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 (TiONPs) in edible mussels bred in polluted artificial seawater. An in vivo study was conducted by exposing mussels to different concentrations of TiONPs (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 µg/kg). Single particle ICP-MS revealed NPs in both TiONP treated mussels (concentration range: 231-1778 µg/kg) and in ionic titanium treated mussels (concentration 1574 µg/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 TiONPs after 3 days' depuration. These results show the potential for consumer exposure to TiONPs when contaminated mussels are consumed without a proper depuration process.