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

Abstract

Titanium dioxide nanoparticles (TiO2NPs) 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 TiO2NPs in aquaculture mussels and turbot species. Mussels were exposed for 28 days, and turbot for 90 days, to different concentrations of citrate-coated TiO2NPs (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 TiO2NPs content and size distribution determination. In mussels TiO2NPs concentrations reached 2.28 × 10^8±5.84 × 10^7 NPs g^−1 after exposure to 1.0 mg L^−1 of 25 nm TiO2NPs for 28 days, and 4.79 × 10^8±2.36 × 10^8 NPs g^−1 for 1.0 mg L^−1 of 5 nm TiO2NPs 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 TiO2NPs. 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.