PFAS exposure of juvenile loggerhead turtles (Caretta caretta) from the Western Mediterranean Sea to 36 PFAS and its association with oxidative stress.

The concentrations of 36 per- and polyfluoroalkyl substances (PFAS) and two oxidative stress biomarkers, dityrosine (DIY) and 8-Hydroxy-2'-deoxyguanosine (8-OHdG), were determined with UPLC-MS/MS in the liver, kidney, muscle, and fat tissue of loggerhead turtles from the western Mediterranean Sea. 8-OHdG was highly prevalent in the liver, with a detection rate (DR) of 95.5%, demonstrating its potential as a biomarker of oxidative stress, it cannot be linked specifically to PFAS. Dityrosine, however, was not often determined in these marine turtles' tissues (DR = 17%). Short chain PFAS, like 6:2 FTS, PFPeA and NaDoNa were very prevalent (DRs > 50%); although PFOS was found in 76.5% of the kidneys and 41.2% of the muscle samples of the turtles studied. Interestingly, ∑13PFCAs showed high concentrations both in kidney and in liver (median = 3347.27 ng/g d.w. and 816.84 ng/g d.w., respectively). PFAS with similar chemical structures accumulated in the same organs, potentially indicating similarities in their metabolism. Exposure to these PFAS is expected to be relatively recent, as most turtles in this study were juveniles. Finally, no correlations were observed between PFAS concentrations and sex, size classes or location (provinces), therefore, no patterns in bioaccumulation could be assessed. Our findings suggest that these turtles experience chronic PFAS exposure, with some individuals accumulating high concentrations of certain compounds.