A method for assessing exposure of terrestrial wildlife to environmental radon ( 222 Rn) and thoron ( 220 Rn)

A method is presented to calculate radiation dose rates arising from radon, thoron and their progeny to non-human biota in the terrestrial environment. The method improves on existing methodologies for the assessment of radon to biota by using a generalised allometric approach to model respiration, calculating dose coefficients for the ICRP reference animals and plants, and extending the approach to cover thoron in addition to radon-derived isotopes. The method is applicable to a range of environmental situations involving these radionuclides in wildlife, with an envisaged application being to study the impact of human activities, which bring NORM radionuclides to the biosphere. Consequently, there is a need to determine whether there is an impact on non-human biota from exposure to anthropogenically enhanced radionuclides

Marine radioecology after the Fukushima Dai-ichi nuclear accident : are we better positioned to understand the impact of radionuclides in marine ecosystems?

© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Science of The Total Environment 618 (2017): 80-92, doi:10.1016/j.scitotenv.2017.11.005.This paper focuses on how a community of researchers under the COMET (CO-ordination and iMplementation of a pan European projecT for radioecology) project has improved the capacity of marine radioecology to understand at the process level the behaviour of radionuclides in the marine environment, uptake by organisms and the resulting doses after the Fukushima Dai-ichi nuclear accident occurred in 2011. We present new radioecological understanding of the processes involved, such as the interaction of waterborne radionuclides with suspended particles and sediments or the biological uptake and turnover of radionuclides, which have been better quantified and mathematically described. We demonstrate that biokinetic models can better represent radionuclide transfer to biota in non-equilibrium situations, bringing more realism to predictions, especially when combining physical, chemical and biological interactions that occur in such an open and dynamic environment as the ocean. As a result, we are readier now than we were before the FDNPP accident in terms of having models that can be applied to dynamic situations. The paper concludes with our vision for marine radioecology as a fundamental research discipline and we present a strategy for our discipline at the European and international levels. The lessons learned are presented along with their possible applicability to assess/reduce the environmental consequences of future accidents to the marine environment and guidance for future research, as well as to assure sustainability of marine radioecology in Europe and globally. This guidance necessarily reflects on why and where further research funding is needed, signalling the way for future investigations.The research leading to this paper has received funding from the European Union's seventh Framework programme (FP7/2007-2013) under grant agreement No. is 604974 (Projects within COMET: Marine Initial Research Activity and The impact of recent releases from the Fukushima nucleaR Accident on the Marine Environment - FRAME). Sampling off Japan has been supported by the Gordon and Betty Moore Foundation, the Deerbrook Charitable Trust and contributions to the WHOI Centre for Marine and Environmental Radioactivity. We acknowledge the JSPS KAKENHI Grant-in-Aid for Scientific Research on Innovative Areas Grant No. 24110005 for supporting in part the activities during the research cruises to the FDNPP area

Modelling the exposure of wildlife to radiation: key findings and activities of IAEA working groups

The International Atomic Energy Agency (IAEA) established the Biota Working Group (BWG) as part of its Environmental Modelling for Radiation Safety (EMRAS) programme in 2004 (http://www-ns.iaea.org/projects/emras/emras-biota-wg.htm). At that time both the IAEA and the International Commission on Radiological Protection (ICRP) were addressing environmental protection (i.e. protection of non-human biota or wildlife) within the on-going revisions to the Basic Safety Standards and Recommendations respectively. Furthermore, some countries (e.g. the USA, UK) were already conducting assessments in accordance with national guidelines. Consequently, a number of assessment frameworks/models had been or were being developed. The BWG was established recognising these developments and the need to improve Member State’s capabilities with respect to protection of the environment from ionizing radiation. The work of the BWG was continued within the IAEA’s EMRAS II programme by the Biota Modelling Group (http://wwwns. iaea.org/projects/emras/emras2/working-groups/working-group-four.asp)

Making the most of what we have: Application of extrapolation approaches in radioecological wildlife transfer models

© 2015 The Authors. We will never have data to populate all of the potential radioecological modelling parameters required for wildlife assessments. Therefore, we need robust extrapolation approaches which allow us to make best use of our available knowledge. This paper reviews and, in some cases, develops, tests and validates some of the suggested extrapolation approaches.The concentration ratio (CRproduct-diet or CRwo-diet) is shown to be a generic (trans-species) parameter which should enable the more abundant data for farm animals to be applied to wild species.An allometric model for predicting the biological half-life of radionuclides in vertebrates is further tested and generally shown to perform acceptably. However, to fully exploit allometry we need to understand why some elements do not scale to expected values.For aquatic ecosystems, the relationship between log10(a) (a parameter from the allometric relationship for the organism-water concentration ratio) and log(Kd) presents a potential opportunity to estimate concentration ratios using Kd values.An alternative approach to the CRwo-media model proposed for estimating the transfer of radionuclides to freshwater fish is used to satisfactorily predict activity concentrations in fish of different species from three lakes. We recommend that this approach (REML modelling) be further investigated and developed for other radionuclides and across a wider range of organisms and ecosystems.Ecological stoichiometry shows potential as an extrapolation method in radioecology, either from one element to another or from one species to another.Although some of the approaches considered require further development and testing, we demonstrate the potential to significantly improve predictions of radionuclide transfer to wildlife by making better use of available data

COMET deliverable (D-No. 1.5). COMET project final report: advancement in science, integration and sustainability of European radioecology

The EC FP7 COMET (Coordination and iMplementation of a pan-European instrument for radioecology) was funded to strengthen the pan-European research initiative on the impact of radiation on man and the environment by facilitating the integration of radioecology research and development

One year on: some thoughts about the ecological fallout from Fukushima

Damage to nuclear reactors and buildings at the Fukushima Daiichi nuclear power plant following the earthquake and subsequent tsunami that struck Japan on March 11, 2011, resulted in the second-largest release of radioactive substances into the environment since the start of nuclear power production, and the largest accidental releases in history to the marine environment. Only the Chernobyl disaster surpassed it in magnitude

Allometric methodology for the assessment of radon exposures to terrestrial wildlife

A practical approach to calculate 222Rn daughter dose rates to terrestrial wildlife is presented. The method scales allometrically the relevant parameters for respiration in different species of wildlife, allowing inter-species calculation of the dose per unit radon concentration in air as simple base-and-exponent power functions of the mass. For plants, passive gas exchange through the leaf surface is assumed, also leading to specific power relationships with mass. The model generates conservative predictions in which the main contributor to the dose rate of target tissues of the respiratory system is from α radiation arising from 222Rn daughters. Tabulated 222Rn DPURn values are given for 69 species used by the England & Wales Environment Agency for habitats assessments. The approach is then applied to assess the authorised discharges of 222Rn from sites in England, demonstrating that, from a whole-body dose perspective, the biota considered are protected from effects at the population level

A method for estimating 41Ar, 85,88Kr and 131m,133Xe doses to non-human biota

A method is presented for estimating 41Ar, 85,88Kr and 131m,133Xe dose rates to terrestrial wildlife without having to resort to comparisons with analogue radionuclides. The approach can be used to calculate the dose rates arising from external exposures to given ambient air concentrations of these isotopes. Dose conversion coefficient (DCC) values for a range of representative organisms are calculated, using a Monte Carlo approach to generate absorbed fractions based on representing animals as reference ellipsoid geometries. Plume immersion is the main component of the total DCC. DCC values calculated for a human-sized organism are compared with human dose conversion factors from ICRP Publication 119, demonstrating the consistency of the biota approach with that for humans. An example of application is provided for hypothetical nuclear power plant atmospheric discharges with associated exposures to birds and insects. In this example, the dose rates appear to be dominated by 133Xe and 88Kr, respectively. The biota considered would be protected from the effects of noble gas radiation from a population protection perspective