Perfluorooctanoic acid (PFOA) is a man-made fluorinated organic compound that belongs to the group of perfluorinated alkyl substances (PFAS). Due to its strong carbon-fluorine bonds, the chemical is very stable and degrades slowly both in the environment and in the human body resulting in bioaccumulation of the chemical. Furthermore, PFOA is characterized by water-, oil- and stain-repellent properties (US EPA, 2016a). PFOA is not readily excreted by humans and other primates (US EPA 2016b). According to several investigations, the half-life for elimination of PFOA is approximately two to four years (Li et al., 2018; Russell et al., 2015; Gomis et al., 2017; Worley et al., 2017; Brede et al., 2010).

Due to its properties, the chemical is used in a variety of ways, which can lead to human exposure. For example, PFOA was present in consumer products, such as stain- and water-repellent coatings on clothing, surfaces of cooking utensils (e.g., Teflon™), fire-fighting foam, cosmetic products as well as cleaning products (US EPA, 2016a). In addition to exposure via consumer products, PFOA can enter the body via other routes of transmission. For example, contaminated food, including meat and fish, can be a source of exposure (Trudel et al., 2008). PFOA can also be transferred to humans via house dust. Based on indoor dust samples collected from houses, apartments, offices, day care centers and cars, it was found that PFOA concentrations were highest in homes and offices (Björklund et al., 2009). In addition, PFOA can also be airborne. Particularly high PFOA air concentrations were detected in coastal regions. Chaemfa et al. (2010) explain this by the fact that PFOA in river discharges can easily rise into the air as vapor. In addition, elevated PFOA air concentrations were measured near a building construction, which could be explained by emissions of PFOA from building materials and furniture. Trudel et al. (2008), who determined the extent to which each exposure route contributes to exposure in North America and Europe, concluded that oral ingestion via food is the most important route of exposure to PFOA. Also drinking water is an important source of exposure to PFOA. Several studies have shown that drinking water contaminated by releases from PFOA manufacturing plants resulted in elevated PFOA blood concentrations in nearby residents (Hölzer et al., 2009; Fromme et al., 2017; Pitter et al., 2020).

Some effects on human health resulting from exposure to PFOA have been described. For example, a positive association between serum PFOA concentration and serum cholesterol levels has been found (Geiger et al., 2014; Li et al., 2020). In addition, it has been reported that higher PFOA concentrations can lead to thyroid disease (Melzer et al., 2010). In their study Wang et al. (2023) revealed that with increasing PFOA concentrations the risk of infertility in women increases. It is also discussed that PFOA exposure during pregnancy increases the risk of preterm birth (Gao et al., 2021). PFOA was classified as “possibly carcinogenic to humans” by the International Agency for Research on Cancer in 2017 (IARC, 2017). Since 2020, the production, use and import of PFOA, its salts and PFOA-related compounds is prohibited in the EU (European Commission, 2020).

An incident at an industrial plant in the Altötting district caused contamination of the environment with PFOA. Drinking water in particular was affected, whereupon a human biomonitoring study in 2018 found increased levels of PFOA in the blood of the population. Four years later, the population was tested again. The aim of this follow-up study was to investigate whether purification of the drinking water as the main PFOA exposure source has been successful in reducing internal PFOA exposure and to estimate the association of internal PFOA exposure with possible influencing factors, such as age, gender and consumption of fish and game meat.