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agricultural practices such as deep plowing.
‘This chances the position
of the fallout with respect to the rovt some of the craps.
In the case
of shallomrcoted creps such ss seme grasees and many vegetables, the
deep plowing may materially reduce the uptake ef S90,
At best, one
ean axpect only a feufeld change in uptake by the plant from these mech-
anical soll tresteents,
liming caleiwepeer scil will somewhat reduce
Sr-90 uptake by reducing the ar-90/caletum ratio.
Fresh fallout onto surface waters, streams, lakes and oceans is
quickly diiuted unlike fallout on scil which at first is concentrated
in a few tep inches and readily available te a variety af shallow rooted
plants. In fresh waters the Sr-90 4e taken up by the plant and antnal
life and eventually settles out in the lake bettas or the mid of the
yiver.
Open waters alao contain more or less soil and powered rock in
suspension which may carry the Sx-90 with it removing it by sedimentation,
In the cape of water that cones from wells and springs the Sr~-90
has been largely removed by filtration through the soils, Mixed fisgion
preduet tropespheric fallout in open lakes amd rivers has posed a probles
at the tima of fallout te certain industries like the photographia film
industry, which involve proeessss requiring larce volumes of water which
must be extrwmely low in radioactivity of any sort.
From the standpoint
of effect on man fallout into waters froaa weapons testing has not con~
stituted a major concern, although drinking water made directly from