Comparative evaluation on the toxic effect of silver (Ag) and zinc oxide (ZnO) nanoparticles on different trophic levels in aquatic ecosystems: A review

Abstract Silver (Ag) and zinc oxide (ZnO) are considered to be harmful nanoparticles (NPs) to the aquatic organisms as their intake causes toxic impacts to wildlife, through direct ingestion or by the transference along trophic levels. Over usage and ultimate disposal of metallic particles from the industries subsequently lead to pollution of the aquatic environment. Exposure of NPs in aquatic ecosystem alters biological and physicochemical parameters of the water and aquatic organisms and determines their potential ecotoxicological impacts. Prolonged exposure of aquatic organisms to these NPs results in differential bioaccumulation and distribution into internal organs like liver, kidney, gills, brain, and muscle tissue. The contact of NPs to aquatic organisms induces various types of toxic traits including cytotoxicity, genotoxicity, and epigeneticity. Taking this in consideration, this present review focuses on the comparative toxic impact of ZnO and Ag NPs towards both vertebrates and invertebrates in aquatic ecosystems.