Health alerts for toxic blue-green algae continue to be in effect at Merritt Reservoir in Cherry County, Kirkman’s Cove near Humboldt, and Willow Creek Lake near Pierce. Alerts have ended at Swan Creek Lake 5A near Tobias, and Red Willow Reservoir near McCook.

Samples taken earlier this week at Willow Creek were above the state’s health alert threshold of 20 parts per billion (ppb) of total Microcystins (a toxin released by certain strains of blue-green algae.) Although levels were below the threshold at Merritt Reservoir and Kirkman’s Cove this week, they will continue to be on alert due to high readings from samples taken at the two lakes the previous week. Lakes that are on health alert must have two consecutive weeks of readings below the threshold before the alert is discontinued.

When a health alert is issued, signs are posted to advise the public to use caution, and designated swimming beaches are closed during the alert. Recreational boating and fishing are permitted, but the public is advised to avoid activities that could involve accidental ingestion of water and to avoid full immersion in water. People can still use the public areas for camping, picnics and other outdoor activities.

The final weekly toxic algae sampling for 2010 will be collected at 46 public lakes early next week. The toxic health alert program runs during the recreation season (May 1 through September 30), so any remaining health alerts will end on Oct. 1. Final sampling results will be posted on NDEQ’s web site, https://dee.nebraska.gov/home, on Thursday afternoon, Sept. 30. Toxic algae sampling will resume in May, 2011 and will continue until the end of September, 2011.

The state reminds people that even though the recreation season is ending, they should continue to be aware of signs of blue-green algae if they visit Nebraska lakes. Toxic strains of blue-green algae can have a thickness similar to motor oil and often looks like thick paint in the water. The color can be neon green, pea green, blue-green or reddish-brown. Algae blooms usually accumulate near the shoreline where pets and toddlers have easy access and the water is shallow and more stagnant. It is important to keep a watchful eye on children and pets so that they do not enter the water.

(For more information about potential health effects of toxic blue-green algae, what to look for, and steps to avoid exposure, please refer to the Toxic Algae Fact Sheet.)