-3-
Tete rmnceMe ran
tee
ee
Some possibilities of an attack of this sort on the problem of ar??
accumulation in the soil can be shown from ae few pleces of data that are presently
available..
~%
_ As Calculation of ‘soit/atx ratios of RaD at eshington, D.C.
. (asta from
NRL Report 4069): _
mae
wt
Someae
_ RaD inrainvweter =+ 20aja (June-Rovember 1950)
oes
_, Reinfeld at Washington = 43"/year
a
cea ee
eo ae
~
em,
S 27 gallons/sq. ft.
-'+MotelRaD deposited _¥ 540 d/m/sq. ft.
wast
~
~
If this rete of deposition ie continued for |a number of years02 oy), en
AGA}
equilibrius velue of RaD in the soil wild be attained as given by the relation:
ft.
“nan (Wa/re®) »BB40 alee, . Celera
naoh
er
Air concentration of RaD 7 & x 106+
a/m/ou. ft.
Soil/air ratio =. eT 10", - 4x10!
...
Bs
Whether ratios of any great accuracy can be obtained will be dependent
Gn finding suitable soil samples of low radium content. _
7
_ Fa content of "average" rock “= lx yo~+# e/g of soil (varies from~5 x 10722
for some granites to as low as 0.12 x 107° for certain chalks, etc.)
Re = Rn = RaD activity «1x 1071? C/g x 2.2x 10°? d/mn/C
.
= 2.2 d/m gram of soil
Yor a1 ft. square soil sample 1 inch deep there are 2360 ec of soil or
~ 6000 grams of soil
,
‘
_ ©- Top inch of “normal” soil would contain 13,000 d/m of RaD assuming no gain \
or Joss of Rn and its decay products (range 65,000 to 1600)
-Ghe radioactivity profile of the soil at Washington can thus be depicted
echpatically as:
N