How did the pollution get into the Seym and Desna rivers? What threats do the waste materials that entered the rivers pose to their ecosystems? When will all the consequences of the environmental disaster end? Have there been similar disasters in the past and how did they conclude? The director of the Institute of Hydrobiology of the NAS of Ukraine, academician of the NAS of Ukraine Serhiy Afanasyev answered these and other questions in an interview with the online publication "Vechirniy Kyiv".
"The pollution is related to the entry of waste into the Seym from the settling ponds of sugar and alcohol factories in the Russian city of Tyotkino, Kursk region. We are talking about a thick liquid that remains after processing sugar beets and sugarcane. The settling ponds of the Tyotkino factories are located on the bank of the Seym. Whether they were damaged as a result of hostilities or this was a planned action by the Russians is unknown. But this 'molasses' and industrial wastewater entered the Seym River. A large amount of organic matter absorbed oxygen in the water, which caused mass death of fish and invertebrates in the Sumy and Chernihiv regions. The decomposition of the dead organisms added its share of secondary pollution to the rivers," the scientist said.
Regarding this waste, Serhiy Afanasyev noted that it is not highly toxic, as biotesting did not reveal any toxins. However, a genotoxicity test, which is somewhat more complex, is still ongoing, and the results will be known by the end of this week.
The scientist also addressed the issue that this waste could reach Kyiv, assuring that it could reach our city, but in his opinion, Kyivvodokanal has all the necessary means and reagents to purify the water. Moreover, the pollution has already been diluted by the Desna at least threefold. In addition, the speed of the pollution patch has decreased because it is denser and flows more slowly along the bottom. Cleaner water flows on top, which picks up pollution from below, washes it out, and dilutes it.
Regarding the consequences of the pollution, the scientist stated: "The pollution patch, absorbing oxygen, destroyed everything in its path. Now the Seym has turned into a dead river. Due to lack of oxygen in the water, not only fish suffocated. Invertebrates also died: mollusks, arthropods, insects, worms. On one hand, they are a food base for fish; on the other, they have special significance as filter feeders for water purification and play a major role in the entire river ecosystem. However, rivers differ in their dynamics and impress with their ability to self-recover."
The ecosystems of the Seym and Desna are capable of recovery within 2-3 years. However, the loss of biodiversity, endangered species of fish and invertebrates, cannot be assessed today.
Additionally, the scientist recalled a similar incident that occurred in 1983 in the Lviv region, when in the city of Stebnyk, Lviv region, after heavy rain, a soil dam of a tailings pond broke. A huge mass of highly concentrated brine from the potash plant poured into the basin of the Solonytsia River and further into the rivers Dniester and the Black Sea.
Regarding this disaster, the scientist noted: "It caused enormous damage to the flora and fauna, as well as to the quality of water in local water intakes. The brine wiped out all living things in its path. A section of the Dniester over 500 kilometers long became dead. Hundreds of thousands of tons of fish died then. However, within five years, the Dniester recovered. Today, we cannot even find traces of that disaster."