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News article17 February 2023Directorate-General for Environment3 min read

Zero Pollution: New report draws lessons from the Oder River ecological disaster

Peninsula in river surrounded by green landscape.

An EU report published today analyses the massive fish kill in the Oder River in July and August 2022, one of the largest ecological disasters in Europe in recent memory. The analysis by the Commission (Joint Research Centre) and European Environment Agency identifies the likely causes and proposes recommendations to help prevent such catastrophes from happening again.

Commissioner for the Environment, Oceans and Fisheries, Virginijus Sinkevičius, said:

The 2022 Oder River fish kill was a stark reminder of how human induced pollution, coupled with biodiversity loss and climate change, can create a perfect storm, with dire consequences for people, the economy and planet. We cannot allow a similar disaster to ever happen again. We need our rivers for fresh drinking water, our livelihoods and our ecosystems. I warmly welcome this new report and invite competent national authorities to rigorously implement its recommendations. The full implementation of the current legislation and our proposed improvements to EU laws on industrial emissions, surface and ground water pollutants and treatment of urban wastewater will be our shield against such disasters in the future.

According to the scientific evidence in the report, the deaths of around 360 tonnes of fish were caused by a substantial toxic algal bloom identified as Prymnesium parvum. A key factor that enabled the proliferation of this brackish water species is most likely the high salinity of the Oder River during this time, resulting from discharges of industrial wastewater with a high salt content e.g. from industrial activities such as mining.

Other contributing factors were the drought and the resulting low water levels reducing dilution and flow. Elevated nutrient concentrations, especially phosphorus and nitrogen, are also a key component in promoting such blooms.

Given the continued presence and spread of this invasive algal species, management strategies to prevent future occurrence of events of this nature must now be prioritised not only in the Oder catchment but also in other susceptible European river basin districts, which the report indicates.

The prevention of future disasters is one of the commitments the EU will be bringing forward at the forthcoming landmark UN Water Conference in March. Indeed, recent legislative proposals from the Commission will serve to strengthen even further existing EU environmental legislation. Emissions to water from large industrial installations are regulated by the Industrial Emissions Directive, which the Commission has proposed to strengthen to further reduce emissions to water and air. The Commission’s proposal to strengthen the law on treatment of wastewater will contribute further to preventing nutrient pollution and resulting algae blooms, when adopted. In the event of future pollution incidents, the Commission’s proposal on water pollutants, includes a mandatory warning clause.

The report highlights key recommendations to prevent future ecological disasters in EU rivers:

  • Improve knowledge and monitoring.
  • Improve proactive communication to stakeholders, public and countries downstream.
  • Improve response and risk management (anticipate responses and prepare resources).
  • Review and verify existing permits and increase enforcement.
  • Introduce provisions for allowable pollutant loads to be adapted to the water levels in the recipient waters.
  • List all industrial discharges in a complete and up to date public inventory of emissions (European Industrial Emissions Portal (
  • Further investigate the source of the incident (while a multifactorial event, sources of discharges of saline material should be identified and checked against permits, compare to long term salinity levels).
  • Improve environmental management (hydromorphological changes, salinity /nutrient thresholds).
  • Start restoration (inventory of damage, develop plan for restoration of the river).
  • Undertake research to improve knowledge and help prevent algae growth and salinisation.


Publication date
17 February 2023
Directorate-General for Environment

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