Nam, S.I. (1995) The environmental impact of
production and buildup of the reaction product,
white phosphorus on avian species. Doctor of
P4O10, in the soil, altering the local soil porosity,
Philosophy, Dartmouth College.
and various temperature dependencies of the
White phosphorus (P4) has been implicated in
physical and chemical parameters involved. Soil
characteristics for Eagle River Flats sediments
thousands of waterfowl deaths at Eagle River
were also determined for inclusion in the model.
Flats (ERF), an estuarine salt marsh located near
Buildup of P4O10 coincides with an experimen-
Anchorage, Alaska. P4, a well-known toxicant, is
tally observed ring of discolored sediment sur-
lethal to a wide range of species. The toxic effects
rounding the initial location of P4 particles after air
of P4 have been reported in humans, numerous
drying of sediments. But, the buildup of these
aquatic species, livestock, and laboratory ani-
products in the soil is found to have no effect on
mals. However, P4 toxicity in avian species is not
the persistence process for small particles. Oxygen
well characterized, and the basic mechanisms of
depletion in the soils is also found to be negligible.
P4 toxicity are still not understood. The primary
Model simulations of particulate P4 persistence
objective of this thesis was to better understand
are also insensitive to the Kelvin effect of particle
and characterize P4 toxicity in avian species.
curvature on vapor pressure. Further, the con-
Mallards dosed with a lethal quantity of P4
sumption of P4 and oxygen by the chemical reac-
exhibited behaviors characteristic of P4 poisoning
at ERF and died within 4 hours of exposure. P4
tion only affects predicted persistence times
slightly. However, the persistence of P4 depends
tended to distribute mostly into the fatty tissues.
largely upon the sediment and particle tempera-
In an experiment designed to simulate preda-
ture, which mainly affects the vapor pressure, and
tion events at ERF involving P4-poisoned ducks,
the sediment air filled porosity.
P4 was found not to accumulate in tissues of
When compared to previous laboratory experi-
kestrels. When P4 in the diet was decreased,
mental studies on P4 persistence at low tempera-
depuration of P4 was observed.
tures and high air-filled porosities, the model
In chickens dosed with P4, rapid absorption
results show good agreement. At low air-filled po-
into tissues was observed. P4 was also detected in
rosities, a nonlinear correlation for the calculation
the eggs of chickens dosed with sublethal doses
of effective diffusion coefficients in sediments is
found to be more appropriate than the linear Pen-
receiving sublethal doses for 5 days.
man relationship. Also, at higher temperatures,
Studies were undertaken to determine if P4
the autocatalytic effect of the highly exothermic
toxicity varied with the form of P4 administered
reaction of P4 vapor and 02 and resulting tempera-
and to assess whether ducks could be therapeuti-
ture increases may explain the large deviations
cally treated for P4 poisoning. No significant vari-
from experimental data. Inaccuracies in the esti-
ance in survival time was observed between
mation of effective diffusivities may also affect
groups with either dissolved or particulate P4.
model simulations.
Short latent periods between first signs of intoxi-
Implications of model results for site remedia-
cation and subsequent convulsion argued against
tion are discussed. The level of natural attenuation
effective treatment.
of P4, verified by field data, is predicted by the
In vitro studies demonstrated that phosphine
model within reason. Conditions required for
(PH3), a toxic gas, is generated from P4 by various
assisted attenuation of saturated sediments are
rat tissues. Viable samples of blood and brain
calculated for average summer site conditions. It is
produced significantly more phosphine that did
estimated that, when appropriately drained, sedi-
heat-denatured samples, suggesting enzymatic
ments at Eagle River Flats may be decontaminated
during a single summer.
In toto, these data suggest that P4 is readily
Future work is needed to obtain an accurate esti-
absorbed from the digestive tract and that death
mate of the effective diffusion coefficient of P4 in
follows 4 to 5 hours after exposure. Toxicity may
sediments of interest. Also, the effect of the heat gen-
be ascribable more to the metabolite phosphine
erated by the exothermic reaction must be investi-
than to P4 itself. The potential for accumulation
gated further and included in the model. Soil water
up the foodchain appears limited, but the mobil-
content gradients and evaporative processes, as
ity of P4 into eggs raises concerns about possible
well as oxygen concentration gradients within the
reproductive effects and broader ecosystem
soil, are also identified as potentially important fac-
impacts.
tors to be included in future modeling efforts.
89
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