Rising trend of production and use of nanoparticles has increased the possibility of their release into the aquatic environments. Therefore, knowing toxic effects of these materials on aquatic organisms is of great importance. The objective of this research was to study the acute toxicity of colloidal silver nanoparticles (CAgNPs) through determining the lethal concentrations in the euryhaline teleost, Aphanius dispar. Toxicology experiments were conducted for 96 h in freshwater according to the OCED 203 standard protocol. Fish mortality was recorded every 24 h after exposure to different concentrations of CAgNPs and then the data were analyzed using the US EPA Probit analysis program. Based on the results, the estimated 96h LC50 of CAgNPs was 59.876 mg/L. Accordingly, the tested CAgNPs should be classified according to GHS (Globally Harmonized System of Classification and Labelling of Chemicals) as “category acute 3” for Aphanius dispar; this means that presence of CAgNPs in the environment of this fish is detrimental and therefore its release into the aquatic ecosystem should be carefully considered.
