Ll.
For granite
2.
,
Sucfens og Sot
"73,000 dn [4r”
i”
70,000
1"
68,000
FE
_- 65,000 .
n 65,000 _
Secrets of ttt
1"
9600 h/mJef *
1"
6600
en
4600
}
1600
exceas 17,000 d/m
" ; per aq. ft.
a
oo
a
For chalk
.
oO!
BC
we
1600
—
65,000 eae eg
{600
It is obvious thatthe loss of radon from granites could complicate the
picture excessively and that no accurate determinations of the 4ccretion of RaD
could be made.
However, on low radium-content soils loss of Rn would not be such
4& serious factor and reliable figures could be obtained.
Other areas of the world should show depleted zones in the top layers of the
oil due to the excess of diffusion over deposition.Ovex the earth as a vnole-
land plus sea - there can be no overallgain or loss., This means that therewill
be @ pattern of RaD in the top layers of the soil which differs from the Uraniunradium distribution.
.
,
oe
pet
|
_ €.. Galeulation of 9 levels in Washington, D, C. soils through use of |
above epproach.
Strontium-90 air concentration at NRL (May-July 1957) = 5.1 x 107* a/m/ft.?
If seme mechanism holds for deposition of Sr’ aa for deposition of RaD,
the same soil/air factor can be used,
‘The mechaniam should be the same since both
types of activity are long-lived, Serprobably attached to extremely small uncharged
particles, are present st ground-level (or in the lower &
removed primarily by rain.
xheyoarrivexnt
atmosphere) and are
‘The only difference involWed is the manner in which