Demonstrating the need for chemical exposure characterisation in a microplate test system: Toxicity screening of sixteen pesticides on two marine microalgae

Type Article
Date 2019-04
Language English
Author(s) Dupraz Valentin1, 2, Stachowski-Haberkorn SabineORCID1, Wicquart Jérémy1, Tapie Nathalie3, 4, Budzinski Hélène3, 4, Akcha Farida1
Affiliation(s) 1 : Ifremer, Laboratoire d’Écotoxicologie, rue de l’île d’Yeu, BP 21105, F-44311 Nantes Cedex 03, France
2 : Université de Nantes, UFR Sciences et Techniques, 2, rue de la Houssinière, BP 92208, 44322 Nantes Cedex 03, France
3 : Université de Bordeaux, UMR 5805, EPOC, Laboratoire de Physico Toxico Chimie de l'environnement, 351 Cours de la Libération, CS 10004, F-33405 Talence Cedex, France
4 : CNRS, UMR 5805, EPOC, Laboratoire de Physico Toxico Chimie de l'environnement, 351 Cours de la Libération, CS 10004, F-33405 Talence Cedex, France
Source Chemosphere (0045-6535) (Elsevier BV), 2019-04 , Vol. 221 , P. 278-291
DOI 10.1016/j.chemosphere.2019.01.035
WOS© Times Cited 3
Keyword(s) Microalgae, Microplates, Screening, Pesticides, Toxicity, Exposure characterisation
Abstract

Pesticides used in viticulture create a potential risk for the aquatic environment due to drift during application, runoff and soil leaching. The toxicity of sixteen pesticides and one metabolite were evaluated on the growth of two marine microalgae, Tisochrysis lutea and Skeletonema marinoi, in 96-h exposure assays conducted in microplates. For each substance, concentrations of stock solutions were analytically measured and abiotic assays were performed to evaluate the chemical stability of pesticides in microplates. For two chemicals, microalgae exposures were run simultaneously in microplates and culture flasks to compare EC50 calculated from the two exposure systems. Results from chemical analyses demonstrated the low stability of hydrophobic pesticides (log KOW > 3). For such chemicals, EC50 values calculated using measured pesticide concentrations were two-fold lower than those first estimated using nominal concentrations. Photosystem II inhibitors were the most toxic herbicides, with EC50 values below 10 μg L−1 for diuron and around double this for isoproturon. Chlorpyrifos-methyl was the only insecticide to significantly affect the growth of T. lutea, with an EC50 around 400 μg L−1. All fungicides tested were significantly toxic to both species: strobilurins showed low overall toxicity, with EC50 values around 400 μg L−1, whereas quinoxyfen, and spiroxamine, showed high toxicity to both species, especially to T. lutea, with an EC50 below 1 μg L−1 measured for spiroxamine in culture flasks. This study highlights the need to perform chemical analyses for reliable toxicity assessment and discusses the advantages and disadvantages of using microplates as a toxicity screening tool.

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Dupraz Valentin, Stachowski-Haberkorn Sabine, Wicquart Jérémy, Tapie Nathalie, Budzinski Hélène, Akcha Farida (2019). Demonstrating the need for chemical exposure characterisation in a microplate test system: Toxicity screening of sixteen pesticides on two marine microalgae. Chemosphere, 221, 278-291. Publisher's official version : https://doi.org/10.1016/j.chemosphere.2019.01.035 , Open Access version : https://archimer.ifremer.fr/doc/00474/58558/