Overview
- A bathing ban is in force at the Silbersee after laboratory tests found very high levels of the cyanobacterial toxin microcystin, and local health officials are continuing regular monitoring.
- A shallow inlet of the Bleilochstausee has been closed where the Saale flows into the reservoir and that spot will be checked weekly to see if toxin levels fall.
- Hessian authorities say most official bathing sites remain open; the state environmental office classifies the majority of EU‑reported lakes there as safe for unrestricted use while a smaller number carry warnings or restrictions.
- Cyanobacteria can produce microcystins that cause nausea, diarrhea, skin and eye irritation and breathing problems in people and can be especially dangerous for dogs that drink the water.
- Field teams sample from canoes using visibility tests, probes and depth‑stratified lab analysis, and officials advise avoiding water that is greenish or where feet are not visible at knee or hip depth because heat and shallow, nutrient‑rich conditions can worsen blooms.