Toxicokinetic-toxicodynamic modelling of survival of Gammarus pulex in multiple pulse exposures to propiconazole: model assumptions, calibration data requirements and predictive powerReport as inadecuate




Toxicokinetic-toxicodynamic modelling of survival of Gammarus pulex in multiple pulse exposures to propiconazole: model assumptions, calibration data requirements and predictive power - Download this document for free, or read online. Document in PDF available to download.

Ecotoxicology

, Volume 21, Issue 7, pp 1828–1840

First Online: 05 May 2012Accepted: 12 April 2012

Abstract

Toxicokinetic-toxicodynamic TKTD models quantify the time-course of internal concentration, which is defined by uptake, elimination and biotransformation TK, and the processes which lead to the toxic effects TD. TKTD models show potential in predicting pesticide effects in fluctuating concentrations, but the data requirements and validity of underlying model assumptions are not known. We calibrated TKTD models to predict survival of Gammarus pulex in propiconazole exposure and investigated the data requirements. In order to assess the need of TK in survival models, we included or excluded simulated internal concentrations based on pre-calibrated TK. Adding TK did not improve goodness of fits. Moreover, different types of calibration data could be used to model survival, which might affect model parameterization. We used two types of data for calibration: acute toxicity standard LC50, 4 d or pulsed toxicity data total length 10 d. The calibration data set influenced how well the survival in the other exposure scenario was predicted acute to pulsed scenario or vice versa. We also tested two contrasting assumptions in ecotoxicology: stochastic death and individual tolerance distribution. Neither assumption fitted to data better than the other. We observed in 10-d toxicity experiments that pulsed treatments killed more organisms than treatments with constant concentration. All treatments received the same dose, i.e. the time-weighted average concentration was equal. We studied mode of toxic action of propiconazole and it likely acts as a baseline toxicant in G. pulex during 10-days of exposure for the endpoint survival.

KeywordsOrganism recovery Delayed toxicity Dose response model Pesticide risk assessment Bioaccumulation Electronic supplementary materialThe online version of this article doi:10.1007-s10646-012-0917-0 contains supplementary material, which is available to authorized users.

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Author: Anna-Maija Nyman - Kristin Schirmer - Roman Ashauer

Source: https://link.springer.com/







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