Time resolved effect model for Daphnia magna – Measurement and modeling of the toxicokinetic phase of diazinon

Kretschmann, Andreas, Ashauer, Roman, Fenner, Kathrin, Spaak, Piet, Hollender, Julian and Escher, Beate (2009). Time resolved effect model for Daphnia magna – Measurement and modeling of the toxicokinetic phase of diazinon. In: SETAC Europe 19th Annual Meeting Protecting ecosystem health: facing the challenge of a globally changing environment, Convention Centre in Goteborg, Sweden, (). 31 May - 4 June 2009.


Author Kretschmann, Andreas
Ashauer, Roman
Fenner, Kathrin
Spaak, Piet
Hollender, Julian
Escher, Beate
Title of paper Time resolved effect model for Daphnia magna – Measurement and modeling of the toxicokinetic phase of diazinon
Conference name SETAC Europe 19th Annual Meeting Protecting ecosystem health: facing the challenge of a globally changing environment
Conference location Convention Centre in Goteborg, Sweden
Conference dates 31 May - 4 June 2009
Publication Year 2009
Sub-type Oral presentation
Open Access Status
Abstract/Summary The goal of this project is the development of a time-resolved effect model for the water flea Daphnia magna which describes toxic effects of insecticides as function of toxicokinetic and toxicodynamic processes. The novelty of the approach lies in the identification and quantification of the insecticide and its metabolites formed during the toxicokinetic phase inside of the organism. The organophosphorous insecticide diazinon serves as a model compound, the water flea Daphnia magna is chosen as a model organism. In this presentation, we will show results of the analysis of the toxicokinetic phase of diazinon in Daphnia magna. The toxicokinetic phase of diazinon consists of the passive uptake/ elimination of diazinon into/ out of the organism, oxidation to the active metabolite diazoxon by cytochrome P450, hydrolysis to 2-isopropyl-6-methyl-4-pyrimidinol and further elimination processes catalysed by different enzymes. The metabolites themselves can be eliminated by hydrolysis, conjugation or passive diffusion. In in vivo experiments Daphnia magna was exposed to the insecticide diazinon. After different exposure times the internal concentration of the parent compound as well as of the metabolites were measured with HPLC-MS/MS. The rate constants of the different toxicokinetic steps were obtained by modeling the time course of the internal concentrations with a multi-component first-order kinetics model. The results show that the dominating elimination step of diazinon is the oxidation to diazoxon. Diazoxon could only be detected in very low concentrations between the limit of detection and quantification. A possible explanation for this are elimination processes which are very fast compared to the parent compound diazinon.
Keyword Daphnia magna
toxicokinetic
diazinon
Q-Index Code EX
Q-Index Status Provisional Code

Document type: Conference Paper
Collection: National Research Centre for Environmental Toxicology Publications
 
Versions
Version Filter Type
Citation counts: Google Scholar Search Google Scholar
Created: Thu, 15 Apr 2010, 09:42:28 EST by Manjit Sanghera on behalf of National Res Centre For Environmental Toxicology