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PubMed1988

Plutonium and americium uptake in rats fed with Cumbrian shellfish--implications for estimates of dose to man.

Winkles (Littorina littorea) and mussels (Mytilus edulis) collected on the Cumbrian coast contain americium-241 and isotopes of plutonium discharged from the nuclear-fuel reprocessing plant at Sellafield. Shellfish have been fed to rats and measurements made of the gastrointestinal absorption of the actinides. For shellfish collected over a 1-year period from March 1983 to February 1984, the average values for the fractional absorption of plutonium and americium were 9 x 10(-4) and 3 x 10(-4), respectively, for winkles and 1.5 x 10(-3) and 6 x 10(-4), respectively, for mussels. Comparisons with results for winkles collected in December 1981 and mussels collected in July 1982 suggest that there may be considerable seasonal variation in the availability of the actinides for absorption. The results suggest that in calculations of doses to individuals consuming shellfish in west Cumbria, it may be prudent to examine the effect of using the new ICRP gut transfer factor of 1 x 10(-3) for both actinides, in comparison with the value of 5 x 10(-4) recommended previously by NRPB. The use of 1 x 10(-3) would increase the estimate of the committed effective dose equivalent for 1985 intakes, from the value of 0.73 mSv calculated by the Ministry of Agriculture, Fisheries and Food, to 1.29 mSv. However, taking into account up-to-date estimates of the retention of the actinides in liver and bone would reduce this value to 1.07 mSv. If, in addition, allowance is made for the effect of the burial and recycling of actinides in bone, a significant reduction in the dose estimate could result; for example, the use of one proposed dynamic bone model would reduce the value from 1.07 to 0.54 mSv.

Americium↗
PubMed1989

The biodistribution and toxicity of plutonium, americium and neptunium.

In the nuclear fuel cycle the transuranic radionuclides plutonium-239, americium-241 and neptunium-237 would probably present the most serious hazard to human health if released into the environment. Despite differences in their solution chemistry the three elements exhibit remarkable similarity in their biochemical behaviour, apparently sharing similar transport pathways in blood and cells. After entering the blood the elements deposit predominantly in liver and skeleton, where retention appears to be prolonged, with half-times of the order of years. The principal late effects of all three radionuclides are the induction of cancers of bone, lung or liver. For the latter tumours the induction risk per unit radiation dose appears similar for the three radionuclides. But in bone there are indications that, due to microscopic differences in the distribution of the alpha-particle radiation dose, the efficiency of bone cancer induction may increase in the order americium-241 less than plutonium-239 less than neptunium-237. No case of human cancer induced by these radionuclides is known.

Americium↗
PubMed1984

Computer simulation of metal ion equilibria in biofluids. IV. Plutonium speciation in human blood plasma and chelation therapy using polyaminopolycarboxylic acids.

An investigation by computer simulation into the nature of Pu(IV) binding to low-molecular ligands in human blood plasma is described. Particular consideration is given to the interactions of various chelating agents which have been or might be used for treating plutonium intoxication. Formation constants of EDTA and DTPA with Cu(II), Mg(II), Mn(II), Zn(II), and Cd(II) have been measured under biologic conditions of temperature and background electrolyte. The relative ability of these and other chelating agents to cause excretion of plutonium and the concomitant loss of certain essential trace metals has thus been assessed.

Chelating Agents↗
PubMed1995

Assessment of plutonium exposures in Rongelap and Utirik populations by fission track analysis of urine.

A nuclear device, code-named Bravo, detonated at Bikini Atoll at 6:45 a.m. on 1 March 1954, unexpectedly released a large amount of radioactivity. Over 40 years after this incident, the study of its impact on the radiological health and environmental safety of the residents of Rongelap and Utirik Atolls continues. In 1987, researchers at Brookhaven National Laboratory established a fission track analysis (FTA) method for low-level 239Pu urinalysis. Two years later, a new shipboard protocol was developed for collecting 24-h radiologically clean urine samples. The purpose of this paper is to update information on the FTA method for measuring low-levels of plutonium, and to summarize results on the distribution of 239Pu in the populations of Rongelap and Utirik between 1981-1991. Plutonium detection levels (99% confidence level) in these samples were 2-3 microBq, which is equivalent to 0.2-0.3 mSv effective dose equivalent (EDE) to age 70 for Marshallese. The latest 1991 FTA data indicate average EDE of 0.62 mSv and 1.6 mSv for the people of Rongelap and Utirik, respectively, which both are the highest values since 1988.

Adolescent↗
PubMed2005

Determination of plutonium in environmental samples by AMS and alpha spectrometry.

Environmental samples from nuclear weapons test sites at the atolls of Mururoa and Fangataufa (French Polynesia, south Pacific) have been analyzed for their content of plutonium isotopes by applying the independent techniques of decay counting (Alpha Spectrometry) and accelerator mass spectrometry (AMS). Here, we propose the combination of both techniques which results in a maximum of information on the isotopic signature of Pu in environmental samples. Plutonium was chemically separated from the bulk material by anion exchange. (242)Pu was used as an internal standard for both AMS and alpha spectrometry. The samples for alpha spectrometry were prepared by micro-precipitation with NdF(3). After alpha spectrometry, the samples were reprocessed for AMS. Pu was co-precipitated with Fe(OH)(3) and finally, solid samples were prepared. At the VERA (Vienna Environmental Research Accelerator) facility, the various Pu isotopes were separated by their isotopic masses and quantified by the AMS technique. A good agreement of the results obtained from the AMS measurements was found with those obtained from Alpha Spectrometry. Overall, the data agree on average within 10% of each other. Isotope ratios for (238)Pu, (239)Pu and (240)Pu can be extracted from our investigations. Alpha spectrometry delivers data for the (238)Pu and the combination of ((239+240))Pu concentrations in those samples. In addition, the AMS technique provides information on the individual concentrations of (240)Pu and (239)Pu.

Alpha Particles↗
PubMed2004

Wet and dry deposition patterns of plutonium in Daejeon, Korea.

Plutonium in wet and dry deposition samples collected monthly at the Korea Institute of Nuclear Safety (KINS), Daejeon, Korea was determined during the period from January 2000 to August 2000. Monthly 239,240Pu deposition in Korea showed a maximum in the spring season (March to May), which was several times greater than that in Japan and corresponds to a seasonal cycle of soil dust fallout originating from the East Asian arid areas. The trajectory analysis of dust storms suggests that 239,240Pu deposition in Korea in spring is originating from plutonium-bearing surface soil particles from the East Asian arid areas. A significant part of the 239,240Pu deposition in spring in Korea is attributable to dry deposition.

Air Movements↗
PubMed2001

Assessment of the global fallout of plutonium isotopes and americium-241 in the soil of the central region of Saudi Arabia.

A radiochemical technique for determination of plutonium isotopes and 241Am in soil samples is tested against IAEA-standard reference materials to determine its accuracy and precision for reliable results. The technique is then used in the investigation of topsoil samples, collected from the natural environment of the central region of Saudi Arabia, to assess the effect of fallout accumulation of these radionuclides in the region. Plutonium and americium were sequentially separated from all other components of the sample by anion-exchange chromatography and co-precipitated with Nd3+ as fluorides. The precipitates were mounted on membrane filters and measured using a high-resolution alpha-spectrometer. The results of the analysis of the reference materials showed satisfactory sensitivity and precision of the technique. The results of the analyzed soil samples show activity levels ranging from < LLD to 0.089 and from <LLD to 0.50 Bq/kg for 238Pu and 239+240Pu, respectively. 241Am levels ranged from <LLD to 0.49 Bq/kg. 238Pu/239+240Pu and 241Am/239+240Pu activity ratios ranged from 0 to 0.216 and 0.3-1.23, respectively. A discussion based on the observed data is presented.

Americium↗
PubMed2003

Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo.

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, (239 + 240)Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, (239 + 240)Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U)). The results indicated that whenever the U concentration exceeded the normal environmental values (approximately 2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg) = 2.6 x 10(-5), indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/(239 + 240)Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).

Environmental Monitoring↗
PubMed2002

Comparative uptake of plutonium from soils by Brassica juncea and Helianthus annuus.

Plutonium uptake by Brassica juncea (Indian mustard) and Helianthus annuus (sunflower) from soils with varying chemical composition and contaminated with Pu complexes (Pu-nitrate [239Pu(NO3)4], Pu-citrate [239Pu(C6H5O7)], and Pu-diethylenetriaminepentaacetic acid (Pu-DTPA [239Pu-C14H23O10N3]) was investigated. Sequential extraction of soils incubated with applied Pu was used to determine the distribution of Pu in the various soil fractions. The initial Pu activity levels in soils were 44.40-231.25 Bq g(-1) as Pu-nitrate Pu-citrate, or Pu-DTPA. A difference in Pu uptake between treatments of Pu-nitrate and Pu-citrate without chelating agent was observed only with Indian mustard in acidic Crowley soil. The uptake of Pu by plants was increased with increasing DTPA rates, however, the Pu concentration of plants was not proportionally increased with increasing application rate of Pu to soil. Plutonium uptake from Pu-DTPA was significantly higher from the acid Crowley soil than from the calcareous Weswood soil. The uptake of Pu from the soils was higher in Indian mustard than in sunflower. Sequential extraction of Pu showed that the ion-exchangeable Pu fraction in soils was dramatically increased with DTPA treatment and decreased with time of incubation. Extractability of Pu in all fractions was not different when Pu-nitrate and Pu-citrate were applied to the same soil. More Pu was associated with the residual Pu fraction without DTPA application. Consistent trends with time of incubation for other fractions were not apparent. The ion-exchangeable fraction, assumed as plant-available Pu, was significantly higher in acid soil compared with calcareous soil with or without DTPA treatment. When the calcareous soil was treated with DTPA, the ion-exchangeable Pu was comparatively less influenced. This fraction in the soil was more affected with time of incubation. The lowest extractable Pu was from a pH 6.55 Crockett soil that contained the highest clay compared to the other two soils. Extractable soil Pu was largely affected by soil pH and the amounts of clay, salt, metal oxide, and carbonate.

Biodegradation, Environmental↗
PubMedDate not supplied

Plutonium and other alpha-emitters in bones of wild, herbivorous animals from north-eastern Poland.

The results of the investigation of (239+240)Pu, 241Am and thorium isotope activity concentrations in bones of wild herbivorous animals (deer, roe-deer, boars, elks) from north-eastern Poland are presented. The area on which the animals were living had relatively high Chernobyl plutonium fallout. Possible traces of plutonium were seen only in four samples, but only for one it was it 3sigma above background, at 6.2 +/- 2.4 mBq/kg (ash). The 241Am activity concentration was below the detection limits in all samples. The maximum 228Th concentration in the samples was 7.81 +/- 0.44 Bq/kg (ash), calculated under the assumption of 100% thorium recovery. This isotope seems to originate in bones not from direct incorporation but from the decay of 228Ra. Large variations in activity concentration wose observed, as well as some differences between boars and the chewing animals.

Americium↗
PubMed2006

Electrochemically modulated separation, concentration, and detection of plutonium using an anodized glassy carbon electrode and inductively coupled plasma mass spectrometry.

Plutonium is shown to be retained on anodized glassy carbon (GC) electrodes at potentials positive of +0.7 V (vs Ag/AgCl reference) and released upon potential shifts to values negative of +0.3 V. This phenomenon has been exploited for the separation, concentration, and detection of plutonium by the coupling an electrochemical flow cell on-line with an ICPMS system. The electrochemically controlled deposition and analysis of Pu improves detection limits by analyte preconcentration and by matrix and isobaric ion elimination. Information related to the parametric optimization of the technique and hypotheses regarding the mechanism of electrochemical accumulation of Pu are reported. The most likely accumulation scenario involves complexation of Pu(IV) species, produced under a controlled potential, with anions retained in the anodization film that develops during the activation of the GC electrode. The release mechanism is believed to result from the reduction of Pu(IV) in the anion complex to Pu(III), which has a lower tendency to form complexes.

Carbon↗
PubMed2005

Structural characterization of the first hydroxo-bridged plutonium compound, (PuO(2))(2)(IO(3))(mu(2)-OH)(3).

The hydrothermal reaction of a (239)Pu(IV) stock solution in the presence of iodic acid and 1 M KOH produces reddish-brown single crystals of (PuO(2))(2)(IO(3))(OH)(3). The structure consists of two-dimensional layers forming in the ac plane and is the first single-crystal structure of plutonium(VI) connected through hydroxide anions. The additional linkage of plutonium centers is completed through iodate ligands.

Crystallography, X-Ray↗
PubMed1995

Specific sequestering agents for the actinides. 28. Synthesis and initial evaluation of multidentate 4-carbamoyl-3-hydroxyl-1-methyl-2(1H)-pyridinone ligands for in vivo plutonium(IV) chelation.

A new family of chelating agents based on 4-(substituted-carbamoyl)-3-hydroxy-2-pyridinones is reported. These have optional terminal substituents on the nitrogens, and the hydroxypyridonate (HOPO) rings are attached to molecular backbones through amide linkages. A very important feature of the methyl-substituted ligand derivatives (Me-3,2-HOPOs) is that, similarly to the catechoylamide complexes of the siderophore enterobactin and its analogs, these HOPO derivatives form strong hydrogen bonds between the amide proton and the adjacent oxygen of the phenolate in the metal complex; this enhances the stability of the complex. This rigidity helps to explain the great affinity of the Me-3,2-HOPO ligands for plutonium(IV), as observed here under physiological conditions. All 13 compounds studied significantly enhanced Pu excretion from mice compared with Pu-injected controls. Eight of the ligands studied promoted significantly more Pu excretion than an equal molar amount of CaNa3-DTPA (the compound in present clinical use). Five injected and two orally administered Me-3,2-HOPO ligands promoted as much or slightly more Pu excretion than an equal molar amount of the octadentate 3,4,3-LI(1,2-HOPO), the previously most effective in vivo ligand. Surprisingly, although plutonium has an eight-coordination requirement, tetra- and hexadentate Me-3,2-HOPO ligands were essentially as effective as the one octadentate ligand studied. These observations suggest that even the tetradentate Me-3,2-HOPO ligands compete with mammalian transferrin for Pu(IV). For the three most promising compounds, there is no acute toxicity seen up to the highest dose administered, which was 1000 mumol/kg. One compound, the hexadentate TREN-(Me-3,2-HOPO), is particularly effective, either injected or orally, and an exceptionally good in vivo chelator of several actinides in addition to Pu(IV). Three of these compounds studied have low toxicity and are relatively simple and inexpensive to prepare. They are promising therapeutic agents.

Administration, Oral↗
PubMed1997

The World War II plutonium experiments: contested stories and their lessons for medical research and informed consent.

During the Second World War medical researchers around the USA injected 18 hospital patients with radioactive plutonium in order to learn its effects on the body. Two documents, a newspaper account and a university committee report, tell divergent stories of the scientists and patients involved in that experiment. This article uses those documents-plutonium narratives-as a catalyst for exploring the problematic representation of past human experimentation, assumptions of moral progress in medical research, and the nature of informed consent today. Informed consent is shown to be an evolving process and discursive practice that cannot be understood apart from its historical and cultural embeddedness.

Bone Neoplasms↗
PubMed1976

Hazards of plutonium with special reference to the skeleton.

In the past attempts have been made to deduce plutonium toxicity in man from studies based on animal experimentation. An alternative method is to use the comparative dosimetry of plutonium and radium in man, with results broadly in agreement with maximum permissible levels set by the International Commission of Radiological Protection.

Animals↗
PubMed1976

Aspects of the dosimetry of plutonium in bone.

After animals have been exposed to plutonium it eventually becomes distributed unevenly throughout the bone tissue. There is therefore a need to study the dosimetry of plutonium, particularly 239Pu, as a function of its depth of burial in bone. This article discusses a simple approach to the problem, and the magnitude of some of the possible errors involved.

Animals↗
PubMedDate not supplied

Plutonium redistribution by biological activity in Irish Sea sediments.

As part of a programme investigating the fate of transuranium nuclides discharged to coastal waters we have studied the effects of benthic animals on plutonium redistribution in Irish Sea sediments. From analyses of burrow linings of the large echiuroid Maxmulleria lankesteri, which penetrates to depths exceeding 40 cm, we now show that this animal may have a significant effect on the removal of plutonium to deeper layers in the sea bed.

Invertebrates↗
PubMed2004

Oxidation of plutonium dioxide.

The physics and chemistry of the actinide elements form the scientific basis for rational handling of nuclear materials. In recent experiments, most unexpectedly, plutonium dioxide has been found to react with water to form higher oxides up to PuO(2.27), whereas PuO(2) had always been thought to be the highest stable oxide of plutonium. We perform a theoretical analysis of this complicated situation on the basis of total energies calculated within density functional theory combined with well-established thermodynamic data. The reactions of PuO(2) with either O(2) or H(2)O to form PuO(2+delta) are calculated to be endothermic: that is, in order to occur they require a supply of energy. However, our calculations show that PuO(2+delta) can be formed, as an intermediate product, by reactions with the products of radiolysis of water, such as H(2)O(2).

Models, Chemical↗