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DOI 10.1897/05-032R1.1
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Title (Primary) Effects of the organophosphate paraoxon-methyl on survival and reproduction of Daphnia magna: importance of exposure duration and recovery
Author Duquesne, S.; Reynaldi, S.; Liess, M.
Source Titel Environmental Toxicology and Chemistry
Year 2006
Department OEKOTOX
Volume 25
Issue 5
Page From 1196
Page To 1199
Language englisch
Keywords exposure duration; insecticide; sublethal effect; recovery
Abstract The aim of this study was to determine the influence of exposure duration (1 h, 24 h, continuous) to paraoxon-methyl on the magnitude of lethal and sublethal effects, the shape of the concentration-response relationships and the recovery processes in Daphnia magna. Survival was more severely reduced in the continuous than in the pulse exposure regimes. The lethal concentrations (3d median lethal concentration [LC50] values) were 233, 2.33, and 1.14 mu g/L after 1-h, 24-h, and continuous exposure, respectively. The shapes of the concentration-response relationships for survival were significantly different after 1 h of exposure than after 24-h and continuous exposure. Indeed, the slopes of the curves defined by the ratios LC90/LC10 (ratio of 90 and 10% lethal concentrations) were 100, 1.74, and 1.97 for 1-h, 24-h, and continuous exposure, respectively. The large difference between 1 h and longer durations of exposure shows that the population is partially affected (10-90%) over a much broader range of concentrations when exposure is short. Negative effects on reproductive outputs occurred mostly at concentrations affecting partly the survival and therefore also over a broad range of concentrations after 1 h of exposure. However, these effects were only transient in the pulse exposure regimes as individual performances recovered. By contrast, reproductive outputs of survivors exposed continuously remained impaired. These results suggest that a refined risk assessment should consider exposure duration because it influences the magnitude of effects and recovery.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=2590
Duquesne, S., Reynaldi, S., Liess, M. (2006):
Effects of the organophosphate paraoxon-methyl on survival and reproduction of Daphnia magna: importance of exposure duration and recovery
Environ. Toxicol. Chem. 25 (5), 1196 - 1199 10.1897/05-032R1.1