Toxic Algae Bloom Closes Green Lake – Update November 1

On October 2, 2012 Seattle Park Department closed Green Lake to wading, swimming, and wet water boating activities. The closure was in response to test results that show a high level of microcystin, a toxin produced by a cyanobacteria more commonly known as bluegreen algae. A water sample collected on September 28th showed the toxin level exceeded the guidance levels for recreational waters.

Closure Remains in Effect at This Time

The most recent sample collected October 22 exceeded the guidance level. As a result the closure remains in effect. Additional samples will be collected and analyzed by King County this week and next to determine when the level of toxin has dropped below the guidance level.

King County Department of Health and the Seattle Park Department will make the determination to remove the closure notices when the test results show the toxin level is below the guidance levels.

Test results for many lakes including Green Lake are posted at nwtoxicalgae.org. Go to the website and search for Green Lake to find Green Lake test results. If you have questions or comments or observations you can email Garet Munger at garetpeter@comcast.net.

We urge you to join with other Friends of Green Lake at our monthly meetings as we learn more about algae and the lake. See meeting notices elsewhere on this page.

In the meantime it is good cautionary practice to keep dogs from entering and drinking the lake water. Be especially careful where there is a bright green scum on the water.

PLEASE NOTE: It is best at this time NOT to take a sample yourself because the algae could be toxic.
Photo by Gayle Garman