Wildfires mobilize chemicals in smoke with potential impacts to downwind communities and ecosystems. Although human exposure to smoke has been studied for years, recent evidence suggests that smoke can also have water quality impacts far downwind of the fire epicenter.
In a 2023 study, EPA researchers found that smoke contains extremely high levels of airborne nutrients, which, if deposited on the surfaces of lake and reservoirs, could stimulate algal blooms. These algal blooms can negatively affect drinking water through the production of cyanotoxins, while also impacting aquatic life.
A recently published subsequent study confirmed that the presence of wildfire smoke is indeed significantly correlated with downwind algal blooms. This work compared chlorophyll-a measurements from 2,000+ lakes across the contiguous United States, both before and after smoke events. Chlorophyll-a from algae increased significantly for lakes experiencing smoke events, particularly more dense smoke. Chlorophyll-a also increased for higher elevation and eutrophic lakes after exposure to wildfire smoke. Taken together, this evidence suggests nutrient mobilization from wildfire smoke, in potential combination with changes in light availability, are causing spikes in algal activity in downwind lakes. Because wildfire activity is increasing, these findings have implications for drinking water and recreational lakes across the United States, as well as for lake ecology, particularly in higher elevation systems with otherwise limited nutrient inputs.
Presenters
Nicole Olson, EPA Office of Applied Science and Environmental Solutions
Dr. Olson is a physical scientist in EPA’s Office of Applied Science and Environmental Solutions. She joined EPA in August 2021 where she got involved with wildfire research. She is particularly interested in investigating the link between wildfire nutrient emissions and harmful algal bloom formation. In addition, Nicole has worked on the atmospheric science chapters of the Integrated Science Assessments and projects investigating the health impacts of greenspaces and nature-based solutions. She completed her PhD in analytical chemistry at the University of Michigan, with work focusing on air quality and harmful algal bloom health impacts.
Irena Pavlovic, EPA Region 9
Irena is an environmental health scientist in EPA Region 9, based out of Los Angeles. She joined EPA in March 2023 and serves as the regional lead on wildfire and smoke issues as well as a Project Officer for air monitoring and analysis grants. She completed her Masters in environmental toxicology from Columbia University with a focus on fate and transport of emerging contaminants.
Moderators:
- Brenda Rashleigh, EPA Office of Applied Science and Environmental Solutions
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