"Half of cyanobacteria are toxic and can be hazardous to people's health, so we currently recommend avoiding swimming at Pirita Beach," said Pirita Deputy City District Elder Aleksandra Pavlova. "Should one decide to go in the water anyway, they must ensure that they do not ingest any water and that they thoroughly wash themselves after swimming."

The symptoms of cyanobacteria poisoning are similar to flu symptoms and include fever, cold, muscle pain, malaise, diarrhea and redness of the skin and eyes. Should one accidentally swallow water containing cyanobacteria, they should induce vomiting as soon as possible. Charcoal tablets may also be taken.

 "Lifeguards are on duty at Pirita Beach who may also be consulted," Pavlova noted. "Both the Tallinn Environment Department as well as the Ministry of the Environment are informed about the cyanobacteria."