Cyanobacteria: Blue-Green Algae Dim Hopes for Swimming Fun – Warnings Issued for Several Lakes

Swimmers in Hesse are facing disruptions to their summer plans as several lakes report significant blooms of cyanobacteria, commonly known as blue-green algae. These microorganisms are increasingly clouding the water, raising health concerns for recreational users.

At Schultheis-Weiher in the Offenbach district, a swimming ban was imposed at the end of June. Additionally, the Hessian State Office for Nature Conservation, Environment, and Geology (HLNUG) advises against swimming in three other bodies of water for health and safety reasons. These include the Grüne See in Witzenhausen, where the water is heavily turbid with visibility limited to 70 centimeters, as well as the Guckaisee in the Rhön region and the Große Woog in Darmstadt.

Further warnings extend to other lakes, including Badesee Mainflingen near Seligenstadt and the Marbach Reservoir in southern Hesse. Authorities caution against areas with green streaks on the water's surface and severe turbidity. The HLNUG recommends a simple rule: if you cannot see your feet when standing knee-deep in the water, refrain from swimming. Greenish-blue streaks and unpleasant odors are also considered warning signs.

Contact with water contaminated by blue-green algae can lead to various health problems. These include gastrointestinal distress, as well as skin and eye irritation. Information on specific water bodies is available on the HLNUG website.