Element

Considerations

Exposure of biota

•  Spatial and temporal patterns of radionuclide in environment in material;

•  Uptake by organism;

•  Non-uniform distribution within organism.

Reference biota

•  Not possible to evaluate all biota;

•  Need to select reference biota or indicator species appropriate for area of interest and desirable basis for selection;

•  Possible need consider individuals biota per se when species are endangered.

Dosimetry model for reference biota

•  Absorbed dose (to whole body or to tissue/organ);

•  Geometry corrections;

•  Relative biological effectiveness (RBE): the effects of different qualities of radiation on biota.

Endpoints in radiological assessment

•  Selection of appropriate population level (deterministic) “umbrella” effects such as mortality or reproductive capacity and corresponding references doses.

Effects on biota

•  Connection between radiation effects on “umbrella” endpoint in individual, and consequent “possible” effects on population;

•  Role of background radiation levels;

•  Natural population variability.