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Conceptual, mathematical and simulation models are important and exciting, because they capture general principles of a scientific area and because they can make predictions.This website is about the development of ecotoxicological models, the research focus of my team.

 

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Roman Ashauer

 

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Importance of Toxicokinetics for Interspecies Variation in Sensitivity to Chemicals

Imaging the distribution of a pesticide in a freshwater snail and a shrimp. Credit: Eawag/Harlan Laboratories
Imaging the distribution of a pesticide in a freshwater snail and a shrimp. Credit: Eawag/Harlan Laboratories

Interspecies variation in sensitivity to synthetic chemicals can be orders of magnitude large. Species traits causing the variation can be related to toxicokinetics (uptake, distribution, biotransformation, elimination) or toxicodynamics (interaction with biological target sites). We present an approach to systematically measure and model the contribution of uptake, biotransformation, internal distribution, and elimination kinetics toward species sensitivity differences. The aim is to express sensitivity as target tissue specific, internal lethal concentrations. A case study with the pesticides diazinon, imidacloprid, and propiconazole and the aquatic invertebrates Gammarus pulex, Gammarus fossarum, and Lymnaea stagnalis illustrates the approach. L. stagnalis accumulates more pesticides than Gammaridae when measured in whole organisms but less in target tissues such as the nervous system. Toxicokinetics, i.e. biotransformation and distribution, explain the higher tolerance of L. stagnalis to the insecticide diazinon when compared to Gammaridae. L. stagnalis was again more tolerant to the other neurotoxicant imidacloprid; however, the difference in sensitivity could not be explained by toxicokinetics alone, indicating the importance of toxicodynamic differences. Sensitivity to propiconazole was comparable among all species and, when expressed as internal lethal concentrations, falls in the range of baseline toxicity. (published in Environmental Science & Technology)

Importance of Toxicokinetics for Interspecies Variation in Sensitivity to Chemicals
37 Importance of toxicokinetics for inte
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