Wildfires in 2023 may have caused temporary spike in lead levels in N.W.T. youth, researcher says
Follow-up testing found levels had dropped among some of the original subjects who had higher lead
A researcher is looking into how 2023's wildfires in N.W.T. may have been responsible for a temporary spike in lead levels detected in some young Yellowknife, Dettah and Ndilǫ residents.
This comes as followup results from some of those test subjects this year show that lead levels in their blood and urine have since dropped.
Brian Laird is a professor in public health science at the University of Waterloo and a member of the project team of the Health Effects Monitoring Program. The program is a requirement of the environmental assessment for Giant Mine's cleanup plan, to determine whether contaminants from the mine affect human bodies.
He said in 2023, researchers analyzed the urine of 388 participants between the ages of three and 23 and found the levels of lead in those people had increased substantially from five years earlier.
"So all of the kids that had seen particularly high levels of lead were invited to do more follow-up testing," he said.
Of those tested in 2023, 22 people with higher levels of lead were tested again in 2024-25, using blood or urine samples.
"And we got those results back very recently and there was some very reassuring news in that the vast majority of those kids, those levels of lead had dropped significantly."
Laird said they also offered blood testing to those with high lead levels and the results from those tests found the lead levels well below the action levels from the Centre for Disease Control (CDC). The CDC recommends testing if blood lead level is at a certain threshold.
Lead exposure can lead to lower IQ, hyperactivity, slowed growth and anemia, health officials say. Those most at risk include children under six, infants and pregnant people.
Wildfires the common factor 'that matches timeline'
As for why higher lead levels were detected in 2023, Laird said they don't have a "great" answer, but knowing that 2023 was the worst wildfire year on record in the N.W.T. gives them an idea.
"So that's the only common factor that we're aware of that matches the timeline of the lead levels that we saw increase and then come back down," he said.
However, Giant Mine has air monitoring equipment, but it didn't register any lead in the air during the fires. Laird said he doesn't know why, but that's a question researchers will explore.
He said they're also looking into where the lead could be coming from.
He said the youth taking part in the initial study were filling out questionnaires about the neighbourhoods they live in, the amount of time they spend on the land and the types of lakes that they've been visiting.
"So we've been combing through the data to try to find all of the associations between the levels in the kids' samples and their urine," Laird said.
"And so we'll have more of those results coming back to the community in the very near future that will hopefully be able to shed more light on those patterns."
Some test subjects attend William McDonald school
The test results come as lead levels at William McDonald Middle School in Yellowknife were recently found to be above Health Canada guidelines. In one test, levels were more than 100 times Health Canada's recommended amount.
Some of the test subjects in the Health Effects Monitoring Program are students who attended that school.
Laird said the latest results of his team's research are good news for those families as they showed the lead levels decreased in those students.
"So that does offer at least some reassurance, especially knowing that for all of those kids as well that had done that retesting, the levels in blood were ... below the [CDC] action level," he said.
Laird said the testing wasn't conducted on any adults, so it wouldn't take into account teachers at the school.
For people concerned about lead exposure, Laird says people in older homes can run their taps in the morning for about 60 seconds before drinking tap water.
He said having good nutrition can also help.
"Because a healthy diet, rich in calcium and iron, can help the body actually absorb less lead," Laird said.
Interview by Hilary Bird