Bioaccumulation and effects of sediment-associated gold- and graphene oxide nanoparticles on Tubifex tubifex

With the development of nanotechnology, gold (Au) and graphene oxide (GO) nanoparticles have been widely used in various fields, resulting in an increased release of these particles into the environment. The released nanoparticles may eventually accumulate in sediment, causing possible ecotoxicological effects to benthic invertebrates. However, the impact of Au-NPs and GO-NPs on the cosmopolitan oligochaete, Tubifex tubifex, in sediment exposure is not known. Mortality, behavioral impact (GO-NP and Au-NP) and uptake (only Au-NP) of sediment-associated Au-NPs (4.9 ± 0.14 nm) and GO-NPs (116 ± 0.05 nm) to T. tubifex were assessed in a number of 5-day exposure experiments. The results showed that the applied Au-NP concentrations (10 and 60 μg Au/g dry weight sediment) had no adverse effect on T. tubifex survival, while Au bioaccumulation increased with exposure concentration. In the case of GO-NPs, no mortality of T. tubifex was observed at a concentration range of 20 and 180 μg GO/g dry weight sediment, whereas burrowing activity was significantly reduced at 20 and 180 μg GO/g dry weight sediment. Our results suggest that Au-NPs at 60 μg Au/g or GO-NPs at 20 and 180 μg GO/g were detected by T. tubifex as toxicants during short-term exposures.