Trace Metal Accumulation in Atlantic Bluefin Tuna and Correlations with Protein-Lipid Composition

This study determines the biochemical composition and metal concentrations (Hg, Fe, Zn, Cu) in muscle tissue of reared Atlantic bluefin tuna and investigates whether protein-lipid composition affects metal accumulation. A significant positive relationship was found between Hg concentrations and protein content, whereas a strong negative relationship between Hg concentrations and lipid content was revealed. Opposite results were obtained, correlating Zn concentrations with biochemical components. No correlations between the concentrations of the other two metals and the protein or lipid components were observed. Evidently, biochemical components may influence the accumulation of certain metals, but not in the same way. Although the analyzed tuna samples represent a rich source of essential metals, Hg may pose a risk to consumers. Our results suggest that a lower level of Hg can be associated with greater lipid and lower protein content. Consumers could reduce the health risk from Hg by choosing constantly high-fat bluefin tuna.