A method for estimating 41Ar, 85,88Kr and 131m,133Xe doses to non-human biota

A method is presented for estimating 41Ar, 85,88Kr and 131m,133Xe doses to terrestrial wildlife without having to resort to comparisons with analogue radionuclides. The approach can be used to calculate the dose rates arising from external exposures to given ambient air concentrations of these isotopes. Dose conversion coefficient (DCC) values for a range of representative organisms are calculated, using a Monte Carlo approach to generate absorbed fractions based on representing animals as reference ellipsoid geometries. Plume immersion is the main component of the total DCC. DCC values calculated for a human-sized organism are compared with human dose conversion factors from ICRP Publication 119, demonstrating the consistency of the biota approach with that for humans. An example of application is provided for hypothetical nuclear power plant atmospheric discharges with associated exposures to birds and insects. In this example, the dose rates appear to be dominated by 133Xe and 88Kr, respectively. The biota considered would be protected from the effects of noble gas radiation from a population protection perspective.