Section 319
NONPOINT SOURCE PROGRAM SOCCER STORY
Water Quality Restored at Eagle River Flats to Revive Bird Population
Waterbodv Improved A military base's munitions use led to a buildup of white
y ^ phosphorus particles in the sediments of Eagle River Flats
(ERF), causing a high mortality rate in transient waterfowl populations. Alaska Department
of Environmental Conservation (ADEC) placed the ERF on Alaska's 1996 and 1998 Clean
Water Act section 303(d) lists of impaired waters because it violated the toxic and other
deleterious organic and inorganic substances water quality standard. Based on EPA's
approval of the U.S. Army's restoration plan through Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA), ADEC moved this water to Category
4b ("impaired water with other pollution controls") in its 2002 Integrated Report. To restore
the ERF, the U.S. Army seasonally drained the marsh and capped the polluted sediment
layer to reduce saturation of the soil and increase soil temperature. These actions helped
to successfully sublimate the white phosphorus (change it from a solid to a gaseous state)
and render it harmless to the local waterfowl populations. As a result of meeting the water
quality goals set by CERCLA, the ADEC removed toxic and other deleterious organic and
inorganic substances from the list of impairments in 2008.
Problem
ERF is an 865-hectare estuarine salt marsh
that is completely within the boundaries of Fort
Richardson Army Base along the upper Cook Inlet
in Anchorage Borough, Alaska. Ongoing high
waterfowl mortalities at ERF were first noted in
the early 1980s. After initial sampling between
1983 and 1988, an interagency group consisting
of the U.S. Army Environment Hygiene Agency,
ADEC, U.S. Environmental Protection Agency (EPA),
and Environmental Science and Engineering, Inc.,
concluded that the source of the problem was
munitions from Fort Richardson, which had used
ERF as its primary munitions impact area since the
1940s. The U.S. Army suspended the use of ERF as
an active Army impact area in 1989.
In 1990 scientists from the U.S. Army Cold Regions
Research and Engineering Laboratory (CRREL) pin-
pointed white phosphorus as the cause of the birds'
decline. This compound, present in the smoke
rounds used in Fort Richardson's munitions train-
ing, typically oxidizes quickly in the air and was not
initially considered persistent in the environment or
harmful to wildlife. However, CRREL showed that
the environmental conditions at ERF, including the
soft, anoxic sediments and frequent deposition of
sediment by flooding, contributed to the long-term
stability of the white phosphorus as granules. As
waterfowl fed on insects and seeds in the water and
sediment, they also ingested the toxic white phos-
phorus granules. Ingestion of just a few milligrams
of white phosphorus by waterfowl is lethal.
ADEC first placed 60 acres of the contaminated river
flats on its 1996 section 303(d) list for not support-
ing its designated use of growth and propagation
of fish, shellfish, other aquatic life and wildlife. It
remained listed for subsequent years.
Dabbling ducks, the waterfowl species most in
decline from the contamination, served as the bioin-
dicator for water quality impairment. The Army set a
five-year goal of a 50 percent reduction in waterfowl
mortality of the fall population of dabbling ducks
and a longer term goal of a total mortality rate of
one percent within 20 years. One percent mortality
represents the natural mortality rate and the mea-
sure of successful remediation for this cleanup.
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Project Highlights
In 1994 ERF became a federal Superfund site and
was subject to the remedial response require-
ments of CERCLA. Between 1998 and 2007,
the Army implemented numerous water quality
restoration projects, including draining the marsh
and applying AquaBlok (to cap the sediment and
prevent contaminants from entering the water col-
umn). During each field season, the Army placed
six pumping systems into the contaminated ponds
and drained them (Figure 1). This reduced the
saturation of the soil and increased soil tempera-
ture, helping to sublimate the white phosphorus
and render it harmless to the local waterfowl
populations.
Figure 1. The Army placed pumping systems
such as this one into the marsh to drain the
water and allow the white phosphorus to oxidize
into a harmless state. For more images of the
restoration project, see www.crrel.usace.army.
mil/erf/photographs/photos-remediation.
concentrations in more than half the total acreage
identified as contaminated. Because the site met
the CERCLA milestones and waterfowl mortality
returned to levels typical for the species in this
area, ADEC no longer considers ERF impaired for
toxic and other deleterious organic and inorganic
substances and removed that pollutant from the
list of impairments in 2008.
Table 1. Summary of data showing
reductions in white phosphorus
concentrations in the surface sediment of
a crater in an intermittent pond that was
pumped during ERF restoration efforts
Date Collected
May 20, 1992
August 21, 1992
August 27, 1993
August 30, 1994
September 17, 1995
Septembers, 1997*
August 25, 1998
September 21, 1999
August 21, 2000
September 11, 2001
September 15, 2003
WP Cone. (ng/g) in Crater Bottom
2,400
180
82
9.5
170
1.6
0.037
0.0008
< 0.0002
< 0.0002
< 0.0002
• 1997 was the first year of active remediation by
pond pumping.
Results
As of 2002, the Army had met its five-year goal of
a 50 percent reduction in waterfowl mortality of
the dabbling ducks' fall population. By 2006 the
Army had met its long-term goal of a one percent
total mortality rate for the fall dabbling duck
population. In addition, the Army sampled ponds
and found that white phosphorus concentrations in
the surface sediments were below baseline levels
(see Table 1). Results of the field activities to date
show a dramatic decrease in white phosphorus
Partners and Funding
The ERF Interagency Task Force included members
from the U.S. Army, EPA, the U.S. Fish and Wildlife
Service, the Alaska Department of Fish and Game,
the ADEC, and the U.S. Army Toxic and Hazardous
Materials Agency, now known as the U.S. Army
Environment Center. The Army estimated the capi-
tal costs, operations and maintenance, and long-
term monitoring at $12.5 million for this remediation
project.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001K
September 2008
For additional information contact:
Louis Howard, Remedial Project Manager
Alaska Department of Environmental Conservation
Division of Spill Prevention and Response
Contaminated Sites Program: Federal Facilities
907-269-7552 • louis.howard@alaska.gov
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