When Hannah Ainslie moved, one of the first things she did was test her drinking water. While taking a public health program for new mothers, she had discovered that Toronto residents in older houses should test their water for lead. So when she moved into her new house in an older area of town, she tested the water within the first few weeks. Sure enough, the lead content was slightly above the cutoff point of 10 parts per billion (ppb).
“At the time, I had a three and a half year old and a two year old, and I was pregnant,” she says. “Thank God we caught it when we did.”
Her family decided to replace the lead pipe that connected the house to the main line on the road. It was a two-step process: first they had to privately replace the part of the pipe that was on their property, and then the city would replace its section. Ainslie paid $2,000 to change her side, then requested that the city change theirs. Five months and many follow-up calls later, the city did.
Ainslie found the delay frustrating, and she worries about others who aren’t aware they should test their water or can’t afford to replace their pipes. “In 2016, [lead in drinking water] isn’t something that should be a problem,” she says. “Safe water is a basic human right. I’m paying $5,000 a year in property taxes, and I can’t even ensure that my water is safe.”
Lead is often seen as a problem of the past. Since Canada began phasing out lead in gasoline in the 1970s, our exposure has declined by about 75%. But the recent crisis in Flint, Michigan, has brought lead back into the spotlight. A state of emergency was declared in the city after high levels of lead were found in the drinking water, with many homes having levels higher than 150 ppb.
Canadian households do too. There are 35,000 homes in Toronto with lead pipes, and about 165,000 more across the country. So what can municipalities do to help reduce our exposure – and should we be worried about the impact on our health?
The scope of the problem
The number of houses with lead pipes varies widely across the country, with most of the risk being based on the age of the houses. The most important source is lead pipes, which were widely used before 1950. Less common sources are lead solder, which was used in some pipes until 1986, and older faucets.
Statistics aren’t available for the number of lead lines in each province, partially because some cities don’t know which houses still have lead pipes. But in 2007, after the city of London, Ont., reported high lead levels in 25% of the older homes it tested, the Ontario Ministry of the Environment ordered municipalities across the province to test for lead in the water. Toronto did four rounds of testing between 2007 and 2009, and found that on average 20% of residential tests had lead water levels above 10 ug/L. (A Toronto Star investigation last year looked at only the 15,000 samples voluntarily taken by homeowners between 2008 and 2014, and found that 13% had high levels of lead.)
In 2014 to 2015, 95% of the residences tested across the province met the standard for lead. In Alberta, those percentages are lower, with lead estimated to affect 2% of Edmonton homes, and only 0.02% of those in Calgary.
The 2007 Ontario legislation also made it mandatory for older day cares and all schools to test their water, but that’s not the case in other provinces. Just this month, Prince Rupert, B.C., found that 48% of the schools tested had elevated levels of lead in their drinking water.
In adults, chronic lead exposure appears to increase the risk of hypertension, with a doubling of blood level leading to an increase in blood pressure of about 1 mm Hg. But the highest risks are for children who are under six years old and for pregnant women. They include lowered IQ scores and behavioural issues such as ADHD.
Lead is more likely to affect children who are anemic or don’t get enough calcium, since that causes them to absorb lead more readily. Children who come from low-income households, who are more likely to have nutritional deficiencies and more likely to live in poor quality housing, are also more at risk. Similarly, new immigrants and refugees are more likely to have higher blood lead levels, for reasons that aren’t clear, but may include coming from countries with higher lead exposure, not being informed about the risks of lead, and being more likely to be in low-income families.
How municipalities are addressing their lead pipes
Cities should take a “two-pronged approach” to reducing lead in the water, says Graham Gagnon, director of the Centre for Water Resources Studies at Dalhousie University. “One is to wrestle with lead service line connections by actively encouraging homeowners to remove them, and the other is to treat the water so it’s as corrosion-free as possible.”
To start, municipalities should let homeowners know that they may have lead pipes – a task that’s more complicated in places like Toronto, where the city doesn’t know exactly which houses have them. Toronto has a variety of outreach campaigns to reach residents, which have included sending 200,000 cards in the mail to residents of older homes that are suspected to have lead pipes. Municipalities also warn homeowners when replacing the city side of the pipes, as that can cause lead levels to spike.
Concerned homeowners can do a free water test or dig into whether they have lead pipes. Howard Shapiro, associate medical officer of health at Toronto Public Health, says the latter is preferable. “Toronto Public Health is trying to de-emphasize the role of testing,” he says, explaining that the results are variable depending on how much water has been run through the plumbing before the sample was taken, the season, and what part of the plumbing the water has been sitting in. Because of that, he says, “it really should be about whether the person has a lead pipe.”
If they do, the next question for homeowners might be if they can afford to change it. Replacing the pipes generally costs between $2,000 and $5,000. Some cities help reduce that barrier by offering loans. In Ottawa, Hamilton and London, residents can finance the replacement through the city and pay it back over 10 years on their property tax bill. Toronto recently voted down a plan to offer interest-free loans. A less expensive option is to use a filter that’s certified to remove lead from the water, and many cities offer discounted or free filters to those who qualify.
The other side of the process is corrosion control. Lead pipes are more likely to corrode if the water is very acidic. So adding chemicals to the water can change the alkalinity and reduce the risk. Phosphate, the gold standard, reduces the risk 100 to 500 fold.
Some cities are doing this very successfully, but others seem to be ignoring the issue. Gagnon worked with the Canadian Water Network on a report about what municipalities were doing about lead. “In our survey it was clear that some cities were going out of their way by adding phosphate, and having a lead service program,” he says. “And some cities – and these weren’t small cities – weren’t doing anything.”
Blood lead levels in Canadians
To judge the health impacts of all this, “we’ve got to look beyond lead in water – we have to look at lead in people,” says Ray Copes, chief of environmental and occupational health at Public Health Ontario.
Overall, that’s a good news story. In the 1970s, Canada began phasing out leaded gasoline and lead solder in cans, and limiting the amount of lead allowed in paint. Since then, blood lead levels of Canadians have steadily declined.
In 1978 to 79, 25% of Canadians between six and 79 years old had blood lead levels at or above the 10 micrograms per deciliter (μg/dL); today that number is fewer than 1%. According to the latest Canadian Health Measures Survey data, the average Canadian has a blood lead level of 1.0 μg/dL.
“The mean blood lead levels in the Canadian population continue to fall, and that’s true even in kids. Overall, it’s really good news. But the question is, are there exceptions?” says Ray Copes, chief of environmental and occupational health at Public Health Ontario. “These results are very reassuring for the population as a whole but are not very informative as to the level in the top, say, 0.1% or 0.01% of the population.”
A 2013 study investigated the impact of household water on blood lead levels of children in older boroughs of Montreal, and found reassuring results. While water had a significant impact on blood lead levels, blood lead levels were generally low, with a mean of 1.35 μg/dL. A 2008 Hamilton study found similar results.
However, data from Canada isn’t as robust as it is in the U.S. Some argue we’re far behind the States when it comes to tracking lead levels and legislating safe environments for children. “We don’t do surveillance for blood lead levels in young children in Canada, so we don’t have as good a grasp of the problem here,” saysBruce Lanphear, a professor at Simon Fraser University who is studying the impact of toxins on children. “But the US is in worse shape because there are more inequities, and housing seems to be less well maintained [resulting in more flaking lead paint.]”
A compromise might be to look at the results of the 10,000 blood lead tests physicians already order every year in Ontario. Currently, those results aren’t available to be analyzed. “I find it surprising that we don’t systematically look at the results,” says Copes. It’s difficult to tell in Ontario, since blood lead tests aren’t automatically reported and available to be analyzed. Quebec, on the other hand, requires that all blood lead levels over ≥ 10 μg/dL be reported, and BC is currently contemplating a similar requirement.
Over the past 40 years, it has also become clear that there are health effects to lead well below Canada’s blood lead level cut off of 10 μg/dL. In response to more recent data, the CDC changed its acceptable levels to 5 μg/dL for children in 2014, and Health Canada’s 10 ug/dL guideline is being reviewed.
“There’s evidence that even at lower levels, it’s affecting people’s health,” says Shapiro.