AbstractThe spatial distribution of 15 polyfluoroalkyl compounds (PFCs) in surface water was investigated in the North Sea, Baltic Sea and Norwegian Sea. In addition, an interlaboratory comparison of the sampling techniques and analysis was conducted. Highest concentration in the North Sea was found near the coast, whereas the ∑PFC concentration decreased rapidly from 18.4 to 0.07 ng l−1 towards the open North Sea. The river Elbe could identify as a local input source for PFCs into the North Sea, whereas perfluorobutanoic acid (PFBA) was transported into the sampling area with the easterly current. In contrast to the North Sea, the distribution of PFCs in the Baltic Sea was relatively homogenous, where diffuse sources dominated. In general, the composition profile was influenced from local sources caused by human activities, whereas atmospheric depositions of here analysed PFCs were negligible, but it could have possibly an influence on low contaminated sites like the open North Sea or Norwegian Sea.