Bodrog River faces ecological threat from massive duckweed infestation

A massive infestation of duckweed has covered large sections of the Bodrog River, particularly in the areas between Tokaj and Sárospatak. The dense green layer creates a continuous blanket on the water surface, which experts warn could block oxygen exchange and lead to mass fish die-offs.

Authorities have responded to the crisis, with the North Hungarian Water Management Directorate declaring a level III water quality emergency. So far, approximately 300 tons of duckweed have been removed from three different locations using specialized machinery and diving walls to herd the vegetation.

The phenomenon is considered unusual for a flowing river, as duckweed typically thrives in stagnant waters. Experts suggest the infestation may have originated from Slovakia and was exacerbated by recent extreme heat and drought, which slowed water movement and turned parts of the river into near-stagnant conditions.