Evening star., 1953-02-16
Flowers Are a Guide
To Uranium Deposits
Certain Types Con Tolerate
Soil Containing Element
By Thomas R. Henry

By Thomas R. Henry
Flowers, lilies and mustards which
can tolerate considerable concentra-
tionS Of uranium bearing ores in the
soil constitute a distinct group.
Recognition of them may be Of con-
siderable help in locating deposits Of
the atom-bomb element for which in
tenSive prospecting now Is in progress
all over the world.
This finding has just been reported
in the American Journal of Science
by Helen L. Cannon Of the United
States Geological Survey after q two
year study Of the vanadium areas Of
the Colorado plateaus. Americas chief
native source Of the element.
Most significant Of the uranium in
dicatorS are the milk vetch, common
plant of the Rocky Mountain area,
and the princes plume, tall plant
with conspicuous spikes of yellow flow-
ers. The uranium vegetation includes
also such plants as rice, grass, woody
aster. salt bush, rabbit bush, mormon
tea, sagebrush, pinyon and juniper, the
latter sending roots down as much as
30 feet to reach water.
Milk Vetch Is Best.
Best of all the indicators. according
to the report, Is the milk vetch. It
may. indicate the presence of uranium
as much as so feet below the surface.
The existence Of any of these plants.
of course. is not certain indication
Of the presence Of the element. But
it may be good tipoff and areas
where these plants grow can be To-
Gated by air surveys.
Salt bush. woody aster and rice grass
are good indicators because those found
growing in uranium areas are Of diff
ferent species from those which ordi-
narily grow in other localities. Some
may have evolved to the point where
they need uranium. Others may just
have acquired the ability to tolerate it.
There is curious and unexplained
relationship between the uranium
plants and the "Selenium tolerators."
The element selenium, allied to sulfur.
is quite abundant in some Rocky Noun
tain areas. Ordinarily it is quite poison
GUS to plant growth. Some plants, in
cluding grasses, have acquired the
ability to tolerate it. perhaps even to
require It. When cattle and sheep eat
these forage plants they are affected
with a curious disease which has con-
stituted a considerable problem to stock
raisers. There is, however. no known
relationship between selenium and
uranium. The two elements do not nec-
eSsarily occur in the same localities.
Perhaps the common element in the
plants is the ability to acquire tolerance
to elemental poisons.
Other plants may grow in uranium
areas but they show a considerable
tendency towards whitening and dwarf
ing, according to the report. The exact
effect Of radioactivity on plant growth
still is somewhat debatable. A year or
two after the bombs were dropped on
Nagasaki and Hiroshima extremely
lush growth over the bomb-wrecked
areas was reported. Whether these re-
ports were entirely accurate is now
questionable.
Experiments IncOnclusive.
Partly because of them, extensive
experiments were undertaken by the
United States Department of Agricul-
ture on the possible stimulating effects
of small amounts Of mildly radioactive
material mixed in the soil. For the
most part, the results were negative.
No harm was done, however. and that
there was slightly stimulating effect
still is open to debate.
There is no question, however, that
large amounts of radiation would be
detrimental and probably fatal to most
plants. These. like animals. would vary
from individual to individual in their
ability to withstand the cell destruction.
Thus would be put in effect the law Of
survival of the f1ttest and the building
up Of especially adapted species. Some
thing Of the sort may have happened
in the Colorado plateau region with
its widespread, but not very rich, de-
posits of the canary-yellow mineral
carnotite, a mixture of phosphorus,
vanadium and uranium-the major
United States source of the atom-b bomb
element.
Since intensive prospecting started.
these carnotite deposits through the
Rocky Mountain area have been found
to be much more extensive than for
merly was supposed, and the search for
them has become a major activity Of
the atomic energy program.