There's a danger lurking in many of our lakes. Residents need to know it's there - and how to stop it.

It's blue-green algae, which poses a health hazard to people and animals.

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Last summer, blue-green algal blooms were reported in lakes across the state. Pollution experts and the Minnesota Department of Health jointly investigated two reported human illnesses and multiple dog deaths following exposure to blue-green algae.

Dogs in Douglas County have gotten sick from ingesting algae in past summers. Once exposed to blue-green algae, they can experience symptoms such as vomiting, diarrhea, rash, difficulty breathing, general weakness, liver failure, and seizures. If your dog experiences any of these symptoms after visiting a lake, seek veterinary care immediately. In the worst cases, blue-green algae exposure can cause death.

Not all blue-green algae are toxic, but there is no way to tell whether a bloom is toxic by looking at it. Harmful blooms often look like pea soup, green paint, or floating mats of scum and sometimes have a bad smell. However, harmful blooms aren't always large and dense and can sometimes cover small portions of the lake with little visible algae present. Before you or your children or pets enter the water, take a closer look at the lake and check for algae in the water or on shore to help determine if a bloom recently happened.

"If it looks and smells bad, don't take a chance. We usually tell people: If in doubt, stay out," says Pam Anderson, pollution control water quality monitoring supervisor. "If you're not sure, it's best for people and pets to stay out of the water."

Residents can take steps to prevent algae problems. One key is to improve overall water quality by reducing how much phosphorus gets into lakes. Phosphorus is a nutrient that encourages plant growth, and is present in soil and plants. Runoff from urban and agricultural land contains phosphorus. Excess phosphorus in lakes provides the food necessary to produce algal blooms.

The Minnesota Pollution Control Agency lists three simple things residents should do: 1. Limit applications of fertilizers that contain phosphorus. 2. Clean up pet waste, so that rain storms don't wash the material into nearby lakes and rivers. 3. Protect lakes by sweeping up lawn clippings and soil off sidewalks and pavement.

Why should grass clipping be kept out of the street?

One bushel of grass clippings contains enough phosphorus to produce 30 to 50 pounds of algae, according to Alexandria city leaders who issued a reminder about the problem this week. The clippings can travel with the stormwater runoff through the storm system until it reaches a waterbody.

In addition to posing a health hazard, algae scum are an eyesore on our otherwise beautiful lakes. Also, too much algae harms a lake's system because it blocks sunlight and prevents other plants from growing.When the algae dies and decays, it takes much needed oxygen away from fish and other aquatic species.

There are also legal consequences for not property disposing grass clippings. Alexandria's Ordinance 722 states that grass intentionally disposed of in a street, road, alley, catch basin, culvert, curb, gutter, inlet, and other unnatural locations, is considered an illegal disposal and fines to the disposer may be enforced.

Here's a tip: The next time you mow your lawn, make the first few passes blowing the grass clippings into the lawn, not the street. If there are grass clippings that land on the street or paved surface, use a broom or leaf blower to blow them back into the lawn. Don't use a hose to wash them into the street or storm drain.

Residents should go the extra mile in keeping leaves and lawn clippings out of streets and gutters. Our lakes deserve it.

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Echo Press editorials represent the opinion of the Echo Press Editorial Board, which includes Jeff Beach, Editor; Jody Hanson, Publisher; and Al Edenloff, News/Opinion Editor.