Distribution of perfluoroalkyl acids in fish species from the Baltic Sea and freshwaters in Finland

Highlights • Fish caught in the Baltic Sea and Finland's freshwaters were analysed for 13 PFAAs. • ∑PFAA concentrations were highest in the Baltic smelt. • PFOS was most frequently detected PFAA in fish from freshwaters and the Baltic Sea. • PFOS concentration in all species except in smelt was below the EQSbiota. • TWI derived by EFSA for ∑PFAS-4 was exceeded in 10 of 13 Baltic fish species.

Occurrence and distribution of perfluoroalkyl acids (PFAAs), a sub-category of per- and polyfluoroalkyl substances (PFASs), is widespread in the environment. Food, especially fish meat, is a major pathway via which humans are exposed to PFAAs. As fish is an integral part of Nordic diet, therefore, in this study, several fish species, caught in selected Baltic Sea basins and freshwater bodies of Finland, were analysed for PFAAs. Perfluorooctane sulfonate (PFOS) was detected in all Baltic Sea fish samples and in >80% fish samples from freshwaters. PFOS contributed between 46 and 100% to the total PFAA concentration in Baltic Sea fish samples and between 19 and 28% in fish samples from freshwaters. Geographically, concentration ratios of PFOS to other PFAAs differed between fish from the Baltic Sea and Finnish lakes suggesting that distribution of PFAAs differ in these environments. Results were compared with current safety thresholds – environmental quality standard for biota (EQSbiota) set by the European Commission and a group tolerable weekly intake (TWI) for the sum of four PFASs (∑PFAS-4) i.e. perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS) and PFOS, recommended by the European Food Authority (EFSA). EQSbiota compliance was observed for PFOS in all species except smelt caught in the Baltic Sea and also in the River Aurajoki, where smelt had migrated from the Baltic Sea for spawning. Moderate consumption of most Baltic fishes (200 g week−1) results in an exceedance of the new TWI (4.4 ng kg−1 body weight week−1) for ∑PFAS-4.