[en] Butterflies of the Lymanopoda genus are typical of the high Andean ecosystem and they are characterized by having species of Chusquea genus as host plants. This research aims to present the habitat description of four species of Lymanopoda inhabiting in paramo areas of the Colombian Andes. The habitat description was based on searching butterflies in three localities; two at the Cordillera Oriental and another one at the Cordillera Occidental. After, we explored the floristic composition of inhabiting areas by the Lymanopoda species and we registered data to calculate vegetation coverage and relative frequency of tree, shrub and herb layers. Such data made it possible to identify patterns in botanical physiognomy, structure and diversity of the vegetal coverages among the butterflies that were found. Our outcomes show that although the floristic composition between the four localities is different, the abundance distribution of species is related to limited dominance and high equitability. With regard to vegetation structure we found that shrub layer and Chusquea spp. Coverage is similar at an edge of the patches. Based on the results, we conclude that presence of Chusquea is essential to the assessed butterflies but also, they only reside inside diverse vegetation coverages (i.e. with limited dominance and high equitability) whit a botanical structure that includes tree, shrub and herb layers.

[en] A fully 3-D Lagrangian stochastic particle trajectory model is presented and applied to the meso-scale atmospheric dispersion and ground concentration calculations. The use of Gaussian plume model (GPM) with Pasquill-Gifford σ's for downwind distances exceeding 10 km is critically viewed. Further, the effect of variation in release height on the ground concentration and dispersion parameters (σ_y,σ_z) is studied for continuous releases. A continuous release of a non-buoyant gas in a neutral stratified atmosphere is simulated for various stack heights. The turbulent atmospheric parameters like vertical profiles of the fluctuating wind component and the eddy lifetimes for the horizontal and vertical directions, etc. were calculated using a semi-empirical mathematical model and compared with a E-ε model. The numerically calculated horizontal and vertical dispersion coefficients (σ_y,σ_z) are compared with the Pasquill-Gifford empirical σ's and with the Pasquill-modified σ_y. The ground concentration values as a function of downwind distance, have been compared with the Green Glow data and with a GPM for various release heights. The comparison of the results demonstrate a need of using a 3-D model over the simple GPM for meso-scale atmospheric dispersion applications. The GPM overpredicts the ground concentration because it cannot take into account the vertical wind shear, which is observed in the atmosphere under all stability conditions. A weak dependence on the release height in the numerically calculated dispersion coefficients σ's, is also observed

[en] The Chernobyl accident has clearly shown the long-term effects of a radioactive contamination of forest ecosystems. This report is based on a literature review of models which describe the migration of radionuclides, radioactive caesium in particular, in forest ecosystems. The report describes the particularities of the forest ecosystem, the time dynamics of the contamination, the transfer processes and factors influencing caesium migration. This provides a basis for a discussion of different approaches for modelling caesium migration in the forest. It is concluded that the studied dynamic models include the most relevant transfer processes both for the acute and the long-term phase after a radioactive deposition. However, most models are site specific and do not consider some of the factors responsible for the differences in radionuclide behaviour and distribution in different types of forests. Although model improvements are constrained by the availability of experimental data and by the lack of knowledge of the migration mechanisms some possible improvements are discussed. This report is part of the LANDSCAPE project. -An integrated approach to radionuclide flow in the semi-natural ecosystems underlying exposure pathways to man

[en] A core element of risk is uncertainty represented by plural outcomes and their likelihood. No risk exists if the future outcome is uniquely known and hence guaranteed. The probability that we will die some day is equal to 1, so there would be no fatal risk if sufficiently long time frame is assumed. Equally, rain risk does not exist if there was 100% assurance of rain tomorrow, although there would be other risks induced by the rain. In a formal sense, any risk exists if, and only if, more than one outcome is expected at a future time interval. In any practical risk assessment we have to deal with uncertainties associated with the possible outcomes. One way of dealing with the uncertainties is to be conservative in the assessments. For example, we may compare the maximal exposure to a radionuclide with a conservatively chosen reference value. In this case, if the exposure is below the reference value then it is possible to assure that the risk is low. Since single values are usually compared; this approach is commonly called 'deterministic'. Its main advantage lies in the simplicity and in that it requires minimum information. However, problems arise when the reference values are actually exceeded or might be exceeded, as in the case of potential exposures, and when the costs for realizing the reference values are high. In those cases, the lack of knowledge on the degree of conservatism involved impairs a rational weighing of the risks against other interests. In this presentation we will outline an approach for dealing with uncertainties that in our opinion is more consistent. We will call it a 'fully probabilistic risk assessment'. The essence of this approach consists in measuring the risk in terms of probabilities, where the later are obtained from comparison of two probabilistic distributions, one reflecting the uncertainties in the outcomes and one reflecting the uncertainties in the reference value (standard) used for defining adverse outcomes. Our first aim is to delineate the approach, in comparison with the deterministic approach, to define the entities involved in the assessment and their relationship. The second aim is to identify possible strategies for deriving and combining the probability distributions. In the explanation we will use a terminology that is related to the exposure to radionuclides in the environment. (author)

[en] The present study is part of an on-going research project which focuses on the transfer of ¹³⁷Cs to roe deer and moose living in contaminated forests. The specific aim was to describe and explain the seasonal, yearly and long- term variations of radiocaesium levels in roe deer and moose. A particularity of the study was that field observations were combined with the development of mathematical models

[en] Positron Emission Tomography (PET) is a non-invasive diagnostic imaging technique modality. It represents the forefront of medical images and was developed as a quantitative technique for imaging biochemical and physiological processes in the human body. PET is unique because it produces images of the body's basic biochemistry or function. Traditional diagnostic techniques such as x-rays, CT scans or MRI, produce images of the body's anatomy or structure. The premise with these techniques is that the change in anatomy or structure that occurs with disease can be seen. However, biochemical processes are also altered with disease and may occur before there is a change gross anatomy. PET is an imaging technique that is used to visualize some of these processes. The development of PET as we know it today began in 1974 with the development of a single ring detector system by Phelps et al. Today, over 350 PET scanners are in use in the world, mainly in the USA (over 140), Europe (particularly in the Anglo-Saxon countries and France) and Japan. Many of these facilities also have their own cyclotron to produce the positron emitters. In the Southern hemisphere, only Australia, Argentina. and recently Mexico, have a very small number of PET facilities. (Author)

[en] Currently, there is no established methodology to estimate radiation doses to non-human biota. Therefore, in this study, various dose models were used to estimate radiation doses to moor frogs (Rana arvalis) in a wetland ecosystem contaminated with ¹³⁷Cs. External dose estimations were based on activity concentrations of ¹³⁷Cs in soil and water, considering changes in habitat over a life-cycle. Internal doses were calculated from the activity concentrations of ¹³⁷Cs measured in moor frogs. Depending on the dose model used, the results varied substantially. External dose rates ranged from 21 to 160 mGy/y, and internal dose rates varied between 1 and 14 mGy/y. Maximum total dose rates to frogs were below the expected safe level for terrestrial populations, but close to the suggested critical dose rate for amphibians. The results show that realistic assumptions in dose models are particularly important at high levels of contamination

[en] There is an acknowledged lack of available data to derive parameters describing the transfer of many radionuclides from soil to wild species. Furthermore, many approaches to estimating the internal exposure of biota assume equilibrium transfer from soil to biota. However, as environmental impact assessments may need to be conducted for many scenarios (e.g. chronic or acute releases to air and ground waters) assumptions of equilibrium soil to biota transfer many be neither sufficient nor conservative. Much effort has previously been devoted to derive semi-mechanistic models to enable the transfer of radionuclides through human food chains to be predicted dynamically. A logical first step to addressing the data gaps in our ability to predict internal activity concentrations of biota is to consider adapting these models for wild species. Here we describe the development of a semi-mechanistic model to estimate activity concentrations in wild mammals by adaptation of existing human food chain models. Interception, weathering, plant uptake and soil migration parameters are derived from previously published models or collations such as IAEA Technical Report Series No. 364. Allometric relationships dependent on body mass are used to estimate wild animal parameters including, for most radionuclides, biological half-life. Comparison of predictions with observed data allows limited comment on the validity of model predictions. For instance, predicted Cs values are within observed ranges, and an increase in Cs activity concentrations from prey-carnivore as observed by many authors is predicted. Predicted values for ⁹⁰Sr, ²²⁶Ra and U also appear reasonable whilst those for the actinide elements are low compared with the limited available data. To date a simple source-grass-herbivore-carnivore food chain has been considered; the potential for further development of the model is discussed. (author)

[en] Internal and external radiation doses to frogs living in a wetland ecosystem contaminated with ¹³⁷Cs were estimated. The external doses were calculated from measured concentrations of ¹³⁷Cs in soil and in water taking into account changes in the habitat during the frogs' life cycle. The internal dose was estimated from measured concentrations of ¹³⁷Cs in living frogs (Rana arvalis) using a whole-body counter. The average inventory of ¹³⁷Cs in the soil was approximately 1000 kBq/m² of which 86-99 % was found in the top 12 cm. The concentrations of ¹³⁷Cs in frogs varied between 560 and 3450 Bq/kg ww. The estimated external dose rate was between 21 and 160 mGy/y, while the internal dose of beta and gamma was only between 1 and 6.2 mGy/y. The estimated total dose rate to frogs from ¹³⁷Cs was below the expected safe level for terrestrial populations but close to the critical dose rate for amphibians suggested in the literature. Therefore, the radiation risk to frogs from radiocaesium in the study area may be one more stressor for an endangered group of animals in this ecosystem. (author)

[en] This report describes methods and data for calculation of doses to man to be used in safety assessments of repositories for nuclear fuel. The methods are based on the latest recommendations from the ICRP, the EU and the national radiation protection authorities. Equations are given for calculation of doses from ingestion of contaminated water and food, inhalation of contaminated air and external exposure from radionuclides in the ground. With the exception of the exposure from food ingestion, the equations are the same used in previous safety assessments. A general equation is suggested for estimation of the exposure from food ingestion, in which the annual demand of carbon is used instead of the annual ingestion of different foodstuffs, which was earlier applied. The report contains tables with recommended values for physiological characteristics such as water intake, food intake and inhalation rates, based on information summarised in an Appendix. Furthermore, tables are given with recommended age dependent dose conversion factors for ingestion and inhalation for a number of nuclides of interest for safety assessments. The most recently published dose conversion factors for external exposure from contaminated ground are also given. An overview of the implementation of the methodology in Pandora, which is the tool that Posiva and SKB currently use for biosphere modelling, is also provided. The work presented in the report is a result from a joint project commissioned by Svensk Kaernbraenslehantering AB (SKB) and Posiva. The report will be printed also as a SKB report R-06-68. (orig.)