Odell Lake in Klamath County is under a health advisory after tests found elevated levels of toxins produced by cyanobacteria, the latest reminder of a recurring summer hazard in Oregon’s lakes and reservoirs.
Harmful algal blooms thrive in warm, slow-moving water and can pose health risks to people and pets. But health officials say an advisory doesn’t necessarily mean an entire lake is off-limits, and knowing what to look for can help people recreate safely.
Cyanobacteria can produce toxins that can make people sick if contaminated water is swallowed. Contact with the water can also cause skin rashes.
Klamath County Public Health says people should avoid water that smells bad, looks discolored or has afoam or scum on the surface. Cyanobacteria often appear bright green or blue.
The toxic blooms can be fatal to dogs, and health officials encourage people to keep pets away from these toxic areas.
Not all waterways carry the same risk. Valaree Lane with Klamath County Public Health says momving bodies of water are less likely to develop blooms.
Klamath Lake is a “body of water that doesn't have a lot of movement in it, so that allows for that algae to be present, and also for it to overpopulate and bloom,” Lane said. “Our streams, our creeks, our rivers are all moving water, which allows for it to be cleaner and a better fishing resource.”
Lane said even when a harmful bloom is present in Klamath Lake, some areas can still be used for recreation.
“We have an abundance of opportunities to recreate in the water, so would never encourage people to stay away, but to be thoughtful about where they are going,” Lane said.
Information about affect waterways found can be found on the Oregon Health Authority website.
Cyanobacteria naturally grow during hot summer months. Although the organisms have existed for billions of years, the Environmental Protection Agency says climate change can contribute to more frequent or intense harmful algal blooms as temperatures rise and conditions favorable to their growth last longer.
