Bioaccumulation and in vivo formation of titanium dioxide nanoparticles in edible mussels

The aim of this study was to evaluate the bioaccumulation of titanium dioxide nanoparticles (TiO(2)NPs) in edible mussels bred in polluted artificial seawater. An in vivo study was conducted by exposing mussels to different concentrations of TiO(2)NPs (0.25 mg/L and 2.5 mg/L) or ionic titanium (1.6 mg/L) for 4 days. Inductively coupled plasma mass spectrometry (ICP-MS) showed titanium presence in all groups proportional to exposure levels (concentration range: 209-1119 mu g/kg). Single particle ICP-MS revealed NPs in both TiO2NP treated mussels (concentration range: 231-1778 mu g/kg) and in ionic titanium treated mussels (concentration 1574 mu g/kg), suggesting potential nanoparticle formation in vivo. These results were confirmed by transmission electron microscopy with energy dispersive X-ray detection. Nonetheless, mussels eliminated more than 70% of the TiO(2)NPs after 3 days' depuration. These results show the potential for consumer exposure to TiO(2)NPs when contaminated mussels are consumed without a proper depuration process.