Plutonium inhalation

Chronic effects of plutonium exposure include lifeshortening and cancer. These effects have been observed in numerous animal studies. The main late pulmonary effects of plutonium inhalation are pulmonary fibrosis and lung cancer. Lung cancers in animals have been reported for intakes equivalent to 37kBq (1 pCi) in man. 

The isotope of plutonium inhaled will affect its behavior in the body. The bones and the liver are the primary organs for plutonium deposition following translocation in the body (ICRP 1982). However, Mclnroy et al. (1989) indicate that muscle tissue may also be a site of deposition. Plutonium-238 dioxide is more rapidly translocated from the lungs than plutonium-239 dioxide thereby causing more plutonium-238 to be concentrated in other body tissues (ICRP 1982). 

Individuals occupationally exposed to plutonium in the past are continually monitored in programs across the country. For example, whole body counting studies are currently conducted at Los Alamos National Laboratory in New Mexico. Animal studies conducted at the Lawrence Berkeley Laboratory, University of California, Berkeley, by P. Durbin are evaluating the behavior and movement of plutonium inhaled into the lungs. Models used to estimate body burden based on urinary excretion data and other biological measurements of plutonium (Leggett and Eckerman 1987) are under continual revision. 

BairW, McClanahan B. 1961. Plutonium inhalation studies. II. Excretion and translocation of inhaled Pu-23902 dust. Arch Environ Health 2 48-55. 

Bair W, Willard D. 1962. Plutonium inhalation studies. IV. Mortality in dogs after inhalation of Pu23902. Radiat Res 16 811-821. 

Clarke W, Bair W. 1964. Plutonium inhalation studies-VI. Pathologic effects of inhaled plutonium particles in dogs. Health Phys 10 391-398. 

Clarke W, ParkJ, Palotay J, et al. 1966. Plutonium inhalation studies-VII. Bronchiolo-alveolar carcinomas of the canine lung following plutonium particle inhalation. Health Phys 12 609- 613. 

Pu (86 years) is formed from Np. Pu is separated by selective oxidation and solvent extraction. The metal is formed by reduction of PuF with calcium there are six crystal forms. Pu is used in nuclear weapons and reactors Pu is used as a nuclear power source (e.g. in space exploration). The ionizing radiation of plutonium can be a health hazard if the material is inhaled. 

Elaborate precautions must be taken to prevent the entrance of Pu iato the worker s body by ingestion, inhalation, or entry through the skin, because all common Pu isotopes except for Pu ate a-emitters. Pu is a P-emitter, but it decays to Am, which emits both (X- and y-rays. Acute intake of Pu, from ingestion or a wound, thus mandates prompt and aggressive medical intervention to remove as much Pu as possible before it deposits in the body. Subcutaneous deposition of plutonium from a puncture wound has been effectively controlled by prompt surgical excision followed by prolonged intravenous chelation therapy with diethylenetriaminepentaacetate (Ca " —DTPA) (171). 

Plutonium has a much shorter half-life than uranium (24.000 years for Pu-239 6,500 years for Pu-240). Plutonium is most toxic if it is inhaled. The radioactive decay that plutonium undergoes (alpha decay) is of little external consequence, since the alpha particles are blocked by human skin and travel only a few inches. If inhaled, however, the soft tissue of the lungs will suffer an internal dose of radiation. Particles may also enter the blood stream and irradiate other parts of the body. The safest way to handle plutonium is in its plutonium dioxide (PuOj) form because PuOj is virtually insoluble inside the human body, gi eatly reducing the risk of internal contamination. 

Bioavailability from Environmental Media. The absorption and distribution of americium as a result of inhalation and ingestion exposures have been discussed in Sections 3.3.1 and 3.3.2. EPA lists identical uptake factors for inhaled and ingested americium (and all the other transuranics other than plutonium) regardless of compound solubility, indicating that the knowledge base for americium is not sufficiently developed to quantify the differences that are recognized for most other elements. 

Espinosa A, Aragon A, Stradling N, et al. 1998. Assessment of doses to adult members of the public in Palomares from inhalation of plutonium and americium. Radiat Prot Dosim 79(1-4) 161-164. 

Hammond SE, Lagerquist CR, Mann JR. 1968. Americium and plutonium urine excretion following acute inhalation exposure to high-fired oxides. Am Ind Hyg Assoc J 29(2) 169-172. 

Okabayashi H. 1980. Differential movement of plutonium and americium in lungs of rats following the inhalation of submicron plutonium nitrate aerosol. J Radiat Res 21 111-117. 

Stanley JA, Edison AF, Mewhinney JA, et al. 1978. Inhalation toxicology of industrial plutonium and uranium oxide aerosols II. Deposition, retention and dosimetry. Health Phys 35(6) 888. 

Stanley JA, Edison AF, Mewhinney JA. 1982. Distribution, retention and dosimetry of plutonium and americium in the rat, dog and monkey after inhalation of an industrial-mixed uranium and plutonium oxide aerosol. Health Phys 43(4) 521-530. 

Stradling GN, Stather JW, Gray SA, et al. 1994. Biokinetics of inhaled plutonium-239 and americium-241 present in contaminated dusts at Maralinga. Ann Occup Hyg 38(Suppl. l) 257-263. 

Bair, W. J., Richmond, C. R. and Wachholz, B. W. (1974). Radiological Assessment of the Spatial Distribution of Radiation Dose from Inhaled Plutonium, USAEC Report No. WASH-1320 (U.S. Atomic Energy Commission, Washington). 

Inhalation vs. oral Americium-241 Californium-252 Cesium-137 Cobalt-60 Hydrogen-3 Iodine-125 Iodine-129 Iodine-131 Phosphoms-32 Plutonium-239 Polonium-210 Radium-226 Strontium-90 Thorium-232 Uranium-235... 

On a comparative basis, Pu, Am and Cm tend to be assimilated from the G.I. tract into the internal body in the following order Pu < Am < Cm (Figure 3). When Pu-nitrate is inhaled in aerosol form by dogs (27), daughter Am-241 tends to be transported more from lung and lymph nodes to liver than does plutonium (Fig. 3). Another example of potential Am enrichment is that when the rumen contents of fistulated cattle grazing on the Nevada Nuclear Test Site were leached with simulated gastric fluids,... 

Figure 3. Enrichment of trivalent actinides over Pu(IV) across biological membranes. The assimilation of Am-241 and Cm-244 from the rat GI tract is greater than for plutonium. When plutonium nitrate is inhaled by dogs, daughter Am-241 is preferentially transported to the liver, resulting in depletion in lung and lymph nodes.

Pu(IV), which forms highly charged polymers, strongly sorbs to soils and sediments. Other actinide III and IV oxidation states also bind by ion exchange to clays. The uptake of these species by solids is in the same sequence as the order of hydrolysis Pu > Am(III) > U(VI) > Np(V). The uptake of these actinides by plants appears to be in the reverse order of hydrolysis Np(V) > U(VI) > Am(III) > Pu(IV), with plants showing little ability to assimilate the immobile hydrolyzed species. The further concentration of these species in the food chain with subsequent deposit in humans appears to be minor. Of the 4 tons of plutonium released to the environment in atmospheric testing of nuclear weapons, the total amount fixed in the world population is less than 1 g [of this amount, most (99.9%) was inhaled rather than ingested]. 

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