Bioaccumulation of legacy and emerging contaminants in tuna species

Environmental contamination of legacy contaminants has been of great concern worldwide because of their persistence and toxicity to humans and marine species. Only in the last decade, the presence and accumulation of emerging contaminants, and, consequently, their adverse effects in marine biota have been considered. The present research was performed to compare the different distribution of legacy contaminants (Pesticides, PCBs and PAHs) and emerging contaminants (UV filters and Fragrances) in the liver and muscle tissues of three tuna species living in different locations and with different behaviour and feed habits: Sarda sarda, Katsuwonus pelamis from the Atlantic Ocean (Gulf of Càdiz) and Thunnus thynnus from the Strait of Gibraltar. The extraction and quantitative determination of these contaminants from liver and muscle samples have been carried out by Accelerate Solvent Extraction and GC-MS/MS techniques, respectively. From the statistical analysis, significant differences have been found for Fragrances, Pesticides, PCBs and PAHs both among the three tuna species and between the two tissues. Post-hoc analysis showed significant differences between the three tuna species and the tissues, revealing that K. pelamis species differs significantly from the other two species, both in liver and muscle, and that legacy contaminants are responsible for significant differences between and within species. We also explored the similarities between concentrations of PCBs and DDTs in liver and muscle tissue found in samples of T. thynnus and K. pelamis in this study, compared to concentrations of PCBs and DDTs found in specimens of tuna collected in different geographical areas. As a result of the continuous exposure of the marine top predators, such as tuna species, to variable concentrations of emerging and legacy contaminants, their concentration in the marine environment must be constantly monitored.