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

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

by

Gillian Hirth

frame1

Table of Contents

Acknowledgements iii

Executive Summary iv

Introduction 1

1.1Background 1

1.2Purpose and Scope 3

1.3Structure 3

Concepts and Approach 4

1.4Terminologies 4

1.5International Initiatives 6

1.6Australian Uranium Mining Environments 7

Data Collection, Review and Evaluation 10

1.7Data Collection 10

1.8Data Review and Evaluation 11

1.9Data Manipulation 11

1.10Issues Arising 13

Conclusions 18

1.11Recommendations 18

References 20

Appendix 1Reports and Publications Reviewed 22

Appendix 2Conversion Factors 25

Appendix 3Australian Whole-organism CR – Current 26

Appendix 4Summary of Data Identified During Project 31

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 Mr Frank Harris, Ms Katrina James and Ms Kathryn Taylor.

The author would also like to thank Ches Mason, Barbara Radcliffe and Jim Hondros (BHP Billiton) for the time spent reviewing archives to provide data for this project; and Mat 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 review of this report.

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 activities have 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), the Department of Industry (DI) and ARPANSA 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. 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 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. 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. This has 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 (K_d) 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:

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.
The cooperative relationship with industry undertaken during this project is further 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.
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.
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.
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 done in a coordinated manner with industry, research bodies and relevant Commonwealth agencies.

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