Health Canada has published two new drinking water Quality Guidelines for public consultation
The new proposed guideline for barium will recommend a maximum acceptable concentration (MAC) of 2.0 mg/L (2,000 µg/L) in drinking water. According to the consultation document, studies have found links between the ingestion of barium and unwanted effects on blood pressure in animals and humans. However, adverse effects on the kidneys have shown the strongest association with chronic oral exposure to barium. In humans, effects have been observed on the kidneys following exposure to high levels of barium in poisoning events; in animals, kidney effects are considered the most sensitive health effect associated with long-term ingestion of barium, especially in mice, the most sensitive species. Consequently, the proposed MAC of 2.0 mg/L has been established to be protective of the general population, based on studies of kidney effects in mice.
The consultation document is available at:
A second consultation on chloramine was also published. Health Canada recommends that it is not considered necessary to establish a guideline for chloramines in drinking water, based on the low toxicity of monochloramine at concentrations found in drinking water. Any measures taken to limit the concentration of chloramines or their by-products in drinking water supplies must not compromise the effectiveness of disinfection.
The document goes on to offer a full exploration of the use, monitoring and environmental impacts of chloramines.
Comments on the chloramine guideline are due January 25, 2019, while Barium comments are due February 15, 2019.
CWWA’s Drinking Water Quality Committee is reviewing the proposed guidelines and will submit comments if there are any concerns.