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PubMed2005

Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part I. Fire experiments.

Controlled burning of experimental plots of forest or grassland in the Chernobyl exclusion zone has been carried out in order to estimate the parameters of radionuclide resuspension, transport and deposition during forest and grassland fires and to evaluate the working conditions of firemen. An increase of several orders of magnitude of the airborne radionuclide concentration was observed in the territory near the fire area. The resuspension factor for (137)Cs and (90)Sr was determined to range from 10(-6) to 10(-5) m(-1), and for the plutonium radionuclides from 10(-7) to 10(-6) m(-1) (related to the nuclides in the combustible biomass). These values are 2 orders of magnitude lower if they are calculated relatively to the total contamination density (including the nuclides in the soil). The radionuclide fallout along the plume axis is negligible in comparison to the existing contamination. However, the additional inhalation dose for firemen exposed in the affected area can reach the level of the additional external irradiation in the period of their mission. The plutonium nuclides constitute the dominating contribution to the inhalation dose.

Adult↗
PubMed2006

Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river's drainage basin.

Sedimentary material from coastal and nearshore areas in the Mississippi Delta region are comprised of different organic carbon sources with diverse ages that require isotopic and elemental records for resolving the various sources of plant residues. Carbon isotopic ((13)C, (14)C) values were used to differentiate contributions from plants using the C3, C4, and/or CAM (crassulacean acid metabolism) carbon fixation pathways., and iodine concentrations indicated that wetland plant residues are a significant source of organic carbon in a sediment core from the Mississippi River delta region collected at a 60 m water depth. This sediment core had been extensively described in Oktay et al. [Oktay, S.D., Santschi, P.H., Moran, J.E., Sharma, P., 2000. The (129)Iodine Bomb Pulse Recorded in Mississippi River delta Sediments: Results from Isotopes of I, Pu, Cs, Pb, and C. Geochim. Cosmochim. Acta 64 (6), 989-996.] and significantly, includes unique features that had not previously been seen in the marine environment. These special features include a plutonium isotopic close-in fallout record that indicates a purely terrestrial source for these sediment particles and the elements associated with it, and a distinct iodine isotopic peak (as well as peaks for plutonium and cesium isotopes) that indicate little bioturbation in this core. Our carbon isotopic and iodine data can thus be compared to published records of changes in drainage basin land use, river hydrology, and hydrodynamic sorting of suspended particles to elucidate if these changes are reflected in nearshore sediments. This comparison suggests a significant contribution for organic carbon (OC) from C4 plants to these sediments during the 1950's to early 1960's. Relative older carbon isotopes, and episodically high iodine concentrations (up to 34 ppm) were observed during this time period that (1) indicate sediment deposition that is coincident with the times of major hydrological changes induced from dam and levee building in both the upper and lower reaches of the Mississippi River drainage basin, and (2) suggest episodic organic carbon deposition from wetland plant residues.

Carbon Isotopes↗
PubMed2001

Improved determination of tributyl phosphate degradation products (mono- and dibutyl phosphates) by ion chromatography.

Tributyl phosphate (TBP) is a very important compound in the nuclear industry, particularly in the area of nuclear fuel reprocessing. This compound is used in the PUREX (plutonium and uranium refining extraction) process which consists of the extraction of uranium and plutonium from an aqueous nitric acid phase, for the purpose of recycling. But TBP may be degraded to dibutyl phosphate (DBP) and monobutyl phosphate (MBP) by dealkylation of one or two butoxy groups, respectively. We have compared and evaluated the capacity of two resins manufactured by Dionex (AS11 and AS5A) in the separation and measurement of these two degradation products. AS11 generates two interferences: nitrite/DBP and carbonate/MBP. The first one is the most serious. So, we have developed a method for oxidising nitrite ions to nitrate ions which have no trouble over the measurement. The second resin tested, AS5A, allows a very efficient separation between DBP and NO2- ions and a good separation between MBP and CO3(2-) in comparison with the AS11. The detection limits for the AS5A column are 0.13 microM for MBP and 0.71 microM for DBP (injection loop=50 microl).

Calibration↗
PubMed1985

The metabolism of radiohafnium in marmosets and hamsters.

The whole body retention of 181Hf was studied in marmosets (Callithrex jacchus) and found to be closely similar to that in rats and Chinese hamsters. Limited tissue distribution studies suggest a higher uptake in liver and much lower deposition in skin and muscle in the marmoset as compared to the rat or Chinese hamster. Studies in Chinese hamsters showed that treatment with the chelating agent diethylenetriaminepentaacetic acid resulted in only a small reduction in the whole body retention of 181Hf. The absorption of orally administered 181Hf, in various chemical forms, was found to be between 0.04 and 0.13% of the ingested dose and was unaffected by age between 5 and 21 months but was increased by fasting. The measured absorption of 181Hf in Chinese hamsters and in rats was similar to that of plutonium suggesting that radiohafnium could be used as a surrogate for plutonium for selected studies in human volunteers.

Animals↗
PubMed2004

Multitracer study of anthropogenic contamination records in the Camargue, Southern France.

Contaminants are supplied to the coastal zone by the atmosphere, rivers and point sources like wastewaters or industrial area. Wetlands retain many of these contaminants and can be used to reconstruct sources and magnitudes of contaminant inputs. Radionuclides ((137)Cs, (210)Pb, (239)Pu and (240)Pu) and stable lead isotope ((206)Pb, (207)Pb) profiles were investigated in two cores collected in wetlands of the Rhône River delta, south of France (Camargue), to estimate the recent sediment accumulation rates and reconstruct the deposition of pollutants during the last century. One site was affected by storm or flood deposition from the Rhône river and showed the influence of Marcoule reprocessing plant releases on the plutonium isotopic ratios. The other site appears suitable for the reconstruction, even if mixing is evidenced at the surface by the radionuclides profiles. Plutonium isotopic ratios are characteristic of global fallout and the (210)Pb inventory of 4240 Bq m(-2) is approximately 30% higher than atmospheric deposit estimation. The pollutant lead inventory is 139 microg cm(-2), slightly higher than previous estimation from direct fallout. This difference can be partly due to an over-collection at this site (due to canopy cover) but also to variations with time in the deposition.

Journal Article↗
PubMed2001

Integrating workplace exposure databases for occupational medicine services and epidemiologic studies at a former nuclear weapons facility.

We outline methods for integrating epidemiologic and industrial hygiene data systems for the purpose of exposure estimation, exposure surveillance, worker notification, and occupational medicine practice. We present examples of these methods from our work at the Rocky Flats Plant--a former nuclear weapons facility that fabricated plutonium triggers for nuclear weapons and is now being decontaminated and decommissioned. The weapons production processes exposed workers to plutonium, gamma photons, neutrons, beryllium, asbestos, and several hazardous chemical agents, including chlorinated hydrocarbons and heavy metals. We developed a job exposure matrix (JEM) for estimating exposures to 10 chemical agents in 20 buildings for 120 different job categories over a production history spanning 34 years. With the JEM, we estimated lifetime chemical exposures for about 12,000 of the 16,000 former production workers. We show how the JEM database is used to estimate cumulative exposures over different time periods for epidemiological studies and to provide notification and determine eligibility for a medical screening program developed for former workers. We designed an industrial hygiene data system for maintaining exposure data for current cleanup workers. We describe how this system can be used for exposure surveillance and linked with the JEM and databases on radiation doses to develop lifetime exposure histories and to determine appropriate medical monitoring tests for current cleanup workers. We also present time-line-based graphical methods for reviewing and correcting exposure estimates and reporting them to individual workers.

Colorado↗
PubMed2003

Regulation of maternal transcript destabilization during egg activation in Drosophila.

In animals, the transfer of developmental control from maternal RNAs and proteins to zygotically derived products occurs at the midblastula transition. This is accompanied by the destabilization of a subset of maternal transcripts. In Drosophila, maternal transcript destabilization occurs in the absence of fertilization and requires specific cis-acting instability elements. We show here that egg activation is necessary and sufficient to trigger transcript destabilization. We have identified 13 maternal-effect lethal loci that, when mutated, result in failure of maternal transcript degradation. All mutants identified are defective in one or more additional processes associated with egg activation. These include vitelline membrane reorganization, cortical microtubule depolymerization, translation of maternal mRNA, completion of meiosis, and chromosome condensation (the S-to-M transition) after meiosis. The least pleiotropic class of transcript destabilization mutants consists of three genes: pan gu, plutonium, and giant nuclei. These three genes regulate the S-to-M transition at the end of meiosis and are thought to be required for the maintenance of cyclin-dependent kinase (CDK) activity during this cell cycle transition. Consistent with a possible functional connection between this S-to-M transition and transcript destabilization, we show that in vitro-activated eggs, which exhibit aberrant postmeiotic chromosome condensation, fail to initiate transcript degradation. Several genetic tests exclude the possibility that reduction of CDK/cyclin complex activity per se is responsible for the failure to trigger transcript destabilization in these mutants. We propose that the trigger for transcript destabilization occurs coincidently with the S-to-M transition at the end of meiosis and that pan gu, plutonium, and giant nuclei regulate maternal transcript destabilization independent of their role in cell cycle regulation.

Animals↗
PubMed2003

Practical system to detect and assess consequences of radioactivity in a wound.

Any wound received within the controlled areas of Dounreay could potentially be contaminated with plutonium and/or uranium isotopes. Wounding bypasses the body's natural barriers to foreign objects, such as the skin and the lining of the alimentary canal. Therefore a relatively low intake can potentially result in a high committed effective dose. The likelihood of contamination of a wound with either plutonium or uranium is low. The decision-making process for dealing with wounds has been continually reviewed and updated by the approved dosimetry service (ADS) at Dounreay. Each wound is considered on an individual basis by the ADS in order to decide what follow-up actions, if any, are necessary. The aim of the process is to maximise the probability that a significant intake is detected, while targeting resources in an appropriate manner.

Decontamination↗
PubMed2003

Effect of DTPA on the nephrotoxicity induced by uranium in the rat.

The only treatment proposed after human contamination with MOX (mixed oxide of uranium and plutonium) is diethylenetriaminepentaacetic acid (DTPA), because plutonium is considered to be the major risk. However, both DTPA and uranium are nephrotoxic at high dosages and DTPA has been shown to increase in vitro the cytotoxicity induced by uranium on cultured epithelial tubular cells. This work aimed to test this effect in vivo. Rats were injected with subtoxic (57 microg kg(-1)) to toxic (639 microg kg(-1)) amounts of uranium as nitrate at 0 h, they received two DTPA injections (30 micromol kg(-1)) at 2 min and 24 h and were euthanased at 48 h. The nephrotoxic effects were evaluated by measurement of the body weight gain, food and water intake, measurement of biochemical parameters in urine and blood, and histological examination of one kidney. The main result was that DTPA did not increase the nephrotoxicity induced by uranium in the range of concentrations tested, which was inconsistent with the in vitro results.

Animals↗
PubMed2004

Methodology for worker neutron exposure evaluation in the PDCF facility design.

A project headed by Washington Group International is meant to design the Pit Disassembly and Conversion Facility (PDCF) to convert the plutonium pits from excessed nuclear weapons into plutonium oxide for ultimate disposition. Battelle staff are performing the shielding calculations that will determine appropriate shielding so that the facility workers will not exceed target exposure levels. The target exposure levels for workers in the facility are 5 mSv y(-1) for the whole body and 100 mSv y(-1) for the extremity, which presents a significant challenge to the designers of a facility that will process tons of radioactive material. The design effort depended on shielding calculations to determine appropriate thickness and composition for glove box walls, and concrete wall thicknesses for storage vaults. Pacific Northwest National Laboratory (PNNL) staff used ORIGEN-S and SOURCES to generate gamma and neutron source terms, and Monte Carlo (computer code for) neutron photon (transport) (MCNP-4C) to calculate the radiation transport in the facility. The shielding calculations were performed by a team of four scientists, so it was necessary to develop a consistent methodology. There was also a requirement for the study to be cost-effective, so efficient methods of evaluation were required. The calculations were subject to rigorous scrutiny by internal and external reviewers, so acceptability was a major feature of the methodology. Some of the issues addressed in the development of the methodology included selecting appropriate dose factors, developing a method for handling extremity doses, adopting an efficient method for evaluating effective dose equivalent in a non-uniform radiation field, modelling the reinforcing steel in concrete, and modularising the geometry descriptions for efficiency. The relative importance of the neutron dose equivalent compared with the gamma dose equivalent varied substantially depending on the specific shielding conditions and lessons were learned from this effect. This paper addresses these issues and the resulting methodology.

Algorithms↗
PubMed2005

Modern new nuclear fuel characteristics and radiation protection aspects.

The glut of fissile material from reprocessing plants and from the conclusion of the cold war has provided the opportunity to design new fuel types to beneficially dispose of such stocks by generating useful power. Thus, in addition to the normal reactor core complement of enriched uranium fuel assemblies, two other types are available on the world market. These are the ERU (enriched recycled uranium) and the MOX (mixed oxide) fuel assemblies. Framatome ANP produces ERU fuel assemblies by taking feed material from reprocessing facilities and blending this with highly enriched uranium from other sources. MOX fuel assemblies contain plutonium isotopes, thus exploiting the higher neutron yield of the plutonium fission process. This paper describes and evaluates the gamma, spontaneous and alpha reaction neutron source terms of these non-irradiated fuel assembly types by defining their nuclear characteristics. The dose rates which arise from these terms are provided along with an overview of radiation protection aspects for consideration in transporting and delivering such fuel assemblies to power generating utilities.

Materials Testing↗
PubMed1995

Potential effects of surface water components on actinide determinations conducted by ion chromatography.

An elution program for separating actinides (thorium, uranium, neptunium, plutonium, americium, and curium) on low hydrophobicity ion exchange columns was evaluated for solutions spiked with actinides and common surface water components. Potential interferences from dissolved ions (Na+, K+, Ca2+, Cl-, and SO(4)2-), humic acid, and radium were investigated. Sulfate levels greater than 0.25 mumol interfered with separation of americium, curium, and plutonium. Humic acid levels above 100 micrograms produced distinct widening of actinide peaks and reduced actinide recoveries. These interferences limit the range of useful sample volumes and create a need for sample pretreatment procedures. No interferences were produced by 0.025 to 2.5 mumol Ca2+, 0.045 to 4.5 mumol Na+, 0.015 to 1.5 mumol K+, and 0.025 to 4.5 mumol Cl-. In the absence of interferences, the program effectively separated radium from the actinides.

Actinoid Series Elements↗
PubMed1997

University of Washington's radioecological studies in the Marshall Islands, 1946-1977.

Since 1946, personnel from the School of Fisheries, University of Washington (Applied Fisheries Laboratory, 1943-1958; Laboratory of Radiation Biology, 1958-1967; and Laboratory of Radiation Ecology, since 1967), have studied the effects of nuclear detonations and the ensuing radioactivity on the marine and terrestrial environments throughout the Central Pacific. A collection of reports and publications about these activities plus a collection of several thousand samples from these periods are kept at the School of Fisheries. General findings from the surveys show that (1) fission products were prevalent in organisms of the terrestrial environment whereas activation products were prevalent in marine organisms; (2) the best biological indicators of fallout radionuclides by environments were (a) terrestrial-coconuts, land crabs; (b) reef-algae, invertebrates; and (c) marine-plankton, fish. Studies of plutonium and americium in Bikini Atoll showed that during 1971-1977 the highest concentrations of 241Am, 2.85 Bq g(-1) (77 pCi g(-1)) and 239,240Pu, 4.44 Bq g(-1) (120 pCi g(-1)), in surface sediments were found in the northwest part of the lagoon. The concentrations in the bomb craters were substantially lower than these values. Concentrations of soluble and particulate plutonium and americium in surface and deep water samples showed distributions similar to the sediment samples. That is, the highest concentration of these radionuclides in the water column were at locations with highest sediment concentration. Continuous circulation of water in the lagoon and exchange of water with open ocean resulted in removal of 111 G Bq y(-1) (3 Ci y(-1)) 241Am and 222 G Bq y(-1) (6 Ci y(-1)) 239,240Pu into the North Equatorial Current. A summary of the surveys, findings, and the historical role of the Laboratory in radioecological studies of the Marshall Islands are presented.

Animals↗
PubMed1988

Mortality of employees of the Atomic Weapons Establishment, 1951-82.

A total of 22,552 workers employed by the Atomic Weapons Establishment between 1951 and 1982 were followed up for an average of 18.6 years. Of the 3115 who died, 865 (28%) died of cancer. Mortality was 23% lower than the national average for all causes of death and 18% lower for cancer. These low rates were consistent with the findings in other workforces in the nuclear industry and reflect, at least in part, the selection of healthy people to work in the industry and the disproportionate recruitment of people from the higher social classes. At some time during their employment 9389 (42%) of the workers were monitored for exposure to radiation, the average cumulative whole body exposure to external radiation being 7.8 mSv. Their mortality was generally similar to that of other employees, even when exposures were lagged by 10 years. The rate ratio after a 10 year lag in workers with a radiation record compared with other workers was 1.01 (95% confidence interval 0.92 to 1.10) for all causes of death and 1.06 (0.89 to 1.27) for all malignant neoplasms. The only significant differences were for prostatic cancer (rate ratio 2.23; 95% confidence interval 1.13 to 4.40) and for cancers of ill defined and secondary sites (rate ratio 2.37; 1.23 to 4.56). Cancers of lymphatic and haemopoietic tissues were notable for their low occurrence in the study population, with only four deaths from leukaemia and two from multiple myeloma in workers with a radiation record, 9.16 and 3.55 deaths respectively being expected on the basis of national rates. Among workers who had a radiation record 3742 (40%) were also monitored for possible internal exposure to plutonium, 3044 (32%) to uranium, 1562 (17%) to tritium, 638 (7%) to polonium, and 281 (3%) to actinium. In these workers mortality from malignant neoplasms as a whole was not increased, but after a 10 year lag death rates from prostatic and renal cancers were generally more than twice the national average, these excesses arising in a small group of workers monitored for exposure to multiple radionuclides. Though mortality from lung cancer in workers monitored for exposure to plutonium was below the national average, it was some two thirds higher than in other radiation workers, the excess being of borderline statistical significance. Mortality from malignant neoplasms as a whole showed a weak and non-significant increasing trend with increasing level of cumulative whole body exposure to external radiation. When the exposures were lagged by 10 years the trend became stronger and significant, the estimated increase in relative risk per 10 mSv being 7.6% (95% confidence interval 0.4% to 15.3%). This trend was confined almost entirely to workers who were also monitored for exposure to radionuclides (p<0.001), the main contributions coming from lung cancer and prostatic cancer. Exposures of the lung and prostate from internal sources of radiation were not quantified, except for the contribution from tritium. It was therefore not possible to assess the extent to which the associations were due to internally deposited radionuclides rather than external exposure. The finding for prostatic cancer taken in conjunction with the results of other studies suggest a specific occupational hazard in a small group of workers in the nuclear industry who had comparatively high exposures to external radiation and who were also monitored for internal exposure to multiple radionuclides. Research is needed to discover whether any of the radionuclides and other substances concerned are concentrated in the prostate. The occurrence of lung cancer in this workforce requires further investigation taking into account smoking habits and tissue doses from inhaled radionuclides.

Cardiovascular Diseases↗
PubMed1997

Alterations in the K-ras and p53 genes in rat lung tumors.

Activation of the K-ras protooncogene and inactivation of the p53 tumor suppressor gene are events common to many types of human cancers. Molecular epidemiology studies have associated mutational profiles in these genes with specific exposures. The purpose of this paper is to review investigations that have examined the role of the K-ras and p53 genes in lung tumors induced in the F344 rat by mutagenic and nonmutagenic exposures. Mutation profiles within the K-ras and p53 genes, if present in rat lung tumors, would help to define some of the molecular mechanisms underlying cancer induction by various environmental agents. Pulmonary adenocarcinomas or squamous cell carcinomas were induced by tetranitromethane (TNM), 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK), beryllium metal, plutonium-239, X-ray, diesel exhaust, or carbon black. These agents were chosen because the tumors they produced could arise via different types of DNA damage. Mutation of the K-ras gene was determined by approaches that included DNA transfection, direct sequencing, mismatch hybridization, and restriction fragment length polymorphism analysis. The frequency for mutation of the K-ras gene was exposure dependent. Only two agents, TNM and plutonium, led to mutation frequencies of > 10%. In both cases, the transition mutations formed could have been derived from deamination of cytosine. The identification of non-ras transforming genes in rat lung tumors induced by mutagenic and nonmutagenic exposures such as NNK and beryllium would help define some of the mechanisms underlying cancer induction by different types of DNA damage. Alteration in the p53 gene was assessed by immunohistochemical analysis for p53 protein and single-strand conformation polymorphism (SSCP) analysis of exons 4 to 9. None of the 93 adenocarcinomas examined was immunoreactive toward the anti-p53 antibody CM1. In contrast, 14 to 71 squamous cell carcinomas exhibited nuclear p53 immunoreactivity with no correlation to type of exposure. However, SSCP analysis only detected mutations in 2 of 14 squamous cell tumors that were immunoreactive, suggesting that protein stabilization did not stem from mutations within the p53 gene. Thus, the p53 gene does not appear to be involved in the genesis of most rat lung tumors.

Animals↗
PubMed1997

The Russian radiation legacy: its integrated impact and lessons.

Information about the consequences of human exposure to radiation in the former Soviet Union has recently become available. These data add new insights and provide possible answers to several important questions regarding radiation and its impact on occupational and public health. The 1986 Chernobyl accident initiated a major and early increase in childhood thyroid cancer that resulted from ingestion of iodine-131 (131I) by young children living in the most heavily contaminated areas of Belarus, Ukraine, and Russia. No significant additional cancer or other adverse medical effects have yet been reported in the affected populations and among clean-up workers. Major psychological stress independent of radiation dose has been observed in those people thought to be exposed. During the early days of the atomic energy program in the former Soviet Union, some unfortunate events occurred. The country's first atomic test in Semipalatinsk in 1949 exposed over 25,000 people downwind from the blast to significant doses of fission products, especially 131I. During the late 1940s and the early 1950s nuclear material production facilities were developed near Chelyabinsk in the South Ural Mountains, which resulted in major releases into the environment and significant overexposures for thousands of workers and nearby populations. Chronic radiation sickness was observed early in exposed workers, and increases in leukemia and other cancers were also reported. The series of plutonium inhalation-related lung cancers and fatalities among workers exposed in that first decade appears to be unique. Long-term consequences of chronic radiation sickness and four decades of follow-up are being described for the first time. Villagers downstream from the plant consumed high levels of 137Cs and 90Sr and, it is reported, manifested increases in leukemia from internal and external exposures. Although the 40-year databases for retrospective dosimetry epidemiology studies are just beginning to be integrated and evaluated, preliminary evaluations suggest that there may be graded, significant dose-rate amelioration factors for cancer and leukemia risks in workers and the general population relative to the risk data on the Japanese atomic bomb survivors. Even for plutonium-induced lung cancers in workers, such a dose-rate effect may be evident. These experiences give us insight into the consequences of protracted radiation at high and low doses and rates. If these findings are validated and confirmed, they can provide information that reduces some of the uncertainties in retrospective radiation dosimetry and radiation risk estimates (especially for low-level, chronic exposures) for activities related to medicine as well as the handling of nuclear materials and nuclear facility decommissioning, decontamination, and demilitarization.

Adult↗
PubMed1994

[Evaluation of radiation and non-radiation factors in the development of lung cancer in radiochemical plant employees].

Five hundred workers of a nuclear facility (162 cases of lung cancer and 338 healthy subjects) were examined on a case-control basis using the logical regression method and 10 radiation and non-radiation factors. Five significant factors were identified. The following rick values were obtained for them: tobacco smoking-6.6; plutonium-associated pneumosclerosis-4.6; plutonium incorporation-3.1; chronic non-specific diseases of the lung-2.1 and gamma ray exposure-1.6. Radiation-associated rick was under 25%, while that of non-radiation factors not less than 70%.

Aged↗
PubMed1996

Analytical microscopy and environment. Current developments using bioindicators of pollution by stable and radioactive elements.

Ecotoxicological investigations were performed on three sets of bioindicators. The first one concerns marine pollution of invertebrates (molluscs: the mussel Mytilus edulis and related species, crustaceans: the crab Liocarcinus puber and related species), contaminated by stable or radioactive elements originating from wastes discharged into sea water. The second one concerns freshwater pollution of vertebrates (fish: the brown trout Salmo trutta fario), contaminated by aluminium dissolved in rivers, as a consequence of an atmospheric pollution by acid rain. The third one concerns the atmospheric pollution of trees by plutonium (Casuarina equisetifolia). Mechanisms involved in the uptake, storage and elimination processes of these toxicants were studied, with a special emphasis on cellular and subcellular aspects of concentration sites. Two microanalytical methods were employed: Secondary Ion Mass Spectrometry (SIMS), using the ion microscope and the ion microprobe, and X-ray spectrometry using the electron microprobe (EMP). In marine organisms, the target organs and tissues of bioaccumulation of stable and radioactive elements (238U, 239Pu and 241Am), were shown to be mainly digestive gland, gill and exoskeleton. The target organelles were shown to be spherocrystals and lysosomes. Amoebocytes, enzymatically equipped with lysosomal phosphatase, were involved in the phagocytic clearance of metal pollutants. In trout, insolubilisation of Al phosphate within lysosomes and a high metal concentration within bones were observed. The tree Casuarina equisetifolia exhibits a particular ability to concentrate atmospheric plutonium within its leaves.

Air Pollution↗