Following the proliferation of cyanobacteria, commonly referred to as "blue-green algae", in the Lac Haute-Sûre, which has been accompanied by the presence of high concentrations of toxins produced by these cyanobacteria, the water Management Administration has announced that the situation has improved significantly.

The seasonal changes in climatology and hydrodynamics of the Lac Haute-Sûre have led to a sharp decline in cyanobacterial biomass and the dissipation of blooms. The analyses conducted by the Luxembourg Institute of Science and Technology (LIST) have shown that cyanotoxin concentrations that can cause health problems in humans and animals have also dropped considerably. This evolution of the situation puts an end to the alert to microbiological and toxic risks in public health related to the presence of cyanobacteria blooms.

Practice recreational and sports activities

The practice of recreational and sports activities, with the exception of swimming, can resume. In this context, the Water Management Administration has stated that, in accordance with the provisions of the Grand-Ducal Regulation of 8 July 2017, the bathing season ended on 30 September 2017 (it runs from 1 May to 30 September); outside these dates, swimming in official bathing sites is prohibited.

Consumption of fish emptied is no longer discouraged

With regard to the consumption of fish caught in the Lac Haute-Sûre, the Food Security Division of the Directorate of Health recommends the public not to consume fish caught during periods of cyanobacteria bloom. However, it can not exclude the bioaccumulation effect of toxins produced by cyanobacteria in the livers of fish. In conclusion, the consumption of eviscerated fish is no longer discouraged.