Graphene oxide in the marine environment: Toxicity to Artemia salina with and without the presence of Phe and Cd2

Abstract

Given the increasing potential of graphene oxide entering marine environments, it is imperative to assess the risks of GO on marine ecosystem, including its direct toxicity to marine organisms and indirect toxicity brought by co-existing aquatic pollutants, as a result of the remarkable adsorption capacity of GO. In the present study, the acute toxicity of GO, Phe, Cd²⁺, GO-Phe, and GO-Cd²⁺ to Artemia salina were systemically assessed and compared for the first time. Although the lethal effects of GO alone to A. salina only appeared at high GO dose (500 mg/L), its sublethal toxicity (growth inhibition) at concentrations as low as 1 mg/L was observed by microscopy, which was likely closely related to the GO-induced oxidative stress in A. salina. Compared with the toxicity of Phe alone, GO-Phe exhibited a synergistic effect to A. salina at a high GO concentration. For GO-Cd²⁺, the toxicity was positively correlated with both GO dose and Cd²⁺ dose. The increased toxicity of GO-Phe or GO-Cd²⁺ at high doses might be attributed to the promoted bioaccumulation of toxicants by GO, as the adhesion of GO complexes to intestinal tract of A. salina was observed during the toxicity tests, which probably resulted in further toxicological effects.

Keywords: Acute toxicity; Artemia salina; Cd(2+); Graphene oxide; Phe.