the animals were injected with americium, as opposed to plutonium;
nuclide retention in the liver was also greater for animals that had
received americium; a marked similarity existed in the nuclide deposition
pattern following ingestion of either Am-241 chloride or citrate-buffered
Pu-238 nitrate.
(Editor's note:
The acknowledgments paragraph of
Sutton’s report includes several additional EPA personnel who have
assisted in NAEG large animal studies, performed at the NTS experimental
farm.
Their assistance in these studies has been greatly appreciated by
the NAEG/Department of Energy.)
Americium-241 studies were also reported by J. Barth, EPA.
The alimentary
solubility and behavior of Am-241 were investigated in an artificial
rumen and simulated bovine gastrointestinal fluids.
Barth stated that
the data indicate that Am-241 administered as Am-241 nitrate solution
remains soluble in ruminant digestive fluids to considerable degree.
In
most digestive stages, the solubility of Pu-238 was greater than that of
Am-241, when both were in nitrate solution.
Barth discussed the results
with those of an EPA Am-241 metabolism study with dairy cows in order to
predict tissue retention and milk secretion of field-deposited Am-241
ingested by cattle grazing in Area 13 of the Nevada Test Site.
Data was presented by Smith, EPA, concerning the NAEG long-term grazing
Study with a reproducing beef herd on a plutonium-contaminated intensive
study site in Area 13, NTS.
Food habit analyses were discussed with
implications for relationships between actinide concentrations in the
ingesta and Eurotia lanata content.
Other interesting information reported by Smith related to the Pu-239 concentrations in bone, lung, and
liver collected from wildlife with free access to and from the plutoniuncontaminated study site.
Concentrations in bone, lung, and liver ranged
from 1 percent to 10 percent of those in the cattle confined to the
intensive study site.
A brief summary of the long-term study concluded
Smith's report.
Au and Beckert, EPA, presented results of a study to determine whether
plutonium associated with fungal tissue could be taken up by a successive
generation, or whether it becomes immobilized after metabolism by the
fungus.
Their results indicated that such transfer is possible to the
spores of new growth, using Aspergillus n. A summary was also included
concerning the previous NAEG microorganism studies of plutonium transport
in the NTS environment.
Plant uptake of Pu and Am through roots was investigated further by
Romney, Wallace, and Kinnear, UCLA, using NTS soils.
Their evaluation
of recent results indicated that vegetation-~to-soil concentration ratios
(C.R.) varied from 1075 to 1073 for 239°24 py, and from 107% to 107!
for 24 lam, depending on the type soil and agricultural amendments applied;
that generally Am was taken up by plants at a faster rate than Pu; that
DTPA chelate increased root uptake of both Pu and Am when added with
nitrogen, organic matter, or sulfur amendments; C.R. values were lower
for fruit than for vegetative parts of soybeans; Am was slightly more
available for transport from shoots to fruits of soybeans than Pu.
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