The General Unified Threshold models of Survival (GUTS) are today recognized as ready-to-use tools for Environmental Risk Assessment (ERA), in particular for use in the risk assessment of pesticides on aquatic fauna (EFSA PPR Panel, 2018). These models translate time‐variable chemical exposure information into expected survival of organisms over time. They are species and compound specific and explicitly describe the internal exposure dynamics within a whole organism (toxico-kinetics, TK) and the related damage and effect dynamics (toxico-dynamics, TD). Regarding the TK part, considering organisms as a whole prevents a full understanding of physiological functions (namely, organs) that are really impaired during exposure. The current ANR project APPROve has specifically set itself the objective of delineating the fate of chemical compounds within organisms in order to improve the link with the TD part. To this end, the sentinel species Gammarus fossarum has been chosen as well as three metals for which internal concentrations within several expected target organs are followed over time, in combination with the measurement of classical life history traits, like survival. And an innovative organ-based TK model (namely a PBTK model) has newly been developed that needs now to be related to the TD part.
The main objective of this internship is to refine GUTS models, used in their reduced version as recommended by EFSA, in order to combine the above-mentioned PBTK model to the TD part based on survival data for G. fossarum exposed to cadmium.