Exposure to PFAS, or scientifically known as per- and polyfluoroalkyl substances, can occur from any number of consumer products, outdoor and indoor air, food, or drinking water. This exposure, along with the limits of exposure, is only now being understood as sampling and monitoring are required.
According to Health Canada, new PFAS are continually being developed and reported to the government of Canada. This can cause potential risks to human health and the environment. But like many innovations or technologies, the full understanding and long-term effects are still to be determined.
We know that PFAS can affect a person’s liver, kidney, thyroid, metabolism, immune system, and reproductive systems. Each person will have different levels based off exposure, general health, and their unique individuality.
PFAS can be excreted from the body in several ways. While testing and research is ongoing, what is understood is that it can leave the body through urine, blood during menstruation, and breast milk. However, for those who have kidney disease, it may be difficult to excrete PFAS in urine as compared to healthy individuals.
PFAS is a group of thousands of synthetic chemicals that are used in industry and consumer products. The most common types are perfluoro octane (PFOS) and perfluoro octanoic acid (PFOA). What we know about PFAS is that it doesn’t breakdown easily and persists for long periods of time. When applied to textiles, it repels dirt, water, and grease. These base properties created products that include non-stick cookware, sunscreens, textiles, pharmaceuticals and cosmetics, vehicle components, fire-fighting foams, fire retardants, packaging materials for food, pesticides, and electronics.
It’s important to understand that PFAS doesn’t breakdown in nature readily and stay in the environment for long periods of time thus dawning the term forever chemicals.
Recommended treatment
In 2024, Health Canada published the Objective for Canadian Drinking Water Quality – Per- and Polyfluoroalkyl Substances that recommends a treatment-based value for a group of PFAS in Canadian drinking water. This objective sets a goal for a maximum level of contaminants in drinking water while accounting for current treatment technologies and testing methods.
The objective outlined by Health Canada sets the value at 30 ng/L. This value is the sum of 25 specific PFAS and is to reduce PFAS exposure in drinking water with a test result of “non-detect.”
There are various options available when looking at PFAS treatment. Ion exchange resins, high-pressure membranes, and granular activated carbon adsorption can all be effective. These technologies have advantages and disadvantages depending on the composition and concentration of the PFAS substances. The selection of the technology requires an understanding of the source water chemistry and the treated water goals or objectives. Separately selected or configured together, correctly designed and applied, these technologies can be effective municipal drinking water treatment plants, institutions, and point-of-entry or point-of-use for homes.
According to a study published by the U.S. EPA, granular and powdered activated carbon treatment is the most studied treatment for PFAS removal. Adsorption captures PFAS both by physical and chemical processes and accumulates PFAS in the highly porous surface area provided by activated carbon. Carbon is effective in adsorbing long-chain PFOS and PFOA but not as effective with short-chain PFAS like perfluoro butane sulfonate (PFBS).
An alternate treatment option is anion ion exchange resin. Ion exchange resins are made up of highly porous, polystyrenic materials. Positively charged anion resins attract negatively charged PFAS ions. Ion exchange resin removes PFAS through two mechanisms — ion exchange and adsorption. With ion exchange, there is no regeneration of the resin, therefore no contaminant waste stream.
Removing PFAS
High-pressure membranes, such as reverse osmosis and/or nanofiltration are effective at removing PFAS. Applied research has shown that these types of membranes are typically greater than 90 per cent effective at removing a large range of PFAS; this includes short-chain PFAS. Reverse osmosis suits point-of-use type applications. One disadvantage is the waste stream is concentrated with PFAS and may require additional considerations.
For residential consumers, any of the discussed treatment technologies can provide a cost-effective point-of-entry or point-of-use option. Points to consider for both the installer and consumer include: Will this be a whole home or one tap installation? What are the costs (installation, maintenance, water consumption, disposal)? What monitoring or testing requirements are needed? How long will the application treat water before service? Is the system NSF or CSA certified? What qualifications will the business selling, installing and eventually servicing need to deal with PFAS?
The water treatment industry has well qualified businesses and individuals, but PFAS is new to many. Those who are working with PFAS need to fully understand the risks, implications, exposure and requirements of providing the consumer with a system that will remove these chemicals consistently.
As PFAS awareness increases and testing for these contaminants increases, consumers and municipalities have real decisions to make. The cost of infrastructure and treatment at a municipal level is one option, but so is the consumer’s point of entry or point of use. To clarify, consumers could be anyone, any business, institution and or even a municipality looking for a cost-effective user-based solution.