FN Archimer Export Format PT J TI Comparative embryotoxicity and genotoxicity of the herbicide diuron and its metabolites in early life stages of Crassostrea gigas: implication of reactive oxygen species production BT AF BEHRENS, Daphne ROUXEL, Julien BURGEOT, Thierry AKCHA, Farida AS 1:1;2:1;3:1;4:1; FF 1:PDG-RBE-BE-LBEX;2:PDG-RBE-BE-LBEX;3:PDG-RBE-BE;4:PDG-RBE-BE-LBEX; C1 IFREMER, Lab Ecotoxicol, Rue Ile dYeu,BP21105, F-44311 Nantes, France. C2 IFREMER, FRANCE SI NANTES SE PDG-RBE-BE-LBEX PDG-RBE-BE IN WOS Ifremer jusqu'en 2018 IF 4.129 TC 34 UR https://archimer.ifremer.fr/doc/00324/43521/43053.pdf LA English DT Article DE ;Oyster;Herbicide;Embryotoxicity;Genotoxicity;Oxidative stress;Biotransformation AB Herbicides are one of the major classes of pollutants contaminating coastal waters over the world. Among them, diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a phenylurea herbicide frequently detected in oyster-producing area, known to be toxic for this important exploited non-target species. With the aim to investigate the mechanisms by which diuron displays its toxicity in oyster, the implication of both biotransformation and oxygen reactive species (ROS) production was studied considering embryotoxicity and genotoxicity as endpoints. Comparative embryotoxicity and genotoxicity of diuron and its main metabolites (DCPMU, DCPU and 3,4-DCA) were thus studied on oyster larvae by the embryo-larval bioassay on D larvae and the comet assay on trochophore larvae, respectively. Exposures were also performed in presence and absence of known ROS scavenger compounds − ascorbic acid and N-acetylcysteine, to evaluate the involvement of oxyradicals in the toxic responses. In the case of diuron, the production of ROS on exposed oyster larvae was also measured using 2',7'-dichlorodihydrofluorescein diacetate as a probe for flow cytometric analysis. The results we obtained showed the embryotoxicity and genotoxicity of diuron and its metabolites in early life stages of the Pacific oyster. For concentrations ranging from 0.05 to 0.5 μg.L−1, diuron appeared significantly more embryotoxic than DCPMU and DCPU (p < 0.001). Embryotoxicity decreased with diuron metabolism as follows: diuron ≥ DCPMU = DCPU, highlighting that biotransformation can constitute a true detoxication pathways in oyster larvae by decreasing the toxicity of the parent compound. In the opposite, no difference was observed between diuron and its metabolites concerning larval development when considering a lower and more environmentally realistic range of concentrations (0.002 to 0.050 μg.L−1). 3,4-DCA was the only compound that did not show any sign of embryotoxicity, even at concentrations up to 5 μg.L−1. Concerning genotoxicity, no significant difference was observed between diuron and all of its metabolites including 3, 4 DCA with damages detected from the concentration of 0.05 μg.L−1. As for diuron, the toxicity of the metabolites seems to be mediated in some part by ROS production as clearly demonstrated by the decrease in genotoxicity and developmental abnormalities in the presence of the oxidant scavenger, ascorbic acid. PY 2016 PD JUL SO Aquatic Toxicology SN 0166-445X PU Elsevier Science Bv VL 175 UT 000376797700026 BP 249 EP 259 DI 10.1016/j.aquatox.2016.04.003 ID 43521 ER EF