Dietary exposure of zinc oxide nanoparticles (ZnO-NPs) from canned seafood by single particle ICP-MS: Balancing of risks and benefits for human health

The present study aims to give information regarding the quantification of ZnO-NPs in canned seafood, which may be intentionally or unintentionally added, and to provide a first esteem of dietary exposure. Samples were subjected to an alkaline digestion and assessment of ZnO-NPs was performed by the single particle ICP-MS technique. ZnO-NPs were found with concentrations range from 0.003 to 0.010 mg/kg and a size mean range from 61.3 and 78.6 nm. It was not observed a clear bioaccumulation trend according to trophic level and size of seafood species, although the mollusk species has slightly higher concentrations and larger size. The number of ZnO-NPs/g does not differ significantly among food samples, observing an average range of 5.51 × 106 - 9.97 × 106. Dissolved Zn determined with spICP-MS revealed comparable concentration to total Zn determined with ICP-MS in standard mode, confirming the efficiency of alkaline digestion on the extraction of the Zn. The same accumulation trend found for ZnO-NPs was observed more clearly for dissolved Zn. The ZnO-NPs intake derived from a meal does not differ significantly among seafood products and it ranges from 0.010 to 0.031 µg/kg b.w. in adult, and from 0.022 to 0.067 µg/kg b.w. in child. Conversely, the intake of dissolved Zn is significantly higher if it is assumed a meal of mollusks versus the fish products, with values of 109.3 µg/kg b.w. for adult and 240.1 µg/kg b.w. for child. Our findings revealed that ZnO-NPs have the potential to bioaccumulate in marine organisms, and seafood could be an important uptake route of ZnO-NPs. These results could be a first important step to understand the ZnO-NPs human dietary exposure, but the characterization and quantification of ZnO-NPs is necessary for a large number of food items