title: Demographic Toxicokinetic-Toxicodynamic Modeling of Lethal Effects.
abstract: The aquatic effect assessment of chemicals is largely based on standardized measures of toxicity determined in short-term laboratory tests which are designed to reduce variability. For this purpose, uniform individuals of a species are kept under environmental and chemical exposure conditions which are as constant as possible. In nature, exposure often appears to be pulsed, effects might last longer than a few days, sensitivity might vary among different sized organisms and populations are usually size or age structured and are subject to demographic processes. To overcome this discrepancy, we tested toxicokinetic-toxicodynamic models of different complexities, including body size scaling approaches, for their ability to represent lethal effects observed for Daphnia magna exposed to triphenyltin. The consequences of the different toxicokinetic and toxicodynamic assumptions for population level responses to pulsed exposure are tested by means of an individual based model and are evaluated by confronting model predictions with population data for various pulsed exposure scenarios. We provide an example where increased model complexity reduces the uncertainty in model outputs. Furthermore, our results emphasize the importance of considering population demography in toxicokinetics and toxicodynamics for understanding and predicting potential chemical impacts at higher levels of biological organization.
authors.affiliation: Research Institute for Ecosystem Analysis and Assessment (gaiac) , Kackertstraße 10, 52072 Aachen, Germany.|Institute for Environmental Research, RWTH Aachen University , Worringer Weg 1, 52074 Aachen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Gergs
authors.affiliation: Institute for Environmental Research, RWTH Aachen University , Worringer Weg 1, 52074 Aachen, Germany.|RIFCON GmbH , Goldbeckstraße 13, 69493 Hirschberg, Germany.
authors.forename: Faten
authors.initials: F
authors.lastname: Gabsi
authors.affiliation: Institute for Ecopreneurship, School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland , Gründenstrasse 40, 4132 Muttenz, Switzerland.
authors.forename: Armin
authors.initials: A
authors.lastname: Zenker
authors.affiliation: Bayer CropScience , Alfred-Nobel-Straße 50, 40789 Monheim am Rhein, Germany.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Preuss
mesh_terms: D000818:Animals; D049628:Body Size; D003621:Daphnia / Q000187:drug effects; D003710:Demography; D018570:Risk Assessment; D066007:Toxicokinetics