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UNCLASSIFIED | _ 7 o : . aS
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Experiments have beenconducted to find out what happens when‘strontium Js applied to
various leaves of a plant. Strontium appears in other aboveground parts of theplant, and
measurements can be made of: the relative amounts.
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The extent to which strontium 90 is fixed (made relatively unavailable to dants)
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in soils
in nonexchangeable forms is under investigation. Samples taken in 1955of onel oil from Ohio
exhibited fixation values ranging from zero to 20 percent of the total strontiumg 90 content, —
Comparable samples of a different soil collected nearby showed values ranging up to about
10 percent. Incomplete data on soil samples from North Carolina indicate a mpximum value
of 35 percent, higher than the Ohio values.
A leaching experiment with five soils: showed that dilute solutions of calcikm salts are
much more effective inthe leaching of radiostrontium than are sodium salt_sofutions (common
table salt is one sodiumsalt) or plain water alone. In general, the coarser thq soil, the greater
the downward movement of strontium when the rate of flow of the water and sdlutions is not:
- excessive.’ For neither strontium or cesium,on which experiments were alsc conducted,-is the
rate of movement fastenough to suggest leaching with dilute solutionsaas ara pid method for
decontaminating soil.
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Experiments with a fine eandy soil show that relatively large amounts of. hydrochloric acid
applied to the surface of the soil are effective in leaching out strontium. Othe chemicals ap- plied in equivalent amounts, ferric chloride, calcium chloride, and strontium[chloride, were
not so effective, and sulfuric acid, aluminum chloride, and sodium chloride were even: less
effective. In all cases except hydrochloric acid, an appreciable fraction of
strontium *remained in the soil:where the chemicals were applied, indicating that some of e strontium had
become fixed.
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Field studies «on soil decontamination have been carried out using some if
¢ the chemicals
listed above. The chemicals were applied to the soils which were then irrigated with water to
a depth of five feet; the distribution of strontium 90 and salt to a depth of thrpe feet was then
determined. Hydrochloric acid again was most effective, and ferric chloridejalso was effective
in removing strontium from surface layers. It was concluded that decontam ation of soils by
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any of these treatments would be expensive.
For this reason, physical removal of surface deposits of fission produc Ss has been studied.
One method involves spraying the soil first with a material to enclose and h 1d onto the contaminants and‘surface soil. It was found that 97 percent of the radioactivity ould be removed
by spraying the soil surface with asphalt emulsion and peeling off the resulting crust. When
the crust was mixed throughout the soil, as plowing would do, the strontium 90 eventually be came more available to barley plants. In another experiment, the crust wag mixed with the top
six inches of soil,.and the. soil was irrigated and planted to barley. At the tne of harvest,
ie tpt Missed nie eat 6 men dee wt nanos.
three months later, it was found that this treatment had effected a30 perceagt reduction in
strontium uptake2as compared with the untreated sou.
RADIOBIOLOGICAL SURVEYS OF THE MARSHALL ISLANDS AND WESTERN PACIFIC —
Radiobiological surveys have been made in the Marshall Islands since the initiation of the
Pacific testing program in 1946. In March 19 54 the fallout on several atollf in the Marshall
Islands, including Rongelap; was greater than had occurred ‘from previous fests... For this
reason surveys have been made frequently at Rongelap; there were 12 surfeys made between
March 1954 and July 1957. Determination of the amount of radioactivity arf of the radioisotopes
‘present has been madefor plants, animals, soils, and water. The results @f the findings of the