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PubMed2003

Actinide analysis of a depleted uranium penetrator from a 1999 target site in southern Serbia.

Following the detection of 236U in depleted uranium (DU) ammunition used during the Balkans conflict in the 1990s, concern has been expressed about the possibility that other nuclides from the nuclear fuel cycle and, in particular, transuranium nuclides, might be present in this type of ammunition. In this paper, we report the results of uranium and plutonium analyses carried out on a depleted uranium penetrator recovered from a target site in southern Serbia. Our data show the depleted nature of the uranium and confirm the presence of trace amounts of plutonium in the penetrator. The activity concentration of (239+240)PU, at 45.4+/-0.7 Bq kg(-1), is the highest reported to date for any penetrator recovered from the Balkans. This concentration, however, is comparable to that expected to be present naturally in uranium ores and, from a radiological perspective, would only give rise to a very small increase in dose to exposed persons compared to that from the DU itself.

Environmental Exposure↗
PubMed1998

K-ras mutations in 239PuO2 canine lung neoplasms.

Single-strand conformational polymorphism (SSCP) analysis and direct sequencing methods were used to examine lung tumors derived from a cohort of beagle dogs with inhalational exposures to 239PuO2. These exposures were done at Pacific Northwest Laboratories where 18-month-old beagle dogs were given 239PuO2 by single-dose inhalation and allowed to live out their life-spans. Formalin-fixed paraffin-embedded blocks of tissues from 25 dogs exposed to 239PuO2 by aerosol inhalation which later developed lung tumors were available for this study. Two of 25 tumors had mutations within exon 1 of K-ras detected by SSCP analysis. Both mutations were GGT to GAT transitions at codon 12 confirmed by direct sequencing experiments. One was an adenocarcinoma from the medium-high exposure group and the other was a broncheolo-alveolar carcinoma from the medium-low exposure group. The rate of K-ras mutations in plutonium-induced lung tumors described herein (8%) was greater than previously described in canine plutonium-induced lung tumors (0%), but was less than that which we have described in spontaneous canine lung cancer (16%), less than that reported for human spontaneous non-small cell lung cancer (13-36%) and less than that described in rats with spontaneous lung cancer (40%) or lung tumors following 239Pu inhalation exposure (46%).

Administration, Inhalation↗
PubMedDate not supplied

Method for actinides and Sr-90 determination in urine samples.

The primary goal of radiation protection in decommissioning and decontamination of the old nuclear facilities of the CIEMAT is to monitor and minimize exposure of personnel. Monitoring programs include determination of actinides and 90Sr in biological samples. A technique for the sequential measurement of low levels of 239Pu, 241Am and 90Sr in urine samples has been developed. The method involves coprecipitation of these radionuclides as phosphates from bulk urine sample. Separation of Plutonium is carried out using a conventional anion exchange technique. Americium and strontium isolations are achieved sequentially by chromatographic extraction (Tru.Spec and Sr.Spec columns) from the load and rinse solutions coming from the anion exchange column. Plutonium and Americium measurements are performed by alpha spectrometry. The mean recovery obtained is 80% and the detection limit for 24 h urine sample (1.41) is 0.6 mBq L-1. 90Sr determination is made by liquid scintillation counting. The detection limit in this case is 1.1 E-01 Bq/L.

Actinoid Series Elements↗
PubMed1999

Distribution coefficients (Kd's) for use in risk assessment models of the Kara Sea.

As a prerequisite for most evaluations of radionuclide transport pathways in marine systems, it is necessary to obtain basic information on the sorption potential of contaminants onto particulate matter. Kd values for use in modeling radionuclide dispersion in the Kara Sea have been determined as part of several international programs addressing the problem of radioactive debris residing in Arctic Seas. Field and laboratory Kd experiments were conducted for the following radionuclides associated with nuclear waste: americium, europium, plutonium, cobalt, cesium and strontium. Emphasis has been placed on two regions in the Kara Sea: (i) the Novaya Zemlya Trough (NZT) and (ii) the mixing zones of the Ob and Yenisey Rivers (RMZ). Short-term batch Kd experiments were performed at-sea on ambient water column samples and on samples prepared both at-sea and in the laboratory by mixing filtered bottom water with small amounts of surficial bottom sediments (particle concentrations in samples = 1-30 mg/l). Within both regions, Kd values for individual radionuclides vary over two to three orders of magnitude. The relative particle affinities for radionuclides in the two regions are americium approximately equal to europium > plutonium > cobalt > cesium > strontium. The values determined in this study agree with minimum values given in the IAEA Technical Report [IAEA, 1985. Sediment Kd's and Concentration Factors for Radionuclides in the Marine Environment. Technical Report No. 247. International Atomic Energy Agency, Vienna.]. Given the importance of Kd's in assessments of critical transport pathways for radionuclide contaminants, we recommend that Kd ranges of values for specific elements rather than single mean values be incorporated into model simulations of radionuclide dispersion.

Americium↗
PubMed2005

Pu and U atom ratios and concentration factors in reservoir 11 and Asanov Swamp, Mayak PA: an application of accelerator mass spectrometry.

Mayak Production Association, East Ural, Russia, was established to produce weapons-grade plutonium. Routine discharges and accidents at Mayak PA contaminated large areas, including the Techa River. The objectives of the present work were to study atom ratios for plutonium and, for the first time to our knowledge, uranium isotopes in water, soil, grass, and aquatic biota samples from Reservoir 11 and the Asanov Swamp, downstream from Mayak PA. Atom ratios (240Pu/239Pu, 236U/235U, 235U/238U) were determined using accelerator mass spectrometry to confirm radionuclide source characteristics and calculate activities and concentration factors for the studied samples. The lowest 240Pu/239Pu atom ratios were consistently found in Asanov Swamp samples (approximately 0.019), indicating a major contribution from early discharges of weapons-grade Pu. 240Pu/239Pu atom ratios in Reservoir 11 were higher, indicating influence from more recent civil reprocessing. The presence of 236U is usually indicative of fuel irradiation; 236U/235U ratios increase from weapons to civil sources. Our new data show that Asanov samples had lower 236U/ 235U ratios than Reservoir 11 samples (0.0005-0.0045 for Asanov compared with 0.0074-0.0153 for Reservoir 11) in agreement with Pu results. Pu and U concentration factors calculated for vegetation and biota samples at Mayak were comparable with corresponding values found in the literature.

Environmental Monitoring↗
PubMed1993

Specific sequestering agents for the actinides. 21. Synthesis and initial biological testing of octadentate mixed catecholate-hydroxypyridinonate ligands.

The linear octadentate ligand 3,4,3-LIHOPO, which contains four 1-hydroxy-2(1H)-pyridinone (1,2-HOPO) groups, is the most effective agent for in vivo chelation of Pu(IV) yet prepared. However, its clinical potential is limited by acute toxicity of the free ligand (but not Fe3+ complex) at high dosage. The high acidity of HOPO ligands and the much lower acidity of catechol (CAM) ligands suggested that mixed octadentate (CAM-HOPO) ligands containing one or two 1,2-HOPO and three (or two) catechol (CAM) groups might be as effective for Pu removal [fully eight-coordinated Pu(IV) complexes formed at pH > or = 6] and less toxic than 3,4,3-LIHOPO. Treatment of spermine with 3-(2,3-dimethoxybenzoyl)thiazol-idine-2-thione (1) (molar ratio 2:1) gave 1,14-bis(2,3-dimethoxybenzoyl)-1,5,10,14-tetraazatetradecane (2, DiCAM-spermine) in 80% yield. Addition of 2 to a 2-fold excess of the reaction product of 1-hydroxy-2-pyridone-6-carboxylic acid (HOPO-C) and 1,1'-carbonyldiimidazole (CDI) in N,N-dimethylformamide (DMF) and deprotection with BBr3 gave 1,14-bis(2,3-dihydroxybenzoyl)-5,10-bis(1-hydroxy-2-pyridon-6-oyl) -1,5,10,14-tetraaza-tetradecane [3, 3,4,3-LI(diCAM-diHOPO)] in 5% yield. Addition of 2 to an equimolar amount of the reaction product of HOPO-C and CDI in N,N-dimethylacetamide (DMAA), purification of the hexadentate intermediate, subsequent treatment with an equimolar amount of 2,3-dimethoxybenzoyl chloride (DMB), and deprotection with BBr3 gave 1,5,14-tris(2,3-dihydroxybenzoyl)-10-(1-hydroxy-2-pyridon-6-oyl)-1 ,5,10,14- tetraazatetradecane [4, 3,4,3-LI(triCAM-HOPO)] in 5% yield. Ligands were administered to mice [30 mumol kg-1 ip at 1 h or orally at 3 min after iv injection of plutonium(IV)-238 citrate, kill at 24 h]. Plutonium excretion after injection of either CAM-HOPO ligand was 700% of that for 24-h Pu-injected controls, 140% of that for mice given the tetracatecholate analogue 3,4,3-LICAM (significantly more, p < 0.01), but only 80% of that promoted by 3,4,3-LIHOPO (significantly less). Orally administered 3,4,3-LI-(diCAM-diHOPO) promoted significantly more Pu excretion than an equimolar amount of CaNa3DTPA. Potency of the CAM-HOPO ligands for in vivo chelation of Pu(IV) resembled that of structurally hexadentate tris-(hydroxypyridinonate) and tris(sulfocatecholate) ligands and functionally hexadentate tetrakis-(sulfocatecholate) and tetrakis(carboxycatecholate) ligands. The Pu complexes of the CAM-HOPO ligands are to some degree unstable at pH < 7.4, as judged by Pu residues in kidneys in excess of 24-h Pu-injected controls. Synthetic yields were insufficient for chemical investigations or evaluation of acute toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)

Actinoid Series Elements↗
PubMed2003

Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha and gamma spectrometry.

The depth distribution of plutonium, americium, and 137Cs originating from the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of (239+240)Pu of 24-2400 Bq kg(-1) and specific activity of 241Am of 23-2000 Bq kg(-1), respectively. Transuranics in turf-podzol soil migrate slowly to the deeper soil layers, thus, 80-95%, of radionuclide inventories were present in the 0-3 cm intervals of turf-podzol soils collected in 1994. In peat-marsh soil migration processes occur more rapidly than in turf-podzol and the maximum concentrations are found beneath the soil surface (down to 3-6 cm). The depth distributions of Pu and Am are essentially identical for a given soil profile. (239+240)Pu/137Cs and 241Am/137Cs activity ratios vary by up to a factor of 5 at some sites while smaller variations in these ratios were observed at a site close to Chernobyl, suggesting that 137Cs is dominantly particle associated close to Chernobyl but volatile species of 137Cs are of relatively greater importance at the distant sites.

Americium↗
PubMed1970

The dynamics of life. I. Death from internal irradiation by 239Pu and 226Ra, aging, cancer, and other diseases.

Early in the era of atomic energy the potential of plutonium as an industrial and an environmental hazard was recognized. Thus, the Laboratory for Radiobiology was established at this University 20 years ago to compare the effects of plutonium and radium in beagles. Sufficient data have now accrued for exacting analysis. Concurrently we have formulated the steady-state theory of mutation rates which provides the necessary formalism to assess the survival data from the (239)Pu and (226)Ra study. Although the principal biological end point for both nuclides is the osteosarcoma, the mechanisms of nonsurvival for the two nuclides appear to be different. The success of the theory in this case suggests that application to data on irradiation of more inbred and more outbred species would prove to be exceedingly valuable.

Aging↗
PubMedDate not supplied

An investigation of the availability of 137Cs and 239 + 240Pu for gut absorption in winkles following cooking and in vitro simulated gastro-intestinal digestion.

The consumption of plutonium, americium and radiocaesium in locally collected shellfish is an important contributor to the radiation dose received by seafood consumers living in West Cumbria. Only a small fraction of the actinide activity is assumed to be absorbed via the gut whilst it is assumed that all the radiocaesium is. Solubilization studies reported here using an in vitro digestion method support the former assumption but not the latter, suggesting that the proportion of the 137Cs available for absorption could be significantly smaller than unity where a large percentage of the ingested Cs is adsorbed onto inorganic sedimentary material. Such a situation arises near the Sellafield nuclear-reprocessing plant where a high proportion of the radiocaesium (and plutonium) in the winkles collected locally and subsequently cooked is associated with inorganic particulate matter.

Biological Availability↗
PubMed1980

Comparative effects of protracted exposures to 60Co gamma-radiation and 239Pu alpha-radiation on breeding performance in female mice..

Breeding performances are compared of hybrid female mice given 239Pu (5 or 10 mu Cikg-1 body mass in 1% trisodium citrate via the tail-vein), or kept in a 10 rad/day or 20 rad/day 60Co gamma-irradiation field (but mated in the control area), or unirradiated. Ovarian dose-rates from the injected plutonium were initially 0.8 and 1.7 rad/day, changing little thereafter; actual gamma-ray dose-rates to breeding females averaged around 8 and 16 rad/day respectively. Both gamma-ray treatments affected reproductive performance more than the plutonium injections, with respet to duration of fertility and to offspring per litter in successive 4-weekly periods, though overall mean litter-sizes were not significantly less than controls. The r.b.e. for these effects on reproduction, attributed to germ-cell killing, is about 2.5 for the alpha-particles vs. gamma-rays, lower than for testis mass reduction in males. This low r.b.e. may be connected with inhomogeneity of alpha-particle dose within the ovary, but it is known that fission neutron versus gamma r.b.e.'s for impairment of female fertility are also lower than those for impairment of male fertility.

Alpha Particles↗
PubMed1988

SEM autoradiography: aggregation of inhaled 239PuO2.

Aggregation of inhaled 239PuO2 particles in the pulmonary region of the lung may be required for promotion of pulmonary carcinogenesis in rats. Female Wistar rats were exposed to an aerosol of 239PuO2 and their lungs examined by scanning electron microscopic (SEM) autoradiography. SEM autoradiography provides a rapid and inexpensive method for viewing a large lung tissue volume for alpha tracks. Evidence of particle aggregation was seen by 28 days postinhalation and was marked by 90 to 150 days post-inhalation. Subpleural plutonium particles resulted in exposure into the pleural cavity. Peribronchiolar, alveolar plutonium particles and particle aggregates gave the greatest radiation dose to the bronchiolar epithelium. High-dose, overlapping, alpha-track, radiation zones in bronchiolar epithelium may be required for maximum development of lung tumors.

Administration, Inhalation↗
PubMed1992

Incidence of brain tumours in rats exposed to an aerosol of 239PuO2.

Incidence of brain tumours was investigated in 3390 female and male Wistar rats exposed to an aerosol of 239PuO2, or as sham-exposed controls. Lung doses ranged from 0.05 to 22 Gy. In females, six brain tumours were found in 1058 control rats (incidence, 0.6%) and 24 brain tumours in 2134 rats exposed to Pu (incidence, 1.1%); the survival-adjusted level of significance was p = 0.29 for comparing control with exposed females. In males, two brain tumours were found in 60 control rats (incidence, 3.3%) and seven brain tumours in 138 rats exposed to Pu (incidence, 5.1%); the survival-adjusted level of significance was p = 0.33. Brain tumour incidence was about five times greater in male than in female rats (p = 0.0001), demonstrating a highly significant sex difference in brain tumour incidence. Tumour types were distributed similarly among control and Pu-exposed groups of both sexes; most tumours were astrocytomas. Mean lifespans for rats with brain tumours were not significantly different between control and Pu-exposed rats. Plutonium was not detected on autoradiograms of the brain. These results, like those for plutonium workers, show an increase of brain tumours which cannot be demonstrated statistically to be related to radiation exposure.

Administration, Inhalation↗
PubMed1987

Cancer incidence patterns in the Denver metropolitan area in relation to the Rocky Flats plant.

This study considered whether geographic patterns of cancer suggest any relation with Rocky Flats, a facility located near Denver, Colorado that processes plutonium components for nuclear weapons. The study was based upon cancer incidence data for the years 1969 to 1971 and 1979 to 1981, and census tract data for 1970 and 1980. Data for 1979 to 1981 showed little association with Rocky Flats, even though considerations of the timing of releases of radioactivity from the plant and cancer latency indicate that data from this period should be more indicative of an effect of Rocky Flats than data from the earlier period. The explanatory variable found to be most closely associated with cancer incidence was an urban factor measured by distance from the Colorado State Capitol located in downtown Denver. Indications of correlations of cancer incidence with proximity to Rocky Flats largely disappeared for both time periods when analyses were stratified by this urban factor. This negative finding was not surprising because persons living in the vicinity of the plant have been shown to have no more plutonium in their tissues than persons living in other areas of Colorado.

Colorado↗
PubMed2003

A computational study of the urinary excretion rates for 339Pu using new ICRP internal dosimetry models.

A computational study of the urinary excretion rates for 239Pu has been carried out using a methodology which involved the solution of a complete compartmental model describing the biokinetic behaviour of inhaled plutonium aerosols in the human body. The methodology, after proper validation, was applied to investigate the dependence of urinary excretion rates for 239Pu on the transfer rates given in the complete compartmental model. For this purpose, the default values of the transfer/absorption rates were modified by factors of 2 and 4 and urinary excretion rates were computed on 1, 10, 100, 1000 and 10,000 d post-intake. The percentage variations in the urinary excretion rates as a result of the modified transfer rates were computed for exposures to Type M and S aerosols of 239Pu. These results facilitated the identification of parameters significantly affecting the short-term and long-term urinary excretion rates. In addition, time variations of the predicted ratios of 239Pu activity in daily urine to that in blood (excretion ratios) were studied for the three biokinetic models of plutonium: the ICRP 67 model, the modified ICRP 67 model with the compartment STI to urinary bladder removed and Luciani and Polig's model. All the computational results are presented and discussed in this paper.

Air Pollution, Radioactive↗
PubMed2001

Bayesian prior probability distributions for internal dosimetry.

The problem of choosing a prior distribution for the Bayesian interpretation of measurements (specifically internal dosimetry measurements) is considered using a theoretical analysis and by examining historical tritium and plutonium urine bioassay data from Los Alamos. Two models for the prior probability distribution are proposed: (1) the log-normal distribution, when there is some additional information to determine the scale of the true result, and (2) the 'alpha' distribution (a simplified variant of the gamma distribution) when there is not. These models have been incorporated into version 3 of the Bayesian internal dosimetry code in use at Los Alamos (downloadable from our web site). Plutonium internal dosimetry at Los Alamos is now being done using prior probability distribution parameters determined self-consistently from population averages of Los Alamos data.

Bayes Theorem↗
PubMed2007

Uncertainties in doses calculated according to ICRP recommendations after inhalation of 239PUO2 and early chest monitoring.

This study estimates uncertainties in Pu biokinetics and effective doses calculated after an acute inhalation exposure to 239PuO2 according to ICRP recommendations (default values for aerosols size and PuO2 dissolution parameters). This was performed using the most recently reported variations in model parameters and simulations after a Monte Carlo approach. Without chest monitoring, uncertainties in thoracic retention and plutonium excretion was 8-10 (95% confidence interval as the ratio between 97.5 and 2.5 percentiles of the lognormal distributions) up to 900 d after exposure. Early chest monitoring reduces significantly the uncertainties in plutonium biokinetics and doses which remain within a 95% confidence interval of 2.3 as compared with 6.6, without monitoring. Analysis of bioassay data previously reported shows that the dose delivered to some individuals can be out of the confidence interval, which was mostly due to an inhibition of the late mechanical clearance of the alveolar interstitium.

Administration, Inhalation↗
PubMed1982

Further studies on the absorption of actinide elements from the gastrointestinal tract of neonatal animals.

Plutonium retention was measured after intragastric administration to neonatal rats, dogs and swine. At 1 week after administration, substantially more of the actinide remained in swine and dogs than in rats. The quantity of 238Pu absorbed by piglets was markedly influenced by such factors as compound solubility, mass of plutonium administered, oxidation state of the actinide, and age of the animal at gavage. Cortisone treatment reduced absorption, but was less effective in piglets than in neonatal rats. Measurements of 238Pu transport from ligated segments of the neonatal swine intestine indicated highest absorption from the duodenum, where the actinide was shown, autoradiographically, to be deposited in the epithelial region; in the ileum, deposition was predominantly in the lacteal region. Absorption of actinides by neonatal swine decreased in the order of 233U greater than 238Pu greater than 237Np greater than 244Cm greater than 241Am. Measurements at 1 yr after gavage showed a much higher retention by swine than by rats.

Actinoid Series Elements↗
PubMed1982

Repeated inhalation exposure of Beagle dogs to 239PuO2: retention and translocation.

Whole-body retention and distribution of 239Pu in selected tissues of Beagle dogs were determined after a series of two or four inhalation exposures to 239PuO2. Exposures were made at half-year intervals with alveolar depositions of about 150 nCi per exposure. Data are reported on dogs followed for one and two years after the first exposure. The plutonium was found to be extremely insoluble; 2-3% of the amount deposited in the alveolar region translocated to tracheobronchial lymph nodes and less than 0.1% translocated to other tissues. The whole-body retention, when compared to retention of 239Pu following a single exposure, supported the hypothesis that each exposure was retained independently with the same retention characteristics. This is in agreement with results reported by other investigators for one human repeatedly exposed by inhalation to low levels of aerosols containing plutonium-uranium fuels.

Aerosols↗