2022 Oder environmental disaster

You can help expand this article with text translated from the corresponding article in Polish. Click [show] for important translation instructions. View a machine-translated version of the Polish article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Polish Wikipedia article at [[:pl:Katastrofa ekologiczna na Odrze]]; see its history for attribution. You may also add the template {{Translated|pl|Katastrofa ekologiczna na Odrze}} to the talk page. For more guidance, see Wikipedia:Translation.

You can help expand this article with text translated from the corresponding article in German. Click [show] for important translation instructions. View a machine-translated version of the German article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing German Wikipedia article at [[:de:Umweltkatastrophe in der Oder 2022]]; see its history for attribution. You may also add the template {{Translated|de|Umweltkatastrophe in der Oder 2022}} to the talk page. For more guidance, see Wikipedia:Translation.

2022 Oder environmental disaster

Dead fish in the Oder river on the border between Germany and Poland
Large-scale fish die-offs were reported in the river around Oława at the end of July[1]
Date	July–August 2022
Location	Oder
Type	Environmental disaster
Cause	Harmful algal bloom of Prymnesium parvum

During the summer of 2022, a mass mortality event involving fish, beavers, clams, crayfish and other wildlife occurred in the Oder river.

Over 100 tonnes^[2] of dead fish were removed from the Polish section of the river, and a further 35 tonnes from German sections,^[3] causing concern that the water was poisoned.

At first the cause was not clear, theories included the effects of the summer heat and lower water levels due to the European drought, reduced oxygen levels due to the heat and nutrient loading, a spike in oxygen levels due to the introduction of an oxidizing agent, and pollution by chemicals including mercury, mesitylene, salts or other sewage, as well as the possibility of an algal bloom. It was later determined to be an algal bloom.

The Polish authorities were slow to react, causing a scandal and resulting in the dismissal of officials responsible for water management and environmental protection. A reward of 1 million zlotys (about €222,000, as of September 2023) was offered for information about possible culprits.^[4]