TRansfer - Exposure - Effects (TREE): integrating the science needed to underpin radioactivity assessments for humans and wildlife

For all sources of radioactivity, radiological risk assessments are essential for safeguarding human and environmental health. But assessments often have to rely upon simplistic assumptions, such as the use of simple ratios in risk calculations which combine many processes. This pragmatic approach has largely arisen due to the lack of scientific knowledge and/or data in key areas. The resultant uncertainty has been taken into account through conservative approaches to radiological risk assessment which may tend to overestimate risk. Uncertainty arises at all stages of the assessment process from the estimation of transfer to human foodstuffs and wildlife, exposure and risk. Reducing uncertainty is important as it relates directly to scientific credibility, which will always be open to challenge given the highly sensitive nature of radiological risk assessment in society. We propose an integrated, multi-disciplinary, programme to assess and reduce the uncertainty associated with radiological risk assessment to protect human health and the environment. At the same time we will contribute to building the capacity needed to ensure that the UK rebuilds and maintains expertise in environmental radioactivity into the future.
Our project has four major and highly inter-related components to address the key goal of RATE to rebuild UK capacity and make a major contribution to enhancing environmental protection and safeguarding human health.
The first component will study how the biological availability of radionuclides varies in soils over time. We will investigate if short-term measurements (collected in three year controlled experiments) can be used to predict the long-term availability of radionuclides in soils by testing our models in the Chernobyl exclusion zone. The second component will apply the concepts of 'phylogeny' and 'ionomics' to characterise radionuclide uptake by plants and other organisms. These approaches, and statistical modelling methods, are increasingly applied to describe uptake of a range of elements in plant nutrition, and we are pioneering their use for studying radionuclide uptake in other organisms and human foods. A particularly exciting aspect of the approach is the possibility to make predictions for any plant or animal. This is of great value as it is impossible to measure uptake for all wildlife, crops and farm animals. The third component of the work will extend our efforts to improve the quantification of radiation exposure and understanding of resultant biological effects by investigating the underlying mechanisms involved. A key aim is to see whether what we know from experiments on animals and plants in the laboratory is a good representation of what happens in the real world: some scientists believe that animals in the natural environment are more susceptible to radiation than laboratory animals: we need to test this to have confidence in our risk assessments. Together these studies will enable us to reduce and better quantify the uncertainties associated with radiological risk assessment.
By training a cohort of PDRA and PhDs our fourth component will help to renew UK capacity in environmental radioactivity by providing trained, experienced researchers who are well networked within the UK and internationally through the contacts of the investigators. Our students will be trained in a wide range of essential skills through their controlled laboratory studies and working in contaminated environments. They will benefit from being a member of a multidisciplinary team and opportunities to take placements with our beneficiaries and extensive range of project partners.
The outputs of the project will benefit governmental and non-governmental organisations with responsibility for assessing the risks to humans and wildlife posed by environmental radioactivity. It will also make a major contribution to improved scientific and public confidence in the outcomes of environmental safety assessments.

Nuclear new-build and waste disposal require rigorous safety assessments of effects on the biosphere and human health to underpin decisions which often involve public consultation. The credibility of scientific evidence is open to challenge given the sensitive nature of radiological risk assessment. The publicity (www.bbc.co.uk/news/science-environment-10819027) associated with scientific dispute on the environmental effects of radiation hinders informed debate on nuclear issues and will impinge upon the economic competitiveness of the UK by delaying decisions on future energy supplies and disposal. Unbiased scientific opinion, based on rigorous research, and demonstration of fitness for purpose of assessment approaches will aid debate in the UK and overseas thereby directly supporting the public, regulators and industry.
This project addresses 4 of the 5 priority areas identified by the RATE programme ensuring we will make major contributions to the programme's objectives. We will produce capacity that will benefit the RCUK Energy Plan whilst producing innovative, excellent science that will also underpin the commercial sector.
The consortium partners represent a significant proportion of current UK capability in the key radioecological fields identified by RATE. As part of the project, 4 PDRAs and a cohort of 7 PhD students with the skills to build on this capacity will be trained, enhancing the UK research capability and providing skilled practitioners for industry/regulators. Our summer school at Chernobyl and training programme will be open to PhD students from all RATE consortia, the European STAR radioecology Network of Excellence and our project partners.
NDA and EA will benefit from reduced uncertainty in wildlife and human assessment models. Key radionuclides identified in geological repositories assessments are the focus of soil-plant biogeochemical studies and development of phylogenetic models to predict activity concentrations in wildlife and human foodchain models. New data and phylogenetic-ionomic models will significantly improve transfer models for Reference Animals and Plants (RAPs). They also have the potential to identify suitable surrogates for protected species for environmental monitoring and to be applicable to human and environmental assessment.
In particular EA will also benefit from the effects data obtained for some RAPs which will help fitness-for-purpose assessment of the ICRP's Derived Consideration Reference Levels. An improved understanding of biological effect mechanisms of radiation will be gained including the evaluation of trans-generation effects and how this may impact on populations. These outputs will feed into the derivation of robust, scientifically defensible numeric criteria for use in wildlife dose assessments at an international level and will expand basic knowledge on chronic low level radiation effects.
SEPA will benefit from improved approaches and reduced/quantified uncertainties for environmental and human foodchain assessments. Equivalent overseas agencies will similarly benefit through our input to key international organisations. For instance, the IAEA and ICRP who provide the guidance and recommendations on radiation protection used to define regulation at European and national levels. International guidance for ensuring the environment is protected from releases of radioactive substances is still developing and the outputs from TREE will provide key inputs. Close engagement of consortium members with national and international agencies and other beneficiaries will ensure that impacts will be realised immediately. Benefits will continue to be realised, and project outputs exploited, as international organisations and national regulators develop recommendations and decisions are made on nuclear related issues using the improved knowledge from this project.