End of August 2022: hundreds of thousands of fish corpses pile up on the banks of the River Oder – 840 km of fresh water linking the Czech Republic, Poland and Saxony with the Baltic Sea, one of the most important Central European ecosystems. Already by the end of July, Polish fishermen had warned the local authorities that more and more fish were floating dead in the waters of the river, and before the bureaucracy had run its course, the scale of the disaster became apocalyptic and the problem had spread to the estuary on the Baltic, now threatening the North Sea[1].

Germany reacted immediately, banning fishing and bathing in the waters of the Oder, and alerted the scientific community to clarify the reasons and scale of the disaster. From Poland comes only an official communiqué, according to which Polish scientists claim that laboratory tests have detected the presence of high levels of salt (which severely decreases the concentration of oxygen in the fresh water, vital for fish[2]), but no toxic substances – nonetheless, the Warsaw and Berlin governments agree to fear poisoning by illegally discharged chemicals from some industry, not least because the German scientists, unlike their colleagues, have detected a dangerous percentage of mercury dissolved in the water: Poland is offering a reward of 1 million Złoty (about 210,000 Euro) to anyone who can ‘help find those responsible for this environmental disaster’[3].

All indications are that the search for the causes will be long and controversial, as Germany and Poland are already bouncing responsibility. According to the Polish Minister of the Environment, Anna Moskwa, ‘The state veterinary institute has completed tests on the fish for the presence of heavy metals’ and ‘has ruled out heavy metals as the cause of the fish’s death’[4]. The government sacked the CEO of Polish Waters, the state water management company, and with him the head of the Environmental Protection Inspectorate: two decisions that cast more than a few shadows on the true results of the laboratory tests[5]. Prime Minister MateuszMorawiecki claims that ‘huge quantities of chemical waste’ have been dumped into the river, causing such serious environmental damage that ‘it will take years for the watercourse to recover’[6].

The Polish government is divided: on the one side is Anna Moskwa’s thesis that the disaster occurred due to natural causes as an effect of increased concentrations of pollutants and/or salt, caused by high temperatures; on the other side is Morawiecki’s, who fears some shenanigans by some industry operating on the river bank[7]. This division causes a delay of no less than 17 days between the discovery of the environmental damage and the official announcement of the event, which infuriates the Germans: if the Polish Prime Minister’s hypothesis turns out to be correct, as the Saxon technicians believe, Warsaw has concealed the evidence, because for days the local authorities had been reporting ‘that they had removed tonnes of dead fish from the Oder near the town of Olawa, some 300 kilometres upstream of the most recent fish die-off’[8].

The delay became a conscious and culpable decision to allow time for the river waters to dilute the concentrations of possible pollutants, but to extend their area of action. Because one thing is clear: if someone has polluted, then the scope of the investigation can be narrowed down to a small area, that of the industries, and it is enough to analyse the wastewater – as ordered by the German Environment Minister, Steffi Lemke, who has set up a joint task force to examine the causes of the fish die-off[9]. At this point, Minister Moskwa admitted that the effect of ‘a variant of the toxic substances’ had not yet been ruled out, and that ‘entities operating commercial and industrial activities along the river’ were being checked[10].

March 2022: banks of the Oder on the German-Polish border – the tragedy has already begun[11]

This at a time when no fish carcasses had yet been fished downstream in the state of Mecklenburg-Vorpommern, on Germany’s Baltic coast[12]. But the die-off continues, as confirmed by the municipal authorities of Wroclaw: ‘water authorities have detected a toxic substance at two locations in the Oder, which is probably the solvent mesitylene, known to have a harmful effect on fish’, but they add: ‘subsequent tests have shown no trace of the substance’[13]. But workers collecting the dead fish reported skin rashes after coming into contact with the river water[14].

Other factors investigated include heat and drought. In this respect, the Berlin-based Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) points out that for years the fish in the Oder have been struggling against low water levels (at least since 2018) and the effects of high water temperatures (around 25°C) – two effects of wastewater discharge, and not only industrial wastewater. In addition, the anti-erosion infrastructure built by the Poles with rock, earth and gravel reduces oxygen: ‘If fish are stressed, the rate of respiration increases’[15].

But official laboratory analyses disprove this hypothesis, because they record an oxygen content in the water higher than normal summer concentrations, and confirm the presence, in at least two sites, of poisonous concentrations of mesitylene, which then dissolved over the course of days, which would again suggest an industrial accident that occurred in July, which has also been disproved: ‘If it was released by an accident at the end of July, it should have passed through Frankfurt-on-the-Oder much earlier’[16]. All talk, according to the fishermen, who claim to have reported a serious fish die-off to the local authorities as early as March, without anyone reacting, which rules out a one-off accident and suggests a structural tragedy[17].

A new line of investigation is opened. The spokesman for the German Environment Ministry, Andreas Kübler, said that his government was ‘surprised and saddened by Warsaw’s insinuation that Germany is spreading fake-news’, and claimed that a German laboratory had been complaining for years about the indiscriminate increase in the use of pesticides and their poisonous residues in the river on the Polish side of the river[18]. From the German studies, in fact, the hypothesis that the environmental disaster of the Oder was the result of a combination of concauses, i.e. the unfavourable synergetic interaction of a deadly chemical cocktail of agricultural and industrial production with a feral toxin produced by an alga belonging to the Prymnesiumparvum species, which not only the Poles but also the Germans are dealing with, monitoring the effects and the massive quantities dissolved in many freshwater samples, seems to be increasingly credited[19].

Nevertheless, even if the algae were to be blamed for the disaster, this would not turn the catastrophe caused by mankind into a fatality. As Andreas Kübler points out, the formation of such algae on the observed scale does not occur without abnormal human intervention, as this algae can only develop in brackish water, developed due to the high salinity levels in the river, which ‘do not normally exist in the Oder except due to industrial discharges’ – a view shared by Prime Minister Morawiecki[20].

A map from GazetaWyborcza shows pollution trends along the Oder in recent weeks[21]

Berlin scientists answer: ‘IGB researchers analysed water samples from the Oder for algae, as some algal toxins are known to be problematic. The most common species found in the samples was identified as Prymnesiumparvum, which is known to produce and release strong toxins. However, genetic analysis is still ongoing. More than 100,000 prymnesium cells per millilitre were found in the samples, although this concentration had already been diluted by the influx of the Warta River. Further samples are currently being counted. The effect of the prymnesium toxins is particularly devastating not only for fish that breathe through their gills and molluscs such as mussels, but also for amphibians, as their mucous membranes and fine blood vessels are attacked and destroyed by the algae’[22].

The text continues: “Although this is only a preliminary result of the causal analysis, the IGB researchers refer to fundamental man-made problems on the Oder that increase the risk of environmental disasters. In essence, we believe that multiple negative factors have come into play” related to climate change, which “is man-made; we will experience periods of drought with increasing frequency with excessively low water levels, low oxygen levels and excessively high water temperatures. Low water levels cause an increase in the concentration of harmful substances. This extreme state is a major stress factor for fish communities. Many creatures are already struggling for survival – and if other dangers such as toxic algal blooms or chemical contamination are added to the existing pollution, entire freshwater ecosystems could be destroyed,’ concluding that the dredging infrastructure built by the Poles was the final and fatal blow[23].

While trying to understand what happened, the objective is now twofold: to understand whether something can be done to remedy, at least in part, the disaster, but for this it will be necessary to wait for mediums and hope for rain, while the damage ascertained is, even in the long term, almost irreparable: the Oder river is practically dead, and its water will no longer be drinkable for decades. The second question: is it possible that the damage will extend as far as the Baltic Sea?  The Ministry of the Environment of Mecklenburg-Vorpommern estimates that, depending on currents and winds, the estuary near Szczecin (Poland), the second largest lagoon on the Baltic, could quickly be reached by the poisons[24]. If the high concentration of mercury is confirmed, this would lead to the death of fish in Europe’s most fishy sea and to a ban on bathing at all the most famous beaches in Germany and Scandinavia – whatever crap is in the water is now being eaten and digested by all living creatures struggling in the dirty waters[25].

Let it be understood: this is only the beginning. The Oder is the first of a long series of rivers that, due to pollution and changed climatic conditions, will die in the coming years, dragging millions of tons of food with them, poisoning drinking water and water for agriculture and pastoralism, and generating colossal economic and hygienic costs. Costs that, not only today, the population of the European Union cannot pay – and does not even know how to solve the problem.




[3]https://www.theguardian.com/environment/2022/aug/15/oder-river-mystery-of-mass-die-off-of-fish-lingers-as-toxic-substances-ruled-out ; https://www.euronews.com/green/2022/08/16/nothing-was-done-for-17-days-polish-government-under-fire-for-handling-of-river-oder-crisi

[4]https://www.theguardian.com/environment/2022/aug/15/oder-river-mystery-of-mass-die-off-of-fish-lingers-as-toxic-substances-ruled-out ; https://www.ilfattoquotidiano.it/2022/08/14/disastro-ambientale-nel-fiume-oder-al-confine-fra-polonia-e-germania-milioni-di-pesci-morti/6762528/











[15]https://www.dw.com/en/mysterious-mass-fish-kill-in-oder-river-climate-change-or-poison/a-62784099  ; https://www.dw.com/en/germany-rhine-water-levels-expected-to-drop-even-further/a-62781601  ; https://www.dw.com/en/rivers-across-europe-are-too-dry-too-low-and-too-warm/a-62758853


[17]https://www.dw.com/en/mysterious-mass-fish-kill-in-oder-river-climate-change-or-poison/a-62784099 ; https://www.tagesspiegel.de/themen/brandenburg/im-winter-erstickt-tote-fische-verwesen-am-ufer/1723450.html


[19]https://www.igb-berlin.de/en/news/environmental-disaster-oder-igb-researchers-track-potentially-toxic-algae ; https://www.dw.com/en/germany-denies-polands-fake-news-claim-over-fish-deaths/a-62890278

[20]https://www.dw.com/en/germany-denies-polands-fake-news-claim-over-fish-deaths/a-62890278 ; https://www.igb-berlin.de/en/news/environmental-disaster-oder-igb-researchers-track-potentially-toxic-algae






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