Summer means nice, warm temperatures and a lot of people out enjoying themselves on lakes throughout Minnesota.
Before going outside, there are basic things people know to do to stay safe, such as wearing sunscreen to prevent skin cancer, following basic water safety guidelines to avoid accidents on the water, and more.
However, there is also an environmental risk that people may not think to look for, but it's crucial to be aware of, especially if you have children and pets, because it can cause serious illnesses and even death.
Watch Out For Potentially Deadly Bacteria Now In Minnesota Lakes
Blue-green algae, technically known as cyanobacteria, are microscopic organisms that exist naturally in freshwater, brackish water, and marine environments.
According to the DNR, blue-green algae, which are actually a type of bacteria, can be found at any time in Minnesota waterbodies, but they are primarily found from mid-June through late September, with peak bloom season in July and August when waters are the warmest.
When environmental conditions are just right, blue-green algae can proliferate to form visible accumulations called “blooms.” Planktonic blue-green algae blooms float to the surface and form scums, paint-like conditions, or “pea soup” water containing billions of tiny particles.
Blue-green algae can produce several different toxins. Exposure to these toxins is possible through contact with the skin while swimming, through inhalation when doing recreational activities such as boating, jet skiing, or water skiing, or by swallowing contaminated water.
Types of toxins and potential health effects include the following:
Dermatotoxins and Gastrointestinal Toxins: These toxins affect the skin and mucous membranes, and can cause allergy-type reactions such as rashes, eye/nose/throat irritation, and asthma, as well as headaches, fever, and gastroenteritis (nausea, stomach cramps, vomiting, diarrhea).
Hepatotoxins: These toxins affect the liver and other internal organs, and can cause gastroenteritis, tissue damage, muscle weakness, paralysis, and respiratory failure (with acute exposure), tumors, and possibly liver cancer (with long-term, chronic exposure).
Cytotoxins: These toxins also affect the liver and other organs (though through a different mode of action than hepatotoxins) and can cause malaise, headache, anorexia, vomiting, chromosome loss, DNA strand breakage, and damage to organs.
Neurotoxins: These toxins affect the central nervous system and can cause seizures, paralysis, respiratory failure, or cardiac arrest.
How To Spot Blue-Green Algae
Blue-green algae can appear in two distinct ways:
Planktonic blue-green algae look like tiny particles, dust, or grass clippings floating in the water and are most often green, tan, reddish-purple, or blue.
Bottom-dwelling mats of benthic blue-green algae can float to the surface, often brown, black, or turquoise.
Symptoms of blue-green algal toxin poisoning in people include vomiting and diarrhea from ingestion, sore throat, and wheezing from inhalation. Some people also experience skin irritation and rashes in areas where the algae are held against their skin under clothing.
It's important to note that even lakes with excellent water quality may occasionally experience small blooms, especially after calm weather. Bottom-dwelling benthic mats are often reported in lakes with clear water since sunlight needs to reach the bottom.
How To Stay Safe On And Offshore And Symptoms Of Toxin Poisoning
It's crucial to know what it looks like and to always assess conditions before swimming.
Experts say you can stay safe by following these best practices:
Do not swim in water that looks like "pea soup," spilled paint, or water that has a scum layer, mats, or puffy blobs floating on the surface. All of these may be blue-green algae, and the abundant particles can also host high levels.
Do not boat, water ski, etc., over such water to reduce inhalation exposure.
Do not let children play with scum layers, even from the shore.
Always shower after contact with any surface water, whether or not a blue-green algae bloom appears to be present, since surface waters may contain other species of potentially harmful bacteria, viruses, or parasites.
Always avoid swallowing untreated surface water because it may contain bacteria, viruses, and parasites that could make you sick.
When in doubt, stay out.
How To Protect Your Pets
If you have pets that love water, it's important to remember that blue-green algae can have harmful effects if ingested. Dogs are not deterred by surface scum and can swallow water while swimming. They may eat floating material in the water or mats washed up on shore, or lick blue-green algae from their coats after swimming.
If the blue-green algae they ingest produce toxins, the animals can become ill and even die.
When looking for a safe place for pets to swim, choose the clearest water possible and keep pets out of areas with accumulations of blue-green algae or dense particulate matter. If there's any doubt about what is in the water, keep your pets out.
Other tips to keep pets safe include:
Do not let pets or livestock swim in or drink water experiencing blue-green algae blooms.
Always offer fresh, clean water for pets to drink instead of lake water.
Give dogs plenty of breaks from swimming and retrieving in lakes.
Avoid having dogs bite at splashed water as a game, and use flat objects for retrieval instead of balls.
Wash pets off with clean water immediately after swimming so they don't lick any algae from their fur.
Supervise pets when outside so they don't eat algal scum accumulated on the shore or floating mats of algae or drink lake water.
If a pet eats grass, avoid using lake water for lawn irrigation if blooms are present.
Symptoms of blue-green algal toxin poisoning in pets may range from lethargy and weakness to vomiting, diarrhea, difficulty breathing, loss of coordination, and seizures, requiring immediate veterinary care.
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