| Popis: |
The widespread use of pesticides in agriculture results in contamination of soil and water, and leads to adverse effects on non-target organisms. Cladocerans, especially daphnids, are an important component of aquatic ecosystems, linking primary producers to higher trophic levels. Due to their high sensitivity to toxicants, short life cycle and simple handling, they are commonly used model organisms in ecotoxicological research. So far, the effects of a wide range of pesticides on swimming activity of Daphnia species has been investigated. However, research on the effects of binary mixtures on behavioral endpoints of daphnids is very limited. The aim of this research was to assess the effects of binary mixtures of three triazole fungicides (tebuconazole, difenoconazole and fenbuconazole) on average swimming speed of Daphnia magna. D. magna neonates were hatched from ephippia by following the Daphtoxkit F instructions. Mixture experiments were conducted following a fixed-ratio ray design, by employing the equal effect concentration ratio approach. Mixtures of the chosen triazole fungicides were prepared based on EC50 values for average swimming speed after a 24-h exposure for single compounds. Single substances were mixed in ratios corresponding to five effect ratios, following the isobole method. No statistically significant differences from the additive effect were found in any of the mixtures tested. The results of this research indicate that movement parameters are sufficiently sensitive endpoints that can be used as a basis for designing experiments and proving the sublethal effects of binary mixtures on organisms. |
