Health Canada Publishes Final Guidelines for Nitra and Nitrite in Drinking Water

The guideline technical document of the Guidelines for Canadian Drinking Water Quality for nitrate and nitrite is now available on Health Canada's web site.

The Guideline establishes a maximum acceptable concentration (MAC) for nitrate in drinking water of 45 mg/L. This is equivalent to 10 mg/L measured as nitrate-nitrogen.

The most common sources of these substances are human activities, including agricultural activities, wastewater treatment, and discharges from industrial processes and motor vehicles. Nitrate and nitrite can also be produced as a result of the nitrification process in source water or distribution systems. The concentration of free ammonia entering the distribution system can lead to nitrification and the potential increase of nitrate and nitrite in drinking water. This issue is fully discussed in the guideline technical document on ammonia in drinking water.

This guideline technical document reviews and assesses all identified health risks associated with nitrate and nitrite in drinking water. It assesses new studies and approaches and takes into consideration the availability of appropriate treatment technology in order to propose maximum acceptable concentrations that are protective of human health and achievable by both municipal and residential scale treatment technologies.

CWWA submitted comments on the draft Guideline during the public consultation period.

Canadian Water and Wastewater Association