In the aftermath of the Fort McMurray wildfire, U of T researchers look for toxins

This summer, postdoctoral researcher Lukas Kohl and undergraduate student Cynthia Jing will be vacuuming strangers’ homes in northern Alberta. But they’re not there to clean – they are looking for evidence of long-term human health impacts arising from last summer’s devastating wildfire.

That fire, which raged through northern Alberta one year ago, is already estimated to be the most costly natural disaster in Canada’s history, destroying approximately 2,400 homes and forcing the evacuation of nearly 90,000 people. But the ash left behind by the fire can continue to affect people’s health long after the flames have gone out, says Assistant Professor Arthur Chan, the principal investigator on the project.

“Smoke and ash can contain a large number of different compounds, including organic compounds, heavy metals, black carbon and more,” says Chan. “Some of these are suspected to be carcinogens or are linked to other negative health outcomes.”

Postdoctoral researcher Lukas Kohl and undergraduate student Cynthia Jing will sample homes in northern Alberta for ash left over from last summer’s wildfire (photo by Tyler Irving)

Chan and his team use advanced analytical chemistry techniques to tease apart all the different components of the complex chemical mixtures, including fire ash. They can detect everything from heavy metals such as lead, a potential neurotoxin, to organic chemicals such as polycyclic aromatic hydrocarbons (PAHs), which have been associated with cancer.

“Of course, our hope is that we won’t find anything,” says Chan. “But if we do, we can inform people of their risk and suggest adjustments to their cleaning habits. We want to understand the impacts before people start to suffer from them and provide guidelines to minimize exposure.”

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The team plans to collect house dust from dwellings in Fort McMurray, Alta. and other communities affected by the wildfire in the initiative – called Fire Ash Characterization and Evaluation of Toxicity (FACET). While much of the outdoor ash has been either shipped away from town or immobilized by spraying it with a glue-like substance known as tackifier, ash that has found its way into homes is a different story.

“This is the ash that is closest to people’s bodies and because we spend most of our time indoors, it would have the biggest impact on people’s health,” says Kohl. “Indoor pollution is not well understood so in a way this is a new perspective on forest fires.”

Dust collected using a wet, disposable cloth can be tested in the lab to see if it contains evidence of fire ash and/or elevated levels of toxic substances (photo by Tyler Irving)

Kohl and Jing will use a modified vacuum cleaner that collects dust in two small vials in the head of the device, before it has reached the mechanical components. They can also take samples by wiping surfaces with a wet, disposable cloth.

“We want to make sure we sample a variety of locations within the house,” says Kohl. “For example, we want to have one space that people clean often, like a living room, and one space that is not frequented, like an attic, where it is most likely we will find old dust that contains a lot of fire ashes.”

Initially, the team was concerned about the challenge of arranging house visits.

“When we’re sitting in Toronto, it can be hard to reach out to people who live hundreds of kilometres away,” says Kohl. But the response so far has been very positive.

“We have reached out to Facebook groups used by people in Fort McMurray, as well as local media,” says Jing. “Within two days, we already had more than 60 interested people contacting us about the study.”

The team plans to make three visits for each home – one in the summer, one in the fall and one in the winter ­– in order to minimize anomalies and compare any changes in hazard levels over time.