|
(19-09) Acute responses of Daphnia reared at different food levels to lindane. Antunes, Sara*,1, Castro, Bruno1, Gonçalves, Fernando1, 1 Dept. Biologia da Universidade de Aveiro, Campus de Santiago, Aveiro, Portugal ABSTRACT- Lindane is an organochlorine insecticide that has been recently banned in Portugal. In spite of this, it is still of widespread use in our country. Due to its agricultural use, large amounts of this persistent contaminant are leached onto surrounding lakes and groundwater. The toxic effects of this compound on the lenthic zooplanktonic communities could be strongly related to the population fitness, which is highly dependent on food availability. In order to test this hypothesis, acute responses of field-collected Daphnia longispina, reared at different food levels (scarce, normal, and high), were assessed in laboratorial exposures to several concentrations of lindane. Furthermore, the toxicological responses of D. longispina were compared to the response obtained with D. magna. The results suggest that food availability and lake trophic state may be important factors to take into account when assessing the toxic effects of lindane on the local zooplanktonic communities. The LC50s obtained for D. longispina and D. magna have shown that, under some circumstances, the latter may not be used as a representative species of the local zooplankton, in terms of contaminant sensitivity. Key words: Lindane, Daphnia longispina, Acute toxicity, Feeding conditions |
