Bioaccumulation of silver nanoparticles in marine copepod Tigriopus japonicus under waterborne and dietary exposure

Abstract

At present, the emission of silver nanoparticles (AgNPs) will affect a variety of aquatic organisms. AgNPs may be transferred to the food web through the bioaccumulation or biomagnification of the food chain, which is harmful to at higher trophic level organisms, and even threatens human health. Therefore, in this study, we tested the acute toxicity effect of AgNPs to marine copepod Tigriopus japonicus, and analyzed the Ag bioaccumulation in T. japonicus under short-term waterborne (exposure of AgNPs to T. japonicus) and dietary exposure (AgNP-accumulated algae cells of Isochrysis galbana are used to feed T. japonicus). The results showed that, after 48 h exposure, significant effects of AgNPs on the mortalities were observed (LC50=6.330 mg·L−1). The bioaccumulation of Ag by T. japonicus under different exposure modes was positively correlated with exposure concentration and time, and the bioaccumulation level under waterborne exposure was significantly higher. The biomagnification of T. japonicus was not observed under 24 h dietary exposure of different AgNP concentrations (BMFs<1), but the transfer efficiency was higher under low exposure concentration (BMFlow concentration>BMFhigh concentration). This study is helpful to understand the toxicity mechanism and effect of AgNPs on aquatic organisms.