36 days, from July 7 to August 12, 1972,
The collected 23% 240 Pu activity was
distributed lognormally with particle
size with an activity median aerodynamic
table results reported for 236,
239, 205.
concentrations ranged from 3.5 X 10°}?
to 6.3 x10 33
uCi/em, with arithmetic
and geometric meansof 6.6 X 19° 9 and
diameter (AMAD) of 3.0 um and a geo-
7,9X 10° 16 uCi/em’, respectively.
metric standard deviation of 8.2,
sults for four soil samples taken from
The
Re-
239, 2405, concentration varied from
approximately the same location range
with an average of 2.3 X 10° 14 uCi/em 3
from 128 to 202 dpm/g, with a mean of
160 dpm/g". Because the arithmetic
1.0 x 107!4 to 3.9x 10° !4 pci/em9,
for the five samplers.
At the present
time only limited data are available regarding the soil activity in the area.
Four soil sampies of depth 0-3 cm from
approximately the same location have
-been analyzed with results?! of 2060 to
- 3550 dpm/g, with a mean of 2700 dpm/g.
mean is a better representation of average
lung exposure, it is used to derive a resuspension factor at this site:
6.6X10 uli,
cm?
2
160 dpm’
em?
1,38 ¢
x 0,9 x 10° em y 2.22 x 10° dpm .
3 cm.
m
BCI
Profile data from other locations at the
=2xX10°9/m,
same general site indicate that about 90%
This value is nearly an order of magni-
of the total deposition is contained within
tude higher than the one previously caicu-
the top 2.5 cm of the soi ?,
lated, and reflects some of the inherent
Measure-
ments of soil density in the area average
difficulties in the resuspension-factor
1.8 g/cem’ .
approach, i,e., that no allowance is made
The resuspension factor
is therefore
2.3.x 10 ** uci, _¢
-1
cm”
2700 dpm
x £m
3
1.8 g
0.9 10 cm y 2.22 x 10° dpm
x
3 cm
m
uCi
=3X10 -10 “‘/m.
Additional air samples were taken by
the Reynolds Electrical and Engineering
for the geometrical configuration of the
source and that higher ground activities
may be present upwind,
It is obvious that this approach is sub-
ject to major uncertainties, but does
serve as an order-of-magnitude indication
of the resuspended air activities that may
Q
arise from a 239, 2405, contaminated
Co, (REECo) on the edge of the contamin-
area which has weathered for 15 to 20 vr.
ated area during the period of February
The data discussed above also ce monstrate
1971 to July 1972, with a sampling time
of approximately 48 hr?
Measurements
unequivocally that resuspension of
239, 2405, does in fact occur from such
were made at four locations, but the
aged deposits and at levels mary orders
most pertinent is the one which was most
of magnitude higher than would be ex-
frequently in the direction of strong winds
from the strongly contaminated area and
where the highest air activities were
recorded,
Here, 254 individual air-
filter samples were collected and detec-
pected ir the often noted decrease with
time were represented ty a single exponential function with a half-time of 35 to 79
days.