2. Material and methodsMesotrione (CAS 104206-82-8) concentrations were obtainedfrom a stock solution prepared in distilled water at 136.40 mg L−1.Fish were exposed to mesotrione in the nominate concen-trations of 1.8, 7, 30, 115, and 460 g L−1. The concentration of1.8 g L−1is an ecologically relevant concentration, since this valueis found in runoff in crop fields [5]. The other concentrations weredetermined as a fourfold of the previous concentration.