by Alana Coulombe, Education programs administrator

What are PFAS?

Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of over 4,700 human-made substances used in a wide range of consumer products (Health Canada, 2023). PFAS molecules consist of a chemically stable chain of linked carbon and fluorine atoms (National Institute of Environmental Health Sciences [NIEHS], 2024). This strong carbon-fluorine bond is responsible for most properties of PFAS including their inability to degrade easily in the environment (NIEHS, 2024). This is why PFAS have been dubbed “forever chemicals.”

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and long-chain perfluorocarboxylic acids (LC-PFCAs) are three commonly studied PFAS (Agency for Toxic Substances and Disease Registry [ATSDR], 2024). In Canada, PFOA, PFOS, and LC-PFCAs are currently included on the Toxic Substances List, giving the Canadian government the authority to adopt measures to prevent and control the use of these substances (King et al., 2024). Under the Prohibition Regulations, the Canadian government currently regulates the manufacture, use, sale, and import of PFOS, PFOA, and LC-PFCAs and products containing these substances (King et al., 2024).

Exposure to PFAS

Human exposure to PFAS is widespread but can vary by geography and occupation (NIEHS, 2024). For example, PFAS exposure may be higher for individuals in the aerospace, automotive, construction, and electronics industries (NIEHS, 2024). Humans are exposed to many different sources of PFAS including contaminated water or food, consumer products, industrial applications, and indoor and outdoor air (Health Canada, 2024). Products often containing PFAS include lubricants, cosmetics, surfactants, cleaning products, firefighting foams used to extinguish fuel fires, non-stick cookware, food packaging materials, stain-resistant textiles such as carpets, furniture, and clothing, as well as repellents for dirt, water, and grease (Health Canada, 2023). Although exposure can also occur by accidental ingestion of residue or dust from PFAS-containing products, current research suggests this is generally lower than exposures from PFAS-contaminated drinking water (ATSDR, 2024).

PFAS in Canada’s Drinking Water

Health Canada previously developed maximum acceptable concentration guidelines for PFOA (200 ng/L) and PFOS (600 ng/L) in drinking water and screening values for other PFAS (Public Health Ontario, 2023). However, some drinking water regulatory guidelines have recently been lowered by Health Canada with emerging evidence of potential health effects (Public Health Ontario, 2023). The proposed objective value of 30 ng/L for the sum of total PFAS detected in drinking water serves as an interim guideline while the revision of Health Canada’s drinking water guidelines for PFAS is underway (Public Health Ontario, 2023).

If you get your water from a public drinking water system, find out if PFAS are in your drinking water and if you are concerned, consider installing an in-home water treatment. If you get your water from a private drinking water well, be sure to conduct regular well testing and consider technologies designed to treat or remove contaminants.

Environmental Consequences

Over time, PFAS may leak into the soil, water, and air during production and use (ATSDR, 2024). Since PFAS do not break down easily, they remain in the environment for long periods of time and can bioaccumulate in the environment and our bodies (Health Canada, 2024). The extreme persistence of PFAS and the ability to migrate locally and over long distances in air or water has led to the presence of PFAS nearly everywhere in the environment (Health Canada, 2023). In fact, PFAS can be found in the air, soil, surface and groundwater, and oceans, as well as in wastewater, landfill leachate, sewage sludge, and contaminated sites worldwide (Health Canada, 2023). In Canada, PFAS contamination is even detectable in remote areas such as the Arctic (Health Canada, 2023).

PFAS in the environment can bioaccumulate in living organisms and have negative consequences on wildlife growth, reproduction, and development (Health Canada, 2023). While some PFAS can cause immune and nervous system toxicity, others have shown harmful effects on plants (Health Canada, 2023). Additionally, research shows that some PFAS can accumulate and become more concentrated as they move up the food chain in a process known as biomagnification, leading to higher exposures and enhancing adverse health effects (Health Canada, 2023).

Impacts on Human Health

Concerns about the public health impact of PFAS arise from its widespread use, numerous exposure sources, growing numbers, environmental persistence, and bioaccumulation (NIEHS, 2024). PFAS have been found in the blood of people and animals with repeated exposures across the world, although concentrations have generally decreased over time (ATSDR, 2024). Since humans and the environment are continuously exposed to multiple PFAS, this repeated cumulative exposure may increase the potential for adverse health effects (Health Canada, 2024). 

Although more research is needed to fully understand the direct health impacts of PFAS exposure, scientific studies demonstrate that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals. Many laboratory and epidemiological studies with PFAS report health effects on the liver, kidney, thyroid, immune system, and nervous system, as well as effects on metabolism, reproduction, and development (Health Canada, 2023). Specifically, associations exist between increased PFAS exposure and high cholesterol levels, low birth weight, pregnancy-induced hypertension and preeclampsia, and certain cancers (ATSDR, 2024).

With new PFAS continually being developed, PFAS pose a significant risk to the Canadian environment with adverse ecological and health effects observed. The risk associated with PFAS depends on exposure factors such as dose, frequency, route, and duration, as well as individual factors and other health determinants like access to safe water and quality healthcare (ATSDR, 2024). More research is needed to understand the many types of PFAS chemicals, the mechanisms of PFAS toxicity, and all potential sources of exposure (NIEHS, 2024).

Nature-based solutions

Preliminary findings reveal a potential role for plants in the remediation of PFAS-contaminated soils and groundwater. This technique, known as phytoremediation, utilizes certain plants to take up and store PFAS from the environment, affecting the transport and fate of PFAS in aquatic and terrestrial ecosystems (Adu et al., 2023). Similarly, wetlands offer a promising nature-based solution with environmental, economic, and societal benefits attributed to the potential combined effects of substrate removal, biodegradation, and phytoremediation processes (Savvidou et al., 2024). However, the accumulation of PFAS in plants poses a potential health threat to the animals and humans that consume the affected plants, and thus, more research is needed to determine best practices.

Emerging research suggests some fungi, bacteria, and enzymes show potential for PFAS degradation, however, further investigation is required (Grgas et al., 2023). For example, white-rot fungi (Phanerochaete chrysosporium) secrete natural enzymes that can degrade the chemical bonds in PFAS, offering a potential nature-based strategy for PFAS removal (Grgas et al., 2023).

What Can You Do to Limit Your Exposure?

Despite efforts to phase out PFAS, their persistence in the environment remains an ongoing problem. Although it is difficult to completely avoid PFAS, there are simple steps you can take to limit your exposure and protect your health and the environment.

• Avoid non-stick cookware and opt for stainless steel, cast iron, or ceramic cookware instead. If using non-stick cookware, avoid using steel wool cleaners which can scrape and release the PFAS coating into your food and the environment.
• Bring reusable containers to avoid single-use containers and grease-resistant packaging often coated with PFAS.
• Follow fish advisories to limit your consumption of fish from waterbodies contaminated with PFAS.
• Read labels and purchase PFAS-free cosmetics, varnishes, and household items when possible. 
• Avoid products such as PFAS-coated dental floss, fabrics with stain-resistant coatings, and microwave popcorn bags with PFAS coatings inside.

References

Adu, O., Ma, X., & Sharma, V. K. (2023). Bioavailability, phytotoxicity and plant uptake of per-and polyfluoroalkyl substances (PFAS): A review. Journal of Hazardous Materials, 447(130805). https://doi.org/10.1016/j.jhazmat.2023.130805

Agency for Toxic Substances and Disease Registry. (2024). What are the health effects of PFAS? U.S. Department of Health and Human Services. https://www.atsdr.cdc.gov/pfas/health-effects/overview.html

Grgas, D., Petrina, A., Štefanac, T., Bešlo, D., & Landeka Dragičević, T. (2023). A review: Per- and polyfluoroalkyl substances – biological degradation. Toxics, 11(5), 446. https://doi.org/10.3390/toxics11050446

Health Canada. (2023). Per- and polyfluoroalkyl substances (PFAS) – information sheet. Government of Canada. https://www.canada.ca/en/health-canada/services/chemical-substances/fact-sheets/chemicals-glance/per-polyfluoroalkyl-substances.html

Health Canada. (2024). Per- and polyfluoroalkyl substances (PFAS). Government of Canada. https://www.canada.ca/en/health-canada/services/chemicals-product-safety/per-polyfluoroalkyl-substances.html

King, J. R., Fairfax, J., Barz, E., & Empey, S. (2024). Regulation of ‘forever chemicals’ (PFAS) in Canada. Osler. https://www.osler.com/en/resources/regulations/2024/regulation-of-forever-chemicals-pfas-in-canada

National Institute of Environmental Health Sciences. (2024). Perfluoroalkyl and polyfluoroalkyl substances (PFAS). https://www.niehs.nih.gov/health/topics/agents/pfc

Public Health Ontario. (2023). Focus on per-and poly-fluoroalkyl substances (PFAS). https://www.publichealthontario.ca/-/media/Documents/P/2023/pfas-per-poly-fluoroalkyl-substances.pdf

Savvidou, P., Dotro, G., Campo, P., Coulon, F., & Lyu, T. (2024). Constructed wetlands as nature-based solutions in managing per-and poly-fluoroalkyl substances (PFAS): Evidence, mechanisms, and modelling. Science of The Total Environment, 934(173237). https://doi.org/10.1016/j.scitotenv.2024.173237