With summer in full swing, the Oregon Health Authority (OHA) is monitoring water quality and reminds people heading to the state’s lakes, rivers and reservoirs to be on the look-out for potentially toxic cyanobacteria harmful algae blooms. Cyanobacteria are beneficial bacteria found in most fresh water worldwide and under the right conditions—warm weather, sunlight, water temperature, nutrients and water chemistry—they can multiply into blooms.
Some species of cyanobacteria live in the water or float on the top of the water surface. Other cyanobacteria mats anchor themselves to the bottom of a water body, live in the sediment or grow on rocks or aquatic plants, and can release toxins into clear water.
Some blooms produce cyanotoxins that make people and animals sick. They can make the water look green or other colors and form scum-like masses or mats in water or on shore where they can be wet or dry.
“As the warmer weather draws us to Oregon’s lakes and rivers, people—especially small children—and pets should avoid areas where there are signs of a cyanobacteria bloom, the water is foamy, scummy, thick like paint, pea-green or blue-green, or if thick green or brownish-red mats are visible, or bright green clumps are suspended in the water or along the shore,” said Linda Novitski, Ph.D., a recreational waters specialist in OHA’s Environmental Public Health Section.
Although cyanotoxins are not known to be absorbed through the skin, people with sensitive skin can develop a red, raised 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 minutes to hours of exposure to cyanotoxins by drinking the water. Illness can also occur when dogs lick their fur or eat the toxins from floating mats or dried crust along the shore. If, after swimming in a lake or stream, a dog exhibits symptoms such as diarrhea, vomiting, breathing problems, difficulty walking or standing or loss of appetite, owners should seek veterinary care as soon as possible.
Open recreational areas where blooms are identified can still be enjoyed for activities such as camping, hiking, biking, picnicking and bird watching. Visitors can also enjoy water activities such as canoeing, boating and fishing, as long as boat speeds do not create excessive water spray and fish are cleaned appropriately.
Only a fraction of water bodies in Oregon are monitored for blooms and toxins, so it’s important for people to become familiar with the signs of a bloom. Those who are unsure should follow OHA’s guidance of “When in doubt, stay out.” For more information, visit OHA’s CyanoHAB website, healthoregon.org/hab, or call 971.673.0440.