January 10, 2020
The Oregon Health Authority has lifted the recreational use health advisories for Tenmile Lake in Coos County.
Water monitoring has confirmed that the level of cyanotoxins (harmful algae toxins) in Tenmile Lake are below recreational guideline values for human exposure. However, officials advise recreational visitors to be alert to signs of cyanobacterial (harmful algae) blooms, because blooms can develop and disappear on any lake through the season. Only a fraction of Oregon’s lakes and streams are monitored for cyanobacterial blooms.
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. If you see these signs 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.
Homeowners who pull water directly from the lake through private intakes should be aware that the levels of cyanotoxins in the water where sampling occurred are still above the drinking water values for children 5 and younger. Levels continue to be above OHA’s informational guideline values for dogs.
No additional sampling is planned or expected by the county or the Tenmile Lakes Basin Partnership.
For health information or to report an illness, contact the Oregon Health Authority at 971-673-0482.
Cyanobacteria (Harmful Algae) Blooms