Browsing by Author "Yankovich, TL"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Biota dose modelling: Little Forest Burial Ground scenario
    (Australian Nuclear Science and Technology Organisation, 2012-10-16) Johansen, MP; Barnett, CL; Beresford, NA; Brown, JE; Černe, M; Howard, BJ; Kamboj, S; Keum, DK; Payne, TE; Smodiš, B; Twining, JR; Vandehnove, H; Vives i Batlle, J; Wood, MD; Yankovich, TL; Yu, C
    Radiation doses to terrestrial wildlife were examined in a model inter-comparison study on a diverse range of terrestrial plants and animals at the Little Forest Burial Ground, NSW, Australia. This inter-comparison was one in a series conducted under the IAEA Environmental Modelling for Radiation Safety Programme (EMRAS), which indicated general agreement among available biota dose models in the use of dose conversion parameters for standard organisms and geometries. However, notable variation in dose estimates emerged when the models were applied to a terrestrial deposition scenario (Chernobyl exclusion zone, Ukraine); a freshwater aquatic scenario (Perch Lake, Canada; a low-level burial ground scenario (Little Forest Burial Ground, Australia;), as well as additional aquatic (Beaverlodge, Canada) and wetlands (various locations) scenarios currently underway. Given the range in outcomes from the various modelling approaches of the previous EMRAS studies, the Little Forest Burial Ground scenario focused on quantifying the factors causing variation. The dominant variable factor (up to orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides. Additional variation was associated with: exposure configurations (two orders of magnitude when considering trees growing on the waste trenches); inclusion/exclusion of progeny in Th and U isotopes (typically less than one order of magnitude); and radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). At Little Forest, results suggest radionuclide uptake is occurring in wildlife, but at low levels as most organisms only access the relatively clean surface soils above the buried wastes. Doses to acacia tree were elevated, however, due to its deeper roots having direct access to the buried wastes, with predictions of 95th percentile doses above the screening levels indicating further study is warranted. Our study confirms and adds to the outcomes of previous EMRAS studies in quantifying the sources of variation in biota dose modelling, and highlights soil to-organism transfer as a key source of uncertainty. It prompts continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife.
  • No Thumbnail Available
    Item
    Ensuring robust radiological risk assessment for wildlife: insights from the International Atomic Energy Agency EMRAS and MODARIA programmes
    (Published on behalf of the Society for Radiological Protection by IOP Publishing Limited, 2022-05-03) Beresford, NA; Beaugelin-Seiller, K; Barnett, CL; Brown, JE; Caffrey, EA; Johansen, MP; Melintescu, A; Ruedig, E; Vandenhove, H; Vives i Batlle, J; Wood, MD; Yankovich, TL; Copplestone, D
    In response to changing international recommendations and national requirements, a number of assessment approaches, and associated tools and models, have been developed over the last circa 20 years to assess radiological risk to wildlife. In this paper, we summarise international intercomparison exercises and scenario applications of available radiological assessment models for wildlife to aid future model users and those such as regulators who interpret assessments. Through our studies, we have assessed the fitness for purpose of various models and tools, identified the major sources of uncertainty and made recommendations on how the models and tools can best be applied to suit the purposes of an assessment. We conclude that the commonly used tiered or graded assessment tools are generally fit for purpose for conducting screening-level assessments of radiological impacts to wildlife. Radiological protection of the environment (or wildlife) is still a relatively new development within the overall system of radiation protection and environmental assessment approaches are continuing to develop. Given that some new/developing approaches differ considerably from the more established models/tools and there is an increasing international interest in developing approaches that support the effective regulation of multiple stressors (including radiation), we recommend the continuation of coordinated international programmes for model development, intercomparison and scenario testing. © 2022 Society for Radiological Protection.
  • Thumbnail Image
    Item
    The environmental behaviour of uranium
    (International Atomic Energy Agency, 2023) Carvalho, FP; Fesenko, S; Harbottle, AR; Lavrova, T; Mitchell, NG; Payne, TE; Rigol, A; Thorne, MC; Ulanowski, A; Vidal, M; Voitsekhovych, O; West, JM; Yankovich, TL
    This publication is one of the series of IAEA publications on the environmental behaviour of naturally occurring radionuclides It outlines uranium behaviour in different environments, as well as its transfer to, and metabolism in, humans The publication also provides concepts, models and data required for the assessment of the impacts of uranium on non-human biota Assessing the environmental and health effects of uranium poses specific challenges because of the combination of different types of hazard and potential exposures Therefore, both the radiotoxicity and chemical toxicity of uranium are considered in this publication.
  • No Thumbnail Available
    Item
    The IAEA handbook on radionuclide transfer to wildlife
    (Elsevier B.V., 2013-07-01) Howard, BJ; Beresford, NA; Copplestone, D; Telleria, D; Proehl, G; Fesenko, S; Jeffree, RA; Yankovich, TL; Brown, JE; Higley, K; Johansen, MP; Mulye, H; Vandenhove, H; Gashchakk, S; Wood, MD; Takatam, H; Andersson, P; Dale, P; Ryan, J; Bollhöfer, A; Doering, C; Barnett, CL; Wells, C
    An IAEA handbook presenting transfer parameter values for wildlife has recently been produced. Concentration ratios (CRwo-media) between the whole organism (fresh weight) and either soil (dry weight) or water were collated for a range of wildlife groups (classified taxonomically and by feeding strategy) in terrestrial, freshwater, marine and brackish generic ecosystems. The data have been compiled in an on line database, which will continue to be updated in the future providing the basis for subsequent revision of the Wildlife TRS values. An overview of the compilation and analysis, and discussion of the extent and limitations of the data is presented. Example comparisons of the CRwo-media values are given for polonium across all wildlife groups and ecosystems and for molluscs for all radionuclides. The CRwo-media values have also been compared with those currently used in the ERICA Tool which represented the most complete published database for wildlife transfer values prior to this work. The use of CRwo-media values is a pragmatic approach to predicting radionuclide activity concentrations in wildlife and is similar to that used for screening assessments for the human food chain. The CRwo-media values are most suitable for a screening application where there are several conservative assumptions built into the models which will, to varying extents, compensate for the variable data quality and quantity, and associated uncertainty. © 2012, Elsevier Ltd.
  • No Thumbnail Available
    Item
    Whole-body to tissue concentration ratios for use in biota dose assessments for animals
    (Springer, 2010-11) Yankovich, TL; Beresford, NA; Wood, MD; Aono, T; Andersson, P; Barnett, CL; Bennett, P; Brown, JE; Fesenko, S; Fesenko, J; Hosseini, A; Howard, BJ; Johansen, MP; Phaneuf, MM; Tagami, K; Takata, H; Twining, JR; Uchida, S
    Environmental monitoring programs often measure contaminant concentrations in animal tissues consumed by humans (e.g., muscle). By comparison, demonstration of the protection of biota from the potential effects of radionuclides involves a comparison of whole-body doses to radiological dose benchmarks. Consequently, methods for deriving whole-body concentration ratios based on tissue-specific data are required to make best use of the available information. This paper provides a series of look-up tables with whole-body:tissue-specific concentration ratios for non-human biota. Focus was placed on relatively broad animal categories (including molluscs, crustaceans, freshwater fishes, marine fishes, amphibians, reptiles, birds and mammals) and commonly measured tissues (specifically, bone, muscle, liver and kidney). Depending upon organism, whole-body to tissue concentration ratios were derived for between 12 and 47 elements. The whole-body to tissue concentration ratios can be used to estimate whole-body concentrations from tissue-specific measurements. However, we recommend that any given whole-body to tissue concentration ratio should not be used if the value falls between 0.75 and 1.5. Instead, a value of one should be assumed. © 2010, Springer.