Greenpeace report on the Oder: Fish deaths are probably due to mining operations


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Status: 03/02/2023 12:51 p.m

The Oder fish die-off is apparently due to salt discharges from Polish mining companies. This is shown by a current investigation by Greenpeace SWR and the “Tagesspiegel”. The focus was on tributaries where the companies discharge wastewater.

By Marilina Görz y Moratalla and Nick Schader, SWR

The pictures of the dramatic fish deaths in the Oder went around the world last summer. At that time, a significant part of the fish population and numerous other animal species had died. For a long time it was unclear what led to the environmental catastrophe.

This could change now. Scientists from Greenpeace Poland have repeatedly carried out water analyzes in southern Poland in recent weeks. Now they submitted a report to the “Tagesspiegel” and the SWR available exclusively in advance.

According to this report, several companies in the hard coal industry in the Silesia region are responsible for discharging large quantities of salt water into the tributaries of the Oder. Water experts have long agreed that unusually high salt levels in the summer had led to the proliferation of a toxic species of algae (Prymnesium parvum), which was causing the fish to die. Only where the salt came from was previously unclear.

Problematic salt water from mining

The current Greenpeace investigations focused on the tributaries of the Oder, into which mining operations discharge their waste water. There are numerous hard coal mines in the region. These constantly pump large quantities of water out of the tunnels so that work can be carried out there. It is known that this “pump water” can be very saline, depending on the region.

Greenpeace scientists took water samples from around the mining operations several times and analyzed them. Greenpeace documented the highest salt concentrations in the Oder tributaries Klodnica, Bierawka and Bielszowicki, where several hard coal mines are located.

According to the investigation report, a clear picture emerged. While above, i.e. upstream, the salinity was very low, the salinity increased massively from the discharge points of the mines. In several places, the salt concentration was even higher than in sea water. Greenpeace toxicologists are certain that these salts led to the massive proliferation of toxic algae.

Christian Wolter, fish ecologist at the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), welcomed in an interview with the SWR the Greenpeace investigation: “It was important that samples were taken at the discharge points in order to clearly identify the polluters. The results of this report thus confirm what the Leibniz Institute for Freshwater Ecology and Inland Fisheries has long pointed out: The optimal growth conditions for the toxic algae, i.e. the high salt concentration in the Oder, were caused by humans.”

“Chronically ill”

The largest Polish mining company, Polska Grupa Górnicza (PGG), which operates most of the mines in the catchment area, answered questions from the SWR not despite multiple requests. The company JSW SA, which operates a mine there, said on request: “The discharge of salt water into the environment is based on permits from the competent authorities. There have been numerous checks, during which no irregularities were found.”

The Polish Ministry of the Environment answered specific questions from the SWR neither – only said in general about their water controls: “The central research laboratory for environmental protection carries out tests and measurements including sampling for the purpose of control activities and state environmental monitoring. In this context, samples of the Oder water are currently taken twice a week at 20 measuring and testing points .”

If you look at the publicly available measurement results from the Polish authorities, you will also find that the limit values ​​for salt content are exceeded again and again. The Polish Ministry of the Environment, which comes to similar conclusions as Greenpeace, writes: “The highest salt levels are observed in the upper reaches of the river, where underground water from the coal mines is discharged.”

Dietrich Borchardt, hydrobiologist at the Helmholtz Center for Environmental Research (UFZ), has been warning for some time that the Oder is “chronically ill”: “What the Oder needs now is consistent monitoring of the discharges, coupled with further measures to strengthen the resilience of the river River ecosystems. We have already seen that rivers can recover in this way in other severe cases, such as the Rhine.”

Greenpeace warns of further environmental disasters

Greenpeace Poland warns that such an environmental disaster could happen again. In addition, not only the Oder, but also the Vistula is massively affected by the massive salt water discharges from the mining industry. In its final report, Greenpeace therefore calls on the Polish environmental authorities to take action. Immediate environmental assessments would have to be carried out at the mining operations, the amounts of waste water would have to be reduced and desalination plants installed.

It is still unclear whether and how the Polish environmental authorities will act, as the results of the investigation by Greenpeace Poland were only published today. But the pressure is likely to increase.

Fisheries expert Christian Wolter from the Leibniz Institute: “We hope that behind the scenes at the political level work is already being done on solutions such as retention basins or the determination of an ecologically compatible limit value on a scientific basis.” The discharges must be reduced urgently so that the environmental disaster does not repeat itself this summer.

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