Blue-green algae blooms pose health risks

Exceptionally abundant blooms of blue-green algae, i.e. cyanobacteria, in water have increased the risk of adverse health effects, said Finnish Environment Institute (SYKE) in a press release.

Water containing blue-green algae must always be considered a potential health risk. If there are blue-green algae in water, it must not be consumed by people or animals, not even after boiling.

Algal toxins will still be present in water for a few days after a visible bloom has disappeared.

Children and pets must not be allowed to swim in water contaminated by blue-green algae, and grown-ups should also avoid swimming.

If anyone suspects having been exposed to contaminated water, he or she should wash with clean water after swimming.

Pets should also be washed with clean water, as they could become exposed to algal toxins by licking their fur after swimming.

Water contaminated with blue-green algae must never be thrown onto the sauna stove. Exposure to contaminated water through one’s skin and respiration causes even more symptoms than swallowing. Exposure through the skin and respiration may also occur in water skiing and other watersports where mist is abundant.

Water contaminated with blue-green algae should not be used for washing dishes or for watering edible plants.

Crayfish and fish caught from waters contaminated with blue-green algae are edible except the liver.

The most common symptoms of exposure to blue-green algae are associated with the stomach: nausea, pain, diarrhoea and vomiting. Symptoms can also appear on one’s skin, such as rash and sting of the lips, or one may have symptoms similar to flu, such as sniffles, headache, irritation of the eyes and high temperature. The symptoms usually start within a few hours of exposure and last for a few days, not more than a week.

Skin exposed to blue-green algae should be washed with clean water and soap. Eyes are to be rinsed with plain water only. If anyone has stomach-related symptoms, it is important to maintain good hydration. Painkillers or fever medication are usually not required.