Oregon Public Health officials are urging awareness about algae bloom season and suggest that Memorial Day weekend may bring more people in contact with harmful blooms.
“As folks head out for the holiday weekend and throughout the summer, we want people who use Oregon’s lakes, reservoirs and other fresh waters for recreation to enjoy these areas, but to take precautions if they see an algae bloom,” said Jennifer Ketterman, coordinator of the Oregon Public Health Harmful Algae Bloom Surveillance (HABS) program. “We advise people to avoid swallowing or inhaling water droplets from algae-affected water and to avoid skin contact.”
Last year Oregon Public Health issued 21 health advisories due to cyanobacteria, or blue-green algae, because of the potential for exposure to toxins. This was an increase over 2008, when 14 health advisories for harmful algae blooms were issued. Also, in 2009 Oregon recorded its first confirmed dog death due to algae toxin in water near the confluence of Elk Creek and the Umpqua River in Douglas County.
Not all algae are dangerous, but some species can produce toxins that pose a health threat to people and animals that come in contact with them, according to Ketterman.
Skin irritation or rash is the most commonly reported health effect. Symptoms could also include diarrhea, cramps, vomiting, fainting, numbness, dizziness and paralysis.
Children and pets are most vulnerable, and dogs can fall ill almost immediately after ingesting waters affected by toxic algae.
The HABS program relies on agencies that manage water bodies — such as the U.S. Army Corps of Engineers and U.S. Forest Service, along with other federal and state agencies — to alert it when a potentially toxic bloom has been detected. When water tests confirm that a toxic species is present in a lake at a magnitude that constitutes a health threat, Oregon Public Health issues a health advisory and various community and state partners post signs at the affected water body.
“Because only a fraction of Oregon’s waters are routinely monitored for algae blooms, we advise people to be watchful when they are exploring the great outdoors,” Ketterman said. “If waters are scummy or cloudy and blue-green, bright green, white or brownish-colored, treat them as potentially contaminated and stay out. It is especially important to keep children and pets from going into questionable water.”
Ketterman reminds people that if they arrive at a lake and find an algae bloom in progress, they can still enjoy activities that don’t involve water contact, such as camping, picnicking, hiking and bird watching.
Blooms are most prevalent during the summer months, but they can occur any time of the year. In 2009, Oregon Public Health issued the first algae bloom health advisory of the season on May 21 and lifted the final advisory on Nov. 30.
The HABS program is funded through a federal grant from the Centers for Disease Control and Prevention. Program objectives include collecting reports of harmful algae bloom occurrences, as well as human and animal sickness; notifying the public when a harmful bloom is underway; and increasing public awareness through education and outreach activities.
More information on harmful algae blooms — including what to look for, listing of previous locations with algae blooms and information about how to stay informed — can be found at www.healthoregon.org/hab or by calling 971-673-0440.