Selecting passive dosimetry technologies for measuring the external dose of terrestrial wildlife

Dosimetersattached to wild animals can be used to validate regulatory assessment approaches and models for estimating radiation exposure of wild animals. Such measurements are also necessary to ensure that robust dose-effect relationships can be developed from the results of field research programmes. This paper presents the first comprehensive evaluation of the different dosimetrytechnologies available for specifically measuring the external exposure of wildlife. Guidance is provided on the selection of appropriate passive dosimetryapproaches for directly measuring external exposure of terrestrial wildlifeunder field conditions. The characteristics and performance of four available dosimetrytechnologies ( thermoluminescent dosimeter(TLD), optically stimulated luminescent dosimeter(OSLD), radiophotoluminescent dosimeter(RPLD) and direct ion storage, (DIS)) are reviewed. Dosimeterproperties, detection limit and dose range, studyorganisms and the intended application are variables that need to be considered when selecting a suitable dosimetrytechnology. Evaluated against these criteria, it is suggested that LiF based and Al2O3:C TLDs, OSLD and RPLD could all be used to estimate doses to wildlife. However, only LiF based TLDs have been used to directly measure wildlifedoses in field studies to date. DIS is only suitable for comparatively large species (e.g. medium to large mammals), but has the advantage that temporal variation in dose can be recorded. In all cases, dosimetercalibration is required to ensure that the dose measurements reported can be interpreted appropriately for the organisms of interest.