Blue-green algae alarm at the Naab: Citizens in Kallmünz warned!

Blue-green algae alarm at the Naab: Citizens in Kallmünz warned!

On August 22, 2025, dangerous blue-green algae, more precisely the cyanobacteria of the species Microcystis, were discovered during a sampling in the Naab near Kallmünz. This was announced by the municipality of Kallmünz, which also provided information about the status of the water. Although the river looks visually unremarkable in the free-flowing area, accumulations can form in quieter bank zones and storage areas. Visible symptoms of blue-green algae include streaking and greenish-blue deposits on the water surface and represent a significant health risk.

The health risks from contact with blue-green algae should not be underestimated. Symptoms such as skin and mucous membrane irritation, nausea, vomiting and diarrhea as well as headaches can occur in people who come into contact with contaminated water. Nationwide reports, such as from NDR, emphasize that blue-green algae proliferation is particularly encouraged during the warm season and under suitable weather conditions such as little wind and strong sunlight.

Behavioral recommendations for citizens

The municipality is urgently issuing behavioral recommendations to protect the population. Bathing areas with visible accumulations of blue-green algae should be avoided. Contact with skin and swallowing water should also be avoided. Dogs and other pets should be kept away from contaminated water as their health can also be at risk. Consumption of fish from affected areas is also discouraged.

There is also the possibility that exposure to blue-green algae varies rapidly depending on weather conditions. It is recommended to regularly inform yourself about the water quality and possible bathing bans. According to the Pharmacy look around Toxic substances produced by some blue-green algae can be particularly challenging. These toxic substances pose various health risks, especially for pregnant women, immunocompromised people and children.

Preventive measures

In order to minimize the spread of blue-green algae in water bodies, preventive measures against over-fertilization and high nutrient inputs into water bodies are necessary. High nutrient pollution, particularly phosphorus and nitrogen, plays a crucial role in the increase in the amount of blue-green algae. The increasing occurrence of these organisms is also being exacerbated by climate change, as rising water temperatures and longer warm periods promote their proliferation.

The health risk posed by contact with blue-green algae therefore requires both personal precautionary measures and social responsibility to ensure healthy and safe water quality in pools and bodies of water. Further information will be provided by the municipal administration in the future as soon as current operational situations are known.