LANSING, Mich. — Michigan Department of Health and Human Services officials are urging residents living near or visiting waters in the summer or fall months to be aware of the potential for harmful algal blooms.
Harmful algal blooms (HABs) form due to a rapid overgrowth or bloom of cyanobacteria, also known as blue-green algae, according to a news release Tuesday.
Some Cyanobacteria produce toxins, called cyanotoxins, that can be present in their blooms, which at higher levels can be harmful to people and animals.
HABs usually occur in Michigan in May through October, most commonly in August and September.
During 2020, 61 HABs in 35 Michigan counties were reported to the Michigan Department of Environment, Great Lakes and Energy.
“Before going in the water, we recommend Michiganders look for visible algal blooms or scums on any lake, and that people and pets stay out of water in areas that look affected,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health for MDHHS. “If you may have had contact with or swallowed water with a HAB and feel sick, call your doctor or Poison Control at 800-222-1222. If symptoms are severe, seek emergency medical attention as soon as possible.”
State officials say HABs can look like algal scums or mats, spilled paint or pea soup or colored streaks on the water’s surface.
Blooms may last for days or sometimes weeks, and can change in size, toxicity and location within the same day. They may also disappear on a waterbody but then form at a later time.
Unless the bloom covers a large part of the lake, people can still use any part of the lake that is not affected.
People and pets should always be rinsed off after contact with any lake water.
Breathing in or swallowing water containing HABs and their toxins can cause runny eyes or nose, asthma-like symptoms, stomach pain, vomiting, diarrhea, weakness, numbness, headaches, dizziness or difficulty breathing.
Skin contact can cause rashes, blisters and hives.
Animals – especially dogs – can become sick or die after contact with HABs. Signs of illness can include vomiting, diarrhea, staggered walking and convulsions.
Michiganders help prevent HABs from occurring by learning about nutrient pollution, such as excess nitrogen and phosphorous that may come from detergents, sewers, fertilizers and malfunctioned septic systems.
Residents can decrease nutrients getting into water by:
- Using phosphate-free detergents
- Disposing of pet waste properly
- Applying fertilizer only when necessary and applying the recommended amount according to label instructions. A buffer should be left when applying fertilizer near a lake or stream.
- Promoting the use of natural shoreline – as opposed to hardened shoreline – including growing native vegetation along the water’s edge.
- Joining a local organization or like-minded residents to develop or update a watershed management plan if one does not already exist or is out-of-date. This identifies pollutants that are causing water quality problems, the sources of those pollutants and recommends actions that can be taken to reduce pollutant inputs into surface waters.