Derivation of regional hazardous doses for amphibians acutely exposed to ionising radiation

Estimation of 50% lethal doses from nuclear DNA contents and subsequent species sensitivity distribution analysis was performed to derive regional 5% hazardous doses (HD5) for major orders Anura (e.g., frogs) and Caudata (e.g., salamanders) of amphibians inhabiting Japan, Australia, France, Czech Republic, Canada and some US states, where nuclear power plants or uranium mines are located. The HD5 values ranged from 3.0 to 7.7Gy for the Anura inhabiting there while they ranged from 2.9 to 4.6Gy for the Caudata. Comparison of these results with the worldwide HD5s (5.3Gy for the Anura and 3.3Gy for the Caudata) suggests that benchmark values for the Asian and Oceanic Anura and the European Caudata can be set at higher doses than the global values. Regional differences should be, therefore, considered when benchmark values are derived for some taxonomic groups.