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In 2008, Serandour et al. reported on their in vitro experiment involving rat plasma samples obtained after an intravenous intake of plutonium citrate. Different amounts of DTPA were added to the plasma samples and the percentage of low-molecular-weight plutonium measured. Only when the DTPA dosage was three orders of magnitude greater than the recommended 30 μmol/kg was 100% of the plutonium apparently in the form of chelate. These data were modeled assuming three competing chemical reactions with other molecules that bind with plutonium. Here, time-dependent second-order kinetics of these reactions are calculated, intended eventually to become part of a complete biokinetic model of DTPA action on actinides in laboratory animals or humans. The probability distribution of the ratio of stability constants for the reactants was calculated using Markov Chain Monte Carlo. These calculations substantiate that the inclusion of more reactions is needed in order to be in agreement with known stability constants. [ABSTRACT FROM AUTHOR]

The distribution of calculated internal doses has been determined for 8043 Mayak Production Associate (Mayak PA) workers. This is a subset of the entire cohort of 25 757 workers, for whom monitoring data are available. Statistical characteristics of point estimates of accumulated doses to 17 different tissues and organs and the uncertainty ranges were calculated. Under the MWDS-2013 dosimetry system, the mean accumulated lung dose was 185 ± 594 mGy (geometric mean = 28 mGy; geometric standard deviation = 9.32; median value = 31 mGy; maximum value = 8980 mGy). The ranges of relative standard uncertainty were from 40 to 2200% for accumulated lung dose, from 25-90% to 2600-3000% for accumulated dose to different regions of respiratory tract, from 13-22% to 2300-2500% for systemic organs and tissues. The Mayak PA workers accumulated internal plutonium lung dose is shown to be close to log normal. The accumulated internal plutonium dose to systemic organs was close to a log triangle. The dependency of uncertainty of accumulated absorbed lung and liver doses on the dose estimates itself is also shown. The accumulated absorbed doses to lung, alveolar-interstitial region, liver, bone surface cells and red bone marrow calculated both with MWDS-2013 and MWDS-2008 have been compared. In general, the accumulated lung doses increased by a factor of 1.8 in median value, while the accumulated doses to systemic organs decreased by factor of 1.3-1.4 in median value. For the cases with identical initial data, accumulated lung doses increased by a factor of 2.1 in median value, while accumulated doses to systemic organs decreased by 8-13% in median value. For the cases with both identical initial data and all of plutonium activity in urine measurements above the decision threshold, accumulated lung doses increased by a factor of 2.7 in median value, while accumulated doses to systemic organs increased by 6-12% in median value. [ABSTRACT FROM AUTHOR]

In order to check developed software tools, it was necessary to compare estimates of statistical characteristics of annual absorbed plutonium internal doses obtained by PANDORA and IMBA software with the same original data. The results were compared from dose calculations of five cases with different initial data on plutonium inhalation intake, lifetime measurements of plutonium activity in daily urine and post-mortem measurements in lungs, lung lymph nodes, liver and skeleton. Estimates of geometric mean and geometric standard deviation of annual regionally weighted lung dose and bone surface dose were compared. Satisfactory agreements of the estimates of statistical characteristics of annual doses to two critical organs for the selected cases were shown. One hundred individual hyper-realizations (forward model evaluations) are sufficient to calculate MWDS-2013 if only measurements of plutonium activity in daily urine are used, and 2000 individual hyper-realizations if both urine and autopsy measurement results are used. [ABSTRACT FROM AUTHOR]

The calculation of reliable and realistic doses for use in epidemiological studies for the quantification of risk from internal exposure to radioactive material is fundamental to the development of advice, guidance and regulations for the control and use of radioactive material. Thus, any programme of work carried out which requires the calculation of doses for use by epidemiologists ideally should contain a rigorous program of quality assurance (QA). This paper describes the initial QA (Phase I) implemented by Public Health England (PHE) and the Southern Urals Biophysics Institute (SUBI) as part of the work programme on internal dosimetry in the Joint Coordinating Committee for Radiation Effects Research Project 2.4 for the 2013 Mayak Worker Dosimetry System. SUBI designed and implemented new software (PANDORA) to include the latest Mayak Worker Dosimetry System and to calculate organ burdens, urinary excretion rates, intakes and absorbed doses, while PHE modified their commercially available IMBA Professional Plus software package. Comparisons of output from the two codes for the Mayak Worker Dosimetry System 2013 showed calculated values of absorbed doses, intakes, organ burdens and urinary excretion agreed to within 1%. The 1% discrepancy can be explained by the approximation used in IMBA to speed up dose calculations. [ABSTRACT FROM AUTHOR]

Different dose estimates have been produced for the Mayak PA workforce over recent years (DOSES-2000, DOSES-2005, MWDS-2008). The dosimetry system MWDS-2013 described here differs from previous analyses, in that it deals directly with uncertainty in the assumed model parameters. This paper details the way in which uncertainty is dealt with within MWDS-2013 to produce the final output represented by a multiple hyper-realisation of organ doses. More specifically, the paper describes: • Application of the WeLMoS method to calculate Bayesian posterior probability distributions of organ doses. • Extension of the WeLMoS method for dealing with multiple intake regimes. • How shared and unshared parameters are dealt with using a multiple realisation method. • A practical algorithm for the generation of multiple hyper-realisations. • How to deal with uncertainty in the intake and the intake regime. The resulting multiple hyper-realisation contains all of the information required to take account of model parameter uncertainty and the effects of shared and unshared parameters in any epidemiological analysis, which uses this information, although it is acknowledged that in practice, certain data simplifications may be required to make such analyses tractable, and comparable to previous analyses. Such simplifications are outside the scope of this paper. [ABSTRACT FROM AUTHOR]

A method to estimate plutonium content from a limited number of samples of lungs and pulmonary lymph nodes obtained at autopsies of former Mayak Production Association (MPA) workers is described. Historically from one to five samples of lung lobes and one to three respiratory lymph nodes (bronchopulmonary, tracheobronchial and paratracheal) were collected. The samples were used to estimate organ plutonium contents for cases where incomplete sets of samples were obtained, i.e. one to four lung lobes and one to two lymph nodes. This method was developed and validated using individual measurement data from 259 MPA autopsy cases with complete lung samples (five lobes) and three lymph nodes. A good correlation of plutonium content in measurements of two and four lung samples with the content estimate by five lung samples was obtained. The correlations with the individual lymph nodes were less robust than with the lung. The data are used to develop biokinetic, dosimetry and risk models for humans exposed to plutonium. [ABSTRACT FROM AUTHOR]

The method to estimate total skeleton plutonium burden of former Mayak Production Association (MPA) workers from limited bone samples obtained at autopsy is described. From two to nine bone samples were obtained at autopsies conducted from the mid-1950s to 2013. Plutonium was measured using alpha-radiometry up to 2000 and later by alpha-spectrometry. The method was validated using data from whole-body donations from the United States Transuranium and Uranium Registries (USTUR). The developed algorithm overestimated the USTUR values from 20 to 40%, that is quite acceptable for conservative estimation. Late-in-life liver diseases known to redistribute plutonium between liver and skeleton were not associated with significant differences in plutonium deposition among sampled bones, except for the pelvis. Sources of uncertainties are discussed and future studies will address the reduction of these uncertainties. This algorithm can be used to obtain data in support of the development of biokinetic, dosimetric and risk models for humans exposed to plutonium. [ABSTRACT FROM AUTHOR]

In the Mayak Worker Dosimetry System (MWDS-2013), intakes of plutonium and organ doses are assessed on the basis of measurements made on the plutonium content of 56 400 urine samples. Altogether, there were urine bioassays for 7591 (29%) of the 25 757 cohort members who were employed any time at Mayak between 1948 and 1982. These measurements are subject to uncertainty due to many factors (e.g. whether or not creatinine is measured, the volume of the sample, whether diethylenetriamine-pentaacetic acid was administered, etc.) and this uncertainty will affect not only the uncertainty in the estimated doses, but also the values of the doses themselves. Therefore, it is important for the estimated uncertainty to be as accurate as possible. The input to the dose calculation requires an estimate of the plutonium activity in a true 24-hour sample. The uncertainty in this activity is approximated by a lognormal distribution. The aim of this paper is to describe and justify how the parameters of this lognormal distribution are derived from the raw data. Histograms of the distribution of sample volumes are given for both sexes. The method of calculation of the decision threshold and relative standard uncertainty (RSU) of a measurement result for Pu activity in a worker's urine sample is shown. Diagrams of correlation between Pu activity in collected urine and its RSU are given. [ABSTRACT FROM AUTHOR]

Previous Mayak worker epidemiological studies designed to quantify the risk of cancer following exposure to airborne plutonium have calculated organ doses by dividing the organ-absorbed energy by the individual's estimated organ mass. For living workers, this was done by using a relationship between organ mass and total mass and height. For autopsy cases, this was measured directly. In the Mayak Worker Dosimetry System-2013 study, organ doses are calculated by dividing this energy by a population average organ mass. The reasons for departing from previous methodologies are described in this note. The average organ masses that were used in the final analysis are tabulated for males and females. [ABSTRACT FROM AUTHOR]

The Mayak Worker Dosimetry System-2013 (MWDS-2013) uses a model developed by Leggett and colleagues to represent the biokinetic behaviour of plutonium after uptake to blood. Of particular importance, with regard to estimating intakes (and doses), is the distribution of activity between urine and body organs (particularly liver and skeleton). In this study, measurement data (urine and autopsy) from around 500 Mayak workers have been used to validate use of this model. A robust method has been developed and used to estimate intakes from both urine and autopsy data separately, and the ratio of these estimates has been calculated for each worker. The geometric mean ratio has been shown to lie within a range of 0.92-1.14, depending on assumptions made. Since this range includes 1, the hypothesis that the model is unbiased with regard to estimating intakes either with urine or autopsy data cannot be rejected on the basis of these data. This lends weight to the argument for increasing the MWDS-2013 cohort to include an additional 500 workers for whom only autopsy data are available, and who have previously been excluded from the cohort. Future directions in which this work could be extended are also suggested. [ABSTRACT FROM AUTHOR]

In order to estimate doses of workers exposed to plutonium, it is necessary to make assumptions about both the route and the time course of intake. The objective of this study was to determine a time course for the inhalation rate for plutonium (intake regime) useful for biokinetic modeling. Records from workplace air sampling, personnel biophysical examinations and autopsy data from former Mayak Production Association (MPA) workers were used. Plutonium accumulation strongly correlated with the volumetric activity of plutonium in workplace air. Using data from activity in air at MPA workplaces over time, a three-step function of intake was adopted. The adequacy of this three-step function was tested by comparing predicted doses using more complicated intake regimes. Uncertainties on the three-step function were also characterized based on air sampling data. The three-step function was assumed to be common to all workers, but an individual intake regime for each worker was calculated by convoluting it with the worker's actual employment history. [ABSTRACT FROM AUTHOR]

Lung doses resulting from inhalation of plutonium aerosols are highly dependent on the assumed rate of particle clearance, which occurs by two competing processes: (1) particle transport clearance to the alimentary tract and to the thoracic lymph nodes and (2) clearance to systemic tissues, which occurs by dissolution of particles in lung fluid followed by uptake to blood, which is a process collectively known as absorption. Unbiased and accurate estimates of the values of lung absorption parameters are required to obtain reliable estimates of lung dose, particularly those inferred from urine bioassay. Parameter values governing the rate of absorption are best estimated from data, such as autopsy measurements of plutonium in the lungs and systemic tissues, which directly relate to the exposed workers of interest. However, because the mathematical models that determine clearance from the lungs and systemic tissues are complex and consist of many parameters, estimates of model parameter values are subject to significant uncertainties. With this in mind, this paper uses a Bayesian approach to estimate one of the most important dissolution parameters: the slow rate of dissolution. This is estimated for both plutonium nitrate and plutonium oxide bearing aerosols in the lungs of former workers of the Mayak Production Association. A value of 2.6 × 10-4 d-1 is estimated for plutonium nitrates, and 4.7 × 10-5 d-1 for plutonium oxides. [ABSTRACT FROM AUTHOR]

Estimates of plutonium lung doses from urine bioassay are highly dependent on the rate of absorption from the lungs to blood assumed for the inhaled aerosol. Absorption occurs by dissolution of particles in lung fluid followed by uptake to blood. The latter may occur either rapidly or dissolved ions may first become temporarily bound within airway tissue. The presence of long-term binding can greatly increase lung doses, particularly if it occurs in the bronchial and bronchiolar regions. Analyses of autopsy data from Beagle dogs and USTUR Case 0269, obtained following exposure to plutonium nitrate, suggest that a small fraction of 0.2-1.1 and 0.4-0.7%, respectively, of plutonium becomes permanently bound within the lungs. The present work performs a further analysis using autopsy data of former plutonium workers of the Mayak Production Association to determine values of the bound fraction that are supported by these data. The results suggest a bound fraction value of 0-0.3%. The results also indicate that the Mayak worker population median values of the particle transport clearance parameters from the alveolar-interstitial region are largely consistent with expected values, but suggest the rate from the alveolar region to the interstitium may be lower than initially thought. [ABSTRACT FROM AUTHOR]

Radionuclides in ionic form can become chemically bound in the airways of the lungs following dissolution of inhaled particulates in lung fluid. The presence of long-term binding can greatly increase lung doses from inhaled plutonium, particularly if it occurs in the bronchial and bronchiolar regions. However, the only published evidence that plutonium binding occurs in humans comes from an analysis of the autopsy and bioassay data of United States Transuranium and Uranium Registries Case 0269, a plutonium worker who experienced a very high (58 kBq) acute inhalation of plutonium nitrate. This analysis suggested a bound fraction of around 8 %, inferred from an unexpectedly low ratio of estimated total thoracic lymph node activity:total lung activity, at the time of death. However, there are some limitations with this study, the most significant being that measurements of the regional distribution of plutonium activity in the lungs, which provide more direct evidence of binding, were not available when the analysis was performed. The present work describes the analysis of new data, which includes measurements of plutonium activity in the alveolar-interstitial (AI) region, bronchial (BB) and bronchiolar (bb) regions, and extra-thoracic (ET) regions, at the time of death. A Bayesian approach is used that accounts for uncertainties in model parameter values, including particle transport clearance, which were not considered in the original analysis. The results indicate that a long-term bound fraction between 0.4 and 0.7 % is required to explain this data, largely because plutonium activity is present in the extra-thoracic (ET2), bronchial and bronchiolar airways at the time of death. [ABSTRACT FROM AUTHOR]

For the first time, plutonium retention in human upper airways was investigated based on the dosimetric structure of the human respiratory tract proposed by the International Commission on Radiological Protection (ICRP). This paper describes analytical work methodology, case selection criteria, and summarizes findings on soluble (ICRP 68 Type M material) plutonium distribution in the lungs of a former nuclear worker occupationally exposed to plutonium nitrate [239Pu(NO3)4]. Thirty-eight years post-intake, plutonium was found to be uniformly distributed between bronchial (BB), bronchiolar (bb) and alveolar-interstitial (AI) dosimetric compartments as well as between the left and right lungs. 239+240Pu and 238Pu total body activity was estimated to be 2333 ± 23 and 42.1 ± 0.7 Bq, respectively. The results of this work provide key information on the extent of plutonium binding in the upper airways of the human respiratory tract. [ABSTRACT FROM AUTHOR]

The revised human respiratory tract model, published in Part 1 of the International Commission on Radiological Protection's (ICRP) report on Occupational Intakes of Radionuclides (OIR), includes a bound fraction, fb, to represent radionuclides that have become chemically bound in the lungs following dissolution of particulates in lung fluid. Bound radionuclides are not subject to particle transport clearance but can be absorbed to blood at a rate, sb. The occurrence of long-term binding of plutonium can greatly increase lung doses, particularly if it occurs in the bronchial and bronchiolar regions. However, there has been little evidence that currently supports the existence of a long-term bound state for plutonium. The present work describes the analysis of measurements of lung data obtained from a life span study of Beagle dogs that were exposed by inhalation to different concentrations of plutonium-239 (239Pu) nitrate aerosol at Pacific Northwest Laboratories, USA. The data have been analysed to assess whether a bound state was required to explain the data. A Bayesian approach was adopted for the analysis that accounts for uncertainties in model parameter values, including uncertainties in the rates of particle transport clearance. Furthermore, it performs the analysis using two different modelling hypotheses: a model based on the current ICRP human respiratory tract model and its treatment of alveolar particle transport clearance; and a model of particle transport clearance that is based on the updated model developed by ICRP to calculate dose coefficients for the OIR. The current model better represents clearance in dogs at early times (up to 1 year following intake) and the latter better represents retention at greater times (>5 years following intake). The results indicate that a long-term bound fraction of between 0.16 and 1.1%, with a mean value of between 0.24 and 0.8% (depending on the model) is required to explain the data. [ABSTRACT FROM AUTHOR]

The Mayak Worker Dosimetry System (MWDS-2013) is a system for interpreting measurement data from Mayak workers from both internal and external sources. This paper is concerned with the calculation of annual organ doses for Mayak workers exposed to plutonium aerosols, where the measurement data consists mainly of activity of plutonium in urine samples. The system utilises the latest biokinetic and dosimetric models, and unlike its predecessors, takes explicit account of uncertainties in both the measurement data and model parameters. The aim of this paper is to describe the complete MWDS-2013 system (including model parameter values and their uncertainties) and the methodology used (including all the relevant equations) and the assumptions made. Where necessary, Supplementary papers which justify specific assumptions are cited. [ABSTRACT FROM AUTHOR]

The reconstruction of radiation doses to Mayak Production Association workers in central Russia supports radiation epidemiological studies for the U.S.-Russian Joint Coordinating Committee on Radiation Effects Research. The most recent version of the dosimetry was performed with the Mayak Worker Dosimetry System-2013. This introduction outlines the logic and general content of the series of articles presented in this issue of Radiation Protection Dosimetry. The articles summarize the models, describe the basis for most of the key decisions made in developing the models and present an overview of the results. [ABSTRACT FROM AUTHOR]

This paper describes the use of IBC′s AnaLigPu-02 molecular recognition technology product to effectively and selectively pre-concentrate, separate and recover plutonium from urine samples. This method uses two-stage column separations consisting of two different commercial products, Eichrom's Pre-filter Material and AnaLigPu-02 resin from IBC Advanced Technologies. By eliminating the co-precipitation techniques and the ashing steps to remove residual organics, the analysis time was reduced significantly. The method was successfully tested by adding known activities of reference solutions of Pu and Pu to urine samples. [ABSTRACT FROM AUTHOR]

An analytical method was developed for simultaneous determination of ultratrace level plutonium (Pu) and neptunium (Np) using iron hydroxide coprecipitation in combination with automated sequential injection extraction chromatography separation and accelerator mass spectrometry (AMS) measurement. Several experimental parameters affecting the analytical performance were investigated and compared including sample preboiling operation, aging time, amount of coprecipitating reagent, reagent for pH adjustment, sedimentation time, and organic matter decomposition approach. The overall analytical results show that preboiling and aging are important for obtaining high chemical yields for both Pu and Np, which is possibly related to the aggregation and adsorption behavior of organic substances contained in urine. Although the optimal condition for Np and Pu simultaneous determination requires 5-day aging time, an immediate coprecipitation without preboiling and aging could also provide fairly satisfactory chemical yields for both Np and Pu (50-60%) with high sample throughput (4 h/sample). Within the developed method, 242Pu was exploited as chemical yield tracer for both Pu and Np isotopes. 242Pu was also used as a spike in the AMS measurement for quantification of 239Pu and 237Np concentrations. The results show that, under the optimal experimental condition, the chemical yields of 237Np and 242Pu are nearly identical, indicating the high feasibility of 242Pu as a nonisotopic tracer for 237Np determination in real urine samples. The analytical method was validated by analysis of a number of urine samples spiked with different levels of 237Np and 239Pu. The measured values of 237Np and 239Pu by AMS exhibit good agreement (R² ≥ 0.955) with the spiked ones confirming the reliability of the proposed method. [ABSTRACT FROM AUTHOR]

A novel bead injection (BI) extraction chromatographic microflow system exploiting a high-capacity lab-on-valve (LOV) platform coupled with inductively coupled plasma mass spectrometric detection is developed for rapid and automated determination of plutonium in human urine. A column attached to the LOV processing unit is loaded online with a metered amount of disposable extraction chromatographic resin (up to 330 mg of TEVA (abbreviation for tetravalent actinides)) through programmable beads transport. Selective capture and purification of plutonium onto the resin beads is then performed by pressure driven flow after preliminary sample pretreatment. The analytical results demonstrate the large capacity of bead surfaces for uptake of Pu within the tailor-made LOV platform that fosters processing of large-sized biological samples, e.g., 1 L of human urine, along with good reproducibility for automatic column renewal (0.319 ± 0.004 g, n = 5). The chemical yields of plutonium were averagely better than 90% under the optimal experimental conditions, and the entire analytical procedure could be accomplished within a short time frame (<3 h) as compared to manual counterparts (1-2 days). Therefore, the developed system is well suited for expedient analysis of low-level plutonium in urine of exposed individuals as required in emergency situations. [ABSTRACT FROM AUTHOR]

Studies of health effects in animals after exposure to internally deposited radionuclides were intended to supplement observational studies in humans. Both nuclear workers and Beagle dogs have exhibited plutonium-associated lung fibrosis; however, the dogs' smaller gene pool may limit the applicability of findings to humans. Data on Beagles that inhaled either plutonium-238 dioxide (238PuO2) or plutonium-239 dioxide (239PuO2) were analyzed. Wright's Coefficient of Inbreeding was used to measure genetic or familial susceptibility and was assessed as an explanatory variable when modeling the association between lung fibrosis incidence and plutonium exposure. Lung fibrosis was diagnosed in approximately 80%% of the exposed dogs compared with 23.7%% of the control dogs. The maximum degree of inbreeding was 9.4%%. Regardless of isotope, the addition of inbreeding significantly improved the model in female dogs but not in males. In female dogs, an increased inbreeding coefficient predicted decreased hazard of a lung fibrosis diagnosis. Lung fibrosis was common in these dogs with inbreeding affecting models of lung fibrosis incidence in females but not in males. The apparent protective effect in females predicted by these models of lung fibrosis incidence is likely to be minimal given the small degree of inbreeding in these groups. [ABSTRACT FROM AUTHOR]

Purpose: To study the cellular responses to molecular and polymeric forms of plutonium using PC12 cells derived from a rat pheochromocytoma. Materials and methods: Serum starved PC12 cells were exposed to polymeric and molecular forms of plutonium for 3 h. Cells were washed with 10 mM ethylene glycol tetraacetic acid (EGTA), 100 mM NaCl at pH 7.4 to remove surface sorbed plutonium. Localization of plutonium in individual cell was quantitatively analyzed by synchrotron X-ray fluorescence (XRF) microscopy. Results: Molecular plutonium complexes introduced to cell growth media in the form of nitrilotriacetic acid (NTA), citrate, or transferrin complexes were taken up by PC12 cells, and mostly colocalized with iron within the cells. Aged polymeric plutonium prepared separately was not internalized by PC12 cells but it was always found on the cell surface as big agglomerates; however, polymeric plutonium formed in situ was mostly found within the cells as agglomerates. Conclusions: PC12 cells can differentiate molecular and polymeric forms of plutonium. Molecular plutonium is taken up by PC12 cells and mostly co-localizes with iron but aged polymeric plutonium is not internalized by the cells. [ABSTRACT FROM AUTHOR]

In a recent epidemiological study, Bayesian uncertainties on lung doses have been calculated to determine lung cancer risk from occupational exposures to plutonium. These calculations used a revised version of the Human Respiratory Tract Model (HRTM) published by the ICRP. In addition to the Bayesian analyses, which give probability distributions of doses, point estimates of doses (single estimates without uncertainty) were also provided for that study using the existing HRTM as it is described in ICRP Publication 66; these are to be used in a preliminary analysis of risk. To infer the differences between the point estimates and Bayesian uncertainty analyses, this paper applies the methodology to former workers of the United Kingdom Atomic Energy Authority (UKAEA), who constituted a subset of the study cohort. The resulting probability distributions of lung doses are compared with the point estimates obtained for each worker. It is shown that mean posterior lung doses are around two- to fourfold higher than point estimates and that uncertainties on doses vary over a wide range, greater than two orders of magnitude for some lung tissues. In addition, we demonstrate that uncertainties on the parameter values, rather than the model structure, are largely responsible for these effects. Of these it appears to be the parameters describing absorption from the lungs to blood that have the greatest impact on estimates of lung doses from urine bioassay. Therefore, accurate determination of the chemical form of inhaled plutonium and the absorption parameter values for these materials is important for obtaining reliable estimates of lung doses and hence risk from occupational exposures to plutonium. [ABSTRACT FROM AUTHOR]

The article discusses a study on the finger wound contaminated by plutonium in a nuclear plant worker of the Mayak Production Association in Russia. The worker is treated with a ten-day therapy of calcium sodium diethylene triamine pentaacetic acid, in conjunction with in vivo measurements of the wound and urine bioassays. The amount of radionuclides is consistent with the radioactive materials that are excised from the wound.

The article discusses a study on the application of chelation therapy on three cases of finger wounds contaminated by 239Pu at the Los Alamos National Laboratory in New Mexico. The injections contain one gram of either trisodium calcium diethylenetriaminepentaacetate of trisodium zinc diethylenetriaminepentaacetate. The tissue and urine samples including wound measurement are taken from each of the subjects to assess the efficacy of the treatment.

The article discusses a study on uncertainties in the periodic monitoring of workers in the plutonium purification division of Areva NC in La Hague, France. The sources of uncertainties are the time of contamination, absorption of the particles in the blood and errors in the measurement. The Bayesian probability distribution model and sensitivity analysis that are used for monitoring the workers reduce the uncertainties depending on the dose.

The article offers information on the 24-year follow-up on a wound in the right index finger of a worker at the Hanford Site Plutonium Recovery Facility that occurred in 1985. One week after the accident, surgery is performed on the wound and chelation therapy is administered. An annual bioassay is performed which monitored the activity of 241Am at the wound site and in the skeleton. The excretion of plutonium in the urine is also monitored. The annual physical examination has not detected any adverse effect of the plutonium intake.

The article describes a physiological skeletal model (PSM) that represents the biokinetic behavior of radionuclides and stable elements. The PSM is used to determine risk to cancer of children and infants due to the contamination of their bones by plutonium and lead. The biokinetic parameters of the PSM is evaluated in adults.

The article reports on a study which determined the microdistribution of plutonium in bone tissues taken from a former worker of the Mayak Production Association in Ozyorsk, Russia. The exposure, medical and occupational history of the worker was obtained, in addition to the plutonium level in his organs. An autoradiography was performed to detect plutonium in the fission tracks. The plutonium decays in bone volume and bone surface did not conform to the bone fraction recommended by the International Commission on Radiological Protection.

The article focuses on a study which determined the low-level plutonium activity in human tissue samples obtained from bone, lungs, kidneys and liver, using sector-field high resolution inductively coupled plasma-mass spectrometry. The human tissues utilized were collected from areas around the Semipalatinsk Nuclear Test Site (SNTS) from 1949 to 1989. In an effort to identify the health effects of plutonium, the isotropic ratio of separated and purified, and plutonium isotopes (240Pu/239Pu) were measured. The materials and methods, and results of the study are highlighted.

This article discusses radiation dosimetry estimates from the Mayak plutonium production facility in the former Soviet Union. The authors describe the updated dosimetry uncertainties and error in the models used for dose reconstruction of absorbed organ doses from archives of worker exposure history, film dosimeter, and Monte Carlo techniques for calculated dose conversion factors. Plutonium intake was estimated using empirical based on bioassay and autopsy cases and radiological protection models. Additional uncertainties were determined for dose estimates resulting from changes in the smoking toggle and the transportability classification.

A worker provided a routine faecal sample for plutonium and americium analysis. In the course of this analysis 500 mBq of 228Th was discovered. There seemed no credible occupational route for intake of thorium. Further investigation revealed that the worker consumed ~25 g d-1 of nuts, including Brazil nuts. A sample of these nuts was analysed and found to contain activities of 228Th in sufficient quantity to account for the faecal activity. However, follow-up urine samples taken from the worker showed 0.6-0.7 mBq of 228Th. The intake of 228Th via nuts is insufficient to account for this activity in urine. However, it is likely that the intake of 228Th was accompanied by similar activity of the parent 228Ra, and biokinetic calculations show that decay of 228Ra in vivo would produce sufficient 228Th to account for the observed urine activity. [ABSTRACT FROM AUTHOR]

The article presents information regarding the experiment on the systemic distribution of americium in the beagle dogs. The experiment model was developed measuring the excreted radio activity and organ burdens for different levels of initial injected activity. The adopted parameters in developing the plutonium model was the compartmental structure of the skeleton. In the experiment, only the numerical values of parameters were adapted and the model described the fractions of americium in the skeleton, liver and soft tissues and the total fraction excreted in urine and feces. A realistic description of the change in the partitioning between liver and skeleton for different injection levels was provided by different parameters. The important features of the biokinetics and dosimetry of americium and plutonium in beagles are compared and found that in case of plutonium the total fractions of the clearance to the skeleton and the liver are roughly equal to the value of it. But in case of americium the partitioning between these organs is reversed with respect to the partitioning of plutonium.

This paper summarizes the systemic organ distribution of plutonium in workers exposed by chronic inhalation at the Mayak Production Association (MPA). Using results of radiochemical measurements in soft tissue and bone samples collected at autopsy of 853 autopsy cases, this paper provides data on the effects of various chronic diseases and malignant tumors as well as exposure time, age, sex, and body burden on systemic retention of plutonium in 22 extrapulmonary organs and on the urinary excretion rate of the nuclide. Some aspects of this work have been reported already. The results of present autopsy studies showed that liver pathology accompanied by strong fatty dystrophy of hepatocytes results in a significant relative decrease in the fraction of systemic plutonium in the liver and contravariant increase in the skeletal fraction. The average fractions of systemic plutonium in the liver and the skeleton of those MPA workers were 15% and 75%, respectively, in comparison with 47% and 45% in healthy individuals. Some of the plutonium also redistributed from the liver via blood to other systemic soft tissues. Plutonium not redistributed was excreted with urine. The results of multivariate regression analysis indicated some time-related and sex- related changes not connected with pathology for the liver and the skeleton retention fractions and excretion rate of plutonium. The current ICRP biokinetic models do not account for the influence of different pathological processes in the body on plutonium distribution in systemic organs and urinary excretion. This could have significant consequences for dosimetry calculations and risk estimations. [ABSTRACT FROM AUTHOR]

Abstract Human thyroid carcinomas have been induced following exposure of SV40-immortalized human thyroid epithelial cells in vitro to single doses (0.14 Gy to 1.57 Gy) of 3.26 MeV alphaparticles from a plutonium 238 source. Tumours were detected between 50 and 160 days following subcutaneous transplantation of the irradiated cells in athymic mice. No tumours were observed following transplantation of unirradiated cells. The relative biological effectiveness (RBE) of the alpha-particles, estimated from cell survival curves, was 4.8 at 50% survival and 3.3 at 5% survival. A first estimate of the RBE at peak tumour induction was 3.8. This system provides a means of studying the mechanisms of tumourigenesis in human thyroid epithelial cells induced by ionizing radiations, including tumours induced by single alpha particles such as from environmental natural radon and polonium and artificial plutonium and americium, and those induced by beta- or Auger-emissions from particular iodine isotopes. [ABSTRACT FROM AUTHOR]

We investigated the effect of 239Pu administered on day 4 of gestation on the number of CFU-S (spleen-colony forming units) in the foetal liver on day 17 of gestation in the C3H and BDF1 mouse. CFU-S numbers in the foetal liver were decreased significantly by 239Pu at doses 30 kBq/kg body weight in the BDF1 mouse, but were not changed by up to 900 kBq/kg in the C3H strain. Quantitative autoradiography on days 6, 8 and 10 of gestation and liquid scintillation counting on days 13 and 17 of gestation revealed no significant differences in the distribution and concentration of 239Pu between the foetoplacental units of these two strains. These findings suggest a strain difference in the effect of 239Pu alpha -irradiation on the development of the foetal haematopoietic systems in the mouse. [ABSTRACT FROM AUTHOR]

Reports on the difficulty for scientists and ethicists to analyze documents collected about secret government radiation experiments on humans. Article in the `Albuquerque Tribune' thrusting the experiments into limelight in November 1993; Manhattan Project scientists' injection of plutonium into terminal patients; Creation of the Advisory Committee on Human Radiation Experiments.