(1) Collate information relating to the environmental transfer and fate of selected radionuclides through aquatic and terrestrial ecosystems in the Arctic. (2) Identify reference Arctic biota that can be used to evaluate potential dose rates to biota in different terrestrial, freshwater and marine environments (3) Model the uptake of a suite of radionuclides, both natural and anthropogenic to reference Arctic biota (4) Develop a reference set of dose models for reference Arctic biota (5) Compile data on dose-effects relationships and assessments of potential radiological consequences for reference Arctic biota (6) Integrate assessments of environmental impact from radionuclides with those for other contaminants.