Warning over bacteria: Blue-green algae in Edersee; district warns against swimming in Rehbach

The district of Waldeck-Frankenberg in Germany has issued a warning against swimming at the Rehbach bathing area of Edersee due to a substantial proliferation of blue-green algae. Regular water quality checks revealed elevated levels of cyanobacteria, prompting the advisory. The warm weather, intense sunshine, and critically low water level in the Edersee reservoir, which is currently only about 18.5% full, are contributing factors to the algae's development.

While other official bathing areas at Edersee Waldeck West have not shown concerning developments so far, officials caution that this situation can change rapidly. "Blue-green algae can develop very quickly – and disappear just as quickly," explained hygiene inspector Hendrik Graf. The speed of development and disappearance depends heavily on weather conditions, water depth, sunshine, and nutrient concentration in the water. Similar warnings or restrictions due to cyanobacteria are currently in place at several other Hessian bathing waters, including the Schultheis-Weiher, Große Woog, Arheilger Mühlchen, Licher Waldschwimmbad, and the Grüne See.

Health authorities emphasize that contact with blue-green algae can cause various health problems, including skin irritation, nausea, vomiting, stomach and intestinal complaints, and respiratory issues. Children and pets are considered particularly at risk due to their sensitivity. The municipality of Edertal plans to install warning signs at the Rehbach bathing area to inform the public. Checks at the monitored bathing areas on Twiste- and Diemelsee have not detected any blue-green algae to date.

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Blue-green algae can develop very quickly – and disappear just as quickly.