The objectives for 1995 were to monitor water-
we dosed 10-day-old poultry chicks with three pel-
fowl mortality at ERF, measure mortality in an
lets of white phosphorus over a 24-hr period.
These chicks were then euthanized and frozen.
uncontaminated reference area, measure mortal-
Later, we divided the chicks into two groups. One
ity in non-contaminated areas of ERF, and evalu-
group (NoGut) had the upper digestive system
ate mortality in swans. Mortality at ERF was com-
(crop, proventriculus, and gizzard) removed; this
pared to previous years to monitor decreasing
dissection was to remove any intact pellet from the
exposure of ducks to white phosphorus from
digestive system to determine if predators can be
either remediation efforts or natural processes.
intoxicated by tissue levels alone. The other group
We measured mortality in uncontaminated refer-
(Pell) was kept intact and a 1.1-mg pellet of WP
ence areas to develop a background level of mor-
was surgically placed into their crop; this simu-
tality so that mortality rate at ERF can be used as a
lated a prey item with undigested WP in its gizzard
measurement endpoint. Mortality was measured
or crop. A third group of chicks was undosed con-
by the same methods used since 1992. Counts of
trols. These chicks were subsequently fed to Amer-
carcasses on permanent transects were compared
ican kestrels for 7 days, when 50% of the kestrels
to the number of ducks exposed, calculated from
on the Pell diet had died. Tissue levels in chicks
censuses made each morning. Mortality on refer-
were similar to those found in waterfowl and the
ence areas was measured by the same method.
The mortality rate at ERF during fall 1995 was
1.1-mg implanted pellet represented a dose of 6.8
lower than in fall 1994. This decline continues a
10.8 mg/kg body weight in the kestrels, similar to
trend that has been seen since 1992, when the
that potentially encountered by eagles feeding on
mortality rate was approximately ten times higher
gizzards of dead or dying waterfowl. Of 15 kestrels
on the Pell diet, 8 died during the study, the first
than in 1995. The fact that the mortality rate
after only 2 days. Of 15 kestrels on NoGut diet, 3
decreased in 1995 despite an increase in exposure
also died but only on the fourth (1) and tenth (2)
rate shows that this decline does not result from
days of treatment. Pathological effects were
hazing or other activity on the Flats. Rather,
observed among survivors in both groups com-
ducks are less exposed to white phosphorus
pared to controls. Significant differences occurred
because of natural attenuation, sedimentation on
in hematocrit, weight loss, liver/body ratio, and
top of contaminated pond bottoms, or high water
causing ducks to feed in non-contaminated areas.
hemoglobin. WP was found in the tissues of
The mortality rate in spring was very low but
kestrels from both the NoGut and Pell treatments.
could not be compared statistically to previous
The study showed that predators are at risk of
years because of a low exposure rate and because
intoxication when they eat either the carcass or giz-
no carcasses were found on transects. Only one
zards of moribund and dead waterfowl.
carcass was found on transects in reference areas
in Goose Bay and Susitna Flats. Thus, back-
Development of semi-permeable membrane device
ground mortality may be as much as one tenth
(SPMD) to evaluate white phosphorus presence
that currently occurring at ERF, but more data are
in water and sediment
Preliminary steps have been completed in deter-
needed to accurately measure background mor-
mining if SPMDs can be used to monitor water and
tality. We found only one carcass on transects in
sediments for the presence of WP. A problem occurs
uncontaminated areas of ERF (Areas B and D).
in that the vapor pressure difference between WP
These areas still do not represent a hazard to
and the solvent isooctane is only 1.1 103, which is
ducks. Five swan carcasses were found, mostly
too low for reliable extraction. Therefore, n-pentane,
before swans had been observed in contaminated
which has a vapor pressure differential of 1.2 104,
areas. These deaths raise the possibility that
is being tested instead.
swans ingest white phosphorus in areas thought
to be safe for ducks: Area D, Area B, or the pond
Steele, B.B., and L.R. Reitsma (1996) Waterfowl
in Area C/D. Swans feed in deeper water than
use and mortality at Eagle River Flats. In Inter-
ducks and may be exposed in different areas than
agency expanded site investigation: Evaluation of white
ducks are.
phosphorus contamination and potential treatability at
The fact that the mortality rate continues to
Eagle River Flats, Alaska (C.H. Racine and D. Cate,
decline before full-scale remediation has begun
Ed.). CRREL Contract Report to U.S. Army, Alaska,
suggests that the no-action alternative may be
Directorate of Public Works, FY95 Final Report, p.
sufficient to remediate at least some areas of ERF.
157174.
66
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