Lead exposure in children, even at very low concentrations, is detrimental to academic success through the end of high school, according to a new Quebec study on the subject.
This research was conducted using data from the Quebec Longitudinal Study of Child Development (ELDEQ), which measured the concentration of lead in the blood (called “blood lead”) in a cohort of 10-year-olds on 2008.
His school career was then documented until the end of high school.
These data have established that lead exposure is associated with an increase in inattention and hyperactivity, which leads to lower performance and delays in schooling that can lead to dropout.
“Lead affects behavior that affects school performance,” summarizes Gina Muckle, a professor at the University of Laval School of Psychology who oversaw this study.
The impact is documented even though 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 Université Laval.
“Even with very, very low lead concentrations, you still see an impact,” he says.
The average blood lead level in 10-year-olds was 1.1 micrograms per liter, 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 the 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 to make our children work as well as possible, we need to eliminate so many sources of exposure as much as possible of the environment, ”says Ms. Muckle.
Lead acts on the brain, more particularly on the nervous system, which is developing in children. “This is what makes it a much more at-risk population,” says Claudia-Béatrice Ratté.
More or less lead now?
Although lead levels in the environment have been declining since the 1990s, it is still unclear whether the level of lead exposure in children has actually decreased because the source of exposure has changed, explains the professor at the University of Laval.
Now, it is mainly the pipes that carry water to homes, kindergartens and schools that are largely responsible for the exposure of young people to lead.
“These pipes are aging and small lead particles end up in the water. This source of exposure has not diminished for children living in houses built before the 1990s,” he says.
In the school network, water quality testing has been conducted in all schools in Quebec in recent years. Education Minister Jean-François Roberge said this week that all water points should be met by the start of next school year. In some cases, however, students will still have to run water before drinking it.
But it’s not just in schools that you have to worry about water quality, Ms Muckle adds.
“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 needs to be introduced in the course of the education network “, he says, although he underlines 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 micrograms per liter