As Oregon temperatures reach triple digits, the Oregon Health Authority is warning people not to jump into rivers and lakes with toxic algae blooms.
Cyanobacteria are blooming in nine Oregon bodies of water, from Hells Canyon Reservoir to Upper Klamath Lake and the South Umpqua River.
In Portland, the Oregon Health Authority has placed advisories on the Willamette River near Ross Island Lagoo and Riverplace Marina. On Monday, it also extended an advisory at Willamette Cove downstream to near Cathedral Park. Essentially, the advisory covers much of downtown.
Cyanobacteria are found in fresh and salt water all over the world. The bacteria can be beneficial by producing oxygen, but in warm weather, low water flows can lead to blooms that produce large amounts of cyanotoxins.
Kylah Peterson cools off on the Willamette River on Monday, Aug. 14, 2023. The Oregon Health Authority has issued several warnings for toxic algae blooms in waterways across the state as temperatures reached into the triple digits.
Kristian Foden-Vencil / OPB
Kylah Peterson, a 26-year-old Portland resident, doesn’t have air conditioning, so she uses fans and window curtains to stay cool. On Monday, she visited Sellwood Park to dip her feet in the Willamette River, not far from one advisory area.
“It’s definitely something to be concerned about,” Peterson said. “But I’m being very cautious and just keeping my feet in.”
As a veterinary assistant, Peterson was also keeping an eye out for dogs running in and out of the river. Dogs and other animals, including cats, horses, birds and humans, are susceptible to cyanotoxins. They can enter the body when contaminated water is ingested. The toxins can cause symptoms ranging from skin irritation to liver and kidney damage. Symptoms generally begin within 24 hours and last 72 hours. For pets, they can sometimes be fatal.
The number of algae blooms in Oregon has increased over the last decade. Peterson blamed the rise in temperatures resulting from human-caused climate change.
“It kind of makes me sad because I’ve lived here for a while and these heat waves weren’t what I grew up with. It does seem like climate change is happening,” she said. “I kind of miss how it was, but we’ve got to move forward and this is how it is now.”
Willie Levenson, head of the Human Access Project, a nonprofit dedicated to getting more people to swim in the Willamette River, agrees that climate change has increased local algae blooms. But, he said, things can be done to reduce the number of blooms.
For example, Ross Island Lagoon sits on an island. It’s where Ross Island Sand and Gravel have dug aggregate for concrete for 100 years. As a result, there’s a pool 130 feet deep, where water from the Willamette River backwaters sits and warms, causing an algae bloom.
Levenson and his group are trying to secure federal funding so they can pay to dig a channel that would move more river water through the lagoon, cooling the water and reducing algae blooms.
“The harmful algae bloom forms inside of the lagoon and then winds and tides blow it out into the channel. Then it migrates into the mainstem of the river,” Levenson said.
Levenson said the Willamette River should be viewed as a natural cooling station that people need when temperatures rise, rather than a potential threat to their health.
For anyone visiting the water in this week’s heat, they should take cyanobacteria seriously, he said.
“Harmful algae bloom is a very serious issue. I mean it’s probably the biggest issue in Portland that people aren’t aware of.”
When he swims, which is about four times a week, Levenson makes sure the water is moving relatively quickly, and that there are no green flecks floating on the surface.