A review of existing Australian radionuclide activity concentration data in non-human biota inhabiting uranium mining environments

by

Gillian Hirth

Technical Report 167
ISSN 0157-1400
May 2014 / 619 Lower Plenty Road
Yallambie VIC 3085
Telephone: +61 3 6433 2211
Facsimile: +61 3 9432 1835

Table of Contents

Acknowledgements......

Executive Summary......

1.Introduction......

1.1Background......

1.2Purpose and Scope......

1.3Structure......

2.Concepts and Approach......

2.1Terminologies......

2.2International Initiatives......

2.3Australian Uranium Mining Environments......

3.Data Collection, Review and Evaluation......

3.1Data Collection......

3.2Data Review and Evaluation......

3.3Data Manipulation......

3.4Issues Arising......

4.Conclusions......

4.1Recommendations......

5.References......

Appendix 1Reports and Publications Reviewed......

Appendix 2Conversion Factors......

Appendix 3Australian Whole-organism CR – Current......

Appendix 4Summary of Data Identified During Project......

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Acknowledgements

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) wishes to acknowledge the Department of Industry (DI) for their financial support of this project.The author would like to acknowledge the valuable support offered by the members of the Steering Committee:Michael Sheldrick and Emma Dasey (DI); Rick Tinker and Stephen Solomon (ARPANSA); Andreas Bollhöfer (Environmental Research Institute of the Supervising Scientist) and industry representatives MrFrankHarris, Ms KatrinaJames and Ms Kathryn Taylor.

The author would also like to thankChes Mason, Barbara Radcliffe and Jim Hondros (BHP Billiton) for the time spent reviewing archives to provide data for this project; andMat Johansen (ANSTO), John Twining (AusRad Eco) and Nick Beresford (Centre for Ecology & Hydrology, UK) for their time, technical input, advice and cooperation in sharing their expertise and data, your guidance and discussion was greatly appreciated. Finally, thanks to Marcus Grzechnik and Julia Carpenter (ARPANSA) for their support, quality assurance checks and reviewof this report.

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Executive Summary

It is now generally accepted that there is a need to demonstrate, rather than assume, that non-human biota(e.g. animals and plants) living in natural habitats are protected against ionising radiation risks from radionuclides released to the environment by human activities (ARPANSA, 2014).Uranium mining and milling activitieshave been conducted in Australia since the 1950s and have the potential to release radionuclides to the environment. Consequently this may result in exposures of non-human biota in natural habitats to ionising radiation at levels above the natural background.

Following a previous report by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) (Doering, 2010), theDepartment of Industry (DI) and ARPANSAagreed that in order to support the implementation of international best practice standards in environmental radiological assessment in Australia, an evaluation of existing data relating to non-human biota inhabiting Australian uranium mining environments should be undertaken. In August 2011 DI (then Department of Resources, Energy and Tourism) and ARPANSA signed a Memorandum of Understanding to undertake the project Concentration ratios in non-human biota inhabiting Australian uranium mining and milling environments. This project was toidentify any shortcomings, including biota types and environmental conditions for which data is most lacking, taking into account the location of current and prospective uranium mines in Australia.Data were to be evaluated for their suitability for use in calculating whole-organism concentration ratios which are used to estimate the transfer of radionuclides from the environment to non-human biota and are an important data requirement when conducting environmental radiological assessments.

This report provides a summary and evaluation of existing radionuclide concentration data in non-human biota common to Australian uranium mining environments that have been collected by a range of organisations over the past 40 years.Where possible, whole-organism concentration ratios for terrestrial and freshwater non-human biota common to Australian uranium mining and milling and uranium deposit regions have been calculated.Thishas resulted in an increase in the number of wildlife groups for which whole-organism concentration ratios can be reported for Australian uranium mining environments. For terrestrial habitats (predominantly arid/desert mining areas) concentration ratios for two wildlife groups (mammal and reptile) have currently been included in the international Wildlife Transfer Parameters database, additional concentration ratios have now been determined for birds, grasses and herbs, shrubs and trees.For freshwater habitats (predominantly tropical mining areas)additional concentration ratios have been identified for most of the wildlife groups currently included in the international database, and one additional wildlife group (algae).

In relation to data gaps there are a number of topics that should be considered and discussed within the environmental radiation protection/radioecology community and could form the basis of further work.These include:

  • Developing Australian specific ash to fresh and dry to fresh weight ratios for terrestrial plants, particularly for those existing in arid/desert areas and for trees including Eucalyptus and Melaleuca species.
  • Investigating the distribution coefficient (Kd) values for Australian aquatic environments (i.e. the relationship between sediment values and activity concentration in filtered water) and whether these should be applied to estimating media concentrations in the absence of data.
  • Establishing the approach to be taken for the inclusion/exclusion of values reported as less than the limit of detection in datasets when determining concentration ratios for Australian non-human biota.

Whilst less relevant to the uranium mining industry, the development of thorium tissue to whole-organism conversion factors may be relevant to other industries (i.e. mineral sands) and could be investigated by examining the Australian datasets in more detail.

Recommendations

From the analysis and conclusions of this report ARPANSA recommends that:

  1. The terminology to be used in Australia in the future, and how data on domesticated species is incorporated, should be considered as national guidance is developed for radiation protection of the environment in Australia. This guidance should also include recommended sampling and analysis regimes to ensure consistency across the industry sector.
  2. The cooperative relationship with industry undertaken during this project isfurther developed to establish a non-human biota dataset relevant to uranium environments that includes any additional industry data.This is particularly relevant for those extensive datasets that have not yet been paired with media data.
  3. The data that have been collated during this project should be published.Publication of this data will benefit the Australian uranium mining industry by consolidating the existing datasets, enabling a comparison to the international values, and assisting in supporting more robust radiological assessments, particular in the screening phase of assessments for long term exposure scenarios for equilibrium situations.
  4. Discrepancies in the current Australian dataset incorporated into the international Wildlife Transfer Parameters Database should be reconciled; the approach to be taken with Australian data when including/excluding limit of detection values should be discussed and agreed within the radioecology/radiation protection research community; additional information that may be available from the Environmental Research Institute of the Supervising Scientist (ERISS) should be incorporated.
  5. This information should be incorporated into the international Wildlife Transfer Parameter Database and a comparison of Australian concentration ratios to the International Atomic Energy Agency (IAEA) and the International Commission on Radiation Protection (ICRP) summary values should be undertaken.This process should be donein a coordinated mannerwith industry, research bodies and relevant Commonwealthagencies.

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1.Introduction

1.1Background

The International Commission on Radiological Protection (ICRP) – the primary international body issuing both generic and specific recommendations on protection against ionising radiation –revised its fundamental recommendations in 2007 (ICRP, 2007) to include a framework for assessment and protection of non-human species.The framework (ICRP, 2009) uses a generically defined group of organisms (usually at the taxonomic level of Family) referred to as Reference Animals and Plants (RAPs) to establish datasets that allow assessors to relate the transfer of radionuclides from the environment to organisms, radiation exposure to dose, and dose to effect.In addition to the ICRP, the International Atomic Energy Agency (IAEA) in their Fundamental Safety Principles (IAEA, 2006) and International Basic Safety Standards (IAEA, 2011) now also include the need to demonstrate that the environment is protected from the harmful effects of ionising radiation.

The ICRP RAPs serve as a reference for further assessments, and can be used as default representative organisms in a particular assessment context.The RAP dataset can also be used to derive, as best as possible, appropriate datasets that better suit the organisms (the representative organisms) in the actual environment being assessed.For the purpose of this report, the term reference organisms is being used as being equal to representative organisms, using available data sources including those that have been generated by the ICRP for the RAPs.The science underpinning the RAP approach has been developed over the last ten years through several multi-national research efforts which have been focussed on the development of modelling approaches specifically to assess ionising radiation exposures to biota living in its natural habitat (e.g. Beresford et al., 2008a; Howard and Larsson, 2008;IAEA, 2010).A number of countries are now using the approach in a regulatory context for nuclear and other sites releasing radionuclides to the environment to show compliance with environmental protection aims as laid out in relevant legislation (Howard et al.,2012).

Uranium mining and milling actions have been conducted in Australia since the 1950s and have the potential to release radionuclides to the environment.This may result in exposures of non-human species (i.e. animals and plants) in natural habitats to ionising radiation.This in turn may cause deleterious effects in individuals and populations of species.The Environment Protection and Biodiversity Conservation (EPBC) Act 1999 – Australia’s national environmental protection legislation – explicitly recognises mining or milling uranium ore as a nuclear action.Where decided by the Minister, the Act requires the proponent of a uranium mining or milling action to undertake an environmental assessment and address the relevant impacts of the action through the environmental impact statement process.It is implicit that the environmental assessment should include an assessment of the potential radiological impacts of the mining or milling action on the surrounding environment, including non-human biota.It is also Australian Government policy that uranium mining and milling should be basedon international best practice standards and on extensive continuing research on environmental impacts.

Doering (2010) provided a detailed overviewof the ICRP framework and the Environmental Risk from Ionising Contaminants Assessment (ERICA) Integrated Approach (as one method of implementing the framework) for radiological assessment and protection of non-human species in Australia.This report discussed in some detail the principles and data requirements underlying the methodology for radiological risk assessments using the ERICA Integrated Approach and the ERICA Tool andtheir applicability to the Australian uranium mining context.This current report will not discuss these frameworks further in any detail.

The RAP approach uses equilibrium concentration ratio – the ratio of radionuclide activity concentration in biota to that in environmental media (e.g. soil, sediment or water) – to estimate the transfer of radionuclides from the environment to non-human biota.The magnitude of the concentration ratio can vary between different radionuclides,biota types and environmental conditions.This means that concentration ratios appropriate to assess biota in one environment type (such as temperate European) may not be appropriate to assess biota in other, dissimilar environments such as desert, arid or wet-dry tropical regions which are more frequently observed in Australian uranium mining areas.

Doering (2010) identified that there is currently no consolidation of existing Australian data on concentration ratio to support non-human biota radiological assessments in the Australian uranium mining context and this impedes the ability of the industry to undertake assessments.The report recommended that further research was required to collect and assemble data on fauna and flora common to major Australian environments in order to establish a set of Australian reference organisms and to facilitate the implementation of the ICRP framework in an Australian context.The report also aimed to promote discussion which may eventually lead to the development of specific national guidance in Australia related to the radiological protection of non-human species, including guidance on specific assessment methods.

The justification for the work detailed in this report arose from the need of the Australian uranium mining industry to demonstrate international best practice standards in environmental assessment, as well as from the current lack of consolidated concentration ratio data to support resonant and technically robust application of a reference animal and plant approach in the Australian uranium mining context.

In August 2011 a Memorandum of Understanding (No. 002097) was signed by the then Department of Resources, Energy and Tourism (DRET) (now DI) and ARPANSA to jointly undertake the project Concentration Ratios for Non-Human Biota inhabiting Australian Uranium Mining Environments.It was agreed that in order to support the implementation of international best practice standards in environmental radiological assessment in Australia, an evaluation of existing data relating to non-human biota inhabiting Australian uranium mining environments should be undertaken, to identify any shortcomings, including biota types and environmental conditions for which data is most lacking, taking into account the location of current and prospective uranium mines in Australia.The report was to include an evaluation of the data and provide recommendations to guide decisions on future work directions.

A Steering Committee (SC) was established in November 2011 to provide strategic direction to the project and to facilitate effective communication with the uranium mining and milling sector and other key stakeholders. This committee was comprised of representatives from DRET and ARPANSA, one invited technical expert from the Environmental Research Institute of the Supervising Scientist (ERISS) and three industry members, nominated by the Australian Uranium Association (AUA) who assisted with facilitating communication with industry and provision of data.

1.2Purpose and Scope

This report provides a summary and evaluation of existing Australian radionuclide activity concentration data in non-human biota common to Australian uranium mining and milling environments.Sources reviewed include data published in peer-reviewed journals, internal government agency reports, data from uranium mining companies and other consultant’s reports that have been produced by a range of organisations over the past 40 years.

Data was evaluated for its suitability for use in calculating whole-organism concentration ratios. Where possible, in the timeframes available to this project, a number of these whole-organism concentration ratios for terrestrial and freshwater wildlife groups have been calculated.An overview of these will be provided.

Any significant data gaps or issues are discussed in order to assist with moving towards establishing a collection of Australianwhole-organism concentration ratios.This will also assist with identification of appropriate Australian reference organisms and the implementation of a framework for assessment and protection of the environment, in an Australian context, which is compatible with international best practice.

1.3Structure

This report consists of four sections and fourappendices.Following this introduction, Section 2 describes the concepts and approach taken in conducting this review.Section 3 outlines the data collection, review and evaluationprocess.Section 4 provides the conclusions and makes some recommendations for future work.

2.Concepts and Approach

2.1Terminologies

2.1.1Non-human biota, non-human species or wildlife?

The term used to refer to species other than humans has varied over the past 20 years.The ICRP use the term ‘non-human species’, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) use non-human biota, and the International Atomic Energy Agency (IAEA) have used a range of terms including, plants and animals (IAEA, 1992); non-human species (IAEA, 2010) and in their most recent document,which is still to be published (IAEA, in press), the IAEA will use the term ‘wildlife’ which relates to living species that are not domesticated and exist in natural habitats.In other publications ‘non-human biota’ has been used but this term is rarely used in ecotoxicology and other areas of environmental protection.It is noted that ARPANSA discussed non-human species in their previous publication on this topic (Doering,2010) however in this current report the term non-human biota will be used, as agreed between DI and ARPANSA in 2011.Non-human biotaincludes any flora or fauna, endemic or introduced, that existsin natural habitats, and specifically in this report, Australian uranium mining or milling environments.This includes domesticated species such as sheep that graze on extensive areas of pastoral lease near uranium deposits or mining areas.Following the finalisation of this report it has been agreed that in the future environmental exposures of wildlife in the natural environment will be the terminology applied in the Australian radiation protection framework (ARPANSA, 2014).

How data on domesticated species such as sheep are utilised when conducting environmental assessments in the future should be considered by the working group that is currently preparing theARPANSA Safety Guide for Radiation Protection of the Environment under the direction of the Radiation Health Committee.

2.1.2Equilibrium concentration ratios

When undertaking radiological risk assessments one of the data components that is essential for such assessments are the organism-to-media concentration ratio (CR) values that are used to estimate whole-organism radionuclide activity concentrations in biota from those in environmental media.The CR values discussed in this report are all assumed to be in equilibrium in the environment between exposed biota and the environmental media which they inhabit.These CR values are particularly appropriate for assessments of long-term exposure scenarios.They are not appropriate for circumstances where there is variation in the radiological conditions (e.g. pulsed inputs of radionuclides or accidents) and alternative methods of quantifying transfer, including dynamic models should be considered.