A conversation has started in Canada that could mean a brighter future for our children. And not just by investing in education. This new conversation is about focusing our collective attention on a serious threat to tiny developing brains: toxic exposures.

Since the Second World War, there has been a dramatic increase in the production and use of chemicals, including many that are now known or suspected to be toxic. We have been studying the impact of these toxic chemicals, or toxins, for over 30 years and reached an inescapable conclusion: little things matter. Toxins can have a lifelong impact on children, and that extremely low levels of neurotoxic chemicals can permanently alter brain development.

Pregnant women and children are regularly exposed to toxins such as mercury, lead, PCBs, bisphenol A and pesticides. Moreover, these toxic exposures do not occur in isolation; we are all continually exposed to many toxins and dozens of inadequately tested chemicals.

The amount of toxins in a typical child, which is measured in parts per billion (ppb), is deceptively small. One ppb is about two tablespoons of sugar in an Olympic-size swimming pool. But chemicals can do serious damage, even at very low levels.

Indeed, chemicals designed by drug companies to alter behaviours, such as Ritalin, a drug commonly used to treat children with ADHD, affect the brain at levels about the same or even lower than toxins found in the blood.

In the 1960s, hundreds of children in North America died from lead poisoning every year. Since then, much lower levels of exposure to lead have been shown to result in learning deficits and brain disorders, like ADHD. In fact, the World Health Organization and other agencies agree; there is no safe level of lead exposure.

Other, newer toxins are now regularly shown to decrease children’s intellectual abilities. For example, a flurry of recent studies shows that as the level of PBDEs, a type of flame retardant, increases in pregnant women’s blood from 10 to 100 ppb, the IQ scores of their children drop by about 5 points. We see a similar pattern with organophosphate pesticides, which are regularly found in our foods.

The impact of toxic chemicals on the developing brain is permanent. Children who are more heavily exposed to toxins will not reach the same peak intellectual ability as those who have lower exposures.

These studies show that there is no safe level of exposure. They also indicate that the way governments regulate chemicals — which assumes there is a safe level — fails to protect children.

Little shifts in children’s IQ scores or behaviours have a big impact on the number of children who are challenged or gifted.

U.S. data shows that widespread exposure to a neurotoxin, like lead, that causes a 5-point drop in IQ across a population would result in a 57 per cent increase in the number of U.S. children who are challenged, from 6 million to 9.4 million. There would also be a corresponding decrease in the number of children who are gifted. When you add the impact of another brain-damaging toxin, like flame retardants, the number of challenged kids would rise to over 11 million. We do not have similar research data here in Canada, but the pattern is likely similar.

Although many — if not most — chemicals are not associated with these brain-stunting effects, the cumulative impact of ongoing exposures to lead, mercury, flame retardants, pesticides and other neurotoxic chemicals is overwhelming to imagine.

In Canada and the U.S., most chemicals are used in consumer products and released into the environment before they are tested for toxicity to the developing brain. By allowing children to be exposed to toxins or chemicals of unknown toxicity, we are unwittingly using our children as part of a massive experiment.

It does not have to be this way. Like the European Union, we could shift the burden of proof and require that industry prove the chemicals they use are not toxic before they enter the market.

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Last week, doctors, nurses, midwives, public health professionals and environmental health researchers from across Canada convened at the University of Ottawa to discuss the implications of this and other evidence about early-life exposures to toxic substances. This is a conversation about the health of individuals and the well-being of Canadian families, but it is equally a conversation about the prospects of our nation — and it’s time we all joined in.