Study suggests increase in lead levels among Yellowknife youth

Preliminary results from a long-term health study suggest an increase in lead levels among Yellowknife children and youth over the past five years.

The Health Effects Monitoring Program was launched in 2017 to meet the requirements of an environmental assessment of the Giant Mine Remediation Project.

Five years later, researchers carried out a follow-up study on children and youth. The results of that follow-up work were shared at a community meeting in Yellowknife on Wednesday night.

The findings indicate that lead levels in biological samples taken from children aged three to 19 in Yellowknife increased between 2017-18 and 2023.

“It came as a surprise,” said Dr Laurie Chan, a professor at the University of Ottawa and Canada research chair in toxicology and environmental health.

“We were not expecting that because we didn’t see any significant differences between the other metals, like arsenic and cadmium, and so it stood out to be something that seems to be unusual.”

Chan said further research is needed to confirm those results, however, as urine is not a good indicator of lead. He added there is currently “no obvious answer” as to the potential cause of the elevated lead levels.

“Maybe it’s a false alarm,” he said.

“We don’t want to have any elevated level of lead in anyone because lead is not good in any amount.”

Chan said researchers plan to follow up with the roughly 38 participants whose urine samples showed higher lead levels and ask them to provide blood samples and answer lifestyle questions. He said they plan to publish further findings next year.

“Hopefully by doing more detailed investigations, we can find out why these youth have high levels of lead,” he said.

Chan said while researchers suspected participants could have been exposed to lead in the water or air, they have already ruled out those sources. He said there has been no change in lead concentrations in Yellowknife’s drinking water over the past decade and there was no increase in lead levels in the air in 2023.

“Originally, I suspected it could be related to the forest fire last year,” Chan said, saying he had since concluded that the fire “didn’t burn any buildings, it was all in the forest, so it didn’t cause any increase in lead in the air.”

The latest research findings are based on analysis of urine and toenail samples provided by hundreds of participants in Yellowknife in 2017-18 and 2023.

The study found that arsenic levels had slightly dropped among children and youth during that time. Researchers said cadmium levels had slightly increased but were still below the Canadian average.

Chan said, in general, cadmium levels increase with age and are high in youth who smoke or are exposed to second-hand smoke. He said researchers plan to also follow up with participants whose cadmium levels rose.

“The participants are five years older, so it’s kind-of natural to see higher levels,” he said, adding youth may have begun smoking as they grew older.

“Again, we will follow up and check and, of course, we advise kids not to smoke and lower their exposure.”

Roughly a third of participants return

Of the 408 children and youth who participated in the 2017-18 study, 142 returned for the 2023 study. An extra 122 participants were randomly selected in 2023.

Chan said the drop in returning participants may be explained by some people moving away from Yellowknife, while others were not interested in participating. The study required participants to have lived in the city for the past 12 months.

The recent results are part of a long-term health study monitoring arsenic and other metals of concern among residents in Yellowknife, Ndılǫ and Dettah.

The Health Effects Monitoring Program aims to determine whether residents in the Yellowknife area are exposed to higher levels of arsenic and other metals than other Canadians – exposure that could result from the Giant Mine remediation work.

The program also investigates the long-term relationship between arsenic and health outcomes.

Initial results from the study, released in 2019, indicated contaminant levels among Yellowknife area residents were comparable to those in other Canadians.

Further findings published in 2023 suggested arsenic exposure was not directly linked to diseases such as skin cancer among Yellowknife-area residents.

Chan said the latest results indicate the importance of the program, allowing researchers to pick up on changes in metal levels and follow up.