It’s blue and green, floats in water and can be toxic to humans and pets, and its presence in the South Umpqua River is routine enough that a permanent health advisory is in effect.
Douglas County’s summer was hot and dry — until late September and record-setting rain fell on the final two full days of summer. Nevertheless, for the second straight year, the Oregon Health Authority didn’t issue a single advisory in the county warning people about blue-green algae blooms.
Last week, officials issued a warning for Tenmile Lake, eight miles south of Reedsport in Coos County. It was the 11th advisory issued this year statewide, compared to nine last year. Before then, the state was issuing about two dozen warnings a year.
The reduction was due to a change in state policies, rather than a change in water conditions.
Before 2012, the public was notified anytime a bloom was identified. Now, the state issues a warning only when it determines a potential health risk exists. The change has lowered the number of advisories. For example, a bloom discovered at Diamond Lake this summer had a toxin level below the threshold for an advisory.
Under the old rules, 20 advisories would have been issued in 2012, according to the health authority.
Rebecca Hillwig, coordinator of the state’s algae bloom program, said algae may have been connected to the death of a dog that came in contact this summer with the Umpqua River near Cow Creek.
“It sounds like it was,” she said. “The problem is the symptoms are very similar to other things like heat stroke and food poisoning.”
A string of dog deaths in 2009 linked to the algae floating in the waterway prompted an indefinite advisory on the South Umpqua River, the only river in the state with a permanent warning.
“We worked with Douglas County to actually produce 60 permanent advisory signs to be posted along the river,” Hillwig said.
She described the river as unusual because lava rock along the banks creates a place for water to pool and become stagnant, creating ideal breeding ground for the bacteria.
Hillwig said only a fraction of Oregon’s water bodies are being monitored. Priority for monitoring is typically put on water in more populated areas, where the risk exposure to humans is higher.
“There are just so many, and there are not enough resources to do all of them,” she said.
“I am sure there are a ton of water bodies out there with blooms that we don’t hear about or people aren’t really monitoring,” Hillwig said. “Even if there isn’t an advisory on a lake, it doesn’t mean that it’s safe for your pets. Advisories are based on human levels.”
Health officials say these ancient forms of bacteria are always present in the water and are generally unnoticeable. But when weather, sunlight and nutrients are optimal, the bacteria multiples into what is called a “bloom,” which often takes on the appearance of algae. The name “blue-green” comes from the color that blooms oftentimes have. Some blue-green algae have the potential to produce toxins, but not always at levels that are harmful.
Exposure to toxins can produce symptoms of numbness, tingling and dizziness that can lead to difficulty breathing or heart problems, and require immediate medical attention. Symptoms of skin irritation, weakness, diarrhea, nausea, cramps and fainting should also receive medical attention if they persist or worsen, health officials say. Children and pets are at increased risk for exposure because of their size and level of activity.
•You can reach reporter Christina George at 541-957-4202 or at firstname.lastname@example.org.