May 18, 2020

Be aware of cyanobacteria (harmful algae) blooms this summer

Increasing temperatures create potential for cyanotoxins in water

PORTLAND, Ore. — As summer approaches and communities around the state begin reopening amid the COVID-19 outbreak, Oregon Health Authority (OHA) reminds people heading outdoors to be on the lookout for toxin-producing cyanobacteria blooms when recreating in Oregon lakes, rivers and reservoirs.

Because cyanobacteria blooms are naturally occurring worldwide, they can form in any water body. Many blooms are harmless, but under the right conditions — when weather, sunlight, water temperature, nutrients and water chemistry are ideal — they can produce cyanotoxins that make people and animals sick.

Exposure to cyanotoxins occurs when water is swallowed while swimming, or when water droplets are inhaled during high-speed activities such as water skiing or wakeboarding. Symptoms of exposure to cyanotoxins include diarrhea, cramps, vomiting, numbness, dizziness and fainting. Although cyanotoxins are not absorbed through the skin, people with sensitive skin can develop a rash when wading, playing, or swimming in or around a bloom.

Children and pets are particularly sensitive to illness because of their size and activity levels. Dogs can get extremely ill and even die within hours of exposure to cyanotoxins by drinking the water, licking their fur, or eating the toxins from floating mats or dried crust along the shore.

Only a fraction of Oregon’s fresh water is monitored for cyanotoxins. This year, with safety concerns related to COVID-19, OHA expects even less sampling of affected water bodies. For this reason, it will be even more important, as recreational areas open and Oregonians begin to recreate, to understand your surroundings before you or your pet take the plunge.

OHA recommends that everyone stay out of water that looks foamy, scummy, thick like paint and pea-green, blue-green, or brownish-red in color. If you are unsure, follow OHA’s guidance of “When in doubt, stay out.”

Open recreational areas where blooms are identified can still be enjoyed for activities such as camping, hiking, biking, picnicking and bird watching. By being aware of signs of a bloom and taking appropriate precautions to reduce or eliminate your exposure, you can also enjoy water activities such as canoeing, fishing, and boating, as long as speeds do not create excessive water spray.

To learn if an advisory has been issued or lifted for a specific water body, visit the Harmful Algae Bloom website or call the Oregon Public Health Division toll-free information line at 877-290-6767.

For health information or to report an illness, contact OHA at 971-673-0440. For campground or lake information, call the local management agency.

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