Toxicity of silver nanoparticles on the clam Ruditapes decussatus assessed through biomarkers and clearance rate∗

Abstract

The current bioassay aims the evaluation of the ecotoxicity of the silver nanoparticles (NPs) (100 and 200 μg l-1) on Ruditapes decussatus after 48 h and 7 days of its exposure. The biochemical analyses performed at gills and digestive glands showed a disturbance of the antioxidant system following the exposure of clams to Ag NPs. The catalase activity was induced and varied significantly depending on the concentration of Ag NPs and the exposure time, as well as the organ analysed. Simultaneousely, a decrease in Gluthation S-Transferase activity was observed at all concentrations tested and organs considered. The acetylcholinesterase activity results confirmed that the threshold of Ag NPs able to disrupt the the cholinergic system was less than 100 μg l-1. In overall, silver nanoparticles had a significant caused antagonistic effect on clams in both oxidative- and cholinergic states. Furthermore the findings obtained in this study demonstrated that Ruditapes decussatus can employed as a potential bioindicative species in the assessment of the toxicity of such an emerging material as Ag NPs.