What killed tons of fish in a European river? The mystery deepens

By Judy J. Beasley Last updated Jan 7, 2023

WARSAW, Poland (AP) — Another lab study mass extinction of fish high levels of salinity have been detected in the Oder, but no mercury poisoning has been found in its waters, the Polish environment minister said on Saturday, while the mystery continues to explain what killed tons of fish in central Europe.

Anna Moskva, Minister of Climate and Environment, said analyzes of river samples taken in both Poland and Germany showed elevated salt levels. She added that comprehensive toxicological studies are still underway in Poland.

She said Poland’s state veterinary office examined seven species of dead fish and ruled out mercury as the cause of the extinction, but was still awaiting results from other substances. She said test results from Germany also showed no high levels of mercury.

The Oder flows from the Czech Republic to the border between Poland and Germany before flowing into the Baltic Sea. Some German media suggested that the river was poisoned with mercury.

Prime Minister Mateusz Morawiecki said on Friday that “huge amounts of chemical waste” were likely deliberately dumped into his country’s second-longest river, causing environmental damage so severe that it would take years to rebuild the waterways.

On Saturday, Morawiecki announced that he would do everything to limit the devastation of the environment. Poland’s interior minister said a reward of 1 million zlotys ($220,000) would be paid to anyone who helps track down those responsible for polluting the river.

Authorities in the north-eastern German state of Mecklenburg-Vorpommern have warned people not to fish or use water from the Szczecin Lagoon as polluted water from the river is expected to reach the estuary area on Saturday evening.

“The scale of fish extinction is shocking. This is a blow to the Oder as a waterway of high ecological value, from which it is unlikely to recover for a long time,” said Alex Vogel, Minister of the Environment of Brandenburg, through which the river flows.

The head of Polish waters, the National Water Management Authority, announced on Thursday that 10 tons of dead fish had been removed from the river. Hundreds of volunteers worked collecting dead fish along the German side.

German labs said they had detected “unusual” levels of “salt” that could be linked to the extinction, but would not fully explain them on their own.

Morawiecki admitted that some Polish officials were reacting “slowly” after seeing the huge number of dead fish wash up on shore and said two of them had been released.

“For me, however, the most important thing is to deal with this ecological disaster as soon as possible, because nature is our common heritage,” Morawiecki said.

His remarks were echoed by the mayor of Schwedt, Annekathrin Hoppe, whose German town is located next to the Lower Oder Valley National Park. She called the pollution of the river “an ecological disaster on an unprecedented scale” for the region.