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PubMed1997

Perturbation in the 240Pu/239Pu global fallout ratio in local sediments following the nuclear accidents at Thule (Greenland) and Palomares (Spain).

It is well established that the main source of the plutonium found in marine sediments throughout the Northern Hemisphere is global stratospheric fallout, characterized by a typical 240Pu/239Pu atom ratio of approximately 0.18. Measurement of perturbations in this ratio at various sites which had been subjected to close-in fallout, mainly from surface-based testing (e.g. Bikini Atoll, Nevada test site, Mururoa Atoll), has confirmed the feasibility of using this ratio to distinguish plutonium from different fallout sources. In the present study, the 240Pu/239Pu ratio has been examined in samples of sediment (and soil) collected at Thule (Greenland) and Palomares (Spain), where accidents involving the release and dispersion of plutonium from fractured nuclear weapons occurred in 1968 and 1966, respectively. The 240Pu/239Pu ratio was measured by high-resolution alpha spectrometry and spectral deconvolution, and confirmed in the case of the most active samples by high-resolution X-ray spectrometry. Only samples which displayed plutonium heterogeneities, i.e. hot particles or concentrations well in excess (at least two orders of magnitude) of those expected from global fallout, were selected for analysis. The analytical results showed that at Thule the mean 240Pu/239Pu atom ratio was 0.033 +/- 0.004 (n = 4), while at Palomares the equivalent ratio appeared to be significantly higher at 0.056 +/- 0.003 (n = 4). Both ratios are indicative of low burn-up plutonium and are consistent with those reported for weapons-grade plutonium. It is noteworthy that the mean 238Pu/239Pu activity ratio in the Thule samples, at 0.0150 +/- 0.0017 (n = 4), was also lower than that measured in the Palomares samples, namely, 0.0275 +/- 0.0012 (n = 4). The 241Pu/239Pu ratios were similarly different. Finally, the data show, in contrast to Palomares, that not all of the samples from the Thule accident site were contaminated with plutonium of identical isotopic composition.

Air Pollutants, Radioactive↗
PubMed2000

Metabolism and dosimetry of actinide elements in occupationally-exposed personnel of Russia and the United States: a summary progress report.

The United States Transuranium and Uranium Registries (USTUR) and the Dosimetry Registry of the Mayak Industrial Association (DRMIA) have been independently collecting tissues at autopsy of plutonium workers in their respective countries for nearly 30 y. The tissues are analyzed radiochemically and the analytical data are used to develop, modify, or refine biokinetic models that describe the depositions and translocations of plutonium and transplutonium elements in the human body. The purpose of this collaborative research project is to combine the unique information on humans, gathered by the two Registries, into a joint database and perform analyses of the data. A series of project tasks are directly concerned with dosimetry in Mayak workers and involve biokinetic modeling for actinide elements. Transportability coefficients derived from in-vitro solubility measurements of actinide-containing aerosols (as measured by the DRMIA) were related to specific workplaces within Mayak facilities. The transportability coefficients of inhaled aerosols significantly affected the translocation rates of plutonium from the respiratory tract to the systemic circulation. Parameters for a simplified lung model, used by Branch No. 1, Federal Research Center Institute of Biophysics (FIB-1) and the Mayak Production Association for dose assessment at long times after inhalation of plutonium-containing aerosols, were developed on the basis of joint USTUR and DRMIA data. This model has separate sets of deposition and transfer parameters for three aerosol transportability groups, allowing work histories of the workers to be considered in the dose-assessment process. FIB-1 biokinetic models were extended to include the distributions of actinide elements in systemic organs of workers, and a relationship between the health of individual workers and plutonium distribution in tissues was determined. Workers who suffered from liver diseases generally had a smaller fraction of systemic plutonium in the liver at death and a larger fraction in the skeleton than did relatively healthy workers. Also, the fraction of total systemic plutonium excreted per day was significantly greater for workers with liver diseases than for relatively healthy workers. These observations could have a considerable effect on organ dosimetry in health-impaired workers whose dose assessments were based solely on urinary excretion rates. A comparison of this model to other biokinetic models, such as those published by the International Commission for Radiological Protection, is currently underway as is the documentation of uncertainty estimates associated with the model.

Aerosols↗
PubMed1976

Bone tumors induced by inhalation of 238PuO2 in dogs.

Plutonium-238, an alpha-emitting radionuclide, is used as a heat source in thermoeleltric power generators such as have been employed on lunar expeditions of communications satellites and in cardiac pacemakers. It has an 86.4 year half-life and emits 5.5 MeV alpha particles. Beagle dogs were given single 10-30 minute exposures to 238PuO2 aerosols to study the long-term translocation of plutonium and biological effects. Dogs with a terminal body burden ranging from 7-260 muCi were euthanized due to respiratory insufficiency related to plutonium-induced pneumonitis during the first 3 years after exposure. Nine of the 11 dogs euthanized during the 4-6 year postexposure period had osteosarcomas. The terminal plutonium body burden in the tumor-bearing dogs ranged from 0.5-2.6 muCi with 30-55% of the plutonium in the skeleton. Experiments are in progress to further define the dose-effect relationship of inhaled 238PuO2 and investigate the mechanisms of plutonium-induced neoplasia.

Alkaline Phosphatase↗
PubMed2004

Levels and trends of radioactive contaminants in the Greenland environment.

Levels of radioactive contaminants in various Greenland environments have been assessed during 1999-2001. The source of 137Cs, 90Sr and (239,240)Pu in terrestrial and fresh water environments is mainly global fallout. In addition, the Chernobyl accident gave a small contribution of 137Cs. Reindeer and lamb contain the largest observed 137Cs concentrations in the terrestrial environment--up to 80 Bq kg(-1) fresh weight have been observed in reindeer. Due to special environmental conditions, 137Cs is transferred to landlocked Arctic char with extremely high efficiency in South Greenland leading to concentrations up to 100 Bq kg(-1) fresh weight. In these cases very long ecological half-lives are seen. Concentrations of 99Tc, 137Cs and 90Sr in seawater and in marine biota decrease in the order North-East Greenland and the coastal East Greenland current > South-West Greenland > Central West Greenland and North-West Greenland > Irmiger Sea-Faroe Islands. The general large-scale oceanic circulation combined with European coastal discharges and previous contamination of the Arctic Ocean causes this. As the same tendency is seen for the persistent organic pollutants (POPs) DDT and PCB in marine biota, it is suggested that long-distance oceanic transport by coastal currents is a significant pathway also for POPs in the Greenland marine environment. The peak 99Tc discharge from Sellafield 1994-1995 has only been slightly visible in the present survey year 2000. The concentrations are expected to increase in the future, especially in East Greenland. The Bylot Sound at the Thule Airbase (Pituffik) in North-West Greenland was contaminated with plutonium and enriched uranium in a weapons accident in 1968. Biological activity has mixed accident plutonium efficiently into the new sediments resulting in continued high surface sediment concentrations three decades after the accident. Transfer of plutonium to benthic biota is low--and lower than observed in the Irish Sea. This is supposed to be caused by the physico-chemical form of the accident plutonium. A recent study indicates that 'hot particles' hold considerably more plutonium than previously anticipated and that the Bylot Sound sediments may account for the major part of the un-recovered plutonium after the accident, i.e. approximately 3 kg.

Animals↗
PubMed2003

Molecular interfacial reactions between Pu(VI) and manganese oxide minerals manganite and hausmannite.

The sorption of Pu(VI) onto manganite (MnOOH) and hausmannite (Mn3O4) was studied as a function of time, solution pH, and initial plutonium concentration. Kinetic experiments indicate that the surface complexation of plutonium occurs over the first 24 h of contact with the mineral surface. The sorption increases with pH beginning at pH 3 until it reaches a maximum value of 100% at pH 8 (0.0011-0.84 micromol of Pu/m2 of manganite and 0.98-1.2 micromol of Pu/m2 of hausmannite) and then decreases over the pH range from 8 to 10. The ratio of solid to solution was 10 mg/mL for manganite experiments and 4 mg/mL for hausmannite samples. Carbonate was not excluded from the experiments. The amount of plutonium removed from the solution by the minerals is determined by a combination of factors including the plutonium solution species, the surface charge of the mineral, and the mineral surface area. X-ray absorption fine structure taken at the Pu L(III) edge were compared to plutonium standard spectra and showed that Pu(VI) was reduced to Pu(IV) after contact with the minerals. Plutonium sorption to the mineral surface is consistent with an inner-sphere configuration, and no evidence of PuO2 precipitation is observed. The reduction and complexation of Pu(VI) by manganese minerals has direct implications on possible migration of Pu(VI) species in the environment.

Adsorption↗
PubMed1987

Differences in the uptake of transferrin bound 239Pu and 59Fe into multicellular spheroids of hepatocytes from adult male rats.

Hepatocytes were cultured as monolayers and multicellular spheroids, respectively. The uptake of both transferrin-bound metals, iron and plutonium, differed significantly between these two culture systems. The uptake into the multicellular spheroids for plutonium was about 30 times greater, and for iron about 4 times greater, than in monolayer-cultured hepatocytes, which is not a consequence of proliferation and/or de-differentiation of the hepatocytes in the multicellular spheroid culture system. A comparison of the iron and plutonium uptake showed that plutonium was delivered to the cells to an 8-fold greater extent than iron if the hepatocytes were cultured as spheroids. Additionally, the binding of plutonium was not inhibited by preincubation of the spheroids with the iron-transferrin complex. Therefore, we propose that there are two different binding sites for iron and plutonium on hepatocyte membranes.

Animals↗
PubMed1995

Comprehensive appraisal of 239 + 240Pu in soils around Rocky Flats, Colorado.

Plutonium contamination of soils around Rocky Flats Environmental & Technology Site, near Golden, Colorado, resulted from past outdoor storage practices and subsequent remobilization due to inadequate cleanup practices. Until now human-health risk assessment has not been performed because of a lack of sufficient information regarding the spatial extent of 239 + 240Pu in soils. The purpose of this work was to elucidate the extent of plutonium contamination in surface soils, and to assess the uncertainty associated with the spatial distribution of 239 + 240Pu around Rocky Flats Environmental & Technology Site. Four data sets were collected or compiled for this investigation: (1) samples collected from 240 plots of 1.01- or 4.05-hectare by compositing 25 evenly-spaced samples from the upper 0.64 cm in each plot; (2) samples collected from the upper 5 cm of soil in 167 of the same 240 plots by compositing 10 samples from the center of each plot; (3) historical data compiled from samples collected between 1969 and 1973, considered to be the most indicative of the original release; and (4) the exhaustive data set that contains the samples from 1, 2, and 3 and other published data sets collected between 1974 and 1994. These latter samples varied in depth and method of sampling. Plutonium activity reported in the exhaustive data set ranged from 0.03 Bq kg-1 to 407,000 Bq kg-1 with a mean of 1,443 Bq kg-1, median of 6.6 Bq kg-1, standard deviation of 18,463 Bq kg-1, and a coefficient of variation of 12.6. The technique of nonparametric indicator kriging was used to model four conditional cumulative distribution functions of 239 + 240Pu in soils around Rocky Flats Environmental & Technology Site. Each of the conditional cumulative distribution functions was used to generate an E-type (mean of the conditional cumulative distribution functions) surface. The resulted surfaces were consistent with the hypothesis that the westerly winds were the dominant mechanism of plutonium dispersal. Other processes, such as downstream transport of sediment along local southeast-trending drainages, may have additionally moved small amounts of plutonium. The conditional cumulative distribution functions were also used to construct probability of exceedance maps of 239 + 240Pu in soils. For the purpose of this report two threshold values for the probability maps were selected: (1) the mean and the highest measured global fallout of plutonium (1.48 and 2.96 Bq kg-1, respectively); and (2) the programmatic preliminary remediation goal for residential occupancy scenario (126 Bq kg-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Colorado↗
PubMed1997

Resuspension studies in the Marshall Islands.

The contribution of inhalation exposure to the total dose for residents of the Marshall Islands was monitored at occasions of opportunity on several islands in the Bikini and Enewetak Atolls. To determine the long-term potential for inhalation exposure, and to understand the mechanisms of redistribution and personal exposure, additional investigations were undertaken on Bikini Island under modified and controlled conditions. Experiments were conducted to provide key parameters for the assessment of inhalation exposure from plutonium-contaminated dust aerosols: characterization of the contribution of plutonium in soil-borne aerosols as compared to sea spray and organic aerosols, determination of plutonium resuspension rates as measured by the meteorological flux-gradient method during extreme conditions of a bare-soil vs. a stabilized surface, determination of the approximate individual exposures to resuspended plutonium by traffic, and studies of exposures to individuals in different occupational environments simulated by personal air sampling of workers assigned to a variety of tasks. Enhancement factors (defined as ratios of the plutonium-activity of suspended aerosols relative to the plutonium-activity of the soil) were determined to be less than 1 (typically 0.4 to 0.7) in the undisturbed, vegetated areas, but greater than 1 (as high as 3) for the case studies of disturbed bare soil, roadside travel, and for occupational duties in fields and in and around houses.

Administration, Inhalation↗
PubMed1975

Comparative measurements of the shortterm lung clearance and translocation of PuO2 and mixed Na2O + PuO2 aerosols in mice.

Mice were exposed to aerosols of either plutonium dioxide alone, or mixed oxides of plutonium and sodium with atomic ratios (Na/Pu) in the range 1.5 to 16. In the case of the mixed oxides, the lung clearance of the plutonium was represented by the sum of two exponentials, of which the short-term component accounted for 27 +/- 8% of the initial lung content with a clearance half-time of 6.0 +/- 2.7 h. These measurements were made over a period of up to 35 days after exposure, and similar measurements for a plutonium dioxide fume indicated that any early clearance phase was obscured by data variability, but was small and probably accounted for less than 10% of the initial lung deposit. The translocation of plutonium to the liver and skeleton by 1 day after exposure represented about 0.05% of the initial lung content in the case of the plutonium dioxide fume, and 7% of the initial lung content for the mixed oxide particulate where the atomic ratio was 16. The results of the animal exposures are discussed briefly with respect to the physical characterization of the particulate by electron microscopy, and in vitro filtration methods.

Aerosols↗
PubMed1995

The influence of radiation and nonradiation factors on the lung cancer incidence among the workers of the nuclear enterprise Mayak.

For the estimation of radiation lung cancer risk for a human being it is important to take into account different etiological factors because of the polyetiology of this disease. This work was the aim of a retrospective investigation ("case-control") of 500 workers of a nuclear enterprise that had been gamma-irradiated in a wide dose range and had had exposure to airborne 239Pu. One hundred sixty-two persons contracted lung cancer (morbidity), and 338 persons that had not fallen ill served as pair control. Eleven potential risk factors were evaluated using a logistic regression model, five insignificant factors were excluded, and the remaining factors were arranged (by odds ratio) in decreasing order: smoking > plutonium pneumosclerosis > plutonium incorporation in body > chronic obstructive pulmonary diseases (COPD) > decrease of body mass > external gamma-irradiation. The percentage of histologically confirmed adenocarcinoma among the nuclear enterprise workers was 74%, which is significantly higher than 33% among the population that did not work at the enterprise, particularly in the case of high (more than 11 kBq) plutonium incorporation by the nuclear workers. The localization of tumors in this cohort is more frequently in the lower and middle lung lobes and at the periphery. Each of the histological types of lung cancer has manifested a different degree of correlation with particular factors. The adenocarcinoma has the most frequent correlation with the radiation factors; the odds ratio for plutonium incorporation and plutonium pneumosclerosis is 2.9 (95% CI = 1.0-8.4); for external gamma-irradiation the odds ratio is 1.9 (0.99-3.5); the odds ratio for smoking is 4.3 (1.9-9.9). The squamous-cell carcinoma has the highest correlation with non-occupational factors: with smoking the OR is 6.8 (1.2-38.7), with the chronic obstructive pulmonary diseases the odds ratio is 3.9 (1.8-8.4), and with body mass decrease the odds ratio is 2.1 (0.94-4.6); odds ratio for plutonium incorporation is 4.2 (1.4-12.8). The small-cell carcinoma has correlation with body mass decrease [odds ratio = 2.9 (1.2-7.6)] and high level of smoking [smoking index > 500; odds ratio = 3.5 (1.4-8.9)]. The portion of the occupational cancers among the workers of the nuclear enterprise, evaluated on the base of attributive risk, is 26%, with 57% for adenocarcinoma, 9% for squamous-cell carcinoma, and 8% for small-cell carcinoma. The investigation is continued to assess the dose-effect and factors interactions.

Aged↗
PubMed1999

Characteristics of the cohort of workers at the Mayak nuclear complex.

At Branch No. 1 of the Russian State Research Center "Biophysics Institute", a registry has been created of workers at the "Mayak" Production Association, the first nuclear complex in Russia. This registry includes 18,830 persons hired at Mayak's nuclear reactors and radiochemical and plutonium production plant between 1948 and 1972. Twenty-five percent of these workers are women. As of December 31, 1994, the vital status is known for approximately 90% of the cohort members. A total of 5,118 persons have died. The cause for 97% of total deaths has been ascertained. The cohort members were exposed to both external gamma radiation and internal radiation from incorporated plutonium. The plutonium body burden has been measured in 30% of the cohort members with potential for plutonium exposure. External gamma-ray doses were in the range from tenths of milligrays to about 10 Gy, and plutonium body burdens were up to about 260 kBq. In view of the nature of the Mayak worker cohort, it has the potential to provide reasonably precise, quantitative estimates of the long-term health effects associated with chronic low-dose-rate exposure to external gamma radiation as well as internal radiation from plutonium. However, a number of issues must be addressed before credible risk estimates can be obtained from this cohort. These issues include the development of an appropriate internal comparison group and/or external rates and separating of the effects of internal and external exposures on risk estimates.

Cause of Death↗
PubMed1980

241Plutonium deposition and redistribution in the rat rib.

Using the techniques of 241plutonium autoradiography and plutonium alpha-autoradiography the distribution of intravenously injected plutonium in the rat rib has been investigated, at times up to 4 months after injection. The results showed that at some time plutonium either became buried in the bone cortex or was resorbed. Plutonium which was resorbed was found in osteoclasts and macrophages. Subsequently, much of the resorbed plutonium was redeposited. The dosimetric implications of the results are discussed.

Alpha Particles↗
PubMed2003

Successful DTPA therapy in the case of 239Pu penetration via injured skin exposed to nitric acid.

This paper presents results of the radiological study and DTPA therapy for a worker exposed to a plutonium nitrate solution. Plutonium levels were measured in excreta, blood, plasma and wound for several weeks. Plutonium renal clearance ranged from 110-190 ml min(-1) to 3-4 ml min(-1) at different stages of chelation therapy. Plutonium absorption into blood from the injured skin amounted to 4.3%. As a result of intensive therapy, 96% of absorbed plutonium was successfully excreted.

Administration, Topical↗
PubMed1998

Cancer mortality in relation to monitoring for radionuclide exposure in three UK nuclear industry workforces.

Cancer mortality in 40,761 employees of three UK nuclear industry facilities who had been monitored for external radiation exposure was examined according to whether they had also been monitored for possible internal exposure to tritium, plutonium or other radionuclides (uranium, polonium, actinium or other unspecified). Death rates from cancer were compared both with national rates and with rates in radiation workers not monitored for exposure to any radionuclides. Among workers monitored for tritium exposure, overall cancer mortality was significantly below national rates [standardized mortality ratio (SMR) = 83, 165 deaths; 2P = 0.02] and none of the cancer-specific death rates was significantly above either the national average or rates in non-monitored workers. Although the overall death rate from cancer in workers monitored for plutonium exposure was also significantly low relative to national rates (SMR = 89, 581 deaths; 2P = 0.005), mortality from pleural cancer was significantly raised (SMR = 357, nine deaths; 2P = 0.002); none of the rates differed significantly from those of non-monitored workers. Workers monitored for radionuclides other than tritium or plutonium also had a death rate from all cancers combined that was below the national average (SMR = 86, 418 deaths; 2P = 0.002) but prostatic cancer mortality was raised both in relation to death rates in the general population (SMR = 153, 37 deaths; 2P = 0.02) and to death rates in radiation workers who had not been monitored for exposure to any radionuclide [rate ratio (RR) = 1.65; 2P = 0.03]. Mortality from cancer of the lung was also significantly increased in workers monitored for other radionuclides compared with those of radiation workers not monitored for exposure to radionuclides (RR = 1.31, 164 deaths; 2P = 0.01). For cancers of the lung, prostate and all cancers combined, death rates in monitored workers were examined according to the timing and duration of monitoring for radionuclide exposure, with rates of radiation workers not monitored for any radionuclide forming the comparison group. In tritium-monitored workers, RRs for prostatic cancer varied significantly according to the number of years in which they were monitored (2P = 0.03). In workers monitored for plutonium exposure, RRs for all cancers combined increased with the number of years in which they were monitored (2P = 0.04) and with the number of years since first monitoring (2P = 0.0003). There was little suggestion of systematic variation in RRs for workers monitored for other radionuclides in relation to the timing or duration of monitoring, nor did it appear that their raised rates of cancer of the lung and prostate were explained by external radiation dose. These analyses of cancer mortality in relation to monitoring for radionuclide exposure reported in a large cohort of nuclear industry workers suggest that certain patterns of monitoring for some radionuclides may be associated with higher death rates from cancers of the lung, pleura, prostate and all cancers combined. Some of these findings may be due to chance. Moreover, because of the paucity of related data and lack of information about other possible exposures, such as whether plutonium workers are more likely to be exposed to asbestos, firm conclusions cannot be drawn at this stage. Further investigations of the relationship between radionuclide exposure and cancer in nuclear industry workers are needed.

Adolescent↗
PubMed2006

Americium in the beagle dog: biokinetic and dosimetric model.

A biokinetic model of the systemic distribution of americium in the beagle dog is presented. The model is based on a previous biokinetic model of plutonium. The data sets used for the development of the model were the measurements of excreted activity (urine and feces) and organ burdens (skeleton, liver, and other soft tissues) for different levels of initial injected activity. In developing the model, the compartmental structure of the skeleton of the plutonium model was adopted, and only the numerical values of parameters were adapted. The model well describes the fractions of americium in the skeleton, liver, and soft tissues and the total fraction excreted in urine and feces. The tuning of the liver clearance parameter provides a realistic description of the change in the partitioning between liver and skeleton for different injection levels. The most significant features of the biokinetics and dosimetry of americium and plutonium in beagles are compared. The total fractions of the clearance to the skeleton and the liver are roughly equal to the value for plutonium, but the partitioning of americium between these organs is reversed with respect to the partitioning of plutonium. 241Am doses to liver and skeleton are similar to 239Pu doses, owing to some counteracting factors. For the highest injection level, the liver mass is dependent on the time post injection. For the skeletal tissues, the dose to the cortical endosteum by far exceeds the dose to the trabecular endosteum and the red marrow. The model provides the basis for statistical survival analyses and risk estimates.

Americium↗
PubMed2003

Cancer mortality risk among workers at the Mayak nuclear complex.

At present, direct data on risk from protracted or fractionated radiation exposure at low dose rates have been limited largely to studies of populations exposed to low cumulative doses with resulting low statistical power. We evaluated the cancer risks associated with protracted exposure to external whole-body gamma radiation at high cumulative doses (the average dose is 0.8 Gy and the highest doses exceed 10 Gy) in Russian nuclear workers. Cancer deaths in a cohort of about 21,500 nuclear workers who began working at the Mayak complex between 1948 and 1972 were ascertained from death certificates and autopsy reports with follow-up through December 1997. Excess relative risk models were used to estimate solid cancer and leukemia risks associated with external gamma-radiation dose with adjustment for effects of plutonium exposures. Both solid cancer and leukemia death rates increased significantly with increasing gamma-ray dose (P < 0.001). Under a linear dose-response model, the excess relative risk for lung, liver and skeletal cancers as a group (668 deaths) adjusted for plutonium exposure is 0.30 per gray (P < 0.001) and 0.08 per gray (P < 0.001) for all other solid cancers (1062 deaths). The solid cancer dose-response functions appear to be nonlinear, with the excess risk estimates at doses of less than 3 Gy being about twice those predicted by the linear model. Plutonium exposure was associated with increased risks both for lung, liver and skeletal cancers (the sites of primary plutonium deposition) and for other solid cancers as a group. A significant dose response, with no indication of plutonium exposure effects, was found for leukemia. Excess risks for leukemia exhibited a significant dependence on the time since the dose was received. For doses received within 3 to 5 years of death the excess relative risk per gray was estimated to be about 7 (P < 0.001), but this risk was only 0.45 (P = 0.02) for doses received 5 to 45 years prior to death. External gamma-ray exposures significantly increased risks of both solid cancers and leukemia in this large cohort of men and women with occupational radiation exposures. Risks at doses of less than 1 Gy may be slightly lower than those seen for doses arising from acute exposures in the atomic bomb survivors. As dose estimates for the Mayak workers are improved, it should be possible to obtain more precise estimates of solid cancer and leukemia risks from protracted external radiation exposure in this cohort.

Adult↗
PubMed1982

Relationship between blood flow, bone structure, and 239Pu deposition in the mouse skeleton.

The rate at which blood is supplied to several bones in female CBA mice was calculated from 18F measurements in bone and blood. Blood flow measurements were compared with plutonium uptake in whole bone and on endosteal and periosteal bone surfaces. The results showed that: (a) the rate at which blood is supplied to bone determines the rate of deposition of plutonium; (b) there is a threshold rate of blood supply below which plutonium is not deposited; and (c) the rate of blood supply determines the density of plutonium deposition on endosteal but not no periosteal bone surfaces. These results are discussed in the light of the current bone blood supply hypotheses.

Animals↗
PubMed1999

240Pu/239Pu isotopic ratios and 239 + 240Pu total measurements in surface and deep waters around Mururoa and Fangataufa atolls compared with Rangiroa atoll (French Polynesia).

The average values of 240Pu/239Pu mass isotopic ratios of plutonium deposited in Mururoa and Fangataufa atoll sediments by French atmospheric nuclear tests range from 3.5 to 5%. In order to assess the near field and far field influence of those deposits in the open ocean, two water profiles were measured for 239 + 240Pu and 240Pu/239Pu using, for the first time, an Inductively Coupled Plasma Mass Spectrometer which was developed to achieve femtogram detection limits. One site was located at the limit of the French territorial waters, which is 22 km distant from Mururoa. The second site was located close to Rangiroa atoll, at a distance of approximately 1200-km from French nuclear test sites. The sample volumes were approximately 500 litres and plutonium was purified prior to mass spectrometry and alpha spectrometry measurements. In Rangiroa, the 239 + 240Pu profile is comparable with those already determined in world open oceans but the maximum detected activity, 9 mBq/m3 at 500-600 m is a lot lower than those measured in the northern hemisphere. 240Pu/239Pu ratios were measured between 500 and 1000 m and were not statistically different from the typical 0.18 +/- 0.01 ratio which characterises the global fallout. Consequently, any influence of plutonium from the tests in Mururoa and Fangataufa is not apparent at Rangiroa. The vertical distribution of 239 + 240Pu near Mururoa shows similar changes with depth but with a slight increase in concentration. 240Pu/239Pu mass ratios vary with depth, from 7 to 10% in the upper 500 m and in the deep waters (below 1000 m) to 15-16% between 600 and 1000 m. A contribution from plutonium deposited in the sediments at Mururoa and Fangataufa is observed at the limit of territorial waters, especially in surface and deep waters.

Half-Life↗