The 2023 wildfire season was the most destructive on record in Canada and a new study suggests the impact was unprecedented. It found that four of the year’s wildfires in mine-affected areas around Yellowknife, Northwest Territories, potentially contributed to half of the arsenic emitted annually by wildfires worldwide.
The work, led by researchers from the University of Waterloo and Nipissing University, is the first to calculate the amount of arsenic stored in areas at high risk of wildfires around Yellowknife. Looking at data from the past fifty years, the team estimates that the 2023 wildfires may have released between 69 and 183 tons of arsenic.
Arsenic, a powerful poison that the World Health Organization associates with diabetes, cardiovascular disease, several forms of cancer and infant mortality, can be metabolized by wildfires and released into the environment from the soil where it is normally stored.
Given that the frequency and severity of wildfires are expected to increase due to climate change, the researchers warn that in all regions of the world where annual wildfires intersect with past or current mining and smelting activities, future fires could pose a major risk form the release of stored fuel. toxins back into the environment.
“Yellowknife has a decades-long history of mining, which has led to an accumulation of arsenic in the surrounding landscape. However, Yellowknife is not unique in this regard; Canada has many industrially contaminated sites that are vulnerable to wildfires,” says Dr. Owen Sutton, a postdoctoral researcher at the Faculty of Environment in Waterloo.
The amount of arsenic released by forest fires depends on many factors, such as fire temperature, depth of combustion and soil type, and the combination of these variables.
“While our research has raised alarms on this issue, we will be the first to argue that there is an urgent need for collaborative research by wildfire scientists, chemists, environmental scientists and policy experts,” said Dr. Colin McCarter, professor in the department. of Geography from Nipissing University and Canada Research Chair in Climate and Environmental Change. “By integrating various fire management techniques, including indigenous fire management, we can hopefully mitigate these emerging risks to human and environmental health.”
The researchers found that arsenic emissions from wetlands were of most concern due to their tendency to store pollutants compared to forests. In the future, they will continue to quantify the amount of toxins stored in northern peatlands and study the potential emissions of other metals from those landscapes.
Dr. James Waddington, from McMaster University, also contributed to the work. “Globally significant arsenic emissions from forest fires in a mine-affected boreal landscape” appears in Environmental Investigation Letters.
