Symposium on Cold Regions Development, American
food items such as seeds or invertebrates selected
Society of Civil Engineers, 410 May, Anchorage,
by ducks. Since a lethal dose of white phosphorus
Alaska, p. 179182.
is on the order of 1 mg/kg of body weight, the
Eagle River Flats is an estuarine salt marsh
ingestion of one particle can be fatal to a duck.
located on Ft. Richardson near Anchorage,
Alaska. For 50 years, it has been used as an ord-
confined to four small pond areas totaling
nance impact area by the Army. During the 1980s,
approximately 30 ha. Our findings are significant
large die-offs of waterfowl occurred in this area
since Eagle River Flats is the first artillery training
during spring and fall migrations. For 5 years,
area identified to be contaminated with white
various state and Federal agencies tried without
phosphorus. Previous to our investigations,
success to unravel the mystery of this high mor-
white phosphorus was thought to be nonpersis-
tality. Finally, in the spring of 1990, a group of
tent in the environment because it is thermody-
researchers from CRREL, working in conjunction
namically unstable in the presence of oxygen.
with the Ft. Richardson Directorate of Public
However, the anaerobic sediments of a wetland
Works, Environmental Branch (DPW-EV), discov-
provide ideal conditions under which white
ered that white phosphorus was the cause of the
phosphorus can persist indefinitely.
waterfowl mortality. White phosphorus (P4 or
WP) has been used in the past by the Army as a
Collins, C.M., and M.E. Walsh (1995) The effects
targeting and obscurant round.
of environmental conditions on the persistence of
Eagle River Flats is part of the Ft. Richardson
white phosphorus particles in Eagle River Flats,
Superfund site, and this work was performed in
Alaska. In Proceedings, The 1995 Annual Conference
accordance with the U.S. Government Compre-
of American Water Resources Association, 67 April,
hensive Environmental Response, Compensation, and
Juneau, Alaska, p. 57.
Liability Act. The primary sponsor is the U.S.
Eagle River Flats, Fort Richardson, Alaska, is
Army Environmental Center, Aberdeen Proving
the first Army training area identified with white
Ground, Maryland. Support was provided by the
U.S. Army Corps of Engineers, Alaska District,
rus is highly toxic and has been responsible for
and the U.S. Army Alaska (DPW-EV).
large numbers of waterfowl deaths in Eagle River
Flats. Recent surveys at other army training areas
have also revealed white phosphorus contamina-
Collins, C.M., C.H. Racine, and M.E. Walsh
(1992) White phosphorus contamination of an
tion. Previous to our findings at Eagle River Flats,
Alaskan salt marsh: Eagle River Flats. In Proceed-
white phosphorus was thought to be nonpersis-
ings, American Water Resources Association--Alaska
tent in the environment, indicating that the cur-
Section Annual Meeting, 910 April, Fairbanks,
rent understanding of the environmental fate of
Alaska, p. 99.
white phosphorus is poor. White phosphorus
In 1990 we identified elemental or white phos-
particles up to several millimeters in size were
deposited in the salt marsh sediments of Eagle
phorus as the toxicant responsible for the death of
River Flats from the incomplete combustion of
several thousand dabbling ducks each year in
Eagle River Flats, a salt marsh wetland on Ft.
white phosphorus smoke munitions. Remedia-
Richardson. Eagle River Flats is the artillery
tion of sediments at Eagle River Flats may require
impact area for Ft. Richardson and the white
severe alterations of the wetland by dredging,
phosphorus particles were deposited from smoke
draining, or covering. However, some sediments
projectiles fired into the impact area. Burning
may undergo decontamination naturally in areas
white phosphorus is extinguished when im-
that are seasonally subaerially exposed. To pre-
mersed in water, leaving a significant amount
dict the persistence of white phosphorus in sedi-
(1030%) of unreacted white phosphorus in the
ments, laboratory and field experiments were
burn residue. The saturated sediments and anaer-
conducted. White phosphorus particles were
found to be persistent indefinitely in saturated
obic conditions found in the shallow ponds with-
sediments. In unsaturated sediments, loss was
in the salt marsh leads to the preservation of the
rapid (within 24 hours) at 20C, and retarded by
unburned white phosphorus. Particles of white
phosphorus isolated from the fine silt and clay
low temperatures. This information is being used
sediments ranged from 0.26 to 2.9 mm in length.
to plan remediation strategies for Eagle River
Most of the particles isolated were greater than
Flats. Limitation of remedial actions to those
0.5 mm in length, and thus are in the size range of
areas where white phosphorus is persistent and
22
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