III-2. TREATMENT VERIFICATION
37
III-2. TREATMENT VERIFICATION: MONITORING
THE REMEDIATION OF WHITE-PHOSPHORUS-
CONTAMINATED SEDIMENTS IN TREATED PONDS
Marianne E. Walsh, Charles M. Collins, and Ronald N. Bailey
U.S. Army Cold Regions Research and Engineering Laboratory
Pond (Fig. III-2-1, III-2-2) to monitor sublima-
INTRODUCTION
tion/oxidation conditions and for baseline
and verification sediment sampling (M.E.
The white-phosphorus-contaminated sedi-
Walsh et al. 1998). Three transects were estab-
ments at Eagle River Flats are remediated by
lished, one in Area C (Ponds 164 and 183) and
pumping selected ponds and allowing the
two in the Bread Truck Pond (Ponds 99 and
sediments to dry. The 2000 season was the
109). Along each west-east transect at 0, 50,
second year of treatment under the Record of
100, 150, and 200 m, composite samples were
Decision signed in September 1998, although
collected to determine if hot spots (localized
Pond 183 in Area C was pumped in 1997 and
areas containing white phosphorus particles)
1998 during the development of the pump-
were present. Each composite sample was
ing procedure. Coinciding with the develop-
made up of 92 sediment cores obtained at the
ment of the treatment methodologies, we de-
nodes of a 1.82-m square grid covering a 5.46-
veloped a variety of methods to monitor the
m-wide area extending 20 m north and south
success of the remediation. Sublimation/oxi-
of the west-east transect. For each of the three
dation conditions are monitored using sen-
transects the highest white phosphorus con-
sors linked to a datalogger, discrete and/or
centrations were found in the middle of the
composite surface sediment samples are col-
ponds (samples taken at the grid 100 m along
lected from known areas of contamination to
the transect). In August 2000 we again
see if the concentrations have declined with
resampled these grids (C 100 m, BT South 100
time, and residual white phosphorus from
m, and BT North 100 m) (Fig. III-2-3) and col-
planted particles is measured to see if loss
lected composite samples, which were made
occurred.
up of subsamples (31 mL, 2 cm diameter, 10
cm long) from the nodes of grids extending
north and south of the transect.
METHODS
Pond 155 (Northern C)
Composite Sampling
Pond 155 is a small, 0.35-ha (0.70-acre) per-
Pond 183 (Area C) and Pond 109 (BT Pond)
manent pond (Fig. III-2-1, III-2-3) located
In 1997 we established 200-m-long west-to-
north of pond 183 in Area C (Pond 183), where
east transects in Area C and the Bread Truck
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