Results 1 - 10 of 138
Results 1 - 10 of 138. Search took: 0.022 seconds
|Sort by: date | relevance|
[en] This short paper describes a number of investigations carried out to ensure preparedness for crises involving radioactivity to catering operations and private households in Finland. The specific recommendations for catering kitchens during crises were published in 1994. A study to determine the level of adherence to these recommendations is summarised here, together with its findings and subsequent recommendations. Another study on the pre-planning of crisis menus is described. New challenges for the catering kitchens are touched upon. A crisis food preparation booklet for households is described and based on consumers' attitudes suggestions are made for how this can be improved in the future
[en] The radiation protection community has only recently started the important work of preparedness for long-term post-accidental management of radioactively contaminated areas, like for instance the EC projects STRATEGY, FARMING and EURANOS and the French authorities' CODIRPA and PAREX programmes. There are, however, different views concerning how long a long-term management might last. Based on the Norwegian and former Soviet Union experience after the Chernobyl accident, it is clear that a nuclear accident can entail decades of necessary management and rehabilitation of living conditions. The time period is dependent on a number of factors, e.g. amount of fallout, type of radionuclides, land use of contaminated area, number and density of people affected and available techniques and resources for implementing countermeasures. This paper discusses the management strategy implemented in Norway after the Chernobyl accident, the need for changing strategy over time and the important involvement of affected groups. Careful planning and reflections should be undertaken before actions are taken in the recovery phase, keeping in mind the possibility of decades with problems.
[en] Lake sediment cores and samples of stream sediments from the catchment of Oevre Heimdalsvatn have been collected. The lake sediments exhibit apparently unsystematic spatial distribution of radiocaesium. This is ascribed to irregular bathygraphy. However, the radiocaesium concentration increased with increasing percentage of organic matter, water content, and with distance from the main inlet. There was no correlation with lake depth. Stream sediments were scarce because of torrential conditions but those present had activities in line with the lake sediments. Therefore they constitute a small potential for further supply of radiocaesium to the lake. Measurements of export from the catchment and retention in the lake show that the total radiocaesium activity in the sediments may remain unchanged or even increase during the years to come. (author)
[en] The EC FARMING network (Food and Agriculture Restoration Management Involving Networked Groups) was set up to bring together the many and diverse stakeholders who would be involved in intervention following wide scale radioactive contamination of the food chain, so that acceptable strategies can be developed for maintaining agricultural production and safe food supply. The network comprises stakeholder panels in the UK, Finland, Belgium, France and Greece that have met regularly since 2001 to debate, discuss and exchange opinion on the acceptability, constraints and impact of various countermeasure options and strategies. The objectives of this paper are to consolidate the main achievements of the FARMING project over the period 2000-2004, to highlight the various difficulties that were encountered and to discuss the challenges for engaging stakeholders in off-site emergency management and long-term rehabilitation in the future
[en] Discussions at the national level about critical infrastructure and its vulnerability are more common now following the events of September 11. The National Emergency Supply Agency organised a training exercise to test the logistics of food supply following passage of a plume containing radioactive material over a district in Finland. This short paper summarises the problems that had to be faced and suggests a way forward for improving emergency preparedness in this area
[en] Most Pu from nuclear fallout is currently found in surface soils from which it is distributed by migration, resuspension and uptake by the roots of plants. This paper investigates the sites of localization of Pu in plants and examines which parameters determine its uptake. Different species of trees were studied, special attention being directed towards seasonal variations of Pu uptake in different parts of the plants. To differentiate between Pu adsorption and absorption, the plant parts were washed with CHCl3. Most of the Pu was found in the bark, being adsorbed on the plant surface. Comparison of Pu concentrations in plants over several years shows a constant decrease similar to that observed in air. (author)
[en] The sorption behaviour of caesium in 19 different soils from various regions of Sweden and Libya was studied in batch experiments. All experiments were carried out in the presence of a supporting electrolyte (0.01 N CaC12). The experimental treatments were varying concentrations of Cs+ from 0.03 to 0.767 meq/litre, and one level of K+ and NH4+, 100 meq/litre. The sorption behaviour of caesium was complex. The distribution coefficient, the Kd value, was strongly reduced after small additions of stable caesium. However, at increasing concentrations of stable caesium the effect became much less. Also, when potassium and ammonium were present in the experimental environment, the caesium sorption capacity of the soils was reduced. It was also found that the clay content in the soils strongly influenced the sorption of caesium as shown by the Kd values. Some of the Libyan soils showed higher Kd values than the Swedish soils with similar clay content. The data available and the relationships found for the 19 soils were used in the development of simple mathematical models for prediction of transfer factors for caesium to wheat. (Author)
[en] The amount and vertical distribution of Chernobyl-derived 137Cs in the bottom sediments of some Finnish lakes were studied. Sediment and surface water samples were taken in 2000 and 2003 from 12 stations in nine lakes and the results were compared with those obtained in corresponding surveys carried out in 1969, 1978, 1988 and 1990. Each of the five deposition categories of Chernobyl fallout in Finland were represented. The depth profiles of 137Cs in the sediments showed considerable variety in the lakes studied. The peak values varied between 1.5 and 46 kBq kg-1 dry wt. The size and shape of the peak did not always correlate with the amount of deposition in the area, but on the other hand, reflected differences in sedimentation processes in different lakes. In some of the lakes the peak still occurred in the uppermost (0-2 cm) sediment layer, but in an extreme case the peak occurred at a depth of 22-23 cm corresponding to a sedimentation rate of 16 mm year-1 during the 14 years after the Chernobyl accident. The total amounts of 137Cs in sediments varied from 15 to 170 kBq m-2 at the sampling stations studied. Since 1990, the amounts have continued to increase slightly in two lakes, but started to decrease in the other lakes. In most of the lakes, the total amounts of 137Cs in sediments were about 1.5-2 times higher than in local deposition. In two lakes, the ratio was below 1, but in one case 3.2. Compared with the total amounts of 137Cs at the same stations in the late 1960s and 1970s, the values were now at their highest, at about 60-fold. The most important factors affecting 137Cs values in sediments were the local amount of deposition and the type of the lake and the sediment, but in addition, there were a number of other factors to be considered
[en] Aerosol samples collected in 1989 and 1990 at Vardo (north Norway) were analysed for thorium, uranium and plutonium. The mean activity concentrations found for 232Th, 238U, 239,240Pu and 238Pu were 65, 68, 0.68 and 0.077 nBq m-3, respectively. The results are compared with the relevant data from north Germany. The 232Th and 238U activity concentrations are less, by one order of magnitude, than activity concentrations in north Germany - not only due to the lower dust content but also to the lower specific activity of the inorganic aerosol components. The 238Pu/239,240Pu and 239,240Pu/137Cs activity ratios are comparable with those found in aerosols from north Germany. There are no indications of regional sources of plutonium aerosols. (Author)
[en] In environmental risk assessments of nuclear waste, there is need to estimate the potential risks of a large number of radionuclides over a long time period during which the environment is likely to change. Usually concentration ratios (CRs) are used to calculate the activity concentrations in organisms. However, CRs are not available for all radionuclides and they are not easily scalable to the varying environment. Here, an ecosystem transport model of elements, which estimates concentrations in organisms using carbon flows and food transfer instead of CR is presented. It is a stochastic compartment model developed for Lake Eckarfjärden at Forsmark in Sweden. The model was based on available data on carbon circulation, physical and biological processes from the site and identifies 11 functional groups of organisms. The ecosystem model was used to estimate the environmental transfer of 13 elements (Al, Ca, Cd, Cl, Cs, I, Ni, Nb, Pb, Se, Sr, Th, U) to various aquatic organisms, using element-specific distribution coefficients for suspended particles (Kd PM) and upper sediment (Kd sed), and subsequent transfer in the foodweb. The modelled CRs for different organism groups were compared with measured CRs from the lake and literature data, and showed good agreement for many elements and organisms, particularly for lower trophic levels. The model is, therefore, proposed as an alternative to measured CR, though it is suggested to further explore active uptake, assimilation and elimination processes to get better correspondence for some of the elements. The benthic organisms (i.e. bacteria, microphytobenthos and macroalgae) were identified as more important than pelagic organisms for transfer of elements to top predators. The element transfer model revealed that most of the radionuclides were channelled through the microbial loop, despite the fact that macroalgae dominated the carbon fluxes in this lake. Thus, element-specific adsorption of elements to the surface of aquatic species, that may be food sources for organisms at higher trophic levels, needs to be considered in combination with generic processes described by carbon fluxes. - Highlights: • A process-based element transport model for a shallow lake was developed. • CRs for 13 elements in 11 functional groups of organisms were estimated. • The model estimated which organisms in the food web accumulate more than others. • The model identified the compartments and processes important in element cycling. • Benthic bacteria were identified as important for element transport.