Lower Duwamish Waterway (cleanup
jPk United States
Environmental Protection
M % Agency
DEPARTMENT OF
ECOLOGY
State of Washington
Fact Sheet
Planning for Cleanup
Learn about the draft cleanup alternatives for the Lower
Duwamish Waterway, and how you can have a say in how
cleanup moves forward!
Lower Duwamish Waterway - Resources and Challenges
The U.S. Environmental Protection Agency
(EPA) and the Washington State Department
of Ecology (Ecology) have released a draft study
of cleanup alternatives for the Lower Duwamish
Waterway. We are asking for public input on a
wide range of options to reduce toxic pollutants
in the waterway. Past and present activities have
left a legacy of chemical pollution in the waterway
and in the sediment (mud at the bottom). This
pollution comes from many sources, including
industries along the waterway and stormwater
runoff from upland activities, streets, and roads.
The pollutants we are most concerned about
include polychlorinated biphenyls (PC-Bs),
dioxins and furans, carcinogenic polycyclic
aromatic hydrocarbons (cPAHs), arsenic, and
other chemicals. .Many of these chemicals stay
in the environment for a long time and have
built up to unhealthy levels in the waterway and
in the fish and shellfish that live there all year
long. Because of these health risks to people and
animals exposed to contaminated sediments, in
2001-2002, EPA and Ecology listed the 5-mile,
441-acre Lower Duwamish Waterway under the
federal Superfund law and Washington's Model
Toxics Control Act.
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LDW Study Area
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What's Wrong with the Lower Duwamish Waterway?
Health Risks to People and Animals
Most health risks to people come from eating resident
fish, crabs, and clams from the waterway; state and local
health departments warn against eating crabs, shellfish,
or bottom-feeding fish from the lower waterway.
Salmon, which move quickly through the waterway, are
less affected by site contamination.
Repeated direct contact with contaminated sediments
in some waterway areas may pose health risks, though
it is safe today to play in most public areas, such as
Duwamish Waterway Park.
Chemicals in some areas affect animals that live in the
mud such as worms and clams and pose risk for river
otters and other wildlife.
Future Vision for the Duwamish
Waterway
A healthier environment for the fish and other animals
that live in the waterway, and the people who live, work,
and play here.
Reduced risk for people eating seafood from the Lower
Duwamish.
Cleanup that supports community hopes for restoring
habitat, adding public access, encouraging recreation,
and retaining economic vitality.
We will all benefit from a cleaner waterway in the future
that continues to support navigation, industry, and
commerce, including 100,000 jobs in the 8 square miles
around the waterway.
A Lot is at Stake
Cleanup of the waterway will take time, money,
and patience the options include tradeoffs to spur
discussion before a specific cleanup plan is proposed.
Your voice, as a member of the community and this
region, is critical to help make decisions about the
Duwamish cleanup.
It's time to learn more, ask questions, provide your ideas
now, and prepare to review the proposed cleanup plan in
early 2012.
Things to think about: What do you think are the
most important considerations for evaluating cleanup
alternatives? How would you like to be able to use the
river in the future? What are your concerns about how
the cleanup might impact you or your community?
Things to Watch
Controlling upland pollution sources - Reducing
the pollution entering the waterway is critical to avoid
new pollution and to help keep cleaned-up areas from
becoming polluted again. Runoff from polluted upland
sites and everyday urban activities continues to impact
the waterway. Ecology has completed Source Control
Action Plans for 15 of 24 basins that drain to the
waterway These plans call for more than 450 actions
to reduce sources of pollution to the waterway. Many
of these actions are under way, including 13 cleanup
orders to investigate and clean up contaminated facilities
nearby, and working to reduce sources from municipal,
industrial, and sewer/stormwater outfalls.
Early action areas - Several hot spot areas will be
cleaned up first. Two early cleanups were conducted;
three more are in progress (see map on opposite page).
Cleaning up early action areas first will reduce PCB
contamination by about half.
Cleanup of the rest of the waterway - That's what
you are reading about here - the draft Feasibility Study
for cleaning up the rest of the waterway. Options for
cleanup and how they measure up - that's the big story.
2 | Lower Duwamish Waterway Cleanup
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Where is the Pollution - and How Bad is It?
Chemicals of concern include: Dioxins/furans
Polychlorinated biphenyls (PCBs) * Arsenic and other metals
3 | Lower Duwamish Waterway Cleanup
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Cleaning Up the Duwamish Waterway - How Do We Do It?
The goal of cleanup is to reduce the pollution in the waterway to levels that will
protect people and animals. The draft Feasibility Study outlines the different
methods available for cleanup, and describes a wide range of ways to combine
those methods into cleanup alternatives. It evaluates these alternatives against
regulatory requirements and compares predictions of how Well they would work,
their side effects, how long they would take,, and how much they would cost.
The waterway is big, complex, and dynamic. On average, more than 100,000
metric tons of new sediment comes downstream from the Green River and settles
in the waterway each year. This is enough to fill 12,000 dump trucks. Some
areas of polluted sediment in the waterway are already being covered up with the
cleaner sediment coming from upstream. Tidal influence from Elliott Bay is also
significant, The waterway and surrounding land are used in many different ways,
creating different impacts. With this complexity, we will need a range of methods
to solve the problem.
Methods for Managing Contaminated Sediments
Several cleanup methods can be used to clean up contaminated sediments in the
waterway. Some methods rely mostly on construction, such as dredging and
capping. Others rely more on the natural flow of cleaner sediments from upriver.
Removal
Containment
Natural Recovery
Treatment
Disposal
Engineered Caps
Enhanced Natural
Recovery
Monitored Natural
Recovery
Decreasing Total Cost
Increasing Removal or Containment
Removal
Physical removal or dredging of contaminated
sediments. Options to deal with the dredged
material after removal include:
- Treatment and disposal
- On-site (e.g., in a contained in-water
disposal facility) or off-site disposal (e.g., in
a permitted landfill)
4 | Lower Duwamish Waterway Cleanup
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Containment
Containment or capping (covering with clean
material) of contaminated sediments, typically
using layers of sand, gravel, and rock designed to
contain and isolate the pollution
Dredged Area;
Barge-Mounted
Excavator
Placement
Contaminated
Sediment
Contaminated
Sediment
Capping
Natural Recovery
Enhanced natural recovery using a thin layer of
sand to cover the pollution and speed up natural
recovery
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Enhanced Natural Recovery (ENR)
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Monitored natural recovery, which relies on the
natural flow of cleaner sediments from upriver
to cover contaminated sediments in the lower
waterway, and includes long-term monitoring
Monitored Natural Recovery (MNR)
Tidal Current Flow
i MNR Monitoring
J Net Burial
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RECENT SEDIMENT
Buried Contaminants
Newly Deposited
Green River Sediment
NATIVE SEDIMENT
Monitoring and Adaptive Management
Monitoring to track pollution levels in the sediments, water, and fish and shellfish before, during, and after construction. More
cleanup will be required if monitoring shows pollutant levels are not decreasing as expected.
Other actions (also called Institutional Controls) are needed to reduce people's exposure to remaining contamination.
These include: health advisories to limit eating resident seafood from the waterway and restrictions on activities such as digging
or anchoring in specified areas.
5 | Lower Duwamish Waterway Cleanup
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Consider the Cleanup Alternatives
The purpose of the draft Feasibility Study is to examine a range of cleanup approaches. Each alternative uses a
mix of methods to achieve cleanup goals. The higher numbered alternatives require active cleanup (e.g., dredging
or capping) over more of the river, using lower chemical concentrations as trigger levels for cleanup. The lower
numbered alternatives place more emphasis on monitored natural recovery. The "removal emphasis" alternatives use
mostly dredging, while the "combined technologies" alternatives use less dredging, and more capping and enhanced
natural recovery. Here is how you can get familiar with the alternatives. You can find much more detail about all of
these alternatives in the draft Feasibility Study online at www.ldwg.org.
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How Do They Compare?
The alternatives evaluated in the draft
Feasibility Study were evaluated using
both federal (EPA) and state (Ecology)
criteria. Two threshold criteria must be
met first: 1) protect human health and
the environment, 2) comply with federal
and state environmental laws, and 3)
regulations and monitor compliance with
these standards. Then the evaluation
looks at:
Long-term effectiveness and
permanence
Reducing toxicity, mobility, or volume
through treatment
Short-term effectiveness
Ability to be implemented
Cost
Key Things to Think About
Alternatives 2 through 6 include varying amounts and types of
construction. All are predicted to reduce contamination by up to
90% in the long term, and reach similar levels of risk reduction,
but with different time frames.
Alternatives with more dredging will give more certainty in
the long-term, but with more short-term impacts (disturbance,
emissions, traffic, etc.); they take longer and cost more.
Alternatives with more capping and enhanced natural recovery
have less short-term impacts and cost, but increase the need for
long-term management and monitoring.
Alternatives with more monitored natural recovery have the
lowest short-term impacts and cost, but with the most uncertainty,
and the greatest need for long-term management and monitoring.
Treatment of dredged sediments could reduce the volume of
sediment needing disposal but it increases cost. Though evaluated
with one alternative, it could be used with others.
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Alternatives
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7 | Lower Duwamish Waterway Cleanup
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Who Is Involved?
Your regulatory agencies are working
together -
U.S. Environmental Protection Agency (EPA) -
responsible for making cleanup decisions under federal
Superfund law
Washington Department of Ecology (Ecology) -
responsible for making cleanup decisions under state
Model Toxics Control Act and leading effort to control
upland sources of pollution
Studying the waterway cleanup options
Lower Duwamish Waterway Group (LDWG), a
partnership of City of Seattle, King County, Port of
Seattle, and The Boeing Company, working under EPA
and Ecology oversight
Responsible for paying for cleanup
To be determined, but including public agencies,
businesses, and property owners
Providing community and natural resource
perspectives -
Duwamish River Cleanup Coalition (DRCC) - EPA
and Ecology-funded community advisory group active in
local community outreach
Native American Tribes - advising EPA and Ecology on
tribal resource protection
Natural Resource Trustee Agencies - responsible for
ensuring the protection and restoration of natural
resources
Voices from the community and region
Community, conservation, business, and civic groups -
providing input on the cleanup options
YOU - learning more and providing your thoughts and
concerns to be considered by EPA and Ecology as they
propose a specific cleanup plan in 2012
Your health agencies -
Providing information on protecting you and your family
from health risks (www, d o h. wa. g ov/eh p/o eh a s/fis h/
consumpadvice.htm#Lower Duwamish Waterway: and
www.epa.gov/region 10/pdf/sites/ldw/doh factsheet
nov2007.pdf
How You Can Make a
Difference
Waterway pollution and health risks, and the cleanup
options to reduce those risks, are difficult and
complex. This fact sheet gives a short explanation to
help you understand the cleanup options.
More detail is available online (www.ldwg.org) in
the full length Feasibility Study and its executive
summary. Give your input by email or the online
comment form. Or check the hard copies at EPA
offices and Seattle Public Libraries (Downtown
and South Park)
EPA, Ecology, the Lower Duwamish Waterway
Group, and Duwamish River Cleanup Coalition,
will be out in the community at neighborhood
meetings and events to answer questions and
hear your thoughts and concerns about the draft
Feasibility Study.
Public meetings on Tuesday, December 7
(Concord Elementary School, 4:30-8:30 p.m.)
and Thursday, December 9 (South Seattle
Community College, 4:30-8:30 p.m.)
Contact the Duwamish River Cleanup Coalition
for information about upcoming workshops at:
www.duwamishcleanup.org or 206-954-0218
Comments invited until December 23, 2010.
No matter how you comment, all input will be
considered by EPA and Ecology.
For More Information
Visit EPA at: www.epa.gov/region 10/duwamish. html
or Ecology at: http://www.ecv.wa.gov/programs/tcp/
sites/lower duwamish/lower duwamish hp.html
Comments and questions can be directed to
EPA's community outreach coordinators,
Suzanne Skadowski, 206-553-6689,
skadowski.suzanne@epa.gov, or Renee Dagseth,
206-553-1889, dagseth.renee@epa.gov
~ Send your comments on the cleanup alternatives
by email to: rlOLowerduwamish@epa.gov
Or
~ Comment online at www.ldwg.org
8 | Lower Duwamish Waterway Cleanup
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