How forest fire smoke in the Thunder Bay area is harming waterways

As Canada continues to battle relentless forest fires, Thunder Bay's blue skies are sometimes turning grey with smoke from fires, both near and far.

While the smoky air has created serious health risks for vulnerable groups, it is also putting the region's already at-risk waterways in jeopardy.

According to Robert Stewart, an associate professor in the geography department at Lakehead University, the majority of the area's rivers are negatively affected by urbanization and storm water, but must now deal with the side effects of climate change.

Stewart said particles in the air are essential to forming raindrops or creating different kinds of air masses and weather systems. But they're likely being imbalanced by forest fire smoke and heat.

"[The imbalanced particles] carry natural particulates and other components that can land back down in these water systems, particularly in high levels," said Stewart.

Another range of contaminants and toxins from burned down human landscapes can easily drop into the waterways and stay for a long time. Stewart said these kinds of contaminants are called "forever chemicals" and can last for long periods of time in aquatic ecosystems, resulting in significant impacts.

"Things like fire retardants or construction material have chemicals that we put together in them that, when broken down, are ending up in water bodies," said Stewart.

"We're finally noticing them in high enough concentrations to be of concern. And there's no way of just reversing that. And it's those types of problems that water management is really concerned with and focusing a lot on, because we know we're putting out and regulating through point sources."

In addition, Stewart said smoky skies can prevent the heat transfer from radiation from sunlight entering waterways.

"There is a level of shortwave radiation [energy that originates from the sun] that's being impacted by smoke in the air," said Stewart. "There's probably a level of longwave radiation [energy that originates from the Earth] coming from the Earth and from water bodies that get trapped, perhaps in the air, that has more particulate matter in it. And that could cause warming."

While Stewart said he thinks there needs to be a significant change in the air quality for there to be any significant changes to water temperatures, he said a body of water's evaporation is something to be mindful of.

"The evaporation level of a lake or river is important to its water levels and its homeostasis [when an organism remains stable while also adjusting to surrounding conditions], and that could be impacted, obviously, from air temperature changes, as well as anything blocking the movement of short and longwave radiation, which of course is the root of climate change."

Smoke adds fuel to fire of already 'disturbed' system

Stewart said the effects of forest fire smoke add another layer of impact to an already "disturbed" system. He said the repercussions make understanding the root source of contaminants in waterways more of a challenge.

"How to address the problem and how to separate the different problems, like dealing with contaminants from an urban environment that are now being added from contaminants [and] smoke, blurs our ability to know where these contaminants are coming from, and what their impact is from different sources.

"So I would say it would be more of that level. In a fluvial system [rivers and streams] or an aquatic ecosystem [lakes, oceans, wetlands, etc.], where things are coming from gets more challenging the more we identify new problems that are going to change the balance from these systems." 

Stewart admitted the added damage to waterways from smoke and forest fires worries him.

"It does concern me. Certainly more forest fires from the norm concern me, and I know that it has a very intimate relationship with rivers and lakes and the forest ecosystem."

Water a source of life

Forest fires can cause serious and long-term effects on water supplies. In Nova Scotia, Halifax-area residents returning to their homes after a forest fire evacuation were told to not drink well water because damaged fuel tanks or ash from burned materials were absorbed into the soil and entering wells.

According to Monica Emelko, the Canada Research Chair in water science, technology and policy at the University of Waterloo, forest fire contaminants can strain water treatment infrastructure and supply.

For Thunder Bay, while the forever chemicals cause damage to waterways, Stewart said they don't currently have any negative outcomes on the region's drinking water.

"Luckily in northern Ontario, we get a lot of water," said Stewart. "So dilution seems to help us a lot here, but that can be affected through changes in the future, obviously, if we have less air moisture from heat and warming. Then we're going to have subsequent changes in how much surface water there is."

Stewart said since Lake Superior is so large and cold, Thunder Bay can still get high quality drinking water from it, despite how much it has been affected by pollution.

"Treatment is more of a precautionary manner when the water is in pipes to make sure it stays clean. And the city of Thunder Bay has an amazing monitoring of that water quality. So I think, from the perspective of knowing something's coming into the water supply and doing something about it in the sense of reaction, we're good at that."

Stewart added that society is now at a point where it's recognizing the value of protecting water and keeping it clean.

"We are reaching a new realm where water is something that can't just be studied, monitored and figured out. It is ultimately the source of sustenance for us that we really need to protect more so than use as a resource. And like I said, I think society is going to go back more and more to that traditional value of water really being the source of life, and protecting it."