WP1: Toxicokinetics-toxicodynamics of a bivariate pesticide mixture on earthworm life history
Rationale: The physiological mode of action of the bivariate pesticide mixture and its effect on critical endpoints must first be characterized at the population level before more precise effects among individuals are evaluated in subsequent work packages.
Approach: We will measure the effects of a bivariate mixture of epoxiconazole and imidacloprid on earthworm growth, reproduction and burrowing activity using existing protocols for evaluating mixture’s effects on survival. We will expose earthworms from the EcoSys laboratory culture to four concentrations of both pesticides along with controls in a full-factorial design. Next, we will measure the effect of the mixture on earthworm key life-history traits: growth, reproduction and burrowing activity along with carbon mineralization rates and soil aggregation. This step will allow to calibrate a TKTD model for the mixture, accounting for possible synergistic or antagonistic effects. Pesticide concentrations in the soil and earthworms will be monitored as well to provide additional data on the mixture’s toxicokinetics. This WP will allow to gather critical knowledge on the modes of action of the pesticide mixture and its threshold concentrations on key life-history endpoints.
