To better understand the potential ecotoxicological impacts of silver nanoparticles (AgNPs) and silver nanowires (AgNWs) released into freshwater environments, the toxicities of these nanomaterials were assessed and compared using standard OECD guidelines including “Daphnia sp., Acute Immobilisation Test”, “Fish, Acute Toxicity Test”, and “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”. According to estimated median lethal/effective concentrations of AgNWs/ NPs in the present study, the order of animal susceptibility was: Daphnia magna > Raphidocelis subcapitata > Oryzias latipes. Thus, both AgNPs and AgNWs tested in the current study should be classified according to GHS (Globally Harmonized System of Classification and Labelling of Chemicals) as “category acute 1” for D. magna, and “category acute 2” for O. latipes and R. subcapitata. The results showed that AgNPs were more toxic when compared with AgNWs. The change in toxicity could be because of the different degree of Ag+ dissolution due to differences in surface area between the sphere shape of AgNPs and the rod shape of AgNWs. In general, our results suggest that the release of silver nanomaterials into the freshwater aquatic environment should be carefully considered
