At least four new public consultations for water quality are on track to begin in fall 2024, ranging from arsenic to haloacetic acids, as well as trihalomethanes and radiological parameters.
Water quality experts from Health Canada’s Water and Air Quality Bureau shared the update as part of the Window on Ottawa webinar series hosted by the Canadian Water and Wastewater Association (CWWA).
Arsenic
Anne Vézina, a senior science advisor in Health Canada’s Water and Air Quality Bureau, noted some considerations to revise the 2006 arsenic guidelines based on new science that explores additional health risks for humans, particularly a number of cancers.
“We alluded to it in the previous guideline, but we’ve gotten a lot more information on how arsenic can accumulate in the distribution system and be released back into the water and end up at the tap,” noted Vézina.
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The arsenic guideline currently has a maximum acceptable concentration (MAC) of 10 micrograms per litre based on treatment achievability. The health-based value is 0.3 micrograms per litre.
The Federal-Provincial-Territorial Committee on Drinking Water (CDW) approved a draft report update for arsenic in February that is expected to circulate for consultation in the fall.
Radionuclides
France Lemieux, head of the Materials and Treatment Section in Health Canada’s Water and Air Quality Bureau, noted that an update is expected in the fall for radiological parameters. The current guideline was published in 2009 with a reference level of 0.1 millisieverts. The upcoming document considers a new reference level based on more recent international assessments of human health to explore uranium, lead, radium, and other radionuclides.
“We’ll be looking at sources of natural origins that weren’t really previously addressed in the previous version of the radiological parameter guidelines,” explained Lemieux.
Disinfection Byproducts
Trihalomethanes may also be explored in a public consultation this fall, potentially updating the 2009 MAC of 100 micrograms per litre. Lemieux said the department took into consideration a more refined risk assessment approach, benchmark and dose modeling to create less uncertainty in terms of an approach.
The current haloacetic acids (HAAs) guideline dates back to 2008 and with a MAC of 80 micrograms per litre.
“One of the limiting factors was the technological limitation with reducing individual HAA levels while maintaining effective disinfection,” explained Lemieux. “That was a challenge for the jurisdictions to deal with.”
PFAS
The consultation period for PFAS ended in April 2023, and while still subject to approval, an update is expected during late summer 2024.
Corrosion and Fluoride
Health Canada officials said they also expect guideline updates on corrosion control in early 2025, which aims in part to clarify building owner responsibility. Updates are also expected for fluoride, which has had a lot of new science emerge since the 1.5 milligrams per litre guideline was established in 2010.
The CWWA’s Window on Ottawa webinar series runs until July 19, with upcoming sessions on cybersecurity, the Canada Infrastructure Bank, and the Canadian Infrastructure Benchmarking Initiative (CIBI).
