The wildfire season of 2023 in Canada was the most destructive ever recorded, with a new study suggesting that the impact was unprecedented. Four wildfires in mine-impacted areas around Yellowknife, Northwest Territories potentially contributed up to half of the arsenic emitted globally by wildfires each year. Led by researchers at the University of Waterloo and Nipissing University, the study calculated the amount of arsenic stored in high-risk wildfire areas around Yellowknife over the past five decades. The team estimates that the 2023 wildfires released between 69 and 183 tonnes of arsenic, a potent toxin associated with various health issues.
Arsenic can be transformed by wildfires and released into the environment from soils that typically sequester it. As climate change is expected to increase the frequency and severity of wildfires, regions where annual wildfires intersect with past or present mining and smelting operations could face a major risk of releasing stored toxins back into the environment. Dr. Owen Sutton, a postdoctoral fellow at the University of Waterloo, highlights that Yellowknife is not unique in its accumulation of arsenic due to decades of mining. Canada has many industrially contaminated sites that are vulnerable to wildfires, posing a significant threat to human and environmental health.
The amount of arsenic released by wildfires depends on factors such as fire temperature, burn depth, and soil type. The researchers emphasize the need for collaborative investigation by wildfire scientists, chemists, environmental scientists, and policy experts to address this issue. Integrating diverse fire management techniques, including Indigenous fire stewardship, may help mitigate emerging risks to human and environmental health. Dr. Colin McCarter, a professor at Nipissing University and Canada Research Chair in Climate and Environmental Change, stresses the urgency of addressing this issue to protect communities and ecosystems.
The researchers found that arsenic emissions from wetlands were particularly concerning due to their ability to store contaminants compared to forests. Moving forward, they plan to continue quantifying the amount of toxins stored by northern peatlands and study the potential release of other metals from these landscapes. Dr. James Waddington from McMaster University also contributed to the study. The research, titled “Globally-significant arsenic release by wildfires in a mining-impacted boreal landscape,” was published in Environmental Research Letters.
Overall, the study highlights the significant impact of wildfires in mine-impacted areas on releasing arsenic and other toxins into the environment. With the increasing frequency and severity of wildfires expected due to climate change, the risks of releasing stored contaminants into the environment are also likely to rise. Collaborative efforts among various experts and the integration of diverse fire management techniques are essential in mitigating these risks and protecting both human health and the environment. Continued research on the release of toxins from peatlands and other landscapes will provide valuable insights into addressing this issue in the future.