Three southeast Nebraska lakes are currently under Health Alerts following the discovery of high levels of toxic blue-green algae, also known as Harmful Algal Blooms. The Nebraska Department of Environmental Quality (NDEQ) conducts weekly sampling of 50 public recreational lakes in the state from May 1 through September 30, posting the weekly results here. Levels are measured on Mondays and the results are posted on Fridays.

Algae blooms are large formations of certain strains of cyanobacteria that can cover the surface of a body of water.

UNL The toxic blue-green algae typically displays a characteristic blue-green color, but can sometimes be green, brown or red. Affected lakes usually have large surface growths of algae which can look like clumps, streaks, or scum, and the water will smell foul. You may also see unusual foam on the shore.

The algae produces a toxin called Microcystin which is harmful to humans and animals.

UNL Any concentration of Microcystin greater than 20 parts per billion in the water results in a Health Alert. The following three lakes are currently under Health Alerts. (Please note that the following photos are only representative of the lakes; they do not depict current toxic algae growth.)

Pawnee Lake, Lancaster County

TripAdvisor/navvets This lake near Lincoln tested at 34 ppb of Microcystin on June 19th. The sample taken on June 26th was down to 4.34 ppb, but the Health Alert will remain in effect until the lake tests below 20 ppb for two consecutive weeks.

Iron Horse Trail Lake, Pawnee County

Nemaha NRD A measurement of 21.77 ppb triggered the toxic algae Health Alert on June 19th, and the June 26th measurement was 32 ppb. Signs are posted at the park warning visitors of the health risk and advising the public to avoid ingesting or swimming/wading in the water.

Rockford Lake, Gage County

National Park Service This lake was first placed on Health Alert following its June 26th sample which measured at 21.24 ppb of Microcystin. The alert will remain in effect until Microcystin levels are below 20 ppb for at least two consecutive weeks.

Coming into contact with affected water can cause rashes and skin irritation; if the water is ingested it can cause stomach or intestinal distress. Be especially careful to keep pets, children, and people with compromised immune systems away from water with high Microcystin levels as they are more susceptible to its harmful effects.

UNL

The toxic blue-green algae typically displays a characteristic blue-green color, but can sometimes be green, brown or red. Affected lakes usually have large surface growths of algae which can look like clumps, streaks, or scum, and the water will smell foul. You may also see unusual foam on the shore.

Any concentration of Microcystin greater than 20 parts per billion in the water results in a Health Alert. The following three lakes are currently under Health Alerts. (Please note that the following photos are only representative of the lakes; they do not depict current toxic algae growth.)

TripAdvisor/navvets

This lake near Lincoln tested at 34 ppb of Microcystin on June 19th. The sample taken on June 26th was down to 4.34 ppb, but the Health Alert will remain in effect until the lake tests below 20 ppb for two consecutive weeks.

Nemaha NRD

A measurement of 21.77 ppb triggered the toxic algae Health Alert on June 19th, and the June 26th measurement was 32 ppb. Signs are posted at the park warning visitors of the health risk and advising the public to avoid ingesting or swimming/wading in the water.

National Park Service

This lake was first placed on Health Alert following its June 26th sample which measured at 21.24 ppb of Microcystin. The alert will remain in effect until Microcystin levels are below 20 ppb for at least two consecutive weeks.

When approaching the water at any public lake, use common sense and avoid water with a strong disagreeable odor and a layer of green scum. If you happen to come into contact with the algae, rinse off with fresh water as soon as possible. For more information on toxic blue-green algae and what to look for, see this fact sheet from the NDEQ.

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