The discharge of wastewater from the settling ponds of a sugar factory in Tyotkino, Kursk Region, Russia, into the Seym River caused the organic pollution of this river and, subsequently, the Desna River, said Ihor Hopchak, Deputy Chairman of the State Water Resources Agency of Ukraine, citing findings from the Ukrainian Hydrometeorological Institute.

"The Ukrainian Hydrometeorological Institute concluded that satellite images showed the settling ponds of the sugar factory in Tyotkino were full of water in July, but by early August, they were empty. This indicates that these pollutants entered the Seym River from Russia and flowed downstream into Ukraine," Hopchak stated during a national TV marathon on Sunday.

Citing preliminary data from the State Environmental Inspectorate, he said that damages amounted to approximately UAH 415 million, although this figure may be revised.

In August, the Regional Water Resources Office in Sumy Region reported a deterioration in the water quality of the Seym River, including mass fish deaths. No chemical or highly toxic components were detected, and the pollution was determined to be organic.

There was no threat to the drinking water supply in Chernihiv and Sumy regions. Swimming and fishing in both rivers were prohibited. By September 5, organic pollutants had reached Chernihiv via the Desna, moving in patches along the river's deepest sections and gradually settling on the riverbed. By September 15, the pollutants had reached Kyiv Region. According to Kyivvodokanal and scientists' assessments, Kyiv's water treatment facilities should be able to handle the contamination if it reaches the city's water intake points.

In Sumy region, over 12 tonnes of dead fish were collected and buried from the Seym River, while in Chernihiv region, 19 tonnes of dead fish were collected from the Seym and Desna Rivers.