Poland warns of toxic cyanobacteria blooms in Baltic Sea and lakes

Health authorities in Poland have issued alerts about cyanobacterial (blue‑green algae) blooms in the Baltic Sea, the Gulf of Gdańsk and numerous inland lakes. The bacteria can produce hepatotoxins, neurotoxins and dermatotoxins that may cause liver and kidney damage, respiratory distress, skin irritation, nausea, vomiting, headaches and fever.

Blooms are favoured by warm temperatures above 20 °C, nutrient enrichment from agricultural runoff and sewage, and stagnant water. Visible signs include green, blue‑green or reddish surface scums, foul odours and foamy water. Inhalation of airborne toxins around affected water bodies also poses a risk, especially to children.

Officials advise the public to avoid swimming, wading or spending time near water showing dense scums, and to follow local water‑quality updates. Early recognition of symptoms and prompt medical treatment are recommended.