The aesthetic objective for iron in drinking water has become stricter with Health Canada moving from ≤0.3 mg/L (≤300 µg/L) to ≤0.1 mg/L (100 µg/L).
Lowering the objective’s limit is intended to minimize the occurrence of discoloured water and bitter or metallic taste due to the presence of iron oxides as well as to improve consumer confidence in drinking water quality, states Health Canada’s Water and Air Quality Bureau.
The previous aesthetic objective, or AO, was established in 1978.
The department released its new Guideline Technical Document for Iron at the end of December 2024 after a 60-day public consultation in late 2023.
Subscribe to our Newsletter!
The latest environmental engineering news direct to your inbox. You can unsubscribe at any time.
Iron is the fourth most abundant element in the earth’s crust and the most abundant heavy metal. It is also an essential element for humans. In most Canadian sources of water, the median iron concentration is below 1 mg/L, states the new Guideline Technical Document for Iron.
“The AO of ≤0.1 mg/L would minimize the occurrence of discoloured water and taste complaints, aid in the removal of co-occurring manganese, ensure that a disinfectant residual is maintained and improve consumer confidence in drinking water quality,” states the new guideline document.
At the municipal level, treatment technologies that are available to effectively decrease iron concentrations in drinking water include aeration, chemical oxidation, and coagulation followed by granular or membrane filtration, as well as adsorption and biological filtration.
Health Canada stated that a review of current literature confirms there is still no need for a health-based guideline for iron.
