.
pyewtel
a4
.
igh. a
7
1
-
.
.
.
Se aes mee at oy abe a
ne
neh 8 go act tpt mite beat
otne
2
.
Tehcarhate
calsekeh sonktathee Sear lg oe Cree ete
;
a
* _
.
“a
at
tae
“hoes
.
BIOLGGY AND MEDICINE
-
‘
:
i
:
:
i
‘.
ve
.
UNCLASSIFIED |||.
3. Values for powdered milk from Mandan, North Dakota, were from 4 to 17
strontium units in the first seven months of 1957. These values correspond to the
range of values observed in 1956.
,
.
U.S. Public Health Service milk monitoring program. The U.S. Public Health Service,
which keeps in close contact with the milk industry, has started a milk monitoring program, _
similar to the one conducted by the Commission, to keep informed’‘regarding the contamination
of milk by radioactive fallout.
Care is being taken to obtain representative samples. Areas with predictable and constant
dairy husbandry practicesare selected for sampling. Only fluid milk samples are collected;
these are composited from small herds and from areas containing a predetermined numberof
farms. Samples are now being routinely received from areasin California, Missouri, New
York, Ohio, and Utah; additional stations are expected to be set up in the next few months.
Analytical work is performed atthe Public Health Service’8 Robert A. Taft Sanitary Engi
neering Center, Cincinnati, Ohio. oo
an
a
.
-
2
The program of the Public Health Service was described to representatives of the AEC
and the Food and Drug Administration ata
a
meeting held on December 13, 1957.
Do
a
po
Pee
BE
vote
ot akan elo hed me ee Waa eeeee
v
Soil and Plant Research
The AEC sponsors a number of research projects on the behavior of fission products in
soils and plants. Such behavior is invéstigated in the field, in the greenhouse, in the growth
chamber, and in the laboratory... -
Experiments with different soils containingva
varying amounts of exchangeable calcium (i.e.,
an
calcium replaceable by other cations and not fixed in the soil) show that the uptake of stron-
Jot.
tium by plants decreases somewhat with an increase in the amount of exchangeable calcium
present. The same rule was found to apply to barium uptake. The uptake of cesium and ru- _
bidium, as would be expected from the periodic table of the elements, was more closely re- -
-
i
J
od
lated to the amount of acid-soluble potassium, a commonly. used index of available potassium.
A distribution factor, defined asthe ratio of strontium to calcium in‘the plant, or plant
part, divided by the ratio of available (to the plant) strontium to available calcium in the soil
or nutrient solution, was determined for certain situations. This factor serves as a measure
i
fo
i
of the relative availability of strontium and calcium, and also can be applied to other pairs of
chemically similar elements. The experiments with nutrient solutions yielded an average
strontium-calcium distribution factor for the entire plant of slightly above 1, for roots much
higher than 1, for stems, petioles, and leaves progressively less than the root values.
‘
‘The average distribution factor for natural, stable (nonradioactive) strontium versus calcium in wheat and alfalfa for a large number of.sites in the United States was about 1. Ten
crop plants grown on four soils ina greenhouse experiment had an average value of 0.7 for
the same factor.
-
_The effects of liming and tilling on the uptake of strontium 90 from an acid soil were investigated in a field experiment. When four tons of lime per acre were applied to the surface
of the soil there was no appreciable: change in the ratio of strontium to calcium in either soy-
bean plants or bluegrass. When the same amountof lime was rotary-tilled into the upper six
inches of the soil, the uptake of strontium was reduced in soybean plants but not in bluegrass.
Burial of both the lime and the strontium to a depth of 15 inches reduced the uptake of stron-
tium by soybeans even more effectively than rotary Hailing.
UNCLASSIFIED
TO
co
}
.