In recent years, awareness of pollution and climate change has spread around the world. Terms like personal carbon footprints and microplastics have established themselves in our society. Yet, I have only recently learned of another type of pollutant that has been affecting populations worldwide for decades: per- and polyfluoroalkyl substances.
Per- and polyfluoroalkyl substances (or PFASs) is an umbrella term for over 4000 different substances. These synthetic substances are all characterized by the presence of linked carbon and fluorine atoms. Production of these chemicals started in the 1940s when scientists discovered that their strong carbon-fluorine bonds could repel grease, oil, heat and water. Nowadays, they are used in a variety of products, including:
- Non-stick cookware (ex. Teflon)
- Stain-resistant fabrics and carpeting
- Waterproof clothing (ex. Used to waterproof boots – Scotchgard, Gore-tex)
- Firefighting foams (ex. used near airbases or airports)
- Personal care products, like shampoo
- Microwave popcorn bags
With their wide range of applications, they have lead to many improvements in quality of life and safety, so where is the problem?
One of the main problems with PFASs is their lifetime. Their strong carbon-fluorine bonds repel water, oil, and heat but also make them impervious to natural decay. In fact, their resistance to break down has made half-life is so long, scientists can not even estimate it. This has lead to PFASs being found all over the globe, from Free-Ranging Bottlenose Dolphins in the Gulf of Mexico to the blood and plasma of residents of arctic Russia and Uzbekistan.
As we cook with nonstick cookware, eat our favourite microwave popcorn in small amounts, or affected wildlife, such as fish, small amounts of PFAS ender our bodies. However, this is just one of the many ways we ingest these chemicals. The main way of ingestion is drinking contaminated water. According to a Canada Health survey done in 2017, 98.5% of Canadians have PHASs in their bloodstream due to how widespread it is in our environment.
The sheer strength of the carbon-fluorine bonds was the reason that many did not think that they could react with living tissue. However, we know know that this is inaccurate.
Suspicion of the adverse health effects caused by PFAS began in 1998 by Wilbur Tennet, a cattle farmer downstream from and bordered a landfill used by the DuPont Washington Works, a company that was using PFASs, more specifically Perfluorooctanoic acid (PFOA). He noticed that the cattle that drank the river water suffered from malformations, tumours, black teeth, hair loss and even death. The resulting joint lawsuit with him and the bordering town for the water contamination caused global recognition of the issue.
Afterwards, numerous studies looked into the two most common PFAS used at the time: perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PHOA). They found that the two PHASs caused a plethora of problems including reproductive and developmental, liver and kidney, and immunological effects and tumours in laboratory animals as well as increased cholesterol, lowered infant birth weights, effects on the immune system, cancer (for PFOA), and thyroid hormone disruption (for PFOS). Due to this, industries voluntarily phased out PFOS and PHOA and replaced them with other PFASs. Additionally, PHOS has been globally restricted since 2009, and PHOA has been globally eliminated since 2019.
Though Health Canada Health Canada maintains that PFOS and PFOA are not a concern for human health at current levels of exposure. Ways of reduction include avoiding non-stick cookware, looking for PFOS-free labels in textiles and avoiding cosmetic products containing “fluoro” in their name. However, we have national guidelines on 11 different PFASs in our drinking water, so I don’t see it as much of a health concern. Personally, for me, the bigger issue here (besides the long term environmental effects) is the accessibility of chemicals into Canadian products. For nearly 60 years PFASs remain completely unrestricted. In fact, the PFASs that succeeded PFOS and PFOA still lack full toxicology data and remain unregulated.