LAUSR

Ecotoxicity data constitute the basic information to support the derivation of ecological benchmark values, whatever the stressor concerned. However the set of appropriate data may be limited, especially with regard to chronic exposure conditions. The available data are often biased in favor of acute data from laboratory controlled conditions, much easier to acquire. To make the best use of the available knowledge and better inform effects of ionizing radiation chronic exposure on non-human species, we investigated the transposition to ionizing radiation ecotoxicity of one method proposed for chemicals to extrapolate chronic information from acute toxicity data. Such a method would contribute to enrich chronic data sets required for the derivation of benchmark values making them more robust when used as reference values for ecological risk assessment. We developed accordingly the ACTR (Acute to Chronic Transformation for Radiotoxicity data) approach which we validated. We introduced then the new concept of Endpoint Sensitivity Distribution (ESD). This finally allowed us to compare purely chronic and ACTR-built ESDs for different taxa. For some of them, predicted and observed distributions looked very similar. This promising ACTR method appeared applicable with a reasonable level of confidence, but its generalization asks for improvements, some being already identified.