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PubMedDate not supplied

Measurement of radiocaesium, radiostrontium, and plutonium in whole diets, following deposition of radioactivity in the UK originating from the Chernobyl power plant accident.

Radionuclide contamination of whole diets as a result of the Chernobyl accident has been measured following the collection of individual diets from adults and children during 1 week in June 1986. The study was conducted in three different parts of the UK, to represent rural areas of both high and low deposition of Chernobyl fallout, and an urban area where the food supply was likely to be derived from a more diverse range of sources. The overall caesium-137 plus caesium-134 concentrations in the diets was less than 5 Bq kg-1 fresh weight, and ranged from less than 0.8 Bq kg-1 to 22 Bq kg-1, the highest levels being found in diets from the high deposition area. The isotopic ratios confirmed contamination to have been predominantly of Chernobyl origin. These levels of radiocaesium would have given rise to an average committed effective dose equivalent to age 70 of less than 0.4 microSv, with a range of less than 0.05 microSv to 1.9 microSv, from intakes in the study week. The opportunity was also taken to analyse the samples for weapons fallout contamination, that is, strontium-89/strontium-90 and plutonium-239/plutonium-240. No diet contained strontium above the reporting level of 0.2 Bq kg-1 but 18% of the diets contained plutonium above the limits of detection (0.1 mBq kg-1), the highest of these being 12 mBq kg-1, found in a diet from one of the low deposition areas.

Accidents↗
PubMed1980

The reactions of l nm particles of plutonium-238 dioxide and curium-244 dioxide with lung fluid.

The reactions of 1 nm particles of plutonium-238 dioxide and curium-244 dioxide with rat lung fluid have been studied both in vitro and in vivo. The plutonium-238 particles are positively charged and combine by electrostatic attraction with the negative pulmonary surfactant which mediates the transfer of radioactivity to the blood. In contrast the curium-244 particles are negative and are assumed to diffuse passively through the alveolar walls. The results emphasise that electrostatic charge is an important factor governing the reaction of 1 nm actinide oxide particles with macromolecules.

Actinoid Series Elements↗
PubMed1980

The induction of chromosome aberrations in human lymphocytes by in vitro irradiation with alpha-particles from plutonium-239.

The yields of unstable chromosome aberrations induced in human lymphocytes by alpha-particles from plutonium-239 have been measured. Plutonium citrate solution was mixed with heparinized blood so that doses of 13--160 rad were delivered in 24 hours. Dicentric aberration yields (Y) fitted best to the linear expression Y = 3 . 72 +/- 0 . 23 x 10(-3) rad-1. Inclusion of a 6 . 5 rad point resulting from a 1 . 7 hour irradiation raised the yield coefficient insignificantly to 3 . 75 +/- 0 . 24 x 10(-3). The aberration yields are in good agreement with data from curium-242 alpha-particles obtained in this laboratory but they are much lower than those obtained in two other laboratories. Reasons for this disagreement are examined.

Alpha Particles↗
PubMed1985

Chromosome studies in plutonium workers.

Chromosome analyses have been performed on peripheral blood lymphocytes from 54 men with estimates of plutonium body burdens in excess of 296 Bq. Both stable and unstable aberrations were scored using a banding technique and breakpoints noted. In discussing the significance of aberration frequencies the relative proportions of the different types of aberration and their distribution have been considered and account has been taken of external radiation exposure. It is suggested that significant depositions of plutonium do cause an increase in chromosome aberrations. The distribution of the breakpoints in the controls showed an excess in chromosomes 7 and 14. The formation and survival of radiation-induced breakpoints was randomly distributed amongst the chromosomes according to length. The distribution of the breakpoints within the chromosomes showed an excess in the centromeres and telomeres. Possible hot spots occurred in some of these regions and also in certain bands of the intermediate regions of the chromosomes.

Adult↗
PubMed1991

Alpha-particle irradiation of haemopoietic tissue in pre- and postnatal mice. 1: Distribution of plutonium-239 after mid-term contamination.

Pregnant mice (at 13 days gestation) and age-matched controls were injected with 30 kBq 239Pu/kg and the distribution of plutonium in maternal and foetal tissues measured. Approximately 2% of the activity injected into the mother reached each foetus in 24 h, 95% of which was contained in membranes and placenta. The concentration of plutonium in foetal liver was 3 times the average foetal body concentration; both liver and body concentrations in the foetus increased by the end of gestation. Each pup accumulated only 0.01% extra injected activity after 9 days lactation and, as the resulting concentrations in the neonatal skeleton were low, we conclude that the greatest haemopoietic risk to the offspring from mid-term contamination in utero is in the foetal liver (which received an average dose of 10-14 mGy between the time of mid-term contamination and birth). By the end of gestation about one-quarter of the original activity was transferred to foetal tissues from the maternal liver and skeleton. No significant changes in maternal distribution were detected as a result of lactation. The results of this study are discussed, along with a compilation of previously published data.

Animals↗
PubMed1996

Transferrin-mediated uptake of plutonium by spermatogenic tubules.

Using isolated rat seminiferous tubules as an in vitro model, we have found that 238Pu can cross the blood-tubule barrier and accumulate within tubules in a time dependent manner. Furthermore, similar to 59Fe, tubule 238Pu uptake was inhibited by the addition of excess transferrin, suggesting that plutonium may utilize the physiological iron-transferrin pathway to cross the blood-tubule barrier. However unlike 59Fe, 238Pu was only transiently associated with the tubules, suggesting differences in the intracellular processing of these radionuclides. The assumptions made in the estimation of doses to the human testis from incorporated plutonium are considered.

Animals↗
PubMed1997

Radiation-induced transformation of SV40-immortalized human thyroid epithelial cells by single exposure to plutonium alpha-particles in vitro.

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 alpha-particles 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.

Alpha Particles↗
PubMed1998

Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles (Cerastoderma edule) from the Irish Sea.

Our previous studies have indicated lower values of the gut transfer factor ('f1 values') for plutonium and americium in winkles (Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles (Carastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 h samples of urine and faeces. Urine samples indicated f1 values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7 x 10(-4) with an arithmetic mean in the range (2-3) x 10(-4), and for americium up to 2.6 x 10(-4) with an arithmetic mean of 1.2 x 10(-4). Limited data based on volunteers eating cockles from the Solway suggest that f1 values for americium may be greater at distance from Sellafield. The measured values compare with 5 x 10(-4) used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f1 value in the region of 0.2, twice the value currently used by ICRP. For 137Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f1 = 1.0. Technetium-99 gave f1 values up to about 0.6, in reasonable conformity with the ICRP value of 0.5.

Americium↗
PubMed2000

The assessment of organ doses from plutonium for an epidemiological study of the Sellafield workforce.

An epidemiological study of mortality and cancer rates in plutonium workers at the Sellafield nuclear installation has been carried out by researchers at the London School of Hygiene and Tropical Medicine. The study required the assessment of organ-specific doses from plutonium for more than 5000 workers over a period of 40 years. This was a major undertaking as it involved the reconstruction of annual received doses from the results of some 223,000 urine samples that had been provided by the workers in the study. This paper outlines the techniques and strategies adopted in order to generate best estimates of dose from the available data, and presents summaries of these doses.

Body Burden↗
PubMed2003

Comparison of predicted with observed biokinetics of inhaled plutonium nitrate and gadolinium oxide in humans.

The absorption kinetics to blood of plutonium and gadolinium after inhalation as nitrate and oxide in humans and animals has been studied. For each material, values describing the time dependence of absorption were derived from the studies in animals and used with the ICRP human respiratory tract model to predict lung retention and cumulative amounts to blood for the volunteers inhaling the same materials. Comparison with the observed behaviour in the volunteers suggests that absorption of plutonium and gadolinium is reasonably species independent, and that data obtained from animal studies can be used to assess their biokinetic behaviour in humans.

Absorption↗
PubMed2004

A review of contributions of human tissue studies to biokinetics, bioeffects and dosimetry of plutonium in man.

This paper briefly reviews the contributions made by human tissue studies to improved understanding of the biokinetics, dosimetry and potential bioeffects of plutonium in man. It includes consideration of tissue donations from both environmental and occupational populations, along with a brief history of human experience with plutonium and consideration of the bioethical aspects of post-mortem human tissue sampling.

Bioethics↗
PubMed1982

Soil plutonium and cesium in stream channels and banks of Los Alamos liquid effluent-receiving areas.

Stream channel sediments and adjacent bank soils found in three intermittent streams used for treated liquid effluent disposal at Los Alamos, New Mexico were sampled to determine the distribution of 238Pu, 239,240Pu and 137Cs. Radionuclide concentrations and inventories were determined as functions of distance downstream from the waste outfall and from the center of the stream channel, soil sampling depth, stream channel-bank physiography, and the waste use history of each disposal area. Radionuclide concentrations in channel sediments were inversely related to distances up to 10 km downstream from the outfalls. For sites receiving appreciable waste effluent additions, contaminant concentrations in bank soils decreased with perpendicular distances greater than 0.38 m from the stream channel, and with stream bank sampling depths greater than 20-40 cm. Concentrations and total inventories of radionuclides in stream bank soils generally decreased as stream bank height increased. Inventory estimates of radionuclides in channel sediments exhibited coefficients of variation that ranged 0.41-2.6, reflecting the large variation in radionuclide concentrations at each site. Several interesting temporal relationships of these radionuclides in intermittent streams were gleaned from the varying waste use histories of the three effluent-receiving areas. Eleven yr after liquid wastes were added to one canyon, the major radionuclide inventories were found in the stream bank soils, unlike most of the other currently-used receiving areas. A period of time greater than 6 yr seems to be required before the plutonium in liquid wastes currently added to the canyon is approximately equilibrated with the plutonium in the bank soils. These observations are discussed relative to waste management practices in these southwestern intermittent streams.

Cesium Radioisotopes↗
PubMed1983

Metabolism of plutonium introduced as Tri-N-Butylphosphate complex in the rat and removal attempts by DTPA.

The metabolism of plutonium introduced as the Pu-Tri-N-Butylphosphate complex (Pu-TBP) was studied in rats after inhalation, injection and ingestion. Early translocation and distribution of 239Pu in organs for 30-400 days after inhalation exposure are presented. The tracheobronchial clearance was impaired at early times, followed from about one week by clearance from the deep lung as characterized by a half time of 100 days. Skeleton was the main organ for deposition of the transferable fraction. The bone burden reached a plateau value of 10% of Initial Lung Burden (ILB) at 50 days after inhalation, while retention in liver reached 2% of ILB at 50 days and decreased to 0.3% by 1 yr after inhalation. Thirty days after intramuscular injection, translocated plutonium (15% of injected activity) resulted in a skeletal deposit that was 17.5 times higher than the deposit in the liver. By both routes, inhalation and intramuscular injection, 239Pu was transported in the blood as a Pu-transferrin complex. However, therapy with 30 mumol . kg-1 DTPA was ineffective. This result, together with the magnitude of the skeletal deposit observed, indicate that Pu-TBP follows a specific metabolic pathway that results in a Pu-transferrin complex that is more stable than the complexes described after Pu nitrate or citrate contamination. Lastly, absorption of Pu-TBP from the gut was poor, reaching 0.015% of the Pu given by gavage, a value not significantly different from the values assumed by ICRP 30 for class W compounds.

Administration, Oral↗
PubMed1983

A comparison of systemic burdens at autopsy to estimates based on health physics data for selected plutonium workers.

To obtain an estimate of the systemic burden of plutonium in a worker, the health physicist must apply bioassay data, both in vivo and excreta data to mathematical models which describe the translocation of plutonium in humans. To assist in obtaining the best estimate possible, the health physicist often utilizes field data including results of air sampling at the work location, chemical form and solubility of the material to which the worker has or may have been exposed and contamination surveys of the worker himself. The estimate made by the health physicist while the worker is alive is compared to the systemic burden based on autopsy data to evaluate the accuracy of the model used. Preliminary conclusions regarding findings of the study to date are presented.

Autopsy↗
PubMed1987

Plutonium and lung cancer.

The National Plutonium Workers Study surveys workers at three major U.S. Department of Energy facilities who were exposed to Pu and other radioactive substances. The purpose of the study is to measure adverse health effects, if any, which arise from exposure. Most exposures occur from inhalation of highly insoluble forms of plutonium oxide, and from animal studies, lung cancer is the most likely outcome. To date, the studies have shown that lung cancer mortality among highly exposed persons is surprisingly low when compared to national averages.

Environmental Exposure↗
PubMed1989

Plutonium distribution and oxidation states in a reactor leaching ponds system.

Concentrations of 239,240Pu and 238Pu in water, net plankton (algal material), suspended particulates and sediment, as well as Pu oxidation states in filtered water, were determined in a test reactor leaching ponds system in southeastern Idaho. The highest Pu concentration in the ponds system was found in net plankton, and concentrations varied significantly between sampling dates. Plutonium Concentration Ratios (CR) for plankton ranged from 3 X 10(4) to 4 X 10(5). The lowest Pu concentration was found in filtered water, primarily because of the absence of complexing agents. The majority of Pu in filtered water was in true solution (60-87%) or present in colloidal particles smaller than 0.22 micron. Plutonium association with sediment was inversely related to particle size. The "environmental" distribution coefficients (Kd) for Pu ranged from 1.6 X 10(4) to 1.2 X 10(5) reflecting the importance of sediments as the main reservoir for Pu in the ponds system. No significant differences were noted between CR or Kd values for 239,240Pu and 238Pu. The reduced Pu oxidation states (III and IV) fractions ranged from 57% to 71% of the total dissolved Pu in water. This is in contrast with oxidation states distribution from other large aquatic systems (Great Lakes and the Irish Sea) where Pu is predominately in oxidized (V and VI) forms.

Animals↗
PubMed1991

A 42-y medical follow-up of Manhattan Project plutonium workers.

Twenty-six white male subjects, who worked with plutonium (239Pu) during World War II at Los Alamos, have been given medical examinations periodically over a period of 42 y to identify potential health effects. Inhalation was the primary mode of Pu exposures. The latest examinations, including urine bioassay and in-vivo measurements for radioactivity, were performed in late 1986 and 1987. The average age of the 22 living subjects in 1986 was 66 y. The diseases and physical changes noted in these persons are characteristic of a male population in their 60s. Estimates of individual Pu depositions, including lung burdens, as of 1987 or at time of death range from 52 to 3180 Bq (1.4 to 86 nCi) with a median value of 500 Bq (13.5 nCi). Four persons from the original group had died as of 1987. The causes of death were lung cancer, myocardial infarction, accidental injury, and respiratory failure due to pneumonia/congestive heart failure. Expected deaths based on U.S. death rates of white males, adjusted for age and calendar year, are 9.2 based on U.S. rates (standardized mortality ratio = 0.41). Subsequent to 1987, three additional deaths occurred from atherosclerotic heart disease, lung cancer, and osteogenic sarcoma. The bone sarcoma case is discussed in terms of Pu exposure, the natural incidence of this disease, anatomical location of the tumor, and bone tumors observed in Pu-exposed dogs. Plutonium deposition in this man is estimated to have been below current radiation protection guidelines.

Aged↗