phorus (P4) in sediment and water. In Proceedings,
and was not concerned with environmental fate.
Lack of understanding of the environmental fate
11th Annual Waste Testing & Quality Assurance
and transport of white phosphorus residues pre-
Symposium, 2328 July, Washington D.C., p. 380
cludes accurate ecological assessments and effi-
387.
cient cleanup. Remedial techniques currently
White phosphorus (P4) can produce severe
under investigation at Eagle River Flats (ERF)
adverse ecological impacts if released into envi-
include dredging, covering, and pond draining,
ronment. First produced in the United States over
all of which involve changing the salt marsh hab-
100 years ago for use in matches, and subsequently
itat. Limitation of remedial actions to those areas
for rat poisons and fireworks, today it is primarily
used in the production of phosphoric acid and as a
threaten wildlife would make the remedial pro-
smoke-producing munition. To date, there is no
cess more efficient and less controversial. Studies
standard analytical method for white phosphorus
were conducted on the persistence of white phos-
in environmental matrices. We have been using an
phorus residues in sediment. Specifically, the ef-
analytical method based on solvent extraction and
fect of sediment moisture and temperature on the
gas chromatography to determine white phospho-
persistence of white phosphorus particles was in-
rus in sediments and water from an Army training
vestigated under laboratory and field conditions.
area. For sediments, a method detection limit of
less than 1 g/kg was achieved for white phos-
phorus extracted with isooctane and determined
Walsh, M.E., C.H. Racine, C.M. Collins, and B.
Nadeau (1993) Factors that determine persistence
with a portable capillary gas chromatograph
equipped with a nitrogen-phosphorus detector.
of white phosphorus residues in a wetland im-
pact area. In Proceedings, SETAC 14th Annual Meet-
For water, extraction with isooctane may be used
to determine concentrations greater than 0.1 g/L.
ing, 1418 November, Houston, Texas, p. 265.
Eagle River Flats is an estuarine salt marsh on
However, to meet water quality criteria for aquatic
Cook Inlet, Alaska. Since the 1940s, the marsh has
organisms, preconcentration of the solvent extract
is required. Owing to the relatively high vapor
been used by the Army as an impact area for artil-
pressure of white phosphorus, a nonevaporative
lery training. Training with white phosphorus
preconcentration step is used. P4 is extracted from
(P4), a smoke-producing munition, has resulted
in contamination of the sediments of shallow
water using diethyl ether (10:1 water:solvent
ponds in Eagle River Flats. Thousands of water-
ratio). The ether phase is collected, then reduced
fowl die each year at Eagle River Flats after feed-
in volume by shaking with reagent-grade water.
ing in these ponds. Evidence will be presented
By using the appropriate volume of water, excess
that the P4 is in particulate form in the sediments,
ether is dissolved away, resulting in a preconcen-
and that the particles are similar in size to seeds
tration factor of 500 while heat is avoided and loss
and invertebrates ingested by waterfowl and to
of P4 by volatilization minimized. Using this pre-
grit used by waterfowl. Factors that determine
concentration procedure, a method detection limit
of less than 0.01 g/L was achieved.
the persistence of these particles include sedi-
ment porosity, moisture content, and tempera-
To minimize use of solvent in the laboratory,
solid phase microextraction (SPME) may be used
ture. These factors interact to determine the rate
at which the P4 particles sublime to form P4
to screen samples for contamination. Exposure of
a 100-m polydimethylsiloxane phase to the head-
vapor. Previous models and studies of P4 persis-
tence in soil have focused on the availability of
space above a sediment or water sample for 5 min-
oxygen. Oxidation of P4 is a vapor phase reaction,
utes, followed by thermal desorption in the injec-
thus sublimation must precede oxidation. While
tion port of the gas chromatograph, provides
oxygen is important in the detoxification of P4,
sensitivity similar to that obtained by solvent
the principal mechanism determining the per-
extraction. Since this method is based on equilibri-
sistence of P4 particles is the rate at which the P4
um partitioning between the sample, headspace,
sublimes. Oxygen may actually slow sublimation
and solid phase, response is matrix-specific. Work
by the formation of oxidation products around
is in progress on calibrating this procedure for
the P4 particles that impose a diffusion barrier to
quantitative analyses.
P4 vapor.
This analytical method will be proposed for
inclusion in SW846 Update III as Method 7580:
White Phosphorus by Solvent Extraction and Gas
Walsh, M.E., S. Taylor, D. Anderson, and H. Mc-
Carty (1995) Analytical methods for white phos-
Chromatography.
32
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