There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release via wastewater discharges. In this study, the toxicities of sediment associated nano (<100nm)-, micron (2-3.5μm)- and ionic (AgNO 3)-Ag on the sediment-dwelling polychaete, Nereis diversicolor, were compared after 10 days of sediment exposure, using survival, DNA damage (comet assay) and bioaccumulation as endpoints. The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25, and 50μgAg/g dry weight (dw) sediment. Our results showed that Ag was able to cause DNA damage in Nereis coelomocytes, and that this effect was both concentration- and Ag form-related. There was significantly greater genotoxicity (higher tail moment and tail DNA intensities) at 25 and 50μg/gdw in nano- and micron-Ag treatments and at 50μg/gdw in the ionic-Ag treatment compared to the controls (0μg/gdw). The nano-Ag treatment had the greatest genotoxic effect of the three tested Ag forms, and the ionic-Ag treatment was the least genotoxic. N. diversicolor did accumulate sediment-associated Ag from all three forms. Ag body burdens at the highest exposure concentration were 8.56±6.63, 6.92±5.86 and 9.86±4.94μg/gdw for worms in nano-, micron- and ionic-Ag treatments, respectively, but there was no significant difference in Ag bioaccumulation among the three treatments.
Bibliographical noteFunding Information:
This work was supported by Roskilde University (RUC) and is done in cooperation with the EU NanoReTox project (7th Framework Programme, Grant Agreement no. CP-FP 214478-2). The authors gratefully acknowledge Anne-Grete Winding, Klara Jensen, Anja Holden Damsholt, Anne Busk Faarborg and Rikke Guttesen for their technical guidance and assistance during experiments. Support from the China Scholarship Council (CSC) is also gratefully acknowledged.
- Ag body burden
- Marine invertebrate
- Sediment exposure
- Silver nanoparticles