Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are fluorinated hydrocarbons used as water-, oil-, and stain-resistant coatings in fabrics, leather, and carpets, and oil-resistant coatings for paper products for food contact, and also as photographic emulsifier, aviation hydraulic fluids, and fire-fighting foams. They are not reactive and are not easily degraded, making them persistent and present in the environment and in humans, where they can be transferred from the mother to the offspring during gestation and lactation. PFOS and PFOA induce reproductive and developmental toxic effects in different species and organs. The most studied mechanisms of action are peroxisome proliferator-activator receptors, thyroid hormone system, fatty acid homeostasis, and cell communication.
In humans, PFOS and PFOA induce reproductive and developmental effects such as changed birth variables, delayed development, and decreased fecundity of both men and women. Animal studies have revealed that exposure to PFOS and PFOA, during the gestational and/or the neonatal period, induces effects mainly on the developing lungs and different effects on the developing nervous system, such as changes in important proteins, delayed development, and impaired behavior, learning, and memory in the adult individual.
These findings have led to regulation of PFOS and PFOA in both Europe and the United States and these compounds have been proposed and/or considered as persistent organic pollutants in the United Nations and other international environmental conventions. Even so, more toxicological research is needed, especially concerning interactions with other pollutants, to gain better knowledge about the effects of PFOS and PFOA and to perform high-quality risk assessments and legislation.
