Each xenobiotic experiment was initiated with 10 replicates, in each of which were 10 M. macrocopa in a 200 ml Erlenmeyer flask. During the experiments, although some replicates were lost, there was always a minimum of 8 replicates for each experiment; (thus the number of live cladocerans expected at each time point per experiment was 80, 90 or 100, assuming no mortalities). The flasks were kept in a temperature-controlled room at 20 ± 1 °C, and illuminated by cool white light in a 14:10 h light:dark rhythm. Every second day, the number of live and dead cladocerans was recorded, and the exposure medium was exchanged. Dead individuals were removed immediately after counting.