No toxic substances proven to cause fish death in Odra says minister

No toxic substances have been found in water samples taken from the River Odra, where masses of dead fish have been found, Poland's climate and environment minister has said.

More than ten tonnes of dead fish have been found since late July in the Odra, Poland's second largest river, which also runs through Germany.

The exact cause of the mass fish die-off, which was labelled an "ecological disaster," remains unclear.

Anna Moskwa, speaking after meeting her German counterpart in Szczecin on Sunday, said that "as of today, none of the (water) tests have confirmed the presence of toxic substances."

"At the same time, we are conducting tests on fish. We have completed tests for mercury and heavy metals. Neither mercury nor heavy metals were found in the collected samples," she added.

Moskwa also said that checks for around 300 more substances would be carried out.

"We have made a decision to send some of the samples to other foreign laboratories. In the coming hours, the samples will be tested for 300 possible substances, now they are being tested for the presence of pesticides," she said.

Moskwa added that, at the same time, tests on the dead fish are being conducted.

"We have made a decision to carry out comprehensive autopsies on the fish, but also on the analysis of fish behaviour in the last moments before dying," she said.

"We are analysing various possibilities, including the introduction of hazardous substances that may have killed the fish, although we have not identified any, while also taking into account the possibility of a natural environmental cause," she said.

According to Moskwa, however, toxic substances cannot be ruled out as the cause of fish death so therefore entities which run businesses and industrial activities along the river are being checked.

Steffi Lemke, the German environment minister, said on Sunday that "we are dealing with a major environmental disaster."

"We do not know how long and to what extent this catastrophe will affect the ecological system and whether it will last for months or maybe years," she said.

Lemke also announced that a meeting of the International Commission for the Protection of the Odra River against Pollution (ICPO) had been scheduled for August 18.

Meanwhile, on Monday afternoon, Karol Kierzkowski, the spokesman for Poland's Fire Service, told PAP that since Friday, firefighters had hauled out as many as 80 tonnes of dead fish from the River Odra. (PAP)