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PubMed1996

Changes in soft tissue concentrations of plutonium and americium with time after human occupational exposure.

Concentrations of 239 + 240Pu and 241Am in human soft tissues (testes, thyroid gland, kidneys, spleen, heart, skeletal muscle, brain, and pancreas) were compared to those in livers of the same subjects. The subjects were volunteer donors with occupational exposures to plutonium and americium autopsied as part of the United States Transuranium and Uranium Registries program. The temporal distributions of tissue-to-liver ratios were compared to liver uptake fractions assumed on the basis of current models to estimate the initial uptake fractions for each tissue studied. Regressions of the ratios were used to compare tissue retention half-times to those of the liver. Effective half-times for plutonium and americium in the tissues studied were similar to those for the liver with three exceptions: (1) the clearance half-time for plutonium in kidneys is shorter than that of liver; (2) the retention half-time for plutonium in testes is longer than that of liver; and (3) the retention half-time for americium in skeletal muscle was longer than in the liver. Next to liver, the greatest initial uptake of systemic actinides was in skeletal muscle and the greatest initial concentrations were in the spleen. The uptake fraction of plutonium in the testes proposed by the ICRP was verified.

Americium↗
PubMed1996

Plutonium release from the 903 pad at Rocky Flats.

The Colorado Department of Public Health and Environment (CDH) sponsored a study to reconstruct contaminant doses to the public from operations at the Rocky Flats nuclear weapons plant. This analysis of the accidental release of plutonium from the area known as the 903 Pad is part of the CDH study. In the 1950's and 1960's, 55-gallon drums of waste oil contaminated with plutonium, and uranium were stored outdoors at the 903 Pad. The drums corroded, leaking contaminated oil onto soil subsequently carried off-site by the wind. The plutonium release is estimated using environmental data from the 1960's and 1970's and an atmospheric transport model for fugitive dust. The best estimate of total plutonium release to areas beyond plant-owned property is about 0.26 TBq (7 Ci). Off-site airborne concentrations and deposition of plutonium are estimated for dose calculation purposes. The best estimate of the highest predicted off-site effective dose is approximately 72 microSv (7.2 mrem).

Air Pollutants, Radioactive↗
PubMed2003

Rapid identification and analysis of airborne plutonium using a combination of alpha spectroscopy and inductively coupled plasma mass spectrometry.

Recent wildland fires near two U.S. nuclear facilities point to a need to rapidly identify the presence of airborne plutonium during incidents involving the potential release of radioactive materials. Laboratory turn-around times also need to be shortened for critical samples collected in the earliest stages of radiological emergencies. This note discusses preliminary investigations designed to address both these problems. The methods under review are same day high-resolution alpha spectroscopy to screen air filter samples for the presence of plutonium and inductively coupled plasma mass spectrometry to perform sensitive plutonium analyses. Thus far, using modified alpha spectroscopy techniques, it has been possible to reliably identify the approximately 5.2 MeV emission of 239Pu on surrogate samples (air filters artificially spiked with plutonium after collection) even though the primary alpha-particle emissions of plutonium are, as expected, superimposed against a natural alpha radiation background dominated by short-lived radon and thoron progeny (approximately 6-9 MeV). Several processing methods were tested to prepare samples for analysis and shorten laboratory turn-around time. The most promising technique was acid-leaching of air filter samples using a commercial open-vessel microwave digestion system. Samples prepared in this way were analyzed by both alpha spectroscopy (as a thin-layer iron hydroxide co-precipitate) and inductively coupled plasma mass spectrometry. The detection levels achieved for 239Pu--approximately 1 mBq m(-3) for alpha spectroscopy screening, and, < 0.1 mBq m(-3) for inductively coupled plasma mass spectrometry analysis--are consistent with derived emergency response levels based on EPA's Protective Action Guides, and samples can be evaluated in 36 to 72 h. Further, if samples can be returned to a fixed-laboratory and processed immediately, results from mass spectrometry could be available in as little as 24 h. When fully implemented, these techniques have the potential to provide useful information and improved operational flexibility to emergency planners and first-responders during radiological emergencies.

Air Pollution, Radioactive↗
PubMed1968

Phagocytosis of inhaled plutonium oxide-239pu particles by pulmonary macrophages.

Pulmonary macrophages and plutonium particles were removed by washing the lungs of rats that had inhaled plutonium oxide-(239)Pu. A significant amount of plutonium was found in multiple washings of the same lung. The removal of toxic particles by washing is of potential therapeutic value. Particles were phagocytized by macrophages during the first 3 hours and retained within these cells for up to 25 days. Nearly all particles in washings were found in macrophages after the second day. The percent of macrophages with engulfed particles increased with increasing amounts of plutonium deposited in the lungs. The ability of pulmonary macrophages to rapidly phagocytize and retain plutonium particles deposited in the lungs has been shown.

Aerosols↗
PubMed1969

Plutonium-238 in fallout.

The observed variation in the activity ratio of plutonium-238 to plutonium-239 plus plutonium-240 in rainwater in Japan over the period from 1961 through 1968 seems to indicate that the influence of the plutonium-238 released by the burnup of the nuclear auxiliary power generator (SNAP-9A) became noticeable within about 6 months and that variation in the isotope ratio with time is affected by nuclear debris produced in the latest explosions as well as by the plutonium-238 released from the SNAP-9A generator.

Explosions↗
PubMedDate not supplied

[Role of biocomponents of the bile and excreta in the elimination of plutonium and americium from the body].

A study was made of the role of biocomponents of bile, urine and feces in the elimination of plutonium and americium from the organism. Plutonium 239 and americium 241 were separated in bile due to higher tropism of plutonium to low molecular weight ligands, and of americium, to a protein-containing fraction. The status of plutonium excreted in feces was the same as the physicochemical status of americium. Plutonium 239 and americium 241 eliminated in urine were in a completely ultrafiltered state.

Americium↗
PubMed1984

Plutonium partitioning among internal organs.

An estimate of partitioning of plutonium among skeleton, liver, and other organs is needed to estimate the radiation dose to individual organs. This review was done to provide an analysis of the coefficients currently used for the translocation of plutonium from blood to other organs and excreta. Data from both experimental animals and human autopsy cases were used in our analysis. The analysis of data from 257 experimental animal and 169 human subjects led to a conclusion that a 70-30% split of plutonium distribution between skeleton and liver, respectively, would be appropriate for use in plutonium organ distribution models. Analysis of data from other organs and early excreta indicated that these other compartments generally comprised less than 3% of the total early body burden. The variability of plutonium distribution within all compartments is emphasized, with the conclusion that the coefficients of uptake to individual organs are adequate to estimate average organ doses for an exposed population but use for estimating doses for an individual will lead to uncertain results.

Animals↗
PubMed1981

Plutonium movements across the haemochorial placenta of the guinea pig.

In order to measure transplacental movements of plutonium without the complications of fetal accumulation, the fetal circulation of the guinea pig placenta (at 59 to 61 days of gestation) was perfused in situ. Dams were administered trace quantities of tritiated water (to indicate changes in maternal blood flow to the placenta) and 30 mu Ci/kg (i.e., approximately 500 micrograms/kg) of citrated 239Pu by intravenous injection. Plutonium-239 doses were large, approaching the LD50/30 (20 to 80 mu Ci/kg) for other species. Perfusion pressure, maternal cardiac rate, electrocardiogram, blood pressure, and respiratory rate were monitored continuously during each perfusion. Our measurements show that the clearance of plutonium from mother to fetus is small--2.5 +/- 0.5 microliter/min--an amount that is less than 20 per cent of the clearance of inorganic mercury. The indirect measurements of maternal blood flow to the placenta indicate that placental blood flow is greatly diminished in dams dosed with plutonium, which may partially account for the low clearance of plutonium.

Animals↗
PubMed1994

Plutonium-catalyzed oxidative DNA damage in the absence of significant alpha-particle decay.

Plutonium is considered to be a carcinogen because it emits alpha particles that may result in the irradiation of stem cell population. In the present study we show that plutonium can also catalyze reactions that induce hydroxyl radicals in the absence of significant alpha-particle irradiation. Using the low specific activity isotope, 242Pu, experiments were performed under conditions in which chemical generation of hydroxyl radicals was expected to exceed the radiolytic generation by one hundred thousand-fold. The results showed that markers of oxidative DNA base damage, thymine glycol and 8-oxoguanine could be induced from plutonium-catalyzed reactions of hydrogen peroxide and ascorbate similarly to those occurring in the presence of iron catalysts. Plutonium-242, as a neutralized nitrate in phosphate buffer, was 4.8-fold more efficient than iron at catalyzing the oxidation of ascorbate at pH 7. The results suggest that plutonium complexes could participate in reactions at pH 7 that induce oxidative stress--a significant tumor-promoting factor in generally accepted models of carcinogenesis.

Alpha Particles↗
PubMed2001

Correlated electrons in delta-plutonium within a dynamical mean-field picture.

Given the practical importance of metallic plutonium, there is considerable interest in understanding its fundamental properties. Plutonium undergoes a 25 per cent increase in volume when transformed from its alpha-phase (which is stable below 400 K) to the delta-phase (stable at around 600 K), an effect that is crucial for issues of long-term storage and disposal. It has long been suspected that this unique property is a consequence of the special location of plutonium in the periodic table, on the border between the light and heavy actinides-here, electron wave-particle duality (or itinerant versus localized behaviour) is important. This situation has resisted previous theoretical treatment. Here we report an electronic structure method, based on dynamical mean-field theory, that enables interpolation between the band-like and atomic-like behaviour of the electron. Our approach enables us to study the phase diagram of plutonium, by providing access to the energetics and one-electron spectra of strongly correlated systems. We explain the origin of the volume expansion between the alpha- and delta-phases, predict the existence of a strong quasiparticle peak near the Fermi level and give a new viewpoint on the physics of plutonium, in which the alpha- and delta-phases are on opposite sides of the interaction-driven localization-delocalization transition.

Journal Article↗
PubMed2006

FISH chromosome analysis of plutonium workers from the Sellafield nuclear facility.

Chromosome analysis using a single-color FISH technique to paint three pairs of chromosomes was undertaken on a group of 46 retired plutonium workers with assessed bone marrow doses >60 mSv, 34 of whom were categorized as having robust dosimetry and 12 for whom internal doses were considered less reliable. Comparisons were made with a group of 34 workers with negligible radiation exposure and a group of 34 workers with similar recorded external gamma-ray doses but negligible internal dose. The simple translocation frequency of 17.65 +/- 1.96 x 10(-3) per genome equivalent for the 34 plutonium workers with robust dosimetry was significantly increased in comparison with that of 10.06 +/- 1.16 x 10(-3) per genome equivalent for the unirradiated control group (P = <0.001) and that of 13.55 +/- 1.43 x 10(-3) per genome equivalent for the group with similar external gamma-ray exposure (P = 0.012). Thus, although in vitro studies have indicated that the majority of alpha-particle-irradiated cells suffer complex non-transmissible chromosome damage, in vivo a significant proportion survive with simple exchanges that can be passed on to descendant cells. In contrast, the three groups demonstrated no significant differences in stable complex aberrations. No evidence of an increase in dicentrics or unstable complex aberrations associated with plutonium exposure was observed, and it can therefore be assumed that there is little, if any, ongoing irradiation of mature lymphocytes. The translocation frequency of 12.08 +/- 1.92 x 10(-3) per genome equivalent for the group of 12 plutonium workers with less reliable internal dosimetry could adequately be accounted for by age and external dose and indicates that the internal bone marrow doses are likely to have been overestimated. Cytogenetic analysis can therefore make a valuable contribution to the validation of internal doses from plutonium deposition.

Aged↗
PubMed2004

Separation of plutonium from uranium using reactive chemistry in a bandpass reaction cell of an inductively coupled plasma mass spectrometer.

Oxygen and ammonia were evaluated as reaction gases for the chemical separation between uranium and plutonium in the bandpass reaction cell or dynamic reaction cell (DRC) of the ELAN DRC II mass spectrometer. Both uranium and plutonium demonstrated similar reactivity with oxygen giving rise to corresponding oxides. At the same time, remarkable selectivity in the reaction with ammonia was observed. While uranium was rapidly converted into UNH 2+ and UN2H 4+, plutonium remained unreactive in the DRC pressurized with ammonia. This difference in the reactivity allowed the determination of plutonium isotopes in urine and water samples containing excess uranium without preceding separation procedure. Detection limits of 0.245, 0.092, 0.270 and 0.237 ng L(-1) were obtained for 238Pu, 239Pu, 240Pu and 242Pu, respectively, in urine spiked with 10 microg L(-1) of U.

Ammonia↗
PubMed1989

The distribution of 137Cs, plutonium and Americium in sheep.

Radiochemical measurements on tissues taken from sheep from the Cumbrian and Lancashire coast have given data which allow the tissue distribution and body content of plutonium isotopes, americium-241 and caesium-137 to be calculated. The data are particularly useful as the concentrations in lung confirm that for these animals the main route of intake is from the diet and not from inhalation. Plutonium and americium concentrate in the liver and skeleton. Caesium-137 was, as expected, found mainly in the meat of the animals. Additionally a controlled feeding experiment has been conducted to determine the gastrointestinal absorption of plutonium and americium from contaminated vegetation. A value of 0.01% for plutonium and 0.005% for americium was determined.

Americium↗
PubMed1990

Transfer of environmental plutonium and americium across the human gut: a second study.

A follow-up to our previous study is described on human gut transfer factors for plutonium and americium in winkles harvested from the shoreline near the British Nuclear Fuels plc Sellafield reprocessing plant. Six male and two female adult volunteers ate single quantities of shellfish; samples of their urine before and after consumption were analysed. As in the previous study, the plutonium and americium excreted were difficult to detect, and counting times of approximately 8 weeks were employed. Results are presented in detail to allow further interpretation, but preliminary assessment has been carried out on the basis of published data for excretion following transfer to blood. The mean and range obtained for the gut transfer for plutonium was 1.3 (0.2-3.2) x 10(-4); for americium the result was 0.8 (0.4-1.7) x 10(-4). Combined with the results of the previous study when interpreted on the same basis, the results were 1.7 (0.2-4.9) x 10(-4) and 0.9 (0.3-2.8) x 10(-4), respectively. No significant evidence was revealed in this study for differences in gut transfer between males and females, nor for seasonal differences, e.g. due to differences in form of incorporation of actinides in shellfish. For realistic assessments of doses due to shellfish consumption near Sellafield, to assess compliance with criteria recommended by the International Commission on Radiological Protection (ICRP), a suitable value for the gut transfer factor of both plutonium and americium might be 2 x 10(-4). A value of 5 x 10(-4) would appear to be cautious.

Adult↗
PubMed1986

Determination of plutonium in feces and urine.

A method was developed for the determination of plutonium (239Pu, 238Pu, etc.) in feces and urine excreted by persons for 24 h. Plutonium is successively separated from inorganic macrocomponents present in samples and from other alpha emitters by the help of coprecipitation with BiPO4, LaF3 and extraction with TTA. After separation, the electrodeposition of plutonium on stainless-steel discs can be carried out. The chemical yields of separation of plutonium are about 80%.

Feces↗
PubMedDate not supplied

Geochemical fractionation of plutonium in anoxic Irish Sea sediments using an optimised sequential extraction protocol.

An optimised five-step sequential extraction protocol, incorporating the use of sodium citrate to inhibit resorption, has been used to assess the solid partition of plutonium under anoxic conditions in intertidal sediments from the Ravenglass Estuary in the north-eastern Irish Sea. The data reveal that the plutonium is predominantly bound to geochemical phases targeted by the acido-soluble and the exchangeable extractants, indicating that a significant proportion of the plutonium in these and similar sediments is associated with relatively mobile geochemical phases. The results are consistent with the relatively high level of plutonium remobilisation now known to be taking place throughout the north-eastern Irish Sea.

Algorithms↗
PubMed2006

Plutonium isotopes derived from Nagasaki atomic bomb in the sediment of Nishiyama reservoir at Nagasaki, Japan.

The source of plutonium in sediments deposited at Nishiyama reservoir at Nagasaki was characterized by their (240)Pu/(239)Pu atom ratio. The average ratio was approximately 0.03, except in two layers. The main source of the plutonium was the Nagasaki atomic bomb. The plutonium continues to flow into the reservoir even now. The (240)Pu/(239)Pu atom ratios in two layers were higher than the average, which showed that plutonium in these layers were made of those of nuclear tests added to those of the atomic bomb.

Cesium Radioisotopes↗
PubMed2003

Concentrations of plutonium and americium in plankton from the western Mediterranean Sea.

Understanding the transfer of radionuclides through the food chain leading to man and in particular, the uptake of transuranic nuclides by plankton, is basic to assess the potential radiological risk of the consumption of marine products by man. The main sources of transuranic elements in the Mediterranean Sea in the past were global fallout and the Palomares accident, although at present smaller amounts are released from nuclear establishments in the northwestern region. Plankton from the western Mediterranean Sea was collected and analyzed for plutonium and americium in order to study their biological uptake. The microplankton fractions accounted for approximately 50% of the total plutonium contents in particulate form. At Garrucha (Palomares area), microplankton showed much higher 239,240 Pu activity, indicating the contamination with plutonium from the bottom sediments. Concentration factors were within the range of the values recommended by the International Atomic Energy Agency. Continental shelf mesoplankton was observed to efficiently concentrate transuranics. In open seawaters, concentrations were much lower. We speculate that sediments might play a role in the transfer of transuranics to mesoplankton in coastal waters, although we cannot discard that the difference in species composition may also play a role. In Palomares, both 239,240 Pu and 241Am showed activities five times higher than the mean values observed in continental shelf mesoplankton. As the plutonium isotopic ratios in the contaminated sample were similar to those found in material related to the accident, the contamination was attributed to bomb debris from the Palomares accident. Concentration factors in mesoplankton were also in relatively good agreement with the ranges recommended by IAEA. In the Palomares station the highest concentration factor was observed in the sample that showed predominance of the dynoflagellate Ceratium spp. Mean values of the enrichment factors showed, on average, discrimination rather than enrichment in the primary producer trophic chain.

Americium↗