samples of soil of depth O — 3 cm were taken in the approximate area and
8
give values of 2900, 3550, c060, and 2290 dpm/g ; mean = 2700 dpm/e.
profile data are available,
so in order to calculate the total deposition we
make the conservative 25sumption that no udditional
239Pu
is below 3 cm.
measured value of soil density in the area is 1.8 g/cm? v
-
deposition is 1.5 x 19
8
re
apm/m”
0.052 dpm .
m?
No
A
Therefore, the
and the resuspension factor is
2
m~
*T.5 x 109 dpm
_
3.x 10
-10
m
Additional data were taken by REECo on the edge of the contaminated area
during the period of February, 1971, to July, 1972, with a sample period of
approximately 48 hours”.
Measurements were made at four sites, but the site
of most interest is the one in the prevailing direction of the strong winds.
Here, 254 measurements were made of which 236 gave detectable results.
Values
range from 0.000077 to 1.4 dpn/m, with arithmetic and geometric means of
0.014 and 0.0018 dpm/m>, and a median of 0.0014
dpm/m>.
Four soil activity
values in the general vicinity are 128, 142, 172, and 202 dpm/g.
The average ~~
deposition level, calculated as before is therefore 8.7 x 10° apm/m*,
As most
of the air activity samples were made over equal time periods, the arithmetic
mean would be appropriate for deriving a resuspension factor:
2
Q.0lb
3
X em
Bx 100 apm =
-9
2x107/m
The fact that the latter value is higher than the former may reflect one
of the inherent difficulties in the resuspension factor approach; i.e., that
no allowance is made of the geometrical configuration of the source and that
higher ground activities are present at upwind locations.