Oder river water contaminated causing the mass extinction of fish

Tonnes of dead fish have been hauled out of the River Oder, which flows along part of Poland's border with Germany, and officials warned people not to enter the water while the Polish government pledged to investigate possible contamination.

Volunteers and anglers have removed at least 10 tonnes of dead fish from the 200-kilometer stretch of the river north of Olawa in southwest Poland, Przemyslaw Daca, head of State Water Holding , said on Thursday. Daca, whose agency manages Polish national waters, called the situation a gigantic ecological catastrophe.

Environmental authorities said they notified prosecutors about potential contamination of the country's second longest river. Prime Minister Mateusz Morawiecki vowed to punish those responsible.

Dead fish can be found 300 kilometers north of Olawa, Ewa Drewniak, a biologist working with opposition group Civic Coalition, told Reuters on Thursday, accusing the government of not responding quickly enough. "Dead fish have been flowing in the Oder for the past two weeks and people have not been informed about it, I've seen scores of people bathing in the river a week and a half ago, they were not aware of the danger, this is scandalous," she said.

Regional environmental protection authorities in Wroclaw said Oder water samples taken on July 28 showed an 80% probability that they contained mesitylene, a toxic substance, although this was not present in samples taken after Aug. 1.

Low river levels due to the drought in Europe might have aggravated possible contamination, Daca said on Wednesday. He added they suspected a strong oxidizing agent might have gotten into the water causing oxygen levels to spike, which can harm fish. He added there was no reason for panic and the situation was improving.

Several German districts bordering Poland warned locals to avoid the river water and not to eat fish from the Oder as long as the cause of the fish deaths was unclear.

"The reports from the Oder are simply terrible," Michael Kellner, a senior politician of Germany's Greens, said on Twitter.