In the search for the cause of the fish kill in the Oder, the cause remains unclear. However, the results of the water samples already show a dramatic change in values ​​since August 7th. The oxygen content, the pH value, the turbidity and other values ​​suddenly went up, while the amount of nitrate-nitrogen fell significantly, show data from the Brandenburg State Environment Agency, which the authority publishes online.

However, the search for the cause does not bring this data any further. The authority is currently evaluating new laboratory results. The results transmitted on Monday evening by the Berlin-Brandenburg state laboratory in a first tranche did not show particularly high values ​​for metals such as mercury, said the spokesman for the Ministry of the Environment, Sebastian Arnold, on Tuesday on request. A single cause for the environmental catastrophe cannot be identified.

“The studies on nutrients that are not yet complete and not yet comprehensive and completed do not yet allow any indication of a single cause for the fish kill in the Oder,” explained Arnold. “Furthermore, high salt loads and a high oxygen content are found.” The state laboratory is examining other water samples from different days and measuring points as well as fish. The data would be continuously transmitted and evaluated.

Arnold explained that water samples on the Brandenburg side would be taken regularly at the automatic measuring station in Frankfurt (Oder). Samples are taken at regular intervals 1.5 meters below the surface of the water and are usually analyzed for values ​​such as water temperature, pH or oxygen content. Arnold explains that the samples in the state laboratory are now being examined for numerous other values ​​and toxins.

According to their own statements, the Polish fire brigade has so far recovered almost a hundred tons of dead fish from the Oder and the smaller river Ner. A total of 97.95 tons, said the spokeswoman for the fire brigade headquarters in Warsaw on Tuesday. The majority of this is accounted for by the dead fish from the Oder.

The Ner is a small river that rises south of Lodz and flows into the Warta. About 25 kilometers north of Frankfurt (Oder) this finally flows into the German-Polish border river. Dead fish have also been discovered in the Ner for a few days. The cause of the fish deaths there is unknown – as is the case for the natural disaster in the Oder.

In Brandenburg, too, helpers collected the fish carcasses on the Oder. The dead animals are destroyed in special incinerators. There was no information about the quantities collected in Germany.

According to Polish authorities, dead fish have also been found south of the port city of Szczecin in canals connected to the Oder. This means that the contaminated water masses are moving towards Szczecin, said the head of the regional administration for the West Pomeranian Voivodeship, Zbigniew Bogucki, on Tuesday.