July 31, 2018
Reduced cyanobacteria and cyanotoxin levels confirmed
The Oregon Health Authority (OHA) has lifted the recreational use health advisory issued June 25 for Upper Klamath Lake, located off Oregon Route 140, 15 miles west of Klamath Falls in Klamath County.
Water monitoring has confirmed that the level of cyanotoxins (harmful algae toxins) in the reservoir are below recreational guideline values for human exposure. However, the level of microcystin in Howard Bay of Upper Klamath Lake remains well above the OHA guideline value for dogs, so health officials recommend keeping pets out of this area.
Oregon Health officials advise recreational visitors to always be alert to signs of cyanobacterial (harmful algae) blooms in all Oregon waters, because blooms can develop and disappear throughout the season. Only a fraction of the many lakes and waterways in Oregon are monitored for cyanobacteria by state, federal and local agencies; therefore, you are your own best advocate when it comes to keeping you and your family safe while recreating.
People and especially small children and pets should avoid recreating in areas where the water is foamy, scummy, thick like paint, pea-green, blue-green or brownish-red in color, if a thick mat of blue-green algae is visible in the water, or bright green cells are suspended in the water column. If you observe these signs in the water you are encouraged to avoid activities that cause you to swallow water or inhale droplets, such as swimming or high-speed water activities.
It’s possible cyanotoxins can still exist in clear water. Sometimes, cyanobacteria can move into another area, making water that once looked foamy, scummy or discolored now look clear. However, when a bloom dies elsewhere in the water body, it can release toxins that may reach into the clear water. There also are species of cyanobacteria that anchor themselves at the bottom of a water body, live in the sediment, or can grow on aquatic plants and release toxins into clear water near the surface.
For recreational health information, to report human or pet illnesses due to blooms or cyanotoxins in recreational waters, contact the Oregon Health Authority at 971-673-0440.
For information about recreational advisories issued or lifted for the season, contact the Oregon Public Health toll-free information line at 877-290-6767 or visit the Harmful Algae Blooms website and select "Algae Bloom Advisories."
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