Ecotoxic Effects of the Vehicle Solvent Dimethyl Sulfoxide on Aquatic Model Organisms

Abstract Dimethyl sulfoxide (DMSO) is widely used as a vehicle solvent in ecotoxicity bioassays. However, despite its frequent use, itcould be toxic for organisms at some concentrations. Hence, the aim of this study was to investigate the effectsof DMSO on the population growth rate of the microalgaeRaphidocelis subcapitata, the mobility of the microcrustacean Daphnia magna,and the reproduction of the rotiferBrachionus calyciflorus. DMSO was applied to the organisms in concentrations ranging from 0.031–4%. For R. subcapitata significant effects in growth inhibitionafter 72 h of exposure was 0.125% DMSO,being the lowest observed effectconcentration (LOEC). The 50% effective concentration (EC50) was2.138 ± 0.372%. In D. magna,significant differences in the mobility after 24 h or 48 h of exposure was 1% DMSO being 1.712± 0.207% and 1.167± 0.220%DMSO the EC50 observed for 24 h and 48 h exposure, respectively. For B. calyciflorus,it was not possible to validate the tests performed, as there were insufficient animals alive in the control conditions at the end of the exposure period. Therefore, we recommended avoiding DMSO as a vehicle in assays using B. calyciflorus,and to use final DMSO concentrationsin experimental solution not exceeding 0.125% forR. subcapitata and 0.5% for D. magna.