Commencement Bay Nearshore/
Tideflats Superfund Site
Asarco Sediments/Groundwater
Operable Unit 06
Ruston and Tacoma, Washington
Record of Decision
July 2000
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Contents
Page
Acronyms and Abbreviations v
PARTI DECLARATION
Site Name and Location 1
Statement of Basis and Purpose 1
Assessment of the Site 1
Description of the Selected Remedy 1
Groundwater 1
Sediment 2
Statutory Determinations 3
Data Certification Checklist 4
Authorizing Signature 4
PART II DECISION SUMMARY
Introduction 1-1
1 Site Name, Location, and Description 1-2
1.1 General Facility Description 1-2
1.2 Groundwater Conditions 1-3
1.3 Marine Sediments 1-4
2 Site History and Enforcement Activities 2-1
2.1 Historical Site Activities 2-1
2.2 Historical Enforcement Activities 2-1
2.3 Key Documents 2-3
3 Community Participation 3-1
4 Scope and Role of Operable Units 4-1
4.1 Selected Remedies for the Other Asarco OUs 4-1
4.2 Relationship of the OU 02 and OU 06 Remedial Actions 4-2
5 Site Characteristics 5-1
5.1 Production and Distribution of Slag 5-1
5.2 Contaminant Source Areas 5-1
5.3 Site Investigations 5-1
5.4 Groundwater 5-2
5.5 Marine Sediments and Environment 5-5
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CONTENS CONTINUED
6 Current and Potential Future Land and Resource Uses 6-1
6.1 Proposed Development Plans 6-1
6.2 Potential Groundwater Use 6-2
6.3 Marine Use 6-2
7 Summary of Site Risks 7-1
7.1 Human Health Risk Assessment 7-1
7.2 Ecological Risk Assessment 7-4
8 Remedial Action Objectives 8-1
8.1 Groundwater 8-1
8.2 Sediment 8-1
9 Description of Alternatives 9-1
9.1 Groundwater 9-1
9.2 Sediment 9-1
10 Summary of Comparative Analysis of Alternatives 10-1
10.1 Overall Protection of Human Health and the Environment 10-2
10.2 Compliance with Federal and State Environmental Standards 10-3
10.3 Long-Term Effectiveness and Permanence 10-4
10.4 Reduction of Toxicity, Mobility, or Volume Through Treatment 10-5
10.5 Short-Term Effectiveness 10-5
10.6 Implementability 10-6
10.7 Cost 10-7
10.8 State/Tribal Acceptance 10-7
10.9 Community Acceptance 10-8
11 Principal Threat Waste 11-1
12 Selected Remedy 12-1
12.1 Groundwater 12-1
12.2 Sediment 12-7
12.3 Expected Outcomes of the Selected Remedy 12-10
12.4 Summary 12-11
13 Statutory Determinations 13-1
13.1 Protection of Human Health and the Environment 13-1
13.2 Compliance with Applicable or Relevant and Appropriate Requirements
(ARARs) 13-1
13.3 Cost-Effectiveness 13-6
13.4 Utilization of Permanent Solutions and Alternative Treatment (or
Resource Recovery) Technologies to the Maximum Extent Practicable 13-6
13.5 Preference for Treatment as a Principal Element 13-7
13.6 Five-Year Review Requirements 13-7
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13.7 Documentation of Significant Changes from Preferred Alternative of
Proposed Plan 13-7
PART III RESPONSIVENESS SUMMARY
Introduction 1
Site Risk 2
Sediment Impact/Remediation Area 3
Alternatives to Sediment Capping 5
Protectiveness and Effectiveness of Sediment Capping Remedy 6
Sediment Cap Thickness 7
Sediment Dredging 11
Institutional Concerns Regarding Sediment Capping 15
Groundwater Extraction and Treatment 17
Remediation Goals/Levels (Groundwater) 17
Remediation Goals/Levels (Sediment) 24
Remedy Costs 26
Endangered Species Act and Biological Assessment Issues 26
Natural Resource Mitigation 27
Long-Term Monitoring 29
Other Comments 35
References R-l
D Comment Letters Received During the Proposed Plan Public Comment Period
Appendices
A Trend Plots of DMA-Related Organic Compounds
B Summary of Sediment Sampling Results
C Outcome of Preponderance of Evidence Approach for Marine Sediments
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CONTENS CONTINUED
Tables
5-1 Maximum Metal Concentration in Sediment
9-1 Groundwater Alternatives
9-2 Sediment Remedial Alternatives for the Nearshore/Offshore Area
9-3 Sediment Remedial Alternatives for the Yacht Basin (76,000 square yards; 15.5 acres)
9-4 Sediment Remedial Alternatives for the Northshore Area (7,000 square yards;
1.5 acres)
12-1 Groundwater Cleanup Levels
12-2 Sediment Cleanup Levels for the Yacht Basin
Figures
1-1 Asarco Facility Location Map
1-2 Operable Unit 06 Site Boundary
1-3 Former Facility Layout
1-4 Conceptual Cross Section
1-5 Habitat Areas Defined by Benthic Infauna Sampling
5-1 Source Areas and Selected Remedy
5-2 Monitoring Well Locations
5-3 Slag Wells, Dissolved Arsenic in Groundwater, September 1999
5-4 Intermediate Wells, Dissolved Arsenic in Groundwater, September 1999
5-5 Slag Wells, Dissolved Copper in Groundwater, September 1999
5-6 Intermediate Wells, Dissolved Copper in Groundwater, September 1999
5-7 Box Plots for Arsenic and Copper, Slag Wells
5-8 Box Plots for Arsenic and Copper, Intermediate Wells
5-9 Arsenic and Copper Trend at Well MW-139A
5-10 Sediment Station Locations
5-11 Sediment Chemistry Comparison to State SMS Criteria
5-12 Summary of Bioassay Results that Exceed One or More State SMS Criteria
7-1 Cleanup Level Evaluation Areas OU 06
9-1 Contaminant Effects Area
9-2 Marine Sediment Remedy Units
12-1 Selected Remedy, Marine Sediment
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Acronyms and Abbreviations
AKART all known available and reasonable methods of treatment
AOC Administrative Order on Consent
ARAR applicable or relevant and appropriate requirement
BMPs Best Management Practices
CAD confined aquatic disposal
CB/NT Commencement Bay Nearshore/Tideflats (Superfund Site)
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
of 1980
COC chemicals of concern
CSF cancer slope factor
CSL cleanup screening level
DMA Dimethylaniline or N, N-d i me thy 1 a n i 1 i n e
DNR Washington State Department of Natural Resources
Ecology Washington State Department of Ecology
EPA U.S. Environmental Protection Agency
ESD Explanation of Significant Difference
FS Feasibility Study
ft/ sec feet per second
IRIS Integrated Risk Information System
m/sec meter per second
MCL maximum contaminant levels
MHHW mean higher high water
MSL mean sea level
MTCA Model Toxics Control Act
NCP National Contingency Plan
NOAA National Oceanic and Atmospheric Administration
NPDES National Pollution Discharge Elimination System
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ACRONYMS AND ABBREVIATIONS
NPL
National Priorities List
NTR
National Toxics Rule
O&M
operation and maintenance
OMMP
Operation, Maintenance, and Monitoring Plan
OU
Operable Unit
PQL
practical quantitation limit
PSAPCA
Puget Sound Air Pollution Control Authority
RAO
remedial action objective
RD/RA
remedial design/remedial action
RfD
Reference Dose
RI
Remedial Investigation
RI/FS
Remedial Investigation/Feasibility Study
SARA
Superfund Amendments and Reauthorization Act of 1986
SMS
Sediment Management Standards
SQS
Sediment Quality Standard
TDS
total dissolved solids
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PARTI
Declaration
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PARTI
Site Name and Location
Commencement Bay Nearshore/Tideflats (CB/NT) Superfund Site
Asarco Sediments/Groundwater Operable Unit 06
Tacoma and Ruston, Washington
U.S. Environmental Protection Agency (EPA) ID No. WAD980726368
Statement of Basis and Purpose
This decision document presents the Selected Remedy for Asarco Sediments/Groundwater
Operable Unit 06 (OU 06) in Tacoma and Ruston, Washington. The Selected Remedy was
chosen in accordance with Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and, to the extent practicable, the National
Contingency Plan (NCP). This decision is based on the Administrative Record for this Site.
The State of Washington Department of Ecology (Ecology) concurs with the Selected
Remedy.
Assessment of the Site
The response action selected in this Record of Decision (ROD) is necessary to protect public
health, welfare, or the environment from actual or threatened releases of hazardous
substances into the environment. Such a release or threat of release may present an
imminent and substantial endangerment to public health, welfare, or the environment.
Description of the Selected Remedy
The Asarco Sediment/Groundwater Operable Unit (OU 06) Site ("Site") is one of the
operable units that specifically addresses contamination coming from, or related to, the
Asarco Smelter Facility ("Facility") in Ruston and Tacoma, Washington. The Selected
Remedy for the Asarco Sediments/Groundwater Operable Unit 06 includes the following
elements:
Groundwater
Groundwater at the Asarco Facility was originally studied in an RI/FS concluded in 1993
(Hydrometrics, August 1993). The Asarco Tacoma Smelter ROD (OU 02 ROD) identified the
selected remedy for onsite waste materials, contaminated soil, and surface water (EPA,
1995). However, the OU 02 ROD deferred a remedy decision for groundwater and called for
further monitoring. This ROD for OU 06 identifies the Selected Remedy for groundwater.
Although the Selected Remedy for groundwater was not addressed by the OU 02 ROD, a
number of elements in the OU 02 remedy will directly benefit groundwater quality. These
elements include capture of shallow groundwater in selected areas, construction of a low-
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PARTI
permeability cap across the Facility, and excavation of the most highly contaminated source
materials (selected slag material and contaminated soils) and consolidation of these
materials into an On-site Contaminant Facility. These OU 02 remedy elements will
(1) remove a significant source of contamination that would otherwise impact groundwater
quality and (2) significantly reduce the flow of contaminated groundwater to
Commencement Bay by minimizing recharge of the shallow aquifer system (e.g., surface
water controls and the low-permeability cap will reduce infiltration).
EPA has determined that additional remedial actions, over and above those already being
implemented under OU 02, are not necessary to address groundwater under this ROD for
OU 06. As a result this ROD summarizes the elements of the remedy for OU 02 that will
benefit groundwater and identifies other elements of the groundwater remedy not
previously addressed. These other remedy elements include finalization of the groundwater
remedial action objectives (RAOs), identification of cleanup levels and groundwater point of
compliance, and long-term monitoring requirements.
Specifically, the Selected Remedy for groundwater, as represented by the RODs for OU 02
and OU 06, includes the following elements:
• Reduce groundwater flow and related contaminant loading to Commencement Bay by
removing the most significant source materials and limiting groundwater recharge to
aquifers beneath the smelter portion of the Facility. Groundwater control will be
achieved by intercepting groundwater with subsurface drains in selected locations,
diverting surface water and installing a low-permeability cap over the smelter portion of
the Facility. These controls will minimize infiltration and recharge of onsite aquifers.
(These remedy elements are being accomplished under OU 02 cleanup.)
• Continue to monitor groundwater to evaluate the long-term effects that the Facility
cleanup will have on future groundwater quality. (Addressed for the first time in this
ROD for OU 06.)
• Implement institutional controls to restrict future use of Facility groundwater.
(Addressed for the first time in this ROD for OU 06.)
Sediment
The Selected Remedy for marine sediments includes the following elements:
• Dredge contaminated sediment in the Yacht Basin and place the dredged sediment
beneath a low-permeability soil cap to be constructed on the upland portion of the
Facility (i.e., OU 02). The sediments will be contained under the low-permeability cap at
an elevation such that groundwater will not come in contact with the sediment.
• Monitor the dredged area in the Yacht Basin to verify that it does not become
recontaminated.
• Cap contaminated sediments in selected offshore areas.
• Monitor the sediment caps to confirm that they remain in place, continue to isolate the
underlying contaminated sediment, become recolonized with healthy biological
communities, and do not become recontaminated.
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PARTI
• Use institutional controls to prevent activities that could damage the sediment caps.
• Monitor the areas outside the capped and dredged areas to confirm that these areas
meet RAOs.
The Selected Remedy for the Asarco Sediments/Groundwater OU 06 has been chosen to
complement the remedy previously selected for OU 02 (EPA, March 1995). The OU 02
remedy is currently being implemented.
Statutory Determinations
The Selected Remedy is protective of human health and the environment, complies with
federal and state requirements that are applicable or relevant and appropriate to the
remedial action, is cost-effective, and utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable with the following exceptions. The federal
National Toxics Rule (NTR) standard for arsenic of 0.14 (J.g/L (40 CFR Section 131.36) is a
relevant and appropriate requirement for groundwater but is being waived for reasons
discussed in Part II of this ROD (Section 12.1.1 of the Decision Summary).
The Selected Remedy for OU 06 does not satisfy the statutory preference for treatment as a
principal element of the remedy for the following reasons:
• Groundwater. Groundwater treatment is not viable or cost-effective because source
materials remain on the Site. Further, a pump and treat remedy for containment
purposes would be inefficient due to the direct hydraulic connection that the Site
aquifers have with the waters of Commencement Bay. Treatment would require
groundwater extraction in perpetuity at very high pumping rates. The most significant
source of groundwater contamination is the slag material that is present below the water
table throughout most of the Facility. This source material will continue to leach
contaminants to groundwater. The Selected Remedy focuses on restricting recharge to,
and flow through, the affected water-bearing zones such that the volume of
groundwater discharged to Commencement Bay is reduced to the maximum extent
practicable.
• Sediments. Treatment technologies were evaluated for possible application to sediment
cleanup, but were not carried forward because: (1) there are currently no effective and
appropriate in situ treatment technologies (i.e., treating in place) for sediments similar to
those at the Site, and (2) any ex situ treatment would require significant material
handling (e.g., dredging, de-watering, transporting, processing) and treatment
processing at extreme cost (e.g., construction costs could be as high as $75 million to
$100 million), with little or no additional benefit to the effectiveness of the remedy.
Because the Selected Remedy will result in hazardous substances, pollutants, or
contaminants remaining onsite above levels that allow for unlimited use and unrestricted
exposure, a review will be conducted within five years after initiation of remedial action to
ensure that the remedy is, or will be, protective of human health and the environment.
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PARTI
Data Certification Checklist
The following information is included in the Decision Summary of this ROD (Part 2).
Additional information can be found in the Administrative Record for this Site.
• Chemicals of concern and their respective concentrations — Sections 5 and 7.
• Baseline risk represented by the chemicals of concern — Section 7.
• Cleanup levels established for chemicals of concern and the basis for these levels —
Section 12.
• How source materials constituting principal threats are addressed — Section 11.
• Current and reasonably anticipated future land use assumptions and current and
potential future beneficial uses of groundwater used in the baseline risk assessment and
ROD —Sections 6 and 7.
• Potential land and groundwater use that will be available at the Facility as a result of the
Selected Remedy—Section 6.
• Estimated capital, annual operation and maintenance (O&M), and total present worth
costs, and the number of years over which the remedy cost estimates are projected —
Sections 9 and 12.
• Key factors that led to selecting the remedy — Section 12.
Authorizing Signature
Chuck Findley Date
Acting Regional Administrator
[Original signed by Chuck Findley on July 14,2000]
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PART II
Decision Summary
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PART II
Introduction
This Decision Summary provides a description of the site-specific factors and analyses that
led to selection of the remedy for the Asarco Sediments/ Groundwater Operable Unit 06 at
the Commencement Bay Nearshore/Tideflats (CB/NT) Superfund Site. In identifying the
Selected Remedy, the U.S. Environmental Protection Agency (EPA) considered many
factors, including information about the Site background, the nature and extent of
contamination, the assessment of human health and environmental risks, and the
identification and evaluation of remedial alternatives.
The Decision Summary also describes the involvement of the public throughout the
Remedial Investigation/Feasibility Study (RI/FS) process, and the environmental programs,
regulations, and statutes that may relate to or affect the cleanup alternatives considered for
this Site. The Decision Summary concludes with a description of the Selected Remedy and a
discussion of how it meets the requirements of the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA), and to the extent
practicable, the National Contingency Plan (NCP).
This Decision Summary is presented in 13 sections as follows:
• Section 1 —Site Name, Location, and Description
• Section 2 — Site History and Enforcement Activities
• Section 3 — Community Participation
• Section 4—Scope and Role of Operable Units
• Section 5 — Site Characteristics
• Section 6 — Current and Potential Future Land and Resource Uses
• Section 7—Summary of Site Risks
• Section 8 — Remedial Action Objectives
• Section 9 — Description of Alternatives
• Section 10 — Summary of Comparative Analysis of Alternatives
• Section 11 — Principal Threat Waste
• Section 12—Selected Remedy
• Section 13 — Statutory Determinations
Documents supporting this Decision Summary are included in EPA's Administrative
Record for the CB/NT Superfund Site, Asarco Sediments/Groundwater Operable Unit 06.
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PART II SECTION 1
1 Site Name, Location, and Description
The former Asarco copper and lead smelter facility (the "Facility") is located along the
Commencement Bay shoreline in Tacoma and Ruston, Washington (Figure 1-1). The Facility
is part of the CB/NT Superfund Site. This ROD addresses the Asarco Sediments/
Groundwater Operable Unit 06 (OU 06 or the "Site") at the Facility. The general boundary
of OU 06 is shown in Figure 1-2. OU 06 is one of four OUs associated with the Facility.
Additional information on the Facility OUs and their interrelationships is provided in
Section 4. OU 06 is also one of seven OUs located within the larger CB/NT Superfund Site.
The CB/NT Superfund Site was nominated to the National Priorities List (NPL) in 1982 and
placed on the final NPL in 1983. The EPA identification number for the Site is
WAD980726368.
EPA is the lead regulatory agency for the Site. The Washington State Department of Ecology
(Ecology) has supported the EPA at the Site throughout the CERCLA process. One
responsible party, Asarco, has publicly acknowledged its intent to conduct the cleanup for
OU 06; however, a consent decree for the cleanup of OU 06 has not yet been negotiated.
1.1 General Facility Description
The Facility is located within the municipal boundaries of Ruston and Tacoma, Washington.
The site is located on the northeast side of the Point Defiance Peninsula and borders
Commencement Bay (Figure 1-1). The general area consists of steep slopes extending down
to Commencement Bay producing bluffs along portions of the shoreline.
The onshore portion of the Facility is approximately 67 acres in size. In addition,
approximately 30 acres of offshore intertidal and subtidal lands are under Asarco
ownership. The State of Washington also owns a portion of the offshore lands within OU 06.
State-owned aquatic lands are managed by the Washington State Department of Natural
Resources.
Surface water features within the Facility boundaries include springs and seeps which
emanate from the face of the shoreline bluff from shallow groundwater bearing strata, and
impoundments in drainage bottoms south and west of the main plant complex. Elevation
across the Facility ranges from sea level to as high as 250 feet above mean sea level (MSL).
Steep drainages are located in the vicinity of railroad tracks that cross the Facility in an east-
west direction. There are areas of dense vegetation, primarily on steep drainage slopes and
along the bluff slope above Commencement Bay.
Much of the Facility was constructed on slag fill, a waste byproduct of smelting arsenic- and
lead-bearing ores. The slag fill was used to modify and extend the pre-existing shoreline by
approximately 500 feet into Commencement Bay. In addition, the Breakwater Peninsula (see
Figure 1-2) is composed of slag. The slag beneath the Breakwater Peninsula is up to 125 feet
thick (Hydrometrics, January 1993). See Section 5.1 for additional information on the
production and distribution of slag.
Prominent surface features on the Facility included a 562-foot-high stack and numerous
buildings and structures associated with copper smelting and refining. The stack and most
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PART II SECTION 1
of the buildings have been demolished in recent years. A car tunnel, a railroad tunnel, and a
pond formerly used for storage of process cooling water (the Cooling Pond) remain on the
Facility. Also onsite is the Fine Ore Bins building, which is currently used to store
demolition debris and contaminated soil that will eventually be moved to an onsite waste
containment facility being constructed as part of the OU 02 remediation. The former Facility
layout is depicted in Figure 1-3.
Surrounding land use is primarily suburban residential or recreational (Tacoma Yacht Club
and Point Defiance Park) with commercial land uses nearby. Areas south and west of the
plant complex consist primarily of single family residences. Shoreline areas to the southeast
were previously industrial, but are currently developed as park areas, public fishing areas,
and restaurants.
1.2 Groundwater Conditions
OU 06 includes groundwater beneath the Facility. The local occurrence and movement of
groundwater on the Point Defiance Peninsula is dictated by the distribution and properties
of glacially derived sediments that dominate the area geology. Glacial outwash deposits
consisting of relatively clean sand and gravel form groundwater flow pathways. The
complex glacial stratigraphy results in a number of isolated perched aquifers in the more
permeable units separated by less permeable tills and lacustrine deposits. The fine-grained
lacustrine sediments of the Kitsap Formation underlie the near-surface glacial outwash
deposits and consist of silt and clay with few gravelly zones. The Kitsap Formation is not a
groundwater flow pathway.
Shallow and deep aquifer systems1 have been identified at the Facility (Figure 1-4). The
deep aquifer is located approximately 70 to 100 feet below ground surface. The shallow
aquifer is located within 10 to 50 feet of the ground surface. The deep and shallow aquifers
are separated by the thick, low-permeability silt and clay of the Kitsap Formation. This low-
permeability zone inhibits groundwater flow between the shallow and deep aquifer
systems. Depending on location and depth, the shallow aquifer generally consists of sand
and gravel alluvium (in the higher elevations in the southwestern portion of the upland
Facility), slag fill (ranging up to approximately 45 feet thick near the shoreline), and native
marine sands (underlying the slag). The shallow aquifer system beneath the Facility is
largely recharged by infiltration of precipitation and surface water run-on and, to a minor
extent, by lateral flow of groundwater from the southwest (Ruston area).
Groundwater beneath the Facility generally flows in a northeasterly direction toward
Commencement Bay, the ultimate groundwater discharge point. Some shallow
groundwater discharges to the ground surface as seeps and springs in the upper elevations
of the site, specifically along the steeper slopes on the southwest side of the Facility.
1 Various Site documents reference the slag, marine sand, and intermediate aquifers. All of these aquifers are considered to
be within the "shallow aquifer system" as the term is used in this ROD.
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PART II SECTION 1
1.3 Marine Sediments
OU 06 includes marine sediments that extend approximately 1,000 feet offshore into
Commencement Bay. Intertidal and subtidal slopes range from relatively flat to steep
inclines (slopes to approximately 50 percent). The steepest submarine slopes were generally
formed by placing molten slag directly into the water where it hardened in massive forms.
Water depths in the steepest gradient areas within OU 06 are up to approximately 300 feet
deep.
Current patterns and water circulation in and around OU 06 were investigated as part of the
Draft Phase 2 Refinement of Options Report - Expanded Remedial Investigation and Feasibility
Study (Parametrix, December 1996) and the draft Biological Assessment (BA) of the Site
(Parametrix, May 2000). Strong, tidally generated currents are characteristic of the area.
Analysis of storm wave and tidal current conditions at the Site shows currents as high as
3.3 feet per second (ft/sec), or 1 meter per second (m/sec), occur near the bottom with tidal
and wave forces acting in the same direction. Nearshore tidal currents could be higher, up
to 4 ft/sec (1.24 m/sec.). The predominant flow patterns are westerly north of the Facility
and southeasterly to the south of it. Water movement within the Yacht Basin is considerably
less than that within adjacent areas outside the basin.
The marine sediments of interest occur in an area directly offshore of the Facility, extending
into Commencement Bay. These sediments, seaward of the Facility, generally consist of
coarse-grained material. Sediments inshore of the Breakwater Peninsula (Figure 1-2) in the
Yacht Basin, tend to be more fine-grained.
Aquatic habitats in OU 06 include shallow and deep subtidal coarse sediment (including
slag material), sand (with some slag particles), and mud communities. The coarse sediment
habitats, particularly in the areas of larger slag particles function as rock and gravel
substrates attracting fauna such as sea urchins, crab, shrimp, anemones, and scallops. The
sandy sediment habitats include aquatic communities composed of tube-dwelling
organisms, burrowing animals, and mobile epifauna (e.g. sea cucumbers, sea stars, sea
urchins, snails and crabs). The mud habitats are characterized by burrowing and sediment-
eating organisms. Figure 1-5 presents the locations of these habitats within OU 06.
Fish species commonly observed in the nearshore areas include juvenile and adult sanddabs
(iCitharichthys sp.), rock sole (Lepidopsetta bilineata), C-O sole (Pleuronichthys coenosus), English
sole (Parophrys vetulus), buffalo sculpin (Enophrys bison), staghorn sculpin (Leptocottus
armatus), striped surf perch (Embiotica lateralis), shiner surf perch (Cymatogaster aggregata),
pile perch (Rhacochilus vacca), Pacific herring (Clupea harengus pallasi), gunnels (Pholis spp.)
and mosshead warbonnets (Chirolophis nugator).
Macroflora commonly observed at the Site include red algae (Callophyllis edentata, Gigartina
sp. Indet., and Porphyra sp. Indet.) and green algae (Ulva, Monostroma and Enteromorpha
spp.), and kelp (Laminaria saccharina and Nereocystis leutkeana).
Listed and proposed threatened and endangered species that may be present within the
general project area include:
• Chinook Salmon, Puget Sound Stock (Oncorhynchus tshawytscha) — Threatened
• Coho Salmon, Puget Sound Stock (O. kisutch) — Candidate species for listing
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PART II SECTION 1
• Sea-run Cutthroat Trout (O. clarki clarki) — Proposed Threatened
• Bull Trout (Salvelinus confluentus) — Threatened
• Humpback Whale (Megaptera novaeangliae) — Endangered
• Steller Sea Lion (Eumetopias jubatus) — Threatened
• Leatherback Sea Turtle (Dermochelys coriacea) — Endangered
Of these, chinook salmon are considered to be a species of concern because the juveniles are
expected to occur along the shoreline of the Site during their outmigration period (i.e., from
February through July).
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PART II SECTION 2
2 Site History and Enforcement Activities
2.1 Historical Site Activities
From 1890 through 1912, the Facility was a lead smelter and refinery. Asarco, Inc.,
purchased the property in 1905. By-products of the smelting operations were refined to
produce other marketable products, such as arsenic, sulfuric acid, and liquid sulfur dioxide.
Asarco ended operations at the Facility in 1986.
The following is a brief chronological summary of operations at the former Asarco Tacoma
Complex:
1890 —Under ownership of the Tacoma Smelter Company, operation as a lead smelter
commenced.
1902—Copper production commenced.
1905—Asarco purchased the smelter.
1917—The plant was rebuilt, a stack was constructed, and electrostatic precipitators were
added.
1930 —The blast furnace smelting operations were discontinued and replaced with
reverberatories that produced slag as a by-product.
1974 —A liquid sulfur dioxide plant began operation, using a dimethylaniline process.
1977—A baghouse was installed to handle dust from the arsenic kitchen and metallic
arsenic plant.
1979 — The electrolytic refinery ceased operation.
1985 — Copper smelting operations were discontinued.
1986 —Arsenic production was discontinued, and the Facility ceased all manufacturing
operations.
Since 1987, Asarco has completed two phases of demolition activities at the Facility.
Structures in the stack area associated with copper smelting and the production of both
arsenic trioxide and metallic arsenic were demolished in 1987 and 1988. The majority of the
remaining buildings and structures, including the smelter stack, were demolished during
the period of 1992 to 1994. Much of the Facility (where historical manufacturing processes
were located) has been leveled and, to some extent, graded. Remedial actions required by
the OU 02 ROD began in 1999 when construction of the On-Site Containment Facility began.
The remaining remedial action required for OU 02 and OU 06 (this ROD) will extend
through 2005.
2.2 Historical Enforcement Activities
The history of regulatory activities affecting the former Asarco Tacoma Smelter began in the
late 1960s with the passage of air emission standards by the Puget Sound Air Pollution
Control Authority (PSAPCA). Although PSAPCA began regulating sulfur dioxide and
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PART II SECTION 2
arsenic emissions in 1968, variances to the standards were granted to Asarco until 1975. EPA
requirements such as National Pollution Discharge Elimination System (NPDES) permits,
which regulate point source water discharges, were applied in 1975. EPA also began
enforcement proceedings in the early 1980s to regulate air emissions. Federal and state
standards and variances continued to be issues of contention until the smelter closed in the
mid-1980s.
In July 1983, EPA issued proposed standards for arsenic under Section 112 (National
Emission Standards for Hazardous Air Pollutants) of the Clean Air Act. Inorganic arsenic
had been designated as a hazardous air pollutant in 1980 and the Asarco Smelter was a
major source of arsenic. The proposed standard for Asarco was modified to require better
management practices in handling arsenic-contaminated materials. These regulations were
never implemented due to a decision by Asarco to cease copper refining in 1985.
In September 1986, Asarco signed an Administrative Order on Consent with EPA pursuant
to Section 106(a) of CERCLA, in which Asarco agreed to conduct a Remedial Investigation
and Feasibility Study (RI/FS) and to perform immediate site-stabilization activities. Asarco's
contractors began the RI/FS in 1987 under EPA oversight. Site stabilization, Phases I and II,
were both conducted based on the information collected during the initial investigation of
the Facility.
In December 1990, EPA issued a ROD for demolition of structures and construction of a
surface water diversion system. Asarco agreed to perform this work in a Consent Decree
dated May 18,1992.
The field investigation and evaluation of remedial alternatives for a final RI/FS for OU 02
(including groundwater) was concluded by Asarco in 1993. The RI for the offshore marine
sediments was concluded in 1996; the FS process was concluded in 2000. The results of both
RI/FS processes were used to develop the remedy for OU 06.
The following is a brief chronological summary of CERCLA enforcement activities
associated with the former Asarco Tacoma smelter.
1986 Administrative Order on Consent (AOC) for RI/FS and Phase I site stabilization
signed.
1988 Phase I site-stabilization (demolition) activities completed.
1989 Draft RI/FS submitted.
1989 AOC for Expedited Response Action in Ruston/North Tacoma signed.
1990 Notice of Violation for RI/FS issued.
1990 Interim ROD for Phase II site-stabilization (demolition) and surface water controls
issued.
1991 Additional investigation of soil and groundwater contamination commences.
1992 Notice of Violation resolved.
1992 Consent Decree for demolition entered in federal court.
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PART II SECTION 2
1993 Two stipulated penalties for late draft FS submittals paid by Asarco.
1993 ROD for Ruston/North Tacoma Study Area issued.
1993 Unilateral Administrative Order for Ruston/North Tacoma Study Area issued.
1993 Final RI/FS report for OU 02 (including groundwater) submitted and approved.
1994 AOC for Groundwater, Surface Water, Soil and Marine Sediments monitoring and
sampling signed.
1995 ROD for OU 02 signed.
1996 Remedial Design for OU 02 initiated.
1996 Phase 1/Phase 2 Expanded RI/FS Sediment Activities completed.
1997 Placement of pilot cap in a small portion of the offshore contaminated sediments
area.
1999 Asarco Sediment/Groundwater Task Force concludes their evaluation of potential
groundwater impacts to Commencement Bay waters and sediments.
1999 Remedial Action for OU 02 initiated.
2000 Year 2 Pilot Cap Monitoring Report completed.
2000 Refinement of the Proposed Remedy Report completed.
2.3 Key Documents
Documents related to the RI/FS for OU 06 are available in the Administrative Record. Key
documents include the following:
• Historical Summary of the Evaluation of Groundwater Remedial Alternatives, Asarco Tacoma
Smelter Site (Hydrometrics, June 2000)
• Documentation of the Feasibility Study Process for the Sediments Portion of the Asarco
Sediments Operable Unit (Parametrix, January 2000)
• Refinement of the Proposed Remedy Report (Parametrix, January 2000)
• Copper in Nearshore Marine Water, Technical Memorandum (Parametrix, June 1999)
• Group 5 Technical Memorandum, Asarco Sediment/Groundwater Task Force
(Hydrometrics, April 1999)
• Draft Phase 2 Refinement of Options Report, Expanded Remedial Investigation and Feasibility
Study (Parametrix, December 1996)
• Ecological Risk Assessment and Seafood Consumption Screening Risk Assessment (Roy F.
Weston, October 1996)
• Phase 1 Data Evaluation Report and Phase 2 Sampling and Analysis Approach, Asarco
Sediments Superfund Site, Expanded Remedial Investigation and Feasibility Study (Parametrix,
April 1996)
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PART II SECTION 2
• Phase 2 Refinement of Options Report, Asarco Sediments Superfund Site, Expanded Remedial
Investigation and Feasibility Study (Parametrix, December 1996)
• Draft Disposal Site Inventory (Parametrix, March 1995)
• Supplemental Feasibility Study - Commencement Bay Nearshore/Tideflats Asarco Sediment Site
(Roy F. Weston, Inc., October 1993)
• Asarco Tacoma Plant Remedial Investigation, Tacoma, Washington (Hydrometrics, August
1993)
• Asarco Tacoma Plant Feasibility Study, Tacoma, Washington (Hydrometrics, August 1993)
• Asarco Tacoma Plant Yacht Club Breakwater Remedial Investigation, Tacoma, Washington
(Hydrometrics, January 1993)
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PART II SECTION 3
3 Community Participation
Throughout the CERCLA process, EPA has taken steps to inform and involve the public in
activities at the Site. EPA conducted the activities summarized in this section because the
agency believes that community participation in the decision-making process is a key
element in achieving a successful remedy.
In addition to cleaning up contamination at the Site, the community has been very
interested in the future use of the property. EPA's primary mission is to identify a Selected
Remedy that protects human health and the environment. However, EPA believes this can
be accomplished while concurrently considering the future development potential of the
property.
In order to provide a variety of opportunities for public participation in the cleanup decision
process, EPA developed a communications strategy in 1993 for its activities related to the
overall Asarco Facility, including OU 6 which is addressed by this ROD. This strategy
supplemented the existing Community Relations Plan, which included the larger CB/NT
and South Tacoma Channel Superfund Sites.
EPA has complied with the specific requirements for public participation under CERCLA by
publishing a Proposed Plan for public comment. The Proposed Plan, Asarco
Sediments/Groundwater Operable Unit 06 (Proposed Plan) was published on January 26, 2000
(EPA, January 2000a). A fact sheet summarizing the Proposed Plan was also published at
that time. Both the Proposed Plan and fact sheet were made available at local information
repositories. The initial public comment period went from January 26 through February 25,
2000. In response to a request from the Washington State Department of Natural Resources,
the comment period was extended 30 days to March 27, 2000. During the comment period,
EPA held a public meeting in Ruston, Washington, on February 10, 2000. EPA also
published newspaper advertisements in the Tacoma News Tribune to announce the
availability of the Proposed Plan, the comment period, and the public meeting. Comments
received during the public comment period are summarized along with EPA's responses in
the Responsiveness Summary (Part 3 of this ROD).
In addition to the February public meeting and comment period addressing the Proposed
Plan for OU 06, the following outreach activities have been conducted by EPA in recent
years to inform the public about remedial activities at other related and adjacent operable
units (e.g., OU 02, Asarco Tacoma Smelter and Breakwater Peninsula, and OU 04, Asarco
Off-Property [Ruston/North Tacoma Study Area]):
• Small Group Meetings. EPA staff has attended meetings with groups upon request to
share information about the agency's cleanup proposal and to address the public's need
for information about the Facility. These groups include Black Collective Association,
Izaak Walton League, Association of Builders and Contractors, Tacoma Environmental
Commission, National Association of Women in Construction, Association of General
Contractors, American Institute of Architects Southwest Washington, Environmental
Task Force of Tacoma-Pierce County Chamber of Commerce, Kiwanis Club, and Rotary
Club.
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PART II SECTION 3
• Personal Interviews. In November 1993, EPA staff met with individual citizens to better
understand community concerns regarding the cleanup.
• Availability Sessions. In October, November and December 1993, EPA and Asarco held
sessions for citizens to visit one-on-one with EPA and Asarco staff to discuss cleanup
plans.
• Community Workgroup Briefing. On May 19,1994, EPA held a meeting for the
Ruston/North Tacoma Community Workgroup. This workgroup was formed in 1989 to
provide an avenue for citizens to become involved in residential investigation and
cleanup activities.
• Public Meetings. EPA held two public meetings in 1994 during the 90-day public
comment period for the Proposed Plan addressing OU 02. As indicated above, a public
meeting and 60-day public comment period were provided in early 2000 to present
information about and respond to any comments concerning the preferred remedy for
OU 06.
• Periodic Briefings. Briefings have been held for representatives from the Town of
Ruston, City of Tacoma, Tacoma Environmental Commission, the Office of
Congressman Dicks, and other interested local government officials.
• Information Repositories. EPA has established and periodically updates various local
document repositories where citizens can review detailed information about EPA's
Superfund activities. As new materials become available, they are added to these
repositories. Documents reflecting public comments can also be found in these locations.
The location and subject of the repositories are frequently advertised in fact sheets and
in newspaper notices prepared by EPA.
• Fact Sheets and Brochures. EPA has periodically distributed fact sheets to members of
the affected community to provide current information on the status of Facility
activities.
• Coordinating Forum. The Ruston/North Tacoma Coordinating Forum was formed in
March 1991 to facilitate discussion and coordination among the various entities involved
and/or affected by the Ruston/North Tacoma Residential Study Area project. In July of
1993, the Forum turned its attention to evaluating cleanup options for the Asarco
Tacoma Smelter.
To address issues associated with cleanup and future redevelopment of the Asarco
Smelter Facility, two subcommittees were formed from the Coordinating Forum. The
two subcommittees addressed land use and technical issues, respectively. The
subcommittees included members of the public and staff from regulatory agencies and
other government and private organizations. Both subcommittees worked for over a
year on issues related to developing a cleanup plan for the Facility. EPA participated
directly in the technical subcommittee and received input from the land use
subcommittee. Input from both of these subcommittees has been used by EPA to
develop both the OU 02 and OU 06 RODs. The following parties participated in the
subcommittees.
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PART II SECTION 3
Land Use Subcommittee
Asarco, Inc.
City of Tacoma
Metropolitan Parks District
Town of Ruston
Technical Subcommittee
Agency for Toxic Substances and Disease Registry
Citizens for a Healthy Bay
Community Representative
Environmental Protection Agency
Puget Sound Air Pollution Control Authority
Puyallup Tribe of Indians
Tacoma-Pierce County Health Department
U.S. Fish and Wildlife Service
Washington Fish and Wildlife Service
Washington Department of Ecology
Washington Environmental Council
Washington Department of Health
Members of the Land Use Committee
• Technical Assistance Grant. In 1991 EPA awarded a Technical Assistance Grant (TAG)
to the Citizens for a Healthy Bay. Citizens for a Healthy Bay has used these funds to hire
technical experts to review and comment on cleanup design documents, prepare
information for the general public on cleanup work, and prepare information for non-
English speaking people who may fish or work on Commencement Bay. Citizens for a
Healthy Bay maintains an office in downtown Tacoma which is open to the public and
serves as an information repository for the CB/NT Superfund Site. Citizens for a
Healthy Bay also publishes a quarterly newsletter that addresses a wide range of
environmental issues of potential concern to the citizens of Tacoma.
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PART II SECTION 4
4 Scope and Role of Operable Units
The CB/NT Superfund Site has been divided into seven OUs. Superfund sites are often
divided into OUs to more easily address individual areas within a large site, accommodate
differing site conditions and remedies, or schedule phases of investigations and cleanup
actions. Of the seven OUs designated within the CB/NT Superfund Site, four OUs are
associated with the Facility:
• OU 02, Asarco Tacoma Smelter and Breakwater Peninsula—Consists of the "upland"
portion of the former Asarco Smelter Facility. The media of primary concern are surface
water and soils (including mixtures of soil and waste materials).
• OU 04, Asarco Off-Property (Ruston/North Tacoma Study Area) —Consists of the
properties in Ruston and Tacoma adjacent to the Asarco Facility that have been
contaminated by airborne fallout of emissions from the former Asarco stack. The
medium of primary concern is soil.
• OU 06, Asarco Sediments/Groundwater—Consists of marine sediments located
offshore of the Asarco Smelter Facility and groundwater underlying OU 02. The marine
sediments in the Yacht Basin adjacent to the Facility are also included. The media of
primary concern are sediments and groundwater.
• OU 07, Asarco Demolition—Consists of the Asarco buildings and infrastructure (e.g.,
underground utilities) subject to demolition and within the boundaries of OU 02. There
are no environmental media associated with OU 07.
The approximate boundaries of OUs 02 and 06 are shown in Figure 1-2. The groundwater
portion of OU 06 extends beneath the entirety of OU 02, which is also indicated in
Figure 1-2.
4.1 Selected Remedies for the Other Asarco OUs
This ROD addresses the Selected Remedy for OU 06, Asarco Sediments/Groundwater. EPA
has previously selected the following remedies for the other three Asarco OUs.
4.1.1 OU 02, Asarco Tacoma Smelter and Breakwater Peninsula
The Selected Remedy for OU 02 focuses on removal of source materials (waste material and
highly contaminated soils) from the former Asarco Smelter Facility. The excavated source
materials are to be contained in an onsite engineered repository referred to as the On-Site
Containment Facility. Capping, surface water controls, shoreline armoring, and habitat
restoration in selected inter-tidal areas are also integral to the OU 02 remedy. The Facility
will be covered with a low-permeability cap to significantly reduce infiltration and
percolation of precipitation that would otherwise recharge the groundwater system. The
shoreline armoring will reduce the potential for erosion and transport of slag into
Commencement Bay where it could recontaminate sediments.
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PART II SECTION 4
4.1.2 OU 04, Asarco Off-Property
The Selected Remedy for OU 04 involves removal of arsenic- and lead-contaminated soils
from residential yards and public spaces in Ruston and North Tacoma. The remedial action
program began in 1994 and is ongoing.
4.1.3 OU 07, Asarco Demolition
The Selected Remedy for OU 07 included the demolition of buildings and other structures
within the boundaries of OU 02. At this writing, all demolition is substantially complete
with the exception of the Fine Ore Bins building. The Fine Ore Bins building is currently
used to stockpile demolition debris and contaminated soils destined for permanent
containment in the On-Site Containment Facility. The Fine Ore Bins building will be
demolished concurrent with future OU 02 remediation activities.
4.2 Relationship of the OU 02 and OU 06 Remedial Actions
EPA identified the Selected Remedy for OU 02 in a 1995 ROD (EPA, March 1995).
Remediation of OU 02 began in 1999 and will be essential to the successful cleanup and
long-term protection of groundwater and marine sediments included in OU 06. For
example, OU 02 contaminants leaching to underlying groundwater in OU 06 are
transported by prevailing groundwater flow to Commencement Bay where they are
discharged and threaten marine waters and sediments. Similarly, erosion and transport of
slag particles from the nearshore areas of OU 02 into Commencement Bay results in
deposition of these materials onto, and eventual mixing with, existing sediments.
Many elements of the OU 02 remedy will have direct benefits to the quality of groundwater
and marine sediments within OU 06. These beneficial elements include collection and
diversion of groundwater and surface water in selected areas to the surface water treatment
system, construction of a site-wide low-permeability cap, and removal of the mostly highly
contaminated source materials (selected slag material and contaminated soils). In particular,
the OU 02 remedy will significantly reduce the flow of contaminated groundwater to
Commencement Bay by minimizing recharge of the shallow aquifer system (e.g., surface
water controls and the low-permeability cap will reduce infiltration). An estimated 75 to
95 percent reduction in OU 06 groundwater flow and contaminant loading to
Commencement Bay is expected from the OU 02 remedy.
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PART II SECTION 5
5 Site Characteristics
Past smelting operations at the Asarco Facility have resulted in contamination of soil,
groundwater, surface water, and marine sediments. Wastes generated by the former
smelter, particularly slag, have acted as a continuing source of contamination to
groundwater and marine sediments.
5.1 Production and Distribution of Slag
Slag was produced as a waste product during the smelting of copper from arsenic- and lead-
bearing ores. The slag at the Site is generally composed of dark brown iron-rich silicates that
include metals such as arsenic, copper, and lead. The slag is similar in appearance to
volcanic rock. It is either massive or granular, depending on the way it was processed and
placed on the Site. Massive slag is present where molten slag was poured directly into the
waters of Commencement Bay. Contact with the cold water solidified the molten material in
place. Granular slag was intentionally produced by passing molten slag through cold water
streams to produce a sand- to gravel-sized material. This granular slag was then used as fill
material throughout the Facility. The slag was used to extend the shoreline by
approximately 500 feet outward into Commencement Bay. In addition, the Breakwater
Peninsula (see Figure 5-1) is comprised entirely of slag.
5.2 Contaminant Source Areas
In addition to the slag, principal threats to human health and the environment posed by the
Facility are the contaminated materials that occur within the six "source areas," as identified
in Figure 5-1. These areas contain buried waste materials and have either the highest
measured concentrations of contaminants in soils, are primary sources of contamination to
groundwater and sediments, and/or comprise large amounts of contaminated material
based upon the historical uses of these areas. These six areas are:
• Stack Hill
• Copper Refinery
• Cooling Pond
• Fine Ore Bins Building
• Arsenic Kitchen
• Southeast Plant Area
The slag material that underlies much of the Facility is characterized by high concentrations
of arsenic and other metals, which can also impact the groundwater and sediment. The
source materials in the above-referenced six areas are being addressed as part of the OU 02
remedial action and are therefore not covered by this ROD for OU 06.
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PART II SECTION 5
5.3 Site Investigations
Under EPA's oversight, Asarco began an RI/FS in 1987. The following OU 06 media were
investigated:
• Groundwater
• Marine sediments and biological environment
Marine sediment chemistry
Marine waters
Marine tissue (fish and benthic tissue)
Bioassays and benthic community structures
The RI/FS for groundwater was completed in 1993 and the RI/FS for sediments was
completed in 1996.
In 1996, EPA formed the Asarco Sediments Groundwater Task Force (Task Force) to address
the relationship between groundwater and sediment contamination. The Task Force
addressed two questions:
1. "Does groundwater that is discharging from the Facility negatively impact the marine
sediments and waters of Commencement Bay?"
2. "Would a sediment cap remain stable (e.g., stay in place) in the presence of strong
currents in this part of Commencement Bay?"
The first question was addressed by the Asarco Sediments Groundwater Task Force (Task
Force). The Task Force evaluated the impacts of discharging groundwater on the marine
sediments and waters of Commencement Bay. The second question was addressed by the
placement and monitoring of a pilot-scale sediment cap to determine how well the test cap
would physically remain in place over a 2-year period (Parametrix, February 2000). The
pilot-scale cap was constructed offshore of the Facility, immediately northeast of the Fine
Ore Bins building (Figure 5-1). The purpose of the cap was to determine the physical,
chemical, and biological characteristics of two sediment plots, one with a thickness of
30 centimeters and the other with a thickness of 60 centimeters.
The key site characterization findings relating to groundwater and marine sediments as
determined by the RI/FS, Task Force, and pilot-scale sediment cap study are summarized in
the following sections.
5.4 Groundwater
Groundwater conditions at the Asarco Facility were initially characterized in the late 1980s
and early 1990s during the RI for the upland portion of the Facility. Since that time,
monitoring of groundwater quality has continued throughout the Facility as part of the
post-RI Monitoring Program. (The post-RI monitoring program includes sampling selected
onsite wells on a bi-annual basis, usually in March and September.) A summary of
groundwater quality conditions as indicated by the results from the post-RI monitoring
program is provided below.
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PART II SECTION 5
5.4.1 Shallow Groundwater
Groundwater at the Site occurs in the shallow and deep aquifer systems as discussed in
Section 1 and depicted conceptually in Figure 1-4. Monitoring indicates that Site
groundwater flows from the southwest to northeast and ultimately discharges to
Commencement Bay. The general groundwater flow direction is depicted in Figure 1-4 and
5-1. Near the shoreline, groundwater levels constantly fluctuate in response to the tide in
Commencement Bay.
Groundwater has been adversely impacted by direct contact with contaminated source
materials or indirectly impacted by infiltrating waters transporting contaminants to
groundwater. In turn, Site groundwater discharges to Commencement Bay and the Yacht
Basin where the contaminants are released to the marine environment.
Figure 5-2 shows monitoring wells that either are, or have been, included in the post-RI
monitoring program. Groundwater in the shallow aquifer system is contaminated by
elevated concentrations of metals including arsenic, cadmium, copper, lead, nickel, and zinc.
Historical data show that distribution of elevated metals concentrations are generally well
represented by arsenic and copper results.
The natural groundwater background concentrations for arsenic and copper in the Tacoma
vicinity are 6 and 40 micrograms per liter (|j,g/L), respectively (EPA, April 1993). Arsenic
and copper have been detected above their respective background levels frequently. Arsenic
concentrations have exceeded the background level of 6 (ig/L in approximately 90 percent
of the groundwater samples collected since the RI. For copper, nearly 40 percent of the
samples have exceeded the background level of 40 (ig/L. With a marine chronic criterion of
3.1 (ig/L, copper is a concern with respect to the potential threat posed by groundwater
discharging to Commencement Bay waters. Approximately 60 percent of the groundwater
samples collected since the RI have exceeded the 3.1 (ig/L marine chronic criterion for
copper. Other metals also exceed applicable marine water or drinking water criteria, but less
frequently and usually where either arsenic or copper is also elevated.
Figures 5-3 through 5-6 depict isoconcentration contours for dissolved arsenic and copper in
the "slag" and "intermediate" wells based on samples collected during September 1999
(latest monitoring period for which data are available). Both the slag and intermediate wells
monitor the shallow aquifer system as depicted in Figure 1-4. The slag wells are screened in
slag and the intermediate wells are screened in either shallow alluvium, non-slag fill, or in
the marine sands underlying the slag. Figures 5-7 and 5-8 show box plots depicting the
range of arsenic and copper concentrations in the slag and intermediate wells during the
post-RI monitoring period (1994 to 1999).
As evident in the above-referenced figures, historical arsenic and copper concentrations in
groundwater range up to several tens of thousands of parts per billion in some locations.
Concentrations are highest in and around the former smelter processing areas. Metal
concentrations decrease approaching the Commencement Bay as evidenced by data from
nearshore monitoring wells and shoreline monitoring stations. (The shoreline monitoring
stations consist of sampling tubes located along the shoreline, which are intended to sample
groundwater as close as possible to the point of discharge to Commencement Bay and the
Yacht Basin.) September 1999 data for the shoreline monitoring stations indicate that arsenic
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PART II SECTION 5
concentrations range from 5 to 29 (ig/L (Figure 5-3) and copper concentrations range from 4
to 23 (ig/L (Figure 5-5). The reduction in metal concentrations near the shoreline is caused
by dispersion and attenuation of the contaminants as they move toward the bay. Dilution
effects due to seawater entering the nearshore portions of the aquifers also have a significant
impact on the reduction in metals concentrations.
Samples from the nearshore areas of Commencement Bay provide yet another indication of
how groundwater discharging from the site may be affecting marine surface water. Data
collected by Asarco in September 1999 show that existing (pre-remedial action) copper
concentrations in Commencement Bay water immediately adjacent to the slag shoreline face
are below the 3.1 (ig/L marine chronic criterion in most locations sampled. The exception is
the Yacht Basin where samples exceed the copper marine chronic criterion as far as 200 feet
from shore (measured copper concentration of 8.38 (ig/L based on average of high and low
tide samples collected in September 1999). This is not unexpected given the proximity of the
Yacht Basin to the defunct Copper Refinery Area (see Figure 5-1), a source of copper
contamination within the upland portion of the Facility.
The presence of oxygen in seawater that invades the nearshore portions of the aquifers has a
favorable impact on the fate of arsenic by promoting its precipitation. Copper, however,
responds differently than arsenic to the effects of the more highly oxygenated seawater.
Copper tends to be more readily mobilized from the slag into the groundwater when
dissolved oxygen levels increase; however, copper is still subject to dilution as groundwater
mixes with seawater as it approaches Commencement Bay. In spite of the increased
mobilization of copper in the presence of higher dissolved oxygen levels, the net effect is a
reduction in copper concentrations in groundwater approaching the shoreline due to the
dilution effect.
In the Southeast Plant Area (Figure 5-1), slag was placed over wood waste originating from
a former sawmill operation. Later, Asarco used an organic chemical called dimethylaniline
(N,N-dimethylaniline or DMA) in this area for the production of concentrated sulfuric acid
and liquid sulfur dioxide. Shallow aquifer groundwater in this Southeast Plant/DMA area
has some of the lowest pH values and highest copper and arsenic concentrations found at
the Site (Figures 5-3 through 5-6). DMA-related organic compounds, such as aniline, are also
present in the shallow aquifer system. Appendix A includes charts showing the trend of
various DMA-related compounds with time. As discussed above for arsenic and copper,
concentrations of DMA-related compounds are highest near the center of the Southeast
Plant/DMA area and decline significantly near the Commencement Bay shoreline. For
example, aniline is present at approximately 100,000 (ig/L near the center of the Southeast
Plant/DMA area (well MW-B37 in Figure 5-2) but is either not detected or detected at part-
per-billion levels in samples collected from nearshore monitoring wells located directly
downgradient. Data for DMA-related compounds are depicted graphically in Appendix A.
5.4.2 Deep Groundwater
In comparison to the shallow aquifer, elevated contamination of the deep aquifer is limited
in extent and concentration. Contamination in the deep aquifer is present near a former
production well that provided water for the Facility (see location in Figure 5-1). It is
believed that metals migrated from the shallow aquifer to the deep aquifer through the well
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PART II SECTION 5
casing. This well was sealed in 1994 to inhibit the movement of contaminants between the
shallow and deep aquifer systems. Arsenic and copper data from deep monitoring well
MVV-139A, located approximately 75 feet from the former production well, is shown in
Figure 5-9 and shows a decreasing concentration trend over the last 9 years.
5.5 Marine Sediments and Environment
Since the Asarco Facility was first included in the CB/NT Superfund Site, many studies
have been completed to characterize and assess the potential effects of sediment
contamination to human health and to the environment. In 1996, an expanded RI/FS
investigation of offshore sediments was completed to better define contaminant effects at
the site. Analyses of samples collected at the Facility as part of these investigations included
sediment chemistry (inorganic and organic chemical analyses), surface water chemistry,
pore-water chemistry, fish tissue analyses, benthic tissue analyses, bioassays, and benthic
community structure analyses. A brief summary of these results are provided below;
specific details can be found in Phase 1 Data Evaluation Report and Phase 2 Sampling and
Analysis Approach, Asarco Sediments Superfund Site, Expanded Remedial Investigation and
Feasibility Study (Parametrix, April 1996); Phase 2 Refinement of Options Report, Asarco
Sediments Superfund Site, Expanded Remedial Investigation and Feasibility Study, Appendix A -
Phase 2 Data Evaluation Report (Parametrix, December 1996); and Supplemental Feasibility
Study, Commencement Bay Nearshore/Tideflats Asarco Sediments Site (Roy F. Weston, Inc.,
October 1993).
5.5.1 Marine Sediment Chemistry
The Washington State Sediment Management Standards (SMS) are used to evaluate
contaminated sediments. The long-term goal of the SMS is "to reduce and ultimately
eliminate adverse effects on biological resources and significant health threats to humans
from surface sediment contamination." To this end, the SMS include numerical standards
for chemical and biological effects for the protection of marine animals living in the
sediments (the "benthic community").
The SMS defines two levels of chemical and biological criteria. The most stringent level, the
Sediment Quality Standard (SQS), corresponds to the long-term goal of "no adverse effects"
on the benthic community. The less stringent level, the Cleanup Screening Level (CSL),
corresponds to "minor adverse effects" on this community. At contaminant levels above the
CSL, more significant effects are predicted, and a sediment cleanup decision is required.
The chemical criteria are numerical values derived from Puget Sound test data. The test data
revealed specific adverse biological effects associated with chemical concentrations. Cleanup
areas may be defined using chemical criteria alone. However, the SMS recognize that the
chemical data may not accurately predict biological effects for all sediment locations.
Biological testing (bioassays and benthic evaluation), allowed under the SMS, can be
conducted to determine whether biological effects predicted by the chemical concentrations
are occurring. The biological testing must include two tests for acute toxicity to marine
organisms and one for chronic biological effects. If all three biological criteria are met for a
given area, this area is not included in the cleanup area and does not require cleanup under
the SMS for the protection of benthic organisms. Failure to meet the biological criteria,
confirms the potential for adverse impacts to the benthic community.
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PART II SECTION 5
During the Supplemental FS, 100 surface sediment stations were sampled for sediment
chemical data. During the Phase 1 Expanded RI/FS a total of 62 sediment stations were
sampled for chemical, physical and biological characteristics in order to identify an
appropriate remedy for sediments. An additional 10 subsurface sediment samples were
analyzed for chemistry and conventional parameters during the Phase 2 Expanded RI/FS.
Figure 5-10 presents the sediment station locations from which these samples were
collected.
Eleven inorganic chemicals were analyzed in surface sediment samples: arsenic, cadmium,
chromium, copper, iron, lead, manganese, nickel, silver, zinc, and mercury. Nine inorganic
chemicals were analyzed in the subsurface sediments: arsenic, cadmium, chromium, copper,
lead, nickel, silver, zinc, and mercury. Table B-l in Appendix B summarizes the inorganics
data obtained during the RI/FS. Tables B-2 and B-3 present the metals results from the
Expanded RI/FS Phase 1 and 2 data evaluations, respectively (Parametrix, April 1996 and
December 1996). Inorganics were detected in sediments at significant concentrations in areas
of the Site. Arsenic, cadmium, chromium, copper, lead, mercury, silver and zinc were found
in sediments at concentrations above the SMS. Chemicals of concern (COCs) in sediment
were determined to be arsenic, copper, lead, and zinc. These metals or metalloids were
contaminants with the highest concentrations encountered in surface and subsurface
sediments. Concentrations of arsenic found in sediment samples were as high as 26,410
milligrams per kilogram (mg/kg). Maximum concentrations of the other three COCs are
summarized in Table 5-1. Figure 5-11 presents the sediment station locations where samples
with sediment chemistry in excess of state cleanup criteria were collected. A significant
amount of slag was found in sediment samples off the Breakwater Peninsula and
immediately off the former smelter property. Slag contains the highest concentrations of
metals including arsenic and lead but in a rock-like form.
Although numerous sediment samples at the site contain high concentrations of metals and
metalloids, there is site-specific evidence (e.g., pore water chemistry, pore water bioassays,
sequential extraction of slag) that bulk sediment chemistry results are not indicative of
actual toxicity or are a reliable measure of the extent and magnitude of contaminant effects.
This is because the bioavailability of metals and metalloids in slag to potential receptors
may be low. Therefore the chemistry may have high concentrations yet the biological
community could be healthy.
Tables B-4 and B-5 in Appendix B summarize the organic compounds detected in
subsurface sediments from the Site. Out of 24 organic compounds tested, only individual
polynuclear aromatic hydrocarbons and phthalates (butyl benzyl and bis-2-ethylhexyl) were
detected above the SMS. No organic COCs were identified at the Site because the detections
of these compounds were isolated and did not suggest a defined area of contamination.
Furthermore, their limited occurrence corresponded to sediment sample stations that
exhibited inorganic chemical contamination. Therefore it is believed that remedial responses
for the inorganics would address incidental contamination by organics.
5.5.2 Marine Waters
Marine surface water samples have been collected from various locations offshore of the
Facility over a period of years. Recent sampling conducted in March, April, and September
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PART II SECTION 5
1999 indicates that only copper exceeds its corresponding marine chronic criteria for surface
water (Parametrix, June 1999; Hydrometrics, March 2000). Sediment pore-water samples
were previously collected from 11 stations at the Site and 2 reference stations in 1994 and
1995. The chemicals detected above EPA's marine acute and chronic criteria included
arsenic, copper, and ammonia (Parametrix, April 1996).Table B-6 in Appendix B presents the
chemistry results for sediment pore water.
5.5.3 Marine Tissue
Rock Sole (Lepidopsetta bilineata) whole fish and fillet samples were collected from five
sample stations at the Site and a reference site (Browns Point, east of the Site). The whole-
fish body results indicated consistent detections of arsenic, chromium, copper, and lead at
levels higher than the reference sample (see Table B-10 and B-ll in Appendix B). The fillet
sample results revealed arsenic and copper at concentrations substantially greater than the
reference sample.
Benthic invertebrate samples were analyzed for nine metals (arsenic [including As+3, As+5,
and total As], cadmium, chromium, copper, mercury, nickel, lead, silver, and zinc. The
benthic organisms tested were sea cucumbers (Stichpus californianus), sea slugs (Evasterias
troschelii and Mediaster aequalis), and sand shrimp (Crangon alas kensis). Table B-12 (Appendix
B) presents the results of these tissue analyses.
As presented in Table B-12, arsenic, copper, and lead were consistently detected at levels
above background in tissue samples obtained from the Site.
5.5.4 Bioassays and Benthic Community Structures
Bioassays are acute and/ or chronic tests that measure the response of a living organism to a
test substance such as a suspected contaminant. Sediment bioassays were conducted using
samples from 62 stations across the Site, and included three different tests: amphipod,
echinoderm larvae, and polychaete growth tests. Table B-7 and B-8 in Appendix B contains
the results of these tests. The results of these tests indicate that the majority of bioassay
results exceeding SMS occur immediately off the shoreline of the former Smelter Facility.
Figure 5-12 depicts the locations of the areas where bioassay results exceeded SMS criteria.
Benthic infauna form the base of many marine food chains; therefore, their overall health, as
indicated by abundance and diversity, is a good measure of the health of the sediment
ecosystem. Impacts to benthic communities were evaluated using measures of abundance,
richness, and diversity. The sediments that suggested moderate to severe impacts (i.e.,
multiple exceedances of the state sediment biological effects criteria) occurred immediately
off the shoreline of the former Smelter. These effects included abundance and richness
depressions, diversity indices less than their reference, community structures suggestive of
impacts, and/ or species-level data suggestive of impacts. Tables B-8 and B-9 in Appendix B
summarize the biological data obtained from benthic infauna abundance studies for the Site.
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PART II SECTION 6
6 Current and Potential Future Land and Resource Uses
The Asarco Smelter terminated operations in the mid-1980s. Since that time, most of the
former the buildings and structures have been demolished as part of the remedial action for
OU 07 (Asarco Demolition; see Section 4). The Fine Ore Bins building (Figure 5-1) still exists
and is used to store demolition debris and contaminated soil until the On-Site Containment
Facility is ready to accept these materials. The Smelter property is also used to stockpile
contaminated soils excavated from OU 04 (Asarco Off-Property). These contaminated soils
are contained and protected by temporary covers. Construction activities associated with
the OU 02 remediation began in 1999 and will be substantially complete in 2003 with final
completion in 2005.
6.1 Proposed Development Plans
Proposed upland development at the Facility has been the subject of seven years of land use
planning focusing on coordinated cleanup and redevelopment. The resulting Master
Development Plan (Merrit+Pardini/Sasaki Associates, August 1997) adopted by Asarco, the
City of Tacoma, Town of Ruston, and Metropolitan Park District of Tacoma in 1997
describes the basic framework of redevelopment. The following seven fundamental
elements of the plan complement Facility cleanup:
• Development Sites. The Master Plan provides for development of seven fully served
"pad ready" development sites totaling approximately 37 acres. These sites will
accommodate commercial to light industrial development including buildings, parking,
and landscape areas, controlled by local zoning.
• Parks and Pedestrian Promenade. The Master Plan includes a publicly accessible
waterfront promenade and system of park areas connecting the existing waterfront
walkway on Ruston Way to the south with Point Defiance Park to the north. The
promenade and associated pedestrian areas will be concrete paved. The shoreline on the
Commencement Bay side of the promenade will be armored to prevent shoreline
erosion. Other park areas are to be turf and plant bed areas.
• Streets and Utilities. The Master Plan makes provision for new streets and utilities to
serve all of the development sites and parks envisioned by the plan. Asarco will
construct streets and utilities to prevailing municipal design standards.
• Ruston Promontory Park. The Master Plan includes development of a new 4-acre public
view park located on a promontory over the capped On-Site Containment Facility. The
Promontory Park will include both paved and turf areas. Steep embankment slopes on
the sides of the promontory will be treated with erosion control plantings.
• New Boat Ramp and Peninsula Park. The Master Plan includes development of new
parks on Metropolitan Park District land, including a day-use park on the breakwater
peninsula, and renovation of the boat ramp/boat launching facility near the existing
Washington State ferry dock. Park areas will consist of a combination of paved and turf
areas, with some plant beds and a few smaller park structures. Site development plans
do not call for any change in the future use or operation of the Yacht Basin.
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PART II SECTION 6
• Re-vegetated Steep Slopes. As part of site cleanup, Asarco will establish vegetative
cover on slopes facing Commencement Bay. The re-vegetation effort will meet EPA
requirements for capping steep slopes and will attempt to reestablish the appearance of
forested hillsides similar to those to the north and south of the site.
• Shoreline Restoration and Protection. Approximately 7 acres of shoreline along the
Breakwater Peninsula will be enhanced with clean natural rock riprap and "fish mix" (a
substrate that enhances juvenile salmonid habitat). The shoreline adjacent to the entire
Facility will be armored and extend to the mean higher high water (MHHW) level to
protect the upland low-permeability cap to be constructed under OU 02. A slag beach
will be excavated to create 1.2 acres of new intertidal habitat. This will produce a more
biologically enhanced and productive habitat.
In addition to the uses identified in the Master Plan, there has recently been discussion by
Asarco about the possibility of incorporating residential use into the site development plans.
At this time, EPA has not been presented with specific plans for residential use. The
appropriateness of residential uses would be subject to evaluation under the requirements
of the existing OU 02 ROD. Should residential use occur, it is not expected to affect the
remedy for marine sediments and groundwater as addressed by this ROD for OU 06.
6.2 Potential Groundwater Use
Groundwater at the Asarco Facility is not currently used for drinking water or industrial
purposes. Groundwater in the shallow and deep aquifer systems is classified as either
Class II (potable; not currently used for drinking purposes) or Class III (non-potable due to
total dissolved solids [TDS] in excess of 10,000 mg/L). In general, shallow groundwater
located within approximately 400 to 500 feet from the shoreline has TDS concentrations
greater than 10,000 mg/L and is therefore deemed Class III. Shallow groundwater in certain
areas located further than approximately 400 to 500 feet from the shoreline has TDS
concentrations less than 10,000 mg/L. However, there are no known water-bearing zones of
adequate transmissivity in the shallow aquifer system to provide dependable and
significant yield to a water production well.
Based on the monitoring wells screened in the deep aquifer, TDS concentrations in the deep
aquifer are less than 10,000 mg/L indicating Class II groundwater. The former Asarco water
production well (abandoned and sealed in 1994) was screened in the deep aquifer indicating
this water-bearing zone is adequately transmissive to yield significant quantities of water.
Based on the proposed plans listed earlier in this section, there is no reason to believe that
site development will alter the classification or potential use of groundwater in the shallow
or deep aquifer systems. Drinking water for the Asarco Facility and for the surrounding
residential and commercial areas is, and will continue to be, supplied by Tacoma Public
Utilities.
6.3 Marine Use
The Site is not commonly used for recreational harvesting of shellfish and finfish. A
recreational salmon fishery is located offshore of the northern portion of the Breakwater
Peninsula. In addition, usual and accustomed fishing for the Puyallup Tribe occurs in this
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PART II SECTION 6
area. Recreational boating services are provided by the Tacoma Yacht Club and the
Breakwater Marina. Marine sediment conditions will be preserved and restored and will
continue to provide habitat for biological resources. Present and future recreational,
commercial, and tribal fishing will continue.
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PART II SECTION 7
7 Summary of Site Risks
Baseline risk assessments were performed as part of the RIs for OUs 02 and 06 to address
both human health and ecological risks. A baseline risk assessment estimates what risks a
site poses if no actions are taken. It provides the basis for formulating and implementing an
action and identifies the contaminants and exposure pathways that need to be addressed by
the remedial action. This section of the ROD summarizes the results of the baseline risk
assessments performed for the Site. Section 7.1 summarizes the human health risk
assessment findings including risks from groundwater and seafood ingestion. Section 7.2
discusses the ecological risk assessment findings including risks to aquatic receptors from
groundwater and sediments.
7.1 Human Health Risk Assessment
Separate human heath risk assessments were performed for groundwater and marine
sediments. Potential health risks associated with all site media (including groundwater)
were addressed in a risk assessment performed for the upland portion of the Facility
(Kleinfelder, December 1992). The 1992 risk assessment was completed in accordance with
national and regional EPA risk assessment guidelines in effect at the time. The 1992 risk
assessment evaluated potential risks from exposure to contamination in soil, slag, surface
water, air, and groundwater. The findings of the 1992 risk assessment pertinent to
groundwater are summarized in Section 7.1.1.
Section 7.1.2 discusses a seafood ingestion study (Roy F. Weston, October 1996) that was
conducted as a supplement to the CB/NT RI/FS and included sediment chemical and
biological data collected by Asarco. Additional chemical and biological data from the
expanded RI/FS were also used to evaluate potential contaminant effects and associated
risks to subsistence and recreational fisherpersons who may ingest fish from the waters
adjacent to the Site.
7.1.1 Groundwater Risks
The risk assessment identified chemicals of concern (COCs) in groundwater based upon a
screening evaluation that compared the maximum concentration a chemical detected in
groundwater to a health-based concentration. The screening evaluation was based on the
frequency of detection, toxicity, persistence, and mobility of these COCs.
COCs in groundwater that potentially present risk to human health were also evaluated
under two scenarios. First, for groundwater classified as potable (i.e., Class II groundwater),
the COCs were evaluated by comparison to drinking water criteria. This resulted in the
selection of antimony, arsenic, beryllium, cadmium, chromium, copper, lead, manganese,
nickel, and silver as COCs. Second, for groundwater not suitable for drinking due to total
dissolved solids (TDS) content higher than 10,000 mg/L (i.e., Class III groundwater), the
COCs were selected for their potential to migrate into Commencement Bay and impact
humans who might consume seafood (i.e., via groundwater discharge and bioaccumulation
in marine life). Seven metals (arsenic, beryllium, copper, lead, manganese, mercury, and
zinc) were selected as COCs for the second scenario.
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PART II SECTION 7
Potential human health impacts associated with ingestion of or direct exposure to
groundwater were estimated for a hypothetical residential setting and for industrial and
commercial workers. The risk assessment results showed that estimated cancer risks and
non-cancer health effects from the Site are the highest under the residential use scenario
from drinking Site groundwater. Hypothetical residents exposed to the maximum
groundwater concentration from birth to age 30 (the reasonable maximum exposure or
RME) have total excess cancer risks on the order of lO3 to lO1 and noncarcinogenic hazards
of 8 to 1,019 depending on the area of the Site. Risks from drinking water, however, were
second to soil ingestion risks for all receptors. Drinking water was only evaluated
quantitatively at the wells where the two highest carcinogenic and noncarcinogenic risks
were located. Arsenic is responsible for virtually 100 percent of the carcinogenic risk in
groundwater with an excess cancer risk of 4 x 102, and 90 percent of the noncarcinogenic
hazard (total hazard index of 181).
Potential acute hazards from fish exposed to chronic, undiluted concentrations in
groundwater were also considered in the human health risk evaluation of groundwater.
Results of a screening comparison showed hazards to recreational fisherpersons from four
metals: arsenic, mercury, manganese, and beryllium.
Human health risks associated with dimethylaniline (N,N-dimethylaniline or DMA) and
related breakdown products (methylaniline [N-methylaniline] and aniline) were evaluated
qualitatively in the 1992 risk assessment. As stated in Section 5.4.1, DMA-related
compounds occur in Class III groundwaters at the Site. The risk assessment acknowledged
that such groundwater is not suitable as a drinking water source. However, the Class III
groundwater was considered a hypothetical drinking water pathway for purposes of
assessing risks associated with DMA and related compounds. The human health threat was
found to be low. Further, exposure and hazards to recreational fisherpersons due to the
release of DMA to Commencement Bay by the discharge of Class III groundwater from the
Facility was also found to be minimal (Kleinfelder, December 1992).
The complete human health risk assessment is presented as Appendix M of the RI report
(Hydrometrics, August 1993). A summary of the 1992 risk assessment is also presented in
Section 6 of the 1995 ROD for OU 02 (EPA, March 1995).
7.1.2 Seafood Ingestion Risks
A human health screening risk assessment was performed to address risks attributed to
consumption of fish taken from waters at and adjacent to the Site (Roy F. Weston, October
1996). It was assumed that human consumption of fish was the most likely and only route of
exposure associated with contaminated sediment and surface waters of Commencement
Bay. Only ingestion was considered because dermal contact with the sediments or
respiratory exposure to sediment vapors was considered improbable for saturated
sediments. It was also assumed that fishing for demersal resident finfish (e.g., sole, sculpin,
etc.) would be similar to the fishing opportunities and access provided at the public pier
(south of the Asarco Facility on Ruston Way). Salmon were not addressed, as these fish are
transient and mobile.
Samples of rock sole (whole body and fillets) were collected from five areas near the Asarco
shoreline as well as from one reference area near Brown's Point. Rock sole were selected
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PART II SECTION 7
because they are one of the few species that could be readily obtained at the Site and are
year-round residents within the area. All of the samples were analyzed for several metals.
The samples from Brown's Point were used to represent background conditions and assess
if concentrations of metals in the fish from the water offshore of Asarco are above
background levels. Because the sample fish catch was limited and because only one
background sample was available, this assessment was considered a screening analysis.
Tables B-10 and B-ll in Appendix B summarize the chemical concentrations detected in the
sole body and fillet tissue respectively. The inorganic arsenic level in the Brown's Point
sample (0.034 mg/kg) was less than the average of the five samples (0.056, range of 0.022 to
0.083 mg/kg) collected from the waters at and adjacent to the Site, but it was higher than
and/or comparable to the level found in two of the five individual Asarco samples (0.022
and 0.038 mg/kg). Arsenic was the only metal evaluated in the risk assessment because it
was the only contaminant detected in all of these fish samples that exceeded its respective
risk-based screening concentration developed by EPA Region III (EPA, October 1995).
For the risk assessment, cancer risks and non-cancer health impacts from inorganic arsenic
were estimated using the maximum fish concentration found in the five samples. This
maximum arsenic concentration was then used to assess the risk associated with a range of
fish ingestion rates (e.g., ingestion rates for subsistence and recreational fisherpersons). The
low end of this range (1 gram per day of fish) was selected to represent the consumption of
an infrequent sports fisherperson, who might eat fish from the waters at and adjacent to the
Site a few times a year. A high-end assumption (292 grams per day of fish over 24 years;
350 days per year) was selected to represent the consumption of a subsistence fisherperson.
The potential non-cancer health impacts were evaluated by comparing the exposures
calculated from eating fish to EPA's Reference Dose (RfD). The RfD represents an exposure
level that an individual may be exposed to without experiencing any health impacts. All of
the exposures, using the range of ingestion rates (infrequent sports fisherperson ingesting
54 grams/ day to subsistence fisherperson ingesting 292 grams/ day), were below the RfD
for both the Site and reference samples. Therefore, non-cancer health impacts from eating
finfish are considered unlikely.
The potential cancer risks estimated for the sports fisherperson from eating fish taken from
waters at or adjacent to the Site was about 6x10 6, while the potential cancer risks for the
subsistence fisherperson was estimated to be approximately 2x10 4.
A risk assessment was also done using the Brown's Point reference sample. The estimated
cancer risk for a subsistence fisherperson for this reference sample was approximately
7xl0'5. Therefore, the cancer risks from consuming fish taken from waters at or adjacent to
the Site appear to be slightly higher than that from consuming fish from the reference area.
This conclusion, however, is somewhat uncertain because of the limited sampling done in
the reference area.
7.1.3 Summary of Human Health Risk Uncertainties
Every aspect of a risk assessment contains sources of uncertainty. "Typical" risks are
calculated as a comparison to provide conservative estimates. Some of the uncertainties for
the human health risk assessments result from the following factors:
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PART II SECTION 7
• The amount and type of fishing that may occur at the Site in the future is uncertain.
• The assumption that cancer risks are higher at the Site may be a disputed conclusion
because comparable sampling data available for the reference area is limited.
• In the human health risk assessment for sediments, health-protective assumptions (e.g.,
subsistence ingestion rates, maximum fish contaminant levels) were used to estimate the
potential cancer risk and non-cancer health impacts. The impacts from consuming rock
sole from the water adjacent to the Site are believed to be conservative.
• There is a lack sample data representing additional species of finfish and other aquatic
life from near the Site that may be consumed by humans.
7.2 Ecological Risk Assessment
Ecological risk was evaluated by the Asarco Sediment/Groundwater Task Force. Sections
7.2.1 and 7.2.2 describe the associated findings for groundwater and sediments, respectively.
7.2.1 Groundwater
As addressed in Section 5.1.1, Site groundwater ultimately discharges to Commencement
Bay. Therefore, possible groundwater-related risks to aquatic life in the waters and marine
sediments of Commencement Bay were evaluated.
In 1996, the Asarco Sediment/Groundwater Task Force was formed to conduct additional
evaluations related to groundwater and its potential impact on the aquatic life in
Commencement Bay. The Task Force, consisted of personnel from EPA, Ecology, National
Oceanic and Atmospheric Administration (NOAA), and other Trustee agencies. Specifically,
the Task Force considered possible effects of metals loading to marine sediments and bay
waters under both pre- and post-remediation conditions.
The RI/FS process considered a wide range of organic compounds and metals that could
potentially affect ecological receptors. With respect to organics, the RI and post-RI
groundwater monitoring determined that, with the exception of compounds related to
DMA (e.g., aniline) present in the Southeast Plant/DMA area, organic constituents are
detected infrequently and typically at low concentrations (See Section 5 and Appendix A).
The risk assessment work conducted during the RI indicated that DMA-related compounds
do not accumulate in fish and have a negligible contribution to human health risk.
Monitoring data collected over the years since the RI indicate that the concentrations of
DMA-related compounds decrease to very low or non-detectable levels before they reach
Commencement Bay. Organic constituents are therefore not considered COCs for OU 06,
due to their isolated numbers and distribution, low concentrations near the shoreline, and
negligible risk.
Specific inorganics in groundwater have been regularly evaluated through the RI/FS
process and the post-RI groundwater monitoring program. Most recently, the Asarco
Sediment/Groundwater Task Force re-assessed the list of COCs by reevaluating the
following metals: arsenic, cadmium, copper, lead, nickel, and zinc. Based on modeling and
post-RI monitoring data, the Task Force determined that arsenic and copper represent the
primary COCs for groundwater discharging to Commencement Bay (Hydrometrics, April
1999).
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PART II SECTION 7
The findings of the Task Force regarding the impact of groundwater on the sediments and
waters of Commencement Bay are summarized as follows:
• Under current (pre-remediation) conditions, metals loading (in particular arsenic and
copper) to Commencement Bay by groundwater and surface water discharges results in
potential risks to aquatic organisms in the water column as indicated by exceedance of
applicable water quality criteria.
• Contaminants present in marine sediments at the Site are believed to be primarily
associated with historical contaminant sources other than groundwater (e.g., historical
surface water discharges and erosion and deposition of slag particles). However, the
Task Force did not attempt to quantify the importance or magnitude of these historical
contaminant sources.
7.2.2 Sediment
Based on information obtained during the Asarco Remedial Investigation (Rl), EPA
recognized that the Asarco OU 06 Site had characteristics that set it apart from other
Operable Units in the Commencement Bay/Nearshore Tideflats area. Asarco sediments are
different from most other sediments in Commencement Bay due to the presence of slag.
Slag has high concentrations of metals, but these metals are bound in a rock-like form,
which are not necessarily available to the benthic community. Therefore, the sediment
chemistry could have high concentrations, yet the biological community could be healthy.
This difference was first noted in the Commencement Bay/Nearshore Tideflats ROD (EPA,
September 1989) and later in the Upland Smelter Facility ROD (EPA, March 1995). The
difference was further addressed by the Sediment Design Group, with representatives from
EPA, Ecology, and NOAA.
Supplemental marine sampling and analyses conducted at the Asarco Sediments Site
(OU 06) in 1989 and 1990 more clearly defined the peripheral areas where biological effects
were observed (Parametrix, 1990 and 1991). An additional supplemental marine survey
determined that benthos in the Yacht Basin were exhibiting toxic effects; however, it could
not be determined what caused these effects. EPA produced a Supplemental Feasibility
Study (SFS) that was based on this previously collected data (Roy F. Weston, October 1993).
To further define the areas and types of chemicals associated with potential contaminant
effects, EPA, Asarco, and agencies participating in the Asarco Sediment/Groundwater Task
Force agreed that an expanded RI/FS should be conducted. The chemical and biological
data used to complete the SFS and the Expanded RI/FS investigations were obtained from
62 sampling stations in the offshore area (Figure 5-10). EPA used the data from these 62
sampling stations to characterize potential ecological risks as presented in the Ecological Risk
Assessment and Seafood Consumption Screening Risk Assessment (Roy F. Weston, October 1996).
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PART II SECTION 7
All of the data and evaluation measures were correlated and used in a "preponderance-of-
evidence" approach to more fully identify current and potential impacts and risks to aquatic
receptors. Because of the presence of slag, the bulk sediment chemistry results may not be
representative of the actual toxicity of the sediments. Based on this difference between
sediments at the Asarco Sediments Site and most other sediments in Commencement Bay,
the Sediment Design Group relied upon best professional judgement, and gave greater
weight to the benthic evaluation than to the chemistry and bioassay data. Table C-l in
Appendix C presents a summary of the chemical and biological factors that were used to
define potential ecological risk. This was accomplished by developing a range of possible
impacts that were based in part upon state SMS biological and chemical criteria. A total of
five impact categories were assigned to the Site. The locations of these five categories are
plotted by sediment station in Figure 7-1. The relative locations of the categories at the Site
were then assembled into three zones called Impact Stations, which are described as follows:
• Non-Impacted/Minimally Impacted Stations. Approximately 61 percent of the stations
are within the non-impacted/minimally impacted stations (Figure 7-1). The non-
impacted and minimally impacted stations fall into three subcategories:
Stations that are considered to be currently unimpacted and pose no potential future
risks to the aquatic organisms (e.g., fish and other bottom-dwelling animals) because
contaminant concentrations were below state SQS.
Stations that are considered to have no current impacts, but may have impacts in the
future (i.e., these stations have chemical concentrations greater than state standards
but biological testing showed no adverse impacts).
Stations that have a current minimal impact and may have impacts in the future (i.e.,
these stations had minor biological CSL exceedances, but no chemical CSL
exceedances).
• Moderately Impacted Stations. Moderately impacted stations are those that have a
limited number of adverse biological impacts (i.e., a bioassay result indicated an impact
of benthic abundance in a sediment sample that was significantly different from a
reference sample), but the overall health of the biological community does not appear to
be substantially impacted. For example, there were stations that had chemical and
bioassay exceedances above corresponding SMS criteria, but a healthy biological
community. These stations included approximately 28 percent of the locations sampled
(Figure 7-1).
• Severely Impacted Stations. Stations were considered severely impacted when
sediment chemical concentrations exceeded CSLs and multiple biological impacts (e.g.,
more than one biological test exhibited a significant effect) were observed. In addition,
every station that had a benthic community structure that indicated a stressed
environment was included in this category. Approximately 11 percent of the stations
(170,000 square yards or approximately 35 acres) exhibited these characteristics. The
severely impacted stations are shown in Figure 7-1.
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PART II SECTION 7
7.2.3 Summary of Ecological Risk Uncertainties
As mentioned previously, every aspect of a risk assessment contains sources of uncertainty.
The uncertainties associated with the ecological risk assessment are summarized as follows:
• The chemical analytical laboratory detection limits differed over time.
• The bioassay laboratory sample handling methods and testing procedures differed over
time.
• Ample benthic data from site investigations are not available.
• Sample results were assumed to represent conditions over larger areas than the samples
that were collected.
• The benthic community was assumed to be continuously exposed to a prescribed level
of contaminants, even though there is variability in contaminant distribution at the Site.
• Bioassays, since they are performed in a laboratory, do not necessarily represent Site
conditions.
• There were small variations observed between the reference area conditions and Site
conditions.
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PART II SECTION 8
8 Remedial Action Objectives
The groundwater and sediment investigations for OU 06 have identified contamination
from the release of hazardous substances to the environment that may present an imminent
and substantial endangerment to public health, welfare or the environment. The need for
action was determined based on the results of the human health and ecological risk
assessments. In addition, contaminant levels in groundwater exceed Washington State's
Model Toxics Control Act (MTCA) standards and marine water SQSs and marine sediments
are contaminated at levels above the state SMS. The remedial action objectives (RAOs) for
OU 06 are presented below.
8.1 Groundwater
EPA's RAOs for groundwater are as follows:
• Prevent ingestion of groundwater containing contaminant concentrations above federal
maximum contaminant levels (MCLs) or above risk-based goals for those substances for
which MCLs have not been established and prevent direct contact with groundwater
containing contaminant concentrations above applicable risk-based goals.
• Prevent discharge to Commencement Bay of groundwater containing contaminants at
concentrations exceeding applicable marine surface water quality standards, risk-based
levels protective of human health, or background concentrations (if background
concentrations are higher than the applicable standards).
The RAOs for groundwater are based on the intended site development uses described in
Section 6 and consistent with applicable or relevant and appropriate requirements (ARARs)
described in Section 13.
The first RAO for groundwater protects human health by limiting groundwater ingestion
and contact. In particular, the RAO addresses the potential risk associated with human
exposure to arsenic, the primary human health risk driver identified in the risk assessment
(Section 7.1).
The second RAO protects marine life in Commencement Bay by limiting contaminants in
groundwater such that marine chronic criteria are not exceeded at the point of groundwater
discharge to marine waters. In addition, risk to human health through the fish consumption
pathway is addressed by limiting the concentration of contaminants available to marine
organisms.
Specific groundwater cleanup levels protective of human health and the environment are
discussed in Section 12.
8.2 Sediment
EPA's RAO for sediment is as follows:
• Restore and preserve aquatic habitats by limiting and/ or preventing the exposure of
environmental receptors to sediments with contaminants above Washington State SMS
(WAC 173-204).
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PART II SECTION 8
The RAO for sediment is based upon predicted offshore uses as described in Section 6 and is
consistent with ARARs (see Section 13).
The RAO protects human health by restricting and limiting contaminant concentrations
available to marine biological resources that could be a source of seafood for recreational
and subsistence users.
The RAO protects marine life in the sediments of Commencement Bay by limiting exposure
to contaminated sediments by capping and dredging and by inhibiting discharge of
contaminated groundwater to the bay.
Sediment cleanup levels that are protective of human health and the environment are
discussed in Section 12.
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PART II SECTION 9
9 Description of Alternatives
The various feasibility study documents prepared by Asarco and EPA identify a range of
alternatives to address the Sediments/Groundwater OU 06. These alternatives include
active cleanup options (e.g., capping and dredging) and institutional controls (e.g., limiting
access).
An Operation, Maintenance, and Monitoring Plan (OMMP) is necessary to ensure the
continued effectiveness of any remedy. Important components of the OMMP include
maintaining the integrity of the remedy and monitoring the sediments to verify they are
meeting the RAOs. Expectations for this long-term monitoring program are summarized in
Section 12 of this document; a detailed OMMP will be prepared in parallel with the remedial
design/ remedial action (RD/RA) process, with a final long-term monitoring program in
place by the time the remedial action is complete.
9.1 Groundwater
The groundwater alternatives discussed in this section were originally presented in the
Asarco Plant Feasibility Study for OU 02 (Hydrometrics, August 1993). The alternatives
addressed in the 1993 FS were reviewed again in 2000 in light of groundwater information
that has become available in the intervening seven years (see Historical Summary of the
Evaluation of Groundwater Remedial Alternatives; Hydrometrics, June 2000). Certain elements
of the groundwater alternatives presented here are actually part of the Selected Remedy
identified in the 1995 ROD for OU 02 (EPA, March 1995). For example, contaminant source
removal, surface water controls, and site capping are part of the Selected Remedy for OU 02.
Although these remedy elements are required to meet the RAOs for OU 02, they also
directly benefit the OU 06 groundwater present immediately beneath OU 02. Specifically,
these OU 02 remedy elements will minimize transfer of contaminants from source materials
to groundwater and reduce the contaminant load discharged to Commencement Bay
through groundwater. See Section 4 of this ROD for more information on the relationship
between the four OUs associated with the Asarco Facility, including the close relationship
between OUs 02 and 06.
Table 9-1 presents four remedial action alternatives identified for OU 06 groundwater. As
discussed above, this list is based on alternatives that were first identified in the 1993 FS and
later refined in the Historical Summary of the Evaluation of Groundwater Remedial Alternatives
(Hydrometrics, June 2000).
9.2 Sediment
In evaluating cleanup action alternatives, the EPA relied on the SMS that considers net
environmental impacts, technical feasibility, and cost (WAC 173-204-570(4)). Based on the
unique nature of slag (i.e., metal contamination not necessarily available to the biological
community), and as the benthic community is a good measure of the health of the sediment
ecosystem, the benthic results were used to identify the most highly impacted areas where
remedial action is necessary. The severely impacted sediment stations (Figure 7-1) are
identified as the "Contaminant Effects Area" (Figure 9-1). Active remediation is necessary in
the Contaminant Effects Area.
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PART II SECTION 9
The presence of relatively healthy benthic communities in areas outside of the Contaminant
Effects Area suggests that active cleanup outside of the Contaminant Effects Area may not
be appropriate. Active cleanup might result in greater net negative impacts through
destruction of existing habitats than if not remediated. The moderately impacted sediment
stations (Figure 7-1) are identified as the "Moderate Impact Area" (Figure 9-1) and will not
receive active remediation. Monitoring is deemed the most appropriate action for the
Moderate Impact Area.
Five general remedial action alternatives were considered for the marine sediments in the
Contaminant Effects Area. These were:
• No action —No action is taken.
• Natural Attenuation — Reliance on natural deposition of clean sediment over time to
cover the contaminated sediment.
• Capping—Covering contaminated sediments with clean material to prevent exposure of
humans and marine organisms to contaminants.
• Dredging and Nearshore Confinement—Dredging of contaminated sediment and
placement of spoils in a nearshore confined aquatic disposal (CAD) facility.
• Dredging and Upland Disposal — Dredging of contaminated sediment and placement of
spoils under the low-permeability upland cap being constructed as part of the remedial
action for OU 02.
The Contaminant Effects Area was divided into different remediation areas (Nearshore/
Offshore, Yacht Basin, Northshore, and the Breakwater Peninsula), as shown in Figure 9-2.
The areas were identified based on the specific characteristics of each remediation area and
the potential ability to implement sediment cleanup technologies in those areas. The
alternatives considered for the Nearshore/Offshore, Yacht Basin, and Northshore areas are
summarized in Tables 9-2 through 9-4. The following discusses the remedial action
alternatives that are not suitable for a particular remediation area, including the
impracticability of remediating sediments offshore of the Breakwater Peninsula.
9.2.1 Nearshore/Offshore and Northshore Area
All five cleanup technologies listed above are considered possible in the
Nearshore/Offshore and Northshore areas (Tables 9-2 and 9-4).
9.2.2 Yacht Basin
Due to navigation concerns, capping was not considered possible for the Yacht Basin
(Table 9-3) because a sediment cap would decrease the depth of the waters and potentially
interfere with marine navigation.
9.2.3 Breakwater Peninsula
The Breakwater Peninsula area comprises the sediments east of the Breakwater Peninsula
(Figure 9-2), which is approximately 85,000 square yards or 17.5 acres. The sediment depth
off the Breakwater Peninsula in some areas is almost 100 feet deep (within 200 feet from
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PART II SECTION 9
shore). The subtidal slope in this area can be up to 50 percent. The stability of a cap on such
steep slopes is questionable, and the construction of a nearshore facility on such a slope
would be very difficult (e.g., making a berm stable on a steep slope is difficult). In addition,
dredging is not possible because the entire peninsula would need to be removed to provide
a post-dredging slope that is flat enough to be stable. Although capping or dredging of the
Breakwater Peninsula is not feasible, shoreline armoring will be placed in the intertidal
areas where possible, as part of the OU 02 remedy. This will greatly reduce the erosion of
slag in this high-energy area.
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PART II SECTION 10
10 Summary of Comparative Analysis of Alternatives
Nine criteria have been used to evaluate the different remediation alternatives individually
and against each other in order to select a cleanup remedy. A selected remedy must meet
the first two "threshold" criteria. EPA uses the next five criteria as "balancing" criteria for
comparing alternatives and selecting a preferred remedy, which is presented in the
Proposed Plan. After public comment on the Proposed Plan, EPA may alter its preference on
the basis of the last two "modifying" criteria.
The nine criteria are summarized below.
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 Applicable or Relevant and Appropriate Requirements
(ARARs). Does the alternative meet all ARARs from state and federal laws? Does the
alternative qualify for an ARAR waiver?
Balancing Criteria
3. Long-Term Effectiveness and Permanence. How well does the alternative protect
human health and the environment after completion of cleanup? What, if any, risks
will remain at the Site?
4. Reduction of Toxicity, Mobility, or Volume Through Treatment. Does the
alternative effectively treat the contamination to significantly reduce the toxicity,
mobility, and volume of the hazardous substance?
5. Short-Term Effectiveness. Are there potential adverse effects to either human health
or the environment during construction or implementation of the alternative? How
fast does the alternative reach the cleanup levels?
6. Implementability. Is the alternative both technically and administratively feasible?
Has the technology been used successfully on other similar sites?
7. Cost. What are the estimated costs of the alternatives?
Modifying Criteria
8. State/Tribal Acceptance. What are the state's and tribes' comments or concerns
about the alternatives considered and about EPA's Preferred Alternative? Do the
state and tribes 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?
The remainder of this section addresses the remediation alternatives listed in Section 9 in the
context of the nine criteria.
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PART II SECTION 10
10.1 Overall Protection of Human Health and the Environment
10.1.1 Groundwater
All of the groundwater alternatives, except the no action alternative, are protective of
human health. Institutional controls will prohibit the use of contaminated groundwater at
the Facility. The groundwater discharging to Commencement Bay may exceed the National
Toxics Rule (NTR) for fish consumption (0.14 (ig/L for arsenic). However, a risk assessment
based on data from fish tissue samples collected during the sediment RI indicates slightly
higher risks from Site contaminants to people consuming large quantities of fish from the
Site as compared to the Reference site. This risk assessment information is based on pre-
remediation conditions where groundwater samples collected from wells adjacent to the
shoreline indicate arsenic at concentrations of approximately 10 to 30 (ig/L. Thus, any
human health risk is expected to decline further after remediation is complete. In addition,
contaminant concentrations at OU 06 are expected to be reduced by the cleanup activities.
The remedial alternatives involving active groundwater treatment would likely be more
protective than capping and groundwater interception (where groundwater is
pumped/treated or treated in situ) since groundwater contaminant levels will be further
reduced. The no-action alternative is not protective of human health and thus is not
evaluated further.
At present, the quality of groundwater discharging to Commencement Bay is not
considered protective of the environment. Specifically groundwater discharging to the Bay
contains metals (primarily copper) in excess of their respective marine chronic criteria.
Therefore, the no action alternative is not considered protective. Alternative GW-C
(Pump/Treat and Discharge to Outfalls) would likely reduce metal loading to the Bay to
acceptable levels with properly located extraction wells. Alternatives GW-D (In situ
Groundwater Treatment) and GW-E (In situ Treatment by Seawater Injection) are best suited
to precipitate arsenic by oxidation. However, these alternatives may not effectively reduce
copper concentrations because copper becomes more mobile as oxygen levels increase.
Alternative GW-B, the Preferred Remedy identified in the Proposed Plan (EPA, January
2000a) is believed to have the greatest likelihood of reducing metals loading to
Commencement Bay by minimizing groundwater discharge by an estimated 75 to
95 percent.
10.1.2 Sediment
Protectiveness is based on how clean the remaining surface sediments will be following
cleanup. The assumption that lower contaminant concentrations result in higher sediment
quality was primarily used to rank the alternatives for overall protection. All of the
sediment alternatives, including the No Action alternative, are believed to be protective of
human health based on a screening risk analysis (see Section 7.1.2) performed for the Site.
The No Action alternative is not protective of the environment and is therefore not further
evaluated under the nine criteria. Capping and dredging, however, are expected to achieve
EPA's and Ecology's acceptable risk criteria.
Natural Recovery. Natural Recovery was evaluated as part of the RI/FS (Parametrix,
December 1996). Evaluations determined that recovery of the sediments to concentrations
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PART II SECTION 10
lower than the cleanup levels would not occur within a reasonable time frame as defined by
the SMS (i.e., less than 10 years). Natural Recovery cannot occur within a reasonable time
frame because there is not sufficient sedimentation in this area to cover existing
contaminated sediment within the 10-year time frame. The Natural Recovery alternatives
(S-l B, S-2B, and S-3B [Tables 9-2, 9-3, and 9-4]) are not considered protective of the
environment because they would not prevent aquatic organisms from coming into contact
with the contaminants for many years, if ever. Therefore, the natural recovery alternatives
are not evaluated further under the nine criteria.
Capping Versus Dredging. Capping is the most protective alternative in the Nearshore area,
where the depth of contamination is very deep because the shoreline is constructed of slag.
Dredging of this area would be difficult due to concerns regarding the stability of subtidal
slopes. Furthermore, dredging would inevitably encounter and expose the slag that is
impracticable to remove in its entirety. Therefore, the highest degree of protectiveness
would be provided by capping the contaminated sediments in the Nearshore, Offshore, and
Northshore areas with clean sediment imported from another location (note that the
Northshore area may be dredged depending on remedial design considerations).
10.2 Compliance with Federal and State Environmental Standards
10.2.1 Groundwater
Modeling performed by the Task Force indicates that state and federal laws applicable to
protection of marine water quality may not be currently achieved in Commencement Bay
waters within a few feet of the shoreline for all metals (Hydrometrics, April 1999). Although
model results did indicate some metal concentrations above marine chronic criteria, the
Task Force placed more emphasis on empirical data rather than model predictions in
assessing current and potential impacts from groundwater discharge. The Task Force
concluded that with the exception of copper, groundwater discharge currently does not
cause metal concentrations to be higher than marine chronic criteria. Under the Alternative
GW-B, metals concentrations in groundwater flowing toward the shoreline are expected to
decrease in future years in response to the site-wide changes (i.e., reduced groundwater
discharge) affected by the cleanup. These changes are expected to allow all groundwater
ARARs to be met in the future.
Alternative GW-C (Pump/Treat and Discharge to Outfalls) is likely capable of achieving
ARARs at the point of compliance with properly located extraction wells. It is not certain if
Alternatives GW-D and GW-E (In situ Treatment by Seawater Injection and Pump/Treat
and Discharge to Outfalls, respectively) would achieve groundwater ARARs. The Task
Force findings suggest that these two alternatives could actually increase the copper loading
to Commencement Bay by raising redox conditions in the groundwater system (the mobility
of copper increases with the dissolved oxygen content).
10.2.2 Sediment
For sediments, the RAO is to restore and preserve aquatic habitats by limiting and/ or
preventing the exposure of environmental receptors to sediments with contaminants above
Washington State SMS. An isolating cap would achieve the standards, as long as it stayed in
place as a physical barrier and does not become recontaminated. Institutional controls
would help ensure that the integrity of the cap is maintained. The dredging/nearshore
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PART II SECTION 10
confinement and dredging/upland disposal alternatives would also meet the standards if
all of the contaminated sediments could be removed. Dredging in the Nearshore/ Offshore
area would be less likely to meet ARARs than dredging in the Yacht Basin, since removing
all of the contaminated material in this area would be impossible.
The Clean Water Act Section 404 criteria will be met, including any potential need for
mitigation and related Endangered Species Act requirements. This is being addressed as
part of the Clean Water Act Section 404 analysis and will be completed concurrently with
this ROD.
10.3 Long-Term Effectiveness and Permanence
10.3.1 Groundwater
All of the alternatives will minimize generation of contaminated groundwater by reducing
groundwater recharge, flow through contaminated source areas, and ultimately the
discharge of contaminants to Commencement Bay. The remedial alternatives involving
active groundwater treatment would further lower groundwater contaminant
concentrations and, therefore, have the lowest residual risk. However, this benefit is not
permanent, as it would occur only as long as the treatment systems were operating. Since
most of the onsite slag will not be removed by any of the upland cleanup activities, the slag
will continue to contribute contaminants to groundwater indefinitely. Therefore, reduction
of surface water infiltration and groundwater flow to Commencement Bay is critical to
making the Selected Remedy effective as a long-term protection of human health and
environment. The in situ groundwater treatment and seawater injection alternatives may be
less reliable than the pump and treat alternative because these treatment technologies are
generally less proven. These latter treatment methods may not be necessary if effectiveness
can be achieved with groundwater and surface water flow reductions combined with
selected contaminant source removals.
10.3.2 Sediment
Removing contaminated sediment and consolidating it upland is considered more reliable
than capping in place because removal and placement results in a smaller and more
controlled area of contaminated sediments. In addition, an engineered upland disposal
facility is easier to inspect, monitor, and maintain than a larger aquatic capped area or
aquatic disposal site. Therefore, the greatest degree of long-term effectiveness is provided
by dredging the contaminated sediments (assuming all contamination can be removed) and
placing them on the upland Facility. In those areas where all contaminated material cannot
be removed (i.e., the Nearshore area), in situ capping is best. In these areas, a cap can be
designed with appropriately sized material such that it provides long-term isolation of the
contamination (i.e., it remains in place and does not wash away with wave action or ship
traffic and does not become recontaminated), while providing acceptable aquatic habitat.
The cap would also be monitored regularly to ensure it is being effective.
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PART II SECTION 10
10.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
10.4.1 Groundwater
All of the groundwater alternatives, including GW-B, would reduce the toxicity, mobility,
and volume of contaminants through treatment. Groundwater intercepted at the On-Site
Containment Facility and Stack Hill will be routed through the surface water treatment
system, as required, before being discharged to Commencement Bay. The in situ treatment
and seawater injection treatment alternatives would promote chemical precipitation of
arsenic from groundwater, thereby reducing the arsenic load reaching Commencement Bay.
Because all alternatives include capping, groundwater interception, and replacement of
leaking subsurface water lines, the mobility of the contaminants and volume discharged to
Commencement Bay is expected to be reduced by an estimated 75 to 95 percent.
10.4.2 Sediment
None of the alternatives involve treatment of the sediments. Treatment is not proposed for
the sediments for several reasons. First, in order to treat the sediments, they must be
removed. This is difficult in the Nearshore/Offshore area of OU 06 since the contaminated
sediments are located in waters up to approximately 150 feet deep. Therefore, the chance of
leaving contamination behind is very high. Second, since slag was poured to create the
shoreline in portions of the Nearshore area, dredging in this area would be difficult due to
slope stability issues. Third, the net benefit of treating the sediments is questionable as slag
particles within the sediment matrix are already in a relatively immobile form (e.g., the slag
does not tend to be bioavailable). Fourth, costs associated with treatment of the Yacht Basin
sediments prior to upland containment above the groundwater table and under a low-
permeability cap would be disproportionate to the incremental benefit that may be achieved
if the sediments were contained under an upland cap without treatment.
10.5 Short-Term Effectiveness
10.5.1 Groundwater
All of the alternatives present minimal risks to the community and workers during cleanup.
Similarly, all of the alternatives have minimal short-term environmental impacts. Best
Management Practices (BMPs) would need to be implemented during construction for all
alternatives. To limit the short-term impacts, implementation of any of the groundwater
alternatives must be coordinated with the other upland cleanup actions. All of the
alternatives therefore would require several years to construct, and several years are
expected for there to be a noticeable improvement in groundwater quality.
10.5.2 Sediment
Short-term environmental impacts include water quality impacts, exposure of marine life to
contaminants, and habitat loss (i.e., fisheries impacts) during the implementation of the
remedial alternative. Remedial alternatives that involve dredging contaminated sediments
would result in a potential for deleterious water quality and fisheries impacts (due to
disturbance of contaminated sediment), human exposure to contaminants, and possible
worker injury/exposure resulting from the use of dredging equipment. Remedial
alternatives that involve capping contaminated sediments and constructing a confined
aquatic disposal area would result in short-term loss of aquatic habitat due to covering the
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PART II SECTION 10
currently existing benthic community. These alternatives also have a potential to suspend
contaminated sediment. Overall, capping has the greatest short-term effectiveness (e.g., the
least short-term impact) because it requires the least amount of in-water work, and the
contaminated material is not significantly disturbed. Dredging and construction of a
nearshore facility would have the greatest short-term impacts due to the extensive in-water
work required.
Although all these alternatives have short-term impacts, much of the short-term risk
associated with both dredging and capping can be significantly reduced by carefully
choosing methodology and BMPs (e.g., controlling the dredge depth and speed of dredging,
controlling the rate of placement of cap material).
10.6 Implementability
10.6.1 Groundwater
Compared to the others, the Alternative GW-B is most easily implemented. The pump and
treat alternative would be the most difficult to construct and operate since very large
quantities of groundwater would require pumping and treatment (i.e., it is estimated that
hundreds of gallons per minute would be required due to the incidental capture of seawater
by the extraction system). However, pump and treat technology is reliable and available.
The remedial alternatives involving in situ groundwater treatment would be easier to
construct and operate but are less proven and reliable technologies than pump and treat.
The in situ treatment alternatives would require pilot testing to confirm their efficacy at the
Site. All of the alternatives would require long-term operation, maintenance, and
monitoring.
10.6.2 Sediment
Capping and dredging are feasible actions depending on site-specific conditions.
Construction of a sediment cap in the Nearshore/Offshore area would occur in relatively
shallow water with modest subtidal slopes. The results of the pilot cap study (Parametrix,
February 2000) indicate that capping in this area can be accomplished without unusual
difficulty. Similar conditions exist in the Northshore area and placement of a sediment cap
in that area is also considered feasible.
Dredging is infeasible in the Nearshore/Offshore area for several reasons. First, when the
slag was poured, it solidified vertically in some areas, such that sediment removal in these
areas could destabilize the bank (i.e., undercut some upland portions of the Facility).
Second, if all slag were removed, a cutback of 60 to 120 feet of material would be required,
making removal of the entire Breakwater Peninsula necessary. Due to the slag depth of the
Breakwater Peninsula (up to 125 feet), removal of this entire peninsula is not considered a
viable option. The Yacht Club facilities and parking lot located on the Breakwater Peninsula
also prohibit dredging of the Nearshore/Offshore area. Placement of a sediment cap in the
area offshore of the Breakwater Peninsula is also impracticable for reasons discussed in
Section 9.2.3.
The Yacht Basin has relatively shallow water and gentle subtidal slopes such that dredging
in this area can be accomplished. However, the presence of piers and pilings may slow the
work and require the use of hand operated suction dredge equipment. A nearshore confined
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PART II SECTION 10
aquatic disposal (CAD) facility is also feasible but would require more engineering controls.
Confined upland disposal of sediment at OU 02 would be more easily implemented than the
nearshore confinement alternative because the upland work is already underway and space
has been made available under the OU 02 low-permeability soil cap.
10.7 Cost
Cost estimates presented in this ROD are intended to be accurate within a range of +50 to
-30 percent. Cost estimates are provided in Tables 9-1 through 9-4.
10.7.1 Groundwater
Aside from the no action alternative (GW-A), Alternative GW-B is the least costly
($1.8 million). The in situ groundwater treatment alternatives (GW-D and GW-E) are similar
in cost ($4.3 million and $4.4 million, respectively). The pump and treat alternative (GW-C)
is most expensive ($37.8 million).
Note that additional groundwater interception at the upgradient end of the Facility
(southeast of Cooling Pond and Southeast Plant Area, see Figure 5-1) is technically possible
under Alternative GW-B. However, Asarco has demonstrated that intercepting additional
groundwater at the southwest (uphill) side of the Facility could only be done at a cost that is
disproportionately high compared to the limited incremental environmental benefit
expected.
10.7.2 Sediment
Nearshore/Offshore Area. For the Nearshore/Offshore area, dredging with upland disposal
(Alternative S-1E) is the most expensive alternative at $26.2 million. Capping (Alternative
S-1C, $11.6 million) is slightly less costly than dredging with nearshore confinement in a
CAD (Alternative S-1D, $12.8 million).
Northshore Area. For the Northshore area, dredging with nearshore confinement in a CAD
(Alternative S-3D) is the most expensive alternative at $0.86 million. Dredging with upland
disposal (Alternative S-3E, $0.70 million) is slightly less costly than capping (Alternative
S-3C, $0.74 million).
Yacht Basin. For the Yacht Basin, dredging with upland disposal (Alternative S-2D,
$3.6 million) is less costly than dredging with nearshore confinement in a CAD
(Alternative S-2C, $5.1 million).
10.8 State/Tribal Acceptance
Ecology staff have reviewed this ROD with respect to governing state statutes and
regulations administered by Ecology. Ecology concurs with the Selected Remedy as
identified in this ROD.
The Native American tribes have participated in the review of certain major Site documents.
No tribal comments were received on the Proposed Plan. It is EPA's assumption that tribal
representatives are in general agreement with the Preferred Remedy identified in the
Proposed Plan.
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PART II SECTION 10
10.9 Community Acceptance
EPA received written or verbal comments on the Proposed Plan from a few individuals and
from Citizens for a Healthy Bay (see Part 3, Responsiveness Summary). The comments did
not identify any issues causing EPA to change the core elements of the Preferred Remedy as
presented in the Proposed Plan. Other comments were received from state and federal
agencies. All comments, with EPA responses, are presented in Part 3 of this ROD. Based on
the number and nature of comments received, EPA believes that the Preferred Remedy as
identified in the Proposed Plan is acceptable to the public.
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PART II SECTION 11
11 Principal Threat Waste
The NCP establishes an expectation that EPA will use treatment to address the principal
threats posed by a site wherever practicable (NCP Section 300.430(a)(l)(iii)(A)). Principal
threat wastes include wastes with high concentrations of toxic compounds or wastes that
are highly mobile and generally cannot be contained in a reliable manner or would present a
significant risk to human health and the environment should exposure occur (EPA, July
1999).
For groundwater and marine sediment at OU 06, the principal threat wastes are the
contaminated materials in the six OU 02 source areas, which are identified in Section 5 and
Figure 5-1 (the groundwater and sediment themselves are not considered principal threat
wastes). The OU 02 source areas are:
• Stack Hill
• Copper Refinery
• Cooling Pond
• Fine Ore Bins Building
• Arsenic Kitchen
• Southeast Plant Area
The principal threat wastes at the Site are addressed by the OU 02 ROD (EPA, March 1995).
These materials are being excavated and removed from the subsurface where practicable
and placed in the On-site Contaminant Facility as part of the ongoing remedial action for
OU 02.
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PART II SECTION 12
12 Selected Remedy
The Selected Remedy for OU 06 includes the implementation of the following four
alternatives:
• Groundwater Alternative GW-B. Source removal, soil capping and surface water
controls, groundwater interception/treatment, replacement of leaking subsurface water
lines, and institutional controls and monitoring (see Table 9-1). Note that the majority of
the remedy elements associated with Alternative GW-B are being addressed by the
requirements of the OU 02 ROD (EPA, March 1995). With the exception of stipulating
institutional controls and long-term monitoring related to groundwater, this ROD is not
requiring additional groundwater remedies over and above those already being
implemented under the OU 02 remedial action (see Section 4 for additional information
on the relationship between OUs 02 and 06). This ROD also establishes the groundwater
RAOs, and identifies the cleanup levels, point of compliance, and long-term monitoring
requirements for groundwater.
• Sediments Remedy S-1C for Nearshore/Offshore Area. Sediment capping (Table 9-2).
• Sediments Remedy S-2D for Yacht Basin. Dredging and upland disposal (Table 9-3).
• Sediments Remedy S-3C for Northshore Area. Sediment capping (Table 9-4). Although
capping is currently the Selected Remedy, dredging will be reevaluated for the
Northshore area during the remedial design as described in Section 12.2.
The estimated cost of the Selected Remedy is $19.2 million. The estimated $19.2 million cost
is divided between groundwater and marine sediment remedies as follows:
Institutional Controls and Long-Term Monitoring
Components of Groundwater Remedy (Alternative GW-B) $1.8 million
Sediments Remedy, Nearshore/Offshore Area (Alternative S-1C) $11.6 million
Sediments Remedy, Yacht Basin (Alternative S-2D) $5.1 million
Sediments Remedy, Northshore Area (Alternative S-3C) $0.7 million
Total $19.2 million
The details of the selected remedies are described below for groundwater (Section 12.1) and
marine sediments (Section 12.2).
12.1 Groundwater
EPA's Selected Remedy for groundwater is Alternative GW-B. Alternative GW-B includes
elements currently being implemented under the OU 02 ROD (EPA, March 1995) plus long-
term monitoring and institutional control requirements addressed in this ROD. Together,
these remedy elements comprise EPA's Selected Remedy for OU 06. This remedy is being
selected because evaluations conducted by the Asarco Sediment/Groundwater Task Force
indicate that marine sediments and the waters of Commencement Bay will be protected by
the remedial actions being implemented under the OU 02 cleanup. Combined with long-
term monitoring and institutional controls being added by this ROD, the groundwater
remedy is expected to be permanent and to meet the RAOs.
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PART II SECTION 12
12.1.1 OU 02 Groundwater Remedy Elements
The OU 02 remedy is in progress with substantial completion scheduled for 2003 and final
completion expected in 2005. The OU 02 remedy elements applicable to groundwater and
included in Alternative GW-B are source excavation and placement in the On-site
Containment Facility, site capping and surface water controls, groundwater interception/
treatment, and removal of leaking underground piping. Source control measures will
reduce the volume of contaminants that are transferred to the groundwater. Capping,
surface water controls, groundwater interception, and removal of leaking pipes is expected
to reduce groundwater discharge to Commencement Bay by approximately 75 to 95 percent
(Hydrometrics, June 2000).
Source Removal. Excavation of principal threat wastes and contaminated soils from the
OU 02 Site and permanent disposal of these materials in an On-site Containment Facility.
Source control also includes stabilization of the shoreline to reduce slag erosion and its
transport to the waters and sediments of Commencement Bay.
Site Capping and Surface Water Controls. The OU 02 Site (including the Breakwater
Peninsula) will be capped with a low-permeability soil cover system to inhibit infiltration of
surface water and precipitation. Run-off from precipitation falling on the cap will be
captured in onsite surface water drainage systems and discharged to Commencement Bay.
The cap surface will include controls to capture and direct surface water to Commencement
Bay. Currently, a large percentage of groundwater discharging to Commencement Bay
originates from onsite recharge of precipitation and surface water run-on. As part of the
remedial action for OU 02, surface water controls will be constructed to capture surface
water that would otherwise run onto the Facility from uphill locations and infiltrate into the
shallow aquifer system. The captured surface water will be treated as necessary to meet the
requirements of the OU 02 ROD (EPA, March 1995), and discharged to Commencement Bay.
Groundwater Interception/Treatment. Subsurface trenches or drains will be installed
upgradient of the proposed On-site Containment Facility and railroad tunnel. These
subsurface drainage systems will intercept and capture groundwater that would otherwise
enter Facility aquifers. By reducing the recharge of Site groundwater, the overall
contaminant load transported to Commencement Bay will be reduced. Groundwater
captured by the interception trenches and drains will be directed to the Facility's surface
water collection system and treated in conjunction with surface water collected as part of
operations and maintenance requirements for OU 02. Treatment of the captured
groundwater will be subject to the water quality requirements for OU 02 waters being
discharged to Commencement Bay.1
Removal of Leaking Underground Piping. Leakage from underground stormwater, sewer,
water, and fire protection lines is believed to contribute a significant volume of recharge to
the shallow aquifer system. These underground lines will be either abandoned (sealed) or
removed and replaced with new piping as needed. Some of this work has already been
1 The design of this OU 02 water treatment system is in progress. Both polymer- and filtration-based systems designed to
remove suspended metals from water are being evaluated. The post-treatment quality of the stormwater will not be determined
until ongoing engineering studies are complete. However, design criteria call for the water to meet water quality criteria at the
boundary of a defined mixing zone in Commencement Bay.
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PART II SECTION 12
completed. Reduction of groundwater recharge from leaking pipes will reduce the overall
contaminant load associated with groundwater discharging to Commencement Bay.
12.1.2 Additional Groundwater Remedy Elements
The Selected Remedy includes two elements not previously addressed in the OU 02 ROD
(EPA, March 1995). These remedies are institutional controls and long-term, post-remedial
action monitoring.
Institutional Controls. Institutional controls for groundwater will include restrictions on
groundwater use for domestic or industrial purposes. The objective of the prohibition is to
prevent human exposure to contaminated groundwater. This will be achieved by
prohibiting the drilling of water wells (other than for environmental monitoring or
treatment) and prohibiting the use of groundwater as a drinking water source. Specifically,
no water wells will be permitted in the shallow and deep aquifer systems. The prohibition
on groundwater use is expected to be in force into perpetuity for shallow groundwater
(slag, marine sand, and intermediate aquifers) because source materials (e.g., slag) will
remain in place and in contact with shallow groundwater, under the terms of the OU 02
ROD (EPA, March 1995). Therefore, these source materials will continue to be in direct
contact with groundwater. A prohibition on use of deep aquifer groundwater will also be
implemented by this ROD until such time groundwater quality complies with applicable
health-based criteria (e.g., maximum contaminant levels). Prohibitions on groundwater use
would only be rescinded or relaxed if groundwater contaminants no longer exceed
acceptable levels as determined by EPA. The prohibition on groundwater use may be
implemented through a combination of governmental controls (e.g., zoning restrictions or
ordinances) and enforceable use restrictions that run with the land (e.g., a servitude or an
easement that includes use restrictions and is properly recorded).
Long-Term Post-Remedial Action Monitoring. Long-term groundwater monitoring will occur
on a regular basis after the remedial action is complete. The objective of the monitoring
program will be to assess the performance of the Selected Remedy over time and to verify
that the remedy continues to be protective of human health and the environment. At a
minimum, monitoring wells at the downgradient perimeter of the Site (along the
Commencement Bay and Yacht Basin shorelines) will be monitored. Monitoring wells
upgradient of the Site and near key source areas (or former source areas) will also be
required. Monitoring nearshore surface water in Commencement Bay will be required to
assess impacts that discharging groundwater may have on the bay water.
Details of the groundwater monitoring program will be presented in the OMMP. At a
minimum, post-remedial action groundwater monitoring will include measurement of the
following:
• Static groundwater level
• General water quality parameters (temperature, pH, conductivity, salinity, total
dissolved solids, total suspended solids, turbidity, dissolved oxygen, chloride, and
sulfate)
• Metals (arsenic, cadmium, copper, iron, manganese, nickel, lead, zinc)
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PART II SECTION 12
• Organics (DMA area only; aniline, 4-chloroaniline, N-methylaniline, and
N, N-d i me thy 1 a n i 1 i n e)
The OMMP will also address the expectations for groundwater quality improvements at the
point of compliance (see Section 12.1.4) and identify trigger points at which additional
groundwater controls would be considered.
The groundwater monitoring approach will be designed to complement the sediment
monitoring program and monitoring required for OU 02 (e.g., monitoring of the On-site
Containment Facility will be required under OU 02). The monitoring program will be
subject to refinement by EPA based on results of the data collected. Additional details on the
anticipated groundwater monitoring requirements are summarized in Section 12.1.5.
No further active remediation beyond those elements listed above are believed necessary at
this time to address groundwater in OU 06.
12.1.3 Groundwater Cleanup Levels
Cleanup Levels for Shallow Groundwater. The cleanup levels identified for groundwater
discharging from the Site are 3.1 (ig/L for copper and 6 (ig/L for arsenic (Table 12-1). These
cleanup levels are being set to protect marine organisms in Commencement Bay (copper)
and human health via the fish consumption pathway (arsenic). The established regional
background (uncontaminated) concentrations for arsenic and copper in groundwater are
6 (J.g/L and 40 (ig/ L, respectively (EPA, April 1993).
The arsenic cleanup level of 6 (ig/L is higher than the federal National Toxics Rule (NTR)
standard of 0.14 (ig/L for protection of human health based on a fish consumption pathway
(40 C.F.R. Part 131.36). The NTR standard for arsenic (0.14 (ig/L) is a relevant and
appropriate requirement for groundwater but is being waived by EPA for groundwater at
OU 06. The natural background concentration of arsenic in groundwater in the Tacoma
vicinity is 6 (J.g/L (EPA, April 1993). Further, the practical quantitation limit (PQL) for
arsenic in site groundwater has historically been approximately 2 (ig/L. As such, the federal
NTR standard (0.14 (ig/L) is not an achievable or measurable cleanup level for groundwater
at OU 06.
EPA is deferring to the State of Washington's MTCA regulation as the basis for the arsenic
cleanup level (6 (j,g/L). Within the MTCA framework for determining an arsenic cleanup
level for this site, Ecology has determined that the federal NTR standard of 0.14 (ig/L and
MTCA marine surface water criteria of 0.0982 (ig/L are both considered applicable.
However, MTCA mandates that where a risk-based cleanup value is below a natural
background concentration, the cleanup value will be adjusted to equal the natural
background concentration (WAC 173-340-700 (4)(d)). Therefore, even though the NTR and
MTCA marine surface water standards for arsenic are applicable under MTCA, MTCA
supports a 6 (J.g/L cleanup level for arsenic without a need to waive any MTCA
requirement.
The cleanup level of 3.1 (ig/L for copper is protective of human health and marine life in
Commencement Bay. The background concentration for copper in the vicinity of the Site is
significantly higher at 40 (ig/L. However, it is believed that the copper cleanup level of
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PART II SECTION 12
3.1 (ig/L is achievable because concentrations are significantly diluted as groundwater
mixes with seawater in the nearshore portions of the Site aquifers.
MCLs are not considered applicable to shallow groundwater at the Site because (1) most of
the groundwater is categorized as Class III (non-potable due to high TDS levels) and (2) the
Facility is considered a waste management area such that MCLs do not apply inside this
area.
Cleanup Levels for Deep Groundwater. The cleanup levels applicable to the deep
groundwater system are MCLs for metals (Table 12-1). It should be noted that this ROD
imposes an institutional control on use of groundwater from the deep aquifer (see
Section 12.1.2).
12.1.4 Groundwater Point of Compliance
Shallow Groundwater. In accordance with MTCA (WAC 173-340-720(6)(c) and (d)),
compliance with the above-referenced cleanup levels for arsenic and copper in groundwater
discharging from the Site will be determined at a conditional point of compliance.
Normally, MTCA requires that a point of compliance be "established throughout the site
from the uppermost level of the saturated zone extending vertically to the lowest most
depth which could potentially be affected by the site" (WAC 173-340-720(6)(b)). Achieving
groundwater cleanup levels "throughout the site/' however, is not a reasonable expectation
because hazardous substances (e.g., slag and other source materials) will remain on the
upland portion of the Facility based on the OU 02 ROD. In such cases, MTCA allows a
conditional point of compliance "as close as practicable to the source of hazardous
substances, not to exceed the property boundary" (WAC 173-340-720(6)(c)). Further, at such
sites where groundwater discharges into nearby surface water, WAC 173-340-720(6)(d)
indicates that (1) the cleanup levels may be based on protection of surface water and (2) "the
department may approve a conditional point of compliance" that is located within the
surface water as close as technically possible to the point or points where groundwater
flows into the surface water.
WAC 173-340-720(6)(d) further indicates that a conditional point of compliance may be
approved when the following four requirements are met:
• Prohibition on use of a dilution zone to demonstrate compliance (WAC 173-340-
720(6)(d)(i)). Use of a dilution zone to demonstrate compliance with surface water
cleanup levels shall not be allowed.
• Requirement for all known available and reasonable methods of treatment (AKART)
(WAC 173-340-720(6)(d)(ii)). The demonstration of AKART relative to possible
groundwater treatment has been met (see Appendix A, "Analysis of Cost and Benefits of
Groundwater Controls in Addition to the Upland Remedy," to the Historical Summary of
the Evaluation of Groundwater Remedial Alternatives [Hydrometrics, June 2000]).
• Requirement that groundwater discharges not cause violations of sediment quality
standards (WAC 173-340-720(6) (d) (iii)). Technical evaluations completed by the Task
Force demonstrate that Site groundwater discharges are not expected to cause violations
of sediment quality standards (see Group 5 Technical Memorandum, Asarco
Sediment/Groundwater Task Force [Hydrometrics, April 1999]). Furthermore, long-
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PART II SECTION 12
term sediment monitoring will be required to verify that acceptable sediment quality
conditions are maintained after the remedial action is complete.
• Requirement to estimate contaminant flux rates and to address potential
bioaccumulation in marine life resulting from groundwater discharging to surface
water at constituent concentrations below method detection limits (WAC 173-340-
720(6)(d)(iv)). Post-remedial action monitoring conducted under the OMMP will
require estimation of contaminant flux rates and assessment of potential
bioaccumulation of metals in marine life resulting from groundwater discharge.
The above-referenced conditions are met at the Site (including the last requirement to
address potential bioaccumulation in marine life, since associated monitoring and
evaluations will be required by the OMMP). Based on MTCA regulations cited above, and
consultation with Ecology, EPA is setting a conditional point of compliance for groundwater
at the interface of the surface water and the shoreline of Commencement Bay and the Yacht
Basin. Specifically, the conditional point of compliance for the slag aquifer will be at the
interface between the slag (or any overlying shoreline armoring materials) and the surface
water.
Deep Groundwater. The point of compliance for the deep groundwater system will be
throughout the deep aquifer.
12.1.5 Sampling and Analytical Methods for Demonstrating Compliance
Sampling and analytical methods appropriate for demonstrating compliance with
groundwater cleanup levels will be established in the OMMP and in cooperation with
Ecology. It is envisioned that compliance monitoring will require periodic sampling.
Surface Water Samples. Samples will be collected from Commencement Bay and the Yacht
Basin, as close as technically possible to the point where groundwater flows into these
surface water bodies. The exact location, method, and timing of such sampling will be
documented in the OMMP and subject to EPA review and approval.
Groundwater Samples. Groundwater will be collected from a series of monitoring wells
located near the shoreline. Groundwater quality results from these wells will be compared
to surface water quality data collected from adjacent (immediately downgradient) surface
water sampling locations described above. Considering the difference between groundwater
and surface water sampling results from adjacent locations, a factor will be developed to
estimate the degree of dilution/attenuation occurring for each contaminant between the
near-shore monitoring wells and the surface water at the conditional point of compliance.
The compliance concentration at each nearshore well will be established by adjusting
upward the cleanup levels for the protection of the surface water to reflect the dilution and
attenuation expected to occur as groundwater flows from a monitoring well to the shoreline.
These adjusted cleanup levels will be compared to the monitoring well data for compliance
purposes. Appropriate evaluations will be required to determine a technically defensible
dilution/ attenuation factor for each monitoring well location.
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PART II SECTION 12
12.2 Sediment
EPA's Selected Remedy is a combination of capping in the Near shore/Offshore and
Northshore areas and dredging of the Yacht Basin with onsite upland disposal of the
dredged sediments.2 The affected areas are shown in Figure 12-1. The rationale for the
Selected Remedy is provided below. In addition, upland source control activities being
conducted under the OU 02 remedial action need to occur prior to sediment remediation so
that the possibility of sediment recontamination is minimized.
12.2.1 Sediment Remedy Elements
The Selected Remedy for sediments includes five elements: capping, dredging, no action,
institutional controls, and long-term monitoring.
Capping. Capping is the Selected Remedy for the Nearshore/Offshore (Alternative S-1C)
and Northshore (Alternative S-3C) areas. Capping is the Selected Remedy because it will
isolate contaminated materials from the benthic organisms. Capping is the most practicable
solution given the constraints associated with the depth of sediment contamination and the
character of the subtidal slopes. Approximately 88,000 square yards (18 acres) of existing
contaminated sediments within the severely impacted portion of the Nearshore/Offshore
area (including the sediment under and adjacent to the existing piers) will be capped with a
minimum of 3 feet of clean sediment. Approximately 7,000 square yards (1.5 acres) of the
severely impacted portion of the Northshore area will also be capped with a minimum of
3 feet of clean sediment.3
The borrow source(s) for the cap material will be determined during remedial design and
will originate from either a marine (in-water) or upland source. The cap will be designed
such that it provides chemical isolation, is physically stable, and provides a cap surface that
allows recolonization of benthic communities. In order to achieve this, the design will assess
the geotechnical aspects of the area, as well as the erosional nature of the cap materials used,
depth of bioturbation, future use of the area, and other design considerations. The results of
the pilot cap study (Parametrix, February 2000) will be considered during the remedial
design process. Placement of the cap is expected to be relatively easy to implement. Similar
caps have been successfully completed elsewhere in the Puget Sound area.
Dredging. The Selected Remedy for the Yacht Basin is Alternative 2D, dredging and upland
disposal. Dredging is the Selected Remedy for the Yacht Basin because it would remove the
contaminated material, and removal tends to be a more controlled remedy than in-water
containment. Furthermore, without prior dredging, capping in the marina is not possible
because the cap would interfere with and be damaged by navigation.
An area approximately 75,000 square yards (15.5 acres) will be dredged in the Yacht Basin
because it was determined to be a severely impacted area. It is estimated that approximately
1 to 2 feet of material (up to 50,000 cubic yards) will require removal. The exact depth of
dredging will be based upon information obtained from core samples that are collected
during the summer of 2000. Post-dredging confirmatory sampling will also be required to
2 Current plans call for capping in the Northshore area, however, depending on remedial design considerations, this small area
may be dredged.
3 See footnote 2.
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PART II SECTION 12
verify that contaminated sediments have been adequately removed. If all of the
contaminated sediments in the Yacht Basin cannot be practicably dredged or if slag is
encountered, then the remaining contaminated sediment areas will be capped in place to the
extent practicable.
The dredged material will be contained upland in OU 02 (Figure 1-2). OU 02 redevelopment
activities have reserved capacity for these dredged spoils. The precise location will be
detailed in the construction phasing schedule for OU 02. Redevelopment includes site
grading and the installation of a low-permeability soil cap that will contain the sediments
dredged from the Yacht Basin.
Material dredged from the Yacht Basin will be contained temporarily on the upland portion
of the Facility and dewatered. Dewatered sediments will be permanently contained in an
upland location in the central part of the Facility. Sediments contained in the upland
location will be permanently covered with the low-permeability cap being installed across
the Facility under the OU 02 remedial action. Effluent derived from the dewatering of
dredged material will be discharged into the Yacht Basin or into Commencement Bay in
accordance with BMPs and applicable water quality requirements. The specific sediment
dewatering methods and requirements for management of discharges from dewatering
effluent will be defined during remedial design and implemented during construction.
The dewatered sediments are currently scheduled to be placed beneath the upland low-
permeability cap no later than November 30, 2004 as stipulated by "Amendment Number
One" to the Asarco Smelter Consent Decree (Lodged in the District Court of Washington,
June 2000) and a "Modification Agreement" signed by EPA and Asarco (EPA, November
1999). If either the OU 02 or OU 06 remediation schedules are such that the marine
sediments cannot be placed under the cap by this date, the sediments may need to be
permanently disposed of at an appropriate offsite location approved by EPA. Assuming the
sediments are permanently contained onsite as planned, the mobility of the contaminants
would be minimized as the dredged sediments will not be in contact with water as they will
be placed at an elevation above the highest anticipated groundwater level. The operations
and monitoring requirements for the OU 02 remedial action will include appropriate
monitoring of the upland cap to verify its long-term effectiveness. Further, there will be a
plan prepared under the OU 02 operations and monitoring program to address any failure
or potential failure of the cap covering the dredged sediments.
No Action. No remedial action is planned for sediments offshore of the Breakwater
Peninsula area (approximately 85,000 square yards or 17.5 acres). Sediments within this area
(Figure 12-1) are within the Contaminant Effects Area. However, no remedial action is
planned because of inherent engineering/construction impracticability associated with this
area. The presence of steep slopes (as much as 50 percent slope) make capping or dredging
infeasible. Further, the stability of a cap on such a steep slope is questionable. In addition,
dredging is not possible because the entire Breakwater Peninsula would need to be removed
since it is constructed entirely of slag (up to 125 feet thick).
Institutional Controls. All offshore capped areas will be designated as "no anchor" zones.
This remedy is being selected because it will ensure long-term protection of capped areas.
The no anchor designation will apply to commercial vessels using "whale-tail" type anchor,
which have the capacity to break through the cap material and expose contaminated
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PART II SECTION 12
sediment. This institutional control will be implemented though federal rule-making by the
U.S. Coast Guard and the U.S. Army Corps of Engineers in consultation with the
Washington Department of Natural Resources. The rule-making will be subject to public
comment.
Long-Term Post-Remedial Action Monitoring. Monitoring will occur on a long-term, regular
basis after the remedial action is complete to verify the performance of each remediation
area and the adjacent areas. This remedy is being selected because long-term monitoring of
the offshore sediment cap will be necessary to confirm that the cap is isolating the
contaminated sediments from marine life. Long-term monitoring is planned over a period of
decades.
Long-term monitoring will occur off the Breakwater Peninsula since it cannot be remediated
due to technical impracticability.
Long-term monitoring will also occur in those areas adjacent to the active remediation areas
(the Moderate Impacts Area and the Contaminant Effects Area), where RI findings indicate
exceedances of the SMS biological criteria. Monitoring is necessary to evaluate if long-term
biological change is occurring in these areas, to monitor the long-term effectiveness of the
sediment remedy, and to ensure the RAOs are being met. These evaluations will be
conducted in accordance with the SMS and the preponderance-of-evidence approach, as
discussed in Section 7.2.2. These areas will be monitored over a long duration so trends can
be identified and responded to as necessary.
An Operation, Maintenance, and Monitoring Plan (OMMP) will be prepared as part of the
remedial design and implemented as part of the remedial action. The OMPP will identify
inspection and monitoring procedures to verify that the elements of the remedy are
performing as intended or, if they are not, to identify needed repairs on a timely basis. The
cap's physical integrity, particularly its thickness, will be verified on a regular basis.
Inspections will be also conducted following major storm or earthquake events that could
potentially affect the cap. Chemical analysis of cap materials will be conducted to verify that
contaminants are not accumulating in the upper part of the cap, where the marine
organisms live. Biological data will also be collected including abundance evaluations,
bioassays, and tissue analyses.
The OMMP will identify monitoring requirements and conditions applicable to the
moderate impact areas to see that RAOs are achieved in those areas not capped or dredged.
For example, if long-term monitoring indicates contamination of marine sediments that is
inconsistent with RAOs, or that the cap is eroding, action will be taken as appropriate.
Likely responses to cap erosion may be the placement of additional cap material or
armoring materials to reduce erosion. Specific actions and associated "trigger" conditions
will be identified in the OMMP. In addition, more source control measures could be
instituted upland to reduce the rate of cap recontamination (i.e., additional groundwater
diversion measures). If EPA determines through long-term monitoring that the selected
remedies are not protective, EPA can amend this ROD or issue an Explanation of Significant
Difference (ESD) to modify the remedy as necessary.
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PART II SECTION 12
12.2.2 Sediment Cleanup Levels
Remediation cleanup levels identified for the marine sediments at OU 06 are based upon the
characteristics of each specific area and the type of remedy selected for that area. The
sediment cleanup levels will also be used to measure compliance under the long-term
monitoring program . The State of Washington's SMS (WAC 173-340), including the
Sediment Quality Standards (SQS), the Cleanup Screening Levels (CSL), and the biological
impact conditions determined by the preponderance-of-evidence approach (Section 7.2.2)
will be used as cleanup levels for sediment. The specific remedy units (Figure 9-2) and their
corresponding cleanup levels are summarized in Table 12-2 and are described below:
• Capping for the Nearshore/Offshore and Northshore Areas. The cleanup levels for
these areas have been derived from the results of the preponderance-of-evidence
approach, which has also been used to define the extent of active remediation (capping).
For long-term monitoring, the SQS will be applied to ensure that the cap is supporting a
healthy and diverse biological community.
• Dredging for the Yacht Basin. The cleanup levels selected for the Yacht Basin will be the
SMS. These will be used to determine the vertical and horizontal extent of the active
remediation (dredging). RI data suggest that fine-grained sediments like those present in
the Yacht Basin do not typically exhibit biological effects when arsenic and copper
concentrations are below the CSL. Therefore, the CSL criteria for these metals will be
used as their cleanup levels. RI data also suggest that biological effects in fine-grained
sediments may be more sensitive to sediments with zinc and lead contaminants.
Therefore, the SQS have been selected as cleanup levels for these two metals. The above-
referenced cleanup levels for arsenic, copper, lead, and zinc will also be used during
long-term monitoring to ensure that the RAOs are met in the Yacht Basin.
• Moderate Impact and Contaminant Effects Areas. Long-term monitoring will be
required for marine sediments at OU 06 that will not undergo active remediation.
Monitoring is required to ensure that sediment conditions continue to meet RAOs. The
preponderance-of-evidence approach will continue to be applied to these areas in order
to evaluate the long-term biological conditions, monitor the long-term effectiveness of
the overall remedy to these portions of the Site, and to ensure the RAOs are being met.
12.3 Expected Outcomes of the Selected Remedy
It is expected that the Selected Remedy will protect human health and the environment
consistent with the RAOs outlined in Section 8.
Source control measures will reduce the leaching of contaminants to groundwater.
Installation of a low-permeability cap, surface and groundwater water controls, and
abandonment or replacement leaking underground piping is expected to reduce
groundwater flow recharge. The expected effect is an estimated 75 to 95 percent reduction in
the contaminant loading to Commencement Bay from groundwater discharge. It is expected
that groundwater cleanup levels for arsenic (6 (ig/L) and copper (3.1 (ig/L) will eventually
be reached at the conditional point of compliance after the remedial action is completed and
groundwater conditions have stabilized.
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PART II SECTION 12
Although achievement of groundwater cleanup levels is expected near the shoreline due to
dilution effects of adjacent marine waters, the quality of shallow groundwater over most of
the Site is not expected to change significantly. Significant improvements in groundwater
quality are not expected because source materials (e.g., slag) will remain in place
permanently as part of the OU 02 ROD (EPA, March 1995).
As anticipated by the remedial design for OU 02, the upland part of the Facility will be
developed for commercial and recreational use. Public access will be provided to the
waterfront and intertidal areas in selected locations. The underlying shallow groundwater
included in OU 06 will not be available as a drinking water source. Deep groundwater
included in OU 06 will not be available as a drinking water source until such time
groundwater quality complies with applicable health-based criteria (e.g., maximum
contaminant levels).
It is expected that the remedial measures employed to address sediment contamination will
result in attainment of cleanup levels for arsenic, copper, lead, and zinc consistent with SMS
(Table 12-2). For areas subjected to active remedial measures (e.g. the Yacht Basin from
dredging and the Near shore/Offshore area and Northshore area from capping),
concentrations of COCs will be reduced immediately upon the removal and capping of
contaminated sediments. Recolonization of these areas is expected to occur rapidly as
demonstrated in the Cap Pilot Study (Parametrix, February 2000). An overall improvement
in marine sediments and benthic community structure is expected to occur in all impact
areas over several years. The Yacht Basin will continue to be suitable for use by recreational
watercraft; however, this use will continue to limit the suitability of this habitat for some
organisms.
Long-term monitoring as defined in the OMMP will identify inspections and monitoring
procedures to verify that the elements of the remedy are performing as intended.
12.4 Summary
The Selected Remedy for OU 06 is composed of four alternatives to address groundwater
and marine sediments (Alternatives GW-B, S-1C, S-2D, and S-3C). The Selected Remedy
complies with statutory requirements under CERCLA, meets the CERCLA threshold
criteria, and provides the best balance with respect to CERCLA's balancing and modifying
criteria. EPA believes the Selected Remedy will protect human health and the environment,
comply with ARARs (except as waived by this ROD), be cost-effective, and utilize
permanent solutions to the maximum extent practicable.
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PART II SECTION 13
13 Statutory Determinations
Under CERCLA Section 121 and the NCP, the lead agency must select remedies that are
protective of human health and the environment, comply with applicable or relevant and
appropriate requirements (unless a statutory waiver is justified), are cost-effective, and
utilize permanent solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. In addition, CERCLA includes a preference
for remedies that employ treatment that permanently and significantly reduces the volume,
toxicity, or mobility of hazardous wastes as a principal element and a bias against off-site
disposal of untreated wastes. The following sections discuss how the Selected Remedy does
or does not meet these statutory requirements.
13.1 Protection of Human Health and the Environment
The Selected Remedy (Alternative GW-B for groundwater and Alternatives S-1C, S-2D, and
S-3C for sediments) will protect human health and the environment by minimizing the
discharge of contaminants to Commencement Bay via groundwater and removing or
isolating contaminated sediments in Commencement Bay and the Yacht Basin. When
combined with the remedy being implemented for OU 02 under the 1995 ROD (EPA, March
1995), the remedy will reduce the threat of exposure to the chemicals of concern to both
humans and marine organisms. Cleanup levels for sediment are expected to be met
immediately upon completion of the remedial-action activities. However, the biological
community will require time to recolonize the areas where sediment is covered by cap
material or is impacted by dredging. Contaminant concentrations in groundwater are
expected to decrease gradually with time. Cleanup levels for groundwater will not likely be
met until several years after the remedial action is complete.
13.2 Compliance with Applicable or Relevant and Appropriate Requirements
(ARARs)
The Selected Remedy is expected to comply with federal and state ARARs with the
exception of arsenic in groundwater discharging to Commencement Bay, which is not
expected to comply with the federal NTR marine water standard of 0.14 (ig/L (40 C.F.R.
Part 131.36). A list of ARARs for OU 06, including the justification for the NTR waiver for
arsenic, are provided below.
State of Washington Model Toxics Control Act (MTCA) (WAC 173-340)
Key sections of MTCA applicable requirements are listed below:
WAC 173-340-360(4) — Identifies the order of preference of cleanup technologies,
including treatment as the highest preference.
WAC 173-340-360(6) — Addresses selection of a cleanup that provides for a reasonable
restoration time frame and identifies factors to be considered when establishing that
time frame.
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PART II SECTION 13
• WAC 173-340-440 — Requires institutional controls where active cleanup measures (e.g.,
treatment) will not attain MTCA cleanup levels or where a cap is used to contain
contaminants above MTCA cleanup levels.
• WAC 173-340-720—Sets groundwater cleanup standards and guides selection of the
point of compliance.
• WAC 173-340-730—Sets surface water cleanup standards and guides selection of the
point of compliance. Applicable as both sediments and groundwater may impact surface
water quality of Commencement Bay.
Minimum Standards for Construction and Maintenance of Water Wells (R.C.W. § 18.104,
WAC 173-160)
Well construction regulations establish minimum standards for water well construction.
This regulation will be applicable to wells constructed for groundwater monitoring
purposes. This regulation is also applicable to the decommissioning of existing or future
wells.
Regulation and Licensing of Well Contractors and Operators (R.C.W. § 18.104, WAC 173-162)
These regulations apply to all water well contractors and operators who are providing well
installation, maintenance, or abandonment services within the State of Washington.
General Regulations for Air Contaminant Sources (WAC 173-400)
This regulation requires Best Management Practices to be employed, including covering
stockpiles, cleaning trucks prior to leaving the Site, and monitoring air emissions. As an
example, these regulations will be applicable to handling and dewatering dredged
sediments.
U.S. Fish and Wildlife Coordination Act (16 U.S.C. § 661 et seq.)
Commencement Bay provides potential habitat for certain endangered species and is used
as a salmonid migratory route. This Act prohibits water pollution with any substance
deleterious to fish, plant life, or bird life, and requires consultation with the U.S. Fish and
Wildlife Service and appropriate state agencies prior to construction of the remedy. Criteria
are established regarding site selection, navigational impacts, and habitat remediation. This
statute is applicable to capping and dredging to be performed in Commencement Bay.
Safe Drinking Water Act (42 U.S.C. § 300)/National Primary Drinking Water Regulations
(40 C.F.R. Part 141 Subpart B)/Water Quality Standards for Ground Waters of the State of
Washington (WAC 173-200-040)
The federal primary drinking water standards adopted by the State of Washington set
maximum contaminant levels (MCLs). MCLs are the maximum permissible levels of
contaminants allowed in drinking water based on the prevention of adverse health effects.
Class III groundwater (non-potable due to total dissolved solids greater than 10,000 mg/L)
prevail in the shallow aquifer system and are not subject to MCLs. However, MCLs are
applicable for those portions of the deep aquifer where Class II (potable) groundwater is
present.
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PART II SECTION 13
Federal Water Pollution Control Act/Clean Water Act (33 U.S.C. §§ 1251-1376; 40 C.F.R. Parts
100-149)
Acute marine criteria are relevant and appropriate requirements to control discharges to
marine surface water during cap placement and sediment dredging.
Federal Clean Water Act (33 U.S.C. § 1251 et. seq.)/Washington State Water Quality Standards
for Surface Waters (WAC 173-201 A)
Surface water quality standards for protection of human health and the aquatic life will be
applicable to discharges to surface water during cap placement and sediment dredging. The
water quality standards also guide the quality of groundwater that will discharge to
Commencement Bay for purposes of protecting marine organisms.
National Toxics Rule (40 C.F.R. Part 131.36)
The federal NTR standard for arsenic of 0.14 (ig/L (40 C.F.R. Part 131.36) is a relevant and
appropriate requirement for groundwater. EPA is waiving the NTR for arsenic because
compliance with the requirement is technically impracticable from an engineering
standpoint because the NTR level is neither achievable nor measurable at this site (40 C.F.R.
Part 3000.430 (f)(ii)(C)(3)). Specifically, the NTR standard is being waived because the
natural background concentration of arsenic in groundwater in the Tacoma vicinity is
6 (J.g/L (EPA, April 1993). Further, the PQL for arsenic in site groundwater has historically
been approximately 2 (ig/L. See Section 12.1.3 for additional discussion addressing the basis
for this ARAR waiver.
Washington Sediment Management Standards (WAC 173-204)
Chemical concentration and biological effects criteria are established for Washington State,
including Puget Sound sediments, and are applicable to sediment remediation.
State Water Pollution Control Act (R.C.W. § 90.48)/Water Resources Act (R.C.W. § 90.54)
Requirements for the use of all known, available, and reasonable technologies for treating
wastewater prior to discharge to state waters are applicable to any dewatering of marine
sediment prior to upland disposal. Section 401 requires certification for activities conducted
under Section 404 authorities. The substantive requirements of a certification determination
are applicable.
Construction in State Waters, Hydraulic Code Rules (R.C.W. § 75.20; WAC 220-110)
Hydraulic project approval and associated requirements for construction projects in state
waters have been established for the protection of fish and shellfish. Substantive permit
requirements are applicable to cap placement. The technical provisions and timing
restrictions of the Hydraulic Code Rules are applicable to cap placement and dredging.
State Discharge Permit Program/NPDES Program (WAC 173-216 and -220)
The Washington State NPDES program provides conditions for authorizing direct
discharges to surface waters and specifies point source standards for such discharges. As an
example, these standards are applicable to discharges to surface waters resulting from
sediment dewatering operations during dredging and disposal work.
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PART II SECTION 13
Whole Effluent Toxicity Testing and Limits (WAC 173-205)
Establishes whole effluent toxicity limits in accordance with R.C.W. § 90.48.520, 40 C.F.R.
Part 122.44(d), and 40 C.F.R. Part 122.44(e) for inclusion into National Pollutant Discharge
Elimination System (NPDES) permits to protect aquatic life through the implementation of
all known, available, and reasonable methods of prevention, control and treatment of
toxicants and through the attainment of state water quality standards. The requirements are
applicable if it is determined that the substantive requirements of a NPDES permit must be
met for diversion of contaminated and treated water from sediment dewatering.
Federal Clean Water Act Dredge and Fill Requirements; Sections 401 and 404 (33 U.S.C. § 401 et
seq., 33 U.S.C. §§ 1251-1316; 33 U.S.C. § 1413; 40 C.F.R. Parts 230 and 231; 33 C.F.R.
Parts 320-330)
These regulations provide requirements for the discharge of dredged or fill material to
waters of the U.S. and are applicable to any in-water work. The sediment dredging and
capping elements of the Selected Remedy are subject to the requirements of Section
404(b)(1). Mitigation requirements associated with the remedy selected for OU 06 will be
addressed as part of the 404 process. A Biological Assessment (BA) is currently being
prepared by EPA to meet the substantive requirements of the Section 404 Permit. Mitigation
is also required to compensate for the loss of approximately 0.2 acre of intertidal habitat in
the Yacht Basin.
Federal Endangered Species Act of 1973 (16 U.S.C. § 1531 et seq., 50 C.F.R. Parts 200
and 402)/Marine Mammal Protection Act (16 U.S.C. § 1361 et. seq.)
This regulation is applicable to any remedial actions performed at the Site, as this area is
potential habitat for threatened and/or endangered species. Best Management Practices
(BMPs) required to ensure full compliance with ESA requirements will be addressed and
implemented. EPA is currently preparing a BA to meet the substantive requirements of the
Section 404 Permit. At this time EPA is informally consulting with the National Marine
Fisheries and the U.S. Fish and Wildlife Service on the remedial actions.
Rivers and Harbors Appropriations Act (33 U.S.C. § 403, 33 C.F.R. Part 322)
Section 10 of this Act establishes permit requirements for activities that may obstruct or alter
a navigable waterway; activities that could impede navigation and commerce are
prohibited. These substantive permit requirements are applicable to dredging and capping.
Shoreline Management Act (R.C.W. § 90.58, WAC 173-14 through 173-28); Coastal Zone
Management Act (16 U.S.C. § 1451 et seq., 15 C.F.R. Part 923)
These statutes and regulations are applicable to capping activities in the shoreline area.
State Aquatic Lands Management Laws (R.C.W. § 79.90-79.96, WAC 332-30)
The State Aquatic Lands Management Laws are applicable. The final remedy must be
consistent with state laws that promote environmental protection, public access, water
dependent uses, and uses of renewable resources that generate revenue to the state in a
manner consistent with these management goals.
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PART II SECTION 13
Resource Conservation and Recovery Act (40 C.F.R. Part 261.4(g))
This regulation is applicable and provides an exemption in determining that contaminated
sediments dredged under the requirements of Section 404 of the Clean Water Act are not
classified as RCRA hazardous waste.
Native American Land Claims Acts Including Washington Indian (Puyallup) Land Claims
Settlement Act (25 U.S.C. § 1773)/Puyallup Tribe of Indians Settlement Act of 1989
The Puyallup Tribe of Indians Settlement Act of 1989 is relevant and appropriate in that the
Puyallup Tribe maintains certain rights pertaining to fisheries resources and associated
habitat.
Archeological and Historical Preservation Act (16 U.S.C. § 4699)
This statute is applicable and requires that significant scientific, pre-historical, or
archeological data be preserved if present on the Site.
Federal Clean Air Act (42 U.S.C. § 7401 et. seq., 40 C.F.R. Part 50)/Washington Clean Air Act
(R.C.W. § 70.94, WAC 173-400 and -460)
Air quality statutes and regulations would be applicable if dust is generated as part of
sediment dewatering/handling or if emissions are created by facilities used to treat water
produced during sediment dewatering.
To Be Considered (TBCs)
TBC items are state and local ordinances, advisories, guidance documents or other
requirements that, although not ARARs, may be used in determining the appropriate extent
and manner of cleanup. Generally, TBC requirements are used when no federal or state
requirements exist for a particular situation. A list of TBCs for the Site include:
• Puget Sound Water Quality Management Plan. Defines objectives for standards
regarding the confined disposal of contaminated sediment. Although the Selected
Remedy does not include a CAD, the standards presented in the Puget Sound Water
Quality Management Plan may be useful with respect to the design and construction of a
sediment cap (e.g., selection of import cap material).
• Standards for Confined Disposal of Contaminated Sediments, Washington
Department of Ecology (January 1990). Guidelines for assessing the suitability of
dredged material for unconfined disposal relevant to cap material specifications.
• Area of Contamination Interprogram Policy, Washington Department of Ecology.
Guidelines for management of dredged sediment meeting the criteria as a state
dangerous waste.
• Sediment Cleanup Standards Users Manual, Washington Department of Ecology.
Guidance for implementing the sediment cleanup decision process for contaminated
sediments.
• Sediment Source Control Standards Users Manual, Washington Department of
Ecology (June 1993). Guidance for implementing the Sediment Source Control
Standards.
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PART II SECTION 13
• Local Shoreline Master Program. Guidelines for managing development of shorelines
to preserve natural resources while protecting public access and navigation.
• Development of Sediment Quality Criteria for the Protection of Human Health: Tier I
Report, Washington State Office of Toxic Substances (1995). Proposes draft sediment
quality standards based on risks to humans.
13.3 Cost-Effectiveness
The estimated present worth cost for the Selected Remedy is $19.2 million and is considered
cost-effective. The $19.2 million estimated cost is divided between groundwater and marine
sediment remedies as follows:
Institutional Controls and Long-Term Monitoring
Components of Groundwater Remedy (Alternative GW-B) $1.8 million
Sediments Remedy, Nearshore/Offshore Area (Alternative S-1C) $11.6 million
Sediments Remedy, Yacht Basin (Alternative S-2D) $5.1 million
Sediments Remedy, Northshore Area (Alternative S-3C) $0.7 million
Total $19.2 million
This estimate does not include the cost for any OU 02 remedy element that may benefit
groundwater.
In making a determination regarding cost-effectiveness, the following definition was used:
"A remedy shall be cost-effective if its costs are proportional to its overall effectiveness."
(NCP, Section 300.430(f)(l )(ii)(D)). This was accomplished by evaluating the "overall
effectiveness" of those alternatives that satisfied the threshold criteria (i.e., were both
protective of human health and the environment and ARAR-compliant). Overall
effectiveness was evaluated by assessing three of the five balancing criteria in combination
(long-term effectiveness and permanence; reduction in toxicity, mobility, and volume
through treatment; and short-term effectiveness). Overall effectiveness was then compared
to costs to determine cost-effectiveness. The relationship of the overall effectiveness of this
remedial alternative was determined to be proportional to its costs and hence this
alternative represents a reasonable value for the money to be spent.
13.4 Utilization of Permanent Solutions and Alternative Treatment (or Resource
Recovery) Technologies to the Maximum Extent Practicable
EPA has determined that the Selected Remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized in a practicable manner at
the Site. Of those alternatives that are protective of human health and the environment and
comply with ARARs, EPA has determined that the Selected Remedy provides the best
balance of trade-offs in terms of the five balancing criteria, while also considering, the
statutory preference for treatment as a principal element. EPA also considered the bias
against offsite treatment and disposal, and considered state and community acceptance
when selecting the preferred remedy.
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PART II SECTION 13
13.5 Preference for Treatment as a Principal Element
Treatment of contaminated sediment to reduce toxicity or mobility of contaminants is not
considered feasible. As stated previously, treatment was evaluated for sediment cleanup,
however it was not considered further for the following reasons: First, in order to treat the
sediments, they must be removed. This is difficult in the Near shore/Offshore area of OU 06
because the contamination is very deep. Therefore, the chance of leaving contamination
behind is very high. Second, since slag was poured to create the shoreline in portions of the
Nearshore area, dredging in this area would be difficult due to slope stability issues. Third,
the net benefit of treating the sediments is in question as the slag pieces within the sediment
matrix are already in a relatively immobile form (e.g., the slag does not tend to be
bioavailable; see discussion in Section 5.2). Fourth, costs associated with treatment of the
Yacht Basin sediments would be disproportionate to the costs associated with the current
upland disposal plan.
13.6 Five-Year Review Requirements
Because this remedy will result in hazardous substances, pollutants, or contaminants
remaining onsite above levels that allow for unlimited use and unrestricted exposure, a
statutory review will be conducted within five years after initiation of the remedial action to
ensure that the remedy is, or will be, protective of human health and the environment.
Additional groundwater interception or other controls may be required in the future if it is
determined that groundwater cleanup levels are not being met and additional groundwater
capture is practicable considering the expected reduction in risk to human health and the
environment. This issue will be assessed as part of the Five-Year Review process.
13.7 Documentation of Significant Changes from Preferred Alternative of
Proposed Plan
The Proposed Plan for the Asarco Sediments/Groundwater OU 06 was released for public
comment in January 2000. A public meeting was held on February 10, 2000, to present the
preferred remedy and solicit comments from the public. The Proposed Plan identified the
Preferred Remedy for OU 06 as comprising Alternative GW-B (groundwater) and
Alternatives S-1C, S-2D, and S-3C (sediments). EPA carefully reviewed all written and oral
comments provided during the comment period. Based on the comments received, two
minor changes have been incorporated into the Selected Remedy:
• Reduction of Sediment Cap Thickness from 1 Meter to 3 Feet. The Preferred Remedy
identified in the Proposed Plan called for a 1-meter (39-inch) cap in the Nearshore/
Offshore Area (18 acres). The Selected Remedy identified in this ROD calls for this area
to be capped with 3 feet (36 inches) of clean material. This change is based on a re-
evaluation of the depths to which burrowing organisms are reported to penetrate the
cap. This re-evaluation determined that a 36-inch cap will effectively isolate the
contaminated sediments from the biota and overlying water as well as a 39-inch cap.
Therefore, the Selected Remedy will be protective of human health and the environment.
• Possible Dredging of the Northshore Area. The Preferred Remedy identified in the
Proposed Plan called for capping contaminated sediments in the Northshore area
(1.5 acres). The Selected Remedy calls for this area to be capped but acknowledges that
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PART II SECTION 13
dredging may be determined to be appropriate depending on engineering
considerations assessed during the remedial design. As such, dredging will be re-
evaluated as part of the remedial design process. Either capping or dredging would be
protective of human health and the environment.
The above-referenced remedy modifications could have been reasonably anticipated based
on the information in the Proposed Plan. Therefore, additional public comment on these
changes is not required.
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Responsiveness Summary
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Introduction
This Responsiveness Summary provides EPA's responses to comments on the Proposed
Plan for the Asarco Sediments/Groundwater Operable Unit 06 (EPA, January 2000a).
Comments were received from citizens, corporate and community organizations, and
government agencies. The Responsiveness Summary includes responses to both written and
oral comments received during the 60-day comment period (January 26 to March 25, 2000).
Copies of the written comments received are provided in Appendix D. Oral comments were
received during the public meeting on February 10, 2000. The transcript from this meeting is
available in EPA's Administrative Record for the Asarco Sediments/Groundwater Operable
Unit 06.
EPA has grouped the comments and corresponding responses into 15 topics:
• Site Risks
• Sediment Impact/Remediation Area
• Alternatives to Sediment Capping
• Protectiveness and Effectiveness of Sediment Capping Remedy
• Sediment Cap Thickness
• Sediment Dredging
• Institutional Concerns Regarding Sediment Capping
• Groundwater Extraction and Treatment
• Remediation Goals/Levels (Groundwater)
• Remediation Goals/Levels (Sediment)
• Remedy Costs
• Endangered Species Act and Biological Assessment Issues
• Natural Resource Mitigation
• Long-Term Monitoring
• Other Comments
The Responsiveness Summary addresses each comment received. The comments are
numbered for convenience and cross-referencing purposes. They are reproduced as received
by EPA (written comments) or as cited in the transcript of the February 10, 2000 public
meeting (oral comments). Exceptions are EPA annotations in the comments; these are noted
as italicized text within brackets (e.g., [EPA annotation...]). Comment letters or oral
comments addressing more than one issue have been divided and presented under the
above-referenced topic headings. Each comment is presented in non-italicized font. EPA
responses are italicized. Also note that references to page and section numbers in the
comments refer to the Proposed Plan.
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PART III
Site Risks
Comment No. 1
Comment: Pg. 9, 3rd full para. This paragraph compares site tissue concentrations to
reference tissue concentrations and ignored the sections of the Phase 1 Data Report that
showed "...the site station tissue chemistry was found to be indistinguishable from the
reference station tissue chemistry in all cases (see Table 8-3)." In other words, the differences
were not statistically significant. Further, it is not appropriate to state that tissue
concentrations are elevated without providing any risk context. Anyone that only gets this
far reading the document may not learn that these tissue concentrations are acceptable using
EPA's risk criteria, as stated later in the Proposed Plan.
Response: EPA acknowledges that extensive details regarding site risk are not provided in the
Proposed Plan. However, the text in the Proposed Plan is accurate as written, and the reader is
referred to the Phase 1 report for additional details regarding site risk.
Comment No. 2
Comment: 5.1 Human Health Screening Risk Assessment
Sediments: In determining human health risks associated with eating fish caught within the
site, the low end range (1 gram per day of fish) was selected to represent the consumption of
an infrequent sports fisherperson who might eat fish from the waters off the facility a few
times each year. The greater Commencement Bay area hosts a number of ethnic
communities who routinely fish for subsistence. Because of easy access, the waters along
Ruston Way/Asarco/Point Defiance are a popular fishing spot for members of these
communities. We believe that the assumption of 1 gram per day of fish does not consider
the subsistence harvest practiced by members of these communities and needs to be
increased accordingly.
Response: EPA concurs. The risk associated with recreational and subsistence users was addressed
in the risk assessment. In this risk assessment, EPA assumed 290 grams per day offish consumption
for the subsistence user. This risk is discussed in the third paragraph on page 12 of the Proposed Plan
and Section 7 of this ROD.
Comment No. 3
Comment: (Section 8.1) Do you understand why fish tissue remained below risk thresholds
even though groundwater exceeds human health risk based levels for fish consumption? If
not, how can you be sure that the environmental conditions which allow this to happen will
remain constant?
Response: The human health risk values were calculated from fish tissue collected at the Site. In
other words, the fish collected were exposed to site groundwater and the waters and marine sediments
of Commencement Bay. The fish collected were not just exposed to groundwater. Therefore, collection
of site-specific tissue data is the most representative of actual site conditions. The groundwater risk
numbers referenced above assume that the organisms will be exposed to contaminated groundwater
only, and not to surface water and sediment as well. Therefore, the data collected as part of the site
investigations are most applicable to the actual site conditions.
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As for future site conditions, EPA believes that the conditions at the Site will, at least, remain the
same, or improve due to the remedial actions planned for the Site.
Sediment Impact/Remediation Area
Comment No. 4
Comment: As Asarco understands the Expanded RI/FS data and the Proposed Plan, all
impacted areas that require remediation and can practicably be remediated will be
remediated. However, the use of the terms "moderately impacted" and "minimally
impacted" in the Proposed Plan are potentially misleading and may imply that some
impacted areas will not be remediated. These terms also seem to ignore the sophisticated
approach that EPA and Asarco have taken to identify and characterize areas with
contaminant effects. Asarco would prefer that areas simply be identified as "impacted" and
"non-impacted" as determined by the preponderance of evidence approach and the
extensive sediment effects data.
The approach to identification of impacted areas presented by Asarco in Phase 1 of the
Expanded RI/FS was substantially more complex and complete than the approach
described in the Proposed Plan. In comparison to the Phase 1 approach, it is extremely
simplistic to use "benthic results to identify the most highly impacted areas...." Asarco
prefers to base impact determinations on all of the detailed sampling and data analysis
work that Asarco and EPA have conducted rather than the highly simplistic approach
described in the Proposed Plan, which is only a slight modification of the Sediment
Management Standards (SMS).
In Phase 1, Asarco evaluated measures of chemistry, bioassays, benthic community results
and other types of sampling (e.g., pore water chemistry, pore water bioassays, tissue
chemistry, sequential extraction analyses of slag) to determine those measures that appeared
to be most highly correlated. The benthic results were evaluated in many ways including
relatively simplistic SMS measures and much more powerful data analysis tools (e.g.,
proportional similarity index and principal coordinates analysis). All of these measures
were evaluated and chemistry, sediment bioassays, and numerous measures of benthic
abundance and diversity were used in the final preponderance-of-evidence approach. In
this approach, some benthic community measures were given greater weighting than other
benthic measures, sediment bioassays, and chemistry. Bulk sediment chemistry results were
given the least weight in the preponderance-of-evidence approach. Some other evidence
was judged to be inappropriate for use in cleanup decisions.
The purpose of the preponderance-of-evidence approach was to define those areas
exhibiting contaminant effects. No "moderate impact areas" were defined in the Phase 1
Report. The preponderance-of-evidence either "tipped the scale" into contaminant effects
designation or it did not. Thus, one significantly different bioassay result or a particularly
high chemistry result does not indicate a "moderately impacted" area. In such cases, the
preponderance of other evidence (mainly various measures of the benthic community)
indicates that this area is not impacted. Defining stations that have one significantly
different bioassay and/ or chemistry result as "moderately impacted" ignores all of the
evidence presented in the Phase 1 and 2 Reports that clearly indicate the effects of slag may
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confound typical SMS interpretations of bioassay and particularly bulk sediment chemistry
results. The preponderance-of-evidence approach was not designed to define "in between"
or "moderately impacted" areas (see Responses to comments on Phase 1 Report).
Consequently, Asarco has never agreed to the proposed definitions of moderately impacted
areas.
In the Proposed Plan, the only areas that receive the designation "non-impacted" are those
that do not exceed the bulk sediment chemistry Sediment Quality Standard (SQS). Asarco
has collected and reported a vast amount of information indicating that where slag particles
are present, bulk sediment chemistry is often irrelevant to the actual toxicity of the
sediments. Some sediment stations at the Asarco site were well above the SQS and showed
no other evidence by any measure of contaminant effects, yet in Section 5.2 of the Proposed
Plan these stations are defined as "minimally impacted." Because there is no evidence of
contaminant effects, it is inappropriate to define these stations as impacted in anyway.
The reason described for the minimal impact designation is that the sediments "may have
impacts in the future" However, EPA provides no scientific evidence to clarify what action
or event might reasonably be expected to cause these sediments to have impacts in the
future. There is no evidence available from any of the numerous studies completed to
support this supposition of potential future impacts. All available information, particularly
regarding slag metals availability (e.g., the sequential extraction analysis) and the present
healthy state of the benthic community, do not support this supposition. Because there is no
evidence that these sediments would reasonably pose future impacts, these sediments
should be designated as "non-impacted."
Similarly, Asarco does not agree that stations with "minor biological CSL exceedances"
should be designated as "minimally impacted." As stated in the previous comment, Asarco
believes this simplistic approach ignores the preponderance of evidence for these stations
(all the other benthic and/or bioassay measures) that indicate these stations are not
impacted in any way. These stations should also be designated as "non-impacted."
Finally, consistent with the above comments, the remediation area should be defined simply
as "impacted stations" not "severely impacted stations."
Response: A range of biological effects were identified at the various sampling locations. There are
many areas that show some impact, but not sufficient impact to warrant active remediation. It is
incorrect to ignore these "gray" areas, and only use the terms "impacted" and "non-impacted."
Therefore, EPA will continue to use the terms "moderately" and "minimally" impacted when
discussing the site sediments. The fact that the Phase 1 report did not use these terms is irrelevant,
since one of the main goals of that report was to identify areas requiring active remediation.
The goal of the preponderance of evidence approach was to assess each station using all possible data.
The goal was not to assess all stations from the "black and white" perspective as either "in" or "out"
of the cleanup area (e.g., EPA never determined that this approach would only result in two
categories of stations: impacted and non-impacted). EPA has used the information from the
preponderance of evidence approach, and has assigned a category to the range of results received from
that approach. EPA will therefore continue to use the terms "moderately impacted" and "minimally
impacted."
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Comment No. 5
Comment: 7.2 Sediment
In addition to the remedial alternatives presented in the proposed cleanup plan, additional
actions are required in the Non-Impacted/Minimally Impacted Stations and Moderately
Impacted Stations to ensure that these stations are remediated to meet all State of
Washington Criteria, (see 5.2 above)
Response: Based on the preponderance of evidence approach, the stations in the minimally impacted
and moderately impacted areas will be monitored to ensure they meet RAOs. Based on this approach,
these stations indicate some impact, but do not warrant active cleanup.
Comment No. 6
Comment: 5.2 Ecological Risk Assessment
Sediment:
Non-Impacted/Minimally Impacted Stations
Stations that have chemical concentrations greater than the state standards must be cleaned
up to meet Washington State standards. Additionally, those areas with minor biological CSL
exceedances must be remediated as well.
Moderately Impacted Stations
Stations falling within this category need to be remediated to meet Washington State
cleanup standards.
Response: As discussed above, based on the preponderance of evidence approach, the stations in the
minimally impacted and moderately impacted areas will be monitored to ensure they meet RAOs.
Based on this approach, these stations indicate some impact, but do not warrant active cleanup. As
stated in our previous responses, EPA has determined that active cleanup in these areas would have a
net negative environmental impact.
Alternatives to Sediment Capping
Comment No. 7
Comment: The proposed plan does not define the design life for the remedy. It is uncertain
how long monitoring will occur, under what conditions monitoring will be enhanced or
curtailed, and what will trigger contingency actions now and in the future. These and other
concerns lead to uncertainty regarding the permanence of the remedy and to questions
regarding how exhaustively more permanent solutions were explored.
For example, the proposal to cap the north nearshore unit is not supported by the
information and analysis. The costs shown demonstrate that dredging and upland disposal,
a more permanent remedy, is less expensive. Costs associated with mitigation for habitat
impacts due to cap design, as well as a number of additional costs - including potential
compensation for use of public aquatic lands - not included in the existing analysis, will
increase the costs associated with the capping alternative. We therefore do not support
capping of this unit.
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We also believe that permanent solutions such as treatment are viable. Vendors are
providing treatment rates of around $29 per cubic yard. We encourage EPA to further
evaluate treatment as part of the decision-making process.
Response: The caps will be designed to cover the contaminated sediments into perpetuity.
Monitoring and assessment of the caps will occur regularly as required by the Operation,
Maintenance, and Monitoring Plan (OMMP). The OMLMP will be developed by Asarco as part of the
remedial design process. The OMLMP will identify thresholds where new or revised monitoring,
maintenance, or remedial actions will be triggered.
DNR is correct that dredging with upland disposal (assuming it is placed onsite) is slightly less
expensive than capping. EPA will require that dredging be considered for this area during remedial
design. The ROD acknowledges that dredging of the Northshore area may occur in lieu of capping
depending on the outcome of remedial design evaluations.
Mitigation is not included in the cost for any alternative, because it has not been determined what
mitigation is required.
Potential treatment of marine sediments was evaluated by EPA as part of the Feasibility Study
process. Several technologies groups were evaluated including thermal destruction, thermal
desorption, chemical separation, sediment washing, and in-place solidification/stabilization. As part
of this evaluation, EPA did not identify any established treatment options for sediments that are
reliable and cost-effective.
Comment No. 8
Comment: The proposal for the sediments unit does not adequately provide for long-term
isolation of materials. For example, the porous slag slopes and incomplete armoring will
result in continued release of fine-grained slag particulates to the nearshore sediments.
More innovative alternatives to reduce the slopes to allow more effective armoring or to
isolate the peninsula in some other way need to be more thoroughly analyzed. The benefits
and total costs (including on-going source control, long-term operation and maintenance,
and contingency actions) associated with all potential alternatives need to be fully evaluated
in order to make well-informed decisions.
Response: The comment appears to be focused on the possibility of slag particles being eroded from
the slag face and deposited on the cap material or other sediments. Armoring of the slag slopes at the
shoreline was specifically addressed by the 1995 ROD for Operable Unit 02 (i.e., Asarco Tacoma
Smelter and Breakwater Peninsula ROD, which addressed upland conditions). At present, the
remedial design for the shoreline armoring system is nearly complete. The design incorporates
engineering features to minimize erosion of the slag face.
Protectiveness and Effectiveness of Sediment Capping Remedy
Comment No. 9
Comment: (Section 9.2.1) The likely static and dynamic slope stability risks indicate the
need for a more permanent solution.
Response: The stability of the sediment cap and associated perimeter side slopes will be addressed
during remedial design.
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Comment No. 10
Comment: (Section 9.2.4) What is the contingency for heavy erosion of the cap?
Response: The responsible parties will be responsible for maintaining an isolating cap at the Site.
The Operations, Maintenance, and Monitoring Plan (OMMP) will address contingency actions for
erosion of the cap (e.g., placement of additional material should a significant amount of material erode
from the cap).
Comment No. 11
Comment: Pg. 22, Sec. 8.1 Overall Protection of Human Health and the Environment,
Groundwater: There isn't any discussion of how the range of alternatives will protect the
environment of Commencement Bay, which receives the discharging groundwater. The
marine habitat of Commencement Bay is composed of the waters of Commencement Bay as
well as the sediments.
Response: Comment noted. Section 10 of the ROD addresses how the remedy for groundwater is
protective of the marine environment of Commencement Bay.
Comment No. 12
Comment: Pg. 25, Sec. 8.3, Long-Term Effectiveness and Permanence, Sediment: NOAA
agrees with the analysis in the Proposed Plan and supports the preferred approach which is
to dispose dredged contaminated sediments in the upland containment facility with other
contaminated materials. The consolidation of contaminated site materials into a few
engineered upland facilities is expected to make long-term operation, maintenance and
monitoring of these disposal facilities more efficient and reliable than would disposal into
near-shore or sub-aquatic disposal facilities.
Response: Comment noted.
Sediment Cap Thickness
Comment No. 13
Comment: EPA's Proposed Plan for the Asarco Sediments/Groundwater Operable Unit
provides for sediments to "be capped with a minimum of 1 meter of clean sediment from an
upland source." None of the information Asarco has developed during the sediment
investigations justifies the "minimum of 1 meter" thickness. Asarco is concerned that EPA
has specified a considerably thicker cap than is necessary for protection of the environment
of Commencement Bay and human health.
EPA proposes a minimum cap thickness rather than a nominal cap thickness as well as an
increase from the 0.6 m (60 cm or 2 ft) cap proposed in the Refinement of Remedy
(Parametrix, 2000) to the thicker 1 m cap. These increases represent almost twice as much
cap material as originally considered by Asarco and evaluated in the pilot cap tests. Thus,
the EPA proposal would be considerably more expensive than the Asarco proposal of a
nominal cap thickness of 0.6 m.
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No evidence has been provided by EPA that the considerably thicker cap will provide
greater protection of the environment in Commencement Bay. Requiring the minimum cap
thickness of 1 m requires technical or scientific justification that this increase would provide
a substantial increase in protection. No such justification has been provided by EPA or any
other entity in the Asarco Sediments evaluations. It appears then, that EPA's requirement
for a minimum 1 meter cap is arbitrary, capricious and beyond the scope of the agency's
authority given the persuasive evidence for a nominal 0.6 meter cap in the pilot study. Also,
under the National Contingency Plan, selected remedies are required to be cost- effective. If
a remedy is both protective of human health and the environment, and meets ARARs, it
must also be cost-effective. 40 CFR § 300.430(f)(l)(ii)(D). Under the regulation, cost-
effectiveness is determined by evaluating three criteria - long-term effectiveness and
permanence, reduction of toxicity, mobility or volume through treatment, and short-term
effectiveness. One then compares overall effectiveness with cost to see whether the cost is
proportional to effectiveness. Both a nominal 0.6 meter cap and a minimum 1 meter cap are
protective of human health and the environment and meet ARARs. However, the cost
increase attributable to the minimum 1 meter cap is disproportionate to its effectiveness
given that the nominal 0.6 meter cap is equally effective. If the remedy is not cost-effective,
EPA can't select it.
The rationale for requirement of a minimum cap thickness of 1 m appears to have its origins
in the Navy Homeport deliberations of the 1980's. At that time, deepwater disposal and
capping of Everett Harbor sediments dredged from the Homeport site was proposed.
Opponents to this action maintained that a minimum cap thickness of 1 m should be
required to eliminate any potential that the contaminated harbor sediments would be
exposed if ghost shrimp should burrow into the cap. This was based on the theory that
ghost shrimp can burrow up to nearly 1 m deep, and that their burrowing would move
sufficient quantities of contaminated sediments to the surface to incur a risk to the marine
environment.
Asarco has searched, but been unable to find factual information that supports this concern.
There appears to be a misconception that the burrowing shrimps (ghost shrimp and/or blue
mud shrimp) are a demonstrated threat to a sediment cap in Puget Sound. The potential
threat of these shrimp is that their burrowing activities will lead to sufficient contaminated
sediment redistributed to the surface layers of the cap to raise contaminant levels above
biological effects concentrations. This would require the shrimp to:
• Burrow to depths that would penetrate well into the existing sediments or
• Actively burrow within the contaminated sediments moving large volumes of the
contaminated sediment to the surface, or
• Pump large amounts of water through the contaminated sediments extracting
substantial concentrations of metals.
None of these actions are probable.
It is valuable to review what is known about the local species of burrowing shrimp. There
are two species of subtidal burrowing shrimp in Puget Sound, ghost shrimp (Neotrypaea
californiensis formerly Callianassa californiensis) and the blue mud shrimp (Upogebia
pugettensis). Neotrypaea lives primarily at middle intertidal levels, commonly decreasing in
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abundance at lower intertidal elevations due to predation (Posey 1985, Posey 1986,
Swinbanks and Luternauer 1987). Upogebia also tends to be intertidal but is found
commonly at lower elevations. Both species are also found in subtidal areas. Neotrypaea is a
deposit feeder that actively burrows in the top 10 cm of the sediments where it also
constructs a single less active extension of its burrow generally about 30 cm deep, but
sometimes as deep 40-50 cm (Swinbanks and Murray 1981). Upogebia is a filter feeder that
forms a lined burrow that remains constant over time. Its burrow is Y shaped with the lower
extension reaching as deep as 50-60 cm. Upogebia appears to actively pump water through
the U shaped upper portion of its burrow to obtain food.
To our knowledge there have been no investigations demonstrating that sufficient numbers
of ghost shrimp are likely to burrow to sufficient depths and move sufficient material to
represent any demonstrated risk to the marine environment. We believe it is more likely
that small numbers of ghost shrimp might burrow as deep as 60 cm in a cap, and that if they
did the quantity of material they would move would not raise surface concentrations of
metals to near the sediment quality standards. Upogebia does pump water through the
upper portions of its burrows to provide food and oxygen. Because its burrows are lined
and the active pumping is likely restricted to the upper U shaped portion of their burrows,
there is little reason to expect that this water flow would extract measurable levels of
contaminants even if the bottom of the burrow did extend into contaminated sediments.
Asarco has been unable to find any reports of burrowing shrimp actually changing the
contaminant concentrations of sediments within a cap, or at the surface of a cap. The
concern for contaminant redistribution appears to be theoretical rather than demonstrated.
Asarco also believes there is little risk in providing a 60-cm cap. Additional cap material can
be added at a later date if monitoring determines there is actual evidence that ghost shrimp
or other means are moving contaminants to the upper layer of the cap. The Proposed Plan
(page 31) provides for the addition of material if monitoring indicates additional material is
warranted.
Response: Based on the depth of burrowing organisms known to be present at the Asarco facility,
EPA supports the placement of a 3-foot cap at the Site. This cap thickness (3 feet or approximately
90 centimeters) is slightly different from the thickness proposed in the Proposed Plan (1 meter or
100 centimeters). As supported by the information below, EPA believes a 3-foot cap is necessary to
protect human health and the environment and to ensure long-term effectiveness and permanence,
but yet still be cost-effective. The EPA's preferred alternative is not "arbitrary and capricious and
beyond the scope of EPA's authority," as stated in the above comment. For the reasons described
below, EPA does not believe that the 0.6-meter (2-foot) cap proposed by Asarco is protective of the
environment or effective in the long term.
EPA's rationale for placing a 3-foot cap at the Site is based on the fact that bioturbation at this Site
may extend to depths of approximately 30 inches (0.75 meter). The depth of bioturbation, which is
based on the type of organisms that may inhabit the cap after cleanup, may be significant at the Site
due to the presence of Neotrypaea californiensis (formerly Callianassa californiensis). This shrimp has
been documented at the pilot cap, and tends to build extensive burrows with multiple entrances.
Burrowing activities are significant in the upper 50 centimeters (20 inches) of sediment (Hornig et al
1989, Griffis 1991, Swinbanks et al 1987, Posey 1986, and Ott et al 1976), and some research states
that burrows can extend to depths of approximately 30 inches (or 0.75 meters) (Kaestner 1980,
Hornig et al 1989). Further, both the depth of potential burrowing activity and the impact of the
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burrowing activities on sediment characteristics need to be taken into account when selecting a cap
thickness for the Site. Even if a shrimp does not penetrate the entire cap, the burrows alter the
characteristics of the sediment (higher water content, finer grained) such that the sediment may
become more prone to erosion and transport from the Site.
In addition, Callianassa are capable of redistributing a significant volume of subsurface sediment to
the surface if they colonize a cap. At the Denny Way cap in Elliott Bay, Callianassa were found at
densities of8-10/m2 at six months after capping, and between 38 - 66/m2 at 18 months after capping.
At the latter density at the Denny Way Cap, Callianassa was estimated to be redistributing 1.2 to
5.4 kg/m2/day of subsurface sediment to the cap surface. Further, as indicated by the results of the
pilot cap study conducted at the Site, a few inches of mixing occurs within the bottom of the clean cap
material during cap placement. To insure an effective cap, these local data (regarding the volume of
sediment moved by organisms and the amount of mixing that occurs during cap placement) indicate
that a minimum cap thickness of 3 feet is appropriate to minimize disturbance and recycling of the
contaminated sediments to the surface.
In conclusion, since the presence of these burrowing organisms has been documented at the Site, and
there is evidence to indicate these organisms burrow to approximately 30 inches, EPA supports a
minimum 3-foot (36 inch) cap. A cap of this thickness would provide the long-term isolation that is
necessary for this remedial action.
Further, the Refinement of Remedy Report (Hydrometrics, January 2000) proposed a minimum cap
thickness of 2 feet, not a nominal thickness of 0.6 meter (or approximately 2 feet), as stated in the
comment. EPA is currently proposing a cap with a minimum thickness of 3 feet. This difference in
cap thickness does not represent twice the volume of material as stated in the comment.
Comment No. 14
Comment: (Section 8.1) Were the full range of potential organisms considered when
determining the thickness of cap necessary to prevent recontamination due to bioturbation?
Response: Yes. See the response (above) to Comment No. 13.
Comment No. 15
Comment: Pg. 29, Sec. 9.2.1 In Situ Sediment Capping: [As stated in the Proposed Plan] "In
situ capping is the Preferred Alternative for the Nearshore/Offshore area and Northshore
area. Approximately 88,000 sq. yd. (18 acres) of existing contaminated sediments in the
Nearshore/Offshore area will be capped with a minimum of 1 meter of clean sediment from
an upland source and approximately 7,000 sq. yd. (1.5 acres) of existing contaminated
sediments in the Northshore area will be capped with a minimum of 1 meter of clean
sediment. The cap thickness will be designed such that it provides chemical isolation, is
stable, and provides a cap surface that will allow recolonization of benthic communities."
While NOAA was originally pessimistic about the feasibility of capping the contaminated
sediments in the remaining Nearshore and Offshore Units, the initial results of the Pilot
Project supports this approach. Obviously, a fairly coarse material (sand and gravel) will be
needed; such materials are often low in organic content (usually in the silt and clay
fractions). However, it would be desirable if there is some way that increased organic
content could be incorporated into the capping material to enhance biological repopulation.
This is a challenge since the organics are usually associated with the finer components
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which can be swept away by the currents during emplacement. EPA should keep the goal of
benthic recolonization in mind during design.
NOAA believes that nothing less than a 1-meter cap will effectively isolate contaminated
sediment at the ASARCO site. One of the objectives for the sediment component of the
remedy is "Restore and preserve aquatic habitats by limiting and/or preventing the
exposure of environmental receptors to sediments with contaminants above Washington
State Sediment Management Standards (SMS, WAC 173-204)" (See bottom of pg. 16). In
order to accomplish this goal, the habitat value of the sediments must be restored. It is likely
that burrowing organisms will recolonize the cap material soon after it is placed, as
occurred in the pilot study cap at the site (see the monitoring reports prepared for Asarco by
Parametrix, Inc.). One organism thought to inhabit the sediment offshore of the Asarco
facility is a ghost shrimp (also called mud shrimp). This organism is known to construct
burrows 2 feet deep (Carman, personal communication). Other researchers report that ghost
shrimp burrow to a depth of three feet (Ricketts and Calvin, 1962). Based on this
information, we conclude that one meter is the minimum cap thickness that would be
effective. It is necessary to isolate contaminated sediment from ghost shrimp and other
burrowing organisms to prevent the biota from facilitating transfer of the contaminants to
the sediment surface, the water column, and to higher trophic level organisms (G. F. Riedel
et. al., 1989).
Response: EPA concurs with NOAA's comment. Benthic recolonization will be considered during
design of the cap, and EPA continues to support a 3-foot-thick cap for the Site.
Sediment Dredging
Comment No. 16
Comment: The Proposed Plan describes dredging to a depth of approximately 2 feet. This is
an acceptable depth to use to develop a conservative estimate of dredging volume.
However, it needs to be made clear that actual dredging depth will depend on the actual
depth of contamination that is verified to be present during Remedial Design and during
actual dredging. There is no evidence of sediments exceeding cleanup screening levels
(CSLs) below a depth of 1 ft in the marina.
As part of the Phase 2 Expanded RI/FS, subsurface sediment chemistry core samples were
collected by divers at stations 5-0 and 5.5-0 in the yacht basin (Parametrix 1996). The upper
layer of sediment that contains metals higher than CSLs was visually distinctive from the
deeper sediments that did not exceed CSLs. Cores were observed to contain black sand in
the upper 0.4 ft and gray sand from 0.4 to 1.9 ft. Core samples from the upper 1.0 ft
exceeded CSLs for arsenic, copper, and zinc. Samples from 1.0 to 1.9 ft were below CSLs.
Divers collected two additional core samples from the shallow, shoreward side of the basin
in 1997. Rather than dividing the cores into 1-ft segments, these cores were sectioned
according to visually distinctive changes in sediment type. The core from station 5-0.9 was
described as a dark olive colored sandy gravel in the upper 17 cm (0.6 ft). The 17 to 18 cm
section was gravel with shell debris. Copper exceeded the CSL in the upper section and all
metals tested were below CSLs in the 17 to 18 cm section. The other core sample contained
olive colored fine sand in the upper 21 cm (0.7 ft). The 21 to 37.5 cm section (0.7 to 1.2 ft) was
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silty sand with gravel and cobbles. The upper section exceeded CSLs for copper and
mercury and the lower section was less than the CSLs for all metals analyzed.
Additional core samples will be collected in the spring of 2000 as part of the preliminary
design analyses for yacht basin dredging. These analyses will help determine whether
metals exceeding CSLs are limited to the upper 1 ft of sediments, or if deeper sediments
exceed CSLs in any areas of the yacht basin.
Response: EPA acknowledges Asarco's comment. The exact depth of dredging will depend on the
existing core information, as well as the core information that will be collected in the spring of2000.
Post-dredging confirmatory sampling will also be required to confirm adequate removal of
contaminated sediments.
Comment No. 17
Comment: Page 20, Table 7-3. The note for alternative S-2D states: "As a contingency, if all
the contaminated material cannot be removed from the Yacht Basin, dredging in the Basin
followed by placement of clean material may occur." EPA should acknowledge that slag
will remain in the Yacht Basin following dredging and that this material, though it may
exceed CSLs, has been shown to not exhibit contaminant effects at other areas of the Site. It
would not be possible to remove all the slag exceeding CSLs from the basin without
removing the entire breakwater peninsula, and dredging at the base of the peninsula will
need to be designed so that it does not destabilize steep slopes. Placement of clean material
over the slag will not be necessary because the metals in slag are bound in a rock-like form
and are not necessarily available to the benthic community.
Response: EPA will depend on a tiered sampling approach for determining if additional action in the
Yacht Basin is necessary after initial dredging is complete. As discussed in Asarco's comment above,
it is anticipated that the sediment below 1 to 2 feet in the Yacht Basin does not contain chemical
concentrations above state Sediment Quality Standards (however, an exception may be immediately
next to the Breakwater Peninsula). Should conditions warrant, however, EPA may require placement
of a cap over a dredged surface as one possible option for remediating parts of the Yacht Basin.
Contingencies for addressing these types of situations will be developed during the remedial design.
Comment No. 18
Comment: EPA + Asarco should consider deeper dredging between the road and a dock to
remove contaminants and to facilitate passage of deeper draught Boats - contaminated
sediments have accumulate from Asarco property to fill this area in to a disadvantageous
degree.
Response: EPA's goal is to dredge the sediment where samples indicate adverse biological effects. The
exact depth of dredging will be further refined in late 2000, after additional sampling has occurred in
the Yacht Basin. As for dredging to accommodate passage of deeper draught boats, Asarco has
committed to work directly with Tacoma Yacht Club members on this issue. This collaborative effort
will ensure the needs of boat owners are being addressed.
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Comment No. 19
Comment: Make sure any Dredging Plan for the Yacht Basin includes indemnification for
damage to Boats + houses and dockage. Make sure provision for temporary moorage for
displaced boats is made available.
Response: It is EPA's understanding that Asarco will work directly with the Yacht Basin owners on
indemnification and temporary moorage issues.
Comment No. 20
Comment: Pg. 30, Sec. 9.2.2 Yacht Basin: [As stated in the Proposed Plan] "For the dredging
alternative, the material would be dewatered, and then placed in a controlled, upland
location (known as Crescent Park, in the central part of the upland Facility), that will be
monitored for many years. This allows for the long-term effectiveness of the remedy to be
monitored. Further, the mobility of the contaminants would be reduced, as the sediment
would be in a location that does not have contact with water. There will also be contingency
plans should the upland cap begin to fail (i.e., get cracks in it)."
Comment: NOAA supports the preferred alternative because it permanently removes
contamination from a site area that is perturbed by marina activities and only dredging to
remove the contamination will allow the marina to continue operations in the future
without restrictions on dredging. In addition, isolating the contaminated materials in an
upland facility with contingencies for any incipient failure of the containment structure
should be easy to monitor and implement because these upland site areas also will be used
for isolation of contaminated soils and/or debris.
Response: EPA acknowledges NOAA's support for the proposed remedies.
Comment No. 21
Comment: (Oral comment provided at the February 10, 2000 public meeting)
Well, I have a voice that doesn't need a microphone. I would like to once again address the
materials that have come down on the site close to the shore both inside of the breakwater
and along our A dock, the part down there.
Those sediments have come down and the glacial till has come down with sediments
because it's been blessed with those for decades as well. It has caused us a problem that will
be a problem with our agreement with the park board. We lease this property from the park
board.
And when this project as totally dreamed up comes to pass that there is a walkway, a
pedestrian walkway along there, we have unattractive boathouses on that side so that you
can see them from that walkway. And the reason for that is that it is shallow there.
This land that has come down has made the water shallow so larger boats, larger sailboats
cannot come in there. Only small boats, inexpensive boats, can go in there because they're
capable of backing out and turning around in a normal tide, where a larger boat can't do it
because it's too shallow there.
So we have, one, the problem that, I think, that the sediments must be deeper there because
it's been built up over a period of time and not sluiced away. But we also have the problem
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of that material coming down in a way that makes it so that we need that dredged out, that
material removed for other reasons, and material that we had nothing to do with depositing
there as well as however much arsenic there is.
And we would like to see what kind of help we could get in looking deeper into that
particular problem when you consider the depth of the dredging or the amount of the
dredging that you are going to do. Thank you.
Response: Comment noted. EPA will take steps to see that Asarco coordinates with the Tacoma
Yacht Club to address the coordination of dredging required for environmental protection and
possible additional dredging that may be advantageous for navigation or other purposes.
Comment No. 22
Comment: (Oral comment provided at the February 10, 2000 public meeting)
Thank you.
Again, as chairman 9f the board of trustees of Tacoma Yacht Club, I would like to officially
put in the record that we want to be included as members of the team that work on
planning and designing the way that we would go about dredging. At least being included
because of the 300-plus boats our membership has moored here plus the portion of the basin
that we lease to a private operator for public moorings. There's another 200-plus boats.
We have a lot of responsibility there, and we don't want to turn that responsibility over
without having a say in just exactly how it's going to take place. So we want to officially go
on the record as making that request.
We will make the people available. We will make professional people available, and I think
probably will be an asset to the team. Bottom line is, we'd like you to leave it alone but I got
a hunch you're probably not interested in that so we would want to be involved.
Response: Comment noted. EPA will take steps to see that the responsible parties coordinate with the
Tacoma Yacht Club regarding the dredging and associated work that will occur in the Yacht Basin.
Comment No. 23
Comment: (Oral comment provided at the February 10, 2000 public meeting)
Thank you. I'm Chuck Prowse of the Tacoma Yacht Club, and Roy Brooks pretty well
summed up everything that I wanted to say. I have some concerns about details and that
was primarily the closure of the basin and its impact on our use of boats, being able to move
them out of the basin when we want to use them.
Also I'd like to make a comment on a subject that was mentioned earlier and that was
controlling sediments generated during the dredging operation and the proximity of this
basin to the Metro Parks aquarium. There is a tidal current that runs parallel to the shoreline
here and it runs up to two knots. It runs right past our clubhouse and goes right on down to
the aquarium. It would take any sediment that escaped out of the basin right down to 5 the
aquarium intake.
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Response: Comment noted. Suspended sediment caused by dredging will be controlled. The details
will be addressed during the remedial design.
Institutional Concerns Regarding Sediment Capping
Comment No. 24
Comment: The current proposal includes the permanent capping of contaminated
sediments in place. Siting such permanent caps within the City of Tacoma Harbor Area - as
the proposal currently does - is problematic in that the caps may be inconsistent with
constitutional, statutory and regulatory directives.
The main issues are:
• Capping as a mechanism for contaminated sediment storage is a non water-dependent
use. Non water-dependent uses in harbor areas are considered interim uses and can only
be allowed if defined criteria are met (e.g., compatibility and exceptional circumstance
analyses and other factors, Washington Administrative Code (WAC) 332-30-137);
• Institutional controls (i.e., Regulated Navigation Area) likely necessary to maintain the
integrity of the capped areas will limit commerce and navigation in a Harbor Area.
However, Harbor Areas are reserved for commerce and navigation in the Washington
State Constitution; and
• Caps displace navigation and increase present navigational hazards.
In addition, some of the proposed cap appears to extend beyond the outer harbor line. This
is especially problematic because Article XV Section 1 of the Washington State Constitution
establishes that "the state shall never give, sell, or lease to any private person, corporation,
or association any rights whatever in the waters beyond such harbor lines."
If the proposed caps are authorized, the City of Tacoma's Harbor Area will have to be
adjusted, a time-consuming process subject to rules detailed in WAC 332-30-116. A Harbor
Area relocation should maintain or enhance the type and amount of harbor area needed to
meet long-term needs of water dependent commerce. The relocation should also maintain
adequate space for navigation beyond the outer harbor line. After these findings are made,
there are other issues to be considered (see WAC 332-30-116(2)).
We have identified to EPA the value of the Asarco area as an important functional
component to the overall Harbor Area in Commencement Bay. We continue to encourage
EPA to define a plan that recognizes this important land use role and that allows a balance
between commerce/navigation and habitat functional needs. The cleanup plan should not
impact the existing deep draft capability at the site or lessen the current and future capacity
for structures associated with navigation and commerce.
Response: EPA offers a six part response:
1. Capping as a Mechanism for Contaminated Sediment Storage is a Non Water-Dependent Use -
EPA does not intend capping as a temporary or interim remedy. EPA is mandated by CERCLA
to select the remedies that are permanent to the maximum extend practicable. EPA must also
perform five-year reviews to ensure that the cap stays in place and remains protective. EPA will
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require the cap to be monitored to ensure that it is continuing to protect human health and the
environment. If EPA determines that the cap is no longer protective, EPA can amend its ROD or
issue an Explanation of Significant Difference (ESD) and modify the remedy if necessary.
EPA also disagrees that capping is a nonwater-dependent use. The regulations define " nonwater-
dependent use" as a "use that can operate in a location other than on the waterfront
WAC 332-30-106(42). First, if EPA selects capping as the appropriate remedy then it must take
place in the water; that is, it cannot logically exist in any location but on the water, thereby
making it water dependent as defined by the regulations. WAC 332-30-106(71). Second,
Washington's regulations also define the policy for "nonwater-dependent use" as a "low priority
use providing minimum public benefits." WAC 332-30-137. Capping the sediments to prevent
harm to human health and the environment does provide "public benefits" and therefore does not
fall under the regulatory policy.
2. Institutional Controls - Although EPA must implement institutional controls to maintain the
integrity of the cap, EPA does not believe that capping will impede reasonably foreseeable uses of
navigation and commerce.
3. Caps Displace Navigation and Increase Present Navigational Hazards - See response to #2,
above.
4. The Proposed Cap Appears to Extend Beyond the Outer Harbor Line - EPA is not seeking to
buy, lease, or receive rights to property. By choosing capping as a remedy, EPA is trying to
prevent further contamination of the sediments. EPA, or the party performing the work, will need
access to the waters to perform the remediation and subsequent monitoring, but the property shall
remain with DNR.
5. Adjustment of the City ofTacoma's Harbor Area - EPA expects that DNR will cooperate in
making any necessary and appropriate changes to legal designations and in developing
institutional controls to maintain the protectiveness of the remedy so that human health and the
environment can be protected.
6. Deep Draft Capability of the Site and Future Capacity for Structures Associated With
Navigation and Commerce - See response to #2, above.
Comment No. 25
Comment: For public aquatic lands, the state laws, the state Constitution, and the existing
policies, strategies, and guidance for implementing these laws do not support the use of
public aquatic lands for permanent storage of contaminated material. If contamination is to
be temporarily stored on public aquatic lands, the worst of the contamination must be
removed for treatment or upland disposal, and the remaining storage site must be designed
to allow future removal for treatment or upland disposal once technology makes it feasible
to do so. Neither the alternatives analysis nor the resulting proposal to cap recognizes or
incorporates these standards for use of public aquatic lands.
Response: The laws and policies cited by DNR do not clearly address cleanup issues, including the
suitability of capping as a remedy. EPA intends for capping to be a permanent solution for the
sediments. EPA will require monitoring of the cap to ensure its stability and effectiveness. If EPA
later determines that the cap is not protecting human health and the environment, EPA can amend
its ROD or issue an Explanation of Significant Difference (ESD) to modify the remedy.
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Groundwater Extraction and Treatment
Comment No. 26
Comment: We strongly support alternatives to actively remove and treat contaminated
groundwater, and we encourage a commitment to long-term, intensive monitoring to
determine effectiveness of the remedy.
Response: Alternative GW-C (Pump/Treat and Discharge to Outfalls) was evaluated as part of the
Feasibility Study. The pump/treat system would need to be operated into perpetuity because the
primary source material (slag) can not be removed and will continue to contribute contaminants to
groundwater indefinitely. A pump/treat system such as Alternative GW-C would therefore not
provide any permanent environmental solution. In addition to being cost-effective, the preferred
alternative (GW-B) has the benefit of reducing groundwater discharge to Commencement Bay by an
estimated 75 to 95 percent, thus resulting in a significant reduction in contaminant loading to the
marine environment.
Comment No. 27
(Section 8.6) Since the following sentence claims that pump and treat is reliable and
available, by "difficult" do you mean costly?
Response: The pump and treat alternative would be "difficult" to construct and operate in the sense
that the layout of the overall system would be extensive and the physical plant facilities large
compared to similar systems at other sites. From a hydraulic perspective, a pump and treat system
would be inefficient due to the proximity of Commencement Bay (i.e., an extraction system would
pump a significant volume of water originating from the bay). From a logistical standpoint, the size
and extent of the system would be relatively difficult to operate given the presence of the other remedy
elements (low-permeability cap, drainage systems, onsite containment facility, etc.) and the other site
uses anticipated for the future. The system would also be costly to build and operate compared to the
other alternatives evaluated.
Remediation Goals/Levels (Groundwater)
Comment No. 28
Comment: Asarco strongly prefers that the Preferred Alternative and Proposed Plan result
in attainment of Remedial Action Objectives and Remediation Goals (RGs). Asarco's
primary concerns regarding the attainment of RAOs and RGs are:
1. The Remedial Action Objectives for groundwater do not match the RAOs of the Asarco
Tacoma Smelter Facility Record of Decision ("Upland") ROD. Since the remedial action
is being, and will continue to be, implemented as part of the Upland ROD, it appears
that the remedial action must "serve two masters."
2. RAOs are overly broad and ignore site-specific information about the risk from arsenic.
3. The compliance point for attainment of RGs is not specified. Depending on location of
groundwater compliance points the RGs may not be attainable.
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To remedy these concerns, Asarco proposes that:
• The RAOs for groundwater in the Proposed Plan should complement the RAOs for
groundwater in the Upland ROD;
• The RG for arsenic should be based on EPA's Site-specific risk assessment that indicates
existing groundwater discharges to Commencement Bay do not cause unacceptable risks
to human health and the environment; and
• the compliance point for groundwater discharges should be identified as the point of
discharge (i.e., post-remedial action groundwater/seawater interface).
Specifically, Asarco proposes the following groundwater RAOs:
1. Prevent ingestion of potable groundwater containing concentrations above Federal
MCLs and direct contact with groundwater containing contaminants in concentrations
above risk-based goals.
2. Reduce discharge to Commencement Bay of groundwater that exceeds applicable
marine surface water quality standards, risk-based levels protective of human health, or
background concentrations (if background concentrations are higher than the
standards).
Asarco proposes an arsenic remediation goal of 0.012 mg/L based on maintenance or
improvement of groundwater arsenic concentration at the slag shoreline.
Asarco proposes a compliance point of surface water along the face of the post-RA slag
shoreline.
Remedial Action Objectives
The Proposed Plan modifies the earlier RAOs in the Upland ROD for the Site making them
overly broad and inappropriate. EPA's remedial action objectives (RAOs) for groundwater
in the Proposed Plan are as follows:
1. Prevent ingestion of or direct contact with groundwater containing contaminants.
2. Prevent discharge (to Commencement Bay) of groundwater that exceeds applicable
marine surface water quality standards or background concentrations (if background
concentrations are higher than the standards).
For comparison, the Upland ROD RAOs are:
1. Prevent ingestion of potable (Class IIB) groundwater containing contaminants in
concentrations above ARARs or above risk-based goals when ARARs are not protective
or not available.
2. Reduce discharge to Commencement Bay of contaminated waters containing
contaminants in concentrations above ARARs or risk-based goals when ARARs are not
protective or not available.
As written, Proposed Plan RAO #1 is neither achievable nor necessary. EPA has substituted
"groundwater" for "potable groundwater" and "groundwater containing contaminants" for
"groundwater containing concentrations above ARARs" All groundwater, everywhere,
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contains "contaminants" but that is not a problem for human health or aquatic life unless
concentrations are too high (i.e., above ARARs or risk-based goals). As written the RAO is
so broad that it is nearly meaningless and gives no direction to the goals that are to be
achieved.
Compared to the Upland ROD RAOs, Proposed Plan RAO #2:
• Substitutes "prevent discharge to Commencement Bay of groundwater" for "reduce
discharge of contaminated water"; and
• Substitutes "background concentrations" for the phrase "risk-based goals when ARARs
are not protective or not available."
Prevention of discharge of groundwater from the Site is not technically possible. However,
the Preferred Alternative will reduce the discharge of groundwater from the Site to the
extent practicable and will reduce the discharge of contaminants to levels that are clearly
protective of human health and the environment.
Background concentrations are not appropriate substitutes for risk-based goals for arsenic
since Site-specific risk information and protective risk-based goals are available. The
Proposed Plan correctly points out that
"Neither the Maximum Contaminant Limits (MCLs) promulgated under the
Federal Clean Water Act nor the State of Washington Model Toxics Cleanup
Act (MTCA) groundwater cleanup levels are considered Applicable or
Relevant and Appropriate Requirements (ARARs) for the shallow
groundwater system at the Facility." page 15, Proposed Plan
In this case, it is appropriate to use risk-based levels and EPA correctly notes that:
"Currently, the groundwater discharging to Commencement Bay will exceed
human health risk based levels for fish consumption (0.14 jjg/ L for arsenic)
(National Toxics Rule; CFR 40, § 131.36). However, past fish tissue sampling
indicates low risk from Facility contaminants even to people consuming large
quantities of fish from the Facility." page 15, Proposed Plan
However, the RAO and RG for arsenic fail to acknowledge EPA's uncertainty in the
National Toxics Rule (NTR) fish consumption limit and fails to acknowledge EPA's Site-
specific data and risk assessment. The NTR does not reflect the current understanding of
arsenic health risks. EPA has been reviewing the NTR arsenic criteria for several years with
the intent to revise the criteria. EPA's risk assessment indicates that existing risk from fish
consumption is acceptable and will be lowered further by implementation of the Preferred
alternative.
CERCLA Section 121(d) (2) (B)(i) provides a standard for determining whether or not any
water quality criteria under the Clean Water Act is relevant and appropriate. In making this
determination, Section 121 directs that the Agency:
"shall consider the designated or potential use of the surface or groundwater, the
environmental media affected, the purposes for which such criteria were developed, and the
latest information available."
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The existing human health criteria for arsenic in the NTR does not reflect the latest
information available and does not consider Commencement Bay, the environmental media
affected. EPA is currently in the process of revising the human health criteria for arsenic in
the NTR. Recent information on arsenic risks in Commencement Bay are available in EPA's
risk assessment entitled "EPA Ecological Risk Assessment and Seafood Consumption
Screening Risk Assessment Asarco Sediment Site - October 1996." Given the uncertainty in
the NTR arsenic level and the existence of more recent Site-specific data, Asarco believes
that the NTR arsenic level should not be an ARAR for the Site in accordance with CERCLA
Section 121(d)(2)(B)(i). In establishing the RAO for arsenic in groundwater, EPA should
consider the latest information on the environmental media affected. The latest information
available is EPA's risk assessment on Commencement Bay. Asarco proposes that the RAO
be revised to include the use of risk-based limits for arsenic.
Remediation Goal for Arsenic in Groundwater
For current arsenic risks EPA's risk assessment (USEPA, October 1996) concluded:
The potential for adverse non-cancer health effects associated with ingestion of fish caught
near the site is low (i.e. at or below the hazard quotient benchmark value of 1.0).
For the reasonable maximally exposed individual, inorganic cancer risk estimates are close
to but not greater than the upper end of the risk management range recommended in the
NCP (1 x 10-6 to 1 x 10-4) at fish ingestion rates greater than approximately 150 grams per
day.
For the average case individual, inorganic cancer risk estimates are within or below the NCP
risk management range at all fish ingestion rates considered.
Or as summarized by EPA in the Proposed Plan:
. .past fish tissue sampling indicates low risk from Facility contaminants
even to people consuming large quantities of fish from the Facility." Page 15,
Proposed Plan
In light of Site-specific data regarding the low arsenic risk from seafood ingestion, Asarco
proposes that an appropriate RG for arsenic would be based on maintaining existing arsenic
concentrations in groundwater discharging to Commencement Bay. Since the Preferred
Alternative will result in a substantial decrease (to the extent practicable) in the amount of
groundwater flow to Commencement Bay, maintaining groundwater arsenic concentrations
would result in substantial decreases in the load (or mass) of arsenic discharged to
Commencement Bay. Therefore, the Proposed Remedy with Asarco's proposed RG would
result in further reduction to the maximum extent practicable of the already acceptable
arsenic risk.
Groundwater Compliance Point
The Proposed Plan does not specify a compliance point for groundwater discharging to
Commencement Bay. Asarco proposes that the compliance point for groundwater
discharges should be in the surface water as close as technically possible to the point or
points where ground water flows into the surface water. After remediation, the point on the
Site that is "as close as technically possible to the point or points where the ground water
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flows into the surface water" will be surface water along the face of the stabilized and
protected slag shoreline. This compliance point of surface water along the face of the post-
RA slag shoreline would protect the water resource at the point of possible human or
aquatic life exposure and would comply with MTCA.
Under Washington's Model Toxics Control Act (MTCA), groundwater compliance
monitoring points should be selected to be "as close as technically possible to the point or
points where the ground water flows into the surface water." (WAC 173-340-720(3)(b)(v)).
Furthermore, "At these sites [where the affected ground water flows into nearby surface
water], the department may approve a conditional point of compliance that is located
within the surface water as." (WAC 173-340-720(6)(d)). Presently, the point where
groundwater flows into surface water on the Site is the face of the slag shoreline. During
Upland remediation, the face of the slag shoreline will be armored to prevent erosion. After
Upland remediation is completed, the point where groundwater flows into surface water on
the Site will be the face of the armored shoreline. Therefore, the proposed groundwater
compliance point is surface water at the face of the post-RA shoreline.
Response: The response to the above comment is been divided into three parts:
• Remedial Action Objectives for Groundwater
• Cleanup (Remediation) Goal for Arsenic in Groundwater
• Point of Compliance for Groundwater
1) Remedial Action Objectives for Groundwater
The comment suggests that the RAOsfor groundwater must replicate the RAOs cited in the 1995
ROD for OU 02 (i.e., the "serve two masters" argument). The 1995 ROD specifically defers a
cleanup decision for Facility groundwater. Because the remedy selection for groundwater was
deferred for 5 years, it is appropriate to reassess the RAOs in context of new information that has
become available.
EPA agrees with Asarco's comment indicating that the RAO as presented in the Proposed Plan may
be vague with respect to the use of the term "contaminated" without qualification. Therefore, the
RAO as stated in Section 8 of this ROD has been revised to read:
"Prevent ingestion of groundwater containing contaminant concentrations above
federal maximum contaminant levels (MCLs) or above risk-based goals for those
substances for which MCLs have not been established and prevent direct contact with
groundwater containing contaminant concentrations above applicable risk-based
goals."
Regarding the second RAO ("Prevent discharge [to Commencement Bay] of groundwater that
exceeds applicable marine surface water quality standards or background concentrations [if
background concentrations are higher than the standards]."): The RAO is not meant to suggest that
discharge of all groundwater to Commencement Bay can be prevented. Instead, the intended objective
is to prevent discharge of groundwater containing contaminants at concentrations in excess of
applicable standards or background concentrations. We agree with Asarco's proposed revision of the
RAO that recognizes the need to incorporate wording acknowledging the need to protect human
health in addition to the marine environment. Therefore, the RAO as stated in the ROD has been
revised to read:
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"Prevent discharge to Commencement Bay of groundwater containing contaminants
at concentrations exceeding applicable marine surface water quality standards, risk-
based levels protective of human health, or background concentrations (if background
concentrations are higher than the applicable standards)."
2) Cleanup (Remediation) Level for Arsenic in Groundwater
EPA acknowledges that human health criteria for arsenic is under review. At this writing, however,
the National Toxics Rule (NTR) standard of 0.14 ug/L has not been revised and remains an ARAR
for the Site. However, the ROD waives the NTR standard for groundwater and defers to MTCAfor
determining the cleanup level. Application ofMTCA results in a cleanup level of 6 ng/Lfor arsenic
(see Section 12.1.3 of the ROD).
3) Point o f Compliance for Groundwater
The point of compliance for groundwater was recently determined by EPA in cooperation with the
Washington State Department of Ecology. The point of compliance will be at the interface of the
surface water and the shoreline of Commencement Bay and the Yacht Basin. Specifically, the point of
compliance for the slag aquifer will be at the interface between the slag (or any overlying shoreline
armoring materials) and the surface water. This is technically a "conditional" point of compliance as
addressed by WAC 173-340-720 (6)(c) and (d). Compliance will be based on a comparison of
groundwater data from nearshore monitoring wells with cleanup levels adjusted to reflect a location-
specific dilution/attenuation factor. See Section 12.1.4 of the ROD for more information.
Comment No. 29
Comment: Page 15, Remediation Goals. At a minimum it would seem appropriate for EPA
to acknowledge that the NTR arsenic criteria is under revision. It might also be appropriate
to establish that if the arsenic RG can not be met, then the revised arsenic criteria would be
considered in determining the need for additional groundwater controls/remediation.
Response: See the response to Comment No. 28. The ROD acknowledges the on-going review of risk
information for arsenic. Improvements in groundwater quality are not expected to occur immediately
after remediation is complete. Instead, such improvements are likely to occur over a period of years.
To that end, EPA expects that remedy success or failure with respect to meeting cleanup levels can
only be determined after collecting post-remediation data for several years. If the cleanup level for
arsenic is not being met, the need for supplementary cleanup actions will be assessed as part of the
five year review processes. Such actions could include, but are not limited to, relaxation of the
cleanup level (if supported by new risk-based standards) or additional remedial actions if they are
deemed effective and practicable. EPA expects that the Operation, Maintenance, and Monitoring
Plan (OMMP) will identify an evaluation and decision process for assessing the long-term
monitoring data and determining if the cleanup levels are being achieved.
Comment No. 30
Comment: 6.1 Groundwater Cleanup Objectives
Background contamination levels for copper in the remedial area are held to be 40 ug/L and
a question is raised as to whether groundwater cleanup levels of 3.1 ug/L can be met.
However, no mention is made as to what the background levels for copper in groundwater
are for the Commencement Bay area outside of the Asarco site. Presumably, the higher
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copper background contaminant level is directly attributable to past smelter operations, and
therefore subject to remedial action to correct the problem.
Response: The 40 ug/L concentration cited for copper is the established "natural" background level.
It represents the copper concentration in groundwater in the greater Tacoma area, not just in the
vicinity of the Site (for further information on how background levels were determined see Remedial
Action Objectives and Preliminary Remediation Goals for the Asarco Tacoma Site, Appendix F,
[EPA, April 1993]).
Comment No. 31
Comment: (Section 6.1) What happens in the future if and when background concentrations
and laboratory detection limits drop? Will cleanup goals track these drops, if they occur,
until it reaches the National Toxics Rule standard of 0.14 jj.g/1 for arsenic. Likewise for
copper.
Response: The five-year review process will assess if the remedy is performing as designed and is still
protective of human health and the environment. Cleanup levels could be modified to reflect new risk-
based or regulatory criteria.
Comment No. 32
Comment: Pg. 15, Sec 6.1, Groundwater Cleanup Objectives: [As stated in the Proposed Plan]
• "Prevent discharge (to Commencement Bay) of groundwater that exceeds applicable
marine surface water quality standards or background concentrations (if background
concentrations are higher than the standards)."
AND: "The cleanup goal of 3.1 ug/L for copper is protective of human health and marine
life in Commencement Bay. It is acknowledged, however, that the background
concentration for copper in the vicinity of the Facility is 40 ug/L , and it may not be possible
to achieve the 3.1 ug/L cleanup goal. If not, copper in groundwater will be managed to the
40 ug/L background concentration."
These statements are ambiguous. The information provided above documents that the
(upgradient groundwater) background concentration for copper is higher than the acute
and chronic ambient water quality criteria. On the basis of the wording of the Groundwater
Cleanup Objective, this would indicate that for copper in groundwater the cleanup objective
is 40 ug/L. However, the ecologic receptors and the applicable criterion apply to waters of
Commencement Bay. It is questionable whether a remedy that does not lead to compliance
with the water quality criteria is ecologically protective, and it is possible that even if the
groundwater copper concentration is controlled to 40 ug/L, that the shoreline waters of
Commencement Bay will not meet the water standard. There are other sources of copper
(and other metals and metalloids) contamination along the shoreline such as contaminated
surface water runoff and the large deposits of slag, but these sources also are affected by
former actions of Asarco.
It is the position of NOAA, as the federal Natural Resource Trustee for marine organisms
and habitats, that a goal of the overall remedy should be the attainment of water quality
criteria for the protection of marine life in all areas of Commencement Bay affected by
former site smelting, manufacturing, and/or disposal activities.
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Response: Comment noted. EPA shares the Natural Resource Trustee's goal to attain water quality
criteria for the protection of marine life in Commencement Bay. This is reflected in the stated cleanup
level of 3.1 ng/Lfor copper (equal to the marine chronic criteria for copper). EPA believes that the 3.1
Hg/L cleanup level for copper may be achieved before groundwater discharges to Commencement Bay.
EPA expects copper concentrations to decline with time due to the benefits of upland contaminant
source removal actions, site capping and surface water controls (limiting groundwater recharge), and
the ongoing seawater intrusion that occurs in the nearshore portions of the site aquifers (resulting in
dilution of copper before groundwater is discharged to Commencement Bay). "Ultra clean" sampling
data collected by Asarco in 1999 show that current (pre-RA) copper concentrations in
Commencement Bay water immediately adjacent to the slag shoreline face are below the 3.1 ng/L
cleanup level in most locations sampled. The significant exception is the Yacht Basin where samples
exceed the copper cleanup level as far as 200feet from shore (8.38 ng/L, average of high and low tide
samples collected in September 1999). This is not unexpected given the proximity of the Yacht Basin
to the previously existing "Copper Refinery Area," a significant upland source of copper
contamination. Source materials are being removed from the Copper Refinery Area as part of the
OU 02 remedial action. Further, Yacht Basin sediments containing copper above sediment cleanup
levels will be removed by dredging as part of the remedial action for OU 06. With time, these source
removal efforts and other upland remedial actions are expected to result in decreased copper
concentrations in the Yacht Basin water.
Remediation Goals/Levels (Sediment)
Comment No. 33
Comment: The Proposed Plan describes the sediment clean up objectives for remediation as
the State Sediment Management Standards (SMS). Asarco agrees that the SMS may be a
useful relatively simple initial measure that can be used as a guideline of the success of the
remediation. However, it should not be the sole determination of whether the remediation is
successful as defined in Section 6.2 of the Proposed Plan.
As discussed above, the SMS uses bulk sediment chemistry, bioassays, and relatively
simplistic measures of benthic abundance. Both the data analysis presented in the Phase 1
Report and EPA's own methodology for determining contaminant effects areas presented in
the draft Proposed Plan go beyond the simple SMS approach. It is therefore unreasonable to
go back to the SMS approach when evaluating the success of remediation.
If the physical and chemical properties of the sediments (e.g., particularly slag particles) can
confound the determination of cleanup areas, they can certainly confound the determination
of cleanup success. To be consistent with all of the knowledge gained on Asarco sediments
over the years, an achievable reasonable sediment cleanup objective must allow for these
potentially confounding effects and go beyond a simple SMS type approach.
Asarco recommends that a preponderance of evidence approach as presented in the Phase 1
Report be used to determine the cleanup success. Because this approach may require
extensive sampling and data analysis, cleanup success could be determined through a tiered
process. The tiered process would use progressively more complex and accurate analyses to
determine whether the sediments have indeed been cleaned up similar to PSDDA and the
SMS itself. One possible approach would be as follows:
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Tier 1. Compare bulk sediment chemistry to SQS values. If sediment chemistry is below
SQS, then cleanup objective has been met. If sediment chemistry is above SQS, proceed to
Tier 2.
Tier 2. Conduct bioassays (suite to be determined) and compare results to reference
sediments (similar to SMS). If bioassays not significantly different (exact criteria to be
determined) from reference, then the cleanup objective has been met. If bioassays are
significantly different, then proceed to Tier 3.
Tier 3. Conduct benthic community analysis and analyze various measures (to be
determined but similar to Phase 1 Report) of abundance and diversity. (In this case the
simple SMS benthic measures might be used but some other more complex data analysis
must also be included).
Immediately after cap construction, only Tiers 1 and 2 could be used, because no benthic
community would be present. However, recourse to Tier 3 would be available several years
after construction.
In addition, the use of the word "prevent" in the cleanup objective definition appears to be
inappropriate. Asarco agrees that the exposure of receptors to contaminant effects can be
"limited" or "minimized." However, cleanup success should not be measured in terms of
absolute prevention of all exposure to contaminants to all potential receptors. It is possible
that minor exposures might take place, but in overall terms the remediation would still be
successful. The success of the remediation should be measure in terms of whether the entire
cleanup meets the overall goals of protection of human health and the environment.
Response: EPA agrees with the concept that a tiered approach is applicable to determining the
success of the remedy. The exact details of this approach will be determined as part of the Operation,
Maintenance, and Monitoring Plan (OMMP).
Asarco's concern regarding the use of the word "prevent" in the cleanup objective is noted by EPA,
however EPA believes that as a goal, the word "prevent" is still appropriate. EPA will keep the
wording of the cleanup objective as is.
Comment No. 34
Comment: Of greatest concern is that EPA defer to and enforce all Washington State
cleanup standards for groundwater and sediments. As was recently proved in the findings
for Asarco at the Asarco Everett facility, failure to enforce Washington State standards on
one site can have adverse impacts to another site cleanup. As Asarco is a PRP for another
Commencement Bay Superfund sediment cleanup action in the Hylebos Waterway, it is
imperative that uniform cleanup standards be employed throughout the entire
Commencement Bay cleanup area.
Response: Comment noted. The cleanup levels selected for this Site are consistent with ARARs
(including Washington State cleanup standards for groundwater and sediments) and have been
developed based on site-specific conditions and information. Further, the Washington Department of
Ecology concurs with the cleanup levels selected for the Site.
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Comment No. 35
Comment: 6.2 Sediment Cleanup Objectives
EPA's stated cleanup objective for sediments is to restore and preserve aquatic habitats by
limiting or preventing the exposure of environmental receptors to sediments with
contaminant above Washington State Sediment Management Standards.
Response: The comment has correctly restated EPA's cleanup objective. EPA assumes that CHB
concurs with EPA's objective.
Remedy Costs
Comment No. 36
Comment: (Table 7.2 and 7.3) Alternative S-1E: Dredge and Upland Disposal has a present
worth cost of $26.2 million for 88,000 cy. This is $298/cy. Alternative S-2D: Dredging and
Upland Disposal has a present worth cost of $3.6 million for 55,000 cy of Yacht Basin
sediment. This is $65/ cy. Why is one over 4.5 times more than the other?
Response: The difference in the costs for the Dredge and Upland Disposal alternatives for the Yacht
Basin versus the Nearshore area is due to the fact that the material from the Yacht Basin can be
accommodated under the onsite cap . If material was removed from the Nearshore area, it would need
to go offsite, because there is not sufficient capacity onsite to handle all of the nearshore sediment.
Offsite disposal is significantly more expensive than onsite disposal.
Comment No. 37
Comment: (Section 8.7) The sentence "For all sediment areas, upland disposal is less costly
than nearshore confinement" is not consistent with Table 7.2.
Response: DNR is correct - the statement is incorrect as written. Instead, it should read: "upland
disposal is less costly than nearshore confinement when the dredged material can be placed onsite."
Endangered Species Act and Biological Assessment Issues
Comment No. 38
Comment: We anticipated that the extension to the comment period would provide the
opportunity to review the Proposed Plan in the context of the Commencement Bay
Biological Assessment (BA). We view the BA as critical to decision-making at all scales in
the bay, including site-specific cleanup actions. Without consideration of the BA, we do not
believe that our common goal of achieving cleanup in a broader ecosystem management
context can be ensured. We also cannot evaluate the adequacy of the proposed site-specific
remedial action in achieving ESA compliance without review by and discussion with EPA
and National Marine Fisheries Service of the BA and the biological opinion. Until this
information and analysis is available, we remain concerned that the effects of the proposed
remedial action on critical habitats for chinook salmon are not resolved at either a site or
baywide scale.
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For example, we are concerned with the lack of information and guidance on the functional
linkages between deep water (>-10 MLLW) epibenthic habitats and the foodweb for young-
of-year and immature resident chinook salmon. Recent studies of the polychlorinated
biphenyls body burdens for Puget Sound chinook and herring stocks indicate an exposure
pathway link between the benthic community and the pelagic foodwebs of these species.
This information argues for a very conservative approach to remediating chemicals of
concern for bio accumulation, such as arsenic and mercury.
We are also concerned that the proposal does not restore the healthy nearshore habitats,
both as salmonid migration corridors and as intertidal feeding areas, that once existed at the
site. In addition, we believe that decisions regarding cleanup objectives are based on
incomplete information. We encourage incorporation of the latest information from the
federal services - particularly results of current NMFS efforts - on cleanup standards that
are protective of trust resources.
Available information suggests that numerous individuals from the White River chinook
stock are expected to rear nearshore at the Asarco site for extended periods. The proposed
plan does not provide sufficient information to determine the degree to which chinook
salmon will be restored and protected. We encourage EPA to more actively integrate the
numerous cleanup decisions necessary throughout Commencement Bay within the context
of the Commencement Bay BA and biological opinion. We are interested in working with
EPA on a management plan for the entire bay that defines both site-specific and baywide
implementation actions, with net gain in habitat area and function being one of the primary
plan objectives.
Response: The Biological Assessment (BA) being performed for Commencement Bay does not
address the Asarco sediment site (e.g., it covers the waterways within Commencement Bay only).
Instead, DNR is referred to the BA and Endangered Species Act (ESA) assessments being performed
specifically for the shoreline armoring being conducted under OU 02 and the sediment capping and
dredging proposed for the offshore areas of the Asarco Facility (two separate BAs and ESAs) .
As for concerns regarding bioaccumulation of chemicals at the Site, DNR is referred to the tissue
sampling (benthic and fish tissue samples) and the benthic community analyses completed by Asarco
as part of the Phase 1 sampling program. In addition, Asarco will analyze tissue samples after
cleanup to verify that bioaccumulation is not occurring at an unacceptable level.
Comment No. 39
Comment: (Section 5.2) It is unclear how healthy biological communities are being defined.
How was this determined? Diversity, abundance, both?
Response: Both.
Natural Resource Mitigation
Comment No. 40
Comment: Finally, we would like to discuss the potential reuse of the treated groundwater
as a resource for restoration of a stream delta estuary. Such a delta existed on-site prior to
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development. The value of these small estuaries as nodes of productivity is becoming more
widely recognized. Salmonid species such as chinook, chum, and cutthroat have been
documented to preferentially target these areas in their utilization of nearshore corridors.
The potential for creation of a stream delta estuary appears to exist on the southeast portion
of the site. Integration of planning for such a project with the remedial and damage
assessment actions may provide opportunities for an improved, less expensive, more
comprehensive project.
Response: EPA needs more information from DNR on the development of a stream delta estuary,
especially in light of EPA's 1995 ROD for the Asarco Smelter and current plans for shoreline
armoring and habitat restoration being conducted under this previous ROD. The shoreline armoring
and habitat restoration plans are available in EPA's Administrative Record for this site..
Comment No. 41
As we noted in our recent comments on the Nov. 1999 Explanation of Significant
Differences (ESD) for the Commencement Bay Nearshore/Tideflats Superfund Site (2 Feb.
2000), NOAA has consistently based our evaluation of the Commencement Bay
investigations and cleanup plans on five basic principles:
1. That cleanup(s) progress sooner rather than later to reduce continued exposure of trust
resources to contaminants;
2. A preference for complete removal of contaminants from the aquatic environment (most
contaminants originated from the uplands);
3. if the aquatic environment must continue to serve as the repository for the contaminated
sediments, we prefer that contamination not be transferred from impacted waterways to
otherwise clean areas for disposal;
4. Where remedial actions cause adverse impacts (during cleanup or disposal), mitigation
for lost natural resources or their services is required; and
5. Cleanup and disposal decisions must be made under a baywide planning and
evaluation effort, especially for threatened/endangered trust resources and their
habitats.
This Proposed Plan appears to satisfy our principles 1, 2, 3, and 5. Where mitigation is
required (principle 4) based on cleanup action details yet to be specified, we would strongly
recommend the enhancement of the nearshore/intertidal area immediately south of the slag
peninsula along Ruston Way. This could entail the removal of wood wastes from the bottom
and re-contouring to allow eelgrass propagation from the existing bed further south. We
look forward to reviewing a detailed Clean Water Act 404 analysis and/ or mitigation plan.
Response: Comment noted. Mitigation requirements associated with the remedy for OU 06 will be
addressed as part of the Clean Water Act 404 (b)(1) evaluation that is currently being conducted.
Comment No. 42
Comment: The facility's operations have filled and/or degraded a substantial acreage of
aquatic lands. The values of the public aquatic lands for a broad range of functions and
services are damaged. The proposed remedy does not restore those values, and Asarco has
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not proposed to compensate the State of Washington as a natural resource trustee for past
and on-going losses. We will seek natural resource damages for functions and services that
are not restored in order to compensate the citizens' natural resource trust values.
The extent of damages will be highly-dependent on the degree to which the functions of
aquatic lands have been and will continue to be injured by slag deposition/deposits,
groundwater, runoff, point discharges, and other releases of injurious contaminants. We
encourage the resolution of natural resource damages claims in conjunction with the
remedial action processes at the site.
Response: After EPA selects the remedy for the sediments, EPA will begin discussions with the
potentially responsible parties (PRPs) for cleanup of the Site. It is not clear how the federal and state
natural resource trustees intend to proceed with their potential claims against the PRPs. EPA will
cooperate with the trustees in the future to resolve natural resource damage claims.
Long-Term Monitoring
Comment No. 43
Comment: Asarco agrees that monitoring of remediated areas is needed to verify cleanup
success. However, Asarco does not believe that extensive long-term monitoring of other
areas is necessary and believes the cost of this monitoring is substantial given the limited
benefit of monitoring non-remediated areas. Asarco believes that EPA's proposed plan for
this sampling implies that the RI/FS process was somehow incomplete and that
contaminant effects area have not been adequately identified. This is not true. In fact, Asarco
and EPA have come to a consistent and scientifically supported decision on areas exhibiting
contaminant effects. Asarco also believes that monitoring constitutes a remedial action for
these areas and that EPA does not have authority under CERCLA to require actions for
these non-impacted areas.
The Proposed Plan indicates that monitoring of areas outside remediation units will be
conducted to "confirm the assumptions and conditions" used to make clean up decisions.
The Plan further indicates that based on this monitoring, some further action may be
needed. Sediment sampling to "confirm assumptions and conditions" regarding areas and
volumes of sediments that may exhibit contaminant effects was conducted during the RI
and FS studies consistent with Superfund Guidance. The primary purpose of the Expanded
RI/FS process was to determine those areas that exhibit contaminant effects, and therefore,
require remediation. Prior to conducting the Phase 1 sampling, an extensive monitoring
plan was developed with the full participation of EPA and its consultants including
methods for evaluating the results of that sampling. It was agreed at that time that a
"preponderance-of-evidence" approach would be used to evaluate the numerous types of
sampling and data analysis that were conducted. This original concept is entirely consistent
with the Superfund RI process, which should define the areas and volumes of contaminated
materials to be remediated. It has been Asarco's position since completion of the Phase 1
Report that the sampling and analysis effort provided more than sufficient information to
determine areas where action such as remediation is needed (with some exceptions in the
marina and north shore areas, which were addressed in subsequent sampling).
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Under CERCLA Section 104, EPA can take action when a hazardous substance is released
into the environment or threatened to be released. EPA can also take action if a there is a
release or threat of a release of a pollutant or contaminant which may present an imminent
and substantial danger to the public health or welfare. A "pollutant or contaminant" is
anything that, when released into the environment and "upon exposure, ingestion,
inhalation, or assimilation into any organism, either directly from the environment or
indirectly by ingestion through food chains will or may reasonably be anticipated to cause
death, disease " or problems with the organism or offspring. 42 USC § 9601(33).
The metals in the sediments outside the contaminant effects area have not been released
(they are in the slag matrix), nor are they likely to be released. Moreover, the metals in
sediments are not pollutants or contaminants because they are not causing effects. If there is
neither a release nor a threatened release of hazardous substances, contaminants or
pollutants, the agency cannot compel remedial or response action.
Response: Under Section 104 of CERCLA, EPA can take action when a hazardous substance has
been released into the environment or is threatened to be released. Arsenic, copper and other
hazardous substances were released into the waters and sediments of the Site as a result of smelter
activities beginning in the early 1900s. Hazardous substances continue to be released, or threatened
to be released, from the slag, groundwater, surface water, and sediments. Accordingly, EPA intends
to take action to protect human health and the environment from releases or threatened releases of
hazardous substances.
As discussed in the response to Comment No. 4, a "preponderance of evidence" approach was used to
evaluate the overall health of the sediment at the Site. This approach resulted in stations which
exhibited a wide range of effects. In other words, there were stations that showed no effects, stations
that showed some effects, and other stations that showed many effects. The latter stations (those
showing many effects) were selected as stations as requiring active remediation. That means, it was
determined that the effects were significant enough that dredging or capping was warranted (e.g.,
destroying the current habitat and allowing new habitat to recolonize was determined to be
appropriate). This area is called the "Contaminant Effects Area." As for those stations with minor
biological effects, this area was determined to require monitoring. It was determined that active
cleanup might result in greater net negative impacts through destruction of existing habitats than if
not remediated. This area is not "clean," as indicated by some biological effects, however, it was not
impacted enough to warrant destruction of the existing habitat. This "gray" area, therefore, is
determined to require some monitoring to ensure that RAOs are met. Those stations displaying no
effects are not proposed for active cleanup or monitoring.
Comment No. 44
Comment: Page 3, 5th bullet. This bullet states that Asarco will monitor the dredged area
"to ensure that it is not becoming recontaminated." Asarco is responsible for
recontamination, if any that originates from the Site, but cannot ensure that the Yacht Basin
will not become recontaminated from marina activities.
Response: Comment noted. The Operation, Maintenance, and Monitoring Plan (OMMP) will
address this issue. Monitoring strategies and procedures will be identified to produce data that will
distinguish between contamination sources to the extent possible.
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Comment No. 45
Comment: 9.2.4 Long-Term Monitoring
Components of the long-term remedial monitoring plan must include action plans for
earthquakes, high-intensity storm events, severe tide/wind storms, etc.
Response: An Operation, Maintenance, and Monitoring Plan (OMMP) will be prepared as part of
the remedial design. The OMPP will identify inspection and monitoring procedures to verify that the
elements of the remedy are performing as intended or, if they are not, to identify needed repairs on a
timely basis. The OMMP will call for special inspections following major storms or earthquake
events.
Comment No. 46
Comment: (Section 7) What is the term of the OMMP?
Response: The Operations, Maintenance, and Monitoring Plan (OMLMP) will have a duration of
decades. The minimum duration of the monitoring period will be determined during development of
the OMIMP. Extension of the monitoring beyond the minimum period will be dependent on the
monitoring results and associated decision rules will be determined by EPA.
Comment No. 47
Comment: (Section 8.2) The plan should require that institutional controls, maintenance and
monitoring results be shared and coordinated with DNR.
Response: Discussions between EPA, DNR, and Asarco will address these concerns as the RD/RA
process proceeds. All documents associated with institutional controls, maintenance, and monitoring
will be available for public review. Therefore, these documents will be available to DNR.
Comment No. 48
Comment: NOAA appreciates the efforts the two remedial project managers and ASARCO
have made to incorporate previous NOAA technical comments and suggestions into the
overall cleanup of the former ASARCO Smelter Facility. By combining parts of both
operable units, it appears that the sediment remediation will be accomplished sooner than
originally scheduled and the use of the upland disposal site for the Yacht Club sediments
further streamlines the cleanup.
The natural resource agencies have expended considerable time and effort providing
technical advice to EPA, Ecology, ASARCO, and their consultants - this Proposed Plan
suggests that it was worth the effort since most of NOAA's previous concerns about the
sediments have been addressed. We want to encourage EPA, Ecology, and ASARCO to
continue to seamlessly integrate the sediment remediation with the shoreline stabilization.
In this way, there should be no wasted efforts between the two operable units cleanups and
the impacts to the natural resources will be minimized while the on-going exposures to
contaminants will be curtailed sooner rather than later.
NOAA strongly supports EPA's requirement for long-term monitoring of the remedy. Our
only concern with the proposed monitoring is that it does not include measuring
contaminant concentrations in the waters of Commencement Bay adjacent to the facility
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shoreline. As explained in our section-specific comments below, we think that monitoring
water quality in Commencement Bay is critical and we recommend that EPA include
offshore monitoring in the final plan.
Response: The Operation, Maintenance, and Monitoring Plan (OMMP) will include provisions for
sampling Commencement Bay waters at the shoreline.
Comment No. 49
Comment: Pg 2: Elements of the Preferred Alternative, Groundwater: The first item
identifies limiting groundwater "loading" to Commencement Bay as a remedial objective.
The second item identifies monitoring of groundwater as the method to document success
or failure of the remedy. However, the Ground water-Sediments Task Force determined that
two processes at the site complicate calculations of contaminant loading to Commencement
Bay from discharging groundwater:
(1) Tidal cycles in Commencement Bay cause significant fluctuations in the hydraulic
gradient at the CB shoreline; these tidal waters intermittently enter the fractures
in the slag along the shoreline and mix with discharging groundwater, altering
the groundwater gradient, discharging water volumes and the concentration of
conservative constituents, such as chloride (CI); and
(2) The solubility of the metal and metalloid (e.g., arsenic) ions that are contaminants
of concern at the site varies with changes in pH and/or redox conditions, both of
which are altered as the groundwater mixes with saline, oxygenated seawater
within the fractured slag before discharging into Commencement Bay. These
processes are also described at the bottom of page 7 in the Proposed Plan.
Because measurements of groundwater gradients and contaminant concentrations in upland
wells are an incomplete predictor of the contaminant loading to Commencement Bay (as
explained above), and the dilution from tidal mixing at the shoreline is significant but not
precisely quantified; the only way to determine if the shoreline water of Commencement
Bay is not contaminated by the metal and metalloid contaminants from the site is to sample
the shoreline waters of Commencement Bay and analyze for these constituents.
Response: The Operation, Maintenance, and Monitoring Plan (OMMP) will include provisions for
sampling Commencement Bay waters at the shoreline.
Comment No. 50
Comment: Pg 5: State Sediment Management Standards - Sediment Cleanup Criteria:
BASIS: Numerous sediment samples at the site had extremely high concentrations of metals
and metalloids, variable laboratory bioassay results, and benthic community analyses that
did not show any statistically significant differences from reference. The apparent absence
of the expected response (mortality leading to benthic community alterations) at these
stations may result from the physical structure of the slag that contains most of the
contamination. However, very high concentrations of contaminants remain at the site, and
ecological indicators of an adverse response to these contaminants were varied. The toxicity
of some of these contaminants can change with changing environmental conditions, e.g.
temperature or oxygen availability, and toxicity can vary by organism lifestage. Therefore, it
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is important that areas where high concentrations of contaminants remain in contact with
ecological receptors are monitored over the long-term to demonstrate continued ecological
protectiveness.
NOAA supports the proposal not to require active remediation of these areas on the
condition that EPA require long-term monitoring to demonstrate whether this decision
continues to be protective. It is recommended that this monitoring be coordinated with the
long-term monitoring of benthic communities in remediation areas that are dredged and/ or
capped to make efficient use of equipment and labor.
Response: EPA concurs. Long-term monitoring will be performed in the "gray" areas that indicated
some biological impacts (but not enough impacts to warrant active remediation). The timing of this
monitoring will be addressed in the Operations, Maintenance, and Monitoring Plan (OMMP).
Comment No. 51
Comment: Pg. 7, Sec. 3.1 Groundwater: [As stated in the Proposed Plan] "Groundwater at the
Facility flows from the southwest to northeast and ultimately discharges to Commencement
Bay."
Because Commencement Bay is the ultimate recipient of the contaminated groundwater,
and because ecologic receptors along the Commencement Bay shoreline can be adversely
affected by these contaminants, NOAA supports the preferred remedy on the condition that
long-term monitoring of the site include collection of shoreline water samples for
contaminant quantification.
Response: Comment noted. The Operation, Maintenance, and Monitoring Plan (OMMP) will
include provisions for sampling Commencement Bay waters at the shoreline.
Comment No. 52
Comment: Pg. 8, Sec. 3.1 Groundwater: [As stated in the Proposed Plan] "DMA-related organic
compounds are also present in the shallow groundwater system. However, the DMA,
arsenic, and copper in the DMA area do not appear to result in any greater exceedances of
surface water criteria in the adjacent Commencement Bay than observed elsewhere at the
Facility. For this reason, no special groundwater remedial action is planned for the DMA
area. However, groundwater monitoring in the DMA area will be part of the post-remedial
action monitoring program."
NOAA can support a decision not to take action to reduce contaminants in groundwater at
the DMA area, only if there will be long-term monitoring of the receiving water along the
shoreline of Commencement Bay where NOAA trust resources are potentially affected by
these contaminants, and with a commitment that if the monitoring data indicate this
decision is not protective of the environment, other remedies will be evaluated for the DMA
area.
Response: Comment noted. The Operation, Maintenance, and Monitoring Plan (OMMP) will
include provisions for sampling Commencement Bay waters downgradient of the DMA area.
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Comment No. 53
Comment: Pg. 10, Sec. 3.2, Sediment: [As stated in the Proposed Plan] "Some concentrations of
metals and/ or biological impacts (as measured with bioassays) exceeded the CSL outside of
the Contaminant Effects Area in what is depicted as the "Moderate Impact Area" (Figure 5).
The benthic communities in the Moderate Impact Area appear healthy. Because active
cleanup might result in greater net negative impacts through destruction of existing habitats
than if not remediated, long-term monitoring is proposed in these areas to verify that the
overall health of the ecosystem (after the upland and offshore cleanup activities are
completed) is remaining the same or improving."
NOAA supports the proposal not to require active remediation of these areas on the basis
that EPA will require long-term monitoring to demonstrate whether this decision continues
to be protective. It is recommended that this monitoring be coordinated with the long-term
monitoring of benthic communities in remediation areas that are dredged and/ or capped to
make efficient use of equipment and labor.
Response: EPA concurs. Long-term monitoring will be performed in the "gray" areas that indicated
some biological impacts (but not enough impacts to warrant active remediation). The timing of this
monitoring will be addressed in the Operations, Maintenance, and Monitoring Plan (OMMP).
Comment No. 54
Comment: Pg. 13, Sec. 5.2, Ecological Risk Assessment, Groundwater: [As stated in the
Proposed Plan] "The findings of the Task Force regarding the impact of groundwater on the
sediments and waters of Commencement Bay indicate the following:
• The amount of metals currently being discharged (pre-remediation conditions) by
ground-water and surface water discharges to Commencement Bay results in the
exceedance of applicable water standards for certain metals (e.g., arsenic and copper)
within a few feet of the shoreline. The metals load discharged to Commencement Bay by
groundwater is expected to decrease after remediation because the most highly
contaminated source materials will have been removed and groundwater flow to
Commencement Bay will be reduced."
NOAA agrees with EPA's assessment and strongly supports all efforts to reduce
groundwater flows through the site which would continue to transport metals into the
marine environment. Early interception of the groundwater upstream of the site should be
maximized, the placement of an impervious cap over the site to eliminate surface water
percolation downward then seaward is imperative, and co-precipitation treatment of
collected runoff waters on site should be emphasized, if this technique removes significant
levels of metals. However, we want to emphasize that the only means to ascertain whether
the remedial actions have reduced the discharge of metals (and metalloids such as arsenic)
along the shoreline of Commencement Bay to bring them into compliance with applicable
water standards is to include sampling of the shoreline water of Commencement Bay in the
post-remediation monitoring. Only a well-designed sampling plan can demonstrate to all
parties that the selected remedy has caused shoreline areas to achieve the applicable water
quality criteria.
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Response: Comment noted. The Operation, Maintenance, and Monitoring Plan (OMMP) will
include provisions for sampling Commencement Bay waters at the shoreline.
Comment No. 55
Comment: Pg. 16, Sec 6.1, Groundwater Cleanup Objectives: [As stated in the Proposed Plan]
• "Long-term monitoring"
NOAA recommends that this be amended to read; "Long-term monitoring of groundwater
and (Commencement Bay) receiving water" in order to demonstrate that the water column
used by marine organisms along the shoreline of Commencement Bay is protected by the
remedy.
Response: Comment noted. The ROD indicates that long-term post-remedial action monitoring will
include provisions for sampling Commencement Bay waters at the shoreline.
Comment No. 56
Comment: Pg. 23-24, Sec. 8.2 Compliance with Federal and State Environmental Standards,
Groundwater: [As stated in the Proposed Plan] "Samples of Commencement Bay water
collected at the shoreline confirm that current laws for marine water quality are not
currently met at all locations and at all times. However, metals concentrations in
groundwater flowing toward the shoreline are expected to decrease in future years in
response to the site-wide changes (i.e., reduced groundwater discharge) affected by the
cleanup. These changes are expected to allow state and federal laws to be met at the end of
the remedy."
NOAA agrees with the preceding analysis and believes that monitoring of water quality
along the shoreline, where contaminated slag will remain in place, is necessary to
demonstrate that the remedy has resulted in compliance with Federal and State
Environmental Standards for the waters (and habitats) of Commencement Bay. NOAA
recommends that the Washington State Water Quality Criteria for protection of marine life
be utilized as benchmarks for protection of the water column component of marine habitat.
Response: EPA concurs. Arsenic and copper have been identified as the two constituents of concern
for groundwater. The cleanup levels for these two metals are 6 ng/L and 3.1 ng/L, respectively. These
levels meet or exceed the Washington State Water Quality Criteria for protection of marine life.
Other metals data that may be collected during the long-term monitoring program will also be
benchmarked against their respective Washington State Water Quality Criteria in accordance with
procedures outlined in the final Operation, Maintenance, and Monitoring Plan (OMMP).
Other Comments
Comment No. 57
Comment: (Section 9.1.1) What will be the final quality of treated groundwater?
Response: At this time, it is expected that groundwater requiring treatment will be accommodated in
the onsite stormwater treatment system to be constructed under the upland remedial action (governed
by the 1995 ROD for OU 02). At this writing, the design of this system is in progress. Both polymer-
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and filtration-based systems designed to remove suspended metals from stormwater are being
evaluated by Asarco. The post-treatment quality of the stormwater will not be determined until
ongoing engineering studies are complete. However, design criteria call for the stormwater to meet
design criteria applicable to OU 02.
Comment No. 58
Comment: As a long-time resident of North Tacoma, I would like to take this opportunity to
comment on the EPA cleanup of the Asarco smelter. I would like to voice my concerns
about the long-term effectiveness of the proposed disposal alternatives. I can not see how
capping contaminated sediments on-site with 1 meter of clean material represents a safe and
reliable solution. Humans have been burying garbage for thousands of years, surely we can
do better than this by now? I would like to encourage the EPA to support the development
and use of improved treatment methods. I believe the government has an obligation to the
future health and well being of humans and the environment to forward progressive
solutions. In addition, I am concerned about the storage of contaminated sediments so near
the water. Earthquakes and slides could yield potentially disastrous results. Furthermore,
there is the corrosive, erosive capacity of the salt air and water to consider. Hopefully, the
EPA will continue to re-evaluate conditions at the Site and apply improved treatment
measures as they become available.
Response: The comment advocates removal (dredging) and treatment of contaminated sediments. Of
the total area subject to sediment remediation, approximately 55 percent (Nearshore/Offshore and
Northshore areas; 19.5 acres) will be capped and 45 percent (Yacht Basin; 15.5 acres) will be dredged.
Capping of the Nearshore/Offshore and Northshore areas was selected as the preferred remedy based
on application of the five balancing criteria required by the National Contingency Plan (see page 22 of
the Proposed Plan). EPA agrees that treatment of the sediments, preferably in-place, to destroy
contaminants of concern is the most desirable end point. Potential treatment of marine sediments was
evaluated by EPA as part of the Feasibility Study process. Several technologies groups were evaluated
including thermal destruction, thermal desorption, chemical separation, sediment washing, and in-
place solidification/stabilization. As part of this evaluation, EPA did not identify any established
sediment treatment options that are reliable and cost-effective. This decision was mostly due to the
difficulty in removing these sediments, based on the nature of the sediments (some have large chunks
of slag), the extensive depth of contamination, and the steep slopes off the Site. Further, the net benefit
of treatment for some of the treatment technologies was limited (e.g., the end result after treatment
was not much different than the slag presently on the Site).
Comment No. 59
Comment: The Proposed Plan specifies an upland source of capping material. There is no
justification for specifying that the cap material be derived "from an upland source" and
nothing that should preclude an aquatic source of material. Cap material from an aquatic
source would be as suitable or more suitable than material from an upland source for
biological colonization. There should be no difference in the effectiveness of contaminant
isolation with either an upland or an aquatic source. Appropriate material may be available
at a lower cost from a marine source. Asarco believes the location and selection of capping
material is a Remedial Design task and that the Proposed Plan should not preclude aquatic
sources of capping material.
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Response: Comment noted. EPA agrees that the cap material could originate from either an upland
or aquatic source as long as it meets the minimum specifications to be established during remedial
design.
Comment No. 60
Comment: The Proposed Plan delays a final decision on the need for additional
groundwater controls pending additional remedial design analysis. Asarco believes that the
existing information demonstrates that additional groundwater controls are not appropriate
and that ongoing evaluations during Remedial Design are unnecessary.
The hydrologic analyses of the feasibility of additional upgradient groundwater controls
have been completed and draft reports have been submitted to EPA. These analyses
demonstrate that additional groundwater controls would capture negligible amounts of
additional groundwater and contaminants. Capture and treatment would reduce some, but
not all metal concentrations in the captured groundwater and would eliminate the current
reduction in arsenic concentrations provided by natural attenuation on the Site. Therefore,
little or no environmental benefits would be realized by the additional groundwater
capture. Costs associated with constructing an interception system and the additional
treatment costs would be substantially and disproportionately expensive relative to the
environmental benefit received.
Response: The Proposed Plan was written before the groundwater diversion issue had been fully
explored by EPA and Asarco and prior to Asarco's submission of final reports addressing this issue.
Since publication of the Proposed Plan, Asarco has demonstrated that inclusion of additional
groundwater diversions at this time (specifically in the vicinity of the Cooling Pond, East Stack Hill
drainages, and along Ruston Way) would be impracticable from a cost/benefit standpoint (see
Appendix A of the report titled "Historical Summary of the Evaluation of Groundwater Remedial
Alternatives, Asarco Tacoma Smelter Site," Hydrometrics, June 2000; this document is part of the
Administrative Record).This impracticability demonstration was required to satisfy MTCA remedy
selection requirements.
Comment No. 61
Comment: The Proposed Plan presumes that treatment of groundwater will be necessary.
The Proposed Plan should clearly state that treatment is not required unless treatment is
necessary to meet Remediation Goals. Moreover, it is important to note that:
Design of the stormwater treatment system is an Upland Remedial Design task.
Design of the stormwater treatment system is based on treating stormwater, not
groundwater.
Design of the stormwater treatment system is ongoing.
Therefore, the Proposed Plan needs to be flexible regarding treatment of groundwater by
the yet to be designed stormwater treatment system. One area in which the Proposed Plan
may unduly constrain design of the surface water treatment system regards the treatment of
groundwater during baseflow (i.e. non-stormwater flow) periods. The Proposed Plan needs
to allow the potential for bypass of captured groundwater from treatment during baseflow
periods if such bypass is consistent with stormwater treatment.
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Response: EPA agrees that captured groundwater may need to be treated. The quality of
groundwater captured in each of the primary diversion systems has not yet been estimated or
otherwise measured. Once the quality of this groundwater is known with reasonable certainty, a
decision can be made regarding the need for treatment. The Proposed Plan text concerning this issue
was intended to mean that groundwater requiring treatment would be treated in the stormwater
treatment system to be constructed as part of the remedy for Operable Unit 02. Based on
commitments made by Asarco, this is the current approach for providing any required treatment of
captured groundwater. Asarco also has the flexibility to process and treat groundwater separately
from stormwater. The language previously included in the Proposed Plan has been modified in the
ROD to clarify this issue.
Comment No. 62
Comment: Page 4, 3rd bullet. The Refinement of the Proposed Remedy Report was revised
and submitted to EPA on January 5,1999. This document should be referenced instead of
the August 1999 draft.
Response: Comment noted. The correct citation has been provided in the ROD.
Comment No. 63
Comment: Page 4, document list. The Copper in Nearshore Marine Water Technical
Memorandum submitted to EPA on June 23,1999 should be included in the list of
documents providing additional detailed information.
Response: Comment noted. This document has been included in a list of "key documents" presented
in the ROD.
Comment No. 64
Comment: Page 6, first para. Sentence states "The shallow aquifer system beneath the
Facility is largely recharged by lateral flow of groundwater from the southwest (Ruston
area) and infiltration of precipitation and surface water run-on."
It would be more accurate to say "The shallow aquifer system beneath the Facility is largely
recharged by infiltration of precipitation and surface water run-on and to a minor extent by
lateral flow of groundwater from the southwest (Ruston area)."
Response: Comment noted. The language previously included in the Proposed Plan has been
modified in the ROD to clarify this issue.
Comment No. 65
Comment: Page 9, last full para. This paragraph seems to state that copper exceeds the
marine chronic criteria (MCC) at all locations in Commencement Bay near the Site. This is
not true. The best data available to Asarco and EPA indicates that copper concentrations
currently exceed the MCC at about half of the sampling locations along the shoreline and
only in very close proximity to the slag shoreline. At most locations, seawater a few feet
away from the slag meets all aquatic life criteria for copper and all other metals.
In conjunction with the Asarco Sediment/Groundwater Task Force (ASGTF) Asarco
conducted two rounds of special seawater monitoring in 1999 to determine copper
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concentrations in seawater near the Site. This seawater monitoring employed ultraclean
sampling and analytical techniques and yielded analytical sensitivities and accuracies
several orders of magnitude better than techniques previously available. Results of this
monitoring were submitted to EPA in a June 1999 Draft Technical Memorandum and in a
November 16,1999 data transmittal. The ultraclean monitoring data demonstrates that
copper concentrations do not exceed criteria in all samples; only samples collected near the
shoreline in some areas.
Response: Comment noted. The language previously included in the Proposed Plan has been
modified in the ROD to clarify this issue.
Comment No. 66
Comment: Page 13, The First Bullet is incorrect regarding Task Force findings related to
arsenic. The Task Force found (see page 6-5 of the March 1999 ASGTF Group 5 Technical
Memorandum) that groundwater discharges currently cause water column concentrations
to exceed only the copper chronic aquatic life criterion. Current water column
concentrations of arsenic and other metals are better than the chronic aquatic life criterion.
Response: Comment noted. The language previously included in the Proposed Plan has been
modified in the ROD to clarify this issue.
Comment No. 67
Comment: Page 14,1st para. What does "nonminimally impacted" mean?
Response: The word "nonminimally" is a typographical error. It should read "non-
impacted/minimally impacted station..
Comment No. 68
Comment: Page 16, 2nd para. Deep groundwater does not presently exceed MCLs or MTCA
standards for any parameters except possibly arsenic (see Summary and Interpretation of
1994,1995,1996,1997 and 1998 Post-RI Long-Term Monitoring Results (Hydrometrics, 1999)
and Table 4-3 in Summary and Interpretation of Production Well Abandonment Action-
Specific Monitoring Results (Hydrometrics, June 1997).
Response: Comment noted. This language previously included in the Proposed Plan does not appear
in the ROD.
Comment No. 69
Comment: Page 23, last para. The Plan states "Modeling performed by the Task Force
indicates that state and federal laws applicable to protection of marine water quality may
not be currently achieved within a few feet of the shoreline for all metals." Although model
results did indicate some metal concentrations above marine chronic criteria, the Task Force
placed more emphasis on empirical data rather than model predictions in concluding
impacts from groundwater. The Task Force concluded that with the sole exception of
copper, groundwater discharge currently does not cause metal concentrations to be higher
than marine chronic criteria (see page 6-5 of the March 1999 ASGTF Group 5 Technical
Memorandum).
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PART III
Response: Comment noted. The language previously included in the Proposed Plan has been
modified in the ROD to clarify this issue.
Comment No. 70
Comment: Page 25, 2nd para. States "The in situ treatment and seawater injection treatment
alternatives would promote chemical precipitation (i.e., "settling out") of arsenic from
groundwater, thereby reducing the arsenic load reaching Commencement Bay." Based on
the Asarco Sediment/Groundwater Task Force evaluations, the effectiveness of in situ
treatment is uncertain given that seawater already oxidizes and removes arsenic to the
extent practical, with the exception of the Southeast Plant area.
Response: Comment noted.
Comment No. 71
Comment: Page 28, bottom of page. It states "Additional groundwater interception is being
considered at the Facility, and may also be considered by EPA at a later date. The need for
additional groundwater interception would be based on the results of ongoing groundwater
sampling." Earlier in the Proposed Plan (3rd paragraph, pg. 27) it is stated that additional
diversions are disproportionately expensive and would only be considered if cleanup goals
could not be met. Asarco agrees that additional interception is disproportionately expensive
and believes that additional interception should only be considered if cleanup goals are not
met.
Response: EPA acknowledges the inconsistency on this issue as presented in the Proposed Plan.
Since publication of the Proposed Plan, Asarco has demonstrated that inclusion of additional
groundwater diversions at this time (specifically in the vicinity of the Cooling Pond, East Stack Hill
drainages, and along Ruston Way) would be impracticable from a cost/benefit standpoint. Additional
groundwater interception in the future is possible if it is determined that groundwater cleanup levels
are not being met and additional groundwater capture is practicable considering the expected
reduction in risk to human health and the environment. EPA expects that this issue would be
assessed as part of the Five-Year Review process.
Comment No. 72
Comment: Page 29, 3rd para. It [the proposed plan] states "At a minimum, monitoring wells
at the downgradient perimeter of the Facility (along the shoreline) will be monitored,
including wells near source areas." Rather than "wells near source areas", it would be better
to say, "wells near source areas if, and to the extent compatible with, protection and
maintenance of the cap."
It further states "In addition, should the groundwater indicate high concentrations of
metals, contingency actions, such as additional groundwater diversions, may be
considered." What is meant by high metal concentrations? Above cleanup goals? Where? It
is expected that concentrations will remain above cleanup goals in and near source areas but
this occurrence alone should not trigger additional diversions. Given EPA's broad authority
under the five year review provisions of the Upland ROD, this last sentence is unnecessary
and should be deleted. If the sentence is retained, then EPA should specify the trigger
criteria of "high concentrations of metals." Asarco believes appropriate trigger criteria
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PART III
would be remedial action objectives and remediation goals (including Asarco's proposed
changes) at a compliance point located in surface water along the armored slag shoreline.
Response: Monitoring wells will likely be required near primary source areas (or former source
areas). Some of the existing wells may meet these monitoring needs but it is likely that new wells will
also be needed in locations not previously monitored or to replace old monitor wells removed to
accommodate remedial action construction activities. The technical objectives of the monitoring
program will dictate the actual well locations. If installation of a new well (or maintenance of an
existing well) is in conflict with protection and maintenance of the cap, the competing needs will be
assessed to determine the most appropriate solution.
The text addressing "high concentrations of metals" in groundwater and the possibility of "additional
groundwater diversions" was intended to communicate that further groundwater capture may be
necessary in the future if groundwater quality goals are not being met. The details of the thresholds
and conditions that would trigger such an action (or an evaluation to determine if action is required)
need to be determined during development of the Operation, Maintenance, and Monitoring Plan
(OMMP). In general, EPA recognizes that groundwater cleanup levels may not be achieved in the
slag matrix or immediately downgradient of other areas where source materials are present. The goal,
however, is to manage the contaminant concentrations in groundwater such that applicable marine
surface water quality standards and risk-based levels protective of human health are not exceeded in
Commencement Bay waters at the shoreline.
Comment No. 73
Comment: On behalf of Citizens for a Healthy Bay (CH B), an organization representing 850
members of the Tacoma and Greater Commencement Bay community, thank you for the
opportunity to comment on the proposed remedial plan for Asarco Smelter site
groundwater and sediments. Except as discussed below, CHB generally agrees with the
remedial actions proposed for site sediments and groundwater.
Response: CHB's general and conditional agreement is noted.
Comment No. 74
Comment: 7.1 Groundwater
We agree with the stated preferred alternative GW-B involving intercepting and treating site
groundwater prior to discharging into Commencement Bay. We are concerned that the
remedy be scaled to handle large magnitude storm events and associated increases to
groundwater.
Also, use of an on-site cap to limit infiltration of precipitation into the soil will increase the
amount of stormwater runoff and contaminants commonly associated with stormwater
runoff. How will recontamination of the sediments by toxins such as PAHs, BEPs, fertilizers,
herbicides, insecticides, etc. be avoided? We do not wish to see one set of problems
exchanged for another.
Response: The capacity of the groundwater diversion system will be engineered to accommodate a
range of possible flows based on the expected fluctuations in seasonal groundwater conditions. The
possible short-term impacts from large storm events will be considered in the engineering assessment.
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PART III
Stormwater conveyance and treatment systems are being designed under the 1995 ROD for Operable
Unit 02. Future stormwater runoff from the Site will be subject to applicable laws and regulations. In
addition, the long-term monitoring program will be designed to identify increases in contaminant
loading to the sediments or waters of Commencement Bay such that preventive action can be taken if
warranted. Further, the stormwater discharged to Commencement Bay is expected to meet marine
chronic criteria with treatment and use of a mixing zone.
Comment No. 75
Comment: Citizens for a Healthy Bay urges you to consider that private citizens, aquatic
communities and the improved health of Commencement Bay are the largest stakeholders
in the cleanup and disposal of contaminated sediments and groundwater at the former
Asarco Smelter site. As a citizen-based representative of that community, Citizens for a
Healthy Bay is concerned about the decisions EPA will make regarding remediation at the
Asarco site. We urge the Environmental Protection Agency to make decisions that will
positively affect the primary stakeholders in the cleanup of Asarco sediments and
groundwater.
Response: EPA concurs.
Comment No. 76
Comment: We also encourage removal of any leaking, unused and/ or abandoned pipes and
any other debris or unnecessary structures along the shoreline.
Response: EPA concurs. The disposition of leaking, unused and/or abandoned pipes and other debris
structures along the shoreline is being addressed as part of the ongoing remedial design for Operable
Unit 02 (i.e., the Upland ROD).
Comment No. 77
Comment: Going through the Fact Sheet on the Former Asarco Smelter cleanup from Jan.
2000,1 wish to enter the following written comments on the clean up.
I am a boater and live and have lived in the Yacht Basin for the last 15 yrs. from just before
the Smelter shut down. I have seen the Basin so dead and hot you could almost power a
light bulb, to today, where electroylsis is almost gone and sea life has come back. Years back
we never had much growth on boat bottoms, now we have barnacles and mussels and
growth of seaweed. What are you doing, I have faith it is a good job and see nothing to
change. I only want to push 2 points that relate to me.
Re: Yacht Basin Area. The bottom is deep mud gunk. In spite of the returned sea life, this
life cannot be safe do [sic] to the bottom it lives over. And in some cases on and in.
I wish to strongly push for the dredging of the Basin to at least 2 ft. Absolutely no less and
possibly more. I know what this stuff looks like and is.
My only other concern is the slow speed that all of the cleanup is going at. Please no more
extensions. Lets just get it done!
Response: Comment noted. Regarding the depth of dredging in the Yacht Basin: Asarco will collect
additional sediment samples from the Yacht Basin this year. The data will be used to plan dredging
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PART III
depths. For the purpose of site cleanup, dredging will occur to the depth required to meet the cleanup
criteria. As such, the final dredging depth is expected to vary by location.
Comment No. 78
Comment: Tacoma Yacht Club should be formally designated as a stake holder in the
design and implementation of the Remediation Plan for the Yacht Basin. The club will
formally designate a committee to laison [sic] with E.P. A., Asarco and other active parties.
Response: A project of this size and complexity requires coordination between all affected parties. To
that end, Asarco has made a commitment to work directly with the Tacoma Yacht Club on Yacht
Basin dredging issues. EPA will take steps to see that Asarco coordinates with the Yacht Club to the
extent necessary.
Comment No. 79
Comment: Pg. 21, Sec 7.1 Groundwater: [As stated in the Proposed Plan] "No remedial action
is planned for the Slag Peninsula area (approximately 85,000 yd2 or 17.5 acres) because the
water depths and steep slopes make capping or dredging technically impracticable."
NOAA supports EPA's position of not trying to actively remediate the steep portions of the
Slag Peninsula Unit located in deep water. Conventional capping techniques do not appear
to be productive because of the steep slopes and water depths. NOAA prefers intertidal and
shallow subtidal capping to be placed only when equivalent (or more) fill is removed so that
there is no net loss of aquatic habitat; for that approach to be used on the slag peninsula it
would require the removal of too much of the peninsula before reaching gentle enough
slopes for the capping material to repose in perpetuity. We are unaware of any other cost-
effective and environmentally-sensitive remediation technology to solve these problems.
Response: Comment noted.
Comment No. 80
Comment: My standpoint, you must understand, comes from a metallurgical engineer who
had an opportunity to tour the ASARCO smelter while a young college student. It is
unfortunate to the community and the area as a whole that so much toxic substances were
released into the environment in the name of progress and the almighty dollar. It should
also be remembered that the plant offered employment to numerous workers during its
lifetime. It was a monument to the ingenuity of metallurgists while now becoming a bane to
those of us in the profession. It is demoralizing to think that the metals industry has had to
cope with changes that sometimes make my training obsolete.
Just as a passing thought; there are plans to remove and store in a landfill, the contaminated
soils around the Ruston plant. And the Seattle-Taocma [sic] airport is looking for fill for
their third proposed runway. Abra-cadabra! Why not use this soil for their fill and kill two
birds with one stone? I had heard some statistics about the amount of fill needed for the
SEA-TAC airport and the time needed to complete their plans, much to the consternation of
the local residents.
Another thought; why not sell, for refining, the waste products from the ASARCO plant? It
used to be that tailings piles from older mines would be reprocessed again and again to
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PART III
remove the smallest traces of valuable metals. Arsenic still has used in rodenticides. Lead is
used in storage batteries. Cadmium is used in low-melting point alloys. What other
treasures could be gleaned from all the waste?
The EPA plan to cover the site with non-permeable material does not take into account one
thing; water seeping UP through the covering layer. This is something that must be
considered in our wet Washington weather.
Men have torn down mountains to get to precious metals for a long time. If the material at
Ruston is offending, why not dig out a big hole and put it back into those torn-down
mountains?
These are my thoughts and suggestions concerning the treatment of the wastesite at
ASARCO's Ruston plant. I hope they are doing a better job of not polluting in their new
location in the southwestern USA. It was a kick in the butt to see them leave town. That was
one less place I could have sought gainful employment from.
Response: EPA offers a four part response:
1. Disposal of contaminated soils and sediments at Seattle-Tacoma Airport - We assume that the
phrase "contaminated soils around the Ruston plant" refers to both the contaminated terrestrial
soils and marine sediments that are scheduled for onsite contaminant at the Site. Plans call for
these materials to be disposed of in either the engineered On-Site Containment Facility (OCF) or
under the proposed low permeability cap. Soils and waste materials from the upland portion of the
Site and soils from the Ruston area were specifically addressed in the 1995 ROD addressing
Operable Units 02 and 07 and in the 1993 ROD addressing Operable Unit 04 (OUs 02, 07, and
04 include cleanup of upland portion of the Site, demolition of Asarco facilities, Asarco Off-
property soils, respectively). Per the 1995 ROD, EPA has determined that the soils and wastes
from OUs 02, 04, and 07 are to be disposed of at the former Asarco facility. EPA did not evaluate
the possibility of exporting dredged sediments to Seattle-Tacoma Airport as part of the RJ/FS for
OU 06 (Sediments/Groundwater). We believe that there are a number of significant difficulties
with this approach that make it infeasible. These include the cost of transporting the material
from Tacoma to the airport, environmental regulations that preclude disposal of contaminated
material at facilities that are not designed for such purposes, and the cost and time associated
with negotiating such a proposal with the Port of Seattle and nearby members of the community
who may be affected, among others.
2. Recycling waste material - As discussed above, the 1993 and 1995 RODs address all of the
terrestrial soils and waste materials associated with the Asarco facility. Remediation is either
underway (OUs 04 and 07) or nearly underway (OU 02). A number of physical and chemical
treatment processes, some of which included metals reclamation, were evaluated as part of the
Feasibility Study for OU 02. It was determined that reliable cost-effective alternatives were not
feasible or practicable due to the nature and volume of the waste materials.
3. Seepage through the site cap - The low permeability cap will be placed above the seasonal high
groundwater table. In addition, the cap system will include a drainage layer to direct subsurface
water to the surface water diversion system.
4. Disposal of contaminated material at former open pit mines - The comment suggests that
contaminated soils, wastes, and sediments could be returned to former mine sites for final
disposal. As discussed above, the 1993 and 1995 RODs address all of the terrestrial soils and
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PART III
waste materials associated with the Asarco facility. EPA did not evaluate the possibility of
exporting dredged sediments to mine sites. Many of the same difficulties and costs addressed in
the response to the Seattle-Tacoma Airport comment (above) apply to this alternative.
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References
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References
District Court of Washington, June 2000. United States vs. Asarco, Inc. Commencement Bay
Nearshore/Tideflats Superfund Site, Asarco Smelter Consent Decree, Amendment
Number One.
Hydrometrics, Inc. January 1993. Asarco Tacoma Plant Yacht Club Breakwater Remedial
Investigation, Tacoma, Washington.
Hydrometrics, Inc. August 1993. Asarco Tacoma Plant Feasibility Study, Tacoma, Washington.
Hydrometrics, Inc. August 1993. Asarco Tacoma Plant Remedial Investigation, Tacoma,
Washington.
Hydrometrics, Inc. April 1999. Group 5 Technical Memorandum, Asarco
Sediment/Groundwater Task Force.
Hydrometrics, Inc. March 2000. Draft September 1999 Data and Annual Report Long-Term
Remedial Action Monitoring Plan, Asarco Tacoma Smelter.
Hydrometrics, Inc. June 2000. Historical Summary of the Evaluation of Groundwater Remedial
Alternatives, Asarco Tacoma Smelter Site.
Kleinfelder, December 1992. On-Property Baseline Human Health Risk Assessment, Asarco
Tacoma Plant, Tacoma, Washington.
Merrit+Pardini/Sasaki Associates, August 1997. Asarco Ruston/Tacoma Smelter Site, Master
Development Plan, Stakeholder Approval Draft.
Parametrix, 1987. Asarco Tacoma Smelter Remedial Investigation. Unpublished report to
Asarco, Inc., and EPA. Prepared in association with Hart Crowser, TRC, and ETI.
Parametrix, 1989. Asarco Tacoma Smelter Offshore Marine Sediments Feasibility Study.
Parametrix, 1990. Asarco Tacoma Smelter Offshore Feasibility Study, Supplemental Marine
Sediment Survey.
Parametrix, 1991. Asarco Tacoma Smelter Marine Sediment Survey, Supplemental Marine
Sediment Survey.
Parametrix, 1993. Asarco Tacoma Smelter Marine Survey, Yacht Basin Survey Results.
Parametrix, March 1995. Draft Disposal Site Inventory.
Parametrix, April 1996. Phase 1 Data Evaluation Report and Phase 2 Sampling and Analysis
Approach, Asarco Sediments Superfund Site, Expanded Remedial Investigation and
Feasibility Study.
Parametrix, December 1996. Phase 2 Refinement of Options Report, Asarco Sediments Superfund
Site, Expanded Remedial Investigation and Feasibility Study.
R-1
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REFERENCES
Parametrix, June 1999. Copper in Nearshore Marine Water Technical Memorandum.
Parametrix, January 2000a. Refinement of the Proposed Remedy Report (as amended by EPA
letter of March 14, 2000).
Parametrix, January 2000b. Documentation of the Feasibility Study Process for the
Sediments Portion of the Asarco Sediments Operable Unit
Parametrix, February 2000. Asarco Sediments Superfund Site Thin-Layer Cap Pilot Project Year 2
Monitoring Report.
Parametrix, May 2000. Draft Biological Assessment.
Roy F. Weston, Inc., October 1993. Supplemental Feasibility Study, Commencement Bay
Nearshore/Tideflats Asarco Sediments Site.
Roy F. Weston, Inc., October 1996. Ecological Risk Assessment and Seafood Consumption
Screening Risk Assessment.
United States Environmental Protection Agency (EPA), September 1989. Commencement
Bay Nearshore/Tideflats Record of Decision.
EPA, April 1993. Remedial Action Objectives and Preliminary Remediation Goals for the
Asarco Tacoma Site.
EPA, March 1995. Asarco Tacoma Smelter and Breakwater Peninsula ROD.
EPA, October 1995. EPA Region III Risk-Based Concentration Table.
EPA, July 1999. A Guide to Preparing Superfund Proposed Plans, Records of Decision, and Other
Remedy Selection Decision Documents.
EPA, November 1999. United States vs. Asarco, Inc., Commencement Bay
Nearshore/Tideflats Superfund Site, Asarco Sites, Modification Agreement, Civil
Action No. C91-5528 B, Civil Action No. C94-5714, Docket No. 10-94-0221. Signed by
EPA and Asarco.
EPA, January 2000a. Documentation of the Feasibility Study Process for the Sediments
Portion of the Asarco Sediments Operable Unit.
EPA, January 2000b. Proposed Plan, Asarco Sediments/Groundwater Operable Unit 06 Ruston and
Tacoma, Washington.
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Tables
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TABLE 5-1
Maximum Metal Concentration in Sediment
Contaminant Max Concentration (mg/kg) Percentage of Detections > CSLs
As 26,410 53
Cu 43,840 42
Pb 22,450 32
Zn 174,000 39
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TABLE 9-1
Groundwater Alternatives
Estimated Cost
(in millions $)3
Alternative 1
Description 2
Capital
Annual
O&M
30-Year
O&M
Total
Present
Worth
GW-A: No Action
No actions are taken.
$0
NA
$0
$0
GW-B: Source Control, Soil
Capping and Surface Water
Controls, Groundwater
Interception/Treatment,
Replacements of Leaking
Subsurface Water Lines,
Institutional Controls and
Monitoring.
Reduce groundwater discharge to Commencement Bay by 1) limiting infiltration of
precipitation and surface water, 2) intercepting groundwater at selected locations
before it enters the Facility and treating* that groundwater as required prior to
discharge to Commencement Bay, and 3) abandoning or replacing leaking
underground sewer and water lines. Continued groundwater monitoring and
implementation of institutional controls (e.g., restricting future use of Facility
groundwater) will also occur. If groundwater cleanup goals are not achieved,
contingency actions such as additional diversion, may be constructed.
"Captured groundwater will be directed to the on-site stormwater treatment system
being constructed as part of the upland, OU02 remedy. This treatment system
includes particulates removal enhanced by the use of coagulants and flocculants.
$0
$0.1
$1.8
$1.8
GW-C: Pump/Treat and
Discharge to Outfalls
Actively remove contaminated groundwater by a series of extraction wells. The
groundwater would be treated and discharged to Commencement Bay. Candidate
areas for the pump/treat alternative are downgradient of the Arsenic Kitchen,
Southeast Plant (DMA) area, Copper Refinery, and Fine Ore Bins. All elements of
Alternative GW-B (above) would be included to reduce groundwater discharge to
Commencement Bay, protect the deep aquifer, and provide institutional controls.
$28.7
$0.6
$9.1
$37.8
GW-D: In situ Groundwater
Treatment
In situ oxidation of groundwater by air injection to enhance chemical precipitation
of arsenic. Nutrient injection would stimulate biological degradation of DMA-related
compounds in the Southeast Plant Area. All elements of Alternative GW-B (above)
would be included to reduce groundwater discharge to Commencement Bay,
protect the deep aquifer, and provide institutional controls.
$2.0
$0.1
$2.3
$4.3
1 of 2
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TABLE 9-1
Groundwater Alternatives
Estimated Cost
(in millions $)3
Total
Annual 30-Year Present
Alternative1 Description2 Capital O&M O&M Worth
GW-E: In situ Treatment by Injection of seawater to raise pH and provide a more oxygenated subsurface $2.2 $0.1 $2.2 $4.4
Seawater Injection environment conducive to chemical precipitation of arsenic. Candidate areas for
seawater injection are the Arsenic Kitchen, Southeast Plant (DMA) area, and Fine
Ore Bins. All elements of Alternative GW-B (above) would be included to reduce
groundwater discharge to Commencement Bay, protect the deep aquifer, and
provide institutional controls.
Notes:
1) Alternatives GW-1B and GW-3D from the 1993 FS are not addressed in this ROD because soil remedial actions selected previously by EPA have eliminated these
alternatives as options. Alternative GW-A, "no action," is retained only for comparative analysis purposes.
2) Although not specifically listed, it is assumed that all alternatives listed this table would be implemented in addition to the selected remedy for OU 02 (i.e., source
control, surface water and groundwater diversions, site capping and other OU 02 remedy elements are required in addition to the OU 06 groundwater alternatives listed in
this table). The cost for the OU 02 remedy is excluded from the estimated cost shown in this table.
3) Present worth operation and maintenance (O&M) costs assume a 5 percent discount rate over 30-year period.
2 of 2
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TABLE 9-2
Sediment Remedial Alternatives for the Nearshore/Offshore Area
(88,000 yd2 or 18 acres)
Estimated Cost
(in millions $)1
Alternative
Description
Capital
O&M
Total
Present
Worth
S-1A: No Action
No actions are taken.
$0
$0
$0
S-1B: Natural Recovery
Natural recovery does not involve any active work, but typically includes long-term
monitoring to ensure that sediment quality is naturally improving over time (e.g., new
clean sediment is covering up the contaminated sediment).
$0
$0.2
$0.2
S-1C: Capping
Cover 88,000 yd2 ( 18 acres) of contaminated sediment with a minimum of 3 ft. of
clean sand and gravel. In general, the purpose of a cap is to prevent the direct
contact of people and marine organisms with contaminated sediment.
$10.3
$1.3
$11.6
S-1D: Dredging and Nearshore
Confinement
Dredge contaminated sediment and place in nearshore confined aquatic disposal
(CAD) facility, which is an underwater cell that keeps the contaminated sediment
covered with a cap and isolated from the overlying water. This alternative would
require dredging of a minimum of 70,000 yd3 of contaminated sediment with a dredge
depth of approximately 1 yd (some of the 88,000 yd2 or 18 acres of contaminated
sediment would be covered by the nearshore facility), placement of the dredged
sediment within a berm along the shoreline of the Facility, and placement of a clean
sediment cap over the dredged material. The cap and containment berm of the
nearshore CAD would be armored to minimize erosion.
$11.8
$1.0
$12.8
S-1E: Dredging and Upland
Disposal
Dredge a minimum of 88,000 yd3 of contaminated sediment with a dredge depth of
approximately 1 yd; placement of the dredged sediment at an off-site location.
$26.0
$0.2
$26.2
Notes:
1) A discount rate has not been applied to the capital costs because the remedy will be implemented within a short period of time (5 years). Operations and maintenance
(O&M) costs are for 20 years.
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TABLE 9-3
Sediment Remedial Alternatives for the Yacht Basin (75,000 square yards; 15.5 acres)
Estimated Cost
(in millions $)1
Alternative
Description
Capital
O&M
Total
Present
Worth
S-2A: No Action
No actions are taken.
$0
$0
$0
S-2B: Natural Recovery
Natural recovery does not involve any active work, but typically includes long-term
monitoring to ensure that sediment quality is naturally improving over time (e.g., new
clean sediment is covering up the contaminated sediment).
$0
$0.3
$0.3
S-2C: Dredging and Nearshore
Confinement
Dredge contaminated sediment and place in nearshore CAD. This alternative would
require dredging of approximately 55,000 yd3 of contaminated sediment, with a
dredge depth of approximately 2 feet.
$4.9
$0.2
$5.1
S-2D: Dredging and Upland
Disposal
Dredge an area of 75,000 yd2 (15.5 acres) of contaminated sediment to a depth of
2 feet and place beneath the upland cap in the central portion of the upland part of
the Facility. This alternative would require dredging of approximately 55,000 yd3of
contaminated sediment. (Note: As a contingency, if all the contaminated material
cannot be removed from the Yacht Basin, dredging in the Basin followed by
placement of clean material may occur.)
$3.4
$0.2
$3.6
Notes:
1) A discount rate has not been applied to the capital costs because the remedy will be implemented within a short period of time (5 years). Operations and maintenance
(O&M) costs are for 20 years.
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TABLE 9-4
Sediment Remedial Alternatives for the Northshore Area (7,000 square yards; 1.5 acres)
Estimated Cost
(in millions $)1
Alternative
Description
Capital
O&M
Total
Present
Worth
S-3A: No Action
No actions are taken.
$0
$0
$0
S-3B: Natural Recovery
Natural recovery would not involve any active work at the Facility, but would include
monitoring to ensure that sediment quality is naturally improving over time (e.g., new
clean sediment is covering up the contaminated sediment).
$0
$0.2
$0.2
S-3C: Capping
Cover 7,000 yd2 (1.5 acres) of contaminated sediment with a minimum of 1.0 m of
clean sand and gravel. In general, the purpose of a cap is to prevent the direct
contact of people and marine organisms with contaminated sediment.
$0.5
$0.2
$0.7
S-3D: Dredging and Nearshore
Confinement
Dredge contaminated sediment and place in nearshore CAD. This alternative would
require dredging of approximately 4,500 yd3 of contaminated sediment (7000 yd2
dredged to a depth of 2 feet).
$0.7
$0.2
$0.9
S-3E: Dredging and Upland
Disposal
Dredge contaminated sediment and place beneath the upland cap. This alternative
would require dredging of approximately 4,500 yd3 of contaminated sediment
(7000 yd dredged to a depth of 2 feet).
$0.5
$0.2
$0.7
Notes:
1) A discount rate has not been applied to the capital costs because the remedy will be implemented within a short period of time (5 years). Operations and maintenance
(O&M) costs are for 20 years.
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TABLE 12-1
Groundwater Cleanup Levels
Cleanup Level
Constituent (H9"-) Basis
Shallow Aquifer System1
Arsenic 6
Copper 3.1
Deep Aquifer
Metals MCLs Maximum contaminant levels; 40 C.F.R. Part 141.62
1 Includes the slag, marine sand, and intermediate aquifers as referenced in various Site documents.
2 The regional background concentration for copper in groundwater has been established at 40 |jg/L; 3.1 |jg/L
will be the targeted cleanup level to be achieved through dilution within marine waters that mix with groundwater
in the nearshore areas of the Facility aquifers.
Background concentration in regional groundwater
Marine chronic criteria; WAC 173-201A-0402
TABLE 12-2
Sediment Cleanup Levels for Marine Sediments at OU 06
Remedy Unit
Type of Remedy
Remediation Cleanup
Level
Monitoring Cleanup
Level
Nearshore/Offshore and Capping
Northshore Areas
Preponderance-of-Evidence
Approach1
Washington State
Sediment Management
Standards - SQS (WAC
173-340-320)
Yacht Basin
Arsenic2
2
Copper
Lead3
Zinc
Dredging
93 mg/kg
390 mg/kg
450 mg/kg
410 mg/kg
93 mg/kg
390 mg/kg
450 mg/kg
410 mg/kg
Moderate Impact Zone and Monitoring
Contaminant Effects Areas
Preponderance-of-Evidence
Approach1
Preponderance-of-
Evidence Approach1
See Section 7.2.2.
CSL; (WAC 173-204-520)
1 SQS; (WAC 173-204-320)
-------
This page is intentionally blank.
-------
Figures
-------
This page is intentionally blank.
-------
o
o
<
o
CO
CO
CO
CQ
Maury Island
NORTH
Approx Scale: 1" = 4000'
PugetSound
BREAKWATER PENINSULA
PLANT SITE
Commencement Bay
EXPLANATION
Operable Unit 06 of Commencement Bay
Near Shore Tideflats Superfund Site
(Includes Groundwater Beneath OU 02)
Operable Unit 02 of Commencement Bay
S2SS3 Near Shore Tideflats Superfund Site
Figure 1-1
Asarco Facility Location Map
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Fig 1-1 Asarco Facility Location Map . gr
-------
-100
-80
-60
-40
Point
Defiance
Commencement
Bay
Breakwater
Peninsula
Ferry
Terminal
Tacoma
Yacht
Club
Yacht'
Basin
Ruston
Town
Limits
Asarco
Smelter,
Upland
OU 02
Asarco Sediments/
Groundwater OU 06
(Includes groundwater
beneath OU 02)
•S8
EXPLANATION
Asarco Sediments/Groundwater OU 06
(Includes Groundwater Beneath OU 02)
Asarco Upland OU 02
(Excludes Underlying Groundwater)
Ruston Way
- -20 - Water Depth in Meters
0 0.2 0.4
Scale in Kilometers
152679.PR.02_E062000009SEA. Fig 1-2 Site Location . 6-21-00 dk/gr
Figure 1-2
Operable Unit 06 Site Boundary
Asarco Sediments/Groundwater OU 06 ROD
-------
COMMENCEMENT BAY
Figure 1-3
Former Facility Layout
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 1-3 Asarco Tacoma Smelter Site Former Facility Layout. 6-21-00 . gr
-------
Silt and Clay
A'
::Cteep:^ciifer:$ijs&m::
NOT TO SCALE
EXPLANATION
__y__
Water Level
Groundwater Flow Direction
Figure 1-4
Conceptual Cross Section
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Fig 1-4 Conceptual Cross Section . 6-21-00 . dk/gr
-------
COMMENCEMENT
BAY
it ~;
Vy MAUAW
U'\
y Reference Areas
VASHON ISLAND ^3
/7VN US
VN7 N
SCALE IN MILES
I U I
0 1/2 1
\ PRCJECT SITE
i
REF-4B • j<
\v
N.
REF"2 * ft; BROWNS PT.
V
x\ \
COMMENCEMENT
V'
BAY
urJ
SCALE IN FEET
0 400 800
v- 50 Depth (in feat)
3 Transect Numbers
° Previously Sampled Stations
~ 1994 Stations
Coarse Habitat
Sand Habitat
Y///A Mud Habitat
Source: Parametrix, Inc., April 1996.
Figure 1-5
Habitat Areas Defined by
Benthic Infauna Sampling
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 1-5 Hab Habitat Areas Defined by Benthic Infauna Sampling . 6-20-00 . gr
-------
Figure 5-1 1 of 2
Source Areas and Selected
Remedy for Operable Unit 06
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA. Fig 5-1 1of2 Source Areas Selected Groundwater Remedy . 6-21-00 . gr
-------
Expanded View of Figure 5-1 1 of 2 Inset
A
EXCAVATED iiOl/KCE AX£A HLL
U^'KKyiON DrTQC
IV u^it
KLI 4 Oil
UteJ-TVM
-RAILROAD TUKKEL
-AUTO TUNN'n.
DRAINAGE BLANKET
KEI'UCEMEST OF 30" SEWSR UNE
"AND 15' VATER UAIN
ALONC KUSTOK VAV
^-kversion Drrai prkcipttatton
SURFACE *ATER DRAINAGE
10* nnoo^ujiUTY
SILT ASOTARD
-GROUNDWATER HORIZONTAL
INTERCEPTION oruks
.site cap piKvnsrs
TO
/ KTILTKAT10S
/ GKOUNTATEK
POST-ftA GROUND SURFACE
KEPUCSMEST OUTKAIJ.
SYS7EM EQUIPPED WITH
TKKATVKNT IT.ATVK15S
A'
1£W PERirKABlUTY
SU.T ASvTTARD
GRCVNDWATEH !T/>W AFTER:
• source area son.'; rewova:. upland
• GROUNDWATER ru>«r CNTSRCWTEO
• surface no* uivKirrEo
• OVTTALL SYSTEM REPLACED
• LEAXY PIPES REPLACED
• caI' prevektinc infiltration
O" PRECIPITATION
POST-RA GROUNDWATER KIXJW AND DISCHARGE
COMMKKCKUK.VT HAY
(ij>ckzxg Nflimnrx.Tr)
HOT TY> IKUUC
StAC FACK
SMOKEUtfK
PROTECTION
rRrc :• it atk r/ ska * a tze
TTUS^mOS' ZOKK
X-ZOKE Of* TIDAL
KXPIAN<;>: INTO oLAG
- NKT CROUKDVaTJIR
rsAVFJ. cistas'-o:
Source: Hydrometrics, inc.
Figure 5-1 2 of 2
Source Areas and Selected
Remedy for Operable Unit 06
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA. Fig 5-1 2of2 Source Areas Selected Groundwater Remedy . 6-21-00 . gr
-------
SCALE
(In Feet)
J WELL
aSEAS-2
OUTFALL LOCATION
SOURCE AREAS
LONG TERM MONITORING WELL (SLAG AQUIFER)
LONG TERM MONITORING WELL (INTERMEDIATE AQUIFER)
LONG TERM MONITORING WELL (DEEP AQUIFER) SAMPLED ANNUALLY
SHORELINE MONITORING STATION LOCATION
PRODUCTION WELL (ABANDONED DEC. 1994)
SEAWATER MONITORING STATION
TIDE GAGE
SITE DEVELOPMENT BOUNDARY
NOTE:
1. WELL LOCATIONS REFERENCE TO NAD 8391
ASARCO INCORPORATED
SEPTEMBER 1999 DATA & ANNUAL REPORT
LONG-TERM REMEDIAL ACTION MONITORING
TACOMA. WASHINGTON
Source: Hydrometrics, inc., March 2000.
Figure 5-2
Monitoring Well Locations
Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 5-2 Monitoring Well Locations and Source Areas . 6-21-00 . gr
-------
SCALE
| | SOURCE AREAS
• MW-28 LONG TERM MONITORING WELL (SLAG AQUIFER)
aSMS-1 SHORELINE MONITORING STATION LOCATION
a SEAS—2 SEAWATER MONITORING STATION
<0.005 DISSOLVED ARSENIC CONCENTRATION (MG/L)
^ . INFERRED ISOCONCENTRATION CONTOUE
^ (DASHED WHERE APPROXIMATE)
NO MEASUREMENT. TECHNICAL DIFFICULTIES
NOTES:
1. WELL LOCATIONS REFERENCE TO NAD 8391
2. Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
ASARCO INCORPORATED
SEPTEMBER 1999 DATA & ANNUAL REPORT
XNG-TERM REMEDIAL ACTION MONITORINC
TACOMA, WASHINGTON
Source: HydroMetrics, inc., March 2000.
Figure 5-3
Slag Wells
Dissolved Arsenic in Groundwater
September 1999
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA . Fig 5-3 Slag Wells Dissolved Arsenic in Groundwater Sept 1999 . 6-21-00 . gr
-------
| | SOURCE AREAS
• MW-103 LONG TERM MONITORING WELL (INTERMEDIATE AQUIFER)
<0.005 DISSOLVED ARSENIC CONCENTRATION (MG/L)
^ INFERRED ISOCONCENTRATION CONTOUR
^ (DASHED WHERE APPROXIMATE)
NO MEASUREMENT, TECHNICAL DIFFICULTIES
NOTES:
1. WELL LOCATIONS REFERENCE TO NAD 8391
2. Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
ASARCO INCORPORATED
SEPTEMBER 1999 DATA & ANNUAL REPORT
.ONG-TERM REMEDIAL ACTION MONITORING
TACOMA, WASHINGTON
Source: HydroMetrics, inc., March 2000.
Figure 5-4
Intermediate Wells
Dissolved Arsenic in Groundwater
September 1999
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA . Fig 5-4 Intermediate Wells Dissolved Arsenic in Groundwater Sept 1999 . 6-21-00 . gr
-------
SCALE
{In Peet)
| | SOURCE AREAS
• WW-28 LONG TERM MONITORING WELL (SLAG AQUIFER)
aSMS-1 SHORELINE MONITORING STATION LOCATION
a SEAS—2 SEAWATER MONITORING STATION
<0.005 DISSOLVED COPPER CONCENTRATION (MG/L)
INFERRED ISOCONCENTRATION CONTOUR
(DASHED WHERE APPROXIMATE)
NO MEASUREMENT, TECHNICAL DIFFICULTIES
NOTES:
1. WELL LOCATIONS REFERENCE TO NAD 0391
2. Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
ASARCO INCORPORATED
SEPTEMBER 1999 DATA & ANNUAL REPORT
LONG-TERM REMEDIAL ACTION MONITORING
TACOMA, WASHINGTON
Source: HydroMetrics, inc., March 2000.
Figure 5-5
Slag Wells
Dissolved Copper in Groundwater
September 1999
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA . Fig 5-5 Slag Wells Dissolved Copper in Groundwater Sept 1999 . 6-21-00 . gr
-------
SCALE
(In Feet)
| | SOURCE AREAS
• MW-1Q3 LONG TERM MONITORING WELL (INTERMEDIATE AQUIFER)
<0.002 DISSOLVED COPPER CONCENTRATION (MG/L)
^ INFERRED ISOCONCENTRATION CONTOUR
^ (DASHED WHERE APPROXIMATE)
NO MEASUREMENT, TECHNICAL DIFFICULTIES
NOTES
WELL LOCATIONS REFERENCE TO NAD 8391
Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
ASARCO INCORPORATED
SEPTEMBER 1999 DATA 8c ANNUAL REPORT
LONG -TERM REMEDIAL ACTION MONITORING
TACOMA. WASHINGTON
Source: HydroMetrics, inc., March 2000.
Figure 5-6
Intermediate Wells
Dissolved Copper in Groundwater
September 1999
Asarco Sediments/Groundwater OU 06 ROD
152679. PR.02_E062000009SEA . Fig 5-6 Intermediate Wells Dissolved Copper in Groundwater Sept 1999 . 6-21-00 . gr
-------
Dissolved Arsenic
40.000
10.000
7.000
4.000
1.000
0.701
~ 0.401
73
CO
<
CJ)
E
0.101
0.071
0.041
8:869
0.004
is
1
t:
COaotcoa)i-ON ca i T T m V V *7 ^ V cq>>t—cs,c^,c^>c'3
55 >>11? 5 5 5 5 5
5 5
2 2
5 5 5 5 5
2 5 2 2 2
95%
5%
CD Median; 75%
25%
o Outliers
Site Code
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/Lx 1,000 = 100 g/L).
152679.PR.02_E062000009SEA. Fig 5-7 Box Plots for Arsenic Copper Slag Wells . 6-20-00 . gr
Figure 5-7
Box Plots for Arsenic
and Copper, Slag Wells
Asarco Sediments/Groundwater OU 06 ROD
-------
Dissolved Arsenic
60.000
30.000
19:888
4.000
.<2 3
% &
0.500
0.200
0.090
0.060
0.030
8 m
0.004
mm.
in! i
¦fli >i
St
l-
plilllliliillllllglllBllll
—.—
?££»» ||>»»>»»»»^
Site Code
Dissolv/ed Copper
30.000
19:888
4.000
73
¦—• D)
a £
0.500
0.200
0.090
0.060
0.030
8:8a?
0.004
0.001
fill
:l':i
I
:h:
i
ill
O
' ' ' ¦ '
2 2
ZEZ 95%
5%
CD Median; 75%
25%
o Outliers
* Extremes
O CO «f CO
-------
MW-139A
o>
E
0.26
0.22
0.18
0.14
0.10
0.06
0.02
-0.02
o
D
*
K
. . .
C
»
0
O o
:* * *
m "OQn
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o : /*
T— 7—
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co caocoh-
oo
CD
CD cd
CD CD
CD
CD
CD OIDCDCD
CD
CD
CD
CD CD
CD CD
CD
CD
CD OIDCDCD
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CD
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r— T—
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T—
§ £
C Q.
3 CD
->
-------
COMMENCEMENT
BAY
o9
o8
o?
& 'i
\v, MAUFiYiJ
^^siANDy Reference Areas
VASHON ISLAND
PlFh
0 1/2 1
SITE
i
COMMENCEMENT
BAY
17 175 18
ASARCO
SMELTER
Note: All numbers and locations of samples are approximate.
EXPLANATION
-Sflh' Depth (in feet)
3 Transect Number
SCALE IN FEET
|—j | 1 o Surface Sediment Sample Location
o 300 soo ~ Subsurface Sediment Sample Location
Source: Parametrix, Inc., April 1996.
Figure 5-10
Sediment Station Locations
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 5-10 Sediment Station Locations . 6-20-00 . gr
-------
COMMENCEMENT
BAY
Note: Previously sampled station results are from
-so ^Depth (in feet)
3 Transect Number
1978, 1990, and 1991
Previously Sampled Station - Exceeds
SedimentQuality Standards (SQS)
¦ 1994 Station - Exceeds SQS
* One or Two Organics Exceed SQS
SCALE IN FEET
n_r
. Previously Sampled Station - Exceeds
Previously Sampled Station ~ Cleanup Screening Level (CSL)
400 800
o 1994 Station
+• 1994 Station - Exceeds CSL
Source: Parametrix, Inc., April 1996.
Figure 5-11
Sediment Chemistry Comparison
to State SMS Criteria
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 5-11 Sediment Chemistry Comparison to State SMS Criteria . 6-20-00 . gr
-------
3Sq -
COMMENCEMENT
BAY
0
0
0
\
\
\
y''
/ /°
0
o
~
s /
°
0
0
/
....—"-*¦
yS Q
X
O O o
0
y /~\ \
E E
E "
14 15 15.5 16
ASARCO
SMELTER
16.5
17 175
18.5 19
20
Note: Borders do not define specific areas associated with each station.
-so - v Depth (in feet)
3 Transect Number
SCALE IN FEET
One Bioassay Exceeding Criteria
Exceeds Amphipod Criteria
400 800
Previously Sampled Station + Two Bioassays Exceeding Criteria E Exceeds Echinodem Criteria
1994 Station ffl Three Bioassays Exceeding Criteria N Exceeds Neanthes Criteria
Source: Parametrix, Inc., April 1996.
Figure 5-12
Summary of Bioassay Results That
Exceed One or More State SMS Criteria
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 5-12 Summary of Bioassay Results That Exceed One or More State SMS Criteria . 6-20-00 . gr
-------
Smelter Contaminant
Effects Area
EXPLANATION
50 Depth (in feet)
3 Transect Number
o Previously Sampled Station
~ 1994 Station
I | Contaminant Effects Area
IMPACT CATEGORIES
A No Current Impacts / Future Impacts Not Predicted
B No Known Current Impacts / Future Impacts Possible
C Current Minimal Impacts (Cause Uncertain) / Future Impacts Possible
D Current Minimal Impacts (Sediment Related) / Future Impacts Possible
E Current Moderate to Severe Impacts / Future Impacts Probable
Note: Figure adapted from Parametrix, 1995.
Figure 7-1
Cleanup Level Evaluation Areas
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA . Fig 7-1 Cleanup Level Evaluation Areas OU 06 . 6-21-00 . gr
-------
-------
-------
-------
APPENDIX A
Trend Plots of DMA-Related Organic
Compounds
-------
This page is intentionally blank.
-------
1000
100
U)
£
0.01
0.001
0.0001
CO
o
CO
o
s
0
5
a
$
o
5
a
Si
Sample Date
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
B-37
-m MW-107
MW-110
-K MW-111
-e MW-1A
• • • -Post-RI DL
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA. Fig A-1 1o13 Aniline Trend Plot. 6-20-00 . gr
Figure A-1 1 of 3
Aniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
U)
£
0.001
0.0001
0.01 it-
o~
i-
o
: - ."T * 4
liiteii^Mpi ii«
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HSaBMM$8&
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-B-16
—¦ MW-112
* MW-113
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Mar-98
8
a
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b
5
a
d
b
5
8
6.
«»
Sample Date
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/Lx 1,000= 100 g/L).
152679.PR.02_E062000009SEA . Fig A-1 2of3 Aniline Trend Plot. 6-20-00 . gr
Figure A-1 2 of 3
Aniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
0.1
U)
£ 0.01 -
„ . •*>»•
. ' -H--. '•
*- U"\,i v-"' --
. , . i. ..,t; : • ,
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-* MW-201
Hi MW-204
-A—MW-205
-*—SMS-2
- - - -Post-RI DL
0.001 it
'At'?I. ¦
,f • I' ' ~ V
0.0001
a
$
Cl
St
a
$
o-
6
8
a
Si
o
5
a
Si
&
a
Si
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-1 3of3 Aniline Trend Plot. 6-20-00 . gr
Figure A-1 3 of 3
Aniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
10°
0.000]
U*)
o
o
o
o
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o
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o
>-
O
2
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Si
a
5
•o
o
o
o
CO
O
00
O
6.
b
6.
6.
2
Si
5
$
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower {see Data Validation Report, Appendix B).
b
&
&
$
-4 B-37
Hi MW-107
-Jk MW-110
-* MW-111
-e—MW-1A
Post-RI DL
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-2 1of3 N N-Dimethylaniline Trend Plot. 6-20-00 . gr
Figure A-2 1 of 3
N, N-Dimethylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
5 ' 'i < ' ;
•"j <, ¦
< >
" *•' !'' ft'W'Jsf - ,>*lv's- 1
. i ,11 ?„iv; t',*'' •, *
. .». . - ,
v?r- - v-'- ,^:Ar/r
-~ B-16
Hi MW-112
-A MW-113
-K MW-1B
-e MW-200
- - - - Post-RI DL
-, ./TT
• ' I ti' MM
- , • *u < \ax ¦¦
0.0001
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uo
o
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=>
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b
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a
$
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b
o
d
$
oo
<>
b.
2
03
O
d
Si
§
b
8:
a
Si
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-2 2of3 N N-Dimethylaniline Trend Plot. 6-20-00 . gr
Figure A-2 2 of 3
N, N-Dimethylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
0.1
O) 0.01
E
0.001 it
0.0001
, /
^4hA *
* f5 ' .
?>
| * t >
' <> 11 • . »
¦ - '>'-,r,
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i ' , '',<' "H.' ,v'
* r, • -
->. ,¦
;,v,' *
• '¦;
i
-4 MW-201
-¦ MW-204
-A MW-205
-* SMS-2
Post-RI DL
o
§
LO
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O
c
a
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—1
2
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2
&
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-2 3of3 N N-Dimethylaniline Trend Plot. 6-20-00 . gr
Figure A-2 3 of 3
N, N-Dimethylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
IUU
U)
£
0.0001
0.01 -
0.001
>•
o
-4 B-37
Hi MW-107
-k MW-110
-K MW-111
-e MW-1A
Post-RI DL
o
O
Q.
o
m
o
<>
<>
o
o
r-*
<>
r«s
O
59
<>
OO
o
8
&
o
6.
o
Q.
o
Q.
6
6.
$
2
$
Si
2
$
2
Si
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/Lx 1,000= 100 g/L).
152679.PR.02_E062000009SEA . FigA-3 1of3 N-Methylaniline Trend Plot. 6-20-00 . gr
Figure A-3 1 of 3
N-Methylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
0.0001
<>
>-
o
«. ' ' » " ' "t-t ;>.1«'< ', V ,<"1
*", -*. V"* - •¦. :,¦ •-
¦ > 1"'- *j ^ ¦', -
¦ ' :,Ir.:;v-, ""•
'. • • i-,,.-^,: •-• -
it j£ --
,t,-, f
^s—« - '* s*-
¦
o
t
O
c
D
6.
o
2
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
WM
ǤM|
\ /
\\ \ :/|f t
...
- , -
'• * -'
<^ra..;
¦
iO
-O
o
rv.
CO
CO
Mar-99
8~
Q.
3t
b
2
&
s
b
2
6.
$
b
2
Q.
&
a
Si
-~ B-16
-»— MW-112
-* MW-113
-* MW-1B
-e MW-200
Post-RI DL
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-3 2of3 N-Methylaniline Trend Plot. 6-20-00 . gr
Figure A-3 2 of 3
N-Methylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
1 r
-• MW-201
Hi MW-204
-* MW-205
-*—SMS-2
• - • -Post-RI DL
0.0001
c
o
a
Si
a
si
&
o
o
o
CO
o
CO
o-
8
o
o
a
a
&
a
3i
$
5
$
2
NOTE: The typical detection limit is shown. However, the detection limit
was occasionally higher or lower (see Data Validation Report, Appendix B).
Source: Hydrometrics, Inc., March 2000.
NOTE: Concentrations shown in this figure are expressed in mg/L
(milligrams per liter). Concentrations cited in the text are expressed
in g/L (micrograms per liter). Multiply mg/L by 1,000 to convert
to g/L (e.g., 0.100 mg/L x 1,000 = 100 g/L).
152679.PR.02_E062000009SEA . Fig A-3 3of3 N-Methylaniline Trend Plot. 6-20-00 . gr
Figure A-3 3 of 3
N-Methylaniline Trend Plot
Asarco Sediments/Groundwater OU 06 ROD
-------
APPENDIX B
Summary of Sediment Sampling Results
-------
This page is intentionally blank.
-------
Station
Year
As
Cu
Pb
Hg
Zn
1-1
1987a
23
60
52
ND
118
1988
19
50
33
0.275J
68
2-1
1987a
320*
218
251
ND
850*
1988
30
120
65
0.735J*
110
2-2
1987®
240*
147
158
ND
530*
2-3
1987a
70*
50
72
ND
223
2-5
1988
27
23
35
0.05J
91
2-6
1988
36J
27J
44J
0.075J
111J
1988D
34J
28J
53J
0.055J
109J
3-1
1987®
1,620*
1,145*
1,805*
ND
6,940*
1987a
555*
381
830*
ND
4,305*
3-2
1988
455*
244
488*
0.14
2,275*
1988D
485*
248
540*
0.17
2,420*
3-3
1987®
170*
290
477*
ND
2,115*
1989"
908*
387
822*
0.13
3,931*
3-4
1988
2,378*
998*
2,600*
0.26J
11,250*
1989b
3,117*
1,259*
3,094*
0.14
11,250*
3-5
1988
1,940*
793*
1,565*
0.28J
6,175*
3-6
1988
1,130*
468*
845*
0.25J
2,725*
4-0
1987®
905*
725*
1,040*
ND
4,630*
1987®
4,915*
3,115*
6,650*
ND
18,000*
4-1
1988
7,300*
3,500*
7,900*
0.2
19,700*
1989b
7,502*
4,080*
7,976*
0.11
25,000*
1987®
6,600*
2,545*
6,100*
ND
1,625*
4-2
1988
7,350*
3,025*
6,725*
0.17
17,625*
1988D
6,825*
2,925*
6,200*
0.14
16,825*
4-3
1987®
4,985*
2,225*
3,785*
ND
11,450*
1989"
6,964*
3,200*
4,501*
0.15
23,350*
4-4
1988
26
20
31
0.09J
95
5-0
1987®
100*
615*
191
ND
990*
1988
86*
805*
243
0.34J
1,200*
See notes on Table B-1 5 of 5.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-1 1 of 5
Summary of Inorganics Data
Measured at the Asarco Sediments
Site During the Asarco RI/FS
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-1 1of5 Summary Inorganics Data Asarco Sediments Site During RIFS . 6-21-00 . gr
-------
Station
Year
As
Cu
Pb
Hg
Zn
5-1
1987a
6,450*
3,245*
5,400*
ND
19,050*
5-2
1987a
8,950*
3,450*
6,650*
ND
1,700*
1990
8,000*
3,800*
6,725*
0.12
21,500*
5-3
1987a
1,400*
800*
1,355*
ND
3,830*
1989b
1,577*
698*
1,257*
0.2
3,432*
5-4
1989b
99*
69
91
0.24
ND
5.5-2
1990
8,050*
3,925*
5,025*
0.06
21,100*
6-0
1987a
85*
725*
145
ND
378
6-1
1987a
8,400*
2,985*
9,400*
ND
20,850*
1988
9,150*
3,375*
9,975*
0.16J
21,800*
1990
9,025*
3,375*
10,300*
0.08
25,250*
6-2
1987a
6,350*
3,260*
5,950*
ND
16,750*
1989b
7,274*
3,736*
6,142*
0.2
ND
1990
7,800*
3,825*
7,675*
0.05
22,350*
6-3
1987a
1,620*
930*
1,630*
ND
4,290*
1988
2,550*
1,203*
2,223*
0.25J
5,800*
1990
3,400*
1,775*
3,400*
0.09
10,650*
6-4
1987a
100*
49
85
ND
202
1989b
91*
63
83
0.15
260
6.5-2
1990
6,825*
3,525*
7,675*
0.08
26,011*
7-1
1987a
3,620*
7,600*
2,450*
ND
5,360*
7-2
1987a
6,700*
3,360*
5,000*
ND
17,900*
1990
6,700*
3,575*
5,150*
0.05
20,675*
7-3
1987a
5,050*
2,535*
4,625*
ND
19,000*
7-4
1987a
100*
64
72
ND
215
7-5
1987a
65*
51
39
ND
117
7-6
1987a
18
35
26
ND
71
7-7
1987a
16
16
26
ND
54
8-1
1987®
4,585*
195
3,540*
ND
12,100*
8-2
1987a
565*
444*
462*
ND
1,285*
1989b
521*
406*
411
0.62*
1,233*
8-3
1987a
320*
163
118
ND
394
See notes on Table B-1 5 of 5.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-1 2 of 5
Summary of Inorganics Data
Measured at the Asarco Sediments
Site During the Asarco RI/FS
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-1 2of5 Summary Inorganics Data Asarco Sediments Site During RIFS . 6-21-00 . gr
-------
Station
Year
As
Cu
Pb
Hg
Zn
1989b
141*
126
104
0.26
329
8-4
1987a
160*
125
105
ND
330
1988
55
70
62
0.19J
143
9-1
1987a
5,950*
8,950*
3,670*
ND
5,450*
9-2
1987®
200*
248
158
ND
355
9-3
1987®
65*
82
52
ND
155
9-4
1987"
29
55
39
ND
92
9-5
1987a
16
36
39
ND
75
9-6
1987®
25
25
32
ND
75
9-7
1987a
12
18
19
ND
62
9-8
1987®
9.5
19
19
ND
58
10-0
1987®
4,105*
18,300*
3,910*
ND
4,080*
10-1
1987®
665*
1,665*
690*
ND
1,010*
1988
590*
1,873*
860*
1.8J*
1,000*
10-2
1987®
170*
243
118
ND
330
1988
95*
152
77
0.6J*
176
1989b
144*
223
113
0.9*
284
10-3
1987®
38
53
39
ND
100
1989
77*
103
65
0.4
159
10-4
1987®
42
58
39
ND
109
11-1
1987®
4,995*
12,600*
3,135*
ND
2,430*
11-2
1987®
410*
1,075*
381
ND
505*
11-3
1987®
55
106
59
ND
100
11-4
1987®
47
80
46
ND
121
11-5
1987®
28
50
39
ND
104
11-6
1987®
21
87
39
ND
92
11-7
1987®
12
19
26
ND
58
1988
13
21
28
ND
55
11-8
1987®
12
20
26
ND
62
11-9
1987®
7.5
15
26
ND
54
See notes on Table B-1 5 of 5.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-1 3 of 5
Summary of Inorganics Data
Measured at the Asarco Sediments
Site During the Asarco RI/FS
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-1 3of5 Summary Inorganics Data Asarco Sediments Site During RIFS . 6-21-00 . gr
-------
Station
Year
As
Cu
Pb
Hg
Zn
12-1
1987a
5,050*
7,650*
4,585*
ND
5,100*
1988
2,355*
8,200*
3,275*
5.6J*
3,975*
12-2
1987a
190*
497*
138
ND
219
1989
123*
371
109
*
00
o
183
12-3
1987a
60*
200
72
ND
151
1989
43
82
40
0.28
76
12-4
1987a
35
60
39
ND
79
12-5
1987®
16
46
46
ND
83
13-1
1987a
2,360*
5,400*
2,510*
ND
1,700*
13-2
1987a
o>
o
152
59
ND
88
13-3
1987a
65*
130
59
ND
121
13-4
1987a
24
47
39
ND
71
13-5
1987a
15
23
26
ND
49
13-6
1987a
33
16
19
ND
41
13-7
1987a
12
17
32
ND
54
13-8
1987a
11
14
19
ND
45
14-1
1987a
11,100*
3,850*
3,405*
ND
7,600*
1989"
14,020*
4,874*
4,069*
35*
2,524*
1987s
160*
306
105
ND
249
14-2
1988
69*
148
59
0.25
141
1989b
71*
154
68
0.34
189
14-3
1987a
35
179
65
ND
134
1988
49
119
46
0.34
122
14-4
1987a
60*
46
39
ND
75
14-5
1987a
29
31
32
ND
71
15-1
1988
20,225*
4,600*
4,430*
5.4*
2,825*
15-2
1987®
290*
300
118
ND
296
15-3
1987a
47
72
46
ND
79
15-4
1987a
30
37
32
ND
71
15-5
1987a
13
32
26
ND
58
16-1
1987®
270*
190
59
ND,
141
1988
48
141
44
0.22J
81
See notes on Table B-1 5 of 5.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-1 4 of 5
Summary of Inorganics Data
Measured at the Asarco Sediments
Site During the Asarco RI/FS
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-1 4of5 Summary Inorganics Data Asarco Sediments Site During RIFS . 6-21-00 . gr
-------
Station
Year
As
Cu
Pb
Hg
Zn
16-2
1987a
75*
57
32
ND
64
1989b
41
58
31
0.22
89
16-3
1987a
26
27
19
ND
46
1989b
29
33
16
0.12
68
16-4
1987a
11
24
13
0.12
68
1988
16
21
19
ND
50
17-1
1987a
210*
910*
217
ND
223
17-2
1987®
39
84
26
ND
46
17-3
1987a
21
52
32
ND
64
17-4
1987a
7
26
19
ND
46
18-1
1987a
65*
295
72
ND
109
1989"
57*
249
71
0.24
112
18-2
1987a
35
71
32
ND
64
1988
33
65
35
0.12J
56
1989"
20
61
23
0.22
82
18-3
1987a
26
38
26
ND
46
1989b
37
44
24
0.18
69
19-1
1987"
26
77
26
ND
37
1989b
15
56
20
0.16
33
19-2
1987a
120*
52
26
ND
41
1989b
28
76
32
0.24
52
20-1
1987a
11
61
13
ND
28
20-2
1987a
20
54
32
ND
41
Notes: All data are in mg/kg.
1987 data are from Arasco Rl Round 1
1988 data are from Arasco Rl Round 2.
1989 data are from the 1990 Supplementary Marine Sediment Survey.
1990 data are from the 1990 Supplementary Marine Sediment Survey.
ND No data are available.
D Duplicate sample
* Exceeds LAETs.
* All As data from the 1987 sampling event where "J" qualified.
b The 1989 data for As, Cu, Pb and Hg are from the "heavy metal" Word Perfect table on the 3rd disk transmitted
by Parametrix through PTI (Disk 3). Data for Zn are the values from Table 1 of Parametrix's 1990 Supplemental
Marine Sediment Survey. For Stations 3-4, 4-1, 10-2 and 14-2 (sampled both in 1988' and 1989), the 89 Zn
values are the differences of the "means" in Table 1 multiplied by two minus the 1988 value.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-1 5 of 5
Summary of Inorganics Data
Measured at the Asarco Sediments
Site During the Asarco RI/FS
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-1 5of5 Summary Inorganics Data Asarco Sediments Site During RIFS . 6-21-00 . gr
-------
Chemical
CSL* SQS**
2-2
2-3
2-3 Dup
2-4
3-1
3-2
3-3
4-2
4-3
5-0
5-0 Dup
5-0.25
Arsenic
93 57
I *l
54
62
51
I 2,063|
1 43^
1 H
| 4,626]
5,205
e
I 154l
e
1 142l
e
I 5,398]
Cadmium
6.7 5.1
0.3 U
0.3 U
0.3 U
0.3 U
3.0
0.8
1.4
1 69l
93]
e
I 71.0)
e
1.0
e
1 80)
Chromium
270 260
34
33
39
149
68
36
42
100
161
28
38
| 290)
e
Copper
390 390
94
e
47
e
52
e
43
e
| uio|
e
211
e
321
e
| 1,883]
e
| 2,542]
1 942l
| 882j
| 3,83 5|
Iron
--
18,190
19,950
19,570
18,740
88,290
33,930
42,090
130,300
168,500
36,870
36,090
179,000
Lead
530 450
106
70
74
90
| 1,755|
417
1 704|
| 3,928]
| 3,586|
e
1 1,763|
e
282
e
I 4,252|
Manganese
..
302
1,037
928
1,141
873
1,096
1,067
2,847
822
195
196
296
Nickel
--
27
31
34
91
44
31
33
64
102
17
18
67
e
Silver
6.1 6.1
0.4 A
0.2 U
0.2 U
0.2 U
2.9
0.4
0.9
1 91l
5.3
2.7
2.5
1 "1
e
Zinc
960 410
346
211
229
228
| 6,073|
| 1,843|
| 3,073|
| 10,580|
I 11,120|
1 1,784)
| 1,556|
| 10,930)
Mercury
0.59 0.41
0.095
e
0.066
e
0.075
e
0.170
e
0.200
e
0.072
e
0.091
e
0.051
e
0.03
e
0.230
e
0.280
e
0.05 U
Chemical
CSL* SQS**
5-0.5
5-1
5-2
5-3
5.5-0
6-2
6.5-0
6.5-1
6.5-2
6.5-3
7-3
7-4.5
Arsenic
93 57
| 6,221|
| 7,219|
e
| 8,023|
e
1 1,740)
e
1 H8|
e
| 6,394
e
1 102l
e-
| 6649|
7,435|
1 !]5I
e
1 98l
e
27
e
Cadmium
6.7 5.1
5.5
1 12-°l
e
1 170l
e
1 5"4
c
0.8
e
| 8.3
e
1.4
c
1 M
U.0|
0.3 Ue
1 93l
e
0.3 Ue
Chromium
270 260
338|
e
158
159
78
35
150
36
| 306|
e
120
41
36
44
Copper
390 390
4,269|
| 3,047|
| 3,655|
1 791l
1 1,041|
| 2,886]
L 1,358|
1 4'3,5I
3,308|
e
80
77
46
Iron
--
153,400
202,700
229,400
65,590
26,580
179,600
18,830
208,600
198,000
22,550
21,940
20,680
Lead
530 450
| 3,721|
| 5,282|
e
| 6,122|
e
| 1,369)
e
280
c
| 5»263j
e
206
e
| 4,122|
7,074|
126
e
276
e
40
e
Manganese
..
220
974
826
922
169
1,853
140
607
1,721
872
657
928»
Nickel
-- . --
107
e
131
128
60
17
128
18
101
e
106
37
31
37
Silver
6.1 6.1
9.0|
[ 66l
1 8-°l
1.8
2.7
1 71l
2.7
1 '3I
17|
0.2 U
0.2 U
0.2 U
Zinc
960 410
10,450|
1 14,730|
I 17, uq
L 3>861l
1 972l
| 14,160|
468
| 13,150|
21,150)
367
300
109
Mercury
0.59 0.41
0.05 U
0.024
e
0.032
e
0.150
e
0.290
e
0.036
e
0.450
e
0.05 U
0.055
e
0.100
e
0.130
e
0.270
e
Source: Parametrix, Inc., April 1996.
NOTES:
Table B-2 1 of 3
1. Results presented in mg/kg dry weight.
Metal Concentrations in Sediment
2. See notes on Table B-2 3 of 3.
(mg/kg dry weight)
Asarco Sediments/Groundwater OU 06 ROD
152679 PR 02_E062000009SEA
. Table B-2 1 of3 Metal Concentrations in Sediment mgkg dry wt
6-20-00 gr
-------
Chemical CSL* SQS*«
7-12
8-1.5
8-2.5
8-3.5
9-1
9-2
9-2.5
10-1.5
10-2
10-2.5
11-0
11-0 Dup
| 3,797|
3,914|
1 250l
260|
44
42
1 9,350|
| 9,228)
37,030
34,780
1 3,450|
| 3,6S0J
733
678
89.0
79
1 500l
1 53 0l
| 3,532|
I 3,279|
| 1.800|
| 1.890)
Arsenic
93
57
5.3
| 7,914j
Cadmium
6.7
5.1
0.3 U
| 10.0|
Chromium
270
260
32
155
Copper
390
390
15 e
1 3^729|
Iron
--
--
14,410
228,600
Lead
530
450
15
| 6,312|
Manganese
--
--
619
1,254
Nickel
--
--
31
105
Silver
6.1
6.1
0.2 U
1 ™l
Zinc
960
410
37
| 19,760|
Mercury
0.59
0.41
0.050 e
0.220
II ^1
0.3
28
192
24,070
196
612
26
0.56 A
69
592
0.099
0.3 U
30
90
20,140
74
605
29
0.2 UA
180
0.110
3l34l|
To]
55
7,261
101,600
2,900|
556
90
I "»
~M95|
| 1.8001
93
0.3 U
26
193
16,590
105
269
'20
1.2 C
225
0.110
45
0.3 U
29
95
16,230
52
354
23
0.57 Ab
125
0.140
Chemical CSL* SQS**
11-2
11-2.5
12-2
12-2.5
13-2
13-2.5
14-1
14-2
14-2.5
14-3.5
15-1
15-2
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Nickel
Silver
Zinc
Mercury
93
6.7
270
390
57
5.1
260
390
530 450
6.1
960
0.59
6.1
410
0.41
52
0.3 U
34
114
14,700
50
248
24
0.70 Cb
110
0.220
43
0.3 U
25
68
69
r~m
14,730
50
265
21
0.80 Ab
107
0.130
0.5
28
276
15,930
115
242
27
1.1 Ab
143
0.140
0.3 U
31
203
13,390
90
319
23
1.1 Cb
158
0.085
43
0.3 U
34
96.0
15,560
40
305
21
0.40 Ab
68
0.027
54
0.3 U
44
184
13,950
70
288
29
1.1 Ab
137
0.300
im
TTo|
13
63
44
"4195]
79,220
"3^T0[
514
45
CM
T500|
0.3 U
29
213
13,730
118
160
20
1.2 C
270
0.190
0.3 U
29
167
13,230
58
202
20
1.2 C
100
0.180
54
0.3 U
41
117
20,330
59
442
33
0.89 Cb
120
0.160
26,410|
Hoj
45
"53651
94,190
4,1501
358
54
~nro|
"Z483|
17.7001
II ^11
0.6
29
383
15,150
160
167
23
2.4 A
307
0.220
Source: Parametrix, Inc., April 1996.
NOTES:
1. Results presented in mg/kg dry weight.
2. See notes on Table B-2 3 of 3.
152679,PR.02_E062000009SEA . Table B-2 2of3 Metal Concentrations in Sediment mgkg dry wt. 6-20-00 . gr
Table B-2 2 of 3
Metal Concentrations in Sediment
(mg/kg dry weight)
Asarco Sediments/Groundwater OU 06 ROD
-------
Chemical
CSL* SQS**
15-2.5
15.5-1
15.5-2
16-0.5
16-1
16-2
16.5-1
16.5-2
17-1
17-1.5
17-2
17.5-1
Arsenic
93
57
52 || 2,400||
1 3031
So
©
831
30
1 230l
56
1 225l
1 *6I
52 [
59j
Cadmium
6.7
5.1
0.30 U
4.0
0.5
1.5
0.3
0.3 U
2.0
0.3 U
1.5
0.6
0.3 U
2.3
Chromium
270
260
27
54
33
32
31
62
41
25
31
28
25
19
Copper
390
390
97 || 2,434||
1 544l
|l 497||
191
63
| 1,066)
178
1 601|
296
149
320
Iron
--
--
13,660
149,100
18,850
45,750
12,020
14,550
17,460
11,486
14,390
12,310
12,120
11,799
Lead
530
450
40
1 1,340|
146
330
77
31
317
65
165
84
73
125
Manganese
--
--
269
559
252
237
180
310
135
163
123
157
185
109
Nickel
--
--
19
105
30
31
22
41
36
19
26
24
20
19
Silver
6.1
6.1
0.90 Cb
14.7|
2.4 A 0.93 AC
0.84
0.20 Ube
4.35
0.92 ACe
1.98
1.01
0.48 AC
0.65 AC
Zinc
960
410
84
1,820]
359
1 4801
166
69
230
79
170
105
104
131
Mercury
0.59
0.41
0.12
2.040|
0.077
0.077
0.170
0.020 U
0.170
0.055
0.092
0.052
0.085
0.050
Chemical
CSL* SQS**
17.5-2
18-2.5
18-3.5
18.5-1
18.5-2
Ref2
Ref3
Ref4B
Arsenic
93
57
26
19.3
26
51
18.3
6
55 e
6.9
Cadmium
6.7
5.1
0.3 U
0.3 U
0.3 U
0.5
0.3 U
0.3 U
0.4
0.3 U
Chromium
270
260
23
22
39
36
35
27
47
20
Copper
390
390
91
41
41
167
51
19
59
11 e
Iron
--
--
9,702
10,820
26,750
11,200
10,850
13,530
16,110
16,290
Lead
530
450
34
24
21
61
26
15
72
5.7
Manganese
--
--
152
199"
414
120
236
138
373
154
Nickel
¦ --
--
19
18
42
27
25
17
26
17
Silver
6.1
6.1
0.36 AC
0.20 U
0.20 U
0.73
0.26 AC
0.59 Ab
0.20 U
0.2 U
Zinc
960
410
46
38
80
68
38
33
223
26
Mercury
0.59
0.41
0.061
0.020 U
0.020 U
0.020
0.027
0.025
0.020 Ue
0.040 e
* Washington State Cleanup Screening Levels
** Washington State Sediment Quality Standards
[ " | Value exceeds SQS
|| || Value exceeds CSL and SQS
U = Undetected at the reported detection limit
A = Indicates value determined by Method of Standard Addition
C = Indicates the correlation coefficient for Method of Standard Addition is less than 0.99S
b = Analyte found in blank
e = Estimated
Source: Parametrix, Inc., April 1996.
NOTE: Results presented in mg/kg dry weight.
152679.PR.02_E062000009SEA . Table B-2 3of3 Metal Concentrations in Sediment mgkg dry wt. 6-20-00 . gr
Table B-2 3 of 3
Metal Concentrations in Sediment
(mg/kg dry weight)
Asarco Sediments/Groundwater OU 06 ROD
-------
Foot 0-1
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Zinc
Mercury
Foot 1-2
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Zinc
Mercury
Foot 2-3
Foot 3-4
Foot 4-5
CSL
93
6.7
270
390
530
6.1
960
0.59
93
6.7
270
390
530
6.1
960
0.59
SQS
57
5.1
260
390
450
6.1
410
0.41
57
5.1
260
390
450
6.1
410
0.41
3-1
5-0
1.0
36
367
4881
20
1.5
470] ["TOT]
0.50
52
~422|
194
29
1.5
1X905] [1390]
0.31
2.5 U
0.5 U
45
18
13
26
1.0 U
57
0.26
5.5-0
43
0.50
54
254
92
29
1.5
~*95]
0.29
8-1
11-0
11-1
12.5-1
14-2
15.5-1
3.8
0.5. U
45
22
25 U
22
1.0 U
48
0.03 U 0.051
Arsenic
93
57
Cadmium
6.7
5,1
Chromium
270
260
Copper
390
390
Lead
530
450
Nickel
--
Silver
6.1
6.1
Zinc
960
410
Mercury
0.59
0.41
"Toool
~n
212
2.6
79
3^63|
Z33
l44|
96
1.0
117
37832]
22]
59
13?7|
1041]
105
63
M27|
2/7571
"303|
118
12
16,740
0.042
7£]
27T72|
3
X4l7|
T6|
203
75
2.5
365
0.33
24,310|
"M97|
174
~88|
4,3391
2.5 U:
0.5 U
42
17
25 U
39
1.0 U
69
0.022
Arsenic
93
57
i 691
12,106]
40 E
67
Cadmium
6.7
5.1
2.4
(—14!
0.5 U
0.5 U
Chromium
270
260
72
54
96
65
Copper
390
390
11,329]
16,397]
86
352
Lead
530
450
l 554|
| 1,798|
33
63
Nickel
--
--
52.0
74
50
75
Silver
6.1
6.1
4
l 25|
1.0 U
2.0
Zinc
960
410
11,296
[TT47j
64
131
Mercury
0.59
0.41
f063
0.03
0.29
L 6,737j
11,008]
([37560]
P27|
| 6,024|
19
1 1,933|
1 y-5|
3.2
!_23
1,0
1 28|
0.5 U
3.5
186
82
99
121
33
39
80
3,514|
2,278]
18,488)
1 443
123,250]
54
| 2,128]
4,755|
986|
[3.568]
223
1 5,278|
31
| 1,323]
97
76
106
73
40
24
88
1 nl
8.5|
1 60l
3.0
1 90|
1.0 U
1 95
] 15,580]
!2,303|
|2,589|
11,028
| 3,522|
82
[ 3,365
0.27
FT7]
1 «l
("33
1 H
0.094
| 8.5
| 7,123]
11,373|
|3,538|
34
110,020]
10
| 1,792|
1 9'5I
3.6
1 "2I
0.5
u
1 70l
0.5 U
4.5
237
54
55
92
80
109
109
3,629|
2,671]
8,383|
117
143,840
32
L 2.37»l
4,821|
1,290]
4,315|
51
122,450
26
| 1,086)
121
69
73
59
70
60
114
1 12!
9.5|
1 65i
2.0
1 240|
1.0 U
1 "1
115,730
3,032j
12,458
123
110,370|
51
I 3,366]
0:21
3.0]
| 8.6!
0.12
1 351
0.14
1 M
2,245
7.5
111
| 1,946]
| 2,023|
121
8.0
| 7,021
1.1
Arsenic
93
57
44
| 1,634|
[ 4,543
Cadmium
6.7
5.1
0.5 U
n
I 16
Chromium
270
260
46
39
106
Copper
390
390
1 64|
|3,467|
3,836)
Lead
530
450
25
1 1,278]
5,268|
Nickel
--
34
46
141
Silver
6.1
6,1
1.0 U
i
1 1
Zinc
960
410
102
11.389|
| 17,400|
Mercury
0.59
0.41
0.04
1 '4
0.1
Note: Recovered core sections did not contain the entire 1 foot section
in some cases. Figure 3-2 indicates recoveries for each sample.
U = Undetected
~\ Indicates that the value exceeds SQS (Sediment Quality Standards).
^|j Indicates that the value exceeds CSL (Cleanup Screening Levels).
Source: Parametrix, inc., December 1996.
NOTE: Results presented in mg/kg dry weight.
152679.PR.02_E062000009SEA. Table B-3 Metals Concentrations Subsurface Sediments mgkg dry wt. 6-20-00 . gr
Table B-3
Metals Concentrations
in Subsurface Sediments
(mg/kg dry weight)
Asarco Sediments/Groundwater OU 06 ROD
-------
Chemicai
CSL SQS
5-0
5.5-0
8-1
9-1
11-0
11-1
12.5-1
14-2
Foot 0-1
Fluorene
79
23
7
*
3 U 3 U
2
5
2
4
U
9 U*
Phenanthrene
480
100
83
*
15
14
9
55
10
16
9 U*
Fluoranthene
1,200
160
191
*
51
40
27
100
11
146
9 U*
Butyl benzyl phthalate
64
4.9
5
U*
3
1 321
1 U
3
U
1
U
4
U
9 U*
Bis(2-ethylhexyl)phthalate
78
47
29
*
61
fr i37ii
2
13
1
4
U
9 U*
Foot 1-2
Fluorene
79
23
11
u*
1
6
3
2
U
1
7 U*
Phenanthrene
480
100
11
u*
7
23
38
2
u
5
7 U*
Fluoranthene
1,200
160
11
u*
15
48
85
2
u
43
7 U»
Butyl benzyl phthalate
64
4.9
11
u»
2
C3
3
U
3
1
7 U»
Bis (2-ethylhexyl) phthalate
78
47
11
u*
14
18
4
2
u
14
7 U*
Foot 2-3
Fluorene
79
23
5 U*
3
32
12
*
11 U»
Phenanthrene
480
100
15 *
16
184
119
*
11 U'
Fluoranthene
1,200
160
27 *
51
237
181
*
11 u»
Butyl benzyl phthalate
64
4.9
5 *
3 U
7
U
7
u*
11 u»
Bis (2-ethylhexyl) phthalate
78
47
10 *
11
20
7
u*
11 V*
Foot 3-4
Fluorene
79
23
6
2
U
Phenanthrene
480
100
43
10
Fluoranthene
1,200
160
71
12
Butyl benzyl phthalate
64
4.9
2 U
2
U
Bis (2-ethylhexyl) phthalate
78
47
2
2
u
Foot 4-5
Fluorene
79
23
Phenanthrene
480
100
Fluoranthene
1,200
160
Butyl benzyl phthalate
64
4.9
Bis (2-ethylhexyl) phthalate
78
47
5
52
75
4 U
5
Note: Recovered core sections did not contain the entire 1 foot section in some cases. Figure 3-2 indicates recoveries for each sample.
U = Undetected
* Organic carbon content is less than 0.5% in this sample and should not be directly compared to organic carbon normalized criteria.
Indicates that the value exceeds SQS (Sediment Quality Standards).
Indicates that the value exceeds CSL (Cleanup Screening Levels).
Source: Parametrix, Inc., December 1996.
NOTE: Results presented in mg/kg organic carbon.
152679.PR.02_E062000009SEA. Table B-4 Organic Compound Concentrations Subsurface Sediments mgkg oc . 6-20-00 . gr
Table B-4
Organic Compound Concentrations
in Subsurface Sediments
(mg/kg organic carbon)
Asarco Sediments/Groundwater OU 06 ROD
-------
Chemical
AET
Dry Wt.
5-0
5.5-0
8-1
9-1
11-0
11-1
12.5-1
14-2
Foot 0-1
Fluorene
540
24
N/A
N/A
N/A
N/A
N/A
N/A
17 U
Phenanthrene
1500
290
N/A
N/A
N/A
N/A
N/A
N/A
17 U
Fluoranthene
1700
670
N/A
N/A
N/A
N/A
N/A
N/A
17 U
Butyl benzyl phthalate
63
19 U
N/A
N/A
N/A
N/A
N/A
N/A
17 U
Bis(2-ethylhexyl)phthalate
1300
100
N/A
N/A
N/A
N/A
N/A
N/A
17 U
Foot 1-2
Fluorene
540
18 U
N/A
N/A
N/A
N/A
N/A
17 U
Phenanthrene
1500
18 U
N/A
N/A
N/A
N/A
N/A
17 U
Fluoranthene
1700
18 U
N/A
N/A
N/A
N/A
N/A
17 U
Butyl benzyl phthalate
63
18 U
N/A
N/A
N/A
N/A
N/A
17 U
Bis (2-ethylhexyl) phthalate
1300
18 U
N/A
N/A
N/A
N/A
N/A
17 U
Foot 2-3
Fluorene
540
18 U
N/A
N/A
30
16 U
Phenanthrene
1500
54
N/A
N/A
310
16 U
Fluoranthene
1700
100
N/A
N/A
470
16 U
Butyl benzyl phthalate
63
18
N/A
N/A
17 U
16 U
Bis (2-ethylhexyl) phthalate
1300
38
N/A
N/A
17 U
16 U
Foot 3-4
Fluorene
540
N/A
N/A
Phenanthrene
1500
N/A
N/A
Fluoranthene
1700
N/A
N/A
Butyl benzyl phthalate
63
N/A
N/A
Bis (2-ethylhexyl) phthalate
1300
N/A
N/A
Foot 4-5
Fluorene
540
N/A
Phenanthrene
1500
N/A
Fluoranthene
1700
N/A
Butyl benzyl phthalate
63
N/A
Bis (2-ethylhexyl) phthalate
1300
N/A
Note: Recovered core sections did not contain the entire 1 foot section in some cases. Figure 3-2 indicates recoveries for each sample.
U = Undetected
N/A organic carbon content is greater than 0.5% in this sample. Value is normalized for TOC and reported in Table 3-3 .
Source: Parametrix, Inc., December 1996.
NOTE: Results presented in g/kg dry weight.
Table B-5
Organic Compound Concentrations
in Subsurface Sediments
(g/kg dry weight)
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-5 Organic Compound Concentrations Subsurface Sediments ugkg dry wt. 6-20-00 . gr
-------
Chemical
Metals (jig/L)
Arsenic +3
Arsenic +5
Total Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Nickel
Silver
Zinc
Mercury
Organics (ng/L)
LP AH
HPAH
C'onventionals
pH
Marine EPA Criteria
Chronic Acute
PW 5025
PW 505
PW 651
PW 91
PW 1020
36
69
9.3
43
50
1,100
2.9
2.9
,000 a
8.5
220
8
75
0.92
2.3
86
95
1.1
2.1
2,205
23
30
5 U
5 U
65
5 Ue
512 Ee
5 U
1,853
50 U
0.40
50 U
0.44
50 U
0.44
50 U
0.20 e
50 U
0.20 U
Ammonia (as nitrogen) (mg/L) 0.035 0.230
0.023
0.056
0.048
Sulfide (as hydrogen sulfide) (mg/ 0.002
1 10lu
1.0
U
1.0
PW 132
4.0 U
See notes on Table B-6 2 of 2.
18
5 U
25
3 U
10 U
SO
Ue
50
Ue
50
U
50
U
50
U
50
1
Ue
1
Ue
1
Ue
1
U
1
Ue
I
5 e
362 Ee
U
U
50 U
0.37 e
Acenaphthylene
--
3.0
U
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Acenaphthene
710 b
485 b,c
3.0
U
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Anthracene
3.0
U
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Fluorene
3.0
U
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Naphthalene
214 f
1175 b,c
3.0
U
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Phenanthrene
4.6
7.7
3.0
u
3.3 U
3.3
U
1 50 U
5.7 |U.
6.7|U
2-Methylnaphthalene
--
--
3.0
u
3.3 U
3.3
U
5.0 U
5.7 U
6.7 U
Total LPAHs
--
--
21.0
23.1
23.1
35.0
39.9
46.9
Benzo(a)anthracene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Benzo(a) pyrene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Benzo(b)fluoranthene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Benzo(k)fluoranthene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Total benzofluoranthenes
--
6.0
6.6
6.6
10.0
11.4
13.4
Benzo(g,h,i)perylene
--
6.1 U
6.6 U
6.5 U
10.0 U
11.0 U
13.0 U
Chrysene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Dibenzo(a,h)anthracene
--
6.1 U
6.6 U
6.5 U
10.0 U
11.0 U
13.0 U
Fluoranthene
16 b
20 b,c 3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Indeno( 1,2,3 ,-cd)pyrene
--
6.1 U
6.6 U
6.5 U
10.0 U
11.0 U
13.0 U
Pyrene
--
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Total HPAHs
39.3
42.9
42.6
65.0
72.9
85.9
Total PAHs
30 d 150 b,c | 60.31
| 66.01
1 65'7I
I 100.01
| 112.8 j
132.8!
Phthalates
Bis(2-ethylhexyl) phthalate
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Butyl benzyl phthalate
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Diethyl phthalate
5.9
4.1
3.3 U
5.0 U
5.7 U
6.7 U
Dimethylphthalate
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Di-n-butyl phthalate
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
Di-n-octyl phthalate
3.0 U
3.3 U
3.3 U
5.0 U
5.7 U
6.7 U
7.4
| 0.70011
4.5
Source: Parametrix, Inc., April 1996.
Table B-6 1 of 2
Pore Water Chemical Concentrations
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-6 1of2 Pore Water Chemical Concentrations . 6-20-00 . gr
-------
Chemical
Marine EPA Criteria
Chronic Acute PW 1435 PW1651
PW 1651
(Pup)
PW 172 PW 1851 PW 1852
PW
REF 2
Metals (pg/L)
Arsenic +3
Arsenic +5
Total Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Nickel
Silver
Zinc
Mercury
Organics (pg/L)
LPAH
19
5 U
36
9.3
50
2.9
1,000 i
8.5
0.92
86
i'.i
69
43
1,100
2.9
220
75
2.3
95
2.1
49
5 Ue
6,076 Ee
5 Ue
72'Ee
5 Ue
72 Ee
3<
wr
5 Ue
971 Ee
^ ^
0.33 e
0.44 e
0.44 e
1.00 e
5 Ue
185 Ee
6 e
1,428 Ee
5 U
692
0.29 e
0.64 e
0.20 U
HPAH
Benzo(a)anthracene
Benzo(a) pyrene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Total benzofluoranthenes
Benzo(g,h,i)perylene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Indeno( 1,2,3,-cd)pyrene
Pyrene
Total HPAHs
Total PAHs
Phthalates
16 b
30 d
Conventional
pH
Ammonia (as nitrogen) (mg/L) 0.035
Sulfide (as hydrogen sulfide) (mg/ 0.002
0.230
7.5
1.300H
ToTu
a Freshwater criteria.
b Insufficient data to develop criteria. Value presented is the L.O.E L.
c LC50 value divided by 2.
d Acute-to-chronic ratio of 10 used to develop criterion,
f Chemical specific acute-to-chronic ratio used to develop criterion.
PW
REF 6
13
11
44
10
21
5
17
5 U
5 U
5 U
5 U
5 U
5 U
5 U
3 t
ZZ3I 1
40
6
21
22 e
42|e
"Tu L
—Tu
3 U
3 U
3 U
3 Ue
3 Ue
10 Ue
10 u
10 u
10 u
10 U
10 U
10 Ue
l5|Ue
5 U
952
Ue
Ue
50
~f
50 U
0.20 U
Acenaphthylene
4.8
U
3.7 U
3.6 U
6.1
U
4.2
U
18.0 U
4.3 U
4.7 U
Acenaphthene
710 b
485 b,c
4.8
U
3.7 U
3.6 U
6.1
u
4.2
U
18.0 U
4.3 U
4.7 U
Anthracene
4.8
u
3.7 U
3.6 U
6.1
u
4.2
U
18.0 U
4.3 U
4.7 U
Fluorene
4.8
u
3,7 U
3.6 U
6.1
u
4.2
U
18.0 U
4.3 U
4.7 U
Naphthalene
214 f
1175 b,c
4.8
u
3,7 U
3.6 U
6.1
u
4.2
U,
18.0 U
4.3 U
4.7 U
Phenanthrene
4.6
7,7 [
4.8
1"
3.7 U
3.6 U
1 61
u
4.2
ul
1 i8.odu
4.3 U
1 4'7IU
2-Methylnaphthalene
--
--
4.8
u
3.7 U
3.6 U
6.1
u
4.2
U
18.0 U
4.3 U
4.7 U
Total LPAHs
33.6
25.9
25.2
42.7
29.4
126.0
30.1
32.9
-- •
4.8 U
3.7 U
3.6 U
6.1 U
4.2
U
18.0 u
4.3 U
4.7 U
--
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18.0 U
4.3 U
4.7 U
--
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18.0 U
4.3 U
4.7 U
--
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18.0 U
4.3 U
4.7 U
--
9.6
7.4
7.2
12.2
8.4
36.0
8.6
9.4
9.6 U
7.4 U
7.2 U
12 U
8.3
u
36,0 U
8.5 U
9.4 U
--
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18,0 U
4.3 U
4.7 U
--
9.6 U
7.4 U
7.2 U
12 U
8.3
u
36,0 U
8.5 U
9.4 U
20 b,c
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18.0|U
4.3 U
4.7 U
--
9.6 U
7.4 U
7.2 U
12 U
8.3
u
36.0 U
8.5 U
9.4 U
4.8 U
3.7 U
3.6 U
6.1 U
4.2
u
18.0 U
4.3 U
4.7 U
62.4
48.1
46.8
78.7
54.3
234.0
55.6
61.1
150 b,c[~
96.01
74.0|
72.0
[ 121.4
83.7]
I 360.0|
85.71
94.0
Bis(2-ethylhexyl) phthalate
4.8
i U
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4.7 U
Butyl benzyl phthalate
4.8
; u
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4 7 U
Diethyl phthalate
4.8
1 u
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4.7 U
Dimethylphthalate
4.8
1 u
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4.7 U
Di-n-butyl phthalate
4.8
: u
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4.7 U
Di-n-octyl phthalate
4.8
i u
3.7 U
3.6 U
6.1 U
4.2
U
18.0 U
4.3 U
4.7 U
E - Estimated.
U = Undetected at the reported detection limit,
e = Estimated.
- - = No data available.
| | Value exceeds chronic marine EPA criteria.
1 Value exceeds acute and chronic marine EPA criteria.
Source: Parametrix, Inc., April 1996.
Table B-6 2 of 2
Pore Water Chemical Concentrations
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-6 2of2 Pore Water Chemical Concentrations . 6-20-00 . gr
-------
Echinoderm Neanthes
Ampelisca Combined Station Mean Total
Sample Mortality Normality/Survivorship Biomass
Station (%)* (%)** (mg)§
Carr 2
13
89.6
97.35
Carr4
19
83.9
137.30
REF 3
45 §§
39.0 #
96.63 §
REF4B
31 §§
55.8#
89.36
2-2
26
73.3
67.85
2-3
43.
81.4
74.36
2-4
30
44.9
*.b
87.59
46
41.2
a
53.90
C
3-2
31
70.8
84.40
3-3
32
52.5
91.54
4-2
88
a
61.5
46.72
4-3
29
43.9
a,b
82.46
5-0
24
71.3
137.18
5-0.25
94
a
24.2
0.00
b
5-0.5
92
a
31.2
«,b
0.00
b
5-1
48
61.0
109.55
5-2
33
61.3
114.82
5-3
32
73.2
116.14
5.5-0
24
74.8
145.38
6-2
77
a
36.2
a,b
81.68
6.5-0
72
a,b
69.0
98.78
6.5-1
73
a,b
3.1
a,b
0.00
b
6.5-2
60
32.1
a,b
82.39
6.5-3
63
81.8
137.34
7-3
33
50.0
90.01
7-4.5
37
82.8
128.87
7-12
47
38.8
a,b
84.55
8-1.5
86
a
0.1
a
0.00
b
8-2.5
71
a,b
44.3
a.b
50.48
8-3.5
24
87.8
109.64
9-1***
100
a
8.5
42.29
9-2
33
60.0
83.69
9-2.5
43
63.8
105.49
10-1.5
47
43.5
a,b
84.60
10-2
40
48.8
a,b
92.48
10-2.5
37
50.9
91.58
11-0
99
B
| 0.2
¦.b
0.00
r
11-2
17
58.7
46.06
11-2.5
34
73.8
98.97
12-2
27
83.0
109.66
See notes on Table B-7 2 of 2.
Source: Parametrix, inc., April 1996.
Table B-7 1 of 2
Sediment Bioassay Results
(Replicate Means) and Comparison
to State Bioassay Criteria
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-7 1of2 Sediment Bioassay Results Replicate Means Comparison to State Bioassay Criteria . 6-20-00 . gr
-------
Station
Ampelisca
Sample Mortality
(%)*
Echinoderm
Combined Station
Normality/Survivorship
(%)**
Neanthes
Mean Total
Biomass
(mg)§
12-2.5
52
13-2
35
13-2.5
49
14-1
99
14-2
81
14-2.5
45
14-3.5
55
15-1
98
15-2
42
15-2.5
23
15.5-1
82
15.5-2
63
16-0.5
21
16-1
22
16-2
36
16.5-1***
29
16.5-2
32
17-1
54
17-1.5
20
17-2
24
17.5-1***
24
17.5-2
26
18-2.5
39
18-3.5
27
18.5-1
47
18.5-2
26
49.1
73.9
54.3
94.65
98.18
98.74
0.1
a,b
8.24
75.2
78.6
54.0
78.52
108.52
56.75
0.0
37.22
67.9
71.7
57.6
53.1
48.6
52.4
86.56
89.71
62.62
87.06
63.99
97.83
94.65
94.12
100.75
79.53
78.85
93.13
68.84
79.48
87.21
90.38
85.89
91.63
* State SQS criteria for amphipod bioassays: sediment fails if mortality is > 25% and significantly greater than reference.
* * State SQS criteria for echinoderm larval bioassay: sediment fails if normal survivorship is < 85% of and significantly lower than reference.
*** Stations with greater than 20% fines that are compared to reference station Carr4.
§ State SQS criteria for polychaete bioassay: sediment fails if mean biomass < 70% of and significantly lower than reference.
§§ Does not meet reference station requirements defined by state criteria.
* Does not meet reference station requirements defined by PSDDA.
Boxed values indicate the result exceeds state SQS and CSL criteria.
"Not significantly different from REF 3.
bNot significantly different from REF 4B.
c Not significantly different from Carr 2.
d Not significantly different from Carr 4.
Source: Parametrix, Inc., April 1996.
Table B-7 2 of 2
Sediment Bioassay Results
(Replicate Means) and Comparison
to State Bioassay Criteria
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-7 2of2 Sediment Bioassay Results Replicate Means Comparison to State Bioassay Criteria . 6-20-00 . gr
-------
Station
Year
Bioassay3
Benthic lnfaunab
Amphipod
Bivalve
Echinoderm
Polychaeta
Mollusca
Crustacea
1-1
1988
6
80
-
--
-
--
2-1
1988
4
87*
~
--
'--
--
2-5**
1988
19
60
--
0.20*
0.10*
0.14*
3-2
1988
11
50
-
--
-
-
3-3
1989
16
-
24
0.55
0.11*
0.44
3-4**
1988
14
76
--
--
"
--
1989
18
--
49*
0-71
0.14*
0.44
3-5"
1988
31*
80
-
0.41
0.18*
0.46
3-6
1988
3
54
-
--
-
-
4-0**
1990
14
-
72*
3.09
0.54
0.58
4-1**
1989
95*
--
27
2.26
0.78
0.74
4-2**
1988
49*
74
-
2.58
0.96
1.91
4-3"
1989
32
--
54*
1.80
0.23
1.56
5-0"
1988
9
86793*
-
--
--
-
1990
14
¦ -
56*
0.91
0.18*
0.06*
5-2**
1990
18
-
57*
0.62
0.21*
1.72
5-3
1989
20
--
16
0.38
0.13*
0.45
5-4**
1989
24
--
50*
-
--
-
5.5-2"
1990
32
--
85*
0.81
0.27*
1.29
6-0
1990
17
-
58
3.69
0.04*
0.37
6-1"
1988
97*
-
--
-
--
-
1990
43
-
41
0.96
0.29*
1.00
6-2**
1989
23
-
30*
-
-
"
1990
26
-
55*
0.85
0.28*
1.27
6-3
1988
22
69
--
0.95
0.72
1.65
1990
16
--
45
0.75
0.33*
2.31
6-4
1989
12
--
10
0.28
0.12*
0.23
6.5-2"
1990
38
-
100*
0.88
0.22
1.34
7-2**
1990
48
--
89*
0.76
0.36
0.40
8-2
1989
13
--
38*
0.33
0.24
0.53
See notes on Table B-8 2 of 2.
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-8 1 of 2
Summary of Biological Data
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-8 1of2 Summary Biological Data . 6-21-00 . gr
-------
Station
Year
Bioassay®
Benthic lnfaunab
Amphipod
Bivalve
Echinoderm
Polychaeta
Mollusca
Crustacea
8-3**
1989
17
--
44*
0.61
0.41
1.42
8-4
1988
17
70
--
0.86
0.65
1.73
10-1"
1988
14
997,100*
-
1.46
0.20*
1.54
10-2**
1988
7
97791*
-
-
--
--
1989
14
-
45*
1.39
0.54
1.80
10-3
1989
20
-
22
0.58
0.42
1.11
11-7**
1988
4
70/57
--
0.07*
0.03*
0.09*
12-1"
1988
62*
99793*
-
4.88
0.04*
0.43
12-2"
1989
16
-
45*
1.31
0.23
0.57
12-3
1389
11
--
40*
0.77
0.43
0.83
14-1**
1989
74*
--
99*
0.23
0.20*
0.14*
14-2
1989
7
--
21
0.47
0.55
0.39
14-3"
1989
15
--
63*
0.94
0.39
1.41
16-1
1988
5
86789*
--
0.60
0.23
1.34
16-2
1989
19
-
32*
0.38
0.26
0.58
16-3
1989
15
33*
0.47
0.23
0.55
16-4"
1988
17
98792*
-
0.36
0.20*
0.21*
18-1"
1989
19
--
40*
0.76
0.22*
2.59
18-2"
1988
14
98799*
-
--
--
-
1989
12
--
48*
1.40
0.29
1.38
18-3**
1989
37*
--
2
-
-
-
19-1
1989
8
--
22
0.86
0.58
2.40
19-2
1989
24
-
2
0.85
0.23*
1.33
"Bioassay results in absolute mortality (amphipod) and combined abnormality/mortality (bivalve and echinoderm). For bivalves, assays were
performed twice in 1988 at certain sample locations. Data from both sets of analyses are presented; the greater response was used to
characterize the sample station.
'Benthic infauna is ratio of station to reference (i.e., indicated value = station abundance •+¦ reference abundance).
* Exceeds problem area biological threshold value.
" Station identified as cleanup station based on at least one exceedance of MCUL biological criteria.
- Data not collected during indicated sampling event
Source: Supplemental Feasibility Study, Commencement Bay NearshorelTideflats,
Asarco Sediments Site, October 1993.
Table B-8 2 of 2
Summary of Biological Data
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-8 2of2 Summary Biological Data . 6-21-00 . gr
-------
Station
Polychaetes
Molluscs
Crustaceans
Miscellaneous
REF2
REF3
REF4B
365
491
235
144
92
64
128
57
23
40
267
20
2-2*
373
57
93
122
2-3*
235
39
81
70
2-4*
164
35
44
36
3-1
452
31
47
58
3-2
255
53
51
245
3-3*
423
43
79
86
4-2*
598
49
60
325
4-3*
382
46
92
556
5-0
519
134
19 b
12
a
5-1
574
94
124
125
5-2*
313
48
115
95
5-3*
139
24
37
28
5.5-0
1,586
191
83
13
a
6-2
465
68
98
165
6.5-0
539
31
46 b
3
a
6.5-2
321
40 b
37 b
63
6.5-3
146 a
30
33 b
30
a
7-12*
139
22
40
16
7-3
200 a
46
73
70
7-4.5
152 a
45 b
41 b
35
a
8-1.5
432
43 b
49 b
36
a
8-2.5
311
52
102
87
8-3.5
194 a
37
62
40
a
9-1
73
7
43
0
9-2
156 a
52 b
40 b
60 a
9-2.5
338
54
86
82
10-1.5
369
78
58
45 a
10-2
332
78
51 b
59 a
10-2.5
335
79
107
151
11-0
1
l|
3
0
11-2
248
88
63
90
11-2.5
208
46 b
58
93
12-2
510
272
79
33 a
12-2.5
362
173
61
48 a
13-2
495
211
80
37 a
13-2.5
594
230
96
86
14-1
102
31
68
4 a
14-2
67
11
24 b
10 a
14-2.5
203
102
66
50 a
14-3.5
274
84
54
424
15-1
28
15
11 b
3 a
15-2
196 a
32
62 b
48 a
15-2.5
1241
54
41 b
28
a
See notes on Table B-9 2 of 2.
Source: Parametrix, Inc., April 1996.
Table B-9 1 of 2
Replicate Mean Abundances of Major
Taxa Compared to Reference Stations
Using Kruskal-Wallis Tests
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-9 1of2 Replicate Mean Abundances Major Taxa Compared to Ref Stations Using KW Tests . 6-21-00 . gr
-------
Station
Polychaetes
Molluscs
Crustaceans
Miscellaneous
15.5-1
15.5-2
16-0.5
16-1
16-2
16.5-1
16.5-2
17-1
17-1.5
17-2
17.5-1
17.5-2
18-2.5
18-3.5
18.5-1
18.5-2
288
361
658
183 a
96
393
394
667
356
289
1,183
293
259
313
154 a
307
59
53 b
16 a
97
137
55 a
127
138
47 a
33
59 b
40 a
25
19 b
45 a
91
352
29
78
200
77
52 b
829
62 a
48 b
80
32 a
31
114
67 a
111
185
50
46
201
76
44 b
142
102
63
91
36 a
19
69
9 a
40 b
201
82
Boxed values indicate mean replicate abundance that is significantly less than all appropriate
reference stations.
* These stations had depths greater than 150 feet and were compared to REF4B only,
a Replicate abundance significantly less than REF3 and depth less than 150 feet,
b Replicate abundance significantly less than REF2 and depth less than 150 feet.
Source: Parametrix, Inc., April 1996.
Table B-9 2 of 2
Replicate Mean Abundances of Major
Taxa Compared to Reference Stations
Using Kruskal-Wallis Tests
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-9 2of2 Replicate Mean Abundances Major Taxa Compared to Ref Stations Using KW Tests . 6-21-00 . gr
-------
Chemical
REF
IB
IB Dup.
2A
2B
3A
3B
Metals (mg/kg)
Arsenic +3
0.002 U
0.002 U
0.002 U
0.007
0.002 U
0.002 U
0.003
Arsenic +5
0.017
0.034
0.180
0.39
0.081
0.021
0.030
Monomethyl Arsenic
0.005
0.002
0.007
0.011
0.002
0.002
0.003
Dimethyl Arsenic
1.5
4.5
5.3
7.7
7.0
2.2
3.3
Total Arsenic
0.40
0.85
10
1.9
1.7
0.92
0.75
Cadmium
0.02
0.01
0.02
0.02
0.02
0.02
0.02
Chromium
0.039
0.16
0.049
0.066
0.077
0.067
0.058
Copper
4.7
0.72
6.3
5.6
6.5
5.5
5.0
Mercury
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
Nickel
0.16
0.035
0.14
0.18
0.042
0.037
0.63
Lead
0.56
1.3
3.8
2.0
1.5
1.2
0.75
Silver
0.016
0.015
0.092
0.017
U
0.018
U
0.015
0.016
Zinc
14
12
24
14
16
14
14
Orgaiiics (jig/kg)
LP AH
Acenaphthylene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Acenaphthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Fluorene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Naphthalene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Phenanthrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
2-Methylnaphthalene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Total LPAHs
231
231
231
231
224
224
224
HP AH
Benzo(a)anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(a) pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(b)fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(k)fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(g,h,i)perylene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Chrysene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Dibenzo(a,h)anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Indeno( 1,2,3,-cd)pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Total HPAHs
330
330
330
330
320
320
320
Total PAHs
561
561
561
561
544
544
544
Phthalates
Bis(2-ethylhexyl) phthalate
97
| 510
1
33 U
41
120
32 U
100
Butyl benzyl phthalate
33 U
33 U
| 170
u
33 U
160
U
32 U
69
Diethyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Dimethyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Di-n-butyl phthalate
44
33 U
33 U
33 U
32 U
32 U
32 U
Di-n-octyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Conventionals
Moisture (%)
78
77
76
79
78
80
76
Lipids (%)
5.3
15
9.0
5.5
5.8
6.0
6.2
U = Undetected at reported detection limit.
j ] Boxed values are greater than Reference values for that station.
Source: Parametrix, Inc., April 1996.
Table B-10
Rock Sole Whole Body Tissue
Chemical Concentrations
(wet weight)
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-10 Rock Sole Whole Body Tissue Chemical Concentrations wet wt. 6-21 -00 . gr
-------
Chemical
REF
IB
IB Dup.
2A
2B
3A
3B
Metals (mg/kg)
Arsenic +3
0.002 U
0.002 U
0.002 U
0.007
0.002 U
0.002 U
0.003
Arsenic +5
0.017
0.034
0.180
0.39
0.081
0.021
0.030
Monomethyl Arsenic
0.005
0.002
0.007
0.011
0.002
0.002
0.003
Dimethyl Arsenic
1.5
4.5
5.3
7.7
7.0
2.2
3.3
Total Arsenic
0.40
0.85
10
1.9
1.7
0.92
0.75
Cadmium
0.02
0.01
0.02
0.02
0.02
0.02
0.02
Chromium
0.039
0.16
0.049
0.066
0.077
0.067
0.058
Copper
4.7
0.72
6.3
5.6
6.5
5.5
5.0
Mercury
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
0.02 U
Nickel
0.16
0.035
0.14
0.18
0.042
0.037
0.63
Lead
0.56
1.3
3.8
2.0
1.5
1.2
0.75
Silver
0.016
0.015
0.092
0.017
U
0.018
U
0.015
0.016
Zinc
14
12
24
14
16
14
14
Orgaiiics (jig/kg)
LP AH
Acenaphthylene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Acenaphthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Fluorene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Naphthalene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Phenanthrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
2-Methylnaphthalene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Total LPAHs
231
231
231
231
224
224
224
HP AH
Benzo(a)anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(a) pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(b)fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(k)fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Benzo(g,h,i)perylene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Chrysene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Dibenzo(a,h)anthracene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Fluoranthene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Indeno( 1,2,3,-cd)pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Pyrene
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Total HPAHs
330
330
330
330
320
320
320
Total PAHs
561
561
561
561
544
544
544
Phthalates
Bis(2-ethylhexyl) phthalate
97
| 510
1
33 U
41
120
32 U
100
Butyl benzyl phthalate
33 U
33 U
| 170
u
33 U
160
U
32 U
69
Diethyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Dimethyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Di-n-butyl phthalate
44
33 U
33 U
33 U
32 U
32 U
32 U
Di-n-octyl phthalate
33 U
33 U
33 U
33 U
32 U
32 U
32 U
Conventionals
Moisture (%)
78
77
76
79
78
80
76
Lipids (%)
5.3
15
9.0
5.5
5.8
6.0
6.2
U = Undetected at reported detection limit.
j ] Boxed values are greater than Reference values for that station.
Source: Parametrix, Inc., April 1996.
Table B-11
Rock Sole Fillet Tissue
Chemical Concentrations
(wet weight)
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02_E062000009SEA. Table B-11 Rock Sole Fillet Tissue Chemical Concentrations wet wt. 6-21 -00 . gr
-------
Chemical
*3
*E
S3
<5
X
£
J
<
Q
A
I
<
I
SO
3
c
-------
§
3
s
tn
§¦
-g
§¦
8-
§•
¦e
&
§¦
is
0
1
CJ
If
'3
£3
<25
Si
£5
to
Chemical ig
a
<
s
<
fS
03
r>i
<
r"*i
<
Metals (rag/kg)
Arsenic +3
0,002 U i
0.006 |U
--
0.002
0.002 U
0.002 u
0.002 U
Arsenic +5
0,013
0.012 U
• •
0.077
0.019
0.018
0.010
--
Total Arsenic
0.25
0.37
0.33
0.71
0.2S
0.42
0.23
0.84
Cadmium
0.04
0.08
0.06
0.13
0.07
0.01
U
0.01 U 0.13
Chromium
0.05
0.10
0.05
0,05
0.13
0.03
1
0.111
0.02
Copper
0.4
0.4
0.3
0,7
0.2
0.2
0.3
41.0
Mercury
0.02 U
Q.02 U
0.02 U
0.02 U
0.02 V
0.02 U
0.02 U 0.02 U
Nickel
0.05
0.18
0.03
0.03
0.03
0.05
0.04
0.19
Lead
0,04
0.05 i
0,16
1
0.68
0.10
1
0.09
0.111
0.89
Silver
0.02 U
0.02 U
0.01
0.01
0.01
0.01
0.02
0.32
Zinc
2.7
3.8!
1
4.0
2.0
3.4
1.9
16.0
Organic* Oig/k£)
LP AH
Acenaphthyiene
31 U
32
U
33
U
33
u
33
U
33
u
33
u
Asenaphthene
31 U
32
O
33
U
33
u
33
u
33
u
33
u
Anthracene
31 U
32
u
33
0
33
u
33
u
33
u
33
u
Fluorenc
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Naphthalene
31 U
32
u
33
u
33
0
33
u
33
u
33
u
Phenanthreae
31 U
32
u
33
u
33
V
33
u
33
u
33
u
2-Methylnaphthalene
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Total LPAHs
217
224
231
231
231
231
231
--
HP AH
Ben20(a)«ithracsne
31 U
32
u
33
u
33
u
33
V
33
u
33
u
Benzo(a) pyrene
31 U
32
u
33
u
33
u
33
u
33
V
33
u
Benzo(b)fluorwithene
31 U
32
u
33
u
33
0
33
u
33
u
33
u
B«nzo(k)lIuor»itthene
31 U
32
u
33
u
33
0
33
u
33
u
33
u
Bonzo(g.h.i)peryiene
31 U
32
u
33
u
33
0
33
0
33
u
33
u
Chryjene
31 V
32
u
33
u
33
u
33
0
33
u
33
u
Dibemo{%h)antliracMie
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Fhioianthene
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Indeno< l,2,3,-cd)pyrenc
31 U
32
u
33
0
33
u
33
u
33
u
33
u
Pyrene
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Total HPAHs
310
320
330
330
330
330
330
--
Total PAHs
52?
544
*1|
561
561
561|
XI
--
Phthalstes
Bii(2-cthy[hcxyl} phthalMe
31 U
32
u
33
u
33
V
33
V
33
u
33
u
Butyl benzylphthalate
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Diethyl phthalate
31 U
32
u
33
u
33
V
33
u
33
u
33
u
Dimethyl phthalate
31 U
32
u
33
u
33
V
33
u
33
u
33
tf
Di-n-butvl phOialatt
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Di-n-octyi phthaiatc
31 U
32
u
33
u
33
u
33
u
33
u
33
u
Conventtonab
Moisture (%)
94
94
94
93
88
93
95
79
Lipids {%)
2.2
0,97
1.2
0.1 U
0,1
u
2.0
2.7
1.1
Source: Parametrix, Inc., April 1996.
Table B-12 2 of 2
Benthic Invertebrate Tissue Chemical
Concentration (Wet Weight)
Asarco Sediments/Groundwater OU 06 ROD
152679.PR.02 E062000009SEA. Table B-12 2of2 Benthic Invertebrate Tissue Chem Concen . 7-6-00 . gr/jg
-------
This page is intentionally blank.
-------
APPENDIX C
Outcome of Preponderance of Evidence
Approach for Marine Sediments
-------
This page is intentionally blank.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
1-1a
N
N
N/A
N/A
N/A
N/A
N/A
1
No identified exceedances of SQS chemical criteria;
bioassay data suggest no current impacts based on lack of
significant differences from reference responses.
2-1 a
[Y]
N
L
N/A
N/A
N/A
N/A
N/A
4
Sediment concentrations of As and Hg exceed CSL criteria
and minimal adverse biological effects indicated by one
bioassay response (bivalve larval effective mortality)
significantly higher than reference.
2-2
[Y]
N
N
N
2
Sediment concentration of As exceeded CSL criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
2-3
N
N
N
N
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
2-4
N
N
[L]
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by one bioassay
response (echinoderm larval effective mortality) significantly
higher than reference.
2-5a
N
N
[C,M,P]
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by benthic
infaunal abundances of three major taxonomic groups
significantly depressed relative to reference.
2-6a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
3-1
[Y]
N
[UP]
[C,M]
Y
Y
5
Multiple exceedances of CSL criteria for sediment chemicals
(As, Cu, Pb, Zn) and bioassay and benthic responses
significantly different from reference, combined with
dominance of pollution-tolerant taxa, suggestive of moderate
to severe impacts.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
3-2
[Y]
N
N
N
2
Sediment concentrations of As and Zn exceeded CSL
criteria but current biological impacts not suggested given
lack of significant differences from reference in bioassay
responses and benthic community structure.
3-3
[Y]
N
N
N
2
Sediment concentrations of As, Pb and Zn exceeded CSL
criteria but current biological impacts not suggested given
lack of significant differences from reference in bioassay
responses and benthic community structure.
3-4a
[Y]
N
[L]
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference and mollusc abundance significantly lower than
reference.
3-5a
[Y]
N
A
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
amphipod mortality significantly higher than reference and
mollusc abundance significantly lower than reference.
3-6a
[Y]
N
N/A
N/A
N/A
N/A
N/A
2
Sediment concentrations of As, Cu, Pb and Zn exceeded
CSL criteria but current biological impacts not suggested
given lack of significant differences from reference in
bioassay responses.
4-0a
[Y]
[Y]
[L]
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, Zn, and individual
PAHs exceed CSL criteria and minimal adverse biological
effects indicated by echinoderm larval effective mortality
significantly higher than reference.
4-1 a
[Y]
N
[A]
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
amphipod mortality significantly higher than reference.
4-2
[Y]
N
[A]
J
Y
N
4
Sediment concentrations of As, Cd, Cu, Pb, Ag, and Zn
exceed CSL criteria and minimal adverse biological effects
indicated by amphipod mortality significantly higher than
reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
4-3
[Y]
N
[L]
H,J,S,SDI
N
N
4
Sediment concentrations of As, Cd, Cu, Pb and Zn exceed
CSL criteria and minimal adverse biological effects indicated
by echinoderm larval effective mortality significantly higher
than reference and diversity indices lower than reference.
4-4a
N
[Y]
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of a phthalate
ester in exceedance of the CSL criterion.
5-0
[Y]
Y
H,J,S,SDI
Y
Y
5
Dominance of the benthic community by pollution-tolerant
polychaetes indicative of moderate to severe benthic
impacts.
5-0.25
[Y]
N
[A, L, P]
N/A
N/A
N/A
N/A
N/A
5
In the absence of benthic data, the multiple CSL chemical
exceedances (As, Cd, Cr, Cu, Pb, Ag, and Zn), combined
with multiple bioassay responses significantly different from
reference, considered sufficient evidence of moderate to
severe impacts.
5-0.5
[Y]
N
[A, L, P]
N/A
N/A
N/A
N/A
N/A
5
In the absence of benthic data, the multiple CSL chemical
exceedances (As, Cr, Cu, Pb, Ag, and Zn), combined with
multiple bioassay responses significantly different from
reference, considered sufficient evidence of moderate to
severe impacts.
5-1
[Y]
N
N
N
2
Sediment concentrations of As, Cd, Cu, Pb, Ag, and Zn
exceeded CSL criteria but current biological impacts not
suggested given lack of significant differences from
reference in bioassay responses and benthic community
structure.
5-2
[Y]
N
N
N
2
Sediment concentrations of As, Cd, Cu, Pb, Ag, and Zn
exceeded CSL criteria but current biological impacts not
suggested given lack of significant differences from
reference in bioassay responses and benthic community
structure.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
5-3
[Y]
N
N
N
2
Sediment concentrations of As, Cu, Pb, and Zn exceeded
CSL criteria but current biological impacts not suggested
given lack of significant differences from reference in
bioassay responses and benthic community structure.
5-4a
[Y]
N/A
[L]
N/A
N/A
N/A
N/A
N/A
4
Sediment concentration of As exceeded CSL criterion and
minimal adverse biological effects indicated by one bioassay
response (echinoderm larval effective mortality) significantly
higher than reference.
5.5-0
[Y]
N
C
H,J,S,SDI
Y
Y
5
Dominance of the benthic community by pollution-tolerant
polychaetes indicative of moderate to severe benthic
impacts.
5.5-2a
[Y]
N/A
[L]
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference and mollusc abundance significantly lower than
reference.
6-0a
[Y]
N
M
N/A
N/A
N/A
Y
5
Dominance of the benthic community by pollution-tolerant
polychaetes indicative of benthic impacts.
6-1 a
[Y]
N
[A]
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
amphipod mortality significantly higher than reference and
mollusc abundance significantly lower than reference.
6-2
[Y]
N
[A,L]
N
N
4
Sediment concentrations of As, Cd, Cu, Pb, Ag, and Zn
exceed CSL criteria and minimal adverse biological effects
indicated by amphipod mortality and echinoderm larval
effective mortality significantly higher than reference.
6-3a
[Y]
N
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
significantly depressed mollusc abundance relative to
reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
6-4a
Y
N
M
N/A
N/A
N/A
N/A
4
Sediment concentration of As only exceeded SQS criterion
but minimal adverse biological effects suggested by
significantly depressed mollusc abundance relative to
reference.
6.5-0
[Y]
N
[A]
M
TR
H,J,S,SDI
Y
Y
5
Multiple biological results, including bioassay and benthic
endpoints that were significantly different from reference and
dominance by pollution-tolerant species, suggestive of
moderate to severe impacts.
6.5-1
[Y]
N
[A, L, P]
N/A
N/A
N/A
N/A
N/A
5
In the absence of benthic data, the multiple CSL chemical
exceedances (As, Cd, Cr, Cu, Pb, Ag, and Zn), combined
with multiple bioassay responses significantly different from
reference, considered sufficient evidence of moderate to
severe impacts.
6.5-2
[Y]
N/A
[L]
N
N
4
Sediment concentrations of As, Cd, Cu, Pb, Ag, and Zn
exceed CSL criteria and minimal adverse biological effects
indicated by echinoderm larval effective mortality
significantly higher than reference.
6.5-3
[Y]
N
M
TA,DA
N
N
4
Sediment concentration of As exceeded CSL criterion and
minimal adverse biological effects indicated by mollusc
abundance and overall community abundance and dominant
taxa abundance significantly lower than reference.
7-1 a
[Y]
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As, Cu, Pb,
and Zn in excess of CSL criteria.
7-2a
[Y]
N
[L]
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference.
7-3
[Y]
N
N
N
2
Sediment concentrations of As and Cd exceeded CSL
criteria but current biological impacts not suggested given
lack of significant differences from reference in bioassay
responses and benthic community structure.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
7-4a
[Y]
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As in excess
of CSL criterion.
7-4.5
N
N
TA,DA
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by benthic
infaunal total abundance and dominant taxa abundance
significantly depressed relative to reference.
7-5a
Y
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As in excess
of SQS criterion.
7-6a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
7-7a
N
Y
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of a phthalate
ester in excess of SQS criterion.
7-12
N
N
[L]
M
Y
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
effective mortality significantly higher than reference and
mollusc abundance significantly depressed relative to
reference.
8-1 a
[Y]
[Y]
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As, Pb, Zn,
and a phthalate ester in excess of CSL criteria.
8-1.5
[Y]
N
[A, L, P]
H
Y
Y
5
Multiple biological results, including bioassay and benthic
endpoints that were significantly different from reference and
dominance by pollution-tolerant species, suggestive of
moderate to severe impacts.
8-2a
[Y]
N
L
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Hg, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
8-2.5
[Y]
N
[A,L]
N
N
4
Sediment concentrations of As and Hg exceed CSL and
SQS criteria, respectively, and minimal adverse biological
effects indicated by amphipod mortality and echinoderm
larval effective mortality significantly higher than reference.
8-3a
[Y]
N
[L]
N/A
N/A
N/A
N/A
4
Sediment concentrations of As exceeded CSL criterion and
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
8-3.5
Y
N
M
N
N
4
Sediment concentration of As only exceeded SQS criterion
but minimal adverse biological effects suggested by
significantly depressed mollusc abundance relative to
reference.
8-4a
Y
N
N/A
N/A
N/A
N/A
2
Sediment concentrations of As exceeded SQS criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic abundance data.
9-1
[Y]
N
[A, L, P]
[C,M,P]
TA,DA,TR,DR
H,J,S,SDI
Y
Y
5
Multiple indicators of biological impacts, including
significantly reduced abundance and richness values,
diversity values less than reference, and bioassay responses
significantly different from reference.
9-2
[Y]
N
N
N
2
Sediment concentrations of As exceeded CSL criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
9-2.5
Y
N
N
N
2
Sediment concentrations of As exceeded SQS criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
9-3a
Y
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As in excess
of CSL criteria.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
9-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
9-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
9-6a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
9-7a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
9-8a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
10-Oa
[Y]
[Y]
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As, Cu, Pb,
Zn, and individual PAHs in excess of CSL criteria.
10-1 a
[Y]
[Y]
[L]
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, and Zn exceed CSL
criteria and minimal adverse biological effects indicated by
bivalve larval effective mortality significantly higher than
reference.
10-1.5
[Y]
N
[L]
N
N
4
Sediment concentrations of As and Cu exceed CSL criteria
and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference.
10-2
Y
N
[L]
N
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
10-2.5
N
N
N
N
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
10-3a
Y
N
N/A
N/A
N/A
N/A
2
Sediment concentrations of As exceeded SQS criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic abundances.
10-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
11-0
[Y]
Y
[A, L, P]
[C,M,P]
TA,DA,TR
H,SDI
Y
Y
5
Multiple indicators of moderate to severe biological impacts,
including significantly reduced abundance and richness
values, diversity values less than reference, and bioassay
responses significantly different from reference.
11 -1 a
[Y]
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As, Cu, Pb,
and Zn in excess of CSL criteria.
11-2
N
N
N
N
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
11-2.5
[Y]
N
N
N
2
Sediment concentrations of Cu exceeded CSL criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic abundances.
11-3a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
11-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
11-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
11-6a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
11-7a
N
N
[C,M,P]
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by major benthic
taxonomic group abundances significantly depressed
relative to reference.
11-8a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
11-9a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
12-1 a
[Y]
[Y]
[A,L]
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As, Cu, Pb, Hg, and Zn exceed
CSL criteria and minimal adverse biological effects indicated
by bioassay mortality responses significantly higher than
reference and mollusc abundance significantly lower than
reference.
12-2
Y
N
TR,DR
H,J,SDI
N
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by richness and
diversity values lower than reference.
12-2.5
Y
N
H, SDI
N
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by diversity
values lower than reference.
12-3a
Y
N
L
N/A
N/A
N/A
N/A
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
12-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
12-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
13-1 a
[Y]
[Y]
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As, Cu, Pb,
Zn, and an individual PAH in excess CSL criteria.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
13-2
N
N
J
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by a diversity
value less than reference.
13-2.5
N
N
N
N
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
13-3a
Y
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As in excess
of the SQS criterion.
13-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
13-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
13-6a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
13-7a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
13-8a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
14-1
[Y]
N
[A, L, P]
[M,P]
TA,DA,TR
H,SDI
Y
Y
5
Multiple indicators of moderate to severe biological impacts,
including significantly reduced abundance and richness
values, diversity values less than reference, and bioassay
responses significantly different from reference.
14-2
[Y]
N
[A]
[M,P]
TA,DA,TR
H
Y
Y
5
Multiple indicators of moderate to severe biological impacts,
including significantly reduced abundance and richness
values, diversity values less than reference, and bioassay
responses significantly different from reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
14-2.5
Y
N
N
N
2
Sediment concentrations of As exceeded SQS criterion but
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic abundances.
14-3a
N
N
[L]
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effectively mortality response higher than reference.
14-3.5
N
N
J
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by a diversity
value less than reference.
14-4a
Y
N
N/A
N/A
N/A
N/A
N/A
N/A
2
Biological data not available, but minimal impacts considered
possible based on sediment concentrations of As in excess
of the SQS criterion.
14-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
15-1
[Y]
N
[A, L, P]
[M,P]
TA,DA,TR
H,SDI
Y
Y
5
Multiple indicators of moderate to severe biological impacts,
including significantly reduced abundance and richness
values, diversity values less than reference, and bioassay
responses significantly different from reference.
15-2
[Y]
N
M
N
N
4
Sediment concentrations of As exceeded CSL criterion and
minimal adverse biological effects indicated by mollusc
abundance significantly depressed relative to reference.
15-2.5
N
N
P
TA,DA
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by overall
abundance and polychaete abundance significantly
depressed relative to reference.
15-3a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
15-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
15-5a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
15.5-1
[Y]
N
[A]
H,J,S,SDI
Y
Y
5
Differences in benthic community structure, combined with
diversity measures lower than reference, considered
sufficient evidence of moderate to severe impacts.
15.5-2
[Y]
N
[L]
Y
N
4
Sediment concentrations of As and Cu exceeded CSL
criterion and minimal adverse biological effects indicated by
echinoderm larval effective mortality significantly higher than
reference.
16-0.5
[Y]
N
TR,DR
J
N
N
4
Sediment concentrations of As and CU exceeded CSL
criteria and minimal adverse biological effects indicated by
richness values significantly depressed relative to reference
and diversity indices lower than reference.
16-1
Y
N
[L]
M
N
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference
and mollusc abundance significantly depressed relative to
reference.
16-2
N
N
[L]
[M,P]
TA,DA
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by benthic
abundance values significantly depressed relative to
reference and bioassay exceedances of reference.
16-3a
N
N
L
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
16-4a
N
N
[L]
[C,M]
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by benthic
abundance values significantly depressed relative to
reference and bioassay exceedances of reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
16.5-1
[Y]
N
J
N
N
4
Sediment concentrations of As and Cu exceed CSL criteria
and minimal adverse biological effects indicated by diversity
value lower than reference.
16.5-2
N
N
N
N
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
17-1
[Y]
N
H.J.SDI
N
N
4
Sediment concentrations of As and Cu exceed CSL criteria
and minimal adverse biological effects indicated by diversity
values lower than reference.
17-1.5
Y
N
[L]
H
N
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by diversity
value lower than reference.
17-2
N
N
[L]
M
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by mollusc
abundance significantly depressed relative to reference and
echinoderm larval effective mortality significantly higher than
reference.
17-3a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
17-4a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
17.5-1
Y
N
[L]
H,J,S,SDI
Y
N
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by diversity
values lower than reference.
17.5-2
N
N
[L]
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
18-1 a
Y
[Y]
L
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As and individual PAHs exceed
SQS and CSL criteria, respectively, and minimal adverse
biological effects indicated by bioassay and benthic
abundance values significantly different from reference.
18-2a
N
N
[L]
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
18-2.5
N
N
[L]
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
18-3a
N
N
[A]
N/A
N/A
N/A
N/A
N/A
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by amphipod
mortality significantly higher than reference.
18-3.5
N
N
Y
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by results of
community structure evaluations.
18.5-1
N
N
[L]
M
TA,DA,TR
H,SDI
Y
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by community
structure evaluations, benthic richness and abundance
values, and bioassay results.
18.5-2
N
N
[L]
N
N
3
No identified exceedances of SQS chemical criteria, but
minimal adverse biological effects indicated by echinoderm
larval effective mortality significantly higher than reference.
19-1 a
N
N
N/A
N/A
N/A
N/A
1
No identified exceedances of SQS chemical criteria and
current biological impacts not suggested given lack of
significant differences from reference in bioassay responses
and benthic community structure.
19-2a
Y
N
M
N/A
N/A
N/A
N/A
4
Sediment concentrations of As exceeded SQS criterion and
minimal adverse biological effects indicated by mollusc
abundance significantly lower than reference.
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Inorganic
SQS?
Exceeds
Organic
SQS?
Bioassay SQS
Exceedances
Benthic SQS
Exceedances
Abundance &
Richness
Significant
Depressions
Diversity
Indices
Below
Reference
Community
Structure
Suggestive
of Impacts?
Species-
Level Data
Suggestive
of Impacts?
Impact
Category
Basis for Impact Category Designation
20-1 a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
20-2a
N
N
N/A
N/A
N/A
N/A
N/A
N/A
1
Biological data not available, but impacts not predicted
based on lack of sediment chemical exceedances of SQS
criteria.
Station Notes
a: Data obtained from the SFS (WESTON, 1993)
General Response Notes
N: No
Y: Yes
[ ]: Response exceeded chemical or biological CSL criteria
N/A: Data not available.
Bioassav Response Notes
A: Amphipod (Rhepoxynius abronius or Ampelisca abdita) bioassay
L: Larval (Crassostrea gigas or Dendraster excentricus) bioassay
P: Polychaete (juvenile Neanthes arenaceodentata) bioassay
Benthic Response Notes
C: Crustacean abundance
M: Molluscan abundance
P: Polychaete abundance
Abundance and Richness Notes
TA: Total abundance
DA: Dominant taxa abundance
TR: Total richness
DR: Dominant taxa richness
-------
Table C-1— Outcome of Preponderance of Evidence Approach for Marine Sediments
(Source: Roy F. Weston, Inc., October 1996, Table 7-1)
Station
Exceeds
Exceeds
Bioassay SQS
Benthic SQS
Abundance &
Diversity
Community
Species-
Impact
Basis for Impact Category Designation
Inorganic
Organic
Exceedances
Exceedances
Richness
Indices
Structure
Level Data
Category
SQS?
SQS?
Significant
Below
Suggestive
Suggestive
Depressions
Reference
of Impacts?
of Impacts?
Diversity Index Notes
H: Shannon-Weiner Diversity Index
J: Evenness Index
S: Simpson's Index
SDI: Swartz's Dominance Index
Impact Categories
1: No current impacts; future impacts not predicted
2: No current impacts; future impacts possible
3: Current minimal impacts (cause uncertain); future impacts possible
4: Current minimal impacts (sediment-related); future impacts possible
5: Current moderate to severe impacts; future impacts probable
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APPENDIX D
Comment Letters Received During the
Proposed Plan Public Comment Period
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Mr. Lee Marshall
Project Manager
U.S. EPA Region X (ECL-111)
1200 Sixth Avenue
Seattle, WA 98101
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Office of Response and Restoration
Coastal Protection and Restoration Division
c/o EPA Region X (ECL-117)
1200 Sixth Avenue
Seattle, Washington 98101
March 27, 2000
Subject: NOAA Comments on the Proposed Plan for the Asarco /
Sediments/Groundwater Operable Unit
Dear Mr. Marshall,
The National Oceanic and Atmospheric Administration (NOAA) appreciates the opportunity to
comment on the proposed plan for the Asarco groundwater and sediment operable unit.
Overall, we are pleased with the plan and support EPA's proposal.
General comments:
NOAA appreciates the efforts the two remedial project managers and ASARCO have made to
incorporate previous NOAA technical comments and suggestions into the overall cleanup of the
former ASARCO Smelter Facility, By combining parts of both operable units, it appears that
the sediment remediation will be accomplished sooner than originally scheduled and the use of
the upland disposal site for the Yacht Club sediments further streamlines the cleanup.
The natural resource agencies have expended considerable time and effort providing technical
advice to EPA, Ecology, ASARCO, and their consultants - this Proposed Plan suggests that it
was worth the effort since most of NOAA's previous concerns about the sediments have been
addressed. We want to encourage EPA, Ecology, and ASARCO to continue to seamlessly
integrate the sediment remediation with the shoreline stabilization. In this way, there should be
no wasted efforts between the two operable units cleanups and the impacts to the natural
resources will be minimized while the on-going exposures to contaminants will be curtailed
sooner rather than later.
NOAA strongly supports EPA's requirement for long-term monitoring of the remedy. Our
only concern with the proposed monitoring is that it does not include measuring contaminant
concentrations in the waters of Commencement Bay adjacent to the facility shoreline. As
explained in our section-specific comments below, we think that monitoring water quality in
Commencement Bay is critical and we recommend that EPA include offshore monitoring in the
final plan.
As we noted in our recent comments on the Nov. 1999 Explanation of Significant Differences
(ESD) for the Commencement Bay Nearshore/Tideflats Superfund Site (2 Feb. 2000), NOAA
has consistently based our evaluation of the Commencement Bay investigations and cleanup
plans on five basic principles:
A
-------
1. that cleanup(s) progress sooner rather than later to reduce continued exposure of trust
resources to contaminants;
2. a preference for complete removal of contaminants from the aquatic environment (most
contaminants originated from the uplands);
3. if the aquatic environment must continue to serve as the repository for the contaminated
sediments, we prefer that contamination not be transferred from impacted waterways to
otherwise clean areas for disposal; —
4. where remedial actions cause adverse impacts (during cleanup or disposal), mitigation for
lost natural resources or their services is required; and
5. cleanup and disposal decisions must be made under a baywide planning and evaluation
effort, especially for threatened/endangered trust resources and their habitats.
This Proposed Plan appears to satisfy our principles 1,2,3, and 5. Where mitigation is required
(principle 4) based on cleanup action details yet to be specified, we would strongly recommend
the enhancement of the nearshore/intertidal area immediately south of the slag peninsula along
Ruston Way, This could entail the removal of wood wastes from the bottom and re-contouring
to allow eelgrass propagation from the existing bed further south. We look forward to
reviewing a detailed Clean Water Act 404 analysis and/or mitigation plan.
Section-specific Comments:
Pg 2: Elements of the Preferred Alternative. Groundwater: The first item identifies limiting
groundwater "loading" to Commencement Bay as a remedial objective. The second item
identifies monitoring of groundwater as the method to document success or failure of the
remedy. However, the Groundwater-Sediments Task Force determined that two processes at
the site complicate calculations of contaminant loading to Commencement Bay from
discharging groundwater:
(1) Tidal cycles in Commencement Bay cause significant fluctuations in the hydraulic
gradient at the CB shoreline; these tidal waters intermittently enter the fractures in the slag along
the shoreline and mix with discharging groundwater, altering the groundwater gradient,
discharging water volumes and the concentration of conservative constituents, such as chloride
(CI); and
(2) The solubility of the metal and metalloid (e.g., arsenic) ions that are contaminants of
concern at the site varies with changes in pH and/or redox conditions, both of which are altered
as the groundwater mixes with saline, oxygenated seawater within the fractured slag before
discharging into Commencement Bay. These processes are described at the bottom of page 7
in the Proposed Plan, also,
COMMENT: Because measurements of groundwater gradients and contaminant concentrations
in upland wells are an incomplete predictor of the contaminant loading to Commencement Bay
(as explained above), and the dilution from tidal mixing at the shoreline is significant but not
precisely quantified; the only way to determine if the shoreline water of Commencement Bay is
not contaminated by the metal and metalloid contaminants from the site is to sample the
shoreline waters of Commencement Bay and analyze for these constituents.
Pg 5: State Sediment Management Standards - Sediment Cleanup Criteria:
BASIS: Numerous sediment samples at the site had extremely high concentrations of metals
and metalloids, variable laboratory bioassay results, and benthic community analyses that did
not show any statistically significant differences from reference. The apparent absence of the
Page 2
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expected response (mortality leading to benthic community alterations) at these stations may
result from the physical structure of the slag that contains most of the contamination.
However, very high concentrations of contaminants remain at the site, and ecological indicators
of an adverse response to these contaminants were varied. The toxicity of some of these
contaminants can change with changing environmental conditions, e.g. temperature or oxygen
availability, and toxicity can vary by organism lifestage. Therefore, it is important that areas
where high concentrations of contaminants remain in contact with ecological receptors are
monitored over the long-term to demonstrate continued ecological protectiveness.
COMMENT: NOAA supports the proposal not to require active remediation of these areas on
the condition that EPA require long-term monitoring to demonstrate whether this decision
continues to be protective. It is recommended that this monitoring be coordinated with the
long-term monitoring of benthic communities in remediation areas that are dredged and/or
capped to make efficient use of equipment and labor.
Pg. 7, Sec. 3.1 Groundwater: "Groundwater at the Facility flows from the southwest to
northeast and ultimately discharges to Commencement Bay."
COMMENT: Because Commencement Bay is the ultimate recipient of the contaminated
groundwater, and because ecologic receptors along the Commencement Bay shoreline can be
adversely affected by these contaminants, NOAA supports the preferred remedy on the
condition that long-term monitoring of the site include collection of shoreline water samples for
contaminant quantification.
Pg. 8, Sec. 3.1 Groundwater: "DMA-related organic compounds are also present in the
shallow groundwater system. However, the DMA, arsenic, and copper in the DMA area do
not appear to result in any greater exeeedances of surface water criteria in the adjacent
Commencement Bay than observed elsewhere at the Facility. For this reason, no special
groundwater remedial action is planned for the DMA area. However, groundwater monitoring
in the DMA area will be part of the post-remedial action monitoring program."
COMMENT: NOAA can support a decision not to take action to reduce contaminants in
groundwater at the DMA area, only if there will be long-term monitoring of the receiving water
along the shoreline of Commencement Bay where NOAA trust resources are potentially
affected by these contaminants, and with a commitment that if the monitoring data indicate this
decision is not protective of the environment, that other remedies will be evaluated for the DMA
area.
Pg. 10, Sec. 3.2, Sediment: "Some concentrations of metals and/or biological impacts (as
measured with bioassays) exceeded the CSL outside of the Contaminant Effects Area in what is
depicted as the "Moderate Impact Area" (Figure 5). The benthic communities in the Moderate
Impact Area appear healthy. Because active cleanup might result in greater net negative impacts
through destruction of existing habitats than if not remediated, long-term monitoring is
proposed in these areas to verify that the overall health of the ecosystem (after the upland and
offshore cleanup activities are completed) is remaining the same or improving."
COMMENT: NOAA supports the proposal not to require active remediation of these areas on
the basis that EPA will require long-term monitoring to demonstrate whether this decision
continues to be protective. It is recommended that this monitoring be coordinated with the
Page 3
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long-term monitoring of benthic communities in remediation areas that are dredged and/or
capped to make efficient use of equipment and labor,
Pg. 13, Sec. 5.2, Ecological Risk Assessment. Groundwater: "The findings of the Task Force
regarding the impact of groundwater on the sediments and waters of Commencement Bay
indicate the following:
The amount of metals currently being discharged (pre-remediation conditions) by"ground-
water and surface water discharges to Commencement Bay results in the exceedance of
applicable water standards for certain metals (e.g., arsenic and copper) within a few feet of
the shoreline. The metals load discharged to Commencement Bay by groundwater is
expected to decrease after remediation because the most highly contaminated source
materials will have been removed and groundwater flow to Commencement Bay will be
reduced."
COMMENT: NOAA agrees with EPA's assessment and strongly supports all efforts to reduce
groundwater flows through the site which would continue to transport metals into the marine
environment. Early interception of the groundwater upstream of the site should be maximized ,
the placement of an impervious cap over the site to eliminate surface water percolation
downward then seaward is imperative, and co-precipitation treatment of collected runoff waters
on site should be emphasized, if this technique removes significant levels of metals. However,
we want to emphasize that the only means to ascertain whether the remedial actions have
reduced the discharge of metals (and metalloids such as arsenic) along the shoreline of
Commencement Bay to bring them into compliance with applicable water standards is to
include sampling of the shoreline water of Commencement Bay in the post-remediation
monitoring. Only a well-designed sampling plan can demonstrate to all parties that the selected
remedy has caused shoreline areas to achieve the applicable water quality criteria.
pg. 15, Sec 6.1, Groundwater Cleanup Objectives:
• "Prevent discharge (to Commencement Bay) of groundwater that exceeds applicable marine
surface water quality standards or background concentrations (if background
concentrations are higher than the standards)."
AND: "The cleanup goal of 3.1 ug/L for copper is protective of human health and marine life
in Commencement Bay. It is acknowledged, however, that the background concentration for
copper in the vicinity of the Facility is 40 ug/L, and it may not be possible to achieve the 3,1
ug/L cleanup goal. If not, copper in groundwater will be managed to the 40 ug/L background
concentration."
COMMENT: These statements are ambiguous. The information provided above documents
that the (upgradient groundwater) background concentration for copper is higher than the acute
and chronic ambient water quality criteria. On the basis of the wording of the Groundwater
Cleanup Objective, this would indicate that for copper in groundwater the cleanup objective is
40 ug/L. However, the ecologic receptors and the applicable criterion apply to waters of
Commencement Bay. It is questionable whether a remedy that does not lead to compliance
with the water quality criteria is ecologically protective, and it is possible that even if the
groundwater copper concentration is controlled to 40 ug/L, that the shoreline waters of
Commencement Bay will not meet the water standard. There are other sources of copper (and
other metals and metalloids) contamination along the shoreline such as contaminated surface
water runoff and the large deposits of slag, but these sources also are affected by former
actions of Asarco.
Page 4
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It is the position of NOAA, as the federal Natural Resource Trustee for marine
organisms and habitats, that a goal of the overall remedy should be the attainment of water
quality criteria for the protection of marine life in all areas of Commencement Bay affected by
former site smelting, manufacturing, and/or disposal activities.
Pg. 16, Sec 6.1, Groundwater Cleanup Objectives:
"Long-term monitoring"
COMMENT: NOAA recommends that this be amended to read; "Long-term monitoring of
groundwater and (Commencement Bay) receiving water" in order to demonstrate that the water
column used by marine organisms along the shoreline of Commencement Bay is protected by
the remedy.
Pg. 21, Sec 7.1 Groundwater: "No remedial action is planned for the Slag Peninsula area
(approximately 85,000 yd2 or 17.5 acres) because the water depths and steep slopes make
capping or dredging technically impracticable."
COMMENT; NOAA supports EPA's position of not trying to actively remediate the steep
portions of the Slag Peninsula Unit located in deep water. Conventional capping techniques do
not appear to be productive because of the steep slopes and water depths. NOAA prefers
intertidal and shallow subtidal capping to be placed only when equivalent (or more) fill is
removed so that there is no net loss of aquatic habitat; for that approach to be used on the slag
peninsula it would require the removal of too much of the peninsula before reaching gentle
enough slopes for the capping material to repose in perpetuity. We are unaware of any other
cost-effective and environmentally-sensitive remediation technology to solve these problems.
Pg. 22, Sec. 8.1 Overall Protection of Human Health and the Environment. Groundwater:
There isn't any discussion of how the range of alternatives will protect the environment of
Commencement Bay, which receives the discharging groundwater. The marine habitat of
Commencement Bay is composed of the waters of Commencement Bay as well as the
sediments.
Pg- 23-24, Sec. 8.2 Compliance with Federal and State Environmental Standards,
Groundwater: "Samples of Commencement Bay water collected at the shoreline confirm that
current laws for marine water quality are not currently met at all locations and at all times.
However, metals concentrations in groundwater flowing toward the shoreline are expected to
decrease in future years in response to the site-wide changes (i.e., reduced groundwater
discharge) affected by the cleanup. These changes are expected to allow state and federal laws
to be met at the end of the remedy."
COMMENT: NOAA agrees with the preceding analysis and believes that monitoring of water
quality along the shoreline, where contaminated slag will remain in place, is necessary to
demonstrate that the remedy has resulted in compliance with Federal and State Environmental
Standards for the waters (and habitats) of Commencement Bay. NOAA recommends that the
Washington State Water Quality Criteria for protection of marine life be utilized as benchmarks
for protection of the water column component of marine habitat.
Pg. 25, Sea 8,3, Long-Term Effectiveness and Permanence. Sediment: NOAA agrees with
the analysis in the Proposed Plan and supports the preferred approach which is to dispose
dredged contaminated sediments in the upland containment facility with other contaminated
Page 5
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materials. The consolidation of contaminated site materials into a few engineered upland
facilities is expected to make long-term operation, maintenance and monitoring of these
disposal facilities more efficient and reliable than would disposal into near-shore or sub-aquatic
disposal facilities,
Pg. 29, Sec, 9.2.1 In Situ Sediment Capping: "In situ capping is the Preferred Alternative for
the Nearshore/Offshore area and Northshore area. Approximately 88,000 sq. yd. (IB acres)
of existing contaminated sediments in the Nearshore/Offshore area will be capped with a
minimum of 1 meter of clean sediment from an upland source and approximately 7,000 sq. yd.
(1.5 acres) of existing contaminated sediments in the Northshore area will be capped with a
minimum of 1 meter of clean sediment. The cap thickness will be designed such that it
provides chemical isolation, is stable, and provides a cap surface that will allow recolonization
of benthic communities."
COMMENT: While NOAA was originally pessimistic about the feasibility of capping the
contaminated sediments in the remaining Nearshore and Offshore Units, the initial results of
the Pilot Project supports this approach. Obviously, a fairly coarse material (sand and gravel)
will be needed; such materials are often low in organic content(usually in the silt and clay
fractions). However, it would be desirable if there is some way that increased organic content
could be incorporated into the capping material to enhance biological repopulation. This is a
challenge since the organics are usually associated with the finer components which can be
swept away by the currents during emplacement, EPA should keep the goal of benthic
recolonization in mind during design.
NOAA believes that nothing less than a 1-meter cap will effectively isolate contaminated
sediment at the ASARCO site. One of the objectives for the sediment component of the remedy
is "Restore and preserve aquatic habitats by limiting and/or preventing the exposure of
environmental receptors to sediments with contaminants above Washington State Sediment
Management Standards (SMS, WAC 173-204)" (See bottom of pg. 16). In order to
accomplish this goal, the habitat value of the sediments must be restored. It is likely that
burrowing organisms will recolonize the cap material soon after it is placed, as occurred in the
pilot study cap at the site (see the monitoring reports prepared for Asarco by Parametrix, Inc.).
One organism thought to inhabit the sediment offshore of the Asarco facility is a ghost shrimp
(also called mud shrimp). This organism is known to construct burrows 2 feet deep (Garman,
personal communication). Other researchers report that ghost shrimp burrow to a depth of
three feet (Ricketts and Calvin, 1962). Bases on this information, we conclude that one meter
is the minimum cap thickness that would be effective. It is necessary to isolate contaminated
sediment from ghost shrimp and other burrowing organisms to prevent the biota from
facilitating transfer of the contaminants to the sediment surface, the water column, and to
higher trophic level organisms.(G. F. Riedel et. al., 1989).
Pg. 30, Sec. 9,2.2 Yacht Basin: "For the dredging alternative, the material would be
dewatered, and then placed in a controlled, upland location (known as Crescent Park, in the
central part of the upland Facility), that will be monitored for many years. This allows for the
long-term effectiveness of the remedy to be monitored. Further, the mobility of the
contaminants would be reduced, as the sediment would be in a location that does not have
contact with water. There will also be contingency plans should the upland cap begin to fail
(i.e., get cracks in it)."
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COMMENT: NO A A supports the preferred alternative because it permanently removes
contamination from a site area that is perturbed by marina activities and only dredging to
remove the contamination will allow the marina to continue operations in the future without
restrictions on dredging. In addition, isolating the contaminated materials in an upland facility
with contingencies for any incipient failure of the containment structure should be easy to
monitor and implement because these upland site areas also will be used for isolation of
contaminated soils and/or debris, -
I hope that these comments are useful to you in reaching a final decision for the cleanup of
contaminated groundwater and sediments at the Asarco facility. We look forward to reviewing
the design, and especially wish to review the monitoring plan. If you have any questions about
NOAA's comments, you may contact me (206/553-2101) or Gayle Garman (206/526-4542).
ce: Alyce Fritz, NO A A/ NOS, file copy
Gayle Garman, NOAA/NOS
Robert Clark, NOAA/ NMFS/RC
Robert Taylor, NOAA/GCNR
Rachel Friedman, NOAA/N MFS/HCD
Jeff Krausmann, USFWS
Judy Lantor, USFWS
Michelle Wilcox, WA Dept. of Ecology
John Carleton, WDFW
Bill Graeber, WDNR
Bill Sullivan, Puyallup Tribe
Glen St. Amant, Muckleshoot Tribe
Sincerely,
Helen Hillman
Coastal Resource Coordinator
Page 7
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REFERENCES:
Garman, G., NOAA Coastal Protection and Restoration Division, 2000. Personal
communication. March 24.
Ricketts, Edward F. and Jack Calvin. 1962. Between Pacific Tides: 3rd Edition revised by
Joel W. Hedgepetb. Stanford University Press, Stanford California, pp 264-265.
Riedel, Gerhardt F., J. G. Sanders and R. W. Osman, 1989. "The role of three species of
benthic invertebrates in the transport of arsenic from contaminated estuarine sediment." J.
Exp. Mar. Biol. Ecol. (134) pp. 143-155.
Page 8
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received
Thomas L. Aldrich
Site Manager
Tacoma Plant
March 27, 2000
Mr. Lee Marshall
U.S. Environmental Protection Agency, Region 10
1200 Sixth Avenue, ECL-113
Seattle, WA 98401
RE: Response to EPA's Proposed Plan
Asarco Sediments/Groundwater Operable Unit
Surface Water Drainage and Control - (1103)
Dear Mr. Marshall:
In January EPA submitted a Proposed Plan for the sediments/groundwater clean up. Attached
are Asarco comments. Asarco appreciates the opportunity to work with EPA and resolve any
outstanding issues on the Preferred Alternative.
Please contact Dave Nation or me to further discuss these issues.
Enclosures
cc: Bruce Cochran - Washington Dept. of Ecology
David Nation, Hydrometrics
Doug Holsten, CH2M Hill
Don Weitkamp & Jim Good, Parametrix
Very truly yours,
ASARCO Incorporated
Thomas L. Aldrich
Site Manager
ASARCO Incorporated P.O.
INFORMATION CENTER
email:
Box 1677 Tacoma, WA 98401 (253)756-0201
(253) 756-5436 FAX: (253) 756-0250
TLAIdrich@compuserve.com
-------
RECEIVED
APR 0 3 2000
Asarco Comments on: Environmental
EPA's
Asarco Sediments and Groundwater Proposed Plan
(January 2000)
General Comments
Overall, the Proposed Plan and Preferred Alternative for sediment and groundwater looks
very much like what Asarco and EPA have been working towards for a long time. However,
there are several areas of the Proposed Plan that should be clarified or revised to make the
Plan more easily implemented while maintaining the protectiveness of the Plan. The main
areas where Asarco believes the Proposed Plan should be improved are:
1. Definition and identifications of impacted sediment areas
2. Sediment cleanup objectives
3. Sediment cap thickness
4. Sediment monitoring requirements
5. Source of sediment capping material
6. Arsenic and copper Remedial Goals and compliance point
7. Need for additional groundwater capture
8. Treatment of surface water baseflows
Definition and Identification of Impacted Areas
As Asarco understands the Expanded RI/FS data and the Proposed Plan, all impacted areas
that require remediation and can practicably be remediated will be remediated. However, the
use of the terms "moderately impacted" and "minimally impacted" in the Proposed Plan are
potentially misleading and may imply that some impacted areas will not be remediated.
These terms also seem to ignore the sophisticated approach that EPA and Asarco have taken
to identify and characterize areas with contaminant effects. Asarco would prefer that areas
simply be identified as "impacted" and "non-impacted" as determined by the preponderance
of evidence approach and the extensive sediment effects data.
The approach to identification of impacted areas presented by Asarco in Phase 1 of the
Expanded RI/FS was substantially more complex and complete than the approach described
in the Proposed Plan. In comparison to the Phase 1 approach, it is extremely simplistic to use
"...benthic results...to identify the most highly impacted areas...". Asarco prefers to base
impact determinations on all of the detailed sampling and data analysis work that Asarco and
EPA have conducted rather than the highly simplistic approach described in the Proposed
Plan, which is only a slight modification of the Sediment Management Standards (SMS).
In Phase 1, Asarco evaluated measures of chemistry, bioassays, benthic community results
and other types of sampling (e.g., pore water chemistry, pore water bioassays, tissue
chemistry, sequential extraction analyses of slag) to determine those measures that appeared
to be most highly correlated. The benthic results were evaluated in many ways including
relatively simplistic SMS measures and much more powerful data analysis tools (e.g.,
proportional similarity index and principal coordinates analysis). All of these measures were
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evaluated and chemistry, sediment bioassays, and numerous measures of benthic abundance
and diversity were used in the final preponderance-of-evidence approach. In this approach,
some benthic community measures were given greater weighting than other benthic
measures, sediment bioassays, and chemistry. Bulk sediment chemistry results were given
the least weight in the preponderance-of-evidence approach. Some other evidence was
judged to be inappropriate for use in cleanup decisions.
The purpose of the preponderance-of-evidence approach was to define those areas exhibiting
contaminant effects. No "moderate impact areas" were defined in the Phase 1 Report. The
preponderance-of-evidence either "tipped the scale" into contaminant effects designation or it
did not. Thus, one significantly different bioassay result or a particularly high chemistry
result does not indicate a "moderately impacted" area. In such cases, the preponderance of
other evidence (mainly various measures of the benthic community) indicates that this area is
not impacted. Defining stations that have one significantly different bioassay and/or
chemistry result as "moderately impacted" ignores all of the evidence presented in the Phase
1 and 2 Reports that clearly indicate the effects of slag may confound typical SMS
interpretations of bioassay and particularly bulk sediment chemistry results. The
preponderance-of-evidence approach was not designed to define "in between" or
"moderately impacted" areas (see Responses to comments on Phase 1 Report). Consequently,
Asarco has never agreed to the proposed definitions of moderately impacted areas.
In the Proposed Plan, the only areas that receive the designation "non-impacted" are those
that do not exceed the bulk sediment chemistry Sediment Quality Standard (SQS). Asarco
has collected and reported a vast amount of information indicating that where slag particles
are present, bulk sediment chemistry is often irrelevant to the actual toxicity of the sediments.
Some sediment stations at the Asarco site were well above the SQS and showed no other
evidence by any measure of contaminant effects, yet in Section 5.2 of the Proposed Plan
these stations are defined as "minimally impacted". Because there is no evidence of
contaminant effects, it is inappropriate to define these stations as impacted in anyway.
The reason described for the minimal impact designation is that the sediments "...may have
impacts in the future..However, EPA provides no scientific evidence to clarify what action
or event might reasonably be expected to cause these sediments to have impacts in the future.
There is no evidence available from any of the numerous studies completed to support this
supposition of potential future impacts. All available information, particularly regarding slag
metals availability (e.g., the sequential extraction analysis) and the present healthy state of
the benthic community, do not support this supposition. Because there is no evidence that
these sediments would reasonably pose future impacts, these sediments should be designated
as "non-impacted".
Similarly, Asarco does not agree that stations with "minor biological CSL exceedances"
should be designated as "minimally impacted". As stated in the previous comment, Asarco
believes this simplistic approach ignores the preponderance of evidence for these stations (all
the other benthic and/or bioassay measures) that indicate these stations are not impacted in
any way. These stations should also be designated as "non-impacted".
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Finally, consistent with the above comments, the remediation area should be defined simply
as "impacted stations" not "severely impacted stations."
Sediment cleanup objectives
The Proposed Plan describes the sediment clean up objectives for remediation as the State
Sediment Management Standards (SMS). Asarco agrees that the SMS may be a useful
relatively simple initial measure that can be used as a guideline of the success of the
remediation. However, it should not be the sole determination of whether the remediation is
successful as defined in Section 6.2 of the Proposed Plan.
As discussed above, the SMS uses bulk sediment chemistry, bioassays, and relatively
simplistic measures of benthic abundance. Both the data analysis presented in the Phase 1
Report and EPA's own methodology for determining contaminant effects areas presented in
the draft Proposed Plan go beyond the simple SMS approach. It is therefore unreasonable to
go back to the SMS approach when evaluating the success of remediation.
If the physical and chemical properties of the sediments (e.g., particularly slag particles) can
confound the determination of cleanup areas, they can certainly confound the determination
of cleanup success. To be consistent with all of the knowledge gained on Asarco sediments
over the years, an achievable reasonable sediment cleanup objective must allow for these
potentially confounding effects and go beyond a simple SMS type approach.
Asarco recommends that a preponderance of evidence approach as presented in the Phase 1
Report be used to determine the cleanup success. Because this approach may require
extensive sampling and data analysis, cleanup success could be determined through a tiered
process. The tiered process would use progressively more complex and accurate analyses to
determine whether the sediments have indeed been cleaned up similar to PSDDA and the
SMS itself. One possible approach would be as follows:
Tier 1. Compare bulk sediment chemistry to SQS values. If sediment chemistry is
below SQS, then cleanup objective has been met. If sediment chemistry is
above SQS, proceed to Tier 2.
Tier 2. Conduct bioassays (suite to be determined) and compare results to reference
sediments (similar to SMS). If bioassays not significantly different (exact
criteria to be determined) from reference, then the cleanup objective has been
met. If bioassays are significantly different, then proceed to Tier 3.
Tier 3. Conduct benthic community analysis and analyze various measures (to be
determined but similar to Phase 1 Report) of abundance and diversity. (In this
case the simple SMS benthic measures might be used but some other more
complex data analysis must also be included).
Immediately after cap construction, only Tiers 1 and 2 could be used, because no benthic
community would be present. However, recourse to Tier 3 would be available several years
after construction.
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In addition, the use of the word "prevent" in the cleanup objective definition appears to be
inappropriate. Asarco agrees that the exposure of receptors to contaminant effects can be
"limited" or "minimized". However, cleanup success should not be measured in terms of
absolute prevention of all exposure to contaminants to all potential receptors. It is possible
that minor exposures might take place, but in overall terms the remediation would still be
successful. The success of the remediation should be measure in terms of whether the entire
cleanup meets the overall goals of protection of human health and the environment.
Sediment cap thickness
EPA's Proposed Plan for the Asarco Sediments/Groundwater Operable Unit provides for
sediments to "be capped with a minimum of 1 meter of clean sediment from an upland
source." None of the information Asarco has developed during the sediment investigations
justifies the "minimum of 1 meter" thickness. Asarco is concerned that EPA has specified a
considerably thicker cap than is necessary for protection of the environment of
Commencement Bay and human health.
EPA proposes a minimum cap thickness rather than a nominal cap thickness as well as an
increase from the 0.6 m (60 cm or 2 ft) cap proposed in the Refinement of Remedy
(Parametrix, 2000) to the thicker 1 m cap. These increases represent almost twice as much
cap material as originally considered by Asarco and evaluated in the pilot cap tests. Thus, the
EPA proposal would be considerably more expensive than the Asarco proposal of a nominal
cap thickness of 0.6 m.
No evidence has been provided by EPA that the considerably thicker cap will provide greater
protection of the environment in Commencement Bay. Requiring the minimum cap thickness
of 1 m requires technical or scientific justification that this increase would provide a
substantial increase in protection. No such justification has been provided by EPA or any
other entity in the Asarco Sediments evaluations. It appears then, that EPA's requirement for
a minimum 1 meter cap is arbitrary, capricious and beyond the scope of the agency's
authority given the persuasive evidence for a nominal 0.6 meter cap in the pilot study. Also,
under the National Contingency Plan, selected remedies are required to be cost- effective. If a
remedy is both protective of human health and the environment, and meets ARARs, it must
also be cost-effective. 40 CFR § 300.430(f)(l)(ii)(D). Under the regulation, cost-
effectiveness is determined by evaluating three criteria - long-term effectiveness and
permanence, reduction of toxicity, mobility or volume through treatment, and short-term
effectiveness. One then compares overall effectiveness with cost to see whether the cost is
proportional to effectiveness. Both a nominal 0.6 meter cap and a minimum 1 meter cap are
protective of human health and the environment and meet ARARs. However, the cost
increase attributable to the minimum 1 meter cap is disproportionate to its effectiveness
given that the nominal 0.6 meter cap is equally effective. If the remedy is not cost-effective,
EPA can't select it.
The rationale for requirement of a minimum cap thickness of 1 m appears to have its origins
in the Navy Homeport deliberations of the 1980's. At that time, deepwater disposal and
capping of Everett Harbor sediments dredged from the Homeport site was proposed.
008\1103\word\Asarco Resp.doc
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Opponents to this action maintained that a minimum cap thickness of 1 m should be required
to eliminate any potential that the contaminated harbor sediments would be exposed if ghost
shrimp should burrow into the cap. This was based on the theory that ghost shrimp can
burrow up to nearly 1 m deep, and that their burrowing would move sufficient quantities of
contaminated sediments to the surface to incur a risk to the marine environment.
Asarco has searched, but been unable to find factual information that supports this concern.
There appears to be a misconception that the burrowing shrimps (ghost shrimp and/or blue
mud shrimp) are a demonstrated threat to a sediment cap in Puget Sound. The potential threat
of these shrimp is that their burrowing activities will lead to sufficient contaminated sediment
redistributed to the surface layers of the cap to raise contaminant levels above biological
effects concentrations. This would require the shrimp to:
• burrow to depths that would penetrate well into the existing sediments or
• actively burrow within the contaminated sediments moving large volumes of the
contaminated sediment to the surface, or
• pump large amounts of water through the contaminated sediments extracting
substantial concentrations of metals.
None of these actions are probable.
It is valuable to review what is known about the local species of burrowing shrimp. There are
two species of subtidal burrowing shrimp in Puget Sound, ghost shrimp (Neotrypaea
californiensis formerly Callianassa californiensis) and the blue mud shrimp (Upogebia
pugettensis). Neotrypaea lives primarily at middle intertidal levels, commonly decreasing in
abundance at lower intertidal elevations due to predation (Posey 1985, Posey 1986,
Swinbanks and Luternauer 1987). Upogebia also tends to be intertidal but is found
commonly at lower elevations. Both species are also found in subtidal areas. Neotrypaea is a
deposit feeder that actively burrows in the top 10 cm of the sediments where it also
constructs a single less active extension of its burrow generally about 30 cm deep, but
sometimes as deep 40-50 cm (Swinbanks and Murray 1981). Upogebia is a filter feeder that
forms a lined burrow that remains constant over time. Its burrow is Y shaped with the lower
extension reaching as deep as 50-60 cm. Upogebia appears to actively pump water through
the U shaped upper portion of its burrow to obtain food.
To our knowledge there have been no investigations demonstrating that sufficient numbers of
ghost shrimp are likely to burrow to sufficient depths and move sufficient material to
represent any demonstrated risk to the marine environment. We believe it is more likely that
small numbers of ghost shrimp might burrow as deep as 60 cm in a cap, and that if they did
the quantity of material they would move would not raise surface concentrations of metals to
near the sediment quality standards. Upogebia does pump water through the upper portions
of its burrows to provide food and oxygen. Because its burrows are lined and the active
pumping is likely restricted to the upper U shaped portion of their burrows, there is little
reason to expect that this water flow would extract measurable levels of contaminants even if
the bottom of the burrow did extend into contaminated sediments.
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Asarco has been unable to find any reports of burrowing shrimp actually changing the
contaminant concentrations of sediments within a cap, or at the surface of a cap. The concern
for contaminant redistribution appears to be theoretical rather than demonstrated.
Asarco also believes there is little risk in providing a 60-cm cap. Additional cap material can
be added at a later date if monitoring determines there is actual evidence that ghost shrimp or
other means are moving contaminants to the upper layer of the cap. The Proposed Plan (page
31) provides for the addition of material if monitoring indicates additional material is
warranted.
References
Posey, M.H. 1985. The effects upon the macrofaunal community of a dominant
burrowing deposit feeder, Callianassa calif "orniensis, and the role of predation
in determining its intertidal distribution. Dissertation, University of Oregon,
Eugene, OR. 119 p.
Posey, M.H. 1986. Predation on a burrowing shrimp: Distribution and community
consequences. Journal of Experimental Marine Biology and Ecology.
103:143-161.
Posey, M.H., B.R. Dumbauld, D.A. Armstrong. 1991. Effects of a burrowing mud
shrimp, Upogebia pugettensis (Dana), on abundances of macro-infauna.
Journal of Experimental Marine Biology and Ecology. 148:283-294.
Swinbanks, D.D., J.L. Luternauer. 1987. Burrow distribution of thalassinidean shrimp
on a Fraser Delta tidal flat, British Columbia. Journal of Paleontology.
61:315-332.
Swinbanks, D.D., and J.W. Murray. 1981. Biosedimentology zonation of Boundary
Bay tidal flats, Fraser River Delta, British Columbia. Sedimentology 28:201-
237.
Thompson, R.K. and A.W. Pritchard. 1969. Respiratory adaptations of two burrowing
crustaceans, Callianassa californiensis and Upogebia pugettensis (Decapoda,
Thalassinidea), Biological Bulletin. 136:274-287.
Sediment Monitoring
Asarco agrees that monitoring of remediated areas is needed to verify cleanup success.
However, Asarco does not believe that extensive long-term monitoring of other areas is
necessary and believes the cost of this monitoring is substantial given the limited benefit of
monitoring non-remediated areas. Asarco believes that EPA's proposed plan for this
sampling implies that the RI/FS process was somehow incomplete and that contaminant
effects area have not been adequately identified. This is not true. In fact, Asarco and EPA
have come to a consistent and scientifically supported decision on areas exhibiting
contaminant effects. Asarco also believes that monitoring constitutes a remedial action for
008\1103\word\Asarco Resp.doc
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these areas and that EPA does not have authority under CERCLA to require actions for these
non-impacted areas.
The Proposed Plan indicates that monitoring of areas outside remediation units will be
conducted to "...confirm the assumptions and conditions..." used to make clean up
decisions. The Plan further indicates that based on this monitoring, some further action may
be needed. Sediment sampling to "confirm assumptions and conditions" regarding areas and
volumes of sediments that may exhibit contaminant effects was conducted during the RI and
FS studies consistent with Superfund Guidance. The primary purpose of the Expanded RI/FS
process was to determine those areas that exhibit contaminant effects, and therefore, require
remediation. Prior to conducting the Phase 1 sampling, an extensive monitoring plan was
developed with the full participation of EPA and its consultants including methods for
evaluating the results of that sampling. It was agreed at that time that a "preponderance-of-
evidence" approach would be used to evaluate the numerous types of sampling and data
analysis that were conducted. This original concept is entirely consistent with the Superfund
RI process, which should define the areas and volumes of contaminated materials to be
remediated. It has been Asarco's position since completion of the Phase 1 Report that the
sampling and analysis effort provided more than sufficient information to determine areas
where action such as remediation is needed (with some exceptions in the marina and north
shore areas, which were addressed in subsequent sampling).
Under CERCLA Section 104, EPA can take action when a hazardous substance is released
into the environment or threatened to be released. EPA can also take action if a there is a
release or threat of a release of a pollutant or contaminant which may present an imminent
and substantial danger to the public health or welfare. A "pollutant or contaminant" is
anything that, when released into the environment and "upon exposure, ingestion, inhalation,
or assimilation into any organism, either directly from the environment or indirectly by
ingestion through food chains will or may reasonably be anticipated to cause death,
disease ..." or problems with the organism or offspring. 42 USC § 9601(33).
The metals in the sediments outside the contaminant effects area have not been released (they
are in the slag matrix), nor are they likely to be released. Moreover, the metals in sediments
are not pollutants or contaminants because they are not causing effects. If there is neither a
release nor a threatened release of hazardous substances, contaminants or pollutants, the
agency cannot compel remedial or response action.
Source of capping material
The Proposed Plan specifies an upland source of capping material. There is no justification
for specifying that the cap material be derived "from an upland source" and nothing that
should preclude an aquatic source of material. Cap material from an aquatic source would be
as suitable or more suitable than material from an upland source for biological colonization.
There should be no difference in the effectiveness of contaminant isolation with either an
upland or an aquatic source. Appropriate material may be available at a lower cost from a
marine source. Asarco believes the location and selection of capping material is a Remedial
Design task and that the Proposed Plan should not preclude aquatic sources of capping
material.
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Dredging depth in the marina
The Proposed Plan describes dredging to a depth of approximately 2 feet. This is an
acceptable depth to use to develop a conservative estimate of dredging volume. However, it
needs to be made clear that actual dredging depth will depend on the actual depth of
contamination that is verified to be present during Remedial Design and during actual
dredging. There is no evidence of sediments exceeding cleanup screening levels (CSLs)
below a depth of 1 ft in the marina.
As part of the Phase 2 Expanded RI/FS, subsurface sediment chemistry core samples were
collected by divers at stations 5-0 and 5.5-0 in the yacht basin (Parametrix 1996). The upper
layer of sediment that contains metals higher than CSLs was visually distinctive from the
deeper sediments that did not exceed CSLs. Cores were observed to contain black sand in the
upper 0.4 ft and gray sand from 0.4 to 1.9 ft. Core samples from the upper 1.0 ft exceeded
CSLs for arsenic, copper, and zinc. Samples from 1.0 to 1.9 ft were below CSLs.
Divers collected two additional core samples from the shallow, shoreward side of the basin in
1997. Rather than dividing the cores into 1 -ft segments, these cores were sectioned according
to visually distinctive changes in sediment type. The core from station 5-0.9 was described as
a dark olive colored sandy gravel in the upper 17 cm (0.6 ft). The 17 to 18 cm section was
gravel with shell debris. Copper exceeded the CSL in the upper section and all metals tested
were below CSLs in the 17 to 18 cm section. The other core sample contained olive colored
fine sand in the upper 21 cm (0.7 ft). The 21 to 37.5 cm section (0.7 to 1.2 ft) was silty sand
with gravel and cobbles. The upper section exceeded CSLs for copper and mercury and the
lower section was less than the CSLs for all metals analyzed.
Additional core samples will be collected in the spring of 2000 as part of the preliminary
design analyses for yacht basin dredging. These analyses will help determine whether metals
exceeding CSLs are limited to the upper 1 ft of sediments, or if deeper sediments exceed
CSLs in any areas of the yacht basin.
Arsenic and Copper Remedial Action Objectives, Remediation Goals, and Compliance
Points
Asarco strongly prefers that the Preferred Alternative and Proposed Plan result in attainment
of Remedial Action Objectives and Remediation Goals (RGs). Asarco's primary concerns
regarding the attainment of RAOs and RGs are:
1. The Remedial Action Objectives for groundwater do not match the RAOs of the
Asarco Tacoma Smelter Facility Record of Decision ("Upland") ROD. Since the
remedial action is being, and will continue to be, implemented as part of the
Upland ROD, it appears that the remedial action must "serve two masters".
2. RAOs are overly broad and ignore site-specific information about the risk from
arsenic.
3. The compliance point for attainment of RGs is not specified. Depending on
location of groundwater compliance points the RGs may not be attainable.
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To remedy these concerns, Asarco proposes that:
• the RAOs for groundwater in the Proposed Plan should complement the RAOs for
groundwater in the Upland ROD;
• the RG for arsenic should be based on EPA's Site-specific risk assessment that
indicates existing groundwater discharges to Commencement Bay do not cause
unacceptable risks to human health and the environment; and
• the compliance point for groundwater discharges should be identified as the point
of discharge (i.e., post-remedial action groundwater/seawater interface).
Specifically, Asarco proposes the following groundwater RAOs:
1. Prevent ingestion of potable groundwater containing concentrations above Federal
MCLs and direct contact with groundwater containing contaminants in
concentrations above risk-based goals.
2. Reduce discharge to Commencement Bay of groundwater that exceeds applicable
marine surface water quality standards, risk-based levels protective of human
health, or background concentrations (if background concentrations are higher
than the standards).
Asarco proposes an arsenic remediation goal of 0.012 mg/L based on maintenance or
improvement of groundwater arsenic concentration at the slag shoreline.
Asarco proposes a compliance point of surface water along the face of the post-RA slag
shoreline.
Remedial Action Objectives
The Proposed Plan modifies the earlier RAOs in the Upland ROD for the Site making them
overly broad and inappropriate. EPA's remedial action objectives (RAOs) for groundwater in
the Proposed Plan are as follows:
1. Prevent ingestion of or direct contact with groundwater containing contaminants.
2. Prevent discharge (to Commencement Bay) of groundwater that exceeds
applicable marine surface water quality standards or background concentrations
(if background concentrations are higher than the standards).
For comparison, the Upland ROD RAOs are:
1. Prevent ingestion of potable (Class IIB) groundwater ... containing contaminants
in concentrations above ARARs or above risk-based goals when ARARs are not
protective or not available.
2. Reduce discharge to Commencement Bay of contaminated waters containing
contaminants in concentrations above ARARs or risk-based goals when ARARs
are not protective or not available.
As written, Proposed Plan RAO #1 is neither achievable nor necessary. EPA has substituted
"groundwater" for "potable groundwater" and "groundwater containing contaminants" for
"groundwater ... containing concentrations above ARARs..." All groundwater, everywhere,
contains "contaminants" but that is not a problem for human health or aquatic life unless
concentrations are too high (i.e., above ARARs or risk-based goals). As written the RAO is
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so broad that it is nearly meaningless and gives no direction to the goals that are to be
achieved.
Compared to the Upland ROD RAOs, Proposed Plan RAO #2:
• substitutes "prevent discharge to Commencement Bay of groundwater" for
"reduce discharge of contaminated water"; and
• substitutes "background concentrations" for the phrase "risk-based goals when
ARARs are not protective or not available".
Prevention of discharge of groundwater from the Site is not technically possible. However,
the Preferred Alternative will reduce the discharge of groundwater from the Site to the extent
practicable and will reduce the discharge of contaminants to levels that are clearly protective
of human health and the environment.
Background concentrations are not appropriate substitutes for risk-based goals for arsenic
since Site-specific risk information and protective risk-based goals are available. The
Proposed Plan correctly points out that
"Neither the Maximum Contaminant Limits (MCLs) promulgated under the Federal
Clean Water Act nor the State of Washington Model Toxics Cleanup Act (MTCA)
groundwater cleanup levels are considered Applicable or Relevant and Appropriate
Requirements (ARARs) for the shallow groundwater system at the Facility. " page 15,
Proposed Plan
In this case, it is appropriate to use risk-based levels and EPA correctly notes that:
"Currently, the groundwater discharging to Commencement Bay will exceed human
health risk based levels for fish consumption (0.14 fig/L for arsenic) (National Toxics
Rule; CFR 40, § 131.36). However, past fish tissue sampling indicates low risk from
Facility contaminants even to people consuming large quantities of fish from the
Facility, "page 15, Proposed Plan
However, the RAO and RG for arsenic fail to acknowledge EPA's uncertainty in the
National Toxics Rule (NTR) fish consumption limit and fails to acknowledge EPA's Site-
specific data and risk assessment. The NTR does not reflect the current understanding of
arsenic health risks. EPA has been reviewing the NTR arsenic criteria for several years with
the intent to revise the criteria. EPA's risk assessment indicates that existing risk from fish
consumption is acceptable and will be lowered further by implementation of the Preferred
alternative.
CERCLA Section 121(d)(2)(B)(i) provides a standard for determining whether or not any
water quality criteria under the Clean Water Act is relevant and appropriate. In making this
determination, Section 121 directs that the Agency:
"... shall consider the designated or potential use of the surface or groundwater, the
environmental media affected, the purposes for which such criteria were developed,
and the latest information available."
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The existing human health criteria for arsenic in the NTR does not reflect the latest
information available and does not consider Commencement Bay, the environmental media
affected. EPA is currently in the process of revising the human health criteria for arsenic in
the NTR. Recent information on arsenic risks in Commencement Bay are available in EPA's
risk assessment entitled "EPA Ecological Risk Assessment and Seafood Consumption
Screening Risk Assessment Asarco Sediment Site - October 1996." Given the uncertainty in
the NTR arsenic level and the existence of more recent Site-specific data, Asarco believes
that the NTR arsenic level should not be an ARAR for the Site in accordance with CERCLA
Section 121 (d)(2)(B)(i). In establishing the RAO for arsenic in groundwater, EPA should
consider the latest information on the environmental media affected. The latest information
available is EPA's risk assessment on Commencement Bay. Asarco proposes that the RAO
be revised to include the use of risk-based limits for arsenic.
Remediation Goal for Arsenic in Groundwater
For current arsenic risks EPA's risk assessment (EPA, October 1996) concluded:
1. The potential for adverse non-cancer health effects associated with ingestion of
fish caught near the site is low (i.e. at or below the hazard quotient benchmark
value of 1.0).
2. For the reasonable maximally exposed individual, inorganic cancer risk estimates
are close to but not greater than the upper end of the risk management range
recommended in the NCP (1 x 10"6 to 1 x 10"4) at fish ingestion rates greater than
approximately 150 grams per day.
3. For the average case individual, inorganic cancer risk estimates are within or
below the NCP risk management range at all fish ingestion rates considered.
Or as summarized by EPA in the Proposed Plan:
"... past fish tissue sampling indicates low risk from Facility contaminants even to
people consuming large quantities offish from the Facility, "page 15, Proposed Plan
In light of Site-specific data regarding the low arsenic risk from seafood ingestion, Asarco
proposes that an appropriate RG for arsenic would be based on maintaining existing arsenic
concentrations in groundwater discharging to Commencement Bay. Since the Preferred
Alternative will result in a substantial decrease (to the extent practicable) in the amount of
groundwater flow to Commencement Bay, maintaining groundwater arsenic concentrations
would result in substantial decreases in the load (or mass) of arsenic discharged to
Commencement Bay. Therefore, the Proposed Remedy with Asarco's proposed RG would
result in further reduction to the maximum extent practicable of the already acceptable
arsenic risk.
Groundwater Compliance Point
The Proposed Plan does not specify a compliance point for groundwater discharging to
Commencement Bay. Asarco proposes that the compliance point for groundwater discharges
should be in the surface water as close as technically possible to the point or points where
ground water flows into the surface water. After remediation, the point on the Site that is "as
close as technically possible to the point or points where the ground water flows into the
surface water" will be surface water along the face of the stabilized and protected slag
008\1103\word\Asarco Resp.doc
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shoreline. This compliance point of surface water along the face of the post-RA slag
shoreline would protect the water resource at the point of possible human or aquatic life
exposure and would comply with MTCA.
Under Washington's Model Toxics Control Act (MTCA), groundwater compliance
monitoring points should be selected to be "as close as technically possible to the point or
points where the ground water flows into the surface water." (WAC 173-340-720(3)(b)(v)).
Furthermore, "At these sites [where the affected ground water flows into nearby surface
water], the department may approve a conditional point of compliance that is located within
the surface water as." (WAC 173-340-720(6)(d)). Presently, the point where groundwater
flows into surface water on the Site is the face of the slag shoreline. During Upland
remediation, the face of the slag shoreline will be armored to prevent erosion. After Upland
remediation is completed, the point where groundwater flows into surface water on the Site
will be the face of the armored shoreline. Therefore, the proposed groundwater compliance
point is surface water at the face of the post-RA shoreline.
Additional groundwater capture
The Proposed Plan delays a final decision on the need for additional groundwater controls
pending additional remedial design analysis. Asarco believes that the existing information
demonstrates that additional groundwater controls are not appropriate and that ongoing
evaluations during Remedial Design are unnecessary.
The hydrologic analyses of the feasibility of additional upgradient groundwater controls have
been completed and draft reports have been submitted to EPA. These analyses demonstrate
that additional groundwater controls would capture negligible amounts of additional
groundwater and contaminants. Capture and treatment would reduce some, but not all metal
concentrations in the captured groundwater and would eliminate the current reduction in
arsenic concentrations provided by natural attenuation on the Site. Therefore, little or no
environmental benefits would be realized by the additional groundwater capture. Costs
associated with constructing an interception system and the additional treatment costs would
be substantially and disproportionately expensive relative to the environmental benefit
received.
Treatment of Captured Groundwater
The Proposed Plan presumes that treatment of groundwater will be necessary. The Proposed
Plan should clearly state that treatment is not required unless treatment is necessary to meet
Remediation Goals. Moreover, it is important to note that:
• Design of the stormwater treatment system is an Upland Remedial Design task.
• Design of the stormwater treatment system is based on treating stormwater, not
groundwater.
• Design of the stormwater treatment system is ongoing.
Therefore, the Proposed Plan needs to be flexible regarding treatment of groundwater by the
yet to be designed stormwater treatment system. One area in which the Proposed Plan may
unduly constrain design of the surface water treatment system regards the treatment of
groundwater during baseflow (i.e. non-stormwater flow) periods. The Proposed Plan needs to
008\1103\word\Asarco Resp.doc
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allow the potential for bypass of captured groundwater from treatment during baseflow
periods if such bypass is consistent with stormwater treatment.
Specific Comments
Page 3, 5th bullet. This bullet states that Asarco will monitor the dredged area "...to ensure
that it is not becoming recontaminated." Asarco is responsible for recontamination, if any
that originates from the Site, but cannot ensure that the Yacht Basin will not become
recontaminated from marina activities.
Page 4, 3rd bullet. The Refinement of the Proposed Remedy Report was revised and
submitted to EPA on January 5, 1999. This document should be referenced instead of the
August 1999 draft.
Page 4, document list. The Copper in Nearshore Marine Water Technical Memorandum
submitted to EPA on June 23, 1999 should be included in the list of documents providing
additional detailed information.
Page 6, first para. Sentence states "The shallow aquifer system beneath the Facility is
largely recharged by lateral flow of groundwater from the southwest (Ruston area) and
infiltration of precipitation and surface water run-on. "
It would be more accurate to say "The shallow aquifer system beneath the Facility is largely
recharged by infiltration of precipitation and surface water run-on and to a minor extent by
lateral flow of groundwater from the southwest (Ruston area)
Pg. 9, 3rd full para. This paragraph compares site tissue concentrations to reference tissue
concentrations and ignored the sections of the Phase 1 Data Report that showed "...the site
station tissue chemistry was found to be indistinguishable from the reference station tissue
chemistry in all cases (see Table 8-3)." In other words, the differences were not statistically
significant. Further, it is not appropriate to state that tissue concentrations are elevated
without providing any risk context. Anyone that only gets this far reading the document may
not learn that these tissue concentrations are acceptable using EPA's risk criteria, as stated
later in the Proposed Plan.
Page 9, last full para. This paragraph seems to state that copper exceeds the marine chronic
criteria (MCC) at all locations in Commencement Bay near the Site. This is not true. The best
data available to Asarco and EPA indicates that copper concentrations currently exceed the
MCC at about half of the sampling locations along the shoreline and only in very close
proximity to the slag shoreline. At most locations, seawater a few feet away from the slag
meets all aquatic life criteria for copper and all other metals.
In conjunction with the Asarco Sediment/Groundwater Task Force (ASGTF) Asarco
conducted two rounds of special seawater monitoring in 1999 to determine copper
concentrations in seawater near the Site. This seawater monitoring employed ultraclean
sampling and analytical techniques and yielded analytical sensitivities and accuracies several
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orders of magnitude better than techniques previously available. Results of this monitoring
were submitted to EPA in a June 1999 Draft Technical Memorandum and in a November 16,
1999 data transmittal. The ultraclean monitoring data demonstrates that copper
concentrations do not exceed criteria in all samples; only samples collected near the shoreline
in some areas.
Page 13, The First Bullet is incorrect regarding Task Force findings related to arsenic. The
Task Force found (see page 6-5 of the March 1999 ASGTF Group 5 Technical
Memorandum) that groundwater discharges currently cause water column concentrations to
exceed only the copper chronic aquatic life criterion. Current water column concentrations of
arsenic and other metals are better than the chronic aquatic life criterion.
Page 14, 1st para. What does "nonminimally impacted" mean?
Page 15, Remediation Goals. At a minimum it would seem appropriate for EPA to
acknowledge that the NTR arsenic criteria is under revision. It might also be appropriate to
establish that if the arsenic RG can not be met, then the revised arsenic criteria would be
considered in determining the need for additional groundwater controls/remediation.
Page 16, 2nd para. Deep groundwater does not presently exceed MCLs or MTCA standards
for any parameters except possibly arsenic (see Summary and Interpretation of 1994, 1995,
1996, 1997 and 1998 Post-RI Long-Term Monitoring Results (Hydrometrics, 1999) and
Table 4-3 in Summary and Interpretation of Production Well Abandonment Action-Specific
Monitoring Results (Hydrometrics, June 1997).
Page 20, Table 7-3. The note for alternative S-2D states: "As a contingency, if all the
contaminated material cannot be removed from the Yacht Basin, dredging in the Basin
followed by placement of clean material may occur." EPA should acknowledge that slag will
remain in the Yacht Basin following dredging and that this material, though it may exceed
CSLs, has been shown to not exhibit contaminant effects at other areas of the Site. It would
not be possible to remove all the slag exceeding CSLs from the basin without removing the
entire breakwater peninsula, and dredging at the base of the peninsula will need to be
designed so that it does not destabilize steep slopes. Placement of clean material over the slag
will not be necessary because the metals in slag are bound in a rock-like form and are not
necessarily available to the benthic community.
Page 23, last para. The Plan states "Modeling performed by the Task Force indicates that
state and federal laws applicable to protection of marine water quality may not be currently
achieved within a few feet of the shoreline for all metals. " Although model results did
indicate some metal concentrations above marine chronic criteria, the Task Force placed
more emphasis on empirical data rather than model predictions in concluding impacts from
groundwater. The Task Force concluded that with the sole exception of copper, groundwater
discharge currently does not cause metal concentrations to be higher than marine chronic
criteria (see page 6-5 of the March 1999 ASGTF Group 5 Technical Memorandum).
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Page 25, 2nd para. States "The in situ treatment and seawater injection treatment
alternatives would promote chemical precipitation (i.e., "settling out") of arsenic from
groundwater, thereby reducing the arsenic load reaching Commencement Bay." Based on
the Asarco Sediment/Groundwater Task Force evaluations, the effectiveness of in situ
treatment is uncertain given that seawater already oxidizes and removes arsenic to the extent
practical, with the exception of the Southeast Plant area.
Page 28, bottom of page. It states "Additional groundwater interception is being considered
at the Facility, and may also be considered by EPA at a later date. The need for additional
groundwater interception would be based on the results of ongoing groundwater sampling
Earlier in the Proposed Plan (3rd paragraph, pg. 27) it is stated that additional diversions are
disproportionately expensive and would only be considered if cleanup goals could not be
met. Asarco agrees that additional interception is disproportionately expensive and believes
that additional interception should only be considered if cleanup goals are not met.
rd
Page 29, 3 para. It states "At a minimum, monitoring wells at the downgradient perimeter
of the Facility (along the shoreline) will be monitored, including wells near source areas. "
Rather than "wells near source areas ", it would be better to say, "wells near source areas if,
and to the extent compatible with, protection and maintenance of the cap."
It further states "/« addition, should the groundwater indicate high concentrations of metals,
contingency actions, such as additional groundwater diversions, may be considered." What
is meant by high metal concentrations? Above cleanup goals? Where? It is expected that
concentrations will remain above cleanup goals in and near source areas but this occurrence
alone should not trigger additional diversions. Given EPA's broad authority under the five
year review provisions of the Upland ROD, this last sentence is unnecessary and should be
deleted. If the sentence is retained, then EPA should specify the trigger criteria of "high
concentrations of metals". Asarco believes appropriate trigger criteria would be remedial
action objectives and remediation goals (including Asarco's proposed changes) at a
compliance point located in surface water along the armored slag shoreline.
008\1103\vvord\Asarco Resp.doc
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received
Enviroi
mar I 9 2°00
omental Cleanup Office
WASHINGTON STATE DEPARTMENT OF
Natural Resources
JENNIFER M. BELCHER
Commissioner of Public Lands
March 27, 2000
Mr. Lee Marshall, Project Manager
Office of Environmental Cleanup
US EPA Region 10
1200 Sixth Avenue, MS ECL-111
Seattle, WA 98101
Subject: Comments on the Proposed Plan. Asarco Sediments/Groundwater Operable
Unit. Ruston and Tacoma, Washington, January 2000
Dear Mr. Marshall,
Enclosed please find comments regarding the Asarco Sediments and Groundwater
Proposed Plan. The comments are provided on behalf of the Washington State
Department of Natural Resources (DNR) and are based on a summary review of the
Proposed Plan document. We appreciate the opportunity to provide input and would like
to thank the Environmental Protection Agency (EPA) for extending the comment
deadline in response to our letter dated February 4, 2000. It is our understanding that the
comments will be considered by EPA in the determination of a cleanup plan for the site.
As trustee and land manager for public aquatic lands at the site, we rely on clear standards
for use of public aquatic lands - standards that are defined in state laws and the state
Constitution, in long-standing policies and strategies for implementing these laws, and in
guidance developed to ensure we effectively and permanently solve current
contamination and avoid future contamination.
Based on the information provided in the Proposed Plan, we believe that additional
evaluation is necessary to ensure that we can meet the management standards for public
aquatic lands at this site and in the bay. Specifically, we are concerned about restoration
and sustainability of natural resources at the site as a component of the overall function
and productivity of Commencement Bay. We are also concerned about appropriate short-
and long-term land use, source control, and risk and responsibility management. The
following discussion identifies a number of issues that we request receive further
consideration.
1111 WASHINGTON ST SE I PO BOX 47000 I OLYMPIA, WA 98504-7000
FAX: (360) 902-1775 I TTY: (360) 902-1125 I TEL: (360) 902-1000
Equal Opportunity/Affirmative Action Employer
RECYCLED PAPER
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Mr. Lee Marshall
Page 2
March 27, 2000
Endangered Species Act (ESA)
We anticipated that the extension to the comment period would provide the opportunity
to review the Proposed Plan in the context of the Commencement Bay Biological
Assessment (BA). We view the BA as critical to decision-making at all scales in the bay,
including site-specific cleanup actions. Without consideration of the BA, we do not
believe that our common goal of achieving cleanup in a broader ecosystem management
context can be ensured. We also cannot evaluate the adequacy of the proposed site-
specific remedial action in achieving ESA compliance without review by and discussion
with EPA and National Marine Fisheries Service of the BA and the biological opinion.
Until this information and analysis is available, we remain concerned that the effects of
the proposed remedial action on critical habitats for chinook salmon are not resolved at
either a site or baywide scale.
For example, we are concerned with the lack of information and guidance on the
functional linkages between deep water (>-10 MLLW) epibenthic habitats and the
foodweb for young-of-year and immature resident chinook salmon. Recent studies of the
polychlorinated biphenyls body burdens for Puget Sound chinook and herring stocks
indicate an exposure pathway link between the benthic community and the pelagic
foodwebs of these species. This information argues for a very conservative approach to
remediating chemicals of concern for bioaccumulation, such as arsenic and mercury.
We are also concerned that the proposal does not restore the healthy nearshore habitats,
both as salmonid migration corridors and as intertidal feeding areas, that once existed at
the site. In addition, we believe that decisions regarding cleanup objectives arc based on
incomplete information. We encourage incorporation of the latest information from the
federal services - particularly results of current NMFS efforts - on cleanup standards that
are protective of trust resources.
Available information suggests that numerous individuals from the White River chinook
stock are expected to rear nearshore at the Asarco site for extended periods. The
proposed plan does not provide sufficient information to determine the degree to which
chinook salmon will be restored and protected. We encourage EPA to more actively
integrate the numerous cleanup decisions necessary throughout Commencement Bay
within the context of the Commencement Bay BA and biological opinion. We are
interested in working with EPA on a management plan for the entire bay that defines both
site-specific and baywide implementation actions, with net gain in habitat area and
function being one of the primary plan objectives.
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Mr. Lee Marshall
Page 3
March 27, 2000
Land Use
The current proposal includes the permanent capping of contaminated sediments in place.
Siting such permanent caps within the City of Tacoma Harbor Area - as the proposal
currently does - is problematic in that the caps may be inconsistent with constitutional,
statutory and regulatory directives.
The main issues are:
• Capping as a mechanism for contaminated sediment storage is a non water-
dependent use. Non water-dependent uses in harbor areas are considered interim
uses and can only be allowed if defined criteria are met (e.g., compatibility and
exceptional circumstance analyses and other factors, Washington Administrative
Code (WAC) 332-30-137);
• Institutional controls (i.e., Regulated Navigation Area) likely necessary to
maintain the integrity of the capped areas will limit commerce and navigation in a
Harbor Area. However, Harbor Areas are reserved for commerce and navigation
in the Washington State Constitution; and
• Caps displace navigation and increase present navigational hazards.
In addition, some of the proposed cap appears to extend beyond the outer harbor line.
This is especially problematic because Article XV Section 1 of the Washington State
Constitution establishes that "the state shall never give, sell, or lease to any private
person, corporation, or association any rights whatever in the waters beyond such harbor
lines."
If the proposed caps are authorized, the City of Tacoma's Harbor Area will have to be
adjusted, a time-consuming process subject to rules detailed in WAC 332-30-116. A
Harbor Area relocation should maintain or enhance the type and amount of harbor area
needed to meet long-term needs of water dependent commerce. The relocation should
also maintain adequate space for navigation beyond the outer harbor line. After these
findings are made, there are other issues to be considered (see WAC 332-30-116(2)).
We have identified to EPA the value of the Asarco area as an important functional
component to the overall Harbor Area in Commencement Bay. We continue to
encourage EPA to define a plan that recognizes this important land use role and that
allows a balance between commerce/navigation and habitat functional needs. The
cleanup plan should not impact the existing deep draft capability at the site or lessen the
current and future capacity for structures associated with navigation and commerce.
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Mr. Lee Marshall
Page 4
March 27, 2000
Permanence of Proposed Remedy
The proposed plan does not define the design life for the remedy. It is uncertain how long
monitoring will occur, under what conditions monitoring will be enhanced or curtailed,
and what will trigger contingency actions now and in the future. These and other
concerns lead to uncertainty regarding the permanence of the remedy and to questions
regarding how exhaustively more permanent solutions were explored.
For example, the proposal to cap the north nearshore unit is not supported by the
information and analysis. The costs shown demonstrate that dredging and upland
disposal, a more permanent remedy, is less expensive. Costs associated with mitigation
for habitat impacts due to cap design, as well as a number of additional costs - including
potential compensation for use of public aquatic lands - not included in the existing
analysis, will increase the costs associated with the capping alternative. We therefore do
not support capping of this unit.
We also believe that permanent solutions such as treatment are viable. Vendors are
providing treatment rates of around $29 per cubic yard. We encourage EPA to further
evaluate treatment as part of the decision-making process.
For public aquatic lands, the state laws, the state Constitution, and the existing policies,
strategies, and guidance for implementing these laws do not support the use of public
aquatic lands for permanent storage of contaminated material. If contamination is to be
temporarily stored on public aquatic lands, the worst of the contamination must be
removed for treatment or upland disposal, and the remaining storage site must be
designed to allow future removal for treatment or upland disposal once technology makes
it feasible to do so. Neither the alternatives analysis nor the resulting proposal to cap
recognizes or incorporates these standards for use of public aquatic lands.
Source Control
The proposal for the sediments unit does not adequately provide for long-term isolation of
materials. For example, the porous slag slopes and incomplete armoring will result in
continued release of fine-grained slag particulates to the nearshore sediments. More
innovative alternatives to reduce the slopes to allow more effective armoring or to isolate
the peninsula in some other way need to be more thoroughly analyzed. The benefits and
total costs (including on-going source control, long-term operation and maintenance, and
contingency actions) associated with all potential alternatives need to be fully evaluated
in order to make well-informed decisions.
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Mr. Lee Marshall
Page 5
March 27, 2000
We strongly support alternatives to actively remove and treat contaminated groundwater,
and we encourage a commitment to long-term, intensive monitoring to determine
effectiveness of the remedy. We also encourage removal of any leaking, unused and/or
abandoned pipes and any other debris or unnecessary structures along the shoreline.
Finally, we would like to discuss the potential reuse of the treated groundwater as a
resource for restoration of a stream delta estuary. Such a delta existed on-site prior to
development. The value of these small estuaries as nodes of productivity is becoming
more widely recognized. Salmonid species such as chinook, chum, and cutthroat have
been documented to preferentially target these areas in their utilization of nearshore
corridors. The potential for creation of a stream delta estuary appears to exist on the
southeast portion of the site. Integration of planning for such a project with the remedial
and damage assessment actions may provide opportunities for an improved, less
expensive, more comprehensive project.
Natural Resource Damages
The facility's operations have filled and/or degraded a substantial acreage of aquatic
lands. The values of the public aquatic lands for a broad range of functions and services
are damaged. The proposed remedy does not restore those values, and Asarco has not
proposed to compensate the State of Washington as a natural resource trustee for past and
on-going losses. We will seek natural resource damages for functions and services that
are not restored in order to compensate the citizens' natural resource trust values.
The extent of damages will be highly-dependent on the degree to which the functions of
aquatic lands have been and will continue to be injured by slag deposition/deposits,
groundwater, runoff, point discharges, and other releases of injurious contaminants. We
encourage the resolution of natural resource damages claims in conjunction with the
remedial action processes at the site.
Text-Specific Comments
• (Section 5.2) It is unclear how healthy biological communities are being defined.
How was this determined? Diversity, abundance, both?
• (Section 6.1) What happens in the future if and when background concentrations
and laboratory detection limits drop? Will cleanup goals track these drops, if they
occur, until it reaches the National Toxics Rule standard of 0.14 (j.g/1 for arsenic.
Likewise for copper.
(Section 7) What is the term of the OMMP?
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Mr. Lee Marshall
Page 6
March 27, 2000
(Table 7.2 and 7.3) Alternative S-l E: Dredge and Upland Disposal has a present
worth cost of $26.2 million for 88,000 cy. This is $298/cy. Alternative S-2D:
Dredging and Upland Disposal has a present worth cost of $3.6 million for 55,000
cy of Yacht Basin sediment. This is $65/cy. Why is one over 4.5 times more than
the other?
• (Section 8.1) Do you understand why fish tissue remained below risk thresholds
even though groundwater exceeds human health risk based levels for fish
consumption? If not, how can you be sure that the environmental conditions
which allow this to happen will remain constant?
• (Section 8.1) Were the full range of potential organisms considered when
determining the thickness of cap necessary to prevent recontamination due to
bioturbation?
• (Section 8.2) The plan should require that institutional controls, maintenance and
monitoring results be shared and coordinated with DNR.
• (Section 8.6) Since the following sentence claims that pump and treat is reliable
and available, by "difficult" do you mean costly?
• (Section 8.7) The sentence "For all sediment areas, upland disposal is less costly
than nearshore confinement" is not consistent with Table 7.2.
• (Section 9.1.1) What will be the final quality of treated groundwater?
(Section 9.2.1) The likely static and dynamic slope stability risks indicate the need
for a more permanent solution.
• (Section 9.2.4) What is the contingency for heavy erosion of the cap?
We appreciate the opportunity to provide input to EPA. We also appreciate EPA's effort
to address issues. In particular, we applaud the recent discussions with local citizens
about their concerns, many of which we share. We look forward to active involvement
with the interested parties to resolve issues as the process moves forward. If you have
any questions or concerns, please feel free to contact me at 360-902-1148,
chuck.turley@wadnr.gov or Amy Kurtenbach at 360-902-1029,
amv.kurtciibach@wadnr.gov.
Sincerely,
Charles W. Turley
Assistant Division Manager
Aquatic Resources Division
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Mr. Lee Marshall
Page 7
March 27, 2000
c: Maria Victoria Peeler, Division Manager, DNR Aquatics
Mark Mauren, ADM, DNR Aquatics
Amy Kurtenbach, DNR Aquatics
Tammy Allen, DNR Aquatics
Kathy Marshall, DNR SPS Region
Bill Graeber, DNR Aquatics
Lee Stilson, DNR Aquatics
Tim Goodman, DNR Aquatics
Michelle Wilcox, Ecology, TCP
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917 Pacific Avenue
Suite 406
Tacomi. WA 98402
Phone (253) 383-2429
Fax (253) 383-2446
chb@wa.net
Board of Directors
Mary Brown
Jeff Daniel
Scott Hansen
Kristi Lvnctt
Lee Roussel
Robert Stivers
Shcri Tonn
Allen Zulauf
A tax-exempt
nonprofit organization with
501(c)(3) status
CHB
RECEIVED
MAR Z 9 2000
Environment/ Cleanup Office
CITIZENS FOR A HEALTHY BAY
March 27, 2000
Mr. Lee Marshall, Project Manager
US EPA Region 10
1200 Sixth Avenue s
MS/ECL-111 ......
,Seattle, WA 98101
marshall.lee@epamail.epa.gov
Re: Former Asarco Smelter Facility
Sediment and Groundwater Remediation
Ruston/North Tacoma, Washington
Dear Mr. Marshall:
On behalf of Citizens for a Healthy Bay (CHB), an organization representing 850 members of the
Tacoma and Greater Commencement Bay community, thank you for the opportunity to comment
on the proposed remedial plan for Asarco Smelter site groundwater and sediments. Except as
discussed below, CHB generally agrees with the remedial actions proposed for site sediments and
groundwater.
Of greatest concern is that EPA defer to and enforce all Washington State cleanup standards for
groundwater and sediments. As was recently proved in the findings for Asarco at the Asarco
Everett facility, failure to enforce Washington State standards on one site can have adverse
impacts to another site cleanup. As Asarco is a PRP for another Commencement Bay Superfund
sediment cleanup action in the Hylebos Waterway, it is imperative that uniform cleanup
standards be employed throughout the entire Commencement Bay cleanup area.
5.1 Human Health Screening Risk Assessment
Sfriimi»nts: In determining human health risks associated with eating fish caught within the
site, the low end range (1 gram per day of fish) was selected to represent the consumption of an
infrequent sports fisherperson who might eat fish from the waters off the facility a few times each
year. The greater Commencement Bay area hosts a number of ethnic communities who routinely
fish for subsistence. Because of easy access, the waters along Ruston Way/Asarco/Point Defiance
are a popular fishing spot for members of these communities. We believe that the assumption of 1
gram per day of fish does not consider the subsistence harvest practiced by members of these
communities and needs to be increased accordingly.
Printed on non-secondarily
bleached recycled paper with
soy based ink
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March 27, 2000
Mr. Lee Marshall
Page Two
5.2 Ecological Risk Assessment
Sediment:
Non-Impacted/Minimally Impacted Stations
Stations that have chemical concentrations greater than the state standards must be cleaned up to
meet Washington State standards. Additionally, those areas with minor biological CSL
exceedances must be remediated as well.
Moderately Impacted Stations
Stations falling within this category need to be remediated to meet Washington State cleanup
standards.
6.1 Groundwater Cleanup Objectives
Background contamination levels for copper in the remedial area are held to be 40 ug/L and a
question is raised as to whether groundwater cleanup levels of 3.1 ug/L can be met. However, no
mention is made as to what the background levels for copper in groundwater are for the
Commencement Bay area outside of the Asarco site. Presumably, the higher copper background
contaminant level is directly attributable to past smelter operations, and therefore subject to
remedial action to correct the problem.
6.2 Sediment Cleanup Objectives
EPA's stated cleanup objective for sediments is to restore and preserve aquatic habitats by
limiting or preventing the exposure of environmental receptors to sediments with contaminant
above Washington State Sediment Management Standards.
7.1 Groundwater
We agree with the stated preferred alternative GW-B involving intercepting and treating site
groundwater prior to discharging into Commencement Bay. We are concerned that the remedy be
scaled to handle large magnitude storm events and associated increases to groundwater.
Also, use of an on-site cap to limit infiltration of precipitation into the soil will increase the
amount of stormwater runoff and contaminants commonly associated with stormwater runoff.
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March 27, 2000
Mr. Lee Marshall
Page Three
How will recontamination of the sediments by toxins such as PAHs, BEPs, fertilizers, herbicides,
insecticides, etc. be avoided? We do not wish to see one set of problems exchanged for another.
7.2 Sediment
In addition to the remedial alternatives presented in the proposed cleanup plan, additional actions
are required in the Non-Impacted/Minimally Impacted Stations and Moderately Impacted
Stations to ensure that these stations are remediated to meet all State of Washington Criteria, (see
5.2 above)
9.2.4 Long-term Monitoring
Components of the long-term remedial monitoring plan must include action plans for
earthquakes, high-intensity storm events, severe tide/wind storms, etc.
Citizens for a Healthy Bay urges you to consider that private citizens, aquatic communities and
the improved health of Commencement Bay are the largest stakeholders in the cleanup and
disposal of contaminated sediments and groundwater at the former Asarco Smelter site. As a
citizen-based representative of that community, Citizens for a Healthy Bay is concerned about the
decisions EPA will make regarding remediation at the Asarco site. We urge the Environmental
Protection Agency to make decisions that will positively aflect the primary stakeholders in the
cleanup of Asarco sediments and groundwater.
We appreciate your attention to our concerns regarding this document.
Leslie Ann Rose
Senior Policy Analyst
Citizens for a Healthy Bay
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RECEIVED
Lee Marshall
EPA Project Manager
1200 Sixth Avenue
MS/ECL-111
Seattle, WA. 98101
February 17, 2000
Dear Mr. Marshall:
As a long-time resident of North Tacoma, I would like to take this opportunity to
comment on the EPA cleanup of the Asarco smelter. I would like to voice my concerns about
the long- term effectiveness of the proposed disposal alternatives. I can not see how capping
contaminated sediments on-site with 1 meter of clean material represents a safe and reliable
solution. Humans have been burying garbage for thousands of years, surely we can do better
than this by now? I would like to encourage the EPA to support the development and use of
improved treatment methods. I believe the government has an obligation to the future health
and well being of humans and the environment to forward progressive solutions. In addition,
1 am concerned about the storage of contaminated sediments so near the water. Earthquakes
and slides could yield potentially disastrous results. Furthermore, there is the corrosive,
erosive capacity of the salt air and water to consider. Hopefully, the EPA will continue to re-
evaluate conditions at the site and apply improved treatment measures as they become
available. Thank you for your thoughtful consideration.
Sincerely,
Valerie Anderson
4121 North Gove Street
Tacoma, WA. 98407
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FORMAL COMMENT PERIOD
JANUARY 26 THROUGH FEBRUARY 24, 2000
FOR
Asarco Sediments and Groundwater Proposed Plan
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Wayne C.R. Taylor;
8101 -83rd Avenue STV., //J-38
Lakewood, WA 98498-6040
(253)-984-7423
wcrt@hotmai 1 .com .. ../
^ 13 2000
Thu;09.^ar.^00C
EPA Project Manager
1200-Sixth Avenue ¦
Seattle, WA 98101
ATTN: Lee Marshall
I recfehtiy saw an iteto in the Tacotfia News tribune concerning the cleanup of the
old ASARCO site in ftuston. I would like to add written comments toward the" ~
process of cleaning up the. wastes. ..
My standpoint, you itiust understand, comes from a' m'etallurgical engineer who"
had an opportunity to tour the ASARCO smelter while a young college student. '
It is unfortunate to the community and the area as a whole that so much toxic
substances were released into the environment in the name of progress and the
almighty dollar. It should also be remembered that the plant offered employment
to numerous workers during its lifetime. It was a mbnument to the ingenuity
of metallurgists while how becoming a bane to those of us in the profession.
It is demoralizing to think that the metals industry has had to cope with
changes that sometimes make my training obselete. ..
Oust as a passing thought; " there"'fire plans' to remove and store in a landfill , '•
the contaminated soils around the Ruston plant. And the Seattle-Taocma airport
is looking for fill for their third proposed runway. Abra-cadabra! Why not
use this soil for their fill and kill two birds with one stone?.. I had heard
some statistics about the amount of fill needed for the S£A-TAC airport and
the time needed to complete their plans, much to the consternation of the local
residents. •
> '• Vf.
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Another thought; why not sell, for refining, the waste "products from the ASARCO
plant? It used to be that tailings piles from older mines would be reprocessed
again and again to remove the smallest traces of valuable metals. Arsenic V
still has used in rodenticides. Lead is used in storage batteries. Cadmium v
is used in low-melting point alloys. What other treasures could be gleaned
from all the waste? , . „ ¦ , . ; /
The' EPA plan to coVer ihe" site with nbn-p^rmeabi'e ffiatefial doe¥rnot" take into' .
account one thing; water seeping UP through the covering layer. This is something
that must be considered in our wet Washington weather. • "«¦¦¦
' • ;v ¦ . .. . \ 's- ' J
Men have torn down mountain's to get 'to'preciou^ metals Mr V long time. If . j:r
the material at Ruston is offending, why not dig out a big hole and put it '
back into those torn-down mountains? .f. '
•• ¦. iv' i •'
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: " - «'¦
Thes§ are riiy thoughts and suggestions cbncefnihg the "treatment of the wastesite -
at ASARCO's Ruston plant. 1 hope they are doing a better job of not polluting • ;..
in their new location in the southwestern USA.- It was a kick in the butt to *
see them leave town. That was one less place I could have sought gainful employment *
from. .
- 'rj' ¦' i- ¦- " .•. -v' . ;.-v! ^
Thank' you for the Opportunity to "continent on ycSijr proposals!
Sincerely,
cyC I f
Wayne C.R. Taylor ^ ^
former President; Metalchemy, Inc.
"The Metal chemist"
r ' ^ '' '
••' V-:i '
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