Reliable analytical methods (solvent amounts,
ture levels, which may be unattainable in the
extraction times, and sub-sample size) were devel-
field. Drying, however, may be a suitable treat-
oped to extract WP particulates from ERF sedi-
ment of dredge spoils.
ment samples. In the field, one 20-cm3 extracted
ERF environment. As an estuarine salt marsh,
subsample from each 500-cm3 jar containing the
Eagle River Flats is an extremely important, pro-
sediment sample provided a reliable determina-
ductive, and dynamic ecosystem that supports a
tion of the presence or absence of WP but is less
broad range of habitats and species (over 50 bird
reliable in representing the actual concentration of
species were observed to use the area) and
WP in the total 500-cm3 sample.
involves complex physical, chemical and biologi-
Over 400 pond-bottom surface sediment sam-
cal processes.
ples were collected at 25-m intervals along
A geographic information system, combined
transects in the six waterfowl feeding pond areas,
with remote sensing techniques, was developed
representing only 5% of the total area of ERF. The
to manage and display the large amount of sedi-
bottom sediments of two of the six sampled water-
ment sample data and other environmental
fowl feeding ponds contained a high percentage of
habitat baseline conditions important for future
WP-positive samples. In addition the WP concen-
cleanup efforts in ERF.
trations of samples from one of these ponds (Bread
The pond-bottom invertebrate fauna and seed
Truck Pond) were significantly higher than those
banks have been characterized.
from the other ponds. Area C and the Bread Truck
Ponds, covering an area of about 15 ha (37 acres),
Racine, C.H., M.E. Walsh, C.M. Collins, S. Tay-
are hypothesized to be the major sources of WP
lor, B.D. Roebuck, L. Reitsma, and B. Steele
duck poisoning in ERF. Over 350 hours of observa-
(1992) Remedial investigation report for white
tions of dying ducks and predation on them also
phosphorus contamination in an Alaskan salt
supports this hypothesis.
marsh. CRREL Contract Report to the U.S. Army
The bottom sediments of the two contaminated
Toxic and Hazardous Materials Agency, Aber-
ponds in ERF likely contain a large number of very
deen Proving Ground, Maryland USATHAMA
small WP particles (<0.1 mm) and a small number
Report No. CETHA-IR-CR92004.
of much larger particles (1 mm). The larger parti-
In 1990 personnel from CRREL and Dartmouth
cles could provide a lethal dose (around 0.25 mg)
College proved that an annual waterfowl dieoff
for a small duck such as a green-winged teal. The
at Eagle River Flats (ERF), an Alaskan salt marsh,
very small WP particles in the sediments can be-
was attributable to the ingestion of highly toxic
come suspended in the water column and could
particles of white phosphorus (WP), which
provide another source of exposure for water-
entered the bottom sediments of shallow ponds
birds, fish, or plankton. WP poisoning of non-
as a result of past artillery training with WP-
waterfowl species, particularly phalaropes, was
containing incendiary munitions. During 1991,
documented; however, extensive areas of mud-
the 1990 hypothesis that WP is the cause of water-
flats used by migrating shorebirds in ERF were not
fowl mortality in ERF was strengthened by: 1) the
sampled and could contain WP. High rates of pre-
positive identification of WP in the tissues of an
dation and consumption of WP-containing duck
additional 38 dabbling ducks, 4 swans, 9 shore-
carcasses by bald eagles, herring gulls, and ravens
birds and 1 eagle (all 63 bird carcasses from ERF
indicate that these species are at risk. WP was
analyzed during 1990 and 1991 have tested posi-
detected in the tissues of a dead bald eagle found
tive for WP); and 2) the finding of WP in an addi-
in ERF.
tional 116 sediment samples collected from the
Evidence suggests that WP is transported with-
bottom of shallow waterfowl feeding ponds.
in (and to a very limited extent, out of) ERF in
During the 1991 spring and fall waterfowl mi-
birds that have ingested WP but can still fly. Dead
gration periods, intensive sediment sampling
waterfowl found in ponds without detectable WP
and avian field studies were conducted around
could have ingested the WP in either Area C or the
constructed blinds in the six waterfowl feeding
Bread Truck Pond and flown to and died in one of
pond areas where dabbling ducks feed and where
these other areas. Human health risks through
most carcasses have been found. Sediment and
consumption of ducks shot in nearby Cook Inlet
tissue samples were analyzed for WP in a nearby
marshes were found to be minimal; there was no
field laboratory. Experiments with contaminated
detectable WP in over 300 hunter-harvested duck
sediments and WP were also conducted in the
gizzards collected in September 1991.
laboratory at CRREL.
59
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