Lead associated with low secondary school performance

Exposure to lead in children, even at very low concentrations, is detrimental to academic success until the end of high school, according to a brand new Quebec study on the subject.

This research was carried out using data from the Longitudinal Study of Child Development in Quebec (ELDEQ), which measured the concentration of lead in the blood (called “blood lead”) in a cohort of children from 10 years in 2008.

Their school career was subsequently documented until the end of high school.

These data have established that exposure to lead is associated with increased inattention and hyperactivity, which leads to poorer performance and delays in schooling that can lead to dropping out.

“Lead affects behavior which affects school performance,” summarizes Gina Muckle, professor at the School of Psychology at Laval University who supervised this study.

The impact is documented even if the concentrations observed in almost all cases are well below the recommended threshold, adds Claudia-Béatrice Ratté, who carried out this research as part of her master’s degree at Laval University.

“Even with very, very low lead concentrations, you still see an impact,” she says.

The average blood lead level of 10-year-old children was 1.1 micrograms per litre, well below the recommended 5 micrograms.

The most exposed children had levels of 7 micrograms, but the blood lead level of more than 95% of young people was below the recommended threshold.

“What our data shows is that there is no safe threshold. From a prevention perspective, if we want to put the odds on our side so that our children function as well as possible, we must remove as many sources of exposure as possible in the environment,” says Ms. Muckle.

Lead acts on the brain, more particularly on the nervous system, which is in full development in children. “This is what makes it a much more at-risk population,” emphasizes Claudia-Béatrice Ratté.

More or less lead now?

Even though lead levels in the environment have been declining since the 1990s, it’s still unclear whether the level of lead exposure in children has actually decreased because the source of exposure has changed, explains the professor. from Laval University.

Now, it is primarily the pipes that carry water to homes, daycare centers and schools that are largely responsible for lead exposure in young people.

“These pipes are getting old and the little lead particles end up in the water. This source of exposure has not diminished for children who live in houses built before the 1990s,” she says.

In the school network, water quality tests have been carried out in all Quebec schools in recent years. All water points should be compliant by the start of the next school year, the Minister of Education, Jean-François Roberge, said this week. In some cases, however, students will still have to let the water run before drinking it.

But it’s not just schools where you have to worry about water quality, adds Ms. Muckle.

“If there is lead in the water system of an old school in Limoilou and the student lives in a house a few blocks away, it is the same water and the child is doubly exposed. This is not a problem that should be just shoveled into the course of the education network, ”she says, while stressing that it is still a “current public health problem”.

lead in water

Maximum concentration acceptable

• 5 micrograms per liter (federal standard adopted by Quebec)

Average concentration observed during the study

• 1.1 microgram per liter