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The functional change index was calculated to assess the strain of adaptative mechanisms in inhabitants on the Techa river polluted with radioactive waste. Radiation was shown to have an impact on the strain of adaptative mechanisms, but the degree of this impact was moderate.
After the Chernobyl accident, a National Emergency Plan of protective measures for radiological emergencies has been set up in Italy to cope with nuclear risks which require actions at national level. Since the Italian nuclear power plants are, at present, not operational, the most relevant nuclear risk source identified in the National Emergency Plan is related to an accident occurring in a nuclear power plant near the Italian borders. However, risks related to severe accidents to other nuclear facilities present in Italy, such as provisional radioactive waste deposits or research centers are not taken into account in the Plan. In this paper the hypothetical radiological impact of a severe external event in a spent fuel storage pool has been evaluated, as this event appears to be one of those with the most severe consequences.
The author considered medical consequences of radiation accidents on Industrial Association "Mayak" (radioactive waste discharge into Techa river and accident in 1957). Results of longstanding observations helped to evaluate health state of people exposed to radiation and their descendants.
Quantitative and qualitative analysis of cell cultures labeled with 3H-proline for monitoring collagen synthesis is time-consuming and occasionally generates large quantities of radioactive waste. This present work describes the application of a microwell filtration system for the analysis of collagen metabolism in chondrocytes. It is based on trichloroacetic acid (TCA) precipitation of 3H-proline-labeled proteins onto polyvinylidene difluoride membranes fitted in a 96-well plate and subsequent analysis of precipitated proteins by liquid scintillation counting, amino acid analysis and sodium dodecyl sulfate (SDS) gel electrophoresis. This method allows for the initial processing of 96 samples within 2 h, has high sensitivity and accuracy (linearity > or = 200 cpm/sample) for quantitative measurements and a capacity of up to 10 micrograms collagen/microwell. The ratio of the radioactive protein collected by this filtration assay compared to that collected by molecular sieve chromatography on Sephadex G-25 was linear over a broad range, indicating full compatibility of data and a high reproducibility for both assay systems. The quality of protein separation by SDS-polyacrylamide gel electrophoresis (PAGE) from samples obtained by the filtration assay and by dialysis was virtually identical. These features make the assay particularly suited for pulse-chase experiments and for monitoring protein degradation.
There are many diverse uses of accelerator mass spectrometry (AMS). Carbon-14 studies at our laboratory include much research related to paleoclimate, both with 14C as a tracer of past changes in environmental conditions as observed in corals, marine sediments and many terrestrial records. Terrestrial records such as forest fires can also show the influence of oceanic oscillations, whether they are short-term such as ENSO, or on the millennial time scale. In tracer applications, we have developed the use of 129I as well as 14C as tracers for nuclear pollution studies around radioactive waste dump sites, in collaboration with IAEA. We discuss some applications carried out in Tucson for several of these fields and hope to give some idea of the breadth of these studies.
Anthropogenic plutonium has been introduced into the environment over the past 50 years as the result of the detonation of nuclear weapons and operational releases from the nuclear industry. In the Arctic environment, the main source of plutonium is from atmospheric weapons testing, which has resulted in a relatively uniform, underlying global distribution of plutonium. Previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases have given rise to enhanced local concentrations. Since different plutonium sources are characterised by distinctive plutonium-isotope ratios, evidence of a localised influence can be supported by clear perturbations in the plutonium-isotope ratio fingerprints as compared to the known ratio in global fallout. In Kara Sea sites, such perturbations have been observed as a result of underwater weapons tests at Chernaya Bay, dumped radioactive waste in Novaya Zemlya, and terrestrial runoff from the Ob and Yenisey Rivers. Measurement of the plutonium-isotope ratios offers both a means of identifying the origin of radionuclide contamination and the influence of the various nuclear installations on inputs to the Arctic, as well as a potential method for following the movement of water and sediment loads in the rivers.
The advantages of using radionuclides for laboratory studies of environmental processes include the wide range of element concentrations that can be studied, the capability to simultaneously study several isotopes in a single experiment, the direct applicability to the behaviour of radioactive waste or fallout, and the ability to study the mechanisms, reversibility and kinetics of environmental reactions under controlled conditions. These attributes are demonstrated using specific examples drawn from case studies in Australia, including radionuclide fallout onto tropical soils, the association of trace metals with harbour sediments and the behaviour of uranium in natural and contaminated systems.
A cytogenetic analysis was carried out on a population of Chironomus balatonicus (Chironomidae, Diptera) from Chernobyl, a highly radioactive area of the Kiev region. Several chromosomal aberrations were established unique to a population of Chironomus balatonicus living in an area contaminated by radioactive waste. Five new heterozygous inversions, deficiencies in arms C, D, E, F and chromatid breaks were found in the irradiated population but not in nonirradiated populations. A pericentric inversion in chromosome AB occurred at a relatively high frequency. Genome aberrations expressed by a heterochromatized 'B' chromosome were evident. In the irradiated and nonirradiated populations common inversions occurred showing variation in their frequency depending on specific environmental conditions. The somatic and also the germ cells were characterized by a number of heteropycnotic nuclei and vacuolized chromosomes. Both the somatic and germ cells showed changes in the structural and functional organization of heterochromatin and this was particularly marked in the telomeric sectors of the chromosomes. The heterochromatin which is extremely sensitive to radioactivity appears to protect euchromatin from adverse environmental conditions.
The viability of dental pulp depends largely on regional blood flow, as in other organs. Measurement of absolute pulpal blood flow (PBF) and comparisons with blood flow in other organs allow the prediction of microvascular regulation in dental pulp. In previous studies, PBF was measured in dogs mainly with radioactive microspheres. However, this established technique is inaccessible to many investigators due to concerns over radiation safety and radioactive waste. To overcome these limitations, a new method has been introduced that involves the use of nonradioactive colored microspheres for measuring regional blood flow in the myocardium and in other organs in animals. However, no previous studies have investigated the use of this method to measure PBF in dogs. We attempted to determine whether blood flow in dental pulp, which comprises a small amount of the total tissue in dogs, could be measured using this technique by comparing the measured values with those for regional myocardial blood flow. Mean blood flow values were between 0.148 and 0.182 ml/min/g for dental pulp at four different sites and about 1.0 ml/min/g in regional myocardium. These values are comparable to those previously reported using radioactive microspheres. As nonradioactive colored microspheres safety permitted measurement of absolute PBF in dogs, this technique appears to be useful for research into microvascular blood flow in dental pulp.
Numerous sites in the United States and around the world are contaminated with depleted uranium (DU) in various forms. A prevalent form is fragmented DU originating from various scientific tests involving high explosives and DU during weapon development programs, at firing practice ranges, or war theaters where DU was used in armor-piercing projectiles. The contamination at these sites is typically very heterogeneous, with discreet, visually identifiable DU fragments mixed with native soil. That is, the bulk-averaged DU activity is quite low, while specific DU fragments, which are distinct from the soil matrix, have much higher specific activity. DU is best known as a dark, black metal that is nearly twice as dense as lead, but DU in the environment readily weathers (oxidizes) to a distinctive bright yellow color that is readily visible. While the specific activity (amount of radioactivity per mass of soil) of DU is relatively low and presents only a minor radiological hazard, the fact that it is radioactive and visually identifiable makes it desirable to remove the DU "contamination" from the environment. The typical approach to conducting this DU remediation is to use radiation detection instruments to identify the contaminant and separate it from the adjacent soil, packaging it for disposal as radioactive waste. This process can be performed manually or by specialized, automated equipment. Alternatively, in certain situations a more cost-effective approach might be simple mechanical or gravimetric separation of the DU fragments from the host soil matrix. At SNL/NM, both the automated and simple mechanical approaches have recently been employed. This paper discusses the pros/cons of the two approaches.
An area located in the Southern Urals was contaminated in 1949-1956 as a result of radioactive waste releases into the Techa river by the Mayak Production Association. The external dose reconstruction of the Techa river dosimetry system (TRDS-2000) for the exposed population is based on an assessment of dose rates in air (DRA) obtained by modeling transport and deposition of radionuclides along the river for the time before 1952 and by gamma dose rate measurements since 1952. The aim of this paper is to contribute to a verification of the TRDS-2000 external dose assessment. Absorbed doses in bricks from a 130-year-old building in the heavily exposed Metlino settlement were measured by a luminescence technique. By the autumn of 1956 the population of Metlino had been evacuated, and then a water reservoir was created at the village location, which led to a change in the radioactive source geometry. Radiation transport calculations for assumed environmental sources before and since 1957 were performed with the MCNP Monte Carlo code. In combination with TRDS-2000 estimates for annual dose rates in air at the shore of the Techa river for the period 1949-1956 and contemporary dose rate in air measurements, absorbed doses in bricks were calculated. These calculations were performed deterministically with best estimates of the modeling parameters and stochastically by propagating uncertainty distributions through the calculation scheme. Assessed doses in bricks were found to be consistent with measured values within the uncertainty bounds, while their best estimates were approximately 15% lower than the luminescence measurements.
Transfer factors have been measured for 239 Pu + 240 Pu, 241 Am, 90 Sr and 137 Cs into potatoes grown in a blend of soil which included silt polluted with radioactive waste discharged into the Irish Sea. The experiment has been carried out over four seasons and attempts to assess the radiological consequences to the consumer which would arise if potatoes were to be grown in land heavily contaminated with the silt. During the course of the experiment plutonium and americium became less available for uptake, 90 Sr became slightly more available and 137 Cs remained nearly constant in its availability. The values of the transfer factors are among the lowest reported for these radionuclides into potatoes.
The roles of science, ethics and politics are identified in respect of the risks of exposure to low-dose radiation. Two case studies, the epidemiology of the United Kingdom nuclear test veterans and the risks to civilians associated with the military use of depleted uranium, are considered in the context of their ethical framing, scientific evaluation and political resolution. Two important issues for the present and future, the safe management of U.K. radioactive waste and the future of nuclear power, in which the science of low dose effects will be crucial and where the ethical issues are much more complex, are introduced. Specific consideration is given to the potential hereditary effects of ionising radiation in relation to the current state of radiobiological knowledge. It is concluded that for science to be useful in public health policy making there needs to be some reform from within the profession and the political imperative for freely independent scientific institutions.
A study (N=198) was conducted to examine hypotheses derived from an emotion-based model of stigma responses to radiation sources. A model of stigma susceptibility is proposed in which affective reactions and cognitive worldviews activate predispositions to appraise and experience events in systematic ways that result in the generation of negative emotion, risk perceptions, and stigma responses. Results of structural equation modeling supported the hypotheses. Radiation sources that scored higher on a measure of stigma were included in the analyses (i.e., nuclear power plants, radioactive waste from nuclear power plants, radiation from nuclear weapons testing). Individual differences in negative reactivity and worldviews were associated with the strength of emotional appraisals that were associated, in turn, with negative emotion toward stigmatized radiation sources. As hypothesized, the model fit better with perceived risk as a function of negative emotion rather than vice versa. Finally, a measure of stigma was associated with negative emotion and, to a lesser extent, with risk perceptions. Risk communication about stigmatized objects may benefit from a more complete understanding of how affective and emotional reactions are constructed and the routes through which they affect responses and behaviors.
An analysis of tritium and 36Cl data collected at Yucca Mountain, Nevada suggests that fracture flow may occur at high velocities through the thick unsaturated zone. The mechanisms and extent of this "fast flow" in fractures at Yucca Mountain are investigated with data analysis, mixing models and several one-dimensional modeling scenarios. The model results and data analysis provide evidence substantiating the weeps model [Gauthier, J.H., Wilson, M.L., Lauffer, F.C., 1992. Proceedings of the Third Annual International High-level Radioactive Waste Management Conference, vol. 1, Las Vegas, NV. American Nuclear Society, La Grange Park, IL, pp. 891-989] and suggest that fast flow in fractures with minimal fracture-matrix interaction may comprise a substantial proportion of the total infiltration through Yucca Mountain. Mixing calculations suggest that bomb-pulse tritium measurements, in general, represent the tail end of travel times for thermonuclear-test-era (bomb-pulse) infiltration. The data analysis shows that bomb-pulse tritium and 36Cl measurements are correlated with discrete features such as horizontal fractures and areas where lateral flow may occur. The results presented here imply that fast flow in fractures may be ubiquitous at Yucca Mountain, occurring when transient infiltration (storms) generates flow in the connected fracture network.
The Great Lakes basin is of radiologic interest due to the large population within its boundaries that may be exposed to various sources of ionizing radiation. Specific radionuclides of interest in the basin arising from natural and artificial sources include 3H, 14C, 90Sr, 129I, 131I, 137Cs, 222Rn, 226Ra, 235U, 238U, 239Pu, and 241Am. The greatest contribution to total radiation exposure is the natural background radiation that provides an average dose of about 2.6 mSv/year to all basin residents. Global fallout from atmospheric nuclear weapons tests conducted before 1963 has resulted in the largest input of anthropogenic radioactivity into the lakes. Of increasing importance is the radionuclide input from the various components of the nuclear fuel cycle. Although the dose from these activities is currently very low, it is expected to increase if there is continued growth of the nuclear industry. In spite of strict regulations on design and operation of nuclear power facilities, the potential exists for a serious accident as a result of the large inventories of radionuclides contained in the reactor cores; however, these risks are several orders of magnitude less than the risks from other natural and man-made hazards. An area of major priority over the next few decades will be the management of the substantial amounts of radioactive waste generated by nuclear fuel cycle activities. Based on derived risk coefficients, the theoretical incidence of fatal and weighted nonfatal cancers and hereditary defects in the basin's population, attributable to 50 years of exposure to natural background radiation, is conservatively estimated to be of the order of 3.4 x 10(5) cases. The total number of attributable health effects to the year 2050 from fallout radionuclides in the Great Lakes basin is of the order of 5.0 x 10(3). In contrast, estimates of attributable health effects from 50 years of exposure to current nuclear fuel cycle effluent in the basin are of the order of 2 x 10(2). Although these are hypothetical risks, they show that the radiologic impact of man-made sources is very small compared to the effects of normal background radiation.
The distribution between hardened cement paste and cement pore water of selected concrete admixtures (BZMs), i.e., sulfonated naphthalene-formaldehyde condensate (NS), lignosulfonate (LS) and a gluconate-containing plasticiser used at the Paul Scherrer Institute for waste conditioning, was measured. Sorption data were fitted to a single-site Langmuir isotherm with affinity constants K=(19+/-4)dm(3)g(-1) for NS, K=(2.1+/-0.6) dm(3)g(-1) for LS and sorption capacities q=(81+/-16)g kg(-1) for NS, q=(43+/-8)g kg(-1) for LS. In the case of gluconate, a two-site Langmuir sorption model was necessary to fit the data satisfactorily. Sorption parameters for gluconate were K(1)=(2+/-1)x10(6)dm(3)mol(-1) and q(1)=(0.04+/-0.02)mol kg(-1) for the stronger binding site and K(2)=(2.6+/-1.1)x10(3)dm(3)mol(-1) and q(2)=(0.7+/-0.3)mol kg(-1) for the weaker binding site. Desorption of these BZMs from cement pastes and pore water in cement specimens prepared in the presence of the BZMs were then used to test the model. It was found that only minor parts of NS and LS could be mobilised as long as the cement composition was intact, whereas the sorption of gluconate was found to be reversible. The Langmuir model makes valuable predictions in the qualitative sense in that the pore water concentration of the BZMs is reduced by several orders of magnitude as compared to the initial concentrations. In view of the necessity for conservative predictions used in the safety analysis for disposal of radioactive waste, however, the predictions are unsatisfactory in that the measured pore water concentrations of NS and LS were considerably larger than the predicted values. This conclusion does not apply for gluconate, because its concentration in cement pore water was below the detection limit of approximately 50 nM.
Sorption is an important process for the transport of radionuclides through backfill materials in a radioactive waste underground repository. Within this study, sorption of Cs on selected Czech clay materials and their mixtures with sand was investigated by batch tests. The experiments were performed under oxic conditions at 25 degrees C. Synthetic groundwater as a liquid phase and unconditioned clays (as they were provided by their producer) were used to reach the natural conditions as close as possible. Distribution ratios (Rds) of Cs for all selected clays rise with increase of the clay fraction in clay/sand mixtures in agreement with previous works studying sorption behaviour of such mixtures. The rise of Rds is from 10(2) cm3 g(-1) for mixtures with 80% of sand to 10(3) cm3 g(-1) for pure clays. There are significant differences between natural and technologically modified clays.