Keeping Drinking Water Safe: New Guidelines for PFAS in Canada
What are PFAS?
Per- and Polyfluoroalkyl Substances, or PFAS, represent a large group of synthetic chemicals that have been in use since the 1950s in industry and consumer products as water, stain, or oil repellent coatings and firefighting foams. Recognition of their persistence in the environment and potential to impact human health have led to new guidelines and Maximum Acceptable Concentration (MAC) levels being set by Health Canada in December 2018 for two PFAS chemicals in drinking water - perfluorooctane sulfonate (PFOS) and perfluoroctanocic acid (PFOA)..
Why should we care about PFAS?
In 2006, Environment Canada and Health Canada concluded that some PFAS chemicals are highly persistent, mobile in the environment, can accumulate in living organisms, and may also have the potential to cause immediate or long-term harmful effects on human health and the environment. The Canadian Health Measures Survey (cycle 1 and cycle 2) included several PFAS chemicals amongst the numerous human biomonitoring agents that Health Canada monitors. Of the two cycles studied (2007-2009 and 2009-2011), results show that most Canadians carry low levels of PFOA and PFOS in their blood.
The potential health effects of PFAS exposure documented in a recent review include probable links with high cholesterol, thyroid disease, pregnancy-induced hypertension, ulcerative colitis, and kidney and testicular cancer, and positive association between exposure and dyslipidemia, immunity, and renal function in children. In 2018, the US Centre for Disease Control (CDC) published interim guidance for clinicians responding to patient concerns about exposure to PFAS.
PFAS exposure in Canada
PFAS are not manufactured in Canada but they may be present in imported products and finished goods. In 2008 Canada prohibited the use, sale, and import of PFOS or PFOS-containing products with exceptions for products used in firefighting and the military as well as some ink and photo media uses.
Sites with a history of using firefighting foams, including some airports and military bases for training or emergency situations, may be a source of PFAS chemicals in the environment with the potential to leach into nearby groundwater sources. There has been concern about the potential health effects of PFAS found in drinking water near sites with a legacy of PFAS use and Transport Canada has been investigating the presence of PFAS near fire training areas at some Canadian airports.
Applying the new guidelines – collecting the evidence
Provincial and territorial agencies responsible for ensuring safe drinking water supplies will now be considering what these new guidelines mean for their region, and what drinking water sources may be impacted by a legacy of PFAS use before adopting new guidelines into practice. In the consultation running up to the new guidelines, only Saskatchewan, Quebec, New Brunswick, Newfoundland and Labrador and the Yukon provided statements of anticipated impacts. Implementation of these guidelines will likely need further assessment and study to be carried by the appropriate drinking water authority in affected jurisdictions. PFAS will likely remain in focus as more research is carried out to understand exposure pathways and related health outcomes for both legacy and new and emerging PFAS chemicals in Canada.