plutonium-dioxide and plutonium-nitrate

The Mayak Production Association (MPA) worker registry has shown evidence of plutonium-induced health effects. Workers were potentially exposed to plutonium nitrate [(239)Pu(NO(3))(4)] and plutonium dioxide ((239)PuO(2)). Studies of plutonium-induced health effects in animal models can complement human studies by providing more specific data than is possible in human observational studies. Lung, liver, and bone cancer mortality rate ratios in the MPA worker cohort were compared to those seen in beagle dogs, and models of the excess relative risk of lung, liver, and bone cancer mortality from the MPA worker cohort were applied to data from life-span studies of beagle dogs. The lung cancer mortality rate ratios in beagle dogs are similar to those seen in the MPA worker cohort. At cumulative doses less than 3 Gy, the liver cancer mortality rate ratios in the MPA worker cohort are statistically similar to those in beagle dogs. Bone cancer mortality only occurred in MPA workers with doses over 10 Gy. In dogs given (239)Pu, the adjusted excess relative risk of lung cancer mortality per Gy was 1.32 (95% CI 0.56-3.22). The liver cancer mortality adjusted excess relative risk per Gy was 55.3 (95% CI 23.0-133.1). The adjusted excess relative risk of bone cancer mortality per Gy(2) was 1,482 (95% CI 566.0-5686). Models of lung cancer mortality based on MPA worker data with additional covariates adequately described the beagle dog data, while the liver and bone cancer models were less successful.

Topics: Adolescent; Adult; Aged; Air Pollutants, Radioactive; Animals; Bone Neoplasms; Cohort Studies; Disease Models, Animal; Dogs; Dose-Response Relationship, Radiation; Female; Humans; Liver Neoplasms; Lung Neoplasms; Male; Middle Aged; Neoplasms, Radiation-Induced; Nitrates; Nuclear Reactors; Occupational Exposure; Plutonium; Radionuclide Generators; Registries; Risk Factors; Russia; Young Adult

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.

Topics: Animals; Dogs; Foot; Forelimb; Injections, Subcutaneous; Male; Neoplasms, Radiation-Induced; Nitrates; Plutonium; Radiation Injuries, Experimental; Time Factors; Tissue Distribution