Drinking water contaminated with lead is a public health concern. According to the WHO, lead is one of few substances known to cause direct health impacts through drinking water. The WHO guidelines for drinking water quality establish a value of 10ppb (10 μg/l), on the basis of treatment performance and analytical achievability. The organisation recognises that it is no longer a health based guideline value and concentrations should be maintained as low as reasonably practical.
Investigators have compiled the results of 12,000 water tests done between 2014 and 2018 in eleven Canadian cities, and one third of the samples show lead levels that exceed 5 parts per billion (ppb), the national safety guideline set by Health Canada, reports the BBC. The project was the idea of journalist Robert Cribb, from the Toronto Star, who became interested after water tests in his own home some years ago revealed high lead levels: ‘This is a far, far bigger issue than any one journalist or one organisation can tackle’, he said to the BBC.
Concordia University’s Institute for Investigative Journalism facilitated the collaborative investigation, known as ‘Tainted Water’, the largest of this kind in Canadian history, with the participation of nine universities, 10 media companies and more than 120 reporters, editors, students and faculty members across the country. They spent one year assembling the data (including more than 700 access-to-information requests) to find that, while one third were over the safe level of 5ppb (5 μg/l), 18% of the samples exceeded the US limit of 15ppb (15 μg/l).
Some areas studied were Montreal, the second most populated city in the country, Oakville, a wealthy part of Greater Toronto Area, and Regina, the capital of Saskatchewan. The Toronto Star reported results in some cities were similar to those found in Flint during the 2015 water crisis. In addition, residents across the country volunteered to carry out tests of their drinking water for lead in 32 cities. 260 older homes we sampled, and in 39% the lead level exceeded the federal guideline.
The main source of lead in Canada’s drinking water is old pipes and service lines connecting water mains to the home’s internal plumbing. It is estimated that around 500,000 homes still have lead service lines, according to a government report. Barriers to lead line replacement include cost, insufficient data, lack of awareness, and jurisdictional complexities concerning ownership of different sections of the service line. Corrosion control is also used by water utilities, adding chemicals to minimise lead release into the drinking water.
Canada is one of few industrialised nations without national drinking water standards. Health Canada has a recommended guideline, and then provinces and municipalities can set their own regulations. The study revealed lead tests are done differently across the country, sometimes not done at all, and testing results are rarely made public. The lack of federal oversight contrasts with the situation across the border in the U.S., where the Environmental Protection Agency sets legal standards for lead testing and public disclosure of the results.