Browsing by Author "Hirth, GA"

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    Developing international radiological risk assessment tools for Australian arid environments
    (South Pacific Environmental Radioactivity Association, 2018-11-06) Popelka-Filcoff, RS; Pring, A; Pandelus, SB; Johns, SM; Tucker, W; Rossouw, D; Lenehan, CE; Hondros, J; Hirth, GA; Carpenter, JG; Johansen, MP; Payne, TE; Roberts, M; Levingstone, K; Tuft, K; Duff, T
    Recent international and Australian regulatory guidance llCRP 108 and ARRANSA Env. Prot. Guide, 2015) has increased the need for effective tools to assess radiological impacts in the environment. The existing internationally accepted methods and models are generally based on data collected in the northern hemisphere and there is a recognised lack of southern hemisphere data, particularly from Australia. When applying the models and methods in Australia, acknowledgement of this lack of data is required which tends to undermine public and regulatory confidence in the assessment. Development of an Australian-specific data set is essential to a better understanding and more credible environmental impact assessment process. In addition, decision-making by operators and regulatory authorities will be based on more relevant local information This presentation describes a collaborative project between university, government and industry researchers and a national industry funding body, aimed at developing a more complete understanding of radiological uptake of native flora and fauna in arid Australian environments. The presentation will cover the framework and sampling and analysis approaches from arid environments, and how these fit into international practice. lnitial data and concentration ratios from analysis of Dodonaea viscosa and Acacia ligulata, rabbits and feral cats and corresponding soil will be presented. Analytical methods include high-resolution gamma spectroscopy with low limits of detection, alpha spectroscopy, elemental analysis by inductively coupled plasma mass spectrometry, scanning electron microscopy. ant"; 3."; 5 Novel approaches to data collection and analysis protocols are used, which form the basis of the databases use: :. i"e internationally accepted models and comparison to extant studies. The project lays the infrastructure towards an effective Australian intenface with existing tools (e.g. ERICA) and assessment for extended long-term studies for industry and regulators. The results of this project build a foundation for environmental radionuclide assessment for Australia's specific climate and species, and build a framework for a comprehensive Australian context and understanding of radionuciides and their concentration ratios as well as towards screening levels which may vary depending on location and species. This project has an industry-wide impact in the generation of robust data sets towards modelling in arid environments.
  • No Thumbnail Available
    Item
    Protection of the environment
    (SAGE, 2020-08-28) Copplestone, D; Hirth, GA; Cresswell, T; Johansen, MP
    The International Commission on Radiological Protection’s (ICRP) system to protect the living components of the environment is designed to provide a broad and practical framework across different exposure situations. The framework recognises the need to be able to demonstrate an adequate level of protection in relation to planned exposure situations, whilst also providing an ability to manage existing and emergency situations in an appropriate way. In all three exposure situations, the release of radionuclides into the natural environment leads to exposures of non-human biota (wildlife), as well as having the potential for exposures of the public. How the key principles of the ICRP system of radiological protection apply in each of these exposure situations will be discussed. Using examples, we will demonstrate how the overall approach provides a mechanism for industry to assess and demonstrate compliance with the environmental protection objectives of relevant (national) legislation, and to meet stakeholder expectations that radiological protection of the environment is taken into consideration in accordance with international best practice. However, several challenges remain, and these will be discussed in the context of the need for additional guidance on the protection of the environment. Copyright © 2020 by International Commission of Radiological Protection, published by SAGE.
  • Thumbnail Image
    Item
    Recent development of wildlife transfer databases
    (International Union of Radioecology, 2014) Beresford, NA; Copplestone, D; Hosseini, A; Brown, JE; Johansen, MP; Hirth, GA; Sheppard, S; Dagher, E; Yankovich, T; Uchida, S; Napier, J; Outola, I; Wells, C; Barnett, CL; Wood, MD; Howard, BJ
    The transfer of radionuclides to wildlife in the environmental radiological assessment models developed over the last two decades is most often described by the whole organism concentration ratio (CRwo-media). This parameter relates whole organism activity concentrations to those in environmental media (typically soil for terrestrial ecosystems and water for aquatic ecosystems). When first released in 2007, the ERICA Tool contained the most comprehensive and well documented CRwo-media database available for wildlife. It was subsequently used in the US DOE RESRAD-BIOTA model and formed the initial basis for the international wildlife transfer database (WTD; www.wildlifetransferdatabase.org/?) developed to support IAEA and ICRP activities. Subsequently, many additional data were input to the WTD, including the outputs of a review of Russian language literature and data from Canadian monitoring programmes associated with nuclear power plants, U-mining and related industries. Summarised data from the WTD in 2011 were used to provide CRwo values in ICRP 114 and the IAEA's handbook on wildlife transfer parameters (http://www-ns.iaea.org/projects/emras/emras2/working-groups/working-group-five.asp?s=8&l=63). This paper provides an update on the development of the WTD subsequent to 2011 and its application to derive revised default CRwo-media parameter values of the ERICA Tool. Since 2011, some circa 17,000 additional CRwo-media values have been added to the WTD. The new inputs include original data for: representative species of the ICRPs Representative Animals and Plants (RAPs) from a UK forest; monitoring data from Japanese estuaries and Finland; Canadian wildlife; plutonium uptake data from US weapons testing programme sites; wild plants and invertebrates from north western USA; refereed literature published after 2011. Additionally, data already in the WTD from Australia were reviewed with reference to original source reports not previously considered and amended where required. The revised WTD was quality checked by considering the degree of variation in the data for each organism-element combination and the change between the WTD versions. This identified a number of errors (e.g. double entry of data, unit conversion errors and entries based on a dry matter rather than the required fresh weight basis) all of which have now been rectified. Statistical analyses of the WTD have demonstrated that there is currently no justification to subdivide CRwo-media from e.g. mammal to mammal herbivore and mammal carnivore etc.. In revising the ERICA Tool, a more generic categorisation of organisms has subsequently been used. Even with the increase in available data, there are still many radionuclide-organism combinations for which data are lacking. To provide default values where there are no data, a set of rules have been derived including the use of Bayesian statistics. (authors)
  • No Thumbnail Available
    Item
    Recent developments in the modelling of radionuclide uptake, radiation dose and effects in wildlife
    (South Pacific Environmental Radioactivity Association, 2014-09) Johansen, MP; Beresford, NA; Howard, BJ; Hinton, TG; Bollhöfer, A; Doering, C; Hirth, GA; Grzechnik, M; Ruedig, E; Payne, TE; Twining, JR
    Of the ~600 scientific publications on the Fukushima event, more than 80% relate to themes of transport of radionuclides in environmental media, transfer to wildlife and foodstuffs, and dose to environmental receptors. This focus reflects a continued need for development and harmonisation of radiological modelling approaches such as has been underway through recent IAEA and ICRP initiatives (e.g. EMRAS I and II, MODARIA). Key developments in improving the understanding of uptake of radionuclides in wildlife include establishing the Wildlife Transfer Parameter Database and related IAEA handbook on transfer to wildlife. These sources provide access to a comprehensive collection of transfer parameters, including input from Australian sources (www.wildlifetransferdatabase.org). Key improvements were highlighted in a recent Journal of Environmental Radioactivity special issue (Vol. 121). Dose modelling for wildlife continues to be challenged by the high diversity of biotic types (plankton to whales) and the breadth of exposure scenarios in diverse ecosystems. Modelling codes (e.g. ERICA Tool, RESRAD-Biota) are undergoing updates of their transfer parameters, improvement of capabilities such as probabilistic analysis (e.g. Monte Carlo), and harmonization of approaches through IAEA model testing exercises (e.g., Little Forest Burial Ground biota dose modelling assessment). A recent development has been the use of voxel dosimetry approaches which build on the standard simplified ellipsoid approach by modelling the absorbed doses in individual organs. Recent improvements in defining dose effects to environmental receptors have focused on updating the FREDERICA Radiation Effects Database. The more comprehensive data have allowed for the updating/development of new Species Sensitivity Distributions that better support the benchmark values for potential dose effects, and for improving estimation of population effects (rather than individuals) upon which the environmental protection strategies are based.
  • Thumbnail Image
    Item
    Whole-organism concentration ratios in wildlife inhabiting Australian uranium mining environments
    (International Union of Radioecology, 2014-09-07) Hirth, GA; Carpenter, JG; Bollhöfer, A; Johansen, MP; Beresford, NA
    Environmental impact assessments conducted for Australian mine sites involving naturally occurring radioactive material require an assessment of radiation doses to wildlife. Whole-organism concentration ratios (CRwo) are pivotal in these assessments and previous reviews have identified a need for a more complete and consolidated database of Australian-specific CRwo that could be used. Concern had also been expressed by some stakeholders in Australia about the suitability of the default CRwo values provided in standard biota dose models (e.g., ERICA Tool, RESRAD-BIOTA, ICRP framework) for Australian wildlife and environmental conditions. In order to address these concerns and support the implementation of best-practice standards in environmental radiological assessment, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), with support from the Department of Resources, Energy and Tourism (RET), undertook an evaluation of existing data relating to wildlife inhabiting Australian uranium mining environments. CRwo values were calculated using data from a range of original sources. These included scientific journal publications, technical reports from Australian government organisations, site-specific data from mining operators and data from baseline environmental surveys undertaken during the 1970's and 1980's. The Australian data previously included in the international Wildlife Transfer Database (WTD, www.wildlifetransferdatabase.org) were also reviewed and updated. This paper discusses the data analysis process and associated uncertainties. CRwo values are reported for uranium, thorium, radium-226, lead-210 and polonium-210 for a range of endemic and introduced wildlife, with a focus on plants and animals from both terrestrial and freshwater environments where uranium mining has been proposed or undertaken. This has resulted in the calculation of more than 500 CRwo values for inclusion in the database. Australian-specific CRwo values will be compared to general values reported in the WTD including examples of specific wildlife groups or unique environmental conditions that are outside the range of the CRwo values in the WTD. Recommendations regarding biota types and environmental conditions for which data are most lacking will also be discussed. ©2008 IUR - International Union of Radioecology
  • Thumbnail Image
    Item
    Whole-organism concentration ratios in wildlife inhabiting Australian uranium mining environments
    (Elsevier B. V., 2017-11) Hirth, GA; Johansen, MP; Carpenter, JG; Bollhöfer, A; Beresford, NA
    Wildlife concentration ratios for 226Ra, 210Pb, 210Po and isotopes of Th and U from soil, water, and sediments were evaluated for a range of Australian uranium mining environments. Whole-organism concentration ratios (CRwo-media) were developed for 271 radionuclide-organism pairs within the terrestrial and freshwater wildlife groups. Australian wildlife often has distinct physiological attributes, such as the lower metabolic rates of macropod marsupials as compared with placental mammals. In addition, the Australian CRswo-media originate from tropical and semi-arid climates, rather than from the temperate-dominated climates of Europe and North America from which most (>90%) of internationally available CRwo-media values originate. When compared, the Australian and non-Australian CRs are significantly different for some wildlife categories (e.g. grasses, mammals) but not others (e.g. shrubs). Where differences exist, the Australian values were higher, suggesting that site-, or region-specific CRswo-media should be used in detailed Australian assessments. However, in screening studies, use of the international mean values in the Wildlife Transfer Database (WTD) appears to be appropriate, as long as the values used encompass the Australian 95th percentile values. Gaps in the Australian datasets include a lack of marine parameters, and no CR data are available for freshwater phytoplankton, zooplankton, insects, insect larvae or amphibians; for terrestrial environments, there are no data for amphibians, annelids, ferns, fungi or lichens & bryophytes. The new Australian specific parameters will aide in evaluating remediation plans and ongoing operations at mining and waste sites within Australia. They have also substantially bolstered the body of U- and Th-series CRwo-media data for use internationally. ©2017 The Authors.