PFASs in Finnish rivers and fish and the loading of PFASs to the Baltic Sea

The concentrations of per- and polyfluoroalkyl substances (PFASs) in the Finnish aquatic environment were measured in riverine waters and in inland, coastal and open sea fish. In addition, the PFAS load to the Baltic Sea from 11 rivers was calculated. Measurements show that PFASs, including restricted perfluorooctane sulfonic acid (PFOS), are widely present in the Finnish aquatic environment. At three out of 45 sampling sites, the concentration of PFOS in fish exceeded the environmental quality standard (EQS) of the Water Framework Directive (WFD). The annual average (AA) ∑23PFAS concentration in surface waters ranged from 1.8 to 42 ng L−1 and the concentration of PFOS exceeded the AA-EQS in three out of 13 water bodies. In European perch (Perca fluviatilis) and Baltic herring (Clupea harengus membras), the ∑PFAS concentration ranged from 0.98 to 1 µg kg−1 f.w. (fresh weight) and from 0.2 to 2.4 µg kg−1 f.w., respectively. The highest concentrations in both surface water and fish were found in waters of southern Finland. The riverine export of ∑10PFAS to the Baltic Sea from individual rivers ranged from 0.4 kg yr−1 to 18 kg yr−1. PFAS concentrations in fish of point-source-polluted sites and coastal sites were higher compared to fish of open sea or diffusely polluted sites. The PFAS profiles in surface waters of background sites were different from other sites. This study shows that PFASs are widely found in the Finnish aquatic environment. Different PFAS profiles in samples from background areas and densely populated areas indicate diverse sources of PFASs. Although atmospheric deposition has a substantial influence on PFAS occurrence in remote areas, it is not the dominant source of all PFASs to the aquatic environment of Finland. Rather, wastewaters and presumably contaminated land areas are major sources of PFASs to this aquatic environment.