EAGLE RIVER FLATS FY 00
46
Table III-2-3. White phosphorus concentra-
Sublimation/Oxidation Conditions
We installed sensors and dataloggers to
tions found in subsurface samples collected
monitor sediment temperature and moisture
at site #53 (Figure III-2-3) in Area C.
conditions using the same configuration of
White Phosphorus Conc. (g/g)
sensors as in 1997 for most of the stations. At
each station (Table III-2-4, Fig. III-2-3, III-2-5,
Depth
1992
1999
2000
III-2-8), sediment temperatures were moni-
Surface
9.83
1.43
0.0051
tored at 5- and 10-cm depths using Campbell
5 cm
179
1.16
0.060
Scientific (Logan, UT) Model 107B soil/wa-
10 cm
0.13
0.003
0.0009
ter thermistor probes. Sediment moisture con-
15 cm
198
0.020
0.0002
20 cm
0.116
not detected
ditions were monitored at 5- and 10-cm
25 cm
0.015
not detected
depths using Campbell Scientific Model 257
30 cm
0.016
not detected
(Watermark 200) soil moisture sensors. Out-
put from both sets of sensors was taken ev-
ery 10 minutes, and the hourly and 24-hour
averages were recorded by a Campbell CR10
terial remaining on the sieve was placed in a
Measurement and Control Module and an
septa jar and equilibrated at room tempera-
SM716 Storage Module.
ture. To determine if white phosphorus par-
Tensiometers provided another measure of
ticles had been retained on the sieve, we
s u r f a c e sediment moisture conditions.
SoilMoisture (SoilMoisture Equipment
performed headspace solid-phase micro-
Corp., Santa Barbara, CA) Series 2725 tensi-
extraction (SPME) followed by gas chroma-
ometers equipped with dial gauges were in-
tography (M.E. Walsh et al. 1995a).
stalled, one at 10-cm depth and another 20-
Discrete samples were subsampled by tak-
cm depth at most sites, and they were read
ing a 40-g portion of each soil and extracting
periodically by Dave Mitchell (Weldin Con-
the white phosphorus with 20 mL of isooc-
struction). A third tensiometer was equipped
tane. Subsurface samples, which were ob-
with a pressure transducer and wired to the
tained in the field with corers, were placed
datalogger where hourly and 24-hour aver-
directly in isooctane. After shaking overnight,
ages were computed and recorded on a stor-
the extracts were analyzed by gas chromatog-
age module.
raphy (EPA SW-846 Method 7580).