III-2. TREATMENT VERIFICATION
51
Table III-2-6. White phosphorus concentrations found in
composite samples collected from grids in Area C and
the Bread Truck Pond.
Median White Phosphorus Concentration (g/g)
Date
C 100 m
BT North 100 m
BT South 100 m
4 June 1997
0.069
0.012
0.0049
4 September 1997
0.0063
0.0056
0.00087
22 August 1998
0.0074
0.0038
0.0035
15 September 1999
0.0016
0.0003
0.0045
16 August 2000
0.00055
0.0001
0.00025
in concentrations in the surface sediments
fall of 1999 to enhance the drying of Pond 146.
since the initiation of the pumping project
In August 2000, we again collected a series of
(Table III-2-7), and in August 2000, white
subsurface samples at location #53. White
phosphorus was finally undetectable in the
phosphorus is no longer detectable along the
surface sediment. In 1997 we collected two
length of the core. The highest concentration
narrow cores down to 20 cm from the center
was 0.06 g/g at a 10-cm depth (Table III-2-3).
of the crater and found high concentrations
The second set of subsurface samples were
(up to 1730 g/g) in the deepest (20-cm) part
from Miller's Hole, the crater produced in
of the core. This year we excavated two small
1992 from the detonation of a WP UXO. Re-
holes down to a 20-cm depth. Sediment from
peated sampling shows significant decreases
Table III-2-7. White phosphorus concentra-
tions found at Miller's Hole, a crater produced
by the detonation of a WP UXO (81-mm mor-
tar round). The crater center is 30 cm below
the rim.
White Phosphorus Concentration
(g/g)
Days Since
Center of
Sampled
Explosion
Crater
Rim
5/20/92
0
2,394
979
6/18/92
29
5,572
0.237
8/21/92*
93
184
0.00427
6/23/93
399
187
0.0175
8/27/93*
464
81.5
0.00177
5/16/94*
726
49.5
34.1
8/30/94
832
9.5
not detected
6/1/95†
1107
10,497
0.0051
9/17/95†
1215
166
0.0006
9/3/97
1932
1.6
not detected
8/25/98
2288
0.037
not detected
9/21/99
2681
0.0008
not detected
8/21/00
3015
not detected
not sampled
*Crater under water when sampled.
†Crater under water all summer.
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