Potential toxic elements (PTEs) in wild and farmed Atlantic bluefin tuna (Thunnus thynnus) from Mediterranean Sea: Risks and benefits for human consumption

Abstract

Being on the top of the food chain, tunas are subjected to significative phenomena of bioaccumulation of conservative contaminants such as Potential Toxic Elements (PTEs). In this study, Cd, Pb and Fe levels in muscle of Mediterranean bluefin tuna (Thunnus thynnus) were determined by atomic absorption spectroscopy (GFAAS), both in wild and farmed groups, to investigate the safety and the quality of this fish as seafood. A total of 68 samples were collected, wild samples (n = 30) from Sardinia island (Italy) and farmed samples (n = 38) from an aquaculture fish farm in Malta. Mean values, expressed as mg kg−1 wet weight, were found as 0.014 (wild) and 0.02 (farmed) for Cd; 0.11 (wild) and 0.03 (farmed) for Pb and 13 (wild) and 7 (farmed) for Fe. Relationships between metal concentrations and biometric parameters were evaluated and a comparison between the levels of metals of wild and farmed groups has also been conducted. No statistically significant difference between the two groups was found for Cd, with 99% of samples below the EU limit. The difference for Pb levels were statistically significant, with wild samples showing concentrations more than four times higher than the farmed ones, but with 98% of samples below the EU limit. The levels of Fe were significantly lower in the farmed group with respect to wild specimens, although samples of both groups could be considered good products for the intake of this element. On the base of the recommended tolerable weekly intakes, samples of this study can be considered a safe seafood.