Laboratory
Why is Lead in Drinking Water Making Headlines?
Apr. 3 2020
In March 2018, Health Canada published revised guidelines concerning lead in Canadian drinking water. This change reduced the maximum allowable concentration (MAC) of lead in drinking water from 0.01 mg/L to 0.005 mg/L. Reducing exposure decreases the risk of negative health effects caused by lead such as increased blood pressure or kidney problems in adults and delayed neurological development in children.
Sources of lead in drinking water may include the building’s plumbing network (pipes, fittings and solder). This includes the building’s drinking water service line (the water pipe connecting the building’s network to the main drinking water distribution system). When water passes through a lead-containing pipe or fitting, lead may leach into the water. While municipal water supplies are routinely tested for lead, they are not able to measure lead levels outside of their distribution network. A selection of 340 drinking water samples analyzed for lead at a Bureau Veritas laboratory showed that 189 of these samples had detectable levels of lead; 30 of which exceeded the 0.005mg/L guideline.
How Do I Test For Lead?
If you believe that there may be lead in your drinking water, and wish to collect samples to confirm, the appropriate sampling protocols have been established by Health Canada. These protocols are specific to the circumstances of your building. Schools and daycares have been identified as having the most sensitive population and testing at these locations should be a priority.
In a residential household, a Random Daytime (RDT) and a 30 Minute Stagnation (30MS) are used to measure typical exposure to lead. RDT is the collection of one bottle that will give information on the level of lead in your system. The water system is not flushed prior to collection of a RDT sample. A 30MS sample involves filling more than one bottle and occurs after the system has been allowed to sit stagnant for 30 minutes after it has been flushed. The results from the 30MS sample test may provide additional information that can help identify the source/location of the lead.
In schools, multi-dwelling residences and large buildings, sampling should occur annually between June and October when the building is fully occupied. RDT sampling is recommended at drinking water fountains and cold water taps where direct consumption or food preparation may occur. In this scenario, two containers should be collected. The provincial Department of Environment can assist in determining which of these methods is suitable for you. Working with an accredited laboratory will ensure you are given the proper containers and sampling instructions before collection.
What Does Health Canada Recommend?
If your water does contain lead, there are options for minimizing exposure such as using cold water and flushing your pipes before use. Ways to remove lead from your water include the installation of a water treatment system or the replacement of your lead service line/plumbing. An article published by Health Canada provides details on other frequently asked questions regarding lead in drinking water.