The blue-green algae bloom at Lost Creek Lake appears to be dissipating and the public-health advisory against water contact there could be lifted by the weekend, just in time for the busy Fourth of July weekend.
Water sampled last week showed that the cyanobacteria levels that were 32 times above state public-health standards had all but dissipated at Jackson County's largest and most popular reservoir, according to the U.S. Army Corps of Engineers.
Now Corps officials are hoping for similar results on toxicology tests that are expected by Friday, allowing a review by public-health officials before the voluntary advisory postings get removed.
"It's certainly my desire to have it lifted by this weekend, if the toxicology tests come back negative," says Jim Buck, the Corps' Rogue Basin project manager.
"The lake looks substantially better," Buck says.
Outbreaks of cyanobacteria, typically a strain called Anabaena flos-aquae, have been the bane of visitors to Lost Creek Lake, where twice-annual blooms and the subsequent advisories have been commonplace since the Oregon Health Authority began issuing advisories in the early 2000s.
The current advisory was issued June 3 and was the first of the summer algae-bloom season in Oregon, according to the OHA.
Anabaena flos-aquae can produce potentially dangerous toxins, particularly when the bloom dies off. But not all blooms become toxic.
During advisories, people and pets are warned to avoid water contact, but compliance is voluntary. Anglers are encouraged to practice catch-and-release fishing during advisories.
Toxins cannot be filtered by standard camp filters or by boiling the water. In-home filtering systems cannot cleanse the water, though public treatment plants can reduce algae toxins through filtration and disinfection.
Boating and fishing are considered safe so long as boat speeds do not create excessive water spray, according to health officials.
Exposure to toxins can produce numbness, tingling and dizziness that can lead to difficulty breathing or heart problems that require immediate medical attention. Symptoms of skin irritation, weakness, diarrhea, nausea, cramps and fainting should also receive medical attention if they persist or worsen.
Children and pets are at increased risk for exposure because of their size and level of activity.
No confirmed human illnesses have been tied directly to an algae outbreak in Oregon. However, at least four dogs have died in recent years from toxins in water near the Umpqua River near Elkton.
— Mark Freeman