In the summer of 2022, large numbers of fish died in the Oder. Has enough been done to prevent this from happening again? Experts are skeptical – especially considering the Polish side of the river.
August a year ago: It is hot and dry, resulting in exceptionally low river levels. A catastrophe occurs in the Oder on the German-Polish border: from August 9, thousands of dead fish are floating on the surface of the water.
For days, the authorities groped in the dark. Reporting chains between Poland and Germany fail. Federal Environment Minister Steffi Lemke is upset. “I believe that all decision-makers are now responsible for identifying this polluter,” said Lembke at the time. Even more: “The fact that the information really reached us very late, too late, now makes it more difficult to identify the cause of the damage.”
Mass extinction due to high salinity
It takes around seven weeks for the cause of the damage to be officially clarified. Too much salt in the river, combined with heat and low water levels, leads to the proliferation of an alga with poisonous flowers, which has caused mass fish kills.
Experts have now found out where the salt comes from. Christian Wolter from the Leibniz Institute for Freshwater Ecology and Inland Fisheries explains that the salt reportedly comes from the coal mines in the Silesian Odra river basin. “There it occurs as sump water, so it’s practical for pumping the tunnels empty and being able to mine the coal,” he says. The water has a high salt content.
Germany and Poland promise protective measures
Big announcements follow – on the Polish and German side. The salt water from the mining industry should no longer get into the Oder to the same extent as before, and the river must be better protected. An expert group is set up.
But how is the situation one year after the environmental catastrophe? Various measures have been tested, but according to the scientist, they are not ideal. “It’s tinkering with the symptoms.” Trying to do something about the algae bloom.
However, the real problem has not been solved – namely stopping or at least significantly reducing the discharge of salt water into the river.
Still high salt load
According to researchers, the salinity in the Oder is still high. If the heat and drought return, a catastrophe could quickly follow, says Wolter.
The situation is still critical because we actually have a high level of salt pollution. And this algae is in the water now. It is no longer a question of whether it might come at some point, it is there. So that we now have a significantly greater risk than a year ago that such blooms can also occur.
They are poisonous flowers that killed up to 1,000 tons of fish last August. Large mussels, which actually serve the purpose of purifying the water, also died.
Experts are assuming a man-made catastrophe in the Oder: first the salinity increased extremely, then the algal bloom came.
Federal Environment Minister warns of a new catastrophe
Federal Environment Minister Lemke is also warning of a new environmental catastrophe. The Greens politician has appealed to the Polish side several times – as recently in a video message. Accordingly, it is “the most important and urgent requirement that the salt discharges be reduced, at least now in summer, so that this wonderful ecosystem is not disturbed again or even destroyed”. So far, her words have not led to success.
The minister wants to establish a German-Polish early warning system in order to be able to act quickly and in a coordinated manner, if necessary. But the Polish authorities have not yet responded to this request either. They point out that river water should be strictly monitored.
Environmentalists and scientists hope to get off lightly this year – assuming there is no more major heat wave.