WATER
Regulating and removing PFOA and PFOS to protect public health By Saleha Kuzniewski
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mong per- and polyfluoroalkyl substances (PFAS), only perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been sufficiently studied to develop regulations in Canada. Chemicals are regulated in Canada under the Canadian Environment Protection Act, 1999 (CEPA, 1999). CEPA, 1999 provides the legislative foundation for environmental and health protection in Canada. It gives authority to the Minister of Health to regulate toxic substances, including PFOA and PFOS. Toxic substances are defined in CEPA, 1999 in terms of the risks they pose to human or environmental health. Part 5, Section 64 of CEPA, 1999 says that a substance is toxic if it enters the environment in a high concentration, or under the conditions that it may have a harmful effect on the environment, or may constitute a danger to the environment or human health. To assess whether a substance is toxic, information is collected in regard to the health effects from exposure to the substance as specified in Part 5, Section 68 of CEPA, 1999. Weight of evidence and precautionary principles are applied when conducting and interpreting results from the assessment of the substance and from reviews of the decisions from another jurisdiction, as specified in Part 5, Section 76.1, and substances that are toxic are added by the Minister of Health to the list of toxic substances called Schedule 1. In 2006, Environment Canada and Health Canada concluded from their studies that while PFOS were not a health concern at the exposure levels at that time, they declared PFOS and its salts to be environmentally toxic and added these to Schedule 1 of CEPA, 1999. Two years later, in 2008, the Canadian industry shifted from using PFOA and PFOS to other PFAS as alternatives. This move 58 | February 2022
A lot can be learned from samples of PFAS in the soil, sediment and water taken on site. Credit: Adwo, stock.adobe.com
was on par with the PFOA Stewardship Program launched by the U.S. EPA and eight major companies in 2006 to reduce the emission and products’ content of PFOA by 95% by 2010 and to completely eliminate PFOA content by 2015. In 2018, Health Canada set the maximum acceptable concentration (MAC) in drinking water at 0.2 µg per litre for both PFOS and PFOA. Health Canada also recommends the use of activated carbon filters and reverse osmosis (RO) systems to treat well and tap water and to test the water for concentrations of PFAS prior to, and after installing the treatment. As both PFOS and PFOA could be found together in water, testing is not straightforward. Therefore, Health Canada has published an equation for this situation: the sum of the concentration of PFOS in water divided by the MAC for PFOS and the concentration of PFOA in water divided by the MAC for PFOA. The MAC here is a fixed value: 0.2 µg per
litre, as mentioned above. For testing the concentrations of PFAS other than PFOS and PFOA, Health Canada has published a table on Drinking Water Screening Values (DWSV). This table consists of the DWSVs for a number of PFAS and is available in the publication by Health Canada Water Talk – Perfluoroalkylated substances in drinking water, 2019. According to this, while the DWSV values are based on limited review of the existing science and not peer-reviewed, the table is based on assessment done by other jurisdictions in Canada. There is no risk from the drinking water if it has a concentration of a PFAS below the DWSV. If the concentration is higher, then the above-mentioned treatment options are recommended. Activated carbon filtration, one of the technologies recommended by Health Canada for removing PFOA and PFOS from drinking water, is effective as it is highly porous and its large surface area allows chemicals to adsorb to it. Adsorp-
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