Canadian Environmental Health Atlas

Understanding Our Environment is Key to Promoting Health and Preventing Disease

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Standards for Drinking Water

Standards for Drinking Water

Excessive concentrations of arsenic in drinking water have been found in a number of Canadian communities. In Newfoundland, arsenic in various concentrations is found in lake sediments and wells (Figure 1).1 Although the level of arsenic in sediments can provide a clue to the levels of arsenic elsewhere in the area, high concentrations of arsenic can still be found in wells near lakes that have low arsenic concentrations. Similarly, low concentrations of arsenic can be found in wells near lakes that have high concentrations of arsenic.

The New Brunswick Groundwater Chemistry Atlas presents data on a range of chemicals measured in water from domestic wells drilled since 1994 (Figure 2).2 A page from the atlas shows that approximately 6% of water samples taken in New Brunswick exceeded the 2006 maximum acceptable concentration (MAC) for arsenic.

Private Water Sources

Most public water supplies in Canada do not contain excessive arsenic, but private drinking water may be contaminated. Laboratory testing of water to determine arsenic levels is recommended for private water sources.

If water is found to contain arsenic levels above the recommended maximum acceptable concentration, reverse osmosis systems and certain types of filtering units can reduce the concentration and make the water safe to drink. By contrast, using pitcher-type filtration units and boiling water does not reduce the concentration of arsenic. Information about both water testing and water treatment devices can be obtained from local public health officials.