Bioaccumulation patterns in aquaculture mussels and turbots exposed to different sizes of TiO2NPs

Titanium dioxide nanoparticles (TiO 2 NPs) are widely used in industry, leading to their presence in the marine environment where they can interact with and harm marine life. This study examines the impact and bioaccumulation of TiO 2 NPs in aquaculture mussels and turbot species. Mussels were exposed for 28 days, and turbot for 90 days, to different concentrations of citrate-coated TiO 2 NPs (25 and 5 nm). Inductively coupled plasma mass spectrometry (ICP-MS) and single-particle-ICP-MS (SP-ICP-MS) were used for Ti determination, and TiO 2 NPs content and size distribution determination. In mussels TiO 2 NPs concentrations reached 2.28 × 10 8 ±5.84 × 10 7 NPs g −1 after exposure to 1.0 mg L −1 of 25 nm TiO 2 NPs for 28 days, and 4.79 × 10 8 ±2.36 × 10 8 NPs g −1 for 1.0 mg L −1 of 5 nm TiO 2 NPs at 21 days, respectively. Bioaccumulation was also observed in mussel shells, which became fragile, with the highest Ti concentration reaching 12.4 ± 3.5 µg g −1 d.w. In turbot, the highest Ti concentration was found in the liver, reaching 1.6 ± 0.4 µg g −1 w.w. at 90 days to the highest dose of 5 nm TiO 2 NPs. Furthermore, turbots expelled Ti through the feces, reaching 41.0 ± 6.6 µg g −1 d.w. The results show the safety of turbot consumption and highlight the need for a correct depuration process of mussels before commercialization. • The dietary route was used in a chronic exposure study • TiO 2 NPs bioaccumulation in mussels increased with exposure time and dose. • Ti accumulation in mussel shells may be the reason for their weakening and breaking. • Ti was only accumulated in the liver of the turbot (non-edible part) • Turbot expelled most of Ti through the feces.