all
anticipated run-on to the site at $23,600,000, present value. EPA's proposal would only
address treatment after replacement of the present drainage system and implementation
of diversions as necessary. Assuming the majority of runoff is diverted, the EPA proposal
could require treatment of some undetermined volume. Even modest volumes of water
(50 to 100 gpm) requiring arsenic and metal treatment would result in a significant amount
of costs not presented in the plan. Asarco's experience at the East Helena Superfund
site, where a treatment plant was installed to address plant water gains of about 50 gpm,
shows costs to treat constituents similar to those at the Tacoma site are about
$7,000,000, However, if outfall drainage lines are completely replaced and a design cap
is implemented as proposed by EPA, surface water treatment should not be necessary
to address sources from the plant site. The treatment plant as proposed by EPA in effect
would be addressing off-site sources of arsenic and metals.
RESPONSE: The need for, and feasibility of, surface water treatment will be evaluated
should source control activities not attain performance standards for surface water.
42. COMMENT: Page 27, Shoreline Armoring Costs. Assuming riprap shoreline armoring
costs as presented in the FS, the costs presented in the Proposed Plan are consistent
with the FS. However, the costs do not reflect features discussed in the plan including
pocket beaches, mudflats, eel grass, cut backs etc. Preliminary cost projections
incorporating features as described in the Proposed Plan indicate shoreline armoring
costs could increase $6 million to $9 million over the cost presented in the Proposed
Plan. Four scenarios were considered:
1. Armoring as presented in the proposed plan.
2. Armoring assuming no encroachment in the bay and cut backs are necessary
prior to riprap installation.
3. Shoreline armoring with advancing slopes and groins, and silt/sand fills needed
to create vegetated shallows, pocket beaches and shoreline irregularities for
aquatic habitat development.
4. Same as Scenario 3 but all cut backs and no advancing features.
While it is assumed for cost estimation purposes that features described in the four
scenarios above could be implemented, it is far from certain incorporation of these
features is technically feasible. A summary of preliminary cost estimates for the armoring
scenarios is presented below:
3-15
-------
Proposed Plan Costs
#1
Plant site and Breakwater
Scenario # 2
Plant site and Breakwater
Scenario # 3
Plant site and Breakwater
Scenario # 4
Plant site and Breakwater
Capital
$5.9 million
Capital
$8-6 million
Capital
$1 1 .9 million
Capital
$14.6 million
O&M
$23,000
O&M
$24,000
O&M
$48,000
O&M
$48,000
Present Worth
$6,2 million
Present Worth
$9.0 million
Present Worth
$12.6 million
Present Worth
$15.4 million
RESPONSE: The costs associated with mitigation activities will be in addition to the
shoreline armoring costs. Mitigation costs can vary significantly, depending on the
location of the site, the necessary preparation activities, and size of the site. Because
EPA does not yet know the extent to which shoreline armoring will be required, EPA is
not estimating the potential cost of mitigation.
43. COMMENT: Page 27, Institutional Controls. The $500,000 under the 0 & M (annual)
column should be moved to the Present Worth column.
RESPONSE: This amount has been moved, see Table 8-2 in Section 8.0 of the ROD.
44. COMMENT: Page 27, Plant Site Excavation Costs. The excavation or demolition costs
presented do not include removal or filling of the car tunnel. As explained in the FS, this
option was presumed to be the responsibility of the owner. Removal of the tunnel would
increase costs an estimated $2.2 million.
RESPONSE: In Paragraph 4 of the Agreement in Principle, Asarco agreed to remove or
fill the car tunnel. EPA believes the approach to be used should be decided during
remedial design.
45. COMMENT: Page 29, first column - last sentence continuing to the second column.
This sentence is not comprehensible and needs revision.
RESPONSE: EPA corrected the error in subsequent editions of the Proposed Plan.
46. COMMENT: Page 30, (1) Statutory Findings, "cost effective." Asarco does not concur
that soil treatment is cost effective compared to other equally protective alternatives such
as containment in an OCF. EPA's preferred alternative is almost $30 million higher than
that proposed in the Agreement in Principle between Ruston, Tacoma, the Metropolitan
Park District and Asarco.
RESPONSE: EPA has determined in the ROD that disposal of soil and debris in an OCF
is a cost-effective cleanup action.
3-16
-------
APPENDIX B
FIGURES AND TABLES
-------
CO
Z
3 in 10
(3.0x1Cr1)
2.5 in 10 .
(2.5 X10'1)
2 in 10
(2.0 x1
1.5 in 10
(1.5 x10'
1 in 10
(1.0 x1
5 in 100
(5.0 x10'2)
KEY:
Figure B-1
CANCER RISK in ARSENIC KITCHEN AREA
(Area 2)
NON-USE
! I
INDUSTRIAL RECREATIONAL RESIDENTIAL
COMMERCIAL
LAND-USE SCENARIOS
BSOILINGESTION
mDERMAL
• INHALATION
m DRINKING
D EATING VEGETABLES
NOTE: Where the cumulative cancer risk on a site is greater than
approximately 1 in 10,000 (1 x 10-4), a cleanup is generally required.
B-1
-------
Figure B-2
NON-CANCER HAZARDS in ARSENIC KITCHEN
AREA (Area 2)
1200-
1000-
-» 800-
X
UJ
Q
g 600^
400-
200-
NON-USE COMMERCIAL INDUSTRIAL RECREATIONAL RESIDENTIAL
LAND-USE SCENARIOS
KEY.
SSOILINGESTION
MDERMAL
• INHALATION
g DRINKING
D EATING VEGETABLES
NOTE: Cleanup is generally required when significant health effects
are likely to occur (Hazard index is greater than 1.0)
B-2
-------
TABLE B-1. INFORMATION REPOSITORIES
In Ruston:
In Tacoma:
In Olympia:
In Seattle:
Ruston Town Hall
51 17 North Winnifred
Asarco Information Center
531 1 North Commercial
Tacoma Public Library Main Branch
1102 Tacoma Avenue South, Northwest Room
McCormich Regional Branch Library
3722 North 26th
City of Tacoma
747 Market Street, Suite 420
Tacoma Pierce County Health Department
3633 Pacific Avenue
Citizens for a Healthy Bay
771 Broadway
Pacific Lutheran University Library
121st and South Park Avenue
Washington Department of Ecology
300 Desmond Drive S.E.
Environmental Protection Agency
1200 Sixth Avenue
B-3
-------
TABLE B-2. UST OF FACT SHEETS AND BROCHURES FOR THE
ASARCO TACOMA SMELTER SITE
Date
9/86
10/86
4/87
8/87
3/88
5/88
7/88
8/88
12/16/88
4/27/89
5/11/89
7/14/89
9/89
2/90
5/8/90
7/16/90
8/90
1/14/91
Topic(s)
Fact sheet announcing an AOC between EPA and Asarco for an RI/FS, site
stabilization, and an announcement of a public meeting.
Fact sheet announced a public meeting on November 6, 1 986, for
concerned citizens to hear about the results of the exposure pathways
study for the Asarco Smelter.
Status Report published.
Status Report published.
Status Report published.
Status Report published.
Superfund update on the Asarco project.
Status Report published.
Fact sheet announced that EPA was to study arsenic contamination in the
Ruston area, evaluate who might be at risk, and decide what actions need
to be taken.
Fact sheet provided a status report of the smelter site RI/FS.
Fact sheet announced that EPA received the proposed work plan from
Asarco for demolition of the structures and of the smelter stack.
Fact sheet requested Asarco to conduct the investigation to determine the
extent of contamination at the smelter.
Update of all Superfund projects in Tacoma including information on the
Asarco Smelter, and EPA s invitation to residents to join a community
workgroup.
Update of all Superfund projects in Tacoma including a status report on
the Asarco Smelter.
Fact sheet announced a Notice of Violation issued to Asarco by EPA.
Fact sheet announced the public meeting and comment period for the
proposed plan for the initial site cleanup.
Update of all Superfund projects in Tacoma including a status report on
Asarco.
Fact sheet announced the plan for the interim cleanup measures. This
was the first ROD for the site.
B-4
-------
TABLE B-2. UST OF FACT SHEETS AND BROCHURES FOR THE ASARCO TACOMA
SMELTER SITE (Continued)
Date
2/13/91
5/6/1991
8/6/91
10/91
1/9/92
3/92
7/14/92
11/92
1/11/93
6/93
9/22/93
1/24/94
3/94
Topic(s)
Update of all Superfund projects in Tacoma including the Asarco Smelter
cleanup measures. This fact sheet also included information on EPA's
Community Workgroup and community interviews which were underway.
Fact sheet provided an update of all of the Asarco Superfund projects
including the status of the smelter investigation.
Update of all Superfund projects in Tacoma including the Asarco Smelter
interim measures (demolition) and the overall site investigation which now
includes Asarco sediments.
Brochure describina all of the Superfund activities related to the Asarco
Smelter including; the Ruston North Tacoma Study Area, the smelter site
investigation and demolition, and marine sediments.
Fact sheet announced the public meeting and comment period on EPA
and Asarco's efforts to demolish structures on the site, including the
smelter stack.
Update of all Superfund projects in Tacoma including the status of the
smelter demolition, disposal of the debris, collecting surface water on the
site, implementing controls to reduce the amount of surface water entering
the site, and an overall site investigation.
Fact sheet updated all of the Asarco Superfund projects.
Update of all Superfund projects in Tacoma including a status report on
the Asarco smelter.
Fact sheet updated all of the Asarco Superfund projects.
Update on all Superfund projects in Tacoma including the smelter
demolition and the overall site investigation.
Fact sheet announced the availability of the RI/FS and Risk Assessment
reports for the site.
Update on the hazardous waste cleanup project. EPA integrated the
smelter facility and the slag peninsula cleanup activities with the cleanup
for the off-shore sediments project.
Brochure (revision of 10/91 version) describing all of the Superfund
activities related to the Asarco Smelter including; the Ruston North Tacoma
Study Area, the smelter site investigation and demolition, and marine
sediments. This brochure continues to be available to members of the
community upon request, and is provided as a handout at all of EPA's
public forums.
B-5
-------
TABLE B-2. LIST OF FACT SHEETS AND BROCHURES FOR THE ASARCO TACOMA
SMELTER SITE (Continued)
Date
4/28/94
8/94
8/12/94
10/5/94
11/21/94
12/29/94
Topic(s)
Fact sheet described a field test of a soil treatment technology, which was
being considered for the Asarco Site.
Update on the hazardous waste cleanup projects in Tacoma, including the
Asarco demolition activities and the smelter cleanup.
Summary of EPA's Proposed Plan, announcement of public comment
period and public meetings.
Fact sheet announced EPA's proposal to allow slag to be moved from
Thome Road to the Asarco Smelter site. Public comments were invited
from October 6 to November 4, 1994.
Fact sheet announced Asarco was moving the slag from Thorne Road in
the Tacoma tideflats to the former Asarco Smelter in Ruston.
Fact sheet announced that alt buildings slated for removal have been
demolished and hazardous waste is being stored in the Fine Ore Bins
building.
B-6
-------
TABLE B-3. ARSENIC CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER
IN THE SOURCE AREAS
ARSENIC KITCHEN
Surface Soil
(ppm)
Max:
Mean:
Min:
33,225
16,174
2,020
Subsurface Soil
>1.5ft
(ppm)
Max:
Mean:
Min:
262,500
7,819
6.6
Class III GW
Slag
(H9/L)
Max:
N/A
Class III GW
Marine Sands
2.5ft
(Ppm)
Max:
Mean:
Min:
3,250
601
3.3
Subsurface Soil
>1.5ft
(ppm)
Max:
Mean:
Min:
3,150
363
1
Class III GW
Slag
(H9/L)
Max:
0.271
Class III GW
Marine Sands
(H9/L)
Max:
0.277
EPAGW
PRG
(ng/L)
6
STACK HILL
Class III GW
Slag
(ng/L)
Max:
N/A
Class III GW
Marine Sands
(ng/L)
Max:
95
COOLING POND
Subsurface Soil
>3 in
(ppm)
Max:
Mean:
Min:
3,025
402
0.18
Class III GW
Slag
(ug/L)
Max:
N/A
Class III GW
Marine Sands
(ng/L)
Max:
4.542
EPAGW
PRG
(lig/L)
6
EPAGW
PRG
(ug/t-)
6
B-7
-------
TABLE B-3. ARSENIC CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER
IN THE SOURCE AREAS (Continued)
FINE ORE BIN BUILDING
Surface Soil
(ppm)
Max:
Mean:
Min:
N/A
N/A
N/A
Surface Soil
(ppm)
Max:
Mean:
Min:
N/A
N/A
N/A
Subsurface Soil
>7tt
(ppm)
Max:
Mean:
Min:
1,180
643
8
Subsurface Soil
>5ft
(ppm)
Max:
Mean:
Min:
24,950
4,084
10
Class III GW
Slag
(ng/L)
Max:
31
Class III GW
Marine Sands
(ug/L)
Max:
2.8
EPAGW
PRG
(ng/L)
6
S.E. Plant Area
Class III GW
Slag
(ng/L)
Max:
51.69
Class III GW
Marine Sands
(H9/L)
Max:
1.5
EPAGW
PRG
(ng/L)
6
B-8
-------
TABLE B-4. COPPER CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER IN
THE SOURCE AREAS
ARSENIC KITCHEN
Surface Soil
(ppm)
Max:
Mean:
Min:
37,375
15,308
4,838
Subsurface Soil
>1.5ft
(ppm)
Max:
Mean:
Min:
53,250
2,669
8
Class III GW
Slag
(ng/L)
Max:
N/A
COPPER REFINERY
Surface Soil
(ppm)
Max:
Mean:
Min:
N/A
N/A
N/A
Surface Soil
(ppm)
Max:
Mean:
Min:
2,600
2,309
2,068
Subsurface Soil
>2.5ft
(ppm)
Max:
Mean:
Min:
16,700
2,159
29
Class III GW
Slag
(H9/L)
Max:
0.914
STACK HILL
Subsurface Soil
>1.5ft
(ppm)
Max:
Mean:
Min:
5,750
439
2
Class III GW
Slag
(ng/U)
Max:
N/A
Class III GW
Marine Sands
(ng/U
Max:
0.0051
Class III GW
Marine Sands
(ng/L)
Max:
2.8
EPAGW
PRG
(ng/L)
40
EPAGW
PRG
(ng/L)
40
Class III GW
Marine Sands
(ng/L)
Max:
33
EPAGW
PRG
(ng/L)
40
COOLING POND
Surface Soil
(ppm)
Max:
Mean:
Min:
341 ,250
59,423
201
Subsurface Soil
>3in
(ppm)
Max:
Mean:
Min:
1,250
122
0
Class III GW
Slag
(ng/L)
Max:
N/A
Class III GW
Marine Sands
(ng/L)
Max:
0.011
EPAGW
PRG
(ng/L)
40
B-9
-------
TABLE B-4. COPPER CONCENTRATIONS FOR SOIL AND CLASS III GROUND WATER IN
THE SOURCE AREAS (Continued)
FINE ORE BIN BUILDING
Surface Soil
(ppm)
Max:
Mean:
Min:
N/A
N/A
N/A
Subsurface Soil
>7ft
(ppm)
Max:
Mean:
Min:
1,980
1,230
60
Class III GW
Slag
(H9/L)
Max:
0.14
Class III GW
Marine Sands
(ng/L)
Max:
10.2
EPAGW
PRG
(ug/L)
40
S.E. PLANT AREA
Surface Soil
(ppm)
Max:
Mean:
Min:
N/A
N/A
N/A
Subsurface Soil
>5ft
(ppm)
Max:
Mean:
Min:
10,975
2,246
0.8
Class 111 GW
Slag
fofl/L)
Max:
0.122
Class III GW
Marine Sands
(H9/L)
Max:
0.008
EPAGW
PRG
(H9/L)
40
B-10
-------
TABLE B-5. REASONABLE MAXIMUM EXPOSURE ASSUMPTIONS
FOR RESIDENTIAL USE
Exposure
Group
Onsite
Residents
Offsite
Residential
Recreational
Visitor
Trespasser
Exposure
Route
inhalation
soil ingestion
slag ingestion
dermal*
leafy vegs.
root vegs.
water
inhalation
inhalation6
soil ingestion
slag ingestion
dermal3
fishc
inhalation6
soil ingestion
slag ingestion
dermal8
Age Group
(years)
0-30
0-6
6-30
0-61
6-301
0-6°
6-30°
0-6
6-30
0-6
6-30
0-6
6-30
0-30
0-30
0-30
0-6
6-30
0-6
6-30
0-6
6-30
0-30
6-30
6-30
6-30
6-30
Body Weight
(kg)
70
15
70
15
70
15
70
15
70
15
70
15
70
70
70
15
70
15
70
15
70
70
70
70
Contact Rate
20 m3/day
200 mg/day
100 mg/day
110 mg/day
55 mg/day
22.5 mg/day
11.25
mg/day
3900 mg/day
1900 mg/day
5000 mg/day
0.3 g/day
1.4g/day
1.5 g/day
2.5 g/day
2L/day
20 m3/day
90 mg/day
45 mg/day
90 mg/day
45 mg/day
12000
mg/day
1900 mg/day
5000 mg/day
45 mg/day
45 mg/day
1900 mg/day
5000 mg/day
Frequency
(days/years)
350
350
350
350
350
350
350
350
263
87
40
40
69
69
350
350
208, 52, 12
208, 52, 12
208
208
208, 52, 12
156, 39, 9
52, 13, 3
24
24
18
6
Duration
(years)
30
6
24
6
24
6
24
6
24
24
6
24
6
24
30
30
6
24
6
24
6
24
24
24
24
24
24
Skin area available for contact per day in cm2 is multiplied by a soil/skin adherence factor of 1.0 mg/mc2, giving units in
mg/day.
Evaluated qualitatively.
The fish pathway is evaluated by comparison of ground-water concentrations to ambient water quality criteria.
Indoor slag ingestion.
Outdoor slag ingestion.
B-11
-------
TABLE B-6. SLOPE FACTORS FOR CANCER-CAUSING CHEMICALS
CHEMICAL
Arsenic
Beryllium
Cadmium
Chromium VI
Lead
Nickel
PAHs8
PCBs
Aniline
EXPOSURE
ROUTE
Inhalation
Oral
Oral
Inhalation
Inhalation
Inhalation
Oral
Oral
Dermal
Oral'
CRITERIA
VALUE8
15°
1.75
4.3
6.3
42
0.84
7.3
7.7
9
0.0056
WEIGHT OF
EVIDENCE
CLASSb
A
A
B2
81
A
B2
A
B2
B2
B2
B2
TOXIC ENDPOINT
lung cancer
skin cancer
unspecified tumor locations by
injection
lung tumors
lung tumors
renal tumors in rate, no criteria values
set
lung cancer
stomach tumors
liver tumors
liver tumors
spleen and body cavity tumors in rats
SOURCE
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRISd
IRIS
IRIS
see text
IRIS
IRIS
a
b
c
d
e
Integrated Risk Information System, U.S. EPA (1993b).
Units (mg/kg/day)"1
Classification definitions: A - Human Carcinogen, sufficient evidence in humans.
B1 - Probable Human Carcinogen, limited human data available.
B2 - Probable Human Carcinogen, sufficient evidence in animals, inadequate or no evidence in humans.
C - Possible Human Carcinogen, limited animal evidence.
The IRIS Inhalation slope factor for arsenic is based on an administered dose from occupational exposure, see text.
IRIS lists a unit risk factor Is
-------
TABLE B-7. REFERENCE DOSES FOR NON-CANCER CAUSING CHEMICALS
CHEMICAL
Antimony
Arsenic
Beryllium
Cadmium
Chromium VI
Copper
Lead"
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
EXPOSURE
ROUTE
Oral
Oral
Oral
Oral
Dermal
Oral
Oral
Oral
Oral
Oral
Inhalation
Oral
Oral
Oral
Oral
Oral
RFD/RFC"
0.0004
0.0003-0.0008
0.005
0.0005 (water)
0.001 (food)
0.000025
0.005
0.04
500 mg/kg
0.005 (water)
0.14 (food)
0.0003
0.0003
0.02
0.005
0.005
0.00007
0.2
UNCERTAINTY
FACTOR
1000
3
100
10
10
500
1
1
1000
30
300
3
3
3000
10
RFD/RFC
CONFIDENCE
Low
Medium
Low
High
High
Low
Low
Medium/Low
Medium
Medium
High
Low
TOXIC ENDPOINT
reduced lifespan, altered cholesterol levels
hyperpigmentatlon, hyperkeratosis of skin
no adverse effects at this dose
proteins present in urine
proteins present In urine
no adverse effects at this dose
gastrointestinal irritation, flu-like disease
neurological and behavioral effect
central nervous system effects
central nervous system effects
kidney effects
neurotoxicHy
neonatal mortality, dermatological effects
selenium poisoning, biochemical alterations
skin discoloration
hair loss, possible liver effects
ANEMIA
SOURCE
IRIS
Glass &SAIC (1992)
IRIS
IRIS
IRIS
see text
IRIS
HEAST
U.S. EPA (1990e)
IRIS
IRIS
HEAST
HEAST
IRIS
IRIS
IRIS
HEAST
HEAST
IRIS Integrated Risk Information System, U.S. EPA (1S93b).
HEAST Health Effects Assessment Summary Tables, U.S. EPA (19924).
RtC Reference Concentration.
RID Reference Dose.
• Unites of Oral RfO are mg/kg/day; Units of Inhalation RfC are mg/m3, unless noted.
" Results of the uptake/bloklnetlc model (Glass and 3AIC, 1992) Is used to assess lead In soil for the residential scenario.
B-13
-------
TABLE B-8. ARARs ANALYSIS
The following requirements are applicable or relevant and appropriate requirements (ARARs) for the cleanup of the Asarco
Smelter.
ARARs
Summary
Comment
FEDERAL ARAB*
RCRA
40 U.S.C. § 6901 etseq
40 CFR Part 261
Identification and Listing of
Hazardous Waste
40 CFR Part 262
Standards applicable to Generators
of Hazardous Waste
40 CFR Part 264
Standards for Owners and Operators
of Hazardous Waste Treatment,
Storage, and Disposal Facilities
40 CFR I 264.18(b)
Location standard for floodplain
Subpart F: Release From Solid
Waste Management Units
Standards applicable In identifying solid wastes Involved in
site remedlations that are subject to regulation as
hazardous wastes.
These packaging and administrative requirements apply if
hazardous waste is shipped off-site.
Standards require that washouts from a 100-year flood be
prevented.
RCRA § 3001(b)(3)(A)(ii) and 56 FR 27300 exempt primary copper
smelter slag from RCRA. Therefore, RCRA Is not an ARAR for slag.
Other wastes on-site may be characteristic hazardous waste in which
case RCRA regulations are potential ARARs. There are no known
listed wastes on-site.
Pursuant to EPA's AOC policy, these requirements do not apply to
on-site movement of hazardous waste.
(55 Federal Register 8758, March 8, 1990).
The substantive standards detailed below are ARARs for the smelter
site remediation if on-slte treatment, disposal, or storage of hazardous
remediation waste takes place.
These requirements apply only to areas on-site deemed within a 100-
year floodplain.
The requirements of Subpart F are applicable to construction and
operation of an OCF.
B-14
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
40 CFR § 264.91
Required programs
40 CFR S 264.92
Groundwater protection standard
40 CFR 5 264.93
Hazardous constituents
40 CFR 5 264.94
Concentration limits
40 CFR S 264.95 - S 264.99
Monitoring requirements
Subpart G: Closure and Post-closure
40 CFR S 264.111
Closure performance standard
40 CFR S 264.114
Disposal or decontamination of
equipment, structures and soils
Substantive monitoring and response requirements may be
applicable if hazardous constituents are detected at points
of compliance.
Standard requires that the hazardous constituent limits are
not exceeded beyond the point of compliance In the
uppermost aquifer underlying the waste management area.
Standards by which EPA Identifies the hazardous
constituents to which the above groundwater protection
standard applies.
Concentration limits are set forth for the hazardous
constituents Identified under 40 CFR § 264.93.
Monitoring requirements are set forth to ensure compliance
and detect contamination.
A TSO facility must be closed in a manner which minimizes
the need for further maintenance and protects human
health and the environment.
All contaminated soils, equipment and structures must be
properly disposed of or decontaminated.
Subpart G ARARs are applicable to an OCF.
B-15
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
40 CFR §264.117
Post-closure care and use of
property
Subpart L: Waste Piles
40 CFR 8 264.2S1
Design and operating requirements
Subpart N: Landfills
40 CFR § 264.301
Design and operating requirements
40 CFR S 264.303
Monitoring and inspection
40 CFR S 264.310
Closure and post-closure care
40 CFR 8 26B
Land Disposal Restrictions
40 CFR S 268.35
Waste specific prohibitions third-third
wastes
Monitoring is required after closure is completed.
Requirements include protection from precipitation and
surface water run on, control of dispersal of waste by wind,
and no generation of leachate.
Landfill standards require liners and leachate collection
systems constructed of materials which provide sufficient
protectlveness of human health and the environment.
Monitoring of liner Integrity required.
Closure of a landfill requires a cover which minimizes
migration of liquids, functions with minimum maintenance,
and provides long-term integrity.
Contaminated soil and debris that are hazardous wastes
under RCRA are prohibited from off-site land disposal
unless treated pursuant to treatment standards.
The requirements of Subpart N are applicable to construction of an
OCF.
Monitoring and maintenance is required during the post-closure
period Identified by EPA.
Under the EPA AOC policy, Land Disposal Restrictions (LDRs) are not
applicable to disposal of remediation wastes within an area of
contamination. If contaminated soil and debris are disposed of off-
site, LDRs are applicable requirements.
B-16
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
40 CFR Part 268. Subpart D
Treatment Standards
40 CFR § 257.3
Criteria for classification of solid
waste disposal facilities and
practices.
40 CFR Part 257. Appendix I
CLEAN WATER ACT
33 U.S.C. §§ 1251 et.seq.
CWA §§ 303 and 304 (Federal Water
Quality Criteria)
33 U.S.C, 5 404 and 40 CFR Part 230
Discharge of Dredged or fill material
40 CFR § 122.26
Storm water discharges
Contaminated soil and debris shipped off-site for disposal
at a RCRA landfill must be treated before disposal.
A solid waste facility which disposes of non-hazardous
waste must meet the following criteria or it will be
considered an open dump and be prohibited under RCRA
§ 4004. A facility located in a floodplaln must not wash out
in the event of a flood. A facility must not Jeopardize
endangered species, violate ground water or surface water
quality standards or violate air quality standards.
The appendix sets forth MCLs for both organic and
Inorganic chemicals for use in determining compliance with
the ground-water criteria.
If soil and debris are shipped off-site to a RCRA TSD facility and LDR
treatment standards apply, a treatability variance may be necessary.
These requirements apply if non-hazardous wastes are disposed of
on-site.
Pursuant to CERCLA § 121(d)(2)(B)(i), otherwise non-
enforceable water quality criteria, developed by EPA for
surface water, are ARARs. Two kinds of water quality
criteria have been developed: one for protection of human
health, and another for protection of aquatic life.
Mitigation measures required for potential adverse impacts
to intertidal habitat or wetlands.
NPDES permit standards may apply If It Is determined that
stormwater discharge contributes to a violation of a water
quality standard or Is a significant contributor of pollutants
to waters of the U.S.
B-17
-------
TABLE B-S. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
40 CFR Part 125
• Subpart A
Criteria and Standards for Imposing
Technology-based Treatment
Requirements Under Sections 309(8)
and 402 of the Act
40 CFR Part 125
- Subpart K
40 CFR Part 125
- Subpart M
Ocean Discharge Criteria
40 CFR Part 6. App. A
Statement of Procedures on
Floodplaln Management and
Wetlands Protection
WASHINGTON INDIAN
(PUYALLUP1 LAND CLAIMS
SETTLEMENT
25 U.S.C. § 1773
Standards of control for direct dischargers must meet
technology-based requirements. Best conventional
pollution control technology (BCT) is applicable to
conventional pollutants. Best available technology
economically achievable (BAT) applies to toxic and non-
conventional pollutants.
Best management practices (BMPs) must be observed
when undertaking industrial activities which may result in
significant amounts of pollutants reaching surface waters.
Discharges to marine waters are permitted as long as the
discharge will not cause unreasonable degradation of the
marine environment.
Requires federal agencies to conduct its activities to avoid,
If possible, adverse impacts associated with the destruction
or modification of wetlands and occupation or modification
of floodplains.
Requires protection of fisheries through control of
discharges to Commencement Bay. Compliance with the
Settlement Act generally Is attained through compliance
with ARARs under federal or state law on discharges to
surface water.
For CERCLA sites, BCT/BAT requirements are determined on a case-
by-case basis using best professional judgment (BPJ).
BMPs are applicable to control the release of hazardous pollutants
Into surface waters during the smelter cleanup.
NPDES permit is not required if the discharge is within the site
boundaries, however, substantive requirements that would otherwise
be required under a permit are ARARs. A monitoring program may be
required to assess impact of a discharge. Such a requirement is
'relevant and appropriate*.
B-18
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
RIVERS AND HARBORS ACT OF
1899
33 U.S.C. § § 401 et seq.
33 U.S.C. 8 403
Obstruction of navigable waters
generally; wharves; piers, etc.;
excavation and filling-in
SAFE DRINKING WATER ACT
42 U.S.C. § § 300(f) at seq.
40 CFR Part 141
- SubpartB
Maximum Contaminant Levels
40 CFR Part 141
- Subpart F
Maximum Contaminant Level Goals
CLEAN AIR ACT
42 U.S.C. §§ 7401 et seq.
40 CFR Part 50
National Primary and Secondary
Ambient Air Quality Standards
Controls the alteration of the navigable waters (i.e., waters
subject to ebb and flow of the tide shoreward to the mean
high water mark). Activities controlled include construction
of structures such as piers, berms, and installation of
pilings.
Some minor activities may occur on-site along the shoreline during
remediation. No permit is required for on-site activities.
Maximum contaminant levels (MCLs) are enforceable
drinking water standards which are protective of human
health. The standards take into account available treatment
technology and cost.
Maximum contaminant level goals (MCLQs) are strictly
health-based goals for drinking water quality and are non-
enforceable. CERCLA § 121(d)(2) outlines use of MCLGs
in remedial actions (see also 55 FR 8750-53).
These regulations set forth the National Primary and
Secondary Ambient Air Quality Standards (NAAQS) which
were developed to protect the public health (allowing an
adequate margin of safety).
Some on-site remedial activities, such as handling contaminated s
and using an air stripper may be minor sources of air emissions.
B-19
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
ENDANGERED SPECIES ACT
16 U.S.C. §§ 1531 at seq.
MARINE MAMMAL PROTECTION
ACT
16 U.S.C. §§ 1361 at seq.
HAZARDOUS MATERIALS
TRANSPORTATION ACT
49 U.S.C. Ap. §§ 1801 et seq.
49 CFR Parts 171-177
U.S. Oept. of Transportation-
Subchapter C - Hazardous Materials
Regulations
NATIONAL HISTORIC
PRESERVATION ACT
16 U.S.C. S5 470 et seq.
ARCHEOLOGICAU AND
HISTORICAL PRESERVATION ACT
16 U.S.C. §§ 4699-1
STATE ARARS
Federal agencies must ensure that actions they authorize,
fund, or carry out are not likely to adversely modify or
destroy critical habitat of endangered or threatened
species.
EPA must ensure that its actions do not involve the
unauthorized taking of marine mammals.
Regulations provide for packaging, documentation, and
transport of hazardous waste.
These regulations are requirements lor any hazardous waste shipped
off-site for disposal during remediation.
This statute requires EPA to consider effects of remedial
actions on historic properties. (This evaluation was
conducted in connection with demolition activities.)
In the event that significant scientific, prehistorical, or
archaologica! data is present on a site, EPA must approve
the remedial activities so that such data is preserved.
The administrative procedural requirements, such as the Cultural
Resources Plan, are not ARARs.
The following state statutes and regulations are ARARs only if they
result in more stringent standards than those required under federal
statutes and regulations. (Requirements under federal programs that
a state is authorized to implement need not be more stringent.)
B-20
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
MODEL TOXICS CONTROL ACT
Chapter 70.105D ROW
WAG 173-340-360
Selection of cleanup actions
WAG 173-340-440
Institutional controls
WAG 173-340-705
Use of Method B
WAG 173-340-706
Use of Method C
Requires that cleanup actions, to the extent practicable,
comply with cleanup standards, use permanent solutions,
provide for reasonable time frames, minimize amount of
untreated hazardous substances, restore ground water, and
utilize long-term monitoring and institutional controls if on-
site disposal occurs.
These measures are undertaken to limit or prohibit activities
that may Interfere with the integrity of a containment area or
some other cleanup action.
Method 8 cleanup levels are potentially applicable to alt
sites. Standards must be at least as stringent as applicable
state and federal law and they must not result tn adverse
impact of aquatic and terrestrial life. For hazardous
substances for which sufficiently protective standards have
not been established, standards can be established by
estimations which result in no acute or chronic toxic effects
using a hazard quotient of (1); or for carcinogens,
concentrations with upper bound excess cancer risk of 1 X
106.
Method C cleanup levels may be established at
concentrations equal to background or at concentrations
which minimize overall threats if attainment of A or B levels
will increase the threat to human health and the
environment. These levels must be estimated by using a
hazard quotient of (1) and a 1 X 10"5 cancer risk for
carcinogens.
Administrative requirements in this section regarding a cleanup action
plan and public participation are not ARARs.
At this Site, Method B is applicable in setting cleanup levels.
B-21
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAC 173-340-707
Analytical considerations
WAC 173-340-708
Human health risk assessment
procedures
WAC 173-340-720
Ground water cleanup standards.
WAC 173-340-730
Surface water cleanup standards
When the cleanup level Is below the practical quantitation
limit (POL), the POL will become the standard as long as It
Is not greater than 10X the method detection limit.
This section sets forth the risk assessment framework
utilized to establish cleanup standards.
This section sets forth guidelines for ground water cleanup
levels, points of compliance, and the ground water
classification system. Ground water cleanup levels are
based upon the highest beneficial use (I.e. drinking water)
unless the ground water is not a potential source due to
high concentrations of dissolved solids or insufficient yield.
Further, If there Is an extremely low probability that the
ground water will be a future source of drinking water, the
cleanup levels may be based on protection of nearby
surface water.
Method A cleanup levels are based on the state and federal
water quality criteria. Method B cleanup levels require
compliance with these criteria unless It can be shown that
they are not relevant to the specific water body. Also
cleanup levels that are estimated must result in no acute or
chronic effects on fish or shellfish and a cancer risk less
than or equal to 1 x 10'6. Less stringent Method C levels
may be used if consistent with applicable laws, all
practicable methods of treatment are utilized, and
institutional controls are implemented. This section also
sets forth points of compliance and requires compliance
monitoring.
Methodologies for determining background concentrations are
potential ARARs.
At this Site, Method B is applicable to discharges to surface water.
B-22
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAC 173-340-740
Soil cleanup standards
WAG 173-340-745
Soil cleanup standards for industrial
sites
WAC 173-340-750
Cleanup standards to protect air
quality
WATER POLLUTION CONTROL
WAC 173-201-035
General considerations
This section sets forth residential cleanup levels. For sites
undergoing routine cleanup, Table 2, in this section, sets
forth applicable standards. Method B allows cleanup
standards not already established, to be calculated using
concentrations that will not result In toxic effects,
contamination ol ground water, or a cancer risk that Is no
greater than 1 X 10 8.
Industrial cleanup levels are less stringent than those set
for residential areas. To be classified as an industrial site,
the following criteria must be satisfied: the site is zoned
Industrial use; site was historically used for Industrial
purposes; adjacent property Is currently used or designated
industrial; the site will be zoned Industrial for the
foreseeable future; and the cleanup action provides for
institutional controls. An amendment to state law provides
that industrial properties include properties that are or have
been characterized by or committed to traditional Industrial
uses.
Removal and containment measures which release
hazardous substances to the air must be conducted In
accordance with air standards. Residential standards are
most stringent. Industrial standards may be established on
a case-by-case basis as long as concentrations .result In no
toxic effects and cancer risk Is no greater than 1 X 10 5.
Guidelines are set forth which apply to water quality criteria
and classifications such as the antldegredation policy and
criteria for short-term modification of water quality
standards.
B-23
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-201-045
General water use and criteria
classes
WAG 173-201-047
Toxic substances
WAC 173-216-060
Prohibited Discharges
WAC 173-220-120
Prohibited discharges
WAC 173-220-130
Effluent limitations, water quality
standards, and other requirements
and/or permits
WAC 173-220-210
Monitoring, recording and reporting
Chapter 173-240 WAC
Submission of Plans and Reports for
Construction of Wastewater Facilities
This section sets forth water quality criteria for each type of
water classification. Criteria considered includes fecal
coliform, dissolved oxygen, dissolved gas, temperature, pH,
turbidity, toxics, and aesthetics.
Water quality standards (fresh and marine water) are set
forth for several substances deemed toxic. Such
substances may not be introduced above natural
background if they adversely affect characteristic water
uses, public health, or cause acute or chronic conditions.
Discharges to a municipal sewage system must not
interfere with the system's operation.
Prohibits specific discharges Into waters of the state such
as pollutants that impair anchorage and navigation, and
toxic pollutants prohibited under CWA § 307.
This section sets forth substantive requirements for NPDES
permits such as effluent limitations based on known,
available, and reasonable methods of treatment. Effluent
limitations may be more stringent than those standards
developed under the CWA when necessary to meet water
quality standards.
Monitoring is required to ensure that discharges comply
with effluent limitations.
Construction requirements are set forth for wastewater
facilities.
Recording and reporting requirements in this section are
administrative and, therefore, are not ARARs.
The engineering report and plan requirements in this section are
administrative and, therefore, are not ARARs.
B-24
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
POLLUTION DISCLOSURE ACT OF
1971
Chapter 90.52 RCW
ROW 90.52.040
Wastes to be provided with available
methods of treatment prior to
discharge into waters of the State.
RCW 90.54.020
Qeneral declaration of fundamentals
for utilization and management of
waters of the state.
CONSTRUCTION PROJECTS IN
STATE WATERS
Chapter 220-110WAC
Hydraulic Code Rules
WELLWATER CONSTRUCTION
Chapter 18.104 RCW
WAG 173-160. Part 1
General requirements
Regardless of water quality and minimum water quality
standards, all wastes must undergo all known, available,
and reasonable methods of treatment prior to discharge,
except as provided below.
Regardless of water quality, all discharges to the waters of
the state must be provided with all known, available, and
reasonable methods of treatment, except where overriding
considerations of the public interest will be served.
Requirements are set forth for construction projects along
waterways, such as bulkhead construction and piling
installation, that are designed to protect marine life.
A hydraulic project approval Is not required since It Is a type of
administrative permit.
Requirements are set forth which pertain to design and
construction of wells generally; such as preservation of
natural barriers to prevent water flow between aquifers and
permanent sealing.
Permit requirements and other administrative provisions in this
section are not ARARs.
B-25
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-160. Part3
Resource protection wells
UNDERGROUND INJECTION
CONTROL PROGRAMS
Chapter 173-218 WAG
HAZARDOUS WASTE
MANAGEMENT ACT
Chapter 70.105A RCW
WAG 173-303-016
Identifying solid waste.
WAG 173-303-020
Applicability
WAG 173-303-060
Notification and Identification
numbers
WAG 173-303-070
Designation of dangerous waste
Specific design and construction requirements are set forth
for the drilling and use of monitoring and observation wells.
This program requires that injection wells not adversely
affect the beneficial use of an underground source of
drinking water.
This statute provides statutory authority for the Dangerous
Waste Regulations (DW) described below.
Guidelines are set forth which identify solid wastes that are
also dangerous wastes.
Dangerous waste regulations apply to generators,
transporters, and owners and operators of TSD facilities.
An ID# is required if any dangerous waste is shipped off-
site.
Procedure for determining whether or not a solid waste is a
dangerous waste (DW) or an extremely hazardous waste
(EHW).
If an injection well Is utilized on the smelter site it will be used to
inject salt water for treatment purposes and will not adversely affect
existing groundwater. These wells would be considered Class V wells
that do not inject waste fluids.
According to the State's Area of Contamination (AOC) Policy, the
movement of DW within an area of contamination is not considered
generation. Therefore, the DW regulations are not automatically
triggered but may be relevant and appropriate. Similarly,
containment, treatment, and disposal of consolidated wastes within an
AOC does not automatically trigger the DW regulations.
(Interprogram Policy dated September 6,1991).
Not an ARAR for on-site movement of wastes.
B-26
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAC 173-303-071
Excluded categories of waste.
WAG 173-303-081
Discarded chemical products.
WAG 173-303-082
Dangerous waste sources.
WAC 173-303-084
Dangerous waste mixtures.
WAC 173-303-090
Dangerous waste characteristics
WAC 173-303-100
Dangerous waste criteria.
Certain categories of waste may be excluded from the
requirements of the dangerous waste regulations. For
example, under subsection (3)(I), PCS waste whose
disposal is regulated pursuant to 40 CFR § 761.60 is
exempt from most DW regulations.
A waste is designated a DW if It Is a residue from
management of chemicals listed on the Discarded
Chemical Products List at WAC 173-303-9903.
All wastes or residues from wastes listed on the Dangerous
Waste Sources List are to be designated either DW or EHW
depending on the circumstances.
A waste mixture that has not been designated a DW must
be evaluated to determine whether or not toxic constituents,
specific hydrocarbons, or carcinogens are present. If
present in sufficient quantities, they are to be treated as
DW.
If a waste has characteristics of Ignttabllity, corrosivity,
reactivity, or toxicity, it could be designated a DW.
If a person has established that his waste meets the OW
criteria, he is a generator and must comply with appropriate
DW regulations for generators.
This requirement applies only to those DW which are transported off-
site.
B-27
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-303-101
Toxic dangerous wastes.
WAG 173-303-102
Persistent dangerous wastes.
WAG 173-303-103
Carcinogenic dangerous waste.
WAG 173-303-104
Generic dangerous wastes.
WAC 173-303-120
Recycled, reclaimed, and recovered
wastes,
WAC 173-303-140
Land disposal restrictions
WAC 173-303-141
Treatment, storage, or disposal of
dangerous waste.
WAC 173-303-150
Division, dilution, and accumulation.
Methods are set forth for determining the toxlclty of waste
and whether it Is a OW or EHW.
Procedure is set forth to designate wastes that contain
halogenated hydrocarbons and/or polycyclic aromatic
hydrocarbons with more than three rings and less than
seven rings (PAHs) as either DW or EHW.
Method lor designating a waste as carcinogenic.
Sets forth the DW number for each of the DW criteria
designations.
Exempts some recycled DW from the DW regulations if it
does not pose a threat to public health and the
environment. For example, scrap metal Is exempt from DW
regulations.
May require some type of treatment of DW prior to off-site
disposal. Treatment of EHW may be required prior to on-
site disposal if practicable.
DW shipped off-site for disposal must be shipped to a
properly permitted TSD facility.
The intent of the DW regulations may not be evaded by
dividing or diluting wastes.
This requirement Is only relevant for wastes shipped off-site for
disposal.
Pursuant to the State's Area of Contamination Policy, the State LDRs
are not applicable unless DW is shipped off-site for disposal.
Ecology and EPA have agreed to jointly decide the extent of
treatment necessary prior to on-site or off-site disposal of EHW.
On-site disposal of DW is subject to the state's AOC policy.
B-28
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-303-160
Containers.
WAC 173-303-161
Overpacked containers (labpacks).
WAC 173-303-180
Manifest.
WAC 173-303-270
Discharge during transport.
WAC 173-303-283
Performance standards.
WAC 173-303-550
Special requirements for facilities
managing special waste.
WAC 173-303-560
Minimum standards for facilities
managing special waste.
Applicable procedure for measuring waste quantity when
containers are utilized for shipment of DW off-site.
Requirements for overpacked drums such as use of non-
leaking Inside containers and use of non-reactive material
for shipping of DW off-site.
Manifesting is required when DW is generated.
Notification requirements apply if a transporter spills DW
during transport.
A DW facility must be designed and constructed, to the
maximum extent practical, to prevent: degradation of
ground water quality and air quality, destruction of flora
and fauna, excessive noise, negative aesthetic impact,
unstable hillsides, and endangerment of employees,
Processes used must treat, detoxify, recycle, reclaim, and
recover waste material to the extent economically feasible.
Guidelines by which Ecology will approve less stringent
standards for facilities which handle 'special wastes'.
Minimum standards are set forth which Ecology may
approve for 'special waste' facilities.
Manifesting required only if DW is transported off-site.
These requirements apply only In the event of a spill during
transportation of DW off-site.
Special wastes are those that are not considered hazardous wastes
under RCRA but are designated a DW under the more stringent state
standards.
B-29
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-303-600
Final facility standards.
WAC 173-303-610
Closure and postclosura.
WAC 173-303-645
Releases from solid waste
management units.
WAC 173-303-660
Waste Piles
WAC 173-303-665
Landfills.
WAC 173-303-9903
Discarded chemical products list.
This section specifies which TSD facilities are subject to
closure requirements.
Closure and performance standards require that a facility
be closed to minimize need for further maintenance and
control, minimize, or eliminate the escape of OW to the
environment. The land must also be returned to the
appearance and use of surrounding land to the degree
possible. All contaminated soils, equipment, and structure
must be disposed of properly. Notice of disposal of waste
must be recorded on the deed.
This section sets forth ground-water monitoring
requirements for postclosure periods for facilities that are
closed without all DW removed. Criteria Is listed by which
dangerous constituents are identified and concentration
limits are determined. Such requirements are "relevant and
appropriate.'
Requirements for temporary storage of dangerous waste,
e.g., protection from precipitation.
Landfills must be constructed with a liner and teachate
collection system. There must be systems to control run-on
and run-off. Upon closure, the landfill must be covered
with final cover that provides long-term integrity.
Lists of chemicals which are designated as either EHW or
DW.
Survey plats, closure plan and certificate requirements in this section
are administrative and, thus, are not ARARs. Monitoring to ensure
closure integrity is required. Such a requirement Is 'relevant and
appropriate.'
B-30
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-303-9904
Dangerous waste sources list.
WAG 173-303-9905
Dangerous waste constituents list.
WAG 173-303-9906
Toxic dangerous waste mixtures
graph.
WAG 173-303-9907
Persistent dangerous waste mixtures
graph.
Solid Watte Management
Reduction and Recycling
Chapter 70.95 RWC
WAG 173-304-130
Location Standards for Disposal
Sites.
WAG 173-304-407
General closure and post-closure
requirements.
All wastes listed are designated as DW.
List of chemically distinct components of a dangerous
waste stream or mixture,
Graph Is utilized to determine whether a mixture containing
toxics is either a DW or EHW.
Graph is utilized to determine whether wastes containing
certain percentages of persistent DW constituents are DW
or EHW.
This section sets forth locatlonal standards regulating
proximity of facilities to faults, groundwater, surface water
and floodplalns.
Closure performance standards are set forth which require
that the need for further maintenance be minimized and
threats to human health and the environment be controlled
or eliminated.
The closure and post-closure plan requirements and other
administrative procedures In this section are not ARARs.
B-31
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Comment
WAG 173-304-460
Landfilling standards.
WAG 173-304-461
Inert waste and demolition waste
landfilling facility requirements.
WAG 173-304-490
Groundwater Monitoring
Requirements.
SHORELINE MANAGEMENT ACT
OF 1971
Chapter 90.58 RCW
These standards do not apply to inert wastes and
demolition wastes but they do apply to problem wastes.
Minimum functional standards require that landfills not
contaminate ground water or surface water. A leachate
collection system and liner is required. Also facilities
located In floodplains must not restrict the flow of the base
flood. Water run-on and run-off must be controlled. Also,
dangerous waste disposal Is prohibited In a solid waste
landfill.
This section requires that fugitive dust be controlled, that
combustible waste be covered to avoid a fire hazard, and
that the site be leveled to the extent practicable at closure.
Monitoring is required to ensure that groundwater quality is
not affected by disposal site.
Local shoreline master programs may set out substantive
requirements that apply to construction activities within 200
feet of the shoreline.
The documentation requirements such as operating plans are
administrative and, therefore, are not ARARs.
The permitting requirement and other documentation requirements in
this section are administrative and, therefore, are not ARARs.
This requirement is 'relevant and appropriate.'
Permitting requirements are not ARARs for on-site construction
activities.
B-32
-------
TABLE B-8. ARARs ANALYSIS (Continued)
ARARs
Summary
Commont
WASHINGTON CLEAN AIR ACT
Chapter 70.94 RCW
WAG 173-400-040
General standards for maximum
emissions
WAG 173-460
Controls For New Sources of Toxic
Air Pollutants
PSAPCA REGULATION 1
Section 9.15
Fugitive Dust: Emission Standard
All 'emission units' (i.e. any activity that emits contaminants
to air) are required to use reasonably available control
technology. Emissions must not violate opacity standards
or cause participate matter to deposit on adjacent property
which Interferes with Its enjoyment. Further, reasonable
precautions must be taken to prevent fugitive emissions
and dust and to reduce odors. No emission is permitted
that causes detriment to health, safety, and welfare of any
person.
An acceptable source impact level is set forth for arsenic.
This standard may be an applicable and relevant
requirement during the construction phase of the
remediation.
Best available control technology must be used to control
fugitive emissions. Oust emissions are prohibited if they
are injurious to human health, plant or animal life or
interfere with enjoyment of property.
B-33
-------
APPENDIX C
SUMMARY OF ADDITIONAL SOIL TREATABIUTY PILOT-PROJECT FINDINGS
-------
PILOT SCALE TREATABBLITY TESTING
OF PLANT SITE SOILS AT THE ASARCO TACOMA SMELTER
ANALYTICAL SUMMARY SUPPLEMENT
Prepared for:
Mr. Thomas L. Aldrich
Plant Site Manager
ASARCO Incorporated
P.O. Box 1677
Tacoma, WA 98401
Prepared by:
Hydrometrics, Inc.
2727 Airport Rd.
Helena, MT 59601
December 1994
-------
5.0 SUMMARY
As outlined in the Pilot Scale Treatability Sampling and Analysis Plan, specific
objectives of the pilot scale testing project included:
1. establish an analytical testing program to assess the effectiveness of the
treatment in reducing contaminant leachability:
2. optimize additive mix proportions so as to provide lowest cost treatment
which meets or exceeds preliminary remediation goals;
3. evaluate sensitivity of treatment effectiveness to variations in feed material
quality;
4. refine process operating ranges and monitoring procedures to assure
consistent performance during full scale operation.
Extensive chemical and physical tests have been performed to characterize the
effectiveness of the treatment method in reducing contaminant leachability. Leach test
results on field control lot samples and laboratory compaction samples suggest that the
ARCHON solidification/stabilization process successfully immobilized contaminants,
resulting in undetectable or low teachable concentrations of Ag, As, Cd, Cu, Ni, Pb, Sb,
Se, Tl, and Zn. This reduction in leachability was maintained for all treatment mixes,
independently of any-variations in pre-treatment soil feed or treatment mix percentages.
Physical parameter test results were less conclusive, as physical tests performed on
sample molds are apparently not completely representative of actual large scale post-
treatment physical properties. Differences in heat generation/retention and associated
curing processes are believed to cause observed differences in percent volume change
calculations, and may also result in differences between laboratory and field values of
028VX)2V)104UiELX3SSA94l2U\H.-028\SUMRI>RTJX)C 34
-------
permeability, and/or compressive strength. Although tests conducted may provide some
insight on the physical characteristics of post-treatment soil samples, it should be noted
that conditions in the field are likely to be different than those implied by mold test
results.
028\D02V3104\HBX»SS\941214\R<)28\SUMRPRT.DOC 35
-------
APPENDIX D
ASARCO SMELTER SITE ON-SITE CONTAINMENT FACILITY EVALUATION
-------
Reply to
Attn of:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 10
1200 Sixth Avenue
Seattle, Washington 98101
HW-106
FEB 2 * 1995
MEMORANDUM
SUBJECT: Asarco Smelter Site
On-site Containment
Facility (OCF)
FROM: Catherine Massimino£$[_
Senior RCRA/Superfund
Technical Specialist
TO: Piper Peterson
Regional Project Manager
SF Management - II
This is in response to your request for assistance in
reviewing the impact of treatment of 15% of the contaminated
soils prior to placement in a landfill at the Asarco Smelter Site
in Tacoma, Washington.
An evaluation of potential percolation from an on-site
containment facility (OCF) located in the central area of the
Asarco site as shown on Figure 6-3-6, of Asarco's Smelter Site
January 1993, Remedial Investigation Report (RI), was performed.
This evaluation bracketed an expected design scenario meeting
RCRA landfill standards (hereafter referred to as Scenario A-OCF
Good Cap and Liner), and a scenario reflective of long-term
deterioration Scenario A of the OCF (hereafter referred to as
Scenario B-OCF Poor Cap and No Liner). Both scenarios reflected
25 feet of waste and a landfill surface area of 18 acres. This
will accommodate two (2) feet of contaminated soil in addition to
the amount that Asarco had approximated on Exhibit A5-3-2 Volume
4-Appendices Asarco Tacoma Plant Feasibility Study (FS) of its
conceptual OCF design as necessary to accommodate 240/000 cubic
yards of wastes. This additional two (2) feet of waste should
allow about a 10% safety factor for waste volume.
This review was performed utilizing the Hydrologic
Evaluation of Landfill Performance (HELP) model Version 3.01
The OCF Good Cap and Liner configuration and layers modeled in
this review are very similar to the scenario evaluated by Asarco
under Appendix 5-2b of Volume 4 of the FS with the following
major exceptions: a) used model synthetically generated
precipitation data from Olympia, refined to include monthly
precipitation data from Seattle-Tacoma International Airport
instead of 20 years of historic daily precipitation data from
Printed on Recycled Paper
-------
Seattle-Tacoma International Airport, a waste layer depth of 25
feet versus 30 feet, a surface area of 18 acres, including OCF
liner and cap components versus 10.5 acres, which including only
the contaminated soil, SCS runoff curve number was computed by
the model, input of leakage fraction for the flexible membrane
liner (FML) was replaced by factoring into the model values
reflective of good quality for pinhole density, installation
defects and overall placement quality, and the model was run for
100 years versus 20. The detailed model inputs and outputs can
be found in Attachment 1 to this memorandum.
The major differences in input values for the two scenarios
can found on Table 1. The largest difference being the
assumption for the Poor Cap and No Liner Scenario B that the
bottom liner has so deteriorated that it is no longer functioning
as a liner and the percolation being evaluated is from the bottom
of the waste. The results of this modeling are summarized in
Table 2.
The above HELP modeling results were utilized to estimate
contaminate loading from the OCF into Commencement Bay without
any pretreatment of the contaminated soils and with 15% of the
contaminated soils pretreated. Based on this comparison, which
is presented in Table 3, the difference between the arsenic
loading from the OCF Scenario B (worst case percolation) of 106
grams per day, when none of the waste is treated versus 15%
treated of 90 grams per day, is very minimal. Based on this
evaluation, treatment of 15% of the waste can not be justified.
As the HELP model is designed to be a comparative evaluation tool
this data is not appropriate for use in performing an evaluation
of the impact of this loading to Commencement Bay. In addition,
it should be noted that this loading comparative determination
did not account for dilution or absorption in the soil column of
the contaminant during the travel of the percolation out of the
OCF to Commencement Bay.
-------
•FABLE 1
HELP MODEL MAJOR INPUT VALUE DIFFERENCES BETWEEN SCENARIOS A & B
INPUT VALUES
Hydraulic
conductivity of
low permeability
soil layer in cap
FML
Pinhole density
Installation
defects
Placement Quality
SCS Runoff Curve #
Maximum Leaf Area
Index
Bottom Liner System
A. OCF GOOD CAP
AND LINER
1 X 10-7 cm/ sec
.75 holes/acre
2.0 holes/acre
Good
50.40 based on a
good stand of grass
3.5 based on a good
stand of grass
Leachate Collection
and Removal System
FML
Low permeability
soil layer
Leak Detection
Collection and
Removal System
FML
Low permeability
soil layer
B. OCF POOR CAP AND
NO LINER
1.2 X 10-6 cm/ sec
1 hole/ acre
15 holes/acre
Poor
74.40 based on a
poor stand of grass
1.0 based on a poor
stand of grass
No functional
bottom liner system
-------
TABLE 2
HELP MODELING AVERAGE ANNUAL PERCOLATION RESULTS
OCF SCENARIO
A. OCF GOOD CAP
AND LINER
B. OCF POOR CAP
AND NO LINER
CUBIC FEET/YEAR
.2
59,176
CUBIC FEET/DAY
0
162
TABLE 3
ARSENIC CONTAMINATION LOADING TO WATERWAY
LOADING SCENARIO
LOADING TO WATERWAY
(GRAMS/DAY)
OCF SCENARIO B
0% TREATMENT
ARSENIC 23 PPM (TCLP)1
(UNTREATED) _•
106
OCF SCENARIO B
15% TREATMENT
ARSENIC 23 PPM (TCLP)1
(UNTREATED)
ARSENIC >5.0 PPM (TCLP)
(MINIMUM ACCEPTABLE
TREATMENT)
93
OCF SCENARIO B
15% TREATMENT
ARSENIC 23 PPM (TCLP)1
(UNTREATED)
ARSENIC .07 PPM (TCLP)1
(LOWEST TREATMENT LEVEL
ACHIEVED)
90
1.Pilot Scale Treatability Testing of Plant Site Soils at the
Asarco Tacoma Smelter, December 1994.
-------
ATTACHMENT 1
OCF HELP MODEL INPUTS AND OUTPUTS
-------
#* **
• **
"*** HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE **
** HELP MODEL VERSION 3.01 (14 OCTOBER 1994) **
** DEVELOPED BY ENVIRONMENTAL LABORATORY **
** USAE WATERWAYS EXPERIMENT STATION **
. ** FOR USEPA RISK REDUCTION ENGINEERING LABORATORY **
** **
** **
PRECIPITATION DATA FILE: c:\help3\asarl.D4
TEMPERATURE DATA FILE: c:\help3\ASAR2.D7
SOLAR RADIATION DATA FILE: c:\help3\ASAR3.D13
EVAPOTRANSPIRATION DATA: c:\help3\ASAR4.Dll
SOIL AND DESIGN DATA FILE: c:\help3\asar5.D10
OUTPUT DATA FILE: c:\help3\asar7.0UT
TIME: 9: 5 DATE: 2/23/1995
TITLE: ASARCO OCF-GOOD CAP AND LINER
NOTE: INITIAL MOISTURE CONTENT OF THE LAYERS AND SNOW WATER WERE
COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM.
LAYER 1
TYPE 1 - VERTICAL PERCOLATION LAYER
MATERIAL TEXTURE NUMBER 4
THICKNESS = 24.00 INCHES
POROSITY = 0.4370 VOL/VOL
FIELD CAPACITY = 0.1050 VOL/VOL
WILTING POINT = 0.0470 VOL/VOL
INITIAL SOIL WATER CONTENT « 0.3896 VOL/VOL
EFFECTIVE SAT. HYD. COND. - 0.170000002000E-02 CM/SEC
NOTE: SATURATED HYDRAULIC CONDUCTIVITY IS MULTIPLIED BY 4.63
FOR ROOT CHANNELS IN TOP HALF OF EVAPORATIVE ZONE.
-------
LAYER 2
TYPE 2 - LATERAL DRAINAGE LAYER
MATERIAL TEXTURE NUMBER 1
THICKNESS = 12.00 INCHES
POROSITY = 0.4170 VOL/VOL
FIELD CAPACITY - 0.0450 VOL/VOL
WILTING POINT - 0.0180 VOL/VOL
INITIAL SOIL WATER CONTENT - 0.4170 VOL/VOL
EFFECTIVE SAT. HYD. COND. = 0.999999978000E-02
SLOPE - 15.00 PERCENT
DRAINAGE LENGTH = 600.0 FEET
CM/SEC
LAYER 3
TYPE 4 - FLEXIBLE MEMBRANE LINER
MATERIAL TEXTURE NUMBER 35
= 0.04 INCHES
0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
= 0.0000 VOL/VOL
= 0.199999996000E-12 CM/SEC
0.75 HOLES/ACRE
2.00 HOLES/ACRE
= 3 - GOOD
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
FML PINHOLE DENSITY
FML INSTALLATION DEFECTS
FML PLACEMENT QUALITY
LAYER 4
TYPE 3 - BARRIER SOIL LINER
MATERIAL TEXTURE NUMBER 16
24.00
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT =
INCHES
0.4270 VOL/VOL
0.4180 VOL/VOL
0.3670 VOL/VOL
0.4270 VOL/VOL
EFFECTIVE SAT. HYD. COND. = 0.100000001000E-06 CM/SEC
LAYER 5
TYPE 1 - VERTICAL PERCOLATION LAYER
MATERIAL TEXTURE NUMBER 18
THICKNESS « 300.00 INCHES
POROSITY = 0.6710 VOL/VOL
FIELD CAPACITY = 0.2920 VOL/VOL
WILTING POINT = 0.0770 VOL/VOL
-------
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
0.2920 VOL/VOL
0.100000005000E-02 CM/SEC
LAYER 6
TYPE 2 - LATERAL DRAINAGE LAYER
MATERIAL TEXTURE NUMBER 1
12.00 INCHES
0.4170 VOL/VOL
« 0.0450 VOL/VOL
0.0180 VOL/VOL
0.0451 VOL/VOL
* 0.999999978000E-02
« 1.50 PERCENT
« 600.0 FEET
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
SLOPE
DRAINAGE LENGTH
CM/SEC
LAYER 7
TYPE 4 - FLEXIBLE MEMBRANE LINER
MATERIAL TEXTURE NUMBER 35
0.06 INCHES
= 0.0000 VOL/VOL
» 0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
» 0.199999996000E-12 CM/SEC
• 0.75 HOLES/ACRE
2.00 HOLES/ACRE
• 3 - GOOD
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
FML PINHOLE DENSITY
FML INSTALLATION DEFECTS
FML PLACEMENT QUALITY
LAYER 8
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
TYPE 3 - BARRIER SOIL LINER
MATERIAL TEXTURE NUMBER 16
12.00
INCHES
0.4270 VOL/VOL
0.4180 VOL/VOL
0.3670 VOL/VOL
0.4270 VOL/VOL
0.100000001000E-06 CM/SEC
LAYER 9
TYPE 2 - LATERAL DRAINAGE LAYER
-------
HATERIAL TEXTURE NUMBER
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
SLOPE
DRAINAGE LENGTH
- 0
12.00 INCHES
0.4170 VOL/VOL
0.0450 VOL/VOL
0.0180 VOL/VOL
0.0450 VOL/VOL
.999999978000E-02
1.50 PERCENT
600.0 FEET
CM/SEC
LAYER 10
TYPE 4 - FLEXIBLE MEMBRANE LINER
MATERIAL TEXTURE NUMBER 35
0.06 INCHES
0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
• 0
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
FML PINHOLE DENSITY
FML INSTALLATION DEFECTS
FML PLACEMENT QUALITY
199999996000E-12 CM/SEC
0.75 HOLES/ACRE
2.00 HOLES/ACRE
- GOOD
LAYER 11
TYPE 3 - BARRIER SOIL LINER
MATERIAL TEXTURE NUMBER 16
36.00
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT =
INCHES
0.4270 VOL/VOL
0.4180 VOL/VOL
0.3670 VOL/VOL
0.4270 VOL/VOL
EFFECTIVE SAT. HYD. COND. = 0.100000001000E-06 CM/SEC
GENERAL DESIGN AND EVAPORATIVE ZONE DATA
NOTE: SCS RUNOFF CURVE NUMBER WAS COMPUTED FROM DEFAULT
SOIL DATA BASE USING SOIL TEXTURE # 4 WITH A
GOOD STAND OF GRASS, A SURFACE SLOPE OF 15.%
AND A SLOPE LENGTH OF 600. FEET.
SCS RUNOFF CURVE NUMBER - 50.40
FRACTION OF AREA ALLOWING RUNOFF = 100.0 PERCENT
AREA PROJECTED ON HORIZONTAL PLANE - 18.000 ACRES
EVAPORATIVE ZONE DEPTH = 24.0 INCHES
INITIAL WATER IN EVAPORATIVE ZONE - 9.350 INCHES
-------
UPPER LIMIT OF EVAPORATIVE STORAGE
LOWER LIMIT OF EVAPORATIVE STORAGE
INITIAL SNOW WATER
INITIAL WATER IN LAYER MATERIALS
TOTAL INITIAL WATER
TOTAL SUBSURFACE INFLOW
10.488 INCHES
1.128 INCHES
0.000 INCHES
133.780 INCHES
133.780 INCHES
0.00 INCHES/YEAR
EVAPOTRANSPIRATION AND WEATHER DATA
NOTE: EVAPOTRANSPIRATION DATA WAS OBTAINED FROM
SEATTLE WASHINGTON
MAXIMUM LEAF AREA INDEX
START OF GROWING SEASON (JULIAN DATE)
END OF GROWING SEASON (JULIAN DATE)
AVERAGE ANNUAL WIND SPEED
AVERAGE 1ST QUARTER RELATIVE HUMIDITY
AVERAGE 2ND QUARTER RELATIVE HUMIDITY
AVERAGE 3RD QUARTER RELATIVE HUMIDITY
AVERAGE 4TH QUARTER RELATIVE HUMIDITY
- 3.50
126
287
= 9.10 MPH
» 75.00 %
- 69.00 %
= 70.00 %
= 79.00 %
NOTE:
JAN/JUL
8.50
0.76
PRECIPITATION DATA WAS SYNTHETICALLY GENERATED USING
COEFFICIENTS FOR OLYMPIA WASHINGTON
NORMAL MEAN MONTHLY PRECIPITATION (INCHES)
FEB/AUG MAR/SEP APR/OCT MAY/NOV
5.77
1.34
4.85
2.36
3.13
4.68
1.85
7.58
JUN/DEC
1.44
-8.70
NOTE: TEMPERATURE DATA WAS SYNTHETICALLY GENERATED USING
COEFFICIENTS FOR SEATTLE WASHINGTON
NORMAL MEAN MONTHLY TEMPERATURE (DEGREES FAHRENHEIT)
JAN/JUL FEB/AUG MAR/SEP APR/OCT MAY/NOV JUN/DEC
39.10
64.80
42.80
64.10
44.20
60.00
48.70
52.50
55.00
44.80
60.20
41.00
NOTE: SOLAR RADIATION DATA WAS SYNTHETICALLY GENERATED USING
COEFFICIENTS FOR SEATTLE WASHINGTON
STATION LATITUDE
47.25 DEGREES
-------
AVERAGE MONTHLY VALUES IN INCHES FOR YEARS
1 THROUGH 100
JAN/JUL FEB/AUG MAR/SEP APR/OCT MAY/NOV JUN/DEC
PRECIPITATION
TOTALS
STD. DEVIATIONS
RUNOFF
TOTALS
STD. DEVIATIONS
EVAPOTRANSPIRATION
TOTALS
STD. DEVIATIONS
8
0
2
0
0
0
1
0
0
0
0
0
LATERAL DRAINAGE COLLECTED
TOTALS
STD. DEVIATIONS
PERCOLATION/LEAKAGE
TOTALS
STD. DEVIATIONS
6
0
1
0
.48
.73
.48
.55
.471
.000
.093
.000
.887
.803
.130
.639
5.
1.
1.
0.
0.
0.
0.
0.
1.
0.
0.
0.
55
17
86
91
096
000
512
000
166
963
124
656
4.
2.
1.
1.
0.
0.
0.
0.
2.
1.
0.
0.
95
24
62
28
007
000
065
000
109
843
234
896
3
4
1
1
0
0
0
0
2
1
0
0
.47
.85
.29
.98
.000
.000
.000
.000
.786
.378
.561
.310
1.
7.
0.
2.
0.
0.
0.
0.
2.
0.
0.
0.
83
17
92
42
000
007
000
070
124
854
713
095
1.43
8.99
0.75 ,
2.67
0.000
0.095
0.000
0.368
2.672
0.781
0.733
0 . 10*-*
FROM LAYER 2
.6818
.3824
.3233
.1023
THROUGH LAYER
0
0
0
0
LATERAL DRAINAGE COLLECTED
TOTALS
STD. DEVIATIONS
PERCOLATION/ LEAKAGE
TOTALS
0
0
0
0
.0009
.0000
.0003
.0000
5.
0.
1.
0.
4
0.
0.
0.
0.
5886
1291
0815
0345
0008
0000
0002
0000
5.
0.
0.
0.
0.
0.
0.
0.
1586
0756
9991
0815
0006
0000
0002
0000
3
0
0
0
0
0
0
0
.3013
.2970
.9407
.3890
.0003
.0000
.0001
.0000
1.
2.
0.
1.
0.
0.
0.
0.
6522
4738
5661
3277
0002
0003
0001
0002
0.8300
5.2597
0.2387
1.3733
0.0001
0.0007
0.0000
0.0003
FROM LAYER 6
.0003
.0003
.0001
.0001
THROUGH LAYER
0
0
.0000
.0000
0.
0.
0.
0.
8
0.
0.
0003
0003
0001
0001
0000
0000
0.
0.
0.
0.
0.
0.
0004
0003
0001
0000
0000
0000
0
0
0
0
0
0
.0004
.0002
.0001
.0000
.0000
.0000
0.
0.
0.
0.
0.
0.
0004
0002
0001
0000
0000
0000
0.0004
0.0003
0.0001*
0.0000
o.oo-wt)
0.0000
-------
STD. DEVIATIONS
0.0000
0.0000
LATERAL DRAINAGE COLLECTED FROM
**r
TOTALS
STD. DEVIATIONS
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
LAYER 9
0.0000
0.0000
0.0000
0.0000
0.
0.
0.
0.
0.
0.
0000
0000
0000
0000
0000
0000
0.
0.
0.
0.
0.
0.
0000
0000
0000
0000
0000
0000
0.
0.
0.
0.
0.
0.
0000
0000
0000
0000
0000
0000
0.
0.
0.
0.
0.
0.
0000
0000
0000
0000
0000
0000
r
PERCOLATION/LEAKAGE THROUGH LAYER 11
TOTALS
STD. DEVIATIONS
AVERAGES OF
DAILY AVERAGE HEAD ACROSS
0.0000
0.0000
0.0000
0.0000
MONTHLY
LAYER
AVERAGES 23.0939
0.8900
,. STD. DEVIATIONS
DAILY AVERAGE HEAD ACROSS
AVERAGES
STD. DEVIATIONS
DAILY AVERAGE HEAD ACROSS
AVERAGES
STD. DEVIATIONS
***************************
***************************
AVERAGE ANNUAL TOTALS
6.7204
0.2380
LAYER
0.0073
0.0078
0.0000
0.0000
0.0000
0.0000
AVERAGED
4
21.6862
0.3004
6.1436
0.0804
8
0.0087
0.0070
0.0014 0.0015
0.0013 0.0011
LAYER 11
0.0000
0.0000
0.0000
0.0000
********
*******
& (STD.
0.0000
0.0000
0.0000
0.0000
**********
**********
0.
0.
0.
0.
0000
0000
0000
0000
0.
0.
0.
0.
DAILY HEADS
15.
0.
5.
0.
0.
0.
0.
0.
0.
0.
0.
0.
c***
r***
DEVIATIONS)
INCHES
6914
1817
4720
1960
0096
0063
0016
0010
0000
0000
0000
0000
******
******
8.
0.
3.
0.
0.
0.
0.
0.
0.
0.
0.
0.
t***
t***
FOR YEARS
0000
0000
0000
0000
0.
0.
0.
0.
0000
0000
0000
0000
0.
0.
0.
0.
0000
0000
0000
0000
(INCHES)
3893
6942
2647
9121
0097
0056
0016
0009
0000
0000
0000
0000
******
******
1
3.
6.
1.
4.
0.
0.
0.
0.
0.
0.
0.
0.
k***
k***
8451
6162
3175
3865
0093
0053
0015
0009
0000
0000
0000
0000
*****
*****
THROUGH
CU. FEET
1.
16.
0.
6.
0.
0.
0.
0.
0.
0.
0.
0.
i!****
t****
100
9959
3563
5740
7256
0086
0059
0014
0011
0000
0000
0000
0000
*****
*****
«
T
*
?
I
f
i,
t
f
PERCENT *
-------
PRECIPITATION
RUNOFF
EVAPOTRANSPIRATION
LATERAL DRAINAGE COLLECTED
FROM LAYER 2
PERCOLATION/LEAKAGE THROUGH
FROM LAYER 4
AVERAGE HEAD ACROSS TOP
OF LAYER 4
LATERAL DRAINAGE COLLECTED
FROM LAYER 6
PERCOLATION/LEAKAGE THROUGH
FROM LAYER 8
AVERAGE HEAD ACROSS TOP
OF LAYER 8
LATERAL DRAINAGE COLLECTED
FROM LAYER 9
PERCOLATION/LEAKAGE THROUGH
FROM LAYER 11
AVERAGE HEAD ACROSS TOP
OF LAYER 11
50.86 ( 6.475)
0.676 ( 1.5808)
18.367 ( 1.9076)
31.83005 ( 4.97177)
0.00395 ( 0.00083)
8.312 ( 1.829)
0.00392 ( 0.00062)
0.00001 ( 0.00000)
0.008 ( 0.001)
0.00001 ( 0.00000)
0.00000 ( 0.00000)
0.000 ( 0.000)
3323272.0
44185.56
1200101.62
2079775.620
257.838
0.575
0.164
100.00
1.330
36.11
'•»•/•.«-- •
62.58217
0.00776-
255.990 0.00770
0.00002
0.409 0.00001
0.00000
CHANGE IN WATER STORAGE
-0.016 ( 2.8735)
-1048.51
-0.032
-------
PEAK DAILY VALUES FOR YEARS
1 THROUGH 100
PRECIPITATION
RUNOFF
DRAINAGE COLLECTED FROM LAYER 2
PERCOLATION/ LEAKAGE THROUGH LAYER 4
AVERAGE HEAD ACROSS LAYER 4
DRAINAGE COLLECTED FROM LAYER 6
PERCOLATION/ LEAKAGE THROUGH LAYER 8
AVERAGE HEAD ACROSS LAYER 8
DRAINAGE COLLECTED FROM LAYER 9
PERCOLATION/ LEAKAGE THROUGH LAYER 11
AVERAGE HEAD ACROSS LAYER 11
SNOW WATER
MAXIMUM VEG. SOIL WATER (VOL/ VOL)
MINIMUM VEG. SOIL WATER (VOL/ VOL)
(INCHES)
4.21
2.375
0.32559
0.000046
36.000
0.00002
0.000000
0.013
0.00000
0.000000
0.000
5.93
0.
0.
(CU. FT.)
275081.406
155191.7810
21273.99410
2.98295
1.23588
0.00233
0.00145
0.00045
387674.5310
4370
0371
-------
FINAL WATER STORAGE AT END OF YEAR 100
LAYER
1
2
3
4
5
6
7
8
9
10
11
SNOW WATER
(INCHES)
7.7436
5.0039
0.0000
10.2480
87.6000
0.5435
0.0000
5.1240
0.5400
0.0000
15.3720
0.000
(VOL/VOL)
0.3226
0.4170
0.0000
0.4270
0.2920
0.0453
0.0000
0.4270
0.0450
0.0000
0.4270
-------
** . **
**
** HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE **
** HELP MODEL VERSION 3.01 (14 OCTOBER 1994) **
** DEVELOPED BY ENVIRONMENTAL LABORATORY **
** USAE WATERWAYS EXPERIMENT STATION **
• ** FOR USEPA RISK REDUCTION ENGINEERING LABORATORY **
** **
** **.
PRECIPITATION DATA FILE: c:\help3\asarl.D4
TEMPERATURE DATA FILE: c:\help3\ASAR2.D7
SOLAR RADIATION DATA FILE: c:\help3\ASAR3.D13
EVAPOTRANSPIRATION DATA: c:\help3\ASAR4.Dll
SOIL AND DESIGN DATA FILE: c:\help3\asarlO.D10
OUTPUT DATA FILE: c:\help3\asarll.OUT
TIME: 12:23 DATE: 2/23/1995
TITLE: ASAR-OCF POOR CAP AND NO LINER
NOTE: INITIAL MOISTURE CONTENT OF THE LAYERS AND SNOW WATER WERE
COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM.
LAYER 1
TYPE 1 - VERTICAL PERCOLATION LAYER
MATERIAL TEXTURE NUMBER 4
THICKNESS = 24.00 INCHES
POROSITY = 0.4370 VOL/VOL
FIELD CAPACITY = 0.1050 VOL/VOL
WILTING POINT - 0.0470 VOL/VOL
INITIAL SOIL WATER CONTENT » 0.3946 VOL/VOL
EFFECTIVE SAT. HYD. COND. - 0.170000002000E-02 CM/SEC
NOTE: SATURATED HYDRAULIC CONDUCTIVITY IS MULTIPLIED BY 1.80
FOR ROOT CHANNELS IN TOP HALF OF EVAPORATIVE ZONE.
-------
LAYER 2
TYPE 2 - LATERAL DRAINAGE LAYER
MATERIAL TEXTURE NUMBER 1
THICKNESS = 12.00 INCHES
POROSITY = 0.4170 VOL/VOL
FIELD CAPACITY = 0.0450 VOL/VOL
WILTING POINT
INITIAL SOIL WATER CONTENT =
EFFECTIVE SAT, HYD. COND. = 0,
SLOPE
DRAINAGE LENGTH
0.0180 VOL/VOL
0.4170 VOL/VOL
.999999978000E-02
15.00 PERCENT
600.0 FEET
CM/SEC
LAYER 3
TYPE 4 - FLEXIBLE MEMBRANE LINER
MATERIAL TEXTURE NUMBER 35
0.04 INCHES
0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
0.0000 VOL/VOL
= 0.199999996000E-12 CM/SEC
1.00 HOLES/ACRE
15.00 HOLES/ACRE
= 4 - POOR
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
FML PINHOLE DENSITY
FML INSTALLATION DEFECTS
FML PLACEMENT QUALITY
LAYER 4
TYPE 3 - BARRIER SOIL LINER
MATERIAL TEXTURE NUMBER 28
24.00
THICKNESS
POROSITY
FIELD CAPACITY
WILTING POINT
INITIAL SOIL WATER CONTENT =
INCHES
0.4520 VOL/VOL
0.4110 VOL/VOL
0.3110 VOL/VOL
0.4520 VOL/VOL
EFFECTIVE SAT. HYD. COND. = 0.120000004000E-05 CM/SEC
LAYER 5
TYPE 1 - VERTICAL PERCOLATION LAYER
MATERIAL TEXTURE NUMBER 18
THICKNESS = 300.00 INCHES
POROSITY = 0.6710 VOL/VOL
FIELD CAPACITY - 0.2920 VOL/VOL
WILTING POINT = 0.0770 VOL/VOL
-------
INITIAL SOIL WATER CONTENT
EFFECTIVE SAT. HYD. COND.
0.2585 VOL/VOL
0.100000005000E-02 CM/SEC
GENERAL DESIGN AND EVAPORATIVE ZONE DATA
NOTE: SCS RUNOFF CURVE NUMBER WAS COMPUTED FROM DEFAULT
SOIL DATA BASE USING SOIL TEXTURE # 4 WITH A
POOR STAND OF GRASS, A SURFACE SLOPE OF 15.%
AND A SLOPE LENGTH OF 600. FEET.
SCS RUNOFF CURVE NUMBER
FRACTION OF AREA ALLOWING RUNOFF
AREA PROJECTED ON HORIZONTAL PLANE
EVAPORATIVE ZONE DEPTH
INITIAL WATER IN EVAPORATIVE ZONE
UPPER LIMIT OF EVAPORATIVE STORAGE
LOWER LIMIT OF EVAPORATIVE STORAGE
INITIAL SNOW WATER
INITIAL WATER IN LAYER MATERIALS
TOTAL INITIAL WATER
TOTAL SUBSURFACE INFLOW
74.40
100.0
18.000
24.0
9.472
10.488
1.128
0.000
102.873
102.873
0.00
PERCENT
ACRES
INCHES
INCHES
INCHES
INCHES
INCHES
INCHES
INCHES
INCHES/ YEAR
EVAPOTRANSPIRATION AND WEATHER DATA
NOTE: EVAPOTRANSPIRATION DATA WAS OBTAINED FROM
SEATTLE WASHINGTON
MAXIMUM LEAF AREA INDEX = 1.00
START OF GROWING SEASON (JULIAN DATE) - 126
END OF GROWING SEASON (JULIAN DATE) = 287
AVERAGE ANNUAL WIND SPEED = 9.10 MPH
AVERAGE 1ST QUARTER RELATIVE HUMIDITY = 75.00 %
AVERAGE 2ND QUARTER RELATIVE HUMIDITY = 69.00 %
AVERAGE 3RD QUARTER RELATIVE HUMIDITY - 70.00 %
AVERAGE 4TH QUARTER RELATIVE HUMIDITY = 79.00 %
NOTE:
JAN/JUL
8.50
0.76
PRECIPITATION DATA WAS SYNTHETICALLY GENERATED USING
COEFFICIENTS FOR OLYMPIA WASHINGTON
NORMAL MEAN MONTHLY PRECIPITATION (INCHES)
FEB/AUG MAR/SEP APR/OCT MAY/NOV
5.77
1.34
4.85
2.36
3.13
4.68
1.85
7.58
JUN/DEC
1.44
8.70
NOTE: TEMPERATURE DATA WAS SYNTHETICALLY GENERATED USING
-------
COEFFICIENTS FOR SEATTLE WASHINGTON
NORMAL MEAN MONTHLY TEMPERATURE (DEGREES FAHRENHEIT)
JAN/JUL FEB/AUG MAR/SEP APR/OCT MAY/NOV JUN/DEC
39.10 42.80 44.20 48.70 55.00 60.20
64.80 64.10 60.00 52.50 44.80 41.00
NOTE: SOLAR RADIATION DATA WAS SYNTHETICALLY GENERATED USING
COEFFICIENTS FOR SEATTLE WASHINGTON
* STATION LATITUDE =
= 47.25 DEGREES
****************************************************
AVERAGE MONTHLY VALUES IN INCHES FOR YEARS
JAN/JUL
PRECIPITATION
TOTALS 8.48
0.73
STD. DEVIATIONS 2.48
0.55
RUNOFF
TOTALS 0.759
0.000
STD . DEVIATIONS 1.248
0.000
EVAPOTRANSPIRATION
TOTALS 0.905
1.830
STD. DEVIATIONS 0.135
0.594
LATERAL DRAINAGE COLLECTED FROM
TOTALS 6.0866
0.4098
i STD. DEVIATIONS 0.8787
0.1305
FEB/AUG
5.55
1.17
1.86
0.91
0.211
0.001
0.611
0.007
1.192
0.946
0.128
0.625
LAYER 2
5.2809
0.3022
0.8563
0.0716
MAR/ SEP
4.95
2.24
1.62
1.28
0.020
0.000
0.074
0.001
2.135
1.840
0.239
0.784
5.0379
0.1549
0.9630
0.0932
******************** ********
1 THROUGH 100
APR/OCT
3.47
4.85
1.29
1.98
0.000
0.016
0.002
0.042
2.799
1.417
0.562
0.311
3.2242
0.3263
0.9714
0.3827
MAY/NOV
1.83
7.17
0.92
2.42
0.000
0.102
0.000
0.245
1.971
0.896
0.723
0.093
1.5906
2.3414
0.5746
1.2727
JUN/DEC
1.43
8.99
0.75
2.67
0.000
0.268
0.000
0.489
1.667
0.804
•3
0.655
0.102
*
0.6625
4.9313
1.1089
-------
PERCOLATION/LEAKAGE THROUGH LAYER 4
TOTALS
STD. DEVIATIONS
0.1734
0.0091
0.0541
0.0026
0.1474
0.0069
0.0446
0.0015
0.1187
0.0038
0.0434
0.0019
0.0632
0.0070
0.0246
0.0074
0.0312
0.0476
0.0103
0.0299
0.0140
0.1189
0.0043
0.0479
PERCOLATION /LEAKAGE THROUGH LAYER 5
TOTALS
STD. DEVIATIONS
AVERAGES
0.0976
0.0589
0.0579
0.0626
OF MONTHLY
DAILY AVERAGE HEAD ACROSS LAYER
AVERAGES
STD. DEVIATIONS
22.9199
0.9538
7.4144
0.3036
0.0942
0.0809
0.0490
0.0486
AVERAGED
4
21.7227
0.7033
6.8048
0.1667
0.0939
0.0830
0.0554
0.0411
0.0696
0.0849
0.0556
0.0407
0.0424
0.0807
0.0645
0.0376
0.0366
0.0828
0.0646
0.0373
DAILY HEADS (INCHES)
15.5777
0.3726
5.9889
0.2241
8.2423
0.7612
3.4758
0.8942
3.7024
6.1819
1.3393
4.1311
1.5931
15.6073
0.5390
6.6014
AVERAGE ANNUAL TOTALS & (STD. DEVIATIONS) FOR YEARS 1 THROUGH 100
PRECIPITATION
RUNOFF
EVAPOTRANSPIRATION
LATERAL DRAINAGE COLLECTED
INCHE
50.86 (
1.377 (
18.403 (
30.34872 (
S
6.475)
1.8037)
1.8619)
4.43701)
CU. FEET
3323272.0
89991.96
1202469.50
1982985.250
PERCENT
100.00
2.708
36.183
59.66967
PERCOLATION/LEAKAGE THROUGH
FROM LAYER 4
- AVERAGE HEAD ACROSS TOP
OF -LAYER 4
PERCOLATION/LEAKAGE THROUGH
FROM LAYER 5
tHANGE IN WATER STORAGE
0.74124 ( 0.16771)
8.195 ( 1.963)
0.90567 ( 0.58497)
-0.174 ( 2.9367)
48432.398
59176.180
-11351.36
1.45737
1.78066
-0.342
-------
PEAK DAILY VALUES FOR YEARS
1 THROUGH 100
PRECIPITATION
RUNOFF
DRAINAGE COLLECTED FROM LAYER 2
PERCOLATION/ LEAKAGE THROUGH LAYER 4
AVERAGE HEAD ACROSS LAYER 4
PERCOLATION/LEAKAGE THROUGH LAYER 5
SNOW WATER
(INCHES)
4.21
2.396
0.24520
0.008608
35.941
0.021394
5.93
(CU. FT.)
275081.406
156543.9220
16021.60160
562.45880
1397.89368
387674.5310
MAXIMUM VEG. SOIL WATER (VOL/ VOL)
MINIMUM VEG. SOIL WATER (VOL/VOL)
0.4370
0.0406
-------
FINAL WATER STORAGE AT END OF YEAR 100
LAYER
1
2
3
4 -
5
SNOW WATER
(INCHES)
8.5417
5.0039
0.0000
10.8480
61.1068
0.000
(VOL/VOL)
0.3559
0.4170
0.0000
0.4520
0.2037
-------
APPENDIX E
STATE DEPARTMENT OF ECOLOGY'S CONCURRENCE LETTER
-------
STATE OF WASHINGTON
DEPARTMENT OF ECOLOGY
P.O. Box 47600 • Olympia, Washington 98504-7600 • (206) 407-6000 • TDD Only (Hearing Impaired) (206) 407-6006
March 22, 1995
Mr. Randy Smith
US EPA Region X
1200 Sixth Avenue
Seattle, WA 98101
Dear Mr. Smith:
Re: Record of Decision for the Asarco Tacoma Smelter Facility
The State of Washington concurs with the selected remedy and phased approach described in
this Record of Decision for the Asarco Tacoma Smelter facility. The combination of
measures to excavate and consolidate the more highly contaminated soils and debris in a
containment facility with design equivalent to federal hazardous waste disposal standards, to
cap the entire site, and to provide certain site restrictions is appropriate and protective against
exposure to such soils.
The current ROD provides for measures to divert surface waters from contact with
contaminants, however, the ROD provides for additional remedial measures to be taken on
surface water, should such further measure be necessary. The current ROD is an interim
action for ground water. Final ground water remediation will be addressed in a separate,
second-phase ROD that will be prepared after the impacts of the soils actions and water
diversion measures have been evaluated. Tiiis approach and the selected remedy are deemed
to be in compliance with the environmental laws and regulations of the state.
If you have any questions, please contact Bruce Cochran at (360)407-7227.
Sincerely,
Mary E. Burg, Program Manager
Toxics Cleanup Program
MEB:gj
cc: Bruce Cochran, Ecology
-------
APPENDIX F
ADMINISTRATIVE RECORD INDEX
Due to its large size,
the administrative record index is not included
but may be obtained from the Region.
------- |