Data from several field studies of plutonium were evaluated to identify environmental factors that result in redistribution of this element within ecosystems.When released to terrestrial ecosystems, plutonium is almost quantitively transferred to and retained by soils. Thus, processes which transport soil within ecosystems predominate in the transport of environmental plutonium.Erosion of soils by wind and water is the principal means of translational movement of plutonium within terrestrial ecosystems. Soil erosion processes also dominate in the transport of soil plutonium to biological surfaces particularly in arid and semi-arid regions of the US.Understanding the relationships between soil erosional processes and plutonium transport within ecosystems is essential for prediction of plutonium fate and effects.
The translocation of high-fired PuOa via the lymphatic system from a simulated puncture wound in the left dorsal metacarpus of beagle dogs was studied. Comparisons were made between dogs with and without excision of the left superficial cervical lymph node. Accumulation of plutonium in the lymph node was determined by counting the low-energy X-ray complex with a thin NaI(T1) detector. The dogs were killed less than 2 weeks after implant and the activity determined for selected tissues. Higher levels of plutonium were found in the liver, spleen and hepatic lymph nodes of lymphadenectomized dogs than in the intact dogs. Implications of these data with regard to therapeutic lymph node removal for workers contaminated with plutonium are discussed.
Beagle dogs were given subcutaneous implants of plutonium in their forepaws to mimic hand wounds received by workers accidentally contaminated with plutonium. Ten dogs received 9.46 +/- 0.43 mu Ci of plutonium oxide, and eight dogs received 1.25 +/- 0.60 mu Ci of plutonium nitrate. Surviving dogs were sacrificed at 8 and 5 yr, respectively, after exposure, and radionanalyses were performed on the injection site, regional lymph nodes, liver, spleen and bone. Histopathologic and autoradiographic examinations were performed on injection sites, regional lymph nodes, livers, spleens, kidneys and grossly observed lesions. The injected paws sequestered 21 and 16%, respectively, of the injected activity from plutonium oxide and plutonium nitrate in hypocellular scar tissue. The highest concentrations of translocated radionuclides were found in the regional lymph nodes. Histopathologic and autoradiographic examinations of regional lymph nodes showed that the alpha activity was largely sequestered by scar tissue that replaced lymphoid parenchyma in the plutonium-oxide-injected dogs. In the plutonium-nitrate-injected dogs, activity was widely distributed in relatively intact regional lymph nodes. The liver had the next highest concentration for both radionuclides; activity was present as alpha stars. The spleen had the next highest concentration for plutonium-oxide-injected dogs, although concentrations in the spleen were lower than the skeleton in the plutonium-nitrate-injected dogs. Osteosarcomas and hepatomas were present in one dog injected with plutonium oxide. There does not appear to be any unique risk for dogs related to the subcutaneous route of exposure to plutonium.
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