Health Canada Consulting on Canadian Drinking Water Guidelines for Uranium and Enteric Viruses

Health Canada Consulting on Canadian Drinking Water Guidelines for Uranium and Enteric Viruses Health Canada is consulting on a new proposed guideline for uranium in drinking water.

The proposal recommends a maximum acceptable concentration (MAC) of 0.02 mg/L (20 µg/L) is proposed for total uranium in drinking water. Read the proposed guidance document.

According to the Executive Summary uranium is widespread in nature and has been identified in many different minerals. It exists in several chemical oxidation states as well as a mixture of 3 radioisotopes. All naturally occurring isotopes of uranium are considered weakly radioactive, however, the principal health effects associated with uranium are due to its chemical toxicity. The focus of this document is limited to uranium’s chemical properties. Health effects related to uranium’s radiological properties are not of concern at levels found in Canadian drinking water supplies.

This guideline technical document reviews and assesses all identified health risks associated with uranium in drinking water. It incorporates new studies and approaches and takes into consideration the availability of appropriate treatment technology. Based on this review, the proposed drinking water guideline for total uranium is a maximum acceptable concentration (MAC) of 0.02 mg/L (20 µg/L).

Health Canada has also published a draft proposed guideline for enteric viruses in drinking water. The proposed guideline for enteric viruses in drinking water is a health-based treatment goal of a minimum 4 log removal and/or inactivation of enteric viruses. Depending on the source water quality, a greater log reduction may be required. Methods currently available for the detection of enteric viruses are not feasible for routine monitoring. Treatment technologies and watershed or wellhead protection measures known to reduce the risk of waterborne illness should be implemented and maintained if source water is subject to faecal contamination or if enteric viruses have been responsible for past waterborne outbreaks. Read the proposed guidance document.

According to the Executive Summary viruses are extremely small microorganisms that are incapable of replicating outside a host cell. In general, viruses are host specific, which means that viruses that infect animals or plants do not usually infect humans, although a small number of enteric viruses have been detected in both humans and animals. Most viruses also infect only certain types of cells within a host; consequently, the health effects associated with a viral infection vary widely. Viruses that can multiply in the gastrointestinal tract of humans or animals are known as "enteric viruses." There are more than 140 enteric virus serotypes known to infect humans.

Health Canada recently completed its review of the health risks associated with enteric viruses in drinking water. This guideline technical document reviews and assesses identified health risks associated with enteric viruses in drinking water. It evaluates new studies and approaches and takes into consideration the methodological and interpretation limitations in available methods for the detection of viruses in drinking water. Based on this review, the proposed guideline for enteric viruses in drinking water is a health-based treatment goal of a minimum 4-log (i.e., 99.99%) removal and/or inactivation of enteric viruses.

CWWA’s Drinking Water Quality Committee is reviewing both proposals and will submit comments if there are concerns with the proposal. Comments are due December 29.