Yes, thank you.
First I would like to applaud your efforts, and Health Canada's efforts, to update the guidance on lead and to modernize the water service lines in Canada to protect Canadians. Protecting the health of Canadians is to a large extent about ensuring that the water we drink, the air we breathe, and the food we eat are clean and healthy.
My research over the past 25 years has been primarily focused on protecting children from lead poisoning, and I'll focus my comments today on lead toxicity for the most part.
My early studies quantified the various sources of lead that contribute to children developing lead poisoning, including paint, house dust, soil, and water. We found that water is one of the most important sources of lead for children, pregnant women, and the rest of us.
We found that at high levels of exposure, lead damages the prefrontal cortex—that's the part of the brain that makes us most distinctly human—and elevates the risk that children will develop anti-social behaviours such as delinquency, and even criminal behaviours. We also found that children who were exposed to high levels of lead were at increased risk for developing other types of behavioural problems, such as ADHD. In fact, we found that about one in five cases of ADHD, or 600,000 cases in the United States, were due to lead exposure.
Low-level lead exposure in pregnant women has also been linked to children being born too small and too soon.
Finally, we found that lead is toxic at the lowest levels of exposure. The World Health Organization has concluded that there is no safe level of lead in children's blood.
Although we focus primarily on the impact on children's health, lead is an established risk factor for hypertension, chronic kidney disease, and essential tremors in adults. It is also suspected, but not proven, to increase the risk of death from ischemic heart disease—that's when your heart suffocates over many years from lack of oxygen—and dementia.
While we've made progress in reducing lead in our environment, water pipes and fountains remain an important source of lead for many Canadians, especially for smaller communities and first nation communities.
Currently Health Canada relies on a guidance of 10 parts per billion of lead in water. That's the equivalent of about 10 tablespoons in an Olympic-sized swimming pool. I concur with Health Canada's conclusion that 10 parts per billion is no longer protective. Children who live in homes with water lead levels above five parts per billion have, on average, a one-microgram-per-decilitre increase of blood lead, which is estimated to reduce their intellectual ability by about one to one and a half IQ points. Women who live in homes with water lead levels above five parts per billion have about a 30% increase in blood lead levels.
As Health Canada has said, the maximum acceptable concentration of lead in water should be reduced to five parts per billion, and over the next 10 or 20 years steps should be taken to reduce it even further.
I'd like to stop there and be available for questions later.
Thank you.