Per- and polyfluoroalkyl substances (PFAS) have been produced and used since the 1950s. The chemical structure of PFAS makes the substances both lipophilic and hydrophilic. These properties have contributed to the use of PFAS in a number of industrial and commercial applications. Wastewater treatment plants are a collection point for contaminated water, and currently, there are no methods to completely purify the water from PFAS. Therefore, wastewater treatment plants constitute a direct source of PFAS emissions into the environment. The purpose of this study was to investigate the occurrence and concentration of perfluorosulfonates (PFSA), perfluorocarboxylates (PFCA), and their precursors. This was done by sampling sediment, water, and the organisms Monoporeia affinis, Macoma balthica, and Mytilus edulis in close proximity to the wastewater treatment plants Himmerfjärdsverket and Przedsiębiorstwo Wodociągów, both of which have their outlets in the Baltic Sea. The results of the study showed significant correlations between the concentrations of PFCA in sediment and PFSA in M. balthica with the distance to the wastewater treatment plant Himmerfjärden. No further significant correlations were found, indicating that the persistence, spread potential, and presence of diffuse sources of PFAS affect the concentrations in environmental matrices and organisms. The results also showed a very high concentration of PFAS in M. affinis, which differed from the other organisms. To put the results in a larger context, the study discussed how PFAS can spread from primary consumers to the remaining parts of the food web.