United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R10-93/062
June 1993
v°/EPA Superfund
Record of Decision:
Commencement Bay -
Nearshore/Tideflats, WA
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R010-93/062
3. Recipient's Accession No.
4. Till* and Subtitle
SUPERFUND RECORD OF DECISION
Commencement Bay - Nearshore/Tideflats, WA
Fourth Remedial Action
5. Report Date
06/16/93
7. Author(s)
8. Performing Organization Rapt. No.
9. Performing Organization Nam* and Addraaa
10 Project Taak/Work Unit No.
11. Contrtct(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/800
14.
15. Supplementary Not**
PB94-964626
16. Abstract (Limit: 200 words)
The 67-acre Commencement Bay-Nearshore/Tideflats site, a former lead and copper
smelting facility, is part of the larger 950-acre property located in Ruston and
Tacoma, Washington. Land use in the area is residential, including schools,
playgrounds, and parks. The site also contains the Asarco smelter, inactive since 1985,
approximately 4,000 residents, and part of a coastal zone. In 1890 lead smelting
operations began, but in 1912, Asarco converted the plant to a copper smelter. The
smelting process specialized in processing ores with high arsenic concentrations and
also recovered arsenic-trioxide and metallic arsenic as by-products. As part of the
processing of copper from ores and concentrates, slag, a hard, glassy material
containing elevated concentrations of arsenic, lead, and other metals, was produced.
Smelter slag was used around the community for driveways, walkways, curbs, parking
areas, and as backfill in utility trenches. In 1985, copper smelting operations
ceased, and the arsenic production plant closed in 1986. As a direct result of 95
years of airborne emissions from smelting operations, historical studies throughout the
1970s and 1980s identified elevated contaminant concentrations in multiple
environmental media, including soil, house dusts, indoor and outdoor air, and garden
vegetables. Once copper smelting and arsenic processing ceased, ambient air
(See Attached Page)
17. Document Analysis a. Descriptor*
Record of Decision - Commencement Bay - Nearshore/Tideflats, WA
Fourth Remedial Action
Contaminated Media: soil, debris (slag)
Key Contaminants: metals (arsenic, lead)
b. Identlfiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
82
22. Price
(S«8 ANSI-Z39.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R010-93/062
Commencement Bay - Nearshore/Tideflats, WA
Fourth Remedial Action
Abstract (Continued)
concentrations of these metals were reduced by more than 90 percent. In 1985 and 1988,
State investigations indicated that ingestion of contaminated soil was the primary route
of exposure to arsenic. In 1989, EPA required Asarco to remove contaminated soil to a
depth of three inches at the 11 nonresidential high-use properties, and to replace the
excavated soil with 9-12 inches of imported soil. EPA has divided the Commencement Bay -
Nearshore/Tideflats site into seven OUs for remediation; four of which are associated with
the Asarco Smelter. Three previous 1998, 1989, and 1990 RODs addressed source and ground
water contamination at the site as OUs 3, 1 and 5, and 7, respectively. This ROD
addresses the arsenic- and lead-contaminated soil and slag in the area surrounding the
smelter, known as the Ruston/North Tacoma Study Area, as OU4. Future RODs will address
the contaminated soil, sediment, ground water, and surface water at the site, as OUs 2, 6,
and 7. The primary contaminants of concern affecting the soil, and slag/debris are
metals, including arsenic and lead.
The selected remedial action for this site includes sampling individual properties to
determine if soil exceeds the established EPA action levels of 230 mg/kg for arsenic and
500 mg/kg for lead, followed by excavation of any contaminated soil and slag to a depth of
18 inches; replacing the excavated soil and slag with clean soil and gravel and
re-landscaping; capping contaminated dirt alleys and parking areas with asphalt to provide
an impermeable barrier to contaminants, or removing the soil and replacing it with gravel;
disposing of the contaminated soil offsite; implementing a maintenance and monitoring
program for the capped areas; placing a marker to clearly identify the base of the cap;
fencing and planting low-lying shrubs in steeps contaminated areas where excavation is not
possible; establishing a temporary staging area or transfer facility for excavated soil,
if necessary; implementing safety measures, including air monitoring; developing a soil
testing, collection, and disposal program to remove soil from residences; and developing
and implementing institutional controls. The estimated present worth cost for this
remedial action ranges from $60,000,000 to $80,000,000, which includes an O&M cost of
$2,000,000 for 7 years.
PERFORMANCE STANDARDS OR GOALS:
Soil cleanup goals are based on reduction of the additional potential skin cancer risk of
arsenic to no more than 5 in 10,000; a national goal of reducing lead levels in children's
blood to no greater than 10 ug/dl; and EPA guidance for soil lead cleanup levels,
including arsenic 230 mg/kg and lead 500 mg/kg.
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RECORD OF DECISION
COMMENCEMENT BAY NEARSHORE/
TIDEFLATS SUPERFUND SITE
OPERABLE UNIT 04
RUSTON/NORTH TACOMA STUDY AREA
RUSTON AND TACOMA, WASHINGTON
June 1993
EPA Region 10
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DECLARATION FOR THE RECORD OF DECISION
Site Name and Location
Commencement Bay Nearshore/Tideflats Superfund Site
Operable Unit 04 -- Ruston/North Tacoma Study Area
Ruston and Tacoma, Washington
Statement of Basis and Purpose
This decision document presents the selected remedial action for the Ruston/North
Tacoma Study Area, in Ruston and Tacoma, Washington, which was chosen in
accordance with CERCLA, as amended by 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.
Assessment of the Site
Actual or threatened releases of hazardous substances from this site, if not addressed
by implementing the response action selected in this Record of Decision (ROD), may
present an imminent or substantial endangerment to public health, welfare, or the
environment.
Description of the Selected Remedy
The EPA has divided the Commencement Bay/Nearshore Tideflats Superfund site into
seven operable units (OU's) in order to facilitate the investigation, analysis, and
cleanup of this very large site. Four of these OU's are associated with the Asarco
smelter:
o OU 02 Asarco Tacoma Smelter
o OU 04 Asarco Off-Property (Ruston/North Tacoma Study Area)
o OU 06 Asarco Sediments
o OU 07 Asarco Demolition
The remedy described in this ROD addresses OU 04 and involves the cleanup of
arsenic and lead contaminated soils and slag in the Study Area, the residential
community surrounding the smelter. This remedy will address the principal threat
posed by conditions at the site, which is the ingestion of contaminated soil and dust,
and includes:
o Designation of "action levels" or concentrations of arsenic or lead in soil.
Engineering measures will address properties or areas that exceed action levels.
o Sampling of individual properties to determine if soil exceeds the action levels.
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o Excavation and off-site disposal of contaminated soil and slag from properties that
exceed action levels. Contaminated soil below 18 inches will not be excavated
but will be capped.
o Excavation of slag from all other properties.
o Replacement of excavated soil and slag with clean soil and gravel.
o Asphalt capping or soil removal and replacement with gravel of contaminated dirt
alleys and parking areas.
o Fencing and planting low lying shrubs in steep areas.
o Soil collection program for soil above action levels that is not excavated during the
cleanup (e.g., soil below 18 inches that is uncovered in the future).
o The development and implementation of community protection measures (CPMs).
CPMs are administrative requirements that will address soil that is not excavated
but that contains concentrations of arsenic or lead that exceed either action levels
or levels commonly found in urban areas.
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 not found to be
practicable, this remedy does not satisfy the statutory preference for treatment as a
principal element.
Because the remedy may 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.
Gerald A. Emison Date
Acting Regional Administrator
U.S. EPA Region 10
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RECORD OF DECISION
COMMENCEMENT BAY NEARSHORE/
TIDEFLATS SUPERFUND SITE
OPERABLE UNIT 04
RUSTON/NORTH TACOMA STUDY AREA
RUSTON AND TACOMA, WASHINGTON
June 1993
EPA Region 10
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TABLE OF CONTENTS
1.0 SITE DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2
2.1 Cleanup Activities in Areas Surrounding the Smelter Site 2
2.2 Cleanup Activities at the Smelter Site 4
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 4
3.1 Outreach 4
3.2 Education 6
4.0 SCOPE AND ROLE OF OPERABLE UNITS 6
4.1 Scope of Current Work 6
4.2 Other Related Activities 7
5.0 SITE CHARACTERISTICS 7
5.1 Sources of Contamination 7
5.2 Nature and Extent of Contamination 8
5.3 Contaminant Migration 9
5.4 Affected Population 10
6.0 SITE RISKS 10
6.1 Identification of Contaminants of Concern 10
6.2 Exposure Assessment 10
6.3 Toxicity Assessment ....'. 11
6.4 Epidemiological Studies 12
. 6.5 Risk Characterization 12
6.6 Uncertainty in the Risk Assessment 13
6.7 Potential Health Risks Exceed Acceptable Levels 13
6.8 Remedial Action Objectives and Goals 13
6.9 Environmental Risks 14
7.0 DESCRIPTION OF ALTERNATIVES 15
7.1 Alternative 1 - No Action 16
7.2 Common Components of the Alternatives 16
7.3 Alternative 2 - Limited Action 18
7.4 Alternative 3 - Containment of Contaminated Soil 19
7.5 Alternative 4a and 4b - Excavate 1 Foot of Soil/Backfill/Temporary Storage at
Asarco Smelter Facility/Permanent Disposal 19
7.6 Alternative 5 - Excavate 1 Foot of Soil/Backfill/Disposal 21
7.7 Alternative 6 - Excavate to Depth at Which Background Contaminant Levels
Are Achieved/Backfill/Disposal 21
7.8 General Principles and Guidelines 22
7.9 The Preferred Alternative 22
8.0 COMPARATIVE ANALYSIS OF ALTERNATIVES 24
8.1 Overall Protection of Human Health and the Environment '. 24
8.2 Compliance with Federal and State Environmental Standards 24
8.3 Long-Term Effectiveness and Permanence 25
8.4 Reduction of Toxicity, Mobility, or Volume through Treatment 26
8.5 Short-Term Effectiveness 26
8.6 Implementability -. 27
8.7 Cost r 27
iii
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TABLE OF CONTENTS (Continued)
8.8 State Acceptance 27
8.9 Community Acceptance , 28
9.0 THE SELECTED REMEDY 29
9.1 Sampling 29
9.2 Small Quantity Soil Disposal Program 29
9.3 Excavation of Contaminated Soil, Sod, and Slag 30
9.4 Properties or Areas Where Soil Above Action Levels Remains 30
9.5 Dirt Alleys and Parking Areas 31
9.6 Fencing 31
9.7 Cleanup Timeframe, Schedule and Prioritization 31
9.8 Information for Deed Notice : 31
9.9 Safety Measures 31
9.10 Community Protection Measures 31
9.11 Funding 33
9.12 Expedited Response Action Properties 33
9.13 Disposal 34
9.14 Homeowner Access and Approval 34
9.15 Landscaping 35
9.16 Community Relations During Cleanup 35
9.17 Incidental Damage During Remediation 35
9.18 Cost of the Selected Remedy 35
10.0 STATUTORY DETERMINATIONS .- 36
10.1 Protection of Human Health and the Environment 36
10.2 Compliance with Applicable or Relevant and Appropriate Requirements 36
10.3 Cost-Effectiveness 36
10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to
the Maximum Extent Practicable 38
10.5 Preference for Treatment as a Principal Element 38
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES 38
IV
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TABLE OF CONTENTS (Continued)
LIST OF FIGURES
Figure 1. Ruston/North Tacoma Study Area
Figure 2. Expedited Response Action Sites
Figure 3. Total Arsenic Distribution FIR & Rl Data, Surface Soil
Figure 4. Total Lead Concentration Rl & FIR Data, Surface Soil
Figure 5. Study Area and Estimated Portions Exceeding Action Levels
Figure 6. Proposed Fenced Area
LIST OF TABLES
Table 1. Ruston/North Tacoma Study Area Information Repositories
Table 2. List and Description of Fact Sheets and Brochures Regarding the Ruston/North
Tacoma Study Area
Table 3. Combined Remedial Investigation and Field Investigation Report Data for Surface and
Subsurface Soil Samples from the Study Area
Table 4. Summary of Arsenic Exposure Factors
Table 5. Exposure Factors for the Garden Vegetable Exposure Model for Arsenic
Table 6. Summary of Average Daily Dose at Various Soil Arsenic Concentrations
Table 7. Average Daily Dose for Arsenic in the Slag/Dust and Air RME Models
Table 8. Exposure Parameter Average Values for the UBK Model for O'to 6 Year Old Children
Table 9. Estimated Lead Uptake by Children in Study Area
Table 10. Estimated Upper Bound Lifetime Cancer Risks from Exposure to Arsenic
Table 11. Estimated Lifetime Noncancer Risks from Exposure to Arsenic
Table 12. Remedial Action Objectives and Remediation Goals
Table 13. Summary of Remedial Action Alternatives
Table 14. Unit Quantity Estimates for Remedial Action Levels of 230 ppm and Greater of Arsenic,
and 500 ppm and Greater of Lead
Table 15. Evaluation Criteria
Table 16. Ruston/North Tacoma - Summary of Applicable or Relevant and Appropriate
Requirements
Table 17. Estimated Costs of Remedial Action Alternatives
APPENDIX A . RUSTON/NORTH TACOMA RESIDENTIAL STUDY AREA RESPONSIVENESS
SUMMARY
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RECORD OF DECISION SUMMARY
RUSTON/NORTH TACOMA STUDY AREA
RUSTON AND TACOMA, WASHINGTON
1.0 SITE DESCRIPTION
The Ruston/North Tacoma Study Area (Study Area) is an operable unit of the 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 Study Area, approximately 950 acres,
comprises an arc of approximately one mile radius surrounding the Asarco Tacoma smelter (Asarco
smelter) and consists of the Town of Ruston and a northern portion of the City of Tacoma,
Washington (Figure 1). The EPA and the Washington State Department of Ecology (Ecology)
identified the Study Area as the primary focus for conducting a Remedial Investigation/Feasibility
Study (RI/FS) (see Section 2.0 for a discussion of how the Study Area was defined). This Record of
Decision (ROD) addresses contaminated soils and slag within the residential Study Area surrounding
the Asarco smelter.
The smelter began operations in 1890 as a lead smelter. Asarco purchased the smelter in
1905 and converted it to a copper smelter in 1912. The smelter specialized in processing ores with
high arsenic concentrations and recovered arsenic trioxide and metallic arsenic as by-products. In
recovering copper from ores and concentrates, the smelting process also produced slag, a hard,
glassy material containing elevated concentrations of arsenic, lead, and other metals. Copper
smelting operations ceased in 1985, and the arsenic production plant was closed in 1986. The
Asarco smelter facility, including demolition of structures on the smelter property, and sediments
adjacent to the smelter property are being addressed as separate operable units of the CB N/T
Superfund site (see Section 4.0).
The Study Area land use is primarily residential and includes schools, playgrounds, and parks.
The Study Area includes a population of approximately 4,290, and about 1,820 housing units.
Commercial development consisting of retail shops and small businesses is limited in extent and
mainly confined to an area along Pearl Street. The Asarco smelter, which ceased operations in 1985,
is located to the northeast of the Study Area and was the principal industrial facility in the area. The
southern portion of Point Defiance Park and Zoo, which extends along a wooded peninsula to the
northwest of the smelter, is located within the Study Area and includes access to the Vashon Island
Ferry. Properties to the southeast of the Study Area, which were previously industrial in nature, are
actively being redeveloped with restaurants, a fishing pier, park areas, and other public uses.
The Study Area is characterized by a rolling topography. Elevations, according to United
States Geological Survey documents, range from 10 feet (3 meters) above Mean Sea Level (MSL) to
250 feet (75 meters) MSL, with elevations decreasing at a fairly uniform rate towards the northeast
(Commencement Bay). High bluffs form the shoreline boundary of the Study Area separating it from
Commencement Bay and the Asarco smelter facility. Steep ravines occur in the vicinity of rail tracks
that cross the site in an east-west direction. There are areas of dense vegetation, such as steep
slopes of ravines (particularly southwest and west of the Asarco property) and along the slope toward
Commencement Bay above Ruston Way. In general, however, construction of residences has resulted
in clearing most of the area with the exception of scattered trees and landscaping.
Few surface water features exist within the Study Area. Some springs emerge from shallow
ground water zones along the face of the shoreline bluffs. A field investigation of ground water
conditions was not included as part of the Rl. Based on the impermeable characteristics of the till and
silts, the presumed depth to ground water, and the characteristics of the contaminants, it is not
considered likely that contamination from Asarco smelter airborne emissions has migrated to the
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ground water or substantially affected ground water quality. Ground water in the Study Area is not
currently used as a source for drinking water.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
. Operation of the Asarco smelter for over 95 years resulted in contamination of various
environmental media in the surrounding area. That contamination was the result of airborne
emissions from smelting operations. Early soil sampling studies as well as deposition modeling were
useful in suggesting the overall pattern of soil contamination with distance and direction from the
smelter. The Exposure Pathway Study (discussed further below) conducted by the University of
Washington included additional sampling locations, and provided information on soil contamination at
the time of the smelter closure in 1985-1986.
In 1988 a Field Investigation Report (FIR) was developed for the Washington State Department
of Ecology. Based on a review of all available soil sampling results, sampling for the FIR wz •
designed to characterize soil contamination patterns in an area out to about 100 parts per r on
(ppm) arsenic, which was interpreted to be at a distance of about 3/4 to 1 mile from the sme.-.er.
The EPA RI/FS work plans were developed in 1989. The sampling focused on the same
Study Area as the FIR, and was designed to address data gaps, areas of uncertainty, and develop
additional spatial data.
Subsequent to all of these soil sampling studies, the Cleanup Standards under the Model
Toxics Control Act (MTCA) were adopted by Ecology (February 1991). The cleanup standard for soil
arsenic in residential areas as defined in the regulation would result in a larger area for characterizing
the extent of soil contamination by arsenic (to an area defined by 20 ppm rather than by 100 ppm).
This ROD, however, addresses contaminated soils and slag within the more limited Study Area
surrounding the former smelter site as defined for the Rl study (see also Section 4.1).
Asarco is liable under the Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA or the Superfund law) for the cost of cleanup of hazardous substances that
were released from the smelter. EPA first notified Asarco of its potential liability for the contamination
of the area surrounding the smelter in July 1984. EPA had previously notified Asarco of its potential
liability for the contamination of Commencement Bay in March 1982.
2.1 Cleanup Activities in Areas Surrounding the Smelter Site
The residential area adjacent to the smelter has been the subject of many investigations over
the past 20 years (see summary of reports on pages 1-8 through 1-13 of the Remedial Investigation
(Rl) Report for Ruston/North Tacoma, Washington, Bechtel, January 1992). Several recent studies,
mentioned above, are described in the following text. These studies are significant in that they formed
the basis for a 1989 EPA decision to conduct an Expedited Response Action (ERA) at several publicly
accessible properties in the Study Area.
Exposure Pathways Study
Initiated in 1985 and released in 1987, the Exposure Pathways Study (Ruston/Vashon Arsenic
Exposure Pathways Study, University of Washington, 1987) investigated the pathways contributing
arsenic to the bodies of residents in Tacoma and Vashon/Maury Islands. One of the objectives of this
study was to determine what environmental media required remediation to effectively reduce the body
burden of arsenic in the affected population. The study involved the repeated sampling of urine and a
number of environmental media for arsenic analyses. It was performed just at the time when smelter
operations ceased.
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In the Exposure Pathways Study, an individual's age was shown to be significant for
determining urinary arsenic levels, with young children most affected. Among other findings, the
arsenic concentrations on children's hands were significantly associated with urinary arsenic
concentrations, and with time spent in contact with soil and house dust. Ingestion of contaminated
soil was identified as the primary route of exposure to arsenic.
Field Investigation Report
In 1988, a detailed investigation (Field Investigation Report [FIR], Ruston/Vashon Island Area,
Black & Veatch, 1988) of post-shutdown soil contamination in the Study Area was performed by
Ecology. Approximately 288 soil samples were collected from residential and non-residential high-use
areas (parks, playgrounds, and vacant lots) within approximately 1 mile of the smelter. The FIR
included an evaluation to determine if soil contamination was related to smelter emissions.
Endanoerment Assessment and Engineering Evaluation/Cost Analysis
In conjunction with the FIR, an Endangerment Assessment (EA) (Endangerment Assessment
Ruston/Vashon Island Area, Black & Veatch, 1988) and Engineering Evaluation/Cost Analysis (EE/CA)
(Engineering Evaluation/Cost Analysis of Removal Action Alternatives: Ruston/Vashon Island Area,
Black & Veatch, 1988) were also performed by Ecology. The EA evaluated the potential health effects
from exposure to smelter-related contamination in soil, house dust, and air. The EE/CA was
developed to evaluate removal action alternatives.
Urinary Arsenic Survey
As a follow-up to the Exposure Pathways Study, an additional urinary arsenic survey (Urinary
Arsenic Survey, North Tacoma, Washington, Tacoma-Pierce County Health Department, 1988) was
performed by the Tacoma-Pierce County Health Department (TPCHD) of children ages 2 - 8 years
living within approximately 1/2 mile of the smelter. The results indicated that urinary arsenic levels had
generally declined since smelter closure. Some individuals, however, still had elevated levels.
Expedited Response Action
Of the 20 nonresidential high-use areas identified and sampled as part of the FIR, 11 were
determined to have arsenic concentrations resulting in estimated risks outside of EPA's range of
acceptable risks for carcinogens. In March 1989; EPA and Asarco signed an Administrative Order on
Consent for the performance of an ERA. Under the ERA, Asarco agreed to remove three inches of
arsenic-contaminated soil at the 11 nonresidentjal high-use properties, and replace the excavated soil
with 9 to 12 inches of imported soil. The 11 sites (see Figure 2) totalled about 15 acres and included
playgrounds, parks, and vacant lots - locations where children were likely to spend time playing.
While additional information was required to fully characterize the nature and extent of contamination
in the residential community, these nonresidential sites were selected for early remedial action
because of elevated concentrations of arsenic in soil, and accessibility by the public, especially
children. A portion of one of the sites has not been cleaned-up due to difficulties in securing access
from the property owner.
Remedial investigation/Feasibility Study
In 1989, EPA contacted Asarco about conducting the further investigation and analysis of
cleanup alternatives. Asarco was not willing to conduct the investigation and analysis as required by
EPA, so EPA funded and performed this work. EPA released its Baseline Risk Assessment, Rl, and
Feasibility Study in January 1992.
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2.2 Cleanup Activities at the Smelter Site
In addition to the investigation and cleanup of the residential community, EPA and Asarco are
also investigating and analyzing cleanup options for the smelter property, and for contaminated
marine sediments adjacent to the smelter site. See Section 4.0 for a brief description of these
activities.
3.0 HIGHUGHTS OF COMMUNITY PARTICIPATION
Throughout EPA's RI/FS activities leading up to this ROD, extensive efforts have been made to
inform and involve the public, particularly residents in the community. EPA conducted the activities
summarized in this section because the agency believes that community involvement is a key element
in developing and implementing a successful cleanup plan.
In addition to the many 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 14,1992. The Proposed Plan public comment period ran from August 17, 1992
through October 17, 1992. During the comment period EPA held two public meetings. The Proposed
Plan was mailed to approximately 800 individuals on EPA's mailing list. A summary fact sheet of the
Proposed Plan was also sent to all residents of the Study Area by a postal carrier route bulk mailing.
EPA also published newspaper advertisements in Tacoma's Morning News Tribune to announce the
availability of the Proposed Plan, the comment period, and the public meetings.
To prepare for the release of the Proposed Plan, EPA developed a communications strategy in
1990 for its activities related to the Ruston/North Tacoma Study Area The communications strategy
included three main components: Community Relations; Periodic Briefings; and the formation of a
Coordinating Forum. This strategy supplemented the existing Community Relations Plan (September
1989), which addresses all of the CB N/T Operable Units. The following summarizes the numerous
community relations activities that EPA has conducted to date. Many activities are on-going activities.
The activities are listed below as either outreach or education.
3.1 Outreach
General Public
Community Liaison: In 1989, EPA hired a part time community liaison. The EPA liaison staffs
an office in Ruston three days a week to answer questions and research information for Citizens. He
also participates in many of EPA's public involvement activities, including speaking at local community
organization's meetings. EPA staff in Seattle also respond to numerous public telephone inquiries.
Communitv Workgroup: Also in 1989, EPA began a Community Workgroup. Community
members were invited to attend by way or a fact sheet that was mailed to residents throughout the
Study Area. EPA has since been meeting regularly with the workgroup. EPA often presents ideas to
the group for outreach efforts as well as draft language for public information documents (fact sheets,
brochures) for feedback and comments. The workgroup provides valuable input to EPA.
Open houses: In January 1991 EPA held three open houses to provide citizens in Ruston and
North Tacoma an opportunity to meet representatives of EPA, and to hear the citizens interests and
concerns about EPA's efforts to conduct an RI/FS. The open houses were advertised through a notice
which was mailed to the Study Area and through newspaper advertisements.
Communitv interviews: During February, March, and April 1991 EPA interviewed 46 concerned
people in the Ruston and North Tacoma communities to learn about community concerns, desired
involvement in the project, and suggestions about how to best involve the entire community.
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Public Comment Periods: From February 17 through April 17, 1992 EPA held a 60 day public
comment period on its Rl, Risk Assessment, Feasibility Study and other documents in the
Administrative Record. This was the first of two public comment periods to provide residents and
officials an opportunity to comment on the cleanup alternatives considered by EPA.
The second comment period, which ran from August 17 through October 17, 1992 focused on
EPA's Proposed Plan including the preferred clean-up alternative. Comments received during these
two public comment periods are summarized along with EPA's responses in the attached
Responsiveness Summary (Appendix A).
Communitv Workshops/Public Meetings: During the first public comment period, community
workshops were held on March 11 and March 31, 1992. Both workshops were well attended
(approximately 100 people attended the first workshop and 200 attended the second). The purpose
of the workshops was to provide an opportunity for residents to ask questions, provide comments,
and learn more about the cleanup alternatives for the site. A transcript was taken of the March 31
meeting, and EPA has prepared a summary of the March 11 workshop. The transcript and summary
are available in EPA's Administrative Record for the Study Area (see Table 1).
During the second public comment period EPA held two public meetings. At the meetings,
participants learned more about EPA's Proposed Plan and preferred cleanup alternative and had the
opportunity to provide public comments. Transcripts were taken of these two meetings (held
September 2 and October 1, 1992). The transcripts are available in EPA's Administrative Record for
the Study Area (see Table 1).
Small group meetings: Upon request, EPA staff have attended group meetings such as
bankers and appraisers associations, Kiwanis, rotary and garden clubs, senior citizens centers,
schools, and citizens groups. EPA interacts with these groups in order to educate interested groups
about EPA's activities, and to learn about different groups concerns and needs for information about
the site. EPA staff continue to meet with small groups as requested.
Elected Officials/Local Government
Periodic Briefings: Briefings have been held for the Town of Ruston, City of Tacoma, Tacoma
Environmental Commission, Congressman Norm Dicks and other interested government officials.
Coordinating Forum: In March 1991, EPA established a Coordinating Forum to facilitate
discussion and coordination among the various entities involved and/or affected by this project, and to
assist in the development and selection of a remedy that would be implementable in the
communities. The Forum met monthly from March 1991 through April 1992. The participants included
elected officials, key agency decision makers, management, and staff of various organizations
including:
Agency for Toxic Substances and Disease Registry
Asarco
City of Tacoma
Metropolitan Parks District
Puget Sound Air Pollution Control Authority
Tacoma-Pierce County Health Department .
Town of Ruston
Environmental Protection Agency
Washington Department of Ecology
Washington Department of Health
Washington Department of Labor and Industries
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In March 1992, the Coordinating Forum published preliminary findings regarding Community
Protection Measures (CPMs) associated with each cleanup alternative, and posed issues for
consideration in developing a preferred cleanup alternative. EPA continued to work with key
representatives of the Forum to develop the CPMs outlined in Section 9.10 of this ROD.
Real Estate Professionals
On June 18, 1992 EPA joined with Ecology, the City of Tacoma, and Town of Ruston to co-
sponsor a seminar on property transactions for realtors, appraisers, banking professionals and legal
counsel who conduct business in the Study Area. To publicize the event, EPA issued an open
invitation to a mailing list of those who had contacted the agency with questions and concerns.
Nearly 100 people attended the seminar. EPA presented information on its preliminary plans
for the cleanup, and on the issue of liability, and then opened the floor for discussions among the
professionals. EPA prepared a summary of the seminar for public information.
3.2 Education
Information Repositories: EPA has established ten repositories where citizens can review
detailed information about Superfund activities in the Tacoma area. Documents subject to public
comment can also be found in these locations. The repositories, frequently advertised in fact sheets
and in newspaper notices prepared by EPA, are listed in Table 1.
Fact Sheets and Brochures: Fact sheets and brochures have been prepared by EPA for
distribution to members of the community to provide current information on the status of site activities.
Table 2 includes a list of fact sheets and brochures published about the Study Area. Fact sheets
which exclusively discuss the ERA activities have been excluded.
4.0 SCOPE AND ROLE OF OPERABLE UNITS
The EPA has divided the CB N/T site into seven operable units (OU's) in order to facilitate the
investigation, analysis, and cleanup of this very large site. Four of these OU's are associated with the
Asarco smelter:
• OU 02 Asarco Tacoma Smelter
• 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 04 and primarily involves the cleanup of
arsenic and lead contaminated soils in the residential community surrounding the smelter.
4.1 Scope of Current Work
OU 04. Asarco Off-Property (Ruston/North Tacoma Study Area)
EPA believes that current conditions in the Study Area pose unacceptable risks over the long-
term to its current and future residents, and that cleanup actions are therefore necessary. EPA's goal
is to reduce potential exposures to arsenic and lead by physically removing contaminated soil to the
extent practicable. Removal of contaminated soil will also reduce the contaminants that are
transported into homes or other buildings.
EPA estimates that 273 acres of land including 525 residential Jots will require cleanup due to
the presence of lead and/or arsenic contaminated soil, and slag. The remedy selected in this ROB
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includes sampling of individual properties to determine if soil exceeds the action levels, excavation of
contaminated soil and slag, replacement of excavated soil and slag with clean soil and gravel, asphalt
capping or soil removal and replacement with gravel of contaminated dirt alleys and parking areas,
fencing and planting low lying shrubs in steep areas, and the development and implementation of
community protection measures. These actions will address the principal threat posed by conditions
at the site which is the ingestion of contaminated soil and dust.
The remedy selected in this ROD applies to those, properties or areas located within the Study
Area, as well as the three areas located directly to the south of the Study Area where sample results
show that soils exceed the action levels. Available data suggests that contamination above
background concentrations exists beyond the Study Area. It is possible that some additional
properties beyond the Study Area, particularly to the south-southwest, also have soils exceeding the
action levels and may require cleanup. EPA will evaluate the need for further sampling and
appropriate, cleanup activities outside of the Study Area separately from the current action, and at a
later date.
4.2 Other Related Activities
OU 02. Asarco Tacoma Smelter, and OU 07. Asarco Demolition
In September 1986, EPA and Asarco signed an Administrative Order on Consent under which
Asarco agreed to conduct investigation, analytical, and site stabilization activities at the smelter site
under EPA oversight. Site stabilization activities, including removal of some of the most contaminated
structures, were conducted by Asarco in 1986 and 1987. The investigation and analysis for the
cleanup of soil, surface water, and ground water at the smelter site is anticipated to be completed in
the Fall of 1993. Following completion of these activities, EPA will issue for public review and
comment a Proposed Plan for the cleanup of the smelter site.
In the meantime, Asarco is completing the demolition of remaining structures under a federal
Consent Decree with EPA signed in 1991. Demolition of remaining structures is expected to continue
through 1994-95. Also under this Consent Decree, Asarco installed controls on surface water that
runs onto the site to minimize the contact of surface water with contaminated soil.
OU 06. Asarco Sediments
EPA is analyzing cleanup options for contaminated marine sediments adjacent to the smelter
property. EPA anticipates releasing a Feasibility Study and a Proposed Plan, for public review and
comment, in the summer of 1993.
5.0 SITE CHARACTERISTICS
5.1 Sources of Contamination
Asarco smelter operations resulted in the deposition of arsenic, lead, and other contaminants
from smelter emissions to the surrounding areas. Soils in the community are currently contaminated
as the result of the accumulation of deposited materials over the operating history of the smelter.
Areas closest to the smelter have been most affected by various low-level fugitive1 emissions sources
from smelting operations. Areas at greater distances from the smelter have been most affected by tall
stack emissions.
1 Fugitive emissions are emissions from smelter processes that were not captured by a filter or
similar control system.
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In addition to the deposition of airborne contaminants released from the smelter, smelter slag
has been used at a number of locations in the surrounding community. Slag was produced as a by-
product of smelting operations. Typical uses of slag in the community include driveway, walkway, or
curbside aggregate, parking area surfacing, and backfill in utility trenches. No inventory of slag use in
the community is available.
5.2 Nature and Extent of Contamination
Based upon the results of previous investigations regarding the impacts of smelter operations
on the surrounding area, the Rl was designed to focus on the area most likely to require cleanup, on
soils as the primary environmental medium of concern, and on arsenic as the primary contaminant of
concern. The Rl was also designed to expand upon the existing information known about arsenic and
other contaminants in soils as presented in the FIR (see Section 2.0 for a brief discussion of the FIR)
and earlier soils studies.
During the Rl, ??? soil samples were collected to provide additional information on the
distribution of arsenic and other metals in surface and subsurface soils in the Study Area. Samples
were collected at three depths (surface, 6 to 1 0 inches, and 1 2 to 1 6 inches) at selected locations.
Samples were collected to fill data gaps, i.e., where little or no previous information existed, to
increase confidence in the arsenic distribution defined by previous FIR data, to provide information on
the vertical extent of arsenic contamination in soil, and to determine if arsenic was concentrated or
dispersed in areas such as gullies, parking lots, and alleys. Samples were collected from residential
properties as well as nonresidential areas including unpaved streets, alleys and parking lots, and
storm drains and ditches.
All soil samples collected during the Rl were analyzed for arsenic. In addition, selected
samples were analyzed for antimony, cadmium, copper, lead, mercury, and silver. This subset of
metals was selected for evaluation due to their previously identified high correlations, and their
presence in smelter feedstocks.2 Samples were also analyzed for physical parameters related to the
possible movement of arsenic in the environment including teachability, soil particle size, and pH.
Table 3 provides a summary of metals concentration data for residential surface and
subsurface soil samples. The table includes results for the combined Rl and FIR data sets. The soil
sampling results demonstrate the presence of metals above background concentrations in area soils,
(See sections 4.1 and 4.5 of the Rl for additional information on comparisons of sample results to
background concentrations.) As a result of an evaluation conducted in the EA, local urban
background concentrations for arsenic and lead have been characterized as 20 ppm and 250 ppm
respectively (see Section 2.0 for a description of the EA).
Arsenic and lead are the two contaminants of primary concern for human health (see Section
6.1 of this ROD). Therefore, the selection of action levels and the cleanup activities called for in this
ROD, are focused on arsenic and lead. Because the other metals identified above are generally found
at elevated concentrations at the same locations as arsenic and lead, cleanup measures to reduce
exposures to arsenic and lead will be effective in reducing exposures to the other metals.
The Rl study data indicates that there is an overall pattern of decreasing contaminant
concentrations with increasing distance from the smelter, with a directional component reflecting wind
patterns. Soil concentrations, however, vary from one property to another within the Study Area,
probably reflecting in large part human activities that have disturbed, surf ace soils. While soil
concentrations~generally decrease with depth, other patterns of arsenic distribution with depth were
also identified?^ general, these patterns were observed at locations where information suggested
that the soil had been disturbed. While the collection of soil samples for the Rl did not extend much
2 Smelter feedstocks are the raw copper-bearing material that was fed into the smelter.
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below a depth of one-foot, it is possible that contamination may exist deeper than one foot in some
areas.
Figures 3 and 4 identify the combined Rl and FIR soil sampling locations and concentrations
for arsenic and lead respectively. The data for arsenic are plotted on Figure 3 in the form of color-
coded symbols corresponding to the following concentration ranges: 0 to 46 ppm; 47 to 230 ppm;
231 to 400 ppm; 401 to 800 ppm; and greater than 800 ppm. These ranges were selected to illustrate
the wide range of arsenic concentrations found within the Study Area Approximately 81 percent of all
surface soil samples collected in the Study Area exceed 46 ppm. Approximately 34 percent of all soil
samples exceed 230 ppm - the arsenic action level selected in this ROD. Nineteen percent of all soil
samples exceed 400 ppm, and 5 percent exceed 800 ppm.
The highest levels of soil arsenic, i.e., above 800 ppm, occur within a small area near the
smelter property. Areas that are further away from the smelter generally show lower levels of both soil
arsenic and lead contamination. At these lower levels, much larger areas including greater distances
from the smelter are included. The area where impacts from the Asarco smelter can no longer be
detected in soil (i.e., where arsenic concentrations in soil would be within urban background levels of
20 ppm) is estimated to be well beyond the Study Area (see Section 4.3.1. of the Rl for further
information on the possible extent of contamination beyond the Study Area). It should be noted,
however, that some samples taken from within the Study Area were also below estimated urban
background levels for arsenic and lead.
Based upon consideration of all Rl and FIR soil data, and the selected action levels for arsenic
and lead, EPA estimates that 273 acres of land, including approximately 525 residential lots, may
require cleanup action. This includes driveway slag or slag of smaller size used for other purposes,
but would not include large pieces of ornamental slag. Estimated portions of the Study Area most
likely to require cleanup are shown in Figure 5.
5.3 Contaminant Migration
The results of the Rl indicate that samples from unpaved streets and alleys were generally
lower in arsenic content than residential surface soil samples taken in the same vicinity. Erosion, new
road base material, and vehicular tracking may account for redistribution of arsenic-bearing soil
particles and thus the lower arsenic concentrations in the unpaved street samples.
Historical studies through the 1970's and 1980's showed elevated contaminant concentrations
in multiple environmental media, including soils, house dusts, indoor and outdoor air, and garden
vegetables. Since copper smelting and arsenic processing ceased, ambient air concentrations have
been reduced by more than 90 percent. The remaining soil contamination, however, is likely to
continue to affect other media by contaminant transport and mobility, e.g., tracking of soil into houses
and releases of fugitive particulates to ambient air. The most important transport mechanisms of soil,
dust, and slag particles containing arsenic and lead appear to be through resuspension, redeposition,
and tracking. Therefore, the selected remedial actions (excavation of contaminated soil and
replacement with clean soil) will likely reduce contamination and potential exposures from other site
environmental media, e.g., house dust, over the long-term.
Based upon the results of the Rl, EPA has concluded that soil arsenic and lead are unlikely to
experience substantial leaching or downward movement in Study Area soils due to infiltration of water.
In addition, naturally occurring fate and transport processes appear unlikely to significantly reduce soil
arsenic or lead concentrations in the near term. Without remediation, or the altering (disturbing) of
soil, contaminant concentrations in soil are expected to remain at or near current levels for decades.
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5.4 Affected Population
The current and future residents of Ruston and North Tacoma, especially young children, are
the populations with potential exposures and health risks. The areas surrounding the Asarco smelter
have for some time been largely developed in single family residential land use. A sizable population
currently lives in the areas with soil concentrations exceeding background levels. An estimated 4,000
people live within a distance of approximately one mile from the smelter (roughly equivalent to the
area with soil arsenic concentrations at or above 100 ppm, but including some lower concentrations).
6.0 SITE RISKS
Operation of the Asarco smelter for a period of more than 90 years resulted in residual
contamination of the environment, particularly soils, in the surrounding areas of Ruston and North
Tacoma Potential exposures and health risks for current and future residents resulting from that
residual contamination were evaluated in a risk assessment. Children are of special concern because
their typical behaviors, like playing outdoors and various hand-to-mouth activities, may result in
exposure to soil contamination. Children are also particularly at risk for some effects of exposure to
metals, especially lead.
Risk assessment for a Superfund site is a four-step process. The first step, data collection
and evaluation, identifies the contaminants at the site. The second step, toxicity assessment, uses the
results of years of research and testing of the effects of chemicals on the health of people and
animals to decide which of the contaminants found at a site might pose a health threat. The third
step, exposure assessment, defines how people might contact the contaminants and how much of
the contaminant may enter their body. The final step, risk characterization, brings the information from
the first three steps together to determine the potential severity of health threats from the site.
The following sections provide a summary of the human health and ecological risk
assessments, as well as EPA's risk management decisions regarding the selection of remedial action
objectives and goals.
6.1 Identification of Contaminants of Concern
EPA evaluated metals which were known to be associated with the smelter (antimony,
cadmium, arsenic, copper, mercury, lead, selenium, silver, and zinc). Two were determined to be of
particular concern for human health: arsenic and lead. EPA determined that the other metals did not
individually pose significant risks to the community even at the highest levels detected in Study Area
soils.
6.2 Exposure Assessment
Six exposure scenarios were evaluated in the risk assessment: (1) ingestion of soils and
house dusts; (2) ingestion of garden vegetables grown in contaminated soils; (3) dermal contact with
contaminated soils; (4) inhalation of particles in the air, either outdoors or indoors; (5) ingestion of slag
and house dusts derived from slag; and (6) ingestion of soils and house dusts by a child with pica
(ingestion of abnormally high amounts of non-food substances, such as soil). The scenario of most
concern to EPA is the ingestion of soils and house dusts because it was estimated to result in the
highest potential exposures of'all of the scenarios evaluated. Several of these scenarios, for example,
pica soil ingestion, slag ingestion, and garden vegetable ingestion, would only apply to certain
residents.
For arsenic, site-specific data were combined with EPA's standard exposure assumptions
(e.g., living at a residence for 30-years) to estimate the amount of arsenic taken into the body on a
daily basis (the exposure). Exposures were estimated at five soil arsenic concentrations ranging from
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140 ppm to 1,600 ppm. These values represent a range of soil concentrations occurring in the Study
Area. Tables 4 and 5 summarize the exposure factors and the arsenic concentrations in each
exposure scenario for which exposures and risks were calculated. Tables 6 and 7 summarize the
amount of arsenic estimated to be taken into the body for the different exposure scenarios (media-
specific intake rates). The site-specific data used in the exposure assessment included:
• air monitoring data for arsenic at sites near the Asarco property boundary;
• soil data from the 1988 FIR;
• soil data from the Rl;
• slag data, including sampling of driveway slag and house dusts at three sites remote
from the smelter; and
• garden vegetable tissue concentrations from local studies to evaluate contaminant
uptake in relation to garden soil concentrations.
Typical background exposures to arsenic from normal diet, drinking water, and air sources
were compared to estimated exposures from contaminated community soils. Estimated exposures
from the more highly contaminated soils were several times greater than typical background
exposures.
For lead, possible childhood lead exposures were calculated using the 'LEAD4* model
developed by EPA. This model considers multiple potential pathways for childhood lead exposures
and predicts a distribution of blood lead levels for discrete age intervals. The exposure assumptions
used in the model are summarized in Table 8. Table 9 summarizes the amount of lead estimated to
be taken into the body (intake rate) at different soil tead concentrations ranging from 20 ppm to 2,700
ppm. These values represent a range of soil concentrations occurring in the Study Area.
6.3 Toxlcity Assessment
In the risk assessment, EPA evaluated the potential human health effects from exposure to
arsenic and lead. These effects are discussed below.
Arsenic
Both cancer and noncancer outcomes are associated with exposure to arsenic. Studies have
demonstrated that ingestion of arsenic is associated with an increased risk of skin cancer, and
inhalation of arsenic is associated with an increased risk of lung cancer. Estimated risks for these
types of cancer have been calculated by EPA. There is also evidence that ingestion of arsenic can
result in cancers of other organs (e.g., liver, lung, bladder, and kidney). These additional cancer risks,
however, were not calculated in the risk assessment because EPA has not adopted the necessary
information to estimate risks for these cancers.
Noncancer risks from the ingestion of arsenic include skin hyperpigmentation and skin
keratoses. At higher exposure levels, other possible noncancer effects include vascular, neurological,
and gastrointestinal disorders. Death from exposure to high environmental levels of arsenic (well
above those occurring at this site) has been documented.
Lead
Exposure to lead at elevated concentrations can affect many systems of the body. At lower
environmental concentrations, the primary concern is for learning and behavioral effects in young
children. The best indicator of lead exposure is lead levels in the blood. Recent studies show that IQ
and attention span effects can be correlated with slight increases in blood lead levels. Based on
these recent studies, acceptable childhood blood lead levels have been reduced to 10 micrograms of
lead per deciliter of blood (ug/dl). That blood lead level is used in the risk assessment as a value
against which to assess risks from lead exposures.
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6.4 Epidemiological Studies
Several health (epidemiological) studies on community residents living near the smelter have
been performed. These include studies to determine if lung cancer deaths or adverse effects on the
fetus (e.g., lower birth weight or birth defects) occurred at higher than normal levels in the community
due to smelter contaminants. These studies have not found statistically significant increases in
adverse health effects associated with arsenic exposures. This lack of observed health effects,
however, does not contradict EPA's risk assessment since the relatively low levels of risk of concern to
EPA would be difficult to observe or measure in community health studies. Further, no
epidemiological studies have been performed in the Study Area for the effects identified in the risk
assessment as being of greatest concern for ingested arsenic exposure - skin cancer and other skin
effects.
While not statistically significant, one lung cancer study of community residents did suggest a
possible arsenic relationship for lung cancers. The level of arsenic in the air in the community at the
time of exposure, however, was much higher than current levels, and therefore does not directly
contribute to understanding current risk estimates.
Urinary arsenic monitoring in the Ruston and North Tacoma area has been done periodically
since the early 1970's. The most recent scientifically designed survey conducted by the TPCHD in
1988 showed some significantly elevated values, although the average levels appear to have dropped
since closure of the smelter.
There are also no recent blood lead measurements in children from Ruston and North
Tacoma. The only available blood lead data, from the 1970's, reflects much higher automobile
emissions of lead from gasoline and generally higher urban air lead levels, and are not relevant to
current conditions.
6.5 Risk Characterization
Arsenic/Cancer Risk
Information on the toxicity of arsenic and the calculated exposures in the Study Area was
combined to estimate the skin and lung cancer risks for individuals living in the Study Area (see Tacie
10). Estimated risks will vary depending on the arsenic concentrations in individual yards. On Tab
10, risks at 800 ppm soil arsenic concentration are used as an example to show the reasonable
maximum exposure - the highest exposure reasonably expected to occur. Only 5 percent of the
Study Area is expected to have soil concentrations exceeding 800 ppm. Risks will be less for those
areas with lower soil arsenic concentrations.
Cancer risks for the air inhalation pathway represent risks of lung cancer. The cancer risks for
all other pathways represent skin cancer. The estimated air inhalation lung cancer risks are based on
monitoring data collected near the smelter property boundary. Lung cancer risks are expected to
decrease with increasing distance from the smelter. The highest risks for skin cancer result from the
ingestion of soil/house dust and slag/house dust. The skin cancer risks from the dermal absorption
and garden vegetable pathways are small in comparison. Pica behavior, as modeled in the risk
assessment, would result in approximately a doubling of skin cancer risk compared to the non-pica
individual.
Arsenic/Noncancer Risk
For noncancer effects, EPA develops a 'Hazard Quotient" to estimate the potential risks from
ingestion and dermal absorption of arsenic in Study Area soils (see Table 11). As the Hazard
Quotient rises above a value of T, the potential for noncancer effects increases.
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The dermal absorption and garden vegetable exposure pathways have hazard quotients
below 1.0, indicating no significant risks of noncancer outcomes (adverse skin effects). Potential soil .
and house dust exposures, as well as the case-specific exposures to slag and for a pica child, have
hazard quotients above 1.0 (ranging from 2.2 to 16.0) indicating the potential for adverse skin effects
in the exposed population.
Lead
The 'LEAD4* model was used to estimate the potential for a child to exceed a 10 ug/dl blood
lead level at various soil lead concentrations within the Study Area. Soil lead data is available from 41
locations within the Study Area (see Figure 4). The potential for a child to exceed a 10 ug/dl blood
lead level, based on the soil lead data, varied from 1 percent to 98 percent.
6.6 Uncertainty in the Risk Assessment
The risk assessment document includes a discussion of the uncertainties in the estimation of
exposures and risks. Since these risks are generally derived in a conservative manner, they have a
low likelihood of being underestimates. The actual risks could be lower than the estimates shown for
those effects considered in the risk assessment. However, as noted above in Section 6.3, other types
of cancer (liver, lung, bladder and kidney), for which no risk estimates have been derived, have been
associated with ingestipn of arsenic. Possible risks for these additional adverse effects may therefore
be in addition to those estimated in the risk assessment.
6.7 Potential Health Risks Exceed Acceptable Levels
As a general policy, EPA uses the results of the baseline risk assessment to determine if
remedial action is warranted at a Superfund site. According to the National Contingency Plan (NCP)
and EPA guidance, action under Superfund is generally warranted for cancer effects when the
baseline risk assessment indicates that an individual's excess lifetime cancer risk, using reasonable
maximum exposure assumptions exceeds 10"4.3 For noncancer effects, potential health risks
increase as the Hazard Quotient rises above 'r. For lead, EPA has determined that unacceptable
risks occur when an individual has greater than a 5 percent chance of exceeding a blood lead level of
10 ug/dl.
For both arsenic and lead, the estimated exposures and risks in the Study Area exceed those
levels that generally require remedial action at a Superfund site as defined by EPA in the NCP and
program guidance. Actual or threatened releases of hazardous substances from this site, if not
addressed by implementing the response action selected in this ROD, may present an imminent and
substantial endangermertt to public health, welfare, or the environment.
6.8 Remedial Action Objectives and Goals
The remedial action objectives and goals identified by EPA and included in Table 12 are
based upon the results of the risk assessment, and a number of other risk management
considerations including the scope, costs, and impact on the community of remedial actions, as well
as community acceptance of the remedy. Further information on how EPA considered these factors in
the selection of the action levels for the site can be found in EPA's January 1992 Ruston/North
Tacoma Site Preliminary Remedial Action Objectives Decision Memorandum.
3 EPA's acceptable risk range is defined in section 300.430(e)(2)(i) of the NCP as 10"4 to 10"6.
EPA guidance provides that "10^" can include estimated risks slightly above 1 x 10"4 if justified based
on site-specific information (Role of the Baseline Risk Assessment in. Superfund Remedy Selection
Decisions, OSWER Directive 9355.0-30, April 22, 1991).
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The remediation goals or action levels identified by EPA are 230 ppm for arsenic and 500 ppm
for lead. Properties or areas that exceed these action levels will require cleanup. The arsenic action
level of 230 ppm is based on reducing the additional potential skin cancer risk to no more than 5 in
10,000, within EPA's acceptable risk range for cancer causing chemicals.4 The 500 ppm action level
for lead is based upon a national goal of reducing levels in children's blood to no greater than 10
ug/dl, as well as EPA guidance that recommends establishing soil lead cleanup levels of 500 to 1,000
ppm.
In addition to being protective of human health and the environment, any final site remedy
must also comply with applicable or relevant and appropriate requirements (ARARs). The Washington
State MTCA cleanup standards are applicable requirements for the Ruston/Nlorth Tacoma site.
EPA has coordinated with Ecology in evaluating the MTCA requirements. Under MTCA
Method A, the soil cleanup levels for residential areas are 20 ppm for arsenic and 250 ppm for lead.
MTCA requires that some form of action be taken to address contamination above these levels. In
evaluating the available remedial actions to address contamination at this site, Ecology has
considered .the nature and extent of site contamination, the nature of human health risks, the exposure
pathways, and the potential impacts and costs associated with physical remediation activities in the
community. Ecology concluded that the EPA action level of 230 ppm for soil arsenic represents a
best balancing of factors for a level at which engineering actions (e.g., soil removal) for remediation
should begin at this site. For lead, Ecology can elect to use the conservative Method A cleanup level
of 250 ppm, or it can use site-specific information and the latest version of EPA's biokinetic model to
establish a cleanup level (see WAC 173-340-702(6)). Ecology has determined that the results of
applying the 'LEAD4' model support setting the soil lead cleanup level under MTCA at 500 ppm for
this site.
CPMs (discussed further in Sections 7.0 and 9.10) will be used to address the residual risk
presented by soils which have arsenic concentrations between the MTCA cleanup level of 20 ppm and
the EPA action level of 230 ppm.
6.9 Environmental Risks
The approach used in the ecological risk evaluation (Technical Memorandum: Ecological Risk
Evaluation, EPA, July 1992) was to compare site-specific soil concentrations with data from scientific
literature. The few available site-specific ecological studies were considered, but differences in site
conditions during and after smelter operations limited the application of those results.
The primary contaminants of concern for potential ecological effects in .the Study Area were
identified as arsenic, copper, and lead. Soil, plants, invertebrates (earthworms and insects), small
mammals, birds, and pets (e.g., dogs and cats) were considered in the evaluation.
Current soil contaminant concentrations in the Study Area appear likely to cause adverse
effects on some plants and soil invertebrates. Small mammals and birds feeding on soil invertebrates
could also have elevated tissue levels of the contaminants of concern. Based on a simplified
exposure and risk assessment, small mammals in the most contaminated parts of the site could
experience adverse health effects. Larger mammals, including pets such as dogs, are not anticipated
to be at substantial risk from potential exposures to soil contaminants. Uncertainties in the extent,
severity, duration, and significance of possible adverse ecological effects at this site are relatively high
because of the lack of site-specific studies.
4 EPA's 'Ruston/North Tacoma Site Preliminary Remedial Action Objectives Decision
Memorandum" documented why an action level correspondfng to a 5-x 10"4 level was warranted
based on site-specific considerations.
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Copper is typically a contaminant of concern in ecological risk studies. The human health risk
assessment, however, identified only arsenic and lead as the contaminants of primary concern. Action
levels for arsenic and lead have been identified by EPA (see Section 6.8). Although there is no risk-
based action level for copper, copper has been shown to be highly correlated with arsenic and other
smelter-related metals in Study Area soils, reflecting the significance of smelter emissions as a source
of these metals. As a result, remediation for arsenic and lead would also address most areas of
elevated copper concentrations.
It is possible that there could be some ecological effects associated with remaining soil
contamination after the cleanup. Such effects, if any, are likely to be relatively subtle and limited in
magnitude. Other factors related to typical urban activities and land use changes could also effect
plants and animals in the Study Area Any ecological effects from residual contamination below the
action levels may be difficult to distinguish from the effects of these other factors.
EPA has considered the information in the ecological risk evaluation in selecting action levels
for site soils. It appears likely that the selected action levels for human health would also reduce
potential ecological effects to levels that are, at worst, relatively hard to detect and of little
consequence given the existing effects of urban land uses throughout the Study Area. Therefore, the
selected action levels were determined to be adequately protective of ecological risks at the site.
7.0 DESCRIPTION OF ALTERNATIVES
In the FS, EPA developed and considered six alternatives for cleanup of soils contaminated as
a result of emissions from the Asarco smelter. The FS alternatives included varying degrees of
cleanup activities that would apply to residential lawns, garden areas, commercial properties, open
park lands, empty lots, unpaved streets and alleys, and other exposed soil surfaces or areas where
arsenic and/or lead concentrations exceed EPA's cleanup goals.
EPA's Preferred Alternative, described and issued with the Proposed Plan, combined elements
from several of the six FS alternatives. EPA considered several general principles and guidelines (see
section 7.8) when deciding upon the Preferred Alternative. The Preferred Alternative was presented as
the best balance of benefits and tradeoffs for the Ruston/North Tacoma community for consideration
during public comment. The Preferred Alternative has since been further modified by public comment.
Except for the 'No Action* alternative, the cleanup alternatives were designed to reduce
exposure to contaminated soil and dust, as well as to reduce, the potential transport of soil
contaminants inside homes and other buildings. While EPA believes that the cleanup action must
reduce the likelihood of exposure to contaminated soil, it is also important that residents enjoy the
fullest use of their properties.
While not discussed in the soil cleanup alternatives listed below, cleanup activities would also
include the remediation of slag from driveways, and from other areas within the Study Area where slag
use could lead to potential human exposures. In areas where slag is removed, it would be replaced
with gravel.
During the technology screening process conducted as part of the FS, EPA considered a
range of treatment options and conducted a soil washing treatability study. The results of the
screening process and the treatability study indicated that treatment is neither practical nor effective in
reducing contamination levels. Treatment alternatives, therefore, were dropped from further
consideration.
In addition, each alternative with the exception of 'No Action* includes provisions for
implementing community protection measures within the Study Area..Community protection measures
(described below) were deemed necessary for any alternative under which contaminated soil would
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be left in place. This includes areas where arsenic remains in soil in concentrations above the action
level, (e.g., below a soil cap or paved road), as well as areas where arsenic and lead exceed
concentrations normally found in urban areas, but are below the action levels.
The following section describes the six FS alternatives, the common components of the
alternatives, the general principles and guidelines that guided EPA in composing the Preferred
Alternative, as well as a description of the Preferred Alternative. Tables 13 and 14 provide a
comparative summary of the alternatives.
7.1 Alternative 1 - No Action
The No Action alternative is required by law to be evaluated and provides a baseline for
comparison against other alternatives. Under this alternative, there are no physical remediation
activities or community protection measures. Because no remedial activities would be implemented,
there would be no reduction in the current potential risks from exposure to residential soils and dust,
i.e., risks would be essentially the same as those identified in the baseline risk assessment.
Total Estimated Present Worth Cost None
Estimated Time to Complete Not Applicable
7.2 Common Components of the Alternatives
Except for the No Action alternative, all of the remaining alternatives have some components
in common. These components are described below and are not repeated in the discussions of each
alternative.
a. Common Components of Alternatives 3 through 6 and the Preferred Alternative
Extent of Remediation
Soil removal or containment activities at properties or areas that exceed EPA's action levels
generally would address sod areas (residential and commercial), landscaped areas, garden areas,
unpaved driveways, and roadway shoulders. A "marker,1 e.g., a porous geotextile or geocomposite
material, would be placed at the base of the excavation to demarcate for future intrusions the
maximum depth of the excavation. Excavated soil would be replaced with 'clean* soil, i.e., soil with
concentrations of arsenic less than 20 ppm and lead less than 250 ppm. Even lower values for the
replacement soils, especially for lead, are likely achievable, e.g., lead less than 100 ppm. Soil would
not be removed from beneath sidewalks, driveways, streets, or other paved areas.
Dirt alleys and parking areas where soils exceed the action levels would be paved with asphalt
to provide an impermeable barrier to contamination. The total area to be covered with asphalt was
estimated, with the use of aerial photographs and site visits, to be about 5 percent of the total site
Study Area (approximately 14 acres). This area is based upon the assumption that all din alleys and
unpaved areas contain soil lead and arsenic at concentrations above action levels and therefore
require remediation.
Steeply sloped areas (see Figure 6) which could not be capped with asphalt, graveled, or
sodded would be fenced and planted with low-lying shrubs. A geotextile fabric would be used to aid
in the growth and development of natural vegetation, as well as in the reduction of erosion.
Vegetation Removal and Replacement
The lawn areas of remediated yards would be revegetated with sod and maintained to ensure
that the grass cover is well established. To the extent possible, yard.landscaping would be returned
to its original condition. Sod and any fertilizer would be applied by a landscape contractor using -
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conventional construction equipment. Shrubs and other types of groundcover would be planted by
hand (see Section 9.10 (c) below for information on cap maintenance procedures).
Reasonable attempts, which do not hinder the progress of the remediation and are not
excessively costly, would be made to accommodate owners who wish to retain original landscaping.
The actual vegetation removal and replacement plan would be determined on a property-by-property
basis in conjunction with the property owners.
Safety Measures During Remediation
During implementation of the cleanup, safety measures would include, at a minimum, the use
of health and safety monitoring equipment and personal protection gear, the use of dust suppression
techniques during excavation activities, lining and covering truck beds when transporting
contaminated materials, removing soils from truck wheels before trucks travel on public roads, the
establishment of local truck routes to minimize disruption to the community, provisions for road
maintenance and repair if improper measures (e.g., excess loads) result in damage to roads, and
covering of any stockpiled materials.
Disposal
Under current state law (Dangerous Waste Regulations), removed soil with arsenic
concentrations greater than 100 ppm is considered a dangerous waste and requires disposal at a
hazardous waste facility. There are no such facilities available in the state of Washington at this time.
The Department of Ecology is currently evaluating a petition by Asarco to exempt residential soils from
the disposal criteria in the Dangerous Waste Regulations. If approved, additional disposal options
could become available in the future. EPA, therefore, considered several possible disposal options in
the FS including an out-of-state non-hazardous waste facility operated by Finley Suites Landfill
Company in Arlington, Oregon, an out-of-state Class I hazardous waste facility in Arlington, Oregon
owned by Chemical Waste Management, Inc., and disposal on the Asarco smelter property.5
The facilities described above were examined as part of the cost estimating process to provide
a range of potential disposal fees. For those alternatives where a range of costs is shown, the lower
costs reflect disposal of contaminated soil at a nonhazardous waste facility, and the higher costs
indicate disposal at a hazardous waste facility. All of the alternatives, except for 4a, assume final
disposal of contaminated soil at a facility outside of the residential Study Area. Alternative 4a includes
disposal on the Asarco smelter property.
Shrubs and other yard waste removed during the remedial action are not expected to be of
significant concern due to low arsenic and lead levels. The inclusion of contaminated soils with
vegetation during the digging and clearing for remedial actions may be of greater concern than actual
plant tissue uptake of arsenic and lead. This waste could be disposed in a municipal solid waste
facility within the State of Washington, or routed to the Tacoma urban composting facility, if
determined to have minimal concentrations of contaminants.
5 A determination to dispose of Study Area soils on the smelter property cannot be made in this
ROD. An evaluation of the viability of disposing of Study Area soils on the smelter property is being
conducted as part of the smelter cleanup process. EPA will seek further public review and comment
on this issue when the Proposed Plan for cleanup of the smelter property is issued.
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b. Common Component of Alternatives 2 through 6 and the Preferred Alternative
Community Protection Measures
Community protection measures, commonly referred to as institutional controls, are non-
engineering measures used to prevent or limit public exposure to soil contamination. These measures
could be used as the sole component of remediation (to prevent or minimize exposure to
contaminated soil), or in conjunction with an engineering action (to ensure that the technology is
implemented and remains effective). Alternative 2 relies upon community protection measures as the
sole remediation component. Varying degrees of community protection measures would be
necessary for alternatives 3 through 6 and the Preferred Alternative to the extent that contaminated
soil is not removed from individual properties. The objectives for community protection measures for
the Ruston/North Tacoma site were defined as follows:
• To control activities that intentionally disturb contaminated soils by providing
guidelines or permit requirements for conducting those activities with the minimum
amount of contact with or movement of contaminated soil.
• To ensure the long-term integrity of caps (soil, sod, and asphalt) used in the
alternatives by providing for maintenance, repair, and inspection of any capped areas.
* To establish a post-cleanup storage/disposal program for contaminated soil.
• To provide a means for notifying potential future property owners if contaminated soil
remains at a property, and inform them of the above guidelines and responsibilities.
• To educate the community over the long-term on the above guidelines and
responsibilities.
The possible community protection measures, which could be used to meet the objectives
identified above, were described and evaluated in the FS and are listed below:
• . Development of Policy and Planning Documents
• Land Use and Development Regulations
• Special Legislation
• Real Property Restrictions
• Contractual Agreements with Individuals
• Contractual Agreements with Potentially Responsible Parties (PRPs)
• Public Education and Public Involvement
The effective implementation of community protection measures relies upon the cooperation
and involvement of the community and the local officials. Accordingly, the specific community
protection measures included in the selected remedy (see Section 9.10) were identified following
significant input from the Ruston/North Tacoma Coordinating Forum, the Ruston/North Tacoma
Community Workgroup, and public comments given or submitted during two public comment periods
associated with the RI/FS and the Proposed Plan.
7.3 Alternative 2 - Limited Action
The ed action alternative would rely solely upon the community protection measures
described in ction 7.2b to reduce exposure to contaminants and to achieve the remedial action
objectives. -;n measures would include controlling soil disturbances, establishing a soil disposal
program, notifying future property owners if contamination exists, and implementing public education
programs to inform residents on how they can reduce their exposure to contaminated.soil.
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Total Estimated Present Worth Cost $3 million
Estimated Time to Complete Ongoing and Indefinite
7.4 Alternative 3 - Containment of Contaminated Soil
The containment alternative focuses on containing contaminated soil by covering lawns, parks,
and other areas of exposed soil with sod, by covering dirt alleys and parking areas with asphalt, and
by implementing the community protection measures program identified in Alternative 2.
The implementation of this alternative would involve tilling of existing soil and grass with a
rototiller to a depth of about 6 inches. This tilled material would form the subsoil or base for the new
sod. Most trees and shrubs would remain undisturbed; only very small vegetation would be removed
during the remedial action. In some cases, where existing soil was deemed inadequate to support
new sod, additional sandy loam would be applied to form a 2 inch lift. The application of this
additional soil would therefore require the removal of an equivalent volume of original soil to maintain
original grade. This excavated material would constitute a remedial action by-product which would
require disposal.
The subsoil would be prepared (raked and rolled) and covered with a new, clean, 1 inch sod
layer. The placement of 1 inch of clean sod may enhance the risk reduction aspect of this alternative
over merely applying seed to existing soil. The application of sod would result in a negligible positive
change in the grade of each lot. Each home lot (approximate size
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Implementation of this alternative would result in over 187,000 cubic yards of contaminated
soil which would require disposal. Approximately 7 years would be required to complete the soil
excavation, removal, and replacement at the site. This estimate was based upon a 10-month work
year with 20 work days per month. The average remediation rate would be about eight homes per
month at 140 cubic yards/day, using seven 35 cubic yard dump trailers per day (actual load capacity
20 cubic yards).
Contaminated soil would be transported to the Asarco facility for storage in a secure area of
the site where access could be controlled. Soil would be stored at the Asarco facility until a
determination is made regarding the viability of containing the soil on-site. Asarco is evaluating on-site
disposal as part of the smelter facility RI/FS for waste associated with smelter demolition and smelter
site cleanup. A final determination regarding on-site disposal will not be made until the ROD for the
smelter property cleanup is signed. This decision is expected within the next year. Therefore, it is
possible that under this alternative soil may be stored on-site for a lengthy period of time.
There are several possibilities for the temporary storage of contaminated soil from the
residential area on the smelter site. The total Asarco site covers approximately 67 acres. About 40
acres are covered by structures which will be demolished in accordance with the December 1990
Demolition Record of Decision. In addition, some storage capacity exists in the fine ore bins building,
which currently contains soil removed during the ERAs.
As pan of the smelter facility RI/FS, and in order to fully evaluate the possibility of disposal at
the Asarco facility, Asarco has prepared a containment facility siting report. This report identified
potential locations within the Asarco smelter property that could be modified for use as a permanent
disposal facility for excavated soil and debris. On-site containment has been evaluated primarily for
the disposal of debris from stack demolition and other demolition and cleanup activities on the smelter
site.
EPA and Asarco have discussed possible disposal options for excavated residential soils
including disposal on the smelter site. Modifications to the preliminary designs for on-site disposal
could result in additional capacity to accommodate residential soil. EPA and Asarco agree that
determining the viability of this option depends to a large extent on a more specific estimate of soil
and demolition debris to be removed, and upon the hazardous waste classification of the materials
(residential soil and smelter site soil and debris) to be disposed. Because this classification and final
volume estimates have not yet been established, it is difficult to obtain accurate detailed cost
estimates for on-site disposal at this time. In addition, because the option of disposing of residential
soil on-site is presently in a conceptual stage, and specific design criteria have not been established,
it is difficult to make accurate predictions regarding the configuration of a disposal facility and its
capacity.
4a Temporary Storage and Permanent Disposal at Asarco Smelter Facility
Total Estimated Present Worth Cost $43 to $56 million
Estimated Time to Complete 7 Years
4b Temporary Storage at Asarco Smelter Facility Followed by Permanent Disposal at Appropriate
Off-site Facility
Total Estimated Present Worth Cost $67 to $87 million
Estimated Time to Complete 7 Years
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7.6 Alternative 5 • Excavate 1 Foot of Soil/Backfill/Disposal
This alternative is identical to Alternative 4 except that excavated soil would be shipped
directly off-site for disposal at a permitted landfill. The disposal options evaluated for this alternative
are identical to those discussed in Alternative 3.
. Significant differences between this alternative and Alternative 4 include a potential substantial
increase in soil transportation distances and the elimination of an indefinite period of temporary soil
storage. This alternative would incorporate the same elements of soil removal, transportation,
backfilling and revegetation as described for Alternative 4.
Total Estimated Present Worth Cost $61 to 82 million
Estimated Time to Complete 7 Years
7.7 Alternative 6 - Excavate to Depth at Which Background Contaminant Levels Are
Achleved/Backfill/Dlsposal
This alternative is identical to Alternatives 4 and 5 except for the following - at properties or
areas that exceed the action levels, excavation would proceed to a depth until background
concentrations of arsenic and lead (20 ppm arsenic and 250 ppm lead) are achieved. Current data
indicate that soil lead and arsenic concentrations are highly variable with depth throughout the Study
Area. In addition, Rl soil samples were not collected from depths greater than 16 inches, and
therefore, it is not possible to accurately predict the distribution of contaminants below this depth.
Additional field sampling during the remedial design phase would be necessary on a site-by-site basis
to accurately define the depth of contamination prior to excavation.
Despite these limitations, estimates of the required depth of excavation were made to provide
a basis for the development of this alternative. Depth profile data were not available for lead; however,
the statistically significant linear correlation between lead and arsenic in surface soils provides a
measure of assurance that similar trends for arsenic and lead over depth may be evident and,
therefore, the arsenic profile data alone are adequate for conceptual estimates.
The conceptual excavation, design, and thus the cost estimate for this alternative, were based
upon certain assumptions made in the FS regarding likely contamination levels at depth (see the FS
Section 3.1.6 for further information). These assumptions represent the interpretation and application
of a relatively limited set of subsurface soil data. Therefore, the assumptions and the estimates derived
from the data would change and undergo refinement during the remedial design stage if Alternative 6
was selected.
The total volume of material which may require excavation and removal under this alternative
is 341,000 cubic yards. Significant differences between this Alternative and Alternatives 4 and 5
include a substantial increase in the volume of soil, and the possibility of damage to some structures
due to deep excavation, and the possibility that some residents may need to be relocated temporarily
during excavation operations.
Relocation periods are expected to be very short, possibly no more than a few days for each
resident affected and not all residents would be affected. Relocation may be necessary to ensure the
safety of residents should construction activities become so extensive that the foundations of buildings
are damaged or utilities services are interrupted. Other factors which may affect decisions for
relocation include noise levels during remediation and limitations on access to residences. This
alternative would incorporate the same elements of soil removal, transportation, and backfilling and
revegetation as described for Alternatives 4 and 5.
CPMs for individual properties would generally not be required once remediation was
complete since no contamination above background concentrations would remain. However,
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community protection measures would be required for any areas where excavation has not occurred
(e.g., under roads and sidewalks and within steeply sloped areas), and where practices such as utility
repair and maintenance would be conducted in unremediated areas.
Because the total volume of material to be excavated and the rate of excavation will not be
determined until the design phase, it is not possible to precisely calculate the time to complete this
alternative. However, based upon a 10 month work year with twenty work days per month the
average remediation rate would be about four homes per month at 140 cubic yards/day using seven
35 cubic yard dump trailers per day (actual load capacity 20 cubic yards). Thus, approximately 12
years would be required to complete the soil excavation, removal and replacement at the site.
Total Estimated Present Worth Cost $85 to 119 million
Estimated Time to Complete 12 Years
7.8 General Principles and Guidelines
The nine criteria described in Section 8.0 of this ROD are the framework that EPA used to
evaluate benefits and tradeoffs among the range of FS alternatives in order to define the Preferred
Alternative (described below) and to select the final remedy described in Section 9.0. Some of the
balancing and modifying criteria are emphasized more than others depending on the specific
conditions or problems at an individual site. Based on comments received from Study Area residents
during the first public comment period, the following principles and guidelines represent features that
are important to the community if a significant cleanup action is to be implemented:
(1) Remove contaminated soil from properties or areas which exceed EPA's action levels of 230
ppm arsenic and 500 ppm lead.
(2) Minimize the need for long-term legal or administrative measures on individual properties
(e.g., cap maintenance requirements).
(3) Reduce uncertainties for homeowners by (a/ sampling individual properties and (b) plannin.
for homeowner involvement in the cleanup process.
(4) Reduce the cleanup time frame to the shortest duration possible.
(5) Minimize disruption to the community during cleanup. Schedule cleanup activities to fit
within daily community routines to the extent possible. Use safety measures during cleanup to protect
residents and workers.
7.9 The Preferred Alternative
The Preferred Alternative combined several elements of the alternatives described and
evaluated in the FS. Below is a description of the Preferred Alternative, followed by a discussion of
how it compares to the alternatives presented in the FS as discussed above.
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Description of the Preferred Alternative
The Preferred Alternative calls for excavation of soils from properties or areas that exceed
EPA's action levels for arsenic and lead. Excavated areas would be filled with clean soil and re-
landscaped. In order to determine the specific areas requiring cleanup, each property within the area
most likely to exceed action levels (see Figure 5) would be sampled. Other locations within the Study
Area would be sampled as needed or as requested by the property owner. The majority of properties
requiring cleanup can be cleaned completely (i.e., soil above the action levels will not remain),
therefore eliminating the need for long-term controls on many private properties.
Soil which exceeds action levels below 18 inches would not be excavated. In cases where
sampling shows that soil above action levels exists below 18 inches, 18 inches of contaminated soil
would be removed and replaced with clean soil, and a maintenance and monitoring program for the
capped area would be established. The purpose of this program would be to ensure that clean soil
remains in place to cover any remaining areas where soil concentrations exceed action levels. It
would also ensure that if contaminated soil is excavated in the future for development or other
reasons, proper safety procedures are followed. In addition, a post-cleanup soil collection and
disposal program would be established to provide a place for disposal of any remaining soil
contaminated above action levels that may be excavated from beneath a clean soil cap for
development or other purposes.
Excavated soil would be disposed at an appropriate facility outside of the residential Study
Area An interim staging area or transfer station, however, may be needed in the community or on the
smelter site during cleanup activities.
Other elements of the Preferred Alternative include: asphalt capping of contaminated alleys
and right-of-ways; development of educational materials for Study Area residents; and removal of slag
driveways.
Total Estimated Present Worth Cost $60 to 80 million
Estimated Time to Complete 7 Years
Comparison of Preferred Alternative to FS Alternatives
The element of Alternative 6 that was retained in the Preferred Alternative was the emphasis
on removal of contaminated soil so that the need for long-term legal or administrative measures on
individual properties after the cleanup - including requirements for maintaining a soil cap - can be
significantly reduced throughout the Study Area. Alternative 6 provided that if all soil at depth above
levels commonly found in urban areas (20 ppm arsenic) was removed, long-term measures on
individual properties would not be required.
If an exemption to the State Dangerous Waste Regulations is granted (see section 7.2 a.
above), long-term measures on individual properties will not be necessary if soil at a property or area
above EPA's action levels (e.g., 230 ppm arsenic) is removed. Therefore, since the Preferred
Alternative involves removal of soil above action levels, it provides the same benefit of Alternative 6 in
terms of significantly reducing the need for long-term measures on individual properties after the
cleanup, but the Preferred Alternative will not require nearly as much soil removal as Alternative 6.
Further, because the Preferred Alternative includes sampling of individual properties before a
cleanup is conducted, it allows for flexibility in determining the depth to which contaminated soil would
be removed. Contaminated soil would be removed only to the depth necessary as indicated by
sampling. For example, if sampling shows that soil contamination above action levels exists to 6
inches below the surface, it would only be necessary to remove soil to a depth of 6 inches. Based on
existing soil samples, EPA believes that the majority of properties would require excavation only within
6 inches of the surface.
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The Preferred Alternative is similar to Alternatives 4 and 5 in that it includes a practicable limit
on the depth of excavation at individual properties. Alternatives 4 and 5 required excavation to a
depth of 1 foot at each property (Alternative 6 had no limits on the depth of excavation). The
Preferred Alternative would limit excavation to a maximum depth of approximately 18 inches.
8.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
The alternatives outlined in Section 7.0 were evaluated using each of the nine evaluation
criteria as required by the National Contingency Plan, and described in Table 15. The purpose of this
evaluation was to identify the advantages, disadvantages, and relative tradeoffs among the
alternatives. While all nine criteria are important, they are weighted differently in the decision-making
process. Threshold criteria are used to determine whether an alternative meets a required level of
performance. Primary balancing criteria are used to evaluate technical, economic, and practical
realities, and modifying criteria require consideration of state and community concerns.
The following is a discussion of the evaluation of the nine criteria for each of the remedial
alternatives. The No Action alternative does not meet the two threshold criteria and therefore is not
addressed further in this section.
Threshold Criteria
8.1 Overall Protection of Human Health and the Environment
The key factor in evaluating the overall protection provided by each of the alternatives,
including the Preferred Alternative, is the extent to which an individual's exposure to contaminated soil
is reduced or eliminated. A general summary of EPA's range of cleanup alternatives demonstrates the
varying approaches to achieving protectiveness including:
• using administrative/legal measures to prevent or minimize individual contact with
contaminated soil, and to reduce risk where contact does occur (Alternative 2);
• specifying placement of a sod cover over contaminated soil to act as a barrier
between an individual and the soil (Alternative 3);
• requiring removal of one foot of contaminated soil with a soil cap to isolate
contaminated soil (Alternatives 4 and 5);
• requiring removal of soil from properties or areas above action levels to a maximum
depth of 18 inches (the Preferred Alternative); and,
• requiring removal of soil from properties or areas above action levels to a depth at
which background levels are achieved, except under structures or roadways
(Alternative 6).
Each of these alternatives provides protection by either reducing exposure to contaminants or
removing the contaminants, but differ in several significant respects, for example, the extent to which
protectiveness can be maintained over the long-term (see Section 8.3 below). Differences among
alternatives are examined under each of the remaining criteria.
8.2 Compliance with Federal and State Environmental Standards
All of the alternatives (except Alternative 2 - Limited Action) would comply with ARARs under
federal or state environmental laws for the site. Table 16 lists the. ARARs for the alternatives that were
considered.
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Alternative 2 appears to be inconsistent with both EPA's expectation and Ecology's
requirement that limited action, or an action that relies solely on institutional controls such as
community protection measures, should not substitute for more active measures (or a higher
preference cleanup technology under MTCA) unless such active measures are found to be
impractical. EPA and Ecology have determined that both (1) the physical removal of contaminated
soil to a certain depth, and/or (2) the capping of contaminated soil is practicable and technically
possible in the Study Area
Requirements for an appropriate off-site facility for the disposal of contaminated soil will be
described in Ecology's final decision on Asarco's petition to exempt residential soils from the Ruston
and Tacoma area from disposal in a hazardous waste facility.
The requirements for hazardous waste under the Resource Conservation and Recovery Act
(RCRA) are not applicable or relevant and appropriate for the Study Area cleanup because the soil
and slag to be disposed are not hazardous waste.6 Based on soil samples taken during the Rl, the
soil does not exhibit the toxicity characteristic under 40 C.F.R. § 261.24 or any other characteristic
under 40 C.F.R. Subpart C. Slag is not regulated as a hazardous waste under 40 C.F.R. § 261.4(b)(7).
Balancing Criteria
8.3 Long-Term Effectiveness and Permanence
The long-term effectiveness of an alternative corresponds directly to the extent to which
contaminated soil is removed under that alternative due to the potential for disturbance and re-
exposure. The alternatives that rely on containment of contaminated soil and community protection
measures (without soil removal) are not likely to be as effective over the long-term as removal of
contaminated soil because the continued enforcement, awareness, and acceptance of such measures
by government agencies and Study Area residents cannot be guaranteed.
Alternative 6 is the most effective over the long-term in terms of reducing risk to human health.
The excavation of soil at depth contaminated above background levels (20 ppm arsenic and 250 ppm
lead) would essentially ensure that all risks due to contact with contaminated soil above EPA's action
levels would be minimized. Even under Alternative 6, however, some contaminated soil above EPA's
action levels may remain under hard surfaces, such as roadways, houses, and buildings, or in steeply
sloped areas.
The Preferred Alternative offers the next most comprehensive level of long-term protection
because it would cleanup, to a maximum depth of 18 inches, most of the properties or areas that
exceed action levels. A clean cover of soil would be installed, and cap maintenance measures would
be established, where soils over the action levels are left below the cover. Based on current depth
profile sampling data (to a depth of 16-inches), EPA estimates that only a small percentage of
properties would have contamination remaining below 18 inches.
Alternatives 4 and 5 are the next most effective over the long-term because they would require
excavation of soil to a depth of 12 inches at properties or areas that exceed EPA's action levels. A
clean cover of 12-inches of soil would be installed and cap maintenance measures would be
established where soils over the action levels are left below the cover.
The Preferred Alternative and Alternatives 3, 4 and 5 also call for a soil testing, removal and
collection program for the Ruston/North Tacoma residents if soil areas above EPA's action levels need
6 Under Washington state's Dangerous Waste Regulations (Chapter 173-303 WAC), removed soil
or slag with arsenic concentrations greater than 100 ppm is considered dangerous waste (see Section
7.2.a for information on the petition for exemption from the Dangerous Waste Regulations)-.
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to be excavated after the cap is in place, for example during remodeling activities that require
excavation of soil below the cap.
Alternative 3 is less effective than 4, 5, 6 and the Preferred Alternative because it involves very
little removal of contaminated soil. Typical use of a yard could penetrate or degrade the sod barrier,
exposing contaminated soil. Alternative 3 is more protective over the long-term than Alternative 2,
however, because placing a new sod barrier would reduce potential exposure to contaminated soil at
least to some extent.
Alternative 2 would provide the least protection over the long-term because it would not
provide for either a comprehensive removal of contaminated soil or a physical barrier against
contaminated soil. Its success would depend upon the sustained acceptance, understanding, and
participation of the community in the community protection measures programs. Alternative 2 also
provides for a soil disposal program for individual disturbances of contaminated soil.
8.4 Reduction of Toxictty, Mobility, or Volume through Treatment
None of the alternatives provide for treatment of contaminated soil. Although soil washing was
considered the most viable treatment alternative for the Ruston/North Tacoma soils, it was determined
that further consideration of soil washing was not justified based on the results of a Treatability Study"
(Fractionation and Soil Washing of Ruston/North Tacoma Soils, EPA, November 1991). The study
showed that soil washing was not consistently effective at reducing the concentrations of
contaminants to protective levels.
8.5 Short-Term Effectiveness
The potential for short-term risks and exposures, e.g., inhalation of contaminants by workers or
residents because of dust and particles generated by movement of soil, and increased traffic in the
community, are directly related to the extent of soil excavation required by each of the alternatives,
including the Preferred Alternative. Alternative 6 would potentially present the most significant short-
term exposures because more extensive soil removal would be required than under any other
alternative. Short-term risks are potentially less of a problem under Alternatives 2 and 3 because
extensive soil removal is not required.
Short term risks and exposures can be minimized because dust control and safety measures,
including air monitoring, would be required during excavation. Also truck beds would be lined and
covered when transporting contaminated materials, truck wheels would be cleaned before travelling
on public roads, and local truck routes would be established to minimize disruption to the community.
The Preferred Alternative would require that local roads used for transporting contaminated soils be
regularly inspected and repaired if damage occurs due to improper use when implementing the
remedy. In addition, trucks would be expected to use common safety precautions (e.g., brake
inspections). Also, rail transportation of contaminated soil may be an acceptable alternative to trucks.
An analysis of short-term effectiveness includes an evaluation of the time necessary to
complete cleanup activities under an alternative. Although short term risks to the community under
Alternative 2 would be low, the community protection measures program under this alternative would
be ongoing indefinitely throughout the entire community.7 Alternative 3 would involve both minimal
short-term risks because extensive soil excavation is not required, and because of the relatively short
time frame to complete its activities - perhaps 1 year to complete sodding replacement activities.
7 Some form of community protection measures program would be necessary for all of the
alternatives. Since the primary purpose of the program is to address contaminated soils that remain
in the community after the cleanup, the scope and duration of the program will be more substantial
when less soil is removed from the Study Area.
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Alternatives 4, 5, and the Preferred Alternative are generally similar in terms of their short-term
effectiveness, although the Preferred Alternative may be advantageous because it allows for varying
depths of excavation based on soil depth profiles (Alternatives 4 and 5 require that all contaminated
soils be removed to a 12 inch depth). Short-term risks and exposures are potentially greater for
Alternative 6 because removal of more soil increases the possibility for damaging utilities and other
structures. Also, Alternative 6 may require almost twice as much time to complete as Alternatives 4, 5,
or the Preferred Alternative.
8.6 Implementabillty
All alternatives are technically feasible. Alternative 3 is the easiest physical cleanup to
implement, requiring only replacement of sod. Alternatives 4, 5, 6 and the Preferred Alternative require
the extensive removal and replacement of soil as well as sod.
The excavation, soil replacement, and sodding activities performed under Alternatives 3
through 6 and the Preferred Alternative are common practices and do not limit the implementability of
these alternatives. Access to private properties would be required for Alternatives 3 through 6 and the
Preferred Alternative. Off-site disposal facilities are available for Alternatives 3, 5, 6 and the Preferred
Alternative. The availability of disposal services on the Asarco smelter facility under Alternative 4,
however, will not be determined until the cleanup action for the smelter is selected (see Section 7.5).
Each alternative involves the use of community protection measures to varying degrees. The
development, implementation, and enforcement of these measures would require extensive
coordination with other agencies and private parties. Under Alternatives 2 and 3, community-wide
acceptance of and compliance with community protection measures may be difficult to maintain over a
long period of time. Fewer community protection measures would be required as part of either the
Preferred Alternative or Alternatives 4, 5, and 6 due to the removal of the majority of contaminated soil.
8.7 Cost
The total cost of the alternatives is summarized in Table 17. These costs are estimated for the
purpose of comparison and are considered to be accurate within -30 to +50 percent. The estimates
are based on the estimated areas exceeding action levels (273 acres shown in Figure 5). The
alternatives, except for 4a, assume final disposal of contaminated soil at a facility outside of the
residential area. Alternative 4a assumes disposal of soil on the smelter site.
The incremental cost associated with the alternatives involving soil removal compared to the
alternatives that do not remove soil is reasonable and proportionate to the increased effectiveness
over the long-term of the soil removal alternatives (also see the discussion of cost-effectiveness in
Section 10.3 below). Moreover, the estimated cost of the Preferred Alternative is well within the range
of estimated costs for Alternatives 4 through 6.
Modifying Criteria
8.8 State Acceptance
Ecology agrees that the long-term effectiveness of an alternative corresponds directly to the
extent to which contaminated soil is removed.' Ecology believes that the engineering action levels
selected represent a best balance of the factors related to this site. Ecology further believes that the
residual risks can be adequately addressed through CPMs. Ecology emphasizes that this decision on
engineering action levels is specific for the factors related to this site only. Accordingly, Ecology
concurs with the EPA preferred alternative and the remedy selected in this ROD.
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8.9 Community Acceptance
Community acceptance is an important consideration in the selection of a cleanup remedy for
the Ruston/North Tacoma Study Area. Generally, community concerns about the site have centered
around the significance of the potential health threat from the contaminated soils, the stigma
associated with living at a Superfund site, and the resulting economic impacts. Some citizens have
questioned whether the risk warrants a cleanup, while others have stated that they would prefer EPA
to err on the side of protectiveness. Because the estimated risks do warrant cleanup, and acceptance
of cleanup measures by the community is important to successful implementation of the remedy, EPA
implemented a significant community involvement plan throughout the RI/FS activities.
The goal of the community involvement plan was to provide opportunities for the community to
actively participate in developing the remedy. The community became involved in a variety of ways
including: the Ruston/North Tacoma Coordinating Forum and Community Workgroup; regular
community meetings (open houses, workshops, public meetings); and by commenting during two 60-
day public comment periods held during the RI/FS and Proposed Plan processes. (A more detailed
description of community involvement activities can be found in Section 3).
During the first of two public comment periods (February - April 1992) EPA requested public
comments on the six alternatives evaluated in the FS. EPA used the comments received to develop
the Preferred Alternative which was outlined in the Proposed Plan. Public comments were submitted
on a variety of subjects including: health concerns; property values; soil sampling and disposal;
community protection measures; cleanup levels; and the length of time to complete a cleanup. A
summary of the comments received during the first comment period and EPA's responses is included
in section (F) of the Proposed Plan.
The Preferred Alternative (described in the Proposed Plan) consisted of elements from five of
the six alternatives described and evaluated in the FS. For the Preferred Alternative, EPA selected
elements that were protective of human health and the environment, and those that commenters
recommended. The Proposed Plan including the Preferred Alternative was the subject of the second
public comment period (August - October 1992).
Specific comments on the Proposed Plan included comments pertaining .to: homeowner
involvement in the cleanup; expanding the cleanup area; the depth of soil excavation; paving of dirt
roads; the overall protectiveness of the plan; and support of the plan. See the Responsiveness
Summary included as Appendix A of this ROD for a detailed summary of public comments from both
comment periods, and EPA's responses.
In general some community members still do not believe that cleanup of arsenic and lead
contaminated soils in the Study Area is necessary. Other commenters, however, felt that if EPA must
require a cleanup, the Preferred Alternative addressed many of their concerns: In addition, some
community members commented that a cleanup was necessary and should be implemented. Some
felt that soil should be cleaned-up to reduce the potential health risks, while others thought a cleanup
would eliminate the 'stigma' that they feel EPA's Superfund activities have created in the community.
One common theme contained in most of the comments was the need for input from the
homeowners. Commenters felt that a homeowner should have a say in what happens on their
property and not be subject to, or pay for, actions they didn't want.
Although there is not a consensus within the community on whether cleanup actions should
be taken, by involving the public in developing the cleanup plan, and by addressing many community
concerns in the Preferred Alternative and the Selected Remedy, a remedy has been selected that will
be acceptable to many members of the community.
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EPA will continue to implement community involvement activities throughout the cleanup to
ensure that homeowners and other interested citizens continue to be involved. These efforts will
include working individually with homeowners before, during and after cleanup to make sure the work
is done properly and to their satisfaction.
9.0 THE SELECTED REMEDY
EPA has selected the Preferred Alternative, as modified by public comments, as the remedy
for contaminated soil in the Ruston/North Tacoma Study Area. This remedy addresses soil irr
residential, commercial, and public areas, vacant lots, parking strips, landscaped areas, garden areas,
unpaved driveways, and roadway shoulders. In addition, this remedy addresses slag used in
driveways and other areas where slag use could lead to potential human exposure.
The remedy employs both engineering and community protection measures to reduce
exposure of current and future residents to contaminated soil and dust, and to reduce the potential
transport of soil contaminants inside homes or buildings where exposures may occur. Following are
the individual components of EPA's Selected Remedy.
9.1 . Sampling
The following approach will be used to determine the individual properties or areas at which a
cleanup will take place (i.e., those properties or areas, including significant areas within individual
properties, that exceed action levels):
(a) Surface and depth samples will be taken at all properties within the shaded area in
Figure 5 (i.e., the area where properties are most likely to exceed action levels). Depth samples will
be taken in order to determine the extent of contamination and the level of excavation required. In
addition, all schools, parks, and playgrounds within the Study Area will be inventoried and sampled.
(b) Additional samples will be taken in areas outside the shaded area, including the three
properties immediately outside the Study Area, where concentrations in excess of action levels were
detected.
(c) Samples will also be taken at properties outside of the shaded area but within the
Study Area as needed to supplement the Rl sampling results or at the request of property owners. If
a sampled property or area is identified as exceeding action levels, sampling will also be conducted at
contiguous properties.
(d) EPA will provide sample results to homeowners in the Study Area and indicate
whether a cleanup is or is not necessary.
(e) EPA will evaluate the need for further sampling (and appropriate cleanup activities)
outside the Study Area separate from the final cleanup action for the Study Area (see Section 4.1 of
this ROD for additional information).
(f) The current data base of sampling results will be expanded to store the results for all
of the properties that are sampled (see Section 9.10 below).
9.2 Small Quantity Soil Disposal Program
A soil collection and disposal program will be conducted for owners of properties requiring
cleanup (i.e., properties where sample results exceed action levels) that generate small quantities of
soil prior to the final cleanup of their property (see Section 9.10 (b) below on post-cleanup soil
collection service).
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9.3 Excavation of Contaminated Soil, Sod, and Slag
At properties or areas where soil exceeds action levels (230 ppm arsenic and 500 ppm
lead)8, soil and sod will be excavated. Slag driveways within the Study Area (as well as other uses of
slag where small panicles could be ingested) will be excavated and replaced with gravel. Large
pieces of ornamental slag, e.g., slag used in retaining walls or as a landscaping feature, will not be
removed.
(a) Removal activities generally will address sod areas (residential, public, and
commercial), landscaped areas, garden areas, unpaved driveways, and roadway shoulders. Removal
activities, in general, will not address soil within residential areas that is covered by an existing
structure or hard surface, e.g., concrete pads, patios, sidewalks, driveways, crawl spaces, wooden
decks, and dirt basements and garages. When these conditions are encountered within a residential
yard, flexibility will be employed in making cleanup determinations by considering the following factors:
(1) the potential for exposure; (2) the feasibility of conducting the cleanup; and (3) contaminant
concentrations in other parts of the yard (i.e., as an indication of possible concentrations in covered
areas).
(b) The depth of excavation at individual properties will depend on the depth of
contamination shown by sampling results, but will not in general exceed a maximum depth of 18
inches. Flexibility will be used in making cleanup determinations in those areas where contamination
may extend just slightly below 18 inches.
(c) Samples will be taken after excavation to confirm that contaminated soil from
properties or areas that exceed action levels has been removed.
(d) Excavated soil and sod will be replaced with 'clean* soil and sod, i.e., soil with
concentrations of arsenic and lead that do not exceed concentrations commonly found in local urban
areas - 20 ppm arsenic and 250 ppm lead. Even lower values for the replacement soils, especially for
lead, are likely achievable, e.g., lead less than 100 ppm. Vegetation will be replaced. Slag will be
replaced with gravel.
(e) It may be necessary to establish a temporary staging area or transfer facility for
excavated soil within or near the Study Area, potentially including on the Asarco smelter site. The
transfer of materials may be required because many streets throughout the Study Area cannot be
easily accessed by the larger vehicles that will be used to transport removed soils to the disposal
location. The staging area or transfer station is not meant, however, to serve as a long term storage
facility.
9.4 Properties or Areas Where Soil Above Action Levels Remains
If areas above action levels remain below 18 inches, the replacement soil will serve as a cap
or barrier to the remaining contaminated soil. Vegetation will be replaced.
8 Based on comments received during the Proposed Plan public comment period, there is some
misunderstanding regarding the cleanup of properties contaminated solely by lead. It is possible that
some exceedances of 500 ppm soil lead may occur in the Study Area unrelated to releases from the
Asarco smelter. Under this remedial action, EPA will take or compel remedial actions at the site that
address current contamination from smelter operations and releases, but not similar contamination
resulting from other sources, such as lead-based paints or automotive emissions, that are widespread.
The Superfund law limits the extent to which EPA can address releases from these other sources (see
CERCLA § 101(22) and § 104(a)(3), 42 U.S.C. §§ 9601(22) and 9604(a)(3)). Some property-specific
determinations may be required to decide on the inclusion or exclusion of such areas as part of site
remediation.
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(a) A 'marker,' e.g., a geotextile fabric or geocomposite material, will be used to clearly
identify the base of the cap for future intrusions.
(b) Community protection measures, described below in Section 9.10, will apply to the
capped areas.
9.5 Dirt Alleys and Parking Areas
Dirt alleys and parking areas with soil that exceeds action levels will either be capped with
asphalt to provide an impermeable barrier to contaminants, or the contaminated soil will be removed
and replaced with clean gravel. A determination regarding the appropriate option will be made based
on consideration of the sampling results and the extent of contamination, the relative cost
effectiveness of the options given the area to be remediated, and consultations with the local
municipalities.
9.6 Fencing
Soil in areas which are too steeply sloped to be excavated will be fenced and planted with low
lying shrubs (see Figure 6). A geotextile material will be applied to the soil to provide erosion
protection, as well as a means for supporting vegetative development.
9.7 Cleanup Timeframe, Schedule and Prioritization
The cleanup of properties will generally proceed within an area at a time, beginning with the
most highly contaminated areas. The Study Area will be divided into manageable zones. To the
extent possible, within an area or zone, priority may be given to schools, parks, playgrounds,
daycares, homes with children, or other areas where children tend to gather." EPA believes that this is
not only the most efficient method for cleaning up properties, but that this strategy will be the least
disruptive to the community overall.
Attempts will be made to shorten the estimated 7 year cleanup timeframe as much as possible
by using the maximum amount of trucks, crews, etc., that are available and that the community is
willing to tolerate. Community input will continue to be sought as the cleanup progresses and zones
are established and individual lots scheduled for cleanup actions (see Section 9.16 below).
9.8 Information for Deed Notice
If requested by an owner of property, a factual description of the sampling results and/or the
cleanup that has been completed at that property will be provided. Owners may want to use this
information for the purpose of a deed notice to show that the property did not require cleanup actions,
or that cleanup actions were completed on the property.
9.9 Safety Measures
During implementation of the cleanup, safety measures will include, at a minimum, air
monitoring, the use of dust suppression techniques during excavation activities, covering of any
stockpiled materials, lining and covering truck beds when transporting contaminated materials,
removing soils from truck wheels before trucks travel on public roads, and the establishment of a
transportation plan to establish local truck routes to minimize disruption to the community.
9.10 Community Protection Measures
The CPMs program for the Study Area included in this ROD addresses: (1) areas where
complete removal of soils above the action levels is not practicable, e.g., areas where-contamination
above the action levels is to be left at depths greater than 18 inches or may be detected in the future
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under roadways, sidewalks or buildings; as well as (2) areas where soil arsenic levels exceed
concentrations normally found in urban areas, but are below the action levels and therefore would not
require cleanup. The appropriate CPMs for soils in the second category include educational
measures on how to minimize contact with contaminated soil, measures to take if contact does occur,
how to dispose of soils in an environmentally safe manner, and the components listed under (d), (e),
and (f) in this section below. The appropriate CPMs for soils in the first category are discussed further
below.
EPA believes that the measures outlined in this Section, at a minimum, are the most effective
way to implement the CPMs program. Specific details for the program will be finalized during the
design phase of the cleanup.
A full time person from the TPCHD will be funded to serve as the CPMs program coordinator.
The coordinator will be responsible for developing and carrying out the program elements described
below, and for coordinating the development, implementation, and evaluation of the CPMs program
with a workgroup9 and the Community Relations Program coordinator (described below in Section
9.16). The CPMs program will include, at a minimum, the following elements:
(a) Measures to control soil disturbances.
Guidelines and safety procedures will be developed for conducting excavations so that
contact with remaining contaminated soil is minimized, and that such soil is appropriately disposed.
The guidelines will address the following areas: (1) significant development projects; (2) soil
disturbance activities conducted by homeowners or citizens; and (3) utilities maintenance projects.
The guidelines for conducting significant development projects will be dispensed with permits
issued in Ruston and Tacoma.
The information for homeowners will address any special considerations identified, e.g.,
children, parents, and eating garden vegetables. Day cares will be identified as a specific audience
for receiving educational material. In addition, educational material will be developed for distribution in
the schools.
The CPMs program coordinator will work directly with Ruston and Tacoma to identify specific
departments conducting utility maintenance activities. Educational materials, including appropriate
distribution methods, will be developed to address the needs of the identified departments.
(b) Soil testing, collection, and disposal program.
A soil testing, collection, and disposal program will be developed to apply when soil above the
action levels is excavated from beneath a cap or other area where contamination remains, including
from existing ERA sites (see Section 9.12 below). The program will be available for contaminated soil
that is excavated as a result of small scale homeowner activities, development projects, and City or
9 As part of the proposed conditional exemption for arsenic contaminated soils in the Ruston/
North Tacoma Study Area, Ecology will require an ongoing education program to inform residents
about appropriate measures to minimize residual risk from contaminated soils, and the proper
management of these soils. To meet the requirements for coordinating the education program with
local and state government, staff conducting the program will work with a workgroup to set goals for
the education program and provide input from the community on education measures. The
workgroup will include representatives from the Town of Ruston, the City of Tacoma, TPCHD, EPA and
Ecology, as well as residents of the Study Area, members of the business community, parents,
students, school personnel, and other interested citizens. The workgroup will provide" guidance in the
development and implementation of the education program.
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Town maintenance projects. Transportation of excavated material to the disposal facility will be
provided. A component of this program will address the development and distribution of information
on the availability and use of this program.
(c) Measures to maintain the integrity of caps.
A maintenance and monitoring program will be established to ensure the continued integrity of
soil, sod and asphalt caps, including visual inspections of capped areas. Maintenance activities will
include repair of damages to, or failures of, caps that are caused by improper placement, e.g.,
insufficient drainage measures.
Homeowners will generally be responsible for maintaining and repairing established caps in
individual yards as part of the normal upkeep of private property. The City and Town will be
responsible for general cap maintenance and repair activities on public access areas and roadways,
but not for damage as a result of remediation activities or as a result of a failure of the remedy.
(d). Development of a property specific data base:
Information regarding sample results and cleanup activities at individual properties will be
consolidated into a data base. The data base will be easily accessed, frequently updated, and
centrally located and maintained. The data base will be available to interested individuals (e.g.,
property owners) in Ruston and Tacoma. Efforts will be made to determine the best ways to inform
people about the existence of the data base, as well as additional parties that need to be made aware
of its existence, e.g., real estate personnel.
(e) Notification to future property owners.
The data base will provide information to current and future property owners regarding (1)
sample results, (2) completed cleanup efforts, and (3) cap maintenance responsibilities for properties
or areas where contamination remains above the action levels. The real estate and lending
communities will be informed about the data base to ensure that information necessary for property
transfers is readily available.
(0 Evaluations of the effectiveness of the CPMs program.
A yearly progress report will be prepared regarding activities and educational measures
conducted under the CPMs program. The workgroup, identified above, together with an independent
entity identified by the workgroup, will be responsible for reviewing the report, evaluating the
adequacy of the CPMs program, and suggesting any necessary changes.
9.11 Funding
As part of the remedy, a funding mechanism will be established under EPA, state or local
direction or oversight to provide resources to implement the selected remedy including ongoing
educational measures and the community protection measures program.
9.12 Expedited Response Action Properties
In 1990, 1991, and 1992 under an Administrative Order on Consent with EPA, Asarco
conducted cleanup actions at 10 publicly accessible areas (and portions of an 11th area) where soil
exceeded 250 ppm arsenic. The top 3 inches of soil was removed and replaced with a 9 to 12 inch
soil cap. Access agreements between Asarco and the property owners were established that
included provisions for the care, maintenance and monitoring of the soil and vegetation caps. These
agreements were designed to be effective until the completion of the Ruston/North Tacoma RI/FS and
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the issuance of this ROD. As part of the RI/FS, EPA evaluated the ERA sites to determine whether the
ERA was an effective permanent remedy.
The Selected Remedy is similar to the ERA activities in that they both involve the removal and
replacement of contaminated soil, and provisions for the care, maintenance and monitoring of soil
caps. Under the Selected Remedy, the ERA properties will be sampled to a depth of approximately
18 inches from the surface of the cap. If contaminated soil is found, the ERA property will be included
in the community protection measures program (see Section 9.10) outlined in this ROD. Given that
this effort provides for the. continued care, maintenance and monitoring of ERA site soil caps, further
remediation of ERA sites is not necessary.
The portions of Site 8 of the ERA properties that have not yet been remediated will be cleaned
up in accordance with the Selected Remedy under this ROD.
9.13 Disposal
Current state regulations require disposal of removed soil with arsenic concentrations above
100 ppm at a hazardous waste facility (Dangerous Waste Regulations, 173-303-141 WAO). The
nearest such facility is located in Arlington, Oregon. Asarco has submitted a petition to Ecology
requesting an exemption from the requirements of these regulations. Ecology has evaluated the
petition and has proposed to conditionally exempt both soil with arsenic concentrations less than 230
ppm, and soils with arsenic concentration greater than 230 ppm from the disposal criteria required in
the regulation.
Where soils with arsenic levels at or below the 230 ppm action level are excavated,
educational measures will be provided on how to minimize contact with and dispose of these soils in
an environmentally safe manner. For soils with arsenic concentrations over the 230 ppm action level,
specific disposal facility criteria have been proposed. The proposed conditions of the exemption are
described in Table 16. These conditions, when finalized, will be requirements for the Selected
Remedy.
Based on the current information regarding disposal as described in the paragraph above,
EPA has selected disposal at an appropriate off-site facility for the Selected Remedy. If the dangerous
waste exemption is approved, however, other possible disposal locations for Study Area soil may
become available in the future. For example, there are other non-hazardous waste landfills in the state
which might meet the exemption requirements. In addition, before EPA selects a cleanup remedy for
contaminated soil and ground water at the Asarco smelter site, EPA expects to consider a range of
cleanup alternatives that may include consolidation of contaminated soil on the. smelter site, treatment
of contaminated soil and ground water, capping of contaminated soil, and excavation and off-site
disposal of contaminated soil. It is possible that if EPA decides to select on-site disposal, capacity
may be available for Study Area soil. EPA notes, however, that its decision on the cleanup of the
Study Area is separate and apart from its decision on the cleanup of the smelter site. The selection of
a cleanup remedy for the Asarco smelter site will be subject to further public review and comment.
9.14 Homeowner Access and Approval
Cleanup activities will be coordinated with homeowners to define the extent of work to be
performed on individual properties. The following activities will take place prior to any soil removal
activities on an individual property:
(a) Work with property owners to obtain access for sampling and conducting the remedy.
(b) Conduct site survey, photograph or videotape properties, and prepare detailed plan
for each property. Verify stability of structures on the property, including foundations,-with respect to
anticipated depth of excavation (also see Section 9.17 below).
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(c) Schedule the work with the homeowner.
9.15 Landscaping
The actual vegetation removal and replacement plan will be determined on a property-by-
property basis to accommodate both the project needs and property owners to the extent that is
reasonably possible. Reasonable attempts, which do not hinder the progress of the remediation and
are not excessively costly, will be made to accommodate owners who desire to retain original
landscaping.
9.16 Community Relations During Cleanup
A community relations program, including a full time coordinator, will be established to provide
coordination and communication between cleanup personnel, residents, and property owners. The
community relations program coordinator will work together with the coordinator and workgroup
identified under the community protection measures program above (Section 9.10) to address the
needs of the community including residents, businesses and schools. This program will include the
following elements at a minimum:
(a) Establishment of a local information center within the community where information
regarding cleanup activities and schedules could be obtained.
(b) Coordination and communication of cleanup schedules with property owners,
including discussions with property owners and day care operators regarding the appearance of the
community during cleanup activities, and any recommended safeguards or precautions.
(c) Notification to residences, businesses, and schools prior to the start of remediation
efforts.
(d) Preparation and distribution of regular project updates to businesses, residents, and
schools, and the identification of additional ways of keeping people informed about cleanup activities
and progress.
(e) Regularly scheduled community meetings to discuss cleanup schedules and
processes, and to address questions and concerns regarding cleanup activities.
9.17 Incidental Damage During Remediation
All possible precautions will be taken during remediation to avoid damage to property. It is
possible, however, that the excavation of soil from properties, and the use of heavy equipment for
remediation and transportation activities, may result in damage to some underground utilities, sprinkler
systems, fences, foundations, yard lighting, roads, sidewalks, etc. Efforts will be made to anticipate
and minimize these possible problems by working with the homeowners, municipalities, and utilities to
prepare sketches of each property to identify all known underground items.
In addition, all properties including roads and sidewalks will be surveyed and inspected prior
to remediation activities to establish existing conditions. Items damaged as a result of remediation
activities will be repaired or replaced where feasible, As part of the replacement of clean soil on
individual properties, efforts will be made to ensure adequacy of drainage and erosion control.
9.18 Cost of the Selected Remedy
EPA estimates a range of $60 to $80 million total present worth costs to conduct the Selected
Remedy. The lower cost reflects the disposal of contaminated soil at-a non-hazardous waste disposal
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facility (see Section 9.13 above) and the higher cost indicates disposal at an out-of-state hazardous
waste facility. See Section 8.7 for more information on cost estimates and comparisons.
10.0 STATUTORY DETERMINATIONS
10.1 Protection of Human Health and the Environment
The selected remedy will eliminate, reduce, or control exposure to contaminants at properties
or areas that exceed action levels for arsenic and lead as a result of emissions from the smelter.
Risks from exposure to soil that exceeds the action levels will be eliminated by removing contaminated
soil and disposing it elsewhere. Where soil removal is impracticable, e.g., where areas above action
levels extend below 18 inches in depth, the risk will be controlled by placing a cap of clean soil and
sod above the contaminated area to act as a barrier to direct contact exposure.
The goal of CPMs is to ensure that the remedy remains protective over the long-term. The
objectives of CPMs include: monitoring the condition of the caps; informing homeowners - current and
future - that residual contaminated areas exist on certain properties (or may exist in certain areas, e.g.,
below structures or roadways); and educating residents on minimizing exposure to contaminated
areas, managing and disposing of soil if contaminated areas are excavated, and reducing exposure to
concentrations that are below action levels but above levels that are commonly found in urban areas.
Short-term risks to the community during implementation of the cleanup action will be
minimized through dust control and other protective measures.
10.2 Compliance with Applicable or Relevant and Appropriate Requirements
The selected remedy will attain ARARs under federal and state law (see Table 16).
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 under NCP section 300.430(f)(1)(D). In determining this
•proportionality,1 EPA compared the differences in cost and effectiveness between the two primary
cleanup approaches under consideration for the Study Area: (1) removing from the Study Area as
much soil that exceeds the action levels as feasible, replacing the removed soil with clean soil, and
disposing the contaminated soil elsewhere (the Selected Remedy); versus (2) leaving the
contaminated soil or dirt in place and covering it with sod or asphalt (Alternative 3 in the Feasibility
Study). The difference in cost is justified based on the difference in effectiveness over the long-term
between the two approaches.
The significant advantage to the more costly soil removal and replacement approach is that it
permanently removes the majority of soil exceeding action levels, and therefore significantly reduces
the need for community protection measures on many individual properties. The owner and residents
of a property where soil contamination above action levels has been removed and replaced with clean
soil will be able to enjoy the use of the property without undue restriction. Where it is not practicable
to remove all contaminated soil, e.g., where soil above the action levels remains below 18 inches from
the surface, the cleanup approach will rely on a cover of sod and 18 inches of clean soil to prevent
exposure to the contamination. Soil caps will be necessary only at a limited number of properties.
The primary disadvantage to placing only a thin sod cover over existing contaminated soil is
that supplemental measures will always be required to ensure that the sod cover continues to provide
protection against the contamination. Sod covers can fail as a result of several types of disturbing
activities, thus exposing residents to contaminated soil. Such disturbing activities, which reasonably
could occur at many properties, include changes in structures on a property (e.g., adding-a deck,-
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tearing down a toolshed), loss of vegetative cover from imposition of lawn watering restrictions, or
establishing or relocating a garden or children's play area
The soil cap that would be used under the Selected Remedy where contaminated soil remains
would not be as easily penetrated or degraded by human activities or dry conditions because of its
thickness. Failures of sod covers are much more likely than failures of a sod-covered 18 inch soil cap,
i.e., the protectiveness and long-term effectiveness of a cap increases as the thickness of the cap
increases.10
In comparing the cost-effectiveness of the two cleanup approaches, EPA reevaluated the
community protection measures components under both Alternative 3, as described in the FS, and the
Preferred Alternative, as described in the Proposed Plan. More comprehensive long-term monitoring,
maintenance, and repair measures for the sod covers as well as an enhanced soil collection service,
especially for Alternative 3, would be necessary for an effective long-term cleanup. Such measures
would make Alternative 3 nearly as effective as the Selected Remedy in preventing or reducing
exposure to contaminated soil. Alternative 3 would not be as effective over the long-term as the
Selected Remedy because of the impossibility of ensuring complete compliance with the maintenance,
monitoring, and repair requirements at over 500 properties estimated by EPA to have soil exeeding
the action levels.
In order to prevent failure of sod covers, they would have to be monitored on a regular basis
and repaired when necessary. Also, an extensive program would have to be developed to ensure that
'all* current and future homeowners and residents are fully aware of the need to maintain the cover in
order to avoid exposure to contaminated soil. Further, the soil collection, testing, and disposal
program would have to be substantially more intrusive and encompassing than under the Selected
Remedy. This measure would be required in order to accommodate the contaminated soil that would
not be removed during EPA's cleanup, but which may be excavated in the future as the result of some
of the activities described above.
Because additional measures would need to be added to Alternative 3 to increase its
protectiveness over the long-term. EPA has re-estimated the cost of Alternative 3 with such measures.
The estimated cost of Alternative 3 in the FS was $24 million, which has been increased for a revised
Alternative 3 to $36 million (non hazardous disposal). See Bechtel Memorandum dated May 1993
entitled "Revised Cost Estimates for the Selected Remedy and Alternative 3 at Ruston/North Tacoma
Washington. Based on this reanalysis of the cost of long-term measures, which are necessary to a
much less extent for the Selected Remedy, EPA's estimate of $60 million for the Preferred Alternative
(nonhazardous disposal) has been revised to $62 million for the Selected Remedy.11
10 It should be noted that it does not appear practicable to use soil and sod covers without
removing soil - i.e., adding up to 18 inches of soil without removing an equivalent amount of soil first
would seriously impact grading and drainage patterns.
11 EPA has not reevaluated. the cost of every other alternative in the FS because determining
whether the Selected Remedy was cost-effective required only a comparison of the two distinct
strategies to the cleanup - removing contaminated soil versus leaving contaminated soil in place with
a sod cover.
Alternatives 4 and 5 as described in the FS varied the disposal locations for the contaminated
soil. The estimated cost of the Selected Remedy is based on disposal of removed soil in either the
hazardous or nonhazardous facilities in Arlington, Oregon. Although this ROD selects appropriate off-
site disposal, it does not preclude other disposal options that may become available in the future,
including disposal on the smelter site (e.g., removed soil could be used as a subbase for capping or
disposed in an on-site disposal facility).
37
-------
Despite the significantly increased estimate of cost for Alternative 3, the continued
effectiveness of such programs for hundreds of properties over many years would be problematic
because the continued enforcement, awareness, and acceptance of such controls cannot be
guaranteed. Moreover, the continual intrusiveness of such programs into an owner's use of his/her
property may be substantial.
There is an advantage in the effectiveness over the long-term of a cleanup that removes most
of the contaminated soil, as opposed to a cleanup that uses sod covers to contain contaminated soil.
This advantage is well worth the incremental difference in cost - $62 versus $36 million - between the
two approaches. Accordingly, the cost of the Selected Remedy is proportional to its effectiveness and
is, therefore, cost-effective under CERCLA and the NCR.
10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Maximum Extent Practicable
The selected remedy is permanent to the maximum extent practicable because it requires
removal from the Study Area of most of the soil contaminated above action levels. Removal of soil
from properties or areas that exceed action levels significantly reduces the risk to residents of the
Study Area Soil removal to the maximum extent practicable* is defined for purposes of the Study
Area as properties or areas that exceed action levels down to 18 inches below the surface. This
maximum extent practicable determination is based on the infeasibility of excavating and disposing of
soil from below 18 inches in depth together with the effectiveness of soil caps to control exposure to
contaminated soil below 18 inches.
The selected remedy represents the best balance of tradeoffs among the alternatives
considered in the FS and Proposed Plan. The primary criterion relied upon in making this
determination is 'long-term effectiveness and permanence,' which is analyzed'above as part of the
•protectiveness' and 'cost-effectiveness' determinations. Also of significance in making this maximum
extent practicable determination are comments received from the community. Among the residents in
favor of a cleanup, most favor the cleanup approach that physically removes contaminated soil from
the Ruston/North Tacoma Study Area.
As explained on pages 2-60 through 2-69 of the FS, and in the introduction to Section 7.0 of
this ROD, active treatment measures are not practicable to address the large volumes of contaminated
soil within the Study Area.
10.5 Preference for Treatment as a Principal Element
As explained in Section 10.4 above, the selected remedy will not satisfy the preference for
treatment.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
During the public comment period on the Proposed Plan, EPA received comments from
Asarco regarding the asphalt paving of dirt alleys and parking areas where soil exceeds the action
levels. Asarco commented that compared with asphalt capping, removal of contaminated soils from
alleys and parking areas followed by replacement with clean gravel would be a superior alternative.
Since any options associated with disposal of Study Area soils on the smelter property can
only be implemented if determined to be appropriate under the smelter cleanup, which is not
expected to begin for several years, this cost-effectiveness analysis for the Study Area cleanup does
not consider the cost of the smelter options. If such options are approved and implemented, however,
EPA expects that the cost of the Selected Remedy may be reduced as disposal costs would be lower.
38
-------
Asarco also suggested that the removal and gravel replacement option would be more cost effective
than asphalt capping, and would also provide a more permanent solution.
EPA has reevaluated the Proposed Plan requirement for asphalt paving of dirt alleys and
parking areas exceeding the action levels. The two approaches are similar in terms of their overall
protectiveness. The primary difference between the two approaches is the need for long term
maintenance of asphalt caps that are underlain by contaminated soils. The frequency of intrusions to
the asphalt caps, however, would be less than those in residential lawn areas.
Accordingly, Section 9.5 of this ROD allows for dirt alleys and dirt parking areas that exceed
action levels to be either capped with asphalt to provide an impermeable barrier to contaminants, or
for the contaminated soil to be removed and replaced with clean gravel. A determination regarding
the appropriate option will be made based on consideration of the following factors: (1) the sampling
results and the extent (depth) of contamination; (2) the relative cost effectiveness of the options given
the area (size) to be remediated; and (3) consultations with the local municipalities.
39
-------
53rd
52nd
33
51st
50th
49lh
Ruby
48th
Seav itt
47U
\\
FORMER
STACK
ASARCO
17
Ruston Town Limits
ERA Site Number
FKET
500
1000
Expedited Response
Action Sites
FIGURE 2
-------
FIGURES
-------
COMMENCEMENT
R us I o n / N o r I h T a c o m a
Study Area
nnr
too mo
FIGURE I
-------
Total Arsenic
Distribution
FIR & R I Data
S u r f a ce Soil
MtNl
It; to trfeoic •|/k|
I U 41
47 In 210
t]l to 419
401 I > 191
Cr«'il«i Tim I tO
8 I SlBf I I i| Lot il Uo t
r I I Siaf I I i( Ut I I I oo I
900 UOO
FIGURE 3
-------
irmiL
— —
nnnnnr
hnnnnr
II Slip lii| Liotieat
f II Sl*p I i i| Uci Him
110 !!«•
FIGURE 4
-------
Figure 5:
Study Area and Estimated Portions Exceeding Action Levels
Study Area
Ruston Town Limits
Estimated Portions
Exceeding
Action Levels
M\ N.38th SL
300 0 300 600
.1 I II IL
Based on the existing sampling results, EPA has estimated that the areas which are shaded on the map may require cleanup
because they most likely exceed EPA' s action levels. There could, however be properties within the shaded area that have soils
with contamination below the action levels, anal or properties outside the estimated area that have contamination in excess of
the action levels.
-------
FORMER
STACK
Steeply Sloped Area to
be. End ose d by Fenc e
FEET
0 500 1000
Proposed Fenced Area
FIGURE 6
-------
TABLES
-------
Table 1
RUSTON/NORTH TACOMA STUDY AREA
INFORMATION REPOSITORIES
Study Area
In Tacoma:
In Ruston:
In Seattle:
*
In Olympia:
Address
McCormick Regional Branch Library
3722 North 26th
(206) 591-5640
Tacoma Public Library, Main Branch *
1 1 02 Tacoma Avenue, NW Room
(206) 591-5622
City of Tacoma
Environmental Commission
747 Market Street, Suite 900
(206) 591-5310
Tacoma Pierce County Health Dept.
. 3633 Pacific Avenue
(206) 591-6553
Pacific Lutheran Library.
121st & South Park Avenue
(206) 535-7500
Citizens for a Healthy Bay
771 Broadway
(206) 383-2429
Ruston Town Hall
51 17 North Winnifred
(206) 759-3544
U.S. Environmental Protection Agency * .
1200 Sixth Avenue
7th Floor, Records Center
(206) 553-4494
Washington Department of Ecology
4415 Woodview Drive, S.E.
(206) 438-3017
* The Administrative Record for the Ruston/North Tacoma Study Area is available at these two
locations.
-------
Table 2
UST AND DESCRIPTION OF FACT SHEETS AND BROCHURES
REGARDING THE RUSTON/NORTH TACOMA STUDY AREA
Date
4/27/89
7/14/89
9/89
11/1/89
2/12/90
2/90
5/2/90
6/8/90
8/90
11/5/90
2/13/91
5/6/91
8/6/91
10/91
Topfc<8)
Described cleanup work underway at ERA sites and announced EPA's intent to
conduct an overall investigation of the Study Area The fact sheet also included
information about the availability of a Technical Assistance Grant for local
community groups.
Disclosed EPA's request that Asarco conduct an RI/FS, and invited the community
to join a community workgroup.
Provided update of all Superfund projects in Tacoma
Summarized the first community workgroup meeting, and provided opportunity for
property owners to request soil sampling.
Introduced EPA's Community Liaison, and provided an update of site activities and
progress of the Community Workgroup.
Provided update of all Superfund projects in Tacoma including a status report on
Ruston/North Tacoma.
Announced the final Rl workplan and EPA's plans to contact private property
owners for access for sampling. Contained frequently asked questions and EPA's
responses. Updated ERA activities and the Community Workgroup.
Announced the beginning of soil sampling and introduced EPA's new project
manager.
Provided update of all Superfund projects in Tacoma including a status report on
Ruston/North Tacoma
Summarized soil sampling results, provided TPCHD recommendations for reducing
exposure to soil contamination, and invited residents to a special Community
Workgroup meeting to discuss the sample results.
Provided update of all Superfund projects in Tacoma including the ERA sites, and
the status of the Ruston/North Tacoma Rl. Also included information on EPA's
Community Workgroup and community interviews which were underway.
Provided update of all Asarco Superfund projects including community interviews
and Community Workgroup for the Ruston/North Tacoma Study Area.
Provided update of all Superfund projects in Tacoma including the Ruston/North
Tacoma Rl, the Coordinating Forum, and Ecology's soil collection service for Study
Area residents.
Distributed brochure 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.
-------
Table 2
UST AND DESCRIPTION OF FACT SHEETS AND BROCHURES
REGARDING THE RUSTON/NORTH TACOMA STUDY AREA
Date
2/10/92
3/92
3/92
6/92
7/92
7/14/92
8/14/92
11/92
1/11/93
Toptc(s)
Announced 60-day public comment period on EPA's RI/FS and Risk Assessment
reports and two public workshops.
Under a cooperative agreement with EPA, TPCHD developed two brochures related
to handling and disposal of contaminated soil in both residential and commercial
settings. These brochures were developed by TPCHD with input from EPA,
Department of Ecology and the members of the Coordinating Forum. TPCHD
distributed the residential brochures via a bulk mailing to the Study Area The
commercial brochures were also mailed to a variety of interested groups and local
government departments including: labor unions, schools, local parks, utilities and
zoning departments, and business organizations. These brochures are also
available at the permit counters in Tacoma and Ruston.
Provided update of all Superfund projects in Tacoma including the status of the first
60-day public comment period for Ruston/North Tacoma
Distributed brochure for property owners, realtors, appraisers, and lending
professionals to provide additional information on EPA's policies on liability for
cleanup costs.
Summarized property transaction seminar held in June 1992.
Updated all Asarco Superfund projects including the Study Area Also contained a
summary of a property transactions seminar held by EPA.
Summarized EPA's Proposed Plan for cleanup. Provided information about the 60-
day public comment period and two public meetings during that period.
Updated all Superfund projects in Tacoma including a status report on EPA's
progress in responding to public comments and developing a Record of Decision.
An update of ERA activities was also included.
Updated all Asarco Superfund projects including the Study Area
-------
Table 3
COMBINED REMEDIAL INVESTIGATION AND FIELD INVESTIGATION REPORT DATA
FOR SURFACE AND SUBSURFACE SOIL SAMPLES FROM THE STUDY AREA
Range of metal concentrations in surface soils at 0 - 1* (In ppm):
Arsenic:
Antimony:
Copper:
Mercury:
Cadmium:
Lead:
Silver:
Rang» of metal concentrations collected
Arsenic:
Antimony:
Copper:
Mercury:
Cadmium:
Lead:
Silver:
7.0 to 3,000
0.0 to <4.3
92.7 to 12,800
0.57 to 23.0
<0.43 to 13.4
24.7 to 2,700
< 0.84 to 30.6
at 6 ~ TO* (In ppm}:
2.1 to 2.900
< 4.4 to 14.4
79.7 to 1,080
0.0 to 0.36
< 0.48 to 15.2
34.0 to 429
<0.48 to 2.9
Range of metal concentrations collected at 12 • 16* (In ppm):
Arsenic:
Antimony:
Copper:
Mercury:
Cadmium:
Lead:
Silver:
1.9 to 1,380
< 4.7 to 13.7
33.510 1,220
0.10104.3
<0.47 to 6.5
6.5 to 660
<0.47 to 3.8
-------
Table 4
SUMMARY OF ARSENIC EXPOSURE FACTORS
Exposure
Model
Ambient
Air Inhalation
Soil/Dust
Ingest ion
Pica
Soil/Oust Ingestion
Slag/Oust
Ingestion
slag
dust
slag
dust
Dermal Contact
Age Group
Adults
0-6 yrs
6-30 yrs
0-6 yrs
6-30 yrs
0-6 yrs
0-6 yrs
6-30 yrs
6-30 yrs
0-6 yrs
6-30 yrs.
6-30 yrs
Body
Weight
70 kg
15 kg
70 kg
15 kg
70 kg
15 kg
15 kg
70 kg
70 kg
IS kg
70 kg
70 kg
Contact Rate
ZOmVday
200 mg/day
100 mg/day
500 mg/day
100 mg/day
22.5 mg/da/
110 mg /day
11.25 log/day"
55 mg/day
3900 mgc
1900 mgc
5000 mg
Frequency
350 day/yr
350 day/yr
350 day/yr
350 day/yr
350 day/yr
350 day/yr
3SO day/yr
350 day/yr
350 day/yr
3SO day/yr
263 day/yr
87 day/yr
Duration
30 yrs
6 yrs
24 yrs
6 yrs
24 yrs
6 yrs
6 yrs
24 yrs
24 yrs
6 yrs
24 yrs
24 yrs
Bioavailablity*
0.30
0.80
0.80
0.80
0.80
0.40
0.40
0.40
0.40
0.0015
0.0015
0.0015
Arsenic
Concentration
30 ng/m3
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
10,000 mg/kg
100 mg/kg
10,000 mg/kg
100 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
a Bioavat lability factors are pathway specific according to theiBaseline Risk Assessment.
b The slag/dust model incorporates a contact rate. .allocation factor that accounts for time and behavioral differences for
indoor and outdoor exposures. The RME assumption is that 0.45 of the contact rate is associated with outdoor activities
(i.e. slag and soil) and 0.55 is associated with indoor dust. The RNE also assumes that 25X of the outdoor exposure is
associated with slag at 10,000 mg/kg in the Baseline Risk Assessment.
c The dermal contact rate incorporates the area of skin exposed (cm2) for winter and sunnier and a factor of 1.0 mg/cm2 for
adherence of soil particles to skin.
Definitions
mg/kg =
: kg = kilograms, irvVday = cubic meter per day, ng/m3 = nanograms per cubic meter, ing/day = milligrams per day,
milligram per kilogram or parts per million (ppm), RME = reasonable maximum exposure.
-------
Table 5
EXPOSURE FACTORS FOR THE GARDEN VEGETABLE EXPOSURE MODEL FOR ARSENIC
Vegetable
Class
Fruity .
Leafy
(loot
Potatoes
Legumes
Age Croup
0-6 yrs
6-30 yrs
0-6 yrs
6-30 yrs
0-6 yrs
6-30 yrs
0-6 yrs
6-30 yrs
0-6 yrs
6-30 yrs
Body
Weight
IS kg
70 kg
IS kg
70 kg
IS kg
70 kg
15 kg
70 kg
IS kg
70 kg
Contact
Rate*
3.2 g/day
8.8 g/day
0.3 g/day
1.4 g/day
1.5 g/day
2.5 g/day
8.7 g/day
23.5 g/day
22.3 g/day
44.9 g/day
Frequency"
0.39
0.39
0.11
0.11
0.19
0.19
0.11
0.11
0.62
0.62
Duration
6 yrs
24 yrs
6 yrs
24 yrs
6 yrs
24 yrs
6 yrs
24 yrs
6 yrs
24 yrs
Bioava it ability
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Plant
Uptake
Factor'
0.0014
0.0009
0.00066
O.OOOS
0.0003
0.02
0.02
0.02
0.02
0.02
0.0014
0.0009
0.00066
0.0005
0.0003
0.0014
0.0009
0.00066
0.0005
0.0003
0.0014
0.0009
0.00066
O.OOOS
0.0003
Soil Arsenic
Concentration
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RHE)
1600 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RHE)
1600 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
140 mg/kg
300 mg/kg
500 mg/kg
800 mg/kg (RME)
1600 mg/kg
\
a Dry weight basis. Source: USEPA Methodology for Assessing Health Risks Associated with Indirect Exposure to Combustor
Emissions, Interim Final, EPA/600/6-90/003, January 1990. See also Appendix G of the Baseline Risk Assessment.
b Diet fraction grown at home (see Appendix E of the Baseline Risk Assessment).
c Site specific factors (see Appendix E of the Baseline Risk Assessment).
Definitions: kg = kilograms, g/day = grams per day, mg/kg = milligram per kilogram or parts per million (ppm),
RME = reasonable maximum exposure.
-------
Table 6
SUMMARY OF AVERAGE DAILY DOSE
AT VARIOUS SOIL ARSENIC CONCENTRATIONS
Soil Arsenic
Concentration
20 ma/kg
(urban, background)
140 ag/kg
(50m per cent He)
300 mg/ kg
(75*percentile)
500 ng/kg
(90*percentile>
800 mg/kg
(RME)
1600 mg/kg
(99* percent! le)
Averaging
Time
30 yrs
70 yrs
30 yrs
70 yrs
30 yrs
70 yrs
30 yrs
70 yrs
30 yrs
70 yrs
30 yrs
70 yrs
Exposure Model
Pica
(mg/kg/day)
1.2 x 10"*
5.1 x 10*
8.4 x 10"
3.6 x 10"
1.8 x 10-1
7.7 x 10-"
3.0 x 10°
1.3 x 10*
4.8 x 10'a
2.1 x 10 3
9.6 X 10'1
4.1 x 10'3
Soil/Oust
(mg/kg/day)
5.8 x 10'6
2.5 x 10"'
4.1 x 10"
1.8 x 10"
8.8 x 10"
3.8 x 10"
1.5 x 103
6.3 x 10"
2.3 x 10"3
1.0 x 10'3
4.7 x 10"3
2.0 x 10"*
Veget
(ma/kg
3 classes*
2.7 x ID'6
1.2 x 10-*
1.9 x 10s
8.1 x 10"4
3.1 x 10'6
1.3 x 10*
4.3 x 10'6
1.9 x 10"'
6.1 x 10*
2.6 x 10"s
1.0 x 10"
4.4 x 10'"
able
/day)
5 classes*
1.8 x 10'5
7.7 x 10-'
1.3 x 10"
5.4 x 10"s
1.8 x 10"
7.6 x 10"s
2.2 x 10"
9.6 x 10*
2.8 x 10"
1.2 x 10"
3.8 x 10"
1.6 x 10"
Dermal
(flig/kg/day)
2.4 x 10*
1.0 x 10"*
1.7 x 10'6
7.1 x 10 '•
3.6 x 10*
1.5 x 10*
5.9 x 10*
2.5 x 10*
9.5 x 10*
4.1 x 10'8
1.9 x 10"
8.1 x 10*
a 3 Classes = fruity, leafy and root
b 5 Classes = fruity, leafy, root, potatoes and legumes
Definitions: mg/kg/day = milligram per killogram per day,
mg/kg = milligram per kilogram or parts per million (pen),
RNE = reasonable maximum exposure.
Table 7 .
AVERAGE DAILY DOSE FOR ARSENIC IN
THE SLAG/DUST AND AIR RME MODELS
Averaging
Time
30 yrs '
70 yrs
Exposure Model
Slag/Dust
(mg/kg/day)
1.7 x 10*
7.4 x 10"
Air
(mg/kg/day)
2.5 x 10"'
1.1 x 10-*
Definitions:
RME = reasonable maximum exposure,
mg/kg/day = milligram per killogram per day
-------
TableS
EXPOSURE PARAMETER AVERAGE VALUES FOR THE UBK MODEL
FOR 0 TO 6 YEAR OLD CHILDREN
Parameter
Outdoor air lead (ttg/m3)
Indoor air lead Ug/m3)
Time spent outdoors (hour/day)
Time weighted average (jig/m3)
Breathing volume (ra'/day)
Lead intake from breathing air (fig/day)
Percent respiratory deposition/absorption
Lead uptake from air (fig/day)
Lead intake from diet (fig/day)
. Percent gastrointestinal absorption
Lead uptake from diet (jig/day)
Outdoor soil lead (us/a)
Indoor dust lead (jig/g)
Daily soil -dust ingest ion rate (ing/day)
Weighing factors (soil/dust)
Lead intake from dust and soil (fig/day)
Percent gastrointestinal absorption
Lead uptake from dust and soi I (jtg/day)
Drinking water lead. U.S. average Ug/l)
Drinking water intake (I/day)
Lead intake from drinking water (jig/day)
Percent gastrointestinal absorption
Lead uptake from drinking water (tig/day)
Value
0.04*
0.032*
3
0.033
4.5
0.14
32
0.045
6.38
50
3.19
15 to 2700*
" 15 to 2700*
100
45/55
Variable
30
Variable
4 .
0.48
1.92
50
0.96
* Site specific parameters. All others are EPA default values.
Source: adapted f row USEPA Technical Support Document on Lead, ECAO-CIH-757, Jan. 1991,
(Do Not Cite or Quote).
Definitions: UBK = Uptake Biokinetic Model, jig/m3 = micrograms per cubic meter,
mVday * cubic meter per day, jig/day = microgram per day,
jtfl/g = microgram per gram or parts per million (ppm),
mg/day - milligram per day, jig/I = microgram per liter, I/day = liter per day.
-------
Table 9
ESTIMATED LEAD UPTAKE BY CHILDREN1
IN STUDY AREA
Soil
Concentration
(ma/kg)
20s
250«
380
485
555
700
880
1060
1480
2700
Approximate
Percent! lett
NA
42
50
60
70
80
90
95
98
100
Pathway Specific Intake5
Air
(»9/day)
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.045
Water
(Kg/day)
0.96
0.96
0.96
0.96
0.96
0.96
0.96
0.96
0.96
0.96
Diet
(M/day)
3.19
3.19
3.19
3.19
3.19
3.19
3.19
3.19
3.19
3.19
Soil/Dust
(so/day)
0.6
7.5
11.4
14.55
16.65
21.0
26.4
31.8
44.4
81.0
Total
Intakt
Ug/day)
4.8
11.7
15.6
18.7
20.8
25.2
30.6
36.0
48.6
85.2
a Zero to six year-old children
b Ranked for 41 data points (Remedial Investigation and Field Investigation Report)
c Based on DDK model output for specific soil concentrations
d Typical western U.S. soil background lead concentration
e Upper-percentile urban background lead concentration
NA = Not included as one of the 41 data points
Definitions: mg/kg = milligram per kilogram or parts per million (pprn),
fig/day = microgram per day
-------
Table 10
ESTIMATED UPPER BOUND LIFETIME CANCER RISKS
FROM EXPOSURE TO ARSENIC*
Exposure Pathway
Estimated Cancer Risk b
Air inhalation: (lung cancer)
Air at 3.0 nanograms/cubic meter
5x10"
Ingestion by: (skin cancer:
Soil/house dust at 800 ppm
Garden vegetables at 800 ppm soil
3 classes c
5 classes d
Slag/house dust
Slag at 10.000 ppm
House dust at 100 ppm
Pica soil/house dust at 800 ppm
2X1Q-3
5x10'5
1 X1Q-3
4X10"3
Dermal absorption: (skin cancer)
Soil at 800 ppm
7x 10
,-5
a Estimated cancer risk* will vary depending on the soil arsenic concentration in individual yards. In this table, cancer
risks at 800 ppm soil arsenic are used as an example to show the reasonable maximum exposure - the highest exposure
reasonably expected to occur. Only five percent of the Study Area is expected to have soil arsenic concentrations
exceeding 800 ppm. Risks will be less for those areas with lower soil arsenic concentrations.
b The cancer potency factor (slope factor) used for calculating risks for the ingestion and dermal absorption exposure
pathways is 1.75 per mg/kg/day. The cancer potency factor (slope factor) used for calculating risks for the air inhalation
exposure pathway is 50 per mg/kg/day. These factors were taken from the Integrated Risk Information System (IRIS).
c Fruity, leafy, and root
d' Fruity, leafy, root potatoes, and legumes.
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Table 11
ESTIMATED LIFETIME NONCANCER RISKS FROM EXPOSURE TO ARSENIC*
Exposure Pathway
Hazard Quotient*
Ingest ion by:
Soil/house dust at 800 ppm
Garden vegetables at 800 ppm soil
3 classes0
5 classesd
Slag/house dust
Slag at 10,000 ppm
House dust at 100 ppm
Pica soil/house dust at 800 ppm
2.9 to 7.8
0.1 to 0.2
0.3 to 0.9
2.2 to 5.8
6.0 to 16.0
Dermal absorption:
Soil at 800 ppm
0.1 to 0.3
a Estimated noncancer ri*k» will vary depending on the soil arsenic concentration in individual yards. In this table,
noncancer risks at 800 ppm soil arsenic are used as an example to show the reasonable maximum exposure • the highest
exposure reasonably expected to occur. Only five percent of the Study Area is expected to have soil arsenic concentrations
exceeding 800 ppm. Risks will be less for those areas with lower soil arsenic concentrations.
b As the Hazard Quotient rises above a value of '1', the potential for noncancer effects increases. A reference dose range
of 0.3 ug/kg/day to 0.8 ug/kg/day was used in calculating these hazard quotients. This reference dose range was taken
from the IRIS.
c Fruity, leafy, and root
d Fruity, leafy, root potatoes, and legumes.
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TABLE 12
REMEDIAL ACTION OBJECTIVES AND REMEDIATION GOALS
REMEDIAL ACTION
OBJECTIVES
Contaminant
Environmental Media
Arsenic
Soil
Lead
Soil
Exposure Pathway
Exposed Population
Remedial Action Objectives
for Arsenic and Lead
Direct contact and
incidental ingestion
Current and future
residents of north
Tacoma and Ruston
Direct contact and
incidental ingestion
Current and future
residents of north
Tacoma and Ruston
Reduce potential exposure of current and future
community residents to soil and dust so that these
exposures will be within acceptable risk levels.
Reduce the potential transport of soil contaminants
inside homes or other buildings where exposures
may occur.
REMEDIATION GOALS
Contaminant
Arsenic
Lead
Goal
Contaminant Concentrations
in Soil
Reduce arsenic
exposures to ensure
that the upper-bound
lifetime excess cancer
risk to an individual
is between 1(H and
10-6
Reduce exposures to
lead to ensure that no
individual has greater
than a 5 percent
chance of exceeding
a blood lead level
criterion of 10 M-g of
lead per deciliter of
blood (10 Lig/dL)
230 ppm of arsenic 500 ppm of lead
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TABLE 13
SUMMARY OF REMEDIAL ACTION ALTERNATIVES
Remedial Action
Technologies/Options
No action
Community protection measures
Sod/vegetation required
Underground utility construction implications
Temporary relocation
Soil cap
Asphalt cap (din alleys and parking areas)
Soil removal and backfill
Sampling to determine necessary depth of
excavation
Off-site disposal
Environmental monitoring®
Fencing steeply sloped areas
Preferred
Alternative
0
•
•
o
Feasibility Study Remedial Action Alternatives
1
No action
•
2
Limited
Action
•
3
Sod and
Asphalt Cap
•
•
•
•
•
•
•
4
One Foot
Excavation
and Onsite
Storage
•
•
O
•
•
•
O
•
•
5
One Foot
Excavation
and Offsite
Disposal
•
•
O
•
•
•
•
•
•
6
Excavation
to
Background
Levels
O
•
•
O
Note:
O
Indicates that technology is definitely applicable.
Indicates that technology may be applicable.
Environmental monitoring may be used to reassess the extent of contamination during the implementation of a remedy, to ensure the safety of cleanup personnel and residents during
remedial action, to aid in the determination of the effectiveness of the remedial actions, or to create a baseline against which u> measure exposure potential or reduction in lieu of
remedial action.
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TABLE 14
UNIT QUANTITY ESTIMATES FOR REMEDIAL ACTION LEVELS OF 230 ppm AND GREATER OF ARSENIC
AND 500 ppm AND GREATER OF LEAD
Item
Total number of acres as part of Alternative
Number of non-paved acres requiring remedial action*
Estimated number of residential lots included in action**
Soils removed/replaced at residential lots (cubic yards)***
Sod required as cover (square yard)
Soils removed from alleys and unpaved parking lots (cubic yards)
Fencing required (linear feet)
Asphalt cap cover for alleys and parking lots (square yard)
Number of years to completion
Preferred
Alternative
273
109
525
168,000
528,000
11,000
3,500
66,000
7 years
Alternative 3,
Asphalt
Capping and
Soddine
273
109
525
14,660
528,000
11,000
3,500
66,000
lyear
Alternatives 4
and 5,
Excavation
and Onsite
Storage &
Excavation
and Offsite
Disposal
273
109
525
176,000
528,000
11,000
3,500
66,000
7 years
Alternative 6,
Excavation
Until
Background
Concentrations
of Arsenic and
Lead are
Achieved
273
109
525
330,000
528,000
11,000
3,500
66,000
12 years
Note: For Alternative 3 removal and replacement volumes are based upon placement of a 1 inch sod layer which is estimated to result in the removal
of about two inches of soil over 50 percent of the area to be sodded.
For Alternatives 4 and 5 removal and replacement volumes are based upon a depth of excavation of 1 foot. The selection of 1 foot is based
upon experience gained at similar sites, but the actual depth of excavation during remedial action may vary from this value.
Value in table is approximately 40% of the total acreage. This fraction represents the portion of the tola! surface area not covered by homes, paved
roads, and sidewalks. A complete description of the derivation of this percentage value is provided in the text. Section 2.4 of the feasibility study.
Number of homes within the designated total area. Estimate was made through inspection of aerial photographs of the site taken in 1988.
Value represents volume of soil excavated and disposed. An equivalent volume of uncomaminatcd soil will be required as backfill.
* +
+ *
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Table 15
EVALUATION CRITERIA
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.
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 applicable or relevant and appropriate state and
federal laws?
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 toxicrty, 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. Implementabiltty - 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?
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Table 16
RUSTON/NORTH TACOMA - SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PART A: ALTERNATIVES AND CORRESPONDING ARARe
Description of FS Alternative
Alternative 1 -- No action.
Alternative 2 - Limited action.
Alternative 3 -- Containment of contaminated soil using asphalt
capping and sodding.
Alternative 4 •- Excavation of one foot of contaminated soil,
backfilling with clean/uncontaminated soil, temporary storage of
contaminated soil at Asarco smelter, and final disposal at a) Asarco
smelter, or b) permitted land disposal facility.
.Alternative 5 -- Excavation of one foot of contaminated soil,
backfilling with clean/uncontaminated soil, disposal at permitted
land disposal facility.
Alternative 6 -- Excavation of contaminated soil until background
concentrations of arsenic and lead are achieved.
Preferred Alternative/Selected Remedy -- Excavation of
contaminated soil to a maximum depth of 18 inches, backfilling with
clean/uncontaminated soil, disposal or beneficial use on-site (if .
allowable under smelter cleanup) or disposal off-site in accordance
with Ecology's final decision on petition for dangerous waste
exemption.
AnnlipzthilA nr rplpi/ant anrt annmnriata CAMI lirompntQ /AQADQ\ ..
number corresponds to summary of statutory or requlatory
requirements described below
ARARs are not triggered for 'no action* alternative:
Under MTCA (see no. 2), limited action, or an action that relies
primarily on inconstitutional controls or monitoring, is not
acceptable where it is technically possible to implement a cleanup
action alternative that utilizes a higher preference cleanup
technology. If a component of a limited action remedy includes a
soil collection service, see disposal requirements under no. 1 .
See nos. 2. 5, 6, 7, 8, and 9. To the extent that excavation is
conducted, see also 1 , 3, and 4.
See nos. 1 through 9.
See nos. 1 through 9.
See nos. 1 through 9.
See nos. 1 through 9.
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Table 16
RUSTON/NORTH TACOMA - SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PARTS: THE ARARf EXPLAINED
Statute or Regulation
Status
Requirement
(1) Dangerous Waste Regulations (WAC
173-303); Minimum Functional Standards
for Solid Waste Handling (WAC 173-304).
Applicable to disposal of soil with
concentrations of arsenic above 100 ppm
(WAC 173-303-103).
Relevant and appropriate to construction of
storage or disposal areas on the smelter
site (if allowable under smelter cleanup).
State's area of contamination policy is a to-
be-considered (TBC) rather than an ARAR.
WAC 173-303-141 requires that dangerous
waste be taken to treatment, storage, or
disposal (TSD) facility with RCRA permit or
interim status authorization or facility that
will legitimately treat or recycle waste.
[Note: Shaded language describes how
the selected remedy will attain the
requirements Identified as applicable or
relevant and appropriate.)
Ecology is evaluating Asarco's petition for
exemption from the DW regulations, EPA
expects that Ecology's decision on the
exemption, when issued, will specify
requirements for disposal of Ruston soil In
an off-site facility. Ecology's dangerous
waste requirements win be attained through
compliance with Ecology's final decision.
State's area of contamination policy states
that dangerous waste may be consolidated,
contained, or treated within the area of
contamination without triggering the
applicability of final disposal requirements,
but such requirements may be relevant and
appropriate.
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Table 16
RUSTON/NORTH TACOMA - SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PART B: THE ARARa EXPLAINED (Continued)
Statute or Regulation
Status
Requirement
WAC 173-303-660 specifies that "waste
piles' (i.e., storage areas) shall be (1)
covered to prevent wind dispersal and to
prevent infiltration of rainfall, (2) include
run-on and run-off control systems, and (3)
include a drainage system to collect
leachate within the pile. WAC 173-330-665
specifies requirements for landfills (i.e.,
disposal areas).
Waste that is not a dangerous waste (e.g.,
contaminated vegetation) but is removed as
a result of excavation should be disposed
at a municipal landfill in compliance with
minimum functional standards under WAC
173-304.
(2) Model Toxics Control Act
(MTCA)(70.105D RCW; WAC 173-340).
Applicable to cleanup of contaminated soil.
Cleanup standards are described in WAC
173-340-700-707 and -740. Cleanup
actions are described in WAC 173-340-360
(actions are ranked by preference -
treatment to disposal in landfill (on- or off-
site) to containment to institutional
controls). Institutional controls are
described in WAC 173-340-440.
For Ruston/North Tacoma site, EPA and
Ecology have interpreted MTCA to require
engineering methods (e.g., capping and/or
soil removal) for properties above 'action
-------
Table 16
RUSTON/NORTH TACOMA - SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PART B: THE ARARa EXPLAINED (Continued)
Statute or Regulation
Status
Requirement
levels' - arsenic concentration above 230
ppm and lead concentration above 500
ppm. 'Replacement* soil (re., soil that is
used to replace contaminated soil that is
removed) must be below concentrations
commonly found in urban areas -- 20 ppm
arsenic and 250 ppm lead.
Requirements under MTCA will be attained
by removing soil up to 18 Inches in depth
at properties that exceed action levels and
replacing it with soil that does not exceed
urban background levels.
For Ruston/North Tacoma site, MTCA
requires institutional controls for properties
with soil with arsenic concentration
between 20 and 230 ppm and properties
where soil above 230 ppm arsenic remains
b$Jow a cap of "clean* soil. This
requirement will be attained through
Implementation of an education program,
use of a database of sample results, and
other community protection measures (see
Section 9.10 of ROD).
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Table 16
RUSTON/NORTH TACOMA -- SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PART B: THE ARAR* EXPLAINED (Continued)
Statute or Regulation
Status
Requirement
(3) Clean Air Act - National Ambient Air
Quality Standards (NAAQS)(40 C.F.R. Part
50). State Ambient Air Quality Standards
(WAC 173-470). Cleanup Standards To
Protect Air Quality (WAC 173-340-750).
Relevant and appropriate to activities that
may result in emissions of contaminants.
Requires that ambient concentrations of
lead not exceed 1.5 milligrams per cubic
meter based on quarterly average, that
particulates not exceed 50 micrograms per
cubic meter annually and not exceed 150
micrograms per cubic meter for any 24-
hour period. This requirement will be
attained through dust contra) measures
and monitoring during excavation activities,.
(4) Puget Sound Air Pollution Control
Agency (PSAPCA) Regulation 1.
Applicable to activities that may result in
emissions of fugitive dust and hazardous
contaminants, including arsenic.
Regulation 1 requires use of best available
control technology to control emissions of
fugitive dust. This requirement will be
attained through dust control measures
and monitoring during excavation activities.
(5) Surface water cleanup standards
(WAC 173-340-730); State water quality
standards for surface waters (WAC 173-
203).
Applicable to activities that may result in
discharges of contaminants into surface
waters.
Requires treatment, removal, or
containment measures to reduce
discharges of hazardous substances into
surface water (e.g., runoff from excavated
areas), consistent with water quality
standards for surface waters not to be
exceeded. This requirement will be
attained through drainage protection
measures and periodic monitoring of
surface water in order to ensure standards
are not exceeded as a result of cleanuff
actions.
-------
Table 16
RUSTON/NORTH TACOMA - SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PART B: THE ARARe EXPLAINED (Continued)
Statute or Regulation
Status
Requirement
(6) Coastal Zone Management Act (16
U.S.C. § 1451) and Shoreline
Management Act (90.58 RCW).
Applicable to development activities within
200 feet of shoreline.
Requires that development activities within
200 feet of shoreline be conducted in a
manner consistent with approved state
management programs. There are no
surface water bodies on or in the
immediate vicinity of the Study Area other
than seasonal storm water drainage swells
and gullies that flow into Commencement
Bay.
(7) EPA Policy on Wetlands (40 C.F.R.
Part 6, Appendix A). State designation of
wetlands (WAC 173-22-040).
Considered for activities involving wetlands.
Requires determination of whether wetlands
are present within site. If so, avoid adverse
effects, minimize potential harm, and
preserve and enhance wetlands to the
extent possible. State-designated wetlands
are regulated under the Shoreline
Management Act (see no. 6 above).
Whether wetlands are present will be
determined during remedial design/
remedial action,
(8) Endangered Species Act (16 U.S.C. §
1651).
Applicable to endangered or threatened
species or habitats. >
Requires determination whether
endangered or threatened species or
habitats are present within the site. If so,
procedures for conserving such species or
habitats must be followed. Whether
endangered or threatened species or
habitats are present will be determined
during remedial design/ remedial action.
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Table 16
RUSTON/NORTH TACOMA -• SUMMARY OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
PARTB: THE ARAR8 EXPLAINED (Continued)
Statute or Requlation
(9) National Historic Preservation Act (16
U.S.C. § 470). Archaeological Sites and
Resources Act (27.53 RCW).
Status
Applicable to properties included or eligible
for listing on the National or State Register
of Historic Places or properties .
Requirement
Requires determination of whether listed or
eligible properties are present within the
site. If so, procedures for preserving
properties or mitigating adverse effects
must be followed. Whether eligible
properties are present will be determined
during remedial design/ remedial action.
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Table 17
ESTIMATED COSTS OF REMEDIAL ACTION ALTERNATIVES (IN MILLIONS OF DOLLARS)
Alternative
2
3
4a
4b
5
6
Preferred
Capita) Cost
NA
$20
$49
$80
$75
$117
$78
O&M
$3
$7
$7
$7
$7
$2
$2
Total 1
$3
$27
$56
$87
$82
$119
$80
Total 2
$3
$24
$43
$67
$61
$85
$59
Notes for Table 17
Alternative 4a Costs are for temporary storage and permanent disposal at the Asarco smelter
facility.
Alternative 4b Costs are for temporary storage at the Asarco smelter facility followed by
permanent disposal at an authorized off-site facility.
Total r reflects estimated cost of disposal at a hazardous waste facility.
Total 2* reflects estimated costs of disposal at a non-hazan
are estimated to be less under Total 2* than under Total 1'
jous waste facility (i.e., capital costs
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APPENDIX A
RUSTON/NORTH TACOMA RESIDENTIAL STUDY AREA
RESPONSIVENESS SUMMARY
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