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Keswick, United Kingdom

Ainsbury E.A.,Public Health England | Bakhanova E.,Research Center for Radiation Medicine | Barquinero J.F.,Unitat dAntropologia Biologica | Brai M.,University of Palermo | And 30 more authors.
Radiation Protection Dosimetry

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements. © The Author 2010. Published by Oxford University Press. All rights reserved. Source

Carvalho F.P.,ITN | Oliveira J.M.,ITN | Alberto G.,ITN | Vives i Batlle J.,Westlakes Scientific Consulting Ltd
Marine Pollution Bulletin

Mussels from the Portuguese coast collected during several seasons of the year have shown 210Po and 210Pb body burdens (Bqmussel-1) that increased with mussels' body size but displayed significant decrease in radionuclide concentrations (Bqkg-1). For example, the increase of mussel size from 2.5cm to 5.0cm maximum shell length corresponded in average to a 50% decrease of 210Po activity concentration in soft tissues from 1065Bqkg-1 (dw) to 540Bqkg-1 (dw). A similar reduction in concentration was observed for 210Pb. The physiological condition of mussels, relating to fat and glycogen storage, had an effect on radionuclide concentrations, although the total body burden of radionuclide in mussels remained nearly constant throughout the year. These factors may play an important role in data interpretation for environmental monitoring programmes. Besides the mussel size and condition index, due to the inter-individual variation even inside narrow mussel size classes, the sample size, i.e., the number of specimens in one mussel sample is another key factor to be considered when obtaining environmentally representative radionuclide concentrations. © 2010. Source

Gleizon P.,Westlakes Scientific Consulting Ltd | McDonald P.,Westlakes Scientific Consulting Ltd
Journal of Environmental Radioactivity

In order to support authorised discharges of low level radioactive liquid effluent into coastal regions, mathematical models are required to robustly predict radiological impacts on critical groups of current and proposed changes to liquid discharges. The grid model presented here simulates the long term dispersion and transport of radioactivity discharged from the Sellafield site in Cumbria, UK, and the subsequent exposure of critical groups in Cumbria and across the Irish Sea in Northern Ireland. The fine grid of the model allows a good resolution of the seabed sediment distribution. This benefits the predictions for the last decades of low discharge level, when bed sediment can become a source of contamination by bringing back the legacy of past high discharges. This is highlighted by the dose comparison, where the predicted dose to Cumbria critical group follows well the dose estimated from environmental data during the low discharge level period. © 2010 Elsevier Ltd. Source

Vives I Batlle J.,Westlakes Scientific Consulting Ltd | Wilson R.C.,Westlakes Scientific Consulting Ltd | Watts S.J.,Westlakes Scientific Consulting Ltd | McDonald P.,Westlakes Scientific Consulting Ltd | And 3 more authors.
Radiation and Environmental Biophysics

The basic principles underlying a four-discrete age group, logistic, growth model for the European lobster Homarus gammarus are presented and discussed at proof-of-concept level. The model considers reproduction, removal by predation, natural death, fishing, radiation and migration. Non-stochastic effects of chronic low linear energy transfer (LET) radiation are modelled with emphasis on 99Tc, using three endpoints: repairable radiation damage, impairment of reproductive ability and, at higher dose rates, mortality. An allometric approach for the calculation of LD 50/30 as a function of the mass of each life stage is used in model calibration. The model predicts that at a dose rate of 1 Gy day -1, lobster population reproduction and survival become severely compromised, leading eventually to population extinction. At 0.01 Gy day -1, the survival rate of an isolated population is reduced by 10%, mainly through loss of fecundity, comparable to natural migration losses. Fishing is the main ecological stress and only dose rates in the range 0.03-0.1 Gy day -1 can achieve discernible effects above it. On the balance of radiation and other ecological stresses, a benchmark value of 0.01 Gy day -1 is proposed for the protection of lobster populations. This value appears consistent with available information on radiation effects in wildlife. © 2009 Springer-Verlag. Source

Wilson R.C.,Westlakes Scientific Consulting Ltd | Vives I Batlle J.,Westlakes Scientific Consulting Ltd | Watts S.J.,Westlakes Scientific Consulting Ltd | McDonald P.,Westlakes Scientific Consulting Ltd | And 2 more authors.
Radiation and Environmental Biophysics

A conceptual model of the effects of chronic radiation on a population of phytoplankton and zooplankton in an oceanic nutrient layer is presented. The model shows that there are distinct threshold dose rates at which the different plankton populations become unsustainable. These are 10,400 μGy h -1 for phytoplankton and 125 μGy h -1 for zooplankton. Both these values are considerably greater than the current screening values for protection of 10 μGy h -1. The model highlights the effects of predator-prey dynamics in predicting that when the zooplankton is affected by the radiation dose, the phytoplankton population can increase. In addition, the model was altered to replicate the dose rates to the plankton of a previous ERICA Irish Sea assessment (24 μGy h -1 for zooplankton and 430 μGy h -1 to phytoplankton). The results showed only a 10% decrease in the zooplankton population and a 15% increase in the phytoplankton population. Therefore, at this level of dose, the model predicts that although the dose rate exceeds the guideline value, populations are not significantly affected. This result highlights the limitations of a single screening value for different groups of organisms. © 2009 Springer-Verlag. Source

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