Nicholas A Beresford

....

....

..There is a clear need to focus efforts and provide authoritative compilations of those data which are available...

..However, the factors are too site specific to be able to generalise the findings to other farms within the restricted areas of the UK...

..A wider discussion of transfer coefficients and concentration ratios leads us to suggest that the concentration ratio is the more robust and potentially generic parameter...

..A field study to determine the activity concentrations of (137)Cs and (239,240)Pu in the milk of ewes grazing a saltmarsh close to Sellafield is also described...

..This paper presents the work of the International Atomic Energy Agency's EMRAS Biota Working Group which compares the predictions of a number of such models in model-model and model-data inter-comparisons...

..Given the uncertainties of conducting a study such as this, the agreement observed between the TLD results and the predicted external dose rates gives confidence to the predictions of the ERICA Tool...

..The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches...

..In a separate paper the outputs of this assessment will be used to estimate doses to reference organisms and compare these to observed radiation induced effects reported within the Chernobyl zone...

....

..Furthermore, there is a need to validate the various methodologies to enable their use with confidence. The requirements of improving our ability to predict radionuclide transfer to wild species are discussed and recommendations made...

..Potential reasons for differences between predictions between the various approaches and the available data are explored...

..Much of this knowledge was obtained during the years of global fallout from atmospheric nuclear weapons tests and the response to the Chernobyl accident, in Ukraine in 1986...

..The use of this technique would negate the need for detailed measurements of the amount of soil adhering to sampled vegetation and soil-specific radiocaesium bioavailability assessments...

..Evidence to suggest that the transfer of radiocaesium to cow milk is considerably higher in the FSU than within western Europe and North America is discussed...

..The lack of agreement highlights the need for further research to establish whether current radiological protection criteria for wildlife are adequate (and to determine if there are any implications for human radiological protection)...

..Potential reasons for these observations are discussed...

..Mean total weighted whole-body absorbed dose rates estimated for the selected terrestrial organisms was in the range 6.9 x 10(-2) to 6.1 x 10(-1) microGy h(-1)...

..Similarly, in dairy cattle, for which feed intake changes considerably during the course of a lactation, large temporal variation in radiocaesium transfer to milk could be expected...

..However, the results of this study demonstrate that, in the event of any future accidental release of radiocaesium, the potential ingestion dose received from the consumption of wild fungi would need to be considered...

..Evaluation of these factors has shown that some previously recommended countermeasures are unlikely to be feasible...

..This work represents a novel implementation of a spatial radioecological model using a Monte-Carlo approach...

..The outputs of the project are described and critically evaluated...

....

..The applicability and usefulness of STRATEGY outputs for food production systems in the medium to long term is assessed...

..The values for domestic ruminants are compared with those derived by the International Commission for Radiological Protection for adult humans...

..However, transfer coefficients will continue to be used as few studies currently report CR values or give data from which they can be estimated...

..Many data gaps remain...

..The intercomparison demonstrated that all participating approaches to biota dose calculation are reasonably comparable, despite a range of different assumptions being made...

..The rate of transfer of (35)S to milk of a further group of goats receiving (35)S-sulphate daily appeared to reach equilibrium within 30 d. Extrapolation of transfer parameters derived to other dairy ruminants is discussed...

..We recommend for screening purposes an F(m) value of 1x10(-5)d l(-1) for Pu, with an order of magnitude lower value being appropriate for cows which are only exposed for one grazing season...