Transfer models for reference Arctic biota: A review of the available literature has shown that there are few Arctic-specific concentrations ratios for freshwater biota. However, a proven dynamic model is available for describing the behaviour of selected radionuclides in abiotic and biotic components of freshwater ecosystems. For some radionuclides (Cs, Sr, P, Mn, Zn, I and Co) rates of uptake by fish are modelled using temperature dependent and ECOMOD includes some parameters derived from northern Russian lakes. These aspects of ECOMOD can therefore be said to be applicable to the Arctic. However, for other radionuclides and for invertebrates and aquatic plants non-Arctic specific empirical transfer ratios have to be used. Aquatic mammals and birds are not considered within the existing model. Although we have only considered modelling approaches for Arctic lakes these could be adapted to Arctic rivers in combination with an appropriate a river transport model.
Marine
Concentration factors values for many marine biota are available within international reviews. Whilst these tend to be for edible tissues it is possible that in some cases they could be transformed into whole body burdens using published distributions of radionuclides within organisms. However, they are not specific to the Arctic where transfer may be influenced by environmental factors such as low temperature, seasonal variation in light intensity and ice cover.
Arcticspecific data have been collated for Cs, Pu, Sr and Tc from the open literature and are recommended to be used as supplementary information, although, in general, the collated Arctic concentration factors are similar to those for temperate environments.
Dynamic models have been used for the prediction of radionuclide activity concentrations in Arctic marine species has been demonstrated. Allometric relationships have been used in several cases where empirical data were unavailable for model parameterisation. The preliminary model appears to give reasonable predictions for 137Cs and 239Pu and demonstrates the fact that high trophic level organism may take very long time periods to become equilibrated with ambient water concentrations. Such an approach could also be used to provide missing data for Arctic freshwater ecosystems.
Marine contaminant transport models, some of which have been applied to the Arctic and include parameters of ice flow and formation, are reviewed.
Terrestrial
Data describing the transfer of radionuclides from soilreference biota have been collated. The most abundant data were for radiocaesium and radiostrontium although many data for natural radionuclides were available from studies from the Arctic. No data were available for describing the transfer of some radionuclides to Arctic biota.
Allometric-kinetic models were also used to try to provide estimates of transfer for radionuclide-biota combinations for which data were lacking using, where possible, soilplant transfer parameters derived during the review. Predicted values were in good agreement with observed data for some radionuclides (e.g. Cs, U) although less so for others. However, for some radionuclides where comparison appeared poor there was relatively little observed data with which to compare and the developed models were very simplistic not considering all transfer pathways.
There are no bespoke models to enable the dynamic prediction of radionuclide transfer to Arctic biota. One available human foodchain model includes limited parameterisation for Cs and Sr transfer in Arctic ecosystems. This has been relatively easily adapted to estimate 137Cs and 90Sr transfer to some Arctic biota and could be readily adapted to other radionuclide reference organism combinations. However, there are many factors of Arctic ecosystems, which may influence radionuclide behaviour including short growing seasons, prolonged freezing of soil, and effects of low temperatures on biological rates. However, whilst the influence of some of these has been documented, they are not included within existing predictive models. If exposure to ionising radiation within Arctic terrestrial ecosystems is to be robustly predicted such factors must be fully understood and properly incorporated into models. Dosimetric models for reference Arctic biota: The new methodology, algorithms and the first version of the computer program for an estimation of internal and external exposure of various biota representatives are developed. The dose coefficients for 42 radionuclides of natural and artificial origin at various variants of external and internal exposures of biota in terrestrial and aquatic environments are calculated. At present time the first version of the computer program allowing carry out of such calculations is prepared. The methodology and algorithms of calculation can be used by the scientists engaged in researches in the field of radiation protection of an environment and by the decision makers in a case of radioactive environmental contamination.