title: Influence of duration of exposure to the pyrethroid fenvalerate on sublethal responses and recovery of Daphnia magna straus.
abstract: This study compares lethal and sublethal responses of Daphnia magna Straus exposed to fenvalerate continuously (21 d) and as a pulse (24 h). Survival was reduced more severely in the continuous- than in the pulse-exposure regime. Complete mortality occurred at 1 microg/L for continuous exposure and at 3.2 microg/L for pulse exposure. Regarding reproductive endpoints, fenvalerate delayed the age at first reproduction. At the beginning of the reproductive phase (day 10), this delay resulted in a reduction of the neonates per living female at similar concentrations in both exposure regimes (0.3 and 0.1 microg/L for continuous and pulse exposure, respectively). The population growth rate was inhibited in continuous and pulse exposure at 0.3 and 0.6 microg/L, respectively. However, the effects of fenvalerate in the pulse exposure were transient. After 21 d, a recovery to values close to the controls occurred with respect to the total neonates per female and the population growth rate over a broad range of concentrations from 0.1 up to 1 microg/L. In contrast, no substantial recovery occurred in the continuous-exposure regime.
authors.affiliation: Department of Chemical Ecotoxicology, UFZ Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, Germany. sebastian.reynaldi@ufz.de
authors.forename: Sebastián
authors.initials: S
authors.lastname: Reynaldi
authors.forename: Matthias
authors.initials: M
authors.lastname: Liess
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D009570:Nitriles / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C017690:fenvalerate