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Hi all…Health Canada has released the Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Aluminum (to be published in Canada Gazette, Part I on Saturday, March 6, 2021). There are changes from the 1998 guideline, which it replaces, and from the August 30 2019 proposed values when it was posted for comment. The new “maximum acceptable concentration (MAC) for total aluminum in drinking water is 2.9 mg/L (2,900 µg/L) based on a locational running annual average of a minimum of quarterly samples taken in the distribution system. The operational guidance (OG) value for total aluminum in drinking water is 0.100 mg/L (100 µg/L) to optimize water treatment and distribution system operations. This value is based on a locational running annual average. The sampling frequency required to calculate the locational running annual average will vary based on the type of treatment facility and the sampling location.”

The difference is the increase in the 2019 proposed operational goal (OG) from 0.05 mg/L to 0.100 mg/L total aluminum. There were substantial concerns expressed in response to the request for public comment, particularly with respect to the OG, which while having been increased does not appear to address its impact regarding jurisdictional interpretation of OGs from province to province. Note that the two values have slightly different definitions of annual average (underlined above). In any event, I have not read through it yet so I cannot comment further. Here’s the link:


Here are the 1998 and August 2019 MACs and OGs for reference:

  • The August 2019 version for comment proposed a “maximum acceptable concentration (MAC) of 2.9 mg/L (2,900 µg/L) for total aluminum in drinking water, based on neurological effects observed in rats. An OG value of 0.050 mg/L (50 µg/L) is proposed for total aluminum to optimize water treatment and distribution systems.”
  • The 1998 existing guideline technical document on aluminum recommended OG values for treatment plants using aluminum-based coagulants was as follows: “less than 0.1 mg/L (100 µg/L) for conventional treatment plants and less than 0.2 mg/L (200 µg/L) for other types of treatment systems (e.g., direct or in-line filtration plants, lime softening plants). A health-based guideline was not established [at that time], as there was no consistent, convincing evidence that aluminum in drinking water could cause adverse health effects in humans.”