1. Human toxicology—Concerns about the toxicology of PFCs have centered on their estrogenic properties and accumulation and persistence in humans. Human exposure to perfluoro compounds takes place through ingestion and inhalation. Since these compounds enter the food chain and water sources and are persistent, ingestion of contaminated food and water products is a major source of human accumulation. The human half-life of PFOA is estimated to be about 3 years. As a persistent chemical and an endocrine disrupter, it is likely that it has some long-term adverse impact on reproductive function, cellular proliferation, and other cellular homeostatic mechanisms. Several PFCs (but not perfluoro compounds derived from PFOA) have been found to act as proliferators of breast cancer cells. However, a large epidemiologic study recently demonstrated a statistically significant association between high and very high serum PFOA levels in workers and kidney cancer, and possibly prostate cancer, ovarian cancer, and non-Hodgkin’s lymphoma. There also may be modest associations with cholesterol elevation and uric acid abnormalities. Finally, an acute pulmonary disorder, polymer fume fever, is caused by the pyrolysis of PFOA. Like metal fume fever, seen in welders as a result of cadmium vaporization, polymer fume fever has an acute onset several hours after exposure to the vaporized PFOA and may cause severe respiratory distress. The onset of constitutional symptoms, malaise, chills and fever, and respiratory distress is characteristic of fume fevers. While polymer fume fever is usually mild and self-limited, noncardiogenic pulmonary edema has occurred. Whenever PFOA is heated above 350–400°C, toxic fumes capable of causing polymer fume fever are emitted. Overheated household cookware or burning of coated fabrics present this risk.
Other human effects are not clearly defined, although animal studies have shown toxic effects on immune, liver, and endocrine function, and some increase in tumors and neonatal deaths. A useful American Cancer Society fact sheet on the subject may be found at https://www.cancer.org/cancer/cancer-causes/teflon-andperfluorooctanoic-acid-pfoa.html.
2. Environmental toxicology—Perfluoro compounds are persistent environmental chemicals having a broad environmental impact. PFOA and related compounds are now found widely in water, soil, and many terrestrial and avian species. Aquatic organisms have accumulated significant loads of PFCs. An extensive risk assessment of the perfluoro chemicals has been carried out by Environment Canada, and guidelines have been developed for the management of PFOA and related compounds. These may be found at http://www.ec.gc.ca/ese-ees/default. asp?lang=En&n=451C95ED-1.