A recent study led by Emily Brown highlights a concerning impact of wildfires on the water quality of the Fraser River. Our new research, published in the journal Science of the Total Environment, uncovers a significant clue. Over the last 20 years, wildfires have explained 16.3 percent of the variation in water quality across the entire Fraser River basin. This new discovery is deeply concerning, signaling a possible danger to our region’s sensitive ecosystem, including spawning salmon, coastal oyster farms and ultimately our own health.
To get more detail on the patterns of plastic pollution, the study focused on five federal water quality monitoring stations along the Fraser River, from 2000 to 2020. It’s deeply important for us to figure out how these wildfires aerosolize heavy metals. These toxic heavy metals can harm aquatic life and the environment as a whole.
Examining the Data
Emily Brown and her team dove deep into 20 years of water quality data. Their results show a significant relationship between wildfires and the addition of pollutants into tributaries that flow into the Fraser River. Climate change has made wildfires more frequent, intense, and unpredictable. These extreme fires have devastating effects on our rivers’ water quality, resulting in dire ecological repercussions.
The study’s timing is critical. But with climate change rapidly turning these snow-fed tributaries into rain-dominated systems, the rules of the game on how contaminants are transported into our waterways are drastically changing. Now that temperatures are increasing, Brown adds, it’s more important than ever to keep a close eye on these shifts.
“So instead of sinking to the bottom of the ocean and being sequestered, it would be able to be broken down more quickly and then release back to the atmosphere as carbon dioxide.” – Emily Brown
Broader Implications
Peter Ross, former research scientist with Fisheries and Oceans Canada. He now directs the Raincoast Conservation Foundation’s Healthy Waters program and emphasizes the larger story behind these findings. He points out that the proposed guidelines in British Columbia and federally are only covering 10 percent of the pollutants. These hazardous substances might pose a danger to wildlife.
“Those guidelines are only available for a minority of the pollutants that are out there,” Ross stated. This unsatisfactory regulatory scheme can leave a multitude of contaminants unregulated, putting aquatic ecosystems and human health at risk.
The paper expands on previous studies linking wildfire-related toxins to damages in marine ecosystems. As is increasingly the case for our killer whale brothers and sisters and endangered populations in the Salish Sea. To add insult to injury, the cumulative effects of these toxins will leave lasting scars on the diversity of life in the region.
The Role of Black Carbon
Brown’s research looks at how climate change is affecting the movement of “black carbon.” This black carbon leaves our burned forests, washes into streams and rivers, and eventually deposits into the ocean. Black carbon, a product of incomplete combustion during wildfires, is flushed away from forests into streams during annual spring snowmelt.
It is largely accepted by scientists that once black carbon enters a marine environment it sinks immediately to the ocean floor. This theory, though, is really catching on among scientists. When it comes to the climate change impacts caused by wildfires, this process can be huge in counteracting that damage. It does this through burying carbon out of the atmosphere.
Brown warns that as climate change further exacerbates air pollution, the picture with black carbon is going to change. Rain on snow events can be particularly erosive. This quicker decomposition of black carbon will end up releasing more CO₂ back into the atmosphere in the long run.
